A neural mechanism for binaural pitch perception via ghost stochastic resonance

We present a physiologically plausible binaural mechanism for the perception of the pitch of complex sounds via ghost stochastic resonance. In this scheme, two neurons are driven by noise and different periodic signal each (with frequencies f1=kf0 and f2=(k+1)f0, where k>1), and their outputs (plus noise) are applied synaptically to a third neuron. Our numerical results, using the Morris-Lecar neuron model with chemical synapses explicity considered, show that intermediate noise levels enhance the response of the third neuron at frequencies close to f0, as in the cases previously described of ghost resonance. For the case of inharmonic combinations of inputs (both frequencies shifted by the same amount Df) noise is also seen to enhance the response of the third neuron at a frequency fr with also shift linearly with Df. In addition, we show that similar resonances can be observed as a function of the synaptic time constant. The suggested ghost-resonance-based stochastic mechanism can thus arise either at the peripheral level or at a higher level of neural processing in the perception of the pitchComment: 7 pages, 5 figure

Strategies for creating new informational primitives in minds and machines

Open-endedness is an important goal for designing systems that can autonomously find new and expected solutions to combinatorically-complex and ill-defined problems. Classically, issues of open-ended generation of novelty in the universe have come under the rubric of the problem of emergence. We distinguish two modes of creating novelty: combinatoric (new combinations of existing primitive

Notes on the demonstration of the formation of a new "symbol"

This is a writeup of our group project, which was to demonstrate by means of a game, how two human actors can come to agreement on the semantic meanings of an arbitrary set of signs

Monitoring of common sole Solea Solea (L) captive broodstock from Northern Adriatic Sea over consecutive spawning seasons

The high nutritional quality of common sole Solea solea increases its value for the fishery industry and for the aquaculture sector. To ensure the expansion of its production, it is necessary to implement farming and broodstock management technique to produce high quality eggs and larvae. This work summarizes eight years of study on reproductive performances, growth and parental contribution of a common sole broodstock from the Mediterranean-North Adriatic Sea. The broodstock (11 females and 13 males) reached the peak of fecundity after 5/6 years of captivity, with a production of 296,476 and 376,541 7 103 of total eggs kg 121 female with a fertilization rate of 31.6 \ub1 18.3 and 41.9 \ub1 23.8 %, respectively. Results shows that variations in temperature cycles are pivotal for a successful breeding season, and body condition during the first 3 years of captivity was the most important parameter positively correlated to parental contribution for both males and females. Parental contribution was assessed by eight species-specific microsatellite loci during the first 3 years of reproduction. Although the two sexes displayed different temporal trends, parentage assessment demonstrated an overall increase in the number of active breeders. However, only 13 couples out of 50 produced the 70.4 % of the larvae in year 5, confirming the same reproduction behavioural pattern in Mediterranean common sole than that observed both in Senegalese sole and in common sole of Atlantic origin. This work provides valuable data needed to understand the mechanisms behind the maturation characteristics of this species and support future strategy for the establishment and management of Mediterranean common sole aquaculture

DNA metabarcoding of trawling bycatch reveals diversity and distribution patterns of sharks and rays in the central Tyrrhenian Sea

Conservation and management of chondrichthyans are becoming increasingly important, as many species are particularly vulnerable to fishing activities, primarily as bycatch, which leads to incomplete catch reporting, potentially hiding the impact on these organisms. Here, we aimed at implementing an eDNA metabarcoding approach to reconstruct shark and ray bycatch composition from 24 hauls of a bottom trawl fishing vessel in the central Mediterranean. eDNA samples were collected through the passive filtration of seawater by simple gauze rolls encapsulated in a probe (the "metaprobe"), which already showed great efficiency in detecting marine species from trace DNA in the environment. To improve molecular taxonomic detection, we enhanced the 12S target marker reference library by generating sequences for 14 Mediterranean chondrichthyans previously unrepresented in public repositories. DNA metabarcoding data correctly identifies almost all bycaught species and detected five additional species not present in the net, highlighting the potential of this method to detect rare species. Chondrichthyan diversity showed significant association with some key environmental variables (depth and distance from the coast) and the fishing effort, which are known to influence demersal communities. As DNA metabarcoding progressively positions itself as a staple tool for biodiversity monitoring, we expect that its melding with opportunistic, fishery-dependent surveys could reveal additional distribution features of threatened and elusive megafauna

