Rotational Doppler beaming in eclipsing binaries

In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries with fast spinning components this photometric analogue of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf binary, a massive O-star binary and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in eclipsing systems is a prerequisite for deriving the correct stellar parameters from fitting high quality photometric light curves and can be used to determine stellar obliquities as well as e.g. an independent measure of the rotational velocity in those systems that may be expected to be fully synchronized.Comment: 5 pages, 3 figures, accepted by the Astrophysical Journal, Part

Is the American model Miss World? Choosing between the Anglo-Saxon model and a European-style alternative

In Lisbon, the European Union has set itself the goal to become the most competitive economy in the world in 2010 without harming social cohesion and the environment. The motivation for introducing this target is the substantially higher GDP per capita of US citizens. The difference in income is mainly a difference in the number of hours worked per employee. In terms of productivity per hour and employment per inhabitant, several European countries score equally well or even better than the United States, while at the same time they outperform the United States with a more equal distribution of income. The European social models are at least as interesting as the US model that is often considered a role model. In an empirical analysis for OECD countries, we aim to unravel 'the secret of success'. Our regression results show that income redistribution (through a social security system) does not necessarily lead to lower participation and higher unemployment, provided that countries supplement it with active labour market policies. Especially, spending on employment services like job-search assistance and vocational guidance, seems effective. Furthermore, the results suggest that generous unemployment benefits of short duration contribute to employment without widening the income distribution.

The mass of the neutron star in the low-mass X-ray binary 2A 1822-371

Using phase resolved spectroscopic observations obtained with the Ultraviolet and Visual Echelle Spectrograph on ESO's Kueyen Very Large Telescope supplemented by spectroscopic observations obtained with the Boller and Chivens Spectrograph on the Walter Baade Magellan telescope, we found sinusoidal radial-velocity variations with a semi-amplitude 327+-17 km/s. From previous observations and from the fact that the epoch of minimum velocity arrived early with respect to the epoch calculated from pulse timing we know that the companion star is suffering from irradiation. Since we most likely observed primarily the side of the companion star facing the observer at phase ~0.75 the velocity quoted above is not the true radial velocity semi-amplitude of the companion star. Assuming a uniform contribution to the line profile from this hemisphere yields a radial velocity semi-amplitude of 280+-26 km/s for a systemic velocity of 54+-24 km/s; if the contribution is instead weighted somewhat more towards the side of the companion facing the X-ray source then the true semi-amplitude is larger than this value. Together with the well constrained inclination (81<i<84 degrees) and the mass-function determined from pulse-timing analysis (2.03+-0.03 x 10^-2 Msun), we derive a lower limit to the mass of the neutron star and to that of the companion star of 0.97+-0.24 Msun and 0.33+-0.05 Msun, respectively (1 sigma; including uncertainties in the inclination). We briefly discuss other aspects of the spectrum and the implications of our findings.Comment: 6 pages, 2 figures, accepted for publication by MNRA

The eclipsing Cataclysmic Variable GS Pavonis: Evidence for disk radius changes

We have obtained differential time series photometry of the cataclysmic variable GS Pavonis over a timespan of 2 years. These show that this system is deeply eclipsing (~2-3.5 mag) with an orbital period of 3.72 hr. The eclipse depth and out-of-eclipse light levels are correlated. From this correlation we deduce that the disk radius is changing and that the eclipses in the low state are total. The derived distance to GS Pav is 790+/-90 pc, with a height above the galactic plane of 420+/-60 pc. We classify GS Pav as a novalike system.Comment: 4 pages, including 2 figures, accepted for publication in A&A Letter

Satellite shadows through stellar occultations

The impact of mega-constellations of satellites in low-Earth orbit during nighttime optical observations is assessed. Orbital geometry is used to calculate the impact of stellar occultations by satellites on the photometry of individual stars as well as the effect on the photometric calibration of wide-field observations. Starlink-type satellites will have occultation disks several arcseconds across. Together with occultation crossing times of 0.1-100 msec, this will lead to photometric `jitter' on the flux determination of stars. The level of impact for a given star depends on the ratio of the integration time of the frame over the occultation crossing time. In current-day, CCD-based synoptic surveys this impact is negligible (<<1%), but with future, CMOS-based wide-field surveys obtaining data at frequencies >1Hz, the impact will grow towards complete drop-outs. At integration times similar to the occultation crossing time, the orbit of a satellite can be traced using the occultation method. At even shorter integration times the shape of the occulting satellite can be deduced. Stellar occultations by passing satellites, enabled by high-speed CMOS technology, will be a new method to study orbiting satellites. Large scale monitoring programs will be needed to, independently, determine and update the orbits of satellites.Comment: 3 pages, 1 figure. Accepted to A&A, Sep 07 202

