bluuebunny/crossref_metadata_2025 huggingface dataset:
On the microscopic fluctuations driving the NMR relaxation of quadrupolar ions in water
Authors: Carof Antoine , Salanne Mathieu , Charpentier Thibault , Rotenberg Benjamin
Published: November 2015

Nuclear Magnetic Resonance (NMR) relaxation is sensitive to the local structure and dynamics around the probed nuclei. The Electric Field Gradient (EFG) is the key microscopic quantity to understand the NMR relaxation of quadrupolar ions, such as 7Li+, 23Na+, 25Mg2+, 35Cl−, 39K+, or 133Cs+. Using molecular dynamics simulations, we investigate the statistical and dynamical properties of the EFG experienced by alkaline, alkaline Earth, and chloride ions at infinite dilution in water. Specifically, we analyze the effect of the ionic charge and size on the distribution of the EFG tensor and on the multi-step decay of its auto-correlation function. The main contribution to the NMR relaxation time arises from the slowest mode, with a characteristic time on the picosecond time scale. The first solvation shell of the ion plays a dominant role in the fluctuations of the EFG, all the more that the ion radius is small and its charge is large. We propose an analysis based on a simplified charge distribution around the ion, which demonstrates that the auto-correlation of the EFG, hence the NMR relaxation time, reflects primarily the collective translational motion of water molecules in the first solvation shell of the cations. Our findings provide a microscopic route to the quantitative interpretation of NMR relaxation measurements and open the way to the design of improved analytical theories for NMR relaxation for small ionic solutes, which should focus on water density fluctuations around the ion.
Controlling length-scales of the phase separation to optimize organic semiconductor blends
Authors: Lorch C. , Frank H. , Banerjee R. , Hinderhofer A. , Gerlach A. , Li Destri G. , Schreiber F.
Published: November 2015

The length-scale of phase separation in organic semiconductor donor-acceptor mixtures, while being crucially important for applications, is a non-trivial parameter to control in non-equilibrium thin film growth. We present a comprehensive study of all the important parameters that can be used to tailor the length-scale of phase separation in organic semiconductor mixtures. We employed different substrate temperatures, different growth rates, time-dependent deposition rates, and surface functionalization layers. We found not only that the substrate temperature is most prominent in influencing the length-scale of phase separation in the studied parameter range, but also that other routes can be used to tailor this length-scale.
Pairwise-additive force fields for selected aqueous monovalent ions from adaptive force matching
Authors: Li Jicun , Wang Feng
Published: November 2015

Simple non-polarizable potentials were developed for Na+, K+, Cl−, and Br− using the adaptive force matching (AFM) method with ab initio MP2 method as reference. Our MP2-AFM force field predicts the solvation free energies of the four salts formed by the ions with an error of no more than 5%. Other properties such as the ion-water radial distribution functions, first solvation shell water tilt angle distributions, ion diffusion constants, concentration dependent diffusion constant of water, and concentration dependent surface tension of the solutions were calculated with this potential. Very good agreement was achieved for these properties. In particular, the diffusion constants of the ions are within 6% of experimental measurements. The model predicts bromide to be enriched at the interface in the 1.6M KBr solution but predicts the ion to be repelled for the surface at lower concentration.
Measurement of heat load density profile on acceleration grid in MeV-class negative ion accelerator
Authors: Hiratsuka Junichi , Hanada Masaya , Kojima Atsushi , Umeda Naotaka , Kashiwagi Mieko , Miyamoto Kenji , Yoshida Masafumi , Nishikiori Ryo , Ichikawa Masahiro , Watanabe Kazuhiro , Tobari Hiroyuki
Published: November 2015

To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ∼16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles.
Shapes of dominant transition paths from single-molecule force spectroscopy
Authors: Makarov Dmitrii E.
Published: November 2015

Recent single molecule measurements of biomolecular folding achieved the time resolution sufficient for observation of individual transition paths. This note discusses several ways in which transition path ensembles can be statistically analyzed to extract a single, “typical” transition path. Analytical approximations derived here for such a transition path further allow one to estimate dynamical parameters (such as the intramolecular diffusion coefficient) directly from the transition path shapes.
Azimuthally polarized cathodoluminescence from InP nanowires
Authors: Brenny B. J. M. , van Dam D. , Osorio C. I. , Gómez Rivas J. , Polman A.
Published: November 2015

We determine the angle and polarization dependent emission from 1.75 µm and 2.50 µm long InP nanowires by using cathodoluminescence polarimetry. We excite the vertical wires using a 5 keV electron beam, and find that the 880 nm bandgap emission shows azimuthally polarized rings, with the number of rings depending on the wire height. The data agree well with a model in which spontaneous emission from the wire emitted into the far field interferes with emission reflected off the substrate. From the model, the depth range from which the emission is generated is found to be up to 400 nm below the top surface of the wires, well beyond the extent of the primary electron cloud. This enables a probe of the carrier diffusion length in the InP nanowires.
Magnetic properties of spin frustrated spinel ZnFe2O4/ZnCr2O4 superlattices
Authors: Murata T. , Kozuka Y. , Uchida M. , Kawasaki M.
Published: November 2015

