bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma profiles of progesterone and total oestrogens in buffaloes (Bubalus bubalis) around parturition
Authors: El-Belely M. S. , Zaki K. , Grunert E.
Published: March 2009

Blood samples were collected three times weekly for 21 days before and after calving (day 0) from 29 buffalo cows and 22 buffalo heifers. Plasma concentrations of progesterone and total oestrogens were quantified by validated radioimmunoassays. Ovarian activity and uterine involution were monitored by rectal palpation at the sampling times and extended up to 60 days postpartum. The concentration of plasma progesterone in cows declined from 3·0 ± 0·2 ng/ml (mean ± S.E.) during days 21–17 before calving to 2·1 ± 0·1 ng/ml at day −3, followed by a rapid fall during the last 3 days of gestation, reaching 1·2 ± 0·3 ng/ml at the day of parturition. In heifers, plasma progesterone values increased slightly from 2·9 ± 0·2 ng/ml at days 21–19 before parturition to 3·4 ± 0·3 ng/ml by day −1 and then fell sharply to 2·1 ± 0·1 ng/ml at calving time. During the postpartum period, plasma progesterone decreased gradually and reached baseline values after day 15 postpartum, when the residual corpus luteum of pregnancy had completely regressed in all the animals studied. The plasma concentrations of total oestrogens started to increase at day −15 in cows and day −5 in heifers from below 40 pg/ml to 122·5 ± 51 pg/ml for cows and 100·7 ± 3·4 pg/ml for heifers by day −1. This was followed by a sharp increase to 251·2 ± 17·3 and 240·5 ± 10·1 pg/ml in these animals at the day of calving. Immediately after parturition, total oestrogens dropped abruptly to the lowest values and remained below 30 pg/ml in all cows and heifers until the end of the sampling period. We concluded that female foetuses significantly (P< 0·05) increased the maternal total oestrogens. Moreover, animals having postpartum disorders had significantly higher values for progesterone (P< 0·05) and lower values for total oestrogens (P< 0·01) than those having normal puerperal periods, but the magnitude of this difference varied in samplings between cows and heifers.
Interactions between plots in experiments with the splash-dispersed pathogenRhynchosporium secalison winter barley
Authors: Jenkyn J. F. , Dyke G. V. , Stedman O. J. , Todd A. D.
Published: March 2009

Experiments of balanced design in harvest years 1981 and 1982 were used to measure interactions between plots of winter barley with different amounts of leaf blotch, caused by the splash-dispersed pathogenRhynchosporium secalis. On the appropriate transform scales (logarithms of counts and logits of percentages), the effects of extreme treatments on neighbouring plots were up to 30% of the effects of the same treatments on the plots to which they were applied. Powdery mildew (Erysiphe graminisf.sp.hordei) was commonly least severe in plots with most leaf blotch except soon after fungicide sprays had been applied which, although chosen to decrease leaf blotch, also had short-lived effects on mildew. Consequently, contrasts in mildew between differently treated plots changed sign during the season. The effects of the same treatments on neighbouring plots similarly changed with time but not necessarily in phase with their direct effects. Analyses of the rhynchosporium data that recognized the effects of neighbouring treatments typically had much smaller residual mean squares than analyses that ignored neighbour effects but assumed randomized block designs.

Treatments had mostly small effects on grain yield but these data from two of the experiments showed marked positional variation. Individual plots yields from one of these experiments, testing five treatments, are quoted in the appendix so that they are available to others with an interest in alternative methods, such as nearest-neighbour models, to adjust for local correlations between plots.
Stocking density of cattle and herbage production on Mediterranean grassland
Authors: Seligman N. G. , Gutman M. , Holzer Z. , Meir I. Noy , Baram H.
Published: March 2009

A Mediterranean grassland was grazed with beef cattle at 0·5, 0·67 and 0·83 cows/ha, all the year round for 5 years. Range forage became increasingly scarce during the dry season, especially at high stocking density, and more supplementation was needed to maintain the animals. Herbage consumption was calculated from standard requirements for recorded body weight and performance. Maintenance requirements were multiplied by a grazing activity factor of 1·6.

Mean annual herbage dry matter production was estimated atc.3·06 ± 0·137 t/ha. Most of the variation between years was due to a particularly productive year in 1978. Contrary to expectation, stocking density had a small effect on total herbage production, despite significant differences in animal performance. It appears that herbage production of the seasonally temperate herbaceous range, typical of the basaltic hills in eastern Galilee in Israel, is not limited by total annual rainfall. Alternative limiting factors are nutrient deficiency and restricted rooting zone, or a combination of both.
Effect of topping and irrigation on yield of flue-cured tobacco grown in a Mediterranean environment
Authors: Orphanos P. I. , Metochis C.
Published: March 2009

Topping of tobacco (Nicotiana tabacumL.) plants (removal of the inflorescence) is not practised in Cyprus. Two field experiments were carried out at Akhelia Station, in 1985 and 1986, to test whether topping increased the yield or improved leaf quality of flue-cured tobacco grown under different types of irrigation. In contrast to the results of other studies, topping when the corolla had appeared on half the flowers did not increase yield. Topping when the inflorescence was just clear of the leaves (21 leaves harvested from topped plants v. 32 leaves from untopped plants) increased fresh yield by 7·0% but dry matter yield by 18·0%. The effects of topping were more marked on the leaves reaped at the third and fourth harvests, which constituted 52% of the fresh yield or 60% of the dry matter yield. At these harvests, leaves from topped plants had a lower percentage of midrib material (18·5v.21·0%) than leaves from untopped plants but a higher dry matter content (19·2v.17·2%) and specific leaf weight (80·0v.56·0 g/m2). Leaves of the fourth harvest from topped plants (27% of the total fresh yield) contained appreciably more nicotine (1·34%) than leaves from untopped plants (0·40%) but had a similar content of reducing sugars (20%). Topping did not influence the N, P and K contents of the leaves.

