937 resultados para few-body problems


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Aircraft pursuit-evasion encounters in a plane with variable speeds are analysed as a differential game. An engagement-dependent coordinate system confers open-loop optimality on the game. Each aircraft's optimal motion can be represented by extremel trajectory maps which are independent of role, adversary and capture radius. These maps are used in two different ways to construct the feedback solution. Some examples are given to illustrate these features. The paper draws on earlier results and surveys several existing papers on the subject.

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OBJECTIVE To monitor the seasonal body composition alterations in 18 lightweight rowers (six females, 12 males) across a rowing season incorporating preseason, early competition, competition, and postseason. METHODS Subject age was 23.1 (SD 4.5) years, height 170.8 (5.6) cm (female, 23.5 (3.5) years, 180.5 (2.7) cm (male). Body weight, fat mass, and fat-free mass (FFM) were assessed using dual energy x ray absorptiometry (DXA-L Lunar) and skinfold techniques. Weight control techniques were documented before major regattas by a questionnaire. RESULTS Female body weight was reduced from 61.3 (2.9) to 57.0 (1.1) kg (5.9%), while male body weight was reduced from 75.6 (3.1) to 69.8 (1.6) kg (7.8%) preseason to competition season respectively. These body weight reductions were mirrored by a significant reduction in fat mass as indicated by the sum of skinfolds [female seven sites: 80.9 (8.1) to 68.2 (11.8) mm; male eight sites: 54.2 (8.7) to 41.8 (4.8) mm], percentage body fat [female 22.1 (1.0) to 19.7 (2.4)%; male 10.0 (0.9) to 7.8 (0.8)%], and total fat [female 12.5 (5.2) to 10.9 (1.4) kg; male 7.3 (1.9) to 5.6 (1.8) kg] (DXA). In contrast, no changes were observed in FFM despite a season of intensive rowing training. Seasonal body weight control was achieved through reduced total energy and dietary fat intakes. Acute body weight reductions were achieved by exercise in 73.3% of participants, food restriction in 71.4%, and fluid restrictions in 62.9%. CONCLUSIONS Seasonal body weight alterations in lightweight rowers are in response to a significant reduction in fat mass. However, the weight restrictions appear to be limiting an increase in FFM which could be beneficial to rowing performance.

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The response of cattle to alterations in social groupings can lead to physiological changes that affect meat quality. Feedlot practices frequently lead to a proportion of cattle in a pen being drafted for slaughter with the balance retained for a further period until they meet market specifications. An ability to regroup such retained cattle for short periods without consequences for meat quality would facilitate efficient use of feedlot pen space. The current experiment examined the impact on physiological variables and meat quality of regrouped British breed steers 4, 2 or 1 week before dispatch for slaughter. There was little effect of regrouping cattle on physiological variables associated with stress responses. Physical assessment of meat quality indicated that regrouping steers 1 week before slaughter led to higher compression and a tendency for higher peak force values in animals from one genotype than in their respective controls (1.89 v. 1.71 ± 0.05 kg, P = 0.017); however, these assessments were not matched by changes in sensory perception of meat quality. Average daily gain during feedlot finishing was negatively related to the temperament measure and flight time. It was also associated with breed, white cell count, plasma cortisol and haemoglobin at the midpoint of the 70-day finishing period. The results confirm the impact of flight time on growth rate during feedlot finishing and that regrouping cattle less than 2 weeks before slaughter may reduce meat quality.

