679 results on '"Leo P"'
Search Results
2. Robust poor man's Majorana zero modes using Yu-Shiba-Rusinov states.
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Zatelli, Francesco, van Driel, David, Xu, Di, Wang, Guanzhong, Liu, Chun-Xiao, Bordin, Alberto, Roovers, Bart, Mazur, Grzegorz P., van Loo, Nick, Wolff, Jan C., Bozkurt, A. Mert, Badawy, Ghada, Gazibegovic, Sasa, Bakkers, Erik P. A. M., Wimmer, Michael, Kouwenhoven, Leo P., and Dvir, Tom
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QUANTUM states ,QUANTUM information science ,BOUND states ,SUPERCONDUCTORS ,SUPERCONDUCTIVITY - Abstract
Kitaev chains in quantum dot-superconductor arrays are a promising platform for the realization of topological superconductivity. As recently demonstrated, even a two-site chain can host Majorana zero modes known as "poor man's Majorana". Harnessing the potential of these states for quantum information processing, however, requires increasing their robustness to external perturbations. Here, we form a two-site Kitaev chain using Yu-Shiba-Rusinov states in proximitized quantum dots. By deterministically tuning the hybridization between the quantum dots and the superconductor, we observe poor man's Majorana states with a gap larger than 70 μeV. The sensitivity to charge fluctuations is also greatly reduced compared to Kitaev chains made with non-proximitized dots. The systematic control and improved energy scales of poor man's Majorana states realized with Yu-Shiba-Rusinov states will benefit the realization of longer Kitaev chains, parity qubits, and the demonstration of non-Abelian physics. A Kitaev chain formed by two quantum dots coupled via a superconductor support the so-called poor man's Majorana bound states. Here, the authors form a minimal Kitaev chain using Yu-Shiba-Rusinov states and show that the resulting bound states are more robust than in the case of unproximitized quantum dots. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Carex scirpoidea (Cyperaceae) in Wisconsin—Now you see it...
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Bruederle, Leo P., Spencer, Audrey, and Bard, Nicholas W.
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DATA libraries ,CAREX ,CYPERACEAE ,HERBARIA ,SPECIES - Abstract
A search of herbarium data repositories available online revealed a notable collection of Carex scirpoidea (Cyperaceae) made by Joachim Heinrich Schuette in 1884 from Brown Co., Wisconsin, USA. This accession is the first and only known record of this now extirpated species from the state. While this locality represents a modest expansion of the known range of C. scirpoidea, errors in the aforementioned databases resulting from the complex nomenclatural history of this taxon confound our understanding of its distribution, particularly along its southern edge in the Midwest and Eastern North America. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Real world predictors of response and 24-month survival in high-grade TP53-mutated myeloid neoplasms.
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Kaur, Amandeep, Rojek, Alexandra E., Symes, Emily, Nawas, Mariam T., Patel, Anand A., Patel, Jay L., Sojitra, Payal, Aqil, Barina, Sukhanova, Madina, McNerney, Megan E., Wu, Leo P., Akmatbekov, Aibek, Segal, Jeremy, Tjota, Melissa Y., Gurbuxani, Sandeep, Cheng, Jason X., Yeon, Su-Yeon, Ravisankar, Harini V., Fitzpatrick, Carrie, and Lager, Angela
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DISEASE risk factors ,STEM cell transplantation ,MOLECULAR pathology ,TUMORS ,BLAST injuries - Abstract
Current therapies for high-grade TP53-mutated myeloid neoplasms (≥10% blasts) do not offer a meaningful survival benefit except allogeneic stem cell transplantation in the minority who achieve a complete response to first line therapy (CR1). To identify reliable pre-therapy predictors of complete response to first-line therapy (CR1) and outcomes, we assembled a cohort of 242 individuals with TP53-mutated myeloid neoplasms and ≥10% blasts with well-annotated clinical, molecular and pathology data. Key outcomes examined were CR1 & 24-month survival (OS24). In this elderly cohort (median age 68.2 years) with 74.0% receiving frontline non-intensive regimens (hypomethylating agents +/- venetoclax), the overall cohort CR1 rate was 25.6% (50/195). We additionally identified several pre-therapy factors predictive of inferior CR1 including male gender (P = 0.026), ≥2 autosomal monosomies (P < 0.001), −17/17p (P = 0.011), multi-hit TP53 allelic state (P < 0.001) and CUX1 co-alterations (P = 0.010). In univariable analysis of the entire cohort, inferior OS24 was predicated by ≥2 monosomies (P = 0.004), TP53 VAF > 25% (P = 0.002), TP53 splice junction mutations (P = 0.007) and antecedent treated myeloid neoplasm (P = 0.001). In addition, mutations/deletions in CUX1, U2AF1, EZH2, TET2, CBL, or KRAS ('EPI6' signature) predicted inferior OS24 (HR = 2.0 [1.5–2.8]; P < 0.0001). In a subgroup analysis of HMA +/-Ven treated individuals (N = 144), TP53 VAF and monosomies did not impact OS24. A risk score for HMA +/-Ven treated individuals incorporating three pre-therapy predictors including TP53 splice junction mutations, EPI6 and antecedent treated myeloid neoplasm stratified 3 prognostic distinct groups: intermediate, intermediate-poor, and poor with significantly different median (12.8, 6.0, 4.3 months) and 24-month (20.9%, 5.7%, 0.5%) survival (P < 0.0001). For the first time, in a seemingly monolithic high-risk cohort, our data identifies several baseline factors that predict response and 24-month survival. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Tractography-based DBS lead repositioning improves outcome in refractory OCD and depression.
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Basich-Pease, Genevieve, Slepneva, Natalya, Frank, Adam C., Norbu, Tenzin, Morrison, Melanie A., Sugrue, Leo P., Larson, Paul S., Starr, Philip A., and Lee, A. Moses
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OBSESSIVE-compulsive disorder ,DEEP brain stimulation ,PREFRONTAL cortex ,WHITE matter (Nerve tissue) ,MENTAL depression - Abstract
Deep brain stimulation (DBS) of the anterior limb of the internal capsule (ALIC) has been used to treat refractory obsessive-compulsive disorder (OCD) and depression, but outcomes are variable, with some patients not responding to this form of invasive neuromodulation. A lack of benefit in some patients may be due to suboptimal positioning of DBS leads. Recently, studies have suggested that specific white matter tracts within the ALIC are associated with improved outcomes. Here, we present the case of a patient who initially had a modest improvement in OCD and depressive symptoms after receiving DBS within the ALIC. Subsequently, he underwent unilateral DBS lead repositioning informed by tractography targeting the ventrolateral and medial prefrontal cortex’s connection with the mediodorsal thalamus. In this patient, we also conducted post-implant and post-repositioning diffusion imaging and found that we could successfully perform tractography even with DBS leads in place. Following lead repositioning into tracts predictive of benefit, the patient reached responder criteria for his OCD, and his depression was remitted. This case illustrates that tractography can potentially be used in the evaluation and planning of lead repositioning to achieve therapeutic outcomes. [ABSTRACT FROM AUTHOR]
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- 2024
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6. The University of West Florida Campus Ecosystem Study: effects of forest vegetation on light availability and soil processes.
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Gilliam, Frank S., Currey, Alayna L., Young, Leo P., Davis, Brenton C., and Perry, Caden M.
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FOREST plants ,LONGLEAF pine ,SOILS ,SOLAR radiation ,HARDWOODS - Abstract
College and university campuses with a notable arboreal component provide unique opportunities for carrying out ecological research. The University of West Florida Campus Ecosystem Study (UWF CES) was established in 2019 as interconnected research to take advantage of the extensive arborescent nature of the UWF campus, particularly concerning longleaf pine (Pinus palustris). One of these investigations established permanent plots in forested sites of two contrasting types, one dominated by longleaf pine ("pine site") and the other dominated by hardwoods ('hardwood site'). This study used these plots to examine the influence of forest vegetation on light availability and soil processes. Light was measured as photosynthetically active radiation (and expressed as photon flux density—PFD) with a handheld meter in each plot. Soil was sampled to 5 cm in each plot; texture was measured with the hydrometer method. Identical sampling methods were carried out in a persistent canopy opening to assess light and soil conditions under maximum solar radiation. Mean PFD was ~4× higher in pine stands than in hardwood stands; PFD was 12.8 and 3.5% of full light in the pine and hardwood stands, respectively. All soils were dominated by coarse-textured sands, but silt was significantly higher in pine stand soil and higher still in the canopy opening. Among forest stand plots, sand was negatively related to PFD, whereas clay was positively related to PFD. Across the three sites, silt was positively related to PFD. These relationships are consistent with the importance of solar radiation as one of many drivers of soil weathering. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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7. 3D U-Net for automated detection of multiple sclerosis lesions: utility of transfer learning from other pathologies.
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Wahlig, Stephen G., Nedelec, Pierre, Weiss, David A., Rudie, Jeffrey D., Sugrue, Leo P., and Rauschecker, Andreas M.
