bluuebunny/crossref_metadata_2025 huggingface dataset:
Cetaceans of Southeast Alaska: distribution and seasonal occurrence
Authors: Dahlheim Marilyn E. , White Paula A. , Waite Janice M.
Published: December 2008

Aim  To assess the distribution, group size, seasonal occurrence and annual trends of cetaceans.

Location  The study area included all major inland waters of Southeast Alaska.

Methods  Between 1991 and 2007, cetacean surveys were conducted by observers who kept a constant watch when the vessel was underway and recorded all cetaceans encountered. For each species, we examined distributional patterns, group size, seasonal occurrence and annual trends. Analysis of variance (anovaF) was used to test for differences in group sizes between multiple means, and Student’s t‐test was used to detect differences between pairwise means. Cetacean seasonal occurrence and annual trends were investigated using a generalized linear model framework.

Results  Humpback whales (Megaptera novaeangliae) were seen throughout the region, with numbers lowest in spring and highest in the fall. Fin whale (Balaenoptera physalus) and minke whale (Balaenoptera acutorostrata) distributions were more restricted than that reported for humpback whales, and the low number of sightings precluded evaluating seasonal trends. Three killer whale (Orcinus orca) eco‐types were documented with distributions occurring throughout inland waters. Seasonal patterns were not detected or could not be evaluated for resident and offshore killer whales, respectively; however, the transient eco‐type was more abundant in the summer. Dall’s porpoise (Phocoenoides dalli) were distributed throughout the region, with more sightings in spring and summer than in fall. Harbour porpoise (Phocoena phocoena) distribution was clumped, with concentrations occurring in the Icy Strait/Glacier Bay and Wrangell areas and with no evidence of seasonality. Pacific white‐sided dolphins (Lagenorhynchus obliquidens) were observed only occasionally, with more sightings in the spring. For most species, group size varied on both an annual and seasonal basis.

Main conclusions  Seven cetacean species occupy the inland waters of Southeast Alaska, with distribution, group size, seasonal occurrence and annual trends varying by species. Future studies that compare spatial and temporal patterns with other features (e.g. oceanography, prey resources) may help in identifying the key factors that support the high density and biodiversity of cetaceans found in this region. An increased understanding of the region’s marine ecology is an essential step towards ensuring the long‐term conservation of cetaceans in Southeast Alaska.
Validation study of a portable monitoring device for identifying OSA in a symptomatic patient population
Authors: TO Kin‐Wang , CHAN Wing‐Chi , CHAN Tat‐On , TUNG Alvin , NGAI Jenny , NG Susanna , CHOO Kah‐Lin , HUI David S.
Published: December 2008

Background and objective:  Obstructive sleep apnoea syndrome (OSAS) is a common disorder associated with early atherosclerosis, diabetes mellitus, ischaemic heart disease and cerebrovascular disease. The gold standard for confirming OSAS is based on an attended overnight polysomnography (PSG) in a sleep laboratory; however lack of health‐care resources creates long waiting times for patient access to this diagnostic test. This study evaluated the ability of a portable sleep‐monitoring device to identify patients in Hong Kong with suspected OSAS.

Methods:  Patients with symptoms of OSAS were invited to use the ARES (apnoea risk evaluation system) concurrently with an attended inpatient PSG. Several sets of AHI were generated by the ARES provider based on different oxygen desaturation criteria and surrogate parameters of arousal. The results were compared against PSG to determine the optimal sensitivity and specificity.

Results:  There were 141 patients who completed the study successfully. Results of AHI from the ARES study were presented in the order of different scoring criteria––4% oxygen desaturation alone, obstructive events with 3% oxygen desaturation and obstructive events with 1% desaturation plus surrogate arousal criteria. The sensitivity was 0.84 (95% confidence interval (CI): 0.77–0.90), 0.89 (95% CI: 0.89–0.94) and 0.97 (95% CI: 0.94–0.99), respectively. The specificity was 1, 1 and 0.63 (95% CI: 0.55–0.71), respectively. The receiver operating curve had an area of 0.96, 0.97 and 0.98, respectively. The kappa coefficient varied from 0.24 to 0.55 for agreement of severity between PSG and ARES. The likelihood ratio positive and the likelihood ratio negative were 2.61, infinity, infinity and 0.16, 0.11, 0.05, respectively, in the order of oxygen desaturation described earlier.

Conclusions:  The ARES device has reasonable sensitivity and specificity for diagnosing severe OSAS in symptomatic Chinese patients. There is moderate agreement between ARES and PSG in the diagnosis of severe disease, but less agreement in patients with mild/moderate disease.
Tako‐tsubo‐like cardiomyopathy after EpiPen administration
Authors: Zubrinich C. M. , Omar Farouque H. M. , Rochford S. E. , Sutherland M. F.
Published: December 2008

Tako‐tsubo‐like cardiomyopathy is characterized by acute chest pain, electrocardiographic changes and increased cardiac enzymes in the absence of obstructive coronary vessel disease. We describe the development of tako‐tsubo‐like cardiomyopathy in an elderly woman after the use of an EpiPen for generalized urticaria and angioedema. As adrenaline may participate in the pathogenesis of this condition, the need for careful patient selection and education in the use of adrenaline self‐injectors remains imperative.
The experiences of disabled pupils and their families
Authors: Lewis Ann , Davison Ian , Ellins Jean , Niblett Louise , Parsons Sarah , Robertson Christopher , Sharpe Jeremy
Published: December 2008

