bluuebunny/crossref_metadata_2025 huggingface dataset:
Über Bau und Umbau des größten Werftportalkrans der Welt – Schweißtechnische Abenteuer bei der Weiterverwendung eines technologieintensiven Investitionsguts
Authors: Roos Horst J.
Published: December 2009

Der weltgrößte Kran, ein über 30 Jahre alter Werftportal‐Kran aus Malmö, Schweden, wurde verkauft, im Jahr 2002 dort zerlegt, demontiert und per Schiff in die größte Werft der Welt nach Ulsan in Süd‐Korea gebracht. Der Beitrag berichtet über den Aufbau in der Werft Hyundai Heavy Industries (HHI), wo der Kran neu zusammenschweißt wurde und nun nach dreijähriger Planungszeit und einjähriger Bauzeit für eine neuartige Slip‐Anlage für Schiffe in einem Offshore Yard mit geänderter Aufgabenstellung in Betrieb genommen wurde.

Erection and conversion of the largest Goliath Crane of the world – Welding technique for the re‐use of a technologic producer good.

A 30 year‐old Goliath Crane for ship‐building was sold to Werft Hyundai Heavy Industries (HHI), along with two slewing cranes, by a Swedish company. It was knocked down and dismantled at Malmö, Sweden and transported by ship to Ulsan, South Korea, in order to be re‐erected and re‐used for a newly developed “Ground‐Shipbuilding‐System” in the place of real estate of an offshore yard.
Simplified dynamic analysis of eccentric buildings with a setback. 1: the effect of mass irregularity
Authors: Georgoussis George K.
Published: December 2009

The dynamic response of eccentric buildings with a setback is investigated and a simple method is proposed for assessing vibration frequencies and modal base shears and torques. With the proposed methodology the aforementioned basic dynamic quantities are determined by analysing first the symmetrical counterpart structure and then an equivalent one‐storey eccentric system. The type of buildings examined represents the class of tall structures with a significant reduction in the size of floor plans above a certain level, but without any modification on the structural system, which is considered to be uniform over the height of the building, but eccentric to the mass axis. It is shown that the vertical mass irregularity thus produced increases substantially the contribution of the higher modes of vibration to the total response of such structures and this contribution increases with the height of the tower structure above the setback level. A number of common buildings with a mixed‐bent‐type structural system are analysed by the proposed method and the results are compared with more accurate results obtained by three‐dimensional dynamic analyses. Copyright © 2009 John Wiley & Sons, Ltd.
Sampling strategies for whole genome association studies in aquaculture and outcrossing plant species
Authors: HAYES B. J. , MACLEOD I. M. , BARANSKI M.
Published: December 2009

A number of farmed species are characterized by breeding populations of large full-sib families, including aquaculture species and outcrossing plant species. Whole genome association studies in such species must account for stratification arising from the full-sib family structure to avoid high rates of false discovery. Here, we demonstrate the value of selective genotyping strategies which balance the contribution of families across high and low phenotypes to greatly reduce rates of false discovery with a minimal effect on power.
Session 1: Allergic disease Nutrition as a potential determinant of asthma
Authors: Devereux Graham
Published: December 2009

Asthma is characterised by chronic lung airway inflammation, increased airway responsiveness and variable airflow obstruction. In Westernised countries asthma is a public health concern because of its prevalence, associated ill health and high societal and healthcare costs. In recent decades there has been a marked increase in asthma prevalence, particularly in Westernised countries. It has been proposed that changing diet has contributed to the increase in asthma. Several dietary hypotheses exist; the first relates the increase in asthma to declining dietary antioxidant intake, the second to decreased intake of long-chainn-3 PUFA and increasing intake ofn-6 PUFA. Vitamin D supplementation and deficiency have also been hypothesised to have contributed to the increase in asthma. Observational studies have reported associations between asthma and dietary antioxidants (vitamin E, vitamin C, carotenoids, Se, flavonoids, fruit), lipids (PUFA, butter, margarine, fish) and vitamin D. However, supplementing the diets of adults with asthma with antioxidants and lipids has minimal, if any, clinical benefit. There is growing interest in the possibility that childhood asthma is influenced by maternal diet during pregnancy, with studies highlighting associations between childhood asthma and maternal intake of some nutrients (vitamin E, vitamin D, Se, PUFA) during pregnancy. It has been suggested that maternal diet during pregnancy influences fetal airway and/or immune development. Further intervention studies are needed to establish whether modification of maternal nutrient intake during pregnancy can be used as a healthy low-cost public health measure to reduce the prevalence of childhood asthma.
Session 2: Other diseases Dietary management of osteoporosis throughout the life course
Authors: Earl Susie , Cole Zoe A. , Holroyd Christopher , Cooper Cyrus , Harvey Nicholas C.
Published: December 2009

