bluuebunny/crossref_metadata_2025 huggingface dataset:
A Dual Mass Flux Framework for Boundary Layer Convection. Part I: Transport
Authors: Neggers Roel A. J. , Köhler Martin , Beljaars Anton C. M.
Published: October 2008

This study considers the question of what is the least complex bulk mass flux framework that can still conceptually reproduce the smoothly varying coupling between the shallow convective cloud layer and the subcloud mixed layer. To this end, the model complexity of the classic single bulk mass flux scheme is enhanced. Inspired by recent large-eddy simulation results, the authors argue that two relatively minor but key conceptual modifications are already sufficient to achieve this goal: (i) retaining a dry transporting updraft in the moist limit and (ii) applying continuous updraft area partitioning to this dual mass flux (DualM) framework. The dry updraft represents all internal mixed layer updrafts that terminate near the mixed layer top, whereas the moist updraft represents all updrafts that condense and rise out of the mixed layer as buoyant cumulus clouds. The continuous area partitioning between the dry and moist updraft is a function of moist convective inhibition above the mixed layer top. Updraft initialization is a function of the updraft area fraction and is therefore consistent with the updraft definition. It is argued that the model complexity thus enhanced is sufficient to allow reproduction of various phenomena involved in the cloud–subcloud coupling, namely (i) dry countergradient transport within the mixed layer that is independent of the moist updraft, (ii) soft triggering of moist convective flux throughout the boundary layer, and (iii) a smooth response to smoothly varying forcings, including the reproduction of gradual transitions to and from shallow cumulus convection.

The DualM framework is evaluated by implementing in the Eddy Diffusivity Mass Flux (EDMF) boundary layer scheme of the ECMWF’s Integrated Forecasting System. Single column model experiments are evaluated against large-eddy simulation results for a range of different cases that span a broad parameter space of cloud–subcloud coupling intensities. The results illustrate that also in numerical practice the DualM framework can reproduce gradual transitions to and from shallow cumulus convection. Model behavior is further explored through experiments in which model complexity is purposely reduced, thus mimicking a single bulk updraft setup. This gives more insight into the new model-internal interactions and explains the obtained case results.
A Dual Mass Flux Framework for Boundary Layer Convection. Part II: Clouds
Authors: Neggers Roel A. J.
Published: October 2008

This paper presents the extension of the eddy diffusivity mass flux (EDMF) framework for turbulent transport into the statistical modeling of boundary layer clouds. The advection–diffusion decomposition that defines EDMF is projected onto the turbulent distribution as used in the statistical cloud model. Each EDMF component is thus assigned its own independent probability density function (PDF), resulting in an updraft PDF and a diffusive PDF. This double PDF system is configured and integrated in conserved variable space, with the position and orientation of each PDF determined by its unique nature. The parameterization of the associated updraft/diffusion decomposition of variance introduces close ties to the transport scheme; whereas the grid box mean variance is reconstructed using a prognostic variance budget, the variance of the updraft component is parameterized as a function of the spread among various resolved model updrafts. Individual model components and the scheme as a whole are evaluated in detail against large-eddy simulations of a number of prototype subtropical trade wind cases. The results show that various structures in cloud fraction, condensate, and variance are reproduced. The diffusive PDF acts to represent stratiform clouds; the advective PDF represents cumuliform clouds in conditionally unstable layers. This allows representation of complex scenarios in which both cloud forms occur, such as the transitional trade wind regime featuring cumulus rising into stratocumulus.
Error Structure and Atmospheric Temperature Trends in Observations from the Microwave Sounding Unit
Authors: Zou Cheng-Zhi , Gao Mei , Goldberg Mitchell D.
Published: October 2008

The Microwave Sounding Unit (MSU) onboard the National Oceanic and Atmospheric Administration polar-orbiting satellites measures the atmospheric temperature from the surface to the lower stratosphere under all weather conditions, excluding precipitation. Although designed primarily for monitoring weather processes, the MSU observations have been extensively used for detecting climate trends, and calibration errors are a major source of uncertainty. To reduce this uncertainty, an intercalibration method based on the simultaneous nadir overpass (SNO) matchups for the MSU instruments on satellites NOAA-10, -11, -12, and -14 was developed. Due to orbital geometry, the SNO matchups are confined to the polar regions, where the brightness temperature range is slightly smaller than the global range. Nevertheless, the resulting calibration coefficients are applied globally to the entire life cycle of an MSU satellite.

Such intercalibration reduces intersatellite biases by an order of magnitude compared to prelaunch calibration and, thus, results in well-merged time series for the MSU channels 2, 3, and 4, which respectively represent the deep layer temperature of the midtroposphere (T2), tropopause (T3), and lower stratosphere (T4). Focusing on the global atmosphere over ocean surfaces, trends for the SNO-calibrated T2, T3, and T4 are, respectively, 0.21 ± 0.07, 0.08 ± 0.08, and −0.38 ± 0.27 K decade−1 from 1987 to 2006. These trends are independent of the number of limb-corrected footprints used in the dataset, and trend differences are marginal for varying bias correction techniques for merging the overlapping satellites on top of the SNO calibration.

