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61.
Krimigis SM Armstrong TP Axford WI Bostrom CO Fan CY Gloeckler G Lanzerotti LJ Keath EP Zwickl RD Carbary JF Hamilton DC 《Science (New York, N.Y.)》1979,206(4421):977-984
Measurements of the hot (electron and ion energies >/=20 and >/= 28 kiloelectron volts, respectively) plasma environment at Jupiter by the low-energy charged particle (LECP) instrument on Voyager 2 have revealed several new and unusual aspects of the Jovian magnetosphere. The magnetosphere is populated from its outer edge into a distance of at least approximately 30 Jupiter radii (R(J)) by a hot (3 x 10(8) to 5 x 10(8) K) multicomponent plasma consisting primarily of hydrogen, oxygen, and sulfur ions. Outside approximately 30 R(J) the hot plasma exhibits ion densities from approximately 10(-1) to approximately 10(-6) per cubic centimeter and energy densities from approximately 10(-8) to 10(-13) erg per cubic centimeter, suggesting a high beta plasma throughout the region. The plasma is flowing in the corotation direction to the edge of the magnetosphere on the dayside, where it is confined by solar wind pressure, and to a distance of approximately 140 to 160 R(J) on the nightside at approximately 0300 local time. Beyond approximately 150 R(J) the hot plasma flow changes into a "magnetospheric wind" blowing away from Jupiter at an angle of approximately 20 degrees west of the sun-Jupiter line, characterized by a temperature of approximately 3 x 10(8) K (26 kiloelectron volts), velocities ranging from approximately 300 to > 1000 kilometers per second, and composition similar to that observed in the inner magnetosphere. The radial profiles of the ratios of oxygen to helium and sulfur to helium (= 1 million electron volts per nucleon) monotonically increase toward periapsis, while the carbon to helium ratio stays relatively constant; a significant amount of sodium (Na/O approximately 0.05) has also been identified. The hydrogen to helium ratio ranges from approximately 20 just outside the magnetosphere to values up to approximately 300 inside; the modulation of this ratio suggests a discontinuity in the particle population at approximately 50 to 60 R(J). Large fluctuations in energetic particle intensities were observed on the inbound trajectory as the spacecraft approached Ganymede, some of which suggest the presence of a "wake." Five-and 10-hour periodicities were observed in the magnetosphere. Calculations of plasma flow velocities with the use of Compton-Getting formalism imply that plasma is mostly corotating to large radial distances from the planet. Thus the Jovian magnetosphere is confined by a plasma boundary (as was implied by the model of Brice and Ioannidis) rather than a conventional magnetopause. Inside the plasma boundary there exists a discontinuity at approximately 50 to 60 R(J) we have named the region inside this discontinuity the "inner plasmasphere." 相似文献
62.
MJ Thompson J Toomre ER Anderson HM Antia G Berthomieu D Burtonclay SM Chitre J Christensen-Dalsgaard T Corbard M DeRosa CR Genovese DO Gough DA Haber JW Harvey F Hill R Howe SG Korzennik AG Kosovichev JW Leibacher FP Pijpers J Provost EJ Rhodes J Schou T Sekii PB Stark PR Wilson 《Science (New York, N.Y.)》1996,272(5266):1300-1305
Splitting of the sun's global oscillation frequencies by large-scale flows can be used to investigate how rotation varies with radius and latitude within the solar interior. The nearly uninterrupted observations by the Global Oscillation Network Group (GONG) yield oscillation power spectra with high duty cycles and high signal-to-noise ratios. Frequency splittings derived from GONG observations confirm that the variation of rotation rate with latitude seen at the surface carries through much of the convection zone, at the base of which is an adjustment layer leading to latitudinally independent rotation at greater depths. A distinctive shear layer just below the surface is discernible at low to mid-latitudes. 相似文献
63.