Irrigation increased fresh yield from 12·0 t/ha (225 mm water) to 24·0 t/ha (450 mm water) and dry matter yield from 2·0 to 3·8 t/ha, respectively, in Expt 1.

As Cypriot tobacco growers are paid for fresh yield delivered to the curing plant, the marginal increase of fresh yield with topping will hardly cover the cost of the extra operations involved.
Fertilizer–use efficiency of amended urea materials in flooded rice
Authors: Chauhan H. S. , Mishra B.
Published: March 2009

summary

In a field experiment on a typic hapludoll in 1983 and 1984, deep placement of urea supergranules at 40 and 80 kg N/ha proved to be the best N source, of five tested, for grain production, but at 120 kg N/ha it was similar to neem-cake-coated urea. The results showed that deep placement of urea supergranules can save fertilizer use by 60% compared with prilled urea to obtain the same yield. Shellac-coated urea and dicyandiamide-coated urea was more effective than prilled urea in 1984. Differences in dry-matter production and grain yield were directly related to N uptake by the plants. On average, apparent recovery of applied N increased from 35% for prilled urea to 55, 52·5,46·5 and 37·5% for urea supergranules, neem-cake-coated urea, shellac-coated urea and dicyandiamide-coated urea, respectively.
The relation between the silica content of the diet and the excretion of silica by sheep
Authors: Jones L. H. P. , Handreck K. A.
Published: March 2009

Three diets, with silica contents ranging from 0·10–2·84% SiO2 in the dry matter, were fed to sheep and the distribution of silica between the faeces and urine was measured, together with the concentrations of silica in the rumen liquor and the blood. The sum of the amounts of silica excreted in the urine and faeces was within 1% of the amounts ingested. The amounts excreted in the urine increased with increasing silica content of the diet but reached no more than 205 mg. SiO2/day, apparently being limited by the solubility of silica in the rumen. Since the concentration of silica in the blood remained practically constant it is concluded that the silica which enters the blood stream from the alimentary tract passes rapidly into the urine. The amounts of silica excreted in the urine represented small proportions only of the amounts ingested and since the recoveries of silica in the faeces were so nearly complete it is suggested that silica be re-examined as an indicator for digestibility studies.
Effects of seed advancement and sowing date on establishment, bolting and yield of sugarbeet
Authors: Durrant M. J. , Mash S. J. , Jaggard K. W.
Published: March 2009

An advancing and devernalizing treatment for sugarbeet seed has been developed which, in England, allows sowing to be brought forward safely byc.10 days to around 10 March. Experiments done each year from 1988 to 1991 were used to assess the value of this change. They showed that sugar yield increased by 0·048 t/ha/day because seed advancement resulted in more rapid emergence, and by 0·042 t/ha/day as a result of earlier sowing. As an average of all appropriate data from experiments in England since the 1950s, the advantage of sowing in March is 0·035 t/ha/day. However, the actual change in sowing date which the farmer might achieve will depend on soil type and rainfall. Daily rainfall and evaporation data for eastern England in March and April were used to predict the number and distribution of available machinery work days. On this basis, the average sowing date was predicted to advance by 9 days. Thus the sugar yield improvement which could be produced by advancing and devernalizing beet seed is equivalent to 9 days at 0·035 t/ha/day, plus 0·19 t/ha, orc.0·5 t/ha. In practice, this should translate into an increase of 0·35 t/ha, orc.5% of the average yield.
Influence of plane of nutrition on portal blood flow and the metabolic clearance rate of progesterone in ovariectomized gilts
Authors: Prime G. R. , Symonds H. W.
Published: March 2009

The effects of plane of nutrition on blood flow in the portal vein (PBF) and on the rate of clearance of progesterone from the circulation (MCR) were measured for 14 or 24 h in six ovariectomized gilts given 1 or 3 kg of food per day. On a body weight basis, PBF was significantly increased by the increase in food intake from a mean for all gilts of 14·9 ml/kg.min (1·34 litres/min) on 1 kg to 21·6 ml·kg. min (1·96 litres/min) on 3 kg, a mean increase of 45 %. Metabolic clearance of progesterone was increased by a similar percentage, 47·1%, from 41·0 ml/kg.min (3·70 litres/min) to 60·3 ml/kg.min (5·67 litres/min) by the increase in food intake. Both MCR and PBF were lowest between 04.00 and 06.00 h, increasing after each feed except that when 3 kg/day was fed the MCR remained high throughout the period between meals. In two gilts, blood flow in both the portal vein and hepatic artery (HAF) was measured. The mean PBF and HAF for each pig were 40·6 and 5·8, and 32·4 and 35 ml/kg, min respectively. HAF was 11·2% of total hepatic blood flow.
Modified joint regression analysis for incomplete variety × environment data
Authors: Digby P. G. N.
Published: March 2009

