bluuebunny/crossref_metadata_2025 huggingface dataset:
Food sharing and social cognition
Authors: Legg Edward William , Ostojić Ljerka , Clayton Nicola Susan
Published: December 2014

Many non‐human animals share food with each other, with kin, mates, and other unrelated individuals. When individuals share food with others they lose a valuable resource. Thus, traditionally much research has investigated how this behavior can be an evolutionarily stable strategy. Only recently has food‐sharing behavior been exploited to investigate non‐human cognition. Certain evolutionarily stable strategies that have been proposed as accounts for food‐sharing behaviors, such as reciprocity and interchange, may rely on complex cognitive abilities. In these cases, individuals may calculate the benefit they may receive from sharing with the recipient. In some species, sharing of food can facilitate the recipients' rate and extent of learning. This form of teaching may be cognitively complex if the donor takes into account the level of the recipient's abilities. In addition, an animal's food‐sharing behavior, which in itself may be based on a simple cognitive mechanism, could be used as a tool to investigate the extent to which the individual may be capable of complex cognitive abilities, for example, mental‐state attribution. These three areas of research, reciprocity, teaching, and mental‐state attribution, illustrate how food‐sharing behavior can be used as a valuable natural behavior to investigate cognition in non‐human animals. WIREs Cogn Sci 2015, 6:119–129. doi: 10.1002/wcs.1329

This article is categorized under:

Cognitive Biology > Evolutionary Roots of Cognition
Genetische Beratung bei Pränataldiagnostik
Authors: Schindelhauer-Deutscher H. Joachim , Henn Wolfram
Published: December 2014

Vor und nach jeder Pränataldiagnostik muss nach § 15 Abs. 3 des Gendiagnostikgesetzes verpflichtend eine genetische Beratung erfolgen, mit der die Schwangere in die Lage versetzt werden soll, eigenverantwortlich über die Inanspruchnahme der Untersuchung zu entscheiden und deren Ergebnisse für sich zu bewerten. Die in diesem Kommunikationsprozess zu vermittelnden Inhalte umfassen über medizinisch-genetische Fakten hinaus auch psychosoziale und ethische Aspekte, was die Einbindung nichtärztlicher Professionen nahelegen kann. Die Etablierung der nichtinvasiven Pränataldiagnostik hat erhebliche Auswirkungen auf Nutzen-Risiko-Abwägungen und damit auch auf die genetische Beratung. Im ergebnisoffenen Prozess der genetischen Beratung muss die Entscheidungsautonomie der Ratsuchenden respektiert, aber auch eigenen Wertvorstellungen der Berater Raum gegeben werden.
Spatial sorting of African Immigrants in the French Public Housing Market
Authors: Schmutz Benoît
Published: December 2014

This paper documents the existence of sorting patterns based on region of origin in the French public housing market (HLM). We provide evidence that first-generation African immigrants who benefit from the program tend to live in poorer neighborhoods than their French-born counterparts, once controlled for the broader geographical area of residence. This differential is comparable in magnitude to the one observed in the private rental market, even though the pricing of a public rental is almost uncorrelated with its location characteristics. Whereas we cannot rule out the possibility that this sorting partly reflects the specificity of African immigrants’ housing demand, we mitigate this concern by using information on the HLM offers that were previously rejected by the households and on the households’ declared level of satisfaction regarding their current neighborhood. Given that about half of African immigrants live in HLM (against one sixth of the non-immigrant population), this finding has possibly strong consequences on African immigrants’ segregation and welfare in France.
MicroRNA‐206 regulates surfactant secretion by targeting VAMP‐2
Authors: Zhang Honghao , Guo Yujie , Mishra Amarjit , Gou Deming , Chintagari Narendranath Reddy , Liu Lin
Published: December 2014

Lung surfactant secretion is a highly regulated process. Our previous studies have shown that VAMP‐2 is essential for surfactant secretion. In the present study we investigated the role of miR‐206 in surfactant secretion through VAMP‐2. VAMP‐2 was confirmed to be a target of miR‐206 by 3′‐untranslational region (3′‐UTR) luciferase assay. Mutations in the predicated miR‐206 binding sites reduced the binding of miR‐206 to the 3′‐UTR of VAMP‐2. miR‐206 decreased the expression of VAMP‐2 protein and decreased the lung surfactant secretion in alveolar type II cells. In conclusion, miR‐206 regulates lung surfactant secretion by limiting the availability of VAMP‐2 protein.
Changing serum levels of quantitative hepatitis B surface antigen and hepatitis B virus DNA in hepatitis B virus surface antigen carriers: A follow‐up study of an elderly cohort
Authors: Kuo Yuan‐Hung , Chang Kuo‐Ching , Wang Jing‐Houng , Tsai Pei‐Shan , Hung Shu‐Feng , Hung Chao‐Hung , Lu Sheng‐Nan
Published: December 2014

