bluuebunny/crossref_metadata_2025 huggingface dataset:
On chaos synchronization and secure communication
Authors: Kinzel W. , Englert A. , Kanter I.
Published: December 2009

Chaos synchronization, in particular isochronal synchronization of two chaotic trajectories to each other, may be used to build a means of secure communication over a public channel. In this paper, we give an overview of coupling schemes of Bernoulli units deduced from chaotic laser systems, different ways to transmit information by chaos synchronization and the advantage of bidirectional over unidirectional coupling with respect to secure communication. We present the protocol for using dynamical private commutative filters for tap-proof transmission of information that maps the task of a passive attacker to the class of non-deterministic polynomial time-complete problems.
Delay stabilization of periodic orbits in coupled oscillator systems
Authors: Fiedler B. , Flunkert V. , Hövel P. , Schöll E.
Published: December 2009

We study diffusively coupled oscillators in Hopf normal form. By introducing a non-invasive delay coupling, we are able to stabilize the inherently unstable anti-phase orbits. For the super- and subcritical cases, we state a condition on the oscillator’s nonlinearity that is necessary and sufficient to find coupling parameters for successful stabilization. We prove these conditions and review previous results on the stabilization of odd-number orbits by time-delayed feedback. Finally, we illustrate the results with numerical simulations.
On the origin of chaos in autonomous Boolean networks
Authors: Cavalcante Hugo L. D. de S. , Gauthier Daniel J. , Socolar Joshua E. S. , Zhang Rui
Published: December 2009

We undertake a systematic study of the dynamics of Boolean networks to determine the origin of chaos observed in recent experiments. Networks with nodes consisting of ideal logic gates are known to display either steady states, periodic behaviour or an ultraviolet catastrophe where the number of logic-transition events circulating in the network per unit time grows as a power law. In an experiment, the non-ideal behaviour of the logic gates prevents the ultraviolet catastrophe and may lead to deterministic chaos. We identify certain non-ideal features of real logic gates that enable chaos in experimental networks. We find that short-pulse rejection and asymmetry between the logic states tend to engender periodic behaviour, at least for the simplest networks. On the other hand, we find that a memory effect termed ‘degradation’ can generate chaos. Our results strongly suggest that deterministic chaos can be expected in a large class of experimental Boolean-like networks. Such devices may find application in a variety of technologies requiring fast complex waveforms or flat power spectra, and can be used as a test-bed for fundamental studies of real-world Boolean-like networks.
Genetic dissection of the miR-17∼92 cluster of microRNAs in Myc-induced B-cell lymphomas
Authors: Mu Ping , Han Yoon-Chi , Betel Doron , Yao Evelyn , Squatrito Massimo , Ogrodowski Paul , de Stanchina Elisa , D'Andrea Aleco , Sander Chris , Ventura Andrea
Published: December 2009

The miR-17∼92 cluster is frequently amplified or overexpressed in human cancers and has emerged as the prototypical oncogenic polycistron microRNA (miRNA). miR-17∼92 is a direct transcriptional target of c-Myc, and experiments in a mouse model of B-cell lymphomas have shown cooperation between these two oncogenes. However, both the molecular mechanism underlying this cooperation and the individual miRNAs that are responsible for it are unknown. By using a conditional knockout allele of miR-17∼92, we show here that sustained expression of endogenous miR-17∼92 is required to suppress apoptosis in Myc-driven B-cell lymphomas. Furthermore, we show that among the six miRNAs that are encoded by miR-17∼92, miR-19a and miR-19b are absolutely required and largely sufficient to recapitulate the oncogenic properties of the entire cluster. Finally, by combining computational target prediction, gene expression profiling, and an in vitro screening strategy, we identify a subset of miR-19 targets that mediate its prosurvival activity.
Increasing Sucrose Uptake Capacity of Wheat Grains Stimulates Storage Protein Synthesis
Authors: Weichert Nicola , Saalbach Isolde , Weichert Heiko , Kohl Stefan , Erban Alexander , Kopka Joachim , Hause Bettina , Varshney Alok , Sreenivasulu Nese , Strickert Marc , Kumlehn Jochen , Weschke Winfriede , Weber Hans
Published: December 2009

