58 research outputs found
Formas de integración cooperativa y sus principales técnicas de realización. La intercooperación cooperativa / Forms of Cooperative Integration and its Main Techniques of Realization. Cooperative Intercooperation
En el artÃculo son expuestas y valoradas las formas de integración cooperativa bajo el enfoque de cadenas y se presenta la intercooperación entre cooperativas como necesidad que facilite el desarrollo de las fuerzas productivas en el actual proceso de actualización del modelo económico en Cuba. Asimismo valora de muy positivo exponer estas experiencias de intercooperación que actualmente se desarrollan en Cuba, teniendo en cuenta su impacto más inmediato, en la gestión socioeconómica de las cooperativas implicadas y los territorios donde se desempeña.
In the article the forms of cooperative integration under the chain approach are exposed and valued and the intercooperation between cooperatives is presented as a necessity that facilitates the development of the productive forces in the current process of updating the economic model in Cuba. Likewise, it is very positive to present these experiences of intercooperation that are currently being developed in Cuba, taking into account its more immediate impact, in the socioeconomic management of the cooperatives involved and the territories where it operates
La Intercooperación entre Cooperativas AgrÃcolas /The Intercooperation between Agricultural Cooperatives
En el artÃculo son expuestos y valorados los antecedentes de la forma simple de cooperación entre cooperativa, lo cual dista en forma y contenido de la variante de intercooperación que se está desarrollando en el agro cubano, como experiencia en cuatro municipios del paÃs bajo el Proyecto APOCOOP. Ello constituye una expresión de los procesos de cambios y transformaciones que se están gestando en la actualización del modelo económico cubano y dan lugar a la búsqueda de formas superiores de organización.Â
In the article the background of the simple form of cooperative cooperation is exposed and valued, which is far from the form and content of the intercooperation variant that is being developed in Cuban agriculture, as an experience in four municipalities of the country under the APOCOOP Project. This constitutes an expression of the processes of changes and transformations that are taking place in the updating of the Cuban economic model and give rise to the search for superior forms of organization
Physicochemical and antimicrobial characterization of beeswax–starch food-grade nanoemulsions incorporating natural antimicrobials
Nanoemulsions are feasible delivery systems of lipophilic compounds, showing potential as edible coatings with enhanced functional properties. The aim of this work was to study the effect of emulsifier type (stearic acid (SA), Tween 80 (T80) or Tween 80/Span 60 (T80/S60)) and emulsification process (homogenization, ultrasound or microfluidization) on nanoemulsion formation based on oxidized corn starch, beeswax (BW) and natural antimicrobials (lauric arginate and natamycin). The response variables were physicochemical properties, rheological behavior, wettability and antimicrobial activity of BW–starch nanoemulsions (BW–SN). The BW–SN emulsified using T80 and microfluidized showed the lowest droplet size (77.6 ± 6.2 nm), a polydispersion index of 0.4 ± 0.0 and whiteness index (WI) of 31.8 ± 0.8. This BW–SN exhibited a more negative ζ-potential: −36 ± 4 mV, and Newtonian flow behavior, indicating great stability. BW–SN antimicrobial activity was not affected by microfluidization nor the presence of T80, showing inhibition of the deteriorative fungi R. stolonifer, C. gloeosporioides and B. cinerea, and the pathogenic bacterium S. Saintpaul. In addition, regardless of emulsifier type and emulsification process, BW–SN applied on the tomato surface exhibited low contact angles (38.5° to 48.6°), resulting in efficient wettability (−7.0 mN/m to −8.9 mN/m). These nanoemulsions may be useful to produce edible coatings to preserve fresh-produce quality and safety.We are grateful to CONACyT for PhD grant to Teresita Arredondo Ochoa, and financial support for project No. 166751. Special thanks are given to Alfonso Pérez for help on DSC analysis and Ma. Lourdes Palma Tirado for technical support on micrographs
Microencapsulation, Chemical Characterization, and Antimicrobial Activity of Mexican ( Lippia graveolens
The effect of solvent polarity (methanol and pentane) on the chemical composition of hydrodistilled essential oils (EO’s) of Lippia graveolens H.B.K. (MXO) and Origanum vulgare L. (EUO) was studied by GC-MS. Composition of modified starch microencapsulated EO’s was conducted by headspace-solid-phase microextraction (HS-SPME). The antimicrobial activity of free and microencapsulated EO’s was evaluated. They were tested against Salmonella sp., Brochothrix thermosphacta, Pseudomonas fragi, Lactobacillus plantarum, and Micrococcus luteus. Thymol and carvacrol were among the main components of EO’s and their free and microencapsulated inhibitory activity was tested against M. luteus, showing an additive combined effect. Chemical composition of EO’s varied according to the solvent used for GC analysis and to volatile fraction as evaluated by HS-SPME. Thymol (both solvents) was the main component in essential oil of MXO, while carvacrol was the main component of the volatile fraction. EUO showed α-pinene (methanol) and γ-terpinene (pentane) as major constituents, the latter being the main component of the volatile fraction. EO’s showed good stability after 3 months storage at 4°C, where antimicrobial activity of microencapsulated EO’s remained the same, while free EO’s decreased 41% (MXO) and 67% (EUO) from initial activity. Microencapsulation retains most antimicrobial activity and improves stability of EO’s from oregano
PROPUESTA DE UN ENTRENADOR MIOELÉCTRICO BASADO EN UNA APLICACIÓN MÓVIL
ResumenEn este artÃculo se desarrolló la propuesta de un entrenador mioeléctrico basado en una aplicación móvil. La importancia de este tipo de sistemas en el área de rehabilitación es su utilidad en la adaptación de un usuario para la manipulación de prótesis mioeléctricas. En particular la propuesta de este artÃculo está orientada a prótesis mioeléctricas de mano de un grado de libertad.El sistema utiliza la actividad eléctrica de los músculos o también llamada señal mioeléctrica, y mediante su procesamiento se obtiene la envolvente de la señal cuyo valor se utilizó como variable de control.Se consideró la importancia de este tema debido a que las señales electromiográficas de cada individuo pueden variar, ya que las fibras musculares de una persona pueden generar más energÃa que las de otra, y por lo tanto la necesidad para el usuario no debe depender de un estándar establecido. Se describirán las metodologÃas variadas, las estructuras de procesamiento de la señal, asà como el diagrama a bloques del circuito propuesto, los resultados y las conclusiones donde se discute la viabilidad del prototipo para su uso en el futuro en el área de rehabilitación y en el manejo de prótesis.Palabras Claves: ElectromiografÃa, envolvente, procesamiento de señales, servomotor. PROPOSAL OF A MIOELECTRIC TRAINER BASED ON A MOBILE APPLICATIONAbstractIn this article a proposal of a myoelectric trainer based on mobile application is presented. This kind of systems is useful in the rehabilitation of users of prosthetic devices. The trainers facilitate the use of myoelectric prostheses. In particular the proposed myoelectric trainer is oriented to hand prostheses with one degree of freedom. In the system developed the myoelectric signal recorded from upper limb muscles was used as source of information and the envelope obtained by means of signal processing was used as a control variable.The importance of this topic was considered because of the electromyographic signals of each individual can vary, since a person's muscle fibers can generate more energy than others, and therefore the need for the user should not depend on an established standard. The varied methodologies will be presented, the signal processing structures, as well as the block diagram of the proposed circuit, the results and the conclusion where it will be mentioned the viability of the prototype for its future use in the rehabilitation and handling of prostheses.Keywords: Electromyography, envelope, servomotor, signal processing
In vivo antimicrobial activity of silver nanoparticles produced via a green chemistry synthesis using Acacia rigidula as a reducing and capping agent
