bluuebunny/crossref_metadata_2025 huggingface dataset:
Voice onset time in Persian initial and intervocalic stop production
Authors: Bijankhan Mahmood , Nourbakhsh Mandana
Published: November 2009

The purpose of this study is to examine voice onset time as a phonetic correlate of voicing distinction in standard Persian. Issues pertinent to VOT are also addressed: namely, the effect of place of articulation, vowel context and sex of speakers. The VOTs were measured from recordings of five male and five female speakers reading 65 words that contained a full set of Persian oral stops in word initial and intervocalic positions. This acoustic experiment indicated that VOT distinguishes voiced from voiceless stops. The results also revealed that Persian uses mainly {voiceless unaspirated} and {voiceless aspirated} categories for [±voice] distinction in initial position and {voiced} and {voiceless aspirated} categories in intervocalic position. Vowel context also affected VOT values but the only significant difference was due to high vowels, which caused the preceding voiceless stop to have a longer VOT. Examining sex differences in the VOT values indicated that for voiced items females produced longer VOTs than males. However, voiceless items displayed no significant sex differences for VOT values. Fundamental frequency (F0) of the onset of the following vowel was also examined as another cue to voice distinction. Although the F0 values of voiceless tokens were higher than those of the voiced ones in each voiced–voiceless category, the results suggest that F0 is not a major cue distinguishing the two stop categories.
Nepali
Authors: Khatiwada Rajesh
Published: November 2009

Nepali, a language of the Indo-Aryan family, is the official language of Nepal. According to the 2001 population census of Nepal, more than 11 million Nepalese (48.61% of the total population) claim this language as their mother tongue. It is also spoken in other countries of South Asia, such as India and Bhutan, as well as by members of the Nepalese Diaspora around the world. The population census of India of 1991 reported that more than two million Indians use Nepali as their mother tongue. Within Nepal, Nepali shows some dialectal variation mainly linked to geographical and socio-cultural factors. Nevertheless, the dialect called the ‘eastern’ dialect spoken by a majority of Nepali speakers shows rather little variation (Bandhu et al. 1971).
In Memoriam: Ralph L. Vanderslice and Gunnar Fant
Authors: Ohala John J. , Bruce Gösta
Published: November 2009

RALPH L. VANDERSLICE, who contributed to many areas of phonetics, died on 24 August 2008, aged 78, in Portland, Oregon. He was born on 2 January 1930 in South Bend, Indiana. He received his B.A. and his M.Sc. in speech and theatre from Michigan State College (now Michigan State University) in 1951 and 1954, respectively. He subsequently taught at the Universities of Vermont and Hawai'i. He moved to UCLA where, in 1968, he obtained his Ph.D. His dissertation, Synthetic Elocution (http://repositories.cdlib.org/uclaling/wpp/No8/), was an exploration of the character and some of the specifics of the rules that would be necessary to implement the prosodic aspects of synthesized speech produced by a reading machine. Peter Ladefoged was the chair of his dissertation committee and Victoria Fromkin one of the other members. While still a student at UCLA Ralph Vanderslice was an expert witness testifying against the validity of ‘voiceprints’ (the use of spectrographic displays of speech to identify suspects in criminal trials). He was very much a ‘hands-on’ person, skilled in many of the mechanical and electronic arts, one manifestation of this being his invention of the ‘crico-thyrometer’, a device that could track vertical larynx movement in connected speech. He subsequently taught at City University of New York and Yale University. He published many papers on speech prosody, notably ‘Binary suprasegmental features and transformational word-accentuation rules’ (1972, Language, with Peter Ladefoged). His colleagues, including this author, his office-mate in the UCLA Phonetics Lab, remember him for his erudition, wit, and generosity in helping others with everything from providing references to the seventeenth- and eighteenth-century works on phonetics (which he was steeped in) to repairing a shorted circuit in an amplifier. His salutary influence continues.
REPRESENTATION c. 800: ARAB, BYZANTINE, CAROLINGIAN
Authors: Brubaker Leslie
Published: November 2009

What could or should be visually represented was a contested issue across the medieval Christian and Islamic world around the year 800. This article examines how Islamic, Byzantine, Carolingian and Palestinian Christian attitudes toward representation were expressed, and differed, across the seventh and eighth centuries. Islamic prohibitions against representing human figures were not universally recognised, but were particularly – if sometimes erratically – focused on mosque decoration. Byzantine ‘iconoclasm’ – more properly called iconomachy – was far less destructive than its later offshoots in France and England, and resulted in a highly nuanced re-definition of what representation meant in the Orthodox church. Carolingian attitudes toward images were on the whole far less passionate than either Islamic or Orthodox views, but certain members of the elite had strong views, which resulted in particular visual expressions. Palestinian Christians, living under Islamic rule, modulated their attitudes toward images to conform with local social beliefs. Particularly in areas under Orthodox or Islamic control, then, representation mattered greatly around the year 800, and this article examines how and why this impacted on local production.
Limit cycles of the generalized polynomial Liénard differential equations
Authors: LLIBRE JAUME , MEREU ANA CRISTINA , TEIXEIRA MARCO ANTONIO
Published: November 2009

