Free Deterministic Equivalents for the Analysis of MIMO Multiple Access Channel

In this paper, a free deterministic equivalent is proposed for the capacity analysis of the multi-input multi-output (MIMO) multiple access channel (MAC) with a more general channel model compared to previous works. Specifically, a MIMO MAC with one base station (BS) equipped with several distributed antenna sets is considered. Each link between a user and a BS antenna set forms a jointly correlated Rician fading channel. The analysis is based on operator-valued free probability theory, which broadens the range of applicability of free probability techniques tremendously. By replacing independent Gaussian random matrices with operator-valued random variables satisfying certain operator-valued freeness relations, the free deterministic equivalent of the considered channel Gram matrix is obtained. The Shannon transform of the free deterministic equivalent is derived, which provides an approximate expression for the ergodic input-output mutual information of the channel. The sum-rate capacity achieving input covariance matrices are also derived based on the approximate ergodic input-output mutual information. The free deterministic equivalent results are easy to compute, and simulation results show that these approximations are numerically accurate and computationally efficient.Comment: 26 pages, 7 figures, Accepted by IEEE Transactions on Information Theor

Current algebra based effective chiral theory of mesons and a new EW theory

A current algebra based effective chiral theory of pseudoscalar, vector, axial-vector mesons is reviewed. A new mechanism generating the masses and guage fixing terms of gauge boson is revealed from this effective theory. A EW theory without Higgs is proposed. The masses and gauge fixing terms of W and Z are dynamically generated. Three heavy scalar fields are dynamically generated too. They are ghosts.Comment: 4 pages, talk presented at conference of QCD and hadronic physics, 6/16-6/21, Beijing, Chin

Effect of dissipative forces on the theory of a single-atom microlaser

We describe a one-atom microlaser involving Poissonian input of atoms with a fixed flight time through an optical resonator. The influence of the cavity reservoir during the interactions of successive individual atoms with the cavity field is included in the analysis. The atomic decay is also considered as it is nonnegligible in the optical regime. During the random intervals of absence of any atom in the cavity, the field evolves under its own dynamics. We discuss the steady-state characteristics of the cavity field. Away from laser threshold, the field can be nonclassical in nature.Comment: 9 pages in LaTex; 3 PS figure

Animal health of ruminants: A summary of research conducted under the German Federal Programme for Organic Agriculture and other forms of Sustainable Agriculture

Between 2002 and 2003, a survey established the status quo of organic dairy and beef production. A questionnaire was sent to 750 farms, supplemented by an on-site survey of 100 farms that supplied data on livestock performance, profitability, feeding, animal health and housing conditions. In a num-ber of the 74 dairy farms investigated, deficiencies regarding animal welfare were found, because recommendations for disease prevention had been implemented poorly. In the production of suckler cows only a few problems were identified; the main obstacle to further development of organic cattle rearing was considered to be the low prices paid to producers. A further study looked at what preventive measures against the major disease groups of mastitis, lameness, metabolic disorders were used in organic dairy farming, collected data on the actual animal health situation and developed preventive animal health concepts that were made available to advisory services. In the same period, a study of the effect of homeopathic remedies for mastitis in dairy cows showed that the use of dry-cow antibiotics can be reduced, but their use cannot be fully eliminated in problem cases. Another status analysis from 2003 to 2004 focused on the state of knowledge on issues such as mastitis, fertility, metabolism and claw disorders in dairy cows and selected diseases in pigs and poultry. The surveys showed that the health status of animals in the organic livestock was not signifi-cantly different from that in conventional animal production and that there was a relatively high inci-dence rate, regardless of the production method. Between 2004 and 2005, a vulnerability assess-ment of the acute need for improvement focusing on small ruminants was carried out, leading to various recommendations. In 2007, building on the previous results, a large, interdisciplinary collaborative project on the health and performance of dairy cows was set up. At the same time the CORE Organic project on health planning for dairy cows (ANIPLAN) was running (also in the UK). The German subproject included the aims to develop animal-health-and-welfare plans (AHW plans) for organic dairy farming, the monitoring of health and welfare of dairy cattle, and the development of advisory tools, including the initiation of regional ‘stable schools’ as an innovative means of communication on the subject of animal health and animal welfare. A further project on stable schools is still ongoing. In 2009, a project was initiated to assist farmers in grazing management with the help of a web-based decision-tree tool. The aim of another ongoing project is to improve udder health in dairy goats by identifying appropriate indicators for the early detection of subclinical mastitis. Further results from the BÖLN research on animal health in ruminants are continuously published at www.bundesprogramm-oekolandbau.de

Plant protection in organic arable and horticultural production: A summary of research conducted under the German Federal Programme for Organic Agriculture and other forms of Sustainable Agriculture

