CoRoT measures solar-like oscillations and granulation in stars hotter than the Sun     

Michel E  Baglin A  Auvergne M  Catala C  Samadi R  Baudin F  Appourchaux T  Barban C  Weiss WW  Berthomieu G  Boumier P  Dupret MA  Garcia RA  Fridlund M  Garrido R  Goupil MJ  Kjeldsen H  Lebreton Y  Mosser B  Grotsch-Noels A  Janot-Pacheco E  Provost J  Roxburgh IW  Thoul A  Toutain T  Tiphène D  Turck-Chieze S  Vauclair SD  Vauclair GP  Aerts C  Alecian G  Ballot J  Charpinet S  Hubert AM  Lignières F  Mathias P  Monteiro MJ  Neiner C  Poretti E  de Medeiros JR  Ribas I  Rieutord ML  Cortés TR  Zwintz K 《Science (New York, N.Y.)》2008,322(5901):558-560

Oscillations of the Sun have been used to understand its interior structure. The extension of similar studies to more distant stars has raised many difficulties despite the strong efforts of the international community over the past decades. The CoRoT (Convection Rotation and Planetary Transits) satellite, launched in December 2006, has now measured oscillations and the stellar granulation signature in three main sequence stars that are noticeably hotter than the sun. The oscillation amplitudes are about 1.5 times as large as those in the Sun; the stellar granulation is up to three times as high. The stellar amplitudes are about 25% below the theoretic values, providing a measurement of the nonadiabaticity of the process ruling the oscillations in the outer layers of the stars.  相似文献   

Long-range correlations in the diffuse seismic coda   总被引：9，自引：0，他引：9  

Campillo M  Paul A 《Science (New York, N.Y.)》2003,299(5606):547-549

The late seismic coda may contain coherent information about the elastic response of Earth. We computed the correlations of the seismic codas of 101 distant earthquakes recorded at stations that were tens of kilometers apart. By stacking cross-correlation functions of codas, we found a low-frequency coherent part in the diffuse field. The extracted pulses have the polarization characteristics and group velocities expected for Rayleigh and Love waves. The set of cross-correlations has the symmetries of the surface-wave part of the Green tensor. This seismological example shows that diffuse waves produced by distant sources are sufficient to retrieve direct waves between two perfectly located points of observation. Because it relies on general properties of diffuse waves, this result has potential applications in other fields.  相似文献   

Biodiversity science evolves     

Dirzo R  Loreau M 《Science (New York, N.Y.)》2005,310(5750):943

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Infectious behavior in a parasitoid     

Varaldi J  Fouillet P  Ravallec M  López-Ferber M  Boulétreau M  Fleury F 《Science (New York, N.Y.)》2003,302(5652):1930

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Single molecules. Molecular entanglements     

Orrit M 《Science (New York, N.Y.)》2002,298(5592):369-370

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A physical map of the 1-gigabase bread wheat chromosome 3B   总被引：2，自引：0，他引：2  

Paux E  Sourdille P  Salse J  Saintenac C  Choulet F  Leroy P  Korol A  Michalak M  Kianian S  Spielmeyer W  Lagudah E  Somers D  Kilian A  Alaux M  Vautrin S  Bergès H  Eversole K  Appels R  Safar J  Simkova H  Dolezel J  Bernard M  Feuillet C 《Science (New York, N.Y.)》2008,322(5898):101-104

As the staple food for 35% of the world's population, wheat is one of the most important crop species. To date, sequence-based tools to accelerate wheat improvement are lacking. As part of the international effort to sequence the 17-billion-base-pair hexaploid bread wheat genome (2n = 6x = 42 chromosomes), we constructed a bacterial artificial chromosome (BAC)-based integrated physical map of the largest chromosome, 3B, that alone is 995 megabases. A chromosome-specific BAC library was used to assemble 82% of the chromosome into 1036 contigs that were anchored with 1443 molecular markers, providing a major resource for genetic and genomic studies. This physical map establishes a template for the remaining wheat chromosomes and demonstrates the feasibility of constructing physical maps in large, complex, polyploid genomes with a chromosome-based approach.  相似文献   

On the origin of interictal activity in human temporal lobe epilepsy in vitro     

Cohen I  Navarro V  Clemenceau S  Baulac M  Miles R 《Science (New York, N.Y.)》2002,298(5597):1418-1421

The origin and mechanisms of human interictal epileptic discharges remain unclear. Here, we describe a spontaneous, rhythmic activity initiated in the subiculum of slices from patients with temporal lobe epilepsy. Synchronous events were similar to interictal discharges of patient electroencephalograms. They were suppressed by antagonists of either glutamatergic or gamma-aminobutyric acid (GABA)-ergic signaling. The network of neurons discharging during population events comprises both subicular interneurons and a subgroup of pyramidal cells. In these pyramidal cells, GABAergic synaptic events reversed at depolarized potentials. Depolarizing GABAergic responses in neurons downstream to the sclerotic CA1 region contribute to human interictal activity.  相似文献   

