Abstract: The article retrieves the narratives of Peruvian women in Arica (Chile) discussing the contradictions that structure for them a dialectical experience of motherhood. We will begin by synthesizing theoretical debates on the relationship between gender violence, patriarchy and gender inequalities in border areas. Then, we will discuss how pregnancy means for Peruvian women, doubly, a liberation and a chain, conditioning forms of self-awareness, while exposing them to violence. We will thus analyze the dialectic between rupture and permanence of male figures and the female overload linked to the reproduction of the family nucleus. We will also recover the relations between the Peruvian migrants and the mothers of their Chilean partners, expressing the contradictions and relational conflicts that emerge in the encounter of heterogeneous conceptions of motherhood. Finally, we offer an analytical synthesis, pointing out new research questions.

Resumen: El artículo recupera las narraciones de mujeres peruanas en Arica (Chile), discutiendo las contradicciones que estructuran para ellas una experiencia dialéctica de la maternidad. Partiremos sintetizando debates teóricos sobre la relación entre violencia de género, patriarcado y desigualdades de género en zonas fronterizas. Luego, abordaremos cómo el embarazo significa para las mujeres peruanas, doblemente, una liberación y un encadenamiento, condicionando formas de autoconocimiento corporal, a la vez que exponiéndolas a diversas violencias. Analizaremos, así, la dialéctica entre ruptura y permanencia de las figuras masculinas y la sobrecarga femenina vinculada a la reproducción del núcleo familiar. Abordaremos, además, las relaciones entre las migrantes peruanas y las madres de sus parejas chilenas, expresando las contradicciones y conflictos relacionales que emergen en el encuentro de concepciones heterogéneas de maternidad. Finalmente, ofreceremos una síntesis analítica, apuntando hacia nuevos interrogantes de investigación.

Abstract: There are recent technologies that can help counter soil degradation and sequester carbon. One is the application of biochar (biochar) to the soils. Biochar is a material produced by pyrolysis of waste biomass or organic waste from urban life. Mexico soils exhibit a strong physical, chemical and biological degradation, which has not been assessed in its proper dimension. Recent literature indicates positive experiences resulting from the application of biochar to the soil, generating an improvement of the physical, chemical and biological properties, which result in increased crop productivity. The biochar, a recalcitrant form of carbon incorporated into the soil, acts as a reservoir of long life of carbon, delaying its return to the atmosphere as CO2, a situation that would help to mitigate climate change. An additional benefit of this product is that the raw material for its production comes from a renewable source and municipal organic waste, which often constitute environmental pollution problems. The generation and soil application is a relatively recent technology or alternative, which has been little or not used in Mexico. Therefore, it is advisable to know more about it and its benefits. Little is known about the effect of the type of raw material used for the generation of biochar, the effect of the pyrolysis is used for production or the effect it has on plants, as well as the presence of substances that could be toxic to soil microorganisms or plants. To avoid unnecessary risks or adverse effects on its use, it is necessary to characterize the chemical and physical properties of different types of biochar and elucidating the effect of its application on soil properties and crops. The answers to the above questions and the effect of the application of biochar to soils of Mexico will serve to generate solid foundation and propose their use as practice for improvement and as a mechanism for carbon sequestration in the soil. The development of technological processes for making biochar, feasible to be implemented in Mexico, is a challenge for local technologists and a potential source of non-standard work, apart from the possibility of generating additional income to producers of agricultural and forestry sector and municipal entities that could transform organic waste into a product with commercial value. This paper is a review of the literature and some personal experiences of the authors.

