bluuebunny/crossref_metadata_2025 huggingface dataset:
Colour image encryption based on logistic mapping and double random‐phase encoding
Authors: Huang Huiqing , Yang Shouzhi
Published: December 2016

In this study, the authors propose a novel method to encrypt a colour image by use of Logistic mapping and double random‐phase encoding. Firstly, use Logistic mapping to diffuse the colour image, then the red, green and blue components of the result are scrambled by replacement matrices generated by Logistic mapping. Secondly, by utilising double random‐phase encoding to encrypt the three scrambled images into one encrypted image. Experiment results reveal the fact that the proposed method not only can achieve good encryption result, but also that the key space is large enough to resist against common attack.
Optical and adsorption properties of mesoporous SiO2/Zn2SiO4:Eu3+ hollow nanospheres
Authors: Dai Peng , Sun You‐Quan , Bao Zhi‐Wei , Zhu Jin , Wu Ming‐Zai
Published: December 2016

Mesoporous SiO2/Zn2SiO4:Eu3+ hollow nanospheres were successfully synthesised via the combination of layer‐by‐layer and combustion technique. The structures and morphologies of as‐obtained SiO2/Zn2SiO4:Eu3+ nanospheres were investigated using X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N2 adsorption–desorption isotherms techniques. SiO2/Zn2SiO4:Eu3+ nanospheres can be tested as adsorbents to remove heavy metal ions, which showed good adsorption capacity and selectively adsorption especially for Pb2+ and Cu2+ than Cd2+. The optical properties studies of as‐synthesised samples showed that mesoporous SiO2/Zn2SiO4:Eu3+ hollow nanospheres had strong red emission around 618 nm, and the optimal loading dosage of Eu3+ was determined. Moreover, the mesoporous SiO2/Zn2SiO4:Eu3+ hollow nanospheres could offer cell optical imaging by conventional fluorescence with 543 nm excitation.
Atmospheric tides in Earth-like planets
Authors: Auclair-Desrotour P. , Laskar J. , Mathis S.
Published: December 2016

Context.Atmospheric tides can strongly affect the rotational dynamics of planets. In the family of Earth-like planets, which includes Venus, this physical mechanism coupled with solid tides makes the angular velocity evolve over long timescales and determines the equilibrium configurations of their spin.

Aims.Unlike the solid core, the atmosphere of a planet is subject to both tidal gravitational potential and insolation flux coming from the star. The complex response of the gas is intrinsically linked to its physical properties. This dependence has to be characterized and quantified for application to the wide variety of extrasolar planetary systems.

Methods.We develop a theoretical global model where radiative losses, which are predominant in slowly rotating atmospheres, are taken into account. We analytically compute the perturbation of pressure, density, temperature, and velocity field caused by a thermogravitational tidal perturbation. From these quantities, we deduce the expressions of atmospheric Love numbers and tidal torque exerted on the fluid shell by the star. The equations are written for the general case of a thick envelope and the simplified one of a thin isothermal atmosphere.

Results.The dynamics of atmospheric tides depends on the frequency regime of the tidal perturbation: the thermal regime near synchronization and the dynamical regime characterizing fast-rotating planets. Gravitational and thermal perturbations imply different responses of the fluid, i.e. gravitational tides and thermal tides, which are clearly identified. The dependence of the torque on the tidal frequency is quantified using the analytic expressions of the model for Earth-like and Venus-like exoplanets and is in good agreement with the results given by global climate models (GCM) simulations.Introducing dissipative processes such as radiation regularizes the tidal response of the atmosphere, otherwise it is singular at synchronization.

Conclusions.We demonstrate the important role played by the physical and dynamical properties of a super-Earth atmosphere (e.g. Coriolis, stratification, basic pressure, density, temperature, radiative emission) in its response to a tidal perturbation.  We point out the key parameters defining tidal regimes (e.g. inertia, Brunt-Väisälä, radiative frequencies, tidal frequency) and characterize the behaviour of the fluid shell in the dissipative regime, which cannot be studied without considering the radiative losses.
Infrared laser spectroscopy of the n-propyl and i-propyl radicals: Stretch-bend Fermi coupling in the alkyl CH stretch region
Authors: Franke Peter R. , Tabor Daniel P. , Moradi Christopher P. , Douberly Gary E. , Agarwal Jay , Schaefer Henry F. , Sibert Edwin L.
Published: December 2016

