1,497 research outputs found
Universal spectrum for interannual variability in COADS global air and sea-surface temperatures
Continuous periodogram spectral analyses of 28 years (1961-1988) of seasonal (September-November) mean COADS global surface (air and sea) temperature time-series show that the power spectra follow the universal inverse power law form of the statistical normal distribution. An inverse power law form for power spectra of temporal fluctuations implies long-range temperal correlation and is a signature of self-organized criticality. Universal quantification for self-organized criticality presented in this paper is consistent with a recently developed cell dynamical system model for atmospheric flows, which predicts such non-local connections as intrinsic to quantum-like mechanis governing flow dynamics. -from Author
The 404 MHZ wind profiler to observe precipitation
This article delineates the tropical precipitation and classification of precipitating systems into stratiform and convective type, using the UHF wind profiler located at the Indian tropical station Pune (18°32'N, 73°51'E). Under moderate rain conditions the two signals arising due to clear air motions and precipitation are clearly distinguished in the power spectra. An algorithm with suitable methodology has been developed that separates clear air and precipitation echoes when they are clearly distinguishable as seen in the power spectrum. This was tested for various power spectra and found to work well under moderate rain conditions. The sensitivity of the threshold was tested for the precipitation observed on 25 July 2005. In addition, case studies of stratiform rain (precipitation observed over the site on 26 July 2005, 0800 h IST) and convective system (a thunderstorm observed on 16 May 2004) are presented and discussed. An attempt has been made to fit a Gaussian distribution curve to determine the actual Doppler shift and spectral width. The observed convective and stratiform precipitation is described in terms of reflectivity, maximum spectral width and Doppler velocity gradient in the vertical
Scale-size calculations, energy dissipation rates and height coverage of a 404 MHz wind profiler at IMD, Pune
The 404 MHz wind profiler at the India Meteorological Department, Pune, is the first wind profiler of this frequency in India. Therefore, it is necessary to achieve maximum possible height to get valuable data. UHF wind profilers have better height and time resolution, which enables us to make reliable and correct estimations of the wind at various altitudes at regular spacing above the observational site. The height coverage of the profiler depends upon various factors like power aperture product and the operating wavelength vis-avis scale sizes available in the atmosphere. In this study, daily averaged second moment data archived during clear-air conditions have been used to estimate the scale-size parameters in terms of eddy dissipation rates, which explicitly indicates that more height coverage of a profiler depends only on the availability of the scale sizes in the atmosphere to which the radar is sensitive, and that in turn depends on where in the inertial subrange the operating wavelength resides. Power aperture product at various C2n values has been estimated. This note explicitly explains why the height coverage of the wind profiler at Pune is limited to 6-8 km under clear-air conditions
Seasonal, annual and inter-annual features of turbulence parameters over the tropical station Pune (18°32' N, 73°51' E) observed with UHF wind profiler
The present study is specifically focused on the seasonal, annual and inter-annual variations of the refractive index structure parameter (Cn2) using three years of radar observations. Energy dissipation rates (ε) during different seasons for a particular year are also computed over a tropical station, Pune. Doppler spectral width measurements made by the Wind Profiler, under various atmospheric conditions, are utilized to estimate the turbulence parameters. The refractive index structure parameter varies from 10−17.5 to 10−13 m−2/3 under clear air to precipitation conditions in the height region of 1.05 to 10.35 km. During the monsoon months, observed Cn2 values are up to 1–2 orders of magnitude higher than those during pre-monsoon and post-monsoon seasons. Spectral width correction for various non-turbulent spectral broadenings such as beam broadening and shear broadening are made in the observed spectral width for reliable estimation of ε under non-precipitating conditions. It is found that in the lower tropospheric height region, values of ε are in the range of 10−6 to 10−3 m2 s−3. In summer and monsoon seasons the observed values of ε are larger than those in post-monsoon and winter seasons in the lower troposphere. A comparison of Cn2 observed with the wind profiler and that estimated using Radio Sonde/Radio Wind (RS/RW) data of nearby Met station Chikalthana has been made for the month of July 200
