bluuebunny/crossref_metadata_2025 huggingface dataset:
2,3,6,7,10,11‐Hexamethoxytribenzotriquinacene: Synthesis, Solid‐State Structure, and Functionalization of a Rigid Analogue of Cyclotriveratrylene
Authors: Harig Marco , Neumann Beate , Stammler Hans‐Georg , Kuck Dietmar
Published: May 2004

The syntheses of several tribenzotriquinacenes bearing six methoxy groups at the outer peripheral positions of the aromatic rings are reported. The centro‐methyl derivative is accessible in surprisingly good yield through two‐fold cyclodehydration in the final step of a synthesis route which requires special care in the preparation of some electron‐rich key intermediates, such as 5,6‐dimethoxy‐2‐methylindane‐1,3‐dione and bis(3,4‐dimethoxyphenyl)methanol. X‐ray single‐crystal structure analysis of the centro‐methyl derivative confirms its C3v‐symmetrical molecular structure but, at variance from the parent centro‐methyltribenzotriquinacene and the similarly shaped cyclotriveratrylene, the hexamethoxytribenzotriquinacene analog does not form columnar stacks in the solid state. Functionalization of the three benzhydrylic bridgehead positions leads to the tetramethyl analog and the bridgehead triol in good yields. In contrast, attempts to functionalize the ortho positions by nitration or bromination mainly give rise to ring cleavage through electrophilic ipso attack, which parallels the behavior of cyclotribenzylenes and cyclotriveratrylenes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The Conformation of Alkyl Benzyl Alcohols Studied by ab initio MO Calculations − A Comparison with IR and NMR Spectroscopic Data
Authors: Takahashi Osamu , Saito Ko , Kohno Yuji , Suezawa Hiroko , Ishihara Shinji , Nishio Motohiro
Published: May 2004

Ab initio MO calculations were carried out for the conformations of a series of alkyl‐substituted benzyl alcohols C6H5CH2CHOH−R (R = CH3, C2H5, iPr, tBu) at the MP2/6‐311G(d,p)//MP2/6‐31G(d) level. It was found that the conformation where the OH group is gauche to the phenyl group is the most stable. The geometry where both the OH and R groups are close to phenyl is the second most stable. This finding has been interpreted on the grounds of the attractive OH/π and CH/π hydrogen bonds and a repulsive van der Waals interaction between vicinal CH groups. NMR nuclear Overhauser effects, spin‐coupling data, and IR spectroscopic data are consistent with the conclusion given by the MO calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis of 3′−3′‐Linked Pyrimidine Oligonucleotides Containing an Acridine Moiety for Alternate Strand Triple Helix Formation
Authors: Amato Jussara , Galeone Aldo , Oliviero Giorgia , Mayol Luciano , Piccialli Gennaro , Varra Michela
Published: May 2004

Oligonucleotides with a 3′−3′ inversion of polarity, containing an acridine moiety attached to the nucleotide base flanking the 3′−3′ phosphodiester bond, have been synthesised, characterised and used to form alternate‐strand triple helix complexes. These have been investigated by UV melting studies and CD experiments. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A Radical Roundabout for an Unprecedented Tandem Reaction Including a Homolytic Substitution with a Titanium‐Oxygen Bond
Authors: Gansäuer Andreas , Rinker Björn , Ndene‐Schiffer Noëllie , Pierobon Marianna , Grimme Stefan , Gerenkamp Mareike , Mück‐Lichtenfeld Christian
Published: May 2004

Conceptually novel homolytic substitutions (SH2) of ClCp2Ti−O bonds with benzylic, secondary and tertiary alkyl radicals are described. The intermediates and crucial transition structures were studied by DFT methods. The resulting atom economical radical tandem reaction can be utilized for the synthesis of structurally complex tetrahydrofurans from simple starting materials and is therefore of interest for natural product synthesis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
2,6‐Bis(pyrazolyl)pyridine Functionalised with Two Nitronylnitroxide and Iminonitroxide Radicals
Authors: Zoppellaro Giorgio , Geies Ahmed , Enkelmann Volker , Baumgarten Martin
Published: May 2004

During the last two decades, growing interest in the field of material chemistry has been focused on the synthetic design of organic high‐spin molecules for use as novel magnetic materials. Conjugated radicals based on the bis(pyrazolyl)pyridine core are very attractive in principle, since they per se combine optical, chelating and magnetic properties on a single molecular entity. The functionalisation of this core via the bis(4′‐formyl) derivatives with Ullman radicals results in novel functional biradicals, which may further be used for supramolecular architectures. In this paper we describe the synthesis, structure and properties of 2,6‐bis[4′‐(3‐oxo‐1‐oxyl‐4,4,5,5‐tetramethylimidazolin‐2‐yl)pyrazol‐1′‐yl]pyridine (Pz2PyNN) and 2,6‐bis[4‐(1‐oxyl‐4,4,5,5‐tetramethylimidazolin‐2‐yl)pyrazolyl]pyridine (Pz2PyIN). The two biradicals can clearly be differentiated by UV/Vis, IR and EPR spectroscopy. The optical absorptions of the blue Pz2PyNN appear around λmax= 610 nm (ϵ ≈︁ 1700 M−1 cm−1) while for Pz2PyIN the orange‐red colour arises from absorptions at λmax= 468 nm (ϵ ≈︁ 1400 M−1 cm−1). A triplet ground state for the bis(nitronylnitroxide) Pz2PyNN with ΔES‐T ≈︁ 11.8 ± 4.8 cm−1 can be deduced from the EPR studies because of the increase of the double integrated intensity times temperature at very low temperatures, indicating complete population of the triplet state. For the related bis(iminonitroxide) Pz2PyIN a much smaller (at least one order of magnitude lower) singlet−triplet energy gap with an upper limit of 0.7 cm−1 has been derived (0.7 ⪖ ΔES‐T ⪖ −0.07 cm−1). The new multifunctional biradicals represent the first example of high‐spin molecules in the bis(pyrazolyl)pyridine family. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Toward Diels−Alder Reactions on a Solid Support Using Polymer Bound N‐Substituted 3‐Hydroxy‐4,4‐dimethyl‐2‐pyrrolidinone Acrylate Derivatives
Authors: Akkari Rhalid , Calmès Monique , Martinez Jean
Published: May 2004

