bluuebunny/crossref_metadata_2025 huggingface dataset:
Band gap and defect state engineering in a multi-stub phononic crystal plate
Authors: Jiang Ping , Wang Xiao-Peng , Chen Tian-Ning , Zhu Jian
Published: April 2015

In this paper, we investigated the characteristics of band gaps and defect states in a locally resonant phononic crystal structure consisting of multiple square stubs deposited on both sides of a thin homogeneous plate. Using the finite element method and supercell technique, we calculated the dispersion relationships and power transmission spectra of this structure, which agree well with each other. This structure offers wide band gaps at extremely low frequencies. Moreover, we investigated how the band gaps are affected by the distance between two adjacent square stubs, finding that acoustic band gaps are very sensitive to the distance between two adjacent square stubs, a property important for practical applications. Based on this finding, we proposed a novel method to form phononic crystal structure defect: Defect bands can be induced by creating defects inside the original complete band gaps. The frequency can then be tuned by changing the distance between two adjacent square stubs of the defect scatterer. These results will help in fabricating devices, such as acoustic filters and waveguides whose band frequency can be modulated.
A dedicated compression device for high resolution X-ray tomography of compressed gas diffusion layers
Authors: Tötzke C. , Manke I. , Gaiselmann G. , Bohner J. , Müller B. R. , Kupsch A. , Hentschel M. P. , Schmidt V. , Banhart J. , Lehnert W.
Published: April 2015

We present an experimental approach to study the three-dimensional microstructure of gas diffusion layer (GDL) materials under realistic compression conditions. A dedicated compression device was designed that allows for synchrotron-tomographic investigation of circular samples under well-defined compression conditions. The tomographic data provide the experimental basis for stochastic modeling of nonwoven GDL materials. A plain compression tool is used to study the fiber courses in the material at different compression stages. Transport relevant geometrical parameters, such as porosity, pore size, and tortuosity distributions, are exemplarily evaluated for a GDL sample in the uncompressed state and for a compression of 30 vol.%. To mimic the geometry of the flow-field, we employed a compression punch with an integrated channel-rib-profile. It turned out that the GDL material is homogeneously compressed under the ribs, however, much less compressed underneath the channel. GDL fibers extend far into the channel volume where they might interfere with the convective gas transport and the removal of liquid water from the cell.
Novel magnetic and optical properties of Sn1−xZnxO2 nanoparticles
Authors: Franco Nevil A. , Reddy Kongara M. , Eixenberger Josh , Tenne Dmitri A. , Hanna Charles B. , Punnoose Alex
Published: April 2015

In this work, we report on the effects of doping SnO2 nanoparticles with Zn2+ ions. A series of ∼2–3 nm sized Sn1−xZnxO2 crystallite samples with 0 ≤ x ≤ 0.18 were synthesized using a forced hydrolysis method. Increasing dopant concentration caused systematic changes in the crystallite size, oxidation state of Sn, visible emission, and band gap of SnO2 nanoparticles. X-ray Diffraction studies confirmed the SnO2 phase purity and the absence of any impurity phases. Magnetic measurements at room temperature showed a weak ferromagnetic behavior characterized by an open hysteresis loop. Their saturation magnetization Ms increases initially with increasing Zn concentrations; however for x > 0.06, Ms decreases. Samples with the highest Ms values (x = 0.06) were analyzed using an Inductively Coupled Plasma Mass Spectrometer, looking for traces of any magnetic elements in the samples. Concentrations of all transition metals (Fe, Co, Mn, Cr, and Ni) in these samples were below ppb level, suggesting that the observed magnetism is not due to random inclusions of any spurious magnetic impurities and it cannot be explained by the existing models of magnetic exchange. A new visible emission near 490 nm appeared in the Zn doped SnO2 samples in the photoluminescence spectra which strengthened as x increased, suggesting the formation of defects such as oxygen vacancies. X-ray Photoelectron Spectroscopy (XPS) confirmed the nominal Zn dopant concentrations and the 2+ oxidation state of Zn in the Sn1−xZnxO2 samples. Interestingly, the XPS data indicated the presence of a small fraction of Sn2+ ions in Sn1−xZnxO2 samples in addition to the expected Sn4+, and the Sn2+ concentration increased with increasing x. The presence of multi-valent metal ions and oxygen defects in high surface area oxide nanoparticles has been proposed as a potential recipe for weak ferromagnetism (Coey et al., New J. Phys. 12, 053025 (2010)).
Magnetic hardening of Ce1+xFe11−yCoyTi with ThMn12 structure by melt spinning
Authors: Zhou Chen , Sun Kewei , Pinkerton Frederick E. , Kramer M. J.
Published: April 2015