We apply the averaging theory of first, second and third order to the class of generalized polynomial Liénard differential equations. Our main result shows that for any n, m ≥ 1 there are differential equations of the form ẍ + f(x)ẋ + g(x) = 0, with f and g polynomials of degree n and m respectively, having at least [(n + m − 1)/2] limit cycles, where [·] denotes the integer part function.
A Conflict in Common-Sense Moral Psychology
Authors: ZIMMERMAN AARON Z.
Published: November 2009

Ordinary thinking about morality and rationality is inconsistent. To arrive at a view of morality that is as faithful to common thought as consistency will allow we must admit that it is not always irrational to knowingly act against the weight of reasons.
Is Situationism All Bad News?
Authors: RUSSELL LUKE
Published: November 2009

Situationist experiments such as the Milgram experiment and the Princeton Seminary experiment have prompted philosophers to warn us against succumbing to fear of embarrassment and sliding down slippery slopes. Yet it would be a mistake to conclude that situationism is all bad news for moral agents. Fear of embarrassment can often motivate right actions, and slippery slopes can slide us away from wrongdoing. The reason that philosophers have seen situationism as bringing all bad news is that they have focused on the very demanding moral goals of virtuous and autonomous action, while ignoring important moral goals that are less demanding. Fear of embarrassment does undermine virtuous and autonomous action, but that very same fear can help us to act resolutely and rightly, and allows us to manipulate would-be wrongdoers into doing the right thing. This is good news.
On Three Alleged Theories of Rational Behavior
Authors: RACHELS STUART
Published: November 2009

What behavior is rational? It's rational to act ethically, some think. Others endorse instrumentalism – it is rational to pursue one's goals. Still others say that acting rationally always involves promoting one's self-interest. Many philosophers have given each of these answers. But these answers don't really conflict; they aren't vying to describe some shared concept or to solve some mutually acknowledged problem. In so far as this is debated, it is a pseudo-debate. The different uses of ‘rational action’ differ merely in meaning. I shall defend the following claims: ‘rational behavior’ is used in ethical, prudential, and instrumental ways (section I); these uses of ‘rational behavior’ are distinct (section II); they do not represent competing theories of rational behavior (section III); we should stop using ‘rational behavior’ ethically and prudentially, but we may continue its instrumental use (section IV).
The cultural politics of Dido and Aeneas
Authors: WELCH ANTHONY
Published: November 2009

Controversial efforts to find political allegory in Dido and Aeneas (c.1689), the great chamber opera by Nahum Tate and Henry Purcell, have obscured the opera's broader concern with the politics of culture. As rival political factions claimed ownership of the nation's cultural heritage, Tate and other dramatists in Restoration England asked searching questions about the relationship between the artist and political authority. Grappling with Virgil's Aeneid, a central text of Stuart absolutism, Dido and Aeneas explores the workings and the costs of partisan myth-making. The opera joins many other Restoration voices in taking up an ancient ‘chaste Dido’ tradition, which accused Virgil of mangling Dido's historical reputation in the service of imperial propaganda. Yet Dido does not set forth a topical allegory or a coherent critique of Stuart misrule, but takes an unstable, irresolute attitude towards the cultural legacy of Virgil, the aesthetics of female suffering, and the politics of royal praise.
Rossini's noisy bodies
Authors: ESSE MELINA
Published: November 2009

Rossini's comic finales consistently foreground the propensity of noise to overwhelm the senses, to both signify and induce madness or confusion, and to transform the bodies on stage into noisy automata. Such mechanical noisiness may appear ‘naturally’ comic and dramatically appropriate – and therefore hardly in need of comment. But the din of Rossini's operas was a point of contention for critics; even Stendhal, normally the composer's staunch advocate, displays a kind of ambivalence about the sheer physical force of Rossini's music. This ambivalence mirrors a larger division between fans and critics, a bifurcation that produced an immense volume of printed matter as Rossini's music became a nexus for debates about the place of reason versus sensation and the troubled relationship between physiological and moral stimulation. These tensions are especially apparent in two operas from 1817, La Cenerentola and La gazza ladra. Both works tend to subvert the conventions of sentimental comedy by ironizing sentimental display, mocking tender feelings or, most tellingly, juxtaposing tears with violent cacophony – tactics that did not always sit well with critics. Using Stendhal's Vie de Rossini as a focal point, this essay situates Rossinian noise and the controversy surrounding it in the context of pervasive concern about the sensible body in a post-sentimental era. Because it seemed to act on the body in such powerful ways, noise very easily allowed commentators to invoke a whole panoply of overlapping discourses – of politics, sentimentality and sensibility, morality, medicine and physiology – in their attempts to account for Rossini's popularity.
Interpretative communities as decisive agents: on pervasive digital technologies
Authors: Coyne Richard
Published: November 2009

The emergence of computer-mediated social networking amplifies concepts of shared and diffused agency. It seems that much is accomplished not so much by individuals standing out against the crowd, but by crowds of people forming, re-forming, interacting and sharing through highly responsive electronic media. So-called ‘smart mobs’ are apparently capable of generating meaningful outcomes by collective action through mobile phones, social networks such as Facebook, and shared open-source enterprises as in open software development. Contemporary theorising in the fields of human-computer interaction and digital media promotes concepts of ubiquitous, egalitarian, democratic, grass-roots, collective agency above concepts of hierarchical, heroic and individual creation, a shift thought by some to challenge accepted ways of designing and occupying space.
Spatial agency: tactics of self-organisation
Authors: Vardy Sam
Published: November 2009

