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Number of results: 76
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Abstract

In this paper the identification problem is considered for initial conditionsin a non-minimal state-space model that includes interpretable state variablesgenerated by non-stationary stochastic processes. In order to solve theidentification problem, structural restrictions are imposed on initial conditionsin a state-space model with redundant state variables. The correspondingrestricted maximum likelihood estimator of initial conditions is derived.The restricted estimator of initial conditions can be used in order tocompute uniquely identified realizations of interpretable latent variables. Theidentification problem is illustrated analytically using a simple structuraleconomic model.

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Authors and Affiliations

Victor Bystrov
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Abstract

The objective of the present deliberations was to systematise our knowledge of static visual variables used to create cartographic symbols, and also to analyse the possibility of their utilisation in the Augmented Reality (AR) applications on smartphone-type mobile devices. This was accomplished by combining the visual variables listed over the years by different researchers. Research approach was to determine the level of usefulness of particular characteristics of visual variables such as selective, associative, quantitative and order. An attempt was made to provide an overview of static visual variables and to describe the AR system which is a new paradigm of the user interface. Changing the approach to the presentation of point objects is caused by applying different perspective in the observation of objects (egocentric view) than it is done on traditional analogue maps (geocentric view). Presented topics will refer to the fast-developing field of cartography, namely mobile cartography. Particular emphasis will be put on smartphone-type mobile devices and their applicability in the process of designing cartographic symbols.
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Authors and Affiliations

Łukasz Halik
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Abstract

The study deals with stability and dynamic problems in bar structures using a probabilistic approach. Structural design parameters are defined as deterministic values and also as random variables, which are not correlated. The criterion of structural failure is expressed by the condition of non-exceeding the admissible load multiplier and condition of non-exceeding the admissible vertical displacement. The Hasofer-Lind index was used as a reliability measure. The primary research tool is the FORM method. In order to verify the correctness of the calculations Monte Carlo and Importance Sampling methods were used. The sensitivity of the reliability index to the random variables was defined. The limit state function is not an explicit function of random variables. This dependence was determined using a numerical procedure, e.g. the finite element methods. The paper aims to present the communication between the STAND reliability analysis program and the KRATA and MES3D external FE programs.

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Authors and Affiliations

A. Dudzik
U. Radoń
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Abstract

This paper presents some new results on exogeneity in models with latent variables. The concept of exogeneity is extended to the class of models with latent variables, in which a subset of parameters and latent variables is of interest. Exogeneity is discussed from the Bayesian point of view. We propose sufficient weak and strong exogeneity conditions in the vector error correction model (VECM) with stochastic volatility (SV) disturbances. Finally, an empirical illustration based on the VECM-SV model for the daily growth rates of two main official Polish exchange rates: USD/PLN and EUR/PLN, as well as EUR/USD from the international Forex market is presented. The exogeneity of the EUR/USD rate is examined. The strong exogeneity hypothesis of the EUR/USD rate is not rejected by the data.

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Authors and Affiliations

Anna Pajor
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Abstract

The paper presents the method of control of an induction squirrel-cage machine supplied by a voltage source converter. The presented idea is based on an innovative method of the voltage source converter control, consisting in direct joining of the motor control system with the voltage source rectifier control system. The combined control system gives good dc-bus voltage stabilization. In the applied control system the limits of the reference variables have been introduced. A correction of the estimated machine load torque is proposed. The new proposed solutions are confirmed by mathematical dependences, simulation and experimental results.

