User Cooperation in TDMA Wireless System

Abstract: Reliability of radio link is limited, owing to path loss, shadowing and multi-path fading. This necessitates the use of a certain type of diversity. In recent years, cooperative diversity has gained considerable attention. Here, wireless nodes cooperate in such a way that they share their antennas and other resources, to create a virtual array through distributed transmission and signal processing. This increases coverage and reduces transmitted power, thereby bringing down co-channel interference, which results in increased system capacity. This paper gives an overview of the state of art of various cooperation schemes and issues related to their implementation

Theoretical Investigation of Different Diversity Combining Techniques in Cognitive Radio, Journal of Telecommunications and Information Technology, 2018, nr 3

In this paper, the performance of an energy detector in cognitive radio, using different diversity combining techniques, is evaluated. Among many diversity combining techniques, maximal ratio combining (MRC) gives the best results but at the cost of the highest complexity. To design a simpler receiver, it is suggested to use less complex combining techniques, i.e. switched diversity, which provides one of the least complex solutions to combat fading. The paper analyzes two switched diversity schemes, switch examine combining (SEC), and switch examine combining with post examining selection (SECp). A closed form expression determining the probability of detection using MRC, SEC and SECp is derived for various numbers of branches. Detection performance with different diversity combining techniques is compared and the complexity trade-off is observed

Antagonistic Compounds Producing Plant Growth Promoting Rhizobacteria: A Tool for Management of Plant Disease

Agriculture is facing struggle to meet the various confront of reducing plant diseases for an increasing world population food security. Great quantities of synthetic fertilizers and pesticides are required for high productivity which can damage ecosystem structures and functions, including the soil microbial community which plays an important role in agriculture sustainability. Soil is an excellent niche of growth of much plant growth promoting rhizobacteria. PGPR are naturally occurring soil bacteria that aggressively colonize in plant roots and play a vital role in crop protection, growth promotion and in the improvement of soil health. Scientific researchers involve multidisciplinary approaches to understand adaptation of PGPR, effects on plant physiology and growth induced systemic resistance, biocontrol of plant pathogens and biofertilization. The primary mechanism of biocontrol by PGPR involves the production of antibiotics such as carboxylic acid, 2,4-diacetyl phloroglucinoloomycin,pyoluteorin,pyrrolnitrin,kanosamine,zwittemycin-A and pantocin. A cascade of endogenous signals such as sensor kinases, N-acyl homoserine lactones and sigma factors regulates the synthesis of antibiotics. Some of these antibiotics have broad spectrum against many plant pathogens like fungi, viruses and bacteria, affecting crop plants. These antibiotics also serve as determinants in triggering induced systemic resistance (ISR) in the plant system

Experimentation in biology of plant abiotic stress responses

During the course of growth under natural field conditions, crop plants are exposed to a number of different abiotic stresses (such as water stress, temperature stress, salt stress, flooding stress, chemical stress and oxidative stress). These stresses exert adverse effects on metabolism, growth and yield of the crops. The intensity of the abiotic stresses is on the rise, implying that various possible solutions for mitigating the damage caused by such stresses must be combined for future increase in crop production. At the level of plant genetics, there are indications that it may be possible to improve plants against such stress factors. However, the practical success in this regard depends on how well we understand the biochemistry. physiology and molecular biology of the plant abiotic stress responses. The cellular response of plants to abiotic stresses is of complex nature involving simultaneous interplay of several mechanisms. Although there is a great deal of progress in cataloguing the biochemical reactions that are associated with plant abiotic stress responses, precise understanding of the defense reactions leading to acquisition of stress tolerance remains a challenge. A number of different experimental systems including lower and higher plants as well as microbes have been analyzed for examining the plant abiotic stress responses. The molecular analysis of the stress response has been carried out at the level of stress proteins, stress genes, stress promoters, trans-acting factors that bind to stress promoters and signal transduction components involved in mediation of stress responses. The functional relevance of the stress - associated genes is being tested in different trans-systems including yeast as well as higher plant species. In this article, we discuss selective features of experimentation in biology of plant abiotic stress responses

Engineering crops for tolerance against abiotic stress through gene manipulation

Plant genetic engineering took birth in the mid-eighties when, for the first time, plants were successfully engineered for improved virus, herbicide and insect resistance. This sphere has been ever-increasing since then. Abiotic stresses (such as high salt levels, low water availability leading to drought, excess water leading to flooding, high and low temperature regimes, etc.) adversely affect crop plants. The genetic responses of plants to these stresses are complex involving simultaneous expression of a number of genes. Till the early-nineties it was inconceivable that there would be any success in attaining the goal of improving resistance of crop plants to abiotic stresses. Continuing efforts of the stress biologists have resulted in engineering of plants resistant to low temperature, high temperature and excess salinity. A satisfactory progress has also been achieved in the area of generating plants resistant to water stress and flooding. While what has been achieved is impressive, it is still a challenging task to pyramid useful genes for high-level resistance to such stresses. The limiting factor in extension of biotechnology to abiotic stresses is the lack of information on what are the 'useful genes'-genes which would lead to better stress tolerance. We have reviewed how these genes are being searched to enable further development of strategies for stress management in crop plants. This is important because the strategics for coping with the abiotic stresses (and also for several other applications in plant biotechnology) have also come through the research work of scientists working on as diverse organisms as bacteria and fish

Knee Osteoarthritis in Women: Ancient and Modern Treatment Modalities

Knee osteoarthritis (OA) is a common and debilitating condition that predominantly affects women. This article explores the historical and contemporary treatment modalities for knee OA in women, highlighting the evolution of therapeutic approaches over time. Ancient treatments for knee OA primarily focused on natural remedies and lifestyle modifications. These included the use of herbal medicines, dietary adjustments, and physical therapies like hot and cold compresses. Ancient cultures recognized the importance of maintaining a healthy weight and engaging in physical activity to alleviate symptoms and improve joint function. In modern times, treatment options for knee OA in women have significantly evolved. While conservative measures such as physical therapy, weight management, and non-steroidal anti-inflammatory drugs (NSAIDs) are still important, advanced interventions are available. These include corticosteroid injections, hyaluronic acid injections, and platelet-rich plasma therapy, which aim to reduce pain and enhance joint lubrication. For severe cases, surgical interventions like arthroscopy, partial or total knee replacement, and osteotomy may be considered. The article also explores the emerging field of regenerative medicine, which offers promising avenues for the management of knee OA in women. Stem cell therapies and tissue engineering approaches show potential in regenerating damaged cartilage and slowing down disease progression. Additionally, the role of lifestyle modifications, exercise, and physical therapy remains crucial in the modern era, with a focus on tailored rehabilitation programs to improve strength, flexibility, and joint stability. In conclusion, the treatment of knee OA in women has transitioned from ancient remedies rooted in tradition to a modern, evidence-based approach that combines conservative measures with innovative medical interventions. The evolution of treatment modalities reflects advances in medical knowledge and technology, offering hope for improved quality of life for women affected by this condition