bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of feeding Mediterranean food industry by-products and forages to Awassi sheep on physicochemical properties of milk, yoghurt and cheese
Authors: Abbeddou Souheila , Rischkowsky Barbara , Hilali Muhi El-Dine , Hess Hans Dieter , Kreuzer Michael
Published: October 2011

Feeding agro-industrial by-products and unconventional forages, rich in potentially anti-nutritional factors, may influence the quality of the raw milk and the dairy products prepared therefrom. The aim of the present study was to determine side-effects on physicochemical properties of milk, yoghurt and cheese of feeding diets where one third were feeds either rich in lipids (tomato pomace and olive cake) or phenols (olive leaves and lentil straw) or electrolytes (Atriplex leaves). The diets, including a control diet, were designed to be isoenergetic and isonitrogenous. They were fed in amounts of 2 5 kg dry matter/day per head during 50 days to 6×10 multiparous fat-tailed Awassi ewes. Milk samples were analysed for various physicochemical traits and fatty acid composition on days 0, 24, 36 and 48. Three times, milk pooled by group was processed to yoghurt and non-aged farmer-type cheese, which were analysed for their gross and fatty acid composition and texture, and were subjected to sensory evaluation. Feeding olive cake and tomato pomace reduced milk casein, but increased proportions of monounsaturated fatty acids. There were some variations in minerals among test diets but, contrary to expectations, Atriplex did not increase milk sodium. The nutritional composition of yoghurt and cheese was not varied much by the test feeds, except for some changes in fatty acid profile similar to the milk. Yoghurt firmness declined with all test diets, but texture score tended to be lower only for olive cake and leaf diets relative to control. Cheese firmness was increased by feeding the Atriplex leaf and olive cake diets which was also reflected in the texture scores. No off-flavours were reported. Possible reasons for effects on the dairy products are discussed. In conclusion, the feeds investigated had certain effects on the physicochemical properties of dairy products, but these were neither very systematic nor large thus not prohibiting their use in Mediterranean sheep milk production systems.
Biased sex ratio and niche restriction in Baruscapillaria obsignata (Madsen 1945) (Nematoda, Capillariidae) from Columba livia (Aves, Columbidae)
Authors: D'Ávila S. , Bessa E.C.A. , Souza-Lima S. , Rodrigues M.L.A.
Published: October 2011

In the present study populations of the avian nematode species Baruscapillaria obsignata are described from Columba livia. Male and female individuals were obtained from 27 birds, fixed in alcohol/formalin/acetic acid (AFA) and preserved in 70% ethanol. Nematodes were identified and then counted under a stereoscopic microscope. Baruscapillaria obsignata were much more frequent in the anterior third of the small intestine, and females were more abundant than males in all infra populations. The prevalence was 55.6%, mean intensity was 11.8 (median 11.0; range 1–31) and abundance 6.56. In the present study, we observed an aggregated distribution of parasite infrapopulations, as demonstrated by the value of the exponent of the negative binomial distribution, K = 0.2773; by the discrepancy index, D = 0.656 and by the variance/mean ratio, 12.44. The female/male sex ratios found in all infrapopulations were always greater than 1, showing a bias in favour of female abundance. This tendency was especially marked in infrapopulations containing fewer individuals. The sizes of infrapopulations ranged from 5 to 31 individuals. The mean sex ratio observed was 2.69 ± 3.28 (median 1.83; range 0–11). In infrapopulations with 5–15 individuals, the sex ratios observed varied from 2.6 to 11, while in those with 17–31 individuals, the sex ratios were lower, ranging from 1.7 to 2.4. There was a negative correlation between the intensity of infection and the sex ratio of infrapopulations. Results are discussed in terms of possible factors influencing the processes that lead to niche restriction and biased sex ratios in parasite infrapopulations.
Implicit and explicit knowledge in second language acquisition
Authors: REBUSCHAT PATRICK , WILLIAMS JOHN N.
Published: October 2011

Language development is frequently characterized as a process where learning proceeds implicitly, that is, incidentally and in absence of awareness of what was learned. This article reports the results of two experiments that investigated whether second language acquisition can also result in implicit knowledge. Adult learners were trained on an artificial language under incidental learning conditions and then tested by means of grammaticality judgments and subjective measures of awareness. The results indicate that incidental exposure to second language syntax can result in unconscious knowledge, which suggests that at least some of the learning in this experiment was implicit. At the same time, however, it was also found that conscious (but unverbalizable) knowledge was clearly linked to improved performance in the grammaticality judgment task.
A NEW NAME FOR A SOUTH ASIAN XYLOPIA (ANNONACEAE) SPECIES
Authors: Turner I. M.
Published: October 2011

Xylopia parvifolia (Wight) Hook.f. & Thomson (Annonaceae), based on Patonia parvifolia Wight, is a tree species native to Sri Lanka and India. Unfortunately the widely used name is an illegitimate later homonym. Xylopia patoniae I.M.Turner is here proposed as an avowed substitute. There have been two proposals to lectotypify Patonia Wight. The earliest, and one to be followed, proposed Patonia parvifolia Wight as the lectotype, maintaining Patonia as a synonym of Xylopia. A later proposal to make Patonia walkeri Wight (≡ Diospyros walkeri (Wight) Gürke) the type has to be disregarded.
From market to state: wealth transfers in the Portuguese nationalisations of the 1970s
Authors: Alpalhão Rui
Published: October 2011