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Although the majority of people with mental illness are not violent, scientific studies over the last decades show that certain psychiatric disorders increase the risk of violent behavior, including homicide. This thesis examined crime scene behaviors and offender background characteristics among mentally ill Finnish homicide offenders. Previously, homicide crime scene behaviors have been investigated in relation to offender demographic characteristics, whereas this study compares the behaviors of offenders with various mental illnesses. The study design was a retrospective chart review of the forensic psychiatric statements of Finnish homicide offenders. The work consists of four substudies. The aims of the study were as follows: To describe differences in the childhood and family backgrounds as well as in the adolescent and adult adjustment of Finnish homicide offenders belonging to different diagnostic categories (schizophrenia, personality disorder, alcoholism, drug addiction or no diagnosis). Further, the study examined associations between the crime scene behaviors and mental status of these offenders. Also, the distinguishing characteristics between two groups of offenders with schizophrenia were examined: early starters, who present antisocial behavior before the onset of schizophrenia, and late starters, who first offend after the onset of mental disorder. Finally, it was investigated how the use of excessive violence is associated with clinical and circumstantial variables as well as offender background characteristics among homicide offenders with schizophrenia. The main findings of the study can be summarized as follows. First, offenders with personality disorder or drug addiction had experienced multiple difficulties in their early environments: both family and individual problems were typical. Offenders with schizophrenia were relatively well-adjusted in childhood compared to the other groups. However, in adolescence and adulthood, social isolation, withdrawal and other difficulties attributable to these offenders illness became evident. In several aspects, offenders with alcohol dependency resembled offenders with no diagnosis in that these offenders had less problematic backgrounds compared to other groups. Second, the results showed that crime scene behaviors, victim gender and the victim-offender relationship differ between the groups. In particular, offenders with a diagnosis of schizophrenia or drug addiction have some unique features in their crime scene behaviors and choice of victims. Offenders with schizophrenia were more likely to kill a blood relative, to use a sharp weapon and to injure the victim s face. Drug addiction was associated with stealing from the victim and trying to cover up the body. Third, the results suggest that the offense characteristics of early- and late-start offenders with schizophrenia differ only modestly. However, several significant differences between the groups were found in characteristics of offenders: early starters had experienced a multitude of problems in their childhood surroundings and also later in life. Fourth, violent acts where the offender did not commit the offense alone or had previous homicidal history were predictive of excessive violence among offenders with schizophrenia. Positive psychotic symptoms did not predict the use of excessive violence. Nearly one third of the cases in the sample involved multiple and severe violence, including features such as sadism, mutilation, sexual components or extreme stabbing. In sum, mentally disordered homicide offenders are heterogeneous in their offense characteristics as well as their background characteristics. Empirically based information on how the offender s mental state is associated with specific crime scene behaviors can be utilized within the police force in developing methods of prioritizing suspects in unsolved homicide cases. Also, these results emphasise the importance of early interventions for problem families and children at risk of antisocial behavior. They may also contribute to the development of effective treatment for violent offenders.

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This Article examines the adverse impact theory of employment discrimination under Title VII. The author begins by discussing the development of adverse impact in the case law, and by scrutinizing its theoretical underpinnings. He demonstrates that Congress did not intend to mandate adoption of adverse impact theory when it established Title VII. The author then argues that the Courts have exceeded their authority under Title VII by embracing the theory of adverse impact. He concludes that the courts should therefore return to a narrower theory of employment discrimination, namely, a theory based on the legal concept of “intent.”

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A total of 2115 heifers from two tropical genotypes (1007 Brahman and 1108 Tropical Composite) raised in four locations in northern Australia were ovarian-scanned every 4-6 weeks to determine the age at the first-observed corpus luteum (CL) and this was used to de. ne the age at puberty for each heifer. Other traits recorded at each time of ovarian scanning were liveweight, fat depths and body condition score. Reproductive tract size was measured close to the start of the first joining period. Results showed significant effects of location and birth month on the age at first CL and associated puberty traits. Genotypes did not differ significantly for the age or weight at first CL; however, Brahman were fatter at first CL and had a small reproductive tract size compared with that of Tropical Composite. Genetic analyses estimated the age at first CL to be moderately to highly heritable for Brahman (0.57) and Tropical Composite (0.52). The associated traits were also moderately heritable, except for reproductive tract size in Brahmans (0.03) and for Tropical Composite, the presence of an observed CL on the scanning day closest to the start of joining (0.07). Genetic correlations among puberty traits were mostly moderate to high and generally larger in magnitude for Brahman than for Tropical Composite. Genetic correlations between the age at CL and heifer- and steer-production traits showed important genotype differences. For Tropical Composite, the age at CL was negatively correlated with the heifer growth rate in their first postweaning wet season (-0.40) and carcass marbling score (-0.49), but was positively correlated with carcass P8 fat depth (0.43). For Brahman, the age at CL was moderately negatively genetically correlated with heifer measures of bodyweight, fatness, body condition score and IGF-I, in both their first postweaning wet and second dry seasons, but was positively correlated with the dry-season growth rate. For Brahman, genetic correlations between the age at CL and steer traits showed possible antagonisms with feedlot residual feed intake (-0.60) and meat colour (0.73). Selection can be used to change the heifer age at puberty in both genotypes, with few major antagonisms with steer- and heifer- production traits.

