Modelling short-term ultraviolet exposure as an alternative to individual dosimetry

Background: Excessive exposure to solar Ultra-Violet (UV) light is the main cause of most skin cancers in humans. Factors such as the increase of solar irradiation at ground level (anthropic pollution), the rise in standard of living (vacation in sunny areas), and (mostly) the development of outdoor activities have contributed to increase exposure. Thus, unsurprisingly, incidence of skin cancers has increased over the last decades more than that of any other cancer. Melanoma is the most lethal cutaneous cancer, while cutaneous carcinomas are the most common cancer type worldwide. UV exposure depends on environmental as well as individual factors related to activity. The influence of individual factors on exposure among building workers was investigated in a previous study. Posture and orientation were found to account for at least 38% of the total variance of relative individual exposure. A high variance of short-term exposure was observed between different body locations, indicating the occurrence of intense, subacute exposures. It was also found that effective short-term exposure ranged between 0 and 200% of ambient irradiation, suggesting that ambient irradiation is a poor predictor of effective exposure. Various dosimetric techniques enable to assess individual effective exposure, but dosimetric measurements remain tedious and tend to be situation-specific. As a matter of facts, individual factors (exposure time, body posture and orientation in the sun) often limit the extrapolation of exposure results to similar activities conducted in other conditions. Objective: The research presented in this paper aims at developing and validating a predictive tool of effective individual exposure to solar UV. Methods: Existing computer graphic techniques (3D rendering) were adapted to reflect solar exposure conditions and calculate short-term anatomical doses. A numerical model, represented as a 3D triangular mesh, is used to represent the exposed body. The amount of solar energy received by each "triangle is calculated, taking into account irradiation intensity, incidence angle and possible shadowing from other body parts. The model take into account the three components of the solar irradiation (direct, diffuse and albedo) as well as the orientation and posture of the body. Field measurements were carried out using a forensic mannequin at the Payerne MeteoSwiss station. Short-term dosimetric measurements were performed in 7 anatomical locations for 5 body postures. Field results were compared to the model prediction obtained from the numerical model. Results: The best match between prediction and measurements was obtained for upper body parts such as shoulders (Ratio Modelled/Measured; Mean = 1.21, SD = 0.34) and neck (Mean = 0.81, SD = 0.32). Small curved body parts such as forehead (Mean = 6.48, SD = 9.61) exhibited a lower matching. The prediction is less accurate for complex postures such as kneeling (Mean = 4.13, SD = 8.38) compared to standing up (Mean = 0.85, SD = 0.48). The values obtained from the dosimeters and the ones computed from the model are globally consistent. Conclusion: Although further development and validation are required, these results suggest that effective exposure could be predicted for a given activity (work or leisure) in various ambient irradiation conditions. Using a generic modelling approach is of high interest in terms of implementation costs as well as predictive and retrospective capabilities.

Implications of the serpentine phase transition on the behaviour of beryllium and lithium-boron of subducted ultramafic rocks

The Totalp-Platta-Malenco ophiolites in the Eastern Central Alps offer a unique opportunity to study the behaviour of Li, Be and B in ultramafic rocks in response to serpentinization and to progressive Alpine metamorphism. These units represent the remnants of a former ocean-continent transition that was intensely serpentinized during exposure on the Jurassic seafloor of the Ligurian Tethys. From north to the south, three isograd reactions (lizardite double right arrow antigorite + brucite; lizardite + talc double right arrow antigorite; lizardite + tremolite double right arrow antigorite + diopside) have been used to quantify the evolution of the light element content of metamorphic minerals. We determined the Li, Be and B concentrations in major silicate minerals from the ultramafic bodies of Totalp, Platta and Malenco by secondary ion mass spectrometry. Mantle minerals have Be concentrations (e.g. <0.001-0.009 mu g/g in olivine) similar to the metamorphic minerals that replace them (e.g. <0.001-0.016 mu g/g in serpentine). The mantle signature of Be is thus neither erased during seafloor alteration nor by progressive metamorphism from prehnite-pumpellyite to epidote-amphibolite facies. In contrast, the Li and B inventories of metamorphic minerals are related to the lizardite-to-antigorite transition. Both elements display higher concentrations in the low-temperature serpentine polymorph lizardite (max. 156 mu/g Li, max. 318 mu g/g B) than in antigorite (max. 0.11 mu g/g Li, max. 12 mu g/g B). Calculated average B/Li ratios for lizardite (similar to 1395) and antigorite (similar to 115) indicate that Li fractionates from B during the lizardite-to-antigorite transition during prograde metamorphism in ultramafic rocks. In subduction zones, this signature is likely to be recorded in the B-rich nature of forearc fluids. Relative to oceanic mantle the Be content of mantle clinopyroxene is much higher, but similar to Be values from mantle xenoliths and subduction-related peridotite massifs. These data support previous hypothesis that the mantle rocks from the Eastern Central Alps have a subcontinental origin. We conclude that Be behaves conservatively during subduction metamorphism of ultramafic rocks, at least at low-temperature, and thus retains the fingerprint of ancient subduction-related igneous events in mantle peridotites. (C) 2010 Elsevier Ltd. All rights reserved.

