An unexceptional scale     

Michele Ford 《Singapore journal of tropical geography》2008,29(2):130-132

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A Farey story: the pioneer geologist John Farey (1766–1826)     

Trevor D. Ford  Hugh S. Torrens† 《Geology Today》2001,17(2):59-68

John Farey was a pioneer British geologist whose work has been too long overlooked. His only major geological publication was concealed in what appears to be a local report on the agriculture and minerals of Derbyshire, commissioned by the Board of Agriculture and published in three volumes between 1811 and 1817. Farey also published an extraordinary amount in periodicals and prepared a remarkable series of geological maps and cross-sections which were never published, although a number of hand-drawn copies circulated and undoubtedly influenced the rise of stratigraphical geology.  相似文献   

Batse spectroscopy detector calibration     

D. Band  L. Ford  J. Matteson  J. P. Lestrade  B. Teegarden  B. Schaefer  T. Cline  M. Briggs  W. Paciesas  G. Pendleton  R. Austin  G. Fishman  C. Meegan  R. Wilson 《Experimental Astronomy》1992,2(5):307-330

We describe the channel-to-energy calibration of the Spectroscopy Detectors of the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (GRO). These detectors consist of NaI(Tl) crystals viewed by photomultiplier tubes whose output in turn is measured by a pulse height analyzer. The calibration of these detectors has been complicated by frequent gain changes and by nonlinearities specific to the BATSE detectors. Nonlinearities in the light output from the NaI crystal and in the pulse height analyzer are shifted relative to each other by changes in the gain of the photomultiplier tube. We present the analytical model which is the basis of our calibration methodology, and outline how the empirical coefficients in this approach were determined. We also describe the complications peculiar to the Spectroscopy Detectors, and how our understanding of the detectors' operation led us to a solution to these problems.  相似文献   

Organic carbon deliveries and their flow related dynamics in the Fitzroy estuary     

Ford P  Tillman P  Robson B  Webster IT 《Marine pollution bulletin》2005,51(1-4):119-127

The Fitzroy estuary (Queensland, Australia) receives large, but highly episodic, river flows from a catchment (144,000 km(2)) which has undergone major land clearing. Large quantities of suspended sediments, and particulate and dissolved organic carbon are delivered. At peak flows, delta(13)C (-21.7+/-0.8 per thousand) and C/N (14.8+/-1.3) of the suspended solids indicate that the particulate organic material entering the estuary is principally soil organic carbon. At the lower beginning flows the particulate organic matter comes from in-stream producers (delta(13)C=-26 per thousand). The DOC load is about 10 times the POC load. Using the inverse method, budgets for POC and DOC were constructed for high and low flows. Under high flows, only a small portion of the POC and DOC load is lost in the estuary. Under dry season (low flow) conditions the estuary is a sink for DOC, but remains a source of POC to the coastal waters.  相似文献   

The emerging marine economy of the Pacific: edited by Chennat Gopalakrishnan Ann Arbor Science,Boston, USA, £42.50 (Distributed in Britain by the Butterworth Group,Borough Green,Sevenoaks, Kent TN15 8PH,UK)     

Glyn Ford 《Marine Policy》1985,9(3):249-250

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BEWARE OF NEW GEOGRAPHIES     

Larry R. Ford 《The Professional geographer》1982,34(2):131-135

The effort to make the discipline appear relevant and useful raises the danger of allowing applied geography to become yet another “new” geography. Though we must encourage the development of a viable applied geography, we must simultaneously make much greater use of our existing traditions and literature if we are to thrive in the long run as an academic discipline. Without a heritage, we are vulnerable.  相似文献   

Estimating mortality in natural assemblages of oysters     

Susan E. Ford  Meagan J. Cummings  Eric N. Powell 《Estuaries and Coasts》2006,29(3):361-374

