193 research outputs found

    Temporary Nerve Block at Selected Digits Revealed Hand Motor Deficits in Grasping Tasks

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    Peripheral sensory feedback plays a crucial role in ensuring correct motor execution throughout hand grasp control. Previous studies utilized local anesthesia to deprive somatosensory feedback in the digits or hand, observations included sensorimotor deficits at both corticospinal and peripheral levels. However, the questions of how the disturbed and intact sensory input integrate and interact with each other to assist the motor program execution, and whether the motor coordination based on motor output variability between affected and non-affected elements (e.g., digits) becomes interfered by the local sensory deficiency, have not been answered. The current study aims to investigate the effect of peripheral deafferentation through digital nerve blocks at selective digits on motor performance and motor coordination in grasp control. Our results suggested that the absence of somatosensory information induced motor deficits in hand grasp control, as evidenced by reduced maximal force production ability in both local and non-local digits, impairment of force and moment control during object lift and hold, and attenuated motor synergies in stabilizing task performance variables, namely the tangential force and moment of force. These findings implied that individual sensory input is shared across all the digits and the disturbed signal from local sensory channel(s) has a more comprehensive impact on the process of the motor output execution in the sensorimotor integration process. Additionally, a feedback control mechanism with a sensation-based component resides in the formation process for the motor covariation structure

    Holocene multidecadal and multicentennial droughts affecting Northern California and Nevada

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    Continuous, high-resolution δ18O records from cored sediments of Pyramid Lake, Nevada, indicate that oscillations in the hydrologic balance occurred, on average, about every 150 years (yr) during the past 7630 calendar years (cal yr). The records are not stationary; during the past 2740 yr, drought durations ranged from 20 to 100 yr and intervals between droughts ranged from 80 to 230 yr. Comparison of tree-ring-based reconstructions of climate change for the past 1200 yr from the Sierra Nevada and the El Malpais region of northwest New Mexico indicates that severe droughts associated with Anasazi withdrawal from Chaco Canyon at 820 cal yr BP (calendar years before present) and final abandonment of Chaco Canyon, Mesa Verde, and the Kayenta area at 650 cal yr BP may have impacted much of the western United States.During the middle Holocene (informally defined in this paper as extending from 8000 to 3000 cal yr BP), magnetic susceptibility values of sediments deposited in Pyramid Lake’s deep basin were much larger than late–Holocene (3000–0 cal yr BP) values, indicating the presence of a shallow lake. In addition, the mean δ18O value of CaCO3 precipitated between 6500 and 3430 cal yr BP was 1.6m less than the mean value of CaCO3 precipitated after 2740 cal yr BP. Numerical calculations indicate that the shift in the δ18O baseline probably resulted from a transition to a wetter (\u3e30%) and cooler (3–5 °C) climate. The existence of a relatively dry and warm middle-Holocene climate in the Truckee River– Pyramid Lake system is generally consistent with archeological, sedimentological, chemical, physical, and biological records from various sites within the Great Basin of the western United States. Two high-resolution Holocene-climate records are now available from the Pyramid and Owens lake basins which suggest that the Holocene was characterized by five climatic intervals. TIC and δ18O records from Owens Lake indicate that the first interval in the early Holocene (11,600–10,000 cal yr BP) was characterized by a drying trend that was interrupted by a brief (200 yr) wet oscillation centered at 10,300 cal yr BP. This was followed by a second early- Holocene interval (10,000–8000 cal yr BP) during which relatively wet conditions prevailed. During the early part of the middle Holocene (8000–6500 cal yr BP), high-amplitude oscillations in TIC in Owens Lake and d18O in Pyramid Lake indicate the presence of shallow lakes in both basins. During the latter part of the middle Holocene (6500–3800 cal yr BP), drought conditions dominated, Owens Lake desiccated, and Lake Tahoe ceased spilling to the Truckee River, causing Pyramid Lake to decline. At the beginning of the late Holocene (~3000 cal yr BP), Lake Tahoe rose to its sill level and Pyramid Lake increased in volume

    Primary agricultural cooperatives in Malawi: Structure, conduct, and performance

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    Primary agricultural cooperatives in Malawi, in contrast to other farmer-level organizations, have legal status and can own assets, borrow money for their operations, and sign contracts, making it easier for them to do business for the profit of their members. Conceptually, such cooperatives enable their member-farmers to achieve economies of scale for their commercial activities. By joining together in a cooperative, members can obtain commercial inputs at lower prices closer to wholesale prices than if they purchased the inputs as individuals. In selling their output, by aggregating their crops and other products into larger lots that the cooperative then negotiates to sell on their behalf, buyers can achieve greater efficiency in buying from them and can be expected to offer a premium over the prices that they would offer farmers selling those products individually. Cooperatives can also serve farmers in providing an important channel for obtaining information and advice to increase their productivity and the profitability of their farming. Moreover, by joining together to achieve common objectives in primary agricultural cooperatives, member-farmers can exercise greater influence on local and national policy issues of concern to them, while also building social cohesion, solidarity, and trust within their communities

    Can cooperatives commercialize farming in Malawi?

