Arctic systems in the Quaternary: ecological collision, faunal mosaics and the consequences of a wobbling climate.

Climate oscillations and episodic processes interact with evolution, ecology and biogeography to determine the structure and complex mosaic that is the biosphere. Parasites and parasite-host assemblages are key components in a general explanatory paradigm for global biodiversity. We explore faunal assembly in the context of Quaternary time frames of the past 2.6 million years, a period dominated by episodic shifts in climate. Climate drivers cross a continuum from geological to contemporary timescales and serve to determine the structure and distribution of complex biotas. Cycles within cycles are apparent, with drivers that are layered, multifactorial and complex. These cycles influence the dynamics and duration of shifts in environmental structure on varying temporal and spatial scales. An understanding of the dynamics of high-latitude systems, the history of the Beringian nexus (the intermittent land connection linking Eurasia and North America) and downstream patterns of diversity depend on teasing apart the complexity of biotic assembly and persistence. Although climate oscillations have dominated the Quaternary, contemporary dynamics are driven by tipping points and shifting balances emerging from anthropogenic forces that are disrupting ecological structure. Climate change driven by anthropogenic forcing has supplanted a history of episodic variation and is eliminating ecological barriers and constraints on development and distribution for pathogen transmission. A framework to explore interactions of episodic processes on faunal structure and assembly is the Stockholm Paradigm, which appropriately shifts the focus from cospeciation to complexity and contingency in explanations of diversity.

Precision large field scanning system for high numerical aperture lenses and application to femtosecond micromachining of ophthalmic materials.

A precision, large stroke (nearly 1 cm) scanning system was designed, built, and calibrated for micromachining of ophthalmic materials including hydrogels and cornea (excised and in vivo). This system comprises a flexure stage with an attached objective on stacked vertical and horizontal translation stages. This paper outlines the design process leading to our most current version including the specifications that were used in the design and the drawbacks of other methods that were previously used. Initial measurements of the current version are also given. The current flexure was measured to have a 27 Hz natural frequency with no load.

Epidemia de enfermedad renal crónica en Centroamérica / An epidemic of chronic kidney disease in Central America: an overview

En varios países de la región centroamericana la enfermedad renal crónica se ha convertido en la primera causa de muerte en hombres jóvenes trabajadores sin antecedentes de enfermedades cardiovasculares. La falta de acceso por parte de los pacientes a terapias de sustitución renal (diálisis y/o transplante) hace que en algunas comunidades con elevada carga de enfermedad, ésta esté teniendo un alto impacto social y económico. Este editorial describe esta epidemia, recoge por primera la limitada evidencia científica hasta la fecha, explora las posibles hipótesis causales y prioriza intervenciones de salud pública necesarias a la luz de los resultados(AU)

Completion of isoniazid preventive therapy and survival in HIV-infected, TST-positive adults in Tanzania.

SETTING: The World Health Organization recommends the use of isoniazid preventive therapy (IPT) for human immunodeficiency virus (HIV) infected patients with a positive tuberculin skin test (TST). However, due to concerns about the effectiveness of IPT in community health care settings and the development of drug resistance, these recommendations have not been widely implemented in countries where tuberculosis (TB) and HIV co-infection is common. OBJECTIVE: To evaluate the effectiveness of IPT on survival and TB incidence among HIV-infected patients in Tanzania. DESIGN: A cohort study nested within a randomized trial of HIV-infected adults with baseline CD4 counts of ≥ 200 cells/µ l was conducted to compare survival and incidence of active TB between TST-positive subjects who did or did not complete 6 months of IPT in the period 2001-2008. RESULTS: Of 558 TST-positive subjects in the analytic cohort, 488 completed 6 months of IPT and 70 did not. Completers had a decrease in mortality compared to non-completers (HR 0.4, 95%CI 0.2-0.8). However, the protective effect of IPT on the incidence of active TB was non-significant (HR 0.6, 95%CI 0.3-1.3). CONCLUSION: Completion of IPT is associated with increased survival in HIV-infected adults with CD4 counts ≥ 200 cells/µ l and a positive TST.

