597 research outputs found
Combinatorial Topology Of Multipartite Entangled States
With any state of a multipartite quantum system its separability polytope is
associated. This is an algebro-topological object (non-trivial only for mixed
states) which captures the localisation of entanglement of the state.
Particular examples of separability polytopes for 3-partite systems are
explicitly provided. It turns out that this characterisation of entanglement is
associated with simulation of arbitrary unitary operations by 1- and 2-qubit
gates. A topological description of how entanglement changes in course of such
simulation is provided.Comment: 14 pages, LaTeX2e. Slightly revised version of the poster resented on
the International Conference on Quantum Information, Oviedo, Spain, 13-18
July, 2002. To appear in the special issue of Journal of Modern Optic
A Dodecalogue of Basic Didactics from Applications of Abstract Differential Geometry to Quantum Gravity
We summarize the twelve most important in our view novel concepts that have
arisen, based on results that have been obtained, from various applications of
Abstract Differential Geometry (ADG) to Quantum Gravity (QG). The present
document may be used as a concise, yet informal, discursive and peripatetic
conceptual guide-cum-terminological glossary to the voluminous technical
research literature on the subject. In a bonus section at the end, we dwell on
the significance of introducing new conceptual terminology in future QG
research by means of `poetic language'Comment: 16 pages, preliminary versio
Loop quantum black hole
In this paper we consider the Kantowski-Sachs space-time in Ashtekar
variables and the quantization of this space-time starting from the complete
loop quantum gravity theory. The Kanthowski-Sachs space-time coincides with the
Schwarzschild black hole solution inside the horizon. By studying this model we
can obtain information about the black hole singularity and about the dynamics
across the point r=0. We studied this space-time in ADM variables in two
previous papers where we showed that the classical black hole singularity
disappears in quantum theory. In this work we study the same model in Ashtekar
variables and we obtain a regular space-time inside the horizon region and that
the dynamics can be extend further the classical singularity.Comment: 12 pages, latex. We introduce and we calculate the spectrum of the
operator 1/|E
Experimental study of the turbulent structure of the surface marine Atmospheric Boundary Layer over the Aegean Pelagos under etesian winds
In order to study the physical processes of the turbulent transportation of mass and energy within the surface Marine Atmospheric Boundary Layer over the Aegean Pelagos, field measurements were conducted on the island of Skyros, mainly under the etesian winds, during summer 2011. Α meteorological mast was installed close to the shoreline, instrumented with fast anemometer (sonic) and hydrometer measuring the three components of the wind, the virtual temperature and water vapor at 10m height with a sampling frequency of 20Hz. At the same mast slow response sensors were measuring wind speed and direction, temperature and humidity at three levels (2, 6 and 10 m). Weak stable to near neutral flows were recorded during the experimental period. The eddy correlation analysis re-vealed the momentum and heat fluxes values which are presented and discussed. The estimated values are related both with stability and wind speed variations
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Assessment of surface solar irradiance derived from real-time modelling techniques and verification with ground-based measurements
This study focuses on the assessment of surface solar radiation (SSR) based on operational neural network (NN) and multi-regression function (MRF) modelling techniques that produce instantaneous (in less than 1 min) outputs. Using real-time cloud and aerosol optical properties inputs from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board the Meteosat Second Generation (MSG) satellite and the Copernicus Atmosphere Monitoring Service (CAMS), respectively, these models are capable of calculating SSR in high resolution (1 nm, 0.05 degree, 15 min) that can be used for spectrally integrated irradiance maps, databases and various applications related to energy exploitation. The real-time models are validated against ground-based measurements of the Baseline Surface Radiation Network (BSRN) in a temporal range varying from 15 min to monthly means, while a sensitivity analysis of the cloud and aerosol effects on SSR is performed to ensure reliability under different sky and climatological conditions. The simulated outputs, compared to their common training dataset created by the radiative transfer model (RTM) libRadtran, showed median error values in the range −15 to +15 % for the NN that produces spectral irradiances (NNS), 5–6 % underestimation for the integrated NN and close to zero errors for the MRF technique. The verification against BSRN revealed that the real-time calculation uncertainty ranges from −100 to +40 and −20 to +20 W/m^2, for the 15 min and monthly mean global horizontal irradiance (GHI) averages, respectively, while the accuracy of the input parameters, in terms of aerosol and cloud optical thickness (AOD and COT), and their impact on GHI, was of the order of 10 % as compared to the ground-based measurements. The proposed system aims to be utilized through studies and real-time applications which are related to solar energy production planning and use
Abdominoperineal Resection for Rectal Cancer: Is the Pelvic Drain Externalization Site an Independent Risk Factor for Perineal Wound Healing?
Aim. The aim of this paper is to investigate if the insertion of the pelvic drainage tube via the perineal wound could be considered as an independent risk factor for perineal healing disorders, after abdominoperineal resection for rectal malignancy. Patients and Methods. The last two decades, 75 patients underwent elective abdominoperineal resection for malignancy. In 42 patients (56%), the pelvic drain catheter was inserted through the perineal wound (PW group), while in the remaining 33 (44%) through a puncture skin wound of the perineum (SW group). Patients' data with respect to age (P = 0.136), stage (P > 0.05), sex (P = 0.188) and comorbidity (P = 0.128) were similar in both groups. 25 patients (PW versus SW: 8 versus 17, P = 0.0026) underwent neoadjuvant radio/chemotherapy.
Results. The overall morbidity rate was 36%, but a significant increase was revealed in PW group (52.4% versus 9%, P = 0.0007). In 33.3% of the patients in the PW group, perineal healing was delayed, while in the SW group, no delay was noted. Perineal healing disorders were revealed as the main source of increased morbidity in this group. Conclusion. The insertion of the pelvic drain tube through the perineal wound should be considered as an independent risk factor predisposing to perineal healing disorders
rac-5-Acetyl-6-hydroxy-3,6-dimethyl-4-phenyl-2H-4,5,6,7-tetrahydroindazol-1-ium chloride
The structure of the title compound, C17H21N2O2
+·Cl−, is of interest with respect to its biological activity. The title compound comprises an organic cation and a chloride anion in the asymmetric unit. The positive charge is localized in a pyrazole moiety forming a pyrazolium cation. The structure displays intermolecular O—H⋯Cl and N—H⋯Cl hydrogen bonding
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