Increasing grain sink strength by improving assimilate uptake capacity could be a promising approach toward getting higher yield. The barley (Hordeum vulgare) sucrose transporter HvSUT1 (SUT) was expressed under control of the endosperm-specific Hordein B1 promoter (HO). Compared with the wild type, transgenic HOSUT grains take up more sucrose (Suc) in vitro, showing that the transgene is functional. Grain Suc levels are not altered, indicating that Suc fluxes are influenced rather than steady-state levels. HOSUT grains have increased percentages of total nitrogen and prolamins, which is reflected in increased levels of phenylalanine, tyrosine, tryptophan, isoleucine, and leucine at late grain development. Transcript profiling indicates specific stimulation of prolamin gene expression at the onset of storage phase. Changes in gene expression and metabolite levels related to carbon metabolism and amino acid biosynthesis suggest deregulated carbon-nitrogen balance, which together indicate carbon sufficiency and relative depletion of nitrogen. Genes, deregulated together with prolamin genes, might represent candidates, which respond positively to assimilate supply and are related to sugar-starch metabolism, cytokinin and brassinosteroid functions, cell proliferation, and sugar/abscisic acid signaling. Genes showing inverse expression patterns represent potential negative regulators. It is concluded that HvSUT1 overexpression increases grain protein content but also deregulates the metabolic status of wheat (Triticum aestivum) grains, accompanied by up-regulated gene expression of positive and negative regulators related to sugar signaling and assimilate supply. In HOSUT grains, alternating stimulation of positive and negative regulators causes oscillatory patterns of gene expression and highlights the capacity and great flexibility to adjust wheat grain storage metabolism in response to metabolic alterations.
Vested Interests in Addiction Research and Policy Alcohol policies out of context: drinks industry supplanting government role in alcohol policies in sub‐Saharan Africa
Authors: Bakke Øystein , Endal Dag
Published: December 2009

Background In this paper, we describe an analysis of alcohol policy initiatives sponsored by alcohol producer SABMiller and the International Center on Alcohol Policies, an alcohol industry‐funded organization. In a number of sub‐Saharan countries these bodies have promoted a ‘partnership’ role with governments to design national alcohol policies.

Methodology A comparison was conducted of four draft National Alcohol Policy documents from Lesotho, Malawi, Uganda and Botswana using case study methods.

Findings The comparison indicated that the four drafts are almost identical in wording and structure and that they are likely to originate from the same source.

Conclusions The processes and the draft policy documents reviewed provide insights into the methods, as well as the strategic and political objectives of the multi‐national drinks industry. This initiative reflects the industry's preferred version of a national alcohol policy. The industry policy vision ignores, or chooses selectively from, the international evidence base on alcohol prevention developed by independent alcohol researchers and disregards or minimizes a public health approach to alcohol problems. The policies reviewed maintain a narrow focus on the economic benefits from the trade in alcohol. In terms of alcohol problems (and their remediation) the documents focus upon individual drinkers, ignoring effective environmental interventions. The proposed policies serve the industry's interests at the expense of public health by attempting to enshrine ‘active participation of all levels of the beverage alcohol industry as a key partner in the policy formulation and implementation process’.
Dispersal of large farmed Atlantic salmon, Salmo salar, from simulated escapes at fish farms in Norway and Scotland
Authors: HANSEN L. P. , YOUNGSON A. F.
Published: December 2009

Abstract  Individually tagged farmed Atlantic salmon, Salmo salar L., were released from fish farms in simulated escapes in Scotland (n = 678) and Norway (n = 597) to compare migratory behaviour and dispersal. Large fish (510–870 mm fork length) were released to simulate the escape of aquaculture growers. Fish were released in spring and all recaptures of tagged fish were reported during summer and autumn of the year of release. Recapture rates were respectively 7.0 and 0.6% of the salmon released in Norway and Scotland, indicating a higher mortality or a lower exploitation or reporting rate for Scottish fish. Recaptures of Norwegian fish were all from Norway and mostly within 150 km of the release site; 64% were taken by anglers in fresh water. By contrast, the three salmon recaptured from the release in Scotland were reported from Norway (Hardangerfjord and Lofoten) and western Sweden (River Göta); two detached tags were found on beaches in Scotland north of the release site. These findings establish the capacity for long distance dispersal among escapees from aquaculture facilities and suggest a net easterly bias in long distance dispersal of salmon escaping from Scottish fish farms.
Responses of fluvial fish assemblages to agriculture within the boreal zone
Authors: SUTELA T. , VEHANEN T.
Published: December 2009

Abstract  The effect of agriculture on fish assemblages was assessed using electric fishing data from 108 sites on 27 medium‐sized rivers running through organic soils in central and northern Finland. The intensity of agriculture was quantified as the percentage of the catchment area used for agriculture (range 0–31%). High correlations (r2 = 0.68–0.86) were found between the intensity of agriculture and water quality parameters, especially total phosphorus, suspended solids and chemical oxygen demand. Densities of bullhead, Cottus gobio L., alpine bullhead, Cottus poecilopus Heckel, minnow, Phoxinus phoxinus (L.) and brown trout, Salmo trutta L., declined with increasing intensity of agriculture. Conversely, density of perch, Perca fluviatilis L., and roach, Rutilus rutilus (L.), increased with intensity of agriculture. A fish‐based index developed for the evaluation of the ecological integrity of rivers correlated negatively with the intensity of agriculture.
An open clinical study assessing the efficacy and safety of Factor IX Grifols®, a high‐purity Factor IX concentrate, in patients with severe haemophilia B
Authors: LISSITCHKOV T. , MATYSIAK M. , ZAWILSKA K. , GERCHEVA L. , ANTONOV A. , MONTAÑES M. , PAEZ A.
Published: December 2009

