A PRELIMINARY STUDY OF THE PALEOLITHIC AND NEOLITHIC CONTRIBUTION THE EUROPEAN MTDNA FLOW IN SHAPING THE GENETIC STRUCTURE OF RECENT BOSNIAN POPULATION

The mitochondrial DNA (mtDNA) polymorphisms in Bosnian human population was analyzed by means of hypervariable segment I and II (HVSI and HVSII) sequencing and restriction fragment-length polymorphism analysis of the mtDNA coding region. The results suggest that shaping the genetic structure of recent Bosnian population likely to be affected by the expansion from the European glacial refuges area at the end of the Last Glacial Maximum (LGM), postglacial expansions from southwestern refuges of Europe, the Italian Peninsula and the dispersion in periods of more recent historical events, from the East European Plain. Especially interesting feature of the Neolithic expansion in this area is the ancient African/South Asian haplogroup N1a with the HVSI variant 16147G, which is almost absent in Europe. The haplotyps HVSI with variant 16147G suggest the colonization of the Northeast Bosnia region by Neolithic communities in the Early Neolithic period of expansion through Europe, as evidenced by the archaeological remains of the Starcevo culture

A Comprehensive View of Circumstellar Disks in Chamaeleon I: Infrared Excess, Accretion Signatures and Binarity

We present a comprehensive study of disks around 81 young low-mass stars and brown dwarfs in the nearby ~2-Myr-old Chamaeleon I star-forming region. We use mid-infrared photometry from the Spitzer Space Telescope, supplemented by findings from ground-based high-resolution optical spectroscopy and adaptive optics imaging. We derive disk fractions of 52 (+/-6) % and 58 (+6/-7) % based on 8-micron and 24-micron colour excesses, respectively, consistent with those reported for other clusters of similar age. Within the uncertainties, the disk frequency in our sample of K3-M8 objects in Cha I does not depend on stellar mass. Diskless and disk-bearing objects have similar spatial distributions. There are no obvious transition disks in our sample, implying a rapid timescale for the inner disk clearing process; however, we find two objects with weak excess at 3-8 microns and substantial excess at 24 microns, which may indicate grain growth and dust settling in the inner disk. For a sub-sample of 35 objects with high-resolution spectra, we investigate the connection between accretion signatures and dusty disks: in the vast majority of cases (29/35) the two are well correlated, suggesting that, on average, the timescale for gas dissipation is similar to that for clearing the inner dust disk. The exceptions are six objects for which dust disks appear to persist even though accretion has ceased or dropped below measurable levels. Adaptive optics images of 65 of our targets reveal that 17 have companions at (projected) separations of 10-80 AU. Of the five <20 AU binaries, four lack infrared excess, possibly indicating that a close companion leads to faster disk dispersal. The closest binary with excess is separated by ~20 AU, which sets an upper limit of ~8 AU for the outer disk radius. (abridged)Comment: accepted for publication in the Astrophysical Journa

The influence of top managers' personal values on sustainability of SMEs in developing countries

The purpose of this paper is to provide a new theoretical insight regarding top managers' personal values in developing countries based on the Schwartz Values Theory (Schwartz, 1992, 1996, 2006; Schwartz and Bilsky, 1990) and to explore the influence of top managers' personal values on sustainability performances of successful businesses. The research describes personal values differences between top managers and their commitment to pro-social and pro-environmental responsibility who were approached through the validated and reliable questionnaire on identifying top managers' personal values (PVQ40) and questionnaire on sustainability indicators observed through the „triple bottom line“ concept which includes three measuring elements: financial, social and environmental performances (Fauzi, Svensson and Rahman, 2010). Given that top managers are very often the owners in SMEs, their values are largely reflected in the organizational values, which means that in small pro-environmentaly oriented firms, the personal values of ownersmanagers seem to play a much stronger part in motivating proenvironmental behaviors than in other SMEs (Lawrence at al., 2006). With regard to business sustainability, it is still insufficiently known, developed and understood in Southeast Europe and in developing countries. Therefore, this research may be used to encourage companies and local governments to include a sustainability issues in their business activities as a pre-condition for business success and competitiveness. The managers in SMEs can use this research as a guideline on introduction of contemporary principles of sustainability into their companies and to improve and direct their personal values towards sustainability.peer-reviewe

