137 research outputs found
The Chemistry of Carbonyl Cyanide. Dienophilic Properties of Carbonyl Cyanide and Diethyl Mesoxalate. Formation of Dihydropyran Derivatives
The reactions of carbonyl cyanide with butadiene or 2,3-dimethylbutadiene have been studoied. In either case there was found to take place diene condensation leading to corresponding derivatives of dihydropyran. Dihydropyran derivatives synthesis was also found to occur when die thylmesoxalate was condensed with the dienes. The correctness of the structure of the adducts obtained was established by degradation experiments
Probing Very Bright End of Galaxy Luminosity Function at z >~ 7 Using Hubble Space Telescope Pure Parallel Observations
We report the first results from the Hubble Infrared Pure Parallel Imaging
Extragalactic Survey, which utilizes the pure parallel orbits of the Hubble
Space Telescope to do deep imaging along a large number of random sightlines.
To date, our analysis includes 26 widely separated fields observed by the Wide
Field Camera 3, which amounts to 122.8 sq.arcmin in total area. We have found
three bright Y098-dropouts, which are candidate galaxies at z >~ 7.4. One of
these objects shows an indication of peculiar variability and its nature is
uncertain. The other two objects are among the brightest candidate galaxies at
these redshifts known to date L>2L*. Such very luminous objects could be the
progenitors of the high-mass Lyman break galaxis (LBGs) observed at lower
redshifts (up to z~5). While our sample is still limited in size, it is much
less subject to the uncertainty caused by "cosmic variance" than other samples
because it is derived using fields along many random sightlines. We find that
the existence of the brightest candidate at z~7.4 is not well explained by the
current luminosity function (LF) estimates at z~8. However, its inferred
surface density could be explained by the prediction from the LFs at z~7 if it
belongs to the high-redshift tail of the galaxy population at z~7.Comment: ApJL in press (accepted Dec. 27, 2010); minor corrections and one
figure added to address referee's comment
Spatio-Temporal Differences in Dystrophin Dynamics at mRNA and Protein Levels Revealed by a Novel FlipTrap Line
Dystrophin (Dmd) is a structural protein that links the extracellular matrix to actin filaments in muscle fibers and is required for the maintenance of muscles integrity. Mutations in Dmd lead to muscular dystrophies in humans and other vertebrates. Here, we report the characterization of a zebrafish gene trap line that fluorescently labels the endogenous Dmd protein (Dmd-citrine, Gt(dmd-citrine) ^(ct90a)). We show that the Dmd-citrine line recapitulates endogenous dmd transcript expression and Dmd protein localization. Using this Dmd-citrine line, we follow Dmd localization to the myosepta in real-time using time-lapse microscopy, and find that the accumulation of Dmd protein at the transverse myosepta coincides with the onset of myotome formation, a critical stage in muscle maturation. We observed that Dmd protein localizes specifically to the myosepta prior to dmd mRNA localization. Additionally, we demonstrate that the Dmd-citrine line can be used to assess muscular dystrophy following both genetic and physical disruptions of the muscle
ALMA detection of [CII] 158 micron emission from a strongly lensed z=2 star-forming galaxy
Our objectives are to determine the properties of the interstellar medium
(ISM) and of star-formation in typical star-forming galaxies at high redshift.
Following up on our previous multi-wavelength observations with HST, Spitzer,
Herschel, and the Plateau de Bure Interferometer (PdBI), we have studied a
strongly lensed z=2.013 galaxy, the arc behind the galaxy cluster MACS
J0451+0006, with ALMA to measure the [CII] 158 micron emission line, one of the
main coolants of the ISM. [CII] emission from the southern part of this galaxy
is detected at 10 . Taking into account strong gravitational lensing,
which provides a magnification of , the intrinsic lensing-corrected
[CII]158 micron luminosity is . The observed
ratio of [CII]-to-IR emission, , is found to be similar to that in nearby galaxies. The same also
holds for the observed ratio , which is
comparable to that of star-forming galaxies and active galaxy nuclei (AGN) at
low redshift. We utilize strong gravitational lensing to extend diagnostic
studies of the cold ISM to an order of magnitude lower luminosity () and SFR than previous work at high redshift.
