bluuebunny/crossref_metadata_2025 huggingface dataset:
Continuous ultrasonic hydrogenation of soybean oil. II. Operating conditions and oil quality
Authors: Moulton K. J. , Koritala S. , Warner K. , Frankel E. N.
Published: July 2007

In previous work we found that ultrasonic energy greatly enhanced the rate of hydrogenation of soybean oil. We have now investigated parameters of ultrasonic hydrogenation and the quality of the resulting products. Refined and bleached soybean oil was hydrogenated continuously with and without ultrasonic energy at different temperatures, pressures and catalyst concentrations. Flavor and oxidative stability of the oils were compared with a commercially hydrogenated soybean oil. The extent of hydrogenation (ΔIV) was not affected by temperature between 245 and 290 C, but was greater at 106 psig than at 65 psig hydrogen pressure. The ΔIV of hydrogenated oils increased linearly with catalyst concentration from 40 ppm to 150 ppm nickel. At the same catalyst concentration the IV drop was significantly increased when ultrasonic energy was used. By reducing the amount of power supplied to the ultrasonic reactor to 40% of full power, the specific power (watts/ΔIV) was lowered by 60%. Linolenate selectivities and specific isomerization (%trans/ΔIV) remained the same, but linoleate selectivities were lower than for batch hydrogenation under varied operating parameters. Flavor scores were not significantly different, initially or after storage eight days at 60 C, for oils continuously hydrogenated with and without ultrasonic energy. Hydrogenation of soybean oil with ultrasonic energy offers a method to produce good quality products at potentially lower cost than present methods.
The use of atomic force microscopy to measure the formation and development of chocolate bloom in pralines
Authors: Smith Paul R. , Dahlman Annika
Published: July 2007

Atomic force microscopy (AFM) has been used to study the surface of chocolate as well as the progress of chocolate bloom over time. Fresh chocolate was found to be relatively smooth but with deep holes. These could be pipes leading deep down into the body of the chocolate, perhaps reaching the filling. After storage for a few weeks, we observed the growth of small drops around these holes. With increasing time, these drops became larger and more structured. After further storage, a crystalline structure and bloom were revealed. These results suggest that bloom growth in pralines is a two‐phase process, with drops initially forming on the surface and then bloom crystals nucleating and growing from them. Further, we deduced pipes leading down into the center of the chocolate through which the migration of filling fats can preferentially occur.
Recovery of corn oil from ethanol extracts of ground corn using membrane technology
Authors: Kwiatkowski Jason R. , Cheryan Munir
Published: July 2007

The recovery of additional co‐products from the dry‐grind process for ethanol could influence the industry greatly, as most facilities today rely on subsidies and tax incentives to operate. Modification of the process to include the extraction of oil could add $0.30–0.50 per bushel to the value derived from corn. A process combining solvent extraction with membrane technology to recover the oil was investigated. To evaluate the feasibility of this process, several nanofiltration membranes were tested for their stability in ethanol. Each of the membranes was conditioned with a solution of water/ethanol (0–100 vol/vol%) and the top three were chosen based on their performance with respect to flux and rejection. Beginning at 5 g/L, solutions of corn oil in ethanol were concentrated to over 100 g/L with the DK (Osmonics‐Desal, Minnetonka, MN), TFC‐SR1 (Koch Membrane Systems, Inc., Wilmington, MA) and TFC‐SR2 (Koch) membranes. The liquid extract was then similarly concentrated, yielding a retentate fraction that was highly concentrated with solids in addition to corn oil, such as protein (zein), lecithins, and other potentially high‐value fractions soluble in ethanol. Analysis of the extract retentate showed a significant increase in oil concentration with an increase in the volume concentration ratio, indicating that pure ethanol extracts from corn may be successfully concentrated using nanofiltration membranes.
Severely impaired left ventricular function: Tissue characterization by cardiovascular magnetic resonance in a clinical dilemma
Authors: Bucciarelli‐Ducci Chiara , Locca Didier , O'Hanlon Rory , Oldershaw Paul , Prasad Sanjay K.
Published: July 2007

In patients with symptoms of heart failure, identifying the underlying cause of cardiomyopathy is helpful to establish the diagnosis and to guide therapy. The differential diagnosis of cardiomyopathy can be challenging based on clinical findings. We report the case of a patient who represented a clinical dilemma (cardiac sarcoidosis or ischaemic heart disease), in whom cardiovascular magnetic resonance was a clinically valuable tool to distinguish dual cardiac pathology due to its unique, non‐invasive, tissue characterization capabilities.
CD248/Endosialin is dynamically expressed on a subset of stromal cells during lymphoid tissue development, splenic remodeling and repair
Authors: Lax Siân , Hou Tie Zheng , Jenkinson Eric , Salmon Mike , MacFadyen John R. , Isacke Clare M. , Anderson Graham , Cunningham Adam F. , Buckley Christopher D.
Published: July 2007

