1,475 research outputs found
Seasonal variation in the incidence of preeclampsia and eclampsia in tropical climatic conditions
<p>Abstract</p> <p>Background</p> <p>Observational studies have demonstrated various correlations between hypertensive disorders of pregnancy and different weather parameters. We aim to study if a correlation exists between the incidence of eclampsia and pre-eclampsia and various weather parameters in the tropical coastal city of Mumbai which has the distinction of having relatively uniform meteorological variables all throughout the year, except for the monsoon season.</p> <p>Methods</p> <p>We retrospectively analysed data from a large maternity centre in Mumbai, India over a period of 36 months from March 1993 to February 1996, recording the incidence of preeclampsia and eclampsia. Meteorological data was acquired from the regional meteorological centre recording the monthly average temperature, humidity, barometric pressure and rainfall during the study period. Study period was then divided into two climate conditions: monsoon season (June to August) and dry season September to May. The incidence of preeclampsia and eclampsia and the meteorological differences between the two seasons were compared.</p> <p>Results</p> <p>Over a 36-month period, a total of 29562 deliveries were recorded, of which 1238 patients developed preeclampsia (4.18%) and 34 developed eclampsia (0.11%). The incidence of preeclampsia did not differ between the monsoon and the dry season (4.3% vs. 4.15%, p = 0.5). The incidence of eclampsia was significantly higher in the monsoon (0.2% vs. 0.08%, p = 0.01). The monsoon was significantly cooler (median maximum temperature 30.7°C vs. 32.3°C, p = 0.01), more humid (median relative humidity 85% vs. 70%, p = 0.0008), and received higher rainfall (median 504.9 mm vs. 0.3 mm, p = 0.0002) than the rest of the year. The median barometric pressure (1005 mb) during the monsoon season was significantly lower than the rest of the year (1012 mb, p < 0.0001).</p> <p>Conclusion</p> <p>In the tropical climate of Mumbai, the incidence of eclampsia is significantly higher in monsoon, when the weather is cooler and humid with a lower barometric pressure than the rest of the year. This effect is not seen with preeclampsia. This strengthens the association of low temperature and high humidity with triggering of eclampsia.</p
Ipsilateral vagotomy to unilaterally ovariectomized pre-pubertal rats modifies compensatory ovarian responses
The present study evaluates the participation of the vagus nerve in pre-pubertal rats with unilateral ovariectomy on puberty onset, and on progesterone, testosterone and estradiol serum levels, and the compensatory responses of the ovary. Unilateral vagotomy did not modify the onset of puberty in unilaterally ovariectomized rats. Ovulation rates of animals with the left vagus nerve sectioned and the left ovary in-situ was lower than in rats with only unilateral ovariectomy. Sectioning the left vagus to 32-day old rats with the left ovary in-situ resulted in lower compensatory ovarian hypertrophy than in rats with right unilateral ovariectomy. Twenty-eight or 32-day old animals with sectioning of the right vagus nerve and the right ovary in situ showed higher compensatory ovulation. Twenty-eight -day old rats with the right ovary in situ had higher progesterone and testosterone levels than animals of the same age with the left ovary in-situ. Compared to animals with the right ovary in situ, animals treated at 32-days of age, sectioning the ipsi-lateral vagus nerve resulted in higher progesterone levels. Higher progesterone levels were observed in 28- and 32 days old rats with the left ovary in situ and left vagus nerve sectioned. Thirty-two day old animals with the right ovary in situ and right vagus nerve sectioned had higher progesterone levels than rats of the same age with the left ovary in situ and left vagus nerve sectioned. Left vagotomy to 28-day old rats with the left ovary in situ resulted in higher testosterone levels, a reverse response to that observed in animals with sectioning of the right vagus and the right ovary in situ. Thirty-two day old rats with the left ovary in situ and left vagus nerve sectioned showed lower testosterone levels than animals without vagotomy and with the left ovary in situ
Estimating magnetic filling factors from simultaneous spectroscopy and photometry : disentangling spots, plage, and network
A.C.C. acknowledges support from the Science and Technology Facilities Council (STFC) consolidated grant number ST/R000824/1.State-of-the-art radial velocity (RV) exoplanet searches are limited by the effects of stellar magnetic activity. Magnetically active spots, plage, and network regions each have different impacts on the observed spectral lines and therefore on the apparent stellar RV. Differentiating the relative coverage, or filling factors, of these active regions is thus necessary to differentiate between activity-driven RV signatures and Doppler shifts due to planetary orbits. In this work, we develop a technique to estimate feature-specific magnetic filling factors on stellar targets using only spectroscopic and photometric observations. We demonstrate linear and neural network implementations of our technique using observations from the solar telescope at HARPS-N, the HK Project at the Mt. Wilson Observatory, and the Total Irradiance Monitor onboard SORCE. We then compare the results of each technique to direct observations by the Solar Dynamics Observatory. Both implementations yield filling factor estimates that are highly correlated with the observed values. Modeling the solar RVs using these filling factors reproduces the expected contributions of the suppression of convective blueshift and rotational imbalance due to brightness inhomogeneities. Both implementations of this technique reduce the overall activity-driven rms RVs from 1.64 to 1.02 m s(-1), corresponding to a 1.28 m s(-1) reduction in the rms variation. The technique provides an additional 0.41 m s(-1) reduction in the rms variation compared to traditional activity indicators.PostprintPeer reviewe
Surface Chemistry of Perfluoropolyethers and Hydrogenated Analogs: Are Studies of Model Compounds Useful?
