Postcranial evidence for the evolution of the Black Wildebeest, Connochaetes gnou: an exploratory study

Black wildebeest fossils from the interior of South Africa and the Cape coastal zone are compared to modern specimens in order to trace the pattern of morphological change and the distribution of the species through time. Measurements taken on selected postcranial skeletal elements, i.e. the axis and metapodials, suggest that the evolution of the black wildebeest was marked by a general reduction in body size. It appears that the evolution of Connochaetes gnou from a blue wildebeest-like (C. taurinus) ancestor is best documented in areas to the south of the Vaal River. Although the geographic range of the two temporal subspecies of C. gnou (C. gnou laticornutus and C. gnou antiquus) included the Cape ecozone, the reduction in body size appears to have beeen accelerated in the Cape coastal zone where in the Last Glacial sensu lato there was a regionally distinct population. This population, of smaller body size than extant populations, became extinct at the end of the Last Glacial with the onset of higher sea levels.National Museum, Bloemfontei

Bathymetric terrain model of the Atlantic margin for marine geological investigations.

Bathymetric terrain models of seafloor morphology are an important component of marine geological investigations. Advances in acquisition and processing technologies of bathymetric data have facilitated the creation of high-resolution bathymetric surfaces that approach the resolution of similar surfaces available for onshore investigations. These bathymetric terrain models provide a detailed representation of the Earth’s subaqueous surface and, when combined with other geophysical and geological datasets, allow for interpretation of modern and ancient geological processes. The purpose of the bathymetric terrain model presented in this report is to provide a high-quality bathymetric surface of the Atlantic margin of the United States that can be used to augment current and future marine geological investigations. The input data for this bathymetric terrain model, covering almost 305,000 square kilometers, were acquired by several sources, including the U.S. Geological Survey, the National Oceanic and Atmospheric Administration National Geophysical Data Center and the Ocean Exploration Program, the University of New Hampshire, and the Woods Hole Oceanographic Institution. These data have been edited using hydrographic data processing software to maximize the quality, usability, and cartographic presentation of the combined terrain model

Hybrid wildebeest (Artiodactyla:Bovidae) provide further evidence for shared signatures of admixture in mammalian crania

The genus Connochaetes, Lichtenstein, 1814, contains two extant species, the blue wildebeest (C. taurinus, Burchell, 1823) and the black wildebeest (C. gnou, Zimmermann, 1780). In recent years, forced sympatry in confined areas within South Africa has led to interbreeding between these taxa and to fertile hybrid offspring. Here we report on a series of cranial characteristics of a hybrid wildebeest population culled at Spioenkop Dam Nature Reserve, KwaZulu-Natal, South Africa. Dental, sutural and horn morphological anomalies occur at high frequency within these animals. Similar cranial morphological anomalies have been shown in other mammalian hybrids and this study provides further evidence that such anomalies may characterise hybridisation more broadly across phylogenetically divergent mammalian groups, although the anomalies appear to differ in their expression across taxa. An increased ability to identify hybrids may also have important applications in the conservation of the endemic black wildebeest

Hybrid wildebeest (Artiodactyla:Bovidae) provide further evidence for shared signatures of admixture in mammalian crania

The genus Connochaetes, Lichtenstein, 1814, contains two extant species, the blue wildebeest (C. taurinus, Burchell, 1823) and the black wildebeest (C. gnou, Zimmermann, 1780). In recent years, forced sympatry in confined areas within South Africa has led to interbreeding between these taxa and to fertile hybrid offspring. Here we report on a series of cranial characteristics of a hybrid wildebeest population culled at Spioenkop Dam Nature Reserve, KwaZulu-Natal, South Africa. Dental, sutural and horn morphological anomalies occur at high frequency within these animals. Similar cranial morphological anomalies have been shown in other mammalian hybrids and this study provides further evidence that such anomalies may characterise hybridisation more broadly across phylogenetically divergent mammalian groups, although the anomalies appear to differ in their expression across taxa. An increased ability to identify hybrids may also have important applications in the conservation of the endemic black wildebeest

U.S. GLOBEC Georges Bank long-term moored program : part 1 - mooring configuration

