2,277 research outputs found

    The influence of alcohol (0.5‰) on the control and manoeuvring level of driving behaviour, finding measures to assess driving impairment:A simulator study

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    Objective: The influence of psychoactive substances on driving performance and traffic safety has been extensively studied. Research on the influence of alcohol at the control level of behaviour (i.e. automated processes) has been well established and has shown that the ability to operate a vehicle decreases with rising alcohol levels. However, results one level higher at the manoeuvring level (i.e. conscious processes), are inconsistent. The current study aimed to replicate findings on the influence of alcohol on the control level of behaviour and investigate effects on the manoeuvring level in order to find suitable measures to assess driving impairment. Method: The study was double-blind, placebo-controlled with a counterbalanced treatment order and a two-way crossover design. Thirty participants performed tasks in a driving simulator under the influence of alcohol (0.5‰) and a placebo. In the driving tasks the control level of behaviour (swerving, average speed, and speed variation) was investigated, as well as the manoeuvring level of behaviour (distance to other traffic during an overtaking manoeuvre, reaction time to a traffic light turning amber, and response to a suddenly merging car). Results: As expected, alcohol affected the control level of behaviour negatively. Participants swerved more and showed more speed variation after alcohol intake. The manoeuvring level of driving behaviour was also affected by alcohol. The distance to other drivers during an overtaking manoeuvre was smaller under the influence of alcohol. Results on reaction time were however less straightforward. Reaction time increased significantly under the influence of alcohol when reacting to a traffic light but not in reaction to a car unexpectedly merging into traffic. When analysing behaviour in reaction to these different events in more detail it became clear that they were responded to in varying manners, making it difficult to find an average impairment measure. Conclusions: The deteriorating effect of alcohol at the control level of driving behaviour was replicated, confirming the suitability of the standard deviation of lateral position and the variation in speed as measures of impairment. At the manoeuvring level, the kept distance to the leading car during an overtaking manoeuvre appeared to be a suitable measure to assess impairment as well as reaction time to a traffic light. The current study also confirms the difficulties in evaluating complex driving behaviour and the need for more research on this subject

    GMC Collisions as Triggers of Star Formation. III. Density and Magnetically Regulated Star Formation

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    We study giant molecular cloud (GMC) collisions and their ability to trigger star cluster formation. We further develop our three dimensional magnetized, turbulent, colliding GMC simulations by implementing star formation sub-grid models. Two such models are explored: (1) Density-Regulated, i.e., fixed efficiency per free-fall time above a set density threshold; (2) Magnetically- Regulated, i.e., fixed efficiency per free-fall time in regions that are magnetically supercritical. Variations of parameters associated with these models are also explored. In the non-colliding simulations, the overall level of star formation is sensitive to model parameter choices that relate to effective density thresholds. In the GMC collision simulations, the final star formation rates and efficiencies are relatively independent of these parameters. Between non-colliding and colliding cases, we compare the morphologies of the resulting star clusters, properties of star-forming gas, time evolution of the star formation rate (SFR), spatial clustering of the stars, and resulting kinematics of the stars in comparison to the natal gas. We find that typical collisions, by creating larger amounts of dense gas, trigger earlier and enhanced star formation, resulting in 10 times higher SFRs and efficiencies. The star clusters formed from GMC collisions show greater spatial sub-structure and more disturbed kinematics

    Effects of methylphenidate on executive functioning in children and adolescents with ADHD after long-term use:a randomized, placebo-controlled discontinuation study

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    BACKGROUND: Methylphenidate may improve executive functioning in children with attention-deficit/hyperactivity disorder (ADHD). However, it is unclear if there are still acute effects of methylphenidate on executive functioning after long-term use. METHODS: In a randomized double-blind, placebo-controlled discontinuation study, 94 children and adolescents (ages 8-18 years) who used methylphenidate beyond two years were either assigned to seven weeks of continued treatment with 36 or 54 mg of extended-release methylphenidate or to gradual withdrawal over three weeks to placebo for four weeks. Performance on neuropsychological tasks, measuring working memory, response inhibition, attentional flexibility and psychomotor speed was compared between both groups using mixed models for repeated measures. Additionally, we investigated within the discontinuation group if a deterioration on the investigator-rated Clinical Global Impressions Improvement scale after withdrawing to placebo was related to a worse performance on the neuropsychological tasks. This study was registered in the Netherlands Trial Register (www. Trialregister.nl) with identifier 5252. RESULTS: After withdrawal of methylphenidate, the discontinuation group made more errors on working memory (β = -1.62, SD = 0.56, t = -2.88, p = .01, Cohen's f2 = .14), independent from reaction time compared to baseline, in contrast to the continuation group. We did not find differences in changes in response inhibition, attentional flexibility and psychomotor speed between the two groups. Also, there were no significant differences in task measures between the participants who deteriorated clinically and those who did not. CONCLUSIONS: Our study shows that methylphenidate has a beneficial effect on working memory after two years of use. Future studies should explore whether cognitive outcomes may aid clinical decision-making on the continued use of methylphenidate, given dissociation between cognitive and behavioural effects of stimulant medication

    Continued Benefits of Methylphenidate in ADHD After 2 Years in Clinical Practice:A Randomized Placebo-Controlled Discontinuation Study

