745 research outputs found
Effect of methamphetamine dependence on inhibitory deficits in a novel human open-field paradigm.
RationaleMethamphetamine (MA) is an addictive psychostimulant associated with neurocognitive impairment, including inhibitory deficits characterized by a reduced ability to control responses to stimuli. While various domains of inhibition such as exaggerated novelty seeking and perseveration have been assessed in rodents by quantifying activity in open-field tests, similar models have not been utilized in human substance abusers. We recently developed a cross-species translational human open-field paradigm, the human behavior pattern monitor (hBPM), consisting of an unfamiliar room containing novel and engaging objects. Previous work demonstrated that manic bipolar subjects exhibit a disinhibited pattern of behavior in the hBPM characterized by increased object interactions.ObjectivesIn the current study, we examined the effect of MA dependence on inhibitory deficits using this paradigm. hBPM activity and object interactions were quantified in 16 abstinent MA-dependent individuals and 18 matched drug-free comparison subjects. The Wisconsin card sorting task (WCST) and the positive and negative syndrome scale (PANSS) were administered to assess executive function and psychopathology.ResultsMA-dependent participants exhibited a significant increase in total object interactions, time spent with objects, and perseverative object interactions relative to comparison subjects. Greater object interaction was associated with impaired performance on the WCST, higher PANSS scores, and more frequent MA use in the past year.ConclusionsAbstinent MA-dependent individuals exhibited impaired inhibition in the hBPM, displaying increased interaction with novel stimuli. Utilization of this measure may enable assessment of inhibitory deficits relevant to drug-seeking behavior and facilitate development of intervention methods to reduce high-risk conduct in this population
Physical exercise is associated with less neurocognitive impairment among HIV-infected adults
Abstract Neurocognitive impairment (NCI) remains prevalent in HIV infection. Randomized trials have shown that physical exercise improves NCI in non-HIV-infected adults, but data on HIV-infected populations are limited. Communitydwelling HIV-infected participants (n=335) completed a comprehensive neurocognitive battery that was utilized to define both global and domain-specific NCI. Participants were divided into "exercise" (n=83) and "no exercise" (n=252) groups based on whether they self-reported engaging in any activity that increased heart rate in the last 72 h or not. We also measured and evaluated a series of potential confounding factors, including demographics, HIV disease characteristics, substance use and psychiatric comorbidities, and physical functioning. Lower rates of global NCI were observed among the exercise group (15.7 %) as compared to those in the no exercise group (31.0 %; p<0.01). A multivariable logistic regression controlling for potential confounds (i.e., education, AIDS status, current CD4+ lymphocyte count, self-reported physical function, current depression) showed that being in the exercise group remained significantly associated with lower global NCI (odds ratio=2.63, p<0.05). Similar models of domain-specific NCI showed that exercise was associated with reduced impairment in working memory (p<0.05) and speed of information processing (p<0.05). The present findings suggest that HIVinfected adults who exercise are approximately half as likely to show NCI as compared to those who do not. Future longitudinal studies might be best suited to address causality, and intervention trials in HIV-infected individuals will determine whether exercise can prevent or ameliorate NCI in this population
Gas Accretion and Galactic Chemical Evolution: Theory and Observations
This chapter reviews how galactic inflows influence galaxy metallicity. The
goal is to discuss predictions from theoretical models, but particular emphasis
is placed on the insights that result from using models to interpret
observations. Even as the classical G-dwarf problem endures in the latest round
of observational confirmation, a rich and tantalizing new phenomenology of
relationships between , , SFR, and gas fraction is emerging both in
observations and in theoretical models. A consensus interpretation is emerging
in which star-forming galaxies do most of their growing in a quiescent way that
balances gas inflows and gas processing, and metal dilution with enrichment.
Models that explicitly invoke this idea via equilibrium conditions can be used
to infer inflow rates from observations, while models that do not assume
equilibrium growth tend to recover it self-consistently. Mergers are an overall
subdominant mechanism for delivering fresh gas to galaxies, but they trigger
radial flows of previously-accreted gas that flatten radial gas-phase
metallicity gradients and temporarily suppress central metallicities. Radial
gradients are generically expected to be steep at early times and then
flattened by mergers and enriched inflows of recycled gas at late times.
