Exploring the organic agriculture practice in Mexico: an opportunity for small-scale farmers to feed themselves

We examine how organic farming practiced by small farmers in rural zones in Mexico could build a self-sufficient food system. We hold the hypothesis that the promotion of the local consumption of organic produce is an alternative to strengthen the local economy needed to sustain food self-sufficiency. The hypothesis stands against export oriented market and high external input technology of industrial agriculture that erodes small-scale farmers’ ability for self-sufficient food. Firstly, a debate about how organic farming systems promote local economies is presented, drawing on sustainable agriculture approach. Organic agriculture seems to be a suitable alternative for small-scale farmers because it allegedly diminishes financial vulnerabilities since they drop chemicals and external scientific assistance costs. Secondly, by analyzing some interviews to consumers in Mexico City, and documentary sources, we characterize the socio-economic networks supporting the organic practice in the country. Finally, we trace perspectives and conclusions of this alternative.organic agriculture, self-sufficient food system, local food system, direct marketing, Mexico., Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

Contributions to the sociology of law : a critical reading of Marx and Weber : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Sociology, Massey University

The purpose of this thesis is to aid the process of uderstanding the sociology of law - what it has been and what it can be. It is most important to consider to what extent can law and sociology contribute in the real human struggle for economic, social and political freedom. There are points of convergence and important differences between the legal and the sociological approaches to the study of law and society. Today, interdisciplinary research is increasing at different levels of law and sociology, and a new analytical perspective, a contemporary sociology of law, has emerged. In order to point out new directions within this field of enquiry, we try to grasp the differences and interstices between the approaches made by law and sociology. Both perspectives are important in the analysis of the dual nature of law, that is, as a product of society and as a system making itself felt in society. Our concern in this thesis is with law as a social phenomenon from a sociological perspective, and in particular, with the contribution of Marx and Weber to an understanding of the relationship between law and society. The most important aspects of Marx's and Weber's contributions to the sociology of law have to do with philosophical and epistemological considerations. What Weber and Marx thought about human nature and how they conceived science is still fundamental to contemporary developments in the sociology of law. The critical discussion of Marx' and Weber's work attempts to show how partially conflicting and yet complementary sociological perspectives can contribute to a theoretical and conceptual convergence of sociological and legal approaches to the analysis of law and society. Traditionally Weber and Marx have been seen as belonging to two totally opposed philosophical positions. However, we explore here premises which they share, in the hope of opening a new dialogue between their legacies. The approach made here is tentative and certainly incomplete. There are no conclusive remarks which force a particular synthesis upon otherwise 'incommensurate' positions

Cross-coupled doa trackers

A new robust, low complexity algorithm for multiuser tracking is proposed, modifying the two-stage parallel architecture of the estimate-maximize (EM) algorithm. The algorithm copes with spatially colored noise, large differences in source powers, multipath, and crossing trajectories. Following a discussion on stability, the simulations demonstrate an asymptotic and tracking behavior that neither the EM nor a nonparallelized tracker can emulate.Peer ReviewedPostprint (published version

Rheological behaviour of fruit and milk-based smoothies

Two of the most important food attributes for today´s fast-moving lifestyle are convenience and healthiness [1-2]. Fast-moving lifestyle specifically affects to elderly people, who are prone to bad-nutrition due to their dental status reducing the consumption of fruits and vegetables [3]. Smoothies are blended beverages, and good examples of convenient and healthy foods for helping to reduce this problem. So, they are gaining increasing market leverage in the beverage sector. Texture and rheological behaviour of foods can determine their acceptability. Therefore, added to nutritious features, smoothies must also account with outstanding mechanical properties. Stability of the products is also a main quality, which can be gained adding a small amount of stabiliser to beverage formulations. But, to avoid opposite effects, stabilisers addition should ameliorate the product texture.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Predictive potential of genotypes within the prolactin, growth hormone and insulin -like growth factor-I pathways in genetic evaluation of 305 days milk yield in Holstein cows in Sonora, Mexico

Includes bibliographical references.2015 Summer.The objective of this study was to calculate a molecular breeding value (MBV) using single nucleotide polymorphims (SNP) within genes of the prolactin (PRL) and growth hormone and insulin-like growth factor (GH-IGF1) pathways associated with milk production traits and evaluate their effectiveness in genetic prediction in Holstein cows in Sonora, Mexico. We hypothesized that MBV constructed using DNA markers within the PRL and GH-IGF1 pathways have the potential to predict milk production traits in heat-stressed lactating Holstein cows. The data contained observations of 659 Holstein dairy cows collected during 2012 from the city of Obregón, Sonora, Mexico. Milk yield observations were recorded monthly and 305 d milk yield was calculated. Cows were genotyped for 179 tag SNP within 43 genes in the PRL and GH-IGF1 pathways. Eight SNP within 5 genes were associated with 305d milk yield (P ≤ 0.05). No previous research reported these associations. Their effects were used to estimate a MBV. The linear correlation of the MBV and 305 d milk yield was 0.21 and the adjusted R² was 4.5%. Genetic parameters were estimated in ASREML for 305 d milk yield (h² = 0.39 ± 0.11). A training and predicting exercise, was performed using SAS 9.4 with the same data set. The SNP effects and association were estimated and used to calculate an MBV. The MBV was estimated and evaluated by comparing estimates from a 5-fold strategy of random clustering. This procedure was repeated five times, resulting in five MBV. To evaluate the effectiveness of these MBV, correlations and adjusted R² were estimated between MBV and 305 d milk yield. One MBV (MBV5) was correlated (-0.27) and had an adjusted R² of 6.37%. The MBV estimated from SNP within the PRL and GH-IGF1 pathways genes was positive but weakly associated with 305 d milk yield. In the training-predicting exercise, only 1 of the 5 MBV explained a portion of the variation in 305 d milk yield. The small amount of phenotypic variation may be due to the small numbers of SNP used to calculate the MBV and the polygenic nature of the trait under heat stress conditions. The quality of the data, could also affect the results. We accept our hypothesis, the MBV was capable of predicting a portion of the phenotypic variation in 305 d milk yield in lactating Holstein cows in Sonora, MX. Nevertheless, the accuracy and amount of variability explained was not enough to be feasible for use in genetic selection procedures

