Los minadores de hojas son insectos cuyas larvas viven y se alimentan dentro de las hojas, consumiendo el mesófilo sin dañar la epidermis foliar. Varias especies son consideradas serias plagas de ...cultivos intensivos, hortícolas y ornamentales. Entre las fuentes de mortalidad más importantes para este gremio de fitófagos se citan a los enemigos naturales, de los que se destacan los parasitoides como el grupo más efectivo y mejor representado. Este artículo proporciona un resumen actualizado de la información disponible sobre parasitoides de minadores de hojas en relación al manejo de plagas. Por ser generalistas, los parasitoides de minadores de hojas pueden incluir rápidamente en su rango alimenticio a especies introducidas, muchas veces lográndose un control efectivo luego de unos pocos años de establecida la plaga. Control biológico clásico y aumentativo son estrategias ampliamente usadas para regular las poblaciones de minadores de hojas plaga. Numerosos estudios abordan la compatibilidad del uso de parasitoides con control químico y cultural. Si bien la mayoría de los insecticidas convencionales poseen efectos adversos para los parasitoides, otros serían compatibles con el control biológico. Se conoce que la combinación de diversas estrategias de control en programas de manejo integrado de plagas ha resultado efectivo contra minador de hojas plaga. Sin embargo, los efectos de prácticas culturales que podrían favorecer las poblaciones de parasitoides han sido escasamente estudiados
A Higgs particle produced in association with a Z boson and decaying into two photons is searched for in the data collected by the L3 experiment at LEP. All possible decay modes of the Z boson are ...investigated. No signal is observed in 447.5 pb−1 of data recorded at centre-of-mass energies from 192 GeV up to 209 GeV. Limits on the branching fraction of the Higgs boson decay into two photons as a function of the Higgs mass are derived. A lower limit on the mass of a fermiophobic Higgs boson is set at 105.4 GeV at 95% confidence level.
The reaction e+e−→e+e−pp̄ is studied with the L3 detector at LEP. The analysis is based on data collected at e+e− center-of-mass energies from 183 GeV to 209 GeV, corresponding to an integrated ...luminosity of 667 pb−1. The γγ→pp̄ differential cross section is measured in the range of the two-photon center-of-mass energy from 2.1 to 4.5 GeV. The results are compared to the predictions of the three-quark and quark–diquark models.
A Higgs particle produced in association with a Z boson and decaying into weak boson pairs is searched for in 336.4 pb−1 of data collected by the L3 experiment at LEP at centre-of-mass energies from ...200 to 209 GeV. Limits on the branching fraction of the Higgs boson decay into two weak bosons as a function of the Higgs mass are derived. These results are combined with the L3 search for a Higgs boson decaying to photon pairs. A Higgs produced with a Standard Model e+e−→Zh cross section and decaying only into electroweak boson pairs is excluded at 95% CL for a mass below 107 GeV.
Inclusive charged hadron production, e+e−→e+e−h±X, is studied using 414 pb−1 of data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 202 GeV. Single particle ...inclusive differential cross sections are measured as a function of the particle transverse momentum, pt, and pseudo-rapidity, η. For pt⩽1.5 GeV, the data are well described by an exponential, typical of soft hadronic processes. For higher pt, the onset of perturbative QCD processes is observed. The π± production cross section for pt>5 GeV is much higher than the NLO QCD predictions.
Bose–Einstein correlations of both neutral and like-sign charged pion pairs are measured in a sample of 2 million hadronic Z decays collected with the L3 detector at LEP. The analysis is performed in ...the four-momentum difference range 300 MeV<Q<2 GeV. The radius of the neutral pion source is found to be smaller than that of charged pions. This result is in qualitative agreement with the string fragmentation model.
Double-tag events in two-photon collisions are studied using the L3 detector at LEP centre-of-mass energies from s=189 GeV to 209 GeV. The cross sections of the e+e−→e+e−hadrons and γ∗γ∗→hadrons ...processes are measured as a function of the product of the photon virtualities, Q2=Q21Q22, of the two-photon mass, Wγγ, and of the variable Y=ln(W2γγ/Q2). The average photon virtuality is 〈Q21〉=〈Q22〉=16 GeV2. The results are in agreement with next-to-leading order calculations for the process γ∗γ∗→qq̄ in the interval 2⩽Y⩽5. An excess is observed in the interval 5<Y⩽7, corresponding to Wγγ greater than 40 GeV. This may be interpreted as a contribution of resolved photon QCD processes or the onset of BFKL phenomena.
The Large Hadron Collider at CERN will start data acquisition in 2007. The ATLAS (A Toroidal LHC Apparatus) experiment is preparing for the data handling and analysis via a series of Data Challenges ...and production exercises to validate its computing model and to provide useful samples of data for detector and physics studies. The last Data Challenge, begun in June 2004 and ended in early 2005, was the first performed completely in a Grid environment. Immediately afterwards, a new production activity was necessary in order to provide the event samples for the ATLAS physics workshop, taking place in June 2005 in Rome. This exercise offered a unique opportunity to estimate the reached improvements and to continue the validation of the computing model. In this paper we discuss the experience of the "Rome production" on the LHC Computing Grid infrastructure, describing the achievements, the improvements with respect to the previous Data Challenge and the problems observed, together with the lessons learned and future plans
Events from the e+e−→Zγ process with hard initial-state radiation collected with the L3 detector at centre-of-mass energies between 183 and 209 GeV are used to measure the mass of the Z boson. Decays ...of the Z boson into hadrons or muon pairs are considered and the Z mass is determined to be 91.272±0.032(stat)±0.033(syst) GeV, in agreement with the value measured at the Z resonance. Alternatively, assuming this measured value of the Z mass, the method determines the LEP centre-of-mass energy, found to be 175±68(stat)±68(syst) MeV lower than the nominal value.
We measure three-particle Bose–Einstein correlations in hadronic Z decay with the L3 detector at LEP. Genuine three-particle Bose–Einstein correlations are observed. By comparing two- and ...three-particle correlations we find that the data are consistent with fully incoherent pion production.
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