bluuebunny/crossref_metadata_2025 huggingface dataset:
Boron and nitrogen substitutional impurities inducing magnetic and half‐metallic behavior in zigzag silicon carbon nanoribbons
Authors: Lou Ping
Published: September 2011

Zigzag silicon carbon nanoribbons (ZSiC NRs) containing one substitutional nitrogen (N) or boron (B) atom in each super cell that includes four units are investigated by first‐principles calculations. It is found that the system where one of the edge Si atoms was substituted by a B atom presents ferromagnetic half‐metallic behavior, while the system where one of the edge C atoms was substituted by an N atom shows ferrimagnetic half‐metallic behavior. Moreover, in contrast to the pristine system, where the edge magnetism appears at both edges, the edge magnetism of the B‐doped system only appears at the C edge, while the edge magnetism of the N‐doped system only appears at the Si edge. These are because a B atom substituting one of the edge Si atoms destroys the local spin moment at the edge Si atoms, but an N atom substituting one of the edge C atoms destroys the local spin moment at the edge C atoms. When the size of the super cell increases to six units, the dilute doping case, the local spin moment at some edge atoms, where the substitution impurity resides at the edge, remains. This means that the dilute doping fails to completely destroy the local spin moment at the edge atoms, where the impurity resides at the edge. However, the half‐metallic band structure remains in the dilute doping case. Thus, a B atom substituting one of the edge Si atoms, as well as an N atom substituting one of the edge C atoms, induces a semiconductor–half‐metallic transition in the ZSiC NRs.
Electrochemical and XPS studies on corrosion behaviours of AISI 304 and AISI 316 stainless steels under plastic deformation in sulphuric acid solution
Authors: Lai W. Y. , Zhao W. Z. , Yin Z. F. , Zhang J.
Published: September 2011

The corrosion behaviours of austenitic stainless steels were investigated by electrochemical methods under plastic deformation with constant strain in the naturally aerated 0.5 M H2SO4 + 0.2 M KCl solution at room temperature. The work addresses the influence of plastic deformation and molybdenum element on the corrosion resistance of austenitic stainless steels in the test solution. Electrochemical impedance spectroscopy presents the decreasing charge transfer resistance (Rt) and polarization resistance (Rp) values with the immersion time for AISI 304 stainless steel under constant strain deformation, and the increasing Rt and Rp values with the immersion time for AISI 316 stainless steel. The analysis of the chemical composition of the corrosion products was carried out by XPS. Molybdenum addition in AISI 316 stainless steel affects significantly the corrosion resistance because of its high ability to form Mo (VI) and MoCl5 insoluble compounds in acid medium. Copyright © 2011 John Wiley & Sons, Ltd.
Natural dispersal or illegal pets? Limitations on assigning origin to road‐killed ocelots in the southwestern United States
Authors: Holbrook Joseph D. , DeYoung Randy W. , Tewes Michael E. , Young John H. , Mays Jody L. , Meyers Ed
Published: September 2011

The ocelot (Leopardus pardalis) is a spotted felid that is critically endangered in the United States (U.S.). During spring 2010, 2 ocelots were road‐killed in the southwestern U.S. far from known populations; an adult male near Palo Pinto, Texas, and a subadult male near Globe, Arizona. Necropsy results indicated that the Palo Pinto ocelot was likely a captive, whereas the Arizona ocelot was consistent with a wild individual. We used genetic data to determine the geographic origin of the ocelot lineages. A South American assignment would suggest human‐mediated transfer of ocelots, whereas an assignment to northern Mexico may indicate natural movements. We acquired reference‐sequence data and performed a phylogenetic analysis. Our results suggested that the Palo Pinto ocelot's lineage was from northern Mexico or southern Texas. The Arizona ocelot's lineage grouped with Mexico and Guatemala; however, sampling constraints prevented any explicit geographic assignments. Collecting additional genetic samples throughout Mexico is essential for future assignment analyses, and to determine whether illegal pet trafficking is occurring. These efforts would also provide necessary data to assist ocelot recovery in the U.S. © 2011 The Wildlife Society.
Preparation, Structural and Spectroscopic Characterization of Vanadium(IV) and Vanadium(V) Complexes with Dipicolinic Acid
Authors: Hakimi Mohammad , Kukovec Boris‐Marko , Rezvaninezhad Maryam , Schuh Esther , Mohr Fabian
Published: September 2011

The reaction of dipicolinic acid, dipicH2, with vanadyl sulfate in the mixture of ethanol and water led to the formation of[VO(dipic)(H2O)2]·C2H5OH (1) and [VO(dipic)(H2O)(OC2H5)] (2). Complex 1 was obtained first and complex 2 after prolonged standing of the mother liquor in air. Both complexes were characterized by elemental analyses, IR, Raman and UV/Vis spectroscopic analyses and their structures were determined by X‐ray diffraction. The vanadium(IV) ion in 1 and vanadium(V) ion in 2 are both coordinated by the O,N,O′‐tridentate dipicolinate ligand. The octahedral coordination of the vanadium(IV) atom is completed by two water molecules in trans position and by an oxo oxygen atom, whereas the vanadium(V) atom is additionally coordinated by an oxo oxygen atom and a water molecule in trans position and by an ethoxido oxygen atom. A co‐crystallized ethanol molecule is also present in the crystal structure of 1. Molecules of [VO(dipic)(H2O)2] and ethanol are linked into a 2D network by the O–H···O hydrogen bonds in the structure of 1. Molecules of 2 are assembled into a 3D structure by the O–H···O hydrogen bonds.
VLCAD enzyme activity determinations in newborns identified by screening: a valuable tool for risk assessment
Authors: Hoffmann Lars , Haussmann Ulrike , Mueller Martina , Spiekerkoetter Ute
Published: September 2011

