bluuebunny/crossref_metadata_2025 huggingface dataset:
Association between Endothelial Function and Chronotropic Incompetence in Subjects with Chronic Heart Failure Receiving Optimal Medical Therapy
Authors: Vittorio Timothy J. , Lanier Gregg , Zolty Ronald , Sarswat Nitasha , Tseng Chi‐Hong , Colombo Paolo C. , Jorde Ulrich P.
Published: January 2010

Objective: Impairment of flow‐mediated, endothelium‐dependent vasodilatation (FMD) of the brachial artery identifies peripheral endothelial dysfunction in subjects with chronic congestive heart failure (CHF) and is associated with increased morbidity and mortality. To further elucidate the interaction of peripheral and central mechanisms in the syndrome of CHF, we examined the association between endothelial function and chronotropic incompetence, an emerging prognostic marker in CHF. Methods: Thirty subjects with stable New York Heart Association (NYHA) functional class II–III CHF were studied. A vascular ultrasound study was performed to measure brachial artery FMD. The percentage of age‐adjusted maximal predicted heart rate (MPHR) reached during cardiopulmonary exercise tolerance testing (CPETT) was used to assess the degree of chronotropic competence. All patients received ACE inhibitors and β‐adrenoceptor blockers. Results: Brachial artery FMD averaged 1.3 ± 2.4% and age‐adjusted % MPHR 74.1 ± 11.7%. FMD correlated with % MPHR among all patients (r = 0.60, P = 0.01). FMD and resting heart rate (RHR) did not significantly correlate (r = 0.13, P = 0.55). Conclusions: FMD, a measure of peripheral endothelial dysfunction, and % MPHR, a central determinant of cardiac output, are moderately correlated in heart failure patients receiving optimal medical therapy. Whether a cause‐effect relationship underlies this association remains to be investigated. (Echocardiography 2010;27:294‐299)
Sample Size Considerations for GEE Analyses of Three‐Level Cluster Randomized Trials
Authors: Teerenstra Steven , Lu Bing , Preisser John S. , van Achterberg Theo , Borm George F.
Published: January 2010

Summary Cluster randomized trials in health care may involve three instead of two levels, for instance, in trials where different interventions to improve quality of care are compared. In such trials, the intervention is implemented in health care units (“clusters”) and aims at changing the behavior of health care professionals working in this unit (“subjects”), while the effects are measured at the patient level (“evaluations”). Within the generalized estimating equations approach, we derive a sample size formula that accounts for two levels of clustering: that of subjects within clusters and that of evaluations within subjects. The formula reveals that sample size is inflated, relative to a design with completely independent evaluations, by a multiplicative term that can be expressed as a product of two variance inflation factors, one that quantifies the impact of within‐subject correlation of evaluations on the variance of subject‐level means and the other that quantifies the impact of the correlation between subject‐level means on the variance of the cluster means. Power levels as predicted by the sample size formula agreed well with the simulated power for more than 10 clusters in total, when data were analyzed using bias‐corrected estimating equations for the correlation parameters in combination with the model‐based covariance estimator or the sandwich estimator with a finite sample correction.
Simplified Bayesian Sensitivity Analysis for Mismeasured and Unobserved Confounders
Authors: Gustafson P. , McCandless L. C. , Levy A. R. , Richardson S.
Published: January 2010

SummaryWe examine situations where interest lies in the conditional association between outcome and exposure variables, given potential confounding variables. Concern arises that some potential confounders may not be measured accurately, whereas others may not be measured at all. Some form of sensitivity analysis might be employed, to assess how this limitation in available data impacts inference. A Bayesian approach to sensitivity analysis is straightforward in concept: a prior distribution is formed to encapsulate plausible relationships between unobserved and observed variables, and posterior inference about the conditional exposure–disease relationship then follows. In practice, though, it can be challenging to form such a prior distribution in both a realistic and simple manner. Moreover, it can be difficult to develop an attendant Markov chain Monte Carlo (MCMC) algorithm that will work effectively on a posterior distribution arising from a highly nonidentified model. In this article, a simple prior distribution for acknowledging both poorly measured and unmeasured confounding variables is developed. It requires that only a small number of hyperparameters be set by the user. Moreover, a particular computational approach for posterior inference is developed, because application of MCMC in a standard manner is seen to be ineffective in this problem.
Paranucleospora theridion n. gen., n. sp. (Microsporidia, Enterocytozoonidae) with a Life Cycle in the Salmon Louse (Lepeophtheirus salmonis, Copepoda) and Atlantic Salmon (Salmo salar)
Authors: NYLUND STIAN , NYLUND ARE , WATANABE KUNINORI , ARNESEN CARL E. , KARLSBAKK EGIL
Published: January 2010

