bluuebunny/crossref_metadata_2025 huggingface dataset:
Bewertung der Sicherheitsanforderungen von Temperatureinwirkungen auf Brücken
Authors: Mangerig Ingbert , Lichte Ulf , Beucher Stefan
Published: March 2010

Der Aufsatz beschäftigt sich mit Grundlagenuntersuchungen zur Festlegung eines Teilsicherheitsbeiwerts für Temperatureinwirkungen auf Brücken. Zur zuverlässigen Ableitung der angestrebten Aussagen wurde über numerische Langzeitsimulationen die erforderliche Datenbasis geschaffen. Den Berechnungen lagen typische Brückenquerschnitte in Stahl‐, Verbund‐ und Betonbauweise zugrunde. Zur Darstellung repräsentativer Wetterszenarien standen kontinuierliche Wetterdaten eines Zeitraums von drei Jahren zur Verfügung. Die abzuleitenden Grenzwerte wurden unter der Vorgabe einer mittleren Wiederkehrperiode von 50 Jahren über Extremwertbetrachtungen bestimmt. Durch Vergleiche mit den im DIN‐Fachbericht 101 angegebenen charakteristischen Werten der Temperatureinwirkungen können analog zur bestehenden Praxis die zu erwartenden Extremwerte in das semiprobabilistische Sicherheitskonzept integriert werden. Mit dieser Vorgehensweise konnte der Zielvorgabe, das bewährte Konzept der Berechnung von Temperatureinwirkungen unverändert zu belassen und die Streubreiten mit einem Sicherheitsabstand zu berücksichtigen, entsprochen werden.

Validation of the safety coefficients for thermal load on bridges. This paper covers basic analysis for the determination of partial safety coefficients for thermal loads on bridges. Long‐term numerical simulations were performed to achieve an appropriate database for reliable predictions. The calculations were based on typical bridge cross‐sections in steel, composite and concrete constructions and representative weather scenarios. The weather data was provided for a continuous period of three years. The obtained limit values were determined on the basis of a fifty years recurrence by the use of limit value analysis. Considering the characteristic values of DIN‐Fachbericht 101 for thermal load the estimated limit values were integrated analog to practical use into the semi‐probabilistic safety concept. Therefore it was possible to keep the well established concept of calculating the thermal load unchanged, while the scatter range was covered by a safety margin.
Eisenbahnbrücken in Stahlverbundbauweise
Authors: Schmitt Victor , Seidl Günter
Published: March 2010

Eisenbahnbrücken in Verbundbaubauweise spielen eine sehr unterschiedliche Rolle in den einzelnen Ländern Europas, und die Wirtschaftlichkeit ihres Lebenszyklus' wird jeweils ganz verschieden bewertet. Auch in der konstruktiven Durchbildung der Brücken zeigen sich neue Ansätze. Anhand von Verbundbauwerken, die in Frankreich und in Deutschland in der letzten Zeit gebaut wurden, werden die wichtigsten Einsatzgebiete beschrieben und die Unterschiede in der Konstruktion deutlich.

Railway bridges using steel‐concrete composite structures. Railway bridges using steel‐concrete composite cross‐sections play a different role in the countries of Europe. The assessment of the economic efficiency during a life cycle differs considerably. The design of composite bridges reveals innovative approaches. By means of composite construction which is in use in France and in Germany in recent times, the range of application is figured out and the differences in construction become visible.
Forschungsschwerpunkte im Fachverband Konstruktiver Glasbau
Authors: Klimke Herbert , Wellershoff Frank
Published: March 2010

Der Fachverband Konstruktiver Glasbau, kurz FKG, setzt sich zusammen aus Produktions‐ und Veredlungsbetrieben, Ingenieurbüros und Forschungsstellen die den technischen Fragestellungen des Glasbaus gemeinsam auf den Grund gehen möchten. Die übergeordneten Zielsetzungen des FKG sind:

– Grundlagenforschung, auf deren Basis mehrere Mitgliedsfirmen ihre Produkte eigenständig weiterentwickeln können, als Beispiele seien hier die qualitätssichernden Maßnahmen bei der Herstellung von thermisch teilvorgespannten Gläsern genannt

– Bemessungs‐ und Nachweismethoden erarbeiten und in neue Normen umsetzen, als Beispiel sei hier die Verbundwirkung von Verbundglas unter Wind‐ oder Schneelasten genannt

Um die Kosten dieser anwendungsorientierten Forschung möglichst gerecht zu verteilen, können die Mitglieder ihren Mitgliedsbeitrag durch die Mitarbeit in einzelnen Arbeitsgruppen reduzieren. Hierdurch wird ein hohes Maß an Umsetzbarkeit der Ergebnisse sichergestellt. In diesem Beitrag wird der Stand der Arbeiten des FKG in aktuellen Forschungsschwerpunkten des konstruktiven Glasbaus zusammengefasst.

