Explore the vast range of titles available.

Changes in rainfall affect drinking water, river and surface runoff, soil moisture, groundwater reserve, electricity generation, agriculture production and ultimately the economy of a country. Trends in rainfall, therefore, are important for examining the impact of climate change on water resources for its planning and management. Here, as analysed from 119 years of rainfall measurements at 16 different rain gauge stations across northeast India, a significant change in the rainfall pattern is evident after the year 1973, with a decreasing trend in rainfall of about 0.42 ± 0.024 mm dec−1. The wettest place of the world has shifted from Cherrapunji (CHE) to Mawsynram (MAW) (separated by 15 km) in recent decades, consistent with long-term rainfall changes in the region. The annual mean accumulated rainfall was about 12 550 mm at MAW and 11 963 mm at CHE for the period 1989-2010, as deduced from the available measurements at MAW. The changes in the Indian Ocean temperature have a profound effect on the rainfall in the region, and the contribution from the Arabian Sea temperature and moisture is remarkable in this respect, as analysed with a multivariate regression procedure for the period 1973-2019. The changes in land cover are another important aspect of this shift in rainfall pattern, as we find a noticeable reduction in vegetation area in northeast India in the past two decades, implying the human influence on recent climate change.

Interactions between midlatitude disturbances and the monsoonal circulation are significant for the Indian summer monsoon (ISM) rainfall. This paper presents examples of monsoon–midlatitude linkage through anticyclonic Rossby wave breaking (RWB) over West Asia during June, July and August of the years 1998–2010. RWB events over West Asia are identified by the inversion of the potential vorticity air mass at three different isentropic levels (340, 350, and 360 K) using daily NCEP–NCAR reanalysis. It is observed that RWB took place over West Asia before/during breaks in the ISM. Further, these events occur on the anticyclonic shear side of the subtropical jet, where the gradient of the zonal wind is found to be high. RWB is responsible for the southward movement of high potential vorticity air from the westerly jet, leading to the formation of a blocking high over the Arabian region. In turn, this blocking high advects and causes the descent of upper tropospheric cold and dry air towards Central India. Such an air mass with low moist static energy inhibits deep monsoonal convection and thereby leads to a dry spell. In fact, we find that RWB induced blocking over West Asia to be one of the major causes of dry spell/break episodes in ISM. Additionally, the presence of cold air over Central India reduces the north–south thermal contrast over the monsoon region thereby modifying the local Hadley circulation over the region.

This study explores the potential of atmospheric moisture content, its transport and its divergence over the ocean and land as proxies for the variability of Indian summer monsoon rainfall (ISMR) for the period 1950-2019. The analyses using multiple linear regression reveal that the interannual and intraseasonal variability of ISMR and the mean ISMR is largely controlled by Arabian Sea moisture flux and Ganga river basin moisture content, and these parameters exhibit statistically significant high correlations in most regions. The regression model and the parameters are statistically significant and the model could explain rainfall variability of about 12%-50% in various regions. The model shows a false alarm rate (FAR) of 0.25-0.45 and a probability of detection (POD) of 0.43-0.50 for wet years in West Central, North West and North Central India. The FAR and POD are about 0.06-0.32 and 0.60-0.70, respectively for dry years in those regions. The model reproduces flood and drought years of about 32%-50% and 55%-70% in those regions. Also, the moisture indices could clearly identify the majority of wet and dry years that occurred during the period. The ISMR variability associated with moisture indices is unaffected by El Niño Southern Oscillation. Henceforth, this study demonstrates the significance of atmospheric moisture on regional rainfall distribution and suggests that these parameters can be used in both statistical and dynamical models to better predict monsoon and global precipitation.

