Carrere L.C.,National University of Entre Rios |
Tabernig C.B.,National University of Entre Rios
IFMBE Proceedings | Year: 2017
Nowadays, strokes are a growing cause of mortality and many people remain with motor sequelae and troubles in the daily activities. To treat these sequelae, alternative rehabilitation techniques are needed. This article describes the design, development and preliminary evaluation of a system based on Brain Computer Interfaces (BCI) by Motor Imagery, with visual feedback for lower limb rehabilitation of people post stroke. The system consists of three modules: Sensing and Conditioning; Control Signal Generator; and Visual Feedback. The first module acquires, filters and segments 5 channels of EEG. The second module performs spatial filtering using a Laplacian, estimates the signal power spectral density, extracts and selects EEG features which are then used by the classifier to detect event related desynchronization. The command signal generated by the BCI is inputted into the third module, which simulates the movement of foot dorsiflexion of an avatar displayed on a screen. For the implementation, the BCI2000, V-REP platforms and MATLAB software were used. Performance evaluation of the system was done in a healthy volunteer by estimating the sensitivity and specificity, and through interviews with specialists. Average values for sensitivity and specificity were 0,67 and 0,70 respectively, and professional opinions were very good. These results are encouraging for deepening the performance evaluation system and taking steps for clinical implementation. © Springer Nature Singapore Pte Ltd. 2017.
Munitz M.S.,National University of Entre Rios |
Resnik S.L.,University of Buenos Aires |
Resnik S.L.,National University of Central Buenos Aires |
Montti M.I.T.,National University of Entre Rios
Food Chemistry | Year: 2013
Analytical method for the residues of boscalid in blueberries was developed. Fungicide residues were determined by solid-phase microextraction (SPME) coupled to gas chromatography with micro-electron capture (μ-ECD) detector. The effect of pH values and fiber coatings were studied. The SPME fiber coating selected was 100 μm PDMS. The method is selective with adequate precision and high accuracy and sensitivity. Recoveries ranged within the 98-104% range, and detection and quantification limits were 1.33 and 4.42 μg/kg, respectively. Statistical parameters indicated the occurrence of matrix effect; consequently calibration was performed on spiked samples. Degradation of boscalid was studied in a blueberry field located in Concordia, Argentina, with fruits from Emerald and Jewel varieties. The degradation of boscalid in both blueberry varieties studied followed a first order rate kinetics and the half-life for boscalid was 5.3 and 6.3 days for Emerald and Jewel cultivars, respectively. © 2012 Elsevier Ltd. All rights reserved.
Alvez C.,National University of Entre Rios |
Vecchietti A.,INGAR UTN
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011
Nowadays it is common to combine low-level and semantic data for image retrieval. The images are stored in databases and computer graphics algorithms are employed to get the pictures. Most of the works consider both aspects separately. In this work, using the capabilities of a commercial ORDBMS a reference architecture was implemented for recovering images, and then a performance analysis is realized using several index types to search some specific semantic data stored in the database via RDF triples. The experiments analyzed the mean recovery time of triples in tables having a hundred of thousands to millions of triples. The performance obtained using Bitmap, B-Tree and Hash Partitioned indexes are analyzed. The results obtained with the experiences performed are implemented in the reference architecture in order to speed up the pattern search. © 2011 Springer-Verlag.
Sabattini J.A.,National University of Entre Rios
Forest Systems | Year: 2015
Aim of study: The aim of this work was to assess land use and land cover change in Distrito Atencio, near Feliciano, in the province of Entre Ríos, Argentina, from 1984 to 2013 and to make a projection of possible changes in the native forests of Espinal Phytogeographic Region. Area of study: Espinal Ecorregion, Atencio (Argentina) Material and Methods: Ten LANDSAT 5-TM and LANDSAT 8-OLI satellite images were used and two classes were distinguished by vectorization: NF-Native Forests and OL-Other Lands. Besides, four categories were defined by supervised classification: CNFClosed Native Forest, ONF-Open Native Forest, RF-Riverside Forest with Shrub Jungle, and ONG-Open Native Grassland or Savanna. Main results: It was estimated NF as being 76,619 ha and 59,994 ha for years 1984 and 2013 respectively, which represented a 21.69% reduction over a period of 30 years. In 1984, 32.93% of the district surface was occup∫ied by CNF; the same proportion was covered by ONF; and ONG followed with 16.361 ha (20.66%). In 2013, contrarily, CNF was reduced by 13.67%. Land use change was noted to be directed towards the central eastern region. By 2015, OL are expected to keep 88% of their surface, while ONG areas might suffer a 28.80% and 41.25% reduction for years 2025 and 2050 respectively. Research highlights: District's areas with higher incidence on changes due to ecosystem fragmentation processes were identified. It is hoped that this study may contribute to settling native forests protection and recovery areas. © 2015 INIA.