This paper presents an iterative analysis of incomplete variety × environment tables. The analysis estimates potential differences in the sensitivity of varieties to environment effect. It is noted that the technique allows unequal weighting of data, and the special case of a complete table is discussed.
Integrated management of Sesbania, Azolla and urea nitrogen in lowland rice under a rice–wheat cropping system
Authors: Mahapatra B. S. , Sharma G. L.
Published: March 2009

A two-year field experiment on a mollisol at Pantnagar showed that organic sources of N gave generally higher rice yields than the equivalent split dressing of prilled urea (PU). In 1985/86, Sesbania green manuring (40 kg N/ha) and PU (40 kg N/ha) and, in 1986/87, Sesbania (40 kg N/ha) + Azolla (40 kg N/ha) gave significantly higher yields than a split application of 80 kg N/ha as PU. Yield increases were attributed to significant variations in panicles/m2, filled spikelets/panicle and nitrogen uptake by the crop. These components, and grain yield, were significantly correlated with wet soil NH+4-N, which was increased by organic manuring. Wheat grown after each rice crop showed significant residual effects of the different sources of N applied to rice.
Effects of sowing date on the growth and yield of winter oil-seed rape (Brassica napus)
Authors: Jenkins P. D. , Leitch D M. H.
Published: March 2009

Results are reported from experiments carried out in three seasons in an environment with mild winters and early springs in which the date of sowing of winter oil-seed rape was varied from early September to early December. Consistently high seed yields were achieved in the late sowings and, in two of the three seasons, delaying sowing beyond early September resulted in significant yield increases. The pattern of dry-matter accumulation and changes in leaf area index were affected to a large extent by sowing date, but no significant effect on total dry-matter production at final harvest was found. Numbers of axillary inflorescences per plant and, in two of the experiments, numbers of fertile pods/m2, were reduced by late sowing, but large increases in numbers of seed per pod were found in each experiment. Mean weight per seed was reduced when sowing was delayed but there was no consistent effect on oil content. Differences were found between cultivars in the extent to which delayed sowing produced increased yields. It is suggested that early spring growth, delayed flowering and reduced reflexion of radiation during flowering were important factors leading to the high yields achieved by late sowings. No interactions were found between sowing date and plant population density for any yield component in one experiment.
Changes in growth and yield components ofBrassica napusin response toAzotobacterinoculation at different rates of nitrogen application
Authors: Singh Prabhjeet , Bhargava S. C.
Published: March 2009

Inoculation ofBrassica napuscv. ISN–129 withAzotobacter chroococcumfollowing the application of different amounts of nitrogen produced the greatest increase in seed yield and total dry matter when no external nitrogen had been applied. The yield increase in response to inoculation could be attributed to a greater number of primary branches and pods, associated with a higher leaf area index, particularly at the pod-filling stage, and a faster crop growth rate.
Marangoni convection in droplets on superhydrophobic surfaces
Authors: TAM DANIEL , von ARNIM VOLKMAR , McKINLEY G. H. , HOSOI A. E.
Published: March 2009

We consider a small droplet of water sitting on top of a heated superhydrophobic surface. A toroidal convection pattern develops in which fluid is observed to rise along the surface of the spherical droplet and to accelerate downwards in the interior towards the liquid/solid contact point. The internal dynamics arise due to the presence of a vertical temperature gradient; this leads to a gradient in surface tension which in turn drives fluid away from the contact point along the interface. We develop a solution to this thermocapillary-driven Marangoni flow analytically in terms of streamfunctions. Quantitative comparisons between analytical and experimental results, as well as effective heat transfer coefficients, are presented.
Particle clustering in periodically forced straining flows
Authors: MARSHALL J. S.
Published: March 2009

Numerous biomedical and industrial applications require separation or sorting of particles in systems in which it is undesirable to allow particle adhesion to a surface, such as a centrifuge wall and a filter fibre. Such systems typically involve either adhesive particles which could easily foul such surfaces or very delicate particles as is the case with suspensions of biological cells. The current study explores an approach for particle separation based on exposure to an oscillating straining flow, which would be typical for peristaltic and other types of contractive wall motions in a channel or tube. We find that particles immersed in an oscillating straining flow are attracted to the nodal points of the straining field, a phenomenon which we refer to as ‘oscillatory clustering’. A simplified theory of this process is developed for cases with isolated particles immersed in an unbounded uniform straining flow, in which the particle motion is found to be governed by a damped Mathieu equation. Moreover, the drift velocity imposed on particles through oscillatory clustering is sufficient to suspend them against a downward gravitational force in a limit-cycle oscillatory path. Theoretical approximations for the average suspension height and oscillation amplitude are obtained. A discrete-element method (DEM) for colliding and adhesive particles is then employed to examine oscillatory clustering for more realistic systems in which particles collide with each other and with container walls. The DEM is used to examine oscillatory clustering of a particle suspension in an oscillating box and for standing peristaltic waves in a channel, both with and without particle adhesion forces and gravitational forces.
Media, the Olympics and the Search for the “Real China”
Authors: Latham Kevin
Published: March 2009

The Beijing Olympics were about more than just sporting competition. They were about China and its role on the international stage. The Games were explicitly recognized for their role showcasing China's economic, technological, cultural, social and environmental achievements to the rest of the world. The Beijing Games were therefore inevitably going to lead to a process of contestation between competing representations, understandings and identifications of China, and a common motif of this process became the designation of what is or is not the “real China.” This article focuses on the notion of the “real China” and the debates and contestations surrounding it in Chinese and foreign media over the months running up to and during the Olympics. It will identify what these debates and contending claims about the “real China” may reveal for a broader understanding of the role of media in the country and our need to rethink our approaches to both.
The split of a working-class city: urban space, immigration and anarchism in inter-war Barcelona, 1914–1936
Authors: OYÓN JOSÉ LUIS
Published: March 2009

