The relationship between fish condition and the probability of being mature in American plaice (Hippoglossoides platessoides)     

Morgan  M. Joanne 《ICES Journal of Marine Science》2004,61(1):64-70

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Copper isotope fractionation by desert shrubs     

Jesica U. Navarrete  Marian Viveros  Joanne T. Ellzey  David M. Borrok 《Applied Geochemistry》2011

Copper has two naturally occurring stable isotopes of masses 63 and 65 which can undergo mass dependent fractionation during various biotic and abiotic chemical reactions. These interactions and their resulting Cu isotope fractionations can be used to determine the mechanisms involved in the cycling of Cu in natural systems. In this study, Cu isotope changes were investigated at the organismal level in the metal-accumulating desert plant, Prosopis pubescens. Initial results suggest that the lighter Cu isotope was preferentially incorporated into the leaves of the plant, which may suggest that Cu was actively transported via intracellular proteins. The roots and stems show a smaller degree of Cu isotope fractionation and the direction and magnitude of the fractionations was dependent upon the levels of Cu exposure. Based on this and previous work with bacteria and yeast, a trend is emerging that suggests the lighter Cu isotope is preferentially incorporated into biological components, while the heavier Cu isotope tends to become enriched in aqueous solutions. In bacteria, plants and animals, intracellular Cu concentrations are strictly regulated via dozens of enzymes that can bind, transport, and store Cu. Many of these enzymes reduce Cu(II) to Cu(I). These initial results seem to fit into a broader picture of Cu isotope cycling in natural systems where oxidation/reduction reactions are fundamental in controlling the distributions of Cu isotopes.  相似文献   

Early Holocene M~6 explosive eruption from Plosky volcanic massif (Kamchatka) and its tephra as a link between terrestrial and marine paleoenvironmental records     

Vera Ponomareva  Maxim Portnyagin  Alexander Derkachev  I. Florin Pendea  Joanne Bourgeois  Paula J. Reimer  Dieter Garbe-Schönberg  Stepan Krasheninnikov  Dirk Nürnberg 《International Journal of Earth Sciences》2013,102(6):1673-1699

We report tephrochronological and geochemical data on early Holocene activity from Plosky volcanic massif in the Kliuchevskoi volcanic group, Kamchatka Peninsula. Explosive activity of this volcano lasted for ~1.5 kyr, produced a series of widely dispersed tephra layers, and was followed by profuse low-viscosity lava flows. This eruptive episode started a major reorganization of the volcanic structures in the western part of the Kliuchevskoi volcanic group. An explosive eruption from Plosky (M~6), previously unstudied, produced tephra (coded PL2) of a volume of 10–12 km³ (11–13 Gt), being one of the largest Holocene explosive eruptions in Kamchatka. Characteristic diagnostic features of the PL2 tephra are predominantly vitric sponge-shaped fragments with rare phenocrysts and microlites of plagioclase, olivine and pyroxenes, medium- to high-K basaltic andesitic bulk composition, high-K, high-Al and high-P trachyandesitic glass composition with SiO₂ = 57.5–59.5 wt%, K₂O = 2.3–2.7 wt%, Al₂O₃ = 15.8–16.5 wt%, and P₂O₅ = 0.5–0.7 wt%. Other diagnostic features include a typical subduction-related pattern of incompatible elements, high concentrations of all REE (>10× mantle values), moderate enrichment in LREE (La/Yb ~ 5.3), and non-fractionated mantle-like pattern of LILE. Geochemical fingerprinting of the PL2 tephra with the help of EMP and LA-ICP-MS analyses allowed us to map its occurrence in terrestrial sections across Kamchatka and to identify this layer in Bering Sea sediment cores at a distance of >600 km from the source. New high-precision ¹⁴C dates suggest that the PL2 eruption occurred ~10,200 cal BP, which makes it a valuable isochrone for early Holocene climate fluctuations and permits direct links between terrestrial and marine paleoenvironmental records. The terrestrial and marine ¹⁴C dates related to the PL2 tephra have allowed us to estimate an early Holocene reservoir age for the western Bering Sea at 1,410 ± 64 ¹⁴C years. Another important tephra from the early Holocene eruptive episode of Plosky volcano, coded PL1, was dated at 11,650 cal BP. This marker is the oldest geochemically characterized and dated tephra marker layer in Kamchatka to date and is an important local marker for the Younger Dryas—early Holocene transition. One more tephra from Plosky, coded PL3, can be used as a marker northeast of the source at a distance of ~110 km.  相似文献   

Bronfenbrenner’s bioecological theory for modelling community resilience to natural disasters   总被引：1，自引：1，他引：0  

Helen J. Boon  Alison Cottrell  David King  Robert B. Stevenson  Joanne Millar 《Natural Hazards》2012,60(2):381-408

This paper advocates the use of Bronfenbrenner’s bioecological theory as a framework to analyse resilience at diverse scales. Bronfenbrenner’s bioecological theory can be employed to (a) benchmark social resilience, (b) target the priority interventions required and (c) measure progress arising from these interventions to enhance resilience to natural disasters. First, the paper explores resilience to natural disasters in the context of climatic change as building resilience is seen as a way to mitigate impacts of natural disasters. Second, concepts of resilience are systematically examined and documented, outlining resilience as a trait and resilience as a process. Third, issues arising in relation to the measurement of resilience are discussed. Fourth, Bronfenbrenner’s bioecological systems theory is described and proffered to model and assess resilience at different scales. Fifth, studies are described which have supported the use of the bioecological systems theory for the study of resilience. Sixth, an example of the use of Bronfenbrenner’s theory is offered and the paper concludes with suggestions for future research using Bronfenbrenner’s theory.  相似文献   

