Limit theory for planar Gilbert tessellations

A Gilbert tessellation arises by letting linear segments (cracks) in the plane unfold in time with constant speed, starting from a homogeneous Poisson point process of germs in randomly chosen directions. Whenever a growing edge hits an already existing one, it stops growing in this direction. The resulting process tessellates the plane. The purpose of the present paper is to establish law of large numbers, variance asymptotics and a central limit theorem for geometric functionals of such tessellations. The main tool applied is the stabilization theory for geometric functionals.Comment: 12 page

Debating whether Dinosaurs Should be "Cloned" from Ancient DNA to Promote Cooperative Learning in an Introductory Evolution Course

This interactive internet exercise engages students in cooperative library and web research on a controversial topic in science (and ethics), specifically the cloning of extinct forms of life. To debate the many complex issues embedded in this topic, students have to apply knowledge acquired from a variety of sources about dinosaurs, their evolutionary history, diversity, distribution, physiology, behavior, environmental requirements, and extinction. They must achieve a general understanding of the techniques used to discover and retrieve ancient DNA and to produce a clone from a living adult animal. During an in-class "trial," two teams of students representing six types of specialists argue cases for and against dinosaur cloning. Student "judges" hear testimony, pose questions to the specialists, and render their verdict about whether dinosaur cloning should be allowed. Working cooperatively in small groups and arguing a position in an authoritative fashion requires students to exercise their communication (written and oral), collaborative, and critical thinking skills. This exercise creates a dynamic learning environment in a moderately large introductory geology course and demonstrates the importance of scientific literacy in the contemporary experience. Educational levels: Graduate or professional

Demographic development and changes of land-use in the Beskid Niski Mountains, Poland, between 1869 and 2009

Two different stages of demographic development with successive changes in land- use patterns and directions can be distinguished in the Beskid Niski in Poland during the past 140 years. These stages are separated by tragic events this region experienced in the 1940s (forced population resettlement). The first stage of demographic development is characterised by natural, consecutive changes comparable to other areas in the whole Carpathians. The second stage stretches from the end of World War II until the present day. The "revolutionary" character and changes initiated by this stage are nothing like these observed in other regions of the Polish Carpathians back then as well as presently (except for Bieszczady Mountains). Stemming from rapid demographic processes most changes are observed in land-use and natural environment (unexpectedly halted anthropopression), although they also affect social structures and economic processes specific for mountainous areas

Konsep Diri pada Penyandang Cacat Fisik Pasca Amputasi di BBRSBD Prof. DR. Soeharso Surakarta

Konsep diri mempunyai peran penting dalam menentukan perilaku individu. Individu yang mengalami cacat secara fisik mengalami perasaan takut gagal, tidak percaya diri, merasa tidak berguna sehingga kurang berhasil dalam kehidupan sehari-hari. Penelitian ini bertujuan untuk mengetahui bagaimana konsep diri pada penyandang cacat pasca amputasi serta dinamika psikologis yang dialami penyandang cacat fisik pasca amputasi. Subjek dalam penelitian ini adalah siswa dari BBRSBD Prof. Dr. Soeharso Surakarta dengan rentang usia 17-25 tahun. Metode pengambilan data yang digunakan dalam penelitian ini adalah menggunakan wawancara, observasi umum, dan observasi diri (behavioral checklist) yaitu subjek mengisi dan memberikan checklist pada pertanyaan yang sudah tersedia sesuai dengan kondisi yang dialami subjek. Dalam penelitian ini data yang diperoleh merupakan data kualitatif yaitu data yang bersifat narasi deskripsi. Hasil penelitian menunjukkan bahwa penyandang cacat fisik pasca amputasi di BBRSBD Prof. Dr. Soeharso Surakarta memiliki konsep diri yang pada awalnya merasa kekurangan secara fisik yang menimbulkan rasa kurang/tidak percaya diri, malu, minder serta cenderung menghindar. Hal ini terjadi karena penyandang cacat fisik merasa tidak nyaman dengan penolakan dari lingkungan. Meskipun demikian pada akhirnya, penyandang cacat fisik dapat menerima kondisi fisik mereka karena mereka ingin hidup mandiri serta sukses meskipun keadaan fisik telah cacat. Selain itu penyandang cacat fisik mendapat dukungan serta motivasi dari keluarga, teman-teman dan pembina asrama BBRSBD Prof Dr. Soeharso Surakarta dan dengan kondisi tersebut mereka dapat tetap membantu dan menolong orang lain yang membutuhkannya

