bluuebunny/crossref_metadata_2025 huggingface dataset:
Marine parasites as pollution indicators: an update
Authors: WILLIAMS H. H. , MACKENZIE K.
Published: November 2003

Eight major reviews are cited to indicate a recent knowledge explosion on the use of marine parasites as potential indicators of pollution. A literature update is given for the period 1995–2001. An analysis of the publications cited is used to provide 10 refined criteria for selecting parasites as indicator/monitor species. Previously unpublished data on Diclidophora merlangi and Dictyocotyle coeliaca confirm their value as potential indicators of hydrocarbon pollution in the North Sea. An extensive knowledge of D. merlangi is summarised to emphasize its potential value as an indicator species and also to encourage studies on the health status and immune responses of its host when subjected to pollutant stressors and infection with this monogenean. A discussion focuses on publications which have reported significant recent advances in this area of research and also on accompanying issues, problems and controversies. These selected publications are used to suggest species, stages in the development of species and assemblages of species worthy of further more detailed investigations into their value as indicators/monitors of pollution. It is predicted that further good progress will be made when contaminants can be accurately identified, their precise effects on both host and parasite can be measured by histochemical and biological methods and the roles of contaminants and parasites in causing disease can be assessed separately. About 100 references are cited.
Endocrine disruption, parasites and pollutants in wild freshwater fish
Authors: JOBLING S. , TYLER C. R.
Published: November 2003

Disruption of the endocrine system has been shown to occur in wild freshwater fish populations across the globe. Effects range from subtle changes in the physiology and sexual behaviour of fish to permanently altered sexual differentiation, impairment of gonad development and/or altered fertility. A wide variety of adverse environmental conditions may induce endocrine disruption, including sub-optimal temperatures, restricted food supply, low pH, environmental pollutants, and/or parasites. Furthermore, it is conceivable that any/all of these factors could act simultaneously to cause a range of disparate or inter-related effects. Some of the strongest evidence for a link between an adverse health effect, as a consequence of endocrine disruption, and a causative agent(s) is between the condition of intersex in wild roach (Rutlius rutilus) in UK rivers and exposure to effluents from sewage treatment works. The evidence to indicate that intersex in roach (and other cyprinid fish living in these rivers) is caused by chemicals that mimic and/or disrupt hormone function/balance in treated sewage effluent is substantial. There are a few parasites that affect the endocrine system directly in fish, including the tape worm Ligula intestinalis and a few parasites from the micropsora phylum. L. intestinalis acts at the level of the hypothalamus restricting GnRH secretion (resulting in poorly developed gonads) and is one of the very few examples where an endocrine disrupting event has been shown to result in a population-level effect (reducing it). It is well established that many parasites affect the immune system and thus the most common effect of parasites on the endocrine system in fish is likely to be an indirect one.
Cadmium effects onIchthyophthirius: evidence for metal-sequestration in fish tissues following administration of recombinant vaccines
Authors: BISHARYAN Y. , CHEN Q. , HOSSAIN M. M. , PAPOYAN A. , CLARK T. G.
Published: November 2003

We are developingTetrahymena thermophilaas a delivery system for recombinant vaccines against parasitic protozoa, including the common fish parasite,Ichthyophthirius multifiliis. T. thermophilacell lines expressingI. multifiliisgenes under the control of a cadmium-inducible metallothionein gene promoter conferred strong protection against a lethal parasite challenge when administered parenterally to naïve fish. Nevertheless, given that heavy metals can be toxic to parasites, a question arose as to whether protection resulted from Cd residues carried over with the vaccine, rather than acquired immunityper se. To address this issue, we examined the sensitivity ofI. multifiliisto Cdin vitroand determined Cd concentrations in different host tissues following i.p. injection of juvenile channel catfish with the recombinant vaccine. We found that CdCl2at concentrations [ges ]50 ppb were lethal toI. multifiliistherontsin vitro. Furthermore, Cd concentrations were clearly elevated in fish tissues and reached levels equivalent to 74 ng/g wet weight (74 ppb) in the skin within 14 days of injection with recombinantT. thermophila. Nevertheless, fish injected with non-transformedTetrahymenagrown in the presence or absence of CdCl2showed no significant difference in either relative survival or parasite load following direct challenge withI. multifiliis.
Fish macroparasites as indicators of heavy metal pollution in river sites in Austria
Authors: SCHLUDERMANN C. , KONECNY R. , LAIMGRUBER S. , LEWIS J. W. , SCHIEMER F. , CHOVANEC A. , SURES B.
Published: November 2003

This paper describes two approaches to evaluate the use of fish macroparasites as bioindicators of heavy metal pollution at selected river stretches in Austria. Firstly changes in the diversity and richness of endoparasites of the cyprinid barbel, Barbus barbus (L.), were tested in relation to heavy metal contents in the aquatic system. Secondly, the bioaccumulation potential of cadmium, lead and zinc was assessed in the acanthocephalan, Pomphorhynchus laevis (Müller, 1776), and compared with that in the muscle, liver and intestine of its barbel host. The present results indicated that in order to validate the role of parasite community patterns related to heavy metal pollution, more investigations on food web dynamics, interelationships between parasites and the presence/absence of intermediate hosts will be essential. Heavy metal concentrations differed significantly between the organs of barbel and P. laevis (P=0·001) with levels up to 2860 fold in the parasite. The high level of heavy metal accumulation in P. laevis compared with that in its barbel host, suggests that despite variability in the parasite infrapopulation, host mobility and feeding behaviour, P. laevis is a most sensitive indicator of heavy metals in aquatic ecosystems.
Pollution toxicity to the transmission of larval digeneans through their molluscan hosts
Authors: MORLEY N. J. , IRWIN S. W. B. , LEWIS J. W.
Published: November 2003

