1,120 research outputs found
Examining Equity in Tenure Processes at Higher Education Music Programs: An Institutional Ethnography
As part of a larger mixed-methods study, this article presents findings from research on processes of tenure in Canadian higher education music faculties. The Principle Investigator and three teams of two researchers analyzed the process of tenure at three Canadian institutions to gain insight into how tenure decisions are made in relation to gender and race/ethnicity. The researchers used institutional ethnography, developed by sociologist Dorothy Smith, to examine institutional documents that organize tenure, as well as how documents organize peopleâs actions, studied through interviews with key stakeholders, such as directors, tenure applicants, and union representatives. The findings from the three sites were analyzed and integrated into one composite institution, and the researchers created a written analysis as well as a conceptual map of the process. The researchers found that the existence of a collective agreement created greater transparency in the tenure process for all stakeholders, contributing to a somewhat smoother path to tenure. However, ambiguities remained that created anxiety and stress, such as the âmoving barâ related to publications and quantity vs. quality concerns, and the uncertainty about how artistic or musical achievements might âcountâ in the tenure dossier. The mantra of âhire the best candidatesâ appears to disadvantage women and people of colour, who continue to be hired into tenure-track positions at much lower rates than men and White candidates. Policies to encourage diversity in hiring appear to be weak and poorly monitored
An Experimental Field Study of Delayed Density Dependence in Natural Populations of Aedes albopictus
Aedes albopictus, a species known to transmit dengue and chikungunya viruses, is primarily a container-inhabiting mosquito. The potential for pathogen transmission by Ae. albopictus has increased our need to understand its ecology and population dynamics. Two parameters that we know little about are the impact of direct density-dependence and delayed density-dependence in the larval stage. The present study uses a manipulative experimental design, under field conditions, to understand the impact of delayed density dependence in a natural population of Ae. albopictus in Raleigh, North Carolina. Twenty liter buckets, divided in half prior to experimentation, placed in the field accumulated rainwater and detritus, providing oviposition and larval production sites for natural populations of Ae. albopictus. Two treatments, a larvae present and larvae absent treatment, were produced in each bucket. After five weeks all larvae were removed from both treatments and the buckets were covered with fine mesh cloth. Equal numbers of first instars were added to both treatments in every bucket. Pupae were collected daily and adults were frozen as they emerged. We found a significant impact of delayed density-dependence on larval survival, development time and adult body size in containers with high larval densities. Our results indicate that delayed density-dependence will have negative impacts on the mosquito population when larval densities are high enough to deplete accessible nutrients faster than the rate of natural food accumulation
How to Choose a Champion
League competition is investigated using random processes and scaling
techniques. In our model, a weak team can upset a strong team with a fixed
probability. Teams play an equal number of head-to-head matches and the team
with the largest number of wins is declared to be the champion. The total
number of games needed for the best team to win the championship with high
certainty, T, grows as the cube of the number of teams, N, i.e., T ~ N^3. This
number can be substantially reduced using preliminary rounds where teams play a
small number of games and subsequently, only the top teams advance to the next
round. When there are k rounds, the total number of games needed for the best
team to emerge as champion, T_k, scales as follows, T_k ~N^(\gamma_k) with
gamma_k=1/[1-(2/3)^(k+1)]. For example, gamma_k=9/5,27/19,81/65 for k=1,2,3.
These results suggest an algorithm for how to infer the best team using a
schedule that is linear in N. We conclude that league format is an ineffective
method of determining the best team, and that sequential elimination from the
bottom up is fair and efficient.Comment: 6 pages, 3 figure
Autonomic modulation in patients with heart failure increases beat-to-beat variability of ventricular action potential duration
Background: Exaggerated beat-to-beat variability of ventricular action potential duration (APD) is linked to arrhythmogenesis. Sympathetic stimulation has been shown to increase QT interval variability, but its effect on ventricular APD in humans has not been determined.Methods and Results: Eleven heart failure patients with implanted bi-ventricular pacing devices had activationârecovery intervals (ARI, surrogate for APD) recorded from LV epicardial electrodes under constant RV pacing. Sympathetic activity was increased using a standard autonomic challenge (Valsalva) and baroreceptor indices were applied to determine changes in sympathetic stimulation. Two Valsalvas were performed for each study and were repeated, both off and on bisoprolol. In addition sympathetic nerve activity (SNA) was measured from skin electrodes on the thorax using a novel validated method. Autonomic modulation significantly increased mean short-term variability in ARI; off bisoprolol mean STV increased from 3.73 ± 1.3 to 5.27 ± 1.04 ms (p = 0.01), on bisoprolol mean STV of ARI increased from 4.15 ± 1.14 to 4.62 ± 1 ms (p = 0.14). Adrenergic indices of the Valsalva demonstrated significantly reduced beta-adrenergic function when on bisoprolol (Î pressure recovery time, p = 0.04; Î systolic overshoot in Phase IV, p = 0.05). Corresponding increases in SNA from rest both off (1.4 uV, p < 0.01) and on (0.7 uV, p < 0.01) bisoprolol were also seen.Conclusions: Beat-to-beat variability of ventricular APD increases during brief periods of increased sympathetic activity in patients with heart failure. Bisoprolol reduces, but does not eliminate, these effects. This may be important in the genesis of ventricular arrhythmias in heart failure patients
Interpretable Deep Models for Cardiac Resynchronisation Therapy Response Prediction
Advances in deep learning (DL) have resulted in impressive accuracy in some
medical image classification tasks, but often deep models lack
interpretability. The ability of these models to explain their decisions is
important for fostering clinical trust and facilitating clinical translation.
