7,793 research outputs found
Genetic variation between progenies of Pinus caribaea Morelet var. caribaea based on microsatellite markers.
Variação genética e ganho esperado na seleção de progênies de Pinus caribaea var. caribaea em Selvíria, MS.
No presente trabalho propôs-se quantificar a variação genética para caracteres de crescimento e estimar possíveis ganhos na seleção, a partir da utilização do índice multi-efeitos (IME), visando a transformação do teste de progênies P. caribaea var. caribaea em um pomar de sementes. O teste de progênies de Pinus caribaea var. caribaea foi implantado no município de Selvíria-MS. O delineamento experimental utilizado foi látice 10x10 triplo, com 99 progênies e uma testemunha comercial, em parcelas lineares com dez plantas, no espaçamento 3 m x 3 m. Os caracteres quantitativos altura total de plantas, diâmetro à altura do peito (DAP), volume, forma do fuste das árvores e sobrevivência das progênies foram avaliados aos 14, 15 e 16 anos de idade, sendo que aos 14 anos foi realizado um desbaste de 50% de intensidade. As variáveis foram analisadas pela metodologia do modelo linear misto. A variação genética encontrada para os caracteres analisados não foi significativa. As estimativas de herdabilidade apresentaram baixa magnitude e pouca variação para as diferentes idades. Aplicação do IME ao caráter DAP, dois anos após desbaste, proporcionou maiores ganhos do que a seleção entre e dentro de progênies. A melhor estratégia de seleção visando maiores ganhos e manter a diversidade genética é selecionar no máximo cinco indivíduos por progênies
NuSTAR + XMM-Newton monitoring of the neutron star transient AX J1745.6-2901
AX J1745.6-2901 is a high-inclination (eclipsing) transient neutron star (NS)
Low Mass X-ray Binary (LMXB) showcasing intense ionised Fe K absorption. We
present here the analysis of 11 XMM-Newton and 15 NuSTAR new data-sets
(obtained between 2013-2016), therefore tripling the number of observations of
AX J1745.6-2901 in outburst. Thanks to simultaneous XMM-Newton and NuSTAR
spectra, we greatly improve on the fitting of the X-ray continuum. During the
soft state the emission can be described by a disk black body (
keV and inner disc radius km), plus hot ( keV)
black body radiation with a small emitting radius ( km)
likely associated with the boundary layer or NS surface, plus a faint
Comptonisation component. Imprinted on the spectra are clear absorption
features created by both neutral and ionised matter. Additionally, positive
residuals suggestive of an emission Fe K disc line and consistent with
relativistic ionised reflection are present during the soft state, while such
residuals are not significant during the hard state. The hard state spectra are
characterised by a hard () power law, showing no evidence
for a high energy cut off ( keV) and implying a small optical
depth (). The new observations confirm the previously witnessed trend
of exhibiting strong Fe K absorption in the soft state, that significantly
weakens during the hard state. Optical (GROND) and radio (GMRT) observations
suggest for AX J1745.6-2901 a standard broad band SED as typically observed in
accreting neutron stars.Comment: Accepted for publication in MNRA
Mass discrimination using double-sided silicon microstrip detectors for pions and protons at intermediate energies
Prototype silicon detector modules for the vertex detector of the FINUDA experiment were tested at TRIUMF using pions and protons at 270 and 408 MeV/c in order to study their use for mass discrimination based on energy deposition. The detector modules were constructed using double-sided silicon detectors based on the ALEPH design, read out by VA1 integrated circuits. The test modules and apparatus are described, details of the data analysis are discussed, and the results are presented together with GEANT simulations. Particular attention is given to the detector response for the various particles, with signals ranging from the minimum-ionising pions at 408 MeV/c up to 20 times minimum-ionising for the protons at 270 MeV/c. ( 1999 Elsevier Science B.V. All rights reserved
Fertilizer type influences tomato yield and soil N2O emissions
Improvements in crop management for a more sustainable agriculture are fundamental to reduce environmental impacts of cropland and to mitigate effects on global climate change. In this study three fertilization types – ammonium nitrate (control); mineral fertilizer added with a nitrification inhibitor (3,4-dimethylpyrazole phosphate (DMPP)), and an organo-mineral fertilizer (OM) – were tested on a tomato crop in order to evaluate effects both on crop production and soil N2O emissions. Plants grown under OM fertilization had a greater relative growth rate compared to mineral fertilization, due to a higher net assimilation rate, which was related to a greater light interception rather than to a higher photosynthetic efficiency. OM fertilization determined the highest fruit production and lower soil N2O fluxes compared to NH4NO3, although the lowest soil N2O fluxes were found in response to mineral fertilizer added with a nitrification inhibitor. It can be concluded that organo-mineral fertilizer is a better nutrient source compared to mineral fertilizers able to improve crop yield and to mitigate soil N2O emission
PAMELA's measurements of geomagnetic cutoff variations during solar energetic particle events
Data from the PAMELA satellite experiment were used to measure the
geomagnetic cutoff for high-energy ( 80 MeV) protons during the solar
particle events on 2006 December 13 and 14. The variations of the cutoff
latitude as a function of rigidity were studied on relatively short timescales,
corresponding to single spacecraft orbits (about 94 minutes). Estimated cutoff
values were cross-checked with those obtained by means of a trajectory tracing
approach based on dynamical empirical modeling of the Earth's magnetosphere. We
find significant variations in the cutoff latitude, with a maximum suppression
of about 6 deg for 80 MeV protons during the main phase of the storm. The
observed reduction in the geomagnetic shielding and its temporal evolution were
compared with the changes in the magnetosphere configuration, investigating the
role of IMF, solar wind and geomagnetic (Kp, Dst and Sym-H indexes) variables
and their correlation with PAMELA cutoff results.Comment: Conference: The 34th International Cosmic Ray Conference (ICRC2015),
30 July - 6 August, 2015, The Hague, The Netherlands, Volume:
PoS(ICRC2015)28
First determination of the one-proton induced Non-Mesonic Weak Decay width of p-shell {\Lambda}-Hypernuclei
Previous studies of proton and neutron spectra from Non-Mesonic Weak Decay of
eight Lambda-Hypernuclei (A = 5-16) have been revisited. New values of the
ratio of the two-nucleon and the one-proton induced decay widths,
Gamma_2N/Gamma_p, are obtained from single proton spectra, Gamma_2N/Gamma_p =
0.50 +/- 0.24, and from neutron and proton coincidence spectra,
Gamma_2N/Gamma_p = 0.36 +/- 0.14stat +0.05sys -0.04sys , in full agreement with
previously published ones. With these values, a method is developed to extract
the one-proton induced decay width in units of the free Lambda decay width,
Gamma_p/Gamma_Lambda, without resorting to Intra Nuclear Cascade models but by
exploiting only experimental data, under the assumption of a linear dependence
on A of the Final State Interaction contribution. This is the first systematic
determination ever done and it agrees within the errors with recent theoretical
calculations.Comment: 16 pages, 3 figures, 2 table
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