bluuebunny/crossref_metadata_2025 huggingface dataset:
Nash bargaining over allocations in inventory pooling contracts
Authors: Hanany Eran , Gerchak Yigal
Published: July 2008

When facing uncertain demand, several firms may consider pooling their inventories leading to the emergence of two key contractual issues. How much should each produce or purchase for inventory purposes? How should inventory be allocated when shortages occur to some of the firms? Previously, if the allocations issue was considered, it was undertaken through evaluation of the consequences of an arbitrary priority scheme. We consider both these issues within a Nash bargaining solution (NBS) cooperative framework. The firms may not be risk neutral, hence a nontransferable utility bargaining game is defined. Thus the physical pooling mechanism itself must benefit the firms, even without any monetary transfers. The firms may be asymmetric in the sense of having different unit production costs and unit revenues. Our assumption with respect to shortage allocation is that a firm not suffering from a shortfall, will not be affected by any of the other firms' shortages. For two risk neutral firms, the NBS is shown to award priority on all inventory produced to the firm with higher ratio of unit revenue to unit production cost. Nevertheless, the arrangement is also beneficial for the other firm contributing to the total production. We provide examples of Uniform and Bernoulli demand distributions, for which the problem can be solved analytically. For firms with constant absolute risk aversion, the agreement may not award priority to any firm. Analytically solvable examples allow additional insights, e.g. that higher risk aversion can, for some problem parameters, cause an increase in the sum of quantities produced, which is not the case in a single newsvendor setting. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008
Polyamide 66/EPR‐g‐MA blends: mechanical modeling and kinetic analysis of thermal degradation
Authors: Choudhury Arup , Balmurulikrishnan Ashwini , Sarkhel Gautam
Published: July 2008

The present investigation deals with the mechanical, thermal, and morphological properties of binary nylon 66/maleic anhydride grafted ethylene propylene rubber (EPR‐g‐MA) blends at different dispersed phase (EPR‐g‐MA) concentrations. The effects of EPR‐g‐MA concentration and dispersed particle size on the mechanical properties of the blends were studied. Analysis of the tensile data in terms of various theoretical models revealed the variation of stress concentration effect with blend composition and the improvement of interfacial adhesion between dispersed rubber phase and nylon 66 matrix. The thermal degradation of the blends was analyzed by nonisothermal thermogravimetric analysis (TGA). It was found that the activation energy (Ea) and overall reaction order of thermal degradation decreased with increasing EPR‐g‐MA content. The scanning electron microscopic (SEM) analysis showed a significant decrease in dispersed particle size with increasing EPR‐g‐MA content, which was explained on the basis of the level of chemical interaction (in situ compatibilization) between nylon 66 and EPR‐g‐MA. The surface morphology of the nylon 66/EPR‐g‐MA blends was illustrated by the roughness of atomic force microscopy (AFM) images. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and characterization of sulfonated homo‐ and co‐polyimides based on 2,4 and 2,5‐diaminobenzenesulfonic acid for proton exchange membranes
Authors: Deligöz Hüseyin , Vatansever Sibel , Öksüzömer Faruk , Koç S. Naci , Özgümüş Saadet , Gürkaynak M. Ali
Published: July 2008

A series of sulfonated homo‐ and random co‐polyimides (co‐SPI) based on 2,4‐diaminobenzenesulfonic acid (2,4‐DABS) and 2,5‐diaminobenzenesulfonic acid (2,5‐DABS) has been synthesized via conventional two‐step polyimidization method. 2,4‐DABS and 2,5‐DABS were used as sulfonated diamine compounds, 4,4′‐oxydianiline (ODA) and 4,4′‐diaminodiphenyl sulfone (DDS) were used as non‐sulfonated diamine compounds. Mixtures of sulfonated and non‐sulfonated diamine compounds were reacted with benzophenonetetracarboxylic dianhydride (BTDA) to obtain co‐SPI membranes. Molar ratios of sulfonated to non‐sulfonated diamine were systematically varied to produce copolymers of controlled compositions. The co‐SPIs were evaluated for thermal oxidative stability, ion exchange capacity (IEC), water uptake, proton conductivity, solubility, and hydrolytic stability. Proton conductivity and hydrolytic stability of the co‐SPIs were compared with the fully aromatic polyimide, homo‐SPIs (BTDA/2,4‐DABS and BTDA/2,5‐DABS). Regarding thermogravimetric analysis (TGA) analysis, it is concluded that desulfonation temperature in the range of 200–350°C suggests high stability of sulfonic acid groups. co‐SPIs with 40 mol% of 2,4‐DABS showed similar or higher proton conductivity than Nafion® 117 in water. Proton conductivity values of the co‐SPIs were mainly a function of IEC and water uptake. Consequently, the optimum concentration of 2,4‐DABS was found to be in the range of 30–40 mol% from the viewpoint of proton conductivity, IEC, and hydrolytic stability. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis of ω‐fluorenyl‐functionalized soluble polyphenylene: influence of polymer chain structure on photoluminescence quenching
Authors: Natori Itaru , Natori Shizue , Sekikawa Hiroyuki
Published: July 2008

