The generalized gradient approximation kernel in time-dependent density functional theory

A complete understanding of a material requires both knowledge of the excited states as well as of the ground state. In particular, the low energy excitations are of utmost importance while studying the electronic, magnetic, dynamical, and thermodynamical properties of the material. Time-Dependent Density Functional Theory (TDDFT), within the linear regime, is a successful \textit{ab-initio} method to access the electronic charge and spin excitations. However, it requires an approximation to the exchange-correlation (XC) kernel which encapsulates the effect of electron-electron interactions in the many-body system. In this work we derive and implement the spin-polarized XC kernel for semi-local approximations such as the adiabatic Generalized Gradient Approximation (AGGA). This kernel has a quadratic dependence on the wavevector, {\bf q}, of the perturbation, however the impact of this on the electron energy loss spectra (EELS) is small. Although the GGA functional is good in predicting structural properties, it generality overestimates the exchange spin-splitting. This leads to higher magnon energies, as compared to both ALDA and experiment. In addition, interaction with the Stoner spin-flip continuum is enhanced by AGGA, which strongly suppresses the intensity of spin-waves.Comment: 11 pages, 7 figure

Effet de la salinité sur la croissance et la production de biomasse de deux provenances de Jatropha curcas L. cultivés en serre

La salinisation des sols est un processus important de dégradation des sols. Ce phénomène ne cesse de prendre de l’ampleur. Il affecte la croissance et le rendement des cultures. L’utilisation d’espèces à usages multiples telle que Jatropha curcas L. et capable de se développer dans ces milieux est d’une importance capitale. Cette étude a porté sur l’effet de différentes concentrations de NaCl (0 g/l, 2 g/l, 4 g/l, 8 g/l, 16 g/l et 35 g/l) pendant une durée de 42 jours sur des jeunes plants de deux provenances (Nioro et Kaffrine) de Jatropha curcas L en condition de serre vitrée. La tolérance des deux provenances par rapport aux différentes concentrations de NaCl a été étudiée en tenant compte des paramètres de croissance et de rendement. Les résultats ont montré que la hauteur des tiges, le diamètre au collet, la biomasse sèche des parties aériennes et des parties racinaires évalués à la fin de l’expérience varient en fonction du niveau du stress salin. Les deux provenances ont montré une tolérance à la salinité manifestée par la réduction d’un appareil aérien et racinaire important. La provenance Nioro présente une croissance des organes aériens plus importante que celle de Kaffrine. Cependant, la provenance Kaffrine produit plus de biomasse sèche aérienne. Cette différence se situe au niveau de la quantité de biomasse sèche apportée par les tiges.Mots clés : Stress salin, croissance, biomasse, Jatropha curcas L., provenance

Economic dynamics of tissue cultured strawberry (Fragaria× ananassa) under the influence of integrated plant nutrients in humid sub tropical hills of North Eastern India

Satisfactory and sustainable level of agricultural production can be achieved by combined application of inorganic fertilizers with organic manures, bio-fertilizers, bio-regulators and vermicompost. A field experiment was conducted during 2010-12 at experimental farm, Department of Horticulture, Aromatic and Medicinal Plants, Mizoram University, Aizawl, India, to find out the profitability of tissue cultured strawberry (Fragaria × ananassa Duch.) (cv. Festival) cultivation by using various integrated plant nutrient system (IPNS) combining inorganic fertilizers with organic manures, bio-fertilizers and bio-regulators. The response of IPNS on economics of strawberry indicated that the overall cost of cultivation as well as economics of strawberry production was significantly influenced by integration of various components. Among the different treatments, the highest expenditure of Rupees 2 077 576.83/ha was incurred in 100% RDF + vermicompost as against the lowest in control. With respect to the income, the highest net income of Rupees 7 298 119.27/ha was obtained in 75 % RDF + vermicompost + Azospirillum + PSB + 50 ppm GA3+50 ppm BA. The same treatment also recorded the highest cost benefit ratio of 1: 3.51

Economic analysis of tissue cultured banana (Musa × paradisiaca) production under the influence of integrated nutrient management

An experiment was conducted to evaluate various integrated nutrient management packages to evaluate the yield, quality and economics of banana (Musa × paradisaca L.) cultivation during 2008-2010. The response of INM on economics of tissue cultured banana cv. Grand Naine indicated that the overall cost of cultivation as well as economics of banana production was significantly influenced by integration of biofertilizers, organic manure and inorganic fertilizers. Among the different treatments, highest expenditure of ₹ 264 110.00 per ha was incurred in 100% RDF + VAM + Azospirillum + PSB + Trichoderma harzianum. However, the same treatment recorded the highest gross as well as net income. In spite of maximum cost of cultivation, the highest cost benefit ratio of 4.22:1 was also recorded in this treatment, followed by 75% RDF +VAM + Azospirillum + PSB + Trichoderma harzianum