However, further theoretical work is required in order to understand how to
interpret observations. Likewise, more observational work is needed in order to
understand how metallicity gradients evolve to high redshifts.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
Springer. 29 pages, 2 figure
Lithic technological responses to Late Pleistocene glacial cycling at Pinnacle Point Site 5-6, South Africa
There are multiple hypotheses for human responses to glacial cycling in the Late Pleistocene, including changes in population size, interconnectedness, and mobility. Lithic technological analysis informs us of human responses to environmental change because lithic assemblage characteristics are a reflection of raw material transport, reduction, and discard behaviors that depend on hunter-gatherer social and economic decisions. Pinnacle Point Site 5-6 (PP5-6), Western Cape, South Africa is an ideal locality for examining the influence of glacial cycling on early modern human behaviors because it preserves a long sequence spanning marine isotope stages (MIS) 5, 4, and 3 and is associated with robust records of paleoenvironmental change. The analysis presented here addresses the question, what, if any, lithic assemblage traits at PP5-6 represent changing behavioral responses to the MIS 5-4-3 interglacial-glacial cycle? It statistically evaluates changes in 93 traits with no a priori assumptions about which traits may significantly associate with MIS. In contrast to other studies that claim that there is little relationship between broad-scale patterns of climate change and lithic technology, we identified the following characteristics that are associated with MIS 4: increased use of quartz, increased evidence for outcrop sources of quartzite and silcrete, increased evidence for earlier stages of reduction in silcrete, evidence for increased flaking efficiency in all raw material types, and changes in tool types and function for silcrete. Based on these results, we suggest that foragers responded to MIS 4 glacial environmental conditions at PP5-6 with increased population or group sizes, 'place provisioning', longer and/or more intense site occupations, and decreased residential mobility. Several other traits, including silcrete frequency, do not exhibit an association with MIS. Backed pieces, once they appear in the PP5-6 record during MIS 4, persist through MIS 3. Changing paleoenvironments explain some, but not all temporal technological variability at PP5-6.Social Science and Humanities Research Council of Canada; NORAM; American-Scandinavian Foundation; Fundacao para a Ciencia e Tecnologia [SFRH/BPD/73598/2010]; IGERT [DGE 0801634]; Hyde Family Foundations; Institute of Human Origins; National Science Foundation [BCS-9912465, BCS-0130713, BCS-0524087, BCS-1138073]; John Templeton Foundation to the Institute of Human Origins at Arizona State Universit
Repeated Assessment of Exploration and Novelty Seeking in the Human Behavioral Pattern Monitor in Bipolar Disorder Patients and Healthy Individuals
Exploration and novelty seeking are cross-species adaptive behaviors that are dysregulated in bipolar disorder (BD) and are critical features of the illness. While these behaviors have been extensively quantified in animals, multivariate human paradigms of exploration are lacking. The human Behavioral Pattern Monitor (hBPM), a human version of the animal open field, identified a signature pattern of hyper-exploration in manic BD patients, but whether exploratory behavior changes with treatment is unknown. The objective of this study was to assess the sensitivity of the hBPM to changes in manic symptoms, a necessary step towards elucidating the neurobiology underlying BD.Twelve acutely hospitalized manic BD subjects and 21 healthy volunteers were tested in the hBPM over three sessions; all subjects were retested one week after their first session and two weeks after their second session. Motor activity, spatial and entropic (degree of unpredictability) patterns of exploration, and interactions with novel objects were quantified. Manic BD patients demonstrated greater motor activity, extensive and more unpredictable patterns of exploration, and more object interactions than healthy volunteers during all three sessions. Exploration and novelty-seeking slightly decreased in manic BD subjects over the three sessions as their symptoms responded to treatment, but never to the level of healthy volunteers. Among healthy volunteers, exploration did not significantly decrease over time, and hBPM measures were highly correlated between sessions.Manic BD patients showed a modest reduction in symptoms yet still demonstrated hyper-exploration and novelty seeking in the hBPM, suggesting that these illness features may be enduring characteristics of BD. Furthermore, behavior in the hBPM is not subject to marked habituation effects. The hBPM can be reliably used in a repeated-measures design to characterize exploration and novelty seeking and, in parallel with animal studies, can contribute to developing treatments that target neuropsychiatric disease
Temporal Artery versus Bladder Thermometry during Adult Medical-Surgical Intensive Care Monitoring: An Observational Study
Abstract
Background
We sought to evaluate agreement between a new and widely implemented method of temperature measurement in critical care, temporal artery thermometry and an established method of core temperature measurement, bladder thermometry as performed in clinical practice.