Barcelona was the capital city of European anarchism during the inter-war years. The aim of this article is to discover the sociological and territorial features of the radicalized CNT (the Confederación Nacional del Trabajo), the anarchist union, which generated the summer 1936 revolution. By looking at the role of urban space as a variable in the collective processes of the working class the article argues that the unskilled recent immigrant worker and the neighbourhoods where this working-class figure was dominant were the key protagonists of revolutionary radicalism.
Survival of organic compounds in ejecta from hypervelocity impacts on ice
Authors: Bowden S.A. , Parnell J. , Burchell M.J.
Published: April 2009

Hypervelocity impacts (HVIs) where organic-bearing ice constitutes the target material are important in several aspects of planetary and space science: (1) sampling of planetary surfaces using a hypervelocity projectile to impact the surface and eject surface materials for measurement or collection by a spacecraft; (2) the transfer of organic material between planetary bodies; and (3) providing energy for chemical processes involving surface materials. While small organic molecules (~6 carbon atoms), if present in surface materials, will likely be present in HVI-ejecta, uncertainty remains for larger organic molecules. It is the larger molecular weight compounds which could constitute direct evidence of life, and thus their survival within an HVI-ejecta plume is of key importance when evaluating strategies for life detection on icy bodies. It is not currently known what large organic molecules, and in what concentrations, may be present on icy bodies in the Solar System, but it is highly likely some will be more chemically stable during a HVI than others. Accordingly, in this study we examined a range of chemicals (β,β carotene, stearic acid and anthracene) with molecular weights between 178 and 536 daltons, and three different types of chemical structure. The compounds were solvated in a dimethylsulfoxide/water mixture and frozen. The frozen targets were impacted with steel spheres 1 and 1.5 mm in diameter at velocities of about 4.9 km s−1. Ice ejected during the impact was collected and underwent chemical analysis. The most labile compound (β,β carotene) was only detected (in small amounts) in the ejecta (and only that emitted at the lowest angles of ejection), although the other compounds were present in larger quantities and at a range of ejection angles. A concentration gradient was observed within the ejecta as a function of angle of ejection. This was not the same for both stearic acid and anthracene: the greatest concentrations of stearic acid were found at shallow angles of ejection whereas anthracene was most abundant at both intermediate and large angles of ejection, implying an inverted concentration gradient. These observations may indicate that organic compounds are variably altered and destroyed during a HVI with ice and that the ejecta plume does not sample the original materials equally at all angles of ejection. Future work is planned and will evaluate fractional survival for a greater range of compound types, impact materials and velocities.
Wohlbefinden von Kindern und Jugendlichen
Authors: Bullinger Monika
Published: April 2009

Zusammenfassung. Die Übersichtsarbeit gibt einen Einblick in den aktuellen Stand der Forschung zum Wohlbefinden von Kindern und Jugendlichen. Internationale Studien zum Ländervergleich aber auch nationale und internationale Forschungsarbeiten zur Bedeutung individueller relevanter Faktoren im familiären und weiteren sozialen Kontext von Kindern und Jugendlichen werden vorgestellt. Der Beitrag zeigt außerdem die unterschiedlichen Forschungsperspektiven sowie die Rezeption des Konstruktes Wohlbefinden in den verschiedenen Fachdisziplinen Psychologie und Medizin auf. Nach einer Berücksichtigung von Definitionsversuchen zum Wohlbefinden erfolgt eine Abgrenzung von verwandten Konzepten und Begrifflichkeiten. Die gängigen Ansätze zur Operationalisierung und Messung des Wohlbefindens werden erläutert und entsprechende Verfahren vorgestellt. Ausgehend von diesem Überblick werden weiterführende Forschungsbedarfe bezüglich konzeptuell-theoretischer Aspekte des Wohlbefindens und seiner Förderung spezifiziert. Weitererführender Forschungsbedarf betrifft insbesondere auch die kognitiven, emotionalen sowie sozialen Regulationen des Wohlbefindens im Entwicklungsverlauf, die Verbesserung von Erfassungsmethoden sowie eine verstärkte Beforschung des Wohlbefindens von chronisch kranken Kindern und Jugendlichen.
Wohlbefinden und gesundheitsbezogene Lebensqualität aus einer bevölkerungsbezogenen Perspektive
Authors: Ravens-Sieberer Ulrike , Wille Nora , Nickel Jennifer , Ottova Veronika , Erhart Michael
Published: April 2009

