bluuebunny/crossref_metadata_2025 huggingface dataset:
Clustering-based computation of degradation rate for photovoltaic systems
Authors: Bhola Parveen , Bhardwaj Saurabh
Published: January 2019

For effective utilization of solar energy, performance monitoring of photovoltaic (PV) systems is required. Two important research goals are to maximize the power output from PV systems and further reduce the economic losses. This paper proposes a model using a clustering-based technique to evaluate the degradation of PV panels with different topologies. Here, the performance ratio (PR) of the PV panels is estimated without physical inspection on-site, making the proposed model beneficial for real-time estimation of the PR and in turn for more robust forecasting of the PV power output. The present work utilizes the segmental K-means clustering technique to obtain clusters of input meteorological data sharing similar features. Various forms of meteorological data, including temperature, relative humidity, wind speed, dew point, solar radiation, and sunshine hours, are given as the input, and solar power data are the output of the proposed model. The proposed model calculates the degradation in output solar power in terms of PR for panels with three different topologies, namely, amorphous silicon (a-Si), polycrystalline silicon (p-Si), and hetero-junction with an intrinsic thin layer (HIT), over a period of three years. The degradation rate produced by a-Si technology was lowest, and it was highest for HIT technology. The results obtained showed good agreement with the standard method used for performance evaluation in a similar earlier study. The proposed model has the advantage over other methods that real-time estimation is possible, as this method does not require physical inspection and imaging, which is essential in other techniques.
Non-self-adjoint operators with real spectra and extensions of quantum mechanics
Authors: Bebiano N. , da Providência J.
Published: January 2019

In this article, we review the quantum mechanical setting associated with a non-self-adjoint Hamiltonian with a real spectrum. The spectral properties of the Hamiltonian of a Swanson-like model are investigated. The eigenfunctions associated with the real simple eigenvalues are shown to form complete systems but not a (Riesz) basis, which gives rise to difficulties in the rigorous mathematical formulation of quantum mechanics. A new inner product, appropriate for the physical interpretation of the model, has been consistently introduced. The dynamics of the system is described. Some specificities of the theory of non-self-adjoint operators with implications in quantum mechanics are discussed.
Gamma-ray imaging with a time-modulated random coded aperture
Authors: Wang Dongming , Ruskov Ivan N. , Hu Huasi , Kopatch Yuri N. , Grozdanov Dimitar N. , Fedorov Nikita A. , Aliyev Fuad A.
Published: January 2019

In this article, we present a new industrial gamma-ray imaging system. This system takes advantage of a time-modulated random coded aperture (TMRCA). The gamma-ray detector coupled to the TMRCA can be position-sensitive or non-position-sensitive. The TMRCA imaging system could offer the ability to identify radioactive sources without losing spatial resolution. With a non-position-sensitive BGO detector, a prototype TMRCA imaging system was constructed. The prototype system was investigated with two gamma-ray sources (137Cs, 60Co) and a 238Pu–Be neutron source, which was placed in a paraffin moderator to produce an extended source. The experimental results suggest that the TMRCA imaging system offers the opportunity to achieve high spatial-energy resolution cost-effectively for high-energy gamma rays.
Evolution of phosphorus-vacancy clusters in epitaxial germanium
Authors: Vohra Anurag , Khanam Afrina , Slotte Jonatan , Makkonen Ilja , Pourtois Geoffrey , Loo Roger , Vandervorst Wilfried
Published: January 2019

The E centers (dopant-vacancy pairs) play a significant role in dopant deactivation in semiconductors. In order to gain insight into dopant-defect interactions during epitaxial growth of in situ phosphorus doped Ge, positron annihilation spectroscopy, which is sensitive to open-volume defects, was performed on Ge layers grown by chemical vapor deposition with different concentrations of phosphorus (∼1×1018–1×1020cm−3). Experimental results supported by first-principles calculations based on the two component density-functional theory gave evidence for the existence of mono-vacancies decorated by several phosphorus atoms as the dominant defect type in the epitaxial Ge. The concentration of vacancies increases with the amount of P-doping. The number of P atoms around the vacancy also increases, depending on the P concentration. The evolution of Pn–V clusters in Ge contributes significantly to the dopant deactivation.
Optical properties of semiconducting zigzag carbon nanotubes with and without defects
Authors: Mu Jinglin , Ma Yuchen , Liu Huichun , Zhang Tian , Zhuo Shuping
Published: January 2019

The excited states of a series of semiconducting zigzag (n, 0) tubes are studied using the GW method and the Bethe-Salpeter equation within the ab initio many-body perturbation theory. The optical variation rule of the excitation energy with the tube diameter exhibits a family pattern, which arises from the electronic structure of the pristine tube and depends on the value of n mod 3. The introduction of single vacancy and Stone-Wales defects with different orientations affords an effective route for modulating the band structures and optical spectra, resulting in the variation of the selection rules of the excitons and turning dipole-forbidden excitons into dipole-allowed ones. The new localized impurity states in defected tubes will provide additional optically allowed transitions and give rise to pronounced satellite red-shifted peaks. These findings provide inspiration for the tune of optical properties of carbon nanotubes in the future for applications in optoelectronics.
Manipulating photonic spin accumulation with a magnetic field
Authors: He Yu , Xie Linguo , Qiu Jiangdong , Luo Lan , Liu Xiong , Li Zhaoxue , Zhang Zhiyou , Du Jinglei
Published: January 2019

