Geodetic works carried out in the Strait of Gibraltar

The proximity between Europe and Africa and the fact that the Strait of Gibraltar has historically acted as a link between races, cultures and religions have made absolutely necessary to establish a relationship between the Northern African coast and the Southern European equivalent. From the Nineteenth Century the possibility of building a permanent link between both continents through the Strait of Gibraltar has been taken into account. In order to establish that relationship it is necessary to have coastal zones completely geo-referenced, under the same geodetic system and with a unique projection system. The paper describes the work carried out in the Strait of Gibraltar for this purpose

RecruitNet: A global database of plant recruitment networks

Plant recruitment interactions (i.e., what recruits under what) shape the composition, diversity, and structure of plant communities. Despite the huge body of knowledge on the mechanisms underlying recruitment interactions among species, we still know little about the structure of the recruitment networks emerging in ecological communities. Modeling and analyzing the community-level structure of plant recruitment interactions as a complex network can provide relevant information on ecological and evolutionary processes acting both at the species and ecosystem levels. We report a data set containing 143 plant recruitment networks in 23 countries across five continents, including temperate and tropical ecosystems. Each network identifies the species under which another species recruits. All networks report the number of recruits (i.e., individuals) per species. The data set includes >850,000 recruiting individuals involved in 118,411 paired interactions among 3318 vascular plant species across the globe. The cover of canopy species and open ground is also provided. Three sampling protocols were used: (1) The Recruitment Network (RN) protocol (106 networks) focuses on interactions among established plants (“canopy species”) and plants in their early stages of recruitment (“recruit species”). A series of plots was delimited within a locality, and all the individuals recruiting and their canopy species were identified; (2) The paired Canopy-Open (pCO) protocol (26 networks) consists in locating a potential canopy plant and identifying recruiting individuals under the canopy and in a nearby open space of the same area; (3) The Georeferenced plot (GP) protocol (11 networks) consists in using information from georeferenced individual plants in large plots to infer canopy-recruit interactions. Some networks incorporate data for both herbs and woody species, whereas others focus exclusively on woody species. The location of each study site, geographical coordinates, country, locality, responsible author, sampling dates, sampling method, and life habits of both canopy and recruit species are provided. This database will allow researchers to test ecological, biogeographical, and evolutionary hypotheses related to plant recruitment interactions. There are no copyright restrictions on the data set; please cite this data paper when using these data in publications. © 2022 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America

Destrezas matemáticas previas de los estudiantes de grado en Ingenierías y Arquitectura

Muchos profesores de asignaturas de física y de matemáticas que imparten docencia en el primer curso de las titulaciones técnicas de Grado detectan un empeoramiento de las destrezas matemáticas básicas de los alumnos de nuevo ingreso. Esta situación dificulta el proceso de enseñanza-aprendizaje y lastra negativamente las posibilidades de éxito de muchos estudiantes de primer curso. Esta clara sensación, sin embargo necesita de una definición cuantitativa. En este proyecto, nos planteamos realizar un análisis cuantitativo de las destrezas en matemáticas básicas de los nuevos matriculados en las titulaciones de Grado de la Escuela Politécnica Superior (EPS), para impulsar un debate en la comunidad universitaria y pre-universitaria que lleve a proponer medidas concretas dirigidas a mejorar las habilidades en nuestros estudiantes

Population prevalence and control of cardiovascular risk factors : What electronic medical records tell us

