bluuebunny/crossref_metadata_2025 huggingface dataset:
Consumer preferences for micronutrient strategies in China. A comparison between folic acid supplementation and folate biofortification
Authors: De Steur Hans , Feng Shuyi , Xiaoping Shi , Gellynck Xavier
Published: March 2013

Objective

Despite public health efforts, folate deficiency is still largely prevalent in poor, rural populations and continues to cause a large burden of disease. The present paper determines and compares consumer preferences for two folate strategies: folic acid supplementationv.folate biofortification, i.e. the enhancement of the folate content in staple crops.

Design

Experimental auctions with non-repeated information rounds are applied to rice in order to obtain willingness-to-pay for folate products. Thereby, GM or non-GM folate-biofortified rice (FBR) is auctioned together with rice that is supplemented with free folic acid pills (FAR).

Setting

Shanxi Province (China) as a high-risk region of folate deficiency.

Subjects

One hundred and twenty-six women of childbearing age, divided into a school (n60) and market sample (n66).

Results

Despite differences according to the targeted sample, a general preference for folate biofortification is observed, regardless of the applied breeding technology. Premiums vary between 33·9 % (GM FBR), 36·5 % (non-GM FBR) and 19·0 % (FAR). Zero bidding behaviour as well as the product choice question, respectively, support and validate these findings. The targeted sample, the timing of the auction, the intention to consume GM food and the responsibility for rice purchases are considered key determinants of product choice. A novel ex-post negative valuation procedure shows low consistency in zero bidding.

Conclusions

While the low attractiveness of FAR provides an additional argument for the limited effectiveness of past folic acid supplementation programmes, the positive reactions towards GM FBR further support its potential as a possible complementary micronutrient intervention.
The relationship between exchange rates and international trade: a literature review
Authors: AUBOIN MARC , RUTA MICHELE
Published: March 2013

This paper surveys a wide body of economic literature on the relationship between exchange rates and trade. Specifically, two main issues are investigated: the impact of exchange rate volatility and of currency misalignments on international trade flows. On average, exchange rate volatility has a negative (even if not large) impact on trade. The extent of this effect depends on a number of factors, including the existence of hedging instruments, the structure of production (e.g. the prevalence of small firms), and the degree of economic integration across countries. The second issue involves exchange rate misalignments, which are predicted to have short-run effects in models with price rigidities. However, the exact impact depends on a number of features, such as the pricing strategy of firms engaging in international trade and the importance of global production networks. Trade effects of currency misalignments are predicted to disappear in the long-run, unless an economy is characterized by other relevant distortions. Empirical results broadly confirm these theoretical predictions.
Three Shortcomings of the Social Investment Perspective
Authors: Cantillon Bea , Van Lancker Wim
Published: March 2013

In this article we critically assess the social investment perspective that has become the dominant paradigm in European social policymaking. We identify and discuss some of its shortcomings that may hamper social progress for all. In doing so, we focus on three pillars central to the idea of social investment: social inclusion through work, individual responsibility and human capital investment. We find that the social investment perspective has some serious flaws when it comes to the social protection of vulnerable groups. This is strongly related to the continuing relevance of social class in explaining and remedying social inequalities. We conclude that investment cannot be the only rationale for welfare state intervention and that protecting people should remain equally high on the policy agenda.
Climate change and crop wild relatives: can species track their suitable environment, and what do they lose in the process?
Authors: Cobben Marleen M. P. , van Treuren Rob , van Hintum Theo J. L.
Published: March 2013

Crop wild relatives are an increasingly important source of plant genetic resources for plant breeders. Several studies have estimated the effects of climate change on the distribution of crop wild relatives, using species distribution models. In this approach, two important aspects, i.e. species' dispersal capacity and founder effects, are currently not taken into account. Neglecting these aspects can lead to an underestimation of the climate change-induced threat to the size of the species range and the conservation of range-wide levels of genetic diversity. This paper presents two recommendations for the interpretation of the results obtained with these models. The integration of process-based simulation models and statistical species distribution models will facilitate the inclusion of dispersal processes and founder effects in future assessments of the resilience of plant genetic resources under climate change.
Epistemic Institutions and Epistemic Cooperation in International Environmental Governance
Authors: Meyer Timothy
Published: March 2013

Under what conditions should epistemic institutions (institutions that provide policy-relevant scientific advice) be integrated into international legal institutions – for example, the Conference of the Parties to the United Nations Framework Convention on Climate Change? Following work in law and economics on the theory of the firm, this article argues that where states will not implement environmental policies absent a collective decision to do so, greater hierarchical control of epistemic institutions by legal institutions may be necessary to ensure the credibility and availability of a usable scientific record. Hierarchy creates credibility because it allows all states necessary for cooperation in the legal institution to oversee the production of the scientific record that provides the basis for international legal rules. Hierarchy thus enhances the effectiveness of international law as a coordination tool, even at the expense of the autonomy of the scientific process. By contrast, where collective action is not necessary because states will unilaterally regulate an environmental problem once scientific uncertainty has been reduced, epistemic and legal institutions should be fragmented to ensure the unbiased production and dissemination of scientific information. In such situations, the credibility of the scientific record is demonstrated by decentralized adoption of science-based regulation.
City Networks as Alternative Geographies of Southeast Asia
Authors: Bunnell Tim
Published: March 2013

