24,047 research outputs found

    Alcoa wind turbines

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    An overview of Alcoa's wind energy program is given with emphasis on the the development of a low cost, reliable Darrieus Vertical Axis Wind Turbine System. The design layouts and drawings for fabrication are now complete, while fabrication and installation to utilize the design are expected to begin shortly

    A Computer Method for Calculation of the Complete and Incomplete Elliptic Integrals of the Third Kind

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    Numerical approximations and a Fortran IV program are given for the calculation by an IBM 7090 computer of the complete and incomplete elliptic integrals of the third kind. In its present form results are limited to six decimal places, but the method is valid for all values of amplitude φ, modulus k and real values of the parameter a^2. For the purpose of completeness, adaptations of other programs for complete and incomplete elliptic integrals of the first and second kind are also presented

    Constructing solutions to the Bj\"orling problem for isothermic surfaces by structure preserving discretization

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    In this article, we study an analog of the Bj\"orling problem for isothermic surfaces (that are more general than minimal surfaces): given a real analytic curve γ\gamma in R3{\mathbb R}^3, and two analytic non-vanishing orthogonal vector fields vv and ww along γ\gamma, find an isothermic surface that is tangent to γ\gamma and that has vv and ww as principal directions of curvature. We prove that solutions to that problem can be obtained by constructing a family of discrete isothermic surfaces (in the sense of Bobenko and Pinkall) from data that is sampled along γ\gamma, and passing to the limit of vanishing mesh size. The proof relies on a rephrasing of the Gauss-Codazzi-system as analytic Cauchy problem and an in-depth-analysis of its discretization which is induced from the geometry of discrete isothermic surfaces. The discrete-to-continuous limit is carried out for the Christoffel and the Darboux transformations as well.Comment: 29 pages, some figure

    On a new conformal functional for simplicial surfaces

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    We introduce a smooth quadratic conformal functional and its weighted version W2=∑eβ2(e)W2,w=∑e(ni+nj)β2(e),W_2=\sum_e \beta^2(e)\quad W_{2,w}=\sum_e (n_i+n_j)\beta^2(e), where β(e)\beta(e) is the extrinsic intersection angle of the circumcircles of the triangles of the mesh sharing the edge e=(ij)e=(ij) and nin_i is the valence of vertex ii. Besides minimizing the squared local conformal discrete Willmore energy WW this functional also minimizes local differences of the angles β\beta. We investigate the minimizers of this functionals for simplicial spheres and simplicial surfaces of nontrivial topology. Several remarkable facts are observed. In particular for most of randomly generated simplicial polyhedra the minimizers of W2W_2 and W2,wW_{2,w} are inscribed polyhedra. We demonstrate also some applications in geometry processing, for example, a conformal deformation of surfaces to the round sphere. A partial theoretical explanation through quadratic optimization theory of some observed phenomena is presented.Comment: 14 pages, 8 figures, to appear in the proceedings of "Curves and Surfaces, 8th International Conference", June 201

    Efficiency optimization in a correlation ratchet with asymmetric unbiased fluctuations

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    The efficiency of a Brownian particle moving in periodic potential in the presence of asymmetric unbiased fluctuations is investigated. We found that there is a regime where the efficiency can be a peaked function of temperature, which proves that thermal fluctuations facilitate the efficiency of energy transformation, contradicting the earlier findings (H. kamegawa et al. Phys. Rev. Lett. 80 (1998) 5251). It is also found that the mutual interplay between asymmetry of fluctuation and asymmetry of the potential may induce optimized efficiency at finite temperature. The ratchet is not most efficiency when it gives maximum current.Comment: 10 pages, 7 figure

    Rabies elimination research: juxtaposing optimism, pragmatism and realism

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    More than 100 years of research has now been conducted into the prevention, control and elimination of rabies with safe and highly efficacious vaccines developed for use in human and animal populations. Domestic dogs are a major reservoir for rabies, and although considerable advances have been made towards the elimination and control of canine rabies in many parts of the world, the disease continues to kill tens of thousands of people every year in Africa and Asia. Policy efforts are now being directed towards a global target of zero human deaths from dog-mediated rabies by 2030 and the global elimination of canine rabies. Here we demonstrate how research provides a cause for optimism as to the feasibility of these goals through strategies based around mass dog vaccination. We summarize some of the pragmatic insights generated from rabies epidemiology and dog ecology research that can improve the design of dog vaccination strategies in low- and middle-income countries and which should encourage implementation without further delay. We also highlight the need for realism in reaching the feasible, although technically more difficult and longer-term goal of global elimination of canine rabies. Finally, we discuss how research on rabies has broader relevance to the control and elimination of a suite of diseases of current concern to human and animal health, providing an exemplar of the value of a ‘One Health’ approach