Zusammenfassung. Bevölkerungsbezogene Untersuchungen des Wohlbefindens von Kindern und Jugendlichen ermöglichen die Identifikation von Risikofaktoren und Risikogruppen für ein beeinträchtigtes Wohlbefinden und gesundheitliche Belastungen. In dieser Arbeit wird am Beispiel dreier internationaler bzw. nationaler bevölkerungsbezogener Studien aufgezeigt, wie sich die komplexen Beziehungen zwischen Wohlbefinden und für das Wohlbefinden relevanten Aspekten unter Verwendung komplexer statistischer Modellierungsansätze untersuchen lassen. Die im Modul „Seelisches Wohlbefinden und Verhalten” des Kinder- und Jugendgesundheitssurveys (BELLA-Studie; n = 1700), der Health Behaviour in School-aged Children (HBSC; n = 7000) und der KIDSCREEN Studie (n = 8000) an 11 bis 18jährigen Kindern und Jugendlichen erhobenen Daten zu ihrem Wohlbefinden, psychischen Problemen, personalen familiären und sozialen Ressourcen, schulischer Umgebung sowie Tabak- und Alkoholkonsum werden dazu ausgewertet. Über die Daten jeder der drei Studien wurde je eine lineare Strukturgleichungsmodellanalyse mit Lisrel durchgeführt. Die drei unterschiedlichen nach theoretischen Vorüberlegungen spezifizierten Lisrel Modelle weisen eine akzeptable Datenanpassung auf. Personale, familiäre und soziale Ressourcen, psychische Probleme und schulische Anpassung erweisen sich als bedeutende Prädiktoren des Wohlbefindens. Es finden sich Hinweise auf eine komplexe und reziproke Natur der Beziehung zwischen Wohlbefinden und Tabak- bzw. Alkoholkonsum. Die Überprüfung der spezifizierten komplexen Einflussfaktorenmodelle mit LISREL bestätigt die Ergebnisse bisheriger Untersuchungen detaillierter Aspekte der Korrelate des Wohlbefindens. Die Ergebnisse sind mit theoretischen Arbeiten zum Wohlbefinden vereinbar.
Intercomparison of aerosol extinction measured by Stratospheric Aerosol and Gas Experiment (SAGE) II and III
Authors: Yue Glenn K. , Fromm Michael D. , Shettle Eric P.
Published: April 2009

Stratospheric Aerosol and Gas Experiment (SAGE) II and SAGE III are two satellite experiments designed to monitor aerosol extinction and the concentration of trace gases in the atmosphere using the solar and/or lunar occultation technique. While SAGE III used nine aerosol channels, four of them were centered at wavelengths very close or equal to the four aerosol channels used by SAGE II. Since both satellites conducted measurements between 2002 and 2005, there are comparison opportunities when their measurement locations on the same day are nearly coincident. In this study, the coincidence events are identified, and the aerosol extinction coefficients, color ratios (ratio of the extinction at two wavelengths), and optical depths measured by both satellites are compared. It is found that in the main stratospheric aerosol layer, between about 18 and 26 km, the differences of extinction coefficients are generally within their measurement uncertainties and are less than about 30%. The discrepancy between the wavelength dependence of the aerosol extinction coefficient, color ratio, and optical depth measured by SAGE II and SAGE III is also discussed. In the main stratospheric aerosol layer, the SAGE III mode radius deduced from the color ratio is about 20 to 30% less than the SAGE II mode radius. Wavelength dependence biases of the aerosol extinction coefficient evident in prior releases of SAGE III data persist in version 4.00.
Volatile organic compounds measured in summer in Beijing and their role in ground‐level ozone formation
Authors: Shao Min , Lu Sihua , Liu Ying , Xie Xin , Chang Chichung , Huang Shan , Chen Zhongmin
Published: April 2009

Beijing has long suffered from serious ground‐level ozone pollution, and volatile organic compounds (VOCs) play a key role in ozone formation. To understand the chemical speciation of VOCs in Beijing, nonmethane hydrocarbons (NMHCs) and oxygenated VOCs (OVOCs) were measured in summer in Beijing and nearby provinces (VOCs in this work means NMHCs+OVOCs). A variation of VOC mixing ratios and chemical speciation from 2004 to 2006 was observed at an urban site in Beijing. The typical VOC species, e.g., propane, propene, and toluene, had comparable or lower mixing ratios than levels found in other cities that previously hosted the Olympic Games, while the mixing ratios for isoprene were higher. The chemical compositions of VOCs within Beijing were heavily influenced by vehicular emissions and differed from those obtained in Tianjin and Hebei Province. OVOCs were an important component, accounting for 54% and 37% in the VOC mixing ratio in 2005 and 2006, respectively, and about 40% of the OH loss rates. The main reactive VOC compounds were aldehydes and alkenes. By using isoprene chemistry and the ratio of ethylbenzene to mp‐xylene, the initial mixing ratios of VOCs were estimated. The VOCs had similar variation patterns to ambient ozone and peroxyacetyl nitrate (PAN) concentrations. The correlation between daily maximum ozone concentrations and initial VOCs revealed that ozone formation was sensitive to VOCs for both urban (Peking University, PKU) and rural (Yufa) sites. A reduction in NOx would lead to a decrease in ozone at Yufa, but would cause increased ozone at the PKU site.
Retrieval of stratospheric temperatures from Atmospheric Infrared Sounder radiance measurements for gravity wave studies
Authors: Hoffmann L. , Alexander M. J.
Published: April 2009

