bluuebunny/crossref_metadata_2025_split huggingface dataset:
Component D of chicken hemoglobin and the hemoglobin of the embryonic Tammar wallaby (Macropus eugenii) self‐associate upon deoxygenation: Effect on oxygen binding
Authors: Rana Mitra S. , Knapp James E. , Holland Robert A. B. , Riggs Austen F. 
Published: October 2007

AbstractExtensive measurements of oxygen binding by some vertebrate hemoglobins (Hbs) have suggested an unusually high degree of cooperativity with reported Hill coefficients, nH, greater than 4.0. We have reexamined this possibility of “super‐cooperativity” with chicken Hb components A (αA2β2) and D (αD2β2). Prior studies have shown that component D but not A self‐associates to dimers of tetramers upon deoxygenation. This self‐association is reflected in the oxygen equilibrium of Hb D which shows a maximal nH, greater than 4.0 at ∼4 mM heme concentration. In contrast, component A has maximal nH value below 3. The value of the maximal nH for Hb D increases linearly with the fraction of octamer present in the deoxy Hb. We anticipate that deoxygenation‐dependent self‐association will be shown to be a general property of Hb D from birds and reptiles. Neither oxygen equilibria nor sedimentation measurements show any evidence that components A and D interact to form a complex when deoxygenated. We have also reexamined the oxygen equilibria of Hbs of an embryonic marsupial, the wallaby. The equilibria in red cells have been reported to have Hill coefficients as high as 5–6. Although our oxygen equilibrium measurements of solutions of unfractionated wallaby Hb at a concentration of ∼1 mM show no nH values greater than ∼3.0, sedimentation velocity measurements provide clear evidence for deoxygenation‐dependent self‐association. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Susceptibility to thiamethoxam of Musca domestica from Danish livestock farms
Authors: Kristensen Michael , Jespersen Jørgen B 
Published: October 2007

AbstractBACKGROUND: Neonicotinoid baits are currently replacing anticholinesterase baits for control of adult houseflies (Musca domestica L.). Introduction of new insecticides includes evaluation of their cross‐resistance potential, which was assessed for thiamethoxam in field populations from Denmark.RESULTS: In feeding bioassay with a susceptible strain, thiamethoxam LC50 at 72 h was 1.7 µg thiamethoxam g−1 sugar, making it 19‐fold, 11‐fold and threefold more toxic to houseflies than azamethiphos, methomyl and spinosad respectively. The field populations were 6–76‐fold resistant to thiamethoxam. There was no correlation between the toxicities of thiamethoxam and spinosad, dimethoate, methomyl, bioresmethrin or azamethiphos. The toxicity in feeding bioassay at 72 h of imidacloprid in a susceptible strain was 32 µg imidacloprid g−1 sugar at LC50, making it 19‐fold less toxic to houseflies than thiamethoxam. There was a strong significant correlation between the toxicities of thiamethoxam and imidacloprid in field populations.CONCLUSION: Neonicotinoid‐resistant houseflies were present at a detectable and noticeable level before thiamethoxam and imidacloprid were introduced for housefly control in Denmark. The toxicity of thiamethoxam is explained by other parameters than the toxicities of spinosad, dimethoate, methomyl, bioresmethrin or azamethiphos. The cross‐resistance between thiamethoxam and imidacloprid indicates a coincidence of mechanism of the toxicity and resistance in the field populations. Copyright © 2007 Society of Chemical Industry
Involvement of excited triplet state in the photodissociation of cyclobutane
Authors: Lei Yibo , Suo Bingbing , Li Anyang , Dou Yusheng , Wang Yubin , Wen Zhenyi 
Published: October 2007