The influence of the polymer chain structure of soluble polyphenylene (SPP) on the photoluminescence (PL) quenching of fluorene is strongly affected by the 1,2‐phenylene (1,2‐Ph)/1,4‐phenylene (1,4‐Ph) unit molar ratios of SPP, and the amount of 1,4‐Ph units is a major factor for PL quenching. The addition of the fluorenyl group by the formation of carbon–carbon bond at the polymer chain end of SPP is also an important factor for PL quenching of fluorene. Charge (electron) transfer from the fluorenyl end‐group to the main chain of ω‐fluorenyl‐functionalized SPP (FL‐SPP) was very efficient. UV/Vis and PL spectra suggested that this FL‐SPP may be useful for preparing an effective polymer photocell. Copyright © 2008 John Wiley & Sons, Ltd.
DFT studies on the mechanism of Pd(II)‐catalyzed intermolecular 1,2‐diamination of conjugated dienes
Authors: Yu Youqing , Shen Wei , Zhang Jinsheng , He Rongxing , Li Ming
Published: July 2008

The reaction mechanism of the palladium(II)‐catalyzed addition of urea to dienes to form 1,2‐diamine was studied using the B3LYP density functional theory (DFT) method. The results indicate that the first CN σ‐bond formation is the rate‐determining step, and that the covalent bonds are formed favorably by the terminal carbon atoms of dienes and nitrogen atom. The Pd(NCMe)‐catalyst may significantly lower the energy barrier of the rate‐determining step from the nonligand Pd(II)‐catalyst counterpart. The results are in strong support of a recent experiment. Copyright © 2008 John Wiley & Sons, Ltd.
Supramolecular encapsulation of 1,3‐bis(1‐adamantyl)imidazolium chloride by β‐cyclodextrins: towards inhibition of C(2)‐H/D exchange
Authors: Leclercq Loïc , Schmitzer Andreea R.
Published: July 2008

The study of the hydrogen/deuterium exchange reactions of the C(2)‐proton for different carbene precursors has been carried out in the absence and presence of β‐cyclodextrin in D2O at 25°C. Formation of the inclusion complexes of imidazolium salts with the native β‐cyclodextrin and the β‐dimethylcyclodextrin is demonstrated by 1D and 2D 1H NMR, ESI/HRMS and a molecular modelling study. Formation of the inclusion complexes of imidazolium salts with the native β‐cyclodextrin and the β‐dimethylcyclodextrin is a simple and efficient method to modify the acidity of the imidazolium H(2) and to modify its environment. Encapsulation of 1,3‐disubstituted imidazolium chloride by β‐cyclodextrins results in the inhibition of the H(2)/D exchange in the complex. Copyright © 2008 John Wiley & Sons, Ltd.
Chlorination of ammonia and aliphatic amines by Cl2: DFT study of medium and substituent effects
Authors: Vrček Valerije , Meštrić Hrvoje
Published: July 2008

The mechanism of chlorination of ammonia and aliphatic amines by Cl2 was studied by quantum‐chemical calculations using a series of DFT functionals. Three different reaction pathways were considered for the reaction between Cl2 and NH3 in the gas phase. Several intermediates and transition state structures, not described earlier, were located on the corresponding potential energy surface. It is calculated that the reaction field effects (SCIPCM) on the chlorination is much less pronounced than the effect of a specific solvent interaction which was modeled by an explicit water molecule. It is also found that the calculated energy barrier and the reaction free energy of the chlorination of different amines are dependent on the alkyl‐substituent effects. With increase in the basicity of amine, the chlorination reaction becomes more feasible. Calculated geometries of intermediates and overall reaction energetics are significantly influenced by the method for a treatment of electron correlation (DFT vs. MP2), and by the fraction of HF exchange (χ) in DFT functionals. With increase in the χ in the corresponding functional, the DFT results approach those obtained at the MP2 level, and are closer to experimental values, as well. Copyright © 2008 John Wiley & Sons, Ltd.
Aberrant expression of glycosylation in juvenile gastrointestinal stromal tumors
Authors: Takahashi Tsuyoshi , Naka Tetsuji , Fujimoto Minoru , Serada Satoshi , Horino Jirou , Terabe Fumitaka , Hirota Seiichi , Miyoshi. Eiji , Hirai Toshihiro , Nakajima Kiyokazu , Nishitani Akiko , Souma Yoshihito , Sawa Yoshiki , Nishida Toshirou
Published: July 2008

Most adult gastrointestinal stromal tumors (GIST) are thought to be caused by activating mutations in the KIT or PDGFRA gene. However, many juvenile GIST lack either mutation and are considered to develop with a different pathogenesis. To investigate the molecular characteristics of juvenile GIST, we analyzed the proteome difference in phosphorylated protein between adult and juvenile GIST. Eleven GIST samples (seven adult cases and four juvenile cases lacking either mutation) were analyzed by using immunostaining and LC‐MS/MS. Comparative analysis of tyrosine‐phosphorylated protein levels showed that juvenile GIST possessed phosphorylated KIT in spite of lacking mutation in the KIT gene. Moreover, downstream signals of KIT were also activated as in adult GIST. Although, SDS‐PAGE gels showed that there was a difference of each KIT bands between adult and juvenile GIST, they became the same after removal of N‐glycans or sialic acids. Moreover, one of the most typical enzymes, ST6Gal1, which transfers Neu5Ac residues in α2‐6 linkage to Gal β1‐4GlcNAc units on N‐glycans, is significantly less expressed in juvenile GIST. This suggests that the difference in KIT is generated by post‐translational modification and may play a role in the progression of juvenile GIST.
Sample handling for mass spectrometric proteomic investigations of human urine
Authors: Petri Anette Lykke , Høgdall Claus , Christensen Ib Jarle , Simonsen Anja Hviid , T'Jampens Davy , Hellmann Marja‐Leena , Kjaer Susanne Krüger , Fung Eric T. , Høgdall Estrid
Published: July 2008

