Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

This paper studies the technical efficiency in family farming, using as case of study the production of goat milk at the basin of Santiago del Estero, and using DEA and SFA. Regarding the efficiency of the studied farmers, it is observed that goat milk basin of Santiago del Estero has technical efficiency average indices of 0.567 (using DEA CRS), 0.693 (using DEA VRS) and 0.745 (using SFA). By comparing the results it shows that there are no differences in outcomes between DEA (VRS) and SFA, however differences are observed comparing the results of DEA (CRS) and SFA. In this context, no grounds were found to use either method for efficiency studies on family farming. The decision regards of which method to use should be taken considering each particular case, according to the type of information available, the formation of each research and the purpose of each particular study.

The design of a Horn-RADANT lens with electronic beam scanning for the Ka frequency band is presented. The prototype of the antenna consists of a 2bit Radant lens installed on the aperture of an E-sectorial horn antenna. A pair of grids, with rectangular slot antenna printed on dielectric substrate with PIN diode switch as load in each node generates 90° phase shift of the incident wave with reflection coefficient lower than -4.3 dB, and a transmission coefficient above -0.34 dB. The lens performance designed with three pair of grids, over an E-polarized plane wave, is experimentaly verified. Using a mathematical model for the design, the RADANT lens geometry and the adecuate configuration of the bias switches have been obtained, reaching electronic beam-steering angles of 11.35° and 8.6°, both of them with directivity greater than 14 dB.

This paper aims to analyze if the information, attitudes and willingness towards the water care are determinants of water consumption on the domestic sector. As a basis of this study, the per capita water consumption of 1100 households located in Monterrey, Mexico was analyzed. The Ordinay Least Squared method was employed to estimate a demand function, which includes the price of the service, the income of the individuals as well as a set of variables that capture the information available to the individuals about water care, the proactive attitudes and their willingness toward the household water care. Results indicate that price, income and the proactive attitudes are variables that explain water consumption. Therefore, it is important to stimulate these pro-ecologial attitudes in the society to conserve this natural resource and contribute to reach a sustainable water consumption.

Seventy percent of water is used in agricultural activities worldwide. However, due to the uncontrolled growth of the population and the contamination of superficial fresh water bodies the water scarcity has augmented, for this the availability of good quality water for agriculture is limited. One of the main pollutants is antibiotic resistant and potentially pathogenic bacteria. P. aeruginosa is a bacterium that normally is found in water and soil, it is pathogen from animals and plants. This bacterium has been considered a resistance phenomenon due to the diversity of mechanisms that contain which represent a potential risk to the population.Method: Samples of agricultural usage water were collected, of which P. aeruginosa was isolates and identified at the biochemical and molecular level. Also, the distribution of virulence genes was analyzed by PCR. The resistance to 20 antibiotics was tested by disk diffusion and microdilution assays. Even more, heavy metal resistance was analyzed by microdilution assays.Results: Forty-six P. aeruginosa were identified at molecular and biochemical level, the bacteria were potentially pathogenic because the following virulence genes was detected, algD and toxA in100% of bacteria, lasB in 97.8%, plcH in 95.6%, plcN in 91,3% and exoS in 89.1%. High rates of resistance were detected in bacterial isolates for ampicillin, ceftriaxone, chlroramphenicol, cephalotin, cefotaxime, nitrofurantoin, kanamycin, streptomycin and tetracycline. Similarly, susceptibility was detected mainly to ceftazidime, gentamycin, imipenem, tecarcillin, aztreonam, levofloxacin, netilmicin and carbenicillin. All bacteria were multirresistant as they tolerate between 8 and 11 antibiotics. According to the observed resistance patterns bacteria were classified in 11 groups. Whereas, metal tolerance was observed mainly for Cu+2, Zn+2, Ba+2, Pb+2 y Se+4. Conclusion: P. aeruginosa isolated from agricultural usage water samples in the studied zone are potentially pathogenic due to the presence of virulence genes. Even more, high rates of antibiotic and heavy metal resistance were observed. 

The limits or frontiers which configure the politico-administrative divisions of state entities are a product of older historical processes and social constructions involving the participation of physical-natural configurations, legal rulings and actors exercising their power and control to lend sense and direction to the territorial process, which is transformed into a sphere of struggle and interests centered on maintaining territorial dominion. This involves thinking of social space-time according to two variables, formation and configuration, in order to explain how the political, social and natural actors acted upon space, producing places and so revealing dominance of territory.Method. To understand the territorial process of the dividing line and the configuration of the states it is necessary to analyze: the legal rulings from the viceregal period; the policies and strategies that the congresses of the federal entities used to determine their jurisdiction; court cases from the viceroyalty up to Mexican independence; the history of the plans; the development of shape through time from the origin of the shape, and the use of geographic information systems to geo-reference archaic cartography on a modern map.Results. Through an analysis of the territory of Gachupines can be observed that there are agents of socio-spatial change from the viceroyalty to the consolidation of Mexican states by determining the configuration of adjoining federal entities, the analysis of place lets us see the model, outline and territorial organization implemented during the viceroyalty, the nature of its frontiers and its persistence.Conclusion. Geohistorical analysis is necessary to ensure a coherent sequence of territorial processes, where historical phenomena establish the pattern and causes of later historical events which emerge as a consequence and effect of the continuity and duration of the practices of the actors, as well as their projects and aspirations regarding place.

