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131.
Unfortunately many of the numerous algorithms for computing the comulative distribution function (cdf) and noncentrality parameter
of the noncentral F and beta distributions can produce completely incorrect results as demonstrated in the paper by examples. Existing algorithms
are scrutinized and those parts that involve numerical difficulties are identified. As a result, a pseudo code is presented
in which all the known numerical problems are resolved. This pseudo code can be easily implemented in programming language
C or FORTRAN without understanding the complicated mathematical background.
Symbolic evaluation of a finite and closed formula is proposed to compute exact cdf values. This approach makes it possible
to check quickly and reliably the values returned by professional statistical packages over an extraordinarily wide parameter
range without any programming knowledge.
This research was motivated by the fact that a very useful table for calculating the size of detectable effects for ANOVA
tables contains suspect values in the region of large noncentrality parameter values compared to the values obtained by Patnaik’s
2-moment central-F approximation. The cause is identified and the corrected form of the table for ANOVA purposes is given. The accuracy of the
approximations to the noncentral-F distribution is also discussed.
The authors wish to thank Mr. Richárd Király for his preliminary work. The authors are grateful to the Editor and Associate
Editor of STCO and the unknown reviewers for their helpful suggestions. 相似文献
132.
Landscape urbanization threatens plant phylogenetic diversity in the Brazilian Atlantic Forest 总被引:1,自引:0,他引:1
Valdecir Silva-Junior Danielle G. Souza Rubens T. Queiroz Luiz G. R. Souza Elâine M. S. Ribeiro Bráulio A. Santos 《Urban Ecosystems》2018,21(4):625-634
Urbanization causes species loss around the world, but its effects on phylogenetic diversity are poorly known in tropical forests. Using a patch-landscape approach in an urbanizing region of the Brazilian Atlantic Forest, we tested whether the increase in landscape urbanization reduces plant species density, phylogenetic richness and divergence, and increases the relatedness among co-occurring individuals and species. We assessed plant responses to urbanization in adult (diameter at breast height?>?10 cm) and sapling communities (2.5–10 cm diameter) separately, as saplings are proxies of the future flora. We sampled 2860 woody plants belonging to 155 species in nine circular landscapes with urbanization level varying from 0% to 45%, and estimated the relatedness among the species that have increased and decreased in relative abundance in more urbanized landscapes (winner and losers, respectively). As expected, species density and phylogenetic richness decreased with the increase in urbanization. These responses were consistent for adult and sapling communities, suggesting a persistent loss of species and lineages in more urbanized landscapes. Contrary to our expectations, phylogenetic divergence and structure did not respond to urbanization, indicating that the more urbanized landscapes still retain much evolutionary history. However, because the relatedness among winners was greater than among losers, it is likely that the phylogenetic divergence gradually reduces and the relatedness increases, resulting in impoverished forests with uncertain ability to provide ecosystem services such as carbon storage and pest control. This environmental cost should be taken into account to align urban sprawl with biodiversity conservation. 相似文献
133.
Elena Berdasco‐Muñoz Léo‐Lyuki Nishibayashi Olivier Baud Valérie Biran Thierry Nazzi 《Infancy》2018,23(2):268-287
Infants born preterm have higher risks of developing linguistic deficits. Considering that the ability to segment words from fluent speech is crucial for lexical acquisition, Experiment 1 tested the ability of healthy extremely‐to‐late preterm infants to segment monosyllabic words at 6 months of postnatal age. Results establish basic segmentation skills in these infants. While we failed to find an effect of the degree of prematurity, this issue will need further exploration. Future studies will also have to specify the scope of these early segmentation skills, both in terms of the types of words segmented, the cues used to do so, and in terms of possible differences in performance between subgroups of preterm infants (e.g., based on gestational age or medical risks). Lastly, given that the preterm infants tested had a mean maturational age of 4 months, Experiment 2 explored monosyllabic segmentation in full‐term 4‐month olds. Infants succeeded at the task, providing the earliest developmental evidence of word segmentation in full‐term infants. These findings better specify the early trajectory of segmentation abilities in both full‐term and healthy, low‐risk preterm infants and support the proposal that prematurity might have a differential effect on the early acquisition of various linguistic levels. 相似文献
134.
Preschoolers are more likely to endorse testimony supported by strong arguments than by weak, circular ones. Two‐year‐olds exchange arguments with others, but no experiment has demonstrated that they are sensitive to information presented as argument. In the first phase of this study, 2‐year‐olds were shown ambiguous pictures—for instance a bird–fish hybrid—and asked what they thought the picture represented. An informant then contradicted them, providing either a strong argument, a circular argument, or no argument, and the children were asked what they now thought the hybrid was. The second phase was identical to the first, with new hybrids, except that the informant never provided any argument for her position. Finally, in the third phase, the informant left the room and the children were asked again to tell what the hybrids from the first two phases were. On the whole, there was an effect of the amount of information provided in the argument so that children were more likely to endorse labels provided by the informant who had supported her answer with a strong argument in the first phase. Moreover, they generalized the trust granted to informants who provided strong arguments. These results constitute the first experimental demonstration that 2‐year‐olds possess some argument evaluation skills. 相似文献
135.