In this article, Ann Lewis, Professor of Education at the University of Birmingham, and Ian Davison, Jean Ellins, Louise Niblett, Sarah Parsons, Christopher Robertson and Jeremy Sharpe from the research team provide a summary of discussions and selected recommendations arising from four linked projects run between 2004 and 2006. The projects were funded by the Disability Rights Commission (DRC) and looked into the experiences of disabled pupils and their families across England, Scotland and Wales. A central aim of the research was to identify the key concerns and priorities in relation to their experiences of education for children and young people with special educational needs (SEN) or disabilities and their families in the UK. The research encompassed a UK‐wide parent survey (N=1776); in‐depth case studies of individual children and young people (N=36); group case studies (of, for example, school councils) (N=3); and a series of project advisory groups involving disabled people. Underlying these aspects was an emphasis on the importance and validity of hearing directly from (potentially all) children and young people themselves. Thus the work meshes closely with initiatives worldwide concerning the recognition of children's‘voice’in matters that concern them. The authors are not aware of any comparable evidence which focuses in‐depth on a wide cross‐section of pupils with disabilities or special needs and their families in the UK‐wide educational context and which is located alongside concurrent authoritative data concerning the views of parents and carers.
A review of recent developments in the role of the SENCo in the UK
Authors: Mackenzie Suzanne
Published: December 2008

In this discussion paper, Suzanne Mackenzie, senior lecturer with responsibility for the special educational needs BA and MA programmes at the University of East London, reviews previous research in order to identify changes in the role of the special educational needs co‐ordinator (SENCo) in schools in the UK. She provides an overview of the SENCo role from an historical perspective and discusses the diverse and challenging nature of the SENCo's work. She notes a marked lack of consistency, over time and across contexts, in interpretations of the SENCo role and examines variation in workload, status and position within school hierarchies. Suzanne Mackenzie highlights the gaps in current research on the work of SENCos and makes suggestions for future developments in the role. She focuses, in particular, on the ways in which SENCo ‘effectiveness’ can be determined.
Arsenic uptake and metabolism in plants
Authors: Zhao F. J. , Ma J. F. , Meharg A. A. , McGrath S. P.
Published: December 2008

Arsenic (As) is an element that is nonessential for and toxic to plants. Arsenic contamination in the environment occurs in many regions, and, depending on environmental factors, its accumulation in food crops may pose a health risk to humans. Recent progress in understanding the mechanisms of As uptake and metabolism in plants is reviewed here. Arsenate is taken up by phosphate transporters. A number of the aquaporin nodulin26‐like intrinsic proteins (NIPs) are able to transport arsenite, the predominant form of As in reducing environments. In rice (Oryza sativa), arsenite uptake shares the highly efficient silicon (Si) pathway of entry to root cells and efflux towards the xylem. In root cells arsenate is rapidly reduced to arsenite, which is effluxed to the external medium, complexed by thiol peptides or translocated to shoots. One type of arsenate reductase has been identified, but its in planta functions remain to be investigated. Some fern species in the Pteridaceae family are able to hyperaccumulate As in above‐ground tissues. Hyperaccumulation appears to involve enhanced arsenate uptake, decreased arsenite‐thiol complexation and arsenite efflux to the external medium, greatly enhanced xylem translocation of arsenite, and vacuolar sequestration of arsenite in fronds. Current knowledge gaps and future research directions are also identified.

Contents

Summary
777

I.
Introduction
777

II.
Mechanisms of arsenic uptake and efflux
778

III.
Rhizosphere interactions
782

IV.
Arsenic metabolism in planta
783

V.
Long‐distance translocation of arsenic
786

VI.
Arsenic hyperaccumulation
788

VII.
Conclusions
788

Acknowledgements
789

References
789
CONIFEROUS WOOD PULP IN TRADITIONAL KOREAN PAPER BETWEEN THE 15TH AND 18TH CENTURIES ad*
Authors: YUM H. , SINGER B. W. , BACON A.
Published: December 2008

One hundred and sixty‐nine fibre samples from books in the Korean collection and 68 samples from books in the Japanese collection at the British Library were analysed. A further 15 samples of Korean paper from a private collection were also examined. The analysis confirmed that most of the papers contained mulberry species (Moraceae family) as the main papermaking material, and other materials, such as hemp, rice straw and reed, which have been commonly known as supplements to traditional Korean papermaking. However, 15 Korean papers and one Japanese paper dating between ad 1498 and 1798 appeared to include coniferous wood fibres. This substantial find supports a previous single find of a coniferous wood fibre in Korean paper. The dates of most of these papers containing wood fibres precede the use of wood pulps in European paper.
Certificate of Need (CON) for Cardiac Care: Controversy over the Contributions of CON
Authors: Ho Vivian , Ku‐Goto Meei‐Hsiang , Jollis James G.
Published: December 2008

Objectives. To test whether state Certificate of Need (CON) regulations influence procedural mortality or the provision of coronary artery bypass graft surgery (CABG) and percutaneous coronary interventions (PCI).

Data Sources. Medicare inpatient claims obtained for 1989–2002 for patients age 65+ who received CABG or PCI.