Diabetic fetopathy associated with bilateral adrenal hyperplasia and ambiguous genitalia: a case report
<p>Abstract</p> <p>Introduction</p> <p>Many fetal malformations can occur because of maternal diabetes. However, ambiguous genital organs have never been reported as an associated finding in the literature. This is the first report of associated ambiguous genital organ and bilateral adrenal hyperplasia in a case of diabetic fetopathy.</p> <p>Case presentation</p> <p>A 19-year-old Thai primigravida with familial history of diabetes mellitus (DM) was diagnosed as having gestational DM type 2, based on 100 g oral glucose tolerance test, and was poorly controlled with insulin injections. Delayed targeted ultrasonography at 28 weeks gestation revealed multiple fetal anomalies. The woman underwent low transverse cesarean section at 30 weeks gestation due to preterm labor and transverse lie. The newborn with ambiguous genitalia was delivered but expired after birth. Autopsy findings revealed alobar holoprosencephaly, a prominent forehead, hypotelorism, an absent nose, absent bilateral ears, median cleft lip and palate, preaxial polydactyly of the right hand, accessory spleens, single umbilical artery, markedly enlarged adrenal glands and ambiguous external genitalia The subsequent fetal chromosomal study revealed 46,XX.</p> <p>Conclusion</p> <p>We describe a case of diabetic fetopathy with classic facial malformation and preaxial hallucal polydactyly which has been proposed as a marker of diabetic embryopathy. Bilateral adrenal hyperplasia with ambiguous genitalia, an uncommon associated anomaly, was also identified. It is controversial whether adrenal hyperplasia can be a novel feature of diabetic fetopathy or just a coincidental finding. Further observation and adequate investigation are needed in such cases.</p
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Characteristic of enterprise collaboration system and its implementation issues in business management
Collaboration is an extremely useful area for the most of the enterprise systems particularly within Web 2.0 and Enterprise 2.0. The collaboration provides help in enterprise collaboration system (ECS) to achieve the desired goal by unifying completed tasks of employees or people working on a similar or the same task. Thus, the collaboration systems have witnessed significant attention. The ECS provides consistent and off-the-shelf support to processes and managements within organisations. Management techniques of the ECS may be useful to a community which manages ECS systems for collaboration. In this context, this paper focuses on enterprise collaboration system and answers critical questions related to ECS including: 1) what does collaboration really means for an enterprise system; 2) how can the collaboration help to improve internal processes and management of the system; 3) how it is helpful to improve interactions with customers and partners
Molecular Valves for Controlling Gas Phase Transport Made from Discrete Angstrom-Sized Pores in Graphene
An ability to precisely regulate the quantity and location of molecular flux
is of value in applications such as nanoscale 3D printing, catalysis, and
sensor design. Barrier materials containing pores with molecular dimensions
have previously been used to manipulate molecular compositions in the gas
phase, but have so far been unable to offer controlled gas transport through
individual pores. Here, we show that gas flux through discrete angstrom-sized
pores in monolayer graphene can be detected and then controlled using
nanometer-sized gold clusters, which are formed on the surface of the graphene
and can migrate and partially block a pore. In samples without gold clusters,
we observe stochastic switching of the magnitude of the gas permeance, which we
attribute to molecular rearrangements of the pore. Our molecular valves could
be used, for example, to develop unique approaches to molecular synthesis that
are based on the controllable switching of a molecular gas flux, reminiscent of
ion channels in biological cell membranes and solid state nanopores.Comment: to appear in Nature Nanotechnolog
Whole-Body Hypothermia, Cerebral Magnetic Resonance Biomarkers, and Outcomes in Neonates With Moderate or Severe Hypoxic-Ischemic Encephalopathy Born at Tertiary Care Centers vs Other Facilities: A Nested Study Within a Randomized Clinical Trial
IMPORTANCE:
The association between place of birth and hypothermic neuroprotection after hypoxic-ischemic encephalopathy (HIE) in low- and middle-income countries (LMICs) is unknown.