The increased occurrence of pollutants in ecosystems is a continuing area of concern. It is known that numerous diseases of wild aquatic animals can occur with decreased or increased prevalences in areas associated with high or chronic levels of pollution. This may have serious implications for environmental health. There has consequently been an increasing number of laboratory and field studies on disease transmission under polluted conditions, especially focusing on digeneans of medical or economic importance. The effect of pollutants to the transmission of larval digeneans (miracidia, cercariae, metacercariae) and snail-digenean interactions is therefore considered. An overview and interpretation of the published literature on laboratory and field studies is provided. It is apparent from these studies that the influence of pollutants on digenean transmission is highly complex with much of the observed effects in the laboratory often masked by a complexity of other factors in the field. Future studies would benefit from a standardisation of experimental procedures, increasing the number of combined laboratory and field studies, and increasing the complexity of the experiments undertaken.
The expression of immune-regulatory genes in rainbow trout,Oncorhynchus mykiss, during a natural outbreak of proliferative kidney disease (PKD)
Authors: HOLLAND J. W. , GOULD C. R. W. , JONES C. S. , NOBLE L. R. , SECOMBES C. J.
Published: November 2003

Proliferative kidney disease (PKD) is a parasitic infection of salmonid fish characterized by an apparently abnormal immune response to the presence of the myxozoan parasite,Tetracapsuloides bryosalmonae. In order to examine the nature of the immune response at the molecular level, the expression of a range of immune regulatory genes, including cytokines and cyclooxygenase (COX)-2 was examined in naive unexposed fish and in naive fish exposed to parasite-infected water at three points during the course of a natural outbreak of PKD. Since fish with advanced PKD pathology generally exhibit increased susceptibility to secondary infections which is typical of stress/cortisol-mediated immune suppression, a further aim of this work was to examinein vitrothe influence of the glucocorticoid cortisol on the bacterial lipopolysaccharide (LPS)-induced expression of the trout cytokine genes studied. Two weeks after the initial sampling, naive exposed fish showed a specific profile of up-regulated tumor necrosis factor (TNF)-α2, COX-2 and, to a lesser extent, transforming growth factor (TGF)-β1 expression. As the disease pathology increased, TNF-α2 and COX-2 expression returned to normal levels. Stress levels of cortisol suppressed the LPS inducibility of pro-inflammatory cytokine genes, although TGF-β1 and TNF-α2 appeared to be refractory. These data demonstrate that specific immune responses at the molecular level are affected during PKD infection, with the cortisol suppression of cytokine expressionin vitroproviding a possible link to PKD-mediated cytokine down-regulation and immune suppression.
Inflammatory interactions in fish exposed to pollutants and parasites: a role for apoptosis and C reactive protein
Authors: HOOLE D. , LEWIS J. W. , SCHUWERACK P. M. M. , CHAKRAVARTHY C. , SHRIVE A. K. , GREENHOUGH T. J. , CARTWRIGHT J. R.
Published: November 2003

Although previous studies have highlighted the inflammatory responses of fish infected with parasites and exposed to pollutants, very little is known about how these two stressors interact within the fish. In this review, which also contains original data, the effect of these two parameters on the fish inflammatory response is assessed and, in particular, the role of apoptosis and the acute phase protein, C reactive protein, is evaluated. InCyprinus carpioexposed to 0·5 mg NH4+l−1or 0·1 mg Cd2+l−1and experimentally infected with the blood fluke,Sanguinicola inermis, the pollutant type and the order in which the fish experiences the parasite and toxicant, significantly affects the ultrastructural appearance and cellular content of the pronephros and thymus. This is reflected in the intensity of infection where the pollutant appears to have less effect on an established infection. Both stressors, pollutant and infection, may mediate their effects via the endocrine system. Studies have revealed that cortisol at 100 ng ml−1is able to induce apoptosis in pronephric cells of carp and that an increase in apoptosis is associated with an increase in phagocytosis in this immune organ. In addition, C reactive protein, which is used as a biomarker of the inflammatory response in humans and other mammals, is evaluated as a possible indicator of physiological states in fish exposed to pathogens and pollutants.
Norwegian witchcraft trials: a reassessment
Authors: KNUTSEN GUNNAR W.
Published: November 2003

Twenty years have passed since Hans Eyvind Næss published what remains the only complete study of Norwegian witchcraft trials. This article considers the work done since that time, and surveys the state of research on witchcraft trials in Norway. Drawing on a recent registration of all known extant witchcraft trial records in Norway as well as recent research, I show how there was a much higher degree of regional differences within Norway than Næss allowed for, as well as a much greater degree of diabolism (the charge that witches took Satan as their lord) in Norwegian trials.
The origins of the children of the London Foundling Hospital, 1741–1760: a reconsideration
Authors: LEVENE ALYSA
Published: November 2003

