Búsqueda avanzada


Área de conocimiento




6910 resultados, página 10 de 10

Como las redes sociales contribuyen al conocimiento de la sistemática de plantas

RODRIGO STEFANO DUNO GERMAN CARNEVALI FERNANDEZ CONCHA (2022, [Artículo])

La ciencia y la sistemática, en particular, se han beneficiado enormemente de la tecnología. Pregúntele a cualquier amante de la naturaleza y de la fotografía, el cambio que significó la llegada de las cámaras digitales en sustitución de las cámaras convencionales. Hoy deseamos destacar otra novedad tecnológica, no menos tangible, y de enorme repercusión mundial; las redes sociales. En este breve texto presentaremos casos concretos de cómo las redes sociales pueden ser una herramienta fundamental para incrementar el conocimiento de la diversidad biológica.

APOCYNACEAE DROSERACEAE FACEBOOK NATURALISTA NOVEDADES TAXONOMICAS REDES SOCIALES BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA VEGETAL (BOTÁNICA) ECOLOGÍA VEGETAL ECOLOGÍA VEGETAL

Shopping centers at zmcm. The companies, location and production of a neoliberal urban space

Dante-Guillermo Celis-Galindo (2021, [Artículo, Artículo])

This work aims to analyze different aspects of shopping center at the Metropolitan Zone of Mexico City as location, opening year and developer company. Also it will identify diverse characteristics, economic and political phases in the country as well as the role of the development companies and shopping centers as a producers of a neoliberal urban space. This paper presents the way shopping centers importance has growth and how it had become in a neoliberal city characteristic; with this the characteristics of these urban works are visualized and related with their construction companies and local governments which has caused the transformation of the city. After conducting a census, with more than two hundred shopping centers, the study was delimited to those with the greatest significance by size, location and developer. At the beginning of the paper, the characteristics that shopping malls should have for the realization of this work are mentioned. In a first section an approach is made to the theoretical elements of the city and the shopping center and therefore identifying the developers that most  nfluence this process; the second section addresses the characteristics of places by location and the characteristics that urban planners have depending on the area where they are; the third section discusses the years of opening, the squares and relates to government administrations and the economic characteristics of the country; and finally, a tour of the urban regulations in Mexico City and its latest modifications is made.

shopping center neoliberalism space urban space construction company centro comercial neoliberalismo espacio espacio urbano empresa constructora HUMANIDADES Y CIENCIAS DE LA CONDUCTA HUMANIDADES Y CIENCIAS DE LA CONDUCTA

Approaches in Polymeric Nanoparticles for Vaginal Drug Delivery: A Review of the State of the Art

GERARDO LEYVA GOMEZ ELIZABETH PIÑON SEGUNDO NESTOR MENDOZA MUÑOZ MARIA DE LA LUZ ZAMBRANO ZARAGOZA SUSANA ELISA MENDOZA ELVIRA DAVID QUINTANAR GUERRERO (2018, [Artículo])

The vagina is a region of administration with a high contact surface to obtain local or systemic effects. This anatomical area represents special interest for government health systems for different sexually transmitted infections. However, the chemical changes of the vagina, as well as its abundant mucus in continuous exchange, act as a barrier and a challenge for the development of new drugs. For these purposes, the development of new pharmaceutical forms based on nanoparticles has been shown to offer various advantages, such as bioadhesion, easy penetration of the mucosa, and controlled release, in addition to decreasing the adverse effects of conventional pharmaceutical forms. In order to obtain nanoparticles for vaginal administration, the use of polymers of natural and synthetic origin including biodegradable and non-biodegradable systems have gained great interest both in nanospheres and in nanocapsules. The main aim of this review is to provide an overview of the development of nanotechnology for vaginal drug release, analyzing the different compositions of polymeric nanoparticles, and emphasizing new trends in each of the sections presented. At the end of this review, a section analyzes the properties of the vehicles employed for the administration of nanoparticles and discusses how to take advantage of the properties that they offer. This review aims to be a reference guide for new formulators interested in the vaginal route.

MEDICINA Y CIENCIAS DE LA SALUD Vagina nanoparticles

Drought vulnerability indices in Mexico

David Ortega Gaucin JESUS DE LA CRUZ BARTOLON HEIDY VIVIANA CASTELLANO BAHENA (2018, [Artículo])

Drought is one of the most harmful hydro climatic threats to society. Mexico has been historically affected by recurring and long-lasting droughts that have severely impacted society and the economy. Consequently, public programs and policies have been developed in order to reduce the country’s vulnerability to drought, hence the importance of identifying the spatial distribution and the dimension—even in relative terms only—of vulnerability in different regions from social, economic, and environmental perspectives. This article presents a method for obtaining indices and maps of vulnerability to drought in Mexico; indices and maps are based on a set of socioeconomic and environmental indicators that the method combines using an objective analytic procedure that identifies the most vulnerable states and municipalities from social, economic, and environmental perspectives, all of which converge in overall vulnerability to drought. The results obtained indicate that 38.9% of total Mexican population inhabits municipalities with high and very high degrees of overall vulnerability to drought. For this reason, it is necessary to continue implementing actions and preventive and mitigation strategies via public policies and social programs aimed at decreasing the country’s vulnerability to the occurrence of drought events. This is the only way to facilitate the necessary conditions to reduce the impact of drought and to decrease people’s vulnerability to this phenomenon.

