Large-scale rearing of Atlantic halibut, Hippoglossus hippoglossus L., yolk sac larvae: effects of flow rate on growth, survival and accumulation of bacteria     

I Opstad  Ø Bergh  A B Skiftesvik 《Aquaculture Research》1998,29(12):893-898

The role of flow rate in large-volume production units (2800 L silos) for Atlantic halibut, Hippoglossus hippoglossus L., larvae was studied. Correlations between flow rate, bacterial numbers (a measure of water quality), the larval growth and development rates, and mortality were assessed. The experiment included a total of six silos, two each at three different flow rates. Flow rate and mortality were positively correlated: the number of dead larvae on day 30 was highest (i.e. 2200 and 2000) in the silos with highest flow rate (8L min^?1) and lowest (i.e. 1300 and 1200) in the silos with the lowest flow rate (2L min^?l). Larval weight was negatively correlated with flow rate: on day 30, the mean dry weight was 968 μg in the silo with the lowest flow rate and 820 μg in the silo with highest flow rate. Yolk sac utilization efficiency was 92% in the silo with the lowest flow rate and 72% in the silo with the highest flow rate. The number of bacteria were highest (2.7-10⁶mL^?1) in the incubators with the lowest flow rate.  相似文献   

Effects of nutrition and soil water availability on water use in a Norway spruce stand     

Phillips N  Bergh J  Oren R  Linder S 《Tree physiology》2001,21(12-13):851-860

We investigated effects of nutrition and soil water availability on sap flux density, transpiration per unit leaf area (EL), and canopy stomatal conductance (GS) of Norway spruce (Picea abies L. (Karst.)) in northern Sweden during the 1996 growing season. Our objectives were to determine (1) if artificially imposed drought (65% rain diversion) reduces soil water sufficiently to cause physiological limitations to whole-tree and plot-scale water transport, and (2) whether increased capacity for water transport resulting from fertilization-induced increases in leaf (> 3-fold) and sapwood areas (> 2.3-fold) deplete soil water sufficiently to cause a negative feedback on GS and EL. We monitored soil water content (theta) and soil water potential (PsiS) in control (C), drought (D), fertilized (F) and irrigated + fertilized (IL) treatment plots, along with site meteorological conditions. Ten trees per plot were monitored for sap flow. Although there were significant treatment differences in mean daily EL (C > D > F; P < 0.01) and GS (C > D > F; P < 0.05), variation in absolute magnitudes was small. Therefore, transpiration differences on a unit ground area basis (EC) were nearly proportional to leaf area differences. Precipitation was well distributed throughout the study period and so PsiS remained high, except during short dry periods in Plot F when it declined rapidly. Thus, although soil water was not limiting to GS, EL or EC when precipitation was uniformly distributed throughout the growing season, we cannot conclude that water availability would not limit GS in fertilized stands if the seasonal distribution of precipitation were altered.  相似文献   

Reactivity of anthocyanins and pyranoanthocyanins. Studies on aromatic hydrogen-deuterium exchange reactions in methanol     

Jordheim M  Fossen T  Songstad J  Andersen ØM 《Journal of agricultural and food chemistry》2007,55(20):8261-8268

Reactivity studies involving anthocyanin structures and their equilibrium forms will lead to better understanding of the properties of these antioxidants. Hydrogen-deuterium (H --> D) exchange reactions at various sites of the 3-glucosides of delphinidin (1), petunidin (2), malvidin (3), and the corresponding 3-glucosides of carboxypyranodelphinidin (4), carboxypyranopetunidin (5), carboxypyranomalvidin (6), and the flavonol quercetin 3-O-(6-alpha-rhamnopyranosyl-beta-glucopyranoside)(7) have been examined at room temperature in pure CD 3OD and in CD 3OD acidified with CF 3CO 2D. The H --> D exchange rate constants of H-6 and H-8 of 2 determined from (1)H NMR integration data were found to be independent upon pigment concentration (up to 4 x 10 (-2) M) and trifluoroactic acid concentration (0-15%, v/v), respectively. This suggest that these reactions follow first-order kinetics and unexpectedly to be independent of the acid concentration. H-6 and H-8 of the flavylium cation A-rings of 1- 3, and in the corresponding hydrogens of the hemiketal forms, exchanged with half-lives of approximately 100 h ( 1) and approximately 50 h ( 2 and 3), respectively. The pyranoanthocyanins (4-6) experienced no H --> D exchange for the analogous hydrogens, but H --> D exchange of H-beta (H-4)(t 1/2 approximately 25 h) for these compounds was observed. Only H-8 underwent significant H --> D exchange in 7. It is concluded that a stabilization of the sigma-complexes, assumed to be the intermediates in the reactions, takes place for the common anthocyanins (1-3) contrary to the pyranoanthocyanins (4-6).  相似文献   

