1,245 research outputs found
A new interpretation of the sedimentary cover in the western Siljan Ring area, central Sweden, based on seismic data
No full textAbstractTwo new reflection seismic profiles over the Paleozoic successions of the western part of the Siljan Ring impact structure show a contrasting seismic signature. The more southerly c. 10km long Mora profile reveals a highly disturbed structure, with only a few kilometers of relatively horizontally layered structures observed. However, interpretations of refracted arrivals in the data, that can be correlated to reflections, indicate the Silurian clastic rocks to be about 200m thick in the central part of the profile. Weak reflections from about 600m depth suggest a 400m thick Ordovician limestone sequence to be present. Cores from the area show a mainly shale lithology for the Silurian and only a thin sequence of Ordovician strata, suggesting a rapid thickening of the Ordovician towards the north. On the more northern c. 12km Orsa profile clear reflections from the Paleozoic successions are seen along the entire profile, except on the southernmost few kilometers. Based on interpretations of refracted arrivals, the Silurian succession appears to be considerably thinner here, and possibly absent at some locations. The Ordovician is also interpreted to be thinner in this area, with a maximum thickness of about 200–300m along most of the profile. A deeper reflection from about 2km within the crystalline basement may represent a dolerite sill. The lack of clear basement reflections on the Mora profile can be attributed to near-surface conditions and the acquisition geometry. The seismic data and recent coring in the area suggest the presence of a deeper paleo-basin towards the southwest with significantly more shales being deposited and the Paleozoic successions being severely disturbed. The shallow coring and seismic data will help form the basis for locating future boreholes for deeper drilling to study impact processes and the Paleozoic evolution of central Sweden
Author Co-Citation Analysis (ACA): a powerful tool for representing implicit knowledge of scholar knowledge workers
No full textIn the last decade, knowledge has emerged as one of the most important and valuable organizational assets. Gradually this importance caused to emergence of new discipline entitled ―knowledge management‖. However one of the major challenges of knowledge management is conversion implicit or tacit knowledge to explicit knowledge. Thus Making knowledge visible so that it can be better accessed, discussed, valued or generally managed is a long-standing objective in knowledge management. Accordingly in this paper author co- citation analysis (ACA) will be proposed as an efficient technique of knowledge visualization in academia (Scholar knowledge workers)
Kompaktní objekty v kategoriích modulů
No full textTitle: Compact objects in categories of modules Author: Peter Kálnai Department: Department of Algebra Supervisor: Mgr. Jan Žemlička, Ph.D., Department of Algebra Abstract: In the thesis we state baic properties of compact objects in various appropriate categories like categories of modules, stable factor category over a perfect ring and Grothendieck categories. We find a ring R such that the class of dually slender R-modules is closed under direct products under some set-theoretic assumption. Finally, we characterize the conditions, when countably generat- ed projective modules are finitely generated, expressed by their Grothendieck monoid. Keywords: compact, dually slender module, stable module category, projective module, self-smal
Kompaktní objekty v kategoriích modulů
No full textTitle: Compact objects in categories of modules Author: Peter Kálnai Department: Department of Algebra Supervisor: Mgr. Jan Žemlička, Ph.D., Department of Algebra Abstract: In the thesis we state baic properties of compact objects in various appropriate categories like categories of modules, stable factor category over a perfect ring and Grothendieck categories. We find a ring R such that the class of dually slender R-modules is closed under direct products under some set-theoretic assumption. Finally, we characterize the conditions, when countably generat- ed projective modules are finitely generated, expressed by their Grothendieck monoid. Keywords: compact, dually slender module, stable module category, projective module, self-smal
Why is unemployment so high in Bulgaria?
No full textThe author seeks to determine the main factors behind poor labor market outcomes in Bulgaria. Unemployment in Bulgaria is high and of long duration. The accumulation of the unemployment stock has been caused by relatively high inflows into unemployment coupled with limited outflows. These features of the Bulgarian labor market are typical of other transition economies in Central Europe and exploring their sources is of broad interest. The author focuses on determinants of and constraints to job creation. He uses data on job creation and job destruction from a survey of employment in all registered firms. He finds that the source of large inflows into unemployment is intensive enterprise restructuring associated with a high pace of job reallocation. However, job creation falls short of job destruction. Three main factors account for the limited job creation and hiring, and thus for low outflows from unemployment: a) The unfriendly business environment, reflected by a low rate of new firm formation, and a relatively small, small and medium enterprise sector. b) Labor market rigidities, including excessive hiring and firing costs. c) Skill and spatial mismatches brought about by enterprise restructuring, as well as low skills and marginalization of the long-term unemployed who cannot successfully compete for new jobs. The author recommends a three pronged strategy to improve labor market performance: (1) removing bureaucratic constraints to entry and expansion of firms; (2) enhancing labor market flexibility through lowering hiring and firing costs; and (3) improving the educational system so as to equip workers with broad and portable skills.Environmental Economics&Policies,Labor Policies,Labor Markets,Public Health Promotion,Health Monitoring&Evaluation,Environmental Economics&Policies,Labor Markets,Health Monitoring&Evaluation,Labor Standards,Banks&Banking Reform
"An Alternative Perspective on Global Imbalances and International Reserve Currencies"
No full textThe stability of the international reserve currency’s purchasing power is less a question of what serves as that currency and more a question of the international adjustment mechanism, as well as the compatibility of export-led development strategies with international payment balances. According to Senior Scholar Jan Kregel, export-led growth and free capital flows are the real causes of sustained international imbalances. The only way out of this predicament is to shift to domestic demand–led development strategies—and capital flows will have to be part of the solution.
