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11.
Abstract – The reproductive biology of three species of rainbowfish (Melanotaeniidae) in northeastern Australian rainforest streams was investigated. Two species, Melanotaenia eachamensis and Cairnsichthys rhombosomoides are endemic to the area, whereas the third, M. splendida splendida, is more widespread. The species were all highly fecund, producing many hundreds of eggs between 1.10 and 1.24 mm in diameter. Melanotaenia eachamensis was the most fecund, produced the largest eggs of the three species, and consequently exhibited the greatest maternal investment (as measured by gonadosomatic index). The majority of reproductive effort occurred during the dry season, although reproductively active fish were present year-round for each of the species, but particularly so for M. s. splendida and C. rhombosomoides. No evidence for a role by temperature or photoperiod as environmental cues for reproduction was found, and it was suggested that gonad development was strongly tied to somatic growth. The concentration of reproduction to the dry season ensures that larvae are produced during a period of relatively stable and benign physical conditions. Comparison of temporal changes in gonadosomatic index values suggest that the spawning season of M. eachamensis , which occurs in high-elevation streams, is more restricted and commences about 1 month earlier than either other species. A similar phenology was observed for the M. s. splendida population found at high elevation and highlights the potential for spatial differences in stream productivity to influence life history. Note 相似文献
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Abstract – Otoliths were used to explore the timing of annulus formation in Barbus sclateri. Lapillus exhibited opaque and translucent zones whose combination was formed once a year. Opaque zones appeared formed from July and January, and the translucent ones from February to June. We describe a procedure to assess age by using the number of annulii, the condition of the otolith's edge and the capture date. The use of otoliths for age determination in this cyprinid endemic to the Iberian Peninsula provides a useful alternative to the traditional methods of scale reading. Note 相似文献
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Because vanadium (V) is easily reduced to a cationic form within plant cells, data from resin-extraction of soil were analysed for evidence of interactions between V and the resin-extractable concentrations of magnesium (Mg) and calcium (Ca) on soybean seed yield. Three varieties, 9091, 9061 and 704, were grown over a 3-year period in a corn–soybean–wheat rotation. Surface soil samples (0–15 cm) were extracted with ion-exchange resins, extracts were analysed by inductively coupled plasma methods (ICP), and the results were regressed against seed yield using SAS PROC STEPWISE analysis using forward selection, backward elimination and maximum R2 routines. The seed yield of each variety showed a correlation with a unique set of resin-extractable concentrations of V, phosphorus (P), Mg and Ca, and the V:(V + P), Mg:(Mg + Ca), Mg:(Mg + 1000 V) and Ca:(Ca + 1000 V) ratios. Variety 9091 was most sensitive to the Mg:(Mg + Ca) ratio. Variety 9061 was most sensitive to extractable V and to the V:(V + P) ratio. Variety 704 was sensitive to extractable P, V and Ca and the Mg:(Mg + 1000 V) ratio. For variety 9091, Mg fertilization (not currently practised) may be an economical practice, whereas P fertilization of 704 may not be economical. Each regression technique varied slightly in identification of important factors in seed yield. Concentrations and ratios of resin-extractable elements in soil provide insights into optimal genotype selection and possible management alternatives for a given soil. 相似文献
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A. Bhogal A. Bhogal M.A. Shepherd D.J. Hatch L. Brown S.C. Jarvis 《Soil Use and Management》2001,17(3):163-172
Abstract. The ability of two nitrogen cycle models, of contrasting complexity, to predict N mineralization from a range of grassland soils in the UK, was evaluated. These were NCYCLE, a simple mass balance model of the N cycle in UK grasslands, and CENTURY, a more complex model simulating long-term C, N, P & S dynamics in grassland ecosystems. The models were tested using field measurements of net N mineralization from a range of grassland soils (differing in soil type, history & management practice), obtained over a 2 year period using a soil core incubation technique. This method was considered to measure the total net release of mineral N from the soil organic matter over a specified time, including N which may have been recycled several times. NCYCLE consistently under-estimated mineralization rates at all sites. By contrast, there was some correlation between CENTURY predictions of net N mineralization and field measurements. This may have reflected the different abilities of the two models to simulate N recycling. Neither model, however, was able to predict adequately the effect of cultivation and reseeding on net N mineralization. 相似文献
16.
W W Chan K Y Chen H Liu L S Wu J H Lin 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2001,63(10):1057-1062
Since the International Society of Veterinary Acupuncture (IVAS) was founded in 1974, acupuncture (AP) has received greater acceptance by veterinary professionals throughout the world. This article introduces some important animal diseases that respond well to AP therapy. These include resuscitation of small animals, treatment of anoestrous gilts and sows, bovine reproductive disease, canine vertebral problems and equine backpain, etc. Conventional medicine considers these to be difficult cases to treat. Veterinarians have become more aware of the benefits of AP especially for those diseases, thanks to the efforts of experienced practitioners and scientists, and the many published reports on veterinary AP that have introduced some good indications for AP therapy in veterinary practice. Possible mechanisms behind the effectiveness of AP are discussed. This article aims to introduce veterinarians to good indications for AP to initiate their interest in the practice of AP. Although this is a rapidly expanding field, a long march must begin with one step. We wish this article to be the shoes for such a march. For more information on veterinary AP, contact IVAS , P.O. Box 1478, Longmont, CO.. 80502, USA (http://www.ivas.org), or your national veterinary acupuncture society (http://www.komvet.at/ ivadkom/vapsocs.htm). 相似文献
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Disseminated Aspergillus terreus infection was diagnosed in ten previously healthy adult dogs--nine German shepherds and one dalmatian. The disease was characterized by the presence of multiple granulomas and infarcts in a wide range of organs. The kidney, spleen, and skeletal system were most commonly and severely affected. Fungal hyphae were demonstrated in large numbers within granulomas and thrombi, and A. terreus was readily isolated by culture. This disseminated mycosis appears unique; in this series of cases there was no apparent predisposing factor, portal of entry, or primary focus for dissemination of the infection. 相似文献