Containerless low gravity processing of glass forming and immiscible alloys

Under normal one-g conditions immiscible alloys segregate extensively during solidification due to sedimentation of the more dense of the immiscible liquid phases. Immiscible (hypermonotectic) gold-rhodium alloys were processed in the 100 meter drop tube under low gravity, containerless conditions to determine the feasibility of producing dispersed structures. Three alloy compositions were utilized. Alloys containing 10 percent by volume of the gold-rich hypermonotectic phase exhibited a tendency for the gold-rich liquid to wet the outer surface of the samples. This wetting tendency led to extensive segregation in several cases. Alloys containing 80 and 90 percent by volume of the gold-rich phase possessed completely different microstructures from the 10 percent samples when processed under low-g, containerless conditions. Several samples exhibited microstructures consisting of well dispersed 2 to 3 microns diameter rhodium-rich spheres in a gold-rich matrix

Combining observations from multiple platforms across the Kuroshio northeast of Luzon : a highlight on PIES data

Author Posting. © American Meteorological Society, 2016. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 33 (2016): 2185-2203, doi:10.1175/JTECH-D-16-0095.1.This study presents amended procedures to process and map data collected by pressure-sensor-equipped inverted echo sounders (PIESs) in western boundary current regions. The modifications to the existing methodology, applied to observations of the Kuroshio from a PIES array deployed northeast of Luzon, Philippines, consist of substituting a hydrography-based mean travel time field for the PIES-based mean field and using two distinct gravest empirical mode (GEM) lookup tables across the front that separate water masses of South China Sea and North Pacific origin. In addition, this study presents a method to use time-mean velocities from acoustic Doppler current profilers (ADCPs) to reference (or “level”) the PIES-recorded pressures in order to obtain time series of absolute geostrophic velocity. Results derived from the PIES observations processed with the hydrography-based mean field and two GEMs are compared with hydrographic profiles sampled by Seagliders during the PIES observation period and with current velocity measured concurrently by a collocated ADCP array. The updated processing scheme leads to a 41% error decrease in the determination of the thermocline depth across the current, a 22% error decrease in baroclinic current velocity shear, and a 61% error decrease in baroclinic volume transports. The absolute volume transport time series derived from the leveled PIES array compares well with that obtained directly from the ADCPs with a root-mean-square difference of 3.0 Sv (1 Sv ≡ 106 m3 s–1), which is mainly attributed to the influence of ageostrophic processes on the ADCP-measured velocities that cannot be calculated from the PIES observations.The authors are supported by the Office of Naval Research (ONR) Departmental Research Initiative entitled Origins of the Kuroshio and Mindanao Currents (ONR Grant N00014-10-1-0397). MA was supported by ONR Grants N00014-15-12593 and N00014-16-1-2668. CL was supported by ONR Grant N00014-10-0308. SJ was supported by MOST Grants NSC 101-2611-M-002-018-MY3, MOST 103-2611-M-002-011, and MOST 105-2119-M-002-042.2017-04-0

Defects in coding joint formation in vivo in developing ATM-deficient B and T lymphocytes

Ataxia-telangiectasia mutated (ATM)–deficient lymphocytes exhibit defects in coding joint formation during V(D)J recombination in vitro. Similar defects in vivo should affect both T and B cell development, yet the lymphoid phenotypes of ATM deficiency are more pronounced in the T cell compartment. In this regard, ATM-deficient mice exhibit a preferential T lymphopenia and have an increased incidence of nontransformed and transformed T cells with T cell receptor α/δ locus translocations. We demonstrate that there is an increase in the accumulation of unrepaired coding ends during different steps of antigen receptor gene assembly at both the immunoglobulin and T cell receptor loci in developing ATM-deficient B and T lymphocytes. Furthermore, we show that the frequency of ATM-deficient αβ T cells with translocations involving the T cell receptor α/δ locus is directly related to the number of T cell receptor α rearrangements that these cells can make during development. Collectively, these findings demonstrate that ATM deficiency leads to broad defects in coding joint formation in developing B and T lymphocytes in vivo, and they provide a potential molecular explanation as to why the developmental impact of these defects could be more pronounced in the T cell compartment

Downstream evolution of the Kuroshio's time-varying transport and velocity structure

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 3519–3542, doi:10.1002/2016JC012519.Observations from two companion field programs—Origins of the Kuroshio and Mindanao Current (OKMC) and Observations of Kuroshio Transport Variability (OKTV)—are used here to examine the Kuroshio's temporal and spatial evolution. Kuroshio strength and velocity structure were measured between June 2012 and November 2014 with pressure-sensor equipped inverted echo sounders (PIESs) and upward-looking acoustic Doppler current profilers (ADCPs) deployed across the current northeast of Luzon, Philippines, and east of Taiwan with an 8 month overlap in the two arrays' deployment periods. The time-mean net (i.e., integrated from the surface to the bottom) absolute transport increases downstream from 7.3 Sv (±4.4 Sv standard error) northeast of Luzon to 13.7 Sv (±3.6 Sv) east of Taiwan. The observed downstream increase is consistent with the return flow predicted by the simple Sverdrup relation and the mean wind stress curl field over the North Pacific (despite the complicated bathymetry and gaps along the North Pacific western boundary). Northeast of Luzon, the Kuroshio—bounded by the 0 m s−1 isotach—is shallower than 750 dbar, while east of Taiwan areas of positive flow reach to the seafloor (3000 m). Both arrays indicate a deep counterflow beneath the poleward-flowing Kuroshio (–10.3 ± 2.3 Sv by Luzon and −12.5 ± 1.2 Sv east of Taiwan). Time-varying transports and velocities indicate the strong influence at both sections of westward propagating eddies from the ocean interior. Topography associated with the ridges east of Taiwan also influences the mean and time-varying velocity structure there.Office of Naval Research (ONR) Grant Numbers: N00014-15-12593 , N00014-16-13069; Taiwan's Ministry of Science and Technology Grant Numbers: NSC 101-2611-M-002-018-MY3 , MOST 103-2611-M-002-011 , MOST 105-2119-M-002-042; ONR Grant Numbers: N00014-10-1-0308 , N00015-10-1-04692017-11-0

Population dynamics of rhesus macaques and associated foamy virus in Bangladesh.