The spatial pattern of the trends reveals the tropical midtroposphere to have warmed at a rate of 0.28 ± 0.19 K decade−1, while the Arctic atmosphere warmed 2 to 3 times faster than the global average. The troposphere and lower stratosphere, however, cooled across the southern Indian and Atlantic Oceans adjacent to the Antarctic continent. To remove the stratospheric cooling effect in T2, channel trends from T2 and T3 (T23) and T2 and T4 (T24) were combined. The trend patterns for T23 and T24 are in close agreement, suggesting internal consistencies for the trend patterns of the three channels.
Forced and Internal Twentieth-Century SST Trends in the North Atlantic*
Authors: Ting Mingfang , Kushnir Yochanan , Seager Richard , Li Cuihua
Published: October 2008

In recent years, two alarming trends in North Atlantic climate have been noted: an increase in the intensity and frequency of Atlantic hurricanes and a rapid decrease in Greenland ice sheet volume. Both of these phenomena occurred while a significant warming took place in North Atlantic sea surface temperatures (SSTs), thus sparking a debate on whether the warming is a consequence of natural climate variations, anthropogenic forcing, or both; and if both, what their relative roles are. Here models and observations are used to detect and attribute long-term (multidecadal) twentieth-century North Atlantic (NA) SST changes to their anthropogenic and natural causes. A suite of Intergovernmental Panel on Climate Change (IPCC) twentieth-century (C20C) coupled model simulations with multiple ensemble members and a signal-to-noise maximizing empirical orthogonal function analysis are used to identify a model-based estimate of the forced, anthropogenic component in NA SST variability. Comparing the results to observations, it is argued that the long-term, observed, North Atlantic basin-averaged SSTs combine a forced global warming trend with a distinct, local multidecadal “oscillation” that is outside of the range of the model-simulated, forced component and most likely arose from internal variability. This internal variability produced a cold interval between 1900 and 1930, followed by 30 yr of relative warmth and another cold phase from 1960 to 1990, and a warming since then. This natural variation, referred to previously as the Atlantic Multidecadal Oscillation (AMO), thus played a significant role in the twentieth-century NA SST variability and should be considered in future, near-term climate projections as a mechanism that, depending on its behavior, can act either constructively or destructively with the region’s response to anthropogenic influence, temporarily amplifying or mitigating regional climate change.
Mutual Action Between MMCS Structure and Projectile After Ballistic Impact
Authors: Karamiş M. Baki , Cerit A. Alper , Nair Fehmi
Published: October 2008

The interaction between a projectile and metal—matrix composites (MMCs) was investigated in terms of macro cracking, petalling and particularly grain deformation of a matrix alloy at the hole section caused by the projectile at high velocity impact.

Metal matrix composites were manufactured by squeeze casting using Al alloys reinforced with Al 2O3 or SiC. Additionally, laminated composites with SiC particles and back side supported by Kevlar 49® were manufactured and their ballistic behavior tested. The composite and unreinforced Al alloy targets were subjected to ballistic impact with an armor piercing projectile of 7.62mm caliber at a speed in the range of 770—800 m/s. The macro examination focused on cracking and petalling after impact. The investigation of grain deformations of matrix alloy was conducted by light microscopy in the hole section created by the projectile.

The hole section created by the projectile had different profiles. Around the hole sections, different grain deformation rates in different directions took place for reinforced and unreinforced Al alloys.

Strong friction took place between the projectile and hole surface and the velocity of the projectile was decreased suddenly in the hole as it met the reinforcement particles in the composite body. These led to deformations of the projectile surface and grain surrounding the reinforcement. In the case of laminate composites, the laminates were fractured and deformed in the direction of projectile movement.
Exploratory study of approvals and disapprovals in Australian instrumental music teaching
Authors: Zhukov Katie
Published: October 2008

Research on the use of approvals/disapprovals in classroom teaching has highlighted praise as more effective than criticism, specific evaluation more valuable than general, and gender differences. This study investigated the use of positive/negative and specific/general evaluation and gender effects in instrumental music lessons in higher education. The participants were 12 teachers and 24 students from five Australian tertiary institutions. Greater use of approvals than disapprovals was found in most lessons. The teachers were more specific when criticizing their students than when praising them. The female teachers were slightly more positive than the male teachers, but the male teachers were more specific in their appraisals of the students' playing. The female students received more teacher praise than the male students. Results support previous research and provide new evidence into the use of approvals and disapprovals in instrumental music lessons in higher education. The implications for teaching practice include greater use of specific praise and sensitivity to gender biases.
Nurturing the careers of Australia's future composers
Authors: Watson Amanda , Forrest David
Published: October 2008

