149 research outputs found

    Using eye movements to explore switch costs in working memory.

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    Updating object locations in working memory (WM) is faster when the same object is updated twice in a row compared to updating another object. In analogy to repetition priming effects in perceptual attention, this object-switch cost in WM is thought of as being due to the necessity to shift attention internally from one object to another. However, evidence for this hypothesis is only indirect. Here, we used eye tracking and a classic model of perceptual attention to get a more direct handle on the different processes underlying switch costs in spatial WM. Eye-movement data revealed three different contributors to switch costs. First, overt attention was attracted initially towards locations of the previously updated object. Second, longer fixation periods preceded eye movements between locations of different objects as compared to (previous and new) locations of the same object, most likely due to disengaging and reorienting focal attention between objects. Third, longer dwell times at the to-be-updated location preceded manual responses for switch updates as compared to repeats, probably indicating increased uncertainty between competing sources of activity after the actual attention shift. Results can easily be interpreted with existing (perceptual) attention models that propose competitive activation in an attention map for target objects

    Avoidance of tobacco health warnings? An eye-tracking approach.

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    Aims: Among three eye-tracking studies, we examined how cigarette pack features affected visual attention and self-reported avoidance of and reactance to warnings. Design: Study 1: smoking status × warning immediacy (short-term versus long-term health consequences) × warning location (top versus bottom of pack). Study 2: smoking status × warning framing (gain-framed versus loss-framed) × warning format (text-only versus pictorial). Study 3: smoking status × warning severity (highly severe versus moderately severe consequences of smoking). Setting: University of Bristol, UK, eye-tracking laboratory. Participants: Study 1: non-smokers (n = 25), weekly smokers (n = 25) and daily smokers (n = 25). Study 2: non-smokers (n = 37), smokers contemplating quitting (n = 37) and smokers not contemplating quitting (n = 43). Study 3: non-smokers (n = 27), weekly smokers (n = 26) and daily smokers (n = 26). Measurements: For all studies: visual attention, measured as the ratio of the number of fixations to the warning versus the branding, self-reported predicted avoidance of and reactance to warnings and for study 3, effect of warning on quitting motivation. Findings: Study 1: greater self-reported avoidance [mean difference (MD) = 1.14; 95% confidence interval (CI) = 0.94, 1.35, P  0.25). Study 3: greater self-reported avoidance of (MD = 0.37; 95% CI = 0.25, 0.48, P < 0.001, η p 2 = 0.33) and reactance to (MD = 0.14; 95% CI = 0.05, 0.23, P = 0.003, η p 2 = 0.11) highly severe warnings but findings were inconclusive as to whether there was a difference in visual attention (MD = –0.55; 95% CI = –1.5, 0.41, P = 0.24, η p 2 = 0.02). Conclusions: Subjective and objective (eye-tracking) measures of avoidance of health warnings on cigarette packs produce different results, suggesting these measure different constructs. Visual avoidance of warnings indicates low-level disengagement with warnings, while self-reported predicted avoidance reflects higher-level engagement with warnings

    Disturbed balance of expression between XIAP and Smac/DIABLO during tumour progression in renal cell carcinomas

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    Dysregulation of apoptosis plays an important role in tumour progression and resistance to chemotherapy. The X-linked inhibitor of apoptosis ( XIAP) is considered to be the most potent caspase inhibitor of all known inhibitor of apoptosis-family members. Only recently, an antagonist of XIAP has been identified, termed Smac/DIABLO. To explore the relevance of antiapoptotic XIAP and proapoptotic Smac/DIABLO for tumour progression in renal cell carcinomas (RCCs), we analysed XIAP and Smac/DIABLO mRNA and protein expression in the primary tumour tissue from 66 RCCs of all major histological types by quantitative real-time PCR, Western blot and ELISA. X-linked inhibitor of apoptosis and Smac/DIABLO mRNA expression was found in all RCCs. Importantly, the relative XIAP mRNA expression levels significantly increased from early (pT1) to advanced (pT3) tumour stages ( P = 0.0002) and also with tumour dedifferentiation ( P = 0.04). Western blot analysis confirmed the tumour stage-dependent increase of XIAP expression on the protein level. In contrast, mRNA and protein expression levels of Smac/DIABLO did not significantly change between early and advanced tumour stages or between low and high tumour grades. Consequently, the mRNA expression ratio between antiapoptotic XIAP and proapoptotic Smac/DIABLO markedly increased during progression from early ( pT1) to advanced ( pT3) tumour stages. Moreover, RCCs confined within the organ capsule ( pT1 and pT2) exhibited a significantly lower XIAP to Smac/DIABLO expression ratio when compared with RCCs infiltrating beyond the kidney ( pT3; P = 0.01). Thus, our investigation demonstrates that the delicate balance between XIAP and Smac/DIABLO expression is gradually disturbed during progression of RCCs, resulting in a relative increase of antiapoptotic XIAP over proapoptotic Smac/DIABLO, thereby probably contributing to the marked apoptosis resistance of RCC.OncologySCI(E)46ARTICLE71349-13579

