3,570 research outputs found
The Energy Conserving Particle-in-Cell Method
A new Particle-in-Cell (PIC) method, that conserves energy exactly, is
presented. The particle equations of motion and the Maxwell's equations are
differenced implicitly in time by the midpoint rule and solved concurrently by
a Jacobian-free Newton Krylov (JFNK) solver. Several tests show that the finite
grid instability is eliminated in energy conserving PIC simulations, and the
method correctly describes the two-stream and Weibel instabilities, conserving
exactly the total energy. The computational time of the energy conserving PIC
method increases linearly with the number of particles, and it is rather
insensitive to the number of grid points and time step. The kinetic enslavement
technique can be effectively used to reduce the problem matrix size and the
number of JFNK solver iterations
Discrepant Alcohol Use, Intimate Partner Violence, and Relationship Adjustment Among Lesbian Women and Their Same-Sex Intimate Partners
This study examined the association between relationship adjustment and discrepant alcohol use among lesbian women and their same-sex intimate partners after controlling for verbal and physical aggression. Lesbian women (N = 819) who were members of online marketing research panels completed an online survey in which they reported both their own and same-sex intimate partner\u27s alcohol use, their relationship adjustment, and their own and their partner\u27s physical aggression and psychological aggression (i.e., verbal aggression and dominance/isolation). Partners\u27 alcohol use was moderately correlated. Discrepancy in alcohol use was associated with poorer relationship adjustment after controlling for psychological aggression and physical aggression. Results are discussed in terms of the similarity and differences with previous literature primarily focused on heterosexual couples
Water vapour source impacts on oxygen isotope variability in tropical precipitation during Heinrich events
Water isotope records such as speleothems provide extensive evidence of past tropical hydrological changes. During Heinrich events, isotopic changes in monsoon regions have been interpreted as implying a widespread drying through the Northern Hemisphere tropics and an anti-phased precipitation response in the south. Here, we examine the sources of this variability using a water isotope-enabled general circulation model, Goddard Institute for Space Studies ModelE. We incorporate a new suite of vapour source distribution tracers to help constrain the impact of precipitation source region changes on the isotopic composition of precipitation and to identify nonlocal amount effects. We simulate a collapse of the North Atlantic meridional overturning circulation with a large freshwater input to the region as an idealised analogue to iceberg discharge during Heinrich events. An increase in monsoon intensity, defined by vertical wind shear, is modelled over the South American domain, with small decreases simulated over Asia. Simulated isotopic anomalies agree well with proxy climate records, with lighter isotopic values simulated over South America and enriched values across East Asia. For this particular abrupt climate event, we identify which climatic change is most likely linked to water isotope change – changes in local precipitation amount, monsoon intensity, water vapour source distributions or precipitation seasonality. We categorise individual sites according to the climate variability that water isotope changes are most closely associated with, and find that the dominant isotopic controls are not consistent across the tropics – simple local explanations, in particular, fall short of explaining water isotope variability at all sites. Instead, the best interpretations appear to be site specific and often regional in scale
Empirical Investigation of a Model of Sexual Minority Specific and General Risk Factors for Intimate Partner Violence Among Lesbian Women
Objective: This study proposed and tested the first conceptual model of sexual minority specific (discrimination, internalized homophobia) and more general risk factors (perpetrator and partner alcohol use, anger, relationship satisfaction) for intimate partner violence among partnered lesbian women.
Method: Selfidentified lesbian women (N = 1,048) were recruited from online market research panels. Participants completed an online survey that included measures of minority stress, anger, alcohol use and alcohol-related problems, relationship satisfaction, psychological aggression, and physical violence.
Results: The model demonstrated good fit and significant links from sexual minority discrimination to internalized homophobia and anger, from internalized homophobia to anger and alcohol problems, and from alcohol problems to intimate partner violence. Partner alcohol use predicted partner physical violence. Relationship dissatisfaction was associated with physical violence via psychological aggression. Physical violence was bidirectional.
