Computer studies of baroclinic flow

Programs necessary for computing the transition curve on the regime diagram for the atmospheric general circulation experiment (AGOE) were completed and used to determine the regime diagram for the rotating annulus and some axisymmetric flows for one possible AGOE configuration. The effect of geometrical constraints on the size of eddies developing from a basic state is being examined. In AGOE, the geometric constraint should be the width of the shear zone or the baroclinic zone. Linear and nonlinear models are to be used to examine both barotropic and baroclinic flows. The results should help explain the scale selection mechanism of baroclinic eddies in the atmosphere experimental models such as AGOE, and the multiple vortex phenomenon in tornadoes

the role of shock waves in modulation of galactic cosmic rays

The understanding of modulation of the galactic cosmic rays has considerably progressed by the exploration by space probes of major heliospheric structures, such as the Corotating Interaction Regions, the neutral sheet, and the compression regions of intense heliospheric magnetic fields. Also relevant in this context were the detections in the outer heliosphere of long lasting Forbush type decreases of cosmic ray intensity. The results of recent theoretical studies on the changes in intensity and energy, at different location from the Sun, induced by the passage of shocks across the heliosphere are presented. In this version of the research, the simplest cases of modulation of uGV and 2GV particles by single or several shocks during periods of positive and negative solar field polarity are reviewed. The results of the theoretical aspects of the search is reported. The comparison of the theoretical predictions with space probe data allows conclusions to be drawn on the role of shocks on the modulation on both the 11 and 22 year galactic cosmic ray cycles in the outer heliosphere and on the plausibility of the models and parameters used

The topological structure of scaling limits of large planar maps

We discuss scaling limits of large bipartite planar maps. If p is a fixed integer strictly greater than 1, we consider a random planar map M(n) which is uniformly distributed over the set of all 2p-angulations with n faces. Then, at least along a suitable subsequence, the metric space M(n) equipped with the graph distance rescaled by the factor n to the power -1/4 converges in distribution as n tends to infinity towards a limiting random compact metric space, in the sense of the Gromov-Hausdorff distance. We prove that the topology of the limiting space is uniquely determined independently of p, and that this space can be obtained as the quotient of the Continuum Random Tree for an equivalence relation which is defined from Brownian labels attached to the vertices. We also verify that the Hausdorff dimension of the limit is almost surely equal to 4.Comment: 45 pages Second version with minor modification

Magnesium regulates transcription of the mgtA (magnesium transporter) gene in Salmonella enterica serovar typhimurium via prolyl-bond formation during translation of the mgtL leader ORF

In Enterobacteriaceae, the mgtA gene encodes a P-type ATPase that mediates Mg2+ uptake and is up-regulated by the PhoQP two-component system during invasion of host epithelial cells and macrophages. The regulation of mgtA has recently gained special interest given that it exists at several stages, including transcription, post-transcription and post-translation, in response to Mg2+availability. The mgtA mRNA has a 264-nucleotide 5’ leader that contains a 17 codon, proline-rich ORF, termed mgtL, whose translation has been proposed to affect the folding of the 5’ leader mRNA, which in turn regulates whether transcription is terminated before the mgtA structural gene at high Mg2+ concentrations, or is allowed to read through at limiting Mg2+ concentrations. We hypothesize that Mg2+ directly regulates translation of mgtL by facilitating prolyl-bond formation. We find that rescue of ribosome stalling at proline codons of mgtL by translation factor EF-P and methylation of tRNAPro with m1G37 by TrmD both play roles in the regulation of mgtLtranslation. Of potential significance is that TrmD is dependent on Mg2+ for its tRNA methylation activity, implying an underlying role of Mg 2+ in the regulation. We suggest a complex interaction between Mg 2+, proline, EF-P and TrmD in the regulation of mgtL translation and mgtA transcription. In addition, we provide preliminary results implicating an unknown transcription factor and other potential growth conditions in the regulation of mgtA expression

A provenance and progency test in northern red oak (quercus rubra L.)

Seedlings of forty-nine open-pollinated families of northern red oak (Quercus rubra L.) form six geographic sources were evaluated for total height at two, three and four years from seed; for diameter a foot above ground and total height at six years from seed and for date of bud break and number of flushes at four, five, and six years from seed. The amount of heat required for bud break of northern red oak, as represented by a temperature summation, was not a constant. Total height was not related to latitude of the seed source and is thus probably not controlled by photoperiod. Date of bud break of the seedlings was not associated with latitude and elevation of the seed source and is possibly related to length of frost-free period of the seed source. Seed source selection for date of bud break should prevent frost damage to planted northern red oak seedlings. Seed source, among-family and within-family selection yield predicted gains in juvenile height of 28 to 55 percent in an open-pollinated seed orchard. These gains depend upon the inclusion of a single outstanding seed source in the test. Such gains should ameliorate the problem of poor juvenile height growth in planted northern red oak. Heritability estimates for total height six years from seed range from .20 to .37

Spanwise loading distribution and wake velocity surveys of a semi-span wing

The spanwise distribution of bound circulation on a semi-span wing and the flow velocities in its wake were measured in a wind tunnel. Particular attention was given to documenting the flow velocities in and around the development tip vortex. A two-component laser velocimeter was used to make the velocity measurements. The spanwise distribution of bound circulation, three components of the time-averaged velocities throughout the near wake their standard deviations, and the integrated forces and moments on a metric tip as measured by an internal strain gage balance are presented without discussion

The role of unions in addressing behavioural market failures

The traditional view of economists is that unions cause market failures, thereby reducing economic efficiency. Freeman and Medoff challenged this overly negative view, suggesting unions address market failures associated with the ‘public goods’ aspects of terms and conditions in the workplace for members and non-members alike. This paper builds upon their work by arguing workers’ collective voice via unions can also be used to address particular behavioural market failures associated with common defects in individual cognition. Specifically, this paper suggests how unions through membership, expert and organisational learning effects can help address four common behavioural market failures or cognitive mistakes, namely, short-termism, inattention to important but hidden attributes, unrealistic optimism, and poor probability estimation. In order to explore how the three effects help mitigate the four failures, the paper draws upon insights from behavioural economics. Finally, the paper discusses the factors which influence the extent of the application of the three effects

Applying the expanding photosphere and standardized candle methods to Type II-Plateau supernovae at cosmologically significant redshifts: the distance to SN 2013eq

Based on optical imaging and spectroscopy of the Type II-Plateau SN 2013eq, we present a comparative study of commonly used distance determination methods based on Type II supernovae. The occurrence of SN 2013eq in the Hubble flow (z = 0.041 +/- 0.001) prompted us to investigate the implications of the difference between "angular" and "luminosity" distances within the framework of the expanding photosphere method (EPM) that relies upon a relation between flux and angular size to yield a distance. Following a re-derivation of the basic equations of the EPM for SNe at non-negligible redshifts, we conclude that the EPM results in an angular distance. The observed flux should be converted into the SN rest frame and the angular size, theta, has to be corrected by a factor of (1+z)^2. Alternatively, the EPM angular distance can be converted to a luminosity distance by implementing a modification of the angular size. For SN 2013eq, we find EPM luminosity distances of D_L = 151 +/- 18 Mpc and D_L = 164 +/- 20 Mpc by making use of different sets of dilution factors taken from the literature. Application of the standardized candle method for Type II-P SNe results in an independent luminosity distance estimate (D_L = 168 +/- 16 Mpc) that is consistent with the EPM estimate.Comment: 12 pages, 4 figures, accepted by A&