bluuebunny/crossref_metadata_2025 huggingface dataset:
A controlled longitudinal 5-year follow-up study of children at high and low risk for panic disorder and major depression
Authors: BIEDERMAN JOSEPH , PETTY CARTER , HIRSHFELD-BECKER DINA R. , HENIN AUDE , FARAONE STEPHEN V. , DANG DANIELLE , JAKUBOWSKI ALEKSANDRA , ROSENBAUM JERROLD F.
Published: May 2006

Background. To evaluate the longitudinal course of psychiatric disorders in children of parents with panic disorder (PD) and major depression (MD) as they transition through the period of risk from childhood into adolescence.

Method. Over a 5-year follow-up, we compared psychiatric disorders in four groups of children: (1) offspring of parents with PD plus MD (n=136); (2) offspring of parents with PD without MD (n=27); (3) offspring of parents with MD but without PD (n=53); and (4) offspring of non-PD non-MD parents (n=103).

Results. Parental PD was significantly associated with increased risk for anxiety disorders, irrespective of parental MD. Parental MD was associated with increased risk for MD, disruptive behavior disorders, and deficits in psychosocial functioning, irrespective of parental PD.

Conclusions. These longitudinal findings confirm and extend previous cross-sectional results documenting significant associations between PD and MD in parents and patterns of psychopathology and dysfunction in their offspring.
The social and linguistic conditioning of back vowel fronting across ethnic groups in Memphis, Tennessee
Authors: FRIDLAND VALERIE , BARTLETT KATHY
Published: May 2006

While a number of recent studies have documented the back vowel changes affecting White varieties nationally, few studies have examined back vowel fronting in non-Anglo dialects or compared the social and linguistic commonalties and contrasts in the progress of the shift and the vowel classes affected. The present study explores how ethnic and regional alignment affects the dispersion of fronting in three key back vowel classes, the BOOT, BOOK, and BOAT classes. Using instrumental acoustic measurement of relevant vowel classes, this article will examine both the social and linguistic conditioning governing the fronting of these classes in White and Black speakers in Memphis, TN, looking at these results in light of those found by Anderson, Milroy & Nguyen (2002), Ash (1996), and Labov (1994) elsewhere in the US.
Stour and Blyth as English river-names
Authors: COATES RICHARD
Published: May 2006

The disputed etymology of the river-name Stour is revisited. It is suggested that an ‘Old European’ river-name was taken for an OE adjective, and that this adjective with its antonym represented in the river-name Blyth expressed the principal opposition in the classificatory system imposed on rivers in the Anglo-Saxon period.
Watching English grammar change: a case study on complement selection in British and American English
Authors: RUDANKO JUHANI
Published: May 2006

This article traces the complement selection properties of the adjective accustomed from the eighteenth century to the present. The adjective has frequently selected sentential complements, but the study illustrates a major change affecting the form of such complements. In the eighteenth century they were regularly of the to infinitive type, but today they are almost as regularly of the to -ing type. Both syntactic and semantic factors are identified in the article as having an impact on the change. The study also compares the pace of the change in British and American English, arguing that incipient change was discernible in both varieties as early as the nineteenth century. It is argued further that, at the present time, the change has been completed more fully in American English than in British English. This conclusion is reached by considering sentences with extraction or filler–gap dependencies. The data in the article come from large electronic corpora.
The history of the genitive case from the Old English period onwards
Authors: KOIKE TAKESHI
Published: May 2006

The history of the genitive case from Old English onwards, specifically the diversity of genitival functions in Old English, and the subsequent development of the case as determiner marker as claimed in Rosenbach (2002), can be explained coherently by assuming NP status for genitive nominals and nondistinct categorial status of the determiner class in OE. This article argues that OE, as an inflected language, encodes events in terms of roles carried by participants, and that the genitive case signalled partial or nonparticipation of a designated thing. This enabled a genitive nominal to be subordinated to another NP, which gives a coherent gestalt of the two things, and also to function as a full NP elsewhere. At the same time, the loose categorial status of determiners made it possible for a genitive nominal in prenominal position to function as a determiner. After the OE period, the determiner category became more distinct from others, and a genitive nominal, being a member of this category, ceased to be able to function as NP.
The segmental phonology of nineteenth-century Tristan da Cunha English: convergence and local innovation
Authors: SCHREIER DANIEL , TRUDGILL PETER
Published: May 2006

This article looks into convergence processes that involve distinct phonological systems in dialect contact situations, exemplified by the variety of English that developed on Tristan da Cunha, an island in the South Atlantic Ocean. Based on a discussion of the community's social history and an auditory analysis of the segmental phonology of late nineteenth-century Tristan da Cunha English, this article reconstructs the early contact scenario and looks into both phonological convergence and independent innovative mechanisms that accompany new-dialect formation. The data presented here show that dialect contact gives rise to mixing of several inputs (so that ‘new’ dialects draw features from several ancestral varieties), that the interaction of transplanted dialects may also trigger independent, variety-specific mechanisms, and that the interplay of feature retention, input mixing, and local innovation lead to distinctive and (on occasion) endemic varieties of English.
The variability of compound stress in English: structural, semantic, and analogical factors
Authors: PLAG INGO
Published: May 2006