Summary.  Factor IX Grifols® is a new high‐purity plasma‐derived FIX concentrate with two specific pathogen elimination steps. Until this study was performed, there were no detailed reports with an adequate number of patients on the clinical evaluation of this product. To determine the efficacy and safety of Factor IX Grifols® for replacement therapy in previously treated patients with severe haemophilia B, this open, multicentre and non‐randomized study included 25 male subjects over the age of 12 with severe haemophilia B. Patients underwent prophylaxis and treatment of bleeding episodes with Factor IX Grifols® for 1 year. The clinical efficacy and safety of this product were assessed. Forty percent of the patients were children and adolescents (12–17 years old). During the 12 months follow‐up, 1 446 000 IU of Factor IX Grifols® were administered in 961 infusions (range 12–83 infusions per patient): 31% for prophylaxis and 69% for bleeding episodes. Only five major bleeding events were reported in two patients. These haemorrhages were successfully treated with a mean of 2900 IU per bleed (range 1500–4000 IU), and 1–3 infusions per bleed. The average time elapsed from the first infusion to resolution of bleeding was 43 h (median). Overall, haemostasis was rated as excellent or good by the investigator in 96% of the infusions. No product‐related adverse events were reported. Factor IX Grifols® is an effective and safe Factor IX concentrate and can be considered as a first line option for replacement therapy in haemophilia B patients.
Survival of Pseudoperonospora cubensis sporangia exposed to solar radiation
Authors: Kanetis L. , Holmes G. J. , Ojiambo P. S.
Published: December 2009

To determine the effects of solar radiation on the survival of sporangia of Pseudoperonospora cubensis, the cause of cucurbit downy mildew, detached sporangia of P. cubensis were either exposed to the sun or placed in the shade from 08·00 to 17·00 h on sunny and cloudy days at Raleigh, North Carolina, in experiments conducted weekly from 9 July to 8 October 2008. Sporangia were assessed for germination every hour following exposure and germination was normalized based on the germination percentage of unexposed sporangia from the same collection. Exposure for a 9‐h period, either in the sun or in the shade, significantly (P < 0·0001) reduced normalized germination of sporangia. Decrease in normalized germination was significantly (P < 0·0001) higher for sporangia exposed to the sun than sporangia in the shade, with the decrease being more rapid on sunny days than on cloudy days. On sunny days, solar radiation strongly reduced germination of sporangia (β = −3·51), whilst on cloudy days, reduction in germination of sporangia was minimal (β = −0·77). On sunny days, an exponential decay model, y = 95·2exp(−0·10x), provided a significant (R2 = 75·4%, n = 81, P < 0·0001) quantitative description of the effect of solar radiation dose on the percentage of normalized germination of sporangia. The effective cumulative solar radiation dose to inactivate 95% of the sporangia on sunny days was 29·5 MJ m−2. Disease severity data from inoculation experiments using sporangia exposed to varying amounts of cumulative solar radiation doses corroborated the results of the solar radiation experiments.
Genetic variation in flowering phenology and avoidance of seed predation in native populations of Ulex europaeus
Authors: ATLAN A. , BARAT M. , LEGIONNET A. S. , PARIZE L. , TARAYRE M.
Published: December 2009

The genetic variation in flowering phenology may be an important component of a species’ capacity to colonize new environments. In native populations of the invasive species Ulex europaeus, flowering phenology has been shown to be bimodal and related to seed predation. The aim of the present study was to determine if this bimodality has a genetic basis, and to investigate whether the polymorphism in flowering phenology is genetically linked to seed predation, pod production and growth patterns. We set up an experiment raising maternal families in a common garden. Based on mixed analyses of variance and correlations among maternal family means, we found genetic differences between the two main flowering types and confirmed that they reduced seed predation in two different ways: escape in time or predator satiation. We suggest that this polymorphism in strategy may facilitate maintain high genetic diversity for flowering phenology and related life‐history traits in native populations of this species, hence providing high evolutionary potential for these traits in invaded areas.
Are you my mother? Kin recognition in the ant Formica fusca
Authors: EL‐SHOWK S. , Van ZWEDEN J. S. , D’ETTORRE P. , SUNDSTRÖM L.
Published: December 2009

In social insects, workers trade personal reproduction for indirect fitness returns from helping their mother rear collateral kin. Colony membership is generally used as a proxy for kin discrimination, but the question remains whether recognition allows workers to discriminate between kin and nonkin regardless of colony affiliation. We investigated whether workers of the ant Formica fusca can identify their mother when fostered with their mother, their sisters, a hetero‐colonial queen or hetero‐colonial workers. We found that workers always displayed less aggression towards both their mother and their foster queen, as compared to an unfamiliar hetero‐colonial queen. In support of this finding, workers maintain their colony hydrocarbon profile regardless of foster regime, yet show modifications when exposed to different environments. This indicates that recognition entails environmental and genetic components, which allow both discrimination of kin in the absence of prior contact and learning of recognition cues based on group membership.
Innate Predator Recognition and the Problem of Introduced Trout
Authors: Gall Brian G. , Mathis Alicia
Published: December 2009