A recent study on the intrinsic magnetic properties of CeFe11−yCoyTi has revealed that substituting one Co for Fe retains the favorable magnetocrystalline anisotropy Ha found in the ternary Fe end member, while enhancing the Curie temperature Tc and saturation magnetization 4πMs. These findings warrant further optimization around Co substitution y = 1 to try to exploit the hard magnetic properties of these Ce-based magnets. Both Ce and Co concentrations in Ce1+xFe11−yCoyTi have been optimized in the range of x = 0 − 0.2 and y = 0 − 1.5. It was found that Co substitution effectively enhances all hard magnetic properties, although the values are still lower than those predicted from the intrinsic magnetic properties. Specifically, Tc increases from 210 °C to 285–350 °C; 4πM19 (magnetization at 19 kOe) from 8.9 kG to 10.5–11.5 kG, remanence Br from 3.1 kG to 4.1–4.5 kG, and most importantly, Hci from 1.1 kOe to 1.5 kOe. As a result, the room temperature energy product (BH)max has been increased by over 100% from 0.7 MGOe in Ce1.1Fe11Ti to 1.5 MGOe in Ce1.05Fe9.75Co1.25Ti. Microscopy analysis indicates that the addition of Co refines the grain size and promotes chemical homogeneity at the microscopic scale. The beneficial effect of Co on the microstructure contributes to the improved hard magnetic properties.
High sensitivity microwave detection using a magnetic tunnel junction in the absence of an external applied magnetic field
Authors: Gui Y. S. , Xiao Y. , Bai L. H. , Hemour S. , Zhao Y. P. , Houssameddine D. , Wu K. , Guo H. , Hu C.-M.
Published: April 2015

In the absence of any external applied magnetic field, we have found that a magnetic tunnel junction (MTJ) can produce a significant output direct voltage under microwave radiation at frequencies, which are far from the ferromagnetic resonance condition, and this voltage signal can be increase by at least an order of magnitude by applying a direct current bias. The enhancement of the microwave detection can be explained by the nonlinear resistance/conductance of the MTJs. Our estimation suggests that optimized MTJs should achieve sensitivities for non-resonant broadband microwave detection of about 5000 mV/mW.
Energy-filtering-induced high power factor in PbS-nanoparticles-embedded TiS2
Authors: Wang Yulong , Wen Junfu , Fan Zhenghua , Bao Ningzhong , Huang Rong , Tu Rong , Wang Yifeng
Published: April 2015

We report on a greatly enhanced power factor for 1%PbS-nanoparticle-embedded TiS2 bulk ceramic, about 1 mW/(mK2) at 300 K and 1.23 mW/(mK2) in a wide temperature range of 573 ∼ 673 K, of which the latter is among the highest so far for TiS2-based thermoelectric materials. Compared to TiS2, the power factor is increased by ∼110% at 300 K and (50 ∼ 35)% at 573 ∼ 673 K. This enhancement is derived from a large increase in Seebeck coefficient which overwhelmed the modest degradation of electrical conductivity, which should be attributed to energy filtering induced by the band gap offset between TiS2 and PbS.
The role of atomic vacancies on phonon confinement in α-GeTe
Authors: Kalra Geetanjali , Murugavel Sevi
Published: April 2015

Atomic defects and their dynamics play a vital role in controlling the behavior of non-volatile phase change memory materials used in advanced optical storage devices. Synthesis and structural analysis by XRD and Raman spectroscopy on α-GeTe single crystal with different sizes are reported. The spectroscopic measurements on micron and nano sized α-GeTe single crystal reveal the evolution of phonon confinement with crystal sizes of few hundred nanometers. The characteristic vibrational modes of bulk α-GeTe structure are found to downshift and asymmetrically broaden to lower frequency with decreasing the single crystal size. We attribute the observed downshift of Raman lines in α-GeTe is largely due to the presence of high concentration of atomic vacancies. The crystal size and temperature dependent Raman spectra provide explicitly the dynamics of vacancies on optical phonon confinement in α-GeTe structure. Thus, the observed large concentration of vacancies and their size dependency might influence the phase change phenomenon in GeTe based alloys.
High-power microwave amplifier based on overcritical relativistic electron beam without external magnetic field
Authors: Kurkin S. A. , Frolov N. S. , Rak A. O. , Koronovskii A. A. , Kuraev A. A. , Hramov A. E.
Published: April 2015

The high-power scheme for the amplification of powerful microwave signals based on the overcritical electron beam with a virtual cathode (virtual cathode amplifier) has been proposed and investigated numerically. General output characteristics of the virtual cathode amplifier including the dependencies of the power gain on the input signal frequency and amplitude have been obtained and analyzed. The possibility of the geometrical working frequency tuning over the range about 8%–10% has been shown. The obtained results demonstrate that the proposed virtual cathode amplifier scheme may be considered as the perspective high-power microwave amplifier with gain up to 18 dB, and with the following important advantages: the absence of external magnetic field, the simplicity of construction, the possibility of geometrical frequency tuning, and the amplification of relatively powerful microwave signals.
Modulated optical sensitivity with nanostructured gallium nitride
Authors: Wilkins S. J. , Slomski M. J. , Paskova T. , Weyher J. L. , Ivanisevic A.
Published: April 2015

