Numerical simulation of the compressible Orszag-Tang vortex 2. Supersonic flow

The numerical investigation of the Orszag-Tang vortex system in compressible magnetofluids will consider initial conditions with embedded supersonic regions. The simulations have initial average Mach numbers 1.0 and 1.5 and beta 10/3 with Lundquist numbers 50, 100, or 200. The behavior of the system differs significantly from that found previously for the incompressible and subsonic analogs. Shocks form at the downstream boundaries of the embedded supersonic regions outside the central magnetic X-point and produce strong local current sheets which dissipate appreciable magnetic energy. Reconnection at the central X-point, which dominates the incompressible and subsonic systems, peaks later and has a smaller impact as M increases from 0.6 to 1.5. Similarly, correlation between the momentum and magnetic field begins significant growth later than in subsonic and incompressible flows. The shocks bound large compression regions, which dominate the wavenumber spectra of autocorrelations in mass density, velocity, and magnetic field

The Phylogenetic position of Daubentonia madagascariensis (Gmelin, 1788; primates, Strepsirhini) as revealed by chromosomal analysis

One of the major topics in primate evolution is the phylogenetic position of the bizarre Daubentonia madagascariensis (DMA, aye-aye). The principal points that have been discussed for many decades are whether the aye-aye is: (i) the sister group of primates; (ii) the sister group of strepsirhines; or (iii) the sister group of lemurs. Very little is known about Daubentonia evolution, particularly on the chromosomal background. The present report focuses on the chromosomal history of this species. We used available chromosome painting data as the main source to identify conserved chromosomes, chromosomal segments and syntenic associations that have characterized the aye-aye karyotype. The dataset includes 47 characters that have been subjected to a concatenated analysis using maximum parsimony (MP) and Bayesian inference (BI). Both MP and BI topologies show Daubentonia as an independent monophyletic lineage, sister group of all other Strepsirhini. Further, both trees have weak statistical support as result of the high number of autapomorphies and homoplasies that have characterized the history of this group of specie

ASSESSING DEER DAMAGE IN YOUNG FRUIT ORCHARDS

Evaluations of systematic damage assessments of 5, 10 and 20 percent of all apple trees in 12 orchards were compared. The 10% assessment technique was selected as the most accurate and efficient in estimating summer and fall damage. Analysis of several parameters of tree vigor found significant differences between browsed and unbrowsed trees for tree basal diameter and central leader diameter over 2 successive years. These subtle yet important differences in tree development were felt to severely limit the possibilities of relating browsing to growth and. later, yields. Methods and considerations for making control decisions on a per acre basis are discussed

The role of initial conditions in the ageing of the long-range spherical model

The kinetics of the long-range spherical model evolving from various initial states is studied. In particular, the large-time auto-correlation and -response functions are obtained, for classes of long-range correlated initial states, and for magnetized initial states. The ageing exponents can depend on certain qualitative features of initial states. We explicitly find the conditions for the system to cross over from ageing classes that depend on initial conditions to those that do not.Comment: 15 pages; corrected some typo

Metabolomics as a Powerful Tool for Molecular Quality Assessment of the Fish Sparus aurata

The molecular profiles of perchloric acid solutions extracted from the flesh of Sparus aurata fish specimens, produced according to different aquaculture systems, have been investigated. The 1H-NMR spectra of aqueous extracts are indicative of differences in the metabolite content of fish reared under different conditions that are already distinguishable at their capture, and substantially maintain the same differences in their molecular profiles after sixteen days of storage under ice. The fish metabolic profiles are studied by top-down chemometric analysis. The results of this exploratory investigation show that the fish metabolome accurately reflects the rearing conditions. The level of many metabolites co-vary with the rearing conditions and a few metabolites are quantified including glycogen (stress indicator), histidine, alanine and glycine which all display significant changes dependent on the aquaculture system and on the storage times

Access and adherence to isoniazid preventive therapy and occurrence of active TB in a cohort of people living with HIV: a retrospective cohort study in Sao Paulo, Brazil

Tuberculosis (TB) is still a leading cause of morbidity and mortality among people living with HIV (PLHIV). The diagnosis of latent TB is required for the implementation of prophylactic therapy with isoniazid (PTI). However, low access to diagnosis of latent TB and non-adherence to PTI may hinder potential benefits of this essential intervention. In this study, we addressed the access and adherence to PTI in a cohort of PLHIV with positive tuberculin skin test (TST) in a reference HIV clinic in Sao Paulo, Brazil. We have also analyzed the occurrence of active TB over a median of 131 months after a positive TST among study participants. Our findings revealed that 88.3% of the 238 TST-positive patients had access to PTI, and 196 (93.3%) of those with access adhered to PTI. Active tuberculosis was diagnosed in three of the 196 TST-positive patients who adhered to PTI (1.5%; 95% confidence interval [CI] 0.3-4.4%), whereas seven cases were detected among 42 patients without access or who did not adhere to PTI (16.6%; 95% CI 7.0-31.3%). The apparent beneficial effect of PTI in our cohort is consistent with previous studies including PLHIV, and highlights the importance of reliably delivering each of the steps between screening for latent TB and provision of PTI

Ageing in the critical contact process: a Monte Carlo study

The long-time dynamics of the critical contact process which is brought suddenly out of an uncorrelated initial state undergoes ageing in close analogy with quenched magnetic systems. In particular, we show through Monte Carlo simulations in one and two dimensions and through mean-field theory that time-translation invariance is broken and that dynamical scaling holds. We find that the autocorrelation and autoresponse exponents lambda_{Gamma} and lambda_R are equal but, in contrast to systems relaxing to equilibrium, the ageing exponents a and b are distinct. A recent proposal to define a non-equilibrium temperature through the short-time limit of the fluctuation-dissipation ratio is therefore not applicable.Comment: 18 pages, 7 figures, Latex2e with IOP macros; final for

Aging at Criticality in Model C Dynamics

We study the off-equilibrium two-point critical response and correlation functions for the relaxational dynamics with a coupling to a conserved density (Model C) of the O(N) vector model. They are determined in an \epsilon=4-d expansion for vanishing momentum. We briefly discuss their scaling behaviors and the associated scaling forms are determined up to first order in epsilon. The corresponding fluctuation-dissipation ratio has a non trivial large time limit in the aging regime and, up to one-loop order, it is the same as that of the Model A for the physically relevant case N=1. The comparison with predictions of local scale invariance is also discussed.Comment: 13 pages, 1 figur

Mitotic Rounding Alters Cell Geometry to Ensure Efficient Bipolar Spindle Formation

Accurate animal cell division requires precise coordination of changes in the structure of the microtubule-based spindle and the actin-based cell cortex. Here, we use a series of perturbation experiments to dissect the relative roles of actin, cortical mechanics, and cell shape in spindle formation. We find that, whereas the actin cortex is largely dispensable for rounding and timely mitotic progression in isolated cells, it is needed to drive rounding to enable unperturbed spindle morphogenesis under conditions of confinement. Using different methods to limit mitotic cell height, we show that a failure to round up causes defects in spindle assembly, pole splitting, and a delay in mitotic progression. These defects can be rescued by increasing microtubule lengths and therefore appear to be a direct consequence of the limited reach of mitotic centrosome-nucleated microtubules. These findings help to explain why most animal cells round up as they enter mitosis