Parametrical optimization of laser surface alloyed NiTi shape memory alloy with Co and Nb by the Taguchi method

Different high-purity metal powders were successfully alloyed on to a nickel titanium (NiTi) shape memory alloy (SMA) with a 3 kW carbon dioxide (CO2) laser system. In order to produce an alloyed layer with complete penetration and acceptable composition profile, the Taguchi approach was used as a statistical technique for optimizing selected laser processing parameters. A systematic study of laser power, scanning velocity, and pre-paste powder thickness was conducted. The signal-to-noise ratios (S/N) for each control factor were calculated in order to assess the deviation from the average response. Analysis of variance (ANOVA) was carried out to understand the significance of process variables affecting the process effects. The Taguchi method was able to determine the laser process parameters for the laser surface alloying technique with high statistical accuracy and yield a laser surface alloying technique capable of achieving a desirable dilution ratio. Energy dispersive spectrometry consistently showed that the per cent by weight of Ni was reduced by 45 per cent as compared with untreated NiTi SMA when the Taguchi-determined laser processing parameters were employed, thus verifying the laser's processing parameters as optimum

The effect of match standard and referee experience on the objective and subjective match workload of English Premier League referees

The aim of the present study was to examine the effect of match standard and referee experience upon the objective and subjective workload of referees during Premier and Football league soccer matches. We also examined the relationship between heart rate (HR) and ratings of perceived exertion (RPE) for assessing match intensity in soccer referees. Heart rate responses were recorded using short-range telemetry and RPE scores were collected using a 10-point scale. Analysis revealed a significant relationship between mean match HR and match RPE scores (r = 0.485, p < 0.05, n =18). There were significant differences in match HR (Premier league 83.6 2.6 %HRmax vs. Football league 81.5 2.2 %HRmax, p < 0.05) and match RPE scores (Premier league 7.8 0.8 vs. Football league 6.9 0.8, p < 0.05) between standards of competition. Referee experience had no effect upon match heart rate and RPE responses to Premier and Football league matches. The results of the present study demonstrate the validity of using HR and RPE as a measure of global match intensity in soccer referees. Referee experience had no effect upon the referees’ objective and subjective match workload assessments, whereas match intensity was correlated to competition standard. These findings have implications for fitness preparation and evaluation in soccer referees. When progressing to a higher level of competition, referees should ensure that appropriate levels of fitness are developed in order to enable them to cope with an increase in physical match demands

Coupling of climate models and ice sheet models by surface mass balance gradients: application to the Greenland Ice Sheet

It is notoriously difficult to couple surface mass balance (SMB) results from climate models to the changing geometry of an ice sheet model. This problem is traditionally avoided by using only accumulation from a climate model, and parameterizing the meltwater run-off as a function of temperature, which is often related to surface elevation (<i>H</i><sub>s</sub>). In this study, we propose a new strategy to calculate SMB, to allow a direct adjustment of SMB to a change in ice sheet topography and/or a change in climate forcing. This method is based on elevational gradients in the SMB field as computed by a regional climate model. Separate linear relations are derived for ablation and accumulation, using pairs of <i>H</i><sub>s</sub> and SMB within a minimum search radius. The continuously adjusting SMB forcing is consistent with climate model forcing fields, also for initially non-glaciated areas in the peripheral areas of an ice sheet. When applied to an asynchronous coupled ice sheet – climate model setup, this method circumvents traditional temperature lapse rate assumptions. Here we apply it to the Greenland Ice Sheet (GrIS). Experiments using both steady-state forcing and glacial-interglacial forcing result in realistic ice sheet reconstructions

Групповая эргатическая совместимость авиационных операторов в процессе эксплуатации авионики

Рассмотрены проблемы групповой эргатической совместимости авиационных операторов (пилотов, авиадиспетчеров, технического персонала) и использования технических средств для оценки групповой эргатической совместимости операторов как средства повышения авиационной безопасности за счет более тщательного отбора кандидатов для совместной работы в составе лeтных и космических экипажей.Розглянуто питання проблеми групової ергатичної сумісності авіаційних операторів (пілотів, авіадиспетчерів, технічного персоналу) і використання технічних пристроїв для оцінки групової ергатичної сумісності операторів як засобу підвищення авіаційної безпеки за рахунок більш кращого відбору кандидатів для спільної роботи у складі льотних і космічних екіпажів.We issued the problems of group ergatic aircraft operators (pilots, air traffic controllers, technicians) and the use of technical devices to assess the compatibility of the group ergatic operators as means of improving aviation safety through a better selection of candidates to work together as part of flight and space crews. In this research article to better selection of candidates for collaboration in the space flight crews and the authors propose to use modern computers with appropriate software. This computer complex will answer a number of important issues related to ensuring: compatibility Soames, rational distribution of functions between components ergatic systems, proper interaction with the machine operators as well as each other in normal and special situations professional selection, preparation and training of aviation operators

Approaches to identify the value of seminatural habitats for conservation biological control

