bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Resolution Prediction of Enhanced Condensate Recovery Processes
Authors: Jessen K. , Gerritsen M. G. , Mallison B. T.
Published: July 2008

This paper investigates the accuracy of first- and high-order numerical methods in simulating enhanced condensate processes in 1D, 2D, and 3D. We compare the predictions of a standard single point upwind (SPU) scheme with a third-order accurate finite difference (FD) simulator based on a third-order essentially nonoscil-latory (ENO) flux reconstruction with matching temporal accuracy. We include physical dispersion in the mathematical model of these multiphase, multicomponent systems.

The comparisons demonstrate that SPU schemes may fail to predict the formation of the mobile liquid bank at the leading edge of the displacement unless an impractical number of gridblocks is used in the simulations. In contrast, the high-order FD simulator is demonstrated to accurately predict the liquid bank at much lower grid resolution, providing for a more efficient simulation approach. In 2D displacement calculations with gravity included, the CPU requirement of the SPU scheme was found to be more than 50 times larger than for the ENO scheme for a given level of accuracy. In 2D vertical cross-sections, the predicted component recovery is demonstrated to vary upward of 8% depending on the selected numerical scheme for a given grid resolution and disper-sivity. In these settings, the SPU solutions converge to the ENO results upon significant grid refinement.

In 3D displacement calculations, the magnitude ofthe predicted condensate bank is also found to be very different depending on the selected numerical scheme. Relative to the 2D displacement calculations, condensate banking and gravity segregation is observed to have less impact on the process performance prediction because of the permeability configuration in the 3D model used here, but it could have a high impact in different settings.

We include an explicit representation of longitudinal and transverse dispersion in the porous medium to demonstrate the grid resolution required to resolve physical dispersion at a given simulation length scale, and to show that condensate banks can also form in more realistic dispersive systems. Grid-refinement studies in 1D and 2D demonstrate, again, that the ENO scheme outperforms the SPU scheme for a given Peclet (Pe) number. Converged solutions are obtained with the ENO scheme using a relatively small number of grid cells. In addition, we show the behavior of the two schemes for varying Peclet numbers on a fixed simulation grid. For this grid, the ENO scheme is shown to be sensitive to the Peclet number, signifying that physical dispersion is not overwhelmed by numerical diffusion. For the SPU scheme, however, the solutions are almost independent of the Peclet number, which indicates that numerical diffusion dominates.
Laboratory Investigation of the Effect of Solvent Injection on In-Situ Combustion
Authors: Cristofari J. , Castanier L. M. , Kovscek A. R.
Published: July 2008

Application of cyclic solvent injection into heavy and viscous crude oil followed by in-situ combustion of heavy residues is explored from a laboratory perspective. The solvent reduces oil viscosity in-situ and extracts the lighter crude-oil fractions. Combustion cleans the near-well region and stimulates thermally the oil production. Both solvent injection and in-situ combustion are technically effective. The combination of the two methods, however, has never been tried to our knowledge.

Hamaca (Venezuela) and West Sak (Alaska) crude oils were employed. First, ramped temperature oxidation studies were conducted to measure the kinetic properties of the oil prior to and following solvent injection. Pentane, decane, and kerosene were the solvents of interest. Second, solvent was injected in a cyclic fashion into a 1-m-long combustion tube. Then, the tube was combusted. Hamaca oil presented good burning properties, especially following pentane injection. The pentane extracted lighter components of the crude and deposited preferentially effective fuel for combustion. On the other hand, West Sak oil did not exhibit stable combustion properties without solvent injection, following solvent injection, and even when metallic additives were added to enhance the combustion. We were unable to propagate a burning front within the combustion tube. Nevertheless, the experimental results do show that this combined solvent combustion method is applicable to the broad range of oil reservoirs with properties similar to Hamaca.
The Politics of Asymmetrical Federalism: Reconsidering the Role and Responsibilities of Ottawa
Authors: Brock Kathy L.
Published: July 2008

This article argues that while asymmetrical arrangements among the units of any federation are necessary and even desirable, federal encroachments on provincial jurisdiction in Canada over the past few decades have triggered a protective impulse in the provinces that has resulted in a multiplication of deals recognizing provincial differences. The nature and variety of such arrangements are undermining the sense of federal comity, goodwill, and understanding so critical to national unity. To avoid heading further down this trajectory and attenuating the bonds that hold the nation together, the federal government should reconsider its role in the federation. While the current Conservative government policy of open federalism begins this reconceptualization of federal and provincial roles and responsibilities, more constructive and principled action is required.
What Explains the Canada-US Labour Productivity Gap?
Authors: Rao Someshwar , Tang Jianmin , Wang Weimin
Published: July 2008

This paper analyzes the reasons for the Canada-US labour productivity gap, which is mainly explained by the multifactor productivity (MFP) gap. Based on panel data for 41 industries, the regression results show that differences in the machinery and equipment (M&E) capital-labour ratio, trade openness, and capacity utilization explain differences in the Canada-US MFP gap across industries. The M&E capital intensity gap is the dominant source of the MFP gap. Lower wages, R&D intensity, and skills levels, as well as higher investment goods prices in Canada are the major determinants of the M&E capital intensity gap.
Immigration Wave Effects on Canada's Trade Flows
Authors: Partridge Jamie , Furtan Hartley
Published: July 2008