Over the last two decades, research on world cities and global cities has unsettled the nation-state as the default unit of analysis in many disciplines in Anglophone social science. Rather than seeing the world as comprised of a mosaic of national political and social units, alternative geographies of networks connecting cities and urban regions have risen to prominence. In this paper, I consider the implications of such alternative mappings for Southeast Asia, bringing urban studies and area studies into critical conversation with each other. Geographies of urban networks extending across national borders challenge the ingrained methodological nationalism of conventional area studies, not least in Southeast Asia. However, to what extent do framings of trans-national urban connections among Southeast Asian or Asian cities mean that methodological nationalism has simply been up-scaled to methodological regionalism? In the first of the two main sections of the paper, I look in detail at the network spatialities brought into view by global and world cities scholars and consider their implications for regional urban systems frameworks. Flows of people, money and ideas extending from cities in Southeast Asia to cities beyond that region, and even trans-continentally, arguably imply that areal framings melt into network geographies which are global in scope. In the second section of the paper, I consider three types of regional formations that have been identified in research on globalization: the global triad regions, region states, and inter-Asia flows of capital; models and people which I examine do not map onto conventional cartographies of Southeast Asia. Together, these two sections of the paper serve as a reminder that in future research regions need to be specified empirically rather than assumed to exist asa prioriframings for research, and that the geographies of ‘actually existing’ regionalizing processes are often very different from area studies mappings of the world.
From Rural to Urban: A Geography of Boundary Crossing in Southeast Asia
Authors: Rigg Jonathan
Published: March 2013

Migration, mobility, and movement are the inter-linked processes which provide the empirical scaffold for this paper. The paper uses this empirical framing to reflect on a series of methodological, conceptual, and theoretical challenges for scholars of Southeast Asia. Mobility and associated geographical (spatial) boundary crossings have raised questions about the analytical units employed in research; the unsettling of these analytical units has challenged whether conceptual categories still have explanatory purchase; and the fracturing of conceptual categories has implications for the theoretical frameworks that scholars have traditionally deployed. Drawing on field research undertaken in Laos, Thailand, and Vietnam the paper argues that evolving mobilities in the region, particularly in rural areas, require a degree of explanatory ‘catch-up’ on the part of scholars as we try to keep pace with the rate of change in the countryside. Instead of focusing on households in space, we should be trying to map out the networked relations that link lives and individuals across national and transnational space. The paper further argues that we should focus our attention on local-level dynamics associated with societal change, settlement dynamism and sustainability, population turbulence, and evolving cultural preferences which operate partly independently of the rural development project, thus highlighting the shifting web of mutual dependencies and interdependencies that shape lives and living patterns.
MOF@activated carbon: a new material for adsorption of aldicarb in biological systems
Authors: de Oliveira Carlos Alberto Fernandes , da Silva Fausthon Fred , Jimenez George Chaves , da S. Neto José Ferreira , de Souza Daniela Maria Bastos , de Souza Ivone Antônia , Júnior Severino Alves
Published: March 2013

MOF@activated carbon: synthesis and characterization of novel composite materials with applications as adsorbents for aldicarb detoxification in biological systems.
Special Considerations When Working With the Pediatric Vocal Performer
Authors: Blakeslee Sarah D. M.
Published: March 2013

Providing care to a performer with vocal injury requires an understanding of the physiology of the singing voice and appreciation for the complexities of the life of a performer. However, when the performer who presents to the clinic is a child or teenager, there are additional challenges, and providing appropriate care requires a special understanding of the changes that take place during vocal development across childhood and adolescence. This includes the physical changes that occur in the respiratory, phonatory, and resonatory systems; the effects of these changes on the singing voice especially in regards to puberty; and additional challenges ones faces when working with a performer who may have minimal training and whose instrument is continuing to develop. A thorough evaluation is necessary before recommending voice therapy. Voice therapy with pediatric vocal performers is similar to voice therapy with adults, but may have a larger focus on education regarding normal anatomy and physiology of the vocal mechanism, vocal hygiene, vocal warm-ups, and basic singing technique.
Definitive evidence for linked resonances in surface-enhanced Raman scattering: Excitation profile of Cu phthalocyanine
Authors: . Londero Pablo S , Leona Marco , Lombardi John R.
Published: March 2013

We have characterized the surface-enhanced Raman spectroscopy (SERS) spectrum of copper phthalocyanine as a function of excitation wavelength in the 435–635 nm region using a tunable excitation Raman system. We show that the Raman excitation spectrum within the surface plasmon resonance is dominated by totally symmetric modes in the blue and non-totally symmetric modes in the red. The findings are compared to our recent theoretical work on the nature of SERS enhancement. The experimental results are interpreted to be a consequence of vibronically coupled intensity borrowing by charge transfer resonances from allowed molecular transitions, enhancing non-totally symmetric modes.
Formation of graphene nano-particle by means of pulsed discharge to ethanol
Authors: Matsushima Masahiro , Noda Mikio , Yoshida Takuya , Kato Hiroomi , Kalita Golap , Kizuki Takashi , Uchida Hideo , Umeno Masayoshi , Wakita Koichi
Published: March 2013

