4,416 research outputs found
A Comparison of c-CâHâ and l-CâHâ in the Spiral Arm Clouds
Using the IRAM 30-m telescope, we observed molecular absorption lines from c-CâHâ produced in diffuse clouds toward the high-mass star forming regions W51 e1/e2 and W49N to determine the abundance ratio between the cyclic and linear isomers of CâHâ (N_c/N_l). The abundance ratio is found to be 3-5 in the sources where l-CâHâ was previously detected. A possible source of uncertainty in the determination of N_c/N_l is related to the estimate of N(c-CâHâ). The main goal of this paper is verification of this hypothesis
The Impact of Extreme Weather Events on Budget Balances and Implications for Fiscal Policy.
This paper explores implications of climate change for fiscal policy by assessing the impact of large scale extreme weather events on changes in public budgets. We apply alternative measures for large scale extreme weather events and conclude that the budgetary impact of such events ranges between 0.23% and 1.1% of GDP depending on the country group. Developing countries face a much larger effect on changes in budget balances following an extreme weather event than do advanced economies. Based on these findings, we discuss implications for fiscal policy and publicly-provided disaster insurance. Our policy conclusions point to the enhanced need to reach and maintain sound fiscal positions given that climate change is expected to cause an increase in the frequency and severity of natural disasters. JEL Classification: Q54, Q58, F59, H87.Global warming, climate change, fiscal sustainability, disasters.
Water production in comet 81P/Wild 2 as determined by Herschel/HIFI
The high spectral resolution and sensitivity of Herschel/HIFI allows for the detection of multiple rotational water lines and accurate determinations
of water production rates in comets. In this Letter we present HIFI observations of the fundamental 1_(10)â1_(01) (557 GHz) ortho and 1_(11)â0_(00)
(1113 GHz) para rotational transitions of water in comet 81P/Wild 2 acquired in February 2010. We mapped the extent of the water line emission
with five point scans. Line profiles are computed using excitation models which include excitation by collisions with electrons and neutrals and
solar infrared radiation. We derive a mean water production rate of 1.0 Ă 10^(28) molecules s^(â1) at a heliocentric distance of 1.61 AU about 20 days
before perihelion, in agreement with production rates measured from the ground using observations of the 18-cm OH lines. Furthermore, we
constrain the electron density profile and gas kinetic temperature, and estimate the coma expansion velocity by fitting the water line shapes
HIFI observations of water in the atmosphere of comet C/2008 Q3 (Garradd)
High-resolution far-infrared and sub-millimetre spectroscopy of water lines is an important tool to understand the physical and chemical properties of cometary atmospheres.We present observations of several rotational ortho- and para-water transitions in comet C/2008 Q3 (Garradd) performed with HIFI on Herschel. These observations have provided the first detection of the 2_(12)â1_(01) (1669 GHz) ortho and 1_(11)â0_(00) (1113 GHz) para transitions of water in a cometary spectrum. In addition, the ground-state transition 1_(10)â1_(01) at 557 GHz is detected and mapped. By detecting several water lines quasi-simultaneously and mapping their emission we can constrain the excitation parameters in the coma. Synthetic line profiles are computed using excitation models which include excitation by collisions, solar infrared radiation, and radiation trapping. We obtain the gas kinetic temperature, constrain the electron density profile, and estimate the coma expansion velocity by analyzing the map and line shapes. We derive water production rates of 1.7â2.8 Ă 10^(28) s^(â1) over the range r_h = 1.83â1.85 AU
Submillimeter Imaging of NGC 891 with SHARC
The advent of submillimeter wavelength array cameras operating on large
ground-based telescopes is revolutionizing imaging at these wavelengths,
enabling high-resolution submillimeter surveys of dust emission in star-forming
regions and galaxies. Here we present a recent 350 micron image of the edge-on
galaxy NGC 891, which was obtained with the Submillimeter High Angular
Resolution Camera (SHARC) at the Caltech Submillimeter Observatory (CSO). We
find that high resolution submillimeter data is a vital complement to shorter
wavelength satellite data, which enables a reliable separation of the cold dust
component seen at millimeter wavelengths from the warmer component which
dominates the far-infrared (FIR) luminosity.Comment: 4 pages LaTeX, 2 EPS figures, with PASPconf.sty; to appear in
"Astrophysics with Infrared Surveys: A Prelude to SIRTF
Observations of pre-stellar cores
Our understanding of the physical and chemical structure of pre-stellar
cores, the simplest star-forming sites, has significantly improved since the
last IAU Symposium on Astrochemistry (South Korea, 1999). Research done over
these years has revealed that major molecular species like CO and CS
systematically deplete onto dust grains at the interior of pre-stellar cores,
while species like N2H+ and NH3 survive in the gas phase and can usually be
detected towards the core centers. Such a selective behaviour of molecular
species gives rise to a differentiated (onion-like) chemical composition, and
manifests itself in molecular maps as a dichotomy between centrally peaked and
ring-shaped distributions. From the point of view of star-formation studies,
the identification of molecular inhomogeneities in cores helps to resolve past
discrepancies between observations made using different tracers, and brings the
possibility of self-consistent modelling of the core internal structure. Here I
present recent work on determining the physical and chemical structure of two
pre-stellar cores, L1498 and L1517B, using observations in a large number of
molecules and Monte Carlo radiative transfer analysis. These two cores are
typical examples of the pre-stellar core population, and their chemical
composition is characterized by the presence of large freeze out holes in most
molecular species. In contrast with these chemically processed objects, a new
population of chemically young cores has started to emerge. The characteristics
of its most extreme representative, L1521E, are briefly reviewed.Comment: 10 pages, 5 figures. To appear in IAU 231 conf. proc.
"Astrochemistry: Recent Successes and Current Challenges," eds. D.C. Lis,
G.A. Blake, and E. Herbs
Digital Marketing System for Fishery Industry Products (literature review)
Conduct a literature study regarding digital marketing of fisheries industry products in Indonesia. The advantages gained when marketing fisheries product commodities online include being efficient in terms of time, costs and energy for carrying out promotions. The online system can be accessed by anyone, anytime and anywhere so it can be used as a very massive promotional event. Apart from that, entrepreneurs and consumers of fishery products can be closer even though they are very far away. Besides that, with the existence of an online marketing system, the credibility of the fisheries commodity business is considered more promising in the eyes of consumers. To carry out digital marketing, it is necessary to increase public knowledge of Information and Communication Technology (ICT)
Non-Backtracking Loop Soups and Statistical Mechanics on Spin Networks
We introduce and study a Markov field on the edges of a graph in dimension â„ 2 whose configurations are spin networks. The field arises naturally as the edge-occupation field of a Poissonian model (a soup) of non-backtracking loops and walks characterized by a spatial Markov property such that, conditionally on the value of the edge-occupation field on a boundary set that splits the graph into two parts, the distributions of the loops and arcs contained in the two parts are independent of each other. The field has a Gibbs distribution with a Hamiltonian given by a sum of terms which involve only edges incident on the same vertex. Its free energy density and other quantities can be computed exactly, and their critical behavior analyzed, in any dimension.The first author acknowledges the support of Vidi Grant 639.032.916 of the Netherlands Organization for Scientific Research (NWO). The second author was partially supported by the Knut and Alice Wallenberg Foundation.This is the final version of the article. It first appeared from Springer via https://doi.org/10.1007/s00023-016-0524-
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