bluuebunny/crossref_metadata_2025 huggingface dataset:
Observation of a Topological Edge State in the X‐ray Band
Authors: Huang Qiushi , Guo Zhiwei , Feng Jiangtao , Yu Changyang , Jiang Haitao , Zhang Zhong , Wang Zhanshan , Chen Hong
Published: May 2019

The possibility of obtaining edge states of light that are robust against disorder by mimicking the topological properties of a solid‐state system has brought a profound impact on optical sciences. In the short‐wavelength region, X‐ray science and technology is undergoing tremendous development. It requires high‐precision optics with exquisite control of light properties and robustness against structural perturbations. Therefore, it is very attractive to extend the concept of optical topological manipulation to the X‐ray regime. Herein, the topological edge state is theoretically proposed and experimentally demonstrated at the interface of two kinds of photonic crystals having different bandgap topological characteristics in the X‐ray regime. Remarkably, this topologically protected edge state is immune to the thickness disorder as long as the zero‐average‐effective‐mass condition is satisfied. This work extends the topological photonics to the X‐ray regime and paves the way for the development of novel X‐ray optics such as high‐resolution X‐ray filters/monochromators, or X‐ray quantum optics, to realize the phenomena such as Rabi splitting that are robust against disorders.
Preparation and pH‐Dependent Properties of Hydrogels Based on Acidic Copolymers with PEG Side Chains and α‐Cyclodextrin
Authors: Stößlein Sebastian , Grunwald Ingo , Khachikyan Alexander , Faßbender Fabian , Thiel Karsten , Hartwig Andreas
Published: May 2019

A variety of differently structured PEG‐based polymers can form physically cross‐linked PEG hydrogels with α‐cyclodextrin. The polymer structures strongly influence the properties of the hydrogel and its formation. Four different copolymers of methoxy PEG methacrylate and methacrylic acid are used together with α‐cyclodextrin to study hydrogel formation speed and gel strength. The hydrogels are formed within 1–25 min, and the formation process is examined in situ by dynamic light scattering. The gel formation time is pH dependent due to the methacrylic acid present in the polymers. The gel strength examined by texture analyzer also depends on the composition and pH. With prior mechanical destruction, all hydrogels are dissolvable in an excess of water, being a useful feature for an in vivo usage. By analyzing the structures of the hydrogels with confocal light microscopy (laser scanning confocal microscopy) and scanning electron microscope (SEM) after freeze etching, the different hydrogel structures can be observed.
Wolf–Lamb‐type Catalysis in One Pot Using Electrospun Polymeric Catalyst Membranes
Authors: Pretscher Martin O. , Gekle Stephan , Agarwal Seema
Published: May 2019

Multistep catalytic transformations using incompatible catalysts (Wolf–Lamb‐type) in a one‐pot reaction cascade require site isolation of different catalysts by compartmentalization. In this work, the use of different electrospun catalytic membranes in a modular way as individual compartments is shown for one‐pot Wolf–Lamb‐type reaction cascades. The data are presented for one‐pot cascade reaction sequences catalyzed by acidic and basic membranes made by electrospinning polymeric acid (poly(styrene‐co‐styrene sulfonic acid‐co‐4‐methacryloyl‐oxybenzophen)) and basic (poly(styrene‐co‐4‐vinylpyridine‐co‐4‐methacryloyl‐oxybenzophen)) catalysts, respectively. The two‐step, one‐pot system used is the acidic catalyzed deacetylation of dimethoxybenzylacetale to benzaldehyde, which reacts with ethyl cyanoformate to result in a high yield of product (over 90%) under base‐catalyzed conditions. The reaction kinetics are further monitored and evaluated by using differential equations, showing the necessity of a parameter Δt to represent a retarded start for the second reaction step. The concept provides an easy and upscalable approach for use in Wolf–Lamb‐type systems.
Study of the influence of the structural grain size on the mechanical properties of technical materials
Authors: Harničárová M. , Valíček J. , Kušnerová M. , Kmec J. , Palková Z. , Kopal I. , Krmela J. , Panda A.
Published: May 2019

The mechanical properties of technical materials depend on their structure. They are influenced not only by their chemical composition, but particularly by the structural grain size. Significant changes in the mechanical behaviour of materials are related both to surface and volume properties, and not only in the field of mechanical parameters. A wide range of physical and chemical parameters changes as well. Nano‐materials are the materials, the structural grain size of which is in the dimensional area from 10−9 to 10−7 m. Nano‐particles and nanostructures are thus so small that their behaviour is affected by atomic forces, properties of chemical bonding, and quantum phenomena. The wave nature of the very small particles begins to manifest itself. The aim of the authors is to contribute by their paper to the solution of the problems in the field of material engineering. This means to investigate the specifics in the behaviour of technical materials depending on the change in the structural grain size towards the nano‐areas, as well as the design and use of new techniques of mathematical and physical modelling including the operative measurement method.
Seismic analysis of inelastic cantilever column systems
Authors: Borodin L.A. , Strashnov S.V. , Rynkovskaya M.
Published: May 2019

