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Being a part of a social structure is key for survival and reproduction. Living with conspecifics boosts evolutionary fitness, by providing essential information about the environment. Nonetheless, studying neural mechanisms of social learning has not yet been established under laboratory conditions. To examine how socially passed information about the reward affects the behavior of individuals we used Eco-HAB, an automated system for tracing voluntary behavior of group-housed mice living under semi-naturalistic conditions. We show that a scent of a rewarded individual has profound effects on the conspecifics’ ability to find the reward in both familiar and novel environments. Importantly, the animals display clear and stable individual differences in social behavior. As a result, socially conveyed information has different effects on individual mice. Further, we show that disrupting neuronal plasticity in the prelimbic cortex with nanoparticles gradually releasing TIMP metallopeptidase inhibitor 1, disrupts animals’ social behavior and results in decreased ability to adapt to environmental changes. The experimental paradigm we developed can be further used to study neuronal mechanisms of social learning.

Breaking an impasse in finding mechanism-based therapies of neuropsychiatric disorders requires a strategic shift towards alleviating individual symptoms. Here we present a symptom and circuit-specific approach to rescue deficits of reward learning in Fmr1 knockout mice, a model of Fragile X syndrome (FXS), the most common monogenetic cause of inherited mental disability and autism. We use high-throughput, ecologically-relevant automated tests of cognition and social behavior to assess effectiveness of the circuit-targeted injections of designer nanoparticles, loaded with TIMP metalloproteinase inhibitor 1 protein (TIMP-1). Further, to investigate the impact of our therapeutic strategy on neuronal plasticity we perform long-term potentiation recordings and high-resolution electron microscopy. We show that central amygdala-targeted delivery of TIMP-1 designer nanoparticles reverses impaired cognition in Fmr1 knockouts, while having no impact on deficits of social behavior, hence corroborating symptom-specificity of the proposed approach. Moreover, we elucidate the neural correlates of the highly specific behavioral rescue by showing that the applied therapeutic intervention restores functional synaptic plasticity and ultrastructure of neurons in the central amygdala. Thus, we present a targeted, symptom-specific and mechanism-based strategy to remedy cognitive deficits in Fragile X syndrome.

Context. EE Cep is one of few eclipsing binary systems with a dark, dusty disk around an invisible object similar to {\epsilon} Aur. The system is characterized by grey and asymmetric eclipses every 5.6 yr, with a significant variation in their photometric depth, ranging from ~ 0 m .5 to ~ 2 m .0. Aims. The main aim of the observational campaign of the EE Cep eclipse in 2014 was to test the model of disk precession (Galan et al. 2012). We expected that this eclipse would be one of the deepest with a depth of ~ 2 m .0. Methods. We collected multicolor observations from almost 30 instruments located in Europe and North America. This photometric data covers 243 nights during and around the eclipse. We also analyse the low- and high-resolution spectra from several instruments. Results. The eclipse was shallow with a depth of 0 m .71 in V-band. The multicolor photometry illustrates small color changes during the eclipse with a total amplitude of order ~ +0 m . 15 in B-I color index. The linear ephemeris for this system is updated by including new times of minima, measured from the three most recent eclipses at epochs E = 9, 10 and 11. New spectroscopic observations were acquired, covering orbital phases around the eclipse, which were not observed in the past and increased the data sample, filling some gaps and giving a better insight into the evolution of the H {\alpha} and NaI spectral line profiles during the primary eclipse. Conclusions. The eclipse of EE Cep in 2014 was shallower than expected 0 m .71 instead of ~ 2 m . 0. This means that our model of disk precession needs revision., Comment: 10 pages, 13 figures, 29 tables in appendix, submited to Astronomy & Astrophysics

Populations of Bachman's Sparrows (Peucaea aestivalis) have declined range-wide since the late 1960s. Populations at the periphery of their range have exhibited some of the steepest declines, and these sparrows are now rare or extirpated over much of the northern extent of their historical range. To better understand the spatial ecology of Bachman's Sparrows in this region of decline, we examined microhabitat selection and determined the home range sizes of radio-tagged male Bachman's Sparrows (N = 37) in the Coastal Plain of North Carolina in 2014 and 2015. From April to July, we located males 1–2 times daily for 5–6 d per week. We measured vegetation structure in home ranges using 5-m-radius plots centered on a subset of 10 randomly selected telemetry locations as well as in available unused locations 50 m and in a random direction from each telemetry location. Mean size of home ranges (7.9 ha) was larger than estimates reported in most previous studies, with differences among studies possibly due, at least in part, to differences in the characteristics of habitats where studies were conducted. The home ranges of Bachman's Sparrows in our study had greater densities of woody and dead vegetation than unused areas. Although generally considered detrimental to the presence of Bachman's Sparrows, the presence of some woody vegetation in frequently burned (i.e., ≤ 3-yr return interval) longleaf pine (Pinus palustris) communities like those in our study may be important in providing song perches for males and cover from attacking predators. Bachman's Sparrows in our study showed clear selection for several vegetation characteristics linked to frequent fire. Management strategies that approximate historical fire regimes in longleaf pine ecosystems should continue to be promoted as essential tools for the conservation of Bachman's Sparrows.

