856 resultados para fisk
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The existence of a new metallic carbide of composition Th(3)Ni(5)C(5) was reported in the literature in 1991. This compound is a new orthorhombic prototype structure. In this work we report a reinvestigation of the synthesis of this material and we find that the Th(3)Ni(5)C(5) compound is a new bulk superconducting material. Despite the high concentration of Ni in this compound, we find bulk superconductivity with superconducting critical temperature of T(c) = 5.0 K and an upper critical field of mu(o)H(c2) = 5.8 T. Details of the superconducting state with specific heat, magnetization, and resistivity measurements are discussed.
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In this paper, we deal with a generalized multi-period mean-variance portfolio selection problem with market parameters Subject to Markov random regime switchings. Problems of this kind have been recently considered in the literature for control over bankruptcy, for cases in which there are no jumps in market parameters (see [Zhu, S. S., Li, D., & Wang, S. Y. (2004). Risk control over bankruptcy in dynamic portfolio selection: A generalized mean variance formulation. IEEE Transactions on Automatic Control, 49, 447-457]). We present necessary and Sufficient conditions for obtaining an optimal control policy for this Markovian generalized multi-period meal-variance problem, based on a set of interconnected Riccati difference equations, and oil a set of other recursive equations. Some closed formulas are also derived for two special cases, extending some previous results in the literature. We apply the results to a numerical example with real data for Fisk control over bankruptcy Ill a dynamic portfolio selection problem with Markov jumps selection problem. (C) 2008 Elsevier Ltd. All rights reserved.
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The Polynesia Mana Node of the southeast and central Pacific contains 7 independent or autonomous countries or territories with only 6,000 km2 of land on 347 islands, but surrounded by 12 million km2 of EEZ. These seas contain 13,000 km2 of coral reefs as the main natural ecosystem providing food resources and opportunities for development, especially for tourism and pearl culture for 500,000 inhabitants. During the 19th and first half of the 20th centuries, there was major exploitation by the colonial powers of mother-of-pearl oysters for the button industry, as well as guano, sandalwood and trepang. The Polynesian people were largely involved in a subsistence economy and all coral reefs and lagoons were healthy. During the last two decades of the 20th, all countries experienced rapid development and urbanization, rising populations, and some increased agriculture. These developments were limited to a few islands of each country (i.e. 15 islands amongst the 347) with resulting degradation of the coral reefs around these sites. The other islands remained mostly uninhabited and pristine, and continued with a subsistence economy. Generally, there was more damage to the coral reefs through natural events such as cyclones and coral bleaching, than by human activities. There is however, an urgent need to combat the threats on some islands from increased sedimentation, over-fishing, dredging and nutrient pollution.
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Epilepsy is the most common serious neurological disorder and approximately 1% of the population worldwide has epilepsy. Moreover, sudden unexpected death in epilepsy (SUDEP) is the most important direct epilepsy-related cause of death. Information concerning fisk factors for SUDEP is conflicting, but potential risk factors include: young age, early onset of epilepsy, duration of epilepsy, uncontrolled seizures, seizure frequency, AED number and winter temperatures. Additionally, the cause of SUDEP is still unknown; however, the most commonly suggested mechanisms are cardiac abnormalities during and between seizures. Similarly, sudden death syndrome (SDS) is a disease characterized by an acute death of well-nourished and seeming healthy Gallus gallus after abrupt and brief flapping of their wings and incidence of SDS these animals has recently increased worldwide. Moreover, the exactly cause of SDS in Gallus gallus is unknown, but is very probable that cardiac abnormalities play a potential role. Due the similarities between SUDEP and SDS and as Gallus gallus behavioral manifestation during SDS phenomenon is close of a tonic-clonic seizure, in this paper we suggest that epilepsy could be a new possible causal factor for SDS. (C) 2009 Elsevier Ltd. All rights reserved.