Studies of stromal cell populations in lymphoid tissue (LT) have been hampered by a lack of selective markers. Here, we show that CD248 (Endosialin/TEM1) is a stromal marker that is differentially expressed on fibroblasts and pericytes in the thymus, lymph node and spleen. Expression is high during LT development but largely disappears in the adult. CD248 is re‐expressed in a Salmonella‐induced model of splenic enlargement; peak expression corresponding to the peak of splenic enlargement. These results suggest that CD248 expression helps define a subset of LT stromal cells which play a role in remodelling during tissue development, infection and repair.
“‘Scientific’ Racism Again?”: Reginald Gates, the Mankind Quarterly and the Question of “Race” in Science after the Second World War
Authors: SCHAFFER GAVIN
Published: July 2007

Biologist and botanist Reginald Gates is mainly remembered as a staunch scientific conservative, a defender of racial theory and fierce opponent of racial mixing. In post-war Britain and America, Gates's racial views made him something of a pariah. This article explores Gates's post-war career as a micro-historical analysis of racial science and society after the Second World War. It examines the relationship between scientific racists and segregationists in the US, especially concerning the Brown ruling and the establishment of the Mankind Quarterly journal, arguing that science in this period was subsumed into politics as protagonists on both sides of the segregation debate used science to justify ideological positions.
Rememories of Nevada: Tracing Lineages of the Present
Authors: WHITE JONATHAN
Published: July 2007

“Memory mapping,” including “rememory” (as stirringly pioneered by Toni Morrison), has become crucial within the humanities. Beginning with 1950s Nevada, the present article seeks deeper rememories of the American West, then critiques more recent history. Included are responses by Native Americans, Samuel Clemens recording the goldrush era, and interpretation of McCarthyism in light of the author's family's eviction from the US. Nevada was a nuclear testing ground. “Robot” aircraft have lately been deployed from the Nellis base in delivery of Hellfire missiles in Iraq. Overall, this layering of (often violent) history is shown to support a “poetics” of cultural memory.
Race, Gender, and Space Exploration: A Chapter in the Social History of the Space Age
Authors: MCQUAID KIM
Published: July 2007

An era of space explorations and an era of expanded civil rights for racial minorities and women began simultaneously in the United States. But such important social changes are very rarely discussed in relation to each other. Four recent books on how the US astronaut program finally opened to women and minorities in 1978 address a key part of this connection, without discussing the struggles that compelled the ending of traditional race and gender exclusions. This essay examines the organizational and political dynamics of how civil rights in employment came to the US civilian space program in the decades after 1970.
Horizontal transmission success of Nosema bombi to its adult bumble bee hosts: effects of dosage, spore source and host age
Authors: RUTRECHT S. T. , KLEE J. , BROWN M. J. F.
Published: July 2007

Parasite transmission dynamics are fundamental to explaining the evolutionary epidemiology of disease because transmission and virulence are tightly linked. Horizontal transmission of microsporidian parasites, e.g. Nosema bombi, may be influenced by numerous factors, including inoculation dose, host susceptibility and host population heterogeneity. Despite previous studies of N. bombi and its bumble bee hosts, neither the epidemiology nor impact of the parasite are as yet understood. Here we investigate the influence N. bombi spore dosage (1000 to 500 000 spores), spore source (Bombus terrestris and B. lucorum isolates) and host age (2- and 10-day-old bees) have on disease establishment and the presence of patent infections in adult bumble bees. Two-day-old bees were twice as susceptible as their 10-day-old sisters, and a 5-fold increase in dosage from 100 000 to 500 000 spores resulted in a 20-fold increase in the prevalence of patent infections. While intraspecific inoculations were 3 times more likely to result in non-patent infections there was no such effect on the development of patent infections. These results suggest that host-age and dose are likely to play a role in N. bombi's evolutionary epidemiology. The relatively low levels of horizontal transmission success are suggestive of low virulence in this system.
Planning domain definition using GIPO
Authors: SIMPSON R. M. , KITCHIN D. E. , McCLUSKEY T. L.
Published: July 2007

In this paper an object-centric perspective on planning domain definition is presented along with an overview of GIPO (graphical interface for planning with objects), a supporting tools environment. It is argued that the object-centric view assists the domain developer in conceptualizing the domain’s structure, and we show how GIPO enables the developer to capture that conceptualization at an appropriate and matching conceptual level. GIPO is an experimental environment which provides a platform for exploring and demonstrating the range and scope of tools required to support the knowledge engineering aspects of creating and validating planning systems, both for classical pre-condition planning and hierarchical planning. GIPO embodies the object-centric view, leading to a range of benefits typically associated with object-oriented methods in other fields of software engineering such as highly visual development methods, code reuse and efficient, reliable development.
ARMS: an automatic knowledge engineering tool for learning action models for AI planning
Authors: WU KANGHENG , YANG QIANG , JIANG YUNFEI
Published: July 2007

We present an action model learning system known as ARMS (Action-Relation Modelling System) for automatically discovering action models from a set of successfully observed plans. Current artificial intelligence (AI) planners show impressive performance in many real world and artificial domains, but they all require the definition of an action model. ARMS is aimed at automatically learning action models from observed example plans, where each example plan is a sequence of action traces. These action models can then be used by the human editors to refine. The expectation is that this system will lessen the burden of the human editors in designing action models from scratch. In this paper, we describe the ARMS in detail. To learn action models, ARMS gathers knowledge on the statistical distribution of frequent sets of actions in the example plans. It then builds a weighted propositional satisfiability (weighted SAT) problem and solves it using a weighted MAXSAT solver. Furthermore, we show empirical evidence that ARMS can indeed learn a good approximation of the finally action models effectively.
On the Strong Chromatic Number of Random Graphs
Authors: LOH PO-SHEN , SUDAKOV BENNY
Published: July 2007

