468 research outputs found

    Learning Bayesian Networks for Student Modeling

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    In the last decade, there has been a growing interest in using Bayesian Networks (BN) in the student modelling problem. This increased interest is probably due to the fact that BNs provide a sound methodology for this difficult task. In order to develop a Bayesian student model, it is necessary to define the structure (nodes and links) and the parameters. Usually the structure can be elicited with the help of human experts (teachers), but the difficulty of the problem of parameter specification is widely recognized in this and other domains. In the work presented here we have performed a set of experiments to compare the performance of two Bayesian Student Models, whose parameters have been specified by experts and learnt from data respectively. Results show that both models are able to provide reasonable estimations for knowledge variables in the student model, in spite of the small size of the dataset available for learning the parametersUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    The Campo de Calatrava volcanic field: geology and resources.

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    The volcanic region of Campo de Calatrava, located in South-Central Spain, and in particular in the Ciudad Real Province (Castilla-La Mancha region) is one of the three most important areas with recent volcanic activity in the Iberian Peninsula, together with those of Olot (Gerona, in Catalonia) and Cabo de Gata (Almeria, in Andalucía). In this work we describe succinctly the characteristics of this volcanism, as well as the related iron and manganese (plus minor cobalt) oxides mineralizations. Finally, an also brief description of the legal measures implemented to protect the local volcanic buildings is included

    Survival analysis of author keywords: An application to the library and information sciences area

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    "This is the peer reviewed version of the following article: Peset, F, F Garzón-Farinós, LM González, X García-Massó, A Ferrer-Sapena, JL Toca-Herrera, and EA Sánchez-Pérez. 2019. "Survival Analysis of Author Keywords: An Application to the Library and Information Sciences Area." Journal of the Association for Information Science and Technology 71 (4). Wiley: 462-73. doi:10.1002/asi.24248, which has been published in final form at https://doi.org/10.1002/asi.24248. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[EN] Our purpose is to adapt a statistical method for the analysis of discrete numerical series to the keywords appearing in scientific articles of a given area. As an example, we apply our methodological approach to the study of the keywords in the Library and Information Sciences (LIS) area. Our objective is to detect the new author keywords that appear in a fixed knowledge area in the period of 1 year in order to quantify the probabilities of survival for 10 years as a function of the impact of the journals where they appeared. Many of the new keywords appearing in the LIS field are ephemeral. Actually, more than half are never used again. In general, the terms most commonly used in the LIS area come from other areas. The average survival time of these keywords is approximately 3 years, being slightly higher in the case of words that were published in journals classified in the second quartile of the area. We believe that measuring the appearance and disappearance of terms will allow understanding some relevant aspects of the evolution of a discipline, providing in this way a new bibliometric approach.Peset Mancebo, MF.; Garzón Farinós, MF.; Gonzalez, L.; García-Massó, X.; Ferrer Sapena, A.; Toca-Herrera, JL.; Sánchez Pérez, EA. (2020). 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    Perspective on Dentoalveolar Manifestations Resulting from PHOSPHO1 Loss-of-Function: A Form of Pseudohypophosphatasia?

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    Mineralization of the skeleton occurs by several physicochemical and biochemical processes and mechanisms that facilitate the deposition of hydroxyapatite (HA) in specific areas of the extracellular matrix (ECM). Two key phosphatases, phosphatase, orphan 1 (PHOSPHO1) and tissue-non-specific alkaline phosphatase (TNAP), play complementary roles in the mineralization process. The actions of PHOSPHO1 on phosphocholine and phosphoethanolamine in matrix vesicles (MVs) produce inorganic phosphate (P(i)) for the initiation of HA mineral formation within MVs. TNAP hydrolyzes adenosine triphosphate (ATP) and the mineralization inhibitor, inorganic pyrophosphate (PP(i)), to generate P(i) that is incorporated into MVs. Genetic mutations in the ALPL gene-encoding TNAP lead to hypophosphatasia (HPP), characterized by low circulating TNAP levels (ALP), rickets in children and/or osteomalacia in adults, and a spectrum of dentoalveolar defects, the most prevalent being lack of acellular cementum leading to premature tooth loss. Given that the skeletal manifestations of genetic ablation of the Phospho1 gene in mice resemble many of the manifestations of HPP, we propose that Phospho1 gene mutations may underlie some cases of “pseudo-HPP” where ALP may be normal to subnormal, but ALPL mutation(s) have not been identified. The goal of this perspective article is to compare and contrast the loss-of-function effects of TNAP and PHOSPHO1 on the dentoalveolar complex to predict the likely dental phenotype in humans that may result from PHOSPHO1 mutations. Potential cases of pseudo-HPP associated with PHOSPHO1 mutations may resist diagnosis, and the dental manifestations could be a key criterion for consideration

    Semaglutide in type 2 diabetes with chronic kidney disease at high risk progression—real-world clinical practice

