1,859 research outputs found

    Integrating the SAP R/3 System into an MIS Program

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    In this tutorial, the authors share their experience with integrating the SAP R/3 System into their curriculum so that an attendee can walk away knowing how to approach the tasks at his or her university. The authors are part of a team of faculty whose ultimate objective is to develop a cross-functional business school curriculum. An overview of the business plan is presented, some details regarding systems administration is provided, and the majority of the time is spent on identifying opportunities for enriching an MIS program. This paper does not address curriculum content issues but provides information on how a commercial ERP system (i.e., the SAP R/3 System) can be effectively utilized in an MIS program. The opinions expressed here are solely those of the authors

    Latitude and Longing: Cartography of Desire

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    pages 91-9

    Regional variations in ex-vivo diffusion tensor anisotropy are associated with cardiomyocyte remodeling in rats after left ventricular pressure overload

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    Background Pressure overload left ventricular (LV) hypertrophy is characterized by increased cardiomyocyte width and ventricle wall thickness, however the regional variation of this remodeling is unclear. Cardiovascular magnetic resonance (CMR) diffusion tensor imaging (DTI) may provide a non-invasive, comprehensive, and geometrically accurate method to detect regional differences in structural remodeling in hypertrophy. We hypothesized that DTI parameters, such as fractional and planar anisotropy, would reflect myocyte remodeling due to pressure overload in a regionally-dependent manner. Methods We investigated the regional distributions of myocyte remodeling in rats with or without transverse aortic constriction (TAC) via direct measurement of myocyte dimensions with confocal imaging of thick tissue sections, and correlated myocyte cross-sectional area and other geometric features with parameters of diffusivity from ex-vivo DTI in the same regions of the same hearts. Results We observed regional differences in several parameters from DTI between TAC hearts and SHAM controls. Consistent with previous studies, helix angles from DTI correlated strongly with those measured directly from histological sections (p < 0.001, R2 = 0.71). There was a transmural gradient in myocyte cross-sectional area in SHAM hearts that was diminished in the TAC group. We also found several regions of significantly altered DTI parameters in TAC LV compared to SHAM, especially in myocyte sheet angle dispersion and planar anisotropy. Among others, these parameters correlated significantly with directly measured myocyte aspect ratios. Conclusions These results show that structural remodeling in pressure overload LV hypertrophy is regionally heterogeneous, especially transmurally, with a greater degree of remodeling in the sub-endocardium compared to the sub-epicardium. Additionally, several parameters derived from DTI correlated significantly with measurements of myocyte geometry from direct measurement in histological sections. We suggest that DTI may provide a non-invasive, comprehensive method to detect regional structural myocyte LV remodeling during disease

    Urban agriculture: a global analysis of the space constraint to meet urban vegetable demand

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    Urban agriculture (UA) has been drawing a lot of attention recently for several reasons: the majority of the world population has shifted from living in rural to urban areas; the environmental impact of agriculture is a matter of rising concern; and food insecurity, especially the accessibility of food, remains a major challenge. UA has often been proposed as a solution to some of these issues, for example by producing food in places where population density is highest, reducing transportation costs, connecting people directly to food systems and using urban areas efficiently. However, to date no study has examined how much food could actually be produced in urban areas at the global scale. Here we use a simple approach, based on different global-scale datasets, to assess to what extent UA is constrained by the existing amount of urban space. Our results suggest that UA would require roughly one third of the total global urban area to meet the global vegetable consumption of urban dwellers. This estimate does not consider how much urban area may actually be suitable and available for UA, which likely varies substantially around the world and according to the type of UA performed. Further, this global average value masks variations of more than two orders of magnitude among individual countries. The variations in the space required across countries derive mostly from variations in urban population density, and much less from variations in yields or per capita consumption. Overall, the space required is regrettably the highest where UA is most needed, i.e., in more food insecure countries. We also show that smaller urban clusters (i.e., <100 km2 each) together represent about two thirds of the global urban extent; thus UA discourse and policies should not focus on large cities exclusively, but should also target smaller urban areas that offer the greatest potential in terms of physical space

    Adiposity, Physical Function, and Their Associations With Insulin Resistance, Inflammation, and Adipokines in CKD

