828 research outputs found

    On coupled systems of Kolmogorov equations with applications to stochastic differential games

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    We prove that a family of linear bounded evolution operators (G(t,s))tsI({\bf G}(t,s))_{t\ge s\in I} can be associated, in the space of vector-valued bounded and continuous functions, to a class of systems of elliptic operators A\bm{\mathcal A} with unbounded coefficients defined in I\times \Rd (where II is a right-halfline or I=RI=\R) all having the same principal part. We establish some continuity and representation properties of (G(t,s))tsI({\bf G}(t,s))_{t \ge s\in I} and a sufficient condition for the evolution operator to be compact in C_b(\Rd;\R^m). We prove also a uniform weighted gradient estimate and some of its more relevant consequence

    Feasibility of Graywater Systems for the Florida Environment

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    The objectives of this report was to study the existing literature and data of residential graywater treatment and disposal systems and their possible applications and environmental impacts in Florida. The report addresses mainly (1) the definition of graywater quantity and quality, (2) the evaluation of proposed graywater treatment systems for possible reuse and disposal, (3) the impact of residential graywater systems on existing and proposed wastewater treatment plants, and (4) the possible impacts on groundwater and surface water environment. The report also presents some preliminary residential graywater treatment and disposal system designs including expected treatment efficiencies and cost. It should be cautioned that the proposed designs and efficiencies are based on limited operational or test data, and a great amount of field data was obtained for blackwater septic tanks. Finally, it recommended that additional laboratory, field and operational testing is required to evaluate system design parameters and possible environmental impacts for the Florida Environment

    The socially responsible choice in a duopolistic market: a dynamic problem of “ethical product” differentiation

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    The increasing attention of profit maximizing corporations to corporate social responsibility (CSR) is a new stylized fact of the contemporary economic environment. In our theoretical analysis we model CSR adoption as the optimal response of a profit maximizing firm to the competition of a not for profit corporate pioneer in the presence of a continuum of consumers with heterogeneous preferences towards the social and environmental features of the final good. CSR adoption implies a trade-off since, on the one side, it raises production costs but, on the other side, it leads to accumulation of “ethical capital”.We investigate conditions under which the profit maximizing firm switches from price to price and CSR competition by comparing monopoly and duopoly equilibria and their consequences on aggregate social responsibility and consumer welfare. Our findings provide a theoretical background for competition between profit maximizing incumbents and not for profit entrants in markets such as fair trade, organic food, ethical banking and ethical finance

    Effect of Number of Players and Maturity on Ball-Drills Training Load in Youth Basketball

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    This study aimed to assess the basketball ball-drills workload analyzing: (1) the effect of varying the number of players involved on physiological and technical demands; (2) the temporal changes in players’ responses across bouts; and (3) the relationship of players’ workload with their maturation status and training age. Twelve young male basketball players (mean ± SD; age 13.9 ± 0.7 years; height 1.76 ± 0.06 m; body mass 65.7 ± 12.5 kg; HRmax 202 ± 8 beat·min−1) completed three bouts of 4 min interspersed by 2 min of passive recovery of two vs. two and four vs. four ball-drills. The mean percentage of HRmax (%HRmax) and ratings of perceived exertion (RPE) were collected. Technical actions (TAs) (dribbles, passes, shots, interceptions, steals, rebounds, and turnovers) were calculated through notational analysis. Players’ genitalia development (GD) and pubic hair (PH) growth were assessed using Tanner scale. Results showed a higher %HRmax (p = 0.018), RPE (p = 0.042), dribbles (p = 0.007), shots (p = 0.003), and rebounds (p = 0.006) in two vs. two compared to four vs. four condition. Furthermore, a statistical difference was found for %HRmax (p = 0.005) and number of passes (p = 0.020) between bouts. In addition, no correlation between GD, PH, and training age with %HRmax, RPE, and TAs was found. These findings suggest that variations of the number of players involved affect ball-drills workload and that ball-drills training intensity varies across bouts. Finally, ball-drills elicit an adequate training stimulus, regardless of players’ maturation status and training age

    Effects of competition level on the centre forward role of men’s water polo.

