523 research outputs found
Combined Effects Of Body Size Food Concentration And Season On Physiology Of Mytilus-Edulis
Multivariate experiments are used to study the effects of body size, food concentration,
and season on the oxygen consumption, ammonia excretion, food assimilation efficiency
and filtration rate of Mytilus edulis adults. Food concentrations and season affect both the
intercept and the slope of the allometric equation describing oxygen uptake as a function
of body size. Multiple regression and response surface techniques are used to describe and
illustrate the complex relationship between metabolic rate, ration, season and the body
size of M. edulis. Filtration rate has a relatively low weight exponent Q> = 038) and the
intercept for the allometric equation is not significantly affected by food concentration,
season or acclimation temperatures between 5 and 20 °C. Food assimilation efficiency
declines exponentially with increasing food concentration and is dependent on body size
at high food levels. The rate of ammonia excretion shows a similar seasonal cycle to that
of oxygen consumption. They are both minimal in the autumn/winter and reach a
maximum in the spring /summer
Physiological Indexes Of Stress In Mytilus-Edulis
Multiple regression equations and response surfaces are used to describe the combined
effects of body size, food concentration, acclimation temperature and season on physiological
integrations such as the scope for growth, growth efficiency and O:N ratio.
Maintenance and optimum ration levels are estimated for Mytilus edulis adapted to
different factor combinations. Response surfaces illustrate the validity and sensitivity of
the physiological integrations in quantifying the 'physiological condition' and the
degree of stress experienced, under conditions ranging from near-optimal, through
sub-lethal to lethal
The ethics of biobanking: key issues and controversies
The ethics of biobanking is one of the most controversial issues in current bioethics and public health debates. For some, biobanks offer the possibility of unprecedented advances which will revolutionise research and improve the health of future generations. For others they are worrying repositories of personal information and tissue which will be used without sufficient respect for those from whom they came. Wherever one stands on this spectrum, from an ethics perspective biobanks are revolutionary. Traditional ethical safeguards of informed consent and confidentiality, for example, simply don’t work for the governance of biobanks and as a result new ethical structures are required. Thus it is not too great a claim to say that biobanks require a rethinking of our ethical assumptions and frameworks which we have applied generally to other issues in ethics. This paper maps the key challenges and controversies of biobanking ethics; it considers; informed consent (its problems in biobanking and possibilities of participants’ withdrawal), broad consent, the problems of confidentiality, ownership, property and comercialisation issues, feedback to participants and the ethics of re-contact
Tidal migration of nematodes on an estuarine tidal flat (the Molenplaat, Schelde Estuary, SW Netherlands)
The vertical distribution patterns of the nematode community and of the 10 most dominant nematode species on an intertidal flat in the Schelde Estuary (the Molenplaat, The Netherlands) are described at specific time intervals over a tidal cycle. The observed distribution profiles indicate that vertical migrations occur and are species-specific. The predatory Enoploides longispiculosus and the deposit-feeding Daptonema normandicum migrated upwards at incoming tide and downwards when the flat became exposed, while another deposit feeder,Daptonema setosum, did the opposite. Several abiotic and biotic factors may contribute to the observed patterns. Hydrodynamics, pore water drainage and episodic steep increases in temperature upon low tide exposure as well as vertical movements of prey organisms may have been of particular relevance at the time and site of sampling. However, the impact of each of these factors needs further investigation. The present study corroborates the dynamic nature of vertical distribution profiles of nematodes in intertidal sediments, highlighting the importance of sampling time with respect to the tide, as well as a species approach
Concepts and Their Dynamics: A Quantum-Theoretic Modeling of Human Thought
We analyze different aspects of our quantum modeling approach of human
concepts, and more specifically focus on the quantum effects of contextuality,
interference, entanglement and emergence, illustrating how each of them makes
its appearance in specific situations of the dynamics of human concepts and
their combinations. We point out the relation of our approach, which is based
on an ontology of a concept as an entity in a state changing under influence of
a context, with the main traditional concept theories, i.e. prototype theory,
exemplar theory and theory theory. We ponder about the question why quantum
theory performs so well in its modeling of human concepts, and shed light on
this question by analyzing the role of complex amplitudes, showing how they
allow to describe interference in the statistics of measurement outcomes, while
in the traditional theories statistics of outcomes originates in classical
probability weights, without the possibility of interference. The relevance of
complex numbers, the appearance of entanglement, and the role of Fock space in
explaining contextual emergence, all as unique features of the quantum
modeling, are explicitly revealed in this paper by analyzing human concepts and
their dynamics.Comment: 31 pages, 5 figure
Pre-ingestive selection capacity and endoscopic analysis in the sympatric bivalves Mulinia edulis and Mytilus chilensis exposed to diets containing toxic and non-toxic dinoflagellates