This study was to elucidate longitudinally quantitative changes of hepatitis B virus (HBV) surface antigen (HBsAg) and HBV DNA in elder HBsAg carriers in a community. Among 1002 residents screened for HBsAg in 2005, 405 responded to this follow‐up study in 2010. Fifty‐nine (14.6%) were HBsAg carriers in 2005; HBsAg quantification and HBV DNA were measured. HBsAg quantification (cutoff 1600 IU/mL) and HBV DNA (cutoff 2000 IU/mL) were combined to stratify the participants between two screens. A total of 30 men and 29 women with a mean age of 63.9 ± 7.9 years were enrolled. Quantitative levels of HBsAg and HBV DNA were significantly correlated in 2005 (r = 0.509, p < 0.001) and 2010 (r = 0.777, p < 0.001). Concentrations of HBsAg (IU/mL) significantly decreased from 2.2 ± 1.0 log in 2005 to 1.7 ± 1.5 log in 2010 (p < 0.001). The level of HBsAg was decreased in 48 (81.4%) individuals and HBsAg was undetectable in eight (13.6%). The annual incidence of HBsAg clearance was 2.7%. These 59 HBsAg carriers in 2005 were divided into four groups: low HBsAg low HBV DNA (n = 32), high HBsAg low HBV DNA (n = 5), low HBsAg high HBV DNA (n = 12) and high HBsAg high HBV DNA (n = 10). All 32 individuals in the low HBsAg low HBV DNA group were still in that group in 2010, whereas only two of the high HBsAg high HBV DNA group became inactive. As with a younger cohort in hospital, HBsAg quantification was still well correlated with HBV DNA in elderly HBsAg carriers in the community. Lower levels of both HBsAg and HBV DNA might represent an inactive HBV infection.
EXPERIENCE, AGENCY, AND PERSONAL IDENTITY
Authors: Schechtman Marya
Published: December 2014

Psychologically based accounts of personal identity over time start
from a view of persons as experiencing subjects. Derek Parfit argues that
if such an account is to justify the importance we attach to identity it
will need to provide a deep unity of consciousness throughout the life of
a person, and no such unity is possible. In response, many philosophers
have switched to a view of persons as essentially agents, arguing that the
importance of identity depends upon agential unity rather than unity of
consciousness. While this shift contributes significantly to the
discussion, it does not offer a fully satisfying alternative. Unity of
consciousness still seems required if identity is to be as important as we
think it is. Views of identity based on agential unity do, however, point
to a new understanding of unity of consciousness which meets Parfit's
challenge, yielding an integrated view of identity which sees persons as
both subjects and agents.
The Harms of Enhancement and the Conclusive Reasons View
Authors: DOUGLAS THOMAS
Published: December 2014

Many critics of bioenhancement go to considerable lengths to establish the existence of reasons against pursuing bioenhancements but do little to establish the absence of reasons in favor. This suggests that they accept what Allen Buchanan has called the conclusive reasons view (CRV). According to this view, our reasons against bioenhancement are obviously decisive, so there is no need to balance them against countervailing reasons. Buchanan criticizes the CRV by showing that the reasons most commonly adduced against bioenhancement are not decisive, or, at least, not obviously so.

In this article, I suggest that both Buchanan and the authors to whom he is responding underestimate the strength of the case for the CRV. There are, I argue, harm-based reasons against bioenhancement that provide stronger support to the CRV than the reasons that have most often been adduced by critics of enhancement. However, I then argue that even these harm-based reasons are not obviously decisive. Thus, I ultimately agree with Buchanan about the falsity of the CRV, though I disagree with him about the reasons for its falsity.
Doctors and Dr. Seuss
Authors: CARLIN NATHAN
Published: December 2014

In 2012, Dartmouth College renamed its medical school, founded in 1797, the Audrey and Theodor Geisel School of Medicine. Using the renaming of the medical school of Dartmouth College as a foil, I offer in this article a vision of what it might mean to align Theodor Geisel, better known as Dr. Seuss, with doctors by examining Geisel’s You’re Only Old Once! A Book for Obsolete Children. In this article, I derive four critiques of modern medicine from the book and offer four strategies as to how these critiques could be explored in medical education. If You’re Only Old Once! is read as a pathography, I argue that it can be used as a resource for medical education.
New growth modes of molybdenum oxide layered 1D structures using alternative catalysts: transverse mode vs. axial mode
Authors: Sheng Tao , Cao Baobao , Zhang Yong , Zhang Haitao
Published: December 2014

Both transverse and axial growth modes were discovered in the CVD synthesis of molybdenum oxide (MoO3) 1D structures using alkali metal based catalysts. A modified vapor–solid–solid (VSS) mechanism was proposed.
Synergistic effects of nonmetal co-doping with sulfur in anatase TiO2: a DFT + U study
Authors: Liu Qing-Lu , Zhao Zong-Yan , Liu Qing-Ju
Published: December 2014

S + NM co-doping could induce a stronger local electric field and eliminate the deep impurity energy bands of S mono-doped TiO2.
Physical and chemical tuning of two-dimensional transition metal dichalcogenides
Authors: Wang Haotian , Yuan Hongtao , Sae Hong Seung , Li Yanbin , Cui Yi
Published: December 2014

This review summaries the tunable properties of two-dimensional transition metal dichalcogenides through a variety of tuning methods.
Confocal and fluorescence lifetime imaging sheds light on the fate of a pyrene-tagged carbon monoxide-releasing Fischer carbene chromium complex
Authors: Arrowsmith Rory L. , Atkin Anthony J. , Botchway Stanley W. , Fairlamb Ian J. S. , Lynam Jason M. , Moir James W. B. , Pascu Sofia I. , Ward Jonathan S. , Zhang Wei-Qiang
Published: December 2014

The synthesis of a new pyrene-containing Fischer carbene complex is described.
Transition metal complex assisted Csp3–F bond formation
Authors: Lin Xiaoxi , Weng Zhiqiang
Published: December 2014

This Perspective mainly focuses on the most recent advances in transition-metal-complex-assisted synthesis of alkyl fluorides.
Pumpless microfluidic platform for drug testing on human skin equivalents
Authors: Abaci Hasan Erbil , Gledhill Karl , Guo Zongyou , Christiano Angela M. , Shuler Michael L.
Published: December 2014

