1,184 research outputs found

    Aussterberisiko kleiner Populationen

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    Dynamics of Competitive Evolution on a Smooth Landscape

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    We study competitive DNA sequence evolution directed by {\it in vitro} protein binding. The steady-state dynamics of this process is well described by a shape-preserving pulse which decelerates and eventually reaches equilibrium. We explain this dynamical behavior within a continuum mean-field framework. Analytical results obtained on the motion of the pulse agree with simulations. Furthermore, finite population correction to the mean-field results are found to be insignificant.Comment: 4 pages, 2 figures, revised, to appear in Phys. Rev. Let

    ‘Image‘ Kota Goettingen Dan Sekitarnya Sebagai Salah Satu Tujuan Wisata Alam Dan Rekreasi Luar Ruangan (Study Kasus Menurut Mahasiswa Internasional Di Universitas Goettingen)

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    Nature tourism/outdoor recreation is one the fastest growing tourism activities in the world. More and more people travel to natural sites due to increased environmental awareness and a high degree of urbanization.The objective of this research was to capture the image of Göttingen and its surrounding area, using a combination of structured and unstructured methods as recommended by previous researchers. The image determination was considered important for positioning and differentiating the destination from other competitors. From a marketing point of view, image determination could increase tourist interest to visit the destination, travel satisfaction, and intention to return. The structured method used image attributes, which were evaluated using a 5-point Likert scale while the unstructured method used three open-ended questions. In addition, the research was also done to identify the nature of outdoor recreation/nature tourism among International students. The study focused on International students, which have certain characteristics that are different from those of domestic students. Data was taken from January to April 2014. 326 respondents delivered useable responses/data. This research revealed that a combination of structured and unstructured methods was able to capture the underlying image dimension of Göttingenand its surroundings. Considering the high propensity for travelling and previous travel experience of the students, it could be interpreted that International students at Göttingen University are one of the prospective nature tourism markets. Therefore, customized marketing strategy could be applied to attract them

    Temporal and dimensional effects in evolutionary graph theory

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    The spread in time of a mutation through a population is studied analytically and computationally in fully-connected networks and on spatial lattices. The time, t_*, for a favourable mutation to dominate scales with population size N as N^{(D+1)/D} in D-dimensional hypercubic lattices and as N ln N in fully-connected graphs. It is shown that the surface of the interface between mutants and non-mutants is crucial in predicting the dynamics of the system. Network topology has a significant effect on the equilibrium fitness of a simple population model incorporating multiple mutations and sexual reproduction. Includes supplementary information.Comment: 6 pages, 4 figures Replaced after final round of peer revie

    Reconciling the interests of the economic diversification participants in a single-industry town

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    Рассматриваются проблемы согласования интересов участников процесса диверсификации экономики моногорода в процессе управления развитием моногорода на основе реализации стратегии диверсификации. Целью исследования является разработка инструментов гармонизации интересов участников процесса диверсификации экономики моногорода на основе разработки модели полного согласования интересов и сопоставления ее с моделью отдельно взятого моногорода. Методы исследования: системный подход, анализ и синтез, построение множеств согласования интересов с применением диаграммы Эйлера-Венна, методы комбинаторики, построение экономических показателей и рядов динамики, графический метод представления результатов и построения иерархии согласования интересов. Результаты исследования. Представлена модель полного согласования интересов различных групп лиц, в которой отражены сферы возможного пересечения интересов, а также иерархия числа согласуемых интересов. Предложены основные группы участников процесса диверсификации моногорода, а также разграничено понятие участника и роли (функции) участника в данном процессе. Обосновано и определено число множеств в зависимости от числа участников, чьи интересы одновременно согласуются, на примере моногорода Калтан Кемеровской области. На основе предложенной модели построена модель согласования интересов на примере моногорода Калтана. Полученная модель имеет трапециевидную форму, что свидетельствует о достаточно небольшом числе общих согласуемых интересов. Автор приходит к выводу, что в моногороде сформирован треугольник интересов «администрация города - малый бизнес в роли инвестора - вуз», представляющий основу в иерархии согласования интересов моногорода Калтан. Центральное положение при согласовании интересов с прочими участниками занимает исключительно администрация города. На основе данных выводов внесены предложения по направлениям дальнейшего согласования интересов на примере рассматриваемого моногорода.The article explores the problems of reconciling the interests of single-industry towns, a need that arises from the entire process of industry development management through a diversification strategy. The aim of this study is to develop tools to harmonize the interests of the single-industry towns, based on a model of full harmonization with the model of an individual single-industry town. Methods of the research: system approach, analysis and synthesis, building a set of harmonized interests with the application of the Eulerian-Venn diagram, combinatorics methods, construction of economic indicators and series of dynamics, graphical method of presentation of results and building the hierarchy of interests. Results of the study. The paper introduces the model for fully reconciling the interests of different groups of persons, reflecting the areas of possible intersecting interests and the hierarchy of the number of interests involved. The article proposes the main groups of participants in the diversification process and the differentially concept of participant and the role (function) of the participant in the diversification process. The author justifies and estimates the number of sets depending on the number of participants whose interests are concurrently reconciled in Kaltan case study. The proposed model is used for Kaltan, Kemerovo region case study. The result ing model is of a trapezoidal form, which indicates that there are quite a few common consenting interests. The author concludes that a triangle of interests «city administration - small business as investor - university» is formed. This triangle represents the highest level of harmonization of interests in the hierarchy. The city administration is in central position in reconciling interests with other participants. By the example of the considered single-industry town and based on these findings the suggestion on further harmonization of interests was made

