194 research outputs found

    Center pivot irrigation in Nebraska : an institutional analysis case study

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    This paper is one of a series resulting from institutional analysis of photovoltaic (PV) acceptance. It reports the results of a study of institutional factors influencing acceptance of center-pivot irrigation in the Nebraska agricultural community. Center-pivot irrigation (CP) was an interesting topic for study because (1) it was a major recently introduced technological innovation in agriculture which (2) had potentially detrimental attributes--water and energy intensity. A brief historical review of the introduction and acceptance of center-pivot irrigation in the Nebraska agricultural community is presented. Institutions which were a likely part of this institutional arena relative to CP introduction and acceptance were identified. Their likely responses were hypothesized, then data collected regarding actual response. Three broad conslusions are drawn. First, there were definite, even controlling institutional influences in the acceptance of CP in the Nebraska agricultural community. Second, acceptance was facilitated in the Nebraska agricultural community because the innovation differentiation process yielded secondary attributes of CP that met prevailing social orders--productivity, automation, and felt need. Third, the innovation differentiation process for CP in the Nebraska agricultural community yielded both transformation and disconnection of detrimental attributes, creating the circumstances for attribute redefinition in the first instance and another innovation in the second instance.DOE Contract no. EX-76-A-01-2295

    Medical Care of AIDS in New England: Costs and Implications

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    This article presents an overview of cost issues related to AIDS. Data from the Massachusetts Cost of AIDS Study are combined with epidemiological projections to estimate the cost of treating people diagnosed with AIDS in New England. Aggregate inpatient, ambulatory, and home care costs are estimated to be 96.9millionand96.9 million and 524.8 million through 1987 and 1991, respectively. These estimates represent a relatively small percentage of total health care costs for all illnesses over the same time period. The authors find that the cost of treating AIDS does not affect all health care providers uniformly and therefore argue that appropriate measures must be developed to assist those impacted disproportionately. Reduction of inpatient hospital days through the creation of subacute care centers, subsidy programs for medical care providers serving large numbers of uninsured or underinsured AIDS patients and education to prevent new cases are recommended to continue the availability of medical care for people with AIDS

    The effects of institutions on innovation : the case of center-pivot irrigation

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    Thesis. 1978. M.C.P.--Massachusetts Institute of Technology. Dept. of Urban Studies and Planning.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.Includes bibliographical references.by Stewart Landers.M.C.P

    TEMGYM Advanced: Software for Electron Lens Aberrations and Parallelised Electron Ray Tracing

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    Characterisation of the electron beams trajectory in an electron microscope is possible in a few select commercial software packages, but these tools and their source code are not available in a free and accessible manner. This paper introduces the free and open-source software TEMGYM Advanced, which implements ray tracing methods that calculate the path of electrons through a magnetic or electrostatic lens and allow evaluation of the first-order properties and third-order geometric aberrations. Validation of the aberration coefficient calculations is performed by implementing two independent methods – the aberration integral and differential algebra (DA) methods and by comparing the results of each. This paper also demonstrates parallelised electron ray tracing through a series of magnetic components, which enables near real-time generation of a physically accurate beam-spot including aberrations and brings closer the realisation of a digital twin of an electron microscope. TEMGYM Advanced represents a valuable resource for the electron microscopy community, providing an accessible and open source means of characterising electron lenses. This software utilises the Python programming language to complement the growing ecosystem of free and open-source software within the electron microscopy community, and to facilitate the application of machine learning to an electron microscope digital twin for instrument automation. The software is available under GNU Public License number Three (GPL 3)

    A Multi-Year Survey of Meiofaunal Abundance From the Northern Gulf of Mexico Continental Shelf and Slope

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    This 3-yr (2007–09) survey documented meiofauna abundance across the northern Gulf of Mexico on the continental shelf and slope from south Texas to south Florida. Sediment samples were collected from depths ranging from 29 to 509 m (average = 132 m) on the National Oceanic and Atmospheric Admistration ship Gordon Gunter during the annual fall small pelagics fish-sampling cruise. A total of 259 sediment samples from 99 ShipekH grabs were analyzed. Meiofauna were isolated from the sediment by sieving (63-mm sieve) and concentrating the organisms via LudoxH centrifugation. Each year the two dominant animal groups were nematodes and copepods, followed by polychaetes, nauplii, kinorhynchs, priapulid loricate larvae, tardigrades, and Acari. Spearman correlations indicated that abundances of nematodes, copepods, polychaetes, and nauplii were positively related, and that all meiofauna groups decreased in abundance with increasing longitude (farther west). Abiotic variables such as salinity, temperature, and depth did not correlate with any meiofauna group. Distribution maps of the animals indicated a clear geographic trend that was supported statistically, in that the animal groups were more concentrated in Florida samples rather than the central and western continental shelf

    A Multi-Year Survey of Meiofaunal Abundance From the Northern Gulf of Mexico Continental Shelf and Slope

