Fundamental reassessment of the taxonomy of five Normapolles pollen genera

National audienceDiagnoses of the Normapolles pollen genera Hungaropollis,Krutzschipollis, Longanulipollis, Oculopollis and Trudopollis and56 of their species are emended and many specimens illustrated inorder to provide a basis for more successful and consistent identificationthan has been possible hitherto. These taxa were recoveredfrom palynological preparations of selected samples from Late Cretaceousdeposits in Europe, southern Sweden and eastern USA.As indicated on an accompanying range chart the majority are encounteredin Santonian and/or Campanian deposits. Eleven of thespecies described have been transferred from other genera and aretherefore in new combinations, namely: Hungaropollis granulatus(Kedves et Herngreen), Longanulipollis coronatiformis (Góczánet Siegl-Farkas), L. orbicularis (Góczán), L. ornatus (Kedves etDiniz), L. parvoculus (Góczán), L. skarbyae (Kedves et Diniz),Oculopollis artifex (Weyland et Krieger), O. rector (Pflug), O.triceps (Skarby), Trudopollis cuneolis (Góczán et Siegl-Farkas),and T. spinulosus (Skarby). Six are new: Hungaropollis pinguis,Krutzschipollis cucullus, K. immanis, Longanulipollis amabilis, L.lobus and Oculopollis viriosus. Thirteen genera are regarded assynonyms of Hungaropollis (Aveiropollenites and Romeinipollenites),Longanulipollis (Coronatipollis, Intercalaripollis, Portaepollenitesand Verruoculopollis), Oculopollis (Druggipollenites, Pseudoculopollisand Semioculopollis) and Trudopollis (Cuneipollis,Felderipollenites, Hofkeripollenites and Kriegeripollenites) respectively.As a result of some of these nomenclatural changes 14 otherspecies are in new generic combinations but are not otherwise considered.Seven morphotypes are identified in open nomenclatureand four placed in comparison

Two Alternative Macro-Based Approaches to Model Telecommunication Traffic

(no abstract available)Series: Discussion Papers of the Institute for Economic Geography and GIScienc

Spatial Distribution of Pleistocene and Holocene Faunal Remains, South Block Excavations

The fossil remains of mammoth and other Pleistocene fauna found along and near the escarpment of the west shore of Lima Reservoir in Centennial Valley have been the subject of field investigations since the 1980s. Summaries or earlier studies conducted at the locality are presented in various published and unpublished sources including Albanese, Davis, and Hill (1995), Bump (1995), Davis and Batten (1996), Dundas (1989, 1990, 1996), Hill and Albanese (1996), and Hill, Davis, and Albanese (1995)

Re-examination of the palynological content of the Lower Cretaceous deposits of Angeac, Charente, south-west France::Age, palaeoenvironment and taxonomic determinations

International audienceFurther to the work published by Néraudeau et al. six years ago, palynological matter recovered from the lignitic bone bed of Angeac in Charente (south-west France) has been re-examined in order to provide more evidence of its age, the previous Hauterivian–Barremian interpretation being regarded as controversial. The samples come from four sedimentological units, An2–An5, which together yielded an assemblage of 34 species, taxonomically dominated by palaeoecologically significant lygodiaceous verrucate spores, including eight species attributable to the genus Concavissimisporites and three species of Trilobosporites. A few bisaccate pollen grains, including Vitreisporites pallidus, have been recovered, but the gymnospermous pollen spectrum is clearly dominated by the cheirolepidiaceous genus Classopollis, its abundance diminishing progressively upwards from units An4 to An2. The great abundance and diversity of verrucate forms, along with the presence of other spores typical of Lower Cretaceous deposits, such as Aequitriradites verrucosus, and the scarcity of specimens referable to Cicatricosisporites, render this assemblage most similar to those of the Hastings Group of southern England, and the Bückeberg Formation in north-western Germany. The time of deposition is, therefore, more likely to have been Berriasian–Valanginian rather than Hauterivian–Barremian, as previously stated. The associated small assemblage of megaspores is consistent with this determination. Except for Trilobosporites and Concavissimisporites, the use of several other genera commonly applied to Mesozoic verrucate spores, such as Converrucosisporites and Impardecispora, is considered unnecessary. To support this assertion, a Principal Components Analysis has been carried out on 120 verrucate spores from sedimentological units An2–4, taking into account ten morphological variables. The results show that specimens attributable to Trilobosporites are well be separated from the main cluster, which corresponds to Concavissimisporites, underlining the futility of using more than two genera for the species concerned