Several N‐substituted 3‐hydroxy‐4,4‐dimethyl‐2‐pyrrolidinone acrylate derivatives, selected to allow their attachment to a polymer, have been prepared and tested as dienophiles in the Diels−Alder reaction. The experiments, performed under TiCl4 catalysis in solution or the solid phase with isoprene and cyclopentadiene as dienes, pointed out the difficulties associated with some of these compounds that failed to give the corresponding cycloadduct. 13C NMR studies provided some evidence regarding the nature of the interactions between the acrylate compounds and TiCl4. It appears that the outcome of the reaction is dependent on the acrylate structure and that the 4‐(3‐hydroxy‐4,4‐dimethyl‐2‐oxopyrrolidin‐1‐yl)benzoic acid acrylate derivatives are highly efficient to give the cycloadduct in good yield and with high regio‐ or endoselectivity in both solution and solid‐phase reaction conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Interaction of Dihydropyridines and Nucleophiles with Carbene Complexes of Chromium: Diastereo‐ and Enantioselective Synthesis of Polycyclic Butenolides
Authors: Rudler Henri , Parlier Andrée , Certal Victor , Lastennet Gabriel , Audouin Max , Vaissermann Jacqueline
Published: May 2004

The interaction ofN‐methyldihydropyridine with carbene complexes of chromium promotes their spontaneous homologation upon addition of a hydride to the carbene carbon and an insertion of CO. This is followed in the case of complexes tethered to a triple bond by cascade insertions of the triple bond and of a CO ligand giving finally butenolides. The scope of the reaction has been established with its limitations, together with the stereochemical outcome, which is discussed. [5.5], [5.6], [5.7] bicyclic and tricyclic systems have been synthesised together with chiral butenolides starting from chiral carbene complexes. Most of the new structures have been assessed by X‐ray crystallography. This transformation was first extended to dihydronicotinamides, to chiral dihydropyridines such as dihydronicotines which led to the butenolides in an enantioselective way, and to other sources of hydrides. Second, a series of nucleophiles such as alkoxides, alkyllithium and alkylmagnesium compounds led also to polycyclic, substituted butenolides. Moreover, the final lactone enolates could be trapped with oxygen and gave unsaturated lactonols. The key point in all of these reactions is the formation of tetrahedral intermediates upon interaction of the nucleophiles with the carbene carbon. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
2‐Oxopiperazine Scaffolds by [3+2] Cycloaddition Reactions with a Polymer‐Supported Cyclic Nitrone
Authors: Wierschem Frank , Rück‐Braun Karola
Published: May 2004

Isoxazolidines and 1,3‐aminoalcohols with a piperazin‐2‐one skeleton were readily prepared on a solid support through [3+2] cycloaddition and subsequent N−O‐bond cleavage, starting from a polymer‐supported cyclic nitrone. Libraries of functionalized 1,3‐aminoalcohols and their derivatives were obtained by automated amine acylation and Mitsunobu reactions on a solid support. The key to success is the oxidation of the immobilized cyclic secondary amine precursor to the nitrone on a solid support and the reductive N−O‐bond cleavage of the isoxazolidines, employing Mo(CO)6. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
“Aha!” effects in a guessing riddle task: An event‐related potential study
Authors: Mai Xiao‐Qin , Luo Jing , Wu Jian‐Hui , Luo Yue‐Jia
Published: May 2004

Insight problem solving has been the topic of much investigation. It is believed widely that insight critically contains the process of breaking one's mental set. Recent functional magnetic resonance imaging (fMRI) research on puzzle solving showed that insight was associated with activities in anterior cingulate cortex (ACC) and other areas (Luo and Niki [2003]: Hippocampus 13:274–281). We proposed ACC might mediate processes of breaking one's mental set, given its well‐known role in cognitive conflict. In the present research, high‐density event‐related potentials (ERPs) were recorded to examine the electrophysiologic correlates of insight problem solving. One hundred twenty interesting Chinese riddles (half difficult and half easy) were adopted as materials. For each trial, subjects were either given an easy puzzle followed by a keyword that was consistent with the subject's initial thinking (“No‐aha answer”), or a difficult puzzle followed by a keyword that was consistent with an unusual interpretation, so that it broke the subject's initial mental set (“Aha answer”). Results from 14 subjects showed that Aha answers elicited a more negative ERP deflection than did No‐aha answers in the time window from 250–500 msec after onset of the answer. The ERP difference wave (Aha minus No‐aha answer) showed the maximum amplitude over the central site (Cz) with a peak latency of 380 msec (N380). Voltage and current density maps of the difference wave showed strong activity and current density in the frontocentral region. Dipole analysis localized the generator of the N380 in the ACC. N380 therefore probably reflects an “Aha!” effect, and the ACC generator may be involved in the breaking of mental set. Hum. Brain Mapp. 22:261–270, 2004. © 2004 Wiley‐Liss, Inc.
Cross‐modal temporal order memory for auditory digits and visual locations: An fMRI study
Authors: Zhang Daren , Zhang Xiaochu , Sun Xiwen , Li Zhihao , Wang Zhaoxin , He Sheng , Hu Xiaoping
Published: May 2004