Superlattice films composed of frustrated spin systems, [ZnFe2O4]m/[ZnCr2O4]m, are grown on MgAl2O4 (111) substrates by pulsed laser deposition, and their frustrated magnetism is studied. The superlattice films show spin-glass behavior and the spin-glass transition temperature (Tg) varies nonmonotonically as a function of the layer thickness m. Tg increases with decreasing m due to an increase in the inhomogeneous exchange interaction between Cr3+ and Fe3+ at the interface. However, below m = 4, a decrease in Tg is observed. Compared with the solid solution Zn(CrFe)O4 film and the other superlattices, the decrease in Tg is considered to be a unique property of the periodically modulated short period superlattices.
Direct subwavelength imaging and control of near-field localization in individual silver nanocubes
Authors: Mårsell Erik , Svärd Robin , Miranda Miguel , Guo Chen , Harth Anne , Lorek Eleonora , Mauritsson Johan , Arnold Cord L. , Xu Hongxing , L'Huillier Anne , Mikkelsen Anders , Losquin Arthur
Published: November 2015

We demonstrate the control of near-field localization within individual silver nanocubes through photoemission electron microscopy combined with broadband, few-cycle laser pulses. We find that the near-field is concentrated at the corners of the cubes, and that it can be efficiently localized to different individual corners depending on the polarization of the incoming light. The experimental results are confirmed by finite-difference time-domain simulations, which also provide an intuitive picture of polarization dependent near-field localization in nanocubes.
Probability of relativistic electron trapping by parallel and oblique whistler-mode waves in Earth's radiation belts
Authors: Artemyev A. V. , Vasiliev A. A. , Mourenas D. , Neishtadt A. I. , Agapitov O. V. , Krasnoselskikh V.
Published: November 2015

We investigate electron trapping by high-amplitude whistler-mode waves propagating at small as well as large angles relative to geomagnetic field lines. The inhomogeneity of the background magnetic field can result in an effective acceleration of trapped particles. Here, we derive useful analytical expressions for the probability of electron trapping by both parallel and oblique waves, paving the way for a full analytical description of trapping effects on the particle distribution. Numerical integrations of particle trajectories allow to demonstrate the accuracy of the derived analytical estimates. For realistic wave amplitudes, the levels of probabilities of trapping are generally comparable for oblique and parallel waves, but they turn out to be most efficient over complementary energy ranges. Trapping acceleration of <100 keV electrons is mainly provided by oblique waves, while parallel waves are responsible for the trapping acceleration of >100 keV electrons.
R-matrix, Lax pair, and multiparameter decompositions of Lie algebras
Authors: Dobrogowska Alina
Published: November 2015

We construct R operators on the Lie algebra 𝔤𝔩(n, ℝ) or more generally Hilbert–Schmidt operators L2 in Hilbert space. These operators are related to a multiparameter deformation given by a sequence of parameters α = {a1, a2, …}. We determine for which choices of parameters R operators are R-matrices. We also construct the Lax pair for the corresponding Hamilton equations.
Communication: Global flux surface hopping in Liouville space
Authors: Wang Linjun , Sifain Andrew E. , Prezhdo Oleg V.
Published: November 2015

Recent years have witnessed substantial progress in the surface hopping (SH) formulation of non-adiabatic molecular dynamics. A generalization of the traditional fewest switches SH (FSSH), global flux SH (GFSH) utilizes the gross population flow between states to derive SH probabilities. The Liouville space formulation of FSSH puts state populations and coherences on equal footing, by shifting the hopping dynamics from Hilbert to Liouville space. Both ideas have shown superior results relative to the standard FSSH in Hilbert space, which has been the most popular approach over the past two and a half decades. By merging the two ideas, we develop GFSH in Liouville space. The new method is nearly as straightforward as the standard FSSH, and carries comparable computational expense. Tested with a representative super-exchange model, it gives the best performance among all existing techniques in the FSSH series. The obtained numerical results match almost perfectly the exact quantum mechanical solutions. Moreover, the results are nearly invariant under the choice of a basis state representation for SH, in contrast to the earlier techniques which exhibit notable basis set dependence. Unique to the developed approach, this property is particularly encouraging, because exact quantum dynamics is representation independent. GFSH in Liouville space significantly improves accuracy and applicability of SH for a broad range of chemical and physical processes.
Effect of crystallization water on the structural and electrical properties of CuWO4 under high pressure
Authors: Wang Li , Ke Feng , Wang Qinglin , Yan Jiejuan , Liu Cailong , Liu Xizhe , Li Yanchun , Han Yonghao , Ma Yanzhang , Gao Chunxiao
Published: November 2015

