3,141 results on '"Armand M"'
Search Results
2. Microvesicle-Mediated Tissue Regeneration Mitigates the Effects of Cellular Ageing
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Nikolaos Panagiotou, Dagmara McGuinness, Armand M. G. Jaminon, Barend Mees, Colin Selman, Leon Schurgers, and Paul G. Shiels
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ageing ,regenerative medicine ,stem cells ,extracellular vesicles ,microvesicles ,exosomes ,Cytology ,QH573-671 - Abstract
Extracellular vesicles (EVs), comprising microvesicles (MVs) and exosomes (Exos), are membranous vesicles secreted by cells which mediate the repair of cellular and tissue damage via paracrine mechanisms. The action of EVs under normative and morbid conditions in the context of ageing remains largely unexplored. We demonstrate that MVs, but not Exos, from Pathfinder cells (PCs), a putative stem cell regulatory cell type, enhance the repair of human dermal fibroblast (HDF) and mesenchymal stem cell (MSC) co-cultures, following both mechanical and genotoxic stress. Critically, this effect was found to be both cellular age and stress specific. Notably, MV treatment was unable to repair mechanical injury in older co-cultures but remained therapeutic following genotoxic stress. These observations were further confirmed in human dermal fibroblast (HDF) and vascular smooth muscle cell (VSMC) co-cultures of increasing cellular age. In a model of comorbidity comprising co-cultures of HDFs and highly senescent abdominal aortic aneurysm (AAA) VSMCs, MV administration appeared to be senotherapeutic, following both mechanical and genotoxic stress. Our data provide insights into EVs and the specific roles they play during tissue repair and ageing. These data will potentiate the development of novel cell-free therapeutic interventions capable of attenuating age-associated morbidities and avoiding undesired effects.
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- 2023
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3. A food web including parasites for kelp forests of the Santa Barbara Channel, California
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Dana N. Morton, Cristiana Y. Antonino, Farallon J. Broughton, Lauren N. Dykman, Armand M. Kuris, and Kevin D. Lafferty
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Science - Abstract
Measurement(s) Host-Parasite Relationship • food web • ecological community Technology Type(s) Dissection • digestive tract environment • digital curation Sample Characteristic - Organism Vertebrata • Platyhelminthes • Arthropoda • Mollusca • Macrocystis pyrifera Sample Characteristic - Environment kelp forest Sample Characteristic - Location Santa Barbara Channel Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.13487178
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- 2021
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4. High parasite diversity in the amphipod Gammarus lacustris in a subarctic lake
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Jenny C. Shaw, Eirik H. Henriksen, Rune Knudsen, Jesper A. Kuhn, Armand M. Kuris, Kevin D. Lafferty, Anna Siwertsson, Miroslava Soldánová, and Per‐Arne Amundsen
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Amphipod ,Cestoda ,food web ,Trematoda ,trophically transmitted parasites ,Ecology ,QH540-549.5 - Abstract
Abstract Amphipods are often key species in aquatic food webs due to their functional roles in the ecosystem and as intermediate hosts for trophically transmitted parasites. Amphipods can also host many parasite species, yet few studies address the entire parasite community of a gammarid population, precluding a more dynamic understanding of the food web. We set out to identify and quantify the parasite community of Gammarus lacustris to understand the contributions of the amphipod and its parasites to the Takvatn food web. We identified seven parasite taxa: a direct life cycle gregarine, Rotundula sp., and larval stages of two digenean trematode genera, two cestodes, one nematode, and one acanthocephalan. The larval parasites use either birds or fishes as final hosts. Bird parasites predominated, with trematode Plagiorchis sp. having the highest prevalence (69%) and mean abundance (2.7). Fish parasites were also common, including trematodes Crepidostomum spp., nematode Cystidicola farionis, and cestode Cyathocephalus truncatus (prevalences 13, 6, and 3%, respectively). Five parasites depend entirely on G. lacustris to complete their life cycle. At least 11.4% of the overall parasite diversity in the lake was dependent on G. lacustris, and 16% of the helminth diversity required or used the amphipod in their life cycles. These dependencies reveal that in addition to being a key prey item in subarctic lakes, G. lacustris is also an important host for maintaining parasite diversity in such ecosystems.
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- 2020
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5. Improved Quantification of Cell Density in the Arterial Wall—A Novel Nucleus Splitting Approach Applied to 3D Two-Photon Laser-Scanning Microscopy
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Koen W. F. van der Laan, Koen D. Reesink, Myrthe M. van der Bruggen, Armand M. G. Jaminon, Leon J. Schurgers, Remco T. A. Megens, Wouter Huberts, Tammo Delhaas, and Bart Spronck
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cell content characterization ,image analysis ,nucleus segmentation ,spectral clustering ,cell density distribution ,vascular smooth muscle cell apoptosis ,Physiology ,QP1-981 - Abstract
Accurate information on vascular smooth muscle cell (VSMC) content, orientation, and distribution in blood vessels is indispensable to increase understanding of arterial remodeling and to improve modeling of vascular biomechanics. We have previously proposed an analysis method to automatically characterize VSMC orientation and transmural distribution in murine carotid arteries under well-controlled biomechanical conditions. However, coincident nuclei, erroneously detected as one large nucleus, were excluded from the analysis, hampering accurate VSMC content characterization and distorting transmural distributions. In the present study, therefore, we aim to (1) improve the previous method by adding a “nucleus splitting” procedure to split coinciding nuclei, (2) evaluate the accuracy of this novel method, and (3) test this method in a mouse model of VSMC apoptosis. After euthanasia, carotid arteries from SM22α-hDTR Apoe–/– and control Apoe–/– mice were bluntly dissected, excised, mounted in a biaxial biomechanical tester and brought to in vivo axial stretch and a pressure of 100 mmHg. Nuclei and elastin fibers were then stained using Syto-41 and Eosin-Y, respectively, and imaged using 3D two-photon laser scanning microscopy. Nuclei were segmented from images and coincident nuclei were split. The nucleus splitting procedure determines the likelihood that voxel pairs within coincident nuclei belong to the same nucleus and utilizes these likelihoods to identify individual nuclei using spectral clustering. Manual nucleus counts were used as a reference to assess the performance of our splitting procedure. Before and after splitting, automatic nucleus counts differed −26.6 ± 9.90% (p < 0.001) and −1.44 ± 7.05% (p = 0.467) from the manual reference, respectively. Whereas the slope of the relative difference between the manual and automated counts as a function of the manual count was significantly negative before splitting (p = 0.008), this slope became insignificant after splitting (p = 0.653). Smooth muscle apoptosis led to a 33.7% decrease in VSMC density (p = 0.008). Nucleus splitting improves the accuracy of automated cell content quantification in murine carotid arteries and overcomes the progressively worsening problem of coincident nuclei with increasing cell content in vessels. The presented image analysis framework provides a robust tool to quantify cell content, orientation, shape, and distribution in vessels to inform experimental and advanced computational studies on vascular structure and function.
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- 2022
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6. Schistosome infection in Senegal is associated with different spatial extents of risk and ecological drivers for Schistosoma haematobium and S. mansoni.
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Isabel J Jones, Susanne H Sokolow, Andrew J Chamberlin, Andrea J Lund, Nicolas Jouanard, Lydie Bandagny, Raphaël Ndione, Simon Senghor, Anne-Marie Schacht, Gilles Riveau, Skylar R Hopkins, Jason R Rohr, Justin V Remais, Kevin D Lafferty, Armand M Kuris, Chelsea L Wood, and Giulio De Leo
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Arctic medicine. Tropical medicine ,RC955-962 ,Public aspects of medicine ,RA1-1270 - Abstract
Schistosome parasites infect more than 200 million people annually, mostly in sub-Saharan Africa, where people may be co-infected with more than one species of the parasite. Infection risk for any single species is determined, in part, by the distribution of its obligate intermediate host snail. As the World Health Organization reprioritizes snail control to reduce the global burden of schistosomiasis, there is renewed importance in knowing when and where to target those efforts, which could vary by schistosome species. This study estimates factors associated with schistosomiasis risk in 16 villages located in the Senegal River Basin, a region hyperendemic for Schistosoma haematobium and S. mansoni. We first analyzed the spatial distributions of the two schistosomes' intermediate host snails (Bulinus spp. and Biomphalaria pfeifferi, respectively) at village water access sites. Then, we separately evaluated the relationships between human S. haematobium and S. mansoni infections and (i) the area of remotely-sensed snail habitat across spatial extents ranging from 1 to 120 m from shorelines, and (ii) water access site size and shape characteristics. We compared the influence of snail habitat across spatial extents because, while snail sampling is traditionally done near shorelines, we hypothesized that snails further from shore also contribute to infection risk. We found that, controlling for demographic variables, human risk for S. haematobium infection was positively correlated with snail habitat when snail habitat was measured over a much greater radius from shore (45 m to 120 m) than usual. S. haematobium risk was also associated with large, open water access sites. However, S. mansoni infection risk was associated with small, sheltered water access sites, and was not positively correlated with snail habitat at any spatial sampling radius. Our findings highlight the need to consider different ecological and environmental factors driving the transmission of each schistosome species in co-endemic landscapes.