A function of working memory is to remember the temporal sequence of events, often occurring across different sensory modalities. To study the neural correlates of this function, we conducted an event‐related functional magnetic resonance imaging (fMRI) experiment with a cross‐modal memory task. Subjects were required to recall auditory digits and visual locations either in mixed order (cross‐modality) or in separate order (within‐modality). To identify the brain regions involved in the memory of cross‐modal temporal order, we compared the blood oxygenation level‐dependent (BOLD) response between the mixed and the separate order tasks. As a control, cortical areas sensitive to the memory load were mapped by comparing the 10‐item condition with the 6‐item condition in the separate order task. Results show that the bilateral prefrontal, right premotor, temporo‐parietal junction (TPJ) and left superior parietal cortices had significantly more activation in the mixed task than in the separate task. Some of these areas were also sensitive to the memory load, whereas the right prefrontal cortex and TPJ were relatively more sensitive to the cross‐modal order but not the memory load. Our study provides potential neural correlates for the episodic buffer, a key component of working memory as proposed previously [Baddeley. Trends Cogn Sci 2000;4:417–423]. Hum. Brain Mapping 22:280–289, 2004. © 2004 Wiley‐Liss, Inc.
Lingual abscess: diagnosis and treatment
Authors: Balatsouras Dimitrios G. , Eliopoulos Panayotis N. , Kaberos Antonis C.
Published: May 2004

Background.

Lingual abscesses are very rare, and as a result, the individual surgeon usually lacks experience in the diagnosis and therapy of this entity. We present four cases of abscesses of the tongue diagnosed and treated during the past 2 years.

Methods.

The medical records, films, and charts of four patients with lingual abscess were retrospectively reviewed. The clinical presentation, radiographic features, treatment, and outcome of the cases were examined.

Results.

Diagnosis was obtained by clinical examination and CT. In all cases, we avoided incision and drainage and preferred draining the abscess and aspirating pus with a large‐bore needle through the inferior surface of the tongue. All patients responded remarkably well and did not have any recurrence.

Conclusions.

Lingual abscesses are rare conditions. In contrast to the approach in cases of most deep neck space infections, a more conservative therapeutic approach by needle‐aspiration is effective and has the advantages of not exacerbating the edema of the tongue and of avoiding airway compromise. © 2004 Wiley Periodicals, Inc. Head Neck 26: 550–554, 2004
Pediatric submandibular triangle masses: a fifteen‐year experience
Authors: Hockstein Neil G. , Samadi Daniel S. , Gendron Kristin , Carpentieri David , Wetmore Ralph F.
Published: May 2004

Background.

The purpose of this study was to evaluate the surgical results of pediatric submandibular triangle masses, with specific attention to neoplastic processes.

Methods.

We retrospectively reviewed the medical records of 105 patients aged 6 months to 21 years who underwent surgery in the submandibular triangle at a major pediatric tertiary care hospital from 1987 to 2001.

Results.

One hundred five patients who underwent surgery in the submandibular triangle were included in the study. Twenty patients had neoplastic processes, six of which were of primary salivary origin (two mucoepidermoid carcinomas and four pleomorphic adenomas). Twenty‐four patients underwent excision of inflamed or infected lymph nodes, and 23 patients underwent excision of inflamed or infected submandibular glands. Thirty‐eight patients were included who underwent surgery for sialorrhea or to gain access for another surgical procedure. Complications included tumor recurrence, transient and permanent marginal mandibular nerve weakness, ranula, postoperative fluid collection, and cellulitis. Duration of follow‐up ranged from no follow‐up to 11 years.

Conclusion.

Surgical excision of submandibular triangle masses is uncommon. We present our experience with these lesions, with a discussion of diagnosis, surgical indications, and surgical complications. © 2004 Wiley Periodicals, Inc. Head Neck 26: 675–680, 2004
Significance of particle interaction to the modelling of cohesive sediment transport in rivers
Authors: Bungartz Heinz , Wanner Susanne C.
Published: May 2004