Resumen: Los suelos de México exhiben una fuerte degradación física, química y biológica. Existen tecnologías para contrarrestar la degradación del suelo, ayudar a recuperar su fertilidad y secuestrar carbono, como la aplicación de biocarbón (biochar), que es un subproducto de la pirólisis de biomasa residual. Existen experiencias positivas derivadas de la aplicación de biocarbón al suelo, que generan una mejoría en sus propiedades físicas, químicas y biológicas, lo que se traduce en un aumento de la productividad de los cultivos. El biocarbón, por ser una forma recalcitrante de carbono, actúa como reservorio de larga duración de este elemento, retardando su retorno a la atmósfera como CO2, situación que contribuye a mitigar el cambio climático. Un beneficio adicional es que la materia prima para su producción proviene de residuos orgánicos, que a menudo causan problemas de contaminación ambiental. La generación de biocarbón y su aplicación es una alternativa tecnológica que ha sido poco o no empleada en México. El desarrollo de procesos tecnológicos para elaborar biocarbón, factibles de ser implementados en México, constituye un desafío para los tecnólogos locales. Adicionalmente, constituye una potencial fuente de trabajo, no convencional, para productores del sector agroforestal y entidades municipales, al generar ingresos extras dando valor agregado a los residuos orgánicos y al generar un producto con valor comercial. Poco se sabe del efecto que tiene en las plantas el tipo de materia prima empleada para la generación del biocarbón o, de la pirólisis que se usa para su producción; tampoco hay mucha información sobre la presencia de sustancias que pudiesen resultar tóxicas para los microorganismos edáficos o las plantas. Las respuestas a las interrogantes anteriores servirán para generar bases sólidas y proponer su uso como mejorador del suelo y como un mecanismo para el secuestro de carbono en el mismo.

La literatura sobre el aprendizaje organizativo ha presentado un notable desarrollo en las últimas décadas; sin embargo, aún existen vacíos en la comprensión de los factores que lo determinan. El artículo revisa la evolución en este campo desde el enfoque original de "la organización que aprende" hasta el enfoque más reciente de "la organización ambidiestra", aquella que es hábil para desarrollar simultáneamente sus aprendizajes de exploración y explotación. Se analiza el concepto de ambidestreza organizativa y su impacto en el desempeño empresarial y se propone un modelo que integra los factores que influyen sobre dicha capacidad (estructura, cultura, liderazgo, entorno y estrategia), los cuales configuran promisorias líneas de investigación en este campo.

Despite the remarkable progress attained by organizational learning literature in recent decades, a series of gaps in the understanding of the factors that determine said improvement still persist. The evolution of this field is reviewed, from the original approach of the "learning organization", to the newer perspective of the "ambidextrous organization", one that is able to simultaneously develop exploration and exploitation learning processes. We analyze the concept of Organizational Ambidexterity and its impact on business performance, and propose a model that integrates the factors influencing this capability (structure, culture, leadership, strategy and environment), which constitute promising research lines in this field.

A literatura sobre o aprendizado organizativo tem apresentado um notável desenvolvimento nas últimas décadas; no entanto, ainda existem vazios na compreensão dos fatores que o determinam. O artigo revê a evolução neste campo, desde o enfoque original de "a organização que aprende" até o enfoque mais recente de "a organização ambidestra", aquela que é hábil para desenvolver simultaneamente os seus aprendizados de exploração. É analisado o conceito de ambidestria organizacional e o seu impacto sobre o desempenho empresarial e é proposto um modelo que integra os fatores que têm influência sobre essa capacidade (estrutura, cultura, liderança, entorno e estratégia), os quais configuram promissoras linhas de pesquisa neste campo.