The Atmospheric Infrared Sounder (AIRS) on board the National Aeronautics and Space Administration's (NASA's) Aqua satellite has been continuously measuring mid‐infrared nadir and sub‐limb radiance spectra since summer of 2002. These measurements are utilized to retrieve three‐dimensional stratospheric temperature distributions by applying a new fast forward model for AIRS and an accompanying optimal estimation retrieval processor. The retrieval scheme presented in this article does not require simultaneous observations of microwave instruments like the AIRS operational analyses. Instead, independent retrievals are carried out at the full horizontal sampling capacity of the instrument. Horizontal resolution is enhanced by a factor 3 in along‐ and across‐track directions compared with the AIRS operational data. The total retrieval error of the individual temperature measurements is 1.6 to 3.0 K in the altitude range from 20 to 60 km. Retrieval noise is 1.4 to 2.1 K in the same vertical range. Contribution of a priori information to the retrieval results is less than 1% to 2% and the vertical resolution of the observations is about 7 to 15 km. The temperature measurements are successfully compared with ECMWF operational analyses and AIRS operational Level 2 data. The new temperature data set is well suited for studies of stratospheric gravity waves. We present AIRS observations of small‐scale gravity waves induced by deep convection near Darwin, Australia, in January 2003. A strong mountain wave event over the Andes in June 2005 is analyzed in detail. Temperature perturbations derived from the new data set are compared with results from the AIRS operational Level 2 data and coincident measurements of the High Resolution Dynamics Limb Sounder (HIRDLS). The new retrieval does not show response to wave perturbations if the vertical wavelength is below 10 km. For 15 km vertical wavelength, the amplitudes are damped by a factor of two. For vertical wavelengths of greater than 20 km, AIRS shows very similar wave structure to HIRDLS and also has the advantage of providing horizontal phase front information. Data from the new full‐resolution retrieval are far more suitable for gravity wave studies than results from the AIRS operational analysis.
Tectonic interpretation of transient stage erosion rates at different spatial scales in an uplifting block
Authors: Carretier S. , Poisson B. , Vassallo R. , Pepin E. , Farias M.
Published: March 2009

We explore the extent to which it is possible to convert erosion rate data into uplift rate or erosion laws, using a landscape evolution model. Transient stages of topography and erosion rates of a block uplifting at a constant rate are investigated at different spatial scales, for a constant climate, and for various erosion laws and initial topographies. We identify three main model types for the evolution of the mountain‐scale mean erosion rate: “linear”‐type, “sigmoid”‐type and “exponential”‐type. Linear‐type models are obtained for topographies without drainage system reorganization, in which river incision rates never exceed the uplift rate and stepped river terraces converge upstream. In sigmoid‐type and exponential‐type models (typically detachment‐limited or transport‐limited models with a significant transport threshold), drainage growth lasts a long time, and correspond to more than linear transport laws in water discharge and slope. In exponential‐type models, the mean erosion rate passes through a maximum that is higher than the rock uplift rate. This happens when the time taken to connect the drainage network exceeds half the total response time to reach dynamic equilibrium. River incision rates can be much greater than the uplift rate in both cases. In the exponential‐type model, river terraces converge downstream. Observations of a mountain in the Gobi‐Altay range in Mongolia support the exponential‐type model. This suggests that the erosion of this mountain is either detachment‐limited or transport‐limited with a significant transport threshold. This study shows that drainage growth could explain differences in erosion rate measurements on different spatial scales in a catchment.
Spin wave quantization in continuous film with stripe domains
Authors: Ha Seung-Seok , Yoon Jungbum , Lee Sukmock , You Chun-Yeol , Jung Myung-Hwa , Kim Young Keun
Published: April 2009

We investigated the spin wave dynamics of CoFeSiB film, which has a stripe domain structure at a low magnetic field region (<1 kOe). We measured the spin wave excitation spectra by employing Brillouin light scattering. Abnormal field dependence and dispersion relations were observed, and they are similar to spin wave quantization in laterally confined magnetic structures such as arrays of magnetic nanowires. The observed spin wave excitation spectra must be interpreted with spin wave quantization such as Damon–Eshbach mode separation. It was found that the spin wave quantization is related to the stripe magnetic domain structure in continuous film. The physical origin of the quantization is the partial reflection of the propagating spin wave at the periodic stripe domain boundaries.
A theoretical study on the interaction of aromatic amino acids with graphene and single walled carbon nanotube
Authors: Rajesh Chinagandham , Majumder Chiranjib , Mizuseki Hiroshi , Kawazoe Yoshiyuki
Published: March 2009

In this study we have investigated the interaction of phenylalanine (Phe), histidine (His), tyrosine (Tyr), and tryptophan (Tryp) molecules with graphene and single walled carbon nanotubes (CNTs) with an aim to understand the effect of curvature on the non-covalent interaction. The calculations are performed using density functional theory and the Møller–Plesset second-order perturbation theory (MP2) within linear combination of atomic orbitals-molecular orbital (LCAO-MO) approach. Using these methods, the equilibrium configurations of these complexes were found to be very similar, i.e., the aromatic rings of the amino acids prefer to orient in parallel with respect to the plane of the substrates, which bears the signature of weak π-π interactions. The binding strength follows the trend: His<Phe<Tyr<Tryp. Although the qualitative trend in binding energy is almost similar between the planar graphene and rolled nanotube structure but they differ in terms of the absolute magnitude. For the nanotube, the binding strength of these molecules is found to be weaker than the graphene sheet. To get an insight about the nature of these interactions, we have calculated the polarizability of the aromatic motifs of the amino acids. Remarkably, we find excellent correlation between the polarizability and the strength of the interaction; the higher the polarizability, greater is the binding strength. Moreover, we have analyzed the electronic densities of state spectrum before and after adsorption of the amino acid moieties. The results reveal that the Fermi level of the free CNT is red-shifted by the adsorption of the amino acids and the degree of shift is consistent with the trend in polarizability of these molecules.
Surface magnetic structure of epitaxial magnetite thin films grown on MgO(001)
Authors: Kaji Eisaku , Subagyo Agus , Arita Masashi , Sueoka Kazuhisa
Published: April 2009

