Mancha areolada de Thanatephorus da seringueira na Amazônia: identificação filogenética e variação genética em populações do patógeno.

A mancha areolada de Thanatephorus é uma das doenças mais importantes da seringueira (Hevea brasiliensis) na Amazônia. Apesar disso, questão importante sobre o real posicionamento filogenético deste patógeno ainda não foi respondida. Neste estudo, nós analisamos os padrões de variação genética em seqüências da região ITS-5.8S do rDNA de uma população de T. cucumeris (fase assexuada = Rhizoctonia solani AG 2-2) associado à mancha areolada da seringueira amostrada em Belém (Pará), Manaus (Amazonas) e Xapuri/Rio Branco (Acre) na Amazônia, e comparando-a filogeneticamente com membros do complexo AG 2 descritos mundialmente. Este estudo representa um passo importante para revelar a etiologia da fase assexuada de T.cucumeris da seringueira

QCD coherence in deep inelastic scattering at small x at HERA

QCD coherence effects in initial state radiation at small x in deep inelastic scattering in HERA kinematics are studied with the help of the Monte Carlo model SMALLX. Theoretical assumptions based on the CCFM evolution equation are reviewed and the basic properties of the partonic final states are investigated. The results are compared with those obtained in the conventional DGLAP evolution scheme.Comment: 23 pages, latex, 9 ps figures included. One reference added and citation in the paper improve

Corrections to Angular Ordering in Multiple Hadroprodroproduction

One of the key ideas in describing the multiparticle production at high energies in the perturbative QCD is the angular ordering in successive soft-gluon emission. We analyse the angular distribution of particles in a jet, and investigate the corrections to the angular ordering. At a small angle from the jet direction, the angular ordering is exact at the next-to-leading order. At a large angle, the angular ordering overestimates the angular particle density by a factor $(1-\gamma\ln \cos^2(\theta/2))$, where $\gamma$ is the anomalous dimension of the multiplicity. The $O(\gamma)$ correction restores the boost invariance of the cross section.Comment: Latex fil

Systemic immune responses associated to Haemonchus contortus resistance in a resistant Brazilian sheep breed (Morada Nova).

Haemonchus contortus infection is the greatest cause of economic losses in sheep production worldwide