AbstractThe potential energy curves (PECs) of the ground state and the low‐lying excited states for the photodissociation of cyclobutane have been calculated at the multi‐reference configuration interaction with singlet and doublet excitation (MRCISD) and the multi‐reference second order perturbation theory (MRPT2). Firstly, the PECs are constructed following a reaction path determined by semiclassical dynamics simulation, which suggests that the lowest triplet state of tetramethylene is involved in the photodissociation of cyclobutane. Then, the adiabatic PECs are calculated for the breaking processes of C1C3 and C2C4 bond respectively. The singlet‐triplet PECs' intersections have been found in the two breaking CC bond processes. During the breaking process of the second C2C4 bond, a local minimum has been found on the PEC of the lowest triplet state, which gives us some insight to reinterpret the experimental observed diradical intermediate as being trapped in its triplet state. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
How the System Dynamics Society came to be: a collective memoir
Authors: Andersen David , Morecroft John , Spencer Roberta , Forrester Jay , Karsky Michel , Paulré Bernard , Pugh Jack , Radzicki Michael , Randers Jørgen , Richardson George , Saeed Khalid , Wolstenholme Eric 
Published: October 2007

AbstractIn this paper several of the early workers in the field of system dynamics tell some of the history of the Society itself. Several slightly different versions of this story have been told over the past several years and we thought it would be interesting to involve a broader group in this kind of modified oral history project. The paper is based on a series of separate written recollections that have been posted in full on the web at http://www.systemdynamics.org/history/oral_history.htm. Copyright © 2007 John Wiley & Sons, Ltd.
Application of system dynamics to corporate strategy: an evolution of issues and frameworks
Authors: Weil Henry Birdseye 
Published: October 2007

AbstractI discuss five projects that became important building blocks in the application of system dynamics to corporate strategy. The first captures the tension among conflicting performance objectives and their impact on company performance. The second represents an R&D organization as it responds to changing pressures and direction from management. The third explains the progressive “commoditization” of products and services. The fourth examines the dynamics of innovative industries. The final model focuses on the market impacts of social factors, e.g., trust, fashion, bandwagon effects and network effects. The progression began with classical industrial dynamics models focused on orders, production, and shipments. Each milestone marks greater behavioral richness and complexity. What do we know now that we did not know when the field was founded fifty years ago? The most important lessons concern the critical roles of organizational, social, and psychological factors in important business decisions, competition and the evolution of markets. Copyright © 2007 John Wiley & Sons, Ltd.
Nonlinear dynamic phenomena in the beer model
Authors: Mosekilde Erik , Laugesen Jakob L. 
Published: October 2007

AbstractThe production–distribution system or “beer game” is one of the most well‐known system dynamics models. Notorious for the complex dynamics it produces, the beer game has been used for nearly five decades to illustrate how structure generates behavior and to explore human decision making. Here we present a formal bifurcation analysis to analyse the complex dynamics produced by the model. Consistent with the rules of the game, the model constitutes a piecewise‐linear map with nonlinearities arising from non‐negativity constraints. The bifurcations that occur in piecewise‐linear systems are distinctly different from those observed in smooth systems. We show how the model displays abrupt Hopf and period‐doubling bifurcations, truncated bifurcation cascades, and various border‐collision bifurcations. The latter allow direct transitions from periodic to chaotic dynamics. Bifurcation phenomena in models that use piecewise‐linear functions to represent nonlinearities are likely to show similar qualitative differences from the bifurcations known from smooth systems. Copyright © 2007 John Wiley & Sons, Ltd.
Chronic illness in a complex health economy: the perils and promises of downstream and upstream reforms
Authors: Homer Jack , Hirsch Gary , Milstein Bobby 
Published: October 2007

AbstractChronic illness is the largest cause of death and source of health care costs in developed countries and a growing problem in developing countries. Here we build on past work in system dynamics and present a generic model of chronic illness, its treatment and prevention, applied to the U.S. population. The model explains the rising prevalence of illness and responses to it, including the treatment of complications and management activities designed to reduce complications. We show how progress in treatment and disease management has slowed since 1980 in the U.S., largely due to competition between health care payers and providers, resulting in price inflation and an unstable climate for health care investments. We demonstrate the impact of moving “upstream” by managing known risk factors to prevent illness onset, and moving even further upstream by addressing behaviors and living conditions linked to the initial development of these risk factors. Copyright © 2007 John Wiley & Sons, Ltd.
System dynamics—a personal view of the first fifty years
Authors: Forrester Jay W. 
Published: October 2007

