bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface‐graft hyperbranched polymer via self‐condensing atom transfer radical polymerization from zinc oxide nanoparticles
Authors: Liu Peng , Wang Tingmei
Published: August 2007

We present the synthesis of hyperbranched polymer grafted zinc oxide (ZnO) hybrid nanoparticles by self‐condensing vinyl polymerization (SCVP) via surface‐initiated atom transfer radical polymerizations (SI‐ATRP) from ZnO surfaces. ATRP initiators were covalently linked to the surfaces of ZnO particles, followed by SCVP of an initiator‐monomer (“inimer”) which has both a polymerizable group and an initiating group in the same molecule. Well‐defined polymer chains were grown from the surfaces to yield hybrid nanoparticles comprised of ZnO cores and hyperbranched polymer shells having multifunctional chlorobenzyl functional end groups. The percentage of grafting (PG%) achieved 429% in 6 h, calculated from the elemental analysis results. The hybrid nanoparticles were also characterized using Fourier transform infrared spectroscopy, UV–vis absorption spectroscopy, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and transmission electron microscopy. POLYM. ENG. SCI., 47:1296–1301, 2007. © 2007 Society of Plastics Engineers
Study of thermally poled and corona charged poly(vinylidene fluoride) films
Authors: Jiang Yadong , Ye Yun , Yu Junsheng , Wu Zhiming , Li Wei , Xu Jianhua , Xie Guangzhong
Published: August 2007

The effect of thermal poling and corona charging on the structure and characteristics of poly(vinylidene fluoride) films (PVDF) was investigated. The structure and chemical change of PVDF films with different polarizing treatments was examined using Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy, respectively. The characteristics including piezoelectric coefficients, ferroelectric hysteresis, and leakage current were measured. It was found that both polarized methods contribute to dramatic improvement on the piezoelectricity and ferroelectricity of PVDF films, while thermal poling leads to structure change with the generation of new carbon composition. The reason to cause leakage current was also analyzed. POLYM. ENG. SCI., 47:1344–1350, 2007. © 2007 Society of Plastics Engineers
Controlled drug release through carboxymethyl‐chitosan/poly(vinyl alcohol) blend films
Authors: Wang Ling‐Chong , Chen Xi‐Guang , Yu Le‐Jun , Li Pi‐Wu
Published: August 2007

Carboxymethyl‐chitosan (CMCS)/poly(vinyl alcohol) (PVA) blend film was studied for an application as a coating material in the site‐specific drug delivery system. Films were prepared by blending varying amounts of 4 wt% CMCS with 4 wt% PVA, casting and drying at 50°C for 24 h. The cross‐sectional SEM micrograph of the film revealed that an increase in the amount of CMCS in the blend resulted in the film surface less smooth in the dry state and the network less uniform and more porous in the hydrated state, which became appreciable at 50%. The inclusion of CMCS in the blend also made the swelling of the films pH‐dependent, and lead to an increase in the degree of swelling with pH increase. When the permeation of three model drugs, salicylic acid, theophyline, and ornidazole, was studied using a static diffusion vessel, it followed a zero‐order kinetics and increased with an increase in the CMCS content in the blend, a decrease in the molecular weight of drug, an increase in the pH of medium, and a decrease in the film thickness. POLYM. ENG. SCI., 47:1373–1379, 2007. © 2007 Society of Plastics Engineers
Melt compounding of polypropylene‐based clay nanocomposites
Authors: Li J. , Ton‐That M.‐T. , Leelapornpisit W. , Utracki L.A.
Published: August 2007

Polypropylene (PP)‐based nanocomposites containing 4 wt% maleic anhydride grafted PP (PP‐g‐MA) and 2 wt% Cloisite 20A (C20A) were prepared using various processing devices, viz., twin‐screw extruder (TSE), single‐screw extruder (SSE), and SSE with an extensional flow mixer (EFM). Two processing methods were employed: (I) masterbatch (MB) preparation in a TSE (with 10 wt% C20A and clay/compatibilizer ratio of 1:2), followed by dilution in TSE, SSE, or SSE + EFM, to 2 wt% clay loading; (II) single pass, i.e., directly compounding of dry‐blended PP‐g‐MA/clay in TSE, SSE, or SSE + EFM. It has been indicated that the quality of clay dispersion, both at micro‐ and nanolevel, of the nanocomposites depends very much on the operating conditions during processing, such as mixing intensity and residence time, thus affecting the mechanical performance. Besides that the degradation of the organoclay and the matrix is also very sensitive to these parameters. According to results of X‐ray diffraction, field emission gun scanning electron microscopy, transmission electron microscopy, and mechanical tests, the samples prepared with MB had better overall clay dispersion, which resulted in better mechanical properties. The processing equipment used for diluting MB had a marginal influence on clay dispersion and nanocomposite performance. POLYM. ENG. SCI., 47:1447–1458, 2007. © 2007 Society of Plastics Engineers
Real‐time diagnosis of co‐injection molding using ultrasound
Authors: Cheng Chin‐Chi , Ono Yuu , Jen Cheng‐Kuei
Published: August 2007