Phase only transmit beamforming for spectrum sharing microwave systems

This paper deals with the problem of phase-only transmit beamforming in spectrum sharing microwave systems. In contrast to sub-6 GHz schemes, general microwave systems require a large number of antennas due to its huge path loss. As a consequence, digital beamforming needs a large number of computational resources compared to analog beamforming, which only needs a single radio-frequency chain, results the less computational demanding solution. Analog schemes are usually composed by a phase shifter network whose elements transmit at a certain fixed power so that the system designer shall compute the phase values for each element given a set of directions. This approach leads to non-convex quadratic problems where the traditional semidefinite relaxation fails to deliver satisfactory outcomes. In order to solve this, we propose a nonsmooth method that behaves well in several scenarios. Numerical evaluations in different spectrum sharing scenarios, which show the performance of our method, are provided.Peer ReviewedPostprint (author's final draft

The X-ray variability of Seyfert 1.8/1.9 galaxies

Seyfert 1.8/1.9 are sources showing weak broad H-alpha components in their optical spectra. We aim at testing whether Seyfert 1.8/1.9 have similar properties at UV and X-ray wavelengths to Seyfert 2. We use the 15 Seyfert 1.8/1.9 in the Veron Cetty and Veron catalogue with public data available from the Chandra and/or XMM-Newton archives at different dates, with timescales between observations ranging from days to years. Our results are homogeneously compared with a previous work using the same methodology applied to a sample of Seyfert 2 (Hernandez-Garcia et al. 2015). X-ray variability is found in all 15 nuclei over the aforementioned ranges of timescales. The main variability pattern is related to intrinsic changes in the sources, which are observed in ten nuclei. Changes in the column density are also frequent, as they are observed in six nuclei, and variations at soft energies, possibly related to scattered nuclear emission, are detected in six sources. X-ray intraday variations are detected in six out of the eight studied sources. Variations at UV frequencies are detected in seven out of nine sources. A comparison between the samples of Seyfert 1.8/1.9 and 2 shows that, even if the main variability pattern is due to intrinsic changes of the sources in the two families, these nuclei exhibit different variability properties in the UV and X-ray domains. In particular, variations in the broad X-ray band on short time-scales (days/weeks), and variations in the soft X-rays and UV on long time-scales (months/years) are detected in Seyfert 1.8/1.9 but not in Seyfert 2. Overall, we suggest that optically classified Seyfert 1.8/1.9 should be kept separated from Seyfert 2 galaxies in UV/X-ray studies of the obscured AGN population because their intrinsic properties might be different.Comment: Accepted for publication in A&A. arXiv admin note: text overlap with arXiv:1505.0116

Activation energy in particle suspensions

Assuming that the molar activation energy in a fluid is interpreted as a measure of the potential energy barrier required for the molecular movement [1], the viscosity of a fluid depends on the actual size of the molecules, and the presence of solid particles in a suspension increases the dissipation of energy when the system flows, therefore it is expected that the viscosity of the suspension is higher than that of the pure solvent at a given temperature. The dependence of the viscosity of some silica/glycol suspensions with the temperature can be fitted using an empirical function analogous to the Arrhenius equation, ln⁡η=E/RT-ln⁡C, where η is the viscosity, C is a system-dependent constant, E is the molar activation energy for the viscous flow, T is the absolute temperature and R is the gas universal constant. When the temperature of the suspension decreases two effects are observed. First, larger aggregates of particles are formed due to the reduction of the thermal agitation and, second, the number of links among the molecules of the liquid phase increases. These two effects give place to a higher increase in the viscosity with the temperature compared to the pure solvent. Assuming that a higher viscosity value is due to a smaller free volume available for the molecular movement, and taking into account that the free suspension volume is limited only to the liquid fraction [2], it should be expected that the viscosity of the suspension is less sensitive to temperature than that of the pure solvent. In this work the dependence on the temperature of the viscosity values of the silica/glycol suspensions is compared to that of the liquid media. The results have shown a lower activation energy when the solid volume fraction increases, which has been explained with a scheme that assumes that the particle links are less sensitive to thermal energy absorption than the joining bonds among the solvent molecules. Our conclusion is that, for a given mechanical energy applied to the system, the thermal energy absorbed by the system is mainly used in the rupture of bonds between the solvent molecules. This study can be useful to understand the mechanisms that govern the differences in the activation energy values found between samples of foods, in which many factors are connected with sample composition [3]. [1] Briscoe B, Luckham P, Zhu S. Rheological properties of poly (ethylene oxide) aqueous solutions. J Appl Polym Sci 70 (1998) 419-429. [2] Shenoy AV. Rheology of filled polymer systems. Kluwer Acad Pub, 1999, The Netherlands. [3] Alvarez MD, Canet W. Time-independent and time-dependent rheological characterization of vegetable-based infant purees. J Food Eng 114 (2013) 449-464.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech