System Dynamics Simulation to Test Operational Policies in the Milk-Cheese Supply Chain Case study: Piar Municipality, Bolivar State, Venezuela.

With the purpose of detecting the impact that variations of demand cause in the milk-cheese supply chain, and determining how the operational policies of capacity, inventories or labor force can mitigate this impact, a system dynamics simulation model has been designed based on a survey conducted on a sample of cheese manufacturers and their links with milk farms, transportation companies and cheese distributors. This supply chain will be consolidated when a milk center that will collect the raw milk is completed. From this center, and after adequate treatment, milk will be distributed to the different cheese manufacturers in the supply chain. Managing adequately the milk-cheese supply chain represents an important challenge due to the short life of these products. Although this study was done in a region in Latin America, its results can be applicable to food supply chains by introducing some modifications. The milk-cheese supply chain in this case study contemplates three milk producers, one milk center, five cheese producers and several distributing agents. These companies operate individually under normal conditions, but they have understood that their integration in a supply chain improves the competitiveness of all its members. That is to say, the sum is greater than the parts. For its initial design a simulation software model is used in which the resources of the supply chain are optimized. Later the product of this optimization facilitates some initial values to be used in the system dynamics model in which causeeffect or influence relationships have been previously established considering the most representative variables. Finally, changes in operational policies that can reduce the level of pending orders in the supply chain are tested using other simulation software. The main contribution of this research is that it can serve as support or contribute to reduce the uncertainty in the decision making process of the supply chain management due to the speed with which individual or combined policies can be analyzed. In response to a variation of demand the most adequate policy may be selected and that can be done before the policy is implemented

Knowledge Management in Food Supply Chains

The object of the present article is to discuss Knowledge Management (KM) in the Agrifood Supply Chain (ASC). In the 21st century, the ASC is under strong tensions. This is evident in the drastic changes in the global scene. For example, in the year 2008, food prices were high and unstable. In the last years, the importance of knowledge as a source of competitive advantage for organizations has increased considerably, so it is necessary its management in the ASC in order to surpass the challenges of the 21st century. KM is a direction tool that focuses in determining, organizing, directing, providing and supervising the practices and activities related with the knowledge (intangible active) required to achieve the strategies and objectives of the business or industry, generating a value for the organization at the moment to reach capabilities and competences. In inter-organizational environments, KM is centered on horizontal alliances between two or more partners. However, there are few authors who have analyzed the vertical alliances between suppliers and customers (the supply chain). The existing KM models are applicable for the ASC, as long as a series of conditions are present in the same one. Among these conditions there is one which prevails: The different enterprises that integrate the ASC must coordinate themselves in order to constitute a dynamic network, in which learning barriers are eliminated, so knowledge can flow freely through them. In conclusion, the development of KM models in the ASC, in the framework of untimely, temporary and structural changes in the globalised world, represents a necessary tool to offer safety and quality food to the world-wide population in the 21st century. In this way, food markets will tend to become stabilized in the long term and adequate answers can be provided to the more vulnerable communities and region

Gestion del conocimiento en el sector agroalimentario

The objective of the article is to discourse about the management of the knowledge in the food chain. In the 21st century the food chain is being submitted to forts tense that can affect negatively its capacity to give the alimentary products to the whole world population. In this sense, the public opinion is increasingly sensible and the technical and legal procedures that govern the theme are more exigent in function to reach a food supply: sufficient, opportune, continuous and of quality to accessible costs, without prejudice of the health of the consumers and of the maintenance of the environment. This purpose could be reached if the knowledge is managed adequately, because this one has become into a source of competitive advantage for the organizations. The management of the knowledge is a tool of strategic direction of the practices and activities related to the knowledge (intangible actives) required to reach the objectives of the business or industry. Its application in the food industry will improve its levels of competitiveness and sustainability. Key words: food chain, management of the knowledg

Tecnologías de producción más limpias: una revisión del estado del arte

RESUMENEl planeta atraviesa por la más grave crisis ambiental de la historia, con manifestaciones evidentes en el aumento de temperatura incrementos en la temperatura del aire, los océanos, el aumento del nivel del mar, los deslizamientos de tierra, inundaciones e incendios son los efectos más visibles del cambio climático en el mundo.  En el presente trabajo se realiza una revisión de la literatura correspondiente a diferentes investigaciones realizadas, se encontró que las tecnologías de producción más limpias implementadas hasta ahora, han sido de gran ayuda mejorando la calidad de vida de muchos países. No obstante, también se tiene que tener en cuenta que a pesar de que la Producción Más Limpia (PML) se ha convertido en un fenómeno popular, esta no se ha implementado del todo porque el impacto que tiene la contaminación ambiental y el cambio climático, sumándole las materias toxicas y los gases de efecto invernadero sobre la tierra, es extenso. Por lo tanto, las medidas para controlar dichos enemigos de la humanidad van a pasos pequeños, pero seguro.ABSTRACTThe planet goes through the most serious environmental crisis in history, with obvious manifestations in the increase of temperature increases in air temperature, oceans, rising sea level, landslides, floods and fires are the most Climate change in the world. Through study of diverse investigations, it was found that the technologies implemented Cleaner Production (CP) so far have been of great help to improve the quality of life of many countries. However, it must also be borne in mind that although CP has become a popular phenomenon, this hasn’t been implemented at all because impact of environmental pollution and climate change, adding the toxic materials and greenhouse gases on earth is extensive. Therefore, measures to control these enemies of humanity are small steps, but safe

