bluuebunny/crossref_metadata_2025 huggingface dataset:
First principle investigations on transport properties in porphyrin, hexaphyrin, and hexathia[26π]annulene molecular junction devices
Authors: Naskar Sumit , Das Mousumi
Published: June 2020

The quantum charge transport calculations at metal–molecule–metal junctions lead to various electronic properties suitable in the field of miniaturization. Finite bias-dependent conductivity is calculated through porphyrin, hexaphyrin, and hexathia[26π]annulene molecular junction devices connected to the metallic or semiconducting electrode using non-equilibrium Green's function technique based on the density functional theory method. The (I−V) characteristic curves calculated for various donor–insulator–acceptor (D–σ–A) devices show a Ohmic, diode, or rectifier-like nature depending on the donor acceptor substitution effect in the above molecules connected to the electrode. The rectification ratio R (I+/I− or I−/I+) calculated for such devices varies from 2 to 70, and maximum R is calculated for the D–A-substituted porphyrin molecular junction. The I−V characteristics, rectification, and negative differential resistance effect found in such devices are well analyzed by projected density of states and molecular-projected self-consistent Hamiltonian eigenstate, local density of state calculations. Molecular conductivity calculations in D–σ–A devices using porphyrin, hexaphyrin, and hexathia[26π]annulene show promise in the field of molecular electronics and memory storage devices.
Suppression of the ion drag force on dust in magnetized plasmas
Authors: James Lloyd , Coppins Michael
Published: June 2020

Modeling the transport of “dust” particles in a magnetically confined plasma device is an area of active research and requires a detailed understanding of the forces experienced by dust immersed in a plasma. One of the most significant of these is the “ion drag force.” Dust transport codes employ a model of this force that was not specifically designed for fusion plasmas and so does not consider the relevance of strong magnetic fields. However, it is shown here that the effect of magnetic fields on the ion drag force is significant for such plasmas. In this work, the Monte Carlo code DiMPl is employed to perform the first detailed characterization of the dependence of the ion drag force on magnetic fields. A semi-empirical model of this dependence is fitted onto the simulation data, so that these magnetic effects may be straightforwardly captured by dust transport codes. The limiting behavior of the ion drag force in the case of very strong fields is derived analytically and shown to be consistent with the simulation results. The validity of the results is further motivated through a novel theoretical treatment of the ion drag force at intermediate magnetic field strengths.
Sensitive radiofrequency readout of quantum dots using an ultra-low-noise SQUID amplifier
Authors: Schupp F. J. , Vigneau F. , Wen Y. , Mavalankar A. , Griffiths J. , Jones G. A. C. , Farrer I. , Ritchie D. A. , Smith C. G. , Camenzind L. C. , Yu L. , Zumbühl D. M. , Briggs G. A. D. , Ares N. , Laird E. A.
Published: June 2020

Fault-tolerant spin-based quantum computers will require fast and accurate qubit read out. This can be achieved using radiofrequency reflectometry given sufficient sensitivity to the change in quantum capacitance associated with the qubit states. Here, we demonstrate a 23-fold improvement in capacitance sensitivity by supplementing a cryogenic semiconductor amplifier with a SQUID preamplifier. The SQUID amplifier operates at a frequency near 200 MHz and achieves a noise temperature below 600 mK when integrated into a reflectometry circuit, which is within a factor 120 of the quantum limit. It enables a record sensitivity to capacitance of 0.07aF/Hz. The setup is used to acquire charge stability diagrams of a gate-defined double quantum dot in a short time with a signal-to-noise ration of about 38 in 1μs of integration time.
Stabilization of exponential number of discrete remanent states with localized spin–orbit torques
Authors: Das Shubhankar , Zaig Ariel , Schultz Moty , Klein Lior
Published: June 2020

Using bilayer films of β-Ta/Ni0.8Fe0.2, we fabricate structures consisting of two, three, and four crossing ellipses, which exhibit shape-induced bi-axial, tri-axial, and quadro-axial magnetic anisotropy in the crossing area, respectively. Structures consisting of N crossing ellipses can be stabilized in 2N remanent states by applying (and removing) an external magnetic field. However, we show that with field-free spin–orbit torques induced by flowing currents in individual ellipses, the number of remanent states grows to 2N. Furthermore, when the current flows between the edges of different ellipses, the number of remanent states jumps to 22N, including states that exhibit a π-Néel domain wall in the overlap area. The very large number of accessible remanent magnetic states that are exhibited by the relatively simple magnetic structures paves the way for intriguing spintronics applications including memory devices.
Quantum confinement of coherent acoustic phonons in transferred single-crystalline bismuth nanofilms
Authors: He Feng , Walker Emily S. , Zhou Yongjian , Muschinske Sarah E. , Bank Seth R. , Wang Yaguo
Published: June 2020

