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Logical analysis of sample pooling for qualitative analytical testing
Get PDFWhen the prevalence of positive samples in a whole population is low, the pooling of samples to detect them has been widely used for epidemic control. However, its usefulness for applying analytical screening procedures in food safety (microbiological or allergen control), fraud detection or environmental monitoring is also evident.
The expected number of tests per individual sample that is necessary to identify all ‘positives’ is a measure of the efficiency of a sample pooling strategy. Reducing this figure is key to an effective use of available resources in environmental control and food safety. This reduction becomes critical when the availability of analytical tests is limited, as the SARS-CoV-2 pandemic showed.
The outcome of the qualitative analytical test is binary. Therefore, the operation governing the outcome of the pooled samples is not an algebraic sum of the individual results but the logical operator
(‘or’ in natural language). Consequently, the problem of using pooled samples to identify positive samples naturally leads to proposing a system of logical equations. Therefore, this work suggests a new strategy of sample pooling based on: i) A half-fraction of a Placket-Burman design to make the pooled samples and ii) The logical resolution, not numerical, to identify the positive samples from the outcomes of the analysis of the pooled samples.
For a prevalence of ‘positive’ equal to 0.05 and 10 original samples to be pooled, the algorithm presented here results in an expected value per individual equal to 0.37, meaning a 63% reduction in the expected number of tests per individual sample.
With sensitivities and specificities of the analytical test ranging from 0.90 to 0.99, the expected number of tests per individual ranges from 0.332 to 0.416, always higher than other pooled testing algorithms. In addition, the accuracy of the algorithm proposed is better or similar to that of other published algorithms, with an expected number of hits ranging from 99.16 to 99.90%.
The procedure is applied to the detection of food samples contaminated with a pathogen (Listeria monocytogenes) and others contaminated with an allergen (Pistachio) by means of Polymerase Chain Reaction, PCR, test.This work was supported by Consejería de Educación de la Junta de Castilla y León through project BU052P20 co-financed with European Regional Development Funds. The authors thank Dr. Laura Rubio for applying the double-blind protocol to dope the samples and AGROLAB S.L.U, Burgos (Spain) for the careful preparation of the pooled samples
Cuéntame y yo escribo tu historia: biografías de nuestro pasado reciente narradas por las futuras generaciones
No full textLas personas mayores son fuentes vivas de nuestra historia más reciente, han vivido de primera mano hechos históricos importantes, se han criado de un modo muy distinto al de nuestros días, han pasado por situaciones que pueden parecen increíbles, conocen tradiciones que poco a poco van desapareciendo...
Este libro recoge las vivencias de un grupo de personas mayores, hombres y mujeres con o sin estudios, de diferente clase social, procedentes del medio rural o el urbano y con una historia que contar.
Las historias han sido escritas por estudiantes de la Universidad de Burgos, quienes han querido dignificar a las personas mayores poniendo en valor las vivencias de algunas de ellas.
Este libro es un homenaje a todas esas personas que nos han precedido y a las que nunca debemos olvidar. Todas ellas tienen una historia que merece la pena ser contada
Semi-supervised classification with pairwise constraints: A case study on animal identification from video
Get PDFMainstream semi-supervised classification assumes that part of the available data are labelled. Here we assume that, in addition to the labels, we have pairwise constraints on the unlabelled data. Each constraint links two instances, and is one of Must Link (ML, belong to the same class) or Cannot Link (CL, belong to different classes). We propose an approach that uses the labelled data to train a classifier and then applies the ML and CL constraints in subsequent labelling. In our approach, a set of instances are labelled at the same time. Our case study is on animal re-identification. The dataset consists of five free-camera video clips of animals (koi fish, pigeons and pigs), annotated with bounding boxes and animal identities. The proposed approach combines the representations or classifiers predictions from the bounding boxes of consecutive frames. We demonstrate that our approach outperforms standard classifiers, constrained clustering, as well as inductive and transductive semi-supervised learning, using five feature representations.This work is supported by the UKRI Centre for Doctoral Training in Artificial Intelligence, Machine Learning and Advanced Computing (AIMLAC), funded by grant EP/S023992/1. This work is also supported by the Junta de Castilla León under project BU055P20 (JCyL/FEDER, UE), and the Ministry of Science and Innovation of Spain under the projects PID2020-119894GB-I00/AEI/10.13039/501100011033, co-financed through European Union FEDER funds. J.L. Garrido-Labrador is supported through Consejería de Educación of the Junta de Castilla y León and the European Social Fund through a pre-doctoral grant (EDU/875/2021). I. Ramos-Perez is supported by the predoctoral grant (BDNS 510149) awarded by the Universidad de Burgos, Spain. J.J. Rodríguez was supported by mobility grant PRX21/00638 of the Spanish Ministry of Universities
Recent Trends in Enzyme-Based Electrosensing Devices Modified with Nanomaterials