Research priorities of the German Federation for Structural Glass in Building. The German Federation for Structural Glass in Building (Fachverband Konstruktiver Glasbau, FKG) is a joint venture of companies, which produce or refine glass, of engineering offices and research institutes. The common idea of this group is to increase the knowledge for structural glass in the fields of production, engineering and application. The main goals of the federation are:

– Basic research which enables numerous companies in the federation to further develop their products, e.g. the quality requirements for the production of heat strengthened glass

– Development of design methods and implementation into national codes, e.g. the design of point supported glass or the shear interaction in laminated glass under wind‐ or snow loads

To split the costs for this market driven research as fair as possible, those companies that actively participate in the working groups can reduce their membership fee. This motivates the companies to participate and guaranties that the research results are useful for daily practice. This paper summarises the state of work in the federation FKG.
Flexural ductility and deformability of concrete beams incorporating high‐performance materials
Authors: Ho J. C. M. , Lam J. Y. K. , Kwan A. K. H.
Published: March 2010

High‐performance materials, such as high‐strength concrete (HSC) and high‐strength steel (HSS), are often adopted in tall buildings to reduce member size and save space. The use of HSC and/or HSS can significantly increase the flexural strength of concrete members but may also adversely affect the flexural ductility and deformability. Herein, the pros and cons of using HSC and HSS in concrete beams are investigated in terms of the limits of flexural strength, ductility and deformability that can be simultaneously achieved using nonlinear moment‐curvature analysis with stress‐path dependence of the reinforcement taken into account. The results reveal that the use of HSC or both HSC and HSS in concrete beams can at the same strength increase the ductility and deformability, or increase the strength without depleting the ductility and deformability. However, the use of HSS has no such benefit, albeit it can reduce the steel area required. Copyright © 2010 John Wiley & Sons, Ltd.
Rehabilitation of a high‐rise coupled shear wall system in a 56‐storey residential reinforced concrete building (Tehran Tower), based on nonlinear dynamic time‐history analyses
Authors: Esmaili Omid , Epackachi Siamak , Mirghaderi Rasoul , Behbahani Ali Asghar Taheri , Vahdani Shahram
Published: March 2010

Tehran Tower is a 56‐storey reinforced concrete tall building consisting of three wings with identical plan dimensions each approximately 48 m by 22 m. The three wings are at 120° from each other and have no expansions/seismic joints. This paper contains the consideration of the rehabilitation of the Tehran Tower based on the findings of an exhaustive investigation of the nonlinear performance evaluation efforts. It has tried to show the procedure followed, methodologies utilized and the results obtained for life‐safety (LS) and collapse‐prevention (CP) evaluations of the building. Moreover, the weak zones of the structure due to analysis results are introduced and appropriate retrofit technique for satisfaction related to LS and CP criteria is presented. In this project, to improve the local behaviour of coupling panels that are regularly located in spine walls, and definitely have been recognized as the most vulnerable structural elements, making use of steel plates that are connected to concrete members by chemical anchors has been used as the best rehabilitation method for this case. Therefore, in the final section, the professional practical method utilized to perform the aforementioned project is explained. Copyright © 2010 John Wiley & Sons, Ltd.
Evaluation of creep and shrinkage effects in composite tall buildings
Authors: Chowdhary Peeyush , Sharma Ravi K.
Published: March 2010

In a composite tall building, adjacent vertical members undergo differential time‐dependent deformations due to creep and shrinkage. Highly elaborate, complex and requiring large computational effort procedure, utilizing stress transfer method, age‐adjusted effective modulus method (AEMM) is available to evaluate creep and shrinkage effects in a composite building.

Recently, a simple procedure and requiring lesser computational effort, utilizing AEMM has been presented for concrete and composite buildings. Studies comparing deflections and axial forces in reinforced concrete frames with those obtained from the procedure available in literature (using stress transfer method, RCM) have been reported.

In this paper, suitability of the above procedures for evaluation of creep and shrinkage effects in composite buildings has been demonstrated. Studies are reported for typical creep shrinkage parameters. It is shown that the error to determine axial forces from AP(AEMM) is small for composite frame–shear wall systems with very low beam stiffness (Ib = Ic/100). Use of CP(AEMM) is warranted for the frame–shear wall systems even with low beam stiffness (Ib = Ic/20). Copyright © 2010 John Wiley & Sons, Ltd.
Simpson's paradox
Authors: Alin Aylin
Published: March 2010

Simpson's paradox occurs when an observed association between two variables is reversed after considering the third variable. Having two different conclusions makes this phenomenon paradoxical. In this article, it will be shown that the source of this paradox is the interactions between the third variable and any of the other two variables. There will also be a section about which association should be trusted. Copyright © 2010 John Wiley & Sons, Inc.

This article is categorized under:

Statistical Models > Classification Models
B‐splines
Authors: Gillies Duncan
Published: March 2010

B‐splines are a family of smooth curves that can be constructed to interpolate or approximate a set of control points. They are used extensively for curve and surface design in engineering and media applications. Their popularity comes from the fact that they offer a simple and intuitive means of adjusting the shape of a curve or surface interactively. Any point on a B‐spline curve or surface is defined as a local blend of the control points. The most widely used blending functions are cubic. Higher order blending makes the surface smoother and consequently less detailled. The normal formulation of the B‐spline blend is in a parametric space where the control points are equally distributed. Non uniform splines use an irregular distribution of the control points to create special effects, such as discontinuities in the curve or surface. Rational splines provide a further means of user interaction by weighting each point such that the curve is pulled more strongly towards the higher weights. Copyright © 2010 John Wiley & Sons, Inc.

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Density Estimation
Multicollinearity
Authors: Alin Aylin
Published: March 2010

Multicollinearity refers to the linear relation among two or more variables. It is a data problem which may cause serious difficulty with the reliability of the estimates of the model parameters. In this article, multicollinearity among the explanatory variables in the multiple linear regression model is considered. Its effects on the linear regression model and some multicollinearity diagnostics for this model are presented. Copyright © 2010 John Wiley & Sons, Inc.

