Application of multidisciplinary optimization methods to the design of a supersonic transport

An optimization design method is discussed. This method is based on integrating existing disciplinary analysis and sensitivity analysis techniques by means of generalized sensitivity equations. A generic design system implementing this method is described. The system is being used to design the configuration and internal structure of a supersonic transport wing for optimum performance. This problem combines the disciplines of linear aerodynamics, structures, and performance. Initial results which include the disciplines of aerodynamics and structures in a conventional minimum weight design under static aeroelastic constraints are presented

Quality of Tax Services, Moderated by Trust in State Internal Revenue Service and Voluntary Tax Compliance Behaviour among Individual Taxpayers in South-West, Nigeria

Research on tax compliance is of economic, social and political benefit to the government and the citizens. Constant loss of tax revenue due to level of Quality of Tax Service (QTS) rendered by tax authority is perceived to have adversely affected nation’s revenue generation and infrastructural development. Researches have been carried out on taxpayers’ compliance, but not many considered the effect of QTS in their study. This studied looked at the probable influence of QTS on taxpayers’ Voluntary Tax Compliance (VTC) behaviour in South-West, Nigeria. The study used survey research design with study population of 5,216,422 individual taxpayers. Data were collected with validated questionnaire by means of random sampling techniques. Sample size of 1,200 was used with a response rate of 87.6%. Descriptive and inferential statistics were used to analyse data at 5% significance level. The study revealed that QTS positively influenced VTC among individual taxpayers in the study states (Adj.R2 =.117, F(6, 1050) =24.139, p =.000). There was evidence that trust in State Internal Revenue Service, QTS and employment status have significant relationship with VTC behaviour while gender, age and educational level do not have significant relationship with VTC in the study states respectively. The study concluded that QTS influenced VTC. Therefore, lack of tax awareness, tax education/information and poor tax service delivery was responsible for tax non-compliance. The study recommended that government should carry out tax education/information and tax awareness to taxpayers while tax officials should apply the concept of public management to tax service delivery

Analysis of Beam Deflection Measurements in the Presence of Linear Absorption

We develop a series of analytical approximations allowing for rapid extraction of the nonlinear parameters from beam deflection measurements. We then apply these approximations to the analysis of cadmium silicon phosphide and compare the results against previously published parameter extraction methods and find good agreement for typical experimental conditions

Ready for Fall? Near-Term Effects of Voluntary Summer Learning Programs on Low-Income Students' Learning Opportunities and Outcomes

This report is the second of five volumes from a five-year study, funded by The Wallace Foundation and conducted by the RAND Corporation, designed as a randomized controlled trial that assesses student outcomes in three waves: in the fall after the 2013 summer program (reported here), at the end of the school year following the program, and after a second summer program in 2014 (to show the cumulative effects of two summer programs). The goal of the study is to answer one key question: Do voluntary, district-run summer programs that include academics and enrichment activities improve student academic achievement and other outcomes, such as social and emotional competence

Learning From Summer: Effects of Voluntary Summer Learning Programs on Low-Income Urban Youth

The largest-ever study of summer learning finds that students with high attendance in free, five to six-week, voluntary summer learning programs experienced educationally meaningful benefits in math and reading.The findings are important because children from low-income families lose ground in learning over the summer compared to their more affluent peers. Voluntary, district-run summer programs could help shrink this gap and have the potential to reach more students than traditional summer school or smaller-scale programs run by outside organizations. Yet until now little has been known about the impact of these programs and how they can succeed. Wallace's $50 million National Summer Learning Project seeks to help provide answers.Since 2011, five urban school districts and their partners, the RAND Corporation and Wallace have been working together to find out whether and how voluntary-attendance summer learning programs combining academics and enrichment can help students succeed in school.Starting in 2013, RAND conducted a randomized controlled trial (RCT) in five districts—Boston; Dallas; Duval County, Florida; Pittsburgh; and Rochester—to evaluate educational outcomes, focusing on children who were in 3rd grade in spring of that year. The 5,600 students who applied to summer programs were randomly assigned to one of two groups—those selected to take part in the programs for two summers (the treatment group) and those not selected (the control group). The study analyzed outcomes for 3,192 students offered access to the programs.Researchers found that those who attended a five-to-six-week summer program for 20 or more days in 2013 did better on state math tests than similar students in the control group. This advantage was statistically significant and lasted through the following school year. The results are even more striking for high attenders in 2014: They outperformed control group students in both math and English Language Arts (ELA), on fall tests and later, in the spring. The advantage after the second summer was equivalent to 20-25 percent of a year's learning in math and ELA.These findings are correlational but controlled for prior achievement and demographics, giving researchers confidence that the benefits are likely due to the programs and meeting the requirements for promising evidence under the Every Student Succeeds Act.High-attending students were also rated by teachers as having stronger social and emotional competencies than the control group students; however, researchers have less confidence that this was due to the programs, given the lack of prior data on these competencies.About 60 percent of students attending at least one day met the 20-day threshold that was defined as high attendance.Separately, the study also examined the impact of the programs on all students who were offered access, whether or not they actually attended. Because many students did not attend at a high level, and some didn't attend at all, the average benefits for all of these students were smaller and not statistically significant, with the exception of a modest but educationally meaningful boost in math scores in the fall after the first summer equivalent to 15 percent of a year's learning. These findings are causal, meaning that researchers are confident that they were due to the programs, and meet the standard of strong evidence under the Every Student Succeeds Act.For students to experience lasting benefits from attending summer programs, the report recommends that districts: run programs for at least five weeks; promote high attendance; include sufficient instructional time and protect it; invest in instructional quality; and factor in attendance and likely no-show rates when staffing the programs in order to lower per-student costs

