65 research outputs found
On entropy of probability integral transformed time series
Abstract
The goal of this paper is to investigate the changes of entropy estimates when the amplitude distribution of the time series is equalized using the probability integral transformation. The data we analyzed were with known properties—pseudo-random signals with known distributions, mutually coupled using statistical or deterministic methods that include generators of statistically dependent distributions, linear and non-linear transforms, and deterministic chaos. The signal pairs were coupled using a correlation coefficient ranging from zero to one. The dependence of the signal samples is achieved by moving average filter and non-linear equations. The applied coupling methods are checked using statistical tests for correlation. The changes in signal regularity are checked by a multifractal spectrum. The probability integral transformation is then applied to cardiovascular time series—systolic blood pressure and pulse interval—acquired from the laboratory animals and represented the results of entropy estimations. We derived an expression for the reference value of entropy in the probability integral transformed signals. We also experimentally evaluated the reliability of entropy estimates concerning the matching probabilities
Prisustvo Listerija vrsta u uzorcima riba, proizvoda od ribe i morskih plodova
Listeria monocytogenes is a bacterium that is pathogenic for man and for most animal species. Listeriosis is a generalized infection that starts after ingestion of the causative agent L. monocytogenes (Finlay, 2001). Food that is not properly thermically processed, long storage of such food, food that is produced in inadequate hygienic food plants, as well as cooked-cooled ready to eat food (RTE) is the ideal medium for listeria multiplication. High risk food originated from fish, fish products and sea products comprised of: molluscs (fresh of frozen shellfish, crustaceans shelled or not), fresh fish (ready to eat without cooking), fish products packed with brine (NaCl lt 6%), (salted, marinated, fermented, cold smoked and fish in brine), thermically treated fish and crustacean products (pasteurization, cooking, hot smoking, including pre-cooking and panning). In this research, fish samples, fish products and sea products from Serbian markets were examinated such as: fresh fish (cooled), frozen food (fish and sea products - cuttlefish, squid, octopus, shellfish, crustaceans and shrimps), panned products; smoked fish, salted fish, thermally treated fish and fish products, semi-canned fish and canned fish. Microbiological testing has been performed according to internationally prescribed standards ISO 11290-1 (1996) 'Microbiology of food and animal feed stuffs - Horizontal method for the detection and enumeration of Listeria monocytogenes'. There were 470 samples from fish products and sea products. Presence of Listeria spp was registered in 58 samples (12.34%). Listeria monocytogenes was found in 1.92% samples (9 isolates), which makes 15.52% of the total Listeria that were isolated from the tested food. Other isolated Listeria belong to the following species: L. innocua (8.51%), L.welshimeri (1.28%), L.welshimeri/innocua (0.21%), L. grayi (0.21%) and L. seeligeri (0.21%). Exceptional viability of Listeria monocytogenes in the food tested was documented, also (freezing temperature - 18oC, five months).Listeria monocytogenes je bakterija patogena za ljude i veliki broj životinjskih vrsta. Listerioza predstavlja generalizovanu infekciju koja nastaje nakon oralne ingestije uzročnog agensa L. monocytogenes (Finlay, 2001). Navedena bakterija se najbolje razvija u namirnicama koje nisu adekvatno termički obrađene; koje su dugo skladištene; koje su proizvedene na mestu na kojem principi higijenskog rukovanja hranom nisu sprovođeni; kuvano-hladnoj hrani spremnoj za jelo (ready to eat food - RTE) U visoko rizične namirnice počev od vrsta ribe, proizvoda od ribe i plodova mora ubrajaju se: mekušci (sveže i zamrznute školjke, rakovi u ljušturama, ili očišćeni), sveža riba (koja se konzumira bez termičke obrade), riblji proizvodi u vodenom rastvoru soli (NaCl%), (soljena, marinirana, fermentisana, hladno dimljena i riba u sopstvenom soku), srednje termički obrađeni riblji proizvodi i rakovi (pasterizacija, kuvanje, toplo dimljenje, uključujući i pred-kuvanje i panirani proizvodi). Kao materijal za ispitivanje korišćeni su uzorci riba, proizvoda od riba i morski plodovi: sveža riba (u rashlađenom stanju), zamrznute namirnice (riba i morski plodovi - lignje, sipe, hobotnice, školjke, rakovi i škampi), panirani proizvodi, dimljena riba, usoljena riba, termički obrađena riba i proizvodi od ribe, polukonzerve i konzerve od ribe. Mikrobiološko ispitivanje je rađeno prema propisanoj metodi po Međunarodnom standardu ISO 11290-1 (1996) 'Microbiology of food and animal feeding stuffs - Horizontal method for the detection and enumeration of Listeria monocytogenes'. Ukupno je ispitano 470 uzoraka ribe, proizvoda od ribe i morskih plodova. Prisustvo Listeria vrsta utvrđeno je u 58 uzoraka (12,34%). Listeria monocytogenes je utvrđena kod 1,92% pregledanih uzoraka (9 izolata) i čini 15,52% od svih vrsta iz roda Listeria koje su izolovane iz navedenih namirnica. Ostale vrste listerija koje su izolovane pripadale su: L. innocua (8,51%), L. welshimeri (1,28%), L. welshimeri/innocua (0,21%), L. grayi (0,21%) i L. seeligeri (0,21%). Ustanovljena je izuzetna sposobnost preživljavanja pri niskim temperaturama vrste Listeria monocytogenes u namirnicama koje su čuvane pri temperaturi od -18oC tokom 5 meseci