    Quantitative proteomic analysis of the influence of lignin on biofuel production by Clostridium acetobutylicum ATCC 824

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    Background: Clostridium acetobutylicum has been a focus of research because of its ability to produce high-value compounds that can be used as biofuels. Lignocellulose is a promising feedstock, but the lignin–cellulose–hemicellulose biomass complex requires chemical pre-treatment to yield fermentable saccharides, including cellulose-derived cellobiose, prior to bioproduction of acetone–butanol–ethanol (ABE) and hydrogen. Fermentation capability is limited by lignin and thus process optimization requires knowledge of lignin inhibition. The effects of lignin on cellular metabolism were evaluated for C. acetobutylicum grown on medium containing either cellobiose only or cellobiose plus lignin. Microscopy, gas chromatography and 8-plex iTRAQ-based quantitative proteomic technologies were applied to interrogate the effect of lignin on cellular morphology, fermentation and the proteome. Results: Our results demonstrate that C. acetobutylicum has reduced performance for solvent production when lignin is present in the medium. Medium supplemented with 1 g L−1 of lignin led to delay and decreased solvents production (ethanol; 0.47 g L−1 for cellobiose and 0.27 g L−1 for cellobiose plus lignin and butanol; 0.13 g L−1 for cellobiose and 0.04 g L−1 for cellobiose plus lignin) at 20 and 48 h, respectively, resulting in the accumulation of acetic acid and butyric acid. Of 583 identified proteins (FDR < 1 %), 328 proteins were quantified with at least two unique peptides. Up- or down-regulation of protein expression was determined by comparison of exponential and stationary phases of cellobiose in the presence and absence of lignin. Of relevance, glycolysis and fermentative pathways were mostly down-regulated, during exponential and stationary growth phases in presence of lignin. Moreover, proteins involved in DNA repair, transcription/translation and GTP/ATP-dependent activities were also significantly affected and these changes were associated with altered cell morphology. Conclusions: This is the first comprehensive analysis of the cellular responses of C. acetobutylicum to lignin at metabolic and physiological levels. These data will enable targeted metabolic engineering strategies to optimize biofuel production from biomass by overcoming limitations imposed by the presence of lignin

    The severity of pandemic H1N1 influenza in the United States, from April to July 2009: A Bayesian analysis

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    Background: Accurate measures of the severity of pandemic (H1N1) 2009 influenza (pH1N1) are needed to assess the likely impact of an anticipated resurgence in the autumn in the Northern Hemisphere. Severity has been difficult to measure because jurisdictions with large numbers of deaths and other severe outcomes have had too many cases to assess the total number with confidence. Also, detection of severe cases may be more likely, resulting in overestimation of the severity of an average case. We sought to estimate the probabilities that symptomatic infection would lead to hospitalization, ICU admission, and death by combining data from multiple sources. Methods and Findings: We used complementary data from two US cities: Milwaukee attempted to identify cases of medically attended infection whether or not they required hospitalization, while New York City focused on the identification of hospitalizations, intensive care admission or mechanical ventilation (hereafter, ICU), and deaths. New York data were used to estimate numerators for ICU and death, and two sources of data - medically attended cases in Milwaukee or self-reported influenza-like illness (ILI) in New York - were used to estimate ratios of symptomatic cases to hospitalizations. Combining these data with estimates of the fraction detected for each level of severity, we estimated the proportion of symptomatic patients who died (symptomatic case-fatality ratio, sCFR), required ICU (sCIR), and required hospitalization (sCHR), overall and by age category. Evidence, prior information, and associated uncertainty were analyzed in a Bayesian evidence synthesis framework. Using medically attended cases and estimates of the proportion of symptomatic cases medically attended, we estimated an sCFR of 0.048% (95% credible interval [CI] 0.026%-0.096%), sCIR of 0.239% (0.134%-0.458%), and sCHR of 1.44% (0.83%-2.64%). Using self-reported ILI, we obtained estimates approximately 7-96lower. sCFR and sCIR appear to be highest in persons aged 18 y and older, and lowest in children aged 5-17 y. sCHR appears to be lowest in persons aged 5-17; our data were too sparse to allow us to determine the group in which it was the highest. Conclusions: These estimates suggest that an autumn-winter pandemic wave of pH1N1 with comparable severity per case could lead to a number of deaths in the range from considerably below that associated with seasonal influenza to slightly higher, but with the greatest impact in children aged 0-4 and adults 18-64. These estimates of impact depend on assumptions about total incidence of infection and would be larger if incidence of symptomatic infection were higher or shifted toward adults, if viral virulence increased, or if suboptimal treatment resulted from stress on the health care system; numbers would decrease if the total proportion of the population symptomatically infected were lower than assumed.published_or_final_versio

