Application of Artificial Neural Network to Search for Gravitational-Wave Signals Associated with Short Gamma-Ray Bursts

We apply a machine learning algorithm, the artificial neural network, to the search for gravitational-wave signals associated with short gamma-ray bursts. The multi-dimensional samples consisting of data corresponding to the statistical and physical quantities from the coherent search pipeline are fed into the artificial neural network to distinguish simulated gravitational-wave signals from background noise artifacts. Our result shows that the data classification efficiency at a fixed false alarm probability is improved by the artificial neural network in comparison to the conventional detection statistic. Therefore, this algorithm increases the distance at which a gravitational-wave signal could be observed in coincidence with a gamma-ray burst. In order to demonstrate the performance, we also evaluate a few seconds of gravitational-wave data segment using the trained networks and obtain the false alarm probability. We suggest that the artificial neural network can be a complementary method to the conventional detection statistic for identifying gravitational-wave signals related to the short gamma-ray bursts.Comment: 30 pages, 10 figure

Effect of care environment on educational attainment among orphaned and separated children and adolescents in Western Kenya

Background: There are approximately 140 million orphaned and separated children (OSCA) around the world. In Kenya, many of these children live with extended family while others live in institutions. Despite evidence that orphans are less likely to be enrolled in school than non-orphans, there is little evidence regarding the role of care environment. This evidence is vital for designing programs and policies that promote access to education for orphans, which is not only their human right but also an important social determinant of health. The purpose of this study was to compare educational attainment among OSCA living in Charitable Children’s Institutions and family-based settings in Uasin Gishu County, Kenya. Methods: This study analyses follow up data from a cohort of OSCA living in 300 randomly selected households and 17 institutions. We used Poisson regression to estimate the effect of care environment on primary school completion among participants age ≥ 14 as well as full and partial secondary school completion among participants age ≥ 18. Risk ratios and 95% confidence intervals were estimated using a bootstrap method with 1000 replications. Results: The analysis included 1406 participants (495 from institutions, 911 from family-based settings). At baseline, 50% were female, the average age was 9.5 years, 54% were double orphans, and 3% were HIV-positive. At follow- up, 76% of participants age ≥ 14 had completed primary school and 32% of participants age ≥ 18 had completed secondary school. Children living in institutions were significantly more likely to complete primary school (aRR: 1.18, 95% CI: 1.10–1.28) and at least 1 year of secondary school (aRR: 1.28, 95% CI: 1.18–1.39) than children in family-based settings. Children living in institutions were less likely to have completed all 4 years secondary school (aRR: 0.79, 95% CI: 0.43–1.18) than children in family-based settings. Conclusion: Children living in institutional environments were more likely to complete primary school and some secondary school than children living in family-based care. Further support is needed for all orphans to improve primary and secondary school completion. Policies that require orphans to leave institution environments upon their eighteenth birthday may be preventing these youth from completing secondary school

Optimizing Parameters of Information-Theoretic Correlation Measurement for Multi-Channel Time-Series Datasets in Gravitational Wave Detectors

Data analysis in modern science using extensive experimental and observational facilities, such as a gravitational wave detector, is essential in the search for novel scientific discoveries. Accordingly, various techniques and mathematical principles have been designed and developed to date. A recently proposed approximate correlation method based on the information theory is widely adopted in science and engineering. Although the maximal information coefficient (MIC) method remains in the phase of improving its algorithm, it is particularly beneficial in identifying the correlations of multiple noise sources in gravitational-wave detectors including non-linear effects. This study investigates various prospects for determining MIC parameters to improve the reliability of handling multi-channel time-series data, reduce high computing costs, and propose a novel method of determining optimized parameter sets for identifying noise correlations in gravitational wave data.Comment: 11 pages, 8 figure

Cost Utility of Supporting Family-Based Care to Prevent HIV and Deaths among Orphaned and Separated Children in East Africa: A Markov Model–Based Simulation

