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Institute
Book Review: Species in the genus Spermophagus are found in all of the Old World regions except Australia. Prior to this fine monograph, the taxonomy was a hodgepodge of local faunal treatments and single species descriptions with few usable keys or illustrations. Now we have available keys to 90 species with full descriptions, geographical distributions, and excellent illustrations of dorsal habitus, male genitalia, and many of the female genital valves.
The annulatipes group of the genus Forcipomyia Meigen, subgenus Lepidohelea Kieffer, is represented in the Western Hemisphere by 12 species. Keys are presented for their identification, and to distinguish them from other groups of the subgenus Lepidohelea. The three previously known species, annulatipes Macfie, brasiliensis Macfie, and kuanoskeles Macfie, from southern Brazil, as well as the following nine new species, are described and illustrated: bahiensis, basifemoralis, bifida, convexipenis, euthystyla, gravesi, herediae, hobbsi, and weemsi.
The following new species are described: Nyctonympha andersoni, sp. n., and N. howdenarum, sp. n., both from Colombia; N. genieri, sp. n., from Ecuador; N. taeniata, sp. n., from Trinidad; Falsamblesthis microps, sp. n., from Venezuela; Bactriola circundata, sp. n., from Brazil (Rio de Janeiro); B. maculata, sp. n., from Venezuela and Ecuador; and B. falsa, sp. n., from Brazil (Minas Gerais to Rio Grande do Sul). A redescription of Bactriola vittulata Bates, 1886, herein designated as the type species of the genus, is provided. Accurate data on the occurrence of Saepiseuthes chilensis Thomson, 1868, in Chile are given. Keys to the species of Bactriola Bates, 1886 and Nyctonympha Thomson, 1868 are added.
Twenty nine species of Delphacidae are recorded from the Yukon Territory, Canada, two additional ones from an adjacent region of Northwest Territories, and one species from coastal Alaska. Two new genera are described: Aschedelphax Wilson and Yukonodelphax Wilson. Six new species are described: Aschedelphax hochae Wilson, Delphacodes anufrievi Wilson, D. emeljanovi Wilson, Javesella lla Wilson, Nothodelphax glacia Wilson, and Yukonodelphax kendallae Wilson. Aschedelphax coloradensis (Beamer), Javesella kilmani (Van Duzee), Yukonodelphax pediforma (Beamer) and Y. stramineosa (Beamer) are new combinations. Kusnezoviella matisi Anufriev and Emeljanov is a junior synonym of K. macleani Wilson and Delphacodes hyalina Beamer is a junior synonym of Nothodelphax albocarinata (Stil). Of the 32 species included in the study, 18 have a Holarctic distribution - 10 of these are amphi-Beringian. The remaining 14 species are restricted to the Nearctic, 5 of these are recorded only from the Yukon and Northwest Territories.
Only five species of Bruchidae have been recorded from the Dominican Republic D.R) per se although records exist for “Hispaniola” and Haiti. Collections made during a recent trip (1992) by R. Turnbow and M.C. Thomas have added data for five additional species, one of which is a new West Indian record whereas the other three are range extensions of species previously known from the West Indies. Geographical ranges for each species are briefly indicated.
The following subgenera of Apion Herbst are elevated to generic status: Bothryopteron Wagner (type species: Apion grallarium Sharp); Coelocephiilapion Wagner (type species: Apion bryanti Wagner); Coelopterapion Wagner (type species: Apion testaceum Wagner); Fallapion Kissinger (type species: Apien impunctistriatum Smith); and Stenapion Wagner (type Species: Apion constricticolle Sharp). Twelve areas of apionid rostral sulci and carinae are defined and illustrated. Six new species of Coelooephalapien are described: four similar to C. bryanti, (Wagner): Jumentum (panama and Honduras), kektaon (Belize), pelor (Panama), and schema (panama); and two similar to C. spretissimum (Sharp): adhocum (Mexico) and pigrae (Venezuela). C. pilirostre (Wagner), near bryanti, is redescribed from Mexico and Honduras with neotype designation.
Affinities, diagnoses, and descriptions are provided for two new species of Plusiotis: P. spectabilis from an unknown locality in Central America and P. dianae from Veracruz state in Mexico. Plusiotis spectabilis is described from a single female and is the largest species in the genus (41 mm in length).