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We describe the genomic organization of a recently identified CC chemokine, MIP3 alpha /CCL20 (HGMW-approved symbol SCYA20). The MIP-3 alpha /CCL20 gene was cloned and sequenced, revealing a four exon, three intron structure, and was localized by FISK analysis to 2q35-q36. Two distinct cDNAs were identified, encoding two forms of MIP-3 alpha /CCL20, Ala MLP-3 alpha /CCL20 and Ser MIP-3 alpha /CCL20, that differ by one amino acid at the predicted signal peptide cleavage site. Examination of the sequence around the boundary of intron 1 and exon 2 showed that use of alternative splice acceptor sites could give rise to Ata MIP-3 alpha /CCL20 or Ser MIP-3 alpha /CCL20. Both forms of MIP-3cr/CCL20 were chemically synthesized and tested for biological activity. Both flu antigen plus IL-a-activated CD4(+) and CD8(+) T lymphoblasts and cord blood-derived dendritic cells responded to Ser and Ala MIP-3 alpha /CCL20. T lymphocytes exposed only to IL-2 responded inconsistently, while no response was detected in naive T lymphocytes, monocytes, or neutrophils. The biological activity of Ser MIP-3 alpha /CCL20 and Ala MIP-3 alpha /CCL20 and the tissue-specific preference of different splice acceptor sites are not yet known. (C) 2001 Academic Press.
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Lorsqu'un individu est confronté à une situation stressante, une des réponses les plus saillantes est l'activation de l'axe HPA, caractérisée par le déclenchement d'un taux élevé de glucocorticoïdes dans le sang. De manière générale, cette réponse hormonale est adaptative et elle a pour but la mobilisation des ressources physiques et cognitives de l'individu pour une action spécifique (Axelrod & Reisine, 1984; Chrousos & Gold, 1992; N. M. Kaplan, 1988; McEwen, 2004). Cependant, lorsque une personne est confrontée très tôt dans son développement, et de manière répétée, à des situations de stress, cette réponse physiologique peut s'altérer, devenir inadaptée (Anand, 1993; Bremner et al., 1995; Meaney et al., 1996; Mirescu, Peters, & Gould, 2004; Plotsky & Meaney, 1993; Sapolsky, 2000) et être associée à des troubles cognitifs (McEwen & Sapolsky, 1995) et émotionnels (McEwen, 2000). A l'âge adulte, le résultat de ces altérations psychoneuroendocriniennes se traduit au cours de l'activation de l'axe HPA et elles sont visibles lors de situations de stress moins intenses (Graham, Heim, Goodman, Miller, & Nemeroff, 1999; Mirescu et al., 2004; Stam, Bruijnzeel, & Wiegant, 2000; A. Taylor, Fisk, & Glover, 2000). La dysregulation de l'axe HPA semble représenter un facteur de vulnérabilité lié à des dysfonctionnements psychiques et physiologiques chez les adultes (Heim, Ehlert, & Hellhammer, 2000; Heim & Nemeroff, 1999; Heim, Newport, Mletzko, Miller, & Hemeroff, 2008). Cependant, des facteurs de protection peuvent influencer à leur tour ces vulnérabilités. La littérature, basée sur des études translationnelles (animaux, humains), converge vers le postulat selon lequel la dimension relationnelle apportée par l'environnement est fondamentale dans le développement des vulnérabilités physiologiques et psychiques du sujet. Dans ce sens, les relations d'attachement ont été particulièrement étudiées. A l'âge adulte, par exemple, la qualité des représentations d'attachement semble influencer directement l'expression de gènes impliqués dans les réponses hormonales de stress (Biagini, Pich, Carani, Marrama, & Agnati, 1998; Caldji, Diorio, & Meaney, 2000; Dallman, 2000; De Kloet, Rosenfeld, Van Eekelen, Sutanto, & Levine, 1988; Rincon-Cortes & Sullivan, 2014; Romeo, Tang, & Sullivan, 2009; van Oers, de Kloet, Whelan, & Levine, 1998), illustrant ainsi une perspective épigénétique. Traumatismes précoces et réponses de stress, leur association avec la santé mentale, l'attachement et l'ocytocine Deux objectifs principaux définissent ce travail de doctorat. Le premier est de comprendre comment un événement à portée traumatique, qui a eu lieu pendant la période périnatale, l'enfance ou l'adolescence, peut s'inscrire au niveau physiologique (axe hypotalamico- hypophysaire-surrénalien - axe HPA), au niveau psychopathologique ou encore au niveau de la régulation émotionnelle au cours de l'âge adulte. A ce propos, nous avons évalué les réponses physiologiques (telles que le Cortisol, l'ACTH et l'ocytocine), la présence de psychopathologies (relatives à l'axe I du DSM-IV) et les réponses émotionnelles (telles que la perception au stress) au cours d'une situation de stress de nature psychosociale, induite en laboratoire. Le deuxième objectif de ce travail est de savoir si les représentations d'attachement peuvent médiatiser ces effets, chez des individus exposés à différents événements à portée traumatique. Dans ce but, trois populations ont été considérées. La première est relative à