Determination of In-Situ Stress at Desilting Chamber of Punatsangchhu Hydroelectric Project (Bhutan), to Reconfirm Its Orientation Influenced by Topography — A Case Study

Punatsangchhu Hydroelectric Project stage-I was conceptualized in Wangdue- Phodrang district of Bhutan for harnessing the hydro-power potentiality of Punatsangchhu River. Regionally the project area is located within a part of a gneissic terrain of Tethyan Belt of Bhutan Himalayas. The project envisages construction of 195m high concrete gravity dam across the river Punatsangchhu. For Desilting chamber and Powerhouse, it is always desirable to carry out in-situ stress measurement in such huge underground openings for designing of the support types. The stability of the underground cavern gets enhanced if the long axis of the cavern is oriented along or sub-parallel to that of maximum principal stress. National Institute of Rock Mechanics, a premier Research Institute under Ministry of Mines, Government of India, carried out stress measurements at RD 100m and RD 150m inside an exploratory drift approaching towards desilting chamber with a rock cover of 100m. This test was required to freeze the orientation of desilting chamber vis. a vis. orientation of maximum compression (σH) which was found to be N 150°. As it was only 100 to 150 m away from the portal, a topography effect on the orientation of (σH) was not completely ruled out. So when the adit to Desilting chamber reached at RD 360m with a rock cover of 410m, it is necessary to carry out stress measurement at RD 360m to confirm the results of earlier tests at RD100m and RD 150m to find out the influence of topography on which the present paper is based was primarily for determination of in-situ stress measurements. The stress orientation as evaluated at RD 360m reconfirms the orientations revealed from earlier stress measurements at RD 100 and RD 150m.Thus it is recommended to freeze the direction of Desilting chamber along N 150°. It also confirms that the earlier stress measurement results do not suffer from topography related influence

Prevalence of subclinical hypothyroidism in children and adolescents of northern Andhra Pradesh population and its association with hyperlipidemia

Background: The thyroid dysfunction particularly, subclinical hypothyroidism (SCH) is quite a common clinical condition in paediatric population but there is limited data available regarding its prevalence in children and adolescents in our population. The present study was aimed to know the prevalence of thyroid dysfunction particularly SCH in children and adolescents of northern Andhra Pradesh population and its association with hyperlipidemia.Methods: A retrospective study of 600 subjects (Children=272, Adolescents=328) between 6-19 years of age were included and the following parameters were examined: age, sex, total triiodothyronine (tT3), total tetraiodothyronine (tT4), thyroid stimulating hormone (TSH), total cholesterol, triglycerides (TGL), LDL and HDL cholesterol. The subjects were divided into group I and group II on the basis of age (in years), subjects between 6- ≤12 years age were grouped as group I and 12-≤19 years were as group II.Results: Out of 272 children and 328 adolescents studied, the prevalence of thyroid dysfunction was found to be 9.9% and 10.4 % respectively. The prevalence of subclinical hypothyroidism in children was 7.7% where as 4.9% in adolescents. In both the groups, females were predominantly affected with thyroid dysfunction as compared to males. Significantly elevated serum levels of total cholesterol, TSH and TGL were observed in SCH subjects when compared to euthyroid subjects (p<0.05). Statistically significant lower levels of HDL cholesterol were found in SCH as compared to euthyroids (p<0.05). However, no difference was noticed in the levels of total T3, total T4 and LDL cholesterol between SCH and euthyroids.Conclusions: The prevalence of thyroid dysfunction was found to be 10.2% in study population. SCH was observed in 7.7 % and 4.9% respectively in children and adolescent groups. Subclinical hypothyroidism (SCH) was the most predominant thyroid dysfunction found in our studied population with a prevalence of 6.2% (both children and adolescents). Correction of thyroid dysfunction particularly SCH in early childhood is highly essential to prevent the impairment of psychomotor and cognitive development

Clinical and etiological spectrum of prolonged fever and special reference to HIV patients at a tertiary care centre

Background: Prolonged fever is a diagnostic challenge and will tend to remain so in times to come because of the changing spectrum of etiologies and influence of technology, environmental changes, and many other ill-understood factors which influence the etiological spectrum. Prolonged fever is also undergoing change in its duration. The aim of the present was study to determine the etiologies of prolonged fever in patients in India and to evaluate the clinical and etiological relationship between the diagnosis and patient’s laboratory data.Methods: Patients aged more 13 years with fever >38.3ºC for more than three weeks without apparent source after preliminary investigations were included prospectively over a period of twenty two months. Fever duration, symptom, signs, laboratory investigations and final diagnosis were recorded. The distribution of etiologies and age, fever duration, laboratory examinations, and associated symptoms and signs were analyzed.Results: Out of total of 86 patients were enrolled, fifty one (59.3%) were men. The median age was 28 years (range, 13-65 yr). Among 86 patients, diagnosis could be made in only 69 (80.2%) patients. Infections, neoplasms, NIIDs, miscellaneous causes were responsible for prolonged fever in 42 (48.8%), 18 (20.9%), 6 (7%), and 3 (3.5%) patients respectively. Seveteen (19.8%) cases remained undiagnosed, even after relevant investigations, six of them recovered spontaneously. Tuberculosis (TB) was the cause of prolonged fever in 21 (24.4%) patients.Conclusions: Infections, amongst which tuberculosis, remain the major cause of prolonged fever and its subset: fever of unknown origin (FUO), in this country. The percent of undiagnosed cases appears to be identical worldwide

Enhancement in electron and ion temperatures due to solar flares as measured by SROSS-C2 satellite

