1,023 research outputs found

    Concepciones de algunos profesores de matem√°ticas de b√°sica secundaria sobre los decimales y su relaci√≥n, como representaci√≥n, con los n√ļmeros racionales

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    Esta investigaci√≥n enmarcada en el paradigma interpretativo y con una metodolog√≠a interpretativa, tiene como prop√≥sito identificar y caracterizar las concepciones de algunos profesores de matem√°ticas de b√°sica secundaria, sobre los decimales como representaci√≥n de los n√ļmeros racionales

    Dynamic pipelining of multidimensional range queries

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    The problem of evaluating orthogonal range queries efficiently has been studied widely in the data structures community. It has been common wisdom for several years that for queries containing more than 20% of the elements of the dataset a linear scanning of the data was the most efficient solution. In recent experimental works using modern hardware ‚Äďwith main memory and parallelism‚Äď the conclusion is that linear scan is preferable for almost every query configuration (even containing a 1% of the data). In this work we propose an alternative approach to evaluate multidimensional range queries based on the dynamic pipeline paradigm ‚Äďusing main memory and concurrency. Our aim is to prove that under this framework, it is possible to beat the performance of linear scanning by the one of hierarchical multidimensional data structures ‚Äďsuch as kd trees, quad trees, Rtrees or similar.Peer ReviewedPostprint (published version

    Assessing social performance of construction companies in public-works procurement: Data envelopment analysis based on the benefit of the doubt approach

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    [EN] There is an urgent need to improve the assessment of construction companies' Corporate Social Responsibility (CSR) in public-works procurement. Current procurement procedures assign a high level of subjectivity to CSR assessment and lack transparency. Existing research basically highlights the need to define weighting systems in which the importance of each social criterion is objective and based on the social weaknesses in the context of a project. In order to fulfill this gap, this research proposes a composite indicator for assessing CSR in public construction procurement. A Data Envelopment Analysis based on the Benefit of Doubt Approach (DEA-BOD) was chosen to define the weighting system based on the main social weaknesses that exist in the country where the contract is procured. The research employs simulation to assess the validity of this indicator. The results highlight that the use of national indices as a proxy for CSR indicators can be helpful in determining the level of importance of CSR in public procurement. The simulation showed that the proposed approach allows the objective comparison of CSR performance of construction companies, regardless of their size. This research assists decision-makers in properly integrating social sustainability in procurement procedures.The authors acknowledge the financial support of the Universitat Politecnica de Valencia (PAID -00-17) . The authors are grateful to the expert panel for their participation in this research.Montalbán-Domingo, L.; García-Segura, T.; Sanz-Benlloch, A.; Pellicer, E.; Torres-Machí, C.; Molenaar, K. (2022). Assessing social performance of construction companies in public-works procurement: Data envelopment analysis based on the benefit of the doubt approach. Environmental Impact Assessment Review. 96:1-15. https://doi.org/10.1016/j.eiar.2022.1068441159

    Soil Arthropods in the Douro Demarcated Region Vineyards : General Characteristics and Ecosystem Services Provided

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    Viticulture is one of the oldest and most profitable forms of agriculture; it is also one of the most intensive farming systems. As intensive cultivation threatens the environment, there is increasing interest in the concept of sustainability within the wine industry, as well as new business opportunities, as customers begin to pay more attention to environmental and sustainability issues. Recognizing the key role of soil quality in environmentally and economically sustainable viticulture makes it essential to understand better soil arthropod communities, given their crucial functions in maintaining soil quality and health. The 'Douro Demarcated Region' (DDR) in northern Portugal offers good potential, in regards to biodiversity, due to its significant areas of non-crop habitats. This work aims to compile information on soil arthropod communities (both soil surface and soil-living) collected in the DDR vineyard agroecosystems. A description of the ecosystem services provided by them, as a basis for the development and implementation of sustainable viticulture systems, is also an objective of this work. An important set of soil arthropods necessary for the delivery of vital ecosystem services for viticulture, with particular reference to supporting and regulating services, occurred in this ecosystem. Eight classes were chiefly represented in a sample of about 167,000 arthropod specimens: Arachnida, Chilopoda, Diplopoda, Entognatha, Insecta, Malacostraca, Pauropoda, and Symphyla. The most representative were Entognatha and Insecta in soil-surface arthropods, and Arachnida and Entognatha in soil-living arthropods. The presence of recognized groups as bioindicators in agroecosystems, such as soil quality indicators, is also revealed. This knowledge is expected to contribute to a more efficient and sustainable management of the viticultural ecosystem.Peer reviewe