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- 2021
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7. Parasitic nematodes of marine fishes from Palmyra Atoll, East Indo-Pacific, including a new species of Spinitectus (Nematoda, Cystidicolidae)
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David González-Solís, Lilia C. Soler-Jiménez, M. Leopoldina Aguirre-Macedo, John P. Mclaughlin, Jenny C. Shaw, Anna K. James, Ryan F. Hechinger, Armand M. Kuris, Kevin D. Lafferty, and Víctor M. Vidal-Martínez
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Zoology ,QL1-991 - Abstract
Here, we present the results of a taxonomic survey of the nematodes parasitizing fishes from the lagoon flats of Palmyra Atoll, Eastern Indo-Pacific. We performed quantitative parasitological surveys of 653 individual fish from each of the 44 species using the intertidal sand flats that border the atoll’s lagoon. We provide morphological descriptions, prevalence, and mean intensities of the recovered seven species of adult nematode (Pulchrascaris chiloscyllii, Capillariidae gen. sp., Cucullanus bourdini, Cucullanus oceaniensis, Pseudascarophis sp., Spinitectus (Paraspinitectus) palmyraensis sp. nov., Philometra pellucida) and three larval stages (Pulchrascaris sp., Hysterothylacium sp., Cucullanus sp.). We recorded: Pulchrascaris chiloscyllii from Carcharhinus melanopterus; Capillariidae gen. sp. from Chaetodon lunula, Lutjanus fulvus, and Ellochelon vaigiensis; Cucullanus bourdini from Arothron hispidus; Cucullanus oceaniensis from Abudefduf sordidus; Pseudascarophis sp. from Chaetodon auriga, Chaetodon lunula, and Mulloidichthys flavolineatus; Spinitectus (Paraspinitectus) palmyraensis sp. nov. from Albula glossodonta; Philometra pellucida from Arothron hispidus; and three larval forms, Pulchrascaris sp. from Acanthurus triostegus, Acanthurus xanthopterus, Rhinecanthus aculeatus, Platybelone argalus, Carangoides ferdau, Carangoides orthogrammus, Caranx ignobilis, Caranx melampygus, Caranx papuensis, Chaetodon auriga, Chanos chanos, Amblygobius phalaena, Asterropteryx semipunctata, Valencienea sexguttata, Kyphosus cinerascens, Lutjanus fulvus, Lutjanus monostigma, Ellochelon vaigiensis, Mulloidichthys flavolineatus, Upeneus taeniopterus, Gymnothorax pictus, Abudefduf septemfasciatus, Abudefduf sordidus, and Stegastes nigricans; Hysterothylacium sp. type MD from Acanthurus triostegus, Carangoides ferdau, Chaetodon lunula, Chanos chanos, Kyphosus cinerascens, Abudefduf sordidus, and Arothron hispidus; and Cucullanus sp. from Caranx ignobilis. Spinitectus (Paraspinitectus) palmyraensis sp. nov. (Cystidicolidae) is described from the intestine of roundjaw bonefish Albula glossodonta. All the nematode species reported in this study represent new geographical records. We discuss how our survey findings compare to other areas of the Indo-Pacific, and the way the relatively numerical dominance of trophically transmitted larval stages likely reflect the intact food web of Palmyra Atoll, which includes a large biomass of large-bodied top predator sharks and ray-finned fishes.
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- 2019
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8. Parasitic copepods (Crustacea, Hexanauplia) on fishes from the lagoon flats of Palmyra Atoll, Central Pacific
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Lilia C. Soler-Jiménez, F. Neptalí Morales-Serna, Ma. Leopoldina Aguirre-Macedo, John P. Mclaughlin, Alejandra G. Jaramillo, Jenny C. Shaw, Anna K. James, Ryan F. Hechinger, Armand M. Kuris, Kevin D. Lafferty, and Victor M. Vidal-Martínez
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Zoology ,QL1-991 - Abstract
We surveyed copepods parasitic on the fishes at Palmyra, a remote atoll in the Central Indo-Pacific faunal region. In total, we collected 849 individual fish, representing 44 species, from the intertidal lagoon flats at Palmyra and recovered 17 parasitic copepod species. The parasitic copepods were: Orbitacolax williamsi on Mulloidichthys flavolineatus; Anuretes serratus on Acanthurus xanthopterus; Caligus confusus on Carangoides ferdau, Carangoides orthogrammus, Caranx ignobilis, Caranx melampygus, and Caranx papuensis; Caligus kapuhili on Chaetodon auriga and Chaetodon lunula; Caligus laticaudus on Rhinecanthus aculeatus, Pseudobalistes flavimarginatus, M. flavolineatus, Upeneus taeniopterus, Chrysiptera glauca, and Epinephalus merra; Caligus mutabilis on Lutjanus fulvus and Lutjanus monostigma; Caligus randalli on C. ignobilis; Caligus sp. on L. fulvus; Caritus serratus on Chanos chanos; Lepeophtheirus lewisi on A. xanthopterus; Lepeophtheirus uluus on C. ignobilis; Dissonus similis on Arothron hispidus; Nemesis sp. on Carcharhinus melanopterus; Hatschekia longiabdominalis on A. hispidus; Hatschekia bicaudata on Chaetodon auriga and Chaetodon lunula; Kroyeria longicauda on C. melanopterus and Lernanthropus sp. on Kyphosus cinerascens. All copepod species reported here have been previously reported from the Indo-Pacific but represent new geographical records for Palmyra, demonstrating large-scale parasite dispersion strategies.
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- 2019
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9. Functional vitamin K insufficiency, vascular calcification and mortality in advanced chronic kidney disease: A cohort study.
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Lu Dai, Longkai Li, Helen Erlandsson, Armand M G Jaminon, Abdul Rashid Qureshi, Jonaz Ripsweden, Torkel B Brismar, Anna Witasp, Olof Heimbürger, Hanne Skou Jørgensen, Peter Barany, Bengt Lindholm, Pieter Evenepoel, Leon J Schurgers, and Peter Stenvinkel
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Medicine ,Science - Abstract
Patients with chronic kidney disease (CKD) suffer from vitamin K deficiency and are at high risk of vascular calcification (VC) and premature death. We investigated the association of functional vitamin K deficiency with all-cause mortality and whether this association is modified by the presence of VC in CKD stage 5 (CKD G5). Plasma dephosphorylated-uncarboxylated matrix Gla-protein (dp-ucMGP), a circulating marker of functional vitamin K deficiency, and other laboratory and clinical data were determined in 493 CKD G5 patients. VC was assessed in subgroups by Agatston scoring of coronary artery calcium (CAC) and aortic valve calcium (AVC). Backward stepwise regression did not identify dp-ucMGP as an independent determinant of VC. During a median follow-up of 42 months, 93 patients died. Each one standard deviation increment in dp-ucMGP was associated with increased risk of all-cause mortality (sub-hazard ratio (sHR) 1.17; 95% confidence interval, 1.01-1.37) adjusted for age, sex, cardiovascular disease, diabetes, body mass index, inflammation, and dialysis treatment. The association remained significant when further adjusted for CAC and AVC in sub-analyses (sHR 1.22, 1.01-1.48 and 1.27, 1.01-1.60, respectively). In conclusion, functional vitamin K deficiency associates with increased mortality risk that is independent of the presence of VC in patients with CKD G5.