Co‐injection molding, also known as sandwich molding, is a process in which two or more polymers are laminated together in a mold cavity. Integrated ultrasonic sensors embedded into a mold insert of a co‐injection‐molding machine have been used for real‐time, nonintrusive, and nondestructive diagnosis of co‐injection‐molding processes. Diagnosis of core arrival, core flow speed, part solidification, part detachment from the mold, thickness of skin and core, and core length at the mold was demonstrated. It is found that core flow speed and peak cavity pressure monotonically increased and decreased with the core volume percentage, respectively. Thicknesses of the skin and core of the molded part were estimated using the presented ultrasonic technique during molding with an accuracy better than ±17%. In addition, the core length had correlation with core thickness, core flow speed, and peak cavity pressure. Among them, the core thickness measured by the ultrasonic technique had the better correlation. This technique enables process optimization, the maximum process efficiency, and in‐process quality assurance of the molded parts. POLYM. ENG. SCI., 47:1491–1500, 2007. © 2007 Society of Plastics Engineers
Synthesis of cyclic peptides and peptide libraries on a new disulfide linker
Authors: Tegge Werner , Bautsch Wilfried , Frank Ronald
Published: August 2007

A new cysteine‐based disulfide linker for Fmoc solid phase peptide synthesis was developed (Fmoc‐Cys(3‐mercapto‐3‐methylbutanoic acid)OPp) that allows the on‐resin assembly and side chain deprotection of cyclic peptides. Model peptides and a cyclic peptide library of the structure [a‐a‐x‐x‐a‐a‐c] composed of D‐amino acids were assembled and the synthesis and cleavage conditions studied. The best cyclization results were obtained with PyBOP/HOAt/diisopropylethyl amine. Racemization rates of the cysteine in the analyzed model sequences were between 5.2 and 12.3%. Cleavage of the disulfide bond was best carried out with DTT in 50% 2‐propanol/100 mM ammonium bicarbonate. The cleaved peptides can be used directly in biological assays. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Dehnungsabhängige Berechnung vierseitig gelagerter Querschnittselemente unter Druckbeanspruchung im Brandfall
Authors: Knobloch Markus , Fontana Mario
Published: August 2007

Das Tragverhalten vierseitig gelagerter Querschnittselemente bei Brandbeanspruchung wird durch das lokale Beulverhalten, das nicht‐lineare Spannungs‐Dehnungsverhalten von Stahl bei erhöhten Temperaturen, ungleichmäßige Temperaturverteilungen sowie thermische Dehnungen und Zwängungen beeinflusst. Diese Veröffentlichung schlägt ein neues Modell zur Berechnung des Last‐Stauchungsverhaltens von vierseitig gelagerten Querschnittselementen im Brandfall vor. Das Modell verwendet dehnungsabhängige Traglastkurven. Mit diesen Kurven kann außerdem das Kraft‐Erwärmungsverhalten von vierseitig gelagerten Querschnittselementen mit gleichmäßiger und ungleichmäßiger Temperaturverteilung berechnet werden. Das vereinfachte Berechnungsmodell vermeidet eine Klassifizierung und berücksichtigt das lokale Beulen, das nicht‐lineare Materialverhalten von Stahl bei erhöhten Temperaturen, thermische Dehnungen und Spannungen sowie thermische Zwängungen.
Eine Glaskuppel über dem Nordhof des Landtages von Schleswig‐Holstein
Authors: Engelsmann Stephan , Sobek Werner
Published: August 2007

Der Neubau einer Glaskuppel über dem Nordhof des Landtages von Schleswig‐Holstein in Kiel ist Teil der umfassenden Ergänzungs‐ und Modernisierungsmaßnahmen für das bestehende Landtagsgebäude. Erscheinungsbild und Tragverhalten sind bestimmt durch die Randbedingung eines unter Denkmalschutz stehenden Gebäudebestandes und die aus dem Gebäudebestand abgeleitete ungewöhnliche Geometrie der Glaskuppel. Der Beitrag beschreibt die Objektplanung und die Tragwerksplanung für die Glaskuppel sowie deren Tragverhalten.
Effect of soil conditions on the response of reinforced concrete tall structures to near‐fault earthquakes
Authors: Galal K. , Naimi M.
Published: August 2007

Characteristics of near‐fault earthquakes (NFE) are particularly different from that of the far‐field ones. Far‐field ground motions are characterized by low peak ground acceleration (PGA) and high frequency, whereas near‐fault ground motions have a high peak ground velocity (PGV) and long period pulse. Several recent earthquakes, e.g. 1992 Landers, 1994 Northridge, 1995 Kobe, and 1999 Chichi earthquake events, have caused substantial damage to near‐fault flexible structures. The nonlinear dynamic behaviour of tall reinforced concrete (RC) frame structures subjected to NFE records is influenced by the characteristics of the foundation soil. The assumption of a fixed‐base model for this type of structure might not adequately represent their seismic response. Therefore, the seismic performance evaluation analysis should take into account the soil–structure interaction (SSI). In this study, the seismic performance of a 20‐storey and a 6‐storey RC frame structures with fixed‐base and flexible‐base conditions is evaluated. The characteristics of the flexible‐base models cover four types of soils, namely, soft soil, medium soil, stiff soil and a rock soil, as classified by the International Building Code. A set of 13 near‐fault acceleration time histories recorded on the four types of soil from major earthquake events is selected for the analysis. Three criteria for scaling the records were considered, namely, same maximum spectral acceleration, same spectral acceleration at fundamental period of fixed‐base model, and same spectral acceleration at fundamental period of flexible‐base model. The analysis evaluates the effect of SSI on the dynamic behaviour by comparing the response of the flexible‐base model to the fixed‐base model of the structure when subjected to different earthquake records on a specific soil type. It is concluded that SSI effects could vary significantly according to the characteristics of the NFE record, the scaling criterion and the seismic performance indicator representing the SSI. This observation is valid for tall and low‐rise structures. Copyright © 2007 John Wiley & Sons, Ltd.
Unemployment Rates and Trauma Admissions
Authors: Madan Atul K. , Sapozhnik Julie , Tillou Areti , Raafat Aml , McSwain Norman E
Published: August 2007

