179 research outputs found

    Time out of mind: Subben's checklist revisited: A partial description of the development of quantitative OR papers over a period of 25 years

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    This short paper aims to investigate some of the historical developments of one classic, well-cited and highly esteemed scientific journal in the domain of quantitative operations research - namely the INFORMS journal Operations Research - over a period of 25 years between 1981 and 2006. As such this paper, and the journal in question, represents one representative attempt to analyze - for the purpose of possible future generalization - how research production has evolved, and evolves, over time. Among the general developments that we think we can trace are that (a) the historical overviews (i.e., literature surveys) in the articles, as well as the list of references, somewhat counter-intuitively shrink over time, while (b) the motivating and modelling parts grow. We also attempt to characterize - in some detail - the appearance and character, over time, of the most cited, as well as the least cited, papers over the years studied. In particular, we find that many of the least cited papers are quite imbalanced. For example, some of them include one main section only, and the least cited papers also have shorter reference lists. We also analyse the articles' utilization of important buzz words representing the constitutive parts of an OR journal paper, based on Subben's checklist (Larsson and Patriksson, 2014, 2016). Based on a word count of these buzz words we conclude through a citation study, utilizing a collection of particularly highly or little cited papers, that there is a quite strong positive correlation between a journal paper being highly cited and its degree of utilization of this checklist

    Off-Road and On-Road Driving Assessments Methods, What Do They Say? A Clinical Sample

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    Driving assessments are carried out in various ways, and diverse methods and tests are used. The British Stroke Driver Screening Assessment (SDSA) is a cognitive test, developed to evaluate driving fitness in stroke patients. For Sweden, Denmark and Norway, there is a Nordic version, the Nordic Stroke Driver Screening Assessment (NorSDSA). This cognitive test has become commonly used by driving assessors and is sometimes the only test used to evaluate driving fitness regardless of a client’s diagnoses. The objective of the study was thus to compare the off-road NorSDSA test outcome, expressed as a global pass or fail result, with an on-road driving test outcome. The results showed that 52 out of 63 patients were correctly classified in the drivers-fail group and 24 of 57 in the pass group. In total, 63% were correctly classified, (sensitivity 42% and specificity 83%). The NorSDSA is thus not a valid predictor for pass or fail on the on-road test. However, only a few neuropsychological tests are made for driving assessments. The NorSDSA is one of them, but driving assessors should know its apparent limitations. The recommendation is thus not to solely rely on the NorSDSA to assess fitness to drive

    Effects on Metabolic Health after a 1-Year-Lifestyle Intervention in Overweight and Obese Children: A Randomized Controlled Trial

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    Objective. To evaluate the effect of a family-based intervention on anthropometric and metabolic markers in overweight and obese children. Methods. Overweight or obese 8–12 years olds (n = 93) were randomized into intervention or control groups. The intervention group participated in a program aiming for lifestyle changes regarding food habits and physical activity. Anthropometric measures and venous blood samples were collected from all children at baseline and after 1 year. Results. BMI z-scores decreased in both groups, 0.22 (P = 0.002) and 0.23 (P = 0.003) in intervention and control group, respectively, during the 1-year study, but there was no difference in BMI between the groups at 1-year measurement (P = 0.338). After 1 year, there was a significant difference in waist circumference, waist/hip ratio, and apolipoprotein B/A1 ratio between intervention and control group. Conclusions. The intervention had limited effects on anthropometrics and metabolic markers, which emphasizes the need of preventing childhood overweight and obesity

    Effects on Metabolic Health after a 1-Year-Lifestyle Intervention in Overweight and Obese Children: A Randomized Controlled Trial

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    Objective. To evaluate the effect of a family-based intervention on anthropometric and metabolic markers in overweight and obese children. Methods. Overweight or obese 8-12 years olds (n = 93) were randomized into intervention or control groups. The intervention group participated in a program aiming for lifestyle changes regarding food habits and physical activity. Anthropometric measures and venous blood samples were collected from all children at baseline and after 1 year. Results. BMI z-scores decreased in both groups, 0.22 (P = 0.002) and 0.23 (P = 0.003) in intervention and control group, respectively, during the 1-year study, but there was no difference in BMI between the groups at 1-year measurement (P = 0.338). After 1 year, there was a significant difference in waist circumference, waist/hip ratio, and apolipoprotein B/A1 ratio between intervention and control group. Conclusions. The intervention had limited effects on anthropometrics and metabolic markers, which emphasizes the need of preventing childhood overweight and obesity

    Impacts of direct payments – lessons for CAP post-2020 from a quantitative analysis