Antimicrobial activity of the fiber produced by “pochote” Ceiba aesculifolia subsp. parvifolia

Background: The cotton-like fiber from the fruit of Pochote (Ceiba aesculifolia subsp. parvifolia) can be applied to wounds for healing purposes. As microorganisms can infect wounds and hamper the wound healing process, the aim of this study was to determine the antimicrobial activity and chemical composition of the methanolic extract of Pochote fiber.Materials and Methods: The methanolic extract was tested against bacteria and fungi. For bacteria, the Kirby-Baüer disc diffusion and broth dilution methods were employed to determine the MIC and MBC. In addition, bactericidal kinetic curves were generated. The antifungal activity was determined by the radial diffusion method. The antioxidant activity, total phenolic content, and the flavonoid content were determined. Bioassay guided fractionation was also performed.Results: The methanolic extract showed activity against Enterococcus faecalis, Staphylococcus aureus and Vibrio cholerae (cc). The tested V. cholerae strains were the most sensitive strains, and exhibited a clear CFU size reduction from the bactericidal kinetic curves. The methanolic extract had activity against T. mentagrophytes and R. lilacina. The antioxidant activity (SC50= 36.42 μg/mL) was related to the total phenolic (74.4 mg eAG/g) and flavonoid content (21.982 mg (eQ)/g). The bioassay guided fractionation results suggested that the antimicrobial properties of the extract may act through synergism because the total extract had higher activity against bacteria compared to the collected fractions.Conclusion: This study scientifically validates the application of the fruit fiber from Pochote as a part of a traditional medicine approach to alleviate infections caused by bacteria and fungi.Keywords: antimicrobial, Ceiba, Bombacaceae, fruit fib

El ciclo del conocimiento en la producción de maíz (Zea mays L.)

El estudio tuvo por objeto caracterizar el ciclo del conocimiento en la producción de maíz (Zea mays L.). Venezuela tiene una importante producción de este rubro que forma parte de su dieta diaria. El conocimiento se crea, se almacena, se transfiere, se aplica y se preserva, en un ciclo que tiene la finalidad de incrementar la competitividad y sustentabilidad de las organizaciones. Se dise- ñó y aplicó una encuesta de 36 ítems a una muestra de 234 productores. El índice de conocimiento fue de 69,78% y el índice de percepción de resultados fue de 76,06%, encontrándose una relación positiva entre ambas variables. Se evidenció la ocurrencia del ciclo del conocimiento en cuatro etapas en las que interactuaron medios explícitos y tácito

Evaluation of cytotoxic and genotoxic effects with micronucleus test in the oral mucosa of patients with orthodontic appliances. Review of the literature

Las maloclusiones representan un problema de salud bucodental, que se resuelven mediante la colocación de aparatología ortodóncica fija (AOF). Esta aparatología provoca corrosión y liberación de iones metálicos por las aleaciones que la constituyen y por el tiempo prolongado del tratamiento. El objetivo de este trabajo fue analizar las alteraciones citotóxicas y genotóxicas de las células de la mucosa oral provocadas por el uso de AOF, reportadas en la literatura y evaluadas con ensayo de micronúcleos (MN); el cual es uno de los ensayos más utilizados para identificar el daño al ácido desoxirribonucleico (ADN). Se realizó una revisión de la literatura de los últimos 10 años, donde se incluyeron nueve estudios, el 55% de estos mostró evidencia de daño citotóxico y genotóxico posterior a la terapia ortodóncica. El promedio de incremento de MN debido al uso de AOF en estos estudios, fue tres veces mayor con respecto a las células bucales sin tratamiento, este dato es similar a reportes de células orales precancerosas investigadas por otros autores. Además los artículos evaluados, reportaron alteración celular a partir de la primera semana de la colocación de los dispositivos y señalaron que hay una disminución del daño con el tiempo de exposición. En conclusión, el ensayo de MN utilizado en la cavidad bucal demostró ser útil para detectar alteraciones en el ADN debido al uso de AOF. Los datos analizados permiten a los ortodoncistas implementar mejoras en la terapéutica ortodóncica.Malocclusions represent an oral health problem, which is resolved by the placement of fixed orthodontic appliances (FOA). This orthodontic appliance causes corrosion and release of metal ions due to the alloys they constitute and due to the prolonged time of treatment. The objective of this work was to analyze the cytotoxic and genotoxic alterations from oral mucosa cells, caused by the use of FOA, reported in the literature and evaluated with micronucleus (MN) test, which is one of the most widely used tests to identify damage to deoxyribonucleic acid (DNA). A review of the literature of the last 10 years was carried out, where nine studies were included, 55% of these studies showed evidence of cytotoxic and genotoxic damage after orthodontic therapy. The increased average in MN due to the use of FOA in these studies, represent values of approximately three-fold more respect to oral cells without treatment, this data is similar to reports of precancerous oral cells that have been reported by other authors. Besides, the articles analyzed reported cell alterations after the first week of the devices placement and indicated a decrease in damage with exposure time. In conclusion, the MN test used in the oral cavity was useful in detecting DNA alterations due to the use of FOA. The data analyzed allow orthodontists to implement improvements in orthodontic therapy

