bluuebunny/crossref_metadata_2025_split huggingface dataset:
Consumer‐specific responses to riverine subsidy pulses in a riparian arthropod assemblage
Authors: PAETZOLD ACHIM , BERNET JACQUELINE F. , TOCKNER KLEMENT 
Published: May 2006

Summary1. Aquatic resource fluxes from streams can provide significant subsidies for riparian consumers. Because aquatic resource fluxes can be highly variable in space and time, the subsidy efficiency (i.e. transfer to the recipient food web) is controlled by the short‐term aggregative response of riparian consumers.2. Field manipulations of stream‐derived invertebrate prey subsidies were used to examine specific aggregative responses of ground‐dwelling arthropods to riverine subsidy pulses in a braided‐river (Tagliamento River, NE Italy). Subsidy manipulation comprised short‐term reductions of natural stream‐derived subsidies and increased subsidies of stream‐derived invertebrate prey during four seasons.3. We hypothesised that specific aggregative responses of riparian arthropods depend on their specialisation on aquatic insects which was inferred from stable isotope analysis. Natural riverine subsidy sources including aquatic insect emergence and surface‐drifting organisms were quantified.4. Arthropods responded significantly with a reduction in abundance by 51%, at reduced subsidies and an increase by 110% at increased subsidies, when averaged over all seasons. Different arthropod taxa responded differently to subsidy manipulations in relation to their specialisation on aquatic subsidies: ground beetles with a diet consisting predominantly of aquatic insects responded only to subsidy reductions, indicating that their local abundance was not limited by natural stream‐derived subsidies; lycosid spiders with a partly aquatic diet showed no significant response; and ants, although relying on a terrestrial diet, responded positively to added stream‐derived invertebrate prey, indicating that stranding of surface‐drifting terrestrial invertebrates represented an important subsidy pathway.5. Ground beetles and lycosid spiders were seasonally separated in their use of aquatic subsidies. Results indicate that the life‐history characteristics of riparian consumers can control the subsidy efficiency for the recipient community. By the effective uptake of pulsed riverine‐derived subsidies, riparian arthropods can enhance the transfer of riverine food sources to the riparian food web.
Elevated CO2 and tree fecundity: the role of tree size, interannual variability, and population heterogeneity
Authors: LADEAU SHANNON L. , CLARK JAMES S. 
Published: May 2006

AbstractLong‐term population effects of changes in atmospheric CO2 will be largely determined by reproductive effort. Our research objectives were to quantify variability in seed production and rate of maturation among individual Pinus taeda L. (Pinaceae) trees growing in elevated CO2 (ambient plus 200 μL L−1) since 1996. Estimating tree fecundity in nature is frustrated by the difficulty of counting seeds from individual trees and the need for long‐term data. We have used a hierarchical Bayes approach to model individual tree fecundity, accounting for the complexity of experimentation in a natural setting over multiple years. The study presented here demonstrates large variability in natural fecundity rates and contributes to our understanding of how both interannual variation and population heterogeneity influence elevated CO2 effects. We found that trees growing under elevated CO2 matured earlier and produced more seeds and cones per unit basal area than ambient grown trees. By 2004, trees grown in high CO2 had produced an average 300 more seeds per tree than ambient grown trees. Although there was a trend toward decreasing mean CO2 effect (difference in fecundity between elevated and ambient treatments) over time, the hierarchical analysis indicates that this decrease comes from the emergence of a few highly fecund ambient grown trees by 2002, rather than acclimation or downregulation among the fumigated trees. The most important effect of increased CO2 in forest ecosystems may be the increase in fecundity reported here. Although biomass responses can sometimes be large, the increase in fecundity can have long‐term impacts on forest dynamics that transcend the current generation.
Estimates of soil respiration and net primary production of three forests at different succession stages in South China
Authors: YAN JUNHUA , WANG YINGPING , ZHOU GUOYI , ZHANG DEQIANG 
Published: May 2006