The effect of crystallization water on the structural and electrical properties of CuWO4 under high pressure has been investigated by in situ X-ray diffraction and alternating current impedance spectra measurements. The crystallization water was found to be a key role in modulating the structural stability of CuWO4 at high pressures. The anhydrous CuWO4 undergoes two pressure-induced structural transitions at 8.8 and 18.5 GPa, respectively, while CuWO4·2H2O keeps its original structure up to 40.5 GPa. Besides, the crystallization water makes the electrical transport behavior of anhydrous CuWO4 and CuWO4·2H2O quite different. The charge carrier transportation is always isotropic in CuWO4·2H2O, but anisotropic in the triclinic and the third phase of anhydrous CuWO4. The grain resistance of CuWO4·2H2O is always larger than that of anhydrous CuWO4 in the entire pressure range. By analyzing the relaxation response, we found that the large number of hydrogen bonds can soften the grain characteristic frequency of CuWO4·2H2O over CuWO4 by one order of magnitude.
A Monte Carlo simulation for bipolar resistive memory switching in large band-gap oxides
Authors: Hur Ji-Hyun , Lee Dongsoo , Jeon Sanghun
Published: November 2015

A model that describes bilayered bipolar resistive random access memory (BL-ReRAM) switching in oxide with a large band gap is presented. It is shown that, owing to the large energy barrier between the electrode and thin oxide layer, the electronic conduction is dominated by trap-assisted tunneling. The model is composed of an atomic oxygen vacancy migration model and an electronic tunneling conduction model. We also show experimentally observed three-resistance-level switching in Ru/ZrO2/TaOx BL-ReRAM that can be explained by the two types of traps, i.e., shallow and deep traps in ZrO2.
Electronic transport in methylated fragments of DNA
Authors: de Almeida M. L. , Oliveira J. I. N. , Lima Neto J. X. , Gomes C. E. M. , Fulco U. L. , Albuquerque E. L. , Freire V. N. , Caetano E. W. S. , de Moura F. A. B. F. , Lyra M. L.
Published: November 2015

We investigate the electronic transport properties of methylated deoxyribonucleic-acid (DNA) strands, a biological system in which methyl groups are added to DNA (a major epigenetic modification in gene expression), sandwiched between two metallic platinum electrodes. Our theoretical simulations apply an effective Hamiltonian based on a tight-binding model to obtain current-voltage curves related to the non-methylated/methylated DNA strands. The results suggest potential applications in the development of novel biosensors for molecular diagnostics.
Exciton dynamics in perturbed vibronic molecular aggregates
Authors: Brüning C. , Wehner J. , Hausner J. , Wenzel M. , Engel V.
Published: November 2015

A site specific perturbation of a photo-excited molecular aggregate can lead to a localization of excitonic energy. We investigate this localization dynamics for laser-prepared excited states. Changing the parameters of the electric field significantly influences the exciton localization which offers the possibility for a selective control of this process. This is demonstrated for aggregates possessing a single vibrational degree of freedom per monomer unit. It is shown that the effects identified for the molecular dimer can be generalized to larger aggregates with a high density of vibronic states.
Controllable magnetization and resistivity jumps of manganite thin films on BaTiO3 substrate
Authors: Wei Wengang , Chen Jinjie , Zhang Kai , Kou Yunfang , Du Kai , Zhu Yinyan , Wang Wenbin , Li Xiaolong , Zhang Xingmin , Gao Xingyu , Zhang Lei , Tian Mingliang , Hou Denglu , Yin Lifeng , Shen Jian
Published: November 2015

Manganites thin films grown on ferroelectric BaTiO3 (BTO) exhibit dramatic jumps for both magnetization and resistivity upon cooling in accordance with the temperature-dependent structural transitions of the BTO substrate. Both upward and downward jumps have been reported at the same temperature point where BTO undergoes a structural transition from monoclinic to rhombohedral. Using La5/8Ca3/8MnO3/BaTiO3 as protype system, we solve the puzzle by showing that the direction of the jumps can be controlled by applying an electric field during post growth cooling which determines the orientation of the c-axis of the BTO substrate at room temperature. This offers a convenient way to control the magnetic and transport behavior of manganites films using electric field.
A comparison of level set and marker methods for the simulation of wildland fire front propagation
Authors: Bova Anthony S. , Mell William E. , Hoffman Chad M.
Published: November 2015

Simulating an advancing fire front may be achieved within a Lagrangian or Eulerian framework. In the former, independently moving markers are connected to form a fire front, whereas in the latter, values representing the moving front are calculated at points within a fixed grid. Despite a mathematical equivalence between the two methods, it is not clear that both will produce the same results when implemented numerically. Here, we describe simulations of fire spread created using a level set Eulerian approach (as implemented in the wildland–urban interface fire dynamics simulator, WFDS) and a marker method (as implemented in FARSITE). Simulations of surface fire spread, in two different fuels and over domains of increasing topographical complexity, are compared to evaluate the difference in outcomes between the two models. The differences between the results of the two models are minor, especially compared with the uncertainties inherent in the modelling of fire spread.
Climate and topography control the size and flux of sediment produced on steep mountain slopes
Authors: Riebe Clifford S. , Sklar Leonard S. , Lukens Claire E. , Shuster David L.
Published: November 2015

