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The theoretical concept of the biological species and the multidimensional species category, as currently applied by a majority of ornithologists and by many other biologists, replaced the typological-morphological species concept during the first half of this century and became a central tenet of the synthetic theory of evolution. The concept of biospecies is a 'horizontal' concept referring to contemporary reproductive communities at any particular period, e.g. the Recent period or any other time level of the geological past. Historical 'species' concepts as applied by cladists and palaeontologists refer to artificially delimited portions of 'vertical' phyletic lineages for which the application of the term 'species' causes severe problems. Discussions would be simplified if the concept and term 'species' was to be restricted to cross sections of phyletic lineages at any time level and a separate taxonomy outside the Linnaean system of genera and species was to be conceived to deal with phyletic lineages. Under each of the theoretical species concepts, species taxa are assigned broadly to intermediate or narrowly defined taxonomic species categories. Ornithologists of the 19th century applied morphological species concepts, emphasizing morphological character differences between species (rather than distinctness) and the fertility of con specific individuals (rather than the isolation from non-conspecific populations). Nearly all leading museum ornithologists in 19th-century Europe delineated monotypic Linnaean species, whereas the explorer-naturalists of the Gloger-Middendorff school (including Panas, Faber, Gloger, Nordmann, Middendorff, Schrenck, Radde, as well as Schlegel and Blasius) delimited widely circumscribed species taxa. Their researches in the vast territories of eastern Europe, Siberia and the Far East from the late 18th century to the 1880s and, in particular, their rich specimen material, demonstrated direct intergradation of many taxa (geographical varieties) of birds, thus revealing the conspecific nature of numerous narrowly conceived morphospecies previously described by museum workers. The ornithologists of the Gloger-Middendorff school also studied several conspicuous phenomena of geographical character variation in birds (and mammals) across Eurasia, especially plumage colouration (and pelage) and body size, but none of them was an evolutionist. They an adhered to a typological-creationist theoretical species concept. During the late 19th century, the museum specialists' taxonomic notion of narrow morphospecies dominated systematic ornithology in Europe, overtaking the work of the naturalists of the Gloger-Middendorff school, which fell into oblivion. The ornithologists of the Bairdian school in North America (Baird, Coues, Allen, Ridgway) further developed the concept of subspecies after the 1850s and especially from the 1870s onward. Their views were fully in accord with Darwin's theories of evolution' thus they defined the subspecies in a somewhat simplified manner as 'nascent species': These ornithologists were able to base their studies on collections of extensive specimen material which they had obtained during a series of exploring expeditions across the North American continent. Their studies led to the discovery of many aspects of both individual and geographic variation in birds. There are interesting historical similarities between the coinciding taxonomic interpretations and the comparable application of fairly broad limits of morphospecies by the North American ornithologists and the earlier exploring ornithologists in Europe, arrived at Independently by these, research groups, The study of specimens in 'series' (,suites'), beginninng with the naturalists of the Gloger-Middendorff school and, in particular, with the naturalists of the Bairdian school in North America, eventually led to the overcoming of the prevating typological view of variation and the development of 'population thinking'. Influenced by the work of Henry Seebohm in Britain and that of the North American ornithologists, Hartert in England and Kleinschmidt in Germany jointly succeeded in overcoming the strong opposition of the leadi.ng ornithologists in Europe during the 1890s and early 19008 and introduced a concept which soon developed into the biological species concept through the work of Stresemann, Rensch, and in particular, Ernst Mayr. Hopefully, ornithologists will continue the study of taxa at low, intermediate and high levels of microtaxonomic differentiation and will identify the subspecies groups, biological species and the biogeographical species in the world's avifaunas. Cladistic analyses will provide historical {'vertical'} overviews of phyletic lineages at different taxonomic levels.
Speakers of various Southern german dialects may be heard to use two syntactic variants of subordinate clauses which are represented by the following Swabian examples: (1) daß er den net will komme lasse (2) daß er den net komme lasse will Of these two variants of the three-element verbal complex, only the non-dialect counterpart of (2) is accepted as standard modern written German: (3) daß er ihn nicht kommen lassen will In earlier periods of the German language, however, both variants were used by authors of written texts.