AbstractSoil respiration (heterotropic and autotropic respiration, Rg) and aboveground litter fall carbon were measured at three forests at different succession (early, middle and advanced) stages in Dinghushan Biosphere Reserve, Southern China. It was found that the soil respiration increases exponentially with soil temperature at 5 cm depth (Ts) according to the relation Rg=a exp(bTs), and the more advanced forest community during succession has a higher value of a because of higher litter carbon input than the forests at early or middle succession stages. It was also found that the monthly soil respiration is linearly correlated with the aboveground litter carbon input of the previous month. Using measurements of aboveground litter and soil respiration, the net primary productions (NPPs) of three forests were estimated using nonlinear inversion. They are 475, 678 and 1148 g C m−2 yr−1 for the Masson pine forest (MPF), coniferous and broad‐leaf mixed forest (MF) and subtropical monsoon evergreen broad‐leaf forest (MEBF), respectively, in year 2003/2004, of which 54%, 37% and 62% are belowground NPP for those three respective forests if no change in live plant biomass is assumed. After taking account of the decrease in live plant biomass, we estimated the NPP of the subtropical MEBF is 970 g C m−2 yr−1 in year 2003/2004. Total amount of carbon allocated below ground for plant roots is 388 g C m−2 yr−1 for the MPF, 504 g C m−2 yr−1 for the coniferous and broad‐leaf MF and 1254 g C m−2 yr−1 for the subtropical MEBF in 2003/2004. Our results support the hypothesis that the amount of carbon allocation belowground increases during forest succession.
Downy mildew (Plasmopara viticola) epidemics on grapevine under climate change
Authors: FRANCESCA SALINARI , SIMONA GIOSUÈ , FRANCESCO NICOLA TUBIELLO , ANDREA RETTORI , VITTORIO ROSSI , FEDERICO SPANNA , CYNTHIA ROSENZWEIG , MARIA LODOVICA GULLINO 
Published: May 2006

AbstractAs climate is a key agro‐ecosystem driving force, climate change could have a severe impact on agriculture. Many assessments have been carried out to date on the possible effects of climate change (temperature, precipitation and carbon dioxide concentration changes) on plant physiology. At present however, likely effects on plant pathogens have not been investigated deeply. The aim of this work was to simulate future scenarios of downy mildew (Plasmopara viticola) epidemics on grape under climate change, by combining a disease model to output from two general circulation models (GCMs). Model runs corresponding to the SRES‐A2 emissions scenario, characterized by high projections of both population and greenhouse gas emissions from present to 2100, were chosen in order to investigate impacts of worst‐case scenarios, among those currently available from IPCC. Three future decades were simulated (2030, 2050, 2080), using as baseline historical series of meteorological data collected from 1955 to 2001 in Acqui Terme, an important grape‐growing area in the north‐west of Italy. Both GCMs predicted increase of temperature and decrease of precipitation in this region. The simulations obtained by combining the disease model to the two GCM outputs predicted an increase of the disease pressure in each decade: more severe epidemics were a direct consequence of more favourable temperature conditions during the months of May and June. These negative effects of increasing temperatures more than counterbalanced the effects of precipitation reductions, which alone would have diminished disease pressure. Results suggested that, as adaptation response to future climate change, more attention would have to be paid in the management of early downy mildew infections; two more fungicide sprays were necessary under the most negative climate scenario, compared with present management regimes. At the same time, increased knowledge on the effects of climate change on host–pathogen interactions will be necessary to improve current predictions.
The role of TGF‐β in mice infected with Heligmosomoides polygyrus
Authors: DOLIGALSKA M. , RZEPECKA J. , DRELA N. , DONSKOW K. , GERWEL‐WRONKA M. 
Published: May 2006

