Gamma-distribution and wealth inequality

We discuss the equivalence between kinetic wealth-exchange models, in which agents exchange wealth during trades, and mechanical models of particles, exchanging energy during collisions. The universality of the underlying dynamics is shown both through a variational approach based on the minimization of the Boltzmann entropy and a complementary microscopic analysis of the collision dynamics of molecules in a gas. In various relevant cases the equilibrium distribution is the same for all these models, namely a gamma-distribution with suitably defined temperature and number of dimensions. This in turn allows one to quantify the inequalities observed in the wealth distributions and suggests that their origin should be traced back to very general underlying mechanisms: for instance, it follows that the smaller the fraction of the relevant quantity (e.g. wealth or energy) that agents can exchange during an interaction, the closer the corresponding equilibrium distribution is to a fair distribution.Comment: Presented to the International Workshop and Conference on: Statistical Physics Approaches to Multi-disciplinary Problems, January 07-13, 2008, IIT Guwahati, Indi

Relaxation in statistical many-agent economy models

We review some statistical many-agent models of economic and social systems inspired by microscopic molecular models and discuss their stochastic interpretation. We apply these models to wealth exchange in economics and study how the relaxation process depends on the parameters of the system, in particular on the saving propensities that define and diversify the agent profiles.Comment: Revised final version. 6 pages, 5 figure

Gator: a low-background counting facility at the Gran Sasso Underground Laboratory

A low-background germanium spectrometer has been installed and is being operated in an ultra-low background shield (the Gator facility) at the Gran Sasso underground laboratory in Italy (LNGS). With an integrated rate of ~0.16 events/min in the energy range between 100-2700 keV, the background is comparable to those of the world's most sensitive germanium detectors. After a detailed description of the facility, its background sources as well as the calibration and efficiency measurements are introduced. Two independent analysis methods are described and compared using examples from selected sample measurements. The Gator facility is used to screen materials for XENON, GERDA, and in the context of next-generation astroparticle physics facilities such as DARWIN.Comment: 14 pages, 6 figures, published versio

Peran Sarana Pelayanan Kesehatan Terhadap Kejadian Malaria Di Kecamatan Silian Raya Kabupaten Minahasa Tenggara

: The problem of public health, especially in developing coutries such as Indonesia, is based on the physical aspects such as health facilities, the treatment of disease, and non physical aspects related to the health problem. Malaria is still a public health problem because it often creates exrtraordinary events, which has great impact on quality on life and economy, and may result death. The main keys of reducing the incidence of malaria especially in high endemic areas are prevention and treatment. This study aimed to determine the role of health care facilities on the incidence of malaria in Silian Raya sub-district of Southheast Minahasa district. This was a descriptive survey study. The population was the community in Silian Raya sub-district of Southeast Minahasa district with total samples 194 respondents. The results showed that the counseling done by health workers was at the most 2 times (39.2%). Spraying insecticide by health workers was 1 time (41.8%). People that used the available health care facilities in Silian Raya sub-district, the health center, were 51.0%

Hubungan Kadar Tumor Necrosis Factor – Α Dengan Densitas Plasmodium Pada Penderita Malaria

: Malaria is a parasitic infection that attacks the erythrocytes. This disease remains a global health problem, especially in developing countries in the tropics and subtropics. Symptomatic malaria infection include fever, chills, anemia and splenomegaly. Malaria infection can progress without any complications but can also develop systemic complications known as severe malaria. The cause of malaria is plasmodium infection, Plasmodium in humans infected erythrocytes (red blood cells) and asexual breeding experience in liver tissue and erythrocytes. In this research, the microscopic examination of blood samples for counting malaria parasites in the blood and then measured the levels of TNF-α by ELISA. This analytical study using 40 samples taken by simple random sampling. The results showed that there is a significant relationship between the amount of TNF-α levels plasmodium with. Conclusions: There were significant correlation between the levels of TNF-α with a density of plasmodium malaria in blood samples

Peranan Lingkungan Terhadap Kejadian Malaria Di Kecamatan Silian Raya Kabupaten Minahasa Tenggara

: Malaria, an infectious disease, is still an issue for public health world-wide, including in Indonesia. Malaria is caused by Plasmodium Sp. which is transmitted by the Anopheles mosquito. Southeast Minahasa Regency has high malaria rate. This study aimed to know the role of the environment on the incidence of malaria in Silian Raya subdistrict, Southeast Minahasa regency. This was a descriptive survey. The population was the community in Silian Raya subdistrict, Southeast Minahasa regency with 194 respondents. The results showed that people in Silian Raya subdistrict mostly live around swamps, rice paddies, and rivers. This study also showed that only a few people of Silian Raya subdistrict who had pets, and fish ponds around their houses

Entropy and equilibrium state of free market models

Many recent models of trade dynamics use the simple idea of wealth exchanges among economic agents in order to obtain a stable or equilibrium distribution of wealth among the agents. In particular, a plain analogy compares the wealth in a society with the energy in a physical system, and the trade between agents to the energy exchange between molecules during collisions. In physical systems, the energy exchange among molecules leads to a state of equipartition of the energy and to an equilibrium situation where the entropy is a maximum. On the other hand, in the majority of exchange models, the system converges to a very unequal condensed state, where one or a few agents concentrate all the wealth of the society while the wide majority of agents shares zero or almost zero fraction of the wealth. So, in those economic systems a minimum entropy state is attained. We propose here an analytical model where we investigate the effects of a particular class of economic exchanges that minimize the entropy. By solving the model we discuss the conditions that can drive the system to a state of minimum entropy, as well as the mechanisms to recover a kind of equipartition of wealth

Critical slowing down in polynomial time algorithms

Combinatorial optimization algorithms which compute exact ground state configurations in disordered magnets are seen to exhibit critical slowing down at zero temperature phase transitions. Using arguments based on the physical picture of the model, including vanishing stiffness on scales beyond the correlation length and the ground state degeneracy, the number of operations carried out by one such algorithm, the push-relabel algorithm for the random field Ising model, can be estimated. Some scaling can also be predicted for the 2D spin glass.Comment: 4 pp., 3 fig