The latest on Apertif

We describe a Phased Array Feed (PAF) system, called Apertif, which will be installed in the Westerbork Synthesis Radio Telescope (WSRT). The aim of Apertif is, at frequencies from 1.0 to 1.7 GHz, to increase the instantaneous field of view of the WSRT 8 deg^2 and its observing bandwidth to 300 MHz with high spectral resolution. This system will turn the WSRT into an effective survey telescope with scientific applications ranging from deep surveys of the northern sky of HI and OH emission and polarised continuum to efficient searches for pulsars and transients. We present results obtained with a prototype PAF installed in one of the WSRT dishes. These results demonstrate that at decimetre wavelengths PAFs have excellent performance and that even for a single beam on the sky they outperform single feed radio dishes. PAFs turn radio telescopes into very effective survey instruments. Apertif is now fully funded and the community is invited to express their interest in using Apertif (http://www.astron.nl/radio-observatory/call-expressions-interest-apertif-surveys )Comment: Talk presented at 'A New Golden Age for Radio Astronomy', International SKA Forum 2010, 10-14 June 2010, Hof van Saksen, N

All-sky Radio SETI

Over the last decade, Aperture Arrays (AA) have successfully replaced parabolic dishes as the technology of choice at low radio frequencies - good examples are the MWA, LWA and LOFAR. Aperture Array based telescopes present several advantages, including sensitivity to the sky over a very wide field-of-view. As digital and data processing systems continue to advance, an all-sky capability is set to emerge, even at GHz frequencies. We argue that assuming SETI events are both rare and transitory in nature, an instrument with a large field-of-view, operating around the so-called water-hole (1-2 GHz), might offer several advantages over contemporary searches. Sir Arthur C. Clarke was the first to recognise the potential importance of an all-sky radio SETI capability, as presented in his book, Imperial Earth. As part of the global SKA (Square Kilometre Array) project, a Mid-Frequency Aperture Array (MFAA) prototype known as MANTIS (Mid- Frequency Aperture Array Transient and Intensity-Mapping System) is now being considered as a precursor for SKA-2. MANTIS can be seen as a first step towards an all-sky radio SETI capability at GHz frequencies. This development has the potential to transform the field of SETI research, in addition to several other scientific programmes.Comment: 7 pages, 4 figures, accepted for publication, Proceedings of Science, workshop on "MeerKAT Science: On the Pathway to the SKA", held in Stellenbosch 25-27 May 2016. Comments welcom

Reviewing global career dimensions: towards a future research model.

Considering the changing nature of the career concept, we conduct a review of both recent career theory and research findings on global managers' careers. Relying on recent career theory, we first identify different individual and organizational dimensions that are characteristic for contemporary careers. Guided by these career dimensions, we examine the research findings of expatriate studies to assess their meaningfulness for global careers. While this review confirms the dimensions as identified from career theory, it also suggests the relevance of an additional organizational career dimension and a new domain of cultural career dimensions. The result of both reviews is a research model that approaches global careers at the intersection of individual, organizational and cultural domains.Theory; Managers; Studies; Model;

Topographic hub maps of the human structural neocortical network

Hubs within the neocortical structural network determined by graph theoretical analysis play a crucial role in brain function. We mapped neocortical hubs topographically, using a sample population of 63 young adults. Subjects were imaged with high resolution structural and diffusion weighted magnetic resonance imaging techniques. Multiple network configurations were then constructed per subject, using random parcellations to define the nodes and using fibre tractography to determine the connectivity between the nodes. The networks were analysed with graph theoretical measures. Our results give reference maps of hub distribution measured with betweenness centrality and node degree. The loci of the hubs correspond with key areas from known overlapping cognitive networks. Several hubs were asymmetrically organized across hemispheres. Furthermore, females have hubs with higher betweenness centrality and males have hubs with higher node degree. Female networks have higher small-world indices

Політичні стереотипи та стереотипізація мислення: роль та значення у системі іміджевих комунікацій