Coherent acoustic phonon dynamics in single-crystalline bismuth nanofilms transferred to a glass substrate were investigated with ultrafast pump–probe spectroscopy. Coherent phonon signals were substantially enhanced by more than four times when compared with as-grown films on Si (111) substrates. Furthermore, more than 10% reduction of the acoustic phonon velocity was observed when the film thickness decreases to 22 nm, which is attributed to the modified phonon dispersion in extremely thin films from quantum confinement effects.
Scaling of quadratic and linear magneto-optic Kerr effect spectra with L21 ordering of Co2MnSi Heusler compound
Authors: Silber Robin , Král Daniel , Stejskal Ondřej , Kubota Takahide , Ando Yasuo , Pištora Jaromír , Veis Martin , Hamrle Jaroslav , Kuschel Timo
Published: June 2020

Spectral ellipsometry is a useful technique allowing fast, nondestructive, and contactless characterization of thin films and constituent materials. In this Letter, we show that both the linear magneto-optic Kerr effect (LinMOKE, proportional to the magnetization M) and the quadratic MOKE (QMOKE, proportional to M2) can be a useful extension of spectral ellipsometry and are able to sense the crystallographic ordering of Heusler compounds. This is demonstrated for the Heusler compound Co2MnSi, which has a crystallographic transition from a B2 to an L21 structure with increasing annealing temperature Ta. We investigated a set of Co2MnSi thin films deposited on MgO(001) substrates and annealed from 300 to 500 °C. The amplitude of LinMOKE and QMOKE spectra, detected in the extended visible spectral range of 0.8–5.5 eV, scales linearly with Ta, and this effect is pronounced at the resonant peaks of the QMOKE spectra below 2.0 eV. Furthermore, the spectra of the magneto-optic (MO) parameters, which fully describe the MO response of Co2MnSi up to the second order in M, are obtained depending on Ta. Finally, the spectra are compared with ab initio calculations of a purely L21-ordered Co2MnSi Heusler compound.
Monitoring the evolution of intersite and interexciton coherence in electronic excitation transfer via wave-packet interferometry
Authors: Kiessling Alexis J. , Cina Jeffrey A.
Published: June 2020

We detail an experimental strategy for tracking the generation and time-development of electronic coherence within the singly excited manifold of an energy-transfer dimer. The technique requires that the two monomers have nonparallel electronic transition-dipole moments and that these possess fixed orientations in space. It makes use of two-dimensional wave-packet interferometry (WPI or whoopee) measurements in which the A, B, C, and D pulses have respective polarizations e, e, e, and e′. In the case of energy-transfer coupling that is weak or strong compared to electronic–nuclear interactions, it is convenient to follow the evolution of intersite or interexciton coherence, respectively. Under weak coupling, e could be perpendicular to the acceptor chromophore’s transition dipole moment and the unit vector e′ would be perpendicular to the donor’s transition dipole. Under strong coupling, e could be perpendicular to the ground-to-excited transition dipole to the lower exciton level and e′ would be perpendicular to the ground-to-excited transition dipole to the upper exciton level. If the required spatial orientation can be realized for an entire ensemble, experiments of the kind proposed could be performed by either conventional four-wave-mixing or fluorescence-detected WPI methods. Alternatively, fluorescence-detected whoopee experiments of this kind could be carried out on a single energy-transfer dimer of fixed orientation. We exhibit detailed theoretical expressions for the desired WPI signal, explain the physical origin of electronic coherence detection, and show calculated observed-coherence signals for model dimers with one, two, or three internal vibrational modes per monomer and both weak and strong energy-transfer coupling.
Photonics based perfect secrecy cryptography: Toward fully classical implementations
Authors: Mazzone Valerio , Falco Andrea Di , Cruz Al , Fratalocchi Andrea
Published: June 2020

Developing an unbreakable cryptography is a long-standing question and a global challenge in the internet era. Photonics technologies are at the frontline of research, aiming at providing the ultimate system with capability to end the cybercrime industry by changing the way information is treated and protected now and in the long run. Such a perspective discusses some of the current challenges as well as opportunities that classical and quantum systems open in the field of cryptography as both a field of science and engineering.
Recent developments, challenges, and pathways to stable dropwise condensation: A perspective
Authors: Ma Jingcheng , Sett Soumyadip , Cha Hyeongyun , Yan Xiao , Miljkovic Nenad
Published: June 2020

Dropwise condensation (DWC) on non-wetting surfaces has remarkable potential to enhance heat transfer performance compared to filmwise condensation on wetting substrates. In this article, we discuss important recent developments and challenges in the field of DWC, including durability of DWC-promoting coatings, DWC of low surface tension fluids, physical mechanisms governing DWC, unconventional methods to achieve DWC, and promising metrology techniques for DWC. We end the article by providing a road map detailing where we believe the community should direct both fundamental and applied efforts in order to solve the identified century-old challenges that limit DWC implementation.
Bound state in the continuum in topological inductor–capacitor circuit
Authors: Li Zhuangzhuang , Wu Jien , Huang Xueqin , Lu Jiuyang , Li Feng , Deng Weiyin , Liu Zhengyou
Published: June 2020