Conclusions: Minority stress, anger, alcohol use, and alcohol-related problems play an important role in perpetration of psychological aggression and physical violence in lesbian women\u27s intimate partner relationships. The results of this study provide evidence of potentially modifiable sexual minority specific and more general risk factors for lesbian women\u27s partner violence
Comparison of Forced ENSO-Like Hydrological Expressions in Simulations of the Preindustrial and Mid-Holocene
Using the water isotope- and vapor source distribution (VSD) tracer-enabled Goddard Institute for Space Studies ModelE-R, we examine changing El Nino-Southern Oscillation (ENSO)-like expressions in the hydrological cycle in a suite of model experiments. We apply strong surface temperature anomalies associated with composite observed El Nino and La Nina events as surface boundary conditions to preindustrial and mid-Holocene model experiments in order to investigate ENSO-like expressions in the hydrological cycle under varying boundary conditions. We find distinct simulated hydrological anomalies associated with El Nino-like ("ENSOWARM") and La Nina-like ("ENSOCOOL") conditions, and the region-specific VSD tracers show hydrological differences across the Pacific basin between El Nino-like and La Nina-like events. The application of ENSOCOOL forcings does not produce climatological anomalies that represent the equal but opposite impacts of the ENSOWARM experiment, as the isotopic anomalies associated with ENSOWARM conditions are generally stronger than with ENSOCOOL and the spatial patterns of change distinct. Also, when the same ENSO-like surface temperature anomalies are imposed on the mid-Holocene, the hydrological response is muted, relative to the preindustrial. Mid-Holocene changes in moisture sources to the analyzed regions across the Pacific reveal potentially complex relationships between ENSO-like conditions and boundary conditions. Given the complex impacts of ENSO-like conditions on various aspects of the hydrological cycle, we suggest that proxy record insights into paleo-ENSO variability are most likely to be robust when synthesized from a network of many spatially diverse archives, which can account for the potential nonstationarity of ENSO teleconnections under different boundary conditions
Development of a Health Survey Instrument for 5- to 8-Year-Old Youths
Measuring program outcomes is required for documenting effectiveness of interventions with youths participating in programs funded through the U.S. Department of Agriculture\u27s Children, Youth, and Families at Risk (CYFAR) initiative. The California CYFAR program provided programming for youths aged 5–8, which necessitated the development of an age-appropriate survey measure. Evaluating younger youths to assess healthful living outcomes is challenging, especially with youths in kindergarten through second grade. This article addresses development and testing of the measure and resultant lessons learned. Recommendations for developing an evaluation survey for younger youths are provided
Mindfulness-Oriented Recovery Enhancement versus CBT for co-occurring substance dependence, traumatic stress, and psychiatric disorders: Proximal outcomes from a pragmatic randomized trial
In clinical settings, there is a high comorbidity between substance use disorders, psychiatric disorders, and traumatic stress. As such, transdiagnostic therapies are needed to address these co-occurring issues efficiently. The aim of the present study was to conduct a pragmatic randomized controlled trial comparing Mindfulness-Oriented Recovery Enhancement (MORE) to group Cognitive-Behavioral Therapy (CBT) and treatment-as-usual (TAU) for previously homeless men residing in a therapeutic community. Men with co-occurring substance use and psychiatric disorders, as well as extensive trauma histories, were randomly assigned to 10 weeks of group treatment with MORE (n=64), CBT (n=64), or TAU (n=52). Study findings indicated that from pre- to post-treatment MORE was associated with modest yet significantly greater improvements in substance craving, post-traumatic stress, and negative affect than CBT, and significantly greater improvements in post-traumatic stress and positive affect than TAU. A significant indirect effect of MORE on decreasing craving and post-traumatic stress by increasing dispositional mindfulness was observed, suggesting that MORE may target these issues via enhancing mindful awareness in everyday life. This pragmatic trial represents the first head-to-head comparison of MORE against an empirically-supported treatment for co-occurring disorders. Results suggest that MORE, as an integrative therapy designed to bolster self-regulatory capacity, may hold promise as a treatment for intersecting clinical conditions
Modeling Insights into Deuterium Excess as an Indicator of Water Vapor Source Conditions
Deuterium excess (d) is interpreted in conventional paleoclimate reconstructions as a tracer of oceanic source region conditions, such as temperature, where precipitation originates. Previous studies have adopted co-isotopic approaches to estimate past changes in both site and oceanic source temperatures for ice core sites using empirical relationships derived from conceptual distillation models, particularly Mixed Cloud Isotopic Models (MCIMs). However, the relationship between d and oceanic surface conditions remains unclear in past contexts. We investigate this climate-isotope relationship for sites in Greenland and Antarctica using multiple simulations of the water isotope-enabled Goddard Institute for Space Studies (GISS) ModelE-R general circulation model and apply a novel suite of model vapor source distribution (VSD) tracers to assess d as a proxy for source temperature variability under a range of climatic conditions. Simulated average source temperatures determined by the VSDs are compared to synthetic source temperature estimates calculated using MCIM equations linking d to source region conditions. We show that although deuterium excess is generally a faithful tracer of source temperatures as estimated by the MCIM approach, large discrepancies in the isotope-climate relationship occur around Greenland during the Last Glacial Maximum simulation, when precipitation seasonality and moisture source regions were notably different from present. This identified sensitivity in d as a source temperature proxy suggests that quantitative climate reconstructions from deuterium excess should be treated with caution for some sites when boundary conditions are significantly different from the present day. Also, the exclusion of the influence of humidity and other evaporative source changes in MCIM regressions may be a limitation of quantifying source temperature fluctuations from deuterium excess in some instances
Chronicles of Oklahoma
Article relates the journey of one particular man, Lewis Warren Neatherlin, in his journey herding cattle along the Great Western Cattle Trail in 1876, through an excerpt from a previously undiscovered journal donated by his granddaughter. Leo Kelley provides historical context through annotation and a detailed introduction
- …