Temporal trends in non-small cell lung cancer survival in Sweden.

We modeled temporal trends in the 1- and 5-year survival of 32 499 patients with adenocarcinoma and squamous cell carcinoma of the lung in the Swedish Cancer Register between 1961 and 2000. The 1-year relative survival for adenocarcinoma improved from 37% for patients diagnosed 1961-1965 to 45% for those diagnosed 1996-2000 and from 39 to 45% for squamous cell carcinoma. The adjusted excess mortality ratios for the period 1996-2000 compared with 1961-1965 were 0.80 for adenocarcinoma and 0.81 for squamous cell carcinoma. Thus, a previous report in a Dutch study of a relatively worsening prognosis for adenocarcinoma over time could not be confirmed.

Effects of genetically modified herbicide-tolerant cropping systems on weed seedbanks in two years of following crops.

The Farm Scale Evaluations (FSEs) showed that genetically modified herbicide-tolerant (GMHT) cropping systems could influence farmland biodiversity because of their effects on weed biomass and seed production. Recently published results for winter oilseed rape showed that a switch to GMHT crops significantly affected weed seedbanks for at least 2 years after the crops were sown, potentially causing longer-term effects on other taxa. Here, we seek evidence for similar medium-term effects on weed seedbanks following spring-sown GMHT crops, using newly available data from the FSEs. Weed seedbanks following GMHT maize were significantly higher than following conventional varieties for both the first and second years, while by contrast, seedbanks following GMHT spring oilseed rape were significantly lower over this period. Seedbanks following GMHT beet were smaller than following conventional crops in the first year after the crops had been sown, but this difference was much reduced by the second year for reasons that are not clear. These new data provide important empirical evidence for longer-term effects of GMHT cropping on farmland biodiversity.

Effect of physician recommendation and patient adherence on rates of colorectal cancer testing.

This study explored: (1) patient characteristics associated with physician recommendation for colorectal cancer (CRC) screening and patient adherence to recommendation, and (2) the combined effect of recommendation and adherence on CRC testing, broadly defined. Data were from the 1999 MA BRFSS and a call-back survey of 869 BRFSS participants, age 50 and older. Logistic regression was used to identify correlates of recommendation, adherence, and testing. Patient-physician factors were positively associated with recommendation, adherence and testing. Inadequate health insurance was negatively associated with recommendation (OR = 0.45, 95% CI = 0.27-0.78) and testing (OR = 0.64, 95% CI = 0.38-1.1). Men were not more likely to be recommended (OR = 1.1, 95% CI = 0.78-1.5), but were more likely to adhere (OR = 1.9, 95% CI = 1.2-2.0) and to be tested (OR = 1.4, 95% CI = 1.0-1.9). There were gender differences in recommendation when considering health and risk factor measures. Research is needed to understand differences in recommendation and adherence. Greater encouragement and follow-through may be needed for groups less likely to adhere.

Effect of vagility potential on dispersal and speciation in rainforest insects.

Explaining global patterns of species diversity is one of the most challenging objectives in biology. Most agree that complex interactions between historical and current processes are responsible for such patterns, although rigorous testing of possible mechanisms has proved difficult. Here we demonstrate that macropterous and flightless insects in the rainforests of north-eastern Australia have dispersed and speciated in similar manners. These results contradict the traditionally held assumption that differences in vagility potential would lead to significant differences in distributional patterns and speciation modes.

