2,144 research outputs found
\u3cem\u3eHymenachne Amplexicaluis\u3c/em\u3e [(Rudge) Nees] Genetic Resources Collection in México, a Suitable Grass for Flood Plains in Tropical Areas
Hymenachne amplexicaluis [( Rudge ) Nees; 2n= 2x= 24; Azuche, West Indian marsh grass] is a native Central and South America C3 grass that grows well under intermittent flooding conditions. It produces good seed set and stolons to thrive on new areas assuring its survival, combined with an efficient N metabolism to promote vigorous new growing leaves and tillers (Antel et al., 1998). Azuche is a dual attribute species when introduced to new areas; it has valuable forage attributes but also is a potential weed (Hill, 2000). As Azuche is a native species, one must deal with in the best possible way within Tropical Latin America areas (Enríquez et al., 2004). No report has been found to date on living genetic resources collection and evaluation for this species
Multiphoton processes via conditional measurements in the two-field interaction
In this contribution, we show that the use of conditional measurements in the
resonant interaction of two quantized electromagnetic fields gives rise to
nonclassical multiphoton processes. Furthermore, we demonstrate that this
phenomenon may enable a robust integrated-optics protocol to engineer quantum
states containing a high number of photons, thus making it a potentially
appealing platform for exploring mesoscopic quantum phenomena.Comment: 12 pages, 6 figure
Degree of polarization and quantum-mechanical purity
The purity parameter is used in quantum mechanics to discriminate
pure states from mixed states. We employ this concept to define a
degree of polarization for general, three-dimensional, classical
random electric fields. Our approach leads to a result that is
identical with a recent definition obtained by a decomposition of
the polarization matrix in terms of the Gell-Mann matrices. We
also give an expression for this degree of polarization based on
the constituent two-dimensional subsystems
Coherent Quantum Transport in Photonic Lattices
Transferring quantum states efficiently between distant nodes of an
information processing circuit is of paramount importance for scalable quantum
computing. We report on the first observation of a perfect state transfer
protocol on a lattice, thereby demonstrating the general concept of trans-
porting arbitrary quantum information with high fidelity. Coherent transfer
over 19 sites is realized by utilizing judiciously designed optical structures
consisting of evanescently coupled waveguide ele- ments. We provide unequivocal
evidence that such an approach is applicable in the quantum regime, for both
bosons and fermions, as well as in the classical limit. Our results illustrate
the potential of the perfect state transfer protocol as a promising route
towards integrated quantum computing on a chip
Highly responsive UV-photodetectors based on single electrospun TiO2 nanofibres
In this work we study the optoelectronic properties of individual TiO2 fibres
produced through coupled sol-gel and electrospinning, by depositing them onto
pre-patterned Ti/Au electrodes on SiO2/Si substrates. Transport measurements in
the dark give a conductivity above 2*10^-5 S, which increases up to 8*10^-5 S
in vacuum. Photocurrent measurements under UV-irradiation show high sensitivity
(responsivity of 90 A/W for 375 nm wavelength) and a response time to
illumination of ~ 5 s, which is superior to state-of-the-art TiO2-based UV
photodetectors. Both responsivity and response speed are higher in air than in
vacuum, due to oxygen adsorbed on the TiO2 surface which traps photoexcited
free electrons in the conduction band, thus reducing the recombination
processes. The photodetectors are sensitive to light polarization, with an
anisotropy ratio of 12%. These results highlight the interesting combination of
large surface area and low 1D transport resistance in electrospun TiO2 fibres.
The simplicity of the sol-gel/electrospinning synthesis method, combined with a
fast response and high responsivity makes them attractive candidates for
UV-photodetection in ambient conditions. We anticipate their high (photo)
conductance is also relevant for photocatalysis and dye-sensitized solar cells.Comment: 29 pages, 5 figures in the main text, 9 figures in the Supporting
Information. in J. Mater. Chem. C, 201
Manejo Integral de Agua y Suelo en Centroamérica. Bases científicas para el desarrollo rural comunitario.
Este libro recoge los frutos de la colaboración y trabajo conjunto de un grupo de Universidades Iberoamericanas entre 2007 y 2012 el marco de las actividades del Programa de Cooperación Comunidad, Agua y Bosque en Centroamérica (CAB Centroamérica, http://www2.caminos.upm.es/Departamentos/imt/Topografia/Cab/cab.html ). Las actividades se han realizado con el apoyo del Programa de Cooperación Universitaria PCI-AECID IBEROAMÉRICA, de la Dirección de Cooperación para el Desarrollo de la Universidad Politécnica de Madrid y de los fondos propios de las Universidades latinoamericanas, con especial mención a la Universidad de Costa Rica, coordinadora de los trabajos en Centroamérica. El inicio de esta colaboración se produjo en 2007 a partir de la identificación de un objetivo común: profundizar la investigación sobre la dinámica agua-suelo-planta para mejorar la producción y la calidad del agua de los sistemas de abastecimiento comunitarios en Centroamérica
Severity-Related Changes of Bronchial Microbiome in Chronic Obstructive Pulmonary Disease
Bronchial colonization by potentially pathogenic microorganisms (PPMs) is often demonstrated in chronic obstructive pulmonary disease (COPD), but culture-based techniques identify only a portion of the bacteria in mucosal surfaces. The aim of the study was to determine changes in the bronchial microbiome of COPD associated with the severity of the disease. The bronchial microbiome of COPD patients was analyzed by 16S rRNA gene amplification and pyrosequencing in sputum samples obtained during stable disease. Seventeen COPD patients were studied (forced expiratory volume in the first second expressed as a percentage of the forced vital capacity [FEV1%] median, 35.0%; interquartile range [IQR], 31.5 to 52.0), providing a mean of 4,493 (standard deviation [SD], 2,598) sequences corresponding to 47 operational taxonomic units (OTUs) (SD, 17) at a 97% identity level. Patients were dichotomized according to their lung function as moderate to severe when their FEV1% values were over the median and as advanced when FEV1% values were lower. The most prevalent phyla in sputum were Proteobacteria (44%) and Firmicutes (16%), followed by Actinobacteria (13%). A greater microbial diversity was found in patients with moderate-to-severe disease, and alpha diversity showed a statistically significant decrease in patients with advanced disease when assessed by Shannon (ρ = 0.528; P = 0.029, Spearman correlation coefficient) and Chao1 (ρ = 0.53; P = 0.028, Spearman correlation coefficient) alpha-diversity indexes. The higher severity that characterizes advanced COPD is paralleled by a decrease in the diversity of the bronchial microbiome, with a loss of part of the resident flora that is replaced by a more restricted microbiota that includes PPMs
Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC
The uncertainty on the calorimeter energy response to jets of particles is
derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is measured and
compared to the Monte Carlo simulation using proton-proton collisions at
centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009
and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter
response to specific types of particles (positively and negatively charged
pions, protons, and anti-protons) is measured and compared to the Monte Carlo
predictions. Finally, the jet energy scale uncertainty is determined by
propagating the response uncertainty for single charged and neutral particles
to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3%
for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table,
submitted to European Physical Journal
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
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