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Number of results: 18
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Abstract

The literature investigates the relation between savings and interest rate mainly for household sector, but in recent decades households ceased to be the main source of savings in the economy. We try to identify how the savings of different sectors respond to the interest rate change using the SVAR methodology. We focus on Poland and generalize the results for other European economies. We find that although the household savings rate tends to rise after an increase of interest rate, the corporate savings simultaneously fall, inducing a negative conditional correlation between them. The responses of savings rate of general government and foreign savings are diverse (although the former usually declines after an interest rate increase) and does not seem to be related to factors like the membership in the currency union or the level of public debt. We also check the existence of the ‘crowding-out’ effects and conclude it only applies in the case of government savings crowding out household savings.
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Abstract

Forecasting yield curves with regime switches is important in academia and financial industry. As the number of interest rate maturities increases, it poses difficulties in estimating parameters due to the curse of dimensionality. To deal with such a feature, factor models have been developed. However, the existing approaches are restrictive and largely based on the stationarity assumption of the factors. This inaccuracy creates non-ignorable financial risks, especially when the market is volatile. In this paper, a new methodology is proposed to adaptively forecast yield curves. Specifically, functional principal component analysis (FPCA) is used to extract factors capable of representing the features of yield curves. The local AR(1) model with time-dependent parameters is used to forecast each factor. Simulation and empirical studies reveal the superiority of this method over its natural competitor, the dynamic Nelson-Siegel (DNS) model. For the yield curves of the U.S. and China, the adaptive method provides more accurate 6- and 12-month ahead forecasts.
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Abstract

The swap spread is defined as the difference between the fixed rate of an interest rate swap and the yield of the treasury with the same maturity. The swap spread is usually interpreted as the effective proxy of bank liquidity and the credit spread indicator. The interpretation is very similar to the LIBOR-OIS spread and in the context of Polish interbank market – WIBOR-OIS. However, WIBOR-OIS is less reliable during the crisis of confidence because of lack of interbank operation with the maturity longer than 1 month. Swap spreads base on two liquid instruments, thus they are free of this defect. The main goal of this paper is to assess how Polish swap spreads and their conditional variance reacted to important events connected with the subprime crisis and crisis of confidence in the Polish interbank market.
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Abstract

This study examines whether the lowering interest-rate environment in CEE countries since the early 2000’s increased bank risk-taking behaviour. We employ 6,979 annual observations from the Bankscope database over the period 1997‒2011 and find a positive relationship between bank risk-taking, measured by risk assets, and interest rates. On the contrary, there is a negative relationsh ipbetween non-performing loans and interest rates. These results are robust across a number of different specifications that account,inter alia, for the potential endogeneity of interest rates and/or the dynamics of bank risk. Moreover, we provide evidence that these findings are mainly driven by the banking sector of the Russian Federation rather than that of the rest CEE countries.
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Abstract

Changes in the size and the age structure of a population have a great impact on an economy, especially on national savings and capital flows. Poland’s population, although still relatively young when compared to other developed countries, is expected to experience accelerated ageing and decline in forthcoming decades. In this paper, we assess the effects of these processes for Polish economy. Using an open-economy OLG model with demographic shocks and a variable retirement age, we simulate dynamics of real interest rates, main macro aggregates as well as net foreign assets to GDP. We show that rapid ageing will reduce the interest rate gap between Poland and the developed countries by 1.3-2 p.p. We also document a strong positive relationship between interest rates and the retirement age and find that the decline in the interest rate in Poland is primarily driven by the surviving probability shock
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Abstract

