331 research outputs found
Density functional theory for strongly-correlated bosonic and fermionic ultracold dipolar and ionic gases
We introduce a density functional formalism to study the ground-state
properties of strongly-correlated dipolar and ionic ultracold bosonic and
fermionic gases, based on the self-consistent combination of the weak and the
strong coupling limits. Contrary to conventional density functional approaches,
our formalism does not require a previous calculation of the interacting
homogeneous gas, and it is thus very suitable to treat systems with tunable
long-range interactions. Due to its asymptotic exactness in the regime of
strong correlation, the formalism works for systems in which standard
mean-field theories fail.Comment: 5 pages, 2 figure
An ethical matrix for the reintroduction of trafficked primates:a platyrrhine case study
The illegal primate trade is one of the major drivers of the decline of nonhuman primate populations and a threat to their wellbeing. Thousands of trafficked primates enter rescue centers every year, and their destiny (release back into the wild, long-term captivity, or euthanasia) involves controversial decisions and complex ethical considerations. To navigate these issues, we developed an ethical matrix, an ethical framework previously used to address conservation-related issues. We gathered information from studies on the reintroduction of trafficked platyrrhines in Latin America from 1990 to 2022 to develop the matrix. We found 22 studies performed in eight Latin American countries, which included howler monkeys, spider monkeys, woolly monkeys, capuchin monkeys, squirrel monkeys, marmosets, and tamarins. We found that the reintroduction of trafficked platyrrhines may yield positive results for the welfare of individuals and for the conservation of their taxa and some of the potential negative effects, such as spillover of infectious agents to free-ranging populations or to human populations, or competition for resources between reintroduced monkeys and resident conspecifics have not yet been documented in the scientific literature, although this does not mean that they do not occur. We conclude that the ethical matrix is a useful method to consider the interests of all potential stakeholders and that the reintroduction of trafficked primates may be a viable management option if the individual welfare of the animals is considered, programs comply with the IUCN and government guidelines, and the objective and justification of the reintroduction are clear
A Screen-Peck Task for Investigating Cognitive Bias in Laying Hens
Affect-induced cognitive judgement biases occur in both humans and animals. Animals in a more negative affective state tend to interpret ambiguous cues more negatively than animals in a more positive state and vice versa. Investigating animals' responses to ambiguous cues can therefore be used as a proxy measure of affective state. We investigated laying hens' responses to ambiguous stimuli using a novel cognitive bias task. In the 'screen-peck' task, hens were trained to peck a high/low saturation orange circle presented on a computer screen (positive cue-P) to obtain a mealworm reward, and to not peck when the oppositely saturated orange circle was presented (negative cue-N) to avoid a one second air puff. Ambiguous cues were orange circles of intermediate saturation between the P and N cue (near-positive-NP; middle-M; near-negative-NN), and were unrewarded. Cue pecking showed a clear generalisation curve from P through NP, M, NN to N suggesting that hens were able to associate colour saturation with reward or punishment, and could discriminate between stimuli that were more or less similar to learnt cues. Across six test sessions, there was no evidence for extinction of pecking responses to ambiguous cues. We manipulated affective state by changing temperature during testing to either ~20°C or ~29°C in a repeated measures cross-over design. Hens have been shown to prefer temperatures in the higher range and hence we assumed that exposure to the higher temperature would induce a relatively positive affective state. Hens tested under warmer conditions were significantly more likely to peck the M probe than those tested at cooler temperatures suggesting that increased temperature in the ranges tested here may have some positive effect on hens, inducing a positive cognitive bias
Quantum-Informed Recursive Optimization Algorithms
We propose and implement a family of quantum-informed recursive optimization
(QIRO) algorithms for combinatorial optimization problems. Our approach
leverages quantum resources to obtain information that is used in
problem-specific classical reduction steps that recursively simplify the
problem. These reduction steps address the limitations of the quantum component
and ensure solution feasibility in constrained optimization problems.
Additionally, we use backtracking techniques to further improve the performance
of the algorithm without increasing the requirements on the quantum hardware.
We demonstrate the capabilities of our approach by informing QIRO with
correlations from classical simulations of shallow (depth ) circuits of
the quantum approximate optimization algorithm (QAOA), solving instances of
maximum independent set and maximum satisfiability problems with hundreds of
variables. We also demonstrate how QIRO can be deployed on a neutral atom
quantum processor available online on Amazon Braket to find large independent
sets of graphs. In summary, our scheme achieves results comparable to classical
heuristics, such as simulated annealing and greedy algorithms, even with
relatively weak quantum resources. Furthermore, enhancing the quality of these
quantum resources improves the performance of the algorithms, highlighting the
potential of QIRO. Notably, the modular nature of QIRO offers various avenues
for modifications, positioning our work as a blueprint for designing a broader
class of hybrid quantum-classical algorithms for combinatorial optimization.Comment: 17 pages, 10 figures. Revised Figs. 1 and
Routine handling methods affect behaviour of three-spined sticklebacks in a novel test of anxiety
Fish are increasingly popular subjects in behavioural and neurobiological research. It is therefore important that they are housed and handled appropriately to ensure good welfare and reliable scientific findings, and that species-appropriate behavioural tests (e.g. of cognitive/affective states) are developed. Routine handling of captive animals may cause physiological stress responses that lead to anxiety-like states (e.g. increased perception of danger). In fish, these may be particularly pronounced when handling during tank-to-tank transfer involves removal from water into air. Here we develop and use a new combined scototaxis (preference for dark over light areas) and novel-tank-diving test, alongside conventional open-field and novel-object tests, to measure the effects of transferring three-spined sticklebacks (Gasterosteus aculeatus) between tanks using a box or net (in and out of water respectively). Preference tests for dark over light areas confirmed the presence of scototaxis in this species. Open-field and novel-object tests failed to detect any significant differences between net and box-handled fish. However, the combined diving and scototaxis detected consistent differences between the treatments. Net-handled fish spent less time on the dark side of the tank, less time in the bottom third, and kept a greater distance from the ‘safe’ bottom dark area than box-handled fish. Possible explanations for this reduction in anxiety-like behaviour in net-handled fish are discussed. The combined diving and scototaxis test may be a sensitive and taxon-appropriate method for measuring anxiety-like states in fish
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