379 research outputs found
Equivalent circuit modeling to design a dual-band dual linear-to-circular polarizer surface
The working principle of a thin dual-band dual-linear to circular polarizer is presented here. This polarizer not only converts incident linearly polarized (LP) waves to circularly polarized (CP) waves in two frequency bands, but it also reverses the handedness of each signal. The electromagnetic behavior of the cell is carefully analyzed and two equivalent circuit models (ECMs) are presented to model the responses of
the cell to linearly polarized waves at normal incidence. The ECMs show how utilizing interlayer coupling can be leveraged to achieve reversed CP senses in two bands using a compact design. Analytical formulas are presented to provide initial values of the ECM components including the mutual coupling inductances. We present measurement results that agree well with the full-wave simulation and the ECM results, thus validating the proposed ECM model.info:eu-repo/semantics/acceptedVersio
Probing spectral properties of radio-quiet quasars searched for optical microvariability-II
In the context of AGN unification scheme rapid variability properties play an
important role in understanding any intrinsic differences between sources in
different classes. In this respect any clue based on spectral properties will
be very useful toward understanding the mechanisms responsible for the origin
of rapid small scale optical variations, or microvariability. Here we have
added spectra of 46 radio-quiet quasars (RQQSOs) and Seyfert 1 galaxies to
those of our previous sample of 37 such objects, all of which had been
previously searched for microvariability. We took new optical spectra of 33
objects and obtained 13 others from the literature. Their \hbeta and \mgii
emission lines were carefully fit to determine line widths (FWHM) as well as
equivalent widths (EW) due to the broad emission line components. The line
widths were used to estimate black hole masses and Eddington ratios, .
Both EW and FWHM are anticorrelated with . Nearly all trends were in
agreement with our previous work, although the tendency for sources exhibiting
microvariability to be of lower luminosity was not confirmed. Most importantly,
this whole sample of EW distributions provides no evidence for the hypothesis
that a weak jet component in the radio quiet AGNs is responsible for their
microvariability.Comment: 15 pages, 9 figures, 6 tables, Accepted in MNRAS main journa
Age-specifi c and sex-specifi c adult mortality risk in India in 2014: analysis of 0·27 million nationally surveyed deaths and demographic estimates from 597 districts
Background As child mortality decreases rapidly worldwide, premature adult mortality is becoming an increasingly
important contributor to global mortality. Any possible worldwide reduction of premature adult mortality before the
age of 70 years will depend on progress in India. Indian districts increasingly have responsibility for implementing
public health programmes. We aimed to assess age-specifi c and sex-specifi c adult mortality risks in India at the
district level.
Methods We analysed data from fi ve national surveys of 0∙27 million adult deaths at an age of 15–69 years together
with 2014 demographic data to estimate age-specifi c and sex-specifi c adult mortality risks for 597 districts. Cause of
death data were drawn from the verbal autopsies in the Registrar General of India’s ongoing Million Death Study.
Findings In 2014, about two-fi fths of India’s men aged 15–69 years lived in the 253 districts where the conditional
probability of a man dying at these ages exceeded 50%, and more than a third of India’s women aged 15–69 years lived
in the 222 districts where the conditional probability of a woman dying exceeded 40%. The probabilities of a man or
woman dying by the age of 70 years in high-mortality districts was 62% and 54%, respectively, whereas the probability
of a man or woman dying by the age of 70 years in low-mortality districts was 40% and 30%, respectively. The roughly
10-year survival gap between high-mortality and low-mortality districts was nearly as extreme as the survival gap between
the entire Indian population and people living in high-income countries. Adult mortality risks at ages 15–69 years was
highest in east India and lowest in west India, by contrast with the north–south divide for child mortality. Vascular
disease, tuberculosis, malaria and other infections, and respiratory diseases accounted for about 60% of the absolute
gap in adult mortality risk at ages 15–69 years between high-mortality and low-mortality districts. Most of the variation
in adult mortality could not be explained by known determinants or risk factors for premature mortality.
Interpretation India’s large variation in adult mortality by district, notably the higher death rates in eastern India,
requires further aetiological research, particularly to explore whether high levels of adult mortality risks from
infections and non-communicable diseases are a result of historical childhood malnutrition and infection. Such
research can be complemented by an expanded coverage of known eff ective interventions to reduce adult mortality,
especially in high-mortality district
Conditional Deletion of Sost in MSC‐derived lineages Identifies Specific Cell Type Contributions to Bone Mass and B Cell Development
Sclerostin (Sost) is a negative regulator of bone formation and blocking its function via antibodies has shown great therapeutic promise by increasing both bone mass in humans and animal models. Sclerostin deletion in Sost knockout mice (Sost‐/‐) causes high bone mass (HBM) similar to Sclerosteosis patients. Sost‐/‐ mice have been shown to display an up to 300% increase in bone volume/total volume (BV/TV), relative to aged matched controls, and it has been postulated that the main source of skeletal Sclerostin is the osteocyte. To understand the cell‐type specific contributions to the HBM phenotype described in Sost‐/‐ mice, as well as to address the endocrine and paracrine mode of action of sclerostin, we examined the skeletal phenotypes of conditional Sost loss‐of‐function (SostiCOIN/iCOIN) mice with specific deletions in (1) the limb mesenchyme (Prx1‐Cre; targets osteoprogenitors and their progeny); (2) mid‐stage osteoblasts and their progenitors (Col1‐Cre); (3) mature osteocytes (Dmp1‐Cre) and (4) hypertrophic chondrocytes and their progenitors (ColX‐Cre). All conditional alleles resulted in significant increases in bone mass in trabecular bone in both the femur and lumbar vertebrae, but only Prx1‐Cre deletion fully recapitulated the amplitude of the HBM phenotype in the appendicular skeleton and the B cell defect described in the global knockout. Despite wildtype expression of Sost in the axial skeleton of Prx1‐Cre deleted mice, these mice also had a significant increase in bone mass in the vertebrae, but the Sclerostin released in circulation by the axial skeleton did not affect bone parameters in the appendicular skeleton. Also, both Col1 and Dmp1 deletion resulted in a similar 80% significant increase in trabecular bone mass, but only Col1 and Prx1 deletion resulted in a significant increase in cortical thickness. We conclude that several cell types within the Prx1‐osteoprogenitor derived lineages contribute significant amounts of Sclerostin protein to the paracrine pool of Sost, in bone