The n-propyl and i-propyl radicals were generated in the gas phase via pyrolysis of n-butyl nitrite [CH3(CH2)3ONO] and i-butyl nitrite [(CH3)2CHCH2ONO], respectively. Nascent radicals were promptly solvated by a beam of He nanodroplets, and the infrared spectra of the radicals were recorded in the CH stretching region. Several previously unreported bands are observed between 2800 and 3150 cm−1. The CH stretching modes observed above 3000 cm−1 are in excellent agreement with CCSD(T) anharmonic frequencies computed using second-order vibrational perturbation theory. However, between 2800 and 3000 cm−1, the spectra of n- and i-propyl radicals become congested and difficult to assign due to the presence of multiple anharmonic resonance polyads. To model the spectrally congested region, Fermi and Darling-Dennison resonances are treated explicitly using “dressed” Hamiltonians and CCSD(T) quartic force fields in the normal mode representation, and the agreement with experiment is less than satisfactory. Computations employing local mode effective Hamiltonians reveal the origin of the spectral congestion to be strong coupling between the high frequency CH stretching modes and the lower frequency CHn bending/scissoring motions. The most significant coupling is between stretches and bends localized on the same CH2/CH3 group. Spectral simulations using the local mode approach are in excellent agreement with experiment.
High order harmonic generation from SF6: Deconvolution of macroscopic effects
Authors: Wilson B. P. , Fulfer K. D. , Mondal S. , Ren X. , Tross J. , Poliakoff E. D. , Jose J. , Le Anh-Thu , Lucchese R. R. , Trallero-Herrero C.
Published: December 2016

We measure high order harmonics from the molecule SF6 over a large range of phase matching conditions and observe several features in the harmonics that are largely independent of such macroscopic conditions. The experimental data are then compared to the quantitative rescattering theory for the generation of harmonics from three orbitals. With this comparison, we are able to assign spectroscopic features in the harmonics to contributions from 1t1g (HOMO) and 5t1u (HOMO-1) orbitals.
Convergence of coupled cluster perturbation theory
Authors: Eriksen Janus J. , Kristensen Kasper , Matthews Devin A. , Jørgensen Poul , Olsen Jeppe
Published: December 2016

The convergence of a recently proposed coupled cluster (CC) family of perturbation series [J. J. Eriksen et al., J. Chem. Phys. 140, 064108 (2014)], in which the energetic difference between two CC models—a low-level parent and a high-level target model—is expanded in orders of the Møller-Plesset (MP) fluctuation potential, is investigated for four prototypical closed-shell systems (Ne, singlet CH2, distorted HF, and F–) in standard and augmented basis sets. In these investigations, energy corrections of the various series have been calculated to high orders and their convergence radii have been determined by probing for possible front- and back-door intruder states, the existence of which would make the series divergent. In summary, we conclude how it is primarily the choice of the target state, and not the choice of the parent state, which ultimately governs the convergence behavior of a given series. For example, restricting the target state to, say, triple or quadruple excitations might remove intruders present in series which target the full configuration interaction limit, such as the standard MP series. Furthermore, we find that whereas a CC perturbation series might converge within standard correlation consistent basis sets, it may start to diverge whenever these become augmented by diffuse functions, similar to the MP case. However, unlike for the MP case, such potential divergences are not found to invalidate the practical use of the low-order corrections of the CC perturbation series.
Junctionless nanowire TFET with built-in N-P-N bipolar action: Physics and operational principle
Authors: Rahimian Morteza , Fathipour Morteza
Published: December 2016

In this paper, we present a novel junctionless nanowire tunneling FET (JN-TFET) in which the source region is divided into an n+ as well as a p+ type region. We will show that this structure can provide a built-in n-p-n bipolar junction transistor (BJT) action in the on state of the device. In this regime, tunneling of electrons from the source valence band into the channel conduction band enhances the hole concentration in the p+ source region. Also, the potential in this region is increased, which drives a built-in BJT transistor by forward biasing the base-emitter junction. Thus, the BJT current adds up to the normal tunneling current in the JN-TFET. Owing to the sharp switching of the JN-TFET and the high BJT current gain, the overall performance of the device, herein called “BJN-TFET,” is improved. On-state currents as high as 2.17 × 10−6 A/μm and subthreshold swings as low as ∼50 mV/dec at VDS = 1 V are achieved.
Germanium-on-silicon nitride waveguides for mid-infrared integrated photonics
Authors: Li Wei , Anantha P. , Bao Shuyu , Lee Kwang Hong , Guo Xin , Hu Ting , Zhang Lin , Wang Hong , Soref Richard , Tan Chuan Seng
Published: December 2016

A germanium-based platform with a large core-clad index contrast, germanium-on-silicon nitride waveguide, is demonstrated at mid-infrared wavelength. Simulations are performed to verify the feasibility of this structure. This structure is realized by first bonding a silicon-nitride-deposited germanium-on-silicon donor wafer onto a silicon substrate wafer, followed by the layer transfer approach to obtain germanium-on-silicon nitride structure, which is scalable to all wafer sizes. The misfit dislocations which initially form along the interface between germanium/silicon can be removed by chemical mechanical polishing after layer transfer process resulting in a high-quality germanium layer. At the mid-infrared wavelength of 3.8 μm, the germanium-on-silicon nitride waveguide has a propagation loss of 3.35 ± 0.5 dB/cm and a bend loss of 0.14 ± 0.01 dB/bend for a radius of 5 μm for the transverse-electric mode.
Use of otolith chemistry and acoustic telemetry to elucidate migratory contingents in barramundi Lates calcarifer
Authors: Crook D. A. , Buckle D. J. , Allsop Q. , Baldwin W. , Saunders T. M. , Kyne P. M. , Woodhead J. D. , Maas Roland , Roberts Brien , Douglas M. M.
Published: December 2016