On the rationale and interpretation of the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

Farmland biodiversity and food webs were compared in conventional and genetically modified herbicide-tolerant (GMHT) crops of beet (Beta vulgaris L.), maize (Zea mays L.) and both spring and winter oilseed rape (Brassica napus L.). GMHT and conventional varieties were sown in a split-field experimental design, at 60-70 sites for each crop, spread over three starting years beginning in 2000. This paper provides a background to the study and the rationale for its design and interpretation. It shows how data on environment, field management and the biota are used to assess the current state of the ecosystem, to define the typical arable field and to devise criteria for selecting, sampling and auditing experimental sites in the Farm Scale Evaluations. The main functional and taxonomic groups in the habitat are ranked according to their likely sensitivity to GMHT cropping, and the most responsive target organisms are defined. The value of the seedbank as a baseline and as an indicator of historical trends is proposed. Evidence from experiments during the twentieth century is analysed to show that large changes in field management have affected sensitive groups in the biota by ca. 50% during a year or short run of years--a figure against which to assess any positive or negative effects of GMHT cropping. The analysis leads to a summary of factors that were, and were not, examined in the first 3 years of the study and points to where modelling can be used to extrapolate the effects to the landscape and the agricultural region.

Crop management and agronomic context of the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

The Farm Scale Evaluations of genetically modified herbicide-tolerant crops (GMHT) were conducted in the UK from 2000 to 2002 on beet (sugar and fodder), spring oilseed rape and forage maize. The management of the crops studied is described and compared with current conventional commercial practice. The distribution of field sites adequately represented the areas currently growing these crops, and the sample contained sites operated at a range of management intensities, including low intensity. Herbicide inputs were audited, and the active ingredients used and the rates and the timings of applications compared well with current practice for both GMHT and conventional crops. Inputs on sugar beet were lower than, and inputs on spring oilseed rape and forage maize were consistent with, national averages. Regression analysis of herbicide-application strategies and weed emergence showed that inputs applied by farmers increased with weed densities in beet and forage maize. GMHT crops generally received only one herbicide active ingredient per crop, later and fewer herbicide sprays and less active ingredient (for beet and maize) than the conventional treatments. The audit of inputs found no evidence of bias.

Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. I. Soil-surface-active invertebrates.

The effects of herbicide management of genetically modified herbicide-tolerant (GMHT) beet, maize and spring oilseed rape on the abundance and diversity of soil-surface-active invertebrates were assessed. Most effects did not differ between years, environmental zones or initial seedbanks or between sugar and fodder beet. This suggests that the results may be treated as generally applicable to agricultural situations throughout the UK for these crops. The direction of the effects was evenly balanced between increases and decreases in counts in the GMHT compared with the conventional treatment. Most effects involving a greater capture in the GMHT treatments occurred in maize, whereas most effects involving a smaller capture were in beet and spring oilseed rape. Differences between GMHT and conventional crop herbicide management had a significant effect on the capture of most surface-active invertebrate species and higher taxa tested in at least one crop, and these differences reflected the phenology and ecology of the invertebrates. Counts of carabids that feed on weed seeds were smaller in GMHT beet and spring oilseed rape but larger in GMHT maize. In contrast, collembolan detritivore counts were significantly larger under GMHT crop management.

Invertebrates and vegetation of field margins adjacent to crops subject to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

The effects of management of genetically modified herbicide-tolerant (GMHT) crops on adjacent field margins were assessed for 59 maize, 66 beet and 67 spring oilseed rape sites. Fields were split into halves, one being sown with a GMHT crop and the other with the equivalent conventional non-GMHT crop. Margin vegetation was recorded in three components of the field margins. Most differences were in the tilled area, with fewer smaller effects mirroring them in the verge and boundary. In spring oilseed rape fields, the cover, flowering and seeding of plants were 25%, 44% and 39% lower, respectively, in the GMHT uncropped tilled margins. Similarly, for beet, flowering and seeding were 34% and 39% lower, respectively, in the GMHT margins. For maize, the effect was reversed, with plant cover and flowering 28% and 67% greater, respectively, in the GMHT half. Effects on butterflies mirrored these vegetation effects, with 24% fewer butterflies in margins of GMHT spring oilseed rape. The likely cause is the lower nectar supply in GMHT tilled margins and crop edges. Few large treatment differences were found for bees, gastropods or other invertebrates. Scorching of vegetation by herbicide-spray drift was on average 1.6% on verges beside conventional crops and 3.7% beside GMHT crops, the difference being significant for all three crops.

Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. II. Within-field epigeal and aerial arthropods.

The effects of the management of genetically modified herbicide-tolerant (GMHT) crops on the abundances of aerial and epigeal arthropods were assessed in 66 beet, 68 maize and 67 spring oilseed rape sites as part of the Farm Scale Evaluations of GMHT crops. Most higher taxa were insensitive to differences between GMHT and conventional weed management, but significant effects were found on the abundance of at least one group within each taxon studied. Numbers of butterflies in beet and spring oilseed rape and of Heteroptera and bees in beet were smaller under the relevant GMHT crop management, whereas the abundance of Collembola was consistently greater in all GMHT crops. Generally, these effects were specific to each crop type, reflected the phenology and ecology of the arthropod taxa, were indirect and related to herbicide management. These results apply generally to agriculture across Britain, and could be used in mathematical models to predict the possible long-term effects of the widespread adoption of GMHT technology. The results for bees and butterflies relate to foraging preferences and might or might not translate into effects on population densities, depending on whether adoption leads to forage reductions over large areas. These species, and the detritivore Collembola, may be useful indicator species for future studies of GMHT management.

Responses of plants and invertebrate trophic groups to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

Effects of genetically modified herbicide-tolerant (GMHT) and conventional crop management on invertebrate trophic groups (herbivores, detritivores, pollinators, predators and parasitoids) were compared in beet, maize and spring oilseed rape sites throughout the UK. These trophic groups were influenced by season, crop species and GMHT management. Many groups increased twofold to fivefold in abundance between early and late summer, and differed up to 10-fold between crop species. GMHT management superimposed relatively small (less than twofold), but consistent, shifts in plant and insect abundance, the extent and direction of these effects being dependent on the relative efficacies of comparable conventional herbicide regimes. In general, the biomass of weeds was reduced under GMHT management in beet and spring oilseed rape and increased in maize compared with conventional treatments. This change in resource availability had knock-on effects on higher trophic levels except in spring oilseed rape where herbivore resource was greatest. Herbivores, pollinators and natural enemies changed in abundance in the same directions as their resources, and detritivores increased in abundance under GMHT management across all crops. The result of the later herbicide application in GMHT treatments was a shift in resource from the herbivore food web to the detritivore food web. The Farm Scale Evaluations have demonstrated over 3 years and throughout the UK that herbivores, detritivores and many of their predators and parasitoids in arable systems are sensitive to the changes in weed communities that result from the introduction of new herbicide regimes.

Correlates of colorectal cancer testing in Massachusetts men and women.

BACKGROUND: Colorectal cancer (CRC) is a leading cause of cancer-related death. Although CRC screening can reduce CRC mortality, it is underutilized. We examined the association between personal and health care characteristics and CRC testing, defined as being current on any test that meets CRC screening guidelines. METHODS: The current investigation relies on questionnaire data from the 1999 Massachusetts Behavioral Risk Factor Surveillance System and a CRC call-back survey of 869 Behavioral Risk Factor Surveillance System participants age 50 and older. Multivariate logistic regression was used to identify predictors of CRC testing. All analyses were stratified by gender. RESULTS: Men were more likely than women to be currently tested for CRC. Physician recommendation for testing was strongly associated with testing among men and women, but among those with a recommendation, men were more likely to be tested than women. Older age, usually having an annual check-up, and HMO membership were associated with CRC testing among men and women. Perceived high risk of CRC was more strongly associated with testing among men, while other cancer screening was more strongly associated with testing among women. CONCLUSIONS: There are important gender differences in the prevalence of CRC testing and in factors associated with testing. Research into understanding gender differences related to compliance with physician recommendations is warranted.

