575 research outputs found
Coherent Multidecadal Atmospheric and Oceanic Variability in the North Atlantic: Blocking Corresponds with Warm Subpolar Ocean
Winters with frequent atmospheric blocking, in a band of latitudes from Greenland to Western Europe, are found to persist over several decades and correspond to a warm North Atlantic Ocean. This is evident in atmospheric reanalysis data, both modern and for the full 20th century. Blocking is approximately in phase with Atlantic multidecadal ocean variability (AMV). Wintertime atmospheric blocking involves a highly distorted jetstream, isolating large regions of air from the westerly circulation. It influences the ocean through windstress-curl and associated air/sea heat flux. While blocking is a relatively high-frequency phenomenon, it is strongly modulated over decadal timescales. The blocked regime (weaker ocean gyres, weaker air-sea heat flux, paradoxically increased transport of warm subtropical waters poleward) contributes to the warm phase of AMV. Atmospheric blocking better describes the early 20thC warming and 1996-2010 warm period than does the NAO index. It has roots in the hemispheric circulation and jet stream dynamics. Subpolar Atlantic variability covaries with distant AMOC fields: both these connections may express the global influence of the subpolar North Atlantic ocean on the global climate system
Observations of Recent Arctic Sea Ice Volume Loss and Its Impact on Ocean-Atmosphere Energy Exchange and Ice Production
Using recently developed techniques we estimate snow and sea ice thickness distributions for the Arctic basin through the combination of freeboard data from the Ice, Cloud, and land Elevation Satellite (ICESat) and a snow depth model. These data are used with meteorological data and a thermodynamic sea ice model to calculate ocean-atmosphere heat exchange and ice volume production during the 2003-2008 fall and winter seasons. The calculated heat fluxes and ice growth rates are in agreement with previous observations over multiyear ice. In this study, we calculate heat fluxes and ice growth rates for the full distribution of ice thicknesses covering the Arctic basin and determine the impact of ice thickness change on the calculated values. Thinning of the sea ice is observed which greatly increases the 2005-2007 fall period ocean-atmosphere heat fluxes compared to those observed in 2003. Although there was also a decline in sea ice thickness for the winter periods, the winter time heat flux was found to be less impacted by the observed changes in ice thickness. A large increase in the net Arctic ocean-atmosphere heat output is also observed in the fall periods due to changes in the areal coverage of sea ice. The anomalously low sea ice coverage in 2007 led to a net ocean-atmosphere heat output approximately 3 times greater than was observed in previous years and suggests that sea ice losses are now playing a role in increasing surface air temperatures in the Arctic
Gamma oscillatory amplitude encodes stimulus intensity in primary somatosensory cortex
Gamma oscillations have previously been linked to pain perception and it has been hypothesised that they may have a potential role in encoding pain intensity. Stimulus response experiments have reported an increase in activity in the primary somatosensory cortex (SI) with increasing stimulus intensity, but the specific role of oscillatory dynamics in this change in activation remains unclear. In this study, Magnetoencephalography (MEG) was used to investigate the changes in cortical oscillations during 4 different intensities of a train of electrical stimuli to the right index finger, ranging from low sensation to strong pain. In those participants showing changes in evoked oscillatory gamma in SI during stimulation, the strength of the gamma power was found to increase with increasing stimulus intensity at both pain and sub-pain thresholds. These results suggest that evoked gamma oscillations in SI are not specific to pain but may have a role in encoding somatosensory stimulus intensity. © 2013 Rossiter, Worthen, Witton, Hall and Furlong
The Use of a Large, Extensive Green Roof for Multiple Research Objectives
The Green Roof on the Onondaga County Convention Center in Syracuse, NY is planted with several varieties of sedum over an area of 0.56 hectares. The roof was constructed in 2011, and has been instrumented with sensors to enable research and education over an extended period. The purpose of the current work on this roof is to quantify its performance with respect to water storage and energy transfer, and to identify chemical constituents in the runoff that might be contributed by the growth medium. The scope of the project also includes a number of measurements on traditional roofs in the vicinity of the Convention Center as controls. Experimental methods include measurements with temperature probes installed in different layers of the green roof, a meteorological station, soil moisture sensors positioned around the roof, and an electromagnetic flowmeter connected to the roof drains. Chemical analysis of incoming precipitation and stormwater runoff is conducted by ion chromatography. Besides the research underway, an educational website is under construction that shows realtime data from many of the instruments. The website includes explanations of the energy flow through the roof layers, water flow and water storage in the growth medium, and runoff through the roof drains. The website is designed for use by teachers of K-12 and undergraduate courses to enable students to learn about green roofs as a tool for managing urban stormwater. Results of the research show that heat flow through the roof is largely controlled by extruded polystyrene insulation below the growth medium, and that the growth medium is not a major barrier to heat flow. Substantial amounts of stormwater can be stored by the roof, as long as the growth medium is able to dry somewhat between storms. Precipitation events in close succession may cause the growth medium to stay saturated, preventing the roof from storing additional stormwater. The results of this work are important for assisting designers and engineers to improve the performance of green roofs
An evaluation of Bradfordizing effects