Let G be a graph with n vertices, and let k be an integer dividing n. G is said to be strongly k-colourable if, for every partition of V(G) into disjoint sets V1 ∪ ··· ∪ Vr, all of size exactly k, there exists a proper vertex k-colouring of G with each colour appearing exactly once in each Vi. In the case when k does not divide n, G is defined to be strongly k-colourable if the graph obtained by adding $k \big\lceil \frac{n}{k} \big\rceil - n$ isolated vertices is strongly k-colourable. The strong chromatic number of G is the minimum k for which G is strongly k-colourable. In this paper, we study the behaviour of this parameter for the random graph Gn,p. In the dense case when p ≫ n−1/3, we prove that the strong chromatic number is a.s. concentrated on one value Δ + 1, where Δ is the maximum degree of the graph. We also obtain several weaker results for sparse random graphs.
A Short Proof of the Hajnal–Szemerédi Theorem on Equitable Colouring
Authors: KIERSTEAD H. A. , KOSTOCHKA A. V.
Published: July 2007

A proper vertex colouring of a graph is equitable if the sizes of colour classes differ by at most one. We present a new shorter proof of the celebrated Hajnal–Szemerédi theorem: for every positive integer r, every graph with maximum degree at most r has an equitable colouring with r+1 colours. The proof yields a polynomial time algorithm for such colourings.
Parallel arterial trunks with discordant atrioventricular and concordant ventriculo-arterial connections in mirror-imaged arrangement
Authors: Ozkutlu Suheyla , Alehan Dursun
Published: July 2007

Cardiac malformations are very rare in which the great arteries arise from their appropriate ventricles, but are abnormally related to each other. Here, we present a patient with mirror-imaged atrial arrangement and a left-sided heart who has parallel arterial trunks with discordant atrioventricular and concordant ventriculo-arterial connections. The ventricles were related in supero-inferior fashion, the left ventricle being anterior and superior, this being an additional feature which, to the best of our knowledge, has not previously been described in this setting.
Can working conditions explain differences in eating patterns during working hours?
Authors: Raulio Susanna , Roos Eva , Mukala Kristiina , Prättälä Ritva
Published: July 2007

Objective

The aim of this study was to examine whether there are associations between working conditions and the use of staff canteen or packed meals among Finnish employees.

Setting

Data were obtained from cross-sectional surveys on working conditions, conducted triennially (1997, 2000, 2003) since 1997.

Subjects

In each survey, the subjects were 25–64-year-old employed Finnish employees: 3096 men and 3273 women.

Results

Employees at large workplaces used canteens far more often than those at smaller workplaces. Working conditions played a different role in canteen use at small and large workplaces, as well as among the different sexes. At small workplaces, physically demanding jobs held by female employees and low job control encouraged employees to use the canteen. On the other hand, at large workplaces, low social support at work encouraged the use of canteens among men whereas high mental strain at work meant they used the canteen less. Among women, eating packed meals was not related to working conditions, but among men, low social support and high mental strain at work were associated with more frequent use of packed meals.

Conclusions

The use of a staff canteen is largely determined by the size of the workplace and by employee education. The underlying factor could be the availability of canteens, a question which must be confirmed in further studies, since well-planned mass catering at workplaces has major effects on public health, well-being and the nutrition education of employees.
Do aggregates of multiple questions better capture overall fish consumption than summary questions?
Authors: Mina Kym , Fritschi Lin , Knuiman Matthew
Published: July 2007

Objective

To compare intake estimates, validity and reliability of two summary questions to measure fish consumption with information from a detailed semi-quantitative food-frequency questionnaire (FFQ) on fish consumption.

Design

Population-based, cross-sectional study. Participants completed an FFQ and provided blood samples for erythrocyte membrane eicosapentaenoic acid (EPA) analysis. Aggregate measures of consumption of fresh/frozen/canned fish (fresh fish) and smoked/salted/dried fish (preserved fish) were generated from the FFQ and were compared with responses to the summary questions regarding intakes of similar items. Both methods were tested for validity, using correlation and linear regression techniques with EPA, and retest reliability.

Setting

Perth metropolitan area, Western Australia.

Subjects

One hundred and nine healthy volunteers of both sexes, aged 21–75 years.

Results

The summary fresh fish measure underestimated frequency and grams per week given by the aggregate question by about 50%, while estimates from the summary preserved fish measure were approximately three times that of the aggregate measure. Multiple linear regression analysis suggested that the aggregates accounted for more of the variation in EPA levels, but the difference was minimal. Intra-class correlations confirmed that both methods were reliable.

