61 research outputs found

    Performance Analysis of Multi-Echelon Inventory Systems.

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    A two-echelon inventory and distribution system consisting of a centralized warehouse and N stores is considered in this paper. The inventories of the warehouse as well as the stores are controlled by periodic review (s,S) ordering policies. The expected levels of capital investment, storage space needs, capacity requirements for delivery vehicles, and reliable customer service are issues of great importance to practitioners when considering the introduction of a central warehouse and transportation system. Helmut Schneider, Dan Rinks, and Peter Kelle have developed a methodology that has been shown to provide approximately optimal (s,S) policies under various demand conditions, and are easy to handle computationally. The approximations of Schneider et al., are used to generate ordering policies for the two-echelon system in order to observe the behavior of the aggregate inventories generated by the (s,S) policies using computer simulation. The simulation results are used to evaluate the accuracy of the analytic models in predicting the aggregate inventory behavior, and simple computational formulas are proposed to calculate confidence limits for aggregate inventory levels and for shipping volumes and weights

    Chronic widespread pain after motor vehicle collision typically occurs through immediate development and nonrecovery: results of an emergency department-based cohort study

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    Motor vehicle collision (MVC) can trigger chronic widespread pain (CWP) development in vulnerable individuals. Whether such CWP typically develops via the evolution of pain from regional to widespread or via the early development of widespread pain with non-recovery is currently unknown. We evaluated the trajectory of CWP development (American College of Rheumatology criteria) among 948 European-American individuals who presented to the emergency department (ED) for care in the early aftermath of MVC. Pain extent was assessed in the ED and 6 weeks, 6 months, and 1 year after MVC on 100%, 91%, 89%, and 91% of participants, respectively. Individuals who reported prior CWP at the time of ED evaluation (n = 53) were excluded. Trajectory modeling identified a two-group solution as optimal, with the Bayes Factor value (138) indicating strong model selection. Linear solution plots supported a non-recovery model. While the number of body regions with pain in the non-CWP group steadily declined, the number of body regions with pain in the CWP trajectory group (192/895, 22%) remained relatively constant over time. These data support the hypothesis that individuals who develop CWP after MVC develop widespread pain in the early aftermath of MVC which does not remit

    Using emergency department-based inception cohorts to determine genetic characteristics associated with long term patient outcomes after motor vehicle collision: Methodology of the CRASH study

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    <p>Abstract</p> <p>Background</p> <p>Persistent musculoskeletal pain and psychological sequelae following minor motor vehicle collision (MVC) are common problems with a large economic cost. Prospective studies of pain following MVC have demonstrated that demographic characteristics, including female gender and low education level, and psychological characteristics, including high pre-collision anxiety, are independent predictors of persistent pain. These results have contributed to the psychological and social components of a biopsychosocial model of post-MVC pain pathogenesis, but the biological contributors to the model remain poorly defined. Recent experimental studies indicate that genetic variations in adrenergic system function influence the vulnerability to post-traumatic pain, but no studies have examined the contribution of genetic factors to existing predictive models of vulnerability to persistent pain.</p> <p>Methods/Design</p> <p>The Project CRASH study is a federally supported, multicenter, prospective study designed to determine whether variations in genes affecting synaptic catecholamine levels and alpha and beta adrenergic receptor function augment social and psychological factors in a predictive model of persistent musculoskeletal pain and posttraumatic stress disorder (PTSD) following minor MVC. The Project CRASH study will assess pain, pain interference and PTSD symptoms at 6 weeks, 6 months, and 1 year in approximately 1,000 patients enrolled from 8 Emergency Departments in four states with no-fault accident laws.</p> <p>Discussion</p> <p>The results from this study will provide insights into the pathophysiology of persistent pain and PTSD following MVC and may serve to improve the ability of clinicians and researchers to identify individuals at high risk for adverse outcomes following minor MVC.</p

    Variations in Institutional Review Board reviews of a multi-center, Emergency Department-based genetic research protocol