SUMMARY Hyporesponsiveness induced by Heligmosomoides polygyrus was quantified and the relationship between TGF‐β and inflammation was identified in BALB/c mice. The immune response and pathological changes modified by neutralization of TGF‐β were characterized in vivo. Nine and twelve days following infection, BALB/c mice were injected intraperitoneally with anti‐TGF‐β (1,2,3) antibodies, isotype control antibodies or isosmotic solution. We assessed both Th1 and Th2 related cytokines production ex vivo and in vitro, IgA, the number of CD4+ cells, and eosinophils in the lamina propria and the villus : crypt ratio in the small intestine 6 weeks after infection. The pattern of cytokine production differed in the intestine, peritoneal fluid and serum. In mice infected with H. polygyrus the concentrations of IL‐5, IL‐12, TNF‐α and IL‐10 were raised in the intestine, but in serum the level of cytokines was diminished below the value observed in uninfected mice. The neutralization of TGF‐β converted the pattern of immune response induced by H. polygyrus. The elevation of cytokines in serum coincided with the reduction of cytokine concentration in the intestine or peritoneum. Neutralization of TGF‐β restored infiltration of eosinophils into the lamina propria of the intestine despite the low level of IL‐5. We conclude that H. polygyrus infection suppresses the immune response through pathways involving TGF‐β production or activity and that the Th2 related immune response was not affected by neutralization.
Variance Estimation for Generalized Entropy and Atkinson Inequality Indices: the Complex Survey Data Case*
Authors: Biewen Martin , Jenkins Stephen P. 
Published: May 2006

AbstractWe derive the sampling variances of generalized entropy and Atkinson indices when estimated from complex survey data, and show how they can be calculated straightforwardly using widely available software. We also show that, when the same approach is used to derive variance formulae for the independent and identically distributed case, it leads to estimators that are simpler than those proposed before. Both cases are illustrated with a comparison of income inequality in Britain and Germany.
Character evolution in the orbital region of the Afrotheria
Authors: Cox P. G. 
Published: May 2006

AbstractThe orbit or eye socket is a highly plastic area of the mammalian skull. There is significant variation within and between the different mammalian orders in the size and position of the bones and foramina that contribute to this region. For this reason, orbital characters are often used in attempts to determine the relationships of the various mammalian groups. This study describes the orbital region of the Afrotheria, the proposed group of endemic African mammals that comprises the paenungulates (elephants, manatees and dugongs, and hyraxes), elephant‐shrews, aardvarks, golden moles and tenrecs. Evolution within the Afrotherian orbit is then explored by scoring 19 orbital characters in each Afrotherian genus, and plotting the character state changes on to previously existing phylogenies of the Afrotheria. These phylogenies were all produced from recent molecular work. It was found that there is a great deal of variation in the orbital region within the Afrotheria, most notably in the size of the lacrimal and its contacts with other bones, the appearance of the palatine in the orbit and the structure of the zygomatic arch. Overall, orbital characters strongly supported an elephant‐hyrax clade over the more traditional grouping of elephants and sirenians (Tethytheria) within the paenungulates. There was also support for a monophyletic Tenrecoidea (a clade of tenrecs plus golden moles). Additionally, it was shown that there is a great deal of variation in the orbital region among the genera of the Tenrecidae and the Macroscelididae.
Human cancers and the FHIT gene
Authors: AGRAWAL Suraksha , MOORCHUNG Nikhil , PRIYA Padma , KAPOOR VK 
Published: May 2006

AbstractThe FHIT gene is a relatively newly discovered tumor suppressor gene, which is located on the chromosome 3p14.2. The gene encompasses the FRA3B fragile site. The gene has been implicated in the pathogenesis of various carcinomas, particularly cancers of the stomach and oral squamous cell carcinomas. The protein encoded by the gene bears a significant homology to a group of proteins that have a histidine triad motif, designated HIT proteins. The function of the protein remains essentially unknown. Loss of heterozygosity and microsatellite instability are responsible for FHIT gene alterations. A mutation in a gene will invariably give abnormal transcripts and contribute to the pathogenesis of cancer. A better understanding of FHIT mutations will also help us to understand the pathogenesis of the multistep process of carcinogenesis. Therapeutic potentials of Fhit can also be explored. Replacement of FHIT cDNA in human cancer cell lines has resulted in the suppression of tumor growth. This opens the possibility of therapeutic potentials using recombinant vectors carrying the FHIT gene.
Oxidation of fugitive methane in ground water linked to bacterial sulfate reduction
Authors: Van Stempvoort Dale , Maathuis Harm , Jaworski Ed , Mayer Bernhard , Rich Kathleen 
Published: May 2006

