bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organic matter retention in an upland humic podzol; the effects of pH and solute type
Authors: KENNEDY J. , BILLETT M.F. , DUTHIE D. , FRASER A.R. , HARRISON A.F. 
Published: August 2005

SummaryThis paper discusses the effects of different horizons and soil solution compositions on dissolved organic matter retention in a moorland podzol and compares the results with previous studies of forest podzols. Adsorption isotherms were constructed for each of the major horizons of a freely draining, upland, moorland, humic podzol from north‐east Scotland, to investigate processes of retention and release of dissolved organic matter (DOM). Carbon retention of a range of solute types was studied, and phthalate was chosen as a model compound to measure carbon retention at three different pH values (3, 4.5 and 6). Retention and release of DOM was related to chemical, physical and mineralogical characteristics of the different soil horizons. All the mineral horizons retained DOM, with the Bs horizon most retentive. Solution pH did not significantly affect DOM retention in the O and A horizons. At pH 3 and 4.5 organic matter was weakly retained in the Bhs horizon, but strongly retained in the Bs and the Cx horizons. At pH 6 reversal of surface charge occurred in the Bs and Cx horizons resulting in the release of similar amounts of organic matter to that released from the O horizon at the same pH. The results demonstrate how podzols act as a ‘valve’ in controlling the input of dissolved organic compounds into surface and ground water, and how sensitive the controlling mechanisms are to pH change.
A hard sandy‐loam soil from semi‐arid Northern Cameroon: II. Geochemistry and mineralogy of the bonding agent
Authors: LAMOTTE M. , BRUAND A. , OHNENSTETTER D. , ILDEFONSE P. , PÉDRO G. 
Published: August 2005

SummaryThe hardening of soils containing little clay content has often been related to the cementing of skeleton grains. In sandy‐loam soils from the southern plain of the Chad basin the skeleton grains of the hard horizon are coated and bonded by wall‐shaped bridges. We have studied the bonding agent by X‐ray diffraction on extracted fractions (< 0·5 pm) and by quantitative in situ electron microprobe analysis on thin sections. The coatings and the wall‐shaped bridges are composed mainly of SO2 (mean = 60%), Al2O3 (29%) and FezO3 (7%). The TiO2 and K2O contents were small (1–2%), and the MgO, Na3O and CaO contents were less than 1%. The composition of the coatings and the wall‐shaped bridges is almost homogeneous, even if the Si/Al atomic ratio varies weakly with the morphology of the bridges. The bonding agent constituting the coatings and the wall‐shaped bridges seems to be a mixture of predominantly Al‐Fe beidellite with small contents of kaolinite, illite and quartz. A small content of fine clay minerals plays the major role of bonding agent and is responsible for hardness in sandy or sandy‐loam soils.
La matiére organique soluble à l'eau chaude et la stabilityé de l'agrégation. Aspects méthodologiques et application à des sols ferrallitiques du Congo
Authors: KOUAKOUA E. , SALA G.‐H. , BARTHÈS B. , LARRE‐LARROUY M.‐C. , ALBRECHT A. , FELLER C. 
Published: August 2005

RésuméLa stabilityé de la structure des horizons de surface et de profondeur de sols ferrallitiques du Congo est étudiée en fonction du mode de gestion des terres et de la teneur en carbone organique total des échantillons. Le rôle du carbone soluble à l'eau chaude dans l'agrégation est appréciéà partir de deux approches expérimentales, impliquant des extractions après chauffage en étuve ou en autoclave. Pour ce faire, des comparaisons sont faites entre les taux des macroagrégats stables (>200 pm) à l'eau froide et à l'eau chaude. Les résultats indiquent que les situations culturales étudiées induisent des variations significatives des teneurs en carbone total. Le taux des macroagégats stables à l'eau froide est très fortement corrélé aux teneurs en carbone total et en carbone solubiliséà l'eau chaude. Toutefois, les taux des macroagrégats stables obtenus avant et après extraction du carbone à l'eau chaude ne sont pas significativement différents, ce qui peut remettre en question les résultats sur la fonction agrégeante des matières organiques solubles, déduits des seules approches statistiques.Hot‐water soluble organic matter and aggregate stability. Methodological aspects and application to ferrallitic soils of the CongoSummaryThe structural stability of surface and deeper horizons of ferrallitic soils of the Congo was studied in relation to the land use and the total organic carbon content of the samples. The role of hot‐water soluble carbon in aggregation was assessed with two experimental approaches, one by heating in an oven and the other in an autoclave under pressure. The proportion of aggregates (> 200 μm) stable in cold water were compared with that of macroaggregates stable in hot water. Cropping situation sunder study induced significant variations in total carbon content. Aggregate stability was highly correlated with both soluble and total carbon contents. However, amounts of water‐stable aggregates obtained before and after solubilization of organic matter in hot water were not significantly different. This result would infirm the supposed aggregating role of soluble organic matter, inferred from statistical data only.
Improvement of 13C and 15N CPMAS NMR spectra of bulk soils, particle size fractions and organic material by treatment with 10% hydrofluoric acid
Authors: SCHMIDT M.W.I. , KNICKER H. , HATCHER P.G. , KOGEL‐KNABNER I. 
Published: August 2005

