11,623 research outputs found

    Limited Range Fractality of Randomly Adsorbed Rods

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    Multiple resolution analysis of two dimensional structures composed of randomly adsorbed penetrable rods, for densities below the percolation threshold, has been carried out using box-counting functions. It is found that at relevant resolutions, for box-sizes, rr, between cutoffs given by the average rod length and the average inter-rod distance $r_1$, these systems exhibit apparent fractal behavior. It is shown that unlike the case of randomly distributed isotropic objects, the upper cutoff $r_1$ is not only a function of the coverage but also depends on the excluded volume, averaged over the orientational distribution. Moreover, the apparent fractal dimension also depends on the orientational distributions of the rods and decreases as it becomes more anisotropic. For box sizes smaller than the box counting function is determined by the internal structure of the rods, whether simple or itself fractal. Two examples are considered - one of regular rods of one dimensional structure and rods which are trimmed into a Cantor set structure which are fractals themselves. The models examined are relevant to adsorption of linear molecules and fibers, liquid crystals, stress induced fractures and edge imperfections in metal catalysts. We thus obtain a distinction between two ranges of length scales: rr where the internal structure of the adsorbed objects is probed, and <r<r1 < r < r_1 where their distribution is probed, both of which may exhibit fractal behavior. This distinction is relevant to the large class of systems which exhibit aggregation of a finite density of fractal-like clusters, which includes surface growth in molecular beam epitaxy and diffusion-limited-cluster-cluster-aggregation models.Comment: 10 pages, 7 figures. More info available at http://www.fh.huji.ac.il/~dani/ or http://www.fiz.huji.ac.il/staff/acc/faculty/biham or http://chem.ch.huji.ac.il/employee/avnir/iavnir.htm . Accepted for publication in J. Chem. Phy

    Hodge numbers for the cohomology of Calabi-Yau type local systems

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    We use Higgs cohomology to determine the Hodge numbers of the first intersection cohomology group of a local system V arising from the third direct image of a family of Calabi-Yau 3-folds over a smooth, quasi-projective curve. We give applications to Rhode's families of Calabi-Yau 3-folds without MUM.Comment: Some signs corrected. This article draws heavily from arXiv:0911.027

    R Function Related to Entanglement of Formation

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    By investigating the convex property of the function R, appeared in computing the entanglement of formation for isotropic states in Phys. Rev. Lett. 85, 2625 (2000), and a tight lower bound of entanglement of formation for arbitrary bipartite mixed states in Phys. Rev. Lett. 95, 210501 (2005), we show analytically that the very nice results in these papers are valid not only for dimensions 2 and 3 but any dimensions.Comment: 3 page

    The Effect of Pre-Interview Training and Warnings on Children\u27s Eyewitness Testimonies

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    The present study examined two important issues regarding children\u27s eyewitness testimonies -compliance which is the tendency to agree with misleading questions and the misinformation effect whereby participants incorporate misleading postevent information into their memory recall of the original event. Eighty six primary school children (6-8 years) watched a video, listened to a misleading narrative and were then interviewed individually. To reduce compliance half the children received a pre-interview training package composed of instructions and practice questions with \u27neither\u27 and \u27don\u27t know\u27 response options. To reduce the misinformation effect children were given a warning that they may have heard some misleading information. The test consisted of five misleading questions, five nonmisleading questions, five control questions and five misled questions. Results indicated that pre-interview training did reduce compliance to misleading questions, however there was also a decrease in correct responses to nonmisleading questions. This may be due to an overgeneralisation of the \u27don\u27t know\u27 and \u27neither\u27 options or a reflection of the high rate of guessing. There was a misinformation effect, indicating that the children did incorporate the misleading information into their answers. The warning did not reduce the misinformation effect for children in the experimental group. This may be due to a lack of cognitive abilities to retrieve the original information and the demand characteristics of the interview situation. A number of explanations for the findings of the study are discussed. Further research would be beneficial investigating ways of improving children\u27s accuracy and reliability when providing eyewitness testimonies

    Site Amplification Studies for NPP Sites in Switzerland within the Project Pegasos and PRP

