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Mexico's national electric grid comprises ten regional systems, with one isolated in the south of the Baja California Peninsula. In addition, providing electricity access remains a challenge in the country. Therefore, distributed renewable energy solutions are relevant to satisfy the electricity demand and promote grid development. Distributed renewable energy access (DREA) based on a wind energy conversion system integrated into low-voltage direct current (LVDC) networks is presented. The DREA is analysed and simulated under wind speed conditions measured and recorded for one year at Baja California Sur. A representative variability is applied to five type-4 wind turbines based on wind speed turbulence intensity analysis. The generated power is transferred through a bidirectional dual active bridge converter, controlled by a novel small-signal model using a single closed-loop proportional-integral control, owing to its modularity, power density, and ability to transfer power from LVDC to high-voltage direct current. The effectiveness and robustness of the proposed DREA are assessed via a complete mathematical model, corroborated by the simulation results in MATLAB-Simulink®, and validated by experimental results using the real-time simulator Opal-RT Technologies® and laboratory prototyping. The results indicate a DC-link voltage compensation and integration of a power capacity of 150 kW in the LVDC networks with an efficiency of 94%.

El uso de lixiviado de lombriz para nutrir las plantas y el uso ef iciente del agua en los cultivos es importante en la producción de alimentos. El objetivo del estudio fue evaluar la respuesta de dos dosis de lixiviado de lombriz con dos métodos de riego en el rendimiento del chile jalapeño (Capsicum annuum) y algunas características químicas del suelo. El experimento se llevó acabo en la Facultad de Agricultura y Zootecnia de la Universidad Juárez de Durango (UJED), México en el año 2013 y 2014. Las unidades experimentales fueron distribuidas al azar con cuatro repeticiones bajo un diseño de parcelas divididas, donde la parcela principal fue el método de riego, por goteo al 60% de la evaporación (EV) y superf icial por surcos al 80% de EV, la subparcela fue la fertilización de 2400 y 4800 L ha-1 de lixiviado de lombriz. Se encontró un rendimiento de fruto mayor con riego por goteo en ambos años de estudio (P

In the last decade, a large number of studies at the experimental level in electrochemical systems for energy storage devices have been performed. However, theoretical approaches are highly desirable to understand the physicochemical properties giving rise to energy storage phenomena. This work was intended to provide insights into the $in$ $silico$ design of novel nanocomposite materials formed by the Keggin polyoxometalate SiW12 anchored to an organic functional group $\varphi-X$ (with $X = -NH2, -OH, -COH$ and $-COOH$), linked to a carbon nanotube. In these systems, the Density of States around the Fermi level is enhanced, giving the composite material the capacity of facile electron transport that may be determinant at the charge/discharge cycling performed in energy storage devices. Charge transfer at the composite materials under study is greatest for the $\varphi-COOH$ functional group, yielding an attraction with the SiW12 cluster of the same order of magnitude as that of covalent nature. The rest of the functional groups induce a non-covalent interaction of the electrostatic type, mediated by a van der Waals attraction. Our proposed methodology may represent a tool to develop novel electrode materials that may improve the performance on energy storage devices, such as supercapacitors or Li$-$ion batteries., Comment: Research article. 43 pages, 5 figures

IntroductionThe use of most recent Transcatheter aortic valve implants (TAVI) in the treatment of symptomatic severe aortic stenosis (SAS) is evolving with expanded indications from inoperable/high-risk to intermediate and low risk patients. Consequently, TAVI outcomes must be monitored to highlight its value under real-world conditions. Our aim was to prospectively evaluate TAVI (SAPIEN 3) outcomes in terms of patient's health-related quality of life (HRQoL), clinical outcomes, and healthcare resource utilization (HRU).MethodsAn observational prospective study including all consecutive patients with SAS undergoing a transcatheter valve implantation with Edwards SAPIEN 3 valve (transfemoral access) was conducted in full accordance with clinical guidelines from the European Society of Cardiology. Patients were evaluated before the intervention (baseline), at discharge, and after one, six and twelve months from the implant. A thoughtful and systematic evaluation of patients’ HRQoL (EQ-5D 5L, the Short Form-36 Health Survey -SF-36- and the Kansas City Cardiomyopathy Questionnaire -KCCQ-), clinical endpoints (that is, cardiovascular mortality, and rates of stroke, major bleeding, myocardial infarction, and re-hospitalization), echocardiographic measurements, and HRU (that is, Length of stay-LOS- in ward/intensive care unit -ICU-) was implemented. Multivariate regression models were applied to test outcomes while controlling key risk factors (that is, patient’ severity at baseline).ResultsA total of seventy-six patients (fifty percent female, fifty-five percent of intermediate-high risk) with a mean age of 82.1 ± 4.78 years were included. Implant success was 97.34% and cardiovascular death was 2.6% at one year. Significant reductions in mean and maximum gradients were achieved and maintained during follow-up. Mean LOS in ward (5.2 ± 4.0days) and ICU (0.22 ± 0.64 days) were low. Statistically significant improvements were detected in the KCCQ overall summary scores, EQ-5D, and SF-36 (Physical component summary) - all adjusted - p ConclusionsTAVI represents a safe and effective innovation for SAS with clinical benefits translated into significant improvements in terms of HRQoL. Besides, the low HRU provides new insights for health-economic modelling and the optimization of limited resources of special importance under current pandemic situation.

Susceptibility and immune response of Argopecten ventricosus challenged with Vibrio parahaemolyticus were determined. Mortality and median lethal concentration of V. parahaemolyticus were assessed in scallop seeds and adults challenged by immersion. Histopathological analysis was done in adults challenged by immersion. The immune response was analyzed in adults by injecting heat-inactivated bacteria in the adductor muscle. Hemolymph samples were taken at 0, 8, 24, 48, and 72 h. Time zero corresponded to samples of scallop hemolymph before challenging with vibrio. In bioassays, scallops were fed with microalgae concentrate Shellfish Diet 1800®. Seeds and adults of A. ventricosus were susceptible to V. parahaemolyticus showing a LC50 of 623 CFU mL− 1 and 62,853 CFU mL− 1, respectively. V. parahaemolyticus toxins caused lesions in digestive glands of adults analyzed. Significant variations were observed in hemocyte number, phenoloxidase activity, and lysosomal hydrolytic enzymes, mainly at 8 and 24 h, post infection. Results confirm that seeds and adults of A. ventricosus are susceptible to V. parahaemolyticus infection, but seeds are more susceptible than adults. In adults, the immune response of A. ventricosus was modulated by V. parahaemolyticus.

