1,071 research outputs found
A fuzzy logic controller based mid-term load forecasting with renewable penetration in Assam, India
An accurate mid-term load forecasting (MTLF) tool is an essential part of power systems planning and sustainable development. In order to compensate the extra uncertainties, the power systems with high renewable penetration need even more accurate MTLF tool. The electric load demand is highly prejudiced by the thermal inertia due to the local climatic factors. Therefore, the accuracy of an MTLF method is highly dependent on the incorporated climatic factors. This paper proposes a fuzzy logic comptroller based MTLF method with renewable penetration. In order to achieve a higher degree of forecasting accuracy proposed method incorporated several climatic factors in the forecasting process. The study is done in Assam, a state of India and the proposed method is utilized to forecast the daily average load demand for one month. The forecasting accuracy of the proposed method is compared with one of most commonly used tool for MTLF called artificial neural network (ANN). The empirical results affirm the superiority of the proposed method over the ANN
A Time-Dependent Radiative Model of HD209458b
We present a time-dependent radiative model of the atmosphere of HD209458b
and investigate its thermal structure and chemical composition. In a first
step, the stellar heating profile and radiative timescales were calculated
under planet-averaged insolation conditions. We find that 99.99% of the
incoming stellar flux has been absorbed before reaching the 7 bar level.
Stellar photons cannot therefore penetrate deeply enough to explain the large
radius of the planet. We derive a radiative time constant which increases with
depth and reaches about 8 hr at 0.1 bar and 2.3 days at 1 bar. Time-dependent
temperature profiles were also calculated, in the limit of a zonal wind that is
independent on height (i.e. solid-body rotation) and constant absorption
coefficients. We predict day-night variations of the effective temperature of
\~600 K, for an equatorial rotation rate of 1 km/s, in good agreement with the
predictions by Showman &Guillot (2002). This rotation rate yields day-to-night
temperature variations in excess of 600 K above the 0.1-bar level. These
variations rapidly decrease with depth below the 1-bar level and become
negligible below the ~5--bar level for rotation rates of at least 0.5 km/s. At
high altitudes (mbar pressures or less), the night temperatures are low enough
to allow sodium to condense into Na2S. Synthetic transit spectra of the visible
Na doublet show a much weaker sodium absorption on the morning limb than on the
evening limb. The calculated dimming of the sodium feature during planetary
transites agrees with the value reported by Charbonneau et al. (2002).Comment: 9 pages, 8 figures, replaced with the revised versio
Transmission spectroscopy of the sodium 'D' doublet in WASP-17b with the VLT
The detection of increased sodium absorption during primary transit implies
the presence of an atmosphere around an extrasolar planet, and enables us to
infer the structure of this atmosphere. Sodium has only been detected in the
atmospheres of two planets to date - HD189733b and HD209458b. WASP-17b is the
least dense planet currently known. It has a radius approximately twice that of
Jupiter and orbits an F6-type star. The transit signal is expected to be about
five times larger than that observed in HD209458b. We obtained 24 spectra with
the GIRAFFE spectrograph on the VLT, eight during transit. The integrated flux
in the sodium doublet at wavelengths 5889.95 and 5895.92 {\AA} was measured at
bandwidths 0.75, 1.5, 3.0, 4.0, 5.0, and 6.0 {\AA}. We find a transit depth of
0.55 \pm 0.13 per cent at 1.5 {\AA}. This suggests that, like HD209458b,
WASP-17b has an atmosphere depleted in sodium compared to models for a
cloud-free atmosphere with solar sodium abundance. We observe a sharp cut-off
in sodium absorption between 3.0 and 4.0 {\AA} which may indicate a layer of
clouds high in the atmosphere.Comment: Amended for typographic conventions following publicatio
Cationic vacancy induced room-temperature ferromagnetism in transparent conducting anatase Ti_{1-x}Ta_xO_2 (x~0.05) thin films
We report room-temperature ferromagnetism in highly conducting transparent
anatase Ti1-xTaxO2 (x~0.05) thin films grown by pulsed laser deposition on
LaAlO3 substrates. Rutherford backscattering spectrometry (RBS), x-ray
diffraction (XRD), proton induced x-ray emission (PIXE), x-ray absorption
spectroscopy (XAS) and time-of-flight secondary ion mass spectrometry
(TOF-SIMS) indicated negligible magnetic contaminants in the films. The
presence of ferromagnetism with concomitant large carrier densities was
determined by a combination of superconducting quantum interference device
(SQUID) magnetometry, electrical transport measurements, soft x-ray magnetic
circular dichroism (SXMCD), XAS, and optical magnetic circular dichroism (OMCD)
and was supported by first-principle calculations. SXMCD and XAS measurements
revealed a 90% contribution to ferromagnetism from the Ti ions and a 10%
contribution from the O ions. RBS/channelling measurements show complete Ta
substitution in the Ti sites though carrier activation was only 50% at 5% Ta
concentration implying compensation by cationic defects. The role of Ti vacancy
and Ti3+ was studied via XAS and x-ray photoemission spectroscopy (XPS)
respectively. It was found that in films with strong ferromagnetism, the Ti
vacancy signal was strong while Ti3+ signal was absent. We propose (in the
absence of any obvious exchange mechanisms) that the localised magnetic
moments, Ti vacancy sites, are ferromagnetically ordered by itinerant carriers.