This article is categorized under:

Statistical Models > Linear Models

Statistical Models > Multivariate Models
WIREs is a WINNER
Authors: Wegman Edward J. , Said Yasmin H. , Scott David W.
Published: March 2010

This article is categorized under:

Applications of Computational Statistics > Organizations and Publications
Fixation of Metallo Nitrile Ylides and Metallo Nitrile Imines as Ligands in Transition Metal Complexes [1]
Authors: Völkl Alfons , Achatz Dagobert , Schoder Friedrich , Zinner Gerhard , Stolzenberg Heribert , Beck Wolfgang , Fehlhammer Wolf Peter
Published: March 2010

1,3‐Dipoles of the type metallo nitrile ylide and metallo nitrile imine were prepared by mono‐α‐deprotonation of CH‐acidic {[W(CO)5CHCH2PPh3]PF6, M(CO)5CNCH2CO2R (M = Cr, W; R = Me, Et), [Pt(Cl)(CNCH2CO2Et)(PPh3)2]BF4} and NH‐acidic isocyanide complexes (Cr(CO)5CNNH2) and were stabilized by coordination to a second transition metal complex fragment {Cr(CO)5, [M(CO)5]+ (M = Mn, Re), [FeCp(CO)2]+, [Pt(Cl)(PR3)2]+ (R = Et, Ph)}. All dinuclear products 1–7, 10, and 11 are neutral species except [(Ph3P)2(Cl)Pt{μ2‐CNCH(CO2Et)}Pt(Cl)(PPh3)2]BF4 (8). Complex (OC)5W{μ2‐CNCH(CO2Et)}Pt(Cl)(PEt3)2 (5b) was characterized by X‐ray diffraction. Twofold deprotonation/platination to give (OC)5Cr{μ3‐CNC(Ph)}[Pt(Cl)(PPh3)2]2 (9) was achieved in the case of Cr(CO)5CNCH2Ph.
Do pollen diets vary among adjacent bumble bee colonies?
Authors: Munidasa Dulee Tamirei , Toquenaga Yukihiko
Published: March 2010

Central‐place foragers, such as bumble bees, are often constrained by their location when collecting resources to provide their young. We compared the resource use (pollen diets) among seven feral colonies of Bombus ardens located in an area of 2.5 × 2.5 km2. Because this area was likely to be within their maximum foraging distance, most floral resources could have been accessible to all colonies alike. Similarities in pollen diets among these colonies may suggest that the surrounding resources determine resources use, while deviations from this could reveal other factors that affect resources use among colonies. We examined if colonies showed similarities in pollen diets and if colonies do differ in pollen diets, we investigated whether factors, such as establishment year, colony size, and location, affected the colony pollen diets. We found that while the choices of floral resources were similar, the proportional use of the floral resources were significantly different, suggesting that the surrounding resources do not solely determine resource use among colonies. Further analyses showed that the dissimilarity of pollen diets between two colonies increased as spatial distance decreased, as the temporal distances increased, and as the difference in colony size increased. We found that other than differences in annual variances of resources distribution, colony size was the prominent factor that affected the resource use of our seven colonies. We propose that colony‐size‐dependent work‐force differences and other unidentified colony‐size‐related factors could have significant effects on floral use among colonies overlapping spatially and temporally.
The exploratory analysis of autocorrelation in animal‐movement studies
Authors: Dray Stéphane , Royer‐Carenzi Manuela , Calenge Clément
Published: March 2010

Studies of animal movements have been popularized for many large and shy species by the increasing use of radio telemetry methods (VHF and GPS technologies). Data are collected with high sampling frequency, and consist of successive observations of the position of an individual animal. The statistical analysis of such data poses several problems due to the lack of independence of successive observations. However, the statistical description of the temporal autocorrelation between successive steps is rarely performed by ecologists studying the patterns of animals movements. The aim of this paper is to warn ecologists against the consequences of failing to consider this aspect. We discuss the various issues related to analyzing autocorrelated data, and show how the exploratory analysis of autocorrelation can both reveal important biological insights and help to improve the accuracy of movement models. We suggest some tools that can be used to measure, test, and adjust for temporal autocorrelation. A short ecological illustration is presented.
Dietary starch source influences in growing goats: the intestinal losses of endogenous nitrogen and amino acids
Authors: Zhou Chuanshe , Tan Zhiliang , Pan Yafei , Liu Shimin , Tang Shaoxun , Sun Zhihong , Han Xuefeng , Wang Min
Published: March 2010

Four goats (20 (SD2·5) kg) fitted with ruminal, duodenal and ileal cannulae were used in a 4 × 4 Latin square design to estimate the effects of a dietary starch source on the duodenal and ileal flows of endogenous N (EN) and endogenous amino acids (EAA) in growing goats. Goats were fed total mixed rations containing four starch sources (mainly from maize (MR), wheat (WR), paddy (PR) and sorghum (SR) treatments). There were no significant (P>0·05) effects of the dietary starch source on the intestinal flows of EN and EAA. The duodenal flows of EN were 2·40, 2·39, 2·18 and 1·56 g/d for the MR, WR, PR and SR treatments, respectively, as determined by the difference method, and the duodenal flows of EAA were 10·76, 11·29, 10·95 and 10·96 g/d by estimation with the amino acid profile method. The flows of EN and EAA at the ileum were 1·17, 1·12, 1·01, 0·70 and 4·87, 4·95, 4·94, 4·99 g/d, respectively, as estimated by the water-soluble method. The average intestinal reabsorption of EN and EAA was 57·5 %, and the endogenous Leu by the MR treatment was significantly (P < 0·05) lower than that of the other three treatments. The present results indicate that losses of endogenous protein in the intestine were not affected by the dietary starch source.
Body mass index and the risk of infections in institutionalised geriatric patients
Authors: Dorner Thomas E. , Schwarz Franz , Kranz Alexander , Freidl Wolfgang , Rieder Anita , Gisinger Christoph
Published: March 2010

