95 research outputs found
Characterization of Lasiodiplodia species associated with grapevines in Mexico
Botryosphaeria dieback is one of the most prevalent grapevine trunk diseases (GTDs), and is caused by fungi in the Botryosphaeriaceae. Fungi invade grapevine vascular systems mainly through pruning wounds, and cause cankers and necrotic
lesions, which lead to grapevine decline and death. Lasiodiplodia theobromae has been reported as a highly virulent pathogen of grapevine, and was previously reported in Mexican vineyards. The taxonomy of Lasiodiplodia was recently revised, adding new species, and some were reduced to synonymy. This study aimed to characterize Lasiodiplodia producing grapevine dieback symptoms in Sonora and Baja California, Mexico.
Using the phylogenetic markers tef1-α and ITS regions, Lasiodiplodia brasiliensis, L. crassispora, L. exigua, and L. gilanensis were identified. Lasidiplodia exigua was the most prevalent species. Lasiodiplodia brasiliensis and L. gilanensis were very virulent to
‘Cabernet Sauvignon’ plants, while L. exigua and L. gilanensis were less virulent, and L. crassispora did not produce lesions at 2 months post-inoculation. The optimum temperature of the Lasiodiplodia spp. was 28°C, but all four species grew up to 37°C, and
the isolates of L. exigua grew slowly at 40°C. This is the first report of the four of Lasiodiplodia species in vineyards of Mexico.EEA MendozaFil: Rangel Montoya, Edelweiss A. Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE). Departamento de Microbiología; MéxicoFil: Paolinelli, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paolinelli, Marcos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Rolshausen, Philippe E. University of California, Riverside. Department of Botany and Plant Sciences; Estados UnidosFil: Valenzuela Solano, Cesar. Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP). Campo Experimental Costa de Ensenada; MéxicoFil.: Hernandez Martinez, Rufina. Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE). Departamento de Microbiología; Méxic
Final results of the EDELWEISS-II WIMP search using a 4-kg array of cryogenic germanium detectors with interleaved electrodes
The EDELWEISS-II collaboration has completed a direct search for WIMP dark
matter with an array of ten 400-g cryogenic germanium detectors in operation at
the Laboratoire Souterrain de Modane. The combined use of thermal phonon
sensors and charge collection electrodes with an interleaved geometry enables
the efficient rejection of gamma-induced radioactivity as well as near-surface
interactions. A total effective exposure of 384 kg.d has been achieved, mostly
coming from fourteen months of continuous operation. Five nuclear recoil
candidates are observed above 20 keV, while the estimated background is 3.0
events. The result is interpreted in terms of limits on the cross-section of
spin-independent interactions of WIMPs and nucleons. A cross-section of
4.4x10^-8 pb is excluded at 90%CL for a WIMP mass of 85 GeV. New constraints
are also set on models where the WIMP-nucleon scattering is inelastic.Comment: 23 pages, 5 figures; matches published versio
A search for low-mass WIMPs with EDELWEISS-II heat-and-ionization detectors
We report on a search for low-energy (E < 20 keV) WIMP-induced nuclear
recoils using data collected in 2009 - 2010 by EDELWEISS from four germanium
detectors equipped with thermal sensors and an electrode design (ID) which
allows to efficiently reject several sources of background. The data indicate
no evidence for an exponential distribution of low-energy nuclear recoils that
could be attributed to WIMP elastic scattering after an exposure of 113 kg.d.
