bluuebunny/crossref_metadata_2025 huggingface dataset:
Negotiation, Trade and the Rituals of Encounter: An Examination of the Slave-Trading Voyage of De Zon, 1775–1776
Authors: Alexander Andrew
Published: March 2010

The intention of this paper is to fill a gap in a rich yet underrepresented aspect of Indian Ocean slave history. I have elected to found this study on a close reading of a journal from a slave-trading vessel that sought slaves for the Cape in Madagascar in the mid-1770s. This vessel, De Zon, conducted a slave-trading operation on behalf of the VOC along the west coast of Madagascar from May 1775 to January 1776. I have undertaken a close reading of the journal maintained by the merchant of De Zon, so as to write a history sensitive to the daily experiences of the slave traders in Madagascar, as well as to the codes and discourse through which this experience was filtered.

This paper is primarily concerned with the experience of negotiation and trading as it was recorded by the VOC merchants on the vessels, and is drawn predominantly from the first trading encounter of the crew of De Zon when they arrived in Madagascar in 1775. In contrast to the surveys that comprise the majority of the English-language scholarship on slave trading in Madagascar, this paper is founded on a close reading of particular episodes; it thus represents an attempt at a micronarrative that illustrates and details the historical experience of VOC slave trading on the island at a particular juncture.
Mare Liberumin the West Indies?: Hugo Grotius and the Case of theSwimming Lion, a Dutch Pirate in the Caribbean at the Turn of the Seventeenth Century
Authors: van Ittersum Martine Julia
Published: March 2010

This article reconstructs the voyage of theSwimming Lionto the Caribbean in 1595 and the court battle to which it gave rise. The Master mariner Gillis Dorenhoven was accused of piracy by Pedro d'Arana,contadorof Havana, who sued his employers before the Middelburg Admiralty Court in 1609–1610. Johan Boreel, the eldest son of one of the defendants, sought expert advice from his friend Hugo Grotius. The author ofMare Liberum, published in April 1609, became involved in the case at various levels. Pressure was put on the States General to revise their instructions for the Admiralty Court. Grotius also tried to convince the Admiralty judges that freedom of trade and navigation was a fundamental right of Dutch merchants in the West Indies and that Dorenhoven's actions should be seen in this light. For political reasons, he could not refer to the Americas inMare Liberum. Yet the case of theSwimming Lionreveals just how expansive his notion of freedom of trade and navigation really was.
Environmental Conservation and Deforestation in British India 1855–1947: A Reinterpretation
Authors: Barton Gregory A. , Bennett Brett M.
Published: March 2010

The history of forestry in British India has evoked a wide range of responses from environmental historians. Debates often centre in particular on the ethic of the bureaucratic organisation responsible for managing the government-controlled forests of India: the Indian Forest Service. Born on the subcontinent and rooted in the European scientific tradition, the Indian Forest Service model, or “empire forestry” as it came to be called from the 1920s onward, has been described as a first step in the world-wide environmental movement or, alternately, as the culprit responsible for widespread deforestation of the subcontinent. This article will address a key aspect of the debate over the Indian Forest Service (hereafter referred to as the IFS) that has profound implications for our understanding of the relationship -between imperialism and forestry conservation. By examining the tension between conservation-minded foresters who battled against timber companies and economically focused imperial bureaucrats, we answer the following question: did the IFS develop a legacy of deforestation throughout the subcontinent between 1855 and 1947? We conclude that the IFS did not develop a dominant ethic of resource exploitation, nor did the IFS rapidly accelerate the rates of deforestation during the colonial period. Rather, the IFS provided a powerful and persuasive counterweight to gentleman capitalists and economically oriented administrators who strenuously battled for more extensive exploitation of forest resources.
“Galanterie di cose rare…”: Filippo Sassetti's Indian Shopping List for the Medici Grand Duke Francesco and His Brother Cardinal Ferdinando
Authors: Karl Barbara
Published: March 2010

Between 1584 and 1588, the Florentine merchant Filippo Sassetti sent a whole sequence of letters from India to his friends and the grand ducal court in Florence. He informed his correspondents about local Indian plants, animals, the mechanisms of commercial exchange and Indian social structures and politics. Apart from publishing and editing letters, the scholarship so far has focused on linguistic, geographic, medical and ethnographical issues related to his letters. This article focuses on a set of rarely explored resources: the valuable objects sent with Sassetti's letters to the grand duke Francesco de Medici (1541–87) and his brother cardinal Ferdinando (1549–1609). The letters are exceptional, since they allow one to reconstruct the origins and itineraries of the items that Sassetti describes in detail. None of the objects survived in Florence but some of them are traceable to the Medici inventories of the sixteenth century.
Parental numeric language input to Mandarin Chinese and English speaking preschool children
Authors: CHANG ALICIA , SANDHOFER CATHERINE M. , ADELCHANOW LAUREN , ROTTMAN BENJAMIN
Published: March 2010

The present study examined the number-specific parental language input to Mandarin- and English-speaking preschool-aged children. Mandarin and English transcripts from the CHILDES database were examined for amount of numeric speech, specific types of numeric speech and syntactic frames in which numeric speech appeared. The results showed that Mandarin-speaking parents talked about number more frequently than English-speaking parents. Further, the ways in which parents talked about number terms in the two languages was more supportive of a cardinal interpretation in Mandarin than in English. We discuss these results in terms of their implications for numerical understanding and later mathematical performance.
Morphosyntactic annotation of CHILDES transcripts
Authors: SAGAE KENJI , DAVIS ERIC , LAVIE ALON , MACWHINNEY BRIAN , WINTNER SHULY
Published: March 2010

