2,436 research outputs found
Variable Coefficient Third Order KdV Type of Equations
We show that the integrable subclassess of a class of third order
non-autonomous equations are identical with the integrable subclassess of the
autonomous ones.Comment: Latex file , 15 page
2+1 KdV(N) Equations
We present some nonlinear partial differential equations in 2+1-dimensions
derived from the KdV Equation and its symmetries. We show that all these
equations have the same 3-soliton structures. The only difference in these
solutions are the dispersion relations. We also showed that they pass the
Painlev\'e test.Comment: 15 page
The Economics of Reducing Package Size: Consumer response and returns to manufacturers.
Marketing, Production Economics,
Friedmann equation for brans-dicke cosmology
In the context of the Brans-Dicke scalar tensor theory of gravitation, the cosmological Friedmann equation which relates the expansion rate H of the universe to the various fractions of energy density is analyzed rigorously. It is shown that the Brans-Dicke scalar tensor theory of gravitation brings a negligible correction to the matter density component of the Friedmann equation. Besides, in addition to Omega(Lambda) and Omega(M) in the standard Einstein cosmology, another density parameter, Omega(Delta), is expected by the theory inevitably. Some cosmological consequences of such nonfamiliar cases are examined as far as recent observational results are concerned. Theory implies that if Omega(Delta) is found to be nonzero, data can favor this model and hence this theory turns out to be the most powerful candidate in place of the standard Einstein cosmological model with cosmological constant. Such a replacement will enable more accurate predictions for the rate of change of the Newtonian gravitational constant in the future
Monolithic shape-programmable dielectric liquid crystal elastomer actuators
Macroscale robotic systems have demonstrated great capabilities of high
speed, precise, and agile functions. However, the ability of soft robots to
perform complex tasks, especially in centimeter and millimeter scale, remains
limited due to the unavailability of fast, energy-efficient soft actuators that
can programmably change shape. Here, we combine desirable characteristics from
two distinct active materials: fast and efficient actuation from dielectric
elastomers and facile shape programmability from liquid crystal elastomers into
a single shape changing electrical actuator. Uniaxially aligned monoliths
achieve strain rates over 120%/s with energy conversion efficiency of 20% while
moving loads over 700 times the actuator weight. The combined actuator
technology offers unprecedented opportunities towards miniaturization with
precision, efficiency, and more degrees of freedom for applications in soft
robotics and beyond
Godel-type Metrics in Various Dimensions II: Inclusion of a Dilaton Field
This is the continuation of an earlier work where Godel-type metrics were
defined and used for producing new solutions in various dimensions. Here a
simplifying technical assumption is relaxed which, among other things,
basically amounts to introducing a dilaton field to the models considered. It
is explicitly shown that the conformally transformed Godel-type metrics can be
used in solving a rather general class of Einstein-Maxwell-dilaton-3-form field
theories in D >= 6 dimensions. All field equations can be reduced to a simple
"Maxwell equation" in the relevant (D-1)-dimensional Riemannian background due
to a neat construction that relates the matter fields. These tools are then
used in obtaining exact solutions to the bosonic parts of various supergravity
theories. It is shown that there is a wide range of suitable backgrounds that
can be used in producing solutions. For the specific case of (D-1)-dimensional
trivially flat Riemannian backgrounds, the D-dimensional generalizations of the
well known Majumdar-Papapetrou metrics of general relativity arise naturally.Comment: REVTeX4, 17 pp., no figures, a few clarifying remarks added and
grammatical errors correcte
Integrable nonlinear equations on a circle
The concept of integrable boundary value problems for soliton equations on
and is extended to bounded regions enclosed by
smooth curves. Classes of integrable boundary conditions on a circle for the