While larger samples are needed, our results provide evidence that the cold ISM
of typical high redshift galaxies has physical characteristics similar to
normal star forming galaxies in the local Universe.Comment: 5 pages, 4 figures. Accepted for publication in Astronomy &
Astrophysics, Letter
Photometry in UV astronomical images of extended sources in crowded field using deblended images in optical visible bands as Bayesian priors
Photometry of astrophysical sources, galaxies and stars, in crowded field images, if an old problem, is still a challenging goal, as new space survey missions are launched, releasing new data with increased sensibility, resolution and field of view. The GALEX mission, observes in two UV bands and produces deep sky images of millions of galaxies or stars mixed together. These UV observations are of lower resolution than same field observed in visible bands, and with a very faint signal, at the level of the photon noise for a substantial fraction of objects. Our purpose is to use the better known optical counterparts as prior information in a Bayesian approach to deduce the UV flux. Photometry of extended sources has been addressed several times using various techniques: background determination via sigma clipping, adaptative-aperture, point-spread-function photometry, isophotal photometry, to lists some. The Bayesian approach of using optical priors for solving the UV photometry has already been applied by our team in a previous work. Here we describe the improvement of using the extended shape inferred by deblending the high resolution optical images and not only the position of the optical sources. The resulting photometric accuracy has been tested with simulation of crowded UV fields added on top of real UV images. Finally, this helps to converge to smaller and flat residual and increase the faint source detection threshold. It thus gives the opportunity to work on 2nd order effects, like improving the knowledge of the background or point-spread function by iterating on them
Wady zastawkowe serca i różne profile dobowe ciśnienia tętniczego
Introduction. Valvular heart diseases (VHD) increase the risk of cardiovascular morbidity and mortality. Little is known about the correlation between circadian blood pressure profile (CBPP) and VHD. The study aimed to clarify the association between CBPP and VHD prevalence.
Material and methods. 103 consecutive patients (male: 50.5%), who underwent 24-hour ambulatory blood pressure measurement (ABPM) and Holter electrocardiography simultaneously were analysed. Patients were divided into 3 groups: dipping was defined as 10–20% (28.2%), non-dipping as < 10% (50.5%) fall in nocturnal blood pressure (BP) and reverse-dipping as higher nocturnal than diurnal BP (21.4%). VHD was assessed by transthoracic echocardiography and described as mild, moderate or severe regurgitation or stenosis accordingly. Further, the severity of VHD, nocturnal fall pattern and ABPM features in all groups were compared.
Results. The authors found no statistically significant association between severity of VHD and dipping status. The presented study showed some correlations between VHD severity and different ABPM parameters.
Conclusions. Though severity of VHD did not influence dipping status obtained by ABPM, there were associations between VHD and ABPM outcomes. Further studies are needed.Wstęp. Wady zastawkowe serca (VHD) zwiększają ryzyko zachorowań i zgonów z przyczyn sercowo-naczyniowych. Niewiele wiadomo na temat zależności między profilem dobowym ciśnienia tętniczego (CBPP) a VHD. Celem tej pracy było wyjaśnienie związku między CBPP a VHD.
Materiał i meody. Do badania włączono 103 kolejnych pacjentów (mężczyźni 50,5%), u których równocześnie wykonano całodobowy pomiar ciśnienia tętniczego (ABPM) i 24-godzinny zapis elektrokardiograficzny metodą Holtera. Podzielono ich na trzy grupy: dippers — zdefiniowanych jako osoby z ciśnieniem tętniczym (BP) w nocy o 10–20% niższym niż w ciągu dnia (28,2%), non-dippers — osoby ze spadkiem BP w nocy mniejszym niż 10% (50,5%), reverse-dippers — osoby z wyższymi wartościami BP w nocy niż w ciągu dnia (21,4%). Metodą echokardiografii przezklatkowej oceniano VHD jako małą, umiarkowaną lub ciężką. Następnie porównywano ciężkość VHD, CBPP i dane z ABPM we wszystkich grupach.
Wyniki. Nie znaleziono istotnej statystycznie zależności między cięż kością VHD a CBPP. Zaobserwowano korelację między ciężkością VHD a niektórymi parametrami ocenianymi w trakcie ABPM.
