bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational models and empirical constraints
Authors: Pylyshyn Zenon W.
Published: February 2010

It is argued that the traditional distinction between artificial intelligence and cognitive simulation amounts to little more than a difference in style of research - a different ordering in goal priorities and different methodological allegiances. Both enterprises are constrained by empirical considerations and both are directed at understanding classes of tasks that are defined by essentially psychological criteria. Because of the different ordering of priorities, however, they occasionally take somewhat different stands on such issues as the power/generality trade-off and on the relevance of the sort of data collected in experimental psychology laboratories.

Computational systems are more than a tool for checking the consistency and completeness of theoretical ideas. They are ways of empirically exploring the adequacy of methods and of discovering task demands. For psychologists, computational systems should be viewed as functional models quite independent of (and likely not reducible to) neurophysiological systems, and cast at a level of abstraction appropriate for capturing cognitive generalizations. As model objects, however, they do present a serious problem of interpretation and communication since the task of extracting the relevant theoretical principles from a large complex program may be formidable.

Methodologies for validating computer programs as cognitive models are briefly described. These may be classified as intermediate state, relative complexity, and component analysis methods. Compared with the constraints imposed by criteria such as sufficiency, breadth, and extendability, these experimentally based methods are relatively weak and may be most useful after some top-down progress is made in the understanding of methods sufficient for relevant tasks - such as may be forthcoming from artificial intelligence research.
Quotients of cluster categories
Authors: Jørgensen Peter
Published: February 2010

Higher cluster categories were recently introduced as a generalization of cluster categories. This paper shows that in Dynkin types A and D, half of all higher cluster categories can be obtained as quotients of cluster categories. The other half are quotients of 2-cluster categories, the ‘lowest’ type of higher cluster categories. Hence, in Dynkin types A and D, all higher cluster phenomena are implicit in cluster categories and 2-cluster categories. In contrast, the same is not true in Dynkin type E.
On travelling wavefronts of Nicholson's blowflies equation with diffusion
Authors: Lin Chi-Kun , Mei Ming
Published: February 2010

This paper is devoted to the study of Nicholson's blowflies equation with diffusion: a kind of time-delayed reaction diffusion. For any travelling wavefront with speed c > c* (c* is the minimum wave speed), we prove that the wavefront is time-asymptotically stable when the delay-time is sufficiently small, and the initial perturbation around the wavefront decays to zero exponentially in space as x → −∞, but it can be large in other locations. The result develops and improves the previous wave stability obtained by Mei et al. in 2004. The new approach developed in this paper is the comparison principle combined with the technical weighted-energy method. Numerical simulations are also carried out to confirm our theoretical results.
Matrix maps over planar near-rings
Authors: Ke Wen-Fong , Meyer Johan H. , Wendt Gerhard
Published: February 2010

Following a method by Meldrum and van der Walt, near-rings of matrix maps are defined for general near-rings, not necessarily with identity. The influence of one-sided identities is discussed. When the base near-ring is integral and planar, the near-ring of matrix maps is shown to be simple. Various types of primitivity of the near-ring of matrix maps are discussed when the base near-ring is planar but not integral. Finally, an open problem concerning bijective matrix maps is solved.
Stabilization and a class of functionals for linear parabolic control systems
Authors: Nambu Takao
Published: February 2010

In feedback stabilization studies, a control scheme is designed so that the ‘state’ of the system decays with a designated rate as t → ∞. Thus, any linear functional of the state also decays with at least the same decay rate. We study a class of linear parabolic systems, and show the existence of a feedback control scheme with a specific property such that some non-trivial linear functionals decay faster than the state. In constructing the control scheme, we also solve the new problem of an arbitrary allocation of the eigenvalues of some coefficient matrix which is subject to constraint, and give the necessary and sufficient condition in terms of controllability and observabililty assumptions. This is an essential extension of the celebrated 1967 theory of pole allocation by W. M. Wonham.
Hardy operators on weighted amalgams
Authors: Salvador Pedro Ortega , Torreblanca Consuelo Ramírez
Published: February 2010

We characterize the boundedness of the Hardy operator between weighted amalgams, a problem studied, but not completely solved, by C. Carton-Lebrun, H. P. Heinig and S. C. Hofmann. We also characterize the weighted weak-type inequalities for modified Hardy operators on amalgams.
Duality and compactness results in high-contrast homogenization of incompressible two-dimensional elasticity problems
Authors: Manceau David
Published: February 2010

Some of the proofs in the above paper are incomplete.

The pressure term in the incompressible elasticity equation needs to be considered and estimated in order to pass to the limit in the homogenization process. This will require Sections 2.2 and 3.2 to be rewritten.

A corrected version will be submitted in due course.
Effect of FSH and LH hormones on oocyte maturation of buffalo and gene expression analysis of their receptors and Cx43 in maturing oocytes
Authors: Pandey Alok , Gupta S.C. , Gupta Neelam
Published: February 2010

