320 research outputs found

    An empirical assessment of stimulus presentation mode bias in conjoint analysis

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    Conjoint analysis, which aims to uncover the optimal combination of attributes influencing customer choice, is widely used by marketers to predict the success of new product and service introductions. In recent years, researchers have incorporated considerable mathematical sophistication into conjoint models and extended its domain to diverse areas such as pricing, market share, profitability, product positioning, distribution channels, and advertising. Despite these advances, the predictive power of conjoint applications is often compromised by response biases and measurement errors. The purpose of this research is to isolate and investigate the impact of one such bias that arises from the manner in which stimuli are presented to respondents. Based upon an appraisal of over four decades of conjoint studies in the major marketing journals, the authors make a case for the possible existence of two types of biases, i.e.: (1) stimulus joint presentation bias, when concept cards are shown simultaneously (side by side) to respondents, and (2) stimulus separate presentation bias, where cards are presented separately (one at a time). Two conjoint experiments were designed to investigate the effects of these biases on respondent choices. Results indicate that bias manifests itself in conjoint designs when there is a mismatch between presentation mode and respondents’ cognitive (evaluable) burden. Left unaddressed, stimulus presentation mode bias may: (1) have a deleterious effect on respondents’ choice behavior; and (2) compromize the predictive accuracy of conjoint models. The authors discuss several approaches that can account for and mitigate the negative impact of presentation mode biases on conjoint outcomes

    Trends in levels of self-reported psychological distress among individuals who seek psychiatric services over eight years: a comparison between age groups in three population surveys in Stockholm County

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    BACKGROUND: Psychiatric service use has increased in Sweden and in other developed countries, particularly among young people. Possible explanations include lower threshold for help-seeking among young people, but evidence is scarce. METHODS: We analysed the 2002, 2006 and 2010 Stockholm public health surveys for changes in the mean level of psychological distress among adult users of psychiatric in- and outpatient services in four age groups: 18-24, 25-44, 45-64 and ≥65 years. Psychological distress was measured via the 12-item General Health Questionnaire (GHQ-12), using the Likert scoring method 0-1-2-3. In- and out-patient psychiatric service use within 6 months from the surveys was obtained from registers. RESULTS: The mean level of distress among young adults 18-24 years who utilize psychiatric services decreased between 2002 (mean GHQ-12 score, 95% confidence interval 20.5, 18.1-23.0) and 2010 (16.2, 14.6-17.7), while it remained fairly stable in older age groups. Results were similar in sex-stratified analyses, although the decrease was statistically significant only among young women 18-24 years. At the end of the follow-up, the level of distress among patients was similar for all age-groups. CONCLUSIONS: There were no differences between age groups in the level of distress when seeking care at the end of the follow-up period, supporting that there is no age-specific over- or under-consumption of psychiatric care in later years. However, the lowered threshold for help-seeking among young adults over time might have contributed to increases in psychiatric service use in the young age group. Public health policy and service delivery planning should consider the needs of the widening group of young users of psychiatric services

    MP-1 Cysticercosis in Goats in the Semi-arid Tropics of Timor Island, East Nusa Tenggara, Indonesia

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    Semi-arid region of West Timor has a good potential of livestock farming, including goat farming. Small scale goat farms in West Timor raise their animals in semi-intensive system by rearing their animals in pasture or rice field. There are a high demand of goat in the local market especially prior to Kurban Fiest. Despite high population growth of goat, there are some reasons causing low productivity, such as parasite infections. Taeniid cestodes infect carnivores (as well as human) as the definitive host and involve a wide range of intermediate host where they present as metacestode cyst.1Cysticercosis or infection of cestode larval stages (metacestode) may appear vary from subclinical to severe clinical signs.1 Cysticercus infection lead to productivity losses2 even mortality in livestock.3 They are responsible for economic losses due to partial or total condemnation of carcass and offal.1, 3 Cysticercosis also pose a risk of public health.3 The zoonosis risk even higher in developing countries and especially in rural area, people lives in close proximity with animals,  poor sanitation3 and low awareness. Dogs and wild canids are common definitive host of the most metacestodes occurring in goat and other ruminants.1 But some of them involve human as definitive host as well as incidental intermediate host in their life cycle.4 To make an effective control of cestode infection, it is necessary to identify the agent and collect its epidemiological data. This research aims to determine the prevalence and to identify the etiological agent of cysticercosis of goats in semi-arid region of West Timor.Cysticercosis in Goats in the Semi-arid Tropics of Timor Island, East Nusa Tenggara, Indonesi

