1,722 research outputs found

    Update on tests of the Cen A neutron-emission model of highest energy cosmic rays

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    We propose that neutron emission from Cen A dominates the cosmic ray sky at the high end of the spectrum. Neutrons that are able to decay generate proton diffusion fronts, whereas those that survive decay produce a spike in the direction of the source. We use recent data reported by the Pierre Auger Collaboration to normalize the injection spectrum and estimate the required luminosity in cosmic rays. We find that such a luminosity, L_{CR} ~ 5 x 10^{40} erg/s, is considerably smaller than the bolometric luminosity of Cen A, L_{bol} ~ 10^{43} erg/s. We compute the incoming current flux density as viewed by an observer on Earth and show that the anisotropy amplitude is in agreement with data at the 1\sigma level. Regardless of the underlying source model, our results indicate that after a decade of data taking the Pierre Auger Observatory will be able to test our proposal.Comment: To be published in PR

    Labour co-determination and corporate governance in Germany: The economic impact of marginal and symbolic rights

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    For decades, some governments have fiercely opposed any statute of the Societas Europaea that foresaw German-type co-determined supervisory boards. Considering firms as pools of specific investors, we ask about the conditions that are necessary to secure the interests of specific human capitalists in an efficient way, if the real capital owners' right to residual control does not solve the ex-post bargaining problems over the sharing of quasi-rents. We disregard contract-theoretic approaches as solutions to the ex-post bargaining conflicts and suggest a constitutional approach to this major problem in the theory of the firm. From a constitutional perspective, the (non-executive) board members of the German Aufsichtsrat (Supervisory Board) - unlike the Betriebsrat (Works Council) - essentially dispose only of marginal, extremely symbolic, i.e., non-enforceable rights to represent worker investors. Legally, however, these rights are to be used first in the interests of the corporation and only secondarily in the interests of partial investors. Marginal and symbolic rights as well as fiduciary duties will make a difference in distributive bargaining, if they are legally imposed. Who is to be heard and to be involved in decision-making and what is counted as a legitimate argument or action - these are basically questions of political culture that in principle leave room for efficient international diversity. Option rights in the European directive on the Societas Europaea should thus be considered as an apt and wise decision. -- Seit Jahrzehnten wehren sich einige Regierungen vehement gegen die Schaffung einer Societas Europaea, welche mitbestimmte Aufsichtsr√§te nach deutschem Muster f√ľr europ√§ische Aktiengesellschaften erm√∂glicht. Indem wir Firmen als Zusammenschluss spezifischer Investoren betrachten, fragen wir nach notwendigen Bedingungen, um die Interessen spezifischer Humankapitalgeber effizient abzusichern, wenn das residuale Kontrollrecht der Finanzkapitalgeber Ex-post-Verhandlungsprobleme √ľber die Aufteilung der Quasirenten nicht zu l√∂sen vermag. Wir sehen von vertragstheoretischen L√∂sungsans√§tzen zu Ex-post-Verhandlungsproblemen ab und empfehlen vielmehr eine konstitutionelle Ann√§herung an dieses Hauptproblem der Unternehmenstheorie. Aus konstitutioneller Sicht verf√ľgen Arbeitnehmervertreter im Aufsichtsrat - im Gegensatz zum Betriebsrat - lediglich √ľber marginale und eher symbolische, d.h. nicht die Interessen der Arbeitnehmerschaft zwingend durchsetzbare Rechte. Aus juristischer Sicht wiederum sollen diese Recht in erster Linie im Interesse des Unternehmens und erst nachrangig zur Durchsetzung von Partialinteressen verschiedener Investorengruppen genutzt werden. Marginale und symbolische Rechte ebenso wie treuh√§nderische Pflichten ver√§ndern die Ergebnisse von Verteilungsverhandlungen, wenn diese Rechte gesetzlich verankert sind. Wer muss geh√∂rt oder in den Entscheidungsprozess mit eingebunden werden und was gilt als legitimes Argument oder legitime Handlung - dies sind im Grunde Fragen der politischen Kultur, die im Prinzip Raum f√ľr effiziente internationale Vielfalt lassen. Optionsrechte in der europ√§ischen Direktive der Societas Europaea sollten infolgedessen als angemessene und weise Entscheidung angesehen werden.