Corpora of child language are essential for research in child language acquisition and psycholinguistics. Linguistic annotation of the corpora provides researchers with better means for exploring the development of grammatical constructions and their usage. We describe a project whose goal is to annotate the English section of the CHILDES database with grammatical relations in the form of labeled dependency structures. We have produced a corpus of over 18,800 utterances (approximately 65,000 words) with manually curated gold-standard grammatical relation annotations. Using this corpus, we have developed a highly accurate data-driven parser for the English CHILDES data, which we used to automatically annotate the remainder of the English section of CHILDES. We have also extended the parser to Spanish, and are currently working on supporting more languages. The parser and the manually and automatically annotated data are freely available for research purposes.
Campylobacteriosis outbreak associated with ingestion of mud during a mountain bike race
Authors: STUART T. L. , SANDHU J. , STIRLING R. , CORDER J. , ELLIS A. , MISA P. , GOH S. , WONG B. , MARTIQUET P. , HOANG L. , GALANIS E.
Published: March 2010

One of the largest reported campylobacteriosis outbreaks in Canada occurred in June 2007 in British Columbia, associated with a mountain bike race that took place in muddy conditions. A retrospective cohort study was conducted and environmental samples were collected and tested. There were 537 racers included in the study and 225 racers (42%) reported diarrhoeal illness after the race.C. jejuniclinical isolates (n=14) were found to be identical by multi-locus sequence typing. Although univariate analysis suggested water consumption and mud exposure as significant risk factors, multivariate analysis revealed that on direct ingestion mud was significantly associated with illness (OR 4·08, 95% CI 2·03–8·21). Contaminated mud was thus the most likely source ofCampylobacterinfection. We identified other unpublished reports of outbreaks associated with bike races in rainy or muddy conditions; these underscore the importance of educating racers and raising public awareness of the risks of mud ingestion.
Characteristics of norovirus gastroenteritis outbreaks in a psychiatric centre
Authors: TSENG C. Y. , CHEN C. H. , SU S. C. , WU F. T. , CHEN C. C. , HSIEH G. Y. , HUNG C. H. , FUNG C. P.
Published: March 2010

Noroviruses are an important aetiological agent of acute gastroenteritis. They are responsible for large outbreaks of disease in the community, hospitals and long-term-care facilities. The clinical manifestations of norovirus outbreaks in psychiatric units are rarely described. The disease burden and impact highlight the importance of timely notification and investigation of these outbreaks. We analysed the characteristics of four norovirus outbreaks which occurred during a 3-year period in an in-patient psychiatric care unit. A total of 184 patients were affected which included 172 hospitalized patients, seven healthcare workers (HCWs) and five psychiatric nursing-home residents. The mean incidence rate of norovirus gastroenteritis (NVG) in hospitalized patients during these outbreaks was 12·7%. These outbreaks were characterized by higher incidence in middle-aged male patients, predominant sickness of diarrhoea, short duration of illness, peaks in late winter and early spring, and higher susceptibility in acute psychiatric patients. HCWs had longer duration of illness than psychiatric patients. More than 10% of affected patients experienced ⩾2 infections. Infection control measures were instituted and a comprehensive, responsive standard operating procedure for NVG and outbreak management was developed. After implementation of these measures, no further outbreaks of NVG occurred during the study period.
Human papillomavirus vaccination and social inequality: results from a prospective cohort study
Authors: ROBERTS S. A. , BRABIN L. , STRETCH R. , BAXTER D. , ELTON P. , KITCHENER H. , McCANN R.
Published: March 2010

We investigated the effect of social inequalities on the uptake of human papillomavirus (HPV) vaccination, combining data from a feasibility study conducted in 2007–2008 in 2817 secondary schoolgirls in two UK primary-care trusts, with census and child health records. Uptake was significantly lower in more deprived areas (P<0·001) and in ethnic minority girls (P=0·013). The relatively small proportion of parents who actively refused vaccination by returning a negative consent form were more likely to come from more advantaged areas (P<0·001). Non-responding parents were from more deprived (P<0·001) and ethnic minority (P=0·001) backgrounds. Girls who did not receive HPV vaccination were less likely to have received all their childhood immunizations particularly measles, mumps and rubella (MMR). Different approaches may be needed to maximize HPV vaccine uptake in engaged and non-responding parents, including ethnic-specific approaches for non-responders.
Preface for the special issue on domains
Authors: REUS BERNHARD , JUNG ACHIM , KEIMEL KLAUS , STREICHER THOMAS
Published: March 2010

This special issue of Mathematical Structures in Computer Science contains six papers from the Workshop on Domains IX held at the University of Sussex (Brighton), on 22–24 September 2008. This was the ninth event in the long tradition of Domains workshops, which started in Darmstadt in 1994. Since then, workshops have been organised in Braunschweig (1996), Munich (1997), Siegen (1998), Darmstadt again (1999, 2004), Birmingham (2002) and Novosibirsk (2007).
Selection functions, bar recursion and backward induction
Authors: ESCARDÓ MARTÍN , OLIVA PAULO
Published: March 2010

