Return of fear after retrospective inferences about the absence of an unconditioned stimulus during extinction

We examined whether the effect of an extinction phase can be influenced retrospectively by information about the cause of the absence of the unconditioned stimulus (US) during that phase. Participants were subjected to a differential fear conditioning procedure, followed by an extinction procedure. Afterwards, half of the participants were presented with information about a technical failure, which explained why the US had been absent during the extinction phase. The other participants received information that was unrelated to the US. During a subsequent presentation of the target conditioned stimulus (CS), only the former group of participants showed renewed anticipatory skin conductance responding and a return of US expectancy. The results are in accordance with a propositional account of associative learning and highlight the importance of retrospective reasoning as a cause of relapse after exposure therapy

An analysis of the decision-making process for single implant treatment in general practice

Background: There is little information on the decision-making process for single implant treatment in general practice. Aim: To study the incidence of and the factors associated with the decision to perform single implant treatment after tooth extraction by general practitioners in a private, fee-for-service setting. Methods: One hundred practitioners with a general dental practice in Ghent were randomly selected from an official list received by the Belgian Social Security Institute. Clinicians were asked to fill in a study form for every single extraction they performed during an 8-week period. The study form related to the treatment decision as discussed with the patient and a number of patient- and clinician-related factors. The association of these factors with single implant treatment was evaluated using univariate tests and logistic regression. A decision-tree was also constructed with the predictors from the regression analysis as independent variables. Results: Ninety-four general dentists (52 males, 42 females; mean age 49; range 24–68)agreed to participate and extracted 1180 single teeth in an equal number of patients (50% males, 50% females; mean age 53; range 18–90). The main reasons for tooth loss were caries (48%) and periodontal disease (28%). At the time of extraction tooth replacement was deemed necessary in half of the patients and are movable partial denture was chosen in 55% of them. Similar frequencies were found for fixed partial denture (23%) and single implant treatment (21%). Although the vast majority of patient- and clinician-related factors showed a significant association with the latter on the basis of univariate tests, logistic regression only identified seven predictors. These included location of the extracted tooth, number of missing teeth, regular supportive care, bone loss at adjacent teeth, restoration level of adjacent teeth, gender of the clinician and dentists’ experience in implant prosthetics. The decision tree identified bone loss at adjacent teeth and number of missing teeth as the most important predictors for single implant treatment. Conclusions and clinical implications: If tooth replacement was deemed necessary at the time of extraction, a single implant was the treatment of choice in only one-fifth of the patients. Mainly oral factors had an impact on the decision-making process in contrast to patients’ background and medical factors. Dentists’ experience in implant prosthetics also showed a positive association with single implant treatment as opposed to dentists’ experience in implant surgery

Fear expression and return of fear following threat instruction with or without direct contingency experience

Prior research showed that mere instructions about the contingency between a conditioned stimulus (CS) and an unconditioned stimulus (US) can generate fear reactions to the CS. Little is known, however, about the extent to which actual CS US contingency experience adds anything beyond the effect of contingency instructions. Our results extend previous studies on this topic in that it included fear potentiated startle as an additional dependent variable and examined return of fear (ROF) following reinstatement. We observed that CS US pairings can enhance fear reactions beyond the effect of contingency instructions. Moreover, for all measures of fear, instructions elicited immediate fear reactions that could not be completely overridden by subsequent situational safety information. Finally, ROF following reinstatement for instructed CS+s was unaffected by actual experience. In summary, our results demonstrate the power of contingency instructions and reveal the additional impact of actual experience of CS US pairings

Oral health-related quality of life changes after placement of immediately loaded single implants in healed alveolar ridges or extraction sockets : a 5-year prospective follow-up study