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- 2021
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10. A 4-Week Diet Low or High in Advanced Glycation Endproducts Has Limited Impact on Gut Microbial Composition in Abdominally Obese Individuals: The deAGEing Trial
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Armand M. A. Linkens, Niels van Best, Petra M. Niessen, Nicole E. G. Wijckmans, Erica E. C. de Goei, Jean L. J. M. Scheijen, Martien C. J. M. van Dongen, Christel C. J. A. W. van Gool, Willem M. de Vos, Alfons J. H. M. Houben, Coen D. A. Stehouwer, Simone J. M. P. Eussen, John Penders, and Casper G. Schalkwijk
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dietary advanced glycation end products ,dietary dicarbonyls ,UPLC-MS/MS ,RCT ,gut microbiota ,16S rRNA ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Dietary advanced glycation endproducts (AGEs), abundantly present in Westernized diets, are linked to negative health outcomes, but their impact on the gut microbiota has not yet been well investigated in humans. We investigated the effects of a 4-week isocaloric and macronutrient-matched diet low or high in AGEs on the gut microbial composition of 70 abdominally obese individuals in a double-blind parallel-design randomized controlled trial (NCT03866343). Additionally, we investigated the cross-sectional associations between the habitual intake of dietary dicarbonyls, reactive precursors to AGEs, and the gut microbial composition, as assessed by 16S rRNA amplicon-based sequencing. Despite a marked percentage difference in AGE intake, we observed no differences in microbial richness and the general community structure. Only the Anaerostipes spp. had a relative abundance >0.5% and showed differential abundance (0.5 versus 1.11%; p = 0.028, after low- or high-AGE diet, respectively). While the habitual intake of dicarbonyls was not associated with microbial richness or a general community structure, the intake of 3-deoxyglucosone was especially associated with an abundance of several genera. Thus, a 4-week diet low or high in AGEs has a limited impact on the gut microbial composition of abdominally obese humans, paralleling its previously observed limited biological consequences. The effects of dietary dicarbonyls on the gut microbiota composition deserve further investigation.
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- 2022
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11. Women’s health in The BMJ: a data science history
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Eva N Hamulyák, Austin J Brockmeier, Johanna D Killas, Sophia Ananiadou, and Armand M Leroi
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Medicine - Abstract
Objective To determine how the representation of women’s health has changed in clinical studies over the course of 70 years.Design Observational study of 71 866 research articles published between 1948 and 2018 in The BMJ.Main outcome measures The incidence of women-specific health topics over time. General linear, additive and segmented regression models were used to estimate trends.Results Over 70 years, the overall odds that a word in a BMJ research article was ‘woman’ or ‘women’ increased by an annual factor of 1.023, but this rate of increase varied by clinical specialty with some showing little or no change. The odds that an article was about some aspect of women-specific health increased much more slowly, by an annual factor of 1.004. The incidence of articles about particular areas of women-specific medicine such as pregnancy did not show a general increase, but rather fluctuated over time. The incidence of articles making any mention of women, gender or sex declined between 1948 and 2005, after which it rose steeply so that by 2018 few papers made no mention of them at all.Conclusions Over time women have become ever more prominent in BMJ research articles. However, the importance of women-specific health topics has waxed and waned as researchers responded ephemerally to medical advances, public health programmes, and sociolegal changes. The appointment of a woman editor-inchief in 2005 may have had a dramatic effect on whether women were mentioned in research articles.
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- 2020
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12. Development of the BioHybrid Assay: Combining Primary Human Vascular Smooth Muscle Cells and Blood to Measure Vascular Calcification Propensity
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Armand M. G. Jaminon, Asim C. Akbulut, Niko Rapp, Rafael Kramann, Erik A. L. Biessen, Lieve Temmerman, Barend Mees, Vincent Brandenburg, Robert Dzhanaev, Willi Jahnen-Dechent, Juergen Floege, Jouni Uitto, Chris P. Reutelingsperger, and Leon J. Schurgers
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vascular calcification ,vascular smooth muscle cells ,BioHybrid ,fetuin-A ,matrix Gla protein ,vitamin K ,Cytology ,QH573-671 - Abstract
Background: Vascular calcification is an active process that increases cardiovascular disease (CVD) risk. There is still no consensus on an appropriate biomarker for vascular calcification. We reasoned that the biomarker for vascular calcification is the collection of all blood components that can be sensed and integrated into a calcification response by human vascular smooth muscle cells (hVSMCs). Methods: We developed a new cell-based high-content assay, the BioHybrid assay, to measure in vitro calcification. The BioHybrid assay was compared with the o-Cresolphthalein assay and the T50 assay. Serum and plasma were derived from different cohort studies including chronic kidney disease (CKD) stages III, IV, V and VD (on dialysis), pseudoxanthoma elasticum (PXE) and other cardiovascular diseases including serum from participants with mild and extensive coronary artery calcification (CAC). hVSMCs were exposed to serum and plasma samples, and in vitro calcification was measured using AlexaFluor®-546 tagged fetuin-A as calcification sensor. Results: The BioHybrid assay measured the kinetics of calcification in contrast to the endpoint o-Cresolphthalein assay. The BioHybrid assay was more sensitive to pick up differences in calcification propensity than the T50 assay as determined by measuring control as well as pre- and post-dialysis serum samples of CKD patients. The BioHybrid response increased with CKD severity. Further, the BioHybrid assay discriminated between calcification propensity of individuals with a high CAC index and individuals with a low CAC index. Patients with PXE had an increased calcification response in the BioHybrid assay as compared to both spouse and control plasma samples. Finally, vitamin K1 supplementation showed lower in vitro calcification, reflecting changes in delta Agatston scores. Lower progression within the BioHybrid and on Agatston scores was accompanied by lower dephosphorylated-uncarboxylated matrix Gla protein levels. Conclusion: The BioHybrid assay is a novel approach to determine the vascular calcification propensity of an individual and thus may add to personalised risk assessment for CVD.
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- 2021
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13. 13C Labeling of Nematode Worms to Improve Metabolome Coverage by Heteronuclear Nuclear Magnetic Resonance Experiments
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Florian M. Geier, Armand M. Leroi, and Jacob G. Bundy
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C. elegans ,HSQC ,CT-HSQC ,sensitivity ,metabolomics ,metabolome ,Biology (General) ,QH301-705.5 - Abstract
Nuclear magnetic resonance (NMR) spectroscopy is widely used as a metabolomics tool, and 1D spectroscopy is overwhelmingly the commonest approach. The use of 2D spectroscopy could offer significant advantages in terms of increased spectral dispersion of peaks, but has a number of disadvantages—in particular, heteronuclear 2D spectroscopy is often much less sensitive than 1D NMR. One factor contributing to this low sensitivity in 13C/1H heteronuclear NMR is the low natural abundance of the 13C stable isotope; as a consequence, where it is possible to label biological material with 13C, there is a potential enhancement of sensitivity of up to around 90fold. However, there are some problems that can reduce the advantages otherwise gained—in particular, the fine structure arising from 13C/13C coupling, which is essentially non-existent at natural abundance, can reduce the possible sensitivity gain and increase the chances of peak overlap. Here, we examined the use of two different heteronuclear single quantum coherence (HSQC) pulse sequences for the analysis of fully 13C-labeled tissue extracts from Caenorhabditis elegans nematodes. The constant time ct-HSQC had improved peak shape, and consequent better peak detection of metabolites from a labeled extract; matching this against reference spectra from the HMDB gave a match to about 300 records (although fewer actual metabolites, as some of these represent false positive matches). This approach gives a rapid and automated initial metabolome assignment, forming an ideal basis for further manual curation.
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- 2019
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14. Viviparity stimulates diversification in an order of fish
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Andrew J. Helmstetter, Alexander S. T. Papadopulos, Javier Igea, Tom J. M. Van Dooren, Armand M. Leroi, and Vincent Savolainen
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Science - Abstract
Live birth and an annual life cycle potentially enable access to new ecological niches and subsequent species diversification. Here, Helmstetter et al.build the phylogeny for fish in the order Cyprinodontiformes and find that, though live birth and annualism have each evolved multiple times, only live birth is associated with increased diversification.
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- 2016
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15. Seroprevalence of Baylisascaris procyonis Infection among Humans, Santa Barbara County, California, USA, 2014–2016
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Sara B. Weinstein, Camille M. Lake, Holly M. Chastain, David Fisk, Sukwan Handali, Philip L. Kahn, Susan P. Montgomery, Patricia P. Wilkins, Armand M. Kuris, and Kevin D. Lafferty
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nematode infections ,enteric infections ,parasites ,Ascaridoidea ,roundworm nematode ,raccoon roundworm ,Medicine ,Infectious and parasitic diseases ,RC109-216 - Abstract
Baylisascaris procyonis (raccoon roundworm) infection is common in raccoons and can cause devastating pathology in other animals, including humans. Limited information is available on the frequency of asymptomatic human infection. We tested 150 adults from California, USA, for B. procyonis antibodies; 11 were seropositive, suggesting that subclinical infection does occur.
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- 2017
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16. Global Assessment of Schistosomiasis Control Over the Past Century Shows Targeting the Snail Intermediate Host Works Best.