This study attempts to evaluate the field performance of various mining equipment used at the development galleries of coal mines. These are hand-held and jumbo rock drills, and a roadheader used in mechanical excavation. For this purpose, the penetration rates of rock drills were monitored and measured in the field. The physical, mechanical, and drillability properties were determined through the collected samples in order to understand the complex interactions between the rock and bit/pick. The abrasive mineral content was also analyzed with XRD analysis to examine the wear on the cutting/drilling tools. Besides, the specific energy of the equipment was calculated relying on the operational parameters. A comparison of the monthly advance and production rates of the drilling rigs and roadheader was made. The relations among operating power, specific energy, and design of buttons/picks were investigated. It has been found that the average advance and production rates of the mining equipment are consistent with the penetration rate. The results verified that the roadheader used in mechanical excavation and the jumbo drill used in drilling and blasting technique are the machines maximizing the advance and production rates.
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Abstract

Several conclusions and recommendations concerning sediment trap geometry, the technique of their deployment and interpretation of measurements results are described in this paper. Only cylindrical sediment traps are able to cope with the diverse and dynamic environment of glaciated fjords. The relation between different trap parameters shows the optimal proportion of cylinder diameter as being between 6 and 10 cm and ratio length/diameter not less than 7/1. During the peak of the melting season in Kongsfjorden (Spitsbergen) the rate of sedimentation of total matter reaches over 900 g m–2 d–1 and the velocity of brackish water current can reach 80 cm s–1 on the surface. Owing to the high productivity of Arctic fiords and large concentration of suspended mineral matter it is possible to collect of large samples in a short time, therefore prevention of sediment traps by swimmers is not necessary.
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Abstract

Luminescence dating is based mainly on the dosimetric properties of quartz and feldspar. These minerals are among the most popular found on Earth, resulting in the possibility of using luminescence methods in practically any environment. Currently, quartz remains the best recognized mineral in terms of dosimetric properties, particularly with regards to results obtained for quartz grains, which are regarded as being the most reliable in luminescence dating. Supporters of luminescence methods are constantly growing, however, these groups do not always have sufficient knowledge to avoid even the most basic of issues that may be encountered overall – from the process of sampling through to the awareness of what a single luminescence result represents. The present paper provides an overview of several practical aspects of luminescence dating such as correct sampling procedures and all necessary information regarding the calculation of the dose rate and equivalent dose with particular reference to potential problems that occur when the age of the sample is being determined. All these aspects are crucial for obtaining a reliable dating result, on the other hand, they remain a potential source of uncertainty.
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Abstract

Thermoregulation is fully developed in 5 day old Wilson's storm petrels Oceanites oceanicus (Kuhl). Resting metabolic rate (RMR) and body temperature (Tb) of unattended 1- and 3-day old chicks continuously decrease at ambient temperature (Ta) of 5°C. After being heated the chicks return to normothermia. Ability to survive temporal deep hypothermia seems to be an adaptation to absence of parents and low temperatures in the nest during first days of life. After snow storm, during two days of starvation, chick RMR decreases by 40% at Ta of 0°C, but chick Tb is stable. This suggest decrease of thermal conductance (Ct). Fall of Ct may suggest beginning of hypohermia.
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Abstract

Twelve glaciers, representing various types, were investigated between 2000 and 2005, in a region adjacent to the northern reaches of Billefjorden, central Spitsbergen ( Svalbard ). On the basis of measurements taken using reference points, DGPS and GPS systems, analyses of aerial photographs and satellite images, geomorphological indicators and archival data their rates of deglaciation following the “Little Ice Age” (LIA) maximum were calculated variously on centennial, decadal and annual time scales. As most Svalbard glaciers have debris-covered snouts, a clean ice margin was measured in the absence of debris-free ice front. The retreat rates for both types of ice fronts were very similar. All studied glaciers have been retreating since the termination of the Little Ice Age at the end of 19th century. The fastest retreat rate was observed in the case of the Nordenskiöldbreen tidewater glacier (mean average linear retreat rate 35 m a-1). For land-terminating glaciers the rates were in range of 5 to 15 m a-1. Presumably owing to climate warming, most of the glacier retreat rates have increased several fold in recent decades. The secondary factors influencing the retreat rates have been identified as: water depth at the grounding line in the case of tidewater glaciers, surging history, altitude, shape and aspect of glacier margin, and bedrock relief. The retreat rates are similar to glaciers from other parts of Spitsbergen . Analyses of available data on glacier retreat rates in Svalbard have allowed us to distinguish four major types: very dynamic, surging tidewater glaciers with post-LIA retreat rates of between 100 and 220 m a-1, other tidewater glaciers receding of a rate of 15 to 70 m a-1, land terminating valley polythermal glaciers with an average retreat of 10 to 20 m a-1 and small, usually cold, glaciers with the retreat rates below 10 m a-1.
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Abstract