Longleaf pine (Pinus palustris) ecosystems of the southeastern United States have experienced high rates of habitat loss and fragmentation, coinciding with dramatic population declines of a variety of taxa that inhabit the system. The Bachman's Sparrow (Peucaea aestivalis), a species closely associated with fire-maintained longleaf pine communities, is listed as a species of conservation concern across its entire range. Bachman's Sparrow breeding biology may provide valuable insights into population declines and inform restoration and management of remnant longleaf pine forest, but the species' secretive nesting habits have received little attention. We located 132 Bachman's Sparrow nests in the Coastal Plain and Sandhills physiographic regions of North Carolina, USA, during 2014–2015, and modeled nest-site selection and nest survival as a function of vegetation characteristics, burn history, temporal factors, and landscape-level habitat amount. There were distinct differences in nest-site select...

Context. We investigate small-amplitude light variations in FU Ori occurring in timescales of days and weeks. Aims. We seek to determine the mechanisms that lead to these light changes. Methods. The visual light curve of FU Ori gathered by the MOST satellite continuously for 55 days in the 2013-2014 winter season and simultaneously obtained ground-based multi-colour data were compared with the results from a disc and star light synthesis model. Results. Hotspots on the star are not responsible for the majority of observed light variations. Instead, we found that the long periodic family of 10.5-11.4 d (presumably) quasi-periods showing light variations up to 0.07 mag may arise owing to the rotational revolution of disc inhomogeneities located between 16-20 solar radii. The same distance is obtained by assuming that these light variations arise because of a purely Keplerian revolution of these inhomogeneities for a stellar mass of 0.7 solar mass. The short-periodic (3-1.38 d) small amplitude (0.01 mag) light variations show a clear sign of period shortening, similar to what was discovered in the first MOST observations of FU Ori. Our data indicate that these short-periodic oscillations may arise because of changing visibility of plasma tongues (not included in our model), revolving in the magnetospheric gap and/or likely related hotspots as well. Conclusions. Results obtained for the long-periodic 10-11 d family of light variations appear to be roughly in line with the colour-period relation, which assumes that longer periods are produced by more external and cooler parts of the disc. Coordinated observations in a broad spectral range are still necessary to fully understand the nature of the short-periodic 1-3 d family of light variations and their period changes., Accepted to A&A

Habitat loss and fragmentation are major threats to bird population persistence. Yet, our understanding of the demographic factors behind the adverse effects of fragmentation remains limited for many species. We studied the breeding demographics of the Bachman's Sparrow (Peucaea aestivalis), a species of conservation concern that is associated with highly imperiled longleaf pine ecosystems in the southeastern United States. We quantified the effects of local- and landscape-scale factors on different components of reproductive success (i.e., pairing success and probability of fledging offspring) for 96 male sparrows at eight sites in southeastern North Carolina. Pairing success of monitored sparrows was 69%, and 77% of paired males fledged ≥1 offspring. Habitat amount in the surrounding landscape, rather than local habitat quality, was the most influential predictor of pairing success for male Bachman's Sparrows. In contrast, we documented no predictors of successfully fledging offspring for paired males. We infer that reduced pairing success is limiting reproduction in isolated landscapes and may be a contributing factor for the low occupancy and declines of Bachman's Sparrow in our study region. Overall, our results suggest that managers can promote breeding opportunities for Bachman's Sparrows by prioritizing resources to patches near large, preexisting longleaf pine forest to ensure ≥20% habitat within the surrounding landscape.

Detection of periodicity in the broad-band non-thermal emission of blazars has so far been proven to be elusive. However, there are a number of scenarios which could lead to quasi-periodic variations in blazar light curves. For example, orbital or thermal/viscous period of accreting matter around central supermassive black holes could, in principle, be imprinted in the multi-wavelength emission of small-scale blazar jets, carrying as such crucial information about plasma conditions within the jet launching regions. In this paper, we present the results of our time series analysis of $\sim 9.2$ year-long, and exceptionally well-sampled optical light curve of the BL Lac OJ 287. The study primarily uses the data from our own observations performed at the Mt. Suhora and Krak\'ow Observatories in Poland, and at the Athens Observatory in Greece. Additionally, SMARTS observations were used to fill in some of the gaps in the data. The Lomb-Scargle Periodogram and the Weighted Wavelet Z-transform methods were employed to search for the possible QPOs in the resulting optical light curve of the source. Both the methods consistently yielded possible quasi-periodic signal around the periods of $\sim 400$ and $\sim 800$ days, the former one with a significance (over the underlying colored noise) of $\geq 99\%$. A number of likely explanations for such are discussed, with a preference given to a modulation of the jet production efficiency by highly magnetized accretion disks. This supports the previous findings and the interpretation reported recently in the literature for OJ 287 and other blazar sources., Comment: 7 pages, 5 figures, ApJ accepted