In the second half of the 1970s, following the so-called ‘Carnation Revolution’ and when a global wave of privatisations started, the Portuguese government nationalised most of the companies listed on the Lisbon Exchange. A few years later the shareholders of nationalised companies were paid indemnities. The nationalisations radically changed the Portuguese corporate scene and led to very important wealth transfers. Contrary to what is usually assumed, we conclude that this transfer was detrimental to holders of large shareholdings, but favourable to small shareholders and, on average, akin to fair compensation based on market exchange.
Understanding the Rise of Talk Radio
Authors: Berry Jeffrey M. , Sobieraj Sarah
Published: October 2011

The number of radio stations airing political talk shows—predominantly conservative talk radio—has surged in the past few years. This massive change in the radio industry says something about the demand for such shows, but attributing the rise of talk radio to a corresponding rise in conservative popular opinion is misleading. We argue that this remarkable growth is better explained by the collision of two changes that have transformed the radio business: deregulation and the mainstreaming of digital music technologies. Regulatory changes have shifted much of radio production and control from local to mass production (managed by industry giants such as Clear Channel Communications) and created a context ripe for nationally syndicated hosts such as Rush Limbaugh, Glenn Beck, and Mark Levin. Meanwhile, rapid technological changes have given consumers more control over the way they listen to music. Technologies such as MP3 players, Internet radio, smart phones, and Pandora Radio have made it more difficult for stations with a music format to be profitable. As music programming has become more problematic, many stations have developed a highly successful business model by converting to talk formats airing nationally syndicated shows.
Race and Religion in the Political Problematization of the American Muslim
Authors: Akhtar Iqbal
Published: October 2011

This article examines how the American civil response to September 11 profoundly transformed the core of American Muslim political identity for a generation. I outline the evolving contours of the American Muslim as citizens after September 11 through an analysis of the impact of race and religion on two relationships: state to citizen and citizen to citizen. The American political response to September 11 had both positive and negative impacts for domiciled Muslims. At the national level, this event has forced American Muslims into a period of institution building and active citizenship while the federal government's response has problematized the Muslim as a continuous potential security threat. One simmering question for the American citizenry in general concerns the loyalty of the American Muslim. In the future, the American Muslim political class will be engaged in a continued effort to write Muslims into the American narrative in the same way that previous immigrant groups have fought to reappropriate “Americanness.” The larger philosophical question in this process is how, in doing so, this group can prove its loyalty to the nation while maintaining a distinctive religious culture and heritage. What will be the future core of the maturing American Muslim as both a citizen of the republic and a servant of his or her god?
The Cultural Orientation of Mass Political Opinion
Authors: Gastil John , Braman Don , Kahan Dan , Slovic Paul
Published: October 2011

Most Americans lack any substantial degree of ideological sophistication (Kinder 1998), yet they often manage to express coherent views across a range of issues. The conventional explanation for this is that people rely on judgmental shortcuts (e.g., Sniderman, Brody, and Tetlock 1991). These “heuristics” permit individuals with sufficient political sophistication to sort and filter incoming messages to form relatively consistent views that align with preexisting values (Zaller 1992).
How Cultural Orientations Create Shifting National Security Coalitions on Nuclear Weapons and Terrorist Threats in the American Public
Authors: Ripberger Joseph T. , Jenkins-Smith Hank C. , Herron Kerry G.
Published: October 2011

Scholars have used cultural theory (CT) to explain risk perceptions and opinion formation across an impressive array of public issues, ranging from environmental, regulatory, and energy policy to public health and economics. Although disparate, all these issues concern domestic policies. This article breaks with this trend by exploring the extent to which CT can help scholars better understand public beliefs about national security. Of critical importance in debates about national security are perceptions of individual versus collective threat and the appropriate role of authoritative institutions in protecting society from these threats. Because CT provides a framework that explicitly addresses these dimensions, national security issues provide an illuminating canvas for evaluating the theory's explanatory utility.
Teaching Students about Congress and Civic Engagement
Authors: Hall B. Welling
Published: October 2011

As a tenured, full professor in an endowed peace studies chair at my home institution, I chose to spend my 2009–10 sabbatical year as an American Political Science Association Congressional Fellow. Why? As I saw it, my colleagues who teach chemistry need to work with electron spectrometers; my colleagues who teach ethnomusicology need to perform with Javanese gamelans. In an analogous way, I believed that my own work with Congress would energize and refocus my research and teaching. All subfields of intellectual inquiry have their blind spots, and within the subfield of peace studies the largest blind spot may be the perspective that I thought might be gained from being a foreign policy insider. Again and again, my courses began and ended with students asking me to explain how or why the United States behaved and behaves in ways that baffle the rest of the world. I found myself saying something about “political will” and believed that if I were to answer that question in a way that felt remotely satisfying, I needed to spend some time on the ground observing how the “sausage” was made.
Beverage consumption and BMI of British schoolchildren aged 9–13 years
Authors: Coppinger Tara , Jeanes YM , Mitchell M , Reeves S
Published: October 2011

Objective

Adequate fluid intake has been well documented as important for health but whether it has adverse effects on overall energy and sugar intakes remains under debate. Many dietary studies continue to refrain from reporting on beverage consumption, which the present study aimed to address.