A stochastic model simulating milk fever in a dairy herd     

Østergaard S  Sørensen JT  Houe H 《Preventive veterinary medicine》2003,58(3-4):125-143

A simulation model was developed to evaluate the long-term effect of control strategies against milk fever (MF); here, we present the base model and sensitivity analyses. The representation of the within-herd dynamics was based on the existing SimHerd II model. Because of the relationships between MF and other diseases, the new model (called “SimHerd III”) includes diseases common in a dairy herd.

The cow level risk factors modelled were: base risk in the herd, parity, milk-yield potential, lactational disease recurrence, disease interrelationships, body condition and season. The diseases include clinical cases of MF, dystocia, downer-cow syndrome, retained placenta, metritis, displaced abomasum, ketosis and mastitis. The effects of diseases were represented by daily milk yield, daily body weight, daily feed intake, risk of stillbirth, conception probability, decision on culling, death and immediate removal. Simulated technical results showed that the herd effects of reduced risk of MF differed according to the reproductive efficiency in the herd. These interactions between reproduction efficiency and the effect of reduced base risk of MF were related to differences in how the simulated herds reacted to the reduction in replacements caused by MF.

In the sensitivity analysis, eight potential key parameters were changed to their lowest and highest expected values retrieved from the literature. When measuring the sensitivity on milk production in the herd (as the economically most important technical effect), the model seemed most sensitive to the uncertainty of effect of MF on death risk and MF-recurrence risk.  相似文献   

Long‐Term Outcome in Dogs After Circumcostal Gastropexy or Gastrocolopexy for Gastric Dilatation With or Without Volvulus     

ANNA V. EGGERTSDÓTTIR DVM  PhD  MARIANNE LANGELAND DVM  PhD  BJØRN FUGLEM DVM  ANE MOHN DVM  ØYVIND STIGEN DVM  PhD 《Veterinary surgery : VS》2008,37(8):809-810

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The effect of passive immunization on active immunity against Clostridium perfringens type D in lambs   总被引：1，自引：0，他引：1  

M W Odendaal  J J Visser  N Bergh  W J Botha 《The Onderstepoort journal of veterinary research》1989,56(4):251-255

Lambs in different stages of development of active immunity against Clostridium perfringens type D were treated with partially purified immunoglobulin in an attempt to superimpose a passive immunity on an existing or developing active immunity. Three different studies were undertaken to determine the impact of partial purified immunoglobulins on these vaccinated animals. In 2 of the 3 studies, active immunity was induced by administering the normal routine enterotoxaemia vaccinations and allowing the basic immunity to become established, for a period ranging from 2 weeks for the animals in study 1 and 4 months for those in study 2, before passive immunization with the partially purified immunoglobulins took place. An increase in the epsilon antibody titre occurred in each of the 2 studies after the animals were passively immunized with immunoglobulin, though this increase was not statistically significant (P greater than 0.05). In the 3rd study, when the animals were given the initial vaccination of the Onderstepoort enterotoxaemia oil adjuvant vaccine together with the immunoglobulin, an immediate increase in the epsilon antitoxin titre occurred that was statistically significant (P less than 0.05) 2-14 days after administration. No negative effects were noted on the development of an initial active immunity or an existing active immunity against Clostridium perfringens type D when they were passively immunized with partially purified immunoglobulin.  相似文献   