Genome organization and gene expression shape the transposable element distribution in the Drosophila melanogaster euchromatin.

The distribution of transposable elements (TEs) in a genome reflects a balance between insertion rate and selection against new insertions. Understanding the distribution of TEs therefore provides insights into the forces shaping the organization of genomes. Past research has shown that TEs tend to accumulate in genomic regions with low gene density and low recombination rate. However, little is known about the factors modulating insertion rates across the genome and their evolutionary significance. One candidate factor is gene expression, which has been suggested to increase local insertion rate by rendering DNA more accessible. We test this hypothesis by comparing the TE density around germline- and soma-expressed genes in the euchromatin of Drosophila melanogaster. Because only insertions that occur in the germline are transmitted to the next generation, we predicted a higher density of TEs around germline-expressed genes than soma-expressed genes. We show that the rate of TE insertions is greater near germline- than soma-expressed genes. However, this effect is partly offset by stronger selection for genome compactness (against excess noncoding DNA) on germline-expressed genes. We also demonstrate that the local genome organization in clusters of coexpressed genes plays a fundamental role in the genomic distribution of TEs. Our analysis shows that-in addition to recombination rate-the distribution of TEs is shaped by the interaction of gene expression and genome organization. The important role of selection for compactness sheds a new light on the role of TEs in genome evolution. Instead of making genomes grow passively, TEs are controlled by the forces shaping genome compactness, most likely linked to the efficiency of gene expression or its complexity and possibly their interaction with mechanisms of TE silencing.

On the binary nature of the γ-ray sources AGL J2241+4454 (= MWC 656) and HESS J0632+057 (= MWC 148)

We present optical spectroscopy of MWC 656 and MWC 148, the proposed optical counterparts of the gamma-ray sources AGL J2241+4454 and HESS J0632+0 57, respectively. The main parameters of the Halpha emission line (EW, FWHM and centroid velocity) in these stars are modulated on the proposed orbital periods of 60.37 and 321 days, respectively. These modulations are likely produced by the resonant interaction of the Be discs with compact stars in eccentric orbits. We also present radial velocity curves of the optical stars folded on the above periods and obtain the first orbital elements of the two gamma-ray sources thus confirming their binary nature. Our orbital solution support eccentricities e~0.4 and 0.83+-0.08 for MWC 656 and MWC 148, respectively. Further, our orbital elements imply that the X-ray outbursts in HESS J0632+057/MWC 148 are delayed ~0.3 orbital phases after periastron passage, similarly to the case of LS I +61 303. In addition, the optical photometric light curve maxima in AGL J2241+4454/MWC 656 occur ~0.25 phases passed periastron, similar to what is seen in LS I +61 303. We also find that the orbital eccentricity is correlated with orbital period for the known gamma-ray binaries. This is explained by the fact that small stellar separations are required for the efficient triggering of VHE radiation. Another correlation between the EW of Halpha and orbital period is also observed, similarly to the case of Be/X-ray binaries. These correlations are useful to provide estimates of the key orbital parameters Porb and e from the Halpha line in future Be gamma-ray binary candidates.

