643 research outputs found
An intermolecular dative B←N bond in 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3-thiazole
The title compound, C9H14BNO2S, is in an unusual bend conformation and the B atom of one molecule within the crystal forms an intermolecular dative bond with the N atom of a neighbouring molecule, an infrequent phenomenon in boronic derivative crystals
tert-Butyl 6-bromo-1,4-dimethyl-9H-carbazole-9-carboxylate
The title compound, C19H20BrNO2, consists of a carbazole skeleton with methyl groups at positions 1 and 4, a protecting group located at the N atom and a Br atom at position 6. The pyrrole ring is oriented at dihedral angles of 1.27 (7) and 4.86 (7)° with respect to the adjacent benzene rings. The dihedral angle between the benzene rings is 5.11 (7). The crystal structure is determined mainly by intramolecular C—H⋯O and intermolecular π–π interactions. π-stacking between adjacent molecules forms columns with a parallel arrangement of the carbazole ring systems. The presence of the tert-butoxycarbonyl group on the carbazole N atom and the intramolecular hydrogen bond induce a particular conformation of the exocyclic N—C bond within the molecule
Search for 22Na in novae supported by a novel method for measuring femtosecond nuclear lifetimes
Classical novae are thermonuclear explosions in stellar binary systems, and important sources of 26Al and 22Na. While ¿ rays from the decay of the former radioisotope have been observed throughout the Galaxy, 22Na remains untraceable. Its half-life (2.6 yr) would allow the observation of its 1.275 MeV ¿-ray line from a cosmic source. However, the prediction of such an observation requires good knowledge of its nucleosynthesis. The 22Na(p,¿¿)23Mg reaction remains the only source of large uncertainty about the amount of 22Na ejected. Its rate is dominated by a single resonance on the short-lived state at 7785.0(7) keV in 23Mg. Here, we propose a combined analysis of particle-particle correlations and velocity-difference profiles to measure femtosecond nuclear lifetimes. The application of this method to the study of the 23Mg states, places strong limits on the amount of 22Na produced in novae and constrains its detectability with future space-borne observatories.Postprint (published version
Assessment of diversity of native species produced in forest nurseries of Rio de Janeiro State
AbstractThe objective of this paper was to evaluate the diversity of native species produced by nurseries in the State of Rio de Janeiro. The diagnostic and survey were conducted during the months of February, March and April of the year 2010, the research included all nurseries that produced seedlings of Atlantic Forest species. The fieldwork consisted of visits to the 70 surveyed nurseries, in which a list of the species produced in the nursery was requested and the seedling production manager was interviewed, filling in a questionnaire covering various topics related to seedlings production. We observed 277 forest species native from the Atlantic Forest produced in the nurseries. In average, the nurseries produce 56 different native species. The total diversity of native species produced in the State of Rio de Janeiro is low, as well as the mean diversity, since more than half of the nurseries work with a list of 50 or fewer species, what is insufficient considering the diversity of forest species that occur in the different vegetation types of the state.Keywords: Forest seedlings; forest restoration; Atlantic Forest.O objetivo deste trabalho foi avaliar a diversidade de espécies florestais nativas produzidas nos viveiros do estado do Rio de Janeiro. O levantamento e diagnóstico foram realizados durante os meses de fevereiro, março e abril de 2010, sendo incluídos os viveiros que produziam mudas de espécies florestais da Mata Atlântica. O trabalho de campo consistiu em visitas a 70 viveiros florestais, nos quais foi requerida a lista das espécies produzidas e realizada entrevista com o responsável, sendo preenchido um questionário englobando diversos temas relacionados à produção de mudas. Foram observadas 277 espécies florestais nativas da Mata Atlântica sendo produzidas nos viveiros, que, em média, trabalham com 56 espécies nativas. A diversidade total de espécies florestais da Mata Atlântica produzidas nos viveiros do Estado do Rio de Janeiro é baixa, assim como a diversidade média, já que mais da metade dos viveiros trabalha com uma listagem de 50 ou menos espécies, número insuficiente considerando a diversidade de espécies florestais presentes nas diferentes formações vegetais do estado.Palavras-chave: Mudas florestais; restauração florestal; Mata Atlântica. AbstractAssessment of diversity of native species produced in forest nurseries of Rio de Janeiro State. The objective of this paper was to evaluate the diversity of native species produced by nurseries in the State of Rio de Janeiro. The diagnostic and survey were conducted during the months of February, March and April of the year 2010, the research included all nurseries that produced seedlings of Atlantic Forest species. The fieldwork consisted of visits to the 70 surveyed nurseries, in which a list of the species produced in the nursery was requested and the seedling production manager was interviewed, filling in a questionnaire covering various topics related to seedlings production. We observed 277 forest species native from the Atlantic Forest produced in the nurseries. In average, the nurseries produce 56 different native species. The total diversity of native species produced in the State of Rio de Janeiro is low, as well as the mean diversity, since more than half of the nurseries work with a list of 50 or fewer species, what is insufficient considering the diversity of forest species that occur in the different vegetation types of the state.Keywords: Forest seedlings; forest restoration; Atlantic Forest
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
A Lei da Mediação de Conflitos: estudos sobre a sua aplicação
Financiamento de MEDLaw - FCT UIDB/04112/2020.Os dez anos de vigência da Lei da Mediação em Portugal constituíram o mote para a compilação nesta obra de diversos estudos empírico-dogmáticos sobre a sua aplicação, analisando-se questões prementes como a voluntariedade ou obrigatoriedade da mediação, a executoriedade do acordo de mediação e a Convenção de Singapura, as exigências processuais e a suspensão dos prazos de prescrição e caducidade com o recurso à mediação, a organização associativa dos mediadores e a importância da sua formação, o funcionamento dos sistemas públicos de mediação, bem como novas áreas de aplicação da mediação, em especial no domínio administrativo e na recuperação extrajudicial de empresas, e ainda a relevância do desenvolvimento científico sobre este meio de resolução de conflitos.
Ao regulamentar num único diploma, pela primeira vez no nosso ordenamento jurídico, a mediação pública e privada, a Lei n.º 29/2013, de 19 de abril, constituiu um marco legislativo. Dez anos volvidos, importava refletir sobre a sua aplicação prático-jurídica, norteados pelo objetivo de promover o estudo e a efetiva implementação da mediação de conflitos em Portugal. Esta obra constitui o output desenvolvido no âmbito do projeto de investigação MEDLAW, com o apoio da Fundação para a Ciência e Tecnologia, no âmbito do financiamento base atribuído ao polo de Leiria do Instituto Jurídico Portucalense, com a ref. UIDB/04112/2020.info:eu-repo/semantics/publishedVersio
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