The purpose of this paper is to apply and evaluate the bibliometric method Bradfordizing for information retrieval (IR) experiments. Bradfordizing is used for generating core document sets for subject-specific questions and to reorder result sets from distributed searches. The method will be applied and tested in a controlled scenario of scientific literature databases from social and political sciences, economics, psychology and medical science (SOLIS, SoLit, USB Köln Opac, CSA Sociological Abstracts, World Affairs Online, Psyndex and Medline) and 164 standardized topics. An evaluation of the method and its effects is carried out in two laboratory-based information retrieval experiments (CLEF and KoMoHe) using a controlled document corpus and human relevance assessments. The results show that Bradfordizing is a very robust method for re-ranking the main document types (journal articles and monographs) in today’s digital libraries (DL). The IR tests show that relevance distributions after re-ranking improve at a significant level if articles in the core are compared with articles in the succeeding zones. The items in the core are significantly more often assessed as relevant, than items in zone 2 (z2) or zone 3 (z3). The improvements between the zones are statistically significant based on the Wilcoxon signed-rank test and the paired T-Test
The Role of Phytoplankton Dynamics in the Seasonal and Interannual Variability of Carbon in the Subpolar North Atlantic - a Modeling Study
We developed an ecosystem/biogeochemical model system, which includes multiple phytoplankton functional groups and carbon cycle dynamics, and applied it to investigate physical-biological interactions in Icelandic waters. Satellite and in situ data were used to evaluate the model. Surface seasonal cycle amplitudes and biases of key parameters (DIC, TA, pCO2, air-sea CO2 flux, and nutrients) are significantly improved when compared to surface observations by prescribing deep water values and trends, based on available data. The seasonality of the coccolithophore and "other phytoplankton" (diatoms and dinoflagellates) blooms is in general agreement with satellite ocean color products. Nutrient supply, biomass and calcite concentrations are modulated by light and mixed layer depth seasonal cycles. Diatoms are the most abundant phytoplankton, with a large bloom in early spring and a secondary bloom in fall. The diatom bloom is followed by blooms of dinoflagellates and coccolithophores. The effect of biological changes on the seasonal variability of the surface ocean pCO2 is nearly twice the temperature effect, in agreement with previous studies. The inclusion of multiple phytoplankton functional groups in the model played a major role in the accurate representation of CO2 uptake by biology. For instance, at the peak of the bloom, the exclusion of coccolithophores causes an increase in alkalinity of up to 4 mol kg(sup 1) with a corresponding increase in DIC of up to 16 mol kg(sup 1). During the peak of the bloom in summer, the net effect of the absence of the coccolithophores bloom is an increase in pCO2 of more than 20 atm and a reduction of atmospheric CO2 uptake of more than 6 mmolm(sup 2) d(sup 1). On average, the impact of coccolithophores is an increase of air-sea CO2 flux of about 27 %. Considering the areal extent of the bloom from satellite images within the Irminger and Icelandic Basins, this reduction translates into an annual mean of nearly 1500 tonnes C yr(sup 1)
Sex Disparities in Arrest Outcomes for Domestic Violence
Domestic violence arrests have been historically focused on protecting women and children from abusive men. Arrest patterns continue to reflect this bias with more men arrested for domestic violence compared to women. Such potential gender variations in arrest patterns pave the way to the investigation of disparities by sex of the offender in domestic violence arrests. This study utilizes data from a quantitative dataset that includes responses by police officers who completed a specially mandated checklist after responding to a domestic dispute. The results showed that while females are arrested quite often in domestic disputes, there remains a significant difference in the arrest outcome whereby male suspects were more likely to be arrested than female suspects. Regression models further indicated differences based on sex and certain predictors of arrest, which supported sex-based rationales in arrests for domestic violence.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
Social Interactions vs Revisions, What is important for Promotion in Wikipedia?
In epistemic community, people are said to be selected on their knowledge
contribution to the project (articles, codes, etc.) However, the socialization
process is an important factor for inclusion, sustainability as a contributor,
and promotion. Finally, what does matter to be promoted? being a good
contributor? being a good animator? knowing the boss? We explore this question
looking at the process of election for administrator in the English Wikipedia
community. We modeled the candidates according to their revisions and/or social
attributes. These attributes are used to construct a predictive model of
promotion success, based on the candidates's past behavior, computed thanks to
a random forest algorithm.
Our model combining knowledge contribution variables and social networking
variables successfully explain 78% of the results which is better than the
former models. It also helps to refine the criterion for election. If the
number of knowledge contributions is the most important element, social
interactions come close second to explain the election. But being connected
with the future peers (the admins) can make the difference between success and
failure, making this epistemic community a very social community too
Anger problems and posttraumatic stress disorder in male and female National Guard and Reserve Service members
Anger is a common problem among veterans and has been associated with posttraumatic stress disorder (PTSD). This study aimed to improve understanding of how anger and PTSD co-occur by examining gender differences and differences by whether the triggering traumatic event is deployment-related vs. civilian-related in current service members. A representative cohort of Reserve and National Guard service personnel (n = 1293) were interviewed to assess for deployment- or civilian-related traumas, PTSD, and anger. The prevalence of self-reported anger problems was estimated among male (n = 1036) and female (n = 257) service members. Log Poisson regression models with robust standard errors were used to estimate the associations of problems with anger with PTSD and PTSD symptom severity for men and women. Self-reported anger problems were common among male (53.0%) and female (51.3%) service members. Adjusted prevalence ratios (PR) showed associations between anger and PTSD connected to both civilian- and deployment-related traumas (PR were 1.77 (95% CI 1.52–2.05) and 1.85 (95% CI 1.62–2.12), respectively). PTSD symptom severity was also associated with anger. This study was cross-sectional and so a causal relationship between PTSD and anger cannot be established. Problems with anger are common among male and female current Guard and Reserve members. These findings suggest that anger treatment should be made available to current service members and that clinicians should assess anger problems irrespective of gender. Future research should examine the effectiveness of anger treatment protocols by gender
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