2,673 research outputs found
Proyecto para la creación de una empresa de confección de camisetas a base de algodón orgánico en la ciudad de Guayaquil
Este documento presenta un análisis de viabilidad y factibilidad de implantar una fábrica que confeccione camisetas en la ciudad de Guayaquil y muestra el plan de negocios para esta empresa. Para esto se realizó un análisis del sector textil e investigación de mercados para identificar estrategias y acciones a seguir. La investigación incluyó a compradores en centros comerciales y competencia en el mercado. En base a la investigación sectorial y a resultados del análisis de la investigación se llegó a la conclusión que el proyecto es totalmente viable; debido a que hay una gran disposición ecologista de la gente y que estarían dispuestos a comprar, y es también factible; porque a través de la aplicación de estrategia de nicho de mercado y diferentes tácticas, la fábrica logrará participación de mercado y sobre todo alta rentabilidad.FEN-ESPO
Polariton Lasing in a Multilevel Quantum Dot Strongly Coupled To a Single Photon Mode
We present an approximate analytic expression for the photoluminescence
spectral function of a model polariton system, which describes a quantum dot,
with a finite number of fermionic levels, strongly interacting with the lowest
photon mode of a pillar microcavity. Energy eigenvalues and wavefunctions of
the electron-hole-photon system are obtained by numerically diagonalizing the
Hamiltonian. Pumping and photon losses through the cavity mirrors are described
with a master equation, which is solved in order to determine the stationary
density matrix. The photon first-order correlation function, from which the
spectral function is found, is computed with the help of the Quantum Regression
Theorem. The spectral function qualitatively describes the polariton lasing
regime in the model, corresponding to pumping rates two orders of magnitude
lower than those needed for ordinary (photon) lasing. The second-order
coherence functions for the photon and the electron-hole subsystems are
computed as functions of the pumping rate.Comment: version accepted in Phys. Rev.
Praxelis clematidea (Asteraceae,eupatorieae,praxelinae) in Uruguay: First record of the genus and the species
Durante la revisión de las especies del género Praxelis de Sudamérica meridional, poblaciones de P. clematidea fueron halladas en el noroeste de Uruguay. En este trabajo proporcionamos el primer registro del género y la especie para la flora Uruguaya junto con un análisis taxonómico y morfológico basado en ejemplares de herbario y observaciones de campo. Además, se presentan los usos de P. clematidea, su distribución y hábitat, nombres comunes, una ilustración y una clave para diferenciar las especies de Praxelis de Uruguay y áreas circundantes de Argentina y Brasil.During the revision of the southern South American species of Praxelis, populations of P. clematidea were found in northwestern Uruguay. In this study, we provide the first record of the genus and the species for the Uruguayan flora, along with taxonomic and morphological analyses based on herbarium specimens and field observations. In addition, uses of P. clematidea, its distribution and habitat, common names, an illustration and a key to differentiate the species of Praxelis of Uruguay and surrounding areas of Argentina and Brazil are presented.Fil: Salgado, Vanina Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Grossi, Mariana Andrea. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Plantas Vasculares; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Laboratorio de Morfología Comparada de Espermatofitas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: González, Andrés H.. Ministerio de Educación y Cultura. Museo Nacional de Historia Natural; UruguayFil: Gutierrez, Diego Germán. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Laboratorio de Morfología Comparada de Espermatofitas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin
Radial turbine performance measurement under extreme off-design Conditions
[EN] During automotive urban driving conditions and future homologation cycles, automotive radial turbines experience transient conditions, whereby the same operate at very high blade speed ratios and, thus, at very low power outputs. Under those conditions, the turbine power output might not be enough to feed the mechanical power needs of the compressor. Typical fast one-dimensional full engine simulations rely on steady-state performance maps to characterize the turbocharger. Due to the restricting compressor braking power, extreme off-design measurements cannot be obtained in standard gas stands without using an external brake instead of the compressor or without using a motor attached to the turbocharger shaft. Such turbocharger assemblies cause shaft balancing issues inherent to the connection to a brake operating at high rotational speeds or need basic changes of the turbocharger geometry. This paper presents a novel approach for turbine performance map measurements at very low expansion ratio and very low mass flow without the aforementioned issues. The method uses the turbocharger compressor as