Purpose: Strengthening family-based care is a key policy response to the more than 15 million orphaned and separated children who have lost 1 or both parents in sub-Saharan Africa. This analysis estimated the cost-effectiveness of family-based care environments for preventing HIV and death in this population. Design: We developed a time-homogeneous Markov model to simulate the incremental cost per disability-adjusted life year (DALY) averted by supporting family-based environments caring for orphaned and separated children in western Kenya. Model parameters were based on data from the longitudinal OSCAR’s Health and Well-Being Project and published literature. We used a societal perspective, annual cycle length, and 3% discount rate. Incremental cost-effectiveness ratios were simulated over 5- to 15-y horizons, comparing family-based settings to street-based “self-care.” Parameter uncertainty was addressed via deterministic and probabilistic sensitivity analyses. Results: Under base-case assumptions, family-based environments prevented 422 HIV infections and 298 deaths in a simulated cohort of 1,000 individuals over 10 y. Compared with street-based self-care, family-based care had an incremental cost of $2,528 per DALY averted (95$2,355 per quality-adjusted life year gained (95% CI: 1,667, 2,413). The probability of family-based care being highly cost-effective was \u3e80% at a willingness-to-pay (WTP) threshold of $2,250/DALY averted. Households receiving government cash transfers had minimally higher cost-effectiveness ratios than households without cash transfers but were still cost-effective at a WTP threshold of twice Kenya’s GDP per capita. Conclusions: Compared with the status quo of street-based self-care, family-based environments offer a cost-effective approach for preventing HIV and death among orphaned children in lower-middle income countries. Decision makers should consider increasing resources to these environments in tandem with social protection programs

Association of Care Environment With HIV Incidence and Death Among Orphaned, Separated, and Street-Connected Children and Adolescents in Western Kenya

Importance: In 2015, there were nearly 140 million orphaned children globally, particularly in low- and middle-income regions, and millions more for whom the street is central to their everyday lives. A total of 16.6 million children were orphaned because of deaths associated with HIV/AIDS, of whom 90% live in sub-Saharan Africa. Although most orphaned and separated children and adolescents in this region are cared for by extended family, the large number of children requiring care has produced a proliferation of institutional care. Few studies have investigated the association between care environment and physical health among orphaned and separated youths in sub-Saharan Africa. Objective: To examine the association of care environment with incident HIV and death among orphaned and separated children and adolescents who were living in charitable children’s institutions, family-based settings, and street settings in western Kenya over almost 10 years. Design, Setting, and Participants: The Orphaned and Separated Children’s Assessments Related to Their Health and Well-Being (OSCAR) project was an observational prospective cohort study conducted in Uasin Gishu County, Kenya. The cohort comprised 2551 orphaned, separated, and street-connected children from communities within 8 administrative locations, which included 300 randomly selected households (family-based settings) caring for children who were orphaned from all causes, 19 charitable children’s institutions (institutional settings), and a convenience sample of 100 children who were practicing self-care on the streets (street settings). Participants were enrolled from May 31, 2010, to April 24, 2013, and were followed up until November 30, 2019. Exposures: Care environment (family-based, institutional, or street setting). Main Outcomes and Measures: Survival regression models were used to investigate the association between care environment and incident HIV, death, and time to incident HIV or death. Results: Among 2551 participants, 1230 youths were living in family-based settings, 1230 were living in institutional settings, and 91 were living in street settings. Overall, 1321 participants (51.8%) were male, with a mean (SD) age at baseline of 10.4 (4.8) years. Most participants who were living in institutional (1047 of 1230 youths [85.1%]) or street (71 of 91 youths [78.0%]) settings were double orphaned (ie, both parents had died). A total of 59 participants acquired HIV infection or died during the study period. After adjusting for sex, age, and baseline HIV status, living in a charitable children’s institution was not associated with death (adjusted hazard ratio [AHR], 0.26; 95% CI, 0.07-1.02) or incident HIV (AHR, 1.49; 95% CI, 0.46-4.83). Compared with living in a family-based setting, living in a street setting was associated with death (AHR, 5.46; 95% CI, 2.30-12.94), incident HIV (AHR, 17.31; 95% CI, 5.85-51.25), and time to incident HIV or death (AHR, 7.82; 95% CI, 3.48-17.55). Conclusions and Relevance: In this study, after adjusting for potential confounders, no association was found between care environment and HIV incidence or death among youths living in institutional vs family-based settings. However, living in a street setting vs a family-based setting was associated with both HIV incidence and death. This study’s findings suggest that strengthening of child protection systems and greater investment in evidence-based family support systems that improve child and adolescent health and prevent youth migration to the street are needed for safe and beneficial deinstitutionalization to be implemented at scale

