bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating soil properties in heterogeneous land‐use patches: a Bayesian approach
Authors: Oleson Jacob J. , Hope Diane , Gries Corinna , Kaye Jason 
Published: March 2006

AbstractCities provide unique opportunities for integrating humans into ecology. Using data from a socio‐ecological inventory of metropolitan Phoenix, Arizona, we explore the contribution of human‐related variables to explaining observed variation in soil nitrate‐N (NO3N) and total carbon (C) concentrations across the city, agricultural fields, surrounding desert, and mixed regions. Conventional modeling approaches in such a setting would lead to examination of spatial relationships over the entire study area or on subsets of the data independently. However, the spatial relationships for NO3N and C may be different in each of these regions. Here we estimate the correlation coefficients for influential variables toward soil NO3N and C across the entire region, while at the same time accounting for potentially differing spatial patterns in each of these regions. Soil NO3N shows markedly greater spatial autocorrelation in the desert regions, while the soil C shows varying amounts of spatial relationships in the different regions. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of riparian vegetation on stream bank subaerial processes in southwestern Virginia, USA
Authors: Wynn T. M. , Mostaghimi S. 
Published: March 2006

AbstractRiparian vegetation is frequently used for stream bank stabilization, but the effects of vegetation on subaerial processes have not been quantified. Subaerial processes, such as soil desiccation and freeze–thaw cycling, are climate‐related phenomena that deliver soil directly to the stream and make the banks more vulnerable to fluvial erosion by reducing soil strength. This study compares the impact of woody and herbaceous vegetation on subaerial processes by examining soil temperature and moisture regimes in vegetated stream banks.Soil temperature and water tension were measured at six paired field sites in southwestern Virginia, USA, for one year. Results showed that stream banks with herbaceous vegetation had higher soil temperatures and a greater diurnal temperature range during the summer compared to forested stream banks. Daily average summer soil water tension was 13 to 57 per cent higher under herbaceous vegetation than under woody vegetation, probably due to evapotranspiration from the shallow herbaceous root system on the bank.In contrast to summer conditions, the deciduous forest buffers provided little protection for stream banks during the winter: the forested stream banks experienced diurnal temperature ranges two to three times greater than stream banks under dense herbaceous cover and underwent as many as eight times the number of freeze–thaw cycles. During the winter, the stream banks under the deciduous forests were exposed to solar heating and night time cooling, which increased the diurnal soil temperature range and the occurrence of freeze–thaw cycling.Study results also indicated that freeze–thaw cycling and soil desiccation were greater on the upper stream bank due to thermal and moisture regulation of the lower bank by the stream. Therefore, subaerial erosion and soil weakening may be greater on the upper stream banks. Additional research is needed on the influence of subaerial processes on both subaerial and fluvial erosion. Copyright © 2006 John Wiley & Sons, Ltd.
Grain‐size distribution patterns of a point bar system in the Usri River, India
Authors: Purkait Barendra 
Published: March 2006