Because of its non‐invasive sample collection method, human urine is an attractive biological material both for discovering biomarkers and for use in future screening trials for different diseases. Before urine can be used for these applications, standardized protocols for sample handling that optimize protein stability are required. In this explorative study, we examine the influence of different urine collection methods, storage temperatures, storage times, and repetitive freeze‐thaw procedures on the protein profiles obtained by surface‐enhanced laser desorption/ionization time‐of‐flight mass spectrometry (SELDI‐TOF‐MS). Prospectively collected urine samples from 11 women were collected as either morning or midday specimens. The effects of storage temperature, time to freezing, and freeze‐thaw cycles were assessed by calculating the number, intensity, and reproducibility of peaks visualized by SELDI‐TOF‐MS. On the CM10 array, 122 peaks were detected and 28 peaks were found to be significantly different between urine types, storage temperature and time to freezing. On the IMAC‐Cu array, 65 peaks were detected and 1 peak was found to be significantly different according to time to freezing. No significant differences were demonstrated for freeze‐thaw cycles. Optimal handling and storage conditions are necessary in clinical urine proteomic investigations. Collection of urine with a single and consistently performed protocol is needed to reduce analytical bias. Collecting only one urine type, which is stored for a limited period at 4°C until freezing at −80°C prior to analysis will provide the most stable profiles.
MS‐based phenotypic characterization of a human blood protein from urinary waste products
Authors: Kiernan Urban A. , Hernandez Lisa , Niederkofler Eric E. , Tubbs Kemmons A. , Nelson Randall W.
Published: July 2008

The urine proteome (urineome) has become an ideal biological fluid for biomarker study and detection due to its rich protein content as well as its ease and abundance in collection. Protein variation in human plasma has been linked to the presence of disease states in humans; however, it stands to reason that the same is true of the equally complex urineome. In this manuscript we present the combination of two proteomics technologies, mass spectrometric immunoassay and a bioreactive probe, for the detection and characterization of the protein variants of transthyretin (TTR) found in human urine. Coupling these two technologies we could precisely identify protein variants within a population of normal individuals. This is the first report of the detailed characterization of urinary TTR using this combination of proteomic analytical techniques, and demonstrates a novel non‐invasive methodology for the routine analysis of this clinically significant urine protein target.
Urinary proteomic analysis of chronic allograft nephropathy
Authors: O'Riordan Edmond , Orlova Tatyana N. , Mendelev Natalia , Patschan Daniel , Kemp Rowena , Chander Praveen N. , Hu Rena , Hao Gang , Gross Steven S. , Iozzo Renato V. , Delaney Veronica , Goligorsky Michael S.
Published: July 2008

The pathogenesis of progressive renal allograft injury, which is termed chronic allograft nephropathy (CAN), remains obscure and is currently defined by histology. Prospective protocol‐biopsy trials have demonstrated that clinical and standard laboratory tests are insufficiently sensitive indicators of the development and progression of CAN. The study aim was to determine if CAN could be characterized by urinary proteomic data and identify the proteins associated with disease. The urinary proteome of 75 renal transplant recipients and 20 healthy volunteers was analyzed using surface enhanced laser desorption and ionization MS. Patients could be classified into subgroups with normal histology and Banff CAN grades 2‐3 with a sensitivity of 86% and a specificity of 92% by applying the classification algorithm Adaboost to urinary proteomic data. Several urinary proteins associated with advanced CAN were identified including α1‐microglobulin, β2‐microglobulin, prealbumin, and endorepellin, the antiangiogenic C‐terminal fragment of perlecan. Increased urinary endorepellin was confirmed by ELISA and increased tissue expression of the endorepellin/perlecan ratio by immunofluoresence analysis of renal biopsies. In conclusion, analysis of urinary proteomic data has further characterized the more severe CAN grades and identified urinary endorepellin, as a potential biomarker of advanced CAN.
The glomerular proteome in a model of chronic kidney disease
Authors: Potthoff Sebastian A. , Sitek Barbara , Stegbauer Johannes , Schulenborg Thomas , Marcus Katrin , Quack Ivo , Rump Lars C. , Meyer Helmut E. , Stühler Kai , Vonend Oliver
Published: July 2008

Adequate kidney function is crucial in sustaining vertebrate homeostasis. Certain diseases can diminish renal function and lead to end‐stage renal disease. Diabetes mellitus and hypertension are the main causes of glomerulosclerosis and albuminuria in adults. The molecular mechanisms that trigger these maladaptive changes are still unsatisfyingly described. We previously introduced 2‐D DIGE in combination with focused tissue isolation methods to analyze protein expression in glomeruli. Glomeruli, the crucial compartments in albuminuric renal diseases, were extracted using magnetic particles from subtotally nephrectomized FVB mice (n = 6); this 5/6 nephrectomy in FVB mice is a model of chronic kidney disease. Analysis of protein expression levels from glomerular protein lysates was performed using 2‐D DIGE and compared with glomerular protein lysates from mice that underwent sham surgery. The comparison of about 2100 detectable spots between both groups revealed 48 protein spots that showed significant differential expression. Of those, 33 proteins could be identified using nanoLC‐ESI MS. The metalloproteinase meprin 1 alpha, the beta galactoside‐binding‐lectin galectin‐1 and dimethylarginine dimethylaminohydrolase 1, a key enzyme in NO metabolism, were found to be differentially regulated, thus implying a role in the pathogenesis and pathophysiology of progressive kidney disease. In conclusion, 2‐D DIGE protein analysis of smallest sample sizes from specific organ compartments provides focused protein expression results, which help in gaining an understanding of the molecular mechanisms of chronic kidney disease.
Relationship between serum adiponectin and prostate cancer grade
Authors: Sher David J. , Oh William K. , Jacobus Susanna , Regan Meredith M. , Lee Gwo‐Shu , Mantzoros Christos
Published: July 2008