    Implementing static synchronous sensor fields using NiMo

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    In this work we present some implementations of a Static Synchronous Sensor Field (SSSF), a static and synchronous model for sensor networks in which a finite set of sensing devices are geographically distributed and can communicate among them. We used for implementations the NiMo (Nets in Motion) programming language, a graphic-functional-data flow language that allows a step by step visualization of the executions of an algorithm, making visible all the involved elements. Experimenting with sensor networks gives an insight of their behavior and aids to see their properties.Postprint (published version

    Children's Health Habits and COVID-19 Lockdown in Catalonia : Implications for Obesity and Non-Communicable Diseases

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    Lockdown during the COVID-19 pandemic imposed changes in children's daily routine that could lead to changes in behavior patterns. Using a survey targeted at children under 17 years of age, we described dietary (adherence to Mediterranean diet, AMD) and sleeping habits (disorders of initiating and maintaining sleep) after the implementation of lockdown, and examined the probability of the inadequate frequency of physical activity (PA) and use of TV and electronic devices (TV-ED) before and after lockdown through generalized estimating equation models, accounting for age and gender differences. From 3464 children included, 53.2% showed optimal AMD; 79.2% referred to delayed bedtime; and 16.3% were suspected of sleeping disorders after the implementation of lockdown. Delay in bedtime was more frequent among children older than 6 years, and inadequate sleeping hours among those younger than 11 years. There were no gender differences in AMD or sleeping habits. The odds of inadequate frequency of PA and TV-ED use were greater after lockdown, with a greater risk for TV-ED use. Boys were at greater risk of inadequate PA frequency and TV-ED use. Odds ratio of inadequate PA was greater at older ages. Lockdown could influence changes in children's habits that could lead to risk factors for non-communicable diseases during adulthood if such behaviors are sustained over time

    Análisis exploratorio de los datos de determinación de edad de Mullus barbatus en el Mediterráneo

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    The uncertainty in age estimation by otolith reading may be at the root of the large variability in red mullet (Mullus barbatus) growth models in the Mediterranean. In the MEDITS survey, red mullet age data are produced following the same sampling protocol and otolith reading methodology. However, ageing is assigned using different interpretation schemes, including variations in theoretical birthdate and number of false rings considered, in addition to differences in the experience level of readers. The present work analysed the influence of these variations and the geographical location of sampling on red mullet ageing using a multivariate approach (principal component analysis). Reader experience was the most important parameter correlated with the variability. The number of rings considered false showed a significant effect on the variability in the first age groups but had less influence on the older ones. The effect of the theoretical birthdate was low in all age groups. Geographical location had a significant influence, with longitude showing greater effects than latitude. In light of these results, workshops, exchanges and the adoption of a common ageing protocol based on age validation studies are considered fundamental tools for improving precision in red mullet ageing.La incertidumbre en la estimaci√≥n de la edad mediante la lectura de otolitos puede ser la principal causa detr√°s de la gran variabilidad existente en los modelos de crecimiento del salmonete (Mullus barbatus) en el Mediterr√°neo. En la campa√Īa MEDITS, los datos de edad del salmonete se generan siguiendo el mismo protocolo de muestreo y metodolog√≠a de lectura de otolitos, aunque la asignaci√≥n de la edad se lleva a cabo usando distintos esquemas para la interpretaci√≥n de las lecturas, incluyendo variaciones en la fecha te√≥rica de nacimiento y en el n√ļmero de anillos considerados falsos, adem√°s de las diferencias existentes en cuanto al nivel de experiencia de los lectores. En este trabajo, la influencia de las variaciones en los esquemas de interpretaci√≥n, el nivel de experiencia de los lectores, y la localizaci√≥n geogr√°fica de las muestras, sobre la determinaci√≥n de la edad en el salmonete se analiza mediante una aproximaci√≥n multivariante (An√°lisis de Componentes Principales). La experiencia de los lectores fue el par√°metro m√°s correlacionado con la variabilidad. El n√ļmero de anillos considerados falsos mostr√≥ un efecto significativo sobre la variabilidad de los primeros grupos de edad, mientras que su influencia sobre los m√°s viejos fue menor. El efecto de la fecha te√≥rica de nacimiento tuvo poca importancia en todos los grupos de edad. La localizaci√≥n geogr√°fica tuvo una influencia significativa, con la longitud mostrando mayores efectos que la latitud. Teniendo en cuenta estos resultados, los grupos de trabajo e intercambios de otolitos as√≠ como la adopci√≥n de un protocolo de asignaci√≥n de edad com√ļn basado en estudios de validaci√≥n de edad, se consideran herramientas fundamentales para mejorar la precisi√≥n en la determinaci√≥n de la edad del salmonete

