Heat flux scaling in turbulent Rayleigh-B\'enard convection with an imposed longitudinal wind

We present a numerical study of Rayleigh-B\'enard convection disturbed by a longitudinal wind. Our results show that under the action of the wind, the vertical heat flux through the cell initially decreases, due to the mechanism of plumes-sweeping, and then increases again when turbulent forced convection dominates over the buoyancy. As a result, the Nusselt number is a non-monotonic function of the shear Reynolds number. We provide a simple model that captures with good accuracy all the dynamical regimes observed. We expect that our findings can lead the way to a more fundamental understanding of the of the complex interplay between mean-wind and plumes ejection in the Rayleigh-B\'enard phenomenology.Comment: 5 pages, 4 figure

Phosphorylation stoichiometries of human eukaryotic initiation factors.

Eukaryotic translation initiation factors are the principal molecular effectors regulating the process converting nucleic acid to functional protein. Commonly referred to as eIFs (eukaryotic initiation factors), this suite of proteins is comprised of at least 25 individual subunits that function in a coordinated, regulated, manner during mRNA translation. Multiple facets of eIF regulation have yet to be elucidated; however, many of the necessary protein factors are phosphorylated. Herein, we have isolated, identified and quantified phosphosites from eIF2, eIF3, and eIF4G generated from log phase grown HeLa cell lysates. Our investigation is the first study to globally quantify eIF phosphosites and illustrates differences in abundance of phosphorylation between the residues of each factor. Thus, identification of those phosphosites that exhibit either high or low levels of phosphorylation under log phase growing conditions may aid researchers to concentrate their investigative efforts to specific phosphosites that potentially harbor important regulatory mechanisms germane to mRNA translation

On the Timing of the Peak Mean and Variance for the Number of Customers in an M(t)/M(t)/1 Queueing System

Revised October 1994This paper examines the time lag between the peak in the arrival rate and the peaks in the mean and variance for the number of customers in an M(t)/M(t)/1l system. We establish a necessary condition for the time at which the peak in the mean is achieved. In cases in which system utilization exceeds one during some period, we show that the peak in the mean occurs after the end of this period

Dynactin-dependent cortical dynein and spherical spindle shape correlate temporally with meiotic spindle rotation in Caenorhabditis elegans.

Oocyte meiotic spindles orient with one pole juxtaposed to the cortex to facilitate extrusion of chromosomes into polar bodies. In Caenorhabditis elegans, these acentriolar spindles initially orient parallel to the cortex and then rotate to the perpendicular orientation. To understand the mechanism of spindle rotation, we characterized events that correlated temporally with rotation, including shortening of the spindle in the pole-to pole axis, which resulted in a nearly spherical spindle at rotation. By analyzing large spindles of polyploid C. elegans and a related nematode species, we found that spindle rotation initiated at a defined spherical shape rather than at a defined spindle length. In addition, dynein accumulated on the cortex just before rotation, and microtubules grew from the spindle with plus ends outward during rotation. Dynactin depletion prevented accumulation of dynein on the cortex and prevented spindle rotation independently of effects on spindle shape. These results support a cortical pulling model in which spindle shape might facilitate rotation because a sphere can rotate without deforming the adjacent elastic cytoplasm. We also present evidence that activation of spindle rotation is promoted by dephosphorylation of the basic domain of p150 dynactin

Conditions on argument drop

This article pursues the idea that null arguments are derived without any statement or parameter, instead following "naturally" from 3rd factor principles and effects (in the sense of Chomsky 2005). The article thus contributes to the program of eliminating statements in grammar in favor of general factors. More specifically, it develops a theory of C/edge linking in terms of syntactically active but silent C-features, where all referential definite arguments, overt and silent, must match these features in order to be successfully C/edge-linked (interpreted). On the approach pursued, radically silent arguments-such as Germanic zero topics and controlled 3rd person null subjects in Finnish-commonly raise across a lexical C (a complementizer or a verb-second (V2) verb) into the edge of the C-domain for the purpose of successful C/edge linking (circumventing C-intervention), thereby showing (A) over bar -behavior not observed for other types of arguments (including the Romance type of pro). Silent arguments are universally available in syntax, whereas their C/edge linking is constrained by factors (such as Germanic V2) that may or may not be present or active in individual languages and constructions

The split T analysis

This essay pursues The Split T Analysis, claiming that finite clauses have three syntactically active T heads, roughly corresponding to the Reichenbachian S, R, E: Speech Tense, TS, in the C-domain, Referential Tense, TR (or simply T) in the T-domain, and Event Tense, TE, in the v-domain. This analysis, it is argued, enables a coherent account of the relationship between tense morphology (including Tense Agreement) and Tense syntax (including Sequence of Tenses phenomena and Double Access Readings)

The Silence Principle.

Abstract not availabl