Recientemente se han reportado residuos de plaguicidas en el ambiente como resultado de las aplicaciones de estos productos durante varias décadas. A nivel mundial se presentan problemas atribuidos a los efectos de la contaminación por plaguicidas sobre los recursos naturales; sin embargo, en México, no existen suficientes estudios de contaminación por plaguicidas. El objetivo fue evaluar la presencia de plaguicidas en suelos de siete localidades de cinco Municipios de la Comarca Lagunera en el estado de Coahuila, se realizó un muestreo de suelos a cinco profundidades (0-8, 8-23, 23-38, 38-53 y 53-68 cm) a razón de una muestra compuesta por hectárea para determinar el grado de contaminación del suelo por plaguicidas. Se utilizó el método soxhlet para la extracción de plaguicidas en la muestra y un Kuderna Danish, para la concentración. Se utilizó un cromatografó de gases. Se encontró que el díeldrin fue el único plaguicida organoclorado presente en los suelos estudiados; las capas superficiales del suelo (0-8 y 8-23 cm) mostraron las mayores concentraciones de díeldrin. El contenido de materia orgánica, el porcentaje de arcilla y el pH del suelo fueron las características que más influencia tuvieron sobre la concentración del díeldrin en el suelo, presentando los coeficientes de determinación más altos (r2= 0.99, 0.84 y 0.96, respectivamente). En los suelos de los predios particulares estudiados, se observaron las mayores concentraciones de díeldrin en la capa superficial (0-23 cm), esto en relación con los ejidos evaluados; estos valores fueron del orden de 2.57 y 1.22 ng g-1, respectivamente.

Farm size and land allocation are important factors in explaining lagging agricultural productivity in developing countries. This paper examines the effect of land market imperfections on land allocation across farmers and aggregate agricultural productivity. We develop a theoretical framework to model the optimal size distribution of farms and assess to what extent market imperfections can explain non-optimal land allocation and output in-efficiency. We measure these distortions for the case of Guatemala using agricultural census microdata. We find that due to land market imperfections aggregate output is 19% below its efficient level for both maize and beans and 31% below for coffee, which are three major crops produced nationwide. The regions with higher distortions show a higher dispersion in land prices and less active rental markets. We also find that the degree of land market distortions across locations co-variate with road accessibility and ethnicity and, in a lower extent, with education.

Agricultural production is a risky activity subject to several contingencies that make farming incomes unstable and unpredictable from year to year. Bakst, Sewell, and Wright (2016) report that the Economic Research Service of the US Department of Agriculture (USDA) identifies five types of farming risk: (1) human and personal risk (such as human health), (2) institutional risk (regarding governmental action), (3) financial risk (such as access to capital), (4) price or market risk, and (5) production risk (such as weather and pests). The HIV/AIDS pandemic in African countries in the early 2000s is an example of a human risk that affected agricultural output and labor supply and demand. Land expropriation, land reforms, and unanticipated changes in the agricultural tax system are examples of institutional risk that can depress investment in the agricultural sector. Nonavailability of funds in the formal or informal financial sector or high interest rates reflecting liquidity scarcity at the beginning of the crop season can limit area planted in a year. Uncertain crop prices at harvest time and input prices during the crop calendar can have severe impacts on farm income and become a social problem when affecting many farmers.

In this article, a technique for the reduction of total harmonic distortion (THD) in distributed renewables energy access (DREA) composed of wind turbines is introduced and tested under the wind speed conditions presented in Tamaulipas, Mexico. The analysis and simulation are delimited by a study case based on wind speeds measured and recorded for one year at two highs in the municipality of Soto La Marina, Tamaulipas, Mexico. From this information, the most probable wind speed and the corresponding turbulence intensity is calculated and applied to a wind energy conversion system (WECS). The WECS is composed of an active front-end (AFE) converter topology using four voltage source converters (VSCs) connected in parallel with a different phase shift angle at the digital sinusoidal pulse width modulation (DSPWM) signals of each VSC. The WECS is formed by the connection of five type-4 wind turbines (WTs). The effectiveness and robustness of the DREA integration are reviewed in the light of a complete mathematical model and corroborated by the simulation results in Matlab-Simulink&reg, The results evidence a reduction of the THD in grid currents up to four times and which enables the delivery of a power capacity of 10 MVA in the Tamaulipas AC distribution grid that complies with grid code of harmonic distortion production.

Introducción: La Comarca Lagunera, ubicada en los estados de Coahuila y Durango, México, es la región con la mayor producción de leche en el país. En esta región son comunes las explotaciones lecheras con áreas agrícolas para la producción de cultivos forrajeros, donde se aplican dosis excesivas de estiércol y se han reportado problemas de contaminación del agua por nitratos; por lo tanto, es importante generar información sobre el nitrógeno disponible del estiércol (NDE) en un sistema de dos cosechas por año. Método: Se realizó un estudio con dosis crecientes de nitrógeno (N), en función del requerimiento de N del cultivo (RNC), utilizando urea, estiércol de corral (EC) y estiércol del separador de sólidos (ESS) como fuentes de N, en cultivos de maíz forrajero en primavera-verano y triticale en otoño-invierno. Se evaluó el rendimiento de los cultivos y el NDE en ambos tipos de estiércol.Resultados: El rendimiento de materia seca de maíz fue similar en todos los tratamientos, de 13.9 a 15.5 t∙ha-1, excepto en la dosis de 133% RNC con ESS, que tuvo el rendimiento más bajo. En triticale, las diferencias en rendimiento fueron no significativas. En maíz, la dosis de 428.6 kg∙ha-1 de N total con EC y de 449.6 kg∙ha-1 de N total con ESS, tuvieron la misma extracción de N (Nex) de 141.2 kg∙ha-1, equivalente a la dosis de 185 kg∙ha-1 de N con urea, que corresponde al 100% del RNC. Lo anterior indica una disponibilidad de N de 43.2% en EC y 41.1% en ESS. En el ciclo de invierno, el N disponible fue de 19.5% y 11.1% en EC y ESS, respectivamente.Conclusión: El N disponible de ambos tipos de estiércol, EC y ESS, abasteció de manera suficiente a dos cultivos forrajeros. Los valores de NDE fueron similares en ambos tipos de estiércol cuando se estimó en ciclo de primavera-verano, pero en otoño-invierno el NDE fue mayor en el estiércol de corral.