Design

A cross-sectional survey investigated self-reported measures of dietary intake and anthropometric measurements.

Setting

Primary and secondary schools in south-west London, UK.

Subjects

Boys and girls (n 248) aged 9–13 years.

Results

Boys consumed 10 % and girls consumed 9 % of their daily energy intake from beverages and most children had total sugar intakes greater than recommended. Beverages contributed between a quarter and a third of all sugars consumed, with boys aged 11–13 years consuming 32 % of their total sugar from beverages. There was a strong relationship between consumption of beverages and energy intake; however, there was no relationship between beverage type and either BMI or BMI Z-score. Fruit juices and smoothies were consumed most frequently by all girls and 9–10-year-old boys; boys aged 11–13 years preferred soft drinks and consumed more of their daily energy from soft drinks. Milk and plain water as beverages were less popular.

Conclusions

Although current health promotion campaigns in schools merit the attention being given to improving hydration and reducing soft drinks consumption, it may be also important to educate children on the energy and sugar contents of all beverages. These include soft drinks, as well as fruit juices and smoothies, which are both popular and consumed regularly.
Global prediction of the vertical total electron content of the ionosphere based on GPS data
Authors: García‐Rigo A. , Monte E. , Hernández‐Pajares M. , Juan J. M. , Sanz J. , Aragón‐Angel A. , Salazar D.
Published: October 2011

Although vertical total electron content (VTEC) forecasting is still an open subject of research, the use of predictions of the ionospheric state at a scale of several days is an area of increased interest. A global VTEC forecast product for two days ahead, which is based exclusively on actual Global Positioning System (GPS) data, has been developed in the frame of the International Global Navigation Satellite Systems (GNSS) Service (IGS) Ionospheric Working Group (IGS Iono‐WG). The UPC ionospheric VTEC prediction model is based on the Discrete Cosine Transform (DCT), which is widely used in image compression (for instance, in JPEG format). Additionally, a linear regression module is used to forecast the time evolution of each of the DCT coefficients. The use of the DCT coefficients is justified because they represent global features of the whole two‐dimensional VTEC map/image. Also, one can therefore introduce prior information affecting the VTEC, for instance, smoothness or the distribution of relevant features in different directions. For this purpose, the use of a long time series of final/rapid UPC VTEC maps is required. Currently, the UPC Predicted product is being automatically generated in test mode and is made available through the main IGS server for public access. This product is also used to generate two days ahead preliminary combined IGS Predicted product. Finally, the results presented in this work suggest that the two days ahead UPC Predicted product could become an official IGS product in the near future.
Acquisition of epibiotic bacteria along the life cycle of the hydrothermal shrimp Rimicaris exoculata
Authors: Guri Mathieu , Durand Lucile , Cueff-Gauchard Valérie , Zbinden Magali , Crassous Philippe , Shillito Bruce , Cambon-Bonavita Marie-Anne
Published: October 2011

The caridean shrimp Rimicaris exoculata dominates the fauna at several Mid-Atlantic Ridge hydrothermal vent sites. This shrimp has an enlarged gill chamber, harboring a dense ectosymbiotic community of chemoautotrophic bacteria associated with mineral oxide deposits. Until now, their acquisition is not fully understood. At three hydrothermal vent sites, we analyzed the epibionts diversity at different moult stages and also in the first stages of the shrimp life (eggs, hatched eggs (with larvae) and juveniles). Hatched eggs associated with young larvae were collected for the first time directly from gravid females at the Logachev vent site during the Serpentine cruise. An approach using 16S rRNA clone libraries, scanning and transmission electron microscopy, and fluorescent in situ hybridization was used. Molecular results and microscope observations indicated a switch in the composition of the bacterial community between early R. exoculata life cycle stage (egg libraries dominated by the Gammaproteobacteria) and later stages (juvenile/adult libraries dominated by the Epsilonproteobacteria). We hypothesized that the epibiotic phylotype composition could vary according to the life stage of the shrimp. Our results confirmed the occurrence of a symbiosis with Gammaproteobacteria and Epsilonproteobacteria, but more complex than previously assumed. We revealed the presence of active type-I methanotrophic bacteria colonizing the cephalothorax of shrimps from the Rainbow site. They were also present on the eggs from the Logachev site. This could be the first ‘epibiotic’ association between methanotrophic bacteria and hydrothermal vent crustacean. We discuss possible transmission pathways for epibionts linked to the shrimp life cycle.
Microbiota in the Oral Subgingival Biofilm Is Associated With Obesity in Adolescence
Authors: Zeigler Cecilia C. , Persson G. Rutger , Wondimu Biniyam , Marcus Claude , Sobko Tanja , Modéer Thomas
Published: October 2011

