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We analysed both structural and functional aspects of sentences containing the four adverbials “after”, “before”, “because”, and “if” in two dense corpora of parent-child interactions from two British English-acquiring children (2;00–4;07). In comparing mothers’ and children's usage we separate out the effects of frequency, cognitive complexity and pragmatics in explaining the course of acquisition of adverbial sentences. We also compare these usage patterns to stimuli used in a range of experimental studies and show how differences may account for some of the difficulties that children have shown in experiments. In addition, we report descriptive data on various aspects of adverbial sentences that have not yet been studied as a resource for future investigations.
Suicide risk is increased in patients with a history of psychiatric hospitalization.
Aim
To explore how suicide risk varies by age during psychiatric hospitalization and in the year post-discharge.
Methods
This is a population-based case-control study of all suicides (n = 20,675; 70% male) in Sweden aged ≥18 years during 1991–2003. Each suicide was individually matched to 10 population controls by age, sex, and county of residence. Discharge diagnoses of a mental disorder (except dementia and other organic disorders) in the year prior to suicide were identified by register linkage. Odds ratios (OR) were calculated by conditional logistic regression to estimate the relative risk of suicide in those with psychiatric diagnoses compared to the general population. ORs were estimated by age group (18–34 years, 35–49 years, 50–64 years, and ≥ 65 years) and timing of the suicide in relation to discharge.
Results
During hospitalization, the youngest age group had the greatest suicide risk elevation [OR 64 (95% CI 44-92)]. In the first month post-discharge, the oldest age group had the highest suicide risk elevation [OR 162 (95% 66–399) in the first week and OR 127 (95% 67–242) in the second to fourth weeks]. In the remaining eleven months, suicide risk elevation was lower and relatively similar in different age groups.
Conclusions
During the year following psychiatric hospitalization, an especially high attention should be paid to the suicide risk of the elderly patients in the first month post-discharge.
Patients with schizophrenia are at increased risk of suicide, but data from controlled studies of how pharmacotherapy is related to suicide risk is limited.
Aim
To explore suicide risk in relation to prescription of antipsychotics and antidepressants.
Methods
Of all patients with a first clinical discharge diagnosis of schizophrenia or schizoaffective disorder in Stockholm County between 1984 and 2000 (n = 4,000), patients who died by suicide within five years from diagnosis were defined as cases (n = 84; 54% male). Individual matching was performed with schizophrenia controls from the same population. Information on prescribed medication was retrieved from psychiatric records in a blinded way. Odds ratios (OR) of the association between medication and suicide risk were calculated by conditional logistic regression.
Results
No significant association was observed between suicide and having ever been prescribed any antidepressant (33 cases and 30 controls) or any antipsychotic (83 cases and 82 controls). A lower suicide risk was found in patients who had ever been prescribed a second generation antipsychotic (risperidone, ziprazidone, olanzapine or clozapine; 12 cases and 23 controls): OR 0.2 (95% confidence interval [CI], 0.1–0.7). When the 6 cases and 8 controls who had been prescribed clozapine were excluded, the OR was 0.1 (95% CI, 0.03–0.6).
Conclusions
The lower suicide risk for patients who had been prescribed second generation antipsychotics may be related to a pharmacological effect of these medications, to differences in compliance, or to differences in other characteristics associated with a lower suicide risk.
Anorexia Nervosa (AN) is a serious psychiatric disorder associated with high mortality.
Aims
To examine mortality patterns in patients with anorexia nervosa and psychiatric comorbidity.
Methods
6009 women who received in-patient treatment for AN between 1973-2003 were followed up retrospectively using Swedish registers. SMR were calculated on the basis of 74 523 person-years for natural causes of death and 80 388 personyears for unnatural causes of death. SMR was calculated for the group as a whole but also for patients with comorbid inpatient-treated psychiatric disorders, defined by respective ICD-codes from the Swedish patient discharge register.
Results
Nearly half of the patients (44.9%) received in-patient treatment for a psychiatric disorder other than AN during the follow-up time. The overall SMR for anorexia nervosa with psychiatric comorbidity was 6.5 (95% CI: 5.2–7.9) for natural causes and 17.6 (95% CI:14.3–21.4) for unnatural causes of death. Comorbid psychiatric disorders yielded very high SMR for unnatural causes of death. The highest SMR for natural causes was estimated for anorexia nervosa with comorbid alcohol use disorder (16.8; 95% CI: 11.7–23.3).