    Pendekatan Komunikatif Interaktif untuk Meningkatkan Kosakata Anak Usia Dini

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    Penelitian ini dilatarbelakangi karena adanya masalah bahasa khususnya kosa kata. Masalah tersebut yakni kurang mampu mengkomunikasikan apa yang dilihat, dirasa dan didengar, kurang mampu mengekspresikan perasaan dengan menggunakan kata-kata. Subjek penelitian sebanyak 15 anak, yang terdiri dari 6 anak laki-laki dan 9 anak perempuan. Tujuan penelitian tersebut adalah (1) untuk meningkatkan pemerolehan kosakata pada anak usia dini dengan menggunakan pendekatan komunikatif interaktif, (2) untuk mengetahui hasil penggunaan pendekatan komunikatif interaktif dalam meningkatkan pemerolehan kosakata pada anak usia dini. Kegiatan yang dilaksanakan yaitu bercerita, bercakap- cakap, menceritakan gambar, melihat video pembelajaran, bermain peran dan permainan yang didalamnya terjadi proses interaksi, peserta dengan peserta didik maupun peserta didik dengan peneliti. Metode penelitian ini menggunakan Penelitian Tindakan Kelas (PTK) dengan model Elliot, yakni terdiri dari 3 siklus dan 9 tindakan. Teknik pengumpulan data menggunakan beberapa teknik yakni observasi guru, observasi anak, wawancara anak, catatan lapangan dan dokumentasi. Hasil penelitian melalui pendekatan komunikatif interaktif dapat meningkatkan kosakata pada anak, hal tersebut dapat dilihat dari hasil yang diperoleh. Hasil penelitian ini yaitu pada siklus 1 rata-rata kelas sebesar 1,66, siklus 2 rata-rata kelas meningkat menjadi 2,12 dan pada siklus 3 rata-rata kelas meningkat menjadi 3. Diharapkan semua pihak sadar pentingnya pencapaian kemampuan bahasa pada anak, karena dengan optimalnya perkembangan bahasa pada anak, maka aspek perkembangan lainnya pun berkembang secara optimal pula

    Temporal patterns in the recorded annual incidence of common mental disorders over two decades in the United Kingdom: a primary care cohort study

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    BACKGROUND: Common mental disorders (CMDs) including depression, anxiety, and stress are very common, but it is unclear whether the last decades of social, economic, and political change have impacted incidence of CMD. This study explored temporal trends in the recorded incidence of CMD in the United Kingdom. METHODS: We used data from general practices in the United Kingdom (Clinical Practice Research Datalink) to estimate the annual recorded incidence of CMD for 2000-2020, including symptoms, diagnosis, or pharmaceutical treatment. Trends were explored by sex, age, ethnicity, region, deprivation, and comorbidity. RESULTS: We included 29 480 164 individuals who were followed up for 12.5 years on average (s.d. = 6.4 years). The recorded incidence of CMD episodes was 55.9 per 1000 person-years in 2000 [95% confidence interval (CI) 55.8-56.1], increasing to 79.6 per 1000 person-years in 2019 (95% CI 79.5-79.8). Females had higher recorded incidence rates, as did those living in more deprived areas. We observed striking patterns by age over time, with rates in ages 16-24 increasing from 40.2 per 1000 in 2000 (95% CI 39.8-40.5), to 107.8 per 1000 in 2019 (95% CI 107.0-108.6). In contrast, the rates in those aged ≥55 years decreased since 2014. There were differing patterns of incidence by ethnic group, with a steeper increase in Asian, Black, and mixed groups in recent years. CONCLUSIONS: Overall, the incidence of recorded CMD in the UK general practice increased between 2000 and 2019 with a small decrease in 2020. The overall trends obscured important differences across population subgroups, which may have implications for prevention

    Temporal patterns in the recorded annual incidence of common mental disorders over two decades in the United Kingdom: a primary care cohort study

    Get PDF
    BACKGROUND: Common mental disorders (CMDs) including depression, anxiety, and stress are very common, but it is unclear whether the last decades of social, economic, and political change have impacted incidence of CMD. This study explored temporal trends in the recorded incidence of CMD in the United Kingdom. METHODS: We used data from general practices in the United Kingdom (Clinical Practice Research Datalink) to estimate the annual recorded incidence of CMD for 2000-2020, including symptoms, diagnosis, or pharmaceutical treatment. Trends were explored by sex, age, ethnicity, region, deprivation, and comorbidity. RESULTS: We included 29 480 164 individuals who were followed up for 12.5 years on average (s.d. = 6.4 years). The recorded incidence of CMD episodes was 55.9 per 1000 person-years in 2000 [95% confidence interval (CI) 55.8-56.1], increasing to 79.6 per 1000 person-years in 2019 (95% CI 79.5-79.8). Females had higher recorded incidence rates, as did those living in more deprived areas. We observed striking patterns by age over time, with rates in ages 16-24 increasing from 40.2 per 1000 in 2000 (95% CI 39.8-40.5), to 107.8 per 1000 in 2019 (95% CI 107.0-108.6). In contrast, the rates in those aged ≥55 years decreased since 2014. There were differing patterns of incidence by ethnic group, with a steeper increase in Asian, Black, and mixed groups in recent years. CONCLUSIONS: Overall, the incidence of recorded CMD in the UK general practice increased between 2000 and 2019 with a small decrease in 2020. The overall trends obscured important differences across population subgroups, which may have implications for prevention

    Vanishing cycles and mutation

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    This is the writeup of a talk given at the European Congress of Mathematics, Barcelona. It considers Picard-Lefschetz theory from the Floer cohomology viewpoint.Comment: 20 pages, LaTeX2e. TeXnical problem should now be fixed, so that the images will appear even if you download the .ps fil
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