bluuebunny/crossref_metadata_2025 huggingface dataset:
Extragalactic archaeology with the C, N, and O chemical abundances
Authors: Vincenzo Fiorenzo , Kobayashi Chiaki
Published: February 2018

We predict how the C, N, and O abundances within the interstellar medium of galaxies evolve as functions of the galaxy star formation history (SFH). We adopt a hydrodynamical cosmological simulation, focusing on three star-forming disc galaxies with different SFHs. By assuming failed supernovae, we can predict an increasing trend of the gas-phase N/O–O/H abundance diagram, which was not produced in our previous simulations without failed supernovae. At high redshifts, contrary to the predictions of classical chemical evolution models with instantaneous mixing approximation, we find almost flat trends in the N/O–O/H diagram, which are due to the contribution of intermediate-mass stars together with an inhomogeneous chemical enrichment. Finally, we also predict that the average N/O and C/O steadily increase as functions of time, while the average C/N decreases, due to the mass and metallicity dependence of the yields of asymptotic giant branch stars; such variations are more marked during more intense star formation episodes. Our predictions on the CNO abundance evolution can be used to study the SFH of disc galaxies with the James Webb Space Telescope.
High-resolution observations of IRAS 08544−4431
Authors: Bujarrabal V. , Castro-Carrizo A. , Van Winckel H. , Alcolea J. , Sánchez Contreras C. , Santander-García M. , Hillen M.
Published: February 2018

Context. Aims. In order to study the effects of rotating disks in the post-asymptotic giant branch (post-AGB) evolution, we observe a class of binary post-AGB stars that seem to be systematically surrounded by equatorial disks and slow outflows. Although the rotating dynamics had only been well identified in three cases, the study of such structures is thought to be fundamental to the understanding of the formation of disks in various phases of the late evolution of binary stars and the ejection of planetary nebulae from evolved stars.

Methods. We present ALMA maps of 12CO and 13CO J = 3−2 lines in the source IRAS 08544−4431, which belongs to the above mentioned class of objects. We analyzed the data by means of nebula models, which account for the expectedly composite source and can reproduce the data. From our modeling, we estimated the main nebula parameters, including the structure and dynamics and the density and temperature distributions. We discuss the uncertainties of the derived values and, in particular, their dependence on the distance.

Results. Our observations reveal the presence of an equatorial disk in rotation; a low-velocity outflow is also found, probably formed of gas expelled from the disk. The main characteristics of our observations and modeling of IRAS 08544−4431 are similar to those of better studied objects, confirming our interpretation. The disk rotation indicates a total central mass of about 1.8 M⊙, for a distance of 1100 pc. The disk is found to be relatively extended and has a typical diameter of ~4 × 1016 cm. The total nebular mass is ~2 × 10−2 M⊙, of which ~90% corresponds to the disk. Assuming that the outflow is due to mass loss from the disk, we derive a disk lifetime of ~10 000 yr. The disk angular momentum is found to be comparable to that of the binary system at present. Assuming that the disk angular momentum was transferred from the binary system, as expected, the high values of the disk angular momentum in this and other similar disks suggest that the size of the stellar orbits has significantly decreased as a consequence of disk formation.
Sub-arcsecond imaging of Arp 299-A at 150 MHz with LOFAR: Evidence for a starburst-driven outflow
Authors: Ramírez-Olivencia N. , Varenius E. , Pérez-Torres M. , Alberdi A. , Pérez E. , Alonso-Herrero A. , Deller A. , Herrero-Illana R. , Moldón J. , Barcos-Muñoz L. , Martí-Vidal I.
Published: February 2018

We report on the first sub-arcsecond (0.44 × 0.41 arcsec2) angular resolution image at 150 MHz of the A-nucleus in the luminous infrared galaxy Arp 299, from International Low Frequency Array (LOFAR) Telescope observations. The most remarkable finding is that of an intriguing two-sided, filamentary structure emanating from the A-nucleus, which we interpret as an outflow that extends up to at least 14 arcsec from the A-nucleus in the N–S direction ( ≈5 kpc deprojected size) and accounts for almost 40% of the extended emission of the entire galaxy system. We also discuss HST/NICMOS [FeII] 1.64 μm and H2 2.12 μm images of Arp 299-A, which show similar features to those unveiled by our 150 MHz LOFAR observations, providing strong morphological support for the outflow scenario. Finally, we discuss unpublished Na I D spectra that confirm the outflow nature of this structure. From energetic arguments, we rule out the low-luminosity active galactic nucleus in Arp 299-A as a driver for the outflow. On the contrary, the powerful, compact starburst in the central regions of Arp 299-A provides plenty of mechanical energy to sustain an outflow, and we conclude that the intense supernova (SN) activity in the nuclear region of Arp 299-A is driving the observed outflow. We estimate that the starburst wind can support a mass-outflow rate in the range (11–63 M⊙ yr−1) at speeds of up to 370–890 km s−1, and is relatively young, with an estimated kinematic age of 3–7 Myr. Those results open an avenue to the use of low-frequency (150 MHz), sub-arcsecond imaging with LOFAR to detect outflows in the central regions of local luminous infrared galaxies.
Synthesis of Cyclic 3-Aryl-Substituted 1,2-Dicarbonyl Compounds via Suzuki Cross-Coupling Reactions
Authors: Lopp Margus , Lopušanskaja Eleana , Paju Anne , Järving Ivar
Published: February 2018

