469 research outputs found
Migration strategies toward all optical metropolitan access rings
This paper was published in Journal of Lightwave Technology
and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the IEEE website: http://dx.doi.org/10.1109/JLT.2007.901325. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Nowadays, network operators are steadily deploying optical circuit switching (OCS) equipment in their metropolitan networks in order to cope with traffic increase and, most importantly, in order to reduce capital expenditures and operational expenditures of existing active technologies. On the other hand, optical burst switching (OBS) technology is expected to become mature in the medium term, and it may be used as an alternative to current OCS networks due to its potential advantages in terms of bandwidth allocation granularity. While OBS is being extensively studied in the literature, little attention has been paid in conducting a comparative analysis of OBS versus OCS, especially concerning cost analysis. In this paper, we provide a comparative analysis of OBS versus OCS as an evolutionary technology for all-optical rings in the metropolitan-access network. This paper is specifically targeted toward optimizing the number of optoelectronic receivers and wavelengths with real traffic matrices from the metropolitan rings in Madrid, Spain. Such matrices also include traffic projections of foreseeable broadband services, which are based on a market analysis from the largest operator in Spain. Our findings show that OCS might be more efficient than OBS in the metro-access segment, which is characterized by a highly centralized traffic pattern. However, the more distributed the traffic is, the more efficient the OBS is as well. Consequently, OBS might be better suited to metro-core networks, which show a more distributed and dynamic traffic pattern.The authors would like to thank the e-Photon/ONe+ network
of excellenc
Ultrasound-assisted extraction of anthocyanins and total phenolic compounds in Vitis vinifera L. 'Tempranillo' winemaking lees
Winemaking lees (WL) are the less exploited by-products from the winemaking industry. This by-product is generated after the fermentation of grape must and its composition is variable, although it is mainly made up of lysed yeasts, tartaric acid, colloids, polyphenols and ashes. Of all the compounds that can be found in lees, polyphenols exhibit particularly powerful bioactive properties and their extraction for their reuse in different matrices could be a matter of particular interest.Ultrasound-assisted extraction (UAE) has been used to extract both total anthocyanins (TA) and total phenolic compounds (TPC) from lees from Vitis vinifera L. 'Tempranillo' vinification. The optimization of six extraction variables (% methanol, pH, temperature, amplitude, cycle and ratio solvent:mass) was performed using a Box-Behnken design (BBD) where TA and TPC were considered independent variables. The UAE method that has been developed in this research could be a new rapid and efficient method to extract TPC and, coupled to chromatographic methodologies, identify up to fourteen different anthocyanins from WL. The objective of this study is to determine WL polyphenolic content and its potential for further uses in other procedures aiming to create value from vinification waste
Impact of plot size and model selection on forest biomass estimation using airborne LiDAR: A case study of pine plantations in southern Spain
We explored the usefulness of LiDAR for modelling and mapping the stand biomass of two conifer species in southern Spain.
We used three different plot sizes and two statistical approaches (i.e. stepwise selection and genetic algorithm selection) in
combination with multiple linear regression models to estimate biomass. 43 predictor variables derived from discrete-return
LiDAR data (4 pulses per m2
) were used for estimating the forest biomass of Pinus sylvestris Linnaeus and Pinus nigra Arnold
forests. Twelve circular plots – six for each species – and three different fixed-radius designs (i.e. 7, 15, and 30 m) were estab lished within the range of the airborne LiDAR. The Bayesian information criterion and R2
were used to select the best models.