AbstractI present a personal recollection of the history of system dynamics and observations about its present state. The article treats the history in two parts: first, my personal background and how all the threads came together to initiate the field of system dynamics; and second, the historical development of the cornerstone projects that shaped the field. These early works include industrial dynamics, urban dynamics, world dynamics, and the national economic model. The paper continues with an assessment of the present condition of the field. A companion paper (System Dynamics—The Next Fifty Years, also in this issue of System Dynamics Review), highlights challenges for the future. Copyright © 2007 Jay W. Forrester.
A meta‐analysis of national research: Effects of teaching strategies on student achievement in science in the United States
Authors: Schroeder Carolyn M. , Scott Timothy P. , Tolson Homer , Huang Tse‐Yang , Lee Yi‐Hsuan 
Published: October 2007

AbstractThis project consisted of a meta‐analysis of U.S. research published from 1980 to 2004 on the effect of specific science teaching strategies on student achievement. The six phases of the project included study acquisition, study coding, determination of intercoder objectivity, establishing criteria for inclusion of studies, computation of effect sizes for statistical analysis, and conducting the analyses. Studies were required to have been carried out in the United States, been experimental or quasi‐experimental, and must have included effect size or the statistics necessary to calculate effect size. Sixty‐one studies met the criteria for inclusion in the meta‐analysis. The following eight categories of teaching strategies were revealed during analysis of the studies (effect sizes in parentheses): Questioning Strategies (0.74); Manipulation Strategies (0.57); Enhanced Material Strategies (0.29); Assessment Strategies (0.51); Inquiry Strategies (0.65); Enhanced Context Strategies (1.48); Instructional Technology (IT) Strategies (0.48); and Collaborative Learning Strategies (0.95). All these effect sizes were judged to be significant. Regression analysis revealed that internal validity was influenced by Publication Type, Type of Study, and Test Type. External validity was not influenced by Publication Year, Grade Level, Test Content, or Treatment Categories. The major implication of this research is that we have generated empirical evidence supporting the effectiveness of alternative teaching strategies in science. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 44: 1436–1460, 2007
Exploring the factors related to acceptance of evolutionary theory among Turkish preservice biology teachers: Toward a more informative conceptual ecology for biological evolution
Authors: Deniz Hasan , Donnelly Lisa A. , Yilmaz Irfan 
Published: November 2007

AbstractIn this study, using multiple regression analysis, we aimed to explore the factors related to acceptance of evolutionary theory among preservice Turkish biology teachers using conceptual ecology for biological evolution as a theoretical lens. We aimed to determine the extent to which we can account for the variance in acceptance of evolutionary theory by using understanding of evolutionary theory, epistemological beliefs, thinking dispositions, and parents' educational level as independent variables. Preservice biology teachers' thinking dispositions, their understanding of evolutionary theory, and their parents' educational level are positively correlated with acceptance of evolutionary theory. We did not find any significant positive correlation between epistemological beliefs and acceptance of evolution because of low reliability coefficients of subscales of the epistemological beliefs instrument. Together they explained 10.5% of the variance. These results suggest that studying the relationship between acceptance of evolutionary theory and other related factors in a multivariate context is more informative than examining the relationship between acceptance of evolutionary theory and other factors in isolation. Our findings indicate that studying a controversial issue such as acceptance of evolutionary theory in a multivariate fashion, using conceptual ecology as a theoretical lens to interpret the findings, is informative. Our results suggest the inclusion of thinking dispositions in conceptual ecology for biological evolution. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 45: 420–443, 2008
Reproductive and thyroid hormone profiles in captive Western fence lizards (Sceloporus occidentalis) after a period of brumation
Authors: Brasfield Sandra M. , Talent Larry G. , Janz David M. 
Published: November 2007