A Multiplicity Census of Young Stars in Chamaeleon I

We present the results of a multiplicity survey of 126 stars spanning ~0.1-3 solar masses in the ~2-Myr-old Chamaeleon I star-forming region, based on adaptive optics imaging with the ESO Very Large Telescope. Our observations have revealed 30 binaries and 6 triples, of which 19 and 4, respectively, are new discoveries. The overall multiplicity fraction we find for Cha I (~30%) is similar to those reported for other dispersed young associations, but significantly higher than seen in denser clusters and the field, for comparable samples. Both the frequency and the maximum separation of Cha I binaries decline with decreasing mass, while the mass ratios approach unity; conversely, tighter pairs are more likely to be equal mass. We confirm that brown dwarf companions to stars are rare, even at young ages at wide separations. Based on follow-up spectroscopy of two low-mass substellar companion candidates, we conclude that both are likely background stars. The overall multiplicity fraction in Cha I is in rough agreement with numerical simulations of cloud collapse and fragmentation, but its observed mass dependence is less steep than predicted. The paucity of higher-order multiples, in particular, provides a stringent constraint on the simulations, and seems to indicate a low level of turbulence in the prestellar cores in Cha I.Comment: Accepted for publication in Ap

AI-For-Mobility—A New Research Platform for AI-Based Control Methods

AI-For-Mobility (AFM) is the new research platform to investigate and implement novel control methods based on Artificial Intelligence (AI) within the Department of Vehicle System Dynamics at the German Aerospace Center (DLR). A production hybrid vehicle serves as a base platform. Since AI-based methods are data-driven, the vehicle is equipped with manifold sensors to provide the required data. They measure the vehicle’s state holistically and perceive the surrounding environment, while high performance on-board CPUs and GPUs handle the sensor data. A full by-wire control system enables the vehicle to be used for applications in the field of automated driving. Despite all modifications, it is approved for public road use and meets the driving dynamics properties of a standard road vehicle. This makes it an attractive research and test platform, both for automotive applications and technology demonstrations in other scientific fields (e.g., robotics, aviation, etc.). This paper presents the vehicle’s design and architecture in a detailed manner and shows a promising application potential of AFM in the context of AI-based control methods

Millimeter Imaging of the beta Pictoris Debris Disk: Evidence for a Planetesimal Belt

We present observations at 1.3 millimeters wavelength of the beta Pictoris debris disk with beam size 4.3 x 2.6 arcsec (83 x 50 AU) from the Submillimeter Array. The emission shows two peaks separated by ~7 arsec along the disk plane, which we interpret as a highly inclined dust ring or belt. A simple model constrains the belt center to 94+/-8 AU, close to the prominent break in slope of the optical scattered light. We identify this region as the location as the main reservoir of dust producing planetesimals in the disk.Comment: 9 pages, 2 figures, accepted by ApJ

Deep search for companions to probable young brown dwarfs

We have obtained high contrast images of four nearby, faint, and very low mass objects 2MASSJ04351455-1414468, SDSSJ044337.61+000205.1, 2MASSJ06085283-2753583 and 2MASSJ06524851-5741376 (here after 2MASS0435-14, SDSS0443+00, 2MASS0608-27 and 2MASS0652-57), identified in the field as probable isolated young brown dwarfs. Our goal was to search for binary companions down to the planetary mass regime. We used the NAOS-CONICA adaptive optics instrument (NACO) and its unique capability to sense the wavefront in the near-infrared to acquire sharp images of the four systems in Ks, with a field of view of 28"*28". Additional J and L' imaging and follow-up observations at a second epoch were obtained for 2MASS0652-57. With a typical contrast DKs= 4.0-7.0 mag, our observations are sensitive down to the planetary mass regime considering a minimum age of 10 to 120 Myr for these systems. No additional point sources are detected in the environment of 2MASS0435-14, SDSS0443+00 and 2MASS0608-27 between 0.1-12" (i.e about 2 to 250 AU at 20 pc). 2MASS0652-57 is resolved as a \sim230 mas binary. Follow-up observations reject a background contaminate, resolve the orbital motion of the pair, and confirm with high confidence that the system is physically bound. The J, Ks and L' photometry suggest a q\sim0.7-0.8 mass ratio binary with a probable semi-major axis of 5-6 AU. Among the four systems, 2MASS0652-57 is probably the less constrained in terms of age determination. Further analysis would be necessary to confirm its youth. It would then be interesting to determine its orbital and physical properties to derive the system's dynamical mass and to test evolutionary model predictions.Comment: Research note, 5 pages, 2 tables and 3 figures, accepted to A&