Identifying and diagnosing coherent associations and causalities between multi-channels of the gravitational wave detector

The gravitational-wave detector is a very complicated and sensitive collection of advanced instruments, which is influenced not only by the mutual interaction between mechanical/electronics systems but also by the surrounding environment. Thus, it is necessary to categorize and reduce noises from many channels interconnected by such instruments and environment for achieving the detection of gravitational waves because it enhances to increase of a signal-to-noise ratio and reduces false alarms from coincident loud events. For this reason, it is of great importance to identify some coherent associations between complicated channels. This study presents a way of identifying (non-) linear couplings between interconnected channels by using some correlation coefficients, which are applied to practical issues such as noises by hardware injection test, lightning strokes, and air compressor vibrations gravitational-wave detector.Comment: 10 pages, 8 figures, and 2 table

Deep Learning Model on Gravitational Waveforms in Merging and Ringdown Phases of Binary Black Hole Coalescences

The waveform templates of the matched filtering-based gravitational-wave search ought to cover wide range of parameters for the prosperous detection. Numerical relativity (NR) has been widely accepted as the most accurate method for modeling the waveforms. Still, it is well-known that NR typically requires a tremendous amount of computational costs. In this paper, we demonstrate a proof-of-concept of a novel deterministic deep learning (DL) architecture that can generate gravitational waveforms from the merger and ringdown phases of the non-spinning binary black hole coalescence. Our model takes ${\cal O}$(1) seconds for generating approximately $1500$ waveforms with a 99.9\% match on average to one of the state-of-the-art waveform approximants, the effective-one-body. We also perform matched filtering with the DL-waveforms and find that the waveforms can recover the event time of the injected gravitational-wave signals.Comment: 11 pages, 9 figures, accepted by PR

Growth of young HIV-infected and HIV-exposed children in western Kenya: A retrospective chart review

Introduction The objective of this study was to determine the growth patterns, rates of malnutrition, and factors associated with malnutrition in children born to HIV-infected mothers in western Kenya using data from an electronic medical record system. Methods This study was a retrospective chart review of HIV-infected (HIV+) and–exposed (HEU) children (<5 years) using data collected prospectively in the course of routine clinical care and stored in the electronic medical record system in western Kenya between January 2011 and August 2016. Demographics and anthropometrics were described, with Chi-square testing to compare proportions. Multiple variable logistic regression analysis was used to identify correlates of children being stunted, underweight, and wasted. We also examined growth curves, using a resampling method to compare the areas under the fitted growth curves to compare males/females and HIV+/HEU. Results Data from 15,428 children were analyzed. The children were 51.6% (n = 7,955) female, 5.2% (n = 809) orphans, 83.3% (n = 12,851) were HEU, and 16.7% (n = 2,577) were HIV+. For HIV+ children assessed at 24 months, 50.9% (n = 217) were stunted, 26.5% (n = 145) were underweight, and 13.6% (n = 58) were wasted, while 45.0% (n = 577) of HEU children were stunted, 14.8% (n = 255) were underweight, and 5.1% (n = 65) were wasted. When comparing mean z-scores, HIV+ children tended to have larger and earlier dips in z-scores compared to HIV-exposed children, with significant differences found between the two groups (p<0.001). Factors associated with an increased risk of malnutrition included being male, HIV+, and attending an urban clinic. Maternal antiretroviral treatment during pregnancy and mixed feeding at 3 months of age decreased the risk of malnutrition. Conclusions HIV+ and HEU children differ in their anthropometrics, with HIV+ children having overall lower z-scores. Continued efforts to develop and implement sustainable and effective interventions for malnutrition are needed for children born to HIV+ mothers