AbstractGrain‐size distribution patterns in a point bar system of the Usri River, India, were critically analysed in the light of log‐normal, log‐hyperbolic and log‐skew‐Laplace distribution models. Sand samples were collected from the cross‐bedding foreset of different sizes of bedform; the objectives were to (i) study whether bedform heights have any role in grain‐size distribution patterns, (ii) offer a best‐fit statistical model, (iii) study the downstream variation of size‐sorting in a point bar system, and (iv) study the mechanism of grain sorting.The results indicate that the bedform heights have no role in grain‐size distribution patterns. Quantitatively when the errors in three distribution models were analysed, it was observed that the log‐normal distribution is the best‐fit statistical model and the next one is the log‐skew‐Laplace. However, in the upper reaches of the river, log‐normal distribution is the best‐fit model in the case of large bedforms, whereas in the lower reaches the log‐normal model is the best‐fit one in the case of small bed forms.It is also observed that within a point bar, for large and small bedforms, there is a tendency for mean grain size to decrease downstream. Between point bars for large bedforms there is no consistency in decreasing grain size downstream, whereas for small bed forms the decrease of grain size downstream is observed except near the confluence at Palkia.With distance of transport, the coarser and finer fractions of sediments are gradually chopped off. The coarser fractions are buried below the advancing bedforms on the lee sides and the finer ones are transported further downstream. Thus the finer admixture giving rise to the fining‐upward sequence overlies a carpet of coarser materials. This mechanism provides a clue to the process of grain sorting in the fluvial environment.An interpretation has been offered for the log‐normality of the grain‐size distribution pattern. During prolonged transportation in a fluvial environment, the larger grain‐size fractions are gradually chopped off and buried below the advancing bedforms on their lee sides. On the other hand, the finer fractions are transported further downstream in suspension. Thus the narrow, intermediate size fraction takes active part in the distribution patterns leading to the generation of unimodality and a symmetric distribution pattern downstream, which are the main criteria for log‐normality. Similarly, increase of bedform size is the effect of increase of stream power and Froude number leading to the selective segregation of bed materials. Thus the intermediate size fractions take a more active part than the coarser and the finer size fractions in developing log‐normality.Besides the hydrodynamic parameters of the Usri, coarsening of grain size downstream has been attributed to (i) the aggrading nature of the Usri downstream, and (ii) the contribution of coarser materials to the Usri by its tributaries and bank erosion. Copyright © 2006 John Wiley & Sons, Ltd.
Soil detachment and transport on field‐ and laboratory‐scale interrill areas: erosion processes and the size‐selectivity of eroded sediment
Authors: Issa O. Malam , Bissonnais Y. Le , Planchon O. , Favis‐Mortlock David , Silvera Norbert , Wainwright John 
Published: March 2006

AbstractField‐ and laboratory‐scale rainfall simulation experiments were carried out in an investigation of the temporal variability of erosion processes on interrill areas, and the effects of such variation upon sediment size characteristics. Poorly aggregated sandy soils from the semi‐arid environment of Senegal, West Africa, were used on both a 40 m2 field plot and a 0·25 m2 laboratory plot; rainfall intensity for all experiments was 70 mm h−1 with a duration of 1 to 2 hours. Time‐series measurements were made of the quantity and the size distribution of eroded material: these permitted an estimate of the changing temporal balance between the main erosion processes (splash and wash). Results from both spatial scales showed a similar temporal pattern of runoff generation and sediment concentration. For both spatial scales, the dominant erosional process was detachment by raindrops; this resulted in a dynamic evolution of the soil surface under raindrop impact, with the rapid formation of a sieving crust followed by an erosion crust. However, a clear difference was observed between the two scales regarding the size of particles detached by both splash and wash. While all measured values were lower than the mean weight diameter (MWD) value of the original soil (mean 0·32 mm), demonstrating the size‐selective nature of wash and splash processes, the MWD values of washed and splashed particles at the field scale ranged from 0·08 to 0·16 mm and from 0·12 to 0·30 mm respectively, whereas the MWD values of washed and splashed particles at the laboratory scale ranged from 0·13 to 0·29 mm and from 0·21 to 0·32 mm respectively. Thus only at the field scale were the soil particles detached by splash notably coarser than those transported by wash. This suggests a transport‐limited erosion process at the field scale. Differences were also observed between the dynamics of the soil loss by wash at the two scales, since results showed wider scatter in the field compared to the laboratory experiments. This scatter is probably related to the change in soil surface characteristics due to the size‐selectivity of the erosion processes at this spatial scale. Copyright © 2006 John Wiley & Sons, Ltd.
Viscous flow computations of aircraft with changing control surface deflection using unstructured dynamic meshes
Authors: Murayama Mitsuhiro , Ito Yasushi , Nakahashi Kazuhiro , Matsushima Kisa , Iwamiya Toshiyuki 
Published: March 2006

AbstractA three‐dimensional unstructured dynamic mesh method for viscous flow computations is presented to simulate aircraft performance when control surface deflection is changed. The method includes an efficient surface mesh movement algorithm for unstructured hybrid meshes comprised of tetrahedra, prisms and pyramids. The method is applied to numerical simulations of the static longitudinal stability control of an experimental supersonic airplane designed at the Japan Aerospace Exploration Agency (previously known as the National Aerospace Laboratory of Japan). The deflection angles of the horizontal tail wings are changed at freestream Mach numbers of 2.0 and 0.95. The results are validated by comparison with experimental results, and the differences in the flow characteristics at the given flow conditions are estimated. Copyright © 2006 John Wiley & Sons, Ltd.
Evolution of novelty in the cichlid dentition
Authors: Streelman Jeffrey Todd , Albertson R. Craig 
Published: March 2006