As expected, the models that included the largest plots (30 m) yielded the highest R2
value (0.91) for Pinus sp. using genetic
algorithm models. Considering P. sylvestris and P. nigra models separately, the genetic algorithm approach also yielded the
highest R2
values for the 30-m plots (P. nigra: R2 = 0.99, P. sylvestris: R2
= 0.97). The results we obtained with two species and
different plot sizes revealed that increasing the size of plots from 15 to 30 m had a low effect on modelling attempts.European Commission (EC) FP7-315165Ministerio de Economía, Industria y Competitividad QUERCUSAT (CLG2013-40790-R
Evolutionary feature selection to estimate forest stand variablesusing LiDAR
Light detection and ranging (LiDAR) has become an important tool in forestry. LiDAR-derived models are mostly developed by means of multiple linear regression (MLR) after stepwise selection of predictors. An increasing interest in machine learning and evolutionary computation has recently arisen to improve regression use in LiDAR data processing. Although evolutionary machine learning has already proven to be suitable for regression, evolutionary computation may also be applied to improve parametric models such as MLR. This paper provides a hybrid approach based on joint use of MLR and a novel genetic algorithm for the estimation of the main forest stand variables. We show a comparison between our genetic approach and other common methods of selecting predictors. The results obtained from several LiDAR datasets with different pulse densities in two areas of the Iberian Peninsula indicate that genetic algorithms perform better than the other methods statistically. Preliminary studies suggest that a lack of parametric conditions in field data and possible misuse of parametric tests may be the main reasons for the better performance of the genetic algorithm. This research confirms the findings of previous studies that outline the importance of evolutionary computation in the context of LiDAR analisys of forest data, especially when the size of fieldwork datatasets is reduced.Ministerio de Ciencia y Tecnología TIN2007- 68084-C-00Ministerio de Ciencia y Tecnología TIN2011-28956-C02Xunta de Galicia 09MRU022291PXunta de Galicia CGL2011-30285-C02-02Xunta de Galicia FP7-SME-2011-BS
Strain-induced enhancement of the thermoelectric power in thin films of hole-doped La2NiO4+δ
We propose a novel route for optimizing the thermoelectric power of a polaronic conductor, independent of its electronic conductivity. This mechanism is exemplified here in thin-films of La2NiO4+δ. Tensile stress induced by epitaxial growth on SrTiO3 doubles the thermoelectric power of ≈15 nm thick films relative to ≈90 nm films, while the electronic conductivity remains practically unchanged. Epitaxial strain influences the statistical contribution to the high temperature thermopower, but introduces a smaller correction to the electronic conductivity. This mechanism provides a new way for optimizing the high temperature thermoelectric performance of polaronic conductorsThis work was supported by the European Research Council (ERC StG-259082, 2DTHERMS), and Ministerio de Economía y Competitividad of Spain through the project MAT2010-16157, and a Ph.D. grant of the FPI program (J.M.V.-F.)S
The Latin American Dialysis and Renal Transplantation Registry: report 2019
Background Chronic kidney disease (CKD) in Latin America (LA) continues to represent a challenge due to the burden of disease it causes and the difficulty in accessing treatment. LA has a total population of 652 million people living in 20 countries that occupy an area of 19.2 million km2. The Latin American Dialysis and Renal Transplantation Registry (LADRTR), founded in 1991, has collected data and reports on patients receiving kidney replacement therapy (KRT) since 1993. This article summarizes the registry data for 2019. Methods Participating countries complete an annual survey collecting aggregated data on incident and prevalent patients on KRT in all modalities. The different treatment modalities considered were hemodialysis (HD), peritoneal dialysis (PD) and living functioning kidney graft (LFG). National gross domestic product per capita (GDP, expressed in US dollars) and life expectancy at birth (LEB) corresponding to the year 2019 were collected from the World Bank Data Bank. Prevalence and incidence were compared with previous years and were also correlated with GDP and LEB. Results On 31 December 2019 a total of 432 610 patients were in KRT in LA, corresponding to an overall unadjusted prevalence of 866 per million population (pmp). Regarding