Search

Machine learning (ML) solutions to indoor localization problems have become popular in recent years due to high positioning accuracy and low cost of implementation. This paper proposes a novel local nonparametric approach for solving localizations from high-dimensional Received Signal Strength Indicator (RSSI) values. Our approach consists of a sequence of classification algorithms that sequentially narrows down the possible space for location solutions into smaller neighborhoods. The idea of this sequential classification method is similar to the decision tree algorithm, but a key difference is our splitting of the dataset at each node is not based on features of input (i.e. RSSI values), but some discrete-valued variables generated from the output variable (i.e. the 3D real-world coordinates). The strength of our localization solution can be tuned to problem specifics by the appropriate choice of how to sequentially partition the the space of location into smaller neighborhoods. Using the publicly available indoor localization dataset UJIIndoorLoc, we evaluate our proposed method vs. the global ML algorithms for the dataset. The primary contribution of this paper is to introduce a novel local ML solution for indoor localization problems., To be published in IEEE SoutheastCon 2023 conference proceedings

Background Chest X-rays (CXRs) are often requested for patients who present to emergency with abdominal pain, but its benefit to patient management remains unclear. Several guidelines have been developed to ensure that imaging investigations have the highest diagnostic impact. This study aims to compare referral guidelines to establish their recommendations and circumstances for recommendations regarding CXRs for patients with abdominal pain. Methods A systematic search of the literature was performed using Medline (via OVID), PubMed, Google, and Google Scholar. Referral guidelines were included if they provided recommendations for imaging of abdominal pain, were based on published evidence, and were broadly utilised. Data related to their recommendations for CXR for abdominal pain was recorded and analysed. Results Three guidelines supported the use of CXRs in the case of suspected perforation. Two guidelines included CXR for patients presenting with blunt abdominal trauma and severe abdominal pain requiring admission. One of the guidelines included use of CXRs for patients presenting with suspected small bowel obstruction, cholecystitis, and penetrating trauma. Two guidelines recorded no circumstances where the use of CXRs were recommended. Conclusion Published evidence-based guidelines allow for the use of CXRs for patients presenting with abdominal pain in very limited circumstances.

Exponential increases in anthropogenic noise and night lighting have accompanied growth of the built environment. Noise and night lighting cause negative consequences for birds, such as disrupted navigation during migration, mortality from collisions with windows and other infrastructure, and reduced reproductive success, as well as some positive consequences, such as expanded night niches for behaviors associated with feeding, territoriality, and mating. Relatively less is known about noise and light effects on avian annual survival of non-migratory birds, so we carried out an exploratory study to examine variation in adult survival rates of seven avian species in relation to noise and light pollution. We used 20 years of band-resight data collected as a part of the Neighborhood Nestwatch Program (NN), a citizen science project run by the Smithsonian Migratory Bird Center, at 242 sites in greater Washington, D.C. USA. We estimated apparent survival and documented species-specific relationships with light and noise. Gray Catbird (Dumetella carolinensis) and House Wren (Thryothorus aedon) survival decreased and American Robin (Turdus migratorius) survival increased with greater amounts of anthropogenic light. Anthropogenic noise had no relationship with apparent survival for any of the seven species. Life-history trade-offs between survival and reproduction may account for differences in species-specific effects of light pollution. Future research should examine the availability of other fine scale environmental conditions, such as tree canopy cover, that might buffer avian exposure to noise and light pollution.

In this paper, we investigate multicell-coordinated beamforming for large-scale multiple-input multipleoutput (MIMO) orthogonal frequency-division multiplexing (OFDM) communications with low-resolution data converters. In particular, we seek to minimize the total transmit power of the network under received signal-to-quantization-plus-interference-and-noise ratio constraints while minimizing per-antenna transmit power. Our primary contributions are (1) formulating the quantized downlink (DL) OFDM antenna power minimax problem and deriving its associated dual problem, (2) showing strong duality and interpreting the dual as a virtual quantized uplink (UL) OFDM problem, and (3) developing an iterative minimax algorithm to identify a feasible solution based on the dual problem with performance validation through simulations. Specifically, the dual problem requires joint optimization of virtual UL transmit power and noise covariance matrices. To solve the problem, we first derive the optimal dual solution of the UL problem for given noise covariance matrices. Then, we use the solution to compute the associated DL beamformer. Subsequently, using the DL beamformer we update the UL noise covariance matrices via subgradient projection. Finally, we propose an iterative algorithm by repeating the steps for optimizing DL beamformers. Simulations validate the proposed algorithm in terms of the maximum antenna transmit power and peak-to-average-power ratio., submitted for possible IEEE journal publication