Bar recursion arises in constructive mathematics, logic, proof theory and higher-type computability theory. We explain bar recursion in terms of sequential games, and show how it can be naturally understood as a generalisation of the principle of backward induction that arises in game theory. In summary, bar recursion calculates optimal plays and optimal strategies, which, for particular games of interest, amount to equilibria. We consider finite games and continuous countably infinite games, and relate the two. The above development is followed by a conceptual explanation of how the finite version of the main form of bar recursion considered here arises from a strong monad of selections functions that can be defined in any cartesian closed category. Finite bar recursion turns out to be a well-known morphism available in any strong monad, specialised to the selection monad.
De Groot duality and models of choice: angels, demons and nature
Authors: GOUBAULT-LARRECQ JEAN
Published: March 2010

We introduce convex–concave duality for various models of non-deterministic choice, probabilistic choice and the two of them combined. This complements the well-known duality of stably compact spaces in a pleasing way: convex–concave duality swaps angelic and demonic choice, and leaves probabilistic choice invariant.
SMALE’S PROBLEM FOR CRITICAL POINTS ON CERTAIN TWO RAYS
Authors: HINKKANEN AIMO , KAYUMOV ILGIZ
Published: March 2010

Let f be a polynomial of degree n≥2 with f(0)=0 and f′(0)=1. We prove that there is a critical point ζ of f with ∣f(ζ)/ζ∣≤1/2 provided that the critical points of f lie in the sector {reiθ:r>0,∣θ∣≤π/6}, and ∣f(ζ)/ζ∣<2/3 if they lie in the union of the two rays {1+re±iθ:r≥0}, where 0<θ≤π/2.
A NOTE ON SIMULTANEOUS CONGRUENCES, II: MORDELL REVISED
Authors: WOOLEY TREVOR D.
Published: March 2010

When p is a prime number, and k1,…,kt are natural numbers with 1≤k1<k2<⋯<kt<p, we show that the simultaneous congruences ∑ t1xkji≡∑ t1ykjimod p (1≤j≤t) possess at most k1⋯ktpt solutions with 1≤xi,yi≤p (1≤i≤t). Analogous conclusions are provided when one or more of the exponents ki is negative.
Food security in the context of energy and resource depletion: Sustainable agriculture in developing countries
Authors: Flora Cornelia Butler
Published: March 2010

Food insecurity remains high in most of sub-Saharan African. That insecurity is made even more acute by the increasing scarcity and degradation of natural resources. Low soil fertility is a consistent problem faced by agriculturalists and herders. The dominant international thrust to increase food production has been to stimulate trade, enhanced by technology and its transfer. While international bodies acknowledge the importance of small farmers, they operate as if improving the technologies, trade regimes and value chains that are characteristic of industrial agriculture will have the same results in local ecosystems in developing countries. Price volatility makes access to purchased inputs more risky for smallholders and the governments that subsidize those inputs. The diverse local contexts that serve as the base of African agriculture are thus assumed to be overridden by technology. In contrast, a systems approach that focuses on sustainability of the local ecosystem, social and cultural relationships and economic security can be as, or more productive than industrial agriculture and have a much better opportunity to increase food security in developing countries. Such a systems-based shift in practices, such as the application of conservation agriculture and integrated systemic approaches in Millennium Villages, have potential of addressing household livelihood strategies and production issues in a sustainable, farmer-based way. Resource-conserving agriculture has been shown to increase yields in developing countries. Priority should be given to developing technologies that follow the systems principles of sustainable agriculture, integrating biological and ecological processes (such as nutrient cycling, nitrogen fixation, soil regeneration and biodiversity) into the production processes; minimizing use of non-renewable inputs that cause harm to the environment or to the health of farmers and consumers; and making productive use of the knowledge and skills of farmers and their collective capacities to work together to solve common problems. A variety of models are on the ground in Africa, and there is political will in the African Union to increase investment in agriculture. What sort of investments, policy interventions and capacity building are more effective in increasing productivity and the well-being of agricultural producers? Are strategies aimed at reducing the number of people involved in farming and herding viable in the context of a stagnant world economy?
Comparing “Visual” Effect Size Indices for Single-Case Designs
Authors: Manolov Rumen , Solanas Antonio , Leiva David
Published: March 2010

Effect size indices are indispensable for carrying out meta-analyses and can also be seen as an alternative for making decisions about the effectiveness of a treatment in an individual applied study. The desirable features of the procedures for quantifying the magnitude of intervention effect include educational/clinical meaningfulness, calculus easiness, insensitivity to autocorrelation, low false alarm, and low miss rates. Three effect size indices related to visual analysis are compared according to the aforementioned criteria. The comparison is made by means of data sets with known parameters: degree of serial dependence, presence or absence of general trend, and changes in level and/or in slope. The percent of nonoverlapping data showed the highest discrimination between data sets with and without intervention effect. In cases when autocorrelation or trend is present, the percentage of data points exceeding the median may be a better option to quantify the effectiveness of a psychological treatment.
Northern Rocky Mountain streamflow records: Global warming trends, human impacts or natural variability?
Authors: St. Jacques Jeannine‐Marie , Sauchyn David J. , Zhao Yang
Published: March 2010

