A PSF Approach to Far Field Discretization for Conformal Sources

In this paper we introduce a sampling scheme based on the application of an inverse source problem approach to the far field radiated by a conformal current source. The regularized solution of the problem requires the computation of the Singular Value Decomposition (SVD) of the relevant linear operator, leading to introduce the Point Spread Function in the observation domain, which can be related to the capability of the source to radiate a focusing beam. Then, the application of the Kramer generalized sampling theorem allows introducing a non-uniform discretization of the angular observation domain, tailored to each source geometry. The nearly optimal property of the scheme is compared with the best approximation achievable under a regularized inversion of the pertinent SVD. Numerical results for different two-dimensional curve sources show the effectiveness of the approach with respect to standard sampling approaches with uniform spacing, since it allows to reduce the number of sampling points of the far field.

A PSF Approach to Far Field Discretization for Conformal Sources

In this paper we introduce a sampling scheme based on the application of an inverse source problem approach to the far field radiated by a conformal current source. The regularized solution of the problem requires the computation of the Singular Value Decomposition (SVD) of the relevant linear operator, leading to introduce the Point Spread Function in the observation domain, which can be related to the capability of the source to radiate a focusing beam. Then, the application of the Kramer generalized sampling theorem allows introducing a non-uniform discretization of the angular observation domain, tailored to each source geometry. The nearly optimal property of the scheme is compared with the best approximation achievable under a regularized inversion of the pertinent SVD. Numerical results for different two-dimensional curve sources show the effectiveness of the approach with respect to standard sampling approaches with uniform spacing, since it allows to reduce the number of sampling points of the far field.

Molecular Detection of SARS-Cov-2 in Exhaled Breath Using a Portable Sampler

The SARS-CoV-2 pandemic has highlighted the need for improved technologies to help control the spread of contagious pathogens. While rapid point-of-need testing plays a key role in strategies to rapidly identify and isolate infectious patients, a cornerstone for any disease-control strategy, current test approaches have significant shortcomings related to assay limitations and sample type. Direct quantification of viral shedding in exhaled particles may offer a better rapid testing approach, since SARS-CoV-2 is believed to spread mainly by aerosols. It potentially measures contagiousness directly, the sample is easy to obtain, its production can be standardized between patients, and the limited sample volume lends itself to a fast and sensitive analysis. In view of these benefits, we developed and tested an approach where exhaled particles are efficiently sampled using inertial impaction in a micromachined silicon chip, followed by an in-situ RT-qPCR molecular assay to detect SARS-CoV-2 shedding. We demonstrate that sampling subjects using a one-minute breathing protocol, yields sufficient viral RNA to detect infections with a sensitivity comparable to standard sampling methods. A longitudinal study revealed clear differences in the temporal dynamics of viral load for nasopharyngeal swab, saliva, breath, and antigen tests. Overall, after an infection, the breath-based test is the first to consistently report a negative result, putatively signaling the end of contagiousness and further emphasizing the potential of this tool to help manage the spread of airborne respiratory infections.

Gradient Regularization as Approximate Variational Inference

We developed Variational Laplace for Bayesian neural networks (BNNs), which exploits a local approximation of the curvature of the likelihood to estimate the ELBO without the need for stochastic sampling of the neural-network weights. The Variational Laplace objective is simple to evaluate, as it is the log-likelihood plus weight-decay, plus a squared-gradient regularizer. Variational Laplace gave better test performance and expected calibration errors than maximum a posteriori inference and standard sampling-based variational inference, despite using the same variational approximate posterior. Finally, we emphasize the care needed in benchmarking standard VI, as there is a risk of stopping before the variance parameters have converged. We show that early-stopping can be avoided by increasing the learning rate for the variance parameters.