treatment modality, 66.7% of the prevalent patients were treated with HD and 9.3% with PD while 24% of the patients had an LFG. A total of 85 224 patients started KRT in LA, representing a total unadjusted incidence rate of 168 pmp. Diabetic nephropathy as a cause of CKD continues to be a relevant percentage (36%) and five countries reported CKD of nontraditional causes. The kidney transplant rate in the region was 22 pmp, varying from 1 to >60 pmp. The total prevalence of KRT correlated positively with GDP per capita (r2 = 0.6, P < 0.01) and LEB (r2 = 0.23, P < 0.05). The overall incidence rate also significantly correlated with GDP (r2 = 0.307, P < 0.05). The overall unadjusted mortality rate was 13%. Conclusion Accessibility to KRT is still limited in LA. It is necessary to continue the efforts made by each country and the Latin American Society of Nephrology and Hypertension to guarantee equal access to treatment
Effects of D-003, a mixture of high-molecular-weight sugar cane wax acids, on lipid peroxidation markers in older individuals: A randomized, double-blind, placebo-controlled study
AbstractBackground: Aging is associated with increased lipid peroxidation (LP). D-003, a mixture of long-chain aliphatic primary acids purified from sugar cane wax, has been found to inhibit LP in experimental models and in healthy subjects.Objectives: The aim of this study was to assess the effects of D-003 on LP markers and the lipid profile of older individuals.Methods: This randomized, double-blind, placebo-controlled study was conducted at the Plaza Veterans' House, Havana City, Cuba. Male and female patients aged ≥60 years with total cholesterol values of <6.1 mmol/L were eligible for inclusion in the study. After a 3-week lead-in and baseline assessment period, patients were randomized to receive PO D-003 5 mg/d, D-003 10 mg/d, or placebo for 8 weeks. The effect on copper-induced LP of low-density lipoprotein (LDL) particles was the primary variable, and the effects on plasma total antioxidant status (TAS), plasma malondialdehyde (MDA) concentration, plasma antioxidant enzyme (superoxide dismutase and glutathione peroxidase) activities, and the lipid profile were secondary variables. A clinical examination was performed at each visit (baseline, weeks 4 and 8). A clinical examination, LP, and blood tests (lipid profile, hematologic, and blood biochemistry safety indicators) were performed at baseline and after 8 weeks of treatment. Compliance and adverse events (AEs) were assessed at weeks 4 and 8. A 2-tailed P < 0.05 was considered statistically significant for comparisons of both continuous and categoric variables.Results: Fifty-four patients aged ≥60 years were assessed for inclusion in the study, and 51 patients (40 women, 11 men; mean [SD] age, 67 [6] years) were included in the study. The lag phase of conjugated diene formation increased significantly and in a dose-dependent manner in the group treated with D-003 5 mg (24.7%; P < 0.01) and in the group treated with D-003 10 mg (29.3%; P < 0.01) compared with placebo. The maximal rate of conjugated diene propagation decreased significantly in the D-003 5- and 10-mg groups −22.7% and −25.8%, respectively; both, P < 0.05) compared with placebo. TAS increased significantly (17.7% and 23.0%, respectively; both, P < 0.01) in both active treatment groups compared with placebo. Plasma MDA concentration decreased significantly in the D-003 10-mg group (−28.6%; P < 0.05) but not in the D-003 5-mg group, compared with placebo. These changes were also significant compared with baseline. Antioxidant enzyme activities did not change in the active treatment groups compared with placebo or baseline. In the D-003 5- and 10-mg groups, significant decreases were found in LDL cholesterol concentration (−15.8% and −23.8%, respectively; both, P < 0.001) and total cholesterol concentration (−13.0% and −16.8%, both, P < 0.05) compared with placebo. High-density lipoprotein cholesterol concentration increased significantly in the D-003 5-mg group (5.7%; P < 0.05) and the D-003 10-mg group (18.2%; P < 0.001) compared with placebo. Changes in the lipid profile were also significant compared with baseline. In the placebo group, no variable changed significantly compared with baseline. D-003 was well tolerated at both dose levels, and no patient withdrew from the study. There were a total of 3 AEs reported: insomnia and acidity in 2 patients receiving placebo; and heartburn in 1 patient receiving D-003 5 mg.Conclusions: D-003 5 and 10 mg/d administered to these older individuals (aged ≥60 years) for 8 weeks inhibited LP of LDL and increased TAS in a dose-dependent manner, while plasma MDA concentration decreased in the patients receiving D-003 10 mg/d only. D-003 was well tolerated at both dose
