bluuebunny/crossref_metadata_2025 huggingface dataset:
The Accuracy of Memory for Faces of Personally Known Individuals
Authors: Brédart Serge , Devue Christel
Published: January 2006

The present study was aimed at evaluating whether the very high accuracy of memory for familiar faces, demonstrated by Ge et al (2003, Perception32 601–614) with a very familiar famous person, generalises to faces of personally known individuals. The accuracy of participants' perceptual memory for a close colleague's face and for their own face was evaluated by presenting original and manipulated pictures of these two targets. The manipulation consisted of increasing or decreasing the interocular distance. As in Ge et al's study, results indicated that proportions of correct recognition of the original faces, and just noticeable differences for the detection of alterations in the recognition task, were not significantly different from the corresponding measures in a perceptual discrimination task performed by a sample of participants who did not know the target persons at all. High accuracy of memory generalises to faces of personally known individuals.
Phylogenetic relationships within Nereididae (Annelida : Phyllodocida)
Authors: Santos Cinthya S. G. , Pleijel Fredrik , Lana Paulo , Rouse Greg W.
Published: January 2006

Nereididae Johnston, 1865, part of the large clade Phyllodocida, is one of the best-known annelid groups. Presently, there are some 500 nominal species grouped into 42 genera, although there is little consensus among different authors as to how they should be classified. The relationships of nereidids were assessed in a morphology-based parsimony analysis of 41 terminal taxa, with members of Chrysopetalidae and Hesionidae used as outgroups. Type species for the majority of currently recognised nereidid genera were used as terminal taxa, and character information was based on examination of type and non-type specimens, together with literature descriptions. High degrees of homoplasy were found for several features that are traditionally applied to delineate subgroups of Nereididae, including the presence of paragnaths and the distribution of different kinds of chaetae. Six major groups were recovered: Namanereidinae, including Namalycastis and Namanereis, characterised by spherical shape of palpostyles and ventrally displaced notoaciculae; one clade corresponding in part to previous authors concepts of Nereidinae, including Nereis, Eunereis, Hediste and Platynereis (the relationships of several well known nereidids, such as Neanthes and Perinereis, commonly referred to Nereidinae, could not be unambiguously resolved); one unnamed and not previously recognised clade (A), including Australonereis, Laeonereis, Dendronereides and Olganereis, characterised by the presence of papillae on the maxillary ring; a second unnamed clade (B), including Leptonereis, Sinonereis, Tylonereis and Tylorrhynchus, characterised by enlarged notopodial ligulae; a well supported Gymnonereidinae, restricted to Ceratocephale, Gymnonereis, Tambalagamia and Micronereides; and a third unnamed clade (C), including Ceratonereis, Solomononereis, Unanereis, Cheilonereis and Websterinereis, characterised by unilobated neuropodial postchaetal lobes. Among these groups we found good support for the Namanereidinae, the Gymnonereidinae and for the whole of Nereididae. The subfamilies Dendronereidinae and Notophycinae (based on Micronereis, senior synonym of Notophycus) are regarded here as monotypic.
Evolutionary trends in derelomine flower weevils (Coleoptera : Curculionidae): from associations to homology
Authors: Franz Nico M. , Valente Roberta M.
Published: January 2006

The host-plant associations and life histories of weevils in the pantropical tribe Derelomini are reviewed in light of new phylogenetic insights. The most immediate derelomine ancestor likely had a ‘special association’ with the inflorescences of palms (Arecaceae) involving pollination and oviposition into dispensable male flowers. Case studies of select genus groups show multiple historical forces driving their diversification. In the South and Central American genus Celetes, abundant host shifts are important, though clearly not enough to account for the existence of all species. Females of the Neotropical genus Staminodeus have remarkable morphogical and behavioural modifications for exploiting the staminodes of cyclanth (Cyclanthaceae) inflorescences. The evolution of males in this genus is mostly explained by sexual selection. Cyclanthura illustrates the potential of the weevils for colonising hosts with widely divergent inflorescence biologies, including arums (Araceae) in the genus Anthurium. Members of the Ganglionus–Systenotelus clade, in turn, are exclusively associated with the cyclanth genus Carludovica. A phylogenetic trend in this group to attack the plants’ seeds has led to a series of counteracting transformations in inflorescence morphology. Overall there were at least three independent secondary host shifts to dicots, including one in the taxonomically complex genus Phyllotrox. The results suggest that in this particular tribe of weevils, focusing on the homology of specific biological traits in individual lineages is more likely to produce new knowledge than a formalistic, large-scale approach.
Revision and cladistic analysis of the spider genus Carapoia González-Sponga (Araneae : Pholcidae), with descriptions of new species from Brazil's Atlantic forest
Authors: Huber Bernhard A.
Published: January 2006

