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Interactions between an oblique shock wave generated by a sharp fin placed on a cylindrical surface and the incoming boundary layer are investigated to unravel the mean features of the resulting shock/boundary layer interaction (SBLI) unit. This fin-on-cylinder SBLI unit has several unique features caused by the three-dimensional (3-D) relief offered by the cylindrical surface that noticeably alter the shock structure. Complementary experimental and computational studies are made to delineate both the surface and off-body flow features of the fin-on-cylinder SBLI unit and to obtain a detailed understanding of the mechanisms that dictate the mean flow and wall pressure features of the SBLI unit. Results show that the fin-on-cylinder SBLI exhibits substantial deviation from quasi-conical symmetry that is observed in planar fin SBLI. Furthermore, the separated flow growth rate appears to decrease with downstream distance and the separation size is consistently smaller than the planar fin SBLI with the same inflow and fin configurations. The causes for the observed diminution of the separated flow and its downstream growth rate were investigated in the light of changes caused by the cylinder curvature on the inviscid as well as separation shock. It was found that the inviscid shock gets progressively weakened in the region close to the triple point with downstream distance due to the 3-D relief effect from cylinder curvature. This weakening of the inviscid shock feeds into the separation shock, which is also independently impacted by the 3-D relief, to result in the observed modifications in the fin-on-cylinder SBLI unit.
Recent findings highlight that there are prenatal risks for affective disorders that are mediated by glucocorticoid mechanisms, and may be specific to females. There is also evidence of sex differences in prenatal programming mechanisms and developmental psychopathology, whereby effects are in opposite directions in males and females. As birth weight is a risk for affective disorders, we sought to investigate whether maternal prenatal cortisol may have sex-specific effects on fetal growth. Participants were 241 mothers selected from the Wirral Child Health and Development Study (WCHADS) cohort (n=1233) using a psychosocial risk stratifier, so that responses could be weighted back to the general population. Mothers provided saliva samples, which were assayed for cortisol, at home over 2 days at 32 weeks gestation (on waking, 30-min post-waking and during the evening). Measures of infant birth weight (corrected for gestational age) were taken from hospital records. General population estimates of associations between variables were obtained using inverse probability weights. Maternal log of the area under the curve cortisol predicted infant birth weight in a sex-dependent manner (interaction term P=0.029). There was a positive and statistically significant association between prenatal cortisol in males, and a negative association in females that was not statistically significant. A sex interaction in the same direction was evident when using the waking (P=0.015), and 30-min post-waking (P=0.013) cortisol, but not the evening measure. There was no interaction between prenatal cortisol and sex to predict gestational age. Our findings add to an emerging literature that suggests that there may be sex-specific mechanisms that underpin fetal programming.
CVD accounted for 27 % of all deaths in the UK in 2014, and was responsible for 1·7 million hospital admissions in 2013/2014. This condition becomes increasingly prevalent with age, affecting 34·1 and 29·8 % of males and females over 75 years of age respectively in 2011. The dysregulation of cholesterol metabolism with age, often observed as a rise in LDL-cholesterol, has been associated with the pathogenesis of CVD. To compound this problem, it is estimated by 2050, 22 % of the world's population will be over 60 years of age, in culmination with a growing resistance and intolerance to pre-existing cholesterol regulating drugs such as statins. Therefore, it is apparent research into additional therapies for hypercholesterolaemia and CVD prevention is a growing necessity. However, it is also imperative to recognise this complex biological system cannot be studied using a reductionist approach; rather its biological uniqueness necessitates a more integrated methodology, such as that offered by systems biology. In this review, we firstly discuss cholesterol metabolism and how it is affected by diet and the ageing process. Next, we describe therapeutic strategies for hypercholesterolaemia, and finally how the systems biology paradigm can be utilised to investigate how ageing interacts with complex systems such as cholesterol metabolism. We conclude by emphasising the need for nutritionists to work in parallel with the systems biology community, to develop novel approaches to studying cholesterol metabolism and its interaction with ageing.
