El control de los criterios de higiene de los procesos en mataderos de cerdo ibérico como medio para evaluar el funcionamiento aceptable de la producción

La normativa vigente obliga a los mataderos de cerdo ibérico a desarrollar e implantar un plan APPCC (Análisis de Peligros y Puntos de Control Crítico). De igual modo deben comprobar el correcto funcionamiento de su proceso de producción realizando controles microbiologícos de la superficie de las canales, siguiendo un plan de muestreo diseñado de acuerdo al Reglamento 2073/2005. En el presente trabajo se expone el diseño de un plan de muestreo de un matadero de cerdo ibérico, y se muestran los resultados obtenidos en los primeros controles realizados siguiendo dicho plan

Controles analíticos realizados en una pequeña industria elaboradora de quesos de oveja y su papel en el contexto de la garantía de inocuidad de los productos elaborados

Como parte de las actuaciones encaminadas a asegurar la inocuidad de los quesos, las industrias elaboradoras de quesos deben comprobar la ausencia de antibióticos en la leche que utilizan como materia prima, así como la calidad microbiológica de ésta. Igualmente deben llevar a cabo controles microbiológicos de los quesos que ponen en el mercado. El presente trabajo muestra el modo en que lleva a cabo estos controles una industria elaboradora de queso de oveja, así como la comparación de los resultados obtenidos en los mencionados controles durante el año 2006 con los criterios establecidos en la normativa vigente

Correlation between Mn oxidation state and magnetic behavior in Mn/ZnO multilayers prepared by sputtering

Compositional, microstructural, and magnetic characterization of ZnO 30 Å/Mn x n multilayers prepared by sputtering is presented to study the observed ferromagnetism in the Mn-ZnO system. The nominal Mn layer thickness, x, is varied from 3 to 60 Å, while the number of bilayers, n, is increased to maintain the total amount of Mn constant. Microstructure information was deduced from x-ray reflectivity, Mn oxidation state was determined by x-ray absorption spectroscopy, and magnetic properties were measured over a temperature range of 5–400 K. Magnetic behavior of these samples is found to be related to the Mn layer thickness x. Multilayers with x 30 Å exhibit ferromagnetism with a Curie temperature above 400 K, while mostly paramagnetic behavior is obtained for x15 Å. Magnetic behavior is discussed in terms of electronic and structural parameters of samples. Mn-ZnO interface effect is related to the ferromagnetic order of the samples, but it is not a sufficient condition. The essential role of the Mn oxidation state in the magnetic behavior of this system is pointed out. It is shown a correlation between the obtained ferromagnetism and a Mn oxidation state close to 2+.Ministerio de Educación y Ciencias de España-MAT2003-01880 y MAT2006-0100

Controlling the transmission at the surface plasmon resonance of nanocomposite films using photonic structures

3 pages, 3 figures, 1table.The transmission of nanocomposite thin films formed by Cu nanocrystals embedded in an amorphous aluminum oxide (Al2O3) matrix has been enhanced in the vicinity of the surface plasmon resonance wavelength, by the design of one-dimensional photonic structures. The nanocrystals are distributed in layers, whose separation and periodicity are used to control the optical response of the films. It is found that at the SPR a transmission enhancement up to 36% can be achieved with respect to a film with an homogeneous distribution of the nanocrystals. These photonic structures have been successfully produced by pulsed laser deposition.D. E. Hole is acknowledged for performing RBS measurements. This work has been supported by Project No. TIC2002-03235, CICYT (Spain).Peer reviewe

