bluuebunny/crossref_metadata_2025 huggingface dataset:
Allocation of offspring size and sex by female black ratsnakes
Authors: Blouin‐Demers Gabriel , Weatherhead Patrick J.
Published: December 2007

How females allocate resources to each offspring and how they allocate the sex of their offspring are two powerful potential avenues by which mothers can affect offspring fitness. Previous research has focussed extensively on mean offspring size, with much less attention given to variance in offspring size. Here we focussed on variation in offspring size in black ratsnakes, Elaphe obsoleta. We collected and hatched 105 clutches (1283 eggs) over 9 years. We predicted that females should lay larger eggs, or more variable eggs, when the environment is less predictable. We also predicted that females laying early or laying larger eggs should produce mostly sons because adult males are larger than adult female ratsnakes. The largest hatchling was more than twice the length and almost four times the mass of the smallest hatchling. Variation in offspring size was itself highly variable, with CVs in offspring mass among clutches ranging from 1% to 25%. With one exception, the variables we expected should influence variation in offspring size had little effect. We found that clutch size increased with maternal size and that egg size decreased with clutch size, but we found no evidence that variance in egg size among clutches increased as the season progressed or that females increased the mean size of their offspring the later in the season they laid their eggs. Females in better condition after they finish laying their eggs did produce larger eggs. There was no relationship between within‐clutch variation in egg size and laying date or mean egg size. Finally, sex ratio did not vary with mean egg size or hatching date. Given evidence that offspring size in snakes affects survival, selection should reduce variation in offspring size unless that variance enhances maternal fitness and yet we found little support for hypothesized advantages of varying offspring size.
Reproductive assurance through self‐fertilization does not vary with population size in the alien invasive plant Datura stramonium
Authors: Kleunen Mark van , Fischer Markus , Johnson Steven D.
Published: December 2007

Autonomous self‐fertilization is suggested to be associated with invasiveness in plants because it offers reproductive assurance when there is a shortage of suitable mates or pollinators. Given that shortages of mates and pollinators are a common cause of Allee effects in small plant populations, we predict that the benefits of self‐fertilization in terms of reproductive assurance should be greatest in small populations. We tested this idea for the invasive herb Datura stramonium, a self‐fertilizing species which is also cross‐pollinated to some extent by insects (mainly hawkmoths and honeybees). During two consecutive years, we studied 20 and 55 populations, respectively, of different sizes. Untreated flowers of D. stramonium showed high levels of fruit and seed set in all populations studied. Although, fruit and seed set were generally reduced by about 90% in flowers in which self‐fertilization was prevented through emasculation, this effect did not vary according to population size. By using a natural color (anthocyanin) dimorphism in 12 populations, we showed that the average outcrossing rate was low (1.3%) and that there was no relationship between outcrossing rate and population size. Pollen removal from flowers also did not vary according to population size, suggesting that the pollinator visitation rate is not lower in small populations. However, decreasing deviations of observed from expected fruit set with population size imply that small populations may have an increased chance of extinction due to demographic stochasticity. Overall, our results suggest that reproductive assurance through self‐fertilization in invasive plants may be important for all stages of population establishment, and not just in the founder population.
Contrasting effects of diversity on the temporal stability of plant populations
Authors: Ruijven Jasper van , Berendse Frank
Published: December 2007

Recent theoretical and empirical work suggests that diversity enhances the temporal stability of a community. However, the effect of diversity on the stability of the individual populations within the community remains unclear. Some models predict a decrease of population stability with diversity, whereas others suggest that diversity has a stabilizing effect on populations. Empirical evidence for either relationship between population stability and diversity is weak. The few studies that directly assessed the stability of populations reported contradicting results. We used a six‐year data‐set from a plant diversity experiment to examine the relationships between diversity and temporal stability of plant biomass. Our results show that stability increased with diversity at the community‐level, while the stability of populations, averaged over all species, decreased with diversity. However, when examining species separately we found positive, negative and neutral relationships between population stability and diversity. Our findings suggest that diversity may contribute to the stability of ecosystem services at the community level, but the effect of diversity on the stability of the individual populations within the community are generally negative. However, different species within the community may show strikingly different relationships between diversity and stability.
Phenotypic tradeoffs between egg number and egg size in three parasitic anisakid nematodes
Authors: Victoria Herreras M. , Montero Francisco E. , Marcogliese David J. , Antonio Raga J. , Balbuena Juan A.
Published: December 2007