AbstractThe shape of teeth occupies a central position in various biological disciplines, from paleo‐ecology to molecular biology to cosmetic and reconstructive dentistry. Despite a long tradition of study in mammals, important questions remain regarding the genetic and developmental basis of differences in tooth shape. Here, we use natural mutants of cichlid fish from East Africa, which exhibit tremendous dental diversity, to help fill the gaps in our understanding of vertebrate odontogenesis. We employ an expanded genetic linkage map to demonstrate that cusp number segregates as a gene of major effect, which explains ∼40% of the phenotypic variance, on cichlid chromosome 5. Furthermore, we examine patterns of Bmp4 expression in early odontogenesis to address and refine predictions of models linking tooth shape and tooth number. Mutations in the Bmp4 cistron do not control tooth shape in this mapping cross. Our data suggest that the evolution of novelty in the cichlid dentition is galvanized by a small number of genetic changes, echoing similar conclusions from recent studies of other vertebrate adaptive morphologies. J. Exp. Zool. (Mol. Dev. Evol.) 306B, 2006. © 2006 Wiley‐Liss, Inc.
Accurate quantification of visceral adipose tissue (VAT) using water‐saturation MRI and computer segmentation: Preliminary results
Authors: Armao Diane , Guyon Jean‐Philippe , Firat Zeynep , Brown Mark A. , Semelka Richard C. 
Published: March 2006

AbstractPurposeTo describe and evaluate the accuracy of water‐saturation MRI and a computer segmentation program for quantification of visceral adipose tissue (VAT).Materials and MethodsMRI was performed on five patients with whole‐volume coverage of the abdomen using two different sequences: 1) a T1‐weighted spoiled gradient‐echo breath‐hold sequence (non‐water‐saturation) and 2) a T1‐weighted spoiled gradient‐echo water‐saturation breath‐hold sequence (water‐saturation). The computer segmentation program analyzed the data and calculated VAT volumes (cm3) from both sequences. The data from one patient were additionally processed with the use of a manual technique. The intrastudy reproducibility of the proposed method using the water‐saturation MRI sequence and the computer segmentation technique was tested by repeated measures of the automated system analysis (×10) on MRI data from a single subject to calculate variability.ResultsVAT volumes measured by the water‐saturation MRI sequences were consistently greater than those measured by the non‐water‐saturation sequences. Comparison of VAT volumes derived from the water‐saturation images and measured by the computer segmentation technique vs. the manual technique showed good correlation (K = 0.8), with a significant time‐saving benefit associated with the automated method (5 minutes vs. 1 hour). There was poor correlation between VAT volume measurement calculated by the manual technique and the computer segmentation technique using non‐water‐saturation images. The reproducibility of the computer segmentation technique using data derived from water‐saturation images was high, with a low variability (±5%).ConclusionThe results obtained demonstrate that the proposed method may be able to provide accurate quantification of VAT in a highly reproducible and efficient manner. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Diffusion tensor imaging (DTI) of rodent brains in vivo using a 1.5T clinical MR scanner
Authors: Lee Francis K.H. , Fang Ma‐Rong , Antonio Gregory E. , Yeung David K.W. , Chan Edward T.Y. , Zhang Li‐Hong , Yew David T. , Ahuja Anil T. 
Published: March 2006