Closed-Cycle, Frequency-Stable CO2 Laser Technology

These proceedings contain a collection of papers and comments presented at a workshop on technology associated with long-duration closed-cycle operation of frequency-stable, pulsed carbon dioxide lasers. This workshop was held at the NASA Langley Research Center June 10 to 12, 1986. The workshop, jointly sponsored by the National Aeronautics and Space Administration (NASA) and the Royal Signals and Radar Establishment (RSRE), was attended by 63 engineers and scientists from the United States and the United Kingdom. During the 2 1/2 days of the workshop, a number of issues relating to obtaining frequency-stable operation and to the catalytic control of laser gas chemistry were discussed, and specific recommendations concerning future activities were drafted

Barriers to Communication: Reflections on Methodological Approaches

Series: Discussion Papers of the Institute for Economic Geography and GIScienc

Novel Ground-State Crystals with Controlled Vacancy Concentrations: From Kagom\'{e} to Honeycomb to Stripes

We introduce a one-parameter family, $0 \leq H \leq 1$, of pair potential functions with a single relative energy minimum that stabilize a range of vacancy-riddled crystals as ground states. The "quintic potential" is a short-ranged, nonnegative pair potential with a single local minimum of height $H$ at unit distance and vanishes cubically at a distance of \rt. We have developed this potential to produce ground states with the symmetry of the triangular lattice while favoring the presence of vacancies. After an exhaustive search using various optimization and simulation methods, we believe that we have determined the ground states for all pressures, densities, and $0 \leq H \leq 1$. For specific areas below 3\rt/2, the ground states of the "quintic potential" include high-density and low-density triangular lattices, kagom\'{e} and honeycomb crystals, and stripes. We find that these ground states are mechanically stable but are difficult to self-assemble in computer simulations without defects. For specific areas above 3\rt/2, these systems have a ground-state phase diagram that corresponds to hard disks with radius \rt. For the special case of H=0, a broad range of ground states is available. Analysis of this case suggests that among many ground states, a high-density triangular lattice, low-density triangular lattice, and striped phases have the highest entropy for certain densities. The simplicity of this potential makes it an attractive candidate for experimental realization with application to the development of novel colloidal crystals or photonic materials.Comment: 25 pages, 11 figure

The Network Megalopolis : A Creative and Sustainable Path for Urban Futures?

This short paper summarizes findings from some recent studies undertaken by the author and his colleagues concerning metropolitan development in the industrialized world. Three particular aspects are stressed : (1) The need to extend the way in which we analyze city systems - from the traditional perspective of centres within subnational hierarchies of settlments to the cosmopolitan perspective of urban nodes，corridors and hubs forming a complex system of interdependent cities feeding on various transnational networks. (2) The need to modify our lifecycle theories of urban development in order to cater for the dynamic synergies inherent in these networks，and the fact that collective stocks of knowledge reside in constellations of net-work cities rather than in any single centre alone. (3) The need to recognize the different speeds of urban adjustment processes，and the fact that because infrastructure is one of the slowest facets of development，it actually plays a fundamental role in controlling the nature and pace of other faster processes of adjustment

Noninvasive two-photon imaging reveals retinyl ester storage structures in the eye

Visual sensation in vertebrates is triggered when light strikes retinal photoreceptor cells causing photoisomerization of the rhodopsin chromophore 11-cis-retinal to all-trans-retinal. The regeneration of preillumination conditions of the photoreceptor cells requires formation of 11-cis-retinal in the adjacent retinal pigment epithelium (RPE). Using the intrinsic fluorescence of all-trans-retinyl esters, noninvasive two-photon microscopy revealed previously uncharacterized structures (6.9 ± 1.1 μm in length and 0.8 ± 0.2 μm in diameter) distinct from other cellular organelles, termed the retinyl ester storage particles (RESTs), or retinosomes. These structures form autonomous all-trans-retinyl ester-rich intracellular compartments distinct from other organelles and colocalize with adipose differentiation-related protein. As demonstrated by in vivo experiments using wild-type mice, the RESTs participate in 11-cis-retinal formation. RESTs accumulate in Rpe65 (−/−) mice incapable of carrying out the enzymatic isomerization, and correspondingly, are absent in the eyes of Lrat (−/−) mice deficient in retinyl ester synthesis. These results indicate that RESTs located close to the RPE plasma membrane are essential components in 11-cis-retinal production