Bound states in the continuum (BICs) have received increasing attention from researchers because of their potential applications in photonic crystal fibers, as well as in lasing, sensing, and surface acoustic wave devices. BICs have been experimentally observed in acoustic resonators, photonic crystal slabs, and optical waveguides. Herein, we constructed a topological inductor–capacitor (LC) circuit to observe BICs; the circuit consists of two identical LC Su–Schrieffer–Heeger chains coupled using a middle chain with capacitors. In addition, a BIC in a non-Hermitian system was also experimentally observed by adding different resistances to the original LC circuit. Our experimental and simulation results thus prove that an electrical circuit could be used as a platform to realize BIC. Furthermore, we believe that such a circuit can be extended to two- and three-dimensional models and higher frequencies, making it suitable for electrical device applications, such as antennae, filters, and radio frequency devices.
Dynamic evolution of flux distributions in a pulse-driven superconductor by high-speed magneto-optical imaging
Authors: Kurokawa H. , Kinoshita Y. , Nabeshima F. , Tokunaga M. , Maeda A.
Published: June 2020

The accurate understanding of flux dynamics is essential for the design and operation of superconducting circuits. Time evolution of flux-density distribution in an NbN strip by the transport current was observed using high-speed magneto-optical microscopy. It was determined that even for the dynamic penetration and exclusion of vortices under the transport current, the surface barrier is essential. This feature is important for the correct understanding of the complex behavior of state-of-the-art superconducting devices.
Optical elements for anisotropic spin-wave propagation
Authors: Vogel M. , Pirro P. , Hillebrands B. , von Freymann G.
Published: June 2020

We perform micromagnetic simulations to investigate the propagation of spin-wave beams through spin-wave optical elements. Despite spin-wave propagation in magnetic media being strongly anisotropic, we use axicons to excite spin-wave Bessel–Gaussian beams and gradient-index lenses to focus spin waves in analogy to conventional optics with light in isotropic media. Moreover, we demonstrate spin-wave Fourier optics using gradient-index lenses. Our results are valid for all three possible external magnetic field orientations and thus contribute to the growing field of spin-wave optics.
Non-consensual sexting: characteristics and motives of youths who share received-intimate content without consent
Authors: Barrense-Dias Yara , Akre Christina , Auderset Diane , Leeners Brigitte , Morselli Davide , Surís Joan-Carles
Published: June 2020

Background
One of the possible negative consequences of sexting is the non-consensual sharing of received-intimate content. This study aimed to determine the characteristics and motives of youths who shared received-intimate images without consent. Methods: Data were obtained from a self-administrated Swiss survey on sexual behaviours among young adults (aged 24–26 years). Out of the 7142 participants, 5175 responded to the question ‘Have you ever shared (forwarding or showing) a sexy photograph/video of someone else (known or unknown) without consent’?; 85% had never shared (Never), 6% had shared once (Once) and 9% had shared several times (Several). Data are presented as relative risk ratios with 95% confidence intervals. Results: Participants who had shared received-intimate content without consent had higher odds of being male [2.73 (2.14–3.47)], foreign-born [1.45 (1.04–2.03)], reporting a non-heterosexual orientation [1.46 (1.10–1.93)], having sent one’s own intimate image [1.76 (1.32–2.34)] and receiving a shared-intimate image of someone unknown [4.56 (3.28–6.36)] or known [2.76 (1.52–5.01)] compared with participants who had never shared. The main reported motivations were for fun (62%), showing off (30%) and failure to realise what they were doing (9%). Conclusions: Given the reported motivations, it appears crucial to remind youths of the seriousness of non-consensual sharing. Although females may also be perpetrators, the behaviour was more prevalent among males. Prevention and education need to consider a broad range of young people in their scenarios. Even if a particular focus on understanding and preventing males’ perpetration must be considered, overall perpetration, including female’s, must be discussed.
Incels, in-groups, and ideologies
Authors: Heritage Frazer , Koller Veronika
Published: June 2020

We present a study of the online forum Reddit, specifically a sub-forum for (typically heterosexual) men who identify as
involuntary celibates or incels. Incels are an online imagined community/community of practice who wish
to, but do not, have sexual relations with women. Owing to this identity, they view themselves as non-normative within broader society and
see women and societal standards of masculinity as the cause of their problems. In this paper, we take a small corpus of 67,000 words
generated from 50 threads created, and commented on, by incels. We analyse keywords, word frequencies, and concordance lines to explore the
representation of gendered social actors. Keyword analysis reveals that references to gendered social actors are particularly salient within
this community, leading to an analysis of all such social actors in the corpus. The findings suggest that incels position different groups
of men in a hierarchy in which conventionally attractive men occupy the top position. Notably, we find that female social actors are not
placed in a similar hierarchy. An additional appraisal analysis of the most frequently occurring male and female social actors shows that
men are judged as incapacitated while women are seen as immoral, dishonest and capable of hurting men. Members of the online community also
seem preoccupied with physical attractiveness. The study opens up a number of avenues for future research, especially into the complexities
with which members of non-normative heterosexual groups simultaneously orient to and reject social norms.
“Thaz how u kno ur dum”
Authors: Chambers Eric
Published: June 2020