The detection of periodicity in the broadband non-thermal emission of blazars has so far been proven to be elusive. However, there are a number of scenarios that could lead to quasi-periodic variations in blazar light curves. For example, an orbital or thermal/viscous period of accreting matter around central supermassive black holes could, in principle, be imprinted in the multi-wavelength emission of small-scale blazar jets, carrying such crucial information about plasma conditions within the jet launching regions. In this paper, we present the results of our time series analysis of the ∼9.2 yr long, and exceptionally well-sampled, optical light curve of the BL Lac object OJ 287. The study primarily used the data from our own observations performed at the Mt. Suhora and Kraków Observatories in Poland, and at the Athens Observatory in Greece. Additionally, SMARTS observations were used to fill some of the gaps in the data. The Lomb-Scargle periodogram and the weighted wavelet Z-transform methods were employed to search for possible quasi-periodic oscillations in the resulting optical light curve of the source. Both methods consistently yielded a possible quasi-periodic signal around the periods of ∼400 and ∼800 days, the former with a significance (over the underlying colored noise) of . A number of likely explanations for this are discussed, with preference given to a modulation of the jet production efficiency by highly magnetized accretion disks. This supports previous findings and the interpretation reported recently in the literature for OJ 287 and other blazar sources. © 2016. The American Astronomical Society. All rights reserved.

PG 1351+489 is one of the 20 DBVs ― pulsating helium-atmosphere white dwarf stars ― known and has the simplest power spectrum for this class of star, making it a good candidate to study cooling rates. We report accurate period determinations for the main peak at 489.334 48 s and two other normal modes using data from the Whole Earth Telescope (WET) observations of 1995 and 2009. In 2009, we detected a new pulsation mode and the main pulsation mode exhibited substantial change in its amplitude compared to all previous observations. We were able to estimate the star's rotation period, of 8.9 h, and discuss a possible determination of the rate of period change of (2.0 ± 0.9) x 10 ―13 s s ―1 , the first such estimate for a DBV.

We present results of the modelling of multicolour light curves of 10 contact binary systems: V376 And, V523 Cas, CC Com, BX Dra, FG Hya, UZ Leo, XY Leo, AM Leo, EX Leo and RT LMi. The solutions resulted in a contact configuration for all systems. We found only FG Hya and UZ Leo to be in deep contact, the latter almost filling the outer critical lobe. The absolute parameters of the components have been determined with an accuracy of about a few per cent based on combined photometric and radial velocity curves, enlarging the sample of systems to 58 for which the physical parameters have been obtained in a uniform way. All but three systems (BX Dra, AM Leo and RT LMi) show asymmetries and peculiarities in the observed light curves, interpreted as resulting from their magnetic activity.

The blazar OJ 287 has produced two major optical outburst events during the years 2005-2008. These are the latest in a series of outbursts that have occurred repeatedly at 12 year intervals since early 1900s. It has been possible to explain the historical light curve fairly well by using a binary black hole model where the secondary black hole impacts the accretion disk of the primary twice during the 12 year orbital cycle. We will ask here how well does the latest light-curve fit with this model. We use a 10 million particle disk to model the accretion disk of the primary black hole. The rate of transfer of particles through the 10 Schwarzschild radius cylinder around the primary is followed. The secondary induces an inward flow through this surface. The inward flow rate is compared with the historical light curve as well as with the most recent observations reported in this paper. The observations have been carried out by using a number of small and medium size telescopes in different locations in order to ensure a dense light-curve coverage. The "inflow light curve" and the optical light curve of OJ 287 have a close resemblance to each other. It suggests that the tidally induced accretion flow is responsible for the main features of the optical light curve, with the exception of the quasi-periodic double peaks. It implies a close connection between the accretion disk and the jet where the optical synchrotron emission is presumably generated.

By using 78 newly determined timings of light minima together with those collected from the literature, we analysed the changes in the observed minus calculated (O-C) diagram in HS 0705+6700, a short-period (2.3 h) eclipsing binary that consists of a very hot subdwarf B-type (sdB) star and a very cool fully convective red dwarf. We confirmed the cyclic variation in the O-C and refined the parameters of the circumbinary brown dwarf (reported to orbit the binary system in 2009) by analysing the changes for the light travel time effect that arises from the gravitational influence of the third body. Our results indicate the lower mass limit of the third body to be M-3 sin i(') = 33.7(+/- 1.6) M-Jup. This companion would be a brown dwarf if its orbital inclination is larger than 27 degrees.7 and it is orbiting the central eclipsing binary with an eccentricity e similar to 0.2 at a separation of about 3.7(+/- 0.1) au.

We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain the nature of these flares. Precursor flare timings from the historical light curves are compared with theoretical predictions from our model that incorporate effects of an accretion disk and post-Newtonian description for the binary black hole orbit. We find that the precursor flares coincide with the secondary black hole descending toward the accretion disk of the primary black hole from the observed side, with a mean z-component of approximately zc = 4000 AU. We use this model of precursor flares to predict that precursor flare of similar nature should happen around 2020.96 before the next major outburst in 2022. © 2013. The American Astronomical Society. All rights reserved..