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Susanne H Sokolow, Chelsea L Wood, Isabel J Jones, Scott J Swartz, Melina Lopez, Michael H Hsieh, Kevin D Lafferty, Armand M Kuris, Chloe Rickards, and Giulio A De Leo
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Arctic medicine. Tropical medicine ,RC955-962 ,Public aspects of medicine ,RA1-1270 - Abstract
BACKGROUND:Despite control efforts, human schistosomiasis remains prevalent throughout Africa, Asia, and South America. The global schistosomiasis burden has changed little since the new anthelmintic drug, praziquantel, promised widespread control. METHODOLOGY:We evaluated large-scale schistosomiasis control attempts over the past century and across the globe by identifying factors that predict control program success: snail control (e.g., molluscicides or biological control), mass drug administrations (MDA) with praziquantel, or a combined strategy using both. For data, we compiled historical information on control tactics and their quantitative outcomes for all 83 countries and territories in which: (i) schistosomiasis was allegedly endemic during the 20th century, and (ii) schistosomiasis remains endemic, or (iii) schistosomiasis has been "eliminated," or is "no longer endemic," or transmission has been interrupted. PRINCIPAL FINDINGS:Widespread snail control reduced prevalence by 92 ± 5% (N = 19) vs. 37 ± 7% (N = 29) for programs using little or no snail control. In addition, ecological, economic, and political factors contributed to schistosomiasis elimination. For instance, snail control was most common and widespread in wealthier countries and when control began earlier in the 20th century. CONCLUSIONS/SIGNIFICANCE:Snail control has been the most effective way to reduce schistosomiasis prevalence. Despite evidence that snail control leads to long-term disease reduction and elimination, most current schistosomiasis control efforts emphasize MDA using praziquantel over snail control. Combining drug-based control programs with affordable snail control seems the best strategy for eliminating schistosomiasis.
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- 2016
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17. Parasites alter food-web topology of a subarctic lake food web and its pelagic and benthic compartments
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Moore, Shannon E., Siwertsson, Anna, Lafferty, Kevin D., Kuris, Armand M., Soldánová, Miroslava, Morton, Dana, Primicerio, Raul, and Amundsen, Per-Arne
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- 2024
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18. The evolution of popular music: USA 1960–2010
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Matthias Mauch, Robert M. MacCallum, Mark Levy, and Armand M. Leroi
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popular music ,diversity ,stylistic revolutions ,cultural evolution ,Science - Abstract
In modern societies, cultural change seems ceaseless. The flux of fashion is especially obvious for popular music. While much has been written about the origin and evolution of pop, most claims about its history are anecdotal rather than scientific in nature. To rectify this, we investigate the US Billboard Hot 100 between 1960 and 2010. Using music information retrieval and text-mining tools, we analyse the musical properties of approximately 17 000 recordings that appeared in the charts and demonstrate quantitative trends in their harmonic and timbral properties. We then use these properties to produce an audio-based classification of musical styles and study the evolution of musical diversity and disparity, testing, and rejecting, several classical theories of cultural change. Finally, we investigate whether pop musical evolution has been gradual or punctuated. We show that, although pop music has evolved continuously, it did so with particular rapidity during three stylistic ‘revolutions’ around 1964, 1983 and 1991. We conclude by discussing how our study points the way to a quantitative science of cultural change.
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- 2015
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19. Parasites affect food web structure primarily through increased diversity and complexity.
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Jennifer A Dunne, Kevin D Lafferty, Andrew P Dobson, Ryan F Hechinger, Armand M Kuris, Neo D Martinez, John P McLaughlin, Kim N Mouritsen, Robert Poulin, Karsten Reise, Daniel B Stouffer, David W Thieltges, Richard J Williams, and Claus Dieter Zander
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Biology (General) ,QH301-705.5 - Abstract
Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites "dominate" food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites' roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites' feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic organization, identifies limitations of current food web models, and provides direction for future structural and dynamical models.
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- 2013
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20. Influence of the PEO molecular weight on the processability and performance of SSB cathode composite electrodes
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Martin-Ortiz, J., Blanco, J., Armand, M., Otaegui, L., Morant-Miñana, M.C., and Villaverde, A.
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- 2024
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21. Intertidal Parasites and Commensals
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KURIS, ARMAND M., primary
- Published
- 2023
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- View/download PDF
22. Nematomorpha
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KURIS, ARMAND M., primary
- Published
- 2023
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- View/download PDF
23. Acanthocephala
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KURIS, ARMAND M., primary
- Published
- 2023
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24. Classifying Organisms and Artefacts By Their Shapes
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Salili-James, Arianna, Mackay, Anne, Rodriguez-Alvarez, Emilio, Rodriguez-Perez, Diana, Mannack, Thomas, Rawlings, Timothy A., Palmer, A. Richard, Todd, Jonathan, Riutta, Terhi E., Macinnis-Ng, Cate, Han, Zhitong, Davies, Megan, Thorpe, Zinnia, Marsland, Stephen, and Leroi, Armand M.
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Computer Science - Computer Vision and Pattern Recognition ,Statistics - Methodology ,62P99 - Abstract
We often wish to classify objects by their shapes. Indeed, the study of shapes is an important part of many scientific fields such as evolutionary biology, structural biology, image processing, and archaeology. The most widely-used method of shape analysis, Geometric Morphometrics, assumes that that the mathematical space in which shapes are represented is linear. However, it has long been known that shape space is, in fact, rather more complicated, and certainly non-linear. Diffeomorphic methods that take this non-linearity into account, and so give more accurate estimates of the distances among shapes, exist but have rarely been applied to real-world problems. Using a machine classifier, we tested the ability of several of these methods to describe and classify the shapes of a variety of organic and man-made objects. We find that one method, the Square-Root Velocity Function (SRVF), is superior to all others, including a standard Geometric Morphometric method (eigenshapes). We also show that computational shape classifiers outperform human experts, and that the SRVF shortest-path between shapes can be used to estimate the shapes of intermediate steps in evolutionary series. Diffeomorphic shape analysis methods, we conclude, now provide practical and effective solutions to many shape description and classification problems in the natural and human sciences., Comment: 7 pages, 6 figures
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- 2021
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25. Schistosome infection in Senegal is associated with different spatial extents of risk and ecological drivers for Schistosoma haematobium and S. mansoni.
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Jones, Isabel J, Sokolow, Susanne H, Chamberlin, Andrew J, Lund, Andrea J, Jouanard, Nicolas, Bandagny, Lydie, Ndione, Raphaël, Senghor, Simon, Schacht, Anne-Marie, Riveau, Gilles, Hopkins, Skylar R, Rohr, Jason R, Remais, Justin V, Lafferty, Kevin D, Kuris, Armand M, Wood, Chelsea L, and De Leo, Giulio
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Infectious Diseases ,Rare Diseases ,Biotechnology ,Digestive Diseases ,Vector-Borne Diseases ,2.2 Factors relating to the physical environment ,Infection ,Tropical Medicine ,Biological Sciences ,Medical and Health Sciences - Abstract
Schistosome parasites infect more than 200 million people annually, mostly in sub-Saharan Africa, where people may be co-infected with more than one species of the parasite. Infection risk for any single species is determined, in part, by the distribution of its obligate intermediate host snail. As the World Health Organization reprioritizes snail control to reduce the global burden of schistosomiasis, there is renewed importance in knowing when and where to target those efforts, which could vary by schistosome species. This study estimates factors associated with schistosomiasis risk in 16 villages located in the Senegal River Basin, a region hyperendemic for Schistosoma haematobium and S. mansoni. We first analyzed the spatial distributions of the two schistosomes' intermediate host snails (Bulinus spp. and Biomphalaria pfeifferi, respectively) at village water access sites. Then, we separately evaluated the relationships between human S. haematobium and S. mansoni infections and (i) the area of remotely-sensed snail habitat across spatial extents ranging from 1 to 120 m from shorelines, and (ii) water access site size and shape characteristics. We compared the influence of snail habitat across spatial extents because, while snail sampling is traditionally done near shorelines, we hypothesized that snails further from shore also contribute to infection risk. We found that, controlling for demographic variables, human risk for S. haematobium infection was positively correlated with snail habitat when snail habitat was measured over a much greater radius from shore (45 m to 120 m) than usual. S. haematobium risk was also associated with large, open water access sites. However, S. mansoni infection risk was associated with small, sheltered water access sites, and was not positively correlated with snail habitat at any spatial sampling radius. Our findings highlight the need to consider different ecological and environmental factors driving the transmission of each schistosome species in co-endemic landscapes.