The infants left at the London Foundling Hospital in the first twenty years of its operation have generally been classed as illegitimate. This study examines some of the characteristics of the children who entered the hospital between 1741 and 1760, and points to a far larger component of legitimate infants than has previously been suspected, up to a third being born in wedlock. The backgrounds of the children varied considerably, as did the reasons for their abandonment, with a stress on personal and economic misfortune for both married and single parents. The higher level of legitimacy among the foundlings than has been thought has implications for the illegitimacy ratio of London, pointing to relatively low levels, in common with those found for the seventeenth and nineteenth centuries.
Mistress or wife? Fukui Sakuzaemon vs. Iwa, 1819–1833
Authors: NAGATA MARY LOUISE
Published: November 2003

This article is a case study addressing the issues of concubines, legitimacy and inheritance in early modern Japan. Although there was some discussion about the legal status of concubines/mistresses in the late nineteenth century in Meiji Japan, the topic has attracted surprisingly little recent research. The Meiji debate was concerned with how to treat concubines under a system that both outlawed bigamy and recognized common law marriages. The later academic debate refers back to the earlier interpretations of the legal and social status of concubines, with one side claiming they were nearly equal to wives and the other claiming they were little more than servants. In this study I review the above debates and then address the issue with a study of an inheritance case that began in 1819 when Fukui Sakuzaemon adopted an heir from outside the family. Sakuzaemon's concubine Iwa played an important role in the inheritance agreement and in further developments in the suit, including later efforts to disinherit the new head and gain support for her daughters by Sakuzaemon. I use the documents from this complicated case to analyse the social and legal statuses of Iwa and the relationship of her daughters to the Fukui family and its assets.
Up close and personal: a case study of the development of three English fillers
Authors: FELDMAN ANDREA , MENN LISE
Published: November 2003

As Peters (2001) has suggested, the young child's use of fillers seems to indicate awareness of distributionally-defined slots in which some as yet unidentified material belongs. One may view a filler as an emergent transitional form; as a slot that serves as an underspecified lexical entry for the accumulation of phonological and functional information; or as prosodic ‘sentence padding’. We trace the development of three fillers in one English-acquiring child through seven months, from their first appearance about 1;9 through their re-analysis as English functors about age 2;4. We show how the description of these fillers requires an elaboration of the current framework for describing the emergence of morphology, from a one-dimensional to a multi-dimensional model. Finally, we argue that the neglect of such transitional and under-defined elements gives a false picture of development, making it appear as if language development takes place in discontinuous steps.
Rules and construction effects in learning the argument structure of verbs
Authors: DEMUTH KATHERINE , MACHOBANE 'MALILLO , MOLOI FRANCINA
Published: November 2003

Theorists of language acquisition have long debated the means by which children learn the argument structure of verbs (e.g. Bowerman, 1974, 1990; Pinker, 1984, 1989; Tomasello, 1992). Central to this controversy has been the possible role of verb semantics, especially in learning which verbs undergo dative-shift alternation in languages like English. The learning problem is somewhat simplified in Bantu double object constructions, where all applicative verbs show the same order of postverbal objects. However, Bantu languages differ as to what that order is, some placing the benefactive argument first, and others placing the animate argument first. Learning the language-specific word-order restrictions on Bantu double object applicative constructions is therefore more akin to setting a parameter (cf. Hyams, 1986). This study examined 100 three- to eight-year-old children's knowledge of word order restrictions in Sesotho double object applicatives. Performance on forced choice elicited production tasks found that four-year-olds showed evidence of rule learning, although eight-year-olds had not yet attained adult levels of performance. Further investigation found lexical construction effects for three-year-olds. These findings suggest that learning the argument structure of verbs, even when lexical semantics is not involved, may be more sensitive to lexical construction effects than previously thought.
The use of grammatical morphemes reflecting aspect and modality by children with specific language impairment
Authors: LEONARD LAURENCE B. , DEEVY PATRICIA , MILLER CAROL A. , CHAREST MONIQUE , KURTZ ROBERT , RAUF LEILA
Published: November 2003

Children with specific language impairment (SLI) have well-documented problems in the use of tense-related grammatical morphemes. However, in English, tense often overlaps with aspect and modality. In this study, 15 children with SLI (mean age 5;2) and two groups of 15 typically developing children (mean ages 3;6 and 5;3) were compared in terms of their use of previously studied morphemes in contexts that more clearly assessed the role of aspect. The children's use of less frequently studied morphemes tied to modality or tense was also examined. The children with SLI were found to use -ing to mark progressive aspect in past as well as present contexts, even though they were relatively poor in using the tense morphemes (auxiliary was, were) that should accompany the progressive inflection. These children were inconsistent in their use of third person singular -s to describe habitual actions that were not occurring during the time of their utterance. However, the pattern of the children's use suggested that the source of the problem was the formal tense feature of the inflection, not the habitual action context. The children's use of modal can was comparable to that of the typically developing children, raising the possibility that the modality function of possibility had been learned without necessarily acquiring the tense feature of this morpheme. These children's proficiency with can suggests that their bare verb stem productions should probably not be re-interpreted as cases of missing modals. Together these findings suggest that the more serious tense-related problems seen in English-speaking children with SLI co-occur with a less impaired ability to express temporal relations through aspect and modality.
Potential mechanisms of avian sex manipulation
Authors: PIKE THOMAS W. , PETRIE MARION
Published: November 2003