In this paper, we propose a simple and effective method to manipulate photonic spin accumulation with an applied magnetic field. When a linearly polarized Gaussian light beam is reflected from the prism-air interface at the Brewster angle, the magnitude and direction of the photonic spin accumulation can be flexibly modulated by adjusting the applied magnetic field. Importantly, the maximum displacement of photonic spin accumulation can reach about 39.14μm, which provides the opportunity to directly observe photonic spin accumulation without weak measurements. These findings may hold potential applications for manipulating and detecting the electron spin current, leading to the development of a new spintronic device.
High quantum efficiency mid-wavelength infrared type-II InAs/InAs1−xSbx superlattice photodiodes grown by metal-organic chemical vapor deposition
Authors: Wu Donghai , Durlin Quentin , Dehzangi Arash , Zhang Yiyun , Razeghi Manijeh
Published: January 2019

We report the growth and characterization of mid-wavelength infrared type-II InAs/InAs1−xSbx superlattice photodiodes on GaSb substrates grown by metal-organic chemical vapor deposition. At 150 K, the 50% cut-off wavelength is 5.0 μm, the dark current density is 3.3 × 10−4 A/cm2 under −20 mV bias, and the peak responsivity is 1.76 A/W corresponding to a quantum efficiency of 55% without anti-reflection coating. A specific detectivity of 1.2 × 1011 cm Hz1/2/W is achieved at 4.0 μm under −20 mV bias at 150 K.
Laser induced fluorescence studies on the distribution of surfactants during drop/interface coalescence
Authors: Dong Teng , Weheliye Weheliye Hashi , Angeli Panagiota
Published: January 2019

The spatiotemporal distribution of fluorescent surfactants on the merging interfaces during the coalescence of an aqueous drop with an organic/aqueous flat interface was studied experimentally with high-speed laser induced fluorescence. The aqueous phase was a 46% glycerol solution, while the organic phase was a 5 cSt silicone oil. A fluorescently tagged surfactant was used at a concentration of 0.001 mol/m3 in the aqueous phase. To vary the concentration of surfactants on the interfaces, the drop and the flat interface were left to stand for different times before the coalescence experiments (different interface ages). It was found that when a drop rested on the interface, the surfactants adsorbed on the interfaces were swept outwards by the draining liquid film between the drop and the flat interface and reached a peak value at 0.75Rh away from the centre of the film, where Rh is the horizontal drop radius. After the film rupture, the concentration of the surfactants at the tip of the meniscus increased. Once the film had retracted, the concentration of the surfactants peaked at the meniscus at the bottom of the drop. As the liquid in the drop started to merge with its homophase, the drop formed a cylinder from the upward capillary waves on the drop surface. The surfactant concentration was found to be low at the top of the liquid cylinder as the interface was stretched by the convergence of the capillary waves. Subsequently, the cylinder began to shrink and the top part of the drop acquired a high surfactant concentration.
A transient bond model for dynamic constraints in meso-scale coarse-grained systems
Authors: Uneyama Takashi
Published: January 2019

The dynamical properties of entangled polymers originate from the dynamic constraints due to the uncrossability between polymer chains. We propose a highly coarse-grained simulation model with transient bonds for such dynamically constrained systems. Based on the ideas of the responsive particle dynamics (RaPiD) model [P. Kindt and W. J. Briels, J. Chem. Phys. 127, 134901 (2007)] and the multi-chain slip-spring model [T. Uneyama and Y. Masubuchi, J. Chem. Phys. 137, 154902 (2012)], we construct the RaPiD type transient bond model as a coarse-grained slip-spring model. In our model, a polymer chain is expressed as a single particle, and particles are connected by transient bonds. The transient bonds modulate the dynamics of particles, but they do not affect static properties in equilibrium. We show the relation between parameters for the entangled polymer systems and those for the transient bond model. By performing simulations based on the transient bond model, we show how model parameters affect the linear viscoelastic behavior and the diffusion behavior. We also show that the viscoelastic behavior of entangled polymer systems can be well reproduced by the transient bond model.
Shockwave compression and dissociation of ammonia gas
Authors: Dattelbaum Dana M. , Lang John M. , Goodwin Peter M. , Gibson Lloyd L. , Gammel William P. , Coe Joshua D. , Ticknor Christopher , Leiding Jeffery A.
Published: January 2019

We performed a series of plate impact experiments on NH3 gas initially at room temperature and at a pressure of ∼100 psi. Shocked states were determined by optical velocimetry and the temperatures by optical pyrometry, yielding compression ratios of ∼5–10 and second shock temperatures in excess of 7500 K. A first-principles statistical mechanical (thermochemical) approach that included chemical dissociation yielded reasonable agreement with experimental results on the principal Hugoniot, even with interparticle interactions neglected. Theoretical analysis of reshocked states, which predicts a significant degree of chemical dissociation, showed reasonable agreement with experimental data for higher temperature shots; however, reshock calculations required the use of interaction potentials. We rationalize the very different shock temperatures obtained, relative to previous results for argon, in terms of atomic versus molecular heat capacities.
The electronic complexity of the ground-state of the FeMo cofactor of nitrogenase as relevant to quantum simulations
Authors: Li Zhendong , Li Junhao , Dattani Nikesh S. , Umrigar C. J. , Chan Garnet Kin-Lic
Published: January 2019

