bluuebunny/crossref_metadata_2025 huggingface dataset:
Simplification is Complicated: Property, Nature, and the Rivers of Law
Authors: Blomley Nicholas
Published: July 2008

A number of scholars have criticized the ways in which property law simplifies nature. Such reductive simplifications are seen as being reliant upon a claim to mastery and dominion that is belied by the essential complexity and dynamism of the natural world. Drawing from a close reading of a property-boundary dispute involving the historical movements of the Missouri River, I supplement this account by revealing the ways in which legal simplication is itself complicated: that is, both dependent on considerable amounts of practical work, and subject to breakdown, ambiguity, and contradiction. Rather than a singular river, made legible through the unfolding of a unitary legal logic, I reveal several conflicting ‘rivers’ produced through property law. I conclude by trying to make sense of property as a set of practices that serve to produce the ‘effect’ of property. These practices, while often messy and contradictory, are, nevertheless, significant in the installation of property as a powerful organizing device through which the social world is made meaningful.
The Politics of True Convenience or Inconvenient Truth: Struggles over How to Sustain Capitalism, Democracy, and Ecology in the 21st Century
Authors: Luke Timothy W
Published: July 2008

This critique of inherent flaws in today's growth-driven natural capitalism argues its key contradictions and basic conflicts can be typified by the cultural politics and political economy found in the environmental advocacy of Al Gore Jr, especially in his Nobel Prize winning activities on global climate change in works like An Inconvenient Truth. In such criticism he aims neither to dismiss the dangers of global climate change nor to derogate the findings of ongoing scientific research, like that done by the co-awardees of the 2007 Nobel Peace Prize with Al Gore, namely, the Intergovernmental Panel on Climate Change. Rather, it is meant to begin a more pointed reassessment of how today's global climate-change debates are too entwined in the reproduction of most existing power relations and global market exchange. At best, Gore's work seems essentially to ‘greenwash’ existing networks of corporate organization and expert technocracy with renewed institutional legitimacy that only rinses today's unsustainable economic status quo in the refreshing, but not fully cleansing, waters of sustainable development ideology. While there is a need for systemic reforms in economic production, government regulation, technological innovation, and social distribution to mitigate climate change, Gore's many engagements with big business, venture capital, and global media do not appear to offer such a radical transformation. Instead, his basic project of decarbonizing the commodity chain mainly would appear to be a new program for further economic development that might not even retard, much less fully reverse, current climate-change trends.
Pathways to Sustainability in the Forest? Misunderstood Dynamics and the Negotiation of Knowledge, Power, and Policy
Authors: Leach Melissa
Published: July 2008

This paper addresses the challenges of building pathways to Sustainability in the context of contested knowledge and power relations in environment and development. Drawing on two case studies concerning tropical forests in West Africa and the Caribbean, it explores clashes between the conceptions of social–ecological systems embedded in dominant scientific and policy practices, and the more dynamic, nonequilibrial perspectives that emerge from understandings of forest history and users' own experiences. Forest and conservation policy, I find, have persistently ignored these dynamics. Yet, as people and nature have ‘bitten back’, forest histories are revealed as mutually constituting interplays of ecological process, social practice, policy and intervention, and response. Policy makers often do not see this, and are thus surprised when their schemes fail. In this paper, I argue that alternative analytical approaches are needed that take seriously human-ecological dynamics, history, path dependency, and the ways in which different people frame or construct problems, linked with notions of Sustainability that respect diverse goals—including forest users’ own. This, in turn, suggests the need for alternative approaches to the governance of environment and development issues that are more adaptive, deliberative, and reflexive, and for politically engaged efforts to institute these in contexts where pervasive power–knowledge relations perpetuate less dynamic views.
Images and Imagination in 20th-Century Environmentalism: From the Sierras to the Poles
Authors: Cosgrove Denis
Published: July 2008

Recent claims that the environmentalist thinking and politics that dominated the last years of the past century were based on outmoded, ‘Modernist’ categories jibe with academic criticism of dualistic thinking about ‘culture’ and ‘nature’, and with attempts to acknowledge the roles of nonhuman agency in the coconstruction of social worlds. While acknowledging the salience of these arguments, the author claims that examination of pictorial images that have shaped and promoted modern environmentalism complicate them. Pictorial images are less prone to dualistic interpretation than scientific and theoretical argument, and the affective responses they generate are complex. An examination of iconic images of key 20th-century environmental crises—wilderness preservation, soil erosion, urban sprawl, nuclear testing, and global environmental change—reveals both continuities in image making and presentation, and the evolving roles of physical nature itself in shaping their composition and meanings. Globalization of environmental concerns and images has shifted nature's icons from landscape towards living species, and from a temperate to a tropical and polar geography.
Has ‘Geography’ Always Been Modern?: Choros, (Non)Representation, Performance, and the Landscape
Authors: Olwig Kenneth R
Published: July 2008