We utilize an enhanced gravity model to estimate the effect of lagged immigration waves on Canadian imports and exports by province. Empirically, this model was tested using Canadian data on import and export flows to the top 40 countries of origin for Canadian immigrants based upon the composition of the most recent immigrant wave. The results are consistent with previous studies, where immigrants increased both import and export trade flows. By adding the provincial immigrant wave variable, it was also found that new immigrants affect imports almost immediately, whereas for exports, the immigrant effect is not significant for at least five years and may take as long as 20 years to reach full impact.
Neighbourhood Effects in Canada:A Critique
Authors: Oreopoulos Philip
Published: July 2008

A growing number of researchers and policy-makers concern themselves with the possible effects of living in areas with high concentrations of poverty. This paper provides an overview of such literature from a Canadian policy perspective. I draw three conclusions. First, household exposure to concentrated poverty is substantially less than in the United States. Second, much of the existing Canadian research on neighbourhood effects relies on regression analysis, which is prone to bias and misinterpretation. Third, the most persuasive research to date suggests that residential environment matters most to an individual's mental health and exposure to crime, but has little influence on self-sufficiency or child development. Smaller spheres of interaction, such as at the classroom or roommate level, appear to matter more.
One‐Step Synthesis of Conducting Polymer–Noble Metal Nanoparticle Composites using an Ionic Liquid
Authors: Pringle Jennifer M. , Winther‐Jensen (née Ngamna) Orawan , Lynam Carol , Wallace Gordon G. , Forsyth Maria , MacFarlane Douglas R.
Published: July 2008

Conducting polymers containing incorporated gold or silver nanoparticles have been synthesized using ionic liquid solutions of gold chloride or silver nitrate. Use of the metal salts as the oxidant for monomers such as pyrrole and terthiophene allows the composites to be formed in one simple step, without the need for templates or capping agents. The incorporated metal nanoparticles are clearly visible by TEM, and the composites have been further analyzed by TGA, CV, UV‐Vis, Raman, XPS and scanning TEM coupled with EDS analysis. Utilization of an ionic liquid allows the full oxidizing power of the gold chloride to be accessed, resulting in incorporation of metallic gold into the polymers.
A Unique Processable Green Polymer with a Transmissive Oxidized State for Realization of Potential RGB‐Based Electrochromic Device Applications
Authors: Gunbas Gorkem E. , Durmus Asuman , Toppare Levent
Published: July 2008

Realization of commercial RGB‐based polymer electrochromic‐device applications can only be achieved by processable materials that possess three complementary colors in the reduced state and are transparent in the oxidized state. This report highlights the synthesis of the first processable green polymer with a transmissive oxidized state. The polymer revealed superior optical contrast in the visible region with fast switching times and robust stability. Hence, this material is the outstanding candidate for completion of RGB color space through commercial polymeric electrochromics.
The Relation Between Open‐Circuit Voltage and the Onset of Photocurrent Generation by Charge‐Transfer Absorption in Polymer : Fullerene Bulk Heterojunction Solar Cells
Authors: Vandewal Koen , Gadisa Abay , Oosterbaan Wibren D. , Bertho Sabine , Banishoeib Fateme , Van Severen Ineke , Lutsen Laurence , Cleij Thomas J. , Vanderzande Dirk , Manca Jean V.
Published: July 2008

Photocurrent generation by charge‐transfer (CT) absorption is detected in a range of conjugated polymer–[6,6]‐phenyl C61 butyric acid methyl ester (PCBM) based solar cells. The low intensity CT absorption bands are observed using a highly sensitive measurement of the external quantum efficiency (EQE) spectrum by means of Fourier‐transform photocurrent spectroscopy (FTPS). The presence of these CT bands implies the formation of weak ground‐state charge‐transfer complexes in the studied polymer–fullerene blends. The effective band gap (Eg) of the material blends used in these photovoltaic devices is determined from the energetic onset of the photocurrent generated by CT absorption. It is shown that for all devices, under various preparation conditions, the open‐circuit voltage (Voc) scales linearly with Eg. The redshift of the CT band upon thermal annealing of regioregular poly(3‐hexylthiophene):PCBM and thermal aging of poly(phenylenevinylene)(PPV):PCBM photovoltaic devices correlates with the observed drop in open‐circuit voltage of high‐temperature treated versus untreated devices. Increasing the weight fraction of PCBM also results in a redshift of Eg, proportional with the observed changes in Voc for different PPV:PCBM ratios. As Eg corresponds with the effective bandgap of the material blends, a measurement of the EQE spectrum by FTPS allows us to measure this energy directly on photovoltaic devices, and makes it a valuable technique in the study of organic bulk heterojunction solar cells.
Optical Properties and Growth Aspects of Silver Nanoprisms Produced by a Highly Reproducible and Rapid Synthesis at Room Temperature
Authors: Aherne Damian , Ledwith Deirdre M. , Gara Matthew , Kelly John M.
Published: July 2008