AbstractSeasonal fluctuation in serum concentrations of sex steroid (testosterone [T] and 17β‐estradiol [E2]) and thyroid (triiodothyronine [T3] and thyroxine [T4]) hormones was determined in captive Western fence lizards (Sceloporus occidentalis). Samples were collected from male and female breeding pairs weekly for a 4‐month period after their emergence from artificial brumation. Circulating levels of E2 corresponded with the expected vitellogenic and ovulatory cycles in females, and surprisingly, E2 in males followed a similar pattern, indicating a possible role in breeding behavior. Serum T was elevated in male lizards for the first 6 weeks after emergence from brumation, possibly related to an increase in the onset of active spermatogenesis. Thyroid hormones showed little cyclical activity throughout the breeding period, with the exception of small increases of T3 at weeks 8 and 16, possibly implying an active role of this hormone with ovulation in females. Overall, these baseline hormone data are not only useful in developing this animal as a laboratory reptile model for assessment of endocrine‐mediated toxicity, but also of value for understanding herpetological endocrinology and for application in the conservation of threatened species. Zoo Biol 27:36–48, 2008. © 2007 Wiley‐Liss, Inc.
Antioxidant Activity of Raisin Extracts in Bulk Oil, Oil in Water Emulsion, and Sunflower Butter Model Systems
Authors: Zhao Bin , Hall Clifford A. 
Published: October 2007

AbstractThe antioxidant activities of the raisin extract (RE) in stripped corn oil, stripped corn oil emulsions, and sunflower butter stored at 60 °C for up to 15 days was evaluated. Peroxide values and hexanal content were measured on a half day, 2 or 3 day basis for the emulsion, sunflower butter, and bulk oil, respectively. The RE had the best antioxidant activity in the bulk oil system. Statistical contrasts indicated the oxidation of bulk corn oil treated with RE was significantly (p < 0.001 and p = 0.044) lower than bulk oil and bulk oil treated with tertiary‐butylhydroquinone (TBHQ), respectively. No differences (p = 0.15) in hexanal concentrations were observed in stored bulk oils treated with RE and TBHQ. However, both these materials inhibited hexanal formation better (p < 0.001) when compared to the control corn oil. In contrast, 200 μg/g TBHQ had better (p = 0.0004) antioxidant activity than 3,000 μg/g RE in the oil in water(o/w) emulsion. No significant differences (p = 0.1637) in hexanal formation were observed in the emulsions treated with RE and TBHQ. However, the data indicated that the RE treated emulsion did undergo more secondary oxidation than the emulsion treated with TBHQ beyond 110 h. The 3,000 μg/g RE had antioxidant activity in sunflower butter, but was less effective than the 200 μg/g TBHQ and a lower RE concentration (200 μg/g). The observations supported the hypothesis that RE has antioxidant activity in the multiple model systems.
Differential effect of sanguinarine, chelerythrine and chelidonine on DNA damage and cell viability in primary mouse spleen cells and mouse leukemic cells
Authors: Kaminskyy Vitaliy , Lin Kah‐Wai , Filyak Yevhen , Stoika Rostyslav 
Published: October 2007

AbstractSanguinarine, chelerythrine and chelidonine are isoquinoline alkaloids derived from the greater celandine. They possess a broad spectrum of pharmacological activities. It has been shown that their anti‐tumor activity is mediated via different mechanisms, which can be promising targets for anti‐cancer therapy. We focused our study on the differential effects of these alkaloids upon cell viability, DNA damage effect and nucleus integrity in mouse primary spleen cells and mouse lymphocytic leukemic cells, L1210. Sanguinarine and chelerythrine produce a dose‐dependent increase in DNA damage and cytotoxicity in both primary mouse spleen cells and L1210 cells. Chelidonine did not show a significant cytotoxicity or damage DNA in both cell types, but completely arrested growth of L1210 cells. Examination of nuclear morphology revealed more cells with apoptotic features upon treatment with chelerythrine and sanguinarine, but not chelidonine. In contrast to primary mouse spleen cells, L1210 cells showed slightly higher sensitivity to sanguinarine and chelerythrine treatment. This suggests that cytotoxic and DNA damaging effects of chelerythrine and sanguinarine are more selective against mouse leukemic cells and primary mouse spleen cells, whereas chelidonine blocks proliferation of L1210 cells. The action of chelidonine on normal and tumor cells requires further investigation.
Family Follies
Authors: POLLARD LISA 
Published: October 2007