Conclusions

Our study indicates that extensive questioning results in different absolute intakes of fish compared with brief questioning, but does not add any information if ranking individuals according to overall consumption of fish.
Nuclear winter revisited with a modern climate model and current nuclear arsenals: Still catastrophic consequences
Authors: Robock Alan , Oman Luke , Stenchikov Georgiy L.
Published: July 2007

Twenty years ago, the results of climate model simulations of the response to smoke and dust from a massive nuclear exchange between the superpowers could be summarized as “nuclear winter,” with rapid temperature, precipitation, and insolation drops at the surface that would threaten global agriculture for at least a year. The global nuclear arsenal has fallen by a factor of three since then, but there has been an expansion of the number of nuclear weapons states, with additional states trying to develop nuclear arsenals. We use a modern climate model to reexamine the climate response to a range of nuclear wars, producing 50 and 150 Tg of smoke, using moderate and large portions of the current global arsenal, and find that there would be significant climatic responses to all the scenarios. This is the first time that an atmosphere‐ocean general circulation model has been used for such a simulation and the first time that 10‐year simulations have been conducted. The response to the 150 Tg scenario can still be characterized as “nuclear winter,” but both produce global catastrophic consequences. The changes are more long‐lasting than previously thought, however, because the new model, National Aeronautics and Space Administration Goddard Institute for Space Studies ModelE, is able to represent the atmosphere up to 80 km, and simulates plume rise to the middle and upper stratosphere, producing a long aerosol lifetime. The indirect effects of nuclear weapons would have devastating consequences for the planet, and continued nuclear arsenal reductions will be needed before the threat of nuclear winter is removed from the Earth.
Stable isotope paleoaltimetry of Eocene core complexes in the North American Cordillera
Authors: Mulch A. , Teyssier C. , Cosca M. A. , Chamberlain C. P.
Published: July 2007

The hydrogen isotope composition of Eocene muscovite in mylonitic quartzite from the Kettle and Shuswap metamorphic core complexes (Washington and British Columbia) permits estimates of paleoaltimetry of the North American Cordillera at the onset of post‐collisional lithospheric extension. Coupled oxygen, hydrogen, and 40Ar/39Ar isotope data indicate that meteoric water penetrated to significant depths during normal faulting along the Columbia River Detachment bounding both Kettle and Shuswap metamorphic core complexes. Synkinematic muscovite attains δDmuscovite values as low as −135‰ and −157‰, respectively, consistent with δDwater values of −115 ± 5‰ and −135 ± 5‰. In context with stable isotope data from Eocene sedimentary basins of continental North America, these data constrain the isotopic composition of precipitation from which paleoelevation estimates can be made. Stable isotope paleoaltimetry indicates that during detachment formation (49–47 Ma), orogen‐parallel variations in topography existed, and mean elevations decreased from ≥4000 m at the latitude of the Shuswap core complex to ≥3000 m in the Kettle core complex. In addition, these data indicate a net decrease in mean surface elevation by ∼1000 m since the Eocene. Our results for the Kettle core complex are consistent with paleoelevation estimates based on fossil floral physiognomy in the Eocene Republic basin (Washington), indicating that high elevations characterized not only the frontal escarpment near the crustal‐scale detachment but continued into the Okanogan highlands further west. Collectively, the stable isotope, geochronological, and paleofloral data support tectonic models of high Eocene surface elevations contemporaneous with magmatism and lithospheric extension.
Tectonic evolution of the active Hikurangi subduction margin, New Zealand, since the Oligocene
Authors: Nicol Andrew , Mazengarb Colin , Chanier Frank , Rait Geoff , Uruski Chris , Wallace Laura
Published: July 2007

Deformation across the active Hikurangi subduction margin, New Zealand, including shortening, extension, vertical‐axis rotations, and strike‐slip faulting in the upper plate, has been estimated for the last ∼24 Myr using margin‐normal seismic reflection lines and cross sections, strike‐slip fault displacements, paleomagnetic declinations, bending of Mesozoic terranes, and seafloor spreading information. Post‐Oligocene shortening in the upper plate increased southward, reaching a maximum rate of 3–8 mm/year in the southern North Island. Upper plate shortening is a small proportion of the rate of plate convergence, most of which (>80%) accrued on the subduction thrust. The uniformity of these shortening rates is consistent with the near‐constant rate of displacement transfer (averaged over ≥5 Myr) from the subduction thrust into the upper plate. In contrast, the rates of clockwise vertical‐axis rotations of the eastern Hikurangi Margin were temporally variable, with ∼3°/Myr since 10 Ma and ∼0°–1°/Myr prior to 10 Ma. Post 10 Ma, the rates of rotation decreased westward from the subduction thrust, which resulted in the bending of the North Island about an axis at the southern termination of subduction. With rotation of the margin and southward migration of the Pacific Plate Euler poles, the component of the margin‐parallel relative plate motion increased to the present. Plate convergence dominated the Hikurangi Margin before ca. 15 Ma, with the rate of margin‐parallel motion increasing markedly since 10 Ma. Vertical‐axis rotations could accommodate all margin‐parallel motion before 1–2 Ma, eliminating the requirement for large strike‐slip displacements (for example, >50 km) in the upper plate since the Oligocene.
Mars imagery now available on the Web
Authors: Zielinski Sarah
Published: July 2007

More than 1200 images taken by the NASA Mars Reconnaissance Orbiter's High Resolution Imaging Experiment (HiRISE) camera have now been made available to the public on the Internet. HiRISE takes images of 6‐kilometer‐wide swaths of Mars, resolving features as small as 40 centimeters. The camera is expected to take images of about 1% of the planet over the next year and a half. The images—available at http://hirise.lpl.arizona.edu, a new node for NASAs Planetary Data System data archive—can be explored online with the IAS Viewer that allows for high quality images to be seen even with a slow or limited network connection.
Valle's geysers begin to reappear after landslide
Authors: Zielinski Sarah
Published: July 2007

