200 research outputs found

    Agro-environmental project duration and effectiveness in South-east Asia

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    Considerable emphasis has been placed on developing technologies for agricultural sustainability. Many bilateral projects are working to achieve this outcome. A desk review was conducted to study the importance of project duration for the effectiveness of sustainable agricultural projects. Longer-duration projects were successful in addressing more holistic issues than short projects. However, funding agencies tend to fund shorter-duration projects, so projects become progressively shorter. At the same time, the number of projects implemented each year is increasing. Despite the decrease in total development assistance, increases in project numbers, particularly since 1986, appear to be at the cost of project duration. Short project duration was one of the most cited reasons for not completing essential dissemination activities for wider adoption, whereas longer- duration projects were usually considered more successful in addressing more holistic issues. It is difficult to produce tangible outputs from agricultural and soil conservation projects within five years. Considering the slow changes in the system and in agricultural and environmental sustainability, the authors suggest that project developers should be advised to plan for a minimum of 5–10 years, depending on the nature of activities. It is time for funding agencies to reconsider their tendency to fund shorter-duration projects

    Primary Blast Traumatic Brain Injury in the Rat: Relating Diffusion Tensor Imaging and Behavior

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    The incidence of traumatic brain injury (TBI) among military personnel is at its highest point in U.S. history. Experimental animal models of blast have provided a wealth of insight into blast injury. The mechanisms of neurotrauma caused by blast, however, are still under debate. Specifically, it is unclear whether the blast shockwave in the absence of head motion is sufficient to induce brain trauma. In this study, the consequences of blast injury were investigated in a rat model of primary blast TBI. Animals were exposed to blast shockwaves with peak reflected overpressures of either 100 or 450 kPa (39 and 110 kPa incident pressure, respectively) and subsequently underwent a battery of behavioral tests. Diffusion tensor imaging (DTI), a promising method to detect blast injury in humans, was performed on fixed brains to detect and visualize the spatial dependence of blast injury. Blast TBI caused significant deficits in memory function as evidenced by the Morris Water Maze, but limited emotional deficits as evidenced by the Open Field Test and Elevated Plus Maze. Fractional anisotropy, a metric derived from DTI, revealed significant brain abnormalities in blast-exposed animals. A significant relationship between memory deficits and brain microstructure was evident in the hippocampus, consistent with its role in memory function. The results provide fundamental insight into the neurological consequences of blast TBI, including the evolution of injury during the sub-acute phase and the spatially dependent pattern of injury. The relationship between memory dysfunction and microstructural brain abnormalities may provide insight into the persistent cognitive difficulties experienced by soldiers exposed to blast neurotrauma and may be important to guide therapeutic and rehabilitative efforts

    Evidence for Blue Straggler Stars Rejuvenating the Integrated Spectra of Globular Clusters

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    Integrated spectroscopy is the method of choice for deriving the ages of unresolved stellar systems. However, hot stellar evolutionary stages, such as hot horizontal branch stars and blue straggler stars (BSSs), can affect the integrated ages measured using Balmer lines. Such hot, "non-canonical" stars may lead to overestimations of the temperature of the main sequence turn-off, and therefore underestimations of the integrated age of a stellar population. Using an optimized Hbeta index in conjunction with HST/WFPC2 color-magnitude diagrams (CMDs), we show that Galactic globular clusters exhibit a large scatter in their apparent "spectroscopic" ages, which does not correspond to that in their CMD-derived ages. We find for the first time that the specific frequency of BSSs, defined within the same aperture as the integrated spectra, shows a clear correspondence with Hbeta in the sense that, at fixed metallicity, higher BSS ratios lead to younger "apparent" spectroscopic ages. Thus, the specific frequency of BSSs in globular clusters sets a fundamental limit on the accuracy for which spectroscopic ages can be determined for globular clusters, and maybe for other stellar systems like galaxies. The observational implications of this result are discussed.Comment: 5 pages, 2 figures, 1 table. Accepted for publication in ApJ

    Preinjury somatization symptoms contribute to clinical recovery after sport-related concussion

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    OBJECTIVE: To determine the degree to which preinjury and acute postinjury psychosocial and injury-related variables predict symptom duration following sport-related concussion. METHODS: A total of 2,055 high school and collegiate athletes completed preseason evaluations. Concussed athletes (n = 127) repeated assessments serially (<24 hours and days 8, 15, and 45) postinjury. Cox proportional hazard modeling was used to predict concussive symptom duration (in days). Predictors considered included demographic and history variables; baseline psychological, neurocognitive, and balance functioning; acute injury characteristics; and postinjury clinical measures. RESULTS: Preinjury somatic symptom score (Brief Symptom Inventory-18 somatization scale) was the strongest premorbid predictor of symptom duration. Acute (24-hour) postconcussive symptom burden (Sport Concussion Assessment Tool-3 symptom severity) was the best injury-related predictor of recovery. These 2 predictors were moderately correlated (r = 0.51). Path analyses indicated that the relationship between preinjury somatization symptoms and symptom recovery was mediated by postinjury concussive symptoms. CONCLUSIONS: Preinjury somatization symptoms contribute to reported postconcussive symptom recovery via their influence on acute postconcussive symptoms. The findings highlight the relevance of premorbid psychological factors in postconcussive recovery, even in a healthy athlete sample relatively free of psychopathology or medical comorbidities. Future research should elucidate the neurobiopsychosocial mechanisms that explain the role of this individual difference variable in outcome following concussive injury

