1,175 research outputs found
PPM-Extended (PPMX) - a catalogue of positions and proper motions
Aims: We build a catalogue PPM-Extended (PPMX) on the ICRS system which is
complete down to a well-defined limiting magnitude and contains the best
presently available proper motions to be suited for kinematical studies in the
Galaxy.
Methods: We perform a rigorous weighted least-squares adjustment of
individual observations, spread over more than a century, to determine mean
positions and proper motions. The stellar content of PPMX is taken from GSC 1.2
supplemented by catalogues like ARIHIP, PPM and Tycho-2 at the bright end. All
observations have been weighted according to their individual accuracy. The
catalogue has been screened towards rejecting false entries in the various
source catalogues.
Results: PPM-Extended (PPMX) is a catalogue of 18,088,920 stars containing
astrometric and photometric information. Its limiting magnitude is about 15.2
in the GSC photometric system. PPMX consists of three parts: a) a survey
complete down to R_U = 12.8 in the magnitude system of UCAC2; b) additional
stars of high-precision proper motions, and c) all other stars from GSC 1.2
identified in 2MASS. The typical accuracy of the proper motions is 2mas/y for
66 percent of the survey stars (a) and the high-precision stars (b), and about
10 mas/y for all other stars. PPMX contains photometric information from
ASCC-2.5 and 2MASS.Comment: 9 pages, 8 figures, accepted for publication in Astronomy and
Astrophysic
Optical control of coherent interactions between quantum dot electron spins
Coherent interactions between spins in quantum dots are a key requirement for
quantum gates. We have performed pump-probe experiments in which pulsed lasers
emitting at different photon energies manipulate two distinct subsets of
electron spins within an inhomogeneous InGaAs quantum dot ensemble. The spin
dynamics are monitored through their precession about an external magnetic
field. These measurements demonstrate spin precession phase shifts and
modulations of the magnitude of one subset of oriented spins after optical
orientation of the second subset. The observations are consistent with results
from a model using a Heisenberg-like interaction with microeV-strength.Comment: 5 pages, 4 figure
Diversity and Distribution of Borrelia hermsii
Multilocus sequence analysis and laboratory experiments suggest that birds may play a role in maintaining and dispersing this pathogen
Effect of pump-probe detuning on the Faraday rotation and ellipticity signals of mode-locked spins in InGaAs quantum dots
We have studied the Faraday rotation and ellipticity signals in ensembles of
singly-charged (In,Ga)As/GaAs quantum dots by pump-probe spectroscopy. For
degenerate pump and probe we observe that the Faraday rotation signal amplitude
first grows with increasing the time separation between pump and probe before a
decay is observed for large temporal separations. The temporal behavior of the
ellipticity signal, on the other hand, is regular: its amplitude decays with
the separation. By contrast, for detuned pump and probe the Faraday rotation
and ellipticty signals both exhibit similar and conventional behavior. The
experimental results are well described in the frame of a recently developed
microscopic theory [Phys. Rev. B 80, 104436 (2009)]. The comparison between
calculations and experimental data allows us to provide insight into the
spectral dependence of the electron spin precession frequencies and extract the
electron g-factor dependence on energy.Comment: 9 pages, 7 figure
Sterilization of lung matrices by supercritical carbon dioxide
Lung engineering is a potential alternative to transplantation for patients with end-stage pulmonary failure. Two challenges critical to the successful development of an engineered lung developed from a decellularized scaffold include (i) the suppression of resident infectious bioburden in the lung matrix, and (ii) the ability to sterilize decellularized tissues while preserving the essential biological and mechanical features intact. To date, the majority of lungs are sterilized using high concentrations of peracetic acid (PAA) resulting in extracellular matrix (ECM) depletion. These mechanically altered tissues have little to no storage potential. In this study, we report a sterilizing technique using supercritical carbon dioxide (ScCO(2)) that can achieve a sterility assurance level 10(−6) in decellularized lung matrix. The effects of ScCO(2) treatment on the histological, mechanical, and biochemical properties of the sterile decellularized lung were evaluated and compared with those of freshly decellularized lung matrix and with PAA-treated acellular lung. Exposure of the decellularized tissue to ScCO(2) did not significantly alter tissue architecture, ECM content or organization (glycosaminoglycans, elastin, collagen, and laminin), observations of cell engraftment, or mechanical integrity of the tissue. Furthermore, these attributes of lung matrix did not change after 6 months in sterile buffer following sterilization with ScCO(2), indicating that ScCO(2) produces a matrix that is stable during storage. The current study's results indicate that ScCO(2) can be used to sterilize acellular lung tissue while simultaneously preserving key biological components required for the function of the scaffold for regenerative medicine purposes
Tick-borne Relapsing Fever Caused by Borrelia hermsii, Montana
Five persons contracted tick-borne relapsing fever after staying in a cabin in western Montana. Borrelia hermsii was isolated from the blood of two patients, and Ornithodoros hermsi ticks were collected from the cabin, the first demonstration of this bacterium and tick in Montana. Relapsing fever should be considered when patients who reside or have vacationed in western Montana exhibit a recurring febrile illness
Characterization of different fruit wines made from cacao, cupuassu, gabiroba, jaboticaba and umbu
The main aim of this work was to produce fruit wines from pulp of gabiroba, cacao, umbu, cupuassu and jaboticaba and characterize them using gas chromatography–mass spectrometry for determination of minor compounds and gas chromatography-flame ionization detection for major compounds. Ninety-nine compounds (C6 compounds, alcohols, monoterpenic alcohols, monoterpenic oxides, ethyl esters, acetates, volatile phenols, acids, carbonyl compounds, sulfur compounds and sugars) were identified in fruit wines. The typical composition for each fruit wine was evidenced by principal component analysis and Tukey test. The yeast UFLA CA 1162 was efficient in the fermentation of the fruit pulp used in this work. The identification and quantification of the compounds allowed a good characterization of the fruit wines. With our results, we conclude that the use of tropical fruits in the production of fruit wines is a viable alternative that allows the use of harvest surpluses and other underused fruits, resulting in the introduction of new products into the market.Conselho Nacional de Desenvolvimento
Científico e Tecnológico do Brasil (CNPq) and CAPES (Coordenação
de Aperfeiçoamento de Pessoal de Nível Superior
- …