63 research outputs found
Quasi Free 238U (e,e'f)-Cross Section in Macroscopic-Microscopic Approach
We present the result of a theoretical study of inclusive quasi free
electrofission of U. The off-shell cross sections for the quasi free
reaction stage have been calculated within the Plane Wave Impulse Approximation
(PWIA), using a Macroscopic -Microscopic description of the proton and neutron
single particle momentum distributions. Electron wave function distortion
corrections were included using the effective momentum approximation, and the
Final State Interaction (FSI) effects were calculated using an optical
potential. The fissility for the proton single hole excited states of the
residual nucleus Pa was calculated both without and with contributions
of the pre-equilibrium emission of the particles. The fissility for
residual nuclei was calculated within the compound nucleus model.
The cross sections thus obtained were compared with available
experimental data.Comment: 26 pages, 7 figure
Testing the Effect of Relative Pollen Productivity on the REVEALS Model : A Validated Reconstruction of Europe-Wide Holocene Vegetation
Reliable quantitative vegetation reconstructions for Europe during the Holocene are crucial to improving our understanding of landscape dynamics, making it possible to assess the past effects of environmental variables and land-use change on ecosystems and biodiversity, and mitigating their effects in the future. We present here the most spatially extensive and temporally continuous pollen-based reconstructions of plant cover in Europe (at a spatial resolution of 1° × 1°) over the Holocene (last 11.7 ka BP) using the 'Regional Estimates of VEgetation Abundance from Large Sites' (REVEALS) model. This study has three main aims. First, to present the most accurate and reliable generation of REVEALS reconstructions across Europe so far. This has been achieved by including a larger number of pollen records compared to former analyses, in particular from the Mediterranean area. Second, to discuss methodological issues in the quantification of past land cover by using alternative datasets of relative pollen productivities (RPPs), one of the key input parameters of REVEALS, to test model sensitivity. Finally, to validate our reconstructions with the global forest change dataset. The results suggest that the RPPs.st1 (31 taxa) dataset is best suited to producing regional vegetation cover estimates for Europe. These reconstructions offer a long-term perspective providing unique possibilities to explore spatial-temporal changes in past land cover and biodiversity
Search for a W ' boson decaying to a muon and a neutrino in pp collisions at √s =7 TeV
This is the Pre-Print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 ElsevierA new heavy gauge boson, W', decaying to a muon and a neutrino, is searched for in pp collisions at a centre-of-mass of 7 TeV. The data, collected with the CMS detector at the LHC, correspond to an integrated luminosity of 36 inverse picobarns. No significant excess of events above the standard model expectation is found in the transverse mass distribution of the muon-neutrino system. Masses below 1.40 TeV are excluded at the 95% confidence level for a sequential standard-model-like W'. The W' mass lower limit increases to 1.58 TeV when the present analysis is combined with the CMS result for the electron channel.This work is supported by the FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences
and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3
(France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR
(Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)
Search for a heavy bottom-like quark in pp collisions at √s =7 TeV
This is the Pre-Print version of the Article. The official published version of the paper can be accessed from the link below - Copyright @ 2011 Elsevier.A search for pair-produced bottom-like quarks in pp collisions at sqrt(s) = 7 TeV is conducted with the CMS experiment at the LHC. The decay b' to tW is considered in this search. The b' b'-bar to tW^- t-bar W^+ process can be identified by the distinctive signature of trileptons and same-sign dileptons. With a data sample corresponding to an integrated luminosity of 34 inverse picobarns, no excess above the standard model background predictions is observed and a b' quark with a mass between 255 and 361 GeV/c^2 is excluded at the 95% confidence level.This work is supported by the FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences
and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3
(France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR
(Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)
An annotated list of ornamentals naturally found infected by Brevipalpus mite-transmitted viruses