The objective was to examine the effect of BMI on the incidence of various infectious diseases in institutionalised, geriatric subjects. In a retrospective cohort study we analysed medical records of 619 patients aged 75 years and older (mean age 87·6 (sd 6·4) years) who were treated in a geriatric hospital in Vienna, Austria. The total incidence rate of infection in this population was 0·80 per person-year. The most frequent infections were urinary tract infections (0·30 per person-year), followed by infections of the lower respiratory tract (0·19 per person-year), diarrhoea (0·12 per person-year) and other infections (0·20 per person-year). Incidence risk ratios were obtained by a multiplicative Poisson regression model. There was a J-shaped curve in the incidence of infections recorded by BMI with a nadir at 27–28 kg/m2. Compared with the reference group with a BMI of 24–27·9 kg/m2, subjects with a lower BMI had a higher incidence rate of infections. The incidence risk ratios, adjusted for sex, age and chronic diseases, were 1·62 (95 % CI 1·21, 2·17) for those with a BMI of < 20 kg/m2 and 1·84 (95 % CI 1·40, 2·42) for those with a BMI of 20–23·9 kg/m2. However, also patients with a BMI of 28 kg/m2 and above had a higher incidence rate of infections, with an incidence risk ratio of 1·54 (95 % CI 1·07, 2·22). These results show that both underweight and obesity are associated with a higher risk of infections in institutionalised geriatric patients.
Effect of glycomacropeptide fractions on cholecystokinin and food intake
Authors: Keogh Jennifer B. , Woonton Brad W. , Taylor Cheryl M. , Janakievski Filip , Desilva Kirthi , Clifton Peter M.
Published: March 2010

Glycomacropeptide (GMP) is the hydrophilic 64-amino acid C-terminal glycopeptide released into cheese whey when κ-casein is cleaved by chymosin. GMP exists as a mixture of different glycoforms due to the carbohydrates sialic acid (N-acetylneuraminic acid, NeuNAc), galactose (Gal), galactosamine and glucosamine attached by O-glycosidic linkages. GMP reportedly stimulates the release of cholecystokinin (CCK), which may promote satiety. The objectives of the present study were to manufacture three glycoforms of GMP, minimally glycosylated GMP (3·5 (sd 0·1) % NeuNAc and 1·5 (sd 0·1) % Gal), glycosylated GMP (12·0 (sd 0·3) % NeuNAc and 4·2 (sd 0·2) % Gal) and a GMP-depleted whey protein concentrate, and to assess the effects of these fractions relative to glucose on CCK, subjective measures of satiety and food intake. In a randomised double-blind acute study, twenty overweight/obese males (56·9 (sd 7·2) years, 97·4 (sd 8·1) kg, 31·5 (sd 3·0) kg/m2) were recruited to consume four 50 g preloads (two GMP preparations, GMP-depleted whey and glucose) containing 895 kJ. Blood samples and subjective measures of satiety were collected before and at 15, 30, 60, 90, 120 and 180 min after the consumption of preload, and CCK levels were measured. A lunchtime meal of hot food was provided from which subjects ate ad libitum until satisfied. Energy and nutrient intakes from the food consumed were calculated. There was no significant difference in CCK levels, subjective measures of satiety or food intake between treatments at the given preload level. These results suggest that the protein fractions at the dose employed do not influence satiety, CCK levels or energy intake at a subsequent meal.
INTEGRATION OF AQUACULTURE AND ARID LANDS AGRICULTURE FOR WATER REUSE AND REDUCED FERTILIZER DEPENDENCY
Authors: STEVENSON KALB T. , FITZSIMMONS KEVIN M. , CLAY PATRICK A. , ALESSA LILIAN , KLISKEY ANDREW
Published: March 2010

Field irrigation is costly in arid regions, and over-fertilization of farmland can lead to high groundwater nitrate levels and significant environmental challenges. Integrative aquaculture and agriculture (IAA) systems allow the reuse of water and nutrients to offset production costs while promoting greater sustainability. The aim of this study was to test the effectiveness of an IAA system using treatments formed from one water source, groundwater (GRND) or fish pond effluent (EFF), and one chemical fertilizer regime, eliminated (ELIM) or historical (HIST). Treatments were applied to field plots of barley or cotton. There were typically positive effects of EFF applications on crop growth and yield relative to GRND applications under identical fertilizer regimes. However, GRND-HIST almost always outperformed EFF-ELIM, suggesting that substituting effluent irrigations for a historical fertilization regime without pond biosolid or reduced fertilizer applications could be detrimental to crop production.
COMPARATIVE EFFECTIVENESS OF UREA N, POULTRY MANURE AND THEIR COMBINATION IN CHANGING SOIL PROPERTIES AND MAIZE PRODUCTIVITY UNDER RAINFED CONDITIONS IN NORTHEAST PAKISTAN
Authors: ABBASI M. KALEEM , KHALIQ ABDUL , SHAFIQ M , KAZMI MUSHTAQ , ALI IMRAN
Published: March 2010

