Isolation and purification of mitochondria

Isolation and purification of mitochondri

Surface layer O3 and NOx in the Arctic: the in uence of boundary layer dynamics, snowpack chemistry, surface exchanges, and seasonality

The snowpack is a region of active chemistry. Aqueous chemistry in a quasi-liquid layer on snow grains and gas-phase chemical reactions in snow interstitial air can lead to the production or destruction of important trace gases. Physical transport parameters such as wind pumping and diffusion affect the vertical distribution of gases within the snowpack. The resulting emission or uptake of trace gases at the atmosphere-snowpack interface can have significant influence on the chemistry of the lower atmosphere. In this work the dynamic interactions between the snowpack and atmosphere are examined from multiple perspectives. The primary focus is on ozone (O3) and nitrogen oxides (NOx) in the Arctic, a region undergoing widespread environmental change. To investigate an ice-sheet location with year round snow cover data from a two-year campaign at Summit, Greenland are implemented. At Summit this study examines (1) the processes contributing to vigorous chemistry in snow interstitial air, and (2) the role of the boundary layer over snow in determining surface layer NOx. Physical and chemical processes are shown to contribute to distinct seasonal and diurnal cycles of O3, NO, and NO2 in the snowpack. Boundary layer depths estimated from sonic anemometer turbulence quantities are used alongside sodar-derived values to show that the depth of the stable to weakly stable boundary layer at Summit was not a primary factor in determining NOx in early summer. Motivated by observations of an increase in the length of the snow-free season in the Arctic in recent decades, data from a one-year experiment at the seasonally-snow covered location of Toolik Lake, AK are also incorporated. This study shows the first observations of springtime ozone depletion events at a location over 200 km from the coast in the Arctic. FLEXPART analysis is used to illustrate that these inland events are linked to transport conditions. Lastly at this location, eddy-covariance O3 fluxes were calculated to characterize deposition of O3&nbsp;to the Arctic tundra surface in the summertime. Surface deposition in combination with stability conditions is shown to contribute to the development of a diurnal cycle in surface O3&nbsp;with amplitude ranging 5 to 35 ppbv.</p

Granular Packings: Nonlinear elasticity, sound propagation and collective relaxation dynamics

Experiments on isotropic compression of a granular assembly of spheres show that the shear and bulk moduli vary with the confining pressure faster than the 1/3 power law predicted by Hertz-Mindlin effective medium theories (EMT) of contact elasticity. Moreover, the ratio between the moduli is found to be larger than the prediction of the elastic theory by a constant value. The understanding of these discrepancies has been a longstanding question in the field of granular matter. Here we perform a test of the applicability of elasticity theory to granular materials. We perform sound propagation experiments, numerical simulations and theoretical studies to understand the elastic response of a deforming granular assembly of soft spheres under isotropic loading. Our results for the behavior of the elastic moduli of the system agree very well with experiments. We show that the elasticity partially describes the experimental and numerical results for a system under compressional loads. However, it drastically fails for systems under shear perturbations, particularly for packings without tangential forces and friction. Our work indicates that a correct treatment should include not only the purely elastic response but also collective relaxation mechanisms related to structural disorder and nonaffine motion of grains.Comment: 21 pages, 13 figure

Coming Home: Health Status and Homelessness Risk of Older Pre-release Prisoners

Older adults comprise an increasing proportion of the prison and homeless populations. While older age is associated with adverse post-release health events and incarceration is a risk factor for homelessness, the health status and homelessness risk of older pre-release prisoners are unknown. Moreover, most post-release services are geared towards veterans; it is unknown whether the needs of non-veterans differ from those of veterans. To assess health status and risk of homelessness of older pre-release prisoners, and to compare veterans with non-veterans. Cross-sectional study of 360 prisoners (≥55&nbsp;years of age) within 2&nbsp;years of release from prison using data from the 2004 Survey of Inmates in State and Federal Correctional Facilities. Veteran status, health status (based on self-report), and risk of homelessness (homelessness before arrest). Mean age was 61&nbsp;years; 93.8% were men and 56.5% were white. Nearly 40% were veterans, of whom 77.2% reported likely VA service eligibility. Veterans were more likely to be white and to have obtained a high school diploma or GED. Overall, 79.1% reported a medical condition and 13.6% reported a serious mental illness. There was little difference in health status between veterans and non-veterans. Although 1 in 12 prisoners reported a risk factor for homelessness, the risk factors did not differ according to veteran status. Older pre-release prisoners had a high burden of medical and mental illness and were at risk for post-release homelessness regardless of veteran status. Reentry programs linking pre-release older prisoners to medical and psychiatric services and to homelessness prevention programs are needed for both veterans and non-veterans

