516 research outputs found

    Dogs distinguish human intentional and unintentional action

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    When dogs interact with humans, they often show appropriate reactions to human intentional action. But it is unclear from these everyday observations whether the dogs simply respond to the action outcomes or whether they are able to discriminate between different categories of actions. Are dogs able to distinguish intentional human actions from unintentional ones, even when the action outcomes are the same? We tested dogs’ ability to discriminate these action categories by adapting the so-called “Unwilling vs. Unable” paradigm. This paradigm compares subjects’ reactions to intentional and unintentional human behaviour. All dogs received three conditions: In the unwilling-condition, an experimenter intentionally withheld a reward from them. In the two unable-conditions, she unintentionally withheld the reward, either because she was clumsy or because she was physically prevented from giving the reward to the dog. Dogs clearly distinguished in their spontaneous behaviour between unwilling- and unable-conditions. This indicates that dogs indeed distinguish intentional actions from unintentional behaviour. We critically discuss our findings with regard to dogs’ understanding of human intentional action.Results - Analysis of waiting - Other behavioural reactions Discussion Methods - Ethical statement - Subjects - Experimental set‑up - Procedure - Codin

    Density functional theory calculations and vibrational spectroscopy on iron spin-crossover compounds

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    Iron complexes with a suitable ligand field undergo spin-crossover (SCO), which can be induced reversibly by temperature, pressure or even light. Therefore, these compounds are highly interesting candidates for optical information storage, for display devices and pressure sensors. The SCO phenomenon can be conveniently studied by spectroscopic techniques like Raman and infrared spectroscopy as well as nuclear inelastic scattering, a technique which makes use of the M\"ossbauer effect. This review covers new developments which have evolved during the last years like, e.g. picosecond infrared spectroscopy and thin film studies but also gives an overviewon newtechniques for the theoretical calculation of spin transition phenomena and vibrational spectroscopic data of SCO complexes

    Elucidating the structural composition of a Fe-N-C catalyst by nuclear and electron resonance techniques

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    Fe–N–C catalysts are very promising materials for fuel cells and metal–air batteries. This work gives fundamental insights into the structural composition of an Fe–N–C catalyst and highlights the importance of an in‐depth characterization. By nuclear‐ and electron‐resonance techniques, we are able to show that even after mild pyrolysis and acid leaching, the catalyst contains considerable fractions of α‐iron and, surprisingly, iron oxide. Our work makes it questionable to what extent FeN4 sites can be present in Fe–N–C catalysts prepared by pyrolysis at 900 °C and above. The simulation of the iron partial density of phonon states enables the identification of three FeN4 species in our catalyst, one of them comprising a sixfold coordination with end‐on bonded oxygen as one of the axial ligands

    Certainty ranges facilitated explicit and transparent judgments regarding evidence credibility

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    Objectives: The Grading of Recommendations Assessment, Development and Evaluation approach to rating certainty of evidence includes five domains of reasons for rating down certainty. Only one of these, precision, is easily amenable through the confidence interval to quantitation. The other four (risk of bias, inconsistency, indirectness, and publication bias) are not. Nevertheless, conceptually, one could consider a quantified "certainty range" within which the true effect lies. The certainty range would be at least as wide as the confidence interval and would expand with each additional reason for uncertainty. Study Design and Setting: We have applied this concept to rating the certainty of evidence in the baseline risk of venous thromboembolism (VTE) and bleeding in patients undergoing urological surgery. We considered rating up moderate or low quality evidence when the net benefit of VTE prophylaxis was unequivocally positive, that is, when the smallest plausible value of VTE reduction was greater than the largest plausible value of increased bleeding. To establish whether the net benefit was unequivocally positive, we expanded the range of plausible values by 20% for each of the four nonquantitative domains in which there were serious limitations. Results: We present how we applied these methods to examples of open radical cystectomy and laparoscopic partial nephrectomy. In high-VTE risk laparoscopic partial nephrectomy patients and high-and medium-VTE risk open radical cystectomy patients, results proved robust to expanded certainty intervals, justifying rating up quality of evidence. In low -risk patients, the results were not robust, and rating up was therefore not appropriate. Conclusion: This work represents the first empirical application in a decision -making context of the previously suggested concept of certainty ranges and should stimulate further exploration of the associated theoretical and practical issues. (C) 2018 Elsevier Inc. All rights reserved.Peer reviewe

    Developing clinical practice guidelines: target audiences, identifying topics for guidelines, guideline group composition and functioning and conflicts of interest

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    Clinical practice guidelines are one of the foundations of efforts to improve health care. In 1999, we authored a paper about methods to develop guidelines. Since it was published, the methods of guideline development have progressed both in terms of methods and necessary procedures and the context for guideline development has changed with the emergence of guideline clearing houses and large scale guideline production organisations (such as the UK National Institute for Health and Clinical Excellence). It therefore seems timely to, in a series of three articles, update and extend our earlier paper. In this first paper we discuss: the target audience(s) for guidelines and their use of guidelines; identifying topics for guidelines; guideline group composition (including consumer involvement) and the processes by which guideline groups function and the important procedural issue of managing conflicts of interest in guideline development

    Interpreting the results of patient reported outcome measures in clinical trials: The clinician's perspective