a centrifugal turbine, providing mechanical power to the shaft and enabling turbine performance measurements from points of very high expansion ratio up to very low pressure ratio. It is even possible to measure at almost zero flow rate in the turbine when it consumes shaft power instead of producing it. This experimental procedure that can be applied to whatever turbocharger produces valuable information for the development and validation of turbine performance models aiming to extrapolate its behaviour at off-design conditions.The authors of this paper wish to thank M.A. Ortiz for his invaluable help during the experimental setup. The work has been partially supported by the Spanish Ministry of Economy and Competitiveness through grant number TRA2013-40853-R.Serrano, J.; Tiseira, AO.; García-Cuevas González, LM.; Inhestern, LB.; Tartoussi, H. (2017). Radial turbine performance measurement under extreme off-design Conditions. Energy. 125:72-84. https://doi.org/10.1016/j.energy.2017.02.118S728412
Insect pheromone research in South America
Insect pheromone research has a long and rich history built up primarily by studies conducted in the Northern hemisphere. Not surprisingly, these studies have largely targeted species relevant to these regions of the world, for the most part agricultural and forest pests. Pheromone research in South American countries came a few decades behind, albeit their strong dependence in agriculture and therefore in pest management. In the last 20 years, a combination of economic, environmental and technical factors have come together to generate a small but rising number of chemical ecologists working in pheromone chemistry and biology in South America. In this article we summarize the results of this trend. We review pheromone studies in which South American scientists have participated in collaboration with foreign scientists, mostly chemistry groups, as well as the ever-growing number of studies carried out completely within the region. We have focused mainly in research involving the characterization of pheromones from native species, which involve the most important insect orders, namely Lepidoptera, Coleoptera, Heteroptera and Hymenoptera. We also present a simple meta-analysis including geographical distribution, trends in collaborative or independent work, and a 20-year evolution of published articles in the field. Finally, we emphasize the importance of a coordinated effort to further promote the growth of this field in Latin America, through the endorsement of international collaborations within the region. Such goal would be facilitated by a regional academic organization, which would in turn initiate the occurrence of regular scientific meetings
Influencia de la rugosidad en la micrudureza y en la resistencia al desgaste de recubrimientos aplicados mediante proyeción térmica
En los recubrimientos depositados por rociado térmico, la rugosidad superficial puede reflejar el grado de fusión y la fuerza con que llegan las partículas al sustrato durante la formación de la capa. Una alta unión de las partículas puede permitir baja porosidad del recubrimiento, lo que se puede traducir en un aumento de sus propiedades mecánicas. Es por esto que el interés de este trabajo se centra en el estudio de la influencia que tiene la rugosidad superficial sobre las propiedades mecánicas y tribológicas de recubrimientos de Níquel, Níquel - Carburo de Tungsteno, Níquel – Carburo de Silicio y Carburo de silicio, con el fin de establecer si los resultados de la medida del perfil de rugosidad superficial ueden reflejar el comportamiento de las propiedades mecánicas y tribológicas de estos recubrimiento
A revised electronic version of RUCAM for the diagnosis of DILI
Background and Aims: Roussel Uclaf Causality Assessment Method (RUCAM) for DILI has been hindered by subjectivity and poor reliability. We sought to improve the RUCAM using data from the Drug-Induced Liver Injury Network (DILIN) and the Spanish DILI Registry, published literature, and it- erative computer modeling.
Approach and Results: RUCAM criteria were updated, clarified, and com- puterized. We removed criteria 3 (risk factors) for lack of added value and cri- teria 4 because we felt it more useful to assess each drug separately. Criteria 6 (drug-specific risk) was anchored to LiverTox likelihood scores. Iterative testing in subsets of 50–100 single-agent, nonherbal cases from both regis- tries was done to optimize performance. We used classification tree analysis to establish diagnostic cutoffs for this revised electronic causality assessment method (RECAM) and compared RECAM with RUCAM for correlation with expert opinion diagnostic categories in 194 DILI cases (98 DILIN, 96 Spanish DILI). Area under receiver operator curves for identifying at least probable DILI were the same at 0.89 for RECAM and RUCAM. However, RECAM diagnostic categories have better observed overall agreement with expert opinion (0.62 vs. 0.56 weighted kappa, p = 0.14), and had better sensitivity to detect extreme diagnostic categories (73 vs. 54 for highly likely or high probable, p = 0.02; 65 vs. 48 for unlikely/excluded, p = 0.08) than RUCAM diagnostic categories.
