15,616 research outputs found
The case for new academic workspaces
Executive summary: This report draws upon the combined efforts of
a number of estates professionals, architects,
academics, designers, and senior managers
involved in the planning of new university buildings
for the 21st century. Across these perspectives,
all would agree – although perhaps for different
reasons - that this planning is difficult and that a
number of particular considerations apply in the
design of academic workspaces. Despite these
difficulties, they will also agree that when this
planning goes well, ‘good’ buildings are truly
transformational – for both the university as a
whole and the people who work and study in them.
The value of well-designed buildings goes far
beyond their material costs, and endures long after
those costs have been forgotten ..
Expanding the Realm of Microlensing Surveys with Difference Image Photometry
We present a new technique for monitoring microlensing activity even in
highly crowded fields, and use this technique to place limits on low-mass
MACHOs in the haloes of M31 and the Galaxy. Unlike present Galactic
microlensing surveys, we employ a technique in which a large fraction of the
stellar sample is compressed into a single CCD field, rather than spread out in
a way requiring many different telescope pointings. We implement the suggestion
by Crotts (1992) that crowded fields can be monitored by searching for changes
in flux of variable objects by subtracting images of the same field, taken in
time sequence, positionally registered, photometrically normalized, then
subtracted from one another (or a sequence average). The present work tackles
the most difficult part of this task, the adjustment of the point spread
function among images in the sequence so that seeing variations play an
insignificant role in determining the residual after subtraction. The
interesting signal following this process consists of positive and negative
point sources due to variable sources. The measurement of changes in flux
determined in this way we dub "difference image photometry" (also called "pixel
lensing" [Gould 1996]). - The matching of the image point spread function (PSF)
is accomplished by a division of PSFs in Fourier space to produce a convolution
kernel, in a manner explored for other reasons by Phillips & Davis (1995). In
practice, we find the application of this method is difficult in a typical
telescope and wide field imaging camera due to a subtle interplay between the
spatial variation of the PSF associated with the optical design and the
inevitable time variability of the telescope focus. Such effects lead to
complexities...(abstract continues)Comment: Astronomical Journal, in press (accepted 10 Jul 1996), 49 pages,
Latex 4 requires .sty files, 12 figure
Towards practical classical processing for the surface code
The surface code is unarguably the leading quantum error correction code for
2-D nearest neighbor architectures, featuring a high threshold error rate of
approximately 1%, low overhead implementations of the entire Clifford group,
and flexible, arbitrarily long-range logical gates. These highly desirable
features come at the cost of significant classical processing complexity. We
show how to perform the processing associated with an nxn lattice of qubits,
each being manipulated in a realistic, fault-tolerant manner, in O(n^2) average
time per round of error correction. We also describe how to parallelize the
algorithm to achieve O(1) average processing per round, using only constant
computing resources per unit area and local communication. Both of these
complexities are optimal.Comment: 5 pages, 6 figures, published version with some additional tex
Vascular Dysfunction and Posttraumatic Stress Disorder: Examining the Role of Oxidative Stress and Sympathetic Activity
Purpose: The physiological manifestations of posttraumatic stress disorder (PTSD) have been associated with an increase in risk of cardiovascular disease (CVD) independent of negative lifestyle factors. The goal of the study was to better elucidate the mechanisms behind the increased CVD risk by examining peripheral vascular function, a precursor to CVD. Moreover, this study sought to determine the role of oxidative stress and sympathetic nervous system (SNS) activity in PTSD-induced vascular dysfunction.
Methods: Sixteen individuals with PTSD (10 women, 6 men; age 24 ± 4 years), and twenty-four healthy controls (CTRL; 15 women, 9 men, 24 ± 4 years), participated in the study. The PTSD group participated in two visits, consuming either a placebo or antioxidant cocktail (AO - vitamins C and E and alpha lipoic acid) prior to their visits, in a randomized order. Arm vascular function was assessed via the reactive hyperemia- induced flow mediated dilation of the brachial artery (BAFMD) technique and evaluated with Doppler ultrasonography. Brachial artery and arm microvascular function were determined by percent change of diameter from baseline normalized for BA shear rate (BAD/Shear), and blood flow area under the curve (BF AUC), respectively. Heart rate variability (HRV) was used to assess autonomic nervous system activity.
Results: BF AUC was significantly lower (p = 0.02) and SNS activity was significantly higher (p = 0.02) in the PTSD group when compared to the CTRL group. BAD/Shear was not different between groups. Following the acute AO supplementation, BF AUC was augmented to which it was no longer significantly different (p = 0.16) when compared to the CTRL group. SNS activity within the PTSD group was significantly reduced (p=.007) following the AO supplementation when compared to the PL condition, and the difference between PTSD and CTRL was no longer significant (p=.41).