The geographical subdiscipline of chorography, as described by Ptolemy and as interpreted in the Renaissance, played an important philosophical and practical role in the development of landscape as a form of spatial representation. This applies both to representation in the form of pictures, as in landscape painting, and to representation through the medium of perspectival theater scenery. These pictorial and scenic forms represented a reconfiguration of Platonic binaries between celestial and terrestrial nature and between mind (intellect) and body (sense). This reconfiguration generated a characteristically ‘modern’ dichotomy between society and its natural surroundings as well as the qualitative and the quantitative. The root of chorography is choros (also spelled chora), which basically means ‘place’. Present-day philosophical explorations of the meaning of choros suggest that the Plato-inspired Renaissance artists were essentially seeking to represent that which for Plato was actually unrepresentable. This interpretation is born out by an examination of the classical Greco-Roman chorography, as well as the expression of choros through the medium of classical Greek theater. This nonrepresentational notion of choros and chorography, as interpreted in present-day philosophy, has important implications for the contemporary concern with nonrepresentational geographies, landscape, and performance.
Power Relations: The Politics of Risk and Procedure in Nuclear Waste Governance
Authors: Chilvers Jason , Burgess Jacquelin
Published: July 2008

This paper develops a critical perspective on the ‘new’ governance of science and the environment which is increasingly evident in practical attempts to build more constructive relations between science and democracy through hybrid ‘analytic–deliberative’ processes. The focus is on recent institutional and participatory experiments in the governance of nuclear waste, specifically the work of the UK Committee on Radioactive Waste Management and the trialling of a novel participatory, multicriteria, options appraisal tool called Deliberative Mapping undertaken by the authors as part of this process. Drawing on these attempts to build relations and make connections between citizens, specialists, stakeholders and policy makers, radioactive wastes, and possible courses of action for their long-term management, the methodological performance of analytic–deliberative practices and the contextual influences that frame and govern them is evaluated. The paper demonstrates powerful framing effects operated at the level of specific participatory practices, procedural politics surrounding the design of ‘new’ governance institutions, and institutional behaviour linked to wider politics of environmental risk and energy futures which narrowed down and marginalised particular discourses, knowledges, meanings, and forms of expression. Unless these often tacit power relations are acknowledged, accounted for, and exposed by all involved, but especially vested interests, analytic–deliberative institutions may well undermine public trust, credibility, and legitimacy rather than promote these democratic virtues as is widely claimed.
From fresh to saline: a comparison of zooplankton and plant communities developing under a gradient of salinity with communities developing under constant salinity levels
Authors: Nielsen Daryl L. , Brock Margaret A. , Vogel Matthew , Petrie Rochelle
Published: July 2008

In Australia, many freshwater wetlands are becoming saline. Knowing which elements of a biotic community will persist as wetlands turn saline is relevant to their future management. We simulated gradual and sudden increases in salinity in outdoor mesocosms to test the hypotheses that: (1) aquatic plant and zooplankton communities exposed to a gradient of increasing salinity over time would initially resemble freshwater communities, but as the salinity increased they would resemble communities found in more saline systems; and (2) that a gradual change in salinity over 6 months influences zooplankton and plant communities in the same way as a sudden salinity change. Below 1000 mg L–1, as salinity increased gradually, communities rich in species and numbers of individuals resembled freshwater communities. However, as the salinity exceeded 1000 mg L–1, taxa were progressively lost and communities became less diverse. When salinities exceeded 3000 mg L–1 the diversity decreased rapidly and few taxa remained at 5000 mg L–1. Both sudden and gradual increases in salinity induced similar decreases in diversity. We predict that as natural wetlands become more saline, few freshwater biota will survive once the salinity exceeds 5000 mg L–1. In the long term, such salinised wetlands would need to be recolonised by salt-tolerant taxa for a functional wetland to persist.
Looking through glassfish: marine genetic structure in an estuarine species
Authors: Mills Courtenay E. , Hadwen Wade L. , Hughes Jane M.
Published: July 2008

Through the use of mitochondrial DNA (ATP8 gene), the prediction of intermediate genetic structuring was investigated in two species of estuarine glassfish (Ambassis marianus and Ambassis jacksoniensis) (Perciformes : Ambassidae) to determine the possibility of a generalised ‘estuarine’ genetic structure. Individuals were collected from estuaries in eastern Australia between Tin Can Bay (Queensland) in the north and Kempsey (New South Wales) in the south. Analysis of the haplotype frequencies found in this region suggested panmictic populations with star-like phylogenies with extremely high levels of genetic diversity, but with no correlation between geographic distance and genetic distance. Non-significant FST and ΦST suggested extensive dispersal among estuaries. However, Tajima’s D and Fu’s FS values suggest ‘mutation–genetic drift equilibrium’ has not been reached, and that population expansions occurring 262 000 (A. marianus) and 300 000 (A. jacksoniensis) years ago may obscure any phylogeographic structuring or isolation by distance. The finding of panmixia was contrary to the prediction of genetic structuring intermediate between that of marine fish (shallowly structured) and freshwater fish (highly structured), suggesting high dispersal capabilities in these species.
Anthropogenic influence on an urban colony of the little penguin Eudyptula minor
Authors: Giling Darren , Reina Richard D. , Hogg Zoe
Published: July 2008