To test the hypothesis whether microbiota in oral biofilm is linked with obesity in adolescents we designed this cross‐sectional study. Obese adolescents (n = 29) with a mean age of 14.7 years and normal weight subjects (n = 58) matched by age and gender were examined with respect to visible plaque index (VPI%) and gingival inflammation (bleeding on probing (BOP%)). Stimulated saliva was collected. They answered a questionnaire concerning medical history, medication, oral hygiene habits, smoking habits, and sociodemographic background. Microbiological samples taken from the gingival crevice was analyzed by checkerboard DNA‐DNA hybridization technique. The sum of bacterial cells in subgingival biofilm was significantly associated with obesity (P < 0.001). The link between sum of bacterial cells and obesity was not confounded by any of the studied variables (chronic disease, medication, VPI%, BOP%, flow rate of whole saliva, or meal frequency). Totally 23 bacterial species were present in approximately threefold higher amounts, on average, in obese subjects compared with normal weight controls. Of the Proteobacteria phylum, Campylobacter rectus and Neisseria mucosa were present in sixfold higher amounts among obese subjects. The association between obesity and sum of bacterial cells in oral subgingival biofilm indicates a possible link between oral microbiota and obesity in adolescents.
Short‐Term Psychological Outcomes in Severely Obese Adolescents After Bariatric Surgery
Authors: Järvholm Kajsa , Olbers Torsten , Marcus Claude , Mårild Staffan , Gronowitz Eva , Friberg Peter , Johnsson Per , Flodmark Carl‐Erik
Published: October 2011

Bariatric surgery is suggested as a treatment option for severely obese adolescents. Because adolescence is characterized by intense psychosocial adjustment and development, it is important to study the effect of this procedure on adolescents' psychological health. This study examined baseline status and short‐term changes in anxiety, depression, anger, disruptive behavior, and self‐concept in 37 adolescents (mean age 16.6 ± 1.3). Participants completed the Beck Youth Inventories (BYI) at inclusion and (on average) 4 months after undergoing Roux‐en‐Y gastric bypass (RYGB). Internalizing (anxiety and depression) and externalizing (anger and disruptive behavior) symptoms were higher at baseline than gender‐specific norms. One fifth had a very low self‐concept. Four months after surgery, the adolescents showed significantly fewer symptoms of anxiety and depression and significantly improved self‐concept from baseline. Anger and disruptive behavior showed no significant changes. An analysis of clinically meaningful changes was conducted, and besides the overall positive outcome, 16% (n = 6) of the adolescents had deteriorated on two or more inventories in BYI shortly after surgery. This impaired group did not show any specific features at inclusion. The results indicate the importance of psychological monitoring immediately after bariatric surgery and the need for additional psychosocial support to be available for vulnerable sub‐groups of adolescents. Further studies with larger samples are necessary to identify characteristics predictive of short‐term adverse psychological outcomes in adolescents after bariatric surgery.
Body Size Matters in Provision of Help: Factors Related to Children's Willingness to Help Overweight Peers
Authors: Patel Sanobar L. , Holub Shayla C.
Published: October 2011

Although children who are overweight may be vulnerable to negative social experiences, little is known about whether children will offer help to peers who are overweight. The present study examined whether children would offer aid to peers who are overweight with everyday tasks (such as picking up toys). This study also examined whether weight stereotypes and intentions to befriend these peers are related to intentions to help. Fifty‐one children, aged 4–8, were interviewed about their stereotypes and behavioral intentions. Findings revealed that children were less likely to help overweight than average weight peers. Children who did not hold positive stereotypes about thinness and those who chose to play with overweight peers were more likely to help peers who are overweight. Results suggest that weight prejudice is pervasive and that children who are overweight might not be offered aid in classroom settings, highlighting the need for early intervention.
Adiponectin‐Deficiency Exaggerates Sepsis‐Induced Microvascular Dysfunction in the Mouse Brain
Authors: Vachharajani Vidula , Cunningham Christie , Yoza Barbara , Carson John , Vachharajani Tushar J. , McCall Charles
Published: October 2011

Obesity increases circulating cell‐endothelial cell interactions; an early marker of inflammation in laboratory model of sepsis, but little is known about the effect of different adipokines. Adiponectin is an anti‐inflammatory adipokine secreted by adipocytes. Adiponectin deficiency is implicated in exaggerated proinflammatory phenotype in both obesity and sepsis via increased proinflammatory cytokine expression. However the effect of adiponectin deficiency on circulating cell‐endothelial cell interactions in polymicrobial sepsis is unknown. Furthermore although brain dysfunction in septic patients is a known predictor of death, the pathophysiology involved is unknown. In the current study, we examined the effects of adiponectin deficiency on leukocyte (LA) and platelet adhesion (PA) in cerebral microcirculation of septic mice. Adiponectin deficient (Adipoq−/−: Adko) and background strain C57Bl/6 (wild type (WT)) mice were used. Sepsis was induced using cecal ligation and puncture (CLP). We studied LA and PA in the cerebral microcirculation using intravital fluorescent video microscopy (IVM), blood brain barrier (BBB) dysfunction using Evans Blue (EB) leakage method and E‐selectin expression using dual radiolabeling technique in different WT and Adko mice with CLP. Adiponectin deficiency significantly exaggerated LA (WT‐CLP:201 ± 17; Adko‐CLP: ± 53 cells/mm2; P < 0.05) and PA (WT‐CLP:125 ± 17; Adko‐CLP:188 ± 20 cells/mm2; P < 0.05) in cerebral microcirculation, EB leakage (WT‐CLP:10 ± 3.7; Adko‐CLP:24 ± 4.3 ng/g × µl plasma; P < 0.05) and E‐selectin expression (WT‐CLP:0.06 ± 0.11; Adko‐CLP:0.44 ± 0.053 ng/g; P < 0.05) in the brain tissue of the mice with CLP. Furthermore, E‐selectin monoclonal antibody (mAb) treatment attenuated cell adhesion and BBB dysfunction of Adko‐CLP mice. Adiponectin deficiency is associated with exaggerated leukocyte and PA in cerebral microcirculation of mice with CLP via modulation of E‐selectin expression.
Enhanced thermal performances of silicon-on-diamond wafers incorporating ultrathin nanocrystalline diamond and silicon layers: Raman and micro-Raman analysis
Authors: Mazellier Jean-Paul , Mermoux Michel , Andrieu Francois , Widiez Julie , Dechamp Jérôme , Saada Samuel , Lions Mathieu , Hasegawa Masataka , Tsugawa Kazuo , Bergonzo Philippe , Faynot Olivier
Published: October 2011