Phenotypic tradeoffs between number and size of eggs were tested in three component populations of three marine anisakid nematodes:Anisakis simplex,Pseudoterranova decipiensandContracaecum osculatum. Body and uterine volumes (as proxies of female size), and egg number, mean egg volume and clutch volume (as descriptors of reproductive output) were measured in 50 females of each species. Evidence of a phenotypic tradeoff was detected only inA. simplex; the first time that has been found in a parasite population. Comparison of feasible values inferred from the van Noordwijk and de Jong's model and current data showed that interindividual variation in egg size was narrower than expected in the three populations. Structural constrictions in response to optimal allocation rules might account for this pattern. InP. decipiensandC. osculatumvariation in egg size was the lowest and independent of female size, suggesting that the tradeoff is absent, rather than being present but masked by unaccounted variables. Spatial constrictions imposed by uterine size seemed to play an important role determining the emergence of the tradeoffs. So factors accounting for the tradeoff inA. simplexare probably constructional rather than physiological. Individual variability in investment in clutch volume was similar to previous studies but variation in allocation between number and size of eggs was much smaller than that reported previously. Perhaps differences in life‐history strategies might explain this because the nematodes studied are either semelparous or short‐lived iteroparus organisms whereas previous data derive from long‐lived iteroparous ones. Despite the perception that parasites live in resource‐rich habitats, the present study indicates that patterns relating number and size of eggs might not differ much from those observed in free‐living populations and thus the same range of factors would operate in both types of organisms.
Global patterns of aquatic food chain length
Authors: Jake Vander Zanden M. , Fetzer William W.
Published: December 2007

Food chain length is a fundamental ecosystem property, and plays a central role in determining ecosystem functioning. Recent advances in the field of stable isotope ecology allow the estimation of food chain length (FCL) from stable nitrogen isotope (δ15N) data. We conducted a global literature synthesis and estimated FCL for 219 lake, stream, and marine ecosystems. Streams had shorter food chains (∼3.5 trophic levels) than marine and lake ecosystems (∼4.0 trophic levels). In marine systems, inclusion of marine mammals increased FCL by 2/3 of a trophic level. For each ecosystem type, estimates of FCL were normally distributed and spanned two full trophic levels. Comparison with published connectance food webs revealed similar mean FCL values, though stable isotope‐derived FCL estimates were less variable. At the global scale, FCL showed weak or no relationships with ecosystem size, mean annual air temperature, or latitude. Our study highlights the utility of stable isotopes for quantifying among‐system food web variability, and the application of this approach for assessing global‐scale patterns of food chain length.
Contrasting leaf age preferences of specialist and generalist stick insects (Phasmida)
Authors: Blüthgen Nico , Metzner Anika
Published: December 2007

Specialist and generalist herbivores may select for different types of plant defences or for different distribution of defences within a plant: e.g. between early and late stages of leaf maturation. The differentiation of age‐specific defences is particularly pronounced in tropical rain forests where young leaves are often produced year‐round, but effects on feeding choices of tropical herbivores are largely unknown. We compared feeding preferences of four species of tropical stick insects (Phasmida) between young or old leaves in dual choice experiments. Two phasmid species (Haaniella echinata, Lonchodes cultratolobatus) were highly polyphagous generalists. The other two species were classified as specialists, with Asceles margaritatus feeding mainly on Mallotus floribundus and M. miquelianus (Euphorbiaceae) and Dinophasma ruficornis mainly on Leea indica (Leeaceae) at the study site. Both specialists significantly preferred young leaves over old leaves of their respective host plants. In contrast, both generalists significantly preferred old leaves of the hosts of the specialist A. margaritatus. To reveal whether differential feeding choices were triggered by foliar chemistry, extracts (water, acetone, and hexane) of young leaves were applied to discs from old leaves and vice versa, and subjected to similar choice tests. For both Mallotus species, experimental results suggest that four chemical functions act in concert: (1) young leaves contain deterrents against generalists and (2) stimulants for specialists. Moreover, (3) old leaves contain deterrents against specialists and (4) stimulants for generalists. Deterrent compounds in young and old leaves, respectively, appeared in extracts using different solvents, suggesting the activity of multiple classes of secondary metabolites. Our study thus reveals that plant defences and herbivore offences are partly structured by leaf ontogeny and herbivore specialisation in a tropical plant‐herbivore system.
Turnover in an amphibian metacommunity: the role of local and regional factors
Authors: Werner Earl E. , Yurewicz Kerry L. , Skelly David K. , Relyea Rick A.
Published: December 2007