Follicle stimulating hormone (FSH) and luteinizing hormone (LH) are commonly added to maturation media to improve cumulus expansion known to be a predictor of oocyte maturation. Therefore, effects of various concentrations of FSH (1000 ng/ml), LH (1000 ng/ml) and FSH + LH (1000 ng/ml each) in comparison with control (without FSH + LH) cultured oocytes were investigated. FSH and LH (1000 ng/ml each) induced significantly more cumulus expansion and polar body numbers, as compared with control and treatments of 1000 ng/ml FSH and 1000 ng/ml LH alone. Expression of FSH receptor (r), LHr and Cx43 mRNAs was determined by real-time PCR in cumulus–oocyte complexes (COCs) and denuded oocytes at different maturation times. Expression of all three genes was higher in COCs compared with denuded oocytes, confirming the importance of cumulus cells in oocyte maturation. FSHr and connexin 43 (Cx43) mRNA abundance in both COCs and denuded oocytes was highest at 0–6 h of maturation and decreased subsequently. However, LHr mRNA abundance increased from 6 h up to 24 h of maturation. The study concluded that FSH, LH receptors and Cx43 gene expression regulation is an index related to oocyte maturation.
Deliberation and civic virtue: lessons from a citizen deliberation
experiment
Authors: Grönlund Kimmo , Setälä Maija , Herne Kaisa
Published: February 2010

This article analyzes whether democratic deliberation enhances ‘civic
virtues’ such as political knowledge, efficacy, trust, and preparedness for
political and other collective action. The empirical analysis is based on an
experiment held in November 2006 in Finland. The topic of this citizen
deliberation experiment was nuclear power. Two treatments were enforced;
half of the small groups made a decision through secret ballot, whereas the
other half formulated a common statement. Even though both treatments were
designed to be ‘deliberative’ with discussion rules and moderators, the
common statement procedure was expected to lead to more thorough
deliberation. Therefore, we anticipate more increase in civic virtues in the
common statement treatment. Based on the empirical analyses, this
expectation is partially confirmed. Most notably, the participants’
knowledge of energy-related issues increased more in the common statement
treatment, but also the increase of political trust and readiness for
collective action shows a similar pattern. Finally, deliberation did not
increase the participants’ overall preparedness to act politically, but did
not decrease it either.
Beyond American negativity: toward a general understanding of the
determinants of negative campaigning
Authors: Elmelund-Præstekær Christian
Published: February 2010

This article supplements and further develops the almost exclusively
American literature on the determinants of negative campaigning by analyzing
the tone of the Danish parties’ election campaigns. It concludes that
proximity to governmental power matters, as oppositional parties are more
negative than incumbents. This is comparable to the American experiences.
The prospect of electoral failure, however, does not affect the tone the
same way as poor poll standings do in the US. Moreover, it is suggested that
future studies of negativity might consider how different party
organizations affect the campaign tone; at least this study finds
indications that parties with large proportions of party identifiers are
slightly more negative than other parties. Finally, it is found that parties
campaign differently in different channels of communication; that is, they
are generally more negative in channels that allow direct interaction among
politicians. This finding poses the question whether some channels are
better empirical sources for studies of negativity than others, which is
addressed in the closing section of the article.
Pathophysiologie des Deliriums
Authors: Singler Katrin , Hafner Martina , Sieber Cornel
Published: February 2010

Während zur Epidemiologie und Ätiologie des Delirs zahlreiche Forschungsergebnisse vorliegen, ist das Wissen über die Pathophysiologie dieses Krankheitsbildes vergleichsweise gering. Die derzeit führende Hypothese postuliert einen Mangelzustand des cholinergen Systems. Auch spielen weitere Neurotransmitter wie Dopamin, Serotonin, Noradrenalin, Glutamat und Gamma-Amino-Butter-Säure sowie deren teils ungeklärte Interaktionen eine bedeutende Rolle. Zytokine wie Interleukin-1, Interleukin-2, Interleukin-6 und Tumor Nekrose Faktor-α können durch Veränderungen im Gleichgewicht der Neurotransmitter und Aktivierung des hypothalamisch-hypophysären Systems zur Delir-Entstehung beitragen. Der vorliegende Artikel fasst den gegenwärtigen Wissensstand pathophysiologischer Grundlagen in der Delir-Entstehung zusammen.
Shifts in microbial community structure along an ecological gradient of hypersaline soils and sediments
Authors: Hollister Emily B , Engledow Amanda S , Hammett Amy Jo M , Provin Tony L , Wilkinson Heather H , Gentry Terry J
Published: February 2010

Studies of hypersaline ecosystems often yield novel organisms and contribute to our understanding of extreme environments. Soils and sediments from La Sal del Rey, a previously uncharacterized, hypersaline lake located in southern Texas, USA, were surveyed to characterize the structure and diversity of their microbial communities. Samples were collected along a transect that spanned vegetated uplands, exposed lakebed sediments, and water-logged locations, capturing a wide range of environments and physical and chemical gradients. Community quantitative PCR (qPCR) was used in combination with tag-encoded pyrosequencing, 16S rRNA gene cloning, and Sanger sequencing to characterize the lake's soil and sediment microbial communities. Further, we used multivariate statistics to identify the relationships shared between sequence diversity and heterogeneity in the soil environment. The overall microbial communities were surprisingly diverse, harboring a wide variety of taxa, and sharing significant correlations with site water content, phosphorus and total organic carbon concentrations, and pH. Some individual populations, especially of Archaea, also correlated with sodium concentration and electrical conductivity salinity. Across the transect, Bacteria were numerically dominant relative to Archaea, and among them, three phyla—the Proteobacteria, Bacteroidetes, and Firmicutes—accounted for the majority of taxa detected. Although these taxa were detected with similar abundances to those described in other hypersaline ecosystems, the greater depth of sequencing achieved here resulted in the detection of taxa not described previously in hypersaline sediments. The results of this study provide new information regarding a previously uncharacterized ecosystem and show the value of high-throughput sequencing in the study of complex ecosystems.
Lack of Association Between PCK1 Polymorphisms and Obesity, Physical Activity, and Fitness in European Youth Heart Study (EYHS)
Authors: Vimaleswaran Karani S. , Franks Paul W. , Brage Soren , Grontved Anders , Wareham Nicholas J. , Ekelund Ulf , Loos Ruth J.F.
Published: February 2010

