736 research outputs found
Characterizing Atacama B-mode Search Detectors with a Half-Wave Plate
The Atacama B-Mode Search (ABS) instrument is a cryogenic (10 K)
crossed-Dragone telescope located at an elevation of 5190 m in the Atacama
Desert in Chile that observed for three seasons between February 2012 and
October 2014. ABS observed the Cosmic Microwave Background (CMB) at large
angular scales () to limit the B-mode polarization spectrum around
the primordial B-mode peak from inflationary gravity waves at .
The ABS focal plane consists of 480 transition-edge sensor (TES) bolometers.
They are coupled to orthogonal polarizations from a planar ortho-mode
transducer (OMT) and observe at 145 GHz. ABS employs an ambient-temperature,
rapidly rotating half-wave plate (HWP) to mitigate systematic effects and move
the signal band away from atmospheric noise, allowing for the recovery of
large angular scales. We discuss how the signal at the second harmonic of the
HWP rotation frequency can be used for data selection and for monitoring the
detector responsivities.Comment: 7 pages, 3 figures, conference proceedings submitted to the Journal
of Low Temperature Detector
Amifostine (wr-2721), A Cytoprotective Agent During High-dose Cyclophosphamide Treatment Of Non-hodgkin's Lymphomas: A Phase Ii Study.
Clinical trials indicate that amifostine may confer protection on various normal tissues without attenuating anti-tumor response. When administered prior to chemotherapy or radiotherapy, it may provide a broad spectrum of cytoprotection including against alkylating drugs. The mechanism of protection resides in the metabolism at normal tissue site by membrane-bound alkaline phosphatase. Toxicity of this drug is moderate with hypotension, nausea and vomiting, and hypocalcemia being observed. We report a phase II study using amifostine as a protective drug against high-dose cyclophosphamide (HDCY) (7 g/m2), used to mobilize peripheral blood progenitor cells (PBPC) and to reduce tumor burden. We enrolled 29 patients, 22 (75. 9%) affected by aggressive and 7 (24.1%) by indolent non-Hodgkin's lymphoma (NHL), who were submitted to 58 infusions of amifostine and compared them with a historical group (33 patients) affected by aggressive NHL and treated with VACOP-B followed by HDCY. The most important results in favor of amifostine were the reduction of intensity of cardiac, pulmonary and hepatic toxicity, and a significant reduction of frequency and severity of mucositis (P = 0. 04). None of the 29 patients died in the protected group, while in the historical group 2/33 patients died because of cardiac or pulmonary toxicity and 2 patients stopped therapy due to toxicity. Amifostine did not prevent the aplastic phase following HDCY. PBPC collection and hematological recovery were adequate in both groups. The number of CFU-GM (colony-forming units-granulocyte/macrophage) colonies and mononuclear cells in the apheresis products was significantly higher in the amifostine group (P = 0.02 and 0.01, respectively). Side effects were mild and easily controlled. We conclude that amifostine protection should be useful in HDCY to protect normal tissues, with acceptable side effects.33791-
Les risques sanitaires lies a l\u2019utilisation des pesticides dans les bas-fonds rizicoles de la commune de dano, Province du Ioba Burkina Faso
Pesticides are an essential component of agricultural production
techniques for pests and weeds control. In Burkina Faso, failure to
observe good practices for pesticides use exposes farmers to health
risks. The study presents health risks related to pesticide management
in rice fields in Dano through a survey of 158 rice farmers working in
inland valleys. Socio-demographic characteristics of farmers, the types
of pesticides used and their effects on health were documented. Rice
farming in Dano is mainly done by an ageing population with an average
of over 50 years (60%). In addition, farmers\u2019 education level is
low, with an illiteracy rate of 61 and only 32% of farmers attaining
primary school education. Risky behaviours of pesticides use are
common, especially inadequate of farmer protection, poor practices of
storage and re-use of pesticide products. Twelve types of pesticides
were identified, of which 40% are not officially registered. The main
active components in herbicides are Glyphosate, Paraquat, Bensulfuron
methyl and Bispyribac-sodium. Health risks of pesticide use reported by
farmers included various poisoning symptoms. To mitigate pesticide
poisoning prevalence associated with poor farming practices, awareness
campaigns should be conducted to inform farmers to use pesticides
safely.Les produits pesticides constituent de nos jours une composante
essentielle des techniques de production agricole pour le contr\uf4le
des ravageurs et des mauvaises herbes. Au Burkina Faso, le non respect
des bonnes pratiques d\u2019utilisation des pesticides pose un
v\ue9ritable probl\ue8me de sant\ue9 des populations.