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    Smallholder farmers constitute the largest group of economic actors in Malawi and there is increasing recognition that the small scale at which they operate does not offer for most a pathway out of poverty, let alone to prosperity. Increasingly the idea is gaining traction that by joining forces through primary agricultural cooperatives, smallholder farmers across Malawi can reap many of the benefits that larger farmers on commercial estates have been able to realize, such as negotiating better price for agricultural inputs through bulk purchases; negotiating better prices for agricultural outputs through aggregation and storage; adding value to raw agricultural products; accessing professional equipment, such as tractors or irrigation; hiring professional services, such as a farm or business manager; or pooling contiguous pieces of land for more efficient farming. In this brief we summarize the findings of a detailed report (Davis et al., 2022) on research conducted to assess the current status of cooperatives in the country and what project implementers and policymakers can do to enable cooperatives to contribute to increased commercialization and professionalization of smallholder farming in Malawi

    Association of low-activity MAOA allelic variants with violent crime in incarcerated offenders

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    This is the author's final draft. Copyright 2014 ElsevierThe main enzyme for serotonin degradation, monoamine oxidase (MAO) A, has recently emerged as a key biological factor in the predisposition to impulsive aggression. Male carriers of low-activity variants of the main functional polymorphism of the MAOA gene (MAOA-uVNTR) have been shown to exhibit a greater proclivity to engage in violent acts. Thus, we hypothesized that low-activity MAOA-uVNTR alleles may be associated with a higher risk for criminal violence among male offenders. To test this possibility, we analyzed the MAOA-uVNTR variants of violent (n = 49) and non-violent (n = 40) male Caucasian and African-American convicts in a correctional facility. All participants were also tested with the Childhood Trauma Questionnaire (CTQ), Barratt Impulsivity Scale (BIS-11) and Buss-Perry Aggression Questionnaire (BPAQ) to assess their levels of childhood trauma exposure, impulsivity and aggression, respectively. Our results revealed a robust (P < 0.0001) association between low-activity MAOA-uVNTR alleles and violent crime. This association was replicated in the group of Caucasian violent offenders (P < 0.01), but reached only a marginal trend (P = 0.08) in their African American counterparts. While violent crime charges were not associated with CTQ, BIS-11 and BPAQ scores, carriers of low-activity alleles exhibited a mild, yet significant (P < 0.05) increase in BIS-11 total and attentional-impulsiveness scores. In summary, these findings support the role of MAOA gene as a prominent genetic determinant for criminal violence. Further studies are required to confirm these results in larger samples of inmates and evaluate potential interactions between MAOA alleles and environmental vulnerability factors

    Effects of menstrual phase on intake of nicotine, caffeine, and alcohol and nonprescribed drugs in women with late luteal phase dysphoric disorder

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    To investigate the possibility that cigarette smoking and other drug use are affected by menstrual phase in smokers with Late Luteal Phase Dysphoric Disorder (LLPDD), we examined daily diaries rating menstrual symptomatology, smoking, alcohol and nonprescription drug use, and caffeine intake in nine female smokers meeting criteria for LLPDD. Menstrual symptomatology peaked during the premenstrual phase. Smoking, alcohol, and nonprescription drug intake were increased during menses; caffeine intake was unaffected by phase. No systematic intrasubject correlation between symptomatology and smoking was detected. It was concluded that in women with LLPDD, smoking and alcohol and nonprescription drug intake appear to vary as a function of menstrual phase. The lack of intrasubject correlations between symptomatology and intake, and the failure of peak intake to coincide with peak symptomatology, however, indicate that these effects cannot be explained simply as "self-medication" of acute episodes of dysphoric mood.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31910/1/0000863.pd

