The constraints on cephalopods: why squid aren't fish

1986 ◽  
Vol 64 (8) ◽  
pp. 1591-1605 ◽  
Author(s):  
R. K. O'Dor ◽  
D. M. Webber
Keyword(s):  
Convergent Evolution ◽  
High Energy ◽  
Life Cycles ◽  
Metabolic Rates ◽  
Short Life ◽  
Jet Propulsion ◽  
Reproductive Patterns ◽  
Anatomical Basis ◽  
Physiology And Biochemistry ◽  
Physiological And Biochemical

The convergent evolution of cephalopods and fish has often been discussed on an anatomical basis, but recent advances in the knowledge of cephalopod life cycles, physiology, and biochemistry suggest that there are constraints on cephalopods that prevent them from competing directly with fish. These advances are reviewed against the background of detailed information on fish from the perspective that the basic inefficiency of the jet-propulsion system has required bioenergetic, physiological, and biochemical adaptations in squid which maximize their metabolic rates. Such "high-energy" adaptations are suggested to have resulted in the short life history and semelparous reproductive patterns that seem to characterize these coleoid cephalopods. Conversely, the physiology and biochemistry offish give them distinct advantages for long lives and iteroparity.

Organizing a public aquarium: objectives, design, operation and missions. A review

2013 ◽  
Vol 13 (4) ◽  
pp. 369-384
Keyword(s):  
Life Cycles ◽  
Ex Situ ◽  
Responsible Behavior ◽  
Scientific Disciplines ◽  
Public Aquarium ◽  
Physiology And Biochemistry ◽  
Taxonomic Concept ◽  
Conservation Projects ◽  
Surrounding Areas ◽  
Community Concept

Many Public Aquaria have been designed and constructed all over the world during the last three decades. The serial arrangement of relatively small, rectangular, concrete tanks has been replaced by fewer large, irregularly shaped tanks, replicating habitats. The “taxonomic concept” of displaying specimens in the old aquaria has now been succeeded by the more ecological, “community concept” type of display. At the same time most of the “old aquaria” have been renovated. Aquarium missions have also been broadened nowadays including research, conservation and education. Aquaria are ideal places for research on husbandry, life cycles, reproduction, behavior, autoecology and fish pathology. Collaboration with Universities and Research Centers increases the research potential in scientific disciplines such as ecology, genetics, physiology and biochemistry. Collaboration also provides mutual benefits in both infrastructure and personnel: The research background in aquaria also forms a sound platform to materialize conservation projects, focusing either on the ex-situ conservation of animals in the aquaria or on environmental protection of surrounding areas and reintroduction of endangered species. In addition to formal educational opportunities, non formal education to visitors, schools and undergraduates seems to become a major mission of aquaria. Aquarium tank displays, preserved biological material, film projections, seminars / lectures and book magazine publications enhance environmental awareness, encouraging people to adopt Environmentally Responsible Behavior. All these missions are feasible because most public aquaria are making a good profit mainly due to their high popularity. There are also benefits for the community in the area; aquaria have enlivened declining water front areas and increased the income of tourist resorts mainly by “stretching out” the tourist season. In the present work the objectives of a public aquarium are reviewed and the main infrastructure subsystems and operational procedures are described; Know how on aquarium systems can also be applied in research laboratories of academic institutions if live organisms have to be kept for experimentation. Aquarium missions on research, conservation and education are discussed.

Reproduction

2017 ◽  
Author(s):  
Derek Burton ◽  
Margaret Burton
Keyword(s):  
Reproductive Behaviour ◽  
Life Cycles ◽  
Freshwater Species ◽  
Adult Fish ◽  
Reproductive Patterns ◽  
Cell Divisions ◽  
Early Stages ◽  
External Cues ◽  
Neural Factors

Interspecific fish reproductive patterns, outputs and life cycles display the greatest variability within the vertebrates. Early stages of oogenesis can be repeated in adult fish, contrasting with mammals; the pre-set sequence of cell divisions in gametogenesis is otherwise similar and is described in detail. Most fish deposit much yolk (vitellogenesis) in developing eggs. Migrations, beach-spawning and mouth-brooding are some of the interesting variations. Fertilization is predominantly external but is internal in some groups such as chondrichthyans. The omission of annual reproduction is well established in some freshwater species and the idea that this may also be the case for marine teleosts is gaining acceptance. This should be taken into account for intensively fished species. The possible roles of external cues, hormones, pheromones and neural factors acting as ‘switches’ and coordinators in gametogenesis and reproductive behaviour are discussed.