The polarisation observations of the central region (containing the jet) of the galaxy M87 were obtained in May 1980, with the polarimeter (Visvanathan 1972) attached to the f/15 cassegrain focus of the AAT. The IPCS was used in direct mode to record the images of the field. Figure 1 shows a single, raw image of M87 in the light of B (the image shown is 90 arcsec square). The knots referred to in the text are marked. One complete observation consists of 12 images of the object field, corresponding to the 12 selected position angles of the polaroid filter, rotated from 0° to 330° in 30° increments. The Taurus software (Taylor and Atherton 1980) was used to increment the data to the relevant memory location. The data were stored on tape after a sufficient number of complete rotations of the polaroid were completed.
Mothers' self-reported stroking of their infants over the first weeks of life modifies the association between prenatal depression and physiological and emotional reactivity at 7 months, consistent with animal studies of the effects of tactile stimulation. We now investigate whether the effects of maternal stroking persist to 2.5 years. Given animal and human evidence for sex differences in the effects of prenatal stress we compare associations in boys and girls.
From a general population sample of 1233 first-time mothers recruited at 20 weeks gestation we drew a random sample of 316 for assessment at 32 weeks, stratified by reported inter-partner psychological abuse, a risk indicator for child development. Of these mothers, 243 reported at 5 and 9 weeks how often they stroked their infants, and completed the Child Behavior Checklist (CBCL) at 2.5 years post-delivery.
There was a significant interaction between prenatal anxiety and maternal stroking in the prediction of CBCL internalizing (p = 0.001) and anxious/depressed scores (p < 0.001). The effects were stronger in females than males, and the three-way interaction prenatal anxiety × maternal stroking × sex of infant was significant for internalizing symptoms (p = 0.003). The interactions arose from an association between prenatal anxiety and internalizing symptoms only in the presence of low maternal stroking.
The findings are consistent with stable epigenetic effects, many sex specific, reported in animal studies. While epigenetic mechanisms may be underlying the associations, it remains to be established whether stroking affects gene expression in humans.
The current banking crisis has reminded us of how risks materialising in one part of the financial system can have a widespread impact, affecting other financial markets and institutions and the broader economy. This paper, prepared on behalf of the Actuarial Profession, examines how such events have an impact on the entire financial system and explores whether such disturbances may arise within the insurance and pensions sectors as well as within banking. The paper seeks to provide an overview of a number of banking and other financial crises which have occurred in the past, illustrated by four case studies. It discusses what constitutes a systemic event and what distinguishes it from a large aggregate system wide shock. Finally, it discusses how policy-makers can respond to the risk of such systemic financial failures.
To describe an unusual case of lateral neck swelling in a patient with a permanent cardiac pacemaker.
We describe a patient who presented with a painful, lateral neck swelling due to an internal jugular vein thrombus. This thrombus originated from around pacemaker wires in the subclavian vein. This case is unusual, as the vast majority of thromboses in patients with cardiac pacemakers are found in the subclavian vein alone. We also review the literature on the relationship between cardiac pacemakers and internal jugular vein thrombosis, and on the management of the latter.
Our patient illustrates a rare cause of a painful, lateral neck swelling: an internal jugular vein thrombus secondary to a cardiac pacemaker. Clinicians should be wary of such pathology in similar patients, in order to ensure early treatment and avoidance of complications.
Data from a representative community sample were used to explore predictors of lifetime suicidality and to examine associations between distal adolescent and more proximal adult risks.
Data are from a midlife follow-up of the Isle of Wight study, an epidemiological sample of adolescents assessed in 1968. Ratings of psychiatric symptoms and disorder, relationships and family functioning and adversity were made in adolescence; adult assessments included lifetime psychiatric history and suicidality, neuroticism and retrospective reports of childhood sexual abuse and harsh parenting.