The aim of this review is to consider the potential mechanisms birds may use to manipulate the sex of their progeny, and the possible role played by maternal hormones. Over the past few years there has been a surge of reports documenting the ability of birds to overcome the rigid process of chromosomal sex determination. However, while many of these studies leave us in little doubt that mechanisms allowing birds to achieve this feat do exist, we are only left with tantalizing suggestions as to what the precise mechanism or mechanisms may be. The quest to elucidate them is made no easier by the fact that a variety of environmental conditions have been invoked in relation to sex manipulation, and there is no reason to assume that any particular mechanism is conserved among the vast diversity of species that can achieve it. In fact, a number of intriguing proposals have been put forward. We begin by briefly reviewing some of the most recent examples of this phenomenon before highlighting some of the more plausible mechanisms, drawing on recent work from a variety of taxa. In birds, females are the heterogametic sex and so non‐Mendelian segregation of the sex chromosomes could conceivably be under maternal control. Another suggestion is that follicles that ultimately give rise to males and females grow at different rates. Alternatively, the female might selectively abort embryos or‘dump lay’eggs of a particular sex, deny certain ova a chance of ovulation, fertilization or zygote formation, or selectively provision eggs so that there is sex‐specific embryonic mortality. The ideas outlined in this review provide good starting points for testing the hypotheses both experimentally (behaviourally and physiologically) and theoretically.
The use of multiple cues in mate choice
Authors: CANDOLIN ULRIKA
Published: November 2003

An increasing number of studies find females to base their mate choice on several cues. Why this occurs is debated and many different hypotheses have been proposed. Here I review the hypotheses and the evidence in favour of them. At the same time I provide a new categorisation based on the adaptiveness of the preferences and the information content of the cues. A few comparative and empirical studies suggest that most multiple cues are Fisherian attractiveness cues or uninformative cues that occur alongside a viability indicator and facilitate detection, improve signal reception, or are remnants from past selection pressures. However, much evidence exists for multiple cues providing additional information and serving as multiple messages that either indicate general mate quality or enable females that differ in mate preferences to choose the most suitable male. Less evidence exists for multiple cues serving as back‐up signals. The importance of receiver psychology, multiple sensory environments and signal interaction in the evolution of multiple cues and preferences has received surprisingly little attention but may be of crucial importance. Similarly, sexual conflict has been proposed to result in maladaptive preferences for manipulative cues, and in neutral preferences for threshold cues, but no reliable evidence exists so far. An important factor in the evolution of multiple preferences is the cost of using additional cues. Most theoretical work assumes that the cost of choice increases with the number of cues used, which restricts the conditions under which preferences for multiple cues are expected to evolve. I suggest that in contrast to this expectation, the use of multiple cues can reduce mate choice costs by decreasing the number of mates inspected more closely or the time and energy spent inspecting a set of mates. This may be one explanation for why multiple cues are more common than usually expected. Finally I discuss the consequences that the use of multiple cues may have for the process of sexual selection, the maintenance of genetic variation, and speciation.
Fine-tuning in living systems: early evolution and the unity of biochemistry
Authors: Cairns-Smith Graham
Published: November 2003

There is a set of molecules common to all forms of life on Earth that are often described as ‘the molecules of life’. This should not be taken to imply that life can only be made from just these components, or that life on Earth always was. These molecules are parts of a machine, the essential design of which is also common to all life on Earth, but which is so complex and well organized that it looks like a product of evolution through natural selection, an evolution that was effectively frozen at some stage before a ‘last common ancestor’. There are hints in the structure of our biochemical pathways as to which of the present components of this machine came first, and intimations of an earlier altogether different genetic system in our ancestry.
The navigation of biological hyperspace
Authors: Morris Simon Conway
Published: November 2003

A recurrent argument against the reality of biological evolution is the claim that there is insufficient time for the emergence of biological complexity. Such a view is a staple of creation ‘scientists’, but even cosmologists and biochemists have been overheard murmuring similar sentiments. Certainly the stock response, that the scientific evidence for evolution is overwhelming, must be made. However, it is also the case that whilst the efficacity of natural selection is not in dispute, it is context-free and fails to explain the specificities of life. This observation is usually greeted with a Gallic shrug: ‘Yes, the biosphere is very rich, but so what?’ Indeed, the standard scientific response is that evolution is dogged by contingent happenstance, with the implication that a given complexity, say intelligence, is an evolutionary fluke. This, however, is inconsistent with the ubiquity of evolutionary convergence. Here I outline the argument for such convergence providing a ‘road-map’ of possibilities that arguably has universal applications and as importantly points to a much deeper structure to life.
Searching for sentience: SETI today
Authors: Shostak G. Seth
Published: November 2003