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Working life is changing. The core of the change is change in the production and service concepts of organizations. Changes at work are connected to problems in the well-being of employees. To respond to this challenge, occupational health care must develop a course of action. A group of occupational health care units has developed new activity theory-based methods, the object of which is to change the service concept of occupational health care. The focus is on the changes and disturbances in work activity. My aim was to study this development from the perspective of knowledge management; to clarify directors'/ managers' conceptions of the content and object of their managerial work and the tensions included in these conceptions; to examine the learning process involved in these methods and to bring to light the problems, developmental needs and challenges during the implementation and consolidation phases of the process. This was a case study which included 10 occupational health care units using or being trained to use activity theory-based methods. My data consisted of interviews with directors/managers and recordings of the meetings; 20 directors/ managers are represented; I interviewed seven directors/ managers who represented four units. Directors'/ managers' conceptions of the content and object of managerial work were divided into eight categories of description, which I connected to the historical forms of organizations and types of management. Intuitive and rational management are historically older forms of management. The categories of description representing intuitive and rational management contained many internal tensions, i.e. they do not satisfy the demands of the environment. On the other hand, the categories of description which represented management by results and the control of the development process contained very few or no tensions at all; they are effective in the present environment of occupational health care. The learning process of activity theory-based methods has been expansive in nature. The occupational health care units studied are in different phases of the learning process, and these processes have been different. In three units the focus was on work development; in one unit the focus was on development of the service concept. The most central problems, challenges and developmental needs during the implementation phase were related to learning and spreading of methods inside one's own unit, and during the consolidation phase to working with partners.

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Objectives. The purpose of this study was to examine perceptions of evaluation of learning and feedback among teachers and students of mechanical engineering at the Helsinki University of Technology. The differences and similarities between the perceptions of these two groups were also studied. Course feedback was examined, and a target was set to rationalize the collation and exploitation of the feedback data. The theoretical background for the evaluation of learning was based primarily on the theories of Brown (1997), Karjalainen (2001) and Rowntree (1977, 1988). The Biggs (2003) model on aligned teaching was used as an example of quality university education. Feedback practices were examined through the theory of Ramsden (1992) and many recent research articles. Methods. The qualitative study was executed by examining the evaluation of learning and feedback prac-tices of the courses in mechanical engineering at the Helsinki University of Technology. The data was gathered by interviewing the teachers responsible of basic and postgraduate studies, as well as students taking their basic studies. Four group interviews were arranged for both teachers and students, each with three participants. The data from these themed interviews were analyzed by means of content analysis. Result and conclusions. This study showed that teachers and students have similar perceptions of evalua-tion of learning and feedback excluding a few significant differences. The most essential difference in evaluation of learning was that students perceived the evaluation of the examinations to be inaccurate. Teachers on the other hand thought that the existing practice for the exam evaluation is working fine. Stu-dents also felt that they are not giving enough information on the opportunities to get feedback. Teachers instead expected students to actively ask for feedback. Students perceived the need for exploiting the course feedback for course development purposes more than before. Teachers saw foremost the challenges and problems in the exploitation of the feedback. In the future, more effort must be put on the research of the evaluation of learning and feedback, as the quality assurance and continuous improvement of the teaching calls for new data.

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The problem of learning correct decision rules to minimize the probability of misclassification is a long-standing problem of supervised learning in pattern recognition. The problem of learning such optimal discriminant functions is considered for the class of problems where the statistical properties of the pattern classes are completely unknown. The problem is posed as a game with common payoff played by a team of mutually cooperating learning automata. This essentially results in a probabilistic search through the space of classifiers. The approach is inherently capable of learning discriminant functions that are nonlinear in their parameters also. A learning algorithm is presented for the team and convergence is established. It is proved that the team can obtain the optimal classifier to an arbitrary approximation. Simulation results with a few examples are presented where the team learns the optimal classifier.