Tandem mass spectrometry‐based newborn screening correctly identifies individuals with very long‐chain acyl‐CoA dehydrogenase deficiency (VLCADD). However, a great number of healthy individuals present with identical acylcarnitine profiles during catabolism in the first three days of life. We routinely perform an enzyme activity assay as confirmation analysis in newborns identified by screening. Whereas VLCAD residual activities of less than 10% are clearly diagnostic and indicate patients at risk of clinical disease, the clinical relevance of higher residual activities is unclear. In this study we assess the molecular basis in 34 individuals with residual activities of 10‐50%. We identify two pathogenic mutations in patients that result in residual activities as high as 22%, while individuals with residual activities of 25‐50% either present with a heterozygous or no mutation in the VLCAD gene. In addition, confirmed heterozygous parents present with residual activities as low as 32%.

In conclusion, we identify individuals with 2 pathogenic mutations and those with only one heterozygous mutation in the residual activity range of 20‐30%. Whereas heterozygosity is generally regarded as clinically irrelevant, identification of 2 VLCAD mutations leads to precautions in the management of the children. Based on our data we anticipate that individuals with a residual enzyme activity >20% present with a biochemical phenotype but likely remain asymptomatic throughout life. Studies in greater patient numbers are needed to correlate residual activities >10% with the genotype and the outcome.
Orthopaedic management of spina bifida—part II: Foot and ankle deformities
Authors: Swaroop Vineeta T. , Dias Luciano
Published: September 2011

Both congenital and acquired orthopaedic deformities are common in patients with spina bifida. Examples of congenital deformities, which are present at birth, include clubfoot and vertical talus. Acquired developmental deformities are related to the level of neurologic involvement and include calcaneus and cavovarus. Orthopaedic deformities may also result from postoperative tethered cord syndrome. The previously published Part I reviewed the overall orthopaedic care of a patient with spina bifida, with a focused review of hip, knee, and rotational deformities. This paper will cover foot and ankle deformities associated with spina bifida, including clubfoot, equinus, vertical talus, calcaneus and calcaneovalgus, ankle and hindfoot valgus, and cavovarus. In addition, this paper will address the issues surrounding skin breakdown in patients with spina bifida.
The Intergenerational Transmission of Churchgoing in England and Australia
Authors: Voas David , Storm Ingrid
Published: September 2011

The family is an important setting for the transmission of values and traditions, and parents have a significant influence on the religious involvement of their children. The family typically provides an initial religious identity and introduces children to religious beliefs, practices and a network of adherents. For both scholars and practitioners, the question of how religion does or does not come to be passed on in families is of crucial importance. In this study we use data from the 2001 International Congregational Life Survey to examine church attendance across three generations in England and Australia. In both England and Australia there is a strong tendency for couples to attend church together; they are making joint decisions and, when churchgoing is favored, encouraging each other in religious practice. The impact of two churchgoing parents on their children is considerably stronger than that of one alone. Our analysis shows that not only parental but also grandparental religious activity has a significant effect. While much of their influence simply results from the upbringing they gave their own children, a substantial proportion of it seems likely to be a direct, unmediated effect on grandchildren.
Effects of walnut consumption on cognitive performance in young adults
Authors: Pribis Peter , Bailey Rudolph N. , Russell Andrew A. , Kilsby Marcia A. , Hernandez Magaly , Craig Winston J. , Grajales Tevni , Shavlik David J. , Sabatè Joan
Published: September 2011

Walnuts contain a number of potentially neuroprotective compounds like vitamin E, folate, melatonin, several antioxidative polyphenols and significant amounts ofn-3 α-linolenic fatty acid. The present study sought to determine the effect of walnuts on verbal and non-verbal reasoning, memory and mood. A total of sixty-four college students were randomly assigned to two treatment sequences in a crossover fashion: walnuts–placebo or placebo–walnuts. Baseline data were collected for non-verbal reasoning, verbal reasoning, memory and mood states. Data were collected again after 8 weeks of intervention. After 6 weeks of washout, the intervention groups followed the diets in reverse order. Data were collected once more at the end of the 8-week intervention period. No significant increases were detected for mood, non-verbal reasoning or memory on the walnut-supplemented diet. However, inferential verbal reasoning increased significantly by 11·2 %, indicating a medium effect size (P = 0·009;d = 0·567). In young, healthy, normal adults, walnuts do not appear to improve memory, mood or non-verbal reasoning abilities. However, walnuts may have the ability to increase inferential reasoning.
The effect of food preparation on the bioavailability of carotenoids from carrots using intrinsic labelling
Authors: Ghavami Abdollah , Coward W. Andy , Bluck Les J. C.
Published: September 2011