Osteoporosis-related fractures have a major impact on health at the individual and societal levels, through associated morbidity and increased mortality. Up to 50% of women and 20% of men at age 50 years may have a fragility fracture in their remaining lifetimes. Nutrition is important throughout the life course. Thus, adequate Ca and vitamin D intake has been shown to reduce risk of fracture in old age. Other factors such as protein and vitamin K may also be important, although the evidence here is less strong. In childhood Ca or vitamin D supplementation trials have demonstrated modest short-term increases in bone mass, but the long-term implications have not been established. Over recent years it has become apparent that maternal nutrition may have critical and far-reaching persistent consequences for offspring health. Thus, reduced maternal fat stores and low levels of circulating 25-hydroxyvitamin D in pregnancy are associated with reduced bone mass in the offspring; placental Ca transport may be key to these relationships. Wider maternal dietary patterns have also been shown to predict offspring bone mass. These data suggest that an interventional approach aimed at specific micronutrients, such as vitamin D, should be complemented by general optimisation of the mother's diet and lifestyle in order to maximise intrauterine bone mineral accrual and postnatal skeletal growth and thus reduce the burden of osteoporotic fractures in future generations.
Plenary Lecture 2 Transcription factors, regulatory elements and nutrient–gene communication
Authors: Cousins Robert J. , Aydemir Tolunay B. , Lichten Louis A.
Published: December 2009

Dramatic advances have been made in the understanding of the differing molecular mechanisms used by nutrients to regulate genes that are essential for their biological roles to carry out normal metabolism. Classical studies have focused on nutrients as ligands to activate specific transcription factors. New interest has focused on histone acetylation as a process for either global or limited gene activation and is the first mechanism to be discussed. Nuclear ATP-citrate lyase generates acetyl-CoA, which has been shown to have a role in the activation of specific genes via selective histone acetylation. Transcription factor acetylation may provide a second mode of control of nutrient-responsive gene transcription. The third mechanism relates to the availability of response elements within chromatin, which as well as the location of the elements in the gene may allow or prevent transcription. A fourth mechanism involves intracellular transport of Zn ions, which can orchestrate localized enzyme inhibition–activation. This process in turn influences signalling molecules that regulate gene expression. The examples provided in the present review point to a new level of complexity in understanding nutrient–gene communication.
Low velocity ion slowing down in a strongly magnetized plasma target
Authors: Deutsch C. , Popoff R.
Published: December 2009

Ion projectile stopping at velocity smaller than target electron thermal velocity in a strong magnetic field is investigated within a novel diffusion formulation, based on Green-Kubo integrands evaluated in magnetized one component plasma models, respectively, framed on target ions and electron. Analytic expressions are reported for slowing down orthogonal and parallel to an arbitrary large magnetic field, which are free from the usual uncertainties plaguing the standard perturbative derivations.
Laser second harmonic generation in a rippled density plasma in the presence of azimuthal magnetic field
Authors: Verma U. , Sharma A.K.
Published: December 2009

The strong azimuthal magnetic fields, observed in many laser plasma experiments, are shown to be a potential source of second harmonic generation. The laser imparts oscillatory velocity to electrons and exerts a longitudinal pondromotive force on them. This force in conjunction with the azimuthal magnetic field and density ripple produces a second harmonic current with significant transverse component. The latter produces resonant second harmonic radiation.
Tree growth and age in an ancient Hawaiian wet forest: vegetation dynamics at two spatial scales
Authors: Hart Patrick J.
Published: December 2009

In this study I document the growth rate and age of trees in an old-growth montane Hawaiian wet forest and use these results to evaluate the cyclic succession model for forest dynamics. I used two methods to estimate the age of trees – the crown-class model and radiocarbon dating. Over 6000 trees belonging to eight species were tagged and measured over 7 y on Hawaii Island. Growth rates for the dominant tree (Metrosideros polymorpha) were relatively low (mean = 1.3 mm y−1) and varied with tree size and crown class. 14C-based age estimates for 27 M. polymorpha trees loosely corroborated estimates based on the crown-class method. The oldest tree dated by 14C had a median age of 647 y BP, placing it among the oldest documented angiosperm trees in the northern hemisphere. 14C dating revealed that the upper canopy may be comprised of three distinct age groups of M. polymorpha trees of similar size, with the median age of each group separated by 200–250 y. The high density of large, very old trees in multiple groups is unusual for a tropical forest and indicates that forest development may occur through gap-phase regeneration at a fine scale and stand-level mortality at a coarser scale.
Seedling establishment of epiphytic orchids in forests and coffee plantations in Central Veracruz, Mexico
Authors: Scheffknecht Susanne , Winkler Manuela , Hülber Karl , Rosas Martín Mata , Hietz Peter
Published: December 2009

The distribution of epiphytes differs between branches within tree crowns as well as within habitats. Where the original forests have been lost, shade coffee plantations can be important refuges for epiphytes, but are not suitable for all species. To understand what affects habitat quality, we transplanted 1440 seedlings each of two orchids, one, Lycaste aromatica, restricted to forests, the other, Jacquiniella teretifolia, common on trees in coffee plantations and in forests. Seedling mortality and growth were compared between three forests, three young and three old coffee plantations to test for differences between habitats and to analyse which habitat features affect growth and mortality. In J. teretifolia there was no clear pattern of habitat effect on mortality (c. 0.08 mo−1), but the production of new shoots was higher in coffee plantations than in forests. In L. aromatica, growth rates as well as seedling mortality increased over time. During the last census growth rates in forests (1.8 mm mo−1) were significantly higher than in old (0.9 mm mo−1) and young (1.2 mm mo−1) coffee plantations, and seedling mortality was about four times higher in old (0.10 mo−1) and young (0.11 mo−1) coffee plantations than in forests (0.025 mo−1), which may explain the natural absence of L. aromatica from coffee plantations. Mortality in L. aromatica at individual sites was negatively correlated with bryophyte cover on branches (Pearson r = –0.75) and positively with lichen cover (r = 0.70) and canopy openness (r = 0.75). Branch cover with non-vascular epiphytes, whether directly responsible by improving the water supply to epiphytes or indicative of differences in microclimate, may be a useful indicator of suitable habitats for vascular epiphytes.
Diversity and body size of dung beetles attracted to different dung types along a tropical land-use gradient in Sulawesi, Indonesia
Authors: Shahabuddin  , Hidayat Purnama , Manuwoto Sjafrida , Noerdjito Woro A. , Tscharntke Teja , Schulze Christian H.
Published: December 2009