A new status is proposed for the genera Glabromyzus Richards, 1960 and Juncomyzus Hille Ris Lambers, 1965, which are now treated as subgenera of Carolinaia Wilson, 1911. The relationship between Carolinaia and Utamphorophoro Knowlton, 1947 is discussed. The new name C. (C.) tissoti is given for Carolinaia rhois Tissot, 1928 nec rhois Monell, 1879. The species known as Juncomyzus rhois (Takahashi, 1924) becomes C. (J.) japonica (Takahashi, 1961). The oviparous female of C. (G.) schlingeri, C. (J.) japonica, and C. (J.) nigra are described as well as the alate viviparous female and the male of the last species. Four keys are given for the apterous and alate living on Rhus and on Monocotyledones plants. The following 4 new species are described: C. (C.) floridensis, from USA, C. (G.) quadnaui from Canada, C. (G.) corazonensis and C. (C.) setariae both from Mexico. The host plants, life cycle and distribution of the 17 species of Carolinaia are discussed.
An undescribed genus and species of flightless longhorned beetle, Apteralcidion lupierrei new genus, new species, in the subfamily Lamiinae, has been collected from giant thistle, Cirsium subcoriaccum, at high elevations in Costa Rica and Panama. This new taxon appears most-closely related to genera in the tribe Acanthocini.
One hundred forty-five species of caddisflies representing 15 families and 46 genera are reported from Oklahoma. Thirty-nine species are new state records. Families having the greatest species richness were Hydroptilidae (44 species), Leptoceridae (31 species), Hydropsychidae (26 species), and Polycentropodidae (13 species).
Book Review: A comprehensive treatment of the ecology of aquatic insects in one place is needed for both students and researchers. Professor Ward is doing this in two volumes. The first volume covers the biology and habitats, as indicated in the subtitle, of the 13 insect orders that are either entirely aquatic at some stage, or those with some members aquatic at some stage. The second volume will be devoted entirely to the feeding ecology of these aquatic species.
Specific Alaskan and Canadian localities are recorded for the chilopod Scolopocryptops sexspinosus (Say) (Cryptopidae), the only indigenous Nearctic scolopendromorph species occurring north of the lower 48 states. It occurs west of the crest of the Coast Range in British Columbia, extending northward to the southernmost islands of Alaska, and is recorded for the first time from eastern Canada, from Niagara Gorge, Ontario. Reports of S. rubiginosus Koch from southern Alaska are based on a misidentification of S. sexspinosus, and records from the north-central United States are too distant from the international border for it to be plausible for Manitoba and western Ontario. This centipede does not occur along the Pacific Coast and is improbable for any other part of Canada.
Vincent Golia, Delray Beach, Florida, collected a single female specimen of the tamarind seed beetle, Caryedon serratus, in an orange grove near Homestead. This is the first record of this bruchid for continental United States although the species is recorded from the Hawaiian Islands, and is often intercepted during port inspections.
New records of the xystodesmid diplopod Stenodesmus tuobitus (Chamberlin) extend its range and those of the family and suborder Chelodesmidea into southwestern New Mexico, west of the Rio Grande. They confirm that it inhabits arid juniper environments at relatively low elevations as well as moist deciduous fir forests at high elevations, thereby lending credence to past records from the former habitat in Lincoln County. Discovery of the milliped in neighboring mountain ranges to the north and west is now likely, with the distant possibility that it may occur in eastern Arizona.
Ommatius fimbriatus and O. subtus are based upon four specimens embedded in Dominican amber from the El Mamey Formation in the Dominican Republic. The amber is from the Lower Oligocene - Upper Eocene, originating between 25 and 40 million years ago. The specimens are the first reported fossils of Ommatius. Both species are described and compared with modern species. Significant characters are illustrated and/or photographed.
The following species of Meloidae are recorded, together with notes on adult seasonal distribution and food plants, from the northwestern Argentine province of Salta: Protomeloe wagneri, Spastica sphaerodera, Acrolytta colon, Pyrota homcioi, P. signata, P. vittigera, P. wagneri, Pseudopyrota riojanensis, Wagneronota aratae, Pseudomeloe andensis, P. gracilior, P. ogloblini, Epicauta atomaria, E. bruchi, E. excavata, E. floydwerneri, E. fourcadei, E. fulvicornis, E. grammica, E. griseonigra, E. leopardina, E. lizeri, E. monachica, E. nigripes Borchmann (=E. langei Borchmann, syn. nov.), E. pluvialis, E. rosiilloi, E. rubella, E. rutilifirons, E. talpa, E. tristis, E. zebra, Tetraonyx brunnescens, T. kirschi, T. lampyroides, T. propinquu, T. sericea, Cissites maculata, Nemognatha coeruleipennis, N. nigronotata, N. nigrotarsata, N. subparallela, N. weiseri Pic (st. nov.), Pseudozonitis impressithorax (Pic) (comb. nov.). Eleven of the species are recorded from the province for the first time.