This study analyzes language use among a group of gay men who participate on an online messageboard (OnYourKnees), focused
on the attainment of a ‘dumb jock’ identity. Posters align with a series of qualities that largely conform to ideologies of American jock
masculinity, but at the same time satirize those ideologies: in particular, many posters view as an integral quality of dumb-jock identity
‘dumbness:’ an unwillingness/inability to engage in scholarly/academic pursuits. The repeated citationality of dumbness as a positive
quality creates a distinct identity-type that posters link with erotic desire. Orthographic variation contributes to the attainment and
recognition of a jock identity: posters who identify as jocks are more likely to display non-standard American English spelling than those
who do not. This study thus highlights the importance of orthographic variation in maintaining distinct identities among local communities,
especially in a space where traditional ideologies of masculinity are recontextualized.
Activewear and other vaguery
Authors: Cohen Dana
Published: June 2020

In the literature on the mass-count distinction,
some nominals that denote groupings of objects (e.g. English
furniture) are known to display hybrid properties,
exhibiting syntactic distribution akin to prototypical non-count nominals
(substance-denoting, e.g. mud), but showing certain
semantic properties associated with plurals. This paper aims to broaden our
perspective on the properties of such nouns, focusing on their morphological
composition in three languages, English, French, and Hebrew, where nouns of this type are
frequently created through specific derivational processes. This systematic
derivation suggests that the combination of properties associated with these
nouns should not be seen as an idiosyncratic exception to the mass-count
distinction, but as a systematic category between the two.
Countability and grammatical number
Authors: Ojeda Almerindo E.
Published: June 2020

The purpose of this paper is to define number categories as government classes, and to interpret said categories semantically against models which are rich enough to support the desired interpretations. Defining number categories as government classes in terms of their cooccurrence with numerals leads to a system of five pairs of binary categories in complementary opposition: SINGULAR/COSINGULAR, DUAL/CODUAL, PAUCAL/COPAUCAL, MESAL/COMESAL, and UNIVERSAL/COUNIVERSAL. To support the interpretation of these ten categories we focus on Boolean models and compare those that split dualistically into atomistic and atomless portions with those that are uniformly atomless instead. After arguing that models for the interpertation of number should be uniformly atomless, we show how these models can support the interpretation of all count nouns regardless of number category. Particularly their cooccurrence with numerals. Key to such interpretations will be the ability to refer to atomistic structures embedded deeply within atomless models.
Comparatives in Brazilian Portuguese
Authors: Rothstein Susan , Pires De Oliveira Roberta
Published: June 2020

Comparatives in Brazilian Portuguese show that Bale and Barner’s (2009)
generalizations do not hold cross-linguistically; this leads to
reconsidering the role of cardinality in mass and count syntax. The paper
discusses contrasts in the use of naturally atomic, or object, mass nouns in
Brazilian Portuguese and English. Brazilian Portuguese has a productive bare
singular, which is analysed, following Pires de Oliveira and Rothstein (2011) as an object mass noun
with a count counterpart. However, in comparative constructions it does not
behave as Bale and Barner predict. We give an account of the relation
between counting and measuring which explains the data and we show, using
data from Hungarian, that the contrasts with English are not unique to
Brazilian Portuguese.
Countability shifts and abstract nouns
Authors: Zamparelli Roberto
Published: June 2020

The paper examines the mass-count distinction in abstract nouns, starting
from the corpus-derived observation that most of the nouns that can be used
in count or mass syntactic contexts (“elastic nouns”) are (arguably)
abstract. The paper evaluates various tests for mass-count status and
different criteria for “abstractness”, proposing seven semi-productive
meaning shifts that can result in a transition from mass to count or
vice-versa. Section 4.2
addresses the relation between abstract nouns and kinds (are bare abstract
terms “names of kinds”? What are their instances? Are they always kinds, even
as predicates? What types of meaning shifts are applicable to them?). The
possibility of a degree argument is also discussed: some count quantifiers
over abstract mass nouns range over degrees, but not all abstract nouns have
this option. We use the Bochum Countability Lexicon to detect elastic nouns
and classify them via morphological affixes, identifying some possible
meaning alternations.
High porosity and light weight graphene foam heat sink and phase change material container for thermal management
Authors: Zehri Abdelhafid , Samani Majid Kabiri , Latorre Martí Gutierrez , Nylander Andreas , Nilsson Torbjörn , Fu Yifeng , Wang Nan , Ye Lilei , Liu Johan
Published: June 2020

During the last decade, graphene foam emerged as a promising high porosity 3-dimensional (3D) structure for various applications. More specifically, it has attracted significant interest as a solution for thermal management in electronics. In this study, we investigate the possibility to use such porous materials as a heat sink and a container for a phase change material (PCM). Graphene foam (GF) was produced using chemical vapor deposition (CVD) process and attached to a thermal test chip using sintered silver nanoparticles (Ag NPs). The thermal conductivity of the graphene foam reached 1.3 W m−1 K−1, while the addition of Ag as a graphene foam silver composite (GF/Ag) enhanced further its effective thermal conductivity by 54%. Comparatively to nickel foam, GF and GF/Ag showed lower junction temperatures thanks to higher effective thermal conductivity and a better contact. A finite element model was developed to simulate the fluid flow through the foam structure model and showed a positive and a non-negligible contributions of the secondary microchannel within the graphene foam. A ratio of 15 times was found between the convective heat flux within the primary and secondary microchannel. Our paper successfully demonstrates the possibility of using such 3D porous material as a PCM container and heat sink and highlight the advantage of using the carbon-based high porosity material to take advantage of its additional secondary porosity.
Near-zero contact force atomic force microscopy investigations using active electromagnetic cantilevers
Authors: Świadkowski B , Majstrzyk W , Kunicki P , Sierakowski A , Gotszalk T
Published: June 2020