This article contains data on nanoporous carbon materials coming from lignocellulosic components. Such data is directly related to the research paper “Insights into the design of carbon electrodes coming from lignocellulosic components pyrolysis with potential application in energy storage devices: A combined in silico and experimental study” [1]. In this work, the geometrical parameters of nanoporous carbon systems were found with Molecular Dynamics (MD) simulations at the ReaxFF level. The tridimensional structures of such carbon systems are given in Cartesian coordinates. They were computed at different heating rates, simulating the conditions observed in pyrolysis processes of Agave angustifolia leaves, which were carried out in a solar furnace. Nanoporous carbon systems are characterized with radial distribution functions (RDF) and ring distribution profiles. Keywords: ReaxFF simulations, Energy storage, Pyrolysis, Nanoporous carbon

A density functional theory study was performed on a series of organic photovoltaic materials with a promising potential to be implemented as the active layer in a solar cell device. A thorough analysis on the molecular structure at ground and excited state revealed that some of the systems in the series of molecules observed in the ground state is dramatically altered in the first excitation. The dihedral deviations could be addressed as a ruling mechanism behind isomerization and its influence in the opto-electronic properties. The computation of absorption spectra at ground and excited state geometries showed a significant shift in the absorption maxima, presumably due to such geometrical changes. Furthermore, the computation of dipole moments gave us insights into the possible charge transfer from the OPV material to an acceptor in a solar cell device. This is critical when the system is implemented in such a device. Additionally, relevant photovoltaic parameters were collected, and a candidate series of OPV systems was proposed as potential materials for the heterojunctions of a solar cell device. The given theoretical methodology and the photovoltaic data computationally obtained may aid in the in silico design of novel donor materials for the new generation of solar cells.

Concentrated solar energy is a promising source of energy which is currently attracting many efforts to enhance its exploitation. In particular, parabolic trough collectors for low enthalpy processes is an emerging technology. Lately, many work is done focused on the improvement of these devices. One technique to achieve this is by augmenting the heat transfer in the receiver tube by inserting a twisted tape in the tube. In this work, we develop a thermodynamic model framework to analyse the performance of a parabolic trough collector with a twisted tape insert. We find the set of conditions under which a twisted tape insert is useful to boost the performance of a parabolic trough collector. This set of conditions corresponds to devices with low twisted ratios operating at low Reynolds numbers. The proposed model is supported with experimental data.

This article analyzes the demand for a simple rainfall-based weather insurance product among farmers in rural India. We explore the predictions of a standard expected utility theory framework on the nature of demand in terms of price, the basis of the hedge, and risk aversion using data from a randomized control trial. We find that demand behaves as predicted: it falls with price and basis risk and is hump-shaped in risk aversion, with price sensitivity decreasing at higher levels of basis risk. We estimate a negative price elasticity of 0.58 and find that doubling the distance to a reference weather station decreases demand by 18%. These results indicate that improving pricing and quality of insurance products can directly increase demand. In addition, we examine the impact of insurance training relative to other mechanisms designed to increase understanding. The evidence suggests that increased incentives to learn or learning by using are more effective at increasing both understanding and demand. Finally, we contribute to the scarce evidence on the demand for insurance over time. In terms of our main interventions, we find that the effect of premium subsidies persists over time, while the impact of investments in new weather stations diminishes and the effect of increased training in the first season seems to disappear during the second season. Importantly, while having previously purchased insurance does not encourage future uptake, receiving a payout does. This could reflect issues of trust in the product or the insurance company, and constitutes an important topic for future research.

A substantial literature has analyzed the challenges around weather index insurance, yet an important design issue has been generally overlooked. Most index insurance products have so far been characterized by a one-size-fits-all payout structure, intended for a representative farmer, at the cost of ignoring considerable heterogeneity in risk profiles. This paper provides unique evidence on the ways in which heterogeneity in farmers’ risk exposure affects their demand for insurance. We analyze a set of flexible insurance products against excess rainfall and exploit the substantial variation in insurance portfolios demanded by farmers. We explore the relevance of alternative sources of heterogeneity by extending a simple expected utility decision model and relying on structural estimation to test their significance. We find important aspects of farmer heterogeneity directly affecting their demand for insurance. We quantify the benefits of a flexible scheme by comparing farmer welfare to that achieved under alternative counterfactual insurance options.

Background Studying microRNA networks during heart development is essential to obtain a better understanding of developmental defects and diseases associated with the heart and to identify novel opportunities for therapeutics. Here we highlight the advantages of chicken embryos as a vertebrate model for studying intermediate processes of heart development. Avians develop a four-chambered heart closely resembling human anatomy and they develop ex utero, which makes them easily accessible. Furthermore, embryos are available all year with a steady supply. Results In this report we established a novel method for the knockdown of microRNA function by microinjecting AntagomiRs into the chicken heart in ovo. Our approach enables the targeted delivery of antagomirs into a locally restricted area and is not impacted by circulation. After further embryo development the successful miRNA knockdown was confirmed. Loss of function phenotypes can be evaluated rapidly, compared to more time-consuming genetic ablation experiments. The local application avoids potential systemic effects of microRNA knockdown, therefore allowing the assessment of impacts on heart development only. The method can be adjusted for different stages of chicken embryos (HH13–HH18) as well as for knockdown or targeted overexpression of coding genes. Conclusion In conclusion our method allows targeted and locally restricted delivery of Antagomirs to the heart leading to successful knockdown of microRNA function. This method enables rapid phenotypic assessment, for example by gene expression analysis of multiple cardiac genes.

