Gravitational collapse due to dark matter and dark energy in the brane world scenario

Gravitational collapse of FRW brane world embedded in a conformaly flat bulk is considered for matter cloud consists of dark matter and dark energy with equation of state $p=\epsilon \rho$ $(\epsilon<-{1/3})$. The effect of dark matter and dark energy is being considered first separately and then a combination of them both with and without interaction. In some cases the collapse leads to black hole in some other cases naked singularity appears.Comment: 10 Latex Pages, RevTex style, 4 figure

Convergence rate across the Nepal Himalaya and interseismic coupling on the Main Himalayan Thrust: Implications for seismic hazard

We document geodetic strain across the Nepal Himalaya using GPS times series from 30 stations in Nepal and southern Tibet, in addition to previously published campaign GPS points and leveling data and determine the pattern of interseismic coupling on the Main Himalayan Thrust fault (MHT). The noise on the daily GPS positions is modeled as a combination of white and colored noise, in order to infer secular velocities at the stations with consistent uncertainties. We then locate the pole of rotation of the Indian plate in the ITRF 2005 reference frame at longitude = − 1.34° ± 3.31°, latitude = 51.4° ± 0.3° with an angular velocity of Ω = 0.5029 ± 0.0072°/Myr. The pattern of coupling on the MHT is computed on a fault dipping 10° to the north and whose strike roughly follows the arcuate shape of the Himalaya. The model indicates that the MHT is locked from the surface to a distance of approximately 100 km down dip, corresponding to a depth of 15 to 20 km. In map view, the transition zone between the locked portion of the MHT and the portion which is creeping at the long term slip rate seems to be at the most a few tens of kilometers wide and coincides with the belt of midcrustal microseismicity underneath the Himalaya. According to a previous study based on thermokinematic modeling of thermochronological and thermobarometric data, this transition seems to happen in a zone where the temperature reaches 350°C. The convergence between India and South Tibet proceeds at a rate of 17.8 ± 0.5 mm/yr in central and eastern Nepal and 20.5 ± 1 mm/yr in western Nepal. The moment deficit due to locking of the MHT in the interseismic period accrues at a rate of 6.6 ± 0.4 × 10^(19) Nm/yr on the MHT underneath Nepal. For comparison, the moment released by the seismicity over the past 500 years, including 14 M_W ≥ 7 earthquakes with moment magnitudes up to 8.5, amounts to only 0.9 × 10^(19) Nm/yr, indicating a large deficit of seismic slip over that period or very infrequent large slow slip events. No large slow slip event has been observed however over the 20 years covered by geodetic measurements in the Nepal Himalaya. We discuss the magnitude and return period of M > 8 earthquakes required to balance the long term slip budget on the MHT

Quasi-spherical collapse with cosmological constant

The junction conditions between static and non-static space-times are studied for analyzing gravitational collapse in the presence of a cosmological constant. We have discussed about the apparent horizon and their physical significance. We also show the effect of cosmological constant in the collapse and it has been shown that cosmological constant slows down the collapse of matter.Comment: 7 pages, No figures, RevTeX styl

Adventure Tourism – Exploring the Thrill – Seeking Behaviour

This paper explores the developing landscape of adventure tourism and more particularly the growth of extreme adventure activities. It delves into the psychological motivation, personality trait, and social factors that attract participants, alongside the perceived benefits and challenges. The research also probes into the part played by tour operator in this aspect with regard to risk and safety management. This research, both qualitative and quantitative, into the factors influencing one’s participation in adventure tourism is approached through a mixed methodology with the help of a questionnaire. Key themes include excitement, personal growth, and change in lifestyle. The most influential factor is social influence if peers and social media for participation. The project emphasizes a balance between the hunt of excitement and fulfilment on one hand and environmental concern on other. Ultimately it will try to spell out the motivation for the search of adventure and strategies for assuring safety and how these shape the long-term future of adventure tourism

Lateral uniformity of India Plate strength over central and eastern Nepal

The current understanding of the Himalayan lithosphere stems mostly from cross-sections through the range at the longitude of the Kathmandu Basin. In this paper we laterally extend the analyses of structures and rheology along the Nepal Himalayas between the Pokhara valley and the Arun river. We take advantage of available information and a new data set including gravity measurements and a receiver function profile. It appears that the geometry of the Moho inferred from seismological profiles and long-wavelength gravity anomalies does not exhibit major East-West variations within the 350-km-wide study area. Using thermomechanical modelling, we show that the northward deepening of the Moho observed along profiles perpendicular to the main thrust faults can be interpreted simply as the bending of a strong India Plate. This result suggests a gradual mechanical decoupling between the crust and the mantle, leading to a northward decrease of the effective elastic thickness of the Indian lithosphere from∼75 km to∼25 km beneath the Ganga Basin and the Tibetan Plateau, respectively. Our results also confirm (partially) eclogitized lower Indian crust beneath southern Tibet. At shorter wavelengths, the observed gravity profiles exhibit some small lateral variations that can be interpreted in terms of east-west variations of the thickness of subsurface geological structures such as the Ganga Basin and the Tethyan Sedimentary Sequenc

