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The mechanism through which developmental programming of offspring overweight/obesity following in utero exposure to maternal overweight/obesity operates is unknown but may operate through biologic pathways involving offspring anthropometry at birth. Thus, we sought to examine to what extent the association between in utero exposure to maternal overweight/obesity and childhood overweight/obesity is mediated by birth anthropometry. Analyses were conducted on a retrospective cohort with data obtained from one hospital system. A natural effects model framework was used to estimate the natural direct effect and natural indirect effect of birth anthropometry (weight, length, head circumference, ponderal index, and small-for-gestational age [SGA] or large-for-gestational age [LGA]) for the association between pre-pregnancy maternal body mass index (BMI) category (overweight/obese vs normal weight) and offspring overweight/obesity in childhood. Models were adjusted for maternal and child socio-demographics. Three thousand nine hundred and fifty mother–child dyads were included in analyses (1467 [57.8%] of mothers and 913 [34.4%] of children were overweight/obese). Results suggest that a small percentage of the effect of maternal pre-pregnancy BMI overweight/obesity on offspring overweight/obesity operated through offspring anthropometry at birth (weight: 15.5%, length: 5.2%, head circumference: 8.5%, ponderal index: 2.2%, SGA: 2.9%, and LGA: 4.2%). There was a small increase in the percentage mediated when gestational diabetes or hypertensive disorders were added to the models. Our study suggests that some measures of birth anthropometry mediate the association between maternal pre-pregnancy overweight/obesity and offspring overweight/obesity in childhood and that the size of this mediated effect is small.
To characterize the association of longitudinal changes in maternal anthropometric measures with neonatal anthropometry and to assess to what extent late-gestational changes in maternal anthropometry are associated with neonatal body composition.
In a prospective cohort of pregnant women, maternal anthropometry was measured at six study visits across pregnancy and after birth, neonates were measured and fat and lean mass calculated. We estimated maternal anthropometric trajectories and separately assessed rate of change in the second (15–28 weeks) and third trimester (28–39 weeks) in relation to neonatal anthropometry. We investigated the extent to which tertiles of third-trimester maternal anthropometry change were associated with neonatal outcomes.
Women were recruited from twelve US sites (2009–2013).
Non-obese women with singleton pregnancies (n 2334).
A higher rate of increase in gestational weight gain was associated with larger-birth-weight infants with greater lean and fat mass. In contrast, higher rates of increase in maternal anthropometry measures were not associated with infant birth weight but were associated with decreased neonatal lean mass. In the third trimester, women in the tertile of lowest change in triceps skinfold (−0·57 to −0·06 mm per week) had neonates with 35·8 g more lean mass than neonates of mothers in the middle tertile of rate of change (−0·05 to 0·06 mm per week).
The rate of change in third-trimester maternal anthropometry measures may be related to neonatal lean and fat mass yet have a negligible impact on infant birth weight, indicating that neonatal anthropometry may provide additional information over birth weight alone.
Trapped waves can exist in the presence of bodies in open water, and also in channels of finite width. Various examples are found for bodies that support trapped waves in channels, including floating and submerged bodies and bottom-mounted cylinders. Different types of trapping are considered where the body is fixed or free to move in response to the oscillatory pressure. In some cases both types are supported by the same body. In most cases for fixed bodies the fluid motion is antisymmetric about the centreline of the channel, but special body shapes exist where the trapped mode is asymmetric. For free bodies the trapping modes and body motions are symmetric about the centreline if the body is floating or antisymmetric if it is submerged.
Lectotypes are designated for eight names in Eriocaulon in tropical Asia, namely E. alatum, E. hamiltonianum, E. hookerianum, E. infirmum, E. lanigerum, E. nautiliforme, E. nigrum and E. ubonense. Additional information on the lectotype of Eriocaulon quinquangulare is given.
We wanted to present our experience with the extended endoscopic approach to clival pathology, focusing on cerebrospinal fluid leak and reconstruction challenges.
