641 research outputs found
Quaternary stratigraphy, landscape, and soils of the Hamilton Basin
The Hamilton Basin is a roughly oval shaped depression 80 km north to south and 40 km wide centered about Hamilton City (Fig. 1). The basin is surrounded by ranges up to 300 m high developed mainly in Mesozoic basement strata. The physiographic basin is essentially a fault bounded basement depression of Late Tertiary and Pleistocene age. Throughout the Quaternary this basin has been a receptacle of terrestrial sedimentation; the materials have derived mainly from extrabasin sources and principally the Central Volcanic Region to the southeast. In addition, materials have been derived from erosion of the bounding ranges, and Coromandel Peninsula. The last major depositional episode involved flood deposit s of the Taupo Pumice. The present landscape has evolved through several episodes of deposition and incision.
During the excursion it is intended to show the participants exposures of the major Quaternary units of basin infilling, and some aspects of the landscape and the soil pattern, within the environs of Hamilton City.
The standard geological reference covering the geology of Hamilton Basin is New Zealand Geological Survey Bulletin 88 (Kear & Schofield, 1978) . The surface features and soil pattern of the basin are succinctly covered by McCraw (1967) and Bruce (1979)
Alcohol: a cause of diabetes in Rhodesia
Forty-four per cent of newly-diagnosed Black male diabetic patients habitually drank more than 500 ml alcohol per week. This is a far higher proportion than in healthy men matched for age (6 - 12%), and suggests that the abuse of alcohol contributes to the development of diabetes in this population. In diabetic patients a high consumption of alcohol was found to be associated with liver damage, including cirrhosis, and also with iron overload, but not with insulinopenia or steatorrhoea. Twelve of the 98 newlydiagnosed diabetic patients also had cirrhosis, and 14 had a raised serum iron concentration or saturation.S. Afr. Med. J., 48, 1115 (1974)
Ages on weathered Plio-Pleistocene tephra sequences, western North Island, New Zealand
Using the zircon fission-track method, we have obtained five ages on members of two strongly-weathered silicic, Pliocene-Pleistocene tephra sequences, the Kauroa and Hamilton Ash formations, in western North Island, New Zealand. These are the first numerical ages to be obtained directly on these deposits. Of the Kauroa Ash sequence, member K1 (basal unit) was dated at 2.24 ± 0.29 Ma, confirming a previous age of c. 2.25 Ma obtained (via tephrochronology)from K/Ar ages on associated basalt lava. Members K2 and K3 gave indistinguishable ages between 1.68 ± 0.12 and 1.43 ± 0.17 Ma. Member K12, a correlative of Oparau Tephra and probably also Ongatiti Ignimbrite, was dated at 1.28 ± 0.11 Ma, consistent with an age of 1.23 ± 0.02 Ma obtained by various methods on Ongatiti Ignimbrite. Palaeomagnetic measurements indicated that members K13 to K15 (top unit, Waiterimu Ash) are aged between c. 1.2 Ma and 0.78 Ma. Possible sources of the Kauroa Ash Formation include younger volcanic centres in the southern Coromandel Volcanic Zone or older volcanic centres in the Taupo Volcanic Zone, or both. Of the Hamilton Ash sequence, the basal member Ohinewai Ash (HI) was dated at 0.38 ± 0.04 Ma. This age matches those obtained by various methods on Rangitawa Tephra of 0.34-0.35 Ma, supporting correlation with this Whakamaru-caldera derived deposit. The origin of the other Hamilton Ash beds is unknown but various younger volcanic centres in the Taupo Volcanic Zone are possible sources. The topmost member, Tikotiko Ash (H6-H7), is estimated to be aged between c. 0.18 and 0.08 Ma. Various silicic pyroclastic deposits documented in North Island and in marine cores may be co-eval with members of the Kauroa Ash and Hamilton Ash sequences on the basis of their age
Exploring high-end climate change scenarios for flood protection of the Netherlands
This international scientific assessment has been carried out at the request of the Dutch Delta Committee. The "Deltacommissie" requested that the assessment explore the high-end climate change scenarios for flood protection of the Netherlands. It is a state-of–the art scientific assessment of the upper bound values and longer term projections (for sea level rise up to 2200) of climate induced sea level rise, changing storm surge conditions and peak discharge of river Rhine. It comprises a review of recent studies, model projections and expert opinions of more than 20 leading climate scientists from different countries around the North Sea, Australia and the US
Hot String Soup
Above the Hagedorn energy density closed fundamental strings form a long
string phase. The dynamics of weakly interacting long strings is described by a
simple Boltzmann equation which can be solved explicitly for equilibrium