Nano-graphene particles (NGPs) were deposited by a pulsed discharge (PD) to ethanol in Ar gas atmosphere of about 600 Torr. The frequency (f) of the PD was changed from 1 to 5 kHz at constant duty ratio of 20%. Evaluations of the NGPs were performed with scanning electron microscope, high resolution transmission electron microscope, and Raman spectra. When f was changed from 1 to 5 kHz, domain size of the NGPs was decreased from 34 to 19 nm. The number of the graphene layers (GLs) was decreased from about 20 to 4, though the number of GLs was scattered from 24 to 2. These results show that the domain size and the number of the GLs can be controlled with f of the PD.
Strain effects in epitaxial Mn2O3 thin film grown on MgO(100)
Authors: Duc Dung Dang , Van Thiet Duong , Anh Tuan Duong , Cho Sunglae
Published: March 2013

We report on the epitaxial growth and magnetic properties of Mn2O3 thin films grown on MgO(001) substrate by molecular beam epitaxy. We observed the reduction in binding energy of Mn valence states, the increase in satellite separation up to 12.7 eV, and the smaller band gap of 3.32 eV. In addition, the antiferromagnetic ordering below 90 K in bulk changed to ferrimagnetic up to 175 K. The results were possibly to be explained by a lattice mismatch strain on Mn2O3 film on MgO(001) substrate.
A first-principles study of magnetism of lithium fluorosulphate LiFeSO4F
Authors: Tsevelmaa Tumurbaatar , Odkhuu Dorj , Kwon Oryong , Cheol Hong Soon
Published: March 2013

Magnetism of tavorite and triplite LixFeSO4F (x = 0, 1/2, and 1) has been studied using the first-principles density-functional theory. It was found that an antiferromagnetic ordering is more stable compared to a ferromagnetic state and the energy difference between two magnetic states is reduced when the lithium is intercalated, being consistent with a recent experimental observation of lowering Neel temperature from 100 K of FeSO4F to 25 K of LiFeSO4F. Furthermore, the magnetic moment of 3.8 μB/Fe for FeSO4F was found to be oriented along the [010], whereas that (4.3 μB/Fe) of LiFeSO4F along the [001]. And the magnetic moment and magneto-crystalline anisotropy were found to be insensitive upon different atomic structures, which imply that the lithium intercalation affects the spin orientation of Fe rather than the interplay between lattice and magnetism suggested by an experiment.
Label-free detection of anticancer drug paclitaxel in living cells by confocal Raman microscopy
Authors: Salehi H. , Derely L. , Vegh A.-G. , Durand J.-C. , Gergely C. , Larroque C. , Fauroux M.-A. , Cuisinier F. J. G.
Published: March 2013

Confocal Raman microscopy, a non-invasive, label-free, and high spatial resolution imaging technique is employed to trace the anticancer drug paclitaxel in living Michigan Cancer Foundation-7 (MCF-7) cells. The Raman images were treated by K-mean cluster analysis to detect the drug in cells. Distribution of paclitaxel in cells is verified by calculating the correlation coefficient between the reference spectrum of the drug and the whole Raman image spectra. A time dependent gradual diffusion of paclitaxel all over the cell is observed suggesting a complementary picture of the pharmaceutical action of this drug based on rapid binding of free tubulin to crystallized paclitaxel.
Large refractive index in BiFeO3-BiCoO3 epitaxial films
Authors: Shima Hiromi , Nishida Ken , Yamamoto Takashi , Tadokoro Toshiyasu , Tsutsumi Koichi , Suzuki Michio , Naganuma Hiroshi
Published: March 2013

Rhombohedral (R-) and tetragonal (T-) Bi(Fe,Co)O3 (BFCO) films were epitaxially grown on the SrTiO3 (100) substrates, and the optical properties of the BFCO films were evaluated by spectroscopic ellipsometry. It was revealed that the refractive indexes of R- and T-BFCO epitaxial films were 2.93 and 2.86 at wavelength of 600 nm, and 2.65 and 2.59 at 1550 nm, respectively, which are comparable to the pure BiFeO3. The refractive index of the R-BFCO film was totally larger than that of the T-BFCO film; it might be caused by structural strain and local symmetry breaking. It was confirmed that the extinction coefficients of both films were almost zero at wavelengths larger than 600 nm. In addition, the optical band gaps of the R- and T-BFCO films were estimated to be 2.78 and 2.75 eV, respectively. It can expect that the BFCO film has a possibility to use optical-magnetic field sensor working at room temperature.
Expansion of the energy of the ground state of the Gross–Pitaevskii equation in the Thomas–Fermi limit
Authors: Gallo Clément
Published: March 2013

From the asymptotic expansion of the ground state of the Gross–Pitaevskii equation in the Thomas–Fermi limit given by Gallo and Pelinovsky [“On the Thomas-Fermi ground state in a harmonic potential,” Asymptot. Anal. 73(1–2), 53–96 (2011)]10.3233/ASY-2011-1034, we infer an asymptotic expansion of the kinetic, potential, and total energy of the ground state. In particular, we give a rigorous proof of the expansion of the kinetic energy calculated by Dalfovo, Pitaevskii, and Stringari [“Order parameter at the boundary of a trapped Bose gas,” Phys. Rev. A 54, 4213–4217 (1996)]10.1103/PhysRevA.54.4213 in the case where the space dimension is 3. Moreover, we calculate one more term in this expansion, and we generalize the result to space dimensions 1 and 2.
Tendency to occupy a statistically dominant spatial state of the flow as a driving force for turbulent transition
Authors: Chekmarev Sergei F.
Published: March 2013