David T. Kryszajtys Tara E. Hahmann Andrée Schuler Sarah Hamilton-Wright Carolyn P. Ziegler Flora I. Matheson 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2018,34(3):893-914
Despite many studies indicating an association between problem gambling and delinquent behaviours among adolescents, there has been no effort to systematically analyze the state of the literature on this relationship. To fill this gap, we conducted a scoping review of the literature published between 2000 and 2016 on problem gambling and delinquent behaviours among adolescents. We searched twelve databases and reviewed reference lists to identify eligible studies. Search terms included a combination of medical subject headings and keywords for gambling, youth, and delinquency, which were combined with the Boolean operator “AND”. 1795 studies were identified through the literature search. Nine studies were eligible for inclusion. All of the studies were conducted in North America, with primarily male participants, and most of the data were cross-sectional. No qualitative studies met the inclusion criteria. Screening tools used to measure problem gambling were inconsistent, making comparisons across studies difficult. We found a consistent moderate to strong association between problem gambling and delinquent behaviour. Only one study presented associations by socio-economic status and none considered gender, sex or ethnic differences. Studies in the review showed that problem gambling is associated with both violent and non-violent behaviours among adolescents. These associations may suggest that problem gambling and delinquent behaviours have common risk factors and reflect a syndrome of risky behaviours best targeted through prevention and treatment that is holistic and considers the context in which the youth is situated. Further research is warranted to better understand the relationship between problem gambling and delinquent behaviours. 相似文献
136.
Hibai Lopez-Gonzalez Frederic Guerrero-Solé Ana Estévez Mark Griffiths 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2018,34(3):709-726
The legalisation of online gambling in multiple territories has caused a growth in the exposure of consumers to online sports betting (OSB) advertising. While some efforts have been made to understand the visible structure of betting promotional messages, little is known about the latent components of OSB advertisements. The present study sought to address this issue by examining the metaphorical conceptualisation of OSB advertising. A sample of Spanish and British television OSB advertisements from 2014 to 2016 was analysed (N = 133). Following Lakoff and Johnson’s conceptual metaphor theory, four main structural metaphors that shaped how OSB advertising can be understood were identified: betting as (1) an act of love, (2) a market, (3) a sport, and (4) a natural environment. In general, these metaphors, which were found widely across 29 different betting brands, facilitated the perception of bettors as active players, with an executive role in the sport events bet upon, and greater control over bet outcomes. 相似文献
137.
David Lévesque Serge Sévigny Isabelle Giroux Christian Jacques 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2018,34(3):807-822
Despite numerous studies demonstrating the influence of cognitive distortions on gambling problem severity, empirical data regarding the role of psychological vulnerability on the latter is limited. Hence, this study assesses the mediating effect of cognitive distortions between psychological vulnerability (personality and mood), and gambling problem severity. It also verifies whether the relationships between these variables differs according to the preferred gambling activity. The sample is composed of 272 male gamblers [191 poker players; 81 video lottery terminal (VLT) players] aged between 18 and 82 years (M = 35.2). Bootstrap analysis results revealed that cognitive distortions mediate the effect of narcissism on gambling problem severity for both groups. The level of depression for VLT players significantly predicted gambling problem severity, both directly and indirectly via the mediating effect of cognitive distortions. Mediation analyses also indicated that narcissism had an indirect impact on problem gambling through cognitive distortions for both groups. These findings suggest that certain vulnerabilities related to personality and mood may influence cognitive distortion intensity and gambling problem severity. In addition, psychological vulnerabilities could differ based on preferred gambling activity. These results may be useful for prevention policies, identifying high risk gamblers and planning psychological interventions. 相似文献
138.
Sports betting advertising has arguably permeated contemporary sport consumption in many countries. Advertisements build narratives that represent situations and characters that normalize betting behaviour and raise public concerns regarding their detrimental effect on vulnerable groups. Adopting a grounded theory approach, the present study examined a British sample of sports betting advertisements (N = 102) from 2014 to 2016. The analysis revealed that individual themes aligned in a single core narrative, constructing a dual persuasive strategy of sports betting advertising: (i) to reduce the perceived risk involved in betting (with themes such as betting with friends, free money offers, humour, or the use of celebrities) while (ii) enhancing the perceived control of bettors (including themes of masculinity and sport knowledge). In addition, new technological features of sports betting platforms (e.g. live in-play betting) were used by advertisers to build narratives in which the ability to predict a sports outcome was overlapped by the ability of bettors to use such platforms, equalizing the ease of betting with the ease of winning. Based on the data analysed, it was concluded that the construction of a magnified idea of control in sports betting advertising is a cause for concern that requires close regulatory scrutiny. 相似文献
139.
140.
Ríos-Chelén Alejandro Ariel Cuatianquiz-Lima Cecilia Bautista Amando Martínez-Gómez Margarita 《Urban Ecosystems》2018,21(1):15-25
Urban Ecosystems - Vermilion flycatchers, a suboscine, sing songs with more elements in territories with higher urban noise levels. We tested the hypothesis that this pattern is achieved through... 相似文献