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Background: Approximately 12-15% of patients with intracranial aneurysms (IA) have affected first-degree relatives, and are considered to have familial intracranial aneurysms (FIA). Individuals with FIA are at higher risk for aneurysm formation and subarachnoid hemorrhage. THSD1 is the only gene to be associated with nonsyndromic FIA at this time. Our study aims to find rare DNA variants that are major risk factors for FIA in our cohort of patients. Methods: To date we have enrolled 37 affected and 31 unaffected people from 16 families. We have done exome or genome sequencing on at least 1 person from each of 12 families. Results: A rare p.(R686W) variant in THSD1 was found in 1/12 families, but did not cosegregate fully with disease. While less attractive as the primary cause of FIA, we cannot rule out the potential modifying effects of THSD1 p.(R686W) in this family. A second candidate, an extracellular matrix gene within a chromosomal region previously implicated by familial mapping studies, contains rare variants in 4/12 of our families. All four variants are predicted to be damaging. Conclusions: Alongside environmental risk factors, individual FIA families may also have complex rare variant contributions to their disease, such as digenic and multi-locus contributions.
We present an in-depth study of metal-poor stars, based high resolution spectra combined with newly released astrometric data from Gaia, with special attention to observational uncertainties. The results are compared to those of other studies, including Gaia benchmark stars. Chemical evolution models are discussed, highlighting few puzzles that are still affecting our understanding of stellar nucleosynthesis and of the evolution of our Galaxy.
After a little more than forty years of work related to the interplanetary plasma and the heliosphere the IAU's Commission 49 was formally discontinued in 2015. The commission started its work when the first spacecraft were launched to measure the solar wind in–situ away from Earth orbit, both inward and outward from 1 AU. It now hands over its activities to a new commission during an era of space research when Voyager 1 measures in–situ the parameters of the local interstellar medium at the edge of the heliosphere. The commission will be succeeded by C.E3 with a similar area of responsibility but with more focused specific tasks that the community intends to address during the coming several years. This report includes a short description of the motivation for this commission and of the historical context. It then describes work from 2012 to 2015 during the present solar cycle 24 that has been the weakest in the space era so far. It gave rise to a large number of studies on solar energetic particles and cosmic rays. Other studies addressed e.g. the variation of the solar wind structure and energetic particle fluxes on long time scales, the detection of dust in the solar wind and the Voyager measurements at the edge of the heliosphere. The research is based on measurements from spacecraft that are at present operational and motivated by the upcoming Solar Probe + and Solar Orbiter missions to explore the vicinity of the Sun. We also report here the progress on new and planned radio instruments and their importance for heliospheric studies. Contributors to this report are Carine Briand, Yoichiro Hanaoka, Eduard Kontar, David Lario, Ingrid Mann, John D. Richardson.
Common pharmacological treatments of mood disorders aim to modulate serotonergic neurotransmission and enhance serotonin levels in the brain. Brain serotonin levels are dependent on the availability of its food-derived precursor essential amino acid tryptophan (Trp). We tested the hypothesis that delivery of Trp via food may serve as an alternative treatment, and examined the effects of a Trp-rich, bioavailable dietary supplement from egg protein hydrolysate on cognitive and emotional functions, mood state, and sleep quality. In a randomised, placebo-controlled, parallel trial, fifty-nine mentally and physically healthy women aged 45–65 years received placebo (n 30) or the supplement (n 29) (both as 0·5 g twice per d) for 19 d. Emotional processing was significantly changed by supplementation, exhibiting a shift in bias away from negative stimuli. The results for the Affective Go/No-Go Task exhibited a slowing of responses to negative words, suggesting reduced attention to negative emotional stimuli. The results for the Facial Emotional Expression Rating Task also supported a shift away from attention to negative emotions and a bias towards happiness. An increase in arousal-like symptoms, labelled ‘high energy’, shorter reaction times and a slight benefit to sustained attention were observed in the treated subjects. Finally, when the supplement was taken 60–90 min before bedtime, a feeling of happiness before going to bed was consistently reported. In summary, daily consumption of a low-dose supplement containing bioavailable Trp may have beneficial effects on emotional and cognitive functions.
The Magellanic System represents one of the best places to study the formation and evolution of galaxies. Photometric surveys of various depths, areas and wavelengths have had a significant impact on our understanding of the system; however, a complete picture is still lacking. VMC (the VISTA near-infrared YJKs survey of the Magellanic System) will provide new data to derive the spatially resolved star formation history and to construct a three-dimensional map of the system. These data combined with those from other ongoing and planned surveys will give us an absolutely unique view of the system opening up the doors to truly new science!