Surface functionalization via etching of high aspect ratio gallium nitride (GaN) nanostructures provides a way to modulate the optical properties in addition to properties gained from unique topographical formations. In this study, planar layered (heteroepitaxy) and bulk free-standing gallium nitride were modified via a phosphonic acid (1H,1H,2H,2H-perfluorooctanephosphonic acid) assisted phosphoric acid etch in conjunction with an aqueous KOH + K2S2O8 formed gallium nitride nanostructured surface. Despite the high defect concentrations in the thin planar and nanostructured GaN layer, the nanostructured GaN sample produced improved photoluminescence intensities versus the high quality bulk free-standing gallium nitride. Subsequent treatments with additive and additive-free phosphoric etches provided a means of additional optical manipulation in the form of red-shifting the near-band-edge (NBE) emission of the nanostructured GaN sample and increasing the maximum NBE photoluminescence intensity.
High throughput on-chip analysis of high-energy charged particle tracks using lensfree imaging
Authors: Luo Wei , Shabbir Faizan , Gong Chao , Gulec Cagatay , Pigeon Jeremy , Shaw Jessica , Greenbaum Alon , Tochitsky Sergei , Joshi Chandrashekhar , Ozcan Aydogan
Published: April 2015

We demonstrate a high-throughput charged particle analysis platform, which is based on lensfree on-chip microscopy for rapid ion track analysis using allyl diglycol carbonate, i.e., CR-39 plastic polymer as the sensing medium. By adopting a wide-area opto-electronic image sensor together with a source-shifting based pixel super-resolution technique, a large CR-39 sample volume (i.e., 4 cm × 4 cm × 0.1 cm) can be imaged in less than 1 min using a compact lensfree on-chip microscope, which detects partially coherent in-line holograms of the ion tracks recorded within the CR-39 detector. After the image capture, using highly parallelized reconstruction and ion track analysis algorithms running on graphics processing units, we reconstruct and analyze the entire volume of a CR-39 detector within ∼1.5 min. This significant reduction in the entire imaging and ion track analysis time not only increases our throughput but also allows us to perform time-resolved analysis of the etching process to monitor and optimize the growth of ion tracks during etching. This computational lensfree imaging platform can provide a much higher throughput and more cost-effective alternative to traditional lens-based scanning optical microscopes for ion track analysis using CR-39 and other passive high energy particle detectors.
Embodied Perception: A Proposal to Reconcile Affordance and Spatial Perception
Authors: Cañal-Bruland Rouwen , van der Kamp John
Published: April 2015

Proffitt's embodied approach to perception is deeply indebted to Gibson's ecological approach to visual perception, in particular the idea that the primary objects of perception are affordances or what the environment offers for action. Yet, rather than directly addressing affordance perception, most of the empirical work evaluating Proffitt's approach focuses on the perception of spatial properties of the environment. We propose that theoretical and empirical efforts should be directed toward an understanding of the relationship between affordance perception and spatial perception, keeping in mind that this relationship is nontrivial because affordance perception is dichotomous, whereas the perception of spatial properties is gradual. We argue that the perception of spatial properties of the environment is enslaved by affordance perception, most notably at the critical boundaries for action. To empirically scrutinize this proposition, and to solve issues raised regarding the validity of several empirical findings, we call for joint research efforts to further understanding of embodied perception.
Temperature responses of photosynthesis and respiration in a sub-Antarctic megaherb from Heard Island
Authors: Schortemeyer Marcus , Evans John R. , Bruhn Dan , Bergstrom Dana M. , Ball Marilyn C.
Published: April 2015

Understanding the response of sub-Antarctic plants to a warming climate requires an understanding of the relationship of carbon gain and loss to temperature. In a field study on Heard Island, we investigated the responses of photosynthesis and respiration of the sub-Antarctic megaherb Pringlea antiscorbutica R. Br. to temperature. This was done by instantaneously manipulating leaf temperature in a gas exchange cuvette on plants adapted to natural temperature variation along an altitudinal gradient. There was little altitudinal variation in the temperature response of photosynthesis. Photosynthesis was much less responsive to temperature than electron transport, suggesting that Rubisco activity was generally the rate-limiting process. The temperature response of leaf respiration rates was greater in cold-grown (high altitude) plants compared with warm-grown (low altitude) plants. This thermal acclimation would enable plants to maintain a positive carbon budget over a greater temperature range.
Metabolic theory and taxonomic identity predict nutrient recycling in a diverse food web
Authors: Allgeier Jacob Edward , Wenger Seth J. , Rosemond Amy D. , Schindler Daniel E. , Layman Craig A.
Published: April 2015

Significance

A fundamental dilemma in ecology is to reconcile the degree to which ecological processes are generalizable among taxa and ecosystems or determined primarily by taxonomic identity. We apply a unique dataset of organisms from a diverse marine community to test the applicability of two theories, metabolic theory of ecology (MTE) and ecological stoichiometry (EST), and the role of taxonomic identity for predicting nutrient excretion rates by fishes and macroinvertebrates. Excretion rates were principally explained by body mass and taxonomic identity, providing strong support for MTE, but also highlighting the intrinsic importance of taxonomic identity. Little support for basic predictions of EST was found. This research reveals animal-mediated nutrient cycling is largely generalizable by metabolic processes, but refined predictions require taxa-specific understanding.
The nucleotide exchange factors Grp170 and Sil1 induce cholera toxin release from BiP to enable retrotranslocation
Authors: Williams Jeffrey M. , Inoue Takamasa , Chen Grace , Tsai Billy
Published: April 2015