Atomic force microscopy (AFM) belongs to the high resolution and high sensitivity surface imaging technologies. In this method force interactions between the tip and the surface are observed to characterize sample properties. In the so-called contact AFM (C AFM) mode the tip is brought into continuous contact with the sample. Significant progress in the AFM technology can be obtained, when the so-called active cantilever technology is implemented in the surface measurements. The built-in deflection actuator enables very precise excitation of the cantilever. Moreover, as the mass of the beam is very small the static beam displacement can be controlled in the wide frequency range. In the experiments, which we describe in this article, we applied the so called active electromagnetic cantilevers. They integrate a conductive loop which, when immersed in the magnetic field and biased with electric current, acts as an electromagnetic deflection actuator. The induced and precisely estimated Lorentz force, which is a function of bias current, cantilever geometry and magnetic field makes the cantilever deflect. Moreover, the probe stiffness can be calibrated with lower uncertainty as in the case of standard thermomechanical analysis. NZ AFM technology required application of a novel control algorithm, called PredPID, in which the cantilever bending caused by a proportional-integral-derivative (PID) block maintaining the constant load force was predicted.
Magnetic field induced symmetry breaking in nonequilibrium quantum networks
Authors: Thingna Juzar , Manzano Daniel , Cao Jianshu
Published: June 2020

We study the effect of an applied magnetic field on the nonequilibrium transport properties of a general cubic quantum network described by a tight-binding Hamiltonian with specially designed couplings to the leads that preserve open-system symmetries. We demonstrate that the symmetry of open systems can be manipulated by the direction of the magnetic field. Starting with all the symmetries preserved in absence of a field, the anisotropic and isotropic fields systematically break the symmetries, influencing all nonequilibrium properties. For simple cubic systems, we are able to identify the steady states that comprise of pure states, bath-dependent states (nonequilibrium steady states), and also nonphysical states. As an application, we show numerically for large cubic networks that the symmetry breaking can control nonequilibrium currents and that different environmental interactions can lead to novel features which can be engineered in artificial super-lattices and cold atoms.
Quantum probing beyond pure dephasing
Authors: Tamascelli Dario , Benedetti Claudia , Breuer Heinz-Peter , Paris Matteo G A
Published: June 2020

Quantum probing is the art of exploiting simple quantum systems interacting with a complex environment to extract precise information about some environmental parameters, e.g. the temperature of the environment or its spectral density. Here we analyze the performance of a single-qubit probe in characterizing Ohmic bosonic environments at thermal equilibrium. In particular, we analyze the effects of tuning the interaction Hamiltonian between the probe and the environment, going beyond the traditional paradigm of pure dephasing. In the weak-coupling and short-time regime, we address the dynamics of the probe analytically, whereas numerical simulations are employed in the strong coupling and long-time regime. We then evaluate the quantum Fisher information for the estimation of the cutoff frequency and the temperature of the environment. Our results provide clear evidence that pure dephasing is not optimal, unless we focus attention to short times. In particular, we found several working regimes where the presence of a transverse interaction improves the maximum attainable precision, i.e. it increases the quantum Fisher information. We also explore the role of the initial state of the probe and of the probe characteristic frequency in determining the estimation precision, thus providing quantitative guidelines to design optimized detection to characterize bosonic environments at the quantum level.
Exchange-mediated magnetic blue-shift of the band-gap energy in the antiferromagnetic semiconductor MnTe
Authors: Bossini D , Terschanski M , Mertens F , Springholz G , Bonanni A , Uhrig G S , Cinchetti M
Published: June 2020

In magnetic semiconductors the optical spectrum and, in particular, the absorption edge representing the band-gap are strongly affected by the onset of the magnetic order. This contribution to the band-gap energy has hitherto been described theoretically in terms of a Heisenberg Hamiltonian, in which a delocalized conduction carrier is coupled to the localized magnetic moments by the exchange interaction. Such models, however, do not take into account the strong correlations displayed in a wide variety of magnetic semiconductors, which are responsible for the formation of the local moments. In particular, the itinerant carrier itself contributes to the spin moment. Here, we overcome this simplification in a combined experimental and theoretical study of the antiferromagnetic semiconductor α-MnTe. First, we present a spectroscopic optical investigation as a function of temperature, from which we extract the magnetic contribution to the blue-shift of the band-gap. Second, we formulate a minimal model based on a Hubbard–Kondo Hamiltonian. In this model, the itinerant charge is one of the electrons forming the localized magnetic moment, which properly captures correlation effects in the material. Our theory reproduces the experimental findings with excellent quantitative agreement, demonstrating that the magnetic contribution to the band-gap energy of α-MnTe is mediated solely by the exchange interaction. These results describe an intrinsic property of the material, independent of the thickness, substrate and capping layer of the specimen. One of the key findings of the model is that the basic effect, namely a blue-shift of the band-gap due to the establishment of the magnetic order, is a general phenomenon in charge-transfer insulators. The identification of the relevant magnetic interaction discloses the possibility to exploit the effect here discussed to induce a novel regime of coherent spin dynamics, in which spin oscillations on a characteristic time-scale of 100 fs are triggered and are intrinsically coupled to charges.
Formation region of emitted α and heavier particles inside radioactive nuclei
Authors: Seif W. M. , Abdelhady A. M. H.
Published: June 2020

