O Xardín Botánico de Caracas

[Resumo] Os xardíns botánicos non poden entenderse só como coleccións de magníficos exemplares; teñen un importante papel social (educativo, de ocio e tamén estético), ambiental (pulmón verde) e científico (investigación, preservación da biodiversidade e conservación fitoxenética). O Xardín Botánico de Caracas ten unha interesante colección de plantas vivas (200 000 plantas sementadas de 2000 especies diferentes) expostas de forma temática. Inicialmente eran plantas da xeografía venezolana máis foi ampliándose a colección a través de expedicións científicas, intercambios e donacións de coleccionistas. O xardín conta ademáis cun Herbario e unha Biblioteca, ademáis das instalacións do Instituto Botánico.[Abstract] Botanic gardens are more than just a collection of plant specimens; they also provide important roles within leisure, conservation, environmental education and scientific research. The botanic garden of Caracas contains a living collection of over 200,000 plants, which represents 2000 different species. Originally, the collection comprised of native Venezuela plants and then expanded through scientific expeditions, exchanges and donations from collectors. Caracas botanic garden facilities include a library and herbarium

Development of an Ultra-High Performance Concrete Joint Detail for Short-Span Bridges

Slab beam superstructures have been used for short-span bridges since prestressed concrete began to be used in the US. Poor joint performance of these superstructures led to recent revisions to design standards; one example being the Florida Slab Beam (FSB). The FSB and other similar slab beam systems include a composite cast-in-place (CIP) reinforced concrete deck and joint between adjacent beams. An optimized joint design has been developed to accelerate the construction times and eliminate the need for a CIP deck by using ultra-high performance concrete (UHPC) in the longitudinal closure pour to connect the precast members. The optimized joint design was first developed from eight different cross-section and joint reinforcement details (four 18-inch deep specimens including the control, and four 12-inch deep specimens), investigating the joint transverse service and strength behavior in a small-scale experimental testing protocol. All the specimens were transversely supported and tested under a three-point load setup, applying the load adjacently to the joint region. All 18-inch deep joints performed similar to the current FSB design, while the 12-inch deep specimen with the lowest joint reinforcement placement had the largest transverse strength capacity among those of the same thickness. The best joint geometry performer from the 12-inch deep specimens in the small-scale protocol was selected to investigate further the overall joint behavior with 30-foot length specimens. Two two-beam test configurations with UHPC joints were developed and experimentally tested under strength and cyclic performance with different loading schemes and support conditions, investigating the load transfer mechanisms, and the demand on the precast concrete, joint reinforcement, and joint interface. The joint performed well with no observed joint distress or deterioration in performance through the permit service load testing, more than four million cycles of load, and ultimate strength testing of the two-beam systems. Results from these tests and numerical models were used to guide in the subsequent design and construction aids of the new FSB system for accelerated construction to replace aging short-span bridges

O Xardín Botánico de Caracas

Botanic gardens are more than just a collection of plant specimens; they also provide important roles within leisure, conservation, environmental education and scientific research. The botanic garden of Caracas contains a living collection of over 200,000 plants, which represents 2000 different species. Originally, the collection comprised of native Venezuela plants and then expanded through scientific expeditions, exchanges and donations from collectors. Caracas botanic garden facilities include a library and herbarium.Os xardíns botánicos non poden entenderse só como coleccións de magníficos exemplares; teñen un importante papel social (educativo, de ocio e tamén estético), ambiental (pulmón verde) e científico (investigación, preservación da biodiversidade e conservación fitoxenética). O Xardín Botánico de Caracas ten unha interesante colección de plantas vivas (200 000 plantas sementadas de 2000 especies diferentes) expostas de forma temática. Inicialmente eran plantas da xeografía venezolana máis foi ampliándose a colección a través de expedicións científicas, intercambios e donacións de coleccionistas. O xardín conta ademáis cun Herbario e unha Biblioteca, ademáis das instalacións do Instituto Botánico