ABSTRACT. Paranucleospora theridion n. gen, n. sp., infecting both Atlantic salmon (Salmo salar) and its copepod parasite Lepeophtheirus salmonis is described. The microsporidian exhibits nuclei in diplokaryotic arrangement during all known life‐cycle stages in salmon, but only in the merogonal stages and early sporogonal stage in salmon lice. All developmental stages of P. theridion are in direct contact with the host cell cytoplasm or nucleoplasm. In salmon, two developmental cycles were observed, producing spores in the cytoplasm of phagocytes or epidermal cells (Cycle‐I) and in the nuclei of epidermal cells (Cycle‐II), respectively. Cycle‐I spores are small and thin walled with a short polar tube, and are believed to be autoinfective. The larger oval intranuclear Cycle‐II spores have a thick endospore and a longer polar tube, and are probably responsible for transmission from salmon to L. salmonis. Parasite development in the salmon louse occurs in several different cell types that may be extremely hypertrophied due to P. theridion proliferation. Diplokaryotic merogony precedes monokaryotic sporogony. The rounded spores produced are comparable to the intranuclear spores in the salmon in most aspects, and likely transmit the infection to salmon. Phylogenetic analysis of P. theridion partial rDNA sequences place the parasite in a position between Nucleospora salmonis and Enterocytozoon bieneusi. Based on characteristics of the morphology, unique development involving a vertebrate fish as well as a crustacean ectoparasite host, and the results of the phylogenetic analyses it is suggested that P. theridion should be given status as a new species in a new genus.
A New Entodiniomorphid Ciliate, Troglocorys cava n. g., n. sp., from the Wild Eastern Chimpanzee (Pan troglodytes schweinfurthii) from Uganda
Authors: TOKIWA TOSHIHIRO , MODRÝ DAVID , ITO AKIRA , POMAJBÍKOVÁ KATEŘINA , PETRŽELKOVÁ KLÁRA J. , IMAI SOICHI
Published: January 2010

ABSTRACT. Troglocorys cava n. g., n. sp. is described from the feces of wild eastern chimpanzee, Pan troglodytes schweinfurthii, in Uganda. This new species has a spherical body with a frontal lobe, a long vestibulum, a cytoproct located at the posterior dorsal side of the body, an ovoid macronucleus, a contractile vacuole near the cytoproct, and a large concavity on the left surface of the body. Buccal ciliature is non‐retractable and consists of three ciliary zones: an adoral zone surrounding the vestibular opening, a dorso‐adoral zone extending transversely at the basis of the frontal lobe, and a vestibular zone longitudinally extending in a gently spiral curve to line the surface of the vestibulum. Two non‐retractable somatic ciliary zones comprise arches over the body surface: a short dorsal ciliary arch extending transversely at the basis of the frontal lobe and a wide C‐shaped left ciliary arch in the left concavity. Because of the presence of three ciliary zones in the non‐retractable buccal ciliature, the present genus might be a member of the family Blepharocorythidae, but the large left concavity and the C‐shaped left ciliary arch are unique, such structures have never been described from other blepharocorythids.
The Implementation of Intranasal Fentanyl for Children in a Mixed Adult and Pediatric Emergency Department Reduces Time to Analgesic Administration
Authors: Holdgate Anna , Cao Anthony , Lo Ka Mei
Published: January 2010

ACADEMIC EMERGENCY MEDICINE 2010; 17:1–4 © 2010 by the Society for Academic Emergency Medicine

Objectives:  The objective was to determine whether the introduction of intranasal (IN) fentanyl for children with acute pain would reduce the time to analgesic administration in a mixed adult and pediatric emergency department (ED).

Methods:  A protocol for IN fentanyl (1.5 μg/kg) for children age 1–15 years presenting with acute pain was introduced to the department. All children who received intravenous (IV) morphine in the 7 months prior to the introduction of the protocol and either IV morphine or IN fentanyl in the 7 months after the introduction of the protocol were identified from drug registers. Time to analgesic administration, time to see a doctor, and the ages of patients were compared between the periods before and after the introduction of IN fentanyl.

Results:  Following implementation, 81 patients received IN fentanyl and 37 received IV morphine, compared to 63 patients receiving morphine in the previous 7 months. The median time to analgesic administration for IN fentanyl was significantly shorter than for morphine (32 minutes vs. 63 minutes, p = 0.001). Children receiving fentanyl were significantly younger than those receiving morphine (median = 8.5 years vs. 12 years, p < 0.001).

Conclusions:  This study demonstrates that children treated with IN fentanyl received analgesic medication faster than those treated with IV morphine in a mixed ED. Younger children were more likely to receive opioid analgesia following the introduction of fentanyl.
Chemical Agent Simulant Release from Clothing Following Vapor Exposure
Authors: Feldman Robert J.
Published: January 2010

ACADEMIC EMERGENCY MEDICINE 2010; 17:1–4 © 2010 by the Society for Academic Emergency Medicine

Objectives:  Most ambulatory victims of a terrorist chemical attack will have exposure to vapor only. The study objective was to measure the duration of chemical vapor release from various types of clothing.

Methods:  A chemical agent was simulated using methyl salicylate (MeS), which has similar physical properties to sulfur mustard and was the agent used in the U.S. Army’s Man‐In‐Simulant Test (MIST). Vapor concentration was measured with a Smiths Detection Advanced Portable Detector (APD)‐2000 unit. The clothing items were exposed to vapor for 1 hour in a sealed cabinet; vapor concentration was measured at the start and end of each exposure. Clothing was then removed and assessed every 5 minutes with the APD‐2000, using a uniform sweep pattern, until readings remained 0.

