RELATORÍA: EL QUEHACER DE LOS LABORATORIOS DEL SERVICIO NACIONAL DE SANIDAD, INOCUIDAD Y CALIDAD AGROALIMENTARIA (SENASICA)

Debido a grandes brotes de enfermedades en animales o plagas que han afectado a México, desde principios del siglo veinte surge la necesidad de crear sistemas de análisis sofisticados en los laboratorios con la finalidad de crear protocolos de diagnóstico, fichas técnicas, manuales y catálogos, así como detectar patógenos, plagas y malezas. El Servicio Nacional de Sanidad, Inocuidad y Calidad Agroalimentaria (SENASICA) dependiente de la SAGARPA, tiene la misión de regular, administrar y fomentar las actividades de sanidad, inocuidad y calidad agroalimentaria, reduciendo los riesgos inherentes en materia agrícola, pecuaria, acuícola y pesquera en beneficio de los productores, consumidores e industria; cuenta con una red de laboratorios que atiende la detección de plagas y enfermedades que ponen en riesgo la viabilidad económica del sector agropecuario acuícola, pesquero y de salud pública

Source apportionment of PM10 in the Western Mediterranean based on observations from a cruise ship

Abstract Two intensive PM10 sampling campaigns were performed in the summers of 2009 and 2010 on the ship Costa Pacifica during cruises in the Western Mediterranean. Samples, mainly collected on an hourly basis, were analysed with different techniques (Particle Induced X-Ray Emission, PIXE; Energy Dispersive - X Ray Fluorescence, ED-XRF; Ion Chromatography, IC; Thermo-optical analysis) to retrieve the PM10 composition and its time pattern. The data were used for obtaining information about the sources of aerosol, with a focus on ship emissions, through apportionment using chemical marker compounds, correlation analysis and Positive Matrix Factorization (PMF) receptor modelling. For the campaign in 2010, 66% of the aerosol sulphate was found to be anthropogenic, only minor contributions of dust and sea salt sulphate were observed while the biogenic contribution, estimated based on the measurements of MSA, was found to be more important (26%), but influenced by large uncertainties. V and Ni were found to be suitable tracers of ship emissions during the campaigns. Four sources of aerosol were resolved by the PMF analysis; the source having the largest impact on PM10, BC and sulphate was identified as a mixed source, comprising emissions from ships. The correlations between sulphate and V and Ni showed the influence of ship emissions on sulphate in marine air masses. For the leg Palma–Tunis crossing a main ship route, the correlations between aerosol sulphate and V and Ni were particularly strong (r2 = 0.9 for both elements)

RNase H activities counteract a toxic effect of Polymerase in cells replicating with depleted dNTP pools

RNA:DNA hybrids are transient physiological intermediates that arise during several cellular processes such as DNA replication. In pathological situations, they may stably accumulate and pose a threat to genome integrity. Cellular RNase H activities process these structures to restore the correct DNA:DNA sequence. Yeast cells lacking RNase H are negatively affected by depletion of deoxyribonucleotide pools necessary for DNA replication. Here we show that the translesion synthesis DNA polymerase (Pol ) plays a role in DNA replication under low deoxyribonucleotides condition triggered by hydroxyurea. In particular, the catalytic reaction performed by Pol is detrimental for RNase H deficient cells, causing DNA damage checkpoint activation and G2/M arrest. Moreover, a Pol mutant allele with enhanced ribonucleotide incorporation further exacerbates the sensitivity to hydroxyurea of cells lacking RNase H activities. Our data are compatible with a model in which Pol activity facilitates the formation or stabilization of RNA:DNA hybrids at stalled replication forks. However, in a scenario where RNase H activity fails to restore DNA, these hybrids become highly toxic for cells

Calibración de los parámetros del modelo de directividad de los transductores de la ecosonda Simrad EK60

The scientific echo sounder Simrad EK60 could be used for quantification of fisheries resources in marine science research campaigns. They use different frequency channels (from 18 to 200 KHz), emitted by underwater sound transducers with circular aperture geometries. Calibration is essential to obtain reliable values of Ts (Target Strength) and Sv (Volume Backscattering Coefficient) parameters, which are used to estimate fisheries stocks using echo volume integration. In this paper, manufacturer’s calibration method is presented, together a new proposal for the acquisition and post-processing of calibration data to obtain more accurate results.La ecosonda científica Simrad EK60 se utiliza para cuantificar los recursos pesqueros en campañas de investigación oceanográfica, utilizando diferentes canales de frecuencias (de 18 a 200KHz) mediante transductores acústicos de apertura con geometría circular. Su calibración resulta esencial para obtener los valores de Ts (‘target strength’) y Sv (‘Volume backscattering coefficient’), necesarios para estimar los tamaños de los stocks de las pesquerías mediante integración de los ecos. En este trabajo se presenta el método de calibración propuesto por el fabricante, así como una nueva propuesta de obtención y postproceso de datos que permite obtener calibraciones fiable

Image analysis to identify objects in filters obtained from turbidity plumes

The study of turbidity plumes developed in front of the river mouth, have an increasing scientific interest due to its contribution to infralittoral sediment transport and deposition. River plume evolution and deposition in submarine fans related to environmental constrains could be interpreted by the analysis of suspended particulate matter (SPM) retained during the filtering process. In this study, a new methodology approach to obtain quantitative results in sediment filters, using custom digital image processing techniques, is presented and some promising preliminary results are obtained. This procedure could avoid time-consuming during SPM analysis allowing an easy way to obtain fast and quantitative information, which might lead to a better interpretation and comprehension of factors involved in the evolution of riverine turbidity plumes.Versión del edito

A new methodology to assess the performance and uncertainty of source apportionment models II: The results of two European intercomparison exercises

The performance and the uncertainty of receptor models (RMs) were assessed in intercomparison exercises employing real-world and synthetic input datasets. To that end, the results obtained by different practitioners using ten different RMs were compared with a reference. In order to explain the differences in the performances and uncertainties of the different approaches, the apportioned mass, the number of sources, the chemical profiles, the contribution-to-species and the time trends of the sources were all evaluated using the methodology described in Belis et al. (2015). In this study, 87% of the 344 source contribution estimates (SCEs) reported by participants in 47 different source apportionment model results met the 50% standard uncertainty quality objective established for the performance test. In addition, 68% of the SCE uncertainties reported in the results were coherent with the analytical uncertainties in the input data. The most used models, EPA-PMF v.3, PMF2 and EPA-CMB 8.2, presented quite satisfactory performances in the estimation of SCEs while unconstrained models, that do not account for the uncertainty in the input data (e.g. APCS and FA-MLRA), showed below average performance. Sources with well-defined chemical profiles and seasonal time trends, that make appreciable contributions (>10%), were those better quantified by the models while those with contributions to the PM mass close to 1% represented a challenge. The results of the assessment indicate that RMs are capable of estimating the contribution of the major pollution source categories over a given time window with a level of accuracy that is in line with the needs of air quality management