Intrinsic adaptation in autonomous recurrent neural networks

A massively recurrent neural network responds on one side to input stimuli and is autonomously active, on the other side, in the absence of sensory inputs. Stimuli and information processing depends crucially on the qualia of the autonomous-state dynamics of the ongoing neural activity. This default neural activity may be dynamically structured in time and space, showing regular, synchronized, bursting or chaotic activity patterns. We study the influence of non-synaptic plasticity on the default dynamical state of recurrent neural networks. The non-synaptic adaption considered acts on intrinsic neural parameters, such as the threshold and the gain, and is driven by the optimization of the information entropy. We observe, in the presence of the intrinsic adaptation processes, three distinct and globally attracting dynamical regimes, a regular synchronized, an overall chaotic and an intermittent bursting regime. The intermittent bursting regime is characterized by intervals of regular flows, which are quite insensitive to external stimuli, interseeded by chaotic bursts which respond sensitively to input signals. We discuss these finding in the context of self-organized information processing and critical brain dynamics.Comment: 24 pages, 8 figure

Ethyl 3-(6-phenyl-4λ4-1,2-dithiolo[1,5-b][1,2,4]dithia­zol-2-yl)propanoate

The title compound, C15H15NO2S3, exists in a bicyclic form, with resonance contributions from two monocyclic forms, each without a second S—S bond. The trithiapentalene heterocyclic ring system is planar, with a mean deviation of 0.014 (2) Å from the mean plane, and is inclined to the plane of the attached phenyl ring at an angle of 17.24 (7)°

Ispitivanje antioksidativnih mehanizama kempferola sa hidroksi radikalom i superoksid radikal anjonom

Kaempferol, one of the most bioactive plant flavonoids was theoretically (at M05-2X/6-311G(d,p) level of theory) investigated for its ability scavange potentially highly damaging hydroxyl and superoxide anion radicals. Theoretical calculations point to HAT and SPLET mechanisms as operative for kaempferol in all solvents under investigations.Teoretski (na M05-2X/6-311G(d,p) nivou teorije) je ispitivana sposobnost kempferola, važnog bioaktivnog biljnog jedinjenja flavonoida, da reaguje sa potencijalno veoma štetnim hidroksi radikalom i superoksid radikal anjonom. Proračuni su pokazali da su HAT i SPLET mogući mehanizmi u svim rastvaračima

Why should gender differences in hospitality really matter? A study of personnel’s service orientation and job satisfaction in hotels

In this article we examine the gender differences among hotel employees in service orientation and job satisfaction. To determine these differences, we used a service orientation scale (SOS), developed by Dienhart, Gregoire, Downey and Knight and a job satisfaction scale developed by Lytle. Our assumptions were that there would be significant gender differences in service orientation and job satisfaction. Our research proved factor structures of the two scales we used. Specifically, we showed gender differences in two of three factors, concerning service orientation (organisational support and customer focus), and no gender differences in job satisfaction. Our study revealed that organisational support is more important to men because they value more structured labour and service procedures than women (t = 2.21, df = 110, p = 0.03). In contrast, customer focus is more relevant to a women because it is more crucial to see satisfied guests, as well as having a good relationship with them (t = 2.07, df = 110, p = 0.04). It is of great importance for hotel management to have in mind that male and female employees respond and behave differently depending on the stimuli in the work environment and their satisfaction varies because of it

Sustainable Tourism as a Part of Comprehensive Environmental Monitoring. A Study of Serbia

The sustainable tourism comprises the freedom of tourist travelling, satisfying the economic, social and aesthetic needs, with the preservation of the characteristics of the natural and social environment and the cultural and historical heritage. It should optimize the usage of environmental resources that make the key element of tourism development, maintaining the essential ecologic processes and helping in heritage preservation, and providing the sustainable long-term business.As the consequences of the anthropogenic activities are obvious in the deterioration of the environment quality, the analysis of the status and influence on the environment and humans, as well as on the flora and fauna, must be under constant monitoring. The aim is to detect the corresponding influences and changes and to establish their cause. The paper approaches the structure, the processes and the application of the comprehensive monitoring of the environment with the aim of creating a database for the development of sustainable tourism in Serbia. The risk of the anthropogenic pollution of the environment, as a result of tourist activities, and monitoring of these activities in order to create a database for a planned and coordinated activity of tourism development will be considered in detail