Introduction: One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells. Purpose: In this study, we report a green one-pot synthesis method that uses Acacia rigidula extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo. Materials and methods: The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet–visible, and Fourier transform infrared. Results: We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and a clinical multidrug-resistant strain of P. aeruginosa) and Gram-positive (Bacillus subtilis) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant P. aeruginosa clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models. Conclusion: Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains. Keywords: silver nanoparticles, green synthesis, in vitro antibacterial activity, in vivo antibacterial activity, skin infection, toxicological stud
Digging deeper into colonial palaeontological practices in modern day Mexico and Brazil
Scientific practices stemming from colonialism, whereby middle- and low-income countries supply data for high-income countries and the contributions of local expertise are devalued, are still prevalent today in the field of palaeontology. In response to these unjust practices, countries such as Mexico and Brazil adopted protective laws and regulations during the twentieth century to preserve their palaeontological heritage. However, scientific colonialism is still reflected in many publications describing fossil specimens recovered from these countries. Here, we present examples of ‘palaeontological colonialism’ from publications on Jurassic–Cretaceous fossils from NE Mexico and NE Brazil spanning the last three decades. Common issues that we identified in these publications are the absence of both fieldwork and export permit declarations and the lack of local experts among authorships. In Mexico, access to many fossil specimens is restricted on account of these specimens being housed in private collections, whereas a high number of studies on Brazilian fossils are based on specimens illegally reposited in foreign collections, particularly in Germany and Japan. Finally, we outline and discuss the wider academic and social impacts of these research practices, and propose exhaustive recommendations to scientists, journals, museums, research institutions and government and funding agencies in order to overcome these practices
Faunal evidence of the 1755 Lisbon Tsunami in Gibraltar (S Iberian Peninsula)
This paper analyzes the first systematic faunal record of the 1755 Lisbon tsunami in the Mediterranean.
On the basis of sedimentological and paleontological features, the sedimentary record of a core collected
in Gibraltar was divided into six sedimentary facies, with a paleoenvironmental evolution from a shallow
marine paleoenviroment to an increasingly restricted lagoon. This record includes a bioclastic layer
deposited by the 1755 Lisbon tsunami and characterized by an erosive base, presence of basal rip-up
clasts and abundant shell debris composed by marine and brackish molluscs. The paleoenvironmental
reconstruction derived from the foraminiferal analysis is congruent with that inferred from the sedimentary
and the macrofaunal reconstructions, with the introduction of brackish species into the innermost,
intertidal areas of a confined lagoon. This paleontological record is the first faunal evidence of the 1755
Lisbon tsunami in the Mediterranean.We thank the Gibraltar National Museum and its Director, Dr.
Clive Finlayson, for the efforts made to conserve and acquire the
BH borehole core. In addition, we thank the review of Dr. Akihisa
Kitamura and Dr. Briony Mamo, whose suggestions greatly
improved the manuscript, and the associate-editor of Geobios,
Dr. Frédéric Quillévéré, for his kind help and comments during
the revision process. This research was supported by two postdoctoral
fellows of the Spanish Ministry of Science and Innovation
Government (Subprograma JDCMICINN, JCI-2010-06160) and the
Huelva University (PP2010 P-01). Furthermore, this work is carried
out through DGYCIT project CTM2006-06722/MAR, DGYCIT project
CGL2006-01412, FEDER 2014-2020 project UHU-126029, PID2021-
127268NB-I00 project funded by MCIN/ AEI /10.13039/50110
0011033/ and by FEDER, and AYUDA PUENTE 2021 project
M2615 of the Rey Juan Carlos University. Other funds have come
from the Andalusian Government (groups RNM-238, RNM-293
and RNM-349) and Autonomous University of Madrid (GPG-418
Research Group). It is a contribution to the Research Center in Historical,
Cultural and Natural Heritage (CIPHCN) of the University of
Huelva
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