Innate predator recognition typically only occurs when there is an evolutionary history between predator and prey. Predator introductions thus can pose a substantial threat to native fauna that rely heavily on inherent identification of predators. In permanent aquatic habitats prey often encounter a variety of predatory and non‐predatory fish species, and the ability to distinguish between the two is essential to avoid wasted time and energy spent in unnecessary antipredatory efforts. Here, we present a study evaluating the ability of lab‐reared larvae of an endangered fully aquatic salamander (hellbenders: Cryptobranchus alleganiensis) to recognize chemical cues from native and introduced fish predators. We recorded responses of hellbender larvae to chemical stimuli from native and non‐native predatory fishes, a non‐predatory fish and a blank control. Eastern hellbender larvae (C. a. alleganiensis) significantly reduced activity in response to chemical stimuli from native predators (Micropterus salmoides, Micropterus dolomieu, Ambloplites rupestris, Sander vitreus, and Cottus carolinae), but responses to non‐native rainbow (Oncorhynchus mykiss) and brown (Salmo trutta) trout were not significantly different from responses to the non‐predatory control (redhorse sucker, Moxostoma spp.). Responses of larval Ozark hellbenders (C. a. bishopi) to brown trout were similar to that of the native fishes and different from the blank control, but responses to rainbow trout did not differ from the blank control. The generally weak responses of larval hellbenders to chemical cues from introduced predatory trout could lead to increased predation in the wild, which may have exacerbated the decline of hellbender populations.
Flight and crawling activities of Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) in relation to morphometric traits
Authors: Li H. , Toepfer S. , Kuhlmann U.
Published: December 2009

Morphometric traits and body weight are often used to study changes in fitness. For the invasive alien maize pest, Diabrotica virgifera virgifera LeConte, little information is available regarding the possible relationship between morphometric traits and adult activity, which reflects the ability to disperse and invade. Flight and crawling activities of D. v. virgifera adults were investigated in relation to six different morphometric traits as well as body weight, sex and age. This laboratory study revealed that flight activity of D. v. virgifera differed between sexes and changed with age. Young adults of both sexes flew more frequently and took off faster than mature adults. Males flew more frequently and took off faster than females, regardless of age‐class. No such differences were found for crawling frequency, but young males crawled faster than young females. Further analysis revealed that fresh body weight and morphometric traits of young adults were better predictors of flight and crawling activity than the same measurements made on mature adults. Particularly pronotum and elytra measurements on young adults are recommended for bioassay studies on activity parameters of D. v. virgifera.
Molecular Characterization and Epidemiology of Ralstonia solanacearum Race 3 biovar 2 Causing Brown Rot of Potato in Mauritius
Authors: Khoodoo Michel Hans Rodney , Ganoo Edhabye Shandra , Saumtally Abdess Salem
Published: December 2009

Outbreaks of brown rot disease caused by Ralstonia solanacearum Race 3 biovar 2 have resulted in losses of 291 t of potato, worth approximately USD 171 000 since 2005 over three growing seasons. The gradual spread of this quarantine disease in Mauritius has warranted a study of the population of the pathogen. The epidemiological and ecological groupings of R. solanacearum isolated from outbreaks in Mauritius from 2005 to 2008 were examined following a study of their genetic relatedness by PCR‐based marker amplified with REP and IS1112 PCR primers. The band‐based genomic fingerprint data clustered strains in two major groups B and C, and one minor group A. Group B comprised exclusively of strains that caused the outbreaks in 2008 and appeared to originate from a different clonal lineage from strains clustered in groups A and C. Nucleotide polymorphisms within each group and shared markers suggest that group B strains could represent a novel introduction of the pathogen compared to the initial population of strains responsible for the outbreaks in 2005 and 2006. The clustering of strains isolated from imported ware potatoes obtained from the local market support the hypothesis that this could be a source of entry of the pathogen in Mauritius.
FEASIBILITY OF ENDOSCOPIC SUBMUCOSAL DISSECTION FOR PATIENTS WITH CHRONIC RENAL FAILURE ON HEMODIALYSIS
Authors: Goto Osamu , Fujishiro Mitsuhiro , Kodashima Shinya , Ono Satoshi , Niimi Keiko , Yamamichi Nobutake , Omata Masao
Published: December 2009

Background:  Endoscopic submucosal dissection (ESD) is expected as a curative method for node‐negative gastrointestinal cancers. Little is known about ESD for patients with end‐stage chronic renal failure (CRF) on hemodialysis. We aimed to evaluate the efficacy and safety of ESD for patients with CRF on hemodialysis.

Methods:  Ten consecutive patients with 12 lesions who underwent ESD (stomach, seven; colorectum, three) between March 2002 and August 2007 were retrospectively investigated in terms of the technical feasibility and complications.

Results:  All the lesions were resected in a single piece and en‐bloc and R0 resection rate was 100%. Histology revealed that all the lesions fulfilled the criteria of node‐negative cancers. Delayed bleeding requiring blood transfusion on the day after ESD, and shunt occlusion, which necessitated a radiological intervention 7 days after ESD, occurred in one stomach case. Delayed perforation followed by emergency surgery 2 days after ESD occurred in one colorectal case.