This paper sets out to introduce the notion of self-organisation in spatial, social and political terms, as a form of spatial agency in response to issues of subjectivity and the politics of urban space. Self-organisation – a complex notion, with multiple and sometimes contradictory meanings and implications – has gained increased relevance in contemporary political and urban discourses. In this sense, self-organisation can be understood as ‘a collective process of taking on political functions and addressing tasks that have been excluded from the field of real politics or pushed out of public space’. This reading is representative of the view taken here, particularly in its (perhaps unintentional) conflation of the political and the spatial. Indeed, the political functions that it speaks of are also, for this paper, spatial functions; and the field of politics, is also the field of architecture and urban planning.
Taking care of public space
Authors: Schalk Meike , Sustersic Apolonija
Published: November 2009

Through an examination of the public art project Garden Service, in this text we explore possibilities of and obstacles to practices of agency. The project was commissioned by the art institution The Common Guild in Edinburgh for the exhibition Jardins Publics, which took place in connection with the Edinburgh International Festival in summer 2007. It was based on the participation of a community and the communication between different actors, from institutions and associations to individual local residents, communication which included solving conflicts as well as building partnerships.
Revisiting a Vitruvian preface: the value of multiple skills in contemporary architectural pedagogy
Authors: D'souza Newton
Published: November 2009

Recent criticisms in architectural pedagogy suggest that schools of architecture tend to privilege a narrow section of designers with limited skill-sets, neglecting individual differences. In order to encourage architectural pedagogy to become more inclusive, this paper revisits the value of multiple skill-sets in architectural design – following an original suggestion by Vitruvius – exploring it through the framework of multiple intelligences developed by cognitive psychologist Howard Gardner.
Efficient sampling techniques for uncertainty quantification in history matching using nonlinear error models and ensemble level upscaling techniques
Authors: Efendiev Y. , Datta‐Gupta A. , Ma X. , Mallick B.
Published: November 2009

The Markov chain Monte Carlo (MCMC) is a rigorous sampling method to quantify uncertainty in subsurface characterization. However, the MCMC usually requires many flow and transport simulations in evaluating the posterior distribution and can be computationally expensive for fine‐scale geological models. We propose a methodology that combines coarse‐ and fine‐scale information to improve the efficiency of MCMC methods. The proposed method employs off‐line computations for modeling the relation between coarse‐ and fine‐scale error responses. This relation is modeled using nonlinear functions with prescribed error precisions which are used in efficient sampling within the MCMC framework. We propose a two‐stage MCMC where inexpensive coarse‐scale simulations are performed to determine whether or not to run the fine‐scale (resolved) simulations. The latter is determined on the basis of a statistical model developed off line. The proposed method is an extension of the approaches considered earlier where linear relations are used for modeling the response between coarse‐scale and fine‐scale models. The approach considered here does not rely on the proximity of approximate and resolved models and can employ much coarser and more inexpensive models to guide the fine‐scale simulations. Numerical results for three‐phase flow and transport demonstrate the advantages, efficiency, and utility of the method for uncertainty assessment in the history matching.
Carbon and hydrogen isotopic composition of methane over the last 1000 years
Authors: Mischler J. A. , Sowers T. A. , Alley R. B. , Battle M. , McConnell J. R. , Mitchell L. , Popp T. , Sofen E. , Spencer M. K.
Published: November 2009

New measurements of the carbon and hydrogen isotopic ratios of methane (δ13C of CH4 and δD of CH4) over the last millennium are presented from the WAIS Divide, Antarctica, ice core (WDC05A), showing significant changes that likely were the result of human influences prior to the industrial revolution (at least as early as the 16th century of the common era (CE)). The δ13C of CH4 data corroborate the record from Law Dome, Antarctica, with high fidelity. The new δD of CH4 data set covaries with the δ13C of CH4 record. Both δ13C of CH4 and δD of CH4 were relatively stable and close to the present‐day values from ∼1000 to ∼1500 CE. Both isotopic ratios decreased to minima around 1700 CE, remained low until the late 18th century, and then rose exponentially to present‐day values. Our new δD of CH4 data provide an additional independent constraint for evaluating possible CH4 source histories. We searched a broad range of source scenarios using a simple box model to identify histories consistent with the constraints of the CH4 concentration and isotope data from 990–1730 CE. Results typically show a decrease over time in the biomass‐burning source (found in 85% of acceptable scenarios) and an increase in the agricultural source (found in 77% of acceptable scenarios), indicating preindustrial human influence on atmospheric methane as proposed in previous studies.
Eikonal acceleration technique for studying of the Earth and planetary atmospheres by radio occultation method
Authors: Pavelyev A. G. , Liou Y. A. , Wickert J. , Gavrik A. L. , Lee C. C.
Published: November 2009