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MULTIPLE sclerosis ,MACHINE learning ,CONVOLUTIONAL neural networks ,PATHOLOGY ,DEEP learning - Abstract
Background and purpose: Deep learning algorithms for segmentation of multiple sclerosis (MS) plaques generally require training on large datasets. This manuscript evaluates the effect of transfer learning from segmentation of another pathology to facilitate use of smaller MS-specific training datasets. That is, a model trained for detection of one type of pathology was re-trained to identify MS lesions and active demyelination. Materials and methods: In this retrospective study using MRI exams from 149 patients spanning 4/18/2014 to 7/8/2021, 3D convolutional neural networks were trained with a variable number of manually-segmented MS studies. Models were trained for FLAIR lesion segmentation at a single timepoint, new FLAIR lesion segmentation comparing two timepoints, and enhancing (actively demyelinating) lesion segmentation on T1 post-contrast imaging. Models were trained either denovo or fine-tuned with transfer learning applied to a pre-existing model initially trained on non-MS data. Performance was evaluated with lesionwise sensitivity and positive predictive value (PPV). Results: For single timepoint FLAIR lesion segmentation with 10 training studies, a fine-tuned model demonstrated improved performance [lesionwise sensitivity 0.55 ± 0.02 (mean ± standard error), PPV 0.66 ± 0.02] compared to a de-novo model (sensitivity 0.49 ± 0.02, p = 0.001; PPV 0.32 ± 0.02, p < 0.001). For new lesion segmentation with 30 training studies and their prior comparisons, a fine-tuned model demonstrated similar sensitivity (0.49 ± 0.05) and significantly improved PPV (0.60 ± 0.05) compared to a de-novo model (sensitivity 0.51 ± 0.04, p = 0.437; PPV 0.43 ± 0.04, p = 0.002). For enhancement segmentation with 20 training studies, a fine-tuned model demonstrated significantly improved overall performance (sensitivity 0.74 ± 0.06, PPV 0.69 ± 0.05) compared to a de-novo model (sensitivity 0.44 ± 0.09, p = 0.001; PPV 0.37 ± 0.05, p = 0.001). Conclusion: By fine-tuning models trained for other disease pathologies with MS-specific data, competitive models identifying existing MS plaques, new MS plaques, and active demyelination can be built with substantially smaller datasets than would otherwise be required to train new models. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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8. Spin-filtered measurements of Andreev bound states in semiconductor-superconductor nanowire devices.
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van Driel, David, Wang, Guanzhong, Bordin, Alberto, van Loo, Nick, Zatelli, Francesco, Mazur, Grzegorz P., Xu, Di, Gazibegovic, Sasa, Badawy, Ghada, Bakkers, Erik P. A. M., Kouwenhoven, Leo P., and Dvir, Tom
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NANOWIRE devices ,SEMICONDUCTOR nanowires ,NANOWIRES ,EXCITATION spectrum ,SPIN-orbit interactions ,SPIN excitations ,EXCITED states - Abstract
Semiconductor nanowires coupled to superconductors can host Andreev bound states with distinct spin and parity, including a spin-zero state with an even number of electrons and a spin-1/2 state with odd-parity. Considering the difference in spin of the even and odd states, spin-filtered measurements can reveal the underlying ground state. To directly measure the spin of single-electron excitations, we probe an Andreev bound state using a spin-polarized quantum dot that acts as a bipolar spin filter, in combination with a non-polarized tunnel junction in a three-terminal circuit. We observe a spin-polarized excitation spectrum of the Andreev bound state, which can be fully spin-polarized, despite strong spin-orbit interaction in the InSb nanowires. Decoupling the hybrid from the normal lead causes a current blockade, by trapping the Andreev bound state in an excited state. Spin-polarized spectroscopy of hybrid nanowire devices, as demonstrated here, is proposed as an experimental tool to support the observation of topological superconductivity. Andreev bound states can form in hybrid semiconducting-superconducting devices and can mirror the experimental signatures of the much sought topologically non-trivial Majorana bound states. Here, van Driel, Wang and coauthors present a method of directly measuring the spin-polarized excitation spectrum of Andreev bound states. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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9. Subgap spectroscopy along hybrid nanowires by nm-thick tunnel barriers.
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Levajac, Vukan, Wang, Ji-Yin, Sfiligoj, Cristina, Lemang, Mathilde, Wolff, Jan Cornelis, Bordin, Alberto, Badawy, Ghada, Gazibegovic, Sasa, Bakkers, Erik P. A. M., and Kouwenhoven, Leo P.
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NANOWIRES ,TUNNELING spectroscopy ,SUPERCONDUCTORS ,SPECTROMETRY - Abstract
Tunneling spectroscopy is widely used to examine the subgap spectra in semiconductor-superconductor nanostructures when searching for Majorana zero modes (MZMs). Typically, semiconductor sections controlled by local gates at the ends of hybrids serve as tunnel barriers. Besides detecting states only at the hybrid ends, such gate-defined tunnel probes can cause the formation of non-topological subgap states that mimic MZMs. Here, we develop an alternative type of tunnel probes to overcome these limitations. After the growth of an InSb-Al hybrid nanowire, a precisely controlled in-situ oxidation of the Al shell is performed to yield a nm-thick AlOx layer. In such thin isolating layer, tunnel probes can be arbitrarily defined at any position along the hybrid nanowire by shadow-wall angle-deposition of metallic leads. In this work, we make multiple tunnel probes along single nanowire hybrids and successfully identify Andreev bound states (ABSs) of various spatial extension residing along the hybrids. Tunneling spectroscopy is widely used to examine the subgap spectra in semiconductor/superconductor nanostructures. Here, the authors develop an alternative type of tunnel probe for InSb-Al hybrid nanowires, enabling study of the spatial extension of Andreev bound states. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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10. Lesioning the Brain—From Serendipity to Science.
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Sugrue, Leo P., Lashof-Regas, Samuel, and Wang, Doris D.
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- 2024
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11. Myeloid sarcoma with NPM1 mutation may be clinically and genetically distinct from AML with NPM1 mutation: a study from the Bone Marrow Pathology Group.
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Ramia de Cap, Maximiliano, Wu, Leo P., Hirt, Christian, Pihan, German A., Patel, Sanjay S., Tam, Wayne, Bueso-Ramos, Carlos E., Kanagal-Shamanna, Rashmi, Raess, Philipp W., Siddon, Alexa, Narayanan, Damodaran, Morgan, Elizabeth A., Pinkus, Geraldine S., Mason, Emily F., Hsi, Eric D., Rogers, Heesun J., Toth, Laura, Foucar, Kathryn, Hurwitz, Stephanie N., and Bagg, Adam
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MYELOID sarcoma ,ACUTE myeloid leukemia ,BONE marrow ,GENETIC profile ,PATHOLOGY - Abstract
Myeloid sarcoma (MS) is currently considered equivalent to de novo acute myeloid leukemia (AML); however, the relationship between these entities is poorly understood. This retrospective multi-institutional cohort study compared 43 MS with NPM1 mutation to 106 AML with NPM1 mutation. Compared to AML, MS had more frequent cytogenetic abnormalities including complex karyotype (p =.009 and p =.007, respectively) and was enriched in mutations of genes involved in histone modification, including ASXL1 (p =.007 and p =.008, respectively). AML harbored a higher average number of gene mutations (p =.002) including more frequent PTPN11 mutations (p <.001) and mutations of DNA-methylating genes including DNMT3A and IDH1 (both p <.001). MS had significantly shorter overall survival (OS) than AML (median OS: 44.9 vs. 93.2 months, respectively, p =.037). MS with NPM1 mutation has a unique genetic landscape, and poorer OS, compared to AML with NPM1 mutation. First study comparing genetic profiles of MS and AML with a common disease-defining lesion. NPM1
Mut MS may be genetically distinct from NPM1Mut AML. NPM1Mut MS may have inferior overall survival compared to NPM1Mut AML. [ABSTRACT FROM AUTHOR]- Published
- 2023
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12. PRNP expression predicts imaging findings in sporadic Creutzfeldt‐Jakob disease.
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Broce, Iris J., Caverzasi, Eduardo, Sacco, Simone, Nillo, Ryan Michael, Paoletti, Matteo, Desikan, Rahul S., Geschwind, Michael, and Sugrue, Leo P.
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CREUTZFELDT-Jakob disease ,CEREBRAL atrophy ,CEREBRAL cortex ,PRIONS - Abstract
Objective: We explored the relationship between regional PRNP expression from healthy brain tissue and patterns of increased and decreased diffusion and regional brain atrophy in patients with sporadic Creutzfeldt‐Jakob disease (sCJD). Methods: We used PRNP microarray data from 6 healthy adult brains from Allen Brain Institute and T1‐weighted and diffusion‐weighted MRIs from 34 patients diagnosed with sCJD and 30 age‐ and sex‐matched healthy controls to construct partial correlation matrices across brain regions for specific measures of interest: PRNP expression, mean diffusivity, volume, cortical thickness, and local gyrification index, a measure of cortical folding. Results: Regional patterns of PRNP expression in the healthy brain correlated with regional patterns of diffusion signal abnormalities and atrophy in sCJD. Among different measures of cortical morphology, regional patterns of local gyrification index in sCJD most strongly correlated with regional patterns of PRNP expression. At the vertex‐wise level, different molecular subtypes of sCJD showed distinct regional correlations in local gyrification index across the cortex. Local gyrification index correlation patterns most closely matched patterns of PRNP expression in sCJD subtypes known to have greatest pathologic involvement of the cerebral cortex. Interpretation: These results suggest that the specific genetic and molecular environment in which the prion protein is expressed confer variable vulnerability to misfolding across different brain regions that is reflected in patterns of imaging findings in sCJD. Further work in larger samples will be needed to determine whether these regional imaging patterns can serve as reliable markers of distinct disease subtypes to improve diagnosis and treatment targeting. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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13. Epigenetic age from peripheral blood predicts progression to Alzheimer's disease, white matter disease burden, and cortical atrophy.