Native animals exploit resources in cities and inhabit anthropogenic structures worldwide. One example of this is the little penguin, Eudyptula minor, population nesting between boulders on the St Kilda breakwater in Melbourne. This population is attracted by safe hiding places, a lack of predators and the presence of prey. However, living close to urbanisation poses many threats to the colony, including boating, lighting, noise and human visitation. We investigated the effects of human disturbance by comparing the number of penguins and breeding sites in the publicly accessible region with those in the restricted region of the breakwater. Penguins and nest sites were not equally distributed along the breakwater, with the mean number of birds and nest sites present per 20-m section in the restricted region significantly greater (typically double) than the number in the publicly accessible region. Although the penguins show a clear preference to nest in the restricted region of the breakwater, their continued presence in the publicly accessible region when nest sites are not limiting indicates that human disturbance is not incompatible with some nesting activity. In a global context these results illustrate some of the benefits and costs to animals that use anthropogenically altered habitats and urban environments.
A centralized gene-based HIV-1 vaccine elicits broad cross-clade cellular immune responses in rhesus monkeys
Authors: Santra Sampa , Korber Bette T. , Muldoon Mark , Barouch Dan H. , Nabel Gary J. , Gao Feng , Hahn Beatrice H. , Haynes Barton F. , Letvin Norman L.
Published: July 2008

One of the major challenges that must be met in developing an HIV-1 vaccine is devising a strategy to generate cellular immunity with sufficient breadth to deal with the extraordinary genetic diversity of the virus. Amino acids in the envelopes of viruses from the same clade can differ by >15%, and those from different clades can differ by >30%. It has been proposed that creating immunogens using centralized HIV-1 gene sequences might provide a practical solution to this problem. Such centralized genes can be generated by employing a number of different strategies: consensus, ancestral, or center of tree sequences. These computer-generated sequences are a shorter genetic distance from any two contemporary virus sequences than those contemporary sequences are from each other. The present study was initiated to evaluate the breadth of cellular immunity generated through immunization of rhesus monkeys with vaccine constructs expressing either an HIV-1 global consensus envelope sequence (CON-S) or a single patient isolate clade B envelope sequence (clade B). We show that vaccine immunogens expressing the single centralized gene CON-S generated cellular immune responses with significantly increased breadth compared with immunogens expressing a wild-type virus gene. In fact, CON-S immunogens elicited cellular immune responses to 3- to 4-fold more discrete epitopes of the envelope proteins from clades A, C, and G than did clade B immunogens. These findings suggest that immunization with centralized genes is a promising vaccine strategy for developing a global vaccine for HIV-1 as well as vaccines for other genetically diverse viruses.
Rapid encoding of new information alters the profile of plasticity-related mRNA transcripts in the hippocampal CA3 region
Authors: Haberman Rebecca P. , Lee Hongjoo J. , Colantuoni Carlo , Koh Ming Teng , Gallagher Michela
Published: July 2008

A theoretical framework for the function of the medial temporal lobe system in memory defines differential contributions of the hippocampal subregions with regard to pattern recognition retrieval processes and encoding of new information. To investigate molecular programs of relevance, we designed a spatial learning protocol to engage a pattern separation function to encode new information. After background training, two groups of animals experienced the same new training in a novel environment; however, only one group was provided spatial information and demonstrated spatial memory in a retention test. Global transcriptional analysis of the microdissected subregions of the hippocampus exposed a CA3 pattern that was sufficient to clearly segregate spatial learning animals from control. Individual gene and functional group analysis anchored these results to previous work in neural plasticity. From a multitude of expression changes, increases in
camk2a
,
rasgrp1
, and
nlgn1
were confirmed by
in situ
hybridization. Furthermore, siRNA inhibition of
nlgn1
within the CA3 subregion impaired spatial memory performance, pointing to mechanisms of synaptic remodeling as a basis for rapid encoding of new information in long-term memory.
Melanin-concentrating hormone as a mediator of intestinal inflammation
Authors: Kokkotou Efi , Moss Alan C. , Torres Daniel , Karagiannides Iordanes , Cheifetz Adam , Liu Sumei , O'Brien Michael , Maratos-Flier Eleftheria , Pothoulakis Charalabos
Published: July 2008

Melanin-concentrating hormone (MCH) is expressed primarily in the hypothalamus and has a positive impact on feeding behavior and energy balance. Although MCH is expressed in the gastrointestinal tract, its role in this system remains elusive. We demonstrate that, compared to wild type, mice genetically deficient in MCH had substantially reduced local inflammatory responses in a mouse model of experimental colitis induced by intracolonic administration of 2,4,6 trinitrobenzene sulfonic acid (TNBS). Likewise, mice receiving treatments with an anti-MCH antibody, either prophylactically or after the establishment of colitis, developed attenuated TNBS-associated colonic inflammation and survived longer. Consistent with a potential role of MCH in intestinal pathology, we detected increased colonic expression of MCH and its receptor in patients with inflammatory bowel disease. Moreover, we found that human colonic epithelial cells express functional MCH receptors, the activation of which induces IL-8 expression. Taken together, these results clearly implicate MCH in inflammatory processes in the intestine and perhaps elsewhere.
RIG-I plays a critical role in negatively regulating granulocytic proliferation
Authors: Zhang Nan-Nan , Shen Shu-Hong , Jiang Lin-Jia , Zhang Wu , Zhang Hong-Xin , Sun Yue-Ping , Li Xian-Yang , Huang Qiu-Hua , Ge Bao-Xue , Chen Sai-Juan , Wang Zhu-Gang , Chen Zhu , Zhu Jiang
Published: July 2008

