A new representative of the lichid genus Ohleum (Trilobita) from the Eifelian (Middle Devonian) of southern Belgium

Trilobites of the family Lichidae are relatively poorly diversified within the Eifelian mixed siliciclastic-carbonate succession of the southern margin of the Dinant Synclinorium (Belgium). Until now, they were only represented by species belonging to the genera Ceratarges and Eifliarges. The recent discovery of a well-preserved specimen within the Eifelian-aged Jemelle Formation in the Couvin area led us to propose the first detailed description of a representative of the genus Ohleum (O. magreani sp. nov.) in the Ardenne

Cosmogenic isotopes and geomagnetic signals in a Mediterranean sea sediment at 35000 y BP

In this paper we present the results on the relative changes of the geomagnetic field intensity measured in the Tyrrhenian sea core CT85-5 between 23 and 51 ky BP in order to investigate the origin of the enhancement of the cosmogenic isotope 10Be concentration, recently reported in the same core at 35 ky BP

Review on the leveraging of design information in 3D CAD models for subassemblies identification

In industrial manufacturing, both in the design and the production phase, the management of modern mechanical assemblies is becoming demanding due to their increasing complexity. The use of stable subassemblies concept constitutes a better alternative, which allows to independently treat smaller groups of the assembly's parts, also to achieve a parallel production. At this regard, several methods for automatic subassemblies identifi-cation, starting from the assembly CAD model, have been provided. However, most of the methodologies proposed rely on human intervention, especially in the model processing to make available essential data, while other details are ignored. After giving the definition of stable subassembly, this paper focuses on the application of stable subassemblies identification to industrial CAD models and highlights the issues arising. With the aim of ensuring a reliable CAD model analysis, starting point of the identification, the possible real engineering situations, both related to assembling methods and modelling techniques, are presented. Ap-proaches to algorithmically address them are then described, with the help of two examples of mechanical assemblies

Heat Treated NiP–SiC Composite Coatings: Elaboration and Tribocorrosion Behaviour in NaCl Solution

Tribocorrosion behaviour of heat-treated NiP and NiP–SiC composite coatings was investigated in a 0.6 M NaCl solution. The tribocorrosion tests were performed in a linear sliding tribometer with an electrochemical cell interface. It was analyzed the influence of SiC particles dispersion in the NiP matrix on current density developed, on coefficient of friction and on wear volume loss. The results showed that NiP–SiC composite coatings had a lower wear volume loss compared to NiP coatings. However, the incorporation of SiC particles into the metallic matrix affects the current density developed by the system during the tribocorrosion test. It was verified that not only the volume of co-deposited particles (SiC vol.%) but also the number of SiC particles per coating area unit (and consequently the SiC particles size) have made influence on the tribocorrosion behaviour of NiP–SiC composite coatings

Climate, geographic distribution and viviparity in Liolaemus (Reptilia; Squamata) species: when hypotheses need to be tested

La distribución de los reptiles, dada su dependencia de la temperatura, puede verse restringida en función del clima. En particular, se han planteado tres hipótesis que vinculan el clima con la distribución y el viviparismo en las especies de reptiles: i) hipótesis de clima variable, ii) hipótesis del clima frío e iii) hipótesis de manipulación materna. Entre las lagartijas de Sudamérica las especies del género Liolaemus se distribuyen tanto en ambientes cálidos como fríos y más del 50 % de ellas son vivíparas. En este trabajo estudiamos 47 especies de Liolaemus, tomando datos climáticos de sus sitios de colecta, su temperatura de preferencia (Tpref), el coeficiente de variación de la misma (CV) y los límites de tolerancia térmica (TT). Nuestros resultados no apoyan la hipótesis de clima variable, aunque ésta ha sido sustentada en estudios anteriores. Se encontró relación entre viviparismo y altitud, pero no entre viviparismo y las variables térmicas ambientales. Finalmente, las especies vivíparas de Liolaemus mostraron un comportamiento termorregulador más preciso que las especies ovíparas, reforzando la hipótesis de manipulación materna.Reptile’ distributions, under the light of their strong dependence on particular temperature requirements, may be constrained as a consequence of climate. The relationship between reptile viviparity and climate yielded two previously proposed hypotheses (the cold climate and the maternal manipulation hypotheses) that together with the climatic variability hypothesis; theoretically link climate, distribution and reproductive mode. The extensive variation in mean environmental temperature associated with changes in parity strategies has received much attention in this ectothermic group. Among Southamerican lizards, Liolaemus are distributed in cold and warm regions and more than 50 % of described species are viviparous. We studied 47 Liolaemus species considering climatic data where collected, preferred body temperature, its coefficient of variation and their thermal tolerance. Our results do not support the climate variability hypothesis, previously supported in other studies. We found a relationship between viviparity and elevation, but not between viviparity and thermal climatic variables. Finally, viviparous Liolaemus species showed more precise thermoregulatory behavior than oviparous ones, supporting the maternal manipulation hypothesis.Agencia Nacional de Promoción Científica y Tecnológica de Argentina (PICT 06-01205) y Consejo Nacional de Investigaciones científicas y Tecnológicas (PIP 2846 y PIP 6287)