AbstractPurposeTo evaluate the feasibility of using a clinical 1.5T MR scanner to perform magnetic resonance (MR) diffusion tensor imaging (DTI) on in vivo rodent brains and to trace major rodent neuronal bundles with anatomical correlation.Materials and MethodsTwo normal adult Sprague Dawley (SD) rats were anesthetized and imaged in a 1.5T MR scanner with a microscopic coil. DTI was performed at a resolution of 0.94 mm × 0.94 mm × 0.5 mm (reconstructed to 0.47 mm × 0.47 mm × 0.5 mm, with b‐factors of 600 seconds/mm2 and 1000 seconds/mm2) and a higher resolution of 0.63 mm × 0.63 mm × 0.5 mm (reconstructed to 0.235 mm × 0.235 mm × 0.5 mm, with a b‐factor of 1500 seconds/mm2). The fiber‐tracking results were correlated with corresponding anatomical sections stained to visualize neuronal fibers. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the neuronal fibers were measured and compared with results in published reports.ResultsSeveral major neuronal fiber tracts, including the corticospinal cord, corpus callosum, and anterior commissure, were identified in all DTI data sets. Stained anatomical sections obtained from the rats confirmed the location of these fibers. The ADC values (0.6–0.8 ± 10−3 mm2/second) of the fibers were similar to published figures. However, the FA values (0.3–0.35) were lower than those obtained in previous studies of white matter in rodent spinal cord.ConclusionWe have demonstrated the feasibility of using a 1.5T clinical MR scanner for neuronal fiber tracking in rodent brains. The technique will be useful in rodent neuroanatomy studies. Further investigation is encouraged to verify the FA values generated by DTI with such techniques. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Pathological effects of glyoxalase I inhibition in SH‐SY5Y neuroblastoma cells
Authors: Kuhla Björn , Lüth Hans‐Joachim , Haferburg Dietrich , Weick Michael , Reichenbach Andreas , Arendt Thomas , Münch Gerald 
Published: March 2006

AbstractIn Alzheimer's disease (AD), in aging, and under conditions of oxidative stress, the levels of reactive carbonyl compounds continuously increase. Accumulating carbonyl levels might be caused by an impaired enzymatic detoxification system. The major dicarbonyl detoxifying system is the glyoxalase system, which removes methylglyoxal in order to minimize cellular impairment. Although a reduced activity of glyoxalase I was evident in aging brains, it is not known how raising the intracellular methylglyoxal level influences neuronal function and the phosphorylation pattern of tau protein, which is known to be abnormally hyperphosphorylated in AD. To simulate a reduced glyoxalase I activity, we applied an inhibitor of glyoxalase I, p‐bromobenzylglutathione cyclopentyl diester (pBrBzGSCp2), to SH‐SY5Y neuroblastoma cells to induce chronically elevated methylglyoxal concentrations. We have shown that 10 μM pBrBzGSCp2 leads to a fourfold elevation of the methylglyoxal level after 24 hr. In addition, glyoxalase I inhibition leads to reduced cell viability, strongly retracted neuritis, increase in [Ca2+]i, and activation of caspase‐3. However, pBrBzGSCp2 did not lead to tau “hyper”‐phosphorylation despite activation of p38 mitogen‐activated protein kinase and c‐Jun NH2‐terminal kinase but rather activated protein phosphatases 2 and induced tau dephosphorylation at the Ser202/Thr205 and Ser396/Ser404 epitopes. Preincubation with the carbonyl scavenger aminoguanidine prevented tau dephosphorylation, indicating the specific effect of methylglyoxal. Also, pretreatment with the inhibitor okadaic acid prevented tau dephosphorylation, indicating that methylglyoxal activates PP‐2A. In summary, our data suggest that a reduced glyoxalase I activity mimics some changes associated with neurodegeneration, such as neurite retraction and apoptotic cell death. © 2006 Wiley‐Liss, Inc.
Enhanced endocrine response to novel environment stress and lack of corticosterone circadian rhythm in staggerer (Rora sg/sg) mutant mice
Authors: Frédéric Florence , Chianale Colette , Oliver Charles , Mariani Jean 
Published: March 2006

AbstractThe staggerer (Rora sg/sg) mutation is a deletion in the retinoid‐related orphan receptor (RORα) gene that prevents translation of the ligand‐binding domain (LBD), leading to the loss of RORα activity. RORα is a transcription factor that belongs to the nuclear receptor superfamily. In the brain, RORα is expressed in specific areas, including the cerebellum and suprachiasmatic nucleus (SCN). The homozygous Rora sg/sg mutant mouse, of which the most obvious phenotype is ataxia associated with cerebellar degeneration, also overproduces inflammatory cytokines. Here we compared the response to novelty stress of staggerer and wild‐type mice as well as their diurnal cycles of adrenocorticotropic hormone and corticosterone secretion. We show that the staggerer mouse displays an enhanced endocrine response to novelty stress, which is not due to the enhanced production of interleukin‐1 (IL‐1), insofar as it is not blocked by pretreatment with IL‐1ra and lacks the diurnal shift in corticosterone nonstressed levels; this last feature might be related to the expression of RORα in the SCN, a structure that maintains the circadian clock and plays a role in timing rhythmic physiology and behavior. © 2006 Wiley‐Liss, Inc.
Developmental changes in Ca2+‐regulated functions of early postnatal Purkinje neurons
Authors: Gruol D.L. , Quina L.A. , Netzeband J.G. , Nguyen D. , Gullette C.E. 
Published: March 2006