Dung beetles are a functionally important component of most terrestrial ecosystems, but communities change with habitat disturbance and deforestation. In this study, we tested if dung beetle ensembles on dung of introduced cattle and of the endemic anoa, a small buffalo, are affected differentially by habitat disturbance. Therefore, we exposed 10 pitfall traps, five baited with anoa and five baited with cattle dung, per site in six habitat types ranging from natural and selectively logged rain forest to three types of agroforestry system (characterized by different management intensity) and open areas (n = 4 replicate sites per habitat type) at the margin of Lore Lindu National Park, Central Sulawesi, Indonesia. We found 28 species, 43% of which were endemic to Sulawesi. Species richness, abundance and biomass declined from natural forest towards open area. Large-bodied species appeared to be more sensitive to habitat disturbance and the ratio of large to small-sized dung beetles declined with land-use intensity. Although selectively logged forest and cocoa agroforestry systems had lower species richness compared with natural forest, they appeared to maintain a high portion of species originally inhabiting forest sites. The similarity of dung beetle ensembles recorded at forest and agroforestry sites reflects the high similarity of some habitat variables (e.g. vegetation structure and microclimate) between both habitat types compared with open areas. Species richness and abundances as well as species composition, which was characterized by decreases in mean body size, changed with land-use intensity, indicating that dung type is less important than habitat type for determining ensemble structure of these Indonesian dung beetles.
Host size and abundance of hemiepiphytes in a subtropical stand of Brazilian Atlantic Forest
Authors: Orihuela Rodrigo Leonel Lozano , Waechter Jorge Luiz
Published: December 2009

Hemiepiphytes comprise two major categories, those that begin their life cycle as epiphytes and later establish soil contact through long descendent roots (primary hemiepiphytes), and those that germinate in the soil and climb up using adherent roots, eventually becoming epiphytes after losing soil contact (secondary hemiepiphytes) (Putz & Holbrook 1986). In several features root-climbing lianas are similar to secondary hemiepiphytes, including adhesion by adventitious roots, ability to colonize host-trees of different sizes (Putz 1984), and colonization generally restricted to a single phorophyte, differing mainly in the retention of soil contact through strong stems.
In Quest of Babylonian Tannaitic Traditions: The Case ofTanna D'Bei Shmuel
Authors: Cohen Barak Shlomo
Published: December 2009

The question of the existence of Babylonian rabbinic traditions dating from the mishnaic period (pre-220 CE) has not been thoroughly and methodically addressed in the scholarly literature. Historians have pointed out that several rabbis were active in Babylonia during the mishnaic period; some researchers have even suggested that in this early period, organized rabbinic intellectual activity already existed in cities such as Nisibis, Nehardea, and Husal. However, a systematic examination of halakhot whose provenance was Babylonia in the mishnaic period has yet to be undertaken. Most prior attempts to uncover Babylonian rabbinic activity from this period have focused on a few traditions ascribed to Tannaim who had a known connection to Babylonia, such as R. Judah b. Bathyra, R. Nathan, and R. Hiyya (the “Babylonians,” as they are sometimes called in rabbinic literature). In light of the absence of a systematic study of Babylonian pre-talmudic rabbinic traditions, Gafni came to the following conclusion, one that this paper will support with solid evidence:

Even if there was a composed Babylonian halakhic tradition that originated before the end of the mishnaic period, it seems that the Palestinian tradition was accepted as the main tradition of the Babylonian sages already at the beginning of the amoraic period. Moreover, when this tradition penetrated into the Babylonian centers of learning, it seems to have completely pushed aside other traditions, causing them to become almost untraceable…. This subject still awaits thorough treatment by talmudic researchers, and at this stage we can discuss only the amount of rabbinic intellectual activity that existed in Babylonia before the talmudic period began…. Reason dictates that after the destruction of the Temple and the Bar-Kochba revolt, as sages began to arrive in Babylonia, the basic foundations of the rabbinic activity were established.
How Does Cognitive Bias Modification Affect Anxiety? Mediation Analyses and Experimental Data
Authors: Salemink Elske , van den Hout Marcel , Kindt Merel
Published: December 2009

