Tychobythinus antojandro sp. nov., a new troglobitic species of Pselaphinae (Coleoptera: Staphylinidae) from Andalusia, Spain.

A new troglobitic species of the subfamily Pselaphinae (Coleoptera: Staphylinidae), Tychobythinus antojandro sp. nov., is described from a cave in south Spain.

Analysing human mobility patterns of hiking activities through complex network theory.

The exploitation of high volume of geolocalized data from social sport tracking applications of outdoor activities can be useful for natural resource planning and to understand the human mobility patterns during leisure activities. This geolocalized data represents the selection of hike activities according to subjective and objective factors such as personal goals, personal abilities, trail conditions or weather conditions. In our approach, human mobility patterns are analysed from trajectories which are generated by hikers.

Collective Intelligence: Aggregation of Information from Neighbors in a Guessing Game.

Complex systems show the capacity to aggregate information and to display coordinated activity. In the case of social systems the interaction of different individuals leads to the emergence of norms, trends in political positions, opinions, cultural traits, and even scientific progress. Examples of collective behavior can be observed in activities like the Wikipedia and Linux, where individuals aggregate their knowledge for the benefit of the community, and citizen science, where the potential of collectives to solve complex problems is exploited.

Competition in the presence of aging: dominance, coexistence, and alternation between states.

We study the stochastic dynamics of coupled states with transition probabilities depending on local persistence, this is, the time since a state has changed. When the system has a preference to adopt older states the system orders quickly due to the dominance of old states. When preference for new states prevails, the system can show coexistence of states or synchronized collective behavior resulting in long ordering times.

Self assembly of Janus ellipsoids.

We propose a primitive model of Janus ellipsoids that represents particles with an ellipsoidal core and two semisurfaces coded with dissimilar properties, for example, hydrophobicity and hydrophilicity, respectively. We investigate the effects of the aspect ratio on the self-assembly morphology and aggregation processes using Monte Carlo simulations. We also discuss certain differences between our results and those of earlier results for Janus spheres.

Kinetics of nanochain formation in a simplified model of amelogenin biomacromolecules.

We show that the kinetics of nanochain formation of amelogenin molecules is well described by a combination of translational and rotational diffusion of a simplified anisotropic bipolar model consisting of hydrophobic spherical colloid particles and a point charge located on each particle surface. The colloid particles interact via a standard depletion attraction whereas the point charges interact through a screened Coulomb repulsion. We study the kinetics via a Brownian dynamics simulation of both translational and rotational motions and show that the anisotropy brought in by the charge dramatically affects the kinetic pathway of cluster formation and our simple model captures the main features of the experimental observations.

Pathways of cluster growth and kinetic slowing down in a model of short-range attractive colloids.

We present the results of an extensive 3D Brownian dynamics simulation of the self-assembly of colloidal particles for a short-range attractive model that is quenched below its metastable critical point. In particular, results are obtained in the small-volume-fraction, low-temperature region in which we find so-called sticky beads that diffuse around the system, without reaching a final large cluster on the timescale of our simulation. For larger volume fractions in this low-temperature regime, a gel forms as the result of kinetically slowed down spinodal decomposition, as shown earlier for other short-range attractive models (Foffi, G.

Reliability and synchronization in a delay-coupled neuronal network with synaptic plasticity.

We investigate the characteristics of reliability and synchronization of a neuronal network of delay-coupled integrate and fire neurons. Reliability and synchronization appear in separated regions of the phase space of the parameters considered. The effect of including synaptic plasticity and different delay values between the connections are also considered.

Structural and functional networks in complex systems with delay.

Functional networks of complex systems are obtained from the analysis of the temporal activity of their components, and are often used to infer their unknown underlying connectivity. We obtain the equations relating topology and function in a system of diffusively delay-coupled elements in complex networks. We solve exactly the resulting equations in motifs (directed structures of three nodes) and in directed networks.

Phase clustering in complex networks of delay-coupled oscillators.

We study the clusterization of phase oscillators coupled with delay in complex networks. For the case of diffusive oscillators, we formulate the equations relating the topology of the network and the phases and frequencies of the oscillators (functional response). We solve them exactly in directed networks for the case of perfect synchronization.

Effect of the topology and delayed interactions in neuronal networks synchronization.

As important as the intrinsic properties of an individual nervous cell stands the network of neurons in which it is embedded and by virtue of which it acquires great part of its responsiveness and functionality. In this study we have explored how the topological properties and conduction delays of several classes of neural networks affect the capacity of their constituent cells to establish well-defined temporal relations among firing of their action potentials. This ability of a population of neurons to produce and maintain a millisecond-precise coordinated firing (either evoked by external stimuli or internally generated) is central to neural codes exploiting precise spike timing for the representation and communication of information.

Statistical mechanics of helical wormlike chain model.

We investigate the statistical mechanics of polymers with bending and torsional elasticity described by the helical wormlike model. Noticing that the energy function is factorizable, we provide a numerical method to solve the model using a transfer matrix formulation. The tangent-tangent and binormal-binormal correlation functions have been calculated and displayed rich profiles which are sensitive to the combination of the temperature and the equilibrium torsion.

The constructive role of diversity in the global response of coupled neuron systems.

We study the effect that the heterogeneity present among the elements of an ensemble of coupled excitable neurons has on the collective response of the system to an external signal. We consider two different interaction scenarios, one in which the neurons are diffusively coupled and another in which the neurons interact via pulse-like signals. We find that the type of interaction between the neurons has a crucial role in determining the response of the system to the external modulation.

An intersegmental neuronal architecture for spinal wave propagation under deletions.

Recent studies have established and characterized the propagation of traveling electrical waves along the cat spinal cord during scratching, but the neuronal architecture that allows for the persistence of such waves even during periods of absence of bursts of motoneuron activity (deletions) is still unclear. Here we address this problem both theoretically and experimentally. Specifically, we monitored during long lasting periods of time the global electrical activity of spinal neurons during scratching.

Bistability and all-optical switching in semiconductor ring lasers.

Semiconductor ring lasers display a variety of dynamical regimes originating from the nonlinear competition between the clockwise and counter-clockwise propagating modes. In particular, for large pumping the system has a bistable regime in which two stationary quasi-unidirectional counter-propagating modes coexist. Bistability is induced by cross-gain saturation of the two counter-propagating modes being stronger than the self-saturation and can be used for data storage when the semiconductor ring laser is addressed with an optical pulse.

Stochastic resonance in the motor system: effects of noise on the monosynaptic reflex pathway of the cat spinal cord.

In sensory systems, the presence of a particular nonzero level of noise may significantly enhance the ability of an individual to detect weak sensory stimuli through a phenomenon known as stochastic resonance (SR). The aim of this study was to demonstrate if such phenomenon is also exhibited by the motor system; in particular, in the Ia-motoneuron synapse of the cat spinal cord. Monosynaptic reflexes elicited by periodic electrical stimulation to the medial gastrocnemius nerve were recorded in the L(7) ventral root (or in single motoneurons) of decerebrated cats.