Search Results

You are looking at 1 - 10 of 31 items for

  • Author: Tomasz Zieliński x
Clear All Modify Search
Open access

Tomasz Salamon and Tomasz Zieliński

Unusual development of sandur sedimentary succession, an example from the Pleistocene of S Poland

An atypical lithological development of outwash deposits in the Carpathians Foreland (S Poland) shows lower and middle parts of the sedimentary succession that are characterized by sinuous palaeochannels. This channel facies consists of laterally accreted sands derived from side bars. The sedimentary environment was a proglacial system of anabranching channels, presumably of anastomosed type. The outwash channel pattern was most probably controlled by the raising base level of the fluvial system. Both proglacial and extraglacial waters were dammed by a sandur within a small upland valley. Aggradation and progradation of the glaciofluvial deposits resulted in progressive rising of the dammed lake level. The low hydraulic gradient of the outwash streams resulted in a sinuous planform as well as a low-energy style of deposition. Afterwards, the rising lake water was drained off through a low watershed and the entire valley became filled with outwash sediments. The bedrock morphology thus became buried and a typical unconfined sandur with a braided channel network developed during the last phase of the glaciomarginal sedimentation (upper part of the sedimentary succession under study).

Open access

Tomasz Zieliński

Abstract

Systemic risk is a fundamental constituent of contemporary financial systems. For the past decades a growing number of abrupt upsets in financial systems could be observed. Due to previous experiences, politicians and regulators prefer to identify the offenders outside the system or to blame one of the entities inside the system. However, nowadays many disasters in anthropogenic systems cannot be perceived that way. They are often results of inappropriate interactions rather than external or internal impulses. This requires a paradigm shift in thinking about systemic risk. A component-oriented perspective should be nowadays replaced with a network-oriented view. Closer insight into the concept of systemic risk can refer to the model of the system composed of a huge number of interconnected components. In such a system, systemic risk is usually considered to have a ‘cascading’, ‘domino’ or ‘contagion’ effect, resulting from strong connections. An initial failure could have disastrous effects and cause extreme damage as the number of network nodes goes to infinity. Strongly interconnected, complex dynamic systems cannot be understood by the simple sum of their components’ properties, in contrast to loosely coupled systems. What makes the behaviour of complex financial systems particularly unpredictable is that systemic failures may occur even if everybody involved is highly skilled, highly motivated and behaving properly.

Open access

Tomasz Zieliński and Bogusław Antoszewski

Abstract

The paper presents a 25-year-old woman who is using a strict diet of 1000 kcal lost 83 kg in 18 months. Despite her young age, weight loss caused numerous cutaneous fatty folds, because her skin was not elastic or resilient enough. The patient undergo a multi-stage surgical treatment aiming to rectify the deformations. This example illustrates the problems of patients having undergone intensive slimming procedures and presents surgical treatment methods that rectify typical deformations in these patients.

Open access

Tomasz Zieliński and Krzysztof Duda

Frequency and Damping Estimation Methods - An Overview

This overview paper presents and compares different methods traditionally used for estimating damped sinusoid parameters. Firstly, direct nonlinear least squares fitting the signal model in the time and frequency domains are described. Next, possible applications of the Hilbert transform for signal demodulation are presented. Then, a wide range of autoregressive modelling methods, valid for damped sinusoids, are discussed, in which frequency and damping are estimated from calculated signal linear self-prediction coefficients. These methods aim at solving, directly or using least squares, a matrix linear equation in which signal or its autocorrelation function samples are used. The Prony, Steiglitz-McBride, Kumaresan-Tufts, Total Least Squares, Matrix Pencil, Yule-Walker and Pisarenko methods are taken into account. Finally, the interpolated discrete Fourier transform is presented with examples of Bertocco, Yoshida, and Agrež algorithms. The Matlab codes of all the discussed methods are given. The second part of the paper presents simulation results, compared with the Cramér-Rao lower bound and commented. All tested methods are compared with respect to their accuracy (systematic errors), noise robustness, required signal length, and computational complexity.

Open access

Piotr Zieliński and Tomasz Suchowolec

Abstract

Five parallel channels of the Narew River (NE Poland) were hydromorphologically assessed with the River Habitat Survey (RHS) method. Four out of the five studied channels were partly separated from the functioning system of the anastomosing river by a dike for more than 20 years, and were subjected to gradual overgrowing and shallowing. In the 1990’s and in 2002, a number of renaturisation measures were implemented, restoring sufficient discharge for the channels to make them active again. The Habitat Modification Score (HMS) obtained as a result of the survey only classifies the fragment ecologically to the third class of streams with high HMS value in the case of the current main channel of the Narew River (largely formed in an artificial manner). This suggests substantial anthropogenic changes in the river channel and its vicinity. The aggregate values of the Habitat Quality Assessment (HQA) index suggest the preservation of numerous environmentally valuable elements at all of the five studied sites of the anastomosing Narew River system. This even concerns channels which remained almost separated and functioned as oxbow lakes for more than 20 years. The highest HQA values were recorded in the case of the channel constituting the main channel before the regulation, and a neighbouring regulated channel currently fulfilling the function of the main water course in this cross-section. In spite of long-term negative changes, the studied fragment of the ecosystem of the anastomosing river is distinguished by high resistance to “anthropogenic stress”, and high capacity for spontaneous restoration of a state close to the natural one. Although lotic ecosystems constitute elements of the natural environment particularly sensitive to anthropopressure, they retain the ability to regenerate for a long time, under the condition of providing them with relevant hydrological and ecological conditions.