Hypoglycaemic and Antioxidant Effects of Propolis of Chihuahua in a Model of Experimental Diabetes

Propolis is a bee-collected natural product that has been proven to have various bioactivities. This study tested the effects of a Mexican propolis on streptozotocin-induced diabetes mellitus in a murine model. The results showed that an ethanolic extract of propolis of Chihuahua (EEPCh) significantly inhibited increases in blood glucose and the loss of body weight in diabetic mice. EEPCh increased plasma insulin levels in STZ-diabetic mice, whereas, in untreated diabetic mice, there was no detection of insulin. EEPCh had a high antioxidant capacity (SA50 = 15.75 μg/mL), which was directly related to the concentrations of total phenols (314 mg GAE/g of extract) and flavonoids (6.25 mg QE/g of extract). In addition, increased activities of the enzymes superoxide dismutase, catalase, and glutathione peroxidase were observed in diabetic mice treated with EEPCh. Compounds such as pinocembrin, quercetin, naringin, naringenin, kaempferol, acacetin, luteolin, and chrysin were identified by HPLC-MS analysis. This investigation demonstrated that propolis of Chihuahua possesses hypoglycaemic and antioxidant activities and can alleviate symptoms of diabetes mellitus in mice. These effects may be directly related to the chemical composition of propolis, as most of the compounds identified in propolis are reportedly active in terms of the different parameters evaluated in this work

Antimicrobial activity of Bursera morelensis ramírez essential oil

Background: Bursera morelensis, known as “Aceitillo”, is an endemic tree of Mexico. Infusions made from the bark of this species have been used for the treatment of skin infections and for their wound healing properties. In this work, we present the results of a phytochemical and antimicrobial investigation of the essential oil of B. morelensis.Materials and Methods: The essential oil was obtained by a steam distillation method and analyzed using GC-MS. The antibacterial and antifungal activities were evaluated.Results: GC-MS of the essential oil demonstrated the presence of 28 compounds. The principal compound of the essential oil was α-Phellandrene (32.69%). The essential oil had antibacterial activity against Gram positive and negative strains. The most sensitive strains were S. pneumoniae, V. cholerae (cc) and E. coli (MIC 0.125 mg/mL, MBC 0.25 mg/mL). The essential oil was bactericidal for V. cholera (cc). The essential oil inhibited all the filamentous fungi. F. monilifome (IC50 = 2.27 mg/mL) was the most sensitive fungal strain.Conclusions: This work provides evidence that confirms the antimicrobial activity of the B. morelensis essential oil and this is a scientific support about of traditional uses of this species.Keywords: Essential oil; Medicinal plants; Tehuacan-Cuicatlan Valley; Burseraceae; Burser

Síntesis y evaluación de Pd-Ru como electrocatalizador para la reacción de reducción de oxígeno

Se sintetizó el electrocatalizador Pd-Ru 1:1 por aleado mecánico de alta energía, obteniéndose a 30 horas de molienda, una aleación, caracterizada estructural y morfológicamente por difracción de rayos X y microscopía electrónica de barrido, observándose aglomerados de partículas con estructura lamelar, morfología irregular y cristalitas entre 4-10 nm. La actividad electrocatalítica del material hacia la reacción de reducción de oxígeno, se evaluó por la técnica de electrodo disco rotatorio en una solución 0.5 M de H₂SO₄, obteniéndose una transferencia multielectrónica global de 4e- para la formación de agua. Del análisis convencional de Tafel se determinó un orden de reacción de ∼1 y los parámetros cinéticos tales como, pendiente de Tafel de -108.8 mV dec-₁, coeficiente de actividad de 0.544 y corriente de intercambio de 1.05 x 10-₆ mA cm-₂. Por lo anterior, la aleación de Pd-Ru obtenida, puede ser una opción viable como electrocatalizador para el cátodo de una celda de combustible.Pd-Ru 1:1 electrocatalyst was synthesized by high energy mechanical alloying, obtaining an alloy at 30 hours of milling, characterized structural and morphological by X-ray diffraction and scanning electron microscopy, observing particles agglomerates with a lamellar structure, irregular morphology and crystallites between 4-10 nm. The electrocatalytic activity towards the oxygen reduction reaction was evaluated by the rotating disc electrode technique in a 0.5 M H₂SO₄, obtaining a global multielectronic transfer of 4e- for the water formation. From the Tafel analysis was determinate a reaction order of ∼1 and kinetic parameters such as, Tafel slope of -108.8 mV dec-₁, activity coefficient of 0.544 and exchange current of 1.05 x 10-6 mA cm- 2. So that the Pd-Ru alloy obtained, may be a viable option as an electrocatalyst for the cathode of fuel cells