RIG-I has been implicated in innate immunity by sensing intracellular viral RNAs and inducing type I IFN production. However, we have found a significant RIG-I induction in a biological setting without active viral infection—namely, during RA-induced terminal granulocytic differentiation of acute myeloid leukemias. Here, we present evidence that a significant Rig-I induction also occurs during normal myelopoiesis and that the disruption of the
Rig-I
gene in mice leads to the development of a progressive myeloproliferative disorder. The initiation of progressive myeloproliferative disorder is mainly due to an intrinsic defect of
Rig-I
−/−
myeloid cells, which are characterized by a reduced expression of IFN consensus sequence binding protein, a major regulator of myeloid differentiation. Thus, our study reveals a critical regulatory role of Rig-I in modulating the generation and differentiation of granulocytes.
p120 and Kaiso RegulateHelicobacter pylori-induced Expression of Matrix Metalloproteinase-7
Authors: Ogden Seth R. , Wroblewski Lydia E. , Weydig Christiane , Romero-Gallo Judith , O'Brien Daniel P. , Israel Dawn A. , Krishna Uma S. , Fingleton Barbara , Reynolds Albert B. , Wessler Silja , Peek Richard M.
Published: July 2008

Helicobacter pylori is the strongest known risk factor for gastric adenocarcinoma, yet only a fraction of infected persons develop cancer. One H. pylori constituent that augments disease risk is the cytotoxin-associated gene (cag) pathogenicity island, which encodes a secretion system that translocates bacterial effector molecules into host cells. Matrix metalloproteinase (MMP)-7, a member of a family of enzymes with tumor-initiating properties, is overexpressed in premalignant and malignant gastric lesions, and H. pylori cag+strains selectively increase MMP-7 protein levels in gastric epithelial cells in vitro and in vivo. We now report that H. pylori-mediated mmp-7 induction is transcriptionally regulated via aberrant activation of p120-catenin (p120), a component of adherens junctions. H. pylori increases mmp-7 mRNA levels in a cag- and p120-dependent manner and induces translocation of p120 to the nucleus in vitro and in a novel ex vivo gastric gland culture system. Nuclear translocation of p120 in response to H. pylori relieves Kaiso-mediated transcriptional repression of mmp-7, which is implicated in tumorigenesis. These results indicate that selective and coordinated induction of mmp-7 expression by H. pylori cag+isolates may explain in part the augmentation in gastric cancer risk associated with these strains.
Assembly of a Fab1 Phosphoinositide Kinase Signaling Complex Requires the Fig4 Phosphoinositide Phosphatase
Authors: Botelho Roberto J. , Efe Jem A. , Teis David , Emr Scott D.
Published: July 2008

Phosphatidylinositol-3,5-bisphosphate [PtdIns(3,5)P2] regulates several vacuolar functions, including acidification, morphology, and membrane traffic. The lipid kinase Fab1 converts phosphatidylinositol-3-phosphate [PtdIns(3)P] to PtdIns(3,5)P2. PtdIns(3,5)P2levels are controlled by the adaptor-like protein Vac14 and the Fig4 PtdIns(3,5)P2-specific 5-phosphatase. Interestingly, Vac14 and Fig4 serve a dual function: they are both implicated in the synthesis and turnover of PtdIns(3,5)P2by an unknown mechanism. We now show that Fab1, through its chaperonin-like domain, binds to Vac14 and Fig4 and forms a vacuole-associated signaling complex. The Fab1 complex is tethered to the vacuole via an interaction between the FYVE domain in Fab1 and PtdIns(3)P on the vacuole. Moreover, Vac14 and Fig4 bind to each other directly and are mutually dependent for interaction with the Fab1 kinase. Our observations identify a protein complex that incorporates the antagonizing Fab1 lipid kinase and Fig4 lipid phosphatase into a common functional unit. We propose a model explaining the dual roles of Vac14 and Fig4 in the synthesis and turnover of PtdIns(3,5)P2.
Glucocorticoid Signaling Defines a Novel Commitment State during AdipogenesisIn Vitro
Authors: Pantoja Carlos , Huff Jason T. , Yamamoto Keith R.
Published: July 2008

Differentiation of 3T3-L1 preadipocytes can be induced by a 2-d treatment with a factor “cocktail” (DIM) containing the synthetic glucocorticoid dexamethasone (dex), insulin, the phosphodiesterase inhibitor methylisobutylxanthine (IBMX) and fetal bovine serum (FBS). We temporally uncoupled the activities of the four DIM components and found that treatment with dex for 48 h followed by IBMX treatment for 48 h was sufficient for adipogenesis, whereas treatment with IBMX followed by dex failed to induce significant differentiation. Similar results were obtained with C3H10T1/2 and primary mesenchymal stem cells. The 3T3-L1 adipocytes differentiated by sequential treatment with dex and IBMX displayed insulin sensitivity equivalent to DIM adipocytes, but had lower sensitivity to ISO-stimulated lipolysis and reduced triglyceride content. The nondifferentiating IBMX–then-dex treatment produced transient expression of adipogenic transcriptional regulatory factors C/EBPβ and C/EBPδ, and little induction of terminal differentiation factors C/EBPα and PPARγ. Moreover, the adipogenesis inhibitor preadipocyte factor-1 (Pref-1) was repressed by DIM or by dex-then-IBMX, but not by IBMX-then-dex treatment. We conclude that glucocorticoids drive preadipocytes to a novel intermediate cellular state, the dex-primed preadipocyte, during adipogenesis in cell culture, and that Pref-1 repression may be a cell fate determinant in preadipocytes.
The Dynamics of Mammalian P Body Transport, Assembly, and Disassembly In Vivo
Authors: Aizer Adva , Brody Yehuda , Ler Lian Wee , Sonenberg Nahum , Singer Robert H. , Shav-Tal Yaron
Published: July 2008