A rapid and readily reproducible seed‐based method for the production of high quality silver nanoprisms in high yield is presented. The edge‐length and the position of the main plasmon resonance of the nanoprisms can be readily controlled through adjustment of reaction conditions. From UV‐vis spectra of solutions of the nanoprisms, the inhomogeneously broadened line width of the in‐plane dipole plasmon resonance is measured and trends in the extent of plasmon damping as a function of plasmon resonance energy and nanoprism size have been elucidated. In addition, an in‐depth analysis of the lamellar defect structure of silver nanoprisms is provided that confirms that the defects can lead to a transformation of the crystal structure in the vicinity of the defects. These defects can combine give rise to lamellar regions, thicker than 1 nm, that extend across the crystal, where the silver atoms are arranged in a continuous hexagonal‐close‐packed (hcp) structure. This hcp structure has a periodicity of 2.50 Å, thus explaining the 2.50 Å lattice fringes that are commonly observed in 〈111〉 oriented flat‐lying nanoprisms. A new understanding of the mechanisms behind anisotropic growth in silver nanoprisms is presented.
A Template‐Free Method Towards Conducting Polymer Nanostructures
Authors: Wan Meixiang
Published: July 2008

Conducting polymer nanostructures have recently received special attention in nanoscience and nanotechnology because of their highly π‐conjugated polymeric chains and metal‐like conductivity, such that they can be regarded not only as excellent molecular wires, but also as basic units for the formation of nanodevices. Although various approaches, such as hard‐template methods, soft‐template methods, electrospinning technology, and so on are widely employed to synthesize or fabricate conducting polymer nanostructures and their composite nanostructures, each of the currently used methods possess disadvantages. Therefore, finding a facile, efficient, and controlled method of forming conducting polymer nanostructures is desirable. Similar to other nanomaterials, the effect of size (in these cases 1–100 nm) on the properties of the conducting polymer nanostructures must be considered. Electrical measurements of single nanotubes or nanowires are desirable in order to be able to understand the pure electrical properties of conducting polymer nanostructures. Compared with bulk conducting polymers, conducting polymer nanostructures are expected to display improved performance in technological applications because of the unique properties arising from their nanometer‐scaled size: high conductivity, large surface area, and light weight. Thus, it is also desirable to develop promising applications for conducting polymer nanostructures. In accordance with the issues described above, our research focuses on a new synthesis method to form conducting polymer nanostructures and on the related formation mechanism of the resultant nanostructures. The electrical and transport properties of single nanotubes of conducting polymer, measured by a four‐probe method, and promising applications of such template‐free‐synthesized conducting polymer nanostructures as new microwave absorbing materials and sensors guided by a reversible wettability are also of interest. This article reports some of our main results and reviews some important contributions of others.

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Promising Functional Materials Based on Ladder Polysiloxanes
Authors: Zhou Qilong , Yan Shouke , Han Charles C. , Xie Ping , Zhang Rongben
Published: July 2008

Preparation of real ladder polysiloxanes (LPSs), including both oxygen‐bridged ladder polysilsesquioxanes (LPSQs) and organo‐bridged ladder polysiloxanes (OLPSs), had been a great challenge to polymer chemists from 1960 until the successful synthesis of LPSs via the supramolecular architecture‐directed stepwise coupling polymerization (SCP) in the early 1980s. This opened up a new field of LPS‐based advanced materials. As key building blocks, LPSs are used to construct a variety of polysiloxanes with special steric configurations and functions, such as mesomorphic LPSs, tubular polysiloxanes (TPs), and pseudo‐sieve‐plate polysiloxanes (pseudo‐SPSs). With excellent temperature and radiation resistance, good solubility, and fine optical and mechanical properties, all these polysiloxanes demonstrate very promising prospects in the advanced materials realm. Here, the synthesis of well‐ordered LPSs is presented and features of fishbone‐like and rowboat‐like liquid crystalline polysiloxanes are discussed. Special emphasis is given to typical applications of LPSs, TPSs, and pseudo‐SPSs in the areas of liquid crystal displays, microelectronics packaging, and nonlinear optical materials.
Self‐Similar Growth of Polyolefin Alloy Particles in a Single Granule Multi‐Catalyst Reactor
Authors: Du Jiang , Niu Hui , Dong Jin‐Yong , Dong Xia , Han Charles C.
Published: July 2008

In this news article, a new kind of in‐reactor alloying process (Chinese multi‐catalyst reactor granule technology, CMRGT) is introduced. It provides the possibility to produce series of new polyolefin materials that can be used in automotive and appliances parts by the substitution of some traditional engineering plastics. A characteristic ‘fractal (self‐similar) growth and pore‐filling mechanism’ for the CMRGT‐produced alloy particles is found. It reveals the fundamental scientific principles that govern the chemistry and physics in the formation mechanism of such novel olefinic alloys. This mechanism allows a detailed control of the dispersion and structure of these polyolefin alloys from a nanometer to micrometer size range, and possesses great potential to fulfil the requirements for a new generation of recyclable automotive materials.
Fabrication of Low‐Dimension Nanostructures Based on Organic Conjugated Molecules
Authors: Cui Shuang , Liu Huibiao , Gan Liangbing , Li Yuliang , Zhu Daoben
Published: July 2008

The aim of this review is to explore the fundamental and technological incentive for the molecular design, synthesis, and aggregation behavior of conjugated organic molecules with photo‐electronic activity, and the fabrication of low‐dimensional organic conjugated nanomaterials by self‐assembly techniques. The properties of large oriented nanostructure arrays of organic charge transfer complexes based on conjugated molecules are also discussed. The dimension‐dependent emission properties have been observed, and conductivity, field emission properties, and sensing properties have been studied for the low dimensional nanostructures of nanoparticles, nanowires, nanorods, and nanostructure arrays.

