Assessing biotic integrity in a Mediterranean watershed: development and evaluation of a fish-based index     

M. F. MAGALHÃES  C. E. RAMALHO  & M. J. COLLARES-PEREIRA 《Fisheries Management and Ecology》2008,15(4):273-289

Abstract  Biological indicators for Mediterranean rivers are poorly developed. This study evaluates the effectiveness of the Index of Biotic Integrity approach (IBI) with fish assemblages in the Guadiana catchment, a typical Mediterranean watershed in Southern Portugal. Reference sites were selected from a set of 95 sites, using a multivariate approach. Fifty-five candidate metrics were screened for range, responsiveness, precision and redundancy. Final metrics included: proportion of native fish, number of intolerant and intermediate species, number of invertivore native fish, number of phyto-lithophilic and polyphilic species, and catches of exotics. The IBI scores correlated with composite gradients of human impact and differed significantly between reference and non-reference sites. Application of the IBI to an independent validation set with 123 sites produced results congruent with the development set and repeatable assessments at 22 sites showed concordance in IBI scoring. This application highlights the effectiveness of the IBI approach even with fish assemblages of limited diversity and ecological specialisation as in Mediterranean streams.  相似文献   

13 CONFORMATION OF TWO-YEAR-OLD THOROUGHBREDS AT AUCTION.     

EM  Santschi  MH Gotchey  ES Peterson  SR Leibsle  MK Clayton  . 《Veterinary surgery : VS》2003,32(6):601-601

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Veterinary medical manpower: supply-demand projections to 2020.     

G W McLaughlin  H E Bard  R B Talbot 《Journal of the American Veterinary Medical Association》1976,168(4):319-321

A supply projection model to estimate the number of veterinarians available through the year 2020 was developed. When projected available manpower was compared with the need for veterinary medical services, as estimated in a National Academy of Science study, a net shortage was indicated in each year between 1976 and 2020. The manpower supply available if 3 additional veterinary colleges were developed in the United States was also estimated. It was concluded that, even with the additional output of these colleges, the supply of veterinarians will not keep pace with future needs for veterinary services.  相似文献   

Nocturnal ovulation in the equine animal   总被引：2，自引：0，他引：2  

D M Witherspoon  R B Talbot 《The Veterinary record》1970,87(11):302-304

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Changes in plasma gonadotrophins, testosterone, prolactin, thyroxine and triiodothyronine concentrations in male Japanese quail (Coturnix coturnix japonica) of a heavy body weight line during photo-induced testicular growth and regression     

Henare SJ  Kikuchi M  Talbot RT  Cockrem JF 《British poultry science》2011,52(6):782-791

1. Simultaneous changes of cloacal gland area (CGA) and plasma luteinising hormone (LH), follicle stimulating hormone (FSH), testosterone (T), prolactin (PRL), thyroxine (T₄) and triiodothyronine (T₃) during photo-induced testicular growth and regression were measured in commercially bred Japanese quail from a heavy body weight line.

2. Somatically mature male Japanese quail were transferred from short days (light:dark 8L:16D) at 10°C, to long days (16L:8D) at 20°C; and sexually mature male Japanese quail were transferred from long to short days. All variables were measured at transfer and every 5?d thereafter for 35?d.

3. Transfer from short to long days caused significant increases in LH, FSH, T and testis weight (TW) after 5?d, and in CGA after 10?d. T₃ decreased after 5?d, whereas T₄ increased significantly after 25 long days and PRL did not undergo any consistent change. The testicular growth rate was k?=?0·1146.

4. Transferring quail from long to short days caused significant decreases in LH and FSH after 5?d, and decreases in T, TW and CGA after 10?d. T₄ decreased after 5?d whilst T₃ increased significantly by day 15. PRL decreased significantly after 10?d then rose before declining again. The testicular regression rate was k?=?0·0582.

5. The rates of photo-induced testicular development and regression in a strain of large Japanese quail did not differ from rates reported for other strains of quail. CGA was a better indicator of TW than plasma T concentrations during growth and regression. The role of PRL in photo-induced reproductive cycles in male Japanese quail remains to be determined.

