Gábor Dávid Kiss

Transmission Dynamics and Final Epidemic Size of Ebola Virus Disease Outbreaks with Varying Interventions

The 2014 Ebola Virus Disease (EVD) outbreak in West Africa was the largest and longest ever reported since the first identification of this disease. We propose a compartmental model for EVD dynamics, including virus transmission in the community, at hospitals, and at funerals. Using time-dependent parameters, we incorporate the increasing intensity of intervention efforts. Fitting the system to the early phase of the 2014 West Africa Ebola outbreak, we estimate the basic reproduction number as 1.44. We derive a final size relation which allows us to forecast the total number of cases during the outbreak when effective interventions are in place. Our model predictions show that, as long as cases are reported in any country, intervention strategies cannot be dismissed. Since the main driver in the current slowdown of the epidemic is not the depletion of susceptibles, future waves of infection might be possible, if control measures or population behavior are relaxed.

Reliability of anthropometric parameters in the prediction of the visceral fat area among adult women.

Visceral fat accumulation is a risk factor for cardiometabolic diseases. Magnetic resonance imaging (MRI) and computed tomography (CT) provided the most accurate techniques of abdominal fat assessment, but these methods are very expensive. The aim of this study was to examine and compare the predictive ability of simple anthropometric parameters for visceral fat area (VFA) among adult women in different age and obesity status groups. The sample consisted of 133 adult women (aged 18-76 years). All subjects underwent anthropometric measurements. Body composition and VFA were determined with a multi-frequency bioimpedance analyzer (BIA). 16.9% of the younger women (age < 45) were obese with a body-mass index (BMI) > or = 30.0 kg/m2, and 23.2% of the older individuals (age > 45) had BMI > or = 30 kg/m2. After age and BMI adjustment, the best correlation was observed between VFA and waist circumference (WC) in younger women (R = 0.347, p = 0.002). In the case of the older women, the best correlation efficient values were for SAD (R = 0.560, p < 0.001) and hip circumference (R = 0.550, p < 0.001). The partial correlation coefficients were consistently higher for younger subjects with excessive fat accumulation (overweight & obese subgroup; individuals with WC > 80 cm) compared to women without obesity. Results of the multiple linear stepwise regression analyses showed the significance of age and BMI in prediction of VFA. In addition, hip circumference (HC) was one of the methods that best reflected VFA in older women independently from obesity status. Using single anthropometric parameters is not usually sufficient for predicting with good accuracy the VFA, but the convenient combination of these parameters could be a suitable way for the reliable prediction in Hungarian women.

Faces of Ageing and Fundamental Background of Pension Investments - In East Central Europe, Russia and Scandinavia

During the transition in East Central Europe, a number of criteria and schools of thought clashed over the creation of a market economy and the role of the state. The long-term demographic vulnerability of the region is also coupled with a crisis in the labor market tied to the transition. To deal with these problems, a series of pension reforms has attempted to improve the countrys demographic situation since the mid-1990s in addition to reducing the financial role of the state. Placing self-provision in the foreground, the state only assumes financial risk for the first pillar, thus, in making a regional comparison of pension systems, the economic background and the status of the countrys external equilibrium must be taken into account. This study compares potential Slovenian, Czech, Hungarian and Russian pension portfolios with Swedish, Danish and Finnish data - bearing in mind differences in the real economy.

Controlling Mackey–Glass chaos

The Mackey-Glass equation is the representative example of delay induced chaotic behavior. Here, we propose various control mechanisms so that otherwise erratic solutions are forced to converge to the positive equilibrium or to a periodic orbit oscillating around that equilibrium. We take advantage of some recent results of the delay differential literature, when a sufficiently large domain of the phase space has been shown to be attractive and invariant, where the system is governed by monotone delayed feedback and chaos is not possible due to some Poincaré-Bendixson type results. We systematically investigate what control mechanisms are suitable to drive the system into such a situation and prove that constant perturbation, proportional feedback control, Pyragas control, and state dependent delay control can all be efficient to control Mackey-Glass chaos with properly chosen control parameters.

