A Link Between the Semi-Major Axis of Extrasolar Gas Giant Planets and Stellar Metallicity

The fact that most extrasolar planets found to date are orbiting metal-rich stars lends credence to the core accretion mechanism of gas giant planet formation over its competitor, the disc instability mechanism. However, the core accretion mechanism is not refined to the point of explaining orbital parameters such as their unexpected semi-major axes and eccentricities. We propose a model, which correlates the metallicity of the host star with the original semi-major axis of its most massive planet, prior to migration, considering that the core accretion scenario governs giant gas planet formation. The model predicts that the optimum regions for planetary formation shift inward as stellar metallicity decreases, providing an explanation for the observed absence of long period planets in metal-poor stars. We compare our predictions with the available data on extrasolar planets for stars with masses similar to the mass of the Sun. A fitting procedure produces an estimate of what we define as the Zero Age Planetary Orbit (ZAPO) curve as a function of the metallicity of the star. The model also hints that the lack of planets circling metal-poor stars may be partly caused by an enhanced destruction probability during the migration process, since the planets lie initially closer to the central stars.Comment: Nature of the replacement: According to recent simulations, the temperature profile, T, is more adequately reproduced by beta = 1 rather than beta = 2. We have introduced a distance scale factor that solves the very fast drop of T for low metallicity and introduces naturally the inferior distance limit of our ZAPO. Under this modification all the fitting process was altere

Antocianinas em uvas de variedades viníferas.

Estudou-se, neste trabalho, na vindima de 1979, a ocorrência das antocianinas em variedades de uvas tintas, Bonarda, Merlot, Barbera O'ASTI, Gamay-Beaujolais, Cabernet Franc, Pinot Noir e Canaiolo, cultivadas na região vitivin ícola de Bento Gonçalves, RS. A separação das antocianinas foi estudada por cromatografia em camada delgada unidimensional, e as concentrações, expressas em malvidina-3 monoglicosídeo (rng/l). As variedades estudadas somente apresentaram antocianinas-3-monoglicosídeos, comprovando, portanto, pertencerem à espécie Vitis vinifera. Essa identificação é de grande valia para a detecção de fraudes em vinhos finos tintos. A variedade "Pinot Noir" apresentou maior concentração, 764,12 mg/l; e a Canaiolo, 501,49 mg/l, a de menor concentração. Houve, contudo, uma variação entre as variedades estudadas, o que indica a possibilidade de seleção de variedades pela intensidade de cor, para a elaboração de vinhos tintos

Network analyses of internet gaming disorder symptoms and their links with different types of motivation

The study used regularized partial correlation network analysis (EBICglasso) to examine the structure of DSM-5 internet gaming disorder (IGD) symptoms (network 1); and the associations of the IGD symptoms in the network with different types of motivation as defined in the self-determination theory i.e., intrinsic motivation (engaging in an activity for something unrelated to the activity), identified regulation (engaging in the activity because it aligns with one’s values and/or goals), external regulation (engagement in activity being driven by external rewards and/or approval), and amotivation (engaging in an activity without often understanding why) (network 2). Participants were 968 adults from the general community. They completed self-rating questionnaires covering IGD symptoms and different types of motivation. The findings for network 1 showed mostly positive connections between the symptoms within the IGD network. The most central symptom was loss of control, followed by continuation, withdrawal symptoms, and tolerance. In general, these symptoms were more strongly connected with each other than with the rest of the IGD symptoms. The findings for network 2 showed that the different types of motivation were connected differently with the different IGD symptoms. For instance, the likeliest motivation for the preoccupation and escape symptoms is intrinsic motivation, and for negative consequences, it is low identified regulation. Overall, the findings showed a novel understanding of the structure of the IGD symptoms, and the motivations underlying them. The clinical implications of the findings for assessment and treatment of IGD are discussed

Uso e cobertura das terras na área de entorno do reservatório da Usina Hidrelétrica de Tombos (MG).

O trabalho mapeia o uso e cobertura vegetal das terras na área de entorno do reservatório da UHE de Tombos. A metodologia utilizada combinou práticas de geoprocessamento, produtos de sensoriamento remoto, sistema de informação geográfica (SIG) e trabalhos de campo. Os resultados mostram que a maior parte da área encontra-se recoberta com pastagens, sendo 41,11% com pasto limpo e 15,10% com pasto sujo, seguidos de matas com 15,29% da área, os demais 28,4% corresponde às outras classes de uso

Increased levels of Stress-inducible phosphoprotein-1 accelerates amyloid-β deposition in a mouse model of Alzheimer’s disease