For more than four decades, a small group of researchers has sought to find evidence of extraterrestrial intelligence in situ, by detecting microwave signals that would betray its existence. Despite the failure to find these signals so far, there is continued and even accelerated effort to press the search. Recent advances include greater emphasis on experiments at optical wavelengths, and the construction of a new radio telescope that is deliberately designed for such reconnaissance. In addition to these instrumental improvements, several strategies have been proposed that might better the chances of ‘looking in the right place, at the right time’. This review of the current state of SETI research concludes with a speculative look at the nature of the sought-for extraterrestrials, and when it is likely we might find them.
Intelligent life in cosmology
Authors: Tipler Frank J.
Published: November 2003

I shall present three arguments for the proposition that intelligent life is very rare in the universe. First, I shall summarize the consensus opinion of the founders of the modern synthesis (Simpson, Dobzhanski and Mayr) that the evolution of intelligent life is exceedingly improbable. Secondly, I shall develop the Fermi paradox: if they existed, they would be here. Thirdly, I shall show that if intelligent life were too common, it would use up all available resources and die out. But I shall show that the quantum mechanical principle of unitarity (actually a form of teleology!) requires intelligent life to survive to the end of time. Finally, I shall argue that, if the universe is indeed accelerating, then survival to the end of time requires that intelligent life, though rare, to have evolved several times in the visible universe. I shall argue that the acceleration is a consequence of the excess of matter over antimatter in the universe. I shall suggest experiments to test these claims.
Online auctions as a research tool: A field experiment on ethnic discrimination
Authors: Shohat Michael , Musch Jochen
Published: November 2003

It is argued that online auctions offer a promising new platform for conducting field experiments in various areas of psychology. Both advantages and problems associated with the new method are discussed. To demonstrate its feasibility, a field experiment on ethnic discrimination was conducted. In an online auction, user names identified two sellers as being either of German or Turkish origin. Parallel sets of DVD movie discs were offered by both sellers. Contrary to previous research showing considerable discrimination against members of the Turkish minority in everyday situations, seller ethnicity had no effect on sale prices and number of bidders. However, auctions conducted under the German user name received their winning bids earlier than those run under the Turkish user name.
Legasthenie und Rechenstörung - Einführung in den Themenschwerpunkt
Authors: Petermann Franz
Published: November 2003

Zusammenfassung. Es werden Befunde und neue Ansätze zu folgenden Bereichen ausgeführt: Prävalenz, Ursachen, Diagnostik, Förderung und Therapie bei Legasthenie und Dyskalkulie. Auf die ungünstige Entwicklungsprognose beim Vorliegen solcher Störungen wird eingegangen. Neue Ansätze im Rahmen der Prävention und Förderung werden skizziert.
Dyskalkulie - Forschungsstand und Perspektiven
Authors: Jacobs Claus , Petermann Franz
Published: November 2003

Zusammenfassung. Es wird ein Überblick über die Entwicklung der Rechenfunktionen gegeben. Im Detail geht der Beitrag auf die Epidemiologie, Erklärungskonzepte zur Zahlenverarbeitung und zur Dyskalkulie ein. Des Weiteren werden verschiedene Modelle zur Zahlenverarbeitung und Rechenfunktion dargestellt; zudem werden Rechentests bewertet. Auf einen integrativen Therapieansatz wird eingegangen.
Einflussfaktoren für den Zusammenhang von Rechen- und Schriftsprachleistungen im frühen Grundschulalter
Authors: Schwenck Christina , Schneider Wolfgang
Published: November 2003

Zusammenfassung. Mit der vorliegenden Studie sollte ein statistischer Nachweis für die Existenz einer Gruppe von Kindern im frühen Grundschulalter mit kombinierten Defiziten im rechnerischen und schriftsprachlichen Bereich neben solchen mit isolierten Lernschwächen erbracht und die Struktur kognitiver Basisfertigkeiten für diese Gruppen ermittelt werden. Eine Stichprobe mit 115 Erstklässlern wurde hinsichtlich ihrer Rechen- und Schriftsprachleistungen sowie ihrer Aufmerksamkeit, Zählfertigkeit, Gedächtnisleistung und phonologischen Bewusstheit untersucht. Mittels einer Clusteranalyse wurden vier Gruppen ermittelt: Während sich eine Gruppe durch gute Rechen- und Schriftsprachleistungen auszeichnete, wies eine zweite Gruppe unterdurchschnittliche Leistungen in beiden Bereichen bei gleichzeitigem Underachievement in den kognitiven Basisfertigkeiten auf. Bei einer dritten Gruppe, die eine isolierte Schwäche im rechnerischen Bereich zeigte, konnte eine besondere Schwäche im Bereich der Aufmerksamkeit festgestellt werden, während die vierte Gruppe mit isolierten Defiziten im Schriftsprachbereich Schwächen im Bereich der phonologischen Bewusstheit und dem Gedächtnis zeigte.
Das Kindergartenalter: Sensitive Periode für die Entwicklung numerischer Fertigkeiten
Authors: Weinhold Zulauf Monika , Schweiter Martin , von Aster Michael
Published: November 2003

