119,283 research outputs found
Surface Tension and Lindemann Frequency
No full textAssuming as in the theory of liquid viscosity by Andrade that the molecules
of a liquid at its melting-point continue to oscillate with Lindemann frequency v, the surface tension γ of a liquid is here considered to be given by the energy of the oscillating molecules in unit arm of its surface of unimolecular thickness. The relation to which this assumption
leads, viz,. = k2mv2 where m is the mass of the atom or molecule, has been examined in the light of available data for forty five substances including elements and compounds; and it is found that the constant k has a mean value 2°34. Experimental results, which show that viscosity influences the rotational “ wings " in light-scattering, necessitate a
view-point of viscosity independent of relative motion; assuming tentatively that the total momentum transferred per oscillation by the molecules across unit area gives the value of viscosity, and
inserting the value of k obtained from surface tension data therein, Andrade’s expression for viscosity is shown to follow quantitatively. The variation of surface tension with temperature is explained on the basis of Macleod’s relations; several empirical relations requiring verification
have been obtained
Marilee Lindemann, Willa Cather: Queering America
No full textRobinson Christopher L. Marilee Lindemann, Willa Cather: Queering America. In: Revue Française d'Etudes Américaines, N°85, juin 2000. L'invention de l'ordinaire. pp. 122-124
Marilee Lindemann, Willa Cather: Queering America
No full textRobinson Christopher L. Marilee Lindemann, Willa Cather: Queering America. In: Revue Française d'Etudes Américaines, N°85, juin 2000. L'invention de l'ordinaire. pp. 122-124
Da Lambert a Lindemann ed oltre: quant’è difficile “capire” π?
No full textIl seminario, svolto in occasione del Pi Day del 2013, illustra sinteticamente i due risultati fondamentali per la “compren- sione” di π: la sua irrazionalità (Lambert, 1768) e, successivamente, la sua trascendenza (Lindemann, 1882). L’enfasi è posta sui mutamenti delle idee e dei metodi che spesso sono necessari in matematica per risolvere i problemi difficili, e che sono particolarmente rilevanti nel caso dei problemi posti dalla “natura” di
Texture dependence of motion sensing and free flight behavior in blowflies
No full textLindemann JP, Egelhaaf M. Texture dependence of motion sensing and free flight behavior in blowflies. Frontiers in Behavioral Neuroscience. 2013;6:92.Many flying insects exhibit an active flight and gaze strategy: purely translational flight segments alternate with quick turns called saccades. To generate such a saccadic flight pattern, the animals decide the timing, direction, and amplitude of the next saccade during the previous translatory intersaccadic interval. The information underlying these decisions is assumed to be extracted from the retinal image displacements (optic flow), which scale with the distance to objects during the intersaccadic flight phases. In an earlier study we proposed a saccade-generation mechanism based on the responses of large-field motion-sensitive neurons. In closed-loop simulations we achieved collision avoidance behavior in a limited set of environments but observed collisions in others. Here we show by open-loop simulations that the cause of this observation is the known texture-dependence of elementary motion detection in flies, reflected also in the responses of large-field neurons as used in our model. We verified by electrophysiological experiments that this result is not an artifact of the sensory model. Already subtle changes in the texture may lead to qualitative differences in the responses of both our model cells and their biological counterparts in the fly's brain. Nonetheless, free flight behavior of blowflies is only moderately affected by such texture changes. This divergent texture dependence of motion-sensitive neurons and behavioral performance suggests either mechanisms that compensate for the texture dependence of the visual motion pathway at the level of the circuits generating the saccadic turn decisions or the involvement of a hypothetical parallel pathway in saccadic control that provides the information for collision avoidance independent of the textural properties of the environment
Grundfragen und aktuelle Herausforderungen der ärztlichen Sterbebegleitung aus philosophischer Sicht
No full textStoecker R. Grundfragen und aktuelle Herausforderungen der ärztlichen Sterbebegleitung aus philosophischer Sicht. In: Eidam L, Lindemann M, eds. Grundfragen und aktuelle Herausforderungen der ärztlichen Sterbebegleitung. Schriften zum Medizinstrafrecht. Vol 10. 1st ed. Baden-Baden: Nomos Verlag; 2019: 103-116
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
- …