Cholera toxin (CT) intoxicates cells by trafficking from the cell surface to the endoplasmic reticulum (ER), where the catalytic CTA1 subunit hijacks components of the ER-associated degradation (ERAD) machinery to retrotranslocate to the cytosol and induce toxicity. In the ER, CT targets to the ERAD machinery composed of the E3 ubiquitin ligase Hrd1-Sel1L complex, in part via the activity of the Sel1L-binding partner ERdj5. This J protein stimulates BiP's ATPase activity, allowing BiP to capture the toxin. Presumably, toxin release from BiP must occur before retrotranslocation. Here, using loss-and gain-of-function approaches coupled with binding studies, we demonstrate that the ER-resident nucleotide exchange factors (NEFs) Grp170 and Sil1 induce CT release from BiP in order to promote toxin retrotranslocation. In addition, we find that after NEF-dependent release from BiP, the toxin is transferred to protein disulfide isomerase; this ER redox chaperone is known to unfold CTA1, which allows the toxin to cross the Hrd1-Sel1L complex. Our data thus identify two NEFs that trigger toxin release from BiP to enable successful retrotranslocation and clarify the fate of the toxin after it disengages from BiP.
On guided versus deflected fields in controlled-source electromagnetics
Authors: Swidinsky Andrei
Published: April 2015

The detection of electrically resistive targets in applied geophysics is of interest to the hydrocarbon, mining and geotechnical industries. Elongated thin resistive bodies have been extensively studied in the context of offshore hydrocarbon exploration. Such targets guide electromagnetic fields in a process which superficially resembles seismic refraction. On the other hand, compact resistive bodies deflect current in a process which has more similarities to diffraction and scattering. The response of a real geological structure is a non-trivial combination of these elements—guiding along the target and deflection around its edges. In this note the electromagnetic responses of two end-member models are compared: a resistive layer, which guides the electromagnetic signal, and a resistive cylinder, which deflects the fields. Results show that the response of a finite resistive target tends to saturate at a much lower resistivity than a resistive layer, under identical survey configurations. Furthermore, while the guided electromagnetic fields generated by a buried resistive layer contain both anomalous horizontal and vertical components, the process of electromagnetic deflection from a buried resistive cylinder creates mainly anomalous vertical fields. Finally, the transmitter orientation with respect to the position of a finite body is an important survey parameter: when the distance to the target is much less than the host skin depth, a transmitter pointing towards the resistive cylinder will produce a stronger signal than a transmitter oriented azimuthally with respect to the cylinder surface. The opposite situation is observed when the distance to the target is greater than the host skin depth.
Lipid Quality in Infant Nutrition
Authors: Delplanque Bernadette , Gibson Robert , Koletzko Berthold , Lapillonne Alexandre , Strandvik Birgitta
Published: April 2015

Dietary lipids are key for infants to not only meet their high energy needs but also fulfill numerous metabolic and physiological functions critical to their growth, development, and health. The lipid composition of breast milk varies during lactation and according to the mother's diet, whereas the lipid composition of infant formulae varies according to the blend of different fat sources. This report compares the compositions of lipids in breast milk and infant formulae, and highlights the roles of dietary lipids in term and preterm infants and their potential biological and health effects. The major differences between breast milk and formulae lie in a variety of saturated fatty acids (such as palmitic acid, including its structural position) and unsaturated fatty acids (including arachidonic acid and docosahexaenoic acid), cholesterol, and complex lipids. The functional outcomes of these differences during infancy and for later child and adult life are still largely unknown, and some of them are discussed, but there is consensus that opportunities exist for improvements in the qualitative lipid supply to infants through the mother's diet or infant formulae. Furthermore, research is required in several areas, including the needs of term and preterm infants for long‐chain polyunsaturated fatty acids, the sites of action and clinical effects of lipid mediators on immunity and inflammation, the role of lipids on metabolic, neurological, and immunological outcomes, and the mechanisms by which lipids act on short‐ and long‐term health.
Modelling non-symmetric collagen fibre dispersion in arterial walls
Authors: Holzapfel Gerhard A. , Niestrawska Justyna A. , Ogden Ray W. , Reinisch Andreas J. , Schriefl Andreas J.
Published: April 2015

New experimental results on collagen fibre dispersion in human arterial layers have shown that the dispersion in the tangential plane is more significant than that out of plane. A rotationally symmetric dispersion model is not able to capture this distinction. For this reason, we introduce a new non-symmetric dispersion model, based on the bivariate von Mises distribution, which is used to construct a new structure tensor. The latter is incorporated in a strain-energy function that accommodates both the mechanical and structural features of the material, extending our rotationally symmetric dispersion model (Gasser
et al.
2006
J. R. Soc. Interface
3
, 15–35. (
doi:10.1098/rsif.2005.0073
)). We provide specific ranges for the dispersion parameters and show how previous models can be deduced as special cases. We also provide explicit expressions for the stress and elasticity tensors in the Lagrangian description that are needed for a finite-element implementation. Material and structural parameters were obtained by fitting predictions of the model to experimental data obtained from human abdominal aortic adventitia. In a finite-element example, we analyse the influence of the fibre dispersion on the homogeneous biaxial mechanical response of aortic strips, and in a final example the non-homogeneous stress distribution is obtained for circumferential and axial strips under fixed extension. It has recently become apparent that this more general model is needed for describing the mechanical behaviour of a variety of fibrous tissues.
New evidence on the tool-assisted hunting exhibited by chimpanzees (Pan troglodytes verus) in a savannah habitat at Fongoli, Sénégal
Authors: Pruetz J. D. , Bertolani P. , Ontl K. Boyer , Lindshield S. , Shelley M. , Wessling E. G.
Published: April 2015