We examined a consecutive series of 37 patients undergoing the extended endoscopic approach for skull base tumours, 9 patients with clival pathology. Patients were examined for the incidence of post-operative cerebrospinal fluid leak in relation to tumour pathology, location, size, reconstruction and lumbar drain.
The overall incidence of post-operative cerebrospinal fluid leak was 10.8 per cent. Seventy-five per cent of patients who had a post-operative cerebrospinal fluid leak underwent a transclival approach (p < 0.05). All patients with clival pathology who underwent an intradural dissection had a post-operative cerebrospinal fluid leak (p < 0.05).
Post-operative cerebrospinal fluid leak rates after the extended endoscopic approach have improved significantly after advancements including the vascularised nasoseptal flap. Despite this, transclival approaches continue to pose much difficulty. Further investigation is necessary to develop technical improvements that can meet the unique challenges associated with this region.
The paper describes a process which allows a vertical circular cylinder subject to plane monochromatic surface gravity waves to appear invisible to the far-field observer. This is achieved by surrounding the cylinder with an annular region of variable bathymetry. Two approaches are taken to investigate this effect. First a mild-slope approximation is applied to the governing linearised three-dimensional water wave equations to formulate a depth-averaged two-dimensional wave equation with varying wavenumber over the variable bathmetry. This is then solved by formulating a domain integral equation, solved numerically by discretisation. For a given set of geometrical and wave parameters, the bathymetry is selected by a numerical optimisation process and it is shown that the scattering cross-section is reduced towards zero with increasing refinement of the bathymetry. A fully three-dimensional boundary-element method, based on the WAMIT solver (see www.wamit.com) but adapted here to allow for depressions in the bed, is used to assess the accuracy of the mild-slope results and then further numerically optimise the bathymetry towards a cloaking structure. Numerical results provide strong evidence that perfect cloaking is possible for the fully three-dimensional problem. One practical application of the results is that cloaking implies a reduced mean drift force on the cylinder.
We have used high-resolution, HST WFC3/IR, near-infrared imaging to conduct a detailed bulge-disk decomposition of the morphologies of ≃ 200 of the most massive (M* > 1011 M⊙) galaxies at 1 < z < 3 in the CANDELS-UDS field. We find that, while such massive galaxies at low redshift are generally bulge-dominated, at redshifts 1<z<2 they are predominantly mixed bulge+disk systems, and by z > 2 they are mostly disk-dominated. Interestingly, we find that while most of the quiescent galaxies are bulge-dominated, a significant fraction (25–40%) of the most quiescent galaxies, have disk-dominated morphologies. Thus, our results suggest that the physical mechanisms which quench star-formation activity are not simply connected to those responsible for the morphological transformation of massive galaxies.
In-situ and ex-situ measurements of environmental radioactivity were made on the iThemba LABS (iTL) grounds in South Africa. The MEDUSA and HPGe detector systems were used to make in-situ and ex-situ measurements, respectively. The MEDUSA was mounted ~0.5 m above the ground on a 4 × 4 vehicle to traverse [at ~2m∙s-1] the accessible portions of the iTL grounds. Spatial data (via a GPS receiver) were acquired every 1 s, and γ-ray spectra every 2 s. MEDUSA count rate maps were produced to show the spatial distribution of radioactivity on the grounds. The HPGe was used to measure the radioactivity in soil (and also in some grass) samples collected at particular spots on the iTL grounds. The sampled spots include six identified high activity spots (“hot spots”) and two “calibration spots”. The activity concentrations were determined for both the natural and anthropogenic radionuclides. The absorbed and effective doses (from external γ-ray irradiation) were also determined for the natural and anthropogenic radionuclides. The maximum effective dose to humans on the iTL grounds as a result of external exposure to natural and anthropogenic radionuclides was found to be well below the regulatory 1 mSv per year per member of public.