To evaluate methods for calculating mortality in bivalve molluscs, we analyzed historical data from dredge surveys of both planted and natural oyster (Crassostrea virginica) grounds in Delaware Bay to compare total box-count mortality estimates with those made by accumulating short-term mortality rates obtained from fresh boxes identified by shell condition and degree of fouling. Box-count and cumulative-mortality patterns and values agreed best on grounds with planted oysters, where a cohort with very few dead oysters was broadcast on previously cleaned bottom and was followed over time. This situation is analogous to an artificially created reef with oysters either deployed or naturally set on it. When deaths predominated in late summer and early autumn, the two estimates were similar throughout the following year; when mortality was greatest in spring or early summer, the estimates were similar only through autumn of the same year. Correspondence was much weaker on natural beds, where new individuals constantly recruited to the population and variable numbers of boxes were always present. Nevertheless, total box-count mortality estimates made during autumn stock surveys were significantly correlated with cumulative mortalities calculated for the preceding year. We also estimated disarticulation rates of artificially created boxes by deploying them at three seasons and eight sites in Delaware Bay. Disarticulation time depended on the length of exposure at summer temperatures, with the average time to 50% disarticulation for boxes deployed in spring and in summer being 225 and 345 days, respectively. Disarticulation rates increased with decreasing size, and increasing salinity and temperature. Finally, we compared total box-count and cumulative-mortality estimates with those made using the disarticulation data. Annual averages for the three methods were within 5 percentage points of each other. Our data indicate that total box-count mortality estimates from fall stock surveys can provide a reliable index to total mortality for the previous year, although it cannot describe the seasonal patterns obtainable using the cumulative-mortality method. *** DIRECT SUPPORT *** A02BY003 00003  相似文献   

Diffusion-creep modelling of fibrous pressure-shadows     

J.R. Berton  D.W. Durney  J. Wheeler  J.M. Ford 《Tectonophysics》2006,425(1-4):191-205

Grain-scale deformation of a bimineralic composite by normal-stress-driven grain-boundary diffusive mass-transfer has been modelled using diffusion-creep software that, for the first time, allows different diffusion coefficients for interphase boundaries and grain-boundaries as well as for different components. By selecting suitable coefficients we have obtained a fully coupled mechanical and mass-transfer numerical solution for the formation of fibrous pressure-shadows or strain fringes at the interface between a rigid object and a deforming rock matrix of different compositions. The model is two-dimensional and run in pure-shear velocity mode to a stretch ratio of 1.4. The first results are reported, which show dissolution and face-controlled antitaxial growth of a soluble, polycrystalline, calcite matrix at the interface with a circular and relatively insoluble pyrite object.The ratio of CaCO₃ diffusion along calcite–pyrite versus calcite–calcite boundaries strongly influences the extent of pressure-shadow growth and the pattern of strains in the matrix. A low ratio produces little growth, significant perturbation, and deflection of total-strain axes around the pyrite. An intermediate ratio produces appreciable growth, little perturbation, and near-parallel total-strain axes. A high ratio produces larger pressure-shadows, and total-strain axes that bend in towards the pyrite as if it were a weak object. Sliding and rotation of matrix grains are also affected.These results differ fundamentally from purely physical models of ductile flow around a rigid object and demonstrate the influence of interface diffusional properties on the resulting behaviour. In particular, assumptions such as perturbation of the flow by the object, deflection of external foliation around pre-deformational porphyroblasts and relationships of pressure-shadow strain to bulk strain may need to be re-examined in the light of this finding.  相似文献   

A geological model of London and the Thames Valley,southeast England     

S.J. Mathers  H.F. BurkeR.L. Terrington  S. ThorpeR.A. Dearden  J.P. WilliamsonJ.R. Ford 《Proceedings of the Geologists' Association. Geologists' Association》2014

Many geological survey organisations have started delivering digital geological models as part of their role. This article describes the British Geological Survey (BGS) model for London and the Thames Valley in southeast England. The model covers 4800 km² and extends to several hundred metres depth. It includes extensive spreads of Quaternary river terraces and alluvium of the Thames drainage system resting on faulted and folded Palaeogene and Cretaceous bedrock strata. The model extends to the base of the Jurassic sedimentary rocks.  相似文献