Aggregation processes of fine sediments have rarely been integrated in numerical simulations of cohesive sediment transport in riverine systems. These processes, however, can significantly alter the hydrodynamic characteristics of suspended particulate matter (SPM), modifying the particle settling velocity, which is one of the most important parameters in modelling suspended sediment dynamics. The present paper presents data from field measurements and an approach to integrate particle aggregation in a hydrodynamic sediment transport model. The aggregation term used represents the interaction of multiple sediment classes (fractions) with corresponding multiple deposition behaviour. The k–ε–turbulence model was used to calculate the coefficient of vertical turbulent mixing needed for the two‐dimensional vertical‐plane simulations. The model has been applied to transport and deposition of tracer particles and natural SPM in a lake‐outlet lowland river (Spree River, Germany). The results of simulations were evaluated by comparison with field data obtained for two levels of river discharge. Experimental data for both discharge levels showed that under the prevailing uniform hydraulic conditions along the river reach, the settling velocity distribution did not change significantly downstream, whereas the amount of SPM declined. It was also shown that higher flow velocities (higher fluid shear) resulted in higher proportions of fast settling SPM fractions. We conclude that in accordance with the respective prevailing turbulence structures, typical aggregation mechanisms occur that continuously generate similar distribution patterns, including particles that settle toward the river bed and thus mainly contribute to the observed decline in the total SPM concentration. In order to determine time‐scales of aggregation and related mass fluxes between the settling velocity fractions, results of model simulations were fitted to experimental data for total SPM concentration and of settling velocity frequency distributions. The comparison with simulations for the case of non‐interacting fractions clearly demonstrated the practical significance of particle interaction for a more realistic modelling of cohesive sediment and contaminant transport. Copyright © 2004 John Wiley & Sons, Ltd.
Multiple objective evaluation of a simple phosphorus transfer model
Authors: Smith Russell M. S. , Wheater Howard S.
Published: May 2004

A simple phosphorus (P) transfer model of the Welland catchment, UK, is evaluated against multiple objective functions using a Monte Carlo approach that combines calibration, identifiability, sensitivity and uncertainty analysis. The model is based on simple conceptual rainfall‐runoff and river routing components, combined with estimates of the daily non‐point source load derived from annual landuse‐based export coefficients, disaggregated as a function of the runoff. The model has limited data requirements, consistent with data availability, and is parsimoneous with respect to the number of parameters identified through inverse modelling. The best performing parameter sets capture the main aspects of the observed flow and total P (TP) concentrations and provide a suitable basis for a decision‐support tool. However, a trade‐off is evident between matching the observed flow peaks, flow recessions and TP concentrations simultaneously, highlighting some limitations of the model structure and/or calibration data. Model analysis indicates that daily non‐point source load cannot be described as a function of near‐surface runoff and land use alone, but that other influences, including seasonality, are important. However, further model development to improve performance is likely to introduce additional complexity (in terms of parameter numbers), and hence additional problems of parameter identifiability and output uncertainty, which in turn raises issues of the information content of the available data. Copyright © 2004 John Wiley & Sons, Ltd.
Hydrological modelling of a small watershed using generated rainfall in the soil and water assessment tool model
Authors: Tripathi M. P. , Panda R. K. , Raghuwanshi N. S. , Singh R.
Published: May 2004

An adequately tested soil and water assessment tool (SWAT) model was applied to the runoff and sediment yield of a small agricultural watershed in eastern India using generated rainfall. The capability of the model for generating rainfall was evaluated for a period of 18 years (1981–1998). The watershed and subwatershed boundaries, drainage networks, slope, soil series and texture maps were generated using a geographical information system (GIS). A supervised classification method was used for land‐use/cover classification from satellite imageries.

Model simulated monthly rainfall for the period of 18 years was compared with observations. Simulated monthly rainfall, runoff and sediment yield values for the monsoon season of 8 years (1991–1998) were also compared with their observed values. In general monthly average rainfall predicted by the model was in close agreement with the observed monthly average values. Also, simulated monthly average values of surface runoff and sediment yield using generated rainfall compared well with observed values during the monsoon season of the years 1991–1998. Results of this study revealed that the SWAT model can generate monthly average rainfall satisfactorily and thereby can produce monthly average values of surface runoff and sediment yield close to the observed values. Therefore, it can be concluded that the SWAT model could be used for developing a multiple year management plan for the critical erosion prone areas of a small watershed. Copyright © 2004 John Wiley & Sons, Ltd.
Effects of the catchment runoff coefficient on the performance of TOPMODEL in rainfall–runoff modelling
Authors: Xiong Lihua , Guo Shenglian
Published: May 2004

Effects of the catchment runoff coefficient on the performance of TOPMODEL in simulating catchment rainfall–runoff relationships are investigated in this paper, with an aim to improve TOPMODEL's simulation efficiency in catchments with a low runoff coefficient. Application of TOPMODEL in the semi‐arid Yihe catchment, with an area of 2623 km2 in the Yellow River basin of China, produced a Nash–Sutcliffe model efficiency of about 80%. To investigate how the catchment runoff coefficient affects the performance of TOPMODEL, the whole observed discharge series of the Yihe catchment is multiplied with a larger‐than‐unity scale factor to obtain an amplified discharge series. Then TOPMODEL is used to simulate the amplified discharge series given the original rainfall and evaporation data. For a set of different scale factors, TOPMODEL efficiency is plotted against the corresponding catchment runoff coefficient and it is found that the efficiency of TOPMODEL increases with the increasing catchment runoff coefficient before reaching a peak (e.g. about 90%); after the peak, however, the efficiency of TOPMODEL decreases with the increasing catchment runoff coefficient. Based on this finding, an approach called the discharge amplification method is proposed to enhance the simulation efficiency of TOPMODEL in rainfall–runoff modelling in catchments with a low runoff coefficient. Copyright © 2004 John Wiley & Sons, Ltd.
Modelling artificial channel and land‐use changes and their impact on floods and sediment yield to the Ishikari basin
Authors: Wongsa Sanit , Shimizu Yasuyuki
Published: May 2004

