670 research outputs found

    Performance And Satisfaction In Adaptive Websites: An Experiment On Searches Within A Task-Adapted Website

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    Finding information within websites is becoming an increasing challenge as the size and the complexity of websites soar. One possible solution is to adapt the view of the site to the task in hand. Although such a procedure is technically feasible, the effectiveness of such designs is yet to be tested. Assuming user scenarios that involve searches by browsing rather than structured queries, we build on models of searching in text to formulate a task representation of searches within websites. This task representation is used to model the effects of adapted websites on performance and satisfaction. We have, therefore, two main aims: (1) to propose a task representation of website searches, and (2) to use it to explore the effect of adaptive designs on performance and satisfaction. In an experiment with a simulated adaptive website, the impact of an adapted site is compared with that of a non-adapted site in terms of time, accuracy, and perceived complexity of completing a search task and satisfaction with the human-computer interaction. The results indicate that adapted sites improve performance but not overall satisfaction. A breakdown of the components of satisfaction reveals that users are unhappy with the changing menus. Part of the explanation may be their perceptions that adaptive sites are less consistent and, therefore, more complex

    Causes of Death Following PCI Versus CABG in Complex CAD 5-Year Follow-Up of SYNTAX

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    AbstractBackgroundThere are no data available on specific causes of death from randomized trials that have compared coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI).ObjectivesThe purpose of this study was to investigate specific causes of death, and its predictors, after revascularization for complex coronary disease in patients.MethodsAn independent Clinical Events Committee consisting of expert physicians who were blinded to the study treatment subclassified causes of death as cardiovascular (cardiac and vascular), noncardiovascular, or undetermined according to the trial protocol. Cardiac deaths were classified as sudden cardiac, related to myocardial infarction (MI), and other cardiac deaths.ResultsIn the randomized cohort, there were 97 deaths after CABG and 123 deaths after PCI during a 5-year follow-up. After CABG, 49.4% of deaths were cardiovascular, with the greatest cause being heart failure, arrhythmia, or other causes (24.6%), whereas after PCI, the majority of deaths were cardiovascular (67.5%) and as a result of MI (29.3%). The cumulative incidence rates of all-cause death were not significantly different between CABG and PCI (11.4% vs. 13.9%, respectively; p = 0.10), whereas there were significant differences in terms of cardiovascular (5.8% vs. 9.6%, respectively; p = 0.008) and cardiac death (5.3% vs. 9.0%, respectively; p = 0.003), which were caused primarily by a reduction in MI-related death with CABG compared with PCI (0.4% vs. 4.1%, respectively; p <0.0001). Treatment with PCI versus CABG was an independent predictor of cardiac death (hazard ratio: 1.55; 95% confidence interval: 1.09 to 2.33; p = 0.045). The difference in MI-related death was seen largely in patients with diabetes, 3-vessel disease, or high SYNTAX (TAXUS Drug-Eluting Stent Versus Coronary Artery Bypass Surgery for the Treatment of Narrowed Arteries) trial scores.ConclusionsDuring a 5-year follow-up, CABG in comparison with PCI was associated with a significantly reduced rate of MI-related death, which was the leading cause of death after PCI. Treatments following PCI should target reducing post-revascularization spontaneous MI. Furthermore, secondary preventive medication remains essential in reducing events post-revascularization. (TAXUS Drug-Eluting Stent Versus Coronary Artery Bypass Surgery for the Treatment of Narrowed Arteries [SYNTAX]; NCT00114972

    Beliefs and desires in the predictive brain

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    Bayesian brain theories suggest that perception, action and cognition arise as animals minimise the mismatch between their expectations and reality. This principle could unify cognitive science with the broader natural sciences, but leave key elements of cognition and behaviour unexplained

    Control of wrist movement in deafferented man: evidence for a mixed strategy of position and amplitude control

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    © 2017 The Author(s) There is a continuing debate about control of voluntary movement, with conflicted evidence about the balance between control of movement vectors (amplitude control) that implies knowledge of the starting position for accuracy, and equilibrium point or final position control, that is independent of the starting conditions. We tested wrist flexion and extension movements in a man with a chronic peripheral neuronopathy that deprived him of proprioceptive knowledge of his wrist angles. In a series of experiments, we demonstrate that he could scale the amplitude of his wrist movements in flexion/extension, even without visual feedback, and appeared to adopt a strategy of moving via a central wrist position when asked to reach target angles from unknown start locations. When examining the relationship between positional error at the start and end of each movement in long sequences of movements, we report that he appears to have three canonical positions that he can reach relatively successfully, in flexion, in extension and in the centre. These are consistent with end-point or position control. Other positions were reached with errors that suggest amplitude control. Recording wrist flexor and extensor EMG confirmed that the flexion and extension canonical positions were reached by strong flexor and extensor activity, without antagonist activity, and other positions were reached with graded muscle activation levels. The central canonical position does not appear to be reached by either maximal co-contraction or by complete relaxation, but may have been reached by matched low-level co-contraction

    The Ets dominant repressor En/Erm enhances intestinal epithelial tumorigenesis in ApcMin mice