In 1994, the Australian Society for Music Education (ASME) initiated two related projects supporting and acknowledging composition in schools and offering the opportunity for secondary school-aged students to work with prominent Australian composers. These were the Young Composers' Project and the Composer-in-Residence Project. Both projects were planned in conjunction with the biennial ASME National Conference, in association with the Australian Music Centre and initially the Australia Council for the Arts. The context of this article is set with an overview of the teaching of composition in the compulsory and post-compulsory years of schooling in Australia, giving contrasting examples of a specific syllabus and a generic framework. Organizations in Australia that provide composition opportunities for students are identified and acknowledged. The ASME Young Composers' Project and the Composer-in-Residence Project are presented to illustrate venture-developed projects that are promoted by a professional teaching association to nurture school-age student composers and the teaching of composition in schools. The experiences of some of the students who have participated in the projects are presented. Their comments mainly focus on the opportunity that is provided by the Young Composers' Project to work with composers and professional ensembles, and the opportunity to meet members of their peer group with like interests.
Metaphors, intercultural perspective and music teacher training at the University of the Basque Country
Authors: Ibarretxe Txakartegi Gotzon , Díaz Gómez Maravillas
Published: October 2008

The purpose of this article was to identify the interactions between students' cultural background and the conditions of teaching and learning at the University of the Basque Country. A group of second- and third-year students was selected because of their special involvement in musical activities, i.e., singing in a choir, singing and playing traditional and pop music. The students experienced these musical activities in current contexts of cultural diversity. For example, they used them for integration in their own cultural contexts, and also in their practical teacher training in schools. The results suggested that an intercultural perspective could have a positive impact on improving the quality of music education. In addition, this was an important area where students and teachers needed training.
Exploring the music festival as a music educational project
Authors: Karlsen Sidsel , Brändström Sture
Published: October 2008

The purpose of this article was to explore the music festival as a music educational project by means of results drawn from a case study investigating one particular festival's impact on identity development, both for the individual member of the audience (musical identity) and for the local society (local identity). The theoretical framework was taken from theories of modernity, dealing with identity as a reflexive project, created and maintained by self-narratives. The study combined a survey among the festival audience with observations of festival events. The results showed that the festival mediated stories, myths, beliefs and values connected to music and that there was a contrast between the festival staff encouraging the development and the audience preferring the maintenance of musical identities. The festival also created different social rooms for musical activity. These features are discussed in a music educational perspective. Implications are also drawn for music educational practice and research.
Traditional Chinese instrumental music: importing diversity into Midwestern America
Authors: Prescott John , Sun Li  , Meng Lei
Published: October 2008

Because of the lack of diversity in many communities in the USA, there is both a need and an opportunity to import diversity through the arts into these communities through special programs. This article describes one such program undertaken by a US university making use of a pre-existing student/faculty exchange program with a university in the People's Republic of China. There is a brief explanation of how the students and teachers of a course in Traditional Instrumental Music of China were recruited over the period of a year and how the following instruments were chosen: guzheng, pipa, huapengu, dizi, xiao, hulusi, bawu, sheng and suona. Details are given regarding the design and implementation of the course over a three-week period. Selected musical examples are provided to illustrate the progressive nature of the instruction along with the level of facility acquired at the end of the course. Results of the course and plans for the future are also provided.
The Social Sciences in Australia: an Unrequited Instrumentalism
Authors: Macintyre Stuart
Published: October 2008

Australian universities expanded rapidly in the period after the Second World War, assisted by the national government and with a clear understanding that they would serve national purposes. Social scientists sought to participate in the enhanced opportunities for research by pressing their relevance to the nation-building project. At the same time they sought academic recognition as research disciplines by stressing the objective and authoritative character of their knowledge. This article explores the way these strategies were pursued in Australia and the United States, and suggests their consequences. The institutionalization of the social sciences in the university is contrasted with the oppositional social science practised in the labour movement's independent working-class education in the early part of the 20th century, and it is argued that the expectations created by state support of research in the social sciences — and the policies imposed to serve them — are ill founded.
Equality and Exclusion: the Racial Constitution of Colonial Liberalism
Authors: Lake Marilyn
Published: October 2008

In his path-breaking study, A Colonial Liberalism: The Lost World of Three Victorian Visionaries (1991), Stuart Macintyre makes a case for the distinctiveness of colonial liberalism and its local habitat, with liberals' insistence on the principle of political equality and the democratic right of self-government. Macintyre's three visionaries — Higinbotham, Pearson and Syme — were also leading crusaders against Chinese immigration, which peaked in Victoria in the 1850s, the decade in which self-government and manhood suffrage were introduced. The local habitat wore a racial aspect. In this essay I suggest that it was precisely the democratic ideal of equality, espoused in the context of Chinese immigration and colonial nation-building, that led to the insistence on racial exclusion. Colonial liberals called for racial exclusion because of, not in spite of, their commitment to democracy. The apparent paradox of a policy of exclusion promoted in the name of equality was, I suggest, definitive of the project of colonial liberalism.
Properties of GF/PP Commingled Yarn Composites
Authors: Ogale Vinayak , Alagirusamy R.
Published: October 2008

