Search results for "Roca"

Procarioti dalle mille risorse: nuove scoperte sui metabolismi batterici che utilizzano la luce

2013

I batteri fototrofi costituiscono un ampio ed eterogeneo gruppo di procarioti ampiamente distribuiti nel plancton marino ed i loro processi basati sulla luce sostengono e controllano il flusso di energia negli oceani. Recenti scoperte di nuovi batteri includono almeno tre modalità di fotosintesi: la fotosintesi aerobica ossigenica (tipica dei cianobatteri e simile a quella condotta dalle piante), la fotosintesi anaerobica anossigenica e la fotosintesi aerobica anossigenica (entrambe esclusive dei procarioti). Altri importanti processi basati sulla luce utilizzano le rodopsine, contribuendo così al metabolismo energetico cellulare. La fotosintesi ossigenica “pura” sembra più l’eccezione che …

Task-focused behaviour and literacy development: a reciprocal relationship

2009

University of Jyva¨skyla¨The purpose of this study was twofold: (a) to examine the effect of task-focusedbehaviour on reading fluency, spelling and comprehension; and (b) to examine therole of the different literacy skills in subsequent task-focused behaviour. Twohundred and seven Finnish-speaking children were followed from preschool untiltheir fourth year at school and were tested for reading fluency, spelling and readingcomprehension. The teachers also rated the children’s task-focused behaviour. Theresults showed that task-focused behaviour was a significant predictor of laterreading comprehension and spelling skills. However, all three literacy skillspredicted subsequent task-focused beha…

A fourier-based algorithm for micro-calcification enhancement in mammographic images

2008

Breast cancer is the most widespread cancer in women in the world; it manifests mostly in two forms: microcalcifications and massive lesions. These two forms differ in density, size, shape and number. Consequently, there are two different kinds of mammographic CAD algorithms: those for microcalcifications detection, and those for massive lesions detection. The microcalcifications detection is a hard task, since they are quite small and often poorly contrasted against the background, especially in images affected by digitization noise. In a CAD system the ROI Hunter plays an important role, because missed microcalcifications at this level are definitely lost. For this reason, highlighting me…

Bioelectric model of atrial fibrillation: Applicability of blind source separation techniques for atrial activity estimation in atrial fibrillation e…

2003

In this contribution, we present the theoretical justification that give support to the suitability of blind signal separation (BSS) techniques for the estimation of the atrial activity (AA) present in ECGs of persistent atrial fibrillation (AF). The application of BSS methods to this problem needs the fulfillment of several conditions regarding AA, ventricular activity (VA) and the fashion in which both activities arise on the body surface, that will be justified along the paper. To empirically validate the model, an ICA method is applied to 10 real 12-lead recordings of AF. The identification of AA is put forward based on kurtosis and spectral analysis. The kurtosis value of the estimated…

Recognition of Cardiac Arrhythmia by Means of Beat Clustering on ECG-Holter Recordings

2012

The follow-up of some cardiac diseases may be achieved by ECG-holter record analysis. A heartbeat clustering method can be used to reduce the usually high computational cost of such Holter analysis. This study describes a method aimed at cardiac arrhythmia recognition based on this approach, by means of unsupervised inspection of morphologically similar heartbeat groups. Singular Value Decomposition (SVD) is used as the feature selection method since the complexity increases exponentially with the number of features. A modification of the k-means algorithm was developed for centroid computation, taking into account heartbeat length changes. Experimental set consisted of ECG records from the…

Miniature wireless photoplethysmography devices: integration in garments and test measurements

2012

Wireless PPG devices were developed and embedded in everyday clothes (bandage, scarf, cycling glove and wrist strap) to monitor cardiovascular state of free-moving persons. The corresponding software for measurements also has been developed and tested in laboratory. Real-time measurements of PPG signals were taken in parallel with a professional ECG reference device, and high correlation was demonstrated.

A second-degree atrioventricular block with double escape rhythm secondary to paroxysmal vagal hypertonia.

2017

Electrocardiographic Indices of Left Ventricular Hypertrophy and Repolarization Phase Share the Same Genetic Influences: A Twin Study

2009

Background: Both left ventricular hypertrophy (LVH) and repolarization phase (RP) are known to be attributable to genetic influences, but less is known whether they share same genetic influences. The aim of this study was to investigate to what extent individual differences in electrocardiographic (ECG) LVH and RP are explained by genetic and environmental influences and whether these influences are shared between these two traits. Methods: Resting ECG recordings were obtained from 186 monozygotic and 203 dizygotic female twin individuals, aged 63 to 76 years. Latent factors, called LVH and RP, were formed to condense the information obtained from LVH indices (Cornell voltage and Cornell pr…

Why does C-reactive protein increase in non-ST elevation acute coronary syndromes?

2003

Abstract Introduction: C-reactive protein is an important prognostic indicator for early risk stratification in patients with an acute coronary syndrome. The mechanisms underlying the elevation of C-reactive protein in these patients have not been fully understood. We studied the factors related to the increase of this acute-phase reactant. Methods and Results: Within a single-centre registry, 419 consecutive patients admitted for a non-ST elevation acute coronary syndrome were studied. Serum high sensitivity C-reactive protein was measured late (median 3 days) after admission. Clinical, electrocardiographic, biochemical and angiographic variables were recorded. In the multivariate analysis…

Pancreatic islets from non-heart beating donor pig: Two-layer preservation method in an in vitro porcine model

2011

Purpose Pancreata from non-heart beating donors could represent an unlimited source of islets if their cell viability can be efficiently preserved during the time necessary to process the organs by the use of a better solution of preservation compared to the classic University of Wisconsin solution. The aim of this study was to determine whether it is possible to obtain functioning “alive islets” from non-heart-beating donors by comparing, on a porcine model, the classic “UW ice-store” method with a two-layer cold storage method (TLM) using oxygenated Perfluorocarbons (PFC) and UW. Methods Whole pancreata were harvested from 20 NHBDs female pigs with similar characteristics and preserved fo…