Silicon-on-diamond (SOD) wafers potentially present thermal advantages over standard silicon-on-insulator (SOI) counterparts based on SiO2 as the buried insulating layer. This work reports the fabrication of high quality SOD wafers by the bond and etch back SOI process. One key parameter in the CVD diamond growth process is the substrate temperature. We focused here on two processes based on either high or low processing temperature to produce nanocrystalline diamond (NCD) on silicon. Both type of NCD films have been analyzed via Raman spectroscopy. Results have been correlated with scanning electron microscopy observations. In a second part, SOD wafers are fabricated and the crystalline quality of the active silicon layer is assessed via Raman measurements and high resolution transmission electron microscopy imaging. It is shown that the growth of diamond did not induce any structural defect or strain in the thin top silicon layer. Eventually, we demonstrate the efficiency of diamond integration thanks to micro-Raman spectroscopy, where the probing laser simultaneously generates Raman signal and controlled local heating. Our SOD wafers evidence a thermal resistance reduction of about 70% compared to conventional SOI materials, with heat source spatial extension in the micron range.
Mapping and statistics of ferroelectric domain boundary angles and types
Authors: Desmarais Joseph , Ihlefeld Jon F. , Heeg Tassilo , Schubert Jürgen , Schlom Darrell G. , Huey Bryan D.
Published: October 2011

Ferroelectric domain orientations have been mapped using piezo-force microscopy, allowing the calculation and statistical analysis of interfacial polarization angles, the head-to-tail or head-to-head configuration, and any cross-coupling terms. Within 1 µm2 of an epitaxial (001)p-oriented BiFeO3 film, there are >40 µm of linear domain boundary based on over 500 interfaces. 71° domain walls dominate the interfacial polarization angles, with a 2:1 preference for uncharged head-to-tail versus charged head-to-head boundary types. This mapping technique offers a unique perspective on domain boundary distributions, important for ferroelectric and multiferroic applications where domain wall parameters are critical.
Noise reduction by recycling dynamically coupled time series
Authors: Mera M. Eugenia , Morán Manuel
Published: October 2011

We say that several scalar time series are dynamically coupled if they record the values of measurements of the state variables of the same smooth dynamical system. We show that much of the information lost due to measurement noise in a target time series can be recovered with a noise reduction algorithm by crossing the time series with another time series with which it is dynamically coupled. The method is particularly useful for reduction of measurement noise in short length time series with high uncertainties.
An extended scenario for the Schrödinger equation
Authors: Çapak M. , Cançelik Y. , Ünsal Ö. L. , Atay Ş. , Gönül B.
Published: October 2011

The concept of the elegant work introduced by Lévai [J. Phys. A 22, 689 (1989)] is extended for the solutions of the Schrödinger equation with more realistic other potentials used in different disciplines of physics. The connection between the present model and the other alternative algebraic technique in the literature is discussed.
Magnetic confinement of a high-density cylindrical plasma
Authors: Ahedo Eduardo
Published: October 2011

The stationary structure of a weakly collisional plasma column, confined by an axial magnetic field and a cylindrical vessel, is studied for the high-density case, when the diamagnetic azimuthal current is large enough to demagnetize partially the plasma. The plasma response is characterized mainly by two dimensionless parameters: the ratios of the electron gyroradius and the electron skin-depth to the plasma radius, and each of them measures the independent influence of the applied magnetic field and the plasma density on the plasma response. The strong magnetic confinement regime, characterized by very small wall losses, is limited to the small gyroradius and large skin-depth ranges. In the high-density case, when the electron skin-depth is smaller than the electron gyroradius, the skin-depth turns out to be the magnetic screening length, so that the bulk of the plasma behaves as unmagnetized.
Two-fluid electromagnetic simulations of plasma-jet acceleration with detailed equation-of-state
Authors: Thoma C. , Welch D. R. , Clark R. E. , Bruner N. , MacFarlane J. J. , Golovkin I. E.
Published: October 2011