Results:  Concentration and duration of vapor release from clothing varied with clothing composition and construction. Lightweight cotton shirts and jeans had the least trapped vapor; down outerwear, the most. Vapor concentration near the clothing often increased for several minutes after the clothing was removed from the contaminated environment. Compression of thick outerwear released additional vapor. Mean times to reach 0 ranged from 7 minutes for jeans to 42 minutes for down jackets.

Conclusions:  This simulation model of chemical vapor release demonstrates persistent presence of simulant vapor over time. This implies that chemical vapor may be released from the victims’ clothing after they are evacuated from the site of exposure, resulting in additional exposure of victims and emergency responders. Insulated outerwear can release additional vapor when handled. If a patient has just moved to a vapor screening point, immediate assessment before additional vapor can be released from the clothing can lead to a false‐negative assessment of contamination.
The Effect of Vertebral Numerical Variation on Anatomical Stature Estimates
Authors: Raxter Michelle H. , Ruff Christopher B.
Published: January 2010

Abstract:  Most humans possess 24 presacral vertebrae composed of seven cervicals, 12 thoracics, and five lumbars. However, variation from this standard pattern exists. The purpose of this study was to test the effect of congenital vertebral numerical variation on anatomical stature estimates and to recommend appropriate procedures when such variation occurs. Our sample consists of 41 individuals with unusual vertebral count patterns and known cadaveric statures from the Smithsonian’s Terry Collection. Raxter et al. published a revised Fully anatomical technique in 2006 and we used this to estimate living stature. Based on our results, we recommend using the standard anatomical technique to reconstruct stature, regardless of vertebral pattern. However, when an individual possesses six sacral segments together with a normal number of presacral vertebrae, we recommend the addition of a slight correction factor of 1.3 cm or 0.8% of estimated stature.
New Formulas to Estimate Age at Death in Maya Populations Using Histomorphological Changes in the Fourth Human Rib*
Authors: Pavón Margarita Valencia , Cucina Andrea , Tiesler Vera
Published: January 2010

Abstract: This study develops new histomorphological algorithms for Maya populations’ human ribs and tests the applicability of published algorithms. Thin sections from the fourth rib of 36 individuals of known age were analyzed under polarized light microscopy. Osteon population density (OPD, the concentration of intact and fragmented osteons per mm2), cortical area (CA), and osteon size (OS) were recorded. Seven algorithms were calculated, using all combinations of variables, and compared to the performance of published formulas. The OPD‐based formulas deviate from the known age 8.7 years on average, while those from OS and CA deviate between 10.7 and 12.8 years. In comparison, our OPD‐based algorithms perform better than the one by Stout and Paine and much better than Cho et al. In conclusion, algorithms should be developed using OPD for different ethnic groups; although Stout and Paine’s can be used for Maya and maybe Mesoamerican individuals.
Psychiatric Disorders (Axis I and Axis II) and Self‐Immolation: A Case–Control Study from Iran*
Authors: Ahmadi Alireza , Mohammadi Reza , Schwebel David C. , Yeganeh Naser , Hassanzadeh Mehdi , Bazargan‐Hejazi Shahrzad
Published: January 2010

Abstract:  The objective of this study was to investigate preexisting psychiatric disorders in self‐immolation patients. In a case–control study, 30 consecutive cases of deliberate self‐inflicted burns, admitted to the regional burn center, were compared with 30 controls. Mental disorders were assessed via detailed clinical interview. Descriptive data revealed that 67% of self‐immolation patients had adjustment disorder (all female), 10% drug and alcohol abuse/dependence (all male), 7% dysthymia, 3% major depression, 3% anorexia nervosa, 3% primary insomnia, 7% borderline personality disorder (50% male), 7% depressive personality disorder (100% female), and 3% antisocial personality disorder. In bivariate comparisons, adjustment disorders emerged as related to risk of self‐immolation (odds ratio = 13.00). This study suggests that adjustment disorder is a risk factor for self‐immolation. As a result, it has been suggested that increasing education about problem‐solving approaches, and coping skills for females and at‐risk groups are appropriate prevention programs and strategies in Iranian communities.
Motor Vehicle Occupants, Neck Injuries, and Seat Belt Utilization: A 5‐Year Study of Fatalities in New York City
Authors: Sgarlato Anthony , DeRoux Stephen J
Published: January 2010

Abstract:  Despite the implementation of numerous safety devices in automobiles, vehicular occupant fatalities following collisions remain common. We reviewed all fatalities of vehicular occupants in New York City over a 5‐year period on whom autopsies were performed (437) to determine the incidence of neck injuries and correlate them with seat belt utilization; 26.5% had neck injuries (mild to severe) and only 10.3% of these occupants were confirmed to be wearing seatbelts. Of those that had documentation of seat belt utilization there were twice as many neck injuries in the unbelted group. We highlight two cases of submarining with severe neck injuries that were related to automatic 2‐point shoulder harness restraints without engagement of the lap belt.
Effect of food deprivation on the ambulatory movement of the Colorado potato beetle, Leptinotarsa decemlineata
Authors: Gui Lian‐You , Boiteau G.
Published: January 2010