Ecologists have long realized that stable species richness values can mask rapid turnover in species composition. Because turnover occurs as a consequence of both local and regional processes, understanding the responsible factors provides insight on processes influencing community structure at different scales. Despite the insights to be gained from data on species turnover, they remain relatively uncommon. We present data on the interannual turnover in species composition of larval amphibian communities in 37 ponds over seven years. Species composition of a given pond community was highly dynamic; about half of the species that could be found breeding in a particular pond were actually present in a given year. All species participated in this community turnover, but to different degrees. Using a model selection approach, we show that a statistical model including local environmental factors (pond area, hydroperiod, and canopy cover) and pond connectivity on the landscape provided the best predictions of turnover. Averaged parameter estimates were significant for area, hydroperiod, and connectivity and these same variables were identified by hierarchical partitioning as having significant independent effects on turnover. Area and hydroperiod were negatively related to turnover, whereas connectivity was positively related to turnover. Additionally, the average fraction of years a species was present in a pond was positively correlated with average local population size, but even more strongly correlated with regional population size, suggesting both local and regional influences on turnover. Of the measured biotic factors (biomass of fish, invertebrate predators, anuran and caudate larvae), presence of fish was the only factor that significantly affected rates of turnover. Several mechanism could be responsible for changes in species composition (species extinctions, skipped breeding and movement of choruses), but extinctions appear to be the major cause of turnover. These results have important implications to understanding long‐term persistence of species on landscapes and the causes of patterns in species richness on environmental gradients.
Testing ecological and behavioral correlates of nest predation
Authors: Fontaine Joseph J. , Martel Mireille , Markland Helen M. , Niklison Alina M. , Decker Karie L. , Martin Thomas E.
Published: December 2007

Variation in nest predation rates among bird species are assumed to reflect differences in risk that are specific to particular nest sites. Theoretical and empirical studies suggest that parental care behaviors can evolve in response to nest predation risk and thereby differ among ecological conditions that vary in inherent risk. However, parental care also can influence predation risk. Separating the effects of nest predation risk inherent to a nest site from the risk imposed by parental strategies is needed to understand the evolution of parental care. Here we identify correlations between risks inherent to nest sites, and risk associated with parental care behaviors, and use an artificial nest experiment to assess site‐specific differences in nest predation risk across nesting guilds and between habitats that differed in nest predator abundance. We found a strong correlation between parental care behaviors and inherent differences in nest predation risk, but despite the absence of parental care at artificial nests, patterns of nest predation risk were similar for real and artificial nests both across nesting guilds and between predator treatments. Thus, we show for the first time that inherent risk of nest predation varies with nesting guild and predator abundance independent of parental care.
How to test an inclusive fitness hypothesis – worker reproduction and policing as an example
Authors: Helanterä Heikki
Published: December 2007

The importance of relatedness in explaining social behaviour continues to be under debate. In this commentary, I use two recent comparative studies as examples to discuss how testing kin selection hypotheses in a comparative across‐species setting both shows that relatedness explanations are not in trouble, and points out direction for further empirical studies.
How should a dendrogram‐based measure of functional diversity function? A rejoinder to Petchey and Gaston
Authors: Podani János , Schmera Dénes
Published: December 2007

This paper is a response to Petchey and Gaston's criticism of our previous paper on the measurement of dendrogram‐based functional diversity. In contrast to their suggestions, we insist that Euclidean distance is unsuitable to the analysis of variables with mixed scale types and maintain our earlier view that both the distance function and the clustering method can influence the dendrogram‐based measure of functional diversity. We propose an extension of Gower's formula to accommodate nominal traits with non‐exclusive categories and emphasize the necessity of the methodological standardization of functional diversity measures.
Insulin‐like growth factor‐binding protein‐1: an evolutionarily conserved fine tuner of insulin‐like growth factor action under catabolic and stressful conditions
Authors: Kajimura S. , Duan C.
Published: December 2007

The insulin‐like growth factor‐binding proteins (IGFBPs) are evolutionarily conserved components of the insulin‐like growth factor (IGF) system. The six forms of IGFBPs (IGFBP‐1–6) bind the IGF ligands (IGF‐1 and ‐2) with high affinity and regulate the IGFs available to their receptors, therefore providing additional flexibilities in regulating IGF signalling. IGFBP‐1, the first identified member of the IGFBP family is highly inducible under a variety of catabolic conditions, such as food deprivation, malnutrition, stress, injury and hypoxia. Recent in vivo studies have indicated that the induced IGFBP‐1 serves as a molecular switch by restricting IGF signalling and diverts the limited energy resources away from growth and development towards those metabolic processes essential for survival. This article reviews the recent understandings of the molecular basis of IGFBP‐1 regulation and its biological functions, as revealed through research in mammalian and fish models.
Demonstration and implications of habitat‐specific chemical signatures in otoliths of juvenile summer flounder (Paralichthys dentatus Linnaeus) in North Carolina
Authors: Kellison G. T. , Taylor J. C.
Published: December 2007

The objective of this pilot study was to determine if otolith signatures of juvenile summer flounder Paralichthys dentatus (Linnaeus) were differentiable between beach and marsh habitat types within two North Carolina (NC), U.S.A., estuarine systems. Elemental signatures were differentiable between habitats in both systems, and in one system at smaller spatial scales (<5 km) than have been reported for any estuarine species using otolith microchemistry. These results indicate the potential for using summer flounder otolith elemental analysis to assess the nursery role of habitats within NC estuaries.
Assessment of young yellow European eel Anguilla anguilla L. exposure to a CYP1A1 inducer by the quantification of increase in hepatic CYP1A1 mRNA using real‐time RT‐PCR
Authors: Aubry E. , Cagnon C. , Lalanne Y. , Mouchès C.
Published: December 2007