    TElmisartan in the management of abDominal aortic aneurYsm (TEDY): The study protocol for a randomized controlled trial

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    Background: Experimental studies suggest that angiotensin II plays a central role in the pathogenesis of abdominal aortic aneurysm. This trial aims to evaluate the efficacy of the angiotensin receptor blocker telmisartan in limiting the progression of abdominal aortic aneurysm. Methods/Design: Telmisartan in the management of abdominal aortic aneurysm (TEDY) is a multicentre, parallel-design, randomised, double-blind, placebo-controlled trial with an intention-to-treat analysis. We aim to randomly assign 300 participants with small abdominal aortic aneurysm to either 40 mg of telmisartan or identical placebo and follow patients over 2 years. The primary endpoint will be abdominal aortic aneurysm growth as measured by 1) maximum infra-renal aortic volume on computed tomographic angiography, 2) maximum orthogonal diameter on computed tomographic angiography, and 3) maximum diameter on ultrasound. Secondary endpoints include change in resting brachial blood pressure, abdominal aortic aneurysm biomarker profile and health-related quality of life. TEDY is an international collaboration conducted from major vascular centres in Australia, the United States and the Netherlands. Discussion: Currently, no medication has been convincingly demonstrated to limit abdominal aortic aneurysm progression. TEDY will examine the potential of a promising treatment strategy for patients with small abdominal aortic aneurysms. Trial registration: Australian and Leiden study centres: Australian New Zealand Clinical Trials Registry ACTRN12611000931976, registered on 30 August 2011; Stanford study centre: clinicaltrials.gov NCT01683084, registered on 5 September 2012

    Implications of Advancing Paternal Age: Does It Affect Offspring School Performance?

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    Average paternal age is increasing in many high income countries, but the implications of this demographic shift for child health and welfare are poorly understood. There is equivocal evidence that children of older fathers are at increased risk of neurodevelopmental disorders and reduced IQ. We therefore report here on the relationship between paternal age and a composite indicator of scholastic achievement during adolescence, i.e. compulsory school leaving grades, among recent birth cohorts in Stockholm County where delayed paternity is notably common. We performed a record-linkage study comprising all individuals in Stockholm County who finished 9 years of compulsory school from 2000 through 2007 (n = 155,875). Data on school leaving grades and parental characteristics were retrieved from administrative and health service registers and analyzed using multiple linear regression. Advancing paternal age at birth was not associated with a decrease in school leaving grades in adolescent offspring. After adjustment for year of graduation, maternal age and parental education, country of birth and parental mental health service use, offspring of fathers aged 50 years or older had on average 0.3 (95% CI −3.8, 4.4) points higher grades than those of fathers aged 30–34 years. In conclusion, advancing paternal age is not associated with poorer school performance in adolescence. Adverse effects of delayed paternity on offspring cognitive function, if any, may be counterbalanced by other potential advantages for children born to older fathers

    Association between preeclampsia and attention deficit hyperactivity disorder: a population-based and sibling-matched cohort study

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    Objective: Examine the association between preeclampsia and attention deficit hyperactivity disorder (ADHD), using a large Swedish‐based registry cohort. Methods: This study comprised 2,047,619 children, with 114,934 (5.6%) cases of ADHD. Preeclampsia was based on two alternate definitions: 1. Preeclampsia (using ICD‐9/ICD‐10) 2.Preeclampsia and small for gestational age (SGA) combined. ADHD was determined in one of two ways: 1. If a diagnosis of ADHD was present in the National Patient Register or 2.If an individual was in receipt of ADHD medication in the Prescribed Drug Register. Multivariate Cox proportional hazards regression analysis allowed adjustment for several perinatal/sociodemographic factors. Sibling‐matched analysis further controlled for shared genetic and familial confounding. Results: In the adjusted Cox model, preeclampsia was associated with an increase in likelihood of ADHD (HR: 1.15, 95% CI: 1.12, 1.19). The HR for preeclampsia and those born SGA was 1.43 (95% CI: 1.31, 1.55) in the adjusted model, compared to those unexposed to preeclampsia/SGA. The sibling‐matched analysis did not materially change these associations (HR: 1.13, 95% CI: 1.05, 1.22) and 1.55 (95% CI: 1.28, 1.88). Conclusions: Exposure to preeclampsia or preeclampsia/SGA was associated with ADHD, independent of genetic/familial factors shared by siblings. However, it is important to note that sibling‐matched analysis can only adjust for factors that are constant between pregnancies, therefore residual confounding cannot be ruled out. Further research is needed to explore modifiable risk factors and identify those most‐at‐risk babies following delivery