In this article, we tested the hypothesis that the number and demographic characteristics of admissions to our trauma center were related to unemployment rates. The correlation study was conducted at The American College of Surgeons‐verified level I trauma center in our area (New Orleans, Louisiana). It included all trauma admissions. Monthly unemployment rate data from our area were obtained from the Bureau of Labor Statistics. The hospital trauma registry supplied trauma emergency room admissions and demographic data. Mean daily trauma admissions were calculated for each month. Pearson correlations were used for statistical analysis. Over 24,000 trauma admissions occurred over a six‐year period. Unemployment rates correlated with penetrating trauma admissions (r = 0.50; p < 0.001). Interestingly, unemployment rates inversely correlated with total trauma admissions (r = −0.73; p < 0.001), blunt trauma admissions (r = −0.81; p < 0.001), and ratio of blunt‐to‐penetrating trauma admissions (r = −0.82; p < 0.001). Higher percentage of male patients (r = 0.66; p < 0.001), percentage of African‐American patients (r = 0.53; p < 0.001), and mortality (r = 0.56; p < 0.001) correlated positively with higher unemployment rates. We concluded that as unemployment rates decrease, emergency room penetrating trauma admissions decrease, while total and blunt trauma admissions increase. As the socioeconomic status (measured by unemployment rates) of the community changes, so do the demographic make‐up and mortality of the trauma population. Our findings suggest that during times of economic hardships, certain population groups are at higher risk for trauma. Prevention should be aimed accordingly.
Awareness and Attitudes Regarding Prenatal Testing among Texas Women of Childbearing Age
Authors: Case Amy P. , Ramadhani Tunu A. , Canfield Mark A. , Wicklund Catherine A.
Published: August 2007

Despite increased visibility and availability of prenatal testing procedures, very little is known about the attitudes among the populace toward these procedures. Using a computer assisted telephone interview of pregnant and non‐pregnant women of childbearing age we analyze awareness and attitudes regarding prenatal tests among a diverse group of women of childbearing age in Texas. We also examine maternal characteristics associated with awareness and the willingness to undergo these procedures. While 89% were aware that such tests are available, younger, black and less educated women were less likely to know about prenatal tests for birth defects. Seventy‐two percent of respondents said they would want their baby tested while Hispanic and black women were significantly more likely to express an interest than non‐Hispanic whites. This study demonstrates the variability of knowledge and beliefs and confirms the importance of taking time to understand an individual's personal beliefs, knowledge and attitudes about prenatal diagnosis.
Determination of iodine value of palm oil based on triglyceride composition
Authors: Haryati T. , Che Man Y. B. , Ghazali H. M. , Asbi B. A. , Buana L.
Published: August 2007

The triglyceride (TG) composition of palm oil is normally determined by high‐performance liquid chromatography (HPLC). The HPLC chromatograms indicated a good separation of most of the TG components in the oil. The TG can be classified based on either the TG groups, i.e., triunsaturated, monosaturated, disaturated, or trisaturated, or the number of double bonds, i.e., zero, one, two, three, or four double bonds. The more unsaturated the fatty acid, the greater the iodine value (IV). Therefore, it is hypothesized that the IV of an oil can be determined based upon the TG composition of the oil. Based on the TG groups, stepwise regression analysis showed that the areas of the disaturated, trisaturated, and triunsaturated TG peaks could predict the IV with a coefficient of determination (R2) of 0.990. The regression based on the number of double bonds yielded a good regression equation with R2=0.992. The important variables were the peak area of the fatty acids that contained zero, one, two, and three double bonds. This study concludes that the TG composition can be used to predict the IV of palm oil. The best prediction model is obtained by using the number of double bonds in the TG as the independent variable.
Determination of Cis‐ and Trans‐18:1 fatty acid isomers in hydrogenated vegetable oils by high‐resolution carbon nuclear magnetic resonance
Authors: Miyake Yuko , Yokomizo Kazuhisa
Published: August 2007

Carbon nuclear magnetic resonance (13C NMR) methods for determining the composition of cis‐/trans‐ and positional isomers in hydrogenated vegetable oils were developed to reduce analytical time. By selecting appropriate olefinic carbon peaks and by measuring individual peak areas subsequent to the identification of isomeric peaks on the NMR spectrum, compositional results of the isomers coincided well with those obtained by conventional gas chromatography (GC). Therefore, it is highly beneficial to choose the 13C NMR method when analysis time is limited. Though the proposed 13C NMR method is promising, further development is needed. For the time being, combination with the traditional GC method is still encouraged for precise compositional analysis of cis‐/trans‐ and positional isomers.
Effects of tocopherols, ascorbyl palmitate, and lecithin on autoxidation of fish oil
Authors: Hamilton R. J. , Kalu C. , McNeill G. P. , Padley F. B. , Pierce J. H.
Published: August 2007