Young European eels were exposed to β‐naphthoflavone (βNF). The CYP1A1 mRNA hepatic levels, measured by real‐time reverse transcription polymerase chain reaction, were correlated to the concentration of βNF and the time of exposure so that it can be used as a biomarker of European eel exposure to a CYP1A1 inducer.
Genetic and biogeographic relationships of the racer goby Neogobius gymnotrachelus (Gobiidae: Teleostei) from introduced and native Eurasian locations
Authors: Ohayon J. L. , Stepien C. A.
Published: December 2007

The racer goby Neogobius gymnotrachelus, along with several other neogobiin fishes, has been spreading north and west from its native Ponto‐Caspian range for the past two decades via shipping and canals. It has been predicted as a likely future invader of the North American Great Lakes, where it would join its neogobiin relatives – the round and freshwater tubenose gobies. The present study is the first to analyse the population genetic and biogeographic relationships of the racer goby, establishing a baseline to aid interpretation of its future spread patterns and likely donor‐recipient population relationships. The mitochondrial DNA cytochrome b gene was sequenced from representative areas of the racer goby’s range, including rivers of the northern Black Sea and areas of spread upstream in the Danube River and outside the Ponto‐Caspian region to the Vistula River in Poland. Results discerned nine haplotypes, with few shared among drainages of native rivers and most sites housing unique alleles. Racer goby populations significantly diverged among watersheds, supporting historic low migration and little non‐anthropogenic gene flow. The Dnieper River was identified as a likely donor source for the Vistula River colonization, where appreciable variability suggests a relatively large number of founding genotypes.
Diversity of European spined loaches (genus Cobitis L.): an update of the geographic distribution of the Cobitis taenia hybrid complex with a description of new molecular tools for species and hybrid determination
Authors: Janko K. , Flajšhans M. , Choleva L. , Bohlen J. , ŠLechtová V. , Rábová M. , Lajbner Z. , ŠLechta V. , Ivanova P. , Dobrovolov I. , Culling M. , Persat H. , Kotusz J. , Ráb P.
Published: December 2007

Although the unique features of asexual reproduction and hybridization among European spined loaches (genus Cobitis) have recently attracted the attention of conservation biologists, faunists and evolutionary biologists, the research has suffered from uncertain identification of specimens and their genomes because of the extreme morphological similarity of all the species within the hybrid complex. In this article, a Europe‐wide study is reported, which was performed on samples collected by several research teams. Several complementary methodologies, such as allozyme analysis, karyotyping, flow cytometry and DNA sequencing allowed us to confirm or reject the existence of all previously reported species and their hybrids as well as to uncover several new hybrid biotypes. The biogeography of all the known biotypes, that is, parental species and hybrid biotypes, has been summarized here and the taxonomic position of two undescribed putative species mentioned in previous publications has been established. New polymerase chain reaction restriction fragment length polymorphism markers for species determination have further been developed and applied, which would allow the unambiguous identification of parental species and their genomes in the known hybrid biotypes within the complex.
Genetic structure of masu salmon (Oncorhynchus masou) populations in Hokkaido, northernmost Japan, inferred from mitochondrial DNA variation
Authors: Kitanishi S. , Edo K. , Yamamoto T. , Azuma N. , Hasegawa O. , Higashi S.
Published: December 2007

Genetic structure of masu salmonOncorhynchus masoupopulations in Hokkaido was examined by analysing mtDNA NADH dehydrogenase subunit 5 gene (561 bp) of 382 individuals collected from 12 rivers, in which there were no records of artificial release. Analysis of molecular variance showed that between groups level and between populations within‐group level explained eachc.10% of genetic variance. In neighbour‐joining tree, four populations located in southern Hokkaido were clustered into a single group; however, other populations did not form any clear clusters. Fu’sFS, Tajima’sDand a mismatch distribution test indicated a sudden expansion of population in the entire population of Hokkaido and the northernmost population of Chiraibetsu, which was genetically close to the southern Hokkaido group. The Sea of Japan and southern rivers, including those of southern Hokkaido, seem to have served as refugia for masu salmon during glacial periods, and their dispersal and straying in interglacial periods affected the genetic structure of masu salmon populations in Hokkaido.
Verification of meiotic gynogenesis in Siberian sturgeon (Acipenser baeri Brandt) using microsatellite DNA and cytogenetical markers
Authors: Fopp‐Bayat D.
Published: December 2007

Diploid gynogenesis was induced in Siberian sturgeon Acipenser baeri using ultra violet (UV)‐irradiated bester (Huso huso ×Acipenser ruthenus) sperm. The higher survival rate of meiotic diploids was noted after 1350 ergs mm−2 UV irradiation. A total of 80 meiotic diploids of known parentage from two different experimental treatments were screened using microsatellite DNA and cytogenetical analysis, and uniparental transmission in meiotic diploids was confirmed.
Engineering plant oils as high‐value industrial feedstocks for biorefining: the need for underpinning cell biology research
Authors: Dyer John M. , Mullen Robert T.
Published: December 2007