Accurate sand flow rate measurement is needed to minimize the side effects of sand production in gas fields. There are concerns about the accuracy of sand flow measurement using the sand measuring devices available on the market. In this paper, ultrasonic sensors and discrete wavelet transform signal analysis method is used to measure the sand flow rate. It is found that the strength of the discrete wavelet coefficients in the frequency range of 15–62 kHz has a linear relationship with sand flow rate. This finding provides a new methodology to accurately measure sand flow rate. The proposed method does not need fluid velocity as a prerequisite for sand rate measurement, so it greatly simplifies the system design when flow meters are not used for fluid velocity measurement. Also, this method has a much simpler calibration procedure compared to that of the sand detectors commonly used in the industry.

Production of sand in gas wells is associated with various issues such as the erosion of pipes, disruption of the gas processing plant and reduced production capacity. Sand production can jeopardise the integrity of the pipes/equipment. Measuring the sand flow rate helps better sand control and management. Currently, there are many concerns about the accuracy of sand flow rate measurement using a commercial acoustic sand detector (ASD). This study suggests a relationship which substantially improves the accuracy of sand flow rate measurement using an ASD. This study also investigates using a simple ultrasonic sensor for sand flow rate measurement in which a fast Fourier transform (FFT) is used to convert data into the frequency domain. When a Savitzky–Golay filter is used on the FFT response, the smoothed output shows that there is a close relationship between the peak value of smoothed FFT signal in the 10–50 kHz frequency range, and the sand flow rate. This relationship provides a more accurate measurement of sand flow rate than is presently available using an ASD.

Rapid, facile, and noncovalent cell membrane modification with alkyl-grafted anionic polymers was sought as an approach to enhance intracellular delivery and bioactivity of cationic peptides. We synthesized a library of acrylic acid-based copolymers containing varying amounts of an amine-reactive pentafluorophenyl acrylate monomer followed by postpolymerization modification with a series of alkyl amines to afford precise control over the length and density of aliphatic alkyl side chains. This synthetic strategy enabled systematic investigation of the effect of the polymer structure on membrane binding, potentiation of peptide cell uptake, pH-dependent disruption of lipid bilayers for endosome escape, and intracellular bioavailability. A subset of these polymers exhibited pK(a) of ~6.8, which facilitated stable membrane association at physiological pH and rapid, pH-dependent endosomal disruption upon endocytosis as quantified in Galectin-8-YFP reporter cells. Cationic cell penetrating peptide (CPP) uptake was enhanced up to 15-fold in vascular smooth muscle cells in vitro when peptide treatment was preceded by a 30-min pretreatment with lead candidate polymers. We also designed and implemented a new and highly sensitive assay for measuring the intracellular bioavailability of CPPs based on the NanoLuciferase (NanoLuc) technology previously developed for measuring intracellular protein–protein interactions. Using this split luciferase class of assay, polymer pretreatment enhanced intracellular delivery of the CPP-modified HiBiT peptide up to 30-fold relative to CPP-HiBiT without polymer pretreatment (p < 0.05). The overall structural analyses show that polymers containing 50:50 or 70:30 molar ratios of carboxyl groups to alkyl side chains of 6–8 carbons maximized peptide uptake, pH-dependent membrane disruption, and intracellular bioavailability and that this potentiation effect was maximized by pairing with CPPs with high cationic charge density. These results demonstrate a rapid, mild method for polymer modification of cell surfaces to potentiate intracellular delivery, endosome escape, and bioactivity of cationic peptides.

