4,950 research outputs found
Diversidade de rizóbios em áreas revegetadas após a mineração de bauxita.
A contribuição da diversidade dos rizóbios para manutenção da diversidade e funcionalidade de ecossistemas naturais tem sido pouco estudada. Neste trabalho objetivou-se avaliar a diversidade de rizóbios em áreas revegetadas em diferentes épocas. Utilizou-se siratro e mimosa como plantas-isca e as ferramentas PCR-RFLP, sequencimanto e BOX-PCR. Observou-se que as áreas de maior diversidade foram as revegetadas há mais tempo e as áreas revegetadas com plantio da leguminosa Acacia mangium e, que isolados proximamente relacionados ao gênero Bradyrhizobium foram os mais abundantes
Caracterização fenotípica e genotípica de rizóbios em áreas de mineração de bauxita com diferentes idades de revegetação.
Ferramentas para caracterização fenotípica e genotípica de bactérias fixadoras de nitrogênio tornaram-se valiosas para os ecólogos de microrganismos devido ao seu poder discriminatório e estas vêm sendo utilizadas com sucesso para a caracterização e avaliação da diversidade genética destes microrganismosno solo. O objetivo deste trabalho foi caracterizar fenotípica e genotipicamente e avaliar a diversidade de isolados de nódulos de siratro provenientes de áreas com diferentes idades de revegetação após a mineração de bauxita. Amostras de solo foram coletadas em áreas revegetadas após a atividade de mineração de bauxita da Mineração Rio do Norte (MRN) em talhões de reflorestamento que foram revegetados em diferentes anos, compondo assim uma cronossequência de revegetação entre 1981 e 2006. Estas amostras foram distribuídas em vasos com capacidade de 1 kg e semeou-se Macroptilium atropurpureum. Os sessenta e sete isolados obtidos foram purificados e avaliados quanto às diversas características fenotípicas e através do BOX-PCR. Com base na caracterização fenotípica foi construído um dendrograma utilizando o programa estatístico R. A extração do DNA genômico dos sessenta e sete isolados foi realizada utilizando-se o kit Promega após prévio cultivo em meio YMA e as reações de amplificação realizadas segundo Kaschuk et al., 2006 utilizando o primer BOX A1R. Os perfis de bandas gerados pelo BOX-PCR foram utilizados no programa Gel Compar 2.0 Applied Maths para construção de um dendrograma de similaridade (coeficiente Jaccard e o método de agrupamento UPGMA). Observou-se elevada diversidade entre os isolados, que se distribuíram por 15 grupos na análise de BOX. Não foi observado efeito do ano de revegetação sobre a diversidade de isolados de nódulos de Macroptilium atropurpureum.Resumo 1452-1
“Western Mediterranean” (WM) broad band network: permanent seismic monitoring at the Ibero-Maghrebian region
The “Ibero-Maghrebian” region, a western part of the Eurasia-Africa plate boundary, is a broad deformation area without a well defined plate boundary line, comprising the Southern part of the Iberian Peninsula, the Northwestern part of Africa, the Gulf of Cadiz and the Alboran Sea, with a convergence between Iberia and Africa at some mm/year (Nuvel-1A model, DeMets et al, 1994) in a NNW-SSE direction, and a dif- ferential motion at Alboran Sea area (Buforn et al, 1995). Although seismic activity is characterized by a low to moderate magnitude and shallow depth earthquakes, big events are also well documented, among others: Lisbon earthquake (1755, I0= X), Gulf of Cadiz (1969, Ms= 8.1), or, more recently Bourmedes (2003, Mw= 7.1), some them with an associated tsunami, like Lisbon or Bourmedes earthquakes. An interme- diate seismic activity is also clearly registered from Gulf of Cadiz to mid Alboran Sea (Martin Davila and Pazos, 2003), and very deep earthquakes (h> 650 km) have been registered at Granada basin (1954, M= 7.0).
In order to better study the seismic characteristics of this area, from 1996 on, ROA and the University Complutense of Madrid (UCM), with the collaboration of Geo- forschungZentrum of Potsdam (GFZ), have deployed a broad band seismic net with stations located at Southern Spain and Spanish possessions located Northern Africa,
mainly surrounding the Alboran Sea, complementing the previously installed ROA SP and LP stations. This net has been named as “Western Mediterranean net” (WM FDSN code). As net was evolving, new Institutes and stations joined WM net, such a way at present is formed by ten stations located at: San Fernando (SFS), Málaga (MALA), Cartagena (CART), and Evora (UEVO, University of Evora, Portugal) at Iberian peninsula, Mahón (MAHO) at Minorca island, three stations at Melilla (MELI), Peñón de Vélez-Gomera (PVLZ), and Ceuta (CEU) at Spanish villages located Northern Africa in South Alboran Sea area, and Averroes (AVE) and Ifrane (IFR) installed at Morocco mainland as a joined effort among ISRABAT (Institut Scientifique, Univer- sité Mohammed V), ROA and UCM. Most stations are collocated with permanent geodetic GPS stations (Gárate et al, 2004). Next future plans include the installation of five stations by U. Evora at Southern Portugal area, a new station at Morocco by ISRABAT, ROA and UCM and also a new station at Oran (Algeria), as a collaboration among Université d’Oran (Algeria), ROA and UCM. All them will be associated to WM net.
All WM network stations include Streckeisen STS-2 sensor, a Quanterra or Earth Data digitizer, and a SeiscomP process system (Heinloo, 2004), and all them are available in real time via phone modem or Internet, except PVLZ and CEU, which will be in short.
