Search results for "duration"
showing 10 items of 447 documents
Deconstructing incubation behaviour in response to ambient temperature over different timescales
2021
Avian embryos need a stable thermal environment to develop optimally, while incubat-ing females need to allocate time to self-maintenance off the nest. In species with female-only incubation, eggs are exposed to ambient temperatures that usually cool them down during female absences. The lower the ambient temperature the sooner females should return to re-warm the eggs. When incubation constraints ease at increasing ambient temperatures, females respond by increasing either incubation effort or self-maintenance time. These responses are population-dependent even within the same species; but it is uncertain whether they are caused by local environmental conditions or they are an artefact fro…
Passive sound exposure induces rapid perceptual learning in musicians: event-related potential evidence.
2013
Musicians show enhanced auditory processing compared to nonmusicians. However, the neural basis underlying the effects of musical training on rapid plasticity in auditory processing has not been systematically studied. Here, the rapid (one session) learning-related plastic changes in event-related potential (ERP) responses for pitch and duration deviants between passive blocks were compared between musicians and nonmusicians. Passive blocks were interleaved with an active discrimination task. In addition to musicians having faster and stronger overall source activation for deviating sounds, source analysis revealed rapid plastic changes in the left and right temporal and left frontal source…
The Impact of Shadowing and the Severity of Fading on the First and Second Order Statistics of the Capacity of OSTBC MIMO Nakagami-Lognormal Channels
2011
Published version of an article in Wireless Personal Communications (2011), 1-16. Also available from the publisher at http://dx.doi.org/10.1007/s11277-011-0275-x This article presents a thorough statistical analysis of the capacity of orthogonal space-time block coded (OSTBC) multiple-input multiple-output (MIMO) Nakagami- lognormal (NLN) channels. The NLN channel model allows to study the joint effects of fast fading and shadowing on the statistical properties of the channel capacity. We have derived exact analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the capacity…
Media Effects: Cumulation and Duration
2017
The cumulation of media effects describes a process during which numerous (often, but not necessarily, small) effects accumulate over time as individuals use a certain medium or specific media contents repeatedly. Cumulative effects are especially central in forming individuals' perceptions of reality and are therefore a central premise in several theories and approaches that explain media effects (e.g., cultivation, agenda-setting, or spiral of silence). Whereas effects of single stimuli typically persist only in the short term, cumulative effects of media messages are long-term effects. This entry theorizes on the processes occurring between the short-term effects of a single stimulus and…
Marginal hazard ratio estimates in joint frailty models for heart failure trials
2019
Abstract This work is motivated by clinical trials in chronic heart failure disease, where treatment has effects both on morbidity (assessed as recurrent non‐fatal hospitalisations) and on mortality (assessed as cardiovascular death, CV death). Recently, a joint frailty proportional hazards model has been proposed for these kind of efficacy outcomes to account for a potential association between the risk rates for hospital admissions and CV death. However, more often clinical trial results are presented by treatment effect estimates that have been derived from marginal proportional hazards models, that is, a Cox model for mortality and an Andersen–Gill model for recurrent hospitalisations. …
Booms, Busts and normal times in the housing market
2015
We assess the existence of duration dependence in the likelihood of an end in housing booms, busts, and normal times. Using data for 20 industrial countries and a continuous-time Weibull duration model, we find evidence of positive duration dependence suggesting that housing market cycles have become longer over the last decades. Then, we extend the baseline Weibull model and allow for the presence of a change-point in the duration dependence parameter.We show that positive duration dependence is present in booms and busts that last less than 26 quarters, but that does not seem to be the case for longer phases of the housing market cycle. For normal times, no evidence of change-points is fo…
Degree course change and student performance: a mixed-effect approach
2015
This paper focuses on students credits earning speed over time and its determinants, dealing with the huge percentage of students who do not take the degree within the legal duration in the Italian University System. A new indicator for the performance of the student career is proposed on real data, concerning the cohort of students enrolled at a Faculty of the University of Palermo (followed for 7 years). The new indicator highlights a typical zero-inflated distribution and suggests to investigate the effect of the degree course (DC) change on the student career. A mixed-effect model for overdispersed data is considered, with the aim of taking into account the individual variability as wel…
Organization of Production Processes through the Multi-Service Method by Performing some Identical Operations of the same Duration and Structure
2013
Organisation of production processes, by means of multi service method refers to the performance of attributions within a working system, using simultaneously or successively more inputs or more items in a single means of production, by one or more employees. In the specifically chosen case, in order to outline the advantages that shall be obtained after implementing the multi service method, we want to illustrate a situation where there are the execution conditions of certain identical operations, with the same duration and structure, in which case the running time of the performer and the means of production will be identical. Serving multiple machines finds application in all industrial …
A Review of Early Numeracy Interventions for Children at Risk in Mathematics
2015
This study reviewed early numeracy interventions for four- to seven-year-old children at risk for mathematics difficulties. The search yielded 19 peer-reviewed studies with pre- and post-treatment control designs. The interventions were categorised as either core or supplemental instruction. The study analysed the effectiveness and identified the pedagogical components of the interventions: setting, duration, numeracy content used for intervention training and progress measurement, conductor and professional developmental support offered, and instructional design features. The interventions showed, to various degrees, the promising effect of improving the early numeracy skills of at-risk ch…
A person-environment-fit-model for temporary organizations - Antecedents for temporary working settings
2021
Abstract Projectification has led to the widespread use of temporary organizations (TOs) in many industries, but the various factors that determine successful work by employees in TOs are unexplored. We argue that organizations have different degrees of temporariness depending on the following five TO dimensions: temporal duration, nature of the task, team composition, hierarchy, and coordination. Considering the TO dimensions and varying degrees of temporariness, we propose a person-environment (P-E) fit model. The model comprises three levels – organizational-, group-, and job-oriented – and relates personal attributes to the TO dimensions. We contribute to theory by developing a set of p…