The effects of α‐, γ/δ, and δ‐tocopherol concentrates (0.2–2.0%) alone and in combination with ascorbyl palmitate (0.1%) and lecithin (0.5%) on oxidative stability and flavor of fish oil were studied. Stability was assessed on oil stored in air at 20°C by peroxide value (PV) and off‐flavor formation. Polymer content, para‐anisidine value, and conjugation were used to characterize selected samples. When used alone, the protective effect of the tocopherols, as measured by PV, was δ≫γ/δ≫α, especially at the 2% concentration. Binary systems of ascorbyl palmitate‐lecithin and lecithin‐γ/δ or‐δ‐tocopherol were strongly synergistic in delaying peroxidation. The ternary blends provided the greatest protection against autoxidation. Refined fish oil with 2% δ‐tocopherol, 0.1% ascorbyl palmitate, and 0.5% lecithin showed no significant peroxidation at 20°C over a period of 6 mon. The original antioxidant effect noted for the ternary systems in delaying peroxidation was not reflected in improved flavor stability. Off‐flavors developed within 3 wk, making the oils unsuitable for use at high concentrations in ambient products that are unprotected from air.
Polymorphism and solidification kinetics of the binary system POS‐SOS
Authors: Rousset Ph. , Rappaz M. , Minner E.
Published: August 2007

As a first approach to modeling the crystallization behavior of cocoa butter, the binary system of its two major components, 1‐palmitoyl‐2‐oleoyl‐3‐stearoyl‐s n‐glycerol (POS) and 1,3‐distearoyl‐2‐oleoyl‐s n‐glycerol (SOS), was studied. Differential scanning calorimetry, coupled with polarized light microscopy, was used to determine the phase diagrams of the various polymorphic forms (the most metastable sub‐α and α, intermediate δ and β′, and stable β). Associated theoretical phase diagrams were also built. The presence of a solid solution for β and the ideal behavior of α were confirmed. Kinetics of isothermal solidification as a function of temperature were studied for three compositions of the POS‐SOS system. Results were displayed as time‐temperature‐transformation (TTT) diagrams and crystal morphology maps. Dependence of the crystallization kinetics on composition of the binary system was interpreted in terms of nucleation and growth mechanisms. The asymmetry of the POS molecule induces a slower growth rate of the mixture when the concentration of this triacylglycerol is increased. Solidification kinetics during continuous cooling were studied at various cooling rates for the system POS‐SOS 25:75. Experimental results were compared with numerical predictions of a solidification model based upon TTT data and an additivity principle. The calculated and measured volume fractions of the different phases formed and times of onset and finish of the solidification were in good agreement.
Genetik intermediärer Phänotypen
Authors: Kronenberg F. , Heid I.M.
Published: August 2007

Die Entstehung komplexer Erkrankungen wie koronare Herzkrankheit oder Diabetes mellitus wird durch zahlreiche Gene beeinflusst, von welchen jedes einzelne einen oft eher geringen Beitrag liefert. Der Nachweis, dass bestimmte genetische Varianten mit komplexen Erkrankungen assoziiert sind, ist oft schwer zu führen und bedarf großer, gut charakterisierter Patienten- und Kontrollgruppen. Alternativ und Erfolg versprechend ist die Untersuchung so genannter intermediärer Phänotypen. Dabei handelt es sich um Parameter, die mit der Entstehung der Erkrankung in Zusammenhang stehen, genetisch determiniert sind und einen Teilaspekt unter mehreren im Entstehungsmechanismus der Erkrankung repräsentieren. Dadurch kommt es zu einer Schärfung des Phänotyps und zu einer Reduktion der genetischen Heterogenität. Durch Untersuchung der Genetik solcher intermediärer Phänotypen statt der Genetik der Erkrankung an sich kann dieser Teilaspekt aufgeklärt werden. Besonders geeignet als intermediäre Phänotypen sind quantitative, gut messbare biochemische Parameter, wodurch im Gegensatz zu qualitativen Parametern eine deutlich verbesserte statistische Power erreicht werden kann.
Rereading the British Mandate in Palestine: Gender and the Urban–Rural Divide in Education
Authors: JAD ISLAH
Published: August 2007

Under Ottoman rule, the relations between native Arabs and Jews in Palestine were based on understanding and respect, as was the case between Muslims and Christians. Shared enrolment of Jewish, Muslim, and Christian students in the same schools—either the Jewish Alliance Israelite schools (established in 1882) or in the nizamiyya, the Ottoman public schools first established by the Turkish law of 1869—promoted mutual understanding for a small elite. In contrast, the British Mandate policy in education played a major role in reshaping national, regional, and class and gender identities. It was through education that two separate national entities were developed, the urban/rural division was deepened, class boundaries were rendered unbridgable, and gender identities were molded to suit the British model.
THE STRUCTURE OF THE FIHRIST: IBN AL-NADIM AS HISTORIAN OF ISLAMIC LEGAL AND THEOLOGICAL SCHOOLS
Authors: Stewart Devin
Published: August 2007

Compiled in 987–88, Ibn al-Nadim's work al-Fihrist (The Catalogue) needs little introduction to scholars of Middle Eastern and Islamic history. Countless specialized studies have used the Fihrist as a source of data. Because it includes the titles of a large number of works that are no longer extant, as well as biographical information on little-known early authors, it throws light on otherwise obscure facets of medieval Islamic intellectual history in many fields. Choice anecdotes, such as the account of al-Maءmun's (r. 813–33) conversation with Aristotle in a dream, considered to have triggered the translation movement, have been quoted in numerous studies. Little attention has been paid, however, to Ibn al-Nadim as a thinker, despite the fact that the Fihrist, like Dewey's decimal system, is as much an exercise in mapping out the organization of human knowledge as a simple inventory of book titles. The following remarks focus first on the methods Ibn al-Nadim adopted in compiling the Fihrist and second on the arguments he makes about the history of Islamic sciences, in many cases not explicitly but through order, presentation, and the calculus of inclusion and exclusion, emphasis and de-emphasis. Particular attention will be paid to the Islamic legal madhhabs and theological schools. Determining Ibn al-Nadim's views on these topics, as an Imami Shiʿi and Muʿtazili theologian, promises to provide a better understanding of his conception of the Islamic sciences, the overall message of his work, and Islamic intellectual history itself.
WHERE EAST MEETS WEST: SUFISM, CULTURAL RAPPROCHEMENT, AND POLITICS
Authors: Hatina Meir
Published: August 2007

