6,921 research outputs found
ALMA and VLA observations of recombination lines and continuum toward the Becklin-Neugebauer object in Orion
Compared to their centimeter-wavelength counterparts, millimeter
recombination lines (RLs) are intrinsically brighter and are free of pressure
broadening. We report observations of RLs (H30alpha at 231.9 GHz, H53alpha at
42.9 GHz) and the millimeter and centimeter continuum toward the
Becklin-Neugebauer (BN) object in Orion, obtained from the Atacama Large
Millimeter/submillimeter Array (ALMA) Science Verification archive and the Very
Large Array (VLA). The RL emission appears to be arising from the
slowly-moving, dense (Ne=8.4x10^6 cm^-3) base of the ionized envelope around
BN. This ionized gas has a relatively low electron temperature (Te<4900 K) and
small (<<10 km s^-1) bulk motions. Comparing our continuum measurements with
previous (non)detections, it is possible that BN has large flux variations in
the millimeter. However, dedicated observations with a uniform setup are needed
to confirm this. From the H30alpha line, the central line-of-sight LSR velocity
of BN is 26.3 km s^-1.Comment: To appear in Astronomy and Astrophysics as a Letter to the editor.
Corrections to mm fluxes. Discussion about flux variability shortened.
Physical properties of ionized gas remain the same. Table 1 to main text
rather than online only. Language edite
Black Rings in (Anti)-deSitter space
We construct solutions for thin black rings in Anti-deSitter and deSitter
spacetimes using approximate methods. Black rings in AdS exist with arbitrarily
large radius and satisfy a bound |J| \leq LM, which they saturate as their
radius becomes infinitely large. For angular momentum near the maximum, they
have larger area than rotating AdS black holes. Thin black rings also exist in
deSitter space, with rotation velocities varying between zero and a maximum,
and with a radius that is always strictly below the Hubble radius. Our general
analysis allows us to include black Saturns as well, which we discuss briefly.
We present a simple physical argument why supersymmetric AdS black rings must
not be expected: they do not possess the necessary pressure to balance the AdS
potential. We discuss the possible existence or absence of `large AdS black
rings' and their implications for a dual hydrodynamic description. An analysis
of the physical properties of rotating AdS black holes is also included.Comment: 38 pages, 6 figures. v2: changes in terminology, refs added. v3:
minor improvements, refs added, published versio
La función de la imaginación en las Coronas de Rodolfo Usigli
La función de la imaginación en las Coronas de Rodolfo Usigl
The Foundational Process of Cities in Spanish America: The Law of Indies as a Planning Tool for Urbanization in Early Colonial Towns in Venezuela
This essay analyzes the criteria used by the Law of Indies in the settlement of towns in Spanish Latin America using the city of Barcelona, Venezuela, as a case study. This is the first scholarly analysis of the historical evolution of the city´s physical structure, and it will help advance the research methods in planning history education
Estudo experimental do comportamento ocular em trabalhadores administrativos como um indicador de conforto visual em situação de risco de encadeamento
The daylight impact on the visual environment is fundamental on visual display terminal work (VDT). Visual performance and visual comfort should be considered for equal. The study (n=16) was performed at the experimental lighting laboratory. Office work with VDT was evaluated using STROOP task in two orientations: (with/without solar presence in the visual field). Our hypothesis states the existence of a relationship between ocular behavior and visual comfort of workers. An eye-tracker was employed in order to record the ocular gestural parameters: blinks, direction of gaze, eye aperture (Degree of eye?s openness) and pupil size, which were correlated with the vertical illuminance at the eye. Visual comfort was assessed with Glare Sensation Vote. Results indicate a strong negative linear correlation between eye illuminance and the degree of eye?s openness in the direct sunlight scenario (p=-0.636; s=0.008) and in diffuse light scenario (p=-0.661; s=0.005), that could be the main predictor of visual discomfort. This experiment allowed us to explore eye behavior patterns that could be visual comfort indices under glare risk situations.O impacto a luz do dia no ambiente visual é fundamental para o trabalho no Ecrã de
Visualização de Dados (EDV). Desempenho visual e conforto visual devem ser considerados em igual. O estudo (n = 16) foi realizado no laboratório experimental de iluminação. O trabalho de escritório com EDV foi avaliado utilizando a tarefa de Stroop em duas orientações: (com / sem presença solar no campo visual). A nossa hipótese afirma a existência de uma relação entre o comportamento ocular e
conforto visual dos trabalhadores. Um “eye-tracker” foi desenvolvido para gravar os parâmetros gestuais oculares: pestanejar, direção do olhar, abertura dos olhos (Grau de abertura do olho) e tamanho da pupila, que foram correlacionados com a iluminância vertical no olho. Conforto visual foi avaliado com a escala de sensação de encadeamento. Os resultados indicam uma correlação linear negativa forte entre a luminosidade dos olhos e do grau de abertura de olho no cenário de luz solar
direta (p = -0,636; s = 0,008) e no cenário de luz difusa (p = -0,661; s = 0,005), que poderia ser o principal preditor de desconforto visual. Esta experiência permitiu-nos explorar padrões de comportamento do olho que poderiam ser os índices de conforto visual em situação de risco de encadeamento.Fil: Yamin Garretón, Julieta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Rodriguez, Roberto Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Pattini, Andrea Elvira. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentin
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