This study investigates the effects of toxic and non-toxic dinoflatellates on two sympatric bivalves, the clam Mulinia edulis and the mussel Mytilus chilensis. Groups of bivalves were fed one of three diets: (i) the toxic paralytic shellfish producing (PSP) Alexandrium catenella + Isochrysis galbana; (ii) the non-toxic Alexandrium affine + Isochrysis galbana and (iii) the control diet of Isochrysis galbana. Several physiological traits were measured, such as, clearance rate, pre-ingestive selection efficiency and particle transport velocity in the gill. The clearance rates of both M. chilensis and M. edulis showed a significant reduction when fed a mixed toxic diet of 50% Alexandrium catenella: 50% Isochrysis galbana. Similarly, when both species of bivalves were fed with the non-toxic diet (50% A. affine: 50% I. galbana), clearance rate was significantly lower compared with a diet of 100% I. galbana. Under all the experimental diets, M. chilensis showed higher clearance rate values, slightly more than double that of M. edulis. M. edulis and M. chilensis have the ability to select particles at the pre-ingestive level, thus eliminating a larger proportion of the toxic dinoflagellate A. catenella as well as the non-toxic A. affine in the form of pseudofaeces. Higher values of selection efficiency were registered in M. edulis than in M. chilensis when exposed to the toxic diet. Similar results were observed when these two species were exposed to the diet containing the non-toxic dinoflagellate, explained by the fact that the infaunal Mulinia edulis is adapted to dealing with larger particle sizes and higher particle densities (Navarro et al., 1993). The lower transport particle velocity observed in the present work for both species, is related to the reduced clearance rate, the higher particle concentration, and the presence of larger, toxic dinoflagellates. In addition, the species differ in their feeding responses to diets, with and without A. catenella or A. affine, largely reflecting their adaptations to different environmental conditions. The results suggest that the presence of a dinoflagellate bloom, whether toxic or non-toxic spp in Yaldad Bay, is likely to have a greater impact on the Mytilus chilensis than the infaunal Mulinia edulis, based on the combined effects on clearance rate, selection efficiency and particle transport velocity
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Quantum circuit components for cognitive decision-making
This paper demonstrates that some non-classical models of human decision-making can be run successfully as circuits on quantum computers. Since the 1960s, many observed cognitive behaviors have been shown to violate rules based on classical probability and set theory. For example, the order in which questions are posed in a survey affects whether participants answer ‘yes’ or ‘no’, so the population that answers ‘yes’ to both questions cannot be modeled as the intersection of two fixed sets. It can, however, be modeled as a sequence of projections carried out in different orders. This and other examples have been described successfully using quantum probability, which relies on comparing angles between subspaces rather than volumes between subsets. Now in the early 2020s, quantum computers have reached the point where some of these quantum cognitive models can be implemented and investigated on quantum hardware, by representing the mental states in qubit registers, and the cognitive operations and decisions using different gates and measurements. This paper develops such quantum circuit representations for quantum cognitive models, focusing particularly on modeling order effects and decision-making under uncertainty. The claim is not that the human brain uses qubits and quantum circuits explicitly (just like the use of Boolean set theory does not require the brain to be using classical bits), but that the mathematics shared between quantum cognition and quantum computing motivates the exploration of quantum computers for cognition modeling. Key quantum properties include superposition, entanglement, and collapse, as these mathematical elements provide a common language between cognitive models, quantum hardware, and circuit implementations
Potentials for hyper-Kahler metrics with torsion
We prove that locally any hyper-K\"ahler metric with torsion admits an HKT
potential.Comment: 9 page
Quantum Particles as Conceptual Entities: A Possible Explanatory Framework for Quantum Theory
We put forward a possible new interpretation and explanatory framework for
quantum theory. The basic hypothesis underlying this new framework is that
quantum particles are conceptual entities. More concretely, we propose that
quantum particles interact with ordinary matter, nuclei, atoms, molecules,
macroscopic material entities, measuring apparatuses, ..., in a similar way to
how human concepts interact with memory structures, human minds or artificial
memories. We analyze the most characteristic aspects of quantum theory, i.e.
entanglement and non-locality, interference and superposition, identity and
individuality in the light of this new interpretation, and we put forward a
specific explanation and understanding of these aspects. The basic hypothesis
of our framework gives rise in a natural way to a Heisenberg uncertainty
principle which introduces an understanding of the general situation of 'the
one and the many' in quantum physics. A specific view on macro and micro
different from the common one follows from the basic hypothesis and leads to an
analysis of Schrodinger's Cat paradox and the measurement problem different
from the existing ones. We reflect about the influence of this new quantum
interpretation and explanatory framework on the global nature and evolutionary
aspects of the world and human worldviews, and point out potential explanations
for specific situations, such as the generation problem in particle physics,
the confinement of quarks and the existence of dark matter.Comment: 45 pages, 10 figure
Quantum Aspects of Semantic Analysis and Symbolic Artificial Intelligence
Modern approaches to semanic analysis if reformulated as Hilbert-space
problems reveal formal structures known from quantum mechanics. Similar
situation is found in distributed representations of cognitive structures
developed for the purposes of neural networks. We take a closer look at
similarites and differences between the above two fields and quantum
information theory.Comment: version accepted in J. Phys. A (Letter to the Editor
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