954 research outputs found
Multiple criteria decision support in organizational and management chosen problems solving
This article presents an introduction to multicriteria decision making using two decision tools: the Analytic Hierarchy Process (AHP) and its generalization to dependence and feedback – the Analytic Network Process (ANP). The discussion involves theoretical aspects of these methods and some examples of their applications, (e.g. the first application of the ANP, in improving of food quality products, in Poland), in organizational and management problems solving. AHP and ANP introduced by Thomas L. Saaty from the University in Pittsburgh, USA. The Analytic Hierarchy Process has been one of the fastest developing mathematical methods over the recent years used for solving multi-criteria decision problems. The AHP is a general theory of measurement based on some mathematical and psychological principles. In that method a hierarchic decision scheme is constructed, by the breaking the problem into decision elements: goal, criteria, subcriteria, sub-subcriteria (…) and decision alternatives. The goal is on the top of hierarchy, whereas alternatives create the lowest level of hierarchy. The importance of every decision element is established, through the pair-wise comparison of elements on each level of the hierarchic structure, with regard to elements on the level above. To do the comparisons it is using the Saaty’s fundamental scale for paired comparisons for the analysis of both quantitative and qualitative variables. The Analytic Network Process (ANP) is a new theory that extends the Analytic Hierarchy Process (AHP). The basic structures are networks, which allow interactions and feedback within the clusters and between the clusters. So, it can be applied for solving more sophisticated decision problems. Authors’ intention was to showing utility of these methods, which can be successfully applied in the solution of any multicriteria enterprise.multiple criteria decision making methods, Analytic Hierarchy Process (AHP), Analytic Network Process (ANP)
When a year is not enough: Further study of the seasonality of planktonic protist communities structure in an ice-free high arctic fjord (adventfjorden, west spitsbergen)
As a contribution to understanding the ecological framework of protistan seasonal succession patterns, we present the weekly-to-monthly (January–October) light microscopy-based study of nano- and microplanktonic protist communities of Adventfjorden waters in 2013. In general, protist dynamics corresponded to the classic paradigm for the Arctic ice-free waters with extremely low abundance and diversity in winter, with the main abundance and chlorophyll-a peak in April-May, followed by a diverse but low abundant community during summer/autumn. However, the reference of the obtained data to the previously conducted year-round research in 2012 allows us to observe substantial variability in seasonal patterns between the two consecutive years. The most striking difference concerned the spring bloom composition and abundance, with clear domination of Phaeocystis pouchetii in Atlantified fjord waters in 2012 and Bacillariophyceae-dominated (mainly Fragilariopsis, Thalassiosira nordenskioeldii, and, in a lesser extent, also Pseudo-nitzschia seriata) bloom in 2013 when local water prevailed. On the other hand, a surprisingly high share of spring bloom taxa persisted throughout the summer/autumn of 2013 when they co-occurred with typical summer taxa (dinoflagellates and other small flagellates). Their extended growth could, at least in part, result from scarce Ciliophora throughout the season, which, in turn, can be attributed to the high grazing pressure of very numerous meroplankton and mesozooplankton. In light of this, our results may be relevant in discussions proposed for the West Spitsbergen waters link between the Atlantic water inflow and the spring bloom composition, as well as its further progression in the productive season. They also highlight the strong need for further high-resolution monitoring of annual plankton cycles and great caution when looking for phenological patterns within a single year or when interpreting short-term data
Impedance cardiography: Recent advancements
The aim of this paper is the presentation of recent advancements in impedance cardiography
regarding methodical approach, applied equipment and clinical or research implementations.
The review is limited to the papers which were published over last 17 months (dated 2011 and
2012) in well recognised scientific journals. (Cardiol J 2012; 19, 5: 550-556
Anion–Anion Interactions in Aerogen-Bonded Complexes. Influence of Solvent Environment
Ab initio calculations are applied to the question as to whether a AeX5− anion (Ae = Kr, Xe) can engage in a stable complex with another anion: F−, Cl−, or CN−. The latter approaches the central Ae atom from above the molecular plane, along its C5 axis. While the electrostatic repulsion between the two anions prevents their association in the gas phase, immersion of the system in a polar medium allows dimerization to proceed. The aerogen bond is a weak one, with binding energies less than 2 kcal/mol, even in highly polar aqueous solvent. The complexes are metastable in the less polar solvents THF and DMF, with dissociation opposed by a small energy barrier
Lipofuscin-mediated photodynamic stress induces adverse changes in nanomechanical properties of retinal pigment epithelium cells
Abstract Retinal pigment epithelium (RPE) is an important part of the blood-retina barrier (BRB) that separates the retina from the choroid. Although melanin granules contribute to the mechanical stability of the BRB complex, it is unknown if the age pigment lipofuscin affects mechanical properties of the tissue. To address this issue the effect of sub-lethal photic stress mediated by phagocytized lipofuscin granules, isolated from RPE of human donors, on morphology and mechanical properties of ARPE-19 cells was investigated. Nanomechanical analysis using atomic force spectroscopy revealed that irradiation of cells containing lipofuscin granules with blue light induced significant softening of the cells, which was accompanied by substantial reorganization of the cell cytoskeleton due to peroxidation of cellular proteins. Our results indicate that lipofuscin-mediated photic stress can cause significant modification of the RPE cells with the potential to disturb biological function of the BRB complex
The determination of mercury content in the biomass untended for industrial power plant
Biomass is one of the oldest and most widely used renewable
energy sources. The biomass is the whole organic matter of vegetable or
animal origin which is biodegradable. Biomass includes leftovers from
agricultural production, forestry residues, and industrial and municipal
waste. The use of biomass in the power industry has become a standard
and takes place in Poland and other European countries. This paper
discusses the correlation of mercury content in different biomass types
used in the power industry and in products of biomass combustion.