Conclusion
Anorexia nervosa is a disorder with high mortality for natural and unnatural causes of death, especially when psychiatric comorbidity is involved. To correctly diagnose psychiatric comorbidity, particularly alcohol use disorder, and initiate early treatment could be a way to decrease mortality.
Our aim was to identify areas of improvement for current Opioid Maintenance Treatment (OMT) approaches, by analysing European Quality Audit of Opioid Treatment (EQUATOR) data from 8 European countries (Austria, Denmark, France, Germany, Norway, Portugal, Sweden, UK).
Method
A standardised face-to-face survey was administered to OMT patients (OMT-P) and active opioid user (AOU). Reasons for entering and staying out of OMT, rules pertaining to OMT, and factors facilitating OMT retention were compared between countries, and between OMT-P and AOU groups. Both groups were divided into those who never had OMT before [un-experienced OMT-P (n=573) and AOU (n=360)] and those who had been maintained at least once [experienced OMT-P (n=746) and AOU (n=377)].
Results
Motives for starting OMT vary distinctly between countries (p≤0.001). Transnationally, experienced AOU reported concerns about their ability to follow treatment rules and negative treatment experiences as decisive reasons for staying out of OMT. Greater flexibility, less pressure to reduce their treatment dose and greater treatment structure were ranked significantly higher by experienced compared to un-experienced OMT-P as factors that might facilitate treatment retention (p≤0.05).
Conclusion
The major strength of this investigation was the homogenous methodology applied in all countries, which enabled new insights in variations between treatment systems and their impact on patient outcome. Treatment systems need to aim an optimal balance between flexibility and structure. Standardised approaches that still permit tailoring treatment to individual patient needs are crucial to yield maximum benefit for patients, and reduce the considerable societal economic burden of addiction.
In this numerical and theoretical work, we study the turbulent channel flow of Newtonian and elastoviscoplastic fluids. The coherent structures in these flows are identified by means of higher order dynamic mode decomposition (HODMD), applied to a set of data non-equidistant in time, to reveal the role of the near-wall streaks and their breakdown, and the interplay between turbulent dynamics and non-Newtonian effects. HODMD identifies six different high-amplitude modes, which either describe the yielded flow or the yielded–unyielded flow interaction. The structure of the low- and high-frequency modes suggests that the interaction between high- and low-speed streamwise velocity structures is one of the mechanisms triggering the streak breakdown, dominant in Newtonian turbulence where we observe shorter near-wall streaks and a more chaotic dynamics. As the influence of elasticity and plasticity increases, the flow becomes more correlated in the streamwise direction, with long streaks disrupted for short times by localised perturbations, reflected in reduced drag. Finally, we present streamwise-periodic dynamic mode decomposition modes as a viable tool to describe the highly complex turbulent flows, and identify simple well-organised groups of travelling waves.
The Empire of Aksum was one of Africa's most influential ancient civilisations. Traditionally, most archaeological fieldwork has focused on the capital city of Aksum, but recent research at the site of Beta Samati has investigated a contemporaneous trade and religious centre located between Aksum and the Red Sea. The authors outline the discovery of the site and present important finds from the initial excavations, including an early basilica, inscriptions and a gold intaglio ring. From daily life and ritual praxis to international trade, this work illuminates the role of Beta Samati as an administrative centre and its significance within the wider Aksumite world.
The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural–geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.
We study single-phase and particle-laden turbulent channel flows bounded by two incompressible hyper-elastic walls with different deformability at bulk Reynolds number $5600$. The solid volume fraction of finite-size neutrally buoyant rigid spherical particles considered is $10\,\%$. The elastic walls are assumed to be of a neo-Hookean material. A fully Eulerian formulation is employed to model the elastic walls together with a direct-forcing immersed boundary method for the coupling between the fluid and the particles. The data show a significant drag increase and the enhancement of the turbulence activity with growing wall elasticity for both the single-phase and particle-laden flows when compared with the single-phase flow over rigid walls. Drag reduction and turbulence attenuation is obtained, on the other hand, with highly elastic walls when comparing the particle-laden flow with the single-phase flow for the same wall properties; the opposite effect, drag increase, is observed upon adding particles to the flow over less elastic walls. This is explained by investigating the near-wall turbulence, where the strong asymmetry in the magnitude of the wall-normal velocity fluctuations (favouring positive $v^{\prime }$), is found to push the particles towards the channel centre. The particle layer close to the wall contributes to turbulence production by increasing the wall-normal velocity fluctuations, so that in the absence of this layer, smaller wall deformations and in turn turbulence attenuation is observed. For a moderate wall elasticity, we increase the particle volume fraction up to $20\,\%$ and find that particle migration away from the wall is the cause of turbulence attenuation with respect to the flow over rigid walls. However, for this higher volume fractions, the particle induced stress compensates for the decreasing Reynolds shear stress, resulting in a higher overall drag for the case with elastic walls. The effect of the wall elasticity on the overall drag reduces significantly with increasing particle volume fraction.