To analyze the prevalence, control, and management of hypertension, hypercholesterolemia, and diabetes mellitus type 2 (DM2). Cross-sectional analysis of all individuals attended in the Catalan primary care centers between 2006 and 2009. History of cardiovascular diseases, diagnosis and treatment of hypertension, hypercholesterolemia, DM2, lipid profile, glycemia and blood pressure data were extracted from electronic medical records. Age-standardized prevalence and levels of management and control were estimated. Individuals aged 35-74 years using primary care databases. A total of 2,174,515 individuals were included (mean age 52 years [SD 11], 47% men). Hypertension was the most prevalent cardiovascular risk factor (39% in women, 41% in men) followed by hypercholesterolemia (38% and 40%) and DM2 (12% and 16%), respectively. Diuretics and angiotensin-converting enzyme inhibitors were most often prescribed for hypertension control (<140/90 mmHg, achieved in 68% of men and 60% of women treated). Hypercholesterolemia was controlled (low-density lipoprotein cholesterol <130 mg/dl) in just 31% of men and 26% of women with no history of cardiovascular disease, despite lipid-lowering treatment, primarily (90%) with statins. The percentage of women and men with DM2 and with glycated hemoglobin <7% was 64.7% and 59.2%, respectively; treatment was predominantly with oral hypoglycemic agents alone (70%), or combined with insulin (15%). Hypertension was the most prevalent cardiovascular risk factor in the Catalan population attended at primary care centers. About two thirds of individuals with hypertension or DM2 were adequately controlled; hypercholesterolemia control was particularly low

Channel estimation method with improved performance for the UMTS-TDD mode

Channel estimation is an essential building block for UTRA-TDD high performance receivers. Once the performance of the channel estimator algorithm proposed by 3GPP is highly dependent on the time spreading between consecutive multi-path components, a Successive Multi-path channel Estimation Technique (SMET) that improves the time resolution is proposed in this paper. A SMET based maximum likelihood approach for vectorial channel estimation, to include the estimation of the direction-of-arrival, is also proposed. This algorithm solves efficiently the complex problem of DOA estimation of multiple users in a multi path propagation environment even when the number of required DOA's exceeds the number of antenna array elements. Another property of the proposed algorithm is its ability to resolve signals from different users arriving from the same direction. This is due to processing in both time and space dimensions. The performance of these algorithms is assessed by resorting to simulations in multi-path environments using the UMTS-TDD specifications, and also by comparing the rms estimation errors against the Crámer-Rao Bound. The effect of imperfect channel estimation on the performance of RAKE and Hard-Decision Parallel Interference Canceller receivers is also analysed. The results show that a good performance can be achieved with SMET, from low to high values of Eb/n0

Coexistence of elastic modulations in the charge density wave state of 2H-NbSe₂

Bulk and single-layer 2H-NbSe₂ exhibit identical charge density wave order (CDW) with a quasi-commensurate 3 × 3 superlattice periodicity. Here we combine scanning tunnelling microscopy (STM) imaging at T = 1 K of 2H-NbSe₂ with first-principles density functional theory (DFT) calculations to investigate the structural atomic rearrangement of this CDW phase. Our calculations for single-layers reveal that six different atomic structures are compatible with the 3 × 3 CDW distortion, although all of them lie on a very narrow energy range of at most 3 meV per formula unit, suggesting the coexistence of such structures. Our atomically resolved STM images of bulk 2H-NbSe₂ unambiguously confirm this by identifying two of these structures. Remarkably, these structures differ from the X-ray crystal structure reported for the bulk 3 × 3 CDW which in fact is also one of the six DFT structures located for the single-layer. Our calculations also show that due to the minute energy difference between the different phases, the ground state of the 3 × 3 CDW could be extremely sensitive to doping, external strain or internal pressure within the crystal. The presence of multiphase CDW order in 2H-NbSe₂ may provide further understanding of its low temperature state and the competition between different instabilities

Valorization of wastewater from table olives: NMR identification of antioxidant phenolic fraction and microwave single-phase reaction of sugary fraction

The table olive industry is producing a huge amount of wastewater, which is a post-processing cost and an environmental concern. The present study aims to valorize this processing by-product to obtain a value-added product, thereby enhancing resource efficiency and contributing to achieving sustainable development goals (SDGs). In this sense, a chemical reaction-based platform was developed to obtain valuable components, such as levulinic acid (LA) and 5-hydromethylfurfural (HMF). The products were then analyzed using NMR identification of the antioxidant phenolic fraction and microwave single-phase reaction of the sugary fraction. According to the results, the highest concentration of phenolic compounds does not correspond to the sample directly obtained from NaOH treatment (S1), indicating that water washing steps (S2-S5) are fundamental to recover phenolic substances. Moreover, glucose was presented in the sugary fraction that can be transformed into levulinic acid by a single-phase reaction under microwave irradiation. The information provided in this manuscript suggests that the wastewater from the olive processing industry can be valorized to obtain valuable products