Lanzerotti LJ Armstrong TP Gold RE Anderson KA Krimigis SM Lin RP Pick M Roelof EC Sarris ET Simnett GM Maclennan CG Choo HT Tappin SJ 《Science (New York, N.Y.)》1992,257(5076):1518-1524
Measurements of the hot plasma environment during the Ulysses flyby of Jupiter have revealed several new discoveries related to this large rotating astrophysical system. The Jovian magnetosphere was found by Ulysses to be very extended, with the day-side magnetopause located at approximately 105 Jupiter radii. The heavy ion (sulfur, oxygen, and sodium) population in the day-side magnetosphere increased sharply at approximately 86 Jupiter radii. This is somewhat more extended than the "inner" magnetosphere boundary region identified by the Voyager hot plasma measurements. In the day-side magnetosphere, the ion fluxes have the anisotropy direction expected for corotation with the planet, with the magnitude of the anisotropy increasing when the spacecraft becomes more immersed in the hot plasma sheet. The relative abundances of sulfur, oxygen, and sodium to helium decreased somewhat with decreasing radial distance from the planet on the day-side, which suggests that the abundances of the Jupiter-derived species are dependent on latitude. In the dusk-side, high-latitude region, intense fluxes of counter-streaming ions and electrons were discovered from the edge of the plasma sheet to the dusk-side magnetopause. These beams of electrons and ions were found to be very tightly aligned with the magnetic field and to be superimposed on a time- and space-variable isotropic hot plasma background. The currents carried by the measured hot plasma particles are typically approximately 1.6 x 10(-4) microamperes per square meter or approximately 8 x 10(5) amperes per squared Jupiter radius throughout the high-latitude magnetosphere volume. It is likely that the intense particle beams discovered at high Jovian latitudes produce auroras in the polar caps of the planet. 相似文献
64.
Krimigis SM Armstrong TP Axford WI Bostrom CO Fan CY Gloeckler G Lanzerotti LJ Keath EP Zwickl RD Carbary JF Hamilton DC 《Science (New York, N.Y.)》1979,204(4396):998-1003
The low-energy charged particle instrument on Voyager was designed to measure the hot plasma (electron and ion energies greater, similar 15 and greater, similar 30 kiloelectron volts, respectively) component of the Jovian magnetosphere. Protons, heavier ions, and electrons at these energies were detected nearly a third of an astronomical unit before encounter with the planet. The hot plasma near the magnetosphere boundary is predominantly composed of protons, oxygen, and sulfur in comparable proportions and a nonthermal power-law tail; its temperature is about 3 x 10(8) K, density about 5 x 10(-3) per cubic centimeter, and energy density comparable to that of the magnetic field. The plasma appears to be corotating throughout the magnetosphere; no hot plasma outflow, as suggested by planetary wind theories, is observed. The main constituents of the energetic particle population ( greater, similar200 kiloelectron volts per nucleon) are protons, helium, oxygen, sulfur, and some sodium observed throughout the outer magnetosphere; it is probable that the sulfur, sodium, and possibly oxygen originate at 1o. Fluxes in the outbound trajectory appear to be enhancedfrom approximately 90 degrees to approximately 130 degrees longitude (System III). Consistent low-energy particle flux periodicities were not observed on the inbound trajectory; both 5-and 10-hour periodicities were observed on the outbound trajectory. Partial absorption of > 10 million electron volts electrons is observed in the vicinity of the Io flux tube. 相似文献
65.
Post‐partum period has an important role in cows' breeding due to its effects on reproductive efficiency and subsequent pregnancy. Escherichia coli, Trueperella pyogenes (Arcanobacterium pyogenes), Fusobacterium necrophorum and Prevotella melaninogenicus are recognized as major pathogens associated with uterine endometrial lesions. The objective of this study was to identify these pathogens using the polymerase chain reaction (PCR) as a culture‐independent sensitive method. A total of 172 cows were examined 25–35 days post‐partum, and 128 cows were examined at 2 weeks later (39–49 days post‐partum). Uterine discharges were collected by covered plastic infusion pipettes. The prevalence of endometritis was greater in the first examination than the second (35.5% vs. 16%). E. coli was detected in eight of the samples, T. pyogenes was detected in 13 of the samples and F. necrophorum was detected in 11 of the samples. There was no positive sample of P. melaninogenicus. Uterine contamination by T. pyogenes and F. necrophorum in the first examination was higher than the second examination. T. pyogenes affected as a tendency the prevalence of clinical endometritis in first examination. Primiparous cows showed 4.02 times higher odds of clinical endometritis compared with second‐parity cows in first examination. A multiplex PCR protocol as a simple, less expensive, fast assay was introduced to identify E. coli, T. pyogenes and F. necrophorum. 相似文献
66.