Context. Asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. These efforts already provided deep insight into physical properties of main-belt asteroids or large collisional families. Going into finer detail (e.g., smaller collisional families, asteroids with sizes 20 km) requires knowledge of physical parameters of more objects. Aims. We aim to increase the number of asteroid shape models and rotation states. Such results provide important input for further studies, such as analysis of asteroid physical properties in different populations, including smaller collisional families, thermophysical modeling, and scaling shape models by disk-resolved images, or stellar occultation data. This provides bulk density estimates in combination with known masses, but also constrains theoretical collisional and evolutional models of the solar system. Methods. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as input for the convex inversion method, and derive 3D shape models of asteroids together with their rotation periods and orientations of rotation axes. The key ingredient is the support of more that 100 observers who submit their optical data to publicly available databases. Results. We present updated shape models for 36 asteroids, for which mass estimates are currently available in the literature, or for which masses will most likely be determined from their gravitational influence on smaller bodies whose orbital deflections will be observed by the ESA Gaia astrometric mission. Moreover, we also present new shape model determinations for 250 asteroids, including 13 Hungarias and three near-Earth asteroids. The shape model revisions and determinations were enabled by using additional optical data from recent apparitions for shape optimization. © 2016 ESO., J.H. greatly appreciates the CNES post-doctoral fellowship program. J.H. and M.D. were supported by the project under the contract 11-BS56-008 (SHOCKS) of the French Agence National de la Recherche (ANR), JD by grant GACR 15-04816S of the Czech Science Foundation, DO by the grant NCN 2012/S/ST9/00022 of Polish National Science Center, and A. Marciniak by grant 2014/13/D/ST9/01818 of Polish National Science Center.

We report on analysis of 308.3 hrs of high speed photometry targeting the pulsating DA white dwarf EC14012-1446. The data were acquired with the Whole Earth Telescope (WET) during the 2008 international observing run XCOV26. The Fourier transform of the light curve contains 19 independent frequencies and numerous combination frequencies. The dominant peaks are 1633.907, 1887.404, and 2504.897 microHz. Our analysis of the combination amplitudes reveals that the parent frequencies are consistent with modes of spherical degree l=1. The combination amplitudes also provide m identifications for the largest amplitude parent frequencies. Our seismology analysis, which includes 2004--2007 archival data, confirms these identifications, provides constraints on additional frequencies, and finds an average period spacing of 41 s. Building on this foundation, we present nonlinear fits to high signal-to-noise light curves from the SOAR 4.1m, McDonald 2.1m, and KPNO 2m telescopes. The fits indicate a time-averaged convective response timescale of 99.4 +/- 17 s, a temperature exponent 85 +/- 6.2 and an inclination angle of 32.9 +/- 3.2 degrees. We present our current empirical map of the convective response timescale across the DA instability strip., Comment: Accepted for publication in the Astrophysical Journal

We present the results of the study of the contact binary system BO CVn. We have obtained physical parameters of the components based on combined analysis of new, multi-color light curves and spectroscopic mass ratio. This is the first time the latter has been determined for this object. We derived the contact configuration for the system with a very high filling factor of about 88 percent. We were able to reproduce the observed light curve, namely the flat bottom of the secondary minimum, only if a third light has been added into the list of free parameters. The resulting third light contribution is significant, about 20-24 percent, while the absolute parameters of components are: M1=1.16, M2=0.39, R1=1.62 and R2=1.00 (in solar units). The O-C diagram shows an upward parabola which, under the conservative mass transfer assumption, would correspond to a mass transfer rate of dM/dt = 6.3 \times 10-8M\odot/yr, matter being transferred from the less massive component to the more massive one. No cyclic, short-period variations have been found in the O-C diagram (but longer-term variations remain a possibility), 16 pages, 5 figures, 5 tables, accepted for publication by New Astronomy

Two observational campaigns were carried out during the eclipses of EE Cep in 2003 and 2008/9 to verify whether the eclipsing body in the system is indeed a dark disk and to understand the observed changes in the depth and durations of the eclipses. Multicolour photometric data and spectroscopic observations at both low and high resolution were collected. We numerically modelled the variations in brightness and colour during the eclipses. We tested models with different disk structure. We considered the possibility of disk precession. The complete set of observational data collected during the last three eclipses are made available to the astronomical community. Two blue maxima in the colour indices were detected during these two eclipses, one before and one after the photometric minimum. The first (stronger) blue maximum is simultaneous with a "bump" that is very clear in all the UBVRI light curves. Variations in the spectral line profiles seem to be recurrent during each cycle. NaI lines always show at least three absorption components during the eclipse minimum and strong absorption is superimposed on the H_alpha emission. These observations confirm that the eclipsing object in EE Cep system is indeed a dark, dusty disk around a low luminosity object. The primary appears to be a rapidly rotating Be star that is strongly darkened at the equator and brightened at the poles. Some of the conclusions of this work require verification in future studies: (i) a complex, possibly multi-ring structure of the disk in EE Cep; (ii) our explanation of the "bump" observed during the last two eclipses in terms of the different times of obscuration of the hot polar regions of the Be star by the disk; and (iii) our suggested period of the disk precession (~11-12 P_orb) and predicted depth of about 2 mag the forthcoming eclipse in 2014., Comment: 43 pages, 17 figures, accepted for publication in A&A