The growing gap in power and wealth between the West and the Muslim world from the end of the 18th century onward has engendered periodic demands for the rejuvenation of Islamic thought as a prerequisite for rehabilitating the status of the Muslim community. In Egypt and the Fertile Crescent, this quest for reform was led by Muslim modernists and Salafis (advocates of a return to ancestral piety and practice) in the late 19th century. Inter alia, these reformists opposed the gatekeepers of Islamic tradition—the establishment ʿulamaء as well as the popular Sufi orders or fraternities (ṭuruq). The Sufi orders were portrayed by their reformist adversaries as at best irrelevant to social change and at worst as responsible for the backwardness of Muslim society. Criticism of customs and ceremonies in popular Islam, especially the cult of saints—denounced as a deviation from Islam—also had nationalist overtones: these rituals were attacked for fostering national passivity and a detachment from reality, in addition to eliciting ridicule by foreigners. Religious reform was thus interwoven with the quest for national pride and power.
A RESPONSE TO MICHAEL GUNTER'S REVIEW OF THE ARMENIAN MASSACRES IN OTTOMAN TURKEY: A DISPUTED GENOCIDE (IJMES 38 [2006]: 598–601)
Authors: KÉCHICHIAN JOSEPH A.
Published: August 2007

Perhaps inadvertently, IJMES rendered a disservice to its readers by allowing Michael M. Gunter to review The Armenian Massacres in Ottoman Turkey: A Disputed Genocide, by Guenter Lewy, because not only the book but also the reviewer pose serious problems.
The Politics of the Epic: Wordsworth, Byron, and the Romantic Redefinition of Heroism
Authors: Cantor Paul A.
Published: August 2007

Traditionally, the epic focused on the heroic deeds of great public figures, but the Romantics remade the genre into something more personal, making the poet himself the hero of their epics. The Romantic disillusionment with politics, flowing from the failure of the French Revolution, lies behind their revaluation of heroism. The turn to nature, which the Romantics present as immediate, turns out to be mediated by their political experience. Wordsworth's The Prelude and Byron's Childe Harold's Pilgrimage are good examples of the Romantic transformation of the epic and provide a case study in the relation of politics and literature, specifically the politics of literary form.
Formation of a pronival rampart on sub-Antarctic Marion Island
Authors: Hedding David W. , Sumner Paul D. , Holness Stephen D. , Meiklejohn K. Ian
Published: August 2007

The formation of a pronival (protalus) rampart on sub-Antarctic Marion Island is investigated. Morphological attributes show debris at the angle of repose on the rampart's proximal slope and at a lower angle on the distal slope. Relative-age dating, based on the percentage moss cover and weathering rind thickness of the clastic component, indicates accumulation mainly on the proximal slope and rampart crest, implying upslope (retrogressive) accumulation. This contrasts with a previously published model for pronival ramparts, which proposes rampart growth by addition of material to the distal slope. Development of the Marion Island rampart is suggested to result from the control exerted by a relatively low-angled surface and a shrinking snowbed. A small debris step formed on the proximal slope appears to be a response to decreased snowfalls due to changing climate over the last c. 50 years. Growth rate of the rampart is considered to be variable during the Holocene in response to changes in climate and debris supply.
First evidence of a “Barrovian”-type metamorphic regime in the Ross orogen of the Byrd Glacier area, central Transantarctic Mountains
Authors: Talarico F.M. , Stump E. , Gootee B.F. , Foland K.A. , Palmeri R. , Van Schmus W.R. , Brand P.K. , Ricci C.A.
Published: August 2007

The Selborne Group comprises two metamorphic rock units, the muscovite±dolomite bearing Madison Marble and the biotite-muscovite±quartz-calcite Contortion Schist, which contains thick lenses of variably deformed metabasalts and metaconglomerates. Petrological and structural data indicate a polyphase metamorphic evolution including: i) an early stage of upper greenschist regional metamorphism (P = ~0.15–0.3 GPa; T = ~380–450°C), ii) prograde metamorphism during D1up to amphibolite facies peak conditions (P = 0.58–0.8 GPa, T = ~560–645°C), iii) syn-D2unloading-cooling retrograde metamorphism, iv) a post-D2contact metamorphic overprint at variable T between 450 and 550°C and ~0.2 GPa connected to the emplacement of granitic plutons and felsic dyke swarms. Geochronological data constrain the polyphase syn-D1/D2evolution between ~ 510 and 492 Ma. A similar metamorphic path, including a medium P stage but at lower T conditions, is documented in greenschist facies metabasalts within the Byrd Group in the Mount Dick area. The metamorphic pattern and close lithostratigraphic matching between Selborne Group and Byrd Group sharply contrast with the high-grade Horney Formation that is exposed north of the Byrd Glacier and corroborate the hypothesis that the Byrd Glacier discontinuity marks a first-order crustal tectonic boundary crossing the Ross orogen.
On the size complexity of universal accepting hybrid networks of evolutionary processors
Authors: MANEA FLORIN , MARTIN-VIDE CARLOS , MITRANA VICTOR
Published: August 2007