L\u2019\ue9tude pr\ue9sente les risques sanitaires de gestion des
pesticides agricoles. Une enqu\ueate de terrain a \ue9t\ue9
r\ue9alis\ue9e dans la Commune de Dano aupr\ue8s de 158
producteurs rizicoles. Le questionnaire a port\ue9 sur les
caract\ue9ristiques sociod\ue9mographiques des producteurs
rizicoles, les types de pesticides utilis\ue9s et leurs effets sur la
sant\ue9. L\u2019\ue9tude montre que la riziculture \ue0 Dano
est une activit\ue9 principalement exerc\ue9e par une population
vieillissante dont les plus de 50 ans repr\ue9sentent pr\ue8s de
60%. De plus, la population est analphab\ue8te \ue0 61% contre 32%
des producteurs ayant fr\ue9quent\ue9 l\u2019\ue9cole primaire.
Les mauvaises pratiques d\u2019utilisation des pesticides sont
fr\ue9quentes et concernent surtout l\u2019insuffisance des
\ue9quipements de protection individuels des producteurs, les
pratiques de stockage et de r\ue9utilisation des reliquats de
pesticides. Douze types de pesticides ont \ue9t\ue9 identifi\ue9s
dont 40% ne sont pas homologu\ue9s. Les principales mati\ue8res
actives dans les herbicides sont le Glyphosate, le Paraquat, le
Bensulfuron methyl et le Bispyribac-sodium. Les effets sanitaires de
l\u2019utilisation des pesticides sont ressentis par les producteurs
agricoles \ue0 travers divers sympt\uf4mes des intoxications. Pour
r\ue9duire la pr\ue9valence des intoxications aux pesticides, des
campagnes d\u2019information et de sensibilisation doivent \ueatre
men\ue9es \ue0 l\u2019endroit des populations et des producteurs
pour une utilisation s\ue9curis\ue9e des pesticides
The long duration cryogenic system of the OLIMPO balloon--borne experiment: design and in--flight performance
We describe the design and in--flight performance of the cryostat and the
self-contained He refrigerator for the OLIMPO balloon--borne experiment,
a spectrophotometer to measure the Sunyaev-Zel'dovich effect in clusters of
galaxies.
The He refrigerator provides the 0.3 K operation temperature for the
four arrays of kinetic inductance detectors working in 4 bands centered at 150,
250, 350 and 460 GHz. The cryostat provides the 1.65 K base temperature for the
He refrigerator, and cools down the reimaging optics and the filters
chain at about 2 K.
The integrated system was designed for a hold time of about 15 days, to
achieve the sensitivity required by the planned OLIMPO observations, and
successfully operated during the first long-duration stratospheric flight of
OLIMPO in July 2018.
The cryostat features two tanks, one for liquid nitrogen and the other one
for liquid helium. The long hold time has been achieved by means of custom
stiff G10 fiberglass tubes support, which ensures low thermal conductivity and
remarkable structural stiffness; multi--layer superinsulation, and a vapour
cooled shield, all reducing the heat load on the liquid helium tank.
The system was tested in the lab, with more than 15 days of unmanned
operations, and then in the long duration balloon flight in the stratosphere.
In both cases, the detector temperature was below 300 mK, with thermal
stability better than 0.5 mK.
