Search results for "informatica"
showing 10 items of 1003 documents
Assessment of Cardiorespiratory Interactions During Spontaneous and Controlled Breathing: Non-linear Model-free Analysis
2022
In this work, nonlinear model-free methods for bivariate time series analysis have been applied to study cardiorespiratory interactions. Specifically, entropy-based (i.e. Transfer Entropy and Cross Entropy) and Convergent Cross Mapping asymmetric coupling measures have been computed on heart rate and breathing time series extracted from electrocardiographic (ECG) and respiratory signals acquired on 19 young healthy subjects during an experimental protocol including spontaneous and controlled breathing conditions. Results evidence a bidirectional nature of cardiorespiratory interactions, and highlight clear similarities and differences among the three considered measures.
Transfer Entropy Analysis of Pulse Arrival Time - Heart Period Interactions during Physiological Stress
2022
Although Heart Period (HP) variability is the most widely used measure to assess cardiovascular oscillations, its evaluation combined with that of Pulse Arrival Time (PAT) variability may provide additional information about cardiac dynamics and cardiovascular interactions. In this study, we computed the transfer entropy from PAT to HP in 76 subjects monitored at rest and during orthostatic and mental stress using both a model-free (k- Nearest Neighbors) and a linear parametric estimator. Our results show how the information flow between these two variables depends on the physiological condition and how the nonlinear measure captures more information than the linear one during orthostatic s…
Feasibility of Ultra-short Term Complexity Analysis of Heart Rate Variability in Resting State and During Orthostatic Stress
2022
In this work, we study ultra-short term (UST) complexity of Heart Rate Variability (HRV) and its agreement with analysis of standard short-term (ST) HRV recordings obtained at rest and during orthostatic stress. Conditional Entropy (CE) measures have been computed using both a linear Gaussian approximation and a more accurate model-free approach based on nearest neighbors. The agreement between UST and ST indices has been compared via statistical tests and correlation analysis, suggesting the feasibility of exploiting faster algorithms and shorter time series for detecting changes in cardiovascular control during various states.
Assessment of Cardiorespiratory Interactions During Spontaneous and Controlled Breathing: Linear Parametric Analysis
2022
In this work, we perform a linear parametric analysis of cardiorespiratory interactions in bivariate time series of heart period (HP) and respiration (RESP) measured in 19 healthy subjects during spontaneous breathing and controlled breathing at varying breathing frequency. The analysis is carried out computing measures of the total and causal interaction between HP and RESP variability in both time and frequency domains (low- and high-frequency, LF and HF). Results highlight strong cardiorespiratory interactions in the time domain and within the HF band that are not affected by the paced breathing condition. Interactions in the LF band are weaker and prevalent along the direction from HP t…
On p21 tracking property in cancer cell unravelled bio-digitally in silico. Are apoptosis principles universal?
2010
Upon severe DNA damage, p21 acts in a dual mode; on the one hand, it inhibits the cyclin-CDK complex for arresting the G2/M transition and on the other hand, it indirectly becomes an apoptotic factor by activating--in sequence--the retinoblastoma protein, E2F1 and APAF1 expressions. But, in a cancer cells proliferation, the mechanisms of, and participants in, the apoptosis failure remain unclear. Since the p21/p53/Mdm2 proteins network normally involves a digital response in a cancer cell, through an original design of a cell signalling-protein simulator, we demonstrate, in silico, that apoptosis phase instability is fully reciprocated by p21 mRNA irregular dynamics which operates according…
Information flow in EEG source networks in epileptic children with focal seizure activity
2019
Scalp electroencephalographic (EEG) signals are influenced by several factors, including volume conduction and low spatial resolution, which can jeopardize the validity of brain connectivity analysis performed on the raw recordings. One possible solution is to identify, starting from scalp EEG signals, the underlying cortical source activations, and to apply connectivity metrics on the reconstructed source time series. In this work, the dynamics of information flow between cortical EEG signals obtained after source reconstruction were assessed in children suffering from focal epilepsy. In a group of 10 children with focal seizures, 5-second windows of the 19-channel EEG were obtained in the…
Quantifying High-Order Interactions in Cardiovascular and Cerebrovascular Networks
2022
We present a method to analyze the dynamics of physiological networks beyond the framework of pairwise interactions. Our method defines the so-called O-information rate (OIR) as a measure of the higher-order interaction among several physiological variables. The OIR measure is computed from the vector autoregressive representation of multiple time series, and is applied to the network formed by heart period, systolic and diastolic arterial pressure, respiration and cerebral blood flow variability series measured in healthy subjects at rest and after head-up tilt. Our results document that cardiovascular, cerebrovascular and respiratory interactions are highly redundant, and that redundancy …
Il cloud computing. Alla ricerca del diritto perduto nel web 3.0
2014
Il presente saggio intende mettere a fuoco il fenomeno del cloud computing, tentando di setacciare i frammenti normativi dispersi in un fiume di norme difficilmente componibili a sistema, al fine di ricostruire il quadro giuridico vigente in materia. La certezza e la conoscibilità del diritto sono esigenze che si fanno viepiù pressanti in un terreno, come quello in esame, ancora tutto da dissodare e l’ignoranza del quale può a ragione far temere, con la prozia Léonie nella Recherche, che « la journée ne se passera pas sans pluie ». Ed è alla luce dell’attuale incertezza che si spiega il singolare fenomeno per cui, secondo una ricerca del 2014, gran parte delle imprese italiane hanno familia…
Proprietà e proprietà europea nella Carta di Nizza
2013
IPRs in the third phase of the digital era. Cloud computing and the farewell to the property paradigm
Dalla carta al bit. Note metodologiche sull’edizione digitale di un cartulario medievale
2013
Il testo presenta il modello ipertestuale e sperimentale di edizione, ricerca e comunicazione storica incentrato su un cartulario vescovile, il Liber privilegiorum Sanctae Montis Regalis ecclesiae, nell’inedita tradizione quattrocentesca riportata dal codice Vat. Lat. 3880 attualmente conservato presso la Biblioteca Apostolica Vaticana. Il manoscritto e i documenti in esso trascritti sono stati codificati adottando la sintassi XML e uno schema di marcatura calibrato sulle caratteristiche specifiche della documentazione e sulle classiche esigenze e categorie di analisi critica della ricerca storica. Lo scopo del progetto è stato quello di evidenziare le possibili correlazioni tra testi e dat…