The geysers of the Valley of the Geysers in Kamchatka, Russia, are beginning to reemerge after having become submerged following a 3 June landslide that blocked the Geyser River. The dam of mud and debris began to erode on 7 June after the river's water reached the top. This dam may not erode completely away, and would leave behind a moderately‐sized thermal lake. However, the main attractions of the valley—which is a UNESCO World site—are expected to become re‐exposed, according to the nonprofit World Wildlife Fund.
Comment on “How Nature foiled the 2006 hurricane forecasts”
Authors: Evan Amato
Published: July 2007

In a recent Eos article, Lau and Kim [2007] suggest that the increase in North Atlantic dust cover in 2006, relative to 2005, depressed ocean temperatures by as much as 1.2 K, and that this cooling was a key factor in the inaccurate forecasts for the last hurricane season. Despite the fact that tropical Atlantic Ocean temperatures in 2006 were the second highest on record and likely not the culprit for the near‐normal hurricane activity (G. Bell et al., The 2007 North Atlantic hurricane season: A climate perspective, submitted to Bulletin of the American Meteorological Society, 2007), I argue that Lau and Kim exaggerated the well‐known direct radiative forcing effect of dust on surface temperature [Miller and Tegen, 1998].
Reply to Comment on “How nature foiled the 2006 hurricane forecasts”
Authors: Lau William K. M. , Kim Kyu‐Myong
Published: July 2007

The two main objections of Evan [this issue] to our paper are that (1) the 2006 sea surface temperature (SST) in the Atlantic Ocean was actually above normal compared with the long‐term climatology, and (2) the dust radiative forcing in 2006 was not substantially greater than in 2005 and could not have caused the large change in SST.

First, we recognize that 2006 was a climatologically warm year. However, the main focus of our study was on the abrupt cooling of the Atlantic SST from 2005 to 2006, not on the long‐term variation. Hence this point is not germane to our study Second, we suggested that Saharan dust may have been important in triggering a series of rapid feedback processes in the ocean‐atmosphere system in the Atlantic in 2006 resulting in conditions that are unfavorable for hurricane formation.Therefore, the real question is, how much initial dust radiative forcing is sufficient to trigger the feedback processes? This is not a simple question to answer, because it depends on the timing of the aerosol forcing and the preexisting state of the large‐scale coupled atmosphere‐landocean system.
An appeal from the Fellows Committee
Authors: Pulkkinen Tuija
Published: July 2007

The American Geophysical Union invites nominations for the election of members to the rank of Fellow. Each year, about 100 nominations reach the Fellows Committee through the AGU Sections, and about half are elected. The number of Fellows is limited to at most .1% of the membership, which makes this honor very prestigious. The Union Fellows are distinguished scientists who have made important contributions to one or several fields of geophysical sciences. While such people often are at high positions at universities or institutions, the selection committee feels very strongly that the scientific merits are the most important criterion for fellowship. AGU has a significant number of non‐U.S. members, who at present are underrepresented in the Fellows program. I would like to invite you to consider suitable candidates amongst your colleagues and to make nominations following the instructions included in this issue.
Global distribution of seamounts from ship‐track bathymetry data
Authors: Hillier J. K. , Watts A. B.
Published: July 2007

The distribution of submarine volcanoes, or seamounts, reflects melting within the Earth and how the magma generated ascends through the overlying lithosphere. Globally (±60° latitude), we use bathymetry data acquired along 39.5 × 106 km of ship tracks to find 201,055 probable seamounts, an order of magnitude more than previous counts across a wider height‐range (0.1 < h < 6.7 km). In the North Pacific, seamounts' spatial distribution substantially reflects ridge‐crest conditions, variable on timescales of 10 s of Ma and along‐ridge distances of ∼1,000 km, rather than intra‐plate hot‐spot related volcanic activity. In the Atlantic, volcano numbers decrease, somewhat counter‐intuitively, towards Iceland suggesting that abundant under‐ridge melt may deter the formation of isolated volcanoes. Neither previously used empirical curve (exponential or power‐law) describes the true size‐frequency distribution of seamounts. Nevertheless, we predict 39 ± 1 × 103 large seamounts (h > 1 km), implying that ∼24,000 (60%) remain to be discovered.
Sulfur and phosphorus in the Earth's core: The Fe‐P‐S system at 23 GPa
Authors: Stewart A. J. , Schmidt M. W.
Published: July 2007

Phosphorus is an important element believed to be present in the Earth's core. As a non‐metal, its solubility in iron is limited, leading to the precipitation of phosphides at high concentrations. Here we present experimental results for the iron‐rich portions of the Fe‐P and Fe‐P‐S systems at 23 GPa. We find a Fe‐P eutectic point occurring at 9 wt% P and 1275°C at 23 GPa. Up to 4 wt% P is soluble in the Fe‐rich solid coexisting with the eutectic liquid at these conditions. The ternary Fe‐P‐S system displays a simple cotectic between the Fe‐P and Fe‐S binary eutectics with minimum melting temperature on the S‐side at 1075°C. At subsolidus conditions there is complete solid solution between Fe3P and Fe3S. The high solubility of phosphorus in iron along with its miscibility in Fe3S and iron‐sulfur liquids at high pressures, combined with expectation of only minor concentrations in planetary cores, indicate phosphorus will not form a distinct phase within terrestrial planet cores.
Understanding of slip‐weakening and ‐strengthening in a single framework of modeling and its seismological implications
Authors: Suzuki Takehito , Yamashita Teruo
Published: July 2007

