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Subglacial hydrology plays a key role in many glaciological processes, including ice dynamics via the modulation of basal sliding. Owing to the lack of an overarching theory, however, a variety of model approximations exist to represent the subglacial drainage system. The Subglacial Hydrology Model Intercomparison Project (SHMIP) provides a set of synthetic experiments to compare existing and future models. We present the results from 13 participating models with a focus on effective pressure and discharge. For many applications (e.g. steady states and annual variations, low input scenarios) a simple model, such as an inefficient-system-only model, a flowline or lumped model, or a porous-layer model provides results comparable to those of more complex models. However, when studying short term (e.g. diurnal) variations of the water pressure, the use of a two-dimensional model incorporating physical representations of both efficient and inefficient drainage systems yields results that are significantly different from those of simpler models and should be preferentially applied. The results also emphasise the role of water storage in the response of water pressure to transient recharge. Finally, we find that the localisation of moulins has a limited impact except in regions of sparse moulin density.
Patients with psychiatric conditions are often referred for a brain scan during the course of their diagnostic workup.
The aim of our study is to determine frequency and type of organic brain pathology, the relationship to age, gender and psychiatric diagnosis.
We investigated magnetic resonance imaging and computed tomography brain scans from consecutively referred patients over a 10-year period (January 2002-December 2011). The reasons for referral, estimated psychiatric diagnosis, and the pathology discovered for each patient were registered.
A total of 34% of patients demonstrated organic brain pathology, of which 32.8% were considered clinically relevant. This represents a higher frequency of relevant pathology than reported in healthy subjects. Age (P < 0.001) and diagnosis (P = 0.016) were the most important determinants for frequency of pathological findings.
Brain imaging in clinical psychiatry resulted in approximately 30% positive findings mainly associated with increasing pathologies with age, but also with diagnosis.
Declaration of interest
Both T.O.D. and M.K.B. have received honorary from Novartis for scientific lectures about multiple sclerosis. M.K.B. also received honoraria from Biogen for scientific lectures. The other authors have no conflicts of interest.
Catholic social teaching (CST) has long endorsed the right of all workers to unionize. However, many US Catholics exhibit an antiunion bias. In addition, Catholic institutions have engaged in union busting, thereby flouting CST. Focusing on the recent efforts of adjuncts to unionize at Catholic universities, this article argues that union busting jeopardizes the faith and conscience formation of students and undermines the evangelizing mission of Catholic universities. The article debunks the appeal to religious liberty by Catholic institutions to circumvent the National Labor Relations Board's injunctions to allow adjuncts to unionize. It also refutes the argument that the National Labor Relations Act imposes a style of collective bargaining contrary to the harmonious vision of labor relations in CST. Succinctly stated, the article contends there is no legitimate reason for Catholic universities to thwart the unionization efforts of adjuncts, particularly given the systematically unjust work conditions many of them face.
Laser and oven annealing effects on hydrogen concentration, hydrogen diffusion and material microstructure in hydrogenated amorphous silicon films deposited on crystalline silicon substrates are compared. For laser annealing, a 6 W green (532 nm) continuous wave laser with 100 µm focus diameter was applied and samples of about 1 cm2 were scanned in ambient with a line distance of 50 µm and at a speed of 1 – 100 mm/s. Hydrogen content and microstructure were measured by infrared spectroscopy, and hydrogen diffusion was investigated by secondary ion mass spectroscopy (SIMS) measurements of depth profiles of deuterium and hydrogen in layered structures of deuterated and hydrogenated material. The results show that in both annealing experiments hydrogen diffuses predominantly in form of atoms although some formation of H2 molecules cannot be excluded. By comparison of laser and oven treatment, an effective temperature describing the laser treated state can be defined. Furthermore, the temperature of the thin silicon film during laser treatment is estimated.
Giant Magnetoresistance (GMR) is reported in as-deposited Ag1−xCox (x = 0.26–0.53) films co-sputtered on Si from separate Ag and Co targets. GMR ratios (10 K Oe Maximum field) exceeding 0.50 and 0.19 at 5 and 295 K, respectively, are observed for the Ag067Co033 films deposited at ≃28 to 175 °C. The Maximum ratios of 0.55 and 0.24 occur at a substrate temperature of ≃125 °C for these films. The ratios decrease rapidly for the films deposited at temperatures > 175 °C and reduce to ≃0.15 and 0.04 at deposition temperatures >300 °C. This deposition temperature dependence of GMR ratios is interpreted in terms of the change in the spin-dependent interfacial electron scatterings due to the change in the size and number of ferromagnetic Co particles within the electron mean free path. The initial increase and the subsequent decrease in GMR ratios with increasing deposition temperature are attributed to the increase in the mean free path, and the Co and Ag particle size, respectively. Changes in mean free path are obtained from the resistivities of these films while changes in Ag and Co particles are deduced mainly from the X-ray diffraction patterns, transmission electron Micrographs, and the coercivities of these films.
