428 research outputs found
Hope and academic performance in a higher education residence context
The study sought to explore the relationship between trait hope, environmental hope, academic performance and demographics (language, gender, year of study & race) in university residence students in a South African Higher Education Residence setting. Using four scales including: (1) the Trait Hope Scale (2) the Environmental Hope Scale (3) the Australian modification of the Hope Scale; (4) and the Residence Environmental Hope Scale, the research aimed to broadly investigate two correlative relationships. The relationships included: (i) The relationship between levels of trait hope and academic performance, (ii) the relationship between environmental levels of hope and academic performance. In addition to a quantitative approach a qualitative approach was added. Cultural Historical Activity Theory was applied to an analysis of the residence system at the University of Cape Town. A combination of quantitative and qualitative results suggested that there were minimal links between hope and academic performance at both a dispositional and environmental hope level. Third generation activity theory was used as a methodological approach to obtain a greater understanding of residence studentsā experience. The analysis provided an interpretation as to why residences minimally facilitated studentsā hope towards the pursuit of their university degree. The purpose of the residence system came into question. Several qualitative themes emerged on ways to cultivate hope, agency and pathways in a residence higher education context in the future. This interfaced with a Cultural Historical Activity Theory analysis which revealed several fundamental contradictions and tensions. The conclusion of the thesis pointed towards (ii) hope theory being critiqued for having limited application in a higher education context and (ii) an identified need (revealed through several systemic contradictions) to re-clarify, reconfigure and increase a shared understanding of the purpose of the residence syste
One-dimensional reflection by a semi-infinite periodic row of scatterers
AbstractThree methods are described in order to solve the canonical problem of the one-dimensional reflection by a semi-infinite periodic row of identical scatterers. The exact reflection coefficient R is determined. The first method is associated with shifting the domain by a single period and subsequently considering two scatterers, one being a single scatterer and the second being the entire semi-infinite array. The second method determines the reflection coefficient RN associated with a finite array of N scatterers. The limit as Nāā is then taken. In general RN does not converge to R in this limit, although we summarize various arguments that can be made to ensure the correct limit is achieved. The third method considers direct approaches. In particular, for point masses, the governing inhomogeneous ordinary differential equation is solved using the discrete WienerāHopf technique
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Critical Race Theory, Columbia Law School and the Legacies of Slavery: The Black Male Initiative
This episode examines Columbia Law Schoolās history and legacy of slavery and the extent to which the remnants of that legacy reverberate throughout our campus today. With a specific lens on the experiences of Black men on campus and in the wider society, we draw parallels between the hyper surveillance and vilification experienced by Frederick Wells on the law schoolās campus in 1924 and the experiences of Black male students on and off campus in recent years
The Yin and Yang actions of North American ginseng root in modulating the immune function of macrophages
<p>Abstract</p> <p>Background</p> <p>Immuno-modulatory effects of ginseng, including both immuno-stimulatory and immuno-suppressive effects, have been widely reported. This study aims to determine whether the paradoxical immuno-modulatory effect is related to unique phytochemical profiles of different North American (NA) ginseng, namely aqueous (AQ) and alcoholic (ALC) extracts.</p> <p>Methods</p> <p>AQ and ALC extracts were prepared and their immuno-bioactivity were studied <it>in vitro </it>in murine macrophages (Raw 264.7) through measuring the direct stimulatory production of pro-inflammatory mediator and cytokines as well as the suppression of lipopolysaccharide (LPS)-stimulatory response by the two extracts. Gel permeation chromatography was used to fractionate and isolate phytochemicals for characterization of ginseng extracts.</p> <p>Results</p> <p>AQ extract up-regulated the production of nitric oxide (NO), tumour necrosis factor-Ī± (TNF-Ī±) and interleukin-6 (IL-6) while ALC extract did not. ALC extract but not AQ extract suppressed LPS-induced macrophage NO and TNF-Ī± production. These immuno-stimulatory and suppressive effects were exhibited at similar extract concentrations. Moreover, the macrophage-stimulating activity of the AQ extract was inhibited in the presence of ALC extract. Fractionation of AQ extract revealed the presence of two major peaks at 230 nm with average molecular weights of 73,000 and 37,000 Da. The first fraction had similar elution volume as the crude polysaccharide (PS) fraction isolated from the AQ extract, and it was the only bioactive species. Parallel fractionation study of ALC extract yielded similar elution profiles; however, both sub-fractions were devoid of PS. Fraction I of the ALC extract suppressed LPS-induced NO production dose-dependently.</p> <p>Conclusion</p> <p>ALC extract of NA ginseng, which was devoid of PS, was immuno-inhibitory whereas the AQ extract, which contained PS, was immuno-stimulatory. These extract-related anti-inflammatory and pro-inflammatory effects may be considered as the Yin and Yang actions of ginseng.</p
The relative importance of electron-electron interactions compared to disorder in the two-dimensional "metallic" state
The effect of substrate bias and surface gate voltage on the low temperature
resistivity of a Si-MOSFET is studied for electron concentrations where the
resistivity increases with increasing temperature. This technique offers two
degrees of freedom for controlling the electron concentration and the device
mobility, thereby providing a means to evaluate the relative importance of
electron-electron interactions and disorder in this so-called ``metallic''
regime. For temperatures well below the Fermi temperature, the data obey a
scaling law where the disorder parameter (), and not the
concentration, appears explicitly. This suggests that interactions, although
present, do not alter the Fermi-liquid properties of the system fundamentally.