It is generally assumed that noun–noun (NN) compounds in English are stressed on the left-hand member (e.g. cóurtroom, wátchmaker). However, there is a considerable amount of variation in stress assignment (e.g. silk tíe, Madison Ávenue, singer-sóngwriter), whose significance and sources are largely unaccounted for in the literature. This article presents an experimental study in which three competing hypotheses concerning NN stress assignment are tested. The stress patterns of novel and existing compounds, as obtained in a reading experiment with native speakers of American English, were acoustically measured and analyzed. The results show that there is indeed a considerable amount of variation in stress assignment, and that all three hypothesized factors, i.e. structure, semantics, and analogy, are relevant, though to different degrees. On a theoretical level, the findings strongly suggest that a categorical approach cannot be upheld and that probability and analogy need to be incorporated into an adequate account of stress assignment in noun–noun constructions. The article also makes a methodological contribution to the debate in showing that experimental studies using pitch measurements can shed new light on the issue of variable compound stress.
Linguistic change, sociohistorical context, and theory-building in variationist linguistics: new-dialect formation in New Zealand
Authors: MEYERHOFF MIRIAM
Published: May 2006

Elizabeth Gordon, Lyle Campbell, Jennifer Hay, Margaret Maclagan, Andrea Sudbury, and Peter Trudgill, 2004. New Zealand English: its origins and evolution. Cambridge: Cambridge University Press. ISBN 0 521 64292 2. Hb £55.00, US$85.00.

Peter Trudgill, 2004. New-dialect formation: the inevitability of colonial Englishes. Edinburgh: Edinburgh University Press/Georgetown: Georgetown University Press. ISBN 0 7486 1876 7. Hb £45.00.
Descriptive genitives in English: a case study on constructional gradience
Authors: ROSENBACH ANETTE
Published: May 2006

This article offers an in-depth treatment of a ‘nonprototypical’ s-genitive, i.e. the descriptive genitive (e.g. women's magazine), which has so far received little attention in the grammars of English. Various types of descriptive genitives are distinguished, i.e. classifying, metaphorical, and generic genitives. In addition, the article raises a number of theoretical issues of a more general nature, such as the delimitation of syntactic phrases from compounds. Most importantly, it is argued that descriptive genitives provide evidence for constructional gradience in the English noun phrase in two ways: (1) gradience between determiner genitives and descriptive genitives, and (2) gradience between s-genitives and noun + noun sequences. A central claim is made that semantic overlaps may give rise to constructional gradience. In this respect the present article complements earlier accounts of gradience that have emphasized the importance of structural criteria only. The article concludes with a brief consideration of measure genitives, which are in many ways similar to descriptive genitives.
Colonizing currencies. Beasts, banknotes and the colour of money in South Africa Taking stock. A response to Turgeon and Creighton
Authors: Comaroff Jean , Comaroff John L.
Published: May 2006

In Archaeological dialogues 12.2 Jean and John Comaroff explored the role of commensuration – the mechanisms that render equitable and negotiable different orders of value – in the production of society and history. While equilibration, standardization and conversion are implicated in most theories of money and commodification, their nature as social processes has not been adequately specified, above all in the construction of universalizing ideologies and modernist political and economic regimes. They pursue these processes in relation to one African theatre, examining the ways in which different regimes of value, brought up against one another in the encounter between the southern Tswana peoples and European colonizers, became the subject of both conflict and complex mediation. Cows, coin and contracts – which had the capacity to construct and negate difference – soon were invested here with magical qualities. But colonized peoples were also sensitive to the capacity of such currencies to enable or impede convertibility, and to the forms of abstraction and incorporation they permit. Which is why, in South Africa and elsewhere, those currencies often became metonymic of the contestations of value on which colonial struggles, tout court, were played out.

In this short essay they respond to the comments on their article by John Creighton and Laurier Turgeon.
Archaeology at the edge. An archaeological dialogue with Martin Hall
Authors: Lucas Gavin
Published: May 2006

Archaeology in South Africa has always been political and no one has articulated this relationship better than Martin Hall in a career that has spanned both the political upheavals in South Africa and the theoretical transformations in archaeology over the past four decades. In research that has traversed the Iron Age to the Internet, he has explored the multifarious ways in which material culture operates in everyday life and how power is mobilized through materiality. He is also an example of a scholar who thoroughly embodies the very modern duality of the local and the global through his work, which is both highly engaged within the context of South Africa (and Africa in general), while also clearly international in its scope and relevance.
Archaeology without -isms
Authors: Baines Andrew , Brophy Kenneth
Published: May 2006