    Association between preeclampsia and autism spectrum disorder: a population-based study

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    Background: The environmental contribution of autism spectrum disorder (ASD) is approximately 17%–50%, highlighting the importance of investigating factors potentially contributing to the likelihood of its development, and of gaining a greater understanding of the pathogenesis surrounding ASD. The objective of this study was to examine the association between preeclampsia and ASD using a population‐based cohort study. Methods: All singleton live births in Sweden from 1982 to 2010 were included, using data from Swedish National Registers. Exposures of interest included: (a) preeclampsia (classified according to ICD‐8, ICD‐9 and ICD‐10) and (b) preeclampsia and small for gestational age (SGA) combined, used as a proxy for preeclampsia with placental dysfunction. ASD status was based on ICD‐9 and ICD‐10. The cohort consisted of 2,842,230 children, with 54,071 cases of ASD. Follow‐up began from the child's first birthday, and data were censored at first diagnosis of ASD, death, migration or end of study period (31st December 2016). We conducted multivariate Cox proportional hazards regression analysis, adjusting for several perinatal and sociodemographic factors, selected a priori. We further controlled for shared genetic and familial confounding using sibling‐matched analysis. Results: In the adjusted Cox proportional hazards regression analysis, preeclampsia was associated with a 25% increase in the likelihood of ASD (Hazard Ratio (HR): 1.25, 95% CI:1.19, 1.30) compared with those unexposed to preeclampsia, while in the sibling‐matched analysis the HR was 1.17 (95% CI: 1.06, 1.28). The HR for preeclampsia and SGA combined was 1.66 (95% CI: 1.49, 1.85) in the adjusted Cox model and 1.95 (95% CI: 1.53, 2.48) in the sibling‐matched analysis. Conclusions: Exposure to preeclampsia or preeclampsia/SGA (i.e. SGA baby exposed to preeclampsia) was associated with ASD. The stronger association with preeclampsia/SGA than preeclampsia alone suggests that placental pathology may be a mechanism for the increased likelihood of ASD

    The association between preeclampsia and childhood development and behavioural outcomes

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    Objectives: To examine the associations between preeclampsia and longitudinal child developmental and behavioural outcomes using data from a nationally representative study of children living in Ireland. Methods: We used maternal-reported data from the Growing Up in Ireland longitudinal study of children. Data on preeclampsia and preeclampsia + small for gestational age (SGA) were collected when children were 9-months old. Data on child development and behavioural outcomes were collected at 9-months using the Ages and Stages Questionnaire (ASQ), and at 3 years, 5 years and 7–8 years using the Strengths and Difficulties Questionnaire (SDQ). Multivariate logistic regression analysis was used to examine the association between preeclampsia exposure and failure of ASQ domains, and abnormal SDQ domains. Linear spline multilevel models were used to examine the association between preeclampsia and preeclampsia + SGA and repeated measures of SDQ. All models controlled for several perinatal and sociodemographic factors. Results: A total of 10,692 children were included in the study at baseline, representing a weighted total of 70,791. Multivariate logistic regression suggested that preeclampsia was not associated with failing any ASQ domain. Preeclampsia was associated with abnormal SDQ cut-off of emotional (≥ 5) and hyperactivity (≥ 7) domains at age 5 years only. In the linear spline model, mean SDQ score was higher at each time point in exposed groups. Conclusions for Practice: While we did not find strong evidence of associations between preeclampsia and child developmental and behavioural outcomes overall, some associations between preeclampsia-exposure and subtle behavioural issues did persist. Further research is needed to replicate these findings, and determine the clinical significance of changes in SDQ scores
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