Open access

Tomasz Zieliński

Abstract

The present study revolves around the identification of the stratigraphical boundary between Pleistocene formations that formed prior to the first advance of the Scandinavian ice sheet (Early Pleistocene, i.e., the so-called preglacial) and the overlying, glacially derived deposits (Middle Pleistocene). In particular, it focuses on variation in heavy mineral assemblages, which are an important tool for stratigraphers. The Neogene basement, described here, was most often the source of material that was redeposited by Early Pleistocene rivers. The geological structure and Early Pleistocene palaeogeographical scenarios for various Polish regions are discussed. Moreover, comparisons with other European preglacial formations are carried out. The mineral spectrum of Lower Pleistocene deposits is largely dependent of rocks of the Neogene and Mesozoic basement. If the incision of ancient catchments was into terrigenous rocks, the stratigraphical boundary between preglacial and glacial formations is easily determined with the help of a heavy mineral analysis. As a rule, this coincides with a noticeable change from resistant to non-resistant mineral associations. Such cases are noted for successions in central Poland and eastern England. On the other hand, outcrops of igneous or metamorphic rocks exist within preglacial river catchments in most parts of Europe. They were the local sources of non-resistant heavy minerals long before their glacial supply from the Baltic Shield. In these cases, mineralogical analysis fails in the search for the Early/Middle Pleistocene transition.

Open access

Beata Gruszka, Wojciech Morawski and Tomasz Zieliński

Sedimentary record of a Pleistocene ice-sheet interlobate zone (NE Poland)

Well developed NE-SW trending corridors of outwash in NE Poland are associated with a series of lakes with a similar direction of elongation. The glaciofluvial corridor under study consists of parallel ridges with associated channels and kames. The deposits are flanked by till and hummocky terrain. The gravel ridges are composed of sand and gravel deposits that are cross-stratified, massive or graded, and that contain cut-and-fill structures and large intra-clasts of sand and gravel. Locally the deposits show normal faults. The succession of one of the ridges is interpreted to reflect the infilling of a braided channel in a crevasse. Sedimentation took place in some phases when the ice-sheet regime changed from active to stagnant. Sandy-gravel ridges occur within this complex perpendicular to the Weichselian ice-sheet margin.

The corridor is interpreted as an interlobate area in the zone between the Warmia and Mazury ice lobes. The braided-channel deposits are not comparable to typical Polish sandurs. The lithofacies characteristics show higher energy conditions, and the channels are deeper than those typical of Pleistocene lowland sandurs. The sand and gravel ridges are interpreted as interlobate eskers.

Open access

Monika Zielińska, Piotr Zieliński and Tomasz Mokwa

Juvenile Blackbird (Turdus merula) moulting primaries and secondaries

Open access

Aleksandra Iljin, Andrzej Zieliński, Edward Lewandowicz, Bogusław Antoszewski and Tomasz Zieliński

Abstract

The aim of the study was evaluation of the results of surgical treatment of congenital blepharoptosis (CBP) using Mustarde’s modified method.

Material and methods. Between 2005-2014 forty eight children with CBP underwent surgical correction of CBP by Mustarde’s modified method. Basing on the results of ophthalmic and orthoptic examination, and standard measurements, we estimated postoperative difference in the position and symmetry of the upper eyelids, and postoperative complications in our patients.

Results. Very good results were obtained in all cases with mild, in 89.5% with moderate, and in 85.7% with severe unilateral CBP after correction by Mustarde’s modified method. Lagophthalmos was seen in 6.25%, and undercorrection in 12.5% of cases.

Conclusions. 1. Mustarde’s modified method allows for obtaining very good functional and aesthetic results in CBP patients. 2. Mustarde’s modified method is a valuable supplemental surgical technique in CBP, and contributes to a low rate and small range of lagophthalmos.

Open access

Tomasz Zieliński, Piotr Czyżewski and Marek Szczepkowski

Abstract

The operation to restore the continuity of the gastrointestinal tract is another surgical intervention in a given patient, which directly translates into an increased risk of complications during and after surgery. That is why proper qualification is important for the operation to restore the continuity of the gastrointestinal tract in terms of performance and efficiency of the anal sphincter apparatus, among other things.

The aim of the study was to evaluate the effect of restoring physiological defecation routes on the sphincter function and to observe the parameters of anorectal manometry in patients before and after surgery to restore the continuity of the gastrointestinal tract.

Material and methods. The study included 29 patients scheduled for restoration of the continuity of the gastrointestinal tract, 12 women and 17 men. The average age in the group was 62 years. Anorectal manometry was performed both before surgery as well as one month and three months afterwards in all patients. The average time to have a stoma was 12 months.

Results. The resting pressure in the anal canal (MRP) three months after the restoration of the continuity of the gastrointestinal tract increased by 30.4%. The maximum systolic blood pressure in the anal canal (MSP) increased by 22.2%. The value of recto-anal inhibitory reflex (RAIR) decreased by 19.2%. The length of the high pressure zone in the anal canal (HPZL) increased by 27%. The study results of visceral rectal sensation thresholds decreased by 23.3% for the sensation threshold, and 14.4% for the pressure threshold.

Conclusions. Restoring the continuity of the gastrointestinal tract improves the anal sphincter function which is evident in the parameters of anorectal manometry. The restoration of passage improves the sphincter function, and these changes are statistically significant.