The system also operated successfully in the long duration stratospheric
balloon flight
Multiwavelength characterisation of an ACT-selected, lensed dusty star-forming galaxy at z=2.64
We present \ci\,(2--1) and multi-transition CO observations of a dusty
star-forming galaxy, ACT\,J2029+0120, which we spectroscopically confirm to lie
at \,=\,2.64. We detect CO(3--2), CO(5--4), CO(7--6), CO(8--7), and
\ci\,(2--1) at high significance, tentatively detect HCO(4--3), and place
strong upper limits on the integrated strength of dense gas tracers (HCN(4--3)
and CS(7--6)). Multi-transition CO observations and dense gas tracers can
provide valuable constraints on the molecular gas content and excitation
conditions in high-redshift galaxies. We therefore use this unique data set to
construct a CO spectral line energy distribution (SLED) of the source, which is
most consistent with that of a ULIRG/Seyfert or QSO host object in the taxonomy
of the \textit{Herschel} Comprehensive ULIRG Emission Survey. We employ RADEX
models to fit the peak of the CO SLED, inferring a temperature of T117 K
and cm, most consistent with a ULIRG/QSO object
and the presence of high density tracers. We also find that the velocity width
of the \ci\ line is potentially larger than seen in all CO transitions for this
object, and that the ratio is also larger
than seen in other lensed and unlensed submillimeter galaxies and QSO hosts; if
confirmed, this anomaly could be an effect of differential lensing of a shocked
molecular outflow.Comment: Accepted for publication in Ap
Survey strategy optimization for the Atacama Cosmology Telescope
In recent years there have been significant improvements in the sensitivity
and the angular resolution of the instruments dedicated to the observation of
the Cosmic Microwave Background (CMB). ACTPol is the first polarization
receiver for the Atacama Cosmology Telescope (ACT) and is observing the CMB sky
with arcmin resolution over about 2000 sq. deg. Its upgrade, Advanced ACTPol
(AdvACT), will observe the CMB in five frequency bands and over a larger area
of the sky. We describe the optimization and implementation of the ACTPol and
AdvACT surveys. The selection of the observed fields is driven mainly by the
science goals, that is, small angular scale CMB measurements, B-mode
measurements and cross-correlation studies. For the ACTPol survey we have
observed patches of the southern galactic sky with low galactic foreground
emissions which were also chosen to maximize the overlap with several galaxy
surveys to allow unique cross-correlation studies. A wider field in the
northern galactic cap ensured significant additional overlap with the BOSS
spectroscopic survey. The exact shapes and footprints of the fields were
optimized to achieve uniform coverage and to obtain cross-linked maps by
observing the fields with different scan directions. We have maximized the
efficiency of the survey by implementing a close to 24 hour observing strategy,
switching between daytime and nighttime observing plans and minimizing the
telescope idle time. We describe the challenges represented by the survey
optimization for the significantly wider area observed by AdvACT, which will
observe roughly half of the low-foreground sky. The survey strategies described
here may prove useful for planning future ground-based CMB surveys, such as the
Simons Observatory and CMB Stage IV surveys.Comment: 14 Pages, 9 Figures, 4 Table
SWIPE: a bolometric polarimeter for the Large-Scale Polarization Explorer
The balloon-borne LSPE mission is optimized to measure the linear
polarization of the Cosmic Microwave Background at large angular scales. The
Short Wavelength Instrument for the Polarization Explorer (SWIPE) is composed
of 3 arrays of multi-mode bolometers cooled at 0.3K, with optical components
and filters cryogenically cooled below 4K to reduce the background on the
detectors. Polarimetry is achieved by means of large rotating half-wave plates
and wire-grid polarizers in front of the arrays. The polarization modulator is
the first component of the optical chain, reducing significantly the effect of
instrumental polarization. In SWIPE we trade angular resolution for
sensitivity. The diameter of the entrance pupil of the refractive telescope is
45 cm, while the field optics is optimized to collect tens of modes for each
detector, thus boosting the absorbed power. This approach results in a FWHM
resolution of 1.8, 1.5, 1.2 degrees at 95, 145, 245 GHz respectively. The
expected performance of the three channels is limited by photon noise,
resulting in a final sensitivity around 0.1-0.2 uK per beam, for a 13 days
survey covering 25% of the sky.Comment: In press. Copyright 2012 Society of Photo-Optical Instrumentation
Engineers. One print or electronic copy may be made for personal use only.
Systematic reproduction and distribution, duplication of any material in this
paper for a fee or for commercial purposes, or modification of the content of
the paper are prohibite
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