    Stochastic slowdown in evolutionary processes

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    We examine birth--death processes with state dependent transition probabilities and at least one absorbing boundary. In evolution, this describes selection acting on two different types in a finite population where reproductive events occur successively. If the two types have equal fitness the system performs a random walk. If one type has a fitness advantage it is favored by selection, which introduces a bias (asymmetry) in the transition probabilities. How long does it take until advantageous mutants have invaded and taken over? Surprisingly, we find that the average time of such a process can increase, even if the mutant type always has a fitness advantage. We discuss this finding for the Moran process and develop a simplified model which allows a more intuitive understanding. We show that this effect can occur for weak but non--vanishing bias (selection) in the state dependent transition rates and infer the scaling with system size. We also address the Wright-Fisher model commonly used in population genetics, which shows that this stochastic slowdown is not restricted to birth-death processes.Comment: 8 pages, 3 figures, accepted for publicatio

    Millimeter-Wave Spectra, ab Initio Calculations, and Structures of Fluorophosphane and Chlorophosphane

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    The structures of fluorophosphane, PH2F, and chlorophosphane, PH2Cl, have been calculated ab initio at the SCF, MP2, CCSD, and CCSD(T) levels using a quadruple ζ polarized basis set. Equilibrium and ground state rotational constants as well as centrifugal distortion constants have been predicted for several isotopomers of PH2F and PH2Cl. Theoretical CCSD(T) geometries were also determined for the series of PHnX3-n (X = F, Cl; n = 0−3) molecules using a triple ζ polarized basis set. The millimeter-wave spectra of the short-lived molecules PH2F, PH2Cl, and their perdeuterated species were measured in the frequency range 100−470 GHz. For PH2F and PH2Cl, accurate ground state parameters have been obtained by a combined fit of the millimeter-wave data and the infrared ground state combination differences. The ro, rz, and re structures of PH2F and PH2Cl, as well as PH3, PCl3, and PHF2 have been determined. The experimental results are found in excellent agreement with their ab initio predictions

    Discharges of past flood events based on historical river profiles

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    International audienceThis paper presents a case study to estimate peak discharges of extreme flood events of Neckar River in south-western Germany during the 19th century. It was carried out within the BMBF research project RIMAX (Risk Management of Extreme Flood Events). The discharge estimations were made for the flood events of 1824 and 1882 based on historical cross profiles. The 1-D model Hydrologic Engineering Centers River Analysis System (HEC-RAS) was applied with different roughness coefficients. The results are compared (i) with contemporary historical calculations and (ii) in the case of a flood event in 1824 with the discharge simulation by the water balance model LARSIM (Large Area Runoff Simulation Model). These calculations are matched by the HEC-RAS simulation based on the standard roughness coefficients

    Fully adaptive multiresolution schemes for strongly degenerate parabolic equations with discontinuous flux

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    A fully adaptive finite volume multiresolution scheme for one-dimensional strongly degenerate parabolic equations with discontinuous flux is presented. The numerical scheme is based on a finite volume discretization using the Engquist--Osher approximation for the flux and explicit time--stepping. An adaptivemultiresolution scheme with cell averages is then used to speed up CPU time and meet memory requirements. A particular feature of our scheme is the storage of the multiresolution representation of the solution in a dynamic graded tree, for the sake of data compression and to facilitate navigation. Applications to traffic flow with driver reaction and a clarifier--thickener model illustrate the efficiency of this method

    Survey of chicken abattoir for the presence of Campylobacter jejuni and Campylobacter coli

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    The genus Campylobacter is of great importance to public health because it includes several species that may cause diarrhea. These species may be found in water, food and in the intestinal tract of chickens. This study investigated the presence of Campylobacter jejuni and Campylobacter coli in chicken abattoirs in São Paulo State, Brazil. A total of 288 samples of feces, feathers, scald water, evisceration water, chiller water, and the rinse water of eviscerated, not eviscerated and chilled carcasses were collected in six chicken abattoirs. Polymerase Chain Reaction (PCR) was performed in Campylobacter spp.-positive isolates using the gene HIP, specific for hippuricase enzyme from Campylobacter jejuni and aspartokinase gene, specific to detect Campylobacter coli. The percentage of positive isolates of Campylobacter jejuni was 4.9% (14/288). Isolation was greater in feces samples (22%, 8/36). One sample was positive for the species C. coli. In conclusion, the results indicate that it is necessary to improve quality control for Campylobacter spp. in chicken abattoirs.O gênero Campylobacter tem grande destaque em saúde pública, principalmente por pertencerem a este gênero várias espécies que podem causar diarréia. Estas espécies podem ser encontradas em amostras de água, alimentos e no trato intestinal das aves. Este estudo investigou a presença de Campylobacter jejuni e Campylobacter coli em abatedouros de aves no Estado de São Paulo. As 288 amostras foram coletadas em seis estabelecimentos e incluíram: fezes; penas; água de escaldamento, de evisceração e de resfriamento; e água de enxaguadura de carcaça não eviscerada, eviscerada e resfriada. Após o isolamento microbiológico das amostras positivas de Campylobacter spp. foi realizada uma Reação em Cadeia da Polimerase (PCR) utilizando o gene HIP, da hipuricase, específico para Campylobacter jejuni e o gene da enzima aspartoquinase, específico para Campylobacter coli. A porcentagem de amostras positivas para Campylobacter spp. foi de 4,9% (14/288), sendo que o isolamento foi maior em amostras de fezes (22%, 8/36). Foi isolada uma amostra positiva para C. coli. Em conclusão, os resultados indicam que há uma necessidade de melhorar a qualidade higiênico-sanitária do controle de Campylobacter em abatedouros de aves
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