The potential for flooding and sediment transport is greatly affected by river channel form and changes in land use. Therefore the modelling of channel morphology prior to canalization and of land‐use change is important with respect to the prediction of floods and sediment yield and their consequences. A combination of land‐use transformation maps and soil properties shows certain decision rules for the conversion of forest into arable or vice versa. The model proposed, from this study, was used to simulate possible past and/or future channel and land‐use patterns. Subsequently, the outcome of this simulation was used to assess the risk of flooding, sediment transport and soil‐erosion under different conditions. In this study, channel morphology prior to canalization and land‐use change in the Ishikari basin, Hokkaido, Japan, were analysed by comparing three scenarios using a physical based channel and slope model. The results indicate that pre‐canalization channel morphology has a significant impact on flood peak, but no significant effect on sediment yield. In contrast, land‐use change has a significant effect on soil eroded from hillslopes, but no significant effect on flooding for Ishikari basin. This study also illustrates the challenges that a simple model, such as a physical based channel and slope model, can simulate large‐scale river basin processes using fewer hydrological data resources. Copyright © 2004 John Wiley & Sons, Ltd.
Wetland nitrogen dynamics in an Adirondack forested watershed
Authors: McHale Michael R. , Cirmo Christopher P. , Mitchell Myron J. , McDonnell Jeffrey J.
Published: May 2004

Wetlands often form the transition zone between upland soils and watershed streams, however, stream–wetland interactions and hydrobiogeochemical processes are poorly understood. We measured changes in stream nitrogen (N) through one riparian wetland and one beaver meadow in the Archer Creek watershed in the Adirondack Mountains of New York State, USA from 1 March to 31 July 1996. In the riparian wetland we also measured changes in groundwater N. Groundwater N changed significantly from tension lysimeters at the edge of the peatland to piezometer nests within the peatland. Mean N concentrations at the peatland perimeter were 1·5, 0·5 and 18·6 µmol L−1 for NH4+, NO3− and DON (dissolved organic nitrogen), respectively, whereas peatland groundwater N concentration was 56·9, 1·5 and 31·6 µmol L−1 for NH4+, NO3− and DON, respectively. The mean concentrations of stream water N species at the inlet to the wetlands were 1·5, 10·1 and 16·9 µmol L−1 for NH4+, NO3− and DON, respectively and 1·6, 28·1 and 8·4 µmol L−1 at the wetland outlet. Although groundwater total dissolved N (TDN) concentrations changed more than stream water TDN through the wetlands, hydrological cross‐sections for the peatland showed that wetland groundwater contributed minimally to stream flow during the study period. Therefore, surface water N chemistry was affected more by in‐stream N transformations than by groundwater N transformations because the in‐stream changes, although small, affected a much greater volume of water.

Stream water N input–output budgets indicated that the riparian peatland retained 0·16 mol N ha−1 day−1 of total dissolved N and the beaver meadow retained 0·26 mol N ha−1 day−1 during the study period. Nitrate dominated surface water TDN flux from the wetlands during the spring whereas DON dominated during the summer. This study demonstrates that although groundwater N changed significantly in the riparian peatland, those changes were not reflected in the stream. Consequently, although in‐stream changes of N concentrations were less marked than those in groundwater, they had a greater effect on stream water chemistry—because wetland groundwater contributed minimally to stream flow. Copyright © 2004 John Wiley & Sons, Ltd.
Investigating landfill‐impacted groundwater seepage into headwater streams using stable carbon isotopes
Authors: Atekwana E. A. , Krishnamurthy R. V.
Published: May 2004

The impact of landfill contaminated groundwater along a reach of a small stream adjacent to a municipal landfill was investigated using stable carbon isotopes as a tracer. Groundwater below the stream channel, groundwater seeping into the stream, groundwater from the stream banks and stream water were sampled and analysed for dissolved inorganic carbon (DIC) and the isotope ratio of DIC (δ13CDIC). Representative samples of groundwater seeping into the stream were collected using a device (a ‘seepage well’) specifically designed for collecting samples of groundwater seeping into shallow streams with soft sediments. The DIC and δ13CDIC of water samples ranged from 52 to 205 mg C/L and −16·9 to +5·7‰ relative to VPDB standard, respectively. Groundwater from the stream bank adjacent to the landfill and some samples of groundwater below the stream channel and seepage into the stream showed evidence of δ13C enriched DIC (δ13CDIC = −2·3 to +5·7‰), which we attribute to landfill impact. Stream water and groundwater from the stream bank opposite the landfill did not show evidence of landfill carbon (δ13CDIC = −10·0 to −16·9‰). A simple mixing model using DIC and δ13CDIC showed that groundwater below the stream and groundwater seeping into the stream could be described as a mixture of groundwater with a landfill carbon signature and uncontaminated groundwater. This study suggests that the hyporheic zone at the stream–groundwater interface probably was impacted by landfill contaminated groundwater and may have significant ecological implications for this ecotone. Copyright © 2004 John Wiley & Sons, Ltd.
Snow accumulation in forests from ground and remote‐sensing data
Authors: Lundberg Angela , Nakai Yuichiro , Thunehed Hans , Halldin Sven
Published: May 2004