BACKGROUND

Obesity is associated with prostate cancer (PCA) grade, but the mechanism behind this relationship is not understood. Adiponectin is an adipokine that has been linked with the development of hormonally sensitive carcinomas, including prostate cancer. We evaluated the relationship between serum adiponectin and Gleason score (GS) in a prospective series of patients seen in a single institution.

METHODS

Localized PCA patients evaluated at Dana‐Farber Cancer Institute between 2001 and 2005 who enrolled in a prospective serum banking protocol were eligible for this study. Patients with prior hormonal therapy and/or metastatic disease were excluded. High‐grade disease was defined as biopsy or radical prostatectomy (RP) GS of 7 or higher. Logistic regression models were used to assess the relationship between high‐grade disease and adiponectin levels while adjusting for other potential prognostic variables.

RESULTS

There were 539 patients included in this study, of whom 199 had undergone RP. Median age was 60 years. Median PSA was 5.1 ng/dl. Biopsy GS of 7 or higher was seen in 46.9% of patients. For biopsy GS, higher PSA, older age, and higher BMI were significantly associated with increased odds of GS 7 or higher, but adiponectin was not. In men undergoing RP, there was a significant inverse relationship between pathologic GS and adiponectin dichotomized at the median, due to a significantly higher rate of upgrading in patients with lower adiponectin (P = 0.014).

CONCLUSIONS

Although there was no association between biopsy GS and adiponectin, in patients who had undergone RP, lower adiponectin was independently associated with high‐grade prostate cancer. Prostate 68: 1592–1598, 2008. © 2008 Wiley‐Liss, Inc.
Family history of prostate and breast cancer and the risk of prostate cancer in the PSA era
Authors: Chen Yen‐Ching , Page John H. , Chen Rong , Giovannucci Edward
Published: July 2008

BACKGROUND

A family history of prostate cancer (PCa) or breast cancer (BCa) has been associated with the risk of PCa, but the risks were inconsistent in terms of the affected family members, and data in the PSA era are limited.

METHODS

This study included a subcohort of the Health Professionals Follow‐Up Study composed of a highly PSA screened population from 1986 to 2004 with 3,695 PCa cases identified. Questionnaires and a food frequency questionnaire were administered every other and every 4 years, respectively. Family history of PCa and BCa was ascertained in 1990, 1992, and 1996. All statistics were two‐sided.

RESULTS

A family history of PCa in both a father and brother(s) was associated with a 2.3‐fold increased risk of PCa [95% confidence interval (CI) = 1.76–3.12]. Men with a father or brother(s) with a PCa diagnosis at age<60 and ≥60 had 2.16‐ and 1.95‐fold increased risk of PCa, respectively. A family history of PCa was related to early‐onset PCa (<65 years: RR = 2.25, 95% CI = 1.95–2.60) and weakly to late‐onset PCa (≥65 years: RR = 1.67, 95% CI = 1.52–1.85). History of BCa in a mother or a sister was associated with a 1.22‐fold increased risk of PCa (95% CI = 1.08–1.38).

CONCLUSION

A family history of PCa or BCa significantly increases PCa risk. These associations are evident in a population with widespread PSA screening. Prostate 68: 1582–1591, 2008. © 2008 Wiley‐Liss, Inc.
Theoretical models for doping diamond for semiconductor applications
Authors: Goss J. P. , Eyre R. J. , Briddon P. R.
Published: July 2008

Diamond is a material with superlative properties in terms of carrier mobilities and device characteristics for high power electronics applications. Although p‐type diamond is routinely available using boron, n‐type material via impurity doping during the growth of diamond has historically been limited in success, partly because nitrogen is a hyper‐deep donor, but compounded by the compact lattice leading to low solubilities for alternative species. Implantation doping is often hampered by persistent residual damage leading to significant levels of compensation and the formation of dopant complexes with lattice vacancies. Experiment has been augmented by the application of quantum‐chemical methods to assess the likely properties should specific impurities or impurity complexes be realisable in real materials. The review outlines many of the doping strategies explored for diamond, including simple impurity doping and co‐doping. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recombination of free and bound excitons in GaN
Authors: Monemar B. , Paskov P. P. , Bergman J. P. , Toropov A. A. , Shubina T. V. , Malinauskas T. , Usui A.
Published: July 2008