The ∼60 year Pacific Decadal Oscillation (PDO) is a major factor controlling streamflow in the northern Rocky Mountains, causing dryness during its positive phase, and wetness during its negative phase. If the PDO’s influence is not incorporated into a trend analysis of streamflows, it can produce detected declines that are actually artifacts of this low‐frequency variability. Further difficulties arise from the short length and discontinuity of most gauge records, human impacts, and residual autocorrelation. We analyze southern Alberta and environs instrumental streamflow data, using void‐filled datasets from unregulated and regulated gauges and naturalized records, and Generalized Least Squares regression to explicitly model the impacts of the PDO and other climate oscillations. We conclude that streamflows are declining at most gauges due to hydroclimatic changes (probably from global warming) and severe human impacts, which are of the same order of magnitude as the hydroclimate changes, if not greater.
Mass transport induced by internal Kelvin waves beneath shore‐fast ice
Authors: Støylen Eivind , Weber Jan Erik H.
Published: March 2010

A one‐layer reduced‐gravity model is used to investigate the wave‐induced mass flux in internal Kelvin waves along a straight coast beneath shore‐fast ice. The waves are generated by barotropic tidal pumping at narrow sounds, and the ice lid introduces a no‐slip condition for the horizontal wave motion. The mean Lagrangian fluxes to second order in wave steepness are obtained by integrating the equations of momentum and mass between the material interface and the surface. The mean flow is forced by the conventional radiation stress for internal wave motion, the mean pressure gradient due to the sloping surface, and the frictional drag at the boundaries. The equations that govern the mean fluxes are expressed in terms of mean Eulerian variables, while the wave forcing terms are given by the horizontal divergence of the Stokes flux. Analytical results show that the effect of friction induces a mean Eulerian flux along the coast that is comparable to the Stokes flux. In addition, the horizontal divergence of the total mean flux along the coast induces a small mass flux in the cross‐shore direction. This flux changes the mean thickness of the upper layer outside the trapping region and may facilitate geostrophically balanced boundary currents in enclosed basins. This is indeed demonstrated by numerical solutions of the flux equations for confined areas larger than the trapping region. Application of the theory to Arctic waters is discussed, with emphasis on the transport of biological material and pollutants in nearshore regions.
Composition and genetic diversity of picoeukaryotes in subtropical coastal waters as revealed by 454 pyrosequencing
Authors: Cheung Man Kit , Au Chun Hang , Chu Ka Hou , Kwan Hoi Shan , Wong Chong Kim
Published: March 2010

Information on genetic diversity of picoeukaryotes (<2–3 μm) comes mainly from traditional gene cloning and sequencing, but this method suffers from cloning biases and limited throughput. In this study, we explored the feasibility of using the cloning-independent and massively parallel 454 pyrosequencing technology to study the composition and genetic diversity of picoeukaryotes in the coastal waters of the subtropical western Pacific using the hypervariable V4 region of the 18S rRNA gene. Picoeukaryote assemblages between two sites with different hydrography and trophic status were also compared. The approach gave a high coverage of the community at genetic difference ⩾5% but still underestimated the total diversity at a genetic difference ⩽2%. Diversity of picoeukaryotes was higher in an oligomesotrophic bay than in a eutrophic bay. Stramenopiles, dinoflagellates, ciliates and prasinophytes were the dominant groups comprising approximately 27, 19, 11 and 11%, respectively, of the picoeukaryotes. Water samples collected from the two bays contained different high-level taxonomic groups and phylotype operational taxonomic units of picoeukaryotes. Our study represents one of the first and most comprehensive examinations of marine picoeukaryotic diversity using the 454 sequencing-by-synthesis technology.
Bacterial diversity in the oral cavity of 10 healthy individuals
Authors: Bik Elisabeth M , Long Clara Davis , Armitage Gary C , Loomer Peter , Emerson Joanne , Mongodin Emmanuel F , Nelson Karen E , Gill Steven R , Fraser-Liggett Claire M , Relman David A
Published: March 2010

The composition of the oral microbiota from 10 individuals with healthy oral tissues was determined using culture-independent techniques. From each individual, 26 specimens, each from different oral sites at a single point in time, were collected and pooled. An 11th pool was constructed using portions of the subgingival specimens from all 10 individuals. The 16S ribosomal RNA gene was amplified using broad-range bacterial primers, and clone libraries from the individual and subgingival pools were constructed. From a total of 11 368 high-quality, nonchimeric, near full-length sequences, 247 species-level phylotypes (using a 99% sequence identity threshold) and 9 bacterial phyla were identified. At least 15 bacterial genera were conserved among all 10 individuals, with significant interindividual differences at the species and strain level. Comparisons of these oral bacterial sequences with near full-length sequences found previously in the large intestines and feces of other healthy individuals suggest that the mouth and intestinal tract harbor distinct sets of bacteria. Co-occurrence analysis showed significant segregation of taxa when community membership was examined at the level of genus, but not at the level of species, suggesting that ecologically significant, competitive interactions are more apparent at a broader taxonomic level than species. This study is one of the more comprehensive, high-resolution analyses of bacterial diversity within the healthy human mouth to date, and highlights the value of tools from macroecology for enhancing our understanding of bacterial ecology in human health.
The Influence of Higher Protein Intake and Greater Eating Frequency on Appetite Control in Overweight and Obese Men
Authors: Leidy Heather J. , Armstrong Cheryl L.H. , Tang Minghua , Mattes Richard D. , Campbell Wayne W.
Published: March 2010