We describe a new particle-based two-fluid fully electromagnetic algorithm suitable for modeling high density (ni ∼ 1017 cm−3) and high Mach number laboratory plasma jets. In this parameter regime, traditional particle-in-cell (PIC) techniques are challenging due to electron timescale and lengthscale constraints. In this new approach, an implicit field solve allows the use of large timesteps while an Eulerian particle remap procedure allows simulations to be run with very few particles per cell. Hall physics and charge separation effects are included self-consistently. A detailed equation of state (EOS) model is used to evolve the ion charge state and introduce non-ideal gas behavior. Electron cooling due to radiation emission is included in the model as well. We demonstrate the use of these new algorithms in 1D and 2D Cartesian simulations of railgun (parallel plate) jet accelerators using He and Ar gases. The inclusion of EOS and radiation physics reduces the electron temperature, resulting in higher calculated jet Mach numbers in the simulations. We also introduce a surface physics model for jet accelerators in which a frictional drag along the walls leads to axial spreading of the emerging jet. The simulations demonstrate that high Mach number jets can be produced by railgun accelerators for a variety of applications, including high energy density physics experiments.
Combinatorial games with a pass: A dynamical systems approach
Authors: Morrison Rebecca E. , Friedman Eric J. , Landsberg Adam S.
Published: October 2011

By treating combinatorial games as dynamical systems, we are able to address a longstanding open question in combinatorial game theory, namely, how the introduction of a “pass” move into a game affects its behavior. We consider two well known combinatorial games, 3-pile Nim and 3-row Chomp. In the case of Nim, we observe that the introduction of the pass dramatically alters the game’s underlying structure, rendering it considerably more complex, while for Chomp, the pass move is found to have relatively minimal impact. We show how these results can be understood by recasting these games as dynamical systems describable by dynamical recursion relations. From these recursion relations, we are able to identify underlying structural connections between these “games with passes” and a recently introduced class of “generic (perturbed) games.” This connection, together with a (non-rigorous) numerical stability analysis, allows one to understand and predict the effect of a pass on a game.
A liquid crystal-based dynamically tunable photonic bandgap structure
Authors: Schaub D. E. , Oliver D. R.
Published: October 2011

A tunable linear photonic bandgap device based on a silicon/liquid crystal dielectric combination has been designed and fabricated. The design features a microstrip line, whose substrate of periodically spaced silicon squares in BL006 (a nematic liquid crystal mixture) induces a bandgap that contracts in response to a low-frequency voltage. Numerical band structure calculations and finite element simulations of the fabricated device showed a bandgap tuning of approximately 10% for the lattice geometries employed. The measured scattering parameters agreed very well with simulations and demonstrated significant tuning of the first bandgap in the range of 6.5–8.4 GHz.
Relaxor behavior in multiferroic BiMn2O5 ceramics
Authors: Fier I. , Walmsley L. , Souza J. A.
Published: October 2011

In polycrystalline BiMn2O5, a broad thermal stimulated depolarization current curve has been observed in the range from 10 K to 300 K and the pyroelectric coefficient determined. In magnetic susceptibility measurements reported in the literature, features appearing in the pyroelectric coefficient could also be identified for the same temperatures, suggesting a connection between electric and magnetic data above the Néel temperature. A detailed study of the dielectric constant from 240 K to 700 K for an extended range of frequencies revealed a broad maximum at low frequencies, characteristic of relaxor ferroelectrics, following Vogel-Fulcher relation. A freezing temperature of the polar nanoregions Tf = 512 K has been determined. This high temperature ferroelectric behavior is attributed to the Bi3+ in the distorted BiO8 cage.
Hydrostatic pressure effect on the martensitic transition, magnetic, and magnetocaloric properties in Ni50-xMn37+xSn13 Heusler alloys
Authors: Esakki Muthu S. , Rama Rao N. V. , Manivel Raja M. , Arumugam S. , Matsubayasi K. , Uwatoko Y.
Published: October 2011

We report upon the effect of hydrostatic pressure on the martensitic transition, magnetic properties, and magnetic entropy change in Ni50-xMn37 + xSn13 (x = 2, 3) Heusler alloys. The application of pressure has significantly shifted the martensitic transition temperature to higher values. A large rate of change of the martensitic transition with a pressure of ∼3.1 K/kbar has been obtained for the x = 2 alloy, whereas the Curie temperature changes marginally with pressure (∼0.3 K/kbar). Magnetization of both the austenite and martensite phases decreases with an increase of pressure. The maximum magnetic entropy change of 34 J kg−1K−1 at ambient pressure and 22.5 J kg−1K−1 at 8 kbar was observed around the martensitic transition temperature for the x = 3 alloy.
Thermal equations of state and phase relation of PbTiO3: A high P-T synchrotron x-ray diffraction study
Authors: Zhu Jinlong , Xu Hongwu , Zhang Jianzhong , Jin Changqing , Wang Liping , Zhao Yusheng
Published: October 2011

