1,398 research outputs found
Growth and yield of tomato crop under subsurface drip irrigation treated with different Trifluralin doses
[SPA] El trabajo pretende evaluar el crecimiento y rendimiento de un cultivo de tomate
atendiendo al tipo del sistema de riego localizado: subterráneo (SDI) y superficial (CDI),
sustrato y dosis y modo de aplicación de Trifluralina (TFN).Este trabajo consta de dos
partes: la primera compara ambos sistemas de riego, evaluando la acción de TFN y su
eficacia en la prevención de la intrusión radicular. Los resultados mostraron que SDI con
una dosis apropiada de TFN generó mayor producción que CDI. La segunda parte evaluó la
implicación de diferentes tipos de substratos, dosis de TFN y método de aplicación de TFN
sobre el rendimiento y crecimiento de un cultivo de tomate bajo SDI. Los resultados
sugieren que el incremento en la dosis de TFN previene la intrusión radicular pero reduce
el potencial productivo del cultivo. Este hecho fue mayor en suelos con baja capacidad de
retención de agua y TFN, donde el riesgo de intrusión radicular es reducido, por lo que
dosis altas de TFN tiene una acción nociva sobre la producción.
[ENG] The study evaluates the influence of the irrigation system, the soil substrate, the dosage
and application of the herbicide trifluralin (TFN) in the growth and yield of tomato crops.
This work comprised two differentiated parts. The first compares both systems irrigation,
evaluating TFN action and its efficacy preventing from root intrusion. Results showed that
SDI with an appropriate dosage of TFN to prevent from root intrusion, yielded higher
production that CDI. The second part assessed the implication of different soil substrates,
TFN dosage and application method in the yield and growth of tomato crops under SDI.
Results suggested that an increasing dose of TFN prevents drippers from root intrusion but
reduced crop productivity. This fact was enhanced in soils with low water retention
capacity (sand), where the risk of root intrusion was lower, so high doses of TFN had a
harmful rather than a beneficial effect on crop production.Trabajo financiado por el Proyecto de Investigación “Desarrollo técnico y agronómico del
riego localizado subterráneo como alternativa para aumentar la eficiencia hídrica en diferentes
sistemas agrícolas. 480/02PA” entre la UPCT y Sistema Azud S. A
Subsurface drip irrigation vs. surface drip irrigation in tomato
[SPA] Las motivaciones de este trabajo se fundamentan en la necesidad de caracterizar y valorar la utilidad de los sistemas de riego localizado subterráneo (RLSub) y la medida en la que estos se ven modulados por el diseño agronómico e hidráulico del sistema, y de forma aún más significativa por la aparición de obstrucciones en los emisores enterrados, y más particularmente las debidas a la intrusión radicular, en este sentido, es muy importante caracterizar las variables que las modulan para asegurar la viabilidad y eficiencia de este sistema de riego. Se pretende estudiar las diferencias en desarrollo y productividad con distintos tipos de sustrato, y distintos tipos de sistema de riego, siendo uno de ellos el RLSub, manejado con diferentes tratamientos del herbicida Trifluralina (TFN). Se evaluará la respuesta del cultivo atendiendo al tipo de sistema de riego empleado en términos de eficiencia en el uso del agua y valorando la respuesta a la aplicación de TFN sobre éstos y sobre la aparición de intrusión radicular de distintos tipos de emisores.