Exported mRNAs are targeted for translation or can undergo degradation by several decay mechanisms. The 5′→3′ degradation machinery localizes to cytoplasmic P bodies (PBs). We followed the dynamic properties of PBs in vivo and investigated the mechanism by which PBs scan the cytoplasm. Using proteins of the decapping machinery, we asked whether PBs actively scan the cytoplasm or whether a diffusion-based mechanism is sufficient. Live-cell imaging showed that PBs were anchored mainly to microtubules. Quantitative single-particle tracking demonstrated that most PBs exhibited spatially confined motion dependent on microtubule motion, whereas stationary PB pairs were identified at the centrosome. Some PBs translocated in long-range movements on microtubules. PB mobility was compared with mitochondria, endoplasmic reticulum, peroxisomes, SMN bodies, and stress granules, and diffusion coefficients were calculated. Disruption of the microtubule network caused a significant reduction in PB mobility together with an induction of PB assembly. However, FRAP measurements showed that the dynamic flux of assembled PB components was not affected by such treatments. FRAP analysis showed that the decapping enzyme Dcp2 is a nondynamic PB core protein, whereas Dcp1 proteins continuously exchanged with the cytoplasm. This study reveals the mechanism of PB transport, and it demonstrates how PB assembly and disassembly integrate with the presence of an intact cytoskeleton.
Paracingulin Regulates the Activity of Rac1 and RhoA GTPases by Recruiting Tiam1 and GEF-H1 to Epithelial Junctions
Authors: Guillemot Laurent , Paschoud Serge , Jond Lionel , Foglia Andrea , Citi Sandra
Published: July 2008

Small GTPases control key cellular events, including formation of cell–cell junctions and gene expression, and are regulated by activating and inhibiting factors. Here, we characterize the junctional protein paracingulin as a novel regulator of the activity of two small GTPases, Rac1 and RhoA, through the functional interaction with their respective activators, Tiam1 and GEF-H1. In confluent epithelial monolayers, paracingulin depletion leads to increased RhoA activity and increased expression of mRNA for the tight junction protein claudin-2. During tight junction assembly by the calcium-switch, Rac1 shows two transient peaks of activity, at earlier (10–20 min) and later (3–8 h) time points. Paracingulin depletion reduces such peaks of Rac1 activation in a Tiam1-dependent manner, resulting in a delay in junction formation. Paracingulin physically interacts with GEF-H1 and Tiam1 in vivo and in vitro, and it is required for their efficient recruitment to junctions, based on immunofluorescence and biochemical experiments. Our results provide the first description of a junctional protein that interacts with GEFs for both Rac1 and RhoA, and identify a novel molecular mechanism whereby Rac1 is activated during junction formation.
Double cavity flow past a wedge
Authors: Antipov Y.A , Silvestrov V.V
Published: July 2008

A mathematical model of supercavitating flow past a wedge with sides of arbitrary length is proposed. The flow branches at a point on the lower side of the wedge. At the vertex of the wedge and at the ends of the wedge, the flow breaks away forming a nose bubble and a trailing cavity. The closure mechanism is described by the Tulin single-spiral-vortex model. The flow domain is mapped into a parametric plane cut along a unit segment. The conformal mapping function is reconstructed through the exact solution of two Riemann–Hilbert problems on a genus-zero Riemann surface. To complete the solution, one needs to determine five real parameters from a certain system of transcendental equations. Numerical results are presented for the case when a wedge can rotate about the vertex in the flow domain. In this case, the flow branches at the vertex and the number of the parameters to be determined is 3.
Matchgates and classical simulation of quantum circuits
Authors: Jozsa Richard , Miyake Akimasa
Published: July 2008

LetG(A, B) denote the two-qubit gate that acts as the one-qubitSU(2) gatesAandBin the even and odd parity subspaces, respectively, of two qubits. Using a Clifford algebra formalism, we show that arbitrary uniform families of circuits of these gates, restricted to act only on nearest neighbour (n.n.) qubit lines, can be classically efficiently simulated. This reproduces a result originally proved by Valiant using his matchgate formalism, and subsequently related by others to free fermionic physics. We further show that if the n.n. condition is slightly relaxed, to allow the same gates to act only on n.n. and next n.n. qubit lines, then the resulting circuits can efficiently perform universal quantum computation. From this point of view, the gap between efficient classical and quantum computational power is bridged by a very modest use of a seemingly innocuous resource (qubit swapping). We also extend the simulation result above in various ways. In particular, by exploiting properties of Clifford operations in conjunction with the Jordan–Wigner representation of a Clifford algebra, we show how one may generalize the simulation result above to provide further classes of classically efficiently simulatable quantum circuits, which we call Gaussian quantum circuits.
When does ecosystem engineering cause invasion and species replacement?
Authors: Gonzalez Andrew , Lambert Amaury , Ricciardi Anthony
Published: July 2008

