741 research outputs found

    Crop price indemnified loans for farmers

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    Farmers face a particular set of risks that complicate the decision to borrow. We use a randomized experiment to investigate (1) the role of crop-price risk in reducing demand for credit among famers and (2) how risk mitigation changes farmers’ investment decisions. In rural Ghana, we offer farmers loans with an indemnity component that forgives 50 percent of the loan if crop prices drop below a threshold price. A control group is offered a standard loan product at the same interest rate. We find similar rates of loan uptake among all farmers and little significant impact of the indemnity component on uptake or other outcomes of interest, with the exception of higher likelihoods of garden egg cultivation and sales to market traders rather than at farmgate among recipients of indemnified loans.agricultural credit, clustered randomized control trial, crop price insurance, crop prices, Impact evaluation, underinvestment,

    Gray-matter volume, midbrain dopamine D2/D3 receptors and drug craving in methamphetamine users.

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    Dysfunction of the mesocorticolimbic system has a critical role in clinical features of addiction. Despite evidence suggesting that midbrain dopamine receptors influence amphetamine-induced dopamine release and that dopamine is involved in methamphetamine-induced neurotoxicity, associations between dopamine receptors and gray-matter volume have been unexplored in methamphetamine users. Here we used magnetic resonance imaging and [(18)F]fallypride positron emission tomography, respectively, to measure gray-matter volume (in 58 methamphetamine users) and dopamine D2/D3 receptor availability (binding potential relative to nondisplaceable uptake of the radiotracer, BPnd) (in 31 methamphetamine users and 37 control participants). Relationships between these measures and self-reported drug craving were examined. Although no difference in midbrain D2/D3 BPnd was detected between methamphetamine and control groups, midbrain D2/D3 BPnd was positively correlated with gray-matter volume in the striatum, prefrontal cortex, insula, hippocampus and temporal cortex in methamphetamine users, but not in control participants (group-by-midbrain D2/D3 BPnd interaction, P<0.05 corrected for multiple comparisons). Craving for methamphetamine was negatively associated with gray-matter volume in the insula, prefrontal cortex, amygdala, temporal cortex, occipital cortex, cerebellum and thalamus (P<0.05 corrected for multiple comparisons). A relationship between midbrain D2/D3 BPnd and methamphetamine craving was not detected. Lower midbrain D2/D3 BPnd may increase vulnerability to deficits in gray-matter volume in mesocorticolimbic circuitry in methamphetamine users, possibly reflecting greater dopamine-induced toxicity. Identifying factors that influence prefrontal and limbic volume, such as midbrain BPnd, may be important for understanding the basis of drug craving, a key factor in the maintenance of substance-use disorders

    WILLS-CONSTRUCTION-MEANING OF WORD \u27WIDOW WHEN USED BY TESTATOR

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    Testatrix set up a testamentary trust which was to continue until the death of the last survivor of such of my children, grandchildren and any widow of my son, surviving him as shall be living at my decease. Upon the death of any child the trustee was directed to pay to the husband or widow of such child a part of the principal or an annuity from the income of the trust. Testatrix\u27 son remarried after her death and on his death the trustee brought this action to determine whether the second wife who was living at testatrix\u27 death, was entitled to the annuity. On appeal from a decree of the probate court instructing that no annuity was payable, held, affirmed. A testamentary gift to the widow of another is presumptively a gift only to that other\u27s wife who was known to the testator. Hill v. Aldrich, (Mass. 1951) 96 N.E. (2d) 147