Diffractive Higgs boson production at the Tevatron and LHC

Improved possibilities to find the Higgs boson in diffractive events, having less hadronic activity, depend on whether the cross section is large enough. Based on the soft color interaction models that successfully describe diffractive hard scattering at HERA and the Tevatron, we find that only a few diffractive Higgs events may be produced at the Tevatron, but we predict a substantial rate at the LHC.Comment: 4 pages, 4 figures, uses Revtex

First national intercomparison of solar ultraviolet radiometers in Italy

A blind intercomparison of ground-based ultraviolet (UV) instruments has been organized for the first time in Italy. The campaign was coordinated by the Environmental Protection Agency of Aosta Valley (ARPA Valle d'Aosta) and took place in Saint-Christophe (45.8 degrees N, 7.4 degrees E, 570 m a.s.l.), in the Alpine region, from 8 to 23 June 2010. It involved 8 institutions, 10 broadband radiometers, 2 filter radiometers and 2 spectroradiometers. Synchronized measurements of downward global solar UV irradiance at the ground were collected and the raw series were then individually processed by the respective operators on the base of their own procedures and calibration data. A radiative transfer model was successfully applied as an interpretative tool. The input parameters and output results are described in detail. The comparison was performed in terms of global solar UV Index and integrated UV-A irradiance against a well-calibrated double monochromator spectroradiometer as reference. An improved algorithm for comparing broadband data and spectra has been developed and is discussed in detail. For some instruments, we found average deviations ranging from -16% up to 20% relative to the reference and diurnal variations as large as 15% even in clear days. Remarkable deviations were found for the instruments calibrated in the manufacturers' facilities and never involved in field intercomparison. Finally, some recommendations to the UV operators based on the campaign results are proposed

Reggeon and pion contributions in semi-exclusive diffractive processes at HERA

A detailed analysis of semi-exclusive diffractive processes in e-p DIS at HERA, with the diffractive final states in the forward direction is presented. The contributions of the subleading f_2, \omega, a_2, \rho reggeons and the pion exchanges to the diffractive structure function with the forward proton or neutron are estimated. It is found that the (a_2,\rho) reggeons are entirely responsible for the forward neutron production at x_P < 10^{-3}. The \pi N production in the forward region is estimated using the Deck mechanism. The significance of this reaction for the processes measured at HERA, especially with the leading neutron, is discussed.Comment: Strongly revised version accepted for publication in Phys.Rev.D. Latex, 14 pages with 5 eps figures include

Evolution of the cosmic ray anisotropy above 10^{14} eV

The amplitude and phase of the cosmic ray anisotropy are well established experimentally between 10^{11} eV and 10^{14} eV. The study of their evolution into the energy region 10^{14}-10^{16} eV can provide a significant tool for the understanding of the steepening ("knee") of the primary spectrum. In this letter we extend the EAS-TOP measurement performed at E_0 around 10^{14} eV, to higher energies by using the full data set (8 years of data taking). Results derived at about 10^{14} and 4x10^{14} eV are compared and discussed. Hints of increasing amplitude and change of phase above 10^{14} eV are reported. The significance of the observation for the understanding of cosmic ray propagation is discussed.Comment: 4 pages, 3 figures, accepted for publication on ApJ Letter