distributions. The average total number of long strings grows logarithmically
with total energy in the microcanonical ensemble. This is consistent with
calculations of the free single string density of states provided the
thermodynamic limit is carefully defined. If the theory contains open strings
the long string phase is suppressed.Comment: 13 pages, no figures, uses LaTex, some errors in equations have been
corrected, NSF-ITP-94-83, UCSBTH-94-3
A survey of partial differential equations in geometric design
YesComputer aided geometric design is an area
where the improvement of surface generation techniques
is an everlasting demand since faster and more accurate
geometric models are required. Traditional methods
for generating surfaces were initially mainly based
upon interpolation algorithms. Recently, partial differential
equations (PDE) were introduced as a valuable
tool for geometric modelling since they offer a number
of features from which these areas can benefit. This work
summarises the uses given to PDE surfaces as a surface
generation technique togethe
Using Top-Points as Interest Points for Image Matching
We consider the use of so-called top-points for object retrieval. These points are based on scale-space and catastrophe theory, and are invariant under gray value scaling and offset as well as scale-Euclidean transformations. The differential properties and noise characteristics of these points are mathematically well understood. It is possible to retrieve the exact location of a top-point from any coarse estimation through a closed-form vector equation which only depends on local derivatives in the estimated point. All these properties make top-points highly suitable as anchor points for invariant matching schemes. In a set of examples we show the excellent performance of top-points in an object retrievaltask
Statistical Theory of Spin Relaxation and Diffusion in Solids
A comprehensive theoretical description is given for the spin relaxation and
diffusion in solids. The formulation is made in a general
statistical-mechanical way. The method of the nonequilibrium statistical
operator (NSO) developed by D. N. Zubarev is employed to analyze a relaxation
dynamics of a spin subsystem. Perturbation of this subsystem in solids may
produce a nonequilibrium state which is then relaxed to an equilibrium state
due to the interaction between the particles or with a thermal bath (lattice).
The generalized kinetic equations were derived previously for a system weakly
coupled to a thermal bath to elucidate the nature of transport and relaxation
processes. In this paper, these results are used to describe the relaxation and
diffusion of nuclear spins in solids. The aim is to formulate a successive and
coherent microscopic description of the nuclear magnetic relaxation and
diffusion in solids. The nuclear spin-lattice relaxation is considered and the
Gorter relation is derived. As an example, a theory of spin diffusion of the
nuclear magnetic moment in dilute alloys (like Cu-Mn) is developed. It is shown
that due to the dipolar interaction between host nuclear spins and impurity
spins, a nonuniform distribution in the host nuclear spin system will occur and
consequently the macroscopic relaxation time will be strongly determined by the
spin diffusion. The explicit expressions for the relaxation time in certain
physically relevant cases are given.Comment: 41 pages, 119 Refs. Corrected typos, added reference
Tephrochronology of core PRAD 1-2 from the Adriatic Sea: insights into Italian explosive volcanism for the period 200–80 ka
Core PRAD 1-2, located on the western flank of the Mid-Adriatic Deep, was investigated for tephra content within the part of the sequence assigned on biostratigraphic and sapropel-layer stratigraphy to MIS 5 and 6 (ca. 80–200 ka BP). A total of 11 discrete tephra layers are identified, 8 visible and 3 cryptotephra layers. 235 geochemical measurements obtained from individual glass shards using WDS-EPMA enabled 8 of the 11 tephras to be correlated to known eruption events, 5 of which are represented in the Lago Grande di Monticchio (LGdM) regional tephra archive sequence. Three of these layers are recognised ultra-distally for the first time, extending their known distributions approximately 210 km further north. The results provide an independent basis for establishing an age-depth profile for the MIS 5–6 interval in the PRAD 1-2 marine record. This approach allowed age estimates to be interpolated for the tephra layers that could not be correlated to known events. It also provides an independent test of, and support for, the broad synchroneity of sapropel-equivalent (S-E) events in the Adriatic Sea with the better-developed sapropel layers of the eastern Mediterranean, proposed by Piva et al. (2008a)
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