bluuebunny/crossref_metadata_2025 huggingface dataset:
Facile synthesis of Cu2CoSnS4 nanoparticles exhibiting red-edge-effect: Application in hybrid photonic devices
Authors: Murali Banavoth , Krupanidhi S. B.
Published: October 2013

Cu2CoSnS4 (CCTS) quaternary semiconducting nanoparticles with size distribution from 20 nm to 60 nm were synthesized by one-pot low temperature time and surfactant dependent hydrothermal route. Nanoparticles were characterized structurally and optically. Excitation dependent fluorescence exhibited a dynamic stoke shift referring to the Red-Edge-Effect with peak shifting by a greater magnitude (>100 nm) towards red side, in all the samples. Hybrid devices, fabricated from CCTS nanoparticle inorganic counterparts benefitting from the conjugation of organic P3HT polymer matrix, were demonstrated for photodetection under infra-red and A.M 1.5 solar light illuminations. Faster rise and decay constants of 37 ms and 166 ms, with one order photocurrent amplification from 1.6 × 10−6 A in the dark to 6.55 × 10−5 A, upon the 18.50 mW cm−2 IR lamp illumination, make CCTS a potential candidate for photodetector and photovoltaic applications.
Anomaly close to an electronic topological semimetal-insulator transition in elemental fcc-Yb under pressure
Authors: Enderlein Carsten , Ramos Scheilla M. , Bittencourt Magda , Continentino Mucio A. , Brewer William , Baggio-Saitovich Elisa
Published: October 2013

The Lifshitz-type semimetal-insulator transition, which is a transition of the electronic topology, has been considered as the most fundamental metal-insulator transition. Here, we present resistivity measurements under pressure in the vicinity of the quantum critical point of fcc Yb. We apply a previously suggested scaling for this type of transition and identify its universality class. Moreover, we observe an anomaly in the screening coefficient A of the T2 term in the resistivity at low temperatures in the metallic phase. We suggest an interpretation of this phenomenon as an effect of doping by Ca impurities unintentionally present in the Yb crystals. The observed behavior may very well be applicable to any doped system in the vicinity of such a transition.
The World System of Englishes
Authors: Mair Christian
Published: October 2013

Contact between and mutual influences among varieties of standard and non-standard English have always been a central concern in research on World Englishes. In a mobile and globalising world such contacts are by no means restricted to diffusion of features in face-to-face interaction, across contiguous territories in space or up and down the sociolinguistic scale. In order to better represent and understand the complex relationships obtaining between varieties of standard and non-standard English in the contemporary “English language complex” (McArthur 2003: 56; Mesthrie and Bhatt 2008: 1–3), the present paper proposes a new theoretical model, based on language systems theory (de Swaan 2002, 2010). While the model is not designed to supersede existing alternatives, such as the Kachruvian (1982) Circles, it will nevertheless complement them in important ways, chiefly because it is better equipped to handle uses of English in domains beyond the post-colonial nation state. The “World System of Englishes” model was developed in the course of the author’s work on the use of pidgins and creoles in web forums serving the post-colonial West African and Caribbean diasporas. The way Nigerian Pidgin figures in the creation of a globalised digital ethnolinguistic repertoire will hence serve as an illustration of its usefulness.
African Bermudian English and the Caribbean connection
Authors: Eberle Nicole , Schreier Daniel
Published: October 2013

Bermudian English (BerE) is one of the least documented varieties of English that has undergone full nativisation. The only source we are aware of is Ayres (1933), who provides an overview of some selected phonological features. The present paper has two aims: first, to provide a preliminary morphosyntactic profile of African Bermudian English (ABerE) and to anchor this variety in the quickly emerging canon of lesser-known varieties of English around the world (Schreier et al. 2010), and second, to gain some first typological insights whether or not it aligns with English in the Caribbean (and if so, with which varieties), as has been claimed by some sources (e.g. Trudgill 2002). With this aim, we report some first findings from a fieldwork study on the island and in a later step compare these with selected Caribbean varieties — Bahamian English (BahE), Bajan, Jamaican English, and Vincentian Creole, as reported in the Electronic World Atlas of Varieties of English (Kortmann and Lunkenheimer 2011). We argue that morphosyntactic similarities and differences between the varieties are explained by the Bermudian community’s sociohistorical and sociolinguistic contexts, including settlement patterns, population demographics, and peopling, and that the emergence and origins of a stable localised variety of (A)BerE need to be approached with reference to the historical connections between Bermuda and the communities that provided donor varieties. We further argue in favor of a two-way transfer pattern: Caribbean Englishes are likely to have influenced the evolution of English on Bermuda, while BerE itself was an influential input variety in other locations (particularly the Bahamas and the Turks and Caicos Islands).
Syntactic effects of feature-driven movement in Russian speakers’ L2 Chinese grammars
Authors: Dugarova Esuna
Published: October 2013