The influence of glass-fiber (GF)/polypropylene (PP) commingled yarn structure on the impregnation quality of laminates is investigated by characterizing the microstructure and mechanical properties of the laminates. For this study, the degree of interlacing of the commingled yarns is taken as a measure of the structure of commingled yarns. Properties of laminates made by compression molding of commingled yarns are compared with those of laminates made with two other methods of composite manufacturing: film stacking and side-by-side (SBS) winding of glass roving and PP yarns. The results show that the degree of interlacing has a significant influence on the void content, fiber impregnation, and tensile behavior of composites made from commingled yarns. Laminates made from SBS and film stacking show more voids and dry fibers than those made from commingled yarns for the same consolidation conditions.
Preparation and Properties of M40 Carbon Fiber-Reinforced Thermoplastic Polyimide Composites
Authors: Lu Yun-Hua , Zhan Mao-Sheng , Zheng Wen-Hai
Published: October 2008

A series of M40 high modulus carbon fiber-reinforced polyimide (CFRPI) composites are prepared by laminating premolding PI films with unidirectional CF layers. After the imidization processing of premolding PI films is estimated, the effect of CF volume fraction, processing conditions, and PI molecular structure on the properties of CFRPI composites is studied in detail. In addition, SiO2 nanoparticles are added as fillers to the premolding PI films at varying concentrations. The effect of the nanoparticles on the properties of CFRPI composites is also investigated. The surface characteristics of M40 CF are measured by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The thermal and mechanical properties of CFRPI composites are measured by dynamic mechanical thermal analysis, SANS testing machine, scanning electron microscopy, and other techniques. The experimental results show that the properties of CFRPI composites are mainly affected by the premolding PI film and molding conditions. The change of CF volume fraction from 55 to 65% has little effect on the mechanical properties of the CFRPI composites. In addition, flexible PI as a CF sizing improves the interlaminar shear strength, flexural strength, and flexural modulus of CFRPI composites, and the incorporation of SiO2 nanoparticles further improves the properties of CFRPI composites.
Impact of Nd-YAG Laser Drilling on the Fatigue Characteristics of APC-2A/AS4 Thermoplastic Composite Material
Authors: Young Trevor M.
Published: October 2008

Both carbon fiber thermoset and thermoplastic materials can be drilled using a laser. This, however, results in significant damage to the material, but the extent to which this would reduce the fatigue life was not known. Studies have been conducted to evaluate this for an aerospace application, which required a light-weight, but perforated, skin panel through which air could be sucked. The objective has been to determine the impact on the fatigue life of quasi-isotropic APC-2A/AS4 due to Nd-YAG laser-drilled holes (~120 μm diameter, spaced ~500 μm apart). Static tensile tests indicate a 29% reduction in strength. The maximum stress versus cycles to failure (S—N) relationship is represented by a power law function: S=KNm. The laser drilling has been seen to reduce the value of K (coefficient of fatigue strength), but the value of m (fatigue strength degradation exponent), which was determined from nonperforated specimens, was unchanged.
Revolution and Diavolution: What Is the Difference?
Authors: Mubi Brighenti Andrea
Published: October 2008

Whereas revolution has often been viewed as contrary to organization, it in fact requires the overcoming of a present organization in the promise of achieving another superior organization. The article conducts a theoretical, rather than historical, reflection on the interplay among three concepts: organization, revolution, and diavolution. By exploring the modernist conception of revolution, the idea is advanced that the relationship can be framed as follows: organization is the katéchon of revolution, whereas revolution is the éschaton of organization. The last part of the article introduces and discusses the concept of diavolution as an attempt to overcome the dichotomy between the subjectivist and the structuralist view both at the theoretical and the practical level. Diavolution is a style of inhabiting organizations that differs from the revolutionary one; a style of resistance that, although much more elusive and difficult to capture, may prove to be at the same time more human.
Love and Revolution
Authors: Chabot Sean
Published: October 2008

Critical sociologists have long recognized the intersections between love and revolution. For the most part, however, our understanding of love and its relevance for revolution remains vague. My article seeks to remedy this limitation. It starts by sketching the social and personal contexts of alienation, indicating that in today's capitalist world genuine love is revolutionary in itself. It then specifies what love means, what types of love exist, and what revolutionary love implies in theory and practice. The next section introduces the political cultures of loving revolution concept and applies it to the Indian independence movement led by Gandhi. The conclusion discusses how potential revolutionaries might benefit from my interpretation of love and revolution.
Space Environment Exposure of Polymer Films on the Materials International Space Station Experiment: Results from MISSE 1 and MISSE 2
Authors: Dever Joyce A. , Miller Sharon K. , Sechkar Edward A. , Wittberg Thomas N.
Published: October 2008

A total of thirty-one samples were included in the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) Polymer Film Thermal Control (PFTC) and Gossamer Materials experiments, which were exposed to the low Earth orbit environment for nearly 4 years on the exterior of the International Space Station (ISS) as part of the Materials International Space Station Experiment (MISSE 1 and MISSE 2). This paper describes objectives, materials, and characterizations for the MISSE 1 and MISSE 2 GRC PFTC and Gossamer Materials samples. Samples included films of polyimides, fluorinated polyimides, and Teflon® fluorinated ethylene propylene (FEP) with and without second-surface metalized layers and/or surface coatings. Films of polyphenylene benzobisoxazole (PBO) and a polyarylene ether benzimidazole (TOR-LM TM) were also included. Polymer film samples were examined post-flight for changes in mechanical and optical properties. The environment in which the samples were located was characterized through analysis of sapphire contamination witness samples and samples dedicated to atomic oxygen (AO) erosion measurements. Results of the analyses of the PFTC and Gossamer Materials experiments are discussed.
MISSE 2 PEACE Polymers Atomic Oxygen Erosion Experiment on the International Space Station
Authors: De Groh Kim K. , Banks Bruce A. , Mccarthy Catherine E. , Rucker Rochelle N. , Roberts Lily M. , Berger Lauren A.
Published: October 2008