A strategy to reduce the incidence of vitamin A deficiency is to improve precursor bioavailability from meals. Since vitamin A precursors are fat-soluble, we noted that carotenoids are more easily absorbed from food if prepared in such a way that the food matrix containing provitamin A (β-carotene) is sufficiently fat rich. To quantify this effect, we have developed a stable isotope methodology. By regular watering with2H-labelled water, we were able to produce several kg of intrinsically labelled carrots, with carotenoids labelled to 0·63 % excess2H. These were divided into 100 g portions and fed to a small group of healthy subjects both raw and stir-fried. To normalise for inter-individual variation in absorption and subsequent metabolism, small quantities of extrinsically13C-labelled β-carotene and2H-labelled retinol acetate were also incorporated into the meal. After ingestion of the carrots, blood lipids were monitored for a period of 3 d in order to determine the kinetics of β-carotene and retinol. From kinetic data, it was estimated that the bioavailability of carrot-derived β-carotene compared with pure β-carotene was about 11 % for raw carrots, but 75 % when the carrots were stir-fried. Conversely, there was a slight reduction in the bioconversion to retinol from β-carotene when the latter was derived from the stir-fried meal compared with that from raw carrots. When these two factors are combined, the yield of retinol from the carotene in carrots was found to be enhanced by a factor of 6·5 by stir-frying.
Intrusion history of the Portrush Sill, County Antrim, Northern Ireland: evidence for rapid emplacement and high-temperature contact metamorphism
Authors: LEDEVIN MORGANE , ARNDT NICHOLAS , COOPER MARK R. , EARLS GARTH , LYLE PAUL , AUBOURG CHARLES , LEWIN ERIC
Published: September 2011

The gabbroic Portrush Sill in Northern Ireland, part of the North Atlantic Igneous Province, intruded Lower Jurassic mudstones and siltstones about 55 Ma ago. We used petrologic observations and geochemical analyses to study how the sill interacted with the sedimentary rocks. Field relationships show that an Upper Sill and numerous associated Minor Intrusions were emplaced in the sedimentary host rocks before intrusion of the Main Sill, some 10 m above its upper contact. Geochemical analyses reveal two magma contamination processes: Nb and Ta anomalies, coupled with incompatible element enrichment, record contamination by deep crustal rocks, whereas Li, Pb and Ba anomalies reveal a superficial contamination through fluid circulation at the contact between magmatic and sedimentary rocks. Analysis of mineral assemblages and geochemical data from the contact aureole demonstrate uniform metamorphic conditions between the two main intrusions and an absence of a thermal gradient. The identification of pyrrhotite by magnetization analyses and of orthopyroxene by microprobe analyses indicates very high temperatures, up to 660°C. Thermal modelling explains these temperatures as the coupled effects of the Main Sill and the earlier intruded Upper Sill and Minor Intrusions. Even though the chemical composition of the Main Sill suggests another type of parental liquid, all three units were emplaced in a very short time, certainly less than five years.
The prevalence and fertility of hydatid cysts in buffaloes from Iran
Authors: Amin Pour A. , Hosseini S. H. , Shayan P.
Published: September 2011

Cystic echinococcosis caused by Echinococcus granulosus is considered to be an important parasitic infection in livestock. In the present study, which aimed to determine the epidemiology of hydatidosis in buffalo in Iran, slaughterhouses of West Azerbaijan (Urmia), East Azerbaijan (Tabriz), Ardabil (Ardabil), Gilan (Rasht and Hashtpar) and Khuzestan (Ahvaz) were inspected. Age, sex and infected organs were recorded separately, and the observed cysts were examined for fertility and viability. Our results showed that 344 (9%) of 3832 inspected buffaloes were infected with hydatid cysts. The maximum and minimum infection rates occurred in Khuzestan (9.9%) and Ardabil (8%) provinces, respectively. There was no significant difference in the rate of infection in all provinces. Of 344 infected buffaloes, the rate of fertility was 7.3% and the rate of viability in fertile cysts was 78.75%. Hydatid cysts were more prevalent in female compared with male buffaloes (P < 0.05). There was a positive correlation between the age and number of infected hosts in all provinces except East Azerbaijan. The prevalence of infection in lungs was significantly higher than that in the livers of buffaloes in the provinces studied (P < 0.001). In conclusion, the fertility of hydatid cysts in buffaloes was low, as previously demonstrated in cattle, and this animal may play a minor role in the epidemiology of hydatidosis in Iran.
Generalized Hausdorff dimensions of sets of real numbers with zero entropy expansion
Authors: MAUDUIT CHRISTIAN , MOREIRA CARLOS GUSTAVO
Published: September 2011