Induced ferromagnetism in Mn3N2 phase embedded in Mn/Si3N4 multilayers

Room temperature ferromagnetism has been obtained for different sets of Mn/Si3N4 multilayers prepared by sputtering. In order to find the most suitable conditions to stabilize the ferromagnetic ordering in this system, the evolution of the magnetic properties has been studied for films in which the Si3N4 layer thickness was maintained constant while that of the Mn layer was varied, Mn tm/Si3N4 3.4 nm n, and conversely, in Mn 0.7 nm/Si3N4 tsn 43 samples, in which the Mn layer thickness was kept constant while varying the Si3N4 layer thickness. Structural, compositional, electronic and magnetic characterizations have been performed by means of x-ray reflectometry, Rutherford backscattering spectrometry, x-ray photoemission spectroscopy, x-ray absorption, and superconducting quantum interference device for further knowledge of the magnetic-structural relationship in this system. Our results show that the peculiar magnetic behavior of these films is mainly related to the stabilization of a slightly distorted Mn3N2 phase that is induced by the Si3N4 at the interfaces. For samples with larger Mn layer thickness, metallic Mn and Mn3N2 phases coexist, which leads to a reduction of the total magnetization per Mn atom due to the presence of metallic Mn. For small Mn layer thickness tm 0.86 nm, where noncontinuous Mn3N2 layers are formed, the magnetization decreases noticeably due to the superparamagnetic size limit. It has been found that the best conditions for the stabilization of the ferromagnetism in this system occur when both, the manganese-rich and the silicon nitride layers, are continuous and with similar thickness, close to 3.5 nm.Ministerio de Educación y Ciencia de España-MAT2006-01004, MAT2008-06542-C04-01, MAT2008-06765-C02-02, S-0505/MAT/0194, Consolider 2010_26400 y Nanoselect CSD2007-0004

QUALITY OF SERVICE OF SMALL HARDWARE COMPANIES IN A NORTHERN PERUVIAN PROVINCE

Currently, the quality of service provided by companies plays a fundamental role as a strategy to meet customer expectations and achieve customer satisfaction. The objective of the study was to identify the customers' perception of the quality of service provided by companies in the hardware sector in the province of Tumbes. In the methodology, the approach was quantitative, descriptive level and non-experimental design. The sample consisted of 487 clients of 10 companies that sell construction products. A questionnaire was adapted as a data collection instrument to evaluate the quality of service in a service company. The results showed that high levels of service quality prevailed with 72.48%, followed by medium with 25.87% and low with 1.64%. High levels of service quality were also found according to the sociodemographic variables sex, age and marital status. It is concluded that the majority of the clients considered the quality of service of the small hardware companies to be high, while only a small percentage considered the quality of service to be low

The tumour suppressor and chromatin-remodelling factor BRG1 antagonizes Myc activity and promotes cell differentiation in human cancer

BRG1, a member of the SWI/SNF complex, is mutated in cancer, but it is unclear how it promotes tumourigenesis. We report that re-expression of BRG1 in lung cancer cells up-regulates lung-specific transcripts, restoring the gene expression signature of normal lung. Using cell lines from several cancer types we found that those lacking BRG1 do not respond to retinoic acid (RA) or glucocorticoids (GC), while restoration of BRG1 restores sensitivity. Conversely, in SH-SY5Y cells, a paradigm of RA-dependent differentiation, abrogation of BRG1 prevented the response to RA. Further, our data suggest an antagonistic functional connection between BRG1 and MYC, whereby, refractoriness to RA and GC by BRG1 inactivation involves deregulation of MYC activity. Mechanistically, some of these effects are mediated by BRG1 binding to MYC and MYC-target promoters. The BRG1-MYC antagonism was also evident in primary tumours. Finally, BRG1 restoration significantly dampened invasion and progression and decreased MYC in lung cancer cells orthotopically implanted in nude mice. Thus, BRG1 inactivation enables cancer cells to sustain undifferentiated gene expression programs and prevent its response to environmental stimuli

Leishmania spp. epidemiology of canine leishmaniasis in the Yucatan Peninsula

Canine Leishmaniasis is widespread in various Mexican states, where different species of Leishmania have been isolated from dogs. In the present study, we describe the detection of L. braziliensis, L. infantum, and L. mexicana in serum of dogs from the states of Yucatan and Quintana Roo in the Yucatan Peninsula (Mexico). A total of 412 sera were analyzed by ELISA using the total extract of the parasite and the iron superoxide dismutase excreted by different trypanosomatids as antigens. We found the prevalence of L. braziliensis to be 7.52%, L. infantum to be 6.07%, and L. mexicana to be 20.63%, in the dog population studied. The results obtained with ELISA using iron superoxide dismutase as the antigen were confirmed by western blot analysis with its greater sensitivity, and the agreement between the two techniques was very high