105 research outputs found
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
A genome-wide identification and comparative analysis of the lentil MLO genes
Revista electrónica on linePowdery mildew is a widespread fungal plant disease that can cause significant losses in
many crops. Some MLO genes (Mildew resistance locus O) have proved to confer a durable
resistance to powdery mildew in several species. Resistance granted by the MLO gene family
members has prompted an increasing interest in characterizing these genes and implementing
their use in plant breeding. Lentil (Lens culinaris Medik.) is a widely grown food
legume almost exclusively consumed as dry seed with an average world production of 4.5
million tons. Powdery mildew causes severe losses on certain lentil cultivars under particular
environmental conditions. Data mining of the lentil CDC Redberry draft genome allowed to
identify up to 15 gene sequences with homology to known MLO genes, designated as
LcMLOs. Further characterization of these gene sequences and their deduced protein
sequences demonstrated conformity with key MLO protein characteristics such as the presence
of transmembrane and calmodulin binding domains, as well as that of other conserved
motifs. Phylogenetic and other comparative analyses revealed that LcMLO1 and LcMLO3
are the most likely gene orthologs related to powdery mildew response in other species,
sharing a high similarity with other known resistance genes of dicot species, such as pea
PsMLO1 and Medicago truncatula MtMLO1 and MtMLO3. Sets of primers were designed
as tools to PCR amplify the genomic sequences of LcMLO1 and LcMLO3, also to screen
lentil germplasm in search of resistance mutants. Primers were used to obtain the complete
sequences of these two genes in all of the six wild lentil relatives. Respective to each gene,
all Lens sequences shared a high similarity. Likewise, we used these primers to screen a
working collection of 58 cultivated and 23 wild lentil accessions in search of length polymorphisms
present in these two genes. All these data widen the insights on this gene family and
can be useful for breeding programs in lentil and close related species.S
Standardized and reproducible methodology for the comprehensive and systematic assessment of surgical resection margins during breast-conserving surgery for invasive breast cancer
<p>Abstract</p> <p>Background</p> <p>The primary goal of breast-conserving surgery (BCS) is to completely excise the tumor and achieve "adequate" or "negative" surgical resection margins while maintaining an acceptable level of postoperative cosmetic outcome. Nevertheless, precise determination of the adequacy of BCS has long been debated. In this regard, the aim of the current paper was to describe a standardized and reproducible methodology for comprehensive and systematic assessment of surgical resection margins during BCS.</p> <p>Methods</p> <p>Retrospective analysis of 204 BCS procedures performed for invasive breast cancer from August 2003 to June 2007, in which patients underwent a standard BCS resection and systematic sampling of nine standardized re-resection margins (superior, superior-medial, superior-lateral, medial, lateral, inferior, inferior-medial, inferior-lateral, and deep-posterior). Multiple variables (including patient, tumor, specimen, and follow-up variables) were evaluated.</p> <p>Results</p> <p>6.4% (13/204) of patients had positive BCS specimen margins (defined as tumor at inked edge of BCS specimen) and 4.4% (9/204) of patients had close margins (defined as tumor within 1 mm or less of inked edge but not at inked edge of BCS specimen). 11.8% (24/204) of patients had at least one re-resection margin containing additional disease, independent of the status of the BCS specimen margins. 7.1% (13/182) of patients with negative BCS specimen margins (defined as no tumor cells seen within 1 mm or less of inked edge of BCS specimen) had at least one re-resection margin containing additional disease. Thus, 54.2% (13/24) of patients with additional disease in a re-resection margin would not have been recognized by a standard BCS procedure alone (P < 0.001). The nine standardized resection margins represented only 26.8% of the volume of the BCS specimen and 32.6% of the surface area of the BCS specimen.</p> <p>Conclusion</p> <p>Our methodology accurately assesses the adequacy of surgical resection margins for determination of which individuals may need further resection to the affected breast in order to minimize the potential risk of local recurrence while attempting to limit the volume of additional breast tissue excised, as well as to determine which individuals are not realistically amendable to BCS and instead need a completion mastectomy to successfully remove multifocal disease.</p
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