Lately introduced a phase (eikonal) acceleration technique extends an applicable domain of radio occultation (RO) method and can be applied for identification of the plasma layers in the lower ionosphere. This technique can also convert the eikonal excess or Doppler frequency changes measured in RO experiments into the refractive attenuation variations. From these derived refractive attenuation and amplitude data one can estimate the integral absorption of radio waves. This is important for study of the radio wave propagation effects in the atmospheric telecommunication links and for remote sensing of the atmosphere and ionosphere. The advantages of the eikonal acceleration technique are validated by analyzing the RO data from the Challenging Minisatellite Payload (CHAMP) and Venus missions.
CO2 and CH4 fluxes during spring and autumn mixing periods in a boreal lake (Pääjärvi, southern Finland)
Authors: López Bellido Jessica , Tulonen Tiina , Kankaala Paula , Ojala Anne
Published: November 2009

The greatest gas loss from dimictic lakes occur during spring and autumn mixing periods. Thus, we measured daily concentration gradients of carbon gases (CO2 and CH4) in mesohumic Lake Pääjärvi during the mixing periods in autumn 2004 and spring 2005 and calculated and compared the fluxes using three different methods: the boundary layer diffusion model (ΔCO2 and ΔCH4), floating static chambers (FC), and changes in gas storage. CO2 fluxes were higher in autumn than in spring, whereas CH4 fluxes were lower in autumn than in spring. The method based on changes in storage underestimated the fluxes whereas the floating chambers and the boundary layer diffusion models resulted in similar estimates. However, the chambers always yielded somewhat higher fluxes. Total ΔCO2 flux in autumn was 883 mmol m−2 and in spring, 666 mmol m−2, whereas total ΔCH4 fluxes were 0.60 mmol m−2 and 0.80 mmol m−2 in autumn and spring, respectively. We calculated gas transfer velocities (k600) to explain the near surface exchange mechanism and the difference between the results based on diffusion models and chambers. Wind speed and k600 showed significant correlation. In spring the transfer velocity at similar wind speed was higher compared to the autumn. Weekly measurements of algal primary production and community respiration revealed that the lake was net heterotrophic in autumn as well as in spring. Our study showed that the excess CO2 from the lake metabolism contributed significantly to the CO2 fluxes during the mixing periods, violating the primary assumption used in the storage method.
Efficient aquatic bacterial metabolism of dissolved low-molecular-weight compounds from terrestrial sources
Authors: Berggren Martin , Laudon Hjalmar , Haei Mahsa , Ström Lena , Jansson Mats
Published: November 2009

Carboxylic acids (CAs), amino acids (AAs) and carbohydrates (CHs) in dissolved free forms can be readily assimilated by aquatic bacteria and metabolized at high growth efficiencies. Previous studies have shown that these low-molecular-weight (LMW) substrates are released by phytoplankton but also that unidentified LMW compounds of terrestrial origin is a subsidy for bacterial metabolism in unproductive freshwater systems. We tested the hypothesis that different terrestrially derived CA, AA and CH compounds can offer substantial support for aquatic bacterial metabolism in fresh waters that are dominated by allochthonous dissolved organic matter (DOM). Drainage water from three catchments of different characters in the Krycklan experimental area in Northern Sweden were studied at the rising and falling limb of the spring flood, using a 2-week bioassay approach. A variety of CA, AA and CH compounds were significantly assimilated by bacteria, meeting 15–100% of the bacterial carbon demand and explaining most of the observed variation in bacterial growth efficiency (BGE; R2=0.66). Of the 29 chemical species that was detected, acetate was the most important, representing 45% of the total bacterial consumption of all LMW compounds. We suggest that LMW organic compounds in boreal spring flood drainage could potentially support all in situ bacterial production in receiving lake waters during periods of weeks to months after the spring flood.
Conversion and conservation of light energy in a photosynthetic microbial mat ecosystem
Authors: Al-Najjar Mohammad A A , de Beer Dirk , Jørgensen Bo Barker , Kühl Michael , Polerecky Lubos
Published: November 2009

Here we present, to the best of our knowledge, the first balanced light energy budget for a benthic microbial mat ecosystem, and show how the budget and the spatial distribution of the local photosynthetic efficiencies within the euphotic zone depend on the absorbed irradiance (Jabs). Our approach uses microscale measurements of the rates of heat dissipation, gross photosynthesis and light absorption in the system, and a model describing light propagation and conversion in a scattering–absorbing medium. The energy budget was dominated by heat dissipation on the expense of photosynthesis: in light-limiting conditions, 95.5% of the absorbed light energy dissipated as heat and 4.5% was channeled into photosynthesis. This energy disproportionation changed in favor of heat dissipation at increasing irradiance, with >99% of the absorbed light energy being dissipated as heat and <1% used by photosynthesis at Jabs>700 μmol photon m−2 s−1 (>150 J m−2 s−1). Maximum photosynthetic efficiencies varied with depth in the euphotic zone between 0.014−0.047 O2 per photon. Owing to steep light gradients, photosynthetic efficiencies varied differently with increasing irradiances at different depths in the euphotic zone; for example, at Jabs>700 μmol photon m−2 s−1, they reached around 10% of the maximum values at depths 0−0.3 mm and progressively increased toward 100% below 0.3 mm. This study provides the base for addressing, in much more detail, the photobiology of densely populated photosynthetic systems with intense absorption and scattering. Furthermore, our analysis has promising applications in other areas of photosynthesis research, such as plant biology and biotechnology.
Heat Acclimation Provides Sustained Improvement in Functional Recovery and Attenuates Apoptosis after Traumatic Brain Injury
Authors: Umschwief Gali , Shein Na'ama A , Alexandrovich Alexander G , Trembovler Victoria , Horowitz Michal , Shohami Esther
Published: November 2009