The Duke Twins Study of Memory in Aging is an ongoing, longitudinal study of cognitive change and dementia in the population-based National Academy of Sciences-National Research Council (NAS-NRC) Twin Registry of World War II Male Veterans. The primary goal of this study has been to estimate the overall genetic and environmental contributions to dementia with a specific focus on Alzheimer's disease. An additional goal has been to examine specific genetic and environmental antecedents of cognitive decline and dementia. Since 1989, we have completed 4 waves of data collection. Each wave included a 2-phase telephone cognitive screening protocol, followed by an in-home standardized clinical assessment for those with suspected dementia. For many participants, we have obtained postmortem neuro-pathological confirmation of the diagnosis of dementia. In addition to data on cognition, we have also collected information on occupational history, medical history, medications and other lifetime experiences that may influence cognitive function in late life. We provide an overview of the study's methodology and describe the focus of recent research.
The use of boron as a sintering aid reduces the sintering temperature, enhances the sintering density, and improves the microwave properties of Ba(Cd1/3Ta2/3)O3 ceramic dielectrics. Observations by transmission electron microscopy indicate that the liquid sintering mechanism contributes to the improvement in sintering density for boron concentrations exceeding 0.5 wt%. The introduction of as small as 0.01% boron also results in the production of high-density samples (∼95%), presumably indicating that a point defect mechanism may also play an important role in the sintering process. X-ray diffraction data combined with high-resolution transmission electron microscopy images show that boron-doped Ba(Cd1/3Ta2/3)O3 ceramic material has a well-ordered hexagonal structure. Annealing treatment is found to improve the microwave properties. The best sample has a dielectric constant of 32, a temperature coefficient of resonant frequency of 80 ± 15 ppm/°C, and a quality factor of >25,000 at 2 GHz.
The microstructure of Ba(Cd1/3Ta2/3)O3 ceramics with boron additive was investigated by high-resolution and analytical electron microscopy. Superlattice reflections were present at positions of (h ± 1/3, k ± 1/3, l ± 1/3) away from the fundamental reflections in the  zone diffraction pattern for the pseudocubic perovskite unit cell. Lattice images showed a well-ordered structure with hexagonal symmetry. No boron segregation and amorphous phase was observed along grain boundaries. An amorphous phase rich in boron-oxide was observed to form pockets partially penetrating along multiple grain junctions.
The interaction of a helicopter tail rotor blade with the tip vortex system from the main rotor is a significant source of noise and, in some flight states, can produce marked reductions in control effectiveness. This paper describes a series of wind-tunnel tests to simulate tail rotor blade vortex interaction with a view to providing data for the development and validation of numerical simulations of the phenomenon. In the experiments, which were carried out in the Argyll wind-tunnel of Glasgow University, a single-bladed rotor located in the tunnel’s contraction was used to generate the tip vortex which travelled downstream into the working section where it interacted with a model tail rotor. The tail rotor was instrumented with miniature pressure transducers that measured the aerodynamic response during the interaction. The results suggest that the rotor blade vortex interaction is similar in form to that measured at much higher spatial resolution on a fixed, non-rotating blade. The combination of the two datasets, therefore, provides a valuable resource for the development and validation of predictive schemes.
Trapped modes in the linearized water-wave problem are free oscillations of the fluid which
have finite energy. They are known to exist at isolated frequencies in the presence of
certain special structures. The existence of a trapped mode implies the non-uniqueness,
or non-existence, of the solution to physically relevant radiation and diffraction problems
for such a structure.
Previous work on the three-dimensional problem has established the existence of vertically
axisymmetric structures that support trapped modes with either a single interior free surface,
or two concentric interior free surfaces. In the present work the existence of several new types
of trapping structures is established. These include non-axisymmetric structures with a single
interior free surface and various structures with multiple interior free surfaces. The method
used is an indirect one in which flow fields without wave radiation are specified, and
corresponding structures are found by constructing suitable stream surfaces. Computations
of the added-mass coefficients for these structures provide independent support for the
existence of a trapping mode and illustrate their hydrodynamic characteristics at other
In March 1999, a large community outbreak of Escherichia coli O157 infection occurred in North Cumbria. A total of 114 individuals were reported to the Outbreak Control Team (OCT); 88 had laboratory confirmed E. coli O157. Twenty-eight (32%) of the confirmed cases were admitted to hospital, including three children (3·4%) with haemolytic uraemic syndrome. There were no deaths. A case-control study found that illness was strongly associated with drinking pasteurized milk from a local farm (P=<0·0001) on single variable analysis. Microbiological investigations at the farm revealed E. coli O157 phage type (PT) 21/28 VT 2 which was indistinguishable from the human isolates by pulsed field gel electrophoresis. At the time of occurrence this was the largest E. coli O157 outbreak in England and Wales and the first E. coli O157 PT 21/28 VT 2 outbreak associated with pasteurized milk. This outbreak highlights lessons to be learnt regarding on-farm pasteurization.
