IMPACT OF BODY COMPOSITION AND VO2 MAX ON THE COMPETITIVE SUCCESS IN TOP-LEVEL HANDBALL PLAYERS

The purpose of the study was to determine the morphological and functional characteristics of 32 Serbian national U20 handball players (age 20.43±1.16y; training experience 8.12±1.89y) before European championship in Switzerland (2006) and to determinate their impact on competitive performance and outstanding success achieved. The results show that wing players differ from other players in morphological characteristics. Values for body height, weight, BMI, muscle mass and fat mass were significantly lower compared to the other playing positions. Extremely low values of maximal oxygen uptake (VO2 max) were measured in all players (ranged from 2.68 to 4.66 l×min-1). Pivots had the highest VO2 max in absolute values (3.76 l×min-1), and wing players in relative terms (40.83 ml×kg-1×min-1). Handball is characterized by high intensity intermittent play, followed by a number of walking breaks and quick substitutions. This makes possible to retain high playing intensity during whole match, because players can be given rest periods whenever needed. This will result in a high intensity game that does not necessarily require high VO2 max. Competitive success in modern top-level handball might be more reliant on optimal tactical preparation than on the body composition and VO2 max of an individual athlete

Smoothed particle hydrodynamics for blood flow analysis: development of particle lifecycle algorithm

The aim of this research was to facilitate the application of Smoothed Particle Hydrodynamics (SPH) method to Computational Fluid Dynamics analysis of turbulent flow through complex geometry blood vessels, and to compare it with the state-of-the-art Finite Element Method (FEM). SPH offers the possibility to observe motion of fluid fragment or particle inclusion within the Lagrangian material framework, giving researchers greater insight into the Fluid-Structure interaction such as transportation and distribution of medical particles, or buildup of plaque in atherosclerosis. In order to generate the fluid flow in SPH, the particles are created at inlet, and destroyed at the outlet. In this paper we present a novel lifecycle algorithm for generation and destruction of the particles using particle types, which is more flexible and suitable for the complex geometry models in comparison to the current state of the art commercial solutions, which use boundary planes. Our algorithm features mother and new-born particle types located at inlets used for the particle flow generation, and at the outlets, we have dying and killer particle types, which are used for deletion of particles. Based upon the current neighbors, the type of the particle is updated within the nearest neighbor search method, which is invoked in each time step. The capabilities of the new algorithm are demonstrated using a benchmark example and a realistic patient specific geometry, showing similar results, but the SPH advantages of particle tracking are yet to be utilized in our future work.Ministry of Education, Science and Technological Development of the Republic of SerbiaPublishe

