Chemical News and Journal of physical science

CHEMICAL NEWS AND JOURNAL OF PHYSICAL SCIENCE Chemical News and Journal of physical science (-) Chemical News and Journal of physical science (Volume 35, 1877 (January - June)) (-) Titelseite (-) No. 893 (January 5, 1877) ([1]) No. 894 (January 12, 1877) (13) No. 895 (January 19, 1877) (23) No. 896 (January 26, 1877) (35) No. 897 (Febuary 2, 1877) (45) No. 898 (Febuary 9, 1877) (57) No. 899 (Febuary 16,1877) (67) No. 900 (Febuary 23,1877) (77) No. 901 (March 2, 1877) (87) No. 902 (March 9, 1877) (97) No. 903 (March 16, 1877) (107) No. 904 (March 23, 1877) (117) No. 905 (March 29, 1877) (127) No. 906 (April 6, 1877) (137) No. 907 (April 13, 1877) (147) No. 908 (April 20, 1877) (157) No. 909 (April 27, 1877) (167) No. 910 (May 4, 1877) (179) No. 911 (May 11, 1877) (189) No. 912 (May 18, 1877) (201) No. 913 (May 25, 1877) (211) No. 914 (June 1, 1877) (223) No. 915 (June 8, 1877) (233) No. 916 (June 15, 1877) (245) No. 917 (June 22, 1877) (255) No. 918 (June 29, 1877) (267) Index (Volume 35) (279) Graukeil (-

Some Possibilities of Electricity

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El tubo de rayos catódicos, o tubo de Crookes por el nombre de su inventor, consiste en una ampolla de vacío fabricada en vidrio en la que se dispone un filamento caliente o cátodo que emite electrones (efecto Edison o termoiónico) cuya trayectoria puede modificarse mediante las fuerzas asociadas a campos eléctricos y/o magnéticos. En el interior de la ampolla se deposita una sustancia fosforescente de forma que cuando los electrones chocan con ella se visualiza el impacto como un punto luminoso de breve duración, como en una antigua pantalla de TV o monitor de un ordenador. Algunas variantes en el diseño del tubo permiten estudiar la difracción de electrones, la electroluminiscencia, las trayectoria de electrones sometidos a campos E y B cruzados... lo que hace de este aparato una ayuda inestimable para la explicación de la física elemental de balística de partículas.Tamaño (altoxlargoxancho):31.5x20.5x4 cmEl modelo de tubo de rayos catódicos que presentamos aquí corresponde a un triodo planar de vacío Teltron 521 formado por cátodo y ánodo y una rejilla entre ellos. Se trata de una ampolla de vacío en la que se ha depositado en su parte interior una fina capa metálica para eliminar efectos electrostáticos externos. El filamento de wolframio se calienta con alimentación de 6,3 V y se añade un electrodo circular con agujeros conectado a uno de los bornes del filamento a fin de conseguir un campo eléctrico más uniforme. El ánodo o placa es otro disco circular y también la rejilla está realizada sobre un disco metálico de forma que los tres electrodos paralelos forman una estructura planar. El potencial del ánodo es del orden de 500 V y la corriente de aproximadamente 0,35 mA. Si la diferencia de potencial entre rejilla y cátodo es nula tenemos un simple diodo en el que midiendo la corriente de placa conectada a un potencial determinado y atendiendo a la polaridad de la corriente concluimos que los portadores de carga salientes del filamento son de carga negativa, es decir, electrones. Si operamos con la rejilla observaremos cómo la corriente de placa crece cuando la rejilla es positiva y decrece cuando es negativa, lo que confirma la carga negativa de los rayos catódicos. Además notaremos que pequeñas variaciones del potencial de rejilla dan lugar a grandes cambios en la corriente anódica, lo que sugiere emplear el tubo como amplificador de señales eléctricas. Así pues, tenemos un dispositivo que se comporta sin rejilla como un simple diodo rectificador pues solo conduce cuando el potencial de placa es positivo frente al filamento y además puede operar como triodo amplificador de la señal aplicada a la rejilla permitiendo construir circuitos de interés como por ejemplo el oscilador

