585 research outputs found
VLA 1.4GHz observations of the GOODS-North Field: Data Reduction and Analysis
We describe deep, new, wide-field radio continuum observations of the Great
Observatories Origins Deep Survey -- North (GOODS-N) field. The resulting map
has a synthesized beamsize of ~1.7" and an r.m.s. noise level of ~3.9uJy/bm
near its center and ~8uJy/bm at 15', from phase center. We have cataloged 1,230
discrete radio emitters, within a 40' x 40' region, above a 5-sigma detection
threshold of ~20uJy at the field center. New techniques, pioneered by Owen &
Morrison (2008), have enabled us to achieve a dynamic range of 6800:1 in a
field that has significantly strong confusing sources. We compare the 1.4-GHz
(20-cm) source counts with those from other published radio surveys. Our
differential counts are nearly Euclidean below 100uJy with a median source
diameter of ~1.2". This adds to the evidence presented by Owen & Morrison
(2008) that the natural confusion limit may lie near ~1uJy. If the Euclidean
slope of the counts continues down to the natural confusion limit as an
extrapolation of our log N - log S, this indicates that the cutoff must be
fairly sharp below 1uJy else the cosmic microwave background temperature would
increase above 2.7K at 1.4 GHz.Comment: Accepted for publication in ApJS. 16 pages, 19 figures. Radio data
and source list can be found at http://www.ifa.hawaii.edu/~morrison/GOODSN
TRIS I: Absolute Measurements of the Sky Brightness Temperature at 0.6, 0.82 and 2.5 GHz
At frequencies close to 1 GHz the sky diffuse radiation is a superposition of
radiation of Galactic origin, the 3 K Relic or Cosmic Microwave Background
Radiation, and the signal produced by unresolved extragalactic sources. Because
of their different origin and space distribution the relative importance of the
three components varies with frequency and depends on the direction of
observation. With the aim of disentangling the components we built TRIS, a
system of three radiometers, and studied the temperature of the sky at , and GHz using geometrically scaled antennas
with identical beams (HPBW = ). Observations
included drift scans along a circle at constant declination
which provided the dependence of the sky signal on the
Right Ascension, and absolute measurement of the sky temperature at selected
points along the same scan circle. TRIS was installed at Campo Imperatore (lat.
= N, long.= , elevation = 2000 m a.s.l.) in
Central Italy, close to the Gran Sasso Laboratory.Comment: Accepted for publication in The Astrophysical Journa
TRIS III: the diffuse galactic radio emission at
We present values of temperature and spectral index of the galactic diffuse
radiation measured at 600 and 820 MHz along a 24 hours right ascension circle
at declination . They have been obtained from a subset of
absolute measurements of the sky temperature made with TRIS, an experiment
devoted to the measurement of the Cosmic Microwave Background temperature at
decimetric-wavelengths with an angular resolution of about .
Our analysis confirms the preexisting picture of the galactic diffuse
emission at decimetric wavelength and improves the accuracy of the measurable
quantities. In particular, the signal coming from the halo has a spectral index
in the range above 600 MHz, depending on the sky position. In the
disk, at TRIS angular resolution, the free-free emission accounts for the 11%
of the overall signal at 600 MHz and 21% at 1420 MHz. The polarized component
of the galactic emission, evaluated from the survey by Brouw and Spoelstra,
affects the observations at TRIS angular resolution by less than 3% at 820 MHz
and less than 2% at 600 MHz. Within the uncertainties, our determination of the
galactic spectral index is practically unaffected by the correction for
polarization.