Conclusions:  ESD for CRF patients may be technically feasible, but substantial risks should be considered. Early detection of late‐onset complications is essential with intensive medical check‐up for at least 1 week in order to prevent complications from becoming severe.
Outcome and long‐term function of restorative proctocolectomy for Crohn’s disease: comparison to patients with ulcerative colitis
Authors: Grucela A. L. , Bauer J. J. , Gorfine S. R. , Chessin D. B.
Published: December 2009

Aim  Restorative proctocolectomy (RPC) is the most common operation for chronic ulcerative colitis (CUC), as it provides excellent functional outcome. However, among patients with Crohn’s disease (CD), RPC is generally not recommended, as outcome and long‐term function may be poor. Our purpose was to compare matched cohorts of CD and CUC patients to determine whether there are differences in outcome or function.

Method  We queried our prospectively maintained database of patients who underwent RPC from 1991 to 2008. We identified patients who underwent RPC for CD and compared them with a matched cohort of patients who underwent RPC for CUC.

Results  We identified 13 patients with CD (seven women, median age 34 years) and 39 patients with CUC (21 women, median age 35 years). The patients were well matched for gender, clinical and demographic variables. Seven patients (54%) with CD had proctitis, but none had perianal or ileal disease. There were four (30.8%) postoperative complications and no anastomotic leaks. The CD group experienced significantly fewer median daily bowel movements (P = 0.02), incontinence for liquids (P < 0.01) and pouchitis (P < 0.01). With a median follow up of 44 months, pouch excision rate was significantly higher in the Crohn’s group (2 vs 0%, P < 0.01).

Conclusion  In patients with CD, RPC may result in fewer daily bowel movements, less liquid incontinence and a lower incidence of pouchitis compared with CUC patients who undergo RPC. However, risk of pouch loss is higher in patients with CD. Therefore, in properly selected patients with CD, RPC provides an acceptable long‐term functional outcome.
Serious unconventional complications of surgery with stapler for haemorrhoidal prolapse and obstructed defaecation because of rectocoele and rectal intussusception
Authors: Naldini G.
Published: December 2009

Aim  Treatment of haemorrhoidal prolapse by stapled haemorrhoidopexy (SH) and obstructed defaecation syndrome with the stapled transanal rectal resection (STARR) technique is becoming increasingly popular with patients and surgeons. Unfortunately, serious complications have been identified. The aim of the present study was to analyse the complications and their treatment to see where they might be avoided and to determine best management.

Method  All Units of Coloproctology belonging to the Italian Unitary Society of Coloproctology (SIUCP) were asked to return documentation of serious complications following SH and STARR.

Results  Forty‐six reports were received from 23 centres. Twenty‐seven serious complications were reported. Twenty occurred after SH (13 PPH 03, 7 PPH 01) (Endo‐surgery Inc., Cincinnati, Ohio, USA) and seven after STARR. Complications were treated by abdominal operation in nine patients [colostomy (3), ileostomy (2), Hartmann’s resection (1) and anterior resection (1)].

Conclusion  Stapled haemorrhoidopexy and STARR can result in serious complications requiring major surgery for their treatment.
Bladder malignancies in children aged <18 years: results from the Surveillance, Epidemiology and End Results database
Authors: Alanee Shaheen , Shukla Aseem R.
Published: December 2009

Study Type – Prognosis (inception cohort) Level of Evidence 1b

OBJECTIVE

To present descriptive statistics for bladder tumours in children, calculated from the Surveillance, Epidemiology and End Results (SEER) database, as bladder malignancies are relatively uncommon in children, causing difficulty in understanding their incidence and survival.

PATIENTS AND METHODS

The SEER database was interrogated to report the incidence of bladder malignancies in children from birth to 18 years old. Race and sex differences were assessed. The 5‐year survival by disease stage at diagnosis and 5‐year conditional survival after surviving for 1–3 years is reported for 1973–2003. The incidence and survival rates for bladder embryonal rhabdomyosarcoma were further characterized.

RESULTS

We identified 140 cases of bladder cancers in the selected cohort. Papillary urothelial neoplasm of low malignant potential (PUNLMP) and rhabdomyosarcoma comprised 50.7% and 36.4% of the tumours, respectively. The incidence of bladder malignancies significantly increased between 1973 and 2003. Conditional survival calculated for 1 and 2 years after disease diagnosis was 93.6% and 97.5%. Fifty‐one cases of embryonal rhabdomyosarcoma were identified. The male to female incidence ratio was ≈2:1 for these tumours. The 5‐year survival rates were 50–80% over the past three decades.