Seismic analysis still has many issues to be investigated not only in countries which are situated in seismic regions but also in European countries, as it was seen in Italy, Greece and Turkey in 2017 [1]. Based on calculations, methods of theoretical and experimental research we performed synthesis reactions of the structural systems of the console type on the seismic effects. To identify structural architectonics of objects, a regular structure which includes geometrically non‐changeable (or slightly changeable) vertical spinal fragments and seismic safety bearing members with plastic hinges at the nodal connections is used. The determining factor of the stress‐strain state of the structural system is the angular displacement relative to the base in the form of deviations close to the rectilinear approximation. The method of seismic analysis of inelastic cantilever column systems of regular structure is developed [2]. The method is based on the energy principle for analysis of inelastic systems as a quasistatic problem. The results can be extended for ecological materials such as bamboo [3].
Numerical study of the interfaces of 3D‐printed concrete using discrete element method
Authors: Valle‐Pello P. , Álvarez‐Rabanal F.P. , Alonso‐Martínez M. , del Coz Díaz J.J.
Published: May 2019

3D concrete printing is an additive manufacturing method which reduces the time and improves the efficiency of the construction process. Structural behavior of printed elements is strongly influenced by the properties of the material and the interface surfaces. The printing process creates interface surfaces between layers in the horizontal and vertical directions. The bond strength between layers is the most critical property of printed elements. In this paper, the structural behavior of printed elements is studied using the discrete element method. The material is modelled using discrete particles with bonding between them. A new discrete model of a multilayer geometry is presented to study the behavior of the interfaces of printed concrete. The layers are made up of randomly placed particles to simulate the heterogeneous nature of concrete. The numerical model is developed to simulate the flexural behavior of multilayer specimens. A four‐point flexural test is simulated considering the interface surfaces between layers. This numerical model provides relevant results to improve the behavior of this kind of structural elements. The aim of this work is to provide a discrete element model to predict the mechanical behavior of 3D concrete printed components.
Fatigue crack propagation behavior in AISI 304 steel welded joints for cold‐stretched liquefied natural gas (LNG) storage tank at cryogenic temperatures
Authors: Heo I.K. , Yoon D.H. , Kim J.H. , Kim H.C. , Kim K.D.
Published: May 2019

AISI304 steel welded joints are used in cold‐stretched liquefied natural gas (LNG) storage tanks used for storing and transporting of liquefied gases. Compared with a conventional liquefied natural gas storage tank, a cold‐stretched liquefied natural gas storage tank has many advantages such as reduced thickness, light weight, low cost and low energy consumption. However, liquefied natural gas storage tanks can be subjected to alternative loads at cryogenic temperatures; thus, it is important to investigate the fatigue crack propagation behavior in AISI 304 steel welded joints at cryogenic temperatures. Specimens were machined from a cold‐stretched liquefied natural gas storage tank with a welding structure. The crack length was determined using compliance method and confirmed by examination with traveling microscope. Fatigue crack propagation rates were evaluated at various stress ratios and temperatures. The fatigue crack growth rate of all specimens a little appears the effect of stress ratio, but it has a great influence at a cryogenic temperature. The fatigue crack growth rate of longitudinal welded joint is the fastest at room and cryogenic temperature. Fracture mechanism in the specimen is examined using a scanning electron microscope.
Finite element modeling of nano porous sintered silver material using computed tomography images
Authors: Meyghani B. , Awang M. , Bokam P. , Plank B. , Heinzl C. , Siow K. S.
Published: May 2019

Limitations in the packaging industry require improvements in lead‐based microelectronics, because regulations restricting hazardous substances have ended the use of conventional lead‐based solders. Sintered silver paste presents an alternative method for bonding chips to a substrate because it has low sensitivity to the oxidation, high melting point, and improved thermal and electrical conductivity. Due to the sintering process, however, the silver exhibits a significant pore fraction that substantially reduces the density of the material compared to bulk silver. The traits of the sintered silver pastes are affected by the pore distribution; hence, it can be considered as a significant factor in modelling the behaviour of the whole electronic system under operating conditions. This study defines the influence of the morphology and pore distribution on the response of the silver material. The quality of tomographic images was improved through coding a program in MATLAB®. Finite element software ABAQUS® was employed to evaluate the elastic properties of the material. To validate the model, the results have gone through several studies to determine changes of the material properties.
Labyrinth seals with application to turbomachinery
Authors: Ilieva G. , Pirovsky C.
Published: May 2019

