887 resultados para Specific theories and interaction models


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This congress proceedings volume includes all abstracts submitted to the 14th European Congress of Sport Psychology of the European Federation of Sport Psychology FEPSAC that have been accepted by the scientific evaluation committee. Content: six keynote lectures, Panteleimon ("Paddy") Ekkekakis: Escape from Cognitivism: Exercise as Hedonic Experience; Sergio Lara-Bercial and Cliff Mallett: Serial Winning Coaches – Vision, People and Environment; Kari Fasting: Sexual Harassment and Abuse in Sport – Implications for Sport Psychologists; Claudia Voelcker-Rehage: Benefits of Physical Activity and Fitness for Lifelong Motor and Cognitive Development – Brain and Behaviour; Nancy J. Cooke: Interactive Team Cognition: Focusing on Team Dynamics; Chris Harwood: Doing Sport Psychology? Critical Reflections as a Scientist-Practitioner. Abstracts of 11 invited symposia, 65 submitted symposia, 8 special sessions, and 5 poster sessions.

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67P/Churyumov-Gerasimenko (67P) is a Jupiter-family comet and the object of investigation of the European Space Agency mission Rosetta. This report presents the first full 3D simulation results of 67P’s neutral gas coma. In this study we include results from a direct simulation Monte Carlo method, a hydrodynamic code, and a purely geometric calculation which computes the total illuminated surface area on the nucleus. All models include the triangulated 3D shape model of 67P as well as realistic illumination and shadowing conditions. The basic concept is the assumption that these illumination conditions on the nucleus are the main driver for the gas activity of the comet. As a consequence, the total production rate of 67P varies as a function of solar insolation. The best agreement between the model and the data is achieved when gas fluxes on the night side are in the range of 7% to 10% of the maximum flux, accounting for contributions from the most volatile components. To validate the output of our numerical simulations we compare the results of all three models to in situ gas number density measurements from the ROSINA COPS instrument. We are able to reproduce the overall features of these local neutral number density measurements of ROSINA COPS for the time period between early August 2014 and January 1 2015 with all three models. Some details in the measurements are not reproduced and warrant further investigation and refinement of the models. However, the overall assumption that illumination conditions on the nucleus are at least an important driver of the gas activity is validated by the models. According to our simulation results we find the total production rate of 67P to be constant between August and November 2014 with a value of about 1 × 10²⁶ molecules s⁻¹.

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The reference librarian's task is to translate the patron's question into one that can be answered with the library's resources. The first element of that task is to know what the patron wants; the second is to know what resources the library has and how to use them. Reference librarians must learn continuously throughout their careers, both because new resources become available, but also because patrons present questions requiring new resources. This article will focus on how to determine what kind of information the patron needs through the reference interview.

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Dua and Miller (1996) created leading and coincident employment indexes for the state of Connecticut, following Moore's (1981) work at the national level. The performance of the Dua-Miller indexes following the recession of the early 1990s fell short of expectations. This paper performs two tasks. First, it describes the process of revising the Connecticut Coincident and Leading Employment Indexes. Second, it analyzes the statistical properties and performance of the new indexes by comparing the lead profiles of the new and old indexes as well as their out-of-sample forecasting performance, using the Bayesian Vector Autoregressive (BVAR) method. The new indexes show improved performance in dating employment cycle chronologies. The lead profile test demonstrates that superiority in a rigorous, non-parametric statistic fashion. The mixed evidence on the BVAR forecasting experiments illustrates the truth in the Granger and Newbold (1986) caution that leading indexes properly predict cycle turning points and do not necessarily provide accurate forecasts except at turning points, a view that our results support.

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This paper revisits the issue of conditional volatility in real GDP growth rates for Canada, Japan, the United Kingdom, and the United States. Previous studies find high persistence in the volatility. This paper shows that this finding largely reflects a nonstationary variance. Output growth in the four countries became noticeably less volatile over the past few decades. In this paper, we employ the modified ICSS algorithm to detect structural change in the unconditional variance of output growth. One structural break exists in each of the four countries. We then use generalized autoregressive conditional heteroskedasticity (GARCH) specifications modeling output growth and its volatility with and without the break in volatility. The evidence shows that the time-varying variance falls sharply in Canada, Japan, and the U.K. and disappears in the U.S., excess kurtosis vanishes in Canada, Japan, and the U.S. and drops substantially in the U.K., once we incorporate the break in the variance equation of output for the four countries. That is, the integrated GARCH (IGARCH) effect proves spurious and the GARCH model demonstrates misspecification, if researchers neglect a nonstationary unconditional variance.

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Life expectancy has consistently increased over the last 150 years due to improvements in nutrition, medicine, and public health. Several studies found that in many developed countries, life expectancy continued to rise following a nearly linear trend, which was contrary to a common belief that the rate of improvement in life expectancy would decelerate and was fit with an S-shaped curve. Using samples of countries that exhibited a wide range of economic development levels, we explored the change in life expectancy over time by employing both nonlinear and linear models. We then observed if there were any significant differences in estimates between linear models, assuming an auto-correlated error structure. When data did not have a sigmoidal shape, nonlinear growth models sometimes failed to provide meaningful parameter estimates. The existence of an inflection point and asymptotes in the growth models made them inflexible with life expectancy data. In linear models, there was no significant difference in the life expectancy growth rate and future estimates between ordinary least squares (OLS) and generalized least squares (GLS). However, the generalized least squares model was more robust because the data involved time-series variables and residuals were positively correlated. ^