des jeunes adultes nés grands prématurés ; la deuxième, concerne des femmes adultes ayant vécu un ou plusieurs abus sexuels au cours de leur enfance ou de leur adolescence et enfin la troisième est constituée de personnes adultes qui ont survécu à une maladie grave (cancer) pendant leur enfance ou leur adolescence. Enfin, ces trois populations sont comparées à des groupes contrôle. La prise en considération de différents types de traumatismes a permis de relever : premièrement, qu'un événement à portée traumatique de nature différente, peut influencer de manière semblable les structures neuronales, par exemple l'hypocortisolémie ; deuxièmement, qu'un dysfonctionnement de l'axe HPA n'aboutit pas nécessairement à la présence de signes de souffrance mentale ; enfin, des effets protecteurs ont été mis en évidence. Ces facteurs sont sous-tendus, d'un point de vue psychologique, par les représentations d'attachement et, d'un point de vue physiologique, par la sécrétion d'ocytocjne périphérique. Traumatismes précoces et réponses de stress, leur association avec la santé mentale, l'attachement et l'ocytocine -- When an individual is faced by a stressful situation, one of the most notable responses is the activation of the HPA axis, which is characterized by a heightened level of glucocortisoids in the blood. In general, this is an adaptive hormonal response which prepares the individual both physically and cognitively for a specific action (Axelrod & Reisine, 1984; Chrousos & Gold, 1992; N. M. Kaplan, 1988; McEwen, 2004). However, should a person be confronted to stressful situations very early and repeatedly in their development, this physiologic response may be altered and become maladapted (Anand, 1993; Bremner et al., 1995; Meaney et al., 1996; Mirescu et al., 2004; Plotsky & Meaney, 1993; Sapolsky, 2000) which can be associated to emotional (McEwen, 2000) and cognitive disorders(McEwen & Sapolsky, 1995). Throughout adulthood, the result of these psychoneuroendocrine alterations affects the activation of the HPA axis and are noticeable during less intense stressful situations (Graham et al., 1999; Mirescu et al., 2004; Stam et al., 2000; A. Taylor et al., 2000). HPA axis dysregulation appears to represent a factor of vulnerability linked to psychological and physical disorders in adults (Heim, Ehlert, et al., 2000; Heim & Nemeroff, 1999; Heim, Newport, et al., 2008). Nonetheless, these vulnerabilities may be influenced by further protection factors. The literature, based on translational studies (animals and humans), suggests that relationships formed in the context of the individual's environment are fundamental in the development of their physiological and psychological vulnerabilities. Thus, attachment relationships have been particularly studied. In adulthood, for example, the quality of attachment representations appear to influence directly the expression of genes involved in the hormonal responses to stress (Biagini et al., 1998; Caldji et al., 2000; Dallman, 2000; De Kloet et al., 1988; Rincon-Cortes & Sullivan, 2014; Romeo et al., 2009; van Oers et al., 1998). With the goal to study these dimensions, two principal objectives define these doctoral study. The first is to understand how an event considered to be traumatic, which took place during early infancy, infancy, or adolescence, could influence physiology (HPA axis), psychopathology or emotional regulation during adulthood. Therefore we have evaluated the presence of psychopathologies (relative to axis I of the DSM), physiological responses (such as Cortisol, ACTH and oxytocin) and emotional responses (such as perception of stress) throughout a psychosocial stress situation, conducted in a laboratory setting. The second objective of this study is to understand if attachment representations can mediate these effects, in individuals exposed to three different types of traumatic events. Therefore, three populations have been considered. The first is young adults who were born prematurely; the second concerns adult women who have suffered sexual abuse, on one or more occasions, during their childhood or adolescence; finally the third group is constituted of people who have survived a grave childhood illness. These populations were all compared to control groups. The consideration of different types of traumatic events has demonstrated, firstly, that different events which are considered to be traumatic can similarly influence neuronal structures, for example hypocortisolism. Secondly, that an HPA axis disorder does not necessarily lead to the presence of mental signs of distress, as is the case for those born very prematurely. Finally, protective effects were demonstrated, distinctively from a psychological point of view, by attachment representations and furthermore by peripheral oxytocin secretion from a physiological perspective.
