bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Conductivity of Gas‐Pressure‐Sintered Silicon Nitride
Authors: Hirosaki Naoto , Okamoto Yusuke , Ando Motohide , Munakata Fumio , Akimune Yoshio
Published: September 2005

Si3N4 with high thermal conductivity (120 W/(m.K)) was developed by promoting grain growth and selecting a suitable additive system in terms of composition and amount. β‐Si3N4 doped with Y2O3‐Nd2O3 (YN system) or Y2O3‐A12O3 (YA system) was sintered at 1700°‐2000°C. Thermal conductivity increased with increased sintering temperature because of decreased two‐grain junctions, as a result of grain growth. The effect of the additive amount on thermal conductivity with the YN system was rather small because increased additive formed multigrain junctions. On the other hand, with the YA system, thermal conductivity considerably decreased with increased additive amount because the aluminum and oxygen in the YA system dissolved into β‐Si3N4 grains to form a β‐SiAlON solid solution, which acted as a point defect for phonon scattering. The key processsing parameters for high thermal conductivity of Si3N4 were the sintering temperature and additive composition.
Kinetics and Mechanisms of Hydrothermal Synthesis of Barium Titanate
Authors: Eckert James O. , Hung‐Houston Catherine C. , Gersten Bonnie L. , Lencka Malgorzata M. , Riman Richard E.
Published: September 2005

Reaction mechanisms for the hydrothermal synthesis of barium titanate are evaluated. Feedstocks of barium hydroxide octahydrate and anatase titania are reacted for varying durations (1–72 h) to provide intermediate‐stage samples for characterization by transmission electron microscopy/ energy‐dispersive spectroscopy (TEM/EDS), X‐ray diffractometry (XRD), and inductively coupled plasma spectroscopy (ICP). Quantitative evaluation of the extent of reaction by ICP and XRD methods permits the analysis of data with the Johnson‐Mehl‐Avrami equation. This analysis reveals two reaction‐rate regimes. Kinetic analysis, based on reaction progress, yields insight into the first reaction‐rate regime but is inconclusive in the analysis of the second reaction‐rate regime. In the first regime, at the early stage of barium titanate formation, a dissolution‐precipitation mechanism dominates. In contrast, in the second regime, at longer reaction times, an in‐situ transformation mechanism is probably dominant. However, multiple reaction mechanisms (e.g., in‐situ transformation and dissolution‐precipitation) may be competing for rate control. Alternatively, dissolution‐precipitation may be the dominant mechanism throughout the barium titanate synthesis, with nucleation and growth controlling the first regime and dissolution rate controlling the second regime.
Anaesthetic management of placenta accreta: use of a pre‐operative high and low suspicion classification*
Authors: Weiniger C. F. , Elram T. , Ginosar Y. , Mankuta D. , Weissman C. , Ezra Y.
Published: September 2005

Placenta accreta may be suspected prior to surgery, but the actual diagnosis is only confirmed at surgery. This prospective and observational study was performed to assess whether preparations should be made for potential massive blood loss prior to Caesarean surgery in all patients with suspected placenta accreta. Patients were classified as high or low suspicion for placenta accreta based on ultrasonography and clinical factors. Among 28 suspected cases of placenta accreta, diagnosis was confirmed at surgery in 50% (12/17 high and 2/11 low suspicion) cases. Hysterectomy was only performed in the 12 high suspicion patients with placenta accreta (p < 0.001). High suspicion patients required more blood transfusions: mean(SD) 6.5 (7.0) units vs 1.09 (1.1) units, p = 0.017. Anaesthetists should be prepared for major haemorrhage in all cases of suspected placenta accreta, although use of a system to grade level of suspicion may identify those at greater risk.
Airway rescue in acute upper airway obstruction using a ProSeal™ Laryngeal mask airway and an Aintree Catheter™: a review of the ProSeal™ Laryngeal mask airway in the management of the difficult airway
Authors: Cook T. M. , Silsby J. , Simpson T. P.
Published: September 2005

We report the successful use of a ProSeal™ Laryngeal mask airway (PLMA) to rescue the airway when emergency tracheal intubation and ventilation of the lungs were impossible after haemorrhage into the neck following carotid endarterectomy, despite evacuation of the clot. The airway was re‐established after placement of a PLMA. Fibreoptic examination of the airway revealed severe supraglottic swelling compromising airway patency. An Aintree catheter was placed in the trachea under fibreoptic guidance and a tracheal tube railroaded over this. The use of the PLMA in seven cases of difficult airway management and 11 cases of airway rescue is reviewed. Use of the PLMA was associated with high levels of success, often rescuing the airway when other techniques had failed. No complications of use of the PLMA were reported in these cases. The PLMA appears to be a useful device to assist in management of the difficult airway and for airway rescue. Potential advantages over the classic laryngeal mask airway include improved airway seal and reduced risk of aspiration. The gum elastic bougie‐guided insertion technique is recommended when the PLMA is used for airway rescue.
The pharmaco‐economics of peri‐operative statin therapy
Authors: Biccard B. M. , Sear J. W. , Foëx P.
Published: September 2005

