661 research outputs found
Investigating the Causal Mechanisms of Symptom Recovery in Chronic Whiplash-associated Disorders Using Bayesian Networks
Objectives: The present study’s objective was to understand the causal mechanisms underpinning the recovery of individuals with whiplash-associated disorders (WAD). We applied Bayesian Networks (BN) to answer 2 study aims: (1) to identify the causal mechanism(s) of recovery underpinning neck-specific exercise (NSE), and (2) quantify if the cyclical pathway of the fear-avoidance model (FAM) is supported by the present data.
Materials and Methods: We analyzed a prospective cohort data set of 216 individuals with chronic WAD. Fifteen variables were used to build a BN model: treatment group (NSE with or without a behavioral approach, or general physical activity), muscle endurance, range of motion, hand strength, neck proprioception, pain catastrophizing, fear, anxiety, depression, self-efficacy, perceived work ability, disability, pain intensity, sex, and follow-up time.
Results: The BN model showed that neck pain reduction rate was greater after NSE compared with physical activity prescription (β=0.59 points per month [P<0.001]) only in the presence of 2 mediators: global neck muscle endurance and perceived work ability. We also found the following pathway of variables that constituted the FAM: anxiety, followed by depressive symptoms, fear, catastrophizing, self-efficacy, and consequently pain.
Conclusions: e uncovered 2 mediators that explained the mechanisms of effect behind NSE, and proposed an alternative FAM pathway. The present study is the first to apply BN modelling to understand the causal mechanisms of recovery in WAD. In doing so, it is anticipated that such analytical methods could increase the precision of treatment of individuals with chronic WAD
The risk of menstrual abnormalities after tubal sterilization: a case control study
BACKGROUND: Tubal sterilization is the method of family planning most commonly used. The existence of the post-tubal-ligation syndrome of menstrual abnormalities has been the subject of debate for decades. METHODS: In a cross-sectional study, 112 women with the history of Pomeroy type of tubal ligation achieved by minilaparatomy as the case group and 288 women with no previous tubal ligation as the control group were assessed for menstrual abnormalities. RESULTS: Menstrual abnormalities were not significantly different between the case and control groups (p = 0.824). The abnormal uterine bleeding frequency differences in two different age groups (30–39 and 40–45 years old) were statistically significant (p = 0.0176). CONCLUSION: Tubal sterilization does not cause menstrual irregularities
First Order Quark-Gluon/Hadron Transition May Affect Cosmological Nucleosynthesis
In the model of a first order quark-gluon/hadron phase transition in which
the hadronic phase is considered as vacuum bubbles growing in the quark-gluon
background with chiral symmetry broken inside the bubble, we find the estimate
for the length scale associated with inhomogeneities originated during the
transition, m m, being
sufficient to produce significant effects on cosmological nucleosynthesis.Comment: 10 pages, LaTeX, to appear in Phys. Lett. B, 199
Mid-Infrared Properties of the Swift Burst Alert Telescope Active Galactic Nuclei Sample of the Local Universe. I. Emission-Line Diagnostics
We compare mid-infrared emission-line properties, from high-resolution
Spitzer spectra of a hard X-ray (14 -- 195 keV) selected sample of nearby (z <
0.05) AGN detected by the Burst Alert Telescope (BAT) aboard Swift. The
luminosity distribution for the mid-infrared emission-lines, [O IV] 25.89
micron, [Ne II] 12.81 micron, [Ne III] 15.56 micron and [Ne V] 14.32/24.32
micron, and hard X-ray continuum show no differences between Seyfert 1 and
Seyfert 2 populations, however six newly discovered BAT AGNs are under-luminous
in [O IV], most likely the result of dust extinction in the host galaxy. The
overall tightness of the mid-infrared correlations and BAT fluxes and
luminosities suggests that the emission lines primarily arise in gas ionized by
the AGN. We also compare the mid-infrared emission-lines in the BAT AGNs with
those from published studies of ULIRGs, PG QSOs, star-forming galaxies and
LINERs. We find that the BAT AGN sample fall into a distinctive region when
comparing the [Ne III]/[Ne II] and the [O IV]/[Ne III] ratios. These line
ratios are lower in sources that have been previously classified in the
mid-infrared/optical as AGN than those found for the BAT AGN, suggesting that,
in our X-ray selected sample, the AGN represents the main contribution to the
