Rayleigh processes, real trees, and root growth with re-grafting

The real trees form a class of metric spaces that extends the class of trees with edge lengths by allowing behavior such as infinite total edge length and vertices with infinite branching degree. Aldous's Brownian continuum random tree, the random tree-like object naturally associated with a standard Brownian excursion, may be thought of as a random compact real tree. The continuum random tree is a scaling limit as N tends to infinity of both a critical Galton-Watson tree conditioned to have total population size N as well as a uniform random rooted combinatorial tree with N vertices. The Aldous--Broder algorithm is a Markov chain on the space of rooted combinatorial trees with N vertices that has the uniform tree as its stationary distribution. We construct and study a Markov process on the space of all rooted compact real trees that has the continuum random tree as its stationary distribution and arises as the scaling limit as N tends to infinity of the Aldous--Broder chain. A key technical ingredient in this work is the use of a pointed Gromov--Hausdorff distance to metrize the space of rooted compact real trees.Comment: 48 Pages. Minor revision of version of Feb 2004. To appear in Probability Theory and Related Field

Subtree prune and regraft: a reversible real tree-valued Markov process

We use Dirichlet form methods to construct and analyze a reversible Markov process, the stationary distribution of which is the Brownian continuum random tree. This process is inspired by the subtree prune and regraft (SPR) Markov chains that appear in phylogenetic analysis. A key technical ingredient in this work is the use of a novel Gromov--Hausdorff type distance to metrize the space whose elements are compact real trees equipped with a probability measure. Also, the investigation of the Dirichlet form hinges on a new path decomposition of the Brownian excursion.Comment: Published at http://dx.doi.org/10.1214/009117906000000034 in the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

Scope of ornamental fisheries in snow fed rivers of Uttarakhand - Overview

Upland rivers of hills of Uttarakhand are unique in its ecosystem and biodiversity. These waters possess various varieties of ornamental fishes. The present study focuses on Scope of ornamental fisheries in snow fed rivers of Uttarakhand, along with challenges and opportunities. Besides the availability of resources peoples are not that much aware of ornamental fisheries of this region and these resources are yet not developed. The use of destructive fishing methods, habitat destruction leads to diversity destruction of hills stream fishes. As theseresources does not comprise fisheries of commercial importance due to sparse biota and low thermal scale, slow growth and very low natural food availability So, Directorate of Cold Water Fisheries is actively working in the field of survey and brood stock management of ornamental fish resources of cold water. Four hundred live cold water fishes including exotic gold and koi carp are being maintained at DCFR main complex for study and breeding trials. The recreational activities by fisheries department like ranching, sport fisheries development and development of ornamental fisheries of this region can lead to socioeconomic upliftment of hilly people and development of cold water ornamental fisheries in the state

Using Feedback In Teaching Writing Descriptive Text

This study is to see the improvement of student's writing skill on descriptive text for seventh grade students of SMP 14 Kota Serang by using peer feedback technique. The subject of this research is the students of seventh grade of SMP 14 Kota Serang which consist of 30 students. This research is applied by a quasi-experimental design and quantitative research method. The instrument used in this research was tests (pre-test and post-test) which is conducted based on the main problems: 1) How is the students writing ability on descriptive text at the seventh grade of SMP 14 Kota serang? 2) How is the effectiveness of peer feedback in teaching writing descriptive text at the seventh grade of SMP 14 Kota serang?. The research finding of the last result showed that “to” from the calculation is higher than t table both at significance level 5% and 1%. Significance 5% t observation= 7.14 and t table= 1.67 or 7.14 >1.67 which its significance 1% t observation=7.14 and t table= 2.39 or 7.14 >2.39. In addition, the result of observations showed that the students more motivated in learning English, especially for writing subject. Based on the result above, it can be concluded that peer feedback can be used in teaching writing descriptive text. The result of this research shows that the students' writing on descriptive text who use peer feedback achieve better performance than those who do not use it. &nbsp

Upaya Meningkatkan Hasil Belajar Fisika Melalui Metode Cooperative Script Pada Siswa Kelas VIII SMP Darul Hikmah Makassar