It is well known that there exist losses of fluid through axial and radial gaps in turbomachines, leading to less efficiency. Every 1 % decrease in leakage flow through a high‐pressure gas turbine seals would result in a 0.4 % decrease in the specific fuel consumption [1]. Last decades, a number of solutions have been applied to overcome losses of fluid through axial and radial gaps. A feasible solution is the application of labyrinth seals to act as an obstacle on the way of flow leakages. This research is targeted to attain a seal configuration that has good dynamic sealing properties, higher compliance with the shaft, simple geometry for manufacturing and maintenance. The labyrinth seal must produce significant losses of kinetic energy in order to stop leaks passing through the sealed places. It is known that the turbine shaft exhibits modal and stress loads. Also, seals must be designed to resist loads and operate at maximum efficiency. The fulfilled numerical analysis shows that the proposed geometry causes intensive reduction of leakage flow rates and thus contributes to increase in the efficiency performance of stages under consideration.
Numerical model for dynamic analysis of masonry‐infilled steel and concrete frames
Authors: Baloevic G. , Radnic J. , Grgic N.
Published: May 2019

A numerical model for nonlinear dynamic analysis of planar masonry‐infilled concrete and steel frames strengthened with composites is briefly presented. The model is quite simple and it can simulate main nonlinear effects of these structures. Besides modelling of nonlinear behavior of concrete, steel, masonry, plaster and soil, it can simulate nonlinearities at contact surfaces, changes in structural geometry and construction of a structure over different time phases. The model is based on a relatively small number of material parameters and intended for practical application primarily. The model is verified by using the data of the performed shake‐table tests on masonry‐infilled steel and concrete frames. Numerical results show fairly good agreement with the experimental results. This shows the potential reliability of the developed numerical model for the analysis of planar masonry structures. However, further verifications of the model and corresponding computational software are most welcome.
The small subunit of DNA polymerase D (DP1) associates with GINS–GAN complex of the thermophilic archaea in Thermococcus sp. 4557
Authors: Lu Shuhong , Zhang Xuesong , Chen Kaiying , Chen Zimeng , Li Yixiang , Qi Zhongquan , Shen Yulong , Li Zhuo
Published: May 2019

The eukaryotic GINS, Cdc45, and minichromosome maintenance proteins form an essential complex that moves with the DNA replication fork. The GINS protein complex has also been reported to associate with DNA polymerase. In archaea, the third domain of life, DNA polymerase D (PolD) is essential for DNA replication, and the genes encoding PolDs exist only in the genomes of archaea. The archaeal GAN (GINS‐associated nuclease) is believed to be a homolog of the eukaryotic Cdc45. In this study, we found that the Thermococcus sp. 4557 DP1 (small subunit of PolD) interacted with GINS15 in vitro, and the 3′–5′ exonuclease activity of DP1 was inhibited by GINS15. We also demonstrated that the GAN, GINS15, and DP1 proteins interact to form a complex adapting a GAN–GINS15–DP1 order. The results of this study imply that the complex constitutes a core of the DNA replisome in archaea.
Band‐selective excitation NMR spectroscopy and quantitative time‐domain analysis using Complete Reduction to Amplitude‐Frequency Table (CRAFT) to determine distribution coefficients during drug development
Authors: Soulsby David
Published: May 2019

A sensitive quantitative 1H NMR method for determining distribution or partition coefficients has been developed that is applicable to early drug discovery. After partitioning and equilibration, aliquots from each layer are analyzed using band‐selective excitation 1H NMR spectroscopy in regions that are free of 1‐octanol and water solvent signals. Signals are quantitated directly using CRAFT software, and their amplitudes are adjusted to correct for nonuniformity within the excitation band. Using this approach, the distribution coefficients for 20 drugs present at low concentrations were determined giving values that were in excellent agreement with literature values.
Accelerated whole‐brain perfusion imaging using a simultaneous multislice spin‐echo and gradient‐echo sequence with joint virtual coil reconstruction
Authors: Manhard Mary Kate , Bilgic Berkin , Liao Congyu , Han SoHyun , Witzel Thomas , Yen Yi‐Fen , Setsompop Kawin
Published: May 2019

Purpose

Dynamic susceptibility contrast imaging requires high temporal sampling, which poses limits on achievable spatial coverage and resolution. Additionally, more encoding‐intensive multi‐echo acquisitions for quantitative imaging are desired to mitigate contrast leakage effects, which further limits spatial encoding. We present an accelerated sequence that provides whole‐brain coverage at an improved spatio‐temporal resolution, to allow for dynamic quantitative R2 and R2* mapping during contrast‐enhanced imaging.

Methods

A multi‐echo spin and gradient‐echo sequence was implemented with simultaneous multislice acquisition. Complementary k‐space sampling between repetitions and joint virtual coil reconstruction were used along with a dynamic phase‐matching technique to achieve high‐quality reconstruction at 9‐fold acceleration, which enabled 2 × 2 × 5 mm whole‐brain imaging at TR of 1.5 to 1.7 seconds. The multi‐echo images from this sequence were fit to achieve quantitative R2 and R2* maps for each repetition, and subsequently used to find perfusion measures including cerebral blood flow and cerebral blood volume.

Results

Images reconstructed using joint virtual coil show improved image quality and g‐factor compared with conventional reconstruction methods, resulting in improved quantitative maps with a 9‐fold acceleration factor and whole‐brain coverage during the dynamic perfusion acquisition.