Toda lattice and its reductions are found.Comment: 23 page
Regulation by phosphodiesterase isoforms of protein kinase A-mediated attenuation of myocardial protein kinase D activation
Protein kinase D (PKD) targets several proteins in the heart, including cardiac troponin I (cTnI) and class II histone deacetylases, and regulates cardiac contraction and hypertrophy. In adult rat ventricular myocytes (ARVM), PKD activation by endothelin-1 (ET1) occurs via protein kinase Cε and is attenuated by cAMP-dependent protein kinase (PKA). Intracellular compartmentalisation of cAMP, arising from localised activity of distinct cyclic nucleotide phosphodiesterase (PDE) isoforms, may result in spatially constrained regulation of the PKA activity that inhibits PKD activation. We have investigated the roles of the predominant cardiac PDE isoforms, PDE2, PDE3 and PDE4, in PKA-mediated inhibition of PKD activation. Pretreatment of ARVM with the non-selective PDE inhibitor isobutylmethylxanthine (IBMX) attenuated subsequent PKD activation by ET1. However, selective inhibition of PDE2 [by erythro-9-(2-hydroxy-3-nonyl) adenine, EHNA], PDE3 (by cilostamide) or PDE4 (by rolipram) individually had no effect on ET1-induced PKD activation. Selective inhibition of individual PDE isoforms also had no effect on the phosphorylation status of the established cardiac PKA substrates phospholamban (PLB; at Ser16) and cTnI (at Ser22/23), which increased markedly with IBMX. Combined administration of cilostamide and rolipram, like IBMX alone, attenuated ET1-induced PKD activation and increased PLB and cTnI phosphorylation, while combined administration of EHNA and cilostamide or EHNA and rolipram was ineffective. Thus, cAMP pools controlled by PDE3 and PDE4, but not PDE2, regulate the PKA activity that inhibits ET1-induced PKD activation. Furthermore, PDE3 and PDE4 play redundant roles in this process, such that inhibition of both isoforms is required to achieve PKA-mediated attenuation of PKD activation
Composición de ácidos grasos en aceites de semillas de cáñamo de diferentes localidades de Turquía
Recent interest in hempseed as a source of food has largely focused on its oil content and fatty acid profile. The oil content and fatty acid composition (15 fatty acids) of twenty one different hempseed samples of domestic origin from north-western Turkey were monitored. The samples were obtained from seed wholesalers and local spice shops and are of unknown genetic origin. The oil content of the hempseeds ranged between 29.6 to 36.5%. Out of the 15 detected fatty acids, the omega-6 linoleic acid (18:2n-6) was predominant and fluctuated from 55.4 to 56.9%, while the omega-3 α-linolenic (18:3n-3) acid ranged from 16.5 to 20.4% and the omega-9 oleic acid (18:1n-9) ranged from 11.4 to 15.9%. Of the minor fatty acids, the highest concentrations were found for γ-linolenic acid (18:3n-6), range 0.6-1.1%, followed by stearidonic acid (18:4n-3), range 0.3-0.5%. These results show that hempseed grown in north-western Turkey provides a well balanced and rich source of dietary omega-6 and -3 essential fatty acids and appears to be a potentially valuable source of food.El reciente interés por las semillas de cáñamo como alimento se ha enfocado en su contenido en aceite y su perfil de ácidos grasos. En este estudio se analizó el contenido en aceite y composición de ácidos grasos de 21 muestras diferentes de semillas de cáñamo de origen genético desconocido en el noroeste de Turquía. El contenido en aceite de las semillas varió entre 29,6 y 36,5%. De los 15 ácidos grasos detectados, el ácido linoleico (18:2n-6) (omega-6) fue predominante y fluctuó entre 55,4 y 56,9%; el ácido α-linolénico (18:3n-3) (omega-3) entre 16,5 y 20,4%; y el ácido oleico (18:1n-9) (omega-9) entre 11,4 y 15,9%. Entre los ácidos grasos minoritarios, se encontraron las mayores concentraciones (entre 0,6 y 1,1%) para el ácido γ-linolénico (18:3n-6), seguido del ácido estearidónico (18:4n-3), entre 0,3 y 0,5%. Estos resultados muestran que las semillas de cáñamo que se cultivan en el noroeste de Turquía pueden ser un alimento potencialmente valioso y constituirían para la dieta una fuente rica y equilibrada de ácidos grasos omega-6 y -3
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