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    AbstractIntroductionIn the United States, institutional review boards (IRBs) oversee the scientific, ethical, and regulatory aspects of research conducted on human subjects. Institutional variations in the interpretation and application of federal and local regulations concerning genetic testing can have significant impact on the implementation of such studies.ObjectiveWe assessed variability in IRB review of a multi-center Emergency Department-based study examining genotypic and phenotypic predictors of pain and psychological outcomes after minor motor vehicle collision (Project CRASH). This is one of the first multi-center genetic research protocols based solely in the Emergency Department (ED).MethodsWe performed an observational study of sites participating in Project CRASH. We collected IRB information and correspondence from each site. We collected data that included information regarding institution demographics, original IRB application characteristics, subsequent IRB correspondence, and time interval between submission and approval. Descriptive statistics were used in analysis.ResultsAll sites that initially agreed to participate in Project CRASH also participated in this study (n = 7). The time interval in receiving IRB approval varied between 20-760 days (median 105, IQR 21-225). One site appeared to be an outlier (760 days). The most commonly requested changes were changes to the consent form.ConclusionInstitutional interpretation of regulations regarding our ED-based genetic study was highly variable. Although the majority of our results are consistent with other similar published studies, the mean time interval for approval for this genetic study is far greater than other reported studies

    Crop Updates 2006 - Cadoux and Calingiri

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    This session covers nine papers from different authors Performance of oaten hay varieties in Western Australian environments, Raj Malik and Kellie Winfield, Department of Agriculture Performance of dwarf potential milling varieties in Western Australian environments, Raj Malik and Kellie Winfield, Department of Agriculture 2006 Seasonal outlook, David Stephens, Michael Meuleners and Kari-Lee Falconer, Department of Agriculture Matching nitrogen supply to crop demand in high rainfall cropping, Bill Bowden, Narelle Simpson Department of Agriculture An overview of the potential for a Biofuels Industry in Western Australia, Anne Wilkins and Nathan Hancock, Department of Agriculture IWM performs over 5 years in 33 focus paddocks, Peter Newman and Glen Adam, Department of Agriculture Analysis of a wheat-pasture rotation in the 330mm annual rainfall zone using the STEP model, Andrew Blake and Caroline Peak Department of Agriculture What lies beneath? – Understanding constraints to productivity below the soil surface, Stephen Davies and Chris Gazey Department of agriculture, Bob Gilkes, Dan Evans and Tania Liaghati, University of Western Australia Managing the Unmanageable, Bill Bowden, Department of Agricultur

    Incidence and Predictors of Acute Psychological Distress and Dissociation After Motor Vehicle Collision: A Cross-Sectional Study

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    The authors examined the incidence and predictors of peritraumatic distress and dissociation after one of the most common forms of civilian trauma exposure: motor vehicle collision (MVC)

    Opioid Receptor Gene A118 G Variants and Persistent Pain Symptoms Among Men and Women Experiencing Motor Vehicle Collision

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    AbstractThe μ-opioid receptor 1 (OPRM1) binds endogenous opioids. Increasing evidence suggests that endogenous OPRM1 agonists released at the time of trauma may contribute to the development of posttraumatic musculoskeletal pain (MSP). In this prospective observational study, we evaluated the hypothesis that individuals with an AG or GG genotype at the OPRM1 A118 G allele, which results in a reduced response to opioids, would have less severe MSP 6 weeks after motor vehicle collision (MVC). Based on previous evidence, we hypothesized that this effect would be sex-dependent and most pronounced among women with substantial peritraumatic distress. European American men and women ≥18 years of age presenting to the emergency department after MVC and discharged to home after evaluation (N = 948) were enrolled. Assessments included genotyping and 6-week evaluation of overall MSP severity (0–10 numeric rating scale). In linear regression modeling, a significant A118 G Allele × Sex interaction was observed: an AG/GG genotype predicted reduced MSP severity among women with substantial peritraumatic distress (β = –.925, P = .014) but not among all women. In contrast, men with an AG/GG genotype experienced increased MSP severity at 6 weeks (β = .827, P = .019). Further studies are needed to understand the biologic mechanisms mediating observed sex differences in A118 G effects.PerspectiveThese results suggest a sex-dependent mechanism by which an emotional response to trauma (distress) contributes to a biologic mechanism (endogenous opioid release) that increases MSP in the weeks after stress exposure. These results also support the hypothesis that endogenous opioids influence pain outcomes differently in men and women