Migration is a fundamental aspect of the life history of many fish and must be well understood for targeted conservation and management. We used acoustic telemetry and otolith 87Sr/86Sr analysis, in conjunction with annual ageing, to study intraspecific variation in barramundi Lates calcarifer migration in the Northern Territory, Australia. Acoustic transmitters were implanted into 25 barramundi (420–1010-mm total length (TL); median 510mm TL) from freshwater reaches of the South Alligator River and their movements tracked over >2 years. 87Sr/86Sr transect analysis was also conducted on otoliths of 67 barramundi from the Daly, Mary, South Alligator and Roper rivers. Acoustic telemetry showed that most fish remained in fresh water across wet and dry seasons. Higher rates of movement occurred during the wet season and a minority of fish moved into the estuary during high flows. Otolith chemistry analyses revealed high diversity in salinity histories among individuals. We integrated the telemetry and otolith chemistry data to examine migration as a function of the stage of sexual development, and have proposed a revised life history model that identifies three migratory contingents. We conclude that anthropogenic disturbance, including modified river hydrology, has the potential to alter the frequency of life history contingents in barramundi populations.
Soil organic carbon losses by water erosion in a Mediterranean watershed
Authors: Cilek Ahmet
Published: December 2016

Soil organic carbon (SOC) is one of the primary elements required in the functioning of ecosystems. Soil erosion, a major mechanism of land degradation, removes SOC and transfers it to the hydrosphere or the atmosphere, thereby affecting key ecosystem functions and services. The Mediterranean region is highly susceptible to land degradation because of erosion due to heavy rains following long, dry, hot summers. Although the Mediterranean landscape typically has a high altitude and incline, the soil is brittle and soft and is easily washed away by rain. Thus, vast regions in Turkey have been afflicted by this type of soil degradation. This study aimed to (1) estimate the temporal distribution of water erosion in the Seyhan River Basin, (2) assess the spatial distribution of SOC and (3) estimate the depletion of SOC through soil erosion using the Pan-European Soil Erosion Risk Assessment model, a physically based, regionally scaled soil erosion model.
The annual amount of soil eroded from the Seyhan River Basin is estimated to be 7.8million tonnes per hectare (tha–1year–1). The amount of fertile soil loss from agricultural areas is ~1.2million tonnes per year. The maximum amount of soil erosion occurs in maintenance scrubland and degraded forest areas, contributing to 68% of erosion, followed by that in agricultural land, contributing to 27% of erosion, with the remaining in forests and urban areas.
Post-fire dispersal characteristics of charcoal particles in the Daxing'an Mountains of north-east China and their implications for reconstructing past fire activities
Authors: Li Yiyin , Xu Xin , Zhao Pengfei
Published: December 2016

A wildfire with many ignition points took place in the Daxing’an Mountains of north-east China in June 2010. After the fire, moss polsters and particle traps were collected from burnt and unburnt areas a few kilometres away from four ignition points. Charcoal extracted from the samples was divided into macroscopic charcoal >125 μm and microscopic charcoal <125 μm. Our results showed that the average amount of charcoal deposited in the burnt areas was statistically greater than the amount deposited in unburnt areas. The microscopic charcoal concentration inside the burnt areas rose as the size of the burnt area increased. However, the sampling points within the largest burnt area did not have the highest macroscopic charcoal concentration. We found that only limited amounts of charcoal were transported over a long distance and that the primary charcoal produced during or shortly after a fire event was much more abundant than the secondary charcoal produced during the non-fire period. This suggested that primary charcoal is the dominant signal in charcoal records, and that the charcoal Z-score values inside the burnt areas were clearly higher than the surroundings. Our observations indicate that multiple-size charcoal records may be a robust tool for reconstructing fire histories.
Perspectives on the role of mobility, behavior, and time scales in the spread of diseases
Authors: Castillo-Chavez Carlos , Bichara Derdei , Morin Benjamin R.
Published: December 2016