The pholcid genus Carapoia is revised and interspecific relationships are analysed cladistically. Five new species from the Brazilian Atlantic forest are described (C. ubatuba, C. brescoviti, C. una, C. crasto, C. rheimsae), and new records are given for the four previously described species. Cladistic analysis reveals a biogeographic split between a northern clade (Amazon, Venezuela, Guyana) and a southern clade (Brazilian Atlantic forest). While each of the three northern species is widely distributed, the six Atlantic forest species seem to be restricted to much smaller areas of forest remnants along the Atlantic coast.
Assessing the trophic link between seagrass habitats and piscivorous fishes
Authors: Hindell Jeremy S.
Published: January 2006

Links between piscivorous fishes and seagrass habitat were investigated in Port Phillip Bay, Australia. Abundances of piscivorous fish were estimated, the contribution of fish to their diets was measured and the trophic link between these fish and seagrass beds was assessed with stable isotopes. Piscivorous fishes were common in seagrass and included eight species from seven families (33% by abundance). They consumed at least eight families of teleost prey, including juveniles of seagrass-associated taxa, such as monacanthids (e.g. Meuschenia freycineti) and syngnathids (Stigmatopora argus). No fish were exclusively piscivorous and contribution of fish to the diets of the most common species (Arripis truttacea and Kestratherina esox) varied strongly through time. Putative contributions of each source (primary producer – plant) to the nutrition of piscivorous fishes were: (1) fishes whose base for nutritional support was driven mostly (>50%) by seagrass (e.g. Platycephalus speculator and Platycephalus laevigatus); and (2) fishes whose base for nutritional support was not driven by any particular primary producer (e.g. Arripis truttacea and Pseudocaranx dentex). The propensity for piscivorous fish to include seagrass-associated fish in their diets, their perennial presence in seagrass and the strong putative contribution by seagrass to their nutrition, suggest that seagrass habitats can be valuable habitat for piscivorous fishes.
Growth of the encrusting sponge Tedania anhelans (Lieberkuhn) on vertical and on horizontal surfaces of temperate subtidal reefs
Authors: Knott N. A. , Underwood A. J. , Chapman M. G. , Glasby T. M.
Published: January 2006

On subtidal reefs around Sydney (Australia), Tedania anhelans (Lieberkuhn, 1859)is a common encrusting sponge that occurs as frequently on vertical as on horizontal surfaces on most reefs, but covers more than twice the area on vertical surfaces of reefs. Faster growth, leading to the greater cover of the sponge on vertical surfaces, is a possible explanation for this difference. This was examined by experimental transplants to test the hypothesis that T. anhelans transplanted from vertical to horizontal surfaces grow more slowly than those on vertical surfaces. Over three months, T. anhelans transplanted to horizontal surfaces shrank, by 18 ± 18% and 17 ± 16% (mean ± s.e.) at two sites. Conversely, sponges on vertical surfaces grew rapidly, increasing by 40 ± 18% and 78 ± 19% at two sites. Potential artefacts owing to the experimental procedure of moving sponges between places were tested, but none was detected. These results indicated that orientation had a strong effect on the growth of T. anhelans and that growth has an important role in creating the pattern of its greater cover on vertical than on horizontal surfaces of temperate subtidal reefs.
Zooplankton diversity and assemblages in arid zone rivers of the Lake Eyre Basin, Australia
Authors: Shiel Russell J. , Costelloe Justin F. , Reid Julian R. W. , Hudson Peter , Powling Joan
Published: January 2006

The responses of zooplankton assemblages in arid zone rivers to seasonal changes, flow events, drying and water quality changes are fundamental to our understanding of these unregulated rivers. For three years the zooplankton and littoral microfauna in three rivers in the Lake Eyre Basin were studied. A diverse assemblage was discovered with a total of 398 identifiable taxa being recorded, consisting of 72 protist, 227 rotifer and 93 microcrustacean taxa. Zooplankton diversity was highest in a boom phase during, or in the summer following, a large flood. The rotifer assemblage dominated during, or soon after, periods of flow. However, during the winter and early summer, there was a decline in rotifer taxon richness and abundance accompanied by an increase in microcrustacean taxon richness and abundance. The winter samples occurred during the recession of a large flood and the early summer samples during periods of no flow. These changes suggested the involvement of a strong annual cycle of ecosystem structure evident within the longer term patterns of boom and bust driven by the timing and size of flood events. Multivariate and regression analyses found that salinity was a significant and independent driver of assemblage composition.
Muscle GLUT4 regulation by estrogen receptors ERβ and ERα
Authors: Barros Rodrigo P. A. , Machado Ubiratan F. , Warner Margaret , Gustafsson Jan-Åke
Published: January 2006