SummaryThe small organic matter content of mineral soils makes it difficult to obtain 13C and 15N nuclear magnetic resonance (NMR) spectra with acceptable signal‐to‐noise ratios. Subjecting such samples to hydrofluoric acid removes mineral matter and leads to a relative increase in organic material. The effect of treatment with 10% hydrofluoric acid on bulk chemical composition and resolution of solid‐state 13C NMR spectra was investigated with six soils, some associated particle size fractions, plant litter and compost. The treatment enhanced the signal‐to‐noise ratio of the solid‐state 13C NMR spectra. The improvement in spectrum quality was greatest in the clay fraction of soil contaminated with coal ash. The removal of paramagnetic compounds associated with the ash may be the main reason for the improvement. Based on total C, total N, C/N ratio and intensity distribution of the solid‐state 13C NMR spectra, no changes in organic matter composition could be detected, except for a possible loss of carbohydrates. After treatment with HF, solid‐state 15N NMR spectra of particle size fractions were obtained and indicated that the observable nitrogen is present mostly as peptides and free amino groups. Extraction with hydrofluoric acid is recommended as a routine treatment prior to solid‐state 13C and 15N NMR on soil containing little C or N and soil samples containing paramagnetic compounds from natural or anthropogenic sources.
Species–area relationships of primates in tropical forest fragments: a global analysis
Authors: HARCOURT A. H. , DOHERTY D. A. 
Published: August 2005

Summary

While in general the tropics and large‐bodied tropical forest mammals are poorly understood, the effects of fragmentation on tropical forest and the tropical mammalian order of primates are relatively well studied. Nevertheless, no quantitative synthesis exists of the response of primates to habitat fragmentation. We therefore conducted a meta‐analysis of the literature on the species–area relationships of primates in forest fragments in order to investigate regularities and differences among continents and sites.
The sample comprised 136 forest fragments (≤ 100 km2) at 33 sites in four continents (Africa, Asia, Madagascar and South America). We conducted our analysis at three spatial scales: global, continent and site. As richness (number of species) per site varied, we analysed both richness and proportional richness by area.
Study sites and size of fragments were unequally distributed across the globe. South America had three times as many sites as any other continent, for which we found less than 10 sites each. Fragment size was small in all continents (global median 1·0 km2).
Despite considerable noise in the data, primate richness and proportional richness generally declined significantly and linearly with fragment area at all spatial scales except in Africa.
Neither isolation (distance of fragment from main forest block) nor age of fragment was an obvious influence on proportional richness. However, the global median isolation was only 2 km.
Synthesis and applications. Fragmentation of habitat clearly threatens the survival of primates. However, study of the effects of fragmentation on primates might be directed in the wrong place. Estimates of minimum area requirements for primate species exceed tens of km2, yet most forest fragments studied measure less than 1 km2. Both to elucidate the biology of contrasts between species in susceptibility to fragmentation and to use research sites for associated conservation efforts, it might be better to direct more attention to fragments of a size in which long‐term persistence of some species is possible.
Long‐term interval burning alters fine root and mycorrhizal dynamics in a ponderosa pine forest
Authors: HART STEPHEN C. , CLASSEN AIMÉE T. , WRIGHT ROBERT J. 
Published: August 2005