Study Design. We used differences‐in‐differences regression analysis to compare states that dropped CON during the sample period with states that kept the regulations. We examined procedural mortality, the number of hospitals in the state performing CABG or PCI, mean hospital volume, and statewide procedure volume for CABG and PCI.

Principal Findings. States that dropped CON experienced lower CABG mortality rates relative to states that kept CON, although the differential is not permanent. No such mortality difference is found for PCI. Dropping CON is associated with more providers statewide and lower mean hospital volume for both CABG and PCI. However, statewide procedure counts remain the same.

Conclusions. We find no evidence that CON regulations are associated with higher quality CABG or PCI. Future research should examine whether the greater number of hospitals performing revascularization after CON removal raises expenditures due to the building of more facilities, or lowers expenditures due to enhanced price competition.
Interactive Effects of Harvest and Deer Herbivory on the Population Dynamics of American Ginseng
Authors: FARRINGTON SUSAN J. , MUZIKA ROSE‐MARIE , DREES DAN , KNIGHT TIFFANY M.
Published: December 2008

Abstract:  Few demographic models for any species consider the role of multiple, interacting ecological threats. Many forest herbs are heavily browsed by white‐tailed deer (Odocoileus virginianus) and a number of these are also harvested for the medicinal, floral, or horticultural trades. Previous studies of the viability of American ginseng (Panax quinquefolius) have separately examined the effects of harvesting and deer herbivory. We followed individually marked ginseng plants in 6 populations for 8 years and documented deer browse levels, conducted helicopter surveys to estimate the deer herd size, and documented 2 ginseng harvests. We used this long‐term data set to develop a stochastic demographic model that quantified the separate and interactive role of these threats to ginseng viability. Although harvesting and deer herbivory negatively affected ginseng population growth, their effects were not additive. Deer herbivory negatively affected population growth in the absence but not in the presence of harvesting. Life table response experiments revealed that in the presence of harvesting, deer herbivory had some positive effects on vital rates because browsed plants were less apparent to harvesters. Ginseng populations that were harvested responsibly (i.e., planting seeds from harvested individuals) had higher growth rates than those that were harvested irresponsibly. We concluded that both deer populations and harvesting must be managed to ensure sustainable populations of American ginseng. Our findings underscore the importance of long‐term monitoring to assess threats to viability and the need for a broad ecological understanding of the complexity of ecosystem management.
Pyric Herbivory: Rewilding Landscapes through the Recoupling of Fire and Grazing
Authors: FUHLENDORF SAMUEL D. , ENGLE DAVID M. , KERBY JAY , HAMILTON ROBERT
Published: December 2008

Abstract:  Our understanding of fire and grazing is largely based on small‐scale experimental studies in which treatments are uniformly applied to experimental units that are considered homogenous. Any discussion of an interaction between fire and grazing is usually based on a statistical approach that ignores the spatial and temporal interactions on complex landscapes. We propose a new focus on the ecological interaction of fire and grazing in which each disturbance is spatially and temporally dependent on the other and results in a landscape where disturbance is best described as a shifting mosaic (a landscape with patches that vary with time since disturbance) that is critical to ecological structure and function of many ecosystems. We call this spatiotemporal interaction pyric herbivory (literal interpretation means grazing driven by fire). Pyric herbivory is the spatial and temporal interaction of fire and grazing, where positive and negative feedbacks promote a shifting pattern of disturbance across the landscape. We present data we collected from the Tallgrass Prairie Preserve in the southern Great Plains of North America that demonstrates that the interaction between free‐roaming bison (Bison bison) and random fires promotes heterogeneity and provides the foundation for biological diversity and ecosystem function of North American and African grasslands. This study is different from other studies of fire and grazing because the fires we examined were random and grazing animals were free to roam and select from burned and unburned patches. For ecosystems across the globe with a long history of fire and grazing, pyric herbivory with any grazing herbivore is likely more effective at restoring evolutionary disturbance patterns than a focus on restoring any large vertebrate while ignoring the interaction with fire and other disturbances.
The Language of Intoxication: Preliminary Investigations
Authors: Levitt Ash , Sher Kenneth J. , Bartholow Bruce D.
Published: December 2008

Background:  The extensive vocabulary individuals use to describe alcohol’s subjective effects has largely gone unexamined in contemporary alcohol research. The present study examined the language drinkers use to describe their own intoxication. It is argued that this language can provide a more complete characterization of alcohol’s subjective effects than is available from existing objective and subjective measures of alcohol use and can inform future self‐report research.

Method:  Toward this goal, a preliminary, cross‐sectional, web‐based study of the familiarity and usage of current intoxication‐related words was conducted in 2 different samples (n = 290 and 146, respectively) of university undergraduates.

Results:  Exploratory factor analyses using data from the first sample and confirmatory factor analyses using data from the second sample similarly showed that commonly used terms loaded onto 2 factors, which directly reflected the number of drinks required to be considered moderately or heavily intoxicated, respectively. Gender differences were also found in the familiarity and self‐use of some terms across both samples.

Conclusions:  The findings suggest that alcohol researchers include multiple intoxication‐related terms in future self‐report research, and to periodically assess current intoxication‐related vocabulary considering demographic, generational, and socio‐cultural differences.
α2A‐Adrenergic Receptor Signaling Underlies Synergistic Enhancement of Ethanol‐Induced Behavioral Impairment by Clonidine
Authors: Bender Tara Summer , Abdel‐Rahman Abdel A.
Published: December 2008

Background: We tested the hypothesis that central α2A‐adrenergic receptor (α2AAR) signaling plays a key role in clonidine‐ethanol evoked synergistic behavioral impairment.