A method for the synthesis of cyclic 3-aryl- and heteroaryl-substituted 1,2-dicarbonyl compounds with different ring sizes by using a Suzuki cross-coupling reaction between 3-halo-1,2-dicarbonyl compounds and arylboronic acids is developed. The 3-halo-1,2-dicarbonyl substrates are easily available from 1,2-dicarbonyl compounds. The method is versatile, affording good to high yields of the target compounds.
Product Divergence in Coinage-Metal-Catalyzed Reactions of π-Rich Compounds
Authors: Chan Philip , Boyle Joshua , Zhao Yichao
Published: February 2018

This short review aims to summarize how the product outcome of reactions of a common starting material can sometimes be controlled by the judicious choice of copper, silver or gold as the catalyst. It highlights the different reactivities observed in the functional group transformations of π-rich substrates mediated by the three group 11 metal salts.

1 Introduction

2 Reactions of Propargyl Amines, Esters and Their Derivatives

3 Reactions of Phenylacetylene Derivatives

4 Reactions of π-Rich Alcohols and Ethers

5 Indolyl Cyclopropene and Alkynone Rearrangements

6 Reactions Involving Metal-Carbene and Metal-Carbenoid Intermediates

7 Conclusion
Reconstruction of Tragus and External Auditory Meatus using Remnant Auricle during Microtia Reconstruction
Authors: Hu Yi-gao , Ding Wei , Tan Jun , Chen Xin , Luo Tao , Zhang Bo , Liu Xiao-jia , Li Gao-feng
Published: February 2018

This article investigates an effective method with which to reconstruct the tragus and external auditory meatus for microtia reconstruction. The external ear was reconstructed using a delayed postauricular skin flap in patients with congenital microtia. After the first stage of delaying the postauricular skin flap and the second stage of otoplasty with ear framework fabricated from autogenous rib cartilage draping with the delayed skin flap, the third stage involved tragus and external auditory meatus canaloplasty. After designing the remnant auricle flap, the lower part was trimmed and the tragus was reconstructed. The upper part was trimmed into a thin skin flap, which was rotated and used to cover the hollowed wound posterosuperior to the tragus so as to mimic the external auditory meatus. If remnant wounds were present, skin grafting was conducted. In total, 121 patients with congenital microtia were treated from March 2010 to March 2016. The reconstructed tragus and external auditory meatus were well formed, and all wounds healed well. No severe complications such as flap necrosis occurred. Six months postoperatively, the morphology of the reconstructed tragus and external auditory meatus was good. Overall, the patients and their families were satisfied. The use of remnant auricle to reconstruct the tragus and external auditory meatus is an effective auricular reconstruction technique.
Quality of Life and Functional Outcomes after Multiligament Knee Reconstruction
Authors: Hatch George , Villacis Diego , Damodar Dhanur , Dacey Michael , Yi Anthony
Published: February 2018

We aimed to determine factors that affect the quality of life of patients undergoing a standardized surgical and postoperative management protocol for knee dislocations. A total of 31 patients (33 knees) were included in this study. We contacted patients at a minimum of 12 months postoperatively (mean: 38 months; range, 12–111 months) and administered the previously validated Multiligament Quality of Life questionnaire (ML-QOL), 2000 International Knee Documentation Committee Subjective Knee Form (IKDC), and Lysholm Knee Scoring Scale. We performed independent two-sample t-tests and age-adjusted multivariable linear regression analysis to examine the difference in these scores. Patients who underwent previous knee ligament surgery had significantly worse mean ML-QOL scores relative to patients who did not undergo previous knee ligament surgery (114.3 versus 80.4; p = 0.004) (higher score indicates worse quality of life). All other differences in the ML-QOL scores were not statistically significant. IKDC and Lysholm scores did not differ significantly with regards to the studied variables. Among patients with no previous knee ligament surgery, patients undergoing surgery within 3 weeks of injury had significantly worse mean ML-QOL scores relative to patients undergoing surgery greater than 3 weeks after their injury (98.7 versus 74.7; p = 0.042) and patients with Schenck classification of III or IV had significantly worse mean ML-QOL scores relative to patient with a Schenck classification of I or II (88.7 versus 62.9; p = 0.015). We found that patients with a previous history of knee ligament surgery had a significantly worse quality of life relative to those with no history of knee ligament surgery. This is a level III, retrospective cohort study.
Optimum operation of multi-energy carriers in the context of an energy hub considering a wind generator based on linear programming
Authors: Ezzati Seyed Meisam , Faghihi Framarz , Shourkaei Hosein Mohammadnezhad , Mozafari Seyed Babak , Soleymani Soodabeh
Published: February 2018

