Maximum a posteriori estimation through simulated annealing for binary asteroid orbit determination

This paper considers a new method for the binary asteroid orbit determination problem. The method is based on the Bayesian approach with a global optimisation algorithm. The orbital parameters to be determined are modelled through an a posteriori distribution made of a priori and likelihood terms. The first term constrains the parameters space and it allows the introduction of available knowledge about the orbit. The second term is based on given observations and it allows us to use and compare different observational error models. Once the a posteriori model is built, the estimator of the orbital parameters is computed using a global optimisation procedure: the simulated annealing algorithm. The maximum a posteriori (MAP) techniques are verified using simulated and real data. The obtained results validate the proposed method. The new approach guarantees independence of the initial parameters estimation and theoretical convergence towards the global optimisation solution. It is particularly useful in these situations, whenever a good initial orbit estimation is difficult to get, whenever observations are not well-sampled, and whenever the statistical behaviour of the observational errors cannot be stated Gaussian like.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Decrease of vanillin sucrose intake by victorious and defeated mice: development of anhedonia?

Hedonic reactions to various rewards play a key role in various forms of motivated behavior. The influence of repeated experience of social victories or defeats in daily agonistic interactions between male mice on voluntary consumption of vanillin sucrose solution used as hedonic reinforcer was studied. Intake of vanillin sucrose solution was shown to decrease in the winners and losers exposed to social confrontations as compared with the controls. Three days of deprivation failed to restore the intake of vanillin sucrose solution to the control level in the losers and did so in the winners. The results obtained imply that similar reaction of animals to a hedonic non-drug reinforcer may have different motivational origin depending on positive or negative social experience

Experience of Social Interaction of a Future Specialist as a Unified Basis for Continuous Education

The implementation of the competency-based approach in a multi-level education system has posed the problem of continuity of its levels. The search for common grounds in choosing the content and results of education has intensified. The scientific interest in the student’s experience has grown, as the basic basis for the formation of competencies. Experience is an extremely general category in the scientific apparatus of many sciences, such as philosophy, sociology, psychology, pedagogy, and understanding of its essential properties determines the choice of the content of education. Increasingly, the experience of human behavior in a changing society is becoming the subject of research by educators. Educational standards for training specialists in the sociogenic sphere contain a capacious block of social competencies formed in the educational process at the meta-subject and subject levels. The difficulty of ensuring the systemic integrity of the content of education, which includes individual, disparate elements of activity reflected in the social competencies of a future specialist, determines the theoretical and experimental search for an effective educational construct that maximally covers the content of these competencies and the ways of its formation. The genesis of the concept of social interaction indicates the progressive movement of scientific ideas from a socially insignificant and little studied phenomenon to its dominant role in the formation and development of social reality. In most psychological and pedagogical concepts, experience is considered as a passive result of activity, which determines its static structure. The dynamic structure of the experience of social interaction is formed by the value-semantic, thought-activity and expressive-activity components. Subjectivity, co-existence, and reflexivity are proposed as the through lines of its enrichment for all levels of education. The results of the study can serve as a theoretical basis for designing the enrichment of the experience of social interaction of students at different levels of education

Molecular implications of prolonged aggression experience: Th, Dat1, Snca and Bdnf gene expression in the ventral tegmental area of the victorious male mice

Th, Dat1, Snca and Bdnf were the genes whose mRNA levels in the ventral tegmental area of the midbrain were measured in male mice that were victorious in 20 daily agonistic interactions and in a group of such victorious mice that had later not been allowed to fight for 14 days. This experiment demonstrated increased Th, Dat1 and Snca but not Bdnf mRNA levels in the former group as compared to the controls. In the latter group, the expression of the Th and Dat1 genes was still enhanced, while the level of Snca mRNA did not differ from that in the controls. These findings suggest that positive fighting experience enhances the expression of the genes concerned with dopaminergic systems and this enhanced expression is preserved for a long time afterwards. Significant positive correlations were found between the level of aggression and Th and Snca mRNA levels in the winners

Anhedonia in the shadow of chronic social defeat stress, or When the experimental context matters