Estrogen is known to influence glucose homeostasis with dominant effects in the liver, but the role of estrogen receptors in muscle glucose metabolism is unknown. In the present study, we investigated the expression of the two estrogen receptors, ERα and ERβ, and their influence on regulation of the glucose transporter, GLUT4, and its associated structural protein, caveolin-1, in mouse gastrocnemius muscle. Immunohistochemical analysis revealed that ERα and ERβ are coexpressed in the nuclei of most muscle cells, and that their levels were not affected by absence of estradiol [in aromatase-knockout (ArKO) mice]. GLUT4 expression on the muscle cell membrane was not affected by loss of ERβ but was extremely reduced in ERα
-/-
mice and elevated in ArKO mice. RT-PCR confirmed a parallel reduction in GLUT4 mRNA levels in ERα
-/-
mice. Upon treatment of ArKO mice with the ERβ agonist 2,3-bis(4-hydroxyphenyl)propionitrile, GLUT4 expression was reduced. By immunofluorescence and Western blotting, caveolin-1 expression was higher in ArKO mice and lower in ERβ
-/-
and ERα
-/-
mice than in WT littermates. GLUT4 and caveolin-1 were colocalized in WT and ArKO mice but not in ERβ
-/-
and ERα
-/-
mice. These results reveal that ERα is a positive regulator of GLUT4 expression, whereas ERβ has a suppressive role. Both ERβ and ERα are necessary for optimal caveolin-1 expression. Taken together, these results indicate that colocalization of caveolin-1 and GLUT4 is not an absolute requirement for muscle glucose metabolism but that reduction in GLUT4 could be contributing to the insulin resistance observed in ERα
-/-
mice.
A multifunctional cytoprotective agent that reduces neurodegeneration after ischemia
Authors: Jiang Zhi-Gang , Lu X.-C. May , Nelson Valery , Yang Xiaofang , Pan Weiying , Chen Ren-wu , Lebowitz Michael S. , Almassian Bijan , Tortella Frank C. , Brady Roscoe O. , Ghanbari Hossein A.
Published: January 2006

Cellular and molecular pathways underlying ischemic neurotoxicity are multifaceted and complex. Although many potentially neuroprotective agents have been investigated, the simplicity of their protective mechanisms has often resulted in insufficient clinical utility. We describe a previously uncharacterized class of potent neuroprotective compounds, represented by PAN-811, that effectively block both ischemic and hypoxic neurotoxicity. PAN-811 disrupts neurotoxic pathways by at least two modes of action. It causes a reduction of intracellular-free calcium as well as free radical scavenging resulting in a significant decrease in necrotic and apoptotic cell death. In a rat model of ischemic stroke, administration of PAN-811 i.c.v. 1 h after middle cerebral artery occlusion resulted in a 59% reduction in the volume of infarction. Human trials of PAN-811 for an unrelated indication have established a favorable safety and pharmacodynamic profile within the dose range required for neuroprotection warranting its clinical trial as a neuroprotective drug.
On the indices of plant–plant competition and their pitfalls
Authors: Oksanen Lauri , Sammul Marek , Mägi Merike
Published: January 2006

The index of relative competition intensity (RCI) has serious built‐in biases, due to its asymptotic behavior when competition intensity is high and its tendency to obtain very low values when plants with neighbors intact perform better than neighbor removal plants. These biases have been partially corrected in the index of relative neighbor effect (RNE), but the existence of fixed upper and lower bounds (−1≤RNE≤+1) still creates problems and biases in communities where the average intensity of competition or facilitation is high and plant performance pronouncedly varies in space. The third commonly used index, the logarithm of response ratio (lnRR), is mathematically and statistically sound, but when computed from pair‐wise comparisons between neighbor removal and control plants, this index reflects the geometric mean of the treatment effect. Moreover, linear patterns in lnRR reflect exponential patterns in the intensity of competition. As the interest of ecologists usually focuses on arithmetic means, we propose a corrected index of relative competition intensity, CRCI=arc sin (RNE). This index is fairly linear within the observed ranges of competition and facilitation, and for the range of competition intensities where RNE behaves reasonably, the two indices obtain almost identical values.

We compared the performance of the four indices, using both imagined and real data, the latter from systems where the responses of plants to neighbor removal ranged from weak to moderate, so that RNE and CRCI were expected to behave similarly. The indices were computed both from pooled data for each community and as averages of pair‐wise comparisons. lnRR and CRCI were found to behave in a consistent and bias‐free manner, yielding similar results regardless of method of computation. This was, by and large, the case with RNE, too, but as the values of indices grew, the values from pair‐wise comparisons became increasingly smaller than values computed from pooled data. RCI yielded grossly aberrant results in computations based on pair‐wise comparisons. Therefore, the further use of RCI is unadvisable and studies where RCI has been derived from pair‐wise comparisons should be excluded from meta‐analyses.
Towards maturation of the population concept
Authors: Schaefer J. A.
Published: January 2006

Recent literature has emphasized the central role of populations in biological thought and practice, yet a unified population concept remains elusive. I contend that a more mature framework for populations could be realized by dispensing with arbitrary population bounds which, in turn, will entail recognition that populations exist on multiple spatial scales and that populations are inherently vague. I illustrate this framework by decomposing the population structure of a hypothetical organism distribution using fuzzy classification at multiple scales. Hierarchy and vagueness represent the building blocks of a more inclusive population concept.
Context‐dependent changes in the resistance and resilience of soil microbes to an experimental disturbance for three primary plant chronosequences
Authors: Orwin Kate H. , Wardle David A. , Greenfield Laurence G.
Published: January 2006