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Authors and Affiliations

Marcin Morawiec
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Abstract

This paper presents a low-cost and smart measurement system to acquire and analyze mechanical motion parameters. The measurement system integrates several measuring nodes that include one or more triaxial accelerometers, a temperature sensor, a data acquisition unit and a wireless communication unit. Particular attention was dedicated to measurement system accuracy and compensation of measurement errors caused by power supply voltage variations, by temperature variations and by accelerometers’ misalignments. Mathematical relationships for error compensation were derived and software routines for measurement system configuration, data acquisition, data processing, and self-testing purposes were developed. The paper includes several simulation and experimental results obtained from an assembled prototype based on a crank-piston mechanism

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Authors and Affiliations

J.M. Dias Pereira
Vítor Viegas
Octavian Postolache
Pedro Silva Girão
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Abstract

A similarity solution for conduction dominated solidification of a dilute binary isomorphous alloy has been developed. The effect solidification due to density change during phase transformation has been highlighted and investigated in detail. The governing equations for solid, liquid and mushy phase has been proposed, taking into account the effect of shrinkage or expansion due to density change during phase change. The thermo-physical properties (thermal conductivity and specific heat), equilibrium temperature and phase fraction are evaluated within the mushy zone using averaging technique. The effect of equilibrium and non-equilibrium solidification is investigated using Lever and Scheil’s rule models respectively. In addition, the effect of boundary and initial temperature on solidification behavior of the alloy is also addressed. It has been observed that the interface (liquidus and solidus) moves faster with increase in density ratio and decrease in boundary and initial temperature. No major changes in temperature distribution and interface position has been observed with variation partition coefficient and microscale behavior model (Lever rule and Scheil’s rule).
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Authors and Affiliations

A. Jakhar
1
ORCID: ORCID
L. Sharma
2
ORCID: ORCID
P. Rath
1
ORCID: ORCID
S. Kumar Mahapatra
1
ORCID: ORCID

  1. School of Mechanical Sciences, IIT Bhubaneswar, Bhubaneswar, 751012, India
  2. Chandigarh University, University Centre of Research & Development, Mohali-140413, Punjab
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Abstract

B a c k g r o u n d: Stress is a major risk factor for cardiovascular (CV) disease. We hypothesized that past strong experiences might modulate acute CV autonomic responses to an unexpected acoustic stimulus.
A i m: The study’s aim was to compare acute CV autonomic responses to acoustic stress between students with and without a past strong experience associated with the acoustic stimulus.
M a t e r i a l s and M e t h o d s: Twenty five healthy young volunteers — medical and non-medical students — were included in the study. CV hemodynamic parameters, heart rate (HR), and blood pressure (BP) variability were assessed for 10 min at rest and for 10 min after two different acoustic stimuli: a standard sound signal and a specific sound signal used during a practical anatomy exam (so-called “pins”).
R e s u l t s: Both sounds stimulated the autonomic nervous system. The “pins” signal caused a stronger increase in HR in medical students (69 ± 10 vs. 73 ± 13 bpm, p = 0.004) when compared to non-medical students (69 ± 6 vs. 70 ± 10, p = 0.695). Rises in diastolic BP, observed 15 seconds after sound stressors, were more pronounced after the “pins” sound than after the standard sound signal only in medical students (3.1% and 1.4% vs. 3% and 4.4%), which was also reflected by low-frequency diastolic BP variability (medical students: 6.2 ± 1.6 vs. 4.1 ± 0.8 ms2, p = 0.04; non-medical students: 6.0 ± 4.3 vs. 4.1 ± 2.6 ms2, p = 0.06).
C o n c l u s i o n s: The “pins” sound, which medical students remembered from their anatomy practical exam, provoked greater sympathetic activity in the medical student group than in their non-medical peers. Thus, past strong experiences modulate CV autonomic responses to acute acoustic stress.
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Bibliography