We theoretically study dynamic fault slip taking account of thermoporoelastic effects including inelastic porosity change; the porosity on the fault is assumed to increase inelastically with increasing fault slip. We find in the analysis of a 1D fault model that qualitative nature of system behavior is controlled by a single nondimensional parameter Su, a quantity proportional to the increase rate of inelastic porosity divided by the thickness of shear heating zone. The change of value of Su is found to cause slip‐weakening as well as slip‐strengthening. It is reported in some studies that the radiation efficiency estimated seismologically exceeds unity for some earthquakes, which contradicts its definition. This paradox can be solved if we assume a relatively large Su value for these earthquakes.
A study of secondary organic aerosol formation in the anthropogenic‐influenced southeastern United States
Authors: Weber Rodney J. , Sullivan Amy P. , Peltier Richard E. , Russell Armistead , Yan Bo , Zheng Mei , de Gouw Joost , Warneke Carsten , Brock Charles , Holloway John S. , Atlas Elliot L. , Edgerton Eric
Published: July 2007

The formation of secondary organic aerosol (SOA) in an anthropogenic‐influenced region in the southeastern United States is investigated by a comparison with urban plumes in the northeast. The analysis is based on measurements of fine‐particle organic compounds soluble in water (WSOC) as a measure of secondary organic aerosol. Aircraft measurements over a large area of northern Georgia, including the Atlanta metropolitan region, and in plumes from New York City and surrounding urban regions in the northeast show that fine‐particle WSOC are spatially correlated with vehicle emission tracers (e.g., CO), yet the measurements indicate that vehicles do not directly emit significant particulate WSOC. In addition to being correlated, WSOC concentrations were in similar proportions to anthropogenic tracers in both regions, despite biogenic volatile organic compounds (VOCs) that were on average 10–100 times higher over northern Georgia. In contrast, radiocarbon analysis on WSOC extracted from integrated filters deployed in Atlanta suggests that roughly 70–80% of the carbon in summertime WSOC is modern. If both findings are valid, the combined results indicate that in northern Georgia, fine‐particle WSOC was secondary and formed through a process that involves mainly modern biogenic VOCs but which is strongly linked to an anthropogenic component that may largely control the mass of SOA formed. Independent of the radiocarbon results, a strong association between SOA and anthropogenic sources has implications for control strategies in urban regions with large biogenic VOC emissions.
Sequence-based analysis of pQBR103; a representative of a unique, transfer-proficient mega plasmid resident in the microbial community of sugar beet
Authors: Tett Adrian , Spiers Andrew J , Crossman Lisa C , Ager Duane , Ciric Lena , Dow J Maxwell , Fry John C , Harris David , Lilley Andrew , Oliver Anna , Parkhill Julian , Quail Michael A , Rainey Paul B , Saunders Nigel J , Seeger Kathy , Snyder Lori A S , Squares Rob , Thomas Christopher M , Turner Sarah L , Zhang Xue-Xian , Field Dawn , Bailey Mark J
Published: July 2007

The plasmid pQBR103 was found within Pseudomonas populations colonizing the leaf and root surfaces of sugar beet plants growing at Wytham, Oxfordshire, UK. At 425 kb it is the largest self-transmissible plasmid yet sequenced from the phytosphere. It is known to enhance the competitive fitness of its host, and parts of the plasmid are known to be actively transcribed in the plant environment. Analysis of the complete sequence of this plasmid predicts a coding sequence (CDS)-rich genome containing 478 CDSs and an exceptional degree of genetic novelty; 80% of predicted coding sequences cannot be ascribed a function and 60% are orphans. Of those to which function could be assigned, 40% bore greatest similarity to sequences from Pseudomonas spp, and the majority of the remainder showed similarity to other γ-proteobacterial genera and plasmids. pQBR103 has identifiable regions presumed responsible for replication and partitioning, but despite being tra+ lacks the full complement of any previously described conjugal transfer functions. The DNA sequence provided few insights into the functional significance of plant-induced transcriptional regions, but suggests that 14% of CDSs may be expressed (11 CDSs with functional annotation and 54 without), further highlighting the ecological importance of these novel CDSs. Comparative analysis indicates that pQBR103 shares significant regions of sequence with other plasmids isolated from sugar beet plants grown at the same geographic location. These plasmid sequences indicate there is more novelty in the mobile DNA pool accessible to phytosphere pseudomonas than is currently appreciated or understood.
Pyrosequencing enumerates and contrasts soil microbial diversity
Authors: Roesch Luiz F W , Fulthorpe Roberta R , Riva Alberto , Casella George , Hadwin Alison K M , Kent Angela D , Daroub Samira H , Camargo Flavio A O , Farmerie William G , Triplett Eric W
Published: July 2007