We analysed the pharmaco‐economics of the prospective peri‐operative studies of statin administration for major elective vascular surgery, using the NHS reference costs for 2004. This analysis suggests that peri‐operative statin therapy for patients undergoing vascular surgery may present the most cost‐effective use of statin therapy yet described, with a number‐needed‐to‐treat of 15 and almost 60% of the total cost of atorvastatin therapy recovered through a reduction in peri‐operative adverse events.
A prospective, randomised controlled trial comparing the efficacy of pre‐oxygenation in the 20° head‐up vs supine position*
Authors: Lane S. , Saunders D. , Schofield A. , Padmanabhan R. , Hildreth A. , Laws D.
Published: September 2005

We investigated whether positioning patients undergoing general anaesthesia for cholecystectomy in a 20° head‐up position, as opposed to supine, improved the efficacy of 3 min of standard pre‐oxygenation via a circle breathing system. Following pre‐oxygenation, patients received a standard induction of anaesthesia and the apnoea time (from administration of rocuronium to the arterial oxygen saturation to fall to 95%) was recorded. Mean (95% CI) apnoea time was 386 (343–429) s in the 20° head‐up position (n = 17) vs 283 (243–322) s in the supine position (n = 18; p = 0.002). Pre‐oxygenation is significantly more efficacious and by inference more efficient in the 20° head‐up position than in the supine position.
Implementation of a tight glycaemic control protocol using a web‐based insulin dose calculator
Authors: Thomas A. N. , Marchant A. E. , Ogden M. C. , Collin S.
Published: September 2005

We describe the implementation of a glucose control protocol supported by a web‐based insulin dose calculator in a 16‐bedded intensive care unit. The protocol was introduced and then modified after 15 months' use. Glucose concentrations were retrospectively reviewed and compared for the 9‐month period before introduction of the protocol (288 patients), for 15 months after its introduction (502 patients) and for a further 5 months after its modification to increase insulin dose (101 patients). The mean (SD) blood glucose concentrations decreased from 7.3 (1.8) mmol.l−1 to 6.6 (1.6) mmol.l−1 and then to 6.2 (1.3) mmol.l−1. The proportion of values < 8.0 mmol.l−1 increased from 69% to 81% and then to 89%. Blood glucose concentrations were increased by the use of intravenous nutrition and by vasoactive drugs but not by the administration of propofol. The odds ratio [95% CI] for death for glucose values > 8.0 mmol.l−1 was 2.10 [1.19–3.73] compared to values < 6.1 mmol.l−1. However, patient mortality remained constant during the study. Glycaemic control was improved outside a research setting using a protocol supported by a web‐based insulin dose calculator.
Characterization of HIV-1 Gag-specific T cell responses in chronically infected Indian population
Authors: Kaushik S , Vajpayee M , Wig N , Seth P
Published: September 2005

India is at the epicentre of the global HIV/AIDS epidemic in South-east Asia, predominated by subtype C infections. It is important to characterize HIV-1-specific T cell responses in this particular population with the aim of identifying protective correlates of immunity to control HIV-1 infection. In this study, we performed a comprehensive analysis of the breadth and magnitude of T cell responses directed at HIV-1 subtype C Gag, one of the most conserved HIV-1 proteins. The study population consisted of antiretroviral naive, chronic HIV-1 subtype C-infected individuals at various stages of infection. We used recent advanced techniques such as enzyme-linked immunospot (ELISPOT) assay and intracellular cytokine staining to quantify the total CD4+ and CD8+ T cell response to HIV-1 gag at single peptide level, regardless of HLA haplotype of the infected individual. The p24-Gag was identified as the most frequently recognized subunit protein with the greatest magnitude of CD4+ and CD8+ T cell responses. Stronger and broader CD8 T cell responses were recognized, contrasting with the weaker and narrower CD4 T cell responses with regard to Gag protein subunits. The magnitude of the HIV-specific interferon (IFN)-γ responses was observed to be higher than the corresponding interleukin (IL)-2 response, indicating the persistence of antigenic load in chronically infected Indian population due to the probable dysfunction of HIV-specific, IFN-γ-secreting CD8 T cells in absence of IL-2 help.
Differences in temperature, organic carbon and oxygen consumption among lowland streams
Authors: SAND‐JENSEN KAJ , PEDERSEN NIELS L.
Published: September 2005

1. Temperature, organic carbon and oxygen consumption were measured over a year at 13 sites in four lowlands streams within the same region in North Zealand, Denmark with the objectives of determining: (i) spatial and seasonal differences between open streams, forest streams and streams with or without lakes, (ii) factors influencing the temperature dependence of oxygen consumption rate, (iii) consequences of higher temperature and organic content in lake outlets on oxygen consumption rate, and (iv) possible consequences of forecasted global warming on degradation of organic matter.

2. High concentrations of easily degradable dissolved (DOC) and particulate organic carbon (POC) were found in open streams downstream of plankton‐rich lakes, while high concentrations of recalcitrant DOC were found in a forest brook draining a forest swamp. Concentrations of predominantly recalcitrant POC and DOC were low in a groundwater‐fed forest spring. Overall, DOC concentration was two to 18 times higher than POC concentrations.

3. Oxygen consumption rate at 20 °C was higher during summer than winter, higher in open than shaded streams and higher in lake outlets than inlets. Rate was closely related to concentrations of chlorophyll and POC but not to DOC. The ratio of oxygen consumption rate to total organic concentrations (DOC + POC), serving as a measure of organic degradability, was highest downstream of lakes, intermediate in open streams and lowest in forest streams.

4. Temperature coefficients describing the exponential increase of oxygen consumption rate between 4 and 20 °C averaged 0.121 °C−1(Q10of 3.35) in 70 measurements and showed no significant variations between seasons and stream sites or correlations with ambient temperature and organic content.

