421 research outputs found
Mapping of Mycobacterium tuberculosis Complex Genetic Diversity Profiles in Tanzania and Other African Countries
The aim of this study was to assess and characterize Mycobacterium tuberculosis complex (MTBC) genotypic diversity in Tanzania, as well as in neighbouring East and other several African countries. We used spoligotyping to identify a total of 293 M. tuberculosis clinical isolates (one isolate per patient) collected in the Bunda, Dar es Salaam, Ngorongoro and Serengeti areas in Tanzania. The results were compared with results in the SITVIT2 international database of the Pasteur Institute of Guadeloupe. Genotyping and phylogeographical analyses highlighted the predominance of the CAS, T, EAI, and LAM MTBC lineages in Tanzania. The three most frequent Spoligotype International Types (SITs) were: SIT21/CAS1-Kili (n = 76; 25.94%), SIT59/LAM11-ZWE (n = 22; 7.51%), and SIT126/EAI5 tentatively reclassified as EAI3-TZA (n = 18; 6.14%). Furthermore, three SITs were newly created in this study (SIT4056/EAI5 n = 2, SIT4057/T1 n = 1, and SIT4058/EAI5 n = 1). We noted that the East-African-Indian (EAI) lineage was more predominant in Bunda, the Manu lineage was more common among strains isolated in Ngorongoro, and the Central-Asian (CAS) lineage was more predominant in Dar es Salaam (p-value<0.0001). No statistically significant differences were noted when comparing HIV status of patients vs. major lineages (p-value = 0.103). However, when grouping lineages as Principal Genetic Groups (PGG), we noticed that PGG2/3 group (Haarlem, LAM, S, T, and X) was more associated with HIV-positive patients as compared to PGG1 group (Beijing, CAS, EAI, and Manu) (p-value = 0.03). This study provided mapping of MTBC genetic diversity in Tanzania (containing information on isolates from different cities) and neighbouring East African and other several African countries highlighting differences as regards to MTBC genotypic distribution between Tanzania and other African countries. This work also allowed underlining of spoligotyping patterns tentatively grouped within the newly designated EAI3-TZA lineage (remarkable by absence of spacers 2 and 3, and represented by SIT126) which seems to be specific to Tanzania. However, further genotyping information would be needed to confirm this specificity
Charge separation relative to the reaction plane in Pb-Pb collisions at TeV
Measurements of charge dependent azimuthal correlations with the ALICE
detector at the LHC are reported for Pb-Pb collisions at TeV. Two- and three-particle charge-dependent azimuthal correlations in
the pseudo-rapidity range are presented as a function of the
collision centrality, particle separation in pseudo-rapidity, and transverse
momentum. A clear signal compatible with a charge-dependent separation relative
to the reaction plane is observed, which shows little or no collision energy
dependence when compared to measurements at RHIC energies. This provides a new
insight for understanding the nature of the charge dependent azimuthal
correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at , 2.76 and 7 TeV
Measurements of the sphericity of primary charged particles in minimum bias
proton--proton collisions at , 2.76 and 7 TeV with the ALICE
detector at the LHC are presented. The observable is linearized to be collinear
safe and is measured in the plane perpendicular to the beam direction using
primary charged tracks with GeV/c in . The
mean sphericity as a function of the charged particle multiplicity at
mid-rapidity () is reported for events with different
scales ("soft" and "hard") defined by the transverse momentum of the leading
particle. In addition, the mean charged particle transverse momentum versus
multiplicity is presented for the different event classes, and the sphericity
distributions in bins of multiplicity are presented. The data are compared with
calculations of standard Monte Carlo event generators. The transverse
sphericity is found to grow with multiplicity at all collision energies, with a
steeper rise at low , whereas the event generators show the
opposite tendency. The combined study of the sphericity and the mean with multiplicity indicates that most of the tested event generators
produce events with higher multiplicity by generating more back-to-back jets
resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with
tune PERUGIA-2011 exhibits a noticeable improvement in describing the data,
compared to the other tested generators.Comment: 21 pages, 9 captioned figures, 3 tables, authors from page 16,
published version, figures from
http://aliceinfo.cern.ch/ArtSubmission/node/308
Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at TeV
The inclusive transverse momentum () distributions of primary
charged particles are measured in the pseudo-rapidity range as a
function of event centrality in Pb-Pb collisions at
TeV with ALICE at the LHC. The data are presented in the range
GeV/ for nine centrality intervals from 70-80% to 0-5%.
The Pb-Pb spectra are presented in terms of the nuclear modification factor
using a pp reference spectrum measured at the same collision
energy. We observe that the suppression of high- particles strongly
depends on event centrality. In central collisions (0-5%) the yield is most
suppressed with at -7 GeV/. Above
GeV/, there is a significant rise in the nuclear modification
factor, which reaches for GeV/. In
peripheral collisions (70-80%), the suppression is weaker with almost independently of . The measured nuclear
modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/284
Particle-yield modification in jet-like azimuthal di-hadron correlations in Pb-Pb collisions at = 2.76 TeV
The yield of charged particles associated with high- trigger
particles ( GeV/) is measured with the ALICE detector in
Pb-Pb collisions at = 2.76 TeV relative to proton-proton
collisions at the same energy. The conditional per-trigger yields are extracted
from the narrow jet-like correlation peaks in azimuthal di-hadron correlations.