The extrinsic factors that regulate soil microbial stability (resistance and resilience) are little understood, even though soil microbes are important drivers of ecosystem function and their stability is likely to affect soil carbon storage and plant nutrient availability. Soils were collected across three primary plant chronosequences (two in New Zealand and one in Hawaii) that differed in climate, parent material and time spans to test the following hypotheses: i) there is a tradeoff between the resistance and resilience of key soil microbial response variables, ii) this tradeoff is related to the relationship of soil microbial resistance and resilience to soil resources, iii) resources change predictably during different primary plant chronosequences, and iv) if the first three hypotheses hold and are consistent for all three chronosequences, then soil microbial resistance and resilience should change predictably across different chronosequences. Results showed that although there was a tradeoff between resistance and resilience, the role of resources in determining this was unclear. Within each chronosequence, resources that were positively related to resistance were negatively related to resilience and vice versa, consistent with our second hypothesis. However, the direction and strength of correlations between stability and soil resources depended strongly on which soil microbial response variable was measured, and the chronosequence it was measured in. Total amounts of resources often showed consistent trends with ecosystem development for each chronosequence, but the way that resource quality changed varied between chronosequences. At least partly because of the variable nature of these relationships, the trajectory of resistance and resilience during ecosystem development varied considerably across chronosequences. Thus, although consistent trends were found within each chronosequence, the relationships between the stability of different soil microbial response variables, resources and ecosystem development depended strongly on which chronosequence was considered.
Are polyphagous geometrid moths with flightless females adapted to budburst phenology of local host species?
Authors: Tikkanen Olli‐Pekka , Woodcock Ben , Watt Allan , Lock Kerry
Published: January 2006

The majority of studies demonstrating local adaptation of insect herbivores involve sessile species, particularly those with a parthenogentic phase to their life history or endophagous “parasites” of plants. Current arguments suggest the strength of selection determines whether local adaptation can or cannot take place. Therefore local adaptation should not be limited to species with such traits. We studied the ability of three polyphagous geometrid moths with flightless adult females (Erannisdefoliaria, Operophtera brumata and O. fagata) to synchronise their egg hatching with the budburst of a local host species in north east Scotland. A strong selection for hatching time is expected among generalist moths given the large variation in budburst phenology and an inability to hatch in synchrony with budburst decreases moth fitness substantially. In two successive seasons, we trapped emerging females from patches of five host species and recorded the temperature sum needed for 50% egg hatch of each brood laid by the trapped females. The hatching times of broods were compared against the average budburst time of the maternal host species in the study area. In addition, the trapping dates of each female were recorded. Only O. brumata showed synchrony with egg hatch and budburst which suggests local phenological adaptation to different host species. This could be maintained by selection and partial reproductive isolation between populations dwelling on different host species. No phenological adaptation was found in the other common geometrids of the study area.
A bounded null model explains juvenile tree community structure along light availability gradients in a temperate rain forest
Authors: Lusk Christopher H. , Chazdon Robin L. , Hofmann Glenn
Published: January 2006

Ecologists have proposed that tree species may coexist by specialising on light environments associated with gaps of different sizes. Remarkably few community‐level studies, however, have actually examined juvenile tree distributions along light availability gradients. Here we describe distributions of juvenile trees in relation to canopy openness in a temperate rainforest, and test the hypothesis that competitive sorting causes coexisting species to overlap less in light environment occupancy than would be expected by chance. Average overlap of species’ interquartile ranges on the canopy openness gradient was tested against a bounded domain null model of community structure which used range‐size criteria to constrain random placement of species optima. Microsite availability was strongly skewed towards low light, with 43% of microsites occurring at <5% canopy openness. We therefore transformed canopy openness values to ranks, so that equal intervals on the transformed gradient represented equal areas of microsite availability. We then calculated the interquartile range (25–75%) of sample ranks occupied by juveniles of each species. About half the assemblage was non‐randomly distributed in relation to canopy openness, providing evidence of niche expression. Average overlap of species’ interquartile ranges did not depart significantly from that predicted by the bounded null model, indicating that community structure in relation to canopy openness was mainly explained by a mid‐domain effect. As predicted by the null model, species’ interquartile range mid‐points were concentrated in the centre of the rank‐transformed gradient, and species richness (overlap of interquartile ranges) peaked close to the median light environment. Most species therefore had intermediate light requirements. The apparent lack of constraints on pairwise overlap suggest that differences in light use are not a prerequisite for tree species coexistence. As far as we are aware, this is the first study to identify a mid‐domain effect on a resource availability axis.
Growing large in a low grade environment: size dependent foraging gain and niche shifts to cannibalism in Arctic char
Authors: Finstad Anders Gravbrøt , Ugedal Ola , Berg Ole Kristian
Published: January 2006