Background and aim Atrial septal defects with anomalous venous connections are commonly repaired via sternotomy, requiring careful baffle reconstruction to redirect pulmonary venous return and ensure a durable result. The cosmetically appealing periareolar incision may provide an esthetically superior alternative to the anterolateral minithoracotomy incision used in minimally invasive cardiac surgery. Methods We describe a patient with a sinus venosus atrial septal defect and partial anomalous pulmonary venous connection who underwent successful minimally invasive, endoscopic repair with apical vein translocation and autologous pericardial baffle reconstruction through a periareolar approach. Results Post-operative echocardiography demonstrated excellent results with no residual shunt and a widely patent baffle and preserved biventricular function. At 1-year post-op, our patient has had a greatly improved quality of life and an excellent cosmetic result with normal nipple-areolar sensation. Conclusions We believe that periareolar approaches should be considered for all adult patients with simple and complex atrial septal defects.

Semi-brittle flow occurs when crystal plasticity and cataclastic mechanisms operate concurrently and may be common in the middle Earth’s crust. To better constrain the characteristics of semi-brittle deformation, we performed triaxial tests up to 12% strain on dry samples of Carrara marble, spanning a wide range of temperature (T = 20 - 800°C), confining pressures (PC = 30 – 300 MPa), and strain rates (ε'= 10-3 - 10­-6 s-1). The (differential) stress (Δσ = σ1 - PC) and the hardening coefficient (h = ∂Δσ/∂ε ) depend on the applied conditions. At most conditions, Δσ increases with strain, whereas h decreases with increasing strain. At 5% strain, stress and the hardening coefficient increase as T decreases and PC increases: Remarkably, both are relatively insensitive to temperature and to rate in the range of ≈ 200 < T < 400°C. At T ≲ 400°C, the mechanical behavior of the marble is very similar to that exhibited by high-strength, high-ductility, hexagonal metals that deform by processes called twinning induced plasticity (TWIP). Qualitative microstructural observations show that twinning, dislocation motion, and inter- and intra-crystalline micro-fractures are abundant in the deformed samples over the entire range of conditions. The interplay of these deformation mechanisms leads to complex relationships of Δσ and h with the applied ε' - T ‑ PC ‑ conditions. Models for TWIP behavior suggest that hardening increases with decreasing twin spacing and increasing dislocation density. The low sensitivity of Δσ and h to T at 200 to 400°C may be explained by the relatively low temperature sensitivity of the critical resolved shear stress for twinning and dislocation slip in calcite in this range. None of the existing models for the brittle-ductile transition or the brittle-plastic transition are able to fully predict our experimental results, and micro mechanism-based constitutive laws for semi-brittle deformation are missing so far. Nevertheless, our observations suggest that peak strengths for calcite rocks deforming by semi-brittle processes will occur at PC ‑ T conditions of the middle crust, but that the strengths are probably more strongly influenced by total strain rather than by strain rate.

We propose an adaptive learning-based framework for uplink massive multiple-input multiple-output (MIMO) systems with one-bit analog-to-digital converters. Learning-based detection does not need to estimate channels, which overcomes a key drawback in one-bit quantized systems. During training, learning-based detection suffers at high signal-to-noise ratio (SNR) because observations will be biased to +1 or -1 which leads to many zero-valued empirical likelihood functions. At low SNR, observations vary frequently in value but the high noise power makes capturing the effect of the channel difficult. To address these drawbacks, we propose an adaptive dithering-and-learning method. During training, received values are mixed with dithering noise whose statistics are known to the base station, and the dithering noise power is updated for each antenna element depending on the observed pattern of the output. We then use the refined probabilities in the one-bit maximum likelihood detection rule. Simulation results validate the detection performance of the proposed method vs. our previous method using fixed dithering noise power as well as zero-forcing and optimal ML detection both of which assume perfect channel knowledge., Comment: 6 pages 6 figures

RESUMEN Los tumores de la región retrorrectal son lesiones poco frecuentes, con potencial de malignidad e infección. Generalmente cursan asintomáticos. Presentamos el caso de una paciente de 62 años, con dolor pélvico crónico, cuyos estudios imagenológicos informan lesión ocupante de espacio de 3 cm en región presacra. Se procedió a su resección quirúrgica con diagnostico histopatológico de schwannoma. ABSTRACT Retrorectal tumors are rare but have potential malignant transformation and risk of infection. Thet are usually asymptomatic. We report the case of a 62-year-old female patient with chronic pelvic pain and imaging tests showing a 3-cm space-occupying lesion in the presacral region. The lesion resected and the histopathologic diagnosis was schwannoma.