In this work, partly funded by the Spanish Ministry of Education and Science (MEC) through the project REN2006-10311-C03-01/02 (RISTE), we will present the present status, the next future plans and some related activities of WM net
Diversidade de fungos micorrízicos arbusculares em áreas revegetadas após a mineração de bauxita.
A contribuição da diversidade dos FMAs para manutenção da diversidade e funcionalidade de ecossistemas naturais tem sido pouco estudada. Neste trabalho objetivou-se avaliar a diversidade de FMAs em áreas revegetadas em diferentes momentos. Com base na morfologia de esporos 13 espécies distintas foram encontradas, com predomínio de espécies dos gêneros Glomus e Acaulospora. Glomus macrocarpum foi a espécies mais freqüente e abundante e as parcelas das áreas revegetadas nos anos de 1985A1, 1998A1, 2002-1, 2002A1, 2004FP e 2006-1 apresentaram os maiores valores do índice de diversidade Shannon. Não foi observada relação entre o tempo de revegtação e a diversidade de FMAs
Assessment of DNA extraction methods for detection of arbuscular mycorrhizal fungi in plant roots by nested-PCR.
Open and hidden charm in proton-nucleus and heavy-ion collisions
We review the collectivity and the suppression pattern of charmed mesons -
produced in proton-nucleus and nucleus-nucleus collisions at SPS (158 AGeV) and
RHIC energies (21 ATeV) - in comparison to dynamical and thermal models. In
particular, we examine the charmonium `melting' and the `comover dissociation'
scenarios - implemented in a microscopic transport approach - in comparison to
the available data from the SPS and RHIC. The analysis shows that the dynamics
of c, c-bar quarks at RHIC are dominated by partonic or `pre-hadronic'
interactions in the strongly coupled plasma stage. Both the `charmonium
melting' and the hadronic `comover absorption and recreation model' are found,
however, to be compatible with the experimental observation at SPS energies;
the experimental ratio of Psi'/J/Psi versus centrality clearly favors the
`hadronic comover' scenario. We find that the collective flow of charm in the
purely hadronic Hadron-String Dynamics (HSD) transport appears compatible with
the data at SPS energies, but substantially underestimates the data at top RHIC
energies. Thus, the large elliptic flow v2 of D-mesons and the low R_AA(p_T) of
J/Psi seen experimentally have to be attributed to early interactions of
non-hadronic degrees of freedom. Simultaneously, we observe that non-hadronic
interactions are mandatory in order to describe the narrowing of the J/Psi
rapidity distribution from pp to central Au+Au collisions at the top RHIC
energy. We demonstrate additionally that the strong quenching of low-pT J/Psi's
in central Au+Au collisions indicates that a large fraction of final J/Psi
mesons is created by a coalescence mechanism close to the phase boundary.
Throughout this review we, furthermore, provide predictions for charm
observables from Au+Au collisions at FAIR energies of 25-35 AGeV.Comment: review for Int. J. Mod. Phys. E, 75 pages, 50 figure
Parasites in Loricariidae from Brazil: checklist and new records for fish from the Brazilian Amazon.
The aim of this study was to investigate the parasites fauna of Ancistrus leucostictus, Hypostomus ventromaculatus, Ancistrus sp. and Hemiancistrus sp. from the Igarapé Fortaleza River (Amapá State, Brazil), besides making a checklist of the parasite species in Loricariidae from Brazil. A total of 53 fishes were collected from November 2013 to August 2014. In the hosts, a total of 1,559 parasites of seven taxa were collected: Unilatus unilatus, Trinigyrus mourei, undetermined metacercariae, Genarchella gernachella, Raphidascaris (Sprentascaris) sp., Gorythocephalus elongorchis and Proteocephalus sp. Ectoparasite species were frequent in the examined Loricariidae species, which also had larval stages of endoparasites. The hosts with the highest sampled number, H. ventromaculatus and Ancistrus sp., had the highest parasite species richness. Loricariidae species from Brazil are parasitized by species of Protozoa, Monogenea, Nematoda, Digenea, Acantocephala, Cestoda, Crustacea and Hirudinea, but monogeneans, digeneans and nematodes were the predominant taxa
Rhizobial characterization in revegetated areas after bauxite mining.
Little is known regarding how the increased diversity of nitrogen-fixing bacteria contributesto the productivity and diversity of plants in complex communities. However, some authorshave shown that the presence of a diverse group of nodulating bacteria is required for dif-ferent plant species to coexist. A better understanding of the plant symbiotic organismdiversity role in natural ecosystems can be extremely useful to define recovery strategies ofenvironments that were degraded by human activities. This study used ARDRA, BOX-PCRfingerprinting and sequencing of the 16S rDNA gene to assess the diversity of root nodulenitrogen-fixing bacteria in former bauxite mining areas that were replanted in 1981, 1985,1993, 1998, 2004 and 2006 and in a native forest. Among the 12 isolates for which the 16SrDNA gene was partially sequenced, eight, three and one isolate(s) presented similarity withsequences of the genera Bradyrhizobium, Rhizobium and Mesorhizobium, respectively. The rich-ness, Shannon and evenness indices were the highest in the area that was replanted theearliest (1981) and the lowest in the area that was replanted most recently (2006)
Efeito da extrusão sobre a densidade absoluta, aparente e índice de expansão volumétrica em produtos extrudados à base de grits de milho e gergelim em grão.
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