    Reconciling the biogeography of an invader through recent and historic genetic patterns: the case of topmouth gudgeon Pseudorasbora parva

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    © 2018 The Author(s) The genetic variability and population structure of introduced species in their native range are potentially important determinants of their invasion success, yet data on native populations are often poorly represented in relevant studies. Consequently, to determine the contribution of genetic structuring in the native range of topmouth gudgeon Pseudorasbora parva to their high invasion success in Europe, we used a dataset comprising of 19 native and 11 non-native populations. A total of 666 samples were analysed at 9 polymorphic microsatellite loci and sequenced for 597 bp of mitochondrial DNA. The analysis revealed three distinct lineages in the native range, of which two haplogroups were prevalent in China (100%), with a general split around the Qinling Mountains. Dating of both haplogroups closely matched past geological events. More recently, its distribution has been influenced by fish movements in aquaculture, resulting in gene flow between previously separated populations in Northern and Southern China. Their phylogeography in Europe indicate as few as two introductions events and two dispersal routes. Microsatellite data revealed native populations had higher genetic diversity than those in the invasive range, a contrast to previous studies on P. parva. This study confirms the importance of extensive sampling in both the native and non-native range of invasive species in evaluating the influence of genetic variability on invasion success

    Raising the Bar: Improving Methodological Rigour in Cognitive Alcohol Research

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    Background and Aims: A range of experimental paradigms claim to measure the cognitive processes underpinning alcohol use, suggesting that heightened attentional bias, greater approach tendencies and reduced cue-specific inhibitory control are important drivers of consumption. This paper identifies methodological shortcomings within this broad domain of research and exemplifies them in studies focused specifically on alcohol-related attentional bias. Argument and analysis: We highlight five main methodological issues: (i) the use of inappropriately matched control stimuli; (ii) opacity of stimulus selection and validation procedures; (iii) a credence in noisy measures; (iv) a reliance on unreliable tasks; and (v) variability in design and analysis. This is evidenced through a review of alcohol-related attentional bias (64 empirical articles, 68 tasks), which reveals the following: only 53% of tasks use appropriately matched control stimuli; as few as 38% report their stimulus selection and 19% their validation procedures; less than 28% used indices capable of disambiguating attentional processes; 22% assess reliability; and under 2% of studies were pre-registered. Conclusions: Well-matched and validated experimental stimuli, the development of reliable cognitive tasks and explicit assessment of their psychometric properties, and careful consideration of behavioural indices and their analysis will improve the methodological rigour of cognitive alcohol research. Open science principles can facilitate replication and reproducibility in alcohol research

    Ending on the scrap heap? The experience of job loss and job search among older workers

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    Job loss and unemployment are among the worst stressors that people can encounter during their lifetimes, and the search for (re-)employment is often a process troubled with setbacks and disappointments. While older workers are often shielded from job loss by higher tenure in their current organization, they might be struck particularly harshly when trying to find re-employment elsewhere. The current chapter combines earlier conceptual and empirical work on coping with job loss and job search with work on employability and the stereotypes that may turn the coping and job-search process into a severe challenge, particularly among older workers. For this purpose, we first outline the situation of older workers in the workforce, highlighting their vulnerability to possible job loss. We then draw on earlier conceptual work on job loss and on coping with job loss to depict a chronological process model of anticipation, job loss, and unemployment. In this model, we also consider the manifest and latent work functions that may be lost, the subsequent consequences for unemployed people’s psychological and physical health, and the different coping options available, particularly to older workers. In the end, older workers face an uphill battle when searching for re-employment, and one of our last sections outlines some actions that older workers might undertake to face the situation more successfully
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