Semi-brittle flow occurs when crystal plasticity and cataclastic mechanisms operate concurrently and may be common at mid-levels of the Earth’s crust. Using a Paterson gas-deformation apparatus, we performed 67 conventional triaxial deformation experiments on dry samples of Carrara marble in the temperature range of T = 20 - 800°C; confining pressures (PC) were 30, 50 100, 200, and 300 MPa, and strain rates (urn:x-wiley:21699313:media:jgrb55357:jgrb55357-math-0001) were 10-3, 10-4, 10-5, and 10-6 s-1. Axial strains (ε ) were ≲ 0.12. The measured (differential) stress, urn:x-wiley:21699313:media:jgrb55357:jgrb55357-math-0002, changes with strain at most applied conditions. At ε = 0.05, both stress and the hardening coefficient (h), i.e., the rate of increase of stress with strain, increase as T decreases and PC increases. At T ≲ 400°C, h is quite large and the sensitivity of urn:x-wiley:21699313:media:jgrb55357:jgrb55357-math-0003 on urn:x-wiley:21699313:media:jgrb55357:jgrb55357-math-0004 is low, while both are sensitive to increasing pressure. In this temperature range, the mechanical behavior of the marble is very similar to that exhibited by high-strength, high-ductility, hexagonal metals that deform by processes called twinning induced plasticity (TWIP). Twinning and dislocation motion are abundant in the samples, as are inter- and intra-crystalline micro-fractures. The concurrent activation of these deformation mechanisms leads to complex relationships of urn:x-wiley:21699313:media:jgrb55357:jgrb55357-math-0005 and h with the applied T- PC - urn:x-wiley:21699313:media:jgrb55357:jgrb55357-math-0006 conditions. This behavior suggests that peak stresses for calcite rocks deforming by semi-brittle processes will occur at PC - T conditions of the middle crust, and that they might be more strongly influenced by total strain rather than by strain rate.

The displacement process of CH4 by the CO2 injection in the shale micropores plays a dominant role in the CO2 enhanced shale gas recovery (CO2-ESGR). In this paper, we have addressed the displaceme...

Graphical abstract, Highlights • CTS is characterized by a membrane that divides the left atrium into two chambers. • This patient also presented with mitral regurgitation. • The authors present multimodality images and intraoperative video clips. • In this case, repair was performed with a minimally invasive approach. • Intraoperative echocardiography is an essential element of patient care.

The twenty-first century is the era when populations of cities will exceed rural communities for the first time in human history. The population growth of cities in many countries, including those in transition from planned to market economies, is putting considerable strain on ecological and natural resources. This paper examines four central issues: (a) the challenges and opportunities presented through working in jurisdictions where there are no official or established methods in place to guide regional, ecological and landscape planning and design; (b) the experience of the author’s practice—Gillespies LLP—in addressing these challenges using techniques and methods inspired by McHarg in Design with Nature in the Russian Federation in the first decade of the twenty-first century; (c) the augmentation of methods derived from Design with Nature in reference to innovations in technology since its publication and the contribution that the art of landscape painters can make to landscape analysis and interpretation; and (d) the application of this experience to the international competition and colloquium for the expansion of Moscow. The text concludes with a comment on how the application of this learning and methodological development to landscape and ecological planning and design was judged to be a central tenant of the winning design. Finally, a concluding section reflects on lessons learned and conclusions drawn.

To this day, tissue reconstruction and replacement to address extensive tissue defects due to trauma, tumor resection, genetic and/or chronic diseases, or excessive debridement present a major clinical challenge. Traditional reconstructive techniques most commonly utilize autologous tissue. Undoubtedly, autologous composite tissue transfers or “flaps,” skin grafts, as well as the harvesting of bone and/or cartilage have substantially improved the health, functional, and aesthetic outcomes of millions of patients. Unfortunately, these procedures are not without their drawbacks. These include increased operative time, complexity, cost, limited availability of qualitative autologous tissue, wound healing complications, tissue flap failure, and substantial donor-site morbidity. Recently, collaborative research teams—consisting of surgeons, scientists, and engineers—have made substantial progress in their attempts to solve these problems. This article provides historical perspective, covers the major limitations of current standards of care, and reviews recent advances and future prospects in applied bioengineering in the context of tissue reconstruction, replacement, and regeneration. IMPACT STATEMENT: The use of autologous tissue in the reconstruction of tissue defects has been the gold standard. However, current standards still face many limitations and complications. Improving patient outcomes and quality of life by addressing these barriers remain imperative. This article provides historical perspective, covers the major limitations of current standards of care, and reviews recent advances and future prospects in applied bioengineering in the context of tissue reconstruction, replacement, and regeneration.

