1,620 research outputs found
A 3+1 Decomposition of the Minimal Standard-Model Extension Gravitational Sector
The 3+1 (ADM) formulation of General Relativity is used in, for example,
canonical quantum gravity and numerical relativity. Here we present a 3+1
decomposition of the minimal Standard-Model Extension gravity Lagrangian. By
choosing the leaves of foliation to lie along a timelike vector field we write
the theory in a form which will allow for comparison and matching to other
gravity models.Comment: Presented at the Eighth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, May 12-16, 201
Epidemiology and Natural History of Human Papillomavirus Infections in the Female Genital Tract
Human papillomavirus (HPV) is the most common newly diagnosed sexually transmitted infection in the United States. Although the majority of sexually active adults will be infected with HPV at least once in their lives, it is sexually active women less than 25 years of age who consistently have the highest rates of infection. Besides youth and gender, common risk factors for HPV infection and clinical sequelae of infection include high number of sexual partners and coinfection with Chlamydia trachomatis or herpes simplex virus. Most HPV infections are cleared by the immune system and do not result in clinical complications. Clinical sequelae in cases of low-risk HPV infection consist of genital warts, and clinical manifestations of high-risk HPV infection include abnormal Pap test results, low-grade squamous intraepithelial lesions (LSIL), high-grade squamous intraepithelial lesions (HSIL), and cervical cancer. LSIL, HSIL, and cervical cancer carry significant morbidity and/or mortality; genital warts and abnormal Pap test results are often significant sources of psychosocial distress. Currently, there are neither effective means of preventing HPV transmission nor cures for clinical manifestations: infection can only be prevented via complete sexual abstinence, while treatment for clinical sequelae such as genital warts and cytologic abnormalities consists of removing the problematic cells and watching for recurrence; this method consumes significant health care resources and is costly. New prophylactic HPV vaccines promise to dramatically reduce the incidence of HPV infection, genital warts, and cytologic abnormalities
Effects of Dynamic Cycling on Motor Function, Gait, and Balance in Individuals with Parkinson\u27s Disease
Please see the pdf version of the abstract
Ubiquitous energy storage
This paper presents a vision of a future power system with "ubiquitous energy storage", where storage would be utilized at all levels of the electricity system. The growing requirement for storage is reviewed, driven by the expansion of distributed generation. The capabilities and existing applications of various storage technologies are presented, providing a useful review of the state of the art. Energy storage will have to be integrated with the power system and there are various ways in which this may be achieved. Some of these options are discussed, as are commercial and regulatory issues. In two case studies, the costs and benefits of some storage options are assessed. It is concluded that electrical storage is not cost effective but that thermal storage offers attractive opportunities
EVENTS AFTER THE BINDING OF ANTIGEN TO LYMPHOCYTES : REMOVAL AND REGENERATION OF THE ANTIGEN RECEPTOR
The behavior of the immunoglobulin antigen receptor on lymphocytes was studied using both fluorescent antiimmunoglobulin antibody to detect B cells and autoradiography with radiolabeled antigens to detect antigen-binding cells. It was shown that after binding of antiimmunoglobulin antibody to the lymphocyte there was a rapid loss of surface immunoglobulin and then a progressive reappearance over 18 h. This could be quantitated using an inhibition assay for surface immunoglobulin. Similarly, after binding various dinitrophenyl-conjugated proteins or keyhole limpet hemocyanin to their specific antigen-binding cells, there was a loss of the antigen receptor from the surface and then a progressive reappearance of the receptor. The reappearance of surface immunoglobulin and of the antigen receptor proceeded at about the same rate. Repeated exposure to antibody or prolonged exposure to antigen did not diminish the capacity of the lymphocyte to re-express its receptor. These events, which follow the interaction of antigen and its receptor, are of possible importance in understanding the mechanism of triggering of the immune response and of tolerance
Big Bend National Park Biosphere Reserve: A History of Scientific Study - Volume I: A Narrative Description of Scientific Study
In 1971 the United Nations Educational, Scientific, and Cultural Organization (UNESCO) created the Man and the Biosphere (MAB) Program for the purpose of promoting rational use of the earth\u27s resources. Formal involvement by the U.S. began in 1974. By 1976, 28 biosphere reserves had been selected in the U.S., including Big Bend National Park (BBNP) (Fig. 1). The purpose of this 2-volume report was to provide an interdisciplinary reference volume of literature citations for BBNP and the surrounding Chihuahuan Desert, and to provide a synopsis of research completed at BBNP
Evidence that avian reovirus ĻNS is an RNA chaperone: implications for genome segment assortment.
Reoviruses are important human, animal and plant pathogens having 10-12 segments of double-stranded genomic RNA. The mechanisms controlling the assortment and packaging of genomic segments in these viruses, remain poorly understood. RNA-protein and RNA-RNA interactions between viral genomic segment precursors have been implicated in the process. While non-structural viral RNA-binding proteins, such as avian reovirus ĻNS, are essential for virus replication, the mechanism by which they assist packaging is unclear. Here we demonstrate that ĻNS assembles into stable elongated hexamers in vitro, which bind single-stranded nucleic acids with high affinity, but little sequence specificity. Using ensemble and single molecule fluorescence spectroscopy, we show that ĻNS also binds to a partially double-stranded RNA, resulting in gradual helix unwinding. The hexamer can bind multiple RNA molecules and exhibits strand-annealing activity, thus mediating conversion of metastable, intramolecular stem-loops into more stable heteroduplexes. We demonstrate that the ARV ĻNS acts as an RNA chaperone facilitating specific RNA-RNA interactions between genomic precursors during segment assortment and packaging
Does Rubella Immunity Predict Measles Immunity? A Serosurvey of Pregnant Women
Background. This study was undertaken to determine whether rubella immunity infers measles immunity in pregnant women. Methods. Stored serum samples were obtained from the Iowa State Hygienic Laboratory for evaluation of rubella and measles immunities with IgG enzyme-linked immunosorbent assay. Results. Nine hundred serum samples were obtained for testing. The average age of the women at the time of antepartum serum collection was 28 (range, 14 to 44) years. Measles and rubella immunity were 88% and 98%, respectively; there was no effect of immunity status by age identified. Eighty eight percent of those with rubella immunity were also measles immune. There was no association between paired rubella and measles immunity identified, P < .0001. Discussion. Known rubella immunity did not infer measles immunity in our population. Thus, we recommend that pregnant women exposed to measles be tested and appropriately treated if they are found to be nonimmune
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