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For outbreaks of gastrointestinal disease, rapid identification of the source is crucial to enable public health intervention and prevent further cases. Outbreak investigation comprises analyses of exposure information from cases and, if required, undertaking analytical epidemiological studies. Hypothesis generation has been reliant on empirical knowledge of exposures historically associated with a given pathogen. Epidemiology studies are resource-intensive and prone to bias, one of the reasons being the difficulties in recruiting appropriate controls. For this paper, the information from cases was compared against pre-defined background exposure information. As exemplars, three past outbreaks were used, one of common and two of rare exposures. Information from historical case trawling questionnaires was used to define background exposure having removed any exposures implicated with the outbreak. The case-background approach showed good sensitivity and specificity, identifying correctly all outbreak-related exposures. One additional exposure related to a retailer was identified and four food items where all cases had been exposed. In conclusion, the case-background method, a development of the case-case design, can be used to assist with hypothesis generation or when a case-control study may not be possible to carry out.
In recent years, the discovery of massive quasars at
has provided a striking challenge to our understanding of the origin and growth of supermassive black holes in the early Universe. Mounting observational and theoretical evidence indicates the viability of massive seeds, formed by the collapse of supermassive stars, as a progenitor model for such early, massive accreting black holes. Although considerable progress has been made in our theoretical understanding, many questions remain regarding how (and how often) such objects may form, how they live and die, and how next generation observatories may yield new insight into the origin of these primordial titans. This review focusses on our present understanding of this remarkable formation scenario, based on the discussions held at the Monash Prato Centre from November 20 to 24, 2017, during the workshop ‘Titans of the Early Universe: The Origin of the First Supermassive Black Holes’.
Mitochondrial dysfunction and resulting changes in adiposity have been observed in the offspring of animals fed a high fat (HF) diet. As iron is an important component of the mitochondria, we have studied the offspring of female rats fed complete (Con) or iron-deficient (FeD) rations for the duration of gestation to test for similar effects. The FeD offspring were ~12% smaller at weaning and remained so because of a persistent reduction in lean tissue mass. The offspring were fed a complete (stock) diet until 52 weeks of age after which some animals from each litter were fed a HF diet for a further 12 weeks. The HF diet increased body fat when compared with animals fed the stock diet, however, prenatal iron deficiency did not change the ratio of fat:lean in either the stock or HF diet groups. The HF diet caused triglyceride to accumulate in the liver, however, there was no effect of prenatal iron deficiency. The activity of the mitochondrial electron transport complexes was similar in all groups including those challenged with a HF diet. HF feeding increased the number of copies of mitochondrial DNA and the prevalence of the D-loop mutation, however, neither parameter was affected by prenatal iron deficiency. This study shows that the effects of prenatal iron deficiency differ from other models in that there is no persistent effect on hepatic mitochondria in aged animals exposed to an increased metabolic load.
Background: The evidence regarding whether co-morbid obsessive compulsive personality disorder (OCPD) is associated with treatment outcomes in obsessive compulsive disorder (OCD) is mixed, with some research indicating that OCPD is associated with poorer response, and some showing that it is associated with improved response. Aims: We sought to explore the role of OCPD diagnosis and the personality domain of conscientiousness on treatment outcomes for exposure and response prevention for OCD. Method: The impact of co-morbid OCPD and conscientiousness on treatment outcomes was examined in a clinical sample of 46 participants with OCD. Results: OCPD diagnosis and scores on conscientiousness were not associated with poorer post-treatment OCD severity, as indexed by Yale-Brown Obsessive Compulsive Scale (YBOCS) scores, although the relative sample size of OCPD was small and thus generalizability is limited. Conclusion: This study found no evidence that OCPD or conscientiousness were associated with treatment outcomes for OCD. Further research with larger clinical samples is required.
Perfectionism is a risk and maintaining factor across psychopathology and has been proposed to be a transdiagnostic process. The aim of this study was to examine the reliability and validity of the Clinical Perfectionism Questionnaire (CPQ) in 32 adults (75% female, M age = 35.54 years, SD = 9.71) with a range of psychological disorders, presenting for treatment of clinical perfectionism. There was evidence that the CPQ was correlated with established measures of perfectionism and theoretically related constructs including self-criticism and dichotomous thinking. The CPQ was also able to predict treatment outcome. The internal consistency was not adequate in the current study; however, the sample size was small. Future studies should examine the psychometric properties of the CPQ in a larger sample of individuals with a range of psychological disorders.