For anthropologists, meat eating by primates like chimpanzees (Pan troglodytes) warrants examination given the emphasis on hunting in human evolutionary history. As referential models, apes provide insight into the evolution of hominin hunting, given their phylogenetic relatedness and challenges reconstructing extinct hominin behaviour from palaeoanthropological evidence. Among chimpanzees, adult males are usually the main hunters, capturing vertebrate prey by hand. Savannah chimpanzees (P. t. verus) at Fongoli, Sénégal are the only known non-human population that systematically hunts vertebrate prey with tools, making them an important source for hypotheses of early hominin behaviour based on analogy. Here, we test the hypothesis that sex and age patterns in tool-assisted hunting (n=308 cases) at Fongoli occur and differ from chimpanzees elsewhere, and we compare tool-assisted hunting to the overall hunting pattern. Males accounted for 70% of all captures but hunted with tools less than expected based on their representation on hunting days. Females accounted for most tool-assisted hunting. We propose that social tolerance at Fongoli, along with the tool-assisted hunting method, permits individuals other than adult males to capture and retain control of prey, which is uncommon for chimpanzees. We assert that tool-assisted hunting could have similarly been important for early hominins.
The uptake and excretion of partially oxidized sulfur expands the repertoire of energy resources metabolized by hydrothermal vent symbioses
Authors: Beinart R. A. , Gartman A. , Sanders J. G. , Luther G. W. , Girguis P. R.
Published: April 2015

Symbiotic associations between animals and chemoautotrophic bacteria crowd around hydrothermal vents. In these associations, symbiotic bacteria use chemical reductants from venting fluid for the energy to support autotrophy, providing primary nutrition for the host. At vents along the Eastern Lau Spreading Center, the partially oxidized sulfur compounds (POSCs) thiosulfate and polysulfide have been detected in and around animal communities but away from venting fluid. The use of POSCs for autotrophy, as an alternative to the chemical substrates in venting fluid, could mitigate competition in these communities. To determine whether ESLC symbioses could use thiosulfate to support carbon fixation or produce POSCs during sulfide oxidation, we used high-pressure, flow-through incubations to assess the productivity of three symbiotic mollusc genera—the snailsAlviniconchaspp. andIfremeria nautilei, and the musselBathymodiolus brevior—when oxidizing sulfide and thiosulfate. Via the incorporation of isotopically labelled inorganic carbon, we found that the symbionts of all three genera supported autotrophy while oxidizing both sulfide and thiosulfate, though at different rates. Additionally, by concurrently measuring their effect on sulfur compounds in the aquaria with voltammetric microelectrodes, we showed that these symbioses excreted POSCs under highly sulfidic conditions, illustrating that these symbioses could represent a source for POSCs in their habitat. Furthermore, we revealed spatial disparity in the rates of carbon fixation among the animals in our incubations, which might have implications for the variability of productivityin situ. Together, these results re-shape our thinking about sulfur cycling and productivity by vent symbioses, demonstrating that thiosulfate may be an ecologically important energy source for vent symbioses and that they also likely impact the local geochemical regime through the excretion of POSCs.
Chryseobacterium solani sp. nov., isolated from field-grown eggplant rhizosphere soil
Authors: Du Juan , Ngo Hien T. T. , Won KyungHwa , Kim Ki-Young , Jin Feng-Xie , Yi Tae-Hoo
Published: April 2015

Strain THG-EP9T, a Gram-stain-negative, aerobic, motile, rod-shaped bacterium was isolated from field-grown eggplant (Solanum melongena) rhizosphere soil collected in Pyeongtaek, Gyeonggi–do, Republic of Korea. Based on 16S rRNA gene sequence comparisons, strain THG-EP9Thad closest similarity withChryseobacterium ginsenosidimutansTHG 15T(97.3  % 16S rRNA gene sequence similarity),Chryseobacterium soldanellicolaPSD1-4T(97.2 %),Chryseobacterium zeaeJM-1085T(97.2 %) andChryseobacterium indoltheticumLMG 4025T(96.8 %). DNA–DNA hybridization showed 5.7 % and 9.1 % DNA reassociation withChryseobacterium ginsenosidimutansKACC 14527TandChryseobacterium soldanellicolaKCTC 12382T, respectively. Chemotaxonomic data revealed that strain THG-EP9Tpossesses menaquinone–6 as the only respiratory quinone and iso-C15 : 0(29.0 %), C16 : 0(12.5 %) and iso-C17 : 03-OH (11.9 %) as the major fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, an unidentified aminophospholipid, two unidentified glycolipids, six unidentified aminolipids and two unidentified polar lipids. The DNA G+C content was 35.3 mol%. These data corroborated the affiliation of strain THG–EP9Tto the genusChryseobacterium. Thus, the isolate represents a novel species of this genus, for which the nameChryseobacterium solanisp. nov. is proposed, with THG-EP9T( = KACC 17652T = JCM 19456T) as the type strain.
Natural selection defines the cellular complexity
Authors: Chen Han , He Xionglei
Published: April 2015

