Extreme value theory in emerging markets

This paper investigates the performance of extreme value theory (EVT) with the daily stock index returns of four different emerging markets. The research covers the sample representing the Serbian (BELEXline), Croatian (CROBEX), Slovenian (SBI20), and Hungarian (BUX) stock indexes using the data from January 2006 - September 2009. In the paper a performance test was carried out for the success of application of the extreme value theory in estimating and forecasting of the tails of daily return distribution of the analyzed stock indexes. Therefore the main goal is to determine whether EVT adequately estimates and forecasts the tails (2.5% and 5% at the tail) of daily stock index return distribution in the emerging markets of Serbia, Croatia, Slovenia, and Hungary. The applied methodology during the research includes analysis, synthesis and statistical/mathematical methods. Research results according to estimated Generalized Pareto Distribution (GPD) parameters indicate the necessity of applying market risk estimation methods, i.e. extreme value theory (EVT) in the framework of a broader analysis of investment processes in emerging markets

In Vivo and In Vitro Virulence Analysis of Four Genetically Distinct Toxoplasma gondii Lineage III Isolates

Toxoplasma gondii archetypes II and III are mildly virulent, yet virulence of variant strains is largely unknown. While lineage II dominates in humans in Europe, lineage III strains are present in various intermediate hosts. In Serbia, lineage III represents 24% of the population structure and occurs most frequently in domestic animals, implying a significant presence in the human food web. In this study, the virulence of four genetically distinct lineage III variants was assessed in vivo and in vitro. In vivo, two strains were shown to be intermediately virulent and two mildly virulent, with cumulative mortalities of 69.4%, 38.8%, 10.7%, and 6.8%, respectively. The strain with the highest mortality has previously been isolated in Europe and may be endemic; the strain with the lowest mortality matches ToxoDB#54, while the remaining two represent novel genotypes. Identical alleles were detected at ROP5, ROP16, ROP18, and GRA15. A set of in vitro analyses revealed proliferation and plaque formation as virulence factors. Higher levels of expression of ENO2 in intermediately virulent strains point to enhanced metabolism as the underlying mechanism. The results suggest that metabolic attenuation, and possibly stage conversion, may be delayed in virulent strains

Structural Properties of Some C2-Symmetric Schiff Bases and Stereoselectivity in Cyclopropanation of Styrene by Their Cu(I) Complexes

C2-symmetric Schiff bases derived from ñ-camphor and R-fenchone (1-6) were prepared, their configurational and conformational features determined by ID- and 2D-NMR spectra and supported by MM2 calculations. Their Cu(I) complexes prepared in situ were examined in cyclopropanation of styrene and low to medium e.e.\u27s (2-32%) were obtained. Correlation of the structure of E,E-1 and Z,Z-6 with enantioselectivity of their Cu(I) complexes revealed restricting steric requirements in the former, possessing gem dimethyl group in the proximity of the chiral centre, near to the coordination sphere of alkene and carbene, as the probable origin of its higher enantioselectivity

Evidence for host genetic regulation of altered lipid metabolism in experimental toxoplasmosis supported with gene data mining results

Toxoplasma gondii is one of the most successful parasites on Earth, infecting a wide array of mammals including one third of the global human population. The obligate intracellular protozoon is not capable of synthesizing cholesterol (Chl), and thus depends on uptake of host Chl for its own development. To explore the genetic regulation of previously observed lipid metabolism alterations during acute murine T. gondii infection, we here assessed total Chl and its fractions in serum and selected tissues at the pathophysiological and molecular level, and integrated the observed gene expression of selected molecules relevant for Chl metabolism, including its biosynthetic and export KEGG pathways, with the results of published transcriptomes obtained in similar murine models of T. gondii infection. The serum lipid status as well as the transcript levels of relevant genes in the brain and the liver were assessed in experimental models of acute and chronic toxoplasmosis in wild-type mice. The results showed that acute infection was associated with a decrease in Chl content in both the liver and periphery (brain, peripheral lymphocytes), and a decrease in Chl reverse transport. In contrast, in chronic infection, a return to normal levels of Chl metabolism has been noted. These changes corresponded to the brain and liver gene expression results as well as to data obtained via mining. We propose that the observed changes in Chl metabolism are part of the host defense response. Further insight into the lipid metabolism in T. gondii infection may provide novel targets for therapeutic agents