The purpose of this study was to determine the effects of dietary protein intake and eating frequency on perceived appetite, satiety, and hormonal responses in overweight/obese men. Thirteen men (age 51 ± 4 years; BMI 31.3 ± 0.8 kg/m2) consumed eucaloric diets containing normal protein (79 ± 2 g protein/day; 14% of energy intake as protein) or higher protein (138 ± 3 g protein/day; 25% of energy intake as protein) equally divided among three eating occasions (3‐EO; every 4 h) or six eating occasions (6‐EO; every 2 h) on four separate days in randomized order. Hunger, fullness, plasma glucose, and hormonal responses were assessed throughout 11 h. No protein × eating frequency interactions were observed for any of the outcomes. Independent of eating frequency, higher protein led to greater daily fullness (P< 0.05) and peptide YY (PYY) concentrations (P< 0.05). In contrast, higher protein led to greater daily ghrelin concentrations (P< 0.05) vs. normal protein. Protein quantity did not influence daily hunger, glucose, or insulin concentrations. Independent of dietary protein, 6‐EO led to lower daily fullness (P< 0.05) and PYY concentrations (P< 0.05). The 6‐EO also led to lower glucose (P< 0.05) and insulin concentrations (P< 0.05) vs. 3‐EO. Although the hunger‐related perceived sensations and hormonal responses were conflicting, the fullness‐related responses were consistently greater with higher protein intake but lower with increased eating frequency. Collectively, these data suggest that higher protein intake promotes satiety and challenge the concept that increasing the number of eating occasions enhances satiety in overweight and obese men.
The Relationship of Weight‐Related Attitudes With Suicidal Behaviors in Korean Adolescents
Authors: Kim Jun‐Su , Lee Kayoung
Published: March 2010

The objective of this study was to assess the relationship between weight‐related attitudes and suicidal behavior after consideration of depressive mood in Korean adolescents. The study population consisted of a nationally representative sample of 74,698 adolescents (n = 39,466 boys, 35,232 girls) in middle and high school who completed the Korea Youth Risk Behavior Web‐based Survey (KYRBWS) in 2007. Logistic regression models were used to examine the relationships between measures of weight‐related and self‐reported suicidal behavior, controlling for demographics, depressive mood, stress perception, level of school achievement, and substance use. Suicide attempts were surveyed among those reported to have suicidal ideation (n = 7,579 boys, 10,204 girls). Significantly more girls than boys reported suicidal ideation (29 vs. 19%) and suicide attempts (7.7 vs. 4.5%). Factors significantly associated with suicidal ideation were overestimation of weight (vs. correct estimation) and behaviors to lose or gain weight (vs. no weight control) among boys and overestimation of weight and attempting to lose weight among girls. In contrast, the odds of suicide attempts were significantly higher among boys who tried to lose, gain, or maintain their weight (vs. no weight control) and girls who underestimated their weight (vs. correct estimation) and tried to lose weight (vs. no weight control). Boys and girls classified as overweight or at risk for overweight were significantly less likely to report suicide attempts compared to those classified as underweight. Weight‐related attitudes, such as incorrect weight perception and weight control behaviors, seem to be useful indicators for identifying Korean adolescents who are at risk for suicidal behaviors.
Relationships between plasma membrane microdomains and HIV‐1 assembly
Authors: Ono Akira
Published: March 2010

Advances in cell biology and biophysics revealed that cellular membranes consist of multiple microdomains with specific sets of components such as lipid rafts and TEMs (tetraspanin‐enriched microdomains). An increasing number of enveloped viruses have been shown to utilize these microdomains during their assembly. Among them, association of HIV‐1 (HIV type 1) and other retroviruses with lipid rafts and TEMs within the PM (plasma membrane) is well documented. In this review, I describe our current knowledge on interrelationships between PM microdomain organization and the HIV‐1 particle assembly process. Microdomain association during virus particle assembly may also modulate subsequent virus spread. Potential roles played by microdomains will be discussed with regard to two post‐assembly events, i.e., inhibition of virus release by a raft‐associated protein BST‐2/tetherin and cell‐to‐cell HIV‐1 transmission at virological synapses.
Activation of human pro-urokinase by unrelated proteases secreted by Pseudomonas aeruginosa
Authors: Beaufort Nathalie , Seweryn Paulina , de Bentzmann Sophie , Tang Aihua , Kellermann Josef , Grebenchtchikov Nicolai , Schmitt Manfred , Sommerhoff Christian P. , Pidard Dominique , Magdolen Viktor
Published: March 2010