Significance

Rivers carve through landscapes using sediment produced on hillslopes by biological, chemical, and physical weathering of underlying bedrock. Both the size and supply rate of sediment influence the pace of river incision and landscape evolution, but the connections remain poorly understood, because the size distributions of sediment supplied from slopes have been difficult to quantify. This study combined existing sediment-tracing techniques in a previously unidentified approach to quantify sediment production across an alpine catchment in the High Sierra, California. Results show that colder, steeper, and less vegetated slopes produce coarser sediment that erodes faster into the channel network. These results demonstrate that the sediment-tracing approach can be used to quantify feedbacks between climate, topography, and erosion.
Ammonite habitat revealed via isotopic composition and comparisons with co-occurring benthic and planktonic organisms
Authors: Sessa Jocelyn Anne , Larina Ekaterina , Knoll Katja , Garb Matthew , Cochran J. Kirk , Huber Brian T. , MacLeod Kenneth G. , Landman Neil H.
Published: November 2015

Significance

Because ammonites are one of the most diverse, abundant, and well-preserved clades in the history of life, they are a mainstay in macroevolutionary and biodiversity studies; however, their ecologies are poorly understood, and it is unknown whether taxa lived near the sea surface or seafloor. This uncertainty undermines their use in paleoecological and paleoenvironmental reconstructions, which depend on knowledge of organisms’ depth preferences. Here, we use a rare co-occurrence of exquisitely well-preserved ammonites and planktonic and benthic organisms to constrain depth preferences of three common ammonite families by comparing the oxygen and carbon isotopic signatures of these taxa. The ammonites fall into two distinct depth habitats, enhancing the utility of these families for highly refined paleoecological and paleoclimatic studies.
A meningococcal vaccine antigen engineered to increase thermal stability and stabilize protective epitopes
Authors: Konar Monica , Pajon Rolando , Beernink Peter T.
Published: November 2015

Significance

Factor H binding protein (FHbp) is a component of two vaccines recently licensed for prevention of sepsis and meningitis caused by meningococci. FHbp is antigenically variable, and certain sequence variants have low thermal stability. Two amino acid substitutions stabilized a less stable FHbp variant by 21 °C, and the high-resolution crystal structure of the stabilized FHbp antigen showed that the two new residues mediated multiple electrostatic interactions. The two substitutions increased the affinity for monoclonal antibodies specific for different regions of FHbp and increased binding to the mutant expressed on the surface of meningococci. The stabilized FHbp antigen has the potential to improve the immunogenicity of meningococcal vaccines containing recombinant FHbp or native outer membrane vesicles.
Upper atmospheric gravity wave details revealed in nightglow satellite imagery
Authors: Miller Steven D. , Straka William C. , Yue Jia , Smith Steven M. , Alexander M. Joan , Hoffmann Lars , Setvák Martin , Partain Philip T.
Published: November 2015

Significance

As an unforeseen windfall of its high sensitivity, the Day/Night Band (DNB) low-light visible sensor carried on the Suomi satellite enables global detection of gravity waves in the upper atmosphere at unprecedented subkilometric detail. On moonless nights, the observations provide all-weather viewing of waves as they modulate the nightglow layer located near the mesopause. These waves are launched by a variety of mechanisms ranging from orography to convection, intensifying fronts, and seismic and volcanic events. Wave energy is recognized as the principal driver of upper atmospheric circulation, which in turn influences tropospheric weather patterns. For lack of global observations, information about upper atmospheric wave distribution and character is limited. Here, the DNB begins to fill a critical gap.
Resting-state functional connectivity predicts longitudinal change in autistic traits and adaptive functioning in autism
Authors: Plitt Mark , Barnes Kelly Anne , Wallace Gregory L. , Kenworthy Lauren , Martin Alex
Published: November 2015

Significance

Few individuals diagnosed with autism spectrum disorder (ASD) go on to achieve high levels of independence or what are considered “very good” outcomes. As such, there is a need to identify predictors of outcomes to improve treatment and services for these individuals. Although behavioral and cognitive variables can predict substantial variance in outcomes, the majority of the variance remains unexplained. In this study, we investigated whether a measure of intrinsic functional brain connectivity [resting-state functional connectivity MRI (rs-fcMRI)] could add meaningful predictive power. Indeed, we found that connectivity involving several brain networks previously implicated in ASD could predict improvements in adaptive behaviors several years after the scan with a high degree of sensitivity.
Identification and characterization of functional homologs of nitrogenase cofactor biosynthesis protein NifB from methanogens
Authors: Fay Aaron W. , Wiig Jared A. , Lee Chi Chung , Hu Yilin
Published: November 2015

Significance

Nitrogenase biosynthesis protein NifB catalyzes the radical
S
-adenosyl-L-methionine (SAM)-dependent insertion of carbide into the nitrogenase cofactor, M cluster, in a chemically unprecedented and biologically important reaction. The observation that two naturally “truncated” NifB homologs from
Methanosarcina acetivorans
(NifB