Classical mutagenesis
(1992)
Classical genetic analyses require the presence of at least two different alleles per locus. Until the mid 1920's for the different alleles the investigators had to rely on spontaneous mutations. Since then mutagenic agents (mutagens) became available and these discoveries greatly enhanced the power of genetic analyses. Mutation is defined here as a heritable chemical alteration within the gene or the mutation process bringing about the change. Mutant is the individual (cell) containing the mutation. Point mutations are assumed to be free of loss, gain or rearrangement within the nucleotide sequence. Fonvard mutations are changes from the wild type allele (the allele predominant in wild populations) to a new allele, and the reverse process is backmutation. The frequency o/mutation per locus per generation (mutation rate) must be distinguished from mutant frequency, indicating simply the number of mutants in a population. Mutation in the broad sense involves also hereditary changes in chromosome number (polyploidy and aneuploidy) and chromosome structure, visible through the light microscope. The latter types are frequently called chromosomal aberrations. Arabidopsis, without further qualifications, in this context, will refer to Arabidopsis thaliana (L.) Heynh. in its diploid form (2n = 10). This species has three genomes, the nuclear, plastidic and the mitochondrial. Its nuclear genome (n = 5) is the smallest among higher plants (Leutweiler et al., 1984), containing about 0.7 - 1 x 108 bp, and redundancy is very low (Meyerowitz and Pruitt, 1985). The plastid genome is about the same size as that of the mcYority of higher plants, ca. 150 kb. The size of the mitochondrial genome is ca. 400 kb. Arabidopsis is an excellent tool for genetics and its critical features and known mutants have been reviewed (R&Iei , 1970, 1975a,b; Kranz, 1978; Meyerowitz and Pruitt, 1984; Meyerowitz, 1987, 1989; Estelle and Somerville, 1986; Bowman et al., 1988).
The study adressed 4 basic issues: (1) What are the substantive contents of human values? (2) Can we identify a comprehensive set of values? (3) To what extent is the meaning of particular values equivalent for different groups of people? (4) How are the relations among different values structured? These issues required resolution before the antecedents and consequences of value priorities, or cross-cultural differences in such priorities, could be studied effectively. Substantial progress has been made toward resolving each of these issues.
When in 1934, Robert BLEICHSTEINER published the Caucasian language specimina contained in the "travel book" of the 17th century Turkish writer Evliya Çelebi , he was struck by the amount of reliability he found in Evliya’s notations: "(Die Sprachproben) sind, von einzelnen Mißverständnissen abgesehen, und wenn man die falschen Punktierungen und Irrtümer der Kopisten abrechnet, außerordentlich gut, ja zuweilen mit einem gewissen phonetischen Geschick wiedergegeben, was der Auffassungsgabe und dem Eifer Evliyas ein hohes Zeugnis ausstellt. Man muß bedenken, wie schwer das arabische Alphabet, ohne weitere Unterscheidungszeichen, wie sie die islamischen Kaukasusvölker anwenden, die verwickelten, oft über 70 verschiedene Phoneme umfassenden Lautsysteme wiederzugeben imstande ist. Wenn trotzdem die Entzifferung der Sprachproben zum größten Teil geglückt ist, so muß man der ungewöhnlichen Begabung des türkischen Reisenden und Gelehrten schrankenlose Bewunderung zollen" (85). ...
The paper focuses on business negotiation in settings in which participants from different mothertongue backgrounds choose French, English andfor German as one of their languages of communication. A general scheme of the action-pattem of buying and selling will be sketched out which allows us to analyze specific Courses of verbal actions according ta their communicative functions within the negotiation process. In particular, the discourse of business communication is to be specified as a decision making process on the part of the buyer which is executed in a step-by-step order, and which is Open to the application of a bundle of the seller's strategies, tactics, and communicative techniques. In international negotiations, effects of unobserved miscommunication are, among others, far-stretched communicative circles, prolongation of negotiation time, non-functional explanations and several other repetitive structures. 1. Languages of trade and commerce - languages of communication 2. Communication in a Buy-Sell-Context is patterned 2.1. Entering the Pattern 2.2. The Main Phase 2.3. The Bidding Phase 2.4. The Specifc Conditions 2.5. Negotiating the Contract 3. The Central Point 3.1. The Buyer's Decision-Making Process 3.2 Decision-Making and Role-Playing 3.3. Intercultural Difference of the Decision-Making Process 4. Bridging the Buyer's Gap of Knowledge 5. The Language of Trade and Commerce 6. The Needs of Further Research: Data References
Crépin (1891) arranged 55 species of Rosa into 15 sections. Three of those sections contain taxa native to the British Isles, and members of several further sections have been reported as naturelized. In the discussion below, accepted names are shown in bold, while rejected names are given in italics.
The properties of nuclear matter are studied in the framework of quantum hadrodynamics. Assuming an ω-meson field, periodic in space, a self-consistent set of equations is derived in the mean-field approximation for the description of nucleons interacting via σ-meson and ω-meson fields. Solutions of these self-consistent equations have been found: The baryon density is constant in space, however, the baryon current density is periodic. This high density phase of nuclear matter can be produced by anisotropic external pressure, occurring, e.g., in relativistic heavy ion reactions. The self-consistent fields developing beyond the instability limit have a special screw symmetry. In the presence of such an ω field, the energy spectrum of the relativistic nucleons exhibits allowed and forbidden bands, similar to the energy spectrum of the electrons in solids.
