573 research outputs found
SiS in the circumstellar envelope of IRC +10126: maser and quasi-thermal emission
We present new Effelsberg-100 m, ATCA, and VLA observations of rotational SiS
transitions in the circumstellar envelope (CSE) of IRC +10216. Thanks to the
high angular resolution achieved by the ATCA observations, we unambiguously
confirm that the molecule's J=1-0 transition exhibits maser action in this CSE,
as first suggested more than thirty years ago. The maser emission's radial
velocity peaking at a local standard of rest velocity of -39.8620.065 km/s
indicates that it arises from an almost fully accelerated shell. Monitoring
observations show time variability of the SiS (1-0) maser. The two lowest-
SiS quasi-thermal emission lines trace a much more extended emitting region
than previous high-J SiS observations. Their distributions show that the SiS
quasi-thermal emission consists of two components: one is very compact
(radius<1.5", corresponding to <3 cm), and the other extends
out to a radius >11". An incomplete shell-like structure is found in the
north-east, which is indicative of existing SiS shells. Clumpy structures are
also revealed in this CSE. The gain of the SiS (1-0) maser (optical depths of
about -5 at the blue-shifted side and, assuming inversion throughout the entire
line's velocity range, about -2 at the red-shifted side) suggests that it is
unsaturated. The SiS (1-0) maser can be explained in terms of ro-vibrational
excitation caused by infrared pumping, and we propose that infrared continuum
emission is the main pumping source.Comment: Accepted for publication in ApJ. A high-resolution version can be
found at https://gongyan2444.github.io/pdf/cw-leo-sis.pdf 3D movies of SiS
cubes can be found at https://gongyan2444.github.io/movie/sis10-3d.avi and
https://gongyan2444.github.io/movie/sis21-3d.av
Ăkologische Untersuchungen zur Nitrifikation in Nord-und Ostsee
Ammonia, nitrite and nitrate were regularly estimated at several stations in the Kieler Bucht (western Baltic Sea) since November 1964. There are considerable seasonal changes in the contents of these 3 nitrogen compounds with impressive maxima of nitrite and nitrate in February or at the beginning of March. The great increase of nitrite and nitrate during the winter and also a smaller increase in summer are mainly caused by oxidation of ammonia, first to nitrite and then to nitrate, by nitrifying bacteria. In consequence chemoautotrophic nitrite- and nitratebacteria could be found in the water as well as in sediments all over the Kieler Bucht and also in the North Sea around the isle of Helgoland. These nitrifying bacteria are able to oxidize ammonia or nitrite in salinity conditions typical for the western Baltic Sea and the North Sea
PegfilgrastimâÂąâciprofloxacin for primary prophylaxis with TAC (docetaxel/doxorubicin/cyclophosphamide) chemotherapy for breast cancer. Results from the GEPARTRIO study
Background: TAC (docetaxel/doxorubicin/cyclophosphamide) is associated with high incidences of grade 4 neutropenia and febrile neutropenia (FN). This analysis compared the efficacies of four regimens for primary prophylaxis of FN and related toxic effects in breast cancer patients receiving neoadjuvant TAC. Patients and methods: Patients with stage T2-T4 primary breast cancer were scheduled to receive 6-8 cycles of TAC. Primary prophylaxis was: ciprofloxacin 500 mg orally twice daily on days 5-14 (nâ=â253 patients; 1478 cycles), daily granulocyte colony-stimulating factor (G-CSF) (filgrastim 5 Îźg/kg/day or lenograstim 150 Îźg/m2/day) on days 5-10 (nâ=â377; 2400 cycles), pegfilgrastim 6 mg on day 2 (nâ=â305; 1930 cycles), or pegfilgrastim plus ciprofloxacin (nâ=â321; 1890 cycles). Results: Pegfilgrastim with/without ciprofloxacin was significantly more effective than daily G-CSF or ciprofloxacin in preventing FN (5% and 7% versus 18% and 22% of patients; all Pâ<â0.001), grade 4 neutropenia, and leukopenia. Pegfilgrastim plus ciprofloxacin completely prevented first cycle FN (Pâ<â0.01 versus pegfilgrastim alone) and fatal neutropenic events. Conclusion: Ciprofloxacin alone, or daily G-CSF from day 5-10 (as in common practice), provided suboptimal protection against FN and related toxic effects in patients receiving TAC. Pegfilgrastim was significantly more effective in this setting, especially if given with ciprofloxaci
Submarine groundwater springs are characterized by distinct fish communities
The inflow of terrestrial groundwater into the ocean is increasingly recognized as an important local source of nutrients and pollutants to coastal ecosystems. Although there is evidence of a link between fresh submarine groundwater discharge (SGD)âderived nutrients and primary producer and primary consumer abundances, the effects of fresh SGD on the productivity of higher trophic levels such as ichthyofaunal communities remain unclear. To further investigate this relationship, we sampled three sites inside a coral reef lagoon in Mauritius: One site entailing six distinct groundwater springs, a site highly influenced by freshwater influx through the springs, and a strictly marine control site. Using remote underwater video surveys, we found that fish abundances were significantly higher at the groundwater springs than at the other two sampling sites.Principal component analyses showed that the springs and the springâinfluenced part of the lagoon were best described by elevated water nutrient loadings, whereas the control site was characterized by higher water salinity and pH. Macroalgae cover was highest at the control site and the springs. Herbivores and invertivores dominated the fish community at the springs, in contrast to generalists at the control site. At the springâinfluenced site, we mainly encountered high coral/turf algae cover and high abundances of associated fish feeding groups (territorial farmers, corallivores). Our results provide evidence of a fresh SGDâdriven relationship between altered hydrography and distinct fish communities with elevated abundances at groundwater springs in a coral reef lagoon. These findings suggest that the management and assessment of secondary consumer productivity in tropical lagoons should take into account the effects of groundwater springs
Bayesian D-Optimal Choice Designs for Mixtures
__Abstract__
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\nConsumer products and services can often be described as mixtures of ingredients. Examples are the mixture of ingredients in a cocktail and the mixture of different components of waiting time (e.g., in-vehicle and out-of-vehicle travel time) in a transportation setting. Choice experiments may help to determine how the respondents\' choice of a product or service is affected by the combination of ingredients. In such studies, individuals are confronted with sets of hypothetical products or services and they are asked to choose the most preferred product or service from each set.