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Fluorescent Conjugated Polyelectrolytes for Biomacromolecule Detection
Authors: Feng Fude , He Fang , An Lingling , Wang Shu , Li Yuliang , Zhu Daoben
Published: July 2008

Water‐soluble conjugated polymers have attracted much attention in the biosensor community because of recent exciting experimental results. The transfer of excitation energy along the whole backbone of the conjugated polymer to the reporter results in an amplified fluorescence signal, which makes them useful as optical platforms in highly sensitive chemical and biological sensors. In this Research News Article, we provide a brief review of recent developments in this field, focusing especially on the application of water‐soluble optical conjugated polymers in biomacromolecule (DNA and protein) detection.
Template Synthesis of Hierarchically Structured Composites
Authors: Wei Wei , Yang Zhenzhong
Published: July 2008

The subtle performance of a virus is closely related to its specific hierarchical structure, which is composed of a rigid shell and transverse, responsive, nanometer‐sized channels. Virus‐like structured colloids are of great interest for their potential applications, for example in drug delivery. Adequate knowledge of the structure and composition control of both colloids and mesoporous materials is significant in the design and synthesis of hierarchically structured colloids to mimic viruses. Some recent developments in the synthesis of composite colloids and mesoporous materials are summarized. Template synthesis is a major tool to control both the macroscopic morphology and microstructures of these composites, in which gel colloids and supramolecular structures from amphiphilic species are used as templates.

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Chemoenzymatic Approach to Enantiomerically Pure (R)‐3‐Hydroxy‐3‐methyl‐4‐pentenoic Acid Ester and Its Application to a Formal Total Synthesis of Taurospongin A
Authors: Fujino Aya , Sugai Takeshi
Published: July 2008

(R)‐3‐Hydroxy‐3‐methyl‐5‐hexanoic acid p‐methoxybenzyl ester 1b was prepared by carbon‐chain elongation on both termini of the starting material, (R)‐3‐benzyloxy‐2‐methylpropane‐1,2‐diol 2a, which was prepared by an over‐expressed Bacillus subtilis epoxide hydrolase‐catalyzed enantioselective hydrolysis of the racemic 1‐benzyloxymethyl‐1‐methyloxirane 3. One of the key steps of the requisite transformation was the Rhodococcus rhodochrous NBRC 15564‐mediated hydrolysis of a cyano group to a carboxyl group under neutral conditions, to exclude any racemization of the intermediate and/or product. The enantiomerically pure form of (R)‐1b was applied to a new formal total synthesis of taurospongin A.
Integrating parameter selection with experimental design under uncertainty for nonlinear dynamic systems
Authors: Chu Yunfei , Hahn Juergen
Published: July 2008

Models describing complex processes often contain a large number of parameters as part of the nonlinear system. It is usually not possible in practice to identify all parameters because of the number and quality of measurement data as well as interactions among the parameters. A common approach is to select a set of parameters for estimation whereas other parameters are fixed at their nominal values. Such a parameter selection procedure is often based on sensitivity analysis; however, the determined sensitivity values depend on assumed values of the parameters and initial states, as well as known trajectories of the input signals. In this work parameter selection and experiment design procedures are integrated into a unified framework, which optimizes a criterion of the Fisher information matrix and simultaneously takes the effect of uncertainty in the parameter values into account. A hybrid method combining a genetic algorithm and a simultaneous perturbation stochastic approximation is developed to solve the resulting mixed‐integer nonlinear programming problem. The technique is illustrated on a model of a continuously‐stirred tank reactor and of a signal transduction pathway. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Suggestive linkage on chromosome 2, 8, and 17 for lifetime major depression
Authors: Middeldorp Christel M. , Sullivan Patrick F. , Wray Naomi R. , Hottenga Jouke‐Jan , de Geus Eco J.C. , van den Berg Mireille , Montgomery Grant W. , Coventry Will L. , Statham Dixie J. , Andrews Gavin , Slagboom P. Eline , Boomsma Dorret I. , Martin Nicholas G.
Published: July 2008

It is well established that major depressive disorder (MDD) is partly heritable. We present a genome‐wide linkage study aiming to find regions on the genome that influence the vulnerability for MDD. Our sample consists of 110 Australian and 23 Dutch pedigrees with two or more siblings affected with MDD (total N = 278). Linkage analysis was carried out in MERLIN. Three regions showed suggestive linkage signals. The highest LOD‐score of 2.1 was found on chromosome 17 at 52.6 cM along with LOD scores of 1.9 and 1.7 on chromosome 8 at 2.7 cM and chromosome 2 at 90.6 cM, respectively. The result on chromosome 8 seems most promising as two previous studies also found linkage in this region, once suggestive and once significant. The linkage peak on chromosome 17 harbors the serotonin transporter gene. In the Australian and Dutch sample, the serotonin transporter length polymorphism did not show evidence for association, thus other genes in this region or other polymorphisms in the serotonin transporter gene might be associated with MDD. Further replication is needed to establish the relevance of our linkage finding on chromosome 2. © 2008 Wiley‐Liss, Inc.
Novel de novo SHANK3 mutation in autistic patients
Authors: Gauthier Julie , Spiegelman Dan , Piton Amélie , Lafrenière Ronald G. , Laurent Sandra , St‐Onge Judith , Lapointe Line , Hamdan Fadi F. , Cossette Patrick , Mottron Laurent , Fombonne Éric , Joober Ridha , Marineau Claude , Drapeau Pierre , Rouleau Guy A.
Published: July 2008