Non-adiabatic collapse of a quasi-spherical radiating star

A model is proposed of a collapsing quasi-spherical radiating star with matter content as shear-free isotropic fluid undergoing radial heat-flow with outgoing radiation. To describe the radiation of the system, we have considered both plane symmetric and spherical Vaidya solutions. Physical conditions and thermodynamical relations are studied using local conservation of momentum and surface red-shift. We have found that for existence of radiation on the boundary, pressure on the boundary is not necessary.Comment: 8 Latex pages, No figures, Revtex styl

Anisotropic Brane Cosmology with Variable GG and Λ\Lambda

In this work, the cosmological implications of brane world scenario are investigated when the gravitational coupling $G$ and the cosmological term $\Lambda$ are not constant but rather there are time variation of them. From observational point of view, these time variations are taken in the form $\frac{\dot{G}}{G}\sim H$ and $\Lambda \sim H^{2}$. The behavior of scale factors and different kinematical parameters are investigated for different possible scenarios where the bulk cosmological constant $\Lambda_{5}$ can be zero, positive or negative.Comment: RevTex, 7 figures, 16 page

Role of inflammation as reflected by serum hsCRP and ferritin level in major depressive disorder

Background: The relationship between depression and inflammation has been strengthened by different studies for which Immune Cytokine Mechanism has been proposed to explain pathogenesis of depression.Methods: The role of inflammation in major depressive disorder (MDD) has been evaluated in this study among 101 patients suffering from MDD along with 106 age and sex matched control subjects. Two well known acute phase reactant proteins namely hsCRP and Ferritin were assayed in all study subjects by Enzyme Immuno Assay method.Results: Concentration of hsCRP in serum was found to be significantly increased in all patients suffering from MDD whereas Ferritin level was found to be significantly decreased in male MDD subjects only (male: 70.6 ng/ml±53.54 ng/ml in MDD vs 100.16 ng/ml±39.93 in controls; female: 38.43 ng/ml±11.2 in MDD vs 39.93 ng/ml±15.0 in controls). There was no significant alteration of the parameters among different grades of MDD. The possibility of these two parameters to be used as biomarkers has also been evaluated by ROC curve.Conclusions: The significant change in hsCRP & Ferritin which is not associated with grade wise alteration suggests that probably inflammation is the early event which causes depression. Therefore no gradual change is observed with increase in severity of the disease. hsCRP can be used as a biomarker of Inflammation in MDD cases

Seismic Imaging of the Main Frontal Thrust in Nepal Reveals a Shallow Décollement and Blind Thrusting

Because great earthquakes in the Himalaya have an average recurrence interval exceeding 500 yr, most of what we know about past earthquakes comes from paleoseismology and tectonic geomorphology studies of the youngest fault system there, the Main Frontal Thrust (MFT). However, these data are sparse relative to fault segmentation and length, and interpretations are often hard to validate in the absence of information about fault geometry. Here, we image the upper two km of strata in the vicinity of the fault tip of the MFT in central Nepal (around the town of Bardibas) applying a pre-stack migration approach to two new seismic reflection profiles that we interpret using quantitative fault-bend folding theory. Our results provide direct evidence that a shallow décollement produces both emergent (Patu thrust) and blind (Bardibas thrust) fault strands. We show that the décollement lies about 2 km below the land surface near the fault tip, and steps down to a regional 5 km deep décollement level to the north. This implies that there is significant variation in the depth of the décollement. We demonstrate that some active faults do not reach the surface, and therefore paleoseismic trenching alone cannot characterize the earthquake history at these locations. Although blind, these faults have associated growth strata that allow us to infer their most recent displacement history. We present the first direct evidence of fault dip on two fault strands of the MFT at depth that can allow terrace uplift measurements to be more accurately converted to fault slip. We identify a beveled erosional surface buried beneath Quaternary sediments, indicating that strath surface formation is modulated by both climate-related base level changes and tectonics. Together, these results indicate that subsurface imaging, in conjunction with traditional paleoseismological tools, can best characterize the history of fault slip in the Himalaya and other similar thrust fault systems