The phase relation of tetragonal and cubic PbTiO3 and their unit-cell parameters have been determined by synchrotron x-ray diffraction at pressures up to 7.8 GPa and temperatures up to 1074 K with a cubic anvil apparatus. From these measurements, a pressure-temperature phase boundary between the tetragonal and cubic phases has been established. With increasing temperature or pressure, the c/a ratio of the ferroelectric, tetragonal PbTiO3 becomes closer to unity, suggesting that both heating and compression favor the paraelectric, cubic structure. Using a modified high-T Birch-Murnaghan equation of state and a thermal-pressure approach, we have derived the thermoelastic parameters of tetragonal and cubic PbTiO3, including the ambient bulk modulus K0, temperature derivative of bulk modulus at constant pressure, volumetric thermal expansivity, pressure derivative of thermal expansion, and temperature derivative of bulk modulus at constant volume. Our obtained K0 value for tetragonal PbTiO3 is consistent with previously reported results, while that for cubic PbTiO3 is smaller than earlier results probably due to differences in the experimental techniques used (cubic anvil apparatus versus diamond anvil cell) and related stress conditions of the samples. All other thermoelastic parameters for both tetragonal and cubic PbTiO3 have been determined for the first time. Compared with previous high-temperature data at atmospheric pressure, our P-V-T dataset for tetragonal PbTiO3 infers a pressure-induced crossover in volumetric thermal expansion from negative to positive between 0 and 1 GPa, an phenomenon that is of fundamentally interest and practically important.
On the dynamics of the space-charge layer inside the nozzle of a cutting torch and its relation with the “non-destructive” double-arcing phenomenon
Authors: Prevosto L. , Kelly H. , Mancinelli B.
Published: October 2011

Experimental observations on the plasma dynamics inside the nozzle of a 30 A oxygen cutting torch operated at conditions close to the double arcing are reported. It is employed a technique previously developed in our laboratory consisting in using the nozzle as a large-sized Langmuir probe. Based on the behavior of the ion current signal and simple estimations, it is concluded that (1) the non-equilibrium plasma inside the nozzle is far from the steady state in time, in contrast to what is frequently assumed. The power supply ripple was identified as the main fluctuations source and (2) large-scale plasma fluctuations inside the nozzle could cause transient (total duration of the order of 100 μs) Townsend avalanches developing in the space-charge layer located between the arc plasma and the nozzle wall. Such events trigger the so called non-destructive double-arcing phenomena without appealing to the presence of insulating films deposited inside the nozzle orifice, as was previously proposed in the literature.
Magnetic properties of Fe and Co codoped SnO2 prepared by sol-gel method
Authors: Nomura K. , Okabayashi J. , Okamura K. , Yamada Y.
Published: October 2011

SnO2 codoped with Fe and Co was prepared using the sol-gel method. Compared with SnO2 doped with only Fe or Co, the ferromagnetic saturation magnetization of the codoped SnO2 was enhanced because of the lattice distortion induced by codoping. Mössbauer spectra consist of two paramagnetic doublets and one broad sextet of high-spin Fe(III) species. The Mössbauer spectra revealed that the magnetic sextet with broad peaks is drastically modulated by doping with 0.5%–3% Co and 1% Fe codoped SnO2. Our experimental results suggest correlation between the enhancement of the saturation magnetization and the appearance of sextet peaks.
Designing acoustic transformation devices using fluid homogenization of an elastic substructure
Authors: Layman Christopher N. , Martin Theodore P. , Moore Kimberly M. , Calvo David C. , Orris Gregory J.
Published: October 2011

The design of devices using finite embedded coordinate transformations presents an unique approach to control acoustic waves. Though combining the use of conformal mappings may provide a pathway to more realizable material properties, many device geometries still require combinations of density and sound speed which are unavailable in isotropic materials. Here, we present a design strategy based on a multiple scattering homogenization method to approximate the unique values required within such a device. We apply the method, using full-wave simulations, to the design of an aqueous cylindrical-to-plane wave lens, which can be constructed from simple materials.
Josephson amplifier for qubit readout
Authors: Abdo Baleegh , Schackert Flavius , Hatridge Michael , Rigetti Chad , Devoret Michel
Published: October 2011

We report on measurements of a Josephson amplifier (J-amp) suitable for quantum-state qubit readout in the microwave domain. It consists of two microstrip resonators which intersect at a Josephson ring modulator. A maximum gain of about 20 dB, a bandwidth of 9 MHz, and a center-frequency tunability of about 60 MHz with gain in excess of 10 dB have been attained for idler and signal of frequencies 6.4 GHz and 8.1 GHz, in accordance with theory. Maximum input power measurements of the J-amp show a relatively good agreement with theoretical prediction. We discuss how the amplifier characteristics can be improved.
Carotenoids in nature: insights from plants and beyond
Authors: Cazzonelli Christopher I.
Published: October 2011

Carotenoids are natural isoprenoid pigments that provide leaves, fruits, vegetables and flowers with distinctive yellow, orange and some reddish colours as well as several aromas in plants. Their bright colours serve as attractants for pollination and seed dispersal. Carotenoids comprise a large family of C40 polyenes and are synthesised by all photosynthetic organisms, aphids, some bacteria and fungi alike. In animals carotenoid derivatives promote health, improve sexual behaviour and are essential for reproduction. As such, carotenoids are commercially important in agriculture, food, health and the cosmetic industries. In plants, carotenoids are essential components required for photosynthesis, photoprotection and the production of carotenoid-derived phytohormones, including ABA and strigolactone. The carotenoid biosynthetic pathway has been extensively studied in a range of organisms providing an almost complete pathway for carotenogenesis. A new wave in carotenoid biology has revealed implications for epigenetic and metabolic feedback control of carotenogenesis. Developmental and environmental signals can regulate carotenoid gene expression thereby affecting carotenoid accumulation. This review highlights mechanisms controlling (1) the first committed step in phytoene biosynthesis, (2) flux through the branch to synthesis of α- and β-carotenes and (3) metabolic feedback signalling within and between the carotenoid, MEP and ABA pathways.
Evidence of cellulose metabolism by the giant panda gut microbiome
Authors: Zhu Lifeng , Wu Qi , Dai Jiayin , Zhang Shanning , Wei Fuwen
Published: October 2011