Advances in bio-mimetic in vitro human skin models increase the efficiency of drug screening studies.
Metal-Amplified Density Assays, (MADAs), including a Density-Linked Immunosorbent Assay (DeLISA)
Authors: Subramaniam Anand Bala , Gonidec Mathieu , Shapiro Nathan D. , Kresse Kayleigh M. , Whitesides George M.
Published: December 2014

This paper reports a method of conducting quantitative and/or multiplexed assays, including immunoassays, by measuring metal-amplified changes in the density of protein-adsorbed beads using Magnetic Levitation (MagLev).
Carbonyl migration from phosphorus to the metal in binuclear phosphaketenyl metal carbonyl complexes to give bridging diphosphido complexes
Authors: Lü Wenjun , Wang Chaoyang , Luo Qiong , Li Qian-shu , Xie Yaoming , King R. Bruce , Schaefer III Henry F.
Published: December 2014

Carbonyl groups from bridging phosphaketenyl ligands in Mn2(CO)8(μ-PCO)2 are predicted to migrate from phosphorus to manganese upon decarbonylation, giving the diphosphido Mn2(CO)n+2(μ-P2) derivatives.
Layer speciation and electronic structure investigation of freestanding hexagonal boron nitride nanosheets
Authors: Wang Jian , Wang Zhiqiang , Cho Hyunjin , Kim Myung Jong , Sham T. K. , Sun Xuhui
Published: December 2014

Layer speciation, spatially-resolved XANES spectroscopy and polarization dependence of single and multilayered hBN nanosheets have been investigated by STXM.
Cyclopeptides containing the DEKS motif as conformationally restricted collagen telopeptide analogues: synthesis and conformational analysis
Authors: Wodtke Robert , Ruiz-Gómez Gloria , Kuchar Manuela , Pisabarro M. Teresa , Novotná Pavlina , Urbanová Marie , Steinbach Jörg , Pietzsch Jens , Löser Reik
Published: December 2014

The conformational stabilisation of the DEKS motif at the α1(I) collagenN-telopeptide within a cyclic hexapeptide together with its conformational analysis is described. This sequence is critical for lysyl oxidase-mediated collagen crosslinking, a process which is deregulated during tumour progression.
Amphiphilic polyether-based block copolymers as crosslinkable ligands for Au-nanoparticles
Authors: Hörenz Christoph , Rudolph Tobias , Barthel Markus J. , Günther Ulrike , Schacher Felix H.
Published: December 2014

We report on the synthesis of thiol-terminated, polyether-based block copolymers featuring a crosslinkable block and their use as ligands for Au-nanoparticles in organic solvents.
Synthesis of hyperbranched polymers and their applications in analytical chemistry
Authors: Sun Fengxia , Luo Xiaoling , Kang Lichao , Peng Xiayu , Lu Chunxia
Published: December 2014

This review focuses primarily on the recent developments in the synthesis of hyperbranched polymers and their application in analytical chemistry.
Cobalt aluminate nanoparticles supported on MIL-101 structure: catalytic performance investigation
Authors: Granadeiro Carlos M. , Karmaoui Mohamed , Correia Eva , Julião Diana , Amaral Vitor S. , Silva Nuno J. O. , Cunha-Silva Luís , Balula Salete S.
Published: December 2014

Novel heterogeneous catalysts composed by CoAl2O4 nanoparticles supported on MIL-101(Cr) framework exhibiting remarkable catalytic performance for thioanisole oxidation under sustainable conditions.
Temperature-switched controlled release nanosystems based on molecular recognition and polymer phase transition
Authors: Lv Shao-Nan , Cheng Chang-Jing , Song Ya-Ya , Zhao Zhi-Gang
Published: December 2014

Novel temperature-switched controlled release nanosystems based on molecular recognition of β-CD and thermosensitivity of PNIPAM phase transition of is developed.
Truxene: a promising scaffold for future materials
Authors: Goubard Fabrice , Dumur Frédéric
Published: December 2014

Truxene (10,15-dihydro-5H-diindeno[1,2-a;1′,2′-c]fluorene), which is a heptacyclic polyarene structure, has attracted a great deal of interest due to its exceptional solubility, high thermal stability and ease with which it may be modified.
SERS quantitative analysis of trace HSA with a Coomassie brilliant blue G-250 molecular probe in nanogold sol substrate
Authors: Liang Aihui , Lu Zujun , Liu Qingye , Zhang Xinghui , Wen Guiqing , Jiang Zhiliang
Published: December 2014

A SERS quantitative analysis method was developed for the detection of trace HSA with a Coomassie brilliant blue G-250 probe in nanogold sol substrate.
One-pot, three component tandem reaction of 2-aminopyridines, acetophenones and aldehydes: synthesis of 3-aroylimidazo[1,2-a]pyridines
Authors: Kaswan Pinku , Pericherla Kasiviswanadharaju , Saini Hitesh Kumar , Kumar Anil
Published: December 2014

A facile synthesis of 3-aroylimidazo[1,2-a]pyridine derivatives has been achieved via a copper(ii) chloride catalyzed one-pot, three-component tandem reaction of acetophenones, arylaldehydes and 2-aminopyridines.
Silver(i) ions modulate the stability of DNA duplexes containing cytosine, methylcytosine and hydroxymethylcytosine at different salt concentrations
Authors: Wang Yong , Ritzo Brandon , Gu Li-Qun
Published: December 2014

Ag(i) could modulate the stability of dsDNA which contains cytosine and cytosine modifications in a salt concentration dependent manner.
Thienopyrrole and selenophenopyrrole donor fused with benzotriazole acceptor: microwave assisted synthesis and electrochemical polymerization
Authors: Ghosh Sirina , Bedi Anjan , Zade Sanjio S.
Published: December 2014