Forty-one different polymer samples, collectively called the Polymer Erosion and Contamination Experiment (PEACE) Polymers, were exposed to the low Earth orbit (LEO) environment on the exterior of the International Space Station (ISS) for nearly 4 years as part of Materials International Space Station Experiment 2 (MISSE 2). The objective of the PEACE Polymers experiment was to determine the atomic oxygen erosion yield of a wide variety of polymeric materials after long-term exposure to the space environment. The polymers range from those commonly used for spacecraft applications, such as Teflon ® FEP, to more recently developed polymers, such as high temperature polyimide PMR (polymerization of monomer reactants). Additional polymers were included to explore erosion yield dependence upon chemical composition. The MISSE PEACE Polymers experiment was flown in MISSE Passive Experiment Carrier 2 (PEC 2), tray 1, attached to the exterior of the ISS Quest Airlock. It was exposed to atomic oxygen along with solar and charged particle radiation. MISSE 2 was successfully retrieved during a space walk on July 30, 2005 during Discovery's STS-114 Return to Flight mission. Details on the specific polymers flown, flight sample fabrication, pre-flight and post-flight characterization techniques, and atomic oxygen fluence calculations are discussed along with a summary of the atomic oxygen erosion yield results. The MISSE 2 PEACE Polymers experiment is unique because it has the widest variety of polymers flown in LEO for a long duration and was exposed to an unusually clean LEO spacecraft environment. This experiment provides extremely valuable erosion yield data for spacecraft design purposes.
Degradation of Hubble Space Telescope Aluminized-Teflon Bi-Stem Thermal Shields
Authors: De Groh Kim K. , Snyder Aaron , Finlay Katherine A.
Published: October 2008

A section of retrieved Hubble Space Telescope (HST) bi-stem thermal shields (BSTS), which experienced 8.25 years of space exposure, was analyzed for space environmental durability. The shields were comprised of 2 mil (0.051 mm) aluminized-Teflon® fluorinated ethylene propylene (Al-FEP) rings fused together into a circular bellows shape. As the circular thermal shields had solar, anti-solar and solar-grazing surfaces and were exposed to the space environment for a long duration, it provided a unique opportunity to study solar effects on the environmental degradation of Al-FEP, a commonly used spacecraft thermal control material. Therefore, the objective of this research was to characterize the degradation of retrieved HST BSTS Al-FEP with particular emphasis on solar effects. Data obtained included tensile properties, density (as-retrieved and after 200 3C heating), solar absorptance, and surface morphology and chemistry. The solar-facing surfaces of the thermal shields were found to be extremely embrittled and contained numerous through-thickness cracks. Tensile testing verified that near solar-facing surfaces lost their mechanical strength and elasticity, whereas the anti-solar-facing surfaces maintained their ductility. The density of the as-retrieved BSTS insulation was similar to pristine FEP. Heating at 200 3C resulted in significant increases in density for the solar-facing BSTS indicating chain scission damage, consistent with the loss of mechanical strength and elongation. The solar absorptance of the solar-grazing and the anti-solar-facing surfaces were found to be similar to pristine BSTS, whereas the solar-facing surfaces were found to have significantly increased solar absorptance. Both solar- and anti-solar-facing surfaces were microscopically textured from sweeping atomic oxygen erosion with the solar-facing surface appearing to have a more pronounced texture in spite of being exposed to a lower atomic oxygen fluence indicating a possible solar/atomic oxygen synergistic effect. These results provide valuable information on space environmental degradation of Al-FEP, particularly with respect to solar radiation effects on embrittlement.
POSS-Polyimide Nanocomposite Films: Simulated Hypervelocity Space Debris and Atomic Oxygen Effects
Authors: Verker R. , Grossman E. , Gouzman I. , Eliaz N.
Published: October 2008

The combined effect of hypervelocity space debris impact and atomic oxygen (AO) attack on the degradation of reinforced polyhedral oligomeric silsesquioxanes (POSS)-polyimide films was studied. A laser-driven flyer (LDF) system was used to accelerate aluminum flyers to impact velocities of up to 3 km s -1. The impacted films were exposed to an RF-plasma source, which was used to simulate the effect of AO in the low Earth orbit. Scanning electron microscopy (SEM) was used to characterize the fracture morphology. The extent of damage in POSS-polyimide impacted films was found to be much smaller compared to POSS-free films, insinuating on a toughening mechanism developed due to POSS incorporation. When exposed to air RF-plasma, the impacted POSS-free film revealed a synergistic effect associated with a large increase in the erosion rate while impacted POSS-containing samples showed improved erosion resistance. The increased erosion rate of the impacted POSS-free film is explained by formation of residual stresses that affect the oxidation mainly by increasing the diffusivity of oxygen.
Space Charge Detection in Kapton® and PTFE Polymer Films by the Open Pulsed Electro-Acoustic Method
Authors: Perrin C. , Griseri V. , Laurent CH , Fukunaga K. , Maeno T. , Levy L. , Payan D. , Schwander D.
Published: October 2008

