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Loss functions for structural flood mitigation measures

The paper aims at discussing the methodology used to develop loss functions for flood mitigation measures, using historic data of flood damage to infrastructure. The main determinants of the extent of damage are the size of the flood and the length of the infrastructure within the boundaries of the flood-line. In regression analysis, flood peak was used as the independent variable in the Cobb-Douglas functions to depict the relationship between damage and flood peak. The Mfolozi flood-plain in Northern KwaZulu-Natal served as the study area. Loss functions for infrastructure, for ex ante estimation of damage to infrastructure, were developed for inclusion in a flood damage simulation model (FLODSIM) developed by the Department of Agricultural Economics of the University of the Orange Free State in collaboration with the Water Research Commission. Loss functions were determined for spillways, levees, tramlines, public roads, drains and bridges. WaterSA Vol.27(1) 2001: 35-3

Variability of Annual Iowa Precipitation During the Past 95 Years

With increased consumption of fossil fuels has come warnings that the global atmosphere could be overtaxed with carbon dioxide and other combustion byproducts. The most popular scenario suggests a warming of the subpolar area with an extension of the grain belt. This warming could place the present grain belt in a warmer and drier climate. Each time a portion of the grain belt experiences a temperature or precipitation anomaly, the suggestion of a climatic change is raised. The present paper addresses the question of medium-term, 95-year change in Iowa annual precipitation as well as linkage between precipitation and temperature anomalies. Similar studies in Europe and the United Kingdom, where unbroken precipitation records extend back almost 300 years, show periods up to 50 or 75 years where a jump in the annual mean has occurred. The fact that such anomalies extend back before the industrial revolution suggests other factors may cause such changes. With only about 100 years of climatological records here in the grain belt, it may not be possible to identify long-term, natural oscillations or a true, long-term trend. Records at four sites, Cedar Rapids, Des Moines, Dubuque, and Storm Lake, were analyzed in search of true jumps or trends in the climatic record. There was no question that the record had dry and wet periods, some extending over a period of ten or fifteen years. The conclusions were that, although extended periods seemed to be above or below the long-term mean, these anomalies had tenuous linkage between sites across the state. Possibly because of the sample size, no statistically significant trends were observed between sites through the years 1890-1984. Several poorly defined single site jumps were observed in the precipitation record, however, these were not clearly linked to companion temperature perturbations

A COMPARISON OF RESISTED AND ASSISTED SPRINT TRAINING IN COLLEGIATE SPRINTERS

Sprint time (ST) is the product of stride length (SL) and stride rate (SR). Increases in either of these variables results in speed improvement. Purpose:  To compare resisted (RST) and assisted sprint training (AST) on sprint performance. Methods:  Twenty (10 male, 10 female) collegiate sprinters and hurdlers were randomly divided into two training groups: RST (age: 21.8±1.8yrs, height: 1.73±0.10m, mass: 69.5±12.8kg) and AST (age: 22.2±2.4yrs, height: 1.76±0.10m, mass: 69.1±9.9kg). Each group trained 3 days/week for 6 weeks. The RST group used a combination of weighted sled pulls, uphill sprinting and depth jumps. The AST group combined downhill running, towing, sprint ladders and single leg bounds. Prior to and following the training interventions SL and ST (10 meter sprint time) were recorded at sprint distances of 30m, 60m, and 120m during the last 10 meters of each sprint distance. Pre-post training ST and SL were compared within training groups at each sprint distance using paired t-tests. Additionally, a gain score was calculated by taking the difference between the post and pre test scores. The gain scores for SL and ST were compared between training groups via independent t-tests at each sprint distance. Results: For the RST 30m, ST (1.18±0.08s vs 1.14±0.08s, p<0.01) and SL (2.06±0.08m vs. 2.09±1.14m, p<0.01) were significantly improved. For the AST, 30m ST (1.19±0.08s vs. 1.18±0.08s, p<0.01) and SL (2.10±0.13m vs. 2.11±0.13, p=0.04) were significantly improved. No improvements in ST or SL were detected for either the RST or AST groups at the 60m sprint distance. For the RST 120m, ST (1.13±0.07s vs. 1.12±0.08s, p<0.01) was significantly improved. For the AST 120m, ST (1.12±0.07s vs. 1.11±0.07s, p<0.01) and SL (2.30±0.08 vs. 2.33±0.08, p<0.01) were significantly improved. At the 30M interval, the RST demonstrated significant improvements in SL and ST as compared to the AST (p<0.01). However, at the 120M interval, the AST demonstrated a significant improvement in SL as compared to the RST (p<0.01). Conclusion: Within the parameters of this study, RST and AST methods have proven effective at improving sprint performance. It appears that RST protocols may be of greatest benefit for improving sprint performance at shorter distances, while AST protocols may be of greater benefit at longer sprinting distances.  Article visualizations