The transition from laminar to turbulent fluid motion occurring at large Reynolds numbers is generally associated with the instability of the laminar flow. On the other hand, since the turbulent flow characteristically appears in the form of spatially localized structures (e.g., eddies) filling the flow field, a tendency to occupy such a structured state of the flow cannot be ruled out as a driving force for turbulent transition. To examine this possibility, we propose a simple analytical model that treats the flow as a collection of localized spatial structures, each of which consists of elementary cells in which the behavior of the particles (atoms or molecules) is uncorrelated. This allows us to introduce the Reynolds number, associating it with the ratio between the total phase volume for the system and that for the elementary cell. Using the principle of maximum entropy to calculate the most probable size distribution of the localized structures, we show that as the Reynolds number increases, the elementary cells group into the localized structures, which successfully explains turbulent transition and some other general properties of turbulent flows. An important feature of the present model is that a bridge between the spatial-statistical description of the flow and hydrodynamic equations is established. We show that the basic assumptions underlying the model, i.e., that the particles are indistinguishable and elementary volumes of phase space exist in which the state of the particles is uncertain, are involved in the derivation of the Navier-Stokes equation. Taking into account that the model captures essential features of turbulent flows, this suggests that the driving force for the turbulent transition is basically the same as in the present model, i.e., the tendency of the system to occupy a statistically dominant state plays a key role. The instability of the flow at high Reynolds numbers can then be a mechanism to initiate structural rearrangement of the flow to find this state.
Energy band alignment of atomic layer deposited HfO2 oxide film on epitaxial (100)Ge, (110)Ge, and (111)Ge layers
Authors: Hudait Mantu K. , Zhu Yan
Published: March 2013

Crystallographically oriented epitaxial Ge layers were grown on (100), (110), and (111)A GaAs substrates by in situ growth process using two separate molecular beam epitaxy chambers. The band alignment properties of atomic layer hafnium oxide (HfO2) film deposited on crystallographically oriented epitaxial Ge were investigated using x-ray photoelectron spectroscopy (XPS). Valence band offset, ΔEv values of HfO2 relative to (100)Ge, (110)Ge, and (111)Ge orientations were 2.8 eV, 2.28 eV, and 2.5 eV, respectively. Using XPS data, variation in valence band offset, ΔEV(100)Ge>ΔEV(111)Ge>ΔEV(110)Ge, was obtained related to Ge orientation. Also, the conduction band offset, ΔEc relation, ΔEc(110)Ge>ΔEc(111)Ge>ΔEc(100)Ge related to Ge orientations was obtained using the measured bandgap of HfO2 on each orientation and with the Ge bandgap of 0.67 eV. These band offset parameters for carrier confinement would offer an important guidance to design Ge-based p- and n-channel metal-oxide field-effect transistor for low-power application.
Sheath formation criterion in magnetized electronegative plasmas with thermal ions
Authors: Hatami M. M. , Shokri B.
Published: March 2013

Taking into account the effect of collisions and positive ion temperatures, the sheath formation criterion is investigated in a weakly magnetized electronegative plasma consisting of electrons, negative and positive ions by using the hydrodynamics equations. It is assumed that the electron and negative ion density distributions are the Boltzmann distribution with two different temperatures. Also, it is assumed that the velocity of positive ions at the sheath edge is not normal to the wall (oblique entrance). Our results show that a sheath region will be formed when the initial velocity of positive ions or the ion Mach number M lies in a specific interval with particular upper and lower limits. Also, it is shown that the presence of the magnetic field affects both of these limits. Moreover, as an practical application, the density distribution of charged particles in the sheath region is studied for an allowable value of M, and it is seen that monotonically reduction of the positive ion density distribution leading to the sheath formation occurs only when M lies between two above mentioned limits.
Possible quantum critical behaviour in the (Cr84Re16)100−yVy alloy system
Authors: Jacobs B. S. , Prinsloo A. R. E. , Sheppard C. J. , Strydom A. M.
Published: March 2013

Possible quantum critical behaviour in the (Cr84Re16)100−yVy alloy system, with 0 ≤ y < 14, was investigated using electrical resistivity (ρ), Seebeck coefficient (S), magnetic susceptibility (χ), Hall coefficient (RH), and specific heat (Cp) measurements as a function of temperature (T). Characteristics typically associated with a quantum critical point (QCP) can be observed in the low temperature behaviour of ρ(y), RH(y), χ(y), and γ(y); where γ is the Sommerfeld coefficient determined from least square fits to the low temperature specific heat measurements. Present results provide evidence of the existence of a putative QCP at a critical concentration of yc ≈ 10.5 for the (Cr84Re16)100−yVy alloy system.
Scalable fabrication of graphene devices through photolithography
Authors: Shi Runbo , Xu Huilong , Chen Bingyan , Zhang Zhiyong , Peng Lian-Mao
Published: March 2013