Introduced exotic species can dominate communities and replace native species that should be better adapted to their local environment, a paradox that is usually explained by the absence of natural enemies and by habitat alteration resulting from anthropogenic disturbance. Additionally, introduced species can enhance their invasion success and impact on native species by modifying selection pressures in their new environment through ecosystem engineering. We analyse a simple dynamic model of indirect competition for habitat between a non‐engineering resident species and an engineering exotic species. The conditions for invasion and competitive exclusion of the resident by the exotic species and the range of dynamic outcomes suggested by the model are determined by the form of density dependence. We give simple criteria for the success of the invading species on dimensionless quantities involving rates of ecosystem engineering and of habitat degradation. The model's predictions offer an additional explanation for a range of invasion dynamics reported in the literature, including lag times between introduction and establishment. One intriguing result is that a series of failed invasions may successively reduce environmental resistance to subsequent invasion, through a cumulative effect of habitat transformation. More work is needed to determine the frequency and conditions in which engineering is required for successful establishment, and whether highly‐successful (or high‐impact) invaders are more likely to possess ecosystem engineering traits.
Reconciling neutral community models and environmental filtering: theory and an empirical test
Authors: Jabot Franck , Etienne Rampal S. , Chave Jérôme
Published: July 2008

It is widely believed that the neutral theory of biodiversity cannot be used for parameter inference if the assumption of neutrality is not met. The goal of this work is to extend this neutral framework to quantify the intensity of recruitment limitation (limited dispersal plus environmental filtering) in natural species assemblages. We model several local communities as part of a larger metacommunity, and we assume that neutrality holds in each local community, but not in the metacommunity. The immigration rate m does not only reflect dispersal limitation into a given local community, but also the intensity of environmental filtering. We develop a novel statistical method to infer the immigration parameter m in each local community. Using simulated datasets, we show that m indeed depends on both dispersal limitation and on the intensity of environmental filtering. We then apply this method to a network of tropical tree plots in central Panama. Inferred recruitment rates m were positively correlated with the fraction of trees dispersed by mammals, and with annual rainfall, possibly due to a weaker environmental filtering as rainfall increases. Finally, m, as estimated from trees greater than 1 cm trunk diameter, were significantly larger than an estimation based on trees greater than 10 cm trunk diameter. This suggests a cumulative effect of environmental filtering upon trees throughout their ontogeny.
The effects of the polymorphism in exon 3 of the FAS gene on the death of chicken embryos during the incubation period
Authors: Wu J. J. , Li W. M. , Zhao R. X. , Fang J. , Wang C. , Peng X. L. , Li X. , Xiong J. J. , Yang L. G. , Zhang S. J.
Published: July 2008

To investigate the effect of a factor‐associated suicide (FAS) gene polymorphism on the death of chicken embryos, we genotyped 190 dead embryos and 69 normally developing embryos from 7200 hatching Short‐Leg Yellow Chicken eggs, as well as 119 dead embryos and 69 normally developing embryos from 4650 hatching Yellow B Chicken eggs. The results showed that there were significant (P < 0.05) genotypic differences between dead and normally developing embryos for this FAS gene polymorphism, a SNP in exon 3 (NC_006093.2:g.6514A>C, rs15793179). Logistic regression revealed that Short‐Leg Yellow Chicken embryos with genotype g.6514CC had a significantly (P < 0.01) higher risk of death than those with genotype g.6514AC. This polymorphism has the potential to be an effective tool when used in conjunction with traditional selection methods.
A comparative study of two methods for attaining constant alcohol levels
Authors: Zoethout Remco W. M. , Van Gerven Joop M. A. , Dumont Glenn J. H. , Paltansing Sunita , Van Burgel Nathalie D. , Van Der Linden Monique , Dahan Albert , Cohen Adam F. , Schoemaker Rik C.
Published: July 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• In determining the effects of alcohol or assessing alcohol–drug interactions, it is helpful if the alcohol plasma concentration can be maintained at reasonably stable levels.

• To achieve pseudo‐steady state alcohol concentrations various methods are used.

• In this study two different methods were optimized and compared in the search for an accurate method to maintain constant alcohol levels for a prolonged period of time.

WHAT THIS STUDY ADDS

• Although it seems clear that alcohol clamping improves the stability of alcohol levels, it has not yet been established how this compares with other procedures, such as two‐step prekinetic methods.

• The adapted clamping paradigm was superior to the prekinetic method in this study.

• The novel clamping procedure is an accurate, user‐friendly method, with low variability, able to maintain constant alcohol levels for hours.

• Moreover, the procedure gave an opportunity to perform intensive pharmacodynamic or functional assessments during the execution of the clamp, which could be of great value for future studies of alcohol.

