Search results for "variance"

What Do We Know About the Second Moment of Financial Markets?

2021

Recent research shows that the vast majority of scientific studies published in leading finance journals fails scientific replication (Hou, Xue, and Zhang, 2020; Harvey, Liu, and Zhu; 2016). This study argues that p-hacking, publication pressure and the selection bias from leading finance journals are perhaps not the underlying root cause for this issue. We show that standard methodologies often used in finance research are inevitably sample-specific due to the very nature of financial markets. While the consensus of earlier research postulates a rejection of the time-honored Levy hypothesis, our results strongly indicate that the variance of variance does not exist in any of the financial …

Assessment of Entrepreneurial Orientation in Vocational Training Students: Development of a New Scale and Relationships With Self-Efficacy and Person…

2019

Having emerged as an important concept in the organizational field, entrepreneurial orientation has also become a key idea in the context of education. Indeed, entrepreneurial education is now one of the common objectives for education and training systems in the European Union. Despite its importance, however, there is a scarcity of valid and reliable measures for assessing entrepreneurial orientation in students. The present study aimed to address this by developing and examining the psychometric properties of the Entrepreneurial Orientation Scale (EOS). A second objective is to study the relationships between entrepreneurial orientation and gender, self-efficacy, and personal initiative.…

The Schoolwork Engagement Inventory: Factorial Structure, Measurement Invariance by Gender and Educational Level, and Convergent Validity in Secondar…

2017

This study analyzes the dimensionality, reliability, metric invariance, and convergent validity of the Schoolwork Engagement Inventory (SEI) in secondary education. Participants in the study were 679 students in compulsory and post-compulsory secondary education in a large city in Eastern Spain during the 2014-2015 academic year. Confirmatory factor analysis (CFA) showed that the one-factor model of the SEI is superior to the other alternative models considered, providing an overall schoolwork engagement score in this educational stage. Reliability was also adequate and the instrument was found to be invariant by gender and educational level. Latent mean comparisons revealed a significant …

Measurement of the lifetime difference in the B$_s^0$ system

2005

We present a study of the decay B_s^0 -> J/psi phi We obtain the CP-odd fraction in the final state at time zero, R_perp = 0.16 +/- 0.10 (stat) +/- 0.02 (syst), the average lifetime of the (B_s, B_sbar) system, tau (B_s^0) =1.39^{+0.13}_{-0.16} (stat) ^{+0.01}_{-0.02} (syst) ps, and the relative width difference between the heavy and light mass eigenstates, Delta Gamma/Gamma = (Gamma_L - Gamma_H)/Gamma =0.24^{+0.28}_{-0.38} (stat) ^{+0.03}_{-0.04} (syst). With the additional constraint from the world average of the B_s^0$lifetime measurements using semileptonic decays, we find tau (B_s^0)= 1.39 +/- 0.06 ~ps and Delta Gamma/\Gamma = 0.25^{+0.14}_{-0.15}. For the ratio of the B_s^0 and B^0 li…

Experimental approach for testing the uncoupling between cardiovascular variability series

2002

In cardiovascular variability analysis, the significance of the coupling between two series is commonly assessed by defining a zero level on the magnitude-squared coherence (MSC). Although the use of the conventional value of 0.5 does not consider the dependence of MSC estimates on the analysis parameters, a theoretical threshold Tt is available only for the weighted covariance (WC) estimator. In this study, an experimental threshold for zero coherence Te was derived by a statistical test from the sampling distribution of MSC estimated on completely uncoupled time series. MSC was estimated by the WC method (Parzen window, spectral bandwidth B = 0.015, 0.02, 0.025, 0.03 Hz) and by the parame…

Linking functional and relational service quality to customer satisfaction and loyalty: differences between men and women.

2010

This study assessed differences between men and women in the association of perceptions of service quality with customer evaluations. Functional (efficiency with which the service is delivered) and relational (customers' emotional benefits, beyond the core performance, related to the social interaction of customers with employees) dimensions of service quality were measured as well as customer satisfaction and loyalty. The sample of 277 customers (191 men, 86 women), surveyed in 29 Mexican hotels, had a mean age of 38.1 yr. ( SD = 9.7) for men and 34.5 yr. ( SD = 11.0) for women. To be eligible for survey, customers had to have spent at least one night in the hotel in question. Analysis in…

Micrometeorological and sap flow measurement of energy and mass exchanges of woody crops in a Mediterranean environment

2011

Tracking multiple pathways of waste from a northern bluefin tuna farm in a marine-coastal area.

2011

Aquaculture of bluefin tuna in Mediterranean coastal waters has generated growing concern about the negative environmental effects. In the present isotopic study we examined the dispersal and fate of organic matter derived from a Mediterranean tuna farm in the surrounding environment. An overall enrichment in the heavy nitrogen isotope was found in the feed and in farmed tunas, indicating the input of isotopically traceable organic matter in the system. Waste was clearly traceable in the water column up to 1000 m from the cages, while only slight accumulation occurred in the sediment just below the cages. Waste was isotopically shown also to contribute to the diet of demersal and benthopela…

Seasonal screening of AChE, GSH and gonad histology, in European sea bassDicentrarchus labraxL. reared in three different fish farms

2013

The aim of this work was to do a preliminary seasonal screening of ecotoxicological biomarkers in European sea bass Dicentrarchus labrax in three different fish farms, to know if the different location and typology can discriminate them. A set of selected biomarkers of xenobiotic exposure, such as acetylcholinesterase (AChE) activity, Glutathione (GSH) and gonad morphology were investigated seasonally in male European sea bass D. labrax (L.) reared in three different intensive farms: a land-based farm of cement tanks (T), an in-shore sea cages farm (C1) and an off-shore sea cages farm (C2). The results showed that both location and typology can discriminate AChE activity, GSH content and go…

Thermal variance affects algal assemblage in rocky pools

2013

The intertidal rocky pools are habitats that, when disconnected from the sea, become highly stressful for sessile organisms such as algae. Algae experience wide changes of water temperature on short temporal scale (e. g. hour or lower) and their coverage and diversity are expected to depend on thermal variance of small water masses trapped at low tide. Here, we want to investigate the relationship between daily thermal variance and the composition, coverage and diversity of rocky pool’s algal community in Western Sicily (Southern MED). We chose 15 intertidal rocky pools and we deployed, in August 2012, thermo-loggers for two days to record temperature changes every 5-min (12 recordings per …