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5. Cheng T.H., Tsai C.G.: Female Listeners’ Autonomic Responses to Dramatic Shifts Between Loud and Soft Music/Sound Passages: A Study of Heavy Metal Songs. Front Psychol. 2016 Feb 17; 7: 182.
6. Walker E.D., Brammer A., Cherniack M.G., Laden F., Cavallari J.M.: Cardiovascular and stress responses to short-term noise exposures-A panel study in healthy males. Environ Res. 2016 Oct; 150: 391–397.
7. Berntson G.G., Bigger J.T. Jr, Eckberg D.L., et al.: Heart rate variability: origins, methods, and interpretive caveats. Psychophysiology. 1997; Nov; 34 (6): 623–648.
8. Cygankiewicz I., Zareba W.: Heart rate variability. Handb Clin Neurol. 2013; 117: 379–393.
9. Sacha J.: Interaction between heart rate and heart rate variability. Ann Noninvasive Electrocardiol. 2014 May; 19 (3): 207–216.
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Authors and Affiliations

Michał Jurczyk
1
Andrzej Boryczko
1
Agata Furgała
1
ORCID: ORCID
Adrian Poniatowski
1
Andrzej Surdacki
2
Krzysztof Gil
1

  1. Department of Pathophysiology, Jagiellonian University Medical College, Kraków, Poland
  2. Second Department of Cardiology, Institute of Cardiology, Jagiellonian University Medical College, Kraków, Poland
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Abstract

The objective of this study was an analysis of the thickness of a plasticized zone that appears after surface burnishing of machine parts with a non-deformable roller of a torus contour. A function defining the plasticized zone thickness depending on burnishing parameters was determined. M. T. Huber's hypothesis of plastic deformation was used in the solution. It was found that the thickness of the plasticized zone depends principally on the pressure force and yield point, and it is insignificantly dependent on the geometrical dimensions of the workpiece and burnishing roller.
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Authors and Affiliations

Józef Jezierski
Tomasz Mazur
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Abstract

The occurrence of gas confined in shales allows us to consider it as a component of the host rock. During drilling wells, the gas is released into the drilling fluid from finely ground gas-bearing rock particles. The amount of gas released can be determined on the basis of mud-gas logging; in addition, it is possible to determine the gas-content in shales expressed by the volume of gas released per mass unit of rock [m3/ton]. The gas content in the Ordovician and Silurian shales (Sasin formation and Jantar member respectively) in two selected wells in northern Poland was determined using this method. It has been found that clearly distinguishable, highly gas-bearing sections, which are separated by very poorly gas-bearing ones, can be determined in the well log. The increased gas content in shales can be observed in zones generally enriched in TOC. No direct correlation between TOC and gas-bearing capacity was found however, but the structure of TOC variability and the gas-bearing capacity described using variograms is identical. Correlations of the distinguished gas-bearing layers in the wells under consideration suggest a multi-lens or multi-layered reservoir model. The lack of natural boundaries in the shale gas reservoir means that they must be determined arbitrarily based on the assumed marginal gas-bearing capacity. In the case of several gas-bearing zones, numerous variants of interpretation are possible. In any case the low, best and high estimated resources may be evaluated, assigned to each borehole in the area with radii equal to the range of variogram of gas content in horizontal part of the well.

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Authors and Affiliations

Marek Nieć
ORCID: ORCID
Angelika Musiał
Justyna Auguścik
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Abstract

The suitability of several low-labor geostatistical procedures in the interpolation of highly positively skewed seismic data distributions was tested in the Baltic Basin. These procedures were a combination of various estimators of the model of spatial variation (theoretical variogram) and kriging techniques, together with the initial data transformation to normal distribution or lack thereof. This transformation consisted of logarithmization or normalization using the anamorphosis technique. Two variations of the theoretical variogram estimator were used: the commonly used classical Matheron estimator and the inverse covariance estimator (InvCov), which is robust with regard to non-ergodic data. It was expected that the latter would also be resistant to strongly skewed data distributions. The kriging techniques used included the commonly used ordinary kriging, simple kriging useful for standardized data and the non-linear median indicator kriging technique. It was confirmed that normalization (anamorphosis) is the most useful and less laborious geostatistical procedure of those suitable for such data, which results in a standardized normal distribution. The second, not obvious statement for highly skewed data distributions suggests that the non-ergodic inverted covariance (InvCov) estimator of variogram has an advantage over the Matheron’s estimator. It gives a better assessment of the C 0 (nugget effect) and C (sill) parameters of the spatial variability model. Such a conclusion can be drawn from the fact that the higher the estimation of the relative nugget effect L = C 0/(C 0 + C) using the InvCov estimator, the weaker the correlation between the kriging estimates and the observed values. The values of the coefficient L estimates obtained by using the Matheron’s estimator do not meet this expectation.
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Authors and Affiliations