Scalable fabrication of high quality graphene devices is highly desired and important for the practical applications of graphene material. Graphene devices are massively fabricated on SiO2/Si substrate through an efficient process, which combines large scaled growth of monolayer graphene on Pt foil, modified bubbling transfer and photolithography-based device fabrication. These graphene devices present yield up to 86% (70 out of 81), field-effect mobility around 2500 cm2 V−1 S−1 and Dirac point voltage near to 0 V, as well as a narrow performance metrics distribution. In addition, as-fabricated graphene Hall elements through this process exhibit high current sensitivity typically up to 1200 V/AT.
Vibrational, elastic, and structural properties of cubic silicon carbide under pressure up to 75 GPa: Implication for a primary pressure scale
Authors: Zhuravlev K. K. , Goncharov Alexander F. , Tkachev S. N. , Dera P. , Prakapenka V. B.
Published: March 2013

We present results of concomitant measurements of synchrotron x-ray diffraction (XRD), Brillouin, and Raman spectroscopy on the single crystal samples of cubic silicon carbide (3C-SiC) under quasi-hydrostatic pressures up to 65 GPa, as well as x-ray diffraction and Raman spectroscopy up to 75 GPa. We determined the equation of state of 3C-SiC and pressure dependencies of the zone-center phonon, elastic tensor, and mode Gruneisen parameters. Cubic SiC lattice was found to be stable up to 75 GPa, but there is a tendency for destabilization above 40 GPa, based on softening of a transverse sound velocity. By applying the concomitant density and elasticity measurements, we determined the pressure on the SiC sample without referring to any other pressure scale thus establishing a new primary pressure scale with a 2%–4% precision up to 65 GPa. We proposed corrections to the existing ruby and neon pressure scales, and also calibrated cubic SiC as a pressure marker for the x-ray diffraction and Raman experiments.
Dielectric response and origin in antiferromagnetic/ferroelectric (1 − x)BiFeO3-(x)BaTiO3 ceramics
Authors: Tu C.-S. , Chien R. R. , Wang T.-H. , Anthoninappen J. , Peng Y.-T.
Published: March 2013

Dielectric permittivity (ε) and conductivity (σ) have been measured in (1 − x)BiFeO3-(x)BaTiO3 (BFO-xBT) multiferroic ceramics for x = 0.0, 0.05, and 0.10 as functions of temperature and frequency. A one-dimensional across-barrier model with intrinsic barriers B every lattice constant a and extrinsic barriers B + Δ every distance d is introduced to describe the dielectric response and conductivity. The across-barrier hopping is responsible for the high-temperature conductivity and dielectric relaxation in the lower temperature region. Good qualitative fits of dielectric permittivity and conductivity are obtained as functions of temperature and frequency. BaTiO3 substitution can enhance the intrinsic barrier and reduce the hopping conductivity.
A search for field-induced ordering in the optimally doped Ba(Fe,Co)2As2 superconductor
Authors: Quinn Katherine , Ryan D. H. , Canfield P. C. , Bud'ko S. L. , Cadogan J. M.
Published: March 2013

A 57Fe Mössbauer search for field-induced magnetic order in optimally doped Ba(Fe1−xCox)2As2 in fields of up to 6 T showed no changes that could be attributed to field-induced order. We also observed no difference between the normal (30 K) and superconducting states (5 K). Any field-induced order is certainly less than 1% of the order present in the parent BaFe2As2.
Optical design for improving optical properties of top-emitting organic light emitting diodes
Authors: Zhang Mingxiao , Chen Zhijian , Xiao Lixin , Qu Bo , Gong Qihuang
Published: March 2013

We present a simple and accurate optical model for simulation of the optical properties of top-emitting organic light emitting diodes (OLEDs). Based on the model, we investigated the optical properties of top-emitting OLEDs and optimized the structure of a blue top-emitting OLED based on 4,4′-bis(2,2′-diphenylvinyl)-1,1′-biphenyl. The device optimization process focused on matching the optical properties of each functional layer. The out-coupling efficiency of device with optimized structure can be enhanced by 80%; in addition, the color purity of blue emission is improved. Experimental results show excellent agreement with the simulation results.
Effects of valence-band mixing and strain on thermoelectric properties of p-type quantum wells
Authors: Tseng Yen-Chun , Kuo David M.-T. , Chang Yia-Chung
Published: March 2013

Thermoelectric properties of p-type quantum wells (QWs) with flat subbands are investigated theoretically. The effects due to valence-band mixing and strain in QWs are considered in the calculation of electrical conductivity (σ), Seebeck coefficient (S), thermal conductivity, and figure of merit (ZT). It is found that the maximum ZT of QWs can be enhanced under strain. Such an enhancement of ZT results from the fact that the enhancement of S2 is stronger than the reduction of σ. The maximum values of ZT at room temperature can reach 0.55, 0.7, and 2.2 for GaAs, InAs, and InSb QWs with well width of 5 nm. For comparison, the ZT values of p-type silicon (Si) and germanium (Ge) QWs are also calculated. The optimal ZT values of Si and Ge QWs at room temperature can reach 0.21 and 0.3, respectively.
Enhancement of ferromagnetism by Cr doping in Ni-Mn-Cr-Sb Heusler alloys
Authors: Khan Mahmud , Dubenko Igor , Stadler Shane , Jung J. , Stoyko S. S. , Mar Arthur , Quetz Abdiel , Samanta Tapas , Ali Naushad , Chow K. H.
Published: March 2013

