836 research outputs found
Strontium ranelate improves bone strength in ovariectomized rat by positively influencing bone resistance determinants
Summary: Treatment of adult ovariectomized (OVX) rats with strontium ranelate prevented vertebral biomechanics degradation as a result of the prevention of bone loss and micro-architecture deterioration associated to an effect on intrinsic bone material quality. Strontium ranelate influenced the determinants of bone strength by prevention of ovariectomy-induced changes which contribute to explain strontium ranelate antifracture efficacy. Introduction: Strontium ranelate effects on the determinants of bone strength in OVX rats were evaluated. Methods: Adult female Sprague-Dawley rats were OVX, then treated daily for 52weeks with 125, 250, or 625mg strontium ranelate/kg. Bone strength, mass, micro-architecture, turnover, and intrinsic quality were assessed. Results: Strontium ranelate prevented ovariectomy-induced deterioration in mechanical properties with energy necessary for fracture completely maintained vs. SHAM at 625mg/kg/day, which corresponds to the clinical dose. This was related to a dose-dependent effect on bone volume, higher trabeculae number, and lower trabecular separation in strontium ranelate vs. OVX. Load and energy required to induce lamella deformation were higher with strontium ranelate than in OVX and in SHAM, indicating that the bone formed with strontium ranelate is able to withstand greater damage before fracture. Bone formation was maintained high or even increased in strontium ranelate as shown by mineralizing surfaces and alkaline phosphatase while strontium ranelate led to reductions in deoxypyridinoline. Conclusion: Strontium ranelate administered at 625mg/kg/day for 52weeks prevented OVX-induced biomechanical properties deterioration by influencing the determinants of bone strength: it prevented bone loss and micro-architecture degradation in association with an effect on intrinsic bone quality. These beneficial effects on bone contribute to explain strontium ranelate antifracture efficac
Microstructure of the Local Interstellar Cloud and the Identification of the Hyades Cloud
We analyze high-resolution UV spectra of the Mg II h and k lines for 18
members of the Hyades Cluster to study inhomogeneity along these proximate
lines of sight. The observations were taken by the Space Telescope Imaging
Spectrograph (STIS) instrument on board the Hubble Space Telescope (HST). Three
distinct velocity components are observed. All 18 lines of sight show
absorption by the Local Interstellar Cloud (LIC), ten stars show absorption by
an additional cloud, which we name the Hyades Cloud, and one star exhibits a
third absorption component. The LIC absorption is observed at a lower radial
velocity than predicted by the LIC velocity vector derived by Lallement &
Bertin (1992) and Lallement et al. (1995), (v(predicted LIC) - v(observed LIC)
= 2.9 +/- 0.7 km/s), which may indicate a compression or deceleration at the
leading edge of the LIC. We propose an extention of the Hyades Cloud boundary
based on previous HST observations of other stars in the general vicinity of
the Hyades, as well as ground-based Ca II observations. We present our fits of
the interstellar parameters for each absorption component. The availability of
18 similar lines of sight provides an excellent opportunity to study the
inhomogeneity of the warm, partially ionized local interstellar medium (LISM).
We find that these structures are roughly homogeneous. The measured Mg II
column densities do not vary by more than a factor of 2 for angular separations
of < 8 degrees, which at the outer edge of the LIC correspond to physical
separations of < 0.6 pc.Comment: 35 pages, 11 figures, AASTEX v.5.0 plus EPSF extensions in mkfig.sty;
accepted by Ap
Kaposi's sarcoma-associated herpesvirus oncoprotein K13 protects against B cell receptor induced growth arrest and apoptosis through NF-ÎșB activation
Kaposi's sarcoma-associated herpesvirus (KSHV) has been linked to the development of Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease (MCD). We have characterized the role of KSHV-encoded viral FLICE inhibitory protein K13 in the modulation of anti-IgM induced growth arrest and apoptosis in B cells. We demonstrate that K13 protects WEHI 231, an immature B cell line, against anti-IgM induced growth arrest and apoptosis. The protective effect of K13 was associated with the activation of the NF-ÎșB pathway and was deficient in its mutant, K13-58AAA, and a structural homolog, vFLIP E8, which lack NF-ÎșB activity. K13 upregulated the expression of NF-ÎșB subunit RelB and blocked the anti-IgM induced decline in c-Myc and rise in p27(Kip1) that have been associated with growth arrest and apoptosis. K13 also upregulated the expression of Mcl-1, an anti-apoptotic member of the Bcl2 family. Finally, K13 protected the mature B cell line Ramos against anti-IgM induced apoptosis through NF-ÎșB activation. Inhibition of anti-IgM induced apoptosis by K13 may contribute to the development of KSHV-associated lymphoproliferative disorders
Parallax of PSR J1744-1134 and the Local Interstellar Medium
We present the annual trigonometric parallax of PSR J1744-1134 derived from
an analysis of pulse times of arrival. The measured parallax, pi = 2.8+/-0.3
mas ranks among the most precisely determined distances to any pulsar. The
parallax distance of 357+/-39 pc is over twice that derived from the dispersion
measure using the Taylor & Cordes model for the Galactic electron distribution.