Thieno-/selenophenopyrrole fused substituted benzotriazoles were synthesized by microwave assisted cyclization with reduced reaction times. Electrochemically obtained polymers of the benzotriazoles showed the formation of a polaron and bipolaron with a 0.1 V bias difference.
Waste to wealth: a sustainable aquaponic system based on residual nitrogen photoconversion
Authors: Khakyzadeh Vahid , Luque Rafael , Zolfigol Mohammad Ali , Vahidian Hadi Rezaei , Salehzadeh Hamid , Moradi Vahid , Soleymani Ali Reza , Moosavi-Zare Ahmad Reza , Xu Kun
Published: December 2014

A simple and innovative concept for a micro-aquaponic system (MAS) to valorize residual nitrogenviaphotocatalytic conversion was developed.
Asymmetric synthesis of amino-benzothiazol derivatives by additions of 2-lithiated benzothiazoles to (S)-N-t-butylsulfinyl-ketimines
Authors: Dai Yanling , Xie Chen , Wu Lingmin , Mei Haibo , Soloshonok Vadim A. , Han Jianlin , Pan Yi
Published: December 2014

We reported the asymmetric Mannich reactions between lithium-benzothiazoles and (S)-N-tert-butanesulfinylketimines, which gave unknown type of amino-benzothiazol derivatives of high pharmaceutical potential with up to 96% yields and 99 : 1 diastereoselectivities.
Structure of the DMPC lipid bilayer ripple phase
Authors: Akabori Kiyotaka , Nagle John F.
Published: December 2014

High resolution X-ray study provides new insight for the enigmatic ripple phase in lipid bilayers.
Inkjet printing for direct micropatterning of a superhydrophobic surface: toward biomimetic fog harvesting surfaces
Authors: Zhang Lianbin , Wu Jinbo , Hedhili Mohamed Nejib , Yang Xiulin , Wang Peng
Published: December 2014

Direct micropatterning of superhydrophilicity on superhydrophobic surfaces was achieved by inkjet printing a mussel-inspired ink of dopamine solution onto the superhydrophobic surface, followed by the formation of polydopamine. The micropatterned superhydrophobic surfaces exhibited an enhanced fog-harvesting efficiency.
Transparent settlement model between mobile network operator and mobile voice over Internet protocol operator
Authors: Mfupe Luzango Pangani , Mzyece Mjumo , Kurien Anish Mathew
Published: December 2014

Advances in technology have enabled network‐less mobile voice over internet protocol operator (MVoIPO) to offer data services (i.e. voice, text and video) to mobile network operator's (MNO's) subscribers through an application enabled on subscriber's user equipment using MNO's packet‐based cellular network infrastructure. However, this raises the problem of how to handle interconnection settlements between the two types of operators, particularly how to deal with users who now have the ability to make ‘free’ on‐net MVoIP calls among themselves within the MNO's network. This study proposes a service level agreement‐based transparent settlement model (TSM) to solve this problem. The model is based on concepts of achievement and reward, not violation and punishment. The TSM calculates the MVoIPO's throughput distribution by monitoring the variations of peaks and troughs at the edge of a network. This facilitates the determination of conformance and non‐conformance levels to the pre‐set throughput thresholds and, subsequently, the issuing of compensation to the MVoIPO by the MNO as a result of generating an economically acceptable volume of data traffic.
An enhanced role for an energy storage system in a microgrid with converter‐interfaced sources
Authors: Oureilidis Konstantinos O. , Demoulias Charis S.
Published: December 2014

An enhanced role for the energy storage system (ESS), strategically placed at the point of common coupling (PCC) of the microgrid with the utility grid, is proposed. During island operation, the ESS ensures that the frequency and magnitude of the voltage will remain within the limits specified by the Standard EN 50160. By implementing an adjustable droop control method, the distributed energy resources (DERs) adjust their active and reactive powers in order to fulfil the load demand. When the grid is recovered, the ESS detects its presence and achieves a seamless synchronisation of the microgrid with the main grid, without any kind of communication. In grid‐connected mode, the DERs deliver their available active power, whereas their reactive power is determined by a zero‐sequence voltage. This voltage is injected by the ESS and aims to the zeroing of the amount of reactive power at the PCC. In this way, a reduction of power losses in the distribution lines of the microgrid is achieved. The effectiveness of the proposed control method in all operation modes, without any physical communication means, is demonstrated through detailed simulation in a representative microgrid with DERs fed by photovoltaics.
Spin-transport effects in electron systems on liquid helium surfaces
Authors: Kalinenko A. N. , Kopeliovich A. I. , Pyshkin P. V. , Yanovsky A. V.
Published: December 2014

Transport phenomena are examined in electron systems on liquid helium surfaces in strong nonquantizing nonuniform magnetic fields. For applied electric fields with frequencies low enough that an equilibrium distribution of the spins along the conducting surface can develop during the wave period, the electrical resistance is determined by different current carrier scattering processes than in the uniform case. Spin nonuniformity makes electron-electron collisions efficient with respect to momentum loss, so that galvanomagnetic effects differ substantially from the Drude-Lorentz theory. A nonstationary spin-electron effect is found in a direction perpendicular to the applied electric field. The evolution of the transport properties following application of a nonuniform magnetic field is discussed.
Linear magneto-optical effect in the incommensurate phase of antiferromagnetic LiNiPO4
Authors: Kharchenko Yu. M. , Miloslavskaya O. V. , Kharchenko M. F.
Published: December 2014