We report that a recent active space model of the nitrogenase FeMo cofactor, proposed in the context of simulations on quantum computers, is not representative of the electronic structure of the FeMo cofactor ground-state. A more representative model does not affect much certain resource estimates for a quantum computer such as the cost of a Trotter step, while strongly affecting others such as the cost of adiabatic state preparation. Thus, conclusions should not be drawn from the complexity of quantum or classical simulations of the electronic structure of this system in this active space. We provide a different model active space for the FeMo cofactor that contains the basic open-shell qualitative character, which may be useful as a benchmark system for making resource estimates for classical and quantum computers.
3D printed microfluidic viscometer based on the co-flowing stream
Authors: Hong Hyeonji , Song Jae Min , Yeom Eunseop
Published: January 2019

Considering the role of viscosity in the dynamics of physical, chemical, and biological systems, accurate measurement of viscosity is essential. Although many conventional viscometers have been widely used, these conventional viscometers suffer from some drawbacks. In this study, a three-dimensional (3D) printed microfluidic viscometer was proposed based on the estimation of the pressure between two fluids to easily measure viscosity with small samples. The 3D printed microfluidic viscometer can be fabricated through amine-epoxy bonding on 3D printed blocks. By separately delivering samples and reference fluids into two inlets, an interfacial line could be induced. Based on the relation between the pressure ratio and the width of the reference flow, the viscosity (μ) of the sample can be estimated by measuring the relative width of the reference flow. The relation between the pressure and interfacial width between test samples and reference flows in the 3D printed microfluidic viscometers was analyzed by experiment and simulation to determine the effects of the mesh-like pattern of the 3D printed viscometers on the pressure estimation. To validate the proposed method, the viscosity values of glycerol mixtures measured by the 3D printed viscometer were compared with those measured by a conventional viscometer. As an application of the 3D printed viscometer, the viscosity curves for blood samples collected from diabetic and non-diabetic patients depending on their shear rates were compared. As expected, a high blood viscosity in the diabetic group was observed. Based on the experimental demonstrations, the 3D printed viscometer has strong potential to develop portable viscometers that can be translated to commercial outcomes.
Total and partial electron impact ionization cross sections of fusion-relevant diatomic molecules
Authors: Huber Stefan E. , Mauracher Andreas , Süß Daniel , Sukuba Ivan , Urban Jan , Borodin Dmitry , Probst Michael
Published: January 2019

We report calculations of total (and absolute) electron-impact ionization cross sections (EICSs) for the fusion-relevant diatomic molecular species BeH, BeN, BeO, WH, WBe, WN, WO, O2, and N2 by means of the Deutsch-Märk and the binary-encounter-Bethe methods in the energy range from threshold to 10 keV. In addition, we discuss an empirical scheme to estimate partial cross sections from the total ones based on reaction energetics and empirical threshold laws and explore its accuracy by assessing available experimental data on total and partial EICSs. Finally, we also report parameters obtained by fitting the calculated cross sections to an expression commonly used in fusion edge plasma modeling.
Coalescence dynamics of unequal sized drops
Authors: Deka Hiranya , Biswas Gautam , Chakraborty Suman , Dalal Amaresh
Published: January 2019

In this study, coalescence dynamics of two unequal sized drops of the same liquid have been investigated using the coupled level set and volume of fluid method. A broad range of fluid properties is considered with two orders of magnitude variation of Ohnesorge numbers and Atwood number ranging between 0.01 and 0.9976. The pinch-off process and controlling parameters that lead to satellite generation have been investigated. The capillary waves are generated as a result of the sharp curvature produced near the contact region. Here we demonstrate that the capillary waves propagating along the interface of the lower drop can affect the eventual pinch-off of the satellite. The local curvature of the neck plays a crucial role in the pinch-off process. A sharper axial curvature of the neck increases the local capillary pressure which restricts the pinch-off. The critical diameter ratio above which a satellite pinches off during the coalescence of two free-falling drops increases with increasing relative strength of the viscous force and the gravity force. The critical ratio can be as low as 1.2 at a lower relative strength of the viscous and the gravity forces. The coalescence of two unequal sized drops may produce much smaller satellite drops, on account of coalescence in successive steps, with or without intermediate detachment.
Observation of the shallow 2Π1 state of NaH
Authors: Chu Chia-Ching , Huang Hsien-Yu , Lin Hsiang-Chin , Hsiao Yi-Hsiang , Whang Thou-Jen , Tsai Chin-Chun
Published: January 2019

