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991.
Three coins of the Khotan horse, or Sino‐Kharosthi, style from Xinjiang province of China were recently obtained from a coin dealer. Because the archaeological context of these coins remains unknown, we conducted chemical and stylistic analyses to help determine their authenticity. Energy dispersive X‐ray (EDX) and wavelength dispersive X‐ray (WDX or microprobe) measurements indicate that they are red (pure) copper and bronze coins, with one coin containing 4.2% Ag. Metal content and the presence of secondary minerals formed through weathering indicate that these are authentic ancient coins that were buried in a dry environment. All three coins bear Chinese characters; one shows Kharosthi, and two display Brahmi, a popular language in Khotan from A.D. 260 to 282. This indicates that the Sino‐Brahmi coins were made slightly later than the Sino‐Kharosthi coins, which were made before A.D. 260. These specimens represent the first Sino‐Brahmi coin and 20‐zhu coin ever reported in the literature. © 2011 Wiley Periodicals, Inc.  相似文献   
992.
The catchability of western rock lobsters (Panulirus cygnus) during the spawning season (October and November) may be affected by their reproductive state. In this study, movement and food consumption of males and females of different reproductive states held in laboratory tanks were measured as proxies for catchability. Density of lobsters was found to influence both movement and food consumption. Solitary animals and, to a lesser extent, two lobsters per tank, were more sedentary and consumed significantly less food than animals at a density of three or four specimens per tank. Tests using three animals per tank confirmed that mature, unmated, and ovigerous females carrying early stage eggs moved more frequently away from their shelters than males or females carrying late stage eggs (P < 0.0001, d.f. = 3). Further, unmated females and females with early stage eggs recorded significantly higher food consumption (P < 0.0061, d.f. = 3) compared with males or females carrying late stage eggs. The greater time spent away from shelter and also food consumption make unmated females and females with early stage eggs likely to be more catchable than males or females with late stage eggs. As catchability is commonly used to obtain population estimates from survey data, these results have implications for surveys which use catch rates of breeding animals as indicators of egg production.  相似文献   
993.
994.
Calibration chamber tests were conducted on open‐ended model piles driven into dried siliceous sands with different soil conditions in order to clarify the effect of soil conditions on load transfer mechanism in the soil plug. The model pile used in the test series was devised so that the bearing capacity of an open‐ended pile could be measured as three components: outside shaft resistance, plug resistance, and tip resistance. Under the assumption that the unit shaft resistance due to pile‐soil plug interaction varies linearly near the pile tip, the plug resistance was estimated. The plug capacity, which was defined as the plug resistance at ultimate condition, is mainly dependent on the ambient lateral pressure and relative density. The length of wedged plug that transfers the load decreases with the decrease of relative density, but it is independent of the ambient pressure and penetration depth. Under several assumptions, the value of earth pressure coefficient in the soil plug can be calculated. It gradually reduces with increase in the longitudinal distance from the pile tip. At the bottom of the soil plug, it tends to decrease with increase in the penetration depth and relative density, and to increase with the increase of ambient pressure. This may be attributed to (1) the decrease of friction angle as a result of increase in the effective vertical stress, (2) the difference in the dilation degree of the soil plug during driving with ambient pressures, and (3) the difference in compaction degree of soil plug during driving with relative densities. Based on the test results, an empirical equation was suggested to compute the earth pressure coefficient to be used in the calculation of plug capacity using one‐dimensional analysis, and it produces proper plug capacities for all soil conditions.  相似文献   
995.
996.
Abstract

Vertical variations of geotechnical properties in the uppermost sediment layers characterize the main sedimentary processes acting on the construction and destruction of progressive‐type continental slopes. In the Gulf of Lions, the original thicknesses and distribution of the uppermost sedimentary layers of the continental slope and rise, which consist of Holocene muds overlying Pleistocene muds, have been greatly modified by erosion and several kinds of slope failure processes. Each process is typified through sets of geotechnical properties measured in the eroded or slumped sections and in the associated sediment accumulations.

In slump scars, the water‐rich Holocene muds lie on fine, overconsolidated, Pleistocene muds with high plasticity and low shear strength. In bottom current‐eroded slopes, where modern sedimentation is extremely reduced, the Pleistocene muds frequently outcrop and may sometimes be overlain by a very thin layer of Holocene muds. The Pleistocene muds of eroded slopes are overconsolidated and more silty and less plastic than the Pleistocene muds from slopes affected by slope failure, their shear strength being 10 times greater.

