3,824 research outputs found
Could CuB be the site of redox linkage in cytochrome c oxidase?
This paper explores the proton pumping function of cytochrome c oxidase [ferrocytochrome-c:oxygen oxidoreductase (EC 1.9.3.1)] based upon redox linkage at the "high-potential" CU(B) center. A model is proposed that is derived from a redox-linked ligand exchange mechanism previously described for the Cu(A) site. Qualitative analysis of this mechanism indicates that such a mechanism is feasible. However, the relatively short distance between Cu(B) and cytochrome a3 implies that the uncoupling electron transfers are quite facile. In addition, the position of the Cu(B) center with respect to the inner mitochondrial membrane argues against redox linkage at the Cu(B) site
Unstructured Grid Dynamical Modeling of Planetary Atmospheres using planetMPAS: The Influence of the Rigid Lid, Computational Efficiency, and Examples of Martian and Jovian Application
We present a new planetary global circulation model, planetMPAS, based on the
state-of-the-art NCAR MPAS General Circulation Model. Taking advantage of the
cross compatibility between WRF and MPAS, planetMPAS includes most of the
planetWRF physics parameterization schemes for terrestrial planets such as Mars
and Titan. PlanetMPAS also includes a set of physics that represents radiative
transfer, dry convection, moist convection and its associated microphysics for
the Jovian atmosphere. We demonstrate that, despite the rigid-lid
approximation, planetMPAS is suitable to simulate the climate systems in
Martian and Jovian atmospheres with potential application to slow-rotating
planets such as Titan. Simulations using planetMPAS show that the new model can
reproduce many aspects of the observed features on Mars and Jupiter, such as
the seasonal CO2 cycle, polar argon enrichment, zonal mean temperature, and
qualitative dust opacity on Mars, as well as the equatorial superrotation and
banded zonal wind patterns on Jupiter.Comment: Manuscript has 61 pages, 20 figures, 2 tables, submitted to Planetary
and Space Scienc
Direct Numerical Simulation Of Hypersonic Turbulent Boundary Layers. Part 2. Effect Of Wall Temperature
In this paper, we perform direct numerical simulation (DNS) of turbulent boundary layers at Mach 5 with the ratio of wall-to-edge temperature T w/T ℘ from 1.0 to 5.4 (Cases M5T1 to M5T5). The influence of wall cooling on Morkovin\u27s scaling, Walz\u27s equation, the standard and modified strong Reynolds analogies, turbulent kinetic energy budgets, compressibility effects and near-wall coherent structures is assessed. We find that many of the scaling relations used to express adiabatic compressible boundary-layer statistics in terms of incompressible boundary layers also hold for non-adiabatic cases. Compressibility effects are enhanced by wall cooling but remain insignificant, and the turbulence dissipation remains primarily solenoidal. Moreover, the variation of near-wall streaks, iso-surface of the swirl strength and hairpin packets with wall temperature demonstrates that cooling the wall increases the coherency of turbulent structures. We present the mechanism by which wall cooling enhances the coherence of turbulence structures, and we provide an explanation of why this mechanism does not represent an exception to the weakly compressible hypothesis. © 2010 Cambridge University Press
Pengaruh Metode Resitasi dalam Model Pembelajaran Kooperatif untuk Meningkatkan Hasil Belajar Materi Kalor dan Perpindahannya
The purpose of this study was to determine whether there is an effect of the recitation method in the cooperative learning model to improve the learning outcomes of heat and its transfer. This type of research was quasi-experimental. The sampling technique was purposive sampling. The samples of this research were students of class VII A and VII B of SMP Negeri 3 Bulagi. Class VII A is the experimental group and class VIIB is the control group. The learning outcome test instrument was a multiple-choice test. Based on the results of data processing, the N-gain value in the experimental group was obtained at 45.97%, which was in the medium category. Then for the control group, the N-gain value was obtained at 33.43%, which was also in the medium category. These results indicate that the learning outcomes of physics in the experimental group are higher than those in the control group. The results of statistical calculations from the average difference test using t-test (two-tailed) obtained tcount > ttable (tcount = 4.22 and ttable = 2.02) at a significance level of 5% and dk = 45, thus H0 is rejected and H1 is accepted. So, it can be concluded that there is an effect of the recitation method in the cooperative learning model to improve the learning outcomes of heat and its transfer
Pyrolytic formation of polyaromatic hydrocarbons from steroid hormones
Four steroid hormones, namely androsterone, cholesterol, estrone and estradiol, have been pyrolysed at 300, 400 and 500 °C and the pyrolysates from these have been analysed by GC-MS. The results indicate that these formed different products under the pyrolysis and most of them evolved into polycyclic aromatic hydrocarbons during their residence in the pyrolysis chamber at high temperatures. The products from the pyrolysates, at all temperatures, were analysed for similarities and differences using multivariate data analysis. The products possessed some similarities on pyrolysis at 300 °C but were entirely different when pyrolysed at 500 °C. Androsterone and cholesterol formed a higher percentage of substituted PAH than did estrone and estradiol. These compounds included carcinogens, such as phenanthrene, methylphenanthrene, fluorene and its derivatives. The side chain of cholesterol had no effect on the products formed, while the presence of the aromatic ring in estrone and estradiol led to a higher percentage of phenol and its derivatives in the pyrolysates. Furthermore, estrone was subjected to flash pyrolysis and the products formed were compared with those which resulted from the long time pyrolysis: flash pyrolysis produced small amounts of PAH