Context. EE Cep is an unusual long-period (5.6 yr) eclipsing binary discovered during the mid-twentieth century. It undergoes almost-grey eclipses that vary in terms of both depth and duration at different epochs. The system consists of a Be type star and a dark dusty disk around an invisible companion. EE Cep together with the widely studied ε Aur are the only two known cases of long-period eclipsing binaries with a dark, dusty disk component responsible for periodic obscurations. Aims. Two observational campaigns were carried out during the eclipses of EE Cep in 2003 and 2008/9 to verify whether the eclipsing body in the system is indeed a dark disk and to understand the observed changes in the depths and durations of the eclipses. Methods. Multicolour photometric data and spectroscopic observations performed at both low and high resolutions were collected with several dozen instruments located in Europe and North America. We numerically modelled the variations in brightness and colour during the eclipses. We tested models with different disk structure, taking into consideration the inhomogeneous surface brightness of the Be star. We considered the possibility of disk precession. Results. The complete set of observational data collected during the last three eclipses are made available to the astronomical community. The 2003 and 2008/9 eclipses of EE Cep were very shallow. The latter is the shallowest among all observed. The very high quality photometric data illustrate in detail the colour evolution during the eclipses for the first time. Two blue maxima in the colour indices were detected during these two eclipses, one before and one after the photometric minimum. The first (stronger) blue maximum is simultaneous with a "bump" that is very clear in all the UBV(RI)C light curves. A temporary increase in the I-band brightness at the orbital phase ∼0.2 was observed after each of the last three eclipses. Variations in the spectral line profiles seem to be recurrent during each cycle. The Na i lines always show at least three absorption components during the eclipse minimum and strong absorption is superimposed on the Hα emission. Conclusions. These observations confirm that the eclipsing object in EE Cep system is indeed a dark, dusty disk around a low luminosity object. The primary appears to be a rapidly rotating Be star that is strongly darkened at the equator and brightened at the poles. Some of the conclusions of this work require verification in future studies: (i) a complex, possibly multi-ring structure of the disk in EE Cep; (ii) our explanation of the "bump" observed during the last two eclipses in terms of the different times of obscuration of the hot polar regions of the Be star by the disk; and (iii) our suggested period of the disk precession (∼11-12 Porb) and predicted depth of about 2m ̇ for the forthcoming eclipse in 2014. © 2012 ESO.

We have analyzed the available spectra of WW And and for the first time obtained a reasonably well defined radial velocity curve of the primary star. Combined with the available radial velocity curve of the secondary component, these data led to the first determination of the spectroscopic mass ratio of the system at q-spec = 0.16 +/- 0.03. We also determined the radius of the accretion disc from analysis of the double-peaked H-alpha emission lines. Our new, high-precision, Johnson VRI and the previously available Stromgren vby light curves were modelled with stellar and accretion disc models. A consistent model for WW And - a semidetached system harbouring an accretion disc which is optically thick in its inner region, but optically thin in the outer parts - agrees well with both spectroscopic and photometric data., Comment: Accepted by New Astronomy

The results of photoelectric photometry with the narrowband CN, C 3 , C 2 , blue continuum, and ultraviolet continuum IHW interference filters are presented. The observations were carried out with a set of diaphragms of different radii. Vectorial Monte Carlo modeling of the cometary coma was used for the determination of production rates of the radicals, the parent and daughter lifetimes, and the daugher ejection velocities from the parents. The CN and C 2 parent lifetimes (at 1.0 AU) were 2.7 ± 1.3 × 10 4 and 2.3 ± 0.6 × 10 4 sec, respectively, and the lifetimes of CN, C 3 , and C 2 molecules were 2.1 ± 3.0 × 10 5 , 1.8 ± 2.0 × 10 5 , and 1.1 ± 0.4 × 10 5 sec (at 1.0 AU), respectively. The daughter ejection velocities from parents were 2.6 ± 1.2 km sec -1 for the CN and 0.1 ± 0.8 km sec -1 for the C 2 molecule. The dependence on heliocentric distance of the molecules and dust production rates in the range of 0.7 ÷ 1.0 AU was described by the power law function r -n h . The power index was 2.97 ± 0.11 for CN, 2.34 ± 0.55 for C 3 , 2.44 ± 0.17 for C 2 , and 3.44 ± 0.51 for dust. Relative abundances of CN and C 3 for Comet Austin at 1.0 AU postperihelion were similar to the "normal" ones with some enrichment of the C 2 molecule.

