6,735 research outputs found
Review of Adaptive Leadership in the Military Context: International Perspectives by Lt.-Col. Douglas Lindsay and Cmdr. Dave Woycheshin, eds.
Review of Adaptive Leadership in the Military Context: International Perspectives by Lt.-Col. Douglas Lindsay and Cmdr. Dave Woycheshin, eds
Augmented Sustainability Measures for Scotland
We estimate and compare two empirical measures of the weak sustainability of an economy for the first time: the change in augmented green net national product (GNNP), and the interest on augmented genuine savings (GS). Yearly calculations are given for each measure for Scotland during 1992-99. Augmentation means including, using projections to 2020, production possibilities enabled by exogenous technical progress or changing terms of trade. In passing, we clarify the treatment of environmental expenditures in green accounting. The change in augmented GNNP and interest on augmented GS are both always positive, showing no sustainability problem for Scotland; but the former greatly exceeds the latter, showing an unresolved problem with the theorysustainability, Scotland, genuine savings, green NNP, augmentation
Use of elastic stability analysis to explain the stress-dependent nature of soil strength
The peak and critical state strengths of sands are linearly related to the stress level, just as the frictional resistance to sliding along an interface is related to the normal force. The analogy with frictional sliding has led to the use of a ‘friction angle’ to describe the relationship between strength and stress for soils. The term ‘friction angle’ implies that the underlying mechanism is frictional resistance at the particle contacts. However, experiments and discrete element simulations indicate that the material friction angle is not simply related to the friction angle at the particle contacts. Experiments and particle-scale simulations of model sands have also revealed the presence of strong force chains, aligned with the major principal stress. Buckling of these strong force chains has been proposed as an alternative to the frictional-sliding failure mechanism. Here, using an idealized abstraction of a strong force chain, the resistance is shown to be linearly proportional to the magnitude of the lateral forces supporting the force chain. Considering a triaxial stress state, and drawing an analogy between the lateral forces and the confining pressure in a triaxial test, a linear relationship between stress level and strength is seen to emerge from the failure-by-buckling hypothesis
Illegitimate Medical Purpose: Resolving the Fundamental Flaw in Criminal Prosecutions Involving Physicians Charged with Overprescribing Prescription Opioids
A perspective on the importance of within-tree variation in mortality risk for a leaf-mining insect
Within-tree variation in abiotic conditions can create a mosaic of fitness gradients for herbivorous insects. To explore these effects, we quantified the patterns of mortality of the solitary oak leafminer, <i>Cameraria hamadryadella</i> (Lepidoptera: Gracillariidae), which lives within leaves of white oak, <i>Quercus alba</i>. We found differential patterns of survival and larval feeding rate within the tree and in association with several abiotic factors: light levels, leaf nitrogen content, and canopy height. We suggest that the leaf scale microhabitat conditions are fundamental to plant-herbivore-enemy interactions because of the differential fitness effects on herbivores. Such effects would be missed by studies that average effects by whole plants. Our study population of <i>C. hamadryadella</i> is located within the Orland E. White State Arboretum of Virginia in Boyce, Virginia, USA
Comparisons between systems to measure contact and flight times in elite race walking