Unstable compared to stable core exercises improve muscular endurance in preadolescents and adolescents: An eight-month randomized trial

Although previous studies have indicated the importance of a core strength and muscular endurance training in preadolescents and adolescents, there is a lack of evidence regarding effects of a long-term core training in unstable conditions. The purpose of this study was to compare the effects of core training in stable versus unstable body positions on core and upper body strength and muscular endurance in non-trained children aged 11-14 years. Participants were randomly assigned to either stable (SC, N=569) or unstable (UC, N=633) core-exercise group and assessed at baseline, after four, and eight months for sit-ups, dynamic trunk extension, static trunk extension, and push-ups. Repeated measures ANOVA, with time as a within factor, and exercise group, age, and gender as between factors, was employed for data analysis. Post-hoc comparisons showed greater absolute improvements after the eight-month training in UC compared to SC for all measures, age groups, and both genders (p≤.01), and greater relative improvements (differences in Cohen’s d between UC and SC ranged from 0.08 to 1.58), except for static trunk extension in 11- and 12-year-old participants. However, the differences between SC and UC in four-month effects were inconsistent. These results point out that core exercises in unstable compared to stable conditions have a greater capacity for long-term improvement of core and upper body strength and muscular endurance in non-trained preadolescents and adolescents

Bayesian sparsification for deep neural networks with Bayesian model reduction

Deep learning's immense capabilities are often constrained by the complexity of its models, leading to an increasing demand for effective sparsification techniques. Bayesian sparsification for deep learning emerges as a crucial approach, facilitating the design of models that are both computationally efficient and competitive in terms of performance across various deep learning applications. The state-of-the-art -- in Bayesian sparsification of deep neural networks -- combines structural shrinkage priors on model weights with an approximate inference scheme based on stochastic variational inference. However, model inversion of the full generative model is exceptionally computationally demanding, especially when compared to standard deep learning of point estimates. In this context, we advocate for the use of Bayesian model reduction (BMR) as a more efficient alternative for pruning of model weights. As a generalization of the Savage-Dickey ratio, BMR allows a post-hoc elimination of redundant model weights based on the posterior estimates under a straightforward (non-hierarchical) generative model. Our comparative study highlights the advantages of the BMR method relative to established approaches based on hierarchical horseshoe priors over model weights. We illustrate the potential of BMR across various deep learning architectures, from classical networks like LeNet to modern frameworks such as Vision Transformers and MLP-Mixers

Molecular design of nanoparticles and functional materials by sintering

Nanosized powders present an excellent starting point for the formation of nonporous materials during the sintering process. Narrow particle size distributions and sufficiently small sizes of the precursor powders typically present prerequisites for a successful sintering process. Different wet methods for the synthesis of nanoparticles with controlled physicochemical and morphological properties, alongside the multistep sintering approach at relatively low temperatures applied to convert the nanoparticles to materials with density close to theoretical, will present the focus of this presentation. Special attention will be paid to the design of multifunctional nanoparticles composed of various coexisting components, metallic, ceramic and polymer ones, and the properties resulting from the symmetry of their ordering. Obtainment of dense nanostructured materials from nanosized powders and the corresponding sintering mechanisms will be discussed in light of the general knowledge in this area. The process of densification during sintering of functionally gradient materials, including barium titanates and calcium phosphates, and a detailed correlation between the synthesis parameters, the material structure and characteristics will be elucidated in the course of the lecture

Synthesis and characterization of Cu-ZrB2 alloy produced by PM techniques

The copper alloy with 7vol.% ZrB2 examined in this study was consolidated via powder metallurgy processing (PM) by combining mechanical alloying and hot pressing process. Structural changes, morphological properties and elemental analysis of the hotpressed samples were studied as a function of milling time with the use of X-ray diffraction, scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometry (EDS). Also, mechanical properties of the Cu-7vol.%ZrB2 alloy was investigated. Distribution of ZrB2 particles and presence of agglomerates in the Cu matrix directly depend on the milling time and show strong influence on hardness, compressive and electrical properties of Cu-ZrB2 alloys. [Projekat Ministarstva nauke Republike Srbije, br. 172005