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Bonham, Luke W., Sirkis, Daniel W., Pang, Alina PS, Sugrue, Leo P, Santamaría‐García, Hernando A, Ibanez, Agustin, Miller, Bruce L, Yokoyama, Jennifer S., and Corley, Michael J
- Published
- 2023
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14. Prospects of Gravitational-wave Follow-up through a Wide-field Ultraviolet Satellite: A Dorado Case Study.
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Dorsman, Bas, Raaijmakers, Geert, Cenko, S. Bradley, Nissanke, Samaya, Singer, Leo P., Kasliwal, Mansi M., Piro, Anthony L., Bellm, Eric C., Hartmann, Dieter H., Hotokezaka, Kenta, and Lukošiūtė, Kamilė
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LIGHT curves ,STELLAR mergers ,BAYESIAN analysis ,ASTRONOMY ,BINARY stars ,GRAVITATIONAL waves ,NEUTRON capture - Abstract
The detection of gravitational waves from the binary neuron star merger GW170817 and electromagnetic counterparts GRB170817A and AT2017gfo kick-started the field of gravitational-wave multimessenger astronomy. The optically red to near-infrared emission ("red" component) of AT2017gfo was readily explained as produced by the decay of newly created nuclei produced by rapid neutron capture (a kilonova). However, the ultraviolet to optically blue emission ("blue" component) that was dominant at early times (up to 1.5 days) received no consensus regarding its driving physics. Among many explanations, two leading contenders are kilonova radiation from a lanthanide-poor ejecta component and shock interaction (cocoon emission). In this work, we simulate AT2017gfo-like light curves and perform a Bayesian analysis to study whether an ultraviolet satellite capable of rapid gravitational-wave follow-up, could distinguish between physical processes driving the early "blue" component. We find that ultraviolet data starting at 1.2 hr distinguishes the two early radiation models up to 160 Mpc, implying that an ultraviolet mission like Dorado would significantly contribute to insights into the driving emission physics of the postmerger system. While the same ultraviolet data and optical data starting at 12 hr have limited ability to constrain model parameters separately, the combination of the two unlocks tight constraints for all but one parameter of the kilonova model up to 160 Mpc. We further find that a Dorado-like ultraviolet satellite can distinguish the early radiation models up to at least 130 (60) Mpc if data collection starts within 3.2 (5.2) hr for AT2017gfo-like light curves. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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15. Singlet and triplet Cooper pair splitting in hybrid superconducting nanowires.
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Wang, Guanzhong, Dvir, Tom, Mazur, Grzegorz P., Liu, Chun-Xiao, van Loo, Nick, ten Haaf, Sebastiaan L. D., Bordin, Alberto, Gazibegovic, Sasa, Badawy, Ghada, Bakkers, Erik P. A. M., Wimmer, Michael, and Kouwenhoven, Leo P.
- Abstract
In most naturally occurring superconductors, electrons with opposite spins form Cooper pairs. This includes both conventional s-wave superconductors such as aluminium, as well as high-transition-temperature, d-wave superconductors. Materials with intrinsic p-wave superconductivity, hosting Cooper pairs made of equal-spin electrons, have not been conclusively identified, nor synthesized, despite promising progress1–3. Instead, engineered platforms where s-wave superconductors are brought into contact with magnetic materials have shown convincing signatures of equal-spin pairing4–6. Here we directly measure equal-spin pairing between spin-polarized quantum dots. This pairing is proximity-induced from an s-wave superconductor into a semiconducting nanowire with strong spin–orbit interaction. We demonstrate such pairing by showing that breaking a Cooper pair can result in two electrons with equal spin polarization. Our results demonstrate controllable detection of singlet and triplet pairing between the quantum dots. Achieving such triplet pairing in a sequence of quantum dots will be required for realizing an artificial Kitaev chain7–9.Controllable detection of singlet and triplet Cooper pair splitting via crossed Andreev reflection is demonstrated in spin-polarized quantum dots on a superconducting nanowire platform with strong spin–orbit coupling. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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16. Spin‐Mixing Enhanced Proximity Effect in Aluminum‐Based Superconductor–Semiconductor Hybrids.
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Mazur, Grzegorz P., van Loo, Nick, Wang, Ji‐Yin, Dvir, Tom, Wang, Guanzhong, Khindanov, Aleksei, Korneychuk, Svetlana, Borsoi, Francesco, Dekker, Robin C., Badawy, Ghada, Vinke, Peter, Gazibegovic, Sasa, Bakkers, Erik P. A. M., Pérez, Marina Quintero‐, Heedt, Sebastian, and Kouwenhoven, Leo P.
- Published
- 2022
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17. Stable and Discriminatory Radiomic Features from the Tumor and Its Habitat Associated with Progression-Free Survival in Glioblastoma: A Multi-Institutional Study.
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Verma, R., Hill, V. B., Statsevych, V., Bera, K., Correa, R., Leo, P., Ahluwalia, M., Madabhushi, A., and Tiwari, P.
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- 2022
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18. Foraging with MUSHROOMS: A Mixed-integer Linear Programming Scheduler for Multimessenger Target of Opportunity Searches with the Zwicky Transient Facility.
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Parazin, B., Coughlin, Michael W., Singer, Leo P., Gupta, Vaidehi, and Anand, Shreya
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LINEAR programming ,OPERATIONS research ,MIXED integer linear programming ,STELLAR mergers ,GRAVITATIONAL wave astronomy ,NEUTRON stars ,BINARY stars - Abstract
Electromagnetic follow-up of gravitational-wave detections is very resource intensive, taking up hours of limited observation time on dozens of telescopes. Creating more efficient schedules for follow-up will lead to a commensurate increase in counterpart location efficiency without using more telescope time. Widely used in operations research and telescope scheduling, mixed-integer linear programming is a strong candidate to produce these higher-efficiency schedules, as it can make use of powerful commercial solvers that find globally optimal solutions to provided problems. We detail a new target-of-opportunity scheduling algorithm designed with Zwicky Transient Facility in mind that uses mixed-integer linear programming. We compare its performance to gwemopt, the tuned heuristic scheduler used by the Zwicky Transient Facility and other facilities during the third LIGOâ€"Virgo gravitational-wave observing run. This new algorithm uses variable-length observing blocks to enforce cadence requirements and to ensure field observability, along with having a secondary optimization step to minimize slew time. We show that by employing a hybrid method utilizing both this scheduler and gwemopt, the previous scheduler used, in concert, we can achieve an average improvement in detection efficiency of 3%â€"11% over gwemopt alone for a simulated binary neutron star merger data set consistent with LIGOâ€"Virgo’s third observing run, highlighting the potential of mixed-integer target of opportunity schedulers for future multimessenger follow-up surveys. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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19. Factors affecting safety performance in the construction industry: an empirical study using structural equation modelling.
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Moosa, Majed H. and Oriet, Leo P.
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CONSTRUCTION industry safety ,STRUCTURAL equation modeling ,SAFETY factor in engineering ,RISK perception ,EMPIRICAL research - Abstract
The Saudi construction industry is among the largest in the region – and, for workers, among the most dangerous industries. The importance of this study is assisting to reduce hazards, sources of risk and perceptions of safety in the construction sector. Using a quantitative survey measure administered to a small (n = 276) sample of individuals, this study aimed to contribute to empirical understandings of safety performance in this unique context. A multivariate safety performance model was developed to ensure compatibility with the structure of the survey measure. The survey data revealed a strong consensus expressing negative views of every safety dimension and variable tested, with only tiny minorities selecting positively valenced responses. To test the descriptive power of the model as a whole, a structural equation modelling technique was used to assess the correspondence between the relationships constituting the model and their significance relative to empirical data. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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20. HEALPix Alchemy: Fast All-Sky Geometry and Image Arithmetic in a Relational Database for Multimessenger Astronomy Brokers.
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Singer, Leo P., Parazin, B., Coughlin, Michael W., Bloom, Joshua S., Crellin-Quick, Arien, Goldstein, Daniel A., and van der Walt, Stéfan
- Published
- 2022
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21. Inferring Kilonova Population Properties with a Hierarchical Bayesian Framework. I. Nondetection Methodology and Single-event Analyses.
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Mohite, Siddharth R., Rajkumar, Priyadarshini, Anand, Shreya, Kaplan, David L., Coughlin, Michael W., Sagués-Carracedo, Ana, Saleem, Muhammed, Creighton, Jolien, Brady, Patrick R., Ahumada, Tomás, Almualla, Mouza, Andreoni, Igor, Bulla, Mattia, Graham, Matthew J., Kasliwal, Mansi M., Kaye, Stephen, Laher, Russ R., Shin, Kyung Min, Shupe, David L., and Singer, Leo P.