Winter‐forest processes affect global and local climates. The interception‐sublimation fraction (F) of snowfall in forests is a substantial part of the winter water budget (up to 40%). Climate, weather‐forecast and hydrological modellers incorporate increasingly realistic surface schemes into their models, and algorithms describing snow accumulation and snow‐interception sublimation are now finding their way into these schemes. Spatially variable data for calibration and verification of wintertime dynamics therefore are needed for such modelling schemes. The value of F was determined from snow courses in open and forested areas in Hokkaido, Japan. The value of F was related to species and canopy‐structure measures such as closure, sky‐view fraction (SVF) and leaf‐area index (LAI). Forest structure was deduced from fish‐eye photographs. The value of F showed a strong linear correlation to structure: F = 0·44 − 0·6 × SVF for SVF < 0·72 and F = 0 for SVF > 0·72, and F = 0·11 LAI. These relationships seemed valid for evergreen conifers, larch trees, alder, birch and mixed deciduous stands. Forest snow accumulation (SF) could be estimated from snowfall in open fields (So) and to LAI according to SF = So (1 − 0·11 LAI) as well as from SVF according to SF = So (0·56 + 0·6 SVF) for SVF < 0·72. The value of SF was equal to So for SVF values above 0·72. The value of sky‐view fraction was correlated to the normalized difference snow index (NDSI) using a Landsat‐TM image for observation plots exceeding 1 ha. Variables F and SF were related to NDSI for these plots according to: F = −0·37NDSI + 0·29 and SF = So (0·81 + 0·37NDSI). These relationships are somewhat hypothetical because plot‐size limitation only allowed one sparse‐forest observation of NDSI to be used. There is, therefore, a need to confirm these relationships with further studies. Copyright © 2004 John Wiley & Sons, Ltd.
Multi‐decadal variability of drought risk, eastern Australia
Authors: Kiem Anthony S. , Franks Stewart W.
Published: May 2004

A number of previous studies have identified changes in the climate occurring on decadal to multi‐decadal time‐scales. Recent studies also have revealed multi‐decadal variability in the modulation of the magnitude of El Niño–Southern Oscillation (ENSO) impacts on rainfall and stream flow in Australia and other areas. This study investigates multi‐decadal variability of drought risk by analysing the performance of a water storage reservoir in New South Wales, Australia, during different climate epochs defined using the Inter‐decadal Pacific Oscillation (IPO) index. The performance of the reservoir is also analysed under three adaptive management techniques and these are compared with the reservoir performance using the current ‘reactive’ management practices. The results indicate that IPO modulation of both the magnitude and frequency of ENSO events has the effect of reducing and elevating drought risk on multi‐decadal time‐scales. The results also confirm that adaptive reservoir management techniques, based on ENSO forecasts, can improve drought security and become significantly more important during dry climate epochs. These results have marked implications for improving drought security for water storage reservoirs. Copyright © 2004 John Wiley & Sons, Ltd.
A review of models and micrometeorological methods used to estimate wetland evapotranspiration
Authors: Drexler Judy Z. , Snyder Richard L. , Spano Donatella , Paw U Kyaw Tha
Published: May 2004

Within the past decade or so, the accuracy of evapotranspiration (ET) estimates has improved due to new and increasingly sophisticated methods. Yet despite a plethora of choices concerning methods, estimation of wetland ET remains insufficiently characterized due to the complexity of surface characteristics and the diversity of wetland types. In this review, we present models and micrometeorological methods that have been used to estimate wetland ET and discuss their suitability for particular wetland types. Hydrological, soil monitoring and lysimetric methods to determine ET are not discussed.

Our review shows that, due to the variability and complexity of wetlands, there is no single approach that is the best for estimating wetland ET. Furthermore, there is no single foolproof method to obtain an accurate, independent measure of wetland ET. Because all of the methods reviewed, with the exception of eddy covariance and LIDAR, require measurements of net radiation (Rn) and soil heat flux (G), highly accurate measurements of these energy components are key to improving measurements of wetland ET.

Many of the major methods used to determine ET can be applied successfully to wetlands of uniform vegetation and adequate fetch, however, certain caveats apply. For example, with accurate Rn and G data and small Bowen ratio (β) values, the Bowen ratio energy balance method can give accurate estimates of wetland ET. However, large errors in latent heat flux density can occur near sunrise and sunset when the Bowen ratio β ≈ −1·0. The eddy covariance method provides a direct measurement of latent heat flux density (λE) and sensible heat flux density (H), yet this method requires considerable expertise and expensive instrumentation to implement. A clear advantage of using the eddy covariance method is that λE can be compared with Rn–G–H, thereby allowing for an independent test of accuracy. The surface renewal method is inexpensive to replicate and, therefore, shows particular promise for characterizing variability in ET as a result of spatial heterogeneity. LIDAR is another method that has special utility in a heterogeneous wetland environment, because it provides an integrated value for ET from a surface. The main drawback of LIDAR is the high cost of equipment and the need for an independent ET measure to assess accuracy. If Rn and G are measured accurately, the Priestley–Taylor equation can be used successfully with site‐specific calibration factors to estimate wetland ET. The ‘crop’ cover coefficient (Kc) method can provide accurate wetland ET estimates if calibrated for the environmental and climatic characteristics of a particular area. More complicated equations such as the Penman and Penman–Monteith equations also can be used to estimate wetland ET, but surface variability and lack of information on aerodynamic and surface resistances make use of such equations somewhat questionable. Copyright © 2004 John Wiley & Sons, Ltd.
Intra‐annual variability in the non‐advective heat energy budget of Devon streams and rivers
Authors: Webb B. W. , Zhang Y.
Published: May 2004

