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1662. Algebraic integrability for minimum energy curves
- Creator:
- Yudin, Ivan and Silva Leite, Fátima
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Darboux polynomials, drag power, Euler-Lagrange equations, grading, integrability, and vector fields
- Language:
- English
- Description:
- This paper deals with integrability issues of the Euler-Lagrange equations associated to a variational problem, where the energy function depends on acceleration and drag. Although the motivation came from applications to path planning of underwater robot manipulators, the approach is rather theoretical and the main difficulties result from the fact that the power needed to push an object through a fluid increases as the cube of its speed.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1663. Algebraic solution to box-constrained bi-criteria problem of rating alternatives through pairwise comparisons
- Creator:
- Krivulin, Nikolai
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- idempotent semifield, tropical optimization, constrained bi-criteria decision problem, Pareto-optimal solution, box constraints, and pairwise comparisons
- Language:
- English
- Description:
- We consider a decision-making problem to evaluate absolute ratings of alternatives that are compared in pairs according to two criteria, subject to box constraints on the ratings. The problem is formulated as the log-Chebyshev approximation of two pairwise comparison matrices by a common consistent matrix (a symmetrically reciprocal matrix of unit rank), to minimize the approximation errors for both matrices simultaneously. We rearrange the approximation problem as a constrained bi-objective optimization problem of finding a vector that determines the approximating consistent matrix, and then represent the problem in terms of tropical algebra. We apply methods and results of tropical optimization to derive an analytical solution of the constrained problem. The solution consists in introducing two new variables that describe the values of the objective functions and allow reducing the problem to the solution of a system of parameterized inequalities constructed for the unknown vector, where the new variables play the role of parameters. We exploit the existence condition for solutions of the system to derive those values of the parameters that belong to the Pareto front inherent to the problem. Then, we solve the system for the unknown vector and take all solutions that correspond to the Pareto front, as a complete solution of the bi-objective problem. We apply the result obtained to the bi-criteria decision problem under consideration and present illustrative examples.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1664. Algebras and spaces of dense constancies
- Creator:
- Bella, Angelo, Martinez, Jorge, and Woodward, Scott D.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- space and algebra of dense constancy and $c$-spectrum
- Language:
- English
- Description:
- A DC-space (or space of dense constancies) is a Tychonoff space $X$ such that for each $f\in C(X)$ there is a family of open sets $\lbrace U_i\: i\in I\rbrace $, the union of which is dense in $X$, such that $f$, restricted to each $U_i$, is constant. A number of characterizations of DC-spaces are given, which lead to an algebraic generalization of the concept, which, in turn, permits analysis of DC-spaces in the language of archimedean $f$-algebras. One is led naturally to the notion of an almost DC-space (in which the densely constant functions are dense), and it is shown that all metrizable spaces have this property.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1665. Algesthesia after epileptic seizure
- Creator:
- Jan Mareš and Richard Rokyta
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Patologie. Klinická medicína, patologie, epileptické záchvaty, analgezie, krysa obecná, pathology, epileptic seizures, analgesia, Rattus rattus, nociception, flurothyl, postictal analgesia, 14, and 616
- Language:
- English
- Description:
- The consequences of epileptic seizures related to postictal inhibition in early postictal period include postictal analgesia. We studied this phenomenon over 96 h following flurothyl-induced seizures in adult male Wistar rats. Nociception of control (no seizure) and seizured groups were tested using the plantar and von Frey hair tests. We determined latency of forepaw and hind paw reactions using plantar tests and the number of von Frey hairs reactions. Shortly after seizures, longer plantar test latencies were seen relative to the control group. Before the seizures the plantar test reaction times were significantly shorter in forepaws than in hind paws. The effect disappeared post-seizure and surprisingly, it also disappeared at the corresponding time in controls; it reappeared after 48 h in the seizure group and after 24 h in controls. Differences in the von Frey hairs test occurred at 5 and 60 min post-seizure, however, these differences could not be explained by limb anatomy; although, different thermal and mechanical nociception mechanisms could be significant. The unexpected reactions in controls could be related to brief social and physical interactions between the two groups. and J. Mareš, R. Rokyta.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1666. Alginate matrices for protein delivery: a short review