Phosphoenolpyruvate carboxykinase‐1 (PCK1) is the rate‐limiting enzyme in the hepatic gluconeogenic pathway. Studies have shown that overexpression of Pck1 in mice results in obesity‐related traits and higher levels of physical activity (PA). Therefore, our aims were to investigate whether common genetic variation in the PCK1 gene influences obesity‐related traits, PA, and fitness, and to examine whether PA and fitness attenuate the influence of the PCK1 polymorphisms on obesity in children. Analyses were undertaken on data from Danish and Estonian children (958 boys and 1,104 girls) from the European Youth Heart Study (EYHS), a school‐based, cross‐sectional study of children (mean ± s.d. age: 9.6 ± 0.4 years) and adolescents (15.5 ± 0.5 years). We genotyped eight polymorphisms that captured the common genetic variations in the PCK1 gene. The association between the PCK1 polymorphisms and BMI, waist circumference (WC), sum of four skinfolds, PA, and fitness was tested using an additive model adjusted for age, age‐group, gender, maturity, and country. Interactions were tested by including interaction terms in the model. None of the polymorphisms were significantly associated with BMI, WC, sum of four skinfolds, PA, and fitness, and also with the risk of being overweight or obese (P > 0.05). The interactions between the polymorphisms and age‐group, gender, PA, and fitness were not statistically significant. This is the first study to comprehensively examine the association of PCK1 polymorphisms with obesity, PA, and fitness. Despite strong evidence from animal studies, our study in the EYHS cohort failed to identify an association of PCK1 polymorphisms with obesity, PA, and fitness.
Independent Associations Between Cardiorespiratory Fitness and Abdominal Obesity With Metabolic Risk in Adolescents and Adults
Authors: Kuk Jennifer L. , Lee SoJung
Published: February 2010

Our objective was to examine the independent association between abdominal obesity (waist circumference (WC)) and cardiorespiratory fitness (CRF) with metabolic syndrome (MetS) in 2,197 adults (ages 20–49 years) and 3,223 adolescents (ages 12–19 years). Individuals were stratified by CRF and WC using sex‐ and age‐specific MetS criteria for adolescents and adults. Adolescents had a lower prevalence rate of MetS (5.4% vs. 12.8%) and high WC (15.5% vs. 35.7%), but a higher prevalence rate of low CRF (37.6% vs. 15.9%) than adults. As compared to adolescents and adults with low WC, those with a high WC (odds ratio (OR) = 5.5–16.5, P < 0.001) were more likely to have a clustering of MetS factors than those with low WC (OR = 1.2–3.8, P = 0.3 to <0.001), regardless of fitness level. Conversely, the beneficial effects of having moderate/high CRF on MetS were only observed in individuals with low WC, and not high WC. Thus, in conclusion, both high WC and low CRF are associated with increased odds of MetS in adolescents and adults. However, increased abdominal obesity is more strongly associated with MetS in adolescents and adults.
High Plasma Phospholipase A2 Activity, Inflammation Markers, and LDL Alterations in Obesity With or Without Type 2 Diabetes
Authors: Garces Fatima , López Flor , Niño Cladimar , Fernandez Anazita , Chacin Luis , Hurt‐Camejo Eva , Camejo Germán , Apitz‐Castro Rafael
Published: February 2010

Plasma phospholipases A2 (PLA2) hydrolyze phospholipids of circulating lipoproteins or deposited in arteries producing bioactive lipids believed to contribute to the atherosclerotic inflammatory response. PLA2(s) are elevated in obesity and type 2 diabetes (T2D) but it is not clear which of these conditions is the cause since they frequently coexist. This study attempts to evaluate if high plasma PLA2(s) activities and markers of their effects in lipoproteins are associated with obesity or T2D diabetes, or with both. Total PLA2 and Ca2+‐dependent and ‐independent activities, lipids, lipoproteins, apoAI, and apoB apolipoproteins and affinity of apoB‐lipoproteins for arterial proteoglycans were measured, as well as Inflammation markers. These parameters were evaluated in plasma samples of four groups: (i) apparently healthy controls with normal BMI (nBMI), (ii) obese subjects with no T2D, (iii) patients with T2D but with nBMI, and (iv) obese patients with T2D. PLA2 activities were measured in the presence and absence of Ca2+ and in the presence of specific inhibitors. Obese subjects, with or without T2D, had high activities of total PLA2 and of Ca2+‐dependent and Ca2+‐independent enzymes. The activities were correlated with inflammation markers in obese subjects with and without diabetes and with alterations of low‐density lipoproteins (LDLs) that increased their affinity for arterial proteoglycans. Ca2+‐dependent secretory (sPLA2) enzymes were the main responsible of the obesity‐associated high activity. We speculate that augmented PLA2(s) activity that increases affinity of circulating LDL for arterial intima proteoglycans could be another atherogenic component of obesity.
ProNGF induces TNFα-dependent death of retinal ganglion cells through a p75
NTR
non-cell-autonomous signaling pathway
Authors: Lebrun-Julien Frédéric , Bertrand Mathieu J. , De Backer Olivier , Stellwagen David , Morales Carlos R. , Di Polo Adriana , Barker Philip A.
Published: February 2010