Background: There is overwhelming evidence that anxiety is associated with the tendency to interpret information negatively. The causal relationship between this interpretive bias and anxiety has been examined by modifying interpretive bias and examining effects on anxiety. A crucial assumption is that the effect of the procedure on anxiety is mediated by change in interpretive bias rather than being a direct effect of the procedure. Surprisingly, this had not previously been tested. Aim: The aim is to test whether altered interpretive bias, following Cognitive Bias Modification of Interpretations (CBM-I), affected anxiety. Method: Mediational path analyses were conducted to test the hypothesis that changes in anxiety are due to changes in interpretive bias. A separate experiment was conducted to test which elements of the procedure could be responsible for a direct mood effect. Results: Results from mediation analyses suggested that changes in trait anxiety, after performing CBM-I, were indeed caused by an altered interpretive bias, whilst changes in state anxiety appear to be caused by the procedure itself. The subsequent experiment showed that state anxiety effects could be due to exposure to valenced materials. Conclusions: Changed state anxiety observed after CBM-I is not a valid indicator of a causal relationship. The finding that CBM-I affected interpretive bias, which in turn affected trait anxiety, supports the assumption of a causal relationship between interpretive bias and trait anxiety. This is promising in light of possible clinical implications.
A Ricardian analysis of Mexican farms
Authors: MENDELSOHN ROBERT , ARELLANO-GONZALEZ JESUS , CHRISTENSEN PETER
Published: December 2009

This paper measures the impact of climate on Mexican agriculture using a Ricardian analysis. The analysis relies on economic data from 621 individual farms that were collected in 2002. Data on climate, elevation, soils, and distance to nearest city were matched with each farm. The analysis reveals that farmland values in Mexico are sensitive to climate. On average, warmer temperatures reduce land value by 4,000 to 6,000 pesos per degree Celsius. Examining three climate scenarios for 2100, the models predict average losses of between −42% to −54% of land value in Mexico. As a percent of income, rainfed farms will suffer slightly larger damages than irrigated farms but comparisons between small and large farms are mixed.
Healthy food availability in small urban food stores: a comparison of four US cities
Authors: Laska Melissa Nelson , Borradaile Kelley E , Tester June , Foster Gary D , Gittelsohn Joel
Published: December 2009

Objective

Given that small food stores may be important retail food sources in low-income urban communities, our objective was to examine cross-city comparative data documenting healthy food availability within such facilities, particularly those located in low-income areas and nearby schools.

Design

Food stores in Baltimore, Maryland; Minneapolis/St. Paul, Minnesota; Oakland, California; and Philadelphia, Pennsylvania were selected for assessment based on proximity to low-income schools. Stores were defined as: (i) single-aisle (n 45); (ii) small (2–5 aisles; n 52); and (iii) large (≥6 aisles; n 8). Staff conducted in-store audits to assess the presence/absence of twenty-eight healthy items, organized within five categories: (i) fresh fruits/vegetables, (ii) processed fruits/vegetables, (iii) healthy beverages/low-fat dairy, (iv) healthy snacks and (v) other healthy staple foods.

Results

The availability of healthy food items was low, particularly in single-aisle and small stores, and there was significant cross-site variability in the availability of healthy snacks (P < 0·0001) and other healthy staple foods (P < 0·0001). No cross-site differences existed for fruits/vegetables or healthy beverages/low-fat dairy availability. Healthy food availability scores increased significantly with store size for nearly all food/beverage categories (P < 0·01).

Conclusions

Overall, healthy food availability in these venues was limited. Region-specific factors may be important to consider in understanding factors influencing healthy food availability in small urban markets. Data suggest that efforts to promote healthy diets in low-income communities may be compromised by a lack of available healthy foods. Interventions targeting small stores need to be developed and tailored for use in urban areas across the USA.
Numerical simulation of the Filchner overflow
Authors: Wilchinsky Alexander V. , Feltham Daniel L.
Published: December 2009

The plume of Ice Shelf Water (ISW) flowing into the Weddell Sea over the Filchner sill contributes to the formation of Antarctic Bottom Water. The Filchner overflow is simulated using a hydrostatic, primitive equation three‐dimensional ocean model with a 0.5–2 Sv ISW influx above the Filchner sill. The best fit to mooring temperature observations is found with influxes of 0.5 and 1 Sv, below a previous estimate of 1.6 ± 0.5 Sv based on sparse mooring velocities. The plume first moves north over the continental shelf, and then turns west, along slope of the continental shelf break where it breaks up into subplumes and domes, some of which then move downslope. Other subplumes run into the eastern submarine ridge and propagate along the ridge downslope in a chaotic manner. The next, western ridge is crossed by the plume through several paths. Despite a number of discrepancies with observational data, the model reproduces many attributes of the flow. In particular, we argue that the temporal variability shown by the observations can largely be attributed to the unstable structure of the flow, where the temperature fluctuations are determined by the motion of the domes past the moorings. Our sensitivity studies show that while thermobaricity plays a role, its effect is small for the flows considered. Smoothing the ridges out demonstrate that their presence strongly affects the plume shape around the ridges. An increase in the bottom drag or viscosity leads to slowing down, and hence thickening and widening of the plume.
Effects of exhumation kinematics and topographic evolution on detrital thermochronometer data
Authors: Whipp D. M. , Ehlers T. A. , Braun J. , Spath C. D.
Published: December 2009