Deep optical imaging of the field of PC 1643+4631A&B – I. Spatial distributions and the counts of faint galaxies     

Toby Haynes  Garret Cotter †  Joanne C. Baker  Steve Eales  Michael E. Jones  Steve Rawlings  Richard Saunders 《Monthly notices of the Royal Astronomical Society》2002,334(2):262-282

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The long-singular ridges of the Halland Coastal Moraines,South-Western Sweden     

Joanne M. R. Fernlund 《第四纪科学杂志》1993,8(1):67-78

Radiocarbon dates of shells from the long singular ridges belonging to the Halland Coastal Moraines indicate that the ridges are younger than 12 400 yr BP, whereas according to the existing chronostratigraphy of western Sweden, the area was ice free before 12 700 yr BP. The ridges are interpreted as push moraines and not deposits of a stationary ice margin. The chronostratigraphy of western Sweden seems to need revision; however, further study is necessary before it is possible to present a new model.  相似文献   

Towards integrated disaster risk management: case studies and trends from Asia     

Aniello Amendola  Joanne Linnerooth-Bayer  Norio Okada  Peijun Shi 《Natural Hazards》2008,44(2):163-168

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Mass data processing of time series Landsat imagery: pixels to data products for forest monitoring     

Txomin Hermosilla  Michael A. Wulder  Joanne C. White  Nicholas C. Coops  Geordie W. Hobart  Lorraine B. Campbell 《International Journal of Digital Earth》2016,9(11):1035-1054

Free and open access to the Landsat archive has enabled the implementation of national and global terrestrial monitoring projects. Herein, we summarize a project characterizing the change history of Canada’s forested ecosystems with a time series of data representing 1984–2012. Using the Composite2Change approach, we applied spectral trend analysis to annual best-available-pixel (BAP) surface reflectance image composites produced from Landsat TM and ETM+ imagery. A total of 73,544 images were used to produce 29 annual image composites, generating ～400 TB of interim data products and resulting in ～25 TB of annual gap-free reflectance composites and change products. On average, 10% of pixels in the annual BAP composites were missing data, with 86% of pixels having data gaps in two consecutive years or fewer. Change detection overall accuracy was 89%. Change attribution overall accuracy was 92%, with higher accuracy for stand-replacing wildfire and harvest. Changes were assigned to the correct year with an accuracy of 89%. Outcomes of this project provide baseline information and nationally consistent data source to quantify and characterize changes in forested ecosystems. The methods applied and lessons learned build confidence in the products generated and empower others to develop or refine similar satellite-based monitoring projects.  相似文献   

Coastal curios? An analysis of ex situ beach finds for mapping new Palaeolithic sites at Happisburgh,UK     

Rachel Bynoe  Nick M. Ashton  Tim Grimmer  Peter Hoare  Joanne Leonard  Simon G. Lewis  Darren Nicholas  Simon Parfitt 《第四纪科学杂志》2021,36(2):191-210

Recent archaeological discoveries from exposures of the Cromer Forest-bed Formation at Happisburgh, UK, have radically changed interpretations of the nature and timing of early hominin occupation of northern latitudes, but this in situ archaeology is only one part of the picture. Surface finds of Pleistocene mammalian remains have been found along this coastline for centuries, with stone tools adding to this record over the past 7 years. The ex situ nature of these finds, however, means they are often seen as limited in the information they can provide. This work contributes to a growing body of research from a range of landscape and environmental contexts that seeks to demonstrate the value and importance of these ex situ assemblages. Here the focus is on Palaeolithic flint artefacts and Pleistocene mammalian remains recovered by a group of local collectors through systematic, GPS-recorded beach collection from 2013 to 2017, and their use in developing a methodology for working with ex situ Palaeolithic finds in coastal locations. The results demonstrate significant patterning that identifies unexplored exposures both onshore and offshore, considerably expanding the known extent of deposits and facilitating new insights into the wider archaeological landscape associated with the earliest occupation of northern Europe.  相似文献   

Influence of volume/mass on grain-size curves and conversion of image-analysis size to sieve size     

Joanne M.R. Fernlund  Robert W. Zimmerman  Danica Kragic 《Engineering Geology》2007,90(3-4):124-137

Image analysis of aggregates does not measure the same size as sieve analysis. The size of aggregates, determined by sieve analysis, is presented with respect to the percent cumulative mass, whereas image analysis does not measure mass. Results are often presented in percent particles or percent area. Several researchers have claimed that more accurate volume and mass determinations are necessary for accurate construction of grain-size curves. In the present work, several methods for reconstructing volume and thus mass of aggregates from image analysis (IA) have been tested to see how they influence the grain-size distribution curves. The actual mass of the individual particles was found to have little or no influence on the grain-size distribution curve, which is normalized and thus insensitive to mass. Accurate conversion of image-analysis size to sieve size is dependent upon how particles pass through sieves. Most existing methods base their conversion of image-analysis size to sieve size on the intermediate axis, multiplied by some factor. The present work shows that there is no direct correlation between the intermediate axes and sieve size. A universal conversion of image-analysis size to sieve size has been developed, using the minimum-bounding square around the minimum projected area. This measure yields very good correlation with sieve-analysis results.  相似文献