Heat acclimation (HA) offers functional neuroprotection in mice after traumatic brain injury (TBI). This study further characterizes endogenous neuroprotection acquired by HA (34±1°C, 30 d) after TBI. We establish here the ability of HA to induce sustained functional benefits and to reduce activation of apoptotic pathways. Neurobehavioral recovery, assessed by the Neurological Severity Score, was greater in HA mice up to 8 days after injury as compared with normothermic controls ( P<0.05) and lesion volume was also smaller in the HA group ( P<0.05). Reduced apoptotic cell death in HA mice was confirmed using caspase-3 activity measurements and immunohistochemistry. To investigate the underlying molecular pathways, expression levels of intrinsic apoptotic pathway-related proteins were examined. HA mice displayed higher mitochondrial levels of antiapoptotic Bcl-xL, accompanied by lower proapoptotic Bad levels and decreased cytochrome c release, suggesting a higher apoptotic threshold. Taken together with our previous reports, indicating increased Akt phosphorylation and antioxidative capacity, alongside with reduced tumor necrosis α levels after TBI in HA animals, the current results support the involvement of an antiapoptotic effect in HA-induced neuroprotection. Current results warrant further study as TBI-induced apoptosis may persist over weeks after injury, possibly providing a target for belated therapeutic intervention.
Impact of 6‐month Caloric Restriction on Autonomic Nervous System Activity in Healthy, Overweight, Individuals
Authors: de Jonge Lilian , Moreira Emilia A.M. , Martin Corby K. , Ravussin Eric ,   Pennington CALERIE Team
Published: November 2009

Caloric restriction (CR) increases maximum lifespan but the mechanisms are unclear. Dominance of the sympathetic nervous system (SNS) over the parasympathetic nervous system (PNS) has been shown to be a strong risk factor for cardiovascular disease. Obesity and aging are associated with increased SNS activity, and weight loss and/or exercise seem to have positive effects on this balance. We therefore evaluated the effect of different approaches of CR on autonomic function in 28 overweight individuals participating in the Comprehensive Assessment of Long‐term Effects of Reducing Intake of Energy (CALERIE) trial. Participants were randomized to either control, CR: 25% decrease in energy intake, CREX: 12.5% CR + 12.5% increase in energy expenditure, or LCD: low‐calorie diet until 15% weight reduction followed by weight maintenance. Autonomic function was assessed by spectral analysis of heart‐rate variability (HRV) while fasting and after a meal. Measurements were performed at baseline and 6 months. HR and SNS index decreased and PNS index increased in all intervention groups but reached significance only in CREX. HR and SNS index increased and PNS index decreased in response to the meal in all intervention groups. The results therefore suggest that weight loss improved SNS/PNS balance especially when CR is combined with exercise.
Walnut Consumption Increases Satiation but Has No Effect on Insulin Resistance or the Metabolic Profile Over a 4‐day Period
Authors: Brennan Aoife M. , Sweeney Laura L. , Liu Xiaowen , Mantzoros Christos S.
Published: November 2009

Obesity and diabetes have been associated with increased consumption of highly processed foods, and reduced consumption of whole grains and nuts. It has been proposed, mainly on the basis of observational studies, that nuts may provide superior satiation, may lead to reduced calorie consumption, and may decrease the risk of type 2 diabetes; but evidence from randomized, interventional studies is lacking. A total of 20 men and women with the metabolic syndrome participated in a randomized, double‐blind, crossover study of walnut consumption. Subjects had two 4‐day admissions to the clinical research center where they were fed an isocaloric diet. In addition, they consumed shakes for breakfast containing either walnuts or placebo (shakes were standardized for calories, carbohydrate, and fat content). Appetite, insulin resistance, and metabolic parameters were measured. We found an increased level of satiety (overall P value = 0.0079) and sense of fullness (P = 0.05) in prelunch questionnaires following the walnut breakfast as compared to the placebo breakfast, with the walnut effect achieving significance on day 3 and 4 (P = 0.02 and P = 0.03). We did not find any change in resting energy expenditure, hormones known to mediate satiety, or insulin resistance when comparing the walnut vs. placebo diet. Walnut consumption over 4 days increased satiety by day 3. Long‐term studies are needed to confirm the physiologic role of walnuts, the duration of time needed for these effects to occur, and to elucidate the underlying mechanisms.
Fine‐mapping of Obesity‐related Quantitative Trait Loci in an F9/10 Advanced Intercross Line
Authors: Fawcett Gloria L. , Jarvis Joseph P. , Roseman Charles C. , Wang Bing , Wolf Jason B. , Cheverud James M.
Published: November 2009