Penelitian ini adalah penelitian tindakan kelas (classroom action research) yang bertujuan untuk mengetahui apakah metode pembelajaran Cooperative Script dapat meningkatkan hasil belajar fisika siswa kelas VIII SMP Darul Hikmah Makassar. Subjek penelitian ini adalah siswa kelas VIII SMP Darul Hikmah Makassar pada semester genap tahun pelajaran 2013/2014 dengan jumlah siswa 46 orang. Penelitian ini dilaksanakan sebanyak dua siklus, pengambilan data dilakukan dengan menggunakan tes hasil belajar dan observasi. Data hasil belajar dianalisis dengan menggunakan analisis kuantitatif dan data hasil observasi dianalisis dengan analisis kualitatif. Hasil penelitian menunjukkan bahwa nilai rata-rata siswa pada siklus I sebesar 68,48. Sedang pada siklus II diperoleh nilai rata-rata siswa sebesar 73,55. Hal ini memperlihatkan adanya peningkatan hasil belajar fisika. Dari hasil penelitian ini dapat disimpulkan bahwa dengan diterapkan metode pembelajaran Cooperative Script pada siswa kelas VIII SMP Darul Hikmah Makassar dalam proses pembelajaran, maka hasil belajar fisika, dan keaktifan siswa dapat meningkat.Kata kunci: Hasil Belajar, Cooperative Script.This research is a class action (classroom action research), which aims to determine whether the Script Cooperative learning methods to improve learning outcomes physics class VIII SMP Darul Hikmah Makassar. The subjects were students of class VIII SMP Darul Hikmah Makassar in the second semester of the school year 2013/2014 the number of students 46 people. This research was conducted as many as two cycles, data collection is done by using test results of study and observation. Learning outcomes data were analyzed using quantitative analysis and data analyzed by the observation of qualitative analysis. The results showed that the average value of students in the first cycle of 68.48. Meanwhile in the second cycle obtained by the average value of 73.55 students. This represents an increase learning outcomes physics. From these results it can be concluded that the applied learning methods Cooperative Script in class VIII SMP Darul Hikmah Makassar in the learning process, then the results of studying physics, and student activity can be increased

Functional characterization of a glutamate/aspartate transporter from the mosquito Aedes aegypti

Glutamate elicits a variety of effects in insects, including inhibitory and excitatory signals at both neuromuscular junctions and brain. Insect glutamatergic neurotransmission has been studied in great depth especially from the standpoint of the receptor-mediated effects, but the molecular mechanisms involved in the termination of the numerous glutamatergic signals have only recently begun to receive attention. In vertebrates, glutamatergic signals are terminated by Na^+/K^+-dependent high-affinity excitatory amino acid transporters (EAAT), which have been cloned and characterized extensively. Cloning and characterization of a few insect homologues have followed, but functional information for these homologues is still limited. Here we report a study conducted on a cloned mosquito EAAT homologue isolated from the vector of the dengue virus, Aedes aegypti. The deduced amino acid sequence of the protein, AeaEAAT, exhibits 40–50% identity with mammalian EAATs, and 45–50% identity to other insect EAATs characterized thus far. It transports l-glutamate as well as l- and d-aspartate with high affinity in the micromolar range, and demonstrates a substrate-elicited anion conductance when heterologously expressed in Xenopus laevis oocytes, as found with mammalian homologues. Analysis of the spatial distribution of the protein demonstrates high expression levels in the adult thorax, which is mostly observed in the thoracic ganglia. Together, the work presented here provides a thorough examination of the role played by glutamate transport in Ae. aegypti

Silver-Polymer Nanocomposites

The objective of this research was the development of an efficient method for the preparation of silver-polymer nanocomposites containing finely dispersed silver nanoparticles. The surface of nanosilver was functionalized by thiolation with 2-aminoethanethiol. Amino-modified nanosilver was covalently bonded to polyacrylic acid, biodegradable polymers like acid terminated polylactic acid, ester terminated poly(DL-lactide-co-glycolide) and acid terminated poly(DL lactide-co-glycolide) in the presence of diisopropylcarbodiimide by carbodiimide method. Esterification of the carboxyl groups of Ag-polyacrylic acid by hydrochloric acid in methanol resulted in the formation of a stable colloidal dispersion of Ag nanoparticles in the polymer matrix. It was observed that not just acid terminated polymers but also ester terminated polymers could react with functionalized nanosilver. This unusual reaction was due to the aminolysis of the ester bond in the polymer chain by the surface amino groups. Silver-polymer nanocomposites obtained with acid terminated polylactic acid and poly(DL-lactide-co-glycolide) contained highly dispersed nanosilver in the polymer matrix in comparison with the ester terminated poly(DL-lactide-co-glycolide). Chemical and structural characteristics of the obtained materials were studied by instrumental methods. Attained biodegradable materials confirmed X-ray contrast and bactericidal properties, which could be eventually used for biomedical applications

Using an Astrophysical Model to Characterize Nuclear Dust

Dust clouds resulting from nuclear explosions are complex phenomena, and knowledge on how they form is lacking. Noting the similarities between supernovae and nuclear explosions led to the concept of modeling a nuclear dust cloud using a supernova simulation. MOCASSIN uses a Monte Carlo approach to model photons traveling through a dust cloud, allowing the cloud\u27s characteristics to be discovered by comparing an observed spectrum to a calculated one and then changing input values to make the spectra match. Data files describing two nuclear fireballs of varying yields were created and analyzed using MOCASSIN, but yielded zero energy spectra. After varying the parameters of the tests, analyzing the resulting spectra, and comparing them to data, it was found that the differences between the nuclear explosion and supernova were too significant for MOCASSIN to accurately model both. Insufficient input data for nuclear materials, and low ionization levels and high densities in the fireball were insurmountable issues. Ultimately, it was concluded that MOCASSIN is not a viable method for analyzing nuclear explosions