1,956 research outputs found
Weakly open sets in the unit ball of some Banach spaces and the centralizer
AbstractWe show that every Banach space X whose centralizer is infinite-dimensional satisfies that every non-empty weakly open set in BY has diameter 2, where Y=⊗ˆN,s,πX (N-fold symmetric projective tensor product of X, endowed with the symmetric projective norm), for every natural number N. We provide examples where the above conclusion holds that includes some spaces of operators and infinite-dimensional C∗-algebras. We also prove that every non-empty weak∗ open set in the unit ball of the space of N-homogeneous and integral polynomials on X has diameter two, for every natural number N, whenever the Cunningham algebra of X is infinite-dimensional. Here we consider the space of N-homogeneous integral polynomials as the dual of the space ⊗ˆN,s,εX (N-fold symmetric injective tensor product of X, endowed with the symmetric injective norm). For instance, every infinite-dimensional L1(μ) satisfies that its Cunningham algebra is infinite-dimensional. We obtain the same result for every non-reflexive L-embedded space, and so for every predual of an infinite-dimensional von Neumann algebra
Threshold volatility models: forecasting performance
The aim of this paper is to compare the forecasting performance of competing
volatility models, in order to capture the asymmetric effect in the volatility.
We focus on examining the relative out-of-sample forecasting ability of the models
(SETAR-TGARCH and SETAR-THSV), which contain the introduction of regimes
based on thresholds in the mean equation and volatility equation, compared to the
GARCH model and SV model. For each model, we consider two cases: Gaussian and
t-Student measurement noise distribution. An important problem when evaluating
the predictive ability of volatility models is that the “true” underlying process is
not observable and thus a proxy must be defined for the unobservable volatility. To
attain our proposal, the proxy volatility measure and the loss function must also be
decided to ensure a correct ranking of models.
Our empirical application suggests the following results: when time series include
leverage effects on the mean, the introduction of threshold in the mean and variance
equations produces more accurate predictions. If the leverage in the mean is not
important, then the SVt is flexible enough to beat the threshold models.Peer ReviewedPostprint (published version
Spanish facilities and fisrst results in measuring thermodynamic temperature using the radiance method
Newport Pagnell, Buckinghamshire, May 18-19 2015; https://royalsociety.org/science-events-and-lectures/2015/05/new-kelvin/Currently, the dissemination of the kelvin, according to the International Temperature Scale (ITS-90), at high temperatures is realised at the Centro Español de Metrología (CEM) by using the fixed points of Ag and Cu and a standard radiation thermometer. Recently, absolute radiometry has been proposed by the CCT Working Group 5 [1] to be included in future revisions of the Mise-en-Practique for the kelvin (MeP-K). The Centro Español de Metrologia (CEM) in collaboration with the Instituto de Óptica of the Consejo Superior de Investigaciones Científicas (IO-CSIC) has been working in the following lines linked to this new alternative to disseminate the kelvin:
¿ Absolute calibration, i.e., calibration in terms of the thermodynamic temperature, of commercial radiation thermometers, by using a facility based on a monochromator and a high stability lamp [2]. At present, the uncertainties of these measurements, obtained with a KE-LP2 radiation thermometer, are about the ones obtained with the ITS-90 method, i. e. from 0,3 K to 1,1 K (from 1084,62 °C to 2474 °C, k = 2). Some improvements in the facilities described in [2] have been implemented in order to reduce uncertainty.
¿ Development of a filter radiometer to measure the thermodynamic temperature. It has been designed by CEM based in NPL previous work [3]. This filter radiometer can be calibrated with a laser based experimental setup, which improves the above measurement uncertainty [4]: from 0,2 K to 0,7 K (from 1084,62 °C to 2474 °C, k = 2). Because of some problems with the radiometer stability at 2500 °C, some changes in the design have been done.
The facilities used in [2] and [4] are currently been developed at CEM site as the transportation of the instruments for calibration has caused significant drifts. A complete description of IO-CSIC and new CEM facilities will be presented, together with the results obtained on the determination of the WP1 InK cells thermodynamic temperatures by using both, a radiation thermometer with an absolute calibration, and a filter radiometer.Peer Reviewe
Episodic displacement on a sackung scarp in Benasque Valley (Central Spanish Pyrenees). Paleoseismic record?
A sackung scarp has been investigated by trenching in the El Ubago glacial valley (central Spanish Pyrenees). The scarp is located 18 km to the SW of the North Maladeta Fault, which was the source of the Mw 5.3 Vielha earthquake of 1923. Three displacement events have been inferred based on colluvial wedge stratigraphy and fault truncation. Event X at ca. 16.9 ka created the sackung. Events Y and Z have been constrained at 15-8.3 and 8.3-5.3 ka. The timing of event Y partially overlaps with that of a faulting event recognised in a previously investigated sackung at about 2 km. A minimum vertical slip rate of 0.18 mm/yr has been calculated for the sackung. The spatial association of the sackung features in this sector of the Pyrenees with the North Maladeta Fault and the millennial recurrence of the inferred displacement events (5.6 kyr) suggests that the kinematics of the studied sackung has been controlled by seismic activity. Demonstrating in future investigations that the sackung features in the area constitute archives of large paleoearthquake would be of great interest for seismic hazard assessments. They might help to improve the catalogue of paleoearthquakes and might provide information on earthquake recurrence intervals and the age of the MRE
Planeación estratégica de la empresa Andrews en el simulador de negocios Capstone
En este documento se describen y analizan las estrategias de negocio implementadas en la empresa Andrews dentro del simulador de negocios Capstone. De igual forma, se presentan los resultados en un periodo de simulación de ocho años en los departamentos de mercadotecnia, investigación y desarrollo, finanzas, producción, recursos humanos y calidad
POTENTIAL INCLUSION OF MACARONESIAN SEAWEED WRACKS IN DIETS FOR GILTHEAD SEABREAM (SPARUS AURATA).
