bluuebunny/crossref_metadata_2025 huggingface dataset:
Between‐species differences in demographic responses to temperature of coexisting cladocerans
Authors: RAMOS‐JILIBERTO RODRIGO , ARÁNGUIZ‐ACUÑA ADRIANA
Published: October 2007

Abstract  In this work we report on the seasonal trends of abundances in terms of temperature exposure for four coexisting cladoceran species (Daphnia ambigua (Daphniidae), Ceriodaphnia dubia (Daphniidae), Diaphanosoma chilense (Sididae) and Moina micrura (Moinidae)) from a Chilean temperate lake. In order to compare the demographic response to temperature, we used life table experiments to parameterize matrix models for the four species at four fixed temperatures. From these life table response experiments we assessed the effects of temperature, species and their interaction on the variation in growth rate, as well as the contribution of juvenile survival, adult survival, fertility and age at first reproduction to the changes in growth rate. Our results showed interspecific differences in the effect of temperature on the growth rate. Species that present higher field abundance at lower temperature also exhibited, under controlled experiments, higher growth rates at low temperature and lower growth rates at high temperature, relative to the additive model. Conversely, species with higher abundances during the warmer seasons exhibited higher growth rates at higher experimental temperatures and lower growth rates at lower temperatures, relative to the additive model. The vital rates that most contributed to the variation in growth rate were age at first reproduction and fertility. Our growth rate estimates matched predictions of the metabolic ecology model.
Direct and indirect effects of climate on decomposition in native ecosystems from central Argentina
Authors: PÉREZ‐HARGUINDEGUY NATALIA , DÍAZ SANDRA , VENDRAMINI FERNANDA , GURVICH DIEGO E. , CINGOLANI ANA M. , GIORGIS MELISA A. , CABIDO MARCELO
Published: October 2007

Abstract Climate affects litter decomposition directly through temperature and moisture, determining the ecosystem potential decomposition, and indirectly through its effect on plant community composition and litter quality, determining litter potential decomposition. It would be expected that both the direct and indirect effects of climate on decomposition act in the same direction along gradients of actual evapotranspiration (AET). However, studies from semiarid ecosystems challenge this idea, suggesting that the climatic conditions that favour decomposition activity, and the consequent ecosystem potential decomposition, do not necessarily lead to litter being easier to decompose. We explored the decomposition patterns of four arid to subhumid native ecosystems with different AET in central‐western Argentina and we analysed if ecosystem potential decomposition (climatic direct effect), nutrient availability and leaf litter potential decomposition (climatic indirect effect) all increased with AET. In general, the direct effect of climate (AET) on decomposition (i.e. ecosystem potential decomposition), showed a similar pattern to nutrient availability in soils (higher for xerophytic and mountain woodlands and lower for the other ecosystems), but different from the pattern of leaf litter potential decomposition. However, the range of variation in the ecosystem potential decomposition was much higher than the range of variation in litter potential decomposition, indicating that the direct effect of climate on decomposition was far stronger than the indirect effect through litter quality. Our results provide additional experimental evidence supporting the direct control of climate over decomposition, and therefore nutrient cycling. For the ecosystems considered, those with the highest AET are the ecosystems with the highest potential decomposition. But what is more interesting is that our results suggest that the indirect control of climate over decomposition through vegetation characteristics and decomposability does not follow the same trend as the direct effect of climate. This finding has important implications in the prediction of the effects of climate change on semiarid ecosystems.
Pinus radiata invasion in Australia: Identifying key knowledge gaps and research directions
Authors: WILLIAMS MOIRA C. , WARDLE GLENDA M.
Published: October 2007

Abstract  Early recognition of plant invaders has been widely identified as the key to their successful management and yet too often species are only noticed and receive adequate attention once they have become widespread and control has become difficult and costly. Slow growing species are at particular risk of being overlooked, despite their ability to cause significant ecological damage. One such species, Pinus radiata (Monterey pine), has spread from large commercial plantations into native vegetation across the southern hemisphere. Here we review the status of P. radiata invasion in Australia, a country where the species has successfully naturalized but remains an invader of only low‐level concern. Patterns of spread in Australia mirror those in New Zealand and South Africa, two countries where invasive pines are considered major threats to biodiversity. While many areas adjacent to plantations remain free from invasion, dense infestations have occurred at several sites in areas of high conservation value demanding the implementation of adequate control measures. Expansion of Australia's plantation estate and increasing human disturbance of natural areas surrounding plantations will increase the likelihood and extent of invasion. Continued monitoring of wildling populations will determine the ability of pines to dominate native eucalypt forest and will provide insight into broader ideas of community invasibility.
Climate‐driven fluctuations in surface‐water availability and the buffering role of artificial pumping in an African savanna: Potential implication for herbivore dynamics
Authors: CHAMAILLÉ‐JAMMES SIMON , FRITZ HERVÉ , MURINDAGOMO FELIX
Published: October 2007