Estimates of the number of species of bacteria per gram of soil vary between 2000 and 8.3 million (Gans et al., 2005; Schloss and Handelsman, 2006). The highest estimate suggests that the number may be so large as to be impractical to test by amplification and sequencing of the highly conserved 16S rRNA gene from soil DNA (Gans et al., 2005). Here we present the use of high throughput DNA pyrosequencing and statistical inference to assess bacterial diversity in four soils across a large transect of the western hemisphere. The number of bacterial 16S rRNA sequences obtained from each site varied from 26 140 to 53 533. The most abundant bacterial groups in all four soils were the Bacteroidetes, Betaproteobacteria and Alphaproteobacteria. Using three estimators of diversity, the maximum number of unique sequences (operational taxonomic units roughly corresponding to the species level) never exceeded 52 000 in these soils at the lowest level of dissimilarity. Furthermore, the bacterial diversity of the forest soil was phylum rich compared to the agricultural soils, which are species rich but phylum poor. The forest site also showed far less diversity of the Archaea with only 0.009% of all sequences from that site being from this group as opposed to 4%–12% of the sequences from the three agricultural sites. This work is the most comprehensive examination to date of bacterial diversity in soil and suggests that agricultural management of soil may significantly influence the diversity of bacteria and archaea.
Hydride transfer reaction dynamics of OD++C3H6
Authors: Liu Li , Richards Elizabeth S. , Farrar James M.
Published: July 2007

The hydride transfer reaction between OD+ and C3H6 has been studied experimentally and theoretically over the center of mass collision energy range from 0.21to0.92eV using the crossed beam technique and density functional theory calculations. The center of mass flux distributions of the product ions at three different energies are highly asymmetric, with maxima close to the velocity and direction of the precursor propylene beam, characteristic of direct reactions. In the hydride transfer process, the entire reaction exothermicity is transformed into product internal excitation, consistent with mixed energy release in which the hydride ion is transferred with both the breaking and forming bonds extended. At higher collision energies, at least 85% of the incremental translational energy appears in product translation, providing a clear example of induced repulsive energy release. Compared to the related reaction of OD+ with C2H4, reaction along the pathway initiated by addition of OD+ to the CC bond in propylene has a critical bottleneck caused by the torsional motion of the methyl substituent on the double bond. This bottleneck suppresses reaction through an intermediate complex in favor of direct hydride abstraction. Hydride abstraction appears to be a sequential process initiated by electron transfer in the triplet manifold, followed by rapid intersystem crossing and subsequent hydrogen atom transfer to form ground state allyl cation and HOD.
Interaction of oxygen with TiN(001):N↔O exchange and oxidation process
Authors: Graciani J. , Fdez Sanz J. , Asaki T. , Nakamura K. , Rodriguez J. A.
Published: July 2007

This work presents a detailed experimental and theoretical study of the oxidation of TiN(001) using a combination of synchrotron-based photoemission and density functional theory (DFT). Experimentally, the adsorption of O2 on TiN(001) was investigated at temperatures between 250 and 450K. At the lowest temperature, there was chemisorption of oxygen (O2,gas→2Oads) without significant surface oxidation. In contrast, at 450K the amount of O2 adsorbed increased continuously, there was no evidence for an oxygen saturation coverage, a clear signal in the Ti 2p core level spectra denoted the presence of TiOx species, and desorption of both N2 and NO was detected. The DFT calculations show that the adsorption/dissociation of O2 is highly exothermic on a TiN(001) substrate and is carried out mainly by the Ti centers. A high oxygen coverage (larger than 0.5 ML) may induce some structural reconstructions of the surface. The exchange of a surface N atom by an O adatom is a highly endothermic process (ΔE=2.84eV). However, the overall oxidation of the surface layer is thermodynamically favored due to the energy released by the dissociative adsorption of O2 and the formation of N2 or NO. Both experimental and theoretical results lead to conclude that a TiN+mO2→TiOx+NO reaction is an important exit channel for nitrogen in the oxidation process.
Spontaneous self-assembly process for threadlike micelles
Authors: Arai Noriyoshi , Yasuoka Kenji , Masubuchi Yuichi
Published: July 2007

More than 100μs dissipative particle dynamics simulations were carried out to investigate the spontaneous formation process of threadlike micelles from the random configuration for surfactant molecules. Stable spherical micelles were formed during the earlier stage. These spherical micelles fused to each other and grew into rodlike and threadlike micelles during the later stage. The length and radius of a micelle were estimated by tracing the backbone positions and the distance between the head group particles and the backbone of the micelles, respectively. The ratio of the largest to the smallest principal moments of inertia for each micelle was calculated as the micelle shape.
Fixed charge density in dielectrics deposited on c-Si using space charge region dominated lifetime measurements
Authors: Garín M. , Martín I. , Bermejo S. , Alcubilla R.
Published: July 2007

Depletion region modulation (DRM) effect is often observed in photoconductance lifetime measurements of crystalline silicon wafers passivated by dielectric films. This effect is closely related to the space-charge region electrostatically induced by fixed charges within the dielectric. This study proposes a model for dielectric-passivated c-Si wafers, which includes the DRM effect, to simulate and fit the effective lifetime vs excess minority carrier density curves obtained by quasisteady-state photoconductance techniques. The validity of the model is checked by applying it to different experimental samples, taking particular care of the mobility values of the surface carriers. It is, thus, demonstrated that the fixed charge within the dielectric film can be determined with improved accuracy and increased reliability if the DRM effect is included into the model.
Cutting process dynamics by nonlinear time series and wavelet analysis
Authors: Sen Asok K. , Litak Grzegorz , Syta Arkadiusz
Published: July 2007

