960 resultados para dark matter theory


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This article addresses factors that infl uence member commitment in sport clubs. Based on the theory of social action and the economic behaviour theory, it focuses not only on individual characteristics of club members but also on the corresponding structural conditions of sport clubs. Accordingly, a multilevel framework is developed for explaining member commitment in sport clubs. Different multilevel models were estimated in order to analyse the infl uences of both the individual and corresponding context Level in a sample of n = 1,699 members of 42 Swiss and German sport clubs. The multilevel analysis permitted an adequate handling of hierarchically structured data. Results of These multilevel analyses indicated that the commitment of members is not just an outcome of individual characteristics such as strong identifi cation with their club, positively perceived (collective) solidarity, satisfaction with their sport club, or voluntary engagement. It is also determined by club-specific structural conditions: commitment proves to be more probable in rural sport clubs and clubs that explicitly support sociability. Furthermore, cross-level effects in relation to member commitment were also found between the context variable sociability and the individual variable identification.

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This article introduces the emic–etic debate in the scientific study of religion\s and provides a frame for the special issue’s six articles on the topic. Departing from the broader debate’s early history in the 1960s, this article contextualizes the emic–etic debate and locates its point of entry into the scientific study of religion\s in the 1980s. This article argues that in the course of the debate the insider–outsider and emic–etic complexes have become entangled. In order to facilitate an understanding of the debate, this article maintains that the emic–etic debate in the scientific study of religion\s touches upon three central dimensions (existential–political, methodologi- cal, and epistemological). In order to move toward a clearer methodological and epis- temological framework, this article furthermore proposes an iterative model that locates insider–outsider at the level of observers and emic–etic at the level of categories.

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Samples taken at 10 cm intervals from DSDP Core 532B-17 contain variations in carbonate, opal, organic carbon, and terrigenous components that correlate with light-dark cycles in sediment color. The core site, at 1300 m water depth, is well above the CCD, yet the color variations appear to result largely from cyclical fluctuations in carbonate dissolution, which was greater during glacial periods. Higher concentrations of organic carbon and of terrigenous sediment components correlate with enhanced carbonate dissolution, but opal concentrations inversely correlate and suggest that biological productivity at this site diminished during glacial periods. A complicated glacial-interglacial picture emerges from the data. In interglacial times, upwelling associated with the Benguela Current produced abundant opaline material, organic matter was fairly well preserved, and carbonate was only moderately dissolved. In glacial times, the upwelling core shifted as sea level fell and winds intensified. Productivity in the waters over Site 532 decreased, but lateral supply of oxidizable organic matter enhanced carbonate dissolution, giving rise to light-dark cycles in these sediments.

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Ocean Drilling Program Legs 127 and 128 in the Japan Sea have revealed the existence of numerous dark-light rhythms of remarkable consistency in sediments of late Miocene, latest Pliocene, and especially Pleistocene age. Light-colored units within these rhythms are massive or bioturbated, consist of diatomaceous clays, silty clays, or nannofossil-rich clays, and are generally poor in organic matter. Dark-colored units are homogeneous, laminated, or thinly bedded and include substantial amounts of biogenic material such as well-preserved diatoms, planktonic foraminifers, calcareous nannofossils, and organic matter (maximum 7.4 wt%). The dark-light rhythms show a similar geometrical pattern on three different scales: First-order rhythms consist of a cluster dominated by dark-colored units followed by a cluster dominated by light-colored units (3-5 m). Spectral analysis of a gray-value time series suggests that the frequencies of the first-order rhythms in sediments of latest Pliocene and Pleistocene age correlate to the obliquity and the eccentricity cycles. The second-order dark-light rhythms include a light and a dark-colored unit (10-160 cm). They were formed in time spans of several hundred to several ten thousand years, with variance centering around 10,500 yr. This frequency may correspond to half the precessional cycle. Third-order rhythms appear as laminated or thinly bedded dark-light couplets (2-15 mm) within the dark-colored units of the second-order rhythms and may represent annual frequencies. In interpreting the rhythms, we have to take into account that (1) the occurrence of the first- and second-order rhythms is not necessarily restricted to glacial or interglacial periods as is shown by preliminary stable-isotope analysis and comparison with the published d18O record; (2) they appear to be Milankovitch-controlled; and (3) a significant number of the rhythms are sharply bounded. The origin of the dark-light rhythms is probably related to variations in monsoonal activity in the Japan Sea, which show annual frequencies, but also operates in phase with the orbital cycles.

