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We present a detailed overview of the cosmological surveys that we aim to carry out with Phase 1 of the Square Kilometre Array (SKA1) and the science that they will enable. We highlight three main surveys: a medium-deep continuum weak lensing and low-redshift spectroscopic HI galaxy survey over 5 000 deg2; a wide and deep continuum galaxy and HI intensity mapping (IM) survey over 20 000 deg2 from
$z = 0.35$
to 3; and a deep, high-redshift HI IM survey over 100 deg2 from
$z = 3$
to 6. Taken together, these surveys will achieve an array of important scientific goals: measuring the equation of state of dark energy out to
$z \sim 3$
with percent-level precision measurements of the cosmic expansion rate; constraining possible deviations from General Relativity on cosmological scales by measuring the growth rate of structure through multiple independent methods; mapping the structure of the Universe on the largest accessible scales, thus constraining fundamental properties such as isotropy, homogeneity, and non-Gaussianity; and measuring the HI density and bias out to
$z = 6$
. These surveys will also provide highly complementary clustering and weak lensing measurements that have independent systematic uncertainties to those of optical and near-infrared (NIR) surveys like Euclid, LSST, and WFIRST leading to a multitude of synergies that can improve constraints significantly beyond what optical or radio surveys can achieve on their own. This document, the 2018 Red Book, provides reference technical specifications, cosmological parameter forecasts, and an overview of relevant systematic effects for the three key surveys and will be regularly updated by the Cosmology Science Working Group in the run up to start of operations and the Key Science Programme of SKA1.
Childhood maltreatment (CM) plays an important role in the development of major depressive disorder (MDD). The aim of this study was to examine whether CM severity and type are associated with MDD-related brain alterations, and how they interact with sex and age.
Within the ENIGMA-MDD network, severity and subtypes of CM using the Childhood Trauma Questionnaire were assessed and structural magnetic resonance imaging data from patients with MDD and healthy controls were analyzed in a mega-analysis comprising a total of 3872 participants aged between 13 and 89 years. Cortical thickness and surface area were extracted at each site using FreeSurfer.
CM severity was associated with reduced cortical thickness in the banks of the superior temporal sulcus and supramarginal gyrus as well as with reduced surface area of the middle temporal lobe. Participants reporting both childhood neglect and abuse had a lower cortical thickness in the inferior parietal lobe, middle temporal lobe, and precuneus compared to participants not exposed to CM. In males only, regardless of diagnosis, CM severity was associated with higher cortical thickness of the rostral anterior cingulate cortex. Finally, a significant interaction between CM and age in predicting thickness was seen across several prefrontal, temporal, and temporo-parietal regions.
Severity and type of CM may impact cortical thickness and surface area. Importantly, CM may influence age-dependent brain maturation, particularly in regions related to the default mode network, perception, and theory of mind.
We present a method for detecting parking spaces in radar images based on convolutional neural networks (CNN). A multiple-input multiple-output radar is used to render a slant-range image of the parking scenario and a background estimation technique is applied to reduce the impact of dynamic interference from the surroundings by separating the static background from moving objects in the scene. A CNN architecture, that also incorporates mechanisms to generalize the model to new scenarios, is proposed to determine the occupancy of the parking spaces in the static radar images. The experimental results show very high accuracy even in scenarios where little or no training data is available, proving the viability of the proposed approach for its implementation at large scale with reduced deployment efforts.
Some time ago, we reported the synthesis of bixbyite-type V2O3, a new metastable polymorph of vanadium sesquioxide. Since, a number of investigations followed, dealing with different aspects like electronic and magnetic properties of the material, the deviation from ideal stoichiometry or the preparation of nanocrystals as oxygen storage material. However, most of the physical properties were only evaluated on a theoretical basis. Here, we report the lattice dynamics and physical properties of bixbyite-type V2O3 bulk material, which we acquired from physical property measurements and neutron diffraction experiments over a wide temperature range. Besides attributing different possible orientations of the magnetic moments for V1 and V2 to the identified antiferromagnetic (AFM) ground state with a Néel temperature of 38.1(5) K, we use a first order Grüneisen approximation to determine lattice-dependent parameters for the relatively stiff cubic lattice, and, amongst others identify the Debye temperature to be as low as 350 ± 65 K.