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Hormonstörande ämnen är syntetiska eller naturliga ämnen som stör organismers hormonsystem och bidrar till könsförvirring och sterilitet. Sådana ämnen kommer i ökande takt ut i vattenmiljön genom rester av läkemedel, bekämpningsmedel och industriprodukter. Eftersom det finns många likheter mellan hormonsystemen hos människan och övriga ryggradsdjur kan till exempel fiskar användas som modellsystem för att underöka detta problem. I tidigare undersökningar har man funnit hormonella störningar, bl.a. feminisering och maskulinisering hos fiskar som utsatts för avfallsvatten från kommunala reningsverk eller avfallsvatten från pappersindustrin. Målet med denna avhandling var att undersöka om renat avfallsvatten från kommunala reningsverk längs Finlands kust innehåller hormonstörande ämnen i sådana mängder att de kan försorsaka hormonstörande effekter på fisk. Målet i denna avhandling var också att utveckla cellulära testsystem baserade på fiskceller, eftersom behovet av tillförlitliga och kostnadseffektiva cellbaserade tester för att underlätta riskbedömningen av hormonstörande ämnen är mycket stort för tillfället. Som testsystem har storspiggen använts, som besitter flera användbara biomarkörer för att mäta hormonstörande ämnens påverkan. Resultaten tyder på att problemen med hormonstörande påverkan på fisk inte är lika utbredda i Finland som i många andra europeiska länder. Detta beror troligtvis på att finska reningsverk har effektiva reningstekniker som reducerar mängden hormonstörande ämnen, eller på att utspädningen av avloppen i recipienterna är större än i många andra länder. Dock kan problemen inte helt uteslutas eftersom vissa feminiserande (estrogena) effekter kunde observeras hos fisken i de undersökta recipienterna utanför kommunala reningsverk. I kontrollerade laboratorieförsök där storpsiggar exponerades för kommunalt avloppsvatten uppmättes även här effekter som tyder på förekomst av estrogener i avloppsvattnet. De cell-baserade testsystemen klarade av att förutspå hormonella effekter hos hel fisk och kan därför vara mycket användbara i fortsatta studier av hormonstörande ämnens verkningsmekanismer i preliminära toxicitetsbedömningar.
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Målet for vannforvaltning er å opprettholde god tilstand i vann og forbedre tilstanden i vann der hvor den er svekket. Det pågår en andre planleggingsrunde i vannforvaltning. Under denne runden skal planene kontrolleres og vannforvaltningsplaner frem til 2021 utarbeides. Vannregionen Tana-Neiden-Pasvik på finsk side strekker seg også til norske og russiske områder og planene skal koordineres. Dette dokumentet inneholder planlagt arbeidsprogram og sentrale spørsmål for vannregionen på finsk side. Dokumentet sendes på høring fra 15. juni til 17. desember 2012. Til hjelp i planleggingen ønskes blant annet tilbakemelding om gjennomføring og tidsplan for planlegging og påvirkningsmuligheter; saker knyttet til utarbeiding av miljøredegjørelse og innhold; sentrale problemer og utviklingsbehov for vanntilstand; midler og tiltak for å kunne bedre tilstanden til vann og muligheter for finansiering og samarbeid. Endringer i virksomhetsmiljøet påvirker definering og vektlegging av sentrale spørsmål for andre planperiode. Ny lovgivning har kommet til og det er etter første planrunde blitt gjennomført eller startet flere nye programmer og strategier som påvirker vannforvaltning. Det kan nevnes f.eks. vannforbedringsstrategi og strategi for vandringsveier for fisk. Det skal åpnes nye gruver i vannregionen. De største endringene er kommet som følge av gruvedriften på russisk side av Pasvikelva. Innstramninger i statsøkonomien reduserer finansieringsmulighetene til vannforvaltning for offentlig sektor. For eksempel forutsetter videre arbeid med vassdragsrehabilitering i fremtiden at man klarer å knytte nye aktører til det. Sentrale spørsmål for vannforvaltning i vannregionen Tana-Neiden-Pasvik er knyttet til forbedring av vannforsyning for boligområder og vern av grunnvann; håndtering av vassdragsbelastning; reduksjon av ulemper ved vassdragsutbygging og regulering; forebygging av spredning av fremmede arter og fiskesykdommer og utarbeiding av målsettinger for vannforvaltning og håndtering av flomrisiko. Mer informasjon om vannforvaltning på nettadressen: www.ymparisto.fi/lap/vesienhoito.
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kuv., 14 x 22 cm
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15 x 10 cm
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kuv., 10 x 17 cm
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kuv., 10 x 17 cm
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kuv., 10 x 17 cm
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kuv., 10 x 17 cm
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kuv., 10 x 17 cm