The dynamics, control, and evolution of communicable and vector-borne diseases are intimately connected to the joint dynamics of epidemiological, behavioral, and mobility processes that operate across multiple spatial, temporal, and organizational scales. The identification of a theoretical explanatory framework that accounts for the pattern regularity exhibited by a large number of host–parasite systems, including those sustained by host–vector epidemiological dynamics, is but one of the challenges facing the coevolving fields of computational, evolutionary, and theoretical epidemiology. Host–parasite epidemiological patterns, including epidemic outbreaks and endemic recurrent dynamics, are characteristic to well-identified regions of the world; the result of processes and constraints such as strain competition, host and vector mobility, and population structure operating over multiple scales in response to recurrent disturbances (like El Niño) and climatological and environmental perturbations over thousands of years. It is therefore important to identify and quantify the processes responsible for observed epidemiological macroscopic patterns: the result of individual interactions in changing social and ecological landscapes. In this perspective, we touch on some of the issues calling for the identification of an encompassing theoretical explanatory framework by identifying some of the limitations of existing theory, in the context of particular epidemiological systems. Fostering the reenergizing of research that aims at disentangling the role of epidemiological and socioeconomic forces on disease dynamics, better understood as complex adaptive systems, is a key aim of this perspective.
Reducing future fears by suppressing the brain mechanisms underlying episodic simulation
Authors: Benoit Roland G. , Davies Daniel J. , Anderson Michael C.
Published: December 2016

Significance

Humans possess the remarkable ability to recombine details of divergent memories into imaginings of future events. Such imaginings are useful, for example, because they foster planning and motivate farsighted decisions. Importantly, recurrently imagining feared situations can also undermine our well-being and may even contribute to the development of anxiety. Here, we demonstrate that fearful imaginings about the future can be inhibited by neural mechanisms that help to suppress the past. Importantly, suppression reduces later apprehensiveness about the feared events, a benefit that was diminished in individuals with greater trait anxiety. This pattern suggests that the observed inhibition mechanism serves to control people’s future fears and its disruption may foster psychological disorders characterized by intrusive prospective thoughts.
Twist of generalized skyrmions and spin vortices in a polariton superfluid
Authors: Donati Stefano , Dominici Lorenzo , Dagvadorj Galbadrakh , Ballarini Dario , De Giorgi Milena , Bramati Alberto , Gigli Giuseppe , Rubo Yuri G. , Szymańska Marzena Hanna , Sanvitto Daniele
Published: December 2016

Significance

Spin vortices and skyrmions are topological states in exotic phases of matter such as superconductors and superfluids. In these complex states, the spin and orbital angular momentum are both quantized and mixed, resulting in variegated polarization textures. Here we create these composite states in a fluid made of light and matter quasi-particles, polaritons, and demonstrate their reshaping in ultrafast time scales. To describe these dynamics we propose the idea of generalized vortices, a fundamental concept in topology that can be relevant also for applications in the fields of quantum fluids, spintronics, and optical polarization shaping.
Conservation of coevolving protein interfaces bridges prokaryote–eukaryote homologies in the twilight zone
Authors: Rodriguez-Rivas Juan , Marsili Simone , Juan David , Valencia Alfonso
Published: December 2016

Significance

Interacting proteins tend to coevolve through interdependent changes at the interaction interface. This phenomenon leads to patterns of coordinated mutations that can be exploited to systematically predict contacts between interacting proteins in prokaryotes. We explore the hypothesis that coevolving contacts at protein interfaces are preferentially conserved through long evolutionary periods. We demonstrate that coevolving residues in prokaryotes identify interprotein contacts that are particularly well conserved in the corresponding structure of their eukaryotic homologues. Therefore, these contacts have likely been important to maintain protein–protein interactions during evolution. We show that this property can be used to reliably predict interacting residues between eukaryotic proteins with homologues in prokaryotes even if they are very distantly related in sequence.
Expressing generic and transitory opinions in Greek
Authors: Bimpikou Sofia
Published: December 2016

This paper investigates the semantics of the Greek subjective attitude verbs vrisko (‘find’) and theoro (‘consider’). I present data from Greek where both verbs embed small clauses including evaluative adjectives (‘tasty’, ‘attractive’) and I develop a tentative analysis for each verb following Sæbø’s (2009) account of find and Chierchia’s (1995) analysis for generic predicates. I propose that: a) vrisko is a stage-level subjective verb expressing transitory opinions about objects of evaluation as viewed within a particular experience situation; b) theoro is an individual-level subjective verb expressing generic opinions about objects of evaluation as realised across various experience situations. This approach explains the observed contrasts between the two verbs. Moreover, it shows that the individual- and stage- level distinction is manifested in attitude verbs and that language employs distinct verbs depending on how an object of evaluation is viewed by the relevant judge.
Simultaneous invariance of generalized spherical harmonics under the operations of two rotation groups
Authors: D’Heedene R. N.
Published: December 2016

A method is found for evaluating the coefficients of a sum of generalized spherical harmonics so that the sum will be simultaneously invariant under two rotation groups. The coefficients for a sum of ordinary spherical harmonics invariant under each individual group must first be known.