The complexity function of an infinite wordwon a finite alphabetAis the sequence counting, for each non-negative integern, the number of words of lengthnon the alphabetAthat are factors of the infinite wordw. Letfbe a given function with subexponential growth. The goal of this work is to estimate the generalized Hausdorff dimensions of the set of real numbers whoseq-adic expansion has a complexity function bounded byfand the set of real numbers whose continued fraction expansion is bounded byqand has a complexity function bounded byf.
Applications of (a,b)-continued fraction transformations
Authors: KATOK SVETLANA , UGARCOVICI ILIE
Published: September 2011

We describe a general method of arithmetic coding of geodesics on the modular surface based on the study of one-dimensional Gauss-like maps associated to a two-parameter family of continued fractions introduced in [Katok and Ugarcovici. Structure of attractors for (a,b)-continued fraction transformations.J. Modern Dynamics4(2010), 637–691]. The finite rectangular structure of the attractors of the natural extension maps and the corresponding ‘reduction theory’ play an essential role. In special cases, when an (a,b)-expansion admits a so-called ‘dual’, the coding sequences are obtained by juxtaposition of the boundary expansions of the fixed points, and the set of coding sequences is a countable sofic shift. We also prove that the natural extension maps are Bernoulli shifts and compute the density of the absolutely continuous invariant measure and the measure-theoretic entropy of the one-dimensional map.
NO CHILD LEFT BEHIND AND ITS EFFECTS ON LANGUAGE POLICY
Authors: Menken Kate
Published: September 2011

The most recent federal education policy in the United States, titled No Child Left Behind (NCLB), was passed into law in 2001. High-stakes testing is the core of NCLB, as tests are used to hold each school, district, and state accountable for student performance, therein affording the federal government greater control over the constitutionally decentralized national system of U.S. education. Because the tests being used are administered in English, English language learners (ELLs) typically fail to meet the law's annual progress requirements, resulting in serious consequences for the students and their schools. This article reviews research about the effects of NCLB on language policies in education. Empirical studies show that the law—which is at face value merely an educational policy—is in actuality a de facto language policy. After explaining the law's assessment mandates, this article provides analyses of the wording of NCLB from a language policy perspective. It also reviews studies about the limitations of the required tests as instruments to carry out the law's demands, and about the effects of the law on instruction and the educational experiences of ELLs.
Escherichia coliO157 infection on cattle farms: the formulation of the force of infection and its effect on control effectiveness
Authors: ZHANG X.-S.
Published: September 2011

The kernel of modelling transmission dynamics of infectious diseases lies in constructing the force of infection (FOI). Traditionally, it was based on mass-action law. In this paper, we show, based on survey data ofEscherichia coliO157 infection on Scottish cattle farms, that the actual form of FOI deviates greatly from mass-action law. Further, control effectiveness deviates qualitatively: the epidemic of mass-action FOI can be controlled with a control effort larger than the so-called herd immunity, while the epidemic inferred from the survey data ofE. coliO157 infection was shown to be difficult to control. This indicates that, at least forE. coliO157 infection on cattle farms, it is risky to rely on models of transmission dynamics that were based on mass-action law to design the optimal intervention programme for infectious diseases. This suggests the importance of collecting epidemic data and model selection from data-driven models to infer the most likely model of transmission dynamics.
Quality of Internet information related to the Mediterranean diet
Authors: Hirasawa Reiko , Saito Kazumi , Yachi Yoko , Ibe Yoko , Kodama Satoru , Asumi Mihoko , Horikawa Chika , Saito Aki , Heianza Yoriko , Kondo Kazuo , Shimano Hitoshi , Sone Hirohito
Published: September 2011

Objective

The present study aimed to evaluate the quality of Internet information on the Mediterranean diet and to determine the relationship between the quality of information and the website source.

Design

Website sources were categorized as institutional, pharmaceutical, non-pharmaceutical commercial, charitable, support and alternative medicine. Content quality was evaluated using the DISCERN rating instrument, the Health On the Net Foundation's (HON) code principles, andJournal of the American Medical Association(JAMA) benchmarks. Readability was graded by the Flesch Reading Ease score and Flesch–Kincaid Grade Level score.

Setting

The phrase ‘Mediterranean diet’ was entered as a search term into the six most commonly used English-language search engines.

Subjects

The first thirty websites forthcoming by each engine were examined.

Results

Of the 180 websites identified, thirty-two met our inclusion criteria. Distribution of the website sources was: institutional,n8 (25 %); non-pharmaceutical commercial,n12 (38 %); and support,n12 (38 %). As evaluated by the DISCERN, thirty-one of the thirty-two websites were rated as fair to very poor. Non-pharmaceutical commercial sites scored significantly lower than institutional and support sites (P= 0·002). The mean Flesch Reading Ease score and mean Flesch–Kincaid Grade Level were 55·9 (fairly difficult) and 7·2, respectively. The Flesch–Kincaid Grade Level score determines the difficulty of material by measuring the length of words and sentences and converting the results into a grade level ranging from 0 to 12 (US grade level).