Using semi-empirical isochrones, we find the age of the Taurus star-forming region to be 3-4 Myr. Comparing the disc fraction in Taurus to young massive clusters suggests discs survive longer in this low density environment. We also present a method of photometrically de-reddening young stars using iZJH data.
Background: Improving mental health literacy in the general population is important as it is associated with early detection and treatment-seeking for mental health problems. Target areas for mental health literacy programs should be guided by research that tests the impact of improving knowledge of psychological constructs associated with the development of mental health problems. Aims: This study investigated the impact of providing corrective information about the nature of intrusive thoughts on their subsequent appraisal in a community sample. Method: In an online, experimental design, 148 community participants completed measures of obsessive-compulsive symptoms and appraisals (Obsessive Compulsive Inventory-Revised [OCI-R]; Intrusions Inventory [III]). Individuals were instructed to read either a brief informational text about the nature of intrusive thoughts or a control text. All participants then completed post-test measurements of appraisals. Intervention effectiveness was analysed using hierarchical multiple regression. Results: Individuals in the intervention group reported significantly lower levels of maladaptive appraisals than those in the control group (α = .05). Conclusions: The results of this study support the efficacy of provision of brief written information in reducing negative appraisals of intrusive thoughts in a community sample. It suggests a possible role for education about intrusive thoughts as a prevention strategy for obsessive-compulsive disorder.
Depressive symptoms are prominent psychopathological features of Huntington's disease (HD), making a negative impact on social functioning and well-being.
We compared the frequencies of a history of depression, previous suicide attempts and current subthreshold depression between 61 early-stage HD participants and 40 matched controls. The HD group was then split based on the overall HD group's median Hospital Anxiety and Depression Scale-depression score into a group of 30 non-depressed participants (mean 0.8, s.d. = 0.7) and a group of 31 participants with subthreshold depressive symptoms (mean 7.3, s.d. = 3.5) to explore the neuroanatomy underlying subthreshold depressive symptoms in HD using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI).
Frequencies of history of depression, previous suicide attempts or current subthreshold depressive symptoms were higher in HD than in controls. The severity of current depressive symptoms was also higher in HD, but not associated with the severity of HD motor signs or disease burden. Compared with the non-depressed HD group DTI revealed lower fractional anisotropy (FA) values in the frontal cortex, anterior cingulate cortex, insula and cerebellum of the HD group with subthreshold depressive symptoms. In contrast, VBM measures were similar in both HD groups. A history of depression, the severity of HD motor signs or disease burden did not correlate with FA values of these regions.
Current subthreshold depressive symptoms in early HD are associated with microstructural changes – without concomitant brain volume loss – in brain regions known to be involved in major depressive disorder, but not those typically associated with HD pathology.
This editorial proposes a shift in emphasis in the field of mental health epidemiology in conflict-affected settings. After a brief summary of the nature of contemporary armed conflicts, we consider the current and potential roles that epidemiology can play with regard to: (1) establishing the burden of mental disorders; (2) identifying risk and protective factors; and (3) intervention research. We advocate for improved methodological rigor; more attention to mixed methods approaches and multi-level longitudinal research; inclusion of the determinants of mental health beyond conflict-related violence; and consideration of a wider array of mental health outcomes. We particularly highlight the importance of expanding interest to epidemiological research that advances prevention and promotion interventions (e.g., in the early childhood period), in order to fill the gap between epidemiology and mental health practice in conflict-affected settings.