Justyna Sowińska-Botor
1
Wojciech Mastej
1
ORCID: ORCID
Tomasz Maćkowski
1
ORCID: ORCID

  1. AGH University of Science and Technology, Faculty of Geology, Geophysics and Environmental Protection, Kraków, Poland
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Abstract

The article presents the results of research aimed at determining the catchment areas that pose a risk of nitrogen pollution of the waters of the Mała Panew river. The research was carried out in 13 permanent monitoring points located on the Mała Panew. The location of the points ensured the representativeness of the water quality results for parts of the catchment area with a homogeneous type of land use. Concentrations of nitrate-nitrogen (NO3-N) and total nitrogen (TN) were determined in the samples taken. The content of (NO3-N) in the third quarter of the year and its relation to the value obtained for the first year quarter may be an indicator of the impact of agricultural activities on the quality of water in streams. In the case of agricultural catchments, the lowest concentrations of NO3-N and TN occur in the third quarter of the year and are significantly lower than in the first quarter of the year. The demonstrated seasonal variability of nitrate nitrogen concentrations in agriculturally used areas may be used to determine the type of pressure not allowing to achieve good water status in the surface water body. It was shown that the highest unit increments occurred in areas with a high proportion of forest.
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Bibliography

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Authors and Affiliations

Aleksandra Steinhoff-Wrześniewska
1
Maria Strzelczyk
1
ORCID: ORCID
Marek Helis
1
ORCID: ORCID
Anna Paszkiewicz-Jasińska
1
ORCID: ORCID
Łukasz Gruss
2
Krzysztof Pulikowski
2
Witold Skorulski
3

  1. Institute of Technology and Life Science – National Research Institute
  2. Institute of Environmental Engineering, Wroclaw University of Environmental and Life Sciences
  3. ART Strefa Witold Skorulski
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Abstract

Stem canker and black scurf of potato (Solanum tuberosum L.) caused by Rhizoctonia solani Kühn are important and epidemic diseases in potato-growing regions worldwide, including Iran. In this study, 120 isolates were retrieved from infected stem canker from six potato- growing regions in Iran (Isfahan, Ardebil, Fars, Hamedan, Kurdestan and Kerman). Out of these, 30 isolates were selected as representatives for genetic and virulence analysis. The isolates were analyzed by one sequence analyzes of the ITS-rDNA region, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), as well as virulence studies. Based on sequence analysis of the ITS-rDNA region, all 30 isolates were assigned to the anastomosis group (AG) and all were assigned to AG-3 PT. Cluster analysis using the unweighted pair group method with the arithmetic averages (UPGMA) method for both RAPD and ISSR markers revealed that they were divided into three main groups, with no correlation to geographical regions of the isolates. Pathogenicity tests showed that all isolates were pathogenic on potato cv. Agria; however, virulence variability was observed among the isolates. The grouping based on RAPD analysis and virulence variability was not correlated.

