3,747 research outputs found
Regional convergence in the European Union (1985-1999). A spatial dynamic panel analysis
We estimate the speed of income convergence for a sample of 196 European NUTS 2 regions over the period 1985-1999. So far there is no direct estimator available for dynamic panels with strong spatial dependencies. We propose a two-step procedure, which involves first spatial filtering of the variables to remove the spatial correlation, and application of standard GMM estimators for dynamic panels in a second step. Our results show that ignorance of the spatial correlation leads to potentially misleading results. Applying a system GMM estimator on the filtered variables, we obtain a speed of convergence of seven per cent.
The Foraging Ecology of South American Sea Lions (Otaria flavescens) on the Patagonian Shelf
The aim of this study was to elucidate the foraging ecology of South American sea lions (Otaria flavescens) on the Patagonian shelf. Data from satellite tags revealed that male sea lions use a much larger part of the shelf than females and often reach areas close to the shelf break, which may be related to the highly productive shelf break front. The data also showed a high site fidelity, both towards feeding grounds and haul-out sites. Calculations of food consumption revealed that the impact that males have on their prey resources depends on the time that the animals spend at sea, and thus the distance to suitable foraging grounds. A new non-electronic release-mechanism was developed for the recovery of dead reckoners that were used to study the diving behaviour of sea lions. The diving data supported the expectations that males, because of their larger size, had a greater diving capacity than females, which lead to a greater dive efficiency at depths greater than 45m. The use of an Area-Interest-Index to determine space usage revealed that sea lion foraging trips can be divided into distinctive travel and foraging phases. Differences in this index were also visible on the scale of individual dives
The IAB establishment panel : from sample to survey to projection
"The IAB Establishment Panel is an annual survey of establishments and is unique in Germany, as it represents all industries and establishment sizes nationwide and can also be analysed on a longitudinal basis. The design of the IAB Establishment Panel was developed in the early 1990s and subjected to a wide range of tests. This process also involved parallel development activities taking place on the Hannover Firm Panel, which were carried out on behalf of the "Forschungsstelle Firmenpanel" at the University of Hanover (Gerlach et al.: 1998) and the Institute for Applied Economic Research in Tübingen (IAW). The survey began in West Germany in 1993, with the aim of building up a representative information system for continuous analysis of labour demand. It has been carried out in East Germany since 1996, making it a nationwide survey. The IAB Establishment Panel is conceived as a longitudinal survey, i.e. a large majority of the same establishments are interviewed every year. Consequently, it enables both analysis of developments across time through comparison of cross-sectional data on different points in time, and also longitudinal studies of individual establishments. Now in the IAB Establishment Panel approx. 16,000 establishments are surveyed on a large number of employment policy-related subjects, including employment development, business policy and business development, investment activities, innovations in the establishment, public funding, personnel structure, vocational training and apprenticeships, new and exiting personnel, recruitment, wages and salaries, working times in the establishment, further training and general data on the establishment. The survey also includes varying focal topics every year. With the exception of Hamburg, all the German federal states (Bundesländer) currently contribute regional extension samples to the IAB Establishment Panel. This firstly enables evaluations on the federal state level, and secondly results in a total range of samples that significantly widens the evaluation options on the nationwide level. The IAB Establishment Panel contains high data quality, achieved by means of the high-quality sample, the high exploitation level and the sophisticated process of data monitoring and error correction. The survey is carried out by TNS Infratest Sozialforschung GmbH on behalf of the IAB. A general introduction to the IAB Establishment Panel is contained in German in Bellmann (2002) or in English in Kölling (2000). The IAB Establishment Panel is based on a complex study design, which also presents challenges for users of the dataset. This paper provides an overview of the methodology of the IAB Establishment Panel. It goes into detail on the design of the samples and survey, the weighting process, and data access at the Research Data Centre (FDZ) of the Federal Employment Agency (BA) at the Institute for Employment Research (IAB). The most important points are presented at the beginning of each chapter. It is intended for users of the IAB Establishment Panel, firstly as a collection of methodological aspects of the IAB Establishment Panel, and secondly to make it easier for first-time users in particular to start using the data. This paper is also aimed at users of the IAB Linked-Employer-Employee Dataset (LIAB1), in which the IAB Establishment Panel is an important component." (Author's abstract, IAB-Doku) ((en)) Additional Information Here you can find the German version of the report.IAB-Betriebspanel, Datengewinnung, Stichprobenverfahren, Stichprobe, Erhebungsmethode, Befragung, Fragebogen, Antwortverhalten, Datenaufbereitung, Datenanalyse, Hochrechnung, Querschnittuntersuchung, Längsschnittuntersuchung
NUEVAS TECNOLOGÍAS EN LOS PROCESOS DE FORMACIÓN IMBRICADAS CON EL CAMPO LABORAL”
Investigar los recursos tecnológicos educativos utilizados en el proceso de enseñanza – aprendizaje del profesor en disciplinas industriales y del técnico superior para su formación, desde la mirada didáctica y desde su posterior utilización en el campo laboral
How do local habitat management and landscape structure at different spatial scales affect fritillary butterfly distribution on fragmented wetlands?