Zusammenfassung. Im Rahmen einer Längsschnittstudie wurden die numerischen Fertigkeiten von 334 Vorschulkindern einer repräsentativen Stichprobe aus dem Kanton Zürich (Schweiz) untersucht. Auf der Grundlage neurowissenschaftlicher Theoriebildung wurde hierzu eine Kindergartenversion der Neuropsychologischen Testbatterie für Zahlenverarbeitung und Rechnen (ZAREKI-K) erstellt. Die Ergebnisse zeigen, dass Kinder vor Schuleintritt bereits über ein beträchtliches zahlenbezogenes Wissen verfügen, wobei allerdings erhebliche interindividuelle Unterschiede bestehen. Der Vergleich des Wissensniveaus im 1. und im 2. Halbjahr lässt zudem auf einen rapiden Wissenszuwachs während des Kindergartenjahres vor Einschulung schließen, wovon allerdings Mädchen und Knaben nicht gleichermaßen profitieren. Während im 1. Halbjahr die Mädchen noch leicht bessere Werte erzielen, schneiden die Knaben im 2. Halbjahr signifikant besser ab. Mögliche Ursachen und Konsequenzen für eine Vorschuldidaktik werden diskutiert.
Langzeitverlauf und Behandlungsansätze bei einer Fütter- und Essstörung im frühen Kindesalter
Authors: Klemm Silke , Blanz Bernhard
Published: November 2003

Zusammenfassung. Für den steigenden Anteil früh beginnender Essstörungen sind Einflüsse auf das Krankheitsgeschehen noch unzureichend bekannt und kasuistische Studien zur Analyse dieser Phänomene kaum vorhanden. Hier wird daher über eine Fütterstörung und eine sich daraus entwickelnde frühe atypische Anorexia nervosa eines neunjährigen Mädchens berichtet. Dazu werden die Funktion des Essverhaltens als ein Ausdruck von Entwicklungskonflikten und gestörten Lernprozessen sowie multimodale Behandlungsstrategien dargestellt und dahinter die interaktive Bedeutung der Symptomatik hervorgehoben.
Feeding and metabolism of mesozooplankton in the equatorial Pacific high‐nutrient, low‐chlorophyll zone along 180°
Authors: Gaudy Raymond , Champalbert Gisèle , Le Borgne Robert
Published: November 2003

Feeding, respiration, and excretion rates (ammonium and phosphate) of mesozooplankton from the equatorial Pacific upper water column (0–100 m) were measured along the 180th meridian at different stations between 8°S and 8°N, and more repeatedly, at two time series stations, located at 3°S (TSS1) and the equator (TSS2). Only particles of size >8 μm were grazed by the organisms used for the experiments. Grazing rates were higher at TSS1. Ammonium excretion was also maximum at TSS2, resulting in lower O/N values. This suggests that food particles were richer in terms of protein content at the equator, as is also indicated by the lower C/N ratio of particles and the higher proportion of heterotrophic protozoans. Some variations in mesozooplankton specific composition (more carnivorous copepods being present in the equatorial samples) could also explain these O/N differences. Diel variations were observed. Significantly higher grazing, respiration (only at TSS1), and excretion rates were recorded during the day, suggesting that feeding activity was related to the daytime increase of primary production. Using the grazing rates determined under experimental conditions, the grazing pressure on the stock of food particles >8 μm was very low (<1%) and the daily food intake (2.7–3.1% of the zooplankton body carbon), was far from compensating for respiration losses (22% of the body carbon). We conclude that the experimentally measured feeding activity was underestimated because of methodological problems. More realistic values were obtained from energy balance considerations, using measured respiration rates as an indication of minimal carbon requirement and extrapolating to ingestion using literature coefficients for assimilation efficiency (0.7) and net growth efficiency (0.4). According to these calculations the daily food carbon intake necessary to sustain both secondary production and respiration needs would be equivalent to 63% of the mesozooplankton body carbon, and the grazing pressure on >8‐μm food particles would reach 14% of the standing stock d−1.
Statistical study of short‐period gravity waves in OH and OI nightglow images at two separated sites
Authors: Ejiri M. K. , Shiokawa K. , Ogawa T. , Igarashi K. , Nakamura T. , Tsuda T.
Published: November 2003

Using airglow images of the near‐infrared OH band (720–910 nm) and OI (557.7 nm) line, we investigated seasonal, latitudinal, and local time variations of short‐period gravity waves. The images were obtained at two locations in Japan that are ∼1200 km apart, Rikubetsu (43.5°N, 143.8°E) and Shigaraki (34.9°N, 136.1°E), between October 1998 and October 1999. Our analysis has focused on small‐scale gravity waves with wavelengths less than 40 km and dominant phase speeds of ∼20–50 m/s. Wave occurrences for both OH and OI at Rikubetsu and Shigaraki are significantly higher than 60%, with a slightly larger value in summer. The occurrences increase from evening to midnight. There are no obvious local time dependencies in horizontal wavelength, propagation direction, and phase speed. The propagation directions in summer are either northward or northeastward at both locations. However, in winter the propagation directions at Rikubetsu are generally westward (NW, W, and SW), whereas those at Shigaraki are only southwestward. From simultaneous wind observation by the MF radars at Wakkanai (45.4°N, 141.7°E) and Yamagawa (31.2°N, 130.6°E), we discuss possible influences of Doppler and thermal ducting, wind filtering, and source distribution of gravity waves propagating from the lower atmosphere to the airglow heights in the mesopause region.
A preferred scale for landscape forced mesoscale circulations?
Authors: Baidya Roy Somnath , Weaver Christopher P. , Nolan David S. , Avissar Roni
Published: November 2003