Modification of dispersal behaviour is a common response of insects to food and water deprivation. The literature suggests that different insects respond with different strategies: changing walking parameters, switching dispersal mode (walking to flight or vice versa), or changing the host searching path. The goal of this study was to add to the limited literature on the subject by investigating, whether the walking parameters of adult male Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), change in response to food and water deprivation. Observations on the distance walked, the travel speed, and the frequency of walking bouts were carried out in laboratory arenas using motion monitoring equipment. Summer and overwintered beetles were exposed to short starvation periods (2, 4, 8, 24 h) and two ranges of long starvation periods (1, 2, 4, 8 days and 1, 2, 4, 8, 16, and 32 days). Only the longest food deprivation periods of 16 and 32 days significantly reduced the walking distance, speed, and frequency of walking bouts of summer beetles. No changes were observed with overwintered beetles. The tolerance of the beetles without access to water to the different periods of food deprivation was similar to that for beetles with water except after a starvation period of 32 days, when the travel speed of summer beetles was significantly reduced by 33%. The absence of increased walking parameters found in this study and earlier observations of increased flight frequency suggest that the strategy of summer beetles will be to change the dispersal mode from walking to flight and/or to change the walking host searching path. The same results of this study and earlier observations of a decrease in the mean frequency of daily flights suggest that the strategy of overwintered L. decemlineata, exposed to food deprivation, will be to change the host search walking path rather than the walking parameters themselves.
Nosema pyrausta and Cry1Ab‐incorporated diet led to decreased survival and developmental delays in European corn borer
Authors: Lopez Miriam D. , Sumerford Douglas V. , Lewis Leslie C.
Published: January 2010

The high dose/refuge strategy for delaying evolution of resistance to Bt maize [Zea mays L. (Poaceae)] relies on random mating between resistant European corn borers, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), and susceptible O. nubilalis from the refuge. However, differences in developmental rate caused by feeding on Bt maize, or infection with the microsporidium Nosema pyrausta Paillot (Microsporida: Nosematidae) may result in assortative mating. Developmental delays and mortality caused by infection with N. pyrausta and feeding on Bt maize were quantified alone and in combination in Cry1Ab‐resistant and susceptible O. nubilalis. Feeding on Cry1Ab‐incorporated diet significantly increased number of days from hatch to pupation and decreased survival in the resistant population. Infection with N. pyrausta increased mortality and lengthened development in both the resistant and susceptible populations. The combination of Cry1Ab‐incorporated diet and infection with N. pyrausta in resistant O. nubilalis lengthened development and increased mortality to a greater extent than either factor alone. Greater larval delays of resistant O. nubilalis feeding on Bt maize could lead to temporal isolation from adults emerging from refuge maize. The resulting assortative mating would hasten the evolution of resistance. Developmental delays caused by infection with N. pyrausta may increase the likelihood of mating between resistant and infected susceptible adults emerging from refuge maize, producing infected offspring that are also more susceptible to Bt maize.
Direct and correlated responses to chill‐coma recovery selection in Drosophila buzzatii
Authors: Bertoli Carlos I. , Scannapieco Alejandra C. , Sambucetti Pablo , Norry Fabian M.
Published: January 2010

Chill‐coma recovery (CCR) is an important trait for thermal adaptation in insects. Multiple phenotypes could be affected by selection on CCR if the trait is genetically correlated with other adaptive traits. To test for heritable (co‐)variation in CCR, we examined direct and correlated responses to bi‐directional selection on CCR. Drosophila buzzatii Patterson & Wheeler (Diptera: Drosophilidae) was artificially selected for decreased and increased recovery time following exposure to 0 °C. After 18 selected generations, the selection response in CCR was significant but qualitatively asymmetric, with replicated lines for slow CCR showing the highest response. Knockdown resistance to high temperature was not affected by CCR selection. Starvation resistance in the adult fly showed no clear pattern of correlated responses to CCR selection. Selection on CCR had no impact on developmental time and body size. Chill‐coma recovery shows no apparent genetic trade‐offs with any of the multiple traits included in this study. These results are largely consistent with recent studies on clines in D. buzzatii, which showed that CCR is not across‐population correlated with other clinally varying traits of thermal adaptation. Cold adaptation may evolve toward increased cold resistance independent of upper thermal limits.
Evidence of active or passive downwind dispersal in mark–release–recapture of moths
Authors: Guichard S. , Kriticos D. J. , Leriche A. , Worner S. P. , Kean J. M. , Suckling D. M.
Published: January 2010

Modelling moth dispersal in relation to wind direction and strength could greatly enhance the role of pheromone traps in biosecurity and pest management applications. Anemotaxis theory, which describes moth behaviour in the presence of a pheromone plume and is used as a framework for such models. Currently, however, that theory includes only three components: upwind, zigzagging, and sideways casting behaviour. We test anemotaxis theory by analysing the data from a series of mark–release–recapture experiments where the wind direction was known and the insects were trapped using an irregular grid of pheromone traps. The trapping results provide evidence of a downwind component to the flight patterns of the released insects. This active or passive downwind dispersal is likely to be an appetitive behaviour, occurring prior to the elicitation of pheromone‐oriented flight patterns (pheromone anemotaxis). Given the potential for significant displacement during downwind dispersal, this component will have impact on final trap captures and should be considered when constructing moth dispersal models.
Chagas’ disease: an update on immune mechanisms and therapeutic strategies
Authors: Boscardin Silvia Beatriz , Torrecilhas Ana Claudia Troccoli , Manarin Romina , Revelli Silvia , Rey Elena Gonzalez , Tonelli Renata Rosito , Silber Ariel Mariano
Published: January 2010