CONCLUSIONS

We present the most contemporary survey of the SEER database for the incidence and survival for bladder tumours in children. Depending on the patient’s age, PUNLMP and rhabdomyosarcoma predominated in different proportions. The 2–3‐year conditional survival and overall survival were excellent. We also identified improving survival for embryonal bladder rhabdomyosarcoma with time.
Bat metacommunity structure on Caribbean islands and the role of endemics
Authors: Presley Steven J. , Willig Michael R.
Published: December 2009

Aim  We evaluate characteristics of species ranges (i.e. coherence, species turnover and range boundary clumping) to determine the structure of bat metacommunities and metaensembles from Caribbean islands. We evaluate the effects of endemic species on that structure, and quantify associations between island characteristics and latent environmental gradients that structure these metacommunities and metaensembles.

Location  Sixty‐five Caribbean islands throughout the Bahamas, Greater Antilles and Lesser Antilles.

Methods  Metacommunity structure is an emergent property of a set of ecological communities at different sites defined by species distributions across geographic or environmental gradients. We analysed elements of metacommunity structure (coherence, range turnover and range boundary clumping) to determine the best‐fit pattern for metacommunities from all Caribbean islands, as well as from the Bahamas, the Greater Antilles and the Lesser Antilles separately. For each island group, analyses were conducted for all bats and for each of two broadly defined guilds (i.e. carnivores and herbivores). In addition, analyses were conducted for all species and for a subset in which endemic species were removed from the fauna. Spearman rank correlations identified island characteristics (area, elevation, latitude, longitude) that were associated significantly with island scores for ordination axes based on reciprocal averaging.

Results  Metacommunity structure for all bats and for carnivores was similar for each island group, with Clementsian distributions (i.e. discrete communities with groups of species replacing other groups of species along the gradient) for all islands, the Bahamas and the Lesser Antilles, but with nested distributions for the Greater Antilles. Herbivore distributions were random for the Bahamas, but were Clementsian for all other island groups. Removal of endemic species affected the best‐fit model of metacommunity structure in only 3 of 12 cases. In general, ordination scores for islands were correlated with longitude or latitude, but not with island area or elevation.

Main conclusions  Characteristics of bat species ranges and associated metacommunity structure were primarily dependent on the number and geographic arrangement of primary sources of colonization, and not on interspecific interactions, species‐specific levels of environmental tolerance, or the physical characteristics of islands. Endemic species did not greatly affect metacommunity structure in Caribbean bats.
Estimating and controlling for spatial structure in the study of ecological communities
Authors: Peres‐Neto Pedro R. , Legendre Pierre
Published: December 2009

Aim  Variation partitioning based on canonical analysis is the most commonly used analysis to investigate community patterns according to environmental and spatial predictors. Ecologists use this method in order to understand the pure contribution of the environment independent of space, and vice versa, as well as to control for inflated type I error in assessing the environmental component under spatial autocorrelation. Our goal is to use numerical simulations to compare how different spatial predictors and model selection procedures perform in assessing the importance of the spatial component and in controlling for type I error while testing environmental predictors.

Innovation  We determine for the first time how the ability of commonly used (polynomial regressors) and novel methods based on eigenvector maps compare in the realm of spatial variation partitioning. We introduce a novel forward selection procedure to select spatial regressors for community analysis. Finally, we point out a number of issues that have not been previously considered about the joint explained variation between environment and space, which should be taken into account when reporting and testing the unique contributions of environment and space in patterning ecological communities.

Main conclusions  In tests of species‐environment relationships, spatial autocorrelation is known to inflate the level of type I error and make the tests of significance invalid. First, one must determine if the spatial component is significant using all spatial predictors (Moran's eigenvector maps). If it is, consider a model selection for the set of spatial predictors (an individual‐species forward selection procedure is to be preferred) and use the environmental and selected spatial predictors in a partial regression or partial canonical analysis scheme. This is an effective way of controlling for type I error in such tests. Polynomial regressors do not provide tests with a correct level of type I error.
Percentile distributions of waist circumference for 7–19‐year‐old Polish children and adolescents
Authors: Nawarycz L. Ostrowska , Krzyżaniak A. , Stawińska‐Witoszyńska B. , Krzywińska‐Wiewiorowska M. , Szilagyi‐Pągowska I. , Kowalska M. , Krzych Ł. , Nawarycz T.
Published: December 2009

The aim of the study was to develop waist circumference (WC) percentiles in Polish children and youth and to compare these with the results obtained in other countries. The study comprised a random group of 5663 Polish children aged 7–18 years. Smoothed WC percentile curves were computed using the LMS method. The curves displaying the values of the 50th (WC50) and the 90th (WC90) percentile were then compared with the results of similar studies carried out in children from the UK, Spain, Germany, Turkey, Cyprus, Canada and the USA. WC increased with age in both boys and girls and in all observed age periods the boys were seen to dominate. For 18‐year‐old Polish boys and girls the values of WC90 were 86.5 and 78.2, respectively, and were lower than the current criteria developed by the International Diabetes Federation. Both WC50 and WC90 were higher in Polish boys and girls compared with their counterparts in the UK, Turkey and Canada and significantly lower than in children from the USA, Cyprus and Spain. The percentile curves for Polish children and youth, which were developed here for the first time, are base curves that can be applied in analysing trends as well as making comparisons with results of similar studies performed in other countries.
Treatment of clinical insulin resistance in children: a systematic review
Authors: Quinn S. M. , Baur L. A. , Garnett S. P. , Cowell C. T.
Published: December 2009