Background: Clinical perfectionism is a transdiagnostic process that has been found to maintain eating disorders, anxiety disorders and depression. Cognitive behavioural models explaining the maintenance of clinical perfectionism emphasize the contribution of dichotomous thinking and resetting standards higher following both success and failure in meeting their goals. There has been a paucity of research examining the predictions of the models and motivation to change perfectionism. Motivation to change is important as individuals with clinical perfectionism often report many perceived benefits of their perfectionism; they are, therefore, likely to be ambivalent regarding changing perfectionism. Aims: The aim was to compare qualitative responses regarding questions about motivation to change standards and cognitions regarding failure to meet a personal standard in two contrasting groups with high and low negative perfectionism. Negative perfectionism refers to concern over not meeting personal standards. Method: A clinical group with a range of axis 1 diagnoses who were elevated on negative perfectionism were compared to a group of athletes who were low on negative perfectionism. Results: Results indicated that the clinical group perceived many negative consequences of their perfectionism. They also, however, reported numerous benefits and the majority stated that they would prefer not to change their perfectionism. The clinical group also reported dichotomous thinking and preferring to either keep standards the same or reset standards higher following failure, whilst the athlete group reported they would keep standards the same or set them lower. Conclusions: The findings support predictions of the cognitive behavioural model of clinical perfectionism.
Background: Magical thinking has been proposed to have an aetiological role in obsessive compulsive disorder (OCD). Aims: To address the limitations of existing measures of magical thinking we developed and validated a new 24-item measure of magical thinking, the Illusory Beliefs Inventory (IBI). Method: The validation sample comprised a total of 1194 individuals across two samples recruited via an Internet based survey. Results: Factor analysis identified three subscales representing domains relevant to the construct of magical thinking: Magical Beliefs, Spirituality, and Internal State and Thought Action Fusion. The scale had excellent internal consistency and evidence of convergent and discriminant validity. Evidence of criterion-related concurrent validity confirmed that magical thinking is a cognitive domain associated with OCD and is largely relevant to neutralizing, obsessing and hoarding symptoms. Conclusions: It is important for future studies to extend the evidence of the psychometric properties of the IBI in new populations and to conduct longitudinal studies to examine the aetiological role of magical thinking.
Perfectionism has been suggested as a risk factor for the development of stress and burnout in psychotherapists, but this has not been extensively investigated. This study examined the relationship between perfectionism, stress and burnout in 87 Australian clinical psychologists. Stress had significant influences on the relationship between perfectionism and burnout. Specifically, stress was found to be a partial intervening variable in the relationship between perfectionism and personal burnout. In addition, stress was also found to completely mediate the influence of perfectionism on work-related and client-related burnout. The results indicated that perfectionism was both directly and indirectly related through stress to various types of burnout in clinical psychologists. Implications of the findings for research in to the utility of intervention for high levels of perfectionism in clinical psychologists are discussed.
This theoretical study examines confined viscous planar jet/wake flows with continuous velocity profiles. These flows are characterized by the shear, confinement, Reynolds number and shear-layer thickness. The primary aim of this paper is to determine the effect of confinement on viscous jets and wakes and to compare these results with corresponding inviscid results. The secondary aim is to consider the effect of viscosity and shear-layer thickness. A spatio-temporal analysis is performed in order to determine absolute/convective instability criteria. This analysis is carried out numerically by solving the Orr–Sommerfeld equation using a Chebyshev collocation method. Results are produced over a large range of parameter space, including both co-flow and counter-flow domains and confinements corresponding to 0.1 < h2/h1 < 10, where the subscripts 1 and 2 refer to the inner and outer streams, respectively. The Reynolds number, which is defined using the channel width, takes values between 10 and 1000. Different velocity profiles are used so that the shear layers occupy between 1/2 and 1/24 of the channel width. Results indicate that confinement has a destabilizing effect on both inviscid and viscous flows. Viscosity is found always to be stabilizing, although its effect can safely be neglected above Re = 1000. Thick shear layers are found to have a stabilizing effect on the flow, but infinitely thin shear layers are not the most unstable; having shear layers of a small, but finite, thickness gives rise to the strongest instability.
