577 research outputs found
Far Infrared Observations of the Galactic Star Forming Regions associated with IRAS 00338+6312 and RAFGL 5111
Two Galactic star forming regions, one in a very early phase of evolution and another evolved one, associated with the IRAS sources 00338+6312 and 03595+5110 (RAFGL 5111) respectively have been studied in detail. These sources have been mapped simultaneously in two far infrared bands at 143 & 185 \micron), with about 1.5 arcmin angular resolution, using the TIFR 100 cm balloon borne telescope. The HIRES processed IRAS maps at 12, 25, 60 & 100 \micron, have been used for comparison. Whereas IRAS 00338+6312 is resolved only in the TIFR bands, RAFGL 5111 is very well resolved in both the TIFR bands, as well as in at least 3 IRAS bands. The neighbouring fainter source IRAS 04004+5114 has also been resolved in the TIFR bands. Taking advantage of the identical beams in the two TIFR bands at 143 & 185 \micron, dust colour temperature, , and optical depth, , maps have been generated for RAFGL 5111. These maps show interesting structural details. Radiative transfer modelling in spherical geometry has been carried out for individual sources. The best fit models are in good agreement with the observed spectral energy distribution (SED), radio continuum data etc. Another scheme of radiative transfer through the interstellar dust-gas cloud including the heavier elements has been used to predict ionic nebular line emission, which are in reasonable agreement with the measurements for RAFGL 5111. An important conclusion from the present study is that, for all the three sources (IRAS 00338+6312; 03595+5110; and 04004+5114, a faint source in the neighbourhood of RAFGL 5111), the best fit to the observed SED is obtained for a uniform density () cloud
Author Correction: LKB1 loss links serine metabolism to DNA methylation and tumorigenesis
Erratum for: LKB1 loss links serine metabolism to DNA methylation and tumorigenesis. [Nature. 2016
A new scheme of radiation transfer in H II regions including transient heating of grains
A new scheme of radiation transfer for understanding infrared spectra of H II
regions, has been developed. This scheme considers non-equilibrium processes
(e. g. transient heating of the very small grains, VSG; and the polycyclic
aromatic hydrocarbon, PAH) also, in addition to the equilibrium thermal
emission from normal dust grains (BG). The spherically symmetric interstellar
dust cloud is segmented into a large number of "onion skin" shells in order to
implement the non-equilibrium processes. The scheme attempts to fit the
observed SED originating from the dust component, by exploring the following
parameters : (i) geometrical details of the dust cloud, (ii) PAH size and
abundance, (iii) composition of normal grains (BG), (iv) radial distribution of
all dust (BG, VSG & PAH).
The scheme has been applied to a set of five compact H II regions (IRAS
18116- 1646, 18162-2048, 19442+2427, 22308+5812 & 18434-0242) whose spectra are
available with adequate spectral resolution. The best fit models and inferences
about the parameters for these sources are presented.Comment: 16 pages total including 3 tables and 2 figure
Water Filtration Using Plant Xylem
Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees – a readily available, inexpensive, biodegradable, and disposable material – can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings
The influence of semantic and phonological factors on syntactic decisions: An event-related brain potential study
During language production and comprehension, information about a word's syntactic properties is sometimes needed. While the decision about the grammatical gender of a word requires access to syntactic knowledge, it has also been hypothesized that semantic (i.e., biological gender) or phonological information (i.e., sound regularities) may influence this decision. Event-related potentials (ERPs) were measured while native speakers of German processed written words that were or were not semantically and/or phonologically marked for gender. Behavioral and ERP results showed that participants were faster in making a gender decision when words were semantically and/or phonologically gender marked than when this was not the case, although the phonological effects were less clear. In conclusion, our data provide evidence that even though participants performed a grammatical gender decision, this task can be influenced by semantic and phonological factors
Stabilization of Ion Concentration Polarization Using a Heterogeneous Nanoporous Junction
We demonstrate a recycled ion-flux through heterogeneous nanoporous junctions, which induce stable ion concentration polarization with an electric field. The nanoporous junctions are based on integration of ionic hydrogels whose surfaces are negatively or positively charged for cationic or anionic selectivity, respectively. Such heterogeneous junctions can be matched up in a way to achieve continuous ion-flux operation for stable concentration gradient or ionic conductance. Furthermore, the combined junctions can be used to accumulate ions on a specific region of the device.Korea Research Foundation (Grant MOEHRD: KRF-2007-331-D00040)Korean Science and Engineering Foundation (Grant MOST: R01-2007-000-20675-0)Korea Research Foundation (Grant MOEHRD: KRF-J03000)National Research Foundation of Korea (Grant NRF-2009- 352-D00034)National Institutes of Health (U.S.) (EB005743)National Science Foundation (U.S.). (CBET-0347348
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