The influence of holiday effect on the rate of return of emerging markets: a case study of Slovenia, Croatia and Hungary

Taking into account the current trends and opportunities in the financial markets of developing countries, the subject of the research is to analyse, test and quantify the impact of the holiday effect on the daily return rates from investing activities for the observed financial markets of Slovenia, Croatia and Hungary. The aim of the research is to gain a concrete, empirically tested and quantified knowledge of the capabilities and effectiveness of autoregressive conditional heteroscedasticity (A.R.C.H.) and generalized autoregressive conditional heteroscedasticity (G.A.R.C.H.) models, in order to quantify the impact of the holiday effect on the rates of return from investing activities in the observed financial markets. The time period covered by the research is 2003–2016, where the length of the research time horizon makes possible model effectiveness testing in the periods before, during and after the global financial crisis. The methodology also includes S.I.C.–A.I.C. (Schwarz and Akaike) model selection criteria and a number of tests suitable for or adapted to the specific characteristics of financial markets in developing countries. The research results confirm the role and importance of the application of econometric models in order to quantify the risks of investing activities in the financial mar- kets of developing countries

Severe Acute Pancreatitis as a Part of Multiple Dysfunction Syndrome

Acute pancreatitis is a disease with various degrees of clinical manifestations. Mild and moderate severe acute pancreatitis is an illness characterized with chemical inflammation which, in general, passes without major complications. Clinical picture of severe acute pancreatitis other side is commonly complicated with functional deterioration of other organs, and frequently has characteristics of multiple organ dysfunction or failure syndrome with or without bacterial super infection. We studied 82 patients admitted to the intensive care unit with severe acute pancreatitis, 14 died. The mortality was in statistically significant correlation with the severity of clinical condition at admission assessed by APACHE II score, and higher Ranson’s and Glasgow criteria by admission. Adequate volume supplementation, on time, as well as percutaneous drainage of infected pancreas collection reduces a risk of pure outcome

Comparative evaluation of three commercial Toxoplasma-specific IgG antibody avidity tests and significance in different clinical settings

Determination of the avidity of specific IgG antibodies has become a generally accepted diagnostic aid for dating Toxoplasma infection. In this study, the Labsystems, VIDAS and EUROIMMUN Toxoplasma IgG avidity assays were compared on a series of 133 Toxoplasma IgG- and IgM-positive sera from symptomatic patients (n=28), from pregnant (n=43) and nonpregnant (n=26) women, and on 18 IgG-positive and IgM-negative sera from chronically infected patients. The results showed excellent concordance between the Labsystems and VIDAS tests in both the IgM-positive (r=0.82, kappa=0.771) and IgM-negative (kappa=0.609) sera, whilst the agreement of the EUROIMMUN assay with both the Labsystems and VIDAS tests in the IgM-positive sera was moderate (kappa=0.575 and kappa=0.525, respectively) and in the IgM-negative sera was poor (kappa=0.000). Analysis of the kinetics of the maturation of avidity in 13 patients in whom follow-up sera were available showed that, despite a general trend of maturation, in two patients the avidity did not become high during 6 and 11 months of follow-up. In view of the clinical setting, in the symptomatic patients, despite one case of complete discrepancy and five cases of partial discrepancy, the Labsystems and VIDAS tests were in almost perfect agreement (kappa=0.812), whilst the agreement in pregnant and non-pregnant women was substantial (kappa=0.754 and kappa=0.708, respectively). In conclusion, the Labsystems and VIDAS tests are equally reliable for the measurement of Toxoplasma IgG avidity; the choice of test should depend on the laboratory setup. The EUROIMMUN test may be an acceptable alternative in resource-limited settings, but should be used prudently

