704 research outputs found
Classification of Cohomogeneity One Manifolds in Low Dimensions
A cohomogeneity one manifold is a manifold with the action of a compact Lie
group, whose quotient is one dimensional. Such manifolds are of interest in
Riemannian geometry, in the context of nonnegative sectional curvature, as well
as in other areas of geometry and in physics. In this paper we classify compact
simply connected cohomogeneity one manifolds in dimensions 5, 6 and 7. We also
show that all such manifolds admit metrics of nonnegative sectional curvature,
with the possible exception of two families of manifolds
Cyberbullying : a preventative method
A new means of bullying has been created through the usage of cell phones, pagers, and the internet. Cyberbullying is an aggressive act intended to harm another and is repeated over a duration of time. It involves using digital communication devices to target victims. As a newer phenomenon, the research on cyberbullying is limited. However, the research that has been conducted suggests that cyberbullying is a great cause of concern among our youth today and is an issue that needs to be addressed. A four lesson guidance unit addressing cyberbullying was developed. This unit focuses on creating awareness and educating students in hopes of preventing the occurrence of cyberbullying in the future
Effect of genital herpes on cervicovaginal HIV shedding in women co-infected with HIV AND HSV-2 in Tanzania.
To compare the presence and quantity of cervicovaginal HIV among HIV seropositive women with clinical herpes, subclinical HSV-2 infection and without HSV-2 infection respectively; to evaluate the association between cervicovaginal HIV and HSV shedding; and identify factors associated with quantity of cervicovaginal HIV.
Four groups of HIV seropositive adult female barworkers were identified and examined at three-monthly intervals between October 2000 and March 2003 in Mbeya, Tanzania: (1) 57 women at 70 clinic visits with clinical genital herpes; (2) 39 of the same women at 46 clinic visits when asymptomatic; (3) 55 HSV-2 seropositive women at 60 clinic visits who were never observed with herpetic lesions; (4) 18 HSV-2 seronegative women at 45 clinic visits. Associations of genital HIV shedding with HIV plasma viral load (PVL), herpetic lesions, HSV shedding and other factors were examined.
Prevalence of detectable genital HIV RNA varied from 73% in HSV-2 seronegative women to 94% in women with herpetic lesions (geometric means 1634 vs 3339 copies/ml, p = 0.03). In paired specimens from HSV-2 positive women, genital HIV viral shedding was similar during symptomatic and asymptomatic visits. On multivariate regression, genital HIV RNA (log10 copies/mL) was closely associated with HIV PVL (β = 0.51 per log10 copies/ml increase, 95%CI:0.41-0.60, p<0.001) and HSV shedding (β = 0.24 per log10 copies/ml increase, 95% CI:0.16-0.32, p<0.001) but not the presence of herpetic lesions (β = -0.10, 95%CI:-0.28-0.08, p = 0.27).
HIV PVL and HSV shedding were more important determinants of genital HIV than the presence of herpetic lesions. These data support a role of HSV-2 infection in enhancing HIV transmissibility
A Practical Approach to Incorporating ESG Risk Into Equity Valuation
The rise in the capital allocated and investor focus attributed to ESG investing over the past several years has been significant. However, the current literature is not settled regarding the value that ESG risk measures and reporting has on investments and valuations. If this risk is essential, then this risk should be incorporated to account for the presence or the lack of ESG-related risk in valuation models. However, with the relative newness and difficulty of quantifying ESG risk, there is little practical guidance on incorporating this risk into valuation estimates. We provide evidence that ESG-related risk scores are positively associated with the cost of equity. Building upon that result, we operationalize the positive relationship to adjust the cost of equity in free cash flow to equity valuation models. Firms with higher ESG risk have a higher required return, while firms with lower ESG risk have a lower discount rate. Our approach is a practical guide for investors and analysts to account for ESG risk adjustments in valuation models
A Dataset of Anatomical Environments for Medical Robots: Modeling Respiratory Deformation
Anatomical models of a medical robot's environment can significantly help
guide design and development of a new robotic system. These models can be used
for benchmarking motion planning algorithms, evaluating controllers, optimizing
mechanical design choices, simulating procedures, and even as resources for
data generation. Currently, the time-consuming task of generating these
environments is repeatedly performed by individual research groups and rarely
shared broadly. This not only leads to redundant efforts, but also makes it
challenging to compare systems and algorithms accurately. In this work, we
present a collection of clinically-relevant anatomical environments for medical
robots operating in the lungs. Since anatomical deformation is a fundamental
challenge for medical robots operating in the lungs, we describe a way to model
respiratory deformation in these environments using patient-derived data. We
share the environments and deformation data publicly by adding them to the
Medical Robotics Anatomical Dataset (Med-RAD), our public dataset of anatomical
environments for medical robots
Monitoring CD27 expression to evaluate Mycobacterium tuberculosis activity in HIV-1 infected individuals in vivo.
The level of bacterial activity is only poorly defined during asymptomatic Mycobacterium tuberculosis (MTB) infection. The objective was to study the capacity of a new biomarker, the expression of the T cell maturation marker CD27 on MTB-specific CD4 T cells, to identify active tuberculosis (TB) disease in subjects from a MTB and HIV endemic region. The frequency and CD27 expression of circulating MTB-specific CD4 T cells was determined in 96 study participants after stimulation with purified protein derivative (PPD) using intracellular cytokine staining for IFNgamma (IFNγ). Subjects were then stratified by their TB and HIV status. Within PPD responders, a CD27(-) phenotype was associated with active TB in HIV(-) (p = 0.0003) and HIV(+) (p = 0.057) subjects, respectively. In addition, loss of CD27 expression preceded development of active TB in one HIV seroconverter. Interestingly, in contrast to HIV(-) subjects, MTB-specific CD4 T cell populations from HIV(+) TB-asymptomatic subjects were often dominated by CD27(-) cells. These data indicate that down-regulation of CD27 on MTB-specific CD4 T cell could be used as a biomarker of active TB, potentially preceding clinical TB disease. Furthermore, these data are consistent with the hypothesis that late, chronic HIV infection is frequently associated with increased mycobacterial activity in vivo. The analysis of T cell maturation and activation markers might thus be a useful tool to monitor TB disease progression
Salinity and Livestock Water Quality
Experiments with albino rates were undertaken preliminary to work with large animals. The purpose here was two-fold: (1) to compare several kinds of salts and get some idea of their relative toxicities; and (2) to establish what concentrations of salts would be best used in experimental work with large animals
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