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    Based on a request by ENSI (Nuclear Regulatory Authority of Switzerland) to update the existing probabilistic earthquake hazard studies, Swissnuclear, the association of the nuclear power plants in Switzerland, initiated the PEAGASOS Project. The project started in 2001 and finished in 2004. It is for Europe a unique study, which aimed to evaluate uncertainties systematically and comprehensively. It was decided to perform the study on SSHAC-level 4. Level 4, defined by the Senior Seismic Hazard-Committee, is the highest level and was used only once before for the Yucca-Mountain-Project in the USA. In the PEGASOS Project, 21 international experts from Europe and additional supporting experts and companies from US and Europe were involved. The project was divided in 4 sub-projects representing the different steps in a seismic hazard assessment, namely seismic source characterization, attenuation relationships models, site amplification and seismic hazard calculation. ENSI closely accompanied and reviewed the project. It concluded that PEGASOS project fulfilled the requirements of a level-4-study. The assessment of site-effects and the innovative quality assurance program has set a new benchmark in seismic hazard assessment. The results have been based on the latest state of knowledge and are the best basis to assess the seismic hazard at the four nuclear power plant sites in Switzerland. It also noticed that the derived uncertainties were remarkably large and could probably be reduced by further investigations. The best candidates for reduction of uncertainties were identified in the area of attenuation models and in the site conditions studies. Therefore Swissnuclear initiated the PEGASOS Refinement Project (PRP). The paper describes in brief the project structure of the PEGASOS and the PRP, the methodology, the sensitivities of the results and the main findings. It discusses the experiences and the lessons learned by one of the site experts. The paper is mainly based on PEGASOS (2004) where more detailed information can be found

    Comparative Morphology of the Penis and Clitoris in Four Species of Moles (Talpidae).

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    The penile and clitoral anatomy of four species of Talpid moles (broad-footed, star-nosed, hairy-tailed, and Japanese shrew moles) were investigated to define penile and clitoral anatomy and to examine the relationship of the clitoral anatomy with the presence or absence of ovotestes. The ovotestis contains ovarian tissue and glandular tissue resembling fetal testicular tissue and can produce androgens. The ovotestis is present in star-nosed and hairy-tailed moles, but not in broad-footed and Japanese shrew moles. Using histology, three-dimensional reconstruction, and morphometric analysis, sexual dimorphism was examined with regard to a nine feature masculine trait score that included perineal appendage length (prepuce), anogenital distance, and presence/absence of bone. The presence/absence of ovotestes was discordant in all four mole species for sex differentiation features. For many sex differentiation features, discordance with ovotestes was observed in at least one mole species. The degree of concordance with ovotestes was highest for hairy-tailed moles and lowest for broad-footed moles. In relationship to phylogenetic clade, sex differentiation features also did not correlate with the similarity/divergence of the features and presence/absence of ovotestes. Hairy-tailed and Japanese shrew moles reside in separated clades, but they exhibit a high degree of congruence. Broad-footed and hairy-tailed moles reside within the same clade but had one of the lowest correlations in features and presence/absence of ovotestes. Thus, phylogenetic affinity and the presence/absence of ovotestes are poor predictors for most sex differentiation features within mole external genitalia

    Surface charging of thick porous water ice layers relevant for ion sputtering experiments

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    We use a laboratory facility to study the sputtering properties of centimeter-thick porous water ice subjected to the bombardment of ions and electrons to better understand the formation of exospheres of the icy moons of Jupiter. Our ice samples are as similar as possible to the expected moon surfaces but surface charging of the samples during ion irradiation may distort the experimental results. We therefore monitor the time scales for charging and dis- charging of the samples when subjected to a beam of ions. These experiments allow us to derive an electric conductivity of deep porous ice layers. The results imply that electron irradiation and sputtering play a non-negligible role for certain plasma conditions at the icy moons of Jupiter. The observed ion sputtering yields from our ice samples are similar to previous experiments where compact ice films were sputtered off a micro-balance.Comment: arXiv admin note: text overlap with arXiv:1509.0400

    Verification of CPT-invariance of QED bound states for the production of muonium or antimuonium in scattering of electrons or positrons by nuclei

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    A possibility of a verification of CPT-invariance of QED for bound states by example of muonium or antimuonium produced in reactions of scattering of electrons or positrons by nuclei is considered. The number of events of the muonium production is estimated for contemporary accelerators. The method of the detection of muonium by measuring of oscillations of the decay curve caused by the interference between the ground and excited state of muonium is suggested. The admixture of the excited muonium to the final state is calculated.Comment: 7 pages, 3 figures, Latex, published in JETP 74, 196 (2001), corrected mistypes in eqs. (2.2), (2.4), (2.7

    Transport and thermoelectric properties of the LaAlO3_3/SrTiO3_3 interface

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    The transport and thermoelectric properties of the interface between SrTiO3_3 and a 26-monolayer thick LaAlO3_3-layer grown at high oxygen-pressure have been investigated at temperatures from 4.2 K to 100 K and in magnetic fields up to 18 T. For T>T> 4.2 K, two different electron-like charge carriers originating from two electron channels which contribute to transport are observed. We probe the contributions of a degenerate and a non-degenerate band to the thermoelectric power and develop a consistent model to describe the temperature dependence of the thermoelectric tensor. Anomalies in the data point to an additional magnetic field dependent scattering.Comment: 7 pages, 4 figure
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