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\nHowever, there are no studies on the optimal design of choice experiments involving mixtures. We propose a method for generating an optimal design for such choice experiments. To this end, we first introduce mixture models in the choice context and next present an algorithm to construct optimal experimental designs, assuming the multinomial logit model is used to analyze the choice data. To overcome the problem that the optimal designs depend on the unknown parameter values, we adopt a Bayesian D-optimal design approach. We also consider locally D-optimal designs and compare the performance of the resulting designs to those produced by a utility-neutral (UN) approach in which designs are based on the assumption that individuals are indifferent between all choice alternatives. We demonstrate that our designs are quite different and in general perform better than the UN designs
Use of secondary sewage water as a culture medium for Chaetoceros gracilis and Thalassiosira Sp (Chrysophyceae) in laboratory conditions
Deep-Sea Origin and In-Situ Diversification of Chrysogorgiid Octocorals
The diversity, ubiquity and prevalence in deep waters of the octocoral family Chrysogorgiidae Verrill, 1883 make it noteworthy as a model system to study radiation and diversification in the deep sea. Here we provide the first comprehensive phylogenetic analysis of the Chrysogorgiidae, and compare phylogeny and depth distribution. Phylogenetic relationships among 10 of 14 currently-described Chrysogorgiidae genera were inferred based on mitochondrial (mtMutS, cox1) and nuclear (18S) markers. Bathymetric distribution was estimated from multiple sources, including museum records, a literature review, and our own sampling records (985 stations, 2345 specimens). Genetic analyses suggest that the Chrysogorgiidae as currently described is a polyphyletic family. Shallow-water genera, and two of eight deep-water genera, appear more closely related to other octocoral families than to the remainder of the monophyletic, deep-water chrysogorgiid genera. Monophyletic chrysogorgiids are composed of strictly (Iridogorgia Verrill, 1883, Metallogorgia Versluys, 1902, Radicipes Stearns, 1883, Pseudochrysogorgia Pante & France, 2010) and predominantly (Chrysogorgia Duchassaing & Michelotti, 1864) deep-sea genera that diversified in situ. This group is sister to gold corals (Primnoidae Milne Edwards, 1857) and deep-sea bamboo corals (Keratoisidinae Gray, 1870), whose diversity also peaks in the deep sea. Nine species of Chrysogorgia that were described from depths shallower than 200 m, and mtMutS haplotypes sequenced from specimens sampled as shallow as 101 m, suggest a shallow-water emergence of some Chrysogorgia species
New record of Akashiwo sanguinea(Dinophyta) in the tropical estuarine waters of Northeastern Brazil (Western Atlantic)
The kinetic temperature of a molecular cloud at redshift 0.7: Ammonia in the gravitational lens B0218+357
Using the Effelsberg 100-m telescope, absorption in the (J,K) = (1,1), (2,2)
and (3,3) inversion lines of ammonia (NH_3) was detected at a redshift of z =
0.6847 toward the gravitational lens system B0218+357. The lambda ~ 2cm
absorption peaks at 0.5-1.0 % of the continuum level and appears to cover a
smaller fraction of the radio continuum background than lines at millimeter
wavelengths. Measured intensities are consistent with a rotation temperature of
~35K, corresponding to a kinetic temperature of ~55K. The column density toward
the core of image A then becomes N(NH_3) ~ 1 * 10^(14)cm^(-2) and fractional
abundance and gas density are of order X(NH_3)~10^(-8) and n(H_2)~5 *
10^(3)cm^(-3), respectively. Upper limits are reported for the (2,1) and (4,4)
lines of NH_3 and for transitions of the SO, DCN, OCS, SiO, C_3N, H_2CO, SiC_2,
HC_3N, HC_5N, and CH_3OH molecules. These limits and the kinetic temperature
indicate that the absorption lines are not arising from a cold dark cloud but
from a warm, diffuse, predominantly molecular medium. The physical parameters
of the absorbing molecular complex, seen at a projected distance of ~2 kpc to
the center of the lensing galaxy, are quite peculiar when compared with the
properties of clouds in the Galaxy or in nearby extragalactic systems.Comment: 7 pages, 2 figures accepted by A&
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