Breeding of Panulirus longipes cygnus George under natural and controlled conditions

1976 ◽  
Vol 27 (3) ◽  
pp. 499 ◽  
Author(s):  
RG Chittleborough
Keyword(s):  
Ambient Temperature ◽  
Water Temperature ◽  
Population Size ◽  
Natural Population ◽  
Commercial Fishing ◽  
Breeding Stock ◽  
The Past ◽  
Adult Females ◽  
Abundant Food ◽  
Mean Size

Fertilization of eggs is external: the female does not need to be newly moulted to be mated. The incubation period of eggs (19-68 days) varied inversely with water temperature, being longest at 19� C and shortening towards an asymptote at 25� C. Most adult females breed every year. When given abundant food, 77% of those breeding in aquaria at ambient temperature had two successive spawnings in a breeding season, whereas in a relatively crowded part of the natural population less than 12% of the breeding females spawned twice in a season. When held at a constant temperature of 25� C and given abundant food, adult females bred continuously, averaging six spawnings and three moults each year. In the natural population, size at first breeding and mean size of breeding females did not vary with depth but differed from one locality to another. At the Abrolhos Islands where the present density of breeding stock is highest, adults appear to be stunted and fecundity is relatively low. This situation may have existed to some extent in other parts of the population before heavy commercial fishing of the past 20 years or more reduced the density of the breeding stock to present levels. The operation of density-dependent regulation of fecundity in this population is discussed.

Quantitative Analysis of Microstructure and Modeling of Sintering

2009 ◽  
Vol 624 ◽  
pp. 1-18 ◽  
Author(s):  
Jean Marc Chaix
Keyword(s):  
Image Analysis ◽  
Input Data ◽  
3D Imaging ◽  
Point Of View ◽  
Size Distributions ◽  
Practical Point ◽  
The Past ◽  
Modeling Techniques ◽  
Mean Size ◽  
Sintering Mechanisms

Microstructure is the key scale to understand and describe sintering mechanisms and their consequences at the macroscopic level. As modeling techniques are continuously developing, the need for input data and comparison with more and more accurate descriptions of the evolution is expected to create a growing demand for quantitative microstructure data. Image analysis is the classic way to get these data. This paper reviews the practical use and progresses of this old technique in the sintering literature during the past and recent years. The place of basic tools and more recent ones, such as 3D imaging, are discussed from a practical point of view accounting from sintering models needs: mean size and size distributions in pores and grains, homogeneity, sintering trajectories…

Production, Mortality, And Sustainable Yield Of Northwest Atlantic Harp Seals (Pagophilus groenlandicus)

1978 ◽  
Vol 35 (9) ◽  
pp. 1249-1261 ◽  
Author(s):  
G. H. Winters
Keyword(s):  
Population Size ◽  
Total Population ◽  
Historical Data ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Natural Mortality ◽  
Northwest Atlantic ◽  
The Past ◽  
Relative Contribution ◽  
Pagophilus Groenlandicus

From recent and historical data the natural mortality rate of adult harp seals (Pagophilus groenlandicus) is estimated to be 0.10 which is within the range of previous estimates (0.08–0.11). New estimates of bedlamer and 0-group natural mortality rates were not significantly different from those of adult seals. Pup production estimates from survival indices agreed well with those from sequential population analyses and indicated a decline from about 350 000 animals in the early 1950s to about 310 000 animals in the early 1970s. Over the same period the 1+ population size declined from 2.5 to 1.1 million animals but has been increasing at the rate of 3%/yr since the introduction of quotas in 1972. The relative contribution of the "Front" production to total ("Front" plus Gulf) production during the past decade has fluctuated from 49 to 87%, the average of 64% being very similar to the 61% obtained previously. These fluctuations suggest some interchange between "Front" and Gulf adults and it is concluded that homing in the breeding areas is a facultative rather than obligatory aspect of seal behavior. Thus the heavier exploitation of the "Front" production is probably sufficiently diffused into the total population to avoid serious effects on "Front" production. The maximum sustainable yield of Northwest Atlantic seals harvested according to recent patterns is estimated to be 290 000 animals (80% pups) from a 1+ population size of 1.8 million animals producing 460 000 pups annually. The sustainable yield at present levels of pup production (335 000 animals) is calculated to be 220 000 animals which is substantially above the present TAC of 180 000 animals and coincides with present harvesting strategies designed to enable the seal hunt to increase slowly towards the MSY level. Key words: mortality, production, sustainable yield, population dynamics, marine mammal