Evidence for oxygen-island formation on Al(111): Cluster-model theory and x-ray photoelectron spectroscopy

The O 1s x-ray photoelectron spectroscopy spectrum for Al(111)/O at 300 K shows two components whose behavior as a function of time and variation of detection angle are consistent with either (a) a surface species represented by the higher binding-energy (BE) component and a subsurface species represented by the lower BE component, or (b) small close-packed oxygen islands with the interior atoms represented by the lower BE component and the perimeter atoms by the higher BE component. We have modeled both situations using ab initio Hartree-Fock wave functions for clusters of Al and O atoms. For an O atom in a threefold site, it was found that a below-surface position gave a higher O 1s BE than an above-surface position, incompatible with interpretation (a). This change in the O 1s BE could arise because the bond for O to Al may have a more covalent character when the O is below the surface than when it is above the surface. We present evidence consistent with this view. An O adatom island with all the O atoms in threefold sites gives calculated O 1s BE's which are significantly higher for the perimeter O atoms. Further, the results for an isolated O island without the Al substrate present also give higher BE¿s for the perimeter atoms. Both these results are consistent with interpretation (b). Published scanning-tunneling-microscopy data supports the suggestion that the chemisorbed state consists of small, close-packed islands, whereas the presence of two vibrational modes in high-resolution electron-energy-loss spectroscopy data has been interpreted as representing surface and subsurface oxygen atoms. In light of the present results, we suggest that a vibrational interpretation in terms of interior and perimeter adatoms should be considered.

Diverging Cave- and River-Dwelling Newts Exert the Same Mate Preference in their Native Light Conditions

When colonizing a new habitat, populations must adapt their sexual behaviour to new ecological constraints. Because caves display drastically different conditions from surface habitats and cave animals are deprived from visual information, hypogean populations are expected to have modified their mate preference and signalling behaviour after cave colonization. Here, we experimentally examined the female preference and the sexual behaviour of brook newts Calotriton asper from different cave and river populations, either in light or in darkness. Our results suggest that females prefer large individuals in both hypogean and epigean populations, but that this preference is only expressed in the light conditions of their native habitat. Hence, some mate choice criteria would be maintained across genetically divergent populations and throughout dissimilar habitats. However, this sexual behaviour is likely to be expressed via a different sensory pathway in the different habitats, suggesting that a sensory shift has occurred in cave populations, enabling animals to communicate through a non-visual channel.

Moottoripolttoaineiden ominaisuuksien mallintaminen

Työn tavoitteena on selvittää voidaanko neuroverkkoa käyttää mallintamaan ja ennustamaan polttoaineen vaikutusta nykyaikaisen auton päästöihin. Näin pystyttäisiin vähentämään aikaa vievien ja kalliiden koeajojen tarvetta. Työ tehtiin Lappeenrannan teknillisen yliopiston ja Fortum Oy:n yhteistyöprojektissa. Työssä tehtiin kolme erilaista mallia. Ensimmäisenä tehtiin autokohtainen malli, jolla pyrittiin ennustamaan autokohtaista käyttäytymistä. Toiseksi kokeiltiin mallia, jossa automalli oli yhtenä syötteenä. Kolmantena yritettiin kiertää eräitä aineiston ongelmia käyttämällä "sumeutettuja" polttoaineiden koostumuksia. Työssä käytettiin MLP-neuroverkkoa, joka opetettiin backpropagation algoritmilla. Työssä havaittiin ettei käytettävissä olleella aineistolla ja käytetyillä malleilla pystytä riittävällä tarkkuudella mallintamaan polttoaineen vaikutusta päästöihin. Aineiston ongelmia olivat mm. suuret mittausvarianssit, aineiston pieni määrä sekä aineiston soveltumattomuus neuroverkolla mallintamiseen.

Long-term X-ray variability of the microquasar system LS5039/RX J1826.2-1450

We report on the results of the spectral and timing analysis of a BeppoSAX observation of the microquasar system LS 5039/RX J1826.2-1450. The source was found in a low-flux state with Fx(1-10 keV)= 4.7 x 10^{-12} erg cm^{-2} s^{-1}, which represents almost one order of magnitude lower than a previous RXTE observation 2.5 years before. The 0.1--10 keV spectrum is described by an absorbed power-law continuum with photon-number spectral index Gamma=1.8+-0.2 and hydrogen column density of NH=1.0^{+0.4}_{-0.3} x 10^{22} cm^{-2}. According to the orbital parameters of the system the BeppoSAX observation covers the time of an X-ray eclipse should one occur. However, the 1.6-10 keV light curve does not show evidence for such an event, which allows us to give an upper limit to the inclination of the system. The low X-ray flux detected during this observation is interpreted as a decrease in the mass accretion rate onto the compact object due to a decrease in the mass-loss rate from the primary.