The Regional Atmospheric Modeling System was used in two previous studies to simulate mesoscale circulations forced by surface heterogeneity in the Central U. S. and Amazonia. In this work, spectral analysis is used to compare the horizontal length scales of these simulated circulations with the scale of the surface heterogeneity. For both cases, the organized mesoscale circulations are confined within a preferred length scale range (10–20 km) that is significantly different from the dominant length scale of the surface heterogeneity. Multiscale landscape patchiness in these two regions tend to produce eddies at a wide range of scales, but the land‐atmosphere interaction processes act as a medium‐pass filter to select intermediate‐scale circulations. This scale of response remains relatively unchanged despite significant day‐to‐day variations in the synoptic situation and the mean surface heat flux.
Sensitivity of model‐simulated summertime precipitation over the Mississippi River Basin to the spatial distribution of initial soil moisture
Authors: Georgescu Matei , Weaver Christopher P. , Avissar Roni , Walko Robert L. , Miguez‐Macho Gonzalo
Published: November 2003

Using a numerical model, the Regional Atmospheric Modeling System (RAMS), we simulate July precipitation over parts of the Mississippi River Basin and surroundings for each of three years, 1995–1997, with six different initial soil moisture patterns: three (control, dry, and wet) with a realistic (observationally based) spatial distribution, and three (control, dry, and wet) with a horizontally homogeneous distribution. Our goal is to determine the impact on future simulated precipitation of changing the initial soil moisture spatial distribution. The spatially homogeneous initial soil moisture pattern represents, in effect, a “wet west/dry east” anomaly imposed on the realistic soil moisture pattern (that reflects the west‐to‐east climatological gradient). The impact of this anomaly, i.e., increasing soil moisture in the western half and decreasing it in the eastern half of the simulation domain, is most pronounced for the dry experiments and weakens nonlinearly with increasing domain‐average initial soil moisture. In the dry regime, the impact is to enhance the total monthly precipitation in both the west and east. We examine the various terms in the atmospheric moisture budget to interpret these results. The changes in precipitation in the runs with a homogeneous compared to realistic initial soil moisture spatial pattern are consistent with enhanced evaporation in the western half of the model domain accompanied by enhanced west‐to‐east horizontal moisture transport that helps restore the initially depleted soil moisture in the east. In this manner, the zonal moisture flux acts toward re‐establishing the initial climatological soil moisture pattern of the region, thus acting as a negative feedback mechanism. In addition, the soil moisture anomaly generally produces diminished meridional moisture transport into the simulation domain from the south through a decrease in the low‐level meridional wind speed. This decrease in meridional flux acts in the same direction as the zonal flux change in the west, and in the opposite direction to the zonal flux change in the east. Since this change is most pronounced in the west, it therefore also contributes to the overall negative feedback of the atmospheric dynamics on the initial soil moisture. The persistence timescale of the impact of this particular soil moisture anomaly pattern on precipitation is on the order of 3 months in the dry regime. Sensitivity of the results to a change in convection scheme is also explored.
Total water storage in the Arkansas‐Red River basin
Authors: Duan Qingyun , Schaake John C.
Published: November 2003

This paper presents a diagnostic approach to study the spatial and temporal variability of total water storage (TWS) properties of hydrologic basins. The approach utilizes a simple water balance equation based on the physical law of mass conservation. Thirty‐six years of monthly historical records of precipitation and streamflow discharge data were collected from 27 basins in the Arkansas‐Red River basin. Five different assumptions were made to estimate evapotranspiration. The study found that the assumption that considers both initial total water storage and precipitation amount in the current period provides the most consistent long‐term seasonal evapotranspiration, when compared to seasonal evapotranspiration derived from the atmospheric water budget in the Arkansas‐Red River basin. The TWS variability range has an apparent east‐west gradient and is highly correlated to climatological factors such as the ratio of annual precipitation and potential evapotranspiration and vegetation information. Wetter basins tend to have a larger TWS variability range than dry ones. The intra‐annual TWS variability range is small compared to year‐to‐year variability. This phenomenon is more noticeable for dry basins, implying that longer data sets are needed to study the water balance of dry regions. Another finding is that the TWS variability range is shown to be scale dependent, with intermediate‐scale‐area basins exhibiting larger variability than large‐scale‐area basin.
On the determination of atmospheric water vapor from GPS measurements
Authors: Hagemann Stefan , Bengtsson Lennart , Gendt Gerd
Published: November 2003

