725 research outputs found
What is the excess risk of infertility in women after genital chlamydia infection? A systematic review of the evidence
Methods: Twelve databases were searched, limited to peer-reviewed literature published from January 1970 to September 2007. Conference abstracts and reference lists from reviews published since 2000 and from key articles were hand-searched. Studies were selected for review if they met the following criteria: (1) the study population comprised women of child-bearing age (defined as 15–45 years) and incorporated a comparison group of women documented as "chlamydia negative"; (2) the study outcomes included either infertility or successful pregnancy; and (3) the study design was one of the following: cohort, randomised controlled trial, "before and after" study, screening trial and systematic review. Studies were excluded if they described genital infections that either did not include Chlamydia trachomatis or described genital chlamydial co-infection, in which no data were available for C trachomatis infection alone.
Results: 3349 studies were identified by the search. One study satisfied the inclusion criteria, a longitudinal investigation measuring pregnancy rates in adolescent women with and without current chlamydial infection at baseline. That study reported no significant difference in subsequent pregnancy rates; however, it had serious methodological limitations, which restricted its conclusions.
Conclusions: This systematic review demonstrates the absence of valid evidence on the attributable risk of post-infective tubal factor infertility after genital chlamydial infection. The findings contribute empirical data to the growing debate surrounding previous assumptions about the natural history of chlamydial infection in women
Multisensory Processes: A Balancing Act across the Lifespan.
Multisensory processes are fundamental in scaffolding perception, cognition, learning, and behavior. How and when stimuli from different sensory modalities are integrated rather than treated as separate entities is poorly understood. We review how the relative reliance on stimulus characteristics versus learned associations dynamically shapes multisensory processes. We illustrate the dynamism in multisensory function across two timescales: one long term that operates across the lifespan and one short term that operates during the learning of new multisensory relations. In addition, we highlight the importance of task contingencies. We conclude that these highly dynamic multisensory processes, based on the relative weighting of stimulus characteristics and learned associations, provide both stability and flexibility to brain functions over a wide range of temporal scales
Causality in real-time dynamic substructure testing
Causality, in the bond graph sense, is shown to provide a conceptual framework for the design of real-time dynamic substructure testing experiments. In particular, known stability problems with split-inertia substructured systems are reinterpreted as causality issues within the new conceptual framework.
As an example, causality analysis is used to provide a practical solution to a split-inertia substructuring problem and the solution is experimentally verified
GLAST Large Area Telescope Multiwavelength Planning
Gamma-ray astrophysics depends in many ways on multiwavelength studies. The Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) Collaboration has started multiwavelength planning well before the scheduled 2007 launch of the observatory. Some of the high-priority multiwavelength needs include: (1) availability of contemporaneous radio and X-ray timing of pulsars; (2) expansion of blazar catalogs, including redshift measurements; (3) improved observations of molecular clouds, especially at high galactic latitudes; (4) simultaneous broad-spectrum blazar monitoring; (5) characterization of gamma-ray transients, including gamma ray bursts; (6) radio, optical, X-ray and TeV counterpart searches for reliable and effective sources identification and characterization. Several of these activities are needed to be in place before launch
Meditation-induced bliss viewed as release from conditioned neural (thought) patterns that block reward signals in the brain pleasure center
The nucleus accumbens orchestrates processes related to reward and pleasure,
including the addictive consequences of repeated reward (e.g., drug addiction and
compulsive gambling) and the accompanying feelings of craving and anhedonia.
The neurotransmitters dopamine and endogenous opiates play interactive roles in
these processes. They are released by natural rewards (i.e., food, water, sex, money,
play, etc.) and are released or mimicked by drugs of abuse. Repeated drug use
induces conditioned down-regulation of these neurotransmitters, thus causing
painful suppression of everyday pleasure. As with many spiritual traditions,
Buddhism provides strong advice against the pursuit of worldly pleasures to
attain the ‘‘good life.’’ In contrast, many forms of meditation give rise to an
immense and abiding joy. Most of these practices involve ‘‘stilling the mind,’’
whereby all content-laden thought (e.g., fantasies, daydreams, plans) ceases, and
the mind enters a state of openness, formlessness, clarity, and bliss. This can be
explained by the Buddhist suggestion that almost all of our everyday thoughts are
a form of addiction. It follows that if we turn off this internal ‘‘gossip of ego,’’ we
will find relief from the biochemical dopamine/opiate down-regulation, which is,
perhaps, the perpetual concomitant of our daily rumination
Edge states of graphene bilayer strip
The electronic structure of the zig-zag bilayer strip is analyzed. The
electronic spectra of the bilayer strip is computed. The dependence of the edge
state band flatness on the bilayer width is found. The density of states at the
Fermi level is analytically computed. It is shown that it has the singularity
which depends on the width of the bilayer strip. There is also asymmetry in the
density of states below and above the Fermi energy.Comment: 9 page
Complex differences in infection rates between ethnic groups in Scotland: a retrospective, national census-linked cohort study of 1.65 million cases
Background Ethnicity can influence susceptibility to infection, as COVID-19 has shown. Few countries have systematically investigated ethnic variations in infection. Methods We linked the Scotland 2001 Census, including ethnic group, to national databases of hospitalizations/deaths and serological diagnoses of bloodborne viruses for 2001–2013. We calculated age-adjusted rate ratios (RRs) in 12 ethnic groups for all infections combined, 15 infection categories, and human immunodeficiency virus (HIV), hepatitis B (HBV) and hepatitis C (HCV) viruses. Results We analysed over 1.65 million infection-related hospitalisations/deaths. Compared with White Scottish, RRs for all infections combined were 0.8 or lower for Other White British, Other White and Chinese males and females, and 1.2–1.4 for Pakistani and African males and females. Adjustment for socioeconomic status or birthplace had little effect. RRs for specific infection categories followed similar patterns with striking exceptions. For HIV, RRs were 136 in African females and 14 in males; for HBV, 125 in Chinese females and 59 in males, 55 in African females and 24 in males; and for HCV, 2.3–3.1 in Pakistanis and Africans. Conclusions Ethnic differences were found in overall rates and many infection categories, suggesting multiple causative pathways. We recommend census linkage as a powerful method for studying the disproportionate impact of COVID-19
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