Methods: Male Sprague‐Dawley rats, with intracisternal and jugular vein cannulae implanted 6 days earlier, were tested for drug‐induced behavioral impairment. The latter was assessed as the duration of loss of righting reflex (LORR) and rotorod performance every 15 minutes until the rat recovered to the baseline walk criterion (180 seconds). In a separate cohort, c‐Fos expression in locus coeruleus (LC) and cerebellum was determined as a marker of neuronal activity following drug treatment.

Results: Rats that received clonidine (60 μg/kg, i.v.) followed by ethanol (1 g/kg, i.v.) exhibited synergistic impairment of rotorod performance and LORR. The mixed α2AAR and I1‐imidazoline receptor agonist clonidine (30, 60, and 90 μg/kg) synergistically and dose‐dependently enhanced behavioral impairment elicited by ethanol (1 g/kg). Possible involvement of I1‐imidazoline receptors was ruled out because selective I1‐agonist rilmenidine (300 μg/kg, i.v.) did not cause behavioral impairment alone or enhance ethanol‐evoked behavioral impairment. Pharmacological blockade of central α2AAR (RX821002, 0.3 mg i.c.) abolished the synergy between clonidine and ethanol; the behavioral response caused by the drug combination was similar to that caused by ethanol alone. Conversely, involvement of central α2BAR in the interaction was ruled out because blockade of central α2BAR (ARC‐239) independently evoked a strong sedative effect. Clonidine (60 μg/kg) or ethanol (1 g/kg) alone increased, but their combination decreased, c‐Fos levels in LC, while inconsistent c‐Fos responses were observed in cerebellum.

Conclusions: Central α2AAR, but not I1‐imidazoline or α2BAR, signaling is implicated in the synergistic enhancement of ethanol‐evoked behavioral impairment by clonidine. Although the mechanism of c‐Fos response remains to be investigated, this neurochemical response highlights the LC as a neuroanatomical target for clonidine‐ethanol behavioral interaction.
The History ofToxoplasma gondii—The First 100 Years
Authors: DUBEY JITENDER P.
Published: December 2008

ABSTRACT.In this paper the history ofToxoplasma gondiiand toxoplasmosis is reviewed. This protozoan parasite was first discovered in 1908 and named a year later. Its medical importance remained unknown until 1939 whenT. gondiiwas identified in tissues of a congenitally infected infant, and veterinary importance became known when it was found to cause abortion storms in sheep in 1957. The discovery of aT. gondiispecific antibody test, Sabin–Feldman dye test in 1948 led to the recognition thatT. gondiiis a common parasite of warm‐blooded hosts with a worldwide distribution. Its life cycle was not discovered until 1970 when it was found that felids are its definitive host and an environmentally resistant stage (oocyst) is excreted in feces of infected cats. The recent discovery of its common infection in certain marine wildlife (sea otters) indicates contamination of our seas withT. gondiioocysts washed from land. Hygeine remains the best preventive measure because currently there is no vaccine to prevent toxoplasmosis in humans.
Gene Cloning and Biochemical Characterization of an Alcohol Dehydrogenase from Euglena gracilis1
Authors: PALMA‐GUTIÉRREZ HELGA N. , RODRÍGUEZ‐ZAVALA JOSÉ SALUD , JASSO‐CHÁVEZ RICARDO , MORENO‐SÁNCHEZ RAFAEL , SAAVEDRA EMMA
Published: December 2008

ABSTRACT. Euglena gracilis is a freshwater free‐living organism able to grow with ethanol as carbon source; to facilitate this metabolism several alcohol dehydrogenase (ADH) activities have been detected. We report the gene cloning, over‐expression, and biochemical characterization of a medium‐chain NAD+‐dependent ADH from E. gracilis (EgADH). The enzyme's amino acid sequence displayed the highest percentages of similarity and identity with ADHs of bacteria and fungi. In the predicted three‐dimensional model, all the residues involved in Zn2+, cofactor, and substrate binding were conserved. A conventional signal peptide for import into mitochondria could not be clearly identified. The protein of 37 kDa was over‐expressed, purified to homogeneity, and kinetically characterized. The enzyme's optimal pH was 7.0 for ethanol oxidation displaying a Vm of 11.7±3.6 U/mg protein and a Km of 3.2±0.7 mM for this substrate. Isopropanol and isopentanol were also utilized, although with less efficiency. It showed specificity for NAD+ with a Km value of 0.39±0.1 mM and Mg2+ or Zn2+ were essential for activity. The recombinant EgADH reported here may help to elucidate the roles that different ADHs have on the metabolism of short‐ and long‐chain alcohols in this microorganism.
Structural and mechanistic insights into Mps1 kinase activation
Authors: Wang Wei , Yang Yuting , Gao Yuefeng , Xu Quanbin , Wang Feng , Zhu Songcheng , Old William , Resing Katheryn , Ahn Natalie , Lei Ming , Liu Xuedong
Published: December 2008