Neurotrophin binding to the p75 neurotrophin receptor (p75
NTR
) activates neuronal apoptosis following adult central nervous system injury, but the underlying cellular mechanisms remain poorly defined. In this study, we show that the proform of nerve growth factor (proNGF) induces death of retinal ganglion cells in adult rodents via a p75
NTR
-dependent signaling mechanism. Expression of p75
NTR
in the adult retina is confined to Müller glial cells; therefore we tested the hypothesis that proNGF activates a non-cell-autonomous signaling pathway to induce retinal ganglion cell (RGC) death. Consistent with this, we show that proNGF induced robust expression of tumor necrosis factor alpha (TNFα) in Müller cells and that genetic or biochemical ablation of TNFα blocked proNGF-induced death of retinal neurons. Mice rendered null for p75
NTR
, its coreceptor sortilin, or the adaptor protein NRAGE were defective in proNGF-induced glial TNFα production and did not undergo proNGF-induced retinal ganglion cell death. We conclude that proNGF activates a non-cell-autonomous signaling pathway that causes TNFα-dependent death of retinal neurons in vivo.
NudC-like protein 2 regulates the LIS1/dynein pathway by stabilizing LIS1 with Hsp90
Authors: Yang Yuehong , Yan Xiaoyi , Cai Yuqi , Lu Yiqing , Si Jianmin , Zhou Tianhua
Published: February 2010

The type I lissencephaly gene product LIS1, a key regulator of cytoplasmic dynein, is critical for cell proliferation, survival, and neuronal migration. However, little is known about the regulation of LIS1. Here, we identify a previously uncharacterized mammalian homolog of
Aspergillus
NudC, NudCL2 (NudC-like protein 2), as a regulator of LIS1. NudCL2 is localized to the centrosome in interphase, and spindle poles and kinetochores during mitosis, a pattern similar to the localization of LIS1 and cytoplasmic dynein. Depletion of NudCL2 destabilized LIS1 and led to phenotypes resembling those of either dynein or LIS1 deficiency. NudCL2 complexed with and enhanced the interaction between LIS1 and Hsp90. Either disruption of the LIS1-Hsp90 interaction with the C terminus of NudCL2 or inhibition of Hsp90 chaperone function by geldanamycin decreased LIS1 stability. Thus, our results suggest that NudCL2 regulates the LIS1/dynein pathway by stabilizing LIS1 with Hsp90 chaperone. This represents a hitherto undescribed mechanism of the LIS1/dynein regulation in mammalian cells.
Neisseria meningitidis
GNA2132, a heparin-binding protein that induces protective immunity in humans
Authors: Serruto Davide , Spadafina Tiziana , Ciucchi Laura , Lewis Lisa A. , Ram Sanjay , Tontini Marta , Santini Laura , Biolchi Alessia , Seib Kate L. , Giuliani Marzia M. , Donnelly John J. , Berti Francesco , Savino Silvana , Scarselli Maria , Costantino Paolo , Kroll J. Simon , O’Dwyer Clíona , Qiu Jiazhou , Plaut Andrew G. , Moxon Richard , Rappuoli Rino , Pizza Mariagrazia , Aricò Beatrice
Published: February 2010

GNA2132 is a
Neisseria meningitidis
antigen of unknown function, discovered by reverse vaccinology, which has been shown to induce bactericidal antibodies in animal models. Here we show that this antigen induces protective immunity in humans and it is recognized by sera of patients after meningococcal disease. The protein binds heparin in vitro through an Arg-rich region and this property correlates with increased survival of the unencapsulated bacterium in human serum. Furthermore, two proteases, the meningococcal NalP and human lactoferrin, cleave the protein upstream and downstream from the Arg-rich region, respectively. We conclude that GNA2132 is an important protective antigen of
N. meningitidis
and we propose to rename it,
N
eisserial
H
eparin
B
inding
A
ntigen (NHBA).
A Guaninine Nucleotide Exchange Factor Is a Component of the Meiotic Spindle Pole Body inSchizosaccharomyces pombe
Authors: Yang Hui-Ju , Neiman Aaron M.
Published: February 2010

Spore morphogenesis in yeast is driven by the formation of membrane compartments that initiate growth at the spindle poles during meiosis II and grow to encapsulate daughter nuclei. Vesicle docking complexes, called meiosis II outer plaques (MOPs), form on each meiosis II spindle pole body (SPB) and serve as sites of membrane nucleation. How the MOP stimulates membrane assembly is not known. Here, we report that SpSpo13, a component of the MOP in Schizosaccharomyces pombe, shares homology with the guanine nucleotide exchange factor (GEF) domain of the Saccharomyces cerevisiae Sec2 protein. ScSec2 acts as a GEF for the small Rab GTPase ScSec4, which regulates vesicle trafficking from the late-Golgi to the plasma membrane. A chimeric protein in which the ScSec2-GEF domain is replaced with SpSpo13 is capable of supporting the growth of a sec2Δ mutant. SpSpo13 binds preferentially to the nucleotide-free form of ScSec4 and facilitates nucleotide exchange in vitro. In vivo, a Spspo13 mutant defective in GEF activity fails to support membrane assembly. In vitro specificity experiments suggest that SpYpt2 is the physiological substrate of SpSpo13. These results demonstrate that stimulation of Rab-GTPase activity is a property of the S. pombe MOP essential for the initiation of membrane formation.
A visual framework for sequence analysis using n-grams and spectral rearrangement
Authors: Maetschke Stefan R. , Kassahn Karin S. , Dunn Jasmyn A. , Han Siew-Ping , Curley Eva Z. , Stacey Katryn J. , Ragan Mark A.
Published: February 2010

Motivation: Protein sequences are often composed of regions that have distinct evolutionary histories as a consequence of domain shuffling, recombination or gene conversion. New approaches are required to discover, visualize and analyze these sequence regions and thus enable a better understanding of protein evolution.