This paper examines the division that has grown up in contemporary archaeology between practical and theoretical branches of the discipline. It argues that the two sides of this schism are archaeological versions of objectivism and subjectivism, and that they really represent a single dualism. To break out of this, what is needed is an approach to thinking and doing archaeology that recognizes the embodied nature of archaeological engagements with material culture, together with an understanding of the emergent, relational character of archaeological data. In the light of this discussion, we attempt to redefine the building blocks of archaeology (material culture and the past), and to show with a case study how such an archaeology might generate new insights in practice.
The trouble with paradigms. A historiographical study on the development of ideas in the discipline of castle studies
Authors: Mercer David
Published: May 2006

In the years leading up to the First World War the academic understanding of the earthen mounds we know as mottes underwent a series of dramatic changes. Exploration of the paradigms behind these viewpoints tells us much about the way in which knowledge comes into being and is used. In particular, archaeologists have created their own foundation myths, complete with hero and demon figures, which serve to emphasize a progressive account of research. The reality is often somewhat more reactionary. In this paper I argue that archaeological histories have impeded understanding of the discipline as the complexities of research remain hidden. As viewpoints become entrenched, creative thought is stifled because the subject is believed to be understood. In castle studies, one a-priori paradigm is that the English motte-and-bailey castle was introduced by the Normans, an idea commonly attributed to Ella Armitage. This paper explores the context behind the adoption of this idea through a case study focusing on changes in understanding. Acrimonious dismissal of alternative points of view has maintained the dominance of this paradigm. I conclude that critical historiographies such as this best serve the development of future understanding of the discipline.
Mapping for gender. Interpreting artefact distribution inside 1st- and 2nd-century A.D. forts in Roman Germany
Authors: Allison Penelope M.
Published: May 2006

Artefacts from military bases of the early Roman Empire potentially indicate not only the presence of women and children inside the walls, but also their movements, activities and impact on fort life. This paper explores dynamic approaches to categorizing and gendering artefacts for more holistic investigations of artefact assemblages. It uses GIS mapping techniques to analyse the distribution patterns of ‘gendered’ artefacts within three forts on the German frontier – Vetera I, Ellingen and Oberstimm. It investigates the social significance of these patterns within and between the forts to better understand women's place in this sphere.
Next stop: Gender. Women at Roman military forts in Germany
Authors: Tomášková Silvia
Published: May 2006

As a Palaeolithic archaeologist I am often surprised by the paucity of research on issues of social relations in more recent time periods. The wealth of archaeological evidence and written texts seems so plentiful from where I stand. Thus when I look into Greek and Roman archaeology for examples of research on gendered being and for a discussion of difference in the past I am reminded that archaeological evidence is the consequence of research questions as much as their starting point. We only see that which we are able to comprehend, and archaeological finds and their interpretations become visible through the questions we ask. Issues of gender in the archaeological record are a very useful reminder of the firm grip that disciplinary traditions have on our imagination. In archaeology material determinism and scientific positivism, coupled with the straw man of subjective distortion of objective reality, continue to drive our imagination at a comfortable speed that does not threaten to overturn the theoretical cart. Furthermore, firmly held disciplinary boundaries, such as those that separate history and the study of texts and representations from the practice of archaeological fieldwork, can result in a limited conversation between the social and material traces of the past. In this sense classical archaeology can appear suddenly familiar to a prehistoric archaeologist, if the refusal of history in one context effectively parallels its absence in another. As someone both used to prehistoric contexts featuring minimal physical evidence, and interested in issues of gender as understood by contemporary feminist scholars, I wonder why this should be so.
‘Safe’ genders?
Authors: Casella Eleanor Conlin
Published: May 2006

As historical archaeology has expanded from its origins in the ‘settler nations’ of the post-colonial world, an increasing number of European scholars have argued for a radical reorientation of the subfield. But if historical archaeology is to be accepted as the ‘archaeology of literate societies’, the profound interdisciplinarity of the subject must be embraced. While the presence of written documents can indeed be a luxury, providing for richer or more personalized interpretations of the past, it can also be a curse, demanding careful attention to the interplay between material and textual sources of evidence. Allison's example of ‘gendering’ the Roman military landscape provides a crucial first step towards a more socially oriented archaeology of the classical world. It also demonstrates both the opportunities and limitations faced by scholars of the literate past.
The ‘romanization’ of gender archaeology
Authors: Sørensen Marie Louise Stig
Published: May 2006

Allison's paper shows how the complex world of real-life social relations, dependencies and needs may be extracted from the small finds and the mundane domestic aspects of life associated with a site – even when that site is a Roman fort. In her approach Allison does not presume that society in its totality is mirrored in these finds; rather her apparently modest, but in fact potentially significant, point is that concrete aspects of how people organised their relationships, and especially the spatial aspects of these relationships, are revealed by such finds. In this emphasis Allison makes important contributions to two core areas of concern: one is the character of domestic life within Roman forts during the 1st and 2nd centuries A.D., and the other, more theoretical concern, is how we make interpretative links between objects and social roles and identities. These two areas of concern are not, however, given equal standing in her arguments. The reflection upon the interpretative project of engendering is largely nested within the discussion of how one may find evidence of women and children within the Roman fort. There appears to be little acknowledgement of how some aspects of this concern need to be discussed at a general level separate from the specific questions about gender as part of social relations within this particular type of settlement. This omission is probably due to the limited space, but it brings up important points about how we reach interpretation.
Engendering change in our understanding of the structure of Roman military communities
Authors: James Simon
Published: May 2006