Conclusions

Due to the poor quality of website information on the Mediterranean diet, patients or consumers who are interested in the Mediterranean diet should get advice from physicians or dietitians.
A multidisciplinary Earth science research program in China
Authors: Dong Shuwen , Li Tingdong , Gao Rui , Hou Hesheng , Li Yingkang , Zhang Shihong , Keller G. Randy , Liu Mian
Published: September 2011

Because China occupies a large and geologically complex region of central and eastern Asia, the country may hold the keys to resolving many basic problems in the Earth sciences, such as how continental collision with India produced China's interconnected array of large intraplate structures, and what links exist between these structures and natural resources. To learn more, the Chinese government has launched SinoProbe, a major research initiative focusing on multidisciplinary imaging of the three‐dimensional (3‐D) structure and composition of the Chinese continental lithosphere and its evolution through geologic history. This effort is also motivated by China's need for a comprehensive and systematic evaluation of its natural resources and a better understanding of potential geohazards. SinoProbe is funded by the Chinese Ministry of Finance, managed by the Chinese Ministry of Land and Resources, and organized by the Chinese Academy of Geological Sciences. More than 960 investigators and engineers are currently involved with the program, not counting international collaborators. Most of them are affiliated with the Chinese Academy of Geological Sciences, the Chinese Academy of Sciences, the Ministry of Education (i.e., universities), and the China Earthquake Administration. The initial phase of the program (2008–2012), with funding equivalent to about US$164 million, is testing the feasibility of new technologies in geophysical and geochemical exploration and deep continental drilling by focusing on a series of profiles (Figure 1).
Variability of Antarctic Bottom Water at 24.5°N in the Atlantic
Authors: Frajka‐Williams E. , Cunningham S. A. , Bryden H. , King B. A.
Published: September 2011

A recent hydrographic section at 24.5°N in the Atlantic and 6 months of observations from a moored array show that Antarctic Bottom Water (AABW), the densest and deepest water mass in the world oceans, has been warming. While Johnson et al. (2008) showed that northward AABW transport at 24.5°N has been declining from 1981 to 2004, suggesting that the lower cell of the overturning circulation could halt in the near future, estimates from the latest hydrographic section in 2010 indicate a partial recovery of northward AABW transport. From 6 months of temperature and salinity observations at a deep moored array at 24–26°N, we find that short‐term variability between April and November 2009 is of the same magnitude as the changes observed from hydrographic sections between 1981 and 2004. These observations highlight the possibility that transport changes estimated from hydrographic sections may be aliased by short‐term variability. The observed AABW transport variability affects present estimates of the upper meridional overturning circulation by ±0.4 Sv (1 Sv = 106 m3s−1).
Observations of low‐elevation ionospheric anomalies for ground‐based augmentation of GNSS
Authors: Lee Jiyun , Datta‐Barua Seebany , Zhang Godwin , Pullen Sam , Enge Per
Published: September 2011

Extreme ionospheric anomalies occurring during severe ionospheric activity can pose an integrity threat to users of Global Navigation Satellite System (GNSS) Ground Based Augmentation Systems (GBAS). While most very large spatial gradients in slant ionospheric delay were observed on high‐elevation satellites, several extreme gradients were also observed on satellites below 15 degrees elevation. This paper details the study of anomalous ionospheric spatial gradients for low‐elevation satellites observed from the 20 November 2003 geomagnetic storm in the Conterminous United States (CONUS). As viewed by a cluster of Continuously Operating Reference Stations (CORS) receivers in northern Ohio, SVN 26 came into view around 20:30 Universal Time (UT) on this day, rose to an elevation angle of about 15 degrees, and set around 22:00 UT. A spatial gradient of 360 mm/km was discovered at 21:20 UT between CORS stations GARF and WOOS, when SVN 26 was at 11 degrees elevation. Ionospheric delay measurements are vulnerable to semi‐codeless L2 tracking errors and data post‐processing errors, especially when satellites are at low elevation. This paper presents a series of methods to validate observed ionospheric anomaly events using station‐wide checks, satellite‐wide checks, and manual verification with single‐frequency measurements. Spatial gradients discovered at other station pairs and another low elevation satellite with a similar azimuth angle, SVN 29, support that the event of SVN 26 is an ionospheric anomaly as opposed to a receiver fault.
Band structure properties of novel BxGa1−xP alloys for silicon integration
Authors: Hossain Nadir , Hosea T. J. C. , Sweeney Stephen J. , Liebich Sven , Zimprich Martin , Volz Kerstin , Kunert Bernardette , Stolz Wolfgang
Published: September 2011

We have grown and investigated the band-structure properties of novel III-V alloys based upon BxGa1−xP. These layers are utilized as strain-compensating layers for the lattice-matched integration of novel direct bandgap Ga(NAsP) quantum well lasers on silicon. Experimental and theoretical studies reveal the dependence of the direct and indirect band gaps for strained BxGa1−xP layers grown on silicon as a function of Boron composition from which we derive the properties of free-standing BxGa1−xP. For Boron fractions up to 6%, we find that the bowing parameter for the lowest (indirect) band gap is − 6.2 ± 0.2 eV. High crystalline quality and promising optical material properties are demonstrated and applied to monolithically integrated Ga(NAsP)/(BGa)P multi-quantum well heterostructures on (001) silicon substrates. Our results show that novel (BGa)P layers are suitable for strain compensation purposes, which pave the way towards a commercial solution for the monolithic integration of long term stable laser diodes on silicon substrates.
Thermodynamics of twisted DNA with solvent interaction
Authors: Zoli Marco
Published: September 2011