We present a study of Lagrangian intermittency and its characteristic time scales. Using the concepts of flying and diving residence times above and below a given threshold in the magnitude of turbulence quantities, we infer the time spectra of the Lagrangian temporal fluctuations of dissipation, acceleration and enstrophy by means of a direct numerical simulation in homogeneous and isotropic turbulence. We then relate these time scales, first, to the presence of extreme events in turbulence and, second, to the local flow characteristics. Analyses confirm the existence in turbulent quantities of holes mirroring bursts, both of which are at the core of what constitutes Lagrangian intermittency. It is shown that holes are associated with quiescent laminar regions of the flow. Moreover, Lagrangian holes occur over few Kolmogorov time scales while Lagrangian bursts happen over longer periods scaling with the global decorrelation time scale, hence showing that loss of the history of the turbulence quantities along particle trajectories in turbulence is not continuous. Such a characteristic partially explains why current Lagrangian stochastic models fail at reproducing our results. More generally, the Lagrangian dataset of residence times shown here represents another manner for qualifying the accuracy of models. We also deliver a theoretical approximation of mean residence times, which highlights the importance of the correlation between turbulence quantities and their time derivatives in setting temporal statistics. Finally, whether in a hole or a burst, the straining structure along particle trajectories always evolves self-similarly (in a statistical sense) from shearless two-dimensional to shear bi-axial configurations. We speculate that this latter configuration represents the optimum manner to dissipate locally the available energy.
Finite-size particles modulate wall-bounded turbulence, leading, for the case of spherical particles, to increased drag also owing to the formation of a particle wall layer. Here, we study the effect of particle shape on the turbulence in suspensions of spheroidal particles at volume fraction
$\unicode[STIX]{x1D719}=10\,\%$
and show how the near-wall particle dynamics deeply changes with the particle aspect ratio and how this affects the global suspension behaviour. Direct numerical simulations are performed using a direct-forcing immersed boundary method to account for the dispersed phase, combined with a soft-sphere collision model and lubrication corrections for short-range particle–particle and particle–wall interactions. The turbulence reduces with the aspect ratio of oblate particles, leading to drag reduction with respect to the single-phase flow for particles with aspect ratio
${\mathcal{A}}{\mathcal{R}}\leqslant 1/3$
, when the significant reduction in Reynolds shear stress is more than the compensation by the additional stresses, induced by the solid phase. Oblate particles are found to avoid the region close to the wall, travelling parallel to it with small angular velocities, while preferentially sampling high-speed fluid in the wall region. Prolate particles also tend to orient parallel to the wall and avoid its vicinity. Their reluctance to rotate around the spanwise axis reduces the wall-normal velocity fluctuation of the flow and therefore the turbulence Reynolds stress, similar to oblates; however, they undergo rotations in wall-parallel planes which increase the additional solid stresses due to their relatively larger angular velocities compared to the oblates. These larger additional stresses compensate for the reduction in turbulence activity and lead to a wall drag similar to that of single-phase flows. Spheres on the other hand, form a layer close to the wall with large angular velocities in the spanwise direction, which increases the turbulence activity in addition to exerting the largest solid stresses on the suspension, in comparison to the other studied shapes. Spherical particles therefore increase the wall drag with respect to the single-phase flow.