Introduction

Chagas’ disease

Chemotherapy

Immune response in experimental T. cruzi infection

Immune response in human beings infected with T. cruzi

Immune response in the treatment of chagasic infection

The need for new therapeutic alternatives for Chagas’ disease

Conclusions

The final decade of the 20th century was marked by an alarming resurgence in infectious diseases caused by tropical parasites belonging to the kinetoplastid protozoan order. Among the pathogenic trypanosomatids, some species are of particular interest due to their medical importance. These species include the agent responsible for Chagas’ disease, Trypanosoma cruzi. Approximately 8 to 10 million people are infected in the Americas, and approximately 40 million are at risk. In the present review, we discuss in detail the immune mechanisms elicited during infection by T. cruzi and the effects of chemotherapy in controlling parasite proliferation and on the host immune system.
Basic mechanisms of neurodegeneration: a critical update
Authors: Jellinger Kurt A.
Published: January 2010

Introduction

Protein aggregation

Oxidative injury

Impaired bioenergetics and mitochondrial dysfunction

Fragmentation of neuronal Golgi apparatus

Disruption of cellular/axonal transport

Dysfunction of neurotrophins

‘Neuroinflammatory’ processes

The final pathway: multifaceted neuronal death

Cell death cascades in major NDDs

Acknowledgements

Neurodegenerative diseases are characterized by progressive dysfunction of specific populations of neurons, determining clinical presentation. Neuronal loss is associated with extra and intracellular accumulation of misfolded proteins, the hallmarks of many neurodegenerative proteinopathies. Major basic processes include abnormal protein dynamics due to deficiency of the ubiquitin–proteosome–autophagy system, oxidative stress and free radical formation, mitochondrial dysfunction, impaired bioenergetics, dysfunction of neurotrophins, ‘neuroinflammatory’ processes and (secondary) disruptions of neuronal Golgi apparatus and axonal transport. These interrelated mechanisms lead to programmed cell death is a long run over many years. Neurodegenerative disorders are classified according to known genetic mechanisms or to major components of protein deposits, but recent studies showed both overlap and intraindividual diversities between different phenotypes. Synergistic mechanisms between pathological proteins suggest common pathogenic mechanisms. Animal models and other studies have provided insight into the basic neurodegeneration and cell death programs, offering new ways for future prevention/treatment strategies.
Spatial scaling and transition in pneumatophore arthropod communities
Authors: Procheş Şerban , Warren Marié , McGeoch Melodie A. , Marshall David J.
Published: January 2010

Although most ecological variables are scale‐dependent, few studies cover a broad range of spatial scales. Here, we consider South African mangrove pneumatophore arthropod communities (mites, crustaceans and insects), across seven spatial scales (from 10 cm to 100 km). We plot spatial autocorrelation in individual species, evaluate if resource and habitat availability determine spatial patterning, and identify the scales of community transition. Spatial autocorrelation in most ecological variables decreased with increasing spatial scale, with notable exceptions for the larger scales. Negative abundance autocorrelation was stronger at 10 km than at 100 km for common species, while the opposite was true for rare species. Spatial autocorrelation in species richness decreased from 1 m (strong positive) to 10 km (strong negative), but was not significant at the 100 km scale. These patterns reflect the patchy distribution of pneumatophores within mangrove forests, that of the forests along the coast, and the poor dispersal abilities of most of the arthropods sampled, in a highly dynamic environment. Although resource and habitat availability exhibited a similar autocorrelation pattern to that of the community, the total mass of pneumatophores did not appear to be an important determinant of community structure. Variations in the abundance of common species, as well as the restricted distribution of rare species caused assemblage structure to change gradually with increasing distance from 10 cm to 100 km, but only marginally from 10 to 100 km. We highlight the need for cross‐scale studies in bridging the gap between two key ecological concepts: potential ecological niche and realized geographic range.
Integrating physiology, population dynamics and climate to make multi‐scale predictions for the spread of an invasive insect: the Argentine ant at Haleakala National Park, Hawaii
Authors: Hartley Stephen , Krushelnycky Paul D. , Lester Philip J.
Published: January 2010

