An inverse semigroup $S$ is pure if $e=e^2$, $a\in S$, $e<a$ implies $a^2=a$; it is cryptic if Green's relation $\mathcal {H}$ on $S$ is a congruence; it is a Clifford semigroup if it is a semillatice of groups. We characterize the pure ones by the absence of certain subsemigroups and a homomorphism from a concrete semigroup, and determine minimal nonpure varieties. Next we characterize the cryptic ones in terms of their group elements and also by a homomorphism of a semigroup constructed in the paper. We also characterize groups and Clifford semigroups in a similar way by means of divisors. The paper also contains characterizations of completely semisimple inverse and of combinatorial inverse semigroups in a similar manner. It ends with a description of minimal non-$\mathcal {V}$ varieties, for varieties $\mathcal {V}$ of inverse semigroups considered.
Morphological characteristics of ripples are analyzed considering bed surfaces as two dimensional random fields of bed elevations. Two equilibrium phases are analyzed with respect to successive development of ripples based on digital elevation models. The key findings relate to the shape of the two dimensional second-order structure functions and multiscaling behavior revealed by higher-order structure functions. Our results suggest that (1) the two dimensional second-order structure functions can be used to differentiate the two equilibrium phases of ripples; and (2) in contrast to the elevational time series of ripples that exhibit significant multiscaling behavior, the DEMs of ripples at both equilibrium phases do not exhibit multiscaling behavior.
The larval period in fishes has several definitions, each one deviating slightly from the other. Small discrepancies in the definitions, especially concerning the end of the larval period, can create misunderstandings when applied in practice. I examine the different definitions of a larva, the larval period, including metamorphosis, and the juvenile period. Various criteria used to identify the transition from the larval to juvenile periods are contradictory and refer mostly to the length of the larval period. Ignorance of definitions used to identify the juvenile period has caused many larvae to be regarded as juveniles. I discuss the feasibility of various definitions and the nomenclature on the basis of character evaluation. The occurrence of larval morphological characters, i.e. larval fin fold, differentiation of fins, temporary organs, absence of scale cover, non-adult like body proportions and pigmentation, is examined and some features are compared in eleven species. Irrespective of the different definitions of a larva, there are considerable differences in the schedule and duration of development in certain characters between species and, in terms of duration, also within species owing to environmental conditions. Ontogenetic processes seem to be sufficiently flexible to allow larvae to adapt to their environment, which on the other hand may also shape the phenotype. Determination of the environment in which a larva develops depends not only on the location of the spawning grounds but also on the dispersion of larvae. Dispersal strategies are examined in light of larval morphology and behaviour. After fin differentiation, the transition from larva to juvenile would seem to be best described by the dominant morphological changes in body proportions and coloration, combined with behavioural aspects and habitat changes. I suggest the differences and functional aspects of larvae be examined. The main character of larvae is that they are adapted to make use of resources not normally used by adults.
The aim of this paper is to analyze changes in fertility in Slovakia in interwar period and to describe its overall character in transversal and longitudinal perspective. The article is based on data from vital statistics of Statistical office. Special attention is paid to the level of concious fertility control and spatial differencies. and Branislav Šprocha, Pavol Tišliar.
The focus of the research was an anthropological and archeological rescue excavation of the site Majetín - Náves. This research was conducted by workers of Archaeological Centre Olomouc during September end October 2012. The aim of the research was to verify a potentional of this site, which is located on the northern border of the village.
Decarburization as a common adverse effect at manufacturing and processing steel semiproducts. Loses caused by surface decarburization. Initial basis for solution of GAČR project - magnetic diagnostics of decarburization. Selection of steel, temperature and exposition times at oxidizing atmosphere. Surfaces with oxide layers, after pickling, shot-blasted. Surface diagnostics by x-ray diffraction - crystals, structure, texture, stregthening, internal stress; decarburization evaluation after ČSN EN standard. Intention of project solution. and Oduhličení jako běžný doprovodný nepříznivý jev při výrobě a zpracování ocelových polotvarů. Ztráty z titulu oduhličení povrchů. Výchozí podklady pro řešení projektu GAČR - magnetické diagnostiky oduhličení. Volba oceli, teploty a časy expozice v oxidační atmosféře. Povrchy s vrstvami kysličníků, po moření, upravené tryskáním. Diagnostika povrchu RTG difrakcí - krystaly, struktura, textura, zpevnění, vnitřní pnutí; hodnocení oduhličení podle ČSN EN. Záměr řešení projektu.
This article examines the development of panel studies and their main characteristics. The first part of this article outlines the historical development of panel studies. Here special reference is made to the first panel studies ever undertaken, and the influence of Paul Lazarsfeld on this field of research. Thereafter, there is an overview of some recent national panel studies, and different approaches used in the analysis of panel data. The second part of this article concentrates on the panel study as a type of longitudinal research where special attention is given to a number of issues: unit of analysis, mode of data collection, time span between waves of data collection, duration of panel studies, research themes and policy influences, and opportunities for studying change at the individual (micro) level. In the final section, there is a discussion of the specific difficulties associated with panel study research., Zdeňka Lechnerová., and Obsahuje bibliografii a bibliografické odkazy
Prezentovaný príspevok uvádza hlavné charakteristiky fluorescenčného farbiva merocyanínu 540 (MC 540), jeho interakciu s biologickými membránami a prehĺad jeho biofyzikálnych a biomedicínskych aplikácií. Dôraz je kladený na najnovšie možnosti aplikácií MC 540, a to v cytometrickej detekcii kapacitácie spermií a prokoagulačnej aktivite trombocytov, v elektroforetickej analýze alifatických karboxylových kyselín a peptidov a v optických senzoroch pro stanovenie amónia v pôde a vodných sedimentoch., Libuša Šikurová., and Obsahuje seznam literatury