A number of studies have confirmed that genetic factors play an important role in autism spectrum disorder (ASD). More recently de novo mutations in the SHANK3 gene, a synaptic scaffolding protein, have been associated with the ASD phenotype. As part of our gene discovery strategy, we sequenced the SHANK3 gene in a cohort of 427 ASD subjects and 190 controls. Here, we report the identification of two putative causative mutations: one being a de novo deletion at an intronic donor splice site and one missense transmitted from an epileptic father. We were able to confirm the deleterious effect of the splice site deletion by RT‐PCR using mRNA extracted from cultured lymphoblastoid cells. The missense mutation, a leucine to proline at amino acid position 68, is perfectly conserved across all species examined, and would be predicted to disrupt an alpha‐helical domain. These results further support the role of SHANK3 gene disruption in the etiology of ASD. © 2008 Wiley‐Liss, Inc.
DRD2 C32806T modifies the effect of child‐rearing environment on adulthood novelty seeking
Authors: Keltikangas‐Järvinen Liisa , Pulkki‐Råback Laura , Elovainio Marko , Raitakari Olli. T. , Viikari Jorma , Lehtimäki Terho
Published: July 2008

Preliminary evidence suggests that there may be longitudinal interactions between environmental and genetic factors in predicting Novelty seeking. We have previously found in small and selected subsample from the Cardiovascular Risk in Young Finns study, that an association between the polymorphism of dopamine receptor D4 was moderated by the childhood environment, as indexed by hostile maternal child‐rearing. We wanted to replicate this finding in a population based sample of 1,114 men and women using another candidate gene of dopaminergic system, that is, the dopamine receptor D2 (DRD2). The child‐rearing environment of the participants was assessed by their mothers when the participants were children or adolescents, and adulthood Novelty seeking was self‐rated by the participants 17 and 21 years later at the ages of 24–39. Genotyping of DRD2 C32806T (rs 1800497) was performed using TaqMan 5′nuclease assay. DRD2 was not directly associated with Novelty seeking, but there was a significant DRD2 × strict maternal disciplinary style interaction in predicting Novelty seeking (F = 7.08, P = 0.008). The interaction showed that when the child‐rearing environment was punitive, participants carrying any A1 allele of the DRD2 gene had higher scores on Novelty seeking than carriers of the A2/A2 genotype. The genotype had no effect on Novelty seeking when the childhood environment was more favorable. The findings suggest that the DRD2 may have an environmentally moderated impact on Novelty seeking and that the origins of such an association may lie already in childhood. © 2008 Wiley‐Liss, Inc.
Peaceful Post‐Conflict Interactions between Aggressors and Bystanders in captive lowland gorillas (Gorilla gorilla gorilla)
Authors: Palagi Elisabetta , Chiarugi Elena , Cordoni Giada
Published: July 2008

We observed a colony of lowland gorillas in order to assess the occurrence of Peaceful Post‐Conflict Interactions between Aggressors and Bystanders (PPIAB). We compared the dynamics of PPIAB with those of Peaceful Post‐Conflict Interactions between Victims and Bystanders (PPIVB), which are directed toward victims. We confirmed the occurrence of PPIAB (mean Triadic Contact Tendency: 41.7%±16.2% SEM) at frequencies comparable to PPIVB. Immature gorillas were responsible for most PPIAB. PPIAB occurred when the bystander was unrelated to either the aggressor or the victim, and when it was a relative of the aggressor. However, affinitive contact rates were higher in the former case. Unlike PPIVB, PPIAB significantly reduced the likelihood of further aggressions within the group, suggesting that they work at an immediate level. Our data also suggest that bystanders decide when a peaceful contact may be too risky; in fact, neither PPIAB nor PPIVB occurred after high‐intensity aggressions. Am. J. Primatol. 70:949–955, 2008. © 2008 Wiley‐Liss, Inc.
Factors affecting fecal glucocorticoid levels in semi‐free‐ranging female mandrills (Mandrillus sphinx)
Authors: Setchell Joanna M , Smith Tessa , Wickings E Jean , Knapp Leslie A
Published: July 2008