[ENG] The motivations of this paper are based on the need to characterize and assess the utility of subsurface drip irrigation (RLSub) and the extent to which these are modulated by the agronomic and hydraulic system design, and even more significant for the occurrence of clogging in the buried emitter, and more particularly those caused by root intrusion, in this respect, is very important variables that characterize modulated to ensure the viability and efficiency of the irrigation system. It aims to study the differences in development and productivity with different substrate types and different types of irrigation system, one being the RLSub, handled with different treatments of the herbicide Trifluralina (TFN). Crop response by type of irrigation system used, in terms of efficiency in water use and response to the application of TFN on these and on the occurrence of root intrusion of different types of emitters, is evaluated.Este trabajo ha sido financiado a través del proyecto de investigación “Desarrollo técnico y agronómico del riego localizado subterráneo como alternativa para aumentar la eficiencia hídrica en diferentes sistemas agrícolas. 480/02PA” firmado entre la Universidad Politécnica de Cartagena (Grupo de Investigación “Agroquímica, Tecnología y manejo de Suelos y Sustratos” del Departamento Ciencia y Tecnología Agraria) y la empresa Sistema Azud S. A
Spatial dynamics of bovine tuberculosis in the Autonomous Community of Madrid, Spain (2010-2012)
Progress in control of bovine tuberculosis (bTB) is often not uniform, usually due to the effect of one or more sometimes unknown epidemiological factors impairing the success of eradication programs. Use of spatial analysis can help to identify clusters of persistence of disease, leading to the identification of these factors thus allowing the implementation of targeted control measures, and may provide some insights of disease transmission, particularly when combined with molecular typing techniques. Here, the spatial dynamics of bTB in a high prevalence region of Spain were assessed during a three year period (2010-2012) using data from the eradication campaigns to detect clusters of positive bTB herds and of those infected with certain Mycobacterium bovis strains (characterized using spoligotyping and VNTR typing). In addition, the within-herd transmission coefficient (β) was estimated in infected herds and its spatial distribution and association with other potential outbreak and herd variables was evaluated. Significant clustering of positive herds was identified in the three years of the study in the same location ("high risk area"). Three spoligotypes (SB0339, SB0121 and SB1142) accounted for >70% of the outbreaks detected in the three years. VNTR subtyping revealed the presence of few but highly prevalent strains within the high risk area, suggesting maintained transmission in the area. The spatial autocorrelation found in the distribution of the estimated within-herd transmission coefficients in herds located within distances <14 km and the results of the spatial regression analysis, support the hypothesis of shared local factors affecting disease transmission in farms located at a close proximity
Assessment of genetic diversity of zoonotic Brucella spp. recovered from livestock in Egypt using multiple locus VNTR analysis
Brucellosis is endemic in most parts of Egypt, where it is caused mainly by Brucella melitensis biovar 3, and affects cattle and small ruminants in spite of ongoing efforts devoted to its control. Knowledge of the predominant Brucella species/strains circulating in a region is a prerequisite of a brucellosis control strategy. For this reason a study aiming at the evaluation of the phenotypic and genetic heterogeneity of a panel of 17 Brucella spp. isolates recovered from domestic ruminants (cattle, buffalo, sheep, and goat) from four governorates during a period of five years (2002-2007) was carried out using microbiological tests and molecular biology techniques (PCR, MLVA-15, and sequencing). Thirteen strains were identified as B. melitensis biovar 3 while all phenotypic and genetic techniques classified the remaining isolates as B. abortus (n = 2) and B. suis biovar 1 (n = 2). MLVA-15 yielded a high discriminatory power (h = 0.801), indicating a high genetic diversity among the B. melitensis strains circulating among domestic ruminants in Egypt. This is the first report of the isolation of B. suis from cattle in Egypt which, coupled with the finding of B. abortus, suggests a potential role of livestock as reservoirs of several zoonotic Brucella species in the region
Observation of Single Top Quark Production in Association with a Z Boson in Proton-Proton Collisions at √s=13 TeV