5. Oxygen consumption rate was enhanced downstream of lakes during summer because of higher temperature and, more significantly, greater concentrations of degradable organic carbon. Oxygen consumption rates were up to seven times higher in the stream with three impoundments than in a neighbouring unshaded stream and 21 times higher than in the groundwater‐fed forest spring.

6. A regional climate model has calculated a dramatic 4–5 °C rise in air temperature over Denmark by 2070–2100. If this is realised, unshaded streams are estimated to become 2–3 °C warmer in summer and winter and 5–7 °C warmer in spring and, thereby, increase oxygen consumption rates at ambient temperature by 30–40% and 80–130%, respectively. Faster consumption of organic matter and dissolved oxygen downstream of point sources should increase the likelihood of oxygen stress of the stream biota and lead to the export of less organic matter but more mineralised nutrients to the coastal waters.
Species richness and food web structure of soil decomposer community as affected by the size of habitat fragment and habitat corridors
Authors: Rantalainen Minna‐Liisa , Fritze Hannu , Haimi Jari , Pennanen Taina , Setälä Heikki
Published: September 2005

While most ecologists agree that the effects of fragmentation on diversity of organisms are predominantly negative and that the scale of fragmentation defines their severity, the role of habitat corridors in mitigating those effects still remains controversial. This ambiguousness rests largely on various difficulties in experimentation, a problem partially solved in the present paper by the use of easily manipulated soil communities. In this 2.5‐year‐long field experiment, we investigated the responses of soil decomposer organisms (from microbes to mesofaunal predators) to habitat fragment size, in the presence or absence of habitat corridors connecting the fragments. The habitat fragments and corridors, composed of forest humus soil, were embedded in mineral soil representing an uninhabitable (or nonpreferred) matrix for the decomposer organisms. The results demonstrate that soil decomposer organisms do respond to changes in their habitat size: the species richness of microarthropods (mites and collembolans) increased as the size of the fragments increased. Especially collembolan species and predatory mites proved to be sensitive to the restricted habitat size, which is suggested to be a consequence of the large proportion of rare species and small and fluctuating population sizes in these groups. Contrary to our expectations, the presence of corridors had no positive effects on species richness or abundance of any of the studied faunas, possibly because of the low quality of the corridors. On the other hand, the biomass of soil fungi increased in the presence of corridors, which apparently provided a preferred pathway for vegetative dispersal of the fungi. Our results indicate that despite their characteristic underground environment, the response of soil decomposer organisms – in particular that of microarthropods – to habitat size is not unlike to that of the larger organisms in aboveground habitats.
Carbon fluxes from a tropical peat swamp forest floor
Authors: Jauhiainen Jyrki , Takahashi Hidenori , Heikkinen Juha E. P. , Martikainen Pertti J. , Vasander Harri
Published: September 2005

A tropical ombrotrophic peatland ecosystem is one of the largest terrestrial carbon stores. Flux rates of carbon dioxide (CO2) and methane (CH4) were studied at various peat water table depths in a mixed‐type peat swamp forest floor in Central Kalimantan, Indonesia. Temporary gas fluxes on microtopographically differing hummock and hollow peat surfaces were combined with peat water table data to produce annual cumulative flux estimates. Hummocks formed mainly from living and dead tree roots and decaying debris maintained a relatively steady CO2 emission rate regardless of the water table position in peat. In nearly vegetation‐free hollows, CO2 emission rates were progressively smaller as the water table rose towards the peat surface. Methane emissions from the peat surface remained small and were detected only in water‐saturated peat. By applying long‐term peat water table data, annual gas emissions from the peat swamp forest floor were estimated to be 3493±316 g CO2 m−2 and less than 1.36±0.57 g CH4 m−2. On the basis of the carbon emitted, CO2 is clearly a more important greenhouse gas than CH4. CO2 emissions from peat are the highest during the dry season, when the oxic peat layer is at its thickest because of water table lowering.
Fertilization of boreal forest reduces both autotrophic and heterotrophic soil respiration
Authors: Olsson Per , Linder Sune , Giesler Reiner , Högberg Peter
Published: September 2005

The boreal forest is expected to experience the greatest warming of all forest biomes, raising concerns that some of the large quantities of soil carbon in these systems may be added to the atmosphere as CO2. However, nitrogen deposition or fertilization has the potential to increase boreal forest production and retard the decomposition of soil organic matter, hence increasing both tree stand and soil C storage.

The major contributors to soil‐surface CO2effluxes are autotrophic and heterotrophic respiration. To evaluate the effect of nutrient additions on the relative contributions from autotrophic and heterotrophic respiration, a large‐scale girdling experiment was performed in a long‐term nutrient optimization experiment in a 40‐year‐old stand of Norway spruce in northern Sweden. Trees on three nonfertilized plots and three fertilized plots were girdled in early summer 2002, and three nonfertilized and three fertilized plots were used as control plots. Each plot was 0.1 ha and contained around 230 trees. Soil‐surface CO2fluxes, soil moisture, and soil temperature were monitored in both girdled and nongirdled plots.