Pathogenic bacteria, including Pseudomonas aeruginosa, interact with and engage the host plasminogen (Plg) activation system, which encompasses the urokinase (uPA)-type Plg activator, and is involved in extracellular proteolysis, including matrilysis and fibrinolysis. We hypothesized that secreted bacterial proteases might contribute to the activation of this major extracellular proteolytic system, thereby participating in bacterial dissemination. We report that LasB, a thermolysin-like metalloprotease secreted by Ps. aeruginosa, converts the human uPA zymogen into its active form (kcat=4.9 s−1, Km=8.9 μM). Accordingly, whereas the extracellular secretome from the LasB-expressing pseudomonal strain PAO1 efficiently activates pro-uPA, the secretome from the isogenic LasB-deficient strain PDO240 is markedly less potent in pro-uPA activation. Still, both secretomes induce some metalloprotease-independent activation of the human zymogen. The latter involves a serine protease, which we identified via both recombinant protein expression in Escherichia coli and purification from pseudomonal cultures as protease IV (PIV; kcat=0.73 s−1, Km=6.2 μM). In contrast, neither secretomes nor the pure proteases activate Plg. Along with this, LasB converts Plg into mini-Plg and angiostatin, whereas, as reported previously, it processes the uPA receptor, inactivates the plasminogen activator inhibitor 1, and activates pro-matrix metalloproteinase 2. PIV does not target these factors at all. To conclude, LasB and PIV, although belonging to different protease families and displaying quite different substrate specificities, both activate the urokinase-type precursor of the Plg activation cascade. Direct pro-uPA activation, as also reported for other bacterial proteases, might be a frequent phenomenon that contributes to bacterial virulence.
SENP1 participates in the dynamic regulation of Elk-1 SUMOylation
Authors: Witty James , Aguilar-Martinez Elisa , Sharrocks Andrew D.
Published: March 2010

The modification of proteins with SUMO (small ubiquitin-related modifier) plays an important role in determining their functional properties. Importantly though, SUMOylation is a highly dynamic process enabling transient responses to be elicited. This dynamism is controlled by two competing conjugating and deconjugating activities. The latter activity is mediated by the SENP [SUMO1/sentrin/SMT3 (suppressor of mif two 3 homologue 1)-specific peptidase] family of SUMO-specific proteases. The transcription factor Elk-1 [ETS (E twenty-six)-like 1] undergoes rapid de-SUMOylation following cellular stimulation with growth factors, and this contributes to its conversion from a SUMO-dependent repressor into a potent transcriptional activator. In the present study we demonstrate an important role for SENP1 in the de-SUMOylation of Elk-1, and therefore an integral role in determining the Elk-1-dependent transcriptional programme. Among the SENPs, Elk-1 preferentially forms a complex with SENP1. This preferential binding is reflected by the higher efficiency of SENP1 in promoting Elk-1 transactivation. Moreover, depletion of SENP1 causes a reciprocal effect and reduces the transactivation properties of Elk-1. Partial redundancy of function with SENP2 is revealed by combinatorial knockdown studies. Importantly, depletion of SENP1 also reduces the activation of the Elk-1 target gene c-FOS. Taken together, these results therefore reveal an important role for SENP1 in the regulation of Elk-1-mediated gene expression in response to mitogenic signalling cues.
O-Acetylation of sialic acid on Group BStreptococcusinhibits neutrophil suppression and virulence
Authors: Weiman Shannon , Uchiyama Satoshi , Lin Feng-Ying C. , Chaffin Donald , Varki Ajit , Nizet Victor , Lewis Amanda L.
Published: March 2010

GBS (Group B Streptococcus) requires capsular Sia (sialic acid) for virulence and partially modifies this sugar by O-acetylation. In the present paper we describe serotype-specific patterns of GBS Sia O-acetylation that can be manipulated by genetic and biochemical means. In vitro and in vivo assays demonstrate that this subtle modification attenuates GBS Sia-mediated neutrophil suppression and animal virulence.
Beam dynamics of the Neutralized Drift Compression Experiment-II, a novel pulse-compressing ion accelerator
Authors: Friedman A. , Barnard J. J. , Cohen R. H. , Grote D. P. , Lund S. M. , Sharp W. M. , Faltens A. , Henestroza E. , Jung J.-Y. , Kwan J. W. , Lee E. P. , Leitner M. A. , Logan B. G. , Vay J.-L. , Waldron W. L. , Davidson R. C. , Dorf M. , Gilson E. P. , Kaganovich I. D.
Published: March 2010

Intense beams of heavy ions are well suited for heating matter to regimes of emerging interest. A new facility, NDCX-II, will enable studies of warm dense matter at ∼1 eV and near-solid density, and of heavy-ion inertial fusion target physics relevant to electric power production. For these applications the beam must deposit its energy rapidly, before the target can expand significantly. To form such pulses, ion beams are temporally compressed in neutralizing plasma; current amplification factors of ∼50–100 are routinely obtained on the Neutralized Drift Compression Experiment (NDCX) at the Lawrence Berkeley National Laboratory. In the NDCX-II physics design, an initial non-neutralized compression renders the pulse short enough that existing high-voltage pulsed power can be employed. This compression is first halted and then reversed by the beam’s longitudinal space-charge field. Downstream induction cells provide acceleration and impose the head-to-tail velocity gradient that leads to the final neutralized compression onto the target. This paper describes the discrete-particle simulation models (one-, two-, and three-dimensional) employed and the space-charge-dominated beam dynamics being realized.
Involutivity of field equations
Authors: Kruglikov Boris
Published: March 2010

We prove involutivity of Einstein, Einstein–Maxwell, and other field equations by calculating the Spencer cohomology of these systems. The relation with Cartan method is traced in detail. Basic implications through Cartan–Kähler theory are derived.
Homogeneous dislocation nucleation in cyclotrimethylene trinitramine under shock loading
Authors: Cawkwell M. J. , Ramos K. J. , Hooks D. E. , Sewell Thomas D.
Published: March 2010

