Typologie analytique et structurale des complexes du Moustérien de la Grotte Gatzarria (Ossas-Suhare, Pays Basque) et de leurs relations avec ceux de l'Abri Olha 2 (Cambo, Pays Basque)

La Grotte Gatzarria (Suhare, Pays Basque), fouillée par G. Laplace entre 1961 et 1976, présente une remarquable séquence archéologique concernant le Paléolithique moyen et les premiers complexes industriels du Paléolithique supérieur. Plusieurs travaux ayant été consacrés aux différentes questions relatives aux niveaux Castelperronien, Protoaurignaciens, Aurignaciens et Gravettien, cet article a pour but l' étude des couches a industries moustéro'ides. Dans ce sens, la composition industrielle de l' ensemble archéologique de base Cr (Würm 1) étant quantitativement tres insuffisante, l'analyse a été effectuée sur les ensembles bien représentés, le moyen de Cjr (Würm Ha) et le supérieur de Cj (Würm Hb). En conséquence, tandis que Cjr est defini comme complexe industriel a racloirs caréno'ides, Cj est distingué comme complexe a racloirs plats complémentairement enrichi de formes leptolithiques. Finalement, la comparaison analytique et structurale entre les séries de Gatzarria et celles de l' Abri Olha 2 (Cambo, Pays Basque), étudiées méthodologiquement selon les memes criteres, permet, d'une part, de rapprocher certaines industries des deux gisements, et, d'autre part, de classer provisoirement l' ensemble de ces industries moustéro'ides en quatre facies morphotechniques.Gatzarria Cave, excavated by G. Laplace between 1961-1976, displays a remarkable archeological sequence apropos of the Middle Paleolithic and the industrial complexes of the Upper Paleolithic periods. It being the case that various studies have been dedicated lO the different questions relating to the Castelperronian, Protoaurignacian, Aurignacian, and Gravettian levels, this article has taken as its objective the study of the levels with mousteroid industries. In this sense, since the quantity of industrial composition of the archeological set of Cr (Würm 1) was insufficient, the analysis has been conducted using well represented sets, such as the middle one of Cjr (Würm Ha) and the upper one of Cj (Würm Ilb). Accordingly, Cjr is defined as an industrial set of charenoid side scrapers, and Cjr is known as a flat side scraper, which in addition is enriched with leptolithic shapes. Finally, the analytic and structural comparison between the series of Gatzarria and the ones from Olha 2 (Cambo, Basque Country), if methodologically studied using the same criteria, allow us to on one hand, relate some of the industries found on the sites, and on the other temporarily classify this set of mousteroid industries into four morphotechnical facies

Secular evolution of a satellite by tidal effect. Application to Triton

Some of the satellites in the Solar System, including the Moon, appear to have been captured from heliocentric orbits at some point in their past, and then have evolved to the present configurations. The exact process of how this trapping occurred is unknown, but the dissociation of a planetesimal binary in the gravitational field of the planet, gas drag, or a massive collision seem to be the best candidates. However, all these mechanisms leave the satellites in elliptical orbits that need to be damped to the present almost circular ones. Here we give a complete description of the secular tidal evolution of a satellite just after entering a bounding state with the planet. In particular, we take into account the spin evolution of the satellite, which has often been assumed synchronous in previous studies. We apply our model to Triton and successfully explain some geophysical properties of this satellite, as well as the main dynamical features observed for the Neptunian system.Comment: 4 pages, 1 figur

Loop quantum cosmology and slow roll inflation

In loop quantum cosmology (LQC) the big bang is replaced by a quantum bounce which is followed by a robust phase of super-inflation. Rather than growing unboundedly in the past, the Hubble parameter \emph{vanishes} at the bounce and attains a \emph{finite universal maximum} at the end of super-inflation. These novel features lead to an unforeseen implication: in presence of suitable potentials all LQC dynamical trajectories are funneled to conditions which virtually guarantee slow roll inflation with more than 68 e-foldings, {without any input from the pre-big bang regime}. This is in striking contrast to certain results in general relativity, where it is argued that the a priori probability of obtaining a slow roll with 68 or more e-foldings is suppressed by a factor $e^{-204}$.Comment: 5 pages, 1 tabl

