519 research outputs found
IUE observations of Seyfert galaxies
The L alpha/H beta ratio and line profiles for several galaxies are presented. The continuous energy distribution of NGC 4151 and MKN 509 are presented from the X-ray region to the infrared
Asymptotic entanglement in 1D quantum walks with a time-dependent coined
Discrete-time quantum walk evolve by a unitary operator which involves two
operators a conditional shift in position space and a coin operator. This
operator entangles the coin and position degrees of freedom of the walker. In
this paper, we investigate the asymptotic behavior of the coin position
entanglement (CPE) for an inhomogeneous quantum walk which determined by two
orthogonal matrices in one-dimensional lattice. Free parameters of coin
operator together provide many conditions under which a measurement perform on
the coin state yield the value of entanglement on the resulting position
quantum state. We study the problem analytically for all values that two free
parameters of coin operator can take and the conditions under which
entanglement becomes maximal are sought.Comment: 23 pages, 4 figures, accepted for publication in IJMPB. arXiv admin
note: text overlap with arXiv:1001.5326 by other author
COBE Observations of the Microwave Counterparts of Gamma Ray Bursts
We have used the data from the COBE satellite to search for delayed microwave
emission (31 - 90 GHz) from Gamma Ray Bursts (GRBs). The large beam
of COBE is well matched to the large positional uncertainties in the GRB
locations, although it also means that fluxes from (point source) GRB objects
will be diluted. In view of this we are doing a statistical search of the GRBs
which occurred during the currently released COBE DMR data (years 1990 and
1991), which overlap GRBs recorded by GRO. Here we concentrate on
just the top 10 GRBs (in peak counts/second). We obtain the limits on the
emission by comparing the COBE fluxes before and after the GRB at the GRB
location. Since it is thought that the microwave emission should lag the GRB
event, we have searched the GRB position for emission in the few months
following the GRB occurrence.Comment: 5 pages, LaTE
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Contractile deficits in engineered cardiac microtissues as a result of MYBPC3 deficiency and mechanical overload.
The integration of in vitro cardiac tissue models, human induced pluripotent stem cells (hiPSCs) and genome-editing tools allows for the enhanced interrogation of physiological phenotypes and recapitulation of disease pathologies. Here, using a cardiac tissue model consisting of filamentous three-dimensional matrices populated with cardiomyocytes derived from healthy wild-type (WT) hiPSCs (WT hiPSC-CMs) or isogenic hiPSCs deficient in the sarcomere protein cardiac myosin-binding protein C (MYBPC3-/- hiPSC-CMs), we show that the WT microtissues adapted to the mechanical environment with increased contraction force commensurate to matrix stiffness, whereas the MYBPC3-/- microtissues exhibited impaired force development kinetics regardless of matrix stiffness and deficient contraction force only when grown on matrices with high fibre stiffness. Under mechanical overload, the MYBPC3-/- microtissues had a higher degree of calcium transient abnormalities, and exhibited an accelerated decay of calcium dynamics as well as calcium desensitization, which accelerated when contracting against stiffer fibres. Our findings suggest that MYBPC3 deficiency and the presence of environmental stresses synergistically lead to contractile deficits in cardiac tissues
Infrared receivers for low background astronomy: Incoherent detectors and coherent devices from one micrometer to one millimeter
The status of incoherent detectors and coherent receivers over the infrared wavelength range from one micrometer to one millimeter is described. General principles of infrared receivers are included, and photon detectors, bolometers, coherent receivers, and important supporting technologies are discussed, with emphasis on their suitability for low background astronomical applications. Broad recommendations are presented and specific opportunities are identified for development of improved devices
Tameness of holomorphic closure dimension in a semialgebraic set
Given a semianalytic set S in a complex space and a point p in S, there is a
unique smallest complex-analytic germ at p which contains the germ of S, called
the holomorphic closure of S at p. We show that if S is semialgebraic then its
holomorphic closure is a Nash germ, for every p, and S admits a semialgebraic
filtration by the holomorphic closure dimension. As a consequence, every
semialgebraic subset of a complex vector space admits a semialgebraic
stratification into CR manifolds satisfying a strong version of the condition
of the frontier.Comment: Published versio
miRNAs as common regulators of the transforming growth factor (TGF)-β pathway in the preeclamptic placenta and cadmium-treated trophoblasts: Links between the environment, the epigenome and preeclampsia