The objective of this study was to evaluate the effectiveness of interventions aimed at improving clinical insulin resistance and/or pre‐diabetes in children. This study is a systematic review and meta‐analysis. Five electronic databases were searched for randomized controlled trials of at least 2‐months' duration. The outcomes were fasting insulin, homeostasis model assessment of insulin resistance (HOMA‐IR), body mass index (BMI) and adverse outcomes. Four randomized controlled trials were identified. All compared the effect of 6 months of metformin plus or minus lifestyle intervention with placebo plus or minus lifestyle intervention. After pooling results from three trials, the mean difference after 6 months favoured the intervention with a statistically significant mean decrease in fasting insulin, HOMA‐IR and BMI of 9.6 µU mL−1 (95% confidence interval [CI]: 6.3, 13.0 µU mL−1; I2 = 76%), 2.7 (95% CI: 1.7, 3.6; I2 = 74%) and 1.7 kg m−2 (95% CI: 1.1, 2.3 kg m−2; I2 = 75) respectively. Mild gastrointestinal symptoms were reported in 19% (2–29%; median and range) of participants taking metformin. Metformin improves markers of insulin sensitivity and reduces BMI in children and adolescents with clinical insulin resistance or pre‐diabetes. Stronger evidence from high‐quality studies of longer duration and larger sample size are required before clinical conclusions about the optimal treatment protocol in this population can be drawn.
Multihulls: A Technique for Spatial Representation and Processing with Variable Shape Fidelity, Applied to Gazetteers
Authors: Hastings Jordan T.
Published: December 2009

Spatial processing is increasingly prevalent in the modern computing milieu. In particular, geographic information retrieval and location‐based services such as GoogleEarth and MapQuest depend on spatial operations in conjunction with gazetteers to georeference geographic features. However, many gazetteers contain only point locations or simple bounding rectangles, which make for erratic and sometimes poor georeferencing. Convex hulls can provide better georeferencing results at modest computational cost, but their shape fidelity is still erratic. Full GIS capabilities are actually overfit for many geospatial and georeferencing purposes, because of the limited accuracy of the underlying data. The financial and technical demands of GIS also exclude it from many markets. Described here is a new technique, multihulls, based on the iterative refinement of convex hulls. Multihulls achieve arbitrary shape fidelity at a small increment in computational cost, consistent with the data, outside a GIS, making them attractive for many geospatial and georeferencing applications, especially gazetteers.
Consumer‐Oriented Health Care Reform Strategies: A Review of the Evidence on Managed Competition and Consumer‐Directed Health Insurance
Authors: BUCHMUELLER THOMAS C.
Published: December 2009

Context: For many years, leading health care reform proposals have been based on market‐oriented strategies. In the 1990s, a number of reform proposals were built around the concept of “managed competition,” but more recently, “consumer‐directed health care” models have received attention. Although price‐conscious consumer demand plays a critical role in both the managed competition and consumer‐directed health care models, the two strategies are based on different visions of the health care marketplace and the best way to use market forces to achieve greater systemwide efficiencies.

Methods: This article reviews the research literature that tests the main hypotheses concerning the two policy strategies.

Findings: Numerous studies provide consistent evidence that consumers’ health plan choices are sensitive to out‐of‐pocket premiums. The elasticity of demand appears to vary with consumers’ health risk, with younger, healthier individuals being more price sensitive. This heterogeneity increases the potential for adverse selection. Biased risk selection also is a concern when the menu of health plan options includes consumer‐directed health plans. Several studies confirm that such plans tend to attract healthier enrollees. A smaller number of studies test the main hypothesis regarding consumer‐directed health plans, which is that they result in lower medical spending than do more generous plans. These studies find little support for this claim.

Conclusions: The experiences of employers that have adopted key elements of managed competition are generally consistent with the key hypotheses underlying that strategy. Research in this area, however, has focused on only a narrow range of questions. Because consumer‐directed health care is such a recent phenomenon, research on this strategy is even more limited. Additional studies on both topics would be valuable.
Aging in America in the Twenty‐first Century: Demographic Forecasts from the MacArthur Foundation Research Network on an Aging Society
Authors: OLSHANSKY S. JAY , GOLDMAN DANA P. , ZHENG YUHUI , ROWE JOHN W.
Published: December 2009

Context: The aging of the baby boom generation, the extension of life, and progressive increases in disability‐free life expectancy have generated a dramatic demographic transition in the United States. Official government forecasts may, however, have inadvertently underestimated life expectancy, which would have major policy implications, since small differences in forecasts of life expectancy produce very large differences in the number of people surviving to an older age. This article presents a new set of population and life expectancy forecasts for the United States, focusing on transitions that will take place by midcentury.