The nature of intra‐annual variability in the non‐advective heat fluxes affecting streams and rivers in Devon, UK was investigated through detailed monitoring of study reaches in an upland moorland catchment, below a regulating reservoir, and flowing through deciduous woodland and coniferous forest during the period May 1995 to April 1996. A clear pattern of seasonal variation was evident, whereby net radiation provided a heat source during the summer but a heat sink in the winter, as incoming short‐wave radiation declined and outgoing long‐wave radiation increased. Sensible transfer added heat to the study reaches in the summer but removed it during the winter, and bed conduction acted as a heat sink in the summer period but as a heat source in the winter months. Friction and evaporation added and removed heat, respectively, from the study reaches throughout the year, but the magnitude of these fluxes reflected seasonal variations in discharge and in wind speed. Water temperature generally followed the net non‐advective heat energy budget, which was positive in summer but negative in winter. Although a general pattern of seasonal variability in the non‐advective heat energy budget was evident, detailed differences in the nature and extent of intra‐annual variability were apparent between the study reaches and particularly between forested and non‐forested sites. Copyright © 2004 John Wiley & Sons, Ltd.
Regional daily baseflow prediction
Authors: Tung Ching‐pin , Hong Nien‐ming , Chen Chu‐hui , Tan Yih‐chi
Published: May 2004

The purposes of this study are to identify the bias of applying the analysis of a log–log plot of baseflow and to derive an equation to describe successive regional mean baseflow. The function −dQ/dt = a Qb has been used to describe baseflow in many studies that obtain the values of a and b from the log–log plot. According to analysis in this study, the value of 1 can be assigned to b in two boundary conditions, but the parameter a is proved to be related to the depth of water table and starting time of recession and thus different values of a may be found for different recession events. This paper points out that no single regression line can be obtained by plotting all baseflow data on a log–log diagram. Instead, there should be parallel lines, and each for a recession event. It implies that no single set of parameters a and b can be applied to predict baseflow. Thus, a new equation describing the relationship between three successive mean baseflows was derived in this study. The bias in the analysis of the log–log plot and the ability of the derived equation to predict baseflow were verified for five watersheds in Taiwan. Results indicate that the formula of mean baseflow prediction can provide reasonable estimates of flows with a leading time of 6 days. Furthermore, stream flows of the Tonkawa creek watershed in USA were used to verify that using average flows can result in better predictions than using instantaneous flows. Copyright © 2004 John Wiley & Sons, Ltd.
Experimental study of consolidation properties of unsaturated soils during draining
Authors: Ke Kai‐Yuan , Tan Yih‐Chi , Chen Chu‐Hui , Chim Kin‐Sang , Yeh Tian‐Chyi J.
Published: May 2004

Changes in groundwater elevation may cause a change in the net normal stress and matric potential within the soil mass, which results in volume changes of unsaturated soil. This research investigated the relationship between the drawdown of groundwater and the characteristics of volumetric compressibility of unsaturated soil. Sand column experiments were designed and conducted to measure the volume changes of coarse and fine sands under different types of drainage conditions at fast and slow drainage rates. The finite element programFEMWATERwas calibrated and used to simulate the distributions of stress, tension and moisture content within the sands. Finally, based on the changes of net normal stress and matric potential and the observed volume change of the sands, a least‐square method was applied to determine the volumetric consolidation parameters of the unsaturated soils. Copyright © 2004 John Wiley & Sons, Ltd.
The stemflow of trees in a Bornean lowland tropical forest
Authors: Manfroi Odair J. , Koichiro Kuraji , Nobuaki Tanaka , Masakazu Suzuki , Nakagawa Michiko , Nakashizuka Tohru , Chong Lucy
Published: May 2004

Stemflow volume generation in lowland tropical forests was measured over a 1‐year period in the Malaysian state of Sarawak. The stemflow volume generated by 66 free‐standing trees with a diameter at breast height (DBH) over 1 cm and a tree height over 1 m were measured daily in a representative 10 m × 10 m plot of the forest. Throughfall in the plot was also measured using 20 gauges in a fixed position. Of the 2292 mm of total rainfall observed during the year‐long period, stemflow accounted for 3·5%, throughfall for 82% and there was an interception loss of 14·5%. Understory trees (DBH < 10 cm) played an important role in stemflow generation, producing 77% of the overall stemflow volume and 90% during storms with less than 20 mm of rainfall. Also, owing to their efficiency at funneling rainfall or throughfall water received by their crowns, some understory trees noticeably reduced the catches of the throughfall gauges situated under the reach of their crown areas. During storms producing greater than 20 mm of rainfall, 80% of the total stemflow occurred; trees with a large DBH or height and for which the ratio between crown's diameter and depth is less than 1, tended to generate more stemflow volume in these storms. Mean areal stemflow as a fraction of rainfall in this lowland tropical forest was 3·4%, but may range from 1–10% depending upon the proportion of trees that are high or poor stemflow yielders. Trees with DBH greater than 10 cm were likely to contribute less than 1% of the 3·4% mean areal stemflow in the forest. Copyright © 2004 John Wiley & Sons, Ltd.
Polyethylene glycol–grafted polystyrene particles
Authors: Meng Fenghua , Engbers Gerard H. M. , Feijen Jan
Published: May 2004

