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Known as the 'Gate to Mecca' or 'Bride of the Red Sea', Jeddah has been a gateway for pilgrims travelling to Mecca and Medina and a station for international trade routes between the Indian Ocean and the Mediterranean for centuries. Seen from the perspective of its diverse population, this first biography of Jeddah traces the city's urban history and cosmopolitanism from the late Ottoman period to its present-day claim to multiculturalism, within the conservative environment of the Arabian Peninsula. Contextualising Jeddah with developments in the wider Muslim world, Ulrike Freitag investigates how different groups of migrants interacted in a changing urban space and how their economic activities influenced the political framework of the city. Richly illustrated, this study reveals how the transformation of Jeddah's urban space, population and politics has been indicative of changes in the wider Arab and Red Sea region, re-evaluating its place in the Middle East at a time when both its cosmopolitan practices and old city are changing dramatically against a backdrop of modernisation and Saudi nation-building.
Using the term “legacy” for a career as productive, insightful, and pathbreaking as Chris Bayly's is doubtless an understatement. The movement in his publications from the transitional world in the Indian subcontinent leading to British imperialism, through aspects of high empire in India, to world history through both case studies and broader context for grasping the implications of a changing world, provides valuable analyses for all of us, if not a pattern many could replicate. Perhaps what ought to be noted here is the experience, common to many of us working across a very broad range of problematics and focal points, to have found Bayly there, before us.
We compared elastic moduli in polar firn derived from diving wave refraction seismic velocity analysis, firn-core density measurements and microstructure modelling based on firn-core data. The seismic data were obtained with a small electrodynamic vibrator source near Kohnen Station, East Antarctica. The analysis of diving waves resulted in velocity–depth profiles for different wave types (P-, SH- and SV-waves). Dynamic elastic moduli of firn were derived by combining P- and S-wave velocities and densities obtained from firn-core measurements. The structural finite-element method (FEM) was used to calculate the components of the elastic tensor from firn microstructure derived from X-ray tomography of firn-core samples at depths of 10, 42, 71 and 99 m, providing static elastic moduli. Shear and bulk moduli range from 0.39 to 2.42 GPa and 0.68 to 2.42 GPa, respectively. The elastic moduli from seismic observations and the structural FEM agree within 8.5% for the deepest achieved values at a depth of 71 m, and are within the uncertainty range. Our observations demonstrate that the elastic moduli of the firn can be consistently obtained from two independent methods which are based on dynamic (seismic) and static (tomography and FEM) observations, respectively, for deeper layers in the firn below ~10 m depth.
Capillary collimators have found a number of uses in fluorescence, diffraction and other x-ray fields. Most of these applications are realized with single, straight glass capillaries. Focussing of synchrotron x-radiation beams has been shown with tapered capillaries. In addition, numerous straight and bent capillaries, bundled into lens-like optics, offer experimenters many other possibilities for better use of the x-radiation from tubes, synchrotron radiation, and plasma sources or the x-ray intensity collected from samples.
The evaluation and understanding of the x-ray diffraction properties of multilayer structures is critical in predicting the degree of success in their utilization in x-ray optics applications. A key material parameter affecting the diffracting efficiency of multilayer structures is the roughness of the interfaces between the deposited layers. This paper will use measured roughness to predict the integral reflection coefficient as a function of diffraction order for several multilayer structures.
We have made atomic force microscope (AFM) measurements of the detailed displacement distribution for me surface roughness of W/C and W/Si multilayer structures. This information has been introduced into a theoretical model to predict the reduction of the integral reflection coefficient induced by surface roughness. In a fashion analogous to the Debye-Waller factor, this reduction in diffracted intensity is predicted to be strongly dependent on the diffraction order. These predictions have been compared with experimental integral reflection coefficient data. The measured diffraction results indicate a greater reduction in reflection than is predicted by the AFM measurements. A possible explanation for this discrepancy is that the AFM measurements underestimate the roughness. Possible reasons for the differences between these methods will be discussed.
Previous studies of conduct disorder (CD) have reported structural and functional alterations in the limbic system. However, the white matter tracts that connect limbic regions have not been comprehensively studied. The uncinate fasciculus (UF), a tract connecting limbic to prefrontal regions, has been implicated in CD. However, CD-related alterations in other limbic tracts, such as the cingulum and the fornix, have not been investigated. Furthermore, few studies have examined the influence of sex and none have been adequately powered to test whether the relationship between CD and structural connectivity differs by sex. We examined whether adolescent males and females with CD exhibit differences in structural connectivity compared with typically developing controls.
We acquired diffusion-weighted magnetic resonance imaging data from 101 adolescents with CD (52 females) and 99 controls (50 females). Data were processed for deterministic spherical deconvolution tractography. Virtual dissections of the UF, the three subdivisions of the cingulum [retrosplenial cingulum (RSC), parahippocampal and subgenual cingulum], and the fornix were performed and measures of fractional anisotropy (FA) and hindrance-modulated orientational anisotropy (HMOA) were analysed.
The CD group had lower FA and HMOA in the right RSC tract relative to controls. Importantly, these effects were moderated by sex – males with CD significantly lower FA compared to male controls, whereas CD and control females did not differ.
Our results highlight the importance of considering sex when studying the neurobiological basis of CD. Sex differences in RSC connectivity may contribute to sex differences in the clinical presentation of CD.