Plant oils represent renewable sources of long‐chain hydrocarbons that can be used as both fuel and chemical feedstocks, and genetic engineering offers an opportunity to create further high‐value specialty oils for specific industrial uses. While many genes have been identified for the production of industrially important fatty acids, expression of these genes in transgenic plants has routinely resulted in a low accumulation of the desired fatty acids, indicating that significantly more knowledge of seed oil production is required before any future rational engineering designs are attempted. Here, we provide an overview of the cellular features of fatty acid desaturases, the so‐called diverged desaturases, and diacylglycerol acyltransferases, three sets of enzymes that play a central role in determining the types and amounts of fatty acids that are present in seed oil, and as such, the final application and value of the oil. Recent studies of the intracellular trafficking, assembly and regulation of these enzymes have provided new insights to the mechanisms of storage oil production, and suggest that the compartmentalization of enzyme activities within specific regions or subdomains of the ER may be essential for both the synthesis of novel fatty acid structures and the channeling of these important fatty acids into seed storage oils.
Why the South African NQF Failed: lessons for countries wanting to introduce national qualifications frameworks
Authors: ALLAIS STEPHANIE MATSELENG
Published: December 2007

This article examines the South African National Qualifications Framework as a case study of a particular approach to the design of qualifications frameworks, which revolves around the specification of learning outcomes separate from educational institutions or programmes. It shows how an outcomes‐led qualifications framework was seen as a desirable policy intervention by educationalists and reformers across the political spectrum, as outcomes were thought to be a mechanism for improving the quality and quantity of education as well as its relevance to the economy and society, for increasing access to education, and for democratising education. All these claims are based on the idea that outcomes statements are transparent. The article demonstrates that outcomes‐based qualifications cannot provide the clear, unambiguous, and explicit statements of competence that would be required for everyone to know what it is that the bearer of a qualification can do. This lack of transparency leads to a further specification of outcomes. This in turn leads to a downward spiral of specification, which never reaches transparency, and an upward spiral of regulations, which is also caught in the logical problem of the downward spiral of specification. This model is not just unnecessary, but could in fact undermine the provision of education. The article suggests that while this type of model appears attractive particularly to poor countries, it is in these countries that it is likely to do the most damage.
Making Haste Slowly: the evolution of a unified qualifications framework in Scotland
Authors: RAFFE DAVID
Published: December 2007

The Scottish Credit and Qualifications Framework is often claimed to be a success and an example to other countries. However, if other countries wish to learn from this example they should not only study the current framework; they should also examine the sequence of policy reforms, over a quarter of a century, through which it developed. The article traces the history of these reforms and shows how they incrementally created the conditions for a successful comprehensive qualifications framework. It argues that the main drivers for change have been internal to the education system, rather than external economic, social or ideological pressures, and the main barriers have been institutional and political rather than epistemological. There were specific reasons why it took such a long time to develop the Scottish framework, but in any country it takes many years to establish the conditions for a successful comprehensive framework.
Qualifications Frameworks: some conceptual issues
Authors: YOUNG MICHAEL
Published: December 2007

The aim of this article is to contribute to realising the progressive and democratic opportunities that National Qualifications Frameworks (NQFs) can offer. In doing so it will be critical of many of the ways that NQFs have been interpreted to date and the claims that have been made for them. The article has six sections. Section 1 considers some of the reasons for the recent growth of interest in NQFs. Section 2 is concerned with the widely shared goals of NQFs and some of the contradictions and problems that they involve. Section 3 discusses the very different forms that NQFs can take. Section 4 examines a number of issues that underlie all approaches to qualifications but are made more explicit by qualification frameworks and concludes by questioning the much lauded claim that NQFs can promote and accredit informal learning. The concluding section considers the longer term implications for the future of NQFs of the earlier analysis.
The Implementation of New Technologies Through a Participative Approach
Authors: García‐Arca Jesús , Prado‐Prado J. Carlos
Published: December 2007

Implementation projects of information systems, particularly in the logistics field, are usually long, complex processes requiring a good deal of resources. As an alternative to an exclusively technical viewpoint, the contribution by the users themselves to the design and implementation of these information systems may facilitate better final results. With this participative approach in mind, this paper proposes a methodology for implementing information and communication technologies (ICTs) that includes the recommendations put forward in the literature, which also involves the authors of the paper themselves as agents for change in companies, in line with the ‘action research’ approach. In order to illustrate the potential of this methodology, which may be of interest to the academic and professional world, analysis is made of the successful cases of two Spanish companies in the food sector that have recently applied this methodology in ICT implementation.
Role Models for Radical Innovations in Times of Open Innovation
Authors: Gemünden Hans Georg , Salomo Sören , Hölzle Katharina
Published: December 2007

