264 research outputs found
Geometric realizations of generalized algebraic curvature operators
We study the 8 natural GL equivariant geometric realization questions for the
space of generalized algebraic curvature tensors. All but one of them is
solvable; a non-zero projectively flat Ricci antisymmetric generalized
algebraic curvature is not geometrically realizable by a projectively flat
Ricci antisymmetric torsion free connection
Probabilistic Estimation of Site Specific Fault Displacements
The College of the Redwoods (CR) located near Eureka, California would like to upgrade a series of existing buildings that are unfortunately located on secondary faults associated with the active Little Salmon Fault (LSF) zone. In the early 1990âs a deterministic value of the maximum dip-slip displacement that had occurred on one of these secondary faults located beneath the southeast building corner of the former library was measured to be 1.7 feet. This displacement was resolved into approximately 1.5 feet horizontal offset and 0.8 feet of vertical offset, based on the secondary fault plane dip. Geologically, it has not been possible to establish the actual dates of the occurrence of the displacements on the observed faults, therefore it was assumed that they all had occurred within the last 11,000 years. The structural engineer for the project has indicated that it was not possible to design for the observed ground displacement of 1.7 feet. This limited study was undertaken to assess the variation of ground displacements that were observed over the area of ground occupied by CRâs Administration, Science, and former Library buildings. The purpose of this study was to evaluate the reasonableness of using a deterministically determined maximum value of displacement in estimating, and designing mitigations for, the structural response, or whether a probabilistic approach could be utilized. The only data available within the limited time frame allowed for the study was from a series of trench logs made as part of a project for locating building sites on the campus in the early 1990âs. As a first step the frequency distributions of both horizontal and vertical displacements located in a volume of soil comprising the area occupied by the above buildings to a depth of 14 feet were examined. The 14 feet was the maximum depth of the trenches used to provide data for the study. Probability density functions (PDF) versus displacements were developed based on the frequency distributions. The area under the PDF curves between given displacement intervals represents the probability of occurrence (POC) of that displacement. A cumulative probability of occurrence for a displacement interval can be determined by adding the individual POCâs. Based on this it was estimated that a horizontal displacement of †1.0 foot has a probability of 89% of occurring in the next 11,000 years at the site. In contrast, a vertical displacement of †1.0 foot has a probability of 88% probability of occurrence
Unusual characteristics of Codium fragile chloroplast DNA revealed by physical and gene mapping
A complete physical map of the Codium fragile chloroplast genome was constructed and the locations of a number of chloroplast genes were determined. Several features of this circular genome are unusual. At 89 kb in size, it is the smallest chloroplast genome known. Unlike most chloroplast genomes it lacks any large repeat elements. The 8 kb spacer region between the 16 S and 23 S rRNA genes is the largest such spacer characterized to date in chloroplast DNA. This spacer region is also unusual in that it contains the rps 12 gene or at least a portion thereof. Three regions polymorphic for size are present in the Codium chloroplast genome. The psb A and psb C genes map closely to one of these regions, another region is in the spacer between the 16 S and 23 S rRNA genes and the third is very close to or possibly within the 16 S rRNA gene. The gene order in the Codium genome bears no marked resemblance to either the âconsensusâ vascular plant order or to that of any green algal or bryophyte genome.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47569/1/438_2004_Article_BF00334385.pd
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Differential item functioning for items in Berger's HIV Stigma Scale: an analysis of cohorts from the Indian, Swedish, and US contexts
PURPOSE: To examine whether items in Berger's HIV Stigma Scale function differently with persons of different age, gender, and cultural backgrounds.
METHODS: Secondary data from cohorts, collected in South India (nâ=â250), Sweden (nâ=â193), and the US (nâ=â603) were reanalyzed to evaluate DIF within, between, and across these cohorts. All participants had answered the revised version of the HIV stigma scale consisting of 32 items forming the subscales Personalized stigma, Disclosure concerns, Concerns about public attitudes, and Negative self-image. Differential Item Functioning (DIF) for these items was assessed using hybrid ordinal regression-IRT technique. When DIF was detected, the cumulative impact of DIF on individual subscale scores was evaluated.
RESULTS: DIF was detected for 9 items within, between, or across cohorts, but the DIF was negligible in general. Detected DIF between the Swedish and Indian cohorts had a cumulative salient impact on individual scores for the subscale Disclosure Concerns; Disclosure concerns were overestimated in the Swedish cohort and both over- and underestimated in the Indian cohort.