The observations on the ionospheric electron and ion temperatures (T<sub>e</sub> and T<sub>i</sub>) measured by the RPA payload aboard the SROSS-C2 satellite have been used to study the effect of solar flares on ionospheric heating. The data on solar flare has been obtained from the National Geophysical Data Center (NGDC) Boulder, Colorado (USA). It has been found that the electron and ion temperatures have a consistent enhancement during the solar flares on the dayside Earth's ionosphere. The estimated enhancement for the average electron temperature is from 1.3 to 1.9 times whereas for ion temperature it is from 1.2 to 1.4 times to the normal days average temperature. The enhancement of ionospheric temperatures due to solar flares is correlated with the diurnal variation of normal days' ionospheric temperatures. The solar flare does not have any significant effect on the nightside ionosphere. A comparison with the temperature obtained from the IRI-95 model also shows a similar enhancement

Dark Matter and Experiments for its Identification

After Fritz Zwicky, through various theoretical models, several dark matter events have been proposed. but none of them is yet discovered. Recent experiment shows that only around 5% of the total matters present in the whole universe are visual. Rest matter is still unknown to us by any present experimental tools. this leads that detection of dark matter is one of the very challenging & curios goal for experimental physicists. For the search of suitable dark matter candidates and for rear physics events, high Purity germanium detectors, Spherical gaseous chamber detector and few more hybrid-detectors are suitable for these purposes. We proposed that any suitable detector hosted under deep sea water will be more effective than the under ground or mountain caverns

Magnetodielectric effect of Graphene-PVA Nanocomposites

Graphene-Polyvinyl alcohol (PVA) nanocomposite films with thickness $120 \mu m$ were synthesized by solidification of PVA in a solution with dispersed graphene nanosheets. Electrical conductivity data were explained as arising due to hopping of carriers between localized states formed at the graphene-PVA interface. Dielectric permittivity data as a function of frequency indicated the occurrence of Debye-type relaxation mechanism. The nanocomposites showed a magnetodielectric effect with the dielectric constant changing by 1.8% as the magnetic field was increased to 1 Tesla. The effect was explained as arising due to Maxwell-Wagner polarization as applied to an inhomogeneous two-dimensional,two-component composite model. This type of nanocomposite may be suitable for applications involving nanogenerators.Comment: 13 pages, 11 figure

Expression Analysis of Novel microRNAs in Rice During High Temperature Stress

MicroRNAs (miRNAs) are small non-coding RNAs which play an important role in regulating the genes involved in plant growth and development. Several studies showed that miRNAs are involved in plants response to different kinds of abiotic stresses also. In our previous study, temperature responsive miRNAs were predicted in O.sativa. 27 miRNAs were predicted to be novel in rice using homology search. In continuation to our previous study, expression of 14 novel miRNAs was done in shoot and root of 13 days old seedlings of five different rice cultivars using real time PCR. Expression these miRNAs was analyzed in control and high temperature stress environment. Out of 14 predicted novel miRNAs, two novel miRNAs- miR157a and miR165a showed expression in all five rice cultivars. Interestingly, miR165a showed a differential expression pattern among heat tolerant (N22, IR64 and Rasi) and susceptible (Vandana and Sampada) cultivars suggesting that it might have specific role in high temperature tolerance

Evaluation of low-energy effective Hamiltonian techniques for coupled spin triangles

Motivated by recent work on Heisenberg antiferromagnetic spin systems on various lattices made up of triangles, we examine the low-energy properties of a chain of antiferromagnetically coupled triangles of half-odd-integer spins. We derive the low-energy effective Hamiltonian to second order in the ratio of the coupling J_2 between triangles to the coupling J_1 within each triangle. The effective Hamiltonian contains four states for each triangle which are given by the products of spin-1/2 states with the states of a pseudospin-1/2. We compare the results obtained by exact diagonalization of the effective Hamiltonian with those obtained for the full Hamiltonian using exact diagonalization and the density-matrix renormalization group method. It is found that the effective Hamiltonian is accurate only for the ground state for rather low values of the ratio J_2 / J_1 and that too for the spin-1/2 case with linear topology. The chain of spin-1/2 triangles shows interesting properties like spontaneous dimerization and several singlet and triplet excited states lying close to the ground state.Comment: Revtex, 11 pages, 11 eps figure

Quasiparticle bandgap engineering of graphene and graphone on hexagonal boron nitride substrate

Graphene holds great promise for post-silicon electronics, however, it faces two main challenges: opening up a bandgap and finding a suitable substrate material. In principle, graphene on hexagonal boron nitride (hBN) substrate provides potential system to overcome these challenges. Recent theoretical and experimental studies have provided conflicting results: while theoretical studies suggested a possibility of a finite bandgap of graphene on hBN, recent experimental studies find no bandgap. Using the first-principles density functional method and the many-body perturbation theory, we have studied graphene on hBN substrate. A Bernal stacked graphene on hBN has a bandgap on the order of 0.1 eV, which disappears when graphene is misaligned with respect to hBN. The latter is the likely scenario in realistic devices. In contrast, if graphene supported on hBN is hydrogenated, the resulting system (graphone) exhibits bandgaps larger than 2.5 eV. While the bandgap opening in graphene/hBN is due to symmetry breaking and is vulnerable to slight perturbation such as misalignment, the graphone bandgap is due to chemical functionalization and is robust in the presence of misalignment. The bandgap of graphone reduces by about 1 eV when it is supported on hBN due to the polarization effects at the graphone/hBN interface. The band offsets at graphone/hBN interface indicate that hBN can be used not only as a substrate but also as a dielectric in the field effect devices employing graphone as a channel material. Our study could open up new way of bandgap engineering in graphene based nanostructures.Comment: 8 pages, 4 figures; Nano Letters, Publication Date (Web): Oct. 25 2011, http://pubs.acs.org/doi/abs/10.1021/nl202725