MAGIC TeV Gamma-Ray Observations of Markarian 421 during Multiwavelength Campaigns in 2006

Wide-range spectral coverage of blazar-type active galactic nuclei is of paramount importance for understanding the particle acceleration mechanisms assumed to take place in their jets. The Major Atmospheric Gamma Imaging Cerenkov (MAGIC) telescope participated in three multiwavelength (MWL) campaigns, observing the blazar Markarian (Mkn) 421 during the nights of April 28 and 29, 2006, and June 14, 2006. Aims. We analyzed the corresponding MAGIC very-high energy observations during 9 nights from April 22 to 30, 2006 and on June 14, 2006. We inferred light curves with sub-day resolution and night-by-night energy spectra. Methods. MAGIC detects γ-rays by observing extended air showers in the atmosphere. The obtained air-shower images were analyzed using the standard MAGIC analysis chain. Results. A strong γ-ray signal was detected from Mkn 421 on all observation nights. The flux (E > 250 GeV) varied on night-by-night basis between (0.92±0.11) × 10-10 cm-2 s-1 (0.57 Crab units) and (3.21±0.15) × 10-10 cm-2 s-1 (2.0 Crab units) in April 2006. There is a clear indication for intra-night variability with a doubling time of 36± min on the night of April 29, 2006, establishing once more rapid flux variability for this object. For all individual nights γ-ray spectra could be inferred, with power-law indices ranging from 1.66 to 2.47. We did not find statistically significant correlations between the spectral index and the flux state for individual nights. During the June 2006 campaign, a flux substantially lower than the one measured by the Whipple 10-m telescope four days later was found. Using a log-parabolic power law fit we deduced for some data sets the location of the spectral peak in the very-high energy regime. Our results confirm the indications of rising peak energy with increasing flux, as expected in leptonic acceleration models.

Interventions présumées des scribes concernant le motif de l'arbre sacré dans le Pentateuque

Abstract: This article deals with several presumed scribal interventions which all concern the sacred tree motif. One finds deliberate changes in the MT, in the Septuagint, in Targum Onkelos and in the Vulgate. The Greek translators of Genesis and Samuel (1-2 Kingdoms) avoided rendering the word אשׁל "tamarisk" by its equivalent μυρίκη, chosing instead the word ἄρουρα "field". Similarly, the Greek translator of Genesis, in the passage of the death of Rebecca's nurse Deborah, passed over the motif of her burial under a grand tree. According to the hypothesis of the present article, all four changes are related to one other; they might be due to the translator's fear to connect the respective texts with traditions and customs concerning the Egyptian god Osiris. On the other side, a scribe of the proto-Massoretic tradition modified the readings mentioning the large tree of Mamre close to Hebron. By changing the noun's number from singular to plural the corrector tried to conceal the existence and importance of the sacred tree in the tradition of Abraham. By contrast, the scribe did not modify texts related to the sacred tree of Shechem. This disparity of treatment may be explained by the fact that, in the view of the Judean scribe, the tree of Shechem would put the Samaritans in a bad light. Finally, the authors of Targum Onkelos and of the Vulgate intervened almost systematically in Pentateuchal texts having the terms אֵלוֹן) אלון or אַלּוֹן ), which always designate a holy tree. The two expressions are rendered by terms referring to plains (Targum Onkelos) or a valley (Vulgate).