Molecular chaperones and co-chaperones, which are part of the protein quality control machinery, have been shown to regulate distinct aspects of Alzheimer’s Disease (AD) pathology in multiple ways. Notably, the co-chaperone STI1, which presents increased levels in AD, can protect mammalian neurons from amyloid-β toxicity in vitro and reduced STI1 levels worsen Aβ toxicity in C. elegans. However, whether increased STI1 levels can protect neurons in vivo remains unknown. We determined that overexpression of STI1 and/or Hsp90 protected C. elegans expressing Aβ(3–42) against Aβ-mediated paralysis. Mammalian neurons were also protected by elevated levels of endogenous STI1 in vitro, and this effect was mainly due to extracellular STI1. Surprisingly, in the 5xFAD mouse model of AD, by overexpressing STI1, we find increased amyloid burden, which amplifies neurotoxicity and worsens spatial memory deficits in these mutants. Increased levels of STI1 disturbed the expression of Aβ-regulating enzymes (BACE1 and MMP-2), suggesting potential mechanisms by which amyloid burden is increased in mice. Notably, we observed that STI1 accumulates in dense-core AD plaques in both 5xFAD mice and human brain tissue. Our findings suggest that elevated levels of STI1 contribute to Aβ accumulation, and that STI1 is deposited in AD plaques in mice and humans. We conclude that despite the protective effects of STI1 in C. elegans and in mammalian cultured neurons, in vivo, the predominant effect of elevated STI1 is deleterious in AD

Orbital Magnetism in Ensembles of Parabolic Potentials

We study the magnetic susceptibility of an ensemble of non-interacting electrons confined by parabolic potentials and subjected to a perpendicular magnetic field at finite temperatures. We show that the behavior of the average susceptibility is qualitatively different from that of billiards. When averaged over the Fermi energy the susceptibility exhibits a large paramagnetic response only at certain special field values, corresponding to comensurate classical frequencies, being negligible elsewhere. We derive approximate analytical formulae for the susceptibility and compare the results with numerical calculations.Comment: 4 pages, 4 figures, REVTE

Stochastic stabilization of cosmological photons

The stability of photon trajectories in models of the Universe that have constant spatial curvature is determined by the sign of the curvature: they are exponentially unstable if the curvature is negative and stable if it is positive or zero. We demonstrate that random fluctuations in the curvature provide an additional stabilizing mechanism. This mechanism is analogous to the one responsible for stabilizing the stochastic Kapitsa pendulum. When the mean curvature is negative it is capable of stabilizing the photon trajectories; when the mean curvature is zero or positive it determines the characteristic frequency with which neighbouring trajectories oscillate about each other. In constant negative curvature models of the Universe that have compact topology, exponential instability implies chaos (e.g. mixing) in the photon dynamics. We discuss some consequences of stochastic stabilization in this context.Comment: 4 pages, 3 postscript figures in color which are also appropriate for black and white printers; v2 emphasizes relevance to flat as well as negatively curved cosmologies; to appear in J. Phys.