Predation by Sharks on the Grey Seal (Halichoerus grypus) in Eastern Canada

1983 ◽  
Vol 40 (3) ◽  
pp. 267-271 ◽  
Author(s):  
Paul Brodie ◽  
Brian Beck
Keyword(s):  
Key Words ◽  
Population Size ◽  
Halichoerus Grypus ◽  
Longline Fishery ◽  
Grey Seal ◽  
Eastern Canada ◽  
The Past ◽  
Harbour Seals ◽  
Commercially Important ◽  
Important Fish

The increase in population size of the grey seal (Halichoerus grypus) off eastern Canada over the past 20 yr may be attributed to a decrease in shark stocks, their supposed predators. Reduction of the shark population is presumed to have resulted from a directed longline fishery and, of greater significance, from a change in the fishery for swordfish (Xiphias gladius) from selective harpooning to pelagic longlining, which has produced a large bycatch of sharks. The resulting enhanced survival of grey seals is reflected in greater infestation of commercially important fish species by the codworm (Phocanema decipiens).Key words: grey seals, harbour seals, sharks, swordfish, codworm, predation, fisheries

The eastern horseshoe bat, Rhinolophus megaphyllus, in south-east Queensland, Australia: colony demography and dynamics, activity levels, seasonal weight changes, and capture-recapture analyses

2001 ◽  
Vol 28 (4) ◽  
pp. 425 ◽  
Author(s):  
R. A. Young
Keyword(s):  
Population Size ◽  
Colony Size ◽  
Activity Levels ◽  
Adult Males ◽  
Weight Changes ◽  
Adult Females ◽  
Colony Demography ◽  
Capture Recapture ◽  
Horseshoe Bat ◽  
Size Estimates

During this study, 634 eastern hoseshoe bats, Rhinolophus megaphyllus, were captured at three colonies in south-east Queensland, with most data coming from two colonies (Anjuramba mine and Ravensbourne cave). Colony size, sex ratios, age structure, and colony function varied between colonies and with season. Capture–recapture data of banded bats was used to monitor movement patterns, seasonal weight changes, colony-size estimates at Anjuramba (JOLLY model), and the recapture frequency according to sex and age. The JOLLY estimator of the population size over-estimated the actual population at Anjuramba on most occasions but paralleled changes in population size. Of the 319 bats banded, 21.9% were recaptured, with only one recovery involving a movement between roosts. Adult males have a high roost-site fidelity and are more sedentary than adult females. The recapture rate and recapture frequency for adult males was significantly higher than for adult females. R. megaphyllus is active throughout the year but may enter torpor for short periods, with more females than males observed in torpor. There was no significant association between torpor and season. Longevity records of 7 years and 1 month were recorded for a sub-adult female and 7 years and 7 months for a juvenile female.

Obsevations on the behaviour of the european rabbit flea, Spilopsullus cuniculi (Dale), ona natural population of wild rabbits, Oryctolagus cuniculus (L.), in Australia

1971 ◽  
Vol 19 (1) ◽  
pp. 41 ◽  
Author(s):  
RT Williams
Keyword(s):  
Population Size ◽  
Natural Population ◽  
Oryctolagus Cuniculus ◽  
European Rabbit ◽  
Control Group ◽  
Rabbit Population ◽  
Group A