Surface‐based GPS measurements of zenith path delay (ZPD) can be used to derive vertically integrated water vapor (IWV) of the atmosphere. ZPD data are collected in a global network presently consisting of 160 stations as part of the International GPS Service. In the present study, ZPD data from this network are converted into IWV using observed surface pressure and mean atmospheric water vapor column temperature obtained from the European Centre for Medium‐Range Weather Forecasts' (ECMWF) operational analyses (OA). For the 4 months of January/July 2000/2001, the GPS‐derived IWV values are compared to the IWV from the ECMWF OA, with a special focus on the monthly averaged difference (bias) and the standard deviation of daily differences. This comparison shows that the GPS‐derived IWV values are well suited for the validation of OA of IWV. For most GPS stations, the IWV data agree quite well with the analyzed data indicating that they are both correct at these locations. Larger differences for individual days are interpreted as errors in the analyses. A dry bias in the winter is found over central United States, Canada, and central Siberia, suggesting a systematic analysis error. Larger differences were mainly found in mountain areas. These were related to representation problems and interpolation difficulties between model height and station height. In addition, the IWV comparison can be used to identify errors or problems in the observations of ZPD. This includes errors in the data itself, e.g., erroneous outlier in the measured time series, as well as systematic errors that affect all IWV values at a specific station. Such stations were excluded from the intercomparison. Finally, long‐term requirements for a GPS‐based water vapor monitoring system are discussed.
On the diffusivity in coastline dynamics
Authors: Falqués A.
Published: November 2003

The 1D diffusion equation for the dynamics of the coastline is revisited. It is found that the classical evaluation of the diffusivity coefficient over‐predicts it by a factor ranging from 1.25 up to infinity since the diffusivity may become zero while the classical prediction is always positive. The over‐prediction depends on wave steepness and wave incidence angle. It is larger for swell than for sea waves and it increases with increasing angle. For moderate angles it can easily be about a factor 10. Negative diffusivity occurs in case of large angles, consistent with the large angle morphodynamic instability.
Seawater intrusion through the oceanic crust and carbonate sediment in the Equatorial Pacific: Lithium abundance and isotopic evidence
Authors: You Chen‐Feng , Chan L.‐H. , Gieskes J. M. , Klinkhammer G. P.
Published: November 2003

Large‐scale lateral advection of seawater within the oceanic crust is thought to be the cause of low heat flow in the Equatorial Pacific. Until now supportive evidence is limited to reversals of B and δ11B, Ca, Mg, SO4−2, Sr and 87Sr/86Sr in sediment pore waters. Here we report new evidence from a detailed study of Li and its isotopes in sediment cores from ODP Sites 844 and 851. Carbonates at these sites were significantly recrystallized leading to large variations in Li and δ7Li in the sediments and associated pore waters. In addition to diagenetic effects, distinct reversals in lithium concentration and isotopic ratio toward modern seawater composition are observed in waters near the basaltic basement, lending further support to the seawater intrusion hypothesis. Three endmembers are identified in the pore waters: seawater, a diagenetically altered component, and evolved crustal fluid. The new lithium isotopic results underscore the importance of diagenetic artifacts in carbonate sediments.
Fluid acceleration effects on suspended sediment transport in the swash zone
Authors: Puleo J. A. , Holland K. T. , Plant N. G. , Slinn D. N. , Hanes D. M.
Published: November 2003

Suspended sediment concentrations and fluid velocities measured in the swash zone of a high‐energy steep beach were used to investigate the importance of fluid accelerations to suspended sediment transport. Swash flow acceleration was nearly constant at about one‐half downslope gravitational acceleration with two important exceptions. We observed strong, short‐lived periods of accelerating uprush at the beginning of the swash cycle and decelerating backwash at the end of the swash cycle (magnitudes of both approximately twice that of the expected downslope gravitational acceleration). Interestingly, spikes in suspended load followed the anomalies in acceleration in a way that was not apparent from the nearly symmetric (in magnitude) ensemble averaged velocity time series. Suspended load values were largest during accelerating uprush associated with the shoreward propagating turbulent bore or swash front. During backwash, suspended loads were generally not as large. Correspondingly, suspended sediment transport rates obtained from the sediment concentration and velocity measurements showed best comparisons with a modified sediment transport model that includes a physical mechanism for enhancing transport rates due to flow acceleration. The modified sediment transport model reduced the overall root‐mean square prediction error by up to 35% and shifted the predicted peak in uprush sediment transport rate earlier in the swash cycle, resulting in a better fit to the observations. These findings suggest that the inclusion of the acceleration term may account for physical mechanisms that include bore turbulence and horizontal pressure gradients typically associated with the accelerating portion of uprush.
North Pacific Intermediate Water response to a modern climate warming shift
Authors: Auad Guillermo , Kennett James P. , Miller Arthur J.
Published: November 2003

Oceanic observations and an isopycnal ocean model simulation are used to investigate the response of North Pacific Intermediate Water (NPIW) to atmospheric forcing associated with the well‐known 1976–1977 climate regime shift to a warm regime. The model reproduces numerous features of NPIW including distribution, depth, temperature, and salinity. Changes in NPIW associated with the climate shift in the California coastal region were strongly influenced by an anomalous poleward flow at depth (300–1100 m). This current transports old, high salinity, low oxygen intermediate waters from the northern tropics to the midlatitudes. For depths below the mixed layer, the model reproduces observed changes in salinity, nitrates, and, to some extent, oxygen, thus suggesting that advective/diffusive processes are dominant in determining their concentrations below 300 m, isolated from the surface effects of direct atmospheric forcing and biological processes. These changes are structurally similar to those induced by much larger, abrupt climate changes at the end of the last glacial episode.