Kapton® and poly(tetrafluoroethylene) (PTFE) are insulating materials that are commonly used in a space environment, notably in applications for the thermal regulation of satellites. When the satellite is in a geostationary orbit these materials are subjected to a flux of charged particles trapped in the radiation belts, and particularly to energetic electrons. They can accumulate charges due to their dielectric properties, which generate localized increases of the electric field in the material bulk that can lead to an electrostatic discharge. This phenomenon could involve serious damage to the satellite structure or performance. A behavioral study of Kapton® and PTFE materials under electronic irradiation could be helpful to understand the charge transport in the body of the material and allow a discharge control strategy to be developed. In the present study, two different measurement tools have been combined — classical surface potential measurements and Pulse Electro-Acoustic (PEA) measurements — which give information on the charge distribution in the bulk. The latter method has been further adapted for use in a vacuum during the sample irradiation and measurements under various conditions have been performed. Two measurement configurations for the irradiated sample have been studied. In the first configuration, the irradiated sample surface is grounded during the whole irradiation period. In contrast, the second configuration is one in which the irradiated sample surface is left at floating potential. Measurements made with the PEA method in both the configurations will be compared in this article, in order to determine the main physical mechanisms of charge transport occurring during the bulk sample irradiation for each irradiation configuration.
Lateglacial and Holocene vegetation dynamics in the Aegean region: an integrated view based on pollen data from marine and terrestrial archives
Authors: Kotthoff Ulrich , Müller Ulrich C. , Pross Jörg , Schmiedl Gerhard , Lawson Ian T. , van de Schootbrugge Bas , Schulz Hartmut
Published: October 2008

To elucidate the vegetation dynamics in the Aegean region during the last 20 kyr, we have studied terrestrial palynomorphs in marine core GeoTü SL152 (Mount Athos Basin, northern Aegean Sea) at centennial-scale (125 to 300 yr) resolution. The robust chronology of the core allows us to reliably date signals of short-term vegetation change in the Aegean region. For the Pleniglacial interval until ~14.6 kyr BP, our data document steppe vegetation, suggesting dry climatic conditions in the borderlands of the Aegean Sea. Subaerially exposed parts of the shelf were probably colonized by Pinus-dominated vegetation until shelf areas were flooded during Lateglacial sea-level rise. The final, rapid decrease of Pinus pollen percentages between ~14 and ~13 kyr BP appears to be connected to meltwater pulse MWP-1A. The Lateglacial interstadial complex (ie, Meiendorf, Bølling and Allerød) is characterized by the spread of oak trees, but also by the continuous presence of steppe elements, indicating only slightly increased humidity. The Younger Dryas chronozone was the driest interval of the past 20 kyr. Insufficient humidity was most likely also responsible for the ~2.0 kyr delay in Holocene reforestation in the Aegean region relative to western Greece. During the Holocene, the vegetation was repeatedly affected by centennial-scale episodes of reduced moisture availability. Radiocarbon-based age models of previously published pollen records imply strong discrepancies in vegetation development in the Aegean region, but there are reasons to doubt the accuracy of these age models. Here we use the well-dated pollen record from marine core SL152 and biostratigraphic correlation to propose revised chronologies for several published terrestrial pollen records. This re-assessment yields a spatiotemporally consistent pattern of vegetation dynamics in the borderlands of the Aegean Sea.
Instrumental period rainfall series of the Indian region (AD 1813—2005): revised reconstruction, update and analysis
Authors: Sontakke N.A. , Singh Nityanand , Singh H.N.
Published: October 2008

Sontakke and Singh ( The Holocene 6, 315—31, 1996) developed instrumental period summer monsoon (June—September total) rainfall series (1813—1995) for six homogeneous zones and all of India using 306 raingauge stations. This reconstruction has been revised and updated. Besides reconstructing backward and updating to 2005 the longest possible summer monsoon rainfall series (1813—2005), post-monsoon (October— December total) and annual rainfall series have also been developed for seven homogeneous zones: North Mountainous India (NMI), Northwest India (NWI), North Central India (NCI), Northeast India (NEI), West Peninsular India (WPI), East Peninsular India (EPI), South Peninsular India (SPI), and the whole country using data from 316 well-spread stations. The different series are reported here. The underlying mechanism of the possible cause of the recent decreasing trend in monsoon rainfall and increasing trend in post-monsoon rainfall is described.
Spruce trees from a melting ice patch: evidence for Holocene climatic change in the Colorado Rocky Mountains, USA
Authors: Benedict James B. , Benedict Robert J. , Lee Craig M. , Staley Dennis M.
Published: October 2008