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    <p>Abstract</p> <p>Background</p> <p>Ets transcription factors have been widely implicated in the control of tumorigenesis, with most studies suggesting tumor-promoting roles. However, few studies have examined Ets tumorigenesis-modifying functions <it>in vivo </it>using model genetic systems.</p> <p>Methods</p> <p>Using mice expressing a previously characterized Ets dominant repressor transgene in the intestinal epithelium (Villin-En/Erm), we examined the consequences of blocking endogenous Ets-mediated transcriptional activation on tumorigenesis in the Apc<sup>Min </sup>model of intestinal carcinoma.</p> <p>Results</p> <p>En/Erm expression in the intestine, at levels not associated with overt crypt-villus dysmorphogenesis, results in a marked increase in tumor number in Apc<sup>Min </sup>animals. Moreover, when examined histologically, tumors from En/Erm-expressing animals show a trend toward greater stromal invasiveness. Detailed analysis of crypt-villus homeostasis in these En/Erm transgenic animals suggests increased epithelial turnover as one possible mechanism for the enhanced tumorigenesis.</p> <p>Conclusion</p> <p>Our findings provide <it>in vivo </it>evidence for a tumor-restricting function of endogenous Ets factors in the intestinal epithelium.</p

    Ecological expected utility and the mythical neural code

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    Neural spikes are an evolutionarily ancient innovation that remains nature’s unique mechanism for rapid, long distance information transfer. It is now known that neural spikes sub serve a wide variety of functions and essentially all of the basic questions about the communication role of spikes have been answered. Current efforts focus on the neural communication of probabilities and utility values involved in decision making. Significant progress is being made, but many framing issues remain. One basic problem is that the metaphor of a neural code suggests a communication network rather than a recurrent computational system like the real brain. We propose studying the various manifestations of neural spike signaling as adaptations that optimize a utility function called ecological expected utility

    Values clarification in a decision aid about fertility preservation: does it add to information provision?

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    Background We aimed to evaluate the effect of a decision aid (DA) with information only compared to a DA with values clarification exercise (VCE), and to study the role of personality and information seeking style in DA-use, decisional conflict (DC) and knowledge. Methods Two scenario-based experiments were conducted with two different groups of healthy female participants. Dependent measures were: DC, knowledge, and DA-use (time spent, pages viewed, VCE used). Respondents were randomized between a DA with information only (VCE-) and a DA with information plus a VCE(VCE+) (experiment 1), or between information only (VCE-), information plus VCE without referral to VCE(VCE+), and information plus a VCE with specific referral to the VCE, requesting participants to use the VCE(VCE++) (experiment 2). In experiment 2 we additionally measured personality (neuroticism/conscientiousness) and information seeking style (monitoring/blunting). Results Experiment 1. There were no differences in DC, knowledge or DA-use between VCE- (n=70) and VCE+ (n=70). Both DAs lead to a mean gain in knowledge from 39% at baseline to 73% after viewing the DA. Within VCE+, VCE-users (n=32, 46%) reported less DC compared to non-users. Since there was no difference in DC between VCE- and VCE+, this is likely an effect of VCE-use in a self-selected group, and not of the VCE per se. Experiment 2. There were no differences in DC or knowledge between VCE- (n=65), VCE+ (n=66), VCE++ (n=66). In all groups, knowledge increased on average from 42% at baseline to 72% after viewing the DA. Blunters viewed fewer DA-pages (R=0.38, p<.001). More neurotic women were less certain (R=0.18, p<.01) and felt less supported in decision making (R=0.15, p<.05); conscientious women felt more certain (R=-0.15, p<.05) and had more knowledge after viewing the DA (R=0.15, p<.05). Conclusions Both DAs lead to increased knowledge in healthy populations making hypothetical decisions, and use of the VCE did not improve knowledge or DC. Personality characteristics were associated to some extent with DA-use, information seeking styles with aspects of DC. More research is needed to make clear recommendations regarding the need for tailoring of information provision to personality characteristics, and to assess the effect of VCE use in actual patients

    Bacteremic community-acquired pneumonia due to Klebsiella pneumoniae: Clinical and microbiological characteristics in Taiwan, 2001-2008

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    <p>Abstract</p> <p>Background</p> <p><it>Klebsiella pneumoniae </it>is the major cause of community-acquired pyogenic infections in Taiwan. This retrospective study evaluated the clinical and microbiological characteristics of bacteremic community-acquired pneumonia due to <it>K. pneumoniae </it>in Taiwanese adults.</p> <p>Methods</p> <p>The clinical characteristics of bacteremic community-acquired pneumonia (CAP) in adults due to <it>K. pneumoniae </it>were compared to those of adults with bacteremic CAP due to <it>Streptococcus pneumoniae </it>at a tertiary medical center in Taiwan from 2001-2008. Risk factors for mortality of bacteremic CAP due to <it>K. pneumoniae </it>were analyzed. All clinical isolates of <it>K. pneumoniae </it>were examined for capsular serotypes, hypermucoviscosity phenotype, aerobactin and <it>rmpA </it>gene.</p> <p>Results</p> <p><it>K. pneumoniae </it>was the dominant cause of bacteremic CAP and was associated with a more fulminant course and a worse prognosis than bacteremic CAP due to <it>Streptococcus pneumoniae</it>. Initial presentation with septic shock and respiratory failure were independent risk factors for both early and total mortality. Serotype K1 and K2 comprised around half of all isolates. There were no significant differences in the clinical characteristics of patients with bacteremic CAP due to K1/K2 and non-K1/K2 isolates. Hypermucoviscosity phenotype as well as the aerobactin and <it>rmpA </it>genes were highly prevalent in the <it>K. pneumoniae </it>isolates.</p> <p>Conclusions</p> <p><it>K. pneumoniae </it>continued to be the dominant cause of bacteremic CAP in Taiwanese adults during 2001-2008. Initial presentation with septic shock and respiratory failure were independent risk factors for both early and total mortality from <it>K. pneumoniae </it>bacteremic CAP. Serotypes K1/K2 comprised around half of all isolates, but did not predispose patients to a poor clinical outcome. Physicians should be aware of the poor prognosis of any patient with bacteremic <it>K. pneumoniae </it>CAP and monitor these patients more closely.</p
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