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Rock magnetic/paleoclimatic/diagenetic relationships of sediments spanning the last 0.78 Ma have been investigated using samples collected from light and dark layers recovered at ODP Sites 794 (Yamato Basin) and 795 (Japan Basin). Rock-magnetic parameters (K, Kfd, ARM, SIRM, S-ratio) are shown to reflect diagenetic processes and climate-related variations in the concentration, mineralogy and grain-size of the magnetic minerals contained within the sediments. The magnetic mineralogy is dominated by ferrimagnetic (magnetite-type) minerals with a small contribution made by hematite and iron sulphides such as pyrrhotite and/or greigite. Magnetic mineral concentration and grain size vary between light and dark layers with the former characterized by a higher magnetic content and a finer magnetic grain size. Magnetite dissolution, related to sulfate reduction due to bacterial degradation of organic matter, is the process responsible for the magnetic characteristics observed in the dark layers, testifying to the reducing conditions in the basin. Variations in the rock magnetic properties of the sediments are strongly correlated with global oxygen isotope fluctuations, with glacial stages characterized by a lower magnetic mineral content and a coarser magnetic grain size relative to interglacial stages. Major downcore changes in the magnetic properties observed at Site 794 can be related to changes in the oceanographic conditions of the basin associated with the flow of the warm Tsushima Current into the Japan Sea at about 0.35-0.40 Ma ago.

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The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. The present data set provides continuous measurements made with a WETLabs Eco-FL sensor mounted on the flowthrough system between June 4th, 2011 and March 30th, 2012. Data was recorded approximately every 10s. Two issues affected the data: 1. Periods when the water 0.2µm filtered water were used as blanks and 2. Periods where fluorescence was affected by non-photochemical quenching (NPQ, chlorophyll fluorescence is reduced when cells are exposed to light, e.g. Falkowski and Raven, 1997). Median data and their standard deviation were binned to 5min bins with period of light/dark indicated by an added variable (so that NPQ affected data could be neglected if the user so chooses). Data was first calibrated using HPLC data collected on the Tara (there were 36 data within 30min of each other). Fewer were available when there was no evident NPQ and the resulting scale factor was 0.0106 mg Chl m-3/count. To increase the calibration match-ups we used the AC-S data which provided a robust estimate of Chlorophyll (e.g. Boss et al., 2013). Scale factor computed over a much larger range of values than HPLC was 0.0088 mg Chl m-3/count (compared to 0.0079 mg Chl m-3/count based on manufacturer). In the archived data the fluorometer data is merged with the TSG, raw data is provided as well as manufacturer calibration constants, blank computed from filtered measurements and chlorophyll calibrated using the AC-S. For a full description of the processing of the Eco-FL please see Taillandier, 2015.

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In this work, we show how number theoretical problems can be fruitfully approached with the tools of statistical physics. We focus on g-Sidon sets, which describe sequences of integers whose pairwise sums are different, and propose a random decision problem which addresses the probability of a random set of k integers to be g-Sidon. First, we provide numerical evidence showing that there is a crossover between satisfiable and unsatisfiable phases which converts to an abrupt phase transition in a properly defined thermodynamic limit. Initially assuming independence, we then develop a mean-field theory for the g-Sidon decision problem. We further improve the mean-field theory, which is only qualitatively correct, by incorporating deviations from independence, yielding results in good quantitative agreement with the numerics for both finite systems and in the thermodynamic limit. Connections between the generalized birthday problem in probability theory, the number theory of Sidon sets and the properties of q-Potts models in condensed matter physics are briefly discussed

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Although progressive functional brain network disruption has been one of the hallmarks of Alzheimer?s Dis- ease, little is known about the origin of this functional impairment that underlies cognitive symptoms. We in- vestigated how the loss of white matter (WM) integrity disrupts the organization of the functional networks at different frequency bands. The analyses were performed in a sample of healthy elders and mild cognitive im- pairment (MCI) subjects. Spontaneous brain magnetic activity (measured with magnetoencephalography) was characterized with phase synchronization analysis, and graph theory was applied to the functional networks. We identified WM areas (using diffusion weighted magnetic resonance imaging) that showed a statistical de- pendence between the fractional anisotropy and the graph metrics. These regions are part of an episodic mem- ory network and were also related to cognitive functions. Our data support the hypothesis that disruption of the anatomical networks influences the organization at the functional level resulting in the prodromal dementia syndrome of MCI.