Furthermore, for many problems in medicine there is a wealth of existing
clinical knowledge to draw upon, which may be useful in generating
explanations, but it is not obvious how this knowledge can be encoded into DL
models - most models are learnt either from scratch or using transfer learning
from a different domain. In this paper we address both of these issues. We
propose a novel DL framework for image-based classification based on a
variational autoencoder (VAE). The framework allows prediction of the output of
interest from the latent space of the autoencoder, as well as visualisation (in
the image domain) of the effects of crossing the decision boundary, thus
enhancing the interpretability of the classifier. Our key contribution is that
the VAE disentangles the latent space based on `explanations' drawn from
existing clinical knowledge. The framework can predict outputs as well as
explanations for these outputs, and also raises the possibility of discovering
new biomarkers that are separate (or disentangled) from the existing knowledge.
We demonstrate our framework on the problem of predicting response of patients
with cardiomyopathy to cardiac resynchronization therapy (CRT) from cine
cardiac magnetic resonance images. The sensitivity and specificity of the
proposed model on the task of CRT response prediction are 88.43% and 84.39%
respectively, and we showcase the potential of our model in enhancing
understanding of the factors contributing to CRT response.Comment: MICCAI 2020 conferenc
Rectal Optical Markers for In-vivo Risk Stratification of Premalignant Colorectal Lesions.
Purpose: Colorectal cancer remains the second leading cause of cancer deaths in the U.S. despite being eminently preventable by colonoscopy via removal of premalignant adenomas. In order to more effectively reduce colorectal cancer mortality, improved screening paradigms are needed. Our group pioneered the use of low coherence enhanced backscattering (LEBS) spectroscopy to detect the presence of adenomas throughout the colon via optical interrogation of the rectal mucosa. In a previous ex-vivo biopsy study of 219 patients, LEBS demonstrated excellent diagnostic potential with 89.5% accuracy for advanced adenomas. The objective of the current cross-sectional study is to assess the viability of rectal LEBS in-vivo. Experimental Design: Measurements from 619 patients were taken using a minimally invasive 3.4 mm diameter LEBS probe introduced into the rectum via anoscope or direct insertion, requiring ~1 minute from probe insertion to withdrawal. The diagnostic LEBS marker was formed as a logistic regression of the optical reduced scattering coefficient ÎŒsâ and mass density distribution factor D. Results: The rectal LEBS marker was significantly altered in patients harboring advanced adenomas and multiple non-advanced adenomas throughout the colon. Blinded and cross-validated test performance characteristics showed 88% sensitivity to advanced adenomas, 71% sensitivity to multiple non-advanced adenomas, and 72% specificity in the validation set. Conclusions: We demonstrate the viability of in-vivo LEBS measurement of histologically normal rectal mucosa to predict the presence of clinically relevant adenomas throughout the colon. The current work represents the next step in the development of rectal LEBS as a tool for colorectal cancer risk stratification
West Nile Virus Surveillance, Guadeloupe, 2003â2004
We conducted extensive surveillance for West Nile virus infection in equines and chickens in Guadeloupe in 2003â2004. We showed a high seroprevalence in equines in 2003 related to biome, followed by a major decrease in virus circulation in 2004. No human or equine cases were reported during the study
Cognitive facilitation following intentional odor exposure
This paper reviews evidence that, in addition to incidental olfactory pollutants, intentional odor delivery can impact cognitive operations both positively and negatively. Evidence for cognitive facilitation/interference is reviewed alongside four potential explanations for odor-induced effects. It is concluded that the pharmacological properties of odors can induce changes in cognition. However, these effects can be accentuated/attenuated by the shift in mood following odor exposure, expectancy of cognitive effects, and cues to behavior via the contextual association with the odor. It is proposed that greater consideration is required in the intentional utilization of odors within both industrial and private locations, since differential effects are observed for odors with positive hedonic qualities
High-throughput identification of genotype-specific cancer vulnerabilities in mixtures of barcoded tumor cell lines.
Hundreds of genetically characterized cell lines are available for the discovery of genotype-specific cancer vulnerabilities. However, screening large numbers of compounds against large numbers of cell lines is currently impractical, and such experiments are often difficult to control. Here we report a method called PRISM that allows pooled screening of mixtures of cancer cell lines by labeling each cell line with 24-nucleotide barcodes. PRISM revealed the expected patterns of cell killing seen in conventional (unpooled) assays. In a screen of 102 cell lines across 8,400 compounds, PRISM led to the identification of BRD-7880 as a potent and highly specific inhibitor of aurora kinases B and C. Cell line pools also efficiently formed tumors as xenografts, and PRISM recapitulated the expected pattern of erlotinib sensitivity in vivo
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