Furthermore, this experimental observation is reproduced in results of
calculations based on temperature-dependent screening, in the context of
Drude-Boltzmann theory.Comment: 5 pages, 6 figure
Adiponectin DNA methylation in South African women with gestational diabetes mellitus : effects of HIV infection
DNA methylation is increasingly recognized as a potential biomarker of metabolic disease.
However, there is limited information on the impact of human immunodeficiency virus (HIV)
infection on the candidacy of DNA methylation to serve as molecular biomarkers. This study
investigated the effect of HIV infection on DNA methylation patterns in the peripheral blood
of South African women with (n = 95) or without (n = 191) gestational diabetes mellitus
(GDM). DNA methylation levels at eight CpG sites in the adiponectin gene (ADIPOQ) promoter were measured using bisulfite conversion and pyrosequencing. Differences between
HIV negative (
-
) and positive (
+
) women were observed. In HIVwomen, methylation at CpG
-3400 was lower in GDM+ women compared to those with normoglycemia (8.5-fold; p =
0.004), and was associated with higher fasting glucose (Ī²-co-efficient = 0.973; p = 0.006)
and lower adiponectin (Ī²-co-efficient = -0.057; p = 0.014) concentrations. These associations were not observed in HIV+ women. In silico analysis showed that Transcription Factor
AP2-alpha is able to bind to the altered CpG site, suggesting that CpG -3400 may play a
functional role in the regulation of ADIPOQ expression. Our findings show that DNA methylation differs by HIV status, suggesting that HIV infection needs to be taken into consideration in studies exploring DNA methylation as a biomarker of GDM in high HIV prevalence
settings.http://www.plosone.orgpm2022Internal MedicineObstetrics and Gynaecolog
Event Horizons in Numerical Relativity I: Methods and Tests
This is the first paper in a series on event horizons in numerical
relativity. In this paper we present methods for obtaining the location of an
event horizon in a numerically generated spacetime. The location of an event
horizon is determined based on two key ideas: (1) integrating backward in time,
and (2) integrating the whole horizon surface. The accuracy and efficiency of
the methods are examined with various sample spacetimes, including both
analytic (Schwarzschild and Kerr) and numerically generated black holes. The
numerically evolved spacetimes contain highly distorted black holes, rotating
black holes, and colliding black holes. In all cases studied, our methods can
find event horizons to within a very small fraction of a grid zone.Comment: 22 pages, LaTeX with RevTeX 3.0 macros, 20 uuencoded gz-compressed
postscript figures. Also available at http://jean-luc.ncsa.uiuc.edu/Papers/
Submitted to Physical Review
Spatial Coherence of a polariton condensate in 1D acoustic lattice
Several mechanisms are discussed which could determine the spatial coherence
of a polariton condensate confined to a one dimensional wire. The mechanisms
considered are polariton-polariton interactions, disorder scattering and
non-equilibrium occupation of finite momentum modes. For each case, the shape
of the resulting spatial coherence function g1(x) is analysed. The results are
compared with the experimental data on a polariton condensate in an acoustic
lattice from [E. A. Cerda-Mendez et al, Phys. Rev. Lett. 105, 116402 (2010)].
It is concluded that the shape of g1(x) can only be explained by
non-equilibrium effects, and that ~10 modes are occupied in the experimental
system.Comment: 6 pages, 4 figure
Event Horizons in Numerical Relativity II: Analyzing the Horizon
We present techniques and methods for analyzing the dynamics of event
horizons in numerically constructed spacetimes. There are three classes of
analytical tools we have investigated. The first class consists of proper
geometrical measures of the horizon which allow us comparison with perturbation
theory and powerful global theorems. The second class involves the location and
study of horizon generators. The third class includes the induced horizon
2-metric in the generator comoving coordinates and a set of membrane-paradigm
like quantities. Applications to several distorted, rotating, and colliding
black hole spacetimes are provided as examples of these techniques.Comment: 23 double column pages including 28 figures. Higher quality figures
(big size!) available upon request (jmasso OR [email protected]
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