One of the most important developments in the study of the northern frontier provinces in recent years has been growing realization of the complexity of the populations living within, as well as around, imperial Roman military bases. It is clear that, even within the walls, such bases were not the exclusive preserve of soldiers, or even males. (It has been especially delicious to see the outraged reaction of some conservative practitioners of Limesforschung to the idea that there could possibly have been women living inside Roman forts.)
Women in Roman forts – lack of knowledge or a social claim?
Authors: Becker Thomas
Published: May 2006

The classic idea of the Roman army, especially of the legions, is that of a man's world, where discipline and military drill dominate, and where there is no room for women, whatever their social status or function. This idea has been fostered by the picture painted by the antique authors, in which fighting by women is reserved to goddesses (Athena/Minerva) and exceptional personages. The normal female is described as a mother or wife, whose chief occupations were confined to the organization of the household, the up-bringing of the children, spinning and weaving (Marquardt 1975, 58). This role model fits in excellently with the social structure of 19th-century Europe, where women were also absent from military camps. This, in turn, can be traced back to the to the Prussian view of military virtues, which would be diminished by the presence of women. Many concepts of Roman military archaeology have their origin in this period. In many ways these traditions still influence our views on Roman life, as analyses of the roles of women and children in archaeological illustrations have shown (Röder 2002; Becker and Hölschen in press). German archaeological research, especially, concentrates on questions of building-structures, military units or dating, whilst social aspects of life in the camps or on the frontier are normally neglected.
Response. Historical complexity
Authors: Allison Penelope M.
Published: May 2006

The concerns of these five commentators are too diverse to be dealt with comprehensively in this short response, but I emphasize that this paper introduces a project which aims to ‘redress the balance’ with regard to Roman military bases as domestic spaces and whose theoretical and methodological underpinnings are wide-ranging and complex. I will briefly address a few basic points.
Reinterpreting the Burton‐McPherron‐Russell equation for predicting Dst
Authors: Vasyliunas Vytenis M.
Published: May 2006

The simple equation proposed by Burton et al. (1975) and extensively applied with considerable success for predicting the time series of the geomagnetic storm index Dst is generally derived solely from conservation of energy, without describing the specific energization processes. More recently, numerical simulation models of ring current evolution have relied on the opposite approximation: they describe the energization and loss processes, without imposing conservation of energy. The fact that predictions of Dst by both methods agree reasonably well with each other and with observations suggests that some of the assumptions need to be reexamined. The Dessler‐Parker‐Sckopke theorem, in its generalized form, contains a magnetotail surface term proportional to the open magnetic flux, the time derivative of which equals the difference between the electric field integrals along the dayside and along the nightside reconnection lines. The dayside integral contributes a term to the equation for (d/dt)Dst that is identical in form and (within the uncertainties) consistent in magnitude with the empirically determined source term of the Burton‐McPherron‐Russell equation. The success of the empirical equation in predicting Dst then implies that the remaining terms in the equation, the contribution of the nightside integral of the magnetotail term and the rate of increase of plasma energy content, sum to zero. The simplest interpretation is that the energy of ring current plasma is indeed being supplied primarily from the magnetotail by processes that involve nightside reconnection in an essential way.
Basement structures from satellite‐derived gravity field: South China Sea ridge
Authors: Braitenberg Carla , Wienecke Susann , Wang Yong
Published: May 2006

The satellite‐derived gravity over the South China Sea reveals high spatial frequency signals not present in the bathymetric models. The most evident is a linear feature of near 1000 km length, which parallels the South China Sea extinct spreading center. We formulate a crustal model of the South China Sea by constrained forward and inverse gravity modeling. The effect of the sediment layer is evaluated using the global sediment thickness model of NOAA and fitting the sediment compaction model to observed density values. The General Bathymetric Chart of the Oceans (GEBCO) and constraining data from seismology on crustal thickness are integrated in the inversion process, which includes the flexural isostasy model. The model crustal thickness values vary between 8 and 12 km and between 10 and 20 km over the oceanic and continental crustal part of the South China Sea, respectively. The elastic thickness is below 6 km over most of the sea, with lowest values in the margin (between 2 and 4 km). Finally, we invert the gravity data for the gravity‐equivalent basement topography, which in sediment‐covered areas corresponds to the basement and in sediment‐free areas coincides with the bathymetry. We find a continuous ridge structure along the entire midbasin: It changes from a steep valley in the younger SW basin to a less pronounced valley in the NE basin, lined with seamounts. Our model shows the spreading center to be continuous and to bend from the older EW orientation to the younger SW‐NE orientation rather than being made up of two separate axis segments.
Three‐dimensional joint inversion for magnetotelluric resistivity and static shift distributions in complex media
Authors: Sasaki Yutaka , Meju Max A.
Published: May 2006