We report on recent optical investigations of free and bound exciton properties in bulk GaN. In order to obtain reliable data it is important to use low defect density samples of low doping. We have used thick GaN layers (of the order of 1 mm) grown by halide vapour phase epitaxy (HVPE) with a residual doping down to <1016 cm–3 in this work. With such samples all polarisation geometries could also easily be exploited. The influence of the surface states on the photoluminescence (PL) experiments is analysed, it is concluded that surface recombination plays an important role for the free exciton (FE) recombination. The electronic structure of the FEs is discussed in detail, including the influence of spin‐exchange and polariton effects, and compared with polarised PL spectra at 2 K. The detailed structure of excited states from the PL spectra is discussed, but further data are needed to fully explain all the peaks observed. The polarized FE spectra at room temperature allow a determination of the bandgap as 3.437 eV at 290 K, assuming an exciton binding energy of 25 meV. The PL transient of the A FE is very short (about 100 ps) for the no‐phonon (NP) line interpreted as dominated by nonradiative surface recombination. The longitudinal‐optical (LO) phonon replicas of the A FE exhibit a longer decay of about 1.4 ns at 2 K, suggested to represent the bulk lifetime of the FE. The corresponding decay time at 290 K is 9 ns in our samples, a value that might be affected by nonradiative recombination. The Si and O donor bound exciton (DBE) spectra with sharp NP lines at 3.4723 eV and 3.4714 eV respectively, are well resolved together with the so‐called two‐electron transitions (TETs) and several optical phonon replicas. The electronic structure of the DBE states including excited rotational states is discussed and compared with experiment. The well‐resolved TET lines allow an accurate determination of the ground state binding energy of the Si donor as 30.4 meV and 33.2 meV for the O donor. The PL transients of the DBEs reveal a non‐exponential decay for the NP lines. The DBE NP transient lineshape is assumed to be influenced by optical dispersion and scattering in the vicinity of exciton resonances, as well as by surface effects. The DBE decay time can most properly be deduced from the PL decay of the respective TETs and LO replicas, leading to values in the range of 1.1–1.8 ns. These values differ significantly from previous theoretical predictions, where values about two orders of magnitude shorter were obtained. A tentative discussion of the main observed features of acceptor bound excitons (ABEs), which are much less studied in GaN, is given. A decay time of about 0.9 ns for the shallowest 3.466 eV ABE is estimated, i.e. shorter than that for the shallow donor BEs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First principles calculations of the magnetic properties of Fe–N systems
Authors: Li Dan , Roh Jong Wook , Jeon Kye Jin , Gu You Song , Lee Wooyoung
Published: July 2008

We report the results of the first principles calculations performed in order to investigate the electronic and magnetic properties of the Fe–N systems and to clarify the origin of giant magnetic moments in Fe–N systems. After geometrical optimization, the densities of states have been evaluated with atom resolved band populations and magnetic moments. By examining Fe–N bond lengths in the Fe–N systems, it was found that there is a linear relationship between Fe–N bond lengths and atomic magnetic moments. Our results demonstrate that the existence of N atoms can affect charge transfer between the 4s, 4p and 3d bands of Fe atoms and is responsible for the change in magnetic moments. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scientific literacy: A Freirean perspective as a radical view of humanistic science education
Authors: Santos Wildson L. P. Dos
Published: July 2008

In this article, a rationale for advancing a new idea in humanistic science education is developed from a Paulo Freire perspective. Paulo Freire developed a well‐known approach to adult literacy based on his humanistic ideas through the dialogical process. From Freirean educational principles, the idea unfolds that a Freirean humanistic science education perspective is a political commitment to sociopolitical action, considering conditions of oppression in society. Although some humanistic science education approaches to school science have incorporated a sociopolitical perspective, it is showed that not all of them necessarily focus on the political purpose of transforming oppressive conditions in society as stressed by Paulo Freire. From this Freirean humanistic perspective, an approach to science education is then highlighted, which implies the introduction of socially relevant themes and socioscientific issues, the establishment of a dialogical process in classroom, and the development of sociopolitical action. Hence, a Freirean perspective of science education is presented as a radical view of scientific literacy. Some implications of a Freirean approach to science education are outlined at the end of the paper. © 2008 Wiley Periodicals, Inc.Sci Ed93:361–382, 2009
Social barriers to meaningful engagement in biology field trip group work
Authors: Anderson David , Thomas Gregory P. , Nashon Samson M.
Published: July 2008

This paper reports on a study that employed metacognition and social cognition theoretical frameworks to explore and interpret students' views of their cognitive roles and the nature of the mechanisms that they considered influenced and mediated their learning within small group contexts. An instrumental interpretive case study methodology was used to capture students' descriptive accounts of their Year 11 Biology learning experiences, as conveyed through their recollections and reflections concerning their interactions and roles, perceptions of the learning task, and their learning strategies that they considered to be manifest during a field trip visit to a nature center. We conclude that, even among apparently highly collegial student groups, deemed by their teacher to be effective learning groups, and constituted in ways consistent with the literature on effective collaborative group work, there existed metasocial metacognitive factors that influenced and shaped cognition in ways counterproductive to the effective learning of science. This study reveals the existence of metacognitive knowledge and processes, common among students and related to their views of what is appropriate thinking and behavior within small groups, which inform collective and individual task actions. We contend that students are highly aware of their social status within groups and of their individual group's social conditions and that this awareness affects cognition and behavior. Moreover, they monitor these conditions and employ strategies that simultaneously service both the task and social relationships and their learning processes to varying extents depending on individual and group factors. © 2008 Wiley Periodicals, Inc. Sci Ed 93: 511–534, 2009
Mechanism of carbon nanotube dispersion and precipitation during treatment with poly(acrylic acid)
Authors: Tran N. H. , Milev A. S. , Wilson M. A. , Bartlett J. R. , Kannangara G. S. K.
Published: July 2008

