12,065 research outputs found

    Evolution of basin and range structure in the Ruby Mountains and vicinity, Nevada

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    Results from various age dating techniques, seismic reflection profiling hydrocarbon maturation studies, and structural analysis were used to evaluate the Cenozoic deformation in the Ruby Mountains and adjoining ranges (pinyon Range and Cortez Range) in Elko and Eureka Counties, Nevada. Age dating techniques used include potassium-argon ages of biotites from granites published by Kistler et al. (1981) and fission track ages from apatite and zircon. Fission track ages from apatite reflect a closing temperature of 100 plus or minus 20 deg C. Zircon fission track ages reflect a closing temperature of 175 plus or minus 25 deg C and potassium-argon ages from brotite reflect a closing temperature of 250 plus or minus 30 deg C. Thus these results allow a reasonably precise tracking of the evolution of the ranges during the Cenozoic. Seismic reflection data are available from Huntington Valley. Access to seismic reflection data directly to the west of the Harrison Pass Pluton in the central Ruby Mountains was obtained. In addition results are available from several deep exploration holes in Huntington Valley

    Milli-second Oscillations in the Persistent and Bursting Flux of Aql X-1 During an Outburst

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    The Rossi X-Ray Timing Explorer observed the soft X-Ray transient Aql X-1 during its outburst in February and March 1997. We report the discovery of quasi-periodic oscillations (QPOs) in its persistent flux with frequencies in the range of 740 to 830 Hz, Q-value of over 100, and a fractional RMS amplitude of (6.8 +- 0.6)%, and nearly coherent oscillations (NCOs) during a Type-I burst with a frequency of 549 Hz. The frequency of the QPOs in the persistent flux is correlated with the mass accretion rate on time scale of hours, but not on time scale of days. This is most likely the manifestation in a single source of the kHz QPO puzzle observed among many sources, i.e., on the one hand, individual sources show a correlation between the QPO frequency and the inferred mass accretion rate, on the other hand, the dozen or so sources with luminosities spanning two decades have essentially the same QPO frequencies. We propose that this multi-valued QPO frequency and mass accretion rate correlation indicates the existence of many similar regimes of the accretion disk. These regimes, with a very similar energy spectrum and QPO frequency, are distinguished from each other by the mass accretion rate or the total X-ray flux. The NCOs during the burst can be made almost perfectly coherent by taking into account a large frequency derivative. This strongly suggests that this frequency is related to the neutron star spin frequency. The large frequency derivative is attributable to the expansion or contraction of the neutron star photosphere during the burst.Comment: 6 pages, LaTex (aas2pp4), Accepted for publication in ApJ Let

    Direct Marketing Edamame (Glycine max [L.] Merrill) to Professional Chefs

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    A consumer-research study was conducted in Metro-Philadelphia to determine professional chef demand for edamame (Glycine max [L.] Merrill). Cultivar preferences and partiality for shelled or inshell edamame were also investigated. The majority of chefs indicated that they were very likely to use edamame again, and many were interested in acquiring Pennsylvania-grown edamame from small-acreage growers. Most chefs liked all three cultivars, and the majority preferred shelled edamame. Using this methodology, Extension personnel can continue to investigate professional chef demand and preferences for specialty crops and provide grower clientele with information on how to best meet consumer needs

    Barriers to Summer Food Service Program (SFSP) Implementation Before and After COVID-19: A Qualitative, Collective Case Study

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    Objectives: SFSP, as a federal food assistance program, could ensure that children have sufficient nutritious food during summer. According to a 2016 USDA report, only 0.4–0.6% of eligible children participated in this program in Nebraska, which makes for one of the lowest SFSP participation rates in the U.S. This study aims to better understand how the COVID-19 pandemic has impacted SFSP implementation in urban and rural settings across the state. Conclusions: Insights from this study may inform the development of policies that expand food access to vulnerable families. On the organizational level, this includes providing participating kids and their parents with both meal distribution options - meal sites and delivery options - during summer. On the policy level, this calls for revising the eligibility of SFSP by decreasing the threshold level from 50% to 30% to allow more schools in low-income neighborhoods to participate

    Serving Refugees in a Pandemic: Insights from Yazidis in the Midwest

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    There is a critical need for research to examine factors that hinder or facilitate access to healthcare in the context of COVID-19. The coronavirus pandemic has exacerbated barriers to healthcare for marginalized communities globally, leaving many without access to needed health services. Resettled refugees, in particular, must grapple with added challenges to locating and obtaining culturally appropriate healthcare services. Recent focus groups shed light on the experiences of Yazidi refugees in the U.S. Midwest during COVID-19. Yazidis are a historically persecuted religious and ethnic minority group from northern Iraq (Kizilhan, 2017). Many Yazidis migrated to the U.S. on Special Immigrant Visas after providing interpretation services for the U.S. Army. Focus groups reflected diverse perspectives from health care providers, social workers, Yazidi community members, and cultural centers. Findings reveal four critical areas that limit access to healthcare: (1) language barriers; (2) economic barriers; (3) social barriers; and (4) cultural stigma. In this commentary, we explore how these barriers contribute to adverse health experiences and outcomes during the COVID-19 pandemic, and offer insights relevant to public health practice with marginalized communities

    Water vapour source impacts on oxygen isotope variability in tropical precipitation during Heinrich events

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    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

    Simulated Greenland Surface Mass Balance in the GISS ModelE2 GCM: Role of the Ice Sheet Surface

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    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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