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ASTRONOMICAL surveys ,BEACHES - Abstract
We present nimbus: a hierarchical Bayesian framework to infer the intrinsic luminosity parameters of kilonovae (KNe) associated with gravitational-wave (GW) events, based purely on nondetections. This framework makes use of GW 3D distance information and electromagnetic upper limits from multiple surveys for multiple events and self-consistently accounts for the finite sky coverage and probability of astrophysical origin. The framework is agnostic to the brightness evolution assumed and can account for multiple electromagnetic passbands simultaneously. Our analyses highlight the importance of accounting for model selection effects, especially in the context of nondetections. We show our methodology using a simple, two-parameter linear brightness model, taking the follow-up of GW190425 with the Zwicky Transient Facility as a single-event test case for two different prior choices of model parameters: (i) uniform/uninformative priors and (ii) astrophysical priors based on surrogate models of Monte Carlo radiative-transfer simulations of KNe. We present results under the assumption that the KN is within the searched region to demonstrate functionality and the importance of prior choice. Our results show consistency with simsurveyâ€"an astronomical survey simulation tool used previously in the literature to constrain the population of KNe. While our results based on uniform priors strongly constrain the parameter space, those based on astrophysical priors are largely uninformative, highlighting the need for deeper constraints. Future studies with multiple events having electromagnetic follow-up from multiple surveys should make it possible to constrain the KN population further. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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22. Data-driven Expectations for Electromagnetic Counterpart Searches Based on LIGO/Virgo Public Alerts.
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Petrov, Polina, Singer, Leo P., Coughlin, Michael W., Kumar, Vishwesh, Almualla, Mouza, Anand, Shreya, Bulla, Mattia, Dietrich, Tim, Foucart, Francois, and Guessoum, Nidhal
- Subjects
GAMMA ray bursts ,STELLAR mergers ,NEUTRON stars ,BINARY stars ,DATA release ,ENTERPRISE resource planning - Abstract
Searches for electromagnetic counterparts of gravitational-wave signals have redoubled since the first detection in 2017 of a binary neutron star merger with a gamma-ray burst, optical/infrared kilonova, and panchromatic afterglow. Yet, one LIGO/Virgo observing run later, there has not yet been a second, secure identification of an electromagnetic counterpart. This is not surprising given that the localization uncertainties of events in LIGO and Virgo's third observing run, O3, were much larger than predicted. We explain this by showing that improvements in data analysis that now allow LIGO/Virgo to detect weaker and hence more poorly localized events have increased the overall number of detections, of which well-localized, gold-plated events make up a smaller proportion overall. We present simulations of the next two LIGO/Virgo/KAGRA observing runs, O4 and O5, that are grounded in the statistics of O3 public alerts. To illustrate the significant impact that the updated predictions can have, we study the follow-up strategy for the Zwicky Transient Facility. Realistic and timely forecasting of gravitational-wave localization accuracy is paramount given the large commitments of telescope time and the need to prioritize which events are followed up. We include a data release of our simulated localizations as a public proposal planning resource for astronomers. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
23. Optimizing Cadences with Realistic Light-curve Filtering for Serendipitous Kilonova Discovery with Vera Rubin Observatory.
- Author
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Andreoni, Igor, Coughlin, Michael W., Almualla, Mouza, Bellm, Eric C., Bianco, Federica B., Bulla, Mattia, Cucchiara, Antonino, Dietrich, Tim, Goobar, Ariel, Kool, Erik C., Li, Xiaolong, Ragosta, Fabio, Sagués-Carracedo, Ana, and Singer, Leo P.
- Published
- 2022
- Full Text
- View/download PDF
24. Denoising With Inherent Scattering Characteristic for 2-D Radar Cross Section Measurement.
- Author
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Hu, Weidong, Liu, Yang, Si, Weikang, Yao, Zhiyu, Zhao, Peng, and Ligthart, Leo P.
- Abstract
Noises from the measurement sensors are inevitable in radar cross Section testing due to the thermal agitation of electrons in imperfect conductors. Existing methods represented by wavelet threshold usually regard the measured data as a stationary stochastic signal, ignoring the inherent influence of the target under test, which inevitably removes the signal’s component when noise increases. This paper proposes a novel perspective on 2-D radar cross Section measurement denoising, considering the target’s inherent scattering characteristics (ISC). In the proposed method, the noise and the target are firstly separated as far as possible in the generalized Fourier series domain while the target’s component is all preserved. Then, the noise is further suppressed by the scattered field reconstruction of the Hankel function. Finally, a metal sphere being a calibrator is introduced to improve the denoising ability. Both simulations and experimental studies demonstrate the superiority of our method compared with existing algorithms. Results indicate that the proposed method can achieve higher accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
25. Longitudinal analysis of regional brain changes in anti-NMDAR encephalitis: a case report.
- Author
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Nillo, Ryan M., Broce, Iris J., Uzgil, Besim, Singhal, Nilika S., Glastonbury, Christine M., Hess, Christopher P., Barkovich, James A., Desikan, Rahul S., and Sugrue, Leo P.
- Subjects
ENCEPHALITIS ,ANTI-NMDA receptor encephalitis ,DIAGNOSIS ,OCCIPITAL lobe ,SYMPTOMS ,ADULTS ,PATHOLOGICAL physiology - Abstract
Background: Anti-NMDA receptor encephalitis is an immune-mediated disorder characterized by antibodies against the GluN1 subunit of the NMDA receptor that is increasingly recognized as a treatable cause of childhood epileptic encephalopathy. In adults, the disorder has been associated with reversible changes in brain volume over the course of treatment and recovery, but in children, little is known about its time course and associated imaging manifestations.Case Presentation: A previously healthy 20-month-old boy presented with first-time unprovoked seizures, dysautonomia, and dyskinesia. Paraneoplastic workup was negative, but CSF was positive for anti-NMDAR antibodies. The patient's clinical condition waxed and waned over a 14-month course of treatment with first- and second-line immunotherapies (including steroids, IVIG, rituximab, and cyclophosphamide). Serial brain MRIs scans obtained at 5 time points spanning this same period showed no abnormal signal or enhancement but were remarkable for cycles of reversible regional cortical volume loss. All scans included identical 1-mm resolution 3D T1-weighted sequences obtained on the same 3 T scanner. Using a novel longitudinal processing stream in FreeSurfer6 (Reuter M, et. al, Neuroimage 61:1402-18, 2012) we quantified the rate of change in cortical volume at each vertex (% volume change per month) between consecutive scans and correlated these changes with the time course of the patient's treatment and clinical response. We found regionally specific changes in cortical volume (up to 7% per month) that preferentially affected the frontal and occipital lobes and paralleled the patient's clinical course, with clinical decline associated with volume loss and clinical improvement associated with volume gain.Conclusions: Our results suggest that reversible cortical volume loss in anti-NMDA encephalitis has a regional specificity that mirrors many of the clinical symptoms associated with the disorder and tracks the dynamics of disease severity over time. This case illustrates how quantitative morphometric techniques can be applied to clinical imaging data to reveal patterns of brain change that may provide insight into disease pathophysiology. More widespread application of this approach might reveal regional and temporal patterns specific to different types of autoimmune encephalitis, providing a tool for diagnosis and a surrogate marker for monitoring treatment response. [ABSTRACT FROM AUTHOR]- Published
- 2021
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26. Fast-transient Searches in Real Time with ZTFReST: Identification of Three Optically Discovered Gamma-Ray Burst Afterglows and New Constraints on the Kilonova Rate.
- Author
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Andreoni, Igor, Coughlin, Michael W., Kool, Erik C., Kasliwal, Mansi M., Kumar, Harsh, Bhalerao, Varun, Carracedo, Ana Sagués, Ho, Anna Y. Q., Pang, Peter T. H., Saraogi, Divita, Sharma, Kritti, Shenoy, Vedant, Burns, Eric, Ahumada, Tomás, Anand, Shreya, Singer, Leo P., Perley, Daniel A., De, Kishalay, Fremling, U. C., and Bellm, Eric C.
- Subjects
GAMMA ray bursts ,STELLAR mergers ,GAMMA ray astronomy ,NEUTRON stars ,BINARY stars ,SUPERNOVAE ,OBSERVATORIES - Abstract
The most common way to discover extragalactic fast transients, which fade within a few nights in the optical, is via follow-up of gamma-ray burst and gravitational-wave triggers. However, wide-field surveys have the potential to identify rapidly fading transients independently of such external triggers. The volumetric survey speed of the Zwicky Transient Facility (ZTF) makes it sensitive to objects as faint and fast fading as kilonovae, the optical counterparts to binary neutron star mergers, out to almost 200 Mpc. We introduce an open-source software infrastructure, the ZTF REaltime Search and Triggering, ZTFReST , designed to identify kilonovae and fast transients in ZTF data. Using the ZTF alert stream combined with forced point-spread-function photometry, we have implemented automated candidate ranking based on their photometric evolution and fitting to kilonova models. Automated triggering, with a human in the loop for monitoring, of follow-up systems has also been implemented. In 13 months of science validation, we found several extragalactic fast transients independently of any external trigger, including two supernovae with post-shock cooling emission, two known afterglows with an associated gamma-ray burst (ZTF20abbiixp, ZTF20abwysqy), two known afterglows without any known gamma-ray counterpart (ZTF20aajnksq, ZTF21aaeyldq), and three new fast-declining sources (ZTF20abtxwfx, ZTF20acozryr, ZTF21aagwbjr) that are likely associated with GRB200817A, GRB201103B, and GRB210204A. However, we have not found any objects that appear to be kilonovae. We constrain the rate of GW170817-like kilonovae to R < 900 Gpc
−3 yr−1 (95% confidence). A framework such as ZTFReST could become a prime tool for kilonova and fast-transient discovery with the Vera Rubin Observatory. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
27. A quantitative approach for measuring laterality in clinical fMRI for preoperative language mapping.
- Author
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Olaru, Maria, Nillo, Ryan M., Mukherjee, Pratik, and Sugrue, Leo P.