A series of Mn rich Ni50Mn37−xCrxSb13 Heusler alloys have been investigated by dc magnetization and electrical resistivity measurements. Due to the weakening of the Ni-Mn hybridization, the martensitic transition shifts to lower temperatures with increasing Cr concentration, while the saturation magnetization at 5 K increases. The magnetoresistance and exchange bias properties are dramatically suppressed with increasing Cr concentration. The observed behaviors suggest that substitution of Cr for Mn in Ni50Mn37−xCrxSb13 Heusler alloys not only destabilizes the martensitic phase but also enhances ferromagnetism in the system. The possible mechanisms responsible for the observed behavior are discussed.
Ideal hydrodynamic scaling relations for a stagnated imploding spherical plasma liner formed by an array of merging plasma jets
Authors: Cassibry J. T. , Stanic M. , Hsu S. C.
Published: March 2013

This work presents scaling relations for the peak thermal pressure and stagnation time (over which peak pressure is sustained) for an imploding spherical plasma liner formed by an array of merging plasma jets. Results were derived from three-dimensional (3D) ideal hydrodynamic simulation results obtained using the smoothed particle hydrodynamics code SPHC. The 3D results were compared to equivalent one-dimensional (1D) simulation results. It is found that peak thermal pressure scales linearly with the number of jets and initial jet density and Mach number, quadratically with initial jet radius and velocity, and inversely with the initial jet length and the square of the chamber wall radius. The stagnation time scales approximately as the initial jet length divided by the initial jet velocity. Differences between the 3D and 1D results are attributed to the inclusion of thermal transport, ionization, and perfect symmetry in the 1D simulations. A subset of the results reported here formed the initial design basis for the Plasma Liner Experiment [S. C. Hsu et al., Phys. Plasmas 19, 123514 (2012)].
Magnetization reversal and spintronics of Ni/Graphene/Co induced by doped graphene
Authors: Kim Dongyoo , Hashmi Arqum , Hwang Chanyong , Hong Jisang
Published: March 2013

We have investigated the magnetization reversal induced by carrier doped graphene (Be, B, N, O, or Cl doping) in Ni/Graphene/Co. In undoped case, the magnetic layers have an antiferromagnetic (AFM) coupling and this is still preserved from Be to O doping. We find magnetization reversal from AFM to ferromagnetic interaction induced by Cl doped graphene. In addition, the Ni and the Co layers show the opposite spin asymmetry near the Fermi level and this implies that each layer will generate completely different in-plane spin current in the same direction if an external electric field is applied.
The study of in situ scanning tunnelling microscope characterization on GaN thin film grown by plasma assisted molecular beam epitaxy
Authors: Yang R. , Krzyzewski T. , Jones T.
Published: March 2013

The epitaxial growth of GaN by Plasma Assisted Molecular Beam Epitaxy was investigated by Scanning Tunnelling Microscope (STM). The GaN film was grown on initial GaN (0001) and monitored by in situ Reflection High Energy Electron Diffraction and STM during the growth. The STM characterization was carried out on different sub-films with increased thickness. The growth of GaN was achieved in 3D mode, and the hexagonal edge of GaN layers and growth gradient were observed. The final GaN was of Ga polarity and kept as (0001) orientation, without excess Ga adlayers or droplets formed on the surface.
Modification of organosilicate glasses low-k films under extreme and vacuum ultraviolet radiation
Authors: Rakhimova T. V. , Rakhimov A. T. , Mankelevich Yu. A. , Lopaev D. V. , Kovalev A. S. , Vasil'eva A. N. , Proshina O. V. , Braginsky O. V. , Zyryanov S. M. , Kurchikov K. , Novikova N. N. , Baklanov M. R.
Published: March 2013

Degradation of chemical composition of porous low-k films under extreme and various vacuum ultraviolet emissions is studied using specially developed sources. It is shown that the most significant damage is induced by Xe line emission (147 nm) in comparison with Ar (106 nm), He (58 nm), and Sn (13.5 nm) emissions. No direct damage was detected for 193 nm emission. Photoabsorption cross-sections and photodissociation quantum yields were derived for four films under study. 147 nm photons penetrate deeply into low-k films due to smaller photoabsorption cross-section and still have sufficient energy to excite Si-O-Si matrix and break Si-CH3 bonds.
Carrier localization and in-situ annealing effect on quaternary Ga1−xInxAsySb1−y/GaAs quantum wells grown by Sb pre-deposition
Authors: Thoma Jiri , Liang Baolai , Lewis Liam , Hegarty Stephen P. , Huyet Guillaume , Huffaker Diana L.
Published: March 2013

Using temperature-dependent photoluminescence spectroscopy, we have investigated and compared intrinsic InGaAs, intrinsic GaInAsSb, and p-i-n junction GaInAsSb quantum wells (QWs) embedded in GaAs barriers. Strong carrier localization inside the intrinsic GaInAsSb/GaAs QW has been observed together with its decrease inside the p-i-n sample. This is attributed to the effect of an in-situ annealing during the top p-doped AlGaAs layer growth at an elevated temperature of 580 °C, leading to Sb-atom diffusion and even atomic redistribution. High-resolution X-ray diffraction measurements and the decrease of both maximum localization energy and full delocalization temperature in the p-i-n QW sample further corroborated this conclusion.
Self-assembled perovskite-spinel heterostructure on a highly distorted substrate
Authors: Zhu Y. M. , Ke D. , Yu R. , Hsieh Y. H. , Liu H. J. , Liu P. P. , Chu Y. H. , Zhan Q.
Published: March 2013