Availability of wh-topicalization in Chinese raises a question as to whether a whtopic in L2 Chinese is derived by feature-driven movement and, if it is, whether such movement is subject to syntactic constraints. The current study tests the sensitivity of very advanced Russian speakers’ L2 Chinese wh-topicalization to a complex NP island and reconstruction, which are taken as a diagnostic of movement. The results of an acceptability judgement test and a multiple choice interpretation test show that L2 Chinese grammars are constrained by a complex NP island and reconstruction, which provides empirical evidence that L2 Chinese wh-topicalization involves movement driven by an uninterpretable [+Top] feature.
Translation and theatre
Authors: Marinetti Cristina
Published: October 2013

The last two decades have seen an increasing interest from different quarters in exploring the territory that exists between translation and theatre. Examining discussions of the nature of drama and theatre—that see them as performative rather than representative entities (Worthen 2003;Schechner 2002)—this article argues for a rethinking of the interdisciplinary relations between translation and theatre in the context of wider debates over the value of interdisciplinarity in translation studies (Pym 1998;Chesterman 2010;Bassnett 2012). Drawing on the contributions to this special issue, the social dimension of translation and the performative nature of culture are brought to the fore as productive new ways of studying translation in the theatre as a performative and social as well as a linguistic practice.
Surtitles take the stage in Franco-Canadian theatre
Authors: Ladouceur Louise
Published: October 2013

Faced with the need to expand their audience, small Franco-Canadian theatre companies are experimenting with various on-stage translative strategies, such as surtitles, to reach audiences with diverse linguistic and cultural profiles. Not only do they explore their bilingualism in plays that incorporate Canada’s two official languages, they enhance the bilingual aesthetics of the original play with the use of surtitles. In addition to conventional surtitles translating the source text delivered orally on stage, creative surtitles transmit new messages and thus multiply the possible readings generated by the performance. Thus, translation achieves a certain autonomy within the theatre production and, in doing so, redefines its function while challenging the existing theoretical models applied to the translation of dramatic texts.
Professing translation
Authors: Johnston David
Published: October 2013

Drawing on scholarship in translation ethics (Berman 1992;Cronin 2003) and performance studies (Conquergood 2002;Jackson 2004), this article approaches translation in the theatre from the double perspective of theory and practice. Professing translation as a model for the resolution of entrenched binaries (scholar/artist; theoretician/practitioner), the author sees the practice of translating for performance not just as a method of discovery or a hermeneutic tool but also as a mode of reflection that brings together both “readerly” and “writerly” approaches to text (Barthes 1974). By drawing on the experience of writing translations of García Lorca for the Belgrade Theatre, Calderón for the Royal Shakespeare Company, and Lope de Vega for the Watermill Theatre and the Washington Shakespeare Theatre, the article attempts to characterise such translation as an act of physical imagination, of a holistic understanding of both language and performance, into which textuality is incorporated and by which it is superseded.
Propofol Limits Microglial Activation after Experimental Brain Trauma through Inhibition of Nicotinamide Adenine Dinucleotide Phosphate Oxidase
Authors: Luo Tao , Wu Junfang , Kabadi Shruti V. , Sabirzhanov Boris , Guanciale Kelsey , Hanscom Marie , Faden Juliane , Cardiff Katherine , Bengson Charles Jeremy , Faden Alan I.
Published: October 2013

Background:

Microglial activation is implicated in delayed tissue damage after traumatic brain injury (TBI). Activation of microglia causes up-regulation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, with the release of reactive oxygen species and cytotoxicity. Propofol appears to have antiinflammatory actions. The authors evaluated the neuroprotective effects of propofol after TBI and examined in vivo and in vitro whether such actions reflected modulation of NADPH oxidase.

Methods:

Adult male rats were subjected to moderate lateral fluid percussion TBI. Effect of propofol on brain microglial activation and functional recovery was assessed up to 28 days postinjury. By using primary microglial and BV2 cell cultures, the authors examined propofol modulation of lipopolysaccharide and interferon-γ–induced microglial reactivity and neurotoxicity.

Results:

Propofol improved cognitive recovery after TBI in novel object recognition test (48 ± 6% for propofol [n = 15] vs. 30 ± 4% for isoflurane [n = 14]; P = 0.005). The functional improvement with propofol was associated with limited microglial activation and decreased cortical lesion volume and neuronal loss. Propofol also attenuated lipopolysaccharide- and interferon-γ–induced microglial activation in vitro, with reduced expression of inducible nitric oxide synthase, nitric oxide, tumor necrosis factor-α, interlukin-1β, reactive oxygen species, and NADPH oxidase. Microglial-induced neurotoxicity in vitro was also markedly reduced by propofol. The protective effect of propofol was attenuated when the NADPH oxidase subunit p22phox was knocked down by small interfering RNA. Moreover, propofol reduced the expression of p22phox and gp91phox, two key components of NADPH oxidase, after TBI.

