Echoguided closed commissurotomy for mitral valve stenosis in a dog     

Emilie Trehiou-Sechi DVM  Luc Behr DVM  PhD  Valérie Chetboul DVM  PhD  Jean-Louis Pouchelon DVM  PhD  Maud Castaignet DVM  Vassiliki Gouni DVM  Charlotte Misbach DVM  Amandine M.P. Petit DVM  Nicolas Borenstein DVM  PhD 《Journal of Veterinary Cardiology》2011,13(3):219-225

Surgical treatment of mitral stenosis (MS) usually consists of open mitral commissurotomy (MC) or percutaneous balloon MC, which require a cardiopulmonary bypass or transseptal approach, respectively. We describe here the first surgical management of congenital MS in a dog using a less invasive procedure, a surgical closed MC under direct echo guidance. A 5-year-old female Cairn terrier was referred for ascites, weakness, and marked exercise intolerance for 2 months, which was refractory to medical treatment. Diagnosis of severe MS associated with atrial fibrillation (AF) was confirmed by echo-Doppler examination and electrocardiography. Poor response to medical treatment suggested a corrective procedure on the valve was indicated. However, due to the cost and high mortality rate associated with cardiopulmonary bypass, a hybrid MC was recommended. A standard left intercostal thoracotomy was performed and three balloon valvuloplasty catheters of differing diameters were sequentially inserted through the left atrium under direct echo guidance. Transesophageal echocardiography revealed a 62% reduction in the pressure half-time compared to the pre-procedure. Thirteen months after surgery the dog is still doing well with resolution of ascites and a marked improvement of most echo-Doppler variables.  相似文献   

Crystalline Ropes of Metallic Carbon Nanotubes   总被引：7，自引：0，他引：7  

A Thess  R Lee  P Nikolaev  H Dai  P Petit  J Robert  C Xu  YH Lee  SG Kim  AG Rinzler  DT Colbert  GE Scuseria  D Tomanek  JE Fischer  RE Smalley 《Science (New York, N.Y.)》1996,273(5274):483-487

Fullerene single-wall nanotubes (SWNTs) were produced in yields of more than 70 percent by condensation of a laser-vaporized carbon-nickel-cobalt mixture at 1200degreesC. X-ray diffraction and electron microscopy showed that these SWNTs are nearly uniform in diameter and that they self-organize into "ropes," which consist of 100 to 500 SWNTs in a two-dimensional triangular lattice with a lattice constant of 17 angstroms. The x-ray form factor is consistent with that of uniformly charged cylinders 13.8 +/- 0.2 angstroms in diameter. The ropes were metallic, with a single-rope resistivity of <10(-4) ohm-centimeters at 300 kelvin. The uniformity of SWNT diameter is attributed to the efficient annealing of an initial fullerene tubelet kept open by a few metal atoms; the optimum diameter is determined by competition between the strain energy of curvature of the graphene sheet and the dangling-bond energy of the open edge, where growth occurs. These factors strongly favor the metallic (10,10) tube with C5v symmetry and an open edge stabilized by triple bonds.  相似文献   

Overview of VEGA Venus Balloon in Situ Meteorological Measurements     

Sagdeev RZ  Linkin VM  Kerzhanovich VV  Lipatov AN  Shurupov AA  Blamont JE  Crisp D  Ingersoll AP  Elson LS  Preston RA  Hildebrand CE  Ragent B  Seiff A  Young RE  Petit G  Boloh L  Alexandrov YN  Armand NA  Bakitko RV  Selivanov AS 《Science (New York, N.Y.)》1986,231(4744):1411-1414

The VEGA balloons made in situ measurements of pressure, temperature, vertical wind velocity, ambient light, frequency of lightning, and cloud particle backscatter. Both balloons encountered highly variable atmospheric conditions, with periods of intense vertical winds occurring sporadically throughout their flights. Downward winds as large as 3.5 meters per second occasionally forced the balloons to descend as much as 2.5 kilometers below their equilibrium float altitudes. Large variations, in pressure, temperature, ambient light level, and cloud particle backscatter (VEGA-1 only) correlated well during these excursions, indicating that these properties were strong functions of altitude in those parts of the middle cloud layer sampled by the balloons.  相似文献   

