Search results for " autore"
showing 10 items of 124 documents
Investoru sentiments sociālajos medijos kā akciju cenu un tirdzniecības apjoma ietekmējošais faktors
2021
Pētījuma mērķis ir novērtēt investoru sentimentu sociālajos tīklos un pārliecināties vai investoru sentiments statistiski nozīmīgi ietekmē akciju cenu un tirdzniecības apjoma izmaiņu. Darbā aplūkots periods no 06.04.2016. līdz 29.04.2016, izmantojot augstas frekvences (stundas intervāla) datus par 36 “The Standard & Poor’s 500” indeksā iekļauto uzņēmumu akcijām. Sociālo mediju sentimenta aprēķināšanai ir izmantota vārdnīcu pieeja - konkrēti, R programmēšanas valodas bibliotēka “sentimentr”. Izmantojot vektoru autoregresijas (VAR) modeļus, iegūti statistiski nozīmīgi rezultāti, kas apliecina investora sentimenta ietekmi gan uz akciju ienesīgumu, gan uz tirdzniecības apjomu. Abos gadījumos ti…
Processi di autoregolazione dell'apprendimento e didattica orientativa. Learning Self-Regulation Processes and Guidance Didactics
2015
L'orientamento inteso come capacità di auto-dirigere se stessi nello studio e nel lavoro, in tutto il corso della propria vita, implica la necessità di sviluppare un complesso di competenze strategiche che risultano essere fondamentali per affrontare con successo il complesso quadro delle trasformazioni che investono il mondo del lavoro e della formazione. Il contributo affronta il rilievo delle capacità di autoregolazione nei processi di orientamento e presenta due metodologie (ALM e ADVP) utili a promuovere negli studenti della scuola secondaria l'autovalutazione di alcune competenze che sono alla base della capacità di dirigere se stessi nello studio e nel lavoro. Guidance, in the sense …
Assessing commodity price risks and terms of trade exposures in emerging and developing countries
2020
This paper provides novel evidence on commodity exposure (impacts of commodity price and terms of trade fluctuations) amongst 46 emerging and developing countries (EMDCs) in Africa, Asia and the Latin American and Caribbean (LAC) region. We focus on the exposures of six macroeconomic variables to the commodity prices and terms of trade, based on the real business cycle (RBC) theory. Our empirical results indicate that, overall, about 10% of the macroeconomic variation amongst the EMDCs is due to commodity market-related exposures. The Asian and LAC economies are especially sensitive to changes in commodity prices. The changes in the prices of world trade have an imminent impact on non-commo…
Information Decomposition in Multivariate Systems: Definitions, Implementation and Application to Cardiovascular Networks
2016
The continuously growing framework of information dynamics encompasses a set of tools, rooted in information theory and statistical physics, which allow to quantify different aspects of the statistical structure of multivariate processes reflecting the temporal dynamics of complex networks. Building on the most recent developments in this field, this work designs a complete approach to dissect the information carried by the target of a network of multiple interacting systems into the new information produced by the system, the information stored in the system, and the information transferred to it from the other systems; information storage and transfer are then further decomposed into amou…
A Framework to Assess the Information Dynamics of Source EEG Activity and Its Application to Epileptic Brain Networks
2020
This study introduces a framework for the information-theoretic analysis of brain functional connectivity performed at the level of electroencephalogram (EEG) sources. The framework combines the use of common spatial patterns to select the EEG components which maximize the variance between two experimental conditions, simultaneous implementation of vector autoregressive modeling (VAR) with independent component analysis to describe the joint source dynamics and their projection to the scalp, and computation of information dynamics measures (information storage, information transfer, statistically significant network links) from the source VAR parameters. The proposed framework was tested on…
Prevention and treatment of intracranial hypertension
2007
Intracranial pressure (ICP) is the pressure exerted by cranial contents on the dural envelope. It comprises the partial pressures of brain, blood and cerebrospinal fluid (CSF). Normal intracranial pressure is somewhere below 10 mmHg; it may increase as a result of traumatic brain injury, stroke, neoplasm, Reye's syndrome, hepatic coma, or other pathologies. When ICP increases above 20 mmHg it may damage neurons and jeopardize cerebral perfusion. If such a condition persists, treatment is indicated. Control of ICP requires measurement, which can only be performed invasively. Standard techniques include direct ventricular manometry or measurement in the parenchyma with electronic or fiberopti…
Simulating term structure of interest rates with arbitrary marginals
2011
Decision models under uncertainty rely their analysis on scenarios of the economic factors. A key economic factor is the term structure of interest rates (yields). Simulation models of the yield curve usually assume that the conjugate distribution of the interest rates is lognormal. Dynamic models, like vector auto-regression, implicitly postulate that the logarithm of the interest rates is normally distributed. Statistical analyses have, however, shown that stationary transformations (yield changes) of the interest rates are substantially leptokurtic, thus posing serious doubts on the reliability of the available models. We propose in this paper a VARTA model (Biller and Nelson, 2003) to s…
Has 1997 Asian crisis increased information flows between international markets
2003
Abstract The Asian crisis started on July 2, 1997 and caused turmoil in developed as well as emerging international stock markets. The objective of this paper is to analyse the effects of the crisis on the relationships of the Southeast Asian stock markets with the stock markets of three geographical areas (Europe, North America, and Latin America). We use the Morgan Stanley national and international indexes (MSCI) for two homogeneous and nonoverlapping time intervals. The econometric techniques used in this paper include the cointegration test, vector autoregression analysis, forecast error variance decomposition (FEVD), and impulse–response relationships. Our results show that: (i) there…
Characterization of the muscarinic receptor subtype(s) mediating contraction of the guinea-pig lung strip and inhibition of acetylcholine release in …
1997
1 The muscarinic receptor subtypes mediating contraction of the guinea-pig lung strip and inhibition of the release of acetylcholine from cholinergic vagus nerve endings in the guinea-pig trachea in vitro have previously been characterized as M-2-like, i.e. having antagonist affinity profiles that are qualitatively similar but quantitatively dissimilar compared to cardiac M-2 receptors. The present study sought to establish definitely the identity of these receptor subtypes by using the selective muscarinic receptor antagonist, tripitramine. Guinea-pig atria and guinea-pig trachea (postjunctional contractile response) were included for reference.2 It was found that tripitramine antagonized …
Effects of Fenoldopam on Intracranial Pressure and Hemodynamic Variables at Normal and Elevated Intracranial Pressure in Anesthetized Pigs
1994
Fenoldopam (FE), a dopamine DA1-receptor agonist, has been introduced for treatment of arterial hypertension and heart failure and for preservation of renal function. Vasodilators are generally assumed to affect all vascular beds including the cerebral circulation. We have evaluated effects of FE-induced (4 micrograms.kg-1.min-1) arterial hypotension on intracranial pressure (ICP) and intraocular pressure (IOP) under conditions of normal and increased intracranial elastance. ICP and IOP responses to hypertension were tested by infusion of angiotensin II (15 micrograms.kg-1.min-1), and the response to hypercapnia was tested by elimination and reintegration of soda lime canisters in the breat…