6. The photoperiod-induced changes in gonad size and hormone concentrations, together provide valuable information that can be used in future studies of the endocrinology and neuroendocrinology of photoperiodism in birds.  相似文献   

Neural basis of the sense of flutter-vibration   总被引：3，自引：0，他引：3  

V B Mountcastle  W H Talbot  I Darian-Smith  H H Kornhuber 《Science (New York, N.Y.)》1967,155(762):597-600

Comparison of human detection thresholds for oscillatory movement of the skin of the hand with response properties of first-order myelinated mechanoreceptive afferents from the monkey's hand, activated in an identical stimulus pattern, indicates that flutter-vibration is a dual form of mechanical sensibility, served peripherally by two different sets of fibers.  相似文献   

Multiple representations of pain in human cerebral cortex   总被引：38，自引：0，他引：38  

J D Talbot  S Marrett  A C Evans  E Meyer  M C Bushnell  G H Duncan 《Science (New York, N.Y.)》1991,251(4999):1355-1358

The representation of pain in the cerebral cortex is less well understood than that of any other sensory system. However, with the use of magnetic resonance imaging and positron emission tomography in humans, it has now been demonstrated that painful heat causes significant activation of the contralateral anterior cingulate, secondary somatosensory, and primary somatosensory cortices. This contrasts with the predominant activation of primary somatosensory cortex caused by vibrotactile stimuli in similar experiments. Furthermore, the unilateral cingulate activation indicates that this forebrain area, thought to regulate emotions, contains an unexpectedly specific representation of pain.  相似文献   

A technique for electrically stimulating extrusion of spermatophores from the lobster, Homarus americanus     

Marcia J. Kooda-Cisco  Prue Talbot   《Aquaculture (Amsterdam, Netherlands)》1983,30(1-4):221-227

A technique for electrically inducing spermatophore extrusion from live lobsters (Homarus americanus) is described. When a 12-V stimulus is applied around the coxa of the fifth walking leg, a single spermatophore is extruded through the gonopore. The sperm in extruded spermatophores are morphologically normal and undergo normal acrosome reactions. The technique provides a ready source of viable sperm for in vitro studies on fertilization and for artificial insemination of freshly molted female lobsters. The spermatophore itself is a natural package for sperm storage and may be useful in the future development of lobster sperm banks.  相似文献   

Book reviews and notices     

Malcolm Jobling  Victor øiestad  Clive Talbot  Chris Carter 《Aquaculture International》1995,3(1):66-75

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Relative bioavailability of zinc in supplemental inorganic and organic sources for Nile tilapia Oreochromis niloticus fingerlings     

M.V. DO CARMO E SÁ  L.E. PEZZATO  M.M. BARROS  & P. DE  MAGALHÃES PADILHA 《Aquaculture Nutrition》2005,11(4):273-281

A 90‐day feeding experiment was conducted with sex reversed Nile tilapia (Oreochromis niloticus) fingerlings fed purified or practical diets supplemented with different zinc sources to evaluate fish growth performance and zinc and iron retention in fish bones, fillets, liver, skin and eyes. The relative bioavailability value (RBV) of zinc in the supplemental sources tested was also calculated. Fish were fed with isonitrogenous and isoenergetic purified or practical diets supplemented with 150 mg Zn kg^?1, as zinc sulphate monohydrate (ZnSO₄), zinc oxide (ZnO) or zinc amino acid complex (Zn‐AA). The feeding trial was conducted in 30, 50 L aquaria where four 0.66 ± 0.01 g (mean ± SD) fingerlings were initially stocked. No significant differences were observed for any growth performance variables (P > 0.05). In practical diets, only ZnSO₄ and ZnO presented bone zinc retention similar to that for the standard zinc source. Zinc concentration in the bone of fish fed practical diet supplemented with Zn‐AA (171 ± 3.62 μg g^?1) was significantly lower than that verified for the practical diets supplemented with the standard zinc source (200 ± 17.7 μg g^?1) or with ZnSO₄ (204 ± 19.9 μg g^?1). Assuming the concentration of zinc in bones as the response criterion, the supplemental zinc RBV from ZnSO₄ (105%) was higher than the RBV for Zn‐AA (95.1%) or ZnO (94.9%). Iron concentration in the bones of animals fed the non‐zinc‐supplemented purified diet was significantly higher than that observed for purified diet supplemented with Zn‐AA (P < 0,05). The results of the present work allowed us to conclude that ZnSO₄ in relation to ZnO or Zn‐AA was the supplemental zinc source with higher zinc bioavailability to Nile tilapia.  相似文献