The pattern configuration and interface structure in epitaxial BiFeO3-CoFe2O4 heterostructures grown on (010)pc NdGaO3 substrates have been investigated systematically by transmission electron microscopy and chemical analysis. The crystal orientation of CoFe2O4 variants was tuned to [111]CFO, while BiFeO3 kept [010]pc matching the substrate. Triangular prism-shaped CoFe2O4 embedded in the BiFeO3 matrix grew as an equilibrium island mode with {111}CFO as its surfaces and interfaces. Two types of BiFeO3-CoFe2O4 orientation relationships were determined as (001)[010]BFO//(0-22)[111]CFO and (101)[010]BFO//(−220)[111]CFO. The results reveal that the dominant factors controlling the growth orientation of the present vertical heterostructures are surface energy anisotropy and atomic structure continuity.
Role of excited state photoionization in the 852.1 nm Cs laser pumped by Cs-Ar photoassociation
Authors: Hewitt J. D. , Houlahan T. J. , Gallagher J. E. , Carroll D. L. , Palla A. D. , Verdeyen J. T. , Perram G. P. , Eden J. G.
Published: March 2013

Photoionization of Cs (6p 2P3/2) atoms during the operation of a Cs D2 line (852.1 nm: 6p 2P3/2→6s 2S1/2) laser, pumped by free→free transitions of thermal Cs-Ar ground state pairs, has been investigated experimentally and computationally. Photoexcitation of Cs vapor/Ar mixtures through the blue satellite of the D2 transition (peaking at 836.7 nm) selectively populates the 2P3/2 upper laser level by the dissociation of the CsAr excited complex. Comparison of laser output energy data, for instantaneous pump powers up to 3 MW, with the predictions of a numerical model sets an upper bound of 8 × 10−26 cm4 W−1 on the Cs (6p 2P3/2) two photon ionization cross-section at 836.7 nm which corresponds to a single photon cross-section of 2.4 × 10−19 cm2 for a peak pump intensity of 3 MW cm−2.
Simulation of chip-size electrocaloric refrigerator with high cooling-power density
Authors: Gu Haiming , Craven Brent , Qian Xiaoshi , Li Xinyu , Cheng Ailan , Zhang Q. M.
Published: March 2013

The large electrocaloric effect that found in ferroelectric polymers creates unique opportunity for developing high performance chip scale solid state refrigerator. This letter presents a finite volume simulation study and shows that by employing solid state regenerators and the micro-heat pumping mechanism used in the thermoacoustic cooling, a compact Electrocaloric Oscillatory Refrigeration (ECOR) device can be realized. The simulation results demonstrate that a 1 cm-long ECOR device can provide 9 W/cm3 volumetric cooling power density at 20 K temperature span. By tuning the device parameters in the model, the ECOR can reach more than 50% of the Carnot efficiency.
Understanding of cluster size deviation by measuring the dimensions of cluster jet from conical nozzles
Authors: Chen Guanglong , Geng Xiaotao , Xu Hongxia , Mi Yiming , Zhang Xiuli , Wang Lili , Kim Dong Eon
Published: March 2013

This work aims to understand the cluster size deviation from the prediction by an existing scaling law for conical nozzles. The dimensions of cluster jet at different heights above a nozzle along the direction of gas flow are measured. This study indicates that the dimension of cluster jet is underestimated in the existing scaling law and this under-estimation leads to the over-estimation of the equivalent diameter of conical nozzle. Thus the underestimation of the dimension of cluster jet may be one of possible factors responsible for the cluster size deviation (the degree of the deviation depends on details of cluster jet).
Comparative larval development of three amphidromous Rhinogobius species, making reference to their habitat preferences and migration biology
Authors: Kondo Masashi , Maeda Ken , Hirashima Kentarou , Tachihara Katsunori
Published: March 2013

Eggs and larvae of three amphidromous species of Rhinogobius goby (Rhinogobius brunneus, Rhinogobius sp. MO and Rhinogobius sp. CB) from Okinawa Island, Japan, were reared under uniform conditions to describe and compare their larval development. Although the larval morphologies of the three species were very similar, some differences were observed in the timing of ontogenetic events among them. R. brunneus had the largest yolk and saved it for a longer period of time, whereas Rhinogobius sp. MO had the smallest yolk, which was exhausted earlier. The period until yolk exhaustion is thought to restrict the distance that migrating larvae can drift, which determines the specific adult distribution. Each of these two amphidromous species are close relatives of different fluvial resident species. Evolution of the fluvial residents could be explained by different scenarios based on the larval traits of R. brunneus and Rhinogobius sp. MO. Rhinogobius sp. CB hatched at a smaller size and grew slower than the other two species. No fluvial species have derived from Rhinogobius sp. CB. One possible explanation is that the smaller and slower-growing larvae of Rhinogobius sp. CB find it more difficult to remain within streams.
Biophysical status of remnant freshwater floodplain lagoons in the Great Barrier Reef catchment: a challenge for assessment and monitoring
Authors: Pearson R. G. , Godfrey P. C. , Arthington A. H. , Wallace J. , Karim F. , Ellison M.
Published: March 2013