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The parenthood experience of a mother with a disabled child and the meaning of the social environment and parent-professional partnerships The importance of parental guidance when a family has a child with a disability or autism has been pointed out by several studies. The present research was based on the premise that by supporting the mother we can help the whole family to cope better and the professionals in day care or at school are able to support parents. The starting point was the subjective experience, which is also the central focus of the phenomenological method. The purpose of this study was firstly to describe the experience of the mother and the dialogue between mother and educational professionals. Secondly it was the task of this research to discover what kind of support and information the mother obtains from her social environment. At the background of this study there was the ecological theory of Bronfenbrenner, the ecocultural approach by Gallimore and the interactive examination of family that take into consideration the whole environment and personal situation. The research data was collected by interviewing the mothers, the day care personnel and the teachers at school. In this research there were a total of 32 interviews and 24 informants: 10 mothers who have a child with a disability and/or autism, 8 professionals in day care and 6 teachers at school. This study was longitudinal because the same mothers were interviewed twice, first in 1998 and then after five years in 2003. It was thus possible to get information on whether their life situation had changed and the nature of those changes. The data of this study was analysed by the method of phenomenological psychology that was applied for this study. The findings indicated that all mothers had experienced many complicated emotional feelings such as: anger, mourning, fear and sadness as well as love and bonding. It can be said that several human feelings existed at the same time. Mothers experienced that the support of the social environment, for example, relatives, families in the same situation and persons taking care of the child had significant meaning for their coping. However the life situation among the mothers varied. Mostly mothers received valuable support for their parenthood and they have adopted a strong emotion for manage ring. Mothers with an autistic child were more stressed than mothers with a mentally retarded child. A few mothers had numerous problems with taking care of their child and they did not get enough help. Same mothers were very exhausted too and the situation was quite the same after five years, when their child was teenager. All mothers said that after starting school the support for the family had significally diminished. Mothers said that dialogue with teacher got on without problems, but there were meetings seldom, so it wasn´t possible to get enough support for their parenthood. Keywords: parenthood, motherhood, disability, early special education, family-centred.

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Historically, determining the country of origin of a published work presented few challenges, because works were generally published physically – whether in print or otherwise – in a distinct location or few locations. However, publishing opportunities presented by new technologies mean that we now live in a world of simultaneous publication – works that are first published online are published simultaneously to every country in world in which there is Internet connectivity. While this is certainly advantageous for the dissemination and impact of information and creative works, it creates potential complications under the Berne Convention for the Protection of Literary and Artistic Works (“Berne Convention”), an international intellectual property agreement to which most countries in the world now subscribe. Under the Berne Convention’s national treatment provisions, rights accorded to foreign copyright works may not be subject to any formality, such as registration requirements (although member countries are free to impose formalities in relation to domestic copyright works). In Kernel Records Oy v. Timothy Mosley p/k/a Timbaland, et al. however, the Florida Southern District Court of the United States ruled that first publication of a work on the Internet via an Australian website constituted “simultaneous publication all over the world,” and therefore rendered the work a “United States work” under the definition in section 101 of the U.S. Copyright Act, subjecting the work to registration formality under section 411. This ruling is in sharp contrast with an earlier decision delivered by the Delaware District Court in Håkan Moberg v. 33T LLC, et al. which arrived at an opposite conclusion. The conflicting rulings of the U.S. courts reveal the problems posed by new forms of publishing online and demonstrate a compelling need for further harmonization between the Berne Convention, domestic laws and the practical realities of digital publishing. In this chapter, we argue that even if a work first published online can be considered to be simultaneously published all over the world it does not follow that any country can assert itself as the “country of origin” of the work for the purpose of imposing domestic copyright formalities. More specifically, we argue that the meaning of “United States work” under the U.S. Copyright Act should be interpreted in line with the presumption against extraterritorial application of domestic law to limit its application to only those works with a real and substantial connection to the United States. There are gaps in the Berne Convention’s articulation of “country of origin” which provide scope for judicial interpretation, at a national level, of the most pragmatic way forward in reconciling the goals of the Berne Convention with the practical requirements of domestic law. We believe that the uncertainties arising under the Berne Convention created by new forms of online publishing can be resolved at a national level by the sensible application of principles of statutory interpretation by the courts. While at the international level we may need a clearer consensus on what amounts to “simultaneous publication” in the digital age, state practice may mean that we do not yet need to explore textual changes to the Berne Convention.