Multicolor photometry of ten Seyfert 1 galaxies
We present BVI photometry of ten Seyfert 1 galaxies and narrow band H-alpha
images for six of these objects as well. The results indicate that the
luminosity sample distribution has an amplitude of almost 4 magnitudes with an
average of M_B=-20.7. The observed morphologies are confined to early type
galaxies. A barred structure is found in only 2 objects. Despite that early
morphological types are dominant in this sample, integrated (B-V) colors are
very blue. For instance, the SO galaxies show, on average, a (B-V)=0.78. This
effect seems to be caused by the luminosity contribution of the active nucleus
and/or the disk to the total luminosity of the galaxy. In the B band, the
contribution of the active galactic nucleus to the total luminosity of the
galaxy varies from 3% to almost 60% and the bulge to disk luminosity ratio
(L_bulge/L_disk) ranges from 0.6 to 22. Signs of tidal interactions seems to be
a common characteristic since they are observed in 6 of the objects and one of
them seems to be located in a poor cluster not yet identified in the
literature. H_alpha extended emission is rare, with only 1 galaxy showing clear
evidence of it. Luminosity profile decomposition shows that the model Gauss +
bulge + disk properly reproduces the surface brightness of the galaxies.
However, in order to account for the luminosity profile, most of the disk
galaxies needs the inner truncated exponential form with a central cutoff
radius ranging from 3 to 10 kpc. This is interpreted in terms of reddened
regions that are well identified in the B-V color maps. These regions present
very similar colors among them, with (B-V)~1.2. This fact could be associated
to the presence of dust confined in the inner regions of the galaxies.Comment: 14 pages, 25 figures. Accepted to Astronomy & Astrophysic
Identificación de los Indicadores de seguimiento de las acciones de conservación. Acción A1 “Diagnosis, Análisis territorial e Identificación de Indicadores"
Las acciones de conservación de LIFE FLUVIAL precisan de una evaluación periódica
de sus repercusiones sobre el hábitat 91E0* y el hábitat 9230 (los dos hábitats objetivo
del proyecto). Cada socio en sus territorios debe llevar a cabo un seguimiento con motivo
de la acción D1 que permita evaluar la efectividad de las actuaciones de restauración
(acciones C) y realizar una toma de decisiones de acuerdo a los resultados de dicho
monitoreo, que pueda incluir cambios en las actuaciones previstas o la ejecución de
nuevas medidas.
En consecuencia, en el presente documento se establecen los indicadores de
seguimiento a emplear en la acción D1 de LIFE FLUVIAL, así como la metodología para su
aplicación. Los objetivos del seguimiento son:
A. Vigilar la evolución del proceso de restauración
B. Controlar los cambios que se produzcan
C. Detectar y corregir la aparición de efectos indeseables
D. Favorecer los procesos que se entiendan beneficiosos para recuperar la
naturalidad y biodiversidad del lugar.
En todo caso, hay que tener en cuenta que la duración del proyecto se queda corta
para poder abarcar todo el proceso de recuperación de la cubierta vegetal propiciado por
las acciones de conservación, de modo que, probablemente, los resultados del
seguimiento relativos a algunos parámetros no presentarán valores especialmente
significativos, debiendo interpretarse entonces como tendencias de la evolución de los
hábitats objetivo en los enclaves de actuación.info:eu-repo/semantics/publishedVersio
Agroforestry in the European common agricultural policy
Agroforestry is a sustainable land management system that should be more strongly promoted in Europe to ensure adequate ecosystem service provision in the old continent (Decision 529/2013) through the common agricultural policy (CAP). The promotion of the woody component in Europe can be appreciated in different sections of the CAP linked to Pillar I (direct payments and Greening) and Pillar II (rural development programs). However, agroforestry is not recognised as such in the CAP, with the exception of the Measure 8.2 of Pillar II. The lack of recognition of agroforestry practices within the different sections of the CAP reduces the impact of CAP activities by overlooking the optimum combinations that would maximise the productivity of land where agroforestry could be promoted, considering both the spatial and temporal scales
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