    Systems engineering and integration: Cost estimation and benefits analysis

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    Space Transportation Avionics hardware and software cost has traditionally been estimated in Phase A and B using cost techniques which predict cost as a function of various cost predictive variables such as weight, lines of code, functions to be performed, quantities of test hardware, quantities of flight hardware, design and development heritage, complexity, etc. The output of such analyses has been life cycle costs, economic benefits and related data. The major objectives of Cost Estimation and Benefits analysis are twofold: (1) to play a role in the evaluation of potential new space transportation avionics technologies, and (2) to benefit from emerging technological innovations. Both aspects of cost estimation and technology are discussed here. The role of cost analysis in the evaluation of potential technologies should be one of offering additional quantitative and qualitative information to aid decision-making. The cost analyses process needs to be fully integrated into the design process in such a way that cost trades, optimizations and sensitivities are understood. Current hardware cost models tend to primarily use weights, functional specifications, quantities, design heritage and complexity as metrics to predict cost. Software models mostly use functionality, volume of code, heritage and complexity as cost descriptive variables. Basic research needs to be initiated to develop metrics more responsive to the trades which are required for future launch vehicle avionics systems. These would include cost estimating capabilities that are sensitive to technological innovations such as improved materials and fabrication processes, computer aided design and manufacturing, self checkout and many others. In addition to basic cost estimating improvements, the process must be sensitive to the fact that no cost estimate can be quoted without also quoting a confidence associated with the estimate. In order to achieve this, better cost risk evaluation techniques are needed as well as improved usage of risk data by decision-makers. More and better ways to display and communicate cost and cost risk to management are required

    Water quality as related to possible heavy metal additions in surface and ground water in the Springfield and Joplin areas, Missouri

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    Students supported: 3 MS StudentsSome 165 seasonal water samples were collected and analyzed for heavy metals from surface and subsurface sources in a one hundred mile area around Springfield and Joplin, Missouri, respectively. Joplin is in a former large zinc mining district. Springfield is 72 miles east. Locally, cadmium, lead, zinc and iron exceed acceptable PHS standards for drinking water, but the majority of water samples are well within the established limits. Yet, ten percent of the water wells sampled in the Springfield area and twenty-five percent of those sampled in the Joplin area approached or exceeded the PHS limits of the one or more heavy metals for drinking water. High zinc values are related to known zinc-lead mineralization in both areas. Average cadmium values are slightly higher in Joplin, copper content is similar for both areas, and lead content is slightly higher near Joplin. Surface waters in Joplin are 17 times higher in average zinc content than in Springfield, though shallow wells for both areas are similar in zinc content. Iron is higher and more variable in Joplin. Mercury, in very low quantity in both areas, is somewhat higher in the Springfield area. Some seasonal variation occurs in the heavy metal content in both areas. Alternate sources of water are suggested or those areas having heavy metal content in excess of PHS standards. Effects on living systems within areas containing anomalous heavy metal content are unknown.Project # B-054-MO Agreement # 14-31-0001-360

    Exploring Spatial Patterns of Virginia Tornadoes Using Kernel Density and Space-Time Cube Analysis (1960-2019)

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    This study evaluates the spatial-temporal patterns in Virginia tornadoes using the National Weather Service Storm Prediction Center’s Severe Weather GIS (SVRGIS) database. In addition to descriptive statistics, the analysis employs Kernel Density Estimation for spatial pattern analysis and space-time cubes to visualize the spatiotemporal frequency of tornadoes and potential trends. Most of the 726 tornadoes between 1960–2019 occurred in Eastern Virginia, along the Piedmont and Coastal Plain. Consistent with other literature, both the number of tornadoes and the tornado days have increased in Virginia. While 80% of the tornadoes occurred during the warm season, tornadoes did occur during each month including two deadly tornadoes in January and February. Over the 60-year period, a total of 28 people were killed in the Commonwealth. Most tornado activity took place in the afternoon and early evening hours drawing attention to the temporal variability of risk and vulnerability. Spatial analysis results identify significant, non-random clusters of tornado activity and increasing temporal frequency. While this study improves weather-related literacy and addresses a need in the Commonwealth, more research is necessary to further evaluate the synoptic and mesoscale mechanisms of Virginia tornadoes