Obesity develops in response to a combination of environmental effects and multiple genes of small effect. Although there has been significant progress in characterizing genes in many pathways contributing to metabolic disease, knowledge about the relationships of these genes to each other and their joint effects upon obesity lags behind. The LG,SM advanced intercross line (AIL) model of obesity has been used to characterize over 70 loci involved in fatpad weight, body weight, and organ weights. Each of these quantitative trait loci (QTLs) encompasses large regions of the genome and require fine‐mapping to isolate causative sequence changes and possible mechanisms of action as indicated by the genetic architecture. In this study we fine‐map QTLs first identified in the F2 and F2/3 populations in the combined F9/10 advanced intercross generations. We observed significantly narrowed QTL confidence regions, identified many single QTL that resolve into multiple QTL peaks, and identified new QTLs that may have been previously masked due to opposite gene effects at closely linked loci. We also present further characterization of the pleiotropic and epistatic interactions underlying these obesity‐related traits.
Novel Obesity Risk Loci Do Not Determine Distribution of Body Fat Depots: A Whole‐body MRI/MRS study
Authors: Haupt Axel , Thamer Claus , Heni Martin , Machicao Fausto , Machann Jürgen , Schick Fritz , Stefan Norbert , Fritsche Andreas , Häring Hans‐Ulrich , Staiger Harald
Published: November 2009

A recent meta‐analysis of genome‐wide association studies has identified six new risk‐loci for common obesity. We studied whether these risk loci influence the distribution of body fat depots. We genotyped 1,469 nondiabetic subjects for the single‐nucleotide polymorphisms (SNPs) TMEM18 rs6548238, KCTD15 rs11084753, GNPDA2 rs10938397, SH2B1 rs7498665, MTCH2 rs10838738, and NEGR1 rs2815752. We assessed BMI, waist circumference, total body fat, and lean body mass (bioimpedance). All subjects underwent an oral glucose tolerance test (OGTT) for estimation of insulin sensitivity. In 332 subjects, we measured total adipose tissue (TAT), visceral adipose tissue (VAT), nonvisceral adipose tissue (NVAT), liver fat content, and intramyocellular lipids (IMCLs) using whole‐body magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). In the dominant inheritance model, the risk alleles of TMEM18 rs6548238 and MTCH2 rs10838738 were nominally associated with higher BMI (P = 0.04, both). The risk allele of TMEM18 rs6548238 was additionally associated with higher waist circumference and total body fat (P ≤ 0.03), the risk allele of NEGR1 rs2815752 with higher waist circumference (P = 0.05) and unexpectedly with lower BMI (P = 0.01). In the MR cohort, we found an association of the risk allele of SH2B1 rs7498665 with higher VAT (P = 0.009) and of GNPDA2 rs10938397 with increased IMCLs (P = 0.03). After Bonferroni correction for multiple comparisons (corrected α‐level: P = 0.0085), none of the SNPs was significantly associated with measures of adiposity or body fat distribution (all P > 0.009, dominant inheritance model). Therefore, our results suggest that these new obesity SNPs, despite their influence on BMI, are neither associated with a metabolically unfavorable nor with a favorable body composition.
Magnetic properties and large magnetocaloric effect of DyPt2
Authors: Arora Parul , Chattopadhyay M. K. , Roy S. B.
Published: November 2009

We report the results of magnetization and heat capacity measurements on the rare-earth intermetallic compound DyPt2 as a function of temperature and magnetic field. These studies reveal the presence of short range magnetic correlations in DyPt2 above the Curie temperature, well inside the paramagnetic regime. This contributes appreciably to the magnetic entropy, which can be tuned with the help of applied magnetic field over a wide range of temperature. As a result, DyPt2 exhibits a large magnetocaloric effect that persists at temperatures much above the Curie temperature.
Whispering-gallery-modelike resonance of luminescence from a single hexagonal ZnO microdisk
Authors: Kim Sung Soo , Kim Yong-Jin , Yi Gyu-Chul , Cheong Hyeonsik
Published: November 2009

We have imaged the luminescence from a single ZnO hexagonal microdisk using a confocal-microscopy-based imaging spectroscopy system. Micro-Raman scattering measurements confirm that the ZnO microdisk was grown with the direction of the c-axis normal to its surface and the Si substrate. The photoluminescence images of the microdisk at room temperature and at low temperature show a donut-shaped intensity profile; the intensity is small near the center and near the edges and is large between the center and the edges. This result is compared with numerical simulations and explained in terms of whispering-gallery-modelike resonances in the microdisk.
Experimental and finite-element method studies of the effects of ferromagnetic substrate on the total ac loss in a rolling-assisted biaxially textured substrate YBa2Cu3O7 tape exposed to a parallel ac magnetic field
Authors: Nguyen Doan N. , Ashworth Stephen P. , Willis Jeffrey O.
Published: November 2009

This paper presents a study of the total ac loss characteristics of a rolling-assisted biaxially textured substrate (RABiTS) YBa2Cu3O7 (YBCO) sample exposed to a parallel ac magnetic field. The results have shown that, for a given applied magnetic field and transport current, a RABiTS YBCO tape can generate very different magnitudes of ac loss, depending on whether the transport current and applied field have the same phase or opposite phase. The results of this study are very important for the optimization of the design of a RABiTS YBCO cable because they can suggest an appropriate arrangement of RABiTS tapes in a cable to minimize the cable ac loss. In this study, both experimental and finite-element method simulation approaches were employed. A modeling model that takes the magnetic field dependent permeability and ferromagnetic loss of the substrate into account reproduced well the experimental data for both self-field and total ac losses.
Solid-liquid phase equilibria of the Gaussian core model fluid
Authors: Mausbach Peter , Ahmed Alauddin , Sadus Richard J.
Published: November 2009

