166 research outputs found
Fractionally Integrated Moving Average Stable Processes With Long-Range Dependence
Long memory processes driven by L\'evy noise with finite second-order moments
have been well studied in the literature. They form a very rich class of
processes presenting an autocovariance function which decays like a power
function. Here, we study a class of L\'evy process whose second-order moments
are infinite, the so-called -stable processes. Based on Samorodnitsky
and Taqqu (2000), we construct an isometry that allows us to define stochastic
integrals concerning the linear fractional stable motion using
Riemann-Liouville fractional integrals. With this construction, follows
naturally an integration by parts formula. We then present a family of
stationary processes with the property of long-range dependence,
using a generalized measure to investigate its dependence structure. In the
end, the law of large number's result for a time's sample of the process is
shown as an application of the isometry and integration by parts formula
Torn between two targets: German police officers talk about the use of force
Considering earlier research into police use of force as well as the judicial and practical frame of police work in Germany, the article presents the results of an empirical study on the individual and collective legitimization of the use of force by German police officers. There are numerous justifications for the use of force expressed by focus group participants in eight German Federal States who were responding to a hypothesized scenario. In the discussions observed within the groups, reference is first made to the stateâs duty to prosecute alleged offences and the measures or formal actions to do thisâhence, the legal authority to use force. In the course of the discussions, however, it became obvious that illegal violence may occur, although it was not perceived as such by the officers. Overall, and after an intensive analysis of the focus group discussions, it can be stated that use of force (whether legal or not) depends on the police officerâs perception of the resistance of the person being engaged with. In this regard, different socialâcultural or physicalâmaterial factors can be identified. They have different influences on the individual legitimization of police actions, intertwined with the perception of the situation as constructed by the officer. Three ways of perceiving the situation can be deduced, resulting in different patterns of justification for the use of force
Estimation of genetic parameters for test-day milk yield in Girolando cows using a random regression model.
The objective of this study was to estimate the components of variance and genetic parameters of test-day milk yield in first lactation Girolando cows, using a random regression model. A total of 126,892 test-day milk yield (TDMY) records of 15,351 first-parity Holstein, Gyr, and Girolando breed cows were used, obtained from the Associação Brasileira dos Criadores de Girolando. To estimate the components of (co) variance, the additive genetic functions and permanent environmental covariance were estimated by random regression in three functions: Wilmink, Legendre Polynomials (third order) and Linear spline Polynomials (three knots). The Legendre polynomial function showed better fit quality. The genetic and permanent environment variances for TDMY ranged from 2.67 to 5.14 and from 9.31 to 12.04, respectively. Heritability estimates gradually increased from the beginning (0.13) to mid-lactation (0.19). The genetic correlations between the days of the control ranged from 0.37 to 1.00. The correlations of permanent environment followed the same trend as genetic correlations. The use of Legendre polynomials via random regression model can be considered as a good tool for estimating genetic parameters for test-day milk yield records
Power Hardware In The Loop Validation of Fault Ride Through of VSC HVDC Connected Offshore Wind Power Plants
Researching the use of force: The background to the international project
This article provides the background to an international project on use of force by the police that was carried out in eight countries. Force is often considered to be the defining characteristic of policing and much research has been conducted on the determinants, prevalence and control of the use of force, particularly in the United States. However, little work has looked at police officersâ own views on the use of force, in particular the way in which they justify it. Using a hypothetical encounter developed for this project, researchers in each country conducted focus groups with police officers in which they were encouraged to talk about the use of force. The results show interesting similarities and differences across countries and demonstrate the value of using this kind of research focus and methodology
Health Outcome Predictive Evaluation for COVID 19 international registry (HOPE COVID-19), rationale and design