Abstract  In arid and semiarid environments surface‐water strongly constrains the distribution and abundance of large herbivores during the dry season. Surprisingly, we know very little about its variability in natural ecosystems. Here we used long‐term data on the dry‐season occurrence of water at individual waterholes to model the surface‐water availability across Hwange National Park, Zimbabwe, under contrasted climatic and management scenarios. Without artificial pumping only 19.6% of the park occurred within 5 km of water under average climatic conditions. However surface‐water availability was strongly influenced by annual rainfall, and over 20 years the variability of the surface area of the park occurring within 5 km of water was slightly larger than the variability of rainfall. This contrasts with the usual buffered response of vegetation production to rainfall fluctuations, and suggests that the variability in dry‐season foraging range determined by surface‐water availability could be the main mechanism regulating the population dynamics of large herbivores in this environment. Artificial pumping increased surface‐water availability and reduced its variability over time. Because changes in surface‐water availability could cause the greatest changes in forage availability for large herbivores, we urge ecologists to investigate and report on the variability of surface‐water in natural ecosystems, particularly where rapid climate changes are expected.
Fire frequency regulates tussock grass composition, structure and resilience in endangered temperate woodlands
Authors: PROBER SUZANNE M. , THIELE KEVIN R. , LUNT IAN D.
Published: October 2007

Abstract  The importance of disturbance for regulating the structure and diversity of grassy ecosystems is widely recognized, but disturbance‐mediated interactions between grassland composition and grassland resilience, and consequent implications for conservation management, are less well documented. We established replicated burning, mowing and (non‐livestock) grazing regimes in two contrasting grassy woodland remnants in south‐eastern Australia, and monitored the dynamics and resilience of the matrix‐forming tussock grasses, Poa sieberiana (Poa) and Themeda australis (Themeda), over 12 years. Introduction of frequent burning to a Poa‐dominated understorey in a rarely burnt woodland enhanced dominance by Themeda, and conversely, reduced fire frequency in a frequently burnt Themeda grassland substantially increased Poa abundance. Burning was potentially detrimental in the Poa‐dominated woodland, but sward resilience (recovery after the 2002 burn) increased as Themeda increased with repeated burning. By contrast, the Themeda grassland was resilient to 4‐ and 8‐yearly burning, but biennial burning led to poor resilience and high tussock mortality under drought conditions. Contrary to other mesic grasslands, cessation of burning had not caused sward collapse by 14 years post‐fire despite high litter accumulation, potentially due to compensatory growth of Poa, lower site productivity and drought. Biennial mowing without slash removal was similar to 4‐yearly burning in effects, while exclusion from kangaroo and rabbit grazing significantly increased sward biomass and contributed to increased Poa cover and inflorescence production. We conclude that functional complementarity associated with mixed dominants enhances resilience to variable disturbance regimes, and that below certain thresholds of abundance of each dominant, this resilience declines. Conservation management of Themeda–Poa ecosystems should thus aim to maintain an effective balance of these dominants.
Selection of habitat components by two species of agamid lizards in sandridge desert, central Australia
Authors: DALY BENJAMIN G. , DICKMAN CHRIS R. , CROWTHER MATHEW S.
Published: October 2007

Abstract  We studied the use and selection of habitat components by two species of agamid (dragon) lizards in the Simpson Desert, Queensland, Australia. Both the military dragon (Ctenophorus isolepis) and central netted dragon (Ctenophorus nuchalis) were captured in pitfall traps surrounded by areas of open sand, but the mean coverage of spinifex (Triodia basedowii) was greater (35%) around traps capturing C. isolepis than around those capturing its congener (approx. 8%). Direct observations of free‐ranging lizards confirmed that C. isolepis spent most time in, or within 30 cm of, spinifex hummocks, whereas C. nuchalis primarily perched in dead wood. Both species spent most (≥75%) of the time they were observed at rest, with little time spent feeding or moving. Ctenophorus isolepis spent 67% of its time in shade and was active in temperatures between 37.5°C and 43.3°C, whereas C. nuchalis spent 81% of its time in open sun and was active between 35.9°C and 48.1°C. Transect surveys at observation sites showed that open sand was the dominant habitat component available to both species. However, sand was under‐used compared with its availability. Ctenophorus isolepis instead showed strong selection for spinifex cover and C. nuchalis for dead wood; shrub cover was little used. We discuss several mechanisms that may drive the observed pattern of habitat selection, but cannot specify which is the most important. However, the results indicate clear partitioning of habitat between the two species, and suggest that this segregation may facilitate coexistence at local and regional scales.
Testing the Growth Rate vs. Geochemical Hypothesis for latitudinal variation in plant nutrients
Authors: Lovelock C. E. , Feller I. C. , Ball M. C. , Ellis J. , Sorrell B.
Published: October 2007

Two hypotheses have been proposed to explain increases in plant nitrogen (N) and phosphorus (P) concentrations with latitude: (i) geochemical limitation to P availability in the tropics and (ii) temperature driven variation in growth rate, where greater growth rates (requiring greater nutrient levels) are needed to complete growth and reproduction within shorter growing seasons in temperate than tropical climates. These two hypotheses were assessed in one forest type, intertidal mangroves, using fertilized plots at sites between latitudes 36º S and 27º N. The N and P concentrations in mangrove leaf tissue increased with latitude, but there were no trends in N : P ratios. Growth rates of trees, adjusted for average minimum temperature showed a significant increase with latitude supporting the Growth Rate Hypothesis. However, support for the Geochemical Hypothesis was also strong; both photosynthetic P use efficiency and nutrient resorption efficiency decreased with increasing latitude, indicating that P was less limiting to metabolism at the higher latitudes. Our study supports the hypothesis that historically low P availability in the tropics has been an important selective pressure shaping the evolution of plant traits.
Living with Capitalism: From Hobson to Giddens
Authors: Townshend Jules
Published: October 2007