Conclusion

The method presented shows the advantage of using a joint virtual coil–GRAPPA reconstruction to allow for high acceleration factors while maintaining reliable image quality for quantitative perfusion mapping, with the potential to improve tumor diagnostics and monitoring.
Alteration in AMPA receptor subunit expression and receptor binding among patients with addictive disorders: A systematic review of human postmortem studies
Authors: Ueno Fumihiko , Suzuki Takefumi , Nakajima Shinichiro , Matsushita Sachio , Mimura Masaru , Miyazaki Tomoyuki , Takahashi Takuya , Uchida Hiroyuki
Published: May 2019

Background and Objectives

Altered trafficking of α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) receptors has been reported in postmortem studies and suggested the involvement of AMPA receptors in the pathophysiology underpinning addictive disorders. However, these findings seemed mixed.

Methods

A systematic literature search was conducted, using PubMed and Embase (last search, August 2018), to identify human postmortem studies that examined the expression of proteins and mRNA of AMPA receptor subunits in patients with addictive disorders in comparison with healthy controls.

Results

Twelve (18 studies) out of 954 articles were identified to be relevant. Eight studies included alcohol use disorders, and four studies included heroin/cocaine abusers. The most frequently investigated regions were the hippocampus (three studies), amygdala (three studies), and putamen (three studies). In summary, two out of the three studies showed an increase in the expression of AMPA receptors in the hippocampus, while the other study found no change. Two studies to examine the amygdala demonstrated either a decreased or no change in receptor expression or binding. Concerning putamen, two studies showed no significant change whereas an overexpression of receptors was observed in the other.

Conclusions and Scientific Significance

The hippocampus and amygdala may be pertinent to addictive disorders through their functions on learning and memory, whereas findings in other regions were inconsistent across the studies. Human postmortem studies are prone to degenerative changes after death. Moreover, only qualitative assessment was conducted because of the limited, heterogenous data. These limitations emphasize the need to investigate AMPA receptors in the living human brains.
Navigating within thiamine diphosphate‐dependent decarboxylases: Sequences, structures, functional positions, and binding sites
Authors: Buchholz Patrick C. F. , Ferrario Valerio , Pohl Martina , Gardossi Lucia , Pleiss Jürgen
Published: May 2019

Thiamine diphosphate‐dependent decarboxylases catalyze both cleavage and formation of CC bonds in various reactions, which have been assigned to different homologous sequence families. This work compares 53 ThDP‐dependent decarboxylases with known crystal structures. Both sequence and structural information were analyzed synergistically and data were analyzed for global and local properties by means of statistical approaches (principle component analysis and principal coordinate analysis) enabling complexity reduction. The different results obtained both locally and globally, that is, individual positions compared with the overall protein sequence or structure, revealed challenges in the assignment of separated homologous families. The methods applied herein support the comparison of enzyme families and the identification of functionally relevant positions. The findings for the family of ThDP‐dependent decarboxylases underline that global sequence identity alone is not sufficient to distinguish enzyme function. Instead, local sequence similarity, defined by comparisons of structurally equivalent positions, allows for a better navigation within several groups of homologous enzymes. The differentiation between homologous sequences is further enhanced by taking structural information into account, such as BioGPS analysis of the active site properties or pairwise structural superimpositions. The methods applied herein are expected to be transferrable to other enzyme families, to facilitate family assignments for homologous protein sequences.
Effect of natural predators on Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) control by sterile insect technique (SIT)
Authors: Rathnayake Darshana N , Lowe Elizabeth C , Rempoulakis Polychronis , Herberstein Marie E
Published: May 2019

BACKGROUND

Queensland fruit fly (Q‐fly) is a destructive insect pest that infests a wide variety of agricultural plants in Australia. The sterile insect technique (SIT) is used to manage Q‐flies, but the effectiveness of SIT has not been tested in the presence of natural predators. The objective of this study was to investigate the effect of natural predators and SIT on the survival and reproduction of laboratory reared Q‐flies under semi‐natural conditions. We altered the presence of predators and irradiated Q‐fly males, and measured survival, number of eggs laid and egg‐hatching rate.

RESULTS

The presence of natural predators significantly affected the survival of Q‐flies and appeared to decrease the number of eggs laid. Interestingly, we found that both sterile and fertile males were more prone to predation than females, but we found no difference among males. The presence of sterile males significantly reduced Q‐fly fertility, but the interaction of natural predators and sterile males did not significantly reduce the number of fertile eggs.