The morphological evolution of galaxies     

Abraham RG  van Den Bergh S 《Science (New York, N.Y.)》2001,293(5533):1273-1278

Many galaxies have taken on their familiar appearance relatively recently. In the distant Universe, galaxy morphology deviates significantly (and systematically) from that of nearby galaxies at redshifts (z) as low as 0.3. This corresponds to a time approximately 3.5 x 10(9) years in the past, which is only approximately 25% of the present age of the Universe. Beyond z = 0.5 (5 x 10(9) years in the past), spiral arms are less well developed and more chaotic, and barred spiral galaxies may become rarer. At z = 1, around 30% of the galaxy population is sufficiently peculiar that classification on Hubble's traditional "tuning fork" system is meaningless. On the other hand, some characteristics of galaxies have not changed much over time. The space density of luminous disk galaxies has not changed significantly since z = 1, indicating that although the general appearance of these galaxies has continuously changed over time, their overall numbers have been conserved.  相似文献   

Mortality of scallop spat in cultivation, infested with tube dwellingbristle worms, Polydora sp.     

S. Mortensen  T. Meeren  A. Fosshagen  I. Hernar  L. Harkestad  L. Torkildsen  Ø. Bergh 《Aquaculture International》2000,8(2-3):267-271

Between 1995 and 1997, a traditional Norwegian oyster poll with an attachednursery was used for the production of scallop (Pecten maximus) spat.During summer 1997, four batches of 2 mm scallop spat were placed in thenursery. In June, hydroids (Obelia) caused problems with fouling andaccumulation of sediment in the nursery. Thereafter, the scallop spat wereheavily infested with tube dwelling polychaets (Polydora sp.). Thepolychaets were both introduced with poll water and reproduced inside thenursery. Infested spat suffered high mortalities. Although the spat could have been affected by the hydroids, as well as shortage of food, Polydorainfestations were considered the main cause of the mortalities. Dead andinfested spat were continuously sorted out and discarded, but the infestationproblems persisted. As a result, the scallop spat did not represent anycommercial value for the company, and in September, the nursery wasemptied. In total, approximately one million spat – representing onethird of Norway's intensive scallop spat production in 1997, was lost.  相似文献   

Covariation in shape and foraging behaviour in lateral plate morphs in the three‐spined stickleback     

O. Bjærke  K. Østbye  H. M. Lampe  L. A. Vøllestad 《Ecology of Freshwater Fish》2010,19(2):249-256

Bjærke O, Østbye K, Lampe HM, Vøllestad LA. Covariation in shape and foraging behaviour in lateral plate morphs in the three‐spined stickleback. Ecology of Freshwater Fish 2010: 19: 249–256. © 2010 John Wiley & Sons A/S Abstract – In three‐spined stickleback (Gasterosteus aculeatus) colonisation of freshwater has led to rapid evolution in various morphological and behavioural traits. Examples are reduction in lateral plate number and increased benthic foraging. These changes are believed to result from natural selection, but the evolutionary mechanisms driving behavioural changes and how such changes are associated with phenotypes, are poorly understood. Here, we study three different lateral plate morphs from a brackish water lake and one morph from a river upstream. We investigate if the lateral plate morphs differ in overall body shape and then experimentally test how foraging behaviour differ among morphs and with body shape. Foraging behaviour is measured as the consumption efficiency of benthic and pelagic prey types. The results show that lateral plate morphs differ in overall body shape and that body shape significantly co‐varies with foraging behaviour.  相似文献   

Surgical Correction of Angular and Torsional Metatarsal Deformity With Cylindrical Osteotomy and Locking Compression Plates in a Calf     

Jennifer A. Schleining DVM  MS  Diplomate ACVS  Mary Sarah Bergh DVM  MS  Diplomate ACVS & ACVSMR 《Veterinary surgery : VS》2014,43(5):563-568

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