1,415 research outputs found
The role of dopamine in the accumbens core in the expression of Pavlovianâconditioned responses
The role of dopamine in reward is a topic of debate. For example, some have argued that phasic dopamine signaling provides a predictionâerror signal necessary for stimulusâreward learning, whereas others have hypothesized that dopamine is not necessary for learning per se , but for attributing incentive motivational value (âincentive salienceâ) to reward cues. These psychological processes are difficult to tease apart, because they tend to change together. To disentangle them we took advantage of natural individual variation in the extent to which reward cues are attributed with incentive salience, and asked whether dopamine (specifically in the core of the nucleus accumbens) is necessary for the expression of two forms of Pavlovianâconditioned approach behavior â one in which the cue acquires powerful motivational properties (signâtracking) and another closely related one in which it does not (goalâtracking). After acquisition of these conditioned responses (CRs), intraâaccumbens injection of the dopamine receptor antagonist flupenthixol markedly impaired the expression of a signâtracking CR, but not a goalâtracking CR. Furthermore, dopamine antagonism did not produce a gradual extinctionâlike decline in behavior, but maximally impaired expression of a signâtracking CR on the very first trial, indicating the effect was not due to new learning (i.e. it occurred in the absence of new predictionâerror computations). The data support the view that dopamine in the accumbens core is not necessary for learning stimulusâreward associations, but for attributing incentive salience to reward cues, transforming predictive conditional stimuli into incentive stimuli with powerful motivational properties. Ongoing debate exists about dopamineâs exact role in rewardârelated processes. We took advantage of natural individual variation in the degree to which reward cues are attributed with motivational value, and asked whether dopamine in the core of the nucleus accumbens is necessary for the performance of two forms of Pavlovian conditioned approach behavior â one in which the cue acquires powerful motivational properties (signâtracking) and another related one in which it does not (goalâtracking). We found that blocking dopamine transmission within the core impaired the expression of signâtracking responses, but not goalâtracking responses.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93510/1/j.1460-9568.2012.08217.x.pd
Web-Based Training for an Evidence-Supported Treatment: Training Completion and Knowledge Acquisition in a Global Sample of Learners
The purpose of this investigation is to describe the characteristics of professional and preprofessional learners who registered for and completed TF-CBTWeb, a modular, web-based training program designed to promote the dissemination of Trauma-Focused Cognitive Behavioral Therapy (TF-CBT) and to demonstrate the feasibility of this method of dissemination. Between October 1, 2005, and October 1, 2012, a total of 123,848 learners registered for TF-CBTWeb, of whom 98,646 (79.7%) initiated the learning activities by beginning the first module pretest. Of those, 67,201 (68.1%) completed the full training. Registrants hailed from 130 countries worldwide, and they had varied educational backgrounds, professional identities (both professional and preprofessional), and a range of experience working with child trauma victims. Learners who were from the United States, students, those with masterâs degrees, and those with fewer years of experience working with child trauma victims tended to have the highest course completion rates. Learners displayed significant increases in knowledge about each component of TF-CBT, based on module pretest and posttest scores. The advantages and limitations of this web-based training program evaluation are discussed, while important implications for the use of web-based trainings are reviewed
Raman Quantum Memory with Built-In Suppression of Four-wave Mixing Noise
Quantum memories are essential for large-scale quantum information networks.
Along with high efficiency, storage lifetime and optical bandwidth, it is
critical that the memory add negligible noise to the recalled signal. A common
source of noise in optical quantum memories is spontaneous four-wave mixing. We
develop and implement a technically simple scheme to suppress this noise
mechanism by means of quantum interference. Using this scheme with a Raman
memory in warm atomic vapour we demonstrate over an order of magnitude
improvement in noise performance. Furthermore we demonstrate a method to
quantify the remaining noise contributions and present a route to enable
further noise suppression. Our scheme opens the way to quantum demonstrations
using a broadband memory, significantly advancing the search for scalable
quantum photonic networks.Comment: 6 pages, 5 figures plus Supplementary Materia
eleanor: An open-source tool for extracting light curves from the TESS Full-Frame Images
During its two year prime mission the Transiting Exoplanet Survey Satellite
(TESS) will perform a time-series photometric survey covering over 80% of the
sky. This survey comprises observations of 26 24 x 96 degree sectors that are
each monitored continuously for approximately 27 days. The main goal of TESS is
to find transiting planets around 200,000 pre-selected stars for which fixed
aperture photometry is recorded every two minutes. However, TESS is also
recording and delivering Full-Frame Images (FFIs) of each detector at a 30
minute cadence. We have created an open-source tool, eleanor, to produce light
curves for objects in the TESS FFIs. Here, we describe the methods used in
eleanor to produce light curves that are optimized for planet searches. The
tool performs background subtraction, aperture and PSF photometry,
decorrelation of instrument systematics, and cotrending using principal
component analysis. We recover known transiting exoplanets in the FFIs to
validate the pipeline and perform a limited search for new planet candidates in
Sector 1. Our tests indicate that eleanor produces light curves with
significantly less scatter than other tools that have been used in the
literature. Cadence-stacked images, and raw and detrended eleanor light curves
for each analyzed star will be hosted on MAST, with planet candidates on
ExoFOP-TESS as Community TESS Objects of Interest (CTOIs). This work confirms
the promise that the TESS FFIs will enable the detection of thousands of new
exoplanets and a broad range of time domain astrophysics.Comment: 21 pages, 13 figures, 2 tables, Accepted to PAS
Fragile antiferromagnetism in the heavy-fermion compound YbBiPt
We report results from neutron scattering experiments on single crystals of
YbBiPt that demonstrate antiferromagnetic order characterized by a propagation
vector, = (), and
ordered moments that align along the [1 1 1] direction of the cubic unit cell.