Ma

) and
Methanobacterium thermoautotrophicum
(NifB

Mt

) are functional equivalents of NifB from the diazotrophic organism,
Azotobacter vinelandii
, establishes the minimum sequence requirement for a functional NifB protein and reveals the species-dependent difference between members of this protein family; more importantly, it leads to the categorization of a distinct class of radical SAM methyltransferases that function in complex metallocluster assembly while opening up new avenues to study the structure and mechanism of NifB.
The structural kinetics of switch-1 and the neck linker explain the functions of kinesin-1 and Eg5
Authors: Muretta Joseph M. , Jun Yonggun , Gross Steven P. , Major Jennifer , Thomas David D. , Rosenfeld Steven S.
Published: November 2015

Significance

The kinesins are molecular motors that couple ATP binding to movement. Although crystallographic and cryo-EM methods have identified the structural changes that occur in several kinesins, the images they generate are static pictures that provide no insight into how dynamic these conformations are or how they are coupled together to generate force. We have addressed this through a novel combination of time-resolved fluorescence and transient-state kinetics to measure the conformational equilibria between two key domains in two functionally distinct kinesins: kinesin-1 and Eg5. Our results are significant because they provide a unique insight into how conformational dynamics vary between two kinesins with different functions, and explain the distinct enzymologies these two kinesins have.
Relaxed genetic control of cortical organization in human brains compared with chimpanzees
Authors: Gómez-Robles Aida , Hopkins William D. , Schapiro Steven J. , Sherwood Chet C.
Published: November 2015

Significance

Despite decades of research, we still have a very incomplete understanding of what is special about the human brain compared with the brains of our closest fossil and living relatives. Parsing the genetic versus environmental factors that govern the structure of the cerebral cortex in humans and chimpanzees may shed light on the evolution of behavioral flexibility in the human lineage. We show that the morphology of the human cerebral cortex is substantially less genetically heritable than in chimpanzees and therefore is more responsive to molding by environmental influences. This anatomical property of increased plasticity, which is likely related to the human pattern of development, may underlie our species’ capacity for cultural evolution.
Mitochondrial functions modulate neuroendocrine, metabolic, inflammatory, and transcriptional responses to acute psychological stress
Authors: Picard Martin , McManus Meagan J. , Gray Jason D. , Nasca Carla , Moffat Cynthia , Kopinski Piotr K. , Seifert Erin L. , McEwen Bruce S. , Wallace Douglas C.
Published: November 2015

Significance

In humans and animals, stress triggers multisystemic physiological responses that vary in nature and magnitude. The organism’s response to stress, rather than actual stressors, leads to allostatic load that predisposes to disease. This study in mice demonstrates that a specific cellular component that sustains life via energy transformation and intracellular signaling—the mitochondrion—influences the organism’s integrated response to psychological stress. Each component of the stress response assessed was modified by at least one mitochondrial defect. When analyzed collectively, stress-induced neuroendocrine, inflammatory, metabolic, and transcriptional responses coalesced into unique signatures that distinguish groups based on their mitochondrial genotype. This work shows that mitochondria can regulate complex whole-body physiological responses, impacting stress perception at the cellular and organismal levels.
Proline-, glutamic acid-, and leucine-rich protein 1 mediates estrogen rapid signaling and neuroprotection in the brain
Authors: Sareddy Gangadhara R. , Zhang Quanguang , Wang Ruimin , Scott Erin , Zou Yi , O'Connor Jason C. , Chen Yidong , Dong Yan , Vadlamudi Ratna K. , Brann Darrell
Published: November 2015

Significance

Ever since the rapid extranuclear signaling effects of 17β-estradiol (E2) were first identified in the brain decades ago, it has remained an enigma as to how these nonclassical effects are achieved. Using a forebrain-specific knockout animal model, the current study demonstrates that a recently cloned estrogen receptor coregulator protein, Proline-, glutamic acid-, and leucine-rich protein 1 (PELP1), is critical for mediating E2 regulation of rapid extranuclear signaling, as well as E2-induced neuroprotection and cognitive function in the hippocampus after ischemic injury. Our studies also identified PELP1 as a novel interacting protein and a substrate of glycogen synthase kinase-3β (GSK3β). Finally, PELP1 was also shown to mediate E2 genomic effects to regulate genes involved in inflammation, metabolism, and survival after ischemic injury.
Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism
Authors: Fan Tingting , Grychtol Patrik , Knut Ronny , Hernández-García Carlos , Hickstein Daniel D. , Zusin Dmitriy , Gentry Christian , Dollar Franklin J. , Mancuso Christopher A. , Hogle Craig W. , Kfir Ofer , Legut Dominik , Carva Karel , Ellis Jennifer L. , Dorney Kevin M. , Chen Cong , Shpyrko Oleg G. , Fullerton Eric E. , Cohen Oren , Oppeneer Peter M. , Milošević Dejan B. , Becker Andreas , Jaroń-Becker Agnieszka A. , Popmintchev Tenio , Murnane Margaret M. , Kapteyn Henry C.
Published: November 2015