    Automatic Detection of Aircraft Emergency Landing Sites

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    An automatic landing site detection algorithm is proposed for aircraft emergency landing. Emergency landing is an unplanned event in response to emergency situations. If, as is unfortunately usually the case, there is no airstrip or airfield that can be reached by the un-powered aircraft, a crash landing or ditching has to be carried out. Identifying a safe landing site is critical to the survival of passengers and crew. Conventionally, the pilot chooses the landing site visually by looking at the terrain through the cockpit. The success of this vital decision greatly depends on the external environmental factors that can impair human vision, and on the pilot\u27s flight experience that can vary significantly among pilots. Therefore, we propose a robust, reliable and efficient algorithm that is expected to alleviate the negative impact of these factors. We present only the detection mechanism of the proposed algorithm and assume that the image enhancement for increased visibility, and image stitching for a larger field-of-view have already been performed on the images acquired by aircraft-mounted cameras. Specifically, we describe an elastic bound detection method which is designed to position the horizon. The terrain image is divided into non-overlapping blocks which are then clustered according to a roughness measure. Adjacent smooth blocks are merged to form potential landing sites whose dimensions are measured with principal component analysis and geometric transformations. If the dimensions of the candidate region exceed the minimum requirement for safe landing, the potential landing site is considered a safe candidate and highlighted on the human machine interface. At the end, the pilot makes the final decision by confirming one of the candidates, also considering other factors such as wind speed and wind direction, etc. Preliminary results show the feasibility of the proposed algorithm

    Analysis of Listeria using exogenous volatile organic compound metabolites and their detection by static headspace–multi-capillary column–gas chromatography–ion mobility spectrometry (SHS–MCC–GC–IMS)

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    Listeria monocytogenes is a Gram-positive bacterium and an opportunistic food-borne pathogen which poses significant risk to the immune-compromised and pregnant due to the increased likelihood of acquiring infection and potential transmission of infection to the unborn child. Conventional methods of analysis suffer from either long turn-around times or lack the ability to discriminate between Listeria spp. reliably. This paper investigates an alternative method of detecting Listeria spp. using two novel enzyme substrates that liberate exogenous volatile organic compounds in the presence of α-mannosidase and d-alanyl aminopeptidase. The discriminating capabilities of this approach for identifying L. monocytogenes from other species of Listeria are investigated. The liberated volatile organic compounds (VOCs) are detected using an automated analytical technique based on static headspace–multi-capillary column–gas chromatography–ion mobility spectrometry (SHS–MCC–GC–IMS). The results obtained by SHS–MCC–GC–IMS are compared with those obtained by the more conventional analytical technique of headspace–solid phase microextraction–gas chromatography–mass spectrometry (HS–SPME–GC–MS). The results found that it was possible to differentiate between L. monocytogenes and L. ivanovii, based on their VOC response from α-mannosidase activity

    A chromatographic approach to distinguish Gram-positive from Gram-negative bacteria using exogenous volatile organic compound metabolites

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    This paper utilized L-alanine aminopeptidase activity as a useful approach to distinguish between Gram-negative and Gram-positive bacteria. This was done using two enzyme substrates, specifically 2-amino-N-phenylpropanamide and 2-amino-N-(4-methylphenyl)propanamide which liberated the volatile compounds aniline and p-toluidine, respectively. Two complementary analytical techniques have been used to identify and quantify the VOCs, specifically static headspace multicapillary column gas chromatography ion mobility spectrometry (SHS-MCC-GC-IMS) and headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS). Superior limits of detection were obtained using HS-SPME-GC-MS, typically by a factor of x6 such that the LOD for aniline was 0.02 ÎĽg/mL and 0.01 ÎĽg/mL for p-toluidine. In addition, it was also possible to determine indole interference-free by HS-SPME-GC-MS at an LOD of 0.01 ÎĽg/mL. The approach was applied to a range of selected bacteria: 15 Gram-negative and 7 Gram-positive bacteria. Use of pattern recognition, in the form of Principal Component Analysis, confirmed that it is possible to differentiate between Gram-positive and Gram-negative bacteria using the enzyme generated VOCs, aniline and p-toluidine. The exception was Stenotrophomonas maltophilia which showed negligible VOC concentrations for both aniline and p-toluidine, irrespective of the analytical techniques used and hence was not characteristic of the other Gram-negative bacteria investigated. The developed methodology has the potential to be applied for clinical and food applications
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