AIMS

Alcohol effects or drug–alcohol interactions are preferably studied at constant blood levels. To achieve pseudo‐steady state levels, various methods are used, which usually produce adequate averages but variable individual concentration profiles. The aim was to compare two modes of alcohol administration: a ‘two‐step prekinetic procedure’ and a ‘clamping method’.

METHODS

The two‐step prekinetic procedure started with determination of individual pharmacokinetic (PK) parameters, during a prestudy occasion. Individual infusion regimens were calculated afterwards, based on a pseudo‐steady state breath alcohol concentration (BrAC) of 0.65 g l−1 and applied on a separate occasion. For the clamping procedure, a spreadsheet‐based paradigm was developed using BrAC‐guided adjustments of infusion rates, to maintain stable BrAC levels of 0.6 g l−1.

RESULTS

The mean BrAC during clamping [0.61 g l−1, 95% confidence interval (CI) 0.58, 0.63] did not differ from its intended level of 0.6 g l−1 (1.0% on average). In contrast, the mean BrAC during the prekinetic procedure was significantly lower than the 0.65 g l−1 set‐point (0.59 g l−1, 95% CI 0.54, 0.63) and deviated from this target by 9.7% on average. The clamping method also showed less variation between subjects [coefficient of variation (CV) 6.2%] compared with the prekinetic procedure (CV 14.6%).

CONCLUSIONS

Although the two methods differ considerably in their approach, clamping of BrAC resulted in more accurate alcohol levels than infusion based on PK modelling and does not require an extra prestudy occasion. The novel alcohol clamping paradigm can be of value in future studies of alcohol interactions or the pharmacodynamics of acute alcohol administration.
Impact of adherence to statins on chronic heart failure in primary prevention
Authors: Perreault Sylvie , Dragomir Alice , Blais Lucie , Bérard Anick , Lalonde Lyne , White Michel
Published: July 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• The effects of statins may be beneficial to patients with chronic heart failure.

• However, one question that has not yet been answered and that may clarify the role of statins in chronic heart failure (CHF) is whether statins prevent the development of CHF in patients with a low risk of cardiovascular disease (CVD)?

WHAT THIS PAPER ADDS

• The study results demonstrate that, in primary prevention, adherence to statins has a positive impact on CHF.

• This study provides evidence of the potential role of statins in CHF.

AIMS

Statins are effective in the prevention of an atherosclerotic event, e.g. coronary artery disease and cerebrovascular disease. Patients at high risk of cardiovascular disease (CVD), such as chronic heart failure (CHF), might benefit from the effects of statin therapy. However, one question that has not yet been answered and that may clarify the role of statins in CHF is whether statins prevent the development of CHF in patients with a low risk of CVD. Our aim was to evaluate the impact of adherence to statins on the incidence of CHF.

METHODS

A cohort of 111 481 patients was reconstructed using the Régie de l'Assurance Maladie du Québec databases. Patients were eligible if they were between 45 and 85 years old, without CVD, and newly treated with statins between 1999 and 2004. A nested case–control design was used to study CHF. Every case of CHF was matched for age and duration of follow‐up in up to 15 randomly selected controls. The adherence level was measured by calculating the medication possession ratio. Rate ratios (RR) of CHF were estimated by conditional logistic regression adjusting for several covariables.

RESULTS

The mean patient age was 63 years, 49% had hypertension, 21% had diabetes and 41% were male. A high level of adherence to statins was associated with a reduction of CHF (RR 0.81; 0.71, 0.91). The risks associated with CHF were the development of CVD during follow‐up, being a social‐aid recipient, and suffering from hypertension, diabetes mellitus, or having a higher chronic disease score.

CONCLUSION

Our study indicates that better adherence to statins is associated with a reduced risk of CHF.
Predation by an exotic lizard,Anolis sagrei, alters the ant community structure in betelnut palm plantations in southern Taiwan
Authors: HUANG SHAO‐CHANG , NORVAL GERRUT , TSO I‐MIN
Published: July 2008

Abstract1. Predators can affect prey directly by reducing prey abundance and indirectly by altering behavioural patterns of prey. From previous studies, there is little evidence that ant community structure is affected by vertebrate predation.

2. Researchers tend to consider the interactions between vertebrate predators and ants to be weak. The present study examined the impact of the exotic invasive lizard,Anolis sagrei, on the ant community structure by manipulating the density of lizards within enclosures. The natural density ofA. sagreiin the field was surveyed and used as the stocking density rate in the lizard‐present sub‐enclosures.

3. Before the lizard density was manipulated, there was no difference in the ant diversity between sub‐enclosures. After the lizard density manipulation, the ant diversity in sub‐enclosures withA. sagreipresent was significantly different from that of enclosures where the lizards were absent, although the overall ant abundance did not differ significantly.

4. The ant diversity difference was generated by a significant reduction of the ant speciesPheidole fervensin sub‐enclosures withA. sagreipresent. Such an abundance change might be the result of direct predation by the lizards, or it might be generated by a foraging site shift by this ant.