- Published
- 2021
26. Asymptotic degree distributions in random threshold graphs
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Makowski, Armand M. and Pal, Siddharth
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Mathematics - Probability ,Condensed Matter - Statistical Mechanics ,Computer Science - Discrete Mathematics ,Computer Science - Social and Information Networks - Abstract
We discuss several limiting degree distributions for a class of random threshold graphs in the many node regime. This analysis is carried out under a weak assumption on the distribution of the underlying fitness variable. This assumption, which is satisfied by the exponential distribution, determines a natural scaling under which the following limiting results are shown: The nodal degree distribution, i.e., the distribution of any node, converges in distribution to a limiting pmf. However, for each $d=0,1, \ldots $, the fraction of nodes with given degree $d$ converges only in distribution to a non-degenerate random variable $\Pi(d)$ (whose distribution depends on $d$),and not in probability to the aforementioned limiting nodal pmf as is customarily expected. The distribution of $\Pi(d)$ is identified only through its characteristic function. Implications of this result include: (i) The empirical node distribution may not be used as a proxy for or as an estimate to the limiting nodal pmf; (ii) Even in homogeneous graphs, the network-wide degree distribution and the nodal degree distribution may capture vastly different information; and (iii) Random threshold graphs with exponential distributed fitness do not provide an alternative scale-free model to the Barab\'asi-Albert model as was argued by some authors; the two models cannot be meaningfully compared in terms of their degree distributions!
- Published
- 2019
27. Node isolation in large homogeneous binary multiplicative attribute graph models
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Qu, Sikai and Makowski, Armand M.
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Computer Science - Social and Information Networks ,Mathematics - Probability - Abstract
The multiplicative attribute graph (MAG) model was introduced by Kim and Leskovec as a mathematically tractable model of certain classes of real-world networks. It is an instance of hidden graph models, and implements the plausible idea that network structure is collectively shaped by attributes individually associated with nodes. These authors have studied several aspects of this model, including its connectivity, the existence of a giant component,its diameter and the degree distribution. This was done in the asymptotic regime when the number of nodes and the number of node attributes both grow unboundedly large, the latter scaling with the former under a natural admissibility condition. In the same setting, we explore the existence (or equivalently, absence) of isolated nodes, a property not discussed in the original paper. The main result of the paper is a {\em zero-one} law for the absence of isolated nodes; this zero-one law coincides with that obtained by Kim and Leskovec for graph connectivity (although under slightly weaker assumptions). We prove these results by applying the method of first and second moments in a non-standard way to multiple sets of counting random variables associated with the number of isolated nodes., Comment: arXiv admin note: text overlap with arXiv:1810.10114
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- 2019
28. Hermaphrodites and parasitism: size-specific female reproduction drives infection by an ephemeral parasitic castrator.
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Fong, Caitlin R, Kuris, Armand M, and Hechinger, Ryan F
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Animals ,Isopoda ,Thoracica ,Probability ,Ecology ,Ecosystem ,Population Dynamics ,Symbiosis ,Reproduction ,Geography ,California ,Female ,Male ,Host-Parasite Interactions ,Hermaphroditic Organisms - Abstract
Sex can influence patterns of parasitism because males and females can differ in encounter with, and susceptibility to, parasites. We investigate an isopod parasite (Hemioniscus balani) that consumes ovarian fluid, blocking female function of its barnacle host, a simultaneous hermaphrodite. As a hermaphrodite, sex is fluid, and individuals may allocate energy differentially to male versus female reproduction. We predicted the relationship between barnacle size and female reproductive function influences the distribution of parasites within barnacle populations. We surveyed 12 populations spanning ~400 km of coastline of southern California and found intermediate-sized barnacles where most likely to be actively functioning as females. While it is unclear why larger individuals are less likely to be actively reproducing as females, we suggest this reduced likelihood is driven by increased investment in male reproductive effort at larger sizes. The female function-size relationship was mirrored by the relationship between size and parasitism. We suggest parasitism by Hemioniscus balani imposes a cost to female function, reinforcing the lack of investment in female function by the largest individuals. Within the subset of suitable (=female) hosts, infection probability increased with size. Hence, the distribution of female function, combined with selection for larger hosts, primarily dictated patterns of infection.
- Published
- 2019
29. Delaying the onset of coulombic efficiency loss by adjusting the composite cathode processing parameters
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Morant-Miñana, M.C., Fernandez-Diaz, L., Liendo, G., Blanco, J., Martin-Fuentes, S., Armand, M., Otaegui, L., and Villaverde, A.
- Published
- 2023
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- View/download PDF
30. Deficiency in homologous recombination is associated with changes in cell cycling and morphology in Saccharomyces cerevisiae
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Holland, Cory L., Weis, Monica F., England, Corbin J., Berry, Armand M., Hall, Paige D., and Lewis, L. Kevin
- Published
- 2023
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- View/download PDF
31. On the log-normality of the degree distribution in large homogeneous binary multiplicative attribute graph models
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Qu, Sikai and Makowski, Armand M.
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Computer Science - Social and Information Networks - Abstract
The muliplicative attribute graph (MAG) model was introduced by Kim and Leskovec as a mathematically tractable model for networks where network structure is believed to be shaped by features or attributes associated with individual nodes. For large homogeneous binary MAGs, they argued through approximation arguments that the "tail of [the] degree distribution follows a log-normal distribution" as the number of nodes becomes unboundedly large and the number of attributes scales logarithmically with the number of nodes. Under the same limiting regime, we revisit the asymptotic behavior of the degree distribution: Under weaker conditions we obtain a precise convergence result to log-normality, develop from it reasoned log-normal approximations to the degree distribution and derive various rates of convergence. In particular, we show that a certain transformation of the node degree converges in distribution to a log-normal distribution, and give its convergence rate in the form of a Berry-Esseen type estimate.
- Published
- 2018
32. Insomnia Disorder Among Older Veterans: Results of a Postal Survey.
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Ryden, Armand M, Martin, Jennifer L, Matsuwaka, Sean, Fung, Constance H, Dzierzewski, Joseph M, Song, Yeonsu, Mitchell, Michael N, Fiorentino, Lavinia, Josephson, Karen R, Jouldjian, Stella, and Alessi, Cathy A
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Biomedical and Clinical Sciences ,Clinical Sciences ,Brain Disorders ,Aging ,Behavioral and Social Science ,Sleep Research ,Age Factors ,Aged ,Aged ,80 and over ,Cross-Sectional Studies ,Female ,Humans ,Male ,Middle Aged ,Prevalence ,Self Report ,Sleep Initiation and Maintenance Disorders ,Surveys and Questionnaires ,United States ,Veterans ,aging ,insomnia ,self-rated health ,survey study ,Other Medical and Health Sciences ,Psychology ,Neurology & Neurosurgery ,Clinical sciences - Abstract
Study objectivesTo estimate the prevalence of insomnia disorder among older veterans and to study relationships among age and self-rated health, with insomnia disorder, self-reported sleep duration and sleep efficiency.MethodsA cross-sectional postal survey of community-dwelling older veterans (older than 60 years) seen at one VA Healthcare System in the prior 18 months was performed, which was constructed to align with the general diagnostic criteria for insomnia disorder (International Classification of Sleep Disorders, Second Edition [ICSD-2]). The survey also queried self-reported sleep duration, bedtime, and wake time, which were used to calculate sleep efficiency. The survey also asked about race/ethnicity and self-rated health (using the general health item from the Short Form-36).ResultsA completed survey was returned by 4,717 individuals (51.9% response rate; mean age 74.1 years). Of those, 2,249 (47.7%) met ICSD-2 diagnostic criteria for insomnia disorder. In logistic regression analyses, insomnia disorder was more likely among younger age categories (odds ratios [OR] 1.4-2.5) and in those with worse self-rated health (OR 2.1-14.4). Both total nocturnal sleep time and time in bed increased with older age (all P < .001), whereas sleep efficiency did not differ. Worse self-rated health was associated with shorter total nocturnal sleep time, more time in bed, and lower (worse) sleep efficiency.ConclusionsResults of the postal survey suggest that almost half of community-dwelling older veterans have insomnia disorder, which was more common in young-old and among those with worse self-rated health. Additional work is needed to address the high burden of insomnia among older adults, including those with poor health.