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The subject of my research was analyzing how psychological violence appears in educational communities in both preschool and kindergarten environments. The superiors of every daycare unit (a total of 80 units) in Vantaa were asked to tell about their own views and experiences of psychological violence in educational communities. In addition I cleared out the superior’s views on what the role of workplace counseling is in clearing out cases of psychological violence. A workplace always consists of people connected through work and the workplace creates a context for psychological violence. Working is public in an educational environment, as also customers set expectations and make wishes on how the work should be done. Different thoughts on what the working community should be creates pressure for the workers. My aim was to find out about the superior’s views on different types of psychological violence in the workplace, how one’s personality effects on an experience on psychological violence, the superior’s abilities and possibilities on noticing psychological violence in an early stage and the necessity of intervention. I also wanted to map the superior’s views and experiences on the value of workplace counseling in straightening out cases of psychological violence. The research point of view used was triangulation with hermeneutical and phenomenological features. The research method used was a semistructured questionnaire with a few open questions used to seek answers for the problems that have come up in the research. I analyzed the collected data partly from quantitative and partly from qualitative point of views, and also my aim was to understand psychological violence in the workplace as a phenomena in the communities within the early phases of education and to give this worker-to-worker mobbing a face. As a result of my research, I found out that the psychological violence inside the educational communities is more passive and scheming than aggressive or straightforward. The most important outcome of my research was finding a risk factor, where the superior is in danger of being the target of workplace psychological violence. Out the superiors who answered the questionnaire, 12% told they had been the target of this psychological violence after being transferred in to an old unit to work as the new superior. I hope this result will be of use when changes similar to this are known to take place. Avainsanat – Nyckelord – Keywords Psychological violence, educational enviroment, moral and ethic at work, role of the superior, role of a workplace consultant

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Promotion of better procedures for releasing undersize fish, advocacy of catch-and-release angling, and changing minimum legal sizes are increasingly being used as tools for sustainable management of fish stocks. However without knowing the proportion of released fish that survive, the conservation value of any of these measures is uncertain. We developed a floating vertical enclosure to estimate short-term survival of released line-caught tropical and subtropical reef-associated species, and used it to compare the effectiveness of two barotrauma-relief procedures (venting and shotline releasing) on red emperor (Lutjanus sebae). Barotrauma signs varied with capture depth, but not with the size of the fish. Fish from the greatest depths (40-52 m) exhibited extreme signs less frequently than did those from intermediate depths (30-40 m), possibly as a result of swim bladder gas being vented externally through a rupture in the body wall. All but two fish survived the experiment, and as neither release technique significantly improved short-term survival of the red emperor over non-treatment we see little benefit in promoting either venting or shotline releasing for this comparatively resilient species. Floating vertical enclosures can improve short-term post-release mortality estimates as they overcome many problems encountered when constraining fish in submerged cages.

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n recent years, fuel cell technology has advanced significantly. Field trials on certain types of fuel cells have shown promise for electrical use. This article reviews the electrochemistry, problems and prospects of fuel cell systems.

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The unsteady laminar compressible three-dimensional stagnation-point boundary-layer flow with variable properties has been studied when the velocity of the incident stream, mass transfer and wall temperature vary arbitrarily with time. The second-order unsteady boundary-layer equations for all the effects have been derived by using the method of matched asymptotic expansions. Both nodal and saddle point flows as well as cold and hot wall cases have been considered. The partial differential equations governing the flow have been solved numerically using an implicit finite-difference scheme. Computations have been carried out for an accelerating stream, a decelerating stream and a fluctuating stream. The results indicate that the unsteady free stream velocity distributions, the nature of the stagnation point, the mass transfer, the wall temperature and the variation of the density-viscosity product across the boundary significantly affect the skin friction and heat transfer. The variation of the wall temperature with time strongly affects the heat transfer whereas its effect is comparatively less on skin friction. Suction increases the skin friction and heat transfer but injection does the opposite. The skin friction in the x direction due to the combined effects of first- and second-order boundary layers is less than the skin-friction in the x direction due to the first-order boundary layers for all the parameters. The overall skin friction in the z direction and heat transfer are more or less than the first-order boundary layers depending upon the values of the various parameters.