Self-repair ability of evolved self-assembling systems in cellular automata

Self-repairing systems are those that are able to reconfigure themselves following disruptions to bring them back into a defined normal state. In this paper we explore the self-repair ability of some cellular automata-like systems, which differ from classical cellular automata by the introduction of a local diffusion process inspired by chemical signalling processes in biological development. The update rules in these systems are evolved using genetic programming to self-assemble towards a target pattern. In particular, we demonstrate that once the update rules have been evolved for self-assembly, many of those update rules also provide a self-repair ability without any additional evolutionary process aimed specifically at self-repair

Intratumor Regulatory Noncytotoxic NK Cells in Patients with Hepatocellular Carcinoma

Previous studies support the role of natural killer (NK) cells in controlling hepatocellular carcinoma (HCC) progression. However, ambiguity remains about the multiplicity and the role of different NK cell subsets, as a pro-oncogenic function has been suggested. We performed phenotypic and functional characterization of NK cells infiltrating HCC, with the corresponding nontumorous tissue and liver from patients undergoing liver resection for colorectal liver metastasis used as controls. We identified a reduced number of NK cells in tumors with higher frequency of CD56(BRIGHT)CD16(-) NK cells associated with higher expression of NKG2A, NKp44, and NKp30 and downregulation of NKG2D. Liver-resident (CXCR6(+)) NK cells were reduced in the tumors where T-bet(hi)Eomes(lo) expression was predominant. HCCs showed higher expression of CD49a with particular enrichment in CD49a(+)Eomes(+) NK cells, a subset typically represented in the decidua and playing a proangiogenic function. Functional analysis showed reduced TNF-alpha production along with impaired cytotoxic capacity that was inversely related to CXCR6(-), T-bet(hi)Eomes(lo), and CD49a(+)Eomes(+) NK cells. In conclusion, we identified a subset of NK cells infiltrating HCC, including non-liver-resident cells that coexpressed CD49a and Eomes and showed reduced cytotoxic potential. This NK cell subset likely plays a regulatory role in proangiogenic function

The Computational Complexity of Symbolic Dynamics at the Onset of Chaos

In a variety of studies of dynamical systems, the edge of order and chaos has been singled out as a region of complexity. It was suggested by Wolfram, on the basis of qualitative behaviour of cellular automata, that the computational basis for modelling this region is the Universal Turing Machine. In this paper, following a suggestion of Crutchfield, we try to show that the Turing machine model may often be too powerful as a computational model to describe the boundary of order and chaos. In particular we study the region of the first accumulation of period doubling in unimodal and bimodal maps of the interval, from the point of view of language theory. We show that in relation to the ``extended'' Chomsky hierarchy, the relevant computational model in the unimodal case is the nested stack automaton or the related indexed languages, while the bimodal case is modeled by the linear bounded automaton or the related context-sensitive languages.Comment: 1 reference corrected, 1 reference added, minor changes in body of manuscrip

Evaluating genetic traceability methods for captive bred marine fish and their applications in fisheries management and wildlife forensics

Growing demands for marine fish products is leading to increased pressure on already depleted wild populations and a rise in the aquaculture production. Consequently, more captive bred fish are released into the wild through accidental escape or deliberate restocking, stock enhancement and sea ranching programs. The increased mixing of captive bred fish with wild conspecifics may affect the ecological and/or genetic integrity of wild fish populations. From a fisheries management perspective unambiguous identification tools for captive bred fish will be highly valuable to manage risks. Additionally there is great potential to use these tools in wildlife forensics (i.e. tracing back escapees to their origin and determining mislabelling of seafood products). Using SNP data from captive bred and wild populations of Atlantic cod (Gadus morhua L.) and sole (Solea solea L.), we explored the efficiency of population and parentage assignment techniques for the identification and tracing of captive bred fish. Simulated and empirical data were used to correct for stochastic genetic effects. Overall, parentage assignment performed well when a large effective population size characterizes the broodstock and escapees originate from early generations of captive breeding. Consequently, parentage assignments are particularly useful from a fisheries management perspective to monitor the effects of deliberate releases of captive bred fish on wild populations. Population assignment proved to be more efficient after several generations of captive breeding, which makes it a useful method in forensic applications for well-established aquaculture species. We suggest the implementation of a case by case strategy when choosing the best method