Results: Here, we have developed an alignment-free and visual approach to analyze sequence relationships. We use the number of shared n-grams between sequences as a measure of sequence similarity and rearrange the resulting affinity matrix applying a spectral technique. Heat maps of the affinity matrix are employed to identify and visualize clusters of related sequences or outliers, while n-gram-based dot plots and conservation profiles allow detailed analysis of similarities among selected sequences. Using this approach, we have identified signatures of domain shuffling in an otherwise poorly characterized family, and homology clusters in another. We conclude that this approach may be generally useful as a framework to analyze related, but highly divergent protein sequences. It is particularly useful as a fast method to study sequence relationships prior to much more time-consuming multiple sequence alignment and phylogenetic analysis.

Availability: A software implementation (MOSAIC) of the framework described here can be downloaded from http://bioinformatics.org.au/mosaic/

Contact:  m.ragan@uq.edu.au

Supplementary information:  Supplementary data are available at Bioinformatics online.
Cascleave: towards more accurate prediction of caspase substrate cleavage sites
Authors: Song Jiangning , Tan Hao , Shen Hongbin , Mahmood Khalid , Boyd Sarah E. , Webb Geoffrey I. , Akutsu Tatsuya , Whisstock James C.
Published: February 2010

Motivation: The caspase family of cysteine proteases play essential roles in key biological processes such as programmed cell death, differentiation, proliferation, necrosis and inflammation. The complete repertoire of caspase substrates remains to be fully characterized. Accordingly, systematic computational screening studies of caspase substrate cleavage sites may provide insight into the substrate specificity of caspases and further facilitating the discovery of putative novel substrates.

Results: In this article we develop an approach (termed Cascleave) to predict both classical (i.e. following a P1 Asp) and non-typical caspase cleavage sites. When using local sequence-derived profiles, Cascleave successfully predicted 82.2% of the known substrate cleavage sites, with a Matthews correlation coefficient (MCC) of 0.667. We found that prediction performance could be further improved by incorporating information such as predicted solvent accessibility and whether a cleavage sequence lies in a region that is most likely natively unstructured. Novel bi-profile Bayesian signatures were found to significantly improve the prediction performance and yielded the best performance with an overall accuracy of 87.6% and a MCC of 0.747, which is higher accuracy than published methods that essentially rely on amino acid sequence alone. It is anticipated that Cascleave will be a powerful tool for predicting novel substrate cleavage sites of caspases and shedding new insights on the unknown caspase-substrate interactivity relationship.

Availability:  http://sunflower.kuicr.kyoto-u.ac.jp/∼sjn/Cascleave/

Contact:  jiangning.song@med.monash.edu.au; takutsu@kuicr.kyoto-u.ac.jp; james; whisstock@med.monash.edu.au

Supplementary information:  Supplementary data are available at Bioinformatics online.
Do toads have a jump on how far they hop? Pre-landing activity timing and intensity in forelimb muscles of hoppingBufo marinus
Authors: Gillis Gary B. , Akella Trupti , Gunaratne Rashmi
Published: February 2010

During jumping or falling in humans and various other mammals, limb muscles are activated before landing, and the intensity and timing of this pre-landing activity are scaled to the expected impact. In this study, we test whether similarly tuned anticipatory muscle activity is present in hopping cane toads. Toads use their forelimbs for landing, and we analysed pre-landing electromyographic (EMG) timing and intensity in relation to hop distance for them. coracoradialisandm. anconeus, which act antagonistically at the elbow, and are presumably important in stabilizing the forelimb during landing. In most cases, a significant, positive relationship between hop distance and pre-landing EMG intensity was found. Moreover, pre-landing activation timing ofm. anconeuswas tightly linked to when the forelimbs touched down at landing. Thus, like mammals, toads appear to gauge the timing and magnitude of their impending impact and activate elbow muscles accordingly. To our knowledge these data represent the first demonstration of tuned pre-landing muscle recruitment in anurans and raise questions about how important the visual, vestibular and/or proprioceptive systems are in mediating this response.
Long-term evolution of antigen repertoires among carried meningococci
Authors: Buckee Caroline O. , Gupta Sunetra , Kriz Paula , Maiden Martin C. J. , Jolley Keith A.
Published: February 2010

Most studies of bacterial pathogen populations have been based on isolates collected from individuals with disease, or their contacts, over short time periods. For commensal organisms that occasionally cause disease, such as
Neisseria meningitidis
, however, the analysis of isolates from long-term asymptomatic carriage is necessary to elucidate their evolution and population structure. Here, we use mathematical models to analyse the structuring and dynamics of three vaccine-candidate antigens among carried meningococcal isolates collected over nearly 30 years in the Czech Republic. The data indicate that stable combinations of antigenic alleles were maintained over this time period despite evidence for high rates of recombination, consistent with theoretical models in which strong immune selection can maintain non-overlapping combinations of antigenic determinants in the presence of recombination. We contrast this antigenic structure with the overlapping but relatively stable combinations of the housekeeping genes observed among the same isolates, and use a novel network approach to visualize these relationships.
Mate choice and mate competition by a tropical hummingbird at a floral resource
Authors: Temeles Ethan J. , Kress W. John
Published: February 2010