We present a statistical analysis of the interactions between satellite galaxies in cosmological dark matter halos taken from fully self-consistent high-resolution simulations of galaxy clusters. We show that the number distribution of satellite encounters has a tail that extends to as many as three to four encounters per orbit. On average 30% of the substructure population had at least one encounter (per orbit) with another satellite galaxy. However, this result depends on the age of the dark matter host halo with a clear trend for more interactions in younger systems. We also report a correlation between the number of encounters and the distance of the satellites to the centre of the cluster — satellite galaxies closer to the centre experience more interactions. However, this can be simply explained by the radial distribution of the substructure population and merely reflects the fact that the density of satellites is higher in those regions.
In order to find substructure galaxies we applied (and present) a new technique based upon the N-body code MLAPM. This new halo finder MHF (MLAPM’s halo finder) acts with exactly the same accuracy as the N-body code itself and is therefore free of any bias and spurious mismatch between simulation data and halo finding precision related to numerical effects.
The Dominion Radio Astrophysical Observatory (DRAO) is carrying out a survey as part of an international collaboration to image the northe, at a common resolution, in emission from all major constituents of the interstellar medium; the neutral atomic gas, the molecular gas, the ionised gas, dust and relativistic plasma. For many of these constituents the angular resolution of the images (1 arcmin) will be more than a factor of 10 better than any previous studies. The aim is to produce a publicly-available database of high resolution, high-dynamic range images of the Galaxy for multi-phase studies of the physical states and processes in the interstellar medium. We will sketch the main scientific motivations as well as describe some preliminary results from the Canadian Galactic Plane Survey/Releve Canadien du Plan Galactique (CGPS/RCPG).
A survey of the Milky Way disk and the Magellanic System at the wavelengths of the 21-cm atomic hydrogen (H i) line and three 18-cm lines of the OH molecule will be carried out with the Australian Square Kilometre Array Pathfinder telescope. The survey will study the distribution of H i emission and absorption with unprecedented angular and velocity resolution, as well as molecular line thermal emission, absorption, and maser lines. The area to be covered includes the Galactic plane (|b| < 10°) at all declinations south of δ = +40°, spanning longitudes 167° through 360°to 79° at b = 0°, plus the entire area of the Magellanic Stream and Clouds, a total of 13 020 deg2. The brightness temperature sensitivity will be very good, typically σT≃ 1 K at resolution 30 arcsec and 1 km s−1. The survey has a wide spectrum of scientific goals, from studies of galaxy evolution to star formation, with particular contributions to understanding stellar wind kinematics, the thermal phases of the interstellar medium, the interaction between gas in the disk and halo, and the dynamical and thermal states of gas at various positions along the Magellanic Stream.
A study of selective area epitaxy (SAE) of GalnP lattice matched to GaAs is presented. The selectively regrown GaInP is used as the emitter of a novel heterojunction bipolar transistor (HBT) device structure. Successful SAE of GalnP on both dark field (mostly covered) and light field (mostly open) SiO2 masks is compared. To characterize the critical regrown heterojunction, diodes and HBTs were fabricated and measured. It is found that a pre-growth pause of either TEGa or PH3 results in forward bias characteristics with low leakage and an ideality factor of ~1.25, indicating low interfacial defect density. Non-self aligned regrown emitter HBTs grown with a dark field mask scheme have been fabricated. Devices with an emitter area of 3x12 μm exhibit small signal current gain up to 80 with an fT and fMAX of 22 GHz and 18 GHz, respectively. To further improve the performance of these devices, a structure with a self-aligned refractory metal base contact and light field regrowth is proposed.
Selective epitaxial growth (SEG) of silicon-germanium (SiGe) films on patterned-oxide silicon substrates, using a tubular hot-wall low pressure chemical vapor deposition (LPCVD) system, is demonstrated in this study. This conventional system is proposed as a low cost alternative for SiGe epitaxial growth. Three process improvements needed to achieve quality growth are discussed. First, the hydrogen bake process is modified to eliminate Ge-outgassing. Secondly, a Si SEG buffer layer is deposited prior to SiGe SEG. Finally, a small flow of dichlorosilane is introduced during the temperature ramp-down period prior to SiGe SEG. The growth results are discussed in terms of growth selectivity, thickness uniformity, growth rate, defect density, SiGe film composition, and electrical properties.