Conclusion:

The neuroprotective effects of propofol after TBI appear to be mediated, in part, through the inhibition of NADPH oxidase.
Lead resistance in micro-organisms
Authors: Jarosławiecka Anna , Piotrowska-Seget Zofia
Published: October 2013

Lead (Pb) is an element present in the environment that negatively affects all living organisms. To diminish its high toxicity, micro-organisms have developed several mechanisms that allow them to survive exposure to Pb(II). The main mechanisms of lead resistance involve adsorption by extracellular polysaccharides, cell exclusion, sequestration as insoluble phosphates, and ion efflux to the cell exterior. This review describes the various lead resistance mechanisms, and the regulation of their expression by lead binding regulatory proteins. Special attention is given to the Pbr system fromCupriavidus metalliduransCH34, which involves a unique mechanism combining efflux and lead precipitation.
Triplex real‐time polymerase chain reaction assay for detection and quantification of norovirus (GIandGII) and sapovirus
Authors: Niwa Shoichi , Tsukagoshi Hiroyuki , Ishioka Taisei , Sasaki Yoshiko , Yoshizumi Masakazu , Morita Yukio , Kimura Hirokazu , Kozawa Kunihisa
Published: October 2013

To improve detection of norovirus (NoVGI, NoVGII) and sapovirus (SaV), a simultaneous quantitative RT‐PCR method was established. This triplex real‐time PCR method was evaluated using a combination of optimized specific primers and probes. The performance of the developed PCR assay was equivalent to that of monoplex real‐time PCR across a broad dynamic range of 102–107copies/assay using plasmid DNA standards. The limit of detection was 102copies/assay. The quantitative value was comparable with that of monoplex real‐time PCR of stool samples. Our triplex real‐time PCR is useful for detection of NoV and SaV infections.
Trophic niche flexibility in Glossophaga soricina: how a nectar seeker sneaks an insect snack
Authors: Clare Elizabeth L. , Goerlitz Holger R. , Drapeau Violaine A. , Holderied Marc W. , Adams Amanda M. , Nagel Juliet , Dumont Elizabeth R. , Hebert Paul D. N. , Brock Fenton M.
Published: October 2013

Omnivory enables animals to fill more than one trophic niche, providing access to a wider variety of food resources with potentially higher nutrient value, particularly when resources become scarce. Animals can achieve omnivory using different strategies, for example opportunistic foraging, or switching between multiple trophic niches.

The Neotropical bat Glossophaga soricina (Pallas, 1766) is a common and widespread species known for nectar feeding, but it also eats fruit and insects. Approaching stationary objects (flowers and fruits) or moving objects (insects) poses different sensory tasks and should require different echolocation behaviours. Here we tested the contrasting hypothesis that G. soricina can approach both stationary and moving objects using the same echolocation behaviour, thus feeding at different trophic levels by a single sensory mechanism.

Using DNA barcoding, we demonstrate that G. soricina eats beetles (Coleoptera), flies (Diptera) and noctuid moths with bat‐detecting ears. Laboratory observations show that G. soricina actively hunts for prey so insect consumption does not appear to be opportunistic. After capture, individuals consumed prey while perched and manipulated them with jaw, thumb, wrist and wing movements, but food handling was longer and chewing rate slower than in obligate insectivores.

In contrast to most insectivorous bats, the echolocation calls of G. soricina are of high frequency and low intensity, and G. soricina did not produce feeding buzzes when approaching insects. An acoustic model of detection distances shows that its low‐intensity calls fail to trigger the auditory neurons of eared moths, allowing G. soricina to overcome auditory prey defences.

Individuals achieved niche flexibility using a unique but generalist behavioural approach rather than employing two different specialist methods. Our findings provide a novel insight into the functional mechanisms of insect capture in G. soricina and highlight the importance of considering niche flexibility in classifying trophic links in ecological communities.
Sapwood capacitance is greater in evergreen sclerophyll species growing in high compared to low‐rainfall environments
Authors: Richards Anna E. , Wright Ian J. , Lenz Tanja I. , Zanne Amy E.
Published: October 2013

The capacitative release of water from sapwood allows photosynthesis to continue for longer into dry periods, both diurnally and seasonally. However, costs of high capacitance include increased vulnerability to xylem cavitation. The degree of reliance on stored water is predicted to differ among environments as a result of this trade‐off.

Xylem water potential and sapwood capacitance were measured on 32 evergreen sclerophyll shrub and tree species in eastern Australia, sampled from four sites contrasting in soil nutrients and rainfall.

Capacitance calculated over species' typical shoot water potential operating range was threefold higher for species from high compared to low‐rainfall sites, and 1·5‐fold higher for species from high compared to low‐nutrient sites.

To determine whether these site differences were related to extrinsic (e.g. water availability) or intrinsic (e.g. species anatomical construction) factors, we calculated capacitance at two common operating ranges; that is, the mean range in water potential observed for low‐rainfall species (ΔΨlow rain) and the mean range for high‐rainfall species (ΔΨhigh rain). While no difference was seen between low‐ and high‐rainfall species in release of stored water across ΔΨhigh rain, across ΔΨlow rain, the high‐rainfall species released 38% more stored water than low‐rainfall species. Presumably these differences reflect underlying differences in anatomy, such as wood density, which was lower in high‐rainfall species.