The Bromell fossil collection at Uppsala University, Sweden : its history and the people behind it
No full textRemains of 17(th) century cabinets of curiosity collections are held at the Museum of Evolution, Uppsala University, Sweden. Some of the oldest date back to the 1650s, and were included in the collection of Archiater, i.e. physician to the Crown, von Bromell (1679-1731). He is also known for publishing the first series of papers in Sweden to exclusively deal with palaeontology. Throughout his life he acquired specimens by collecting, buying or receiving in exchange to add to those he inherited from his father Olaus Bromelius, a famous botanist and physician. Information on the labels gives a glimpse of his network of friends, colleagues and fellow collectors, such as Kilian Stobaeus, Lars Roberg, Emanuel Swedenborg, Elias Brenner and Johan Dobelius. When Bromell died, his vast collections of books, coins, furniture, conchs, stuffed animals, minerals and fossils were sold off. The minerals and fossils were split up and owned by various persons during the following century. Parts owned by A. Lagerberg between the years 1746 and 1776 were bought in 1796 by Johan Afzelius and donated to Uppsala University at his death. Fossils and minerals earlier described by Bromell were in the care of The Royal Society of Science in Uppsala at least by 1791. Through the Institute of Geology, fossils accumulated over the centuries at Uppsala University eventually came together under the same roof in 1932, under professor Carl Wiman's care at the then newly erected Palaeontology museum building. Today, about 300 fossils from the Bromell collection are preserved at the museum.</p
Hilbert regularity of Z-graded modules over polynomial rings
No full textLet M be a finitely generated Z-graded module over the standard graded polynomial ring R=K[X1,…,Xd] with K a field, and let HM(t)=QM(t)/(1−t)d be the Hilbert series of~M. We introduce the Hilbert regularity of~M as the lowest possible value of the Castelnuovo-Mumford regularity for an R-module with Hilbert series HM. Our main result is an arithmetical description of this invariant which connects the Hilbert regularity of~M to the smallest~k such that the power series QM(1−t)/(1−t)k has no negative coefficients. Finally, we give an algorithm for the computation of the Hilbert regularity and the Hilbert depth of an R-module.The second author was partially supported by the Spanish GovernmentMinisterio de Educaci´on y Ciencia
(MEC), grants MTM2007-64704 and MTM2012–36917–C03–03 in cooperation with the European
Union in the framework of the founds “FEDER”
Hundreds of variants clustered in genomic loci and biological pathways affect human height
No full textMost common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits(1), but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait(2,3). The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P<0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways
Generalized injectivity and approximation
No full textTitle: Generalized injectivity and approximations Author: Serap S¸ahinkaya Department:Algebra Faculty of Mathematics and Physics, Charles University Supervisor: Prof. RNDr. Jan Trlifaj, DSc, Faculty of Mathematics and Physics, Charles University Abstract: Injective modules form a basic class studied in contemporary module theory. One of their generalizations, inspired by tilting theory, is the notion of a cotilting module. While tilting modules behave well with respect to localization, we show that colocalization is the correct approach when comparing the struc- ture of cotilting modules over commutative noetherian rings R with the structure of cotilting modules over their localizations Rm where m runs over the maximal spectrum of R. This is done in Chapter 2 of this Dissertation whose main results were published in the paper [33]. In Chapter 3, we investigate approximation properties of other classic generalizations of injective modules, the Ci- and quasi- injective modules, introduced by Harada et al. Suprisingly, we prove that these classes provide for approximations only in exceptional cases (when all Ci mod- ules are injective, or pure-injective). The Dissertation ends with a set of open problems. Keywords: Commutative noetherian ring, (co)tilting module, (generalized) injec- tive module.
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