We investigate the production of heavy quarks in continuum and bound states in nuclear collisions. Creation rates for free bb and tt quark pairs and for bottomonium and toponium in the ground state are computed at energies of the BNL Relativistic Heavy Ion Collider, CERN Large Hadron Collider (LHC), and Superconducting Super Collider. Central and peripheral heavy-ion collisions are discussed. For top-quark creation we assumed a mass range of 90≤mt≤250 GeV. The creation rate for top quarks in peripheral collisions is estimated to be by a factor 40 to 130 smaller compared with corresponding central collisions. For mt=130 GeV we calculated a creation rate of about 4760 top-quark pairs per day at the LHC (3.5 TeV/nucleon) for Pb-Pb collisions.
We discuss the multiplicity distribution of electron-positron pairs created in the strong electromagnetic fields of ultrarelativistic heavy-ion transits. Based on nonperturbative expressions for the N-pair creation amplitudes, the Poisson distribution is derived by neglecting interference terms. The source of unitarity violation is identified in the vacuum-to-vacuum amplitude, and a perturbative expression for the mean number of pairs is given.
Relativistic heavy ion collisions constitute a prolific source of hyperons: tens of hyperons per event are predicted at energies E≥10 GeV/nucleon, providing a scenario for the formation of metastable exotic multihypernuclear objects. They may exhibit exceptional properties: bound neutral (e.g., 4M2Λ2n, 10M2Λ8n, pure Λ droplets, 8Λ) and even negatively charged composites objects with positive baryon number (e.g., 4M2Σ-2n, 6M2Λ2Ξ-2n) could be formed in rare events. Such negative nuclei can easily be identified in a magnetic spectrometer. They could be considerably more abundant than antinuclei of the same A. We use the relativistic meson-baryon field theory—which gives an excellent description of normal nuclear and single-Λ hypernuclear properties—to calculate the rich spectrum of such exotic objects, their stability, and their structure. We also find solutions for a large variety of bound short-lived nuclei (e.g., 8M2Λ,2Σ-2p2n), which may decay strongly via formation of cascade (Ξ) particles. Multi-Ξ hypernuclei are also evaluated. A variety of potential candidates for such metastable exotic nuclei is presented. It turns out that the properties of such exotic multihypernuclear objects reveal quite similar features as the strangelet proposed as a unique signature for quark-gluon plasma formation in heavy ion collisions.
A quasiclassical Pauli potential is used to simulate the Fermi motion of nucleons in a molecular dynamical simulation of heavy ion collisions. The thermostatic properties of a Fermi gas with and without interactions are presented. The inclusion of this Pauli potential into the quantum molecular dynamics (QMD) approach yields a model with well defined fermionic ground states, which is therefore also able to give the excitation energies of the emitted fragments. The deexcitation mechanisms (particle evaporation and multifragmentation) of the new model are investigated. The dynamics of the QMD with Pauli potential is tested by a wide range of comparisons of calculated and experimental double-differential cross sections for inclusive p-induced reactions at incident energies of 80 to 160 MeV. Results at 256 and 800 MeV incident proton energy are presented as predictions for completed experiments which are as yet unpublished.
Stopping power and thermalization in relativistic heavy ion collisions is investigated employing the quantum molecular dynamics approach. For heavy systems stopping of the incoming nuclei is predicted, independent of the energy. The influence of the quantum effects and their increasing importance at low energies, is demonstrated by inspection of the mean free path of the nucleons and the n-n collision number. Classical models, which neglect these effects, overestimate the stopping and the thermalization as well as the collective flow and squeeze out. The sensitivity of the transverse and longitudinal momentum transfer to the in-medium cross section and to the pressure is investigated.
Experimental results are presented on the charge, velocity, and angular distributions of intermediate mass fragments (IMFs) for the reaction Fe+Au at bombarding energies of 50 and 100 MeV/nucleon. Results are compared to the quantum molecular dynamics (QMD) model and a modified QMD which includes a Pauli potential and follows the subsequent statistical decay of excited reaction products. The more complete model gives a good representation of the data and suggests that the major source of IMFs at large angles is due to multifragmentation of the target residue.
Strong correlations between baryon stopping in the projectile rapidity hemisphere and target excitation have been found in the light-ion-induced reactions at the BNL Alternating Gradient Synchrotron (AGS) (E814 group). Results in the framework of the relativistic molecular dynamics approach (RQMD) describe recent E814 data quite well. We discuss the RQMD results together with proton and pion data from the E802 group near midrapidity. They have raised the question of whether partial transparency could be seen in these experiments. The RQMD results indicate strong transverse baryon flow in central Si+Au collisions after the projectile has been stopped in the target.