Role of mitochondria in Parkinson disease

The cause of the selective degeneration of nigrostriatal neurons in Parkinson disease (PD) has remained largely unknown. Exceptions include rare missense mutations in the alpha-synuclein gene on chromosome 4, a potentially pathogenic mutation affecting the ubiquitin pathway, and mutations in the parkin gene on chromosome 6. However, unlike classical PD, the latter syndrome is not associated with the formation of typical Lewy bodies. In contrast, a biochemical defect of complex I of the mitochondrial respiratory chain has been described in a relatively large group of confirmed PD cases. Recent cybrid studies indicate that the complex I defect in PD has a genetic cause and that it may arise from mutations in the mitochondrial DNA, Sequence analysis of the mitochondrial genome supports the view that mitochondrial point mutations are involved in PD pathogenesis. However, although mitochondria function as regulators in several known forms of cell death, their exact involvement in PD has remained unresolved. This is of relevance because classical apoptosis does not appear to play a major role in the degeneration of the parkinsonian nigra

A computational study of the thermoelectric performance of ultrathin Bi2Te3 films

The ballistic thermoelectric performance of ultrathin films of Bi2Te3, ranging in thickness from 1 to 6 quintuple layers, is analyzed using density functional theory combined with the Landauer approach. Our results show that the thinnest film, corresponding to a single quintuple layer, has an intrinsic advantage originating from the particular shape of its valence band, leading to a large power factor and figure-of-merit exceeding bulk Bi2Te3. The interaction between the top and bottom topological surface states is key. The thinnest film yields a six-fold increase in power factor compared to bulk

Steady-state heat transport: Ballistic-to-diffusive with Fourier\u27s law

It is generally understood that Fourier\u27s law does not describe ballistic phonon transport, which is important when the length of a material is similar to the phonon mean-free-path. Using an approach adapted from electron transport, we demonstrate that Fourier\u27s law and the heat equation do capture ballistic effects, including temperature jumps at ideal contacts, and are thus applicable on all length scales. Local thermal equilibrium is not assumed, because allowing the phonon distribution to be out-of-equilibrium is important for ballistic and quasi-ballistic transport. The key to including the non-equilibrium nature of the phonon population is to apply the proper boundary conditions to the heat equation. Simple analytical solutions are derived, showing that (i) the magnitude of the temperature jumps is simply related to the material properties and (ii) the observation of reduced apparent thermal conductivity physically stems from a reduction in the temperature gradient and not from a reduction in actual thermal conductivity.We demonstrate how our approach, equivalent to Fourier\u27s law, easily reproduces results of the Boltzmann transport equation, in all transport regimes, even when using a full phonon dispersion and mean-free-path distribution

A Public Good Version of the Collective Household Model: An Empirical Approach with an Application to British Household Data

In this paper we consider an empirical collective household model of time allocation for two-earner households. The novelty of this paper is that we estimate a version of the collective household model, where the internally produced goods and the externally purchased goods are assumed to be public. The empirical results suggest that: (1) Preferences of men and women differ; (2) Although there are significant individual variations, on average the utility functions of men and women are equally weighted in the household utility function; (3) Differences in the ratio of the partners' hourly wages are explanatory for how individual utilities are weighted in the household utility function. (4) The female's preference for household production is influenced by family size, but this does not hold for the male; (5) Both the male and the female have a backward-bending labor supply curve; (6) Labor-supply curves are forward-bending with respect to the partner's wage rate; (7) Our model rejects the unitary Slutsky symmetry condition.labor supply, collective household models, household behavior,

Intra-Household Work Timing: The Effect on Joint Activities and the Demand for Child Care

This study examines if couples time their work hours and how this work timing influences child care demand and the time that spouses jointly spend on leisure, household chores and child care. By using a innovative matching strategy, this studies identifies the timing of work hours that cannot be explained by factors other than the partners' potential to communicate on the timing of their work. The main findings are that couples with children create less overlap in their work times and this effect is more pronounced the younger the children. We find evidence for a togetherness preference of spouses, but only for childless couples. Work timing also influences the joint time that is spent on household chores, but the effect is small. Finally, work timing behavior affects the demand for informal child care, but not the demand for formal child care.labor supply, work timing, time allocation

Approach to the extremal limit of the Schwarzschild-de Sitter black hole

The quasinormal-mode spectrum of the Schwarzschild-de Sitter black hole is studied in the limit of near-equal black-hole and cosmological radii. It is found that the mode_frequencies_ agree with the P"oschl-Teller approximation to one more order than previously realized, even though the effective_potential_ does not. Whether the spectrum approaches the limiting one uniformly in the mode index is seen to depend on the chosen units (to the order investigated). A perturbation framework is set up, in which these issues can be studied to higher order in future.Comment: REVTeX4, 4pp., no figures. N.B. "Alec" is my first, and "Maassen van den Brink" my family name. v2: added numerical verificatio

Hamiltonian and Linear-Space Structure for Damped Oscillators: I. General Theory

The phase space of $N$ damped linear oscillators is endowed with a bilinear map under which the evolution operator is symmetric. This analog of self-adjointness allows properties familiar from conservative systems to be recovered, e.g., eigenvectors are "orthogonal" under the bilinear map and obey sum rules, initial-value problems are readily solved and perturbation theory applies to the_complex_ eigenvalues. These concepts are conveniently represented in a biorthogonal basis.Comment: REVTeX4, 10pp., 1 PS figure. N.B.: `Alec' is my first name, `Maassen van den Brink' my family name. v2: extensive streamlinin

Unconventional Gravitational Excitation of a Schwarzschild Black Hole

Besides the well-known quasinormal modes, the gravitational spectrum of a Schwarzschild black hole also has a continuum part on the negative imaginary frequency axis. The latter is studied numerically for quadrupole waves. The results show unexpected striking behavior near the algebraically special frequency $\Omega=-4i$. This reveals a pair of unconventional damped modes very near $\Omega$, confirmed analytically.Comment: REVTeX4, 4pp, 6 EPS figure files. N.B.: "Alec" is my first, and "Maassen van den Brink" my family name. v2: better pole placement in Fig. 1. v3: fixed Refs. [9,20]. v4: added context on "area quantum" research; trimmed one Fig.; textual clarification

Quantum Manipulations of Small Josephson Junctions

Low-capacitance Josephson junction arrays in the parameter range where single charges can be controlled are suggested as possible physical realizations of the elements which have been considered in the context of quantum computers. We discuss single and multiple quantum bit systems. The systems are controlled by applied gate voltages, which also allow the necessary manipulation of the quantum states. We estimate that the phase coherence time is sufficiently long for experimental demonstration of the principles of quantum computation.Comment: RevTex, 15 pages,4 postscript figures, uuencoded, submitted to Phys. Rev. Lett., estimates of the experimental parameters correcte