2,079 research outputs found
Perceptions of Green Eating Behaviors on College Campuses in an Urban vs. Rural Setting
Background: Green Eating is a multidisciplinary approach to health in economic, public health, and environmental issues. GE has an evident impact on the quality of life in young adults, especially those on college campuses. Current evidence already supports an improved dietary intake in those who adopt GE behaviors. Objective: To determine if a universityās campus location affects first-year studentsā exposure to green eating. We hypothesize that first-year students on university campuses located in urban settings are more likely to report GE awareness and practices than in rural settings. Methods: First-year students were recruited for the GetFruved study in late summer 2015 via email and data collection begun early fall 2015. The total number of participants was 1,149. Analysis: A cross-sectional, secondary analysis was completed. Green eating variables were dichotomized into āAlways/Oftenā and āSometimes/Rarely/Neverā and logistic regression was used to determine the relationship between green eating and self-reported region while controlling for gender, vegetarian status, and residence hall status. Results: Of the 25 green eating questions analyzed, 17 were significantly associated with region. Those who live in the NE are 83% more likely to consider themselves a green eater as compared to those in the Midwest (p=0.008). SW is four times (4.02) more likely to purchase meat that is āfree-rangeā or āgrass-fedā with NE (2.69) and SE (1.83) to follow. SE was the lone significant region for āhow often do you shop at farmers marketsā (0.58) and āeating minimal processed food is better for my healthā (1.61). Residence hall was only significant for one question (p=Conclusions: Students living in urban areas are more inclined to always/often report positive GE eating behaviors opposed those in rural areas. Positive behaviors toward in GE in young adults can shift the consumer demand from low-cost convivence food to better quality foods and therefore, largely impact their diets
Dynamical ultrafast all-optical switching of planar GaAs/AlAs photonic microcavities
The authors study the ultrafast switching-on and -off of planar GaAs/AlAs
microcavities. Up to 0.8% refractive index changes are achieved by optically
exciting free carriers at 1720 nm and a pulse energy of 1.8 micro Joules. The
cavity resonance is dynamically tracked by measuring reflectivity versus time
delay with tunable laser pulses, and is found to shift by as much as 3.3
linewidths within a few picoseconds. The switching-off occurs with a decay time
of around 50 ps. The authors derive the dynamic behavior of the carrier density
and of the complex refractive index. They propose that the inferred 10 GHz
switching rate may be tenfold improved by optimized sample growth.Comment: 1.) Replaced figure 1 (linear reflectivity) with a more recent and
improved measurement 2.) Included a Figure of Merit for switching and
compared to other recent contributions 3.) Explained more precisely the
effect of embedded Quantum Dots (namely no effect on measurement) 4.) Changed
wording in a few place
Haldane's rule revisited : do hybrid females have a shorter lifespan? : survival of hybrids in a recent contact zone between two large gull species
Haldaneās rule predicts that particularly high fitness reduction should affect the heterogametic sex of interspecific hybrids. Despite the fact that hybridization is widespread in birds, survival of hybrid individuals is rarely addressed in studies of avian hybrid zones, possibly because of methodological constraints. Here, having applied capture-mark-recapture models to an extensive, 19-year-long dataset on individually marked birds, we estimate annual survival rates of hybrid individuals in the hybrid zone between herring (Larus argentatus) and Caspian (L. cachinnans) gulls. In both parental species, males have a slightly higher survival rate than females (model-weighted mean Ā± SE: herring gull males 0.88 Ā± 0.01, females 0.87 Ā± 0.01, Caspian gull males 0.88 Ā± 0.01, females 0.87 Ā± 0.01). Hybrid males do not survive for a shorter time than non-hybrid ones (0.88 Ā± 0.01), whereas hybrid females have the lowest survival rate among all groups of individuals (0.83 Ā± 0.03). This translates to a shorter adult (reproductive) lifespan (on average by 1.7-1.8 years, i.e. ca 25%) compared to non-hybrid females. We conclude that, in line with Haldaneās rule, the lower survival rate of female hybrids may contribute to selection against hybrids in this hybrid zone
Explaining the effectiveness of performance-based logistics: a quantitative examination
The article of record as published may be located at http://dx.doi.org/10.1108/09574091111181354Purpose ā Performance-based logistics (PBL) strategies are providing governments and for-profit
organizations with a contractual mechanism that reduces the life cycle costs of their systems. PBL
accomplishes this by establishing contracts that focus on the delivery of performance not parts. PBL
establishes a metric based governance structure where suppliers make more profit when they invest in
logistics process improvements, or system redesign, that reduces total cost of ownership. While work
has been done to outline an overall PBL theoretical framework, the underlying theory explaining the
enablers that lead to organizational and team-level, team-goal alignment associated with the PBL
governance structure requires testing. The purpose of this paper is to quantitatively test previously
posited relationships between enablers of PBL and PBL effectiveness. An additional objective is to
explore any differences in PBL effectiveness between different business sectors.This material is based upon work supported by the Naval Postgraduate School Acquisition Research Program under Grant No. N00244-10-1-0074
A System of Conservative Regridding for Ice-Atmosphere Coupling in a General Circulation Model (GCM)
The method of elevation classes, in which the ice surface model is run at multiple elevations within each grid cell, has proven to be a useful way for a low-resolution atmosphere inside a general circulation model (GCM) to produce high-resolution downscaled surface mass balance fields for use in one-way studies coupling atmospheres and ice flow models. Past uses of elevation classes have failed to conserve mass and energy because the transformation used to regrid to the atmosphere was inconsistent with the transformation used to downscale to the ice model. This would cause problems for two-way coupling. A strategy that resolves this conservation issue has been designed and is presented here. The approach identifies three grids between which data must be regridded and five transformations between those grids required by a typical coupled atmosphere-ice flow model. This paper develops a theoretical framework for the problem and shows how each of these transformations may be achieved in a consistent, conservative manner. These transformations are implemented in Glint2, a library used to couple atmosphere models with ice models. Source code and documentation are available for download. Confounding real-world issues are discussed, including the use of projections for ice modeling, how to handle dynamically changing ice geometry, and modifications required for finite element ice models
Simulated Greenland Surface Mass Balance in the GISS ModelE2 GCM: Role of the Ice Sheet Surface
The rate of growth or retreat of the Greenland and Antarctic ice sheets remains a highly uncertain component of future sea level change. Here we examine the simulation of Greenland ice sheet surface mass balance (GrIS SMB) in the NASA Goddard Institute for Space Studies (GISS) ModelE2 General Circulation Model (GCM). GCMs are often limited in their ability to represent SMB compared with polarregion Regional Climate Models (RCMs). We compare ModelE2 simulated GrIS SMB for presentday (19962005) simulations with fixed ocean conditions, at a spatial resolution of 2 latitude by 2.5 longitude (~200 km), with SMB simulated by the Modle Atmosphrique Rgionale (MAR) RCM (19962005 at a 25 km resolution). ModelE2 SMB agrees well with MAR SMB on the whole, but there are distinct spatial patterns of differences and large differences in some SMB components. The impact of changes to the ModelE2 surface are tested, including a subgridscale representation of SMB with surface elevation classes. This has a minimal effect on ice sheetwide SMB, but corrects local biases. Replacing fixed surface albedo with satellitederived values and an agedependent scheme has a larger impact, increasing simulated melt by 60100%. We also find that lower surface albedo can enhance the effects of elevation classes. Reducing ModelE2 surface roughness length to values closer to MAR reduces sublimation by ~50%. Further work is required to account for meltwater refreezing in ModelE2, and to understand how differences in atmospheric processes and model resolution influence simulated SMB
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