In this paper, we study the influence of innovator roles in highly innovative ventures. In order to obtain a differentiated picture we take into account the degree of innovativeness as a moderating variable. To test our hypotheses we use a sample of 146 highly innovative new product development projects. We choose a rigorous sampling design and apply state‐of‐the‐art measures for the degree of innovativeness. Furthermore, we apply multi‐trait‐multi‐method methodology (MTMM) to enhance the validity of our study. The results show that innovator roles have a strong influence on innovation success but these influences are positively and negatively moderated by innovativeness. The moderating influences depend on the type of innovativeness. Remarkably, with increasing technological innovativeness innovator roles which create inter‐organizational links with the outside world appear to be more important than intra‐organizational linker roles, and support from high‐ranked organizational members turns out to have a significant negative effect on project success with higher degrees of technological innovativeness. Possible explanations for these findings are discussed and consequences for innovation research and innovation management are shown.
The Implementation of Best Practices: Process and Performance Effects
Authors: Laugen Bjørge Timenes , Boer Harry
Published: December 2007

Much has been written about best practices and world class manufacturing in recent years. Various practices and improvement programmes have been suggested as best practices, assuming that their adoption would to lead to higher performance. The implementation process of these practices is, however, often neglected in the literature and, hence, relatively poorly understood. The purpose of this article is to provide insight into that process and how different implementation approaches influence performance. An analysis of the implementation of a range of manufacturing action programmes in two companies showed that a broad and incremental implementation approach initially leads to reduced performance followed by a gradual improvement as larger parts of the programmes are institutionalized. A ‘big bang’ implementation approach does not seem to lead to deterioration in performance.
Continuous and Discontinuous Innovation: Overcoming the Innovator Dilemma
Authors: Corso Mariano , Pellegrini Luisa
Published: December 2007

Challenged by competition pressures and unprecedented pace of change, firms can no longer choose whether to concentrate on the needs of today's customers or on the anticipation of those of tomorrow: they must be excellent in both. This requires managing two related balancing acts: on the one side, being excellent in both exploitation and exploration of their capabilities and, on the other side, being excellent in managing both incremental and radical innovation. These balances are critical since exploitation and exploration, on the one side, and incremental and radical innovation, on the other, require different approaches that have traditionally been considered difficult to combine within the same organization. Working on evidence and discussion from the 7th CINet Conference held in Lucca (Italy) in 2006, this Special Section is aimed at contributing to theory and practice on these two complex balancing acts that today represent a hot issue in innovation management.
Cyberbullying: Another main type of bullying?
Authors: SLONJE ROBERT , SMITH PETER K.
Published: December 2007

Cyberbullying has recently emerged as a new form of bullying and harassment. 360 adolescents (12–20 years), were surveyed to examine the nature and extent of cyberbullying in Swedish schools. Four categories of cyberbullying (by text message, email, phone call and picture/video clip) were examined in relation to age and gender, perceived impact, telling others, and perception of adults becoming aware of such bullying. There was a significant incidence of cyberbullying in lower secondary schools, less in sixth‐form colleges. Gender differences were few. The impact of cyberbullying was perceived as highly negative for picture/video clip bullying. Cybervictims most often chose to either tell their friends or no one at all about the cyberbullying, so adults may not be aware of cyberbullying, and (apart from picture/video clip bullying) this is how it was perceived by pupils. Findings are discussed in relation to similarities and differences between cyberbullying and the more traditional forms of bullying.
Intellectual function in children with teacher reported language problems
Authors: LUNDERVOLD A. J. , POSSERUD M. , SØRENSEN L. , GILLBERG C.
Published: December 2007

We predicted that teacher reported language problems are associated with low IQ, even when gender and behavior‐emotional disorders are controlled for. All subjects were participants in a population based study. In stage 1, teachers completed a questionnaire containing four items pertaining to language function. A case‐control sample (n= 294) was assessed using WISC‐III and Kiddie‐SADS‐PL. A child was defined with “language problems” (LP) if s/he obtained a score indicating severe problems on at least one item. Teacher reported LP was found in 9.9% of the population sample and 20.7% of the case‐control sample, with a three‐fold higher risk for boys than girls. The LP group obtained significantly lower scores on all WISC‐III factors compared with the non‐LP group. The differences were not accounted for by the presence of behavioral‐emotional disorders. When primary school teachers report LP, further assessment of the child's cognitive function is warranted.
Bootstrapping the Local Periodogram of Locally Stationary Processes
Authors: Sergides Marios , Paparoditis Efstathios
Published: December 2007

