196,412 research outputs found
Attivita’ agricola, valorizzazione enologica e sostenibilità ambientale nel sottobacino Iudeo – Bucari (bacino del fiume Mazaro – TP).
No full textAn approach based on wavelet analysis for feature extraction in the electroretinogram
No full textMost biomedical signals are non-stationary. The knowledge of their frequency content and
temporal distribution is then useful in a clinical context. The wavelet analysis is appropriate
to achieve this task. The present paper uses this method to reveal hidden characteristics
and anomalies of the human a-wave, an important component of the electroretinogram
since it is a measure of the functional integrity of the photoreceptors. We here analyse the
time–frequency features of the a-wave both in normal subjects and in patients affected by
Achromatopsia, a pathology disturbing the functionality of the cones. The results indicate
the presence of two or three stable frequencies that, in the pathological case, shift toward
lower values and change their times of occurrence. The present findings are a first step
toward a deeper understanding of the features of the a-wave and possible applications to
diagnostic procedures in order to recognise incipient photoreceptoral pathologies
WAVELET ANALYSIS OF HUMAN PHOTORECEPTORAL RESPONSE
No full textFeature detection of biomedical signals is crucial for
deepening our knowledge of the physiological phenomena giving
rise to them. To achieve this aim, even if many analytic
approaches have been suggested only few are able to deal with
signals whose features are time dependent, and to provide useful
clinical information. In this work we use the wavelet analysis to
extract peculiarities of the early response of the photoreceptoral
human system, known as a-wave ERG-component. The analysis
of the a-wave features is important since this component reflects
the functional integrity of the two populations of photoreceptors,
rods and cones whose activation dynamics are not well known.
Moreover, in incipient photoreceptoral pathologies the eventual
anomalies in a-wave are not always detectable with a naked eye
analysis of the traces. We here propose the possibility to
discriminate the pathologic from the healthy traces throughout
the differentiation of their time-frequency characteristics,
revealed by the wavelet analysis. The investigated pathologies are
the Achromatopsia, a cone disease and the Congenital Stationary
Night Blindness, a rod trouble. The results show that the number
of stable frequencies present and their times of occurrence are
indicative of the status of the retinal photoreceptors. In
particular, in the pathological cases, the frequency components
shift toward lower values and change their times of occurrence,
with respect to healthy traces
THE EFFECTS OF GROWTH REGULATORS ON IN VITRO AXILLARY SHOOT PROLIFERATION AND ROOTING OF ERICA MULTIFLORA
No full textMultiple shoots were induced on nodal segments of a mature plant of Erica multiflora L. Axillary shoots
produced on uncontaminated explants were excised, segmented, and recultured on the same medium. The
effect of Anderson medium, augmented with different concentrations of 2iP either singly or in combination
with NAA, as potential medium for shoot multiplication by nodal segments was investigated. In the following
experiment equal molar concentrations of four cytokinins (2iP, kinetin, zeatin, and BA) were studied for ability
to induce axillary shoot development from single node stem segments. The highest rate of axillary shoot
proliferation was induced on Anderson medium supplemented with 19.68 μM 2iP and 2.5 g l-1 PhytagelTM.
Four IBA concentrations (0, 0.12, 0.24 or 0.49 μM) were studied to determine the optimum conditions for in
vitro rooting of microshoots. The highest rooting percentage was obtained with IBA at 0.12 and 0.24 mM (72
and 75%, respectively)
ERG signal analysis using wavelet transform
No full textThe wavelet analysis is a powerful tool for analyzing and detecting features of signals characterized by time-dependent statistical properties, as biomedical signals. The identification and the analysis of the components of these signals in the time–frequency domain, give meaningful information about the physiological mechanisms that govern them. This article presents the results of the wavelet analysis applied to the a-wave component of the human electroretinogram. In order to deepen and improve our knowledge about the behavior of the early photoreceptoral response, including the possible activation of interactions and correlations among the photoreceptors, we have detected and identified the stable time–frequency components of the a-wave, using six representative values of luminance. The results indicate the occurrence of three frequencies lying in the range 20–200 Hz. The lowest one is attributed to the summed activities of the photoreceptors. The others are weaker and at low luminance one of them does not occur. We relate them to the response of the rods and the cones whose aggregate activities are non-linear and typically exhibit self-organization under selective stimuli. The identification of the stable frequency components and of their times of occurrence helps us to shine light about the complex mechanisms governing the a-wave. The present results are promising toward the assessment of more refined model concerning the photoreceptoral activities
A comparison among different techniques for human ERG signals processing and classification
No full textA comparison among different techniques for human ERG signals processing and classification ( Articles not published yet, but available online Article in press About articles in press (opens in a new window) )
Barraco, R.a, Persano Adorno, D.a , Brai, M.a, Tranchina, L.b
a Dipartimento di Fisica e Chimica, Università di Palermo and CNISM, Viale delle Scienze, Ed. 18, I-90128 Palermo, Italy
b Laboratorio di Fisica e Tecnologie Relative - UniNetLab, Università di Palermo, Viale delle Scienze, Ed. 18, I-90128 Palermo, Italy
Abstract