- Subjects
PREOPERATIVE care ,PHONOLOGICAL awareness ,MAGNETIC resonance imaging ,BRAIN mapping ,RETROSPECTIVE studies ,TASK performance ,QUANTITATIVE research ,CONCEPTUAL structures ,DESCRIPTIVE statistics - Abstract
Purpose: fMRI is increasingly used for presurgical language mapping, but lack of standard methodology has made it difficult to combine/compare data across institutions or determine the relative efficacy of different approaches. Here, we describe a quantitative analytic framework for determining language laterality in clinical fMRI that addresses these concerns. Methods: We retrospectively analyzed fMRI data from 59 patients who underwent presurgical language mapping at our institution with identical imaging and behavioral protocols. First, we compared the efficacy of different regional masks in capturing language activations. Then, we systematically explored how laterality indices (LIs) computed from these masks vary as a function of task and activation threshold. Finally, we determined the percentile threshold that maximized the correlation between the results of our LI approach and the laterality assessments from the original clinical radiology reports. Results: First, we found that a regional mask derived from a meta-analysis of the fMRI literature better captured language task activations than masks based on anatomically defined language areas. Then, we showed that an LI approach based on this functional mask and percentile thresholding of subject activation can quantify the relative ability of different language tasks to lateralize language function at the population level. Finally, we determined that the 92nd percentile of subject-level activation provides the optimal LI threshold with which to reproduce the original clinical reports. Conclusion: A quantitative framework for determining language laterality that uses a functionally-derived language mask and percentile thresholding of subject activation can combine/compare results across tasks and patients and reproduce clinical assessments of language laterality. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
28. Discovery and confirmation of the shortest gamma-ray burst from a collapsar.
- Author
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Ahumada, Tomás, Singer, Leo P., Anand, Shreya, Coughlin, Michael W., Kasliwal, Mansi M., Ryan, Geoffrey, Andreoni, Igor, Cenko, S. Bradley, Fremling, Christoffer, Kumar, Harsh, Pang, Peter T. H., Burns, Eric, Cunningham, Virginia, Dichiara, Simone, Dietrich, Tim, Svinkin, Dmitry S., Almualla, Mouza, Castro-Tirado, Alberto J., De, Kishalay, and Dunwoody, Rachel
- Published
- 2021
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29. Single‐Shot Fabrication of Semiconducting–Superconducting Nanowire Devices.
- Author
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Borsoi, Francesco, Mazur, Grzegorz P., van Loo, Nick, Nowak, Michał P., Bourdet, Léo, Li, Kongyi, Korneychuk, Svetlana, Fursina, Alexandra, Wang, Ji‐Yin, Levajac, Vukan, Memisevic, Elvedin, Badawy, Ghada, Gazibegovic, Sasa, van Hoogdalem, Kevin, Bakkers, Erik P. A. M., Kouwenhoven, Leo P., Heedt, Sebastian, and Quintero‐Pérez, Marina
- Subjects
NANOWIRE devices ,QUANTUM computing ,MAJORANA fermions ,NANOELECTROMECHANICAL systems ,NANOWIRES ,SEMICONDUCTOR synthesis ,SUPERCONDUCTORS - Abstract
Semiconducting–superconducting hybrids are vital components for the realization of high‐performance nanoscale devices. In particular, semiconducting–superconducting nanowires attract widespread interest owing to the possible presence of non‐abelian Majorana zero modes, which are quasiparticles that hold promise for topological quantum computing. However, systematic search for Majoranas signatures is challenging because it requires reproducible hybrid devices and reliable fabrication methods. This work introduces a fabrication concept based on shadow walls that enables the in situ, selective, and consecutive depositions of superconductors and normal metals to form normal‐superconducting junctions. Crucially, this method allows to realize devices in a single shot, eliminating fabrication steps after the synthesis of the fragile semiconductor/superconductor interface. At the atomic level, all investigated devices reveal a sharp and defect‐free semiconducting–superconducting interface and, correspondingly, a hard induced superconducting gap resilient up to 2 T is measured electrically. While the cleanliness of the technique enables systematic studies of topological superconductivity in nanowires, it also allows for the synthesis of advanced nano‐devices based on a wide range of material combinations and geometries while maintaining an exceptionally high interface quality. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
30. Shadow-wall lithography of ballistic superconductor–semiconductor quantum devices.
- Author
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Heedt, Sebastian, Quintero-Pérez, Marina, Borsoi, Francesco, Fursina, Alexandra, van Loo, Nick, Mazur, Grzegorz P., Nowak, Michał P., Ammerlaan, Mark, Li, Kongyi, Korneychuk, Svetlana, Shen, Jie, van de Poll, May An Y., Badawy, Ghada, Gazibegovic, Sasa, de Jong, Nick, Aseev, Pavel, van Hoogdalem, Kevin, Bakkers, Erik P. A. M., and Kouwenhoven, Leo P.
- Subjects
SEMICONDUCTOR nanowires ,LITHOGRAPHY ,JOSEPHSON junctions ,ANDREEV reflection ,MAGNETIC fields ,NANOWIRES ,SILICON nanowires - Abstract
The realization of hybrid superconductor–semiconductor quantum devices, in particular a topological qubit, calls for advanced techniques to readily and reproducibly engineer induced superconductivity in semiconductor nanowires. Here, we introduce an on-chip fabrication paradigm based on shadow walls that offers substantial advances in device quality and reproducibility. It allows for the implementation of hybrid quantum devices and ultimately topological qubits while eliminating fabrication steps such as lithography and etching. This is critical to preserve the integrity and homogeneity of the fragile hybrid interfaces. The approach simplifies the reproducible fabrication of devices with a hard induced superconducting gap and ballistic normal-/superconductor junctions. Large gate-tunable supercurrents and high-order multiple Andreev reflections manifest the exceptional coherence of the resulting nanowire Josephson junctions. Our approach enables the realization of 3-terminal devices, where zero-bias conductance peaks emerge in a magnetic field concurrently at both boundaries of the one-dimensional hybrids. Advanced fabrication techniques enable a wide range of quantum devices, such as the realization of a topological qubit. Here, the authors introduce an on-chip fabrication technique based on shadow walls to implement topological qubits in an InSb nanowire without fabrication steps such as lithography and etching. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
31. High-Precision Complementary Metamaterial Sensor Using Slotted Microstrip Transmission Line.
- Author
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Samad, Abdul, Hu, Wei Dong, Shahzad, Waseem, Ligthart, Leo. P., and Raza, Hamid
- Subjects
MICROSTRIP transmission lines ,DIELECTRIC measurements ,MICROSTRIP filters ,DIELECTRIC materials ,PERMITTIVITY ,DIELECTRIC properties ,MICROWAVE filters - Abstract
Metamaterial-based microwave sensor having novel and compact structure of the resonators and the slotted microstrip transmission line is proposed for highly precise measurement of dielectric properties of the materials under test (MUTs). The proposed sensor is designed and simulated on Rogers' substrate RO4003C by using the ANSYS HFSS software. A single and accumulative notch depth of -44.29 dB in the transmission coefficient ( S 21 ) is achieved at the resonant frequency of 5.15 GHz. The negative constitutive parameters (permittivity and permeability) are extracted from the S -parameters which are the basic property of metamaterials or left handed materials (LHMs). The proposed sensor is fabricated and measured through the PNA-X (N5247A). The sensitivity analysis is performed by placing various standard dielectric materials onto the sensor and measuring the shift in the resonant frequencies of the MUTs. A parabolic equation of the proposed sensor is formulated to approximate the resonant frequency and the relative permittivity of the MUTs. A very strong agreement among the simulated, measured, and calculated results is found which reveals that the proposed sensor is a highly precise sensor for the characterization of dielectric properties of the MUTs. Error analysis is performed to determine the accuracy of the proposed sensor. A very small percentage of error (0.81%) and a very low standard deviation are obtained which indicate high accuracy of the proposed sensor. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
32. Catheter directed thrombolysis and mechanical intervention in deep venous thrombosis: What is the status after the ATTRACT Trial?
- Author
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Fletcher, Savannah E., Jasuja, Sonia, Lawler, Leo P., and Moriarty, John M.
