Preliminary results of simulated vortex encounters by a twin-engine, commercial aircraft during final landing approach

Piloted simulations of encounters with vortices of various ages and degrees of attenuation were performed with the Visual Motion Simulator. In the simulations, a twin engine, commercial transport on final approach, encountered the modeled vortices of a four engine, wide body, commercial transport. The data show the effect of vortex age and attenuation on the severity of the initial upset, as well as the effect of the vortex encounters on the landing capability

The Past, Present, and Future of Research on Interviewer Effects

Interviewer-administered surveys are a primary method of collecting information from populations across the United States and the world. Various types of interviewer-administered surveys exist, including large-scale government surveys that monitor populations (e.g., the Current Population Survey), surveys used by the academic community to understand what people think and do (e.g., the General Social Survey), and surveys designed to gauge public opinion at a particular time point (e.g., the Gallup Daily Tracking Poll). Interviewers participate in these data collection efforts in a multitude of ways, including creating lists of housing units for sampling, persuading sampled units to participate, and administering survey questions (Morton-Williams 1993). In an increasing number of surveys, interviewers are also tasked with collecting blood, saliva, and other biomeasures, and asking survey respondents for consent to link survey data to administrative records (Sakshaug 2013). Interviewers are also used in mixed mode surveys to recruit and interview non respondents after less expensive modes like mail and web have failed (e.g., the American Community Survey and the Agricultural Resource Management Survey; de Leeuw 2005; Dillman, Smyth and Christian 2014; Olson et al. 2019). In completing these varied tasks, interviewers affect survey costs and coverage, nonresponse, measurement, and processing errors (Schaeffer, Dykema and Maynard 2010; West and Blom 2017)

Science lives: School choices and ‘natural tendencies’

An analysis of 12 semi-structured interviews with university-based scientists and non-scientists illustrates their life journeys towards, or away from, science and the strengths and impact of life occurrences leading them to choose science or non-science professions. We have adopted narrative approaches and used Mezirow's transformative learning theory framework. The areas of discussion from the result have stressed on three main categories that include ‘smooth transition’, ‘incremental wavering transition' and ‘transformative transition’. The article concludes by discussing the key influences that shaped initial attitudes and direction in these people through natural inclination, environmental inspirations and perceptions of science

Human Performance Contributions to Safety in Commercial Aviation

In the commercial aviation domain, large volumes of data are collected and analyzed on the failures and errors that result in infrequent incidents and accidents, but in the absence of data on behaviors that contribute to routine successful outcomes, safety management and system design decisions are based on a small sample of non- representative safety data. Analysis of aviation accident data suggests that human error is implicated in up to 80% of accidents, which has been used to justify future visions for aviation in which the roles of human operators are greatly diminished or eliminated in the interest of creating a safer aviation system. However, failure to fully consider the human contributions to successful system performance in civil aviation represents a significant and largely unrecognized risk when making policy decisions about human roles and responsibilities. Opportunities exist to leverage the vast amount of data that has already been collected, or could be easily obtained, to increase our understanding of human contributions to things going right in commercial aviation. The principal focus of this assessment was to identify current gaps and explore methods for identifying human success data generated by the aviation system, from personnel and within the supporting infrastructure

Intermediate phase, network demixing, boson and floppy modes, and compositional trends in glass transition temperatures of binary AsxS1-x system