    IT at the FHI ‚ÄúEnabling Science‚ÄĚ

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    Processamento do milho em ra√ß√Ķes de frangos de corte: desempenho e digestibilidade

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    TCC (gradua√ß√£o) - Universidade Federal de Santa Catarina. Centro de Ci√™ncias Agr√°rias. Curso de Zootecnia.A busca por t√©cnicas que promovam aumento na utiliza√ß√£o dos nutrientes fez com que as t√©cnicas de processamento de ra√ß√£o, como peletiza√ß√£o e expans√£o, ganhassem maior aten√ß√£o dos nutricionistas. A estas pr√°ticas s√£o atribu√≠dos alguns benef√≠cios no desempenho produtivo e na otimiza√ß√£o dos nutrientes. Os efeitos do processamento em ingredientes, entretanto, ainda n√£o est√£o completamente elucidados. Assim, o trabalho objetivou avaliar algumas t√©cnicas de processamento no milho, quantitativamente o principal componente de uma ra√ß√£o para aves. Foram processadas tr√™s ra√ß√Ķes (tratamentos): T1 ‚Äď ra√ß√£o produzida com milho mo√≠do, sem processamento; T2 ‚Äď ra√ß√£o produzida com milho peletizado e T3: milho expandido e peletizado. As ra√ß√Ķes foram fornecidas na forma farelada, assim o milho do T2 e T3 foi triturado para a produ√ß√£o das ra√ß√Ķes. Para as vari√°veis de desempenho (consumo de ra√ß√£o, ganho de peso e convers√£o alimentar), foram alojados 600 frangos de corte da linhagem Cobb, criados de um a 42 dias de idade. Foi avaliado tamb√©m a digestibilidade da mat√©ria seca e energia digest√≠vel das ra√ß√Ķes. Foi utilizado delineamento inteiramente casualizado composto por 3 tratamentos e 8 repeti√ß√Ķes, com 25 aves por unidade experimental. O processamento do milho n√£o alterou o consumo de ra√ß√£o, ganho de peso m√©dio e convers√£o alimentar dos frangos nas fases inicial, crescimento e termina√ß√£o (P>0,05). As ra√ß√Ķes que utilizaram milho peletizado e milho expandido/peletizado apresentaram uma maior digestibilidade de mat√©ria seca e energia digest√≠vel (P 0.05) steps. The diets that used corn pellet andexpanded corn pellet had a higher digestibility of dry matter and digestible energy (P <0.05) compared to mash diet (unprocessed corn), without significant differences between them. We conclude that the benefits attributed to the processing of feed does not happen when these techniques are only used on corn

    Verteilung und Neuverteilung der Literaturausgaben in einem universit√§ren System : ein Weg, zwei Wege, viele Wege? ; √ľberarbeiteter Vortrag, gehalten auf dem 95. Deutschen Bibliothekartag in Dresden 2006

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    Das Bibliothekssystem der Universit√§t Frankfurt am Main ist seit dem Jahre 2005 in einer Phase des Umbruchs. Durch die √úberleitung der ehemaligen Stadt- und Universit√§tsbibliothek in die Tr√§gerschaft der Universit√§t mit gleichzeitiger vollst√§ndiger Integration der Senckenbergischen Bibliothek zu einer neuen Institution mit Namen "Universit√§tsbibliothek Johann Christian Senckenberg" vollzieht sich auf allen Ebenen ein struktureller Wandel. Da per gesetzlicher Vorgabe und von der Universit√§t erlassenen Bibliotheksordnung die funktionale Einschichtigkeit realisiert werden soll, werden nun auch die bisher autonomen dezentralen Bibliotheken sukzessive administrativ mit der UB zusammengef√ľhrt. Der Frage, wie dabei die zentralen und dezentralen Erwerbungsmittel zu einer sinnvollen Verteilung gef√ľhrt werden k√∂nnen, wird derzeit am Standort diskutiert. Der Beitrag versucht, schlaglichtartig den augenblicklichen Stand zu beleuchten

    Preval√™ncia de agravos periodontais e sua rela√ß√£o com fatores socioecon√īmicos na popula√ß√£o adulta de Florian√≥polis, SC.