Race walking is an Olympic event dictated by a rule that states that no visible loss of contact with the ground should occur and that the leg must be straightened from first contact with the ground until the ‘vertical upright position’ (IAAF Rule 230.2). The measurement of flight times during race walking is therefore of great interest to coaches, athletes and judges. The aim of the study was to compare different methodologies used to measure contact and flight time in race walking. Ten male race walkers (stature: 1.78 m (± 0.05), mass: 64.4 kg (± 4.9)) and seven female race walkers (stature: 1.68 m (± 0.10), mass: 56.7 kg (± 11.0)) participated. Fourteen of the athletes had competed at the 2016 Olympic Games or 2017 World Championships. The men race walked down an indoor track at 11, 12, 13, 14 and 15 km/h (measured using timing gates and in a randomised order), whereas the women’s trials were at 10, 11, 12, 13 and 14 km/h. Contact and flight times were measured for the midsection of each trial using three adjacent 900 x 600 mm Kistler force plates (1000 Hz), 5 x 1 m strips of an OptoJump Next system (1000 Hz) and a Fastec high-speed camera (500 Hz). Results from the OptoJump Next system were extracted using five settings based on the number of LEDs that needed activating (contact begins after_contact ends when), and were annotated as 0_0, 1_1, 2_2, 3_3 and 4_4. The force plate values were considered the criterion values and measurements were assessed for reliability using Intraclass Correlation Coefficients (ICC) and 95% limits of agreement (LOA: bias ± random error). For flight time, the ICCs between the force plate and OptoJump Next were 0.846 for the 0_0 condition (LOA: .011 ± .014 s), 0.901 (1_1) (LOA: .008 ± .014 s), 0.983 (2_2) (LOA: .000 ± .008 s), 0.844 (3_3) (LOA: –.011 ± .014 s), and 0.563 (4_4) (LOA: –.023 ± .018 s). The ICC between the force plate and the high-speed video for flight time was 0.975 (LOA: –.003 ± .008 s). For contact time, the ICCs between the force plate and OptoJump Next were 0.967 for the 0_0 condition (LOA: –.011 ± .011 s), 0.982 (1_1) (LOA: –.008 ± .010 s), 0.995 (2_2) (LOA: .000 ± .010 s), 0.960 (3_3) (LOA: .011 ± .016 s), and 0.874 (4_4) (LOA: .024 ± .015 s). The ICC between the force plate and the high-speed video condition for contact time was 0.991 (LOA: .004 ± .010 s). The OptoJump Next system provided results similar to those of the gold standard force plates, with the 2_2 setting the most reliable. Users of the OptoJump Next system should therefore note that adjusting the settings of the device (from 0_0, the most likely default setting) might be necessary to achieve the most accurate results. The high-speed video recordings also provided very good reliability although the time-consuming nature of video analysis means the OptoJump Next system is better suited to providing immediate results
Measure of agreement between experts on apple damage assessment
Quoique l'évaluation des dommages soit un exercice important et fréquent en entomologie appliquée, il n'y a pas d'études publiées concernant le degré de concordance des évaluations de dommages par les experts. Au cours de cette étude, effectuée lors de la 50e Conférence en lutte intégrée des vergers de l'État de New York, de la Nouvelle-Angleterre et du Canada, quatre équipes d'experts ont évalué, de façon indépendante, les dommages causés sur 200 pommes. Les participants ont identifié 22 types de dommages causés par les insectes, 8 par des maladies et 8 reliés à d'autres causes. Nous avons calculé un degré de concordance pour chaque type de dommage. Les degrés de concordance les plus bas concernaient les dommages du charançon de la prune (Conotrachelus nénuphar) [Coleoptera : Curculionidae] (71,8%), de la punaise terne (Lygus lineolaris) [Hemiptera : Miridae] (83,2 %) et les dommages causés par les larves de lépidoptères en début de saison (87,1 %). On discute de l'utilité de l'usage du degré de concordance dans le contexte de plusieurs situations de lutte intégrée.Although damage evaluation is an important and frequent exercise in economic entomology, there are no quantitative studies on inter-rater agreement of experts. In this experiment conducted during the 50th New York, New England and Canadian Pest Management Conference, four teams of experts independently estimated the damage on 200 apples at harvest. The participants identified 22 types of damage caused by insects, 8 by diseases, and 8 related to other causes. For each type of damage an average measure of agreement was calculated. The lowest average agreements were found in plum curculio (Conotrachelus nenuphar) [Coleoptera : Curculionidae] damage (71.8%), tarnished plant bug (Lygus lineolaris) [Hemiptera : Miridae] damage (83.2%), and by early lepidoptera damage (87.1%). The usefulness of inter-rater agreement experiments is discussed in the context of many situations pertaining to crop protection
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