Missing the Poor, Big Time: A Critical Assessment of the Consumer Pyramids Household Survey

India’s statistical system is in bad shape with a near absence of regular publicly funded household surveys in recent years. All eyes have now turned to the Consumer Pyramids Household Survey (CPHS), a panel survey of over 170,000 households, privately executed by the Centre for Monitoring Indian Economy (CMIE) since 2014. Given its breadth and high frequency, CPHS has become a widely referenced barometer of the Indan economy. Research papers using CPHS have also mushroomed. However, there has been little validation of the nature and quality of CPHS data. Most crucially, is it true that CPHS is an “all-India representative survey” as claimed by CMIE and echoed by multiple articles in prestigious journals? Comparing CPHS with various national surveys on a set of key demographic and economic indicators, this paper argues that, far from being nationally representative, CPHS under-represents women and young children, over-represents well-educated households and under-represents the poor. A possible source for these biases (among others) is the strange, unorthodox sampling design adopted by CMIE, which differs from standard sampling approaches on various counts. Further, the bias in the CPHS sample appears to be growing in recent years, posing a serious challenge when using the data to study trends over time

Scenario generation by selection from historical data

In this paper, we present and compare several methods for generating scenarios for stochastic-programming models by direct selection from historical data. The methods range from standard sampling and k-means, through iterative sampling-based selection methods, to a new moment-based optimization approach. We compare the models on a simple portfolio-optimization model and show how to use them in a situation when we are selecting whole sequences from the data, instead of single data points.

Cardinality estimation for random stopping sets based on Poisson point processes

We construct unbiased estimators for the distribution of the number of vertices inside random stopping sets based on a Poisson point process. Our approach is based on moment identities for stopping sets, showing that the random count of points inside the complement of a stopping set S has a Poisson distribution conditionally to S. The proofs do not require the use of set-indexed martingales, and our estimators have a lower variance when compared to standard sampling. Numerical simulations are presented for examples such as the convex hull and the Voronoi flower of a Poisson point process, and their complements.

Safe and Efficient Practice of Bronchoscopic Sampling from Mechanically Ventilated Patients: A Structured Evaluation of the Ambu Bronchosampler-Ascope 4 Integrated System

<b><i>Background:</i></b> Bronchoscopic sampling of bronchoalveolar fluid (BAL) should be safe and effective. Current sampling practice risks loss of sample to the attached negative flow, aerosolisation, or spillage, due to repeated circuit breaks, when replacing sample containers. Such concerns were highlighted during the recent coronavirus pandemic. <b><i>Objectives:</i></b> Evaluation of an alternative integrated sampling solution, with the Ambu Bronchosampler with aScope 4, by an experienced bronchoscopist in ICU. <b><i>Methods:</i></b> An observational study of 20 sequential bronchoscopic diagnostic sampling procedures was performed on mechanically ventilated patients with suspected ventilator-associated pneumonia. Mixed methods assessment was done. The predefined outcome measures were (1) ease of set up, (2) ease of specimen collection, (3) ease of protecting specimen from loss or spillage, and (4) overall workflow. The duration of the procedure and the % volume of sample retrieved were recorded. <b><i>Results:</i></b> The mean (±standard deviation [SD]) time for collecting 1 sample was 2.5 ± 0.8 min. The mean (±SD) specimen yield for instilled miniBAL was 54.2 ± 17.9%. Compared with standard sampling, the set-up was <i>much easier</i> in 18 (90%), or <i>easier</i> in 2 (10%) of procedures, reducing the connection steps. It was <i>much more</i> intuitive to use in 14 (70%), <i>more</i> intuitive in 4 (20%), and <i>no more</i> intuitive to use in 2 (10%). The overall set-up and workflow was <i>much easier</i> in 69% of the 13 intraprocedural connections and <i>easier</i> or <i>as easy</i> in the remaining 31% procedures. All procedures where pre connection was established were <i>much easier</i> (7, 100%). The Ambu Bronchosampler remained upright in all procedures with no loss or spillage of sample. Obtaining a sample was <i>much easier</i> in 60%, <i>easier</i> in 10%, <i>no different</i> in 20%, and <i>worse</i> in 10%. The ability to protect a sample from start to finish compared to standard procedures was <i>much easier</i> in 80%, <i>easier</i> in 15%, and <i>no different</i> in 5% of procedures. Overall workflow was <i>much easier</i> in 14 (70%), <i>easier</i> in 4 (20%), and <i>no different</i> in 2 (10%) of procedures. <b><i>Conclusions:</i></b> The Ambu Bronchosampler unit was a reliable, effective, and possibly safer technique for diagnostic sampling in ICU. It may improve safety standards during the coronavirus pandemic. A randomized control trial against the standard sampling technique is warranted.