Traits of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are strongly associated in children and adolescents, largely due to genetic factors. Less is known about the phenotypic and aetiological overlap between ADHD and ASD traits in adults.
We studied 6866 individuals aged 20–28 years from the Swedish Study of Young Adult Twins. Inattention (IA) and hyperactivity/impulsivity (HI) were assessed using the WHO Adult ADHD Self-Report Scale-V1.1. Repetitive and restricted behaviours (RRB) and social interaction and communication (SIC) were assessed using the Autism-Tics, ADHD, and other Comorbidities inventory. We used structural equation modelling to decompose covariance between these ADHD and ASD trait dimensions into genetic and shared/non-shared environmental components.
At the phenotypic level, IA was similarly correlated with RRB (r = 0.33; 95% Confidence Interval (CI) 0.31–0.36) and with SIC (r = 0.32; 95% CI 0.29–0.34), whereas HI was more strongly associated with RRB (r = 0.38; 95% CI 0.35–0.40) than with SIC (r = 0.24; 95% CI 0.21–0.26). Genetic and non-shared environmental effects accounted for similar proportions of the phenotypic correlations, whereas shared environmental effects were of minimal importance. The highest genetic correlation was between HI and RRB (r = 0.56; 95% 0.46–0.65), and the lowest was between HI and SIC (r = 0.33; 95% CI 0.23–0.43).
We found evidence for dimension-specific phenotypic and aetiological overlap between ADHD and ASD traits in adults. Future studies investigating mechanisms underlying comorbidity between ADHD and ASD may benefit from exploring several symptom-dimensions, rather than considering only broad diagnostic categories.
Many people with mental illness do not seek professional help. Beliefs about the causes of their current health problem seem relevant for initiating treatment. Our aim was to find out to what extent the perceived causes of current untreated mental health problems determine whether a person considers herself/himself as having a mental illness, perceives need for professional help and plans to seek help in the near future.
In a cross-sectional study, we examined 207 untreated persons with a depressive syndrome, all fulfilling criteria for a current mental illness as confirmed with a structured diagnostic interview (Mini International Neuropsychiatric Interview). The sample was recruited in the community using adverts, flyers and social media. We elicited causal explanations for the present problem, depression literacy, self-identification as having a mental illness, perceived need for professional help, help-seeking intentions, severity of depressive symptoms (Patient Health Questionnaire – Depression), and whether respondents had previously sought mental healthcare.
Most participants fulfilled diagnostic criteria for a mood disorder (n = 181, 87.4%) and/or neurotic, stress-related and somatoform disorders (n = 120, 58.0%) according to the ICD-10. N = 94 (45.4%) participants had never received mental health treatment previously. Exploratory factor analysis of a list of 25 different causal explanations resulted in five factors: biomedical causes, person-related causes, childhood trauma, current stress and unhealthy behaviour. Attributing the present problem to biomedical causes, person-related causes, childhood trauma and stress were all associated with stronger self-identification as having a mental illness. In persons who had never received mental health treatment previously, attribution to biomedical causes was related to greater perceived need and stronger help-seeking intentions. In those with treatment experience, lower attribution to person-related causes and stress were related to greater perceived need for professional help.
While several causal explanations are associated with self-identification as having a mental illness, only biomedical attributions seem to be related to increase perceived need and help-seeking intentions, especially in individuals with no treatment experiences. Longitudinal studies investigating causal beliefs and help-seeking are needed to find out how causal attributions guide help-seeking behaviour. From this study it seems possible that portraying professional mental health treatment as not being restricted to biomedical problems would contribute to closing the treatment gap for mental disorders.
In this study, the three-dimensional (3-D) microstructure of polar firn is investigated by means of X-ray microfocus computer tomography (mCT). Basic topological properties including the Euler and coordination numbers are derived from the reconstructed 3-D volume images. It is shown that sample volumes of about 4 cm3 are representative for polar firn in terms of their connectivity. The connectivity function defined as the change of Euler number with structure size is calculated via image-processing routines. It is used to split the ice phase at small bridges into single crystallite agglomerates. The bond-size distributions and the mean size of the agglomerates are estimated. All μCT measurements were carried out on the uppermost 9 m of a shallow firn core (B35) drilled during the 2005/06 field campaign at Kohnen station, Dronning Maud Land (DML), Antarctica. The results are compared with estimates from classical two-dimensional (2-D) surface section observations. The 3-D approach confirms the linear relationship between coordination number and density which hitherto has only been derived from 2-D observations. Layers of buried snow dunes show a stronger connectivity than layers of moderate crystal size and density. The formation of agglomerates made of crystallites is a common feature of polar firn in DML. It is proposed that the growth of agglomerates leads to reduced critical densities for the transition between the densification regime of grain boundary sliding and plastic deformation.
In this study a powerful tool to investigate the permeabilities and effective diffusion coefficients of polar firn is presented using a combination of an experimental method for three-dimensional pore-structure reconstruction and two models to simulate advective and diffusive transports of gases through the pore space. the reconstruction follows a semi-automated digital analysis of serial surface sections. the simulations are based on a three-dimensional lattice Boltzmann formulation. They separately solve the Navier–Stokes equation and the diffusive transport equations. In a first application, effective diffusion coefficients and permeabilities are calculated from firn samples of a core drilled during the North Greenland Traverse 1993–95. the estimated relationships of diffusivity and permeability to the open porosity are expressed by power-law functions with exponents 2.1 and 3.4, respectively.