Houspanossian J.,National University of San Luis |
Nosetto M.,National University of San Luis |
Nosetto M.,National University of Entre Rios |
Jobbagy E.G.,National University of San Luis
Global Change Biology | Year: 2013
Land cover changes may affect climate and the energy balance of the Earth through their influence on the greenhouse gas composition of the atmosphere (biogeochemical effects) but also through shifts in the physical properties of the land surface (biophysical effects). We explored how the radiation budget changes following the replacement of temperate dry forests by crops in central semiarid Argentina and quantified the biophysical radiative forcing of this transformation. For this purpose, we computed the albedo and surface temperature for a 7-year period (2003-2009) from MODIS imagery at 70 paired sites occupied by native forests and crops and calculated the radiation budget at the tropopause and surface levels using a columnar radiation model parameterized with satellite data. Mean annual black-sky albedo and diurnal surface temperature were 50% and 2.5 °C higher in croplands than in dry forests. These contrasts increased the outgoing shortwave energy flux at the top of the atmosphere in croplands by a quarter (58.4 vs. 45.9 W m-2) which, together with a slight increase in the outgoing longwave flux, yielded a net cooling of -14 W m-2. This biophysical cooling effect would be equivalent to a reduction in atmospheric CO2 of 22 Mg C ha-1, which involves approximately a quarter to a half of the typical carbon emissions that accompany deforestation in these ecosystems. We showed that the replacement of dry forests by crops in central Argentina has strong biophysical effects on the energy budget which could counterbalance the biogeochemical effects of deforestation. Underestimating or ignoring these biophysical consequences of land-use changes on climate will certainly curtail the effectiveness of many warming mitigation actions, particularly in semiarid regions where high radiation load and smaller active carbon pools would increase the relative importance of biophysical forcing. © 2012 Blackwell Publishing Ltd.
O'Farrell I.,University of Buenos Aires |
Bordet F.,National University of Entre Rios |
Chaparro G.,University of Buenos Aires
Hydrobiologia | Year: 2012
In this study, we analyse the spatial distribution of cyanobacterial summer blooms in a large subtropical reservoir located in the Uruguay River, from 2007 to 2011; these extraordinary algal growth events are mainly represented by scum-forming and nitrogen-fixing eco-strategists of the Dolichospermum and Microcystis genera. The use of the eco-strategists approach, based on ecophysiological work and field observations, allowed us to explain the differences in the distribution pattern and temporal dynamics of both cyanobacterial complexes. Spatial differences were produced due to much higher and fluctuating cyanobacterial abundances at the right margin of the reservoir and at the littoral areas closer to the dam. Satellite imagery (LANDSAT 5 TM) clearly depicted the stronger algal development in the reservoir arms and in the section closer to the dam. The Microcystis spp. complex achieved higher density than the Dolichospermum spp. complex. We hypothesise that the hydrological cycle explains the inter-annual fluctuations of the intensity and frequency of cyanobacterial blooms, and that spatial differences in cyanobacterial presence between the reservoir arms, its margins and the main channel is mainly a response to morphometrical and hydrological characteristics. © 2012 Springer Science+Business Media B.V.
Formento P.C.,National University of Entre Rios
Sensors (Basel, Switzerland) | Year: 2014
Gyroscopes have been proposed as sensors for ambulatory gait analysis and functional electrical stimulation systems. These applications often require detection of the initial contact (IC) of the foot with the floor and/or final contact or foot off (FO) from the floor during outdoor walking. Previous investigations have reported the use of a single gyroscope placed on the shank for detection of IC and FO on level ground and incline walking. This paper describes the evaluation of a gyroscope placed on the shank for determination of IC and FO in subjects ascending and descending a set of stairs. Performance was compared with a reference pressure measurement system. The absolute mean difference between the gyroscope and the reference was less than 45 ms for IC and better than 135 ms for FO for both activities. Detection success was over 93%. These results provide preliminary evidence supporting the use of a gyroscope for gait event detection when walking up and down stairs.