Industrial emissions of ozone depleting substances (ODSs) during the second half of the twentieth century have led to one of the most visible human impacts on the Earth: the Antarctic ozone hole. The ozone loss intensified in the 1980s and reached the level of saturation (i.e., complete loss of ozone) due to the high levels of ODSs in the atmosphere. Significant changes in the southern hemispheric climate have been observed in the past decades due to this unprecedented ozone loss. Although the most recent studies suggest healing in the Antarctic ozone hole, the status of ozone in the loss saturation layer (~13–21 km) has not been discussed in detail. Here, a comprehensive analysis of vertical, spatial and temporal evolution of ozone loss saturation (ozone mixing ratio ≤ 0.1 ppmv) in the Antarctic vortex using high resolution measurements for the 1979–2017 period reveals that the loss saturation began in 1987 and continued to occur in all winters thereafter, except in the major warming winters of 1988 and 2002. However, our analysis shows a clear reduction in the frequency of occurrence of ozone loss saturation over the period 2001–2017 consistently throughout various datasets (e.g., ozonesonde and satellite measurements of ozone profiles and total columns), thereby revealing the emergence of an important milestone in ozone recovery. An emerging recovery in the Antarctic ozone hole The frequency of near-complete loss of ozone has become lower since 2001, suggesting that the recovery of the Antarctic ozone hole is underway. A team led by Jayanarayanan Kuttippurath at the Centre for Oceans, Rivers, Atmosphere and Land Sciences, Indian Institute of Technology Kharagpur, India, examined observations of ozone from meteorological balloons and satellites and found that, at 13–21 km above Antarctica, ozone began to reach near-zero levels as early as 1987 and continuing until the early 2000s. Since then, the frequency of near-zero ozone levels has begun to lessen. The ozone record is short and noisy, but the researchers clearly show that the peak of the ozone hole has ceased to worsen and is improving. Although full recovery of the ozone hole will take far longer, the findings are consistent with an expectation of ozone recovery following the reduction in ozone depleting substances mandated by the Montreal Protocol.

Despite having excellent osteoconductivity and biocompatibility, hydroxyapatite (HA) exhibits inadequate mechanical properties and bacterial susceptibility, which limits its medical applications. The present study aims to fabricate 3-aminopropyltrimethoxysilane (3-APTMS) functionalized gold (Au)-silver (Ag) nanoparticles incorporated in hydroxyapatite bioceramics to overcome this limitation. Thermogravimetric analysis (TGA), X-Ray diffraction, and scanning electron microscopy were carried out to understand the physical and chemical characteristics of the material. The maximum values of fracture toughness, hardness, compressive and flexural strength were measured for HA-10 Au/Ag NPs. Both quantitative and qualitative analyses of antibacterial behavior revealed that the adhesion of gram-positive ( Staphylococcu aureus ) and gram-negative ( Eschericia coli ) bacterial cells were reduced significantly after the incorporation of Au/Ag NPs as compared with the HA control. In addition, the effect of Au/Ag NPs incorporation on the cellular response was observed for the MG63 cell line. Both the quantitative and qualitative results indicate significantly enhanced cell proliferation with the incorporation of Au/Ag NPs as compared to HA. The addition of Au/Ag NPs in HA provides a material with appropriate mechanical, antibacterial, and cellular responses for further consideration. Graphical abstract

Purple membrane (PM) has been extracted and purified from archaebacteria for thin film development. The purified purple membrane is isolated in 1 % polyvinyl alcohol solution for making thin film within gelatin and organically modified silicate matrices. For thin film within gelatin matrix, homogenized purple membrane suspension is mixed with 8 % gelatin and poured into a specially designed block with desired thickness of spacer having hydrophobicity followed by gelatinization of the same over home-made thermostatic control unit at 38 °C. The gelatinized matrix is then allowed to dry under controlled conditions of humidity and temperature. The films of varying thicknesses ranging between 40, 50, and 60 μ are used for photo-electrochemical measurements. The results on photo-electrochemistry of non-oriented purple membrane film provides valuable information on the generation of forward (light on) and backward (light off) photocurrent as a function of: (a) applied potential and (b) film thickness. An increase in applied negative potential increases the amplitude of photocurrent whereas decrease in film thickness facilitates the reversibility of photocurrent response.