These results accord with predictions that (i) species from wetter sites exhibit less negative stem water potentials and high sapwood capacitance, enabling them to maintain function under variable conditions characterized by many short, dry periods, while (ii) species from low‐rainfall sites have wood anatomies conferring tolerance to very low water potentials, with low sapwood capacitance, enabling them to survive longer through unpredictable and extended periods of low rainfall. The finding that the degree to which species rely on stem‐stored water varies with site rainfall suggests that changes in drought regimes (e.g. incidence, duration and severity) under future climates could differentially affect species according to the capacitance properties of their woody tissues.
Exercise changes behaviour
Authors: Sinclair Elektra L. E. , de Souza Carolina R. Noronha , Ward Ashley J. W. , Seebacher Frank
Published: October 2013

Exercise, which may be defined as bodily movement produced by the contraction of skeletal muscle and which increases energy expenditure above basal levels, is essential for fitness‐related activities such as foraging, migration and dispersal. The frequency with which individuals engage in exercise depends on a range of intrinsic and environmental factors. Exercise itself can modify behaviour by inducing endocrine changes and by a training effect that increases physiological capacities.

Here, we test the hypothesis that exercise changes behaviour and that there is positive feedback so that performing exercise increases the likelihood of performing exercise‐related behaviours.

We show that there was a training effect that improved sustained swimming performance of mosquitofish (Gambusia holbrooki) exposed to chronic exercise in flowing water for 4 weeks compared to sedentary controls. Exercised fish also became bolder and were quicker to leave a refuge, showed an increasing tendency to explore unfamiliar environments, and were more aggressive than sedentary fish. These physiological and behavioural changes reverted back to control levels when exercised fish assumed a sedentary lifestyle again.

We used the calcium channel blocker nifedipine to decrease swimming performance of exercised fish to control levels, which allowed us to determine whether increased locomotor capacity per se influences behaviour. We show that reducing the swimming performance of exercised fish also reduced exploration and aggression, but it did not affect the latency to leave a refuge (boldness).

Our data show that behavioural phenotypes are not fixed. Exercise changes behaviour and may thereby alter interactions between individuals and dispersal. Environmental changes that demand increased levels of exercise induce behavioural responses that are likely to increase the success of individuals under these changed conditions.
Fortune favours the bold: a higher predator reduces the impact of a native but not an invasive intermediate predator
Authors: Barrios‐O'Neill Daniel , Dick Jaimie T. A. , Emmerson Mark C. , Ricciardi Anthony , MacIsaac Hugh J. , Alexander Mhairi E. , Bovy Helene C.
Published: October 2013

Emergent multiple predator effects (MPEs) might radically alter predictions of predatory impact that are based solely on the impact of individuals. In the context of biological invasions, determining if and how the individual‐level impacts of invasive predators relates to their impacts in multiple‐individual situations will inform understanding of how such impacts might propagate through recipient communities.

Here, we use functional responses (the relationship between prey consumption rate and prey density) to compare the impacts of the invasive freshwater mysid crustaceanHemimysis anomalawith a native counterpartMysis salemaaiwhen feeding on basal cladoceran prey (i) as individuals, (ii) in conspecific groups and (iii) in conspecific groups in the presence of a higher fish predator,Gasterosteus aculeatus.

In the absence of the higher predator, the invader consumed significantly more basal prey than the native, and consumption was additive for both mysid species – that is, group consumption was predictable from individual‐level consumption.

Invaders and natives were themselves equally susceptible to predation when feeding with the higher fish predator, but anMPEoccurred only between the natives and higher predator, where consumption of basal prey was significantly reduced. In contrast, consumption by the invaders and higher predator remained additive.

The presence of a higher predator serves to exacerbate the existing difference in individual‐level consumption between invasive and native mysids. We attribute the mechanism responsible for theMPEassociated with the native to a trait‐mediated indirect interaction, and further suggest that the relative indifference to predator threat on the part of the invader contributes to its success and impacts within invaded communities.
Changes in breeding phenology and population size of birds
Authors: Dunn Peter O. , Møller Anders P.
Published: October 2013

Although the phenology of numerous organisms has advanced significantly in response to recent climate change, the life‐history and population consequences of earlier reproduction remain poorly understood.

We analysed extensive data on temporal change in laying date and clutch size of birds from Europe and North America to test whether these changes were related to recent trends in population size.

Across studies, laying date advanced significantly, while clutch size did not change. However, within populations, changes in laying date and clutch size were positively correlated, implying that species which advanced their laying date the most were also those that increased their clutch size the most.

Greater advances in laying date were associated with species that had multiple broods per season, lived in nonagricultural habitats and were herbivorous or predatory. The duration of the breeding season increased for multibrooded species and decreased for single‐brooded species. Changes in laying date and clutch size were not related to changes in population size (for resident or migratory species).

