Reply to Comment on ``Two-dimensional charged-exciton complexes''

We respond to criticisms raised by K. Varga (cond-mat/9802262) and reaffirm that the results in our original paper obtained using a two-body analytical method remains valid within the framework of an effective excitonic composite model. The conceptual model of the excitonic systems as well as the numerical method based on variational functions utilized by Varga differ significantly from ours. Hence comparison of binding energies of the charged-biexciton remains questionable. In this reply, we discuss the shortcomings of modelling the charged-biexciton as a five-body system and treating excitonic complexes as atomic systems, as done in Varga's Comment.Comment: 3 pages, no figure

Theory of neutral and charged exciton scattering with electrons in semiconductor quantum wells

Electron scattering on both neutral ($X$) and charged ($X^-$) excitons in quantum wells is studied theoretically. A microscopic model is presented, taking into account both elastic and dissociating scattering. The model is based on calculating the exciton-electron direct and exchange interaction matrix elements, from which we derive the exciton scattering rates. We find that for an electron density of $10^9 {\rm cm}^{-2}$ in a GaAs QW at $T=5K$, the $X^-$ linewidth due to electron scattering is roughly twice as large as that of the neutral exciton. This reflects both the $X^-$ larger interaction matrix elements compared with those of $X$, and their different dependence on the transferred momentum. Calculated reflection spectra can then be obtained by considering the three electronic excitations of the system, namely, the heavy-hole and light-hole 1S neutral excitons, and the heavy-hole 1S charged exciton, with the appropriate oscillator strengths.Comment: 18 pages, 12 figure

Marriage Customs of Kongu Vellalar's

The Kongu Vellalar were of great assistance to the king by being in various positions and ranks in the army. They also got the title ‘Kamindan' from the ding for their meritorious service and loyalty. Late the title got modified as Counden'. Certain rules and procedures were put in place to help the boy and girl live together more smoothly. Certain rules' processes and customs evolved into 'rites.' Marriage is the combined execution of all ceremonies in a sequence termed marriage. All ceremonies linked with KonguVellalar marriage are done by 'arumaikaarar' arumaikaari, naavidhan (Barbar), washing man (vannaan), and others intimately associated with the occupation of KonguVellalaGounders. The KonguVellalar marriage is similar to the Aryan 'prajaapathyam' type marriage. In a KonguVellalar marriage, the bridegroom's family visits the bride's home to propose the marriage and seek the bride's family's approval for the match. The marriage takes happens once the bride's family gives their assent

Exploring Hydroponics and the Associated Technologies for Use in Medium-and Small-scale Operations: A Review

Hydroponics, the science of soilless agriculture, has emerged as a pivotal paradigm in modern cultivation practices, addressing myriad challenges of traditional farming and offering avenues for high-efficiency, sustainable food production. This review delves into the anticipated future directions of hydroponics, capturing its interdisciplinary evolution. Central to this trajectory is the integration of Artificial Intelligence (AI) and machine learning, aiming to augment precision in every facet of hydroponic cultivation, from nutrient balance to disease prediction. Complementing technological advancements is the burgeoning realm of genomics, poised to craft crop varieties intrinsically optimized for hydroponic conditions, promising both enhanced yields and improved nutritional profiles. Sustainability remains an unwavering focus, with innovative methodologies underscoring recycling and resource optimization, ensuring minimal waste and maximal output. The synergistic amalgamation of hydroponics with other agricultural models, notably aquaponics, paints a picture of integrated, multi-tiered ecosystems that not only boost productivity but also bolster ecological resilience. Such integrations herald a future where farming transcends singular methodologies, evolving into harmonized systems that capitalize on the strengths of individual disciplines. In essence, the horizon of hydroponics is not one of mere technical advancement but represents a holistic evolution, seamlessly melding technology, biology, and ecology. This review aims to provide a comprehensive overview of these trajectories, offering insights into the potentialities and promises that the future of hydroponics holds

Sustainable Water Harvesting for Improving Food Security and Livelihoods of Smallholders under Different Climatic Conditions of India

In India, the per capita availability of water is projected to be 1465 m3 and 1235 m3 by the years 2025 and 2050, respectively, and hence, India would be a water-stressed country as per the United Nations’ standard of less than 1700 m3 per capita water availability. India is predominantly an agricultural-dominant country. Rainfed agriculture in the country contributes 40% of food grain production and supports half of the human population and two-thirds of the livestock population. The country has 15 different agro-climatic zones, and each agro-climatic region has its own constraints of water availability and management along with the potential for their optimum utilization. Such situations warrant the formulation of regional-level strategies. Efforts were made to integrate and evaluate the feasibility of water harvesting and its utilization at twelve different sites representing six different agro-climatic conditions spanning pan India. It was found that water harvesting through tanks/ponds is a feasible approach and can increase the crop production as well as diversification. The results reveal that the range of crop diversification index increased from 0.49–0.85 to 0.65–0.98; the crop productivity index increased from 0.28–0.66 to 0.66–0.90; the cultivated land utilization index increased from 0.05–0.69 to 0.34–0.84; and the crop water productivity index increased from 0.20–0.51 to 0.56–0.96, among other production and diversification indices, due to additional water availability through rainwater harvesting intervention. Moreover, the gross return increased from INR 43,768–704,356 to INR 220,840–1,469,108 ha−1, representing a 108 to 400% increase in the returns due to the availability of water. The findings of this study suggest that the water harvesting in small ponds/tanks is economical and feasible, requires less technological intervention, and increases crop diversification in all the studied agro-climatic conditions, and hence, the same needs to be encouraged in the rainfed areas of the country