The Kyoto Protocol defines new emissions standards to be met by the international community in respect of greenhouse gases, the aim of which is to curb the present trend of adverse climate change. The specific responses of ratifying governments to bring about the desired changes will significantly impact citizenry and industry alike. This article addresses the issues surrounding emissions trading systems as market-based policy instruments that may ultimately contribute to Canada s legislative response to the Kyoto standards. Central to this question is the need to familiarize legal practitioners with the implications of climate change and the range of policy responses available to government in the context of emissions trading systems. The author examines responses open to the governments of Canada and Alberta through a review of the international reaction to climate change, the role of emissions trading in environmental regulation generally and the anticipated use of emissions trading to comply with the Kyoto Protocol in the future. The author presents an in-depth analysis of the principles underlying the design of domestic emissions trading systems, of the legislative authority surrounding their implementation and of the need for affected businesses to strategically plan for ensuing changes. The author concludes that while Canada has not yet adopted a policy on domestic emissions trading systems in respect of the Kyoto Protocol, the potential impact of emission standards on domestic sources is pronounced, meriting an inspection of the design features that may form a pan of such trading schemes.

Todays healthcare environment is competitive enough without an incident interrupting one's organization s operations. Incidents can be expensive to organizations in terms of system downtime, labor costs, fines and penalties, or loss of reputation. Patients can be adversely affected as well, with an incident resulting in delayed or interrupted healthcare delivery, identity theft, or embarrassment from a breach with their patient data. When organizations put forth the effort, they quickly find there are low-cost, high-impact incident response solutions available to them. An incident can be defined as any event, actual or suspected to have occurred, which destroys or degrades the availability, integrity, and confidentiality of information system resources, computer-based systems, computer-maintained data files, documents or procedures. The National Institute of Standards and Technology’s Computer Security Incident Handling Guide is an excellent benchmark to measure against because it is an up-to-date, relevant best practice reference.

Vascular procedures, such as stenting, angioplasty, and bypass grafting, often fail due to intimal hyperplasia (IH), wherein contractile vascular smooth muscle cells (VSMCs) dedifferentiate to synthetic VSMCs, which are highly proliferative, migratory, and fibrotic. Previous studies suggest MAPK-activated protein kinase 2 (MK2) inhibition may limit VSMC proliferation and IH, although the molecular mechanism underlying the observation remains unclear. We demonstrated here that MK2 inhibition blocked the molecular program of contractile to synthetic dedifferentiation and mitigated IH development. Molecular markers of the VSMC contractile phenotype were sustained over time in culture in rat primary VSMCs treated with potent, long-lasting MK2 inhibitory peptide nanopolyplexes (MK2i-NPs), a result supported in human saphenous vein specimens cultured ex vivo. RNA-Seq of MK2i-NP-treated primary human VSMCs revealed programmatic switching toward a contractile VSMC gene expression profile, increasing expression of antiinflammatory and contractile-associated genes while lowering expression of proinflammatory, promigratory, and synthetic phenotype-associated genes. Finally, these results were confirmed using an in vivo rabbit vein graft model where brief, intraoperative treatment with MK2i-NPs decreased IH and synthetic phenotype markers while preserving contractile proteins. These results support further development of MK2i-NPs as a therapy for blocking VSMC phenotype switch and IH associated with cardiovascular procedures.