Objective. The objective of this study is to compare the effectiveness of intravenous enoxaparin (ENX) and Non-fractionated Heparin (NFH) in primary angioplasty (PA) of acute myocardial infarction (PA-AMI). Design. A prospective, observational study. Patients and methods. A total of 191 patients admitted at the hospital with the diagnosis of Acute Myocardial Infarction (AMI) and treated with primary angioplasty were included. ENX was used in 91 patients (47.6%) and NFH in 100 patients (52.4%). Choice of treatment was based on the operator's opinion. Patients with cardiogenic shock were excluded. The first group received an intravenous bolus of ENX (0.75-1 mg/Kg) and the second one NFH (70-100 u/Kg), depending on whether it was associated with abciximab or not. In-hospital follow-up was performed, evaluating mortality and bleeding complications of both treatments. Results. In-hospital mortality was 1.1% for the ENX group and 3.3% for NFH one. No significant differences were found in the number of bleeding complications with ENX (4.4%) and NFH (9.0%). There was one subacute thrombosis of stent for the ENX group and 3 thrombosis in the NFH-treated group. No significant differences were found in size of infarction measure with troponin I level (63.1 for ENX and 54.8 for the NFH) or in the left ventricle ejection fraction on hospital discharge (51% for ENX and 49.4% for the NFH). Conclusions. Primary angioplasty can be safely sued with the intravenous administration of ENX, no significant differences being found between both treatments in mortality and bleeding complications.

Objetivo. El objetivo de este estudio es comparar el efecto de la enoxaparina (ENX) y la heparina no fraccionada (HNF) intravenosas en la angioplastia primaria (AP) del infarto agudo de miocardio (IAMCEST). Diseño. Estudio prospectivo observacional. Pacientes y método. Se incluyó en el estudio a 191 pacientes con IAMCEST a los que se había realizado AP. En 91 (47,6%) se utilizó ENX y en 100 (52,4%), HNF. La elección del tratamiento se realizó a criterio del operador. Se excluyó a los pacientes con shock cardiogénico. Los pacientes recibieron un bolo intravenoso de ENX (0,75 o 1 mg/kg) o HNF (70 o 100 U/kg), dependiendo si se lo combinaba con abciximab o no. Se realizó seguimiento intrahospitalario evaluando la mortalidad y las complicaciones hemorrágicas de ambos tratamientos. Resultados. La mortalidad hospitalaria fue del 1,1% en el grupo ENX y del 3,3% en el grupo HNF (p = 0,359). Tampoco se encontraron diferencias significativas en el número de complicaciones hemorrágicas con ENX (4,4%) y con HNF (9%). Hubo 1 trombosis aguda o subaguda de stent con ENX y 3 con HNF. No se encontraron diferencias significativas en el tamaño del infarto medido con troponina I (63,1 con ENX y 54,8 con HNF) ni en la fracción de eyección del ventrículo izquierdo al alta hospitalaria (el 51% con ENX y el 49,4% con HNF). Conclusiones. La AP puede realizarse de forma segura con la administración intravenosa de ENX, pues no se ha encontrado diferencias significativas entre los dos tratamientos ni en mortalidad ni en complicaciones hemorrágicas.

This study explores the similarities between solid and liquid acid catalysts highlighting the advantages and the main challenges of heterogeneous catalytic processes. We describe the main developments in technical procedures like selection of compounds and reaction models involved in: increasing acidity, characterization of solid acidity and in coke formation.

The reduction kinetics of a CuO/ZnO/Al2O3 catalyst by hydrogen was investigated isothermally and by temperature programmed reduction (TPR). Two reducible Cu2+ species were detected; the first one was identified as CuO bulk and the other as Cu2+ strongly interacting with alumina, possibly in the form of copper aluminate. The activation energies for the reduction of these two species were 60 and 90 kJ mol-1, respectively, and the reaction order with respect to hydrogen was one. The isothermal reduction data showed that the isotropic growth model is the most appropriate to describe the reaction rate data for both Cu2+ species.

The effect of operational variables and their interaction in TPR profiles was studied using a fractional factorial experimental design. The heating rate and the reducing agent concentration were found to be the most important variables determining the resolution and sensitivity of the technique. They showed opposite effects. Therefore, they should be manipulated preferentially in order to obtain optimized TPR profiles. The effect of sample particle size was also investigated. The tests were carried out within a Cu/Zn/Al2O3 catalyst used for the water-gas shift reaction that presented two distinct species of Cu2+ in TPR profiles.