4,422 research outputs found
Prime Focus Spectrograph - Subaru's future -
The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and
Redshifts (SuMIRe) project has been endorsed by Japanese community as one of
the main future instruments of the Subaru 8.2-meter telescope at Mauna Kea,
Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology
with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution.
Taking advantage of Subaru's wide field of view, which is further extended with
the recently completed Wide Field Corrector, PFS will enable us to carry out
multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A
microlens is attached at each fiber entrance for F-ratio transformation into a
larger one so that difficulties of spectrograph design are eased. Fibers are
accurately placed onto target positions by positioners, each of which consists
of two stages of piezo-electric rotary motors, through iterations by using
back-illuminated fiber position measurements with a wide-field metrology
camera. Fibers then carry light to a set of four identical fast-Schmidt
spectrographs with three color arms each: the wavelength ranges from 0.38
{\mu}m to 1.3 {\mu}m will be simultaneously observed with an average resolving
power of 3000. Before and during the era of extremely large telescopes, PFS
will provide the unique capability of obtaining spectra of 2400
cosmological/astrophysical targets simultaneously with an 8-10 meter class
telescope. The PFS collaboration, led by IPMU, consists of USP/LNA in Brazil,
Caltech/JPL, Princeton, & JHU in USA, LAM in France, ASIAA in Taiwan, and
NAOJ/Subaru.Comment: 13 pages, 11 figures, submitted to "Ground-based and Airborne
Instrumentation for Astronomy IV, Ian S. McLean, Suzanne K. Ramsay, Hideki
Takami, Editors, Proc. SPIE 8446 (2012)
Optimizing the fast Rydberg quantum gate
The fast phase gate scheme, in which the qubits are atoms confined in sites
of an optical lattice, and gate operations are mediated by excitation of
Rydberg states, was proposed by Jaksch et al. Phys. Rev. Lett. 85, 2208 (2000).
A potential source of decoherence in this system derives from motional heating,
which occurs if the ground and Rydberg states of the atom move in different
optical lattice potentials. We propose to minimize this effect by choosing the
lattice photon frequency \omega so that the ground and Rydberg states have the
same frequency-dependent polarizability \alpha(omega). The results are
presented for the case of Rb.Comment: 5 pages, submitted to PR
On the Evolution of Dust Mineralogy, From Protoplanetary Disks to Planetary Systems
Mineralogical studies of silicate features emitted by dust grains in
protoplanetary disks and Solar System bodies can shed light on the progress of
planet formation. The significant fraction of crystalline material in comets,
chondritic meteorites and interplanetary dust particles indicates a
modification of the almost completely amorphous ISM dust from which they
formed. The production of crystalline silicates thus must happen in
protoplanetary disks, where dust evolves to build planets and planetesimals.
Different scenarios have been proposed, but it is still unclear how and when
this happens. This paper presents dust grain mineralogy of a complete sample of
protoplanetary disks in the young Serpens cluster. These results are compared
to those in the young Taurus region and to sources that have retained their
protoplanetary disks in the older Upper Scorpius and Eta Chamaeleontis stellar
clusters, using the same analysis technique for all samples. This comparison
allows an investigation of the grain mineralogy evolution with time for a total
sample of 139 disks. The mean cluster age and disk fraction are used as
indicators of the evolutionary stage of the different populations. Our results
show that the disks in the different regions have similar distributions of mean
grain sizes and crystallinity fractions (~10-20%) despite the spread in mean
ages. Furthermore, there is no evidence of preferential grain sizes for any
given disk geometry, nor for the mean cluster crystallinity fraction to
increase with mean age in the 1-8 Myr range. The main implication is that a
modest level of crystallinity is established in the disk surface early on (< 1
Myr), reaching a equilibrium that is independent of what may be happening in
the disk midplane. These results are discussed in the context of planet
formation, in comparison with mineralogical results from small bodies in our
Solar System. [Abridged]Comment: Accepted for publication in the Astrophysical Journa
Abundance and Species Richness of Leafhoppers and Planthoppers (Hemiptera: Cicadellidae and Delphacidae) in Brazilian Maize Crops