CONCLUSION

Our findings highlight the important role of natural predators in controlling Q‐flies together with SIT and provide a solid foundation for similar large‐scale field trials using wild counterparts. © 2019 Society of Chemical Industry
Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated review
Authors: Soleimani Vahid , Delghandi Parisa Sadat , Moallem Seyed Adel , Karimi Gholamreza
Published: May 2019

Milk thistle (Silybum marianum) is a medicinal plant from the Asteraceae family. Silymarin is the major constituent of milk thistle extract and is a mixture of some flavonolignans such as silybin, which is the most active component of silymarin. It is most commonly known for its hepatoprotective effect. Also, studies have shown other therapeutic effects such as anticancer, anti‐Alzheimer, anti‐Parkinson, and anti‐diabetic, so its safety is very important. It has no major toxicity in animals. Silymarin was mutagen in Salmonella typhimurium strains in the presence of metabolic enzymes. Silybin, silydianin, and silychristin were not cytotoxic and genotoxic at concentration of 100 μM. Silymarin is safe in humans at therapeutic doses and is well tolerated even at a high dose of 700 mg three times a day for 24 weeks. Some gastrointestinal discomforts occurred like nausea and diarrhea. One clinical trial showed silymarin is safe in pregnancy, and there were no anomalies. Consequently, caution should be exercised during pregnancy, and more studies are needed especially in humans. Silymarin has low‐drug interactions, and it does not have major effects on cytochromes P‐450. Some studies demonstrated that the use of silymarin must be with caution when co‐administered with narrow therapeutic window drugs.
A review on recent advances in soft surgical robots for endoscopic applications
Authors: Gifari M. Wildan , Naghibi Hamid , Stramigioli Stefano , Abayazid Momen
Published: May 2019

Background

Soft materials, with their compliant properties, enable conformity and safe interaction with human body. With the advance in actuation and sensing of soft materials, new paradigm in robotics called “soft robotics” emerges. Soft robotics has become a new approach in designing medical devices such as wearable robotic gloves and exoskeleton. However, application of soft robotics in surgical instrument inside human body is still in its infancy.

Aims

In this paper, current application and design of soft robots specifically applied for endoscopy are reviewed.

Materials & Methods

Different aspects in the implementation of soft robotics in endoscope design were reviewed. The key studies about MIS and NOTES were reviewed to establish the clinical background and extract the limitations of current endoscopic device in the last decade.

Results and discussion

In this review study, the implementation of soft robotics concepts in endoscopic application, with highlights on different features of several soft endoscopes, were evaluated. The progress in different aspects of soft robotics endoscope, current state, and future perspectives were also discussed.

Conclusion

Based on the survey on the structural specification, actuation, sensing, and stiffening the future soft surgical endoscopes are recommended to fulfil the following specifications: safe especially from pressure leakage, fully biocompatible materials, MR‐compatible, capable for large bending in at least two antagonistic directions, modularity, adjustable stiffness.
Improving Polysulfides Adsorption and Redox Kinetics by the Co4N Nanoparticle/N‐Doped Carbon Composites for Lithium‐Sulfur Batteries
Authors: Xiao Kuikui , Wang Jin , Chen Zhen , Qian Yuhong , Liu Zheng , Zhang Lili , Chen Xiaohua , Liu Jilei , Fan Xiaofeng , Shen Ze Xiang
Published: May 2019

Improved conductivity and suppressed dissolution of lithium polysulfides is highly desirable for high‐performance lithium‐sulfur (Li‐S) batteries. Herein, by a facile solvent method followed by nitridation with NH3, a 2D nitrogen‐doped carbon structure is designed with homogeneously embedded Co4N nanoparticles derived from metal organic framework (MOF), grown on the carbon cloth (MOF‐Co4N). Experimental results and theoretical simulations reveal that Co4N nanoparticles act as strong chemical adsorption hosts and catalysts that not only improve the cycling performance of Li‐S batteries via chemical bonding to trap polysulfides but also improve the rate performance through accelerating the conversion reactions by decreasing the polarization of the electrode. In addition, the high conductive nitrogen‐doped carbon matrix ensures fast charge transfer, while the 2D structure offers increased pathways to facilitate ion diffusion. Under the current density of 0.1C, 0.5C, and 3C, MOF‐Co4N delivers reversible specific capacities of 1425, 1049, and 729 mAh g−1, respectively, and retains 82.5% capacity after 400 cycles at 1C, as compared to the sample without Co4N (MOF‐C) values of 61.3% (200 cycles). The improved cell performance corroborates the validity of the multifunctional design of MOF‐Co4N, which is expected to be a potentially promising cathode host for Li‐S batteries.
Punching shear behavior of reinforced concrete flat slabs with a varying amount of shear reinforcement
Authors: Schmidt Philipp , Kueres Dominik , Hegger Josef
Published: May 2019

The punching shear design procedures according to current codes (e.g., Eurocode 2 or Model Code 2010) are similar. However, the predicted punching shear capacities may differ significantly depending on the background (e.g., semi‐empirical or physical) of the design provisions and the considered influences. For the evaluation and improvement of the existing provisions for flat slabs without and with high amounts of shear reinforcement, a large number of punching test series on reinforced concrete flat slabs is available in the literature. Nevertheless, the evaluation of the code equations for the design of the shear reinforcement (failure inside the shear‐reinforced zone) is still not possible since only few punching tests on flat slabs with low and medium amounts of shear reinforcement have been conducted.