Objectives: The impact of single implants on oral health-related quality of life (OHRQoL) is scarcely investigated, especially when combined with immediate placement and loading in extraction sockets. The aim was to describe prospectively the changes of OHRQoL with single implants placed in the esthetic zone in healed ridges or in extraction sockets after 5 years. Material and Methods: Ninety-six patients, enrolled at three clinical centers, received 102 single implants placed in a healed ridge (n = 54 implants/50 patients) or in extraction sockets (n = 48 implants/46 patients). Implants were immediately provisionalized, and permanent crowns were cemented after 12 weeks. Oral health impact profile questionnaires (OHIP-14) were completed before surgery, after 1 (provisional crown), 6 (permanent crown), 12 and 60 months, respectively. The overall OHIP-14 score pertains to seven domains with two items each and was assessed on a Likert scale of 0–4 (0 = never and 4 = very often). The evolution of the total OHIP-14 score and changes within all OHIP domains over time and between groups were assessed with a linear mixed-effect model analysis. Results: After 5 years, overall implant survival was 98%. The total OHIP-14 score for both groups combined decreased from 0.50 at baseline to 0.17 at 6 months (P < 0.001), indicative of improvement. For both groups, this remained stable up to 5 years (P = 0.41). However, after 5 years, the total OHIP-14 score revealed a statistically significantly higher improvement in the healed group compared with the extraction group (P = 0.027). Conclusion: Missing a single tooth in the maxillary esthetic zone leads to limited OHRQoL problems as reflected by a low overall OHIP score. However, OHRQoL improves less in the extraction group, reflecting that replacing a missing tooth is perceived as more beneficial than replacing a present tooth

Misconceptions of Upper-Secondary School Students on Doing Behavioral Sciences Research

With its long tradition, research on misconceptions helps to understand how concepts are learned and how learning in the disciplines can be supported. Up to now, research on misconceptions has focused on natural sciences, while research on misconceptions in behavioral sciences is scarce, not to say absent. In this study an attempt was made to reveal upper secondary school students’ misconceptions on doing research in behavioral sciences. The starting point for the study were research proposals of upper secondary school students. As part of a larger study, students were asked to write a research proposal in maximum two pages. A two-steps approach was adopted in the analysis of these research proposals. First, using a codebook containing both deductive and inductive codes, two-pagers were analyzed in order to identify ‘errors’. In a second step, an interpretative analysis aimed at inferring potential misconceptions underlying these errors. The study can be considered as a starting point for research on misconceptions in behavioral sciences which is currently missing in the field

Prediction of effective genome size in metagenomic samples

We introduce a novel computational approach to predict effective genome size (EGS; a measure that includes multiple plasmid copies, inserted sequences, and associated phages and viruses) from short sequencing reads of environmental genomics (or metagenomics) projects. We observe considerable EGS differences between environments and link this with ecologic complexity as well as species composition (for instance, the presence of eukaryotes). For example, we estimate EGS in a complex, organism-dense farm soil sample at about 6.3 megabases (Mb) whereas that of the bacteria therein is only 4.7 Mb; for bacteria in a nutrient-poor, organism-sparse ocean surface water sample, EGS is as low as 1.6 Mb. The method also permits evaluation of completion status and assembly bias in single-genome sequencing projects

Lower extremity near-infrared spectroscopy after popliteal block for orthopaedic foot surgery

BACKGROUND: Noninvasive measurement of cutaneous tissue oxygenation using near-infrared spectroscopy (NIRS) has become common in peri-operative care. Following institution of peripheral nerve blocks, neurovascular alterations in the blocked region have been described. OBJECTIVE: The primary aim of this study encompassed the assessment of the influence of a popliteal block on changes in regional oxygen saturation (SrO(2)), and the location of most prominent changes. METHOD: We conducted a prospective randomised controlled trial. Hundred twenty patients who received a popliteal block for foot surgery were included. Popliteal block was performed under echographic guidance. The patients were randomized in 3 groups according to the location of the SrO(2) electrodes on the legs. Bilateral SrO(2) measurements were performed simultaneously. SrO(2) in the operated leg and in the control leg was measured at baseline and 1, 5, 10, 15, and 30 minutes after the perineural injection. We quantified the evolution in SrO(2) by calculating over time the differences in SrO(2) values between the operated and control leg (=ΔSrO(2)). RESULTS: At 30 minutes, ΔSrO(2) increased significantly (p<0.05) at the plantar side of the foot (11.3% ± 2.9%), above the ankle (4.9% ± 1.3%) and the popliteal fossa (3.6% ± 1.2%). CONCLUSION: At 30 minutes after institution of the popliteal block, ΔSrO(2) was most prominent at the plantar side of the foot as compared with measurement performed above the ankle or under the knee