In this theoretical study, a linear spatio-temporal analysis is performed on unconfined and confined inviscid jet/wake flows with surface tension in order to determine convective/absolute instability criteria. There is a single mode that is due to surface tension and many modes that are due to the jet/wake column. In the unconfined case, the full impulse response is considered in the entire outer flow. On the one hand, the surface tension mode propagates slowly in the cross-stream direction but dominates at the front and back of the wavepacket. On the other hand, the jet/wake column modes propagate more quickly in the cross-stream direction and therefore define the boundaries of the central region of the wavepacket. The flow is particularly unstable when these modes interact. For unconfined flows, it is found that at low and intermediate surface tensions the flow can be more absolutely unstable than that without surface tension but at high surface tensions the flow is stabilized. The effect of confinement has previously been studied but not with the inclusion of surface tension. Confinement and surface tension combined cause the transition from convective to absolute instability to occur even with significant coflow. This effect is examined over an infinite domain of density ratios and confinement.
Although there has been a long interest in the personality traits associated with obsessive-compulsive disorder (OCD), few studies have examined differences on normal, dimensional personality traits for individuals with OCD compared with other clinical disorders. The purpose of this study was to replicate and extend upon the work of Rector et al. (2002) who found unique associations between OCD and trait domains and facets of the five-factor model of personality (FFM) when compared with a clinical sample of depressed individuals. The current study compared individuals with a current diagnosis of OCD (n=21) with individuals with a current diagnosis of anxiety or depression but no OCD symptoms (n=39) on the Revised NEO Personality Inventory (NEO PI-R Form S). Of particular interest was whether individuals with OCD would differ from other clinically anxious/depressed individuals on the actions facet of the FFM, as this facet is known to be related to harm and risk avoidance, and previous research suggests specific relationships between these forms of avoidance and OCD. Individuals with OCD were found to have lower scores on the actions, competence and self-discipline facets. These results add further support to previous research that suggests unique associations between trait domains and facets of the FFM and OCD.
A multi-technique approach was used to map the spatial distribution of seabed biotopes (i.e. physical habitats and their associated benthic assemblages) in the vicinity of Hastings Shingle Bank in the eastern English Channel, part of which is licensed for the extraction of marine aggregates for the construction industry. An area of seabed, approximately 12×4 km in size, was surveyed using a high-resolution sidescan sonar system, and a mosaic of the output was produced, covering 100% of the survey area. The area was then divided into acoustically distinct regions based on the sidescan sonar data, and the benthic communities and sediment types within each of the regions were ground-truthed using a Hamon grab fitted with a video camera, and using a heavy duty 2-m beam trawl. Additional information concerning the seabed was obtained through the application of video and photographic techniques. Sediments within the survey area ranged from cobbles and coarse gravels on the Shingle Bank, to various grades of sands to the north and south. Analysis of faunal data revealed the presence of statistically distinct biological assemblages within each acoustic region. Using all available data, four discrete biotopes were identified and their spatial distribution mapped across the survey area.
Background and objective: To investigate the clinical application of a mathematical model of pulmonary gas exchange, which ascribes hypoxaemia to shunt and ventilation/perfusion mismatch. Ventilation/perfusion mismatch is quantified by ΔPO2, which is the drop in oxygen pressure from alveoli to lung capillaries. Shunt and ΔPO2 were used to describe changes in oxygenation after coronary artery bypass grafting.
Methods: Fourteen patients were studied 2–4 h after surgery and on postoperative days 2, 3 and 7. On each occasion inspired oxygen fraction was changed in four to six steps to obtain arterial oxygen saturation (SaO2) in the range of 90–100%, enabling construction of FeO2/SaO2 curves. Measurements of ventilation, circulation and oxygenation were entered in a previously described mathematical model of pulmonary gas exchange.
Results: We found that oxygenation was most impaired 3 days after surgery. By fitting the mathematical model to the FeO2/SaO2 curve, we found that shunt remained constant throughout the study period. However, ΔPO2 increased from 0.5 kPa (median, range 0–3.8) 2–4 h after surgery, to 3.2 kPa (range 1.2–6.4, P < 0.05) on day 2, and to 4.0 kPa (range 1.2–8.3) on day 3. On day 7, ΔPO2 decreased to 2.2 kPa (range 0–3.5, P < 0.05).
Conclusions: Ventilation/perfusion mismatch (ΔPO2), rather than shunt, explains the changes in postoperative oxygenation. The model of pulmonary gas exchange may serve as a useful and potentially non-invasive clinical tool for monitoring patients at risk of postoperative hypoxaemia.