41 research outputs found
The influence of dietary lipid inclusion and daily ration on growth and smoltification in 1+ Atlantic salmon (Salmo salar) parr
Get PDFThe effects of diet regime on growth and smoltification in 1+ Atlantic salmon parr were studied. Two groups of approximately 400 salmon parr, in triplicate, were fed diets containing either 25% or 12.5% lipid from first-feeding. Two further treatments were fed either the 25% or 12.5% lipid diet for 98 days, after which they were fed the alternate diet. In a second experiment three groups of 550 parr, in duplicate, were fed at full, two-thirds or one-third of the manufacturers’ recommended ration, from first-feeding. All groups were maintained on their respective diet regimes until smoltification approximately one year after first-feeding. In experiment 1, lipid level had a significant effect on whole body lipid content. However growth and the incidence of smoltification was not affected by dietary lipid inclusion, with upper modal group fish from each treatment achieving a similar smolt status (in terms of condition factor and Na+, K+-ATPase) at seawater transfer. In experiment 2, growth and the incidence of smolt transformation increased with ration. Full and two-thirds ration fish maintained similar body lipid contents throughout the experiment, with that of the one-third ration fish lower only during early development, indicating that growth was controlled by the maintenance of a distinct lipid level. It is concluded that ration, and not dietary lipid inclusion, has a significant effect on growth and the decision to undergo smoltification in salmon parr
Biology of daphnia
No full textSwammerdam, the Dutch scientist, was the first author who took notice of any of the Daphniae. In his Historla Insectorum Generalis, 1669, he gave a description of a species of Daphnia, which resembled Daphnia pulex and which he named Pulex arboreus or arborencens. He stated that its beak was slender and pointed, and was used for drawing up food. He called the second antennae arms and described their motion as three-fold—rectilinear, unequal, and gyratory. He asserted that there were two eyes which seemed to be joined together. Merrett mentioned Daphnia in his Pinax rerum Britannicarum, published in 1677
The Hay river limestone, Northwest territories
No full textDuring the latter part of the 1949 field season, the author served as geologist on a California Standard Company field party which was sent to the Northwest Territories to make an examination of the Upper Devonian limestone strata exposed along the Hay river. The objects of this survey were: (1) to further the completion of the California Standard Company's geological map of possible "petroleum bearing formations in northern Alberta and the Northwest Territories, and, (2) to attempt a correlation of the Hay River limestone formation with the petroliferous limestones underlying Leduc, Alberta. The thesis of this paper is a detailed description of the Hay River limestone formation as it is exposed along the Hay river
Photoperiodic effects on precocious maturation, growth and smoltification in Atlantic salmon, Salmo salar
Get PDFCurrent Atlantic salmon farming practice induces early smoltification with artificial photoperiod regimes, however the importance of these photoperiods on parr maturation and interactions with smoltification are poorly understood. These questions were addressed in the present investigation, which examined the effects of photoperiod manipulation on the development, maturation and smoltification of individually tagged parr. Approximately 9000 salmon parr from a high grilsing stock were exposed to continuous light (LL) from first feeding. Three sub-groups of 2400 parr, each sub-group in triplicate tanks, were then exposed to an 8 week “winter photoperiod” (LD 10:14) starting on either the 18th May, the 9th August or the 20th September (defined respectively as the May, August and September groups). Following the artificial winter each group was returned to LL. A fourth group of 1600 fish was maintained in replicate tanks on LL throughout. The highest levels of maturation (approx. 20%) were recorded in the May group. August and September groups showed low levels of maturity
Progress and Controversy in Britain
No full textThe author presents a debate in which he and Sir Kenneth Barrill, chairman of a British Think Tank closely linked to government circles, discuss priorities in Adult Education. While Sir Kenneth argues forcefully to direct government priorities towards job retraining programmes, Mr. Groombridge favours a more all-encompassing education policy that can answer human needs other than job qualification.L’auteur présente un débat dans lequel lui et Sir Kenneth Berrill, président d’un conseil privé (Think Tank) étroitement lié au gouvernement discutent des priorités pour l’éducation des adultes. Tandis que Sir Kenneth défend la position selon laquelle les priorités gouvernementales doivent s’orienter vers des programmes de recyclage de main-d’oeuvre, B. Groombridge, quant à lui, défend une politique d’éducation plus vaste qui peut répondre à des besoins sociaux autres que ceux exigés par le marché du travail.El autor presenta un debate en el que él y Sir Kenneth Berrill, presidente de un consejo privado (Think Tank) estrechamente ligado al gobierno, discuten las prioridades para la educación de adultos. Mientras Sir Kenneth defiende la posición según la cual las prioridades deben orientarse hacia programas de reciclaje de la mano de obra, B. Broombridge defiende una política de educación más vasta, que puede responder a otras necesidades sociales que aquéllas exigidas por el mercado de trabajo
Bullying and homophobia in UK schools: A perspective on factors affecting resilience and recovery