    Brentuximab vedotin in the treatment of cutaneous T-cell lymphomas: Data from the Spanish Primary Cutaneous Lymphoma Registry

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    [Background] Brentuximab vedotin (BV) has been approved for CD30-expressing cutaneous T-cell lymphoma (CTCL) after at least one previous systemic treatment. However, real clinical practice is still limited.[Objectives] To evaluate the response and tolerance of BV in a cohort of patients with CTCL.[Methods] We analysed CTCL patients treated with BV from the Spanish Primary Cutaneous Lymphoma Registry (RELCP).[Results] Sixty-seven patients were included. There were 26 females and the mean age at diagnosis was 59‚ÄČyears. Forty-eight were mycosis fungoides (MF), 7 S√©zary syndrome (SS) and 12 CD30+ lymphoproliferative disorders (CD30 LPD). Mean follow-up was 18‚ÄČmonths. Thirty patients (45%) showed at least 10% of CD30+ cells among the total lymphocytic infiltrate. The median number of BV infusions received was 7. The overall response rate (ORR) was 67% (63% in MF, 71% in SS and 84% in CD30 LPD). Ten of 14 patients with folliculotropic MF (FMF) achieved complete or partial response (ORR 71%). The median time to response was 2.8 months. During follow-up, 36 cases (54%) experienced cutaneous relapse or progression. The median progression free survival (PFS) was 10.3 months. The most frequent adverse event was peripheral neuropathy (PN) (57%), in most patients (85%), grades 1 or 2.[Conclusions] These results confirm the efficacy and safety of BV in patients with advanced-stage MF, and CD30 LPD. In addition, patients with FMF and SS also showed a favourable response. Our data suggest that BV retreatment is effective in a proportion of cases.The Spanish Primary Cutaneous Lymphoma Registry (RELCP) is promoted by the Fundaci√≥n Piel Sana Academia Espa√Īola de Dermatolog√≠a y Venereolog√≠a, which received an unrestricted grant support from Kyowa Kirin.Peer reviewe

    Prognostic implications of comorbidity patterns in critically ill COVID-19 patients: A multicenter, observational study

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    Background The clinical heterogeneity of COVID-19 suggests the existence of different phenotypes with prognostic implications. We aimed to analyze comorbidity patterns in critically ill COVID-19 patients and assess their impact on in-hospital outcomes, response to treatment and sequelae. Methods Multicenter prospective/retrospective observational study in intensive care units of 55 Spanish hospitals. 5866 PCR-confirmed COVID-19 patients had comorbidities recorded at hospital admission; clinical and biological parameters, in-hospital procedures and complications throughout the stay; and, clinical complications, persistent symptoms and sequelae at 3 and 6 months. Findings Latent class analysis identified 3 phenotypes using training and test subcohorts: low-morbidity (n=3385; 58%), younger and with few comorbidities; high-morbidity (n=2074; 35%), with high comorbid burden; and renal-morbidity (n=407; 7%), with chronic kidney disease (CKD), high comorbidity burden and the worst oxygenation profile. Renal-morbidity and high-morbidity had more in-hospital complications and higher mortality risk than low-morbidity (adjusted HR (95% CI): 1.57 (1.34-1.84) and 1.16 (1.05-1.28), respectively). Corticosteroids, but not tocilizumab, were associated with lower mortality risk (HR (95% CI) 0.76 (0.63-0.93)), especially in renal-morbidity and high-morbidity. Renal-morbidity and high-morbidity showed the worst lung function throughout the follow-up, with renal-morbidity having the highest risk of infectious complications (6%), emergency visits (29%) or hospital readmissions (14%) at 6 months (p<0.01). Interpretation Comorbidity-based phenotypes were identified and associated with different expression of in-hospital complications, mortality, treatment response, and sequelae, with CKD playing a major role. This could help clinicians in day-to-day decision making including the management of post-discharge COVID-19 sequelae. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd
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