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Authors and Affiliations

Mehdi Nasr Esfahani
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Abstract

From the regulatory point of view a strong link between an animal model and human pharmacodynamics of biological drugs is very important to qualify the model as “relevant”. Consistent changes in cell population between human physiology and animal model gain value of this model which then can be pharmacodynamically “relevant” from the regulatory point of view. Consequently, the aim of this study was to determine how similar to human observations is the effect of selected biological drugs on blood cells in a pig model. The study was to carry out a comparative analysis of the variability of selected biochemical and hematological parameters of the blood after administration of five different human therapeutic monoclonal antibodies (mAbs) after a single subcutaneous (SC) dose in breeding pigs. The tested drugs were siltuximab (Syl- vant®), omalizumab (Xolair®), infliximab (Inflectra®), pembrolizumab (Keytruda®), and vedoli- zumab (Entyvio®) given in a single 1 mg/kg SC injection. Each of the tested drugs exerted a sig- nificant effect on at least two of the tested parameters three weeks after the administration. Siltuximab significantly influenced 9 of the analyzed parameters. Vedolizumab significantly influenced 8 of the analyzed parameters. Infliximab had the lowest impact of all the tested drugs, as it significantly influenced only two of the analyzed parameters. The study has proved that the impact of mAbs on the analyzed parameters can be significantly extended over time. This requires the monitoring of hematological parameters in the pig model even many weeks af- ter administration of a drug in a relatively small dose.

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Authors and Affiliations

T. Grabowski
A. Burmańczuk
A. Miazek
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Abstract

The article presents the results of the second part of an eye-tracking study conducted on Polish secondary school students working with a textbook for learning English. 20 dyslexic and 20 non- dyslexic school students worked with two sets of materials that had different graphic layouts but the same content. Their eye movements were recorded. The analysed data show that the arrangement of the material and images on the textbook page influence both the way the students (especially dyslexic ones) work with the book and their results.

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Authors and Affiliations

Agnieszka Andrychowicz-Trojanowska
Sambor Grucza
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Abstract

APNB (alkaline phenolic no bake), widely known as Alphaset is one of the major sand binder systems used in foundries to make molds and cores without application of heat or gas. This is a two part system comprising of a phenol-formaldehyde resin in alkaline medium as binder and range of esters of dibasic acids and/or polyhydric alcohols as hardeners.

Resin performance varies depending upon formulations. Major variables in formulations are mole ratio of phenol: formaldehyde, total alkali content, ratio of two alkalis (NaOH & KOH) and molecular weight of polymers i.e. chain length.

In present work, one mole ratio of phenol & formaldehyde has been chosen to prepare 8 resins with following details.

Table 1.

Physical and chemical properties of eight (fresh) resins, A to H

Properties A B C D E F G H
Viscosity at 30°C (mPs-a) 56 47 66 51 39 44 49 52
Na (%) 5.94 3.21 5.94 3.21 nil 2.73 nil 2.73
K (%) nil 3.31 nil 3.31 7.18 3.87 7.18 3.87
Molecular weight Low Low High High Low Low High High
Gel Time at 121°C, mt-sec 27-0 29-30 24-0 30-0 30-0 27-30 26-30 26-0
Moisture (%) 52.43 52.42 53.01 53.75 55.58 54.12 51.61 54.03
Non-volatile Content (%) 48.74 47.25 49.10 49.35 47.63 47.32 48.06 48.29
Specific Gravity 1.182 1.177 1.183 1.180 1.172 1.184 1.178 1.188
Free Phenol (%) 0.47 0.42 0.44 0.43 0.37 0.27 0.41 0.20

Properties of these 8 formulations have been studied for strength and viscosity over a period of 12 weeks in 4 week interval.

Attempt has been made to develop a simple test for simulating hot & retained strength of molds in laboratory. Process followed for chasing hot and retained strength is described under clause 2.

With more and more understanding of the chemistry of alphaset system in last three & half decades it has been possible to identify role of variables contributing towards specific properties vis a vis developing tailor made formulations to fulfill requirements of individual foundries right from mold making to de coring.