Significance

The new ability to generate circularly polarized coherent (laser-like) beams of short wavelength high harmonics in a tabletop-scale setup is attracting intense interest worldwide. Although predicted in 1995, this capability was demonstrated experimentally only in 2014. However, all work to date (both theory and experiment) studied circularly polarized harmonics only in the extreme UV (EUV) region of the spectrum at wavelengths >18 nm. In this new work done in a broad international collaboration, we demonstrate the first soft X-ray high harmonics with circular polarization to wavelengths
λ
< 8 nm and the first tabletop soft X-ray magnetic circular dichroism (XMCD) measurements, and also uncover new X-ray light science that will inspire many more studies of circular high-harmonic generation (HHG).
Nuclear and mitochondrial DNA sequences from two Denisovan individuals
Authors: Sawyer Susanna , Renaud Gabriel , Viola Bence , Hublin Jean-Jacques , Gansauge Marie-Theres , Shunkov Michael V. , Derevianko Anatoly P. , Prüfer Kay , Kelso Janet , Pääbo Svante
Published: November 2015

Significance

Denisovans are a sister group of Neandertals that were identified on the basis of a nuclear genome sequence from a bone from Denisova Cave (Siberia). The only other Denisovan specimen described to date is a molar from the same site. We present here nuclear DNA sequences from this molar and a morphological description, as well as mitochondrial and nuclear DNA sequences from another molar from Denisova Cave, thus extending the number of Denisovan individuals known to three. The nuclear DNA sequence diversity among the Denisovans is higher than among Neandertals, but lower than among present-day humans. The mtDNA of one molar has accumulated fewer substitutions than the mtDNAs of the other two specimens, suggesting Denisovans were present in the region over several millennia.
Synthetic CRISPR RNA-Cas9–guided genome editing in human cells
Authors: Rahdar Meghdad , McMahon Moira A. , Prakash Thazha P. , Swayze Eric E. , Bennett C. Frank , Cleveland Don W.
Published: November 2015

Significance

Genome editing with nucleases that recognize specific DNA sequences is a powerful technology for manipulating genomes. This is especially true for the Cas9 nuclease, the site specificity of which is determined by a bound RNA, called a CRISPR RNA (crRNA). Here we develop a chemically modified, 29-nucleotide synthetic CRISPR RNA (scrRNA) and show that it can functionally replace the natural crRNA, producing enhanced cleavage activity at a target DNA site with apparently reduced off-target cleavage. scrRNAs can be synthesized in a commercially feasible manner today and provide a platform for therapeutic applications.
Renegotiating the empire, forging the nation-state: The Georgian case through the political economic thought of Niko Nikoladze and Noe Zhordania, c. 1870-1920
Authors: Brisku Adrian
Published: November 2015

This article begins with an observation of a contemporary and yet reoccurring political dilemma that small nation-states face with respect to larger states in being either inside or outside of supranational political entities regarding political and economic asymmetries. Employing an intellectual history approach, the article explores this dilemma with reference to the Georgian nation in late-nineteenth century Tsarist Russia and the early twentieth century, when that territory briefly became a nation-state: It explores this through the language of political economy articulated in the thoughts and actions of two founding Georgian national intellectual and political figures, the statesman Niko Nikoladze and Noe Zhordania, who was one of the first prime ministers. It argues that conceiving of the nation(state) primarily in economic terms, as opposed to exclusively nationalist ones, was more conducive to the option of remaining inside a supranational space.
Investment Age and Dynamic Productivity Growth in the Spanish Food Processing Industry
Authors: Kapelko Magdalena , Oude Lansink Alfons , Stefanou Spiro E.
Published: November 2015

This article analyzes the relation between investment age, measured as the number of years since investment spike, and dynamic productivity growth and its components, which include dynamic technical change, dynamic inefficiency change, and dynamic scale inefficiency change. The empirical application focuses on firm‐level data for the Spanish food processing industry covering the period from 1996 to 2011. This investigation of the impact of firms' investment decisions on productivity growth employs a dynamic production framework and analyzes the impact of these decisions on the components of dynamic productivity growth. Our findings show that dynamic productivity growth is negatively affected by investment spikes in both the meat processing and oils and fats industries, and that dynamic inefficiency change initially falls just after the infusion of large investment for oils and fats firms, but then grows as the firms acquire experience with this investment. We further find that investment spikes lead to improvements in dynamic technical change and worsening in dynamic technical inefficiency change in the meat processing industry, while dynamic scale inefficiency change was negatively impacted in both industries.
Generalist Practice and Advanced Generalist Practice
Authors: Rooney Ronald , Der Vang Pa
Published: November 2015

Generalist practice is at the foundation of social work’s attention to multiple systems utilizing multiple methods toward goals of empowerment, attention to diversity, and social and economic justice. It is often framed as the foundation of social work education and is found at the baccalaureate level. Advanced generalist practice refers to graduate-level generalist social work education and practice. It implies a deeper level of study and fine tuning of generalist skills that still focuses on the practitioner’s ability to work across different settings, with different populations, and in different contexts without specificity of one particular practice model or theory.
Second Clement
Authors: Pratscher Wilhelm
Published: November 2015