A field experiment was conducted to evaluate the comparative effectiveness of poultry manure, urea N and the integrated use of both in changing soil properties, nutrient uptake, yield and yield attributes of maize grown at Rawalakot, Azad Jammu and Kashmir, Pakistan. Treatments include control without any amendment (N0); urea N (UN) = 120 kg N ha−1(N120U); UN = 150 kg N ha−1(N150U); poultry manure (PM) = 120 kg N ha−1(N120PM); PM = 150 kg N ha−1(N150PM); UN = 90 kg N ha−1+ PM = 30 kg N ha−1(N90U+30PM); UN = 60 kg N ha−1+ PM = 60 kg N ha−1(N60U+60PM); UN = 30 kg N ha−1+ PM = 90 kg N ha−1(N30U+90PM). N fertilization from different sources and combinations increased dry matter yield from 5206 kg ha−1in the control to 5605–5783 kg ha−1and grain yield increased from 1911 kg ha−1to 2065–3763 kg ha−1. Application of the highest rate of urea N recorded the highest grain yields of 3763 kg ha−1, double the control. The proportional increase for N90U+30PMand N60U+60PMwas 85 and 83% while PM alone gave lower yields (41 and 44%) than the respective urea N treatments. Integrated use of urea + PM proved superior to other treatments in enhancing the uptake of N, P and K in plants. Averaged across two years, uptake of N, P and K in N90U+30PMand N60U+60PMwas 88 and 85, 16.5 and 17.5, and 48.5 and 53.5 kg ha−1, respectively compared to 52.5, 11.5 and 33.5 kg ha−1in the control. Nitrogen use efficiency (NUE) varied from 29% in PM treatments to 30–39% in combined treatments while NUE of 40% was recorded for urea N treatments. Application of PM lowered soil bulk density from 1.19 t m−3in the control to 1.10 and 1.05 t m−3in N120PMand N150U, enhanced pH from 7.39 to 7.65 and 7.78 and increased soil organic matter (22 and 32%), total N (21 and 26%), available P (44 and 55%) and available K (10 and 15%) compared with the control. Economic analysis suggested the use of 50% recommended mineral N (60 kg N ha−1) with PM saves the mineral N fertilizer by almost 50% compared to a system with only mineral N application. In addition, increase in N efficiency, plant nutrition and soil fertility associated with combined treatment would help to minimize the use of high cost synthetic mineral fertilizers and represents an environmentally and agronomically sound management strategy.
Discussion of ‘Classification of fault breccias and related fault rocks’, by Woodcock & Mort: the particular problem of pseudotachylyte
Authors: Magloughlin Jerry F. , Woodcock Nigel H. , Mort Kate
Published: March 2010

J. F. Magloughlin comments: I would like to compliment Woodcock & Mort on an important attempt to bring more order to the complex and under-attended world of fault rock classification. The authors aptly point out several of the persistent difficulties in fault rock terminology, such as the original cohesive-versus-incohesive dichotomy in Sibson's (1977) classification, and they appropriately attempt to create a more nongenetic classification scheme.
Carneades and the Conceit of Rome: Transhistorical Approaches to Imperialism
Authors: FITZPATRICK MATTHEW P.
Published: March 2010

In a recent contribution to Greece & Rome, Thomas Harrison illustrated how the conceit of the United States as the ‘New Rome’ colours our knowledge of both the ancient world and our own. His deceptively light-hearted approach and examples illustrated that the transhistorical approach is certainly one that can be used for fun; however, at its core, the article poses a much more serious question – can the transhistorical approach to imperialism be used for profit? Or, as Harrison posed the question, ‘Can an understanding of ancient imperialisms cast light on contemporary experience?’ Acutely, Harrison points to the symbiosis between interpretations of the past and the present, illustrating the abundance of what might be termed ‘palimpsestic’ readings of modern empires, which are generated by writing through the history of past empires.
Cupid Grows Up
Authors: MORWOOD JAMES
Published: March 2010

The Cupid and Psyche episode in the Metamorphoses of Apuleius is rightly viewed as an escape from the novel's ‘real world’. But that does not of course prevent it from saying serious things about the nature of love and the psychology of the lovers. My aim in this article is to argue that the Cupid who removes Psyche to an earthly paradise (5.1–2.2) is just as much in need of an emotional education as she is. Indeed, initially Psyche could well have been better off with ‘the lowest of mankind’ with whom Venus had instructed him to ensnare her (4.31.3). For her, Cupid may in fact prove at the outset to be the malum (evil) of Apollo's sinister prophecy (4.33.1).
Addendum: The Religious Roles of Children in the Provinces
Authors: MANTLE INGA C.
Published: March 2010

In my previous article, ‘The Roles of Children in Roman Religion’, it was shown, from literary and visual evidence, that children of both sexes played a part in religious cult in choirs and groups, as assistants to priests and other sacrificants, at weddings and in private rites. Most of the evidence cited came from Rome and Italy, as indeed the title implies. Since writing it, however, I have been collecting Latin epitaphs to children throughout the provinces of the Roman empire, and in the course of this study I have come across a small amount of evidence for children in religious roles. It is worth considering whether such children, along with those represented visually, were participating in what might be called offi cial Roman religion or whether they were to some extent involved in their own local cults.
The Uneven Rise of American Public Schools to 1850
Authors: Go Sun , Lindert Peter
Published: March 2010