A wide range of measures of childhood psychopathology, adverse experiences and interpersonal difficulties were associated with adult suicidality; associations were particularly strong for adolescent irritability, worry and depression. In multivariate analyses, substantial proportions of these effects could be explained by their association with adult psychopathology and neuroticism, but additional effects remained for adolescent irritability and worry.
Factors of importance for long-term suicidality risk are evident in adolescence. These include family and experiential adversities as well as psychopathology. In particular, markers of adolescent worry and irritability appeared both potent risks and ones with additional effects beyond associations with adult disorder and adult neuroticism.
The effects of anabolic steroids on the quality of voice have been well documented; however, no study has established significant structural changes in the larynx as a direct result of anabolic steroid use. We report a unique case of a 47-year-old male smoker and professional body builder who presented with progressive stridor and hoarseness following abuse of anabolic steroids over a period of two years. Conservative management failed to resolve his symptoms and a planned tracheostomy was performed to secure his airway. Subsequently he was treated with multiple laser resections and eventually decannulated. No case of severe laryngitis in association with anabolic steroid usage has been reported previously in the literature.
We present a case report of a patient who developed a sinonasal myopericytoma treated by surgical excision through a lateral rhinotomy. Some aggressive features on pre-operative computed tomography scanning and the complexity of recent changes in the histological nomenclature for these tumours led to consideration of adjuvant therapy. The close histological relationship between myopericytoma, myofibromatosis, solitary myofibroma and infantile haemangiopericytoma is discussed. This group of lesions constitute a single morphological spectrum with differentiation towards perivascular myoid cells (pericytes). Currently myopericytoma is the most appropriate and accepted term embracing all these entities. A review of the literature has been reassuring in identifying these tumours as benign but with a reasonably high rate of local recurrence (17 per cent). The treatment of choice is surgical excision with further excisions for local recurrence.
Recent stellar spectral libraries have sought higher resolution and the accurate determination of specific optical spectral indeces as stellar population indicators. But the value of accurate flux comparisons over wide wavelength regions should still be emphasized, particularly as more and better spectro-photometric data for composite populations becomes available.
We present the second case of primary synchronous bilateral tonsillar squamous cell carcinoma reported in the English literature and evaluate the role of fluoro-deoxyglucose positron emission tomography scanning in the search for the occult primary tumour in a patient presenting with metastatic nodal disease in the head and neck.
The dielectric properties of goethite and, in particular, the changes during the topotactic conversion of goethite to hematite were studied from room temperature to about 800 °C in the frequency range of 400 to 3000 MHz using the cavity perturbation technique. The complex permittivity, that is, both the real and the imaginary or absorptive parts (έ and ἕ), were measured under various heating regimens. In addition, thermogravimetric analysis (TGA) was performed to characterize the transformation of goethite to hematite. The Debye relaxation formalism was applied to the processes occurring both during and after the main dehydroxylation reaction to calculate the relaxation times. The Arrhenius equation for thermally activated relaxation times was used to determine the activation energies. Both the real and the absorptive parts of the permittivity exhibited a significant peak during the main part of the goethite to hematite decomposition reaction. Above the transformation, there was another, less dramatic, thermally activated increase in the permittivity values. The increase in the permittivities during the goethite to hematite transformation was attributed to the formation of quasi-free migrating radicals, for example, hydroxyl ions, oxygen ions, or hydrogen atoms, during the dehydroxylation of goethite. The derivative thermogravimetric analysis (DTGA) curve was found to be directly related to the transient values of the real and the imaginary permittivities. Higher heating rates resulted in an accelerated rate of dehydroxylation and therefore higher values of the transient permittivities. In the temperature range of 400 °C to 500 °C (i.e., just above the dehydroxylation peak), the real permittivity exhibited a varying frequency dependence, which suggested that changes were occurring in the newly formed, highly defected hematite structure, which is referred to as hydrohematite. During the reaction there were multiple relaxation processes and thus the Debye relationship could not be applied. However, at temperatures above about 500 °C, the structure stabilized, the Debye relationship was more closely followed, and the relaxation times could be determined as a function of temperature. The activation energy for the relaxation process above 500 °C was determined to be 0.47 kJ/mol.