A DESORIENTAÇÃO GERAL

Este ensaio se interroga sobre a situação de impasse geral na qual vivemos no momento presente, devido à crise profunda da política ocidental moderna e, portanto, da condição histórica ela mesma, enquanto promessa de emancipação dos sujeitos. A falta geral de horizonte, o desaparecimento de um verdadeiro projeto crítico, histórico-político, o vazio de sentido que uma política reduzida à gestão do sistema liberal deixa na sua ruína, caracterizam esse impasse. A questão atual é portanto a da desorientação geral. Esta define o motivo condutor o mais apto a reunir e a articular os diferentes fios dos eventos que tramam hoje o nosso destino. Estes fios trazem todos a marca da ameaça. Que seja a expansão e a intensificação dos atentados do salafismo djihadista na França, na Europa, nos EUA, e a dita “co-radicalização” correspondente da extrema direita islamofóbica; ou o crescimento atual das novas extremas direitas populistas; ou ainda a “política das coisas” do próprio sistema ocidental, reduzindo a política em administração e elegendo a segurança como técnica de governo. Estas ameaças não são todas da mesma espécie, evidentemente, nem se equivalem. No entanto todas têm em comum o fato de atacar em última análise, para lá das solidariedades coletivas, a vida subjetiva, singular, o si. Ou seja, mais precisamente, a relação de si consigo mesmo e com o outro de si, por meio da qual somente um sujeito pode manter uma “linha geral” ao longo de sua existência. De forma que, sob as ameaças diversas, o sujeito perde e se perde (se desorienta) em todas as frentes de luta. Desprovido de sua relação a si, o sujeito ameaçado tende a ser minado : conduzido, dirigido, gerido. última bússola do sobrevivente na época que corre : os recursos do labor que consiste a reatar uma relação de si consigo mesmo e com o outro de si, condição e princípio de toda orientação possível. última forma capaz de opor uma resistência ao tempo presente. Elaborar esses recursos, perlaborá-los, tal é, hoje como ontem, a tarefa da arte, da literatura, do pensamento.   PALAVRAS-CHAVE: Arte; outro (de si); destino; djihadista; emancipação; existência; extrema direita.     RESUME  L'essai s’interroge sur la situation de grave impasse générale dans laquelle le monde se trouve aujourd'hui. Cette impasse est présentée comme engendrée par la crise profonde de la politique occidentale moderne, et partant de sa perspective historique, comprise comme promesse d'émancipation des sujets. Le manque général d'horizon historico-politique, la disparition d'un véritable projet critique, le vide de sens qu'une politique réduite à la gestion du système libéral engendre dans sa ruine, caractérisent cette impasse. La question actuelle est donc bien celle de la désorientation générale. Cela définit le motif conducteur le plus apte à rassembler et à articuler les différents fils des événements qui tracent notre destin aujourd'hui. Ces fils portent tous la marque de la menace : que ce soit l'expansion et l'intensification des attaques du salafisme djihadiste en France, en Europe ou aux États-Unis, et ladite « co-radicalisation » de l’extrême droite islamophobe ; ou la croissance actuelle de nouvelles extrêmes droites populistes ; ou la « politique des choses » (la nouvelle technocratie) du système occidental lui-même, réduisant la politique à la gestion des affaires du système et choisissant « la sécurité » comme technique de gouvernement. Ces menaces ne sont pas toutes de même nature, bien sûr, et ne s’équivalent pas. Cependant, elles ont toutes en commun le fait d'attaquer en dernière analyse, au-delà des solidarités collectives, la vie subjective, singulière : le soi. C'est-à-dire, plus précisément : la relation de soi à soi-même et à l'autre de soi, suivant laquelle seulement un sujet peut s’esquisser [se dessiner lui-même] et maintenir une « ligne générale » au long de son existence. De sorte que, sous ces différentes menaces, le sujet perd et se perd (se désoriente) sur tous les fronts de la lutte, sur tous les tableaux. Dépouillé de sa relation à lui-même, le sujet menacé tend à être complètement miné : mené, dirigé, géré tout au long de son existence. Il s’ensuit la dernière boussole du survivant, dans l'époque qui court : celle que fournissent les ressources du travail qui consiste à reprendre une relation de soi avec soi-même et avec l'autre de soi, condition et principe de toute orientation possible. Ultime forme capable d'opposer une résistance au temps présent. Or, élaborer ces ressources, les perlaborer, c'est précisément la tâche de l'art, de la littérature, de la pensée.   MOTS-CLÉS: art; autre (de soi); destin; djihadiste; émancipation; existence; extrême droite.     ABSTRACT The essay questions the situation of serious global impasse in which the world is today. This impasse is portrayed as engendered by the deep crisis of modern Western politics, and of its historical perspective, understood as a promise of emancipation of subjects. The general lack of a historical-political horizon, the disappearance of a true critical project, the meaningless that a policy reduced to the management of the liberal system engenders in its ruin, characterize this impasse. The question today is therefore that of a general disorientation. This defines the leitmotiv for gathering and articulating the different threads of events that map out our destiny today. These threads all bear the mark of the threat: that it is the expansion and the intensification of attacks of the Jihadist salafist in France, Europe or the United States, and the "co-radicalization" of the Islamophobic far right; or the current growth of new populists far right; or the "politics of things" (the new technocracy) of the Western system itself, reducing politics to the management of the system's affairs and choosing "security" as a technique of government. These threats are not all of the same nature, of course, and they are not equivalent. However, they all have in common the fact of attacking, in the last analysis, beyond collective solidarities, the subjective, singular life: the self. That is to say, more precisely: the relation of oneself to oneself and to the other of oneself, according to which only a subject can to draw oneself and maintain a "general line" throughout his life. So, under these different threats, the subject loses and loses (disorients) oneself on all fronts of the struggle. Stripped of its relation to itself, the threatened subject tends to be completely undermined: led, directed, managed throughout its existence. It follows the last compass of the survivor, in the time that is running: that provided by the resources of work which consists in taking up a relationship of oneself with oneself and with the other of oneself, a condition and principle of any possible orientation. Ultimate form able to oppose a resistance to the present time. Now, to elaborate these resources, to working-through them, is precisely the task of art, of literature, of thought.   KEYWORDS: art; other (of oneself); destiny; jihadist; emancipation; existence ; far right

Jeux de langage et théorie de la communication : notes sur Wittgenstein et Habermas

La théorie wittgensteinienne des jeux de langage fait l'objet d'une réception ambiguë dans la théorie communicationnelle de Habermas. La diversité irréductible des jeux de langage s'y voit unifiée sous une téléologie générale de la communication, alors que pour Wittgenstein rien à l'intérieur du langage ne permet de conclure à une « nature » du langage en général, ou à une fonction privilégiée de celui-ci