This paper presents a model that can be easily used to resolve the energy hub operation problem. The proposed model considers the uncertainty in the input and output ports. The energy hub optimum operation problem needs to be resolved in order to supply several energy loads in combination at the minimum total energy cost. In this study, mixed-integer linear programming was applied to formulate this optimization problem. The power balance, energy storage, and converter limitations of the input and output ports were included as equality and inequality constraints. The total cost of an energy hub was determined by the price of energy carriers. Eventually, deterministic and stochastic versions of the proposed model were tested in a case study. In the test system, electricity, gas, and wind generation were used in the input port, and the output port contained the electrical and thermal load. The results demonstrated that a stochastic model based on different scenarios was more realistic than a deterministic model. However, the total operating cost of an energy hub decreased more in the stochastic model compared to the deterministic model.
Vibrational treatment of the formic acid double minimum case in valence coordinates
Authors: Richter Falk , Carbonnière P.
Published: February 2018

One single full dimensional valence coordinate HCOOH ground state potential energy surface accurate for both cis and trans conformers for all levels up to 6000 cm−1 relative to trans zero point energy has been generated at CCSD(T)-F12a/aug-cc-pVTZ level. The fundamentals and a set of eigenfunctions complete up to about 3120 and 2660 cm−1 for trans- and cis-HCOOH, respectively, have been calculated and assigned using the improved relaxation method of the Heidelberg multi-configuration time-dependent Hartree package and an exact expression for the kinetic energy in valence coordinates generated by the TANA program. The calculated trans fundamental transition frequencies agree with experiment to within 5 cm−1. A few reassignments are suggested. Our results discard any cis trans delocalization effects for vibrational eigenfunctions up to 3640 cm−1 relative to trans zero point energy.
Dynamic impedance compensation for wireless power transfer using conjugate power
Authors: Liu Suqi , Tan Jianping , Wen Xue
Published: February 2018

Wireless power transfer (WPT) via coupled magnetic resonances has been in development for over a decade. However, the frequency splitting phenomenon occurs in the over-coupled region. Thus, the output power of the two-coil system achieves the maximum output power at the two splitting angular frequencies, and not at the natural resonant angular frequency. According to the maximum power transfer theorem, the impedance compensation method was adopted in many WPT projects. However, it remains a challenge to achieve the maximum output power and transmission efficiency in a fixed-frequency mode. In this study, dynamic impedance compensation for WPT was presented by utilizing the compensator within a virtual three-coil WPT system. First, the circuit model was established and transfer characteristics of a system were studied by utilizing circuit theories. Second, the power superposition of the WPT system was carefully researched. When a pair of compensating coils was inserted into the transmitter loop, the conjugate power of the compensator loop was created via magnetic coupling of the two compensating coils that insert into the transmitter loop. The mechanism for dynamic impedance compensation for wireless power transfer was then provided by investigating a virtual three-coil WPT system. Finally, the experimental circuit of a virtual three-coil WPT system was designed, and experimental results are consistent with the theoretical analysis, which achieves the maximum output power and transmission efficiency.
Strain relaxation of germanium-tin (GeSn) fins
Authors: Kang Yuye , Huang Yi-Chiau , Lee Kwang Hong , Bao Shuyu , Wang Wei , Lei Dian , Masudy-Panah Saeid , Dong Yuan , Wu Ying , Xu Shengqiang , Tan Chuan Seng , Gong Xiao , Yeo Yee-Chia
Published: February 2018

Strain relaxation of biaxially strained Ge1-xSnx layer when it is patterned into Ge1-xSnx fin structures is studied. Ge1-xSnx-on-insulator (GeSnOI) substrate was realized using a direct wafer bonding (DWB) technique and Ge1-xSnx fin structures were formed by electron beam lithography (EBL) patterning and dry etching. The strain in the Ge1-xSnx fins having fin widths (WFin) ranging from 1 μm down to 80 nm was characterized using micro-Raman spectroscopy. Raman measurements show that the strain relaxation increases with decreasing WFin. Finite element (FE) simulation shows that the strain component in the transverse direction relaxes with decreasing WFin, while the strain component along the fin direction remains unchanged. For various Ge1-xSnx fin widths, transverse strain relaxation was further extracted using micro-Raman spectroscopy, which is consistent with the simulation results.
An analytic investigation for the edge effect on mechanical properties of graphene nanoribbons
Authors: Han Guang-Rong , Sun Jia-Sheng , Jiang Jin-Wu
Published: February 2018

We derive analytical expressions for the Young's modulus and the Poisson's ratio of the graphene nanoribbon, in which free edges are warped by the compressive edge stress. Our analytical formulas explicitly illustrate the reduction of the Young's modulus by the warped free edges, leading to the obvious width dependence for the Young's modulus of the graphene nanoribbon. The Poisson's ratio is also reduced by the warped free edges, and negative Poisson's ratio can be achieved in the graphene nanoribbon with an ultra-narrow width. These results are comparable with previous theoretical works.
Significant enhancement of light absorption in undoped graphene using dielectric multilayer system
Authors: Nulli Sylvain A. , Ukhtary M. Shoufie , Saito Riichiro
Published: February 2018

The interband optical conductivity of undoped graphene gives only 2.3% absorption of light regardless of the light frequency. In this work, we show that by enhancing the electric field on a graphene surface through the interference effect, the light absorption of an undoped monolayer graphene can be much enhanced up to 50%. The monolayer graphene is put at the center of a specially designed multilayer structure of dielectric media. The enhanced absorption can be achieved for any arbitrary frequency by changing the number of layers or the refractive index of the layers. We also show that the absorption of light is used by Joule's heating of graphene which can be applied for local heating by light.
The investigation on hydrogenation platform for silicon solar cells based on high intensity infrared LEDs
Authors: Shao Jianbo , Xi Xi , Li Chao , Liu Guilin , Li Guohua , Zhu Yiqing , Wang Xiao , Qian Weiying , Chen Guoqing , Chen Rulong , Zhu Tuo
Published: February 2018