Morphobathymetry and formation processes of sediment waves in the Gulf of Valencia continental slope (NW Mediterranean)
Versión del edito
Diversity for chemical composition in a collection of different varietal types of tree tomato (Solanum betaceum Cav.), an Andean exotic fruit
[EN] We evaluated 23 tree tomato (Solanum betaceum) accessions from five cultivar groups and one wild relative (Solanum cajanumense) for 26 composition traits. For all traits we found highly significant differences (P < 0.001) among the materials studied. The high diversity found within S. betaceum for composition traits was matched by a high diversity within each of the cultivar groups. We found that sucrose and citric acid were the most important soluble sugar and organic acid, respectively, in tree tomato. Fruit in the anthocyanin pigmented (purple) group had a carotenoid content similar to that in the yellow-orange cultivar groups. Total phenolic content was significantly correlated (r = 0.8607) with antioxidant activity. Analyses of mineral content showed that tree tomato is a good source of K, Mg, and Cu. Multivariate principal components analysis (PCA) confirmed that an important diversity exists within each cultivar group. The results we have obtained indicate that the high diversity found within the tree tomato could be exploited for selection and breeding for developing the tree tomato as a commercial crop. (C) 2014 Elsevier Ltd. All rights reserved.This work was partially financed by the Ecuadorian Secretaria Nacional de Educacion Superior, Ciencia, Tecnologia e Innovacion from Ecuador (SENESCYT).Acosta-Quezada, P.; Raigón Jiménez, MD.; Riofrío-Cuenca, T.; García Martínez, MD.; Plazas Ávila, MDLO.; Burneo, J.; Figueroa, JG.... (2015). Diversity for chemical composition in a collection of different varietal types of tree tomato (Solanum betaceum Cav.), an Andean exotic fruit. Food Chemistry. 169:327-335. doi:10.1016/j.foodchem.2014.07.152S32733516
Association of Neck Circumference with Anthropometric Indicators and Body Composition Measured by DXA in Young Spanish Adults
Background: Due to a clinical and public health interest of neck circumference (NC),
a better understanding of this simple anthropometric measurement, as a valid marker of body
composition is necessary. Methods: A total of 119 young healthy adults participated in this study.
NC was measured over the thyroid cartilage and perpendicular to the longitudinal axis of the neck.
Body weight, height, waist circumference (WC), and hip circumference were measured. A Dual
X-ray absorptiometry (DXA) scan was used to determine fat mass, lean mass, and visceral adipose
tissue (VAT). Additionally, body mass index (BMI) and triponderal mass index (TMI), the waist to
hip and waist to height ratios, and the fat mass and lean mass indexes (FMI and LMI, respectively)
were calculated. Results: NC was positively associated in women (W) and men (M), with BMI (rW
= 0.70 and rM = 0.84, respectively), TMI (rW = 0.63 and rM = 0.80, respectively), WC (rW = 0.75
and rM = 0.86, respectively), VAT (rW = 0.74 and rM = 0.82, respectively), Waist/hip (rW = 0.51
and rM = 0.67, respectively), Waist/height (rW = 0.68 and rM = 0.83, respectively) and FMI (rW =
0.61 and rM = 0.81, respectively). The association between NC and indicators of body composition
was however weaker than that observed by BMI, TMI, WC and Waist/height in both women and
men. It is of note that in women, NC was associated with FMI, VAT and LMI independently of BMI.
In men, adding NC to anthropometric variables did not improve the prediction of body composition,
while slight improvements were observed in women. Conclusions: Taken together, the present
study provides no indication for NC as a useful proxy of body composition parameters in young
adults, yet future studies should explore its usefulness as a measure to use in combination with BMI,
especially in women.This study was supported by the Spanish Ministry of Economy and Competitiveness Grants
(DEP2016-79512-R and PTA 12264-I), Fondo de Investigación Sanitaria del Instituto de Salud Carlos III (PI13/01393),
and Retos de la Sociedad (DEP2016-79512-R), Fondos Estructurales de la Unión Europea (FEDER), by the
Spanish Ministry of Education (FPU 13/04365), by the Fundación Iberoamericana de Nutrición (FINUT), by the
Redes temáticas de investigación cooperativa RETIC (Red SAMID RD16/0022), by AstraZeneca HealthCare
Foundation and by the University of Granada, Plan Propio de Investigación 2016, Excellence actions: Units
of Excellence; Scientific Unit of Excellence on Exercise and Health (UCEES), Plan Propio de Investigación
2018: Programa Contratos-Puente and Programa Perfeccionamiento de Doctores, by the Junta de Andalucía,
Consejería de Conocimiento, Investigación y Universidades, the European Regional Development Funds (ref.
SOMM17/6107/UGR), by the Fundación Alfonso Martín Escudero, and by the Fundación Carolina (C.2016-574961).
This study is part of a Ph.D. Thesis conducted in the Biomedicine Doctoral Studies of the University of
Granada, Spain
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