- Abstract
Deep venous thrombosis (DVT) is a major cause of acute and chronic morbidity, mortality, and increased healthcare costs. Endovascular methods for thrombus removal and reestablishing venous patency are increasing in both scope and usage. The most commonly used method for endovascular thrombectomy is catheter-directed thrombolysis (CDT). Several studies have shown promise for CDT in alleviating acute symptomatology in acute lower extremity DVT as well as mitigating potential long-term consequences of DVT, such as post-thrombotic syndrome (PTS). The Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis (ATTRACT) trial is the largest and most comprehensive randomized-controlled trial to date evaluating CDT compared to anticoagulation alone for the treatment of acute symptomatic proximal lower extremity DVT. This review discusses the current status of CDT and adjunctive endovascular interventions for DVT, particularly in the context of the ATTRACT trial. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
33. A framework infrageneric classification of Carex (Cyperaceae) and its organizing principles.
- Author
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Roalson, Eric H., Jiménez‐Mejías, Pedro, Hipp, Andrew L., Benítez‐Benítez, Carmen, Bruederle, Leo P., Chung, Kyong‐Sook, Escudero, Marcial, Ford, Bruce A., Ford, Kerry, Gebauer, Sebastian, Gehrke, Berit, Hahn, Marlene, Hayat, Muhammad Qasim, Hoffmann, Mathias H., Jin, Xiao‐Feng, Kim, Sangtae, Larridon, Isabel, Léveillé‐Bourret, Étienne, Lu, Yi‐Fei, and Luceño, Modesto
- Subjects
CYPERACEAE ,CYPERUS ,LINEAR orderings ,CLASSIFICATION ,TAXONOMISTS - Abstract
Phylogenetic studies of Carex L. (Cyperaceae) have consistently demonstrated that most subgenera and sections are para‐ or polyphyletic. Yet, taxonomists continue to use subgenera and sections in Carex classification. Why? The Global Carex Group (GCG) here takes the position that the historical and continued use of subgenera and sections serves to (i) organize our understanding of lineages in Carex, (ii) create an identification mechanism to break the ~2000 species of Carex into manageable groups and stimulate its study, and (iii) provide a framework to recognize morphologically diagnosable lineages within Carex. Unfortunately, the current understanding of phylogenetic relationships in Carex is not yet sufficient for a global reclassification of the genus within a Linnean infrageneric (sectional) framework. Rather than leaving Carex classification in its current state, which is misleading and confusing, we here take the intermediate steps of implementing the recently revised subgeneric classification and using a combination of informally named clades and formally named sections to reflect the current state of our knowledge. This hybrid classification framework is presented in an order corresponding to a linear arrangement of the clades on a ladderized phylogeny, largely based on the recent phylogenies published by the GCG. It organizes Carex into six subgenera, which are, in turn, subdivided into 62 formally named Linnean sections plus 49 informal groups. This framework will serve as a roadmap for research on Carex phylogeny, enabling further development of a complete reclassification by presenting relevant morphological and geographical information on clades where possible and standardizing the use of formal sectional names. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
34. Optimizing serendipitous detections of kilonovae: cadence and filter selection.
- Author
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Almualla, Mouza, Anand, Shreya, Coughlin, Michael W, Dietrich, Tim, Guessoum, Nidhal, Sagués Carracedo, Ana, Ahumada, Tomás, Andreoni, Igor, Antier, Sarah, Bellm, Eric C, Bulla, Mattia, and Singer, Leo P
- Subjects
GAMMA ray bursts ,STELLAR mergers ,ASTRONOMY ,NEUTRON stars - Abstract
The rise of multimessenger astronomy has brought with it the need to exploit all available data streams and learn more about the astrophysical objects that fall within its breadth. One possible avenue is the search for serendipitous optical/near-infrared counterparts of gamma-ray bursts (GRBs) and gravitational-wave (GW) signals, known as kilonovae. With surveys such as the Zwicky Transient Facility (ZTF), which observes the sky with a cadence of ∼3 d, the existing counterpart locations are likely to be observed; however, due to the significant amount of sky to explore, it is difficult to search for these fast-evolving candidates. Thus, it is beneficial to optimize the survey cadence for realtime kilonova identification and enable further photometric and spectroscopic observations. We explore how the cadence of wide field-of-view surveys like ZTF can be improved to facilitate such identifications. We show that with improved observational choices, e.g. the adoption of three epochs per night on a ∼ nightly basis, and the prioritization of redder photometric bands, detection efficiencies improve by about a factor of two relative to the nominal cadence. We also provide realistic hypothetical constraints on the kilonova rate as a form of comparison between strategies, assuming that no kilonovae are detected throughout the long-term execution of the respective observing plan. These results demonstrate how an optimal use of ZTF increases the likelihood of kilonova discovery independent of GWs or GRBs, thereby allowing for a sensitive search with less interruption of its nominal cadence through Target of Opportunity programs. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
35. Rates of Incidental Findings in Brain Magnetic Resonance Imaging in Children.
- Author
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Li, Yi, Thompson, Wesley K., Reuter, Chase, Nillo, Ryan, Jernigan, Terry, Dale, Anders, Sugrue, Leo P., Brown, Julian, Dougherty, Robert F., Rauschecker, Andreas, Rudie, Jeffrey, Barch, Deanna M., Calhoun, Vince, Hagler, Donald, Hatton, Sean, Tanabe, Jody, Marshall, Andrew, Sher, Kenneth J., Heeringa, Steven, and Hermosillo, Robert
- Published
- 2021
- Full Text
- View/download PDF
36. Phenotyping chlorogenic acids and coumarins in sweet potato [Ipomoea batatas (L.) Lam.] breeding lines for enhanced tolerance to periderm pathogens.
- Author
-
Lebot, V., Leo, P., and Legendre, L.
- Subjects
SWEET potatoes ,CHLOROGENIC acid ,COUMARINS ,INSECT baits & repellents ,SCOPOLETIN ,PHENOTYPES - Abstract
Genetic improvement of sweet potato [Ipomoea batatas (L.) Lam.] is based on recurrent cycles of phenotypic selection and recombination of parents. Metabolite profiling can be used to differentiate chemotypes to assist selection of parents. Chlorogenic acids (CQAs) and coumarins are natural fungicides and insect repellents present in the storage root periderm which can contribute to reduction of post-harvest losses and insect damage. The objectives of this study were: (i) to develop a rapid and reliable analytical technique for screening breeding lines, (ii) to correlate their CQAs and coumarins contents with periderm colour and biotic stress susceptibility, and (iii) to assess variation among clones. A first experiment measured the variation in scopolin, scopoletin, chlorogenic acid (CGA) and three dicaffeoylquinic acids (3,4-, 4,5-, 3,5-diCQA) in 296 breeding lines periderm. CGA (mean of 0.95 µg/mg FW) and 3,5-diCQA (0.86 µg/mg) contents were significantly higher than scopolin (0.50 µg/mg), scopoletin (0.09 µg/mg), 3,4-diCQA (0.09 µg/mg), and 4,5-diCQA (0.16 µg/mg). CGA was significantly and positively correlated with all compounds but especially with 3,5-diCQA (+ 0.812**). All compounds were in significantly higher content in purple-red periderm breeding lines. A second experiment estimated the range of variation among five clones for 39 selected breeding lines. The results confirmed the first experiment. Furthermore, for all six compounds the coefficient of variation in the second experiment were low indicating that they are genetically controlled. CQAs appear to be more interesting compounds compared to coumarins for selecting breeding lines and chemotype assisted breeding should be a useful tool to reduce post-harvest losses and insect damage. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
37. High genomic diversity maintained by populations of Carex scirpoidea subsp. convoluta, a paraphyletic Great Lakes ecotype.
- Author
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Bard, Nicholas W., Miller, Christopher S., and Bruederle, Leo P.
- Subjects
HABITAT conservation ,ICE sheets ,GENOMICS ,BAYESIAN analysis ,LAKES - Abstract
Range-limited endemic taxa are threatened by loss of genomic diversity, which can lead to extirpation and extinction. The imperiled and narrowly distributed edaphic endemic Carex scirpoidea subsp. convoluta (Cyperaceae), which is primarily limited to alvar soils on the northern shores of Lake Huron in North America, exhibits such risk. In contrast, the conspecific C. scirpoidea subsp. scirpoidea is widely distributed across a vast geographical range and occupies various arctic and alpine habitat types. Using ddRADseq, population genomic analyses of 11 North American populations of C. scirpoidea including five subsp. convoluta populations revealed similar-to-higher levels of genomic diversity in the latter compared to its more widely distributed conspecific subsp. scirpoidea. Dioecy and a nearly obligate outcrossing mode of reproduction have likely contributed to the maintenance of genomic diversity in subsp. convoluta, preventing inbreeding depression, and contributing to the evolutionary potential of populations of this taxon. Phylogenomic and Bayesian analyses of ddRADseq data revealed that subsp. convoluta is paraphyletic with Eastern North American subsp. scirpoidea populations, suggesting that it best be considered a locally adapted ecotype. Furthermore, Eastern North America populations of both taxa arose from populations that likely occupied periglacial refugia south of the Laurentide Ice Sheet, where they no longer occur. Herein, we identify conservation units among the sampled Eastern North American C. scirpoidea populations to aid management efforts, which we suggest should include habitat protection and replanting for habitat restoration purposes. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
38. Halonium Catalysis: An Underutilized and Underexplored Catalytic Concept in Olefin Functionalizations.
- Author
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Gembreska, Nathan R., Vogel, Alexander K., Ziegelmeyer, Elizabeth C., Cheng, Eric, Wu, Fan, Roberts, Leo P., Vesoulis, Megan M., and Li, Wei
- Subjects
CATALYSIS ,CONCEPTS ,UREA ,HYPOTHESIS ,ALKENES - Abstract
Iodonium catalysis is described here to accomplish an intermolecular olefin oxyamination reaction. Urea is used as the O- and N-source to add across both activated and unactivated alkenes in a regioselective manner. Mechanistic studies confirm the presence of an iodonium intermediate. 1 Introduction 2 Hypothesis 3 Optimizations and Scope 4 Mechanistic Probes 5 Future Outlook [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
39. FMCW radar antenna using a half parabolic reflector with microstrip-patch-array offset feed and tuning strip.
- Author
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Lestari, Andrian Andaya and Ligthart, Leo P.