The influence of male territorial and foraging behaviours on female choice has received little attention in studies of resource-defence mating systems even though such male behaviours are thought to affect variation in their territory quality and mating success. Here we show that female purple-throated carib hummingbirds
Eulampis jugularis
preferred to mate with males that had high standing crops of nectar on their flower territories. A male's ability to maintain high nectar standing crops on his territory not only depended on the number of flowers in his territory, but also on his ability to enhance his territory through the prevention of nectar losses to intruders. We observed that males defended nectar supplies that were two to five times greater than their daily energy needs and consistently partitioned their territories in order to provide some resources to attract intruding females as potential mates. Such territorial behaviour resulted in males defending some flowers for their own food and other flowers as food for intruding females. Collectively, our results suggest that variation in mating success among males is driven primarily by variation in territory quality, which ultimately depends on a male's fighting ability and size.
An experimental test of a fundamental food web motif
Authors: Rip Jason M. K. , McCann Kevin S. , Lynn Denis H. , Fawcett Sonia
Published: February 2010

Large-scale changes to the world's ecosystem are resulting in the deterioration of biostructure—the complex web of species interactions that make up ecological communities. A difficult, yet crucial task is to identify food web structures, or food web motifs, that are the building blocks of this baroque network of interactions. Once identified, these food web motifs can then be examined through experiments and theory to provide mechanistic explanations for how structure governs ecosystem stability. Here, we synthesize recent ecological research to show that generalist consumers coupling resources with different interaction strengths, is one such motif. This motif amazingly occurs across an enormous range of spatial scales, and so acts to distribute coupled weak and strong interactions throughout food webs. We then perform an experiment that illustrates the importance of this motif to ecological stability. We find that weak interactions coupled to strong interactions by generalist consumers dampen strong interaction strengths and increase community stability. This study takes a critical step by isolating a common food web motif and through clear, experimental manipulation, identifies the fundamental stabilizing consequences of this structure for ecological communities.
Reproductive constraints, direct fitness and indirect fitness benefits explain helping behaviour in the primitively eusocial wasp,Polistes canadensis
Authors: Sumner Seirian , Kelstrup Hans , Fanelli Daniele
Published: February 2010

A key step in the evolution of sociality is the abandonment of independent breeding in favour of helping. In cooperatively breeding vertebrates and primitively eusocial insects, helpers are capable of leaving the group and reproducing independently, and yet many do not. A fundamental question therefore is why do helpers help? Helping behaviour may be explained by constraints on independent reproduction and/or benefits to individuals from helping. Here, we examine simultaneously the reproductive constraints and fitness benefits underlying helping behaviour in a primitively eusocial paper wasp. We gave 31 helpers the opportunity to become egg-layers on their natal nests by removing nestmates. This allowed us to determine whether helpers are reproductively constrained in any way. We found that age strongly influenced whether an ex-helper could become an egg-layer, such that young ex-helpers could become egg-layers while old ex-helpers were less able. These differential reproductive constraints enabled us to make predictions about the behaviours of ex-helpers, depending on the relative importance of direct and indirect fitness benefits. We found little evidence that indirect fitness benefits explain helping behaviour, as 71 per cent of ex-helpers left their nests before the end of the experiment. In the absence of reproductive constraints, however, young helpers value direct fitness opportunities over indirect fitness. We conclude that a combination of reproductive constraints and potential for future direct reproduction explain helping behaviour in this species. Testing several competing explanations for helping behaviour simultaneously promises to advance our understanding of social behaviour in animal groups.
The allergen Bet v 1 in fractions of ambient air deviates from birch pollen counts
Authors: Buters J. T. M. , Weichenmeier I. , Ochs S. , Pusch G. , Kreyling W. , Boere A. J. F. , Schober W. , Behrendt H.
Published: February 2010

To cite this article: Buters JTM, Weichenmeier I, Ochs S, Pusch G, Kreyling W, Boere AJF, Schober W, Behrendt H. The allergen Bet v 1 in fractions of ambient air deviates from birch pollen counts. Allergy 2010; 65: 850–858.

Background:  Proof is lacking that pollen count is representative for allergen exposure, also because allergens were found in nonpollen‐bearing fractions of ambient air.

Objective:  We monitored simultaneously birch pollen and the major birch pollen allergen Bet v 1 in different size fractions of ambient air from 2004 till 2007 in Munich, Germany.

Methods:  Air was sampled with a ChemVol® high‐volume cascade impactor equipped with stages for particulate matter (PM)>10 μm, 10 μm>PM>2.5 μm, and 2.5 μm>PM>0.12 μm. Allergen was determined with a Bet v 1‐specific ELISA. Pollen count was assessed with a Burkard pollen trap. We also measured the development of allergen in pollen during ripening.

Results:  About 93 ± 3% of Bet v 1 was found in the PM > 10 μm fraction, the fraction containing birch pollen. We did not measure any Bet v 1 in 2.5 μm > PM > 0.12 μm. Either in Munich no allergen was in this fraction or the allergen was absorbed to diesel soot particles that also deposit in this fraction. Pollen released 115% more Bet v 1 in 2007 than in 2004. Also within 1 year, the release of allergen from the same amount of pollen varied more than 10‐fold between different days. This difference was explained by a rapidly increasing expression of Bet v 1 in pollen in the week just before pollination. Depending on the day the pollen is released during ripening, its potency varies.