Accurate interpretation of magnetotelluric (MT) data in the presence of static shift arising from near‐surface inhomogeneities is an unresolved problem in three‐dimensional (3‐D) inversion. While it is well known in 1‐D and 2‐D studies that static shift can lead to erroneous interpretation, how static shift can influence the result of 3‐D inversion is not fully understood and is relevant to improved subsurface analysis. Using the synthetic data generated from 3‐D models with randomly distributed heterogeneous overburden and elongate homogeneous overburden that are consistent with geological observations, this paper examines the effects of near‐surface inhomogeneity on the accuracy of 3‐D inversion models. It is found that small‐scale and shallow depth structures are severely distorted while the large‐scale structure is marginally distorted in 3‐D inversion not accounting for static shift; thus the erroneous near‐surface structure does degrade the reconstruction of smaller‐scale structure at any depth. However, 3‐D joint inversion for resistivity and static shift significantly reduces the artifacts caused by static shifts and improves the overall resolution, irrespective of whether a zero‐sum or Gaussian distribution of static shifts is assumed. The 3‐D joint inversion approach works equally well for situations where the shallow bodies are of small size or long enough to allow some induction such that the effects of near‐surface inhomogeneity are manifested as a frequency‐dependent shift rather than a constant shift.
Heterogeneous fault stresses from previous earthquakes and the effect on dynamics of parallel strike‐slip faults
Authors: Duan Benchun , Oglesby David D.
Published: May 2006

We combine a viscoelastic model for the interseismic process and an elastodynamic model for the coseismic process to explore the dynamics (over multiple earthquake cycles) of two parallel strike‐slip faults embedded in a two‐dimensional full space. The step over fault geometry results in a buildup of heterogeneous fault stress near the step over. This heterogeneous stress accumulates at the early stage of the evolution of the fault system, and finally stabilizes after a number of earthquake cycles. The heterogeneity in fault stress varies with the geometrical parameters (e.g., width and along‐strike overlap/gap) of the step over, as well as the rupture history of the fault system. This heterogeneous fault stress from previous earthquakes has significant effects on earthquake rupture initiation, propagation, and termination. The locations with a low normal stress level near a step over are favorable points for earthquake initiation. Rupture can jump a 4 km wide compressional step over and a 8 km or wider dilational step over if the fault system has historically experienced many earthquakes. A young step over with less induced heterogeneity allows rupture to jump only smaller step over widths. These results may have important implications for seismic hazard analysis in areas where segmented strike‐slip faults predominate, particularly for estimating maximum earthquake potential.
Low‐frequency variability in the Southern Ocean region in a simplified coupled model
Authors: Maze Guillaume , D'Andrea Fabio , Colin de Verdière Alain
Published: May 2006

Patterns of interannual variability of the ocean‐atmosphere coupled system in the Southern Hemisphere extratropics are studied with a simple dynamical model in order to determine the basic physical processes of interaction independently of tropical forcing. The model used is an atmospheric quasi‐geostrophic model coupled to a “slab” oceanic mixed layer, which includes mean geostrophic advection by the Antarctic Circumpolar Current (ACC). The ocean‐atmosphere coupling occurs through surface heat fluxes and Ekman current heat advection. In a fully coupled simulation, the atmospheric part of the model, which includes high‐frequency transient eddies at midlatitudes, exhibits a strong Southern Annular Mode (SAM) as the first mode of variability at interannual timescales. The SAM‐related wind anomalies induce Ekman currents in the mixed layer which produce sea surface temperature anomalies. These are then advected along by the ACC. A forced mechanism where the ocean role is reduced to advect the sea surface temperature (SST) appears sufficient to reproduce the main features of the variability. Nevertheless, a positive feedback of the ocean was also found. It operates through anomalous Ekman currents heat advection and contributes to the maintenance of the SST anomaly.
Relations between postglacial fluvial incision rates and uplift rates in the North Island, New Zealand
Authors: Litchfield Nicola , Berryman Kelvin
Published: May 2006