The research on the hydrogen passivation process for silicon solar cells has been developed for a long time. Recently, researchers have investigated the use of lasers as light sources. It has been found that hydrogen passivation technology can improve the minority carrier lifetime and passivate some impurities and defects in silicon solar cells. In this paper, a hydrogenation platform for silicon solar cells based on high intensity infrared LEDs of 940 nm was built. After a number of comparative experiments, electrical characteristics, photo-luminescence images, and light beam induced current were applied before and after hydrogenation to distinguish the passivation effect. It was found that the effect of hydrogen passivation on monocrystalline boron-doped passivated emitter and rear contact (PERC) solar cells by using infrared LEDs as the light source was satisfactory under the condition of suitable light intensity and temperature. It has a remarkable effect on improving the electrical characteristics and increasing the efficiency of monocrystalline boron-doped PERC solar cells based on high intensity infrared LEDs of 940 nm.
Asymptotic convertibility of entanglement: An information-spectrum approach to entanglement concentration and dilution
Authors: Jiao Yong , Wakakuwa Eyuri , Ogawa Tomohiro
Published: February 2018

We consider asymptotic convertibility of an arbitrary sequence of bipartite pure states into another by local operations and classical communication (LOCC). We adopt an information-spectrum approach to address cases where each element of the sequences is not necessarily a tensor power of a bipartite pure state. We derive necessary and sufficient conditions for the LOCC convertibility of one sequence to another in terms of spectral entropy rates of entanglement of the sequences. Based on these results, we also provide simple proofs for previously known results on the optimal rates of entanglement concentration and dilution of general sequences of bipartite pure states.
Modulating the line shape of magnetoconductance by varying the charge injection in polymer light-emitting diodes
Authors: Chitraningrum Nidya , Chu Ting-Yi , Huang Ping-Tsung , Wen Ten-Chin , Guo Tzung-Fang
Published: February 2018

We fabricate the phenyl-substituted poly(p-phenylene vinylene) copolymer (super yellow, SY-PPV)-based polymer light-emitting diodes (PLEDs) with different device architectures to modulate the injection of opposite charge carriers and investigate the corresponding magnetoconductance (MC) responses. At the first glance, we find that all PLEDs exhibit the positive MC responses. By applying the mathematical analysis to fit the curves with two empirical equations of a non-Lorentzian and a Lorentzian function, we are able to extract the hidden negative MC component from the positive MC curve. We attribute the growth of the negative MC component to the reduced interaction of the triplet excitons with charges to generate the free charge carriers as modulated by the applied magnetic field, known as the triplet exciton-charge reaction, by analyzing MC responses for PLEDs of the charge-unbalanced and hole-blocking device configurations. The negative MC component causes the broadening of the line shape in MC curves.
Non-linear Alfvén waves in spin-1/2 quantum plasma
Authors: Jan Qasim , Mushtaq A. , Ikram M.
Published: February 2018

Nonlinear circularly polarized Alfvén waves are studied in Fermionic spin-1/2 quantum plasmas. Using the basic equations for Hall magnetohydrodynamics including quantum corrections, the set of Zakharov-like equations are obtained for circularly polarized nonlinear Alfvén waves. In order to investigate the properties of the Alfvén solitary structure in the presence of spin magnetization and quantum plasma beta, the Sagdeev potential approach is employed. For the case of right-handed circularly polarized Alfvén waves, the amplitude of the Sagdeev potential and the associated solitary profile is observed to enhance with the increase of quantum plasma beta and magnetization energy due to electron spin-1/2 effects. However, it is found that the amplitude of the Sagdeev potential and the related solitary profile decrease with the increasing values of quantum plasma beta and magnetization energy for the case of left-handed circularly polarized Alfvén waves. An increase in the width of the solitary structure is also observed with the increase in the value of magnetization energy for the case of the left-handed circularly polarized wave. An investigation of the modulational instability is also inspected with the effects of spin magnetization and quantum plasma beta.
Application of nonlinear rheology to assess the effect of secondary nanofiller on network structure of hybrid polymer nanocomposites
Authors: Kamkar Milad , Aliabadian Ehsan , Shayesteh Zeraati Ali , Sundararaj Uttandaraman
Published: February 2018