As part of the U.S. GLOBEC Northwest Atlantic/Georges Bank program, moorings were deployed on Georges Bank as part of the broad-scale survey component to help measure the temporal variability of both physical and biological characteristics on the Bank. The array consisted of a primary mooring site on the Southern Flank which was maintained for the full 5-year duration of the field program, plus secondary moorings, with fewer sensors and of shorter duration, in the well-mixed water on the Crest and in the cod/haddock spawning region on the Northeast Peak. Temperature and conductivity (salinity) were measured at 5-m intervals, ADCP velocity profiles were obtained with 1-m vertical resolution, and bio-optical packages (measuring fluorescence, optical transmission and photosynthetically active radiation) were deployed at 10-m and 40-m depths. Bottom pressure was measured at the Southern Flank site. The buoy design, sensors and mooring configuration is presented and discussed below, and the data obtained is presented and discussed in an accompanying reports “U.S. GLOBEC Georges Bank Long-Term Moored Program: Part 2 – Yearly Data Summary and Report,” and “U.S. GLOBEC Georges Bank Long-Term Moored Program: Part 3 – Data Summary.”Funding was provided by the National Science Foundation under grant numbers OCE-93-13670, OCE-96-32348, OCE98-06379, OCE-98-06445 and OCE-02-27679

Palaeontology and geological context of a Middle Pleistocene faunal assemblage from the Gladysvale Cave, South Africa

Palaeontological and geological research at the Gladysvale Cave during the last decade has concentrated on de-roofed deposits located outside the Main Chamber. This area has been termed the Gladysvale External Deposit (GVED) and consists of fossil-rich calcified and decalcified sediments. Here we report on the recent analysis of both the faunal material and the geological context of this deposit. The faunal assemblage, excavated from the decalcified sediments contains 29 mammal species including taxa rare or absent in the Witwatersrand Plio-Pleistocene fossil record (e.g. Pelorovis and Kobus leche). Carnivores and porcupines are identified as accumulating agents of the bones. No new hominin findings can be reported from this deposit, and no cultural remains have been recovered. Geologically the calcified and decalcified breccias represent part of a large talus cone that is relatively unexposed. Uniquely for a cave fill in the Witwatersrand hominin-bearing sites, the sediments are horizontally stratified and form a number of flowstone bound sequences. The dating of the in situ cemented sediments is based on electron spin resonance (ESR) and palaeomagnetism. Recent results indicate that the deposits are of Middle-Pleistocene age.Palaeo-Anthropology Scientific Trust; French Embassy in South Africa; Co-operation and Cultural Service; National Geographic Society; John Nash and family; DACEL; University of the Witwatersrand Research Office and School of Geosciences; World Heritage Site Committee; SAHRA; Swiss National Science Foundation; NSF Grants ILl 9151111 and SBR 989628

Principal forms X^2 + nY^2 representing many integers

In 1966, Shanks and Schmid investigated the asymptotic behavior of the number of positive integers less than or equal to x which are represented by the quadratic form X^2+nY^2. Based on some numerical computations, they observed that the constant occurring in the main term appears to be the largest for n=2. In this paper, we prove that in fact this constant is unbounded as n runs through positive integers with a fixed number of prime divisors.Comment: 10 pages, title has been changed, Sections 2 and 3 are new, to appear in Abh. Math. Sem. Univ. Hambur

Vacua of M-theory and string theory

We argue that supersymmetric higher-dimension operators in the effective actions of M-theory and IIB string theory do not affect the maximally supersymmetric vacua: $adS_4\times S^7$ and $adS_7\times S^4$ in M-theory and $adS_5\times S^5$ in IIB string theory. All these vacua are described in superspace by a fixed point with all components of supertorsion and supercurvature being supercovariantly constant. This follows from 32 unbroken supersymmetries and allows us to prove that such vacua are exact.Comment: 16 pages, late

Quantising Gravity Using Physical States of a Superstring

A symmetric zero mass tensor of rank two is constructed using the superstring modes of excitation which satisfies the physical state constraints of a superstring. These states have one to one correspondence with quantised operators and are shown to be the absorption and emission quanta of the Minkowski space Lorentz tensors using the Gupta-Bleuler method of quantisation. The principle of equivalence makes the tensor identical to the metric tensor at any arbitrary space-time point. The propagator for the quantised field is deduced. The gravitational interaction is switched on by going over from ordinary derivatives to coderivatives.The Riemann-Christoffel affine connections are calculated and the weak field Ricci tensor $R^{0}_{\mu \nu}$ is shown to vanish. The interaction part $R^{int}_{\mu \nu}$ is found out and the exact $R_{\mu \nu}$ of theory of gravity is expressed in terms of the quantised metric. The quantum mechanical self energy of the gravitational field, in vacuum, is shown to vanish. It is suggested that quantum gravity may be renormalisable by the use of the physical ground states of the superstring theory.Comment: 14 page