Thermostructural Analyses Supporting the Design of the HYPROB Heat Sink Subscale Breadboard

2014 ◽  
Author(s):  
M. Ferraiuolo ◽  
A. Martucci ◽  
F. Battista ◽  
D. Ricci
Keyword(s):  
Heat Sink ◽  
Structural Integrity ◽  
Specific Impulse ◽  
Thermal Analyses ◽  
High Energy ◽  
Life Cycles ◽  
Heat Fluxes ◽  
Point Of View ◽  
Rocket Engines ◽  
Combustion Enthalpy

Today’s rocket engines regeneratively cooled using high energy cryogenic propellants (e.g. LOX and LH2, LOX and LCH4) play a major role due to the high combustion enthalpy (10–13.4 kJ/kg) and the high specific impulse of these propellants. In the frame of the HYPROB/Bread project, whose main goal is to design build and test a 30 kN regeneratively cooled thrust chamber, a breadboard has been conceived in order to: • investigate the behavior of the injector that will be employed in the full scale final demonstrator, • to obtain a first estimate of the heat flux on the combustion chamber for models validation, • to implement a “battleship” chamber for a first verification of the stability of the combustion The breadboard is called HS (Heat Sink) and it is made of CuCrZr (Copper Chromium Zirconium alloy), Inconel 718 and TZM (Titanium Zirconium Molybdenum alloy). The aim of the present paper is to illustrate the thermostructural design conducted on the breadboard by means of a Finite Element Method code taking into account the viscoplastic behavior of the adopted materials. An optimization process has been carried out in order to keep the structural integrity of the breadboard maximizing the life cycles of the component. Heat fluxes generated by combustion gases have been evaluated by means of CFD quick analyses, while convection and radiation with the external environment have not been considered in order to be as conservative as possible from a thermostructural point of view. Transient thermal analyses and static structural analyses have been performed by means of ANSYS code adopting an axisymmetric model of the chamber. These analyses have demonstrated that the Breadboard can withstand the design goal of 3 thermo-mechanical cycles with a safety factor equal to 4 considering a firing time equal to 3 seconds.

The potential use of environmental information to manage squid stocks

2002 ◽  
Vol 59 (12) ◽  
pp. 1851-1857 ◽  
Author(s):  
D J Agnew ◽  
J R Beddington ◽  
S L Hill
Keyword(s):  
Management Strategy ◽  
Historical Data ◽  
Simulation Models ◽  
Life Cycles ◽  
Sea Surface ◽  
Short Life ◽  
Stock Biomass ◽  
Predictive Relationships ◽  
Potential Use

Most commercially exploited squid species have short life cycles and stocks composed of recruits from a single cohort, the size of which is unknown prior to the fishing season. Recent studies suggest that strong environment–recruitment relationships may exist for a number of squid stocks. Using simulation models based on Falkland Island Patagonian squid (Loligo gahi), the recruit abundance of which is predicted by sea-surface temperature, we propose a method for using predictive relationships in the management of squid populations. We compare a management strategy based on recruitment prediction with historical data from the fishery, which was managed in the absence of these predictions. Our results suggest that varying effort on the basis of an environmental correlate of recruitment can reduce the risk of not meeting conservation targets while increasing yield. Effort has to be reduced in years of low abundance but licensing additional effort in years of high abundance increases long-term average catches. Even if effort levels were not allowed to vary by more than 50% between years, a management strategy for L. gahi based on prediction would have resulted in higher average catches and a reduced probability of the stock biomass falling below a notional conservation limit.

scholarly journals Whole-Tissue Three-Dimensional Imaging of Rice at Single-Cell Resolution

2021 ◽  
Vol 23 (1) ◽  
pp. 40
Author(s):  
Moeko Sato ◽  
Hiroko Akashi ◽  
Yuki Sakamoto ◽  
Sachihiro Matsunaga ◽  
Hiroyuki Tsuji
Keyword(s):  
Three Dimensional ◽  
Root Apical Meristem ◽  
Auxin Signaling ◽  
Quiescent Center ◽  
Root Tips ◽  
Fluorescent Reporters ◽  
Apical Meristems ◽  
Anatomical Basis ◽  
And Function ◽  
Physiological And Biochemical

The three-dimensional (3D) arrangement of cells in tissues provides an anatomical basis for analyzing physiological and biochemical aspects of plant and animal cellular development and function. In this study, we established a protocol for tissue clearing and 3D imaging in rice. Our protocol is based on three improvements: clearing with iTOMEI (clearing solution suitable for plants), developing microscopic conditions in which the Z step is optimized for 3D reconstruction, and optimizing cell-wall staining. Our protocol successfully 3D imaged rice shoot apical meristems, florets, and root apical meristems at cellular resolution throughout whole tissues. Using fluorescent reporters of auxin signaling in rice root tips, we also revealed the 3D distribution of auxin signaling events that are activated in the columella, quiescent center, and multiple rows of cells in the stele of the root apical meristem. Examination of cells with higher levels of auxin signaling revealed that only the central row of cells was connected to the quiescent center. Our method provides opportunities to observe the 3D arrangement of cells in rice tissues.

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