Carbon nanotube (CNT)/polymer nanocomposites exhibit excellent electrical properties by forming a percolated network. Adding a secondary filler can significantly affect the CNTs’ network, resulting in changing the electrical properties. In this work, we investigated the effect of adding manganese dioxide nanowires (MnO2NWs) as a secondary nanofiller on the CNTs’ network structure inside a poly(vinylidene fluoride) (PVDF) matrix. Incorporating MnO2NWs to PVDF/CNT samples produced a better state of dispersion of CNTs, as corroborated by light microscopy and transmission electron microscopy. The steady shear and oscillatory shear flows were employed to obtain a better insight into the nanofiller structure and viscoelastic behavior of the nanocomposites. The transient response under steady shear flow revealed that the stress overshoot of hybrid nanocomposites (two-fillers), PVDF/CNT/MnO2NWs, increased dramatically in comparison to binary nanocomposites (single-filler), PVDF/CNT and PVDF/MnO2NWs. This can be attributed to microstructural changes. Large amplitude oscillatory shear characterization was also performed to further investigate the effect of the secondary nanofiller on the nonlinear viscoelastic behavior of the samples. The nonlinear rheological observations were explained using quantitative nonlinear parameters [strain-stiffening ratio (S) and shear-thickening ratio (T)] and Lissajous-Bowditch plots. Results indicated that a more rigid nanofiller network was formed for the hybrid nanocomposites due to the better dispersion state of CNTs and this led to a more nonlinear viscoelastic behavior.
Phosphorous doped p-type MoS2 polycrystalline thin films via direct sulfurization of Mo film
Authors: Momose Tomohiro , Nakamura Atsushi , Daniel Moraru , Shimomura Masaru
Published: February 2018

We report on the successful synthesis of a p-type, substitutional doping at S-site, MoS2 thin film using Phosphorous (P) as the dopant. MoS2 thin films were directly sulfurized for molybdenum films by chemical vapor deposition technique. Undoped MoS2 film showed n-type behavior and P doped samples showed p-type behavior by Hall-effect measurements in a van der Pauw (vdP) configuration of 10×10 mm2 area samples and showed ohmic behavior between the silver paste contacts. The donor and the acceptor concentration were detected to be ∼2.6×1015 cm-3 and ∼1.0×1019 cm-3, respectively. Hall-effect mobility was 61.7 cm2V-1s-1 for undoped and varied in the range of 15.5 ∼ 0.5 cm2V-1s-1 with P supply rate. However, the performance of field-effect transistors (FETs) declined by double Schottky barrier contacts where the region between Ni electrodes on the source/drain contact and the MoS2 back-gate cannot be depleted and behaves as a 3D material when used in transistor geometry, resulting in poor on/off ratio. Nevertheless, the FETs exhibit hole transport and the field-effect mobility showed values as high as the Hall-effect mobility, 76 cm2V-1s-1 in undoped MoS2 with p-type behavior and 43 cm2V-1s-1 for MoS2:P. Our findings provide important insights into the doping constraints for transition metal dichalcogenides.
Infrared spectroscopy of the ν3 band of C3 in helium droplets
Authors: Harruff-Miller Barbara A. , Bunker Christopher E. , Lewis William K.
Published: February 2018

The C3 molecule is an important species known to participate in key chemical reactions in combustion and astrochemistry. Its occurrence in environments of interest, its intramolecular physics, and its intermolecular reactivity have been areas of extensive and ongoing study. Much of the interest in C3 is related to investigating its interactions with other species relevant to combustion processes or astrochemistry. Helium droplet methods offer a promising route to assemble and study a wide variety of novel complexes, clusters, and adducts made from C3. Here we report the results of our recent efforts to dope cold helium droplets with C3 molecules and record the rotationally-resolved infrared spectrum of the embedded C3. The spectrum consists of P(2), R(0), and R(2) lines well-described by a linear rotor Hamiltonian with ν0 = 2039.09(2) cm-1, B = 0.204(5) cm-1, and T = 0.37 K. The B rotational constant of the C3 molecule is found to be reduced from its gas-phase value by a factor of 2.1 due to rotational following by the helium solvent.
Post deposition annealing effect on the properties of Al2O3/InP interface
Authors: Kim Hogyoung , Kim Dong Ha , Choi Byung Joon
Published: February 2018

Post deposition in-situ annealing effect on the interfacial and electrical properties of Au/Al2O3/n-InP junctions were investigated. With increasing the annealing time, both the barrier height and ideality factor changed slightly but the series resistance decreased significantly. Photoluminescence (PL) measurements showed that the intensities of both the near band edge (NBE) emission from InP and defect-related bands (DBs) from Al2O3 decreased with 30 min annealing. With increasing the annealing time, the diffusion of oxygen (indium) atoms into Al2O3/InP interface (into Al2O3 layer) occurred more significantly, giving rise to the increase of the interface state density. Therefore, the out-diffusion of oxygen atoms from Al2O3 during the annealing process should be controlled carefully to optimize the Al2O3/InP based devices.
Tuning spontaneous polarization to alter water oxidation/reduction activities of LiNbO3
Authors: Fu Hongwei , Song Yan , Wu Yangqing , Huang Huiting , Fan Guozheng , Xu Jun , Li Zhaosheng , Zou Zhigang
Published: February 2018