Conclusions: RECAM is an evidence-based update that is at least as capa- ble as RUCAM in diagnosing DILI compared with expert opinion but is better than RUCAM at the diagnostic extremes. RECAM’s increased objectivity and clarity will improve precision, reliability, and standardization of DILI diagnosis, but further refinement and validation in other cohorts are needed.Funding information
The Drug-Induced Liver Injury (DILN) Network is structured as a U01 cooperative agreement with funds provided by the National Institute
of Diabetes and Digestive and
Kidney Diseases (U24-DK065176, U01-DK065201, U01-DK065184, U01-DK065211, U01DK065193, U01-DK065238, U01-DK083023, U01-DK083027, U01-DK082992, U01-DK083020, and U01-DK100928). Additional support is provided by CTSA grants (UL1 RR025761, UL1TR000083, UL1 RR024134, UL1 RR024986,
UL1 RR024982, UL1 RR024150), the Intramural Research Program of the National Institutes of Health, the National Cancer Institute (ClinicalTrials.gov number: NCT00345930), and the 2016 American Association for the Study of Liver Disease (AASLD) Innovations Fund. The Spanish DILI Registry is funded by grants from Instituto de Salud Carlos III, cofounded by Fondo Europeo de Desarrollo Regional - FEDER (PI 18/01804 and PT 20/00127) and Agencia Española del Medicamento. Plataforma ISCiii de Investigación Clínica and CIBERehd are funded by ISCIII
La Basílica de Pátzcuaro en Pátzcuaro, México: su innovador sistema estructural en la fachada y cubierta
La basílica de Pátzcuaro es el único vestigio del magno proyecto catedralicio que en el S. XVI concibiera Vasco de Quiroga para la diócesis de Michoacán, es en el último tercio de este siglo que la estructura material de la ex catedral y como producto de solicitaciones sísmicas que se dan a través de tres siglos, el edificio presenta modificaciones en su estructura, presentándose las finales en el S. XIX. La vulnerabilidad sísmica obedece a una obra de fábrica de considerable luz, las intervenciones realizadas en el periodo comprendido de 1850 y 1872, básicamente en la fachada y cubierta, muestran la aplicación de los conocimientos de la época, la singularidad de la cubierta de la basílica, consiste en ser el primer edificio histórico que presenta apoyos discontinuos entre la estructura de madera y la corona del muro, interacción que le otorga un comportamiento elástico resultando en un factor de amortiguamiento ante solicitaciones sísmicas. Una singularidad lo constituye la interacción entre la estructura de madera y el mecanismo de apoyo en la corona del muro como una adecuación de la viga de Winkler.5.- Patrimonios Urbano, Rural, Industrial y Religioso. Cementerios Patrimoniales. Técnicas de Evaluación, Limpieza, Reparación y Conservación. Intervenciones en construcciones con patologías estructurales y aplicación de refuerzos
Planck 2015 results. XVIII. Background geometry and topology of the Universe
Cosmology (including clusters of galaxies).-- et al.Maps of cosmic microwave background (CMB) temperature and polarization from the 2015 release of Planck data provide the highestquality full-sky view of the surface of last scattering available to date. This enables us to detect possible departures from a globally isotropic cosmology. We present the first searches using CMB polarization for correlations induced by a possible non-trivial topology with a fundamental domain that intersects, or nearly intersects, the last-scattering surface (at comoving distance χrec), both via a direct scan for matched circular patterns at the intersections and by an optimal likelihood calculation for specific topologies. We specialize to flat spaces with cubic toroidal (T3) and slab (T1) topologies, finding that explicit searches for the latter are sensitive to other topologies with antipodal symmetry. These searches yield no detection of a compact topology with a scale below the diameter of the last-scattering surface. The limits on the radius ℛi of the largest sphere inscribed in the fundamental domain (at log-likelihood ratio Δlnℒ > −5 relative to a simply-connected flat Planck best-fit model) are: ℛi > 0.97 χrec for the T3 cubic torus; and ℛi > 0.56 χrec for the T1 slab. The limit for the T3 cubic torus from the matched-circles search is numerically equivalent, ℛi > 0.97 χrec at 99% confidence level from polarization data alone. We also perform a Bayesian search for an anisotropic global Bianchi VIIh geometry. In the non-physical setting, where the Bianchi cosmology is decoupled from the standard cosmology, Planck temperature data favour the inclusion of a Bianchi component with a Bayes factor of at least 2.3 units of log-evidence. However, the cosmological parameters that generate this pattern are in strong disagreement with those found from CMB anisotropy data alone. Fitting the induced polarization pattern for this model to the Planck data requires an amplitude of −0.10 ± 0.04 compared to the value of + 1 if the model were to be correct. In the physically motivated setting, where the Bianchi parameters are coupled and fitted simultaneously with the standard cosmological parameters, we find no evidence for a Bianchi VIIh cosmology and constrain the vorticity of such models to (ω/H)0 < 7.6 × 10-10 (95% CL).The Planck Collaboration acknowledges the support of: ESA; CNES and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MINECO, JA, and RES (Spain); Tekes, AoF, and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN
(Norway); SFI (Ireland); FCT/MCTES (Portugal); ERC and PRACE (EU).Peer Reviewe
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