A linear magneto-optical effect, birefringence of linearly polarized light that is directly proportional to magnetic field strength, is observed in magnetoelectric crystals of the orthophosphate LiNiPO4. This effect is especially pronounced in the incommensurate antiferromagnetic phase of the crystal. The linear magneto-optical effect indicates that the magnetic symmetry groups of the incommensurate, as well as the commensurate, phases of antiferromagnetic LiNiPO4 lack an anti-inversion operation. This fact is consistent with the existence of ultraweak ferromagnetism in the crystal and indicates that this antiferromagnet has more complicated magnetic structures than those found in neutron diffraction experiments.
Specific aspects of heat transfer in solid tetrahydrofuran
Authors: Konstantinov V. A. , Sagan V. V. , Revyakin V. P. , Karachevtseva A. V.
Published: December 2014

The isochoric thermal conductivity of solid tetrahydrofuran C4H8O (a cyclic hydrocarbon with pseudorotational motion of molecules) was studied using samples of different density in the temperature range 120−180 K. For all the samples, the isochoric thermal conductivity was found to decrease with temperature following a much weaker dependence than 1/T. The experimental data were interpreted in terms of the Debye model of thermal conductivity considering heat transfer by both low-frequency phonons and “diffuse” modes. No significant contribution to the thermal conductivity by pseudorotation motion of the molecules was found.
Design and development of an in-line sputtering system and process development of thin film multilayer neutron supermirrors
Authors: Biswas A. , Sampathkumar R. , Kumar Ajaya , Bhattacharyya D. , Sahoo N. K. , Lagoo K. D. , Veerapur R. D. , Padmanabhan M. , Puri R. K. , Bhattacharya Debarati , Singh Surendra , Basu S.
Published: December 2014

Neutron supermirrors and supermirror polarizers are thin film multilayer based devices which are used for reflecting and polarizing neutrons in various neutron based experiments. In the present communication, the in-house development of a 9 m long in-line dc sputtering system has been described which is suitable for deposition of neutron supermirrors on large size (1500 mm × 150 mm) substrates and in large numbers. The optimisation process of deposition of Co and Ti thin film, Co/Ti periodic multilayers, and a-periodic supermirrors have also been described. The system has been used to deposit thin film multilayer supermirror polarizers which show high reflectivity up to a reasonably large critical wavevector transfer of ∼0.06 Å−1 (corresponding to m = 2.5, i.e., 2.5 times critical wavevector transfer of natural Ni). The computer code for designing these supermirrors has also been developed in-house.
Theoretical and computer simulation study of phase coexistence of nonadditive hard-disk mixtures
Authors: Fiumara Giacomo , Pandaram Owen D. , Pellicane Giuseppe , Saija Franz
Published: December 2014

We have studied the equation of state (EOS) and the equilibrium behavior of a two-component mixture of equal-sized, nonadditive hard disks with an interspecies collision diameter that is larger than that of each component. For this purpose, we have calculated the fifth virial coefficient by evaluating numerically the irreducible cluster integrals by a Monte Carlo method. This information is used to calculate both the virial equation of state and an equation of state based on a resummation of the virial expansion. Then, the fluid-fluid phase coexistence boundaries are determined by integrating the EOS so as to obtain the free energy of the system. Canonical and Gibbs ensemble Monte Carlo simulations over a wide range of nonadditivity are also performed in order to provide a benchmark to the theoretical predictions.
Coverage dependent non-adiabaticity of CO on a copper surface
Authors: Omiya Takuma , Arnolds Heike
Published: December 2014

We have studied the coverage-dependent energy transfer dynamics between hot electrons and CO on Cu(110) with femtosecond visible pump, sum frequency probe spectroscopy. We find that transients of the C–O stretch frequency display a red shift, which increases from 3 cm−1 at 0.1 ML to 9 cm−1 at 0.77 ML. Analysis of the transients reveals that the non-adiabatic coupling between the adsorbate vibrational motion and the electrons becomes stronger with increasing coverage. This trend requires the frustrated rotational mode to be the cause of the non-adiabatic behavior, even for relatively weak laser excitation of the adsorbate. We attribute the coverage dependence to both an increase in the adsorbate electronic density of states and an increasingly anharmonic potential energy surface caused by repulsive interactions between neighboring CO adsorbates. This work thus reveals adsorbate-adsorbate interactions as a new way to control adsorbate non-adiabaticity.
Gyration eigenfrequencies of vertically coupled vortices in layered magnetic disks
Authors: Luo Y. M. , Zhou C. , Won C. , Wu Y. Z.
Published: December 2014

The dynamic properties of vertically coupled vortices in two magnetic nanodisks were studied using numerical simulations and analytical calculations. If the core polarizations of the two vortices are parallel, there exist two distinct normal modes with two distinct eigenfrequencies corresponding to the apparent complex motions of two vortices. Conversely, only a degenerate mode with a single eigenfrequency exists when the cores have opposite polarization. We show that the gyration eigenfrequencies can be tuned by changing the coupling strength, i.e., the separation between the disks. The dependence of the normal modes and the eigenfrequencies on the relative vortex-state configuration can be well understood based on the analytic model.
Mode-space energy distribution in instability-driven plasma turbulence
Authors: Terry P. W. , Makwana K. D. , Pueschel M. J. , Hatch D. R. , Jenko F. , Merz F.
Published: December 2014

Energy transfer to damped modes in gyrokinetic ion temperature gradient driven turbulence is studied to understand the transfer dynamics and find scaling representations for the heavily populated mode space. Proper orthogonal and linear eigenmode decompositions are introduced and examined to assess whether modes are well-resolved and what scales they encompass. It is observed that damped modes across a range of inhomogeneous scales receive energy simultaneously and directly from the unstable mode, constituting a form of parallel transfer, distinct from the serial mode-to-mode transfer of the wavenumber cascade of hydrodynamic turbulence. Controlling for modes that are well resolved and labeling the modes of the linear decomposition in order of damping rate, energy transfer in the mode space satisfies an equipartition of the energy dissipation rate, leading to a simple rule for the distribution of energy in the space of damped modes. Energy dissipation rate equipartition is the form that the canonical nonlinear invariance of energy transfer assumes in a dissipation range with parallel rather than serial transfer.
Hybrid nanoantennas for directional emission enhancement
Authors: Rusak Evgenia , Staude Isabelle , Decker Manuel , Sautter Jürgen , Miroshnichenko Andrey E. , Powell David A. , Neshev Dragomir N. , Kivshar Yuri S.
Published: December 2014

