Cuprates exhibit antiferromagnetic, charge density wave (CDW), and high-temperature superconducting ground states that can be tuned by means of doping and external magnetic fields. However, disorder ...generated by these tuning methods complicates the interpretation of such experiments. Here, we report a high-resolution inelastic x-ray scattering study of the high-temperature superconductor YBa
Cu
O
under uniaxial stress, and we show that a three-dimensional long-range-ordered CDW state can be induced through pressure along the
axis, in the absence of magnetic fields. A pronounced softening of an optical phonon mode is associated with the CDW transition. The amplitude of the CDW is suppressed below the superconducting transition temperature, indicating competition with superconductivity. The results provide insights into the normal-state properties of cuprates and illustrate the potential of uniaxial-pressure control of competing orders in quantum materials.
It is well known that superderivation of a Lie superalgebra is certain generalization of derivation of a Lie algebra. This paper is devoted to investigate the structure and dimension of ...superderivation algebra Der(G) of G where G is a direct sum of two finite dimensional Lie superalgebras L and K having no non-trivial common direct factor. We also introduce some of its subsuperalgebras. Moreover, we create a condition which shows the isomorphism between superderivation of direct sum and direct sum of superderivations of two Lie superalgebras. Later on, we take G as a semidirect sum of two Lie superalgebras and obtain the structure of
which is a subsuperalgebra of Der(G) that contains those superderivations mapping K to itself. Finally, we give some conditions under which
is also a semidirect sum.
The present study includes the fabrication and characterization and an investigation of the electrical transport properties of nanocomposites of n-PANI and graphene oxide (GO). The samples were ...prepared by loading different weight percentages
of GO during the chemical oxidative
polymerization of aniline monomers. Structural characterization by XRD, FTIR, FESEM,
confirmed that the nanocomposites exhibited superior morphology and thermal stability. The transport properties were studied by measuring the variation of conductivity with temperature
,
-
characteristics and the fundamental response
at different temperatures
. The dc conductance
showed a transition from insulator type behavior to weakly temperature dependent behavior at temperature
, which decreased with increasing
. The
-
characteristics were generally nonlinear and the nonlinearity increased with decreasing temperature. Moreover, at temperatures
≥
, the characteristics showed saturation of voltage for higher values of current, similar to Zener diodes. At lower temperatures (
≤
), a voltage maximum occurred, similar to thyristors. This behavior leads to the possibility of fabricating devices containing these nanocomposites. We have tried to analyze these results using the framework of scaling theory and the concept of inter-chain hopping conduction and tunneling between conducting grains separated by insulating regimes in the nanocomposite.
Banda Aceh was an area hit by earthquake and tsunami. In 2009 the government sought the improvement of preparedness through education sector. This effort has been done by launching the disaster ...preparedness school program or SSB. This paper aims at investigate the degree of preparedness of school community in encountering the danger of earthquake and tsunami and the factors affected the preparedness. This study used the survey techniques; the sample consisted of students, teachers, and the principals. To analyse the data, independent t-test and linear regression was used. The result shows that the SSB community and non-SSB community have the preparedness in the degree of highly prepared. The independent t-test result shows that there is no significant difference between the SSB community and non-SSB community in their degree of preparedness. The effort to maintain the degree of preparedness can be done by increasing the intensity of preparedness training activity and socialization of the benefit of preparedness at school environment and increasing the role of Geographic teacher in preparedness activity on school community.
Aminoacylation is a vital step of natural biosynthesis of peptide. Correct aminoacylation is a necessary prerequisite for the elimination of noncognate amino acids such as d-amino acids. In the ...present work, we studied the fidelity mechanism of histidine (His) activation (first step of aminoacylation reaction) using a combined quantum mechanical/semiempirical method based on a model of crystal structure of the oligomeric complex of histidyl-tRNA synthetase (HisRS) from Escherichia coli. The study of the variation in the energy during the mutual approach of the His and ATP to form adenylate shows that the surrounding nanospace of synthetase confines the reactants (l-His and ATP) and proximally places in a geometry suitable for the in-line nucleophilic attack. The significantly higher energy of the energy surface of the model containing d-His is due to unfavorable interaction of d-His with ATP and surrounding residues. This indicates that the network of interaction (principally electrostatic) is highly unfavorable when d-amino acid is incorporated. The reorganization of the surrounding nanospace can lower the unfavorable nature of the intermolecular energy surface of d-His and surrounding residues. However, such a rearrangement requires large-scale structural reorganization of the synthetase structure and is unfavorable. The variation in the bond angles and distances in going from the reactant state to the product state via transition state confirms the mechanism of nucleophilic attack and concomitant inversion of oxygen atoms around α-phosphorus (α-P). Calculation of the electrostatic potential indicates that in addition to the Mg2+ the Arg residues in the active site facilitate the nucleophilic attack by reducing the negative charge distributed over the oxygen atoms attached to the α-P of ATP. Arg 259 residue has a role similar to that played by the two Mg2+ cations as this residue is in close proximity of the α-P of ATP. Arg 113 also facilitates the reduction of the negative charge on the other side of the reaction center. The favorable electrostatic interaction of the Arg 259 with ATP and His is also concluded from the calculation of the binding energy. The Arg 259 anchors the carboxylic acid group of His and the oxygen atom of the α-phosphate group during the progress of reaction. Consequently, Arg 259 plays an important catalytic role in the activation step rather than merely reducing the negative charge density over the ATP.