The crystallographic structure of antiphase domain boundaries (APBs) and the magnetic structure of large domains of magnetite (Fe3O4) thin films, which were epitaxially grown on MgO(001) substrates and annealed in an ambient condition, were investigated by scanning tunneling microscopy (STM), transmission electron microscopy (TEM), magnetic force microscopy (MFM), and scanning electron microscopy with polarization analysis (SEMPA). STM and TEM showed the morphology of the APBs in film surfaces and the bulk, whereas MFM and SEMPA showed the magnetic structure of the surfaces. As in previous paper reported by another group, STM and TEM observations revealed the antiphase domains on a scale from tens of nanometers to a few hundred nanometers. Also MFM measurement showed the magnetic domains on a scale of a few hundred nanometers and large-scale undulations of a few micrometers. Our SEMPA observations of the films displayed large-scale magnetic structures on a scale of a few hundred nanometers to a few micrometers. These large-scale magnetic structures are expected to be induced by the enlargement of magnetic domains that contain magnetic moments aligned along a magnetic easy axis. These moments have in-plane components that make the SEMPA images visible. An air-annealing process is needed to change magnetic couplings in APBs and to form large-scale magnetic ordering.
Truncation model in the triple-degenerate derivative nonlinear Schrödinger equation
Authors: Sánchez-Arriaga G. , Hada T. , Nariyuki Y.
Published: April 2009

The triple-degenerate derivative nonlinear Schrödinger (TDNLS) system modified with resistive wave damping and growth is truncated to study the coherent coupling of four waves, three Alfven and one acoustic, near resonance. In the conservative case, the truncation equations derive from a time independent Hamiltonian function with two degrees of freedom. Using a Poincare map analysis, two parameters regimes are explored. In the first regime we check how the modulational instability of the TDNLS system affects to the dynamics of the truncation model, while in the second one the exact triple degenerated case is discussed. In the dissipative case, the truncation model gives rise to a six dimensional flow with five free parameters. Computing some bifurcation diagrams the dependence with the sound to Alfven velocity ratio as well as the Alfven modes involved in the truncation is analyzed. The system exhibits a wealth of dynamics including chaotic attractor, several kinds of bifurcations, and crises. The truncation model was compared to numerical integrations of the TDNLS system.
Influences of degree inhomogeneity on average path length and random walks in disassortative scale-free networks
Authors: Zhang Zhongzhi , Zhang Yichao , Zhou Shuigeng , Yin Ming , Guan Jihong
Published: March 2009

Various real-life networks exhibit degree correlations and heterogeneous structure, with the latter being characterized by power-law degree distribution P(k)∼k−γ, where the degree exponent γ describes the extent of heterogeneity. In this paper, we study analytically the average path length (APL) of and random walks (RWs) on a family of deterministic networks, recursive scale-free trees (RSFTs), with negative degree correlations and various γ∊(2,1+ln 3/ln 2], with an aim to explore the impacts of structure heterogeneity on the APL and RWs. We show that the degree exponent γ has no effect on the APL d of RSFTs: In the full range of γ, d behaves as a logarithmic scaling with the number of network nodes N (i.e., d∼ln N), which is in sharp contrast to the well-known double logarithmic scaling (d∼ln ln N) previously obtained for uncorrelated scale-free networks with 2≤γ<3. In addition, we present that some scaling efficiency exponents of random walks are reliant on the degree exponent γ.
Unusual products observed in gas-phase WxOy−+H2O and D2O reactions
Authors: Rothgeb David W. , Hossain Ekram , Kuo Angela T. , Troyer Jennifer L. , Jarrold Caroline Chick , Mayhall Nicholas J. , Raghavachari Krishnan
Published: March 2009

Addition of H2O and D2O to small tungsten suboxide cluster anions WxOy− (x=1–4; y≤3x) was studied using mass spectrometric measurements from a high-pressure fast flow reactor. Within the WOy− mass manifold, which also includes WO4H−, product masses correspond to the addition of one to three H2O or D2O molecules. Within the W2Oy− cluster series, product distributions suggest that sequential oxidation W2Oy−+H2O/D2O→W2Oy+1−+H2/D2 occurs for y<5, while for W2O5−, W2O6H2−/W2O6D2− is primarily produced. W2O6− does not appear reactive. For the W3Oy− cluster series, sequential oxidation with H2 and D2 production occurs for y<6, while W3O6− and W3O7− produce W3O7H2−/W3O7D2− and W3O8H2−/W3O8D2−, respectively. Lower mass resolution in the W4Oy− mass range prevents definitive product assignments, but intensity patterns suggest that sequential oxidation with H2/D2 evolution occurs for y<6, while W4Oy+1H2−/W4Oy+1D2− products result from addition to W4O6− and W4O7−. Based on bond energy arguments, the H2/D2 loss reaction is energetically favored if the new O–WxOy− bond energy is greater than 5.1 eV. The relative magnitude of the rate constants for sequential oxidation and H2O/D2O addition for the x=2 series was determined. There are no discernable differences in rate constants for reactions with H2O or D2O, suggesting that the H2 and D2 loss from the lower-oxide/hydroxide intermediates is very fast relative to the addition of H2O or D2O.
Structure-thermodynamics relation of electrolyte solutions
Authors: Kalcher Immanuel , Dzubiella Joachim
Published: April 2009