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    Rationale & Objectives: Adiposity and physical fitness levels are major drivers of cardiometabolic risk, but these relationships have not been well-characterized in chronic kidney disease (CKD). We examined the associations of visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), intrahepatic fat, and physical function with inflammation, insulin resistance, and adipokine levels in patients with CKD. Study Design: Prospective cohort study. Setting & Participants: Participants with stages 3-5 CKD not receiving maintenance dialysis, followed up at one of 8 clinical sites in the Chronic Renal Insufficiency Cohort (CRIC) Study, and who underwent magnetic resonance imaging of the abdomen at an annual CRIC Study visit (n = 419). Predictors: VAT volume, SAT volume, intrahepatic fat, body mass index, waist circumference, and time taken to complete the 400-m walk test (physical function). Outcomes: Markers of inflammation (interleukin 1β [IL-1β], IL-6, tumor necrosis factor receptor 1 [TNFR1], and TNFR2), insulin resistance (homeostasis model assessment of insulin resistance), and adipokine levels (adiponectin, total and high molecular weight, resistin, and leptin). Analytical Approach: Multivariable linear regression of VAT and SAT volume, intrahepatic fat, and physical function with individual markers (log-transformed values), adjusting for relevant covariates. Results: Mean age of the study population was 64.3 years; 41% were women, and mean estimated glomerular filtration rate was 53.2 ± 14.6 (SD) mL/min/1.73 m2. More than 85% were overweight or obese, and 40% had diabetes. Higher VAT volume, SAT volume, and liver proton density fat fraction were associated with lower levels of total and high-molecular-weight adiponectin, higher levels of leptin and insulin resistance, and lower high-density lipoprotein cholesterol and higher serum triglyceride levels. A slower 400-m walk time was associated only with higher levels of leptin, total adiponectin, plasma IL-6, and TNFR1 and did not modify the associations between fat measures and cardiometabolic risk factors. Limitations: Lack of longitudinal data and dietary details. Conclusions: Various measures of adiposity are associated with cardiometabolic risk factors. Physical function was also associated with the cardiometabolic risk factors studied and does not modify associations between fat measures and cardiometabolic risk factors. Longitudinal studies of the relationship between body fat and aerobic fitness with cardiovascular and kidney disease progression are warranted

    Evaluation of honey bee larvae data: sensitivity to PPPs and impact analysis of EFSA Bee GD

