Enhancement of magnetoresistance in manganite multilayers

Magnanite multilayers have been fabricated using La0.67Ca0.33MnO3 as the ferromagnetic layer and Pr0.7Ca0.3MnO3 and Nd0.5Ca0.5MnO3 as the spacer layers. All the multilayers were grown on LaAlO3 (100) by pulse laser deposition. An enhanced magnetoresistnace (defined (RH- R0)/R0) of more than 98% is observed in these multilayers. Also a low field magnetoresistance of 41% at 5000 Oe is observed in these multilayer films. The enhanced MR is attributed to the induced double exchange in the spacer layer, which is giving rise to more number of conducting carriers. This is compared by replacing the spacer layer with LaMnO3 where Mn exists only in 3+ state and no enhancement is observed in the La0.67Ca0.33MnO3 / LaMnO3 multilayers as double exchange mechanism can not be induced by external magnetic fields.Comment: 13 pages, 5 Figure

Engaging local communities in social learning for inclusive management of native fruit trees in the Central Western Ghats, India

Participatory research and the social learning it supports are increasingly being used to improve forest management. Yet, the participation of women and other marginalized groups is often limited in these processes. This is a serious shortcoming, not only due to concerns for gender and social equity, but also because socially excluded, forest-dependent groups hold specific ecological knowledge, skills and interests that influence prospects for sustainable forest management. Carried out in India’s Central Western Ghats, this study explores the potential participatory research holds for engaging communities in a socially inclusive learning process that can support forest management. Participatory tools – resource mapping, Four Cell Analysis, seasonal fruit calendar, and seasonal activity – were used to elicit information on native fruit tree diversity, phenology, agronomy, uses and marketing. We discuss the benefits of this research set-up which promoted interactions among individuals from different groups, who came to experience a common group identity. The notion of contact zones – where different cultures or groups meet and engage with each other in ways that can reduce conflicts or redress asymmetrical power relations – guides our analysis. We demonstrate that the contact zone created through research process facilitated multi-directional information sharing and supported collective actions for forest management

Estimation in Truncated Exponential Family of Distributions

Estimating the parameters of a truncated distribution is a well known problem in statistical inference. The non-existence of the maximum likelihood estimator (m.l.e.) with positive probability in certain truncated distributions is not well known. To mention a few results in the literature: (i) Deemer and Votaw 1955 show that the maximum likelihood estimator does not exist in a truncated negative exponential distribution on 0,T , T \u3e 0 known, whenever the sample mean x (GREATERTHEQ) T/2. (ii) Broeder 1955 shows that the maximum likelihood estimator of the scale parameter of a truncated gamma distribution, with the shape parameter being known, becomes infinite with positive probability whenever the sample mean x (GREATERTHEQ) α/α + 1, a \u3e 0. (iii) Mittal 1984 derives a sufficient condition for the non-existence of the maximum likelihood estimator in a two parameter doubly truncated normal distribution on A,B , A \u3c B known. The m.l.e.\u27s become infinite whenever the sample variance exceeds (B-A)2/12. (iv) Barndoff-Neilsen 1978 (BN) gives a set of general conditions for the existence and uniqueness of a solution to the maximum likelihood equations in a minimal representation of a k-parameter exponential family which depend upon a few results from convex analysis. Using certain results from BN 1978 , we give a unified approach to the problem of maximum likelihood estimation in the two parameter doubly truncated normal, truncated gamma, and singly truncated normal families, and obtain a set of necessary and sufficient conditions in terms of observable sample quantities. This approach basically depends upon characterizing the population and the sample moment spaces using a monotonicity property of the moments. We also study the Bayes modal estimator introduced by Blumenthal and Marcus 1975 and the harmonic mean estimator introduced by Joe and Reid 1984 . We present certain computational results for solving the maximum likelihood equations in the above families. Simulation results for the probability of non-existence of the m.l.e., for the bias vector, and for the mean square error of the Bayes modal, the harmonic mean and the mixed estimator are presented

Integrated management of pod rot disease of cocoa in hilly tracts of Karnataka

Cocoa suffers heavily due to pod rot disease caused by Phytophthora palmivora, causing yield losses ranging from 30 to 60 per cent. For devising strategies for effective management of pod rot disease, the present study was conducted during Kharif seasons of 2012-13 and 2013-14 in farmer’s field in the hilly tracts of Uttara Kannada district of Karnataka State, India. The results revealed that sequential spray of Metalaxyl MZ 68WP at 0.2 per cent followed by 1 per cent Pseudomonas fluorescens at 15 days interval significantly reduced the severity of pod rot disease (20.1%) in cocoa. This was followed by spraying of Mancozeb at 0.25 per cent + P. fluorescens at 1 per cent and spraying of Bordeaux mixture (1%) + P. fluorescens at 1 per cent. The reduction in disease severity has reflected in increased crop yield. The plots sprayed with Metalaxyl MZ 68WP + P. fluorescens has recorded the highest yield of 518.2 kg of dry beans ha-1 followed by 436.2 and 433.6 kg ha-1, respectively, in Mancozeb + P. fluorescens and Bordeaux mixture + P. fluorescens. The maximum disease severity was recorded in untreated control plots (46.2%) with a minimum yield of 337.3 kg ha-1. The highest net return of ` 62,007 was recorded in plots sprayed with Metalaxyl MZ 68WP + P. fluorescens sprayed plots. Thus, the integration of chemicals with a biological control agent was found to be promising not only in the management of pod rot disease but also in obtaining higher net returns in cocoa