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    In this report we aim to analyse the economic and environmental impacts of Pillar I direct payments, and to demonstrate alternative instruments that are better suited to achieve CAP objectives. The instruments—a targeted payment to land at risk of abandonment and a tax on mineral fertilisers—were selected on the basis of the Polluter Pays and Provider Gets Principles. We do this using two state‐of‐the‐art agricultural economic simulation models. The first model, CAPRI, is used to quantify the large‐scale or aggregate impacts for individual countries, the EU and the world. The other model, AgriPoliS, is used to quantify the fine‐scale or farm and field level impacts in a selection of contrasting agricultural regions, to consider the potential influence of the large spatial variability in agricultural and environmental conditions across the EU. The results show that direct payments are keeping more farms in the sector and more land in agricultural use than would otherwise be the case, and thus avoiding land abandonment, principally in marginal regions. Particularly the area of grassland is substantially higher, because it is generally less productive than arable land and hence more dependent on direct payments for keeping it in agricultural use. The magnitudes of the impacts of direct payments on land use therefore vary strongly across regions due to spatial variability in productivity: marginal regions with large areas of less productive land are heavily influenced by direct payments, while regions with large areas of relatively productive land are hardly affected, because this land would be farmed in any case. By keeping more farmers in the sector longer, direct payments are slowing structural change, which can hamper agricultural development. However the potential benefits of faster structural change vary considerably among our study regions. In relatively productive regions direct payments are hindering development, because too many farmers are staying in the sector and preventing the consolidation of land in larger farms, which would improve their competitiveness and increase farm profits. On the contrary, the mass departure of farms that is currently avoided, will not lead to the same general benefits in marginal regions. Instead of freed land being absorbed by remaining farms, large areas of relatively unproductive land are abandoned without payments. This land is unprofitable to maintain in agricultural land use, even if integrated into larger farms, because current market prices are too low to motivate farming it. Consequently direct payments pose a serious goal conflict: the avoidance of land abandonment on the one hand, which can have negative impacts on public goods, and restricting agricultural development on the other hand. Once again this goal conflict is rooted in the spatial variability of agricultural conditions in the EU. Maintaining extensively managed farmland, particularly semi‐natural pastures, is central for conservation of biodiversity and preservation of the cultural landscape. Therefore direct payments are contributing to the provisioning of these public goods, but principally in marginal areas. Further, abandonment of land can reduce its agricultural productivity due to erosion or afforestation. Thus, direct payments are contributing to food security by preserving the productive potential of land for the future, but only marginal land since relatively productive land is farmed in any case. Production of agricultural commodities is affected to a lesser degree by direct payments than land use per se. Nevertheless, food exports from the EU are higher and imports lower as a consequence of direct payments. However, the additional supply generated by direct payments also lowers output prices, which reduces the profitability of commodity production; thereby partially offsetting the additional revenues from direct payments. The higher agricultural output brought about by direct payments causes higher levels of environmentally damaging greenhouse‐gas emissions, nutrient surpluses and pesticide use. The higher greenhouse‐gas emissions for the EU are, to some extent, moderated by lower emissions in the rest of the world. Nevertheless, the net effect of direct payments is higher global emissions of greenhouse gases. The environmental impacts of higher nutrient surpluses and pesticide inputs are less conclusive, since these depend also on spatial factors, i.e., where the emissions occur. Although EU‐scale and regional emissions are higher due to direct payments, agricultural production is less intensive generally, on account of the lower output prices. Analysing the net effects of these two opposing forces requires additional biophysical modelling at relevant spatial scales, such as watersheds or landscapes, which is beyond the scope of this study. Pillar I direct payments generate a significant transfer of income to farmers and land owners who are not necessarily farmers; 40 billion euro annually. Of this transfer a substantial proportion goes to farmers in relatively productive regions and, further, to a minority of farmers that need them least. In relatively productive regions payments are not needed for continued agricultural production and preservation of farmland, but instead rather fuel higher land and rental prices, which hampers structural change. On the contrary, the need for support is greatest in marginal regions, because some form of payment to marginal land is needed to avoid its abandonment and the loss of associated public goods. Finally, the direct payments even come at the cost of lower market returns for farmers due to slower structural change (smaller and less competitive farms) and lower output prices (due to greater EU output). On the other hand the lower output prices lead to somewhat lower food prices, but at the greater cost of financing the direct payments. Our main conclusion is that Pillar I direct payments are generating serious goal conflicts due to spatial variability in conditions across the EU. On the one hand these payments are contributing to the provisioning of public goods by preserving marginal agricultural land. On the other hand they are hampering agricultural development, primarily in relatively productive regions. Payments to relatively productive land that would be farmed any way not only inflate land values (capitalisation) but also slow structural change, which are both likely to hinder agricultural development and hence the competitiveness of the EU on the global market. The direct payments also increase environmental pressure; by subsidising land use generally and the associated production, they are incapable of controlling environmentally damaging emissions, which is also in conflict with broad CAP objectives. The goal conflict arises because direct payments are universal, a payment principal that does not consider spatial variability in the EU and the associated trade‐offs in regard to development and environmental effectiveness. Our analysis considered two alternative policy instruments that have the potential to curb the identified goal conflicts associated with direct payments, by applying the Polluter Pays and Provider (of public goods) Gets Principles at appropriate spatial scales. Replacing direct payments with a payment targeted on marginal land (and associated public goods) prevents land abandonment at a lower cost, by avoiding payments to relatively productive land that is farmed in any case. This also allows surviving farms in regions with relatively productive land to compensate for lost direct payments through expansion and associated scale economies, as well as higher output prices. This instrument therefore finances the provisioning of public goods without adverse effects on development and the efficiency of agricultural production. The EU‐wide tax on mineral fertiliser demonstrates that this instrument has the potential to reduce nutrient surpluses. Since direct payments cause higher levels of polluting emissions, policy instruments targeting emissions at relevant spatial scales are needed to achieve cost‐effective abatement. Overall we find that Pillar I direct payments are not addressing the diversity of challenges facing European agriculture. In fact our quantitative analysis indicates that the potential for the current system to meet these challenges is seriously impaired by goal conflicts and spatial variability across the EU. A better policy requires that instruments are targeted on desired outcomes and designed according to sound principles, specifically the Polluter Pays and Provider Gets Principles. These principles would ensure that farmers are provided with appropriate incentives to i) generate public goods that otherwise would be underprovided; ii) mitigate environmentally damaging emissions at the lowest possible cost to society; and iii) continually strive to improve environmental performance. Such instruments are also fairer and promote a more competitive or viable agricultural sector by not obstructing structural change and hence agricultural development