Here, we investigated the effects of spontaneous polarization on photoreactivities by using a ferroelectric material n-type congruent LiNbO3 single crystal as a model. It was found that c+ LiNbO3 was superior to c− LiNbO3 in photocatalytic water reduction, while c− LiNbO3 exhibited better performances for photoelectrochemical water oxidation than c+ LiNbO3. Using Kelvin probe force microscopy and open circuit potential methods, we observed that c− LiNbO3 generated a higher photovoltage and had a slower charge-recombination rate than c+ LiNbO3. The results of electrochemical impedance spectroscopy measurements indicated that c− LiNbO3 may favor the hole transport from the bulk to the surface compared with c+ LiNbO3, leading to the anisotropic performances of c+ and c− LiNbO3 in water oxidation/reduction. Therefore, tuning the direction of the polarization may be a strategy to dramatically prompt the photoreactivities of water oxidation or reduction.
Genetic resistance to purine nucleoside phosphorylase inhibition in
Plasmodium falciparum
Authors: Ducati Rodrigo G. , Namanja-Magliano Hilda A. , Harijan Rajesh K. , Fajardo J. Eduardo , Fiser Andras , Daily Johanna P. , Schramm Vern L.
Published: February 2018

Plasmodium falciparum
causes the most lethal form of human malaria and is a global health concern. The parasite responds to antimalarial therapies by developing drug resistance. The continuous development of new antimalarials with novel mechanisms of action is a priority for drug combination therapies. The use of transition-state analog inhibitors to block essential steps in purine salvage has been proposed as a new antimalarial approach. Mutations that reduce transition-state analog binding are also expected to reduce the essential catalytic function of the target. We have previously reported that inhibition of host and
P. falciparum
purine nucleoside phosphorylase (
Pf
PNP) by DADMe-Immucillin-G (DADMe-ImmG) causes purine starvation and parasite death in vitro and in primate infection models.
P. falciparum
cultured under incremental DADMe-ImmG drug pressure initially exhibited increased
Pf
PNP gene copy number and protein expression. At increased drug pressure, additional
Pf
PNP gene copies appeared with point mutations at catalytic site residues involved in drug binding. Mutant
Pf
PNPs from resistant clones demonstrated reduced affinity for DADMe-ImmG, but also reduced catalytic efficiency. The catalytic defects were partially overcome by gene amplification in the region expressing
Pf
PNP. Crystal structures of native and mutated
Pf
PNPs demonstrate altered catalytic site contacts to DADMe-ImmG. Both point mutations and gene amplification are required to overcome purine starvation induced by DADMe-ImmG. Resistance developed slowly, over 136 generations (2
136
clonal selection). Transition-state analog inhibitors against
Pf
PNP are slow to induce resistance and may have promise in malaria therapy.
Experimental evidence of low-density liquid water upon rapid decompression
Authors: Lin Chuanlong , Smith Jesse S. , Sinogeikin Stanislav V. , Shen Guoyin
Published: February 2018

Significance

To understand water’s anomalous behavior, a two-liquid model with a high-density liquid and a low-density liquid (LDL) has been proposed from theoretical simulations, and is gradually gaining ground. However, it has been experimentally challenging to probe the region of the phase diagram of H
2
O where the LDL phase is expected to occur. We overcome the experimental challenge by using a technique of rapid decompression integrated with fast synchrotron measurements, and show that the region of LDL is accessible via decompression of a high-pressure crystal. We report the experimental evidence of the LDL from in situ X-ray diffraction and its crystallization process, providing a kinetic pathway for the appearance of LDL as an intermediate phase in the crystal–crystal transformation upon decompression.
Companies’ contribution to sustainability through global supply chains
Authors: Thorlakson Tannis , de Zegher Joann F. , Lambin Eric F.
Published: February 2018

Global supply chains play a critical role in many of the most pressing environmental stresses and social struggles identified by the United Nations’ Sustainable Development Goals (SDGs). Responding to calls from the global community, companies are adopting a variety of voluntary practices to improve the environmental and/or social management of their suppliers’ activities. We develop a global survey of 449 publicly listed companies in the food, textile, and wood-products sectors with annual reports in English to provide insight into how the private sector contributes to advancing the SDGs via such sustainable-sourcing practices. We find that while 52% of companies use at least one sustainable-sourcing practice, these practices are limited in scope; 71% relates to only one or a few input materials and 60.5% apply to only first-tier suppliers. We also find that sustainable-sourcing practices typically address a small subset of the sustainability challenges laid out by the SDGs, primarily focusing on labor rights and compliance with national laws. Consistent with existing hypotheses, companies that face consumer and civil society pressure are associated with a significantly higher probability of adopting sustainable-sourcing practices. Our findings highlight the opportunities and limitations of corporate sustainable-sourcing practices in addressing the myriad sustainability challenges facing our world today.
Normal aging induces A1-like astrocyte reactivity
Authors: Clarke Laura E. , Liddelow Shane A. , Chakraborty Chandrani , Münch Alexandra E. , Heiman Myriam , Barres Ben A.
Published: February 2018