Abstract. Locally stationary processes are non‐stationary stochastic processes the second‐order structure of which varies smoothly over time. In this paper, we develop a method to bootstrap the local periodogram of a locally stationary process. Our method generates pseudo local periodogram ordinates by combining a parametric time and non‐parametric frequency domain bootstrap approach. We first fit locally a time varying autoregressive model so as to capture the essential characteristics of the underlying process. A locally calculated non‐parametric correction in the frequency domain is then used so as to improve upon the locally parametric autoregressive fit. As an application, we investigate theoretically the asymptotic properties of the bootstrap method proposed applied to the class of local spectral means, local ratio statistics and local spectral density estimators. Some simulations demonstrate the ability of our method to give accurate estimates of the quantities of interest in finite sample situations and an application to a real‐life data‐set is presented.
VISION AS REVISION: RANKE AND THE BEGINNING OF MODERN HISTORY
Authors: BRAW J. D.
Published: December 2007

It is widely agreed that a new conception of history was developed in the early nineteenth century: the past came to be seen in a new light, as did the way of studying the past. This article discusses the nature of this collective revision, focusing on one of its first and most important manifestations: Ranke's 1824 Geschichten der romanischen und germanischen Völker. It argues that, in Ranke's case, the driving force of the revision was religious, and that, subsequently, an understanding of the nature of Ranke's religious attitude is vital to any interpretation of his historical revision. Being aesthetic‐experiential rather than conceptual or “positive,” this religious element is reflected throughout Ranke's enterprise, in source criticism and in historical representation no less than in the conception of cause and effect in the historical process. These three levels or aspects of the historical enterprise correspond to the experience of the past, and are connected by the essence of the experience: visual perception. The highly individual character of the enterprise, its foundation in sentiments and experiences of little persuasive force that only with difficulty can be brought into language at all, explains the paradoxical nature of the Rankean heritage. On the one hand, Ranke had a great and lasting impact; on the other hand, his approach was never re‐utilized as a whole, only in its constituent parts—which, when not in the relationship Ranke had envisioned, took on a new and different character. This also suggests the difference between Ranke's revision and a new paradigm: whereas the latter is an exemplary solution providing binding regulations, the former is unrepeatable.
THE “INS” AND “OUTS” OF HISTORY: REVISION AS NON‐PLACE
Authors: HUGHES‐WARRINGTON MARNIE
Published: December 2007

Revision in history is conventionally characterized as a linear sequence of changes over time. Drawing together the contributions of those engaged in historiographical debates that are often associated with the term “revision,” however, we find our attention directed to the spaces rather than the sequences of history. Contributions to historical debates are characterized by the marked use of spatial imagery and spatialized language. These used to suggest both the demarcation of the “space of history” and the erasure of existing historiographies from that space. Bearing these features in mind, the essay argues that traditional, temporally oriented explanations for revision in history, such as Thomas S. Kuhn's Structure of Scientific Revolutions, miss the mark, and that a more promising line of explanation arises from the combined use of Michel Foucault's idea of “heterotopias” and Marc Augé's idea of “non‐places.” Revision in history is to be found where writers use imagery to move readers away from rival historiographies and to control their movement in the space of history toward their desired vision. Revision is thus associated more with control than with liberation.
REVISIONISM IN SOVIET HISTORY
Authors: FITZPATRICK SHEILA
Published: December 2007

This essay is an account of the “revisionism” movement of the 1970s and 1980s in Soviet history, analyzing its challenge to the totalitarian model in terms of Kuhnian paradigm shift. The focus is on revisionism of the Stalin period, an area that was particularly highly charged by the passions of the Cold War. These passions tended to obscure the fact that one of the main issues at stake was not ideological but purely disciplinary, namely a challenge by social historians to the dominance of political history. A similar challenge, this time against the dominance of social history on behalf of cultural history, was issued in the 1990s by “post‐revisionists.” Although I was a participant in the battles of the 1970s, the essay is less a personal account than a case‐based analysis of the way disciplinary orthodoxies in the social sciences and humanities are established and challenged, and why this happens when it does. In the case of Soviet history, I argue that new data and external events played a surprisingly small role, and generational change a large one.
Prednisone vs. Placebo in Withdrawal Therapy Following Medication Overuse Headache
Authors: Pageler L , Katsarava Z , Diener HC , Limmroth V
Published: December 2007

This proof-of-concept study evaluated the efficacy of prednisone for the treatment of withdrawal symptoms in patients with medication overuse headache (MOH) in a randomized, placebo-controlled, double-blind design. Twenty patients were randomized and underwent in-patient withdrawal therapy. The total number of hours with severe or moderate headache within the first 72 and 120 h was significantly lower in the prednisone group. The results show that prednisone might be effective in the treatment of medication withdrawal headache.
Tfm‐AR modulates the effects of ApoE4 on cognition
Authors: Rizk‐Jackson Angela , Robertson Jennifer , Raber Jacob
Published: December 2007