Background. How insight, paranoia and depression evolve in relation to each other during and after the first episode of schizophrenia is poorly understood but of clinical importance.
Method. Serial assessments over 18 months were made using multiple instruments in a consecutive sample of 257 patients with first episode DSM-IV non-affective psychosis. Repeated measures of paranoia, insight, depression and self-esteem were analysed using structural equation modelling, to examine the direction of relationships over time after controlling for confounds.
Results. Depression was predicted directly by greater insight, particularly at baseline, and by greater paranoia at every stage of follow-up. Neither relationship was mediated by self-esteem, although there was a weak association of lower self-esteem with greater depression and better insight. Paranoia was not strongly associated with insight. Duration of untreated psychosis and substance use at baseline predicted depression at 18 months.
Conclusions. In first-episode psychosis, good insight predicts depression. Subsequently, paranoia is the strongest predictor. Neither effect is mediated by low self-esteem. Effective treatment of positive symptoms is important in preventing and treating low mood in early schizophrenia.
In this report we characterize associations between parental psychiatric disorders and children's psychiatric symptoms and disorders using a population-based sample of 850 twin families. Juvenile twins are aged 8–17 years and are personally interviewed about their current history of DSM-III-R conduct, depression, oppositional-defiant, overanxious, and separation anxiety disorders using the CAPA-C. Mothers and fathers of twins are personally interviewed about their lifetime history of DSM-III-R alcoholism, antisocial personality disorder, generalized anxiety disorder, major depression, panic disorder/agoraphobia, social phobia, and simple phobia using a modified version of the SCID and the DIS. Generalized least squares and logistic regression are used to identify the juvenile symptoms and disorders that are significantly associated with parental psychiatric histories. The specificity of these associations is subsequently explored in a subset of families with maternal plus parental psychiatric histories with a prevalence > 1 %. Parental depression that is not comorbid or associated with a different spousal disorder is associated with a significantly elevated level of depression and overanxious disorder symptoms and a significantly increased risk for overanxious disorder. Risks are higher for both symptomatic domains in association with maternal than paternal depression, and highest in association with maternal plus paternal depression. Risks for other juvenile symptoms and disorders index the comorbid and spousal histories with which parental depression is commonly associated. Paternal alcoholism that is not comorbid or associated with a maternal disorder is not significantly associated with current psychiatric symptoms or disorders in offspring. Risks for oppositional-defiant or conduct symptoms/disorders in the offspring of alcoholic parents index parental comorbidity and/or other spousal histories.
To date there are only two recorded cases of patients with coexistent pleomorphic adenoma and myotonic dystrophy in the literature. We present two further cases, describe the general features of myotonic dystrophy and discuss the theory of a direct association between these two conditions.
Background. There is substantial evidence that the genetic liability to autism confers a risk for a
range of more subtle social and communication impairments, as well as stereotyped and repetitive
behaviours. Recent research suggests that increased expression of particular personality traits may
be a manifestation of the liability to autism.
Methods. To investigate this we examined the personality traits of the adult relatives of 99 autistic
and 36 Down's syndrome probands, using the informant version of the Modified Personality
Results. There was significantly increased expression of the traits anxious, impulsive, aloof, shy,
over-sensitive, irritable and eccentric among the autism relatives with evidence of different profiles
for male and female relatives and for parents and adult children. Factor analysis revealed three
broad groups of traits, two of which (‘withdrawn’ and ‘difficult’) appeared to reflect impairments
in social functioning and a third group of anxiety related traits (‘tense’). Each of these factors
differed in their pattern of associations with the factor we termed ‘withdrawn’ showing a similar
pattern of association to that found for other autism related conditions. The ‘tense’ factor appeared
in part to be related to the burden of caring for an autistic child.
Conclusions. This study confirms the finding that particular personality traits may aggregate in the
family members of autistic individuals and furthermore that some of these traits may be a
manifestation of the liability to autism.