Current biology is perplexed by the lack of a theoretical framework for understanding the organization principles of the molecular system within a cell. Here we first studied growth rate, one of the seemingly most complex cellular traits, using functional data of yeast single-gene deletion mutants. We observed nearly one thousandexpressioninformativegenes (EIGs) whose expression levels are linearly correlated to the trait within an unprecedentedly large functional space. A simple model considering six EIG-formed protein modules revealed a variety of novel mechanistic insights, and also explained ∼50% of the variance of cell growth rates measured by Bar-seq technique for over 400 yeast mutants (Pearson’sR= 0.69), a performance comparable to the microarray-based (R= 0.77) or colony-size-based (R= 0.66) experimental approach. We then applied the same strategy to 501 morphological traits of the yeast and achieved successes in most fitness-coupled traits each with hundreds of trait-specific EIGs. Surprisingly, there is no any EIG found for most fitness-uncoupled traits, indicating that they are controlled by super-complex epistases that allow no simple expression-trait correlation. Thus, EIGs are recruited exclusively by natural selection, which builds a rather simple functional architecture for fitness-coupled traits, and the endless complexity of a cell lies primarily in its fitness-uncoupled features.
Capturing heterotachy through multi-gamma site models
Authors: Bouckaert Remco , Lockhart Peter
Published: April 2015

Most methods for performing a phylogenetic analysis based on sequence alignments of gene data assume that the mechanism of evolution is constant through time. It is recognised that some sites do evolve somewhat faster than others, and this can be captured using a (gamma) rate heterogeneity model. Further, some species have shorter replication times than others, and this results in faster rates of substitution in some lineages. This feature of lineage specific rate variation can be captured to some extent, by using relaxed clock models. However, it is also clear that there are additional poorly characterised features of sequence data that can sometimes lead to extreme differences in lineage specific rates. This variation is poorly captured by constant time reversible substitution models. The significance of extreme lineage specific rate differences is that they lead both to errors in reconstructing evolutionary relationships as well as biased estimates for the age of ancestral nodes. We propose a new model that allows gamma rate heterogeneity to change on branches, thus offering a more realistic model of sequence evolution. It adds negligible computational cost to likelihood calculations. We illustrate its effectiveness with an example of green algae and land-plants. For many real world data sets, we find a much better fit with multi-gamma sites models as well as substantial differences in ancestral node date estimates.
Intrahippocampal glutamine administration inhibits mTORC1 signaling and impairs long-term memory
Authors: Rozas Natalia S. , Redell John B. , Pita-Almenar Juan D. , Mckenna James , Moore Anthony N. , Gambello Michael J. , Dash Pramod K.
Published: April 2015

The mechanistic Target of Rapamycin Complex 1 (mTORC1), a key regulator of protein synthesis and cellular growth, is also required for long-term memory formation. Stimulation of mTORC1 signaling is known to be dependent on the availability of energy and growth factors, as well as the presence of amino acids. In vitro studies using serum- and amino acid-starved cells have reported that glutamine addition can either stimulate or repress mTORC1 activity, depending on the particular experimental system that was used. However, these experiments do not directly address the effect of glutamine on mTORC1 activity under physiological conditions in nondeprived cells in vivo. We present experimental results indicating that intrahippocampal administration of glutamine to rats reduces mTORC1 activity. Moreover, post-training administration of glutamine impairs long-term spatial memory formation, while coadministration of glutamine with leucine had no influence on memory. Intracellular recordings in hippocampal slices showed that glutamine did not alter either excitatory or inhibitory synaptic activity, suggesting that the observed memory impairments may not result from conversion of glutamine to either glutamate or GABA. Taken together, these findings indicate that glutamine can decrease mTORC1 activity in the brain and may have implications for treatments of neurological diseases associated with high mTORC1 signaling.
National cultural values, sustainability beliefs, and organizational initiatives
Authors: Tata Jasmine , Prasad Sameer
Published: April 2015

Purpose

– Organizations are implementing sustainability initiatives in different countries with varied socio-cultural systems. The literature on sustainability, however, does not present a clear picture of how national culture can influence interpretations of the meaning of sustainability and how these differences in interpretation can result in different sustainability practices. The purpose of this paper is to build upon the current literature by identifying mechanisms (i.e. sustainability beliefs and perceptions) that mediate the relationship between national cultural values and organizational sustainability initiatives.

Design/methodology/approach

– The authors examine the literature on culture and sustainability practices, and develop a conceptual model that identifies how cultural values influence the sustainability initiatives of organizations. Several propositions are identified that specify relationships among the constructs, and guidelines are provided for testing the model in future research.