The first cases of ornamental plants found infected by Brevipalpus transmitted viruses (BTV) were described in the 1990's from the region of Piracicaba, State of São Paulo, Brazil; subsequent cases were from other regions in the country and other American countries. Currently, 37 ornamental plant species (for the sake of simplicity, orchids being considered as a single species), belonging to 18 families of dicotyledons, have been reported hosting BTV. Because of the non systemic type of infection of these viruses, the localized diseases they cause are unimportant usually, but they have the potential to cause economic losses if severe outbreaks of Brevipalpus mite populations occur. Some ornamentals may serve as reservoirs to BTV known to cause serious damage to food crops as Citrus leprosis virus- cytoplasmic type (CiLV-C), passion fruit green spot virus (PFGSV) and Coffee ringspot virus (CoRSV).Os primeiros casos de plantas ornamentais encontradas naturalmente infetadas por vírus transmitidos por Brevipalpus (Acari: Tenuipalpidae) (VTB) foram registrados nos anos 1990 na região de Piracicaba, Estado de São Paulo, e ocorrências subseqüentes foram observadas em várias outras regiões do país e de outros países das Américas. Atualmente acham-se relatadas 37 espécies de ornamentais (para efeito de simplificação, orquídeas foram consideradas como única espécie) pertencentes a 18 famílias botânicas. Pelo fato de causarem apenas infecções localizadas, geralmente nas folhas, VTB em ornamentais não causam preocupações aos produtores, mas potencialmente podem causar perdas econômicas se ocorrerem explosões populacionais do ácaro vetor. Plantas ornamentais podem servir de reservatório de VTB de importância econômica como os vírus da leprose dos citros-tipo citoplasmático (CiLV-C), da mancha verde do maracujá (PFGSV) e da mancha anular do cafeeiro (CoRSV)
Analyse de la variabilité de la pigmentation de la peau durant la croissance
A sample of 916 young Spanish people (15 to 18 years old) of both sexes have been analyzed. The results show an skin pigmentation variation with the age, mainly in the arm, which show a progressive lightness of the skin. The reflectances for the forehead are more stable ; in the boys decreasing forehead values with the age were found. Statistically significant differences has been obtained from the comparison of both sexes and arm versus forehead. Girls have more clear skin than boys and the arm pigmentation is more clear than the forehead. Finally, the skin pigmentation variation of a sample from 6 to 18 years old people has been studied adding to the former sample another of the 6 to 14 years old children from the same population.L'échantillon, objet de cette étude, est composé de 916 jeunes espagnols des deux sexes, entre 15 et 18 ans. Les résultats indiquent l'existence de variations avec l'âge, surtout par rapport au bras, où la peau s'éclaircit de plus en plus. Le front présente une tendance plus stable et, dans le sexe masculin, les valeurs de réflectance diminuent avec l'âge. Des différences statistiques significatives ont été constatées en comparant les deux sexes et le bras au front. Les filles ont une peau plus claire que les garçons ; il en est de même du bras vis-à-vis du front. Cet échantillon a été réuni à un autre de la même population (enfants 6-14 ans) pour faire une revue globale des variations de la pigmentation cutanée pendant la période de 6 à 18 ans.Mesa M.S. Analyse de la variabilité de la pigmentation de la peau durant la croissance. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, XIII° Série. Tome 10 fascicule 1, 1983. pp. 49-60
Variabilité morphologique dans la péninsule ibérique : Epipaléolithique - Age ancien
The authors have studied in this paper the evolution throughout this period of the most important metrical characters of the neuro and splanchnocranium. Eleven series of populations from the Epipaleolithic to the end of the Ancient Age were analysed with the help of the deviation diagram, and the Bartlett, Fisher (F) and Student- Newman-Keuls tests. All the statistical procedures have allowed us to demonstrate a weak variability throughout this period and an anthropological structure fairly homogeneous between these populations. Only some of them were separated by their special morphological, chronological and cultural conditions.Nous avons analysé ici l'évolution à travers le temps des treize caractères métriques les plus importants du neuro et du splanchnocrâne, sur onze séries datées de l'Epipaléolithique au Moyen Age. L'étude a été réalisée à l'aide du diagramme de déviation, des tests de Bartlett, F. de Fisher et de celui de Student-Newman-Keuls. Tout cela nous a permis de constater une faible variabilité à travers le temps et une structure anthropologique assez homogène parmi les séries analysées, exception faite de quelques-unes qui se remarquent par leurs conditions spéciales morphologiques, chronologiques et culturelles.Garralda M. D., Mesa M.S. Variabilité morphologique dans la péninsule ibérique : Epipaléolithique - Age ancien. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, XIV° Série. Tome 1 fascicule 3, 1984. pp. 207-219
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