Glacial refugia: hotspots but not melting pots of genetic diversity     

Petit R  Aguinagalde I  de Beaulieu JL  Bittkau C  Brewer S  Cheddadi R  Ennos R  Fineschi S  Grivet D  Lascoux M  Mohanty A  Müller-Starck G  Demesure-Musch B  Palmé A  Martín JP  Rendell S  Vendramin GG 《Science (New York, N.Y.)》2003,300(5625):1563-1565

Glacial refuge areas are expected to harbor a large fraction of the intraspecific biodiversity of the temperate biota. To test this hypothesis, we studied chloroplast DNA variation in 22 widespread European trees and shrubs sampled in the same forests. Most species had genetically divergent populations in Mediterranean regions, especially those with low seed dispersal abilities. However, the genetically most diverse populations were not located in the south but at intermediate latitudes, a likely consequence of the admixture of divergent lineages colonizing the continent from separate refugia.  相似文献   

The effects of dietary omega fatty acids on pregnancy rate,plasma prostaglandin metabolite levels,serum progesterone levels,and milk fatty-acid profile in beef cows     

Gavin F. Richardson  Mary A. McNiven  Hélène V. Petit  John L. Duynisveld 《Canadian journal of veterinary research》2013,77(4):314-318

The objectives were to determine the effects of feeding supplements rich in omega-6 or omega-3 fatty acids (FA) during the late gestation to the early postpartum and breeding periods on reproduction and milk FA profile in beef cows. For each of two years, at the beginning of period 1 (mid-December), 72 beef cows, calving in January or February, were assigned to diets supplemented with roasted flaxseed (Flax) or roasted soybean (Soybean). For each of two years, after 11 wk (end of period 1), 18 cows of 36 in the Flax group were switched to the soybean supplement and 18 cows of 36 in the Soybean group were switched to the flax supplement (start of Period 2). Cows were bred by timed artificial insemination (TAI) in week 5 of period 2. The FA composition of the milk reflected the FA profile of the oilseed supplements. There were no differences in pregnancy rates among the 4 groups. The treatments had no effect on plasma prostaglandin metabolite levels or ratios at 4 to 11 d postpartum. At 5 to 6 d post- TAI, pregnant cows fed Flax in period 1 had lower (P < 0.05) plasma prostaglandin F metabolite (PGFM) levels and PGFM to prostaglandin E metabolite (PGEM) ratio than cows fed Soybean, but there were no significant differences at 19 to 20 d post-TAI. Cows pregnant from TAI and fed Flax in period 2 had higher (P < 0.05) serum progesterone levels at 5 to 6 d post-TAI than cows fed Soybean, but there was no difference at 19 to 20 d post-TAI. The dietary treatments had no effect on pregnancy rates, but there were some effects on plasma PGFM levels, PGFM to PGEM ratios, and serum progesterone levels. The FA supplements influenced the FA composition of milk.  相似文献   

A web‐based decision support system to enhance IPM programs in Washington tree fruit     

Vincent P Jones  Jay F Brunner  Gary G Grove  Brad Petit  Gerald V Tangren  Wendy E Jones 《Pest management science》2010,66(6):587-595

BACKGROUND: Integrated pest management (IPM) decision‐making has become more information intensive in Washington State tree crops in response to changes in pesticide availability, the development of new control tactics (such as mating disruption) and the development of new information on pest and natural enemy biology. The time‐sensitive nature of the information means that growers must have constant access to a single source of verified information to guide management decisions. RESULTS: The authors developed a decision support system for Washington tree fruit growers that integrates environmental data [140 Washington State University (WSU) stations plus weather forecasts from NOAA], model predictions (ten insects, four diseases and a horticultural model), management recommendations triggered by model status and a pesticide database that provides information on non‐target impacts on other pests and natural enemies. A user survey in 2008 found that the user base was providing recommendations for most of the orchards and acreage in the state, and that users estimated the value at $ 16 million per year. CONCLUSIONS: The design of the system facilitates education on a range of time‐sensitive topics and will make it possible easily to incorporate other models, new management recommendations or information from new sensors as they are developed. Copyright © 2010 Society of Chemical Industry  相似文献   