- Creator:
- Wawrzyńska, E and Dana Kubies
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- algináty, růstové faktory, alginates, growth factors, biomaterials, protein release, growth factor release, 14, and 612
- Language:
- English
- Description:
- Growth factors are powerful molecules that regulate cellular growth, proliferation, healing, and cellular differentiation. A delivery matrix that incorporates growth factors with high loading efficiencies, controls their release, and maintains bioactivity would be a powerful tool for regenerative medicine. Alginate has several unique properties that make it an excellent platform for the delivery of proteins. Mild gelling conditions can minimize the risk of protein denaturation; moreover, alginate can serve as protection from degradation until protein release. Various modifications have been proposed to tune alginate binding and release proteins, simultaneously adjusting alginate degradability, mechanical stiffness, swelling, gelation properties and cell affinity. The primary objective of this article is to review the literature related to recent advances in the application of alginate matrices in protein delivery in regenerative medicine. A special emphasis is put on the relevance of delivery of growth factors and chemokine., E. Wawrzyńska, D. Kubies., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1667. Alice Teichova :
- Type:
- text and bibliografie
- Subject:
- Bibliografie. Katalogy, Teichová, Alice,, historici čeští, bibliografie personální, and personální bibliografie
- Language:
- English
- Rights:
- unknown
1668. Alien Enemy Civilians in the War. Austrian, Hungarian, and American Citizens Living in Alien Territories from 1917 to 1918 /
- Creator:
- Horčička, Václav,
- Type:
- text and studie
- Subject:
- Mezinárodní vztahy, světová politika, válka první světová (1914-1918), Rakušané, Američané, Maďaři, vztahy habsburská monarchie-USA, internace, Habsburská monarchie, USA, světové dějiny 1914-1918, zahraniční politika, mezinárodní vztahy, and dějiny vojenství
- Language:
- English
- Rights:
- unknown
1669. Alien fish species in the Czech Republic and their impact on the native fish fauna
- Creator:
- Lusk, Stanislav, Lusková, Věra, and Hanel, Lubomír
- Type:
- article and TEXT
- Subject:
- introduction, translocation, and invasion
- Language:
- English
- Description:
- Over the past 150 years, the waters of the Czech Republic were experimentally stocked or invaded by a total of 41 alien (non-native) fish species. The following species have become fully naturalized and produced self-sustained populations: Carassius gibelio, Pseudorasbora parva, Ameiurus nebulosus and Gasterosteus aculeatus, which produced stable populations in several spatially limited localities. In some cases Oncorhynchus mykiss, Salvelinus fontinalis and Coregonus maraena will produce instable temporary populations based on released material obtained from fish farms and ponds. The occurrence of the remaining acclimatized alien species (Coregonus peled, Ctenopharyngodon idella, Hypophthalmichthys molitrix, Aristichthys nobilis) in natural ecosystems and fishponds depends on stocking fish obtained from artificial spawning and cultures. The documented annual average production of alien species fit for human consumption amounts to around 2 000 tonnes, i.e. 8.2 % of the annual average production of marketable fish cultures in the Czech Republic. A significant negative impact of the introduced species on native ichthyofauna has been ascertained as regards its ecological, biological properties, biodiversity and health. Considered a typical invasive alien species, Carassius gibelio heavily depressed the occurrence and numbers of indigenous Carassius carassius populations and also contributed to the decreased numbers of Tinca tinca, Leucaspius delineatus and other native cyprinid fish. P. parva and A. nebulosus show a much weaker and limited impact. The introduction of C. idella was accompanied by the introduction of the tapeworm species, Bothriocephalus gowkongensis, which subsequently caused heavy losses in cultures of Cyprinus carpio. In 2008, Neogobius melanostomus was recorded for the first time in this country at the confluence of the Morava and Dyje rivers.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/
1670. Alien flora of Europe: species diversity, temporal trends, geographical patterns and research needs
- Creator:
- Lambdon, Philip W., Pyšek, Petr, Basnou, Corina, Hejda, Martin, Arianoutsou, Margarita, Essl, Franz, Jarošík, Vojtěch, Pergl, Jan, Winter, Marten, Anastasiu, Paulina, Andriopoulos, Pavlos, Bazos, Ioannis, Brundu, Giuseppe, Celesti-Grapow, Laura, Chassot, Philippe, Delipetrou, Pinelopi, Josefsson, Melanie, Kark, Salit, Klotz, Stefan, Kokkoris, Yannis, Kühn, Ingolf, Marchante, Hélia, Perglová, Irena, Pino, Joan, Vilà, Montserrat, Zikos, Andreas, Roy, David, and Hulme, Philip E.