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A stratigraphy-based chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core has been derived by transferring the annual layer counted Greenland Ice Core Chronology 2005 (GICC05) and its model extension (GICC05modelext) from the NGRIP core to the NEEM core using 787 match points of mainly volcanic origin identified in the electrical conductivity measurement (ECM) and dielectrical profiling (DEP) records. Tephra horizons found in both the NEEM and NGRIP ice cores are used to test the matching based on ECM and DEP and provide five additional horizons used for the timescale transfer. A thinning function reflecting the accumulated strain along the core has been determined using a Dansgaard-Johnsen flow model and an isotope-dependent accumulation rate parameterization. Flow parameters are determined from Monte Carlo analysis constrained by the observed depth-age horizons. In order to construct a chronology for the gas phase, the ice age-gas age difference (Delta age) has been reconstructed using a coupled firn densification-heat diffusion model. Temperature and accumulation inputs to the Delta age model, initially derived from the water isotope proxies, have been adjusted to optimize the fit to timing constraints from d15N of nitrogen and high-resolution methane data during the abrupt onset of Greenland interstadials. The ice and gas chronologies and the corresponding thinning function represent the first chronology for the NEEM core, named GICC05modelext-NEEM-1. Based on both the flow and firn modelling results, the accumulation history for the NEEM site has been reconstructed. Together, the timescale and accumulation reconstruction provide the necessary basis for further analysis of the records from NEEM.

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Many genera of modern planktic foraminifera are adapted to nutrient-poor (oligotrophic) surface waters by hosting photosynthetic symbionts, but it is unknown how they will respond to future changes in ocean temperature and acidity. Here we show that ca. 40 Ma, some fossil photosymbiont-bearing planktic foraminifera were temporarily 'bleached' of their symbionts coincident with transient global warming during the Middle Eocene Climatic Optimum (MECO). At Ocean Drilling Program (ODP) Sites 748 and 1051 (Southern Ocean and mid-latitude North Atlantic, respectively), the typically positive relationship between the size of photosymbiont-bearing planktic foraminifer tests and their carbon isotope ratios (d13C) was temporarily reduced for ~100 k.y. during the peak of the MECO. At the same time, the typically photosymbiont-bearing planktic foraminifera Acarinina suffered transient reductions in test size and relative abundance, indicating ecological stress. The coincidence of minimum d18O values and reduction in test size-d13C gradients suggests a link between increased sea-surface temperatures and bleaching during the MECO, although changes in pH and nutrient availability may also have played a role. Our findings show that host-photosymbiont interactions are not constant through geological time, with implications for both the evolution of trophic strategies in marine plankton and the reliability of geochemical proxy records generated from symbiont-bearing planktic foraminifera.

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The source rock potential of Cretaceous organic rich whole rock samples from deep sea drilling project (DSDP) wells offshore southwestern Africa was investigated using bulk and quantitative pyrolysis techniques. The sample material was taken from organic rich intervals of Aptian, Albian and Turonian aged core samples from DSDP site 364 offshore Angola, DSDP well 530A north of the Walvis Ridge offshore Namibia, and DSDP well 361 offshore South Africa. The analytical program included TOC, Rock-Eval, pyrolysis GC, bulk kinetics and micro-scale sealed vessel pyrolysis (MSSV) experiments. The results were used to determine differences in the source rock petroleum type organofacies, petroleum composition, gas/oil ratio (GOR) and pressure-volume-temperature (PVT) behavior of hydrocarbons generated from these black shales for petroleum system modeling purposes. The investigated Aptian and Albian organic rich shales proved to contain excellent quality marine kerogens. The highest source rock potential was identified in sapropelic shales in DSDP well 364, containing very homogeneous Type II and organic sulfur rich Type IIS kerogen. They generate P-N-A low wax oils and low GOR sulfur rich oils, whereas Type III kerogen rich silty sandstones of DSDP well 361 show a potential for gas/condensate generation. Bulk kinetic experiments on these samples indicate that the organic sulfur contents influence kerogen transformation rates, Type IIS kerogen being the least stable. South of the Walvis Ridge, the Turonian contains predominantly a Type III kerogen. North of the Walvis Ridge, the Turonian black shales contain Type II kerogen and have the potential to generate P-N-A low and high wax oils, the latter with a high GOR at high maturity. Our results provide the first compositional kinetic description of Cretaceous organic rich black shales, and demonstrate the excellent source rock potential, especially of the Aptian-aged source rock, that has been recognized in a number of the South Atlantic offshore basins.

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This paper explains how the Armington-Krugman-Melitz supermodel developed by Dixon and Rimmer can be parameterized, and demonstrates that only two kinds of additional information are required in order to extend a standard trade model to include Melitz-type monopolistic competition and heterogeneous firms. Further, it is shown how specifying too much additional information leads to violations of the model constraints, necessitating adjustment and reconciliation of the data. Once a Melitz-type model is parameterized, a Krugman-type model can also be parameterized using the calibrated values in the Melitz-type model without any additional data. Sample code for the General Algebraic Modeling System (GAMS) has also been prepared to promote the innovative supermodel in the AGE community.

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This paper explores the consequences of the emerging rivalry between Japanese and Chinese manufacturers. It focuses specifically on industrial organisation, one of the key factors that underlie the competitiveness of manufacturing industries. The question to be asked is what happens when distinctive models of industrial organisation, coming from Japan and China, clash in a developing country. An in-depth longitudinal analysis of the Vietnamese motorcycle industry adopting a modified version of the global value chain governance theory shows that a decade-long industrial transformation resulted in organisational diversity. The implications of the analysis for the literature on industrial organisation are discussed.