Effekte der Schwarzbrache in verschiedenen Trockenfeldbauregionen der GUS

In der Waldsteppenzone der Orlovskaya Oblast (haplic Phaeozems und haplic Chernozems) und in der Zone der typischen Steppen des Altai Krai (calcic Chernozems und haplic Kastanozems) wurden im Rahmen dieser Untersuchung verschiedene Bodenbearbeitungssysteme verglichen (konventionelle Bodenbearbeitung - CT, minimale Bodenbearbeitung - MT und Direktsaat - NT). Die Untersuchungen fanden in stark auf Getreideproduktion ausgerichteten Ackerbausystemen statt (Winterweizen - Ww, Sommerweizen - Ws, Sommergerste - Bs). Eine in Russland weit verbreitete und absolut übliche konventionelle dreijährige Getreidefruchtfolge, mit Schwarzbrache wurde als “best practice” vergleichend hinzugezogen (Getreide - Getreide - Schwarzbrache). An jedem Standort wurden vier Versuchsfelder in die Untersuchung einbezogen. Am Standort der Waldsteppenzone (mittlerer Niederschlag 600mm/a) konnte unter Schwarzbrache (auf einem haplic Phaeozem) innerhalb eines Anbauzyklus (September 2008 - August 2009) eine Erhöhung des Bodenfeuchtegehaltes um 34% festgestellt werden; verglichen mit dem Bodenfeuchteniveau unter MT und Ww-Bestand (haplic Chernozem). Die Böden unter CT-Bewirtschaftung (haplic Chernozems) je im ersten, bzw. im zweiten Jahr nach Schwarzbrache, zeigen gleiche (-4,1%) oder sogar schlechtere (-15,1%) Bodenfeuchtewerte, verglichen mit den Werten des Bodens unter MT-Bewirtschaftung, ebenfalls unter Ww-Bestand. Am Standort in der Region der typischen Steppen im Altai Krai (mittlerer Niederschlag ca. 320mm/a) konnte unter Schwarzbrache im Zeitraum April - August 2009 ungefähr 20% mehr Bodenfeuchte gehalten werden als unter NT-Bewirtschaftung und Ws-Bestand (beide Böden haplic Kastanozem). Im ersten Jahr nach Schwarzbrache unter Ws-Bestand fiel der Bodenfeuchtegehalt um -7,8% gegenüber dem Boden unter NT-Bewirtschaftung ab (calcic Chernozem). Am Waldsteppenstandort in der Orlovskaya Oblast konnte aufgrund der höheren mechanischen Bearbeitungsintensität und des geringeren Nährstoffentzugs unter Schwarzbrache, die Konzentration an pflanzenverfügbarem Stickstoff in der Ackerkrume um 500% gegenüber dem Boden unter MTBewirtschaftung und unter Ww-Bestand erhöht werden (Zeitraum April - August 2009). Doch bereits im ersten Folgejahr nach Schwarzbrache fiel im konkreten Fall die Stickstoffkonzentration auf einen, mit dem im Boden unter MT-Bewirtschaftung und ebenfalls unter Ww-Bestand, vergleichbaren Wert zurück. Vor dem Hintergrund der wesentlich trockeneren Witterung am westsibirischen Standort der typischen Steppe sinkt der Nitratgehalt unter Schwarzbrache deutlich ab, während der Ammoniumgehalt über den Zeitraum der Untersuchungen hinweg anstieg. Des weiteren wird aufgrund der geringeren Auswaschung im strengen sibirischen Winter im ersten Frühjahr nach Schwarzbrache ein, gegenüber dem Boden unter N-Bewirtschaftung, zweifach höherer Nitratgehalt gemessen. Doch auch hier ist bereits nach der ersten Anbausaison nach Schwarzbrachehaltung (Mai - August 2009) die Nitratkonzentration auf ein Wert zurückgegangen, der mit dessen im Boden unter NTBewirtschaftung vergleichbar ist.The studies in a forest steppe region (haplic Phaeozems and haplic Chernozems) in Orlovskaya 164 „Grunwald et al.: Effekte der Schwarzbrache in verschiedenen Trockenfeldbauregionen der GUS“ Oblast (RF) and in steppe region (calcic Chernozems and haplic Kastanozems) in Altay Kray (RF) compared different tillage systems (conventional tillage CT, minimum tillage MT, no tillage NT) in highly grain focused crop rotations (winter wheat Ww, spring wheat Ws, spring barley Bs). A conventional till crop rotation (Grain – Grain – Bare Fallow), which is very common in Russian agriculture, as the most intensive tillage method, was chosen for comparison under best practice. At each site four sample fields have been studied. In forest steppe region (precipitation around 600mm/a) during one crop production period (Sept. 2008 – Aug. 2009) under bare fallow (haplic Phaeozem) the soil moisture storage has been enriched about 34% comparing to haplic Chernozems under MT with Ww. In two haplic Chernozems under CT system in the 1st and 2nd year after bare fallow, it was cropped Ww too, have been shown comparable (-4.1%) and worse moisture conditions (-15.1%) compared to this haplic Chernozem under MT regime. In steppe region in Altay Kray (precipitation on test site around 320mm/a) during the growing season 2009 (April/May – August) under bare fallow (haplic Kastanozem) has been stored 0% more water than under NT (haplic Kastanozem with Bs). In the 1st year after fallow and with Ws production (calcic Chernozem) the moisture level has been declined to -7.8% compared to this soil under NT management. Due to the much higher tillage intensity and the less nutrient consumption under bare fallow, the nitrate concentration in higher soil horizon increased about 500% comparing the situation under MT and Ww in Orlovskaya Oblast during the growing period 2009 (April – August). But already in the 1st year after fallow the nitrate concentration declined to a comparable level with the soil under MT and under Ww production too. Because of the much dryer conditions in steppe region of southern Siberia the nitrate level under bare fallow declined, while the ammonia level increased. Also due to less eluviation during the winter time in the 1st spring after bare fallow (2009) the nitrate level in a calcic Chernozem under Ws is about two times higher (8.5 mg/kg) than under NT management (haplic Kastanozem with Bs) at the same test site. Already after the 1st growing season (May – August 2009) the nitrate concentrations under CT with Ws (2.8mg/kg) declined to a comparable level with the soil under NT with Bs (2.4 mg/kg). Furthermore wind erosion has been established as the most dangerous threat for soil carbon level and fertility of arable lands in steppe regions. The silt concentration in tillage horizons under CT (0 – 35cm) declined during the last decades in both research areas. Due to the higher threat of wind erosion in southern Siberian steppe regions the silt concentrations declined more than 4% in comparison to lower soil horizons