Methods: Forecasts were made with a cohort‐components methodology, based on the premise that the risk of death will be influenced in the coming decades by accelerated advances in biomedical technology that either delay the onset and age progression of major fatal diseases or that slow the aging process itself.

Findings: Results indicate that the current forecasts of the U.S. Social Security Administration and U.S. Census Bureau may underestimate the rise in life expectancy at birth for men and women combined, by 2050, from 3.1 to 7.9 years.

Conclusions: The cumulative outlays for Medicare and Social Security could be higher by $3.2 to $8.3 trillion relative to current government forecasts. This article discusses the implications of these results regarding the benefits and costs of an aging society and the prospect that health disparities could attenuate some of these changes.
The Effect of Networks on the Selection of Migrants and Destinations: Colombians in Galicia (Spain)
Authors: Lamela Carmen , Pérez‐Caramés Antía , Fernández‐Suárez Belén
Published: December 2009

This article presents findings from a research project on Colombian transnational migration to a secondary and peripheral region of Spain. The transnational character of our object of study means that our methodology is mainly of an anthropological nature. But our analysis is also guided by demographic data and theories, so it can be considered a sample of work in the new field of anthropological demography. The article’s main purpose is to explore migration network effects on inflows, given the weakness of other pull factors. We believe that local or regional levels of analysis might reveal other aspects about migration determinants that get lost at the national level. Moreover, the links between migrant networks and the size of immigration flows should be more evident at the regional level of analysis. Both statistical data analysis and ethnographic evidence point to the same conclusion: network dynamics do not sufficiently explain inflows behaviour, nor migration strategies and Colombians migrants’ interaction in destination. Instead, we can infer the importance of powerful push factors, and of migration history and social change in the country of origin. A transnational mother profile plays a relevant role in the analysis of this case and of cumulative causation theory. Gathered testimonies and observed evolution of Colombian migration to Spain and Galicia suggest the activation of feminised networks and the inhibition of family reunification.
ORIGINAL ARTICLE: Pain in people with learning disabilities in residential settings – the need for change
Authors: Beacroft Monica , Dodd Karen
Published: December 2009

Accessible summary

 Pain is not recognised and managed well for people with learning disabilities in residential settings – People with learning disabilities are not getting timely and appropriate ‘as required’ medication for their pain.

 Staff do not use pain recognition tools or communication aids.

 Some staff still believe that people with learning disabilities have a higher pain threshold than people without a learning disability. They also let this belief affect how they manage pain.

 This research matters to people with learning disabilities. It is important that staff and carers recognise and manage pain well. We have developed a pain training pack for staff and carers and leaflets for both people with learning disabilities and staff and carers.

This audit investigated residential staff beliefs around pain thresholds and strategies they adopt to recognise and manage pain in people with learning disabilities across Surrey. A structured interview was constructed to elicit information. Results demonstrated that pain is not being effectively recognised or managed by residential staff in Surrey. It highlighted the need for training for staff in how to recognise and manage pain, as well as the need for appropriate pain recognition tools and communication aids to be utilised to support people with learning disabilities to be able to communicate their pain to others. It also indicated the need for better communication between staff and other services that the person with learning disabilities accesses.
Screening for mental health problems in adults with learning disabilities using the Mini PAS‐ADD Interview
Authors: Devine Maurice , Taggart Laurence , McLornian Paula
Published: December 2009

Accessible summary

This study interviewed the key workers of 96 adults with learning disabilities using the Mini PAS‐ADD Interview to identify whether they had a potential mental health problem. Prevalence rates of mental health across the UK and in other countries have been published but such figures are not known in Northern Ireland. This study found:

 33.3% of the sample was identified to have a potential mental health problem.

 This sample was found to score higher on the sub‐scales of depression and psychosis compared with other prevalence studies.

 The community informants (i.e. nurses and social workers) were found to be competent in using the Mini PAS‐ADD Interview as identified by the sample of in‐depth psychiatric interviews undertaken by a psychiatrist.

Prevalence rates vary considerably regarding the mental health of people with learning disabilities. This variation is a consequence of the assessment methods used to identify such clinical conditions and also different populations studied. The aim of this study was to screen for mental health problems in adults with mild‐to‐moderate learning disabilities. This study took place in one region of the UK providing community‐based services to 96 adults with mild‐to‐moderate learning disabilities. Using the Mini PAS‐ADD Interview schedule, a number of specifically trained interviewers, interviewed staff who supported these adults with learning disabilities in their particular work/day care setting to determine whether or not participants had a potential mental health problem. This study found a 33.3% prevalence rate of mental health problems in this community sample. This sample was found to score higher on the sub‐scales of depression and psychosis compared with other prevalence studies. The Mini PAS‐ADD Interview was found have an overall sensitivity of 1 (100%); its specificity was 77%. The results of this study fall between previous community prevalence studies that range from 14% to 50%. The practical issues of the screening process are discussed. Methodological limitations are also highlighted in accurately predicting prevalence rates of mental health problems in the learning disability population by clinical staff.