5,122 research outputs found
Ultrastructural Study of Yam Tuber as Related to Postharvest Hardness
Usually, parenchyma cell walls of monocotyledons do not develop secondary walls; however a few days after harvesting, the yam tuber of Dioscorea dumetorum starts to harden. Two or three weeks Iater, hardness is so pronounced that the tubers cannot be eaten, even after a long cooking time.
Cytochemical studies using autofluorescence or some fluorescent dyes, such as phloroglucinol hydrochloride showed that the thin, and flexible cell walls of parenchyma tubers very quickly became fully lignified after harvesting. Ultrastructura 1 stud ies of the hardened ce 11 wa 11 s showed very thick secondary wa 11 s and very deep pit apertures. These secondary walls reacted strong ly with li gn in reactants such as potassium permanganate. The use of a radioactive (l \u27• C) ce llulose precursor, uri dine- 5\u27-d ipho sphateglucose, confirmed the formation of such secondary walls. The lignification started from the corners of the cells around intercellular spaces and proceeded along the walls
Etude spectrale de l'échantillonnage par traversée de niveaux
La tendance actuelle en microélectronique est d'intégrer des systèmes complexes sur une seule puce (« SoC » pour Sytems on chip): capteur, convertisseur analogique-numérique (CAN), traitement numérique du signal, transmission de données. Ces systèmes doivent être peu coûteux, de taille réduite, faible bruit et surtout peu consommateur d'énergie parce qu'il sont souvent alimentés par batteries. Parmi les étages cités, les CAN sont les plus difficiles à concevoir dans le respect du cahier des charges. Dans cette perspective, une nouvelle classe de convertisseur a été développée à partir de l'association de la technologie asynchrone et de l'échantillonnage non uniforme par traversée de niveaux. Le schéma d'échantillonnage est analysé pour les signaux périodiques mettant en évidence un repliement de spectre. Cependant l'étude de la reconstruction montre qu'un signal peut être reconstruit grâce à l'information portée par les intervalles de temps et ce malgré le repliement
Fatty acid profile in peri-prostatic adipose tissue and prostate cancer aggressiveness in African-Caribbean and Caucasian patients
BACKGROUND: Genetic and nutritional factors have been linked to the risk of aggressive prostate cancer (PCa). The fatty acid (FA) composition of peri-prostatic adipose tissue (PPAT), which reflects the past FA intake, is potentially involved in PCa progression. We analysed the FA composition of PPAT, in correlation with the ethno-geographical origin of the patients and markers of tumour aggressiveness.
METHODS: From a cohort of 1000 men treated for PCa by radical prostatectomy, FA composition of PPAT was analysed in 156 patients (106 Caucasians and 50 African-Caribbeans), 78 with an indolent tumour (ISUP group 1 + pT2 + PSA <10 ng/mL) and 78 with an aggressive tumour (ISUP group 4-5 + pT3). The effect of FA extracted from PPAT on in-vitro migration of PCa cells DU145 was studied in 72 patients, 36 Caucasians, and 36 African-Caribbeans.
RESULTS: FA composition differed according to the ethno-geographical origin. Linoleic acid, an essential n-6 FA, was 2-fold higher in African-Caribbeans compared with Caucasian patients, regardless of disease aggressiveness. In African-Caribbeans, the FA profile associated with PCa aggressiveness was characterised by low level of linoleic acid along with high levels of saturates. In Caucasians, a weak and negative association was observed between eicosapentaenoic acid level (an n-3 FA) and disease aggressiveness. In-vitro migration of PCa cells using PPAT from African-Caribbean patients was associated with lower content of linoleic acid.
CONCLUSION: These results highlight an important ethno-geographical variation of PPAT, in both their FA content and association with tumour aggressiveness
Measurement of the mass and lifetime of the baryon
A proton-proton collision data sample, corresponding to an integrated
luminosity of 3 fb collected by LHCb at and 8 TeV, is used
to reconstruct , decays. Using the , decay mode for calibration, the lifetime ratio and absolute
lifetime of the baryon are measured to be \begin{align*}
\frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\
\tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the
uncertainties are statistical, systematic and from the calibration mode (for
only). A measurement is also made of the mass difference,
, and the corresponding mass, which
yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm
MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2.
\end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm
Measurements of differential cross sections of Z/gamma*+jets+X events in proton anti-proton collisions at sqrt{s}=1.96 TeV
We present cross section measurements for Z/gamma*+jets+X production,
differential in the transverse momenta of the three leading jets. The data
sample was collected with the D0 detector at the Fermilab Tevatron proton
anti-proton collider at a center-of-mass energy of 1.96 TeV and corresponds to
an integrated luminosity of 1 fb-1. Leading and next-to-leading order
perturbative QCD predictions are compared with the measurements, and agreement
is found within the theoretical and experimental uncertainties. We also make
comparisons with the predictions of four event generators. Two
parton-shower-based generators show significant shape and normalization
differences with respect to the data. In contrast, two generators combining
tree-level matrix elements with a parton shower give a reasonable description
of the the shapes observed in data, but the predicted normalizations show
significant differences with respect to the data, reflecting large scale
uncertainties. For specific choices of scales, the normalizations for either
generator can be made to agree with the measurements.Comment: Published in PLB. 11 pages, 3 figure
Search for R-parity Violating Supersymmetry in Dimuon and Four-Jets Channel
We present results of a search for R-parity-violating decay of the neutralino
chi_1^0, taken to be the Lightest Supersymmetric Particle. It is assumed that
this decay proceeds through one of the lepton-number violating couplings
lambda-prime_2jk (j=1,2; k=1,2,3). This search is based on 77.5 pb-1 of data,
collected by the D0 experiment at the Fermilab Tevatron in ppbar collisions at
a center of mass energy of 1.8 TeV in 1992-1995.Comment: 10 pages, 3 figure
Simultaneous measurement of the ratio B(t->Wb)/B(t->Wq) and the top quark pair production cross section with the D0 detector at sqrt(s)=1.96 TeV
We present the first simultaneous measurement of the ratio of branching
fractions, R=B(t->Wb)/B(t->Wq), with q being a d, s, or b quark, and the top
quark pair production cross section sigma_ttbar in the lepton plus jets channel
using 0.9 fb-1 of ppbar collision data at sqrt(s)=1.96 TeV collected with the
D0 detector. We extract R and sigma_ttbar by analyzing samples of events with
0, 1 and >= 2 identified b jets. We measure R = 0.97 +0.09-0.08 (stat+syst) and
sigma_ttbar = 8.18 +0.90-0.84 (stat+syst)} +/-0.50 (lumi) pb, in agreement with
the standard model prediction.Comment: submitted to Phys.Rev.Letter
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
Search for charged Higgs bosons decaying to top and bottom quarks in ppbar collisions
We describe a search for production of a charged Higgs boson, q \bar{q'} ->
H^+, reconstructed in the t\bar{b} final state in the mass range 180 <= M_{H^+}
<= 300 GeV. The search was undertaken at the Fermilab Tevatron collider with a
center-of-mass energy sqrt{s} = 1.96 TeV and uses 0.9 fb^{-1} of data collected
with the D0 detector. We find no evidence for charged Higgs boson production
and set upper limits on the production cross section in the Types I, II and III
two-Higgs-doublet models (2HDMs). An excluded region in the (M_{H^+},tan\beta)
plane for Type I 2HDM is presented.Comment: Submitted to Phys. Rev. Letter
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