The 2 1Π state of NaH has been observed up to the last bound vibrational level using pulsed optical-optical double resonance fluorescence depletion spectroscopy. A total of 20 rovibrational energy levels (v = 2–4 and J = 1–9) were assigned to this electronic state by means of comparing the successive rovibrational spectra to the eigenvalues of the ab initio potential energy curve. The decrease of background fluorescence near the atomic asymptotic limit Na(3d) + H(1s) is an indication of reaching the dissociation limit of the NaH 2 1Π state. Unobserved rovibrational levels (v = 0 and 1) are due to poor Franck-Condon overlap of 2 1Π ← A 1Σ+ transition within the accessible rovibrational levels of intermediate A 1Σ+ state of this work.
Single-step formation of Cr2N nanoparticles by pulsed laser irradiation
Authors: Gubert G. , Oliveira R. C. , Costa D. S. , Metzger G. K. , Mazzaro I. , Kellermann G. , Ribeiro E. , Varalda J. , Mosca D. H.
Published: January 2019

Chromium nitride nanoparticles with mean diameter distribution between 0.8 nm and 30 nm were produced by laser irradiation of a chromium target immersed in liquid nitrogen. Cr was directly converted to chromium nitride nanoparticles according to selected-area electron diffraction analyses using the transmission electron microscopy technique. Crystalline nanoparticles mostly consist of Cr2N, which is commonly reported together with the conversion of Cr2N to CrN and the mixture of chromium oxides. In addition, there is no evidence of oxidation by storage or photodegradation of the nanoparticles in isopropyl alcohol suspensions. The intensity profile of small-angle X-ray scattering indicates that the geometrical shape of the nanoparticles is not spherical but cylindrical with aspect ratio (height-to-radius) of 0.35–0.05. UV-Vis absorption spectroscopy reveals the presence of surface plasmon absorption at the ultraviolet region at wavelengths of 350, 372, and 397 nm. First-principles calculations of density of states, dielectric function, and optical conductivity performed within the theoretical framework of density functional theory for Cr2N with a hexagonal structure corroborate the formation of surface plasmons.
Dynamics and stability of a power-law film flowing down a slippery slope
Authors: Chakraborty Symphony , Sheu Tony Wen-Hann , Ghosh Sukhendu
Published: January 2019

A power-law fluid flowing down a slippery inclined plane under the action of gravity is deliberated in this research work. A Newtonian layer at a small strain rate is introduced to take care of the divergence of the viscosity at a zero strain rate. A low-dimensional two-equation model is formulated using a weighted-residual approach in terms of two coupled evolution equations for the film thickness h and a local velocity amplitude or the flow rate q within the framework of lubrication theory. Moreover, a long-wave instability is shown in detail. Linear stability analysis of the proposed two-equation model reveals good agreement with the spatial Orr-Sommerfeld analysis. The influence of a wall-slip on the primary instability has been found to be non-trivial. It has the stabilizing effect at larger values of the Reynolds number, whereas at the onset of the instability, the role is destabilizing which may be because of the increase in dynamic wave speed by the wall slip. Competing impressions of shear-thinning/shear-thickening and wall slip velocity on the primary instability are captured. The impact of slip velocity on the traveling-wave solutions is discussed using the bifurcation diagram. An increasing value of the slip shows a significant effect on the traveling wave and free surface amplitude. Slip velocity controls both the kinematic and dynamic waves of the system, and thus, it has the profound passive impact on the instability.
Single layer MoS2 nanoribbon field effect transistor
Authors: Kotekar-Patil D. , Deng J. , Wong S. L. , Lau Chit Siong , Goh Kuan Eng Johnson
Published: January 2019

We study field effect transistor characteristics in etched single layer MoS2 nanoribbon devices of width 50 nm with ohmic contacts. We employ a SF6 dry plasma process to etch MoS2 nanoribbons using low etching (RF) power allowing very good control over the etching rate. Transconductance measurements reveal a steep sub-threshold slope of 3.5 V/dec using a global backgate. Moreover, we measure a high current density of 38 μA/μm, resulting in a high on/off ratio of the order of 105. We observe mobility reaching as high as 50 cm2/V s with increasing source-drain bias.
Copper atomic contacts exposed to water molecules
Authors: Demir Firuz , Dean Kevin
Published: January 2019

Monatomic and molecular hydrogen and also oxygen, as well as water molecules and OH that are exposed to atomic copper in intimate contact, have been studied theoretically using computational methods. The authors optimized moderately large structures of Cu/H/Cu, Cu/HCuH/Cu, Cu/H2/Cu, Cu/H2O/Cu, Cu/OH/Cu, Cu/O/Cu, and Cu/O2/Cu and calculated appropriate values for conductance and inelastic tunneling spectroscopy (IETS) properties of the contact junctions, elucidating them as being a possible outcome resulting from the exposure of copper electrodes to the atomic/molecular contaminant species. Here we also demonstrate the IETS properties, by means of ab initio calculations, which can determine the form of the junction geometries. Furthermore, we identify the bonding geometries at the interfaces of the copper electrodes that directly give rise to the specific IETS signatures that have been observed in recent experiments. Based on low-bias conductance and IETS calculations, for the specific case of water exposure of copper electrodes, it was concluded that a single hydrogen or a single oxygen atom bridging the copper electrodes is not responsible for the high conductance peak measurements. Regarding Model 4, where an individual water molecule is considered to be the bridging constituent, our computational results suggest that it has a relatively low probability of being an appropriate candidate. Based upon current computational results, the two hydrogens in Model 3 appear to be in molecular form, although they still form a bond with the adjacent copper atoms. Comparing computational with experimental results indicates that Model 3 is in acceptable agreement with available data.
Effective n-type doping of Mg3Sb2 with group-3 elements
Authors: Gorai Prashun , Toberer Eric S. , Stevanović Vladan
Published: January 2019

