117,447 research outputs found
Preliminary Design of the Support Structure for a Rotating Carbon-Ion Transfer Line for Medical Applications
No full textThe development of new bent superconducting magnets together with the optimization of the support structure open the way to a considerable reduction in the weight and complexity of rotating gantries for medical applications. The magnets, which define the transfer line to deliver carbon ions to the patients from different angles, are supported by a rotating structure that should be as rigid and as lightweight as possible. Relative displacements of the magnets due to deformations cause incorrect beam position and consequent errors in hitting the target tissues. This paper describes a possible rotating structure which is considerably lighter than the previous designs. A method to compensate part of the deformation by complementary rotations of the driving motor is proposed. The influence of the construction tolerances and deformations of the supports is also analyzed and alignment and adjustment possibilities are discussed
Etude de la qualité physico-chimique de l’eau de boisson dans deux localités du Bénin: Cotonou et Dassa-Zoumè
No full textL’eau, source potentielle de vie, doit subir diverses analyses physico-chimiques qui définiront sa qualité pour la consommation humaine afin d’éviter les risques de maladies hydriques pour les consommateurs. La présente étude vise à déterminer la qualité physico-chimique de l’eau de boisson des populations de deux villes du Bénin : Dassa-Zoumè et Cotonou. Trois points de prélèvement ont été identifiés dans chacune des deux localités pour un total de six (06) échantillons. Dix-neuf paramètres physico-chimiques ont été évalués sur ces échantillons. Certains paramètres (température, pH, turbidité et conductivité) susceptibles de modification au cours du transport ont été déterminés "in situ". Les résultats obtenus ont montré que l’eau des deux localités que consomment les populations est de bonne qualité sur le plan physico-chimique. Néanmoins, l’eau de consommation des populations de Dassa est plus alcaline et plus dure que celle de Cotonou : soit respectivement de 390 à 480 mg/l et de 25 à 35 mg/l puis de 232 à 260 mg/l et de 15 à 27 mg/l. Ce constat pourrait expliquer le caractère moins moussant et le goût terne souvent remarqués au niveau de l’eau de Dassa et serait lié à la nature géologique des sols traversés.© 2016 International Formulae Group. All rights reservedMots clés: Qualité physico-chimique, eau de boisson, BéninEnglish Title: Study of the physico-chemical quality of drinking water in two localities of Benin: Cotonou and Dassa-ZoumèEnglish AbstractWater, potential source of life, must undergo various physico-chemical analyzes that will define its quality for human consumption in order to avoid the risk of water-borne diseases to consumers. The present study aims to determine the physico-chemical quality of population’s drinking water in two cities of Benin: Cotonou and Dassa-Zoume. Three sampling points were identified in each of the two localities for a total of six (06) samples. Nineteen physico-chemical parameters were evaluated on these samples. Some parameters (temperature, pH, turbidity and conductivity) which may be modified during transport were determined "in situ". The results showed that the water consumed by the populations of both localities has a good physicochemical quality. Nevertheless, drinking water of Dassa’s populations was more alkaline and harder than that of Cotonou: respectively 390-480 mg/l and 232-260 mg/l for Dassa and then 25-35 mg/l and 15-17 mg/l for Cotonou. This finding may explain the less foaming character and dull taste often noticed in Dassa's water and would be linked to the geological nature of the soils traversed.© 2016 International Formulae Group. All rights reservedKeywords: Physico-chemical quality, drinking water, Beni
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
Geochronology and geochemistry of igneous rocks of the Dassa region, Central-Benin: evidence of an Ediacaran emplacement of alkali-calcic and alkaline plutonic and volcanic magmas
