GeoJournal - Basic urban services refer to the important civic services required for the citizens of urban areas and for the functioning of cities viz., water supply, sanitation, waste management,... 相似文献
The relevance of groundwater hydrogeochemistry to explain the occurrence and distribution of arsenic in groundwater is of great interest. The insightful discussions on the control of shallow groundwater (< 50 m) hydrogeochemistry in arsenic mobilization are known to be a viable tool to explain the arsenic menace in shallow groundwater. The present investigation emphasizes the hydrogeochemical driver and/or control over the reductive dissolution of Fe-bearing host minerals and thereby releasing arsenic into the shallow groundwater of the study area. The study suggests that hydrogeochemical evolution is mainly governed by carbonate minerals dissolution, silicate weathering, and competitive ion-exchange processes in the shallow aquifers (< 50 m). The present study also indicates the prevalence of carbonate minerals dissolution over silicate weathering. The emergence of Cl− concentration in the shallow groundwater founds the possibilities of anthropogenic inputs into the shallow aquifers (< 50 m). The reducing environment in shallow aquifers (< 50 m) of the study area is evident in the reductive dissolution of Fe- bearing shallow aquifer minerals which absorb arsenic in the solid phase and mobilize arsenic onto shallow groundwater. The study opted for many statistical approaches to delineate the correlation among major and minor ionic constituents of the groundwater which are very helpful to understand the comprehensive mechanism of arsenic mobilization into shallow groundwater.
Astrophysics - We used modified holographic Ricci dark energy to find anisotropic LRS Bianchi type I cosmological model in five-dimensions based on Lyra geometry. The exact solutions of the... 相似文献
Stresses building up during an earthquake preparation phase also manifest themselves in the form of a so called increased land surface temperature (LST) leading to a thermal precursor prior to the earthquake event. This phenomenon has now been validated by our observations of short-term thermal anomalies detected by infrared satellite sensors for several recent past earthquakes around the world. The rise in infrared radiance temperature was seen to vary between 5 and 12 °C for different earthquakes. We discuss in this paper different explanations for the generation of such anomalies that have been offered. Emission of gases due to the opening and closure of micropores upon induced stresses and also the participation of ground water have been propounded as a possible cause for generation of thermal anomalies. Seismo-ionosphere coupling, by which gases like radon move to the earth–atmosphere interface and cause air ionization thus bringing about a change in air temperature, relative humidity, etc., has been put forth by some workers. A mechanism of low frequency electromagnetic emission was tested and experimented by scientists with rock masses in stressed conditions as those that exist at tectonic locations. The workers proposed the positive hole pair theory, which received support from several scientific groups. Positive holes (sites of electron deficiency) are activated in stressed rocks from pre-existing yet dormant positive hole pairs (PHPs) and their recombination at rock–air interface leads to a LST rise. A combination of remote sensing detection of rock mechanics behavior with a perception of chemistry and geophysics has been applied to propose the remote sensing rock mechanics theory. Remote sensing detections of such anomalies confirm so far proposed lab theories for such a hotly debated field as earthquake precursor study by providing unbiased observations with consistency in time and space distribution. 相似文献
We study the evolution of the configuration entropy of HI distribution in the post-reionization era assuming different time evolution of HI bias.We describe time evolution of linear bias of HI distribution using a simple form b(a)=b0an with different index n.The derivative of the configuration entropy rate is known to exhibit a peak at the scale factor corresponding to theΛ-matter equality in the unbiasedΛCDM model.We show that in theΛCDM model with time-dependent linear bias,the peak shifts to smaller scale factors for negative values of n.This is related to the fact that the growth of structures in the HI density field can significantly slow down even before the onset ofΛdomination in the presence of a strong time evolution of the HI bias.We find that the shift is linearly related to the index n.We obtain the best fit relation between these two parameters and propose that identifying the location of this peak from observations would allow us to constrain the time evolution of HI bias within the framework of theΛCDM model. 相似文献
