1,085 research outputs found
Critical generalized inverse participation ratio distributions
The system size dependence of the fluctuations in generalized inverse
participation ratios (IPR's) at criticality is investigated
numerically. The variances of the IPR logarithms are found to be
scale-invariant at the macroscopic limit. The finite size corrections to the
variances decay algebraically with nontrivial exponents, which depend on the
Hamiltonian symmetry and the dimensionality. The large- dependence of the
asymptotic values of the variances behaves as according to theoretical
estimates. These results ensure the self-averaging of the corresponding
generalized dimensions.Comment: RevTex4, 5 pages, 4 .eps figures, to be published in Phys. Rev.
Holocene depositional history inferred from single-grain luminescence ages in southern California, North America.
Significant sediment flux and deposition in a sedimentary system are influenced by climate changes, tectonics, lithology, and the sedimentary system’s internal dynamics. Identifying the timing of depositional periods from stratigraphic records is a first step to critically evaluating the controls of sediment flux and deposition. Here, we show that ages of single-grain K-feldspar luminescence subpopulations may provide information on the timing of previous major depositional periods. We analyzed 754 K-feldspar single-grains from 17 samples from the surface to ~9 m-depth in a trench located downstream of the Mission Creek catchment. Single-grain luminescence subpopulation ages significantly overlap at least eight times since ~12.0 ka indicating a common depositional history. These depositional periods correspond reasonably well with the wetter climate periods based on hydroclimatic proxies from nearby locations. Our findings imply a first-order climatic control on sediment depositional history in southern California on a millennial timescale
Anomalously localized states and multifractal correlations of critical wavefunctions in two-dimensional electron systems with spin-orbital interactions
Anomalously localized states (ALS) at the critical point of the Anderson
transition are studied for the SU(2) model belonging to the two-dimensional
symplectic class. Giving a quantitative definition of ALS to clarify
statistical properties of them, the system-size dependence of a probability to
find ALS at criticality is presented. It is found that the probability
increases with the system size and ALS exist with a finite probability even in
an infinite critical system, though the typical critical states are kept to be
multifractal. This fact implies that ALS should be eliminated from an ensemble
of critical states when studying critical properties from distributions of
critical quantities. As a demonstration of the effect of ALS to critical
properties, we show that the distribution function of the correlation dimension
of critical wavefunctions becomes a delta function in the thermodynamic limit
only if ALS are eliminated.Comment: 7 pages, 6 figure
Roadmap Consensus on Carotid Artery Plaque Imaging and Impact on Therapy Strategies and Guidelines: An International, Multispecialty, Expert Review and Position Statement
Current guidelines for primary and secondary prevention of stroke in patients with carotid atherosclerosis are based on the quantification of the degree of stenosis and symptom status. Recent publications have demonstrated that plaque morphology and composition, independent of the degree of stenosis, are important in the risk stratification of carotid atherosclerotic disease. This finding raises the question as to whether current guidelines are adequate or if they should be updated with new evidence, including imaging for plaque phenotyping, risk stratification, and clinical decision-making in addition to the degree of stenosis. To further this discussion, this roadmap consensus article defines the limits of luminal imaging and highlights the current evidence supporting the role of plaque imaging. Furthermore, we identify gaps in current knowledge and suggest steps to generate high-quality evidence, to add relevant information to guidelines currently based on the quantification of stenosis.</p
Avances en el estudio de las bases genéticas y organolépticas del cacao fino o de aroma en el Perú
Las variedades de cacao fino o de aroma en el Perú son utilizados para elaborar los mejores chocolates del
mundo por sus exquisitas y poco comunes características organolépticas, Estas características permiten que
el cacao peruano gane reconocimiento internacional y de ahí su gran valor económico. A pesar de esto,
poco se sabe sobre los componentes genéticos y/o ambientales que contribuyen a la exclusividad de este
valioso recurso económico. En el proyecto de investigación aplicada: “Estudio molecular de la diversidad
genética de los cacaos aromáticos en el Perú con fines del fortalecimiento de su competitividad y aumento
de la producción nacional de cacao de calidad”, financiado por Innóvate Perú del Ministerio de la
Producción, se tiene como objetivos determinar la variabilidad genética y caracterización organoléptica de
más de 100 tipos de cacao fino o de aroma que se cultivan a lo largo de las cinco principales regiones del
Perú (Amazonas, Cusco, San Martin, Piura y Huánuco). Adicionalmente, la Universidad Nacional Agraria
de la Selva en Tingo María y el Instituto de Investigaciones de la Amazonia Peruana en Tarapoto,
hospedarán bancos de germoplasma y de propagación de esquejes para la difusión y estudios de estos
valiosos recursos. Hasta inicios del 2017, ya se han recolectado más de 80 genotipos provenientes de las
cinco regiones. Protocolos para análisis sensoriales que cumplan los más rigurosos estándares
internacionales se han venido estableciendo. Por otro lado, técnicas de marcadores moleculares usando
marcadores de DNA tipo SSR y SNPs, seguido por secuenciamiento de ADN, se vienen estableciendo.