The occupancy-abundance relationship and sampling designs using occupancy to monitor populations of Asian bears

Designing a population monitoring program for Asian bears presents challenges associated with their low densities and detectability, generally large home ranges, and logistical or resource constraints. The use of an occupancy-based method to monitor bear populations can be appropriate under certain conditions given the mechanistic relationship between occupancy and abundance. The form of the occupancy\u2013abundance relationship is dependent on species-specific characteristics such as home range size and population density, as well as study area size. To assess the statistical power of tests to detect population change of Asian bears, we conducted a study using a range of scenarios by simulating spatially explicit individual-based capture-recapture data from a demographically open model. Simulations assessed the power to detect changes in population density via changes in site-level occupancy or abundance through time, estimated using a standard occupancy model or a Royle-Nichols model, both with point detectors (representing camera traps). We used IUCN Red List criteria as a guide in selection of two population decline scenarios (20% and 50%), but we chose a shorter time horizon (10 years = 1 bear generation), meaning that declines were steeper than used for IUCN criteria (3 generations). Our simulations detected population declines of 50% with high power (>0.80) and low false positive rates (FPR: incorrectly detecting a decline) (<0.10) when detectors were spaced at > 0.67 times the home range diameter (home-range spacing ratio: HRSR, a measure of spatial correlation), such that bears would tend to overlap no more than two detectors. There was high (0.85) correlation between realized occupancy and N in these scenarios. The FPR increased as the HRSR decreased because of spatial correlation in the occupancy process induced when individual home ranges overlap multiple detectors. The mean statistical power to detect more gradual population declines (20% in 10 years) with HRSR > 0.67 was low for occupancy models 0.22 (maximum power 0.67) and Royle-Nichols models (0.24; maximum power 0.67), suggesting that declines of this magnitude may not be described reliably with 10 years of monitoring. Our results demonstrated that under many realistic scenarios that we explored, false positive rates were unacceptably high. We highlight that when designing occupancy studies, the spacing between point detectors be at least 0.67 times the diameter of the home range size of the larger sex (e.g., males) when the assumptions of the spatial capture-recapture model used for simulation are met

Increased complications of COVID-19 in people with cardiovascular disease: Role of the renin-angiotensin-aldosterone system (RAAS) dysregulation

The rapid spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID?19), has had a dramatic negative impact on public health and economies worldwide. Recent studies on COVID-19 complications and mortality rates suggest that there is a higher prevalence in cardiovascular diseases (CVD) patients. Past investigations on the associations between pre-existing CVDs and susceptibility to coronavirus infections including SARS-CoV and the Middle East Respiratory Syndrome coronavirus (MERS-CoV), have demonstrated similar results. However, the underlying mechanisms are poorly understood. This has impeded adequate risk stratification and treatment strategies for CVD patients with SARS-CoV-2 infections. Generally, dysregulation of the expression of angiotensin?converting enzyme (ACE) and the counter regulator, angiotensin?converting enzyme 2 (ACE2) is a hallmark of cardiovascular risk and CVD. ACE2 is the main host receptor for SARS-CoV-2. Although further studies are required, dysfunction of ACE2 after virus binding and dysregulation of the renin-angiotensin-aldosterone system (RAAS) signaling may worsen the outcomes of people affected by COVID-19 and with preexisting CVD. Here, we review the current knowledge and outline the gaps related to the relationship between CVD and COVID-19 with a focus on the RAAS. Improved understanding of the mechanisms regulating viral entry and the role of RAAS may direct future research with the potential to improve the prevention and management of COVID-19.Scopu

Photolysis of a caged peptide reveals rapid action of NSF prior to neurotransmitter release

Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 105 (2008): 347-352, doi:10.1073/pnas.0707197105.The time at which the N-ethylmaleimide-sensitive factor (NSF) acts during synaptic vesicle trafficking was identified by time-controlled perturbation of NSF function with a photo-activatable inhibitory peptide. Photolysis of this caged peptide in the squid giant presynaptic terminal caused an abrupt (0.2 s) slowing of the kinetics of the postsynaptic current (PSC) and a more gradual (2-3 s) reduction in PSC amplitude. Based on the rapid rate of these inhibitory effects relative to the speed of synaptic vesicle recycling, we conclude that NSF functions in reactions that immediately precede neurotransmitter release. Our results indicate the locus of SNARE protein recycling in presynaptic terminals and reveal a new target for rapid regulation of transmitter release.T.K. was supported by a Grass Fellowship in Neuroscience, an HFSP long-term fellowship and the Feodor-Lynen Program of the Alexander von Humboldt Foundation. Y.L. received a American Heart Association predoctoral fellowship. The research also was supported by NIH NS-21624