We investigate the formation distance (R
0) from the center of the radioactive parent nucleus at which the emitted cluster is most probably formed. The calculations are performed microscopically starting with the solution to the time-independent Schrödinger wave equation for the cluster-core system, using nuclear potentials based on the Skyrme-SLy4 nucleon-nucleon interactions and folding Coulomb potential, to determine the incident and transmitted wave functions of the system. Our results show that the emitted cluster is mostly formed in the pre-surface region of the nucleus, under the effect of Pauli blocking from the saturated core density. The deeper α-formation distance inside the nucleus allows less preformation probability and indicates a more stable nucleus for a longer half-life. Furthermore, the α-particle tends to be formed at a slightly deeper region inside the nuclei, with larger isospin asymmetry, and in the closed shell nuclei. Regarding the heavy clusters, we observed that the formation distance of the emitted clusters heavier than α-particle increased via increasing the isospin asymmetry of the formed cluster rather than by increasing its mass number. The partial half-life of a certain cluster-decay mode increased with increase of either the mass number or the isospin asymmetry of the emitted cluster.
Nonlinear chiral molecular photonics using twisted light: hyper-Rayleigh and hyper-Raman optical activity
Authors: Forbes Kayn A
Published: June 2020

Chiroptical and optical activity effects involve differential interactions between matter and light. Generally this involves chiral molecules absorbing or scattering right- and left-handed circularly polarized photons at different rates due to the chiroptical interplay of molecular and optical chirality. Laser light which propagates with a helical phase and twisted wavefront possesses optical orbital angular momentum. These optical vortices can twist either clockwise or anticlockwise, and as such they exhibit an optical handedness or chirality completely distinct from that of circular polarization. It has recently been established that the linear optical effects of single-photon absorption and scattering can exhibit optical activity and chiroptical interactions with respect to the optical vortex handedness. Here a fundamental mechanism of optical activity for twisted light is exhibited in nonlinear processes, with specific emphasis on hyper-Rayleigh and hyper-Raman scattering. In comparison to unstructured or plane-wave light, it is shown that using twisted photons produces novel scattering mechanisms dependent on parameters unique to optical vortex beams. Specifically, the scattered intensity for both hyper-Rayleigh and hyper-Raman optical activity is dependent on the sign and magnitude of the OAM of the incident twisted photons, as well as the transverse position of the chiral scatterer. Moreover, symmetry analysis reveals that, unlike the recently discovered linear optical activity effects with optical vortices, nonlinear scattering of twisted light by chiral molecules leads to a modification of scattering through uniquely weighted individual hyperpolarizability contributions.
Plans for African Space Agency jeopardized by slow progress
Authors: Makoni Munyaradzi
Published: June 2020

Progress establishing a space agency for the African Union (AU) has come to a standstill over a lack of funding and questions about how it will operate.
Freeman Dyson: unorthodox to the end
Authors: Johnston Hamish
Published: June 2020

The mathematical physicist Freeman Dyson was famed for his visionary ideas that stretched far beyond pure science. Hamish Johnston looks at the life of a scientist who was never afraid to speak his mind
COVID-19: the fallout
Authors: Durrani Matin
Published: June 2020

Like everyone else around the world, physicists have been caught up in the COVID-19 outbreak, which was declared a pandemic by the World Health Organization last month.
What would you do?
Authors: Crease Robert P
Published: June 2020

Robert P Crease examines his responsibility for not exploring one physicist’s treatment of women
Life in a carbon-neutral world
Authors: Ravilious Kate
Published: June 2020

Increasing numbers of cities and countries around the globe are pledging to become net carbon neutral within the next few decades. But what will day-to-day life look like in a “net-zero” world? Kate Ravilious looks at the changes that society will need to make
Going with the flow
Authors: McEntee Joe
Published: June 2020

Early-career industry physicist Aidan White tells Joe McEntee about his work as a project engineer at TÜV SÜD National Engineering Laboratory, the UK’s designated institute for flow and density measurement
That's a wrap!
Authors: Durrani Matin
Published: June 2020

“When we should all be trying to reduce the amount of waste plastic dumped into the ecosphere, I would really like Physics World not to be delivered enveloped in a plastic shroud.
This is the critical point
Authors: Crease Robert P
Published: June 2020

Having written the Critical Point column in Physics World for 20 years, Robert P Crease still worries that physicists don't realize why the humanities are so important
Complex crystals
Authors: Budden John
Published: June 2020