The mean electron density in the path to the pulsar, n_e = (0.0088 +/- 0.0009)
cm^{-3}, is the lowest for any disk pulsar. We have compared the n_e for PSR
J1744-1134 with those for another 11 nearby pulsars with independent distance
estimates. We conclude that there is a striking asymmetry in the distribution
of electrons in the local interstellar medium. The electron column densities
for pulsars in the third Galactic quadrant are found to be systematically
higher than for those in the first. The former correlate with the position of
the well known local HI cavity in quadrant three. The excess electrons within
the cavity may be in the form of HII clouds marking a region of interaction
between the local hot bubble and a nearby superbubble.Comment: revised version accepted for publication in ApJ Letters; reanalysis
of uncertainty in parallax measure and changes to fig
Wide-field CCD imaging at CFHT: the MOCAM example
We describe a new 4096x4096 pixel CCD mosaic camera (MOCAM) available at the
prime focus of the Canada-France-Hawaii Telescope (CFHT). The camera is a
mosaic of four 2048x2048\mu$m
pixels, providing a field of view of 14'x14' at a scale of 0.21''/pixel. MOCAM
is equipped with B, V, R and I filters and has demonstrated image quality of
0.5''-0.6'' FWHM over the entire field. MOCAM will also be used with the CFHT
adaptive optic bonnette and will provide a field of view of 90'' at a scale of
0.02 ''/pixel. MOCAM works within the CFHT Pegasus software environment and
observers familiar with this system require no additional training to use this
camera effectively. The technical details, the performance and the first images
obtained on the telescope with MOCAM are presented. In particular, we discuss
some important improvements with respect to the standard single-CCD FOCAM
camera, such as multi-output parallel readout and dynamic anti-blooming. We
also discuss critical technical issues concerning future wide-field imaging
facilities at the CFHT prime focus in light of our experience with MOCAM and
our recent experience with the even larger UH 8192x8192 pixel CCD mosaic
camera.Comment: Accepted for publication in Publication of the Astronomical Society
of the Pacific. Latex with aas2pp4.sty and epsf.sty. 12 pages, 10 figure
RĂŽle et place du riz pluvial dans les exploitations du lac Alaotra
International audienceLa rĂ©gion de l'Alaotra repose sur un plateau situĂ© Ă 750 mĂštres d'altitude avec au cĆur de la plaine le lac Alaotra. La surface cultivĂ©e en riziculture est estimĂ©e Ă 148 500 ha en 2000 (FAO/UPDR, 2000), dont 75-80 000 ha dans la cuvette du Lac et plus de 65-70 000 ha au sud et dans les zones en pĂ©riphĂ©rie, qui constitue 10% de la surface rizicole nationale pour seulement 4% des riziculteurs malgaches. Cette rĂ©gion rĂ©alise 33% de la valeur ajoutĂ©e de l'ensemble de la filiĂšre nationale et 15% de la richesse gĂ©nĂ©rĂ©e par le secteur riz. Le climat irrĂ©gulier constitue une contrainte majeure pour tous les agriculteurs du lac Alaotra. Les relations agriculture-Ă©levage sont au cĆur de la problĂ©matique de dĂ©veloppement et d'Ă©volution des exploitations agricoles.Ainsi, avec la saturation des riziĂšres irrigables ou Ă Mauvaise MaĂźtrise de l'Eau (RMME), la colonisation agricole des tanety anciennement dĂ©volus aux pĂąturages extensifs depuis les annĂ©es 1980 s'est accĂ©lĂ©rer, induisant la perturbation des activitĂ©s d'Ă©levage bovin traditionnel extensif Ă objectif de capitalisation qui Ă©voluent aujourd'hui vers un Ă©levage productif (embouche et production laitiĂšre) ou de trait. Le diagnostic rĂ©alisĂ© en 2007 a mis en Ă©vidence 7 types d'exploitations agricoles diffĂ©rents. Les diffĂ©rents systĂšmes de riziculture pluviale se retrouvent sur les plateaux sommitaux et les pentes des collines (en rotation jachĂšre culture sur les sols trĂšs pauvres), les bas de pente et les baiboho, en rotation avec d'autres cultures pluviales (maĂŻs, manioc, pois de terre...) avec ou sans jachĂšre, ou en systĂšme SCV depuis leur introduction au dĂ©but des annĂ©es 2000. L'introduction de variĂ©tĂ©s composites poly-aptitudes de type Sebota a pu lever une contrainte majeure des zones ni totalement irriguĂ©es ni totalement pluviales mais intermĂ©diaires dans les RMME (riziculture pluviale partiellement irriguĂ©e, selon l'accĂšs Ă l'eau et les caractĂ©ristiques climatiques de la saison), Les systĂšmes SCV mis au point sur baiboho avec des successions culturales de type riz de saison / haricot de contre saison - maĂŻs de saison ou riz de saison puis vesce de contre saison associĂ©e ou non Ă des cultures maraĂźchĂšres montrent Ă©galement un niveau de production et de sĂ©curitĂ© par rapport aux alĂ©as climatiques trĂšs proche voire supĂ©rieurs Ă ceux obtenus en riziculture irriguĂ©e. La part du riz pluvial dans la formation du revenu et la sĂ©curitĂ© alimentaire a Ă©tĂ© analysĂ©e pour chaque type d'exploitation et varie de 20 Ă 30 % du revenu riz total (avant autoconsommation), et se rĂ©vĂšle croissante en fonction du rapport tanety / riziĂšre dans l'exploitation. Ainsi, sur certaines zones, le riz pluvial semble avoir de beaux jours devant lui. Mots clĂ©s : Riz pluvial, exploitation agricoles, lac Alaotra, SCV, riz poly-aptitudes
The political economy of the Jospin government
This article explores the political economy of the French Socialist Party (PS), beginning with the neo-liberal U-turn of 1983. It then charts the re-evaluation of the PS's political economic foundations after the 1993 defeat, the rejection of the neo-liberal 'pensée unique', and the rehabilitation of a broadly Keynesian frame of reference. The article goes on to explore how this shift has fed through into the Jospin government's policy and positions at both the national and international level. It explores aspirations to reinvent the EU as a Keynesian social democratic 'policy space', and at the national level, employment, macroeconomic, and structural policies
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