Nanocarbon materials have attracted attention in the last decade due to their broad range of applications in solid-state devices. Particularly, nanocarbon has intensely been implemented in energy storage systems such as Li-ion batteries and supercapacitors. Furthermore, it has also been shown that the structural features of carbon substrates are determinant on the final characterization as an electrode of such kinds of devices. Different experimental approaches have traced the development of carbon substrates as electrodes on the improvement of the performance of a device to store electronic charge. Nevertheless, several processes involved in the description of charge retention are unclear or they are subject to debate. Consequently, the intense study at the fundamental level of such processes plays an important role to fully understand the mechanism behind charge storage, such as the nature of bonding with other substrates as metallic oxides, or the role of ion transport at the carbon interface. In this sense, the present chapter is intended to provide a comprehensive review of relevant experimental results that have inspired theoreticians to apply state-of-the-art methodologies to give insight into the physicochemical phenomenology resulting from charge retention. Furthermore, we also reviewed those cases where density functional theory and molecular dynamics simulations act as reliable schemes to be implemented on the study of structural features and electronic structure properties of carbon and its interaction with metallic oxides. We also present a review of theoretical results emerging in our group, and their intersections with data coming from the laboratory. Finally, we introduce a proposal composed of different avenues that a multidisciplinary group may be able to track in order to provide new insights to gain a profound knowledge of carbon-based electrodes at the atomistic level, and to coordinate the design of novel materials aimed to store energy with higher efficiencies and ecofriendly properties.

A study on the dynamic of transport and occurrence of ozone in the air basin of the Puebla-Tlaxcala Valley (PTV) was performed between March and April 2012. The ozone (O 3 ), nitrogen oxides (NOx) and several meteorological variables were measured at the surface level in the rural sites of Huaquechula (HUAQ), Chipilo (CHIP), and Amozoc (AMOZ). The vertical O 3 profile and the associated meteorological conditions, were measured intermittently in CHIP. The 1 hour Mexican air quality standard of 0.095 ppm for O 3 , was exceeded in five and one days in CHIP and AMOZ, respectively. A rapid increase in the morning for O 3 levels was observed in the three sites and was associated with the mixing of O 3 above the inversion layer once started the growing of the turbulent mixing layer. Unusual O 3 evening events of around 0.080 ppm were recorded for several hours in the three sites that could be associated with the recirculation of air masses with ozone formed within the VPT and O 3 advectively transported from the Cuernavaca-Cuautla Valley. The vertical O 3 profile showed an increase with height at concentrations even higher than those observed at the surface, and the 2-D analysis of backward trajectories suggested favorable conditions for O 3 transported from the free troposphere to the surface. It is concluded that the implementation of control strategies in the VPT should consider the influence of the inter-basin exchange, the meteorological local and synoptic seasonality, and the possible contributions of O 3 from the free troposphere and not be limited to local conditions.

Aim To describe the nature of care received by patients measured through the Caring Behaviours Inventory. Background Professional nursing practice combines two dimensions of caring: instrumental care and expressive care. Instrumental care focuses on physical health needs, in terms of efficiency and employs interventions based on evidence. Expressive care is patient‐centred and based on the interpersonal relationship. It requires caring attitudes that include respect, kindness, sensitivity and patience. The Caring Behaviours Inventory is a tool designed to assess the care expressed through the behaviours nurses perform, contextualised within the Jean Watson's Theory of Human Caring. Methods A systematic review following PRISMA recommendations. Scopus, PubMed and CINAHL databases were consulted using the keywords “Caring Behaviours Inventory” AND “Nursing”. The Joanna Briggs Institute tool was used for the quality appraisal. A conceptual analysis and a thematic synthesis were performed for data extraction. Results 11 articles were selected. Three categories were identified: nature of caring, congruence between perceived care by patients and nurses, and factors associated with the expression of care. Discussion An emphasis on care of an instrumental nature was identified. The perception of patients differs from that of nurses, patients perceive a lower level of expressive caring than the one nurses believe to deliver. Caring behaviours are affected by the working environment, nurses' emotional intelligence and coping skills, and socio‐demographic characteristics. Conclusion This paper described the findings of previous research regarding the nature of care that is transmitted and received in clinical practice. Results highlight an emphasis on the instrumental aspect of the nursing care according to the patients' perception. Relevance to clinical practice Findings summarised in this review could contribute to a better understanding of the nursing care. Results reported in this paper could also help to improve the quality of care delivered by nurses as well as patient‐centeredness.

Preventive measures are a priority in those groups that perform intense physical efforts without physical preparation and that can also be overweight or obese. One of the groups that reflect these characteristics is the costaleros of the Holy Week of Andalusia, Spain. This paper aims to describe the effect of obesity on blood pressure. A descriptive cross-sectional study was conducted on 101 costaleros. The anthropometric measures were determined through segmental impedance. Cardiac recovery and anaerobic power were measured through the Ruffier&ndash, Dickson test and the Abalakov test, respectively. Blood pressure was measured when the individuals were at rest. The Kruskal&ndash, Wallis test was applied for of continuous parameters and the X2 test for dichotomous measures. Binary logistic regression models were used for the subsequent analysis with R-square and Receiver Operating Characteristic (ROC) curves. The average population was 28 years of age, 173.7 cm tall, and 82.59 Kg weigh. The excess of body fat was 11.27 Kg and Body Mass Index was 27.33 Kg/m2. 72.3% showed abnormal blood pressure and 68.2% were overweight. 32.7% had a waist-hip ratio higher than 0.94. The probability of presenting abnormal blood pressure was higher among the subjects whose fat content was higher and muscle content was lower.