The imaginary time path integral formalism is applied to a nonlinear Hamiltonian for a short fragment of heterogeneous DNA with a stabilizing solvent interaction term. Torsional effects are modeled by a twist angle between neighboring base pairs stacked along the molecule backbone. The base pair displacements are described by an ensemble of temperature dependent paths thus incorporating those fluctuational effects which shape the multisteps thermal denaturation. By summing over ∼107 − 108 base pair paths, a large number of double helix configurations is taken into account consistently with the physical requirements of the model potential. The partition function is computed as a function of the twist. It is found that the equilibrium twist angle, peculiar of B-DNA at room temperature, yields the stablest helicoidal geometry against thermal disruption of the base pair hydrogen bonds. This result is corroborated by the computation of thermodynamical properties such as fractions of open base pairs and specific heat.
The equivalence of the Lagrangian-averaged Navier-Stokes-α model and the rational large eddy simulation model in two dimensions
Authors: Nadiga Balasubramanya T. , Bouchet Freddy
Published: September 2011

In the large eddy simulation (LES) framework for modeling a turbulent flow, when the large scale velocity field is defined by low-pass filtering the full velocity field, a Taylor series expansion of the full velocity field in terms of the large scale velocity field leads (at the leading order) to the nonlinear gradient model for the subfilter stresses. Motivated by the fact that while the nonlinear gradient model shows excellent a priori agreement in resolved simulations, the use of this model by itself is problematic, we consider two models that are related, but better behaved. The rational LES model that uses a sub-diagonal Pade approximation instead of a Taylor series expansion, and the Lagrangian averaged Navier-Stokes-α model that uses a regularization approach to modeling turbulence. In this article, we show that these two latter models are identical in two dimensions.
On the probability distribution function of the velocity field and its derivative in multi-scale turbulence
Authors: Good Garrett H. , Warhaft Zellman
Published: September 2011

Using a combination of active and passive grids, we produce an inhomogeneous turbulent flow with strongly non-Gaussian velocity probability distribution (density) functions (pdfs). This new, multi-scale flow shares features with the turbulent jet in freestream turbulence, the near field of turbulence-generating grids, and atmospheric flows. In particular, we study unskewed velocity distributions with both super- and sub-Gaussian tails and demonstrate the linear dependence of the normalized odd and even moments of the distributions on the first and second spatial derivatives of the turbulence r.m.s. fields, respectively. We also note bimodal behavior of the pdfs. The experiments demonstrate a clear effect of the flow organization and the large-scale intermittency on the velocity derivative pdfs and the small scales of the turbulence. The work is motivated by the complex wind fields, and associated, intermittent high stresses, encountered by wind turbines. We also draw comparisons to recent studies of multi-scale turbulence produced by fractal grids.
High-field transport properties of graphene
Authors: Dong H. M. , Xu W. , Peeters F. M.
Published: September 2011

We present a theoretical investigation on the transport properties of graphene in the presence of high dc driving fields. Considering electron interactions with impurities and acoustic and optical phonons in graphene, we employ the momentum- and energy-balance equations derived from the Boltzmann equation to self-consistently evaluate the drift velocity and temperature of electrons in graphene in the linear and nonlinear response regimes. We find that the current-voltage relation exhibits distinctly nonlinear behavior, especially in the high electric field regime. Under the action of high-fields the large source-drain (sd) current density can be achieved and the current saturation in graphene is incomplete with increasing the sd voltage Vsd up to 3 V. Moreover, for high fields, Vsd>0.1 V, the heating of electrons in graphene occurs. It is shown that the sd current and electron temperature are sensitive to electron density and lattice temperature in the graphene device. This study is relevant to the application of graphene as high-field nano-electronic devices such as graphene field-effect transistors.
Generalized heat conduction laws based on thermomass theory and phonon hydrodynamics
Authors: Dong Yuan , Cao Bing-Yang , Guo Zeng-Yuan
Published: September 2011

The Fourier’s law of heat conduction is invalid in extreme conditions, such as the second sound in solids and anomalous heat conduction in nanosystems. The generalized heat conduction law with nonlinear and nonlocal effects is derived from both macroscopic thermomass theory and microscopic phonon Boltzmann method in this paper. The coincidence between thermomass theory and phonon hydrodynamics is also analyzed through their microscopic basis. The convective term in the momentum equation of the thermomass theory comes from the nonlinear terms of the distribution function, which is often neglected in previous phonon hydrodynamics derivations. The Chapman-Enskog expansion leads to the Laplacian term, which is similar to the derivation of Navier-Stokes equation in hydrodynamics and inspires the introduction of a Brinkman extension in the thermomass equation. This comparison reveals how the nonlinear effects could be described by generalized heat conduction laws.
Magneto-piezoresistance in elastomagnetic composites
Authors: Ausanio Giovanni , Hison Cornelia L. , Iannotti Vincenzo , Lanotte Luca , Lanotte Luciano
Published: September 2011