SummaryPlant roots and their mycorrhizal symbionts are critical components of forest ecosystems, being largely responsible for soil resource acquisition by plants and the maintenance of soil structure, as well as influencing soil nutrient cycling. Silvicultural treatments should be guided by knowledge of how these below‐ground components respond to different forest management practices.We examined the cumulative effects of 20 years of prescribed burning at 2‐year intervals. We measured fine root length density and fine root and mycorrhizal root biomass in the upper 15 cm of mineral soil in a south‐western ponderosa pine forest over a complete burn cycle.Repeated burning reduced fine root length, fine root biomass and mycorrhizal root biomass, as well as the amount of nitrogen and phosphorus stored in these below‐ground pools.Estimates of fine root production, fine root decomposition and nutrient dynamics were similar in burned and control plots.Synthesis and applications. Although repeated‐prescribed fire may be an effective, low‐cost approach for reducing fuel loads and lessening the chance of a catastrophic wildfire in ponderosa pine forests, our results suggest that this strategy may negatively affect below‐ground biomass pools and nutrient cycling processes in the long term. We recommend that mechanical reductions in fuel loads be conducted in these and similar forests that have not experienced fire for decades, before fire is reintroduced as a management tool.
Gap‐crossing decisions of woodland songbirds in Scotland: an experimental approach
Authors: CREEGAN HELEN P. , OSBORNE PATRICK E. 
Published: August 2005

Summary

Recent declines in woodland birds in Britain have been linked to increasing habitat fragmentation. To understand the effects of fragmentation, data on avian dispersal across woodland gaps are essential but often lacking.
We used song thrush Turdus philomelos mobbing calls to attract songbirds across gaps ranging from 5 to 120 m in width and along comparable woodland edges. Responses were modelled against distance using generalized linear models. Such models have clear applied value for connecting fragmented landscapes.
We also calculated response indices and compared these with bird morphology. The gap‐crossing results were applied to a real landscape in central Scotland and landscape metrics were calculated to judge how perception of habitat connectivity varies interspecifically.
The chaffinch Fringilla coelebs and the robin Erithacus rubecula both responded more readily across gaps than through woodland. There was no difference between gap and edge response for the coal tit Parus ater, while the goldcrest Regulus regulus responded more readily along edges than across gaps. Maximum gap‐crossing distances ranged from 46 m (goldcrest) to 150 m (chaffinch).
There was a positive linear trend between mass of bird and the difference in the maximum response for gap and control experiments. Likewise there was a positive curvilinear relationship between wing area and the difference in probability of response between gap and control experiments at 50 m. These results may be interpreted in terms of manoeuvrability and ability to escape avian predation.
For the central Scotland landscape, the perceived number of patches in the landscape decreased exponentially with increasing gap‐crossing distance, while the median patch size and mean patch fractal dimension increased linearly with gap‐crossing distance.
Synthesis and applications. Our results show that an experimental approach using playback can be used to obtain data on avian gap crossing and the results applied to real landscapes to visualize interspecific differences in habitat perception. This has practical management applications, especially for designing forest habitat networks to maximize avian biodiversity, and potentially could help reverse the recent declines in woodland birds.
Seed inoculation with effective root‐nodule bacteria enhances revegetation success
Authors: THRALL PETER H. , MILLSOM DAVID A. , JEAVONS ALISON C. , WAAYERS MEIGAN , HARVEY GEOFFREY R. , BAGNALL DAVID J. , BROCKWELL JOHN 
Published: August 2005

