736 research outputs found
Gravitational wave recoils in non-axisymmetric Robinson-Trautman spacetimes
We examine the gravitational wave recoil waves and the associated net kick
velocities in non-axisymmetric Robinson-Trautman spacetimes. We use
characteristic initial data for the dynamics corresponding to non-head-on
collisions of black holes. We make a parameter study of the kick distributions,
corresponding to an extended range of the incidence angle in the
initial data. For the range of examined () the kick distributions as a function of the symmetric mass
parameter satisfy a law obtained from an empirical modification of the
Fitchett law, with a parameter that accounts for the non-zero net
gravitational momentum wave fluxes for the equal mass case. The law fits
accurately the kick distributions for the range of examined, with a
rms normalized error of the order of . For the equal mass case the
nonzero net gravitational wave momentum flux increases as increases,
up to beyond which it decreases. The maximum net
kick velocity is about for for the boost parameter considered.
For the distribution is a monotonous function of
. The angular patterns of the gravitational waves emitted are examined.
Our analysis includes the two polarization modes present in wave zone
curvature.Comment: 10 pages, 5 figures. arXiv admin note: substantial text overlap with
arXiv:1403.4581, arXiv:1202.1271, arXiv:1111.122
Effectiveness and management of Conservation Units in the west and northwest regions of Paraná (Brazil)
The implementation of conservation units is an important strategy to conserve biodiversity, however, their consolidation as an effective mechanism for protecting natural resources faces several challenges. Therefore, the objective of this work was to evaluate the effectiveness and management of nine conservation units in the west and northwest regions of the state of Paraná, Brazil, by application of questionnaires, and interviews with managers in these areas. All evaluated conservation units had insufficient number of employees to meet their demand, and the management plan of 56% of the 89% units that had a management plan were outdated. According to the adopted criteria to evaluate the effectiveness of these conservation units, 67% of them presented satisfactory implementation effectiveness, and management conditions, because they have minimally fulfilled their objectives, despite the several economic, political and social barriers.The implementation of conservation units is an important strategy to conserve biodiversity, however, their consolidation as an effective mechanism for protecting natural resources faces several challenges. Therefore, the objective of this work was to evaluate the effectiveness and management of nine conservation units in the west and northwest regions of the state of Paraná, Brazil, by application of questionnaires, and interviews with managers in these areas. All evaluated conservation units had insufficient number of employees to meet their demand, and the management plan of 56% of the 89% units that had a management plan were outdated. According to the adopted criteria to evaluate the effectiveness of these conservation units, 67% of them presented satisfactory implementation effectiveness, and management conditions, because they have minimally fulfilled their objectives, despite the several economic, political and social barriers
Libraries and librarians as coadjutants in the editorial process of scientific publications - reaffirming a proposal
Homeopatia e fitoterapia: crenças e consumo dos estudantes da Escola Superior de Tecnologia da Saúde de Lisboa
Medicinas complementares e alternativas (MCA): cada vez mais utilizadas, em paralelo com a medicina convencional (MC) e 80% das pessoas no mundo já usaram alguma terapia das MCA. Insatisfação relativa à MC: preço elevado da assistência médica privada; alto custo dos medicamentos; precariedade da assistência prestada pelos serviços públicos. Crenças positivas sobre MCA: tão eficazes como a MC; se correctamente utilizadas, não ocasionam efeitos colaterais prejudiciais; mais compatíveis com valores pessoais e filosofias religiosas do que MC. Utilização das MCA: mais utilizadas (homeopatia e fitoterapia); tratamento e controlo de doenças crónicas. Objectivo do estudo: caracterizar as crenças sobre homeopatia e fitoterapia e os comportamentos de consumo dos estudantes da ESTeSL, enquanto consumidores e futuros profissionais de saúde
Profile of patients admitted to the intensive care unit after exogenous intoxication at a university hospital
- …