Automated method for study of drug metabolism

Commercially available equipment can be modified to provide automated system for assaying drug metabolism by continuous flow-through. System includes steps and devices for mixing drug with enzyme and cofactor in the presence of pure oxygen, dialyzing resulting metabolite against buffer, and determining amount of metabolite by colorimetric method

Conversion of acetate to lipids and co2 by liver of rats exposed to acceleration stress

Acetate conversion to lipids and carbon dioxide by exposure of rat liver to acceleration stres

Computer system for monitoring radiorepirometry data

System monitors expired breath patterns simultaneously from four small animals after they have been injected with carbon-14 substrates. It has revealed significant quantitative differences in oxidation patterns of glucose following such mild treatments of rats as a change in diet or environment

Convergence of continuous-time quantum walks on the line

The position density of a "particle" performing a continuous-time quantum walk on the integer lattice, viewed on length scales inversely proportional to the time t, converges (as t tends to infinity) to a probability distribution that depends on the initial state of the particle. This convergence behavior has recently been demonstrated for the simplest continuous-time random walk [see quant-ph/0408140]. In this brief report, we use a different technique to establish the same convergence for a very large class of continuous-time quantum walks, and we identify the limit distribution in the general case.Comment: Version to appear in Phys. Rev.

Comparison of prediction methods and studies of relaxation in hypersonic turbulent nozzle-wall boundary layers

Turbulent boundary layer measurements on axisymmetric hypersonic nozzle wall

Deuxième contribution é l'étude de Formica bruni Kutter (Hymenoptera, Formicidae)

Formica bruni décrite en 1966 par Kutter appartient au sous-genre Coptoformica Müll. connue de Forel sous le nom de Formica pressilabris "un peu exsecta ". La biologie de cette espèce est demeurée inconnue jusqu'à nous jours. La découverte d'une nouvelle station au Bois de Chênes, près de Nyon (Vaud, Suisse), nous a poussé à entreprendre une série de travaux afin de savoir dans quelle mesure cette espèce diffère des autres espèces de Coptoformica. La zone étudiée comportait 61 nids en 1978, 18 nids habités par 7 sociétés en 1983 et 2 nids occupés par deux sociétés en juillet 1984. F. bruni est une espèce vraisemblablement polygyne et facultativement polycalique; aucune agressivité n'a été observée entre les sociétés qui, d'autre part, exploitent en commun un même territoire trophique. Les sociétés sont de petites tailles et leur territoire exploité ainsi que leur taux d'activité dépendent principalement de la quantité de nourriture à disposition. Différents facteurs susceptibles de la quasi extinction de cette espèce dans cette station sont discutés (fauchage, pâturage, etc...)

Spectral absorption of visual pigments in stomatopod larval photoreceptors

Larval stomatopod eyes appear to be much simpler versions of adult compound eyes, lacking most of the visual pigment diversity and photoreceptor specializations. Our understanding of the visual pigment diversity of larval stomatopods, however, is based on four species, which severely limits our understanding of stomatopod eye ontogeny. To investigate several poorly understood aspects of stomatopod larval eye function, we tested two hypotheses surrounding the spectral absorption of larval visual pigments. First, we examined a broad range of species to determine if stomatopod larvae generally express a single, spectral class of photoreceptor. Using microspectrophotometry (MSP) on larvae captured in the field, we found data which further support this long-standing hypothesis. MSP was also used to test whether larval species from the same geographical region express visual pigments with similar absorption spectra. Interestingly, despite occupation of the same geographical location, we did not find evidence to support our second hypothesis. Rather, there was significant variation in visual pigment absorption spectra among sympatric species. These data are important to further our understanding of larval photoreceptor spectral diversity, which is beneficial to ongoing investigations into the ontogeny, physiology, and molecular evolution of stomatopod eyes. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00359-015-1063-y) contains supplementary material, which is available to authorized users

The delayed uncoupled continuous-time random walks do not provide a model for the telegraph equation

It has been alleged in several papers that the so called delayed continuous-time random walks (DCTRWs) provide a model for the one-dimensional telegraph equation at microscopic level. This conclusion, being widespread now, is strange, since the telegraph equation describes phenomena with finite propagation speed, while the velocity of the motion of particles in the DCTRWs is infinite. In this paper we investigate how accurate are the approximations to the DCTRWs provided by the telegraph equation. We show that the diffusion equation, being the correct limit of the DCTRWs, gives better approximations in $L_2$ norm to the DCTRWs than the telegraph equation. We conclude therefore that, first, the DCTRWs do not provide any correct microscopic interpretation of the one-dimensional telegraph equation, and second, the kinetic (exact) model of the telegraph equation is different from the model based on the DCTRWs.Comment: 12 pages, 9 figure

Conditioning an additive functional of a markov chain to stay non-negative. I, Survival for a long time

Let (X-t)(t >= 0) be a continuous-time irreducible Markov chain on a finite state space E, let v be a map v: E -> R \ {0}, and let (phi(t))(t >= 0) be an additive functional defined by phi(t) = integral(0)(t)(X-s) ds. We consider the case in which the process (phi(t))(t >= 0) is oscillating and that in which (phi(t))(t >= 0) has a negative drift. In each of these cases, we condition the process (X-t, phi(t))(t >= 0) on the event that (phi(t))(t >= 0) is nonnegative until time T and prove weak convergence of the conditioned process as T -> infinity