Arctic char (Salvelinus alpinus) living in allopatry in lakes often show a distinct size dimorphism where the large char prey upon small char. We studied the relationship between size scaling of energy intake, total metabolic costs and levels of storage energy related to the niche shift from invertebrate feeding to cannibalism in an alpine Arctic char population. Gill‐net samples consisted of two distinct size modes, small invertebrate feeding char (92–172 mm total length) and large cannibalistic char (265–606 mm total length). Food consumption was estimated for a one year period using a radioactive tracer (137Cs). The energy intake followed a hump‐shaped relationship with fish size for invertebrate feeding char and increased monotonically with size for cannibalistic char. Total metabolic costs increased exponentially with size for both groups. Char feeding in the invertebrate niche had a maximum net energy gain at 140 mm total length with an upper size limit for positive net energy gain at 180 mm. For cannibals the relationship between size and net energy gain formed a hump shaped function with maximum net energy gain at 400 mm and a lower size limit for positive net energy gain at 230 mm. The size at maturation for both small and large char was close to the size for maximum energy gain in their respective niches. Immature individuals close to the upper size limit for positive net energy gain in the invertebrate niche had low levels of storage lipids but tended to have high mass specific growth rates. This may imply a reallocation from reversible (stored) energy to structural (length) growth as a strategy to transform into the size‐range where the cannibalistic niche successfully could be exploited.
Latitudinal gradients of species richness: a test of the geographic area hypothesis at two ecological scales
Authors: Willig Michael R. , Bloch Christopher P.
Published: January 2006

The geographic area hypothesis advances area as the primary cause of latitudinal gradients in diversity. The greater area of tropical zones, it suggests, stimulates speciation, inhibits extinction, and leads to increased species richness compared to the situation in smaller temperate and boreal zones. Because bats exhibit exceptionally strong latitudinal gradients of richness at multiple spatial scales in the New World, they are an appropriate system with which to test the geographic area hypothesis. We used range maps for 250 species of New World bats to estimate species richness in biogeographic zones at two hierarchical spatial scales: biome types and provinces. We then conducted a series of regression analyses to evaluate the ability of area to account for latitudinal gradients in species richness. However, spillover (zonal bleeding) of tropical species into extra‐tropical zones may mask the species‐area relationship and alter perceptions of the latitudinal gradient. To address this issue, we conducted additional analyses excluding tropical species, using a series of increasingly inclusive definitions of tropical ranges. Ecogeographic zones of the New World are not larger at tropical versus extra‐tropical latitudes. Moreover, spillover of tropical species into ecogeographic zones within extra‐tropical regions generally does not diminish the association between richness and area. Nonetheless, the latitudinal gradient of species richness is strong and significant at both ecogeographic scales. Clearly, area does not drive the latitudinal gradient of bat species richness in the New World. In fact, area represents a source of noise rather than a dominant signal at the focal scale of biome types and provinces in the Western Hemisphere.
The functional basis of a primary succession resolved by CSR classification
Authors: Caccianiga Marco , Luzzaro Alessandra , Pierce Simon , Ceriani Roberta M. , Cerabolini Bruno
Published: January 2006

CSR classification aims to apply CSR theory to large numbers of plants in situ, thereby allowing the investigation of communities within a functional context. However, it has only ever been applied to British vegetation, during the development of the technique, and has not yet been used to investigate specific vegetation processes. Here, a vegetation primary succession on a glacier foreland (Rutor glacier, Aosta, Italy) was used as a ‘test bed’ for the hypothesis that CSR classification can distinguish functional shifts during this vegetation process. Morpho‐functional traits were used to calculate CSR coordinates for 45 species throughout the glacier foreland. General functional similarities between species were verified using principal components analysis (PCA). CSR classification demonstrated a functional shift from broadly ruderal pioneers towards stress‐tolerance in late succession. PCA 1 correlated with S and R strategies, confirming this gradient. Till deposited at the retreating glacier terminus provides a substrate that can support faster growing species (with high foliar N contents), but is only tenable to those that can avoid physical disturbance via rapid phenological development (i.e. ruderals). Stress‐tolerance and lower N contents in late succession suggest selection for efficient nutrient use. CSR classification demonstrated that competitive traits were ubiquitous but of much lesser importance than stress‐tolerance or ruderalism (also correlating with PCA 2 and 3). The detailed visualization provided by CSR classification, combined with its mechanistic explanation of community change, demonstrate the promise of this methodology as a quantitative tool for comparative community ecology.
Self‐similarity in species–area relationship and in species abundance distribution
Authors: Pueyo Salvador
Published: January 2006

In an influential paper, Harte et al. highlighted the scaling or ‘self‐similar’ character of the power law species–area relationship (SAR), and used this feature to derive a species abundance distribution (SAD) and an endemics–area relationship. Here I show that their analysis was incorrect and leads to unrealistic results. I develop a different approach and obtain different results, both for SAD and for endemism. In particular, I show that the power law SAR is naturally associated with the power law statistical distribution, which is the only self‐similar distribution and closely matches empirical SADs. The results in this paper shed light on some of the main issues that have been discussed with regard to SARs: their relationship with the lognormal and with the neutral theory, the relative importance of sampling effects vs other mechanisms, and the deviations from a power law. The equations that I develop are simple and easy to apply to field studies.
Size constraints and flower abundance determine the number of interactions in a plant–flower visitor web
Authors: Stang Martina , Klinkhamer Peter G. L. , Van Der Meijden Eddy
Published: January 2006