We have classified a sample of 37,492 objects from SDSS into QSOs, galaxies and stars using photometric data over five wave bands (u, g, r, i and z) and UV GALEX data over two wave bands (near-UV and far-UV) based on a template fitting method. The advantage of this method of classification is that it does not require any spectroscopic data and hence the objects for which spectroscopic data is not available can also be studied using this technique. In this study, we have found that our method is consistent by spectroscopic methods given that their UV information is available. Our study shows that the UV colours are especially important for separating quasars and stars, as well as spiral and starburst galaxies. Thus it is evident that the UV bands play a crucial role in the classification and characterization of astronomical objects that emit over a wide range of wavelengths, but especially for those that are bright at UV. We have achieved the efficiency of 89% for the QSOs, 63% for the galaxies and 84% for the stars. This classification is also found to be in agreement with the emission line diagnostic diagrams. 相似文献
Fast Radio Bursts (FRBs) last for \(\sim \) few milli-seconds and, hence, are likely to arise from the gravitational collapse of supra-massive, spinning neutron stars after they lose the centrifugal support (Falcke & Rezzolla 2014). In this paper, we provide arguments to show that the repeating burst, FRB 121102, can also be modeled in the collapse framework provided the supra-massive object implodes either into a Kerr black hole surrounded by highly magnetized plasma or into a strange quark star. Since the estimated rates of FRBs and SN Ib/c are comparable, we put forward a common progenitor scenario for FRBs and long GRBs in which only those compact remnants entail prompt \(\gamma \)-emission whose kick velocities are almost aligned or anti-aligned with the stellar spin axes. In such a scenario, emission of detectable gravitational radiation and, possibly, of neutrinos are expected to occur during the SN Ib/c explosion as well as, later, at the time of magnetar implosion. 相似文献
We examine the properties of the viscous dissipative accretion flow around rotating black holes in the presence of mass loss. Considering the thin disc approximation, we self-consistently calculate the inflow-outflow solutions and observe that the mass outflow rates decrease with the increase in viscosity parameter (\(\alpha \)). Further, we carry out the model calculation of quasi-periodic oscillation frequency (\(\nu _{\mathrm{QPO}}\)) that is frequently observed in black hole sources and observe that \(\nu ^\mathrm{max}_{\mathrm{QPO}}\) increases with the increase of black hole spin (\(a_k\)). Then, we employ our model in order to explain the High Frequency Quasi-Periodic Oscillations (HFQPOs) observed in black hole source GRO J1655-40. While doing this, we attempt to constrain the range of \(a_k\) based on observed HFQPOs (\(\sim \)300 Hz and \(\sim \)450 Hz) for the black hole source GRO J1655-40. 相似文献
The passive Eastern Continental Margin of India (ECMI) evolved during the break up of India and East Antarctica in the Early Cretaceous. The 85°E ridge is a prominent linear aseismic feature extending from the Afanasy Nikitin Seamounts northward to the Mahanadi basin along the ECMI. Earlier workers have interpreted the ridge to be a prominent hot spot trail. In the absence of conclusive data, the extension of the ridge towards its northern extremity below the thick Bengal Fan sediments was a matter of postulation. In the present study, interpretation of high resolution 2-D reflection data from the Mahanadi Offshore Basin, located in the northern part of the ridge, unequivocally indicates continuation of the ridge across the continent–ocean boundary into the slope and shelf tracts of the ECMI. Its morphology and internal architecture suggest a volcanic plume related origin that can be correlated with the activity of the Kerguelen hot spot in the nascent Indian Ocean. In the continental region, the plume related volcanic activity appears to have obliterated all seismic features typical of continental crust. The deeper oceanic crust, over which the hot spot plume erupted, shows the presence of linear NS aligned basement highs, corresponding with the ridge, underlain by a depressed Moho discontinuity. In the deep oceanic basin, the ridge influences the sediment dispersal pattern from the Early Cretaceous (?)/early part of Late Cretaceous times till the end of Oligocene, which is an important aspect for understanding the hydrocarbon potential of the basin. 相似文献
The provision of urban service and citizens’ satisfaction is an important key issue in urban planning. Importance-performance analysis (IPA) is an effective and widely applicable technique to explore consumer’s satisfaction. IPA helps to prioritize the management strategies for urban services using the IPA. Purpose of the present study is to assess the performance of urban services and citizen’s satisfaction level of Panskura municipality using IPA models and improvement index. A total of 629 valid household responses are collected with the help of the door-to-door primary survey technique. The study reveals that all the selected seven urban services have significant importance-performance gap except water supply. Residents of the Panskura municipality are very much satisfied with the water supply service because of the very minimum improvement score. The combined result of IPA matrices and improvement index suggests residents are dissatisfied to a great extent with the performance of four urban services, i.e. health, economy, transportation and sanitation. These urban services require a problem-solving urgent action for restoration of the performance status. The improvement and prioritization of urban service are also required to fulfil the demand of target groups.