- Subjects
RADAR antennas ,PARABOLIC reflectors ,REFLECTOR antennas ,RECEIVING antennas ,TRANSMITTING antennas - Abstract
In this paper, we propose a reflector antenna with a microstrip-patch-array offset feed. The proposed antenna offers several advantages in design flexibility, especially to determine the horizontal and vertical beam patterns by the modular feed and the reflector curvature design, respectively. Moreover, it provides an internal tuning mechanism in the form of a tuning strip which is relatively simple to apply. The paper describes the steps in a parametric study carried out to minimize the antenna dimensions. The resulting optimized design is found to be around 50% smaller in dimension than the initial design of the proposed antenna. A demonstrator for experimental analysis, consisting of a transmit and a receive antenna, has been constructed, and the isolation between the antennas is found to be better than 70 dB. The antenna demonstrator has been integrated with an FMCW radar transceiver and satisfactorily tested to operate as a coastal surveillance radar. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
40. Optical follow-up of the neutron star–black hole mergers S200105ae and S200115j.
- Author
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Anand, Shreya, Coughlin, Michael W., Kasliwal, Mansi M., Bulla, Mattia, Ahumada, Tomás, Sagués Carracedo, Ana, Almualla, Mouza, Andreoni, Igor, Stein, Robert, Foucart, Francois, Singer, Leo P., Sollerman, Jesper, Bellm, Eric C., Bolin, Bryce, Caballero-García, M. D., Castro-Tirado, Alberto J., Cenko, S. Bradley, De, Kishalay, Dekany, Richard G., and Duev, Dmitry A.
- Published
- 2021
- Full Text
- View/download PDF
41. Artificial intelligence in eye care.
- Author
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Semes, Leo P.
- Subjects
DIABETIC retinopathy ,ARTIFICIAL intelligence ,EYE care ,VISION testing ,RETINAL diseases ,WATSON (Computer) ,SLIT lamp microscopy - Published
- 2023
42. ZTF20aajnksq (AT 2020blt): A Fast Optical Transient at z ≈ 2.9 with No Detected Gamma-Ray Burst Counterpart.
- Author
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Ho, Anna Y. Q., Perley, Daniel A., Beniamini, Paz, Cenko, S. Bradley, Kulkarni, S. R., Andreoni, Igor, Singer, Leo P., De, Kishalay, Kasliwal, Mansi M., Fremling, Christoffer, Bellm, Eric C., Dekany, Richard, Delacroix, Alexandre, Duev, Dmitry A., Goldstein, Daniel A., Golkhou, V. Zach, Goobar, Ariel, Graham, Matthew J., Hale, David, and Kupfer, Thomas
- Subjects
GAMMA ray bursts ,LIGHT curves ,REDSHIFT ,X-rays - Abstract
We present ZTF20aajnksq (AT 2020blt), a fast-fading (Δr = 2.3 mag in Δt = 1.3 days) red (g − r ≈ 0.6 mag) and luminous (M
1626 Å = −25.9 mag) optical transient at z = 2.9 discovered by the Zwicky Transient Facility (ZTF). AT 2020blt shares several features in common with afterglows to long-duration gamma-ray bursts (GRBs): (1) an optical light curve well-described by a broken power law with a break at tj = 1 d (observer frame); (2) a luminous (L0.3–10 KeV = 1046 erg s−1 ) X-ray counterpart; and (3) luminous (L10 GHz = 4 × 1031 erg s−1 Hz−1 ) radio emission. However, no GRB was detected in the 0.74 days between the last ZTF nondetection (r > 21.36 mag) and the first ZTF detection (r = 19.60 mag), with an upper limit on the isotropic-equivalent gamma-ray energy release of Eγ,iso < 7 × 1052 erg. AT 2020blt is thus the third afterglow-like transient discovered without a detected GRB counterpart (after PTF11agg and ZTF19abvizsw) and the second (after ZTF19abvizsw) with a redshift measurement. We conclude that the properties of AT 2020blt are consistent with a classical (initial Lorentz factor Γ0 ≳ 100) on-axis GRB that was missed by high-energy satellites. Furthermore, by estimating the rate of transients with light curves similar to that of AT 2020blt in ZTF high-cadence data, we agree with previous results that there is no evidence for an afterglow-like phenomenon that is significantly more common than classical GRBs, such as dirty fireballs. We conclude by discussing the status and future of fast-transient searches in wide-field high-cadence optical surveys. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
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43. Kilonova Luminosity Function Constraints Based on Zwicky Transient Facility Searches for 13 Neutron Star Merger Triggers during O3.
- Author
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Kasliwal, Mansi M., Anand, Shreya, Ahumada, Tomás, Stein, Robert, Carracedo, Ana Sagués, Andreoni, Igor, Coughlin, Michael W., Singer, Leo P., Kool, Erik C., De, Kishalay, Kumar, Harsh, AlMualla, Mouza, Yao, Yuhan, Bulla, Mattia, Dobie, Dougal, Reusch, Simeon, Perley, Daniel A., Cenko, S. Bradley, Bhalerao, Varun, and Kaplan, David L.
- Subjects
STELLAR mergers ,LUMINOSITY ,BLACK holes ,GRAVITATIONAL waves ,BINARY stars ,RADIO telescopes ,NEUTRON stars ,BINARY black holes - Abstract
We present a systematic search for optical counterparts to 13 gravitational wave (GW) triggers involving at least one neutron star during LIGO/Virgo's third observing run (O3). We searched binary neutron star (BNS) and neutron star black hole (NSBH) merger localizations with the Zwicky Transient Facility (ZTF) and undertook follow-up with the Global Relay of Observatories Watching Transients Happen (GROWTH) collaboration. The GW triggers had a median localization area of 4480 deg
2 , a median distance of 267 Mpc, and false-alarm rates ranging from 1.5 to 10−25 yr−1 . The ZTF coverage in the g and r bands had a median enclosed probability of 39%, median depth of 20.8 mag, and median time lag between merger and the start of observations of 1.5 hr. The O3 follow-up by the GROWTH team comprised 340 UltraViolet/Optical/InfraRed (UVOIR) photometric points, 64 OIR spectra, and three radio images using 17 different telescopes. We find no promising kilonovae (radioactivity-powered counterparts), and we show how to convert the upper limits to constrain the underlying kilonova luminosity function. Initially, we assume that all GW triggers are bona fide astrophysical events regardless of false-alarm rate and that kilonovae accompanying BNS and NSBH mergers are drawn from a common population; later, we relax these assumptions. Assuming that all kilonovae are at least as luminous as the discovery magnitude of GW170817 (−16.1 mag), we calculate that our joint probability of detecting zero kilonovae is only 4.2%. If we assume that all kilonovae are brighter than −16.6 mag (the extrapolated peak magnitude of GW170817) and fade at a rate of 1 mag day−1 (similar to GW170817), the joint probability of zero detections is 7%. If we separate the NSBH and BNS populations based on the online classifications, the joint probability of zero detections, assuming all kilonovae are brighter than −16.6 mag, is 9.7% for NSBH and 7.9% for BNS mergers. Moreover, no more than <57% (<89%) of putative kilonovae could be brighter than −16.6 mag assuming flat evolution (fading by 1 mag day−1 ) at the 90% confidence level. If we further take into account the online terrestrial probability for each GW trigger, we find that no more than <68% of putative kilonovae could be brighter than −16.6 mag. Comparing to model grids, we find that some kilonovae must have Mej < 0.03 M⊙ , Xlan > 10−4 , or ϕ > 30° to be consistent with our limits. We look forward to searches in the fourth GW observing run; even 17 neutron star mergers with only 50% coverage to a depth of −16 mag would constrain the maximum fraction of bright kilonovae to <25%. [ABSTRACT FROM AUTHOR]- Published
- 2020
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44. Design of highly sensitive complementary metamaterial‐based microwave sensor for characterisation of dielectric materials.
- Author
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Samad, Abdul, Hu, Wei Dong, Shahzad, Waseem, Raza, Hamid, and Ligthart, Leo P.