One of the core symptoms of major depression in human is anhedonia. For that reason, one of the main requirements towards experimental depression models is that they be able to demonstrate anhedonia in animals, that have been exposed to stressful events, and other behavioral changes attributable to a depression-like state. However, the results presented in the literature are contradictory: sweet solution intake, which is considered as a parameter of hedonic/anhedonic behavior in animals, responds quite differently to stressful situations in that it is either unaffected or increased or decreased. Different experimental designs used for the study of anhedonia in male mice exposed to chronic social defeat stress were tried to understand the reasons for so contradictory responses. Anhedonia appears as an abrupt reduction in sweet solution consumption in stressed animals and by failure to attain recovery after deprivation. However, it was also demonstrated that sucrose solution intake and preference strongly depend on the experimental context; that the possible critical factor may be prior acquaintance with the hedonic stimulus – or the lack whereof. Analysis of literature data and ours allowed us to conclude that the lack of a significant decrease in sweet solution intake in stressed animals is no evidence of lack of depression. This decrease is evidence of anhedonia only provided other symptoms of depression are present. Hedonic consumable intake can be decreased over various motivations, conditions or diseases, in particular, a high level of anxiety or pathological aggression

Application of the Sensory Contact Model for Pharmacological Studies under Simulated Clinical Conditions

The sensory contact model allows forming different psycho-pathological states (anxious depression, catalepsy, social withdrawal, pathological aggression, cognition disturbances, anhedonia, addictive states etc.) produced by repeated agonistic interactions in male mice and investigating the therapeutic and preventive properties of any drug as well as its efficiency under simulated clinical conditions. This approach can be useful for a better understanding of the drugs’ action in different stages of disease development in individuals. It is suggested that this behavioral approach and pharmacological designs may be applied for the screening of novel psychotropic drugs. 
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Methods of Social Interaction Learning for Students of Non-Profit Organizations

Search and substantiation of new form productivity for student non-formal education, which make it possible to compensate for the deficit of purposeful preparation for social interaction in the traditional (formal) system of higher education. Methodology: system-dialectical approach, which allows to overcome the existing fragmentation and the fragmentation of research results concerning the experience of student social interaction; the methods of scientific analysis of sources; pedagogical experience study; comparative analysis; classification; content analysis; mathematical processing of statistical data. Results: they substantiate the relevance of addressing social education of students in youth non-profit organizations, as one of the forms of non-formal education. The individual and group experience of social interaction and its promising lines of enrichment (subjectivity, reflexivity, co-existence) are proposed as a system-organized educational result. The content of education is determined based on the characteristics of social practices implemented in non-profit organizations. The results of the comparative study of the applied forms and methods of youth training in existing youth non-profit organizations in Russia and abroad (the Association of Trainers of the Russian Union of Youth, the All-Russian School of Personal Growth and Development of Student Self-Government "Progress", "The College of Trainers by T. Hoist" (Germany), "Freechild Institute" (USA). The methods of social training of their participants most widespread in non-profit organizations, the features and results of their application are determined. The conclusions are made about the relevance and prospects of student youth preparation optimization for active social interaction in non-formal education within the context of non-profit organizations based on the methodology of the system-dialectical approach to the enrichment of individual and group experience of social interaction

Statistical inversion method for binary asteroids orbit determination

International audienceWe focus on the study of binary asteroids, which are common in the Solar system from its inner to its outer regions . These objects provide fundamental physical parameters such as mass and density, andhence clues on the early solar sytem, or ooher processes that are affecting asteroid over time. The present method of orbit computation for resolved binaries is based on Markov Chain Monte-Carlo statistical inversion technique. Particularly we use the metropolis-hasting algorithm with Thiele - Innes equation for sampling the orbital elements and system mass through the sampling observations. The method requires a minimum of four observations, made at the same tangent plane; it is of particular interest for orbit determination over short ars or with sparse data. The observations are sampled within their observationale errors with an assumed distribution. The sampling yields the whole region of possible orbits including the one that is most probable.

Asteroid selection database for space mining mission analysis

The near-Earth asteroids (NEAs) may be the most accessible as resources in space to be used for propellant, space manufacturing, and life support. Within this context the multidisciplinary project Ecocel (stands for “Exploitation des Ressources des Corps Célestes”) conducts study on exploration and commercial exploitation of celestial bodies in order to provide recommendations for the French Government. A selection of accessible ressources is an important part of space mining consideration. For this purpose, a database and astrodynamics tools were developed to enable a selection making of asteroids-candidates and a trajectory analysis to compare different mission scenarios. The database contains 326 NEAs, and includes information about basic physical and orbital parameters, collected from JPL Small-Body Database. In addition, the database has been completed by composition data, inferred from spectral classification of NEAs and linked meteorites data. The astrodynamics tools enable to compute one-way and round-trip missions opportunities, using patched two-body approximation, with Lambert solver and ephemerides from the JPL HORIZONS system. The missions characteristics, such as delta-v budget and time of flight, are summarised in the database for each object, and incorporate 20 precomputed solutions optimised by delta-v cost over 2025-2050 launch period. Compared to existing databases, the new database and tools are enable to select potential mission target asteroids by both criteria – composition and accessibility. The data analysis results, the used methods and demonstration on study cases will be presented