320 research outputs found
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Digital Systems Teaching and Research (DSTR) Robot: A Flexible Platform for Education and Applied Research
The DSTR (pronounced āDisasterā) robot has a strong history of being adaptable to different userās needs, and there are many opportunities ahead that indicate that the sky, quite literally, is not the limit for this robust platform. This paper provides a historical perspective on the development of the DSTR robot as a collaborative design developed by the Mobile Integrated Solutions Laboratory (MISL) at Texas A&M University and ASEP 4X4 Inc. Texas Instruments has been a major partner in the integration of the control electronics, and Texas Space Technology Applications and Research (T STAR) LLC has played a significant role in the propagation of the DSTR robot as an adaptable applied research/education/STEM outreach platform. The paper will present examples of the strong industry-academic relationships that allow the DSTR robot to be utilized in a multitude of experiential learning environments. In addition to a number of STEM outreach activities, the DSTR robots are being used in the Introduction to Engineering course at Blinn College and in the Freshman Engineering curriculum at Texas A&M University. DSTRs have also been selected by NASA scientists as a low-cost lunar sample collector. The paper will also discuss the newly developed DSTR-E (DSTR Engineering) unit which requires students to perform several engineering tasks during the build process. The paper will also include the lessons learned from initial design through its transfer to the private sector for commercialization and future plans.Cockrell School of Engineerin
Impact of blood group on survival following critical illness: a single-centre retrospective observational study
Background Predicting patient outcomes following critical illness is challenging. Recent evidence has suggested that patients with blood group AB are more likely to survive following major cardiac surgery, and this is associated with a reduced number of blood transfusions. However, there are no current data to indicate whether a patientās blood group affects general intensive care outcomes.
Objective The objective of this study was to determine if ABO blood group affects survival in intensive care. The primary outcome measure was 90-day mortality with a secondary outcome measure of the percentage of patients receiving a blood transfusion.
Design Retrospective analysis of electronically collected intensive care data, blood group and transfusion data.
Setting General intensive care unit (ICU) of a major tertiary hospital with both medical and surgical patients.
Patients All patients admitted to ICU between 2006 and 2016 who had blood group data available.
Intervention None.
Measurements and main results 7340 patients were included in the study, blood group AB accounted for 3% (221), A 41% (3008), B 10.6% (775) and O 45.4% (3336). These values are similar to UK averages. Baseline characteristics between the groups were similar. Blood group AB had the greatest survival benefit (blood group AB 90-day survival estimate 76.75, 95% CI 72.89 to 80.61 with the overall estimate 72.07, 95% CI 71.31 to 72.82) (log-rank Ļ2 16.128, p=0.001). Transfusion requirements were similar in all groups with no significant difference between the percentages of patients transfused (AB 23.1%, A 21.5%, B 18.7%, O 19.9%, Pearson Ļ2 5.060 p=0.167).
Conclusion Although this is primarily a hypothesis generating study, intensive care patients with blood group AB appeared to have a higher 90-day survival compared with other blood groups. There was no correlation between blood group and percentage of patients receiving transfusion
Pathogen-specific immune fingerprints during acute infection: The diagnostic potential of human Ī³Ī“ T-cells
Zoledronate rescues immunosuppressed monocytes in sepsis patients
Severe sepsis is often accompanied by a transient immune paralysis, which is associated with enhanced susceptibility to secondary infections and poor clinical outcomes. The functional impairment of antigenāpresenting cells is considered to be a major hallmark of this septic immunosuppression, with reduced HLAāDR expression on circulating monocytes serving as predictor of mortality. Unconventional lymphocytes like Ī³Ī“ T cells have the potential to restore immune defects in a variety of pathologies including cancer but their use to rescue sepsisāinduced immunosuppression has not been investigated. Our own previous work showed that VĪ³9/VĪ“2+ Ī³Ī“ T cells are potent activators of monocytes from healthy volunteers in vitro, and in individuals with osteoporosis after firstātime administration of the antiābone resorption drug zoledronate in vivo. We show here that zoledronate readily induces upregulation of HLAāDR, CD40 and CD64 on monocytes from both healthy controls and sepsis patients, which could be abrogated by neutralising the proāinflammatory cytokines IFNāĪ³ and TNFāĪ± in the cultures. In healthy controls, the upregulation of HLAāDR on monocytes was proportional to the baseline percentage of VĪ³9/VĪ“2 T cells in the PBMC population. Of note, a proportion of sepsis patients studied here did not show a demonstrable response to zoledronate, predominantly patients with microbiologically confirmed bloodstream infections, compared to sepsis patients with more localised infections marked by negative blood cultures. Taken together, our results suggest that zoledronate can, at least in some individuals, rescue immunosuppressed monocytes during acute sepsis and thus may help improve clinical outcomes during severe infection
GeoWaVe: Geometric median clustering with weighted voting for ensemble clustering of cytometry data
Motivation
Clustering is an unsupervised method for identifying structure in unlabelled data. In the context of cytometry, it is typically used to categorise cells into subpopulations of similar phenotypes. However, clustering is greatly dependent on hyperparameters and the data to which it is applied as each algorithm makes different assumptions and generates a different āviewā of the dataset. As such, the choice of clustering algorithm can significantly influence results, and there is often not one preferred method but different insights to be obtained from different methods. To overcome these limitations, consensus approaches are needed that directly address the effect of competing algorithms. To the best of our knowledge, consensus clustering algorithms designed specifically for the analysis of cytometry data are lacking.