Fluvial incision rates are increasingly being used as a proxy for rock uplift rates for inland settings. We test the validity of this approach by comparing incision rates and rock uplift rates along the Hikurangi Margin, New Zealand. Postglacial fluvial incision rates were calculated by measuring the difference in altitude between the Last Glacial Maximum (LGM) terrace tread (18 ± 2 calendar ka) and the present river bed for 10 major rivers (catchment areas ∼1400–5900 km2). Incision rates have thus been measured over a half glacial cycle. They also represent average rates over the last 18 kyr, during which time variations are likely due to processes such as knickpoint retreat. Rock uplift rates have been estimated from (1) altitude differences between the treads of pairs of fluvial fill terraces (∼55 and ∼18 calendar ka) assumed to have formed at the same altitude (i.e., rock uplift relative to the geoid), (2) present‐day altitudes of Late Neogene paleoshoreline marker horizons (1.6–5.7 Ma) (i.e., rock uplift relative to sea level), and (3) present‐day altitudes of Neogene mudstones for which maximum depth of burial has been calculated from porosity (i.e., rock uplift relative to sea level). These rock uplift rates overestimate tectonic uplift rates because they do not take into account isostatic compensation due to erosion. Mean incision rates range up to 11.7 mm yr−1, and mean rock uplift rates range up to 4, 1, and 0.9 mm yr−1 for the three methods, respectively. We have made some qualitative and semiquantitative observations about nontectonic controls on postglacial incision rates and find that localized influence only is exerted by rainfall, base level, and bedrock lithology, while negative or no correlations are shown with LGM fluvial fill thickness and stream power. Incision rates and uplift rates display a rough correlation, with incision rates typically 1.5–5 times uplift rates. This relation suggests that tectonic uplift is likely to exert an important control on fluvial incision in the Hikurangi Margin.
Modeling physical and biogeochemical controls over carbon accumulation in a boreal forest soil
Authors: Carrasco Jonathan J. , Neff Jason C. , Harden Jennifer W.
Published: May 2006

Boreal soils are important to the global C cycle owing to large C stocks, repeated disturbance from fire, and the potential for permafrost thaw to expose previously stable, buried C. To evaluate the primary mechanisms responsible for both short‐ and long‐term C accumulation in boreal soils, we developed a multi‐isotope (12, 14C) soil C model with dynamic soil layers that develop through time as soil organic matter burns and reaccumulates. We then evaluated the mechanisms that control organic matter turnover in boreal regions including carbon input rates, substrate recalcitrance, soil moisture and temperature, and the presence of historical permafrost to assess the importance of these factors in boreal C accumulation. Results indicate that total C accumulation is controlled by the rate of carbon input, decomposition rates, and the presence of historical permafrost. However, unlike more temperate ecosystems, one of the key mechanisms involved in C preservation in boreal soils examined here is the cooling of subsurface soil layers as soil depth increases rather than increasing recalcitrance in subsurface soils. The propagation of the 14C bomb spike into soils also illustrates the importance of historical permafrost and twentieth century warming in contemporary boreal soil respiration fluxes. Both 14C and total C simulation data also strongly suggest that boreal SOM need not be recalcitrant to accumulate; the strong role of soil temperature controls on boreal C accumulation at our modeling test site in Manitoba, Canada, indicates that carbon in the deep organic soil horizons is probably relatively labile and thus subject to perturbations that result from changing climatic conditions in the future.
A resolution for the coiling direction paradox in Neogloboquadrina pachyderma
Authors: Darling Kate F. , Kucera Michal , Kroon Dick , Wade Christopher M.
Published: May 2006

We present new data on genotypic differences and biogeographic distribution of coiling types in the living planktonic foraminiferal morphospecies Neogloboquadrina pachyderma. The genetic evidence demonstrates that coiling direction in N. pachyderma is a genetic trait, heritable through time, and is not a morphological feature reflecting ecophenotypic variation. The two opposite coiling morphotypes appear to have diverged during the late Miocene, and they have distinctly different ecologies. In combination with fossil evidence, biogeography, and ecology the degree of genetic distinction between the two coiling types of N. pachyderma strongly implies that they should be considered different species. We propose the adoption of the widely recognized name N. incompta for the right coiling morphospecies. The genetic evidence also demonstrates a low level (<3%) of aberrant coiling associated with both morphotypes. The abundance of these aberrant specimens has no relationship with the environment. These findings have important consequences for the use of N. pachyderma and N. incompta as paleoceanographic signal carriers in polar and subpolar waters.
Observations of gas flow in porous media using a light transmission technique
Authors: Parker Laila , Yarwood Rockie , Selker John
Published: May 2006

A novel technique for quantitative nondestructive study of two‐dimensional disposition of gas phase in unsaturated porous media is presented. Carbon dioxide was pumped through a backlit 1 cm thick chamber packed with translucent sand, which was variably saturated with water containing the pH indicator dye methyl red. As the carbon dioxide dissolved in the pore water, lowering the pH and changing the dye color, a CCD camera captured images of the resultant changes in transmitted light. These digital image files were then processed using a series of calibrated steps to relate light intensity to dye attenuation, dye attenuation to solution pH, and solution pH to aqueous and gaseous carbon dioxide concentration. The final product was a series of false‐color images showing the development of the gaseous carbon dioxide plume. Limitations were found that will require further development, including more attention to calibration of dye concentration versus observed transmission and investigation of dye solubility across the range of pH values employed. With refinement, this technique may prove to be a useful tool in studying the complexities of gas phase transport in variably saturated porous media.
Terrestrial water mass load changes from Gravity Recovery and Climate Experiment (GRACE)
Authors: Seo K.‐W. , Wilson C. R. , Famiglietti J. S. , Chen J. L. , Rodell M.
Published: May 2006