Table olive wastewater as a potential source of biophenols for valorization : a mini review

The table olive industry generates high amounts of wastewater annually during the alkaline treatment, fermentation, and washing steps of olives. High conductivity and salt content, as well as the high organic and biophenol contents of these waters, is a worldwide problem, especially in the Mediterranean region, which is the major table olive producing area. There is a wide variety of bioactives found in wastewater derived from table olive processing. The main compounds of table olive wastewater, such as those derived from phenolic, hydrocarbon, and sugar fractions, can be recovered and reused. In this review, the table olive manufacturing processes and the volumes and composition of wastewater generated from the different methods of table olive processing are discussed. In addition, biophenols of table olive water and their biological activities are also introduced. The high concentrations of valuable biophenols, such as tyrosol and hydroxytyrosol, show promising potential for valorizing table olive wastewater; however, more research is needed in this area

The role of a firm's absorptive capacity and the technology transfer process in clusters: How effective are technology centres in low-tech clusters?

This paper analyses how the internal resources of small- and medium-sized enterprises determine access (learning processes) to technology centres (TCs) or industrial research institutes (innovation infrastructure) in traditional low-tech clusters. These interactions basically represent traded (market-based) transactions, which constitute important sources of knowledge in clusters. The paper addresses the role of TCs in low-tech clusters, and uses semi-structured interviews with 80 firms in a manufacturing cluster. The results point out that producer–user interactions are the most frequent; thus, the higher the sector knowledge-intensive base, the more likely the utilization of the available research infrastructure becomes. Conversely, the sectors with less knowledge-intensive structures, i.e. less absorptive capacity (AC), present weak linkages to TCs, as they frequently prefer to interact with suppliers, who act as transceivers of knowledge. Therefore, not all the firms in a cluster can fully exploit the available research infrastructure, and their AC moderates this engagement. In addition, the existence of TCs is not sufficient since the active role of a firm's search strategies to undertake interactions and conduct openness to available sources of knowledge is also needed. The study has implications for policymakers and academia

Estudio de la inserción de reactividad introducida por la secuencia de movimientos de los bancos de barras de control. Aplicación a un transitorio de reducción de potencia

[ES] En el conjunto de estudios del estado del núcleo del reactor que deben realizarse para asegurar la seguridad e integridad del mismo a lo largo de un ciclo de operación, debe prestarse especial atención a los fenómenos producidos por la inserción de reactividades como, por ejemplo, los debidos a los movimientos de los grupos de barras de control, los cuales suelen estar predefinidos por el proveedor de la tecnología en las Especificaciones Técnicas de Funcionamiento. El presente trabajo realiza un estudio acerca de en qué medida la elección de un determinado criterio para el movimiento y selección de los grupos de barras de control puede provocar una determinada inserción de reactividad. De esta forma, se ha realizado un análisis sensibilidad de la reactividad provocada por la extracción o inserción de un determinado grupo de barras de control y su influencia en el estado del núcleo del reactor e incluso en su posible evolución en un transitorio. El estudio de los diferentes casos contemplados se ha realizado mediante el uso del código acoplado termohidráulico-neutrónico TRACE v5.0 patch 3/PARCS v3.0, siendo el modelo escogido representativo de los datos de planta que podríamos encontrar en un reactor comercial PWR.Martorell, JB.; Olmo-Juan, N.; Barrachina, TM.; Miró Herrero, R.; Verdú Martín, GJ.; Garcia-Fenoll, M.; Posada, JM. (2019). Estudio de la inserción de reactividad introducida por la secuencia de movimientos de los bancos de barras de control. Aplicación a un transitorio de reducción de potencia. Sociedad Nuclear Española. 1-8. http://hdl.handle.net/10251/1809611