806 research outputs found

    Comparison of prefrontal atrophy and episodic memory performance in dysexecutive Alzheimer’s disease and behavioural-variant frontotemporal dementia

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    Alzheimer’s disease (AD) sometimes presents with prominent executive dysfunction and associated prefrontal cortex atrophy. The impact of such executive deficits on episodic memory performance as well as their neural correlates in AD, however, remains unclear. The aim of the current study was to investigate episodic memory and brain atrophy in AD patients with relatively spared executive functioning (SEF-AD; n = 12) and AD patients with relatively impaired executive functioning (IEF-AD; n = 23). We also compared the AD subgroups with a group of behavioral-variant frontotemporal dementia patients (bvFTD; n = 22), who typically exhibit significant executive deficits, and age-matched healthy controls (n = 38). On cognitive testing, the three patient groups showed comparable memory profiles on standard episodic memory tests, with significant impairment relative to controls. Voxel-based morphometry analyses revealed extensive prefrontal and medial temporal lobe atrophy in IEF-AD and bvFTD, whereas this was limited to the middle frontal gyrus and hippocampus in SEF-AD. Moreover, the additional prefrontal atrophy in IEF-AD and bvFTD correlated with memory performance, whereas this was not the case for SEF-AD. These findings indicate that IEF-AD patients show prefrontal atrophy in regions similar to bvFTD, and suggest that this contributes to episodic memory performance. This has implications for the differential diagnosis of bvFTD and subtypes of AD

    Third Party Reports influence parents’ perceptions of coaching ability: Implications for youth sport coaches.

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    According to Olson, Roese, and Zanna’s (1996) Model of Expectancy Processes, information conveyed by others can determine our expectancies of people. Furthermore, Third Party Reports (TPRs) such as reputation may influence athletes’ initial expectancies of coaches (e.g., Manley et al., 2008; 2010; Thelwell et al., 2013). Parents are believed to play a fundamental role in the development of coach-athlete relationships (e.g., Jowett & Katchis, 2005) and, in turn, athletic achievement in youth sport (Gould et al., 2008). However, person perception research has not yet examined the impact of cues such as TPRs on the initial impressions and expectancies that parents form of youth sport coaches. The current study addresses this gap in the literature. Athletes’ parents viewed a hypothetical online report describing the appointment of a new coach at a local sports club. The report included a “comments” section, which consisted of “tweets” posted by the newly-appointed coach’s former athletes. Four experimental conditions were created by manipulating the coach’s level of warmth and competence (i.e., high vs. low) as reported through the “comments/tweets” (i.e., TPRs). After reading the online report, participants provided ratings of the coach’s ability using the Coaching Competency Questionnaire (Myers et al., 2006). Participants are currently being recruited via gatekeepers at sports clubs/organisations, as well as through social media. However, based on an initial sample (n = 83), Kruskal-Wallis tests typically revealed that high-warmth/high-competence TPRs resulted in highest evaluations of overall coaching ability, while TPRs low in both warmth and competence received poorest ratings. Interestingly, perceptions of Character-building Competence were highest for high-warmth/low-competence TPRs. These preliminary findings reveal that TPRs can influence parents’ perceptions of coaching proficiency, but that parents may value warmth over competence when assessing a coach’s ability to develop more holistic qualities in youth sport athletes

    Non-linear soil behavior on freight vs passenger lines

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    Upgrading existing passenger-only railway lines to carry freight traffic is becoming increasingly desirable. This is challenging because freight trains have larger axle loads and thus can have a negative effect on track longevity, particularly on ballasted lines supported by sub-optimal ground conditions. These additional loads can cause large subgrade strains resulting in non-linear behaviour, which should be considered before permitting freight vehicles on passenger routes. To do so requires the modelling of non-linear soil behaviour which is challenging. Therefore, this paper presents a solution in the form of an equivalent non-linear, thin layer element soil model, coupled to an analytical track model. The model has low computational demand and can adjust subgrade stiffness depending upon strain levels. Therefore, it is well suited to computing track response induced by freight trains. This paper validates the model and then uses it to compare the differences between the response of a ballasted line to freight and passenger vehicles

    Who bullies whom at a garden feeder? Interspecific agonistic interactions of small passerines during a cold winter

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    Interspecific agonistic interactions are important selective factors for maintaining ecological niches of different species, but their outcome is difficult to predict a priori. Here, we examined the direction and intensity of interspecific interactions in an assemblage of small passerines at a garden feeder, focussing on three finch species of various body sizes. We found that large and mediumsized birds usually initiated and won agonistic interactions with smaller species. Also, the frequency of fights increased with decreasing differences in body size between the participants. Finally, the probability of engaging in a fight increased with the number of birds at the feeder

    Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura: Trichodactylidae) at La Plata basin

