127 research outputs found
VUV/EUV ionising radiation and atoms and ions: dual laser plasma investigations
The interaction of ionising radiation with atoms and ions is a key fundamental process. This report concentrates on studies of photoexcitation/photoionisation using laser-produced plasmas as continuum sources and synchronised laser plasma plumes to provide the absorbing atom or ion species. Examples from studies of the interaction of ionising radiation with atoms and ions ranging from few-electron atomic and ionic systems to the many-electron high atomic number actinides are reviewed and illustrate the advantages and limitations of the Dual Laser Plasma technique
Exact spectra, spin susceptibilities and order parameter of the quantum Heisenberg antiferromagnet on the triangular lattice
Exact spectra of periodic samples are computed up to .
Evidence of an extensive set of low lying levels, lower than the softest
magnons, is exhibited.
These low lying quantum states are degenerated in the thermodynamic limit;
their symmetries and dynamics as well as their finite-size scaling are strong
arguments in favor of N\'eel order.
It is shown that the N\'eel order parameter agrees with first-order spin-wave
calculations. A simple explanation of the low energy dynamics is given as well
as the numerical determinations of the energies, order parameter and spin
susceptibilities of the studied samples. It is shown how suitable boundary
conditions, which do not frustrate N\'eel order, allow the study of samples
with spins.
A thorough study of these situations is done in parallel with the more
conventional case .Comment: 36 pages, REVTeX 3.0, 13 figures available upon request, LPTL
preprin
Prioritizing global land protection for population persistence can double the efficiency of habitat protection for reducing mammal extinction risk
Halting the alarming rate of species extinction, driven primarily by habitat destruction, motivated the international community to adopt the Global Biodiversity Framework (2022) and its targets aimed at reversing habitat and species loss. Because of urgency and resource constraints, a key challenge is meeting targets effectively and efficiently. Here we conduct a global prioritization linking 70,492 unique population maps and life history characteristics for 861 threatened terrestrial mammal species. Incorporating individual population data to identify priority areas for conservation nearly doubled the likely long-term persistence of species for the same amount of land compared with a typical approach based on species distributions alone. We map and rank global mammal persistence priority areas and assess how well the current protected area (PA) system captures these important regions. Our results offer a clearer, quantifiable link between conservation actions and global extinction risk than previously possible at a global scale
Trends in autoionization of Rydberg states converging to the 4s threshold in the Kr-Rb⁺-Sr²⁺ isoelectonic sequence: theory and experiment
We have measured the photoabsorption spectra of the Kr-like ions Rb+ and Sr2+ at photon energies corresponding to the excitation of 4s-np resonances using, the dual laser plasma photoabsorption technique. Dramatic changes in the line profiles, with increasing ionization and also proceeding along the Rydberg series of each ion, are observed and explained by the trends in 4s-transition amplitudes computed within a framework of configuration-interaction Pauli-Fock calculations. Total photoionization cross sections show very good agreement with relative absorption data extracted from the measured spectra
Nutrition in agricultural development: The case of irrigated rice cultivation in West Kenya
ASC – Publicaties niet-programma gebonde
Características sensoriais, físicas e químicas e aceitação de arroz irrigado ou de terras altas
Resumo:O objetivo deste trabalho foi caracterizar química, física e sensorialmente três genótipos de arroz polido de cultivo irrigado e cinco de terras altas. Determinaram-se: a composição centesimal, o amido, a amilose, a temperatura de gelatinização (Tg), a absorção de água ao cozimento, a cor, a textura instrumental, o perfil sensorial e a aceitação de atributos. A composição centesimal e o teor de amido variaram entre os genótipos. O 'Moti' e a linhagem N2583 foram classificados como cerosos, 'Douradão' apresentou amilose muito baixa, e os demais genótipos, amilose baixa. 'Irga 417', 'Moti' e AB101002 apresentaram Tg baixa; 'Douradão', alta; e os demais, intermediária. O 'Moti' e a linhagem N2583 crus apresentaram os maiores valores de L*; no entanto, após o cozimento, esses valores diminuíram e foram idênticos em todos os genótipos. 'Arroz-da-terra' apresentou maior a*, 'BRS Primavera' e N2583 apresentaram maior b*; e após o cozimento, houve redução desses valores. Na análise sensorial, destacaram-se 'AN Cambará', por pontos escuros e formato alongado; AB101002, 'Irga 417' e 'BRS Primavera', pela firmeza, cor branca e grãos soltos, que foram bem aceitos; e o 'Moti', por ser pegajoso, macio e com brilho, foi o menos aceito. Os atributos sensoriais do arroz são mais associados a características químicas, intrínsecas ao genótipo, do que à atribuição de plantio a terras altas ou irrigadas
Study of Z → llγ decays at √s = 8 TeV with the ATLAS detector
This paper presents a study of Z → llγ decays
with the ATLAS detector at the Large Hadron Collider. The
analysis uses a proton–proton data sample corresponding to
an integrated luminosity of 20.2 fb−1 collected at a centre-ofmass energy √s = 8 TeV. Integrated fiducial cross-sections
together with normalised differential fiducial cross-sections,
sensitive to the kinematics of final-state QED radiation, are
obtained. The results are found to be in agreement with stateof-the-art predictions for final-state QED radiation. First
measurements of Z → llγ γ decays are also reported
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