In the 5% most central collisions, we observe that the yield of associated
charged particles with transverse momenta GeV/ on the
away-side drops to about 60% of that observed in pp collisions, while on the
near-side a moderate enhancement of 20-30% is found.Comment: 15 pages, 2 captioned figures, 1 table, authors from page 10,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/350
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
Optimization of Pathogenicity Tests for Selection of Native Isolates of Entomopathogenic Fungi Isolated from Citrusgrowing Areas of México on Adults ofDiaphorina citriKuwayama (Hemiptera: Liviidae)
Huanglonbing (HLB), es considerado una de las más letales enfermedades de los cítricos alrededor del mundo, y ha alcanzado las principales áreas de producción de limón Mexicano (Citrus latifolia Tanaka) en la costa del pacifico de México. Los productores han iniciado el uso de insecticidas para controlar las poblaciones del psílido asiático de los cítricos, Diaphorina citri Kuwayama (Hemiptera: Liviidae), el vector del patógeno ‘Candidatus Liberibacter asiaticus’ asociado con el HLB. Actualmente los costos de los insecticidas y los efectos secundarios de su uso son las principales preocupaciones, ya que podrían perjudicar la estrategia de manejo contra el vector; y por lo tanto, alternativas ecológicas y económicamente viables a los insecticidas convencionales serian necesarias a corto plazo. Por tanto, el objetivo de este estudio fue evaluar la patogenicidad de 27 aislados nativos y 3 cepas de hongos entomopatógenos para determinar su potencial como agentes de control biológico sobre Diaphorina citri usando 2 diferentes métodos de bioensayo. Los bioensayos fueron realizados bajo condiciones de laboratorio (26 ± 2 °C, 60 ± 5% H.R y 16:8 h L:O) mediante la exposición de insectos adultos a una concentración de 1 × 108 conidios por mililitro utilizando 2 diferentes métodos de aplicación, es decir, por asperjado de esporas en las plántulas de cítricos y por asperjado directo a los psílidos adultos. Los resultados mostraron que para el asperjado directo a los adultos los aislados HIB-24 (B. bassiana) y HIB-32 (I. fumosorosea) mostraron el mayor porcentaje de mortalidad (60.66%). Respecto al asperjado de plántulas el aislado HIB-19 (I. fumosorosea) mostró el mayor porcentaje de mortalidad (62.02%). Los resultados de este estudio demuestran el potencial para el uso de hongos entomopatógenos en el manejo de D. citri en México.
ABSTRACT
Huanglongbing (HLB), considered one of the most lethal diseases of citrus worldwide, has reached the main areas of Mexican lime (Citrus latifolia Tanaka) fruit production on the Pacific coast of México. Growers have initiated intensive use of insecticides in order to control populations of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), the vector of the pathogen, ‘Candidatus Liberibacter asiaticus’ associated with huanglongbing. Presently, costs of insecticides and the side effects of their use are major concerns, because they could impair the management strategy against the vector; and thus, ecologically and economically viable alternatives to conventional insecticides are required in the short term. Therefore the goal of this study was to evaluate the pathogenicity of 27 native isolates and 3 strains of entomopathogenic fungi and determine their potential as biological control agents of D. citri by using 2 different bioassay methods. Bioassays were performed under laboratory conditions (26 ± 2 °C, 60 ± 5% RH and 16:8 h L:D) by exposing adult insects to a concentration of 1 × 108 conidia per milliliter using 2 different application methods, i.e., spraying the spores onto the citrus seedlings and spraying the spores directly onto the adult psyllids. The results showed that by direct spraying the adults, HIB-24 (B. bassiana) and HIB-32 (I. fumosorosea) isolates showed the highest mortality (60.66%). Regarding spraying of the seedlings, HIB-19 (I. fumosorosea) showed the highest percentage of mortality (62.02%). The results from this study demonstrate potential for using entomopathogenic fungi in the management of D. citri in México
Measurement of charm production at central rapidity in proton-proton collisions at TeV
The -differential production cross sections of the prompt (B
feed-down subtracted) charmed mesons D, D, and D in the rapidity
range , and for transverse momentum GeV/, were
measured in proton-proton collisions at TeV with the ALICE
detector at the Large Hadron Collider. The analysis exploited the hadronic
decays DK, DK, DD, and their charge conjugates, and was performed on a
nb event sample collected in 2011 with a
minimum-bias trigger. The total charm production cross section at TeV and at 7 TeV was evaluated by extrapolating to the full phase space
the -differential production cross sections at TeV
and our previous measurements at TeV. The results were compared
to existing measurements and to perturbative-QCD calculations. The fraction of
cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/307
Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV
We report the first measurement of charged particle elliptic flow in Pb-Pb
collisions at 2.76 TeV with the ALICE detector at the CERN Large Hadron
Collider. The measurement is performed in the central pseudorapidity region
(||<0.8) and transverse momentum range 0.2< < 5.0 GeV/. The
elliptic flow signal v, measured using the 4-particle correlation method,
averaged over transverse momentum and pseudorapidity is 0.087 0.002
(stat) 0.004 (syst) in the 40-50% centrality class. The differential
elliptic flow v reaches a maximum of 0.2 near = 3
GeV/. Compared to RHIC Au-Au collisions at 200 GeV, the elliptic flow
increases by about 30%. Some hydrodynamic model predictions which include
viscous corrections are in agreement with the observed increase.Comment: 10 pages, 4 captioned figures, published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/389
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