Carbon nanotubes have been shown to be easily dispersed within an acidic aqueous solution of poly(acrylic acid) but precipitate when the pH is increased. Transmission electron microscopy showed that the nanotubes were more exfoliated under the acidic condition but highly aggregated under the basic condition. Carbon K‐edge NEXAFS spectroscopy showed that the carbon nanotubes did not chemically react with poly(acrylic acid) during the dispersion or precipitation and that the dispersion mainly involved physical adsorption of poly(acrylic acid) onto the nanotubes. Together with the carbon K‐edge NEXAFS spectra, the cobalt L3, 2‐edge NEXAFS spectra suggested that under the basic condition, the cobalt impurity within the nanotubes strongly reacted with poly(acrylic acid) resulting in complex formation. Cobalt reduces the adsorption of poly(acrylic acid) onto the nanotubes, which then reduced the nanotube dispersion and resulted in the precipitation. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of Cu pre‐deposition on the interface structure between the C‐SiC coatings and stainless steel
Authors: Du J. F. , Yang S. Q. , Ren D. , Zhang R. Q. , Huang N. K.
Published: July 2008

The copper dispersion‐strengthened matrix composites (Cu/CSiC) were fabricated on the stainless steel by using magnetron sputtering and ion‐beam mixing. The pre‐deposition of Cu element is used to modify the interface structure, and hence, to develop the compatibility between Fe substrate and C‐SiC coating. The results show that the copper layer can effectively broaden the transition layer, where the elements of the coating could be completely mixed with the elements of the substrate. The following heat treatment on it can further broaden the transition layer, i.e. heat treatment can provide more compatibility between C‐SiC coating and Fe substrate. Copyright © 2008 John Wiley & Sons, Ltd.
Surface morphology of Ge‐modified 3C‐SiC/Si films
Authors: Nader Richard , Kazan Michel , Moussaed Elie , Stauden Thomas , Niebelschütz Merten , Masri Pierre , Pezoldt Jörg
Published: July 2008

The influence of Ge deposition prior to carbon interaction with 3° off‐axis Si(111) substrates on the structural and morphological properties of the formed silicon carbide (SiC) layer is studied. In situ reflection high‐energy electron diffraction (RHEED) and X‐ray diffraction (XRD) revealed the formation of the cubic silicon carbide (3C‐SiC) modification. In situ spectroscopic ellipsometry measurements revealed a decreasing 3C‐SiC thickness with increasing Ge predeposition. Atomic force microscopy (AFM) studies revealed that the surface overlayer morphology is mainly formed by periodic step arrangements whose relevant geometric parameters, i.e. lateral separation, height and terrace width, depend on the Ge content. Besides the changes of the step morphology, the surface roughness and the grain size and the strain of the formed 3C‐SiC decreases with increasing germanium precoverage. Copyright © 2008 John Wiley & Sons, Ltd.
Disordered state of adsorbed hydrogens on Ni(111) surface studied by slow‐positron beam
Authors: Komagata S. , Hirota K. , Arii S. , Kanazawa I. , Fukutani K. , Nozawa K. , Komori F.
Published: July 2008

The positron annihilation γ‐ray energy spectra emitted from hydrogen‐lightly adsorbed Ni(111) surface and hydrogen‐saturatedly adsorbed one are analyzed. We have discussed the disordered state of hydrogen‐saturatedly adsorbed Ni(111) surface. Copyright © 2008 John Wiley & Sons, Ltd.
Theoretical study of NO adsorption/dissociation on Pd (100) and (111) surfaces
Authors: Jia Xiang Feng , Yu Shuai Qin , Wang Ze Xin , Ma Yongshan
Published: July 2008

Both adsorption and dissociation of the diatomic molecular NO on Pd (100) and (111) surfaces are studied using the extended London‐Eyring‐Polyani‐Sato (LEPS) method constructed by means of 5‐MP (the 5‐parameter Morse potential). All critical characteristics of the system that we obtain, such as adsorption geometry, binding energy, eigenvalues for vibration, are in good agreement with the experimental results. On Pd (100) surface, NO prefers to adsorb in fourfold hollow site (H) uprightly at low coverage. With increase in the coverage NO gradually tilts in fourfold hollow and bridge sites. For NOPd (111) system, two adsorption states are found at low coverage, of which one adsorption state is the B(tilt) state that the centroid of NO projects at bridge site, another (HBH state) that NO almost parallels to the (111) surface with the vibration frequency of 610 cm−1, but the frequency is near to that of the atoms, which is easy to be ignored in experiments. At high coverage, two transitional states (BH and HT) are found. NO is difficult to dissociate on Pd (100) and (111) surfaces. Especially for NOPd (111) system, the three‐well‐potential dissociation mode is initially put forward to show the remarkable dissociation process with two dissociation transitional states of NO on Pd (111). Copyright © 2008 John Wiley & Sons, Ltd.
Private Law Models for Public Law Concepts: The Roman Law Theory of Dominium in the Monarchomach Doctrine of Popular Sovereignty
Authors: Lee Daniel
Published: July 2008

The essay traces the juridical origins of the modern doctrine of popular sovereignty as developed by the monarchomach jurists of the late sixteenth century. Particularly, the use of doctrines from the Roman law of property explains the sovereign right of the people to resist and reconstitute the commonwealth. Reviving the civilian concept of dominium during the French Wars of Religion and dynastic royal politics, these radical jurists articulated the claim that the people, not kings, have property rights over the commonwealth. By conceptualizing the people corporately as property-owners in this way, they were able to draw on legal arguments from Roman law to justify popular resistance as an assertion of a corporate property right. In doing so, the monarchomachs expressed an elaborate theory of state and sovereignty within the grammar of the Roman private law.
Political Membership in the Contractarian Defense of Cosmopolitanism
Authors: Ypi Lea
Published: July 2008

