A 10 GHz Quasi-Optical Grid Amplifier Using Integrated HBT Differential Pairs

We report the fabrication and testing of a 10 GHz grid amplifier utilizing sixteen GaAs chips each containing an HBT differential pair plus integral bias/feedback resistors. The overall amplifier consists of a 4x4 array of unit cells on an RT Duroid™ board having a relative permittivity of 2.2. Each unit cell consists of an emitter-coupled differential pair at the center, an input antenna which extends horizontally in both directions from the two base leads, an output antenna which extends vertically in both directions from the two collector leads, and high inductance bias lines. In operation, the active grid array is placed between a pair of crossed polarizers. The horizontally polarized input wave passes through the input polarizer and couples to the input leads. An amplified current then flows on the vertical leads, which radiate a vertically polarized amplified signal through the output polarizer. The polarizers serve dual functions, providing both input-output isolation as well as independent impedance matching for the input and output ports. The grid thus functions essentially as a free-space beam amplifier. Calculations indicate that output powers of several watts per square centimeter of grid area should be attainable with optimized structures

Circulating Strains of Human Respiratory Syncytial Virus in Central and South America

Human respiratory syncytial virus (HRSV) is a major cause of viral lower respiratory tract infections among infants and young children. HRSV strains vary genetically and antigenically and have been classified into two broad subgroups, A and B (HRSV-A and HRSV-B, respectively). To date, little is known about the circulating strains of HRSV in Latin America. We have evaluated the genetic diversity of 96 HRSV strains by sequencing a variable region of the G protein gene of isolates collected from 2007 to 2009 in Central and South America. Our results show the presence of the two antigenic subgroups of HRSV during this period with the majority belonging to the genotype HRSV-A2

Permeate microbiome reflects the biofilm microbial community in a gravity-driven woven-fiber microfiltration (WFMF) system for wastewater treatment

United Nations Sustainable Development Goal 6.3 aims to half the proportion of untreated wastewater and increase recycling and safe water reuse. Therefore, developing robust technologies to achieve these goals, specifically in low- to middle-income countries, is of concern. One such technology, gravity-driven woven-fiber microfiltration (WFMF) has been shown to be a reliable, low-cost, and versatile water treatment process. This study investigated a gravity-driven WFMF system for treating secondary wastewater. Given the significant role of the microbial community in biological treatment processes, this investigation focused on the inter-relationship between the microbiomes of the influent, biofilm, and permeate, while further examining the system's performance regarding microbial activity and permeate water quality. The WFMF system reached a quasi-steady state after approximately 10 days. The microbiome analysis, specifically beta diversity analysis, showed that the biofilm and permeate had similar microbiomes, proving a direct impact of the biofilm's microbial community on the permeate water quality. It also showed that the microbial community composition changed within the system. Alpha diversity analysis indicated that biofilm had higher richness and alpha diversity indices (e.g., OTUs and Shannon) than the influent. The system reduced the concentrations of fecal indicators Escherichia coli and Enterococcus spp. and the relative abundance of putative pathogens such as Legionella spp. Furthermore, it reduced microbial activity, as measured by intact cell counts and intracellular ATP, by 48.7% and 58.0%, respectively. Biofilm structure, investigated by various imaging techniques, including scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and optical coherence tomography (OCT), depicted a heterogeneous distribution over the membrane surface. The findings of this study underscore the role of the biofilm on the permeate's microbiome and, consequently, its impact on the permeate's biological stability and suitability for discharge and reuse. Thoroughly understanding microbial dynamics has implications for performance optimization, field implementation, and permeate discharge or reuse