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    TCC (gradua√ß√£o) - Universidade Federal de Santa Catarina. Centro de Ci√™ncias da Sa√ļde. Odontologia.A doen√ßa periodontal √© caracterizada por um processo inflamat√≥rio e infeccioso, que pode causar a perda de inser√ß√£o do ligamento periodontal e destrui√ß√£o do tecido √≥sseo circunjacente aos dentes. Dentre os potenciais fatores que podem ter influ√™ncia direta e indireta na ocorr√™ncia da doen√ßa periodontal, tem-se uso excessivo do tabaco e √°lcool, diabetes mellitus, obesidade e pior condi√ß√£o socioecon√īmica. O objetivo deste trabalho foi estimar a preval√™ncia de doen√ßa periodontal (presen√ßa de bolsa periodontal e perda de inser√ß√£o periodontal) e avaliar sua associa√ß√£o com vari√°veis socioecon√īmicas, especificamente escolaridade e renda. Os dados foram obtidos por meio de um estudo de coorte de base populacional, realizado nos anos de 2009 e 2012, com uma amostra representativa da popula√ß√£o adulta (20-59 anos) de Florian√≥polis, Santa Catarina. Os dados socioecon√īmicos e relativos √† condi√ß√£o periodontal foram obtidos com question√°rios e exames cl√≠nicos de condi√ß√Ķes bucais. Foram inclu√≠dos no estudo 1.112 indiv√≠duos, dos quais 2,5% [IC95%] 1,65-3,89 apresentaram doen√ßa periodontal (bolsa profunda e/ou perda de inser√ß√£o periodontal ‚Č• 4mm no mesmo dente ‚Äď DP2) e 3,7% [IC95%] 2,59-5,14 (bolsa profunda e/ou perda de inser√ß√£o periodontal ‚Č• 4mm n√£o necessariamente no mesmo dente ‚Äď DP3). Na an√°lise multivariada, a associa√ß√£o entre escolaridade do pai do entrevistado com DP3 (RC= 0,73; IC95% 0,33-1,63 para os participantes com pais apresentando de 9 a 12 anos de estudo e RC= 0,10; IC95% 0,00-1,07 para os com pais com 13 anos ou mais de estudo) foram estatisticamente significativas. Conclui-se que a preval√™ncia de doen√ßa periodontal no estudo foi baixa, podendo justificar-se pelas boas condi√ß√Ķes de vida da popula√ß√£o do munic√≠pio Por√©m, a rela√ß√£o existente entre pior posi√ß√£o socioecon√īmica e pior condi√ß√£o periodontal revela que, mesmo neste contexto, as desigualdades sociais relativas ao agravo s√£o preocupantes, tornando-se necess√°rio enfrent√°-las por meio de pol√≠ticas e servi√ßos sens√≠veis a esta quest√£o.Periodontal disease is characterized by inflammatory and infectious processes, which can cause periodontal ligament insertion loss and destruction of the surrounding bone tissue to the teeth. Among the potential factors that could have a direct and indirect influence on the occurrence of periodontal disease, there is excessive use of tobacco and alcohol, diabetes mellitus, obesity and lower socioeconomic status. The objective of this study was to estimate the prevalence of periodontal disease (presence of periodontal pockets and periodontal attachment loss) and evaluate its association with socioeconomic, specifically education and income variables. The informations were obtained from a study of population-based cohort, conducted in the years 2009 and 2012, with a representative sample of the adult population (20-59 years) in Florian√≥polis, Santa Catarina. Socioeconomic and related to periodontal status data were obtained from questionnaires and clinical examinations of oral conditions. 1,112 individuals were included in the study, of which 2.5% [CI95%] 1,65-3,89 had periodontal disease (pocket depth and / or periodontal attachment loss ‚Č• 4 mm) on the same tooth and 3.7% [CI95%] 2,59-5,14 in different teeth in the dental arch. In multivariate analysis, the association between father's educational level of the interviewee related with profound scholarship criteria and periodontal attachment loss ‚Č• 4 mm in different teeth arcade (OR = 0.73; [CI 95%] 0.33-1.63 for the father had 9-12 years of study and RP = 0.10; [CI 95%] 0.00-1.07 for the father who had 13 years or more of study) was statistically significant. We conclude that the prevalence of periodontal disease in the study was low, and can be justified by good living conditions of the local population, however, the relationship between lower socioeconomic status and poorer periodontal status reveals that, even in this context, social inequalities related to the offense are worrisome, making it necessary to address them through policies and services sensitive to this issue

    ROSAT HRI observations of Centaurus A

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    We present results from a sensitive high-resolution X-ray observation of the nearby active galaxy Centaurus A (NGC 5128) with the ROSAT HRI. The 65~ksec X-ray image clearly distinguishes different components of the X-ray emission from Cen A: the nucleus and the jet, the diffuse galaxy halo, and a number of individual sources associated with the galaxy. The luminosity of the nucleus increased by a factor of two compared to an earlier ROSAT observation in 1990. The high spatial resolution of the ROSAT HRI shows that most of the knots in the jet are extended both along and perpendicular to the jet axis. We report the detection of a new X-ray feature, at the opposite side of the X-ray jet which is probably due to compression of hot interstellar gas by the expanding southwestern inner radio lobe.Comment: To be published in Astrophys. Journal Letters. 4 pages, 3 plate

    Magnetic fields of our Galaxy on large and small scales

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    Magnetic fields have been observed on all scales in our Galaxy, from AU to kpc. With pulsar dispersion measures and rotation measures, we can directly measure the magnetic fields in a very large region of the Galactic disk. The results show that the large-scale magnetic fields are aligned with the spiral arms but reverse their directions many times from the inner-most arm (Norma) to the outer arm (Perseus). The Zeeman splitting measurements of masers in HII regions or star-formation regions not only show the structured fields inside clouds, but also have a clear pattern in the global Galactic distribution of all measured clouds which indicates the possible connection of the large-scale and small-scale magnetic fields.Comment: 9 pages. Invited Talk at IAU Symp.242, 'Astrophysical Masers and their Environments', Proceedings edited by J. M. Chapman & W. A. Baa
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