The use of eco-friendly materials for the environment has been addressed as a critical issue in the development of systems for renewable energy applications. In this regard, the investigation of organic photovoltaic (OPV) molecules for the implementation in solar cells has become a subject of intense research in the last years. The present work is a systematic study at B3LYP level of theory performed for a series of 50 OPV materials. Full geometry optimizations revealed that those systems with a twisted geometry are the most energetically stable. Nuclear-independent chemical shifts values show a strong aromatic character along the series, indicating that a possible crystallization in solid-state may rise, via a $$\pi {-}\pi $$ stacking. This may play a role in the design of a solar cell device. The absorption spectra in the series were also computed using time-dependent DFT at the same level of theory, indicating that all spectra are redshifted along the series. This is a promissory property that may be directly implemented in a photovoltaic material, since it is possible to absorb a larger range of visible light. Nonlinear optical properties were also estimated with the aid of a PCBM molecule as a model of an acceptor, and a final set of systems was identified with outstanding electronic structure properties related to the performance of solar cell materials. The methodological approach presented in this work may aid in the in silico-assisted design of OPV materials.

Introducción: La producción de forrajes en la Comarca Lagunera se realiza de forma intensiva, por lo que no hay un intervalo de tiempo que le permita al suelo recuperarse. El cultivo de maíz forrajero en esta región es el segundo en importancia, por lo que es imprescindible buscar estrategias que nos permitan recuperar la calidad de los suelos sin que el rendimiento se vea afectado. Método: Se evaluó la producción de maíz forrajero con el híbrido P3258W de Pioneer. Se usó un bioinoculante comercial para suelo con dosis de 0, 20 y 40 l ha-1, en combinación con siete fuentes de fertilizante: vermicompost en 5 y 10 t ha-1, estiércol de bovino lechero en 80 t ha-1, fertilizante inorgánico (191-75-30 de NPK), un fertilizante comercial orgánico a dosis de 2.5 y 5 l ha-1 y el testigo. El diseño experimental fue en bloques al azar, con arreglo de tratamientos en parcelas divididas, donde la parcela mayor fue el bioinoculante y la parcela menor la fuente de fertilización. Las variables que se evaluaron fueron rendimiento de forraje verde y seco, altura de planta a la cosecha; antes y después de la cosecha se evaluó en muestras de suelo: materia orgánica, pH, conductividad eléctrica, nitrógeno inorgánico y fósforo. En muestras de planta tomadas en la cosecha se determinó nitrógeno y fósforo totales. Resultados: Hubo diferencia significativa en cuanto al rendimiento respecto a la fuente de fertilizante y el mejor tratamiento fue donde se aplicó estiércol a una dosis de 80 t ha-1. En las características del suelo: materia orgánica, nitrógeno y fósforo se observaron diferencias significativas entre dosis de bioinoculante del suelo y entre fuentes de fertilizante. Para el nitrógeno en planta, las diferencias fueron significativas entre dosis de bioinoculante del suelo y entre fuentes de fertilizante. En la concentración de fósforo en planta, el análisis mostró una interacción significativa entre dosis de bioinoculante del suelo y fuentes de fertilizante. Conclusión: Se puede llevar a cabo la producción de maíz forrajero utilizando bioinoculantes y abonos orgánicos sin que el rendimiento se vea afectado y se favorece el contenido de materia orgánica, nitrógeno y fósforo en el suelo.

En el presente estudio se evaluó el efecto de la fertilización con estiércol bovino solarizado y vermicompost a diferentes niveles en el cultivo de sandía variedad PEACOCK WR124. Se utilizó un sistema de riego por cintilla. Los factores de estudio fueron el estiércol bovino (FE) y vermicompost (FV) en diferentes niveles. En el caso del FE: 0, 40, 60, 80 t ha-1, fertilización qímica (FQ) 120-60 y para FV: 0, 3, 6, 9 t ha-1. Se utilizó un diseño experimental de bloques al azar con arreglo en franjas con tres repeticiones. Las variables de suelo estudiadas fueron: conductividad eléctrica, pH, materia orgánica y nitratos en tres profundidades (0 a 15, 15 a 30 y 30 a 45 cm). Se evaluó el rendimiento y sólidos solubles totales en fruto. Los valores mayores de materia orgánica (3.23%) y nitratos (39.71 mg kg-1), se presentaron en la profundidad de 0 a 15 cm, correspondientes al tratamiento de 80 t ha-1 de estiércol bovino solarizado y 9 t ha-1 de vermicompost, mostrando un incremento por efecto de la interacción de los abonos orgánicos. Se encontró diferencia estadística significativa en CE y pH del suelo. Los mejores rendimientos se asociaron al tratamiento de vermicompost de 3 t ha-1 con el tratamiento químico, con rendimiento de 32 t ha-1.

The pen shell Atrina maura has economic importance in northwestern Mexico, but limitations to rear larvae in hatcheries increased the interest of scientists and producers to study aspects of reproduction and larval cultivation. Reproductive and larval performances of the species were studied in relation to the origin (depth, phases of tidal cycle) and gross condition of broodstock. The results were correlated to variations in water temperature and concentration of chlorophyll a. Tide influenced spawning response, which was between 40% and 100% successful in broodstock collected during rising and falling tides and only 10% at high or low tides (this percentage corresponds tomales only). The number and size of released and fertilized eggs and the survival of larvae were higher in pen shells collected at 5–8 m depth, compared with those collected at less than 1m. The number and size of released and fertilized eggs, number of veliger larvae, and the survival and growth rate of larvae were significant...

Correlations among atomic structure, chemical reactivity, charge transfer and electronic structure properties were investigated in nanoporous carbon at different mass densities. The model structures have been generated by a heat-quench procedure using Density Functional Theory calculations and first-principles quantum molecular dynamics simulations. Reactive points seem to be highly dependent of the local structure of the material. The results showed that sponge-like nanoporous carbons are good candidates to graft polyoxometalates since they presented a stronger interaction with the carbon substrate. The charge transfer is from the nanoporous carbon to the polyoxometalate and a covalent interaction was observed for a density of 0.75 g/cm3. Our materials developed an electronic band around the Fermi level.