Mechanistic models for predicting species’ distribution patterns present particular advantages and challenges relative to models developed from statistical correlations between distribution and climate. They can be especially useful for predicting the range of invasive species whose distribution has not yet reached equilibrium. Here, we illustrate how a physiological model of development for the invasive Argentine ant can be connected to differences in micro‐site suitability, population dynamics and climatic gradients; processes operating at quite different spatial scales. Our study is located in the subalpine shrubland of Haleakala National Park, Hawaii, where the spread of Argentine ants Linepithema humile has been documented for the past twenty‐five years. We report four main results. First, at a microsite level, the accumulation of degree‐days recorded in potential ant nest sites under bare ground or rocks was significantly greater than under a groundcover of grassy vegetation. Second, annual degree‐days measured where population boundaries have not expanded (456–521 degree‐days), were just above the developmental requirements identified from earlier laboratory studies (445 degree‐days above 15.9°C). Third, rates of population expansion showed a strong linear relationship with annual degree‐days. Finally, an empirical relationship between soil degree‐days and climate variables mapped at a broader scale predicts the potential for future range expansion of Argentine ants at Haleakala, particularly to the west of the lower colony and the east of the upper colony. Variation in the availability of suitable microsites, driven by changes in vegetation cover and ultimately climate, provide a hierarchical understanding of the distribution of Argentine ants close to their cold‐wet limit of climatic tolerances. We conclude that the integration of physiology, population dynamics and climate mapping holds much promise for making more robust predictions about the potential spread of invasive species.
Linking habitat use to range expansion rates in fragmented landscapes: a metapopulation approach
Authors: Wilson Robert J. , Davies Zoe G. , Thomas Chris D.
Published: January 2010

Temperature increases because of climate change are expected to cause expansions at the high latitude margins of species distributions, but, in practice, fragmented landscapes act as barriers to colonization for most species. Understanding how species distributions will shift in response to climate change therefore requires techniques that incorporate the combined effects of climate and landscape‐scale habitat availability on colonization rates. We use a metapopulation model (Incidence Function Model, IFM) to test effects of fine‐scale habitat use on patterns and rates of range expansion by the butterflyHesperia comma. At its northern range margin in Britain, this species has increased its breadth of microhabitat use because of climate warming, leading to increased colonization rates. We validated the IFM by reconstructing expansions in five habitat networks between 1982 and 2000, before using it to predict metapopulation dynamics over 100 yr, for three scenarios based on observed changes to habitat use. We define the scenarios as “cold‐world” (only hot, south‐facing 150–250° hillsides are deemed warm enough), “warm‐world” in which 100–300° hillsides can be populated, and “hot‐world”, where the background climate is warm enough to enable use of all aspects (as increasingly observed). In the simulations, increased habitat availability in the hot‐world scenario led to faster range expansion rates, and to long‐term differences in distribution size and pattern. Thus, fine‐scale changes in the distribution of suitable microclimates led to landscape‐scale changes in population size and colonization rate, resulting in coarse‐scale changes to the species distribution. Despite use of a wider range of habitats associated with climate change,H. commais still expected to occupy a small fraction of available habitat in 100 yr. The research shows that metapopulation models represent a potential framework to identify barriers to range expansion, and to predict the effects of environmental change or conservation interventions on species distributions and persistence.
From complex spatial dynamics to simple Markov chain models: do predators and prey leave footprints?
Authors: Nachman Gösta , Borregaard Michael K.
Published: January 2010

In this paper we present a concept for using presence–absence data to recover information on the population dynamics of predator–prey systems. We use a highly complex and spatially explicit simulation model of a predator–prey mite system to generate simple presence–absence data: the number of patches with both prey and predators, with prey only, with predators only, and with neither species, along with the number of patches that change from one state to another in each time step. The average number of patches in the four states, as well as the average transition probabilities from one state to another, are then depicted in a state transition diagram, constituting the “footprints” of the underlying population dynamics. We investigate to what extent changes in the population processes modeled in the complex simulation (i.e. the predator's functional response and the dispersal rates of both species) are reflected by different footprints

The transition probabilities can be used to forecast the expected fate of a system given its current state. However, the transition probabilities in the modeled system depend on the number of patches in each state. We develop a model for the dependence of transition probabilities on state variables, and combine this information in a Markov chain transition matrix model. Finally, we use this extended model to predict the long‐term dynamics of the system and to reveal its asymptotic steady state properties.
Validation of self‐reported recreational exercise in pregnant women in the Norwegian Mother and Child Cohort Study
Authors: Brantsæter A. L. , Owe K. M. , Haugen M. , Alexander J. , Meltzer H. M. , Longnecker M. P.
Published: January 2010

We compared the self‐reported frequency of recreational exercise and corresponding metabolic equivalent (MET)‐minutes with physical activity measured with a position and motion sensor in pregnant women. One hundred and twelve women in the Norwegian Mother and Child Cohort Study (MoBa) completed questions about weekly participation in recreational exercise by week 17 of pregnancy and participated in the validation study around week 20. Data from a validated motion sensor (ActiReg®) that measures physical activity and total energy expenditure (TEE) served as the “gold standard.” Self‐reported recreational exercise was compared with the following ActiReg®‐based measures: physical activity energy expenditure (PAEE), minutes of vigorous physical activity (VPA), physical activity level (PAL) and TEE. Pearson's correlations between self‐reported weekly exercise and the objectively assessed variables were: rPAEE=0.26, rVPA=0.32, rPAL=0.30 (all P<0.01) and rTEE=0.17 (P=0.07). The partial correlation coefficients between the questionnaire responses and the ActiReg® measurements were similar after adjusting for parity, body mass index, education, age, height and smoking, but rTEE increased (r=0.27, P<0.01). We observed significant positive associations between self‐reported exercise activities and motion sensor measurements of physical activity, indicating that the questions used for exercise assessment in MoBa may be useful for ranking pregnant women according to the recreational exercise level.
Sports and leisure‐time physical activity in pregnancy and birth weight: a population‐based study
Authors: Hegaard H. K. , Petersson K. , Hedegaard M. , Ottesen B. , Dykes A. K. , Henriksen T. B. , Damm P.
Published: January 2010