The Impact of Group Drumming on Social-Emotional Behavior in Low-Income Children
Low-income youth experience social-emotional problems linked to chronic stress that are exacerbated by lack of access to care. Drumming is a non-verbal, universal activity that builds upon a collectivistic aspect of diverse cultures and does not bear the stigma of therapy. A pretest-post-test non-equivalent control group design was used to assess the effects of 12 weeks of school counselor-led drumming on social-emotional behavior in two fifth-grade intervention classrooms versus two standard education control classrooms. The weekly intervention integrated rhythmic and group counseling activities to build skills, such as emotion management, focus and listening. The Teacher's Report Form was used to assess each of 101 participants (n = 54 experimental, n = 47 control, 90% Latino, 53.5% female, mean age 10.5 years, range 10–12 years). There was 100% retention. ANOVA testing showed that intervention classrooms improved significantly compared to the control group in broad-band scales (total problems (P < .01), internalizing problems (P < .02)), narrow-band syndrome scales (withdrawn/depression (P < .02), attention problems (P < .01), inattention subscale (P < .001)), Diagnostic and Statistical Manual of Mental Disorders-oriented scales (anxiety problems (P < .01), attention deficit/hyperactivity problems (P < .01), inattention subscale (P < .001), oppositional defiant problems (P < .03)), and other scales (post-traumatic stress problems (P < .01), sluggish cognitive tempo (P < .001)). Participation in group drumming led to significant improvements in multiple domains of social-emotional behavior. This sustainable intervention can foster positive youth development and increase student-counselor interaction. These findings underscore the potential value of the arts as a therapeutic tool
Classical Scattering in Dimensional String Theory
We find the general solution to Polchinski's classical scattering equations
for dimensional string theory. This allows efficient computation of
scattering amplitudes in the standard Liouville background.
Moreover, the solution leads to a mapping from a large class of time-dependent
collective field theory backgrounds to corresponding nonlinear sigma models.
Finally, we derive recursion relations between tachyon amplitudes. These may be
summarized by an infinite set of nonlinear PDE's for the partition function in
an arbitrary time-dependent background.Comment: 15 p
Quantum Group as Semi-infinite Cohomology
We obtain the quantum group as semi-infinite cohomology of the
Virasoro algebra with values in a tensor product of two braided vertex operator
algebras with complementary central charges . Each braided VOA is
constructed from the free Fock space realization of the Virasoro algebra with
an additional q-deformed harmonic oscillator degree of freedom. The braided VOA
structure arises from the theory of local systems over configuration spaces and
it yields an associative algebra structure on the cohomology. We explicitly
provide the four cohomology classes that serve as the generators of
and verify their relations. We also discuss the possible extensions of our
construction and its connection to the Liouville model and minimal string
theory.Comment: 50 pages, 7 figures, minor revisions, typos corrected, Communications
in Mathematical Physics, in pres
Emergence of film-thickness- and grain-size-dependent elastic properties in nanocrystalline thin films
Molecular dynamics simulations of nanocrystalline Ni revealed that the in-plane Young’s modulus of 2.2 nm grained Ni film with ∼10 grains across its thickness was only 0.64% smaller than that of bulk, while it dropped to 24.1% below bulk value for ∼1 grain across film. This size dependence arises from the increased number of more compliant grains adjacent to the free surface. Simulations of nanocrystalline diamond revealed that the anharmonicity of the potential curve determined the sensitivity of the Young’s modulus to variations in the sample size
Recursion Relations in Liouville Gravity coupled to Ising Model satisfying Fusion Rules
The recursion relations of 2D quantum gravity coupled to the Ising model
discussed by the author previously are reexamined. We study the case in which
the matter sector satisfies the fusion rules and only the primary operators
inside the Kac table contribute. The theory involves unregularized divergences
in some of correlators. We obtain the recursion relations which form a closed
set among well-defined correlators on sphere, but they do not have a beautiful
structure that the bosonized theory has and also give an inconsistent result
when they include an ill-defined correlator with the divergence. We solve them
and compute the several normalization independent ratios of the well-defined
correlators, which agree with the matrix model results.Comment: Latex, 22 page
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