The number of interactions with flower visitor species differs considerably among insect pollinated plants. Knowing the causes for this variation is central to the conservation of single species as well as whole plant–flower visitor communities. Species specific constraints on flower visitor numbers are seldom investigated at the community level. In this study we tested whether flower size parameters set constraints on the morphology of the potential nectar feeding visitors and thus determine the number of visitor species. We studied three possible constraints: the depth and width of tubular structures hiding the nectar (nectar holder depth and width) and the size of flower parts that visitors can land on (size of the alighting place). In addition we assess the role of flower abundance on this relationship. We hypothesized that the stronger size constraints and the smaller flower abundance, the smaller the number of visitor species will be. Our study of a Mediterranean plant–flower visitor community revealed that nectar holder depth, nectar holder width and number of flowers explained 71% of the variation in the number of visitor species. The size of the alighting place did not restrict the body length of the visitors and was not related to visitor species number. In a second step of the analyses we calculated for each plant species the potential number of visitors by determining for each insect species of the local visitor pool whether it passed the morphological limits set by the plant. These potential numbers were highly correlated with the observed numbers (r2=0.5, p<0.001). For each plant species we tested whether the observed visitors were a random selection out of these potential visitors by comparing the mean of the observed and expected proboscis length distributions. For most plant species the observed mean was not significantly different from the random means. Our findings shed light on the way plant–flower visitor networks are structured. Knowing the constraints on interaction patterns will be an important prerequisite to formulate realistic null models and understand patterns of resource partitioning as well as coevolutionary processes.
Indirect effects of predatory trout on organic matter processing in detritus‐based stream food webs
Authors: S. Greig Hamish , R. McIntosh Angus
Published: January 2006

Indirect effects of predators on basal resources in allochthonous‐based food webs are poorly understood. We investigated indirect effects of predatory brown trout (Salmo trutta) on detritus dynamics in southern beech (Nothofagus spp.) forest streams in New Zealand through predation on the obligate detritivore, Zelandopsyche ingens (Trichoptera, Oeconesidae). Trout presence/absence and Z. ingens density were manipulated in flow‐through tanks to investigate the lethal and sub‐lethal effects of trout on litter processing by Z. ingens. An experiment that allowed trout access to Z. ingens showed trout predation reduced densities of Z. ingens resulting in slower breakdown of coarse particulate organic matter (CPOM) and reduced production of fine particulate organic matter (FPOM). A second experiment that prevented trout access to Z. ingens, but allowed the transmission of trout cues, resulted in no change in litter processing rates in the presence of trout. Litter processing rates were higher in high Z. ingens density treatments compared to low density treatments. Thus, trout effects on litter processing were due to reduced Z. ingens densities, not trout‐induced modifications to Z. ingens feeding behaviour. Field assays of litter processing rates using artificial leaf packs in natural streams showed significant reductions in CPOM loss in trout streams compared to fishless streams. Z. ingens dominated biomass in fishless stream leaf packs, but a facultative shredder, Olinga feredayi, dominated trout stream leaf packs. Thus, the absence of Z. ingens drove differences in processing rates between trout and fishless streams and the indirect effects of trout on litter processing observed in mesocosms were evident in complex, natural food webs. Overall our study provides evidence that predators can influence resource dynamics in donor‐controlled food webs through their effects on consumers.
Species richness destabilizes ecosystem functioning in experimental aquatic microcosms
Authors: Zhang Quan‐Guo , Zhang Da‐Yong
Published: January 2006

The relationship between species diversity and ecosystem stability has long interested ecologists, yet no consensus has been reached and the underlying mechanisms remain unclear. We used five unicellular algal species, cultured in all possible combinations, to assemble microcosms containing 1 to 5 algal species, on which a cold perturbation was imposed. Our aim was to find whether and how species richness begets ecosystem resistance and resilience. In the experiment, the species‐rich communities produced more biomass than the species‐poor ones, either in pre‐, under‐ or post‐perturbation conditions. The positive diversity–biomass relationship was weakened by the perturbation, and fully restored one week after the perturbation. The diverse communities showed greater absolute biomass reduction during the perturbation than did species‐poor systems. Resistance of community, measured by the relative change in biomass from pre‐ to under‐perturbation, decreased with species richness. All the species showed significant reduction in biomass when stressed, without any density compensation among species in diverse communities; and the ratio of biomass change in each species was independent of diversity. The overyielding effect, measured as relative yield total, remained constant from pre‐ to under‐perturbation; and the selection and complementarity effects played equal roles for the biodiversity effect on biomass production, and their relative importance was not altered by the perturbation. These results suggest that similar responses of different species to environmental perturbations may limit the insurance effect of biodiversity, and lead to an inverse diversity–resistance relationship.
A meta‐analysis of tradeoffs between plant tolerance and resistance to herbivores: combining the evidence from ecological and agricultural studies
Authors: Leimu Roosa , Koricheva Julia
Published: January 2006