We investigated the biophysical environment, invertebrate fauna and ecosystem health of lagoons on the Tully–Murray floodplain in the Queensland Wet Tropics bioregion. These wetlands are biologically rich but have declined in area and condition with agricultural development and are poorly protected, despite being located between two World Heritage areas. Lagoons varied in size, habitats and water quality, with increasing signatures of agriculture (e.g. elevated nutrient concentrations) from the upper to lower floodplain. Zooplankton were abundant, but not diverse, and correlated variously with environmental variables, so were not useful in assessing lagoon condition. Benthic macroinvertebrates were abundant and diverse and correlated strongly with riparian condition, habitats, water quality and degree of agriculture in the catchment, but gradients in assemblage structure were not strong because the flow regime, with multiple annual floods, maintains higher water quality than in some tropical systems. The absence of pristine reference lagoons and the limited availability of replicate sites hamper the development of monitoring systems. Nevertheless, we show that appropriate sampling, analysis and knowledge of comparable systems allow inferences to be drawn regarding ecological condition. This is important because environmental managers need best available and timely advice whatever the opportunities for rigorous study design.
Status of the Sydney rock oyster in a disease-afflicted estuary: persistence of wild populations despite severe impacts on cultured counterparts
Authors: Wilkie Emma M. , Bishop Melanie J. , O'Connor Wayne A. , McPherson Ross G.
Published: March 2013

Marine diseases represent a significant threat to wild organisms and the ecosystem services they support, yet studies often consider only disease impacts to aquaculture. In eastern Australia, the Sydney rock oyster (Saccostrea glomerata) aquaculture industry is increasingly affected by outbreaks of QX disease caused by parasitic Marteilia sydneyi. The present study considered impacts of M. sydneyi infection on the structure of wild-oyster populations that are dominated by S. glomerata, but that may also include the non-native Pacific oyster, Crassostrea gigas. In the Hawkesbury River Estuary, where cultured S. glomerata has experienced up to 98% QX-induced mortality, we found that disease prevalence was comparatively low among wild S. glomerata, peaking at 14%, and annual infections did not cause seasonal patterns of mortality. Furthermore, C. gigas, a competitor of S. glomerata that is not susceptible to QX disease, was not consistently more abundant at sites with than without the parasite. Overall, our results indicated that relative to cultured counterparts, wild S. glomerata in the Hawkesbury River Estuary is minimally affected by QX disease. Nevertheless, our study showed that diseases of aquaculture stocks have the capacity to infect wild populations, and that longer-term assessment of wild populations at risk is essential.
Charred wood remaining after a wildfire as a reservoir of macro- and micronutrients in a Mediterranean pine forest
Authors: Marañón-Jiménez Sara , Castro Jorge , Fernández-Ondoño Emilia , Zamora Regino
Published: March 2013

Large amounts of logs and coarse woody debris remain in the ecosystem after wildfires. However, the relevance of the nutrient reservoir contained in the remaining post-fire woody debris for the ecosystem nutrient reserves is rarely considered. In this paper, we determine the carbon and nutrient concentrations in the partially charred wood after a wildfire along an altitudinal gradient and assess the relative magnitude of the nutrient reservoir in the wood in relation to those existing in the first 10-cm soil layer. Soils were poorly developed and nutrients limiting for the vegetation requirements. Charred woody material still contained a relatively high concentration of nutrients compared to those reported for unburnt pine wood, and in general, this decreased with altitude. Partially charred wood represented a considerable pool of nutrients, due to both the relatively high concentrations and to the great amount of biomass still present after the fire. Potential contributions of the charred wood were particularly relevant for N and micronutrients Na, Mn, Fe, Zn and Cu, as wood contained 2–9 times more nutrients than the soil. Post-fire woody debris constitutes therefore a valuable natural element as a potential source of nutrients, which would be lost from ecosystems in cases where it is removed.
Mechanisms of cell competition: Themes and variations
Authors: Levayer Romain , Moreno Eduardo
Published: March 2013

Cell competition is the short-range elimination of slow-dividing cells through apoptosis when confronted with a faster growing population. It is based on the comparison of relative cell fitness between neighboring cells and is a striking example of tissue adaptability that could play a central role in developmental error correction and cancer progression in both Drosophila melanogaster and mammals. Cell competition has led to the discovery of multiple pathways that affect cell fitness and drive cell elimination. The diversity of these pathways could reflect unrelated phenomena, yet recent evidence suggests some common wiring and the existence of a bona fide fitness comparison pathway.
A novel single-cell screening platform reveals proteome plasticity during yeast stress responses
Authors: Breker Michal , Gymrek Melissa , Schuldiner Maya
Published: March 2013

Uncovering the mechanisms underlying robust responses of cells to stress is crucial for our understanding of cellular physiology. Indeed, vast amounts of data have been collected on transcriptional responses in Saccharomyces cerevisiae. However, only a handful of pioneering studies describe the dynamics of proteins in response to external stimuli, despite the fact that regulation of protein levels and localization is an essential part of such responses. Here we characterized unprecedented proteome plasticity by systematically tracking the localization and abundance of 5,330 yeast proteins at single-cell resolution under three different stress conditions (DTT, H2O2, and nitrogen starvation) using the GFP-tagged yeast library. We uncovered a unique “fingerprint” of changes for each stress and elucidated a new response arsenal for adapting to radical environments. These include bet-hedging strategies, organelle rearrangement, and redistribution of protein localizations. All data are available for download through our online database, LOQATE (localization and quantitation atlas of yeast proteome).