Ästhetische Modernisierung in der DDR-Literatur : zu Texten Volker Brauns aus den achtziger Jahren
(1992)
Angesichts der Stagnation bzw. des Verfalls der realsozialistischen Gesellschaft und der Erosion ihrer Ideologie sowie ihrer Literaturprogrammatik bricht der Autor [Volker Braun in den frühen achziger Jahren] mit der Monosemietradition des Offizial-Diskurses (Dogmatik des Marxismus-Leninismus, Modus der autoritativen Geltung). Dieser Bruch ergibt sich aus seiner neuen poetischen Konzeption, in der er Literatur radikal auf Subjektivität fundiert und das Konzept einer polyphonen Diskursivität entwickelt als Grundlage und Rahmen der literarischen Kommunikation. Von dieser neuen poetischen Konzeption aus, die Braun in seinem Essay "Rimbaud. Ein Psalm der Aktualität" skizziert und die mit der literarischen Praxis der frühachtziger Jahre korrespondiert, erschließen sich die Texte aus dieser Periode (und vice versa). Im folgenden untersuche ich Brauns programmatisches Gedicht "Das innerste Afrika" als Beispiel für sein Neues Sprechen.
A brief account of the present state of weevil taxonomy is followed by a detailed study of certain structures used in their classification, namely the venter, abdominal tergites, sternite 8 of the male, apex of the hind tibia and deciduous mandibular processes. A key to some 50 families and subfamilies of Curculionoidea is followed by a list of family-group taxa. The following changes are made: Brachyceridae, Erirhinidae. Cryptolnryngidae und Raymondionymidae are promoted to family rank from Curculiollidne; Antliarhininae is demoted to a subfamily of Brentidae, and Allocoryninae to a subfamily of Oxycorynidne; Coptonotini is demoted to a tribe of Curculionidue Scolytinae; Carinae, sufam. n. is erected for Car Blackburn (genus incertae sedis) in Belidae; Dinomor'phini is demoted to a tribe of Molytinae and Brachyccropsidinae is revived from synonymy with Dinomorphinae (Curclliionidae); Urachyderini, Eremnini, Otiorhynchini and Sitonini are demoted to tribes of Entiminue; Desmidophorinae is transferred from Brentidae to Brachyccridae, Ocladiini is promoted to a tribe of Desmidophorinae (from Curculionidae-Cryptorhynchinae); Campyloseelini (including Phaenomerina) is transferred from Rhynchophoridae to Curculionidae-Zygopinae; Carphodicticinae is promoted to subfamily rank and transferred from Curculionidae-Scolytinae to Platypodidae; Perieges; Schönherr is transferred from Curculionidae-Thecesterninae to Cryptoiaryngidae and Agriochaeta Pascoe from Cryptorhynchinae to Hyperinae (Curculionidae); Schadlarius Wood and Mecopelmus Blackman are transferred from Coptonotidae to Platypodidae.
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.
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.
Aus Kostengründen delegieren immer mehr Verlage das Erstellen von Druckvorlagen an DTP-Büros oder direkt an die Autoren. Doch mit den wegrationalisierten Schriftsetzern bleibt oft auch das typografische Know-how auf der Strecke. Insbesondere wissenschaftliche Publikationen sind wegen ihrer niedrigen Auflage von dieser Entwicklung betroffen. Die Gewohnheiten der Schreibmaschinen-Ära schlagen – meist unbemerkt von den satzunerfahrenen Produzenten – auf das Endprodukt durch. In einer dreiteiligen Serie gibt PAGE-Autor Peter Matussek praktische Hinweise zur Gestaltung wissenschaftlicher Publikationen für Nichtprofis.
Lesen und lesen lassen
(1992)
Mit dem Kürzel ICR (intelligent character recognition) will die Branche der Lesemaschinenhersteller signalisieren, daß sie die Legasthenieprobleme des herkömmlichen OCR (optisal character recognition) überwunden hat. Doch wie intelligent ist die neue Technik wirklich? Macht sie das mühselige Korrekturlesen überflüssig? In welchem Verhältnis steht der Aufwand zum Nutzen?