The structure of aqueous LiCl, NaCl, KCl, CsCl, KF, and NaI solutions is calculated by molecular dynamics (MD) simulations of the frequently employed Dang force-field in SPC/E water. By using liquid state theory, we integrate the structure to obtain the electrolytes’ osmotic coefficient ϕ and systematically investigate force-field quality and structural consequences to ion-specific bulk thermodynamics. The osmotic coefficients ϕχ calculated from the exact compressibility route for the cation-Cl− force-fields match experiments for concentrations ρ≲2M, while NaI and KF parameters fail. Comparison of ϕχ with ϕv from the virial route, which relies on the pair potential approximation, shows that many-body effects become important for all salts above ρ≃0.5M. They can be efficiently corrected, however, by employing a salt-type and ρ-dependent dielectric constant ϵ(ρ), generalizing previous observations on NaCl only. For physiological concentrations, ρ≲0.5M, the specific osmotic behavior is found to be determined by the short-ranged cation-anion pair potential only and is strongly related to the second virial coefficient of the latter. Presented methods and findings, based on simple integrations over the electrolyte structure, enable efficient MD force-field refinement by direct benchmarking to the sensitive electrolyte thermodynamics, instead to noncollective, single ion properties.
Low frequency structural dynamics of warm dense matter
Authors: Gregori G. , Gericke D. O.
Published: April 2009

Measurements of the microscopic response of warm dense matter have been demonstrated by multi-keV inelastic x-ray scattering using laser-based sources. These techniques have been used to study the high frequency electron correlations (plasmons) in low to mid-Z plasmas. The advent of fourth generation light sources will provide high fluxes of narrowband and coherent x rays that will allow to look at the low frequency correlations (the ion-acoustic waves). In this paper we present an analysis of such low frequency modes by calculating the frequency dependent ion-ion structure factor. Our model includes all the relevant multibody contributions arising from strong coupling and nonideal plasma effects. In particular, the ion-ion structure factor is obtained within the memory function formalism by satisfying a finite number of sum rules. This work could be used as a basis to a direct experimental test of dense plasma model as soon as keV free electron laser sources will become available.
An instrument for combining x-ray multiple diffraction and x-ray topographic imaging for examining crystal microcrystallography and perfection
Authors: Lai X. , Ma C. Y. , Roberts K. J. , Cardoso L. P. , dos Santos A. O. , Bogg D. , Miller M. C.
Published: March 2009

Diffraction imaging using x-ray topography (XRT) and x-ray multiple diffraction (XRMD) provide valuable tools for examining the growth defects in crystals and the distributions from ideal lattice symmetry (microcrystallography). The topographic x-ray multiple diffraction microprobe (TMDM) combines the complementary aspects of both techniques enabling XRT and XRMD studies within the same instrument providing a useful resource for the structural characterization of materials that are not very stable in vacuum and electron beam environments. The design of the TMDM instrument is described together with data taken on GaAs (001) and potassium dihydrogen phosphate (001).
An effective Hamiltonian survey of the anharmonic vibrational state space of SCCl2 up to the dissociation energy
Authors: Chowdary Praveen D. , Gruebele Martin
Published: April 2009

We survey about 3.5 million feature states in the anharmonic state space of SCCl2 to answer three questions: how sharp is the threshold for intramolecular vibrational energy redistribution (IVR), how do specific resonances and regions of state space contribute to the threshold, and how many undiluted spectral features (or localized eigenstates) persist as energy increases? As quantitative measures we use the dilution factor σ, Heller’s F, and e, which describes how close to the edge of state space a feature lies. We find that an IVR threshold can be identified and lies between 250 and 300 THz. The threshold is softened because different resonances act at different energies in different parts of state space. According to our calculation, about 1 in 103 feature states remains undiluted near the dissociation limit of SCCl2. This fraction matches the number of sharp spectral features observed recently by experiment when symmetry and Franck–Condon factors are taken into account, and it is in agreement with an analytical model that predicts an increasing fraction of undiluted features as molecular size increases.
Polarized micro-Raman spectroscopy study of pentacene thin films
Authors: Stenger Ingrid , Frigout Alexandre , Tondelier Denis , Geffroy Bernard , Ossikovski Razvigor , Bonnassieux Yvan
Published: March 2009

We report on polarized micro-Raman spectroscopy study of two pentacene thin films exhibiting different microstructures: a well-ordered sample and a more disordered one. We have investigated the frequency range of the intramolecular C–H bending modes in the plane of the pentacene molecule and proposed an interpretation of the Raman spectra. The use of symmetry properties of the two intramolecular (uncoupled) modes allowed us to unambiguously identify it among the five main contributions observed in this spectral range. The three other modes were assumed to be resulting from molecular coupling effect owing to their different behavior upon the samples microstructure.
All dielectric hard x-ray mirror by atomic layer deposition
Authors: Szeghalmi Adriana , Senz Stephan , Bretschneider Mario , Gösele Ulrich , Knez Mato
Published: April 2009

Mirrors consisting of Al2O3 and Ta2O5 (∼2 nm film thickness) nanolaminates for hard x-ray wavelengths were produced by atomic layer deposition and characterized. Atomic force microscopy and transmission electron microscopy (TEM) proved extremely smooth surfaces of the mirrors, which are critical for highest reflectance. TEM images showed sharp interfaces between the oxides. The experimental x-ray reflectivity data were theoretically modeled and indicated minimal random thickness variations in the individual layers. Additionally, a depth graded sample with a total thickness of ∼4 μm for focusing applications in transmission (Laue) geometry and capillaries was coated.