Plant responses to glyphosate applied at different doses were examined for one glyphosate resistant (R) and one glyphosate susceptible (S) population of Conyza albida and C. bonarienis. Growth rates and development stages of five R C. albida and three R C. bonarienis populations were also compared with those of their respective S counterparts to investigate the possible impact of the glyphosate resistance trait on their fitness. The GR50 values for C. albida R (3.94−5.22 kg a.i. · ha−1) and S (0.24−0.31 kg a.i. · ha−1) populations were higher than those of C. bonariensis R (0.60−1.51 kg a.i. · ha−1) and S (0.10−0.13 kg a.i. · ha−1). The growth rate (slope b) of one R C. albida population was lower than the respective S and other R populations, while growth rates of most R and S C. bonariensis populations were similar. Some R populations showed inconsistent differences in some development stages when compared to those of the S ones, which cannot be attributed to the glyphosate resistance trait.
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Abstract

Biological parameters of the larval parasitoid Cephalonomia tarsalis (Ashmead) (Hymenoptera : Bethylidae) and its host the saw-toothed beetle Oryzapehilus surinamensis (L.) (Coleoptera : Silvanidae) were studied in the laboratory. The duration of the immature period, survival during development, as well as adult longevity and the number of progeny of both insects were recorded. Our data were used for the estimation of several demographic parameters and life table construction of both the host and the parasitoid. The wasp managed to complete its development (egg – adult) in 19.8 days at 25oC, whereas the adult female lived for 24.3 days. The host O. surinamensis demonstrated a longer developmental period (30.5 days) and adult female longevity (103.0 days). Female wasps laid an average of 66.4 eggs throughout their lifetime whereas their beetle hosts laid five times more eggs (313.9). Life table parameters of C. tarsalis were estimated for the first time. The intrinsic rate of natural increase (rm) was 0.124 which was almost double that of its host (0.056). Our results are discussed on the basis of evaluating and improving the performance of C. tarsalis as a biocontrol agent against O. surinamensis in storage facilities.
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Abstract

Because of the value of time, investors are interested in obtaining economic benefits rather early and at a highest return. But some investing opportunities, e.g. mineral projects, require from an investor to freeze their capital for several years. In exchange for this, they expect adequate remuneration for waiting, uncertainty and possible opportunities lost. This compensation is reflected in the level of interest rate they demand. Commonly used approach of project evaluation – the discounted cash flow analysis – uses this interest rate to determine present value of future cash flows. Mining investors should worry about project’s cash flows with greater assiduousness – especially about those arising in first years of the project lifetime. Having regard to the mining industry, this technique views a mineral deposit as complete production project where the base sources of uncertainty are future levels of economic-financial and technical parameters. Some of them are more risky than others – this paper tries to split apart and weigh their importance by the example of Polish hard coal projects at the feasibility study. The work has been performed with the sensitivity analysis of the internal rate of return. Calculations were made using the ‘bare bones’ assumption (on all the equity basis, constant money, after tax, flat price and constant operating costs), which creates a good reference and starting point for comparing other investment alternatives and for future investigations. The first part introduces with the discounting issue; in the following sections the paper presents data and methods used for spinning off risk components from the feasibility-stage discount rate and, in the end, some recommendations are presented.
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Abstract