Improvement of Concrete Characterization Using Nanosilica

In recent years, different research works have been conducted to evaluate the addition of nanometer materials to concrete materials. In this paper, the influence of Nanosilica on compressive strength, abrasive strength, durability, and improvements in the micro-structure of concrete are discussed. The results showed that the compressive strength of concrete samples with Nanosilica and silica fume were higher than the compressive strength of other samples without nanometer materials in all ages, as well as increasing the dosage percentage of Nanosilica led to higher levels of compressive strength. In the mix designs with an equal dosage percentage, samples containing Nanosilica have shown a higher level of strength in comparison to samples containing silica fume. The application of Nanosilica in self-compacting concrete resulted in higher level of compressive strength, flexural strength, abrasive strength, elasticity module, ultrasonic waves permeability velocity (UPV), and lower water absorption compared to samples without Nanoparticles. Despite the evidences which show the improvement in mechanical characteristics of concretes with Nanosilica-particles, further developments for the applicability of Nanoparticles for improving the characteristics of concrete require the right knowledge and higher control over the effective mechanisms of Nanoparticles on concrete’s structure

Target-independent high-throughput sequencing methods provide evidence that already known human viral pathogens play a main role in respiratory infections with unexplained etiology

Despite the advanced PCR-based assays available, a fraction of the pediatric respiratory infections remain unexplained every epidemic season, and there is a perception that novel viruses might be present in these specimens. We systematically collected samples from a prospective cohort of pediatric patients with respiratory infections, that returned negative results by validated molecular RT-PCR assays, and studied them with a target-independent, high-throughput sequencing-based approach. We also included a matched cohort of children with no symptoms of respiratory infection, as a contrast study population. More than fifty percent of the specimens from the group of patients with unexplained respiratory infections were resolved. However, the higher rate of detection was not due to the presence of novel viruses, but to the identification of well-known viral respiratory pathogens. Our results show that already known viral pathogens are responsible for the majority of cases that remain unexplained after the epidemic season. High-throughput sequencing approaches that use pathogen-specific probes are easier to standardize because they ensure reproducible library enrichment and sequencing. In consequence, these techniques might be desirable from a regulatory standpoint for diagnostic laboratories seeking to benefit from the many advantages of these sequencing technologies.This work was supported by The Joint Science and Technology Office for Chemical and Biological Defense (JSTO-CBD) of the Defense Threat Reduction Agency (DTRA) under plan #CB10246. This study has been partially supported by Fondo de Investigaciones Sanitarias (FIS) – Spanish Health Research Fund Grant PI12/01291, and Instituto de Salud Carlos III (ISCIII), Grant PI15CIII/00028.S

INCEFA-PLUS Findings on Environmental Fatigue

INCEFA-PLUS is a five year project supported by the European Commission HORIZON2020 programme. The project concluded in October 2020. 16 organisations from across Europe have combined forces to deliver new experimental data which is being used to develop improved guidelines for assessment of environmental fatigue damage to ensure safe operation of nuclear power plants. Within INCEFA-PLUS, the effects of mean strain and stress, hold time, strain amplitude and surface finish on fatigue endurance of austenitic stainless steels in light water reactor environments have been studied experimentally. This document constitutes a Reference Book compiling the research developed within the INCEFA-PLUS Project. It provides a comprehensive overview of the tasks performed, and it also presents the background and the assumptions taken to develop the INCEFA-PLUS experimental and analytical works. It compiles and orders documents and contributions from INCEFA-PLUS partners.This project has received funding from the Euratom research and training program 2014-2018 under grant agreement No 662320

Thelypteris reticulata (L.) Proctor, nuevo registro pteridológico para la Guayana venezolana

Resumen. Se cita la presencia de Thelypteris reticulata (L.) Proctor en el estado Bolívar, como una nueva adición para la flora de la Guayana venezolana. Helecho que prospera en suelos pantanosos. Thelypteris reticulata (L.) Proctor new Pteridological record for Venezuelan Guayana Abstract. The presence Thelypteris reticulata (L.) Proctor in the Bolivar state is cited as a new addition to the flora of venezuelan Guayana, fern which flourish in march soil