In this paper we discuss the following interesting question about accepting hybrid networks of evolutionary processors (AHNEP), which are a recently introduced bio-inspired computing model. The question is: how many processors are required in such a network to recognise a given language L? Two answers are proposed for the most general case, when L is a recursively enumerable language, and both answers improve on the previously known bounds. In the first case the network has a number of processors that is linearly bounded by the cardinality of the tape alphabet of a Turing machine recognising the given language L. In the second case we show that an AHNEP with a fixed underlying structure can accept any recursively enumerable language. The second construction has another useful property from a practical point of view as it includes a universal AHNEP as a subnetwork, and hence only a limited number of its parameters depend on the given language.
A calculus of open modules: call-by-need strategy and confluence
Authors: FAGORZI SONIA , ZUCCA ELENA
Published: August 2007

We present a simple module calculus where selection and execution of a component is possible onopenmodules, that is, modules that still need to import some external definitions. Hence, it provides a kernel model for a computational paradigm in which standard execution (that is, execution of a single computation described by a fragment of code) can be interleaved with operations at the meta-level, which can manipulate in various ways the context in which this computation takes place. Formally, this is achieved by introducingconfigurationsas basic terms. These are, roughly speaking, pairs consisting of an (open, mutually recursive) collection of named components and a term representing a program running in the context of these components. Configurations can be manipulated by classical module/fragment operators, hence reduction steps can be either execution steps of the program or steps that perform module operations (calledreconfigurationsteps).

Since configurations combine the features of lambda abstractions (first-class functions), records, environments with mutually recursive definitions and modules, the calculus extends and integrates both traditional module calculi and recursive lambda calculi. We state confluence of the calculus, and propose different ways to prevent errors arising from the lack of some required component, either by a purely static type system or by a combination of static and run-time checks. Moreover, we define a call-by-need strategy that performs module simplificationonly when needed and only once, leading to a generalisation of call-by-need lambda calculi that includes module features. We prove the soundness and completeness of this strategy using an approach based on information content, which also allows us to preserve confluence, even when local substitution rules are added to the calculus.
Tolerance of submergence in rice: gene studies using differential display technique
Authors: Yong-Hua Chen , Sen Zhao , Qin-Quan Yan , Yang-Sheng Li , Xing-Rong Wu , Guo-Ying Xiao
Published: August 2007

Gene expression profiles between submergence rice (Oryza sativa ssp. indica) varieties, tolerant FR13A and sensitive IR39595-503-2-1-2, under submergence stress were identified using differential display reverse transcriptase-polymerase chain reaction (DDRT-PCR). A total of 1428 bands were amplified with 40 pairs of primers, of which 102 were significantly different between the two lines. The differential display ratio was 7.1%. Among 42 differential display bands derived from the submergence tolerant variety, the expression of seven fragments was confirmed by Northern blot analysis. The analysis of their sequences indicated that four of them showed high homology with genes related to a water stress response: genes encoding ATP-binding protein, isocitrate dehydrogenase, NADH dehydrogenase and terminal acetyltransferase, respectively. The remaining three fragments were novel cDNA fragments.
Cloning and expression analysis of porcine small adipocyte factor 1 (SMAF1) gene
Authors: Hong-Wen Yang , Rong Zheng , Feng-E Li , Si-Wen Jiang
Published: August 2007

cDNA of the porcine small adipocyte factor 1 (SMAF1) gene was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) with degenerate primers designed according to the conserved sequences between human and mouse genes. The cDNA (GenBank accession No. DQ191892) containing a complete encoding region was 256 bp in length, sharing 86 and 78% identity with that of human and mouse, respectively. Comparison of the deduced amino acid sequence between porcine SMAF1 and the human, mouse, cattle and rat protein showed that the amino acid similarity was 81, 67, 84 and 70%, respectively. The results of semi-quantitative RT-PCR showed that the porcine gene was expressed abundantly in adipose tissue, and at a significantly lower level in lean-type pigs (Large White pigs) than in lard-type pigs (Meishan pigs) at the age of 4 months (P<0.05). The results suggest that the porcine SMAF1 gene may have similar functions as in other species, that is, it may regulate adipogenesis and/or adipocyte function.
Influence of maize Lc regulatory gene on flower colour of transgenic tobacco and petunia
Authors: Chi-Chun Yang , Jing-Juan Yu , Qian Zhao , Deng-Yun Zhu , Guang-Ming Ao
Published: August 2007

The Lc regulatory gene affects the formation of anthocyanin in plants. XY355 promoter, a petal-specific promoter, was obtained from the genome of rape (Brassica napus) by polymerase chain reaction (PCR). A plant expression vector, pXY60, was constructed, which contained the maize Lc regulatory gene under the control of the XY355 promoter. The vector was introduced into tobacco (Nicotiana tabacum) and petunia (Petunia hybrida) by an Agrobacterium tumefaciens-mediated method. The flower colour of some transgenic tobacco plants was changed from light red to deep red and that of some transgenic petunia plants had changed from white to light purple.
Tide‐surge interaction and its role in the distribution of surge residuals in the North Sea
Authors: Horsburgh K. J. , Wilson C.
Published: August 2007

