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Search Results: 1 - 10 of 1915 matches for " Pietro Gottardo "
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Speed of Adjustment and Infraday/Intraday Volatility in the Italian Stock and Futures Markets  [PDF]
Pietro Gottardo
Modern Economy (ME) , 2011, DOI: 10.4236/me.2011.25082
Abstract: We estimate the speed of adjustment of prices to value changes in the Italian stock and futures markets using variances in different return intervals. The paper presents evidence that an assumption of linearity for the relationship volatility-time is untenable when intraday and infraday data are used jointly. Prices adjust to new information within three days, but the process is complex with evidence of overshooting and divergent movements in the smaller return intervals. Firms behave differently according to their inclusion or exclusion from the MIB30 index. The speed of adjustment is strongly related to firm-specific characteristics and the log of capitalization explains some of the cross-sectional variability in the adjustment coefficients for most of the return intervals.
The Fragmentation of Entrepreneurial Functionand the Role of External Control on Management Behavior  [PDF]
Pietro Gottardo, Anna Maria Moisello
iBusiness (IB) , 2011, DOI: 10.4236/ib.2011.34045
Abstract: Starting from the interpretation of corporate governance as the outcome of the fragmentation of entrepreneurial power and the related agency problem, the paper stresses the strict relationship between management control and risk management. This issue implies the need of effective internal and external controls, i.e. board implementation and supervision of a consistent control function and auditing, but the market and public regulatory authorities give the most important external control system. The paper focuses next on the role of the Codes of Conduct, the critical aspects of their effectiveness and other key issues in the governance of corporations highlighted by the last financial and economic crisis.
High and Low Leverage Choices: Some Evidence from Private Firms  [PDF]
Pietro Gottardo, Anna Maria Moisello
Modern Economy (ME) , 2016, DOI: 10.4236/me.2016.73030
Abstract: This paper studies the determinants of low and high leveraged financial structures analyzing a sample of 831 medium-large private firms, in the first and last quartile of the leverage distribution, using panel data and simultaneous equations procedures in the period 2001-2010. The empirical findings show that group membership and management factors influence financing decisions, and that internal capital markets, net working capital choices and product market position influence private firms’ capital structure choices, consistently with a pecking order perspective. This study provides evidence on medium large private firms, which are quite unexplored compared to small businesses and to the public counterpart, relying on the theoretical framework of the Pecking Order Theory integrated by product market competition and internal capital market theories.
Coronary sinus reentrant tachycardia after atrial fibrillation ablation: From bad to worse  [PDF]
Pietro Turco
World Journal of Cardiovascular Diseases (WJCD) , 2014, DOI: 10.4236/wjcd.2014.42006
Abstract: Herein we present a case of atrial tachycardia as a sequel of AF ablations. A 42-year-old man was admitted to our department because of a very symptomatic tachycardia. The patient, because of paroxysmal AF and typical atrial flutter, had been already submitted (three times) to ablation procedures in both left (pulmonary vein insulation) and right atria (cavo-tricuspidal isthmus). During the electrophysiological study, a huge and very fast atrial tachycardia was induced: 230 ms cycle length, 1/1 atrio-ventricular conduction with the ventricular rate of 260 bpm, complete left bundle branch block, and clinically recognized by the patient. Four minutes later, a 2/1 AV conduction without branch block permitted mapping and ablation. A high-density mapping around isthmus and coronary sinus (CS) was performed. The analysis of the chronological activation clearly showed a circuit propagation around the CS ostium with a very slow conduction in the anterior zone enlightened by the tight color progression, and counterclockwise activation of the right atrium lateral wall. In anterior zone of CS ostium diastolic fragmented electrograms were detected. After preventing his position localization, radiofrequency delivering (35 W) was effective to interrupt the arrhythmia in 3 seconds. Energy delivering was continued to anchor the lesion to the inferior vena cava. Confirmation of successful ablation was determined by unsuccessful attempts at reinduction of the arrhythmia, in basal state and during infusion of isoproterenol.