Recent studies show that data from the Gravity Recovery and Climate Experiment (GRACE) is promising for basin‐ to global‐scale water cycle research. This study provides varied assessments of errors associated with GRACE water storage estimates. Thirteen monthly GRACE gravity solutions from August 2002 to December 2004 are examined, along with synthesized GRACE gravity fields for the same period that incorporate simulated errors. The synthetic GRACE fields are calculated using numerical climate models and GRACE internal error estimates. We consider the influence of measurement noise, spatial leakage error, and atmospheric and ocean dealiasing (AOD) model error as the major contributors to the error budget. Leakage error arises from the limited range of GRACE spherical harmonics not corrupted by noise. AOD model error is due to imperfect correction for atmosphere and ocean mass redistribution applied during GRACE processing. Four methods of forming water storage estimates from GRACE spherical harmonics (four different basin filters) are applied to both GRACE and synthetic data. Two basin filters use Gaussian smoothing, and the other two are dynamic basin filters which use knowledge of geographical locations where water storage variations are expected. Global maps of measurement noise, leakage error, and AOD model errors are estimated for each basin filter. Dynamic basin filters yield the smallest errors and highest signal‐to‐noise ratio. Within 12 selected basins, GRACE and synthetic data show similar amplitudes of water storage change. Using 53 river basins, covering most of Earth's land surface excluding Antarctica and Greenland, we document how error changes with basin size, latitude, and shape. Leakage error is most affected by basin size and latitude, and AOD model error is most dependent on basin latitude.
Genetic algorithms for the design of looped irrigation water distribution networks
Authors: Reca Juan , Martínez Juan
Published: May 2006

A new computer model called Genetic Algorithm Pipe Network Optimization Model (GENOME) has been developed with the aim of optimizing the design of new looped irrigation water distribution networks. The model is based on a genetic algorithm method, although relevant modifications and improvements have been implemented to adapt the model to this specific problem. It makes use of the robust network solver EPANET. The model has been tested and validated by applying it to the least cost optimization of several benchmark networks reported in the literature. The results obtained with GENOME have been compared with those found in previous works, obtaining the same results as the best published in the literature to date. Once the model was validated, the optimization of a real complex irrigation network has been carried out to evaluate the potential of the genetic algorithm for the optimal design of large‐scale networks. Although satisfactory results have been obtained, some adjustments would be desirable to improve the performance of genetic algorithms when the complexity of the network requires it.
Ignorance is bliss: Or seven reasons not to use uncertainty analysis
Authors: Pappenberger F. , Beven K. J.
Published: May 2006

Uncertainty analysis of models has received increasing attention over the last two decades in water resources research. However, a significant part of the community is still reluctant to embrace the estimation of uncertainty in hydrological and hydraulic modeling. In this paper, we summarize and explore seven common arguments: uncertainty analysis is not necessary given physically realistic models; uncertainty analysis cannot be used in hydrological and hydraulic hypothesis testing; uncertainty (probability) distributions cannot be understood by policy makers and the public; uncertainty analysis cannot be incorporated into the decision‐making process; uncertainty analysis is too subjective; uncertainty analysis is too difficult to perform; uncertainty does not really matter in making the final decision. We will argue that none of the arguments against uncertainty analysis rehearsed are, in the end, tenable. Moreover, we suggest that one reason why the application of uncertainty analysis is not normal and expected part of modeling practice is that mature guidance on methods and applications does not exist. The paper concludes with suggesting that a Code of Practice is needed as a way of formalizing such guidance.
Snowmelt dominance of dissolved organic carbon in high‐latitude watersheds: Implications for characterization and flux of river DOC
Authors: Finlay Jacques , Neff Jason , Zimov Sergei , Davydova Anna , Davydov Sergei
Published: May 2006

Transport of dissolved organic carbon (DOC) from land to water is an important but poorly known component of northern carbon cycles. We examined seasonal patterns of arctic river DOC flux, focusing on the largely uncharacterized snowmelt period. High‐intensity sampling of the Kolyma River showed rapid increases in DOC concentration during peak discharge, yielding unique DOC‐water flux relationships compared to summer, fall and winter. Our annual DOC flux estimates were 31% higher than previous estimates for the basin based on few or no snowmelt samples. Synthesis of the sparse literature show that 55% of arctic river DOC flux occurs during snowmelt. Biogeochemical characterizations of DOC in large rivers are usually done after snowmelt runoff, and are thus unrepresentative of most DOC transported to the Arctic Ocean. Finally, the proportion of annual DOC flux at snowmelt is considerably higher than for water, suggesting that cold season production is an important but little known process regulating arctic DOC transport.
A long‐range forecast of Arctic summer sea‐ice minimum extent
Authors: Drobot Sheldon D. , Maslanik James A. , Fowler Charles
Published: May 2006