Many commentators have noted the intellectual parallels between New Labour and New Liberalism without spelling them out in much detail. This article highlights these parallels through comparing the thoughts of J. A. Hobson, a key thinker within New Liberalism and British social democracy, and Anthony Giddens, the most prominent ‘Third Way’ thinker. Not only were there striking and surprising similarities, but their differences raise questions about how the ‘left-of-centre’ political project realises its normative commitments within a changing capitalist world.
From Beliefs to Arguments: Interpretive Methodology and Rhetorical Political Analysis
Authors: Finlayson Alan
Published: October 2007

This article examines the development of methods of political analysis concerned with ideas, beliefs and meanings and argues that these need to be supplemented by an approach attuned to the specific nature of political action. It argues that since politics involves the contest of ideas, beliefs and meanings, analysis should focus on arguments. Considering methods for the study of political arguments the article argues for a re-examination of the rhetorical tradition and the development of a Rhetorical Political Analysis (RPA). It then outlines the sorts of things this would examine, the questions it would ask and the ways in which it might go about answering them.
Poverty, Security and the Janus-Faced State
Authors: Eadie Pauline
Published: October 2007

In this article Polanyi's double move and Wæver's securitisation argument inform an analysis of poverty as a security issue. The inclusion of poverty on the security agenda confirms and complicates, rather than marginalises, the state as a central referent of security. It is argued that analytically and pragmatically qualitative and socially contextualised analysis of poverty offers deeper understanding than quantitative approaches. It is also argued that the rhetoric of inclusion currently espoused by the likes of the World Bank seeks to secure institutional hegemony rather than state or human security. Neo-liberal solutions to poverty premised on growth, as opposed to redistribution, mean that the states and peoples poorly equipped to compete in the capitalist game will remain impoverished. Markets and neo-liberal institutions serve to splinter, rather than coalesce, state and society.
Attitudes towards the Child Trust Fund: What do Parents Think?
Authors: Prabhakar Rajiv
Published: October 2007

The Labour government has recently introduced the Child Trust Fund. This pays all new babies a £250 or £500 capital endowment from government. This is locked into a special account until the child's 18th birthday. Parents are key to the success of this policy as they will make many of the key decisions about savings and investment. Little is known, however, about what new parents think of this policy. This article addresses this question by providing original evidence on what parents think of the basic features of this policy; whether the Child Trust Fund will make them more likely to save; attitudes towards the responsible use of the Child Trust Fund; and whether parents would prefer money spent on different forms of assistance rather than the Child Trust Fund.
Lies, Damned Lies and Literature: George Orwell and ‘The Truth’
Authors: Ingle Stephen
Published: October 2007

This article sets out to illustrate the value of imaginative literature as a tool of political analysis. It investigates the nature of truth and lies principally through a discussion of Orwell's Nineteen Eighty-Four. Hannah Arendt's concerns about new forms of political lying provide a platform for a detailed analysis of Orwell's depiction of the struggle between the individual and the state over the nature of reality and truth. We consider the plausibility of the Party's attempt to recreate the truth in its own image, especially through the control of language. Orwell's novel, we shall conclude, stands as a stark warning against allowing civil society to atrophy and the state to subvert ordinary language, thereby destroying the basis of representative government, trust.
Measuring the Advantages of Multivariate vs. Univariate Forecasts
Authors: Peña Daniel , Sánchez Ismael
Published: October 2007

Abstract. Suppose we are interested in forecasting a time series and, in addition to the time series data, we have data from many time series related to the one we want to forecast. Since building a dynamic multivariate model for the set of time series can be a complex task, it is important to measure in advance the increase in precision to be attained by using multivariate forecasts with respect to univariate ones. This article presents a simple procedure designed to obtain a consistent estimate of this measure. Its performance is illustrated with Monte Carlo simulations and examples.
PROCESSION AND SYMBOLISM AT TARA: ANALYSIS OF TECH MIDCHÚARTA (THE ‘BANQUETING HALL’) IN  THE CONTEXT OF THE SACRAL CAMPUS
Authors: NEWMAN CONOR
Published: October 2007

Summary.  New analysis explores Tech Midchúarta (the ‘Banqueting Hall’) from the point of view of a sacral, processional approach to the summit of the Hill of Tara, the pre‐eminent cult and inauguration site of prehistoric and early medieval Ireland. It is suggested that aspects of its architectural form symbolize the liminal boundary between the human world and the Otherworld of Tara, and that in so far as Tech Midchúarta is also designed to control and manipulate how the ceremonial complex is disclosed to the observer, it assembles the existing monuments into one, integrated ceremonial campus. It is argued that Tech Midchúarta is one of the later monuments on the Hill of Tara and that it may date from the early medieval period. Using the evidence of documentary sources and extant monuments, a possible processional route from Tech Midchúarta to Ráith na Ríg is described.

Immráidem fós Long na Láech

frisanabar Barc Ban mbáeth.

Tech na Fían, nirbo long lec,

co cethri doirsib deac.

Let us consider too the Hall of the Heroes

which is called the Palace of Vain Women;

the House of Warriors, it was no mean hall,

with fourteen doors.