    Association of Epidemiologic Factors and Genetic Variants Influencing Hypothalamic-Pituitary-Adrenocortical Axis Function With Postconcussive Symptoms After Minor Motor Vehicle Collision

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    To determine the influence of epidemiologic factors and the influence of genetic variants affecting FKBP5, a protein known to modulate hypothalamic-pituitary-adrenocortical (HPA) axis function, on the severity of somatic symptoms commonly termed “post-concussive” six and twelve months after motor-vehicle collision (MVC)

    Pain, distress, and anticipated recovery for older versus younger emergency department patients after motor vehicle collision

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    Abstract Background Motor vehicle collisions (MVCs) are the second most common injury mechanism resulting in emergency department (ED) visits by older adults. MVCs result in substantial pain and psychological distress among younger individuals, but little is known about the occurrence of these symptoms in older individuals. We describe the frequency of and characteristics associated with pain, distress, and anticipated time for physical and emotional recovery for older adults presenting to the ED after MVC in comparison to younger adults. Methods In-person interviews were conducted for adults presenting to one of eight EDs after MVC without an obvious fracture or injury requiring admission as part of two prospective studies. Pain severity was assessed using a 0–10 verbal scale. Distress was assessed using the Peritraumatic Distress Inventory (range 0–52). Patients were asked to estimate their expected time for physical and emotional recovery; these responses were dichotomized to <30 or ≥30 days. ED pain and distress and associations between patient and collision characteristics and ED pain and distress were examined for patients age 65 years and older and patients age 18 to 64. Results Older (n = 96) and younger (n = 943) adults had the same mean pain scores (5.5, SD 2.5 vs. 5.5, SD 2.4). Distress scores were lower in older than in younger adults (15.5, SD 9 vs. 19.2, SD 10). A higher percentage of older adults than younger adults had an anticipated time to physical recovery ≥30 days (41%, 95% confidence interval [CI] 28%-55% vs. 11%, 95% CI 9%-13%). Similarly, older adults were more likely to have an anticipated time for emotional recovery ≥30 days (45%, 95% CI 35%-55% vs. 17%, 95% CI 15%-20%). Older adults were less likely than younger adults to have moderate or severe neck pain (score ≥4) (25%, 95% CI 23% to 41% vs. 54%, 95% CI 48% to 60%) or back pain (31%, 95% CI 23% to 46% vs. 56%, 95% CI 51 to 62%) but more likely to have moderate or severe chest pain (42%, 95% CI 32% to 50% vs. 20%, 95% CI 16 to 23%). Pre-MVC depressive symptoms and pain catastrophizing were positively associated with pain and distress in both older and younger adults. Conclusions In our cohort, older adults who presented to the ED after MVC experienced similar pain severity as younger patients and less distress but were more likely to estimate their times for physical and emotional recovery to be 30 days or more. Increased emergency provider awareness of acute pain and distress symptoms among older patients experiencing MVC may improve outcomes for these patients

    Genetic Polymorphisms in the Dopamine Receptor 2 Predict Acute Pain Severity after Motor Vehicle Collision

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    Dopaminergic signaling is implicated in nociceptive pathways. These effects are mediated largely through dopamine receptors and modulated in part by dopamine transporters. This study tests the hypothesis that genetic variants in the genes encoding dopamine receptor 2 (DRD2) and the dopamine active transporter (SLC6A3) influence acute pain severity after motor vehicle collision (MVC)
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