Resistance and tolerance represent two general strategies of plant defence against herbivores. Since resources available for allocation to defence are limited and resistance and tolerance are likely to serve the same functions for plants, the occurrence of trade offs between these two strategies has been assumed. We review the empirical evidence for tolerance–resistance tradeoffs by means of meta‐analysis of genetic correlations between resistance and tolerance obtained from 31 ecological and agricultural studies published during 1980–2003 and conducted on 17 different plant species. The sign of the relationship between tolerance and resistance differed depending on the type of plants examined. Tolerance and resistance tended to be positively correlated in crops and negatively correlated in wild plants, but the mean correlation coefficients in both plant types were not significantly different from zero. The magnitude of correlations was affected neither by the tolerance measure (reduction in growth or in fitness in damaged plants) nor by the resistance measure used (inverse of damage, antibiosis, antixenosis, or specific resistance trait). In wild plants correlations between resistance and tolerance were significantly negative (r=−0.069) only in studies where resistance was assessed as a specific chemical or mechanical resistance trait, but this correlation is based only on two studies. No difference in the mean resistance–tolerance correlations was found between studies conducted in the field and in the greenhouse; in both cases mean correlations tended to be positive. The results of our analysis indicate that conditions under which a negative association between resistance and tolerance occurs and, thus, the evolution of multiple defensive strategies in plants is constrained, are much more restrictive than previously assumed. However, the currently available studies are still scarce and taxonomically skewed to allow a thorough analysis of sources of variation in resistance–tolerance relationship. Specifically, we need more studies examining the relationship between specific resistance and tolerance traits, studies on perennial plants and under different environmental conditions.
Long‐term prognosis in Crohn's disease: factors that affect quality of life
Authors: CANAVAN C. , ABRAMS K. R. , HAWTHORNE B. , DROSSMAN D. , MAYBERRY J. F.
Published: January 2006

Background

There are many studies investigating quality of life in recently diagnosed patients and following surgery for Crohn's disease, but there are none investigating quality of life changes with disease duration. The response shift model suggests quality of life improves with time following diagnosis.

Aim

To assess how well the model applies to patients with Crohn's disease.

Methods

The Cardiff Crohn's disease database contains data on all patients diagnosed there since 1934. Three hundred and ninety four patients diagnosed before 1 January 1985 were traced and the mortality status on 31 December 2004 established. Two hundred and eleven still living were sent quality of life questionnaires. Two hundred and eighty five questionnaires were sent to patients with varying disease duration attending out‐patient clinics in Leicester.

Results

Eighty‐nine valid replies were received from Cardiff, 63 from Leicester patients diagnosed over 20 years, 69 from Leicester patients diagnosed <10 years. There was no difference in quality of life between newly diagnosed and established patients. Of greatest concern was possible need for ostomy, uncertain nature of disease, and lack of energy. Stepwise regression showed that increased disease severity, older age and smoking adversely affect quality of life.

Discussion

Quality of life is equally poor in patients with established disease as in those newly diagnosed, and directly correlates with disease severity. The response shift model may not be applicable in Crohn's disease.
Review article: complementary and alternative therapies for inflammatory bowel disease
Authors: LANGMEAD L. , RAMPTON D. S.
Published: January 2006

Complementary and alternative medicine includes a wide range of practices and therapies outside the realms of conventional western medicine. Despite a lack of scientific data in the form of controlled trials for either efficacy or safety of complementary and alternative medicine, use by patients with inflammatory bowel disease, particularly of herbal therapies, is widespread and increasing.

There is limited controlled evidence indicating efficacy of traditional Chinese medicines, aloe vera gel, wheat grass juice, Boswellia serrata and bovine colostrum enemas in ulcerative colitis. Encouraging results have also been reported in small studies of acupuncture for Crohn's disease and ulcerative colitis. Contrary to popular belief, natural therapies are not necessarily safe: fatal hepatic and irreversible renal failure have occurred with some preparations and interactions with conventional drugs are potentially dangerous.

There is a need for further controlled clinical trials of the potential efficacy of complementary and alternative approaches in inflammatory bowel disease, together with enhanced legislation to maximize their quality and safety.
Three‐year oral pantoprazole administration is effective for patients with Zollinger–Ellison syndrome and other hypersecretory conditions
Authors: METZ D. C. , COMER G. M. , SOFFER E. , FORSMARK C. E. , CRYER B. , CHEY W. , PISEGNA J. R.
Published: January 2006

Background

Zollinger–Ellison syndrome and idiopathic hypersecretion are gastrointestinal hypersecretory conditions requiring long‐term maintenance.

Aims

The safety and efficacy data for short‐term (6‐month) treatment of Zollinger–Ellison syndrome and idiopathic hypersecretion with oral pantoprazole were previously published. This study extends the initial observations to 3 years.

Methods

The primary efficacy end point for this report was the control of gastric acid secretion in the last hour before the next dose of oral pantoprazole (acid output of <10 mmol/h; <5 mmol/h in subjects with prior acid‐reducing surgery). Dose titration was permitted to a maximum of 240 mg per 24 h.

Results

Twenty‐four subjects completed the study. The acid output of 28 of 34 subjects was controlled at initial enrolment. The mean acid output rates were <10 mmol/h throughout the 36 months of treatment for 90–100% of the patients. The majority of the patients were controlled with b.d. doses of 40 or 80 mg pantoprazole at 36 months (acid output was controlled in 24 of 24 subjects). Pantoprazole was generally well tolerated with minimal adverse events reported.