This study was conducted in two stages, in 2006 the formation of cross, in the experimental field of the Universidad Autonoma Agraria Antonio Narro Unidad Laguna (UAAANUL), and the evaluation of the same in 2007; at two locations with three environments, a locality was the experimental field of UAAANUL during spring and summer cycles and another location was the Niagara, Municipality of Aguascalientes, during the spring cycle. The genetic material used consisted of three groups of lines: the first group formed by four lines from the UAAANUL, the second group, two lines from INIFAP, and the third group, 10 lines of the International Center for Maize Improvement and Wheat (CIMMYT). The main objective was to estimate the effects of general combining ability (GCA) of the lines, and the specific combining ability (SCA) of their crosses and heterosis, to estimate its use in a breeding program. Estimates of general combining ability (GCA) and specific combining ability (SCA) were obtained using an analysis of line x line. To forage yield (FY), B-40 (16.84 t·ha-1) and AN-447 (1.54 t·ha-1) and to grain yield (GY), AN-388R (2.31 t·ha-1) had the greatest effect of GCA in both types of yield. The greatest effects of SCA for (FY) were cross AN-447XCML-264 (17.56 t·ha-1) and AN-388RXCML-319 (16.54 t·ha-1), in (GY) were cross AN-447XCML-315 (1.94 t·ha-1) and B-40XCML-319 (1.78 t·ha-1). For heterosis, higher value in forage yield was cross AN-447XCML-264 (20.7%), in grain yield, were B-40XCML-319 (27.1%) and B-32XCML-319 (22.1%) crosses. These results show that it is possible to structure a hybrid program using best lines from CIMMYT, INIFAP and UAAANUL.

Milk has become one of the most volatile agricultural commodities in the international market. High volatility of commodity prices and their implications for food security are clearly among the most important issues facing policy makers today. Thus, a deeper understanding of the magnitude, speed, and symmetry to which global milk prices are being transmitted to domestic prices at the farm gate level is a fundamental factor in the design of appropriate policy measures oriented to reduce not only the level of milk price volatility, but also poverty and food insecurity. The purpose of this article is therefore to assess the dynamics of the relationship between global and domestic milk prices. [Econ Lit Classifications: Q11, Q13, Q17].

Organic amendment is a good alternative to improve soil fertility to maintain or increase crop forage and grain production. After several times of organics application (crop cycles) is important to follow soil physical and chemical parameters to avoid soil pollution such as salinity and nitrate. The main objective of this study was to maintain good triticale forage production and soil quality after seven years in plots where two factor were studied:caw manure amendments; 0, 40, 80, 120 and 160 t ha -| and one chemical level with 150-100-00 kg ha-1 of Nitrogen, Phosphorus and potassium, respectively just to compare manure amendments. After This time to decrease soil salinity and high levels of nitrate triticaleforage was planted in the same plots using two varieties without manure and chemical fertilizer application. Triticale variables measured were green forage and soil parameters such as; Electrical Conductivity (EC), Organic Matter (OM), Hydrogenpotential (Ph) and Nitrates (NO-3). Results indicated that triticale forage production was high in all plots were caw manure was applied after three years than the control and chemical fertilizer level, Also, the chemical soil parameters such as salinity, and nitrate decrease to adequate levels of 4 mmhos cm -1 in salinity and less than 20 ppm of nitrates. Triticale forage production was better in all plots with caw manure application with more than 25 Mg ha-1 that's is the triticale average production in this region and more of 100 % than the control and chemical fertilizer plots. According to these resultscaw manure amendments is a good alternative to get high triticale forage production and maintain a good soil quality.Read Complete Article at ijSciences: V5201602937 AND DOI: http://dx.doi.org/10.18483/ijSci.937

Carbon has shown to give excellent performance in electrodes of energy storage devices, such as Li-ion batteries and supercapacitors. The grafting of polyoxometalates (POM) at carbon has scarcely been explored at the theoretical and experimental level, and the mechanism behind the chemical bonding between POM and carbon has not been fully understood. In order to give insights into these issues, an electronic structure study was carried out on the following POM systems adsorbed on carbon: PdMo12, RuNb12, SiMo12, PMo12 and SiW12. The prediction of the existence and chemical stability of PdMo12 and RuNb12 systems is reported for the first time. All systems were fully optimized with the nominal charges and also neutralized with counterions, as a benchmark to elucidate an optimal scheme that models the interaction in these nanocomposite systems. The POM/carbon attraction lies at about 250 pm in average, which may be addressed to a non-covalent bonding of the electrostatic-type, where the van der Waals contribution may also play a role. The density of states is evidently increased around the Fermi level in all POM/carbon systems. This may be due to the rising of new trajectories that ions may follow at the electrode of a solid-state device, such as a supercapacitor, giving as a result the strengthening of density current values and pseudocapacitive properties than those observed in pristine carbon systems. It was found that the SiWO12 and RuNb12 POM systems may be more feasible to be adsorbed on carbon substrates and may not require functional groups to allow POM retention. These systems represent potential candidates to be considered in nanohybrid electrodes for solid-state applications.

National decision makers must understand the degree to which their country and population groups within it are exposed to the negative effects of higher global food prices or could exploit new economic opportunities offered by higher prices. This paper provides a conceptual overview of the range of data and analyses that will permit leaders and analysts serving them to assess the broad implications of higher global food prices for a country and its population groups. What we find is that there are a relatively small number of types of policy responses that governments might take in the face of a food price rise. Consequently, relatively well-defined sets of data need to be compiled and types of analyses used by government to generate the information needed to broadly guide efforts to prevent food price increases from becoming crises and to derive any possible benefits. International joint action can be employed profitably both to collect this data and to build national capacity to conduct the analyses needed to guide policy formulation and general program design in the face of the risks and the opportunities of higher food prices and to evaluate the effectiveness of those policy responses.