Clues to multiple exposure history of some meteorites

This article does not have an abstract

Thawing Versus. Tracker Behaviour: Observational Evidence

Currently there is a variety of scalar field models to explain the late time acceleration of the Universe. This includes the standard canonical and non-canonical scalar field models together with recently proposed Galileon scalar field models. One can divide all these scalar field models into two broad categories, namely the thawing and the tracker class. In this work we investigate the evidence for these models with the presently available observational data using the Bayesian approach. We use the Generalized Chaplygin Gas (GCG) parametrization for dark energy equation of state (EoS) as it gives rise to both the thawing and tracking behaviours for different values of the parameters. Analysis of the observational data does not give any clear evidence for either thawing or tracking behaviour within the context of background cosmology, However, if we consider the evolution of inhomogenities and analyze the data in this context then there is a significant evidence in favour of thawing behaviour.Comment: 6 Pages, three eps figures, new material added, new references added. Conclusion changed. Accepted for publication MNRA

Deviation From \Lambda CDM With Cosmic Strings Networks

In this work, we consider a network of cosmic strings to explain possible deviation from \Lambda CDM behaviour. We use different observational data to constrain the model and show that a small but non zero contribution from the string network is allowed by the observational data which can result in a reasonable departure from \Lambda CDM evolution. But by calculating the Bayesian Evidence, we show that the present data still strongly favour the concordance \Lambda CDM model irrespective of the choice of the prior.Comment: 15 Pages, Latex Style, 4 eps figures, Revised Version, Accepted for publication in European Physical Journal

Perceptions of change in the environment caused by the COVID-19 pandemic: implications for environmental policy

COVID-19 lockdown measures have impacted the environment with both positive and negative effects. However, how human populations have perceived such changes in the natural environment and how they may have changed their daily habits have not been yet thoroughly evaluated. The objectives of this work were to investigate (1) the social perception of the environmental changes produced by the COVID-19 pandemic lockdown and the derived change in habits in relation to i) waste management, energy saving, and sustainable consumption, ii) mobility, iii) social inequalities, iv) generation of noise, v) utilization of natural spaces, and, vi) human population perception towards the future, and (2) the associations of these potential new habits with various socio-demographic variables. First, a SWOT analysis identified strengths (S), weaknesses (W), opportunities (O), and threats (T) generated by the pandemic lockdown measures. Second, a survey based on the aspects of the SWOT was administered among 2370 adults from 37 countries during the period from February to September 2021. We found that the short-term positive impacts on the natural environment were generally well recognized. In contrast, longer-term negative effects arise, but they were often not reported by the survey participants, such as greater production of plastic waste derived from health safety measures, and the increase in e-commerce use, which can displace small storefront businesses. We were able to capture a mismatch between perceptions and the reported data related to visits to natural areas, and generation of waste. We found that age and country of residence were major contributors in shaping the survey participants ´answers, which highlights the importance of government management strategies to address current and future environmental problems. Enhanced positive perceptions of the environment and ecosystems, combined with the understanding that livelihood sustainability, needs to be prioritized and would reinforce environmental protection policies to create greener cities. Moreover, new sustainable jobs in combination with more sustainable human habits represent an opportunity to reinforce environmental policy

Bacterial Distribution in the Rhizosphere of Wild Barley under Contrasting Microclimates

Background: All plants in nature harbor a diverse community of rhizosphere bacteria which can affect the plant growth. Our samples are isolated from the rhizosphere of wild barley Hordeum spontaneum at the Evolution Canyon (‘EC’), Israel. The bacteria which have been living in close relationship with the plant root under the stressful conditions over millennia are likely to have developed strategies to alleviate plant stress. Methodology/Principal Findings: We studied distribution of culturable bacteria in the rhizosphere of H. spontaneum and characterized the bacterial 1-aminocyclopropane-1-carboxylate deaminase (ACCd) production, biofilm production, phosphorus solubilization and halophilic behavior. We have shown that the H. spontaneum rhizosphere at the stressful South Facing Slope (SFS) harbors significantly higher population of ACCd producing biofilm forming phosphorus solubilizing osmotic stress tolerant bacteria. Conclusions/Significance: The long-lived natural laboratory ‘EC ’ facilitates the generation of theoretical testable and predictable models of biodiversity and genome evolution on the area of plant microbe interactions. It is likely that the bacteria isolated at the stressful SFS offer new opportunities for the biotechnological applications in our agro-ecologica