Tiling strategies for optical follow-up of gravitational wave triggers by wide field of view telescopes

Binary neutron stars are among the most promising candidates for joint gravitational-wave and electromagnetic astronomy. The goal of this work is to investigate the strategy of using gravitational wave sky-localizations for binary neutron star systems, to search for electromagnetic counterparts using wide field of view optical telescopes. We examine various strategies of scanning the gravitational wave sky-localizations on the mock 2015-16 gravitational-wave events. We propose an optimal tiling-strategy that would ensure the most economical coverage of the gravitational wave sky-localization, while keeping in mind the realistic constrains of transient optical astronomy. Our analysis reveals that the proposed tiling strategy improves the sky-localization coverage over naive contour-covering method. The improvement is more significant for observations conducted using larger field of view telescopes, or for observations conducted over smaller confidence interval of gravitational wave sky-localization probability distribution. Next, we investigate the performance of the tiling strategy for telescope arrays and compare their performance against monolithic giant field of view telescopes. We observed that distributing the field of view of the telescopes into arrays of multiple telescopes significantly improves the coverage efficiency by as much as 50% over a single large FOV telescope in 2016 localizations while scanning around 100 sq. degrees. Finally, we studied the ability of optical counterpart detection by various types of telescopes. In Our analysis for a range of wide field-of-view telescopes we found improvement in detection upon sacrificing coverage of localization in order to achieve greater observation depth for very large field-of-view - small aperture telescopes, especially if the intrinsic brightness of the optical counterparts are weak.Comment: Accepted for publication in A&A. 10 pages, 10 figure

Methods and systems for searching databases and displaying search results

In one aspect, the invention comprises a computer system comprising databases storing information regarding publications, the information comprising author, title, date of publication, abstract, cited references, and citing references data; and Internet servers in communication with the databases; wherein at least one of the Internet servers is in communication with and operable to transmit data to a Web browser application resident on a user's computer, and wherein the data is sufficient to enable the browser to display: (a) a search page for enabling the user to input publication search parameters; and (b) a results page comprising a tabular display of results that enables the user to sort results according to date, relevance, author, source title, and number of citations to each publication, and further comprising a list of publication titles, with each title having one or more adjacent selectable links to an aspect of the publication corresponding to the title

Hermetia illucens L. (Diptera, Stratiomyidae), nova tujerodna invazivna vrsta v Sloveniji

The black soldier fly (Hermetia illucens) was for the first time recorded in August 2009 for the territories of Slovenia. In 2010, the black soldier fly was found on several places in the coastal region of Primorska and in Ljubljana. The way of introduction and possible effects to other species are discussed.Muha vrste Hermetia illucens je bila na ozemlju Slovenije prvič najdena v avgustu l. 2009. Leta 2010 smo jo našli na več krajih obalnega dela Primorske in v Ljubljani. Razpravljava o načinu vnosa in možnih vplivih na druge vrste

Quantitative GPCR and ion channel transcriptomics in primary alveolar macrophages and macrophage surrogates

Background: Alveolar macrophages are one of the first lines of defence against invading pathogens and play a central role in modulating both the innate and acquired immune systems. By responding to endogenous stimuli within the lung, alveolar macrophages contribute towards the regulation of the local inflammatory microenvironment, the initiation of wound healing and the pathogenesis of viral and bacterial infections. Despite the availability of protocols for isolating primary alveolar macrophages from the lung these cells remain recalcitrant to expansion in-vitro and therefore surrogate cell types, such as monocyte derived macrophages and phorbol ester-differentiated cell lines (e.g. U937, THP-1, HL60) are frequently used to model macrophage function.Methods: The availability of high throughput gene expression technologies for accurate quantification of transcript levels enables the re-evaluation of these surrogate cell types for use as cellular models of the alveolar macrophage. Utilising high-throughput TaqMan arrays and focussing on dynamically regulated families of integral membrane proteins, we explore the similarities and differences in G-protein coupled receptor (GPCR) and ion channel expression in alveolar macrophages and their widely used surrogates.Results: The complete non-sensory GPCR and ion channel transcriptome is described for primary alveolar macrophages and macrophage surrogates. The expression of numerous GPCRs and ion channels whose expression were hitherto not described in human alveolar macrophages are compared across primary macrophages and commonly used macrophage cell models. Several membrane proteins known to have critical roles in regulating macrophage function, including CXCR6, CCR8 and TRPV4, were found to be highly expressed in macrophages but not expressed in PMA-differentiated surrogates.Conclusions: The data described in this report provides insight into the appropriate choice of cell models for investigating macrophage biology and highlights the importance of confirming experimental data in primary alveolar macrophages. © 2012 Groot-Kormelink et al.; licensee BioMed Central Ltd