This suggests that, across a wide variety of species, mismatches in the timing of egg laying or numbers of offspring have had relatively little influence on population size compared with other aspects of phenology and life history.
Two‐sex matrix models in assessing population viability: when do male dynamics matter?
Authors: Gerber Leah R. , White Easton R.
Published: October 2013

While most demographic population models used in conservation rely on female vital rates, recent empirical evidence suggests that male dynamics should be included in population models used for assessing extinction risk.

UsingCalifornia sea lionsZalophus californianusas an applied example, we demonstrate that there are situations in which two‐sex models are more appropriate than the commonly used female‐based model.

Two‐sex models are relevant in cases where vital rates for sexes differ and for polygamous species such as sea lions. Vital rates targeted for management may therefore respond differently for males and females and for different assumptions about sex ratio.

Synthesis and applications. Conservation biologists should carefully consider the social structure and sex ratio of focal species in order to determine whether a two‐sex matrix model will yield more accurate estimates of extinction risk than standard one‐sex models.
Learning the ropes: mussel spat ropes improve fish and shrimp passage through culverts
Authors: David Bruno O. , Tonkin Jonathan D. , Taipeti Kristopher W. T. , Hokianga Hayden T.
Published: October 2013

Culvert pipes are regularly used around the world for conveying stream flows underground, through embankments or under road crossings. Installation of these features can have significant negative effects on the passage of freshwater biota and potentially exclude many species from large areas of river networks.

We investigated the installation of mussel spat ropes as a potentially rapid and cost‐effective tool for improving passage of freshwater biota through culvert pipes where internal barrel conditions impede passage. We assessed passage success for two fish species, juvenile rainbow trout Oncorhynchus mykiss (Walbaum 1972) and adult inanga Galaxias maculatus (Jenyns 1842), and one migratory shrimp, Paratya curvirostris (Heller 1862), through culverts of differing length (3 and 6 m), slope (1·5 and 3°) and flow (0·24 and 0·75 L s−1). We hypothesized that ropes would enhance the passage success of these three species, but success rates would differ between species and trial combinations.

Ropes resulted in a reduced water velocity within culvert barrels and significantly improved passage success for all three species. Shrimp benefited most by the presence of ropes, being unable to negotiate any of the pipe combinations in their absence, but exhibiting varying rates of success across all combinations with their presence. Both G. maculatus and O. mykiss were able to negotiate some of the non‐roped pipe combinations, but as the level of difficulty increased, successful passage was only achieved with the ropes present.

Synthesis and applications. We conclude that this relatively inexpensive and easy‐to‐install tool has the potential to substantially improve passage for a range of aquatic biota through various culvert scenarios. We consider that ropes would be particularly useful in situations where internal culvert access is difficult and where various culvert parameters (slope, flow, length) result in internal barrel hydraulics that would normally limit or exclude passage of aquatic biota.
EDITOR'S CHOICE: Stepping stones are crucial for species' long‐distance dispersal and range expansion through habitat networks
Authors: Saura Santiago , Bodin Örjan , Fortin Marie‐Josée
Published: October 2013

Climate and land‐use changes will require species to move large distances following shifts in their suitable habitats, which will frequently involve traversing intensively human‐modified landscapes. Practitioners will therefore need to evaluate and act to enhance the degree to which habitat patches scattered throughout the landscape may function as stepping stones facilitating dispersal among otherwise isolated habitat areas.

We formulate a new generalized network model of habitat connectivity that accounts for the number of dispersing individuals and for long‐distance dispersal processes across generations. By doing so, we bridge the gap between complex dynamic population models, which are generally too data demanding and hence difficult to apply in practical wide‐scale decision‐making, and simpler static connectivity models that only consider the amount of habitat that can be reached by a single average disperser during its life span.

We find that the loss of intermediate and sufficiently large stepping‐stone habitat patches can cause a sharp decline in the distance that can be traversed by species (critical spatial thresholds) that cannot be effectively compensated by other factors previously regarded as crucial for long‐distance dispersal (fat‐tailed dispersal kernels, source population size).

We corroborate our findings by showing that our model largely outperforms previous connectivity models in explaining the large‐scale range expansion of a forest bird species, the Black Woodpecker Dryocopus martius, over a 20‐year period.

The capacity of species to exploit the opportunities created by networks of stepping‐stone patches largely depends on species‐specific life‐history traits, suggesting that species assemblages traversing fragmented landscapes may be exposed to a spatial filtering process driving long‐term changes in community composition.