Invertebrates perform many vital functions in agricultural production, but many taxa are in decline, including pest natural enemies. Action is needed to increase their abundance if more sustainable agricultural systems are to be achieved. Conservation biological control (CBC) is a key component of integrated pest management yet has failed to be widely adopted in mainstream agriculture. Approaches to improving conservation biological control have been largely ad hoc. Two approaches are described to improve this process, one based upon pest natural enemy ecology and resource provision while the other focusses on the ecosystem service delivery using the QuESSA (Quantification of Ecological Services for Sustainable Agriculture) project as an example. In this project, a predictive scoring system was developed to show the potential of five seminatural habitat categories to provide biological control, from which predictive maps were generated for Europe. Actual biological control was measured in a series of case studies using sentinel systems (insect or seed prey), trade-offs between ecosystem services were explored, and heatmaps of biological control were generated. The overall conclusion from the QuESSA project was that results were context specific, indicating that more targeted approaches to CBC are needed. This may include designing new habitats or modifying existing habitats to support the types of natural enemies required for specific crops or pests

Diverse roles of androgen receptor (AR) domains in AR-mediated signaling

Androgens control male sexual development and maintenance of the adult male phenotype. They have very divergent effects on their target organs like the reproductive organs, muscle, bone, brain and skin. This is explained in part by the fact that different cell types respond differently to androgen stimulus, even when all these responses are mediated by the same intracellular androgen receptor. To understand these tissue- and cell-specific readouts of androgens, we have to learn the many different steps in the transcription activation mechanisms of the androgen receptor (NR3C4). Like all nuclear receptors, the steroid receptors have a central DNA-binding domain connected to a ligand-binding domain by a hinge region. In addition, all steroid receptors have a relatively large amino-terminal domain. Despite the overall structural homology with other nuclear receptors, the androgen receptor has several specific characteristics which will be discussed here. This receptor can bind two types of androgen response elements (AREs): one type being similar to the classical GRE/PRE-type elements, the other type being the more divergent and more selective AREs. The hormone-binding domain has low intrinsic transactivation properties, a feature that correlates with the low affinity of this domain for the canonical LxxLL-bearing coactivators. For the androgen receptor, transcriptional activation involves the alternative recruitment of coactivators to different regions in the amino-terminal domain, as well as the hinge region. Finally, a very strong ligand-induced interaction between the amino-terminal domain and the ligand-binding domain of the androgen receptor seems to be involved in many aspects of its function as a transcription factor. This review describes the current knowledge on the structure-function relationships within the domains of the androgen receptor and tries to integrate the involvement of different domains, subdomains and motifs in the functioning of this receptor as a transcription factor with tissue- and cell-specific readouts

Impact of an invasive alien plant on litter decomposition along a latitudinal gradient

Invasive alien plant effects on ecosystem functions are often difficult to predict across environmental gradients due to the context-dependent interactions between the invader and the recipient communities. Adopting a functional trait-based framework could provide more mechanistic predictions for invasive species' impacts. In this study, we contrast litter decomposition rates among communities with and without the invasive plant Impatiens glandulifera in five regions along a 1600 km long latitudinal gradient in Europe. Across this gradient, four functional traits, namely leaf dry matter content (LDMC), specific leaf area (SLA), stem-specific density (SSD), and plant height, are correlated to rates of litter decomposition of standardized rooibos (labile), green tea (recalcitrant), and I. glandulifera litter. Our results show that both invaded and non-invaded plant communities had a higher expression of acquisitive traits (low LDMC and SSD, high SLA) with increasing temperature along the latitudinal gradient, partly explaining the variation in decomposition rates along the gradient. At the same time, invasion shifted community trait composition toward more acquisitive traits across the latitudinal gradient. These trait changes partly explained the increased litter decomposition rates of the labile litter fraction of rooibos and I. glandulifera litter in invaded communities, a shift that was most evident in the warmer study regions. Plant available nitrogen was lower in invaded communities, likely due to high nutrient uptake by I. glandulifera. Meanwhile, the coldest study region was characterized by a reversed effect of invasion on decomposition rates. Here, community traits related to low litter quality and potential allelopathic effects of the invader resulted in reduced litter decomposition rates, suggesting a threshold temperature at which invader effects on litter decomposition turn positive. This study therefore illustrates how functional trait changes toward acquisitive traits can help explain invader-induced changes in ecosystem functions such as increased litter decomposition

Activity profile of top-class association football referees in relation to fitness test performance and match standard

The aim of this study was to examine the kinematic activity profiles, cardiovascular responses and physical fitness of top-class football referees (n=11) during the FIFA Confederations Cup 2005. Computerised match-analyses (n=9) were performed with a two-dimensional photogrammetric video system, and the cardiovascular demand imposed on the referees (n=12) was measured using heart rate recordings. Total distance covered was 10,218, s=643 m of which 3531, s=510 m was covered at high intensities (>3.6 m.s(-1)). Both total distance covered (r2=0.59; P=0.02) and high-intensity activities (r2=0.44; P=0.05) were related to the distance covered by the ball in the same match. The referees ran at high speed 37% further (P=0.01) in the actual tournament than during under-17 top-level officiating. After the 5-min interval during which high-speed running peaked, in the following 5 min the performance was reduced by 19% (P=0.01) in relation to the mean of the game. Mean heart rate was 161, s=9 b.min(-1) (86, s=3% of maximal heart rate (HRmax)). Mean heart rate (expressed as percentage of HRmax) was related in part (r2=0.36; P5 m.s(-1)) best describes the physical performance of referees; (3) heart rate recording can be a useful tool to determine the most intense periods of a match and (4) the new fitness tests adopted by FIFA were poor predictors of match activities