Storm surges are the sea level response to meteorological conditions. Scientists and engineers need to understand the interaction of surges with the tide in order to provide better estimates of extreme sea level for use in coastal defense. Using data from five tide gauges, spaced equally along the North Sea coastline around the UK, we show that the mode of peak residual occurrence is everywhere 3 to 5 hours before the nearest high water. We reveal a previously unobserved mode that falls 1 to 2 hours prior to high water, although this cluster is not associated with the highest residuals. A simple mathematical explanation for surge clustering on the rising tide is presented. The phase shift of the tidal signal is combined with the modulation of surge production due to water depth in a model that provides a good description of the residual data set. The results contain several features of interest for flood risk management. We show that large, locally generated surges are precluded close to high water. For physically realistic arrival times of any travelling surge component, the residual peak will avoid high water for any finite tidal phase shift. Furthermore, increasing the tidal range reduces the risk of residual peaks near high water. We draw attention to the existence of critical time and space scales for surge development and decay. For reliable operational forecasts of sea level, coastal numerical models need to reproduce both tides and surges with improved accuracy.
An improved algorithm for retrieving surface downwelling longwave radiation from satellite measurements
Authors: Zhou Yaping , Kratz David P. , Wilber Anne C. , Gupta Shashi K. , Cess Robert D.
Published: August 2007

Zhou and Cess (2001) developed an algorithm for retrieving surface downwelling longwave radiation (SDLW) based upon detailed studies using radiative transfer model calculations and surface radiometric measurements. The algorithm links clear sky SDLW with surface upwelling longwave (LW) flux and column precipitable water vapor. For cloudy sky cases, the cloud liquid water path is used as an additional parameter to account for the effects of clouds. Despite the simplicity of the algorithm, it performs very well for most geographical regions except for those regions where the atmospheric conditions near the surface tend to be extremely cold and dry. Systematic errors are also found for scenes that are covered with ice clouds. An improved version of the algorithm prevents the large errors in the SDLW at low water vapor amounts by taking into account that, under such conditions, the SDLW and water vapor amount are nearly linear in their relationship. The new algorithm also utilizes cloud fraction and cloud liquid and ice water paths available from the Cloud and the Earth's Radiant Energy System (CERES) single‐scanner footprint (SSF) product to separately compute the clear and cloudy portions of the fluxes. The new algorithm has been validated against surface measurements at 29 stations around the globe for Terra and Aqua satellites. The results show significant improvement over the original version. Preliminary tests also suggest that the new algorithm works quite well for high elevation locations such as Tibet site where current satellite products exhibit large biases. The revised Zhou‐Cess algorithm is also slightly better or comparable to more sophisticated algorithms currently implemented in the CERES processing and will be incorporated as one of the CERES empirical surface radiation algorithms.
MultivariateL‐moment homogeneity test
Authors: Chebana F. , Ouarda T. B. M. J.
Published: August 2007

Several types of hydrological events are described with multivariate characteristics (droughts, floods, rain storms, etc.). When carrying out a multivariate regional frequency analysis for these events it is important to jointly consider all these characteristics. The aim of this paper is to extend the statistical homogeneity test of Hosking and Wallis (1993) to the multivariate case. As a tool, multivariateL‐moments are used to define the statistics and general copula models to describe the statistical behavior of dependent variables. The usefulness of the methodology is illustrated on flood events. Monte‐Carlo simulations are also performed for a bivariate Gumbel logistic model with Gumbel marginal distributions. Results illustrate the power of the proposed multivariateL‐moment homogeneity test to detect heterogeneity on the whole structure of the model and on the marginal distributions. In a bivariate flood setting, a comparison is carried out with the classical homogeneity test of Hosking and Wallis based on several types of regions.
Polar mesosphere summer echoes at Wasa, Antarctica (73°S): First observations and comparison with 68°N
Authors: Kirkwood S. , Wolf I. , Nilsson H. , Dalin P. , Mikhaylova D. , Belova E.
Published: August 2007

Polar mesosphere summer echoes (PMSE) have been observed for the first time at Wasa, Antarctica (73°S, 13°W, 61° geomagnetic). A new 54.5 MHz radar, MARA, operated first in Kiruna (68°N) during late summer 2006 and then at Wasa between 18 January and 5 February 2007. Operation in Kiruna allowed accurate cross calibration with the permanent 52 MHz radar ESRAD. PMSE at 73°S are found to have very similar characteristics to PMSE at 68°N. When observations from the same part of the summer season are compared, volume reflectivities show very similar distributions over different intensities, over height and over local‐time. PMSE at 68°N (65° geomagnetic) are stronger in the midnight sector, likely due to the different geomagnetic latitudes. Above 85 km altitude, weak PMSE have a higher occurrence rate at 73°S. The height of peak PMSE occurrence is ∼1 km higher at 73°S compared to 68°N.
Hydrogen is the central free intermediate during lignocellulose degradation by termite gut symbionts
Authors: Pester Michael , Brune Andreas
Published: August 2007

The key role of free hydrogen in the digestion of lignocellulose by wood-feeding lower termites and their symbiotic gut microbiota has been conceptually outlined in the past decades but remains to be quantitatively analyzed in situ. Using Reticulitermes santonensis, Zootermopsis nevadensis and Cryptotermes secundus, we determined metabolite fluxes involved in hydrogen turnover and the resulting distribution of H2 in the microliter-sized gut. High-resolution hydrogen microsensor profiles revealed pronounced differences in hydrogen accumulation among the species (from <1 kPa to the saturation level). However, flux measurements indicated that the hydrogen pool was rapidly turned over in all termites, irrespective of the degree of accumulation. Microinjection of radiotracers into intact guts confirmed that reductive acetogenesis from CO2 dominated hydrogen consumption, whereas methanogenesis played only a minor role. Only negligible amounts of H2 were lost by emission, documenting an overall equilibrium between hydrogen production and consumption within the gut. Mathematical modeling revealed that production dominates in the gut lumen and consumption in the gut periphery for R. santonensis and Z. nevadensis, explaining the large accumulation of H2 in these termites, whereas the moderate hydrogen accumulation in C. secundus indicated a more balanced radial distribution of the two processes. Daily hydrogen turnover rates were 9–33 m3 H2 per m3 hindgut volume, corresponding to 22–26% of the respiratory activity of the termites. This makes H2 the central free intermediate during lignocellulose degradation and the termite gut—with its high rates of reductive acetogenesis—the smallest and most efficient natural bioreactor currently known.
Dielectric response of one-dimensional polar chains
Authors: Matyushov Dmitry V.
Published: August 2007