5. The results of this study thus demonstrated that the invasion of an exotic vertebrate can significantly alter the community structure of ants, perhaps through the combined direct and indirect effects of lizards on ants.
Leaf mining in the Myrtaceae
Authors: SINCLAIR ROBYN JEAN , HUGHES LESLEY
Published: July 2008

Abstract 1. Leaf mining insects feed within plant tissue and thus have close physical associations with their host plants. Little is known about the evolution of relationships between leaf miners and their host species.

2. The prevalence of leaf mining was examined in relation to the phylogeny of a dominant family of Australian plants, the Myrtaceae. Sixty‐eight species from the 10 major phylogenetic groups within the family were sampled in south‐eastern Australia.

3. Fifty‐seven per cent of the plant species examined were found to be mined. Several leaf traits were compared between mined and unmined plant species to investigate the potential role of both physical and nutritional characteristics in determining host‐plant susceptibility to these herbivores.

4. The physical leaf traits measured were leaf area, specific leaf area (SLA), lamina thickness, toughness, and amount of fibre (percentage hemicellulose). The nutritional traits were water content, and concentrations of carbon, nitrogen, total phenols and condensed tannins. Principal component analysis showed mined plant species differed from unmined in terms of several leaf traits.

5. In a post hoc regression weighted for phylogeny, leaf miner presence was significantly positively correlated with plant species having thinner laminas and higher phenol concentrations, and was positively correlated with marginal significance to SLA and water content.
Variation in food availability influences prey‐capture method in antlion larvae
Authors: ELIMELECH EFRAT , PINSHOW BERRY
Published: July 2008

Abstract 1. Larvae of a Myrmecaelurus sp. are unique among antlions because they have two prey‐capture methods; they either ambush prey at the surface, or dig pit traps that prey fall in to. It was hypothesised that larvae will use the capture method that maximises their net rate of energy gain, which will be influenced by food availability (encounter rate) and by past energy inputs (body condition).

2. Costs were estimated by measuring resting and activity metabolic rates and determining the duration of pit maintenance at various encounter rates with ants that served as prey. Benefits were estimated from the energy gained per ant captured at different encounter rates.

3. Net energy gained was higher with a pit than without one, and was influenced more by the differences in prey capture rate between the two capture methods, and less by the differences in energy costs associated with each method. The proportion of larvae that constructed pits was higher when they were in intermediate body condition than when in good or in poor body condition.

4. Thus, the use of one capture method or the other depends on a combination of the influences of past net energy gain and the antlion’s most recent change in encounter rate with prey. Ambushing without a pit may serve as a default when physiological constraints limit the larvae’s ability to invest in pit construction and maintenance, or when larvae are sated, and saving the energy of pit construction and maintenance is worthwhile.
Negative interactions between chemical resistance and predators affect fitness in soybeans
Authors: BARTLETT RYAN
Published: July 2008

Abstract 1. Plants may benefit from both chemical resistance traits and the presence of predators of herbivores. In past studies, the interaction between resistance and predators varies from complementary to antagonistic among different systems. However, this interaction has primarily been quantified by effects on predator abundance or vigor, not effects on plant fitness.

2. In this study, the combined effects of chemical resistance and predators on plant fitness were examined using soybeans (Glycine max), herbivorous Mexican bean beetles (Epilachna varivestis), and predaceous spined soldier bugs (Podisus maculiventris). Mexican bean beetles were reared in field cages in the presence or absence of spined soldier bugs on soybeans with or without strong constitutive chemical resistance.

3. Spined soldier bugs were more likely to feed on Mexican bean beetles that fed on susceptible than on resistant plants.

4. Susceptible plants with predators produced significantly more seeds than those without predators, while resistant plants did not produce significantly different numbers of seeds based on the presence or absence of predators.

5. Selection for the production of some types of chemical resistance in plants would thus be expected to be stronger with lower predation rates.

6. These results also suggest predator introductions would be more effective on plants without a strong constitutive chemical resistance to herbivores.
The relative importance of dispersal and local processes in structuring phytoplankton communities in a set of highly interconnected ponds
Authors: VANORMELINGEN PIETER , COTTENIE KARL , MICHELS ERIK , MUYLAERT KOENRAAD , VYVERMAN WIM , DE MEESTER LUC
Published: July 2008

1. The recognition that both local and regional processes act together in shaping local communities makes determining their relative roles in natural communities central to understanding patterns in community structure.

2. We investigated the relative influence of these processes on the phytoplankton communities of a highly interconnected pond system. We sampled the phytoplankton communities of 28 ponds concurrently with 20 local environmental variables.

3. We found that phytoplankton community variation, in terms of both phytoplankton community composition (PCC) and diversity, was only significantly explained by local environmental variables. These were mainly associated with the contrasting clear‐water and turbid ecological states of the shallow ponds studied. Clear‐water conditions favoured only a few taxa, resulting in a significantly lower taxon diversity and richness under these conditions.

4. The failure to explain variation in PCC by a dispersal model based on the water flow between ponds points at very effective species sorting. This is attributed to the high population turn‐over rates and sensitivity to environmental conditions of phytoplankton communities. Some evidence was found, however, that dispersal influences local communities through mass effects between neighbouring ponds.

5. Overall, our results emphasize both the strong selection pressure that components of the food web exert on phytoplankton communities and the high potential of these communities to respond to such environmental change, thereby effectively opposing the homogenizing effects of continuous dispersal.