Benintende S.,National University of Entre Rios
Revista Argentina de Microbiologia | Year: 2010
In view of the inoculant production technology available, quality control is a necessary tool to improve soybean inoculants commercialized in Argentina. In 1988, the Facultad de Ciencias Agropecuarias de la Universidad Nacional de Entre Ríos (Argentina) created a quality control service for soybean crop inoculants to offer to farmers. The aim of this study was to evaluate the quality of soybean crop inoculants for seven cropping seasons and to contrast these results with those from previous investigations conducted in our country. This work was developed using 128 inoculant samples from 30 different trade names. The analyzed variables were: inoculant label information, number of viable rhizobia and presence of contaminants. Twenty per cent of the labels showed defects that did not comply with the Argentine legislation. The detected problems in inoculant labels were related to lot numbers or the expiry date, which lacked, was easy to remove or not visible. Eighty seven per cent of the analyzed inoculants were formulated in liquid carriers. Seventy six per cent of the samples had a number of rhizobia above 108 CFU/g or ml, the minimum quantity required by the legislation. Thirty per cent of the analyzed inoculants had contaminants and their presence was related to low rhizobia counts, as shown in a correspondence analysis. The relationship between liquid inoculants and the absence of contaminants was expressed. It can be concluded from the comparison of results found in this investigation with those in previous works published on Argentinean inoculants, that inoculant quality has been improved, although the situation is far from ideal. Adequate manufacturing and commercialization controls are necessary to ensure product quality.
Torres M.E.,National University of Entre Rios |
Colominas M.A.,National University of Entre Rios |
Schlotthauer G.,National University of Entre Rios |
Flandrin P.,Ecole Normale Superieure de Lyon
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2011
In this paper an algorithm based on the ensemble empirical mode decomposition (EEMD) is presented. The key idea on the EEMD relies on averaging the modes obtained by EMD applied to several realizations of Gaussian white noise added to the original signal. The resulting decomposition solves the EMD mode mixing problem, however it introduces new ones. In the method here proposed, a particular noise is added at each stage of the decomposition and a unique residue is computed to obtain each mode. The resulting decomposition is complete, with a numerically negligible error. Two examples are presented: a discrete Dirac delta function and an electrocardiogram signal. The results show that, compared with EEMD, the new method here presented also provides a better spectral separation of the modes and a lesser number of sifting iterations is needed, reducing the computational cost. © 2011 IEEE.
Caviglia O.P.,Instituto Nacional de Tecnologia Agropecuaria |
Caviglia O.P.,National University of Entre Rios |
Melchiori R.J.M.,Instituto Nacional de Tecnologia Agropecuaria
Field Crops Research | Year: 2011
The typical size structuring process that occurs as a consequence of intra-specific competition in maize promotes the appearance of contrasting plant hierarchies (i.e. dominated and dominant individuals). This process may become more intense under low nitrogen (N) availability. The alleviation of plant competition by N addition may reduce plant yield variability through a differential response to N in individuals of contrasting hierarchies. In this work, the response to N of dominated and dominant plants from stands with contrasting N supply (0 to 140-200kgNha-1) was examined on 11 experiments carried out in Paraná, Argentina (31°50'S; 60°31'W) in a broad range of growing conditions that included the variation of the year, genotype, plant population and sowing date. Our objectives were: (i) to evaluate the response to N in contrasting plant hierarchies of maize, (ii) to quantify the contribution of dominated and dominant plants to the response to N of the overall stand, and (iii) to study the effect of N on relationships between plant hierarchies and stand variability. Response to N of yield per plant was associated with biomass per plant in non-fertilized controls, tending to be higher in plants with low biomass. The response to N of yield per unit area (i.e., considering all individuals of the stand) was related to the response to N of dominant and dominated plants (P<0.0001). However, at a higher level of response to N of grain yield per unit area (>50-60%), dominant plants had a considerable lower response than dominated plants, whereas at a lower level of response (<30%), the contribution of contrasting plant hierarchies was similar. In stands with similar plant biomass between hierarchies, the differences in the response to N between plant types tended to be negligible. The coefficient of variation of yield per plant was reduced (P<0.05) by effect of N in 4 out of 11 experiments, although it tended to be consistently lower in fertilized treatments. When the differences between the biomass of dominated and dominant plants were ample we found the highest response to N at the stand level, as a result of the higher increase in grain yield per plant in dominated plants than in dominant ones. The response to N in each plant hierarchy was differentially associated with increases in shoot biomass, harvest index, kernel number per plant and kernel weight. © 2011 Elsevier B.V.