Holistic processing, contact, and the other-race effect in face recognition

Face recognition, holistic processing, and processing of configural and featural facial information are known to be influenced by face race, with better performance for own- than other-race faces. However, whether these various other-race effects (OREs) arise from the same underlying mechanisms or from different processes remains unclear. The present study addressed this question by measuring the OREs in a set of face recognition tasks, and testing whether these OREs are correlated with each other. Participants performed different tasks probing (1) face recognition, (2) holistic processing, (3) processing of configural information, and (4) processing of featural information for both own- and other-race faces. Their contact with other-race people was also assessed with a questionnaire. The results show significant OREs in tasks testing face memory and processing of configural information, but not in tasks testing either holistic processing or processing of featural information. Importantly, there was no cross-task correlation between any of the measured OREs. Moreover, the level of other-race contact predicted only the OREs obtained in tasks testing face memory and processing of configural information. These results indicate that these various cross-race differences originate from different aspects of face processing, in contrary to the view that the ORE in face recognition is due to cross-race differences in terms of holistic processing

How well do computer-generated faces tap face expertise?

The use of computer-generated (CG) stimuli in face processing research is proliferating due to the ease with which faces can be generated, standardised and manipulated. However there has been surprisingly little research into whether CG faces are processed in the same way as photographs of real faces. The present study assessed how well CG faces tap face identity expertise by investigating whether two indicators of face expertise are reduced for CG faces when compared to face photographs. These indicators were accuracy for identification of own-race faces and the other-race effect (ORE)-the well-established finding that own-race faces are recognised more accurately than other-race faces. In Experiment 1 Caucasian and Asian participants completed a recognition memory task for own- and other-race real and CG faces. Overall accuracy for own-race faces was dramatically reduced for CG compared to real faces and the ORE was significantly and substantially attenuated for CG faces. Experiment 2 investigated perceptual discrimination for own- and other-race real and CG faces with Caucasian and Asian participants. Here again, accuracy for own-race faces was significantly reduced for CG compared to real faces. However the ORE was not affected by format. Together these results signal that CG faces of the type tested here do not fully tap face expertise. Technological advancement may, in the future, produce CG faces that are equivalent to real photographs. Until then caution is advised when interpreting results obtained using CG faces

Radiant matter

42 σ., εικ.Δωρεά Ι. Δοανίδη (αρ. 1178/1954)Aνατύπωσις εκ του Ι' τόμου του Αθηναίο

Holistic processing for other-race faces in Chinese participants occurs for upright but not inverted faces

Recent evidence suggests stronger holistic processing for own-race faces may underlie the own-race advantage in face memory. In previous studies Caucasian participants have demonstrated larger holistic processing effects for Caucasian over Asian faces. However, Asian participants have consistently shown similar sized effects for both Asian and Cau- casian faces. We investigated two proposed explanations for the holistic processing of other-race faces by Asian participants: (1) greater other-race exposure, (2) a general global processing bias. Holistic processing was tested using the part-whole task. Participants were living in predominantly own-race environments and other-race contact was evalu- ated. Despite reporting significantly greater contact with own-race than other-race people, Chinese participants displayed strong holistic processing for both Asian and Caucasian upright faces. In addition, Chinese participants showed no evidence of holistic processing for inverted faces arguing against a general global processing bias explanation. Caucasian participants, in line with previous studies, displayed stronger holistic processing for Cau- casian than Asian upright faces. For inverted faces there were no race-of-face differences. These results are used to suggest that Asians may make more general use of face-specific mechanisms than Caucasians. This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permission

A practical handbook of dyeing and calico-printing

by William Crooke

[Letters to Editor]

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