The decline of cognitive function occurs with aging, but the mechanisms responsible are unknown. Astrocytes instruct the formation, maturation, and elimination of synapses, and impairment of these functions has been implicated in many diseases. These findings raise the question of whether astrocyte dysfunction could contribute to cognitive decline in aging. We used the Bac-Trap method to perform RNA sequencing of astrocytes from different brain regions across the lifespan of the mouse. We found that astrocytes have region-specific transcriptional identities that change with age in a region-dependent manner. We validated our findings using fluorescence in situ hybridization and quantitative PCR. Detailed analysis of the differentially expressed genes in aging revealed that aged astrocytes take on a reactive phenotype of neuroinflammatory A1-like reactive astrocytes. Hippocampal and striatal astrocytes up-regulated a greater number of reactive astrocyte genes compared with cortical astrocytes. Moreover, aged brains formed many more A1 reactive astrocytes in response to the neuroinflammation inducer lipopolysaccharide. We found that the aging-induced up-regulation of reactive astrocyte genes was significantly reduced in mice lacking the microglial-secreted cytokines (IL-1α, TNF, and C1q) known to induce A1 reactive astrocyte formation, indicating that microglia promote astrocyte activation in aging. Since A1 reactive astrocytes lose the ability to carry out their normal functions, produce complement components, and release a toxic factor which kills neurons and oligodendrocytes, the aging-induced up-regulation of reactive genes by astrocytes could contribute to the cognitive decline in vulnerable brain regions in normal aging and contribute to the greater vulnerability of the aged brain to injury.
Spatial reconfigurations of Spanish in postmodernity
Authors: Lynch Andrew
Published: February 2018

In this chapter, I propose four principal ways in which the Spanish language is being spatially reconfigured vis-à-vis English and local minoritized languages in postmodernity: (1) the ideological relocation of Spanish in the global ‘marketplace’ economy; (2) the propagation of English-influenced discursive patterns within the context of late capitalism, e.g., preference for familiar forms of pronominal address (tuteo) in commerce; (3) the incursion of English in public life and education, placing traditionally minoritized languages in sharper relief in the linguistic landscape; and (4) the normativization and normalization of Spanish in cyberspace and in global mass media, where English is hegemonic. I suggest that these ideological phenomena will condition structural and discursive variations in Spanish in the years ahead.
Hard come, easy go
Authors: Romero Rey , Sessarego Sandro
Published: February 2018

This study analyzes patterns in syntax-pragmatics (subject pronoun use) and syntax-morphology (nominal and verbal phi-agreement) interfaces in two unrelated varieties of Spanish, namely Afro-Ecuadorian Spanish (AES) and Istanbulite Judeo-Spanish (IJS). In spite of their geographical distance, the traditional variety of older AES speakers and the contemporary variety of younger IJS informants share similar patterns in the aforementioned features. We account for this parallel by proposing a model of cross-generational contact-induced language transmission that is grounded in current theoretical assumptions on the architecture of the faculty of language, its modularity and the vulnerability of modular interfaces. This model suggests that patterns in both traditional AES and contemporary IJS are actually nativized traces of advanced second-language acquisition (SLA) strategies or early first-language attrition (FLA).
Discourse markers in variation
Authors: Sinnott Sarah
Published: February 2018

This chapter explores the variation between the Spanish discourse markers por tanto and por lo tanto from a pragmatic perspective. The data, extracted from a corpus built using blog commentary, are categorized according to the type of causality expressed in the construction, as well as whether or not the speaker is involved in a verbal argument. Analysis reveals that por lo tanto is used more frequently than por tanto when epistemic causality is expressed as well as when the speaker is engaged in an argument. This leads to the conclusion that por lo tanto contributes greater argumentative strength to an utterance than does por tanto.
Yo no le conocí a mi abuela
Authors: Ramírez-Cruz Héctor
Published: February 2018

This paper treats the use of third-person pronominal objects le, lo and la in Amazonian Colombian Spanish. Pronoun selection was analyzed in relation to linguistic variables (case and grammatical gender of the co-referent), extra-linguistic variables concerning the speakers (age, gender and occupation) and a geographic variable (municipality). Results show that only linguistic variables have a significant effect on pronoun selection. In particular, we observe a significant interaction of case with grammatical gender, indicating a greater proportion of leísmo for feminine co-referents than for masculine co-referents. These findings contribute to understanding Spanish third-person pronominal objects in language contact, with additional insights about competition and second language learning strategies.
Attitudes toward morphosyntactic variation in the Spanish of Valencian speakers
Authors: Piqueres Gilabert Rosa María , Fuss Matthew
Published: February 2018

Blas Arroyo (1991, 1993, 1999, 2011) and González Martínez & Blas Arroyo (2011) identified degrees of variation in the morphosyntax of the Spanish of Valencia. Blas Arroyo (1993) observed variation in the use of locative prepositions a/en “at/in”, partitive de “of” and expletive que “that” in interrogative sentences. This paper describes how these variables are evaluated, using the matched-guise technique (Lambert et al. 1960). Four Valencian guise speakers from Castellón pronounced 12 sentences containing these three variables. A matched-guise test was completed to determine the attitudes of 31 Valencian-Spanish bilinguals toward the variation in these patterns. Results reveal a significant difference in the socioeconomic status evaluation for locative a/en, while all non-standard variants share positive evaluations for the personal attractiveness sphere. There is no gender or quality voice effect, which reinforces the validity of this instrument. Findings are discussed to understand the meaning of morphosyntactic variation in Castellón.
Stable variation or change in progress? A sociolinguistic analysis of pa(ra) in the Spanish of Venezuela
Authors: Fafulas Stephen , Díaz-Campos Manuel , Gradoville Michael
Published: February 2018