The observation of single top quark production in association with a Z boson and a quark (tZq) is reported. Events from proton-proton collisions at a center-of-mass energy of 13 TeV containing three charged leptons (either electrons or muons) and at least two jets are analyzed. The data were collected with the CMS detector in 2016 and 2017 and correspond to an integrated luminosity of 77.4fb−1. The increased integrated luminosity, a multivariate lepton identification, and a redesigned analysis strategy improve significantly the sensitivity of the analysis compared to previous searches for tZq production. The tZq signal is observed with a significance well over 5 standard deviations. The measured tZq production cross section is σ(pp→tZq→tℓ+ℓ−q)=111±13(stat)+11−9(syst) fb, for dilepton invariant masses above 30 GeV, in agreement with the standard model expectation
Measurement of associated production of a W boson and a charm quark in proton–proton collisions at √s=13TeV
Measurements are presented of associated production of a W boson and a charm quark (W+c) in proton–proton collisions at a center-of-mass energy of 13TeV. The data correspond to an integrated luminosity of 35.7fb−1 collected by the CMS experiment at the CERN LHC. The W bosons are identified by their decay into a muon and a neutrino. The charm quarks are tagged via the full reconstruction of D∗(2010)± mesons that decay via D∗(2010)±→D0+π±→K∓+π±+π±D∗. A cross section is measured in the fiducial region defined by the muon transverse momentum pμT>26GeV, muon pseudorapidity |ημ|5GeV. The inclusive cross section for this kinematic range is σ(W+c)=1026±31(stat)+76−72(syst) pb. The cross section is also measured differentially as a function of the pseudorapidity of the muon from the WW boson decay. These measurements are compared with theoretical predictions and are used to probe the strange quark content of the proton
Measurement of the top quark mass with lepton+jets final states using p p collisions at ?s=13TeV
The mass of the top quark is measured using a sample of t t ¯ events collected by the CMS detector using proton-proton collisions at s=13TeV at the CERN LHC. Events are selected with one isolated muon or electron and at least four jets from data corresponding to an integrated luminosity of 35.9fb-1. For each event the mass is reconstructed from a kinematic fit of the decay products to a t t ¯ hypothesis. Using the ideogram method, the top quark mass is determined simultaneously with an overall jet energy scale factor (JSF), constrained by the mass of the W boson in q q ¯ ? decays. The measurement is calibrated on samples simulated at next-to-leading order matched to a leading-order parton shower. The top quark mass is found to be 172.25±0.08(stat+JSF)±0.62(syst)GeV. The dependence of this result on the kinematic properties of the event is studied and compared to predictions of different models of t t ¯ production, and no indications of a bias in the measurements are observed
Measurement of the differential Drell-Yan cross section in proton-proton collisions at √s = 13 TeV
Measurements of the differential cross section for the Drell-Yan process, based on proton-proton collision data at a centre-of-mass energy of 13 TeV, collected by the CMS experiment, are presented. The data correspond to an integrated luminosity of 2.8 (2.3) fb−1 in the dimuon (dielectron) channel. The total and fiducial cross section measurements are presented as a function of dilepton invariant mass in the range 15 to 3000 GeV, and compared with the perturbative predictions of the standard model. The measured differential cross sections are in good agreement with the theoretical calculations
Search for a low-mass τ−τ+ resonance in association with a bottom quark in proton-proton collisions at √s = 13 TeV
A general search is presented for a low-mass τ−τ+ resonance produced in association with a bottom quark. The search is based on proton-proton collision data at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb−1. The data are consistent with the standard model expectation. Upper limits at 95% confidence level on the cross section times branching fraction are determined for two signal models: a light pseudoscalar Higgs boson decaying to a pair of τ leptons produced in association with bottom quarks, and a low-mass boson X decaying to a τ-lepton pair that is produced in the decay of a bottom-like quark B such that B → bX. Masses between 25 and 70 GeV are probed for the light pseudoscalar boson with upper limits ranging from 250 to 44 pb. Upper limits from 20 to 0.3 pb are set on B masses between 170 and 450 GeV for X boson masses between 20 and 70 GeV
Measurement of exclusive Υ photoproduction from protons in pPb collisions at √sNN=5.02TeV
The exclusive photoproduction of Υ(nS) meson states from protons, γp→Υ(nS)p (with n=1,2,3), is studied in ultraperipheral pp Pb collisions at a centre-of-mass energy per nucleon pair of √sNN=5.02TeV . The measurement is performed using the Υ(nS)→μ+μ− decay mode, with data collected by the CMS experiment corresponding to an integrated luminosity of 32.6nb−1. Differential cross sections as functions of the Υ(nS) transverse momentum squared p2T, and rapidity y, are presented. The Υ(1S) photoproduction cross section is extracted in the rapidity range |y|<2.2, which corresponds to photon–proton centre-of-mass energies in the range 91<Wγp<826GeV. The data are compared to theoretical predictions based on perturbative quantum chromodynamics and to previous measurements
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