C-Reactive Protein (CRP) is one of the plasma proteins that appear in the acute phase of inflammation. Periodontitis is associated with elevated levels of CRP in adults and with its decreasing after treatment. On the other hand, diabetes is a disease that compromises both the inflammatory and reparative response of the body and the periodontal tissues are particularly sensitive to its effect. Therefore, CRP can be useful for the diagnosis and determination of progression of periodontal disease (PD). The aim of this study was to assess CRP levels in patients with PD and patients with PD and type 2 diabetes (T2D). 60 subjects were included and divided into 3 groups: 15 patients with PD (Group 1), 15 patients with PD and T2D (group 2) and 30 patients systemically healthy (group 3). Each participant underwent biochemical tests: Protein C Reactive (NycoCard® CPR), HbA1c (NycoCard®) and blood glucose test. Weight, height, body mass index (BMI) and periodontal loss of attachment were registered. For diagnosis of periodontal disease, we followed the parameters of the 5th European Workshop on Periodontology. Kruskal Wallis test was used to evaluate the differences between the groups. Significant statistical differences were found when comparing the CRP concentration in the 3 groups (p<0.01), finding that the healthy group showed the lowest mean (4.88±0.08) and the highest mean values were shown in the PE groups (5.95±2.23) and EP/T2D (5.21±0.20). Also, significant differences (p<0.01) were found in the three groups, in relation to hemoglobin concentration, height, body mass index and periodontal loss of attachment. The results indicate that serum levels of CRP rise in patients with PD and in patients with PE and T2D. Although this difference was noted, there are several local and systemic factors that can potentially influence CRP levels and these represent a limitation and difficulty when interpreting the tests.

The objective of the study was to characterize the piloncillo producers with the purpose of contributing with information that allows to know the importance of the use of technology in the production of granulated piloncillo in the community of Aldzulup Poytzén, Tancanhuitz, San Luis Potosí. Non-probabilistic sampling interviewed 36 producers of piloncillo. The study of the scalar variables was performed by analysis of variance for comparison of means and correlation analysis. There were significant differences (p <0.05) between the technological level of the piloncillo producers (high, medium and low), however, there were no differences in the levels of production obtained between them. There is a restrictive link to the market motivated by marketing factors that leads to the sale of industrial piloncillo; 97.22% of the producers sell this type of piloncillo. The family agriculture of the piloncillo producers has a productive diversification in their activities related to agriculture and livestock (sowing maize, beans, fruit, hens, pigs). It is concluded that the production of granulated piloncillo is not only explained by the low technological level, since this type of piloncillo is produced by the three strata. In addition, the study corroborates the diversification of productive activities of family agriculture as a strategy to support this type of producers.

Fricke dosimetry was performed in radiation fields of 60Co and 137Cs, corresponding to the Gammabeam 651PT irradiator loaded with new 60Co sources and a new Gammacell-3000 Elan self-irradiator with 137Cs. This last irradiator was purchased with funds from CONACYT. The gamma photons of 60Co from Gammabeam are using for sterilization of industrial products as well as in studies of physical and chemical properties changes of solid and aqueous solutions samples which are of the interest in research at the National Autonomous University of Mexico (UNAM). However, the difference in energy of the gamma photons from 60Co (1.17, 1.33 MeV) and 137Cs (0.66 MeV) makes interesting changes in research samples such as polymers, new dosimetric materials, organic compounds, etc., which are currently researching at the Nuclear Science Institute (ICN-UNAM). In order to use the radiation fields of irradiators, it is important to determine the exposure dose. In this paper, a successful methodology by using Fricke chemical dosimeter is reported. In this dosimeter is carried out the oxidation reaction in acid to ferric ion of ferrous. Dose rates distribution, less than 99 Gy/min, was determined in the Gammabeam irradiator. In the case of 137Cs irradiator, 10.89 Gy/min, at the center of the irradiation chamber was obtained. This value is in agreement to that certified measurement given by the Gammacell-3000 supplier. Because the sources are nonpoint, the uncertainties associated to the gamma doses were determinated. The two irradiators have adequate dose rates to continue supporting scientific research on different substances and materials, and offer the irradiation service at semi-industrial scale.

Climate change can affect crop productivity in a particular region. The objective was to identify the variability in the production of dryland forage oat (Avena sativa L.) using a stochastic function and analyze their relationship with temperature and precipitation as affected by sceneries of climate change in the northwestern region of Chihuahua, Mexico. It was obtained 13 years of statistical information (2001-2013) at meteorological stations in the municipalities of Bachiniva and Namiquipa, using information on July, August and September months, where it is concentrated about 80% of annual precipitation. Information was taken from HADCM3 (2001) model that describes the behavior of climatic variables under pollutant emission scenarios A2 and B2 on the years 2050 and 2080. The changes in climate variables in the short term (2050) was taken and it is expected to increase both in temperature and precipitation, allowing in the case of Bachiniva improve the production of oats from 3.57 t/ha to 8.11 t/ha under pollutant emission scenario A2. In the long term (2080) a permanent increase in temperature is expected, and no matter how much precipitation improve, this will cause in the current oat producing regions fail to develop crops for harvest.

In this paper, we present the design, modeling as well as the implementation of a magnetic levitation system, consisting on a single-degree of freedom pendular beam, which is driven by means of an active magnetic bearing. The analysis includes the state space representation and, after a tangent linearization process, its transfer function is obtained. In addition, the characteristics of the device such as the electronic instrumentation and mechanical design are described. In particular, it is shown the design procedure of the electromagnetic actuator used, as well as its characterization to determine the proportional constant of the electromagnetic force with respect to a current input. Finally, some numerical simulations and experimental results of the implementation of some classic controllers in stabilization task are shown.