Estudios de asociación de fenotipo-genotipo formarán parte del conocimiento generado en este proyecto.
Adicionalmente, estos conocimientos permitirán generar información genómica valiosa para salvaguardar
nuestra biodiversidad nativa, otorgándole a los productores y sus asociaciones de herramientas para
proteger sus recursos genéticos y a los potenciales mejoradores de cacao más luces en cuanto a la asociación
genotipo-calidad. Se espera que a fin del proyecto, se cuente con los resultados de genotipificación de más
de 100 genotipos de cacao fino o de aroma y mediante el resecuenciamiento se revelen SNPs particulares
para cada grupo genético en cada región muestreada
Search for composite and exotic fermions at LEP 2
A search for unstable heavy fermions with the DELPHI detector at LEP is
reported. Sequential and non-canonical leptons, as well as excited leptons and
quarks, are considered. The data analysed correspond to an integrated
luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV
and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172
GeV and 161 GeV. The search for pair-produced new leptons establishes 95%
confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2,
depending on the channel. The search for singly produced excited leptons and
quarks establishes upper limits on the ratio of the coupling of the excited
fermio
Search for charginos in e+e- interactions at sqrt(s) = 189 GeV
An update of the searches for charginos and gravitinos is presented, based on
a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector
in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was
found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a
centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by
combining the chargino searches with neutralino searches at the Z resonance
implies a limit on the mass of the lightest neutralino which, for a heavy
sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure
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
Search for lightest neutralino and stau pair production in light gravitino scenarios with stau NLSP
Promptly decaying lightest neutralinos and long-lived staus are searched for
in the context of light gravitino scenarios. It is assumed that the stau is the
next to lightest supersymmetric particle (NLSP) and that the lightest
neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector
at centre-of-mass energies from 161 to 183 \GeV are analysed. No evidence of
the production of these particles is found. Hence, lower mass limits for both
kinds of particles are set at 95% C.L.. The mass of gaugino-like neutralinos is
found to be greater than 71.5 GeV/c^2. In the search for long-lived stau,
masses less than 70.0 to 77.5 \GeVcc are excluded for gravitino masses from 10
to 150 \eVcc . Combining this search with the searches for stable heavy leptons
and Minimal Supersymmetric Standard Model staus a lower limit of 68.5 \GeVcc
may be set for the stau mas
Hadronization properties of b quarks compared to light quarks in e+e- -> q qbar from 183 to 200 GeV
The DELPHI detector at LEP has collected 54 pb^{-1} of data at a
centre-of-mass energy around 183 GeV during 1997, 158 pb^{-1} around 189 GeV
during 1998, and 187 pb^{-1} between 192 and 200 GeV during 1999. These data
were used to measure the average charged particle multiplicity in e+e- -> b
bbar events, _{bb}, and the difference delta_{bl} between _{bb} and the
multiplicity, _{ll}, in generic light quark (u,d,s) events: delta_{bl}(183
GeV) = 4.55 +/- 1.31 (stat) +/- 0.73 (syst) delta_{bl}(189 GeV) = 4.43 +/- 0.85
(stat) +/- 0.61 (syst) delta_{bl}(200 GeV) = 3.39 +/- 0.89 (stat) +/- 1.01
(syst). This result is consistent with QCD predictions, while it is
inconsistent with calculations assuming that the multiplicity accompanying the
decay of a heavy quark is independent of the mass of the quark itself.Comment: 13 pages, 2 figure
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