The spin vector of Venus determined from Magellan data

A control network of the north polar region of Venus has been established by selecting and measuring control points on full-resolution radar strips. The measurements were incorporated into a least-squares adjustment program that improved initial estimates of the coordinates of the control points, pole direction, and rotation rate of Venus. The current dataset contains 4206 measurements of 606 points on 619 radar strips. The accuracy of the determination is driven by spacecraft ephemeris errors. An accurate estimate of the rotation period of Venus was obtained by applying an ephemeris improvement technique. The second cycle closure orbits improved ephemeris solutions for 40 orbits (376-384, 520-528, 588-592, 658-668, 1002-1010, 1408-1412, 1746-1764, and 2166-2170) are included and fixed in the geodetic control computations, thus trying the network to the J2000 coordinate system

Inversion of droplet aerosol analyzer data for long-term aerosol–cloud interaction measurements

The droplet aerosol analyzer (DAA) was developed to study the influence of aerosol properties on clouds. It measures the ambient particle size of individual droplets and interstitial particles, the size of the dry (residual) particles after the evaporation of water vapor and the number concentration of the dry (residual) particles. A method was developed for the evaluation of DAA data to obtain the three-parameter data set: ambient particle diameter, dry (residual) particle diameter and number concentration. First results from in-cloud measurements performed on the summit of Mt. Brocken in Germany are presented. Various aspects of the cloud–aerosol data set are presented, such as the number concentration of interstitial particles and cloud droplets, the dry residue particle size distribution, droplet size distributions, scavenging ratios due to cloud droplet formation and size-dependent solute concentrations. This data set makes it possible to study clouds and the influence of the aerosol population on clouds

Evidence of two viscous relaxation processes in the collective dynamics of liquid lithium

New inelastic X-ray scattering experiments have been performed on liquid lithium in a wide wavevector range. With respect to the previous measurements, the instrumental resolution, improved up to 1.5 meV, allows to accurately investigate the dynamical processes determining the observed shape of the the dynamic structure factor, $S(Q,\omega)$. A detailed analysis of the lineshapes shows the co-existence of relaxation processes with both a slow and a fast characteristic timescales, and therefore that pictures of the relaxation mechanisms based on a simple viscoelastic model must be abandoned.Comment: 5 pages, 4 .PS figure

Ranger VII Flight Path and Its Determination from Tracking Data

Flight path and tracking study of Ranger VII LUNAR prob

Evidence of short time dynamical correlations in simple liquids

We report a molecular dynamics (MD) study of the collective dynamics of a simple monatomic liquid -interacting through a two body potential that mimics that of lithium- across the liquid-glass transition. In the glassy phase we find evidences of a fast relaxation process similar to that recently found in Lennard-Jones glasses. The origin of this process is ascribed to the topological disorder, i.e. to the dephasing of the different momentum $Q$ Fourier components of the actual normal modes of vibration of the disordered structure. More important, we find that the fast relaxation persists in the liquid phase with almost no temperature dependence of its characteristic parameters (strength and relaxation time). We conclude, therefore, that in the liquid phase well above the melting point, at variance with the usual assumption of {\it un-correlated} binary collisions, the short time particles motion is strongly {\it correlated} and can be described via a normal mode expansion of the atomic dynamics.Comment: 7 pages, 7 .eps figs. To appear in Phys. Rev.

Inelastic X-ray scattering study of the collective dynamics in liquid sodium

Inelastic X-ray scattering data have been collected for liquid sodium at T=390 K, i.e. slightly above the melting point. Owing to the very high instrumental resolution, pushed up to 1.5 meV, it has been possible to determine accurately the dynamic structure factor, $S(Q,\omega)$, in a wide wavevector range, $1.5 \div 15$ nm$^{-1}$, and to investigate on the dynamical processes underlying the collective dynamics. A detailed analysis of the lineshape of $S(Q,\omega)$, similarly to other liquid metals, reveals the co-existence of two different relaxation processes with slow and fast characteristic timescales respectively. The present data lead to the conclusion that: i) the picture of the relaxation mechanism based on a simple viscoelastic model fails; ii) although the comparison with other liquid metals reveals similar behavior, the data do not exhibit an exact scaling law as the principle of corresponding state would predict.Comment: RevTex, 7 pages, 6 eps figures. Accepted by Phys. Rev.