The Silurian Pelplin Formation is a part of a thick, mud-prone distal fill of the Caledonian foredeep, which stretches along the western margin of the East European Craton. The Pelplin Formation consists of organic carbon- rich mudstones that have recently been the target of intensive investigations, as they represent a potential source of shale gas. The Pelplin mudstones host numerous calcite concretions containing authigenic pyrite and barite. Mineralogical and petrographic examination (XRD, optical microscopy, cathodoluminoscopy, SEM-EDS) and stable isotope analyses (δ13Corg, δ13C and δ18O of carbonates, δ34S and δ18O of barite) were carried out in order to understand the diagenetic conditions that led to precipitation of this carbonate-sulfide-sulfate paragenesis and to see if the concretions can enhance the understanding of sedimentary settings in the Baltic and Lublin basins during the Silurian. Barite formed during early diagenesis before and during the concretionary growth due to a deceleration of sedimentation during increased primary productivity. The main stages of concretionary growth took place in yet uncompacted sediments shortly after their deposition in the sulfate reduction zone. This precompactional cementation led to preferential preservation of original sedimentary structures, faunal assemblages and early- diagenetic barite, which have been mostly lost in the surrounding mudstones during burial. These components allowed for the reconstruction of important paleoenvironmental conditions in the Baltic and Lublin basins, such as depth, proximity to the detrital orogenic source and marine primary productivity. Investigation of the concretions also enabled estimation of the magnitude of mechanical compaction of the mudstones and calculation of original sedimentation rates. Moreover, it showed that biogenic methane was produced at an early-diagenetic stage, whereas thermogenic hydrocarbons migrated through the Pelplin Formation during deep burial.
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Abstract

Alcohol is a recognized teratogen that affects various aspects of fetal development. Tissue that is particularly susceptible to its teratogenicity is neuronal tissue. The effect of prenatal alcohol exposure (PAE) on the central nervous system has been extensively studied, yet the knowledge on the influence of PAE on the autonomic nervous system is scarce. The purpose of this article is to review the current state of knowledge about the impact of PAE on the autonomic nervous system. Studies conducted on the PAE animal model have shown that prenatal alcohol exposure is associated with significant alterations in the autonomic nervous system, but the mechanisms and consequences are not yet clearly defined. It was established that PAE causes decreased heart rate variability (HRV) in fetal cardiotocography. Several studies have revealed that later, in infancy and childhood, reduced parasympathetic activity with or without compensating sympathetic activity is observed. This may result in behavioral and attention disorders, as well as an increased predisposition to sudden infant death syndrome. Both animal and human studies indicate that the relationship between PAE and autonomic dysfunction exists, however large, well-designed, prospective studies are needed to confirm the causal relationship and characterize the nature of the observed changes.
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Abstract