Mps1 is one of the several essential kinases whose activation is required for robust mitotic spindle checkpoint signalling. The activity of Mps1 is tightly regulated and increases dramatically during mitosis or in response to spindle damage. To understand the molecular mechanism underlying Mps1 regulation, we determined the crystal structure of the kinase domain of Mps1. The 2.7‐Å‐resolution crystal structure shows that the Mps1 kinase domain adopts a unique inactive conformation. Intramolecular interactions between the key Glu residue in the αC helix of the N‐terminal lobe and the backbone amides in the catalytic loop lock the kinase in the inactive conformation. Autophosphorylation appears to be a priming event for kinase activation. We identified Mps1 autophosphorylation sites in the activation and the P+1 loops. Whereas activation loop autophosphorylation enhances kinase activity, autophosphorylation at the P+1 loop (T686) is associated with the active kinase. Mutation of T686 autophosphorylation site impairs both autophosphorylation and transphosphorylation. Furthermore, we demonstrated that phosphorylation of T676 may be a priming event for phosphorylation at T686. Finally, we identified two critical lysine residues in the loop between helices αEF and αF that are essential for substrate recruitment and maintaining high levels of kinase activity. Our studies reveal critical biochemical mechanisms for Mps1 kinase regulation.
Up‐regulation of reverse cholesterol transport key players and rescue from global inflammation by ApoA‐IMilano
Authors: Cimmino Giovanni , Ibanez Borja , Vilahur Gemma , Speidl Walter S. , Fuster Valentin , Badimon Lina , Badimon Juan J.
Published: December 2008

Recombinant‐ApoA‐IM (rApoA‐IM) administration has been shown to regress and stabilize atherosclerotic plaques. However, the mechanisms responsible for these beneficial effects are not fully understood. The aims of the present study were to define whether the benefits of rApoA‐IM treatment were mediated via an enhanced reverse cholesterol transport (RCT) and/or anti‐inflammation‐related mechanisms. Advanced aortic lesions were induced in New Zealand White rabbits (n= 16). Animals were randomized to placebo or rApoA‐IM (rApoA‐IM/phospholipids; ETC‐216), two infusions 4 days apart. Four days after last dose, aortas and livers were processed for cholesterol content, expression of RCT‐related receptors (ATP‐binding cassette A‐1 [ABCA‐1] and scavenger receptor BI [SR‐BI]), and inflammation‐related markers (inducible nitric oxide synthase [iNOS] and capase‐3). Oxidative stress was assessed in the vessel wall and in plasma. rApoA‐IM administration resulted in a significant reduction in the hepatic and aortic cholesterol content without differences in plasma levels. This effect was associated with an up‐regulation of vessel wall ABCA‐1, as well as a hepatic and arterial‐wall SR‐BI up‐regulation. Systemic and atherosclerotic‐plaque inflammation markers were significantly reduced by the rApoA‐IM administration, as demonstrated by a reduction in circulating oxidative stress markers and prostaglandin F1‐α levels, and the down‐regulation of the iNOS and caspase 3 in the aortic lesions. rApoA‐IM up‐regulated the ABCA‐1 and SR‐BI levels to a greater extent than the wild‐type form of apoA‐I in in vitro studies done with lipid‐rich macrophages. Our data suggest that rApoA‐IM administration enhances RCT and induces a ‘rescue’ from the global inflammatory status associated with atherosclerotic disease. The Milano form of apoA‐I seems to be more efficient in RCT than the apoA‐I wild‐type.
Isolation and characterization of DUSP11, a novel p53 target gene
Authors: Caprara Greta , Zamponi Raffaella , Melixetian Marina , Helin Kristian
Published: December 2008

p53 regulates the expression of genes involved in cell cycle control, apoptosis and DNA damage repair. Here we demonstrate that DUSP11 (dual specificity phosphatase 11), a member of the protein tyrosine phosphatase family that binds to RNA‐RNP complexes and RNA splicing factors, is a p53 target gene. Consistent with this, the expression of DUSP11 is induced in a p53‐dependent manner after treatment with DNA damaging agents. Chromatin immunoprecipitation analysis showed that p53 binds to 2 putative p53 DNA binding sites in the promoter region of DUSP11. Colony formation and proliferation assays demonstrated that the ectopic expression of wild‐type, but not catalytical inactive, DUSP11 leads to growth arrest. Furthermore inhibition of DUSP11 expression by shRNA increases the proliferation of normal and DNA damaged cells in tissue culture. Finally we show that the splicing factor SAM68 (Src‐associated protein in mitotic cells) binds to DUSP11 in vitro and in vivo. Taken together these results suggest that DUSP11 contributes to p53‐dependent inhibition of cell proliferation and that it might be involved in regulating RNA splicing through SAM68.
How does plant richness affect pollinator richness and temporal stability of flower visits?
Authors: Ebeling Anne , Klein Alexandra‐Maria , Schumacher Jens , Weisser Wolfgang W. , Tscharntke Teja
Published: December 2008

Pollinators play a key role in the reproduction of most plant species, and pollinator and plant diversity are often related. We studied an experimental gradient of plant species richness for a better understanding of plant–pollinator community interactions and their temporal variability, because in non‐experimental field surveys plant richness is often confounded with gradients in management, soil fertility, and community composition. We observed pollinator species richness and frequency of visits six times in 73 plots over two years, and used advanced statistical analysis to account for the high number of zeroes that often occur in count data of rare species. The frequency of pollinator visits increased linearly with both the blossom cover and the number of flowering plant species, which was closely related to the total number of plant species, whereas the number of pollinator species followed a saturation curve. The presence of particularly attractive plant species was only important for the frequency of flower visits, but not to the richness of pollinators. Plant species richness, blossom cover, and the presence of attractive plant species enhanced the temporal stability in the frequency of pollinator visits.