Tobacco use among adults with disabilities in Massachusetts.

OBJECTIVES: To examine the characteristics of smoking among adults with disabilities in Massachusetts. DESIGN: Data were obtained from the 1996-1999 Massachusetts Behavioral Risk Factor Surveillance System, a random digit dial telephone survey. Respondents reporting use of special equipment or a limitation caused by impairment or health problem were classified as having a disability. Adults with disabilities were further classified by level, based on need for assistance, and type of disability. Logistic regression models were used to assess the association between disability status and smoking. SETTING AND PARTICIPANTS: Random sample of non-institutionalised Massachusetts adults, 18 and older, with disabilities (n = 2985) and without disabilities (n = 14 395). MAIN OUTCOME MEASURES: Smoking status, intensity, and factors related to quitting. RESULTS: Compared to those without disabilities, adults with disabilities were more likely to have ever smoked (odds ratio (OR) 1.42, 95% confidence interval (CI) 1.25 to 1.61) and to be current smokers (OR 1.52, 95% CI 1.32 to 1.76). Smoking rates varied by type of disability. Among current smokers, adults with disabilities smoked more cigarettes per day (OR 1.65, 95% CI 1.31 to 2.16), sooner after waking (OR 1.50, 95% CI 1.13 to 1.99), and were more likely to be advised by a doctor to quit (OR 2.07, 95% CI 1.60 to 2.69). Adults with disabilities who needed assistance were more likely to be planning to quit (OR 1.50, 95% CI 0.99 to 2.26). CONCLUSIONS: There are disparities in smoking rates between adults with and without disabilities. Smoking cessation programmes targeted to the disabled community are needed.

Description of Buckarootrema goodmani n. g., n. sp. (Digenea: Pronocephalidae), a parasite of the freshwater turtle Emydura macquarii (Gray, 1830) (Pleurodira: Chelidae) from Queensland, Australia, and a phylogenetic analysis of the genera of the Pronocephalidae Looss, 1902.

Buckarootrema goodmani n. g., n. sp. is described from the small intestine of the Murray turtle, Emydura macquarii (Gray, 1830), from the vicinity of Warwick, Queensland, Australia. The distinctive taxonomic features include the vitellarium, which consists of 2 compact masses directly anterior to and occasionally overlapping the testes; the uterus with extensive pre- and postovarian coils; intestinal ceca with small, medial diverticula that terminate anterior to or at the anterior margin of the testes; a comma-shaped cirrus sac with both internal and external seminal vesicles. Phylogenetic systematic analysis of the genera of the Pronocephalidae including Buckarootrema and Notopronocephalus, the only other genus of pronocephalids reported from Australian freshwater turtles, indicates that Buckarootrema is the sister taxon of Neopronocephalus and Notopronocephalus is the sister group of the rest of the Pronocephalinae.

Functional expression and characterization of the cytoplasmic aminopeptidase P of Caenorhabditis elegans.