The solid-liquid phase equilibria of the Gaussian core model are determined using the GWTS [J. Ge, G.-W. Wu, B. D. Todd, and R. J. Sadus, J. Chem. Phys. 119, 11017 (2003)] algorithm, which combines equilibrium and nonequilibrium molecular dynamics simulations. This is the first reported use of the GWTS algorithm for a fluid system displaying a reentrant melting scenario. Using the GWTS algorithm, the phase envelope of the Gaussian core model can be calculated more precisely than previously possible. The results for the low-density and the high-density (reentrant melting) sides of the solid state are in good agreement with those obtained by Monte Carlo simulations in conjunction with calculations of the solid free energies. The common point on the Gaussian core envelope, where equal-density solid and liquid phases are in coexistence, could be determined with high precision.
Tunable lattice strain in vertically aligned nanocomposite (BiFeO3)x:(Sm2O3)1−x thin films
Authors: Bi Zhenxing , Lee Joon Hwan , Yang Hao , Jia Quanxi , MacManus-Driscoll Judith L. , Wang Haiyan
Published: November 2009

Unique epitaxial two-phase vertically aligned nanocomposite (VAN) (BiFeO3)x:(Sm2O3)1−x thin films were deposited on SrTiO3(001) substrates by pulsed laser deposition. The VAN thin films exhibit a highly ordered vertical columnar structure with high epitaxial quality. We demonstrate that the strains of the two phases in both out-of-plane and in-plane directions can be tuned by the deposition parameters during growth, e.g., deposition frequency and film composition of the nanocomposite. The strain tunability is found to be directly related to the systematic variation in the column widths in the nanocomposite. The dielectric property measurement shows that increasing vertical strain control will lead to a systematic dielectric loss reduction in the VAN thin films. This study suggests a promising avenue in achieving tunable strain in functional oxide thin films by using VAN structures.
Dynamical systems and Poisson structures
Authors: Gürses Metin , Guseinov Gusein Sh. , Zheltukhin Kostyantyn
Published: November 2009

We first consider the Hamiltonian formulation of n=3 systems, in general, and show that all dynamical systems in R3 are locally bi-Hamiltonian. An algorithm is introduced to obtain Poisson structures of a given dynamical system. The construction of the Poisson structures is based on solving an associated first order linear partial differential equations. We find the Poisson structures of a dynamical system recently given by Bender et al. [J. Phys. A: Math. Theor. 40, F793 (2007)]. Secondly, we show that all dynamical systems in Rn are locally (n−1)-Hamiltonian. We give also an algorithm, similar to the case in R3, to construct a rank two Poisson structure of dynamical systems in Rn. We give a classification of the dynamical systems with respect to the invariant functions of the vector field X⃗ and show that all autonomous dynamical systems in Rn are superintegrable.
High resolution miniature dilatometer based on an atomic force microscope piezocantilever
Authors: Park J.-H. , Graf D. , Murphy T. P. , Schmiedeshoff G. M. , Tozer S. W.
Published: November 2009

Thermal expansion, or dilation, is closely related to the specific heat, and provides useful information regarding material properties. The accurate measurement of dilation in confined spaces coupled with other limiting experimental environments such as low temperatures and rapidly changing high magnetic fields requires a new sensitive millimeter size dilatometer that has little or no temperature and field dependence. We have designed an ultracompact dilatometer using an atomic force microscope piezoresistive cantilever as the sensing element and demonstrated its versatility by studying the charge density waves in alpha uranium to high magnetic fields (up to 31 T). The performance of this piezoresistive dilatometer was comparable to that of a titanium capacitive dilatometer.
Analog-to-digital converters nonlinear errors correction in thermal diagnostics for the laser interferometer space antenna mission
Authors: Sanjuán J. , Lobo A. , Ramos-Castro J.
Published: November 2009

Low-noise temperature measurements at frequencies in the millihertz range are required in the laser interferometer space antenna (LISA) and LISA PathFinder missions. The required temperature stability for LISA is around 10 μK Hz−1/2 at frequencies down to 0.1 mHz. In this paper we focus on the identification and reduction in a source of excess noise detected when measuring time-varying temperature signals. This is shown to be due to nonidealities in the analog-to-digital converter (ADC) transfer curve, and degrades the measurement by about one order of magnitude in the measurement bandwidth when the measured temperature drifts by a few ∼μK s−1. In a suitable measuring system for the LISA mission, this noise needs to be reduced. Two different methods based on the same technique have been implemented, both consisting in the addition of dither signals out of band to mitigate the ADC nonideality errors. Excess noise of this nature has been satisfactorily reduced by using these methods when measuring temperature ramps up to 10 μK s−1.
Super-Poissonian statistics of on-off jumps in blinking fluorescence of single molecules
Authors: Osad’ko I. S.
Published: November 2009

Blinking fluorescence of a single guest molecule embedded in a polymer matrix and excited by cw laser light is considered. Such fluorescence exhibits quantum jumps from bright on-intervals to dark off-intervals, i.e., so-called on→off jumps. A system with one type of on-intervals and with two types of off-intervals is studied. A distribution function wN(T) for the number N of on→off jumps in a time interval T is derived. The distribution function is expressed via a threefold integral of three Poissonian functions, each of which relates to the corresponding exponential process in the quantum dynamics of a fluorescent impurity center. Numerical calculations of the distribution function wN(T) for four time intervals T of various durations are carried out. The distribution function wN(T) is broader as compared with the Poissonian one and has two maxima, one of which relates to observed time intervals without on→off jumps.
Negative ion surface production through sputtering in hydrogen plasma
Authors: Schiesko L. , Carrère M. , Layet J.-M. , Cartry G.
Published: November 2009