AN EMPIRICAL TYPOLOGY OF BRACKISH-WATER POND AQUACULTURE SYSTEMS IN THE PHILIPPINES: A TOOL TO AID COMPARATIVE STUDY IN THE SECTOR     

James R. Stevenson  Xavier T. Irz  Rose-Glenda Alcalde  Pierre Morrisens  Jean Petit 《Aquaculture Economics & Management (Blackwell Science)》2013,17(2):171-193

Aquaculture in the Philippines is long-established but has witnessed rapid technical change in the last 20 years with the introduction of hatchery technology and commercial feed mills changing the production possibilities for a fishpond operator. To understand the sector, a typology of brackish-water pond farming systems is constructed using multivariate methods (principal components analysis, cluster analysis). Eight input variables across all major factors of production are used in the analysis, gathered from a net sample of 136 farms in two regions in 2003. Three latent variables are described, accounting for 58% of variance in the original data: specialization; land vs. labor intensity; and feeding intensity. Five clusters (farm types) are subsequently described: extensive polyculture (40% of sample); semi-intensive prawn-oriented polyculture (11%); low-input labor-intensive farms (27%); very large, extensive milkfish-oriented farms (8%); and semi-intensive milkfish monoculture farms (14%). Implications for technical efficiency estimation and comparative study of economic indicators are discussed.  相似文献   

Soil degradation caused by a high-intensity rainfall event: Implications for medium-term soil sustainability in Burgundian vineyards     

Amélie Quiquerez  Jérôme Brenot  Jean-Pierre Garcia  Christophe Petit 《CATENA》2008

The purpose of this paper is to provide a sediment-flux quantification in a vineyard context (Vosne-Romanée, Burgundy, France) where medium-term soil budget and sustainability are controlled by complex interactions between natural processes (rill erosion) and anthropogenic processes (earth supply transferred back into the rills by the winegrowers).  相似文献   

Characterization of a Mediterranean litter by ¹³C CPMAS NMR: relationships between litter depth, enzyme activities and temperature     

E. Alarcón-Gutiérrez  C. Floch    F. Ziarelli    R. Albrecht    J. Le Petit  C. Augur  & S. Criquet 《European Journal of Soil Science》2008,59(3):486-495

Organic matter mineralization of forest litter is catalysed by the action of different extracellular enzymes produced by microorganisms. Coupling enzyme activities with data on the general macromolecular structure of organic matter, provided by cross‐polarization magic angle spinning ¹³C nuclear magnetic resonance (¹³C CPMAS NMR), allows researchers new insights into organic matter degradation processes. In this paper, the effect of the temperature of incubation on the degradation processes was evaluated in three distinct layers (OhLn, OhLv and OhLf) of an evergreen oak litter (Quercus ilex L.), located in the Mediterranean area of south‐eastern France. We studied degradation phenomena by a combination of ¹³C CPMAS NMR and microbiological analysis. In order to determine the microbial activity of litter layers, three enzyme activities (laccase, cellulase and butyrate esterase) were measured in a 6‐month mesocosm study. Results showed an increase in the alkyl C to O‐alkyl‐C ratio and an increase of the phenolic C and carboxyl C regions, indicating a preferential degradation of polysaccharides. The aromaticity also increased with litter depth and degradation, and humification processes were more elevated at 30°C. anova showed significant effects (P < 0.001) of increased temperature, depth and time of degradation on microbiological variables. Further information is needed about the variations in temperature and temperature‐litter response and soil functions to link fundamental understanding of carbon stabilization, climate change and global C cycling.  相似文献   

Study of ready-to-use thin films for the chromatography of aflatoxins     

J P Petit 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1967,20(2):359-364

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