2,032 research outputs found

    Thermal response of nonequilibrium RC-circuits

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    We analyze experimental data obtained from an electrical circuit having components at different temperatures, showing how to predict its response to temperature variations. This illustrates in detail how to utilize a recent linear response theory for nonequilibrium overdamped stochastic systems. To validate these results, we introduce a reweighting procedure that mimics the actual realization of the perturbation and allows extracting the susceptibility of the system from steady state data. This procedure is closely related to other fluctuation-response relations based on the knowledge of the steady state probability distribution. As an example, we show that the nonequilibrium heat capacity in general does not correspond to the correlation between the energy of the system and the heat flowing into it. Rather, also non-dissipative aspects are relevant in the nonequilbrium fluctuation response relations.Comment: 2 figure

    Reduced Order Modeling for Heston Stochastic Volatility Model

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    In this paper we compare two model order reduction techniques, the Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD), for Heston's option pricing model. The full order model is obtained by discontinuous Galerkin discretization in space and backward Euler in time. Numerical results for butterfly spread, European and digital call options reveal that in general DMD requires more modes than the POD modes as expected at the same level of accuracy. However, the speed-up factors are much higher for DMD than POD due to the equation free nature of the DMD.Comment: arXiv admin note: text overlap with arXiv:1606.0838

    Acute epidural hematoma manifesting with monoplegia in a child: Case report

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    A seven year-old girl presented with left sided painlessmonoplegia at the lower extremity after falling from twometers height. Cranial computed tomography showedright sided fronto-parietal epidural hematoma. Urgentdecompressive craniotomy for the evacuation of the hematomawas performed. Patient discharged two weeksafter admission with minimal loss of muscle strength.Fronto-parietal epidural hematomas may also manifestwith monoplegia and early evacuation should be standardmanagement. J Clin Exp Invest 2013; 4 (2): 223-225Key words: Epidural hematoma, monoplegia, computedtomograph

    A general fluctuation-response relation for noise variations and its application to driven hydrodynamic experiments

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    The effect of a change of noise amplitudes in overdamped diffusive systems is linked to their unperturbed behavior by means of a nonequilibrium fluctuation-response relation. This formula holds also for systems with state-independent nontrivial diffusivity matrices, as we show with an application to an experiment of two trapped and hydrodynamically coupled colloids, one of which is subject to an external random forcing that mimics an effective temperature. The nonequilibrium susceptibility of the energy to a variation of this driving is an example of our formulation, which improves an earlier version, as it does not depend on the time-discretization of the stochastic dynamics. This scheme holds for generic systems with additive noise and can be easily implemented numerically, thanks to matrix operations

    Effective field theory approach to Casimir interactions on soft matter surfaces

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    We utilize an effective field theory approach to calculate Casimir interactions between objects bound to thermally fluctuating fluid surfaces or interfaces. This approach circumvents the complicated constraints imposed by such objects on the functional integration measure by reverting to a point particle representation. To capture the finite size effects, we perturb the Hamiltonian by DH that encapsulates the particles' response to external fields. DH is systematically expanded in a series of terms, each of which scales homogeneously in the two power counting parameters: \lambda \equiv R/r, the ratio of the typical object size (R) to the typical distance between them (r), and delta=kB T/k, where k is the modulus characterizing the surface energy. The coefficients of the terms in DH correspond to generalized polarizabilities and thus the formalism applies to rigid as well as deformable objects. Singularities induced by the point particle description can be dealt with using standard renormalization techniques. We first illustrate and verify our approach by re-deriving known pair forces between circular objects bound to films or membranes. To demonstrate its efficiency and versatility, we then derive a number of new results: The triplet interactions present in these systems, a higher order correction to the film interaction, and general scaling laws for the leading order interaction valid for objects of arbitrary shape and internal flexibility.Comment: 4 pages, 1 figur

    Simultaneous occurence of compound odontoma and arrested root formation as developmental disturbances after maxillofacial trauma : a case report

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    Traumatic injury to a primary tooth and/or a bone fracture has the potential to damage the underlying permanent tooth germ which may disturb its development. The extent of the malformation depends on the developmental stage of the permanent tooth and the intensity of the trauma. The presence of infection may be a predictive factor for these abnormalities. Open surgical procedures can also potentially cause impaction and developmental disturbances. Several developmental alterations such as discolouration, hypoplasia, crown dilaceration, root angulation or dilaceration, sequestration of permanent tooth buds and disturbance in eruption have been reported in permanent teeth after trauma. However, odontoma-like malformations and partial or complete arrest of root formation are rare complications developed after trauma. This article presents a rare case with simultaneous occurrence of an odontoma-like malformation and complete and partial arrested root formations as the results of maxillofacial trauma. Almost all pediatric fractures must be managed with closed reduction as much as possible. However, if it is necessary to perform an open reduction, careful attention must be paid during placement of the osteosynthetic plates and screws; and tooth bud development must be followed periodically

    ABO and Rh Blood Groups Distribution in Yozgat City, Turkey

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    Objective: In this retrospective study, we included 5257 healthy participants who admitted to Yozgat Government Hospital Blood Bank and Bozok University Blood Bank for several reasons to determine A, B, 0, AB blood groups and Rhesus (Rh) positivity ratios between January 2007 and April 2013. Methods: We recorded their blood group types, age and gender from the hospital data. 2430 females, 2827 males totally 5257 participants were included to our study. Results: 2330 (44.3%) persons were A blood group, 837 (15.9%) were B group, 1665 (31.7%) were 0 and 425 (%8.1) were AB group. Rh positivity ratio of our study group was 88%. Blood group frequency of Yozgat city is similar to other cities and the general population of our country, Turkey. Conclusion: Knowing the blood group is important for the blood recruitment in our region. J Clin Exp Invest 2014; 5 (2): 169-17
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