- Published
- 2019
33. Parasitic copepods (Crustacea, Hexanauplia) on fishes from the lagoon flats of Palmyra Atoll, Central Pacific
- Author
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Soler-Jiménez, Lilia C, Morales-Serna, F Neptalí, Aguirre-Macedo, Ma Leopoldina, McLaughlin, John P, Jaramillo, Alejandra G, Shaw, Jenny C, James, Anna K, Hechinger, Ryan F, Kuris, Armand M, Lafferty, Kevin D, and Vidal-Martínez, Victor M
- Subjects
Biological Sciences ,Ecology ,Parasitic copepods ,fish ,geographical isolation ,islands ,Indo-Pacific ,atoll ,Evolutionary Biology ,Zoology ,Evolutionary biology - Abstract
We surveyed copepods parasitic on the fishes at Palmyra, a remote atoll in the Central Indo-Pacific faunal region. In total, we collected 849 individual fish, representing 44 species, from the intertidal lagoon flats at Palmyra and recovered 17 parasitic copepod species. The parasitic copepods were: Orbitacolaxwilliamsi on Mulloidichthysflavolineatus; Anuretesserratus on Acanthurusxanthopterus; Caligusconfusus on Carangoidesferdau, Carangoidesorthogrammus, Caranxignobilis, Caranxmelampygus, and Caranxpapuensis; Caliguskapuhili on Chaetodonauriga and Chaetodonlunula; Caliguslaticaudus on Rhinecanthusaculeatus, Pseudobalistesflavimarginatus, M.flavolineatus, Upeneustaeniopterus, Chrysipteraglauca, and Epinephalusmerra; Caligusmutabilis on Lutjanusfulvus and Lutjanusmonostigma; Caligusrandalli on C.ignobilis; Caligus sp. on L.fulvus; Caritusserratus on Chanoschanos; Lepeophtheiruslewisi on A.xanthopterus; Lepeophtheirusuluus on C.ignobilis; Dissonussimilis on Arothronhispidus; Nemesis sp. on Carcharhinusmelanopterus; Hatschekialongiabdominalis on A.hispidus; Hatschekiabicaudata on Chaetodonauriga and Chaetodonlunula; Kroyerialongicauda on C.melanopterus and Lernanthropus sp. on Kyphosuscinerascens. All copepod species reported here have been previously reported from the Indo-Pacific but represent new geographical records for Palmyra, demonstrating large-scale parasite dispersion strategies.
- Published
- 2019
34. Parasitic nematodes of marine fishes from Palmyra Atoll, East Indo-Pacific, including a new species of Spinitectus (Nematoda, Cystidicolidae)
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González-Solís, David, Soler-Jiménez, Lilia C, Aguirre-Macedo, M Leopoldina, McLaughlin, John P, Shaw, Jenny C, James, Anna K, Hechinger, Ryan F, Kuris, Armand M, Lafferty, Kevin D, and Vidal-Martínez, Víctor M
- Subjects
Biological Sciences ,Ecology ,Evolutionary Biology ,Life Below Water ,Cucullanus ,Hysterothylacium ,Paraspinitectus ,Philometra ,Pseudascarophis ,Pulchrascaris ,Cucullanus ,Hysterothylacium ,Paraspinitectus ,Philometra ,Pseudascarophis ,Pulchrascaris ,Zoology ,Evolutionary biology - Abstract
Here, we present the results of a taxonomic survey of the nematodes parasitizing fishes from the lagoon flats of Palmyra Atoll, Eastern Indo-Pacific. We performed quantitative parasitological surveys of 653 individual fish from each of the 44 species using the intertidal sand flats that border the atoll's lagoon. We provide morphological descriptions, prevalence, and mean intensities of the recovered seven species of adult nematode (Pulchrascaris chiloscyllii, Capillariidae gen. sp., Cucullanus bourdini, Cucullanus oceaniensis, Pseudascarophis sp., Spinitectus (Paraspinitectus) palmyraensissp. nov., Philometra pellucida) and three larval stages (Pulchrascaris sp., Hysterothylacium sp., Cucullanus sp.). We recorded: Pulchrascaris chiloscyllii from Carcharhinus melanopterus; Capillariidae gen. sp. from Chaetodon lunula, Lutjanus fulvus, and Ellochelon vaigiensis; Cucullanus bourdini from Arothron hispidus; Cucullanus oceaniensis from Abudefduf sordidus; Pseudascarophis sp. from Chaetodon auriga, Chaetodon lunula, and Mulloidichthys flavolineatus; Spinitectus (Paraspinitectus) palmyraensissp. nov. from Albula glossodonta; Philometra pellucida from Arothron hispidus; and three larval forms, Pulchrascaris sp. from Acanthurus triostegus, Acanthurus xanthopterus, Rhinecanthus aculeatus, Platybelone argalus, Carangoides ferdau, Carangoides orthogrammus, Caranx ignobilis, Caranx melampygus, Caranx papuensis, Chaetodon auriga, Chanos chanos, Amblygobius phalaena, Asterropteryx semipunctata, Valencienea sexguttata, Kyphosus cinerascens, Lutjanus fulvus, Lutjanus monostigma, Ellochelon vaigiensis, Mulloidichthys flavolineatus, Upeneus taeniopterus, Gymnothorax pictus, Abudefduf septemfasciatus, Abudefduf sordidus, and Stegastes nigricans; Hysterothylacium sp. type MD from Acanthurus triostegus, Carangoides ferdau, Chaetodon lunula, Chanos chanos, Kyphosus cinerascens, Abudefduf sordidus, and Arothron hispidus; and Cucullanus sp. from Caranx ignobilis. Spinitectus (Paraspinitectus) palmyraensissp. nov. (Cystidicolidae) is described from the intestine of roundjaw bonefish Albula glossodonta. All the nematode species reported in this study represent new geographical records. We discuss how our survey findings compare to other areas of the Indo-Pacific, and the way the relatively numerical dominance of trophically transmitted larval stages likely reflect the intact food web of Palmyra Atoll, which includes a large biomass of large-bodied top predator sharks and ray-finned fishes.
- Published
- 2019
35. Evidence gaps and diversity among potential win–win solutions for conservation and human infectious disease control
- Author
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Hopkins, Skylar R, Lafferty, Kevin D, Wood, Chelsea L, Olson, Sarah H, Buck, Julia C, De Leo, Giulio A, Fiorella, Kathryn J, Fornberg, Johanna L, Garchitorena, Andres, Jones, Isabel J, Kuris, Armand M, Kwong, Laura H, LeBoa, Christopher, Leon, Ariel E, Lund, Andrea J, MacDonald, Andrew J, Metz, Daniel C G, Nova, Nicole, Peel, Alison J, Remais, Justin V, Stewart Merrill, Tara E, Wilson, Maya, Bonds, Matthew H, Dobson, Andrew P, Lopez Carr, David, Howard, Meghan E, Mandle, Lisa, and Sokolow, Susanne H
- Published
- 2022
- Full Text
- View/download PDF
36. Asymptotic degree distributions in large (homogeneous) random networks: A little theory and a counterexample
- Author
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Pal, Siddharth and Makowski, Armand M.
- Subjects
Computer Science - Social and Information Networks ,Computer Science - Discrete Mathematics ,Mathematics - Probability ,Physics - Physics and Society - Abstract
In random graph models, the degree distribution of an individual node should be distinguished from the (empirical) degree distribution of the graph that records the fractions of nodes with given degree. We introduce a general framework to explore when these two degree distributions coincide asymptotically in large homogeneous random networks. The discussion is carried under three basic statistical assumptions on the degree sequences: (i) a weak form of distributional homogeneity; (ii) the existence of an asymptotic (nodal) degree distribution; and (iii) a weak form of asymptotic uncorrelatedness. We show that this asymptotic equality may fail in homogeneous random networks for which (i) and (ii) hold but (iii) does not. The counterexample is found in the class of random threshold graphs. An implication of this finding is that random threshold graphs cannot be used as a substitute to the Barab\'asi-Albert model for scale-free network modeling, as has been proposed by some authors. The results can also be formulated for non-homogeneous models by making use of a random sampling procedure over the nodes.
- Published
- 2017
37. Light traffic behavior under the power-of-two load balancing strategy: The case of heterogeneous servers
- Author
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Izagirre, Ane and Makowski, Armand M.
- Subjects
Computer Science - Performance - Abstract
We consider a multi-server queueing system under the power-of-two policy with Poisson job arrivals, heterogeneous servers and a general job requirement distribution; each server operates under the first-come first-serve policy and there are no buffer constraints. We analyze the performance of this system in light traffic by evaluating the first two light traffic derivatives of the average job response time. These expressions point to several interesting structural features associated with server heterogeneity in light traffic: For unequal capacities, the average job response time is seen to decrease for small values of the arrival rate, and the more diverse the server speeds, the greater the gain in performance. These theoretical findings are assessed through limited simulations., Comment: 30 pages, 13 figures
- Published
- 2017
38. Counting triangles, tunable clustering and the small-world property in random key graphs (Extended version)
- Author
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Yağan, Osman and Makowski, Armand M.