Sequías Desastres naturales Gestión de riesgos Vulnerabilidad CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

Optimization of the alkali-silane treatment of agave lechuguilla fibers (ixtle) for potential reinforcement in polymeric composites

NOEMI JARDON MAXIMINO MARIAMNE DEHONOR GOMEZ Rolando Villa Moreno MARIA DOLORES BAEZA ALVARADO Luis Edmundo Lugo Uribe (2023, [Artículo])

Reinforced polymeric composites with natural fibers have garnered significant interest in recent years due to the need for biomass utilization and the requirements of various industries, such as automotive and construction. Among these natural fibers, Agave lechuguilla fiber, commonly known as ixtle (FIx) or Tampico fiber, exhibits important characteristics such as length, high strength, and durability. However, there is limited literature on its conditioning, functionalization, and utilization as a reinforcing material in polymeric composites (CP). This study presents the optimization of the alkali-silane treatment of FIx, identifying the most suitable reaction conditions to enhance their thermal stability, tensile strength, and silane coupling agent (ACSi) grafting on the fiber surface. The chemical treatment with ACSi proved highly effective, resulting in a significant grafting content, which was confirmed through FTIR and SEM–EDS analyses. The high level of functionalization did not compromise the mechanical performance of the fibers, suggesting that functionalized FIx holds great potential as a reinforcing material in CP. These findings open new paths for the sustainable use of Agave lechuguilla fibers, contributing to the development of environmentally friendly and high-performance polymeric composites in various industrial applications.

This article belongs to the Special Issue Natural Fibers for Advanced Materials: Addressing Challenges).

Supplementary materials: The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/fib11100086/s1, Figure S1: Optical microscope image of ixtle fibers at a magnification of 50 (a) untreated and (b) alkaline treated (FIx-5); Table S1: FTIR signal assignment for alkaline treated FIx; Table S2: FTIR Signal assignment for silane treated FIx.

Author contributions: Conceptualization, N.J.-M. and L.E.L.U.; methodology, N.J.-M., M.D.G., R.V.M., M.D.B.-A. and L.E.L.U.; validation, N.J.-M. and L.E.L.U.; formal analysis, N.J.-M., M.D.G. and L.E.L.U.; investigation, N.J.-M. and L.E.L.U.; data curation, N.J.-M., M.D.G., R.V.M. and M.D.B.-A.; writing—original draft preparation, N.J.-M. and L.E.L.U.; writing—review and editing, N.J.-M., M.D.G., R.V.M., M.D.B.-A. and L.E.L.U.; visualization, N.J.-M., M.D.G. and L.E.L.U.; supervision, L.E.L.U.; project administration, N.J.-M. and L.E.L.U.; funding acquisition, N.J.-M. and L.E.L.U. All authors have read and agreed to the published version of the manuscript.

Funding: This research was funded by CONAHCYT, “Estancias postdoctorales por México”, grant umber CVU425480.

Data availability statement: Data supporting the findings of this study are available within the article and upon request from the corresponding author.

Acknowledgments: The authors express their gratitude towards Rene Diaz Rebollar and Jazmin Gomez Sara for their technical assistance in conducting the chemical reactions presented in this current study. Additionally, the assistance provided by Luis Alberto Caceres Diaz in the execution of XRD analyses is also acknowledged. Furthermore, N.J.M. extends sincere recognition to CIATEQ A.C. for their provision of essential resources and infrastructure crucial to the advancement of this research. The support rendered by CONAHCYT through the “Estancias postdoctorales por México” program is also gratefully acknowledged, as it has contributed financial backing to the project. Conflicts of Interest: The authors declare no conflict of interest.

Agave lechuguilla Natural fiber Silane coupling agent INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS OTRAS ESPECIALIDADES TECNOLÓGICAS OTRAS OTRAS

Women, economic resilience, gender norms in a time of climate change: what do we know?

Cathy Farnworth Anne Rietveld Rachel Voss Angela Meentzen (2023, [Artículo])

This literature delves into 82 research articles, published between 2016 and 2022, to develop a deep understanding of how women manage their lives and livelihoods within their agrifood systems when these systems are being affected, sometimes devastatingly, by climate change. The Findings show that four core gender norms affect the ability of women to achieve economic resilience in the face of climate change operate in agrifood production systems. Each of these gender norms speaks to male privilege: (i) Men are primary decision-makers, (ii) Men are breadwinners, (iii) Men control assets, and (iv) Men are food system actors. These gender norms are widely held and challenge women’s abilities to become economically resilient. These norms are made more powerful still because they fuse with each other and act on multiple levels, and they serve to support other norms which limit women’s scope to act. It is particularly noteworthy that many institutional actors, ranging from community decision-makers to development partners, tend to reinforce rather than challenge gender norms because they do not critically review their own assumptions.

However, the four gender norms cited are not hegemonic. First, there is limited and intriguing evidence that intersectional identities can influence women’s resilience in significant ways. Second, gender norms governing women’s roles and power in agrifood systems are changing in response to climate change and other forces, with implications for how women respond to future climate shocks. Third, paying attention to local realities is important – behaviours do not necessarily substantiate local norms. Fourth, women experience strong support from other women in savings groups, religious organisations, reciprocal labour, and others. Fifth, critical moments, such as climate disasters, offer potentially pivotal moments of change which could permit women unusually high levels of agency to overcome restrictive gender norms without being negatively sanctioned. The article concludes with recommendations for further research.

Economic Resilience Intersectional Identities Women Groups Support CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA ECONOMICS RESILIENCE CLIMATE CHANGE GENDER NORMS AGRIFOOD SYSTEMS WOMEN