Different biomass types, which are currently burned in a commercial
power plant in Poland, were discussed. A photographic documentation of
different biomass types, such as straw briquettes, wood briquettes, pellets
from energy crops (sunflower husk and wood husk), wood pellets, wood
chips, and agro-biomass (seeds) was carried out. The presented paper
discusses the results obtained for 15 biomass samples. Five selected
biomass samples were burned in controlled conditions in the laboratory at
the University of Silesia. The ash resulting from the combustion of five
biomass samples was tested for mercury content. A total of twenty biomass
samples and its combustion products were tested. Based on the obtained
results, it was found that any supply of biomass, regardless of its type, is
characterized by variable mercury content in dry matter. In the case of e.g.
wood chips, the spread of results reaches 235.1 μm/kg (in dry matter).
Meanwhile, the highest mercury content, 472.4 μm/kg (in dry matter) was
recorded in the biomass of straw, wood pellets, and pellets from energy
crops (sunflower husk). In the case of combustion products of five selected
biomass types, a three or four fold increase in the mercury content has been
observed
The analysis of mercury content in coals and ashes
It is well known that mercury that enters the atmosphere is a serious threat to the natural environment. From the available literature, it can be stated that fossil fuels are among the main carriers of this fuel. The question arises whether it is the right approach. While the enrichment of bituminous coal produces limited amounts of mercury, they are being released into the atmosphere as a result of the combustion of coal. The situation is similar in the case of biomass, which releases large amounts of mercury into the atmosphere when subjected to the combustion process. While bituminous coal is the carrier of mercury, the application of currently known technology, rational production and the use of fossil fuels make it possible to maximally minimize mercury emissions into the atmosphere. This study evaluated the mercury content in the ashes resulting from the combustion of bituminous coal subjected to the enrichment process. The samples were collected from ten mines located in the Polish part of the Upper Silesian Coal Basin (USCB). In total, thirty coal samples and thirty products of the combustion process were examined. All sixty samples were subjected to physicochemical analysis, including: moisture content, ash content, sulfur content, carbon content, and Gross Calorific Value
Modelling, Analysis and Numerical Simulation of a Spring-Rods System with Unilateral Constraints
In this paper we consider a mathematical model which describes the
equilibrium of two elastic rods attached to a nonlinear spring. We derive the
variational formulation of the model which is in the form of an elliptic
quasivariational inequality for the displacement field. We prove the unique
weak solvability of the problem, then we state and prove some convergence
results, for which we provide the corresponding mechanical interpretation.
Next, we turn to the numerical approximation of the problem based on a finite
element scheme. We use a relaxation method to solve the discrete problems that
we implement on the computer. Using this method, we provide numerical
simulations which validate our convergence results.Comment: 24 pages, 8 figure
Primary producers and production in Hornsund and Kongsfjorden - Comparison of two fjord systems
Hornsund and Kongsfjorden are two similar-sized Arctic fjords on the West coast of Spitsbergen. They are influenced by cold coastal Arctic water (Hornsund) and warmer Atlantic water (Kongsfjorden). Environmental conditions affect the timing, quantity, spatial distribution (horizontal and vertical) of spring and summer blooms of protists as well as the taxonomic composition of those assemblages. Here, we compile published data and unpublished own measurement from the past two decades to compare the environmental factors and primary production in two fjord systems. Kongsfjorden is characterized by a deeper euphotic zone, higher biomass and greater proportion of autotrophic species. Hornsund seems to obtain more nutrients due to the extensive seabird colonies and exhibits higher turbidity compared to Kongsfjorden. The annual primary production in the analysed fjords ranges from 48 g C m-2 y-1 in Kongsfjorden to 216 g C m-2 y-1 in Hornsund, with a dominant component of microplankton (90%) followed by macrophytes and microphytobenthos
Red ear syndrome – Case report and review of literature
Red ear syndrome is characterized by: paroxysmal, unilateral, recurrent pain, redness and discomfort of the ear lobe accompanied by a burning sensation. The duration and frequency of red ear syndrome attacks is very various and the episodes, usually occur spontaneously. The pathophysiology is still unknown and also there are no medications with approved efficacy. The goal of this brief report is to present a 11-year old girls whose symptoms of red ear syndrome preceded migraine without aura and the signs of redness of the ear occurred in clusters. The occurrence of symptoms of our case may have confirmed the observation that red ear syndrome is associated with primary headaches particularly migraine and cluster headaches. The literature on this case report of pediatric idiopathic red ear syndrome has been reviewed
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