In late July, the time of the seasonal maximum in soil‐surface CO2efflux, the total soil‐CO2efflux in nongirdled plots was 40% lower in the fertilized than in the nonfertilized plots, while the efflux in girdled fertilized and nonfertilized plots was 50% and 60% lower, respectively, than in the corresponding nongirdled controls. We attribute these reductions to losses of the autotrophic component of the total soil‐surface CO2efflux. The estimates of autotrophic respiration are conservative as root starch reserves were depleted more rapidly in roots of girdled than in nongirdled trees. Thus, heterotrophic activity was overestimated.

Calculated on a unit area basis, both the heterotrophic and autotrophic soil respiration was significantly lower in fertilized plots, which is especially noteworthy given that aboveground production was around three times higher in fertilized than in nonfertilized plots.
Sparing land for nature: exploring the potential impact of changes in agricultural yield on the area needed for crop production
Authors: Balmford Andrew , Green Rhys. E. , Scharlemann Jörn P. W.
Published: September 2005

How can rapidly growing food demands be met with least adverse impact on nature? Two very different sorts of suggestions predominate in the literature: wildlife‐friendly farming, whereby on‐farm practices are made as benign to wildlife as possible (at the potential cost of decreasing yields); and land‐sparing, in which farm yields are increased and pressure to convert land for agriculture thereby reduced (at the potential cost of decreasing wildlife populations on farmland). This paper is about one important aspect of the land‐sparing idea – the sensitivity of future requirements for cropland to plausible variation in yield increases, relative to other variables. Focusing on the 23 most energetically important food crops, we use data from the Food and Agriculture Organisation (FAO) and the United Nations Population Division (UNPD) to project plausible values for 2050 for population size, diet, yield, and trade, and then look at their effect on the area needed to meet demand for the 23 crops, for the developing and developed worlds in turn. Our calculations suggest that across developing countries, the area under those crops will need to increase very considerably by 2050 (by 23% under intermediate projections), and that plausible variation in average yield has as much bearing on the extent of that expansion as does variation in population size or per capita consumption; future cropland area varies far less under foreseeable variation in the net import of food from the rest of the world. By contrast, cropland area in developed countries is likely to decrease slightly by 2050 (by 4% under intermediate projections for those 23 crops), and will be less sensitive to variation in population growth, diet, yield, or trade. Other contentious aspects of the land‐sparing idea require further scrutiny, but these results confirm its potential significance and suggest that conservationists should be as concerned about future agricultural yields as they are about population growth and rising per capita consumption.
Effects of afforestation on water yield: a global synthesis with implications for policy
Authors: Farley Kathleen A. , Jobbágy Esteban G. , Jackson Robert B.
Published: September 2005

Carbon sequestration programs, including afforestation and reforestation, are gaining attention globally and will alter many ecosystem processes, including water yield. Some previous analyses have addressed deforestation and water yield, while the effects of afforestation on water yield have been considered for some regions. However, to our knowledge no systematic global analysis of the effects of afforestation on water yield has been undertaken. To assess and predict these effects globally, we analyzed 26 catchment data sets with 504 observations, including annual runoff and low flow. We examined changes in the context of several variables, including original vegetation type, plantation species, plantation age, and mean annual precipitation (MAP). All of these variables should be useful for understanding and modeling the effects of afforestation on water yield. We found that annual runoff was reduced on average by 44% (±3%) and 31% (±2%) when grasslands and shrublands were afforested, respectively. Eucalypts had a larger impact than other tree species in afforested grasslands (P=0.002), reducing runoff (90) by 75% (±10%), compared with a 40% (±3%) average decrease with pines. Runoff losses increased significantly with plantation age for at least 20 years after planting, whether expressed as absolute changes (mm) or as a proportion of predicted runoff (%) (P<0.001). For grasslands, absolute reductions in annual runoff were greatest at wetter sites, but proportional reductions were significantly larger in drier sites (P<0.01 and P<0.001, respectively). Afforestation effects on low flow were similar to those on total annual flow, but proportional reductions were even larger for low flow (P<0.001). These results clearly demonstrate that reductions in runoff can be expected following afforestation of grasslands and shrublands and may be most severe in drier regions. Our results suggest that, in a region where natural runoff is less than 10% of MAP, afforestation should result in a complete loss of runoff; where natural runoff is 30% of precipitation, it will likely be cut by half or more when trees are planted. The possibility that afforestation could cause or intensify water shortages in many locations is a tradeoff that should be explicitly addressed in carbon sequestration programs.
Impact of land use and land cover change on groundwater recharge and quality in the southwestern US
Authors: Scanlon Bridget R. , Reedy Robert C. , Stonestrom David A. , Prudic David E. , Dennehy Kevin F.
Published: September 2005