observed line emission. These ratios represent a new emission line diagnostic
for distinguishing between AGN and star forming galaxies.Comment: 54 pages, 9 Figures. Accepted for publication in The Astrophysical
Journal
Unanswered ethical and scientific questions for trials of invasive interventions for coronary disease: The case of single vessel disease
Trials in the 1990s demonstrated that medical therapy is as effective as invasive therapies for treating single-vessel coronary disease. Yet more recent studies enrolling patients with this condition have focused on evaluating only invasive approaches, namely, stenting versus coronary artery bypass surgery. Several ethical and scientific questions remain unanswered regarding the conduct of these later trials. Were they justified? Why wasn't a medical therapy arm included? Were subjects informed about the availability of medical therapy as an equivalent option? Was optimized medical therapy given prior to randomization? The absence of clear answers to these questions raises the possibility of serious bias in favor of invasive interventions. Considering that medical therapy is underutilized in patients with coronary disease, efforts should focus more on increasing utilization of medical therapy and proper selection of noninvasive interventions
Induced pseudoscalar coupling of the proton weak interaction
The induced pseudoscalar coupling is the least well known of the weak
coupling constants of the proton's charged--current interaction. Its size is
dictated by chiral symmetry arguments, and its measurement represents an
important test of quantum chromodynamics at low energies. During the past
decade a large body of new data relevant to the coupling has been
accumulated. This data includes measurements of radiative and non radiative
muon capture on targets ranging from hydrogen and few--nucleon systems to
complex nuclei. Herein the authors review the theoretical underpinnings of
, the experimental studies of , and the procedures and uncertainties
in extracting the coupling from data. Current puzzles are highlighted and
future opportunities are discussed.Comment: 58 pages, Latex, Revtex4, prepared for Reviews of Modern Physic
A Generalized Fluctuation-Dissipation Theorem for Nonlinear Response Functions
A nonlinear generalization of the Fluctuation-Dissipation Theorem (FDT) for
the n-point Green functions and the amputated 1PI vertex functions at finite
temperature is derived in the framework of the Closed Time Path formalism. We
verify that this generalized FDT coincides with known results for n=2 and 3.
New explicit relations among the 4-point nonlinear response and correlation
(fluctuation) functions are presented.Comment: 34 pages, Revte
Internet-based medical education: a realist review of what works, for whom and in what circumstances
http://creativecommons.org/licenses/by/2.0
Rem2-Targeted shRNAs Reduce Frequency of Miniature Excitatory Postsynaptic Currents without Altering Voltage-Gated Ca2+ Currents
Ca2+ influx through voltage-gated Ca2+ channels (VGCCs) plays important roles in neuronal cell development and function. Rem2 is a member of the RGK (Rad, Rem, Rem2, Gem/Kir) subfamily of small GTPases that confers potent inhibition upon VGCCs. The physiologic roles of RGK proteins, particularly in the brain, are poorly understood. Rem2 was implicated in synaptogenesis through an RNAi screen and proposed to regulate Ca2+ homeostasis in neurons. To test this hypothesis and uncover physiological roles for Rem2 in the brain, we investigated the molecular mechanisms by which Rem2 knockdown affected synaptogenesis and Ca2+ homeostasis in cultured rat hippocampal neurons. Expression of a cocktail of shRNAs targeting rat Rem2 (rRem2) reduced the frequency of miniature excitatory postsynaptic currents (mEPSCs) measured 10 d after transfection (14 d in vitro), but did not affect mEPSC amplitude. VGCC current amplitude after rRem2-targeted knockdown was not different from that in control cells, however, at either 4 or 10 d post transfection. Co-expression of a human Rem2 that was insensitive to the shRNAs targeting rRem2 was unable to prevent the reduction in mEPSC frequency after rRem2-targeted knockdown. Over-expression of rRem2 resulted in 50% reduction in VGCC current, but neither the mEPSC frequency nor amplitude was affected. Taken together, the observed effects upon synaptogenesis after shRNA treatment are more likely due to mechanisms other than modulation of VGCCs and Ca2+ homeostasis, and may be independent of Rem2. In addition, our results reveal a surprising lack of contribution of VGCCs to synaptogenesis during early development in cultured hippocampal neurons
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