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    This article deals with the problem of interpreting health-related quality of life (HRQL) outcomes in clinical trials. First, we will briefly describe how dichotomization and item response theory can facilitate interpretation. Based on examples from the medical literature for the interpretation of HRQL scores we will show that dichotomies may help clinicians understand information provided by HRQL instruments in RCTs. They can choose thresholds to calculate proportions of patients benefiting based on absolute scores or change scores. For example, clinicians interpreting clinical trial results could consider the difference in the proportion of patients who achieve a mean score of 50 before and after an intervention on a scale from 1 to 100. For the change score approach, they could consider the proportion of patients who have changed by a score of 5 or more. Finally, they can calculate the proportion of patients benefiting and transform these numbers into a number needed to treat or natural frequencies. Second, we will describe in more detail an approach to the interpretation of HRQL scores based on the minimal important difference (MID) and proportions. The MID is the smallest difference in score in the outcome of interest that informed patients or informed proxies perceive as important, either beneficial or harmful, and that would lead the patient or clinician to consider a change in the management. Any change in management will depend on the downsides, including cost and inconvenience, associated with the intervention. Investigators can help with the interpretation of HRQL scores by determining the MID of an HRQL instrument and provide mean differences in relation to the MID. For instance, for an MID of 0.5 on a seven point scale investigators could provide the mean change on the instrument as well as the proportion of patients with scores greater than the MID. Thus, there are several steps investigators can take to facilitate this process to help bringing HRQL information closer to the bedside

    Internal consistency reliability is a poor predictor of responsiveness

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    BACKGROUND: Whether responsiveness represents a measurement property of health-related quality of life (HRQL) instruments that is distinct from reliability and validity is an issue of debate. We addressed the claims of a recent study, which suggested that investigators could rely on internal consistency to reflect instrument responsiveness. METHODS: 516 patients with chronic obstructive pulmonary disease or knee injury participating in four longitudinal studies completed generic and disease-specific HRQL questionnaires before and after an intervention that impacted on HRQL. We used Pearson correlation coefficients and linear regression to assess the relationship between internal consistency reliability (expressed as Cronbach's alpha), instrument type (generic and disease-specific) and responsiveness (expressed as the standardised response mean, SRM). RESULTS: Mean Cronbach's alpha was 0.83 (SD 0.08) and mean SRM was 0.59 (SD 0.33). The correlation between Cronbach's alpha and SRMs was 0.10 (95% CI -0.12 to 0.32) across all studies. Cronbach's alpha alone did not explain variability in SRMs (p = 0.59, r(2 )= 0.01) whereas the type of instrument was a strong predictor of the SRM (p = 0.012, r(2 )= 0.37). In multivariable models applied to individual studies Cronbach's alpha consistently failed to predict SRMs (regression coefficients between -0.45 and 1.58, p-values between 0.15 and 0.98) whereas the type of instrument did predict SRMs (regression coefficients between -0.25 to -0.59, p-values between <0.01 and 0.05). CONCLUSION: Investigators must look to data other than internal consistency reliability to select a responsive instrument for use as an outcome in clinical trials

    A Decision Aid for COPD patients considering inhaled steroid therapy: development and before and after pilot testing

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    <p>Abstract</p> <p>Background</p> <p>Decision aids (DA) are tools designed to help patients make specific and deliberative choices among disease management options. DAs can improve the quality of decision-making and reduce decisional conflict. An area not covered by a DA is the decision of a patient with chronic obstructive pulmonary disease (COPD) to use inhaled steroids which requires balancing the benefits and downsides of therapy.</p> <p>Methods</p> <p>We developed a DA for COPD patients considering inhaled steroid therapy using the Ottawa Decision Support Framework, the best available evidence for using inhaled steroid in COPD and the expected utility model. The development process involved patients, pulmonologists, DA developers and decision making experts. We pilot tested the DA with 8 COPD patients who completed an evaluation questionnaire, a knowledge scale, and a validated decisional conflict scale.</p> <p>Results</p> <p>The DA is a computer-based interactive tool incorporating four different decision making models. In the first part, the DA provides information about COPD as a disease, the different treatment options, and the benefits and downsides of using inhaled steroids. In the second part, it coaches the patient in the decision making process through clarifying values and preferences. Patients evaluated 10 out of 13 items of the DA positively and showed significant improvement on both the knowledge scale (p = 0.008) and the decisional conflict scale (p = 0.008).</p> <p>Conclusion</p> <p>We have developed a computer-based interactive DA for COPD patients considering inhaled steroids serving as a model for other DAs in COPD, in particular related to inhaled therapies. Future research should assess the DA effectiveness.</p

    Self-administration and standardisation of the chronic respiratory questionnaire: a randomised trial in three German-speaking countries

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    AbstractThe chronic respiratory questionnaire (CRQ) has demonstrated excellent measurement properties in patients with chronic obstructive pulmonary disease (COPD), but in its original form it is limited by the requirement for interviewer-administration and the individualised dyspnoea questions. The objective of this randomised trial was to examine the evaluative properties of the interviewer and self-administered German CRQ as well as of a standardised CRQ dyspnoea domain. In a multinational trial we randomly allocated 71 patients with COPD to complete the interviewer administered CRQ (CRQ-IA) or the self-administered CRQ (CRQ-SA) and other validation measures at the beginning and end of a respiratory rehabilitation program. We assessed and compared responsiveness and longitudinal validity of the CRQ. The change scores of all CRQ domains were above the minimal clinically important difference of 0.5. Responsiveness of the fatigue domain was higher for the CRQ-SA compared to CRQ-IA (P=0.02), but there was no difference in responsiveness on the other domains. Compared to the standardised dyspnoea domain the individualised dyspnoea questions tended to show greater responsiveness for both the CRQ-IA (P=0.07) and CRQ-SA (P=0.10). We found better longitudinal validity for the CRQ-SA represented by larger correlations between CRQ change scores and those of other validation instruments. Taken these results into consideration, researchers in COPD, in particular those in German-language countries can utilise any one of four CRQ formats that have proved both valid and responsive
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