I n t r o d u c t i o n: Stress is an ubiquitous phenomenon in the modern world and one of the major risk factors for cardiovascular disease. Th e aim of our study was to evaluate the effect of various acute stress stimuli on autonomic nervous system (ANS) activity, assessed on the basis of heart rate (HRV) and blood pressure (BPV) variability analysis. Ma t e r i a l s a n d M e t h o d s: The study included 15 healthy volunteers: 9 women, 6 men aged 20– 30 years (23.3 ± 1.8). ANS activity was assessed by HRV and BPV measurement using Task Force Monitor 3040 (CNSystems, Austria). ECG registration and Blood Pressure (BP) measurement was done 10 minutes at rest, 10 minutes aft er the stress stimulus (sound signal, acoustic startle, frequency 1100 Hz, duration 0.5 sec, at the intensity 95 dB) and 10 minutes aft er the cold pressor test. The cold pressor test (CPT) was done by placing the person’s hand by wrist in ice water (0–4°C) for 120 s. R e s u l t s: Every kind of stress stimulation (acoustic startle; the CPT) caused changes of HRV indicator values. The time domain HRV analysis parameters (pNN50, RMSSD) decreased aft er acoustic stress and the CPT, but were signifi cantly lower after the CPT. In frequency domain HRV analysis, significant differences were observed only aft er the CPT: (LF-RRI 921.23 ms2 vs. 700.09 ms2; p = 0.009 and HF-RRI 820.75 ms2 vs. 659.52 ms2; p = 0.002). The decrease of LF-RRI and HF-RRI value aft er the CPT was significantly higher than after the acoustic startle (LF-RRI 34% vs. 0.4%, p = 0.022; HF-RRI 19.7% vs. 7% ms2, p = 0.011). The decreased value of the LF and HF components of HRV analysis are indicative of sympathetic activation. Nonlinear analysis of HRV indicated a significant decrease in the Poincare plot SD1 (p = 0.039) and an increase of DFAα2 (p = 0.001) in response to the CPT stress stimulation. Th e systolic BPV parameter LF/HF-sBP increased signifi cantly aft er the CPT (2.84 vs. 3.31; p = 0.019) and was higher than aft er the acoustic startle (3.31 vs. 3.06; p = 0.035). Signifi cantly higher values of diastolic BP (67.17 ± 8.10 vs. 69.65 ± 9.94 mmHg, p = 0.038) and median BP (83.39 ± 8.65 vs. 85.30 ± 10.20 mmHg, p = 0.039) were observed in the CPT group than in the acoustic startle group. C on c l u s i o n s: Th e Cold Pressor Test has a greater stimulatory eff ect on the sympathetic autonomic system in comparison to the unexpected acoustic startle stress. Regardless of whether the stimulation originates from the central nervous system (acoustic startle) or the peripheral nervous system (CPT), the final response is demonstrated by an increase in the low frequency components of blood pressure variability and a decrease in the low and high frequency components of heart rate variability.
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Abstract

The purpose of the study was to estimate in 2012 range and degree of soil contamination due to local diesel fuel leakage spills that occurred in 1980 and from any subsequent activities in the vicinity of the scientific Polish Polar Station in Hornsund, Svalbard. The area of the study covered the immediate vicinity of station buildings including areas of the 1980’s fuel barrel storage depot and location of current fuel tanks. Results of the study were compared with a similar study performed in 1980. As of 2012, areas potentially contaminated covered 0.9 ha, which was a 50% decrease compared to 1980. The area contaminated with total petroleum hydrocarbons was extremely localized. Spread of petroleum hydrocarbons from 1980’s source of pollution investigated 32 years later showed that petroleum derived products were environmentally mobile. Concentrations of total petroleum hydrocarbons in surface soils of the unsaturated active layer above the permafrost decreased significantly mostly due to surface runoff and dispersion through ephemeral drainages. Concentrations of total petroleum hydrocarbons increased with depth through time in sandy soils on the flat area where the largest 1980’s fuel barrel depot was located.
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Abstract

Objectives: In the article we describe the new, high frequency, 20 MHz scanning/Doppler probe designed to measure the flow mediated dilation (FMD) and shear rate (SR) close to the radial artery wall. Methods: We compare two US scanning systems, standard vascular modality working below 12 MHz and high frequency 20 MHz system designed for FMD and SR measurements. Axial resolutions of both systems were compared by imaging of two closely spaced food plastic foils immersed in water and by measuring systolic/diastolic diameter changes in the radial artery. The sensitivities of Doppler modalities were also determined. The diagnostic potential of a high frequency system in measurements of FMD and SR was studied in vivo, in two groups of subjects, 12 healthy volunteers and 14 patients with stable coronary artery disease (CAD). Results: Over three times better axial resolution was demonstrated for a high frequency system. Also, the sensitivity of the external single transducer 20 MHz pulse Doppler proved to be over 20 dB better (in terms of a signal-to-noise ratio) than the pulse Doppler incorporated into the linear array. Statistically significant differences in FMD and FMD/SR values for healthy volunteers and CAD patients were confirmed, p-values < 0:05. The areas under Receiver Operating Characteristic (ROC) curves for FMD and FMD/SR for the prediction CAD had the values of 0.99 and 0.97, respectively. Conclusions: These results justify the usefulness of the designed high-frequency scanning system to determine the FMD and SR in the radial artery as predictors of coronary arterial disease.
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