In conclusion, grasslands with high plant diversity enhance and stabilize frequent and diverse flower visitations, which should sustain effective pollination and plant reproduction.
Sex allocation in fungus‐growing ants: worker or queen control without symbiont‐induced female bias
Authors: Dijkstra Michiel B. , Boomsma Jacobus J.
Published: December 2008

The fungal cultivars of fungus‐growing ants are vertically transmitted by queens but not males. Selection would therefore favor cultivars that bias the ants’ sex ratio towards gynes, beyond the gyne bias that is optimal for workers and queens. We measured sex allocation in 190 colonies of six sympatric fungus‐growing ant species. As predicted from relatedness, female bias was greater in four singly mated Sericomyrmex and Trachymyrmex species than in two multiply mated Acromyrmex species. Colonies tended to raise mainly a single sex, which could be partly explained by variation in queen number, colony fecundity, and fungal garden volume for Acromyrmex and Sericomyrmex, but not for Trachymyrmex. Year of collection, worker number and mating frequency of Acromyrmex queens did not affect the colony sex ratios. We used a novel sensitivity analysis to compare the population sex allocation ratios with the theoretical queen and worker optima for a range of values of k, the correction factor for sex differences in metabolic rate and fat content. The results were consistent with either worker or queen control, but never with fungal control for any realistic value of k. We conclude that the fungal symbiont does not distort the ants’ sex ratio in these species.
Temporal clumping of prey and coexistence of unequal interferers: experiments on social forager groups of brown trout feeding on invertebrate drift
Authors: Jönsson Mikael , Skov Christian , Koed Anders , Anders Nilsson P.
Published: December 2008

Environmental fluctuations have been proposed to enhance the coexistence of competing phenotypes. Evaluations are here presented on the effects of prey density and short‐term temporal clumping of prey availability on the relative foraging success of unequal interferers in social forager groups of juvenile brown troutSalmo truttafeeding on drifting invertebrate prey (frozen chironomids). Groups of three trout with established linear dominance hierarchies (dominant, intermediate and subordinate) were subjected to three different total numbers of prey, combined with three different levels of temporal clumping of prey arrival, resulting in nine treatment combinations. Higher total number of prey increased the consumption for all dominance ranks, while higher temporal clumping decreased the consumption for the dominant individuals and increased the consumption for the subordinate individuals. The proportion of prey eaten was smaller at high prey numbers. Similarly, there was a trend that increased temporal clumping also decreased the proportion of prey eaten. We conclude that density and temporal clumping of prey contribute to the coexistence of unequal interferers, and that there is a potential positive feedback between prey behaviour and phenotypic coexistence through decreased per capita predation risk for prey that drift synchronously in high densities.
Wealth as a source of density dependence in human population growth
Authors: Bauch Chris T.
Published: December 2008

In modern industrialized countries, human birth rates have been declining persistently for decades. In many cases they have now fallen below the replacement threshold. However, unlike in natural populations where population growth is constrained by limited resources, birth rates in modern industrialized countries are negatively correlated with resource availability. Here, declining birth rates in human populations are shown to be a manifestation of density‐dependent population growth brought on by socioeconomic development. This is demonstrated by combining empirical power law relations between population size, gross domestic product (GDP) per capita, and fertility in a simple theoretical model describing population dynamics in developed countries. For a closed population, the model exhibits growth to a globally stable equilibrium population size, for both national and city populations. A version of the model that is open with respect to immigration and the influence of foreign technology and capital exhibits a good fit to long‐term time series data on population size, GDP per capita, and birth rates for the United States, France and Japan.
Actinomycotic canaliculitis: resolution following surgery and short topical antibiotic treatment
Authors: Baldursdóttir Eyrún , Sigurdsson Haraldur , Jónasson Lárus , Gottfredsson Magnús
Published: December 2008

Purpose:  This study aimed to study the incidence and clinical characteristics of patients diagnosed with actinomycotic canaliculitis in Iceland.

Methods:  We present a nationwide, retrospective case series for which cases were identified by searches of hospital diagnostic registries and pathology databases. Case histories were reviewed and histopathological analysis repeated to confirm the diagnosis.

Results:  Nine cases of actinomycotic canaliculitis were diagnosed in Iceland during 1988–2007. Subjects included six women and three men and represented 16% of all patients diagnosed with actinomycosis in the country. The incidence was 0.16 cases/100 000 inhabitants/year. Age‐specific incidence rates were 0.59 cases/100 000 inhabitants/year for the 40–59‐year‐old age group and 1.37 cases/100 000 inhabitants/year for individuals aged 60–79 years. All patients underwent a three‐way snip procedure and 1 week of topical antibacterial therapy.

Conclusions:  Actinomycotic canaliculitis is an uncommon condition which frequently eludes diagnosis. Topical antibiotics for 1 week may be sufficient following surgery, a finding which contrasts with previous reports.
Reaction time during semi‐automated kinetic perimetry (SKP) in patients with advanced visual field loss
Authors: Nowomiejska Katarzyna , Vonthein Reinhard , Paetzold Jens , Zagorski Zbigniew , Kardon Randy , Schiefer Ulrich
Published: December 2008

Purpose:  This study aimed to evaluate reaction time (RT) in patients with advanced visual field (VF) loss using semi‐automated kinetic perimetry (SKP).