Cationic-defect-induced magnetism is an alternative route to ferromagnetism in
wide-band-gap semiconducting oxides without any magnetic elements.Comment: 21 pages, 10 figures, to appear in Philosophical Transaction - Royal
Soc.
Compositional Diversity in the Atmospheres of Hot Neptunes, With Application to GJ 436b
Neptune-sized extrasolar planets that orbit relatively close to their host stars—often called hot Neptunes —are common within the known population of exoplanets and planetary candidates. Similar to our own Uranus and Neptune, inefficient accretion of nebular gas is expected produce hot Neptunes whose masses are dominated by elements heavier than hydrogen and helium. At high atmospheric metallicities of 10-10,000 times solar, hot Neptunes will exhibit an interesting continuum of atmospheric compositions, ranging from more Neptune-like, H2-dominated atmospheres to more Venus-like, CO2-dominated atmospheres. We explore the predicted equilibrium and disequilibrium chemistry of generic hot Neptunes and find that the atmospheric composition varies strongly as a function of temperature and bulk atmospheric properties such as metallicity and the C/O ratio. Relatively exotic H2O, CO, CO2, and even O2-dominated atmospheres are possible for hot Neptunes. We apply our models to the case of GJ 436b, where we find that a CO-rich, CH4-poor atmosphere can be a natural consequence of a very high atmospheric metallicity. From comparisons of our results with Spitzer eclipse data for GJ 436b, we conclude that although the spectral fit from the high-metallicity forward models is not quite as good as the best fit obtained from pure retrieval methods, the atmospheric composition predicted by these forward models is more physically and chemically plausible in terms of the relative abundance of major constituents. High-metallicity atmospheres (orders of magnitude in excess of solar) should therefore be considered as a possibility for GJ 436b and other hot Neptunes
Mental health status and perceived burden in caregiving spouses of persons with psychotic illness (a study from India)
Mental illness poses a great deal of burden on other family members, particularly the primary caregiver. In the Indian context for a married person with mental illness, the caregiving burden is usually experienced by the spouse, who is considered to be the ‘natural’ option. This quantitative study used survey methodology to assess caregiving burden in fifty spouses of persons diagnosed with a psychotic illness. Data was collected at a neuro-psychiatric facility in Tiruchirappalli, India. The Depression, Anxiety and Stress Scale and the Burden Assessment Schedule were the instruments administered to assess the mental health status of the spouse and their perceived burden. Findings revealed that the majority of spouses were classified as experiencing ‘severe’ and ‘extremely severe’ in terms of their depression, anxiety and stress levels and ‘high’ in terms of perceived burden. The specific ‘type’ of clinical diagnosis, however, did not differentiate the spouses on the key variables studied. The correlation of these key variables with other background variables has also been examined. The implications of the results of this study for psychosocial intervention have also been discussed in this article
Human annexin A6 interacts with influenza a virus protein M2 and negatively modulates infection
Copyright © 2012, American Society for Microbiology. All Rights ReservedThe influenza A virus M2 ion channel protein has the longest cytoplasmic tail (CT) among the three viral envelope proteins and is well conserved between different viral strains. It is accessible to the host cellular machinery after fusion with the endosomal membrane and during the trafficking, assembly, and budding processes. We hypothesized that identification of host cellular interactants of M2 CT could help us to better understand the molecular mechanisms regulating the M2-dependent stages of the virus life cycle. Using yeast two-hybrid screening with M2 CT as bait, a novel