Всебічно розглянуто особливості стереотипізації мислення як важливого чинника у процесі сприйняття та аналізу особою або групою осіб суспільно-політичної дійсності. Досліджено природу, джерела та механізми формування політичних стереотипів та показано їх роль і значення у системі іміджевих комунікацій. Наголошено на необхід- ності аналізу існуючої системи стереотипів при створенні іміджу суб’єкта політики.There have been thoroughly examined peculiarities of stereotyping of thinking as an important factor in the process of perception and analysis of socio-political reality by a person or a group of people. There have been investigated the nature, sources and mechanism of political stereotypes formation and showed their role and meaning in the system if image communications. There has been put an emphasis on the necessity of analysis of the existing system of stereotypes while creating the image of a subject of policy

Validation of NODDI estimation of dispersion anisotropy in V1 of the human neocortex

This work validates the estimation of neurite dispersion anisotropy in the brain, using Bingham-NODDI [1], an extension of the diffusion MRI technique called NODDI [2]. The original NODDI provides indices of neurite (axons and dendrites) morphology that are sensitive and specific to microstructural changes [3-7]. Bingham-NODDI additionally allows the estimation of neurite dispersion anisotropy, which can enhance the accuracy of tractography algorithms [8]. The in vivo feasibility of Bingham-NODDI has been evaluated in [1]. The present study validates its indices using high-resolution ex vivo imaging data of the human primary visual cortex (V1), a well characterised region of the neocortex known to include fibres that fan or bend into the cortical layers

Rates of carbonate cementation associated with sulphate reduction in DSDP/ODP sediments: implications for the formation of concretions

DSDP/ODP porewater profiles in organic carbon-bearing (<5% org. C) sediments commonly show decreases in Ca2+ concentrations and increases in alkalinity over depths where sulphate is being removed by microbial reduction. These Ca2+ depletion profiles represent the combined effect of diffusion, advection and reaction (addition by ion exchange and removal by precipitation mainly as CaCO3 and/or dolomite). A diagenetic model has been used to estimate the rate constant (k) for Ca2+ removal by precipitation during sulphate depletion over depths of 15-150 m, assuming first order kinetics. The rate constants for Ca2+ removal range from 10(-14) to 10(-11) s(-1) in 19 DSDP/ODP sediments, which span a range of bottom water temperatures (0-10 degreesC), lithologies (calcareous to clastic) and sedimentation rates (0.001-0.4 cm year(-1)). Values of k correlate with sedimentation rate (omega) such that log k=1.16 log omega-10.3, indicating that faster rates of Ca2+ removal occur at higher sedimentation rates where there are also higher degrees of saturation with respect to CaCO3 and dolomite. Depth-integrated masses of Ca2+ removed (<100 mumol cm(-2)) during sulphate depletion over these depth ranges are equivalent to a dispersed phase of approximately 1.5 wt.% CaCO3 or 3 wt.% dolomite in a compacted sediment. The complete occlusion of sediment porosity observed in concretions with isotopic signatures suggesting carbonate sourced from sulphate reduction therefore requires more time (a depositional hiatus), more rapid sulphate reduction (possibly by anaerobic methane oxidation) and/or the continued transport of isotopically light carbonate to the concretion site after sulphate reduction has ceased

Протоирей Сергий Булгаков в Крыму: жизнь, труды, изгнание

Silicon isotopes have considerable potential as proxy for (near-) surface processes and environmental conditions. However, unambiguous interpretations of isotope signatures in natural silica deposits are often hampered by a lack of independent quantitative information on isotopic fractionations operating under the environmental conditions of interest. We performed seeded silica precipitation experiments using flow-through reactors in the 10-60. °C temperature range to alleviate this problem. The principal objective was to quantify the silicon isotope fractionations during controlled precipitation of amorphous silica from a flowing aqueous solution. The experiments were designed to simulate silica deposition induced by a temperature drop, with particular relevance for (near-) surface hydrothermal systems associated with steep temperature gradients. Monitored differences in silicon isotope ratios