Plasmonic and dielectric nanoparticles offer complementary strengths regarding their use as optical antenna elements. While plasmonic nanoparticles are well-known to provide strong decay rate enhancement for localized emitters, all-dielectric nanoparticles can enable high directivity combined with low losses. Here, we suggest a hybrid metal-dielectric nanoantenna consisting of a gold nanorod and a silicon nanodisk, which combines all these advantages. Our numerical analysis reveals a giant enhancement of directional emission together with simultaneously high radiation efficiency (exceeding 70%). The suggested hybrid nanoantenna has a subwavelength footprint, and all parameters and materials are chosen to be compatible with fabrication by two-step electron-beam lithography.
Photon mirror acceleration in the quantum regime
Authors: Mendonça J. T. , Fedele R.
Published: December 2014

Reflection of an electron beam by an intense laser pulse is considered. This is the so-called photon mirror configuration for laser acceleration in vacuum, where the energy of the incident electron beam is nearly double-Doppler shifted due to reflection on the laser pulse front. A wave-electron optical description for electron reflection and resonant backscattering, due to both linear electric field force and quadratic ponderomotive force, is provided beyond the paraxial approximation. This is done by assuming that the single electron of the beam is spin-less and therefore its motion can be described by a quantum scalar field whose spatiotemporal evolution is governed by the Klein-Gordon equation (Klein-Gordon field). Our present model, not only confirms the classical results but also shows the occurrence of purely quantum effects, such as partial reflection of the incident electron beam and enhanced backscattering due to Bragg resonance.
Finite toroidal flow generated by unstable tearing mode in a toroidal plasma
Authors: Hao G. Z. , Liu Y. Q. , Wang A. K. , Sun Y. , Xu Y. H. , He H. D. , Xu M. , Qu H. P. , Peng X. D. , Xu J. Q. , Cui S. Y. , Qiu X. M.
Published: December 2014

The neoclassical toroidal plasma viscosity torque and electromagnetic torque, generated by tearing mode (TM) in a toroidal plasma, are numerically investigated using the MARS-Q code [Liu et al., Phys. Plasmas 20, 042503 (2013)]. It is found that an initially unstable tearing mode can intrinsically drive a toroidal plasma flow resulting in a steady state solution, in the absence of the external momentum input and external magnetic field perturbation. The saturated flow is in the order of 0.5%ωA at the q=2 rational surface in the considered case, with q and ωA being the safety factor and the Alfven frequency at the magnetic axis, respectively. The generation of the toroidal flow is robust, being insensitive to the given amplitude of the perturbation at initial state. On the other hand, the flow amplitude increases with increasing the plasma resistivity. Furthermore, the initially unstable tearing mode is fully stabilized by non-linear interaction with the self-generated toroidal flow.
Evolution of the modulus of the total magnetic moment of a ferromagnet after ultrafast demagnetization
Authors: Yastremsky I. A.
Published: December 2014

The longitudinal relaxation rate of the total magnetization to its equilibrium value after ultrafast demagnetization by a femtosecond laser pulse is governed by two phenomena: the homogeneous evolution of magnetization and the motion of the wavefront into the demagnetized region. If the demagnetized region is sufficiently large, the homogeneous evolution dominates. However, as the diameter of the demagnetized region decreases, the relative contribution of the wavefront increases, and in the case when a femtosecond laser pulse is focused to a diffraction-limited minimum size, the wavefront can significantly increase the longitudinal relaxation rate.
Interface stress development in the Cu/Ag nanostructured multilayered film during the tensile deformation
Authors: Su R. , Li L. , Nie Z. H. , Zhang Q. H. , Wang Y. D. , Zhou X. T. , Wu Y. D. , Hui X. D. , Li X. J. , Wang M. G.
Published: December 2014

Cu/Ag nanostructured multilayered films (NMFs) with different stacking sequences were investigated by synchrotron X-ray diffraction during the tensile deformations for interface stress study. The lattice strains were carefully traced and the stress partition, which usually occurs in the multiphase bulk metallic materials during plastic deformations, was first quantitatively analyzed in the NMFs here. The interface stress of the Cu/Ag NMFs was carefully analyzed during the tensile deformation and the results revealed that the interface stress was along the loading direction and exhibited three-stage evolution. This tensile interface stress has a detrimental effect on the deformation, leading to the early fracture of the NMFs.
Stabilization of solitons under competing nonlinearities by external potentials
Authors: Zegadlo Krzysztof B. , Wasak Tomasz , Malomed Boris A. , Karpierz Miroslaw A. , Trippenbach Marek
Published: December 2014