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    Background: In inland water systems, it is important to characterize the trophic links in order to identify the ‘trophic species’ and, from the studies of functional diversity, understand the dynamics of matter and energy in these environments. The aim of this study is to analyze the natural diet of Trichodactylus kensleyi of subtropical rainforest streams and corroborate the temporal variation in the trophic activity during day hours. Results: A total of 15 major taxonomic groups were recognized in gut contents. The index of relative importance identified the following main prey items in decreasing order of importance: vegetal remains, oligochaetes, chironomid larvae, and algae. A significant difference was found in the amount of full stomachs during day hours showing a less trophic activity at midday and afternoon. The index of relative importance values evidenced the consumption of different prey according to day moments. Results of the gut content indicate that T. kensleyi is an omnivorous crab like other trichodactylid species. Opportunistic behavior is revealed by the ingestion of organisms abundant in streams such as oligochaetes and chironomid larvae. The consumption of allochthonous plant debris shows the importance of this crab as shredder in subtropical streams. However, the effective assimilation of plant matter is yet unknown in trichodactylid crabs. Conclusions: This research provides knowledge that complements previous studies about trophic relationships of trichodactylid crabs and supported the importance of T. kensleyi in the transference of energy and matter from benthic community and riparian sources to superior trophic levels using both macro- and microfauna.Fil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: de Azevedo Carvalho, Debora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

    The 2021 outburst of the recurrent nova RS Ophiuchi observed in X-rays by the Neil Gehrels Swift Observatory: a comparative study

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    On 2021 August 8, the recurrent nova RS Ophiuchi erupted again, after an interval of 15.5 yr. Regular monitoring by the Neil Gehrels Swift Observatory began promptly, on August 9.9 (0.37 day after the optical peak), and continued until the source passed behind the Sun at the start of November, 86 days later. Observations then restarted on day 197, once RS Oph emerged from the Sun constraint. This makes RS Oph the first Galactic recurrent nova to have been monitored by Swift throughout two eruptions. Here we investigate the extensive X-ray datasets from 2006 and 2021, as well as the more limited data collected by EXOSAT in 1985. The hard X-rays arising from shock interactions between the nova ejecta and red giant wind are similar following the last two eruptions. In contrast, the early super-soft source (SSS) in 2021 was both less variable and significantly fainter than in 2006. However, 0.3–1 keV light-curves from 2021 reveal a 35 s quasi-periodic oscillation consistent in frequency with the 2006 data. The Swift X-ray spectra from 2021 are featureless, with the soft emission typically being well parametrized by a simple blackbody, while the 2006 spectra showed much stronger evidence for superimposed ionized absorption edges. Considering the data after day 60 following each eruption, during the supersoft phase the 2021 spectra are hotter, with smaller effective radii and lower wind absorption, leading to an apparently reduced bolometric luminosity. We explore possible explanations for the gross differences in observed SSS behaviour between the 2006 and 2021 outbursts

    Belief Revision and Delusions: How Do Patients with Schizophrenia Take Advice?

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    The dominant cognitive model that accounts for the persistence of delusional beliefs in schizophrenia postulates that patients suffer from a general deficit in belief revision. It is generally assumed that this deficit is a consequence of impaired reasoning skills. However, the possibility that such inflexibility affects the entire system of a patient's beliefs has rarely been empirically tested. Using delusion-neutral material in a well-documented advice-taking task, the present study reports that patients with schizophrenia: 1) revise their beliefs, 2) take into account socially provided information to do so, 3) are not overconfident about their judgments, and 4) show less egocentric advice-discounting than controls. This study thus shows that delusional patients' difficulty in revising beliefs is more selective than had been previously assumed. The specificities of the task and the implications for a theory of delusion formation are discussed

    Legal determinants of external finance revisited : the inverse relationship between investor protection and societal well-being

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    This paper investigates relationships between corporate governance traditions and quality of life as measured by a number of widely reported indicators. It provides an empirical analysis of indicators of societal health in developed economies using a classification based on legal traditions. Arguably the most widely cited work in the corporate governance literature has been the collection of papers by La Porta et al. which has shown, inter alia, statistically significant relationships between legal traditions and various proxies for investor protection. We show statistically significant relationships between legal traditions and various proxies for societal health. Our comparative evidence suggests that the interests of investors may not be congruent with the interests of wider society, and that the criteria for judging the effectiveness of approaches to corporate governance should not be restricted to financial metrics

    A randomised controlled trial to determine the effect on response of including a lottery incentive in health surveys [ISRCTN32203485]

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    BACKGROUND: Postal questionnaires are an economical and simple method of data collection for research purposes but are subject to non-response bias. Several studies have explored the effect of monetary and non-monetary incentives on response. Recent meta-analyses conclude that financial incentives are an effective way of increasing response rates. However, large surveys rarely have the resources to reward individual participants. Three previous papers report on the effectiveness of lottery incentives with contradictory results. This study aimed to determine the effect of including a lottery-style incentive on response rates to a postal health survey. METHODS: Randomised controlled trial. Setting: North and West Birmingham. 8,645 patients aged 18 or over randomly selected from registers of eight general practices (family physician practices). Intervention: Inclusion of a flyer and letter with a health questionnaire informing patients that returned questionnaires would be entered into a lottery-style draw for £100 of gift vouchers. Control: Health questionnaire accompanied only by standard letter of explanation. Main outcome measures: Response rate and completion rate to questionnaire. RESULTS: 5,209 individuals responded with identical rates in both groups (62.1%). Practice, patient age, sex and Townsend score (a postcode based deprivation measure) were identified as predictive of response, with higher response related to older age, being female and living in an area with a lower Townsend score (less deprived). CONCLUSION: This RCT, using a large community based sample, found that the offer of entry into a lottery style draw for £100 of High Street vouchers has no effect on response rates to a postal health questionnaire
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