    Age Differences in Recovery After Sport-Related Concussion: A Comparison of High School and Collegiate Athletes

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    Younger age has been hypothesized to be a risk factor for prolonged recovery after sport-related concussion, yet few studies have directly evaluated age differences in acute recovery

    Prospective, Head-to-Head Study of Three Computerized Neurocognitive Assessment Tools (CNTs): Reliability and Validity for the Assessment of Sport-Related Concussion

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    Abstract Limited data exist comparing the performance of computerized neurocognitive tests (CNTs) for assessing sport-related concussion. We evaluated the reliability and validity of three CNTs—ANAM, Axon Sports/Cogstate Sport, and ImPACT—in a common sample. High school and collegiate athletes completed two CNTs each at baseline. Concussed ( n =165) and matched non-injured control ( n =166) subjects repeated testing within 24 hr and at 8, 15, and 45 days post-injury. Roughly a quarter of each CNT’s indices had stability coefficients ( M =198 day interval) over .70. Group differences in performance were mostly moderate to large at 24 hr and small by day 8. The sensitivity of reliable change indices (RCIs) was best at 24 hr (67.8%, 60.3%, and 47.6% with one or more significant RCIs for ImPACT, Axon, and ANAM, respectively) but diminished to near the false positive rates thereafter. Across time, the CNTs’ sensitivities were highest in those athletes who became asymptomatic within 1 day before neurocognitive testing but was similar to the tests’ false positive rates when including athletes who became asymptomatic several days earlier. Test–retest reliability was similar among these three CNTs and below optimal standards for clinical use on many subtests. Analyses of group effect sizes, discrimination, and sensitivity and specificity suggested that the CNTs may add incrementally (beyond symptom scores) to the identification of clinical impairment within 24 hr of injury or within a short time period after symptom resolution but do not add significant value over symptom assessment later. The rapid clinical recovery course from concussion and modest stability probably jointly contribute to limited signal detection capabilities of neurocognitive tests outside a brief post-injury window. ( JINS , 2016, 22 , 24–37

    Integrating workplace exposure databases for occupational medicine services and epidemiologic studies at a former nuclear weapons facility

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    We outline methods for integrating epidemiologic and industrial hygiene data systems for the purpose of exposure estimation, exposure surveillance, worker notification, and occupational medicine practice. We present examples of these methods from our work at the Rocky Flats Plant?a former nuclear weapons facility that fabricated plutonium triggers for nuclear weapons and is now being decontaminated and decommissioned. The weapons production processes exposed workers to plutonium, gamma photons, neutrons, beryllium, asbestos, and several hazardous chemical agents, including chlorinated hydrocarbons and heavy metals. We developed a job exposure matrix (JEM) for estimating exposures to 10 chemical agents in 20 buildings for 120 different job categories over a production history spanning 34 years. With the JEM, we estimated lifetime chemical exposures for about 12,000 of the 16,000 former production workers. We show how the JEM database is used to estimate cumulative exposures over different time periods for epidemiological studies and to provide notification and determine eligibility for a medical screening program developed for former workers. We designed an industrial hygiene data system for maintaining exposure data for current cleanup workers. We describe how this system can be used for exposure surveillance and linked with the JEM and databases on radiation doses to develop lifetime exposure histories and to determine appropriate medical monitoring tests for current cleanup workers. We also present time-line-based graphical methods for reviewing and correcting exposure estimates and reporting them to individual workers

    The Association Between Persistent White-Matter Abnormalities and Repeat Injury After Sport-Related Concussion

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    Objective: A recent systematic review determined that the physiological effects of concussion may persist beyond clinical recovery. Preclinical models suggest that ongoing physiological effects are accompanied by increased cerebral vulnerability that is associated with risk for subsequent, more severe injury. This study examined the association between signal alterations on diffusion tensor imaging following clinical recovery of sport-related concussion in athletes with and without a subsequent second concussion. Methods: Average mean diffusivity (MD) was calculated in a region of interest (ROI) in which concussed athletes (n = 82) showed significantly elevated MD acutely after injury (<48 h), at an asymptomatic time point, 7 days post-return to play (RTP), and 6 months relative to controls (n = 69). The relationship between MD in the identified ROI and likelihood of sustaining a subsequent concussion over a 1-year period was examined with a binary logistic regression (re-injured, yes/no). Results: Eleven of 82 concussed athletes (13.4%) sustained a second concussion within 12 months of initial injury. Mean MD at 7 days post-RTP was significantly higher in those athletes who went on to sustain a repeat concussion within 1 year of initial injury than those who did not (p = 0.048; d = 0.75). In this underpowered sample, the relationship between MD at 7 days post-RTP and likelihood of sustaining a secondary injury approached significance [χ2 (1) = 4.17, p = 0.057; B = 0.03, SE = 0.017; OR = 1.03, CI = 0.99, 1.07]. Conclusions: These preliminary findings raise the hypothesis that persistent signal abnormalities in diffusion imaging metrics at RTP following concussion may be predictive of a repeat concussion. This may reflect a window of cerebral vulnerability or increased susceptibility following concussion, though understanding the clinical significance of these findings requires further study
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