The present contribution is a significant extension of the work by Kelbin et al. (J. Fluid Mech., vol. 721, 2013, pp. 340–366) as a new time-dependent helical coordinate system has been introduced. For this, Lie symmetry methods have been employed such that the spatial dependence of the originally three independent variables is reduced by one and the remaining variables are: the cylindrical radius
and the time-dependent helical variable
. The variables
are the usual cylindrical coordinates and
is an arbitrary function of time
, we retain the classical helically symmetric case. Using this, and imposing helical invariance onto the equation of motion, leads to a helically symmetric system of Euler and Navier–Stokes equations with a time-dependent pitch
, which may be varied arbitrarily and which is explicitly contained in all of the latter equations. This has been conducted both for primitive variables as well as for the vorticity formulation. Hence a significantly extended set of helically invariant flows may be considered, which may be altered by an external time-dependent strain along the axis of the helix. Finally, we sought new conservation laws which can be found from the helically invariant Euler and Navier–Stokes equations derived herein. Most of these new conservation laws are considerable extensions of existing conservation laws for helical flows at a constant pitch. Interestingly enough, certain classical conservation laws do not admit extensions in the new time-dependent coordinate system.
For a bivariate time series ((Xi ,Yi))i=1,...,n, we want to detect whether the correlation between Xi and Yi stays constant for all i = 1,...n. We propose a nonparametric change-point test statistic based on Kendall’s tau. The asymptotic distribution under the null hypothesis of no change follows from a new U-statistic invariance principle for dependent processes. Assuming a single change-point, we show that the location of the change-point is consistently estimated. Kendall’s tau possesses a high efficiency at the normal distribution, as compared to the normal maximum likelihood estimator, Pearson’s moment correlation. Contrary to Pearson’s correlation coefficient, it shows no loss in efficiency at heavy-tailed distributions, and is therefore particularly suited for financial data, where heavy tails are common. We assume the data ((Xi ,Yi))i=1,...,n to be stationary and P-near epoch dependent on an absolutely regular process. The P-near epoch dependence condition constitutes a generalization of the usually considered Lp-near epoch dependence allowing for arbitrarily heavy-tailed data. We investigate the test numerically, compare it to previous proposals, and illustrate its application with two real-life data examples.
We investigate the contribution of a local over- or under-density to linear estimates of the cosmic dipole. We focus on radio continuum surveys. Recently it was shown that the radio dipole amplitude is larger than expected from the corresponding dipole of the CMB. We show that a significant contribution to this excess could come from local structure.
Studying the amazingly diverse planet zoo provides us with unprecedented opportunities for understanding planet Earth and ultimately ourselves. An assessment of a planet's “habitability” reflects our Earth-centric prejudice and can serve to prioritise targets to actually search for signatures of life similar to ours. The probability for life beyond Earth to exist however remains unknown, and studies on habitability or statistics of planetary systems do not change this. But we can leave speculation behind, and embark on a journey of exploration. A sample of detected cosmic habitats would provide us with insight on the conditions for life to emerge, develop, and sustain, but disentangling the biota fraction from the duration of the biotic era would depend particularly on our knowledge about the dynamics of planetary systems. Apart from the fact that planets usually do not come alone, we also must not forget that the minor bodies in the Solar system vastly outnumber the planets. A focus on just what we might consider “habitable” planets is too narrow to understand their formation and evolution. While uniqueness prevents understanding, we need to investigate the context and embrace diversity. A comprehensive picture of planet populations can only arise by exploiting a variety of different detection techniques, where not only Kepler but also gravitational microlensing can now enter hitherto uncharted territory below the mass or size of the Earth. There is actually no shortage of planets, the Milky Way alone may host hundreds of billions, and so far we have found only about 1000.
We summarize the status of a computer simulator for microlens planet surveys. The simulator generates synthetic light curves of microlensing events observed with specified networks of telescopes over specified periods of time. Particular attention is paid to models for sky brightness and seeing, calibrated by fitting to data from the OGLE survey and RoboNet observations in 2011. Time intervals during which events are observable are identified by accounting for positions of the Sun and the Moon, and other restrictions on telescope pointing. Simulated observations are then generated for an algorithm that adjusts target priorities in real time with the aim of maximizing planet detection zone area summed over all the available events. The exoplanet detection capability of observations was compared for several telescopes.
Microlensing searches for planets are sensitive to small, cold exoplanets from 1–6 AU from their host stars and therefore probe an important part of parameter space. Other techniques would require many years of observations, often from space, to detect similar systems. Microlensing events can be characterised from only ground-based observations over a relatively short (≤100d) timescales. LCOGT and SUPA/St Andrews are building a robotic global network of telescopes that will be well suited to follow these events. Here we present preliminary results of the Galactic Bulge observing season 2010 March–October.