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    Albuminuria; Obesity; SemaglutideAlbuminúria; Obesitat; SemaglutidaAlbuminuria; Obesidad; SemaglutidaBackground Semaglutide [glucagon-like peptide-1 receptor-agonist (GLP-1RA)] has shown nephroprotective effects in previous cardiovascular studies. However, its efficacy and safety in patients with chronic kidney disease (CKD) and type 2 diabetes (T2D) have been rarely studied. Methods This is a multicenter, retrospective, observational study in patients with T2D and CKD with glycosylated hemoglobin A1c (HbA1c) of 7.5–9.5% treated with subcutaneous semaglutide for 12 months in real-world clinical practice. The main objectives were glycemic control as HbA1c 5%. Results We studied a total of 122 patients, ages 65.50 ± 11 years, 62% men, duration of T2D 12 years, baseline HbA1c 7.57% ± 1.36% and an estimated glomerular filtration rate (eGFR) 50.32 ± 19.21 mL/min/1.73 m2; 54% had a urinary albumin:creatinine ratio (UACR) of 30–300 mg/g and 20% had a UACR >300 mg/g. After 12 months of follow-up, HbA1c declined −0.73% ± 1.09% (P 5% of their body weight. Systolic and diastolic blood pressure decreased −9.85 mmHg and −5.92 mmHg, respectively (P 300 mg/g). The mean eGFR (by the Chronic Kidney Disease Epidemiology Collaboration) remained stable. The need for basal insulin decreased 20% (P < .005). Only 7% of patients on insulin had mild hypoglycemic episodes. Semaglutide was stopped in 5.7% of patients for digestive intolerance. Conclusions In this real-world study, patients with T2D and CKD treated with subcutaneous semaglutide for 12 months significantly improved glycemic control and decreased weight. Albuminuria decreased by >50% in patients with macroalbuminuria. The administration of GLP-1RA in patients with T2D and CKD was safe and well tolerated

    Using machine learning techniques for architectural design tracking: An experimental study of the design of a shelter

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    In this paper, we present a study aimed at tracking and analysing the design process. More concretely, we intend to explore whether some elements of the conceptual design stage in architecture might have an influence on the quality of the final project and to find and assess common solution pathways in problem-solving behaviour. In this sense, we propose a new methodology for design tracking, based on the application of data analysis and machine learning techniques to data obtained in snapshots of selected design instants. This methodology has been applied in an experimental study, in which fifty-two novice designers were required to design a shelter with the help of a specifically developed computer tool that allowed collecting snapshots of the project at six selected design instants. The snapshots were described according to nine variables. Data analysis and machine learning techniques were then used to extract the knowledge contained in the data. More concretely, supervised learning techniques (decision trees) were used to find strategies employed in higher-quality designs, while unsupervised learning techniques (clustering) were used to find common solution pathways. Results provide evidence that supervised learning techniques allow elucidating the class of the best projects by considering the order of some of the decisions taken. Also, unsupervised learning techniques can find several common problem-solving pathways by grouping projects into clusters that use similar strategies. In this way, our work suggests a novel approach to design tracking, using quantitative analysis methods that can complement and enrich the traditional qualitative approachThis work has been partially funded by the Spanish Government, Agencia Estatal de Investigación (AEI), and the European Union, Fondo Europeo de Desarrollo Regional (FEDER), grant TIN2016-80774-R (AEI/FEDER, UE). Funding for open access charge: Universidad de Málaga/CBUA

    A distinctive patchy osteomalacia characterises Phospho1-deficient mice

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    The phosphatase PHOSPHO1 is involved in the initiation of biomineralisation. Bones in Phospho1 KO mice show histological osteomalacia with frequent bowing of long bones and spontaneous fractures: they contain less mineral, with smaller mineral crystals. However, the consequences of Phospho1 ablation on the microscale structure of bone are not yet fully elucidated. Tibias and femurs obtained from wild-type and Phospho1 null (KO) mice (25-32 week-old) were embedded in PMMA, cut and polished to produce near longitudinal sections. Block surfaces were studied using 20kV backscattered-electron (BSE) imaging, and again after iodine staining to reveal non-mineralised matrix and cellular components. For 3D characterisation, we used x-ray microtomography. Bones opened with carbide milling tools to expose endosteal surfaces were macerated using an alkaline bacterial pronase enzyme detergent, 5% hydrogen peroxide and 7% sodium hypochlorite solutions to produce 3D surfaces for study with 3D BSE scanning electron microscopy. Extensive regions of both compact cortical and trabecular bone matrix in Phospho1 KO mice contained no significant mineral and/or showed arrested mineralisation fronts, characterised by a failure in the fusion of the calcospherite-like, separately mineralising, individual micro-volumes within bone. Osteoclastic resorption of the uncalcified matrix in Phospho1 KO mice was attenuated compared with surrounding normally-mineralised bone. The extent and position of this aberrant biomineralisation varied considerably between animals, contralateral limbs and anatomical sites. The most frequent manifestation lay, however, in the nearly complete failure of mineralisation in the bone surrounding the numerous transverse blood vessel canals in the cortices

    Two alkaline phosphatase genes are expressed during early development in the mouse embryo

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    Alkaline phosphatase (AP) activity is stage specific in mouse embryos and may be associated with compaction and separation of trophectoderm from inner cell mass in preimplantation development. We previously sequenced a cDNA and two mouse AP genes that could contribute to the AP activity in embryos. Oligonucleotide primers were constructed from the three sequences and used in the reverse transcription-polymerase chain reaction technique to establish that two of the three AP isozymes are transcribed during preimplantation development. The predominant transcript (E-AP) is from a gene highly homologous to the human tissue-specific APs, but different from the mouse intestinal AP. Tissue non- specific (TN) AP also is transcribed, but there is approximately 10 times less TN-AP than E-AP tran- script. The TN-AP isozyme is the predominant tran- script of 7 to 14 day embryos and primordial germ cells. A switch in predominance from E-AP to TN-AP must occur during early postimplantation development. This study establishes a framework for experiments to determine the functions of the two isozymes during preimplantation development
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