Single-phase Ba(Cd1/3Ta2/3)O3 ceramics have been produced using conventional powder processing methods. In our initial investigations, 2wt% ZnO powder was added to act as a sintering aid since a high-density ceramic was not formed from solid-state diffusion alone. The resulting Ba(Cd0.327Zn0.006Ta2/3)O3 material sintered at 1550° C exhibits a dielectric constant of ∼33 and loss tangent of <5×10−5 at 2 GHz. In our more recent work, we have used boron as a sintering aid to facilitate sintering at temperatures as low as 1300° C, enhance the structural quality and improve the microwave properties of Ba(Cd1/3Ta2/3)O3 dielectrics. TEM results indicate that the liquid sintering mechanism is an important factor for boron concentrations exceeding 0.5wt%, while a point defect mechanism plays the dominant role at lower boron concentrations. The presence of superstructure peaks and splitting of the (220) and (214) peaks in X-ray diffraction spectra are direct evidence for the distortion from cubic symmetry as a result of Cd and Ta ordering on the B-site.
Ab-initio electronic structure calculations within the local density functional approximation have been used to give insight into the unusual properties of this class of materials. In both Ba(Zn1/3Ta2/3)O3 and Ba(Cd/3Ta2/3)O3, the conduction band maximum and valence band minimum are composed of mostly weakly itinerant Ta 5d-and Zn-3d/Cd-4d levels, respectively. The covalent nature of the directional d-electron bonding in these high-Z oxides plays an important role in producing a more rigid lattice with higher melting points and enhanced phonon energies, and possibly inherently lower intrinsic microwave loss than comparable ionic materials.
Reactive MBE growth was used to synthesize ferromagnetic Cr-doped GaN and AlN thin films with Curie temperatures above 900K. 2% Cr-doped GaN and 7% Cr-doped AlN were found to have a saturation magnetization moment of 0.42 and 0.6 μB/Cr atom, indicating that ∼14% and ∼20% of the Cr, respectively, are magnetically active. Structural characterization using X-ray diffraction (XRD) and transmission electron microscopy (TEM) did not find evidence of a ferromagnetic secondary phase. Electrical characterization indicate that the resistivity of the Cr-doped GaN films depends exponentially on temperature as R=Roexp[(To/T)1/2], characteristic of variable range hopping. In contrast, Cr-doped AlN films are highly resistive. Local spin density functional calculations predict that Cr forms a deep level defect in both systems and the t2 level falls approximately at midgap. Our theoretical and experimental results indicate that ferromagnetism in Cr-doped GaN and AlN arises as a result of the double exchange mechanism within the partially filled Cr t2 band.
Ordered structures of Ba(Cd1/3Ta2/3)O3 ceramics with and without boron additive were investigated systemically by electron diffraction and high resolution transmission electron microscopy. The results showed a well-ordered structure of 1:2 with hexagonal symmetry for Ba(Cd1/3Ta2/3)O3 with boron additive. No significant changes in ordered structures were observed after long-period annealing. The 1:2 ordered domain structures (average domain size ∼18 nm) and high-density domain boundaries induced by ordering were observed for Ba(Cd1/3Ta2/3)O3 without boron additive sintered at relatively high temperature. The sintering process has a profound influence on the microstructure of Ba(Cd1/3Ta2/3)O3 ceramics.