697 research outputs found
Single-mode sapphire fiber Bragg grating
We present here the inscription of single-mode waveguides with Bragg gratings
in sapphire. The waveguide Bragg gratings have a novel multi-layer depressed
cladding design in the 1550 nm telecommunications waveband. The Bragg gratings
have a narrow bandwidth (<0.5 nm) and have survived annealing at 1000{\deg}C.
The structures are inscribed with femtosecond laser direct writing, using
adaptive beam shaping with a non-immersion objective. A single-mode sapphire
fiber Bragg grating is created by writing a waveguide with a Bragg grating
within a 425 {\mu}m diameter sapphire optical fiber, providing significant
potential for accurate remote sensing in ultra-extreme environments.Comment: Submitted to Optica 12 November 202
Free androgen index and leptin are the most prominent endocrine predictors of ovarian response during clomiphene citrate induction of ovulation in normogonadotropic oligoamenorrheic infertility
We have previously demonstrated that obese hyperandrogenic amenorrheic women are less likely to ovulate after clomiphene citrate (CC) medication. The present study was designed to identify whether additional endocrine screening characteristics, all potentially involved in ovarian dysfunction in 182 normogonadotropic oligoamenorrheic infertile women, are associated with ovarian response, which may improve overall prediction of CC-resistant anovulation. Standardized endocrine screening took place before initiation of CC medication (50 mg/day; increasing doses up to 150 mg/day if required) from cycle days 3-7. Screening included serum assays for fasting insulin and glucose, insulin-like growth factor I (IGF-I), IGF-binding protein-1 (IGFBP-1), IGFBP-3, free IGF-I, inhibin B, leptin, and vascular endothelial growth factor. Forty-two women (22% of the total group) did not ovulate at the end of follow-up (a total number of 325 cycles were analyzed). Fasting serum insulin, insulin/glucose ratio, IGFBP-1, and leptin were all significantly different in univariate analyses (P ≤ 0.02), comparing CC responders vs. nonresponders. Forward stepwise multivariate analyses in combination with factors reported earlier for prediction of patients remaining anovulatory after CC revealed a prediction model including 1) free androgen index (FAI = testosterone/sex hormone-binding globulin ratio), 2) cycle history (oligomenorrhea or amenorrhea), 3) leptin level, and 4) mean ovarian volume. These data suggest that decreased insulin sensitivity, hyperandrogenemia, and obesity, all associated with polycystic ovary syndrome, are prominent factors involved in ovarian dysfunction, preventing these ovaries from responding to stimulation by raised endogenous FSH levels due to CC medication. By using leptin instead of body mass index or waist to hip ratio, the previous model for prediction of patients remaining anovulatory aider CC medication could be slightly improved (area under the curve from 0.82-0.85). This may indicate that leptin is more directly involved in ovarian dysfunction in these patients. The capability of insulin and IGFBP-1 to predict patients who remain anovulatory after CC disappears when FAT enters into the model due to a significant correlation between FAT and these endocrine parameters. This suggests that markers for insulin sensitivity (e.g. IGFBP-1 and insulin) are associated with abnormal ovarian function through its correlation with androgens, whereas leptin is directly involved in ovarian dysfunction
Evaluation of elicitation methods to quantify Bayes linear models
The Bayes linear methodology allows decision makers to express their subjective beliefs and adjust these beliefs as observations are made. It is similar in spirit to probabilistic Bayesian approaches, but differs as it uses expectation as its primitive. While substantial work has been carried out in Bayes linear analysis, both in terms of theory development and application, there is little published material on the elicitation of structured expert judgement to quantify models. This paper investigates different methods that could be used by analysts when creating an elicitation process. The theoretical underpinnings of the elicitation methods developed are explored and an evaluation of their use is presented. This work was motivated by, and is a precursor to, an industrial application of Bayes linear modelling of the reliability of defence systems. An illustrative example demonstrates how the methods can be used in practice
A possible mechanism for cold denaturation of proteins at high pressure
We study cold denaturation of proteins at high pressures. Using
multicanonical Monte Carlo simulations of a model protein in a water bath, we
investigate the effect of water density fluctuations on protein stability. We
find that above the pressure where water freezes to the dense ice phase