The use of thiourea/ammonia pre-treatments on (100) InP, followed by chemical bath deposition (CBD) of CdS thin films (∼ 30 Å), with low-temperature, low-pressure chemical vapor deposited SiO2 has been shown to produce metal-insulator-semiconductor (MIS) samples with near-ideal capacitance-voltage (C-V) response. Here, we report on x-ray photoelectron spectroscopy (XPS) analysis of the near-surface of InP following pre-treatment and CdS deposition. The pre-treatment was shown by XPS to form an indium sulfide layer and effectively remove native oxides from the InP surface. The subsequent deposition of CdS on a sulfur-passivated surface forms a stable layer which protects the substrate from oxidation during SiO2 chemical vapor deposition. MIS samples prepared using the pre-treatment without CdS deposition showed improved C- V response, while samples prepared with both the pre-treatment and CdS deposition showed a dramatic reduction in the density of interface states.
The General Insurance Board of the Faculty and Institute of Actuaries responded to some of the criticisms raised in the Morris review of the Actuarial Profession and in the press by rating agencies and others, regarding the Actuarial Profession's approach to actuarial reserving in general insurance by setting up a taskforce known as the General Insurance Reserving Issues Taskforce (GRIT). The taskforce worked from 2004 to 2006 and produced a significant report, including some new professional content and recommendations for further areas of development and research. Since then, through the GRIT successor body: the Reserving Oversight Committee (ROC), many working parties have formed and many General Insurance Research Organisation (GIRO) presentations and papers have been forthcoming. One area that has been a recurring theme through the last five years is how the Profession models and communicates the uncertainty in the claims reserving process. In the context of recent events in global financial markets, the forthcoming new regulatory framework of Solvency II, and the developments in other professions globally through IFRS and other drivers, it is timely that actuaries take stock of the many changes in our practices over the last five years and consider the direction actuaries should take for the challenges that lie ahead. This paper is a meta-study of the output of GRIT and ROC on reserving and uncertainty, with the intention of meeting these objectives.
Ionically self-assembled monolayer (ISAM) films have been shown to spontaneously produce noncentrosymmetric ordering that gives rise to a substantial second order nonlinear optical (NLO) response. Typically, the ISAM films for NLO response are an assemblage of bilayers of oppositely charged polymers whose thickness can be controlled through variation of pH and ionic strength of the immersion solutions. Here, we investigate the effects of replacing the NLO-active polymer layers with layers of monomeric chromophores containing ionic and covalent bonding sites. Films fabricated exclusively using polyelectrolytes contain some fraction of both randomly oriented and anti-parallel oriented chromophores. We have examined the incorporation of monomeric chromophores into ISAM films in order to increase the net polar orientation of the chromophores and reduce bilayer thickness.
Ion beam synthesis of a buried SiO2 layer is an attractive silicon-on-insulator technology for high speed CMOS circuits and radiation hardened devices. We demonstrate here a new annealing procedure at 1405°C that produces silicon films of excellent quality, essentially free of oxygen precipitates and with sharp interfaces between the Si and the SiO2.
The use of an AlGaAs/n-GaAs superlattice in place of the n-AlGaAs layer in MODFET devices reduces the light and temperature sensitivity of the threshold voltage. This paper considers the stability of Si doped superlattices under annealing conditions required for activation of the implant in the self-aligned gate MODFET fabrication process. Rapid optical annealing does not significantly degrade the superlattice structure. The DX center concentration in the superlattice structures is a factor of 30 less than measured in conventional MODFET structures. High performance MOOFET devices have been fabricated using the self-aligned gate process with rapid optical annealing.
Using high dose implantation of 200 keV Co ions followed by high temperature annealing, we have created buried layers of CoSi2 in crystalline Si of both (100) and (111) orientations. For a dose of 3 × 1017 Co/cm2, the layer that forms is ∼1100Å thick and the overlying Si is ∼600Å thick. A lower dose of 2 × 1017 Co/cm2 yields a thinner layer, 700Å thick, under 1200Å of crystalline Si. Rutherford Backscattering and channeling analysis of the layers shows that they are aligned with the substrate (χmin of the Co as low as 6.4%.) and TEM inspection of the (100) CoSi2/Si interfaces shows that they are abrupt and epitaxial (with occasional small facets). Moreover, electrical characterization of these layers yields resistance ratios that are better than epitaxial CoSi2 films grown by more conventional UHV methods.