This paper presents the absolute parameters of RZ Dra. New CCD observations were made at the Mt. Suhora Observatory in 2007. Two photometric data sets (1990 BV and 2007 BVRI) were analysed using modern light-curve synthesis methods. Large asymmetries in the light curves may be explained in terms of a dark starspot on the primary component, an A6 type star. Due to this magnetic activity, the primary component would appear to belong to the class of Ap-stars and would show small amplitude with δ Scuti-type pulsations. With this in mind, a time-series analysis of the residual light curves was made. However, we found no evidence of pulsation behaviour in RZ Dra. Combining the solutions of our light curves and Rucinski et al. (2000) ’s radial velocity curves, the following absolute parameters of the components were determined: M1 = 1.63 ± 0.03 M⊙, M2 = 0.70 ± 0.02 M⊙, R1 = 1.65 ± 0.02R⊙, R2 = 1.15 ± 0.02 R⊙, L1 = 9.72 ± 0.30 L⊙ and L2 = 0.74 ± 0.10 L⊙. The distance to RZ Dra was calculated as 400 ± 25 pc, taking into account interstellar extinction. The orbital period of the system was studied using updated O–C information. It was found that the orbital period varied in its long-period sinusoidal form, superimposed on a downward parabola. The parabolic term shows a secular period decrease at a slow rate of 0.06 ± 0.02 s per century and is explained by the mass loss via magnetized wind of the Ap-star primary. The tilted sinusoidal form of the period variation may be considered as an apparent change and may be interpreted in terms of the light-time effect due to the presence of a third body.

We constrain the distribution of calcium across the surface of the white dwarf star G29-38 by combining time series spectroscopy from Gemini-North with global time series photometry from the Whole Earth Telescope. G29-38 is actively accreting metals from a known debris disk. Since the metals sink significantly faster than they mix across the surface, any inhomogeneity in the accretion process will appear as an inhomogeneity of the metals on the surface of the star. We measure the flux amplitudes and the calcium equivalent width amplitudes for two large pulsations excited on G29-38 in 2008. The ratio of these amplitudes best fits a model for polar accretion of calcium and rules out equatorial accretion., Comment: Accepted to the Astrophysical Journal. 16 pages, 10 figures.

OJ 287 is a BL Lac object at redshift.z= 0.306 that has shown double-peaked bursts at regular intervals of ∼12 yr during the last ∼40 yr. We analyse optical photopolarimetric monitoring data from 2005 to 2009, during which the latest double-peaked outburst occurred. The aim of this study is twofold: firstly, we aim to analyse variability patterns and statistical properties of the optical polarization light curve. We find a strong preferred position angle in optical polarization. The preferred position angle can be explained by separating the jet emission into two components: an optical polarization core and chaotic jet emission. The optical polarization core is stable on time-scales of years and can be explained as emission from an underlying quiescent jet component. The chaotic jet emission sometimes exhibits a circular movement in the Stokes plane. We find six such events, all on the time-scales of 10-20 d. We interpret these events as a shock front moving forwards and backwards in the jet, swiping through a helical magnetic field. Secondly, we use our data to assess different binary black hole models proposed to explain the regularly appearing double-peaked bursts in OJ 287. We compose a list of requirements a model has to fulfil to explain the mysterious behaviour observed in OJ 287. The list includes not only characteristics of the light curve but also other properties of OJ 287, such as the black hole mass and restrictions on accretion flow properties. We rate all existing models using this list and conclude that none of the models is able to explain all observations. We discuss possible new explanations and propose a new approach to understanding OJ 287. We suggest that both the double-peaked bursts and the evolution of the optical polarization position angle could be explained as a sign of resonant accretion of magnetic field lines, a 'magnetic breathing' of the disc. © 2010 The Authors. Journal compilation © 2010 RAS.

To understand the properties of orbital period changes of four short period sdB-type eclipsing binaries, HW Vir, HS 0705 + 6700, HS 2231 + 2441, and NSVS 14256825, we have monitored them photometrically since 2006. Apart from HW Vir, it is found that the O-C diagrams of HS 0705 + 6700 and HS 2231 + 2441 can also be described by a cyclic variation superimposed on a downward parabolic curve, indicating a long-term period decrease in the two systems. Therefore, of the four binary systems, long-term period variations have been detected for three ones that can be explained by magnetic braking of the fully convective component stars. This may drive these systems to evolution into normal cataclysmic variables. As for the cyclic period variations observed in the four systems, the light-travel time effect via the presence of a tertiary component is the most possible mechanism to interpret the periodic change, which reveals the presence of extremely low-mass objects (e.g., brown dwarf stars and huge planets) in this kind of binaries.

The results of the photoelectric photometry with the narrowband CN, C3, C2 and Blue Continuum (BC) IHW interference filters are presented. Observations were carried out with a set of diaphragms of different effective radii. On the base of the Haser model the production rates of the radicals have been obtained. The CN and C2 molecules scale lengths (3.4 × 105 km and 8.5 × 104 km respectively for 1.0 AU heliocentric distance) have been also derived. The dust continuum spectrum is negligibly low in comparison with the molecular one, which stay in agreement with the results of other observations of comet Okazaki-Levy-Rudenko.