The Cosmic Carbon Footprint of Massive Stars Stripped in Binary Systems

The cosmic origin of carbon, a fundamental building block of life, is still uncertain. Yield predictions for massive stars are almost exclusively based on single-star models, even though a large fraction interact with a binary companion. Using the MESA stellar evolution code, we predict the amount of carbon ejected in the winds and supernovae of single and binary-stripped stars at solar metallicity. We find that binary-stripped stars are twice as efficient at producing carbon (1.5–2.6 times, depending on choices regarding the slope of the initial mass function and black hole formation). We confirm that this is because the convective helium core recedes in stars that have lost their hydrogen envelope, as noted previously. The shrinking of the core disconnects the outermost carbon-rich layers created during the early phase of helium burning from the more central burning regions. The same effect prevents carbon destruction, even when the supernova shock wave passes. The yields are sensitive to the treatment of mixing at convective boundaries, specifically during carbon-shell burning (variations up to 40%), and improving upon this should be a central priority for more reliable yield predictions. The yields are robust (variations less than 0.5%) across our range of explosion assumptions. Black hole formation assumptions are also important, implying that the stellar graveyard now explored by gravitational-wave detections may yield clues to better understand the cosmic carbon production. Our findings also highlight the importance of accounting for binary-stripped stars in chemical yield predictions and motivates further studies of other products of binary interactions

The expansion of stripped-envelope stars:Consequences for supernovae and gravitational-wave progenitors

Massive binaries that merge as compact objects are the progenitors of gravitational-wave sources. Most of these binaries experience one or more phases of mass transfer, during which one of the stars loses part or all of its outer envelope and becomes a stripped-envelope star. The evolution of the size of these stripped stars is crucial in determining whether they experience further interactions and their final fate. We present new calculations of stripped-envelope stars based on binary evolution models computed with MESA. We use these to investigate their radius evolution as a function of mass and metallicity. We further discuss their pre-supernova observable characteristics and potential consequences of their evolution on the properties of supernovae from stripped stars. At high metallicity we find that practically all of the hydrogen-rich envelope is removed, in agreement with earlier findings. Only progenitors with initial masses below 10\Msun expand to large radii (up to 100\Rsun), while more massive progenitors stay compact. At low metallicity, a substantial amount of hydrogen remains and the progenitors can, in principle, expand to giant sizes (> 400\Rsun), for all masses we consider. This implies that they can fill their Roche lobe anew. We show that the prescriptions commonly used in population synthesis models underestimate the stellar radii by up to two orders of magnitude. We expect that this has consequences for the predictions for gravitational-wave sources from double neutron star mergers, in particular for their metallicity dependence.Comment: Main text 17 pages, 7 figures, accepted for publication in Astronomy & Astrophysic

Convenient and versatile route to 2-alkyl-19-nor-analogues of calcitriol

Since decades, researchers have been intrigued by 1α,25-dihydroxy vitamin D3 (calcitriol) in various important cellular processes. Apart from its well-known role in calcium- and phosphate-regulation, this steroid metabolite presents also a remarkably broad spectrum of transitions. Most notably, the ability to inhibit cell growth and stimulate cell differentiation upon binding to the vitamin D receptor (VDR) turns calcitriol into a potential drug candidate. Moreover, the VDR- receptor’s found in over 30 different tissues in the human body, including various tumors, opening up new therapeutic areas. However, dosing test animals with the required supra-fysiological amounts of calcitriol causes acute hypercalcemia leading to bone deformation, hardening of soft organs and eventually mortality. Labour-intensive SAR studies on the complex vitamin D scaffold established that calcemic activities could be separated from the therapeutic activities by using analogues thereof. In fact, analogues are now in advanced stages of research, e.g. inecalcitol is in clinical phase II for the treatment of chronic lymphocytic leukemia and Daivonex (calcipotriol, Leo pharmaceuticals) is already available as a treatment for hyperproliferative disorder (psoriasis). We have shown that two calcitriol modifications, where a methyl or ethyl group is introduced at the 2α-position, had little calcemic effects in mice, while remaining potent in in vitro assays on inhibition of human cancer cell growth. However, the initially developed synthetic routes were highly inefficient and only gave sub-milligram amounts of these analogues. Here, we will present a practical route for novel A-ring building blocks, starting from D-(-)-quinic acid allowing larger scale synthesis of these sort of analogues, as required for studies in animal models of various diseases. Such extensive in vivo tests on these promising 2-alkyl-14,20-bisepi-19-nor-23-yne-analogues are now in progress at the KULeuven