Impact of age on NIS2+™ and other non-invasive blood tests for the evaluation of liver disease and detection of at-risk MASH
\ua9 2024 The Author(s)Background & Aims: Robust performance of non-invasive tests (NITs) across ages is critical to assess liver disease among patients with metabolic dysfunction-associated liver disease (MASLD). We evaluated the impact of age on the performance of NIS2+™ vs. other NITs. Methods: An analysis cohort (N = 1,926) with biopsy-proven MASLD was selected among individuals screened for the phase III RESOLVE-IT clinical trial and divided into ≤45, 46–55, 56–64, and ≥65 years groups. To avoid potential confounding effects, a well-balanced cohort (n = 708; n = 177/age group) was obtained by applying a propensity score-matching algorithm to the analysis cohort. Baseline values of biomarkers and NITs were compared across age groups using one-way ANOVA, and the impact of age and histology were compared through three-way ANOVA. The impact of age on NIT performance for the detection of at-risk metabolic dysfunction-associated steatohepatitis (MASH; MASLD activity score [MAS] ≥4 and fibrosis stage [F] ≥2) was also evaluated. Results: Age did not affect the distributions of NIS2+™ and APRI (aspartate aminotransferase-to-platelet ratio index), but significantly (p <0.0001) impacted those of NFS (NAFLD fibrosis score), FIB-4 (Fibrosis-4 index), and Enhanced Liver Fibrosis (ELF™) score. NIS2+™ was the only NIT on which fibrosis and MAS exerted a moderate to large effect. While the impact of fibrosis on APRI was moderate, that of MAS was low. The impact of age on FIB-4 and NFS was larger than that of fibrosis. NIS2+™ exhibited the highest AUROC values for detecting at-risk MASH across age groups, with stable performances irrespective of cut-offs. Conclusions: NIS2+™ was not significantly impacted by age and was sensitive to both fibrosis and MAS grade, demonstrating a robust performance to rule in/out at-risk MASH with fixed cut-offs. Impact and Implications: While metabolic dysfunction-associated steatotic liver disease (MASLD) can affect individuals of all ages, patient age could represent an important confounding factor when interpreting non-invasive test (NIT) results, highlighting the need for reliable and efficient NITs that are not impacted by age and that could be interpreted with fixed cut-offs, irrespective of patient age. We report the impact of age on different well-established NITs – among those tested, only two panels, NIS2+™ and APRI, were not impacted by age and can be used and interpreted independently of patient age. NIS2+™ was also sensitive to both fibrosis and MAS, further confirming its efficiency for the detection of the composite endpoint of at-risk MASH and its potential as a valuable candidate for large-scale implementation in clinical practice and clinical trials
Localization of a gene for nonsyndromic renal hypodysplasia to chromosome 1p32-33.
Nonsyndromic defects in the urinary tract are the most common cause of end-stage renal failure in children and account for a significant proportion of adult nephropathy. The genetic basis of these disorders is not fully understood. We studied seven multiplex kindreds ascertained via an index case with a nonsyndromic solitary kidney or renal hypodysplasia. Systematic ultrasonographic screening revealed that many family members harbor malformations, such as solitary kidneys, hypodysplasia, or ureteric abnormalities (in a total of 29 affected individuals). A genomewide scan identified significant linkage to a 6.9-Mb segment on chromosome 1p32-33 under an autosomal dominant model with reduced penetrance (peak LOD score 3.5 at D1S2652 in the largest kindred). Altogether, three of the seven families showed positive LOD scores at this interval, demonstrating heterogeneity of the trait (peak HLOD 3.9, with 45% of families linked). The chromosome 1p32-33 interval contains 52 transcription units, and at least 23 of these are expressed at stage E12.5 in the murine ureteric bud and/or metanephric mesenchyme. These data show that autosomal dominant nonsyndromic renal hypodysplasia and associated urinary tract malformations are genetically heterogeneous and identify a locus for this common cause of human kidney failure
Optical microvariability properties of BALQSOs
We present optical light curves of 19 radio quiet (RQ) broad absorption line
(BAL) QSOs and study their rapid variability characteristics. Systematic CCD
observations, aided by a careful data analysis procedure, have allowed us to
clearly detect any such microvariability exceeding 0.01--0.02 mag. Our
observations cover a total of 13 nights (~72 hours) with each quasar monitored
for about 4 hours on a given night. Our sample size is a factor of three larger
than the number of radio-quiet BALQSOs previously searched for
microvariability. We introduce a scaled F-test statistic for evaluating the
presence of optical microvariability and demonstrate why it is generally
preferable to the statistics usually employed for this purpose. Considering
only unambiguous detections of microvariability we find that ~11 per cent of
radio-quiet BALQSOs (two out of 19 sources) show microvariability for an
individual observation length of about 4 hr. This new duty cycle of 11 per cent
is similar to the usual low microvariability fraction of normal RQQSOs with
observation lengths similar to those of ours. This result provides support for
models where radio-quiet BALQSO do not appear to be a special case of the
RQQSOs in terms of their microvariability properties.Comment: 13 pages, 3 figures, 3 tables, accepted for publication in MNRAS main
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