The behaviour of S, cuniculi was studied on a natural rabbit population present on an island in Lake Bathurst, N.S.W. Four individually marked groups of fleas and an unmarked control group, a total of 454 in all, were released onto five rabbits trapped at one location. Surveys of the rabbits and their fleas were carried out during the first, second, eighth, and fourteenth weeks after the fleas were released. Rabbit breeding before the fourteenth week resulted in an increase, due to breeding, in the number of unmarked fleas recovered at that time. During weeks one, two, and eight, 316 rabbits, equivalent to three times the estimated population size, were examined for fleas, and only 77 were recovered. Of these, 64 (88 %) were found on rabbits trapped within 25 yd of the point at which they were released. Nine rabbits resident in this area accounted for 52 of these 64 fleas, and there were frequent changes in the degree and composition of the infestations of these rabbits. Two rabbits upon which fleas had been released had lost 94 and 96 % of their fleas within 10 days. It is suggested that these results indicate that many fleas were living freely within the rabbit burrows in the immediate area in which they were released.

scholarly journals Enhancing Solar Still Performance Using Vacuum Pump and Geothermal Energy

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 539
Author(s):  
Syed Danish ◽  
Abdelrahman El-Leathy ◽  
Mohanad Alata ◽  
Hany Al-Ansary
Keyword(s):  
Heat Exchanger ◽  
Wind Speed ◽  
Ambient Temperature ◽  
Water Temperature ◽  
Analytical Model ◽  
Vacuum Pump ◽  
Vacuum Pressure ◽  
Geothermal System ◽  
Outlet Temperature ◽  
Solar Still

Improvement in the performance of a solar still is investigated with the integration of a geothermal cooling system and a vacuum pump. Geothermal cooling is simulated to provide a cold, effective underground water temperature, which could reach 15–25 °C below ambient. Cooling is achieved by circulating water underground. As a result of this circulation, the cold fluid from the ground flows into a counter flow shell and tube heat exchanger. A vacuum pump is used to keep the solar still at a certain vacuum pressure. The sizes of the geothermal system and solar still are designed in such a way that the water outlet temperature from the ground and its flow rate are capable of condensing the entire vapor produced by the still. An analytical model was developed and then solved using the Newton–Raphson method for solving non-linear equations. A prototype was built to validate the analytical model. The results were in close agreement. A 305% increase in daily water productivity resulted from the proposed enhancements. After experimental validation, the effects of various parameters such as vacuum pressure, ambient temperature, and wind speed on the yield of geothermal solar still were examined. It was found that the increase in vacuum pressure enhanced performance, whereas the increase in wind speed had a detrimental effect on the yield of the solar still. A higher ambient temperature increased the yield of the solar still. Finally, the design of the heat exchanger for condensing the distilled water using geothermal cooling water was also investigated in terms of the increase in UA (the product of overall heat transfer coefficient and the area of heat exchanger) with inlet cooling geothermal water temperature.

Roman History

2014 ◽  
Vol 61 (1) ◽  
pp. 129-133
Author(s):  
B. M. Levick
Keyword(s):  
Population Size ◽  
Roman History ◽  
Demographic Parameters ◽  
Roman Economy ◽  
Turn On ◽  
The Past ◽  
The Subject ◽  
Ecological Parameters ◽  
Roman Italy ◽  
And Migration

A quality not much considered here in the past, how often a work is likely be taken from the shelf, prompts me to put Saskia's Hin'sThe Demography of Roman Italyin first position. For that depends in turn on how reliable, clear, and broad of outlook the chapters are, and where they lead the reader. Though dry and plain it might seem (for all the developing technologies), the subject moves directly towards a hot, polarized topic – ‘the Roman economy’ and its development – with oscillation between extreme positions. It is a particular merit, then, to put forward a fresh view (though previously adumbrated elsewhere) that is not extreme and must be taken seriously. That is where Hin will take historians. But the book is structured in three sections: economic and ecological parameters, demographic parameters (morality, fertility, and migration), and population size. The separate chapters are well supported from a variety of evidence, judiciously treated and well written up. That on climate, with a mildly positive conclusion, needed no apology. If I have a complaint is it about the index: dive into a passage involving ‘Brass modelling’ and you will have to rummage back in the text (111) for hope of identifying it.