A Theoretical Overview of Bioresponse to Magnetic Fields on the Earth’s Surface  [PDF]
Pietro Volpe
International Journal of Geosciences (IJG) , 2014, DOI: 10.4236/ijg.2014.510097
Abstract: This survey points to the mechanisms of bioresponse caused by magnetic fields (MFs), paying attention to their action not only on ions, molecules and macromolecules, but also on cells, tissues and organisms. The significance of findings concerning the MF-dependence of cell proliferation, necrosis or apoptosis was judged by comparing the results obtained in a solenoid, where an MF can be added to the geomagnetic field (GMF), with those obtained in a magnetically shielded room, where the MFs can be attenuated or null. This comparative criterion was particularly appropriate when the differences detectable between the data provided by experimental samples and the data provided by control samples were rather small, as observed in estimating the MF-influence on total DNA replication, RNA transcription and polypeptide translation. The MF-induced inhibition of apoptosis was considered as a risk potentially leading to accumulation of cancer cells. The analysis also surveyed the MF-dependence of the interactions between host animal cells and infecting bacteria. In relation to studies on the origin and adaptation of life on the Earth, theoretical insights paving the way to elucidating the MF-interactions with biostructures and biosystems of different orders of organization evaluated the possible involvement of the so-called “biological windows”. Analogously to what is known for ionizing radiations, the efficiency of the applied MFs appeared to depend on the complexity of their biological targets.
The Outrageous Discourse of Psychoanalysis for Present-Day Academic Institutions  [PDF]
Pietro Barbetta
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.33021
Abstract: In the following essay I’m going to take a radical position concerning the tendency to eliminate psychoanalysis from the European Academic field and the failure of psychoanalysts and relational therapists to defend psychoanalysis from such aggression. My question is why in Italy—just to make a local example, which I am involved in—different kinds of psychoanalytical traditions are not able to defend themselves from this attack while in France, for another example, all the different branches of relational therapies have been able to unite in making a common effort to take a position for psychoanalysis. One of the main problems, in my opinion, concerns the constitutive marginality of psychoanalysis in relation to Academic Institutions. In my way of writing, I will use psychoanalysis, with “P” in capital character, when referred to Academia, and psychoanalysis, with no capital character, when referred to clinical practice.
The Unexpected Existence of Coding and Non-Coding Fragments along the Eukaryotic Gene  [PDF]
Pietro Volpe
Advances in Biological Chemistry (ABC) , 2015, DOI: 10.4236/abc.2015.52009
Abstract: The pathways leading to synthesis and post-synthetic modification of DNA employed methionine as donor of atoms: the carbon that came from its –CH3 served for DNA replication and repair either in bacteria or humans; its entire –CH3 served instead for building N6-methyladenine and 5-methylcytosine on bacterial DNA and 5-methylcytosine alone on human DNA. In humans, although a slight extra-S asymmetric methylation appeared de novo yielding on parental DNA 5’-m5CpC-3’/ 3’-GpG-5’, 5’-m5CpT-3’/3’-GpA-5’ and 5’-m5CpA-3’/3’-GpT-5’ monomethylated dinucleotide pairs, a heavy symmetric methylation involved in S semiconservatively newly made DNA to guarantee genetic maintenance of –CH3 in 5’-m5CpG-3’/3’-Gpm5C-5’ dimethylated dinucleotide pairs. In this framework, an inverse correlation was found between bulk genomic DNA methylation occurring in S and bulk polyA-containing pre-mRNA transcription taking place in G1 and G2. Thus, probes of 1 × 106 Daltons (constructed using sheared by sonication newly made methylated DNA filaments) revealed a modular organization in genes: after the hypermethylated promoter, they exhibited an alternation of unmethylated coding and methylated uncoding sequences. This encouraged the search for a language that genes regulated by methylation should have in common. An initial deciphering of restriction minimaps with hypomethylatable exons vs. hypermethylatable promoters and introns was improved when the bisulfite technique allowed a direct sequencing of m5C. In lymphocytes, where the transglutaminase gene is inactive, its promoter exhibited two fully methylated CpG-rich domains at 5’ and one fully unmethylated CpG-rich domain at 3’, including the site +1 and a 5’-UTR. At variance, in HUVEC cells, where the transglutaminase gene is active, in the first CpG-rich domain of promoter few doublets lost their –CH3. Such an inverse correlation suggested new hypotheses especially in connection with repair-modification: UV radiation would cause demethylation in given loci of a promoter by chance, whilst even a partial demethylation in this promoter would be able to resume a previously silent pre-mRNA transcription.