OBJECTIVE:
To ascertain the association between place of birth and the efficacy of whole-body hypothermia for protection against brain injury measured by magnetic resonance (MR) biomarkers among neonates born at a tertiary care center (inborn) or other facilities (outborn). Design, Setting, and
PARTICIPANTS:
This nested cohort study within a randomized clinical trial involved neonates at 7 tertiary neonatal intensive care units in India, Sri Lanka, and Bangladesh between August 15, 2015, and February 15, 2019. A total of 408 neonates born at or after 36 weeks' gestation with moderate or severe HIE were randomized to receive whole-body hypothermia (reduction of rectal temperatures to between 33.0 °C and 34.0 °C; hypothermia group) for 72 hours or no whole-body hypothermia (rectal temperatures maintained between 36.0 °C and 37.0 °C; control group) within 6 hours of birth, with follow-up until September 27, 2020. Exposure: 3T MR imaging, MR spectroscopy, and diffusion tensor imaging.
MAIN OUTCOMES AND MEASURES:
Thalamic N-acetyl aspartate (NAA) mmol/kg wet weight, thalamic lactate to NAA peak area ratios, brain injury scores, and white matter fractional anisotropy at 1 to 2 weeks and death or moderate or severe disability at 18 to 22 months.
RESULTS:
Among 408 neonates, the mean (SD) gestational age was 38.7 (1.3) weeks; 267 (65.4%) were male. A total of 123 neonates were inborn and 285 were outborn. Inborn neonates were smaller (mean [SD], 2.8 [0.5] kg vs 2.9 [0.4] kg; P = .02), more likely to have instrumental or cesarean deliveries (43.1% vs 24.7%; P = .01), and more likely to be intubated at birth (78.9% vs 29.1%; P = .001) than outborn neonates, although the rate of severe HIE was not different (23.6% vs 17.9%; P = .22). Magnetic resonance data from 267 neonates (80 inborn and 187 outborn) were analyzed. In the hypothermia vs control groups, the mean (SD) thalamic NAA levels were 8.04 (1.98) vs 8.31 (1.13) among inborn neonates (odds ratio [OR], -0.28; 95% CI, -1.62 to 1.07; P = .68) and 8.03 (1.89) vs 7.99 (1.72) among outborn neonates (OR, 0.05; 95% CI, -0.62 to 0.71; P = .89); the median (IQR) thalamic lactate to NAA peak area ratios were 0.13 (0.10-0.20) vs 0.12 (0.09-0.18) among inborn neonates (OR, 1.02; 95% CI, 0.96-1.08; P = .59) and 0.14 (0.11-0.20) vs 0.14 (0.10-0.17) among outborn neonates (OR, 1.03; 95% CI, 0.98-1.09; P = .18). There was no difference in brain injury scores or white matter fractional anisotropy between the hypothermia and control groups among inborn or outborn neonates. Whole-body hypothermia was not associated with reductions in death or disability, either among 123 inborn neonates (hypothermia vs control group: 34 neonates [58.6%] vs 34 [56.7%]; risk ratio, 1.03; 95% CI, 0.76-1.41), or 285 outborn neonates (hypothermia vs control group: 64 neonates [46.7%] vs 60 [43.2%]; risk ratio, 1.08; 95% CI, 0.83-1.41).
CONCLUSIONS AND RELEVANCE:
In this nested cohort study, whole-body hypothermia was not associated with reductions in brain injury after HIE among neonates in South Asia, irrespective of place of birth. These findings do not support the use of whole-body hypothermia for HIE among neonates in LMICs.
TRIAL REGISTRATION:
ClinicalTrials.gov Identifier: NCT02387385
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