Methods
Temperatures were simultaneously recorded hourly (n = 736 observations) using both devices as part of routine clinical monitoring in 14 critically ill adult patients with temperatures ranging ≥1°C prior to consent.
Results
The mean difference between temporal artery and bladder temperatures measured was -0.44°C (95% confidence interval, -0.47°C to -0.41°C), with temporal artery readings lower than bladder temperatures. Agreement between the two devices was greatest for normothermia (36.0°C to < 38.3°C) (mean difference -0.35°C [95% confidence interval, -0.37°C to -0.33°C]). The temporal artery thermometer recorded higher temperatures during hypothermia (< 36°C) (mean difference 0.66°C [95% confidence interval, 0.53°C to 0.79°C]) and lower temperatures during hyperthermia (≥38.3°C) (mean difference -0.90°C [95% confidence interval, -0.99°C to -0.81°C]). The sensitivity for detecting fever (core temperature ≥38.3°C) using the temporal artery thermometer was 0.26 (95% confidence interval, 0.20 to 0.33), and the specificity was 0.99 (95% confidence interval, 0.98 to 0.99). The positive likelihood ratio for fever was 24.6 (95% confidence interval, 10.7 to 56.8); the negative likelihood ratio was 0.75 (95% confidence interval, 0.68 to 0.82).
Conclusions
Temporal artery thermometry produces somewhat surprising disagreement with an established method of core temperature measurement and should not to be used in situations where body temperature needs to be measured with accuracy
Observation of two new baryon resonances
Two structures are observed close to the kinematic threshold in the mass spectrum in a sample of proton-proton collision data, corresponding
to an integrated luminosity of 3.0 fb recorded by the LHCb experiment.
In the quark model, two baryonic resonances with quark content are
expected in this mass region: the spin-parity and
states, denoted and .
Interpreting the structures as these resonances, we measure the mass
differences and the width of the heavier state to be
MeV,
MeV,
MeV, where the first and second
uncertainties are statistical and systematic, respectively. The width of the
lighter state is consistent with zero, and we place an upper limit of
MeV at 95% confidence level. Relative
production rates of these states are also reported.Comment: 17 pages, 2 figure
Constraints on the unitarity triangle angle from Dalitz plot analysis of decays
The first study is presented of CP violation with an amplitude analysis of
the Dalitz plot of decays, with , and . The analysis is based on a data sample corresponding to
of collisions collected with the LHCb detector. No
significant CP violation effect is seen, and constraints are placed on the
angle of the unitarity triangle formed from elements of the
Cabibbo-Kobayashi-Maskawa quark mixing matrix. Hadronic parameters associated
with the decay are determined for the first time. These
measurements can be used to improve the sensitivity to of existing and
future studies of the decay.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-059.html;
updated to correct figure 9 (numerical results unchanged
Study of and decays and determination of the CKM angle
We report a study of the suppressed and favored
decays, where the neutral meson is detected
through its decays to the and CP-even and
final states. The measurement is carried out using a proton-proton
collision data sample collected by the LHCb experiment, corresponding to an
integrated luminosity of 3.0~fb. We observe the first significant
signals in the CP-even final states of the meson for both the suppressed
and favored modes, as well as
in the doubly Cabibbo-suppressed final state of the decay. Evidence for the ADS suppressed decay , with , is also presented. From the observed
yields in the , and their
charge conjugate decay modes, we measure the value of the weak phase to be
. This is one of the most precise
single-measurement determinations of to date.Comment: 22 pages, 9 figures; All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-020.htm
Measurement of the mass and lifetime of the baryon
A proton-proton collision data sample, corresponding to an integrated
luminosity of 3 fb collected by LHCb at and 8 TeV, is used
to reconstruct , decays. Using the , decay mode for calibration, the lifetime ratio and absolute
lifetime of the baryon are measured to be \begin{align*}
\frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\
\tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the
uncertainties are statistical, systematic and from the calibration mode (for
only). A measurement is also made of the mass difference,
, and the corresponding mass, which
yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm
MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2.
\end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm
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