Three factors help to explain why school enrollments in the Northern United States were higher than those in the South and in most of Europe by 1850. One was affordability: the northern schools had lower direct costs relative to income. The second was the greater autonomy of local governments. The third was the greater diffusion of voting power among the citizenry in much of the North, especially in rural communities. The distribution of local political voice appears to be a robust predictor of tax support and enrollments, both within and between regions. Extra local voice raised tax support without crowding out private support for education.
Characterization of the interactions of two unequal co-rotating vortices
Authors: BRANDT LAURA K. , NOMURA KEIKO K.
Published: March 2010

The interactions and merging of two unequal co-rotating vortices in a viscous fluid are investigated. Two-dimensional numerical simulations of initially equal-sized vortices with differing relative strengths are performed. In the case of equal-strength vortices, i.e. symmetric vortex pairs (Brandt & Nomura, J. Fluid Mech., vol. 592, 2007, pp. 413–446), the mutually induced strain deforms and tilts the vortices, which leads to a core detrainment process. The weakened vortices are mutually entrained and rapidly move towards each other as they intertwine and destruct. The flow thereby develops into a single compound vortex. With unequal strengths, i.e. asymmetric pairs, the disparity of the vortices alters the interaction. Merger may result from reciprocal but unequal entrainment, which yields a compound vortex; however other outcomes are possible. The various interactions are classified based on the relative timing of core detrainment and core destruction of the vortices. Through scaling analysis and simulation results, a critical strain rate parameter which characterizes the establishment of core detrainment is identified and determined. The onset of merging is associated with the achievement of the critical strain rate by ‘both’ vortices, and a merging criterion is thereby developed. In the case of symmetric pairs, the critical strain rate parameter is shown to be related to the critical aspect ratio. In contrast with symmetric merger, which is in essence a flow transformation, asymmetric merger may result in the domination of the stronger vortex because of the unequal deformation rates. If the disparity of the vortex strengths is sufficiently large, the critical strain rate is not attained by the stronger vortex before destruction of the weaker vortex, and the vortices do not merge.
Localized edge states nucleate turbulence in extended plane Couette cells
Authors: SCHNEIDER TOBIAS M. , MARINC DANIEL , ECKHARDT BRUNO
Published: March 2010

We study the turbulence transition of plane Couette flow in large domains where localized perturbations are observed to generate growing turbulent spots. Extending previous studies on the boundary between laminar and turbulent dynamics we determine invariant structures intermediate between laminar and turbulent flow. In wide but short domains we find states that are localized in spanwise direction, and in wide and long domains the states are also localized in downstream direction. These localized states act as critical nuclei for the transition to turbulence in spatially extended domains.
A ‘receptive’ boundary layer
Authors: BOTTARO ALESSANDRO
Published: March 2010

Receptivity is the process which describes how environmental disturbances (such as gusts, acoustic waves or wall roughness) are filtered by a boundary layer and turned into downstream-growing waves. It is closely related to the identification of initial conditions for the disturbances and requires knowledge of the characteristics of the specific external forcing field. Without such a knowledge, it makes sense to focus on worst case scenarios and search for those initial states which maximize the disturbance amplitude at a given downstream position, and hence to identify upper bounds on growth rates, which will be useful in predicting the transition to turbulence. This philosophical approach has been taken by Tempelmann, Hanifi & Henningson (J. Fluid Mech., 2010, vol. 646, pp. 5–37) in a remarkably complete parametric study of ‘optimal disturbances’ for a model of the flow over a swept wing; they pinpoint the crucial importance both of the spatial variation of the flow and of non-modal disturbances, even when the flow is ‘supercritical’ and hence subject to classical ‘normal mode’ instabilities.
Life on the Margins: (Ex) Buccaneers and Spanish Subjects on the Campeche Logwood Periphery, 1660-1716
Authors: Cromwell Jesse
Published: March 2010

In 1675, William Dampier set sail from Jamaica for the Bay of Campeche on Mexico's Yucatán coast to trade for logwood. Dampier, who would later become famous as a naturalist, a buccaneer, and one of the foremost chroniclers of the Golden Age of English buccaneering, recorded his experiences over the course of a year spent in English logwood communities near this Spanish settlement. The author's account gives a fascinating portrayal of a society beyond the margins of imperial control. In Laguna de Términos, an inlet just west of the town of Campeche (in Mexico's Yucatán Peninsula), English sailors cut logwood, a popular dyestuff used in Europe for red, purple, and black clothing dyes and ink, that grew throughout the swampy tropical lowlands of the area. They traded their harvest with merchants who would ship it to ports as far away as Boston, London, and Amsterdam. Seeking an independent life separate from the arbitrary power of shipboard hierarchy, the loggers lived communally. They worked, hunted, and drank on their own schedule.
European Maritime Violence and Territorial States in Early Modern Asia, 1600-1650
Authors: Clulow Adam
Published: March 2010