Fil: De Oliveira, Charles Martins. Embrapa Cerrados. Planaltina. BrasÃlia/DF; BrazilFil: De Oliveira, Elizabeth. Embrapa Milho e Sorgo. Sete Lagoas/MG; BrazilFil: Prazeres De Souza, Isabel Regina. Embrapa Milho e Sorgo. Sete Lagoas/MG; BrazilFil: Alves, Elcio. DuPont do Brazil S.A. DivisÆo Pioneer Sementes. Itumbiara/GO; BrazilFil: Dolezal, William. Pioneer Hi-Bred International. Itumbiara/GO; BrazilFil: Paradell, Susana Liria. División EntomologÃa. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Marino de Remes Lenicov, Ana MarÃa. División EntomologÃa. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Frizzas, Marina Regina. Universidade de BrasÃlia. Departamento de Zoologia. Instituto de Ciências Biológicas. BrasÃlia/DF; Brazi
J-PLUS: A wide-field multi-band study of the M15 globular cluster. Evidence of multiple stellar populations in the RGB
The Javalambre Photometric Local Universe Survey (J-PLUS) provides wide
field-of-view images in 12 narrow, intermediate and broad-band filters
optimized for stellar photometry. Here we have applied J-PLUS data for the
first time for the study of Galactic GCs using science verification data
obtained for the very metal-poor GC M\,15. Our J-PLUS data provide
low-resolution spectral energy distributions covering the near-UV to the
near-IR, allowing us to search for MPs based on pseudo-spectral fitting
diagnostics. J-PLUS CMDs are found to be particularly useful to search for
splits in the sequences formed by the upper red giant branch (RGB) and
asymptotic giant branch (AGB) stars. We interpret these split sequences as
evidence for the presence of MPs. This demonstrates that the J-PLUS survey will
have sufficient spatial coverage and spectral resolution to perform a large
statistical study of GCs through multi-band photometry in the coming years.Comment: 11 pages, 11 figures. Accepted for publication @ A&
Spectroscopic Time-series Performance of JWST/NIRSpec from Commissioning Observations
We report on JWST commissioning observations of the transiting exoplanet
HAT-P-14 b, obtained using the Bright Object Time Series (BOTS) mode of the
NIRSpec instrument with the G395H/F290LP grating/filter combination
(m). While the data were used primarily to verify that the NIRSpec BOTS
mode is working as expected, and to enable it for general scientific use, they
yield a precise transmission spectrum which we find is featureless down to the
precision level of the instrument, consistent with expectations given
HAT-P-14~b's small scale-height and hence expected atmospheric features. The
exquisite quality and stability of the \emph{JWST/NIRSpec} transit spectrum --
almost devoid of any systematic effects -- allowed us to obtain median
uncertainties of 50-60 ppm in this wavelength range at a resolution of
in a single exposure, which is in excellent agreement with pre-flight
expectations and close to the (or at the) photon-noise limit for a ,
F-type star like HAT-P-14. These observations showcase the ability of
NIRSpec/BOTS to perform cutting-edge transiting exoplanet atmospheric science,
setting the stage for observations and discoveries to be made in Cycle 1 and
beyond.Comment: 16 pages, 14 figures; part of the PASP Focus Issue "JWST Time-Series
Observations: Commissioning Performance". Paper after the first round of
referee comments; inputs welcom
Measurement of the lifetime
Using a data set corresponding to an integrated luminosity of ,
collected by the LHCb experiment in collisions at centre-of-mass energies
of 7 and 8 TeV, the effective lifetime in the
decay mode, , is measured to be ps. Assuming
conservation, corresponds to the lifetime of the light
mass eigenstate. This is the first measurement of the effective
lifetime in this decay mode.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-017.htm
Enhanced Leishmania braziliensis Infection Following Pre-Exposure to Sandfly Saliva
Parasites of the genus Leishmania cause a variety of diseases known as leishmaniasis, that are transmitted by bites of female sand flies that, during blood-feeding, inject humans with parasites and saliva. It was shown that, in mice, immunity to sand-fly saliva is able to protect against the development of leishmaniasis. We have investigated, in the present study, whether this finding extends the sand fly species Lutzomyia intermedia, which is responsible for transmission of Leishmania braziliensis, a parasite species able to cause destructive skin lesions that can be fatal if left untreated. We observed that mice injected with sand fly saliva develop a specific immune response against salivary proteins. Most importantly, however, this immune response was unable to protect mice against a challenge infection with L. braziliensis, indicating that exposure to this sand fly saliva is harmful to the host. Indeed, subjects with cutaneous leishmaniasis have a higher immune response against L. intermedia saliva. These findings indicate that the anti-saliva immune response to sand fly saliva plays an important role in the outcome of leishmaniasis caused by L. braziliensis, in both mice and humans, and emphasize possible hurdles in the development of vaccines based on sand fly saliva
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