Ni microparticles were homogeneously dispersed into a silicone matrix preventing their direct contact even at volume fractions near the percolation threshold. In this condition, owing to the co-presence of elastomagnetic and piezoresistive effects, a moderate gradient of an external magnetizing field induces an electron conduction increment higher than 60% in Ni-silicone elastomagnetic composites. This demonstrates a peculiar kind of magnetoresistance mechanism that we define as “magneto-piezoresistance.” Theoretical predictions and validating experiments of this effect are reported. Owing to its innovative nature and potential improvements, the magneto-piezoresistance opens new perspectives for the elastomagnetic composites application in microdevices such as atomic force microscope tips and magnetic lecture heads.
Coaxial cable Bragg grating
Authors: Wei Tao , Wu Songping , Huang Jie , Xiao Hai , Fan Jun
Published: September 2011

This paper reports a coaxial cable Bragg grating (CCBG) fabricated by drilling holes into the cable at periodic distances along the axial direction. Resonances were observed at discrete frequencies in both transmission and reflection spectra. The analogy of the CCBG with a fiber Bragg grating is shown. The grating was tested for the potential application as a strain-sensing device.
An analytic algorithm for shape reconstruction from low-frequency moments
Authors: Charalambopoulos Antonios
Published: September 2011

In the present work, a novel method, concerning the solution of the inverse scattering problem, is developed and implemented, in the realm of low-frequency acoustics. The method is based on the suitable exploitation of the low-frequency moments, which are the structural pieces of the far-field pattern. The stimulus for the present method has been offered by a recent accomplishment permitting the extraction of the moments from the far-field pattern via a systematic, direct, and stable manner. The aim of the method is to reconstruct polynomial scatterers and to approximate general scatterers by polynomial surfaces. This is accomplished via the formulation of suitable objective functionals involving the unknown coefficients of the Cartesian representation of the sought polynomial surface along with the low-frequency moments. These functionals are constructed by forcing the target polynomial surface to comply with the moments extracted from real data. The minimization of these functionals provides the optimized coefficients of the polynomial manifold, while stability is inherent in the nature of the minimization process. The method has been implemented to the reconstruction of second and fourth order polynomial scatterers as well as to fitting of general scatterers by polynomial surfaces.
Parallel memristive filaments model applicable to bipolar and filamentary resistive switching
Authors: Liu Xinjun , Biju Kuyyadi P. , Lee Joonmyoung , Park Jubong , Kim Seonghyun , Park Sangsu , Shin Jungho , Sadaf Sharif Md. , Hwang Hyunsang
Published: September 2011

The concept of memristive filaments (MFs) is introduced, which is based on the memristors developed by the Hewlett–Packard group. The effects of key parameters on electrical properties are elucidated. The current–voltage features of bipolar and filamentary resistive switching are reproduced by using a parallel MF model with dynamic growth and rupture of multiple MFs. This model can be extended and adapted to most nanosized transition metal oxide memristors.
Optical properties of multi-layer type II InP/GaAs quantum dots studied by surface photovoltage spectroscopy
Authors: Ivanov Ts. , Donchev V. , Germanova K. , Gomes P. F. , Iikawa F. , Brasil M. J. S. P. , Cotta M. A.
Published: September 2011

We present a low-temperature (73 K) study of the optical properties of multi-layer type II InP/GaAs self-assembled quantum dots by means of surface photovoltage (SPV) spectroscopy, taking advantage of its high sensitivity and contactless nature. The samples contain 10 periods of InP quantum dot planes separated by 5 nm GaAs spacers. The SPV amplitude spectra reveal two major broad peaks, situated at low and high energies, respectively. These features are analyzed taking into account the type II character of the structure, the quantum coupling effects, the spectral behavior of the SPV phase, and the photoluminescence spectra. As a result they have been attributed to optical transitions in the quantum dots and the wetting layers, respectively. The main mechanism for carrier separation in the SPV generation process is clarified via the analysis of the SPV phase spectra. The influence of the substrate absorption on the SPV spectra is discussed in details.
Magnetic field influence on the transient photoresistivity of defect-induced magnetic ZnO films
Authors: Zapata C. , Khalid M. , Simonelli G. , Villafuerte M. , Heluani S. P. , Esquinazi P.
Published: September 2011

Magnetic field dependent photoresistivity was measured at 280 K in ZnO ferromagnetic films grown on r-plane Al2O3 under a N2 atmosphere. A correlation between the negative magneto photoresistivity and the existence of defect-induced magnetic order was found. The effect of magnetic field on the transient photoresistivity is to slow down the recombination process enhancing the photocarriers density. The experimental results demonstrate the possibility of tuning photocarriers life time using magnetic field in diluted magnetic semiconductors.
Spectral optimization of warm-white light-emitting diode lamp with both color rendering index (CRI) and special CRI of R9 above 90
Authors: He Guoxing , Xu Jing , Yan Huafeng
Published: September 2011