Subordinate female cercopithecine primates often experience decreased reproductive success in comparison with high‐ranking females, with a later age at sexual maturity and first reproduction and/or longer interbirth intervals. One explanation that has traditionally been advanced to explain this is high levels of chronic social stress in subordinates, resulting from agonistic and aggressive interactions and leading to higher basal levels of glucocorticoids. We assessed the relationships among fecal cortisol levels and reproductive condition, dominance rank, degree of social support, and fertility in female mandrills (Mandrillus sphinx) living in a semi‐free‐ranging colony in Franceville, Gabon. Lower‐ranking females in this colony have a reproductive disadvantage relative to higher‐ranking females, and we were interested in determining whether this relationship between dominance rank and reproductive success is mediated through stress hormones. We analyzed 340 fecal samples from 19 females, collected over a 14‐month period. We found that pregnant females experienced higher fecal cortisol levels than cycling or lactating females. This is similar to results for other primate species and is likely owing to increased metabolic demands and interactions between the hypothalamus–pituitary–adrenal axis, estrogen, and placental production of corticotrophin releasing hormones during pregnancy. There was no influence of dominance rank on fecal cortisol levels, suggesting that subordinate females do not suffer chronic stress. This may be because female mandrills have a stable social hierarchy, with low levels of aggression and high social support. However, we found no relationship between matriline size, as a measure of social support, and fecal cortisol levels. Subordinates may be able to avoid aggression from dominants in the large enclosure or may react only transiently to specific aggressive events, rather than continuously expecting them. Finally, we found no relationship between fecal cortisol levels and fertility. There was no difference in fecal cortisol levels between conceptive and nonconceptive cycles, and no significant relationship between fecal cortisol level and either the length of postpartum amenorrhea or the number of cycles before conception. This suggests that the influence of dominance rank on female reproductive success in this population is not mediated through chronic stress in subordinate females, and that alternative explanations of the relationship between social rank and reproduction should be sought. Am. J. Primatol. 70:1023–1032, 2008. © 2008 Wiley‐Liss, Inc.
Isotopic and dental evidence for infant and young child feeding practices in an imperial Roman skeletal sample
Authors: Prowse Tracy L. , Saunders Shelley R. , Schwarcz Henry P. , Garnsey Peter , Macchiarelli Roberto , Bondioli Luca
Published: July 2008

This study integrates isotopic, palaeopathological, and historical evidence to investigate infant and young child feeding practices in a Roman period (1st to 3rd centuries AD) skeletal sample from the Isola Sacra necropolis (Rome, Italy). Stable isotope analysis of bone collagen from 37 rib samples indicates that transitional feeding began by the end of the first year and weaning occurred by 2–2.5 years of age. Both δ15N and δ13C data clearly show the trophic level effect associated with breastfeeding. Childhood diet is investigated using dental pathology data in the deciduous dentitions of 78 individuals aged between 1 and 12 years. The presence of calculus, caries, and tooth wear in young children suggests that individuals were provided complementary foods and other items that impacted their dental health at an early age. The isotopic and dental data are generally consistent with the historical evidence from the Roman period with respect to the general timetable of weaning and the character of complementary foods. This is the first study to integrate isotopic and deciduous dental pathology data to explore infant and young child feeding practices in the Roman world. Am J Phys Anthropol 2008. © 2008 Wiley‐Liss, Inc.
Greater sciatic notch as a sex indicator in juveniles
Authors: Vlak Dejana , Roksandic Mirjana , Schillaci Michael A.
Published: July 2008

Using Schutkowski's method for juvenile sex determination (Schutkowski H. 1993. Am J Phys Anthropol 90:199–205), we evaluated the morphology of the greater sciatic notch of 56 ilia (23 females and 33 males) from a documented skeletal collection housed at the Bocage Museum in Lisbon (Portugal). After applying Schutkowski's original methodology and comparing the results with previous studies, we used age‐adjusted metrical variables to describe greater sciatic notch depth, breadth, and angle. Although results of both morphological and metrical analyses did not reveal a statistically significant level of sexual analyses dimorphism, we found a strong correlation between pelvic morphology and age at death. On the basis of the obtained results, we argue that Schutkowski's morphological method does not predict sex accurately in all populations and that recorded correlation of iliac features with age needs to be further explored in the context of the ontogeny of sexual dimorphism. Am J Phys Anthropol 2008. © 2008 Wiley‐Liss, Inc.
Dental crown size and sex hormone concentrations: Another look at the development of sexual dimorphism
Authors: Guatelli‐Steinberg Debbie , Sciulli Paul W. , Betsinger Tracy K.
Published: July 2008

Previous researchers hypothesized that tooth types forming during early childhood should be less sexually dimorphic than those forming during later childhood, if sex hormone concentration differences between males and females increase progressively throughout childhood and can affect tooth size. Descriptive tooth size data have recently been cited in support of this hypothesis, particularly with respect to differences in sexual dimorphism among the tooth types of tooth classes. The present study tests this hypothesis for the mesiodistal dimension of human permanent teeth using published data for incisor, premolar, and molar tooth classes from seven diverse populations. The sample size for each tooth type per population was at least 50. This study also tests a modification of this hypothesis which takes into account the postnatal testosterone surge in males and the low levels of sex hormones in both sexes prior to puberty. Predictions are developed for both the original and modified hypotheses. The “D” statistic, the total area of nonoverlap between the phenotypic distributions of males and females, is used to quantify sexual dimorphism. Comparison of D values for different tooth types within tooth classes across these seven populations does not strongly support either hypothesis. These results suggest that gross changes in sex hormone concentrations during development are not related to population‐wide patterns of sexual dimorphism among the tooth types of human permanent tooth classes, as recent studies indicate. This finding is consistent with other studies which suggest that sex hormones have only a minor role in generating crown size sexual dimorphism. Am J Phys Anthropol 2008. © 2008 Wiley‐Liss, Inc.
Cheek pouch use, predation risk, and feeding competition in blue monkeys (Cercopithecus mitis stuhlmanni)
Authors: Smith Lindsey W. , Link Andres , Cords Marina
Published: July 2008