    Physiological responses to low-force work and psychosocial stress in women with chronic trapezius myalgia

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    <p>Abstract</p> <p>Background</p> <p>Repetitive and stressful work tasks have been linked to the development of pain in the trapezius muscle, although the underlying mechanisms still remain unclear. In earlier studies, it has been hypothesized that chronic muscle pain conditions are associated with imbalance in the autonomic nervous system, predominantly expressed as an increased sympathetic activity. This study investigates whether women with chronic trapezius myalgia show higher muscle activity and increased sympathetic tone at baseline and during repetitive low-force work and psychosocial stress, compared with pain-free controls.</p> <p>Methods</p> <p>Eighteen women with chronic trapezius myalgia (MYA) and 30 healthy female controls (CON) were studied during baseline rest, 100 min of repetitive low-force work, 20 min of psychosocial stress (Trier Social Stress Test, TSST), and 80 min recovery. The subjects rated their pain intensity, stress and energy level every 20 min throughout the experiment. Muscle activity was measured by surface electromyography in the trapezius muscle (EMGtrap) and deltoid muscle (EMGdelt). Autonomic reactivity was measured through heart rate (HR), skin conductance (SCL), blood pressure (MAP) and respiration rate (Resp).</p> <p>Results</p> <p>At baseline, EMGtrap, stress ratings, and HR were higher in MYA than in CON. Energy ratings, EMGdelt, SCL, MAP and Resp were, however, similar in the two groups. Significant main group effects were found for pain intensity, stress ratings and EMGtrap. Deltoid muscle activity and autonomic responses were almost identical in MYA and CON during work, stress and recovery. In MYA only, pain intensity and stress ratings increased towards the end of the repetitive work.</p> <p>Conclusion</p> <p>We found increased muscle activity during uninstructed rest in the painful muscle of a group of women with trapezius myalgia. The present study could not confirm the hypothesis that chronic trapezius myalgia is associated with increased sympathetic activity. The suggestion of autonomic imbalance in patients with chronic local or regional musculoskeletal pain needs to be further investigated.</p

    The complexity of kidney disease and diagnosing it – cystatin C, selective glomerular hypofiltration syndromes and proteome regulation

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    Estimation of kidney function is often part of daily clinical practice, mostly done by using the endogenous glomerular filtration rate (GFR)-markers creatinine or cystatin C. A recommendation to use both markers in parallel in 2010 has resulted in new knowledge concerning the pathophysiology of kidney disorders by the identification of a new set of kidney disorders, selective glomerular hypofiltration syndromes. These syndromes, connected to strong increases in mortality and morbidity, are characterized by a selective reduction in the glomerular filtration of 5–30 kDa molecules, such as cystatin C, compared to the filtration of small molecules <1 kDa dominating the glomerular filtrate, for example water, urea and creatinine. At least two types of such disorders, shrunken or elongated pore syndrome, are possible according to the pore model for glomerular filtration. Selective glomerular hypofiltration syndromes are prevalent in investigated populations, and patients with these syndromes often display normal measured GFR or creatinine-based GFR-estimates. The syndromes are characterized by proteomic changes promoting the development of atherosclerosis, indicating antibodies and specific receptor-blocking substances as possible new treatment modalities. Presently, the KDIGO guidelines for diagnosing kidney disorders do not recommend cystatin C as a general marker of kidney function and will therefore not allow the identification of a considerable number of patients with selective glomerular hypofiltration syndromes. Furthermore, as cystatin C is uninfluenced by muscle mass, diet or variations in tubular secretion and cystatin C-based GFR-estimation equations do not require controversial race or sex terms, it is obvious that cystatin C should be a part of future KDIGO guidelines.publishedVersio
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