Synthesis and applications. Previous static connectivity models seriously underestimate the importance of stepping‐stone patches in sustaining rare but crucial dispersal events. We provide a conceptually broader model that shows that stepping stones (i) must be of sufficient size to be of conservation value, (ii) are particularly crucial for the spread of species (either native or invasive) or genotypes over long distances and (iii) can effectively reduce the isolation of the largest habitat blocks in reserves, therefore largely contributing to species persistence across wide spatial and temporal scales.
Complementary impacts of small rodents and semi‐domesticated ungulates limit tall shrub expansion in the tundra
Authors: Ravolainen Virve T. , Bråthen Kari Anne , Yoccoz Nigel G. , Nguyen Julie K. , Ims Rolf A.
Published: October 2013

While shrubs appear to be expanding in Arctic tundra due to climatic warming, patches of tall shrubs in riparian habitats are most likely to colonize new areas. Shrub recruits outside established patches represent the forefront of area expansion, but their dynamics may be sensitive to the action of several herbivore species. The empirical evidence for how different‐sized herbivores affect recruits of tall shrubs is lacking. Moreover, although management and natural population dynamics of herbivores happens at landscape and regional scales, field research on herbivore impacts on shrubs seldom covers these scales.

Reindeer management and different rodent population dynamics result in regional variation in herbivore abundances in arctic Norway. We conducted an herbivore exclusion experiment, covering three low‐arctic river catchments with contrasting herbivore abundances. We assessed the impacts of small rodents and reindeer on growth, and survival of willow Salix spp. recruits after 3 years of herbivore exclusion.

As expected, the Salix recruits increased in sizes and had lower mortality when released from herbivores. Both types of herbivores had strong impacts on size and survival of Salix recruits.

Spatially contrasting results were consistent with regional differences in the abundance of reindeer and rodents; herbivore impacts on shrubs were found when at least one type of herbivore was abundant. However, the impact was not independent of herbivore species. While both browsing from reindeer and rodents pruned the recruits and prevented them from escaping the field layer, the rodents also inflicted substantial mortality and thus thinned the stand of recruits.

Synthesis and applications. Sympatric populations of rodents and reindeer have strongly complementary impacts on shrub recruits and may limit the expansion potential of tall shrubs even in the most productive habitats of arctic tundra. The spatial correspondence between shrub recruits performance and herbivore abundances, found after a short time period, suggests that the extent of tall shrub expansion in tundra is contingent on current variation and future trends in herbivore populations. In areas where humans control large herbivore populations, management may opt to counteract climate‐driven shrub expansion also in habitats that are most prone to such expansion.
Phenotypic plasticity promotes persistence following severe events: physiological and morphological responses of seagrass to flooding
Authors: Maxwell Paul S. , Pitt Kylie A. , Burfeind Dana D. , Olds Andrew D. , Babcock Russell C. , Connolly Rod M.
Published: October 2013

Severe events such as floods or cyclones can have large ecological effects on the structure and functioning of ecosystems. The capacity of an ecosystem to adapt to, or absorb, the effects of a severe event depends on the severity and longevity of the event and the tolerance of the species present.

Seagrasses exhibit phenotypic plasticity at the plant to meadow scale through a variety of physiological and morphological acclimations to light stress to enhance photosynthetic capacity. These acclimations provide early warning of the possible risk of larger scale seagrass loss and can therefore be used in predicting how ecosystems might respond to severe events.

The physiological and morphological responses of 12 seagrass (Zostera muelleri) meadows to a severe flood were examined to test two main hypotheses: (i) that the physiological and morphological characteristics of seagrass would differ between meadows along the established chronic water quality gradient, in a pattern consistent with prior acclimations which have been shown to enhance photosynthetic capacity and (ii) that physiological and morphological responses to the flood would differ between meadows in a manner consistent with their position along the water quality gradient.

Meadows had different physiological and morphological characteristics across the water quality gradient, with meadows subject to chronically poorer water quality exhibiting characteristics consistent with those that maximize photosynthetic capacity. Despite a large discrepancy in impact among meadows, all meadows sampled responded consistently to the flood, exhibiting only physiological changes with no significant reduction in biomass. This suggests that photoacclimation to chronically poor conditions can enable seagrasses to withstand the effects of severe events, such as floods.

Synthesis. Phenotypic plasticity in habitat‐forming species can result in a large variation in their responses to severe events, such as floods or cyclones. Acclimation to prior poor environmental conditions can promote persistence in habitat‐forming species, such as seagrasses, following severe events. The measurement of phenotypic characteristics along an impact gradient can therefore provide an indication of the response of habitat‐forming species to severe events.
Different combinations of multiple defence traits in an extrafloral nectary‐bearing plant growing under various habitat conditions
Authors: Yamawo Akira , Tagawa Jun , Hada Yoshio , Suzuki Nobuhiko
Published: October 2013

The effects of multiple defence traits on herbivory under different abiotic conditions have not been reported in the literature. To clarify the relations between plant defence traits and abiotic factors in the field, we investigated the plasticity of multiple defence traits in young Mallotus japonicus growing in three habitat conditions: open sites, forest edges and treefall gaps.

The plants used multiple defence traits differently in three habitats. At open sites, trichomes, pellucid dots and extrafloral nectaries (EFNs) were expressed better than at the treefall gaps, but food bodies (lipid‐rich particles) were fewer. Fewer ants were observed on the plants at open sites than on plants in other habitats.