The European overseas enterprises that began to push into Asian waters in the sixteenth and seventeenth centuries were maritime organisations geared towards commerce and seaborne warfare. As such, they looked very different from the powerful territorial states like Mughal India that traditionally dominated early modern Asia, and they were able to create a new kind of empire consisting of a network of fortified ports and trading centres connected by long sea routes. The construction of these empires was initially driven and subsequently sustained by maritime technology. To borrow Carlo Cipolla's words, guns, sails, and empire were always bound tightly together in this period. European vessels held a significant advantage over local shipping; neither the wealthiest groups of merchants nor the most formidable Asian states were in a position to field maritime forces that could challenge them on the open ocean. In virtually every encounter at sea, ships from Europe were able to inflict overwhelming defeats on the fleets assembled to oppose them. Since it represented their most significant advantage, Europeans made frequent use of maritime violence: against competing merchant groups (in order to disrupt commercial networks and to gain a dominant position), and against Asian states (to pry open port cities and improve trading conditions). This article explores the role played by maritime violence in the relationship between European overseas enterprises and two powerful territorial states, Mughal India (1526-1757) and Tokugawa Japan (1600-1868), in the first half of the seventeenth century.
A Worthwhile Possession: A Reading of Women's Valuation of Slaveholding in the 1875 Gold Coast Ladies' Anti-abolition Petition
Authors: Adu-Boahen Kwabena
Published: March 2010

In late 1874, the Colonial Government of the Gold Coast passed an abolition measure which was designed to end slavery, all other forms of compulsory labour, and slave trading in the colony. The measure took the form of two laws: the Gold Coast Slave-Dealing Abolition Ordinance (1874) and the Gold Coast Emancipation Ordinance (1874). The Gold Coast Legislative Council passed the laws on 17 December 1874 and they received the assent of the Governor on 28 December. On 30 December 1874, the measure was proclaimed. The first of the ordinances absolutely and immediately outlawed the importation of slaves into the Gold Coast, and abolished slave dealing and pawning. The other ordinance provided for the emancipation of slaves by abolishing the legal status of slavery and empowering slaves to leave their owners at will.
Observing the Biofilm Matrix ofStaphylococcus epidermidisATCC 35984 Grown Using the CDC Biofilm Reactor
Authors: Williams Dustin L. , Bloebaum Roy D.
Published: March 2010

Bacteria flourish in nearly every environment on earth. Contributing to their ability to grow in many esoteric locations is their development into a biofilm structure. In an effort to more accurately model the growth environment of biofilms in nature, a Center for Disease Control and Prevention (CDC) biofilm reactor has been developed that mimics nature-like shear forces and renewable nutrient sources. To date, there has been no confirmation by scanning electron microscopy (SEM) that mature biofilms develop on a surface when grown using the CDC biofilm reactor. Three different SEM methods were used to collect images ofStaphylococcus epidermidisATCC 35984 that was to be grown using the CDC biofilm reactor. In addition, two different fixative techniques were used in each of the imaging methods. Results indicated that after 48 hours of growth in the reactor,S. epidermidisATCC 35984 does produce a significant network of matrix components and 3D mushroom- or pillar-like structures with signs of water channel development. In conclusion,S. epidermidisATCC 35984 grown using the CDC biofilm reactor does appear to display signs of mature biofilm development. These results could be important for studies wherein mature biofilms are needed forin vitroand/orin vivoapplications.
Judging Correlation from Scatterplots and Parallel Coordinate Plots
Authors: Li Jing , Martens Jean-Bernard , van Wijk Jarke J
Published: March 2010

Scatterplots and parallel coordinate plots (PCPs) that can both be used to assess correlation visually. In this paper, we compare these two visualization methods in a controlled user experiment. More specifically, 25 participants were asked to report observed correlation as a function of the sample correlation under varying conditions of visualization method, sample size and observation time. A statistical model is proposed to describe the correlation judgment process. The accuracy and the bias in the judgments in different conditions are established by interpreting the parameters in this model. A discriminability index is proposed to characterize the performance accuracy in each experimental condition. Moreover, a statistical test is applied to derive whether or not the human sensation scale differs from a theoretically optimal (that is, unbiased) judgment scale. Based on these analyses, we conclude that users can reliably distinguish twice as many different correlation levels when using scatterplots as when using PCPs. We also find that there is a bias towards reporting negative correlations when using PCPs. Therefore, we conclude that scatterplots are more effective than parallel plots in supporting visual correlation analysis.
Luminescence-induced photorefractive spatial solitons
Authors: Fazio E. , Alonzo M. , Devaux F. , Toncelli A. , Argiolas N. , Bazzan M. , Sada C. , Chauvet M.
Published: March 2010

We report the observation of spatial confinement of a pump beam into a photorefractive solitonic channel induced by luminescence [luminescence induced spatial soliton (LISS)]. Trapped beams have been obtained in erbium doped lithium niobate crystals at concentrations as high as 0.7 mol % of erbium. By pumping at 980 nm, erbium ions emit photons at 550 nm by two-step absorption, wavelength which can be absorbed by lithium niobate and originates the photorefractive effect. The luminescence at 550 nm generates at the same time the solitonic channel and the background illumination reaching a steady-state soliton regime.
Methodological assessment of kinetic Monte Carlo simulations of organic photovoltaic devices: The treatment of electrostatic interactions
Authors: Casalegno Mosè , Raos Guido , Po Riccardo
Published: March 2010

