Search results for "LSA"
showing 10 items of 832 documents
Levels and change in autonomous and controlled work motivation in older workers—The role of proximity to retirement and sense of community at work
2021
Previous studies suggest a preretirement disengagement process from work, which includes reduced work motivation. In this study, we investigated changes in autonomous and controlled work motivation over two years among participants of the Health, Aging and Retirement Transition in Sweden (HEARTS) study. We found stability in both types of motivation; however, those who retired after the study period showed more distinct declines in autonomous motivation. A stronger sense of community at work was related to level, but not change in autonomous motivation. Intra-individual fluctuations in the expected retirement age did not predict work motivation or vice versa. Future studies are needed to be…
Emotion rating from short blog texts
2008
Being able to automatically perceive a variety of emotions from text alone has potentially important applications in CMC and HCI that range from identifying mood from online posts to enabling dynamically adaptive interfaces. However, such ability has not been proven in human raters or computational systems. Here we examine the ability of naive raters of emotion to detect one of eight emotional categories from 50 and 200 word samples of real blog text. Using expert raters as a 'gold standard', naive-expert rater agreement increased with longer texts, and was high for ratings of joy, disgust, anger and anticipation, but low for acceptance and 'neutral' texts. We discuss these findings in ligh…
CONTRIBUTION OF PSEUDO-FOCUSED SOFT PROTONS TO THE BACKGROUND OF ATHENA
2021
This PhD thesis explores the role of low energy protons, the so-called ‘soft protons', as a component of the background in view of the future ESA's X-ray mission Athena. As a matter of fact, a high level of soft proton flux at the focal plane of Athena can adversely affect the scientific goals of the mission. To prevent this, a correct estimate of the soft proton flux expected at the focal plane of the satellite is fundamental. Such an estimate can be achieved only if the reflectivity of soft protons from the optics is well understood, with efforts on both the experimental and the theoretical sides. To this aim, I applied the model of reflectivity of particles at grazing incidence proposed …
The Be/X-ray transient 4U0115+63/V635 Cassiopeiae : II. Outburst mechanisms
2001
We present multi-wavelength long-term monitoring observations of V635 Cas, the optical counterpart to the transient X-ray pulsar 4U0115+63. The evolution of emission lines and photometric magnitudes indicates that the Be star undergoes relatively fast ( ~3 - 5yr) quasi-cyclic activity, losing and reforming its circumstellar disc. We show that the general optical, infrared and X-ray behaviour can be explained by the dynamical evolution of the viscous circumstellar disc around the Be star. After each disc-loss episode, the disc starts reforming and grows until it reaches the radius at which the resonant interaction of the neutron star truncates it. At some point, the disc becomes unstable to …
First observations of the X-ray transient EXO 2030+375 with IBIS/ISGRI
2003
We present a first INTEGRAL observation of the 42s transient X-ray pulsar EXO 2030+375 with IBIS/ISGRI. The source was detected during Cyg X-1 observations in December 2002. We analyzed observations during the outburst period from 9 to 21 December 2002 with a total exposure time of ~770 kiloseconds. EXO 2030+375 was almost always detected during single ~30 minute exposures in the 18-45 energy bands. The source light curve shows the characteristic outburst shape observed in this source.
Evolution in Recycling Scenario
2011
The recycling model argues the existence of an evolutionary connection between low mass X-ray binaries and radio millisecond pulsars. The main difficulties which this model finds in predict the parameters of the fully recycled millisecond pulsars, as mass and spin period, can be overcome by the onset of the so-called radio-ejection mechanism. This work is to provide observational support to the radio-ejection mechanism by inspecting the orbital and spin parameters of the known population of fully recycled radio pulsars and compare these with the expectation for the occurrence of this mechanism.
Discovery of a new accreting millisecond X-ray pulsar in the globular cluster NGC 2808
2016
We report on the discovery of coherent pulsations at a period of 2.9 ms from the X-ray transient MAXI J0911-655 in the globular cluster NGC 2808. We observed X-ray pulsations at a frequency of $\sim339.97$ Hz in three different observations of the source performed with XMM-Newton and NuSTAR during the source outburst. This newly discovered accreting millisecond pulsar is part of an ultra-compact binary system characterised by an orbital period of $44.3$ minutes and a projected semi-major axis of $\sim17.6$ lt-ms. Based on the mass function we estimate a minimum companion mass of 0.024 M$_{\odot}$, which assumes a neutron star mass of 1.4 M$_{\odot}$ and a maximum inclination angle of $75^{\…
The reflection component in NS LMXBs
2014
Thanks to the good spectral resolution and large effective area of the EPIC/PN instrument on board of XMM-Newton, we have at hand a large number of observations of accreting low-mass X-ray binaries, that allow for the fist time a comprehensive view on the characteristics of the reflection component at different accretion regimes and to probe the effects of a magnetosphere on its formation. We focus here on a comparative analysis of the reflection component from a series of spectroscopic studies on selected sources: 4U 1705-44, observed both in the soft and hard state, the pulsating ms pulsars SAX J1808.4-3658 and IGR J17511-3057, and the intermittent pulsar HETE J1900-2455. Although the sou…
Geographical developpment of the sports phenomenon : ruralization of practices or urbanization of the countrysides ? The alsatian sport movement betw…
1996
The diffusion of sports in the geographic space cannot be considered as having no incidence on their history. A study of the geographic development of the associative sports movement in Alsace between 1920 and 1940 reveals the variety of development modalities of the different sporting practices. As the sporting practice establishes itself in new (by their characteristics) local configurations of the geosystem, unprecedented ways of considering this practice appear.