AbstractCa2+ influx through L‐type Ca2+ channels regulates several different cellular processes in developing Purkinje neurons, including activation of transcription factors and expression of cellular proteins. In the current studies, we examined the age dependence of these actions of Ca2+ during the early developmental period. Purkinje neurons acutely isolated from postnatal day 4–8 rat pups were studied. We also examined the sensitivity of the Ca2+‐regulated processes to a toxic environmental factor (ethanol) known to show age‐dependent actions on developing Purkinje neurons. Results show that Ca2+ activation of the transcription factor cAMP‐responsive element binding protein (CREB) and Ca2+‐induced alterations in the level of the apoptotic enzyme caspase 3 show both dose and age dependence in the early‐developing Purkinje neurons. Interestingly, the age dependence was opposite for the two proteins. Ca2+ regulation of calbindin, a Ca2+ binding protein, was dose dependent but showed little age dependence. Exposure to ethanol altered Ca2+ activation of pCREB in an age‐dependent manner but did not alter Ca2+ regulation of caspase 3 or calbindin levels. Taken together, these results show that the downstream effects of Ca2+ signaling have age‐dependent components during early Purkinje neuron development. This age dependence may play an important role in the normal developmental program and could contribute to the critical window of sensitivity observed for certain toxic agents during early development. © 2006 Wiley‐Liss, Inc.
Local land use strategies in a globalizing world—managing social and environmental dynamics
Authors: Wadley R. L. , Mertz O. , Christensen A. E. 
Published: March 2006

AbstractThis special issue deals with local rural people's economic, social and cultural responses to external and internal pressures generated by processes of global and regional change. The contributions deal with issues of resource‐base degradation and stable land management, with special emphases on market integration and increased vulnerability of natural resources and local livelihoods in Lao DPR; land‐use change in a Malaysian swidden system under varied patterns of migration and off‐farm labour; occupational multiplicity and agricultural specialization in the Philippines; land degradation and environmental perceptions in peri‐urban Nigeria; food security, gendered labour and shifting cultural‐economic values in Uganda; and the rehabilitation of environment and social institutions through neo‐localism in Thailand. All of the articles were originally presented at an International Conference in Copenhagen, Denmark in 2003, under the auspices of the Danish University Consortium on Environment and Development—Sustainable Land Use and Natural Resource Management (DUCED SLUSE). Copyright © 2006 John Wiley & Sons, Ltd.
Forests, marketization, livelihoods and the poor in the Lao PDR
Authors: Rigg J. D. 
Published: March 2006

AbstractThe Lao PDR is making the transition from subsistence to cash, and command to market. Rural communities are being drawn ever more tightly into the embrace of the market economy and of the central state. The construction of roads, schools and health centres, the provision of credit and new crops and technologies, and the arrival of traders and the panoply of the consumer economy are all, in their different ways, remoulding rural economy and society. This paper looks at one aspect of this multi‐stranded process of agrarian transformation: the role and place of forests and, in particular, non‐timber forest products, in rural people's lives and livelihoods. The paper highlights the contradictory and uneven livelihood‐eroding/enhancing effects of these transformations. In many upland areas of Laos livelihoods are being squeezed from ‘below’ by environmental degradation and from ‘above’ by the operation of government policies and, more generally, by evolving market relations. While market pessimists see market integration as a largely destructive process, the paper highlights the opportunities that market integration can provide through diversification and livelihood reorientation. The challenge is that these opportunities are unequally available and are likely to promote social differentiation. Some households find themselves in a position to embrace new opportunities while others are forced to continue to rely on a declining and degrading forest resource. Copyright © 2006 John Wiley & Sons, Ltd.