For WIMPs of mass 10 GeV, the observation of one event in the WIMP search
region results in a 90% CL limit of 1.0x10^-5 pb on the spin-independent
WIMP-nucleon scattering cross-section, which constrains the parameter space
associated with the findings reported by the CoGeNT, DAMA and CRESST
experiments.Comment: PRD rapid communication accepte
Performance of the EDELWEISS-III experiment for direct dark matter searches
We present the results of measurements demonstrating the efficiency of the EDELWEISS-III array of cryogenic germanium detectors for direct dark matter searches. The experimental setup and the FID (Fully Inter-Digitized) detector array is described, as well as the efficiency of the double measurement of heat and ionization signals in background rejection. For the whole set of 24 FID detectors used for coincidence studies, the baseline resolutions for the fiducial ionization energy are mainly below 0.7 keV (FHWM) whereas the baseline resolutions for heat energies are mainly below 1.5 keV (FWHM). The response to nuclear recoils as well as the very good discrimination capability of the FID design has been measured with an AmBe source. The surface - and -decay rejection power of per at 90% C.L. has been determined with a Pb source, the rejection of bulk -ray events has been demonstrated using -calibrations with Ba sources leading to a value of at 90% C.L.. The current levels of natural radioactivity measured in the detector array are shown as the rate of single background. The fiducial volume fraction of the FID detectors has been measured to a weighted average value of using the cosmogenic activation of the Zn and Ge isotopes. The stability and uniformity of the detector response is also discussed. The achieved resolutions, thresholds and background levels of the upgraded EDELWEISS-III detectors in their setup are thus well suited to the direct search of WIMP dark matter over a large mass range
Background studies for the EDELWEISS dark matter experiment
The EDELWEISS-II collaboration has completed a direct search for WIMP dark
matter using cryogenic Ge detectors (400 g each) and 384 kgdays of
effective exposure. A cross-section of pb is excluded at
90% C.L. for a WIMP mass of 85 GeV. The next phase, EDELWEISS-III, aims to
probe spin-independent WIMP-nucleon cross-sections down to a few
pb. We present here the study of gamma and neutron background
coming from radioactive decays in the set-up and shielding materials. We have
carried out Monte Carlo simulations for the completed EDELWEISS-II setup with
GEANT4 and normalised the expected background rates to the measured
radioactivity levels (or their upper limits) of all materials and components.
The expected gamma-ray event rate in EDELWEISS-II at 20-200 keV agrees with the
observed rate of 82 events/kg/day within the uncertainties in the measured
concentrations. The calculated neutron rate from radioactivity of 1.0-3.1
events (90% C.L.) at 20-200 keV in the EDELWEISS-II data together with the
expected upper limit on the misidentified gamma-ray events (), surface
betas (), and muon-induced neutrons (), do not contradict 5
observed events in nuclear recoil band. We have then extended the simulation
framework to the EDELWEISS-III configuration with 800 g crystals, better
material purity and additional neutron shielding inside the cryostat. The
gamma-ray and neutron backgrounds in 24 kg fiducial mass of EDELWEISS-III have
been calculated as 14-44 events/kg/day and 0.7-1.4 events per year,
respectively. The results of the background studies performed in the present
work have helped to select better purity components and improve shielding in
EDELWEISS-III to further reduce the expected rate of background events in the
next phase of the experiment.Comment: 15 pages, 9 figures, to be published in Astroparticle Physic
Muon-induced background in the EDELWEISS dark matter search
A dedicated analysis of the muon-induced background in the EDELWEISS dark
matter search has been performed on a data set acquired in 2009 and 2010. The
total muon flux underground in the Laboratoire Souterrain de Modane (LSM) was
measured to be \,muons/m/d. The
modular design of the muon-veto system allows the reconstruction of the muon
trajectory and hence the determination of the angular dependent muon flux in
LSM. The results are in good agreement with both MC simulations and earlier
measurements. Synchronization of the muon-veto system with the phonon and
ionization signals of the Ge detector array allowed identification of
muon-induced events. Rates for all muon-induced events and of WIMP-like events were extracted. After
vetoing, the remaining rate of accepted muon-induced neutrons in the
EDELWEISS-II dark matter search was determined to be at 90%\,C.L. Based on