Feature detection in biomedical signals is crucial for deepening our knowledge about the involved physiological processes. To achieve this aim, many analytic approaches can be applied but only few are able to deal with signals whose time dependent features provide useful clinical information. Among the biomedical signals, the electroretinogram (ERG), that records the retinal response to a light flash, can improve our comprehension of the complex photoreceptoral activities. The present study is focused on the analysis of the early response of the photoreceptoral human system, known as a-wave ERG-component. This wave reflects the functional integrity of the photoreceptors, rods and cones, whose activation dynamics are not yet completely understood. Moreover, since in incipient photoreceptoral pathologies eventual anomalies in a-wave are not always detectable with a "naked eye" analysis of the traces, the possibility to discriminate pathologic from healthy traces, by means of appropriate analytical techniques, could help in clinical diagnosis. In the present paper, we discuss and compare the efficiency of various techniques of signal processing, such as Fourier analysis (FA), Principal Component Analysis (PCA), Wavelet Analysis (WA) in recognising pathological traces from the healthy ones. The investigated retinal pathologies are Achromatopsia, a cone disease and Congenital Stationary Night Blindness, affecting the photoreceptoral signal transmission. Our findings prove that both PCA and FA of conventional ERGs, don't add clinical information useful for the diagnosis of ocular pathologies, whereas the use of a more sophisticated analysis, based on the wavelet transform, provides a powerful tool for routine clinical examinations of patients. © 2013 Associazione Italiana di Fisica Medica
Fertilización nitrogenada de pasturas de festuca y agropiro
No full textEEA BalcarceEEA General VillegasFil: Mendez, Daniel Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria General Villegas; ArgentinaFil: Barraco, Miriam Raquel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria General Villegas; ArgentinaFil: Berone, German Dario. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentin
Comparison of LIBS and micro-XRF measurements on bronze alloys for monitoring plasma effects
No full textThe laser-induced breakdown spectroscopy (LIBS) technique is often used as atomic
spectroscopic technique for elemental analysis of materials. However, it presents some
drawbacks that make an accurate quantitative analysis difficult. Since the plasma properties,
such as spatial inhomogeneity and plume stoichiometry strongly depend on the experimental
conditions, the measurements are less reproducible. In order to evaluate the measurement
fluctuations, we propose to use the more established micro X-Ray fluorescence (m-XRF)
technique for validating LIBS data. In particular, the quantitative data, obtained by varying the
laser fluence, the shot numbers and the temporal acquisition parameters, were compared with
those obtained by m-XRF on laboratory made samples of binary, ternary and quaternary bronze
alloys. For LIBS measurements a mobile double pulse laser instrument equipped with an high
resolution Echelle type monochromator coupled to an intensified CCD camera was used. m-
XRF analyses were performed with a portable instrument that uses a micro collimated X-Ray
beam and it is equipped with an high resolution detector. The LIBS results show a strong
dependence both on the instrumental set up and the chemical-physical properties of the sample.
With our findings we could identify the most suitable parameters to be used in the investigation
of the different bronze alloys. The possibility to carry out a quantitative analysis by using the
LIBS technique was checked through the comparison with related m-XRF data. In particular in
this paper we identified a set of reliable LIBS parameters for the quantitative analysis of
copper, tin and zinc. Further analyses will be necessary to reach this goal also for the minor
constituents as lea
Investigating the cryopreservation of nodal explants of Lithodora rosmarinifolia (Ten.) Johnst., a rare, endemic Mediterranean species
No full textIn this study, we investigated the possibility of using the droplet-vitrification technique for cryopreserving nodal segments of in vitro plantlets of the endangered plant species Lithodora rosmarinifolia. Among the three vitrification solutions tested, only solutions B1, containing (w/v) 50 % glycerol and 50 % sucrose, and B3, containing 40 % glycerol and 40 % sucrose, were able to induce cryotolerance in nodal explants, resulting in intermediate survival and recovery after cryopreservation. A three-step vitrification protocol, including an additional dehydration treatment with half-strength vitrification solution for 30 min before the treatment with full-strength vitrification solution, did not lead to any improvement in survival and recovery compared with the two-step protocol. The optimal protocol was the following: preculture of nodal segments in liquid medium with 0.3 M sucrose for 16 h and 0.7 M sucrose for 5 h, treatment for 20 min in loading solution containing 1.9 M glycerol + 0.5 M sucrose, dehydration with vitrification solution B1 (glycerol 50.0 %, sucrose 50.0 %, w/v) for 60 min at room temperature, rapid cooling in minute droplets of vitrification solution, and rapid rewarming by immersion of nodal segments for 20 min in unloading solution containing 1.2 M sucrose. Under these conditions, 33 % recovery of cryopreserved nodal explants was achieved. Regrowth of cryopreserved samples was rapid and direct. These results indicate that long-term storage of L. rosmarinifolia by means of cryopreservation of nodal segments is possible, thereby contributing to securing the diversity of this rare and endangered plant species
Forecasting Parking Lots Availability: Analysis from a Real-World Deployment
No full textSmart parking technologies are rapidly being deployed in cities and public/private places around the world for the sake of enabling users to know in real time the occupancy of parking lots and offer applications and services on top of that information. In this work, we detail a real-world deployment of a full-stack smart parking system based on industrial-grade components. We also propose innovative forecasting models (based on CNN-LSTM) to analyze and predict parking occupancy ahead of time. Experimental results show that our model can predict the number of available parking lots in a ±3% range with about 80% accuracy over the next 1-8 hours. Finally, we describe novel applications and services that can be developed given such forecasts and associated analysis
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