Numerical modeling of solar ponds

A SGSP is a basin of water where solar energy is trapped due to an artificially imposed salinity gradient. In a SGSP three zones can be identified: the surface and bottom zones that are both convective and an intermediate zone in between which is intended to be non-convective. This zone acts as a transparent insulation and allows the storage of solar energy at the bottom where it is available for use. A numerical model where the SGSP dynamics is described in terms of velocity, pressure, temperature and salt concentration is presented. It is based on the Navier-Stokes equations for an incompressible fluid coupled to one advection-diffusion equation for and one advection-diffusion equation for . The fluid density is taken to depend on and and the Boussinesq hypothesis is adopted: the fluid density appearing in the LHS of the Navier-Stokes equation is supposed constant and equal to some reference value whereas it is assumed to be variable in the RHS. The space discretization of the governing equations is based on the respective weak formulations and the discretization employs finite elements with a pressure correction method used to decouple velocity and pressure. Integration in time is accomplished by a BDF (Backward Differentiation Formula) method with the above PDEs treated sequentially within each time step. A computer code was developed employing the finite element class library deal.II. Comparisons with available experimental results are made to validate this numerical model

Thermal energy production by a dual solar pound

A Salt Gradient Solar Pond (SGSP) is a salt water basin that collects and stores solar energy. These devices rely on the existence of a non-convective zone (NCZ) that functions as a transparent thermal insulation zone, created by a salt gradient. Salinity and temperature gradients in this zone can give rise to double diffusive problems that can decrease the insulation properties of this zone. The stability of this zone is thus crucial in a SGSP. Stability control, analysis of energy extraction, device efficiency and maintenance strategies are determinant for the correct performance of the SGSP. The implementation of these strategies can be expensive and not sufficient to prevent instability problems. This paper intends to give a contribution to the maintenance problem presenting a new concept of a SGSP utilisation: The Dual Solar Pond (DSP

Large-scale Nonlinear Variable Selection via Kernel Random Features

We propose a new method for input variable selection in nonlinear regression. The method is embedded into a kernel regression machine that can model general nonlinear functions, not being a priori limited to additive models. This is the first kernel-based variable selection method applicable to large datasets. It sidesteps the typical poor scaling properties of kernel methods by mapping the inputs into a relatively low-dimensional space of random features. The algorithm discovers the variables relevant for the regression task together with learning the prediction model through learning the appropriate nonlinear random feature maps. We demonstrate the outstanding performance of our method on a set of large-scale synthetic and real datasets.Comment: Final version for proceedings of ECML/PKDD 201

Estudio del proceso de cambio conceptual y la construcción del modelo científico precursor de ser vivo en niños de pre-escolar

La presente investigación estudia el cambio conceptual y la construcción de modelos científicos precursores en un contexto socioconstructivista con niños pequeños, utilizando una metodología cualitativa. Se analizan los cambios epistemológicos y ontológicos en las concepciones de los niños acerca de los seres vivos y cómo una estrategia didáctica basada en la construcción de un modelo científico precursor basado en propiedades biológicas los promueven. Los cambios en la comprensión de los niños fueron significativos en las dimensiones ontológicas y epistemológicas, presentando diferentes patones. Los segundos proporcionaron una mejor coherencia explicativa en su sistema conceptual contribuyendo, de esta forma, a los cambios ontológicos y promoviendo, a su vez, la construcción del modelo científico precursor de ser vivo

Determining appropriate approaches for using data in feature selection

Feature selection is increasingly important in data analysis and machine learning in big data era. However, how to use the data in feature selection, i.e. using either ALL or PART of a dataset, has become a serious and tricky issue. Whilst the conventional practice of using all the data in feature selection may lead to selection bias, using part of the data may, on the other hand, lead to underestimating the relevant features under some conditions. This paper investigates these two strategies systematically in terms of reliability and effectiveness, and then determines their suitability for datasets with different characteristics. The reliability is measured by the Average Tanimoto Index and the Inter-method Average Tanimoto Index, and the effectiveness is measured by the mean generalisation accuracy of classification. The computational experiments are carried out on ten real-world benchmark datasets and fourteen synthetic datasets. The synthetic datasets are generated with a pre-set number of relevant features and varied numbers of irrelevant features and instances, and added with different levels of noise. The results indicate that the PART approach is more effective in reducing the bias when the size of a dataset is small but starts to lose its advantage as the dataset size increases