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    This study aimed to compare specific technical and tactical indicators of the team and centre forward role of Euro League, and Italian Serie A1, Serie A2, and Serie B men's water polo club competitions. A notational analysis was performed on 21 water polo matches to evaluate the occurrence of technical and tactical team and centre forward indicators, highlighting differences among championships according to chi-square analyses. Differences emerged for Counterattack (P < 0.001) and Power-Play (P < 0.001) possessions, Even (P < 0.001; Euro League: 3 ± 1, Serie A1: 3 ± 2, Serie A2: 3 ± 2, Serie B: 6 ± 4) and Power-Play (P = 0.001) goals, and exclusions and penalties (P = 0.008) of the team during Even possessions. Relatively to the role analyses, effects emerged for perimeter players playing events (P = 0.049), as well as for centre forwards' goals (P = 0.007) and exclusions and penalties (P < 0.001; Euro League: 8 ± 1, Serie A1: 6 ± 2, Serie A2: 6 ± 2, Serie B: 3 ± 2) occurring at the end of Even possessions. Therefore, in Euro League, and Italian Serie A1 and Serie A2, teams perform a high occurrence of Power-Play possessions following up an exclusion, especially achieved by the centre forward during Even possessions, while, in Italian Serie B, goals were mostly scored during Even possessions, with a relevant contribution from the centre forward rol

    Heart rate responses and technical-tactical aspects of official 5-a-side youth soccer matches played on soil and artificial turf.

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    Using a randomized crossover design, this study aimed to compare the heart rate (HR) responses and match analysis parameters (i.e., type of action; the number of players involved in an action; the number of passes performed in a collective action; precision of the shots; lost balls; ball interceptions; dribblings; and tackles) of official 5-a-side youth male soccer matches played over 2 pitch surface (i.e., clay vs. artificial turf) conditions. Twenty-two young male soccer players (age 8.3 6 0.4 years) engaged in 2 consecutive 15-minute periods in each experimental condition. During the match, 53% of HR responses exceeded 85% of the individual HRpeak. No difference emerged between both pitch surfaces and match periods for HR and match analysis indicators. The two 15-minute periods resulted in being appropriate for 8-year-old players, in resembling the intensity of play and the intermittent nature of adult soccer. The similar HR responses and technical-tactical patterns observed on the 2 surfaces indicate that youth match play is not affected by differences in pitch surface. To support the development of individual and team skills of young soccer players, coaches are advised to prioritize game knowledge based on divergent thinking and experience, rather than traditional teaching based on instructions

    Cholesterol metabolism during the growth of a rat ascites hepatoma (Yoshida AH-130).

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    The metabolism of cholesterol has been investigated in tumour cells, ascitic fluid and blood serum during the growth of an ascites hepatoma (Yoshida AH-130) in the rat. High rates of cholesterol synthesis and elevated free and esterified cholesterol content were observed in tumour cells. During tumour growth, the host animals progressively developed marked changes in the level and distribution of serum cholesterol consisting in an increase of total cholesterol and of a marked reduction of HDL cholesterol (HDL2 subfraction in particular). In agreement with previous observations, these findings indicate that a consistent pattern of altered cholesterol homeostasis develops in relation to normal or neoplastic tissue growth. High synthetic rates and intracellular accumulation of cholesterol are observed in the proliferating cells. Moreover, blood serum cholesterol decreases in the HDL fraction while it increases in LDLs, suggesting that during proliferative processes cholesterol fluxes between tissues and serum lipoproteins are markedly perturbed

    Clinical and Experimental Projects on Chemotherapy of Bladder Tumours

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    Our clinical and experimental experience with chemotherapy of bladder tumours is reviewed. The routes of drug administrations, drug dosages and combinations, are presented. Adjuvant radiotherapy and chemoprophylaxis of certain tumours are discussed.S. Afr. Med. J., 48, 631 (1974
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