( kbar), the mechanism for cold denaturation with decreasing
temperature is the loss of local low-density water structure. We find our
results in agreement with data of bovine pancreatic ribonuclease A.Comment: 4 pages for double column and single space. 3 figures Added
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High-precision optical fiber sensing beyond 1000{\deg}C
Sapphire fiber can withstand around 2000{\deg}C, but it is multimoded, giving
poor precision sensors. We demonstrate a single-mode sapphire fiber Bragg
grating temperature sensor operating up to 1200{\deg}C. The repeatability above
1000{\deg}C is within {\pm}0.08%.Comment: 4 Pages, 5 Figure
Using fractional exhaled nitric oxide (FeNO) to diagnose steroid-responsive disease and guide asthma management in routine care
Acknowledgements We thank Robin Taylor for his informative thinking and publications on FeNO, which have helped to influence and direct the thinking of the authors. Funding Extraction of the real-life dataset was funded by Research in Real Life Limited, the analysis of the dataset and the writing of this manuscript were co-funded (50:50) by Research in Real Life Limited and Aerocrine.Peer reviewedPublisher PD
Sustainable Finance Ratings as the Latest Symptom of “Rating Addiction”
Using the widely accepted but rarely articulated concept of ‘rating addiction’, this piece aims to examine the recent entrance of the credit rating agencies into the sustainable finance field against the backdrop of ‘rating addiction’. Once the concept of ‘rating addiction’ is positioned, the effects of the addiction can be witnessed by even just a cursory glance at the history of the credit rating agencies, particularly their recent history. On that basis, this article provides a warning for regulators and the field with regards to the potentially negative effect that credit rating agencies can have upon the ever-growing and socially-important sustainable finance sector. Additionally, assessing the aptitude of the agencies in this sector, in comparison to the sector’s utilisation of their products, may provide further evidence of a system addicted to ratings
The coronal line regions of planetary nebulae NGC6302 and NGC6537: 3-13um grating and echelle spectroscopy
We report on advances in the study of the cores of NGC6302 and NGC6537 using
infrared grating and echelle spectroscopy. In NGC6302, emission lines from
species spanning a large range of ionization potential, and in particular
[SiIX]3.934um, are interpreted using photoionization models (including CLOUDY),
which allow us to reestimate the central star's temperature to be about
250000K. All of the detected lines are consistent with this value, except for
[AlV] and [AlVI]. Aluminium is found to be depleted to one hundredth of the
solar abundance, which provides further evidence for some dust being mixed with
the highly ionized gas (with photons harder than 154eV). A similar depletion
pattern is observed in NGC6537. Echelle spectroscopy of IR coronal ions in
NGC6302 reveals a stratified structure in ionization potential, which confirms
photoionization to be the dominant ionization mechanism. The lines are narrow
(< 22km/s FWHM), with no evidence of the broad wings found in optical lines
from species with similar ionization potentials, such as [NeV]3426A. We note
the absence of a hot bubble, or a wind blown bipolar cavity filled with a hot
plasma, at least on 1'' and 10km/s scales. We also provide accurate new
wavelengths for several of the infrared coronal lines observed with the
echelle.Comment: Accepted for publication in MNRA
Years off Your Life? The Effects of Homicide on Life Expectancy by Neighborhood and Race/Ethnicity in Los Angeles County
Homicide is one of the leading causes of death in Los Angeles County and is known to be elevated in low-income urban neighborhoods and in black males. However, because homicide occurs primarily among young adults, mortality rate statistics may underrepresent its importance. We estimated the impact of homicide on life expectancy by demographic group and geographic area in Los Angeles County, 2001–2006. Life expectancy estimates were calculated using mortality records and population estimates for Los Angeles County. Cause elimination techniques were used to estimate the impact of homicide on life expectancy. Homicide was estimated to reduce life expectancy by 0.4 years for Los Angeles County residents and by 2.1 years for black males. The impact of homicide on life expectancy was higher in low-income neighborhoods. In some low-income urban neighborhoods, homicide was estimated to decrease life expectancy in black males by nearly 5 years. Homicide causes substantial reductions in life expectancy in Los Angeles County. Its impact is magnified among black males and in low-income urban areas, underscoring the need for homicide reduction in urban centers
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