Humans have exerted large‐scale changes on the terrestrial biosphere, primarily through agriculture; however, the impacts of such changes on the hydrologic cycle are poorly understood. The purpose of this study was to test the hypothesis that the conversion of natural rangeland ecosystems to agricultural ecosystems impacts the subsurface portion of the hydrologic cycle by changing groundwater recharge and flushing salts to underlying aquifers. The hypothesis was examined through point and areal studies investigating the effects of land use/land cover (LU/LC) changes on groundwater recharge and solute transport in the Amargosa Desert (AD) in Nevada and in the High Plains (HP) in Texas, US. Studies use the fact that matric (pore‐water‐pressure) potential and environmental‐tracer profiles in thick unsaturated zones archive past changes in recharging fluxes. Results show that recharge is related to LU/LC as follows: discharge through evapotranspiration (i.e., no recharge; upward fluxes <0.1 mm yr−1) in natural rangeland ecosystems (low matric potentials; high chloride and nitrate concentrations); moderate‐to‐high recharge in irrigated agricultural ecosystems (high matric potentials; low‐to‐moderate chloride and nitrate concentrations) (AD recharge: ∼130–640 mm yr−1); and moderate recharge in nonirrigated (dryland) agricultural ecosystems (high matric potentials; low chloride and nitrate concentrations, and increasing groundwater levels) (HP recharge: ∼9–32 mm yr−1). Replacement of rangeland with agriculture changed flow directions from upward (discharge) to downward (recharge). Recent replacement of rangeland with irrigated ecosystems was documented through downward displacement of chloride and nitrate fronts. Thick unsaturated zones contain a reservoir of salts that are readily mobilized under increased recharge related to LU/LC changes, potentially degrading groundwater quality. Sustainable land use requires quantitative knowledge of the linkages between ecosystem change, recharge, and groundwater quality.
The effect of climate change on the correlation between avian life‐history traits
Authors: Both Christiaan , Visser Marcel E.
Published: September 2005

The ultimate reason why birds should advance their phenology in response to climate change is to match the shifting phenology of underlying levels of the food chain. In a seasonal environment, the timing of food abundance is one of the crucial factors to which birds should adapt their timing of reproduction. They can do this by shifting egg‐laying date (LD), and also by changing other life‐history characters that affect the period between laying of the eggs and hatching of the chicks. In a long‐term study of the migratory Pied Flycatcher, we show that the peak of abundance of nestling food (caterpillars) has advanced during the last two decades, and that the birds advanced their LD. LD strongly correlates with the timing of the caterpillar peak, but in years with an early food peak the birds laid their eggs late relative to this food peak. In such years, the birds advance their hatching date by incubating earlier in the clutch and reducing the interval between laying the last egg to hatching of the first egg, thereby partly compensating for their relative late LD. Paradoxically, they also laid larger clutches in the years with an early food peak, and thereby took more time to lay (i.e. one egg per day). Clutch size therefore declined more strongly with LD in years with an early food peak. This stronger response is adaptive because the fitness of an egg declined more strongly with date in early than in late years. Clearly, avian life‐history traits are correlated and Pied Flycatchers apparently optimize over the whole complex of the traits including LD, clutch size and the onset of incubation. Climate change will lead to changing selection pressures on this complex of traits and presumably the way they are correlated.
Nonlinear response of N2O flux to incremental fertilizer addition in a continuous maize (Zea mays L.) cropping system
Authors: McSwiney Claire P. , Robertson G. Philip
Published: September 2005

The relationship between nitrous oxide (N2O) flux and N availability in agricultural ecosystems is usually assumed to be linear, with the same proportion of nitrogen lost as N2O regardless of input level. We conducted a 3‐year, high‐resolution N fertilizer response study in southwest Michigan USA to test the hypothesis that N2O fluxes increase mainly in response to N additions that exceed crop N needs. We added urea ammonium nitrate or granular urea at nine levels (0–292 kg N ha−1) to four replicate plots of continuous maize. We measured N2O fluxes and available soil N biweekly following fertilization and grain yields at the end of the growing season. From 2001 to 2003 N2O fluxes were moderately low (ca. 20 g N2O‐N ha−1 day−1) at levels of N addition to 101 kg N ha−1, where grain yields were maximized, after which fluxes more than doubled (to >50 g N2O‐N ha−1 day−1). This threshold N2O response to N fertilization suggests that agricultural N2O fluxes could be reduced with no or little yield penalty by reducing N fertilizer inputs to levels that just satisfy crop needs.
Immobilization, stabilization and remobilization of nitrogen in forest soils at elevated CO2: a 15N and 13C tracer study
Authors: Hagedorn Frank , Maurer Stefan , Bucher Jürg B. , Siegwolf Rolf T.W.
Published: September 2005

The fate of immobilized N in soils is one of the great uncertainties in predicting C sequestration at increased CO2 and N deposition. In a dual isotope tracer experiment (13C, 15N) within a 4‐year CO2 enrichment (+200 ppmv) study with forest model ecosystems, we (i) quantified the effects of elevated CO2 on the partitioning of N; (ii) traced immobilized N into physically separated pools of soil organic matter (SOM) with turnover rates known from their 13C signals; and (iii) estimated the remobilization and thus, the bio‐availability of newly sequestered C and N. (1) CO2 enrichment significantly decreased NO3− concentrations in soil waters and export from 1.5 m deep lysimeters by 30–80%. Consequently, elevated CO2 increased the overall retention of N in the model ecosystems. (2) About 60–80% of added 15NH415NO3 were retained in soils. The clay fraction was the greatest sink for the immobilized 15N sequestering 50–60% of the total new soil N. SOM associated with clay contained only 25% of the total new soil C pool and had small C/N ratios (<13), indicating that it consists of humified organic matter with a relatively slow turn over rate. This implies that added 15N was mainly immobilized in stable mineral‐bound SOM pools. (3) Incubation of soils for 1 year showed that the remobilization of newly sequestered N was three to nine times smaller than that of newly sequestered C. Thus, inorganic inputs of N were stabilized more effectively in soils than C. Significantly less newly sequestered N was remobilized from soils previously exposed to elevated CO2. In summary, our results show firstly that a large fraction of inorganic N inputs becomes effectively immobilized in relative stable SOM pools and secondly that elevated CO2 can increase N retention in soils and hence it may tighten N cycling and diminish the risk of nitrate leaching to groundwater.
Pathways of care and resource utilization in a national cohort of patients with transfusion‐acquired hepatitis C
Authors: Brant L. , Harris H. E. , Ramsay M. E. , Grieve R. , Roberts J. ,   on behalf of the HCV National Register Steering Group
Published: September 2005