    Get PDF
    This 3-yr (2007–09) survey documented meiofauna abundance across the northern Gulf of Mexico on the continental shelf and slope from south Texas to south Florida. Sediment samples were collected from depths ranging from 29 to 509 m (average = 132 m) on the National Oceanic and Atmospheric Administration ship Gordon Gunter during the annual fall small pelagics fish-sampling cruise. A total of 259 sediment samples from 99 Shipek® grabs were analyzed. Meiofauna were isolated from the sediment by sieving (63-μm sieve) and concentrating the organisms via Ludox® centrifugation. Each year the two dominant animal groups were nematodes and copepods, followed by polychaetes, nauplii, kinorhynchs, priapulid loricate larvae, tardigrades, and Acari. Spearman correlations indicated that abundances of nematodes, copepods, polychaetes, and nauplii were positively related, and that all meiofauna groups decreased in abundance with increasing longitude (farther west). Abiotic variables such as salinity, temperature, and depth did not correlate with any meiofauna group. Distribution maps of the animals indicated a clear geographic trend that was supported statistically, in that the animal groups were more concentrated in Florida samples rather than the central and western continental shelf

    Review of the prevalence of diabetic retinopathy in Indigenous Australians

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    Author version made available in accordance with Publisher copyright policy.The purpose of this review is to compare the prevalence of diabetic retinopathy (DR) between Indigenous and non-Indigenous Australians with Diabetes Mellitus (DM). Australian DR prevalence data from 6 Indigenous studies (n = 2865) and 5 non-Indigenous studies (n = 9801) conducted between 1985 and 2013 were included for analysis. Estimated prevalence of any DR among Indigenous Australians with DM was 23.4% compared with 28.9% for non-Indigenous Australians (χ2 = 26.9, P < 0.001). In studies performed after 1990, a significantly higher rate of diabetic macular edema was found in Indigenous compared with non-Indigenous Australians with DM (7.6% versus 4.9%, χ2 = 6.67, P = 0.01). Although there are limitations in comparing these studies, one explanation for the observed data could be a model in which Indigenous Australians are relatively resistant to early stage DR, but with a subset progressing to sight threatening DR due to individual genetic and environmental susceptibility factors coupled with poor glycemic control

    Meiofauna and Trace Metals From Sediment Collections in Florida After the Deepwater Horizon Oil Spill

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    Sediment from the Florida Gulf continental shelf was collected from 18 sites during October and November 2010 for meiofauna and trace-metals analysis. Collections were obtained using a Shipek® grab on the National Oceanic and Atmospheric Administration ship Pisces and spanned from the head of the DeSoto Canyon to off the southern end of the Florida peninsula approximately following the 100–200-m contour. Mean abundance of the dominant meiofaunal groups (nematodes, copepods, and polychaetes) was unchanged when compared with 2007–2009 data. Nematodes and copepods correlated positively with each other, and negatively with latitude and longitude, suggesting that there were higher densities in southern Florida. These results contrast with those from 2007–2009 in that previously nematodes had no correlation with latitude or longitude in Florida. Nickel (Ni) and vanadium (V) concentrations were higher in the western Florida locations and correlated positively with increasing depth. No relationship was found between Ni, V, and meiofauna densities

    A mouse model of high trait anxiety shows reduced heart rate variability that can be reversed by anxiolytic drug treatment

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    Increasing evidence suggests that specific physiological measures may serve as biomarkers for successful treatment to alleviate symptoms of pathological anxiety. Studies of autonomic function investigating parameters such as heart rate (HR), HR variability and blood pressure (BP) indicated that HR variability is consistently reduced in anxious patients, whereas HR and BP data show inconsistent results. Therefore, HR and HR variability were measured under various emotionally challenging conditions in a mouse model of high innate anxiety (high anxiety behaviour; HAB) vs. control normal anxiety-like behaviour (NAB) mice. Baseline HR, HR variability and activity did not differ between mouse lines. However, after cued Pavlovian fear conditioning, both elevated tachycardia and increased fear responses were observed in HAB mice compared to NAB mice upon re-exposure to the conditioning stimulus serving as the emotional stressor. When retention of conditioned fear was tested in the home cage, HAB mice again displayed higher fear responses than NAB mice, while the HR responses were similar. Conversely, in both experimental settings HAB mice consistently exhibited reduced HR variability. Repeated administration of the anxiolytic NK1 receptor antagonist L-822429 lowered the conditioned fear response and shifted HR dynamics in HAB mice to a more regular pattern, similar to that in NAB mice. Additional receiver-operating characteristic (ROC) analysis demonstrated the high specificity and sensitivity of HR variability to distinguish between normal and high anxiety trait. These findings indicate that assessment of autonomic response in addition to freezing might be a useful indicator of the efficacy of novel anxiolytic treatments
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