(Gwynn 1903–35, Metrical Dindshenchas III, 18)
On consumer trust and product loyalty
Authors: Alhabeeb M.J.
Published: October 2007

Using a multidimensional conceptualization and drawing on previous theoretical frameworks, this study identifies the dynamic relationships between consumer trust and product loyalty, and explores the mechanism, by which these constructs are formed. It further examines the nature and direction of the chain of effects related to the formation of consumer trust and loyalty and their links, all in the context of the core relationship between consumers and firms from the production to consumption, and back to production again. This analysis implies that blind consumer loyalty to a product may lead to the elevation of producer's power and give a blank card for setting prices, adjusting quality and altering services, and ultimately reversing consumer sovereignty. The analysis also implies that consumer satisfaction domain spans much more over and beyond the consumption of a product and the consumer–firm relationship extends way beyond having the product and paying for it.
Consumer overindebtedness: a review of the quality of money advice services in Scotland
Authors: Brennan Carol , Gallagher Kelly
Published: October 2007

Levels of consumer borrowing and debt in the UK and globally continue to rise. Credit makes a vital contribution to the success of the UK economy by driving economic activity and allowing consumers flexibility in how they choose to access the marketplace and manage their finances. Although most consumers manage their borrowing effectively, for a minority, the ease of access to credit results in overindebtedness. As a consequence, the need for money advice is prevalent. In the UK in recent years, services have been developed to assist consumers in financial difficulty. In Scotland, additional funding has been made available to enable further service developments in local government or voluntary sector provision. This paper reviews the literature on consumer overindebtedness, the development of money advice services and discusses the quality of these services in Scotland. It is likely to be of interest in other countries where consumer overindebtedness is rising and where money advice services are being developed to assist those experiencing problems. The review found that the rising levels of overindebtedness justify the case for developing money advice services but that there are many quality issues which require to be managed. Implications for the money advice profession were identified together with suggestions for the development of services in other countries.
Tight junctions contain oligomeric protein assembly critical for maintaining blood–brain barrier integrity in vivo
Authors: McCaffrey Gwen , Staatz William D. , Quigley Carolyn A. , Nametz Nicole , Seelbach Melissa J. , Campos Chris R. , Brooks Tracy A. , Egleton Richard D. , Davis Thomas P.
Published: October 2007

Tight junctions (TJs) are major components of the blood–brain barrier (BBB) that physically obstruct the interendothelial space and restrict paracellular diffusion of blood‐borne substances from the peripheral circulation to the CNS. TJs are dynamic structures whose intricate arrangement of oligomeric transmembrane and accessory proteins rapidly alters in response to external stressors to produce changes in BBB permeability. In this study, we investigate the constitutive trafficking of the TJ transmembrane proteins occludin and claudin‐5 that are essential for forming the TJ seal between microvascular endothelial cells that inhibits paracellular diffusion. Using a novel, detergent‐free OptiPrep density‐gradient method to fractionate rat cerebral microvessels, we identify a plasma membrane lipid raft domain that contains oligomeric occludin and claudin‐5. Our data suggest that oligomerization of occludin involves disulfide bond formation within transmembrane regions, and that assembly of the TJ oligomeric protein complex is facilitated by an oligomeric caveolin scaffold. This is the first time that distribution of oligomeric TJ transmembrane proteins within plasma membrane lipid rafts at the BBB has been examined in vivo. The findings reported in this study are critical to understand the mechanism of assembly of the TJ multiprotein complex that is essential for maintaining BBB integrity.
Serotoninergic modulation of GABAergic synaptic transmission in developing rat CA3 pyramidal neurons
Authors: Choi In‐Sun , Cho Jin‐Hwa , Kim Jung‐Tak , Park Eun‐Joo , Lee Maan‐Gee , Shin Hong‐In , Choi Byung‐Ju , Jang Il‐Sung
Published: October 2007

Serotoninergic modulation of GABAergic mIPSCs was investigated in immature (postnatal 12–16‐days old) rat CA3 pyramidal neurons using a conventional whole‐cell patch clamp technique. Serotonin or 5‐hydroxytryptamine (5‐HT) (10 μmol/L) transiently and explosively increased mIPSC frequency with a small increase in the current amplitude. However, 5‐HT did not affect the GABA‐induced postsynaptic currents, indicating that 5‐HT acts presynaptically to facilitate the probability of spontaneous GABA release. The 5‐HT action on GABAergic mIPSC frequency was completely blocked by 100 nmol/L MDL72222, a selective 5‐HT3 receptor antagonist, and mimicked by mCPBG, a selective 5‐HT3 receptor agonist. The 5‐HT action on GABAergic mIPSC frequency was completely occluded either in the presence of 200 μmol/L Cd2+ or in the Na+‐free external solution, suggesting that the 5‐HT3 receptor‐mediated facilitation of mIPSC frequency requires a Ca2+influx passing through voltage‐dependent Ca2+channels from the extracellular space, and that presynaptic 5‐HT3 receptors are less permeable to Ca2+. The 5‐HT action on mIPSC frequency in the absence or presence of extracellular Na+ gradually increased with postnatal development. Such a developmental change in the 5‐HT3 receptor‐mediated facilitation of GABAergic transmission would play important roles in the regulation of excitability as well as development in CA3 pyramidal neurons.
Critical role of ABCA1 transporter in sphingosine 1‐phosphate release from astrocytes
Authors: Sato Koichi , Malchinkhuu Enkhzol , Horiuchi Yuta , Mogi Chihiro , Tomura Hideaki , Tosaka Masahiko , Yoshimoto Yuhei , Kuwabara Atsushi , Okajima Fumikazu
Published: October 2007