Leaves collected from the open sites were consumed less by the generalist herbivore, Spodoptera litura, than leaves collected from the other habitats. The effect of ants on herbivore exclusion was not readily apparent at open sites. Light intensity at the open sites was high. Soil water contents were low.

Tolerance was greater in the forest edge condition, where light intensity and soil water contents were intermediate.

Synthesis. The defence tactics of EFN‐bearing plants in the field must be determined considering the complex effects of different abiotic factors. Each plant can change its combination of defence traits in response to abiotic habitat conditions.
Beyond nectar sweetness: the hidden ecological role of non‐protein amino acids in nectar
Authors: Nepi Massimo
Published: October 2013

Studies from the last decade clearly demonstrate that nectar is much more than just a simple alimentary reward for pollinators. Considerable progress has been made in recent years with regard to the chemical ecology of nectar, demonstrating unequivocally that its chemistry is strongly involved in the interactions between plants and a larger variety of organisms – from bacteria to fungi and animals – than previously thought. As far as plant–pollinator relationships are concerned, attention has recently been directed towards secondary compounds, mainly alkaloids that are able to induce a wide range of behavioural and physiological responses in floral visitors. Nonetheless the study of some other secondary compounds, such as non‐protein amino acids (NPAAs), has been neglected. The roles of these substances in nectar are still unknown although several ecological and physiological functions have been attributed to a number of NAAs in both animals and plants in several ecological and physiological contexts.

The existence of NPAAs in floral nectar was first reported in early surveys of nectar composition dating from the 1970s. Since that time, only a very few papers have mentioned the presence of these compounds in nectar, but without any hypothesis relating to their ecological role and their putative effect on flower visitors. This appears surprising considering that interaction with other organisms is a recognized function of NPAAs in plants.

Here, after exploring the multiple roles of NPAAs at the community level and focusing on the more recent advances in nectar chemistry and ecology, I review the small body of literature relating to the presence of NPAAs in nectar before outlining some ecological roles in the light of complex, nectar‐mediated, plant–animal interactions that have been recognized recently for other nectar secondary compounds based also on data and information obtained for other biological systems (from arthropods to humans).

Synthesis. By integrating data obtained from both literature and field observations, I have arrived at the proposal that non‐protein amino acids in nectar may contribute to the plant–insect network of interactions in a number of ways: by affecting the physiology of the nervous system of the insect, regulating nectar intake through phagostimulation and promoting muscle function during flight. Confirmation of these hypotheses is needed in order to reinforce the concept that plants are able to affect the foraging behaviour of insects through nectar chemistry, thereby eventually optimizing their pollination effectiveness.
The provision of weight management advice: An investigation into occupational therapy practice
Authors: Lang Jessica , James Carole , Ashby Samantha , Plotnifkoff Ronald , Guest Maya , Kable Ashley , Collins Clare , Snodgrass Suzanne
Published: October 2013

Background/aim

Obesity affects more than half the Australian population and has become epidemic throughout the world. Little is known regarding occupational therapy interventions with clients who are overweight or obese. This study aimed to identify occupational therapy practice in relation to the provision of weight management. This was part of a larger study investigating health professional practice.

Methods

A cross‐sectional study design using a self‐administered, purpose‐designed survey was employed to identify the current practices of occupational therapists working in a regional area of New South Wales, Australia. Participants were recruited via email or mail as publically available.

Results

Fifty‐one occupational therapists anonymously completed the survey. Results revealed that 53% (n = 26) of respondents did not consider weight management to be within their scope of practice or their workplace role description. The most common intervention was the provision of physical activity advice (65.2%; n = 30). Dietary advice was provided by 20.8% (n = 10), while 77% (n = 32) referred onto dietitian services. During entry‐level occupational therapy education, only 7.8% (n = 4) had received weight management advice education. Completion of postgraduate professional development training in this area was reported by 14% (n = 7) of respondents.

Conclusion

This study provides insight into the current practices of Australian occupational therapists in relation to the provision of weight management advice. This research displays a need to acknowledge both a generic and a discipline‐specific role for the provision of healthy lifestyle interventions. This may be achieved through better access to education during entry‐level programmes and in the workplace.
Aberrant Rac1–mineralocorticoid receptor pathways in salt‐sensitive hypertension
Authors: Kawarazaki Wakako , Fujita Toshiro
Published: October 2013

According to Guyton's model, impaired renal sodium excretion plays a key role in the increased salt sensitivity of blood pressure (BP). Several factors contribute to impaired renal sodium excretion, including the sympathetic nervous system, the renin–angiotensin system and aldosterone. Accumulating evidence suggests that abnormalities in aldosterone and its receptor (i.e. the mineralocorticoid receptor (MR)) are involved in the development of salt‐sensitive (SS) hypertension.