Detrital thermochronometer data collected from modern rivers or sedimentary basins have the potential to record the evolution of topographic relief, fault kinematics and erosion within drainage basins. However, few studies have addressed the effects of these different factors on detrital thermochronometer age distributions. Here we use transient 3‐D thermokinematic and landform evolution models to simulate the effects of time‐varying topography and fault kinematics on the thermal field through which detrital samples cool. Cooling‐rate‐dependent apatite (U‐Th)/He (AHe), zircon fission track and muscovite 40Ar/39Ar (MAr) grain age distributions are predicted for samples collected from modern river and basin sediments. These distributions are interpreted to determine the sensitivity of different thermochronometer systems to denudation and deformation histories in drainage basins of varying size. We find that detrital thermochronometers in rapidly eroding regions have a strong sensitivity to the kinematics of exhumation, but lack sensitivity to changes in topographic relief under most conditions. In addition, we find potential for significant overestimation of denudation rates derived from conventional 1‐D age‐elevation relationships as compared to 3‐D model‐prescribed rates. At rapid (∼2.5 mm/y) model‐prescribed denudation rates, 1‐D techniques predict rates that are ∼5 and ∼2 times greater than the 3‐D model rate for the AHe and MAr systems, respectively. In models that explore age distributions in foreland basin sediments, we confirm that the lag time concept is a useful and reliable means for identifying denudation rate changes as no significant change in lag time occurs for changing topographic relief scenarios.
Siderite at lower mantle conditions and the effects of the pressure‐induced spin‐pairing transition
Authors: Lavina B. , Dera P. , Downs R. T. , Prakapenka V. , Rivers M. , Sutton S. , Nicol M.
Published: December 2009

Siderite (FeCO3) forms a complete solid solution with magnesite (MgCO3), the most likely candidate for a mantle carbonate. Our experiments with natural siderite reveal spin pairing of d‐orbital electrons of Fe2+ at 43 GPa, as evidenced by a sharp volume collapse of about 10%. The initially colorless crystals assume an intense green color after the transition, which progressively turns to red above 60 GPa. We present clear evidence for the instability of an intermediate spin state in siderite at ambient temperature. At the transition pressure, domains of high and low spin siderite coexist. The unit cell volume difference between magnesite and siderite is significantly decreased by the spin transition, enhancing the solubility between the two calcite‐type minerals. A siderite component in magnesite at lower mantle pressure would significantly increase its density and slightly increase the carbonate bulk modulus.
Capture of solar wind alpha‐particles by the Martian atmosphere
Authors: Chanteur G. M. , Dubinin E. , Modolo R. , Fraenz M.
Published: December 2009

Integration along He++ test‐particle trajectories in the self‐consistent electromagnetic fields generated by three‐dimensional hybrid simulations of the solar wind/Mars interaction is used to evaluate the removal of solar wind α‐particles due to charge‐exchange processes with neutral species of the Martian exosphere. The total removal rate of solar wind He++ ions, transformed into either singly ionised or neutral helium, is equal to 6.7 × 1023 s−1, which corresponds approximately to 30% of the flux of solar α‐particles through the planetary cross‐section. The deposition rate of helium neutral atoms, created by double electronic capture on exospheric oxygen, impacting the exobase, and penetrating below where it can be trapped, is about 1.5 × 1023 s−1. That means an important contribution of the solar wind source to the helium balance of the Martian atmosphere. The implantation of the solar helium into the Martian atmosphere shows an asymmetry related to the orientation of the motional electric field of the solar wind, −VSW × BIMF.
Mesospheric inversion layer and sprites
Authors: Fadnavis S. , Siingh Devendraa , Singh R. P.
Published: December 2009

The vertical structure of temperature observed by Sounding of Atmosphere using Broadband Emission Radiometry (SABER) aboard Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) and sprites observations made during the Eurosprite 2003–2007 observational campaign were analyzed. Sprite observations were made at two locations in France, namely Puy de Dôme (45°46′19.2″N; 02°57′44.64″E; 1.464 km altitude) in the French Massif Central and at the Pic du Midi (42°56′11″N; 00°08′34″E; 2.877 km altitude) in the French Pyrénées. It is observed that the vertical structure of temperature shows evidence for a Mesospheric Inversion Layer (MIL) on those days on which sprites were observed. A few events are also reported in which sprites were not recorded, although there is evidence of a MIL in the vertical structure of the temperature. It is proposed that breaking gravity waves produced by convective thunderstorms facilitate the production of (1) sprites by modulating the neutral air density and (2) MILs via the deposition of energy. The same proposition has been used to explain observations of lightings as well as both MILs and lightning arising out of deep convections.
Estimating the uncertainty of using GPS radio occultation data for climate monitoring: Intercomparison of CHAMP refractivity climate records from 2002 to 2006 from different data centers
Authors: Ho Shu‐peng , Kirchengast Gottfried , Leroy Stephen , Wickert Jens , Mannucci Anthony J. , Steiner Andrea , Hunt Doug , Schreiner William , Sokolovskiy Sergey , Ao Chi , Borsche Michael , von Engeln Axel , Foelsche Ulrich , Heise Stefan , Iijima Byron , Kuo Ying‐Hwa , Kursinski Rob , Pirscher Barbara , Ringer Mark , Rocken Chris , Schmidt Torsten
Published: December 2009