This article assesses the recent use of contractarian strategies for the justification of cosmopolitan distributive principles. It deals in particular with the cosmopolitan critique of political membership and tries to reject the claim that political communities are arbitrary for the scope of global justice. By focusing on the circumstances of justice, the nature of the parties, the veil of ignorance, and the sense of justice, the article tries to show that the cosmopolitan critique of political membership modifies the contractarian premises in a way that is both unwarranted and unnecessary. While failing to establish principles of global distributive justice, existing cosmopolitan adaptations of the social contract device simply weaken the method's justificatory potential.
Eros and Moderation in Plutarch'sLife of Solon
Authors: Hertzoff Andrew
Published: July 2008

Plutarch is generally not considered a philosopher in his own right. However, a careful reading of his life of Solon, the Athenian lawgiver, in conjunction with an examination of his philosophical essays, shows that Plutarch is engaged in a debate with Epicureans and Stoics whose misjudgments of the worth and limits of human passions lead them knowingly or unknowingly to draw lines between the happy philosophical life and the life of politics. Through the life of Solon, Plutarch demonstrates how a philosopher would actually engage in politics, and with his proper understanding of human nature, educate that society through wise laws that encourage a moderate and healthy form of erotic life in the city. In doing so, Plutarch makes a case for a substantive contribution of Platonic philosophy to the guidance of the statesman.
Democratizing Dialectics with C.L.R. James
Authors: Douglas Andrew J.
Published: July 2008

This essay explores the work of C.L.R. James in an effort to rethink the democratic import of dialectical thought. James is best known as a West Indian Marxist and the author of The Black Jacobins, but he is also a deeply democratic thinker and a creative reader of Hegel. Alongside the more orthodox Marxist strand of his thought, James develops a mode of dialectical reflection that is attentive to a sense of democratic uncertainty and that aims to enrich political participation among ordinary citizens. By thinking both with and against James, and by exploiting the ambiguities in his postwar writings on dialectics and American democratic culture, I argue that James inspires a kind of participatory democratic ethos grounded in the language and conceptual resources of Hegelian humanist thought and modern dialectical reflection.
Body sensor calibration and construction of 3D maps for robot navigation using the framework of conformal geometric algebra
Authors: López-Franco C. , Bayro-Corrochano E.
Published: July 2008

The research, described in this paper, concerns the robot indoor navigation, emphasizing the aspects of sensor model and calibration, environment representation, and self-localization. The main point is that combining all of these aspects, an effective navigation system is obtained. We present a model of the catadioptric image formation process. Our model simplifies the operations needed in the catadioptric image process. Once we know the model of the catadioptric sensor, we have to calibrate it with respect to the other sensors of the robot, in order to be able to fuse their information. When the sensors are mounted on a robot arm, we can use the hand-eye calibration algorithm to calibrate them. In our case the sensors are mounted on a mobile robot that moves over a flat floor, thus the sensors have less degrees of freedom. For this reason we develop a calibration algorithm for sensors mounted on a mobile robot. Finally, combining all the previous results and a scan matching algorithm that we develop, we build 3D maps of the environment. These maps are used for the self-localization of the robot and to carry out path following tasks. In this work we present experiments which show the effectiveness of the proposed algorithms.
European archaeology. An inclusive or exclusive discipline?
Authors: Kohl Philip L.
Published: July 2008

Let me begin with an anecdote: in summer 1985 Karl Lamberg-Karlovsky and I participated in Bronze Age excavations at the site of Sarazm along the middle Zeravshan river in what was then Soviet Tajikistan. I remember one of the Russian artists on the dig complaining ruefully (and patronizingly) about her Tajik colleagues. ‘When will they [that is, her Tajik colleagues] ever become like us Russians and Americans, you know, Europeans?’ Karl, who is very proud of his mixed Czech, Slovak, and Austrian heritage, snorted disdainfully: ‘Since when have Americans and Russians ever been European?’
There is no archaeology but European archaeology . . .
Authors: Meier Thomas
Published: July 2008

To start with, I would like to emphasize that I very much agree with most points of Kristian Kristiansen's analysis of the European state of archaeology. In my view he is totally right in observing a turn from the global perspective to a national and local focus, expressed not least by narrowing language capabilities and restricted citation networks, both convincingly described in his paper. Furthermore he is right, I think, that archaeology has lost importance in the academic field due to its general avoidance of the grand questions, while at the same time the reviving myths of origin and heritage have prompted an unseen public interest in archaeology on the local level.
European heritage. A view from the periphery
Authors: Pearce Mark
Published: July 2008

In this stimulating piece Kristiansen provides a trenchant critique of the provincialism of much European archaeology (though he tends to concentrate his argument on prehistory), but he does not really engage with the question of whether we need an archaeology of Europe until his closing paragraphs. Here his answer is that ‘Europe and its regions [are] a far better and less exclusive frame of reference than the dominant local and national framework’ (p. NN) – i.e. we need an archaeology of Europe not to exclude others but in order to transcend narrow provincialism. Like Kristiansen, I too would like to put off engaging with the question, and start by examining his argument.
Frontiers of the Roman Empire
Authors: Breeze David J.
Published: July 2008

While not a formal comment on Kristiansen's discussion paper, this brief note was written and submitted to Archaeological dialogues by a participant in the discussions between the Zadar Round Table speakers and the audience.
The dialectic between global and local perspectives in archaeological theory, heritage and publications
Authors: Kristiansen Kristian
Published: July 2008