Patients with metabolic syndrome often exhibit hyperaldosteronism and are susceptible to SS hypertension. Aldosterone secretion from the adrenal glands is not suppressed in obese hypertensive rats fed a high‐salt diet because of the abundant production of adipocyte‐derived aldosterone‐releasing factors, which are independent of the negative feedback regulation of aldosterone secretion by the renin–angiotensin–aldosterone system. Increased plasma aldosterone levels lead to SS hypertension via MR activation in the kidney.

Renal MR activity is increased in Dahl salt‐sensitive rats fed a high‐salt diet, despite the appropriate suppression of plasma aldosterone levels. In this rat strain, activation of MR in the distal nephron causes salt‐induced hypertension. This paradoxical response of the MR to salt loading can be attributed to activation of Rac1, a small GTPase. In the presence of aldosterone, activated Rac1 synergistically and directly activates MR in a ligand‐independent manner. Thus, Rac1 activation in the kidney determines the salt sensitivity of BP. Together, the available evidence suggests that the aberrant Rac1–MR pathway plays a key role in the development of SS hypertension.
Measuring up to speech intelligibility
Authors: Miller Nick
Published: October 2013

Improvement or maintenance of speech intelligibility is a central aim in a whole range of conditions in speech–language therapy, both developmental and acquired. Best clinical practice and pursuance of the evidence base for interventions would suggest measurement of intelligibility forms a vital role in clinical decision‐making and monitoring. However, what should be measured to gauge intelligibility and how this is achieved and relates to clinical planning continues to be a topic of debate. This review considers the strengths and weaknesses of selected clinical approaches to intelligibility assessment, stressing the importance of explanatory, diagnostic testing as both a more sensitive and a clinically informative method. The worth of this, and any approach, is predicated, though, on awareness and control of key design, elicitation, transcription and listening/listener variables to maximize validity and reliability of assessments. These are discussed. A distinction is drawn between signal‐dependent and ‐independent factors in intelligibility evaluation. Discussion broaches how these different perspectives might be reconciled to deliver comprehensive insights into intelligibility levels and their clinical/educational significance. The paper ends with a call for wider implementation of best practice around intelligibility assessment.
Secreted single‐stranded DNA is involved in the initial phase of biofilm formation by Neisseria gonorrhoeae
Authors: Zweig Maria , Schork Sabine , Koerdt Andrea , Siewering Katja , Sternberg Claus , Thormann Kai , Albers Sonja‐Verena , Molin Søren , van der Does Chris
Published: October 2013

Neisseria gonorrhoeae is an obligate human pathogen that colonizes the genital tract and causes gonorrhoea. Neisseria gonorrhoeae can form biofilms during natural cervical infections, on glass and in continuous flow‐chamber systems. These biofilms contain large amounts of extracellular DNA, which plays an important role in biofilm formation. Many clinical isolates contain a gonococcal genetic island that encodes a type IV secretion system (T4SS). The T4SS of N. gonorrhoeae strain MS11 secretes ssDNA directly into the medium. Biofilm formation, studied in continuous flow‐chamber systems by confocal laser scanning microscopy (CLSM), was strongly reduced, especially in the initial phases of biofilm formation, in the presence of Exonuclease I, which specifically degrades ssDNA or in a ΔtraB strain that does not secrete ssDNA. To specifically detect ssDNA in biofilms using CLSM, a novel method was developed in which thermostable fluorescently labelled ssDNA‐ and ss/dsDNA‐binding proteins were used to visualize ssDNA and total DNA in biofilms and planktonic cultures. Remarkably, mainly dsDNA was detected in biofilms of the ssDNA secreting strain. We conclude that the secreted ssDNA facilitates initial biofilm formation, but that the secreted ssDNA is not retained in mature biofilms.
Clustering, persistence and control of a pollinator brood disease: epidemiology ofAmerican foulbrood
Authors: Mill Aileen C. , Rushton Steven P , Shirley Mark D. F. , Smith Graham C. , Mason Phil , Brown Mike A. , Budge Giles E.
Published: October 2013

American foulbrood (AFB), caused byPaenibacillus larvae, is the most damaging bacterial brood disease of the honeybee (Apis mellifera), causing colony deaths on all continents where honeybees are managed.AFBhas been a persistent problem in theUKfor over 70 years, with a fluctuating number of cases discovered annually. Once diseased colonies are identified, they are destroyed to reduce pathogen spread. We investigated the pattern ofAFBcases recorded over the period 1994 to 2012 using spatial‐statistical approaches, with a view to identifying the nature of spread acrossEngland andWales. Our results indicated thatAFBexhibits significant spatial aggregation at distances from 10 to 30 km, with aggregations lasting between 1 and 5 years. Kernel smoothing indicated areas of elevated relative risk in different years, and these were further detailed by spatial‐scan statistics. We identified disease clusters and successfully estimated their size, location and duration. The majority of clusters did not persist in all years, indicating that management measures may lead to localized extinction of the disease. Whilst less common, persistent clusters likely indicate potential endemic or exotic risk points. The application of robust epidemiological approaches to improve the control ofAFBis discussed.