Densely pegylated particles that can serve as a model system for artificial cells were prepared by covalently grafting amino polyethylene glycol (PEG, molecular weight 3400 or 5000) onto carboxyl polystyrene particles (PS–COOH) using carbodiimide chemistry. PEG‐modified particles (PS–PEG) were characterized by determination of the PEG surface concentration, ζ‐potential, size, and morphology. Under optimized grafting conditions, a dense “brush‐like” PEG layer was formed. A PEG surface concentration of approximately 60 pmol/cm2, corresponding with an average distance between grafted PEG chains of ∼17 Å can be realized. It was shown that grafting of PEG onto PS–COOH reduced the adsorption of proteins from human plasma (85 vol %) in phosphate‐buffered saline up to 90%. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 49–58, 2004
Evaluation of a resorbable, in situ setting bone substitute in a sheep model
Authors: Niedhart Christopher , Maus Uwe , Piroth Werner , Miltner Oliver , Schmidt‐Rohlfing Bernhard , Siebert Christian H.
Published: May 2004

The gold standard for bone substitution is the autologous bone graft, but because of its limited supply and the associated morbidity, the search for synthetic alternatives is necessary. A new in situ setting tricalcium phosphate cement was implanted in a trepanation defect (9.4 mm diameter, 10 mm depth) in the distal femoral epiphysis of sheep. Empty cavities and autologous bone graft were used as controls. Histologic and histomorphometric examinations were carried out after 12 weeks. Nearly 90% of the implanted cement was resorbed and replaced by ingrown bone with close contact between surrounding bone, new bone, and remaining cement particles. The amount of bone in the defect area was significantly higher in defects filled with cement relative to defects filled with autologous bone graft (mean 27 vs. 21%, 95% confidence intervals 23 to 31 and 18 to 23, p = 0.026). In conclusion, this new in situ setting cement is bioactive, resorbable, and osteoconductive. It will be useful as an alternative to autologous bone graft to fill stable defects. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 123–129, 2004
Effect of filler content on bending properties of dental composites: Numerical simulation with the use of the finite‐element method
Authors: Tanimoto Yasuhiro , Nishiwaki Tsuyoshi , Nemoto Kimiya , Ben Goichi
Published: May 2004

The purpose of this work is to investigate the influence of filler content on the bending properties of dental composites by use of the finite‐element method (FEM). The proposed numerical model was constructed from isotropic shell elements representing silica filler, and isotropic beam elements representing the remaining matrix resin. The proposed model was applied to failure analysis under three‐point bending conditions. The validity of applying the numerical model to the failure progression analysis of composites was checked through comparison with experimental results. The results show that, in both the analytical and experimental results, the bending properties, such as maximum bending stress and bending modulus, increase with filler content. Also, the proposed method of failure progression analysis could better simulate the failure process of composites under three‐point bending conditions. In addition, close agreement between the analytical and experimental results was confirmed. The above results indicate that the proposed numerical model is effective for evaluating the bending properties of dental filler composites of any content range. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 188–195, 2004
The scientifically‐minded psychologist: Science as a core competency
Authors: Bieschke Kathleen J. , Fouad Nadya A. , Collins Frank L. , Halonen Jane S.
Published: May 2004

At the Competencies Conference: Future Directions in Education and Credentialing in Professional Psychology, the Scientific Foundations and Research Competencies Work Group focused on identifying how psychologists practice scientifically. This article presents the subcomponents associated with the core competency of scientific practice. The subcomponents include: 1) access and apply current scientific knowledge habitually and appropriately; 2) contribute to knowledge; 3) critically evaluate interventions and their outcomes; 4) practice vigilance about how sociocultural variables influence scientific practice; and 5) routinely subject work to the scrutiny of colleagues, stakeholders, and the public. In addition, the article briefly discusses how the depth of training for and assessment of each subcomponent will vary by training model. Implications and future directions for individual psychologists, training programs, and the profession are discussed. This is one of a series of articles published in this issue of the Journal of Clinical Psychology. Several other articles that resulted from the Competencies Conference will appear in Professional Psychology: Research and Practice and The Counseling Psychologist. © 2004 Wiley Periodicals, Inc. J Clin Psychol.
Individual and cultural‐diversity competency: Focus on the therapist
Authors: Daniel Jessica Henderson , Roysircar Gargi , Abeles Norman , Boyd Cyndy
Published: May 2004

The Competencies Conference: Future Directions in Education and Credentialing in Professional Psychology was held in Arizona in November 2002. One of the workshops, Individual and Cultural Differences (ICD), focused on racism, homophobia, and ageism. The consensus was that self‐awareness and knowledge about the three “isms” are critical components in the education and training of psychologists. This article, authored by four of the workshop attendees, is a review of the current research and theoretical literature. Implications that address both content and context in graduate programs and training sites are presented. This is one of a series of articles published in this issue of the Journal of Clinical Psychology. Several other articles that resulted from the Competencies Conference will appear in Professional Psychology: Research and Practice and The Counseling Psychologist. © 2004 Wiley Periodicals, Inc. J Clin Psychol.