In response to Peter Hannaford and Krzysztof Sacha’s feature “Time crystals enter the real world of condensed matter” (March 2020) in which the authors look at how exotic time crystals – which break time-translational symmetry rather than spatial symmetry – could have applications in condensed-matter devices.
The search for the missing plastic
Authors: Stephens Marric
Published: June 2020

There is a huge amount of plastic waste polluting our oceans – but we don’t know where it is. Marric Stephens investigates what scientists are doing to find the missing plastic
Money from maths
Authors: Appell David
Published: June 2020

Meet Jim Simons – mathematician, “quant”, billionaire, philanthropist and a unique kind of genius. He is also the subject of a new book, The Man Who Solved the Market: How Jim Simons Launched the Quant Revolution by Gregory Zuckerman.
Quantum inheritance and the ongoing quest for meaning
Authors: Ball Philip
Published: June 2020

Collections of essays often have an uncertain status. In the absence of any overarching message, they stand or fall on the quality of the writing and the author’s ability to offer regular jolts of insight and entertainment. When (full disclosure) David Kaiser told me last summer that he was putting the finishing touches to his anthology Quantum Legacies: Dispatches from an Uncertain World, I had little doubt that it would meet the challenge.
Ag nanoparticle decorated Sb2O3 thin film: synthesis, characterizations and application
Authors: Divya K V , Abraham K E
Published: June 2020

The property modifications in a thin film when its surface undergoes a nanoparticle decoration process in addition to its surface nanostructuring are investigated this paper. In specific, it describes the property modifications of antimony trioxide and its annealed variant, when their surface is decorated with Ag nanoparticles. Along with the modifications brought to the thin films, the morphology variations or agglomeration effects happening to Ag nanoparticles through/after this decoration process is also discussed here. We observe a mutual tuning of morphology as well as properties of thin film and nanoparticles. A fractal like cluster formation of Ag nanoparticle on the surface of nanostructured Sb2O3 thin film was witnessed. Whereas on the surfaces of Sb2O3 (annealed) thin film and glass plate, clustering of Ag nanoparticle is found to be different. On annealed Sb2O3 thin film surface, instead of forming fractal clusters most of the Ag nanoparticles fill in the voids between the thorns like structure of the film. The surface modification highly influences the optical absorption as well as the hydrophilicity of antimony trioxide samples. Due to the introduction of Ag nanoparticle, the absorption of Sb2O3 thin film in the visible region increased. All the synthesized films have roughness coefficient >1 and all are hydrophilic in nature. Nano structured Sb2O3 thin film is extremely hydrophilic and they become hydrophilic due to the introduction of Ag nanoparticle. The filling of Ag nanoparticles in the voids between the thorn structures might have prevented the water droplet penetration into these voids. Consequently, a partial wetting occurs on the film surface. High SERS efficiency factor (EF) and good reproducibility of Ag/Sb2O3/Glass make it a good candidate for SERS application.
The Hec1/Ndc80 tail domain is required for force generation at kinetochores, but is dispensable for kinetochore–microtubule attachment formation and Ska complex recruitment
Authors: Wimbish Robert T. , DeLuca Keith F. , Mick Jeanne E. , Himes Jack , Jiménez-Sánchez Ignacio , Jeyaprakash A. Arockia , DeLuca Jennifer G.
Published: June 2020

This study demonstrates that the Ska complex and the Hec1 tail domain contribute to kinetochore–microtubule attachment regulation independently. The Hec1 tail is shown to be dispensable for Ska complex recruitment to kinetochores and for formation of kinetochore–microtubule attachments, but required for wild-type force generation at kinetochores.
Racial Capitalism Within Public Health—How Occupational Settings Drive COVID-19 Disparities
Authors: McClure Elizabeth S , Vasudevan Pavithra , Bailey Zinzi , Patel Snehal , Robinson Whitney R
Published: June 2020

Epidemiology of the US coronavirus disease 2019 (COVID-19) outbreak focuses on individuals’ biology and behaviors, despite centrality of occupational environments in the viral spread. This demonstrates collusion between epidemiology and racial capitalism because it obscures structural influences, absolving industries of responsibility for worker safety. In an empirical example, we analyzed economic implications of race-based metrics widely used in occupational epidemiology. In the United States, White adults have better average lung function and worse hearing than Black adults. Impaired lung function and impaired hearing are both criteria for workers’ compensation claims, which are ultimately paid by industry. Compensation for respiratory injury is determined using a race-specific algorithm. For hearing, there is no race adjustment. Selective use of race-specific algorithms for workers’ compensation reduces industries’ liability for worker health, illustrating racial capitalism operating within public health. Widespread and unexamined belief in inherent physiological inferiority of Black Americans perpetuates systems that limit industry payouts for workplace injuries. We see a parallel in the epidemiology of COVID-19 disparities. We tell stories of industries implicated in the outbreak and review how they exemplify racial capitalism. We call on public health professionals to critically evaluate who is served and neglected by data analysis and to center structural determinants of health in etiological evaluation.
Edge effects and mating patterns in a bumblebee-pollinated plant
Authors: Christopher Dorothy A , Mitchell Randall J , Trapnell Dorset W , Smallwood Patrick A , Semski Wendy R , Karron Jeffrey D
Published: June 2020