Female mice are more susceptible to apolipoprotein E (apoE4)‐induced cognitive deficits than male mice. These deficits can be antagonized by stimulating androgen receptors (ARs). To determine the role of AR in the cognitive effects of apoE4, we backcrossed mutant mice with a naturally occurring defect in the AR [testicular feminization mutant (tfm)] onto the Apoe−/− background to eliminate mouse apoE gene resulting in non‐functional AR, and crossed the tfm/Apoe−/− female mice with apoE4 transgenic male mice. We behaviorally compared Apoe−/−, apoE4, tfm, and tfm/apoE4 male mice. Apoe−/−, apoE4, and tfm mice showed hippocampus‐dependent novel location recognition but tfm/apoE4 mice did not. In contrast, all groups showed hippocampus‐independent novel object recognition. Hippocampus‐dependent learning and memory were also assessed in the water maze. In the water maze probe trial following the second day of hidden platform training, Apoe−/− and apoE4 mice showed spatial memory retention, but tfm and tfm/ApoE4 mice did not. In the water maze, probe trial following the third day of hidden platform training, Apoe−/−, apoE4, and tfm/Apoe−/− mice showed spatial memory retention, but tfm mice did not. These data support an important role for AR in protecting against the detrimental effects of apoE4 on hippocampus‐dependent learning and memory.
Effects of Alcohol Intoxication and Victimization History on Women's Sexual Assault Resistance Intentions: The Role of Secondary Cognitive Appraisals
Authors: Stoner Susan A. , Norris Jeanette , George William H. , Davis Kelly Cue , Masters N. Tatiana , Hessler Danielle M.
Published: December 2007

This study used an experimental paradigm to investigate the role of secondary cognitive appraisals in women's sexual assault resistance and whether these appraisals mediated influences of alcohol and prior victimization. After consuming a beverage (control, placebo, moderate, or high dose), 351 women projected themselves into a simulated interaction with a sexually aggressive man. Four types of secondary appraisals (shock at the man's behavior, concern about his feelings, uncertainty in the situation, conflict about what to do) and three resistance strategies (assertive, polite, passive) were examined. Path modeling revealed that, as expected, intoxication and prior sexual victimization influenced secondary appraisals, which in turn influenced intended resistance. Prior adult sexual assault (ASA) and childhood sexual abuse (CSA) also had direct effects: ASA negatively predicted assertive resistance and CSA positively predicted passivity. Findings suggest that secondary appraisals are key targets for intervention to facilitate effective resistance, thereby reducing the risk of adult sexual victimization.
Revising the SES: A Collaborative Process to Improve Assessment of Sexual Aggression and Victimization
Authors: Koss Mary P. , Abbey Antonia , Campbell Rebecca , Cook Sarah , Norris Jeanette , Testa Maria , Ullman Sarah , West Carolyn , White Jacquelyn
Published: December 2007

The Sexual Experiences Survey (SES) assesses victimization and perpetration of unwanted sexual experiences (e.g., Koss, Gidycz, & Wisniewski, 1987 ). Revised versions of the SES that resulted from the work of the SES Collaboration are now available. This article reviews weaknesses of the SES that were identified, strengths that were preserved, and methodological considerations in the measurement of unwanted sexual experiences that informed the revisions. The primary changes include: more behavioral specificity; conversion to gender neutrality; full crossing of unwanted acts and coercive tactics; and revised and updated wording for assessing consent, alcohol-related incidents, unwanted acts, and coercive tactics. For illustration, the full text of the revised victimization version and its scoring rules are provided. The article concludes with suggestions for future research. These suggestions aim to involve researchers in a coordinated agenda to develop data that clarify methodological questions and contribute to continued improvement in assessing sexual victimization and perpetration.
Body Dissatisfaction and Disordered Eating among College Women in China, South Korea, and the United States: Contrasting Predictions from Sociocultural and Feminist Theories
Authors: Jung Jaehee , Forbes Gordon B.
Published: December 2007

Body dissatisfaction and disordered eating were compared across groups of college women from China ( n = 109), South Korea ( n = 137), and the United States ( n = 102). Based on cultural differences in the amount of exposure to Western appearance standards, particularly the thin-body ideal, sociocultural theory ( Thompson, Heinberg, Altabe, & Tantleff-Dunn, 1999 ) would predict that body dissatisfaction and disordered eating would be highest in the U.S. sample and lowest in the Chinese sample. In contrast, based on the speed and pervasiveness of changes in women's roles, feminist theory ( Bordo, 1993 ; Jeffreys, 2005 ) would predict that body dissatisfaction and disordered eating would be highest in the Korean sample and lowest in the U.S. sample. Multidimensional measures indicated the highest levels of body dissatisfaction and disordered eating in the Korean sample and the lowest levels in the U.S. sample, indicating that predictions derived from feminist theory were a better fit to the data than predictions derived from sociocultural theory. Results indicated that theoretical understandings of body dissatisfaction must recognize not only differences between Western and non-Western cultures, but also differences among non-Western cultures.