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Authors and Affiliations

D.K. Ghosh
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Abstract

The aim of the study was to determine biologic variations of the main parameters in cows in early lactation and to compare intra-individual variations of parameters in cows and other species. 50 cows were included in the experiment. Blood samples were taken at the moment of calving, then on 1st, 7th, 14th and 28th day after calving. CVi had the following values: 1.9-5% for MCV, MCH, MCHC, GLU, TProt, ALB, UREA, Ca, P and Mg; 5.1-10% for RBC, Hgb, Hct, WBC, NEU, LYM, BHB, ALT, CHOL, TGC and >10% for PLT, NEFA, TBil, AST and GGT. For RBC, Hgb, Hct, MCV, MCH subject-based reference values or the reference change value should be used. For all other parameters except AST, population-based reference intervals should be used with caution. For LYM, NEU, PLT, GLU, TProt, ALB, CHOL and TGC index of individuality was close to 0.6 which means that subject-based reference values can be much more adequate to use then population-based reference intervals. For AST population-based intervals should be used. There is little effect of parity (increase CVi with parity) and no effect of milk production. CVi values obtained in cows in early lactation are specific because they deviate from the CVi values of other animal species and human. Calculated RCVs varied from 5.5% for MCHC to 41% for AST. High individuality index for many metabolic parameters opens possibility for development of model for longitudinal monitoring of metabolic status of individual animals during lactation. That requires further research.
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Authors and Affiliations

V. Kovačević
1
M.R. Cincović
1
B. Belić
1
R. Đoković
2
I. Lakić
1
M. Radinović
1
A. Potkonjak
1

  1. Department of Veterinary Medicine, Faculty of Agriculture, University of Novi Sad, Trg D.Obradovića 8, 21000 Novi Sad, Serbia
  2. Faculty of Agronomy, University of Kragujevac, Ul. Cara Dušana 34, 32000 Čačak, Serbia
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Abstract

The symbolic analysis of heart rate variability (biomarker of cardiac autonomic homeostasis) is a nonlinear and effective tool for pattern extraction and classification in a series analysis, which implies the transformation of an original time series into symbols, represented by numbers. Autonomic heart rate control is influenced by different factors, and better indicators of heart rate variability are found in healthy young individuals than in older and sicker individuals. The aim of this study was to compare the indicators of heart rate variability among healthy dogs in different age groups and in health status using the nonlinear method of symbolic analysis to evaluate the diagnostic accuracy of this method for the risk of death in dogs. An increase in cardiac sympathetic modulation was observed in puppies and dogs at risk of death, which was evidenced by a marked increase of 0 V% (without variation – associated with sympathetic modulation) and a decrease in patterns of 2 V% (two variations – associated with parasympathetic modulation), while the opposite was observed in young adult dogs with increased parasympathetic modulation. Elderly dogs showed a gradual decrease in parasympathetic activity, which tended to worsen with loss of health. It is concluded that the variables of symbolic analysis may be useful to evaluate autonomic modulation in dogs and assist in the differentiation between health states, advanced disease and death throughout the life cycle and have been shown to be indices with high specificity, sensitivity and diagnostic accuracy to help identify dogs at risk of death.
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Authors and Affiliations

L. Martinello
1
F.G. Romão
1
M.F. Godoy
2
L.H.A. Machado
1
M.H. Tsunemi
3
M.L.G. Lourenço
1

  1. São Paulo State University (Unesp), School of Veterinary Medicine and Animal Science
  2. Department of Cardiology and Cardiovascular Surgery – São José do Rio Preto Medical School (FAMERP)
  3. São Paulo State University (Unesp), Institute of Biosciences, Botucatu, São Paulo, Brazil
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Abstract

Upper Miocene (~6 Ma) sediments from a north-south transect of Ocean Drilling Program Holes 848B, 849B, 850B, 851B across the equator in the Eastern Pacific Ocean record an episode of unusual skeletal variability associated with the silicoflagellate Bachmannocena diodon subsp. nodosa (Bukry) Bukry, 1987. Skeletons in this plexus persisted for between 55,000 and 75,000 years and include an arch across a 2-sided basal ring, a highly unusual morphology for the genus. Groups of skeletal morphotypes were common within the plexus episode, and occur in a systematic sequence that is consistent between sites. As a result of this study, silicoflagellates previously placed in the genus Neonaviculopsis Locker and Martini, 1986 are now considered part of the Bachmannocena diodon subsp. nodosa plexus.
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Authors and Affiliations