Sphingosine 1‐phosphate (S1P) is accumulated in lipoproteins, especially high‐density lipoprotein (HDL), in plasma. However, it remains uncharacterized how extracellular S1P is produced in the CNS. The treatment of rat astrocytes with retinoic acid and dibutyryl cAMP, which induce apolipoprotein E (apoE) synthesis and HDL‐like lipoprotein formation, stimulated extracellular S1P accumulation in the presence of its precursor sphingosine. The released S1P was present together with apoE particles in the HDL fraction. S1P release from astrocytes was inhibited by the treatment of the cells with glybenclamide or small interfering RNAs specific to ATP‐binding cassette transporter A1 (ABCA1). Astrocytes from Abca1−/− mice also showed impairment of retinoic acid/dibutyryl cAMP‐induced S1P release in association with the blockage of HDL‐like lipoprotein formation. However, the formation of either apoE or lipoprotein itself was not sufficient, and additional up‐regulation of ABCA1 was requisite to stimulate S1P release. We conclude that the S1P release from astrocytes is coupled with lipoprotein formation through ABCA1.
Signal transduction in Alzheimer disease: p21‐activated kinase signaling requires C‐terminal cleavage of APP at Asp664
Authors: Nguyen Thuy‐Vi V. , Galvan Veronica , Huang Wei , Banwait Surita , Tang Huidong , Zhang Junli , Bredesen Dale E.
Published: October 2007

The deficits in Alzheimer disease (AD) stem at least partly from neurotoxic β‐amyloid peptides generated from the amyloid precursor protein (APP). APP may also be cleaved intracellularly at Asp664 to yield a second neurotoxic peptide, C31. Previously, we showed that cleavage of APP at the C‐terminus is required for the impairments seen in APP transgenic mice, by comparing elements of the disease in animals modeling AD, with (platelet‐derived growth factor B‐chain promoter‐driven APP transgenic mice; PDAPP) versus without (PDAPP D664A) a functional Asp664 caspase cleavage site. However, the signaling mechanism(s) by which Asp664 contributes to these deficits remains to be elucidated. In this study, we identify a kinase protein, recently shown to bind APP at the C‐terminus and to contribute to AD, whose activity is modified in PDAPP mice, but normalized in PDAPP D664A mice. Specifically, we observed a significant increase in nuclear p21‐activated kinase (isoforms 1, 2, and or 3; PAK‐1/2/3) activation in hippocampus of 3 month old PDAPP mice compared with non‐transgenic littermates, an effect completely prevented in PDAPP D664A mice. In contrast, 13 month old PDAPP mice displayed a significant decrease in PAK‐1/2/3 activity, which was once again absent in PDAPP D664A mice. Similarly, in hippocampus of early and severe AD subjects, there was a progressive and subcellular‐specific reduction in active PAK‐1/2/3 compared with normal controls. Interestingly, total PAK‐1/2/3 protein was increased in early AD subjects, but declined in moderate AD and declined further, to significantly below that of control levels, in severe AD. These findings are compatible with previous suggestions that PAK may be involved in the pathophysiology of AD, and demonstrate that both early activation and late inactivation in the murine AD model require the cleavage of APP at Asp664.
Binding of zinc(II) and copper(II) to the full‐length Alzheimer’s amyloid‐β peptide
Authors: Tõugu Vello , Karafin Ann , Palumaa Peep
Published: October 2007

There is evidence that binding of metal ions like Zn2+ and Cu2+ to amyloid beta‐peptides (Αβ) may contribute to the pathogenesis of Alzheimer’s disease. Cu2+ and Zn2+ form complexes with Αβ peptides in vitro; however, the published metal‐binding affinities of Αβ vary in an enormously large range. We studied the interactions of Cu2+ and Zn2+ with monomeric Αβ40 under different conditions using intrinsic Αβ fluorescence and metal‐selective fluorescent dyes. We showed that Cu2+ forms a stable and soluble 1 : 1 complex with Αβ40, however, buffer compounds act as competitive copper‐binding ligands and affect the apparent KD. Buffer‐independent conditional KD for Cu(II)‐Αβ40 complex at pH 7.4 is equal to 0.035 μmol/L. Interaction of Αβ40 with Zn2+ is more complicated as partial aggregation of the peptide occurs during zinc titration experiment and in the same time period (within 30 min) the initial Zn‐Αβ40 complex (KD = 60 μmol/L) undergoes a transition to a more tight complex with KD ∼ 2 μmol/L Competition of Αβ40 with ion‐selective fluorescent dyes Phen Green and Zincon showed that the KD values determined from intrinsic fluorescence of Αβ correspond to the binding of the first Cu2+ and Zn2+ ions to the peptide with the highest affinity. Interaction of both Zn2+ and Cu2+ ions with Αβ peptides may occur in brain areas affected by Alzheimer’s disease and Zn2+‐induced transition in the peptide structure might contribute to amyloid plaque formation.
COMPUTER PROGRAMS: onesamp: a program to estimate effective population size using approximate Bayesian computation
Authors: TALLMON DAVID A. , KOYUK ALLY , LUIKART GORDON , BEAUMONT MARK A.
Published: October 2007

