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141.
To explain the elevated osmium isotope (186Os-187Os) signatures in oceanic basalts, the possibility of material flux from the metallic core into the crust has been invoked. This hypothesis conflicts with theoretical constraints on Earth's thermal and dynamic history. To test the veracity and uniqueness of elevated 186Os-187Os in tracing core-mantle exchange, we present highly siderophile element analyses of pyroxenites, eclogites plus their sulfides, and new 186Os/188Os measurements on pyroxenites and platinum-rich alloys. Modeling shows that involvement in the mantle source of either bulk pyroxenite or, more likely, metasomatic sulfides derived from either pyroxenite or peridotite melts can explain the 186Os-187Os signatures of oceanic basalts. This removes the requirement for core-mantle exchange and provides an effective mechanism for generating Os isotope diversity in basalt source regions.  相似文献   
142.
143.
High Correlation coefficients have been found in the application of the formula:
Fresh weight of ripe berry (g)=(Total number of achenes?C)F(Number of achenes per cm2 of surface
to data for a large number of strawberries from nine cultivars. Of the terms in the equation (Total no. of achenes — C) was found to be different in different cultivars and to be related to the position of the berry on the inflorescence, but there was no constant relationship between the achene numbers in the different ranks of berry. Whether the numbers of achenes per berry can be altered by environmental or cultural treatments was not resolved. F, a term having the dimensions of weight per area, represents weight per unit area of berry surface and seems to be constant amongst plants of a cultivar subject to uniform treatment, but differs between cultivars and treatments.The number of achenes per cm2 of surface on ripe berries is a measure of berry development in the fruiting season and may be affected by environmental and managerial factors and by internal competition between fruits and leaves on the same plant.The interactions of these factors on berry size enable two stages to be recognised at which size is determined, namely during flower formation, when achene numbers and possibly F are fixed, and during fruit development after pollination when the term for spatial distribution of achenes is settled.It is suggested that an examination of the effects of different treatments on each of the size components might enable a distinction to be drawn between the influence on yield of genetic characteristics on the one hand and intrinsically variable characteristics subject to external influence on the other hand, thus clarifying the type of research and/or development needed to enable growers to achieve maximum yields.  相似文献   
144.
The suckling behaviour in four consecutive litters of a captive female Dendrohyrax arboreus is described. The young showed teat constancy which was established by day four of age without aggressive interactions, and maintained until weaning in all multiple litters. A preference for the more productive inguinal teats was apparent. Frequency of suckling bouts decreased with time but their duration increased. Most suckling occurred shortly after dawn and before dusk. The female showed decreasing maternal care in each successive litter.  相似文献   
145.
Cell-mediated immunity (CMI) diagnostic tests, such as the gamma interferon enzyme-linked immunosorbent assay (IFN-gamma ELISA) and the Johnin skin test, have the potential to detect animals infected with Mycobacterium avium subspecies paratuberculosis (MAP) early in the course of the disease. While these CMI tests tend to be relatively specific in noninfected flocks, in MAP-infected flocks, these tests often identify animals that cannot be confirmed infected by any other reference test, including necropsy and culture. The aim of this study was to determine if antigen exposure by inhalation or oral ingestion of killed MAP organisms would cause a detectable CMI response in sheep. Forty-eight lambs 4 months of age were randomly divided into a control group, an orally exposed group (dosed with 1 x 10(10) autoclaved MAP organisms 3 times), and an inhalation-exposed group (dosed once with 1 x 10(5) dead organisms). Lambs were skin tested and/or bled pre-exposure and 1, 2, 3, 4, and 12 months postexposure. No significant difference was seen with either the oral- or inhalation-exposed groups of lambs versus controls with either the IFN-gamma ELISA or the skin test at any time pre- or postexposure. These results suggest that infection/invasion of MAP organisms must occur in order to have a positive skin test or IFN-gamma ELISA beyond the false-positive rate. Simple exposure is not enough to elicit a detectable CMI response.  相似文献   
146.
The efficiency of traps baited with synthetic sex attractants, (Z)-9- and (Z)-11-tetradecenyl acetates, for Panolis flammea (Denis & Schiffermüller) (Lepidoptera: Noctuidae) was tested with respect to trap design, capacity, height, alignment, position and dose of lure. For optimum catches, traps should not be obstructed by vegetation, and can be placed most conveniently in forest rides. The most important features of trap design were a heavy surface coating of sticky retentive material and a large catching area. The efficiency of capture decreased rapidly when 40 or more moths were present on a sticky surface of area 380 cm2. Numbers of moths caught increased regularly as the dose of lure increased from 1 μg to 5 mg. Males of Orthosia gothica (L.) (Lepidoptera: Noctuidae) were frequently caught in numbers similar to those of P. flammea in the same traps during the flight period of the latter insect. Increasing the relative quantity of the minor component, (Z)-11-tetradecenyl acetate, reduced catches of P. flammea, but not always those of O. gothica.  相似文献   
147.
148.
Margaret A.  Blaik  DVM  R. Reid  Hanson  DVM  Steven A.  Kincaid  DVM  MS  PhD  John T.  Hathcock  DVM  MS  Judith A.  Hudson  DVM  PhD  Debra K.  Baird  DVM  PhD 《Veterinary radiology & ultrasound》2000,41(2):131-141
The objective of this study was to define the normal gross anatomic appearance of the adult equine tarsus on a low-field magnetic resonance (MR) image. Six radiographically normal, adult, equine tarsal cadavers were utilized. Using a scanner with a 0.064 Tesla magnet, images were acquired in the sagittal, transverse and dorsal planes for T1-weighted and the sagittal plane for T2-weighted imaging sequences. Anatomic structures on the MR images were identified and compared with cryosections of the imaged limbs. Optimal image planes were identified for the evaluation of articular cartilage, subchondral bone, flexor and extensor tendons, tarsal ligaments, and synovial structures. MR images provide a thorough evaluation of the anatomic relationships of the structures of the equine tarsus.  相似文献   
149.
A 13‐year‐old neutered male English Springer Spaniel was presented to The Ohio State University Veterinary Medical Center for evaluation of severe anemia. Upon blood smear review, approximately 50% of the platelets contained single to multiple variably sized clear vacuoles. Transmission electron microscopy of the platelets revealed hallmark features of autophagy, including membrane‐lined vesicles and vacuoles containing membrane whorls and degrading organelles. While autophagy has been demonstrated in a wide range of eukaryotic cells for decades, reports of platelet autophagy are lacking. This case report illustrates atypical platelet vacuolation with electron microscopic features characteristic of autophagy.  相似文献   
150.
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