No full textInternational audienceThe Dassa region is part of the Pan-African Trans-Saharan Belt, located between the West African craton and the Sahara metacraton. This region, with widespread granitoids and volcanites, is cut by the Kandi Shear Zone (KSZ) that could be connected to the 4°50' shear zone northwards in the Hoggar mountains and to the "Transbrasiliano lineamento" Northeast Brazil. The LA-ICP-MS U-Pb isotopes of zircon, whole-rock geochemistry and Sr-Nd isotope were analysed to constrain the emplacement ages and chronology of granitoids and volcanic rocks in the Dassa region in relation to the KSZ dynamics and the geochemical signatures and genesis of the magmas. Five intrusions (Dassa, Tré, Gobada, Tchetti and Fita) with the igneous rocks of the volcano-sedimentary basin of Idaho-Mahou have been investigated. Radiometric ages (U-Pb) obtained on zircons from the intrusions and the alkaline rhyolites from the Idaho-Mahou volcano-sedimentary basin indicate the Ediacaran timing emplacement in the Pan-African Dahomeyide orogen. The Dassa intrusion is dated at 633 ± 19 Ma while the Tchetti, Gobada and Tré intrusions yield 607 ± 11 Ma, 603 ± 10 Ma and 595 ± 12 Ma, respectively. The alkaline Fita granite and rhyolite of the Idaho-Mahou volcano-sedimentary basin provide U-Pb on zircon ages of 594 ± 32 Ma and 583 ± 9 Ma, respectively. Geochemical investigations reveal that the granitoids are ferroan and metaluminous; alkali-calcic (Dassa and Tré) and alkali-calcic to alkalic (Gobada, Tchetti and Fita). The mafic to intermediate volcanites and trachyte of Idaho-Mahou volcano-sedimentary basin are alkali-calcic whereas the rhyolite displays an alkalic signature. Sm-Nd isotopic analyses reveal that the ε Nd values at c. 600 Ma in the Fita granite and alkalic rhyolite of Idaho-Mahou basin are the highest (− 6.94 and − 6.07). In the other intrusions, the ε Nd values at c. 600 Ma are lower, ranging between − 9.66 and − 9.28 (Tchetti and Godada granites) and − 8.84 and − 8.56 (Dassa and Tré granites). The Tré monzonite shows an intermediate value around − 7.70. The calculated TDM model ages are very close and range between 1.80 and 2.05 Ga. All this suggests hybridization processes between an Archean to Paleoproterozoic continental crust source and a juvenile mantle (600 Ma) source for the parent magmas. But the significantly high ε Nd values of Fita granite and the alkaline rhyolite are in agreement with higher mantle contribution and a distinct more enriched mantle source for the parent magmas of alkaline rocks compared to the alkali-calcic felsic ones for which the mantle contribution is from the depleted mantle. According to these data, the Ediacaran magmatic events in the Dassa region can be divided into two main episodes with respect to the main transcurrent shearing event that started at about c. 610 Ma: a pre-transcurrent shear alkali-calcic plutonic magmatism c. 635-610 Ma and the transcurrent shear magmatism c. 610-580 Ma with contemporaneous alkali-calcic and alkaline plutonic and volcanic magmatism. The integration of existing U-Pb on zircon dating in the Benin basement indicates that in the Dahomeyide orogen, the reactivation of the Kandi shear zone toward the end of Ediacaran timing at around c. 550-540 Ma allowed emplacement of the third suite of magmatism as intrusions and volcanoes
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
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
In situ compact tensile test device for polymer nanocomposite specimens to be analyzed in an x-ray microdiffractometer
No full textX-ray diffraction is a non-destructive technique for structural analysis of materials. Applications include the evaluation of the residual stresses in real components, wherein the crystalline planes are used as strain gauges. In case of polymer nanocomposites, this technique allows to study the filler structural changes, in particular its orientation as a function of polymer deformation.
A tensile test device to apply uniaxial stretching on polymer nanocomposite specimens has been designed and built to equip a commercial X-ray microdiffractometer.
The main feature of this compact device is allowing setting the specimen strain up to 400% inside the microdiffractometer. X-ray diffraction measurements are carried out at different strains at the same point without removing the sample from the stage. The maximum load applied to the specimen is 100 N.
We report the design phases and the results of preliminary tests on commercial rubber samples
Sarah L. Blum Author Visit - Warrior Nurse: PTSD and Healing
No full textHear Sarah L. Blum, author of Women Under Fire: Abuse in the Military, discuss her newest book, Warrior Nurse: PTSD and Healing followed by a Q&A and book signing.
Sarah L. Blum is a decorated Vietnam veteran who served as an operating room nurse during the intense fighting of 1967. In recognition of her service, she was awarded the Army Commendation Medal.
Sponsored by CWU Veterans Center and CWU Libraries.https://digitalcommons.cwu.edu/libraryevents/1252/thumbnail.jp
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