HS 0705+6700 is a short-period (P=2.3 hours), close binary containing a hot sdB-type primary and a fully convective secondary. We have monitored this eclipsing binary for more than 2 years and as a result, 32 times of light minimum were obtained. Based on our new eclipse times together with these compiled from the literature, it is discovered that the O-C curve of HS 0705+6700 shows a cyclic variation with a period of 7.15 years and a semiamplitude of 92.4 s. The periodic change was analyzed for the light-travel time effect that may be due to the presence of a tertiary companion. The mass of the third body is determined to be M3 sin i = 0.0377 (+/-0.0043) Msun when a total mass of 0.617 Msun for HS 0705+6700 is adopted. For orbital inclinations i >= 32.8, the mass of the tertiary component would be below the stable hydrogen-burning limit of M3~0.072 Msun, and thus it would be a brown dwarf. The third body is orbiting the sdB-type binary at a distance shorter than 3.6 astronomical units (AU). HS 0705+6700 was formed through the evolution of a common envelope after the primary becomes a red giant. The detection of a sub-stellar companion in HS 0705+6700 system at this distance from the binary could give some constraints on stellar evolution in such systems and the interactions between red giants and their companions., 10 pages, 3 figures To be published in Astrophysical Journal

The blazar OJ 287 has produced two major optical outburst events during the years 2005-2008. These are the latest in a series of outbursts that have occurred repeatedly at 12 year intervals since early 1900s. It has been possible to explain the historical light curve fairly well by using a binary black hole model where the secondary black hole impacts the accretion disk of the primary twice during the 12 year orbital cycle. We will ask here how well does the latest light-curve fit with this model. We use a 10 million particle disk to model the accretion disk of the primary black hole. The rate of transfer of particles through the 10 Schwarzschild radius cylinder around the primary is followed. The secondary induces an inward flow through this surface. The inward flow rate is compared with the historical light curve as well as with the most recent observations reported in this paper. The observations have been carried out by using a number of small and medium size telescopes in different locations in order to ensure a dense light-curve coverage. The "inflow light curve" and the optical light curve of OJ 287 have a close resemblance to each other. It suggests that the tidally induced accretion flow is responsible for the main features of the optical light curve, with the exception of the quasi-periodic double peaks. It implies a close connection between the accretion disk and the jet where the optical synchrotron emission is presumably generated. © 2009. The American Astronomical Society. All rights reserved..

EC14012-1446 is a hydrogen atmosphere (DA) white dwarf pulsator. Its rich pulsation spectrum displays a range of excited modes with complex multiplet structure, in addition to numerous combination frequencies. In April 2008, EC14012-1446 was the primary target of XCOV26. We obtained over 300 hrs of nearly continuous high speed photometry with the goal of using the nonlinear pulse shapes to empirically determine the parameters of the convection zone. The Fourier transform (FT) of the light curve contains power between 1000 to 4000 μHz, with the dominant peak at 1234 μHz. We find 13 independent frequencies distributed in 8 modes, as well as a myriad of combination frequencies. In the following, we present preliminary results and lay the groundwork for future investigation leading to light curve fitting of EC14012-1446.

(Abridged) OJ287 is a BL Lac object that has shown double-peaked bursts at regular intervals of ~12 yr during the last ~40 yr. We analyse optical photopolarimetric monitoring data from 2005-2009, during which the latest double-peaked outburst occurred. The aim of this study is twofold: firstly, we aim to analyse variability patterns and statistical properties of the optical polarization light-curve. We find a strong preferred position angle in optical polarization. The preferred position angle can be explained by separating the jet emission into two components: an optical polarization core and chaotic jet emission. The optical polarization core is stable on time scales of years and can be explained as emission from an underlying quiescent jet component. The chaotic jet emission sometimes exhibits a circular movement in the Stokes plane. We interpret these events as a shock front moving forwards and backwards in the jet, swiping through a helical magnetic field. Secondly, we use our data to assess different binary black hole models proposed to explain the regularly appearing double-peaked bursts in OJ287. We compose a list of requirements a model has to fulfil. The list includes not only characteristics of the light-curve but also other properties of OJ287, such as the black hole mass and restrictions on accretion flow properties. We rate all existing models using this list and conclude that none of the models is able to explain all observations. We discuss possible new explanations and propose a new approach to understanding OJ287. We suggest that both the double-peaked bursts and the evolution of the optical polarization position angle could be explained as a sign of resonant accretion of magnetic field lines, a 'magnetic breathing' of the disc., Comment: Accepted for publication in MNRAS (26 pages, 24 figures, 4 tables)

Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ287. This quasar shows quasi-periodic optical outbursts at 12 yr intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened twenty days later., Comment: 14 pages, 3 figures, published in Nature