Wnioski. Choć ciężkość VHD nie wpływała na CBPP, to istnieją zależności między wynikami VHD i ABPM. Konieczne są
dalsze badania
The VLA-COSMOS Survey. IV. Deep Data and Joint Catalog
In the context of the VLA-COSMOS Deep project additional VLA A array
observations at 1.4 GHz were obtained for the central degree of the COSMOS
field and combined with the existing data from the VLA-COSMOS Large project. A
newly constructed Deep mosaic with a resolution of 2.5" was used to search for
sources down to 4 sigma with 1 sigma ~ 12 microJy/beam in the central 50'x50'.
This new catalog is combined with the catalog from the Large project (obtained
at 1.5"x1.4" resolution) to construct a new Joint catalog. All sources listed
in the new Joint catalog have peak flux densities of >5 sigma at 1.5" and/or
2.5" resolution to account for the fact that a significant fraction of sources
at these low flux levels are expected to be slighty resolved at 1.5"
resolution. All properties listed in the Joint catalog such as peak flux
density, integrated flux density and source size are determined in the 2.5"
resolution Deep image. In addition, the Joint catalog contains 43 newly
identified multi-component sources.Comment: 34 pages, 20 figures (3 at reduced resolution). Accepted for
publication in ApJS
Photometry in UV astronomical images of extended sources in crowded field using deblended images in optical visible bands as Bayesian priors
Photometry of astrophysical sources, galaxies and stars, in crowded field images, if an old problem, is still a challenging goal, as new space survey missions are launched, releasing new data with increased sensibility, resolution and field of view. The GALEX mission, observes in two UV bands and produces deep sky images of millions of galaxies or stars mixed together. These UV observations are of lower resolution than same field observed in visible bands, and with a very faint signal, at the level of the photon noise for a substantial fraction of objects. Our purpose is to use the better known optical counterparts as prior information in a Bayesian approach to deduce the UV flux. Photometry of extended sources has been addressed several times using various techniques: background determination via sigma clipping, adaptative-aperture, point-spread-function photometry, isophotal photometry, to lists some. The Bayesian approach of using optical priors for solving the UV photometry has already been applied by our team in a previous work. Here we describe the improvement of using the extended shape inferred by deblending the high resolution optical images and not only the position of the optical sources. The resulting photometric accuracy has been tested with simulation of crowded UV fields added on top of real UV images. Finally, this helps to converge to smaller and flat residual and increase the faint source detection threshold. It thus gives the opportunity to work on 2nd order effects, like improving the knowledge of the background or point-spread function by iterating on them
Detections of CO Molecular Gas in 24um-Bright ULIRGs at z~2 in the Spitzer First Look Survey
We present CO observations of 9 ULIRGs at z~2 with S(24\mu m)>1mJy,
previously confirmed with the mid-IR spectra in the Spitzer First Look Survey.
All targets are required to have accurate redshifts from Keck/GEMINI near-IR
spectra. Using the Plateau de Bure millimeter-wave Interferometer (PdBI) at
IRAM, we detect CO J(3-2) [7 objects] or J(2-1) [1 object] line emission from 8
sources with integrated intensities Ic ~(5-9)sigma. The CO detected sources
have a variety of mid-IR spectra, including strong PAH, deep silicate
absorption and power-law continuum, implying that these molecular gas rich
objects at z~2 could be either starbursts or dust obscured AGNs. The measured
line luminosity L'[CO] is (1.28-3.77)e+10[K km/s pc^2]. The averaged molecular
gas mass M(H2) is 1.7e+10Msun, assuming CO-to-H2 conversion factor of
0.8Msun/[K km/s pc^2]. Three sources (33%) -- MIPS506, MIPS16144 & MIPS8342 --
have double peak velocity profiles. The CO double peaks in MIPS506 and
MIPS16144 show spatial separations of 45kpc and 10.9kpc, allowing the estimates
of the dynamical masses of 3.2e+11*sin^(-2)(i)Msun and 5.4e+11*sin^{-2}(i)Msun
respectively. The implied gas fraction, M(gas)/M(dyn), is 3% and 4%, assuming
an average inclination angle. Finally, the analysis of the HST/NIC2 images,
mid-IR spectra and IR SED revealed that most of our sources are mergers,
containing dust obscured AGNs dominating the luminosities at (3-6)um. Together,
these results provide some evidence suggesting SMGs, bright 24um z~2 ULIRGs and
QSOs could represent three different stages of a single evolutionary sequence,
however, a complete physical model would require much more data, especially
high spatial resolution spectroscopy.Comment: 15 pages, 8 figures, accepted for publication in ApJ
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