We report results of the analysis for families of one-dimensional (1D) trapped solitons, created by competing self-focusing (SF) quintic and self-defocusing (SDF) cubic nonlinear terms. Two trapping potentials are considered, the harmonic-oscillator (HO) and delta-functional ones. The models apply to optical solitons in colloidal waveguides and other photonic media, and to matter-wave solitons in Bose-Einstein condensates loaded into a quasi-1D trap. For the HO potential, the results are obtained in an approximate form, using the variational and Thomas-Fermi approximations, and in a full numerical form, including the ground state and the first antisymmetric excited one. For the delta-functional attractive potential, the results are produced in a fully analytical form, and verified by means of numerical methods. Both exponentially localized solitons and weakly localized trapped modes are found for the delta-functional potential. The most essential conclusions concern the applicability of competing Vakhitov-Kolokolov (VK) and anti-VK criteria to the identification of the stability of solitons created under the action of the competing SF and SDF terms.
Fermi level pinning induced electrostatic fields and band bending at organic heterojunctions
Authors: Akaike K. , Koch N. , Oehzelt M.
Published: December 2014

The energy level alignment at interfaces between organic semiconductors is of direct relevance to understand charge carrier generation and recombination in organic electronic devices. Commonly, work function changes observed upon interface formation are interpreted as interface dipoles. In this study, using ultraviolet and X-ray photoelectron spectroscopy, complemented by electrostatic calculations, we find a huge work function decrease of up to 1.4 eV at the C60 (bottom layer)/zinc phthalocyanine (ZnPc, top layer) interface prepared on a molybdenum trioxide (MoO3) substrate. However, detailed measurements of the energy level shifts and electrostatic calculations reveal that no interface dipole occurs. Instead, upon ZnPc deposition, a linear electrostatic potential gradient is generated across the C60 layer due to Fermi level pinning of ZnPc on the high work function C60/MoO3 substrate, and associated band-bending within the ZnPc layer. This finding is generally of importance for understanding organic heterojunctions when Fermi level pinning is involved, as induced electrostatic fields alter the energy level alignment significantly.
Development of a new virtual diagnostic for V3FIT
Authors: Trevisan G. L. , Cianciosa M. R. , Terranova D. , Hanson J. D.
Published: December 2014

The determination of plasma equilibria from diagnostic information is a fundamental issue. V3FIT is a fully three-dimensional reconstruction code capable of solving the inverse problem using both magnetic and kinetic measurements. It uses VMEC as core equilibrium solver and supports both free- and fixed-boundary reconstruction approaches. In fixed-boundary mode VMEC does not use explicit information about currents in external coils, even though it has important effects on the shape of the safety factor profile. Indeed, the edge safety factor influences the reversal position in RFP plasmas, which then determines the position of the m = 0 island chain and the edge transport properties. In order to exploit such information a new virtual diagnostic has been developed, that thanks to Ampère's law relates the external current through the center of the torus to the circulation of the toroidal magnetic field on the outermost flux surface. The reconstructions that exploit the new diagnostic are indeed found to better interpret the experimental data with respect to edge physics.
Giant room-temperature magnetodielectric coupling in spark plasma sintered brownmillerite ceramics
Authors: Wu J. W. , Wang J. , Liu G. , Wu Y. J. , Liu X. Q. , Chen X. M.
Published: December 2014

The dielectric, magnetic, and magnetodielectric properties of Ca2FeAO5+δ (A = Al, Ga) ceramics were investigated together with their crystal structures. Rietveld refinement of the X-ray diffraction data indicated that the space group of the Ca2FeAlO5+δ ceramic was Ibm2, whereas that of the Ca2FeGaO5+δ ceramic was Pcmn. Dielectric relaxation above room temperature, originating from the Maxwell–Wagner effect and polaronic hole hopping between Fe3+ and Fe4+ ions, was observed in both ceramics. Weak ferrimagnetic behavior was identified from the magnetic-field-dependent magnetization in these ceramics, which was attributed to the non-cancelled spins of the antiferromagnetic-ordered Fe3+ and Fe4+ ions. An intrinsic, giant, room-temperature magnetodielectric coefficient of up to −23.3% was achieved in the Ca2FeAlO5+δ ceramic at 50 MHz, which was attributed to the suppression of charge fluctuations of Fe3+ and Fe4+ ions in the magnetic field.
Enhanced piezoelectric response in the artificial ferroelectric polymer multilayers
Authors: Zhao X. L. , Wang J. L. , Tian B. B. , Liu B. L. , Wang X. D. , Sun S. , Zou Y. H. , Lin T. , Sun J. L. , Meng X. J. , Chu J. H.
Published: December 2014

An actuator with a high piezoelectric response, the ferroelectric polymer multilayer actuator, is described. The ferroelectric polymer multilayers consisting of alternative ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer and relaxor poly(vinylidene fluoride-trifluoroethylene-chlorofloroethylene) (P(VDF-TrFE-CFE)) terpolymer with different periodicities and fixed total thickness are prepared by the Langmuir-Blodgett technique. Both X-ray diffraction and Raman spectroscopic measurements indicate that the structure of the multilayer with thin alternating layer is similar to that of the ferroelectric copolymer. Compared with that of the copolymer, it is found that the piezoelectric coefficient of the multilayer could be improved by 57%. We attributed the enhanced piezoelectric response of the multilayers to the internal electric fields that arises from the electrostatic couplings between different layers.
Low temperature epitaxy of Ge-Sb-Te films on BaF2 (111) by pulsed laser deposition
Authors: Thelander E. , Gerlach J. W. , Ross U. , Lotnyk A. , Rauschenbach B.
Published: December 2014