Since the overall error budget of the sky temperatures measured by TRIS at
600 MHz, that is 66 mK(systematic)18 mK (statistical), is definitely smaller
than those reported in previous measurements at the same frequency, our data
have been used to discuss the zero levels of the sky maps at 150, 408, 820 and
1420 MHz in literature. Concerning the 408 MHz survey, limiting our attention
to the patch of sky corresponding to the region observed by TRIS, we suggest a
correction of the base-level of K.Comment: Accepted for publication in the Astrophysical Journa
Immunological characteristics of non-intensive care hospitalized COVID-19 patients: A preliminary report
Abstract: The outbreak of coronavirus disease 2019 (COVID-19) is posing a threat to global health.
This disease has different clinical manifestations and different outcomes. The immune response
to the novel 2019 coronavirus is complex and involves both innate and adaptive immunity. In
this context, cell-mediated immunity plays a vital role in effective immunity against SARS-CoV-2.
Significant differences have been observed when comparing severe and non-severe patients. Since
these immunological characteristics have not been fully elucidated, we aimed to use cluster analysis
to investigate the immune cell patterns in patients with COVID-19 who required hospitalization but
not intensive care. We identified four clusters of different immunological patterns, the worst being
characterized by total lymphocytes, T helper lymphocytes CD4+
(CD4+
), T cytotoxic lymphocytes
CD8+
(CD8+
) and natural killer (NK) cells below the normal range, together with natural killer
lymphocyte granzyme < 50% (NK granzyme+
) and antibody-secreting plasma cells (ASCs) equal to 0
with fatal outcomes. In the worst group, 50% of patients died in the intensive care unit. Moreover,
a negative trend was found among four groups regarding total lymphocytes, CD4+
, CD8+ and B
lymphocytes (p < 0.001, p < 0.005, p < 0.000, p < 0.044, respectively). This detailed analysis of immune
changes may have prognostic value. It may provide a new perspective for identifying subsets of
COVID-19 patients and selecting novel prospective treatment strategies. Notwithstanding these
results, this is a preliminary report with a small sample size, and our data may not be generalizable.
Further cohort studies with larger samples are necessary to quantify the prognostic value’s weight,
according to immunological changes in COVID-19 patients, for predicting prognoses and realizing
improvements in clinical conditions
Deciphering the local Interstellar spectra of primary cosmic ray species with HelMod
Local interstellar spectra (LIS) of primary cosmic ray (CR) nuclei, such as
helium, oxygen, and mostly primary carbon are derived for the rigidity range
from 10 MV to ~200 TV using the most recent experimental results combined with
the state-of-the-art models for CR propagation in the Galaxy and in the
heliosphere. Two propagation packages, GALPROP and HelMod, are combined into a
single framework that is used to reproduce direct measurements of CR species at
different modulation levels, and at both polarities of the solar magnetic
field. The developed iterative maximum-likelihood method uses GALPROP-predicted
LIS as input to HelMod, which provides the modulated spectra for specific time
periods of the selected experiments for model-data comparison. The interstellar
and heliospheric propagation parameters derived in this study are consistent
with our prior analyses using the same methodology for propagation of CR
protons, helium, antiprotons, and electrons. The resulting LIS accommodate a
variety of measurements made in the local interstellar space (Voyager 1) and
deep inside the heliosphere at low (ACE/CRIS, HEAO-3) and high energies
(PAMELA, AMS-02).Comment: 13 pages, 13 figures, 6 tables, ApJ in press. arXiv admin note: text
overlap with arXiv:1704.0633
HelMod in the works: from direct observations to the local interstellar spectrum of cosmic-ray electrons
The local interstellar spectrum (LIS) of cosmic-ray (CR) electrons for the
energy range 1 MeV to 1 TeV is derived using the most recent experimental
results combined with the state-of-the-art models for CR propagation in the
Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod,
are combined to provide a single framework that is run to reproduce direct
measurements of CR species at different modulation levels, and at both
polarities of the solar magnetic field. An iterative maximum-likelihood method
is developed that uses GALPROP-predicted LIS as input to HelMod, which provides
the modulated spectra for specific time periods of the selected experiments for
model-data comparison. The optimized HelMod parameters are then used to adjust