Methods:  Seventy‐eight patients with advanced VF loss caused by glaucoma (31) or retinitis pigmentosa (19), homonymous VF loss caused by post‐chiasmal lesions (18) and unilateral anterior ischaemic optic neuropathy (AION) (10) were examined with SKP (Octopus 101 perimeter). One eye in each patient was enrolled. Additionally, VFs in the 10 healthy fellow eyes of the patients with AION were compared with those in the 10 affected eyes. Reaction time was assessed during the SKP session by presenting kinetic stimuli (III4e) with constant angular velocities of 3 °/second moving linearly along so‐called ‘RT vectors’ at four different locations inside the III4e isoptre. Each stimulus presentation was repeated four times in randomized order.

Results:  The geometric mean RT was 794 ms (95% reference interval [RI] 391–1615 ms) in patients with glaucoma, 702 ms (95% RI 306–1608 ms) in patients with retinitis pigmentosa and 675 ms (95% RI 312–1460 ms) in patients with hemianopia. Increases in RT for every 1 ° of eccentricity were 1%, 0.9% and 0.4%, respectively. The geometric mean RT in the 10 patients with unilateral optic neuropathy was 644 ms in affected eyes and 435 ms in unaffected eyes, reflecting an increase of 51% (95% confidence interval 42–62%).

Conclusions:  We found substantial inter‐subject variability in RT in patients with advanced VF loss. It is possible to correct the position of the isoptres by assessing individual RT. There were no relevant differences in RT between the disease groups. Reaction time increases with eccentricity. In monocular disease (AION), RT is prolonged, compared with in healthy fellow eyes. However, in clinical routine the RT‐related displacement of isoptres is negligible in the vast majority of cases.
Choice of In Vivo Versus Idealized Velocity Boundary Conditions Influences Physiologically Relevant Flow Patterns in a Subject-Specific Simulation of Flow in the Human Carotid Bifurcation
Authors: Wake Amanda K. , Oshinski John N. , Tannenbaum Allen R. , Giddens Don P.
Published: December 2008

Accurate fluid mechanics models are important tools for predicting the flow field in the carotid artery bifurcation and for understanding the relationship between hemodynamics and the initiation and progression of atherosclerosis. Clinical imaging modalities can be used to obtain geometry and blood flow data for developing subject-specific human carotid artery bifurcation models. We developed subject-specific computational fluid dynamics models of the human carotid bifurcation from magnetic resonance (MR) geometry data and phase contrast MR velocity data measured in vivo. Two simulations were conducted with identical geometry, flow rates, and fluid parameters: (1) Simulation 1 used in vivo measured velocity distributions as time-varying boundary conditions and (2) Simulation 2 used idealized fully-developed velocity profiles as boundary conditions. The position and extent of negative axial velocity regions (NAVRs) vary between the two simulations at any given point in time, and these regions vary temporally within each simulation. The combination of inlet velocity boundary conditions, geometry, and flow waveforms influences NAVRs. In particular, the combination of flow division and the location of the velocity peak with respect to individual carotid geometry landmarks (bifurcation apex position and the departure angle of the internal carotid) influences the size and location of these reversed flow zones. Average axial wall shear stress (WSS) distributions are qualitatively similar for the two simulations; however, instantaneous WSS values vary with the choice of velocity boundary conditions. By developing subject-specific simulations from in vivo measured geometry and flow data and varying the velocity boundary conditions in otherwise identical models, we isolated the effects of measured versus idealized velocity distributions on blood flow patterns. Choice of velocity distributions at boundary conditions is shown to influence pathophysiologically relevant flow patterns in the human carotid bifurcation. Although mean WSS distributions are qualitatively similar for measured and idealized inlet boundary conditions, instantaneous NAVRs differ and warrant imposing in vivo velocity boundary conditions in computational simulations. A simulation based on in vivo measured velocity distributions is preferred for modeling hemodynamics in subject-specific carotid artery bifurcation models when studying atherosclerosis initiation and development.
Three-Dimensional Computational Modeling of Subject-Specific Cerebrospinal Fluid Flow in the Subarachnoid Space
Authors: Gupta Sumeet , Soellinger Michaela , Boesiger Peter , Poulikakos Dimos , Kurtcuoglu Vartan
Published: December 2008