Foamy viruses are complex retroviruses that have been shown to be transmitted from nonhuman primates to humans. In Bangladesh, infection with simian foamy virus (SFV) is ubiquitous among rhesus macaques, which come into contact with humans in diverse locations and contexts throughout the country. We analyzed microsatellite DNA from 126 macaques at six sites in Bangladesh in order to characterize geographic patterns of macaque population structure. We also included in this study 38 macaques owned by nomadic people who train them to perform for audiences. PCR was used to analyze a portion of the proviral gag gene from all SFV-positive macaques, and multiple clones were sequenced. Phylogenetic analysis was used to infer long-term patterns of viral transmission. Analyses of SFV gag gene sequences indicated that macaque populations from different areas harbor genetically distinct strains of SFV, suggesting that geographic features such as forest cover play a role in determining the dispersal of macaques and SFV. We also found evidence suggesting that humans traveling the region with performing macaques likely play a role in the translocation of macaques and SFV. Our studies found that individual animals can harbor more than one strain of SFV and that presence of more than one SFV strain is more common among older animals. Some macaques are infected with SFV that appears to be recombinant. These findings paint a more detailed picture of how geographic and sociocultural factors influence the spectrum of simian-borne retroviruses

The design and testing of a novel mechanomyogram-driven switch controlled by small eyebrow movements

<p>Abstract</p> <p>Background</p> <p>Individuals with severe physical disabilities and minimal motor behaviour may be unable to use conventional mechanical switches for access. These persons may benefit from access technologies that harness the volitional activity of muscles. In this study, we describe the design and demonstrate the performance of a binary switch controlled by mechanomyogram (MMG) signals recorded from the frontalis muscle during eyebrow movements.</p> <p>Methods</p> <p>Muscle contractions, detected in real-time with a continuous wavelet transform algorithm, were used to control a binary switch for computer access. The automatic selection of scale-specific thresholds reduced the effect of artefact, such as eye blinks and head movement, on the performance of the switch. Switch performance was estimated by cued response-tests performed by eleven participants (one with severe physical disabilities).</p> <p>Results</p> <p>The average sensitivity and specificity of the switch was 99.7 ± 0.4% and 99.9 ± 0.1%, respectively. The algorithm performance was robust against typical participant movement.</p> <p>Conclusions</p> <p>The results suggest that the frontalis muscle is a suitable site for controlling the MMG-driven switch. The high accuracies combined with the minimal requisite effort and training show that MMG is a promising binary control signal. Further investigation of the potential benefits of MMG-control for the target population is warranted.</p

Earliest Predictor of Dropout in MOOCs: A Longitudinal Study of FutureLearn courses

Whilst a high dropout rate is a well-known problem in MOOCs, few studies take a data-driven approach to understand the reasons of such a phenomenon, and to thus be in the position to recommend and design possible adaptive solutions to alleviate it. In this study, we are particularly interested in finding a novel early detection mechanism of potential dropout, and thus be able to intervene at an as early time as possible. Additionally, unlike previous studies, we explore a light-weight approach, based on as little data as possible – since different MOOCs store different data on their users – and thus strive to create a truly generalisable method. Therefore, we focus here specifically on the generally available registration date and its relation to the course start date, via a comprehensive, larger than average, longitudinal study of several runs of all MOOC courses at the University of Warwick between 2014-1017, on the less explored European FutureLearn platform. We identify specific periods where different interventions are necessary, and propose, based on statistically significant results, specific pseudo-rules for adaptive feedback

Biological Case Against Downlisting the Whooping Crane and for Improving Implementation under the Endangered Species Act

The Whooping Crane (Grus americana; WHCR) is a large, long-lived bird endemic to North America. The remnant population migrates between Aransas National Wildlife Refuge, USA, and Wood Buffalo National Park, Canada (AWBP), and has recovered from a nadir of 15-16 birds in 1941 to ~540 birds in 2022. Two ongoing reintroduction efforts in Louisiana and the Eastern Flyway together total ~150 birds. Evidence indicates the U.S. Fish and Wildlife Service (USFWS) is strongly considering downlisting the species from an endangered to a threatened status under the Endangered Species Act (ESA). We examined the current status of the WHCR through the lens of ESA threat factors, the USFWS’s Species Status Assessment (SSA) framework, and other avian downlisting actions to determine if the action is biologically warranted. Our research indicates that WHCRs are facing an intensification of most threat drivers across populations and important ranges. The AWBP is still relatively small compared to other crane species and most birds of conservation concern. To date, only one avian species has been downlisted from an endangered status with an estimated population of \u3c3,000 individuals. Representation in terms of WHCRs historic genetic, geographic, and life history variation remains limited. Also, the lack of spatial connectivity among populations, reliance of the reintroduced populations on supplementation, and continued habitat loss suggest that WHCR populations may not be resilient to large stochastic disturbances. Given that reintroduced populations are not self-sustaining, neither supplies true redundancy for the AWBP. Proposed downlisting before recovery plan population criteria have been met is objectively unwarranted 3 and reflects USFWS inconsistency across ESA actions. Only by incorporating basic quantitative criteria and added oversight into ESA listing decisions can we avoid an action as misguided as downlisting the Whooping Crane without consideration of its recovery plan criteria or ostensibly its population ecology