Search results for "duration"
showing 10 items of 447 documents
Macroecological properties of ammonites : spatial distribution, phylogeny, and faunal similarity
2016
The present work, which lies between macroecology and macroevolution, focuses on the spatio-temporal dynamics of early Pliensbachian ammonites of the western Tethys. Two main questions are addressed: how does inter-assemblage compositional similarity decrease with geographical distance? What is the relationship between species range size and phylogeny, species duration and latitudinal position?Ammonite dispersal dynamics are studied through a multi-scale Similarity Distance Decay analysis. We show that their long-distance dispersal is facilitated when the environment is more homogeneous and that it is not related to their morphology. This suggests that their long-distance dispersal occurred…
The Influence of Sports on Cognitive Task Performance – A Critical Overview
2013
The potential effect of different methods on cognitive performance is of great interest to scientific researchers. In addition to drugs, nutrition and sleeping behavior, extensive research has focused on different kinds of sports and exercise and their potential to enhance cognitive task performance. In this chapter, I will give the reader an overview of studies dealing with athletic activities of healthy people and their effects on cognitive task performance. Furthermore, I present and discuss limitations and problems found in these studies. One problem that I point out that makes the comparison of the study results difficult is the heterogeneous study design regarding mode, duration and i…
Fate of aerobic granular sludge in the long-term: The role of EPSs on the clogging of granular sludge porosity
2016
This work aims to investigate the stability of aerobic granular sludge in the long term, focusing on the clogging of the granular sludge porosity exerted by the extracellular polymeric substances (EPSs). The effects of different cycle lengths (short and long-term cycle) on the granular sludge stability were investigated. Results obtained outlined that during the short duration cycle, the formation and breakage of the aerobic granules were continuously observed. During this period, the excess of EPS production contributed to the clogging of the granules porosity, causing their breakage in the long run. During the long-duration cycle, the extended famine period entailed a greater EPSs consump…
Applying systematic review search methods to the grey literature: a review of education and training courses on breastfeeding support for health prof…
2021
Abstract Background Currently, lactation training courses aimed at health professionals are important for informing and supporting mothers who are breastfeeding. In this review, we seek to analyze similarities and/or variations in course content, modes of delivery, costs, teaching style and learning strategies among courses. To our knowledge, a review of lactation training courses available worldwide is lacking. Thus, the aim of this review is to describe course models aimed at training health professionals in lactation support for mothers. Methods Through searching grey literature, training courses were obtained from several directories, including the Alaska Breastfeeding Coalition, Intern…
Sub-200-kHz single soliton generation in a long ring Er-fiber laser with strict polarization control by using twisted fiber
2020
Abstract In the present work we demonstrate a novel single-soliton ultra-low pulse repetition frequency passively mode-locked erbium-doped fiber laser. We mitigate the residual linear birefringence of fiber by fiber twist to achieve a strict control of polarization. For mode-locking the nonlinear polarization rotation (NPR) was used. Special technique was applied to reduce the overdriving of NPR that allows the generation of single soliton in ultra-long cavity. The strict control of polarization yields a stable relation between the polarization state of the pulses propagating in the cavity and the regimes of generation. A 192.12-kHz train of soliton pulses was obtained with pulse duration o…
Flashlamp-pumped Nd:KGW laser in MOPA configuration: comparative study of several rods
1999
The laser performance of the Nd:KGW crystal has been studied in a master oscillator and power amplifier configuration (MOPA). Several crystals from two different producers were investigated for the oscillator and the amplifier. A maximum single-pass gain of 25 was observed in free-running and Q-switched mode. We obtained a maximum output amplified energy of 400 mJ at 30 Hz (with a pulse duration of 10 to 30 ns) with a divergence less than 3 mrad. We also studied the limitations of this configuration due to the very high gain of the Nd:KGW crystal.
Early DEtection of wEaring off in Parkinson disease: The DEEP study
2014
Assessing the frequency of Wearing-Off (WO) in Parkinson's disease (PD) patients, and its impact on Quality of Life (QoL). METHODS: Consecutive ambulatory patients, who were on dopaminergic treatment for ≥ 1 year, were included in this multicentre, observational cross-sectional study. In a single visit, WO was diagnosed based on neurologist assessment as well as using the validated Italian version of a patient self-rated 19-question Wearing-Off Questionnaire (WOQ-19); WO was defined for scores ≥ 2. QoL was evaluated by the 8-item Parkinson's Disease Questionnaire (PDQ-8). RESULTS: 617 subjects were included, with a mean anti-Parkinson treatment duration of 6.6 ± 4.6 years, 87.2% were on lev…
Structural properties of the range-II- and range-III order in amorphous-SiO2 probed by electron paramagnetic resonance and Raman spectroscopy
2010
In the present work we report an experimental investigation by electron paramagnetic resonance spectroscopy on the hyperfine structure of the E. point defect, probing the local arrangement of the network (range-II order), and by Raman spectroscopy on the D 1 and D 2 lines, probing mean features of the network (range-III order). Our studies, performed on a-SiO 2 samples thermally treated at 1000 °C in air for different time durations, show that changes of the hyperfine structure and of the D 1 and D 2 lines occur in a correlated way. These results give strong evidence that the range-II and range-III order properties are intimately related to each other and that these properties are determine…
Two-color ionization of hydrogen by short intense pulses
2010
Photoelectron energy spectra resulting by the interaction of hydrogen with two short pulses having carrier frequencies, respectively, in the range of the infrared and XUV regions have been calculated. The effects of the pulse duration and timing of the X-ray pulse on the photoelectron energy spectra are discussed. Analysis of the spectra obtained for very long pulses show that certain features may be explained in terms of quantum interferences in the time domain. It is found that, depending on the duration of the X-ray pulse, ripples in the energy spectra separated by the infrared photon energy may appear. Moreover, the temporal shape of the low frequency radiation field may be inferred by …
Rational Poverty or Poor Rationality? The Take‐up of Social Assistance Benefits
2001
In several countries social assistance dependence has been increasing since the 1980s. After surveying the theoretical and empirical take-up literature, this study presents estimates of recent rates of non take-up of social assistance benefits. Once methodological shortcomings of prior estimations are corrected, the results show that take-up has fallen recently and thus cannot explain the rising welfare receipt. Following theoretical predictions, the probability that a rational individual takes up social assistance increases with the expected benefit amount and duration, and falls with application cost and stigma. More than half of all households eligible for transfers under the German soci…