Summary.  The Hepatitis C Strategy and Action Plan for England recommend that all individuals testing positive for hepatitis C virus (HCV) should be referred to a specialist centre for assessment and care. One key aim is to reduce the number of people progressing to liver disease and therefore reduce the associated costs. The aims of this paper are to describe the care pathways and evaluate resource utilization in a cohort of 826 patients with transfusion‐acquired hepatitis C enrolled in the HCV national register. We reviewed data extracted from patient notes to establish pathways of care since HCV‐positive diagnosis through to May 2002, and to document all treatment, liver biopsy and hospital usage for each patient. Type of care was classified into specialist‐interest in HCV‐related care, other‐hospital care or general practitioner (GP)‐led care. Over 70% of patients were referred to specialist care following HCV diagnosis. Patients who were older or who had normal liver function were less likely to be referred to specialist‐care. Between first diagnosis and May 2002, no patients were referred from GP to specialist‐care. Less than half of this cohort had undergone liver biopsy and only 18% had been treated. Younger patients and those with abnormal liver function were more likely to have undergone liver biopsy and to have received treatment. Analysis of care histories of patients with transfusion‐acquired hepatitis C suggest that changes are needed in the care and management of patients with HCV infection, if the recommendations of the HCV strategy and action plan are to be fully implemented.
Characterization of hepatitis B surface antigen strains circulating in the Kingdom of Cambodia
Authors: Srey C. T. , Ijaz S. , Tedder R. S. , Monchy D.
Published: September 2005

Summary.  A collection of hepatitis B surface antigen (HBsAg)‐reactive serum specimens from the Pasteur Institute of Cambodia was investigated for the genotype, predicted serotype and the presence of diagnostically significant mutations in the surface protein. From a set of 794 samples, 15 were identified serologically to harbour possible HBsAg mutants and were investigated further. An additional 20 samples were included into the study for PCR and sequence analysis. Of the 22 samples which were HBV‐DNA‐positive, 16 were of genotype C with the remaining six being genotype B. Point mutations resulting in amino acid substitutions were noted in 10 samples. The majority of these mutations occurred outside the a determinant.
Exposure to HAV infection in patients with chronic liver disease in Italy, a multicentre study*
Authors: Sagnelli E. , Stroffolini T. , Almasio P. , Mele A. , Coppola N. , Ferrigno L. , Scolastico C. , Onofrio M. , Imparato M. , Filippini P.
Published: September 2005

Summary.  We carried out a multicentre study on 2830 patients with chronic liver disease from 79 liver units (25 in northern, 24 in central and 30 in southern Italy) to evaluate naturally acquired immunity against hepatitis A virus (HAV) in relation to age, sex, geographical area of origin and entity of liver disease, and to define the strategy for specific vaccination. Antibody to HAV (anti‐HAV) was detected in 1514 (53.5%) of the 2830 patients tested; the prevalence was 50.4% in males and 59.1% in females. Both in central and southern Italy the prevalence of anti‐HAV positive subjects increased with increasing age from 43.3 and 44.7%, respectively, in the 0–30‐year‐old subjects to 80.1 and 68.3%, respectively, in those aged over 60 years. The overall prevalence was much lower in northern Italy, as were the variations from one age group to another, from 28.4% in the 0–30‐year‐old subjects to 38% in those aged over 60 years. 40.6% of patients with cirrhosis lacked naturally acquired protection against HAV; this percentage was higher in northern (60.5%) than in central (34.9%, P < 0.0001) and southern Italy (27.6%, P < 0.0001). The high prevalence of patients in Italy with chronic hepatitis or cirrhosis who lack naturally acquired immunity to HAV warrants the implementation of vaccination programmes against hepatitis A in such patients.
Correlation between translation efficiency and outcome of combination therapy in chronic hepatitis C genotype 3
Authors: Yasmeen A. , Hamid S. , Granath F. N. , Lindström H. , Elliott R. M. , Siddiqui A. A. , Persson M. A. A.
Published: September 2005

Summary.  Combination therapy with interferon‐α (IFN‐α) and ribavirin (RBV) in chronic hepatitis C demonstrates the best responses against hepatitis C virus (HCV) of genotype 3. Still, it has proven to be ineffective in 20–30% of patients infected with this genotype. In the present study, we analysed the translation efficiency mediated by the internal ribosome entry site (IRES) region in HCV genotype 3 genomes isolated from sustained responders (SR) and non‐responders (NR), assuming that this may influence the outcome of treatment. Pretreatment isolates of genotype 3 from 22 individuals (15 SR, seven NR) were selected for such analyses. The IRES region [nucleotide (nt) 1–407] was cloned into a dual luciferase vector and IRES activity assessed following transfection into various cell lines. Low relative translation efficiency was observed for IRES elements derived from SR patients, whereas those of NR patients showed significantly greater translation efficiency (29.7 ± 13 vs 69.4 ± 22; P < 0.01). Subsequently, the effect of IFN‐α plus RBV on IRES‐driven translation in vitro was determined. A greater suppressive effect was observed on IRES activity isolated from seven SR patients, when compared with seven NR patients. In conclusion, IRES efficiency in vitro correlated with treatment response for HCV genotype 3. Further studies are warranted to investigate whether IRES efficiency in vitro, or sequence motifs associated with IRES efficiency, will be worthwhile to explore as prognostic tools for other HCV genotypes in the treatment of chronic HCV infection.
Quantitative HBV DNA levels as an early predictor of nonresponse in chronic HBe‐antigen positive hepatitis B patients treated with interferon‐alpha
Authors: Van Der Eijk A. A. , Niesters H. G. M. , Hansen B. E. , Heijtink R. A. , Janssen H. L. A. , Schalm S. W. , De Man R. A.
Published: September 2005