Background. There is extensive evidence of statistical associations between family
discord/maladaptation and antisocial behaviour in the children, but questions remain on the extent to
which the psychopathological risks are genetically or environmentally mediated.
Methods. Twin pairs (N = 1350), aged 8 to 16 years, in the general population-based Virginia Twin
Study of Adolescent Behavioral Development were assessed using the Child and Adolescent
Psychiatric Assessment interview administered separately to both twins and both parents.
Structured interviews for parental lifetime psychiatric disorders were also administered to the
mothers and fathers. Maternal reports on Olsson's Family Adaptability and Cohesiveness
questionnaire and the Dyadic Adjustment Scale were used as indices of the family environment. A
path analytical model based on an extended twin-family design was used to test hypotheses about
parent–offspring similarity for conduct disorder symptomatology.
Results. Family discord and maladaptation, which intercorrelated at 0·63, were associated with a
roughly two-fold increase in risk for conduct disorder symptomatology. When parental conduct
disorder was included in the model the environmental mediation effect for family maladaptation
remained, but that for family discord was lost.
Conclusion. It is concluded that there is true environmental mediation from family maladaptation,
operating as a shared effect, which accounts for 3·5% of the phenotypic variance. The assumptions
underlying this genetic research strategy are made explicit, together with its strengths and
Background. Previous studies on assortment for psychiatric
disorders have reported discrepant
findings. We aimed to test whether there is a significant association for
including alcoholism, generalized anxiety disorder, major depressive disorder,
panic disorder and
phobias between husbands and wives in two population-based samples. We
whether marital resemblance occurs primarily within or across psychiatric
disorders and if
assortment for psychopathology is primary or secondary to assortment for
Methods. A model for mate selection addressed whether the correlation
between mates for
psychiatric disorders arises from direct assortment (primary homogamy)
or through correlation
with other variables for which assortment occurs (secondary homogamy) or
assortment. The model accounted for within-person co-morbidity as well
as across-spouse data.
Results. Findings suggested that a moderate degree of assortment
exists both within and across
psychiatric diagnoses. Only a small amount of the observed marital resemblance
for mental illness
could be explained by assortment for correlated variables such as age,
religious attendance and
education. Similar results were obtained for the two samples separately
and confirmed in their joint
analysis, revealing that the co-morbidity and assortment findings, except
for the marital correlation
for age, religious attendance and education, replicate across samples.
Conclusions. Significant but moderate primary assortment exists
for psychiatric disorders. The bias
in twin studies that have ignored the small amount of assortment is negligible.
Background. Previous twin studies of hyperactivity have
supported a ‘contrast effect’, whereby the
more hyperactive the rating of one twin, the less the rating of the other.
It has not been clear whether
contrast effects occur in the twins' behaviour or in the ratings
made of their behaviour but the
implications for hyperactivity are different under the two models.
Method. We use hyperactivity ratings from mothers and teachers
for 1644 twin pairs in the Virginia
Twin Study of Adolescent Behavioral Development (VTSABD) to explore the
origin of contrast
effects, making use of independent teacher reports in a proportion
of twins. Models were fitted
separately for the two informants and jointly to ratings combined through
a latent variable, using structural equation modelling.
Results. Models for maternal data confirm the contrast effect
previously reported. Teacher ratings
show a different form of bias, with both twin confusion and correlated
alternative but not mutually exclusive explanations of the data.
Latent variable modelling of the
joint responses allowed comparison of a model in which the contrast
effect was placed on maternal
ratings, representing bias, versus one in which the contrast occurred
in the underlying ‘true’
phenotype. The fit of the former model was significantly better.
Conclusions. Support is provided for the notion of
contrast effects as a form of rater bias in maternal
hyperactivity ratings. Different bias in teacher reports highlight that
no one report can be
considered a gold standard. The extent to which such biases may
distort information for other data
sources such as sib-pair studies of concordance/discordance is discussed.