Pulsed laser deposition was employed to deposit epitaxial Ge2Sb2Te5-layers on the (111) plane of BaF2 single crystal substrates. X-ray diffraction measurements show a process temperature window for epitaxial growth between 85 °C and 295 °C. No crystalline growth is observed for lower temperatures, whereas higher temperatures lead to strong desorption of the film constituents. The films are of hexagonal structure with lattice parameters consistent with existing models. X-ray pole figure measurements reveal that the films grow with one single out-of-plane crystal orientation, but rotational twin domains are present. The out-of-plane epitaxial relationship is determined to be Ge2Sb2Te5(0001) || BaF2(111), whereas the in-plane relationship is characterized by two directions, i.e., Ge2Sb2Te5 [-12-10] || BaF2[1-10] and Ge2Sb2Te5[1-210] || BaF2[1-10]. Aberration-corrected high-resolution scanning transmission electron microscopy was used to resolve the local atomic structure and confirm the hexagonal structure of the films.
ZnO:H indium-free transparent conductive electrodes for active-matrix display applications
Authors: Chen Shuming , Wang Sisi
Published: December 2014

Transparent conductive electrodes based on hydrogen (H)-doped zinc oxide (ZnO) have been proposed for active-matrix (AM) display applications. When fabricated with optimal H plasma power and optimal plasma treatment time, the resulting ZnO:H films exhibit low sheet resistance of 200 Ω/◻ and high average transmission of 85% at a film thickness of 150 nm. The demonstrated transparent conductive ZnO:H films can potentially replace indium-tin-oxide and serve as pixel electrodes for organic light-emitting diodes as well as source/drain electrodes for ZnO-based thin-film transistors. Use of the proposed ZnO:H electrodes means that two photomask stages can be removed from the fabrication process flow for ZnO-based AM backplanes.
Multi-scale simulation of the stability and diffusion of lithium in the presence of a 90° partial dislocation in silicon
Authors: Wang Chao-Ying , Yang Li-Jun , Zhao Wei , Meng Qing-Yuan , Wu Guo-Xun , Wang Bao-Lai , Li Chen-Liang
Published: December 2014

The stable positions, binding energies, and dynamic properties of Li impurity in the presence of a 90° partial dislocation in Si have been studied by using the multi-scale simulation method. The corresponding results are compared with the defect-free Si crystal in order to reflect how the dislocation defect affects the performances of Li-ion batteries (LIBs) at the atomic level. It is found that the inserted Li atom in the dislocation core and nearest regions is more stable, since the binding energies are 0.13 eV to 0.52 eV larger than the bulk Si. Moreover, it is easier for Li atom to diffuse into those defect areas and harder to diffuse out. Thus, Li dopant may tend to congregate in the dislocation core and nearest regions. On the other side, the 90° partial dislocation can glide in the {111} plane accompanied by the diffusion of Li impurity along the pentagon ring of core. In addition, the spacious heptagon ring of dislocation core can lower the migration barrier of Li atom from 0.63 eV to 0.34 eV, which will enhance the motion of the dopant. Therefore, the presence of 90° partial dislocations may provide a fast and favorable diffusion path for the congregated Li impurity, which finally facilitates the lithiation of LIBs.
The behavior of the electron plasma boundary in ultraintense laser–highly overdense plasma interaction
Authors: Sánchez-Arriaga G. , Sanz J. , Debayle A. , Lehmann G.
Published: December 2014

The structural stability of the laser/plasma interaction is discussed, for the case of a linearly polarized laser beam interacting with a solid at normal incidence. Using a semi-analytical cold fluid model, the dynamics of the electron plasma boundary (EPB), usually related to the high-order harmonic generation and laser absorption, are presented. While the well-known J × B plasma oscillations at two times the laser frequency are recovered by the model, several other periodic in time stable solutions exist for exactly the same value of the physical parameters. This novel behavior highlights the importance of the laser pulse history among other factors. Some important features, such as the synchronization between the incident laser and the EPB oscillation, depend on the solution under consideration. A description of the possible types of stable oscillations in a parametric plane involving plasma density and laser amplitude is presented. The semi-analytical model is compared with particle-in-cell and semi-Lagrangian Vlasov simulations. They show that, among all the stable solutions, the plasma preferentially evolves to a state with the EPB oscillating twice faster than the laser. The effect of the plasma temperature and the existence of a ramp in the ion density profile are also discussed.
Control of focusing fields for positron acceleration in nonlinear plasma wakes using multiple laser modes
Authors: Yu L.-L. , Schroeder C. B. , Li F.-Y. , Benedetti C. , Chen M. , Weng S.-M. , Sheng Z.-M. , Esarey E.
Published: December 2014

Control of transverse wakefields in the nonlinear laser-driven bubble regime using a combination of Hermite-Gaussian laser modes is proposed. By controlling the relative intensity ratio of the two laser modes, the focusing force can be controlled, enabling matched beam propagation for emittance preservation. A ring bubble can be generated with a large longitudinal accelerating field and a transverse focusing field suitable for positron beam focusing and acceleration.
Si based GeSn photoconductors with a 1.63 A/W peak responsivity and a 2.4 μm long-wavelength cutoff
Authors: Conley Benjamin R. , Margetis Joe , Du Wei , Tran Huong , Mosleh Aboozar , Ghetmiri Seyed Amir , Tolle John , Sun Greg , Soref Richard , Li Baohua , Naseem Hameed A. , Yu Shui-Qing
Published: December 2014

Thin-film Ge0.9Sn0.1 structures were grown by reduced-pressure chemical vapor deposition and were fabricated into photoconductors on Si substrates using a CMOS-compatible process. The temperature-dependent responsivity and specific detectivity (D*) were measured from 300 K down to 77 K. The peak responsivity of 1.63 A/W measured at 1.55 μm and 77 K indicates an enhanced responsivity due to photoconductive gain. The measured spectral response of these devices extends to 2.4 μm at 300 K, and to 2.2 μm at 77 K. From analysis of the carrier drift and photoconductive gain measurements, we have estimated the carrier lifetime of this Ge0.9Sn0.1 thin film. The longest measured effective carrier lifetime of 1.0 × 10−6 s was observed at 77 K.