In September, 2006, we found the remains of timber-sized spruce trees ( Picea engelmannii) on the floors of melting ice patches at altitudes of 3465—3480 m in the Mummy Range of north-central Colorado. The ice patches occupy northeast-facing recesses in which windblown snow, scoured from a tundra upland to the southwest, accumulates deeply. We hypothesize that the upland was timbered during the early to middle Holocene. Dense forest vegetation intercepted snow, preventing it from blowing to the recesses, and allowing trees to become established there. Neoglacial cooling led to gradual deforestation of the upland, renewed transport and deposition of snow by wind, and death of the ice-patch trees. Radiocarbon dates show that the trees died between 3860 ± 15 and 3780 ± 20 14C yr BP ( c. 4200 cal. yr BP). The trunks show decay similar to that of historic log structures built above timberline during the late nineteenth and early twentieth centuries, suggesting that they have been protected by ice for all but a small portion of the past 4200 years. A series of warm summers and dry winters led to their recent emergence. The study illustrates the importance of monitoring glaciers and ice patches for floral, faunal and archaeological remains whenever severe melting occurs.
Dogs, humans and island ecosystems: the distribution, antiquity and ecology of domestic dogs (Canis familiaris) on California's Channel Islands, USA
Authors: Rick Torben C. , Walker Phillip L. , Willis Lauren M. , Noah Anna C. , Erlandson Jon M. , Vellanoweth René L. , Braje Todd J. , Kennett Douglas J.
Published: October 2008

Archaeologists have made significant contributions to our understanding of ancient island environments, including the timing and implications of the introduction of non-native animals (pigs, chickens, rats, etc.) by humans. Here, we focus on the historical ecology and biogeography of domestic dogs ( Canis familiaris) on California's Channel Islands during the Holocene. Dogs are the only animal known unequivocally to have been introduced by Native Americans to the islands, but relatively little is known about their distribution, antiquity or influence on native island fauna and flora. We identified a minimum of 96 dogs from 42 archaeological sites on six of the eight islands. Dogs were present for at least 6000 years and appear to have increased in abundance through time. Our analysis suggests that dogs, along with humans and island foxes ( Urocyon littoralis), would have had an impact on native animals and ecosystems, especially breeding birds and marine mammals. Dogs and island foxes likely competed with one another for food, however, and the impacts of dogs on island ecosystems may have been reduced by the presence of island foxes and the symbiotic relationship between dogs and humans. Dogs have been removed from all but one of the islands today, eliminating one of the few terrestrial carnivores present for most of the Holocene.
Vegetation changes during the late Pleistocene and Holocene in Lebanon: a pollen record from the Bekaa Valley
Authors: Hajar L. , Khater C. , Cheddadi R.
Published: October 2008

A sediment core retrieved from Quaternary deposits from the Aammiq wetland (Bekaa Valley, Lebanon) provided a pollen record carrying valuable information which allowed reconstruction of past vegetation dynamics in relation to climate change and anthropogenic impacts. Core stratigraphy and microfossil data helped interpret the depositional settings of the sequence. Before c. 12.2 kyr cal. BP, an expansion of cedars ( Cedrus libani) and deciduous oaks ( Quercus cerris-type) is observed. The Younger Dryas is marked by the spread of a Chenopodiaceae steppe and a regression of cedars and deciduous oaks. During the early Holocene, an open oak forest expanded concomitantly with the development of a marsh in the Bekaa Valley. Between c. 6.0 and c. 3.4 kyr cal. BP, major disturbances in the sedimentation process are recorded, leading to some dissimilarities with other palaeobotanical records from the Eastern Mediterranean region. After c. 3.4 kyr cal. BP, the pollen data reveal that agriculture in the Bekaa Valley was mainly oriented towards livestock rearing since there is very little record of cultivated plants. In this regard, the results conflict somewhat with other studies carried out in the Eastern Mediterranean region, where intensive cultures have been observed since the early Holocene. Cultures might have been present in other regions in Lebanon but apparently not in this part of the Bekaa Valley.
Distinguishing sediments from the Yangtze and Yellow Rivers, China: a mineral magnetic approach
Authors: Zhang Weiguo , Xing Yu , Yu Lizhon , Feng Hua , Lu Min
Published: October 2008

The Yellow River and the Yangtze River contribute ~10% of the global fluvial sediment flux to the oceans. Proper characterization of the sediments of the two rivers is critical to the knowledge of their fate in the marginal seas of the west Pacific Ocean. Magnetic measurements have been made on bulk sediments as well as on separated particle size fractions of representative samples from the Yellow and Yangtze River estuaries, with the purpose of providing an efficient means of differentiating both groups of river sediments from each other. We found that on average the Yangtze River estuary sediments have relatively higher ferrimagnetic mineral contents and ferrimagnetic to antiferromagentic ratios compared with the Yellow River estuary sediments. A diagram of Saturated Isothermal Remanent Magnetization (SIRM) versus the demagnetization parameter S−100 can clearly distinguish sediments from the two rivers. Detailed magnetic measurements carried out on particle size fractions provide additional confirmation of magnetic contrasts between the two sets of river sediment samples. These contrasts reflect differences in lithology and weathering regimes in the catchments. To minimize possible biogenic and postdepositional diagenetic overprint in the marine environment, it is recommended that magnetic comparison on the coarser materials (eg, >4 µm) be carried out in addition to bulk measurements. This study shows that the magnetic approach can therefore provide a potentially efficient means of discriminating sediment sources in the Yellow Sea and East China Sea. In view of the rapid variations in sediment load carried by these two rivers in recent years, the present data set also provides a baseline against which possible future variations in sediment composition resulting from catchment changes can be assessed.
There Was a Schlieffen Plan: New Sources on the History of German Military Planning
Authors: Groß Gerhard P.
Published: October 2008