AbstractWhen fugitive methane migrates upward along boreholes of oil and gas wells, it may migrate into shallow ground water or pass through overlying soil to the atmosphere. Prior to this study, there was little information on the fate of fugitive methane that migrates into ground water. In a field study near Lloydminster, Alberta, Canada, we found hydrogeochemical evidence that fugitive methane from an oil well migrated into a shallow aquifer but has been attenuated by dissimilatory bacterial sulfate reduction at low temperature (∼5°C) under anaerobic conditions. Evidence includes spatial and temporal trends in concentrations of methane and sulfate in ground water and associated trends in concentrations of bicarbonate and sulfide. Within 10 m of the oil well, sulfate concentrations were low, and sulfate was enriched in both 34S and 18O. Sulfate concentrations had a strong positive correlation with δ13C values of bicarbonate, and sulfide was depleted in 34S compared to sulfate. These data indicate that bacterial sulfate reduction occurred near the production well. Near the oil well, elevated concentrations of bicarbonate were observed, and the bicarbonate was depleted in 13C. Modeling indicates that the main source of this excess 13C‐depleted bicarbonate is oxidized methane. In concert with the sulfate concentration and isotope data, these results support an interpretation that in situ bacterial oxidation of methane has occurred, linked to bacterial sulfate reduction. Bacterial sulfate reduction may play a major role in bioattenuation of fugitive natural gas in ground water in western Canada.
The Annular Response to Tropical Pacific SST Forcing
Authors: Li Shuanglin , Hoerling Martin P. , Peng Shiling , Weickmann Klaus M. 
Published: May 2006

Abstract
The leading pattern of Northern Hemisphere winter height variability exhibits an annular structure, one related to tropical west Pacific heating. To explore whether this pattern can be excited by tropical Pacific SST variations, an atmospheric general circulation model coupled to a slab mixed layer ocean is employed. Ensemble experiments with an idealized SST anomaly centered at different longitudes on the equator are conducted. The results reveal two different response patterns—a hemispheric pattern projecting on the annular mode and a meridionally arched pattern confined to the Pacific–North American sector, induced by the SST anomaly in the west and the east Pacific, respectively. Extratropical air–sea coupling enhances the annular component of response to the tropical west Pacific SST anomalies.
A diagnosis based on linear dynamical models suggests that the two responses are primarily maintained by transient eddy forcing. In both cases, the model transient eddy forcing response has a maximum near the exit of the Pacific jet, but with a different meridional position relative to the upper-level jet. The emergence of an annular response is found to be very sensitive to whether transient eddy forcing anomalies occur within the axis of the jet core. For forcing within the jet core, energy propagates poleward and downstream, inducing an annular response. For forcing away from the jet core, energy propagates equatorward and downstream, inducing a trapped regional response. The selection of an annular versus a regionally confined tropospheric response is thus postulated to depend on how the storm tracks respond. Tropical west Pacific SST forcing is particularly effective in exciting the required storm-track response from which a hemisphere-wide teleconnection structure emerges.
Composite Analysis of Winter Cyclones in a GCM: Influence on Climatological Humidity
Authors: Bauer Mike , Del Genio Anthony D. 
Published: May 2006

Abstract
The role of midlatitude baroclinic cyclones in maintaining the extratropical winter distribution of water vapor in an operational global climate model is investigated. A cyclone identification and tracking algorithm is used to compare the frequency of occurrence, propagation characteristics, and composite structure of 10 winters of storms in the Goddard Institute for Space Studies general circulation model (GCM) and in two reanalysis products. Cyclones are the major dynamical source of water vapor over the extratropical oceans in the reanalyses. The GCM produces fewer, generally weaker, and slower-moving cyclones than the reanalyses and is especially deficient in storms associated with secondary cyclogenesis. Composite fields show that GCM cyclones are shallower and drier aloft than those in the reanalyses and that their vertical structure is less tilted in the frontal region because of the GCM’s weaker ageostrophic circulation. This is consistent with the GCM’s underprediction of midlatitude cirrus. The GCM deficiencies do not appear to be primarily due to parameterization errors; the model is too dry despite producing less storm precipitation than is present in the reanalyses and in an experimental satellite precipitation dataset, and the weakness and shallow structure of GCM cyclones is already present at storm onset. These shortcomings may be common to most climate GCMs that do not resolve the mesoscale structure of frontal zones, and this may account for some universal problems in climate GCM midlatitude cloud properties.
Centered Composite Analysis of Variations Associated with the Madden–Julian Oscillation
Authors: Weare Bryan C. 
Published: May 2006