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    Objective: The benefits of long-term use of methylphenidate treatment in children and adolescents with attention deficit hyperactivity disorder (ADHD), as frequently prescribed in clinical practice, are unclear. The authors investigated whether methylphenidate remains beneficial after 2 years of use. Methods: Ninety-four children and adolescents (ages 8-18 years) who had been treated in regular care with methylphenidate for more than 2 years were randomly assigned to double-blind continuation of treatment for 7 weeks (36 or 54 mg/day of extended-release methylphenidate) or gradual withdrawal over 3 weeks, to 4 weeks of placebo. The primary outcome measure was the investigator-rated ADHD Rating Scale (ADHD-RS); secondary outcome measures were the investigator-rated Clinical Global Impressions improvement scale (CGI-I) and the Conners' Teacher Rating Scale-Revised: Short Form (CTRS-R:S). Continuous ratings were analyzed with mixed model for repeated measures analyses, and the CGI-I with a chi-square test. Results: The mean ADHD-RS scores at baseline for the continuation and discontinuation groups, respectively, were 21.4 (SD=9.7) and 19.6 (SD=8.9); after 7 weeks, the mean scores were 21.9 (SD=10.8) and 24.7 (SD=11.4), with a significant between-group difference in change over time of 24.6 (95% CI=28.7, 20.56) in favor of the group that continued methylphenidate treatment. The ADHD-RS inattention subscale and the CTRS-R: S ADHD index and hyperactivity subscale also deteriorated significantly more in the discontinuation group. The CGI-I indicated worsening in 40.4% of the discontinuation group, compared with 15.9% of the continuation group. Conclusions: Continued treatment with methylphenidate remains effective after long-term use. Some individual patients may, however, be withdrawn from methylphenidate without deterioration. This finding supports guideline recommendations that patients be assessed periodically to determine whether there is a continued need for methylphenidate treatment

    Effects of Discontinuing Methylphenidate on Strengths and Difficulties, Quality of Life and Parenting Stress

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    Objectives: To study the effects of discontinuation of long-term methylphenidate use on secondary outcome measures of strengths and difficulties, quality of life (QoL), and parenting stress. Methods: Ninety-four children and adolescents aged 8 to 18 years who had used methylphenidate for over 2 years were randomly assigned to double-blind continuation of treatment for 7 weeks (36 or 54 mg extended release methylphenidate) or to gradual withdrawal over 3 to 4 weeks placebo. We used mixed models for repeated measures to investigate effects on parent, teacher, and child ratings of hyperactivity/inattention and comorbid symptoms with the Strengths and Difficulties Questionnaire (SDQ), investigator- and teacher-rated oppositional symptoms (Conners Teacher Rating Scale-Revised: short form [CTRS-R:S]), and parent-rated aggression with the Retrospective Modified Overt Aggression Scale. QoL was assessed with the Revised Questionnaire for Children and Adolescents to record health-related quality of life and parenting stress with the Nijmegen Parental Stress Index. Results: Hyperactivity/inattention scores from the parent- and teacher-rated SDQ (difference in mean change over time of respectively: -1.1 [95% confidence interval, CI, -2.0 to -0.3]; p = 0.01; -2.9 [95% CI -2.9 to -0.7; p = 0.01]) and oppositional scores of the teacher-rated CTRS-R:S (difference in mean change -1.9 95% CI [-3.1 to -0.6; p <0.01]) deteriorated to a significantly larger extent in the discontinuation group than in the continuation group. We did not find effects on other symptom domains, aggression, QoL, and parenting stress after discontinuation of methylphenidate. Conclusion: Our study suggests beneficial effects of long-term methylphenidate use beyond 2 years for oppositional behaviors in the school environment. Similarly, beneficial effects were found on hyperactivity-inattention symptoms as rated by parent and teacher scales, confirming our primary study on investigator ratings of attention-deficit/hyperactivity disorder. However, discontinuation of methylphenidate did not appear to have impact on other comorbid problems or aspects of the child's or parental functioning

    Temporary diverting stoma in therapy-refractory luminal colonic Crohn's disease:an alternative to immediate colorectal resection?

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    AimCreation of a diverting stoma in patients with Crohn's disease (CD) can counteract luminal inflammation. The clinical utility of a diverting stoma with the prospect of restoration of gastrointestinal continuity warrants further investigation. The aim of this work was to evaluate the long-term effects of creation of a diverting stoma on the disease course in patients with luminal colonic CD.MethodIn this retrospective, multicentre cohort study we investigated the disease course of patients who received a diverting stoma in the biological era. Clinical characteristics, medication use and surgical course were assessed at the time of creation of the diverting stoma and during follow-up. The primary outcome was the rate of successful and lasting reestablishment of gastrointestinal continuity.ResultsThirty six patients with refractory luminal CD from four institutions underwent creation of a diverting stoma. Of the overall cohort, 20 (56%) patients had their gastrointestinal continuity reestablished after initial stoma creation and 14 (39%) who had their stoma reversed remained stoma-free during a median of 3.3 years follow-up (interquartile range 2.1–6.1 years). Absence of stoma reversal was associated with the presence of proctitis (p = 0.02). Colorectal resection after creation of a diverting stoma was performed in 28 (78%) patients, with 7 (19%) having a less extensive resection and 6 (17%) having a more extensive resection compared with the surgical plan before stoma creation.ConclusionA diverting stoma could potentially be an alternative to immediate definitive stoma placement in specific populations consisting of patients with luminal colonic CD, especially in the absence of proctitis

    Взаимовлияние валютного курса и платежного баланса в Украине

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    Цель статьи - выявить основные каналы взаимовлияния валютного курса и платежного баланса для определения наиболее подходящей модели валютного регулирования в Украине

    Predictors of allergen sensitization in Singapore children from birth to 3 years

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    10.1186/s13223-016-0161-xAllergy, asthma, and clinical immunology : official journal of the Canadian Society of Allergy and Clinical Immunology121Article number 56GUSTO (Growing up towards Healthy Outcomes
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