412 research outputs found
The Missing Link of Jewish European Ancestry: Contrasting the Rhineland and the Khazarian Hypotheses
The question of Jewish ancestry has been the subject of controversy for over
two centuries and has yet to be resolved. The "Rhineland Hypothesis" proposes
that Eastern European Jews emerged from a small group of German Jews who
migrated eastward and expanded rapidly. Alternatively, the "Khazarian
Hypothesis" suggests that Eastern European descended from Judean tribes who
joined the Khazars, an amalgam of Turkic clans that settled the Caucasus in the
early centuries CE and converted to Judaism in the 8th century. The Judaized
Empire was continuously reinforced with Mesopotamian and Greco-Roman Jews until
the 13th century. Following the collapse of their empire, the Judeo-Khazars
fled to Eastern Europe. The rise of European Jewry is therefore explained by
the contribution of the Judeo-Khazars. Thus far, however, their contribution
has been estimated only empirically; the absence of genome-wide data from
Caucasus populations precluded testing the Khazarian Hypothesis. Recent
sequencing of modern Caucasus populations prompted us to revisit the Khazarian
Hypothesis and compare it with the Rhineland Hypothesis. We applied a wide
range of population genetic analyses - including principal component,
biogeographical origin, admixture, identity by descent, allele sharing
distance, and uniparental analyses - to compare these two hypotheses. Our
findings support the Khazarian Hypothesis and portray the European Jewish
genome as a mosaic of Caucasus, European, and Semitic ancestries, thereby
consolidating previous contradictory reports of Jewish ancestry.Comment: 21 pages, 7 figures, 1 table, 7 supplementary figures, 7
supplementary table
The evolution of substructure II: linking dynamics to environment
We present results from a series of high-resolution N-body simulations that
focus on the formation and evolution of eight dark matter halos, each of order
a million particles within the virial radius. We follow the time evolution of
hundreds of satellite galaxies with unprecedented time resolution, relating
their physical properties to the differing halo environmental conditions. The
self-consistent cosmological framework in which our analysis was undertaken
allows us to explore satellite disruption within live host potentials, a
natural complement to earlier work conducted within static potentials. Our host
halos were chosen to sample a variety of formation histories, ages, and
triaxialities; despite their obvious differences, we find striking similarities
within the associated substructure populations. Namely, all satellite orbits
follow nearly the same eccentricity distribution with a correlation between
eccentricity and pericentre. We also find that the destruction rate of the
substructure population is nearly independent of the mass, age, and triaxiality
of the host halo. There are, however, subtle differences in the velocity
anisotropy of the satellite distribution. We find that the local velocity bias
at all radii is greater than unity for all halos and this increases as we move
closer to the halo centre, where it varies from 1.1 to 1.4. For the global
velocity bias we find a small but slightly positive bias, although when we
restrict the global velocity bias calculation to satellites that have had at
least one orbit, the bias is essentially removed.Comment: 14 pages, 14 figures, MNRAS in pres
Die Diskrepanz zwischen historischer Zufälligkeit und normativem Charakter des neutestamentlichen Kanons als hermeneutisches Problem
Multi-Messenger Astronomy with Extremely Large Telescopes
The field of time-domain astrophysics has entered the era of Multi-messenger
Astronomy (MMA). One key science goal for the next decade (and beyond) will be
to characterize gravitational wave (GW) and neutrino sources using the next
generation of Extremely Large Telescopes (ELTs). These studies will have a
broad impact across astrophysics, informing our knowledge of the production and
enrichment history of the heaviest chemical elements, constrain the dense
matter equation of state, provide independent constraints on cosmology,
increase our understanding of particle acceleration in shocks and jets, and
study the lives of black holes in the universe. Future GW detectors will
greatly improve their sensitivity during the coming decade, as will
near-infrared telescopes capable of independently finding kilonovae from
neutron star mergers. However, the electromagnetic counterparts to
high-frequency (LIGO/Virgo band) GW sources will be distant and faint and thus
demand ELT capabilities for characterization. ELTs will be important and
necessary contributors to an advanced and complete multi-messenger network.Comment: White paper submitted to the Astro2020 Decadal Surve
Agent-based models predict patterns and identify constraints of large carnivore recolonizations, a case study of wolves in Scandinavia
Large carnivores are recolonizing areas of their historical range in Europe. This process has strong implications for conservation and management related to human-wildlife conflicts. Analyses and modelling of the observed mechanisms of spatial expansion can predict recolonization patterns under human influences. We demonstrate how spatially-explicit, agent-based models can assist to identify and predict how humans impact shape large carnivore recolonizations. Using detailed data obtained through long-term surveillance of wolf territories, we identified the mechanisms of recolonization and predicted the spatio-temporal patterns of expansion of the wolf in the Scandinavian Peninsula. We disentangled the observed mechanisms of expansion to develop WOLVES (Wolf Virtual Expansion Simulator), an agent-based model software. We applied the model to investigate in silico the observed lack of wolf recolonization into the suitable but densely human-populated area of southern Sweden and projected the expansion into the future. We tested the impact of traffic barriers and territory termination (wolf mortality most likely due to culling and poaching) on the observed recolonization in the south. Simulations identified that traffic infrastructures impacted only at configurations of insurmountable barriers unlikely to occur in Scandinavia, while low rates of territory termination had a major impact on the recolonization. Simulating until 2030 predicts that wolves will not colonize southern Sweden, which highlights the complexities of this process in areas of increased human-influence. The capability of simulators to test hypotheses and discriminate constraints of future population development makes them a valuable tool for ecologists, managers, and decision-makers involved in regional and transboundary conservation challenges of large carnivore recolonizations
Implementation of a Machine Tool Retrofit System
Small and medium-sized companies increasingly turning their attention towards the fourth industrial revolution. In order to increase their own long-term competitiveness, there is a growing desire to make production smarter, more efficient, safer and more sustainable through new technologies. Often, however, existing plants cannot be easily replaced by modern equipment. The reasons for this can be high investment costs, excessive downtimes or the unavailability of an equivalent machine. An alternative solution to the purchase of new equipment is the modernisation or expansion of existing systems, also called retrofitting. Thus, this paper deals with the retrofit process of a machine tool, whereby the software architecture of the control unit is the primary concern of this work
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