The text of 2 Clement (2 Clem) has only survived in three manuscripts. The oldest one, the Codex Alexandrinus (A), ends at 12.5, the complete Greek text can be found in the Codex Hierosolymitanus (H), which dates back to 1056 ce. The third version can be found in a Syrian translation from 1170 ce. In all three documents, 2 Clem has come down to us in connection with 1 Clem, although it is not a letter but a sermon, more precisely: it is a hortatory address. The whole text deals with parenesis. Chapters 1–3 are dominated by Christological argumentation, in chapters 4–18 the eschatological argumentation has priority. Chapters 19f are a secondary supplement, which probably served as an introduction to chapters 1–18, the original sermon. This can be concluded from linguistic and factual aspects. The author is unknown. He is definitely not the author of 1 Clem, which can be concluded from numerous linguistic differences as well as from different theological views. The assumed opponents are most probably to be found in the context of the emergent Gnosticism, but the author does not focus on a direct confrontation with these opponents. Possible places of origin are Rome, Corinth, Antioch, and Alexandria. In the recent research, Alexandria seems to gain more and more acceptance, based especially on the fact that the author is familiar with Egyptian traditions of his time. It is highly probable that the text was written around 150 ce, and 2 Clem shows that the author is acquainted with the traditions of the Old and New Testaments. Concerning Christian traditions, it can be assumed that he was familiar with the Gospels of Matthew and Luke, but there is no definite proof of this. In addition to texts, which can later be found in canonical documents, 2 Clem also makes use of apocryphal traditions or texts. The formation of the canon was not yet finished at this time. The basic aim of 2 Clem is parenesis. The focus is on the goal to organize life in Christian faith appropriately. Theological topics are oriented toward this goal. God is a creator and a savior. In his Christology, the author holds the opinion that Jesus is preexistent. It may strike us as remarkable that the author, who is traditionally seen as anti-Gnostic, does not estimate pneumatology as important to his audience. Newer publications (cf. Tuckett and Kelhoffer) oppose the view, that 2 Clement is anti-Gnostic. The connection between Christ and the church is expressed with the help of syzygies; and interestingly, in this connection the author pleads for the preexistence of the church. In his eschatology, the future version is predominant. Realized eschatological statements can be found only implicitly.
Tīrtha
Authors: Jacobsen Knut Axel
Published: November 2015

In Hindu traditions, a tīrtha is a place believed to possess auspiciousness and purifying, salvific power, and it is therefore a pilgrimage site, tīrthayātrā. The term tīrtha is widely used for pilgrimage place, but pīṭha is also common, especially in tantric traditions about pilgrimage places associated with goddesses. Some pilgrimage places are called dhāms, such as the Himalayan pilgrimage to the four dhāms Badrinath, Kedarnath, Yamunotri, and Gangotri. Rivers are also objects of pilgrimage. The term kṣetra is also used for pilgrimage places, often for pilgrimage places that contain many tīrthas pilgrims are supposed to visit. Many Hindu pilgrimage places are associated with water since bathing often is part of the rituals performed at the pilgrimage places. Visiting tīrthas is a dominant feature of Hindu traditions, but pilgrimage was not part of the religion of the Vedas. The earliest Sanskrit text to promote visits to tīrthas was the Mahābhārata. The long Tīrthayātrāparvan, which constitutes chapters 78–148 of the Vanaparvan of the Mahābhārata, is perhaps from 200 to 400 ce or later. Cultural and social changes in this period led to tīrthas being increasingly promoted by bards and Brahmans. The genre of the Purāṇas was created to promote new religious ideas and practices and is dominated by the ideology of salvific space and promotion of pilgrimage travel to tīrthas. The Purāṇas contain a large number of Māhātmyas (texts proclaiming the greatness of a place), and many Purāṇas are themselves Māhātmyas of place, Sthalapurāṇas. The sacred narratives of the Purāṇas are often connected to places. In the Hindu traditions, the landscapes are adorned with narratives of gods and goddesses. For most Hindus, tīrthas have been more important than religious books, especially until the ability to read became widespread. Economic change seems to have played an important role in the development of salvific places and economic interests have been important motivations for their promotion. The salvific rewards granted by visits to the sites were often associated with gifts to Brahmans, which indicates the importance of the economic dimension in the pilgrimage tradition. Typically, in the texts promoting pilgrimage places, the salvific rewards of visiting pilgrimage centers are exaggerated, and the rewards of the Vedic sacrifices ridiculed, which probably points to conflicts in the tradition between different groups of priests. In the Hindu traditions, salvific space is a process, a way to relate to the environment, and new places of pilgrimage are continuously being created.
Institutions
Authors: Berardo Ramiro , Hanlon Jeffrey W.
Published: November 2015

There is widespread consensus among environmental scientists that a holistic understanding of how natural resources are managed effectively at different scales requires a solid grasp on the functioning of governance institutions that link human users to the biophysical world in which they are embedded. Societies exist within complex social-ecological systems, in which the social and ecological components are tightly connected in systematic, but often hard to understand, ways. Institutions are, in essence, the lubricant that mediates the relationship between the two components; without the right institutions in place, no human society can tackle environmental problems successfully. Needless to say, the variation of societies and ecological systems around the world is vast and rich, which makes the study of institutional diversity and its effect on the management of natural resources both fascinating and daunting. From the rules to manage small-scale indigenous fisheries to the treaties to tackle global climate change, humans craft and enforce institutions to avoid “tragedies of the commons” that result when the prevalence of individual interests leads to the mismanagement (and sometimes sheer complete destruction) of resources that are open to multiple users. This article serves as an introductory guide for scholars and students with an interest in understanding how social scientists have researched institutions and their role in constraining human behavior in search of sustainable uses of natural resources. Sections cover research focusing on the definition, creation, development, evolution, and performance of institutions, as well as the operation of institutions at different scales and in different topic areas.
John Ford
Authors: Schnioffsky Ross , Thompson Richard
Published: November 2015