To examine the suitability of GPS radio occultation (RO) observations as a climate benchmark data set, this study aims at quantifying the structural uncertainty in GPS RO‐derived vertical profiles of refractivity and measured refractivity trends obtained from atmospheric excess phase processing and inversion procedures. Five years (2002–2006) of monthly mean climatologies (MMC) of retrieved refractivity from the experiment aboard the German satellite CHAMP generated by four RO operational centers were compared. Results show that the absolute values of fractional refractivity anomalies among the centers are, in general, ≤0.2% from 8 to 25 km altitude. The median absolute deviations among the centers are less than 0.2% globally. Because the differences in fractional refractivity produced by the four centers are, in general, unchanging with time, the uncertainty of the trend for fractional refractivity anomalies among centers is ±0.04% per 5 years globally. The primary cause of the trend uncertainty is due to different quality control methods used by the four centers, which yield different sampling errors for different centers. We used the National Centers for Environmental Prediction reanalysis in the same period to estimate sampling errors. After removing the sampling errors, the uncertainty of the trend for fractional refractivity anomalies among centers is between −0.03 and 0.01% per 5 years. Thus 0.03% per 5 years can be considered an upper bound in the processing scheme–induced uncertainty for global refractivity trend monitoring. Systematic errors common to all centers are not discussed in this article but are generally believed to be small.
Global and regional emissions of HFC‐125 (CHF2CF3) from in situ and air archive atmospheric observations at AGAGE and SOGE observatories
Authors: O'Doherty S. , Cunnold D. M. , Miller B. R. , Mühle J. , McCulloch A. , Simmonds P. G. , Manning A. J. , Reimann S. , Vollmer M. K. , Greally B. R. , Prinn R. G. , Fraser P. J. , Steele L. P. , Krummel P. B. , Dunse B. L. , Porter L. W. , Lunder C. R. , Schmidbauer N. , Hermansen O. , Salameh P. K. , Harth C. M. , Wang R. H. J. , Weiss R. F.
Published: December 2009

High‐frequency, in situ observations from the Advanced Global Atmospheric Gases Experiment (AGAGE) and System for Observation of halogenated Greenhouse gases in Europe (SOGE) networks for the period 1998 to 2008, combined with archive flask measurements dating back to 1978, have been used to capture the rapid growth of HFC‐125 (CHF2CF3) in the atmosphere. HFC‐125 is the fifth most abundant HFC, and it currently makes the third largest contribution of the HFCs to atmospheric radiative forcing. At the beginning of 2008 the global average was 5.6 ppt in the lower troposphere and the growth rate was 16% yr−1. The extensive observations have been combined with a range of modeling techniques to derive global emission estimates in a top‐down approach. It is estimated that 21 kt were emitted globally in 2007, and the emissions are estimated to have increased 15% yr−1 since 2000. These estimates agree within approximately 20% with values reported to the United Nations Framework Convention on Climate Change (UNFCCC) provided that estimated emissions from East Asia are included. Observations of regionally polluted air masses at individual AGAGE sites have been used to produce emission estimates for Europe (the EU‐15 countries), the United States, and Australia. Comparisons between these top‐down estimates and bottom‐up estimates based on reports by individual countries to the UNFCCC show a range of approximately four in the differences. This process of independent verification of emissions, and an understanding of the differences, is vital for assessing the effectiveness of international treaties, such as the Kyoto Protocol.
Structure-property relationship of nanocrystalline Pr2Co14B-based hard magnetic film
Authors: Zhang W. Y. , Shima H. , Takano F. , Akinaga H. , Nimori S.
Published: December 2009

Nanocrystalline Pr2Co14B-based films are deposited on two types of substrates at 600 °C by radio frequency magnetron sputtering. All samples are composed of a hard magnetic phase Pr2Co14B and a small amount of a soft magnetic phase Co3B. The film sputtered on the thermally oxidized silicon wafer has a more dispersed distribution of Co3B and a smaller average grain size of Pr2Co14B than that deposited on alumina substrates; therefore, the former film shows a stronger intergrain exchange coupling action (IECA) than the latter film. In addition, the coercivity (8.6 kOe) and ratio (0.68) of remanence to saturation magnetization of the film sputtered on thermally oxidized silicon wafers are considerably higher than those (0.4 kOe and 0.56) of the film deposited on alumina substrates. In the case of the film sputtered on alumina substrates, the size of most magnetic domains is comparable to the average grain size of magnetic phases, implying the occurrence of a weak IECA. However, in the case of the film sputtered on thermally oxidized silicon wafers, the size of most magnetic domains is considerably larger than the mean grain size of magnetic phases, indicating the occurrence of a strong IECA. The effect of the IECA on the coercivity of specimens is determined by analyzing the temperature dependence of coercivity in the framework of a nucleation model.
A method for evaluations on the radiation trapping in an inductively coupled plasma in argon
Authors: Scharwitz Christian , Makabe Toshiaki
Published: December 2009

One of the general challenges for the evaluation and interpretation of optical emission spectroscopy measurements is the occurrence of radiation trapping, which is also named self-absorption or opacity. A convenient technique to treat radiation trapping is the introduction of a parameter, which is called escape factor and gives a measure for the amount of radiation trapping. In this paper evaluations on the concept of escape factors are presented for an inductively coupled plasma in argon. Especially, the strong argon line at 811.53 nm, which arises from the transition of 2p9−1s5, is under consideration. To estimate escape factors for this line, a particular method is proposed and presented here. First experimental results are obtained under the restrictive assumptions that transitions into the resonant levels 1s2 and 1s4 are sufficiently optically thin and ratios of population densities are constant.
A method for atomic force microscopy cantilever stiffness calibration under heavy fluid loading
Authors: Kennedy Scott J. , Cole Daniel G. , Clark Robert L.
Published: December 2009