The kinetic Monte Carlo (KMC) method provides a versatile tool to investigate the mechanisms underlying photocurrent generation in nanostructured organic solar cells. Currently available algorithms can already support the development of more cost-efficient photovoltaic devices, but so far no attempt has been made to test the validity of some fundamental model assumptions and their impact on the simulation result. A meaningful example is given by the treatment of the electrostatic interactions. In most KMC models, electrostatic interactions are approximated by means of cutoff based potentials, irrespective of the long-range nature of the Coulomb interaction. In this paper, the reliability of such approximation is tested against the exact Ewald sum. The results under short-circuit and flat-band conditions show that use of cutoff-based potentials tends to underestimate real device performance, in terms of internal quantum efficiency and current density. Together with this important finding, we formalize other methodological aspects which have been scarcely discussed in the literature.
Compact and flexible basis functions for quantum Monte Carlo calculations
Authors: Petruzielo F. R. , Toulouse Julien , Umrigar C. J.
Published: March 2010

Molecular calculations in quantum Monte Carlo frequently employ a mixed basis consisting of contracted and primitive Gaussian functions. While standard basis sets of varying size and accuracy are available in the literature, we demonstrate that reoptimizing the primitive function exponents within quantum Monte Carlo yields more compact basis sets for a given accuracy. Particularly large gains are achieved for highly excited states. For calculations using nondiverging pseudopotentials, we introduce Gauss–Slater basis functions that behave as Gaussians at short distances and Slaters at long distances. These basis functions further improve the energy and fluctuations of the local energy for a given basis size. Gains achieved by exponent optimization and Gauss–Slater basis use are exemplified by calculations for the ground state of carbon, the lowest lying excited states of carbon with S5o, P3o, D1o, and F3o symmetries, carbon dimer, and naphthalene. Basis-size reduction enables quantum Monte Carlo treatment of larger molecules at high accuracy.
Isabelle Vernos: Motoring around the mitotic spindle
Authors: Sedwick Caitlin
Published: March 2010

Vernos uses cutting-edge microscopy to track spindle assembly in Xenopus eggs.
The SUMO protease SENP6 is essential for inner kinetochore assembly
Authors: Mukhopadhyay Debaditya , Arnaoutov Alexei , Dasso Mary
Published: March 2010

We have analyzed the mitotic function of SENP6, a small ubiquitin-like modifier (SUMO) protease that disassembles conjugated SUMO-2/3 chains. Cells lacking SENP6 showed defects in spindle assembly and metaphase chromosome congression. Analysis of kinetochore composition in these cells revealed that a subset of proteins became undetectable on inner kinetochores after SENP6 depletion, particularly the CENP-H/I/K complex, whereas other changes in kinetochore composition mimicked defects previously reported to result from CENP-H/I/K depletion. We further found that CENP-I is degraded through the action of RNF4, a ubiquitin ligase which targets polysumoylated proteins for proteasomal degradation, and that SENP6 stabilizes CENP-I by antagonizing RNF4. Together, these findings reveal a novel mechanism whereby the finely balanced activities of SENP6 and RNF4 control vertebrate kinetochore assembly through SUMO-targeted destabilization of inner plate components.
The Golgi and the centrosome: building a functional partnership
Authors: Sütterlin Christine , Colanzi Antonino
Published: March 2010

The mammalian Golgi apparatus is characterized by a ribbon-like organization adjacent to the centrosome during interphase and extensive fragmentation and dispersal away from the centrosome during mitosis. It is not clear whether this dynamic association between the Golgi and centrosome is of functional significance. We discuss recent findings indicating that the Golgi–centrosome relationship may be important for directional protein transport and centrosome positioning, which are both required for cell polarization. We also summarize our current knowledge of the link between Golgi organization and cell cycle progression.
Basic hydrodynamics of Richtmyer–Meshkov-type growth and oscillations in the inertial confinement fusion-relevant conditions
Authors: Aglitskiy Y. , Velikovich A. L. , Karasik M. , Metzler N. , Zalesak S. T. , Schmitt A. J. , Phillips L. , Gardner J. H. , Serlin V. , Weaver J. L. , Obenschain S. P.
Published: March 2010

In inertial confinement fusion (ICF), the possibility of ignition or high energy gain is largely determined by our ability to control the Rayleigh–Taylor (RT) instability growth in the target. The exponentially amplified RT perturbation eigenmodes are formed from all sources of the target and radiation non-uniformity in a process called seeding. This process involves a variety of physical mechanisms that are somewhat similar to the classical Richtmyer–Meshkov (RM) instability (in particular, most of them are active in the absence of acceleration), but differ from it in many ways. In the last decade, radiographic diagnostic techniques have been developed that made direct observations of the RM-type effects in the ICF-relevant conditions possible. New experiments stimulated the advancement of the theory of the RM-type processes. The progress in the experimental and theoretical studies of such phenomena as ablative RM instability, re-shock of the RM-unstable interface, feedout and perturbation development associated with impulsive loading is reviewed.
Turbulent mixing and beyond
Authors: Abarzhi S. I. , Sreenivasan K. R.
Published: March 2010

Turbulence is a supermixer. Turbulent mixing has immense consequences for physical phenomena spanning astrophysical to atomistic scales under both high- and low-energy-density conditions. It influences thermonuclear fusion in inertial and magnetic confinement systems; governs dynamics of supernovae, accretion disks and explosions; dominates stellar convection, planetary interiors and mantle-lithosphere tectonics; affects premixed and non-premixed combustion; controls standard turbulent flows (wall-bounded and free—subsonic, supersonic as well as hypersonic); as well as atmospheric and oceanic phenomena (which themselves have important effects on climate). In most of these circumstances, the mixing phenomena are driven by non-equilibrium dynamics. While each article in this collection dwells on a specific problem, the purpose here is to seek a few unified themes amongst diverse phenomena.