A graphite sample is negatively biased in a hydrogen plasma. H− ions created on the surface are accelerated by the sheath toward a mass spectrometer where they are detected according to their energy. The ion distribution function shows two contributions: a main peak followed by an energetic tail. It was previously proven backscattering of positive ions as negative ions is responsible for the high energy tail. In this paper we demonstrate 75% of negative ion surface production is coming from sputtering of adsorbed hydrogen atoms as negative ions. The positive ion energy threshold for this mechanism is around 20 eV and its maximum around 70 eV.
Structural aging and stiction dynamics in confined liquid films
Authors: Yamada Shinji
Published: November 2009

The static friction (stiction) of the molecularly thin films of an irregularly shaped molecule 1,3-dimethylbutyl octyl ether (DBOE) confined between mica surfaces was investigated using the surface forces apparatus. Stop-start experiments were carried out and the stiction spike was measured as a function of surface stopping (aging) time t and applied pressure P. The results show two relaxation processes, one on stopping and one on starting, where each process has a fast and a slow time constant. For stopping mode, there is no stiction spike when t is shorter than a characteristic nucleation time, τn (fast time constant). When t exceeds τn, stiction spike appears whose height increases logarithmically with t. With regard to starting, the relaxation behavior was evaluated by a double exponential fit of the slipping regime (force decay) of the spike and two time constants (τ1 and τ2) were obtained. The fast time constant on starting τ1 is almost equal to that on stopping τn. To the best of our knowledge, this is the first direct observation of the agreement of the time constant on stopping and that on starting, indicative of a reversible structural transition (solid-liquid transition) in the stop-start stiction dynamics. The two fast time constants exhibit exponential dependence on P, which implies a glasslike nature of the transition. Comparison with the stick-slip friction reveals that the solid-liquid transition involved in stiction and that in stick-slip dynamics is different for DBOE; first-order-like discontinuous transition is suggested for stick-slip friction. Origins of the different solid-liquid transition dynamics in stiction and in stick-slip friction are discussed by comparing with the dynamics of other confined liquid systems.
Chip-based microcavities coupled to nitrogen-vacancy centers in single crystal diamond
Authors: Barclay Paul E. , Fu Kai-Mei C. , Santori Charles , Beausoleil Raymond G.
Published: November 2009

Optical coupling of nitrogen-vacancy centers in single-crystal diamond to an on-chip microcavity is demonstrated. The microcavity is fabricated from a hybrid gallium phosphide and diamond material system and supports whispering gallery mode resonances with spectrometer resolution limited Q>25 000.
Magneto-optical detection of single flux quantum signals in superconducting quantum interference device
Authors: Murakami Hironaru , Kitamura Ryohei , Kawayama Iwao , Tonouchi Masayoshi
Published: November 2009

The properties of an YBa2Cu3O7−d superconducting quantum interference device (SQUID) have been evaluated magneto-optically and electrically. It was found that the operating characteristics of the SQUID observed by means of the magneto-optical (MO) method show a good consistency with those measured by the electrical method. Furthermore, we have succeeded in the MO detection of local magnetic signals corresponding to the single flux quantum pulses generated in the SQUID loop applied with an external pulsed magnetic field. These results indicate that the MO probe has the potential to be applied to an optical output interface for superconducting magnetic flux devices.
Local tuning of photonic crystal nanocavity modes by laser-assisted oxidation
Authors: Lee H. S. , Kiravittaya S. , Kumar S. , Plumhof J. D. , Balet L. , Li L. H. , Francardi M. , Gerardino A. , Fiore A. , Rastelli A. , Schmidt O. G.
Published: November 2009

The authors demonstrate a simple method to achieve local tuning of optical modes in GaAs photonic crystal nanocavities by continuous wave laser-assisted oxidation in air atmosphere. By irradiation with a focused laser beam at power levels of a few tens of milliwatts, photonic crystal nanocavity modes shift to shorter wavelengths by up to 2.5 nm. The mode shifts can be controlled either by varying the laser power or by iterating laser-assisted oxidation steps and are well explained by finite-element-method and finite-difference time-domain simulations. This method provides a simple route to achieve fine spectral tuning of individual nanocavities for photonic devices.
Experiments on peer-to-peer locking of magnetrons
Authors: Cruz E. J. , Hoff B. W. , Pengvanich P. , Lau Y. Y. , Gilgenbach R. M. , Luginsland J. W.
Published: November 2009

Experiments on peer-to-peer locking of 2 kW magnetrons are performed. These experiments verify the recently developed theory on the condition under which the two nonlinear oscillators may be locked to a common frequency. Dependent on the coupling, the frequency of oscillation when locking occurs does not necessarily lie between the free running frequencies of the two isolated, stand-alone magnetrons. Likewise, when the locking condition is violated, the beat frequency is not necessarily equal to the difference between these free running frequencies.