We propose a theory for the dielectric constant of materials made of parallel infinite one-dimensional chains of dipoles. Each dipole is allowed to rotate in three dimensions. Monte Carlo simulations show that the Kirkwood factor of the chain grows with increasing dipole moment much faster than in the case of three-dimensional polar fluids. With increasing dipole moment or cooling the one-dimensional chain undergoes a continuous order-disorder transition to the ferroelectric phase, in which the dielectric constant is limited by the size of ferroelectric domains along the chain.
On the geometric quantization of twisted Poisson manifolds
Authors: Petalidou Fani
Published: August 2007

We study the geometric quantization process for twisted Poisson manifolds. First, we introduce the notion of Lichnerowicz-twisted Poisson cohomology for twisted Poisson manifolds and we use it in order to characterize their prequantization bundles and to establish their prequantization condition. Next, we introduce a polarization and we discuss the quantization problem. In each step, several examples are presented.
Relativistic effects and rigorous limits for discrete- and continuous-time quantum walks
Authors: Strauch Frederick W.
Published: August 2007

The mathematical relationship between the discrete-time and continuous-time quantum walks and the one-dimensional Dirac equation is explored by studying a class of solutions for each, expressed in terms of the generalized, regular, and modified Bessel functions, respectively. Rigorous limits connecting these solutions are established. In addition, new analytical and numerical results are presented for quantum walks and the Dirac equation, including entanglement, relativistic localization and wave packet spreading, and normal and anomalous Zitterbewegung.
Apparatus for studies of high-temperature chemical reactions in single particle systems
Authors: Andrzejak Timothy A. , Shafirovich Evgeny , Taylor David G. , Varma Arvind
Published: August 2007

We report a compact microgravity flight apparatus for characterization of high-temperature chemical reactions in single particle systems. The apparatus employs an infrared CO2 laser to ignite 1–5mm samples while video images, thermocouple measurements, laser on/off status, and XYZ accelerometer signals are synchronously recorded. Different operating modes permit preignition quenching, ignition, and combustion experiments to be performed. The apparatus was successfully utilized during microgravity experiments on board NASA research aircraft.
Effect of multiquantum barriers on performance of InGaN∕GaN multiple-quantum-well light-emitting diodes
Authors: Nee Tzer-En , Wang Jen-Cheng , Shen Hui-Tang , Wu Ya-Fen
Published: August 2007

In this paper we demonstrate that the improvement in the emission intensity afforded by the introduction of multiquantum barrier (MQB) structures in an InGaN∕GaN multiple-quantum-well (MQW) light-emitting diode (LED) is attributable to increased excitation cross sections. Over the temperature range from 300to20K, the excitation cross sections of the MQW emissions possessing MQB structures were between 9.6×10−12 and 5.3×10−15cm2, while those possessing GaN barriers were between 8.1×10−12 and 4.5×10−15cm2. We found, however, that the figure of merit for the LED light output was the capture fraction of the cross section; we observed that the dependence of the optical intensity on the temperature coincided with the evolution of the capture fraction. This analysis permitted us to assign the capture cross-section ratios at room temperature for the MQWs with MQBs and with GaN barriers as 0.46 and 0.35. Furthermore, the MQW system possessing well-designed MQB structures not only exhibited the thermally insensitive luminescence but also inhibited energetic carrier overflow.
Type-I optical emissions in Ge∕Si quantum dots
Authors: Gomes P. F. , Iikawa F , Cerdeira F. , Larsson M. , Elfving A. , Hansson G. V. , Ni W.-X. , Holtz P.-O.
Published: August 2007

The authors studied the optical emission of Ge∕Si quantum dots under externally applied biaxial stress using samples grown with different temperatures varying from 430to700°C. The optical emission energy of samples grown at low temperatures is rather insensitive to the applied external stress, consistent with the type-II band alignment. However, for samples grown at high temperatures we observed a large blueshift, which suggests type-I alignment. The result implies that recombination strength can be controlled by the growth temperature, which can be useful for optical device applications.
Effects of gas temperature and electron temperature on species concentration of air plasmas
Authors: Lu XinPei
Published: August 2007

The applications of atmospheric pressure air plasma, such as absorption and reflection of electromagnetic radiation, require an electron density of 1012cm−3 or higher. To achieve the required electron density, the electron temperature needs to reach certain level for a given gas temperature. In this manuscript, to obtain an electron density of 1012cm−3 in one atmospheric pressure air, the required electron temperatures are studied for the given gas temperatures from 500to2000K. It is found that the required electron temperatures decrease dramatically from 15310to11750K when the gas temperature increases from 500to1000K, but further increase the gas temperature to 2000K; the electron temperature of 11315K is still needed to achieve an electron density of 1012cm−3.