Abstract
Centered composite analysis is described and applied to gain a better understanding of the initial phases of the Madden–Julian oscillation (MJO). Centered composite analysis identifies the dates and central locations of key events. The elements of the composite means are centered on these central locations before averages are calculated. In this way much of the spatial fuzziness, which is inherent in traditional composite analysis, is removed. The results for the MJO, based on MJO-filtered outgoing longwave radiation for the reference data and 40-yr ECMWF Re-Analysis (ERA-40) and NCEP–NCAR reanalysis products for the composites, show highly significant composites of unfiltered data for not only zero lag, but also lags back to 20 days before the target events. These composites identify propagating patterns of surface pressure, upper- and lower-troposphere zonal winds, surface temperature, and 850-hPa specific humidity associated with MJO convective events in the Indian Ocean. The propagation characteristics of important features, especially surface pressure, differ substantially for MJO convective anomalies centered over the Indian or western Pacific Oceans. This suggests that distinctly different mechanisms may be dominant in these two regions, and that many earlier analyses may be mixing properties of the two.
Conserved genes in a path from commensalism to pathogenicity: comparative phylogenetic profiles of Staphylococcus epidermidis RP62A and ATCC12228
Authors: Wei Wu , Cao ZhiWei , Zhu Yu-Li , Wang XiaoJing , Ding GuoHui , Xu Hao , Jia PeiLin , Qu Di , Danchin Antoine , Li YiXue 
Published: May 2006

Abstract

Background

Staphylococcus epidermidis, long regarded as an innocuous commensal bacterium of the human skin, is the most frequent cause of nosocomial infections associated with implanted medical devices. This conditional pathogen provides a model of choice to study genome landmarks correlated with the transition between commensalism and pathogenicity. Traditional investigations stress differences in gene content. We focused on conserved genes that have accumulated small mutation differences during the transition.

Results
A comparison of strain ATCC12228, a non-biofilm forming, non-infection associated strain and strain RP62A, a methicillin-resistant biofilm clinical isolate, revealed consistent variation, mostly single-nucleotide polymorphisms (SNPs), in orthologous genes in addition to the previously investigated global changes in gene clusters. This polymorphism, scattered throughout the genome, may reveal genes that contribute to adaptation of the bacteria to different environmental stimuli, allowing them to shift from commensalism to pathogenicity. SNPs were detected in 931 pairs of orthologs with identical gene length, accounting for approximately 45% of the total pairs of orthologs. Assuming that non-synonymous mutations would mark recent evolution, and hence be associated to the onset of the pathogenic process, analysis of ratios of non-synonymous SNPs vs synonymous SNPs suggested hypotheses about possible pathogenicity determinants. The N/S ratios for virulence factors and surface proteins differed significantly from that of average SNPs. Of those gene pairs, 40 showed a disproportionate distribution of dN vs dS. Among those, the presence of the gene encoding methionine sulfoxide reductase suggested a possible involvement of reactive oxygen species. This led us to uncover that the infection associated strain was significantly more resistant to hydrogen peroxide and paraquat than the environmental strain. Some 16 genes of the list were of unknown function. We could suggest however that they were likely to belong to surface proteins or considered in priority as important for pathogenicity.

Conclusion
Our study proposed a novel approach to identify genes involved in pathogenic processes and provided some insight about the molecular mechanisms leading a commensal inhabitant to become an invasive pathogen.