To investigate the punching shear behavior of flat slabs with a varying amount of shear reinforcement, three systematic test series without and with stirrups as shear reinforcement were conducted. The experimental program included three reference tests without and eight tests with low and medium amounts of shear reinforcement. In the tests, the amount of shear reinforcement was varied by changing the stirrup diameter only. Further investigated influences were the shear span‐depth ratio and the effective depth. The results of the test series are discussed and compared to the predictions according to Eurocode 2, Model Code 2010 and the draft of the second generation of Eurocode 2.
On the chaos bound in rotating black holes
Authors: Jahnke Viktor , Kim Keun-Young , Yoon Junggi
Published: May 2019

Abstract

We study out-of-time-order correlators (OTOCs) of rotating BTZ black holes using two different approaches: the elastic eikonal gravity approximation, and the Chern-Simons formulations of 3-dimensional gravity. Within both methods the OTOC is given as a sum of two contributions, corresponding to left and right moving modes. The contributions have different Lyapunov exponents,

$$ {\lambda}_L^{\pm }=\frac{2\pi }{\beta}\frac{1}{1\mp \ell \Omega} $$

λ
L
±

=

2
π

β

1

1
∓
ℓ
Ω

, where Ω is the angular velocity and ℓ is the AdS radius. Since

$$ {\lambda}_L^{-}\le \frac{2\pi }{\beta}\le {\lambda}_L^{+} $$

λ
L
−

≤

2
π

β

≤

λ
L
+

, there is an apparent contradiction with the chaos bound. We discuss how the result can be made consistent with the chaos bound if one views the parameters β
± = β(1 ∓ ℓΩ) as the effective inverse temperatures of the left and right moving modes.
b − τ Yukawa unification in SUSY SU(5) with mirage mediation: LHC and dark matter implications
Authors: Raza Shabbar , Shafi Qaisar , Ün Cem Salih
Published: May 2019

Abstract

We consider a class of b − τ Yukawa unified Supersymmetric (SUSY) SU(5) GUTs, in which the asymptotic gaugino M
1,2,3 masses are generated through the mirage mediated supersymmetry breaking, which is a combination of the gravity and anomaly mediation. Due to the contributions from the anomaly contribution, M
3 is always lighter than M
1 and M
2, and consequently for the range of asymptotic masses considered, the gluino mass

$$ {m}_{\tilde{g}} $$

m

g
˜

at low scale is bounded from above at about 4 TeV. We realize two different regions, in one of which the MSSM μ−term is less than about 3 TeV. This region yields a stop mass up to 5 TeV, and the stop mass is nearly degenerate with the LSP neutralino for mass around 0.8 to 1.7 TeV. A stau mass can be realized up to about 5 TeV, and the stau mass is approximately degenerate with the LSP neutralino for mass around 2 to 3 TeV. In addition, an A-funnel solution with

$$ {m}_A\approx 2{m}_{{\tilde{\chi}}_1^0} $$

m
A

≈
2

m

χ
˜

1
0

and

$$ {m}_{{\tilde{\chi}}_1^0}\sim 700-900 $$

m

χ
˜

1
0

∼
700
−
900

GeV is realized. These three cases yield LSP dark matter abundance in accordance with observations. A second region, on the other hand, arises for

$$ {m}_{\tilde{g}}\lesssim 1.1{m}_{{\tilde{\chi}}_1^0} $$

m

g
˜

≲
1.1

m

χ
˜

1
0

. The μ−term is rather large (≳20 TeV), and the LSP neutralino is a bino-wino mixture. The gluino mass (∼ 0.8−1.2 TeV) is nearly degenerate with the LSP neutralino mass and hence, the gluino-neutralino coannihilation processes play a role in reducing the relic abundance of LSP neutralino down to ranges allowed by the current WMAP measurements. The two regions above can be distinguished through the direct detection experiments. The first region with relatively low μ values yields Higgsino-like DM, whose scattering on the nucleus typically has a large cross-section. We find that such solutions are still allowed by the current results from the LUX experiment, and they will be severely tested by the LUX-Zeplin (LZ) experiment. The second region contains bino-wino DM whose scattering cross-section is relatively low. These solutions are harder to rule out in the foreseeable future.
Ethical Governance: Insight from the Islamic Perspective and an Empirical Enquiry
Authors: Ghafran Chaudhry , Yasmin Sofia
Published: May 2019

Charity governance is undergoing a crisis of confidence. In this paper, we suggest an alternative approach to how governance could be perceived and conceptualized by considering the ethical notions of governance embedded in religious enquiry, with a specific focus on the Islamic perspective of governance. We firstly develop an ethical framework for charity governance, utilizing insight from the Islamic perspective. Secondly, we undertake an empirical study to assess the experience of governance within Islamic charity organizations. Our theoretical framework provides a comprehensive approach to viewing organizational governance with an emphasis on governance as a mechanism for working towards social justice and the public good. However, our empirical findings reveal an ‘ethical gap’ between the ideals of the Islamic Ethical Framework and the reality of governance practice within Muslim charity organizations. We consider the implications of these findings and outline avenues for future research.
A VBA module simulation for finding optimal lag order in time series models and its use on teaching financial data computation
Authors: Mustafa Alan , Hatemi-J Abdulnasser
Published: May 2019