We have modeled the dynamics of a cutting process by a two-degree-of-freedom mass-spring system with dry friction. Using nonlinear time series and wavelet analysis, we have investigated the vibrational instabilities of the system for different values of the cutting force. By constructing the phase portraits and calculating the Lyapunov exponents we have delineated the conditions for which a periodic or chaotic motion can occur. The results are verified by means of a time-scale representation of the wavelet power spectrum.
Aberration-corrected multipole Wien filter for energy-filtered x-ray photoemission electron microscopy
Authors: Niimi Hironobu , Chun Wang-Jae , Suzuki Shushi , Asakura Kiyotaka , Kato Makoto
Published: July 2007

The aberration of a multipole Wien filter for energy-filtered x-ray photoemission electron microscopy was analyzed and the optimized Fourier components of the electric and magnetic fields for the third-order aperture aberration corrections were obtained. It was found that the third-order aperture aberration correction requires 12 electrodes and magnetic poles.
Pressure/mass method to measure open porosity of porous solids
Authors: Salissou Y. , Panneton R.
Published: July 2007

This work presents a method to directly determine the open porosity of porous solids, and more particularly those used in sound absorbing liners. The method is based on the measurement of four masses at four static pressures from which the open porosity and true mass density are deduced using the perfect gas law. The precision of the method in relation with the used experimental setup is studied, and a simple expression is derived to predict the experimental error in function of the bulk volume of the sample to test. For a given experimental setup, this simple expression can be used to select the amount of bulk volume to test to reach a given precision. The method and its error prediction are tested experimentally on different samples of theoretically known open porosity. Good correlations are obtained for low and high porosity samples.
Theoretical investigation of electronic structures and excitation energies of doubly N-confused porphyrin and its group 11 transition metal (III) complexes
Authors: Zhu Yulan , Zhou Shuyu , Kan Yuhe , Yan Likai , Su Zhongmin
Published: July 2007

Density functional theory is carried out to study cis-doubly N-confused porphyrin and its metal (Cu3+, Ag3+, and Au3+) complexes. The electronic structures and bonding situations of these molecules have been investigated by using the natural bond orbital analysis and the topological analysis of the electron localization function. We have studied the electronic spectra of cis-doubly N-confused porphyrin and its metal complexes with time-dependent density functional theory. The introduction of group 11 transition metals leads to blueshifts of their electronic spectra with respect to that of cis-doubly N-confused porphyrin. In particular, the absorption spectra of the copper complex show some weak Q bands that mainly arise from a combination of ligand-to-metal charge transfer and ligand-to-ligand charge transfer transitions. The relativistic time-dependent density functional theory with spin-orbit coupling calculations indicates that the effects of spin-orbit coupling on the excitation energies of the copper and silver complexes are so small that it is safe enough to neglect spin-orbit interactions for these two complexes. However, it has a significant effect on the absorption spectra of the gold complex.
Implant damage and strain relaxation of embedded epitaxial silicon germanium layer on silicon
Authors: Liu J. P. , Li J. , See A. , Zhou M. S. , Hsia L. C.
Published: July 2007

The authors report on the implant damage and strain relaxation in embedded silicon germanium (SiGe) layer, selectively grown on recessed silicon (Si) (001) with different recess length (defined as [110] direction, along the conventional Si transistor channel) and the same width (defined as [1−10] direction). Similar to the implant damage in blanket epi-SiGe layers on Si (001) reported previously, they observed two defect bands, one close to the surface and the other at SiGe∕Si interface. Unlike the biaxial strain relaxation with misfit dislocations equally distributed along both the [110] and [1−10] directions in blanket epi-SiGe layers on Si (001), there is a gradual change from biaxial to uniaxial relaxation with misfit dislocations along only at the [1−10] direction and a decreasing density of misfit dislocation, with decreasing recess length.
Near-edge optical absorption behavior of sputter deposited hafnium dioxide
Authors: Hoppe E. E. , Sorbello R. S. , Aita C. R.
Published: July 2007

The absorption behavior at the onset of the ultraviolet optical edge of sputter deposited hafnium dioxide is reported. X-ray diffraction showed that films grown at room temperature on fused silica were nanocrystalline monoclinic, and that after air annealing at 1273 K for 24 h, they were well-crystallized monoclinic with a strong (11–1) texture. Spectrophotometry was used to measure transmission and reflection in the 190–1100 nm wavelength range. The absorption coefficient, α(E), as a function of energy, E, was determined from spectrophotometric data. Two persistent features were identified. Feature I is the rapid rise in α(E) above 6.24 eV that is unchanged upon annealing. A linear α(E)1/2 vs E dependence associates this feature with indirect interband transitions. Feature II initiates at ∼5.65 eV and saturates at 5.94 eV. It appears as a low energy shoulder on the absorption edge of the as-grown films and develops into a discrete and more intense band in the annealed films, in which the coordination of Hf with seven O is satisfied. Its annealing behavior explicitly shows that feature II is not caused by an O defect, but is intrinsic to monoclinic HfO2.