We examined the association between sports and other leisure‐time physical activities during pregnancy and birth weight of babies born after 37 completed weeks of gestation. All Danish‐speaking pregnant women attending routine antenatal care at the Department of Obstetrics, Aarhus University Hospital, Denmark, from August 1989 to September 1991 were invited to participate in the study. A total of 4458 healthy women who delivered after 37 completed gestational weeks participated in this study. The associations between sports (0, 1–2, 3+ h/week) or leisure‐time physical activity (sedentary, light, and moderate to heavy) and birth weight were examined by linear and logistic regression and adjusted for potential confounding factors such as smoking, parity, schooling, pre‐pregnancy body mass index and gestational age. The results showed that pregnant women who practiced sports or were moderate to heavy leisure‐time physical active during the early second or the early third trimester gave birth to infants with a similar birth weight as inactive women. The proportion of newborns with a low (<2500 g) or a high birth weight (≥4500 g) was also unchanged. In conclusion, in this large population‐based study, we found no association between sports and leisure‐time physical activity and low‐birth weight, high‐birth weight, or average‐birth weight.
Age‐friendly buses? A comparison of reported barriers and facilitators to bus use for younger and older adults
Authors: Broome Kieran , Nalder Emily , Worrall Linda , Boldy Duncan
Published: January 2010

Aim:  To determine whether older people reported and prioritised different barriers and facilitators to bus use than younger people.

Method:  The Nominal Group Technique was used with 301 participants (231 older, 70 younger) to elicit reported barriers and facilitators to bus use. Categories were developed using qualitative content analysis and comparisons of categories and priorities were made.

Results:  Driver friendliness, ease of entry/exit and information useability were prioritised barriers and facilitators for older people. In contrast, younger participants prioritised bus punctuality, signage clarity, information provision at bus stops, bus service availability and parking facilities at the bus stop. Some similarities between older and younger adults were noted relating to convenience and bus scheduling.

Conclusions:  Older and younger adults have specific requirements for public transport systems which should be addressed in order to promote useable transport for all.
Estrogen‐related receptor α and PGC‐1‐related coactivator constitute a novel complex mediating the biogenesis of functional mitochondria
Authors: Mirebeau‐Prunier Delphine , Le Pennec Soazig , Jacques Caroline , Gueguen Naig , Poirier Julie , Malthiery Yves , Savagner Frédérique
Published: January 2010

Mitochondrial biogenesis, which depends on nuclear as well as mitochondrial genes, occurs in response to increased cellular ATP demand. The nuclear transcriptional factors, estrogen‐related receptor α (ERRα) and nuclear respiratory factors 1 and 2, are associated with the coordination of the transcriptional machinery governing mitochondrial biogenesis, whereas coactivators of the peroxisome proliferator‐activated receptor γ coactivator‐1 (PGC‐1) family serve as mediators between the environment and this machinery. In the context of proliferating cells, PGC‐1‐related coactivator (PRC) is a member of the PGC‐1 family, which is known to act in partnership with nuclear respiratory factors, but no functional interference between PRC and ERRα has been described so far. We explored three thyroid cell lines, FTC‐133, XTC.UC1 and RO 82 W‐1, each characterized by a different mitochondrial content, and studied their behavior towards PRC and ERRα in terms of respiratory efficiency. Overexpression of PRC and ERRα led to increased respiratory chain capacity and mitochondrial mass. The inhibition of ERRα decreased cell growth and respiratory chain capacity in all three cell lines. However, the inhibition of PRC and ERRα produced a greater effect in the oxidative cell model, decreasing the mitochondrial mass and the phosphorylating respiration, whereas the nonphosphorylating respiration remained unchanged. We therefore hypothesize that the ERRα–PRC complex plays a role in arresting the cell cycle through the regulation of oxidative phosphorylation in oxidative cells, and through some other pathway in glycolytic cells.
Slow deactivation of ribulose 1,5‐bisphosphate carboxylase/oxygenase elucidated by mathematical models
Authors: Witzel Franziska , Götze Jan , Ebenhöh Oliver
Published: January 2010