The recent discovery of high thermoelectric performance in Mg3Sb2 has been critically enabled by the success in n-type doping of this material, which is achieved under Mg-rich growth conditions, typically with chalcogens (Se and Te) as extrinsic dopants. Using first-principles defect calculations, we previously predicted that higher electron concentrations (∼1020cm−3) can be achieved in Mg3Sb2 by doping with La instead of Se or Te [P. Gorai et al., J. Mater. Chem. A 6, 13806 (2018)]. Subsequent experiments [K. Imasato et al., J. Mater. Chem. A 6, 19941 (2018)] showed that free electron concentration in La-doped Mg3Sb2−xBix indeed exceeds those in the Te-doped material. Herein, we further investigate n-type doping of Mg3Sb2 and predict that, in addition to La, other group-3 elements (Sc and Y) are also effective as n-type dopants; Y is as good as La while Sc slightly less. Overall, we find that doping with any group-3 elements should lead to higher free electron concentrations than doping with chalcogens.
The origins of genomic imprinting in mammals
Authors: Edwards Carol A. , Takahashi Nozomi , Corish Jennifer A. , Ferguson-Smith Anne C.
Published: January 2019

Genomic imprinting is a process that causes genes to be expressed according to their parental origin. Imprinting appears to have evolved gradually in two of the three mammalian subclasses, with no imprinted genes yet identified in prototheria and only six found to be imprinted in marsupials to date. By interrogating the genomes of eutherian suborders, we determine that imprinting evolved at the majority of eutherian specific genes before the eutherian radiation. Theories considering the evolution of imprinting often relate to resource allocation and recently consider maternal–offspring interactions more generally, which, in marsupials, places a greater emphasis on lactation. In eutherians, the imprint memory is retained at least in part by zinc finger protein 57 (ZFP57), a Kruppel associated box (KRAB) zinc finger protein that binds specifically to methylated imprinting control regions. Some imprints are less dependent on ZFP57invivo and it may be no coincidence that these are the imprints that are found in marsupials. Because marsupials lack ZFP57, this suggests another more ancestral protein evolved to regulate imprints in non-eutherian subclasses, and contributes to imprinting control in eutherians. Hence, understanding the mechanisms acting at imprinting control regions across mammals has the potential to provide valuable insights into our understanding of the origins and evolution of genomic imprinting.
Assessing ecological infrastructure investments
Authors: Adamowicz Wiktor , Calderon-Etter Laura , Entem Alicia , Fenichel Eli P. , Hall Jefferson S. , Lloyd-Smith Patrick , Ogden Fred L. , Regina Jason A. , Rouhi Rad Mani , Stallard Robert F.
Published: January 2019

Conventional markets can underprovide ecosystem services. Deliberate creation of a market for ecosystem services [e.g., a payments for ecosystem services (PES) scheme] can close the gap. The new ecosystem service market alters behaviors and quantities of ecosystem service provided and reveals prices for the ecosystems service: a market-clearing equilibrium. Assessing the potential for PES programs, which often act as ecological infrastructure investment mechanisms, requires forecasting the market-clearing equilibrium. Forecasting the equilibrium is complicated, especially at relevant social and ecological scales. It requires greater disciplinary integration than valuing ecosystem services or computing the marginal cost of making a land-use change to produce a service. We conduct anex antebenefit–cost assessment and forecast market-clearing prices and quantities for ecological infrastructure investment contracts in the Panama Canal Watershed. The Panama Canal Authority could offer contracts to private farmers to change land use to increase dry-season water flow and reduce sedimentation. A feasible voluntary contracting system yields a small program of about 1,840 ha of land conversion in a 279,000-ha watershed and generates a 4.9 benefit–cost ratio. Physical and social constraints limit market supply and scalability. Service delays, caused by lags between the time payments must be made and the time services stemming from ecosystem change are realized, hinder program feasibility. Targeting opportunities raise the benefit–cost ratio but reduce the hectares likely to be converted. We compare and contrast our results with prior state-of-the-art assessments on this system.
Mission-driven research for stratospheric aerosol geoengineering
Authors: MacMartin Douglas G. , Kravitz Ben
Published: January 2019