REFINE: Reachability-based Trajectory Design using Robust Feedback Linearization and Zonotopes

Performing real-time receding horizon motion planning for autonomous vehicles while providing safety guarantees remains difficult. This is because existing methods to accurately predict ego vehicle behavior under a chosen controller use online numerical integration that requires a fine time discretization and thereby adversely affects real-time performance. To address this limitation, several recent papers have proposed to apply offline reachability analysis to conservatively predict the behavior of the ego vehicle. This reachable set can be constructed by utilizing a simplified model whose behavior is assumed a priori to conservatively bound the dynamics of a full-order model. However, guaranteeing that one satisfies this assumption is challenging. This paper proposes a framework named REFINE to overcome the limitations of these existing approaches. REFINE utilizes a parameterized robust controller that partially linearizes the vehicle dynamics even in the presence of modeling error. Zonotope-based reachability analysis is then performed on the closed-loop, full-order vehicle dynamics to compute the corresponding control-parameterized, over-approximate Forward Reachable Sets (FRS). Because reachability analysis is applied to the full-order model, the potential conservativeness introduced by using a simplified model is avoided. The pre-computed, control-parameterized FRS is then used online in an optimization framework to ensure safety. The proposed method is compared to several state of the art methods during a simulation-based evaluation on a full-size vehicle model and is evaluated on a 1/10th race car robot in real hardware testing. In contrast to existing methods, REFINE is shown to enable the vehicle to safely navigate itself through complex environments

SUSTAINABLE DEVELOPMENT OF TRUST AND POLICE PRESENCE IN SCHOOLS: IMPLICATIONS FOR SCHOOL SAFETY POLICY

The study aims to determine the trust and presence of police officers in schools in Serbia, as well as the perception of the principals and secretaries, teachers and staff, parents, and students on how successful the specific police units dedicated to schools were in fulfilling their tasks. The ex-post analysis was conducted through PEST/SWAT analysis, mapping the key actors and using batteries of online questionnaires, besides interviews with the MOI representatives, surveyed with personal interviewing, computer-aided surveying, desk analysis, and content analysis. The survey was conducted from September 2021 to June 2022. The research methods were implemented in 1140 schools in Serbia, and 8,617 people were included in surveys: police officers (308); principals and secretaries (1085); the team for protection against discrimination (982); teachers and staff (2988); parents (938) and students (2316). The relationships between the covariates and perception were investigated using the t-test, one-way ANOVA, multivariate linear regression, and binary regression. The results showed that a project of school police officers was not fully recognized as one of the strategically essential instruments for safe schools; trust is low, but presence is high. Besides that, the results suggest that the entire public believes that police are needed in schools and that it positively affects school safety. Regarding school safety policy, it is necessary to undertake three measures for the sustainable development of trust and the presence of police in school: regulatory, informative-educational, and institutional-organizational.

Market risk management in a post-Basel II regulatory environment

We propose a novel method of Mean-Capital Requirement portfolio optimization. The optimization is performed using a parallel framework for optimization based on the Nondominated Sorting Genetic Algorithm II. Capital requirements for market risk include an additional stress component introduced by the recent Basel 2.5 regulation. Our optimization with the Basel 2.5 formula in the objective function produces superior results to those of the old (Basel II) formula in stress scenarios in which the correlations of asset returns change considerably. These improvements are achieved at the expense of reduced cardinality of Pareto-optimal portfolios. This reduced cardinality (and thus portfolio diversification) in periods of relatively low market volatility may have unintended consequences for banks’ risk exposure

La expiación : la escuadra de Puerto-Arturo

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