Zu den stupenden Erscheinungen der Naturwissenschaften heute gehört es, daß sie – wie durch Fieberanfälle – an ihren verschiedenen Fronten immer wieder von der Antike heimgesucht werden. Vermutlich überrascht dies weniger Philosophen als die Naturwissenschaftler selbst, die seit Galilei sich im Bewußtsein ihrer Überlegenheit von antiken naturphilosophischen Traditionen abgekehrt haben. Unterdessen gehört es fast zum Rhythmus wissenschaftlicher Reformen, daß diese im Namen des Alten erfolgen. Infolge der überbordenden Destruktionspotentiale moderner Technik wird die regeneratio der Wissenschaft allzu oft als conservatio der noch eben faßbaren Reste verlorener Traditionen gesucht. Ein gutes Beispiel dafür ist die Karriere der Gaia-Hypothese, die seit ihrer Kreation durch den Biosphären-Forscher James Lovelock (1979) und die Mikrobiologin Lynn Margulis (1986) in den USA einen ebenso umstrittenen wie unwiderstehlichen Aufschwung genommen hat. ...
Dieser Aufsatz möchte dem Deutschunterricht nicht noch einen weiteren Stoff - die latein-amerikanische Literatur - hinzufügen, um damit eine beliebig erweiterbare >Konkurrenz der Texte< zu eröffnen. Vielmehr wird lateinamerikanische Literatur für den Deutschunterricht vorgeschlagen und in Beispielen vorgestellt, weil sie besonders geeignet erscheint, im Zeitalter eines überall spürbaren Kulturwandels den Deutschunterricht zum Ort bewußter Auseinandersetzung mit >Kultur< zu machen. In den 20er Jahren schon wurde in einer Epoche ähnlich tiefgreifender kultureller Krisen über Deutschunterricht als >Kulturkunde< diskutiert. Damals lief die Absicht von Germanisten und Lehrplanautoren aber in der Hauptsache hinaus auf eine Festigung des Bewußtseins nationaler >deutscher Kultur<, auf eine Abschließung des >deutschen Wesens< nach außen. Die >Erziehung zum bewußten Deutschtum< gipfelte in der Formulierung des preußischen Ministerialrats im Kultusministerium, Hans Richert, aus dem Jahr 1924: >Im deutschen Unterricht sollen die Schüler lernen, deutsch zu reden und zu schreiben, deutsch zu fühlen, zu denken und zu wollen.<
Nichts scheint besser geeignet, um sich den Eurozentrismus, den kolonialen Blick abzugewöhnen, als die Beschäftigung mit lateinamerikanischer Literatur. Denn diese Literatur will anders sein, sie definiert sich widersprüchlich und provokativ als eine fremde, nicht-europäische Literatur. Die selbstgewählten Markenzeichen heißen: >realísmo mágico< und >real maravilloso< [...] Das Werk von Gabriel García Márquez, des vierten unter den fünf lateinamerikanischen Nobelpreisträgern, und des gegenwärtig weltweit erfolgreichsten lateinamerikanischen Autors scheint mit seiner >tropischen Phantasie<, seinem >eigenen Schwerkraftgesetz< ein besonders gutes Beispiel der ganz elementaren exotischen Phantasie zu sein.
Kunibert steht am Anfang der Kölner Kirchengeschichte des Mittelalters: Mit ihm beginnt jene lange Reihe von Bischöfen und Erzbischöfen, die auch am Königshof und im Reich von Bedeutung waren. Er band Stadt und Bistum in das regnum Francorum ein, er entwickelte weitausgreifende missionarisch-politische Aktivitäten, von denen heute noch seine Grabkirche am Rhein Zeugnis ablegt. Allein, schon seine ungesicherten Lebensdaten deuten an, daß jene Zeit zu den quellenärmsten Epochen der europäischen Geschichte gehört. Vieles läßt sich wohl nie mehr dem Dunkel entreißen, vieles läßt sich nur noch vermutend erschließen. Der Versuch, »Leben und Werk« nachzuzeichnen und zu würdigen, muß mithin zwangsläufig ein Versuch bleiben.
Nachrufe auf Theodor Schieffer (11.VII.1910 – 9.IV.1992): Mit Theodor Schieffer, der am 9. April 1992 in seiner Heimatstadt Bad Godesberg starb, ist ein bedeutender Mediävist dahingegangen, dessen Lebenslauf und wissenschaftliches Wirken mit Mainz und dem Rheinland eng verbunden waren: An der neugegründeten Johannes Gutenberg-Universität wirkte er von 1946 bis 1954, der Gesellschaft für mittelrheinische Kirchengeschichte stand er von 1952 bis 1955 als Präsident vor, und in vielen seiner Publikationen spielt dieser Raum eine gewichtige Rolle. ...
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.
Beitrag zur Kenntnis der Wasserinsektenfauna Nordwest-Hessens : 1. Köcherfliegen (Trichoptera)
(1992)
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.