Conclusion:  In general, pollen count and allergen in ambient air follow the same temporal trends. However, because a 10‐fold difference can exist in allergen potency of birch pollen, symptoms might be difficult to correlate with pollen counts, but perhaps better with allergen exposure.
Risk factors of new‐onset asthma in adults: a population‐based international cohort study
Authors: Antó J. M. , Sunyer J. , Basagaña X. , Garcia‐Esteban R. , Cerveri I. , De Marco R. , Heinrich J. , Janson C. , Jarvis D. , Kogevinas M. , Kuenzli N. , Leynaert B. , Svanes C. , Wjst M. , Gislason T. , Burney P.
Published: February 2010

To cite this article: Antó JM, Sunyer J, Basagaña X, Garcia‐Esteban R, Cerveri I, de Marco R, Heinrich J, Janson C, Jarvis D, Kogevinas M, Kuenzli N, Leynaert B, Svanes C, Wjst M, Gislason T, Burney P. Risk factors of new‐onset asthma in adults: a population‐based international cohort study. Allergy 2010; 65: 1021–1030

Background:  The occurrence of new‐onset asthma during adulthood is common, but there is insufficient understanding of its determinants including the role of atopy.

Objective:  To assess the risk factors for the development of new‐onset asthma in middle‐aged adults and to compare them according to atopy.

Methods:  A longitudinal analysis of 9175 young adults who participated in two surveys of the European Community Respiratory Health Survey (ECRHS) conducted 9 years apart.

Findings:  We observed 179 cases of new‐onset asthma among 4588 participants who were free of asthma and reported at the beginning of the follow‐up that they had never had asthma (4.5 per 1000 person‐years). In a logistic regression, the following risk factors were found to increase the risk of new‐onset asthma: female gender (OR: 1.97; 95% confidence interval (CI): 1.38,2.81), bronchial hyperresponsiveness (3.25; 2.19,4.83), atopy (1.55;1.08,2.21), FEV1 < 100 % predicted (1.87;1.34,2.62), nasal allergy (1.98;1.39,2.84) and maternal asthma (1.91;1.13;3.21). Obesity, respiratory infections in early life and high‐risk occupations increased the risk of new‐onset asthma although we had limited power to confirm their role. Among the atopics, total IgE and sensitization to cat were independently related to the risk of new‐onset asthma. The proportion of new‐onset asthma attributable to atopy varied from 12% to 21%.

Conclusion:  Adults reporting that they had never had asthma were at a substantial risk of new‐onset asthma as a result of multiple independent risk factors including lung function. Atopy explains a small proportion of new‐onset adult asthma.
Novel exon nucleotide substitution at the splice junction causes a neonatal Marfan syndrome
Authors: Chao S‐C , Chen J‐S , Tsai C‐H , Lin JY‐M , Lin Y‐J , Sun HS
Published: February 2010

Chao S‐C, Chen J‐S, Tsai C‐H, Lin JY‐M, Lin Y‐J, Sun HS. Novel exon nucleotide substitution at the splice junction causes a neonatal Marfan syndrome.

The fibrillin‐1 gene (FBN1) mutations are associated with a broad spectrum of disorders including Marfan syndrome (MFS) and show great clinical heterogeneity. An underrepresentation for mutations leading to premature termination codon (PTC) in FBN1 exons 24–32 was found in neonatal or severe MFS but the underlying cause was unclear. This study thoroughly examined two FBN1 mutations on exons 24–32 region to illustrate the molecular mechanisms underlying these FBN1 mutations on MFS etiology. Two nucleotide substitutions, c.3208G> C, the last nucleotide of exon 26, and c.3209A>G, the first nucleotide of exon 27, affecting the same amino acid, p.D1070H and p.D1070G, respectively, gave very different phenotypes. We demonstrate that c.3208G>C generates two alternatively spliced transcripts, while c.3209A>G does not affect the splicing. We further demonstrate that the aberrantly spliced transcripts do not go through nonsense‐mediated decay, but rather produce unstable, premature protein peptides that are degraded by endoplasmic reticulum associated degradation. The molecular mechanism outlined here defines a model for the pathogenesis of PTC‐containing mutation within the exons 24–32 of FBN1 in MFS. Furthermore, our data suggest that PTC mutation within this region may lead to early lethality in neonatal MFS.
Variable hearing impairment in a DFNB2 family with a novel MYO7A missense mutation
Authors: Hildebrand MS , Thorne NP , Bromhead CJ , Kahrizi K , Webster JA , Fattahi Z , Bataejad M , Kimberling WJ , Stephan D , Najmabadi H , Bahlo M , Smith RJH
Published: February 2010

Hildebrand MS, Thorne NP, Bromhead CJ, Kahrizi K, Webster JA, Fattahi Z, Bataejad M, Kimberling WJ, Stephan D, Najmabadi H, Bahlo M, Smith RJH. Variable hearing impairment in a DFNB2 family with a novel MYO7A missense mutation.