A new approach for epileptic seizure detection: sample entropy based feature extraction and extreme learning machine  [PDF]
Yuedong Song, Pietro Liò
Journal of Biomedical Science and Engineering (JBiSE) , 2010, DOI: 10.4236/jbise.2010.36078
Abstract: The electroencephalogram (EEG) signal plays a key role in the diagnosis of epilepsy. Substantial data is generated by the EEG recordings of ambulatory recording systems, and detection of epileptic activity requires a time-consuming analysis of the complete length of the EEG time series data by a neurology expert. A variety of automatic epilepsy detection systems have been developed during the last ten years. In this paper, we investigate the potential of a recently-proposed statistical measure parameter regarded as Sample Entropy (SampEn), as a method of feature extraction to the task of classifying three different kinds of EEG signals (normal, interictal and ictal) and detecting epileptic seizures. It is known that the value of the SampEn falls suddenly during an epileptic seizure and this fact is utilized in the proposed diagnosis system. Two different kinds of classification models, back-propagation neural network (BPNN) and the recently-developed extreme learning machine (ELM) are tested in this study. Results show that the proposed automatic epilepsy detection system which uses sample entropy (SampEn) as the only input feature, together with extreme learning machine (ELM) classification model, not only achieves high classification accuracy (95.67%) but also very fast speed.
Three-Dimensional Representation of Geochemical Data from a Multidimensional Compositional Space  [PDF]
Pietro Armienti, Placido Longo
International Journal of Geosciences (IJG) , 2011, DOI: 10.4236/ijg.2011.23025
Abstract: Systems described by a wide set of variables, like rock compositions, may be often modeled by a reduced set of components, like minerals, that can be represented in diagrams in two or three dimensions. This paper deals with an original algorithm that allows the representation of compositional data in tetrahedral diagrams, provided that they can be recast on the basis of four end members. The algorithm is based on the orthogonal projection of a given point belonging to Rn to the 3D-space through four Rn points representing the compositions of suitable end members. The algorithm is applied to the assessment of mass balance problems (in weight% or molar basis) as well as to the identification of the geochemical imprint revealed by isotope ratios in igneous rock suites. The fields of possible applications are by far wider, encompassing all problems of comprehensive data representation from a multidimensional space to a bi-dimensional plot.
Inter-Network Resource Sharing in IEEE 802.22 Networks  [PDF]
Carla Passiatore, Pietro Camarda
Communications and Network (CN) , 2012, DOI: 10.4236/cn.2012.42015
Abstract: IEEE 802.22 is the first worldwide standard for Cognitive Networks (CNs) that exploits unused spectrum of the television broadcast service. An IEEE 802.22 network is also called Wireless Regional Area Network (WRAN). An open issue in cognitive 802.22 networks is represented by the resource distribution among WRANs. In this paper a protocol for radio resource management for CNs in a multichannel environment is presented and analysed. In particular, the contribution of this work is a resource sharing method to schedule the WRAN access to the available channels in a community made by two o more coexisting WRANs. The method adapts to the continuous changes of the spectrum availability due to necessity of vacating a channel in case of the incumbent primary users. Moreover, the introduced allocation scheme allows to divide the available band in a proportional way to the cognitive user spectrum demands, taking into account the issue of spatial diversity, i.e. the case where the channel coverage area is not uniform. The effectiveness of the proposed multichannel scheme is proved through simulations. The results compared favorably with other methods already known in literature and show that the proposed algorithm optimize the spectral efficiency, keeping high fairness as demonstrated computing the Jain’s index.
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