- Type:
- article and TEXT
- Subject:
- alien plants, biogeographical pattern, donor regions, Europe, habitat affinity, naturalization, neophytes, plant invasions, residence time, and temporal trends
- Language:
- English
- Description:
- The paper provides the first estimate of the composition and structure of alien plants occurring in the wild in the European continent, based on the results of the DAISIE project (2004–2008), funded by the 6th Framework Programme of the European Union and aimed at “creating an inventory of invasive species that threaten European terrestrial, freshwater and marine environments”. The plant section of the DAISIE database is based on national checklists from 48 European countries/regions and Israel; for many of them the data were compiled during the project and for some countries DAISIE collected the first comprehensive checklists of alien species, based on primary data (e.g., Cyprus, Greece, F. Y. R. O. Macedonia, Slovenia, Ukraine). In total, the database contains records of 5789 alien plant species in Europe (including those native to a part of Europe but alien to another part), of which 2843 are alien to Europe (of extra-European origin). The research focus was on naturalized species; there are in total 3749 naturalized aliens in Europe, of which 1780 are alien to Europe. This represents a marked increase compared to 1568 alien species reported by a previous analysis of data in Flora Europaea (1964–1980). Casual aliens were marginally considered and are represented by 1507 species with European origins and 872 species whose native range falls outside Europe. The highest diversity of alien species is concentrated in industrialized countries with a tradition of good botanical recording or intensive recent research. The highest number of all alien species, regardless of status, is reported from Belgium (1969), the United Kingdom (1779) and Czech Republic (1378). The United Kingdom (857), Germany (450), Belgium (447) and Italy (440) are countries with the most naturalized neophytes. The number of naturalized neophytes in European countries is determined mainly by the interaction of temperature and precipitation; it increases with increasing precipitation but only in climatically warm and moderately warm regions. Of the nowadays naturalized neophytes alien to Europe, 50% arrived after 1899, 25% after 1962 and 10% after 1989. At present, approximately 6.2 new species, that are capable of naturalization, are arriving each year. Most alien species have relatively restricted European distributions; half of all naturalized species occur in four or fewer countries/regions, whereas 70% of non-naturalized species occur in only one region. Alien species are drawn from 213 families, dominated by large global plant families which have a weedy tendency and have undergone major radiations in temperate regions (Asteraceae, Poaceae, Rosaceae, Fabaceae, Brassicaceae). There are 1567 genera, which have alien members in European countries, the commonest being globally-diverse genera comprising mainly urban and agricultural weeds (e.g., Amaranthus, Chenopodium and Solanum) or cultivated for ornamental purposes (Cotoneaster, the genus richest in alien species). Only a few large genera which have successfully invaded (e.g., Oenothera, Oxalis, Panicum, Helianthus) are predominantly of non-European origin. Conyza canadensis, Helianthus tuberosus and Robinia pseudoacacia are most widely distributed alien species. Of all naturalized aliens present in Europe, 64.1% occur in industrial habitats and 58.5% on arable land and in parks and gardens. Grasslands and woodlands are also highly invaded, with 37.4 and 31.5%, respectively, of all naturalized aliens in Europe present in these habitats. Mires, bogs and fens are least invaded; only approximately 10% of aliens in Europe occur there. Intentional introductions to Europe (62.8% of the total number of naturalized aliens) prevail over unintentional (37.2%). Ornamental and horticultural introductions escaped from cultivation account for the highest number of species, 52.2% of the total. Among unintentional introductions, contaminants of seed, mineral materials and other commodities are responsible for 1091 alien species introductions to Europe (76.6% of all species introduced unintentionally) and 363 species are assumed to have arrived as stowaways (directly associated with human transport but arriving independently of commodity). Most aliens in Europe have a native range in the same continent (28.6% of all donor region records are from another part of Europe where the plant is native); in terms of species numbers the contribution of Europe as a region of origin is 53.2%. Considering aliens to Europe separately, 45.8% of species have their native distribution in North and South America, 45.9% in Asia, 20.7% in Africa and 5.3% in Australasia. Based on species composition, European alien flora can be classified into five major groups: (1) north-western, comprising Scandinavia and the UK; (2) west-central, extending from Belgium and the Netherlands to Germany and Switzerland; (3) Baltic, including only the former Soviet Baltic states; (4) east-central, comprizing the remainder of central and eastern Europe; (5) southern, covering the entire Mediterranean region. The clustering patterns cut across some European bioclimatic zones; cultural factors such as regional trade links and traditional local preferences for crop, forestry and ornamental species are also important by influencing the introduced species pool. Finally, the paper evaluates a state of the art in the field of plant invasions in Europe, points to research gaps and outlines avenues of further research towards documenting alien plant invasions in Europe. The data are of varying quality and need to be further assessed with respect to the invasion status and residence time of the species included. This concerns especially the naturalized/casual status; so far, this information is available comprehensively for only 19 countries/regions of the 49 considered. Collating an integrated database on the alien flora of Europe can form a principal contribution to developing a European-wide management strategy of alien species.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/