Regulasi Diri Sebagai Prediktor Stres Akademik Mahasiswa Bekerja Paruh Waktu

ABSTRAK: Proses pengerjaan skripsi bukanlah suatu yang mudah dilalui mahasiswa dan banyak kendala yang dihadapi, apalagi untuk mahasiswa yang sedang mengerjakan skripsi yang bekerja paruh waktu. Tekanan-tekanan dan harapan yang berhubungan dengan penyelesaian skripsi merupakan salah satu sumber stres yang sering dialami oleh mahasiswa. Stres pada mahasiswa yang mengerjakan skripsi termasuk stres akademik. Stres akademik pada mahasiswa yang bekerja paruh waktu dapat menganggu proses penyelesaian skripsi. Beberapa penelitian menyebutkan bahwa regulasi diri menjadi salah satu bentuk strategi coping stres untuk mencegah timbulnya stres akademik. Penelitian ini bertujuan untuk mengetahui hubungan antara regulasi diri dengan stres akademik pada mahasiswa skripsi Universitas Negeri Malang yang bekerja paruh waktu. Subjek dipilih menggunakan metode proporsional stratisfied sampling, dengan kriteria mahasiswa skipsi Universitas Negeri Malang yang bekerja paruh waktu. Subjek penelitian berjumlah 43 mahasiswa. Instrumen Regulasi Diri memiliki reliabilitas 0,888 dan Skala Stres Akademik adaptasi dari Lin dan Chen (2009) memiliki reliabilitas 0,826. Menggunakan analisis korelasi product moment pearson dan analisis regresi sederhana diperoleh hasil bahwa terdapat hubungan negatif antara regulasi diri dengan stres akademik pada mahasiswa skripsi Universitas Negeri Malang. Sumbangan pengaruh regulasi diri terhadap stres akademik sebesar 21,3% sisanya dipengaruhi oleh faktor lain. Kata Kunci: regulasi diri; stres akademik ABSTRACT: The thesis process is not an easy thing for a student to pass and many obstacles are encountered, especially for thesis students who work part time. Pressures and expectations related to the completion of the thesis is one source of stress that is often experienced by students. Stress on students working on their thesis, including academic stress. Academic stress on undergraduate students who work part-time can disrupt the process of completion of the thesis. Some studies suggest that self-regulation is a form of stress coping strategy to prevent academic stress. This study aims to determine the relationship between self-regulation and academic stress in undergraduate thesis students of Malang State University who work part time. Subjects were selected using the proportional standard sampling method, with the criteria for students of Malang State University who work part time. Research subjects were 43 students. The Self Regulatory Instrument has a reliability of 0.888 and the Academic Stress Adaptation Scale from Lin and Chen (2009) has a reliability of 0.826. Using Pearson product moment correlation analysis and simple regression analysis results show that there is a negative relationship between self-regulation and academic stress on undergraduate students at State University of Malang. The contribution of self-regulation to academic stress by the remaining 21.3% is influenced by other factors. Keyword: self regulation; academic stress

TO CORRELATE BETWEEN BIOCHEMICAL PARAMETERS AND DIFFERENT GRADES OF OBESITY

Background & Method: In this case control (observational) study we include 114 participant (n=57 cases and n=57 controls) in this case and controls taken using standard sampling procedure participants are taken who attend Medicine OPD in Netaji Subhash Chandra Bose Medical college Jabalpur in period of March 2015 to August 2016. Result: We didn’t found significant difference in cases on the basis of BMI and FBS,PPBS and GTT.We found correlation in cases on the basis of BMI and in Lipid Profile and we found there is significant difference in low density lipid level in overweight and moderate obese (t>2.08) and Triglyceride level and Serum cholesterol/HDL ratio in overweight and sever obese (t>1.97, t>2.41) and moderate and severe Obese (t>2.14, t>2.10). Conclusion: In cases on the basis of Diastolic dysfunction and Lipid Profile we found significant difference between serum cholesterol/HDL levels in those who had Diastolic dysfunction compare to who don’t have Diastolic dysfunction. Diastolic dysfunction appears not to be influenced by sex. The association between diastolic dysfunction and obesity according to sex is not significant. In cases on the basis of BMI and FBS, PPBS and GTT we don’t found significant difference in cases. In grades of Diastolic Dysfunction and Lipid profile and we doesn’t found any significant difference in grade 1 and grade 2 diastolic dysfunction on the basis of lipid profile. Keywords: BMI, Left Ventricular, Transthoracic & Echocardiography.