73 research outputs found
A Planetary Mass Companion to the K0 Giant HD 17092
We report the discovery of a substellar-mass companion to the K0-giant HD
17092 with the Hobby-Eberly Telescope. In the absence of any correlation of the
observed 360-day periodicity with the standard indicators of stellar activity,
the observed radial velocity variations are most plausibly explained in terms
of a Keplerian motion of a planetary-mass body around the star. With the
estimated stellar mass of 2.3Msun, the minimum mass of the planet is 4.6MJ. The
planet's orbit is characterized by a mild eccentricity of e=0.17 and a
semi-major axis of 1.3 AU. This is the tenth published detection of a planetary
companion around a red giant star. Such discoveries add to our understanding of
planet formation around intermediate-mass stars and they provide dynamical
information on the evolution of planetary systems around post-main sequence
stars.Comment: 13 pages, 3 figures, 2 tables. Submitted to Ap
The First Extrasolar Planet Discovered with a New Generation High Throughput Doppler Instrument
We report the detection of the first extrasolar planet, ET-1 (HD 102195b),
using the Exoplanet Tracker (ET), a new generation Doppler instrument. The
planet orbits HD 102195, a young star with solar metallicity that may be part
of the local association. The planet imparts radial velocity variability to the
star with a semiamplitude of m s and a period of 4.11 days.
The planetary minimum mass () is .Comment: 42 pages, 11 figures and 5 tables, Accepted for publication in Ap
Prime movers : mechanochemistry of mitotic kinesins
Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation
A measurement by BOOMERANG of multiple peaks in the angular power spectrum of the cosmic microwave background
This paper presents a measurement of the angular power spectrum of the Cosmic
Microwave Background from l=75 to l=1025 (~10' to 5 degrees) from a combined
analysis of four 150 GHz channels in the BOOMERANG experiment. The spectrum
contains multiple peaks and minima, as predicted by standard
adiabatic-inflationary models in which the primordial plasma undergoes acoustic
oscillations. These results significantly constrain the values of Omega_tot,
Omega_b h^2, Omega_c h^2 and n_s.Comment: changes to reflect version accepted by Ap
Proteomic analysis of the Plasmodium male gamete reveals the key role for glycolysis in flagellar motility.
BACKGROUND: Gametogenesis and fertilization play crucial roles in malaria transmission. While male gametes are thought to be amongst the simplest eukaryotic cells and are proven targets of transmission blocking immunity, little is known about their molecular organization. For example, the pathway of energy metabolism that power motility, a feature that facilitates gamete encounter and fertilization, is unknown.
METHODS: Plasmodium berghei microgametes were purified and analysed by whole-cell proteomic analysis for the first time. Data are available via ProteomeXchange with identifier PXD001163.
RESULTS: 615 proteins were recovered, they included all male gamete proteins described thus far. Amongst them were the 11 enzymes of the glycolytic pathway. The hexose transporter was localized to the gamete plasma membrane and it was shown that microgamete motility can be suppressed effectively by inhibitors of this transporter and of the glycolytic pathway.
CONCLUSIONS: This study describes the first whole-cell proteomic analysis of the malaria male gamete. It identifies glycolysis as the likely exclusive source of energy for flagellar beat, and provides new insights in original features of Plasmodium flagellar organization
The BOOMERanG experiment and the curvature of the Universe
We describe the BOOMERanG experiment and its main result, i.e. the
measurement of the large scale curvature of the Universe. BOOMERanG is a
balloon-borne microwave telescope with sensitive cryogenic detectors. BOOMERanG
has measured the angular distribution of the Cosmic Microwave Background on
of the sky, with a resolution of arcmin and a sensitivity
of per pixel. The resulting image is dominated by hot and cold
spots with rms fluctuations and typical size of . The
detailed angular power spectrum of the image features three peaks and two dips
at and , respectively. Such very characteristic
spectrum can be explained assuming that the detected structures are the result
of acoustic oscillations in the primeval plasma. In this framework, the
measured pattern constrains the density parameter to be (95% confidence interval). Other cosmological parameters, like the
spectral index of initial density fluctuations, the density parameter for
baryons, dark matter and dark energy, are detected or constrained by the
BOOMERanG measurements and by other recent CMB anisotropy experiments. When
combined with other cosmological observations, these results depict a new,
consistent, cosmological scenario.Comment: Proc. of the Erice School on "Neutrinos in Astro, Particle and
Nuclear Physics", 18.-26. September 2001, Amand Faessler, Jan Kuckei eds,
"Progress in Particle and Nuclear Physics", vol. 4
Association and Haplotype Analyses of Positional Candidate Genes in Five Genomic Regions Linked to Scrotal Hernia in Commercial Pig Lines
Scrotal hernia in pigs is a complex trait likely affected by genetic and environmental factors. A large-scale association analysis of positional and functional candidate genes was conducted in four previously identified genomic regions linked to hernia susceptibility on Sus scrofa chromosomes 2 and 12, as well as the fifth region around 67 cM on chromosome 2, respectively. In total, 151 out of 416 SNPs discovered were genotyped successfully. Using a family-based analysis we found that four regions surrounding ELF5, KIF18A, COL23A1 on chromosome 2, and NPTX1 on chromosome 12, respectively, may contain the genetic variants important for the development of the scrotal hernia in pigs. These findings were replicated in another case-control dataset. The SNPs around the ELF5 region were in high linkage disequilibrium with each other, and a haplotype containing SNPs from ELF5 and CAT was highly significantly associated with hernia development. Extensive re-sequencing work focused on the KIF18A gene did not detect any further SNPs with extensive association signals. These genes may be involved in the estrogen receptor signaling pathway (KIF18A and NPTX1), the epithelial-mesenchymal transition (ELF5) and the collagen metabolism pathway (COL23A1), which are associated with the important molecular characteristics of hernia pathophysiology. Further investigation on the molecular mechanisms of these genes may provide more molecular clues on hernia development in pigs
Fractografia de compósito estrutural aeronáutico submetido à caracterização de tenacidade à fratura interlaminar em modo I
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