Proof of concept of a treatment for fibromyalgia based on physical activity, psychological support, and exposure to nature (NAT-FM)

Aim: To provide a preliminary assessment of the efficacy of the NAT-FM protocol as a complimentary treatment in patients with fibromyalgia (FM). Methods: A trial was conducted, with two arms: TAU (n = 6) and TAU+NAT-FM (n = 6). Results: There was a reduction in physical limitations and anxious/depressive symptoms and an improvement in positive affect in the intervention group. Also, this group showed a decrease in pain, catastrophizing, negative affect, and positively refocusing, and an increase in positive affect. Intrasession assessments showed an increase in positive affect, self-efficacy, and energy, along with a decrease in stress. Intersession assessments revealed an increase in pain, valence, and dominance. Conclusion: The results suggest the appropriateness of the NAT-FM protocol

Immunitat de grup : els adults joves, fora del ramat?

Un estudi troba que la confiança en actors clau en la gestió de crisis sanitàries, les actituds, la informació i les creences conspiratives eren claus per predir si els joves adults rebutjaven vacunar-se contra el virus SARS-CoV-2. Per tant, en cas d'una possible nova crisi sanitària, serà cabdal una adequada gestió de la comunicació per part dels actors implicats.Un estudio halla que la confianza en actores clave en la gestión de crisis sanitarias, las actitudes, la información y las creencias conspirativas eran claves para predecir si los jóvenes adultos rechazaban vacunarse contra el virus SARS-CoV-2. Por tanto, ante una posible nueva crisis sanitaria, será primordial una adecuada gestión de la comunicación por parte de los actores implicados.Study finds trust in key actors in health crisis management, attitudes, information, and conspiratorial beliefs were key to predicting whether young adults refused to be vaccinated against the SARS-CoV-2 virus. Therefore, in the face of a possible new health crisis, proper communication management by the actors involved will be absolutely essential

Design fundamentals of mentoring programs for pharmacy professionals (Part 1): Considerations for organizations

Mentoring programs have been offered by organizations within and outside of healthcare for years. This commentary examines the literature under the prism of design fundamentals for these programs, drawing particular considerations for schemes aimed at pharmacy professionals. The central argument presented is that mentoring can be used as a vehicle to support pharmacists to learn from others and each other, to reinforce and own their professional identity so that the uniqueness of the pharmacy profession is established within a global health landscape of constant change. In this Part 1 of a series of papers, a wealth of literature, theories, and evidence are presented aiming to inform the general structure and logistical considerations for both in-person and distance mentoring programs

Efficacy of a Multicomponent Intervention for Fibromyalgia Based on Pain Neuroscience Education, Exercise Therapy, Psychological Support, and Nature Exposure (NAT-FM) : Study Protocol of a Randomized Controlled Trial

The study protocol of a prospective and randomized controlled trial for the assessment of the efficacy of nature activity therapy for people with Fibromyalgia (NAT-FM) is described. The primary outcome is the mean change from baseline in the Revised Fibromyalgia Impact Questionnaire (FIQR) score at post-treatment (12 weeks) and at 9 months of follow-up, and secondary outcomes are changes in the positive affect, negative affect, pain, fatigue, self-efficacy, catastrophising, and emotional regulation. A total of 160 patients with fibromyalgia will be divided into two arms: treatment-as-usual (TAU) and NAT-FM+TAU. Pre, during, post, +6, and +9 months assessments will be carried out, as well as an ecological momentary assessment (EMA) of intrasession and intersessions. Results will be subjected to a mixed group (NAT-FM+TAU vs. TAU) × phase (pre, post, +6 months, +9 months) general linear model. EMA intrasession measurements will be subjected to a 2 (pre vs. post) × 5 (type of activity) mixed-effects ANOVA. EMA between-session measurements obtained from both arms of the study will be analysed on both a time-domain and frequency-domain basis. Effect sizes and number needed to treat (NNT) will be computed. A mediation/moderation analysis will be conducted