When I agreed to present the article as a vehicle for discussion at a session at the EAA's annual meeting in Zadar, Croatia, I decided to approach the question of a European archaeology from what I considered to be the three organizing pillars of archaeological practice: heritage, theory and publications. Heritage is the dominant organizational/legislative framework for archaeological practice, and it is where most of the money is spent. Theory, on the other hand, organizes most of our interpretations of the past, while publications are still the most common way of presenting the results of both heritage work (mostly excavations) and interpretations of that work. In this way I hoped to have encircled the dominant parameters for a diagnosis of the archaeological landscapes in Europe. I assumed that there might be some correlation between the three, and that such observed common trends within two or more variables would strengthen the argument, to paraphrase processual jargon.
MEAN-VALUE PROPERTY ON MANIFOLDS WITH MINIMAL HOROSPHERES
Authors: TODJIHOUNDE LEONARD
Published: July 2008

Let (M,g) be a non-compact and complete Riemannian manifold with minimal horospheres and infinite injectivity radius. In this paper we prove that bounded functions on (M,g) satisfying the mean-value property are constant. We thus extend a result of Ranjan and Shah [‘Harmonic manifolds with minimal horospheres’, J. Geom. Anal.12(4) (2002), 683–694] where they proved a similar result for bounded harmonic functions on harmonic manifolds with minimal horospheres.
MIXED NORM ESTIMATES FOR POTENTIAL OPERATORS RELATED TO THE RADON TRANSFORM
Authors: DUOANDIKOETXEA JAVIER , ORUETXEBARRIA OSANE
Published: July 2008

We define potential operators on hyperplanes and give sharp mixed norm inequalities for them. One of the operators coincides with the Radon transform for which mixed norm estimates are known but in reverse order. Those inequalities will be crucial in our proofs.
I0 SETS FOR COMPACT, CONNECTED GROUPS: INTERPOLATION WITH MEASURES THAT ARE NONNEGATIVE OR OF SMALL SUPPORT
Authors: GRAHAM COLIN C. , HARE KATHRYN E.
Published: July 2008

In the dual object of an infinite compact, connected group, every infinite Sidon set contains an infinite subset on which full interpolation can be performed using very small classes of measures (discrete measures on arbitrarily small sets or nonnegative discrete measures). In particular, the Figà-Talamanca–Rider subset of an infinite product of compact, connected, simple Lie groups has these kinds of interpolation. This substantially improves previous interpolation results.
A PARABOLIC SINGULAR INTEGRAL OPERATOR WITH ROUGH KERNEL
Authors: CHEN YANPING , DING YONG , FAN DASHAN
Published: July 2008

Let Ω(y′) be an H1(Sn−1) function on the unit sphere satisfying a certain cancellation condition. We study the Lp boundedness of the singular integral operator where α≥n and ρ is a norm function which is homogeneous with respect to certain nonistropic dilation. The result in the paper substantially improves and extends some known results.
THE SPECTRA OF THE SPHERICAL AND EUCLIDEAN TRIANGLE GROUPS
Authors: HARMER MARK
Published: July 2008

We derive the spectrum of the Laplace–Beltrami operator on the quotient orbifold of the nonhyperbolic triangle groups.
A PROOF OF ISBELL’S ZIGZAG THEOREM
Authors: HOFFMAN PIOTR
Published: July 2008

We provide a short, intuitive proof of Isbell’s zigzag theorem.
Power of magnetopause low‐frequency waves: A statistical study
Authors: Attié D. , Rezeau L. , Belmont G. , Cornilleau‐Wehrlin N. , Lucek E.
Published: July 2008

ULF fluctuations at the Earth magnetopause have been the subject of a long‐standing interest because of their noticeable amplitude and their potential role in plasma penetration through the magnetosphere boundary. Some information on the nature of these fluctuations has already been provided thanks to GEOS and ISEE, and more recently Cluster, case studies and from a few statistical studies on magnetopause crossings. Here we present a new statistical study concerning the power of the ultralow frequency fluctuations based on the data of the Cluster‐STAFF experiment. New insight in the properties of turbulence is obtained, because of the orbit of the Cluster spacecraft, which gives access to regions far from the subsolar point. The correlation of the wave power with solar wind and magnetosheath properties indicates that these fluctuations are controlled and possibly driven by external sources. Its correlation with the magnetopause properties (namely the magnetic shear angle) provides an indication of an amplification process at the boundary.
Infragravity waves in the deep ocean: Generation, propagation, and seismic hum excitation
Authors: Uchiyama Yusuke , McWilliams James C.
Published: July 2008

Oceanic infragravity waves are investigated as a possible source of seismic free oscillations, often referred to as the “hum” of the Earth, using a numerical model of depth‐independent, nondispersive, long‐wave dynamics with a forcing from nonlinear interactions among the primary wind waves (including swell). Because of near‐resonant amplification, the structure of the primary‐wave forcing field in shallow water, and an edge‐trapping mechanism, infragravity waves are excited very effectively near the coasts. Deep‐water infragravity waves are significantly influenced both by offshore leakage and propagation of the coastally generated free waves and by deep‐water primary‐wave forcing. With the inclusion of “mesoscale” variability on top of the more slowly varying primary waves generated in synoptic storms, the deep‐water infragravity waves are found to have an amplitude on the order of a millimeter in height, which is consistent with field observations and considered to be sufficient to account for local hum excitation in the middle of the basin.