Ribulose 1,5‐bisphosphate carboxylase/oxygenase (RuBisCO) is the key enzyme of the Calvin cycle, catalyzing the fixation of inorganic carbon dioxide to organic sugars. Unlike most enzymes, RuBisCO is extremely slow, substrate unspecific, and catalyzes undesired side‐reactions, which are considered to be responsible for the slow deactivation observed in vitro, a phenomenon known as fallover. Despite the fact that amino acid sequences and the 3D structures of RuBisCO from a variety of species are known, the precise molecular mechanisms for the various side reactions are still unclear. In the present study, we investigate the kinetic properties of RuBisCO using mathematical models. Initially, we formulate a minimal model that quantitatively reflects the kinetic behavior of RuBisCOs from different organisms. By relating rate parameters for single molecular steps to experimentally determined Km and Vmax values, we can examine mechanistic differences among species. The minimal model further demonstrates that two inhibitor producing side reactions are sufficient to describe experimentally determined fallover kinetics. To explain the observed kinetics of the limited capacity of RuBisCO to accept xylulose 1,5‐bisphosphate as substrate, the inclusion of other side reactions is necessary. Our model results suggest a yet undescribed alternative enolization mechanism that is supported by the molecular structure. Taken together, the presented models serve as a theoretical framework to explain a wide range of observed kinetic properties of RuBisCOs derived from a variety of species. Thus, we can support hypotheses about molecular mechanisms and can systematically compare enzymes from different origins.
Molecular Analysis of Legume Nodule Development and Autoregulation
Authors: Ferguson Brett J. , Indrasumunar Arief , Hayashi Satomi , Lin Meng‐Han , Lin Yu‐Hsiang , Reid Dugald E. , Gresshoff Peter M.
Published: January 2010

Legumes are highly important food, feed and biofuel crops. With few exceptions, they can enter into an intricate symbiotic relationship with specific soil bacteria called rhizobia. This interaction results in the formation of a new root organ called the nodule in which the rhizobia convert atmospheric nitrogen gas into forms of nitrogen that are useable by the plant. The plant tightly controls the number of nodules it forms, via a complex root‐to‐shoot‐to‐root signaling loop called autoregulation of nodulation (AON). This regulatory process involves peptide hormones, receptor kinases and small metabolites. Using modern genetic and genomic techniques, many of the components required for nodule formation and AON have now been isolated. This review addresses these recent findings, presents detailed models of the nodulation and AON processes, and identifies gaps in our understanding of these process that have yet to be fully explained.
Regulation of Vascular Development by CLE Peptide‐receptor Systems
Authors: Hirakawa Yuki , Kondo Yuki , Fukuda Hiroo
Published: January 2010

Cell division and differentiation of stem cells are controlled by non‐cell‐autonomous signals in higher organisms. The plant vascular meristem is a stem‐cell tissue comprising procambial cells that produce xylem cells on one side and phloem cells on the other side. Recent studies have revealed that TDIF (tracheary element differentiation inhibitory factor)/CLE41/CLE44 peptide signal controls the procambial cell fate in a non‐cell‐autonomous manner. TDIF produced in and secreted from phloem cells is perceived by TDR/PXY, a leucine‐rich repeat receptor kinase located in the plasma membrane of procambial cells. This signal suppresses xylem cell differentiation of procambial cells and promotes their proliferation. In addition to TDIF, some other CLE peptides play roles in vascular development. Here, we summarize recent advances in CLE signaling governing vascular development.
High-energy emission as a test of the prior emission model for gamma-ray burst afterglows
Authors: Murase Kohta , Toma Kenji , Yamazaki Ryo , Nagataki Shigehiro , Ioka Kunihito
Published: January 2010

We study high-energy gamma-ray afterglow emission from gamma-ray bursts (GRBs) in the prior emission model, which is proposed to explain the plateau phase of the X-ray afterglow. This model predicts the high-energy gamma-ray emission when the prompt GRB photons from the main flow are up-scattered by relativistic electrons accelerated at the external shock due to the prior flow. The expected spectrum has the peak of ∼10–100 GeV at around the end time of the plateau phase for typical GRBs, and high-energy gamma-rays from nearby and/or energetic GRBs can be detected by the current and future Cherenkov telescopes such as MAGIC, VERITAS, CTA and possibly Fermi. Multiwavelength observations by ground-based optical telescopes as well as Fermi and/or Swift satellites are important to constrain the model. Such external inverse-Compton emission may even lead to GeV–TeV gamma-ray signals with the delay time of ∼10–100 s, only if the plateau phase is short lived.
Plume Detachment and Recession Times in Fractured Rock
Authors: West Michael R. , Kueper Bernard H.
Published: January 2010

The influence of source zone concentration reduction on solute plume detachment and recession times in fractured rock was investigated using new semianalytical solutions to transient solute transport in the presence of advection, dispersion, sorption, matrix diffusion, and first‐order decay. Novel aspects of these solutions are: (1) the source zone concentration behavior is simulated using a constant concentration with the option for either an instantaneous reduction to zero concentration or an exponentially decaying source zone concentration initiated at some time (t*) after the source is introduced, and (2) different biodegradation rates in the fracture and rock matrix. These solutions were applied for sandstone bedrock and revealed that biodegradation in the matrix, not the fracture, may be the most significant attenuation mechanism and therefore may dictate remediation time scales. Also, instantaneous and complete source concentration reduction in aged plumes may not be beneficial with respect to plume response because back‐diffusion can sustain plume migration for long periods of time. Moderate source zone concentration reduction has a similar impact on the rate of advance of the leading edge of the plume as aggressive concentration reduction. If the source zone concentration reduction half‐life is less than the plume decay half‐life, then volatile organic compound (VOC) mass sequestered in the rock matrix will ultimately dictate plume persistence and not the presence of the source zone.