CONTINUOUS WEIGHTED JUMPING: EFFECTS ON VERTICAL JUMP HEIGHT

High intensity, near maximal exercise is a conditioning activity which can cause neural hyper-stimulation and lead to acute enhanced power production known as post-activation potentiation (PAP). Investigations need to be conducted to better understand the duration and intensity of the conditioning activity and subsequent effects on the fatigue-potentiation relationship. Purpose: To investigate the effect of 30 seconds of continuous vertical jumping while wearing a vest loaded with 30% of body weight on power output as measured with a maximal vertical jump (VJ). Methods: 14 volunteers (8 weight trained males [23.0+2.9 yrs, 79.8+13.8 kg, 179.9+8.6 cm] and 6 weight trained females [23.0+2.9 yrs, 69.9+13.3 kg, 171.6+7.0 cm]) participated in the study. Pre-testing consisted of each participant performing 3 VJs. The highest VJ was recorded as baseline. A weighted vest was then loaded equaling 30% of the individual's body weight; while wearing the weighted vest, participants performed 30 seconds of continuous VJs. Immediately after jumping participants were seated in a chair for 3 minutes; at 3 minutes, they performed a maximal VJ without the weighted vest in the same manner as done during pre-testing. Two additional VJs were repeated at 4 and 5 minutes post weighted jumping. A mixed design ANOVA with repeated measures was performed. Results: Results showed main effects for each of the independent variables tested, gender and jump. The posttest values at all 3 intervals for both males and females were significantly different from the pretest scores (F [3, 36] = 21.74, p < 0.05). Post hoc analysis indicated that the pretest VJ scores (M = 280.1±18.6 cm) decreased significantly at the 3 minute interval (M = 278.1±18.3 cm), followed by a significant increase in height at the 4 minute interval (M = 281.1±18.7 cm), and another increase at the 5 minute interval (M = 283.0±19.2 cm). Males jumped significantly higher than the females across all trials (p<0.05), however there was no significant difference between male and female VJ gain scores between pre-PAP VJ and 3, 4 and 5 minute post weighted exercise VJ. Conclusion: Results suggest that 30 seconds of weighted VJs causes fatigue which decreases VJ at 3 minutes post exercise. However, a PAP effect was seen at 4 and 5 minutes post weighted exercise significantly increasing VJ above pre testing. From a practical perspective, coaches must be aware of the complex nature of the fatigue-potentiation relationship when attempting to elicit a PAP effect in the individual athlete.   Article visualizations

Coaligned dual-channel STED nanoscopy and molecular diffusion analysis at 20 nm resolution.

We report on a fiber laser-based stimulated emission-depletion microscope providing down to ~20 nm resolution in raw data images as well as 15–19 nm diameter probing areas in fluorescence correlation spectroscopy. Stimulated emission depletion pulses of nanosecond duration and 775 nm wavelength are used to silence two fluorophores simultaneously, ensuring offset-free colocalization analysis. The versatility of this superresolution method is exemplified by revealing the octameric arrangement of Xenopus nuclear pore complexes and by quantifying the diffusion of labeled lipid molecules in artificial and living cell membranes

Unique Multiorganizational Collaborative Proves Effective in Delivering 2014 Farm Bill Education

The Agricultural Act of 2014 is critical to the economic safety net for U.S. producers. This act represented a major change in philosophy, requiring producers to make key decisions about their options on the basis of risk management. To add to the complexity of the issue, the time period for delivering applicable education to landowners before sign-up deadlines was relatively short. This article highlights a unique multiorganizational statewide approach to delivering the applicable education. It involved University of Minnesota Extension, the Center for Farm Financial Management, the U.S. Department of Agriculture, and banks and resulted in substantive evaluative outcomes

The effect of inhomogeneous compression on water transport in the cathode of a proton exchange membrane fuel cell

A three-dimensional, multicomponent, two-fluid model developed in the commercial CFD package CFX 13 (ANSYS Inc.) is used to investigate the effect of porous media compression on water transport in a proton exchange membrane fuel cell (PEMFC). The PEMFC model only consist of the cathode channel, gas diffusion layer, microporous layer, and catalyst layer, excluding the membrane and anode. In the porous media liquid water transport is described by the capillary pressure gradient, momentum loss via the DarcyForchheimer equation, and mass transfer between phases by a nonequilibrium phase change model. Furthermore, the presence of irreducible liquid water is taken into account. In order to account for compression, porous media morphology variations are specified based on the gas diffusion layer (GDL) through-plane strain and intrusion which are stated as a function of compression. These morphology variations affect gas and liquid water transport, and hence liquid water distribution and the risk of blocking active sites. Hence, water transport is studied under GDL compression in order to investigate the qualitative effects. Two simulation cases are compared; one with and one without compression