8 research outputs found

    Systematics, taxonomy and floristics of Brazilian Rubiaceae: an overview about the current status and future challenges

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    Pollen morphology of Rubiaceae Juss. species occurring in an area of caatinga (dryland) vegetation in Bahia State, Brazil

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    The palynology of the following 16 species of Rubiaceae, from Brejinho das Amestistas, was investigated: Coccocypselum hirsutum Bartl. ex DC., Cordiera rigida Kuntze, Coutarea hexandra K.Schum., Declieuxia fruticosa Kuntze, Diodella apiculata (Willd. ex Roem. & Schult.) Delprete, D. radula (Willd. ex Roem. & Schult.) Delprete, D. teres Small., Emmeorhiza umbellata K.Schum., Leptoscela ruellioides Hook. f., Mitracarpus baturitensis Sucre., Mitracarpus villosus Cham. & Schltdl., Palicourea rigida Kunth, Psyllocarpus asparagoides Mart., Richardia grandiflora Steud., Staelia aurea K. Schum., and Staelia galioides DC. The pollen grains were acetolysed to and their morphological characters were analyzed using light and scanning electron microscopy. They varied in size from small to large; were suboblate to subprolate; inaperturate (P. rigida), colpate and colporate in the remaining species, with an aperture number that varied from three to several. The exines were microreticulate in most species, reticulate (C. hirsutum, C. rigida and P. rigida), bireticulate (D. fruticosa), microechinate-perforated (C. hexandra), echinate-granulate (R. grandiflora), echinate-granulate-perforate (D. apiculata and D. teres), and psilate (P. asparagoides). Based on the results, palynological data can be used to distinguish these species

    Palinologia do componente herbáceo na atmosfera de Caxias do Sul, RS, Brasil Palinology of the herbaceous component in the atmosphere of Caxias do Sul, Rio Grande do Sul State, Brazil

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    Este estudo foi realizado na cidade de Caxias do Sul de 1/janeiro/2001 a 31/dezembro/2002 e objetivou identificar os tipos polínicos de táxons herbáceos presentes na atmosfera e suas oscilações sazonais. A cidade está localizada na Encosta Superior Nordeste, Estado do Rio Grande do Sul. Seu clima é tropical pluvisazonal e apresenta três diferentes tipos de vegetação: Floresta Ombrófila Mista, Floresta Decidual e Campo. O monitoramento polínico foi realizado utilizando o captador volumétrico de sucção Burkard®, instalado no topo do Hospital Geral a uma altura aproximada de 20 m. Durante o período de estudo foram identificados 40 tipos polínicos, sendo 11 de táxons herbáceos, representando 23,22% do total de grãos coletados. A concentração máxima das táxons herbáceos registrou-se nos meses de outubro e novembro. O tipo polínico Poaceae R.Brown apresentou a maior incidência, seguido por Cyperaceae Juss., Plantago L., Amaranthus L., Rumex L., Iridaceae Juss., Brassicaceae Burnett, Apiaceae Lindl., Alternanthera Forssk., Convolvulaceae Juss. e Caryophyllaceae Juss.<br>This study was carried out in the city of Caxias do Sul, from January 1, 2001 to December 31, 2002 and aimed to identify pollen types and seasonal fluctuation of herbaceous taxa in the atmosphere. The city is located on the Upper Northeast Slopes in Rio Grande do Sul State. The climate is tropical with seasonal rainfall and there are three different types of vegetation: mixed ombrophilous forest, deciduous forest and grassland. Pollen monitoring was done with a Burkard® volumetric spore-trap sampler placed on top of the Hospital Geral, about 20m above ground level. During the study period 40 pollen types were identified, 11 from herbaceous taxa, which represents 23.22% of the total number of grains collected. Maximum concentration of herbaceous taxa was registered in October and November. The Poaceae R.Brown pollen type had the highest incidence, followed by Cyperaceae Juss., Plantago L., Amaranthus L., Rumex L., Iridaceae Juss., Brassicaceae Burnett, Apiaceae Lindl., Alternanthera Forssk., Convolvulaceae Juss. and Caryophyllaceae Juss

    Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

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    This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena
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