Summary.  To reduce unnecessary exposure to treatment, physicians must decide at an early stage whether continuation of treatment has a reasonable chance of success for the individual patient. The objectives of our study were to evaluate the previously described quantitative hepatitis B e antigen (HBeAg) measurements vs quantitative hepatitis B virus (HBV) DNA measurements for prediction of nonresponse and response in interferon (IFN)‐α treated HBeAg positive chronic HBV patients. Serum HBV DNA and HBeAg levels were assessed at baseline and weeks 8 and 12. For each test (HBV DNA level at baseline, HBV DNA decrease between baseline and weeks 8 and 12, or the combination of these two, as well as HBeAg level at baseline, HBeAg decrease between baseline and weeks 8 and 12, and the combination of these two), we calculated the positive predictive value, negative predictive value, sensitivity and specificity. Monitoring with quantitative HBV DNA levels (area under ROC 0.87) was superior to monitoring with quantitative HBeAg levels (0.76, P < 0.05). Step‐wise logistic regression identified HBV DNA at baseline and decrease in HBV DNA from baseline to week 12, as independent predictors of response. The overall test performance of predicting nonresponse (predictive value 100%) was best for log HBV DNA testing at week 12 compared with testing at week 8 due to a better prediction of sustained response (46%vs 38%) and lower misidentification of nonresponse (39%vs 54%). This study showed that quantitative HBV DNA testing at baseline in combination with a decrease between baseline and week 12 has a high predictive value for identifying patients who have virtually no chance of reaching a sustained response with IFN therapy.
The current pattern of hepatitis B virus infection in Australia
Authors: Tawk H. M. , Vickery K. , Bisset L. , Lo S. K. , Selby W. , Cossart Y. E. ,   the Infection in Endoscopy Study Group
Published: September 2005

Summary.  There is little recent data of the seroprevalence of hepatitis B in Australia. We have surveyed a large cohort of endoscopy patients attending a teaching hospital in central Sydney, and related the presence of hepatitis B virus (HBV) markers with putative risk factors for exposure using the SAS statistical package. Of the 2115 patients tested: 2.1% (45/2115) were HBV surface antigen positive, 0.75% (14/2115) viraemic, 9.5% (200/2115) anti‐HBs and anti‐HBc positive, 20.1% (430/2115) vaccinated (anti‐HBs only) and the remaining 70% were susceptible. The adjusted OR of HBV infection was significantly increased in patients who had been diagnosed with human immunodeficiency virus (36.3‐fold), born in Asia or Pacific islands (12.4‐fold), born in North Africa, Middle East & Mediterranean countries (6‐fold) or born abroad elsewhere in the world (2.7‐fold), had household contact with someone diagnosed with hepatitis between 1980 and 1990 (3.9‐fold), injected drugs between 1980 and 1990 (4.4‐fold), resided in a military establishment for 3 months (2.3‐fold) or in a hospital for 3 months (2.2‐fold), never been vaccinated for hepatitis B (2.8‐fold), received blood transfusion due to an accident and/or a haemorrhage (1.92‐fold) and finally been a male gender (1.59‐fold). The prevalence of HBV in this hospital population was higher than predicted on the basis of notifications to the passive surveillance scheme. Most HBV patients had multiple risk factors for infection, but the hierarchy of odds ratios provides a rational basis for targeted programmes to identify asymptomatic HBV carriers who might benefit from treatment.
Evolutionary genetics and biogeographic structure of Rhizobium gallicum sensu lato, a widely distributed bacterial symbiont of diverse legumes
Authors: SILVA CLAUDIA , VINUESA PABLO , EGUIARTE LUIS E. , SOUZA VALERIA , MARTÍNEZ‐ROMERO ESPERANZA
Published: September 2005

We used phylogenetic and population genetics approaches to evaluate the importance of the evolutionary forces on shaping the genetic structure of Rhizobium gallicum and related species. We analysed 54 strains from several populations distributed in the Northern Hemisphere, using nucleotide sequences of three ‘core’ chromosomal genes (rrs, glnII and atpD) and two ‘auxiliary’ symbiotic genes (nifH and nodB) to elucidate the biogeographic history of the species and symbiotic ecotypes (biovarieties) within species. The analyses revealed that strains classified as Rhizobium mongolense and Rhizobium yanglingense belong to the chromosomal evolutionary lineage of R. gallicum and harbour symbiotic genes corresponding to a new biovar; we propose their reclassification as R. gallicum bv. orientale. The comparison of the chromosomal and symbiotic genes revealed evidence of lateral transfer of symbiotic information within and across species. Genetic differentiation analyses based on the chromosomal protein‐coding genes revealed a biogeographic pattern with three main populations, whereas the 16S rDNA sequences did not resolve that biogeographic pattern. Both the phylogenetic and population genetic analyses showed evidence of recombination at the rrs locus. We discuss our results in the light of the contrasting views of bacterial species expressed by microbial taxonomist and evolutionary biologists.
Variation at two flowering time genes within and among populations of Arabidopsis thaliana: comparison with markers and traits
Authors: CORRE V. LE
Published: September 2005