The propagation of shock waves normal to (111) in the energetic molecular crystal cyclotrimethylene trinitramine (RDX) has been studied using large-scale molecular dynamics simulations. Partial dislocation loops with Burgers vector 0.16[010] are nucleated homogeneously on (001) at Rankine–Hugoniot shock pressures greater than 1.3 GPa. Calculations of the [010] cross-section of the (001) generalized stacking fault energy surface as a function of applied pressure along [001] reveals that the stacking fault enclosed by the partial dislocation loops is rendered metastable by a stress-induced change in molecular conformation. Furthermore, large-scale molecular dynamics simulations performed on quasi-two-dimensional (111)-oriented single crystals show a two-wave elastic-plastic response with a “galloping” plastic wave. We propose that the onset of homogeneous dislocation nucleation accounts for the abrupt change in the elastic-plastic response of macroscopic (111)-oriented RDX single crystals observed in recent experiments by giving rise to an anomalous plastic hardening.
Si–Ge interdiffusion under oxidizing conditions in epitaxial SiGe heterostructures with high compressive stress
Authors: Xia Guangrui , Hoyt Judy L.
Published: March 2010

Si–Ge interdiffusion under oxidizing and inert conditions has been studied in epitaxial relaxed Si1−xGex/compressive Si1−yGey/relaxed Si1−xGex heterostructures. The interdiffusion was measured by secondary ion mass spectroscopy (SIMS) and studied using simulations. Within the SIMS accuracy, the measured Ge profiles show that oxidation has a small effect, if any, on the Si–Ge interdiffusion of these structures. These results suggest that oxidation does not accelerate Si–Ge interdiffusion significantly, which lessens process integration constraints for SiGe devices such as high mobility dual channel metal oxide semiconductor field effect transistors and heterostructure tunneling field effect transistors.
High frequency impedance spectroscopy on ZnO nanorod arrays
Authors: Scrymgeour David A. , Highstrete Clark , Lee Yun-Ju , Hsu Julia W.-P. , Lee Mark
Published: March 2010

The radio-frequency (rf)-to-microwave impedance spectra of solution grown ZnO nanorods have been measured from 0.1 to 50 GHz using vector network analysis. To increase interaction with rf/microwave fields, the nanorods were assembled by dielectrophoresis into arrays on coplanar waveguides. The average complex impedance frequency response per nanorod in an array was accurately modeled as a simple three-element circuit composed of the inherent nanorod resistance in series with a parallel resistor-capacitor representing the contact. The nanorod resistance dominates at high frequencies while the contact impedance dominates at low frequencies, permitting a quantitative separation of contact effects from nanorod properties. The average inherent resistivity of a nanorod was found to be ∼10−2 Ω cm, indicating the nanorods were unintentionally highly doped. Accuracy of the inherent resistance measurement was limited by the highly conductive nature of the nanorods used and the upper limit of the experimental frequency range. Determination of the nanorod resistance becomes more accurate for higher resistivity nanorods, so high frequency impedance spectroscopy will provide an increasingly valuable electrical characterization technique as the ability to synthesize more intrinsic (i.e., lower unintentional dopant density) ZnO nanorods improves.
Influence of an imposed flow on the stability of a gravity current in a near horizontal duct
Authors: Taghavi S. M. , Séon T. , Martinez D. M. , Frigaard I. A.
Published: March 2010

We study experimentally the effect of a mean flow imposed on a buoyant exchange flow of two miscible fluids of equal viscosity in a long tube oriented close to horizontal. We measure the evolution of the front velocity Vf as a function of the imposed velocity V0. At low V0, an exchange-flow dominated regime is found, as expected, and is characterized here by Kelvin–Helmholtz-like instabilities. With increasing V0 we observed that the flow becomes stable. Here also Vf increases linearly with V0 with slope of >1. At large V0 we find Vf∼V0.
In situ laser-based resonant ultrasound measurements of microstructure mediated mechanical property evolution
Authors: Hurley D. H. , Reese S. J. , Park S. K. , Utegulov Z. , Kennedy J. R. , Telschow K. L.
Published: March 2010

In situ laser-based resonant ultrasound spectroscopy is used to characterize the development of a recrystallized microstructure in a high purity copper sample. The modal shapes, used for mode identification, of several resonant modes are determined before and after annealing by raster scanning the laser interferometric probe. This information is used to isolate the motion of individual modes during high temperature annealing. The evolution of a particular mode during annealing is examined in detail. During recrystallization, the center frequency of this mode shifts by approximately 20% of the original value. Using electron backscatter data it is shown that the majority of this shift is due to changes in the polycrystal average elastic stiffness tensor, driven by changes in texture, and that changes in dislocation density and pinning length are secondary influences.
Luminescent core-shell nanostructures of silicon and silicon oxide: Nanodots and nanorods
Authors: Ray Mallar , Basu Tuhin Shuvra , Jana Arpita , Bandyopadhyay Nil Ratan , Hossain Syed Minhaz , Pramanick Ashit Kumar , Klie Robert F.
Published: March 2010