The adaptive function of cheek pouches in the primate subfamily Cercopithecinae remains unresolved. By analyzing the circumstances of cheek pouch use, we tested two hypotheses for the evolution of cercopithecine cheek pouches proposed in earlier studies: (1) cheek pouches reduce vulnerability to predation, and (2) cheek pouches increase feeding efficiency by reducing competition. We studied two groups of wild blue monkeys (Cercopithecus mitis stuhlmanni) in the Kakamega Forest, Kenya, conducting focal observations of feeding individuals. Monkeys were less exposed while emptying their cheek pouches than filling them, supporting the predation‐avoidance hypothesis. We investigated several measures of competitive threat, but only one supported the competition‐reduction hypothesis: when the nearest neighbor's rank increased, subjects were more likely to increase than to decrease cheek pouch use. Overall, our findings supported the predation‐avoidance hypothesis more strongly than the competition‐reduction hypothesis. We suggest that variation in cheek pouch use may reflect differing behavioral strategies used by cercopithecines to mitigate competition and predation, as well as factors such as resource size and distribution, home range size, and travel patterns. Am J Phys Anthropol 2008. © 2008 Wiley‐Liss, Inc.
Modern humans are not (quite) isometric
Authors: Sylvester Adam D. , Kramer Patricia A. , Jungers William L.
Published: July 2008

Allometric relationships are important sources of information for many types of anthropological and biological research. The baseline for all allometric relationships is isometry (or geometric similarity), the principal that shape is invariant of size. Here, we formally test for geometric similarity in modern humans, looking at the maximum lengths of four long bones (humerus, radius, femur, and tibia). We use Jolicoeur's multivariate allometry method to examine globally distributed samples of human populations, both collectively and individually. Results indicate that humans are not geometrically similar, although morphological deviations from isometry are small. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
Basics in paleodemography: A comparison of age indicators applied to the early medieval skeletal sample of Lauchheim
Authors: Wittwer‐Backofen Ursula , Buckberry Jo , Czarnetzki Alfred , Doppler Stefanie , Grupe Gisela , Hotz Gerhard , Kemkes Ariane , Larsen Clark Spencer , Prince Debbie , Wahl Joachim , Fabig Alexander , Weise Svenja
Published: July 2008

Recent advances in the methods of skeletal age estimation have rekindled interest in their applicability to paleodemography. The current study contributes to the discussion by applying several long established as well as recently developed or refined aging methods to a subsample of 121 adult skeletons from the early medieval cemetery of Lauchheim. The skeletal remains were analyzed by 13 independent observers using a variety of aging techniques (complex method and other multimethod approaches, Transition Analysis, cranial suture closure, auricular surface method, osteon density method, tooth root translucency measurement, and tooth cementum annulation counting). The age ranges and mean age estimations were compared and results indicate that all methods showed smaller age ranges for the younger individuals, but broader age ranges for the older age groups. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
Genetic history of Southeast Asian populations as revealed by ancient and modern human mitochondrial DNA analysis
Authors: Lertrit Patcharee , Poolsuwan Samerchai , Thosarat Rachanie , Sanpachudayan Thitima , Boonyarit Hathaichanoke , Chinpaisal Chatchai , Suktitipat Bhoom
Published: July 2008

The 360 base‐pair fragment in HVS‐1 of the mitochondrial genome were determined from ancient human remains excavated at Noen U‐loke and Ban Lum‐Khao, two Bronze and Iron Age archaeological sites in Northeastern Thailand, radio‐carbon dated to circa 3,500–1,500 years BP and 3,200–2,400 years BP, respectively. These two neighboring populations were parts of early agricultural communities prevailing in northeastern Thailand from the fourth millennium BP onwards. The nucleotide sequences of these ancient samples were compared with the sequences of modern samples from various ethnic populations of East and Southeast Asia, encompassing four major linguistic affiliations (Altaic, Sino‐Tibetan, Tai‐Kadai, and Austroasiatic), to investigate the genetic relationships and history among them. The two ancient samples were most closely related to each other, and next most closely related to the Chao‐Bon, an Austroasiatic‐speaking group living near the archaeological sites, suggesting that the genetic continuum may have persisted since prehistoric times in situ among the native, perhaps Austroasiatic‐speaking population. Tai‐Kadai groups formed close affinities among themselves, with a tendency to be more closely related to other Southeast Asian populations than to populations from further north. The Tai‐Kadai groups were relatively distant from all groups that have presumably been in Southeast Asia for longer‐that is, the two ancient groups and the Austroasiatic‐speaking groups, with the exception of the Khmer group. This finding is compatible with the known history of the Thais: their late arrival in Southeast Asia from southern China after the 10th–11th century AD, followed by a period of subjugation under the Khmers. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
Der Weg zu nichtenzymatischen molekularen Netzwerken
Authors: Dadon Zehavit , Wagner Nathaniel , Ashkenasy Gonen
Published: July 2008

Dieser Kurzaufsatz gibt einen Überblick über aktuelle Fortschritte auf dem Gebiet der Konstruktion und der Analyse von chemischen Systemen, die templatgelenkte autokatalytische und kreuzkatalytische Vorgänge als Mittel zum Verknüpfen dynamisch wechselwirkender Moleküle einsetzen. Dabei werden synthetische Netzwerke aus zwei bis neun replizierenden Einheiten erörtert, und es wird gezeigt, dass bei größeren Systemen mehr katalytische Wege beeinflusst werden müssen, um die Gesamttopologie des Netzwerks und die Funktionalität der einzelnen Einheiten oder Unternetzwerke zu beherrschen. Die Zellbiochemie ist ein Beispiel für ein natürliches funktionales molekulares Netzwerk. Synthetische selbstorganisierte Netzwerke können zusätzliche Modelle für komplexere Systeme bereitstellen.
The First cis‐Dioxido Uranyl Compound under Scrutiny
Authors: Villiers Claude , Thuéry Pierre , Ephritikhine Michel
Published: July 2008