This work presents a method for force calibration of rectangular atomic force microscopy (AFM) microcantilevers under heavy fluid loading. Theoretical modeling of the thermal response of microcantilevers is discussed including a fluid-structure interaction model of the cantilever-fluid system that incorporates the results of the fluctuation-dissipation theorem. This model is curve fit to the measured thermal response of a cantilever in de-ionized water and a cost function is used to quantify the difference between the theoretical model and measured data. The curve fit is performed in a way that restricts the search space to parameters that reflect heavy fluid loading conditions. The resulting fitting parameters are used to calibrate the cantilever. For comparison, cantilevers are calibrated using Sader’s method in air and the thermal noise method in both air and water. For a set of eight cantilevers ranging in stiffness from 0.050 to 5.8 N/m, the maximum difference between Sader’s calibration performed in air and the new method performed in water was 9.4%. A set of three cantilevers that violate the aspect ratio assumption associated with the fluid loading model (length-to-width ratios less than 3.5) ranged in stiffness from 0.85 to 4.7 N/m and yielded differences as high as 17.8%.
Compact multiwire proportional counters for the detection of fission fragments
Authors: Jhingan Akhil , Sugathan P. , Golda K. S. , Singh R. P. , Varughese T. , Singh Hardev , Behera B. R. , Mandal S. K.
Published: December 2009

Two large area multistep position sensitive (two dimensional) multiwire proportional counters have been developed for experiments involving study of fission dynamics using general purpose scattering chamber facility at IUAC. Both detectors have an active area of 20×10 cm2 and provide position signals in horizontal (X) and vertical (Y) planes, timing signal for time of flight measurements and energy signal giving the differential energy loss in the active volume. The design features are optimized for the detection of low energy heavy ions at very low gas pressures. Special care was taken in setting up the readout electronics, constant fraction discriminators for position signals in particular, to get optimum position and timing resolutions along with high count rate handling capability of low energy heavy ions. A custom made charge sensitive preamplifier, having lower gain and shorter decay time, has been developed for extracting the differential energy loss signal. The position and time resolutions of the detectors were determined to be 1.1 mm full width at half maximum (FWHM) and 1.7 ns FWHM, respectively. The detector could handle heavy ion count rates exceeding 20 kHz without any breakdown. Time of flight signal in combination with differential energy loss signal gives a clean separation of fission fragments from projectile and target like particles. The timing and position signals of the detectors are used for fission coincidence measurements and subsequent extraction of their mass, angular, and total kinetic energy distributions. This article describes systematic study of these fission counters in terms of efficiency, time resolution, count rate handling capability, position resolution, and the readout electronics. The detector has been operated with both five electrode geometry and four electrode geometry, and a comparison has been made in their performances.
Toward accurate reaction energetics for molecular line growth at surface: Quantum Monte Carlo and density functional theory calculations
Authors: Kanai Yosuke , Takeuchi Noboru
Published: December 2009

We revisit the molecular line growth mechanism of styrene on the hydrogenated Si(001)2×1 surface. In particular, we investigate the energetics of the radical chain reaction mechanism by means of diffusion quantum Monte Carlo (QMC) and density functional theory (DFT) calculations. For the exchange correlation (XC) functional we use the nonempirical generalized-gradient approximation (GGA) and meta-GGA. We find that the QMC result also predicts the intra-dimer-row growth of the molecular line over the inter-dimer-row growth, supporting the conclusion based on DFT results. However, the absolute magnitudes of the adsorption/reaction energies and the heights of the energy barriers differ considerably between the QMC and DFT with the GGA/meta-GGA XC functionals.
Electrical manipulation of an electronic two-state system in Ge quantum dots
Authors: Pryor C. E. , Flatté M. E. , Levy J.
Published: December 2009

We calculate that the electronic states of strained self-assembled germanium quantum dots embedded in silicon provide a convenient two-state system for electrical control. An electronic state localized at the apex of the quantum dot is nearly degenerate with a state localized at the base of the quantum dot. Small electric fields shift the electronic ground state from apex-localized to base-localized, which permits sensitive tuning of the electronic, optical, and magnetic properties of the dot. As one example, we describe how spin-spin coupling between two germanium quantum dots can be controlled very sensitively by shifting the individual dot’s electronic ground state between apex and base.
Resonant photoacoustic cell for pulsed laser analysis of gases at high temperature
Authors: Sorvajärvi Tapio , Manninen Albert , Toivonen Juha , Saarela Jaakko , Hernberg Rolf
Published: December 2009

A new approach to high temperature gas analysis by means of photoacoustic (PA) spectroscopy is presented. The transverse modes of the resonant PA cell were excited with a pulsed laser and detected with a microphone. Changes in the properties of the PA cell resulting from a varying temperature are discussed and considered when processing the PA signal. The feasibility of the proposed method was demonstrated by studying PA response from saturated vapor of potassium chloride (KCl) in the temperature range extending from 410 to 691 °C. The PA spectrum, the detection limit, and the signal saturation of KCl vapor are discussed. At 245 nm excitation wavelength and 300 μJ pulse energy, the achieved detection limit for KCl is 15 ppb.
Low-voltage organic transistors and inverters with ultrathin fluoropolymer gate dielectric
Authors: Walser M. P. , Kalb W. L. , Mathis T. , Batlogg B.
Published: December 2009