In this study, a tool has been designed and developed for learning about the concept of lag order within a dynamic model, which can be used in any teaching classes on statistics and financial data computation. To show a solution for a complex and multi-step process of finding the optimal lag order for multiple variables data series based on an information criterion a module using Visual Basic for Applications (VBA) for Microsoft Excel (MS Excel) is being developed. This module can be used for estimating a multivariate dynamic model as well as determining the optimal lag order of such a model.
Conceptual framework of a skill-based interactive employee engaging system: In the Context of Upskilling the present IT organization
Authors: Nair Siddarth , Kaushik Abhishek , Dhoot Harnaik
Published: May 2019

Skills form an integral part of an organization for its efficient functioning. This research study investigates mechanisms to actively persuade employees and organizations to change their attitudes and perspectives towards skills through the design and implementation of a skill-based system. The aim of the project is to know if we can create a skill-focused climate in a software organization through a software system proposed by the researcher and if such a system will help in utilizing in-house employees for new opportunities rather than hiring new employees. Feedback was collected on the proposed skill-based system from software professionals and human resource managers through an online survey. Findings reveal that the proposed skill-based system will create a skill-focused climate in a software organization and also help in better utilization of internal employees for new skill requirements rather than directly hiring external employees.
The Mediating Role of Brand Knowledge on Employees’ Brand Citizenship Behaviour: Does Organizational Tenure Matter?
Authors: Van Nguyen Long Thang , Lu Vinh Nhat , Hill Sally Rao , Conduit Jodie
Published: May 2019

Brand knowledge is a critical factor for employee ‘living the brand’. However, literature of employee brand knowledge remains underexplored. Drawing from information processing theory and the motivation and job design perspective, this study investigates the role of brand knowledge and employee organizational tenure in the development of an internal brand and specifically its impact on employee brand citizenship behaviour. We collect data from a sample of 257 employees in branded service providers in hospitality sector in Vietnam. The results indicate the influence of brand leadership and internal branding on employee brand citizenship behaviour through brand knowledge of service employees. These findings contribute to our understanding of the relationship-mediated theory of internal marketing, and further explain the role of leaders as knowledge facilitators when building a brand ethos among employees. Further, the service tenure of the employees was found to moderate the relationships between the antecedents and brand knowledge, demonstrating that the impact of these internal brand building activities dissipates over time; highlighting the challenge organizations face in sustaining brand citizenship behaviour among employees.
The Dutch and the Second British Empire in the Early Nineteenth-Century Indian Ocean World
Authors: Wilson James David
Published: May 2019

During the French Revolutionary and Napoleonic Wars, the British Empire grew through its invasion of Dutch colonies around the Indian Ocean rim. The incursions entwined British and Dutch politics, cultures, and social networks. These developments were significant for the Dutch East Indies, but have received relatively little attention in histories of the Second British Empire. In light of recent interest in Anglo-Dutch interaction, connectivity across empires, and the uses of prosopography to question the boundaries of imperial history, this article uses Dutch biographies to interrogate the relationship between the politics of liberal reform and despotism in the Cape Colony and Java under the British. A dialectic between despotism and liberalism dominates the Second Empire's historiography. Conversely, tracing the biographies of two interstitial figures who passed between the Dutch Empire and that of Britain shows how despotism and reform were connected. The Dutch drew notions of reform from their social networks into the Cape and Java through their manipulation of loyalist rhetoric. Concurrently, the use of such rhetoric legitimized societies and controls linked to the entrenchment of autocracy. This article thus reveals links between connectivity and control in Britain's Indian Ocean empire.
Puppy Love: Domestic Science, “Women's Work,” and Canine Care
Authors: Quick Tom
Published: May 2019

The health and well-being of pets became a significant matter of medical and scientific concern during the first decades of the twentieth century. Addressing the case of dogs, this article contends that this circumstance was not primarily a consequence of developments internal to veterinary practice but rather emerged from the broader-based domestic-science movement. The elaboration of scientifically oriented approaches to dog care signals the incorporation of pets within a maternal ideal that emphasized care and efficiency as domestic virtues. Via consideration of canine milk foods, women-led canine medical institutions, canine-concerned domestic workers, and rationalist approaches to kennel design, the article demonstrates that dogs should be placed alongside such established objects of domestic scientific reform as children, homes, and human bodies. Moreover, it shows that scientific reconceptualizations of dogs relied on an extensive network of (primarily women) laborers that included food producers, nursing staff, kennel attendants, and breeders. The article thereby contributes to a growing body of scholarship highlighting ways in which the domestic-science movement forged new scientific objects and practices around the turn of the twentieth century. By the 1930s, dogs were routinely being upheld as exemplars of the kinds of homely existence made possible by scientifically informed approaches to domestic living.
“Here Is a Good Boke to Lerne”: Practical Books, the Coming of the Press, and the Search for Knowledge, ca. 1400–1560
Authors: Reynolds Melissa
Published: May 2019