The structure of binary As_xS_{1-x} glasses is elucidated using modulated-DSC, Raman scattering, IR reflectance and molar volume experiments over a wide range (8%<x<41%) of compositions. We observe a reversibility window in the calorimetric experiments, which permits fixing the three elastic phases; flexible at x<22.5%, intermediate phase (IP) in the 22.5%<x<29.5% range, and stressed-rigid at x>29.5%. Raman scattering supported by first principles cluster calculations reveal existence of both pyramidal (PYR, As(S1/2)3) and quasi-tetrahedral(QT, S=As(S1/2)3) local structures. The QT unit concentrations show a global maximum in the IP, while the concentration of PYR units becomes comparable to those of QT units in the phase, suggesting that both these local structures contribute to the width of the IP. The IP centroid in the sulfides is significantly shifted to lower As content x than in corresponding selenides, a feature identified with excess chalcogen partially segregating from the backbone in the sulfides, but forming part of the backbone in selenides. These ideas are corroborated by the proportionately larger free volumes of sulfides than selenides, and the absence of chemical bond strength scaling of Tgs between As-sulfides and As-selenides. Low-frequency Raman modes increase in scattering strength linearly as As content x of glasses decreases from x = 20% to 8%, with a slope that is close to the floppy mode fraction in flexible glasses predicted by rigidity theory. These results show that floppy modes contribute to the excess vibrations observed at low frequency. In the intermediate and stressed rigid elastic phases low-frequency Raman modes persist and are identified as boson modes. Some consequences of the present findings on the optoelectronic properties of these glasses is commented upon.Comment: Accepted for PR

Staphylococcus aureus nasal colonization in HIV-seropositive and HIV-seronegative drug users

Nasal colonization plays an important role in the pathogenesis of Staphylococcus aureus infections. To identify characteristics associated with colonization, we studied a cross-section of a well-described cohort of HIV-seropositive and -seronegative active and former drug users considered at risk for staphylococcal infections. Sixty percent of the 217 subjects were Hispanic, 36% were women, 25% actively used injection drugs, 23% actively used inhalational drugs, 23% received antibiotics, and 35% were HIV-seropositive. Forty-one percent of subjects had positive nasal cultures for S. aureus. The antibiotic susceptibility patterns were similar to the local hospital's outpatient isolates and no dominant strain was identified by arbitrarily primed polymerase chain reaction (AB-PCR). Variables significantly and independently associated with colonization included antibiotic use (odds ratio [OR] = 0.37; confidence interval [CI] = 0.18-0.77), active inhalational drug use within the HIV-seropositive population (OR = 2.36; CI = 1.10-5.10) and female gender (OR = 1.97; CI = 1.09-3.57). Characteristics not independently associated included injection drug use, HIV status, and CD4 count. The association with active inhalational drug use, a novel finding, may reflect alterations in the integrity of the nasal mucosa. The lack of association between HIV infection and S. aureus colonization, which is contrary to most previous studies, could be explained by our rigorous control for confounding variables or by a limited statistical power due to the sample sizes

Clothing Longevity Protocol: final

The Clothing Longevity Protocol offers guidelines for good practice in order to aid moves towards garments that will last longer and thus to help protect brand value, screen out garments which fail prematurely and reduce the environmental impact of the clothing sector

Split Tickets? On the Strategic Allocation of Presidential Versus Vice Presidential Visits in 2016

This article analyzes the strategic allocation of presidential campaign visits in 2016. In particular, we test whether each campaign disproportionately targeted its presidential versus vice presidential candidates’ visits toward voters with whom they shared a salient demographic or political characteristic. Our purpose in doing so is to discern whether—and, if so, among which groups—the campaigns perceived the candidates as having a strategic advantage in appealing to affiliated voters. To this end, we analyze an original database of 2016 campaign visits that includes local population characteristics for each host site. Our results indicate that each ticket’s visits were highly coordinated across states, but frequently divergent within states. At the substate level, we find several systematic differences in the populations visited by presidential versus vice presidential candidates—in some cases aligning with a candidate’s personal characteristics. We discuss these findings’ implications with respect to campaign strategy and vice presidential selection

Development of Readout Interconnections for the Si-W Calorimeter of SiD

The SiD collaboration is developing a Si-W sampling electromagnetic calorimeter, with anticipated application for the International Linear Collider. Assembling the modules for such a detector will involve special bonding technologies for the interconnections, especially for attaching a silicon detector wafer to a flex cable readout bus. We review the interconnect technologies involved, including oxidation removal processes, pad surface preparation, solder ball selection and placement, and bond quality assurance. Our results show that solder ball bonding is a promising technique for the Si-W ECAL, and unresolved issues are being addressed.Comment: 8 pages + title, 6 figure