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

Aerodynamic Benefits of Near-Surface-Actuated Circulation Control Blowing Slots for Rotorcraft Use

One of the most maintenance intensive components of all present-day helicopters is the swash-plate, and its associated control linkages. This mechanism is also the major contributing factor to fatal accidents associated with helicopter flight. However, the swash-plate is an essential component in providing controlled flight, by transmitting the pilot\u27s control-inputs to the main rotor. Another side-effect of using the swash-plate is that it increases the diameter of the main rotor shaft assembly, slightly increasing the total drag of the aircraft. Thus, there are several benefits that could be achieved by removing the swash-plate of the helicopter.;To enable the removal of the swash-plate from a rotorcraft, a method is needed to augment the aerodynamic performance of the main rotor blades as a function of azimuth angle, while maintaining the traditional cyclic and collective pilot controls. Circulation control can provide a means of changing the aerodynamic performance without physically changing the angle of attack of the blade, as is currently done by the swash-plate. Thus, the current project was conceived to investigate the use of surface-mounted valves to control leading and trailing edge circulation control blowing as a means of decreasing the flow establishment time for circulation control wing lift augmentation.;Both experimental and computational methods were implemented in this study. From the experimental results, a lift augmentation ratio (C 1/Cmu) of 47 could be achieved in 56 msec, with the model at an angle of attack of 0.68 degrees. The computational study yielded a force establishment time of 55 to 60 msec to achieve a lift coefficient greater than 5 at 0 degree angle of attack. From this data it is concluded that the use of a circulation control airfoil, with blowing jet controlled at or near the airfoil surface, can effectively be used on a helicopter main rotor if the rotor speed is less than 275 rpm with four defined force control points per revolution. The rotational speed is within the operational range of current technology rotor speeds

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

META ANALISIS PENDEKATAN BERDIFERENSIASI PADA PEMBELAJARAN FISIKA

Salah satu cara yang dapat diambil oleh guru untuk meningkatkan prestasi belajar dan keterampilan proses sains siswa dalam pembelajaran fisika di SMA adalah melalui penggunaan pendekatan berdiferensiasi. Pendekatan ini dikenal sebagai strategi instruksional yang membantu guru dalam manajemen kelas, mengarahkan pembelajaran, serta mendorong dan memantau perkembangan siswa sehingga setiap siswa dapat mencapai hasil belajar yang optimal. Penelitian ini bertujuan untuk mengevaluasi efektivitas pendekatan berdiferensiasi dalam pembelajaran fisika di SMA, menggunakan metode Meta Analisis dengan teknik perhitungan effect size. Sampel penelitian terdiri dari 20 artikel ber- ISSN. Hasil penelitian menunjukkan beberapa temuan penting: 1) Rata-rata effect size dari penerapan pendekatan berdiferensiasi dalam pembelajaran fisika di SMA adalah sebesar 1,95 dengan kategori tinggi. Hal ini menunjukkan bahwa pendekatan berdiferensiasi efektif dalam meningkatkan hasil belajar dan keterampilan proses sains siswa dalam pembelajaran fisika di SMA; 2) Pada tingkat pendidikan SMA, pendekatan berdiferensiasi yang terbimbing memberikan pengaruh yang lebih besar dibandingkan dengan jenis pendekatan lainnya terhadap pembelajaran fisika. Dengan demikian, dapat disimpulkan bahwa penerapan pendekatan berdiferensiasi dalam pembelajaran fisika di SMA membawa dampak positif yang signifikan, terutama ketika pendekatan tersebut diarahkan dan dibimbing secara efektif.Kata kunci: Pendekatan Berdiferensiasi, Pembelajaran Fisika

Switched Reluctance Motor Drives for Hybrid Electric Vehicles

Because of the ever‐increasing concerns on the energy utilization and environmental protection, the development of hybrid electric vehicles (HEVs) has become a hot research topic. As the major part of HEV technologies, the electric motor drives have to offer high efficiency, high power density, high controllability, wide‐speed operating range, and maintenance‐free operation. In particular, the switched reluctance (SR) motor drive can achieve most of these goals; therefore, this motor type has drawn much attention in the past. This chapter aims to serve as an overview of the latest developments of the SR motor drive, purposely for HEV applications. To be specific, the discussions on motor structures for torque density enhancement and torque ripple minimization are covered

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

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

The Kuznets Curve and the Inequality Process

Four economists, Mauro Gallegati, Steven Keen, Thomas Lux, and Paul Ormerod, published a paper after the 2005 Econophysics Colloquium criticizing conservative particle systems as models of income and wealth distribution. Their critique made science news: coverage in a feature article in Nature. A particle system model of income distribution is a hypothesized universal statistical law of income distribution. Gallegati et al. (2006) claim that the Kuznets Curve shows that a universal statistical law of income distribution is unlikely and that a conservative particle system is inadequate to account for income distribution dynamics. The Kuznets Curve is the graph of income inequality (ordinate variable) against the movement of workers from rural subsistence agriculture into more modern sectors of the economy (abscissa). The Gini concentration ratio is the preferred measure of income inequality in economics. The Kuznets Curve has an initial uptick from the Gini concentration ratio of the earned income of a poorly educated agrarian labor force. Then the curve falls in near linear fashion toward the Gini concentration ratio of the earned incomes of a modern, educated labor force as the modern labor force grows. The Kuznets Curve is concave down and skewed to the right. This paper shows that the iconic Kuznets Curve can be derived from the Inequality Process (IP), a conservative particle system, presenting a counter-example to Gallegati et al.’s claim. The IP reproduces the Kuznets Curve as the Gini ratio of a mixture of two IP stationary distributions, one characteristic of the wage income distribution of poorly educated workers in rural areas, the other of workers with an education adequate for industrial work, as the mixing weight of the latter increases and that of the former decreases. The greater purchasing power of money in rural areas is taken into account