The impact of projected regional climate change on the migration of cabbage stem weevil (Ceutorhynchus pallidactylus) to oilseed rape crops in the Grand Duchy of Luxembourg is evaluated for past and future time spans. Several threshold-based statistical models for the emergence and the main migration of C. pallidactylus were chosen from the literature and combined with selected regional climate change projections of the EU ENSEMBLES project. Additionally, a simple degree-day based model was used to assess the plant development under expected climate change conditions. An earlier onset as well as a prolongation of the possible emergence times and the main migration periods was detected. The onset of stem elongation of oilseed rape was predicted to occur 3·0 days earlier per decade, while emergence of C. pallidactylus was expected to occur between 3·0 and 3·3 days earlier per decade. The main migration period of the weevil to the field may start 2·0 days earlier per decade under future climate conditions. Additionally, the time span of possible migration is prolonged for about 30 days under projected future climate conditions.
Hydrogen diffusion and solubility effects in hydrogenated amorphous and microcrystalline silicon films are reviewed. Various diffusion-related effects have been observed which need to be considered in models of hydrogen diffusion. Hydrogen solubility is found to affect hydrogen incorporation and hydrogen transport.
The structure of a-Si:H, deposited at rates in excess of 100Å/s by the hot wire chemical vapor deposition (HWCVD) technique, has been examined by x-ray diffraction (XRD), Raman spectroscopy, H evolution, and small-angle x-ray scattering (SAXS). As the film deposition rate (Rd) is increased, we find that the XRD, Raman and the H evolution peak curves are invariant with Rd, and exhibit structure consistent with state-of-the-art, compact a-Si:H films deposited at low Rd. The only exception is the SAXS signal, which increases by a factor of ∼100 over that for our best low Rd films. We relate changes in the film electronic structure (Urbach edge) to the increase in the SAXS signals. We also note the invariance of the saturated defect density versus Rd, and discuss possible reasons why the increase in the SAXS does not play a role in the Staebler-Wronski Effect for this type of material. Finally, device results are presented.
The effusion of the rare gases neon and helium, as well as of hydrogen, was studied for plasma deposited (boron-doped and undoped) hydrogenated amorphous silicon films, grown at various substrate temperatures. Rare gas atoms were incorporated into the material during the growth process or by ion implantation. The results suggest that helium and neon effusion spectra give information on the material microstructure.
Microcrystalline silicon (μc-Si:H) solar cells were prepared in a wide range of deposition parameters using 13.56 MHz plasma-enhanced chemical vapour deposition (PECVD). The best μc-Si:H solar cells were prepared close to the transition to amorphous silicon (a-Si:H) growth at very high deposition pressures (∼10 Torr) showing solar cell efficiencies up to 8.0 % at a deposition rate of 5ÊÅ/s. Investigations of the solar cells were performed by Raman spectroscopy and transmission electron microscopy (TEM). TEM measurements revealed similar structural properties with similar high crystalline volume fractions for these cells although they showed distinctly different efficiencies. However, an increased amorphous volume fraction was detected by Raman spectroscopy for the low efficiency cells prepared at low deposition pressures. This result is attributed to an increased ion bombardment at low pressures.
High resolution transmission electron microscopy during in‐situ quenching of YBa2Cu3Oz is used to study the kinetics of microdomain formation during oxygen loss in this system. Image simulations based on atomic models of oxygen‐vacancy order in the basal plane of this material generated by Monte Carlo calculations are used to interpret high resolution micrographs of the structures obtained by quenching. The observed domain structures agree well with those obtained from the simualtions.
This paper reports on the structures and properties of Y1Ba2Cu3O9−x samples prepared in precisely controlled oxygen environments using a solid-state ionic technique. By titrating out oxygen at low temperatures, orthorhombic Y1Ba2Cu3O9−x samples were prepared with oxygen contents below 6.50. Resistivity and magnetometry studies indicated that these reduced, orthorhombic samples were marginally superconducting, with their superconductivity probably arising from local regions of higher oxygen content.
The change of the hydrogen effusion spectra and of deuterium in-diffusion profiles in a-Si:H and a-Si alloys by boron doping is attributed to a Fermi level dependent change of the Si-H bond rupture energy. For low and high substrate temperatures additional effects occur due to structural heterogeneity.