5 resultados para Projective synchronization
em AMS Tesi di Laurea - Alm@DL - Università di Bologna
Resumo:
Analisi e sviluppo di procedure di importazione dati per un integratore di annunci immobiliari dedicato alla vendita di soggiorni turistici in case vacanza. Il documento tratta inoltre l'implementazione di un Web Service conforme all'architettura RESTful per l'accesso e l'esportazione dei dati a soggetti terzi autorizzati tramite Digest Authentication.
A Phase Space Box-counting based Method for Arrhythmia Prediction from Electrocardiogram Time Series
Resumo:
Arrhythmia is one kind of cardiovascular diseases that give rise to the number of deaths and potentially yields immedicable danger. Arrhythmia is a life threatening condition originating from disorganized propagation of electrical signals in heart resulting in desynchronization among different chambers of the heart. Fundamentally, the synchronization process means that the phase relationship of electrical activities between the chambers remains coherent, maintaining a constant phase difference over time. If desynchronization occurs due to arrhythmia, the coherent phase relationship breaks down resulting in chaotic rhythm affecting the regular pumping mechanism of heart. This phenomenon was explored by using the phase space reconstruction technique which is a standard analysis technique of time series data generated from nonlinear dynamical system. In this project a novel index is presented for predicting the onset of ventricular arrhythmias. Analysis of continuously captured long-term ECG data recordings was conducted up to the onset of arrhythmia by the phase space reconstruction method, obtaining 2-dimensional images, analysed by the box counting method. The method was tested using the ECG data set of three different kinds including normal (NR), Ventricular Tachycardia (VT), Ventricular Fibrillation (VF), extracted from the Physionet ECG database. Statistical measures like mean (μ), standard deviation (σ) and coefficient of variation (σ/μ) for the box-counting in phase space diagrams are derived for a sliding window of 10 beats of ECG signal. From the results of these statistical analyses, a threshold was derived as an upper bound of Coefficient of Variation (CV) for box-counting of ECG phase portraits which is capable of reliably predicting the impeding arrhythmia long before its actual occurrence. As future work of research, it was planned to validate this prediction tool over a wider population of patients affected by different kind of arrhythmia, like atrial fibrillation, bundle and brunch block, and set different thresholds for them, in order to confirm its clinical applicability.
Resumo:
The present study was conducted to investigate the influence of restricted food access on Solea senegalensis behaviour and daily expression of clock genes in central (diencephalon and optic tectum) and pheripheral (liver) tissues. The Senegalese sole is a marine teleost fish belonging to the Class of Actinopterygii, Order Pleuronectiformes and Family Soleidae. Its geographical distribution in the Mediterranean sea is fairly broad, covering the south and east of the Iberian Peninsula, the North of Africa and Middle East until the coast of Turkey. From a commercial perspective Solea senegalensis has acquired in recent years, a key role in aquacolture industry of the Iberian Peninsula. The Senegalese sole is also acquiring an important relevance in chronobiological studies as the number of published works focused on the sole circadian system has increased in the last few years. The molecular mechanisms underlying sole circadian rhythms has also been explored recently, both in adults and developing sole. Moreover, the consideration of the Pleuronectiformes Order as one of the most evolved teleost groups make the Senegalese sole a species of high interest under a comparative and phylogenetic point of view. All these facts have reinforced the election of Senegalese sole as model species for the present study. The animals were kept under 12L:12D photoperiod conditions and divided into three experimental groups depending on the feeding time: fed at midlight (ML), middark (MD) or random (RND) times. Throughout the experiment, the existence of a daily activity rhythm and it synchronization to the light-dark and feeding cycles was checked. To this end locomotor activity was registred by means of two infrared photocells placed in pvc tube 10 cm below the water surface (upper photocell) and the other one was located 10 cm above the bottom of the tank (bottom photocell). The photocell were connected to a computer so that every time a fish interrupted the infrared light beam, it produced an output signal that was recorded. The number of light beam interruptions was stored every 10 minutes by specialized software for data acquisition.
Resumo:
The mechanical action of the heart is made possible in response to electrical events that involve the cardiac cells, a property that classifies the heart tissue between the excitable tissues. At the cellular level, the electrical event is the signal that triggers the mechanical contraction, inducing a transient increase in intracellular calcium which, in turn, carries the message of contraction to the contractile proteins of the cell. The primary goal of my project was to implement in CUDA (Compute Unified Device Architecture, an hardware architecture for parallel processing created by NVIDIA) a tissue model of the rabbit sinoatrial node to evaluate the heterogeneity of its structure and how that variability influences the behavior of the cells. In particular, each cell has an intrinsic discharge frequency, thus different from that of every other cell of the tissue and it is interesting to study the process of synchronization of the cells and look at the value of the last discharge frequency if they synchronized.
Resumo:
In the present study, we have tried to expand our knowledge about the endocrine mechanisms that regulate feeding and growth in cultured fish, which could be relevant for the improvement of fish farming conditions and feeding strategies. In order to reach this goal, we have investigated some orexigenic hormones, Neuropeptide Y (NPY) and the paralogues of Agouti-related protein, (AgRP1, AgRP2) in Solea senegalensis, an important species for Mediterranean aquaculture. We focused on hormones synchronization to different feeding regimes (diurnal vs nocturnal and random feeding) and photoperiod (light-dark cycle vs constant darkness). Therefore, the achieved results could also be relevant from a chronobiological perspective. Solea senegalensis specimen were reared in two different photoperiods, i.e.LD Light-Dark conditions as well as in DD conditions (constant darkness) along with different feeding regimes (fed at ML, Med and RND times), so to determine if mRNA expression of orexigenic hormones (NPY, AgRP1 and AgRP2) are entrained by feeding time and/or photoperiod. Our results show an independence of npy mRNA expression from the feeding time and suggest an endogenous control of npy expression in telencephalon of sole, while in optice tectum, npy expression could be entrained by the light-dark cycle. Our results on Senegalese sole AgRP1 and AgRP2 showed the same pattern of expression, indicating that expression of AgRPs is related to photoperiod in optic tectum, instead to feeding time. However the involvement of AgRP1 and AgRP2 in feeding behaviour should not be discarded in sole, as further research will be carried out with specimens maintained under different fasting conditions. our results reinforce the role of the telencephalon as the main neural area involved in the neuroendocrine control of food intake in fish, where endogenous NPY rhythms have been found, while diencephalon statistical variations weren’t observed suggesting that this brain area could be less involved in the neuroendocrine control of food intake in fish than previously thought.