Heliospheric modulation of the interstellar dust flow on to Earth

Aims. Based on measurements by the Ulysses spacecraft and high-resolution modelling of the motion of interstellar dust (ISD) through the heliosphere we predict the ISD flow in the inner planetary system and on to the Earth. This is the third paper in a series of three about the flow and filtering of the ISD. Methods. Micrometer- and sub-micrometer-sized dust particles are subject to solar gravity and radiation pressure as well as to interactions with the interplanetary magnetic field that result in a complex size-dependent flow pattern of ISD in the planetary system. With high-resolution dynamical modelling we study the time-resolved flux and mass distribution of ISD and the requirements for detection of ISD near the Earth. Results. Along the Earth orbit the density, speed, and flow direction of ISD depend strongly on the Earth's position and the size of the interstellar grains. A broad maximum of the ISD flux (2x10^{-4}/m^2/s of particles with radii >~0.3\mu m) occurs in March when the Earth moves against the ISD flow. During this time period the relative speed with respect to the Earth is highest (~60 km/s), whereas in September when the Earth moves with the ISD flow, both the flux and the speed are lowest (<~10 km/s). The mean ISD mass flow on to the Earth is ~100 kg/year with the highest flux of ~3.5kg/day occurring for about 2 weeks close to the end of the year when the Earth passes near the narrow gravitational focus region downstream from the Sun. The phase of the 22-year solar wind cycle has a strong effect on the number density and flow of sub-micrometer-sized ISD particles. During the years of maximum electromagnetic focussing (year 2031 +/- 3) there is a chance that ISD particles with sizes even below 0.1\mu m can reach the Earth. Conclusions. We demonstrate that ISD can be effectively detected, analysed, and collected by space probes at 1 AU distance from the Sun.Comment: 17 pages, 17 figure

Tension points in real social science: A response

Social science today often contents itself with trying to explain particular events in terms of general models without understanding those events as experienced by the people being studied and without providing ?ndings that might help people address the problems they are experiencing. It can be argued that the recent development of social science has focused too much on its own ?evidence-inference methodological core? and has lost sight of what is being studied, who is being studied, and how the results of research can challenge popular understanding, misconceptions, and power relations. At the most basic level, our edited volume Real Social Science: Applied Phronesis (Flyvbjerg, Landman and Schram 2012) is designed to provide examples of research that is situated in real communities, grows out of the concerns of people in those communities and is conducted in ways that can help those people address those concerns. These examples demonstrate that what we are calling ?phronetic social science? (as originally coined by Bent Flyvbjerg) offers a meaningful approach for making social science useful and relevant to real people experiencing real problems. Phronetic social science calls for social scientists foregoing the attempt to build generic models of social behaviour and instead situate their work in ongoing political struggles as they occur in speci?c contexts

Social exclusion and transportation in Peachtree City, Georgia

This paper will discuss how, in a small American city, Peachtree City (43km south of Atlanta), the flexibility and relative affordability of electric golf carts, as a viablealternative to the automobile, means that the level at which families and individuals are disadvantaged through their lack of access to public/private transport is effectively lowered. Economic access to golf carts, in of itself, would not be sufficient if it were not for the extensive, highly penetrative and 'ringy' spatial structure of the cart path system, a mostly-segregated, 150 kilometre network. A spatial analysis of this dual transportation system is presented and its implications discussed. The conclusion of this paper is that the duality of the effective spatial structure of the cart path networkand the relative low cost and inherent flexibility of the golf carts combine to reduce transportation-linked social exclusion in Peachtree City. This argument is substantiated, in the final section of the paper, through the evidence of a questionnairedistributed to a random sampling of 1,038 property owners and renters in the city