WISER deliverable D3.1-4: guidance document on sampling, analysis and counting standards for phytoplankton in lakes

Sampling, analysis and counting of phytoplankton has been undertaken in European lakes for more than 100 years (Apstein 1892, Lauterborn 1896, Lemmermann 1903, Woloszynska 1912, Nygaard 1949). Since this early period of pioneers, there has been progress in the methods used to sample, fix, store and analyse phytoplankton. The aim of the deliverable D3.1-4 is to select, harmonize and recommend the most optimal method as a basis for lake assessment. We do not report and review the huge number of European national methods or other published manuals for phytoplankton sampling and analysis that are available. An agreement on a proper sampling procedure is not trivial for lake phytoplankton. In the early 20th century, sampling was carried out using plankton nets. An unconcentrated sample without any pre-screening is required for quantitative phytoplankton analysis, for which various water samplers were developed. Sampling of distinct water depths or an integral sample of the euphotic zone affects the choice of the sampler and sampling procedure. The widely accepted method to quantify algal numbers together with species determination was developed by Utermöhl (1958), who proposed the counting technique using sediment chambers and inverse microscopy. This is the basis for the recently agreed CEN standard “Water quality - Guidance standard on the enumeration of phytoplankton using inverted microscopy (Utermöhl technique)” (CEN 15204, 2006). This CEN standard does not cover the sampling procedure or the calculation of biovolumes for phytoplankton species, although Rott (1981), Hillebrand et al (1999) and Pohlmann & Friedrich (2001) have contributed advice on how to calculate taxa biovolumes effectively. Willén (1976) suggested a simplified counting method, when counting 60 individuals of each species. For the Scandinavian region an agreed phytoplankton sampling and counting manual was compiled, which has been in use for about 20 years (Olrik et al. 1998, Blomqvist & Herlitz 1998). It is very unfortunate that no European guidance on sampling of phytoplankton in lakes was agreed before the phytoplankton assessment methods for the EU-WFD were developed and intercalibrated by Member States. In 2008 an initiative by the European Commission (Mandate M424) for two draft CEN standards on sampling in freshwaters and on calculation of phytoplankton biovolume was unfortunately delayed by administrative difficulties. Recently a grant agreement was signed between the Commission and DIN (German Institute for Standardization) in January 2012 to develop these standards. We believe this WISER guidance document can usefully contribute to these up-coming standards

The Measure Problem in Cosmology

The Hamiltonian structure of general relativity provides a natural canonical measure on the space of all classical universes, i.e., the multiverse. We review this construction and show how one can visualize the measure in terms of a "magnetic flux" of solutions through phase space. Previous studies identified a divergence in the measure, which we observe to be due to the dilatation invariance of flat FRW universes. We show that the divergence is removed if we identify universes which are so flat they cannot be observationally distinguished. The resulting measure is independent of time and of the choice of coordinates on the space of fields. We further show that, for some quantities of interest, the measure is very insensitive to the details of how the identification is made. One such quantity is the probability of inflation in simple scalar field models. We find that, according to our implementation of the canonical measure, the probability for N e-folds of inflation in single-field, slow-roll models is suppressed by of order exp(-3N) and we discuss the implications of this result.Comment: 22 pages, 6 figures. Revised version with clarifying remarks on meaning of adopted measure, extra references and minor typographical correction