Two QTLs govern the resistance to Sclerotinia minor in an interspecific peanut RIL population

Sclerotinia blight is a soilborne disease caused by Sclerotinia minor Jagger and can produce severe decrease in yield. Cultural management strategies and chemical treatment are not completely effective; therefore, growing peanut-resistant varieties is likely to be the most effective control method for this disease. Sclerotinia blight resistance has been identified in wild Arachis species and further transferred to peanut elite cultivars. To identify the genome regions conferring Sclerotinia blight resistance within a tetraploid genetic background, this study evaluated a population of recombinant inbred lines (RIL) with introgressed genes from three wild diploid species: A. cardenasii, A. correntina, and A. batizocoi. Two consistent quantitative trait loci (QTLs), qSbIA04 and qSbIB04 located on chromosomes A04 and B04, respectively, were identified. The QTL qSbIA04 was mapped at 56.39 cM explaining 29% of the phenotypic variance and qSbIB04 was mapped at 13.38 cM explaining 22% of the overall phenotypic variance

Symbolic dynamics for the NN-centre problem at negative energies

We consider the planar $N$-centre problem, with homogeneous potentials of degree -\a<0, \a \in [1,2). We prove the existence of infinitely many collisions-free periodic solutions with negative and small energy, for any distribution of the centres inside a compact set. The proof is based upon topological, variational and geometric arguments. The existence result allows to characterize the associated dynamical system with a symbolic dynamics, where the symbols are the partitions of the $N$ centres in two non-empty sets

Etiologia de manchas de sementes de cultivares de arroz de sequeiro no Centro-Oeste brasileiro.

O presente trabalho teve o objetivo de conhecer os fungos que mancham sementes de arroz, estudando a importância de cada um, sua frequência e nível de incidência, baseando-se na correlação da quantidade de cada fungo com a quantidade de mancha de semente de arroz de sequeiro do Centro-Oeste brasileiro

Charm in nuclear reactions in sqrt(s)=17 and 19 GeV

Consequences resulting from the D Dbar excess derived indirectly by the NA50 experiment in S+U and Pb+Pb collisions at sqrt(s)=19, 17 GeV, relevant for the identification of the QCD phase transition in these collisions, are discussed. The dependence of open and closed charm yields in Pb+Pb collisions on the number of participating nucleons (N) indicates non thermal charm production and J/Psi dissociation, stronger than the absorption seen in any other elementary hadron. The J/Psi in central Pb+Pb collisions could originate dominantly from c cbar pair coalescence out of a hadronizing quark and gluon environment. Furthermore, the J/Psi appears to be suppressed in S+U collisions at sqrt(s)=19 GeV, as opposed to current interpretations. A significant change in the (J/Psi)/D Dbar ratio as well as in the number density of kaons is observed above energy density approx. 1 GeV/fm^3, suggesting a change of phase at this energy density, and underlining the importance of direct open charm measurements.Comment: (23 pages, 7 figures

The definitive management of Hirschsprung's disease with the endorectal pull-through procedure

From 1 July 1974 to 31 August 1985, 99 patients with Hirschsprung's disease were treated at the University of Michigan Mott Children's Hospital; 75 were initially diagnosed and treated at our institution. Of these 75 patients, 55 had standard rectosigmoid disease and 20 had long-segment disease. The endorectal pull-through (ERPT) procedure was used consecutively in 73 of the 75 patients; the other two children died, one because of total intestinal aganglionosis and the other due to severe congenital anomalies, prior to a definitive procedure. Of the 24 patients referred by other institutions, 12 underwent repeat pull-through procedures and 12 required lesser operations to deal with the complications of prior procedures. There were no postoperative deaths and no permanent enterostomies among the 73 consecutive ERPT patients. The follow-up in this series ranges from 4 months to 10 years, and all patients have fecal continence with an average of 3–4 stools daily. Our treatment plan involves the use of suction rectal biopsy for diagnosis and leveling colostomy in the neonatal period. An endorectal pull-through procedure is then carried out between 8 months and 1 year of age. The excellent functional results, 0% operative mortality, low morbidity, and technical ease of performing the ERPT underscore our enthusiasm for continued use of this procedure in Hirschsprung's disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47147/1/383_2004_Article_BF00166867.pd

Anomalous J/ψJ/\psi suppression in Pb-Pb interactions at 158 GeV per nucleon

The Drell-Yan and J/psi cross-sections measured in Pb-Pb collisions are compared with the values extrapolated from the results obtained in proton and light ion induced reactions. While the Drell-Yan production exhibits the normal expected behaviour, the yield of J/psi in Pb-Pb interactions is abnormally low, as it lies 9 standard deviations below the expected value. Moreover, the departure from the expected behaviour increases significantly from peripheral to central collisions. (C) 1997 Elsevier Science B.V