This study aims at investigating three-dimensional subject-specific cerebrospinal fluid (CSF) dynamics in the inferior cranial space, the superior spinal subarachnoid space (SAS), and the fourth cerebral ventricle using a combination of a finite-volume computational fluid dynamics (CFD) approach and magnetic resonance imaging (MRI) experiments. An anatomically accurate 3D model of the entire SAS of a healthy volunteer was reconstructed from high resolution T2 weighted MRI data. Subject-specific pulsatile velocity boundary conditions were imposed at planes in the pontine cistern, cerebellomedullary cistern, and in the spinal subarachnoid space. Velocimetric MRI was used to measure the velocity field at these boundaries. A constant pressure boundary condition was imposed at the interface between the aqueduct of Sylvius and the fourth ventricle. The morphology of the SAS with its complex trabecula structures was taken into account through a novel porous media model with anisotropic permeability. The governing equations were solved using finite-volume CFD. We observed a total pressure variation from −42Pato40Pa within one cardiac cycle in the investigated domain. Maximum CSF velocities of about 15cm∕s occurred in the inferior section of the aqueduct, 14cm∕s in the left foramen of Luschka, and 9cm∕s in the foramen of Magendie. Flow velocities in the right foramen of Luschka were found to be significantly lower than in the left, indicating three-dimensional brain asymmetries. The flow in the cerebellomedullary cistern was found to be relatively diffusive with a peak Reynolds number (Re)=72, while the flow in the pontine cistern was primarily convective with a peak Re=386. The net volumetric flow rate in the spinal canal was found to be negligible despite CSF oscillation with substantial amplitude with a maximum volumetric flow rate of 109ml∕min. The observed transient flow patterns indicate a compliant behavior of the cranial subarachnoid space. Still, the estimated deformations were small owing to the large parenchymal surface. We have integrated anatomic and velocimetric MRI data with computational fluid dynamics incorporating the porous SAS morphology for the subject-specific reconstruction of cerebrospinal fluid flow in the subarachnoid space. This model can be used as a basis for the development of computational tools, e.g., for the optimization of intrathecal drug delivery and computer-aided evaluation of cerebral pathologies such as syrinx development in syringomelia.
Slow-Time Changes in Human EMG Muscle Fatigue States Are Fully Represented in Movement Kinematics
Authors: Song Miao , Segala David B. , Dingwell Jonathan B. , Chelidze David
Published: December 2008

The ability to identify physiologic fatigue and related changes in kinematics can provide an important tool for diagnosing fatigue-related injuries. This study examined an exhaustive cycling task to demonstrate how changes in movement kinematics and variability reflect underlying changes in local muscle states. Motion kinematics data were used to construct fatigue features. Their multivariate analysis, based on smooth orthogonal decomposition, was used to reconstruct physiological fatigue. Two different features composed of (1) standard statistical metrics (SSM), which were a collection of standard long-time measures, and (2) phase space warping (PSW)–based metrics, which characterized short-time variations in the phase space trajectories, were considered. Movement kinematics and surface electromyography (EMG) signals were measured from the lower extremities of seven highly trained cyclists as they cycled to voluntary exhaustion on a stationary bicycle. Mean and median frequencies from the EMG time series were computed to measure the local fatigue dynamics of individual muscles independent of the SSM- and PSW-based features, which were extracted solely from the kinematics data. A nonlinear analysis of kinematic features was shown to be essential for capturing full multidimensional fatigue dynamics. A four-dimensional fatigue manifold identified using a nonlinear PSW-based analysis of kinematics data was shown to adequately predict all EMG-based individual muscle fatigue trends. While SSM-based analyses showed similar dominant global fatigue trends, they failed to capture individual muscle activities in a low-dimensional manifold. Therefore, the nonlinear PSW-based analysis of strictly kinematic time series data directly predicted all of the local muscle fatigue trends in a low-dimensional systemic fatigue trajectory. These results provide the first direct quantitative link between changes in muscle fatigue dynamics and resulting changes in movement kinematics.
Invariant-Based Anisotropic Constitutive Models of the Healthy and Aneurysmal Abdominal Aortic Wall
Authors: Basciano C. A. , Kleinstreuer C.
Published: December 2008

The arterial wall is a complex fiber-reinforced composite. Pathological conditions, such as aneurysms, significantly alter the mechanical response of the arterial wall, resulting in a loss of elasticity, enhanced anisotropy, and increased chances of mechanical failure. Invariant-based models of the healthy and aneurysmal abdominal aorta were constructed based on first principles and published experimental data with implementations for several numerical cases, as well as comparisons to current healthy and aneurysmal tissue data. Inherent limitations of a traditional invariant-based methodology are also discussed and compared to the models’ ability to accurately reproduce experimental trends. The models capture the nonlinear and anisotropic mechanical responses of the two arterial sections and make reasonable predictions regarding the effects of alterations in healthy and diseased tissue histology. Additionally, the new models exhibit convex and anisotropic monotonically increasing energy contours (suggesting numerical stability) but have potentially the inherent limitations of a covariant theoretical framework. Although the traditional invariant framework exhibits significant covariance, the invariant terms utilized in the new models exhibited limited covariance and are able to accurately reproduce experimental trends. A streamlined implementation is also possible for future numerical investigations of fluid-structure interactions in abdominal aortic aneurysms.
Nuclear Reprogramming in Cells
Authors: Gurdon J. B. , Melton D. A.
Published: December 2008

Nuclear reprogramming describes a switch in gene expression of one kind of cell to that of another unrelated cell type. Early studies in frog cloning provided some of the first experimental evidence for reprogramming. Subsequent procedures included mammalian somatic cell nuclear transfer, cell fusion, induction of pluripotency by ectopic gene expression, and direct reprogramming. Through these methods it becomes possible to derive one kind of specialized cell (such as a brain cell) from another, more accessible, tissue (such as skin) in the same individual. This has potential applications for cell replacement without the immunosuppression treatments that are required when cells are transferred between genetically different individuals. This article provides some background to this field, a discussion of mechanisms and efficiency, and comments on prospects for future nuclear reprogramming research.