Epidemiology of Taenia solium infection in the Russian Federation in the last 20 years: a systematic review

Taenia solium is a zoonotic parasite that causes taeniasis and cysticercosis in humans (as final hosts) and cysticercosis in pigs (as intermediate hosts). The Russian Federation (RF) is traditionally considered as endemic for this zoonosis. However, the epidemiological data on T. solium infection have not been reviewed for the past 20 years, in which time dynamic economical and societal changes have occurred in the RF. The aim of this systematic review was to analyse the status of T. solium infection in RF in the 2000–2019 period. A literature search was conducted, which collected published articles, grey literature and official data on the epidemiology of T. solium taeniasis and cysticercosis in the RF published from 2000. From a total of 2021 articles and 24 official reports originally returned by the search, data were extracted from 12 full text articles and 11 official reports. Taenia solium taeniasis was continuously reported in the RF between 2000 and 2019, with a tenfold decrease in the incidence, from 0.2 per 100,000 population in 2000 to 0.023/100,000 in 2019. Also, the number of administrative units where taeniasis was detected continuously decreased. Cysticercosis in pigs had a declining trend after 2006. In conclusion, although decreasing, T. solium infection is still endemic in several regions and suspected to be endemic in most of the RF

Epidemiology of Toxoplasmosis in SERBIA: A Cross-Sectional Study on Blood Donors

Toxoplasmosis is a globally distributed parasitic zoonosis, affecting approximately one third of the human population. Epidemiological studies on toxoplasmosis conducted in Serbia so far have been focused on women of childbearing age, without a clear insight into the prevalence in the general population. We conducted a cross-sectional study in a representative sample of the healthy adult population consisting of 1095 blood donors of both genders to establish the prevalence and risk factors for Toxoplasma gondii infection. Data on the demographic and clinical characteristics of all study participants, as well as on their lifestyle habits, were collected by means of a questionnaire. The overall prevalence of infection was 20.5% (224/1095) and the avidity of the specific IgG antibodies detected was high in a vast majority of the seropositive donors (98.2%). Interestingly, the remaining 1.8% of the specific IgG positive samples were of borderline avidity (4/224), in complete absence of specific IgM. The multivariate logistic regression analysis showed that independent risk factors included age (from OR (95% CI) 1.9 (1.13–3.28) in the 30–39 age group, to 6.8 (3.27–14.24) in the age group of >60 years), suburban living (OR (95% CI) 2.2 (1.43–3.34)) and contact with soil (OR (95% CI) 1.4 (1.01–1.94)). This first large-scale study on toxoplasmosis in the general population in Serbia shows the lowest prevalence ever reported in this country. Moreover, the novel perspective on risk factors provides an updated basis for future prevention programs

Toxoplasma gondii Genotypes Circulating in Serbia—Insight into the Population Structure and Diversity of the Species in Southeastern Europe, a Region of Intercontinental Strain Exchange

In Europe, Toxoplasma gondii lineage II is dominant, and ToxoDB#1 the most frequently occurring genotype. The abundance of lineage III genotypes varies geographically and lineage I are rare, yet present in several regions of the continent. Data on the T. gondii population structure in southeastern Europe (SEE) are scarce, yet necessary to appreciate the diversity of the species in Europe. To help fill this gap, we genotyped 67 strains from nine species of intermediate hosts in Serbia by MnPCR-RFLP, determined the population structure, and identified the genotypes using ToxoDB. A neighbor-joining tree was also constructed from the isolates genotyped on nine loci. While 42% of the total genotype population consisted of ToxoDB#1 and ToxoDB#2, variant genotypes of both lineages comprised 46% of the population in wildlife and 28% in domestic animals and humans. One genotype of Africa 4 lineage was detected in a human sample. Interestingly, the findings include one lineage III variant and one II/III recombinant isolate with intercontinental distribution, which appear to be moderately related to South American genotypes. Based on these findings, SEE is a region of underappreciated T. gondii genetic diversity and possible strain exchange between Europe and Africa