The estimation of effective population size from one sample of genotypes has been problematic because most estimators have been proven imprecise or biased. We developed a web‐based program, onesamp that uses approximate Bayesian computation to estimate effective population size from a sample of microsatellite genotypes. onesamp requires an input file of sampled individuals’ microsatellite genotypes along with information about several sampling and biological parameters. onesamp provides an estimate of effective population size, along with 95% credible limits. We illustrate the use of onesamp with an example data set from a re‐introduced population of ibex Capra ibex.
Gut content identification of larvae of the Anopheles gambiae complex in western Kenya using a barcoding approach
Authors: GARROS C. , NGUGI N. , GITHEKO A. E. , TUNO N. , YAN G.
Published: October 2007

Although larvae feeding and food source are vital to the development, survival and population regulation of African malaria vectors, the prey organisms of Anopheles gambiae larvae in the natural environment have not been well studied. This study used a molecular barcoding approach to investigate the natural diets of Anopheles gambiae s.l. larvae in western Kenya. Gut contents from third‐ and fourth‐instar larvae from natural habitats were dissected and DNA was extracted. The 18S ribosomal DNA gene was amplified, the resulting clones were screened using a restriction fragment length polymorphism method and nonmosquito clones were sequenced. Homology search and phylogenetic analyses were then conducted using the sequences of non‐mosquito clones to identify the putative microorganisms ingested. The phylogenetic analyses clustered ingested microorganisms in four clades, including two clades of green algae (Chlorophyta, Chlorophyceae Class, Chlamydomonadales and Chlorococcales families), one fungal clade, and one unknown eukaryote clade. In parallel, using the same approach, an analysis of the biodiversity present in the larval habitats was carried out. This present study demonstrated the feasibility of the barcoding approach to infer the natural diets of Anopheles gambiae larvae. Our analysis suggests that despite the wide range of microorganisms available in natural habitats, mosquito larvae fed on specific groups of algae. The novel tools developed from this study can be used to improve our understanding of the larval ecology of African malaria vectors and to facilitate the development of new mosquito control tools.
A robotic molecular method for in situ detection of marine invertebrate larvae
Authors: JONES WILLIAM J. , PRESTON CHRISTINA M. , MARIN III ROMAN , SCHOLIN CHRISTOPHER A. , VRIJENHOEK ROBERT C.
Published: October 2007

Knowledge of the temporal and spatial abundance of invertebrate larvae is critical to understanding the dispersal capabilities and recruitment potential of marine and aquatic organisms. Traditional microscopic analyses are time‐consuming and difficult given the diversity of larval species and a frequent lack of discriminating morphological characteristics. Here, we describe a sensitive rRNA targeted sandwich hybridization assay (SHA) that uses oligonucleotide probes to detect and enumerate the larvae of invasive green crabs (Carcinus maenas), native blue mussels (Mytilus), native barnacles (Balanus) and polychaetes (Osedax and Ophelia) that occur in the Monterey Bay National Marine Sanctuary, California. Laboratory‐based assays demonstrate specificity, high sensitivity, and a quantitative response to cultured samples from three of the target organisms. Oligonucleotide probes were then printed in arrays on nitrocellulose membranes and deployed in our robotic Environmental Sample Processor (ESP) to detect larvae in situ and autonomously. We demonstrate that the SHA‐detection method and ESP robot can be used for near real‐time, in situ detection of larval species in the marine environment.
New evidence on the systematic and phylogenetic position of Parides burchellanus (Lepidoptera: Papilionidae)
Authors: SILVA‐BRANDÃO K. L. , AZEREDO‐ESPIN A. M. L. , FREITAS A. V. L.
Published: October 2007

Parides burchellanus is considered a rare and threatened swallowtail species restricted to central Brazil. It shows considerable morphological similarity to Parides panthonus jaguarae, with which it shares both geographical range and larval host plant. At present, P. burchellanus and P. panthonus are believed to be distinct species, based on minor differences in male genitalia. In this study, the phylogenetic and systematic position of P. burchellanus in relation to three subspecies of P. panthonus (P. p. jaguarae, P. p. lysimachus and P. p. aglaope) was evaluated using molecular evidence: the complete sequence of the mtDNA genes COI and COII and of the nuclear gene EF‐1α (c. 3300 bp). In addition, the informativeness of the ‘barcode’ region next to the 5′ end of COI (c. 650 bp) was evaluated for delimiting these taxa. Individual analysis by neighbour‐joining, using Kimura 2‐parameter distance model, and by maximum parsimony showed that P. p. jaguarae + P. p. lysimachus + P. p. aglaope + P. burchellanus form a strongly supported monophyletic clade, and all molecular regions consistently recovered P. p. jaguarae and P. burchellanus as sister species. The genetic divergence among the subspecies of P. panthonus and P. burchellanus is equivalent to the divergence among conspecifics of other species of Parides, and smaller than the interspecific divergence among different sister species of this genus. The results support the proposal that P. p. jaguarae and P. burchellanus are likely to be synonymous, and suggest that P. burchellanus can be considered conspecific with P. panthonus. The taxonomic classification of P. burchellanus should be revised on the basis of the molecular data.
Microsatellite DNA markers for the snow vole (Chionomys nivalis)
Authors: WANDELER P. , RAVAIOLI S. R. , BUCHER T. B.
Published: October 2007