No full textEnzyme-based electrochemical biosensors are analytical devices with great potential in various fields, thanks to their specificity, high sensitivity, and the possibility of automation and miniaturization. The analytical performance of these electrochemical devices can be remarkably improved by the employing of advanced nanomaterials due to the important features of these materials, including great effectiveness in electron transfer related to its high surface area and conductivity. This chapter reports the recent applications of different enzymatic biosensors based on the modification of the working electrode with nanomaterials, including fullerenes, graphene, carbon nanotubes (CNTs), carbon and graphene quantum dots (QDs), metallic nanoparticles (NPs), and inorganic QDs. The reported devices are categorized according to the target biomolecule, and their description has considered not only the nanomaterial used but also the type of electronic transfer that takes place (direct or mediated) as well as the enzymatic mechanism involved
The importance of social interactions in the expansion of romanesque galleries at "Sierra de la Demanda" (Burgos y La Rioja)
Get PDFEntre las últimas décadas del siglo XII y las primeras del XIII los pórticos románicos aparecieron en las estribaciones occidentales del Sistema Ibérico conocidas como sierra de la Demanda. Allí la nueva tipología arraigó rápidamente y llegaron a levantarse varias construcciones, de las cuales hemos conservado, al menos con ciertas evidencias materiales, once de ellas. El presente trabajo tiene como objetivo establecer una secuencia cronológica sobre la llegada y expansión de esa tipología arquitectónica al territorio, analizando las circunstancias sociales que permitieron el desarrollo de dicho proceso.Between the last decades of the 12th century and the first decades of the 13th century, Romanesque porchs began to appear in the “Sierra de la Demanda” (North of Spain). The new typology was successful and we conserve eleven porchs, all wich constituted an artistic unitary group. The present work seeks to analyze the social and artistic processes that allowed the diffusion of this Hispanic typology, and to explain the chronology, arrival and expansion of the of the romanesque porchs in this rural region.Este trabajo se realiza en el marco del proyecto: “Transferencias artís-ticas en la península ibérica (siglos IX a XII): recepción de la cultura visual islámica en los reinos cristianos” (I+D PID2020-118603RA-I00, del Ministerio de Ciencia e Innovación
The Passionary from Monastery of San Pedro de Cardeña (British Library, Add. Ms. 25600): New Contributions on its Dating and Authorship
No full textEl Pasionario de Cardeña, manuscrito actualmente conservado en la British Library de Londres (Add. Ms. 25600), ha acaparado la atención de numerosos especialistas, especialmente desde comienzos del siglo pasado. A partir de esos primeros trabajos, la autoría y la datación del Pasionario ha venido suscitando ciertas controversias. De una primera adscripción al copista Gómez, en el año 919, se propuso después otro scriptor, Endura, y una cronología algo posterior, mitad del siglo x. Los análisis llevados a cabo para el presente trabajo nos llevan a plantear otras hipótesis que se alejan de ambos escribas y a descartar, definitivamente, el año 919 para este manuscrito.The Passionary of Cardeña, a manuscript currently preserved in the British Library in London (Add. Ms. 25600), has been the subject of numerous studies, especially since the beginning of the last century. Since those early works, the authorship and dating of the Passionary has been the subject of some controversy. Starting from a first attribution to the copyist Gómez, in the year 919, another scriptor, Endura, was later proposed, dating the manuscript to a later chronology, the middle of the 10th century. The analyses carried out by the present study lead us to propose other hypotheses that move away from both copyist and to definitively rule out the year 919 for this manuscriptEste trabajo se enmarca dentro del proyecto financiado por el Ministerio de Ciencia e Innovación (PDI2019-108273GB-I00) «Élites clericales y afianzamiento territorial e institucional de la diócesis de Burgos (siglos XI al XV)», dirigido por la Dra. Guijarro González, de la Universidad de Cantabria, y ha sido realizado en el marco del Grupo de Investigación BULEVAFUENTES: Fuentes escritas de Castilla y León (ss. XV-XVI) de la Universidad de Burgos
Usage of ICT among Social Educators—An Analysis of Current Practice in Spain
No full textThe objective of this study is to identify the usage of ICT tools among social educators within their professional activity. Technology among social educators is currently a very up-to-date topic. This is a professional group with its own characteristics that are different from those of teachers or other professionals in formal education. A mixed sequential two-phase method was proposed for the study: both quantitative and qualitative. In the first phase, the EdSocEval_V2 questionnaire was applied to a sample of 504 social educators from 17 autonomous communities. In the second phase, four focus groups were formed. The results presented reduced and basic usage of ICT: in management and administrative tasks and for communication with conventional tools. The COVID-19 pandemic has likewise increased the need for the use of ICT in socio-educational interventions, although their use for intervention among these groups is still very scarce. Training in and raising awareness of ICT among professionals for social interventions are priorities, as is the construction of a referential framework for professional training