Keggin polyoxometalate structures are molecular clusters that, anchored to carbon matrices, have been used to form electrodes for energy storage devices, such as lithium batteries and supercapacitors. $$[{\text{PMo}}_{12}{\text{O}}_{40}]^{3-}$$ polyanions (PMo12) are examples of this kind of nanostructures that, grafted on amorphous carbon, have the capability to enhance the capacitive properties of these electrochemical ensembles. However, there is yet a poor understanding of the fundamental mechanisms for bond formation between them and carbon structures. It has been found experimentally that the presence of functional groups such as φ-NH2 and φ-OH assists on the chemical absorption of PMo12, but there is not enough information on the actual mechanism of the process. In order to gather further knowledge on these issues, we have performed quantum mechanical calculations, based on the density functional theory of atomic arrangements using graphene as carbon structure model, different functional groups, and PMo12. Our aim was to look for the nature of bonding among them, and to dig into the charge properties to relate them with the experimental observation. From the computations performed with PMo12 polyanion near to a graphene sheet, with and without the presence of functional groups, we conclude that there is a non-covalent/electrostatic bonding, made of weak $$\pi$$ – $$\pi$$ stacking interactions between PMo12 and graphene. Calculations show that φ-NH2 and φ-OH functional groups are able to form covalent bonds with PMo12 in top and side fashion arrangements, being the latter the most stable. This is a powerful argument to explain the empirical observation on these groups, enhancing the PMo12 adsorption over carbon structures. We also found that the presence of the functional groups together with PMo12 creates electronic states that may act as alternative pathways that ions can track within electrochemical cells. Our results offer first-principle information relevant to the understanding of these composite materials, and the methodology could be directly applied to other Keggin structures or different functional groups, attached to graphene, to find potential advantages for energy storage devices.

laboratory. In each experimental unit we cultured 66,666 juveniles with a shell length of 1.57 ± 0.05 mm (n ¼ 20). In the Nestier trays, growth was 4–6 mm/day, with a survival of 15%. In the upwelling-type units, growth was 5–6 mm/day, with a survival of 93%. ANOVA revealed significant differences (P < 0.05) in juvenile growth between the Nestier trays and the upwelling-type containers. Low juvenile survival in Nestier trays is attributed to clogging with wind-blown slime. However, a nursery of A. grandis juveniles in ponds requires further research to show its economic feasibility.

The second-order thermodynamic perturbation theory formulation of Barker and Henderson is used to derive the equation of state of the triangle-well fluid. This is combined with the rational function approximation to the radial distribution function of the hard-sphere fluid. Results are obtained for the critical parameters and the liquid–vapour coexistence curve for various values of the range of the potential. A comparison with available simulation data is presented.

This study analyses the welfare and poverty effects of the 2007–08 food-price crisis on households in Guatemala. Estimates reveal that the price increases negatively affected 96.4 per cent of households and resulted in a 1.1 per cent increase in the national poverty rate. On average, households lose 2.3 per cent of their expenditure capacity, and high food prices have a regressive negative effect. The total welfare loss for all households in the country is estimated to be nearly 2 per cent of national aggregate expenditure, but the cost of compensating the poorest households would be only 0.5 per cent of national aggregate expenditure.

Smallholder farmers are increasingly exposed to weather extremes but lack access to affordable insurance products for catastrophic crop damage. This paper analyzes the feasibility of Picture-Based Insurance (PBI) as a low-cost tool to improve coverage. PBI verifies insurance claims using smartphone pictures of insured plots, taken by farmers themselves, to minimize asymmetric information and costs of claims verification, while reducing basis risk compared to index-based insurance. A pilot implementation in the rice-wheat belt of India speaks to PBI being a feasible and valuable innovation to reduce downside basis risk in index insurance: nearly two-thirds of trained farmers took at least four pictures (roughly one per growth stage), which was considered sufficient for loss assessment; severe damage was visible from smartphone pictures in 71 percent of affected sites; and this was a significant improvement over alternative index-based products, which identified severe damage in at most 34 percent of affected sites. Keywords: Risk and insurance, Mobile technology, Basis risk, India, JEL classification: G220, O13, O16, Q14

The objective of this research was to evaluate the production and phytochemical quality of cucumber (Cucumis sativus) fruits, in response to the foliar application of different seaweed extracts. This study was carried out under shadow mesh conditions in the autumn&ndash, winter agricultural cycle at the Instituto Tecnol&oacute, gico de Torre&oacute, n, Torre&oacute, n, Coahuila, Mexico. The experimental design was completely random, using six treatments with six repetitions each. The treatments evaluated were: Macrocystis pyrifera, Bryothamnion triquetrum, Ascophyllum nodosum, Grammatophora spp., Macrocystis integrifolia, and a control treatment with inorganic fertilization. The substrate used was a mixture of sand and vermicompost. The yield, commercial size, and phytochemical compounds of the fruit were evaluated. Results showed that the yield using Steiner solution (6.75 kg m&minus, 2) was higher than that obtained with Bryothamnion triquetrum algae (6.07 kg m&minus, 2). Regarding the phenolic content, the extracts surpassed the control treatment, with Macrocystis pyrifera and Macrocystis integrifolia being statistically equal, with values of 47.37 and 43.73 mg equiv. of Ac. Gallic 100 g fresh weight, respectively. The antioxidant capacity by ABTS+ and DPPH+ methods was higher using the treatment with Macrocystis pyrifera algae with 149.4 and 454.1 &mu, M equiv Trolox/100 g fresh base, respectively. This treatment also presented the highest value of vitamin C with 5.07 mg/100 g fresh base, being 27% greater than the control treatment. Algae extracts increased the quality of the fruits by obtaining the highest antioxidant capacity, making their use a viable option to minimize the application of conventional fertilizers, thereby attenuating the effects on the environment and improving the health of the population.