Conclusion: Young individuals with PTSD demonstrated lower arm microvascular, but not brachial artery, function as well as higher sympathetic activity when compared to healthy controls matched for age, sex, and physical activity level. Furthermore, this microvascular dysfunction and SNS activity was attenuated by an acute AO supplementation to the level of the healthy controls. Taken together, this study revealed that the modulation of oxidative stress, via an acute AO supplementation, improved vascular dysfunction in individuals with PTSD, potentially by reducing the substantial SNS activity associated with this disorder.https://scholarscompass.vcu.edu/gradposters/1084/thumbnail.jp
Mapping the coevolution of urban energy systems: pathways of change
Abstract. The interface of a long-standing movement for sustainability at the urban scale
and the imperatives of the carbon-reduction agenda are driving change in urban energy
systems. This paper seeks to address the nature of that change and, in particular, to consider
how different pathways of change are emerging. To do this it draws on the coevolution and
pathways literatures to interrogate a database of current urban energy initiatives within
the UK. This analysis reveals the multiple pathways of change though which new modes
of energy production and consumption are being developed to deliver carbon reductions
through the reconfiguring of urban energy systems. The paper concludes with a discussion
of the implications of these changes for urban governance and for carbon reductions
Post-Traumatic Stress and Academic Performance Among Entry-Level Doctoral Physical Therapy Students in a Human Anatomy Cadaver Dissection Course
Background: Dissection of human cadavers can be a stressful experience for students. Purpose: The purposes of this study were twofold: 1) to determine if physical therapy students develop or experience a worsening of post-traumatic stress disorder (PTSD) symptoms during exposure to and dissection of human cadavers; and 2) to determine if these symptoms are related to academic performance. Methods: Previous history of a diagnosis of anxiety or post-traumatic stress disorder and level of prior exposure to cadavers were recorded among 26 entry-level first semester doctoral students in physical therapy (DPT) taking gross human anatomy. Their level of anxiety about working with cadavers before and after the course was recorded. The Life Events Checklist (LEC-5) for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) was used as a self-report measure to record potentially traumatic events in a subject’s life prior to the study and during the course. Subjects also completed the Post-Traumatic Stress Disorder Checklist (PCL-5) at the beginning and end of the course to assess for symptoms of post-traumatic stress disorder. Student performance was assessed using written and practical examination grades. Results: Overall, the PCL-5 score for the group decreased significantly over the semester (p = 0.01). However, 3 subjects’ PCL-5 scores increased. Risk factors present among these subjects included previous diagnosis of post-traumatic stress disorder or anxiety, combat exposure, history of physical or sexual abuse, lack of previous exposure to cadavers, and coinciding traumatic events. Written examination performance was not significantly related to either change in PCL-5 (p = 0.84) or post-PCL-5 (p = 0.69) scores. Practical examination performance was not significantly related to either change in PCL-5 (p = 0.28) or post-PCL-5 (p = 0.51) scores. However, consistent with previous research, students with a history of post-traumatic stress disorder and/or anxiety did have statistically significant lower written examination scores. Conclusions: Physical therapy students neither developed nor experienced a worsening of, but rather a reduction in, PTSD symptoms during exposure to and dissection of human cadavers. Overall, symptoms of PTSD did not seem to be related to academic performance
SSL: A software specification language
SSL (Software Specification Language) is a new formalism for the definition of specifications for software systems. The language provides a linear format for the representation of the information normally displayed in a two-dimensional module inter-dependency diagram. In comparing SSL to FORTRAN or ALGOL, it is found to be largely complementary to the algorithmic (procedural) languages. SSL is capable of representing explicitly module interconnections and global data flow, information which is deeply imbedded in the algorithmic languages. On the other hand, SSL is not designed to depict the control flow within modules. The SSL level of software design explicitly depicts intermodule data flow as a functional specification
Effects of Carbon Dioxide on Glucose Incorporation in Flatworms
Paper by James S. McDaniel, Austin J. MacInnis, and Clark P. Rea
Introduction to the Analysis of Survival Data in the Presence of Competing Risks
Competing risks occur frequently in the analysis of survival data. A competing risk is an event whose occurrence precludes the occurrence of the primary event of interest. In a study examining time to death attributable to cardiovascular causes, death attributable to noncardiovascular causes is a competing risk. When estimating the crude incidence of outcomes, analysts should use the cumulative incidence function, rather than the complement of the Kaplan-Meier survival function. The use of the Kaplan-Meier survival function results in estimates of incidence that are biased upward, regardless of whether the competing events are independent of one another. When fitting regression models in the presence of competing risks, researchers can choose from 2 different families of models: modeling the effect of covariates on the cause-specific hazard of the outcome or modeling the effect of covariates on the cumulative incidence function. The former allows one to estimate the effect of the covariates on the rate of occurrence of the outcome in those subjects who are currently event free. The latter allows one to estimate the effect of covariates on the absolute risk of the outcome over time. The former family of models may be better suited for addressing etiologic questions, whereas the latter model may be better suited for estimating a patient’s clinical prognosis. We illustrate the application of these methods by examining cause-specific mortality in patients hospitalized with heart failure. Statistical software code in both R and SAS is provided
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