Flowering Locus C (FLC) and Frigida are two interacting genes controlling flowering time variation in Arabidopsis thaliana. Variation at these genes was surveyed in 12 A. thaliana populations sampled in France. These populations were also screened for variation at molecular markers [12 microsatellites and 19 cleaved amplified polymorphic sequence (CAPS) markers] and at seven quantitative traits measured with and without vernalization. Seven populations were highly polymorphic at markers (HS = 0.57 at microsatellites, 0.24 at CAPS) and showed heritable variation for bolting time and some other traits. Five populations were genetically fixed or nearly fixed. QST for bolting time without vernalization was significantly higher than FST, suggesting local divergent selection. One of the two haplotype groups at FLC (FLCA) was very predominant (frequency of 99%). The first exon of Frigida showed elevated nonsynonymous variation, and nine loss‐of‐function mutations were found throughout the gene. The association between loss‐of‐function and earlier bolting was confirmed. Overall, 18 Frigida haplotypes were detected. The pattern of variation at Frigida was largely similar to that found at markers and traits, with the same populations being fixed or highly diverse. Metapopulation dynamics is thus probably the main factor shaping genetic variation in A. thaliana. However, FST for functional (FRI) vs. nonfunctional (FRIΔ) haplotypes was significantly higher than FST at markers. This suggested that loss‐of‐function at Frigida is under local selection for flowering time.
Historical colonization and demography of the Mediterranean damselfish, Chromis chromis
Authors: DOMINGUES VERA S. , BUCCIARELLI GIUSEPPE , ALMADA VITOR C. , BERNARDI GIACOMO
Published: September 2005

The desiccation of the Mediterranean Sea during the Messinian Salinity Crisis 6.0–5.3 million years ago (Ma), caused a major extinction of the marine ichthyofauna of the Mediterranean. This was followed by an abrupt replenishment of the Mediterranean from the Atlantic after the opening of the Strait of Gibraltar. In this study, we combined demographic and phylogeographic approaches using mitochondrial and nuclear DNA markers to test the alternative hypotheses of where (Atlantic or Mediterranean) and when (before or after the Messinian Salinity Crisis) speciation occurred in the Mediterranean damselfish, Chromis chromis. The closely related geminate transisthmian pair Chromis multilineata and Chromis atrilobata was used as a way of obtaining an internally calibrated molecular clock. We estimated C. chromis speciation timing both by determining the time of divergence between C. chromis and its Atlantic sister species Chromis limbata (0.93–3.26 Ma depending on the molecular marker used, e.g. 1.23–1.39 Ma for the control region), and by determining the time of coalescence for C. chromis based on mitochondrial control region sequences (0.14–0.21 Ma). The time of speciation of C. chromis was always posterior to the replenishment of the Mediterranean basin, after the Messinian Salinity Crisis. Within the Mediterranean, C. chromis population structure and demographic characteristics revealed a genetic break at the Peloponnese, Greece, with directional and eastbound gene flow between western and eastern groups. The eastern group was found to be more recent and with a faster growing population (coalescent time = 0.09–0.13 Ma, growth = 485.3) than the western group (coalescent time = 0.13–0.20 Ma, growth = 325.6). Our data thus suggested a western origin of C. chromis, most likely within the Mediterranean. Low sea water levels during the glacial periods, the hydrographic regime of the Mediterranean and dispersal restriction during the short pelagic larval phase of C. chromis (18–19 days) have probably played an important role in C. chromis historical colonization.
Nitrogen‐fixing nodules from rose wood legume trees (Dalbergia spp.) endemic to Madagascar host seven different genera belonging to α‐ and β‐Proteobacteria
Authors: RASOLOMAMPIANINA R. , BAILLY X. , FETIARISON R. , RABEVOHITRA R. , BÉNA G. , RAMAROSON L. , RAHERIMANDIMBY M. , MOULIN L. , DE LAJUDIE P. , DREYFUS B. , AVARRE J.‐C.
Published: September 2005

Although legume biodiversity is concentrated in tropical regions, the majority of studies on legume nodulating bacteria (LNB) are focused on cultivated leguminous plants from temperate regions. However, recent works on tropical regions tend to indicate that the actual diversity of LNB is largely underestimated. In this study, we report the isolation and characterization of 68 nitrogen‐fixing root nodule bacteria collected from eight endemic tree species of Dalbergia in Madagascar. The isolates were characterized by (i) restriction fragment length polymorphism (RFLP) analysis of 16S‐IGS rDNA, (ii) 16S rDNA gene sequencing and (iii) nodulation tests. Results revealed a wide diversity of bacteria present in the nodules of Dalbergia. Among the 68 isolated bacteria, 65 belonged to Bradyrhizobium, Mesorhizobium, Rhizobium, Azorhizobium and Phyllobacterium from the α‐class of Proteobacteria, and three isolates belonged to Burkholderia and Ralstonia from the β‐class of Proteobacteria. Our results also show for the first time that a strain belonging to the Burkholderia cepacia complex is able to induce efficient nodules on a legume plant.