No full textThis article reports the results of a three-year study focusing on the experiences of a sample of lesbian, gay, and bisexual (LGB) people in the United Kingdom who were victimized by their peers at school. Data collected from 190 LGBs suggested that experiences of victimization at school were both long-term and systematic, and were perpetrated by groups rather than by individuals. Subsequently, data collected from a sub-sample of 119 participants indicated that over 50 percent had contemplated self-harm of suicide at the time they were being harassed, and that 40 percent had engaged in such behavior at least once. As adults, participants were found to exhibit symptoms associated with negative affect when contrasted with heterosexual and non-victimized LGB peers. Seventeen percent exhibited symptoms associated with PTSD. However, the results also demonstrated that the majority of participants did not differ significantly from comparison groups in terms of self-esteem, and they had a positive attitude towards their sexual orientation. These findings are discussed with reference to the current literature about the development of resilience following exposure to violence and trauma
Effect of temperature on rate of egg and larval development in populations of Argia-Vivida Hagen (Odonata, Coenagrionidae) from habitats with different thermal regimes
No full textID: 5216; PT: J; DT: Article; C1: UNIV CALGARY,CALGARY T2N 1N4,ALBERTA,CANADA.; CR: BATEMAN MA, 1967, AUSTR J ZOOLOGY, V15, P1141 BERRILL NJ, 1935, PHIL T ROY SOC LON B, V225, P225 BOHLE HW, 1972, OECOLOGIA BERL, V10, P253 BRITTAIN JE, 1973, FRESHWATER BIOL, V3, P199 BRITTAIN JE, 1977, OIKOS, V29, P302 BRITTAIN JE, 1978, OIKOS, V30, P1 BRITTAIN JE, 1984, J ANIM ECOL, V53, P161 ELLIOTT JM, 1972, OECOLOGIA, V9, P47 ELLIOTT JM, 1978, FRESHWATER BIOL, V8, P51 FRIESEN MK, 1979, CAN ENTOMOL, V111, P665 HUMPESCH UH, 1980, J ANIM ECOL, V49, P317 HUMPESCH UH, 1980, J ANIM ECOL, V49, P927 HUMPESCH UH, 1982, OECOLOGIA BERLIN, V55, P285 LEGGOTT M, 1985, ODONATOLOGICA, V14, P201 LEGGOTT MA, 1984, THESIS U CALGARY CAL MARKARIAN RK, 1980, HYDROBIOLOGIA, V75, P81 MCLAREN IA, 1965, J GEN PHYSIOL, V48, P1071 MCLAREN IA, 1966, BIOL BULL, V131, P457 PILON JG, 1982, ODONTAOLOGICA, V11, P45 PILON JG, 1984, ADV ODONATALOGY, V2, P177 PRECHT HJ, 1973, TEMPERATURE LIFE PRITCHARD G, 1977, CAN ENTOMOL, V109, P1563 PRITCHARD G, 1982, ADV ODONATOLOGY, V1, P227 PRITCHARD G, 1985, ECOLOGY MOSQUITOES P, P237 RIVARD D, 1975, ODONATOLOGICA, V4, P271 SWEENEY BW, 1977, ECOLOGY, V58, P265 SWEENEY BW, 1978, LIMNOL OCEANOGR, V23, P461 TRAVIS J, 1980, GROWTH, V44, P167 VANNOTE RL, 1980, AM NAT, V115, P667 WALKER EM, 1953, ODONATA CANADA ALASK, V1 WARINGER JA, 1984, FRESHWATER BIOL, V14, P385; NR: 31; TC: 8; PA: RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA; J9: CAN J ZOOL; PG: 5; GA: AVW75; UT: ISI:A1985AVW7500017Source type: Print(0)http://ecommons.uwinnipeg.ca/archive/00000039/01/can_j_zoo_63_1985.pd
Multiaged redwood responds well to partial harvest and herbicide treatments
Get PDFChemical control of unwanted trees can be a cost-efficient tool for forest management and restoration. In California, United States, the response of merchantable conifers to hardwood control is poorly understood. We studied the tree growth of coast redwood (Sequoia sempervirens (Lamb. ex D. Don) Endl.) following herbicide frill treatment of competing tanoak (Notholithocarpus densiflorus (Hook. & Arn.) Manos, C.H. Cannon, & S. Oh), coinciding with a partial harvest of conifers. The radial growth of 420 redwoods in 45 plots was measured using increment cores. With or without partial harvesting, herbicide treatment of tanoak enhanced growth of most redwoods: 23% of redwoods in herbicide-only plots and 34% of redwoods in herbicide + harvest plots had ≥100% higher posttreatment basal area increment (BAI). In untreated plots, 67% of redwoods displayed declining BAI. The response of redwoods (the ratio of 8-year postharvest BAI to 8-year preharvest BAI) was 59% higher in herbicide-only plots and 108% higher in herbicide + harvest plots compared with untreated control plots over the same period. Redwoods with long crowns maintained rapid growth with or without treatment. Trees growing slowly before treatment exhibited the greatest response, provided that they had relatively long crowns and were not left in suppressed crown positions. Forest managers implementing partial harvesting and (or) chemical control of hardwoods can expect to maintain or promote rapid growth of most residual redwoods.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
Modeling the economic impact of welfare interventions in fish farming—A case study from the UK rainbow trout industry
No full textActions that aim to improve animal welfare are likely to involve costs for the producer, although at the same time such actions may improve the profitability of production. In this article we introduce a quantitative bio-economical approach for estimating the economic consequences for improving animal welfare in the aquaculture industry; for farmers and the industry as a whole. The decision tool can be used with different welfare indicators, different species and production systems. It can be used to rank the economic consequences of different techniques that aim to improve welfare. We illustrate the decision tool with a case study relating to the use of triploids in rainbow trout farming. We highlight the probability how the benefits gained from changes in bio-economical productivity factors, and consumers' willingness to pay can overcome the costs associated with implementing a specific welfare intervention
The Relationship Between Financial Distress and Well-Being: Exploring the role of self-employment
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