The last decade has seen broad exploratory research into stratospheric aerosol (SA) geoengineering, motivated by concern that reducing greenhouse gas emissions may be insufficient to avoid significant impacts from climate change. Based on this research, it is plausible that a limited deployment of SA geoengineering, provided it is used in addition to cutting emissions, could reduce many climate risks for most people. However, “plausible” is an insufficient basis on which to support future decisions. Developing the necessary knowledge requires a transition toward mission-driven research that has the explicit goal of supporting informed decisions. We highlight two important observations that follow from considering such a comprehensive, prioritized natural-science research effort. First, while field experiments may eventually be needed to reduce some of the uncertainties, we expect that the next phase of research will continue to be primarily model-based, with one outcome being to assess and prioritize which uncertainties need to be reduced (and, as a corollary, which field experiments can reduce those uncertainties). Second, we anticipate a clear separation in scale and character between small-scale experimental research to resolve specific process uncertainties and global-scale activities. We argue that the latter, even if the radiative forcing is negligible, should more appropriately be considered after a decision regarding whether and how to deploy SA geoengineering, rather than within the scope of “research” activities.
Mesyl phosphoramidate antisense oligonucleotides as an alternative to phosphorothioates with improved biochemical and biological properties
Authors: Miroshnichenko S. K. , Patutina O. A. , Burakova E. A. , Chelobanov B. P. , Fokina A. A. , Vlassov V. V. , Altman S. , Zenkova M. A. , Stetsenko D. A.
Published: January 2019

Significance

Forty years of research have shown that antisense oligonucleotides have great potential to target mRNAs of disease-associated genes and noncoding RNAs. Among the vast number of oligonucleotide backbone modifications, phosphorothioate modification is the most widely used in research and the clinic. However, along with their merits are notable drawbacks of phosphorothioate oligonucleotides, including decreased binding affinity to RNA, reduced specificity, and increased toxicity. Here we report the synthesis and in vitro evaluation of the DNA analog mesyl phosphoramidate oligonucleotide. This oligonucleotide type recruits RNase H and shows significant advantages over phosphorothioate in RNA affinity, nuclease stability, and specificity in inhibiting key processes of carcinogenesis. Thus, mesyl phosphoramidate oligonucleotides may be an attractive alternative to phosphorothioates.
Leading a meaningful life at older ages and its relationship with social engagement, prosperity, health, biology, and time use
Authors: Steptoe Andrew , Fancourt Daisy
Published: January 2019

The sense that one is living a worthwhile and meaningful life is fundamental to human flourishing and subjective well-being. Here, we investigate the wider implications of feeling that the things one does in life are worthwhile with a sample of 7,304 men and women aged 50 and older (mean 67.2 y). We show that independently of age, sex, educational attainment, and socioeconomic status, higher worthwhile ratings are associated with stronger personal relationships (marriage/partnership, contact with friends), broader social engagement (involvement in civic society, cultural activity, volunteering), less loneliness, greater prosperity (wealth, income), better mental and physical health (self-rated health, depressive symptoms, chronic disease), less chronic pain, less disability, greater upper body strength, faster walking, less obesity and central adiposity, more favorable biomarker profiles (C-reactive protein, plasma fibrinogen, white blood cell count, vitamin D, high-density lipoprotein cholesterol), healthier lifestyles (physical activity, fruit and vegetable consumption, sleep quality, not smoking), more time spent in social activities and exercising, and less time spent alone or watching television. Longitudinally over a 4-y period, worthwhile ratings predict positive changes in social, economic, health, and behavioral outcomes independently of baseline levels. Sensitivity analyses indicate that these associations are not driven by factors such as prosperity or depressive symptoms, or by outcome levels before the measurement of worthwhile ratings. The feeling that life is filled with worthwhile activities may promote healthy aging and help sustain meaningful social relationships and optimal use of time at older ages.
Role of the extra Fe in K

2−
x

Fe

4+
y

Se
5
superconductors
Authors: Wang Chih-Han , Lee Chih-Chien , Huang Gwo-Tzong , Yang Jie-Yu , Wang Ming-Jye , Sheu Hwo-Shuenn , Lee Jey-Jau , Wu Maw-Kuen
Published: January 2019

Significance

This paper presents the results of a detailed structural study using synchrotron X-ray diffraction at various temperatures up to 850 °C on K

2
x

Fe

4+
y

Se
5
superconductors. The results confirm that extra Fe atoms begin to fill the empty 4d site and stabilize the structural-phase I4/m symmetry so that the lattice size remains the same even above the order–disorder temperature. The results demonstrate that the addition of extra Fe suppresses the Fe vacancy long-range order and the accompanied magnetic order so that superconductivity emerges. The significance of this research is that it provides unambiguously the structural origin for superconductivity in the K
2−x
Fe

4+
y

Se
5
superconducting system.
Inhibition of chemotherapy resistant breast cancer stem cells by a ROR1 specific antibody
Authors: Zhang Suping , Zhang Han , Ghia Emanuela M. , Huang Jiajia , Wu Liufeng , Zhang Jianchao , Lam Sharon , Lei Yang , He Jinsong , Cui Bing , Widhopf George F. , Yu Jian , Schwab Richard , Messer Karen , Jiang Wenqi , Parker Barbara A. , Carson Dennis A. , Kipps Thomas J.
Published: January 2019