For almost ten years international military historians have been discussing Terence Zuber's thesis of the Schlieffen Plan being just a myth designed by the German general staff after the First World War to cover up the mistakes committed by German generals in that war. This debate, led with particular ferocity in War and History, is based on German files that Zuber was the first to study. The following paper, however, challenges Zuber's theories on the basis of files and maps Zuber failed to consider. It seeks to prove that there was a basic operational-strategic doctrine — the Schlieffen Plan — and Schlieffen's successor stuck unwaveringly to it, although a few operational modifications were made. This doctrine was even implemented by the Wehrmacht in the Second World War, albeit in a modified version.
The Royal Air Force and Close Support, 1918—1940
Authors: Harvey A.D.
Published: October 2008

The traditional account of the Royal Air Force's neglect of close air support in the interwar years, as well as misrepresenting German achievements in this area, overlooks the amount of attention given to the subject in the RAF and the extent to which at least some of the intrinsic problems of close support aviation were appreciated.
Vasopressin and angiotensin receptors of the medial septal area in the control of mean arterial pressure induced by vasopressin
Authors: Pavan de Arruda Camargo Gabriela Maria , Abrão Saad Wilson , de Arruda Camargo Luiz Antônio
Published: October 2008

Introduction. Brain arginine8-vasopressin (AVP), through the V1a- and V2-receptors, is essential for the maintenance of mean arterial pressure (MAP). Central AVP interacts with the components of the renin-angiotensin system, which participate in MAP regulation. This study aimed to determine the effects of V1a-, V2- and V1a/V2-AVP selective antagonists and AT1- and AT2-angiotensin II (Ang II) selective antagonists on the MAP induced by AVP injected into the medial septal area (MSA) of the brain.

Materials and methods. Male Holtzman rats with stainless steel cannulae implanted into the MSA were used in experiments. Direct MAP was recorded in conscious rats.

Results. AVP administration into the MSA caused a prompt and potent pressor response in a dose-dependent fashion. Pretreatment with the V1a- and V2-antagonists reduced, whereas prior injection of the V1a/V2-antagonist induced a decrease in the MAP that remained below the baseline. Both AT1- and AT2-antagonists elicited a decrease, while simultaneous injections of two antagonists were more effective in decreasing the MAP induced by AVP.

Conclusion. These results indicate there is a synergism between the V1a- and V2-AVP and AT1and AT2-Ang II receptors in the MSA in the regulation of MAP.
Inhibition of the renin-angiotensin system: effects on tachycardia-induced early electrical remodelling in rabbit atrium
Authors: Laszlo Roman , Eick Christian , Rueb Norman , Weretka Slawomir , Weig Hans-Joerg , Schreieck Juergen , Bosch Ralph F
Published: October 2008

Introduction. Tachycardia-induced atrial remodelling (as an equivalent to atrial fibrillation) can be influenced by the renin-angiotensin system. Effects of a seven-day enalapril pre-treatment (EPT, 0.16 mg/kg body weight subcutaneously every 24 h) on ionic currents underlying tachycardia-induced early electrical remodelling after 24 h rapid atrial pacing (RAP, 600 beats/min) in rabbit atrium were studied.

Materials and methods. Animals were divided into four groups (n=4 each): control; paced only; enalapril only; and enalapril and paced, respectively. Using patch-clamp technique in whole-cell mode, current densities were measured in isolated atrial myocytes. Results. EPT nearly doubled L-type calcium current (ICa,L, −7.7±0.6 pA/pF [control] vs. f −12.3±1.2 pA/pF [enalapril only]). RAP reduced ICa,L to −3.6±0.7 pA/pF (paced only). Also after EPT, RAP led to a significant downregulation of ICa,L by 39% (−7.5±1.3 pA/pF [paced and enalapril]). RAP decreased transient outward potassium current (Ito, −45%, 51.5±3.9 pA/pF [control] vs. 28.5±4.5 pA/pF [paced only]). EPT did not alter Ito (44.2±8.1 pA/pF [enalapril only]). However, RAP did not affect Ito in enalapril-treated animals and averaged 50.4±9.8 pA/pF (paced and enalapril).

Conclusions. In summary, EPT has several effects on ion channels in rabbit atrium: 1) EPT increases ICa,L current density, but cannot prevent its downregulation due to RAP; 2) EPT has no influence on Ito current density, but can prevent its downregulation due to RAP. Although changes of single ion channels must be interpreted in context of the complex atrial electrophysiology as a whole, our results provide a possible explanation of the in vivo observation that angiotensin-converting enzyme inhibition is mainly beneficial on the early electrical remodelling due to the atrial fibrillation-equivalent RAP.