A 7‐year‐old neutered male Jack Russell terrier‐cross was presented for signs of recurrent paraphimosis, despite previous surgical enlargement of the preputial ostium. Revision surgery was performed using a combination of preputial advancement and phallopexy, which resulted in complete and permanent coverage of the glans penis by the prepuce, and at 1 year postoperatively, no recurrence of paraphimosis had been observed. The combined techniques allow preservation of the normal penile anatomy, are relatively simple to perform and provide a cosmetic result. We recommend this combination for the treatment of paraphimosis in the dog, particularly when other techniques have failed. 相似文献
67.
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69.
SM Ossedryver GI Baldwin BM Stone RA McKenzie AW van Eps S Murray MT Fletcher 《Australian veterinary journal》2013,91(4):143-149
Three ponies continuously grazed a pasture containing an estimated 24% Indigofera spicata (wet weight basis) for 4–6 weeks in April and May 2004. They developed ataxia, paresis, depression, muscle fasciculations, dysphagia, ptyalism and halitosis. Two also developed corneal opacity. One pony recovered with supportive treatment, but the other two were euthanased and necropsied. Neuropathology was not present in either case, but both livers had periacinar and periportal lymphocytic infiltrations and hydropic degeneration of mid‐zonal hepatocytes, with mild to moderate periacinar necrosis also evident in one. The I. spicata contained 2.66 mg 3‐nitropropionic acid (3‐NPA)/g dry matter and 1.5 mg indospicine/g dry matter. Indospicine, but not 3‐NPA, was detected in serum from both of the euthanased ponies and indospicine was detected in heart, liver and muscle from the one pony in which this assay was performed. The clinical syndrome closely resembled ‘Birdsville horse disease’ caused by I. linnaei and was similar to that reported in horses poisoned by the closely related species I. hendecaphylla and to 3‐NPA poisoning of other animals, including humans. 3‐NPA is thought to cause this neurological syndrome. To our knowledge, this is the first authenticated report of I. spicata poisoning in grazing animals. We also report here the first published evidence that 3‐NPA and indospicine exist in naturalised I. spicata in Australia and of the formation of indospicine residues in tissues of animals grazing paddocks infested with I. spicata. 相似文献
70.
The development and integrity of equine pre‐antral follicles cultured in vitro with follicle‐stimulating hormone (FSH) supplementation
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MC Max CB Silva SM González AG Lindquist I Búfalo RG Gomes F Morotti CB Costa TRR Barreiros LA Lisboa MM Seneda 《Reproduction in domestic animals》2017,52(5):899-904
This study investigated the effects of different concentrations of FSH (10, 50, 100 and 200 ng/ml) in supplemented MEM+ on the development of equine pre‐antral follicles that were cultured in vitro for 2 or 6 days. The ovaries (n = 5) from mares in seasonal anoestrus were collected from a local abattoir. Ten ovarian tissue fragments of approximately 3 × 3 × 1 mm were obtained from each animal. The fragments were cultured in situ for 2 days (D2) or 6 days (D6) in MEM+ or MEM+ supplemented with FSH at four different concentrations, establishing the following 11 groups: control (D0); MEM + (D2); MEM + (D6); MEM + 10 ng/ml of FSH (D2); MEM + 10 ng/ml of FSH (D6); MEM + 50 ng/ml of FSH (D2); MEM + 50 ng/ml of FSH (D6); MEM + 100 ng/ml of FSH (D2); MEM + 100 ng/ml of FSH (D6); MEM + 200 ng/ml of FSH (D2); and MEM + 200 ng/ml of FSH (D6). Follicles were observed in only 9.65% (388 of 4,018) of the histological sections. Of the 861 follicles evaluated, 488 were in the primordial stage, and 373 were in various developmental stages; 59.7% were morphologically normal. Regarding the integrity of the pre‐antral follicles, the groups with 100 ng/ml FSH of 2‐days culture as well as 50, 100 and 200 ng/ml FSH of 6‐days culture provided the best results. In conclusion, the in vitro culture of abattoir‐derived equine ovarian fragments presented better morphological integrity when supplemented with FSH for 6 days, in comparison with the MEM culture group. However, no clear effects were observed with FSH regarding the promotion of activation from a primordial to a developing follicle. 相似文献