Adrianna Szaruga
1
Kevin McCartney
2
Jakub Witkowski
1

  1. Institute of Marine and Environmental Sciences, University of Szczecin, Mickiewicza 16a, 70-383 Szczecin, Poland
  2. Department of Environmental Studies and Sustainability, University of Maine at Presque Isle, Presque Isle, ME 04769 USA
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Abstract

The author defends the thesis that language is an attribute of a nation and as such it is offi cially protected by the international legal system irrespective of the number of its speakers; thus, there is no such phenomenon as a “little language”. Linguistic minorities speak their mother languages or some dialectal variants of those languages

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Authors and Affiliations

Zuzanna Topolińska
ORCID: ORCID
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Abstract

The dynamic changes in selected heavy metal concentrations were analyzed in two ombrotrophic peat bogs from southern Poland: Puścizna Mala (PK) and Puścizna Krauszowska (PM). The highest contents of Pb and Zn occur at the top of profiles examined: 115.36 mg/kg (PM1), 90.61 mg/kg (PM2), 182.40 mg/kg (PK1), 121.68 mg/kg (PK2) and 127.43 mg/kg (PM1), 89.73 mg/kg (PM2), 170 mg/kg (PK1), 130.4 mg/kg (PK2), respectively. Concentrations of copper are similar to those of local soils varying from 9.4 to 12.8 mg/kg. Cadmium strongly varies with depth, which indicates distinct mobility of this element. Two peaks of elevated Fe concentrations are observed at the top and bottom of the Puścizna Mala profile, while the maximum in Puścizna Krauszowska was at the top of the peat bog. The Ti content distinctly varies with depth and correlates with the ash content (R 2 = 0.91-0.99). The strongest and positive correlation is observed between Zn-Pb and Ti-Pb contents. The significant differences of metal concentrations are noted between the profiles, which is probably connected with a rate of peat accumulation and plant composition of the profiles investigated, as well as with their disturbance by human activity.

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Authors and Affiliations

Barbara Fiałkiewicz-Kozieł
Beata Smieja-Król
Bernard Palowski
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Abstract

Zooplankton was investigated at fixed site in 24 hours in Kongsfjorden, a glacial fjord situated on the west coast of Spitsbergen (Svalbard) (79°N, 12°E), in order to unveil the level of diurnal variability in community composition and abundance. Parallel to zooplankton study water temperature and salinity were measured while information on local tides and winds was obtained from external sources. Observed changes did not exceed the range of variability regarded intrinsic, resulting from the nature of plankton. Because of this low variability we are of the opinion that the data presented can be regarded a valid measure of the natural heterogeneity of zooplankton communities in hydrologically dynamic Arctic coastal waters in summer. The observed changes in zooplankton were primarily induced by the complex dynamics of the fjord’s water masses. In spite of importance of tidal forcing, the variability in zooplankton did not demonstrate similar temporal fluctuations due to modification of the water movement by other irregular forces (local wind). Also, we have not found any indication of diel vertical migration in coastal water in the Arctic under the condition of midnight sun.

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Authors and Affiliations

Wojciech Walkusz
Sławomir Kwaśniewski
Katarzyna Dmoch
Agnieszka Beszczyńska-Möller
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Abstract

News might trigger jump arrivals in financial time series. The “bad” news and “good” news seem to have distinct impact. In the research, a double exponential jump distribution is applied to model downward and upward jumps. Bayesian double exponential jump-diffusion model is proposed. Theorems stated in the paper enable estimation of the model’s parameters, detection of jumps and analysis of jump frequency. The methodology, founded upon the idea of latent variables, is illustrated with simulated data.

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Authors and Affiliations

Maciej Kostrzewski

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