A total of 14 dinucleotide microsatellite loci were characterized in the snow vole (Chionomys nivalis). Allelic polymorphism across all loci and 28 individuals representing a single population in the Swiss Alps was high (mean = 10.1 alleles). No significant linkage disequilibrium between pairs of loci and no departure from Hardy–Weinberg equilibrium were found. These loci will be useful for describing mating systems and population structure and to investigate the genetic consequences of a species living in a highly fragmented habitat.
Biosignatures present in a hydrothermal massive sulfide from the Mid‐Atlantic Ridge
Authors: BLUMENBERG M. , SEIFERT R. , PETERSEN S. , MICHAELIS W.
Published: October 2007

Mid‐ocean spreading and accompanying hydrothermal activities result in huge areas with exposure of minerals rich in reduced chemicals – basaltic and peridotitic rocks as well as metal sulfide precipitates – to the oxygenated seawater. Oxidation of Fe and S present in these rocks provides an extensive long‐term source of energy to lithotrophs.

Investigation of lipid biomarkers and their carbon isotope ratios from a massive iron sulfide of an inactive sulfide mound or inactive chimney sampled at the western flank of the Turtle‐Pits hydrothermal field (Mid‐Atlantic Ridge, 5°S) revealed a unique lipid distribution. The bacterial fauna appears to be dominated by chemolithotrophs with a distinct lipid composition mainly comprising of iso‐branched fatty acids and nonisoprenoidal dialkyl glycerol diethers partially including the very rare macrocyclic cores with 30–35 carbon atoms (including 13,16‐dimethyloctacosane and 5,13,16‐trimethyloctacosane). The Bacteria are accompanied by most likely hydrogen/CO2‐dependent methanogenic Archaea (e.g. Methanococcus) as well as other Archaea with a different life style (e.g. Ferroplasma). Alike some of the bacterial lipids the archaeal lipids predominantly consist of macrocyclic diethers including one C40 and one C41 isoprenoid. Structural homologues of the latter are so far only reported from a methanogenic archaeum and a Pleistocene sulfur deposit. Compound‐specific analyses of the stable isotope ratios revealed δ13C values for the majority of bacterial and archaeal lipid components of about 0‰ (vs. VPDB), indicative for chemolithoautotrophically fixed carbon which is, for distinct pathways, accompanied by only negligible fractionations. However, the presence of methanogenic Archaea is indicated by 13C‐depleted isoprenoidal lipids (δ13C ~ –50‰) characteristic for certain CO2‐reducing methanogens synthesizing lipids via acetyl CoA.
Mitochondrial function and apoptotic susceptibility in aging skeletal muscle
Authors: Chabi Béatrice , Ljubicic Vladimir , Menzies Keir J. , Huang Julianna H. , Saleem Ayesha , Hood David A.
Published: October 2007

During aging, skeletal muscle undergoes sarcopenia, a condition characterized by a loss of muscle cell mass and alterations in contractile function. The origin of these decrements is unknown, but evidence suggests that they can be partly attributed to mitochondrial dysfunction. To characterize the nature of this dysfunction, we investigated skeletal muscle contractile properties, subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondrial biogenesis and function, as well as apoptotic susceptibility in young (6 months old) and senescent (36 months old) Fischer 344 Brown Norway rats. Muscle mass and maximal force production were significantly lower in the 36‐month group, which is indicative of a sarcopenic phenotype. Furthermore, contractile activity in situ revealed greater fatigability in the 36‐month compared to the 6‐month animals. This decrement could be partially accounted for by a 30% lower mitochondrial content in fast‐twitch muscle from 36‐month animals, as well as lower protein levels of the transcriptional coactivator peroxisome proliferator‐activated receptor γ coactivator‐1α. Enzyme activities and glutamate‐induced oxygen consumption rates in isolated SS and IMF mitochondria were similar between age groups. However, mitochondrial reactive oxygen species (ROS) production during state 3 respiration was ~1.7‐fold greater in mitochondria isolated from 36‐month compared to 6‐month animals, and was accompanied by a 1.8‐fold increase in the DNA repair enzyme 8‐oxoguanine glycosylase 1 in fast‐twitch muscle. Basal rates of release of cytochrome c and endonuclease G in SS mitochondria were 3.5‐ to 7‐fold higher from senescent animals. These data suggest that the age‐related sarcopenia and muscle fatigability are associated with enhanced ROS production, increased mitochondrial apoptotic susceptibility and reduced transcriptional drive for mitochondrial biogenesis.
Remarkable longevity and stress resistance of nematode PI3K‐null mutants
Authors: Ayyadevara Srinivas , Alla Ramani , Thaden John J. , Shmookler Reis Robert J.
Published: October 2007