“The wife: I bet your friends envy you your domestic happiness!” Reprinted with permission of Mohammed Elchamaa.This cartoon comes from a 1948 edition of the Egyptian periodical Akhir Saʿa. I happened across it in Cairo, as part of some exploratory research into the fate of the female image of the Egyptian nation-state that was so central to the 1919 revolution. In previous inquiries, I had noticed that “lady Egypt” or “mother Egypt” or “Egypt as a woman,” to use historian Beth Baron's expression, lost pride of place in popular periodicals as 1919 gave way to nominal independence and nation building. By the late 1920s, cartoon and caricature space was more frequently dedicated to men engaged in laying the foundations of new political, legal, and educational systems, as well as erecting the buildings that would house them. Throughout the 1930s, political caricatures also frequently lampooned prominent Egyptian men for their behavior in the institutions that they had been active in creating. In the popular press, the reified female figure of the Egyptian nation was all but usurped by the men who built the state (and who seemed determined to keep Egyptian women out of the body politic).
Weakly turbulent laws of wind-wave growth
Authors: BADULIN SERGEI I. , BABANIN ALEXANDER V. , ZAKHAROV VLADIMIR E. , RESIO DONALD 
Published: October 2007

The theory of weak turbulence developed for wind-driven waves in theoretical works and in recent extensive numerical studies concludes that non-dimensional features of self-similar wave growth (i.e. wave energy and characteristic frequency) have to be scaled by internal wave-field properties (fluxes of energy, momentum or wave action) rather than by external attributes (e.g. wind speed) which have been widely adopted since the 1960s. Based on the hypothesis of dominant nonlinear transfer, an asymptotic weakly turbulent relation for the total energy ϵ and a characteristic wave frequency ω* was derived

The self-similarity parameter αss was found in the numerical duration-limited experiments and was shown to be naturally varying in a relatively narrow range, being dependent on the energy growth rate only.In this work, the analytical and numerical conclusions are further verified by means of known field dependencies for wave energy growth and peak frequency downshift. A comprehensive set of more than 20 such dependencies, obtained over almost 50 years of field observations, is analysed. The estimates give αss very close to the numerical values. They demonstrate that the weakly turbulent law has a general value and describes the wave evolution well, apart from the earliest and full wave development stages when nonlinear transfer competes with wave input and dissipation.
Revisiting Batchelor's theory of two-dimensional turbulence
Authors: DRITSCHEL DAVID G. , TRAN CHUONG V. , SCOTT RICHARD K. 
Published: October 2007

Recent mathematical results have shown that a central assumption in the theory of two-dimensional turbulence proposed by Batchelor (Phys. Fluids, vol. 12, 1969, p. 233) is false. That theory, which predicts a χ2/3k−1 enstrophy spectrum in the inertial range of freely-decaying turbulence, and which has evidently been successful in describing certain aspects of numerical simulations at high Reynolds numbers Re, assumes that there is a finite, non-zero enstrophy dissipation χ in the limit of infinite Re. This, however, is not true for flows having finite vorticity. The enstrophy dissipation in fact vanishes.We revisit Batchelor's theory and propose a simple modification of it to ensure vanishing χ in the limit Re → ∞. Our proposal is supported by high Reynolds number simulations which confirm that χ decays like 1/ln Re, and which, following the time of peak enstrophy dissipation, exhibit enstrophy spectra containing an increasing proportion of the total enstrophy 〈ω2〉/2 in the inertial range as Re increases. Together with the mathematical analysis of vanishing χ, these observations motivate a straightforward and, indeed, alarmingly simple modification of Batchelor's theory: just replace Batchelor's enstrophy spectrum χ2/3k−1 with 〈ω2〉 k−1 (ln Re)−1).
Targeting the cannabinoid CB2 receptor: modelling and structural determinants of CB2 selective ligands
Authors: Poso A , Huffman J W 
Published: November 2007

Recent developments indicate that CB2 receptor ligands have the potential to become therapeutically important. To explore this potential, it is necessary to develop compounds with high affinity for the CB2 receptor and little affinity for the CB1 receptor. This review will discuss structure‐activity relations at both receptors for classical cannabinoids and cannabimimetic indoles. Examples of CB2 selective ligands from both classes of compounds are presented and the structural features leading to selectivity are described. Two approaches, receptor mutations and molecular modelling, have been employed to investigate the interaction of ligands with both cannabinoid receptors. These results obtained from these techniques are discussed.British Journal of Pharmacology(2008)153, 335–346; doi:10.1038/sj.bjp.0707567; published online 5 November 2007