Habitat fragmentation, patch quality and landscape structure are important predictors for species richness. However, conservation strategies targeting single species mainly focus on habitat patches and neglect possible effects of the surrounding landscape. This project assesses the impact of management, habitat fragmentation and landscape structure at different spatial scales on the distribution of three endangered butterfly species, Boloria selene, Boloria titania and Brenthis ino. We selected 36 study sites in the Swiss Alps differing in (1) the proportion of suitable habitat (i.e., wetlands); (2) the proportion of potential dispersal barriers (forest) in the surrounding landscape; (3) altitude; (4) habitat area and (5) management (mowing versus grazing). Three surveys per study site were conducted during the adult flight period to estimate occurrence and density of each species. For the best disperser B. selene the probability of occurrence was positively related to increasing proportion of wetland on a large spatial scale (radius: 4,000m), for the medium disperser B. ino on an intermediate spatial scale (2,000m) and for the poorest disperser B. titania on a small spatial scale (1,000m). Nearby forest did not negatively affect butterfly species distribution but instead enhanced the probability of occurrence and the population density of B. titania. The fen-specialist B. selene had a higher probability of occurrence and higher population densities on grazed compared to mown fens. The altitude of the habitat patches affected the occurrence of the three species and increasing habitat area enhanced the probability of occurrence of B. selene and B. ino. We conclude that, the surrounding landscape is of relevance for species distribution, but management and habitat fragmentation are often more important. We suggest that butterfly conservation should not focus only on a patch scale, but also on a landscape scale, taking into account species-specific dispersal abilitie
ISIS, die neue Informationsplattform der Saarländischen Universitäts- und Landesbibliothek : ein Praxisbericht
Emerging population of gap-opening planets around type-A stars -- Long-term evolution of the forming planets around HD 163296
The presence of forming planets embedded in their protoplanetary disks has
been inferred from the detection of multiring structures in such disks. Most of
these suspected planets are undetectable by direct imaging observations at
current measurement sensitivities. Inward migration and accretion might make
these putative planets accessible to the Doppler method, but the actual extent
of growth and orbital evolution remains unconstrained.
Under the premise that the gaps in the disk around HD 163296 originate from
new-born planets, we investigate if and under which circumstances the
gap-opening planets could represent progenitors of the exoplanet population
detected around A-type stars. In particular, we study the dependence of final
planetary masses and orbital parameters on the viscosity of the disk. The
evolution of the embedded planets was simulated throughout the disk lifetime
and up to 100 Myr after the dispersal of the disk, taking the evolving disk
structure and a likely range of disk lifetimes into account.
We find that the final configuration of the planets is largely determined by
the viscosity parameter of the disk and less dependent on the choice
for the disk lifetime and the initial planetary parameters. If we assume that
planets such as those in HD 163296 evolve to form the observed exoplanet
population of A-type stars, a parameter on the order of is required for the disks to induce
sufficiently high migration rates. Depending on whether or not future direct
imaging surveys will uncover a larger number of planets with and we expect
the parameter to be at the lower or upper end of this range, always
under the assumption that such disks indeed harbor wide orbit planets.Comment: Accepted for publication in Astronomy and Astrophysics, 13 pages, 7
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