We report synthesis and luminescent characteristics of core-shell nanostructures of silicon and silicon oxide having two different morphologies—spherical (nanodot) and rodlike (nanorod), prepared by controlled oxidation of mechanically milled crystalline silicon and by exfoliation of the affected layer of porous silicon. Colloidal suspensions of these nanostructures exhibit intense room temperature photoluminescence (PL), detectable with the unaided eye. PL band peak energies of the colloidal suspensions formed from porous silicon are blue shifted by ∼1 eV compared to the as-prepared films on silicon substrate. In addition, PL spectra of all the colloidal suspensions blueshift with increase in excitation energy but the PL peaks of as-prepared porous silicon are independent of excitation. However, shape of the nanocrystals (spherical or rodlike) is found to have little effect on the emission spectra. These observations are explained in terms discretization of phonon density of states and electronic transitions involving surface defect states and quantum confinement induced widened band states.
Colloidal gold nanosphere dispersions in smectic liquid crystals and thin nanoparticle-decorated smectic films
Authors: Pratibha R. , Park W. , Smalyukh I. I.
Published: March 2010

We demonstrate that the layer structure and elasticity stabilize dispersions of colloidal nanoparticles in smectic liquid crystals. We use surface plasmon resonance spectra of gold nanospheres to probe their spatial distributions in the bulk of smectic lamellae. The average interparticle distances between the well-separated nanoinclusions in thin (<100 nm) smectic films are probed by atomic force microscopy. We show that limited motion of nanoparticles across layers due to the one-dimensional quasi-long-range solid-like structure and their elasticity-mediated interactions preclude irreversible aggregation and enhance the stability of the ensuing nanoscale dispersions in thermotropic smectic liquid crystals.
A superconducting transformer system for high current cable testing
Authors: Godeke A. , Dietderich D. R. , Joseph J. M. , Lizarazo J. , Prestemon S. O. , Miller G. , Weijers H. W.
Published: March 2010

This article describes the development of a direct-current (dc) superconducting transformer system for the high current test of superconducting cables. The transformer consists of a core-free 10 464 turn primary solenoid which is enclosed by a 6.5 turn secondary. The transformer is designed to deliver a 50 kA dc secondary current at a dc primary current of about 50 A. The secondary current is measured inductively using two toroidal-wound Rogowski coils. The Rogowski coil signal is digitally integrated, resulting in a voltage signal that is proportional to the secondary current. This voltage signal is used to control the secondary current using a feedback loop which automatically compensates for resistive losses in the splices to the superconducting cable samples that are connected to the secondary. The system has been commissioned up to 28 kA secondary current. The reproducibility in the secondary current measurement is better than 0.05% for the relevant current range up to 25 kA. The drift in the secondary current, which results from drift in the digital integrator, is estimated to be below 0.5 A/min. The system’s performance is further demonstrated through a voltage-current measurement on a superconducting cable sample at 11 T background magnetic field. The superconducting transformer system enables fast, high resolution, economic, and safe tests of the critical current of superconducting cable samples.
Design of a digital multiradian phase detector and its application in fusion plasma interferometry
Authors: Mlynek A. , Schramm G. , Eixenberger H. , Sips G. , McCormick K. , Zilker M. , Behler K. , Eheberg J. ,   ASDEX Upgrade Team
Published: March 2010

We discuss the circuit design of a digital multiradian phase detector that measures the phase difference between two 10 kHz square wave TTL signals and provides the result as a binary number. The phase resolution of the circuit is 1/64 period and its dynamic range is 256 periods. This circuit has been developed for fusion plasma interferometry with submillimeter waves on the ASDEX Upgrade tokamak. The results from interferometric density measurement are discussed and compared to those obtained with the previously used phase detectors, especially with respect to the occurrence of phase jumps. It is illustrated that the new phase measurement provides a powerful tool for automatic real-time validation of the measured density, which is important for feedback algorithms that are sensitive to spurious density signals.
Rotating helical turbulence. I. Global evolution and spectral behavior
Authors: Mininni P. D. , Pouquet A.
Published: March 2010

We present results from two 15363 direct numerical simulations of rotating turbulence where both energy and helicity are injected into the flow by an external forcing. The dual cascade of energy and helicity toward smaller scales observed in isotropic and homogeneous turbulence is broken in the presence of rotation, with the development of an inverse cascade of energy now coexisting with direct cascades of energy and helicity. In the direct cascade range, the flux of helicity dominates over that of energy at low Rossby number. These cascades have several consequences for the statistics of the flow. The evolution of global quantities and of the energy and helicity spectra is studied, and comparisons with simulations at different Reynolds and Rossby numbers at lower resolution are done to identify scaling laws.
Rotating helical turbulence. II. Intermittency, scale invariance, and structures
Authors: Mininni P. D. , Pouquet A.
Published: March 2010

We study the intermittency properties of the energy and helicity cascades in two 15363 direct numerical simulations of helical rotating turbulence. Symmetric and antisymmetric velocity increments are examined, as well as probability density functions of the velocity field and of the helicity density. It is found that the direct cascade of energy to small scales is scale invariant and nonintermittent, whereas the direct cascade of helicity is highly intermittent. Furthermore, the study of structure functions of different orders allows us to identify a recovery of isotropy of strong events at very small scales in the flow. Finally, we observe the juxtaposition in space of strong laminar and persistent helical columns next to time-varying vortex tangles, the former being associated with the self-similarity of energy and the latter with the intermittency of helicity.