BACKGROUND: There is a correlation between the sites of atheroma development and stress points in the arterial system. Generally, pulse pressure results in stresses acting on the vascular vessel, including longitudinal stress, radial or normal stress, tangential stress or hoop stress and shear stress. This paper explores the relationship between arterial wall shear stress and pulsatile blood pressure with the aim of furthering the understanding of atherogenesis and plaque progression. METHODS: We computed the magnitude of the shear stresses within the carotid bifurcation geometry of a patient and calculated the increase in shear stress levels that would occur when the blood pressure and pulse pressures rise during exertion. We also determined in which layer of the artery wall the maximum shear stress is located, and computed the shear stress at different levels within the media. We used the theory of laminate analysis, (Classical Laminate Plate Theory), to analyse the stress distribution on the carotid artery wall. Computational Fluid Dynamics (CFD) analysis was used on anatomy based on a CT angiogram of the carotid bifurcation of a patient with a 90% stenosis on the right side and 10% on the left. The pulsatile non-Newtonian blood flow with a resting blood pressure of 120/80 mmHg and an exertion pressure of 200/100 mmHg was simulated and the resultant forces were transferred to an ANSYS Composite PrepPost (ACP) model for wall shear stress analysis. A multilayer elastic, anisotropic, and inhomogeneous arterial wall (intima, internal elastic lamina, media, external elastic lamina, and adventitial layers) was modelled and the shear stress magnitudes and change over time between the layers was calculated. RESULTS: Shear stress in the individual composite layers is far greater than that acting on the endothelium (less than 5 Pa). At rest, the maximum variation of shear stress in the arterial wall occurs in the intima (138 Pa) and adventitia (135 Pa). The medial layer has the lowest variation of shear stress. Under severe exertion, the maximum shear stress magnitude in the intimal layer and the adjacent medial layer is near the ultimate stress level. The maximum/minimum shear stress ratios during the cardiac cycle vary most widely in the innermost part of the media, adjacent to the intima, with a four-fold ratio increase. This compares with a less than two-fold increase in all the other layers including the intima and adventitia, making the inner media the most vulnerable layer to mechanical injury. CONCLUSIONS: This study showed that the magnitude of exertion-induced shear stress approaches the ultimate stress limit in the intima and the immediate adjacent medial layer. The variation in stress is maximal in the inner layer of the media. These findings correlate the site of atheroma development with the most vulnerable site for injury in the media and emphasise the impact of pulse pressure. Further biological studies are required to ascertain whether this leads to injury that initiates atheroma that then precipitates an injury/healing cycle.

It is generally accepted that drilling with drag bits (Polycrystalline Diamond Compact bits) simultaneously consists of “pure cutting” and “frictional contact” processes. To date, the mechanics of rock cutting have been mostly based on the assumption that these two processes are fully independent as the influence of wear flat inclination angle (β) with respect to the cutter velocity vector ( v ) on the frictional contact force is often not accounted for. The specific aim of this study is to determine the effect of wear flat inclination angle on the frictional force acting on the wear flat surface of a single blunt cutter over a wide range of depths of cut (d). For this purpose, an extensive and comprehensive set of cutting experiments was performed on two sedimentary rock samples (a limestone and a sandstone) using a state-of-the-art rock cutting equipment and a unique cutter holder. The results show that the normal contact stress (σ) at the wear flat-rock interface (and therefore the normal frictional force acting on the wear flat) is dependent on the depth of cut within the elastoplastic and particularly plastic regimes of frictional contact; however, the contact stress is invariant with depth of cut within the elastic regime. Further investigations indicate that the assumption that the force acting on the wear flat surface of a blunt cutter is independent of the cutting process taking place ahead of the cutter is not valid in particular, for the large values of inclination angles.

The objective of this paper is to investigate the influence of the rake angle on the magnitude of the intrinsic specific energy and the inclination of the force acting on the cutting face of a Polycrystalline Diamond Compact (PDC) sharp cutter while tracing a groove on the surface of a rock sample. An extensive and comprehensive set of cutting experiments was performed on a wide range of quarry rock samples using a state of the art rock cutting equipment (Wombat). The results conform with the previous studies by other researchers; the intrinsic specific energy is in good agreement with the uni-axial compressive strength of the rock samples when the cutter is positioned at back rake angles between 5° to 20°. New results on a few rock samples were also obtained by performing novel experimental tests at very large rake angles ( θ > 70 ° ) as well as negative rake angles, showing that the intrinsic specific energy increases dramatically once the back rake angle exceeds 75°. Results also indicate that the decrease of the apparent interfacial friction angle with increasing back rake angle seems to follow a “universal trend” weakly dependent on the rock sample.