Results
We present a novel ensemble clustering methodology based on geometric median clustering with weighted voting (GeoWaVe). Compared to graph ensemble clustering methods that have gained popularity in scRNA-seq analysis, GeoWaVe performed favourably on different sets of high-dimensional mass and flow cytometry data. Our findings provide proof of concept for the power of consensus methods to make the analysis, visualisation and interpretation of cytometry data more robust and reproducible. The wide availability of ensemble clustering methods is likely to have a profound impact on our understanding of cellular responses, clinical conditions, and therapeutic and diagnostic options
Value-based decision-making of cigarette and nondrug rewards in dependent and occasional cigarette smokers:An FMRI study
Little is known about the neural functioning that underpins drug valuation and choice in addiction, including nicotine dependence. Following ad libitum smoking, 19 dependent smokers (smokedā„10/day) and 19 occasional smokers (smoked 0.5ā5/week) completed a decisionāmaking task. First, participants stated how much they were willingātoāpay for various amounts of cigarettes and shop vouchers. Second, during functional magnetic resonance imaging, participants decided if they wanted to buy these cigarettes and vouchers for a set amount of money. We examined decisionāmaking behaviour and brain activity when faced with cigarette and voucher decisions, purchasing (vs not purchasing) cigarettes and vouchers, and āvalue signalsā where brain activity correlated with cigarette and voucher value. Dependent smokers had a higher willingnessātoāpay for cigarettes and greater activity in the bilateral middle temporal gyrus when faced with cigarette decisions than occasional smokers. Across both groups, the decision to buy cigarettes was associated with activity in the left paracingulate gyrus, right nucleus accumbens, and left amygdala. The decision to buy vouchers was associated with activity in the left superior frontal gyrus, but dependent smokers showed weaker activity in the left posterior cingulate gyrus than occasional smokers. Across both groups, cigarette value signals were observed in the left striatum and ventromedial prefrontal cortex. To summarise, nicotine dependence was associated with greater behavioural valuation of cigarettes and brain activity during cigarette decisions. When purchasing cigarettes and vouchers, reward and decisionārelated brain regions were activated in both groups. For the first time, we identified value signals for cigarettes in the brain
Local and global Fokker-Planck neoclassical calculations showing flow and bootstrap current modification in a pedestal
In transport barriers, particularly H-mode edge pedestals, radial scale
lengths can become comparable to the ion orbit width, causing neoclassical
physics to become radially nonlocal. In this work, the resulting changes to
neoclassical flow and current are examined both analytically and numerically.
Steep density gradients are considered, with scale lengths comparable to the
poloidal ion gyroradius, together with strong radial electric fields sufficient
to electrostatically confine the ions. Attention is restricted to relatively
weak ion temperature gradients (but permitting arbitrary electron temperature
gradients), since in this limit a delta-f (small departures from a Maxwellian
distribution) rather than full-f approach is justified. This assumption is in
fact consistent with measured inter-ELM H-Mode edge pedestal density and ion
temperature profiles in many present experiments, and is expected to be
increasingly valid in future lower collisionality experiments. In the numerical
analysis, the distribution function and Rosenbluth potentials are solved for
simultaneously, allowing use of the exact field term in the linearized
Fokker-Planck collision operator. In the pedestal, the parallel and poloidal
flows are found to deviate strongly from the best available conventional
neoclassical prediction, with large poloidal variation of a different form than
in the local theory. These predicted effects may be observable experimentally.
In the local limit, the Sauter bootstrap current formulae appear accurate at
low collisionality, but they can overestimate the bootstrap current near the
plateau regime. In the pedestal ordering, ion contributions to the bootstrap
and Pfirsch-Schluter currents are also modified
The Effects of Close Companions (and Rotation) on the Magnetic Activity of M Dwarfs
We present a study of close white dwarf and M dwarf (WD+dM) binary systems
and examine the effect that a close companion has on the magnetic field
generation in M dwarfs. We use a base sample of 1602 white dwarf -- main
sequence binaries from Rebassa et al. to develop a set of color cuts in GALEX,
SDSS, UKIDSS, and 2MASS color space to construct a sample of 1756 WD+dM
high-quality pairs from the SDSS DR8 spectroscopic database. We separate the
individual WD and dM from each spectrum using an iterative technique that
compares the WD and dM components to best-fit templates. Using the absolute
height above the Galactic plane as a proxy for age, and the H{\alpha} emission
line as an indicator for magnetic activity, we investigate the age-activity
relation for our sample for spectral types \leqM7. Our results show that
early-type M dwarfs (\leqM4) in close binary systems are more likely to be
active and have longer activity lifetimes compared to their field counterparts.
However, at a spectral type of M5 (just past the onset of full convection in M
dwarfs), the activity fraction and lifetimes of WD+dM binary systems becomes
more comparable to that of the field M dwarfs. One of the implications of
having a close binary companion is presumed to be increased stellar rotation
through disk-disruption, tidal effects, or angular momentum exchange. Thus, we
interpret the similarity in activity behavior between late-type dMs in WD+dM
pairs and late-type field dMs to be due to a decrease in sensitivity in close
binary companions (or stellar rotation), which has implications for the nature
of magnetic activity in fully-convective stars. (Abridged)Comment: 21 pages, 19 figures, emulateapj style, accepted to Astronomical
Journal June 28, 201
Evidence of seismic slip on a large splay fault in the Hikurangi subduction zone
The Hikurangi subduction zone is capable of producing moderate to large earthquakes as well as regularly repeating slow slip events. However, it is unclear what structures host these different slip styles along the margin. Here we address whether splay faults can host seismic slip at shallow (1 m as observed in the 1947 Poverty and Tolaga Bay earthquakes
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