Breast cancers enduring treatment with chemotherapy may be enriched for cancer stem cells or tumor-initiating cells, which have an enhanced capacity for self-renewal, tumor initiation, and/or metastasis. Breast cancer cells that express the type I tyrosine kinaselike orphan receptor ROR1 also may have such features. Here we find that the expression of ROR1 increased in breast cancer cells following treatment with chemotherapy, which also enhanced expression of genes induced by the activation of Rho-GTPases, Hippo-YAP/TAZ, or B lymphoma Mo-MLV insertion region 1 homolog (BMI1). Expression of ROR1 also enhanced the capacity of breast cancer cells to invade Matrigel, form spheroids, engraft in Rag2
−/−

γ
c

−
/
−

mice, or survive treatment with paclitaxel. Treatment of mice bearing breast cancer patient-derived xenografts (PDXs) with the humanized anti-ROR1 monoclonal antibody cirmtuzumab repressed expression of genes associated with breast cancer stemness, reduced activation of Rho-GTPases, Hippo-YAP/TAZ, or BMI1, and impaired the capacity of breast cancer PDXs to metastasize or reengraft Rag2
−/−

γ
c

−
/
−

mice. Finally, treatment of PDX-bearing mice with cirmtuzumab and paclitaxel was more effective than treatment with either alone in eradicating breast cancer PDXs. These results indicate that targeting ROR1 may improve the response to chemotherapy of patients with breast cancer.
What does constituent priming mean in the investigation of compound processing?
Authors: Libben Gary , Goral Mira , Baayen R. Harald
Published: January 2019

Most dictionary definitions for the term compound word characterize it as a word that itself
contains two or more words. Thus, a compound word such as goldfish is composed of the constituent words
gold and fish. In this report, we present evidence that compound words such as
goldfish might not contain the words gold and fish, but rather positionally
bound compound constituents (e.g., gold- and -fish) that are distinct and often in competition
with their whole word counterparts. This conceptualization has significant methodological consequences: it calls into question the
assumption that, in a traditional visual constituent priming paradigm, the participant can be said to be presented with
constituents as primes. We claim that they are not presented with constituents. Rather, they are presented with competing
free-standing words. We present evidence for the processing of Hebrew compound words that supports this perspective by revealing
that, counter-intuitively, prime constituent frequency has an attenuating effect on constituent priming. We relate our findings to
previous findings in the study of German compound processing to show that the effect that we report is fundamentally morphological
rather than positional or visual in nature. In contrast to German in which compounds are always head-final morphologically, Hebrew
compounds are always head initial. In addition, whereas German compounds are written as single words, Hebrew compounds are always
written with spaces between constituents. Thus, the commonality of patterning across German and Hebrew is independent of visual
form and constituent ordering, revealing, as we claim, core features of the constituent priming paradigm and compound
processing.
Multimodal acquisition of interactive aptitudes
Authors: Geenen Jarret
Published: January 2019

In this article, I detail incremental microgenetic alterations in the development of one particular socio-interactive aptitude: making a relevant interactive contribution. Taking heed ofClark’s (2014)call for the need to reorient our attention to investigate the pragmatics of interaction by accounting for the multiple communicative modes through which this is acccomplished I detail the ways in which parental facilitation and a flexible participatory configuration, made possible by video-conferencing technology, create conditions enabling the agentive re-introduction of a psycho-socially relevant topic. Paramount are the ways in which residual interactive specificities in introduction, co-production and multimodal configurations re-manifest suggesting a more symbiotic relationship between traditional notions of ‘message’ and ‘production’. During the microgenesis of interactive aptitudes, children are not just learningwhatconstitutes psycho-socially relevant topoi, they also acquire an understanding of exactlyhowto make the contribution through multimodal ensembles.
Debating or displaying political positions?
Authors: Gruber Helmut
Published: January 2019

This paper investigates the reference statements and rhetorical functions of politicians’ reactive (“uptaking”) statements in
parliamentary debates as well as their self-positioning effects. Uptaking moves may be used by speakers for pursuing strategic,
global discourse aims. The specific properties of such ‘uptaking’ utterances and their sequential embedding in the unfolding
discourse provide analysts with cues of speakers’ global interactional goals. Results indeed show how global and local pragmatic
factors impact content, form, and rhetorical function of MPs’ uptaking statements. The data comprises four Austrian parliamentary
sessions, which follow the inaugural speech each newly appointed Austrian chancellor has to deliver in the Austrian national
assembly at the beginning of a legislative term. Overall, four fifths of the uptaking discourse units (consisting
of ‘reference to previous statement plus comment’) refer to the government program, the inaugural speech or a previous MPs’
statement. Whereas a closer investigation of the reference statements seems to indicate a left wing vs.
right wing rhetorical pattern (with left wing and center parties referring to ‘official’ sources, while right wing parties set
their own topical agenda), investigating the rhetorical functions of the uptaking discourse units reveals a clear
government vs. opposition (but no party-specific) rhetoric: Government party MPs praise the government program (or the inaugural
speech), opposition party speakers criticize it. Both groups thus focus on the interpersonal plain of interaction. In contrast,
argumentative (or counter-argumentative) uptaking discourse units which would indicate speakers’ willingness to enter into a
rational discourse (in a Habermasian sense) with their political opponents are extremely rare. Through their rhetorical
activities, the vast majority of government and opposition speakers thus reinforce and perpetuate already known political
stances and affiliations in front of a third party (i.e. the general public watching the debates via TV or Internet livestream)
rather than presenting themselves as rational, problem-focused politicians.
A diachronic analysis of metaphor clusters in political discourse
Authors: Sun Yi , Chen Xi
Published: January 2019

The complex and abstract character of political discourse makes it difficult to be understood directly by ordinary people. Assuming
that use of metaphor could make political language easier to comprehend, more and more scholars began to focus on the study of
metaphor in political discourse. However, most of these studies paid only attention to the contrastive study of single metaphor
phenomena, while diachronic studies of metaphors still remained few.