- Subjects
Computer Science - Social and Information Networks ,Computer Science - Discrete Mathematics ,Mathematics - Probability - Abstract
Random key graphs were introduced to study various properties of the Eschenauer-Gligor key predistribution scheme for wireless sensor networks (WSNs). Recently this class of random graphs has received much attention in contexts as diverse as recommender systems, social network modeling, and clustering and classification analysis. This paper is devoted to analyzing various properties of random key graphs. In particular, we establish a zero-one law for the the existence of triangles in random key graphs, and identify the corresponding critical scaling. This zero-one law exhibits significant differences with the corresponding result in Erdos-Renyi (ER) graphs. We also compute the clustering coefficient of random key graphs, and compare it to that of ER graphs in the many node regime when their expected average degrees are asymptotically equivalent. For the parameter range of practical relevance in both wireless sensor network and social network applications, random key graphs are shown to be much more clustered than the corresponding ER graphs. We also explore the suitability of random key graphs as small world models in the sense of Watts and Strogatz., Comment: 16 pages. Submitted. arXiv admin note: text overlap with arXiv:0910.0499
- Published
- 2017
39. Parental care reduces parasite-induced mortality in a coral reef fish.
- Author
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Grutter, Alexandra S., Blomberg, Simone P., Duong, Berilin, Fargher, Bronwyn E., Feeney, William E., McCormick, Mark I., Nicholson, Matthew D., Sikkel, Paul C., Warner, Robert R., and Kuris, Armand M.
- Subjects
CORAL reef fishes ,CORAL communities ,LAND settlement patterns ,FISHING villages ,ISOPODA - Abstract
Settlement patterns of juvenile fish shape coral reef communities. During the recruitment process, predation rates are extremely high. However, the role that parental care plays in reducing mortality, especially by cryptic natural enemies such as parasites, remains largely unstudied. We investigated whether parental care in the spiny chromis damselfish (Acanthochromis polyacanthus) protects juveniles from parasite-induced mortality by gnathiid isopods (Gnathia aureamaculosa). Using laboratory experiments, we found that survival of recently hatched juveniles when exposed to gnathiids was higher when parents were present (77%) than when parents were absent (25%). Investigation of their faeces in the field and laboratory indicates that adults consume gnathiids. Together, our data suggest that parental care plays a key role in reducing parasite-induced mortality of juvenile spiny chromis via parental consumption of gnathiids. This highlights the overlooked role of parasites as a source of high mortality in juvenile coral reef fishes and the composition of coral reef fish communities. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Robert Kent Trench (1940–2021): a life devoted to symbiotic mutualisms and seeking nature’s truth
- Author
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LaJeunesse, Todd C., Banaszak, Anastazia T., Fisher, Charles R., Shick, J. Malcolm, Warner, Mark E., Porter, James W., Kuris, Armand M., Iglesias-Prieto, Roberto, and Fitt, William K.
- Published
- 2021
- Full Text
- View/download PDF
41. Nearly 400 million people are at higher risk of schistosomiasis because dams block the migration of snail-eating river prawns
- Author
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Sokolow, Susanne H, Jones, Isabel J, Jocque, Merlijn, La, Diana, Cords, Olivia, Knight, Anika, Lund, Andrea, Wood, Chelsea L, Lafferty, Kevin D, Hoover, Christopher M, Collender, Phillip A, Remais, Justin V, Lopez-Carr, David, Fisk, Jonathan, Kuris, Armand M, and De Leo, Giulio A
- Subjects
Biological Sciences ,Biomedical and Clinical Sciences ,Vector-Borne Diseases ,Infectious Diseases ,Rare Diseases ,Infection ,Good Health and Well Being ,Africa South of the Sahara ,Animal Migration ,Animals ,Food Chain ,Humans ,Palaemonidae ,Schistosomiasis ,Snails ,dam ,disease control ,schistosome ,bilharzia ,biological control ,planetary health ,Medical and Health Sciences ,Evolutionary Biology ,Biological sciences ,Biomedical and clinical sciences - Abstract
Dams have long been associated with elevated burdens of human schistosomiasis, but how dams increase disease is not always clear, in part because dams have many ecological and socio-economic effects. A recent hypothesis argues that dams block reproduction of the migratory river prawns that eat the snail hosts of schistosomiasis. In the Senegal River Basin, there is evidence that prawn populations declined and schistosomiasis increased after completion of the Diama Dam. Restoring prawns to a water-access site upstream of the dam reduced snail density and reinfection rates in people. However, whether a similar cascade of effects (from dams to prawns to snails to human schistosomiasis) occurs elsewhere is unknown. Here, we examine large dams worldwide and identify where their catchments intersect with endemic schistosomiasis and the historical habitat ranges of large, migratory Macrobrachium spp. prawns. River prawn habitats are widespread, and we estimate that 277-385 million people live within schistosomiasis-endemic regions where river prawns are or were present (out of the 800 million people who are at risk of schistosomiasis). Using a published repository of schistosomiasis studies in sub-Saharan Africa, we compared infection before and after the construction of 14 large dams for people living in: (i) upstream catchments within historical habitats of native prawns, (ii) comparable undammed watersheds, and (iii) dammed catchments beyond the historical reach of migratory prawns. Damming was followed by greater increases in schistosomiasis within prawn habitats than outside prawn habitats. We estimate that one third to one half of the global population-at-risk of schistosomiasis could benefit from restoration of native prawns. Because dams block prawn migrations, our results suggest that prawn extirpation contributes to the sharp increase of schistosomiasis after damming, and points to prawn restoration as an ecological solution for reducing human disease.This article is part of the themed issue 'Conservation, biodiversity and infectious disease: scientific evidence and policy implications'.
- Published
- 2017
42. Monogenea of fishes from the lagoon flats of Palmyra Atoll in the Central Pacific
- Author
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Vidal-Martínez, Víctor Manuel, Soler-Jiménez, Lilia Catherinne, Aguirre-Macedo, Ma Leopoldina, Mclaughlin, John, Jaramillo, Alejandra G, Shaw2, Jenny C, James, Anna, Hechinger, Ryan F, Kuris, Armand M, and Lafferty, Kevin D
- Subjects
Biological Sciences ,Ecology ,Life Below Water ,Monogenea ,fish ,geographical isolation ,islands ,Indo-Pacific ,atoll ,Evolutionary Biology ,Zoology ,Evolutionary biology - Abstract
A survey of the monogeneans of fishes from the lagoon flats of Palmyra Atoll detected 16 species already reported from the Indo-West Pacific faunal region. A total of 653 individual fish from 44 species were collected from the sand flats bordering the lagoon of the atoll. Eighteen species of fish were infected with monogeneans. The monogenean species recovered were: Benedenia hawaiiensis on Acanthurus xanthopterus, Chaetodon auriga, Chaetodon lunula, Mulloidichthys flavolineatus, Pseudobalistes flavimarginatus and Rhinecanthus aculeatus; Ancyrocephalus ornatus on Arothron hispidus; Euryhaliotrema annulocirrus on Chaetodon auriga and Chaetodon lunula; Euryhaliotrema chrysotaeniae on Lutjanus fulvus; Euryhaliotrema grandis on Chaetodon auriga and Chaetodon lunula; Haliotrema acanthuri on Acanthurus triostegus; Haliotrema aurigae on Chaetodon auriga and Chaetodon lunula; Haliotrema dempsteri on Acanthurus xanthopterus; Haliotrema minutospirale on Mulloidichthys flavolineatus; Haliotrematoides patellacirrus on Lutjanus monostigma; Neohaliotrema bombini on Abudefduf septemfasciatus and Abudefduf sordidus; Acleotrema girellae and Acleotrema parastromatei on Kyphosus cinerascens; Cemocotylella elongata on Caranx ignobilis, Caranx melampygus and Caranx papuensis; Metamicrocotyla macracantha on Crenimugil crenilabris; and Pseudopterinotrema albulae on Albula glossodonta. All these monogenean-host combinations represent new geographical records. The monogenean species composition of the Palmyra Atoll is similar to that of the Hawaiian Islands. However, the number of species recovered was lower compared with other localities within the Indo-West Pacific, perhaps due to the geographical isolation of Palmyra Atoll.