Opinions about early endoscopic sphincterotomy and time of laparoscopic cholecystectomy in acute biliary pancreatitis are still controversial. Some authors reserved this procedure only for cases in which the stones were visualized during ERCP or patients had clinical symptoms of acute cholangitis. The aim was the assessment of the dynamic of changes of proinflammatory cytokines and white blood cells in time in patients with acute biliary pancreatitis after performed endoscopic sphincterotomy and laparoscopic cholecystectomy.We enrolled 43 consecutive patients with clinically diagnosed mild forms of acute biliary pancreatitis. All were treated by early endoscopic sphincterotomy and laparoscopic cholecystectomy performed during the first 48 hours after admission. The course of the disease was monitored by measurement of the level of proinflammatory cytokines.Marked decrease of the level of proinflammatory interleukins within 24 hours after endoscopic sphincterotomy was observed. Mean values of IL-6 and IL-8 were statistically lower immidiately after this procedure (p0.001). Subsequent decrease was achieved after laparoscopic cholecystectomy. The mean values of TNF-alpha and IL-12p40 were relatively constant throughout the study period.All patients suffering from mild acute biliary pancreatitis should be treated by using minimally invasive procedures. However, such a only treatment should be reserved for experienced centers.

The results of the multiaperture photometry of Comet Shoemaker–Levy 1991 T2 in the pre-perihelion and P/deVico in the post-perihelion period with the narrowband CN, C2 and Blue Continuum (BC) IHW filters are presented. A Haser model of the molecular coma was used for the determination of the parent and daughter scale-lengths and production rates of the radicals. The comets showed some substantial differences between their parent scale-lengths. The CN parent scale-length (at 1.0 AU) was 16 × 10 3 km for Comet Shoemaker–Levy and 39 × 10 3 for P/deVico, the C2 parent scale-lengths were respectively 29 × 10 3 and 54 × 10 3 km . Such divergences could be interpreted in the frame of different scenarios of emission of cometary parents, either from a nucleus or from a volume source. The daughter scale-lengths for these comets were quite similar, namely: 306 × 10 3 and 318 × 10 3 km for CN and 69 × 10 3 and 66 × 10 3 km for C2. We determined the Afρ parameter for apertures of different radii. A Monte Carlo model of the dust coma was used to obtain the dust ejection velocity. It was of the order of 0.1 km s−1 for both comets. The power index of the distribution of the β-parameter of dust particles (ratio of light pressure to the solar gravitation) was of the order of 3 for C/Shoemaker–Levy and close to 2 for P/deVico. The dependence on heliocentric distance ( r h ) of the radical and dust production rates for P/deVico in the range of 0.7–1.0 AU was described by the power law function r h − α with a power index equal to: 5.55 ± 0.14 for CN, 5.70 ± 0.24 for C2 and 5.22 ± 0.19 for dust. Relative abundances of the dynamically new Comet Shoemaker–Levy and short-period P/deVico were quite similar with an enhancement of C2 comparing with standard values taken from A'Hearn et al. (1995).

We report multicolour photometric observations of the 2003 eclipse of the long-period (5.6 yr) eclipsing binary EE Cep. Measurements were obtained with ten telescopes at eight observatories in four countries. In most cases, UBV(RI)C broad band filters have been used. The light curve shape shows that the obscuring body is an almost dark disk around a low-luminosity central object. However, variations of the colour indices during the eclipse indicate that the obscuring body emits a considerable amount of radiation in the near infrared.

We report multicolour photometric observations of the 2003 eclipse of the long-period (5.6 yr) eclipsing binary EE Cep. Measurements were obtained with ten telescopes at eight observatories in four countries. In most cases, UBV(RI)C broad band filters have been used. The light curve shape shows that the obscuring body is an almost dark disk around a low-luminosity central object. However, variations of the colour indices during the eclipse indicate that the obscuring body emits a considerable amount of radiation in the near infrared. © Springer 2005.

This paper presents the results of the analysis of (O-C) diagrams of four eclipsing variables. The diagrams are based on times of minima collected in the Cracow database, which contains times of minima found in the literature, from observations at Mt. Suhora and Ulupinar Observatories, or determined using publicly-available photometric surveys (NSVS, ASAS etc).

We report two cases of primary peritoneal mesothelioma. In both of them contact with asbestos was negative. In the first case the patient was hospitalized in another hospital five years earlier. The performed USG and CT of the abdomen revealed the tumor near the spleen. But then the patient was not operated. In the second case the symptoms lasted for several months. In both cases the tumors were nonoperative because of the advanced malignant process.

The serum iron level drops in many diseases and after bone fractures or elective surgical operations. The aim of this study was to determine if the degree of stress hypoferremia depends on severity of the operation. Serum iron concentration and TIBC was measured during two weeks in 37 patients. The first group consisted of 29 patients operated for ingunal hernia or cholelithiasis. It was laparoscopic cholecystectomy or classical or laparoscopic hernia repair. These types of operations were considered as mild surgical stress. The second group consisted of 8 patients with colon cancer, who had segmental colon resection. This operation was considered as severe surgical stress. The patients with colon cancer had significantly lower preoperative serum iron level. After operations, profound but temporal drop in serum iron concentration was observed in both groups of patients. TIBC drops but not so significantly. The diagrams illustrating changes of iron concentration after operations looked similar in both groups.The changes of iron concentration after abdominal operations are independent of the severity of surgical stress.