Designing the self-configured framework of nanoporous lattices, to assemble bifunctional nanomaterials on solid substrates, retaining the well-defined nanogeometry is the chief objectives of the present study. Organofunctionalised alkoxysilanes (3-aminopropyltrimethoxysilane (APTMS), 2-(3, 4-epoxycyclohexyl) ethyltrimethoxysilane (EETMS)) containing the functional groups, amino, epoxy, hydroxyl etc., are the potential candidates for the fabrication of nanostructured and monolayered assembly of mono (PdNPs) and bimetallic (Au@PdNPs, Ag@PdNPs) nanomaterials, via sol–gel processing, in aqueous and non-aqueous media with thickness in the range 6–8 nm. The interactions between the silane coupling agents are studied using dynamic light scattering (DLS) technique. The range of hydrodynamic radii ( R H ) in different solvents is attributed to the multistage directional alignment of colloidal solutions of alkoxysilane functionalized nanomaterials on solid substrates. The difference in the tendency of the formation of aggregate structures is a function of solvent, critical micelle concentration (CMC) of the surfactant. 2-propanol based colloidal dispersions of nanoparticles are exceptionally more homogenously dispersed and have relatively lower z -average values, as the possibility of cluster formation is reduced. The micellar behavior of APTMS and reactivity of EETMS directs the formulation of the stable and catalytically dynamic nanomaterials. The sensitivity of monolayer deposition lies with the water content of the micellar solution, therefore uniform coating is promised by employing nonaqueous solvents (0.66 nm) which tend to slowdown the rate of condensation. Pore diameter and overall architecture are achieved due to less branched structures of the EETMS and APTMS, which are acting as scaffolds for thin film fabrication, and relative rates of evaporation of solvents. Highlights Solvent dependent formulation of palladium based bimetallic nanomaterials Micellar behavior of organofunctionalized alkoxysilanes confirms the stabilisation of nanoparticles Self assembling of bifunctional nanoparticles within nanoporous matrix of organosilanes with retention in nanogeometry Homogenous and monolayer deposition to generate ordered pattern of nanoporous thin films

This manuscript describes fabrication of a cross-linked and nanoengineered three-dimensional matrix of polymersomes for encapsulation of macromolecular cargo such as enzymes. Our approach involves the integration of glucose oxidase (GOx) enzyme into networks of a polysaccharide-silica matrix. Direct chemical cross-linking occurs between the residual groups of alginate polymer and the alkoxysilane moieties in a palladium nanoparticle dispersion; a transformation in the chemical configuration of the alginate hydrogel along with precise control over the pore size distribution facilitate immobilization of enzyme. The activity of the polymersomes was evaluated by enzymatic oxidation of the glucose substrate in phosphate buffer through loading different concentrations of GOx. In situ generated H 2 O 2 was decomposed by the as-synthesized Prussian blue nanoparticles, which serve as an excellent peroxidase mimetic. The functional enzyme polymersome system was utilized for in vitro detection of blood glucose values. Graphic abstract

Strong bidirectional internal solitary waves (ISWs) generate from a shallow channel between Car Nicobar and Chowra Islands of Nicobar Islands, India, and propagate toward the Andaman Sea (eastward) and Bay of Bengal (westward). Batti Malv Island separates this shallow channel into two ridges, north of Batti Malv (NBM) and south of Batti Malv (SBM). First, this study identifies the prominent mode-1 and mode-2 ISWs emerging from NBM and SBM using synthetic aperture radar images and then explores their generation mechanism(s) using a nonlinear, unstructured, and nonhydrostatic model, SUNTANS. During spring tide, flow over NBM is supercritical with respect to mode-1 internal wave. Model simulations reveal that mode-1 ISWs are generated at NBM by a “lee wave mechanism” and propagate both in the east and west directions depending on the tidal phases. However, the flow over SBM is subcritical with respect to mode-1 internal wave. The bidirectional propagating mode-1 ISWs evolve from a long-wave disturbance induced by “upstream influence.” But, during spring tide, with an increased tidal flow over SBM, it is observed that the westward propagating ISWs are formed by a dispersed hydraulic jump observed over the ridge. Moreover, the bidirectional mode-2 waves from SBM are generated by a lee wave mechanism. An energy budget comparison reveals that the region surrounding NBM is efficient in radiating low-mode baroclinic energy (0.98 GW), while SBM is highly efficient in converting barotropic to baroclinic energy (4.1 GW).

The Integral Equation appears in different fields of science and engineering mathematics, for example image processing and the concept of electromagnetic. The technique of wavelet transform to find the solution of integral equations allows creating an algorithm after comparing with known algorithms. This paper is about the uses of the Dunkl Wavelet transforms and associated convolution to establish some suppositions for solution of these equations on distribution spaces. This work defined the method to solve various integral equations by using the Dunkl wavelet transforms.