The giant panda genome codes for all necessary enzymes associated with a carnivorous digestive system but lacks genes for enzymes needed to digest cellulose, the principal component of their bamboo diet. It has been posited that this iconic species must therefore possess microbial symbionts capable of metabolizing cellulose, but these symbionts have remained undetected. Here we examined 5,522 prokaryotic ribosomal RNA gene sequences in wild and captive giant panda fecal samples. We found lower species richness of the panda microbiome than of mammalian microbiomes for herbivores and nonherbivorous carnivores. We detected 13 operational taxonomic units closely related to
Clostridium
groups I and XIVa, both of which contain taxa known to digest cellulose. Seven of these 13 operational taxonomic units were unique to pandas compared with other mammals. Metagenomic analysis using ∼37-Mbp contig sequences from gut microbes recovered putative genes coding two cellulose-digesting enzymes and one hemicellulose-digesting enzyme, cellulase, β-glucosidase, and xylan 1,4-β-xylosidase, in
Clostridium
group I. Comparing glycoside hydrolase profiles of pandas with those of herbivores and omnivores, we found a moderate abundance of oligosaccharide-degrading enzymes for pandas (36%), close to that for humans (37%), and the lowest abundance of cellulases and endohemicellulases (2%), which may reflect low digestibility of cellulose and hemicellulose in the panda's unique bamboo diet. The presence of putative cellulose-digesting microbes, in combination with adaptations related to feeding, physiology, and morphology, show that giant pandas have evolved a number of traits to overcome the anatomical and physiological challenge of digesting a diet high in fibrous matter.
Temporal clustering of tropical cyclones and its ecosystem impacts
Authors: Mumby Peter J. , Vitolo Renato , Stephenson David B.
Published: October 2011

Tropical cyclones have massive economic, social, and ecological impacts, and models of their occurrence influence many planning activities from setting insurance premiums to conservation planning. Most impact models allow for geographically varying cyclone rates but assume that individual storm events occur randomly with constant rate in time. This study analyzes the statistical properties of Atlantic tropical cyclones and shows that local cyclone counts vary in time, with periods of elevated activity followed by relative quiescence. Such temporal clustering is particularly strong in the Caribbean Sea, along the coasts of Belize, Honduras, Costa Rica, Jamaica, the southwest of Haiti, and in the main hurricane development region in the North Atlantic between Africa and the Caribbean. Failing to recognize this natural nonstationarity in cyclone rates can give inaccurate impact predictions. We demonstrate this by exploring cyclone impacts on coral reefs. For a given cyclone rate, we find that clustered events have a less detrimental impact than independent random events. Predictions using a standard random hurricane model were overly pessimistic, predicting reef degradation more than a decade earlier than that expected under clustered disturbance. The presence of clustering allows coral reefs more time to recover to healthier states, but the impacts of clustering will vary from one ecosystem to another.
An ATP-binding cassette transporter-like complex governs cell-wall hydrolysis at the bacterial cytokinetic ring
Authors: Yang Desirée C. , Peters Nick T. , Parzych Katherine R. , Uehara Tsuyoshi , Markovski Monica , Bernhardt Thomas G.
Published: October 2011

ATP-binding cassette transporters are ubiquitous membrane protein complexes that move substrates across membranes. They do so using ATP-induced conformational changes in their nucleotide-binding domains to alter the conformation of the transport cavity formed by their transmembrane domains. In
Escherichia coli
, an ATP-binding cassette transporter-like complex composed of FtsE (nucleotide-binding domain) and FtsX (transmembrane domain) has long been known to be important for cytokinesis, but its role in the process has remained mysterious. Here we identify FtsEX as a regulator of cell-wall hydrolysis at the division site. Cell-wall material synthesized by the division machinery is shared initially by daughter cells and must be split by hydrolytic enzymes called “amidases” to drive daughter-cell separation. We recently showed that the amidases require activation at the cytokinetic ring by proteins with LytM domains, of which EnvC is the most critical. In this report, we demonstrate that FtsEX directly recruits EnvC to the septum via an interaction between EnvC and a periplasmic loop of FtsX. Importantly, we also show that FtsEX variants predicted to be ATPase defective still recruit EnvC to the septum but fail to promote cell separation. Our results thus suggest that amidase activation via EnvC in the periplasm is regulated by conformational changes in the FtsEX complex mediated by ATP hydrolysis in the cytoplasm. Since FtsE has been reported to interact with the tubulin-like FtsZ protein, our model provides a potential mechanism for coupling amidase activity with the contraction of the FtsZ cytoskeletal ring.