interaction with the human annexin A6 (AnxA6) protein was identified, and their physical interaction was confirmed by coimmunoprecipitation assay and a colocalization study of virus-infected human cells. We found that small interfering RNA (siRNA)-mediated knockdown of AnxA6 expression significantly increased virus production, while its overexpression could reduce the titer of virus progeny, suggesting a negative regulatory role for AnxA6 during influenza A virus infection. Further characterization revealed that AnxA6 depletion or overexpression had no effect on the early stages of the virus life cycle or on viral RNA replication but impaired the release of progeny virus, as suggested by delayed or defective budding events observed at the plasma membrane of virus-infected cells by transmission electron microscopy. Collectively, this work identifies AnxA6 as a novel cellular regulator that targets and impairs the virus budding and release stages of the influenza A virus life cycle.This work was supported by the Research Fund for the Control of Infectious Disease (project 09080892) of the Hong Kong Government, the Area of Excellence Scheme of the University Grants Committee (grant
AoE/M-12/-06 of the Hong Kong Special Administrative Region, China), the French Ministry of Health, the RESPARI Pasteur Network
The thermal emission of the young and massive planet CoRoT-2b at 4.5 and 8 microns
We report measurements of the thermal emission of the young and massive
planet CoRoT-2b at 4.5 and 8 microns with the Spitzer Infrared Array Camera
(IRAC). Our measured occultation depths are 0.510 +- 0.042 % and 0.41 +- 0.11 %
at 4.5 and 8 microns, respectively. In addition to the CoRoT optical
measurements, these planet/star flux ratios indicate a poor heat distribution
to the night side of the planet and are in better agreement with an atmosphere
free of temperature inversion layer. Still, the presence of such an inversion
is not definitely ruled out by the observations and a larger wavelength
coverage is required to remove the current ambiguity. Our global analysis of
CoRoT, Spitzer and ground-based data confirms the large mass and size of the
planet with slightly revised values (Mp = 3.47 +- 0.22 Mjup, Rp = 1.466 +-
0.044 Rjup). We find a small but significant offset in the timing of the
occultation when compared to a purely circular orbital solution, leading to e
cos(omega) = -0.00291 +- 0.00063 where e is the orbital eccentricity and omega
is the argument of periastron. Constraining the age of the system to be at most
of a few hundreds of Myr and assuming that the non-zero orbital eccentricity is
not due to a third undetected body, we model the coupled orbital-tidal
evolution of the system with various tidal Q values, core sizes and initial
orbital parameters. For log(Q_s') = 5 - 6, our modelling is able to explain the
large radius of CoRoT-2b if log(Q_p') <= 5.5 through a transient tidal
circularization and corresponding planet tidal heating event. Under this model,
the planet will reach its Roche limit within 20 Myr at most.Comment: 13 pages, 2 tables, 11 figures. Accepted for publication in Astronomy
and Astrophysic
Estimates of electronic interaction parameters for LaO compounds (=Ti-Ni) from ab-initio approaches
We have analyzed the ab-initio local density approximation band structure
calculations for the family of perovskite oxides, LaO with =Ti-Ni
within a parametrized nearest neighbor tight-binding model and extracted
various interaction strengths. We study the systematics in these interaction
parameters across the transition metal series and discuss the relevance of
these in a many-body description of these oxides. The results obtained here
compare well with estimates of these parameters obtained via analysis of
electron spectroscopic results in conjunction with the Anderson impurity model.
The dependence of the hopping interaction strength, t, is found to be
approximately .Comment: 18 pages; 1 tex file+9 postscript files (appeared in Phys Rev B Oct
15,1996
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