Findings

– The model posits that national culture influences sustainability beliefs and perceptions, which in turn influence the quantity and scope of sustainability initiatives. The relationship between sustainability beliefs and organizational sustainability initiatives is moderated by sustainability orientation and organizational capacity.

Originality/value

– The model can help researchers and practitioners better understand the meaning of sustainability in the context of international business by identifying the mechanisms that explain the link between culture and sustainability. It can also help researchers generate hypotheses for future research. Finally, the model can guide multinational corporations attempting to drive sustainability programs through their subsidiaries as well as international developmental agencies trying to develop programs in partnership with local non-governmental organizations (NGOs).
Do different national samples yield similar dimensions of national culture?
Authors: Minkov Michael , Bond Michael Harris , Blagoev Vesselin
Published: April 2015

Purpose

– Cross-national studies of employees’ values and beliefs have extracted dimensions of national culture from diverse samples of employees. The purpose of this paper is to find out if this sample diversity impacts the nature of the extracted dimensions: is a given dimension replicable across diverse samples (such as managers vs skilled workers?).

Design/methodology/approach

– The authors analyzed a set of values from the World Values Survey, comparing nation-level value structures from four types of samples in 46 countries: national representation, managers, experts without supervisory duties, and skilled workers. The authors analyzed the data with, and simultaneously compared, two data reduction methods: multidimensional scaling (MDS) plots (Shalom Schwartz’s preferred method) vs exploratory factor analysis (EFA).

Findings

– MDS plots suggested structural similarity across the four samples, whereas EFA suggests divergence.

Research limitations/implications

– Whether dimensions of national culture replicate across different samples or not depends on the data reduction method. There is no one best method in an abstract sense. Researchers’ choice of method should be contingent on their research philosophy: theory-driven vs empirical.

Originality/value

– No such study has been published previously.
PUKAR: an “Alice” in Wonderland
Authors: Tiwari Shalini Rahul , Chopra Rakesh
Published: April 2015

Subject area

Social Entrepreneurship/management of non-profit organizations (and non-government organizations).

Study level/applicability

Undergraduate/MBA/Executive MBA.

Case overview

PUKAR is a niche non-government organization (NGO) working on a unique concept of “Right to Research”. It has several themes aimed at democratizing research and broadening access to knowledge among the disenfranchised or the weakly institutionalized groups. The resulting output is disseminated through media such as lectures, Web site, books and newsletters, thus initiating local, national and global debates about future of these groups. PUKAR conceptualizes all projects around this philosophy, which are supported by few specialized funding organizations. Funding organizations, on the other hand, are trying to support many causes aimed at improving the quality of life of citizens of various countries. Thus, PUKAR's growth is constrained by limited funds. Nevertheless, PUKAR has been able to create transformation in the lives of youth who carry out these projects. PUKAR, therefore, faces a continuous challenge of conceptualizing proposals that are meaningful and impactful for the society and to stay true to its core philosophy.

Expected learning outcomes

The expected learning outcomes include: to understand the nature of challenges (both strategic and operational) faced by a niche NGO; to analyze how the strategy of an NGO evolves with time; to analyze the impediments of growth for a niche NGO; and to analyze the strategic options for growth and sustenance of an NGO.

Supplementary materials

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Sharī‘ah court-annexed dispute resolution of three commonwealth countries – a literature review
Authors: Oseni Umar Aimhanosi
Published: April 2015

Purpose

– The purpose of this study is to examine the legal framework for court-annexed dispute resolution in courts with Sharī‘ah jurisdiction in Nigeria, Malaysia and Singapore. The major part of the study is dedicated to propose reforms in the administration of justice system in the courts with Sharī‘ah jurisdiction in Nigeria and the relevance of such reforms to the ongoing reforms in the Middle East and North African (MENA) countries.

Design/methodology/approach

– This is an integrative literature review, which adopts a comparative approach in analyzing the conceptual framework of amicable dispute resolution in the modern world with particular reference to the Sharī‘ah court.

Findings

– The findings of this research illustrate the adaptability of the practices in Malaysia and Singapore in the courts with Sharī‘ah jurisdiction in Nigeria and the MENA region.

Practical implications

– An exposition of the dispute resolution processes in Islamic law reveals the relevance of these processes in modern reforms of the administration of justice system. The practical implications of this study include the streamlining of the rules and procedures of modern Sharī‘ah courts in post-revolution Arab countries to allow for court-annexed amicable (alternative) dispute resolution initiatives.

Originality/value

– As far as it is known, this is the first conceptual study on the court-annexed dispute resolution frameworks of Sharī‘ah courts in three commonwealth jurisdictions.
The relationship between labour social responsibility practices and reputation
Authors: Odriozola María Dolores , Martín Antonio , Luna Ladislao
Published: April 2015

Purpose

– The purpose of this paper is to analyse whether labour social responsibility (LSR) practices influence on corporate reputation (CR) and on labour reputation (LR).