The Impact of Financial Interdependence on the Czech, Hungarian and Polish Interbank, Stock and Currency Market

Contagions could be defined as a significant increase in market comovement after a shock to one country, and mostly explained by two theorems: strong cross border relationships between the economies or sudden shifts in market actor’s expectations and confidence. The first hypothesis of contagion was accepted on stock market but mostly rejected on interbank and currency market. The second hypothesis, that stock market contagions have the same orientation as trade was rejected. The analysis in this paper employed Dynamic Conditional Correlation GARCH analysis on logarithmic returns to evaluate deviation of market prices from fundamental values under extreme conditions on the selected interbank, stock and currency markets.

Várakozások és a monetáris politika - különös tekintettel a magyarországi gyakorlatra

A tanulmanyban bemutatjuk a varakozasok es a monetaris politika kozotti kapcsolat elmelet- es gazdasagtorteneti hatteret, majd megvizsgaljuk, hogy a monetaris rezsimek utobbi nehany evtizedben megfigyelhető valtozasai - kulonos tekintettel Magyarorszagon - mikent juttattak meghatarozo szerephez a varakozasok kezeleset. A tanulmany masodik feleben okonometriai modszerekkel elemezzuk a hazai monetaris politika kapcsolatat a varakozasokkal. Kimutatjuk, hogy a kamatpolitika az elmult 19 evben kepes volt befolyasolni a penzpiaci inflacios varakozasokat, a piac elfogadta a kamatdonteseket megalapozo inflacios előrejelzeseket, es beepitette varakozasaiba, tovabba az iranyado kamatlab valtozasaban megjelent az inflacios celtol valo elteres is, valamint a devizaarfolyam valtozasa. Osszessegeben elmondhato, hogy az időszak egesze soran a kamatlab valtozasa megfelelt a nemzetkozi szakirodalom szabalyainak. Journal of Economic Literature (JEL) kod: E42, E58, C32.

Long-Term Financial Stability in Russia

Reserve Fund, National Wealth Fund and the funded part of the pension system are acting as a puffer to smooth the impact of external shocks on Russian federal budget. Sensibility for external shocks is the result of raw material exporter role of the country; witch affects not only the balance of capital account, but the economic activity and indirectly the demographic balance too. Russia has to face with external turmoils in the future due to the structure of its economy, so the strategy of forming sovereign wealth funds and de facto monopoly in the second pillar is logical strategy to smooth external shocks. But market based management human life cycle means that market risks – and the flow of global liquidity – will influent not only the active years but inactive years too, while these risks were transferred from the state to the individual trough the introduction of multipillar pension system. Therefore the introduction of multi pillar system can not care the problems of ageing, but establish a stable demand for government bonds.

Analyses of Extreme Events on Emerging Capital Markets

This study deals with the statistical methods of contagion-effects on emerging capital markets. After fitting probability distribution on the empirical data, and cross-market correlation sensibility test were used on time series (2002-2009) of Hungarian, Polish Russian and US government bond, stock and currency markets to study their behavior under extreme and normal circumstances. The aim of this analysis is to identify the possible differences between emerging and developed capital markets to investigate the validity of economic axioms according to the relation of bond, stock and currency markets on the emerging markets.

Hungarian Banking System and MiFID - Results of Mystery Shopping Trips

Sale of funds units is regulated by Markets in Financial Instruments Directive in the European Economic Area to increase competition and consumer protection in investment services. Interaction between retail financial advisers and clients were studied by mystery shoppers. The sample included 41 frequented bank offices in the capital and other cities in March-April 2008 and 14 bank offices in the capital in February 2009. Measured level of financial services was fragmented, and was not acceptable according to MiFID standards. Details of investment funds were not clear for financial advisers in the sample, and they did not give the required attention for clients preferences.

Convergence and Contagion in Transitional Countries

During the transition time in East Central Europe, a number of schools of thoughts clashed over the creation of a market economy and the role of the state. This study compares Slovenian, Czech, Hungarian and Russian external balance and factors of external vulnerabilities with Swedish, Danish and Finnish data bearing in mind the differences in the real economy. The comparison takes into account the bounded rational market participants on complex, scale-free global capital markets, which resulted erratic convergence in this region.