Experimental Investigation and Numerical Simulation for High Temperature Air Source Heat Pump with New Mixed-Refrigerant

2014 ◽  
Vol 541-542 ◽  
pp. 752-755
Author(s):  
Jun Yang ◽  
Guo Zhong Ding ◽  
Xiao Yan Zhang ◽  
Shui Ming Shu ◽  
Jun Yi Tan
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
High Temperature ◽  
Ambient Temperature ◽  
Water Temperature ◽  
Heat Pump ◽  
Air Source Heat Pump ◽  
Discharge Temperature ◽  
Heating Capacity ◽  
Theory And Experiments

Studies on air source heat pump (ASHP) transfer to high temperature, the performance of air source heat pump greatly depends on the ambient temperature. Aimed at the prototype aeroplane of high temperature air source heat pump, New mixed-refrigerant M-R was adopted, and a simulation was made under a standard conditions with Aspen Plus software. And the results was validated by the experiments. The results showed that a well trend between theory and experiments. In addition, experimental investigation of high temperature air source heat pump were carried out at different conditions. The COP was 1.15, the discharge temperature of compressor was 108.6°Cwhen the outlet water temperature was 85.1°C. The heating capacity is superior. This achieved a leading level at home and abroad.

SEARCHING BEHAVIOUR OF ADULT FEMALE COCCINELLIDAE (COLEOPTERA) ON STEM AND LEAF MODELS

1994 ◽  
Vol 126 (2) ◽  
pp. 389-399 ◽  
Author(s):  
B.D. Frazer ◽  
R.R. McGregor
Keyword(s):  
Ambient Temperature ◽  
Adult Female ◽  
Side Branch ◽  
Searching Behaviour ◽  
Adult Females ◽  
Branching Patterns ◽  
Wooden Dowel ◽  
The Individual ◽  
Species Specific

AbstractBehaviour of locally occurring adult females of seven species of coccinellids was assessed on wooden dowel and paper models that mimicked branching patterns and arrangements of leaf attachments to stems. Ambient temperature and hunger of the beetles were controlled. The movements up or down the main branch of the branch models when contacted from a side branch, duration of searching, and method of leaving leaf models were recorded for 20 beetles of each species.Each species responded to the seven models with different frequencies of behaviours that reflected species-specific modifications of the taxes that lead coccinellids to the tops and terminal parts of plants. Some beetles consistently modified the pattern of responses on die models that was displayed by die species as a whole. The individual modifications could be selected for. The differences in frequencies of behaviours were judged to be sufficient to result in differences in the efficiency with which plants with different architectures were searched.

scholarly journals Investigating the link between Nephrops norvegicus burrow density and sediment composition in Scottish waters

2009 ◽  
Vol 66 (9) ◽  
pp. 2052-2059 ◽  
Author(s):  
Neil Campbell ◽  
Lynda Allan ◽  
Adrian Weetman ◽  
Helen Dobby
Keyword(s):  
Population Size ◽  
Survey Method ◽  
Commercial Fishing ◽  
Sediment Composition ◽  
Nephrops Norvegicus ◽  
Burrow Density ◽  
The North ◽  
Emergence Patterns ◽  
Underwater Television ◽  
Muddy Sediments

Abstract Campbell, N., Allan, L., Weetman, A., and Dobby, H. 2009. Investigating the link between Nephrops norvegicus burrow density and sediment composition in Scottish waters. – ICES Journal of Marine Science, 66: 2052–2059. Nephrops norvegicus is a burrowing decapod, found in the North Atlantic and Mediterranean Sea at depths of 10–1200 m, and currently the most valuable species taken by the commercial fishing industry in Scotland. It constructs and inhabits extensive burrow complexes in suitable muddy sediments. Owing to its variable emergence patterns, catch rates from traditional trawl surveys are not considered a good indicator of population size. Nephrops populations around Scotland are assessed using an underwater television (UWTV) survey method. Sediment samples are collected at the end of each UWTV deployment. This study focuses on two areas off the coast of Scotland and investigates the accuracy of the sediment maps used for assessment purposes, and the relationship between Nephrops burrow density and sediment composition, over the period 2002–2007. Nephrops have a stock-specific relationship with the sediment they inhabit, which retains the same form through fluctuations in population size.

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