Members of the fungal genus Microbotryum are well-known parasites on eudicotyledonous plant hosts. However, recent studies focused exclusively on Microbotryum species being parasites in the anthers of Caryophyllaceae in which strong host-specificity was confirmed by molecular analyses. Consequently, species numbers have risen considerably as multi-host parasites were split up in so-called cryptic species. We subjected three non-caryophyllaceous Microbotryum groups to molecular phylogenetic analyses to see whether we would confirm multi-host morphospecies or if host-specific cryptic species in these selected groups could be revealed as well (i.e. a group of non-caryophyllaceous anther smuts, parasites on different Fallopia species, and parasites on Polygonum bistorta and Polygonum viviparum). We applied a multiple analysis strategy to correct for varying alignment effects on a two-locus dataset (ITS and LSU rDNA). The results obtained by the different approaches are uniform; high host-specificity exists in the non-caryophyllaceous anther smuts, but overlapping host ranges occur in the parasites of Fallopia species. Results for the parasites of Polygonum are similar, with Microbotryum bistortarum being separated into three lineages and M. marginale forming a lineage on P. bistorta which apparently is conspecific with M. bistortarum p.p. Our study shows that phylogenetic patterns within Microbotryum are much more complicated than deduced from morphological observations alone. Even though Microbotryum species are highly host-specific, it is impossible to identify species based solely on host taxa affiliation. Species status is reinstated for the anther smut on Salvia pratensis.
A study was conducted in healthy elderly living independently in senior housing to assess the impact of a probiotic yoghurt supplement on small intestinal bacterial overgrowth. Twenty-three participants with positive and thirteen participants with negative hydrogen breath test were studied before and after a period of 4 weeks of probiotic yoghurt administration. Intestinal permeability, plasma endotoxin levels, phagocytic activity of leucocytes, cytokine production by monocytes and free radical response of neutrophils were determined. Intestinal permeability was similar for the two groups and was unaffected by probiotic treatment. Both plasma endotoxin levels and the basal phagocytic activity of leucocytes decreased after yoghurt intake in the two groups. Exposure of monocytes and neutrophils ex vivo led to an increased cytokine response and free radical response, respectively. The normalisation of the various cytokine responses was more apparent in the group with positive breath test. In addition, the plasma levels of lipoplysaccharide binding protein and soluble CD14, lipoplysaccharide pattern recognition receptors and surrogate markers of lipoplysaccharide permeability were diminished by the end of the study. In conclusion, probiotic administration in the elderly normalises the response to endotoxin, and modulates activation markers in blood phagocytes, and therefore may help reduce low-grade chronic inflammation.
Gravitational microlensing observations will lead to a census of planets that orbit stars of different populations. From 2008, ARTEMiS will provide an expert system that allows to adopt a three-step strategy of survey, follow-up and anomaly monitoring of gravitational microlensing events that is capable of detecting planets of Earth mass and below. The SIGNALMEN anomaly detector, an integral part, has already demonstrated its performance during a pilot season. Embedded into eSTAR, ARTEMiS serves as an open platform that links with existing microlensing campaigns. Real-time visualization of ongoing events along with an interpretation moreover allows to communicate “Science live to your home” to the general public.
PLANET, the Probing Lensing Anomaly NETwork, is an international team
conducting observations of on-going gravitational microlensing
events from five sites in the southern hemisphere. Our primary goal is to
detect or to put constraints on sub-stellar companions of M dwarfs from the galactic disk.
We report the current status and discuss the future prospects.
A 2 m robotic telescope at Dome C which would benefit from continuous coverage and dream like seeing
(median of 0.27 arcsec) is currently the best option for a
ground based aggressive search for Earth-mass planets in the habitable zone.
Due to their extremely small luminosity compared to the stars they orbit, planets outside our own Solar System are extraordinarily difficult to detect directly in optical light. Careful photometric monitoring of distant stars, however, can reveal the presence of exoplanets via the microlensing or eclipsing effects they induce. The international PLANET collaboration is performing such monitoring using a cadre of semi-dedicated telescopes around the world. Their results constrain the number of gas giants orbiting 1–7 AU from the most typical stars in the Galaxy. Upgrades in the program are opening regions of “exoplanet discovery space” – toward smaller masses and larger orbital radii – that are inaccessible to the Doppler velocity technique.
We review the current status and future prospects of the PLANET collaboration, an international team of astronomers performing high-precision photometric monitoring of microlensing events. Our photometric precision and sampling is characterised and the suitability of the database for variable star studies is discussed. Preliminary results on K-giant stability are presented.
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