We describe the scattering in terms of a two-Gaussian peak fit, which consists
of a narrower component that appears below K and
corresponds to a magnetic correlation length of 80
, and a broad component that persists up to 0.7 K and
corresponds to antiferromagnetic correlations extending over 20 . Our results illustrate the fragile magnetic order
present in YbBiPt and provide a path forward for microscopic investigations of
the ground states and fluctuations associated with the purported quantum
critical point in this heavy-fermion compound.Comment: 5 pages, 3 figure
Relations Among Gender, Violence Exposure, and Mental Health: The National Survey of Adolescents
Using a nationally representative sample of 4,008 adolescents, this study examines gender differences in violence exposure, major depressive episode (MDE) and posttraumatic stress disorder (PTSD), and characteristics of violence incidents. It was hypothesized that there would be gender differences in the types of violence exposure reported as well as the prevalence of MDE and PTSD; and that gender would moderate the relationship between violence exposure and mental health outcomes. Results indicated significant gender differences in rates of violence exposure, PTSD and MDE. Additionally, gender was a moderating variable in the relation between sexual assault and PTSD, but not in the other violence exposure-mental health relations examined. It thus appears that the pathways for developing PTSD may be different for male and female victims of sexual abuse. Implications for interventions and future research are discussed
Taxometric Investigation of PTSD: Data From Two Nationally Representative Samples
Current psychiatric nosology depicts posttraumatic stress disorder (PTSD) as a discrete diagnostic category. However, only one study has examined the latent structure of PTSD, and this study suggested that PTSD may be more accurately conceptualized as an extreme reaction to traumatic life events rather than a discrete clinical syndrome. To build on the existing literature base, the present research examined the latent structure of posttraumatic stress reactions by applying three taxometric procedures (MAXEIG, MAMBAC, and L-Mode) to data collected from large nationally representative samples of women (ns = 2684 and 3033) and adolescents (n = 3775). Results consistently provided evidence for a dimensional PTSD solution across samples and statistical procedures. These findings have important implications for the theory, assessment, and investigation of posttraumatic stress reactions
Drivers of global mangrove loss and gain in social-ecological systems
Mangrove forests store high amounts of carbon, protect communities from storms, and support fisheries. Mangroves exist in complex social-ecological systems, hence identifying socioeconomic conditions associated with decreasing losses and increasing gains remains challenging albeit important. The impact of national governance and conservation policies on mangrove conservation at the landscape-scale has not been assessed to date, nor have the interactions with local economic pressures and biophysical drivers. Here, we assess the relationship between socioeconomic and biophysical variables and mangrove change across coastal geomorphic units worldwide from 1996 to 2016. Globally, we find that drivers of loss can also be drivers of gain, and that drivers have changed over 20 years. The association with economic growth appears to have reversed, shifting from negatively impacting mangroves in the first decade to enabling mangrove expansion in the second decade. Importantly, we find that community forestry is promoting mangrove expansion, whereas conversion to agriculture and aquaculture, often occurring in protected areas, results in high loss. Sustainable development, community forestry, and co-management of protected areas are promising strategies to reverse mangrove losses, increasing the capacity of mangroves to support human-livelihoods and combat climate change
Who Will Volunteer? Religiosity, Everyday Racism, and Social Participation Among African American Men
This study explores the relative importance of everyday racism, empathic concern, communalism, and religiosity as predictors of pro-social involvement (i.e., volunteerism and membership in political/social justice organizations) among a sample of African American men ( N = 151). Church involvement emerged as a positive predictor of the likelihood that these men were involved in volunteer work as well as the number of hours that men dedicated to volunteer work. Communalism positively predicted the amount of time (in hours per year) that men were involved in volunteer work. Subjective religiosity and the stress of everyday racism were associated with a greater likelihood of being a member of a politicalâsocial justice organization. Implications of these findings are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44632/1/10804_2004_Article_496119.pd
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