Colony-colony interactions between highly invasive ants

Among invasive species, ants are a particularly prominent group with enormous impacts on native biodiversity and ecosystem functioning. Globalization and on-going climate change are likely to increase the rate of ant invasions in the future, leading to simultaneous introductions of several highly invasive species within the same area, Here, we investigate pairwise interactions among four highly invasive species, Linepithema humile,Lashis neglectus, Pheidole megacephala and Wasmannia auropunctata, at the whole colony level, using a laboratory set-up. :Each colony consisted of 300 workers and one queen. The number of surviving workers in the competing colonies was recorded daily over 7 weeks. We modelled the survival of each colony during pairwise colony interactions, using a nonlinear model characterizing the survival dynamics of each colony individually. The least dominant species was P. megacephala, which always went extinct. Interactions among the three other species showed more complex dynamics, rendering the outcome of the interactions less predictable. Overall, W auropunctata and L neglectus were the most dominant species. This study shows the importance of scaling up to the colony level in order to gain realism in predicting the outcome of multiple invasions.

Gamma spectrometry and gamma and X-ray tomography of nuclear fuel

The purpose of gamma spectrometry and gamma and X-ray tomography of nuclear fuel is to determine both radionuclide concentration and integrity and deformation of nuclear fuel. The aims of this thesis have been to find out the basics of gamma spectrometry and tomography of nuclear fuel, to find out the operational mechanisms of gamma spectrometry and tomography equipment of nuclear fuel, and to identify problems that relate to these measurement techniques. In gamma spectrometry of nuclear fuel the gamma-ray flux emitted from unstable isotopes is measured using high-resolution gamma-ray spectroscopy. The production of unstable isotopes correlates with various physical fuel parameters. In gamma emission tomography the gamma-ray spectrum of irradiated nuclear fuel is recorded for several projections. In X-ray transmission tomography of nuclear fuel a radiation source emits a beam and the intensity, attenuated by the nuclear fuel, is registered by the detectors placed opposite. When gamma emission or X-ray transmission measurements are combined with tomographic image reconstruction methods, it is possible to create sectional images of the interior of nuclear fuel. MODHERATO is a computer code that simulates the operation of radioscopic or tomographic devices and it is used to predict and optimise the performance of imaging systems. Related to the X-ray tomography, MODHERATO simulations have been performed by the author. Gamma spectrometry and gamma and X-ray tomography are promising non-destructive examination methods for understanding fuel behaviour under normal, transient and accident conditions.

Candidate counterparts to the soft gamma-ray flare in the direction od LSI+61303

A short duration burst reminiscent of a soft gamma-ray repeater/anomalous X-ray pulsar behaviour was detected in the direction of LS I +61 303 by the Swift satellite. While the association with this well known gamma-ray binary is likely, a different origin cannot be excluded. Aims. We explore the error box of this unexpected flaring event and establish the radio, near-infrared and X-ray sources in our search for any peculiar alternative counterpart. Methods. We carried out a combined analysis of archive Very Large Array radio data of LS I +61 303 sensitive to both compact and extended emission. We also reanalysed previous near infrared observations with the 3.5 m telescope of the Centro Astronómico Hispano Alemán and X-ray observations with the Chandra satellite. Results. Our deep radio maps of the LS I +61 303 environment represent a significant advancement on previous work and 16 compact radio sources in the LS I +61 303 vicinity are detected. For some detections, we also identify near infrared and X-ray counterparts. Extended emission features in the field are also detected and confirmed. The possible connection of some of these sources with the observed flaring event is considered. Based on these data, we are unable to claim a clear association between the Swift-BAT flare and any of the sources reported here. However, this study represents the most sophisticated attempt to determine possible alternative counterparts other than LS I +61 303.

Thermal behaviour study of solid state compounds of manganese (II), zinc (II) and lead (II) with cinnamic acid

Compounds of cinnamic acid with manganese, zinc and lead have been prepared in aqueous solution. Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC), X-ray diffraction and complexometry have been used in the characterization as well as in the study of the thermal stability and interpretation concerning the thermal decomposition.

Thermal behaviour studies of solid state compounds of cinnamylidenepyruvate with trivalent lanthanides and yttrium (III) in an atmosphere of CO2

Solid state cinnamylidenepyruvate of trivalent lanthanides (except for promethium) and yttrium, were prepared. Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC), X-ray diffraction powder patterns and complexometry were used to characterize and to study the thermal behavior of these compounds in a dynamic CO2 atmosphere. The results obtained showed significative differences on the thermal stability and thermal decomposition of these compounds, with regard to the thermal behavior study in a dynamic air atmosphere.