Sociolinguistic analyses of pa(ra) “for” have found that both linguistic and social factors play a significant role in speaker use of the reduced (pa’) and full (para) forms (e.g., Bentivoglio et al. 2005). However, no study to date has analyzed the extent to which production of these forms is most indicative of stable variation or a change in progress. The current study investigates 160 interviews conducted with speakers from Caracas, Venezuela and offers a comprehensive analysis of the variables of socioeconomic class, age, gender, and style in order to determine whether pa(ra) is best considered a stable variable or a change in progress in this speech community. Results indicate that the reduction of para lacks the hallmarks typical of linguistic change in progress.
Spanish in Colombia and New York City
Authors: Orozco Rafael
Published: February 2018

This volume fills a void in language variation and change research. It is the first to provide an empirical, comparative study of Spanish in Colombia and New York City. Remarkable similarities in the linguistic conditioning on language variation in both communities contrast with interesting differences in the effects of social predictors. The book provides a window into the effects of language and dialect contact on change and serves as a model for studies comparing diasporic populations to their home speech communities.
Discourse Markers and (Dis)fluency
Authors: Crible Ludivine
Published: February 2018

Spoken language is characterized by the occurrence of linguistic devices such as discourse markers (e.g. so, well, you know, I mean) and other so-called “disfluent” phenomena, which reflect the temporal nature of the cognitive mechanisms underlying speech production and comprehension. The purpose of this book is to distinguish between strategic vs. symptomatic uses of these markers on the basis of their combination, function and distribution across several registers in English and French. Through deep quantitative and qualitative analyses of manually annotated features in the new DisFrEn corpus, this usage-based study provides (i) an exhaustive portrait of discourse markers in English and French and (ii) a scale of (dis)fluency against which different configurations of discourse markers can be diagnosed as rather fluent or disfluent. By bringing together discourse markers and (dis)fluency under one coherent framework, this book is a unique contribution to corpus-based pragmatics, discourse analysis and crosslinguistic fluency research.
Constructional pressures on ‘sit’ in Modern Greek
Authors: Svorou Soteria
Published: February 2018

This study argues for a constructional account of the non-postural senses of
Modern Greek verb kaθοme ‘I sit’. Corpus data provide a
detailed account of the constructional pressures on kaθοme
as V1 in conjunctive coordination of verbs (V1 and
V2) and show that the non-postural senses emerge in
syntactically compact versions of the string with shared subject and
tense/aspect where locative adverbials and posture and disposition
adjectives, characteristic of the postural interpretations, never occur. In
such uses, the morphologically coded aspectual frame further determines a
deliberate action or an extended
duration interpretation framing V2 verbs, typically of mental
activity or communication. Pragmatic inferences tied to the construction
provide further motivation for considering the string a form-meaning
composite.
Traces of demonstrative grammaticalization in Spanish variable subject
expression
Authors: Torres Cacoullos Rena
Published: February 2018

Third person subject pronouns are widely hypothesized to arise from the
grammaticalization of demonstratives. Analysis of variation between
pronominal and unexpressed subjects in 13th–16th century Spanish texts
(N = 1,947) reveals that subjects referring to women
favored pronominal expression and were more sensitive to the syntactic role
of the previous mention. The data distribution shows that feminine referents
were less topical, or more deictically distant: they occurred less
frequently than masculine ones as subjects, and their previous mention was
more likely to have been in non-subject role – a particularly favorable
environment for pronoun ella ‘she’. Thus, as a vestige of
demonstrative origins, variable subject pronoun use could express
topicality. An intermediate stage of demonstrative > pronoun
grammaticalization may be use of the pronoun for unexpected
subjects.
Cumulative exposure to phonetic reducing environments marks the
lexicon
Authors: Brown Esther L.
Published: February 2018

Reduced pronunciation variants of words commonly arise in discourse contexts
promoting lenition. Words differ in their likelihood of occurrence in
reducing contexts. We test whether words’ cumulative exposure to reducing
environments significantly predicts phonological reduction in experimentally
elicited data. Cumulative exposure is measured as the proportion of times
words arise in phonetic contexts promoting reduced pronunciation variants
(FRC). Results of instrumental analyses of the 503 Spanish word-initial /d-/
tokens produced by 18 native speakers show significant correlations between
articulatory strength of the onset consonant (d-) and words’ production
histories (FRC), independent of the production context. Additionally, linear
modeling reveals a significant effect of FRC in predicting onset intensity.
Results suggest a cumulative effect on the lexicon of words’ production
histories.
Comparison of a 50 mL pycnometer and a 500 mL flask, EURAMET.M.FF.S8 (EURAMET 1297)
Authors: Mićić Ljiljana , Batista Elsa , Poenaru-Bordea Radu , Vámossy Csilla , Benkova Miroslava , Smits Erik , Sokolowska Beata , Niessner Anton , Grue Lise-Lotte , Malengo Andrea , Medina Nieves , Grum Matej , Piluri Erinda , Šarevska Anastazija , Mihailović Mirjana , Akcadag Umit
Published: February 2018

The purpose of this comparison was to compare the results of the participating laboratories in the calibration of 50 mL pycnometer and 500 mL volumetric flask using the gravimetric method.

Laboratories were asked to determined the 'contained' volume of the 50 mL pycnometer and of the 500 mL flask at a reference temperature of 20 °C. The gravimetric method was used for both instruments by all laboratories.

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