Numerical simulation of the fracture process in ceramic FPD frameworks caused by oblique loading

Using a newly developed three-dimensional (3D) numerical modeling code, an analysis was performed of the fracture behavior in a three-unit ceramic-based fixed partial denture (FPD) framework subjected to oblique loading. All the materials in the study were treated heterogeneously; Weibull's distribution law was applied to the description of the heterogeneity. The Mohr-Coulomb failure criterion with tensile strength cut-off was utilized in judging whether the material was in an elastic or failed state. The simulated loading area was placed either on the buccal or the lingual cusp of a premolar-shaped pantie with the loading direction at 30 degrees, 45 degrees, 60 degrees, 75 degrees or 90 degrees angles to the occlusal surface. The stress distribution, fracture initiation and propagation in the framework during the loading and fracture process were analyzed. This numerical simulation allowed the cause of the framework fracture to be identified as tensile stress failure. The decisive fracture was initiated in the gingival embrasure of the pontic, regardless of whether the buccal or lingual cusp of the pontic was loaded. The stress distribution and fracture propagation process of the framework could be followed step by step from beginning to end. The bearing capacity and the rigidity of the framework vary with the loading position and direction. The framework loaded with 90 towards the occlusal surface has the highest bearing capacity and the greatest rigidity. The framework loaded with 30 towards the occlusal surface has the least rigidity indicating that oblique loading has a major impact on the fracture of ceramic frameworks. (C) 2015 Elsevier Ltd. All rights reserved

Stage progression and neurological symptoms in Trypanosoma brucei rhodesiense sleeping sickness: role of the CNS inflammatory response

Background: Human African trypanosomiasis progresses from an early (hemolymphatic) stage, through CNS invasion to the late (meningoencephalitic) stage. In experimental infections disease progression is associated with neuroinflammatory responses and neurological symptoms, but this concept requires evaluation in African trypanosomiasis patients, where correct diagnosis of the disease stage is of critical therapeutic importance. Methodology/Principal Findings: This was a retrospective study on a cohort of 115 T.b.rhodesiense HAT patients recruited in Eastern Uganda. Paired plasma and CSF samples allowed the measurement of peripheral and CNS immunoglobulin and of CSF cytokine synthesis. Cytokine and immunoglobulin expression were evaluated in relation to disease duration, stage progression and neurological symptoms. Neurological symptoms were not related to stage progression (with the exception of moderate coma). Increases in CNS immunoglobulin, IL-10 and TNF-α synthesis were associated with stage progression and were mirrored by a reduction in TGF-β levels in the CSF. There were no significant associations between CNS immunoglobulin and cytokine production and neurological signs of disease with the exception of moderate coma cases. Within the study group we identified diagnostically early stage cases with no CSF pleocytosis but intrathecal immunoglobulin synthesis and diagnostically late stage cases with marginal CSF pleocytosis and no detectable trypanosomes in the CSF. Conclusions: Our results demonstrate that there is not a direct linkage between stage progression, neurological signs of infection and neuroinflammatory responses in rhodesiense HAT. Neurological signs are observed in both early and late stages, and while intrathecal immunoglobulin synthesis is associated with neurological signs, these are also observed in cases lacking a CNS inflammatory response. While there is an increase in inflammatory cytokine production with stage progression, this is paralleled by increases in CSF IL-10. As stage diagnostics, the CSF immunoglobulins and cytokines studied do not have sufficient sensitivity to be of clinical value

Estrogen inhibits GH signaling by suppressing GH-induced JAK2 phosphorylation, an effect mediated by SOCS-2

Oral estrogen administration attenuates the metabolic action of growth hormone (GH) in humans. To investigate the mechanism involved, we studied the effects of estrogen on GH signaling through Janus kinase (JAK)2 and the signal transducers and activators of transcription (STATs) in HEK293 cells stably expressing the GH receptor (293GHR), HuH7 (hepatoma) and T-47D (breast cancer) cells. 293GHR cells were transiently transfected with an estrogen receptor-α expression plasmid and luciferase reporters with binding elements for STAT3 and STAT5 or the β-casein promoter. GH stimulated the reporter activities by four- to sixfold. Cotreatment with 17β-estradiol (E2) resulted in a dose-dependent reduction in the response of all three reporters to GH to a maximum of 49-66% of control at 100 nM (P < 0.05). No reduction was seen when E2 was added 1-2 h after GH treatment. Similar inhibitory effects were observed in HuH7 and T-47D cells. E2 suppressed GH-induced JAK2 phosphorylation, an effect attenuated by actinomycin D, suggesting a requirement for gene expression. Next, we investigated the role of the suppressors of cytokine signaling (SOCS) in E2 inhibition. E2 increased the mRNA abundance of SOCS-2 but not SOCS-1 and SOCS-3 in HEK293 cells. The inhibitory effect of E2 was absent in cells lacking SOCS-2 but not in those lacking SOCS-1 and SOCS-3. In conclusion, estrogen inhibits GH signaling, an action mediated by SOCS-2. This paper provides evidence for regulatory interaction between a sex steroid and the GH/JAK/STAT pathway, in which SOCS-2 plays a central mechanistic role