Aminopeptidase P (AP-P; X-Pro aminopeptidase; EC 3.4.11.9) cleaves the N-terminal X-Pro bond of peptides and occurs in mammals as both cytosolic and plasma membrane forms, encoded by separate genes. In mammals, the plasma membrane AP-P can function as a kininase, but little is known about the physiological role of the cytosolic enzyme. The C. elegans genome contains a single gene encoding AP-P (W03G9.4), analysis of which predicts regions displaying high levels of amino-acid sequence homology between the predicted gene product and mammalian cytoplasmic AP-P, with the absolute conservation of key catalytic residues. The sequence of an EST (yk91g4), comprising the open reading frame of W03G9.4, confirmed the predicted genomic structure of the gene and the prediction that W03G9.4 codes for a nonsecreted protein with a molecular mass of 68 kDa. Nematodes transformed with a promoter reporter construct, W03G9.4:GFP, showed high levels of fluorescence in the intestine of larvae and adult hermaphrodites, indicating that the intestine is a major site of W03G9.4 expression. yk91g4 tagged with a hexahistidine and DLYDDDDK peptide epitope was expressed in Escherichia coli to yield, after affinity purification, a recombinant protein with a molecular mass of 71 kDa. The recombinant W03G9.4 removed the N-terminal amino acid from bradykinin (RPPGFSPFR), a Caenorhabditis elegans neuropeptide (KPSFVRFamide) and Lem Trp 1 (APSGFLGVRamide), but did not display activity towards angiotensin I (NRVYIHPFHL), des-Arg bradykinin and AF1 (KNEFIRFamide). The activity towards bradykinin was inhibited by EDTA and 1, 10 phenanthroline, as expected for a metalloenzyme, and also by apstatin (IC50, 1 microM), a selective inhibitor of mammalian AP-P. A Km of 45 microM and an optimum pH of 7-8 was observed with bradykinin as the substrate. The activity of the nematode AP-P, like its mammalian counterparts, was strongly influenced by metal ions, with Co2+, Mn2+ and Zn2+ all inhibiting the hydrolysis of bradykinin. We conclude that W03G9.4 codes for a cytoplasmic AP-P with very similar enzymatic properties to those of mammalian AP-P, and we suggest that the enzyme has a physiological role in the intracellular hydrolysis of proline-containing peptides absorbed from the lumen of the intestine.

The stage-regulated expression of Leishmania mexicana CPB cysteine proteases is mediated by an intercistronic sequence element.

The tandemly arranged CPB genes of Leishmania mexicana are polycistronically transcribed and encode cysteine proteases that are differentially stage-specific; CPB1 and CPB2 are expressed predominantly in metacyclics, whereas CPB3-CPB18 are expressed mainly in amastigotes. The mechanisms responsible for this differential expression have been studied via gene analysis and re-integration of individual CPB genes, and variants thereof, into a CPB-deficient parasite mutant. Comparison of the nucleotide sequences of the repeat units of CPB1 and CPB2 with CPB2.8 (typical of CPB3-CPB18) revealed two major regions of divergence as follows: one of 258 base pairs (bp) corresponding to the C-terminal extension of CPB2.8; another, designated InS, of 120 bp, with insertions totaling 57 bp, localized to the intercistronic region downstream of CPB1 and CPB2. Cell lines expressing CPB2.8 or CPB2 with the 3'-untranslated region and intercistronic sequence of CPB2.8 showed up-regulation in amastigotes. Conversely, metacyclic-specific expression occurred with CPB2 or CPB2.8 with the 3'-untranslated region and intercistronic sequence of CPB2. Moreover, the InS down-regulated expression in amastigotes of a reporter gene integrated into the CPB locus. It is proposed that the InS mediates metacyclic-specific stage-regulated expression of CPB by affecting the maturation of polycistronic pre-mRNA. This is the first well defined cis-regulatory element implicated in post-transcriptional stage-specific gene expression in Leishmania.

Support for condom availability and needle exchange programs among Massachusetts adults, 1997.

This study was conducted to determine whether demographic factors, variables related to HIV risk status, or personal attitudes predicted public support for condom availability programs in high schools and needle exchange programs. Data for these analyses were collected from the 1997 Massachusetts Behavioral Risk Factor Surveillance System (BRFSS) among adults aged 18-64. Overall, 79% of Massachusetts adults aged 18-64 supported condom availability programs, and 60% supported needle exchange programs. Younger age was the strongest demographic predictor of support for condom availability, and higher socioeconomic status was the strongest predictor of support for needle exchange programs. Support for both programs was weakly associated with personal HIV risk status but strongly associated with positive attitudes toward teaching about HIV in schools and advising sexually active teens to use condoms. Our data suggest that there is broad-based public support for implementation of condom availability and needle exchange programs as tools for HIV prevention.