John Ford’s film career began with the earliest days of Hollywood silent filmmaking c. 1914 and continued until 1968, spanning the rise of the studio system, the coming of sound and color, the postwar restructuring of the studio system in the face of the antitrust decision, television, and rapid expansion of independent production. The industry awarded him four Academy Awards for direction and two for documentaries, an unsurpassed record. In 1935, his film The Informer was influentially seen as an example that the US film industry could produce film art to equal the Europeans. At this time he was actively involved in the formation of the Directors Guild of America. In 1939, Stagecoach elevated the western genre to A-picture respectability (and made John Wayne a major star). During the same remarkable two-year period (1939–1941), Ford made Young Mr. Lincoln (1939), Drums Along the Mohawk (1939), The Grapes of Wrath (1940), and How Green Was My Valley (1941). In following years, his work attracted serious attention from Andre Bazin, Sergei Eisenstein, Lindsay Anderson, Orson Welles, Jean Renoir, and others. Ford’s worldview and subject matter were beginning to be seen as deeply concerned with American history and myth. Ford is now regarded by many as a major American storyteller. During World War II, he headed a documentary film unit for the US government, seeing frontline active service in Europe and the Pacific. Following the war, his Hollywood films took on a darker, elegiac tone, notably—but not limited to—the cavalry trilogy, The Searchers (1956), The Man Who Shot Liberty Valance (1962), and 7 Women (1966). As Ford’s thinking changed during this period, so did thinking about Ford: particularly in France, then Britain and the United States, a serious film study culture was developing, annexing critical methods and analytic concepts from older established disciplines and arts. From this rose auteurism—authorship theory—and mise-en-scène analysis. Ford was quickly inducted into the pantheon of major film directors (not, of course, without some controversy). Social and political wings of film thought examined Ford’s changing representation of Native Americans and other races and ethnics; gender (women, masculinity, sexuality); class differences; character types and construction; his populism and its attendant irony and comedy; and increasingly, visual style. Since the 1960s, the development of serious film studies can be measured by the development and changes in their presentation of the case of John Ford. In the 1970s and 1980s, a new generation of filmmakers, critics, and scholars removed Citizen Kane (1941) from its long-held, solitary position as The Great American Film, giving The Searchers equal status.
Celtic and Irish Revival
Authors: McAteer Michael
Published: November 2015

The phrase Celtic Revival describes past movements in literature, the arts, and social practices in which legends, poetry, art, and spirituality of a distinctive kind were revived. Writers and artists identified these with the Celtic people in parts of pre-Christian and early Christian Europe. The most significant Celtic Revival took place in Ireland toward the end of the 19th century and into the first two decades of the 20th century. It is commonly referred to as the Irish Revival, though it has also been considered a Celtic revival in Ireland that had associations with revival movements in Scotland, Wales, the English regions, and Brittany. The Irish Revival was felt most strongly in literature, drama, and the Irish language. It was also evident in art, design, music, and sport. The political and economic features of the Irish Revival were complex. The influence of militant nationalism was strong, yet unionist, Home Rule nationalist, socialist, and feminist political views were held by different figures involved in the Irish Revival across a range of different groups and activities. Much academic scholarship concerned with Celtic Revival has focused on the literary and dramatic movement in Ireland, producing as it did three of the most important international literary figures of the 20th century—W. B. Yeats, J. M. Synge, and Sean O’Casey. The term Celtic Revival, however, was contested by some cultural activists in Ireland. During the Irish Revival, some regarded the notion of “Celtic” Revival as softening the national “Irish” nature of the movement, implying affinities with the ancient inheritances of England, Scotland, and Wales, its focus more among literary societies in London than among those engaged in “nation-building” activities in Dublin. For others, the Celtic aspect of the Irish Revival was precisely what distinguished it from the modern character of English urban society. Aside from this, the question arises as to how much Celtic Revival in Ireland and Britain grew out of inventions of the Celt as a cultural ideal from the 16th century in Europe. This article opens with a section covering studies of Celtic civilization in Ireland and Britain. Subsequent sections address scholarship on the literary and dramatic aspects of the Irish Revival from the late 19th century, its historical contexts, as well as the range of its political ideas, movements, and activists. Academic publications are also listed on a range of individual literary and language-revival figures associated with the Irish Revival. Later sections cover studies of Pan-Celticism and Celtic Revival in Britain. The final sections identify scholarship on the Irish Revival in the fields of art, design, music, and sport, addressing correspondences between activities in Celtic revival in Ireland and Scotland in the process.