We have studied adsorption, desorption, and decomposition of ethers on Ru(001), an atomically-smooth metal surface. We have compared diethers with monoethers, and fluorinated ethers with hydrogenated ethers. The number of ether linkages does not strongly influence adsorption bond strength, nor the extent of decomposition. Fluorination does weaken the adsorption bond strength and prevents decomposition. These studies suggest that the surface properties of monomeric ethers can be used to predict properties of oligomeric, and perhaps even polymeric, ethers
Analysis of opo cis-regulatory landscape uncovers Vsx2 requirement in early eye morphogenesis
The self-organized morphogenesis of the vertebrate optic cup entails coupling the activation of the retinal gene regulatory network to the constriction-driven infolding of the retinal epithelium. Yet the genetic mechanisms underlying this coordination remain largely unexplored. Through phylogenetic footprinting and transgenesis in zebrafish, here we examine the cis-regulatory landscape of opo, an endocytosis regulator essential for eye morphogenesis. Among the different conserved enhancers identified, we isolate a single retina-specific element (H6_10137) and show that its activity depends on binding sites for the retinal determinant Vsx2. Gain- and loss-of-function experiments and ChIP analyses reveal that Vsx2 regulates opo expression through direct binding to this retinal enhancer. Furthermore, we show that vsx2 knockdown impairs the primary optic cup folding. These data support a model by which vsx2, operating through the effector gene opo, acts as a central transcriptional node that coordinates neural retina patterning and optic cup invagination in zebrafish.info:eu-repo/semantics/publishedVersio
An ultra-short period rocky super-Earth orbiting the G2-star HD 80653
Ultra-short period (USP) planets are a class of exoplanets with periods
shorter than one day. The origin of this sub-population of planets is still
unclear, with different formation scenarios highly dependent on the composition
of the USP planets. A better understanding of this class of exoplanets will,
therefore, require an increase in the sample of such planets that have accurate
and precise masses and radii, which also includes estimates of the level of
irradiation and information about possible companions. Here we report a
detailed characterization of a USP planet around the solar-type star HD 80653
EP 251279430 using the K2 light curve and 108 precise radial
velocities obtained with the HARPS-N spectrograph, installed on the Telescopio
Nazionale Galileo. From the K2 C16 data, we found one super-Earth planet
() transiting the star on a short-period orbit
( d). From our radial velocity measurements, we
constrained the mass of HD 80653 b to . We also
detected a clear long-term trend in the radial velocity data. We derived the
fundamental stellar parameters and determined a radius of
and mass of , suggesting that HD 80653, has an age of Gyr. The bulk
density ( g cm) of the planet is consistent with
an Earth-like composition of rock and iron with no thick atmosphere. Our
analysis of the K2 photometry also suggests hints of a shallow secondary
eclipse with a depth of 8.13.7 ppm. Flux variations along the orbital
phase are consistent with zero. The most important contribution might come from
the day-side thermal emission from the surface of the planet at K.Includes STFC
An 11 Earth-mass, Long-period Sub-Neptune Orbiting a Sun-like Star
Although several thousands of exoplanets have now been detected and
characterized, observational biases have led to a paucity of long-period,
low-mass exoplanets with measured masses and a corresponding lag in our
understanding of such planets. In this paper we report the mass estimation and
characterization of the long-period exoplanet Kepler-538b. This planet orbits a
Sun-like star (V = 11.27) with M_* = 0.892 +/- (0.051, 0.035) M_sun and R_* =
0.8717 +/- (0.0064, 0.0061) R_sun. Kepler-538b is a 2.215 +/- (0.040, 0.034)
R_earth sub-Neptune with a period of P = 81.73778 +/- 0.00013 d. It is the only
known planet in the system. We collected radial velocity (RV) observations with
HIRES on Keck I and HARPS-N on the TNG. We characterized stellar activity by a
Gaussian process with a quasi-periodic kernel applied to our RV and cross
correlation function full width at half maximum (FWHM) observations. By
simultaneously modeling Kepler photometry, RV, and FWHM observations, we found
a semi-amplitude of K = 1.68 +/- (0.39, 0.38) m s^-1 and a planet mass of M_p =
10.6 +/- (2.5, 2.4) M_earth. Kepler-538b is the smallest planet beyond P = 50 d
with an RV mass measurement. The planet likely consists of a significant
fraction of ices (dominated by water ice), in addition to rocks/metals, and a
small amount of gas. Sophisticated modeling techniques such as those used in
this paper, combined with future spectrographs with ultra high-precision and
stability will be vital for yielding more mass measurements in this poorly
understood exoplanet regime. This in turn will improve our understanding of the
relationship between planet composition and insolation flux and how the rocky
to gaseous transition depends on planetary equilibrium temperature
The joy of ruling: an experimental investigation on collective giving
We analyse team dictator games with different voting mechanisms in the laboratory. Individuals vote to select a donation for all group members. Standard Bayesian analysis makes the same prediction for all three mechanisms: participants should cast the same vote regardless of the voting mechanism used to determine the common donation level. Our experimental results show that subjects fail to choose the same vote. We show that their behaviour is consistent with a joy of ruling: individuals get an extra utility when they determine the voting outcome
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