Preeclampsia (PE) is a pregnancy disorder characterized by high blood pressure and proteinuria that can cause adverse health effects in both mother and fetus. There is no current cure for PE other than delivery of the fetus. While the etiology is unknown, poor placentation of the placenta due to aberrant signaling of growth and angiogenic factors has been postulated as causal factors of PE. In addition, environmental contaminants, such as the metal cadmium (Cd), have been linked to placental toxicity and increased risk of developing PE. Here, we use a translational study design to investigate genomic and epigenomic alterations in both placentas and placental trophoblasts, focused on the angiogenesis-associated transforming growth factor-beta (TGF-β) pathway. Genes within the TGF-β pathway displayed increased expression in both the preeclamptic placenta and Cd-treated trophoblasts. In addition, miRNAs that target the TGF-β pathway were also significantly altered within the preeclamptic placenta and Cd-treated trophoblasts. Integrative analysis resulted in the identification of a subset of Cd-responsive miRNAs, including miR-26a and miR-155, common to preeclamptic placentas and Cd-treated trophoblasts. These miRNAs have previously been linked to PE and are predicted to regulate members of the TGF-β pathway. Results from this study provide future targets for PE treatment
miRNAs as common regulators of the transforming growth factor (TGF)-β pathway in the preeclamptic placenta and cadmium-treated trophoblasts: Links between the environment, the epigenome and preeclampsia
Preeclampsia (PE) is a pregnancy disorder characterized by high blood pressure and proteinuria that can cause adverse health effects in both mother and fetus. There is no current cure for PE other than delivery of the fetus. While the etiology is unknown, poor placentation of the placenta due to aberrant signaling of growth and angiogenic factors has been postulated as causal factors of PE. In addition, environmental contaminants, such as the metal cadmium (Cd), have been linked to placental toxicity and increased risk of developing PE. Here, we use a translational study design to investigate genomic and epigenomic alterations in both placentas and placental trophoblasts, focused on the angiogenesis-associated transforming growth factor-beta (TGF-β) pathway. Genes within the TGF-β pathway displayed increased expression in both the preeclamptic placenta and Cd-treated trophoblasts. In addition, miRNAs that target the TGF-β pathway were also significantly altered within the preeclamptic placenta and Cd-treated trophoblasts. Integrative analysis resulted in the identification of a subset of Cd-responsive miRNAs, including miR-26a and miR-155, common to preeclamptic placentas and Cd-treated trophoblasts. These miRNAs have previously been linked to PE and are predicted to regulate members of the TGF-β pathway. Results from this study provide future targets for PE treatment
FUSE and HST STIS Observations of Hot and Cold Gas in the AB Aurigae System
We present the first observations of a Herbig Ae star with a circumstellar
disk by the Far Ultraviolet Spectroscopic Explorer (FUSE), as well as a
simultaneous observation of the star obtained with the Hubble Space Telescope
Space Telescope Imaging Spectrograph (STIS). The spectra of AB Aurigae show
emission and absorption features arising from gasses that have a wide range in
temperature, from hot OVI emission to cold molecular hydrogen and CO
absorption. Emissions from the highly ionized species OVI and CIII present in
the FUSE spectrum are redshifted, while absorption features arising from
low-ionization species like OI, NI, and SiII are blueshifted and show
characteristic stellar wind line-profiles. We find the total column density of
molecular hydrogen toward AB Aur from the FUSE apectrum, N(H_2) = (6.8 +/- 0.5)
x 10^19 cm^-2. The gas kinetic temperature of the molecular hydrogen derived
from the ratio N(J=1)/N(J=0) is 65 +/- 4 K. The column density of the CO
observed in the STIS spectrum is N(CO) = (7.1 +/- 0.5) x 10^13 cm^-2, giving a
CO/H_2 ratio of (1.04 +/- 0.11) x 10^-6. We also use the STIS spectrum to find
the column density of HI, permitting us to calculate the total column density
of hydrogen atoms, the fractional abundance of H_2, and the gas-to-dust ratio.Comment: 5 pages, including 6 figures. LaTex2e (emulateapj5.sty). Accepted for
publication in ApJ Letter
UV-optical from space
The following subject areas are covered: (1) the science program (star formation and origins of planetary systems; structure and evolution of the interstellar medium; stellar population; the galactic and extragalactic distance scale; nature of galaxy nuclei, AGNs, and QSOs; formation and evolution of galaxies at high redshifts; and cosmology); (2) implementation of the science program; (3) the observatory-class missions (HST; LST - the 6m successor to HST; and next-generation 16m telescope); (4) moderate and small missions (Delta-class Explorers; imaging astrometric interferometer; small Explorers; optics development and demonstrations; and supporting ground-based capabilities); (5) prerequisites - the current science program (Lyman-FUSE; HTS optimization; the near-term science program; data analysis, modeling, and theory funding; and archives); (6) technologies for the next century; and (7) lunar-based telescopes and instruments
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