We measured the real part of ac conductance Σ(x,f) or Σ(T,f) of iron-doped mixed-valent polycrystalline manganite oxides LaMn1−xFexO3 as a function of frequency f by varying initial conductance Σ0 by ...quenched disorder x at a fixed temperature T (room) and by temperature T at a fixed quenched disorder x. At a fixed temperature T, Σ(x,f) of a sample with fixed x remains almost constant at its zero-frequency dc value Σ0 at lower frequency. With increase in f, Σ(x,f) increases slowly from Σ0 and finally increases rapidly following a power law with an exponent s at high frequency. Scaled appropriately, the data for Σ(T,f) and Σ(x,f) fall on the same universal curve, indicating the existence of a general scaling formalism for the ac conductivity in disordered systems. The characteristic frequency fc at which Σ(x,f) or Σ(T,f) increases for the first time from Σ0 scales with initial conductance Σ0 as , where xf is the onset exponent. The value of xf is nearly equal to one and is found to be independent of x and T. Further, an inverse relationship between xf and s provides a self-consistency check of the systematic description of Σ(x,f) or Σ(T,f). This apparent universal value of xf is discussed within the framework of existing theoretical models and scaling theories. The relevance to other similar disordered systems is also highlighted.
The complex relationship between microbiota, human physiology, and environmental perturbations has become a major research focus, particularly with the arrival of culture-free and high-throughput ...approaches for studying the microbiome. Early enthusiasm has come from results that are largely correlative, but the correlative phase of microbiome research has assisted in defining the key questions of how these microbiota interact with their host. An emerging repertoire for engineering the microbiome places current research on a more experimentally grounded footing. We present a detailed look at the interplay between microbiota and host and how these interactions can be exploited. A particular emphasis is placed on unstable microbial communities, or dysbiosis, and strategies to reestablish stability in these microbial ecosystems. These include manipulation of intermicrobial communication, development of designer probiotics, fecal microbiota transplantation, and synthetic biology.
Preparedness in facing disaster becomes a must when living in disaster-prone areas. West Java province, Indonesia, has frequent disasters such as tsunamis, earthquakes and landslides. The level of ...preparedness to be important in minimizing the loss of life in case of disaster. This research aim at analyse the community preparedness in the face of the three disasters that often occur in their respective areas in West Java province. This research uses descriptive quantitative approach, with the survey method. The results showed that the level of preparedness of the community in the district of Pangandaran to the tsunami disaster has categorized Very Ready, people in Tasikmalaya regency for earthquake disaster has categorized Ready, and society in Garut for landslides has categorized Less Ready. In conclusion, there are significant differences between community preparedness in Pangandaran, Tasikmalaya and Garut regencies.
The present study makes an effort to understand the damage of earthen dams under static and seismic loading condition. To make the investigation more realistic, behaviour of earthen dams considering ...the occurrence of a phreatic line indicating the submerged zone due to seepage within the dam body is considered. In case of earthen dams, homogeneous or nonhomogeneous, the consideration of the occurrence of a phreatic line or seepage line through the dam body is an important part of the earthen dam design methodology. The impervious material properties in the submerged zone below the phreatic line due to seepage may differ a lot in magnitudes as compared to the value of the same materials lying above this line. Hence, to have the exact stress distribution scenarios within the earthen dam, the different material properties above and below the phreatic line are considered in this present study. The study is first carried out by two-dimensional as well as three-dimensional finite element analysis under static loading condition. The work is further extended to observe the effect of seepage due to the consideration of the phreatic line on dynamic characteristics of earthen dams. Free vibration analysis and seismic analysis based on the Complete Quadratic Combination (CQC) method by considering twodimensional and three-dimensional modeling are carried out to present the frequencies, mode shapes and the stress distribution pattern of the earthen dam.
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