Current threats faced by Neotropical parrot populations

Made available in DSpace on 2018-12-11T16:49:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-10-01Consejo Nacional de Investigaciones Científicas y TécnicasAgencia Nacional de Promoción Científica y TecnológicaPsittaciformes (parrots, cockatoos) are among the most endangered birds, with 31% of Neotropical species under threat. The drivers of this situation appear to be manifold and mainly of anthropogenic origin. However, this assessment is based on the last extensive consultation about the conservation situation of parrots carried out in the 1990s. Given the rapid development of anthropogenic threats, updated data are needed to strategize conservation actions. Using a population approach, we addressed this need through a wide-ranging consultation involving biologists, wildlife managers, government agencies and non-governmental conservation organizations. We gathered up-to-date information on threats affecting 192 populations of 96 Neotropical parrot species across 21 countries. Moreover, we investigated associations among current threats and population trends. Many populations were affected by multiple threats. Agriculture, Capture for the Pet Trade, Logging, each of them affected > 55% of the populations, suggesting a higher degree of risk than previously thought. In contrast to previous studies at the species level, our study showed that the threat most closely associated with decreasing population trends is now Capture for the local Pet Trade. Other threats associated with decreasing populations include Small-holder Farming, Rural Population Pressure, Nest Destruction by Poachers, Agro-industry Grazing, Small-holder Grazing, and Capture for the international Pet Trade. Conservation actions have been implemented on < 20% of populations. Our results highlight the importance of a population-level approach in revealing the extent of threats to wild populations. It is critical to increase the scope of conservation actions to reduce the capture of wild parrots for pets.Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable CONICET—Universidad Nacional del Centro de la Provincia de Buenos AiresJustus-Liebig-Universität Giessen Department of Animal Ecology and SystematicsTexas A&M University Schubot Exotic Bird Health Center Department of Veterinary Pathobiology College of Veterinary MedicineSociedade de Pesquisa em Vida Selvagem e Educação AmbientalUniversidade Federal de SergipePrograma Lapa Verde Centro Científico TropicalFacultad de Ciencias Naturales y Museo Universidad Nacional de La PlataArea de Conservación Pacífico Central ACOPAC Programa de Vida SilvestreWildlife Conservation SocietyAarhus UniversityGrupo de Ecología Conservación de Islas A.C. (GECI)University of California Department of Environment Science Policy & ManagementUniversidad Nacional Federico VillarrealUniversidade Federal de GoiásInstituto Venezolano de Investigaciones CientíficasProyecto Selva de Pino ParanáUnidos por las Guacamayas A. C.SELVA: Investigación para la conservación en el NeotrópicoInstituto Nacional de Tecnología AgropecuariaUniversity of BrasíliaUniversidade Federal da Paraíba Centro de Ciências Exatas e da NaturezaCentro Nacional de Pesquisa e Conservação de Aves Silvestres/ICMBioUniversidade Federal do Pará Instituto de Ciências BiológicasGuyra ParaguayUniversity of Colorado Department of Integrative BiologyThe World Parrot TrustBirdsCaribbeanFundacion del RioUniversitat de BarcelonaSociedad Conservacionista Audubon de VenezuelaUniversidad de Sancti Spíritus ¨José Martí Pérez¨Estación Biológica de Doñana CSICFundación Pro-BosqueCompañeros en Vuelo PIF-SVInstituto de Investigaciones Marinas y Costeras CONICET—Universidad Nacional de Mar del PlataUniversity of North Texas Biological SciencesOne Earth ConservationInstituto Espaço SilvestreUniversidade do Estado do AmazonasNational Aviary Conservation and Field ResearchUniversity of Cape TownBirdlife InternationalPaso PacíficoUniversidade de Passo FundoBiola UniversityMinisterio del Ambiente y los Recursos Naturales (MARENA)Universidad Michoacana de San Nicolas de HidalgoFundação Universidade Federal de Mato Grosso do SulAQUASISFundación Botánica y Zoológica de BarranquillaProvitaCIT Jujuy CONICET—UNJuFundación de Ciencias para el Estudio y la Conservación de la Biodiversidad (INCEBIO)UNESP Instituto de Biociências de BotucatuUniversidad Nacional Autónoma de México Estación Biología Chamela Instituto de BiologíaVinculación Interdisciplinaria para el Desarrollo Ambiental y lo SocialMesserli Research Institute University of Veterinary MedicineMuseo Noel Kempff MercadoGobierno Autónomo Departamental de Santa CruzUniversidad Autónoma de SinaloaMuseu de Zoologia da Universidade de Sao Paulo (MZUSP)University of Freiburg Evolutionary Biology and Animal EcologyMuseu de História Natural Capão da ImbuiaFundação Neotropica do BrasilCEMAVE: Centro Nacional de Pesquisa para a Conservação das Aves SilvestresCORBIDIAsociación Fauna ForeverUniversity of San Francisco Xavier de ChuquisacaUniversidad Nacional Autónoma de México Museo de Zoología Facultad de CienciasU.S. Fish and Wildlife Service Puerto Rican Parrot Recovery ProgramEcho Parrots and PeopleCátedra de Ecología General y Recursos Naturales Universidad Nacional Arturo JauretcheFundación para la Investigación y Conservación de los Loros en Bolivia (CLB)Instituto de Bio y Geociencias del NOA CONICETLaboratorio Nacional de Análisis y Síntesis Ecológica Universidad Nacional Autónoma de MéxicoDepto. de Estudios Ambientales Universidad Simón BolívarUNESP Instituto de Biociências de BotucatuConsejo Nacional de Investigaciones Científicas y Técnicas: CONICET-PIP 112-201501-0598Agencia Nacional de Promoción Científica y Tecnológica: FONCyT-PICT 2015-228