The disease produced by the new coronavirus known as SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), named COVID-19 (Coronavirus Disease-2019) has recently been classified as a pandemic by the World Health Organization (WHO). However, scarce clinical data is available and generally limited to the Chinese population due to the first cases were identified in Wuhan (Hubei, China).This article describes the rationale and design of the HOPE COVID-19 (Health Outcome Predictive Evaluation for COVID 19) registry (ClinicalTrials.gov Identifier: NCT04334291). With an ambispective cohort design, eligible patients are those discharged, deceased or alive, from any hospital center with a confirmed diagnosis or a COVID-19 high suspicion. With a current recruitment of more than 7000 cases, in 46 hospitals in 8 countries, since it is not possible to estimate the sample size based on literature reports, the investigators will try to get the maximum numbers of patients possible. The study primary objective is all cause mortality and aims to characterize the clinical profile of patients infected in order to develop a prognostic clinical score allowing, rapid logistic decision making. As secondary objectives, the analysis of other clinical events, the risk-adjusted influence of treatments and previous comorbidities of patients infected with the disease will be performed.The results of HOPE COVID-19 will contribute to a better understanding of this condition. We aim to describe the management of this condition as well as the outcomes in relation to the therapy chosen, in order to gain insight into improving patient care in the coming months. Clinical Trial registration: ClinicalTrials.gov. Unique identifier: NCT04334291
âThe only game in town?â: football match-fixing in Greece
The final publication is available at Springer via http://dx.doi.org/10.1007/s12117-014-9239-3Football match-fixing in Greece has a relatively long history, however, from the late 1990s it has been considered as a serious problem for the sport in the country. Despite the history of the phenomenon in the country, Greece has only relatively recently been identified as one of the hotspots for football match-fixing on an international level. Following the recent scandal exposure of fixed matches in Greece in 2011, also known as Koriopolis (a pun name on the Italian scandal Calciopolis and the Greek word âkoriosâ or phone-tap), detailed information about numerous matches played in the 2008/09, 2009/10 and 2010/11 seasons that attracted UEFAâs attention were brought into the public eye. Soon after, legal action was taken against individuals involved in the process, with a number of club officials facing lifelong bans from any footballrelated activity, and football clubs either relegated or excluded from European competitions and the Super League itself for their involvement in the scandal. In May 2013, the number of people facing charges exceeded 200, with some of them having already been imprisoned for their involvement in the scandal. Following the aforementioned scandal exposure, a vast amount of information regarding football match-fixing was made available to the public. The aim of the current article is to provide an account of the social organisation of football match-fixing in Greece. Our account is based on three main sources of data: the telephone conversations that were the result of wiretapping by the National Intelligence Agency in relation to the latest football match-fixing scandal (of 2011), published media sources, and interviews with informed actors from the realm of Greek football
Vertebral body stenting: a new method for vertebral augmentation versus kyphoplasty
Vertebroplasty and kyphoplasty are well-established minimally invasive treatment options for compression fractures of osteoporotic vertebral bodies. Possible procedural disadvantages, however, include incomplete fracture reduction or a significant loss of reduction after balloon tamp deflation, prior to cement injection. A new procedure called âvertebral body stentingâ (VBS) was tested in vitro and compared to kyphoplasty. VBS uses a specially designed catheter-mounted stent which can be implanted and expanded inside the vertebral body. As much as 24 fresh frozen human cadaveric vertebral bodies (T11-L5) were utilized. After creating typical compression fractures, the vertebral bodies were reduced by kyphoplasty (n = 12) or by VBS (n = 12) and then stabilized with PMMA bone cement. Each step of the procedure was performed under fluoroscopic control and analysed quantitatively. Finally, static and dynamic biomechanical tests were performed. A complete initial reduction of the fractured vertebral body height was achieved by both systems. There was a significant loss of reduction after balloon deflation in kyphoplasty compared to VBS, and a significant total height gain by VBS (mean ± SD in %, p < 0.05, demonstrated by: anterior height loss after deflation in relation to preoperative height [kyphoplasty: 11.7 ± 6.2; VBS: 3.7 ± 3.8], and total anterior height gain [kyphoplasty: 8.0 ± 9.4; VBS: 13.3 ± 7.6]). Biomechanical tests showed no significant stiffness and failure load differences between systems. VBS is an innovative technique which allows for the possibly complete reduction of vertebral compression fractures and helps maintain the restored height by means of a stent. The height loss after balloon deflation is significantly decreased by using VBS compared to kyphoplasty, thus offering a new promising option for vertebral augmentation
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