The identity of a cis‐dioxido uranyl compound recently reported by P. B. Duval et al., is questioned on the basis of the structural characterization of three other compounds obtained using the reported reactants.
Study of epoxy toughened by in situ formed rubber nanoparticles
Authors: Ma Jun , Mo Mao‐Song , Du Xu‐Sheng , Dai Shao‐Rong , Luck Ian
Published: July 2008

The effect of rubber nanoparticles on mechanical properties and fracture toughness was investigated. Rubber nanoparticles of 2–3 nm were in situ synthesized in epoxy taking advantage of the reaction of an oligomer diamine with epoxy. The chemical reaction was verified by gel permeation chromatography (GPC) and 1HNMR, and the microstructure was characterized by transmission electron microscope. The rubber nanoparticles caused much less Young's modulus deterioration but toughened epoxy to a similar degree in comparison with their peer liquid rubber that formed microscale particles during curing. Fifteen wt % of rubber nanoparticles increased fracture energy from 140 to 840 J/m2 with Young's modulus loss from 2.85 to 2.49 GPa. The toughening mechanism might be the stress relaxation of the matrix epoxy leading to larger plastic work absorbed at the crack tip; there is no particle cavitation or deformation; neither crack deflection nor particle bridging were observed. The compound containing rubber nanoparticles demonstrates Newtonian liquid behavior with increasing shear rate; it shows lower initial viscosity at low shear rate than neat epoxy; this provides supplementary evidence to NMR and GPC result. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Carboxymethyl tamarind: Synthesis, characterization and its application as novel drug‐delivery agent
Authors: Pal Sagar , Sen G. , Mishra S. , Dey R. K. , Jha U.
Published: July 2008

Carboxymethylated tamarind (CMT) has been synthesized by reacting tamarind kernel powder (TKP) with sodium salt of monochloro acetic acid (SMCA) in the presence of sodium hydroxide. This new material was characterized by a variety of materials characterization techniques, namely intrinsic viscosity measurement, FTIR spectroscopy, 13C NMR spectra, thermal studies (TGA and DTA), static light scattering (SLS) technique for determination of weight average molecular weight and elemental analysis (C, H, N and O). The material thus developed was studied for its suitability as a matrix for controlled drug delivery. The kinetics of Drug release was also undertaken. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of a Hindered Amine Stabilizer (HAS) on radiolytic and thermal stability of poly(methyl methacrylate)
Authors: Aquino Katia Aparecida S. , Araujo Elmo S.
Published: July 2008

Commercial Poly(methyl methacrylate) (PMMA) containing Tinuvin 622, a Hindered Amine Stabilizer (HAS), in 0.3% (wt/wt) concentration was investigated. The samples were irradiated with gamma radiation (60Co) at room temperature in air. The viscosity‐average molecular weight (Mv) was analyzed by viscosity technique. Both control PMMA (without HAS) and PMMA + 622 (with HAS) showed a decrease in molecular weight with the increase in dose, reflecting the random scissions that occurred in the main chain. The G value (scissions/100 eV of energy transferred to the system) was also obtained by viscosity analysis. G value results showed that the addition of Tinuvin 622 into the PMMA matrix significantly decreased the number of scissions/100 eV at dose range of 0–60 kGy. Analysis of infrared spectra showed a decrease in the carbonyl index (CI) in irradiated samples. However the CI decrease was found lower for PMMA + 622 than for control PMMA sample. Thermogravimetric analysis (TGA) revealed that maximum decomposition temperature of additive PMMA is 42°C higher than control PMMA for unirradiated system. On the other hand this difference is not significant in irradiated systems at 60‐kGy irradiation dose. The activation energy of the thermal degradation of PMMA was 165 kJ/mol, this activation energy increased 60 kJ/mol when Tinuvin 622 was added to PMMA matrix. Therefore Tinuvin 622 is a suitable radiostabilizing agent for commercial PMMA in a 0–60 kGy dose interval. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of neutron irradiation on the structural, mechanical, and thermal properties of jute fiber
Authors: Sinha E. , Rout S. K.
Published: July 2008

This article describes the effect of neutron irradiation on jute fiber (Corchorus olitorius). The jute fibers (4.0 tex) were irradiated by fast neutrons with an energy of 4.44 MeV at different fluences ranging from 2 × 109 to 2 × 1013 n/cm2. An important aspect of neutron irradiation is that the fast neutrons can produce dense ionization at deep levels in the materials. Structural analysis of the raw and irradiated fibers were studied by small‐angle X‐ray scattering (SAXS), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy. Thermal analysis carried out on the raw and irradiated fibers showed that the thermal stability of the fibers decreased after irradiation. The mechanical properties of the jute fibers were found to decrease after irradiation. The SAXS study showed that the average periodicity transverse to the layer decreased after irradiation, which may have been due to the shrinkage of cellulosic particles constituting the fiber. The residual compressive stress developed in the fiber after irradiation resulted in a decrease in crystallite size as supported by our XRD analysis. Observation with SEM did not indicate any change produced in the surface morphology of the fiber due to irradiation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008