Search results for "Cone"
showing 10 items of 772 documents
Physicochemical Surface Properties of Various Intraocular Lenses
2001
<i>Purpose:</i> It is of major interest to understand how intraocular lens (IOL) surfaces interact with aqueous humor or tissues after implantation. Important parameters to describe the physicochemical surface properties are the contact angle and critical surface tension. Therefore, we performed measurements of the contact angle and critical surface tension of several commercially available IOLs. <i>Setting:</i> Department of Ophthalmology, Johannes Gutenberg University, Mainz, University Eye Hospital, Tübingen, and Max Planck Institute for Polymer Research, Mainz, Germany. <i>Methods:</i> A total of 17 commercially available standard quality IOL types (6…
Motion detection in goldfish investigated with the optomotor response is “color blind”
1996
AbstractThe action spectrum of the optomotor response in goldfish was measured to investigate which of the four cone types involved in color vision contributes to motion detection. In the dark-adapted state, the action spectrum showed a single maximum in the range of 500–520 nm, and resembled the rod spectral sensitivity function. Surprisingly, the action spectrum measured in the light-adapted state also revealed a single maximum only, located in the long wavelength range between 620 and 660 nm. A comparison with spectral sensitivity functions of the four cone types suggests that motion detection is dominated by the L-cone type. Using a two colored, “red-green” cylinder illuminated with two…
100 Years of Benham's Top in Colour Science
1995
For 100 years Benham's top has been a popular device demonstrating pattern-induced flicker colours (PIFCs). Results of early and recent investigations on PIFCs are reported and show that the phenomenon originates in phase-sensitive lateral interactions of modulated neural activity in the retina followed by additional spatial interactions in the visual cortex behind the locus of binocular fusion. Colour matches with normal colour stimuli indicate that S/(M + L) opponent neurons are involved. Dichromats do not find matching stimuli for all PIFCs. PIFCs may become useful in medical diagnosis. The phenomenon is interpreted as a side effect of a neural mechanism providing colour constancy under…
On the growth of maars and diatremes and its relevance to the formation of tuff rings
1986
Small and large maars exist associated with small and large diatremes, respectively, their subsurface feeder structures. The problem of size and growth of maar-diatreme volcanoes is discussed from a phreatomagmatic point of view from field data, some geophysical data, and short-lived historic maar eruptions. A hydrostatic pressure barrier of usually about 20–30 bars is assumed to control the maximum depth level of explosive magma/groundwater interactions. Similar to the situation in submarine and subglacial volcanism, initial maar-forming water vapour explosions are therefore assumed to occur at shallow depth and to produce a small maar with a shallow diatreme. Because of limited availabili…
Maars of the Westeifel, Germany
2008
Within the Westeifel Volcanic Field 27% of the 250 Quaternary eruptive centers are maars. Maars form as a result of a highly explosive interactive process between rising melt and groundwater. In the Westeifel, probably thermal water plays an important role for the productive phreatomagmatic interaction process and, con-sequently, the high number of maars. The Westeifel maars show all transitions to scoria cones. Only the youngest maars are filled by a maar lake or a raised bog, and are well preserved. The older maars show a low diameter to depth ratio. Nearly one third of the Westeifel maars were formed during the Weichselian glaciation period. The isostatic movements during the increasing …
Relationships between diffuse CO 2 emissions and volcanic activity on the island of Vulcano (Aeolian Islands, Italy) during the period 1984-1994
2002
Measurements of CO2 flux from the ground were periodically carried out on the island of Vulcano (Aeolian Islands, Italy) between 1984 and 1994. Three high-flux areas were identified at the foot of the volcanic cone (La Fossa), either inside or very close to the main village. Effect of the choice of the sampling grid was evaluated. A different sampling grid resulted in similar distribution patterns, but with different CO2 fluxes. Therefore, the absolute estimate of the total flux from the investigated area includes a large degree of uncertainty, but repeated measurements with permanent sampling sites are accurate and can detect small changes. No correlation of the flux with atmospheric param…
Estudio volumétrico de la cresta ósea infracigomática mediante tomografía computarizada de haz cónico
2023
Introducción. El estudio anatómico en tres dimensiones de la cresta infracigomática bajo un protocolo de estudio común, previo a la colocación de dispositivos de anclaje temporal, proporciona al clínico una herramienta de pronóstico clave en la seguridad y estabilidad del tratamiento. Objetivos. El propósito de la presente tesis doctoral fue evaluar de forma transversal la cresta ósea infracigomática (IZC) mediante Tomografías Computarizadas de Haz Cónico (TCHC) en primeros y segundos molares superiores, para el estudio sistematizado y enfocado a la colocación de dispositivos de anclaje temporal en ortodoncia. Los objetivos fueron: determinar la altura total de la cresta infracigomática en …
Temes Bioquímica II, Grau de Nutrició Humana i Dietètica, UVEG
2019
Temes de la assignatura de Bioquímica II del Grau de Nutrició Humana i Dietètica. Inclou la gluconeogènesi, metabolisme del glucogen, metabolisme de nucleòtids, integració del metabolisme i especialització dels òrgans i teixits. A mes, inclou un tema de sintesi de proteïnes. Different subjects of Biochemistry II, a basic subject of the Degree in Human Nutrition and Dietetics. It includes gluconeogenesis, glycogen metabolism, nucleotid metabolism, integration of metabolism and tissue and organ specialization. In addition, it includes the subject of protein synthesis.
Evolución de la información integrada en el mundo: análisis de sus primeras etapas de formulación
2017
La Información Integrada (IR), ha sido planteada como la concreción de toda la información de las organizaciones en un único documento, el cual debe ser preparado desde una perspectiva de sostenibilidad, y cuyo objetivo debe orientarse a informar acerca de la creación de valor por parte de las organizaciones (Eccles & Krzus, 2010). El objetivo de la IR es cubrir las crecientes demandas de transparencia e inclusión, por parte de todos los stakeholders de las organizaciones. Bajo el concepto de IR, se propone que los contenidos antes desplegados en distintos informes corporativos, ahora, no sólo se presenten juntos, sino que además sean pensados y producidos de manera integrada (Jensen & Berg…
¿Quién sabe si es posible saber lo que es justo? la teoría del conocimiento y el estatuto epistemológico de las ciencias normativas: a propósito de H…
2011
RESUMEN En esta comunicación se sugiere una revisión de la clásica escisión entre teorías cognotivistas y no cognotivistas, a la luz que pueda resultar del repaso a algunos hitos de la teoría del conocimiento como nueva “filosofía primera” o “filosofía primera” propia de la modernidad y que debieron afectar a la cuestión del estatuto epistemológico de las llamadas ciencias normativas. Se hace especial referencia a la teoría del conocimiento de David Hume. ABSTRACT In this paper we suggest a revision of the classic division between cognotivistic and non cognotivistic points of view after reviewing some “highlights” of the theory of knowledge as a new "first philosophy" or philosophy of mod…