Since the late 1980s, almost all Latin American countries have adopted a series of far-reaching economic reforms, especially trade, financial, and capital account liberalization. Increased economic openness has gone hand in hand with large financial inflows—particularly in the first half of the 1990s—and has brought new sources of economic growth. As a result, economies grew, inflation declined, and there was a big surge in foreign cap- ital inflows. Although overall growth slowed after 1995, the region has expe- rienced strong growth in the past five years, the best sustained performance since the 1970s. With the exception of a handful of countries, this economic growth has been accompanied by relatively modest inflation. Despite these positive results, virtually all Latin American countries share similar problems: uneven economic growth, unacceptably high poverty and malnutrition rates, and lagging agricultural growth. More than 60 percent of the region’s poor live in rural areas, where slow economic growth, unequal distribution of assets, inadequate public investment and public services, and vulnerability to natural and economic shocks are major policy issues. The 2007–08 food price crisis exacerbated these problems. Prior to the cri- sis, the region was considered relatively stable and capable of absorbing exter- nal shocks, thanks to its higher foreign exchange liquidity; decreased public sector and external borrowing needs; exchange rate flexibility; lower exposure to currency, interest rate, and rollover risks in public sector debt portfolios; and improved access to local-currency loans. Nevertheless, the food price cri- sis severely affected most of the Latin American countries in terms of inflation, especially food inflation.

This chapter describes the three most important Mexican scallop species (lion's paw: Nodipecten subnodosus; Pacific calico scallop: Argopecten ventricosus; Vogde's scallop: Euvola vogdesi), their ecology, fisheries and aquaculture. All commercially important scallops in Mexico occur in the Pacific Northwest and Gulf of California, especially in the lagoon systems along the coast in shallow waters to depths of about 100 m. The three scallop species are fast growing, reproduce early in life, and form large banks that have been commercially exploited over the past decades by hooka-diving from small fibreglass skiffs with outboard engines. As happened in many scallop fisheries around the world, exploitation is characterised by boom and bust phases. Commercial fisheries of Mexican bay scallop started in the early 1980s and represented the most important mollusc fishery in the country from 1985 to 2013, when the banks in Magdalena bay were diminished so much, that the fishery was closed. Vogde's scallop was only locally exploited for a short time, the lion's paw, however, has sustained a small commercial fishery in Ojo de liebre and Guerrero Negro lagoons from the early 1990s to 2010 with a maximum production of about 150 mt of meats. In 2010, the population crashed, probably due to a disease, the cause of which is still being investigated. This species was also fished at different sites in the Gulf of California (Loreto, Bahia de Kino), but on a much smaller scale. Today, all scallop fisheries in Mexico are in a serious crisis and are deemed unsustainable. Therefore, large efforts have been undertaken to develop commercial aquaculture of A. ventricosus and N. subnodosus. While hatchery techniques for the former are fully developed and commercial spat production has been accomplished routinely, hatchery production of the latter is still on a small scale, and no commercial spat supply is as yet available, despite a large number of scientific studies on the subject. Small-scale pilot and commercial cultures of both species have been conducted at >15 sites on the Baja California Peninsula and the coasts of Sonora and Sinaloa over the past two decades, with varying results. No active scallop cultures are in operation as of 2015, which shows that they have not been commercially viable for the most part. Lack of spat production, site selection, El Nino years, diseases, handling, market failures, competition with the capture fishery and mismanagement have been quoted as possible reasons, and the Mexican government does not have a comprehensive programme to promote scallop aquaculture. Unfortunately, the large body of scientific studies on scallop aquaculture in Mexico has not translated into an economic alternative for the aquaculture and fishing industry in the region. As fisheries in the region are clearly in decline, efforts should be strengthened to promote sustainable aquaculture of native species and thereby improve the livelihood of coastal communities.

Organic amendment is a good alternative to improve soil fertility to maintain or increase crop forage and grain production. After several times of organic applications (crop cycles), it is important to follow soil physical and chemical parameters to avoid soil pollution such as salinity and nitrate. The main objective of this study was to maintain good triticale forage production and soil quality after seven years in plots where two factors were studied: cow manure amendments; 0, 40, 80, 120 and 160 t ha-1 and one chemical level with 150-100-00 kg ha-1 of Nitrogen, Phosphorus and potassium, respectively just to compare manure amendments. After this, to decrease soil salinity and high levels of nitrate, triticale forage was planted in the same plots using two varieties without manure and chemical fertilizer application. Triticale variables measured were green forage and ential (Ph) and Nitrates (NO3). Results indicated that triticale forage production was high in all plots were cow manure was applied after three years than the control and chemical fertilizer level, also, the chemical soil parameters such as, salinity and nitrate decrease to adequate levels of: 4 mmhos cm-1 in salinity and less than 20 ppm of nitrates. Triticale forage production was better in all plots with cow manure application with more than 25 mg ha-1, that’s the triticale average production in this region and more than 100% of the control and chemical fertilizer plots. According to these results, cow manure amendments is a good alternative to get high triticale forage production and maintain a good soil quality.

Understanding the degree to which international food price volatility is transmitted to markets in developing countries is critical for helping design better policies to cope with volatility and protect vulnerable groups. This chapter uses a multivariate GARCH approach to model price volatility transmission from world grain markets to 41 markets in 27 developing countries. We found that maize prices are more volatile than rice and wheat prices and that prices in Africa are more volatile than those in Latin America and South Asia. International grain price volatility is most likely to be transmitted to domestic markets for wheat, followed by rice and then maize. Furthermore, international price volatility is most likely to be transmitted to markets in South America, followed by Asia, Africa, and then Central America. Price volatility transmission seems to occur more often when international trade in a commodity is large relative to the commodity’s domestic production or consumption.

This article provides a comprehensive analysis of the dynamics of volatility across major agricultural commodities in the United States. Volatility interactions across markets may lower the effectiveness of diversification strategies to mitigate price risks and should be taken into account when analyzing the pricing behavior of different agricultural commodities. We follow a multivariate GARCH approach to evaluate the time evolution of conditional correlations and volatility transmission across corn, wheat, and soybeans price returns on a daily, weekly, and monthly basis. The period of analysis is from 1998 to 2012. The estimation results indicate a lack of lead-lag relationships between corn, wheat, and soybeans price returns at the mean level. We find, however, important volatility spillovers across commodities, particularly at the weekly and monthly level. Wheat and corn seem to play a major role in terms of volatility transmission. Despite the supposed higher financial market integration of agricultural commodities, we do not observe that agricultural markets have become more interdependent in recent years.