Deposits at the toe of slumps are very often formed by several superposed three‐layer units (triplets of interstratified Holocene, transitional, and Pleistocene layers) issued from retrogressive slumping occurring in the slump scars above their head area. The main body of each layer is then relatively undisturbed, showing the usual burial geotechnical gradients due to overburden pressure (i.e., decrease of water content and increase of unit weight and shear strength). At the toe of bottom current‐eroded slopes, a thick and homogeneous layer of Holocene muds overlies the Pleistocene muds; this Holocene layer has unappreciable burial depth gradient of its geotechnical parameters because of a high rate of modem and continuous deposition.  相似文献   
997.
The status of a fishery is often defined as the probability of fishing mortality rate exceeding a perilous level for long‐term sustainability. Lobster stock assessments are often subject to large uncertainty in input data and high levels of natural variability in lobster life history processes, which calls for incorporating uncertainty associated with both indicator and management reference points in an evaluation of biological risk of overfishing. Using a Monte Carlo simulation approach, we evaluated the impacts of uncertainty in modelling on the determination of the status of the Taitung spiny lobster (Panulirus penicillatus) fishery (Taiwan), which has not been quantitatively determined despite its commercial importance. The commonly used biological reference points derived from the per recruit model (F 0.1 the fishing mortality rate where the slope of the curve of yield‐per‐recruit model is 10% of the maximum slope and F 4Q%, the fishing mortality rate that reduces the expected egg production for a cohort of female lobsters to 40% of that produced in the absence of a fishery of the egg‐per‐recruit model) were influenced by uncertainties associated with lobster life history and fishery parameters. A large uncertainty in the current fishing mortality rate (F cnr) and estimates of biological reference points (F BRPs) increased the uncertainty in determining the risk of overexploitation throughout the confidence levels of the stochastic decision‐making framework. This simulation study suggests that the target reference point of F 40% is less sensitive to the input parameters’ uncertainty than F 0.1 We suggest a further evaluation of other F‐based references points and development of biomass‐based reference points before final selection and implementation for the management of the Taitung lobster fishery.  相似文献   
998.
Abstract

Concentrations of cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) were measured in adult barnacles (Elminius modestus Darwin) from Waitemata and Manukau Harbours in the Auckland area, New Zealand. As in studies on sediments reported in the literature, it was possible to identify areas of likely anthropogenic influence, e.g., around the Auckland Harbour Bridge for Pb, Cu, and Zn. Groups of individuals with highest concentrations for these metals showed 19.8–23.8 mg Pb kg?1, 198–266 mg Cu kg?1, and 4460–6530 mg Zn kg?1 (95% confidence limits, dry weight basis). Cd concentrations found for all barnacles from the Auckland area ranged from 0.8 to 3.1 mg kg?1. Two samples from Omaha Beach, 60 km north of Auckland, were used as a reference. Accordingly, groups of individuals with lowest concentrations for Pb, Cu, and Zn could be allocated to this site using the Student‐Newman‐Keuls Multiple Range Test (0.5–1.3 mg Pb kg?1, 8–10 mg Cu kg?1, and 144–214 mg Zn kg?1 ; 95% confidence limits). Only Cd concentrations were highest at Omaha Beach (8.6–12.1 mg Cd kg?1 ). This result may have arisen from “naturally” increased bio‐availabilities of certain metals in mangrove systems which are reported in the literature. Generally, metal concentrations in barnacles from the Auckland Harbour area and from Omaha Beach were within the wider range for E. modestus as well as other barnacle species reported in the international literature.  相似文献   
999.
Book reviews     

Climate change in contrasting river basins: adaptation strategies for water, food and environment. Edited by J Aerts and P Droogers. Published in 2004 by CABI Publishing, 288 p., hardcover. ISBN: 0–85199–835–6. Price: US$100 (orders: services@dadirect.com.au).

Australian water bugs. Their biology and identification (Hemiptera‐Heteroptera, Gerromorpha &; Nepomorpha). By Nils M Andersen? and Tom A Weir. Published in 2004 by CSIRO Publishing/Apollo Books, P.O. Box 1139, Collingwood, VIC 3066, Australia. 344 p., hardcover. ISBN: 0–643–090517. Price: AU$135.00 (orders: publishing.sales@csiro.au).

The Lakes Handbook. Volume I: Limnology and Limnetic Ecology. Volume II: Lake restoration and rehabilitation. Edited by Patrick O'Sullivan and Colin Reynolds. Published by Blackwell Publishing Ltd., 109 Cowley Road, Oxford OX4 1JF, United Kingdom (http//www.blackwellpublishing.com). Volume I (published in 2003) 712 p., hardcover. ISBN: 0632047976. Price: £125. Volume II (published in 2004) 568 p., hardcover. ISBN: 063204795X. Price: £125.  相似文献   
1000.
Abstract

Migrating and pre‐migrating western rock lobster Panulirus cygnus were tagged with datastorage tags that recorded temperature and pressure, which was converted to depth (Pressure (kPa) — surface pressure (kPa)/10)) at Dongara and Jurien Bay in Western Australia between December 2005 and December 2007. All lobsters were fitted with tag flotation devices, and returns were made by either commercial fishers or beachcombers who located detached tags. A total of 135 lobsters were released with “backpack” flotation tags, but only 84 (62.2%) of the backpacks carried data‐storage tags. Depths of release ranged from 5 to 113 m. Of the tagged lobsters released, commercial fishers recaptured 52 (38.5%), whereas 11 tags (8.1%) were found by beachcombers. At least 33%, and possibly up to 63%, of animals identified by their pale coloration as pre‐migrating individuals, failed to migrate. Those that did migrate (n = 11) were at liberty from 1 to 94 days and showed generally similar movement patterns in that they migrated only at night from darkness (after 2000 h) until after moonrise. However, their movement patterns were less constrained by the rising of the moon in deep water. Only 27% migrated nightly, compared with 73% that skipped migrating on one or more nights, to restart some days later. This latter proportion would likely have been considerably greater, but some migrating animals were only at large for short periods before recapture, and therefore had little time to show any variation to the nocturnal migration pattern. Individual speeds of migration during periods of activity were estimated for nine lobsters as 0.20 to 0.68 km h?1, with a mean speed of 0.44 km h?1, or 7.4 m min?1. Improved knowledge of daily movement patterns resulting from this study provides a potentially important input into technological improvements in bait and pot design.  相似文献   
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