27 research outputs found
PteridĂłfitas da Serra Negra, Minas Gerais, Brasil
Este trabalho apresenta uma lista de espĂ©cies de pteridĂłfitas que ocorrem na Serra Negra, Minas Gerais. A serra estĂĄ inserida no complexo da Serra da Mantiqueira situada entre Rio Preto, Lima Duarte, Santa BĂĄrbara do Monte Verde e Olaria, tendo seus limites nos pontos 21Âș58'11"S 43Âș53'21" W, 22Âș01'46,4" S 43Âș52'31,5" W, 21Âș58'21,4" S 43Âș50'06,5" W e 21Âș58'53" S 43Âș56'08" W. A vegetação da serra Ă© formada por um mosaico de fitofisionomias, sendo encontradas formaçÔes florestais (florestas ombrĂłfilas e semidecĂduas) e campestres (campos rupestres). O inventĂĄrio florĂstico foi realizado entre os anos de 2003 e 2008, em excursĂ”es mensais para coleta de amostras e registro de dados. Na serra foram registradas 209 tĂĄxons infragenĂ©ricos distribuĂdas em 24 famĂlias e 75 gĂȘneros. As famĂlias com maior nĂșmero de espĂ©cies foram Polypodiaceae (40), Dryopteridaceae (33) e Pteridaceae (25). A maioria das espĂ©cies (109) foi encontrada ocorrendo exclusivamente no interior de floresta. Em relação ao hĂĄbito, 69 espĂ©cies foram encontradas exclusivamente como terrestres, 37 como rupĂcolas ou terrestres e 32 exclusivamente epĂfitas. Este trabalho revela uma elevada riqueza de pteridĂłfitas na regiĂŁo e indica a importĂąncia de estudos desta natureza na conservação e manejo das pteridĂłfitas em Minas Gerais.This work presents an inventory of pteridophyte species that occur in the Serra Negra, of Minas Gerais. The area is part of the Mantiqueira Range, and is situated between the coordinates 21Âș58'11"S 43Âș53'21" W, 22Âș01'4.4" S, 43Âș52'31.5" W, 21Âș58'21.4" S, 43Âș50'06.5" W and 21Âș58'53" S, 43Âș56'08" W. The vegetation in the Serra Negra is characterized by a mosaic of different phytophysiognomies, divided into forests (evergreen and seasonal semideciduous forests) and open formations (rocky grasslands). The inventory was carried out from 2003 to 2008, during monthly excursions to collect botanical material and data in the study area. A total of 209 species, distributed in 24 families and 75 genera, were recorded. The families with the highest number of species were Polypodiaceae (40), Dryopteridaceae (33) and Pteridaceae (25). More than the half (110) of the inventoried species were recorded exclusively in the forests formations. Sixty-nine species were terrestrial, 37 were saxicolous or terrestrial and 32 were epiphytes. This work shows that this region is rich in ferns and reveals the importance of this kind of study for conservation and management of pteridophytes in the state of Minas Gerais
Measurement of the lifetime of the meson using the decay mode
The difference in total widths between the and mesons is
measured using 3.0fb of data collected by the LHCb experiment in 7 and 8
TeV centre-of-mass energy proton-proton collisions at the LHC. Through the
study of the time evolution of and
decays, the width difference is measured to be
where the first uncertainty is statistical and the second
systematic. The known lifetime of the meson is used to convert this to a
precise measurement of the lifetime,
where the first uncertainty is
statistical and the second systematic.Comment: 19 pagers, 3 figure