Design/methodology/approach

– LSR is defined as all those labour practices made by a company for the benefit of employees voluntarily and not imposed by labour legislation. An index developed by content analysis was created to measure LRS. CR and LR scores were obtained from the Business Monitor of Corporate Reputation (MERCO) for the period of 2006-2010. Furthermore, based on the previous literature, the study considers other generic variables that influence the process of creating reputation, such as visibility and environmental impact, as well as intrinsic characteristics of each company (size, financial performance and debt). The model was estimated by the generalised method of moments (GMM) on a data panel for the 100 most reputable firms in Spain in each year during the period 2006-2010.

Findings

– The results obtained show that LSR carried out by the company has a direct and positive relationship with the reputation. Thus, corporate and labour reputation and their evolution depend on ability of the LSR strategy of the company to satisfy to future expectations of stakeholders.

Originality/value

– Previous literature considered the impact of different dimensions of corporate social responsibility on CR, e.g., environmental, communication, quality of products, but did not consider labour practices.
The effect of sexual activity on wages
Authors: Drydakis Nick
Published: April 2015

Purpose

– The purpose of this paper is to estimate whether sexual activity is associated with wages, and also to estimate potential interactions between individuals’ characteristics, wages and sexual activity.

Design/methodology/approach

– The central hypothesis behind this research is that sexual activity, alike health indicators and mental well-being, may be thought of as part of an individual’s set of productive traits that affect wages. Using two-stage estimations the author examines the relationship between adult sexual activity and wages.

Findings

– The author estimates that there is a monotonic relationship between the frequency of sexual activity and wage returns, whilst the returns to sexual activity are higher for those between 26 and 50 years of age. In addition, heterosexuals’ sexual activity does not seem to provide higher or lower wage returns than that of homosexuals, but wages are higher for those health-impaired employees who are sexually active. Over-identification tests, robustness checks, falsification tests, as well as, decomposition analysis and sample selection modelling enhance study’s strength.

Social implications

– Contemporary social analysis suggests that health, cognitive and non-cognitive skills and personality are important factors that affect wage level. Sexual activity may also be of interest to social scientists, since sexual activity is considered to be a barometer for health, quality of life, well-being and happiness.

Originality/value

– The paper adds to the literature on the importance of unobserved characteristics in determining labour market outcomes.
Discriminating debris particle in lubricant by ultrasonic waveshape features
Authors: Xu Chao , Zhang Peilin , Ren Guoquan , Li Bing , Wu Dinghai , Fan Hongbo
Published: April 2015

Purpose

– This paper aims to provide an effective method so that the ultrasonic technique can be applied to the online debris particle detection. It proposes utilizing the waveshape features in discriminating the debris particle in lubricant.

Design/methodology/approach

– The finite element model has been developed to investigate the scattering of the ultrasonic waves in lubricant containing single scatterer, such as the debris particle and the air bubble. The simulation results show that the results verify that different scatterers differ in the waveshape features. The static experiments were carried out on a specially fixture. The single spherical debris, long debris and air bubble were measured. The fast Fourier transform (FFT) method was applied to the analysis of the echo signals to obtain the features implicated in the waveshape.

Findings

– The research of this paper verifies that different scatterers differ both in their shape features and in the FFT analysis features.

Research limitations/implications

– The rapid movement of the debris particles as well as the lubricant temperature may influence the measuring signals. Besides, the measuring signals are usually corrupted by noise, especially for the tiny debris. Therefore, researchers are encouraged to solve those problems further.

Practical implications

– The paper includes implications for the improvement in the online debris detection and the development of the ultrasonic technique applied in online debris detection.

Originality/value

– The paper provides a promising way that the ultrasonic waveshape features can be utilized to the identify debris particle online.
Tribological and corrosive properties of ionic liquids containing triazole functional groups
Authors: Li Jinlong , Li Dongmei , Zhou Feng , Feng Dapeng , Xia Yanqiu , Liu Weimin
Published: April 2015

Purpose

– The aim of this paper was to inhibit the serious corrosion of conventional ionic liquids, a series of new ionic liquids (ILs) containing the triazole functionality, as the anti-corrosion groups were synthesized in this work.

Design/methodology/approach

– It is well known that nitrogen and sulfur containing organic compounds have been traditionally used as corrosion inhibitors. Among them, triazole derivatives are most often used as corrosion inhibitors. To alleviate the corrosion of the ILs and further improve the anti-wear property, the authors prepared a series of imidazolium ILs modified with the triazole functionality in the present study.

Findings

– The corrosion behavior of the ILs was evaluated with the iron disk corrosion test and their tribological properties were investigated on an Optimol SRV IV oscillating friction and wear tester at elevated temperatures. The results showed that the ILs with the triazole functionality could effectively reduce the corrosion and exhibit a smaller friction coefficient and wear volume than the unmodified counterpart. The ILs containing the triazole functionality can be used as the single component anti-corrosion base oils even at elevated temperatures.

Originality/value

– The results showed that the ILs with the triazole functionality could effectively reduce the corrosion and exhibit a smaller friction coefficient and wear volume than the unmodified counterpart. The ILs containing the triazole functionality can be used as the single component anti-corrosion base oils even at elevated temperatures.