The great majority of lifespan‐augmenting mutations were discovered in the nematode Caenorhabditis elegans. In particular, genetic disruption of insulin‐like signaling extends longevity 1.5‐ to 3‐fold in the nematode, and to lesser degrees in other taxa, including fruit flies and mice. C. elegans strains bearing homozygous nonsense mutations in the age‐1 gene, which encodes the class‐I phosphatidylinositol 3‐kinase catalytic subunit (PI3KCS), produce progeny that were thought to undergo obligatory developmental arrest. We now find that, after prolonged developmental times at 15–20 °C, they mature into extremely long‐lived adults with near‐normal feeding rates and motility. They survive to a median of 145–190 days at 20 °C, with nearly 10‐fold extension of both median and maximum adult lifespan relative to N2DRM, a long‐lived wild‐type stock into which the null mutant was outcrossed. PI3K‐null adults, although a little less thermotolerant, are considerably more resistant to oxidative and electrophilic stresses than worms bearing normal or less long‐lived alleles. Their unprecedented factorial gains in survival, under both normal and toxic environments, are attributed to elimination of residual and maternally contributed PI3KCS or its products, and consequent modification of kinase signaling cascades.
PROBLEMS OF THE RADIOCARBON CALENDAR AND ITS CALIBRATION
Authors: RENFREW C. , CLARK R. M.
Published: October 2007

ABSTRACTS

Both the growing body of literature on the tree‐ring calibration of radiocarbon dates, and the variety of statistical approaches used, make it appropriate to review the basic principles involved in the construction of a calibration curve. While its ultimate validity is in part a geophysical problem, the appropriate form for the calibration function, given a specific body of data, is a statistical question centering upon the analysis of the measurement errors involved. The relationship between the calibration function and the inverse calibration function is examined, and the shortcomings of the available published calibration curves considered in the light of this examination. It is concluded that there is no reason to doubt the general principles on which the calibration is based, but a need exists for a more critical handling of the measurement data with a statistical treatment of the errors involved. The quality of the data could itself be improved by the use of replicate samples for inter‐laboratory projects specifically designed to investigate the magnitude of measurement error.
DENDROCHRONOLOGY—A REFERENCE CURVE FOR SLOW GROWN OAKS, A.D. 1230 TO 1546
Authors: FLETCHER J. M. , TAPPER M. C. , WALKER F. S.
Published: October 2007

ABSTRACTS

Details are given of how the widths of the annual rings of oak boards, which form the panels for certain sixteenth‐century portraits painted in south‐east England or adjacent parts of the Continent, have been matched with one another. A representative ring‐width curve based on eighteen trees has been obtained and dated by region‐to‐region bridging from the master chronology, derived at Munich, for oaks grown in central and southern Germany. The feasibility of dendrochronology for oaks of slow and regular growth in late medieval times has been established for a region which extends beyond south‐east England to Oxford on the west and to Flanders and parts of France on the east and south‐east.
THERMOLUMINESCENT AUTHENTICITY STUDIES OF UNGLAZED T‘ANG DYNASTY CERAMIC TOMB GOODS
Authors: FLEMING S. J.
Published: October 2007

ABSTRACTS

Imitations of T‘ang Dynasty (a.d. 618–906) ceramics were produced at the beginning of this century casting them from original piece‐moulds. The impeccable style of these wares means they are indistinguishable from their ancient prototypes by visual inspection. Examples of such imitative material are revealed by thermoluminescent dating analysis. A brief discussion of the need for and methods of the piece‐moulding technique in its use by the T‘ang artisan is also given.
RECENTLY IDENTIFIED EGYPTIAN PIGMENTS
Authors: RIEDERER J.
Published: October 2007

ABSTRACTS

On several bowls from Nubia (1600 b.c.) and on one canopic jar (New Kingdom) huntite, a calciummagnesium‐carbonate CaCO3. 3MgCO3 was identified by means of X‐ray diffraction and infra‐red absorption techniques. Vases from the Amarna period (1370 b.c.) are decorated with a blue paint, which proved to be cobalt‐blue. Copper chloride atacamite was used on limestone reliefs from Thebes‐West but the green frit chrysocolla occurs more frequently on Egyptian objects as is mentioned in literature.
An inexpensive stereo‐image capture tool for motion study
Authors: Chong Albert K.
Published: October 2007

This paper discusses the evaluation of a video stereo‐image capture tool for photogrammetric applications. The ‘‘NuView Adapter’’, a commonly available video‐image splitting device, and a digital video camera (DV) could be used to capture stereoscopic video footage for many photogrammetric applications in which low‐cost near‐simultaneous stereo‐images are required for 3D viewing or for 3D spatial data capture. Relevant photogrammetric applications might include: aerial surveillance, human/animal motion study (tracking), bank/security surveillance and precise 3D animation. The device permits two distinct views (left and right perspective views) to enter a single lens DV. A single convergence control in the device allows the user to obtain a stereo view of near and far objects. The system is easy to operate and the stereo‐images give a good visual 3D effect. Research was carried out to determine the quality of the stereo‐image for 3D measurement. The investigation involved: (1) the calibration of a customised system for optimum close range photogrammetric application; and (2) a case study involving motion tracking. A semi‐automated monodigitising photogrammetric technique was used to determine the accuracy of the system. The results show that this system could achieve a spatial data accuracy of better than 13 mm at an object distance of 9 m. The horizontal and vertical accuracies are similar to those obtained by the conventional stereoscopic camera technique using a ‘‘normal case’’ configuration with 86% overlap.