GALPROP parameters to predict a refined LIS with the procedure repeated subject
to a convergence criterion. The parameter optimization uses an extensive data
set of proton spectra from 1997-2015. The proposed CR electron LIS accommodates
both the low-energy interstellar spectra measured by Voyager 1 as well as the
high-energy observations by PAMELA and AMS-02 that are made deep in the
heliosphere; it also accounts for Ulysses counting rate features measured out
of the ecliptic plane. The interstellar and heliospheric propagation parameters
derived in this study agree well with our earlier results for CR protons,
helium nuclei, and anti-protons propagation and LIS obtained in the same
framework.Comment: 11 pages, 14 figures, 4 tables; ApJ, in pres
Methodological Issues in the Clinical Validation of Biomarkers for Alzheimer's Disease : The Paradigmatic Example of CSF
The use of biomarkers is profoundly transforming medical research and practice. Their adoption has triggered major advancements in the field of Alzheimer's disease (AD) over the past years. For instance, the analysis of the cerebrospinal fluid (CSF) and neuroimaging changes indicative of neuronal loss and amyloid deposition has led to the understanding that AD is characterized by a long preclinical phase. It is also supporting the transition towards a biology-grounded framework and definition of the disease. Nevertheless, though sufficient evidence exists about the analytical validity (i.e., accuracy, reliability, and reproducibility) of the candidate AD biomarkers, their clinical validity (i.e., how well the test measures the clinical features, and the disease or treatment outcomes) and clinical utility (i.e., if and how the test improves the patient's outcomes, confirms/changes the diagnosis, identifies at-risk individuals, influences therapeutic choices) have not been fully proven. In the present review, some of the methodological issues and challenges that should be addressed in order to better appreciate the potential benefits and limitations of AD biomarkers are discussed. The ultimate goal is to stimulate a constructive discussion aimed at filling the existing gaps and more precisely defining the directions of future research. Specifically, four main aspects of the clinical validation process are addressed and applied to the most relevant CSF biomarkers: (1) the definition of reference values; (2) the identification of reference standards for the disease of interest (i.e., AD); (3) the inclusion within the diagnostic process; and (4) the statistical process supporting the whole framework
Indications to total thyroidectomy for multinodular goiter in old patients
Background: In Western society, the percentage of elderly people is
continually growing. The prevalence of goiter increases with the age and it
is estimated that 90% of women over 60 years old and 60% of men over
80 years old have a relief of thyroid nodules. This has great importance for
these patients, because the incidence of malignant transformation is higher
than younger ones and these are often tumor very aggressive patterns. If
thyroidectomy is indicated for patients with suspected neoplasm and severe
obstructive symptoms, their surgery should not be delayed since a late
urgent operation could raise morbidity and mortality risk. The main
indications for young patients are due to obstructive and metabolic causes
over and above suspected cancer.
Total thyroidectomy is considered by many authors as the treatment of
choice.
Materials and methods: 75 elderly patients were submitted to
thyroidectomy. The indications were metabolic (42.6%), obstructive (32%)
and for suspected cancer (25.4%).
Results: The most frequent complications observed with respect to young
patients in different series have been cardiovascular, pulmonary or
urological. Regarding the complications directly related to thyroidectomy,
there were no differences compared to younger groups, except transient
complications (hypoparathyroidism, seroma). In our experience, the main
complication was represented by hypocalcemia (30.6%), permanent in 8% of
cases. Cancer was relieved in 21.3% of cases.
Prognosis has been excellent in most cases, with immediate remission of
symptoms related to thyrotoxicosis and to tracheal and esophageal
compression in almost all symptomatic patients.
Conclusions: Age is an independent prognostic factor for cancers. It has
been demonstrated that elderly patients with PTC that are operated have
better prognosis and quality of life due to the resolution of dyspnea and
dysphagia. In our experience, we think that age is not a contraindication to
thyroid surgery
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