This paper discusses the development of simple multiple linear regression (MLR) models for predicting the annual pan‐Arctic minimum sea‐ice extent at monthly intervals from February through August. The predictor data is based on mean monthly weighted indices of sea‐ice concentration (WIC), surface skin temperature (WST), surface albedo (WAL), and downwelling longwave flux at the surface (WDL). The final regression equations retain either one or two sea ice and surface energy and radiation balance predictors, and each of the MLR models is superior to climatology, persistence, or random chance models. The mean absolute error (MAE) for the MLR models decreases from 0.36 × 106 km2 in February to 0.15 × 106 km2 in August; the corresponding r2 increases from 0.46 in February to 0.90 in August. In addition to improving long‐range predictions, the models provide insight into the physical mechanisms affecting recent large reductions in sea‐ice extent.
Radial transport of fluctuation energy in a two-field model of drift-wave turbulence
Authors: Gürcan Ö. D. , Diamond P. H. , Hahm T. S.
Published: May 2006

A theory of spatial propagation of turbulence, referred to as turbulence spreading, is developed for the two-field model of drift wave turbulence. Markovian closure expressions for the flux of kinetic and internal fluctuation energies are systematically derived. Simplified closure expressions are used to obtain two coupled reaction-diffusion equations for kinetic and internal energy. The efficacy of various nonlinear interaction mechanisms for spreading is analyzed systematically. Spreading of internal energy is predicted to “lead” that of kinetic energy. The important role of zonal flow damping in spreading is identified, but zonal flows are shown not to be the dominant agents of turbulence spreading.
In situ observation of DNA hybridization and denaturation by surface infrared spectroscopy
Authors: Miyamoto Ko-Ichiro , Ishibashi Ken-Ichi , Yamaguchi Ryo-Taro , Kimura Yasuo , Ishii Hisao , Niwano Michio
Published: May 2006

We have investigated in situ the hybridization and denaturation of DNA in aqueous solution using infrared absorption spectroscopy (IRAS) in the multiple internal reflection (MIR) geometry. We demonstrate that conformational changes of DNA strands due to hybridization (binding of two complementary single-stranded DNAs) and denaturation (separation of double helix at elevated temperatures) are reflected in the infrared absorption spectra in the frequency region where vibrational modes of the bases of DNA appear. Comparison with results of ab initio cluster calculation shows that hybridization produces the specific CO carbonyl stretching vibration modes in the hydrogen-bonded base pairs. The ratio of absorbance of the CO stretching peak at 1690cm−1 to the absorbance at 1660cm−1 provides a definitive metric for determining DNA hybridization. We also reveal that the CO stretching vibration modes of the bases of a single strand is strongly influenced by the surrounding water molecules that may interact with the CO groups of the bases. The present results suggest that MIR-IRAS is applicable to label-free, high-sensitive biosensors that provide insight about the gene expression and a variety of biological interactions such as DNA-protein interactions.
Theoretical analysis of strain and strain decay in InAs∕GaAs(001) multilayer quantum dot growth
Authors: Tomić S. , Howe P. , Harrison N. M. , Jones T. S.
Published: May 2006

The results of analytically based calculations of the various strain components within and outside InAs quantum dots (QDs) in a GaAs matrix are presented. The calculations performed here take into account cubic crystal strain anisotropy and spatial grading of the indium composition. The assumptions regarding the shape and compositional profile of the QDs have been refined and reflect experimental findings from previous morphological studies. Generally, cone-shaped QDs are modeled with and without truncation, and the composition is either pure InAs or is assumed to change linearly from 50% at the bottom to 100% at the top. The exact QD dimensions—height and base diameter—have been obtained from scanning tunneling microscopy and atomic force microscopy. The first part of the calculation addresses structures containing a single QD layer. Particular emphasis is placed on evaluating the decay of strain in the growth direction, as this is known to affect QD nucleation and growth in subsequent layers. In the second part the calculations are expanded to structures containing two layers of QDs with separations of 10, 20, and 30nm. It is shown that the biaxial strain component decays more rapidly in the case of an isolated QD compared with a QD in the second layer of a structure with 10nm spacing. In this bilayer structure, the hydrostatic strain within the first layer QDs is significantly smaller compared with that in the upper QDs and the implications for the electronic band structure are discussed. Our calculations provide insight into trends in (multilayer) QD structures that are not easily observed experimentally.
Temperature-dependent photoluminescence from type-II InSb∕InAs quantum dots
Authors: Lyublinskaya O. G. , Solov’ev V. A. , Semenov A. N. , Meltser B. Ya. , Terent’ev Ya. V. , Prokopova L. A. , Toropov A. A. , Sitnikova A. A. , Rykhova O. V. , Ivanov S. V. , Thonke K. , Sauer R.
Published: May 2006

We report on the photoluminescence (PL) studies of InSb-enriched quantum dots (QDs) which are grown by molecular beam epitaxy in an InAs matrix. InSb∕InAs heterostructures have a nominal thickness of InSb insertions in the range of 0.6–2 monolayers and exhibit bright PL up to room temperature in the mid-infrared spectral range. The PL temperature dependence gives evidence that each InSb insertion can be regarded as an ensemble of QDs subject to carrier transfer even at low temperatures. Both QD PL energy and line-shape variations with temperature can be described employing Fermi-Dirac carrier statistics.