Supplementary data for article: Mišić, D.; Šiler, B.; Gašić, U.; Avramov, S.; Živković, S.; Živković, J. N.; Milutinović, M.; Tešić, Ž. Simultaneous UHPLC/DAD/(+/-)HESI-MS/MS Analysis of Phenolic Acids and Nepetalactones in Methanol Extracts of Nepeta Species: A Possible Application in Chemotaxonomic Studies. Phytochemical Analysis 2015, 26 (1), 72–85. https://doi.org/10.1002/pca.2538
Supporting information for: [https://doi.org/10.1002/pca.2538]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1663
A geometric network model of intrinsic grey-matter connectivity of the human brain
Network science provides a general framework for analysing the large-scale brain networks that naturally arise from modern neuroimaging studies, and a key goal in theoretical neuro- science is to understand the extent to which these neural architectures influence the dynamical processes they sustain. To date, brain network modelling has largely been conducted at the macroscale level (i.e. white-matter tracts), despite growing evidence of the role that local grey matter architecture plays in a variety of brain disorders. Here, we present a new model of intrinsic grey matter connectivity of the human connectome. Importantly, the new model incorporates detailed information on cortical geometry to construct ‘shortcuts’ through the thickness of the cortex, thus enabling spatially distant brain regions, as measured along the cortical surface, to communicate. Our study indicates that structures based on human brain surface information differ significantly, both in terms of their topological network characteristics and activity propagation properties, when compared against a variety of alternative geometries and generative algorithms. In particular, this might help explain histological patterns of grey matter connectivity, highlighting that observed connection distances may have arisen to maximise information processing ability, and that such gains are consistent with (and enhanced by) the presence of short-cut connections
Supplementary data for article: Mišić, D.; Šiler, B.; Gašić, U.; Avramov, S.; Živković, S.; Živković, J. N.; Milutinović, M.; Tešić, Ž. Simultaneous UHPLC/DAD/(+/-)HESI-MS/MS Analysis of Phenolic Acids and Nepetalactones in Methanol Extracts of Nepeta Species: A Possible Application in Chemotaxonomic Studies. Phytochemical Analysis 2015, 26 (1), 72–85. https://doi.org/10.1002/pca.2538
Supporting information for: [https://doi.org/10.1002/pca.2538]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1663
Extracting Message Inter-Departure Time Distributions from the Human Electroencephalogram
The complex connectivity of the cerebral cortex is a topic of much study, yet the link between structure and function is still unclear. The processing capacity and throughput of information at individual brain regions remains an open question and one that could potentially bridge these two aspects of neural organization. The rate at which information is emitted from different nodes in the network and how this output process changes under different external conditions are general questions that are not unique to neuroscience, but are of interest in multiple classes of telecommunication networks. In the present study we show how some of these questions may be addressed using tools from telecommunications research. An important system statistic for modeling and performance evaluation of distributed communication systems is the time between successive departures of units of information at each node in the network. We describe a method to extract and fully characterize the distribution of such inter-departure times from the resting-state electroencephalogram (EEG). We show that inter-departure times are well fitted by the two-parameter Gamma distribution. Moreover, they are not spatially or neurophysiologically trivial and instead are regionally specific and sensitive to the presence of sensory input. In both the eyes-closed and eyes-open conditions, inter-departure time distributions were more dispersed over posterior parietal channels, close to regions which are known to have the most dense structural connectivity. The biggest differences between the two conditions were observed at occipital sites, where inter-departure times were significantly more variable in the eyes-open condition. Together, these results suggest that message departure times are indicative of network traffic and capture a novel facet of neural activity
Team Dynamics Theory: Nomological network among cohesion, team mental models, coordination, and collective efficacy
I put forth a theoretical framework, namely Team Dynamics Theory (TDT), to address the need for a parsimonious yet integrated, explanatory and systemic view of team dynamics. In TDT, I integrate team processes and outputs and explain their relationships within a systemic view of team dynamics. Specifically, I propose a generative nomological network linking cohesion, team mental models, coordination, collective efficacy, and team outcomes. From this nomological conceptualization, I illustrate how myriad alternative models can be derived to account for variance in different working teams, each comprised of unique members, and embedded in singular contexts. I outline TDT’s applied implications for team development, the enhancement of team functioning, and the profiling of team resilience. I conclude by discussing how TDT’s ontological and nomological propositions can be tested through various theoretical inquiries, methodological approaches, and intervention-based studies
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