This article compares the circulation and reception of useful knowledge—from medical and craft recipes to prognostications and agricultural treatises—in late medieval English manuscripts and early printed practical books. It first surveys the contents and composition of eighty-eight fifteenth-century vernacular practical manuscripts identified in significant collections in the United States and United Kingdom. Close analysis of four of these late medieval practical miscellanies reveals that their compilers saw these manuscripts as repositories for the collection of an established body of useful knowledge. The article then traces the transmission of these medieval practical texts in early printed books. As the pressures of a commercial book market gradually transformed how these practical texts were presented, readers became conditioned to discover “new” knowledge in the pages of printed books. The introduction to England of the “book of secrets” in 1558 encouraged readers to hunt for “secrets” in unpublished medieval manuscripts, ensuring that these century-old sources would remain important sites for useful knowledge well into the early modern era.
Comparison of the isotope dilution method for determination of the ileal endogenous amino acid losses with labelled diet and labelled pigs
Authors: Hess Vincent , Ganier Philippe , Thibault Jean-Noel , Sève Bernard
Published: May 2019

The aims of the present study were first to compare the amino acid dilution method performed using labelled animals with that using labelled diets, and second to determine real digestibilities and total ileal endogenous losses of N and amino acids. Two diets containing pea cultivars (Solara and Amino) and a protein-free diet were compared in a 3 × 3 Latin-square experiment. The three pigs were each prepared with an ileo-rectal anastomosis and were continuously infused with [1-13C]leucine. For each cultivar,15N-labelled and unlabelled diets were formulated. The real digestibility and endogenous losses of leucine were higher when obtained by labelling the pig than by labelling the foodstuff. This was due either to the inadequate estimation of the endogenous protein enrichment in the first case or to the importance of dietary N recycling in the second case. However, in both cases the ileal endogenous losses of N and amino acids were higher than the basal losses determined with the protein-free diet. There were significant differences between the two pea cultivars in terms of phenylalanine and leucine when measured with labelled diets. It is suggested that, although ileal endogenous losses may be underestimated, using labelled feedstuffs is of great interest due to the direct estimation of the individual amounts of amino acids.
High-dose folic acid supplementation in rats: effects on gestation and the methionine cycle
Authors: Achón M. , Alonso-Aperte E. , Reyes L. , Úbeda N. , Varela-Moreiras G.
Published: May 2019

There is new evidence that a good folate status may play a critical role in the prevention of neural-tube defects and in lowering elevated homocysteine concentrations. This adequate folate status may be achieved through folic acid dietary supplementation. Folate is a water-soluble vitamin with a low potential toxicity. However, the possible consequences of long-term high-dose folic acid supplementation are unknown, especially those related to the methionine cycle, where folate participates as a substrate. With the aim of evaluating such possible effects, four groups of Wistar rats were classified on the basis of physiological status (virgin v. pregnant) and the experimental diet administered (folic-acid-supplemented, 40 mg/kg diet v. control, 2 mg folic acid/kg diet). Animals were fed on the diets for 3 weeks. Results showed that gestation outcome was adequate in both groups regardless of the dietary supplementation. However, there were reductions (P < 0·001) in body weight and vertex-coccyx length in fetuses from supplemented dams v. control animals. Folic acid administration also induced a higher (P < 0·01) S-adenosylmethionine : S-adenosylhomocysteine value due to increased S-adenosylmethionine synthesis (P < 0·01). However, hepatic DNA methylation and serum methionine concentrations remained unchanged. Serum homocysteine levels were reduced in supplemented dams (P < 0·05). Finally, pregnancy caused lower serum folate, vitamin B6 and vitamin B12 levels (P < 0·05). Folic acid administration prevented the effect of pregnancy and raised folate levels in dams, but did not change levels of vitamins B12 and B6. These new findings are discussed on the basis of potential benefits and risks of dietary folic acid supplementation.
Whole small fish as a rich calcium source
Authors: Larsen Torben , Thilsted Shakuntala H. , Kongsbak Katja , Hansen Marianne
Published: May 2019

The present rat balance study investigated Ca availability from the whole indigenous small fish species, mola (Amblypharyngodon mola) from Bangladesh and from skimmed milk. Four groups of six young male rats each were fedad libitumwith diets containing either small fish or milk, at 100 or 160 g crude protein/kg diet dry matter. The study was conducted for 28 d and faeces and urine samples were collected in two balance periods: days 8–14 and 22–28. The Ca and N contents of the diets, faeces and urine were analysed. Ca intake, fractional Ca absorption and Ca retention in relation to N retention were measured. Digestibility and protein utilization of the experimental diets, weight gain of the rats, femur bone weight and mineral composition as well as bone alkaline phosphatase activity were also determined. It was concluded from the values of these variables that Ca from small fish with bones was available and appeared to be a useful Ca source in rats, though perhaps not as available as Ca from milk. This study suggests that small fish with bones may be an important source of Ca in human diets. Promotion of the production and consumption of small fish in population groups with low intakes of milk and milk products should therefore be encouraged.