The optimal spectra of the warm-white LED (WWLED) lamp consisting of AlGaInP red LED and the p-W LED packaged by combining silicate green and orange phosphors with a InGaN blue LED die was obtained by nonlinear program for maximizing the luminous efficacy of radiation while both color rendering index (CRI) and special CRI of R9 for strong red above 90 at correlated color temeratures (CCTs) of 2700 K. The optimal peak wavelengths of red LED, blue LED die, silicate green and orange phosphors are 626 nm, 454 nm, 535 nm and 584 nm, respectively. Their optimal relative radation fluxs are 9.7%, 33.4 %, 26.1 %, 30.8 %, respectively. The real WWLED lamp with CCT of 2653 K, CRI of 90, R9 of 94 and R(9-12) of 88, as well as luminous efficacy (LE) of 80.2 lm/W have been realized. Furthermore, the WWLED lamp can realized CCT tunable warm-white-light with CRIs of 86 ∼ 93, R9s of 86 ∼ 95 and LEs of 78.2 ∼ 80.3 lm/W at CCTs of 2392 K to 3014 K by adjusting drive current of the red LED.
Allied, scientific and complementary health professionals: a new model for Australian allied health
Authors: Turnbull Catherine , Grimmer-Somers Karen , Kumar Saravana , May Esther , Law Deborah , Ashworth Elaine
Published: September 2011

There is no standard or agreed definition of ?allied
health? nationally or internationally. This paper
reviews existing definitions of allied health, and
considers aspects of allied health services and
service delivery in order to produce a new model
of allied health that will be flexible in a changing
health service delivery workforce. We propose a
comprehensive model of allied, scientific and
complementary (ASC) health professionals. This
model recognises tasks, training, organisation,
health sectors and professional regulation. It
incorporates traditional and new services which
are congruent with allied health foci, allegiances,
responsibilities and directions. Use of this model
will allow individual organisations to describe their
ASC health workforce, and plan for recruitment,
staff training and remuneration.
Discontinuous DP-coordination in German
Authors: Prinzhorn Martin , Schmitt Viola
Published: September 2011

In this paper, we introduce what we consider to be a new problem for syntactic analysis. We show that German allows for discontinuous coordination of DPs, where material that is not part of the coordinate structure may intervene between the DP-coordinates. We further argue that discontinuous coordination of DPs differs from standard DP-coordination in one important aspect: The coordinate structure as a whole is not accessible to material c-commanded by the first coordinate in overt syntax. This difference is a non-trivial problem for any analysis of discontinuous DP-coordination. Keywords: coordinate structures; discontinuous constituents; DP-coordination; German syntax; linear order
Outcome‐based education: a critique
Authors: Brady Laurie
Published: September 2011

In Australia, the National Curriculum framework contains a national position on each of eight learning areas, and a profile indicating outcomes that students have to achieve. Thus Australia's National Curriculum involves the implementation of outcome‐based education. This term has little currency in England and Wales, despite programmes of national testing, and there is a paucity of research in Australia because of the recentness of implementation. For this reason the bulk of the theoretical and empirical literature relates to the United States. This article examines the concept of outcome‐based education focusing on the various ways it is interpreted, and its claimed advantages and disadvantages. The author concludes that the adoption of a mastery learning model involving the teaching of structured hierarchical units with frequent testing is unlikely in Australia with its constructivist ethos and the lack of a strong behaviourist tradition.
A curriculum for food: places left at the school table?
Authors: Morrison Marlene
Published: September 2011

The paper examines recent developments in food‐focused education following the implementation of the 1988 Education Reform Act. Drawing on data from an ESRC‐funded project on Teaching and Learning about Food and Nutrition in Schools (1993‐4), the paper explores evidence which demonstrates a marginalized and fragmented curriculum for food, and considers its implications. The paper comprises two sections. The first focuses on literature and curriculum documentation available at the start of the research and examines the formal corpus of school knowledge about food. This informs the second section which draws on data collected during case‐studies of four English secondary and primary schools and on what the data tell us about the food curriculum and its implications for transmission in the case‐study schools. Specific examples highlight issues of diversity, ambiguity and contradiction in implementation. Conclusions emphasize the need for greater curriculum coherence in policy and practice and for a reassessment of the framing and interpretation of food knowledge and skills. In the absence of systematic evaluations, schools continue to replicate rather than challenge the contradictions in understandings about food use which are documented features of the adult population in general.
‘How does your teacher help you to make your work better?’ Children's understanding of formative assessment
Authors: Tunstall Pat , Gipps Caroline
Published: September 2011

This paper on children's perceptions of formative assessment summarizes one important part of the research carried out by our project on teacher feedback which was funded by the Economic and Social Research Council1 over the two years 1994‐5. Our major research questions were:

• What sort of feedback do teachers give children?

• How do children interpret, understand and act on this feedback?

The research involved both teachers and children directly in discussion of feedback and assessment through interviews. Observations and recording in classrooms were also carried out. The findings have shown that the role of feedback is central in learning, and that systematic study in this area can make an important contribution to the conceptual framework of the relationship between teaching, assessment and learning. Our discussions with children provided us with a range of insights into how they perceived feedback, what they felt about it and how they used it. The typology itself is presented in full in Tunstall and Gipps (1996). In this paper, we concentrate on what formative assessment means to young children.