Researchers have long assumed that plant spatial location influences plant reproductive success and pollinator foraging behaviour. For example, many flowering plant populations have small, linear or irregular shapes that increase the proportion of plants on the edge, which may reduce mating opportunities through both male and female function. Additionally, plants that rely on pollinators may be particularly vulnerable to edge effects if those pollinators exhibit restricted foraging and pollen carryover is limited. To explore the effects of spatial location (edge vs. interior) on siring success, seed production, pollinator foraging patterns and pollen-mediated gene dispersal, we established a square experimental array of 49 Mimulus ringens (monkeyflower) plants. We observed foraging patterns of pollinating bumblebees and used paternity analysis to quantify male and female reproductive success and mate diversity for plants on the edge versus interior. We found no significant differences between edge and interior plants in the number of seeds sired, mothered or the number of sires per fruit. However, we found strong differences in pollinator behaviour based on plant location, including 15 % lower per flower visitation rates and substantially longer interplant moves for edge plants. This translated into 40 % greater pollen-mediated gene dispersal for edge than for interior plants. Overall, our results suggest that edge effects are not as strong as is commonly assumed, and that different plant reproduction parameters respond to spatial location independently.
Evaluating Postoperative Outcomes of Patients Undergoing Elective Procedures in an Ambulatory Surgery Center During the COVID-19 Pandemic
Authors: Couto Rafael A , Wiener Thomas C , Adams William P
Published: June 2020

Background

Despite the rapid increase in the number of publications pertaining to COVID-19, there is a lack of data examining patient outcomes following elective procedures performed during this pandemic.

Objectives

The purpose of this investigation was to examine the postoperative outcomes of patients who underwent elective procedures in an ambulatory surgery center during the COVID-19 pandemic, and to share the preoperative screening and patient selection protocol implemented in our center.

Methods

Elective procedures performed in an ambulatory surgery center between March 1, 2020 and April 16, 2020 were retrospectively reviewed. The primary outcomes were occurrence of COVID-19–related postoperative complications. These complications include pneumonia, stroke, myocardial infarction, and clotting disorders. The predictive variables analyzed in this study were age, American Society of Anesthesiologists score, specialty conducting the procedure, operating time, and the type of plastic and reconstructive surgery procedure being performed.

Results

A total of 300 consecutive electives cases were included in the study. The most common procedures were pain management (43.0%), gastrointestinal (26.0%), aesthetic (14.0%), orthopedic (10.3%), reconstructive (4.0%), otorhinolaryngology (2.0%), and gynecology (0.67%). The median age of the cohort was 54.6 years (range, 1-90 years) and the median procedure time was 47 minutes (range, 11-304 minutes). COVID-19–related symptoms or complications following the procedures were not observed in any of the patients or in the healthcare care personnel.

Conclusions

In this cohort of 300 elective cases, we found no patients with COVID-19–related symptoms postoperatively. This suggests that with proper preoperative screening and patient selection, elective procedures can be safely performed in an ambulatory surgery center during this pandemic.

Level of Evidence: 4
Biomedical named entity recognition and linking datasets: survey and our recent development
Authors: Huang Ming-Siang , Lai Po-Ting , Lin Pei-Yen , You Yu-Ting , Tsai Richard Tzong-Han , Hsu Wen-Lian
Published: June 2020

Natural language processing (NLP) is widely applied in biological domains to retrieve information from publications. Systems to address numerous applications exist, such as biomedical named entity recognition (BNER), named entity normalization (NEN) and protein–protein interaction extraction (PPIE). High-quality datasets can assist the development of robust and reliable systems; however, due to the endless applications and evolving techniques, the annotations of benchmark datasets may become outdated and inappropriate. In this study, we first review commonlyused BNER datasets and their potential annotation problems such as inconsistency and low portability. Then, we introduce a revised version of the JNLPBA dataset that solves potential problems in the original and use state-of-the-art named entity recognition systems to evaluate its portability to different kinds of biomedical literature, including protein–protein interaction and biology events. Lastly, we introduce an ensembled biomedical entity dataset (EBED) by extending the revised JNLPBA dataset with PubMed Central full-text paragraphs, figure captions and patent abstracts. This EBED is a multi-task dataset that covers annotations including gene, disease and chemical entities. In total, it contains 85000 entity mentions, 25000 entity mentions with database identifiers and 5000 attribute tags. To demonstrate the usage of the EBED, we review the BNER track from the AI CUP Biomedical Paper Analysis challenge. Availability: The revised JNLPBA dataset is available at https://iasl-btm.iis.sinica.edu.tw/BNER/Content/Re vised_JNLPBA.zip. The EBED dataset is available at https://iasl-btm.iis.sinica.edu.tw/BNER/Content/AICUP _EBED_dataset.rar. Contact: Email: thtsai@g.ncu.edu.tw, Tel. 886-3-4227151 ext. 35203, Fax: 886-3-422-2681 Email: hsu@iis.sinica.edu.tw, Tel. 886-2-2788-3799 ext. 2211, Fax: 886-2-2782-4814 Supplementary information: Supplementary data are available at Briefings in Bioinformatics online.