CONCLUSIONS: The items in the 32-item version of the HIV stigma scale did not seem to be particularly prone to present DIF. The DIF between the Indian and Swedish cohort for items in the subscale Disclosure Concerns could, however, result in both type I and type II errors if scores should be compared between the Indian and Swedish cohort
Recommended from our members
Differential item functioning for items in Berger's HIV Stigma Scale: an analysis of cohorts from the Indian, Swedish, and US contexts
PURPOSE: To examine whether items in Berger's HIV Stigma Scale function differently with persons of different age, gender, and cultural backgrounds. METHODS: Secondary data from cohorts, collected in South India (nâ=â250), Sweden (nâ=â193), and the US (nâ=â603) were reanalyzed to evaluate DIF within, between, and across these cohorts. All participants had answered the revised version of the HIV stigma scale consisting of 32 items forming the subscales Personalized stigma, Disclosure concerns, Concerns about public attitudes, and Negative self-image. Differential Item Functioning (DIF) for these items was assessed using hybrid ordinal regression-IRT technique. When DIF was detected, the cumulative impact of DIF on individual subscale scores was evaluated. RESULTS: DIF was detected for 9 items within, between, or across cohorts, but the DIF was negligible in general. Detected DIF between the Swedish and Indian cohorts had a cumulative salient impact on individual scores for the subscale Disclosure Concerns; Disclosure concerns were overestimated in the Swedish cohort and both over- and underestimated in the Indian cohort. CONCLUSIONS: The items in the 32-item version of the HIV stigma scale did not seem to be particularly prone to present DIF. The DIF between the Indian and Swedish cohort for items in the subscale Disclosure Concerns could, however, result in both type I and type II errors if scores should be compared between the Indian and Swedish cohort
Bigger, Better, Faster, More at the LHC
Multijet plus missing energy searches provide universal coverage for theories
that have new colored particles that decay into a dark matter candidate and
jets. These signals appear at the LHC further out on the missing energy tail
than two-to-two scattering indicates. The simplicity of the searches at the LHC
contrasts sharply with the Tevatron where more elaborate searches are necessary
to separate signal from background. The searches presented in this article
effectively distinguish signal from background for any theory where the LSP is
a daughter or granddaughter of the pair-produced colored parent particle
without ever having to consider missing energies less than 400 GeV.Comment: 26 pages, 8 Figures. Minor textual changes, typos fixed and
references adde
Wool sheep and purple snails - Longâterm continuity of animal exploitation in ancient Meninx (Jerba/Tunisia)
Archaeological research at the ancient city of Meninx in Jerba, Tunisia, carried out by the Institut National du Patrimoine Tunisie and Ludwig Maximilian University of Munich (LMU) produced more than 10,000 faunal specimens and shed light on subsistence activities spanning from the fourth century BCE until the seventh century CE. Despite its highly diverse fauna totalling at least 69 species of mammals, birds, reptiles, fish and molluscs, domestic livestock formed the mainstay of the economy at Meninx. Throughout site occupation and compared with contemporaneous sites in coastal Tunisia and Libya, sheep were of prime importance at Meninx. Diachronic demographic profiling illustrates an emphasis on the production of wool for making textiles. Together with the ubiquitous presence of crushed banded dyeâmurex (Hexaplex trunculus) shells implying exploitation of purple dyes, we assume that both activities were integrated into a single chaĂźne opĂ©ratoire for making purpleâdyed fabrics that were traded across the Mediterranean from Punic until Late Roman times. Zooarchaeological findings also suggest that during the Byzantine Period, this major economic activity came to a standstill, with people returning to more selfâsufficient subsistence strategies. An intersite comparison furthermore revealed that high proportions of ovicaprines are a typical feature of PunicâRoman sites in Jerba. But even at the height of Roman power in the region, autochthonous husbandry traditions continued to exist on the island, as illustrated by the fauna from Henchir Bourgou
Effect of a Brief Video Intervention on Incident Infection among Patients Attending Sexually Transmitted Disease Clinics
In a controlled trial at three urban STD clinics, Lee Warner and colleagues find that showing an educational video in waiting rooms reduced new infections by approximately 10%
Bacterial vaginosis
Bacterial vaginosis is the most prevalent cause of abnormal vaginal discharge in women of childbearing age. It can have a major impact on quality of life and psychological wellbeing if frequently recurrent and strongly symptomatic. The use of molecular techniques to study the vaginal microbiome is increasing our understanding of the dynamic changes in flora that occur in health and disease. It might soon be possible to separate Gardnerella into different pathogenic and non-pathogenic species. Many groups are studying compounds that can disrupt the biofilm which is dominated by Gardnerella and Atopobium vaginae. Several studies in the last decade support the concept of bacterial vaginosis as a sexually transmitted infection
Factors associated with non-attendance, opportunistic attendance and reminded attendance to cervical screening in an organized screening program: a cross-sectional study of 12,058 Norwegian women
<p>Abstract</p> <p>Background</p> <p>Cervical cancer incidence and mortality may be reduced by organized screening. Participant compliance with the attendance recommendations of the screening program is necessary to achieve this. Knowledge about the predictors of compliance is needed in order to enhance screening attendance.</p> <p>Methods</p> <p>The Norwegian Co-ordinated Cervical Cancer Screening Program (NCCSP) registers all cervix cytology diagnoses in Norway and individually reminds women who have no registered smear for the past three years to make an appointment for screening. In the present study, a questionnaire on lifestyle and health was administered to a random sample of Norwegian women. The response rate was 68%. To address the predictors of screening attendance for the 12,058 women aged 25-45 who were eligible for this study, individual questionnaire data was linked to the cytology registry of the NCCSP. We distinguished between non-attendees, opportunistic attendees and reminded attendees to screening for a period of four years. Predictors of non-attendance versus attendance and reminded versus opportunistic attendance were established by multivariate logistic regression.</p> <p>Results</p> <p>Women who attended screening were more likely than non-attendees to report that they were aware of the recommended screening interval, a history of sexually transmitted infections and a history of hormonal contraceptive and condom use. Attendance was also positively associated with being married/cohabiting, being a non-smoker and giving birth. Women who attended after being reminded were more likely than opportunistic attendees to be aware of cervical cancer and the recommended screening interval, but less likely to report a history of sexually transmitted infections and hormonal contraceptive use. Moreover, the likelihood of reminded attendance increased with age. Educational level did not significantly affect the women's attendance status in the fully adjusted models.</p> <p>Conclusions</p> <p>The likelihood of attendance in an organized screening program was higher among women who were aware of cervical screening, which suggests a potential for a higher attendance rate through improving the public knowledge of screening. Further, the lower awareness among opportunistic than reminded attendees suggests that physicians may inform their patients better when smears are taken at the physician's initiative.</p
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