The present paper attempts to make a diachronic analysis of metaphor clusters in American and Chinese political discourse. The data
employed are American and Chinese leaders’ political speeches, addressed to university students; the Chinese corpus contains
119021 characters, while the American corpus includes 118805 words. The research was implemented over three periods, namely before
1900, from 1900 to 2010, and from 2010 up to now (when the new term “metaphor cluster” was introduced to study the clustering
phenomena of metaphor in different periods). In addition, both qualitative analysis and qualitative analysis were employed; the
linguistic analysis tool Wmatrix and MIPVU procedures were adopted to identify metaphor clusters, thereby remedying the
shortcomings of traditional methods which identify metaphor through researchers’ intuition and perception. Qualitative analysis
was used to conduct a contrastive analysis of dominant metaphor clusters and how they tend to be used by the lecturers, both in
the American and the Chinese corpuses.

The data analysis shows that metaphor clusters abound in American and Chinese leaders’ political speeches in universities.
Generally speaking, Chinese leaders adopt more metaphor clusters than do their American counterparts. Similar metaphor clusters in
both data are: journey, family, and building. Circle and art metaphor clusters are unique to the Chinese data, while religion and
drama metaphor clusters only occur in the American data. Before 1990, leaders adopted few metaphor clusters both in America and in
China; the two decades from 1990 to 2010 witnessed a peak season of employing metaphor clusters in both Chinese and American
leaders’ speeches, whereas after 2010, the usage of metaphor clusters in Chinese data ushered in a new stage of development, with
a multitude of new metaphorical expressions having cultural connotations. The results reveal that the differences in the usage of
metaphor clusters are mainly due to the various ideologies and cultural backgrounds of the two countries. In addition, our
analysis also shows that the employment of metaphor clusters in political discourse could lead the audiences’ direction of
thinking, reduce the audiences’ comprehensive burden, and arouse the audiences’ emotions.
Population Density and Local Food Market Channels
Authors: O'Hara Jeffrey K. , Lin Jeffrey
Published: January 2019

We estimate the effect of population density on the use of local food market channels in the United States. Farms with greater market size increase direct sales to consumers, but the spatial scale of this effect operates at shorter distances than previously considered. Local farms do not use distributors to increase production for sales at shorter distances. Our results suggest that technical assistance to increase local food products sold by proximate retail outlets would be more effectively deployed assisting farms that undertake sales directly to retailers instead of marketing products through distributors.
Computational medicine: quantitative modeling of complex diseases
Authors: Tiwary Basant K
Published: January 2019

Biological complex systems are composed of numerous components that interact within and across different scales. The ever-increasing generation of high-throughput biomedical data has given us an opportunity to develop a quantitative model of nonlinear biological systems having implications in health and diseases. Multidimensional molecular data can be modeled using various statistical methods at different scales of biological organization, such as genome, transcriptome and proteome. I will discuss recent advances in the application of computational medicine in complex diseases such as network-based studies, genome-scale metabolic modeling, kinetic modeling and support vector machines with specific examples in the field of cancer, psychiatric disorders and type 2 diabetes. The recent advances in translating these computational models in diagnosis and identification of drug targets of complex diseases are discussed, as well as the challenges researchers and clinicians are facing in taking computational medicine from the bench to bedside.
The Path to Group A Streptococcus Vaccines: World Health Organization Research and Development Technology Roadmap and Preferred Product Characteristics
Authors: Vekemans Johan , Gouvea-Reis Fernando , Kim Jerome H , Excler Jean-Louis , Smeesters Pierre R , O’Brien Katherine L , Van Beneden Chris A , Steer Andrew C , Carapetis Jonathan R , Kaslow David C
Published: January 2019

Group A Streptococcus (GAS) infections result in a considerable underappreciated burden of acute and chronic disease globally. A 2018 World Health Assembly resolution calls for better control and prevention. Providing guidance on global health research needs is an important World Health Organization (WHO) activity, influencing prioritization of investments. Here, the role, status, and directions in GAS vaccines research are discussed. WHO preferred product characteristics and a research and development technology roadmap, briefly presented, offer an actionable framework for vaccine development to regulatory and policy decision making, availability, and use. GAS vaccines should be considered for global prevention of the range of clinical manifestations and associated antibiotic use. Impediments related to antigen diversity, safety concerns, and the difficulty to establish vaccine efficacy against rheumatic heart disease are discussed. Demonstration of vaccine efficacy against pharyngitis and skin infections constitutes a key near-term strategic goal. Investments and collaborative partnerships to diversify and advance vaccine candidates are needed.