A Community-Based Participatory Research Approach to Developing the Harvest for Healthy Kids Curriculum

Background: A diet rich in fruits and vegetables is associated with reduced risk of diet-related chronic diseases. However, fewer than half of children in the United States consume the recommended amount. Objectives: This article describes the community-based participatory research (CBPR) process used to develop the Harvest for Healthy Kids curriculum. Methods: Harvest for Healthy Kids is a intervention research project designed to increase access to and intake of fruits and vegetables among preschoolers enrolled in Head Start. The curriculum is composed of eight kits, each focusing on a different fruit or vegetable. Results: The Harvest for Healthy Kids curriculum was developed through an iterative process in which Head Start teachers were highly involved. The final product reflects the teachers’ experiences using the curriculum and their suggestions for improving. Conclusions: The CBPR process used to develop the Harvest for Healthy Kids curriculum led to a product that is grounded in theory and practice

Intervention leads to improvements in the nutrient profile of snacks served in afterschool programs: a group randomized controlled trial

Widely adopted nutrition policies for afterschool programs (ASPs) focus on serving a fruit/vegetable daily and eliminating sugar-sweetened foods/beverages. The impact of these policies on the nutrient profile of snacks served is unclear. Evaluate changes in macro/micronutrient content of snacks served in ASPs. A 1-year group randomized controlled trial was conducted in 20 ASPs serving over 1700 elementary-age children. Intervention ASPs received a multistep adaptive framework intervention. Direct observation of snack served was collected and nutrient information determined using the USDA Nutrient Database, standardized to nutrients/100 kcal. By post-assessment, intervention ASPs reduced total kcal/snack served by 66 kcal (95CI -114 to -19 kcal) compared to control ASPs. Total fiber (+1.7 g/100 kcal), protein (+1.4 g/100 kcal), polyunsaturated fat (+1.2 g/100 kcal), phosphorous (+49.0 mg/100 kcal), potassium (+201.8 mg/100 kcal), and vitamin K (+21.5 μg/100 kcal) increased in intervention ASPs, while added sugars decreased (-5.0 g/100 kcal). Nutrition policies can lead to modest daily caloric reductions and improve select macro/micronutrients in snacks served. Long-term, these nutritional changes may contribute to healthy dietary habits

Reproductive success of kittiwakes and murres in sequential stages of the nesting period: Relationships with diet and oceanography

Reproductive success is one of the most easily-measured and widely studied demographic parameters of colonial nesting seabirds. Nevertheless, factors affecting the sequential stages (egg laying, incubation, chick-rearing) of reproductive success are less understood. We investigated the separate sequential stages of reproductive success in piscivorous black-legged kittiwakes (Rissa tridactyla) and thick-billed murres (Uria lomvia) using a 36-year dataset (1975–2010) on the major Pribilof Islands (St. Paul and St. George), which have recently had contrasting population trajectories. Our objectives were to evaluate how the proportion of successful nests varied among stages, and to quantify factors influencing the probability of nest success at each stage in each island. We modeled the probability of nest success at each stage using General Linear Mixed Models incorporating broad-scale and local climate variables, and diet as covariates as well as other measures of reproduction such as timing of breeding and reproductive output in the previous year and previous stage. For both species we found: (1) Success in previous stages of the breeding cycle and success in the prior year better explained overall success than any environmental variables. Phenology was also an important predictor of laying success for kittiwakes. (2) Fledging success was lower when chick diets contained oceanic fish found farther from the colonies and small invertebrates, rather than coastal fish species. (3) Differences in reproductive variables at St. Paul and St. George islands did not correspond to population trends between the two islands. Our results highlight the potential importance of adult condition and annual survival to kittiwake and murre productivity and ultimately, populations. Adult condition carrying over from the previous year ultimately seems to drive annual breeding success in a cascade effect. Furthermore, condition and survival appear to be important contributors to population dynamics at each island. Therefore, adult condition and survival prior to breeding, and factors that influence these parameters such as foraging conditions in the non-breeding season, may be important datasets for understanding drivers of seabird demography at the Pribilof Islands.KEYWORDS: USA, Reproductive success, Pribilof Islands, Thick-billed murre, Marine birds, Bering Sea, Black-legged kittiwake, Alaska, DietsThis is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/deep-sea-research-part-ii-topical-studies-in-oceanograph