We report on the simple fabrication of hysteresis-free and electrically stable organic field-effect transistors (OFETs) and inverters operating at voltages <1–2 V, enabled by the almost trap-free interface between the organic semiconductor and an ultrathin (<20 nm) and highly insulating single-layer fluoropolymer gate dielectric (Cytop). OFETs with PTCDI-C13 (N,N′-ditridecylperylene-3,4,9,10-tetracarboxylicdiimide) as semiconductor exhibit outstanding transistor characteristics; very low threshold voltage (0.2 V), onset at 0 V, steep subthreshold swing (0.1–0.2 V/decade), no hysteresis, and excellent stability against gate bias stress. It is gratifying to notice that such small OFET operating voltages can be achieved with the relatively simple processing techniques employed in this study.
Determination of gap defect states in organic bulk heterojunction solar cells from capacitance measurements
Authors: Boix Pablo P. , Garcia-Belmonte Germà , Muñecas Udane , Neophytou Marios , Waldauf Christoph , Pacios Roberto
Published: December 2009

Energy distributions [density-of-states (DOS)] of defects in the effective band gap of organic bulk heterojunctions are determined by means of capacitance methods. The technique consists of calculating the junction capacitance derivative with respect to the angular frequency of the small voltage perturbation applied to thin film poly(3-hexylthiophene) (P3HT) [6,6]-phenyl C61-butyric acid methyl ester (PCBM) solar cells. The analysis, which was performed on blends of different composition, reveals the presence of defect bands exhibiting Gaussian shape located at E≈0.38 eV above the highest occupied molecular orbital level of the P3HT. The disorder parameter σ, which accounts for the broadening of the Gaussian DOS, lies within the range of 49–66 meV. The total density of defects results of order 1016 cm−3.
Nonvolatile resistive switching in graphene oxide thin films
Authors: He C. L. , Zhuge F. , Zhou X. F. , Li M. , Zhou G. C. , Liu Y. W. , Wang J. Z. , Chen B. , Su W. J. , Liu Z. P. , Wu Y. H. , Cui P. , Li Run-Wei
Published: December 2009

Reliable and reproducible resistive switching behaviors were observed in graphene oxide (GO) thin films prepared by the vacuum filtration method. The Cu/GO/Pt structure showed an on/off ratio of about 20, a retention time of more than 104 s, and switching threshold voltages of less than 1 V. The switching effect could be understood by considering the desorption/absorption of oxygen-related groups on the GO sheets as well as the diffusion of the top electrodes. Our experiments indicate that GO is potentially useful for future nonvolatile memory applications.
Freestanding, bendable thin film for supercapacitors using DNA-dispersed double walled carbon nanotubes
Authors: Cooper Leora , Amano Hiroki , Hiraide Masayuki , Houkyou Satoshi , Jang In Young , Kim Yong Jung , Muramatsu Hiroyuki , Kim Jin Hee , Hayashi Takuya , Kim Yoong Ahm , Endo Morinobu , Dresselhaus Mildred S.
Published: December 2009

Freestanding, thin, and bendable electrodes for supercapacitors are fabricated by filtering DNA-dispersed double walled carbon nanotubes (DWNTs) into a thin film and thermally treating the film in argon. We found that DNA has the ability to disperse the strongly bundled DWNTs and is converted to phosphorus-enriched carbons, which give rise to strong redox peaks at around 0.4 V. The combination of the large capacitance from the DNA-derived carbons and the high electrical conductivity of carbon nanotubes allow DWNT/DNA films to be used as a potential electrode material for supercapacitors.
Stress and its effect on optical properties of AlN nanorods
Authors: Ji X. H. , Zhang Q. Y. , Ling Z. Y. , Lau S. P.
Published: December 2009

The stress states in AlN nanorods deposited on Si and its effect on optical properties have been investigated by means of Raman scattering and photoluminescence methods. The observed frequency downshift and linewidth broadening from temperature-dependent Raman scattering can be well described by an empirical relationship taking into account the contributions of the thermal expansion and decay of optical phonons. The phonon-energy difference of the E2(high) mode between the stress-free bulk-AlN and AlN nanorods appears to increase with increasing temperature, demonstrating that differential thermal expansion between the Si-substrate and AlN nanorods is the key parameter reflecting the stress in the nanorods.
Relation between critical current of domain wall motion and wire dimension in perpendicularly magnetized Co/Ni nanowires
Authors: Fukami S. , Nakatani Y. , Suzuki T. , Nagahara K. , Ohshima N. , Ishiwata N.
Published: December 2009

We investigated the relation between critical current of domain wall motion and wire dimension by using perpendicularly magnetized Co/Ni nanowires with different widths and thicknesses. The critical current, Ic, became less than 0.2 mA when w<100 nm, suggesting that magnetic random access memory with domain wall motion can replace conventional embedded memories. In addition, in agreement with theory, the critical current density, jc, decreased as wire width decreased and became much less than 5×107 A/cm2 when w<100 nm. We also performed a micromagnetic simulation and obtained good agreement between the experiment and simulation, although a few discrepancies were found.