Plant protection in arable and horticultural production was one of the central topics for research in the Federal Programme for Organic Agriculture. Since 2002, 53 projects have been carried out on this subject. After several status quo analyses (2002-2004), methods for control and prevention of pests and diseases were further developed and adapted to organic farming conditions. Focus areas included copper replacement, resistant varieties and improved cultivation methods. Plant health issues were also addressed in various speciality crops where pests and diseases often lead to the need to import produce from other European countries (e.g. Brussels sprouts), as domestic production cannot cover the ever-increasing demand; in this area, several projects were set up to improve growing conditions and establish new methods for plant protection. One important focus was the control of downy mildew, particularly in organic onion cultivation. In this case insights from conventional farming were adapted to organic farming conditions, e.g. in the control of downy mildew in summer onion cultivation. The growing risk of the occurrence of downy mildew in organic onion cultivation could be further reduced through the use of new, mildew-resistant varieties. New alternatives to the use of copper, such as plant extracts of sage and liquorice or microbial preparations with Aneurinibacillus migulanus demonstrated a significant reduction of infestation in onion and cucumber. In organic potatoes, primary stem infection by late blight (Phytophthora infestans) was significantly reduced by seed dressing using small amounts of copper (120 g/ha, compared to higher amounts that would be needed for a foliar treatments in the field); this led to yields increases by up to 55%. Alternative pesticides were tested against the pea moth (Cydia nigricana); here, a pyrethroid formulation showed variable effects and Spruzit-Neu® was unable to reduce pest infestation at high insect densities. The use of beneficial insects and other cultural methods was extensively studied. Covering Brussels sprouts with fine-meshed nets from the time of transplanting until the end of October achieved a 77% reduction in the infestation with cabbage whitefly (Aleyrodes proletella) during the main infestation period in September. In field trials with point releases of the parasitic wasp Encarsia tricolor, parasitism was up to 50% higher than in the reference without release; bringing the first release forward in time resulted in a significant pest reduction by about 60%. Studies on the control of carrot fly (Chamaepsila rosae) showed that a major risk factor for infestation is the distance to fields where carrot had been grown in the previous year, and thus field selection offers a major control option. In addition, the research showed that infestation can be limited by growing either early or late sets of carrots. Another project dealt with the natural control of the grain weevil (Sitophilus granarius) by a continuous release of the ectoparasitoid Lariophagus distinguendus in grain stores. This method is intended to be an affordable, easy-to-use and effective alternative to existing release methods. Further results from the BÖLN research on pest management in Crop Production are regularly published at www.bundesprogramm-oekolandbau.de

Food quality: A summary of research conducted under the German Federal Programme for Organic Agriculture and other forms of Sustainable Agriculture

Food quality has been a strong focus of the BÖL research programme since it started in 2001. Among other things, the policy on EU organic regulations was supported with research projects; for example regarding the discussion concerning the admission of meat curing agents (nitrite and nitrate) in 2006. In a project on this subject, consumer acceptance of cured meat products, not using these curing agents, has been described as surprisingly positive, and the practical use of alternative materials and technologies was evaluated. It was found that the implementation of new technologies to reduce the use of curing agents was mainly inhibited by their lacking acceptance in practice, technical adaptation needs and investment in product development as well as disputed legal issues. As part of another project, a guide for processors was created, within which the new methods and solutions were presented. To enhance knowledge transfer regarding the new EU hygiene standards for organic meat proces-sors in 2008, a number of general information and specific documents for the admission application as well as templates for the necessary internal controls were developed. The general use and suitability of new organic food additives were also examined. Different sub-stances, which could serve as binding agents or antioxidants, were tested. Locust bean gum, guar gum, xanthan and agar agar showed a sufficient bond-stabilising effect without affecting the sensory quality of the products. Substances such as ascorbic acid, citric acid, rosemary extract, ginger and lemon juice showed a satisfactory effect against oxidative browning reactions. Furthermore, the use of rye sprouts as an ingredient in wheat bread produced very positive results: a study found that the volume, crumb firmness and crumb elasticity could be improved. The use of ingredients from yam (Dioscorea batatas) was investigated regarding the potential sensory and health benefits for flour blends. In another project, the use of yeast extract in organic foods was reviewed. It was shown here that there is very little research about the components and nutritional effects of yeast extract; also a survey among experts could not come to a clear formulation of conclusions. Thus, it was recommended that each processor should decide for or against the use of yeast extract in each particular case. Since 2008, an additive list is now being published annually and a website has been created where the manufacturers of additives can register themselves and sign up their organically certified and non-certified commercial products for evaluation. The data from the National Nutrition Survey II (NVS II) in 2010 were analysed in detail, looking at organic buying habits in relation to socio-demographic characteristics, parameters of health and nutrition behaviour as well as food consumption. Over 13,000 participants, aged between 18 and 80 years, were included in this survey. The derived recommendations show considerable potential. It was found for example, that organic buyers compared with non-organic buyers are more likely to lead a healthier lifestyle. Altruistic buying motives, such as interest in fair trade, animal welfare and the renunciation of the use of genetic modification, have been identified as a central driver of organic buying behaviour. It was also recommended, in addition to ethical arguments, to integrate health benefits more directly into the marketing of organic food. Further results from the BÖLN research on food quality and processing are continuously published at www.bundesprogramm-oekolandbau.de