We study heat transfer in plane Couette flow laden with rigid spherical particles by means of direct numerical simulations. In the simulations we use a direct-forcing immersed boundary method to account for the dispersed phase together with a volume-of-fluid approach to solve the temperature field inside and outside the particles. We focus on the variation of the heat transfer with the particle Reynolds number, total volume fraction (number of particles) and the ratio between the particle and fluid thermal diffusivity, quantified in terms of an effective suspension diffusivity. We show that, when inertia at the particle scale is negligible, the heat transfer increases with respect to the unladen case following an empirical correlation recently proposed in the literature. In addition, an average composite diffusivity can be used to approximate the effective diffusivity of the suspension in the inertialess regime when varying the molecular diffusion in the two phases. At finite particle inertia, however, the heat transfer increase is significantly larger, smoothly saturating at higher volume fractions. By phase-ensemble-averaging we identify the different mechanisms contributing to the total heat transfer and show that the increase of the effective conductivity observed at finite inertia is due to the increase of the transport associated with fluid and particle velocity. We also show that the contribution of the heat conduction in the solid phase to the total wall-normal heat flux reduces when increasing the particle Reynolds number, so that particles of low thermal diffusivity weakly alter the total heat flux in the suspension at finite particle Reynolds numbers. On the other hand, a higher particle thermal diffusivity significantly increases the total heat transfer.
Phytoplankton are the foundation of aquatic food webs. Through photosynthesis, phytoplankton draw down
$\text{CO}_{2}$
at magnitudes equivalent to forests and other terrestrial plants and convert it to organic material that is then consumed by other planktonic organisms in higher trophic levels. Mechanisms that affect local concentrations and velocities are of primary significance to many encounter-based processes in the plankton, including prey–predator interactions, fertilization and aggregate formation. We report results from simulations of sinking phytoplankton, considered as elongated spheroids, in homogenous isotropic turbulence to answer the question of whether trajectories and velocities of sinking phytoplankton are altered by turbulence. We show in particular that settling spheroids with physical characteristics similar to those of diatoms weakly cluster and preferentially sample regions of downwelling flow, corresponding to an increase of the mean settling speed with respect to the mean settling speed in quiescent fluid. We explain how different parameters can affect the settling speed and what underlying mechanisms might be involved. Interestingly, we observe that the increase in the aspect ratio of the prolate spheroids can affect the clustering and the average settling speed of particles by two mechanisms: first is the effect of aspect ratio on the rotation rate of the particles, which saturates faster than the second mechanism of increasing drag anisotropy.
Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990–1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.
We study suspensions of oblate rigid particles in a viscous fluid for different values of the particle volume fractions. Direct numerical simulations have been performed using a direct-forcing immersed boundary method to account for the dispersed phase, combined with a soft-sphere collision model and lubrication corrections for short-range particle–particle and particle–wall interactions. With respect to the single-phase flow, we show that in flows laden with oblate spheroids the drag is reduced and the turbulent fluctuations attenuated. In particular, the turbulence activity decreases to lower values than those obtained by accounting only for the effective suspension viscosity. To explain the observed drag reduction, we consider the particle dynamics and the interactions of the particles with the turbulent velocity field and show that the particle–wall layer, previously observed and found to be responsible for the increased dissipation in suspensions of spheres, disappears in the case of oblate particles. These rotate significantly slower than spheres near the wall and tend to stay with their major axes parallel to the wall, which leads to a decrease of the Reynolds stresses and turbulence production and so to the overall drag reduction.
Childhood trauma increases risk of a range of mental disorders including psychosis. Whereas the mechanisms are unclear, previous evidence has implicated atypical processing of emotions among the core cognitive models, in particular suggesting altered attentional allocation towards negative stimuli and increased negativity bias. Here, we tested the association between childhood trauma and brain activation during emotional face processing in patients diagnosed with psychosis continuum disorders. In particular, we tested if childhood trauma was associated with the differentiation in brain responses between negative and positive face stimuli. We also tested if trauma was associated with emotional ratings of negative and positive faces.
Method
We included 101 patients with a Diagnostic and Statistical Manual of Mental Disorders (DSM) schizophrenia spectrum or bipolar spectrum diagnosis. History of childhood trauma was obtained using the Childhood Trauma Questionnaire. Brain activation was measured with functional magnetic resonance imaging during presentation of faces with negative or positive emotional expressions. After the scanner session, patients performed emotional ratings of the same faces.
Results
Higher levels of total childhood trauma were associated with stronger differentiation in brain responses to negative compared with positive faces in clusters comprising the right angular gyrus, supramarginal gyrus, middle temporal gyrus and the lateral occipital cortex (Cohen's d = 0.72–0.77). In patients with schizophrenia, childhood trauma was associated with reporting negative faces as more negative, and positive faces as less positive (Cohen's d > 0.8).
Conclusions
Along with the observed negativity bias in the assessment of emotional valence of faces, our data suggest stronger differentiation in brain responses between negative and positive faces with higher levels of trauma.
We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.