- Published
- 2017
43. Understanding the charge transfer effects of single atoms for boosting the performance of Na-S batteries.
- Author
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Lei, Y-J, Lu, X, Yoshikawa, H, Matsumura, D, Fan, Y, Zhao, L, Li, J, Wang, S, Gu, Q, Liu, H-K, Dou, S-X, Devaraj, S, Rojo, T, Lai, W-H, Armand, M, Wang, Y-X, Wang, G, Lei, Y-J, Lu, X, Yoshikawa, H, Matsumura, D, Fan, Y, Zhao, L, Li, J, Wang, S, Gu, Q, Liu, H-K, Dou, S-X, Devaraj, S, Rojo, T, Lai, W-H, Armand, M, Wang, Y-X, and Wang, G
- Abstract
The effective flow of electrons through bulk electrodes is crucial for achieving high-performance batteries, although the poor conductivity of homocyclic sulfur molecules results in high barriers against the passage of electrons through electrode structures. This phenomenon causes incomplete reactions and the formation of metastable products. To enhance the performance of the electrode, it is important to place substitutable electrification units to accelerate the cleavage of sulfur molecules and increase the selectivity of stable products during charging and discharging. Herein, we develop a single-atom-charging strategy to address the electron transport issues in bulk sulfur electrodes. The establishment of the synergistic interaction between the adsorption model and electronic transfer helps us achieve a high level of selectivity towards the desirable short-chain sodium polysulfides during the practical battery test. These finding indicates that the atomic manganese sites have an enhanced ability to capture and donate electrons. Additionally, the charge transfer process facilitates the rearrangement of sodium ions, thereby accelerating the kinetics of the sodium ions through the electrostatic force. These combined effects improve pathway selectivity and conversion to stable products during the redox process, leading to superior electrochemical performance for room temperature sodium-sulfur batteries.
- Published
- 2024
44. On the Eschenauer-Gligor key predistribution scheme under on-off communication channels: The absence of isolated nodes (Extended version)
- Author
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Makowski, Armand M. and Yağan, Osman
- Subjects
Mathematics - Probability - Abstract
We consider the Eschenauer-Gligor key predistribution scheme under the condition of partial visibility with i.i.d. on-off links between pairs of nodes. This situation is modeled as the intersection of two random graphs, namely a random key graph and an Erd\H{o}s-R\'enyi (ER) graph. For this class of composite random graphs we give various improvements on a recent result by Ya\u{g}an [IEEE Transactions on Information Theory, 58(6):3821-3835, 2012] concerning zero-one laws for the absence of isolated nodes., Comment: Extended version of a paper appeared in Allerton 2015
- Published
- 2015
45. The Evolution of Popular Music: USA 1960-2010
- Author
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Mauch, Matthias, MacCallum, Robert M., Levy, Mark, and Leroi, Armand M.
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Physics - Physics and Society ,Computer Science - Sound - Abstract
In modern societies, cultural change seems ceaseless. The flux of fashion is especially obvious for popular music. While much has been written about the origin and evolution of pop, most claims about its history are anecdotal rather than scientific in nature. To rectify this we investigate the US Billboard Hot 100 between 1960 and 2010. Using Music Information Retrieval (MIR) and text-mining tools we analyse the musical properties of ~17,000 recordings that appeared in the charts and demonstrate quantitative trends in their harmonic and timbral properties. We then use these properties to produce an audio-based classification of musical styles and study the evolution of musical diversity and disparity, testing, and rejecting, several classical theories of cultural change. Finally, we investigate whether pop musical evolution has been gradual or punctuated. We show that, although pop music has evolved continuously, it did so with particular rapidity during three stylistic "revolutions" around 1964, 1983 and 1991. We conclude by discussing how our study points the way to a quantitative science of cultural change., Comment: MS: 13 pages, 6 figures; SI: 15 pages, 7 figures
- Published
- 2015
- Full Text
- View/download PDF
46. The effectiveness of cognitive behavioral therapy for insomnia on sleep outcomes in the context of pain among older adult veterans.
- Author
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Erickson, Alexander J., Rodriguez, Juan Carlos, Ravyts, Scott G., Dzierzewski, Joseph M., Fung, Constance H., Kelly, Monica R., Ryden, Armand M., Carlson, Gwendolyn C., Josephson, Karen, Mitchell, Michael N., Martin, Jennifer L., and Alessi, Cathy A.
- Subjects
INSOMNIA treatment ,SELF-evaluation ,PAIN measurement ,RESEARCH funding ,SECONDARY analysis ,INDEPENDENT living ,PREDICTION models ,INSOMNIA ,FATIGUE (Physiology) ,TREATMENT effectiveness ,RANDOMIZED controlled trials ,DESCRIPTIVE statistics ,CONTROL groups ,PRE-tests & post-tests ,SLEEP ,PAIN ,VETERANS ,COGNITIVE therapy ,SLEEP quality ,DROWSINESS ,DATA analysis software ,SYMPTOMS ,OLD age - Abstract
Background: Cognitive behavioral therapy for insomnia (CBT‐I) is the gold‐standard treatment for insomnia disorder in adults. Compared to young adults, older adults have increased risk for the development of conditions associated with chronic pain, which may impact the efficacy of CBT‐I in improving insomnia symptoms in older adults. This study evaluated the effect of participant‐rated pain on sleep‐related outcomes of a supervised, non‐clinician administered CBT‐I program in older adult patients with chronic insomnia disorder. Methods: Secondary analysis was conducted using data from a randomized controlled trial among 106 community‐dwelling older adult veterans (N = 106; mean age 72.1 years, 96% male, 78.3% White, 6.6% Hispanic, 5.7% African American) with chronic (≥3 months) insomnia disorder. Participants engaged in five sessions of manual‐based CBT‐I in individual or group format within one Department of Veterans Affairs healthcare system, provided by non‐clinician "sleep coaches" who had weekly telephone supervision by behavioral sleep medicine specialists. Insomnia symptoms (Insomnia Severity Index), perceived sleep quality (Pittsburgh Sleep Quality Index), fatigue (Flinder's Fatigue Scale), daytime sleepiness (Epworth Sleepiness Scale), and perceived pain severity (items from the Geriatric Pain Measure) were assessed at 4 time points: baseline, one‐week posttreatment, 6‐month follow‐up, and 12‐month follow‐up. Mixed effects models with time invariant and time varying predictors were employed for analyses. Results: CBT‐I improved insomnia symptoms, perceived sleep quality, fatigue, and daytime sleepiness among older veterans with chronic insomnia. Participant‐reported pain was associated with greater improvements in insomnia symptoms following CBT‐I. Pain did not affect improvements in other sleep‐related outcomes (−0.38 ≤ b ≤ 0.07, p > 0.05). Between‐subjects differences in pain, but not within‐subject changes in pain over time, appeared to play a central role in insomnia symptom improvement at posttreatment, with individuals with higher‐than‐average pain showing greater insomnia symptom improvement (ISI score reduction; −0.32 ≤ b ≤ −0.28, p ≤ 0.005). Conclusions: Pain did not meaningfully hinder the effects of CBT‐I on sleep outcomes. Among older veterans with chronic insomnia disorder, individuals with higher pain exhibited slightly greater improvement in insomnia than those with lower levels of pain. These findings suggest that experiencing pain does not impair treatment response and should not preclude older adults with insomnia from being offered CBT‐I. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Solar spectral conversion based on plastic films of lanthanide-doped ionosilicas for photovoltaics: Down-shifting layers and luminescent solar concentrators
- Author
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Cardoso, M.A., Correia, S.F.H., Frias, A.R., Gonçalves, H.M.R., Pereira, R.F.P., Nunes, S.C., Armand, M., André, P.S., de Zea Bermudez, V., and Ferreira, R.A.S.
- Published
- 2020
- Full Text
- View/download PDF
48. Science fiction: The biology of the alien in Alien
- Author
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Kuris, Armand M., primary and Luo, Mona Y., additional
- Published
- 2023
- Full Text
- View/download PDF
49. Precision mapping of snail habitat provides a powerful indicator of human schistosomiasis transmission
- Author
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Wood, Chelsea L., Sokolow, Susanne H., Jones, Isabel J., Chamberlin, Andrew J., Lafferty, Kevin D., Kuris, Armand M., Jocque, Merlijn, Hopkins, Skylar, Adams, Grant, Buck, Julia C., Lund, Andrea J., Garcia-Vedrenne, Ana E., Fiorenza, Evan, Rohr, Jason R., Allan, Fiona, Webster, Bonnie, Rabone, Muriel, Webster, Joanne P., Bandagny, Lydie, Ndione, Raphaël, Senghor, Simon, Schacht, Anne-Marie, Jouanar, Nicolas, Riveau, Gilles, and De Leo, Giulio A.
- Published
- 2019
50. ACANTHOCEPHALAN PARASITES OF THE OARFISH, REGALECUS RUSSELII (REGALECIDAE), WITH A DESCRIPTION OF A NEW SPECIES OF GYMNORHADINORHYNCHUS (ACANTHOCEPHALA : GYMNORHADINORHYNCHIDAE)
- Author
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Steinauer, Michelle L., Garcia-Vedrenne, Ana E., Weinstein, Sara B., and Kuris, Armand M.
- Published
- 2019
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