- Abstract
Metamaterial‐based double‐slit complementary split rectangular resonator sensor is proposed for the characterisation of dielectric properties of the materials under test (MUTs). The proposed sensor is designed and simulated on the CST microwave studio software using a low‐cost substrate FR4. An array of three identical resonators is etched in the ground plane of the sensor to achieve a single and deep notch of −58.7 dB in the transmission coefficient (S21) at the resonant frequency of 7.01 GHz, which is the novelty of the proposed sensor. A deep and single resonant frequency band has a significant role in the precise measurement of the dielectric properties of the MUTs. The effective constitutive parameters are extracted from the S‐parameters. An equivalent circuit model is suggested that describes the overall behaviour of the sensor. The sensor is fabricated on the FR4 substrate and measured through the vector network analyser (N5224B) by placing the standard materials. The parabolic equation for the proposed sensor is formulated to approximate the permittivity of the MUTs. A very small percentage of error, 0.77, is found which shows high accuracy of the sensor. This methodology is efficient, simple in fabrication, and reduces cost and computational time also. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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- View/download PDF
45. Gray Matter Changes in Adolescents Participating in a Meditation Training.
- Author
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Yuan, Justin P., Connolly, Colm G., Henje, Eva, Sugrue, Leo P., Yang, Tony T., Xu, Duan, and Tymofiyeva, Olga
- Subjects
TEENAGERS ,MEDITATION ,VOXEL-based morphometry ,MAGNETIC resonance imaging ,BRAIN imaging - Abstract
Meditation has shown to benefit a wide range of conditions and symptoms, but the neural mechanisms underlying the practice remain unclear. Magnetic resonance imaging (MRI) studies have investigated the structural brain changes due to the practice by examining volume, density, or cortical thickness changes. However, these studies have focused on adults; meditation's structural effects on the adolescent brain remain understudied. In this study, we investigated how meditation training affects the structure of the adolescent brain by scanning a group of 38 adolescents (16.48 ± 1.29 years) before and after participating in a 12-week meditation training. Subjects underwent Training for Awareness, Resilience, and Action (TARA), a program that mainly incorporates elements from mindfulness meditation and yoga-based practices. A subset of the adolescents also received an additional control scan 12 weeks before TARA. We conducted voxel-based morphometry (VBM) to assess gray matter volume changes pre- to post-training and during the control period. Subjects showed significant gray matter (GM) volume decreases in the left posterior insula and to a lesser extent in the left thalamus and left putamen after meditation training. There were no significant changes during the control period. Our results support previous findings that meditation affects regions associated with physical and emotional awareness. However, our results are different from previous morphometric studies in which meditation was associated with structural increases. We posit that this discrepancy may be due to the differences between the adolescent brain and the adult brain. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
46. Transmission phase read-out of a large quantum dot in a nanowire interferometer.
- Author
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Borsoi, Francesco, Zuo, Kun, Gazibegovic, Sasa, Op het Veld, Roy L. M., Bakkers, Erik P. A. M., Kouwenhoven, Leo P., and Heedt, Sebastian
- Subjects
QUANTUM dots ,FANO resonance ,RESONANT tunneling ,INTERFEROMETERS ,NANOWIRES ,ELECTRON transport ,NANOWIRE devices ,QUBITS - Abstract
Detecting the transmission phase of a quantum dot via interferometry can reveal the symmetry of the orbitals and details of electron transport. Crucially, interferometry will enable the read-out of topological qubits based on one-dimensional nanowires. However, measuring the transmission phase of a quantum dot in a nanowire has not yet been established. Here, we exploit recent breakthroughs in the growth of one-dimensional networks and demonstrate interferometric read-out in a nanowire-based architecture. In our two-path interferometer, we define a quantum dot in one branch and use the other path as a reference arm. We observe Fano resonances stemming from the interference between electrons that travel through the reference arm and undergo resonant tunnelling in the quantum dot. Between consecutive Fano peaks, the transmission phase exhibits phase lapses that are affected by the presence of multiple trajectories in the interferometer. These results provide critical insights for the design of future topological qubits. Measuring the transmission phase of a quantum dot is crucial for the read-out of future topological qubits based on nanowire networks but has not been established yet. Here, the authors demonstrate interferometric read-out of the transmission phase in a nanowire-based architecture. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
47. Dynamic scheduling: target of opportunity observations of gravitational wave events.
- Author
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Almualla, Mouza, Coughlin, Michael W, Anand, Shreya, Alqassimi, Khalid, Guessoum, Nidhal, and Singer, Leo P
- Subjects
GRAVITATIONAL waves ,VERY large array telescopes ,SCHEDULING ,ELECTROMAGNETIC waves ,NEUTRON stars - Abstract
The simultaneous detection of electromagnetic and gravitational waves from the coalescence of two neutron stars (GW170817 and GRB170817A) has ushered in a new era of 'multimessenger' astronomy, with electromagnetic detections spanning from gamma to radio. This great opportunity for new scientific investigations raises the issue of how the available multimessenger tools can best be integrated to constitute a powerful method to study the transient Universe in particular. To facilitate the classification of possible optical counterparts to gravitational wave events, it is important to optimize the scheduling of observations and the filtering of transients, both key elements of the follow-up process. In this work, we describe the existing workflow whereby telescope networks such as GRANDMA and GROWTH are currently scheduled; we then present modifications we have developed for the scheduling process specifically, so as to face the relevant challenges that have appeared during the latest observing run of Advanced LIGO and Advanced Virgo. We address issues with scheduling more than one epoch for multiple fields within a skymap, especially for large and disjointed localizations. This is done in two ways: by optimizing the maximum number of fields that can be scheduled and by splitting up the lobes within the skymap by right ascension to be scheduled individually. In addition, we implement the ability to take previously observed fields into consideration when rescheduling. We show the improvements that these modifications produce in making the search for optical counterparts more efficient, and we point to areas needing further improvement. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
48. Can One-Run-Fixed-Arrhenius Kerogen Analysis Provide Comparable Organofacies Results to Detailed Palynological Analysis? A Case Study from a Prospective Mississippian Source Rock Reservoir (Bowland Shale, UK).
- Author
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Newport, Sarah M., Hennissen, Jan A. I., Armstrong, James P., Taylor, Kevin G., Newport, Leo P., and Hough, Edward
- Subjects
ORGANIC geochemistry ,KEROGEN ,RESERVOIR rocks ,ROCK slopes ,SHALE ,LITHOFACIES ,LONGITUDINAL method - Abstract
Organofacies analysis, a fundamental component within source rock appraisal based on the study of kerogen within a source rock, is typically produced from microscopy (palynological) and geochemical (kerogen kinetic) data, both of which are costly to acquire. One-Run-Fixed-Arrhenius (ORFA) kerogen kinetic analysis based on Rock–Eval pyrolysis offers a substantially cheaper kinetic dataset. Here, ORFA and palynological analyses are compared in organofacies characterization of a prospective Mississippian source rock reservoir (Bowland Shale, UK). Two-end-member organofacies were determined based on the abundance of the 56 kcal/mol activation energy peak derived from ORFA data: absence (< 5%) indicating 'organofacies A' containing the highest proportion of algal material (Type I kerogen); and presence (> 15%) indicating 'organofacies B' containing the highest proportion of sporomorphs (Type II kerogen). A mud-dominated slope setting for the rock reservoir was also used to test the accuracy of organofacies analysis in determining depositional environment. Organofacies A found within lithofacies deposited from dilute waning density flows and hemipelagic suspension settling occurred between shelf edge, slope and basin. Organofacies B found within lithofacies deposited from dilute waning density flows, and low-strength cohesive debrites occurred only within the lower slope. This study demonstrates that ORFA kerogen kinetic analysis provides comparable net results to palynological analysis, enabling cheaper and faster organic characterization during initial source rock appraisal. However, caution must be exercised in drawing interpretations as to biological source(s), organic matter mixing and preservation state(s) without additional investigation using data from detailed palynological analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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- View/download PDF
49. Majorana qubits for topological quantum computing.
- Author
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Aguado, Ramón and Kouwenhoven, Leo P.
- Subjects
QUBITS ,MAJORANA fermions ,QUANTUM gates ,QUANTUM computing - Abstract
Researchers are trying to store robust quantum information in Majorana particles and are generating quantum gates by exploiting the bizarre non-abelian statistics of Majorana zero modes bound to topological defects. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
50. Measurement of bronchial hyperreactivity: comparison of three Nordic dosimetric methods.
- Author
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Lassmann-Klee, Paul G., Sundblad, Britt-Marie, Malmberg, Leo P., Sovijärvi, Anssi R. A., and Piirilä, Päivi
- Subjects
BRONCHIAL spasm ,RADIATION dosimetry ,ASTHMA diagnosis ,FORCED expiratory volume ,EPIDEMIOLOGICAL research ,BRONCHIAL disease diagnosis ,RESEARCH ,ASTHMA ,RESEARCH methodology ,METHACHOLINE chloride ,CASE-control method ,MEDICAL cooperation ,EVALUATION research ,COMPARATIVE studies ,BRONCHIAL provocation tests ,DOSE-effect relationship in pharmacology ,SPIROMETRY ,HISTAMINE ,BRONCHIAL diseases ,LONGITUDINAL method - Abstract
Clinical testing of bronchial hyperreactivity (BHR) provides valuable information in asthma diagnostics. Nevertheless, the test results depend to a great extent on the testing procedure: test substance, apparatus and protocol. In Nordic countries, three protocols predominate in the testing field: Per Malmberg, Nieminen and Sovijärvi methods. However, knowledge of their equivalence is limited. We aimed to find equivalent provocative doses (PD) to obtain similar bronchoconstrictive responses for the three protocols. We recruited 31 patients with suspected asthma and health care workers and performed BHR testing with methacholine according to Malmberg and Nieminen methods, and with histamine according to Sovijärvi. We obtained the individual response-dose slopes for each method and predicted equivalent PD values. Applying a mixed-model, we found significant differences in the mean (standard error of mean) response-dose (forced expiratory volume in one second (FEV1)%/mg): Sovijärvi 7.2 (1.5), Nieminen 13.8 (4.2) and Malmberg 26 (7.3). We found that the earlier reported cut-point values for moderate BHR and marked BHR between the Sovijärvi (PD15) and Nieminen (PD20) methods were similar, but with the Malmberg method a significant bronchoconstrictive reaction was measured with lower PD20 values. We obtained a relationship between slope values and PD (mg) between different methods, useful in epidemiological research and clinical practice. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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