Myosin VIIA mutations have been associated with non‐syndromic hearing loss (DFNB2; DFNA11) and Usher syndrome type 1B (USH1B). We report clinical and genetic analyses of a consanguineous Iranian family segregating autosomal recessive non‐syndromic hearing loss (ARNSHL). The hearing impairment was mapped to the DFNB2 locus using Affymetrix 50K GeneChips; direct sequencing of the MYO7A gene was completed. The Iranian family (L‐1419) was shown to segregate a novel homozygous missense mutation (c.1184G>A) that results in a p.R395H amino acid substitution in the motor domain of the myosin VIIA protein. As one affected family member had significantly less severe hearing loss, we used a candidate approach to search for a genetic modifier. This novel MYO7A mutation is the first reported to cause DFNB2 in the Iranian population and this DFNB2 family is the first to be associated with a potential modifier. The absence of vestibular and retinal defects, and less severe low frequency hearing loss, is consistent with the phenotype of a recently reported Pakistani DFNB2 family. Thus, we conclude this family has non‐syndromic hearing loss (DFNB2) rather than USH1B, providing further evidence that these two diseases represent discrete disorders.
Radical prostatectomy: a systematic review of the impact of hospital and surgeon volume on patient outcome
Authors: Wilson Ailsa , Marlow Nicholas E. , Maddern Guy J. , Barraclough Bruce , Collier Neil A. , Dickinson Ian C. , Fawcett Jonathon , Graham John C.
Published: February 2010

Background:  To assess the impact of hospital and surgeon volume on mortality, morbidity, length of hospital stay and costs of radical prostatectomy (RP).

Methods:  This systematic review identified relevant studies published between 1997 and June 2007. Inclusion of papers was established through application of a predetermined protocol, independent assessment by two reviewers, and a final consensus decision.

Results:  Compared with low volume hospitals, the included studies showed high volume hospitals demonstrated lower rates of mortality, postoperative complications and readmissions, and lower overall hospital costs. High volume surgeons similarly showed lower rates of postoperative complications and shorter length of stay compared with low volume surgeons, but no difference in mortality.

Conclusions:  From the literature obtained, patients undergoing RP performed by high volume providers may have better outcomes compared to low volume providers; however, any move to centralize RP must be further evaluated.
Nonsteroidal anti‐inflammatory drugs‐associated colopathy
Authors: Masannat Yazan A. , Harron Michael , Harinath Gandra
Published: February 2010

Background:  Nonsteroidal anti‐inflammatory drugs (NSAIDs) are commonly used worldwide, and their complications in the upper gastrointestinal tract are well described in the literature and well known to clinicians. However, complications in the large bowel are being increasingly recognized and reported. This review aims to address the different aspects of NSAIDs‐associated colopathy.

Methods:  This is a review article addressing NSAIDs colopathy. A Medline‐based search was performed for articles published between 1950 and 2008 on this condition. Keywords detailed were colonic disease, ulcers, strictures and/or diaphragm strictures. Only articles in the English language were considered.

Results:  The articles identified included letters to the editors, case reports, case series, review articles and few original research papers. The review was structured in a narrative style in different sections addressing pathophysiology, clinical presentation and management.

Conclusions:  NSAIDs colopathy is a rare benign condition. Current evidence only suggests an association with prolonged use of the NSAIDs, however, there are no studies to support the direct causation. The presentation is non‐specific, and the commonest findings on endoscopy are ulceration and diaphragm‐like strictures. The importance of identifying this condition is to prevent complications and also to be able to differentiate it from other conditions such as inflammatory bowel disease (IBD) and malignancy.
Brief screening tool for mild cognitive impairment in older Japanese: Validation of the Japanese version of the Montreal Cognitive Assessment
Authors: Fujiwara Yoshinori , Suzuki Hiroyuki , Yasunaga Masashi , Sugiyama Mika , Ijuin Mutsuo , Sakuma Naoko , Inagaki Hiroki , Iwasa Hajime , Ura Chiaki , Yatomi Naomi , Ishii Kenji , Tokumaru Aya M , Homma Akira , Nasreddine Ziad , Shinkai Shoji
Published: February 2010

Aim:  The Montreal Cognitive Assessment (MoCA), developed by Dr Nasreddine (Nasreddine et al. 2005), is a brief cognitive screening tool for detecting older people with mild cognitive impairment (MCI). We examined the reliability and validity of the Japanese version of the MoCA (MoCA‐J) in older Japanese subjects.

Methods:  Subjects were recruited from the outpatient memory clinic of Tokyo Metropolitan Geriatric Hospital or community‐based medical health check‐ups in 2008. The MoCA‐J, the Mini‐Mental State Examination (MMSE), the revised version of Hasegawa's Dementia Scale (HDS‐R), Clinical Dementia Rating (CDR) scale, and routine neuropsychological batteries were conducted on 96 older subjects. Mild Alzheimer's disease (AD) was found in 30 subjects and MCI in 30, with 36 normal controls.

Results:  The Cronbach's alpha of MoCA‐J as an index of internal consistency was 0.74. The test–retest reliability of MoCA, using intraclass correlation coefficient between the scores at baseline survey and follow‐up survey 8 weeks later was 0.88 (P < 0.001). MoCA‐J score was highly correlated with MMSE (r = 0.83, P < 0.001), HDS‐R (r = 0.79, P < 0.001) and CDR (r = −0.79, P < 0.001) scores. The areas under receiver–operator curves (AUC) for predicting MCI and AD groups by the MoCA‐J were 0.95 (95% confidence interval [CI] = 0.90–1.00) and 0.99 (95% CI = 0.00–1.00), respectively. The corresponding values for MMSE and HDS‐R were 0.85 (95% CI = 0.75–0.95) and 0.97 (95% CI = 0.00–1.00), and 0.86 (95% CI = 0.76–0.95) and 0.97 (95% CI = 0.00–1.00), respectively. Using a cut‐off point of 25/26, the MoCA‐J demonstrated a sensitivity of 93.0% and a specificity of 87.0% in screening MCI.

Conclusion:  The MoCA‐J could be a useful cognitive test for screening MCI, and could be recommended in a primary clinical setting and for geriatric health screening in the community. Geriatr Gerontol Int 2010; 10: 225–232.