    Cloud Radiative Forcing at the ARM Climate Research Facility

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    It has been hypothesized that continuous ground-based remote sensing measurements from active and passive remote sensors combined with regular soundings of the atmospheric thermodynamic structure can be combined to describe the effects of clouds on the clear sky radiation fluxes. We critically test that hypothesis in this paper and a companion paper (Part II). Using data collected at the Southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site sponsored by the U.S. Department of Energy, we explore an analysis methodology that results in the characterization of the physical state of the atmospheric profile at time resolutions of five minutes and vertical resolutions of 90 m. The description includes thermodynamics and water vapor profile information derived by merging radiosonde soundings with ground-based data, and continues through specification of the cloud layer occurrence and microphysical and radiative properties derived from retrieval algorithms and parameterizations. The description of the atmospheric physical state includes a calculation of the infrared and clear and cloudy sky solar flux profiles. Validation of the methodology is provided by comparing the calculated fluxes with top of atmosphere (TOA) and surface flux measurements and by comparing the total column optical depths to independently derived estimates. We find over a 1-year period of comparison in overcast uniform skies, that the calculations are strongly correlated to measurements with biases in the flux quantities at the surface and TOA of less than 10% and median fractional errors ranging from 20% to as low as 2%. In the optical depth comparison for uniform overcast skies during the year 2000 where the optical depth varies over 3 orders of magnitude we find a mean positive bias of 46% with a median bias of less than 10% and a 0.89 correlation coefficient. The slope of the linear regression line for the optical depth comparison is 0.86 with a normal deviation of 20% about this line. In addition to a case study where we examine the cloud radiative effects at the TOA, surface and atmosphere by a middle latitude synoptic-scale cyclone, we examine the cloud top pressure and optical depth retrievals of ISCCP and LBTM over a period of 1 year. Using overcast period from the year 2000, we find that the satellite algorithms tend to bias cloud tops into the middle troposphere and underestimate optical depth in high optical depth events (greater than 100) by as much as a factor of 2

    Enabling long-term oceanographic research : changing data practices, information management strategies and informatics

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    Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 55 (2008): 2132-2142, doi:10.1016/j.dsr2.2008.05.009.Interdisciplinary global ocean science requires new ways of thinking about data and data management. With new data policies and growing technological capabilities, datasets of increasing variety and complexity are being made available digitally and data management is coming to be recognized as an integral part of scientific research. To meet the changing expectations of scientists collecting data and of data reuse by others, collaborative strategies involving diverse teams of information professionals are developing. These changes are stimulating the growth of information infrastructures that support multi-scale sampling, data repositories, and data integration. Two examples of oceanographic projects incorporating data management in partnership with science programs are discussed: the Palmer Station Long-Term Ecological Research program (Palmer LTER) and the United States Joint Global Ocean Flux Study (US JGOFS). Lessons learned from a decade of data management within these communities provide an experience base from which to develop information management strategies – short-term and long-term. Ocean Informatics provides one example of a conceptual framework for managing the complexities inherent to sharing oceanographic data. Elements are introduced that address the economies-of-scale and the complexities-of-scale pertinent to a broader vision of information management and scientific research.Support is provided by NSF OPP-0217282, OCE-0405069, HSD-0433369 and Scripps Institution of Oceanography (K.S.Baker) and by NSF OCE-8814310, OCE-0097291, OCE- 0510046 and OCE-0646353 (C.Chandler)

    HMMSplicer: A Tool for Efficient and Sensitive Discovery of Known and Novel Splice Junctions in RNA-Seq Data

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    Background: High-throughput sequencing of an organism’s transcriptome, or RNA-Seq, is a valuable and versatile new strategy for capturing snapshots of gene expression. However, transcriptome sequencing creates a new class of alignment problem: mapping short reads that span exon-exon junctions back to the reference genome, especially in the case where a splice junction is previously unknown. Methodology/Principal Findings: Here we introduce HMMSplicer, an accurate and efficient algorithm for discovering canonical and non-canonical splice junctions in short read datasets. HMMSplicer identifies more splice junctions than currently available algorithms when tested on publicly available A. thaliana, P. falciparum, and H. sapiens datasets without a reduction in specificity. Conclusions/Significance: HMMSplicer was found to perform especially well in compact genomes and on genes with low expression levels, alternative splice isoforms, or non-canonical splice junctions. Because HHMSplicer does not rely on prebuilt gene models, the products of inexact splicing are also detected. For H. sapiens, we find 3.6 % of 39 splice sites and 1.4% of 59 splice sites are inexact, typically differing by 3 bases in either direction. In addition, HMMSplicer provides a score for every predicted junction allowing the user to set a threshold to tune false positive rates depending on the needs of the experiment. HMMSplicer is implemented in Python. Code and documentation are freely available a
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