Summary

Extensive clearing of native vegetation in Australia has contributed to major environmental problems, including land degradation, dryland salinity, soil erosion and loss of biodiversity. Re‐establishing cover with deep‐rooted perennial species is a major focus for conservation and sustainable land management, particularly with regard to hydrological control of recharge and saline discharge areas. However, considerable expense is involved in large‐scale revegetation programmes and cost effectiveness is a real concern.
Low‐cost revegetation approaches are needed that require little maintenance yet can substantially enhance reliable establishment and growth of native trees and shrubs. We evaluated results from direct‐seeding field trials that examined the benefits of using native Australian Acacia species inoculated with effective strains of nitrogen‐fixing root‐nodule bacteria to revegetate degraded landscapes.
On average, inoculation led to a 118% increase in establishment of acacia seedlings, indicating that the use of elite strains of native bacteria can substantially reduce seed requirements. This is a major benefit given the expense of collecting sufficient native seed and the impacts of this activity on remnant population viability.
Particularly at sites experiencing harsher climatic conditions, subsequent survival of inoculated seedlings was significantly greater than for uninoculated controls. Moreover, inoculated acacias grew 10–58% faster than uninoculated controls during the critical early phase of establishment, although this varied among species and sites.
Synthesis and applications. Inoculation of Acacia species or other native leguminous shrubs and trees with elite strains of native rhizobia as part of direct‐seeding techniques has the potential to increase the scope, rate and success of land restoration world‐wide. Re‐establishment of important plant–soil interactions in degraded soils can contribute significantly to the development of biodiverse self‐regenerating native ecosystems in agricultural landscapes.
µ‐Opioid Receptor Preferentially Inhibits Oxytocin Release from Neurohypophysial Terminals by Blocking R‐type Ca2+ Channels
Authors: Ortiz‐Miranda S. , Dayanithi G. , Custer E. , Treistman S. N. , Lemos J. R. 
Published: August 2005

AbstractOxytocin release from neurophypophysial terminals is particularly sensitive to inhibition by the µ‐opioid receptor agonist, DAMGO. Because the R‐type component of the neurophypophysial terminal Ca2+ current (ICa) mediates exclusively oxytocin release, we hypothesised that µ‐opioids could preferentially inhibit oxytocin release by blocking this channel subtype. Whole‐terminal recordings showed that DAMGO and the R‐type selective blocker SNX‐482 inhibit a similar ICa component. Measurements of [Ca2+]i levels and oxytocin release confirmed that the effects of DAMGO and SNX‐482 are not additive. Finally, isolation of the R‐type component and its associated rise in [Ca2+]i and oxytocin release allowed us to demonstrate the selective inhibition by DAMGO of this channel subtype. Thus, µ‐opioid agonists modulate specifically oxytocin release in neurophypophysial terminals by selectively targeting R‐type Ca2+ channels. Modulation of Ca2+ channel subtypes could be a general mechanism for drugs of abuse to regulate the release of specific neurotransmitters at central nervous system synapses.
Leukaemia‐Derived Dendritic Cells Can Be Generated From Blood or Bone Marrow Cells From Patients With Myelodysplasia: A Methodological Approach Under Serum‐Free Culture Conditions
Authors: Kufner S. , Zitzelsberger H. , Kroell T. , Pelka‐Fleischer R. , Salem A. , De Valle F. , Schmid C. , Schweiger C. , Kolb H. J. , Schmetzer H. M. 
Published: August 2005

AbstractFunctional dendritic cells (DC) are professional antigen‐presenting cells (APC) and can be generated in vitro from healthy as well as from leukaemic cells from AML patients giving rise to APC of leukaemic origin presenting leukaemic antigens. In a comparative methodological analysis of 50 AML samples, we could already show that leukaemia‐derived DC can regularly be generated under serum‐free culture conditions. In this study, we describe the generation and characterization of DC from different mononuclear cell (MNC) fractions from 24 myelodysplastic syndrome (MDS) patients under those different serum‐free culture conditions, determine the optimal culture conditions and compare the results with that from 23 healthy donors. In parallel cultures, we compared DC harvests after 7‐ or 14‐day culture, with total or adherent MNC or T‐cell‐depleted MNC or PB or BM–MNC, thawn or fresh MNC, in Xvivo or CellGro serum‐free media, ±10% autologous plasma or ±FL. In detail, we could show that MDS–DC harvests compared to healthy DC were higher after 10‐ to 14‐day culture; total or adherent PB or BM–MNC fractions yield comparable DC counts; however, from MACS‐depleted MNC fractions or thawn MNC lower DC counts can be generated. Whereas the addition of FL increases the DC harvest, the addition of autologous plasma in many cases has inhibitory influence on DC maturation, CellGro and Xvivo media yield comparable DC counts. Optimal harvest of vital and mature DC from MDS samples was obtained with a GM‐CSF, IL‐4, FL and TNF‐α containing serum‐free Xvivo medium after 10–14 days of culture (18/26% DC; 54/64% vital DC; 59/51% mature DC were generated from MDS/healthy MNC samples). Surface marker profiles (e.g. costimulatory antigen expression) of DC obtained from MDS samples were comparable with that of healthy DC. The leukaemic derivation of MDS–DC was demonstrated by the persistence of the clonal cytogenetic aberration in the DC or by coexpression of leukaemic antigens on DC. Autologous T‐cell activation of leukaemia‐derived DC was demonstrated in cases with MDS. Autologous T cells proliferate and upregulate DC‐contact‐relevant antigens. We are the first who demonstrate that the generation of leukaemia‐derived DC is feasible not only in AML but also in MDS under serum‐free culture conditions giving rise to DC with comparable characteristics as healthy DC and offering an antileukaemia‐directed immunotherapeutical vaccination strategy in AML and MDS.
Differential expression of chemokines and chemokine receptors in inflammatory periapical diseases
Authors: Silva T. A. , Garlet G. P. , Lara V. S. , Martins W. , Silva J. S. , Cunha F. Q. 
Published: August 2005