Conclusions

Maintenance oral pantoprazole therapy up to 3 years at dosages of 40–120 mg b.d. was effective and well tolerated in patients with Zollinger–Ellison syndrome and other hypersecretory conditions.
Review article: non‐biological liver support in liver failure
Authors: LALEMAN W. , WILMER A. , EVENEPOEL P. , VERSLYPE C. , FEVERY J. , NEVENS F.
Published: January 2006

Liver failure, whether acute or acute‐on‐chronic, remains an important cause of morbidity and mortality. The lack of liver detoxification, metabolic and regulatory functions of the liver leads to life‐threatening complications, such as renal failure, altered immune response, hepatic coma and systemic haemodynamic dysfunction, eventually culminating in multiorgan failure.

Current medical therapy involves the management of the precipitating event and treatment of complications until the liver eventually recovers, leaving us with no other treatment options than transplantation if these attempts fail. However, the shortage in cadaveric organs and other transplant‐related problems, have prompted the need for alternative methods to provide liver support.

As liver failure is often potentially reversible, considerable effort has been invested in the development of liver support systems. Currently, most of the experience is available for non‐biological support systems. They represent the focus of this review, which aims to define the goals of liver support, to describe the design of the different existing devices and to analyse the available data to determine their current status in the management of patients with liver failure.
Cost‐effectiveness analysis of lamivudine and adefovir dipivoxil in the treatment of patients with HBeAg‐negative chronic hepatitis B
Authors: BUTI M. , CASADO M. A. , CALLEJA J. L. , SALMERÓN J. , AGUILAR J. , RUEDA M. , ESTEBAN R.
Published: January 2006

Aim

To estimate the cost‐effectiveness over a 4‐year duration of lamivudine and adefovir dipivoxil for patients with hepatitis B ‘e’ antigen‐negative chronic hepatitis B.

Methods

A decision analysis model has been used to perform a cost‐effectiveness analysis of lamivudine and adefovir dipivoxil from the perspective of the Spanish Public Health System. Data were obtained from clinical trials.

Results

For the base‐case, the total estimated cost per patient treated with lamivudine or adefovir dipivoxil for 4 years was €11 457 and €21 939 respectively. Virological response at year 4 for the lamivudine arm was 40.4% and 78.0% for the adefovir dipivoxil arm. The average cost‐effectiveness ratio (cost per responding patient at year 4) was €28 375 for the lamivudine arm and €28 132 for the adefovir dipivoxil arm. The incremental cost‐effectiveness ratio of adefovir dipivoxil vs. lamivudine (cost per additional responding patient with adefovir dipivoxil) was €27 872, demonstrating that this cost was slightly lower than the average cost‐effectiveness ratios of adefovir dipivoxil or lamivudine. The sensitivity analysis demonstrated that the factors that most influence the cost‐effectiveness were the response to adefovir dipivoxil and lamivudine at year 4.

Conclusion

Long‐term treatment with adefovir dipivoxil is a cost‐effective strategy in patients with chronic hepatitis B ‘e’ antigen‐negative hepatitis.
Primary clarithromycin resistance in Italy assessed on Helicobacter pylori DNA sequences by TaqMan real‐time polymerase chain reaction
Authors: DE FRANCESCO V. , MARGIOTTA M. , ZULLO A. , HASSAN C. , VALLE N. D. , BURATTINI O. , CEA U. , STOPPINO G. , AMORUSO A. , STELLA F. , MORINI S. , PANELLA C. , IERARDI E.
Published: January 2006

Background

Helicobacter pylori clarithromycin resistance is increasing worldwide and different mutations are involved in its mechanisms. Recently, molecular methods have been proposed to assess these mutations.

Aim

To assess prevalence of primary clarithromycin resistance in two Italian areas, and the distribution of involved mutations, by using a novel method for real‐time polymerase chain reaction.

Methods

Two hundred and thirty‐two H. pylori‐positive patients undergoing oesophagogastroduodenoscopy in two Italian towns (Rome, centre Italy; Foggia, south Italy) were enrolled. Helicobacter pylori infection was detected by histology, rapid urease and urea breath tests. Clarithromycin resistance was assessed by TaqMan real‐time polymerase chain reaction on paraffin‐embedded antral biopsies.

Results

Primary clarithromycin resistance was detected in 62 (26.7%) patients. Its prevalence did not differ between the two areas (31.5%, centre vs. 23.3%, south; P = 0.17) and between non‐ulcer dyspepsia and peptic ulcer patients (28.4% vs. 20.7%, P = 0.2). The A2143G point mutation was detected in 35 (56.4%) patients, A2142G in 14 (22.6%), A2142C in eight (12.9%), whilst a double mutation (A2143G plus A2142C or A2142G) was present in the remaining five (8.1%) cases.

Conclusions

Our study found that primary clarithromycin resistance is highly prevalent in both central and southern Italy, and that A2143G is the most frequent point mutation involved in these areas.