Diagnosing Circumstellar Debris Disks

(Abridged) A numerical model of a circumstellar debris disk is developed and applied to observations of the circumstellar dust orbiting beta Pictoris. The model accounts for the rates at which dust is produced by collisions among unseen planetesimals, and the rate at which dust grains are destroyed due to collisions. The model also accounts for the effects of radiation pressure, which is the dominant perturbation on the disk's smaller but abundant dust grains. Solving the resulting system of rate equations then provides the dust abundances versus grain size and over time. Those solutions also provide the dust grains' collisional lifetime versus grain size, and the debris disk's optical depth and surface brightness versus distance from the star. Comparison to observations then yields estimates of the unseen planetesimal disk's radius, and the rate at which the disk sheds mass due to planetesimal grinding. The model is then applied to optical observations of the edge-on dust disk orbiting beta Pictoris, and good agreement is achieved when the unseen planetesimal disk is broad, with 75<r<150 AU. If it is assumed that the dust grains are bright like Saturn's icy rings, then the cross section of dust in the disk is A_d~2x10^20 km^2 and its mass is M_d~11 lunar masses. In this case the planetesimal disk's dust production rate is quite heavy, dM_d/dt~9 earth-masses per Myr, implying that there is or was a substantial amount of planetesimal mass there, at least 110 earth-masses. But if the dust grains are darker than assumed, then the planetesimal disk's mass-loss rate and its total mass are heavier. In fact, the apparent dearth of any major planets in this region, plus the planetesimal disk's heavy mass-loss rate, suggests that the 75<r<150 AU zone at beta Pic might be a region of planetesimal destruction, rather than a site of ongoing planet formation.Comment: Accepted for publication in the Astrophysical Journa

A Keck LGS AO Search for Brown Dwarf and Planetary Mass Companions to Upper Scorpius Brown Dwarfs

We searched for binary companions to 20 young brown dwarfs in the Upper Scorpius association (145 pc, 5 Myr, nearest OB association) with the the Laser Guide Star adaptive optics system and the facility infrared camera NIRC2 on the 10 m Keck II telescope. We discovered a 0.14" companion (20.9+-0.4 AU) to the <0.1 MSun object SCH J16091837-20073523. From spectral deconvolution of integrated-light near-IR spectroscopy of SCH1609 using the SpeX spectrograph (Rayner et al. 2003), we estimate primary and secondary spectral types of M6+-0.5 and M7+-1.0, corresponding to masses of 79+-17 MJup and 55+-25 MJup at an age of 5 Myr and masses of 84+-15 MJup and 60+-25 MJup at an age of 10 Myr. For our survey objects with spectral types later than M8, we find an upper limit on the binary fraction of <9% (1-sigma) at separations of 10 -- 500 AU. We combine the results of our survey with previous surveys of Upper Sco and similar young regions to set the strongest constraints to date on binary fraction for young substellar objects and very low mass stars. The binary fraction for low mass (<40 MJup) brown dwarfs in Upper Sco is similar to that for T dwarfs in the field; for higher mass brown dwarfs and very low mass stars, there is an excess of medium-separation (10-50 AU projected separation) young binaries with respect to the field. These medium separation binaries will likely survive to late ages.Comment: 37 pages, 6 figures, accepted to Ap