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    In addition to other assessments, the EFSA bee guidance document (2013) requires the risk assessment of plant protection products on honey bee larvae. At the time the EFSA GD was finalized, no data on honey bee larvae were available due to absence of suitable methods. That is why in 2013 the European Crop Protection Association (ECPA) perfomed an impact analysis of the new EFSA risk assessment, using extrapolated endpoints derived from acute oral honey bee endpoints. Today, a number of honey bee larvae toxicity studies (138 active substances or formulated products) have been conducted according to the newly developed testing methods for single exposure (OECD TG 237) repeated exposure studies until the end of the larval development (D7/D8) and repeated exposure testing (OECD GD 239) until adult hatch (D22). These experimental data have been used to determine the ‘pass rates’ for 215 worst case uses (72 fungicide spray and solid uses, 91 herbicide spray uses, incl. 8 PGR uses and in total 52 insecticide spray and solid uses, incl. 2 nematicide and 3 IGR uses) according to the EFSA Bee GD and to compare with the original ECPA impact analysis. As standardized test methods for non- Apis bees larvae were not available, risk assessment according to EFSA for bumblebees and solitary bees based on the honey bee endpoint as surrogate corrected by a safety factor of 10. Morevoer, the sensitivity of the NOEDs at D8 and D22 in repeated exposure (D 22) studies were analysed. Overall, the toxicity of fungicides and herbicides to honey bee larvae (expressed as means and medians of NOED and LD50 values) was moderate to low, while insecticides as expected displayed stronger toxicity. Moreover, the endpoints for herbicides were on average a factor of 2 higher than fungicides which ranges within the normal biological variability (factor of 3). In addition, it is unclear, if the difference is related to a slightly higher toxicity or other factors like different physical chemical properties (e.g. lower solubility). For insecticides, toxicity was about 125 (based on medians) and 6 to 8 (based on means) times higher than herbicides. In the screening risk assessment according to EFSA Bee GD the majority of fungicide (83.3%) and herbicide (95.6%) uses passed the risk assessment for larvae; whereas, for all insecticide uses thr pass rate was about 29%. In the Tier 1 risk assessment, these pass rates slightly increased and were even higher in the ‘treated crop’ and ‘weed in the field’ scenarios for fungicide and herbicide uses, almost being 100%. Pass rates for insecticide uses did not improve very much and amounted to be about 42% for both scenarios. When basing the risk assessment of bumblebee and solitary bee larvae on 1/10th of the honey bee larval endpoint, the majority of active substances and their respective products will fail the screening (overall about 96%) and Tier 1 risk assessment (overall about 90%). Alternative risk assessment approaches proposed by ECPA (e.g. following the EPPO approach; ECPA Option 1 using refinement options and more representative assumptions) or comparing an assummed exposure concentration to the NOEC (ECPA Option 2) led to a slight increase (Option 1) or even no differences in the pass rates (Option 2a) compared to EFSA Tier 1 risk assessment. Thus both, the standard risk assessment according to the EFSA Bee GD as well as the alternative ECPA Option 1 and 2 result in a clear distinction between products with high toxicity (insecticides) vs. non-toxic products (herbicides and fungicides) for the honey bee risk assessment. The sensitivity analysis of repeated exposure studies according OECD GD 239 indicated that in most cases toxicity did not increase during the pupation period between D8 and D22. Thus, the larval growing period between D3 and D8 represents the most sensitive period of the pre-imaginal development.In addition to other assessments, the EFSA bee guidance document (2013) requires the risk assessment of plant protection products on honey bee larvae. At the time the EFSA GD was finalized, no data on honey bee larvae were available due to absence of suitable methods. That is why in 2013 the European Crop Protection Association (ECPA) perfomed an impact analysis of the new EFSA risk assessment, using extrapolated endpoints derived from acute oral honey bee endpoints. Today, a number of honey bee larvae toxicity studies (138 active substances or formulated products) have been conducted according to the newly developed testing methods for single exposure (OECD TG 237) repeated exposure studies until the end of the larval development (D7/D8) and repeated exposure testing (OECD GD 239) until adult hatch (D22). These experimental data have been used to determine the ‘pass rates’ for 215 worst case uses (72 fungicide spray and solid uses, 91 herbicide spray uses, incl. 8 PGR uses and in total 52 insecticide spray and solid uses, incl. 2 nematicide and 3 IGR uses) according to the EFSA Bee GD and to compare with the original ECPA impact analysis. As standardized test methods for non- Apis bees larvae were not available, risk assessment according to EFSA for bumblebees and solitary bees based on the honey bee endpoint as surrogate corrected by a safety factor of 10. Morevoer, the sensitivity of the NOEDs at D8 and D22 in repeated exposure (D 22) studies were analysed. Overall, the toxicity of fungicides and herbicides to honey bee larvae (expressed as means and medians of NOED and LD50 values) was moderate to low, while insecticides as expected displayed stronger toxicity. Moreover, the endpoints for herbicides were on average a factor of 2 higher than fungicides which ranges within the normal biological variability (factor of 3). In addition, it is unclear, if the difference is related to a slightly higher toxicity or other factors like different physical chemical properties (e.g. lower solubility). For insecticides, toxicity was about 125 (based on medians) and 6 to 8 (based on means) times higher than herbicides. In the screening risk assessment according to EFSA Bee GD the majority of fungicide (83.3%) and herbicide (95.6%) uses passed the risk assessment for larvae; whereas, for all insecticide uses thr pass rate was about 29%. In the Tier 1 risk assessment, these pass rates slightly increased and were even higher in the ‘treated crop’ and ‘weed in the field’ scenarios for fungicide and herbicide uses, almost being 100%. Pass rates for insecticide uses did not improve very much and amounted to be about 42% for both scenarios. When basing the risk assessment of bumblebee and solitary bee larvae on 1/10th of the honey bee larval endpoint, the majority of active substances and their respective products will fail the screening (overall about 96%) and Tier 1 risk assessment (overall about 90%). Alternative risk assessment approaches proposed by ECPA (e.g. following the EPPO approach; ECPA Option 1 using refinement options and more representative assumptions) or comparing an assummed exposure concentration to the NOEC (ECPA Option 2) led to a slight increase (Option 1) or even no differences in the pass rates (Option 2a) compared to EFSA Tier 1 risk assessment. Thus both, the standard risk assessment according to the EFSA Bee GD as well as the alternative ECPA Option 1 and 2 result in a clear distinction between products with high toxicity (insecticides) vs. non-toxic products (herbicides and fungicides) for the honey bee risk assessment. The sensitivity analysis of repeated exposure studies according OECD GD 239 indicated that in most cases toxicity did not increase during the pupation period between D8 and D22. Thus, the larval growing period between D3 and D8 represents the most sensitive period of the pre-imaginal development

    TEMPERATURE-AND DEFORMATION-DEPENDENT STRUCTURAL CHARACTERIZATION OF SEMI- CRYSTALLINE POLYMERS BY X-RAY SCATTERING

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    ABSTRACT The special mechanical behaviour of semi-crystalline materials is caused by the temperaturedependent interaction between the crystalline and the amorphous phase with their specific mechanical properties. Thereby, the crystalline phase has higher strength and stiffness, it fails mainly under shear stress. The amorphous phase is tough above the glass transition with steadily decreasing strength with increasing temperature. Crazing may appear during. Under the complex load between the crystallites the amorphous phase tends to cavitation if the internal strength is too low with respect to the external load. This general behaviour was investigated and presented in the past by several different groups [1-2]. Recent investigations by synchrotron x-ray scattering enabled a highly time-and strain-resolved as well as temperature dependent investigation of structural changes during deformation. While wide angle diffraction enables a detailed characterization of the crystallites with respect to their orientation and deformation small angle scattering enables information about the size of the different phases and cavitation. Therefore the SAXS patterns were processed to estimate corddistribution-functions according to the procedures developed by Stribeck for samples with fiber symmetry [3]. The behaviour of different semi-crystalline polymers will be presented and compared with the behaviour of pure amorphous materials. A special attention will be turned on the structural events with respect to the stress-strain-curve. Some micrographs confirm the structural units, which were discussed on the basis of the x-ray pattern
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