these results, the muon-induced background expectation for an anticipated
exposure of 3000\,\kgd\ for EDELWEISS-3 is
events.Comment: 21 pages, 16 figures, Accepted for publication in Astropart. Phy
Axion searches with the EDELWEISS-II experiment
We present new constraints on the couplings of axions and more generic
axion-like particles using data from the EDELWEISS-II experiment. The EDELWEISS
experiment, located at the Underground Laboratory of Modane, primarily aims at
the direct detection of WIMPs using germanium bolometers. It is also sensitive
to the low-energy electron recoils that would be induced by solar or dark
matter axions. Using a total exposure of up to 448 kg.d, we searched for
axion-induced electron recoils down to 2.5 keV within four scenarios involving
different hypotheses on the origin and couplings of axions. We set a 95% CL
limit on the coupling to photons GeV in
a mass range not fully covered by axion helioscopes. We also constrain the
coupling to electrons, , similar to the more
indirect solar neutrino bound. Finally we place a limit on , where is the
effective axion-nucleon coupling for Fe. Combining these results we
fully exclude the mass range keV for DFSZ axions and
keV for KSVZ axions
Indução de aderência intrabdominal por prótese de retícula de polipropileno:: estudo experimental em ratos
INTRODUCTION: The correction of groin hernias using a transperitoneal videolaparoscopic method with a polypropylene mesh is becoming increasingly common. This could lead to an increased incidence of adhesion formation.MATERIALS AND METHODS: The incidence of adhesions induced by mesh placement and by reperitonization was observed in 40 male adult Wistar rats, randomlyallocated to four groups of 10 rats (Group A = no mesh, no reperitonization; B = no mesh, reperitonization; C = mesh, no reperitonization; D = mesh and reperitonization). After opening the abdominal cavity, the iliac fossa was identified and a peritoneal opening, measuring about 2 by 2 cm, was done on the parietal wall. In the rats in which a polypropylene prosthesis was used, a piece of Marlex mesh, measuring about 1.5 by 1.5 cm was placed on the peritoneal opening. A simple suture was performed in the animals submitted to reperitonization, using a 5.0 monofilamentar polypropylene thread on a cardiovascular (atraumatic) needle. The animals were killed 15 days after the operation. Macroscopic analysis was done by an investigator blinded to intervention group. Fisher’s exact test and the c2 test were used for statistical analysis of the results. A P < 0.05 was considered as significant.RESULTS: Adhesions were significantly more common in the groups in which the prosthesis was placed (59% vs. 95%; P = 0.01), as well as in the groups in whichreperitonization was performed (58% vs. 100%; P = 0.03).CONCLUSIONS: The results suggest that polypropylene mesh placement and reperitonization are each independent factors that have a role in inducing the formationof adhesions.INTRODUÇÃO: A correção de hérnias na virilha através de um método videolaparoscópico transperitoneal está se tornando cada vez mais comum. Contudo,este método poderia levar a um aumento na incidência de formação de aderências.MATERIAIS E MÉTODOS: A incidência de aderências induzidas pela colocação de retícula e pela reperitonização foram observadas em 40 ratos Wistar adultos, machos, divididos aleatoriamente em quatro grupos com 10 ratos cada um (Grupo A = sem retícula, sem reperitonização; B = sem retícula, com reperitonização; C = com retícula, sem reperitonização; D = retícula e reperitonização). Após a abertura da cavidade abdominal, a fossa ilíaca foi identificada e fez-se uma abertura de aproximadamente 2 x 2 cm na parede parietal. Nos ratos em que uma prótese de polipropileno foi utilizada, uma retícula Marlex com 1,5 x 1,5 cm foi colocada sobre a abertura peritoneal. Nos outros animais, a reperitonização foi feita com sutura simples, utilizando-se fio de polipropileno monofilamentar 5.0 com uma agulha cardiovascular (atraumática). Os animais foram sacrificados 15 dias depois da operação. A análise macroscópica foi realizada por um investigador cego quanto ao grupo de origem dos animais. A análise estatística utilizou o teste exato de Fisher e o c2. Um P < 0,05 foi considerado significativo.RESULTADOS: As aderências foram significativamente mais comuns nos grupos nos quais a prótese foi utilizada (59% vs. 95%; P = 0,01), assim como nos gruposnos quais foi feita a reperitonização (58% vs. 100%; P = 0,03). CONCLUSÕES: Os resultados sugerem que a retícula de polipropileno e a reperitonização são fatores independentes entre si quanto à indução de formaçãode aderências
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