Background:  Periapical lesions are thought to be the result of a local inflammatory response mediated by inflammatory cell infiltration and production of inflammatory mediators. Although chemokines are strongly implicated in the migration and activation of leukocytes in different inflammatory diseases and experimental models, little is known regarding the expression of chemokines and their receptors in human apical periodontitis.Objective and methods:  The objective of this study was to determine the expression of chemokines and their receptors by real‐time polymerase chain reaction in samples obtained from healthy gingiva, periapical granulomas, and inflammatory periradicular cysts. The inflammatory infiltrate was characterized by immunohistochemistry. Results: Comparing cysts and granulomas, an increase in CD4+ and CD8+ cells was observed in granulomas, despite the similar numbers of CD45RO‐positive cells detected in both lesions. The analysis of mRNA expression revealed increased levels of CCR1, CCR2, CCR3, CCR5, CXCR1, and CXCR3 in both types of lesion compared with controls. Cysts exhibited a higher expression of CCR3, CCR5, CXCR1, and CXCR3 compared to granulomas. A significantly higher expression of RANTES, IP‐10, and MCP‐1 was detected in cysts compared with controls or granulomas. The expression of interleukin‐8, MIP‐1α, and MIP‐1β was not different in the three experimental groups.Conclusions:  The increase in Th1 type (CCR1, CCR5, and CXCR3) and Th2 type (CCR2 and CCR3) receptors in both periapical lesions suggests the concomitant occurrence of Th1 and Th2 responses. Furthermore, the prevalent expression of the receptors CCR3, CCR5, CXCR1, and CXCR3 and of the chemokines RANTES, IP‐10, and MCP‐1 in cysts may point to a role in the progression of granulomas to cysts.
From complexity to category: Responding to diagnostic uncertainties of autistic spectrum disorders
Authors: Skellern Catherine , Schluter Philip , McDowell Michael 
Published: August 2005

Objective: Recent data from Education Queensland has identified rising numbers of children receiving diagnoses of autistic spectrum disorder (ASD). Faced with funding diagnostic pressures, in clinical situations that are complex and inherently uncertain, it is possible that specialists err on the side of a positive diagnosis. This study examines the extent to which possible overinclusion of ASD diagnosis may exist in the presence of uncertainty and factors potentially related to this practice in Queensland. Methods: Using anonymous self‐report, all Queensland child psychiatrists and paediatricians who see paediatric patients with development/behavioural problems were surveyed and asked whether they had ever specified an ASD diagnosis in the presence of diagnostic uncertainty. Using logistic regression, elicited responses to the diagnostic uncertainty questions were related to other clinical‐ and practice‐related characteristics. Results: Overall, 58% of surveyed psychiatrists and paediatricians indicated that, in the face of diagnostic uncertainty, they had erred on the side of providing an ASD diagnosis for educational ascertainment and 36% of clinicians had provided an autism diagnosis for Carer's Allowance when Centrelink diagnostic specifications had not been met. Conclusion: In the absence of definitive biological markers, ASD remains a behavioural diagnosis that is often complex and uncertain. In response to systems that demand a categorical diagnostic response, specialists are providing ASD diagnoses, even when uncertain. The motivation for this practice appears to be a clinical risk/benefit analysis of what will achieve the best outcomes for children. It is likely that these practices will continue unless systems change eligibility to funding based on functional impairment rather than medical diagnostic categories.