Long-term trends in the abundance of Mediterranean wetland vertebrates: From global recovery to localized declines     

Thomas Galewski  Ben Collen  Louise McRae  Jonathan Loh  Patrick Grillas  Michel Gauthier-Clerc  Vincent Devictor 《Biological conservation》2011,(5):1392-1399

Biodiversity loss is unevenly distributed in space and time. Species have reached critically low population sizes in some areas, and remain abundant in others. Similarly, some species may benefit from successful conservation plans, while others still experience severe population depletions driven by negative impacts of human activities. Although several indicators have been proposed to measure the fate of biodiversity, they are generally only implemented globally so their relevance for regional assessment is still unclear. Here, we calculated the first regional trend in the Living Planet Index for the Mediterranean wetlands (Med LPI), an indicator that summarizes the fate of global biological diversity based on the temporal trends in abundance of vertebrate populations. The Med LPI was based on 1641 vertebrate populations of 311 species recorded in Mediterranean wetlands from 1970–2008, in 27 different countries. We investigated whether trends in the Med LPI differed between eastern and western Mediterranean countries, which have different socio-economic contexts. Finally, we assessed whether and how the trend in the Med LPI was robust to changes in the number and identity of species considered. We found that, at the Mediterranean scale, the Med LPI increased steeply, which could be taken at first sight, as a general recovery of wetland biodiversity in this biogeographical region. However, we found highly contrasting spatial trends within the Mediterranean region: the average trend was positive for western and negative for eastern countries. Moreover, we showed that depending on the method used to estimate the trend in Med LPI, it can be sensitive to the number and identity of the species considered. We suggest that understanding the regional discrepancies of the trend in biodiversity indicators as well as their robustness to the species represented in the index will enhance progress assessment towards global and regional conservation strategies.  相似文献   

Properties of chalconaringenin and rutin isolated from cherry tomatoes     

Slimestad R  Verheul M 《Journal of agricultural and food chemistry》2011,59(7):3180-3185

Fresh cherry tomatoes cv. 'Susanne' contain more of the two flavonoids chalconaringenin (CN) and rutin than lycopene. Therefore some properties including antioxidant behavior of the flavonoids were studied. The two flavonoids were extracted from peel and isolated by use of different chromatographic methods. Molecular absorbtivities were found to be 26907 for CN and 20328 abs M(-1) cm(-1) for rutin. Both compounds exhibited properties as antioxidants through several assays, and rutin was found to be the strongest antioxidant except in one assay. None of the assays revealed pro-oxidative effects. As naringenin rather than CN is frequently reported as a tomato constituent, the stability of CN was investigated in order to detect potential ways of isomerization during sample preparation. CN isomerized slowly both under UVB radiation and in alkaline solutions. Thus, such factors do not explain the occurrence of naringenin in tomato samples. The deficiency in reports on CN may be explained by the similarity in chromatographic behaviors of CN and naringenin, and due to the fact that they have same molecular weights.  相似文献   

Comparison of the pig and feline models for full thickness corneal transplantation     

Brunette I  Rosolen SG  Carrier M  Abderrahman M  Nada O  Germain L  Proulx S 《Veterinary ophthalmology》2011,14(6):365-377

Purpose The goal of this study was to report on the advantages and limitations of the pig and feline models for experimental in vivo corneal transplantation. Methods Ten healthy domestic pigs and ten healthy cats were used. Full thickness penetrating keratoplasty was performed using autologous (eight cases), allogeneic (seven cases) or human xenogeneic (three cases) tissue. In two other cases, the inflammatory response to partial thickness trephination (without transplantation) was evaluated. Eyes were assessed daily before and after surgery by slit‐lamp, pachymetry, and tonometry. A transparency score ranging from 0 (opaque graft) to 4 (clear graft) was used, based on the slit‐lamp examination. Optical coherence tomography, histology, and electron microscopy were performed postmortem. Results In the pig, the mean (±SD) transparency score for the eight full thickness grafts was 0.88 ± 0.99, ranging from 0 to 3. In the feline model, the mean transparency score for the seven uncomplicated grafts was 3.93 ± 0.19, ranging from 3.5 to 4. Both negative controls without endothelium remained opaque at all time. Intraoperative tendency for iris incarceration into the wound, rapid corneal swelling, suture cheese wiring, and postoperative intraocular inflammation were the main factors jeopardizing the functional success of the corneal transplant in the pig model. Conclusion Suboptimal functional results were obtained after full thickness corneal transplantation in the pig model, while in the feline model, the same protocol yielded uneventful surgeries and clear transplants, with functional results similar to those achieved in human subjects.  相似文献