1,363 research outputs found
Review of simulating four classes of window materials for daylighting with non-standard BSDF using the simulation program Radiance
This review describes the currently available simulation models for window
material to calculate daylighting with the program "Radiance". The review is
based on four abstract and general classes of window materials, depending on
their scattering and redirecting properties (bidirectional scatter distribution
function, BSDF). It lists potential and limits of the older models and includes
the most recent additions to the software. All models are demonstrated using an
exemplary indoor scene and two typical sky conditions. It is intended as
clarification for applying window material models in project work or teaching.
The underlying algorithmic problems apply to all lighting simulation programs,
so the scenarios of materials and skies are applicable to other lighting
programs
Effects of the inoculation with arbuscular mycorrhizal (AM) fungus of the genus Glomus on growth and leaf mineral concentrations of grapevine (Vitis vinifera cv. Cabernet Sauvignon)
The effects of root inoculation with mycorrhizal fungi (genus Glomus) on growth and leaf mineral concentrations of grapevine (Vitis vinifera cv. Cabernet Sauvignon) were studied under the growth conditions of Central Chile. Inoculation enhanced the uptake of N and K and vegetative growth but decreased the foliar concentration, but not necessarily the uptake of P
On a necessary aspect for the Riesz basis property for indefinite Sturm-Liouville problems
In 1996, H. Volkmer observed that the inequality
is
satisfied with some positive constant for a certain class of functions
on if the eigenfunctions of the problem form a Riesz basis of the Hilbert space
. Here the weight is assumed to satisfy
a.e. on .
We present two criteria in terms of Weyl-Titchmarsh -functions for the
Volkmer inequality to be valid. Using these results we show that this
inequality is valid if the operator associated with the spectral problem
satisfies the linear resolvent growth condition. In particular, we show that
the Riesz basis property of eigenfunctions is equivalent to the linear
resolvent growth if is odd.Comment: 26 page
Helenas und Fabiennes Welt. Eine Freundschaftsbeziehung im Unterricht
Der Aufsatz analysiert ethnografische Feldnotizen aus einer Unterrichtsstunde, die in einer achten Klasse eines traditionsbewussten Gymnasiums stattgefunden hat. Der Fokus liegt auf den Interaktionen zweier befreundeter Schülerinnen. Die Analyse ihrer \u27mikrokulturellen Welt\u27 innerhalb der Unterrichtssituation orientiert sich an der sequenziellen Ordnung des Materials und verfolgt das Ziel, Freundschaft unter den Bedingungen von Unterricht und Unterricht aus der Perspektive von Freundschaft zu betrachten. Die ethnografische Studie eröffnet mit der Beschreibung gleichzeitiger Handlungsebenen die Möglichkeit, die Anforderungen an die Mädchen - durch Unterricht und Freundschaft - in den Blick zu nehmen und die Verschränkungen zwischen den freundschafts- bzw. unterrichtsbezogenen Aktivitäten der Schülerinnen sichtbar zu machen sowie auf ihre Funktionen zu befragen. (DIPF/Orig.)The article mainly analyzes and interprets ethnographic field notes that were taken in an eighth grade school lesson in what is considered a \u27traditionally oriented\u27 gymnasium. The notes focus on the interaction of two students (girls), who neighbor each other in the classroom. The interpretation of their micro-cultural world during the class lesson is based on the sequential arrangement of the material and attempts to bring into view friendship in the context of school lessons as well as school lessons from the perspective of friendship. By describing simultaneous levels of interaction, the ethnographic studies grant the accessibility of the girls\u27 different requirements for friendship and school. The ethnographic studies also make visible the intertwinement between the class room activities and those relating to friendship as well as their significance. (DIPF/Orig.
Psb31: a novel photosystem II associated protein in Synechocystis sp. PCC 6803
The aim of this thesis is to investigate possible functions of the Psb31 protein in the cyanobacterium Synechocystis sp. PCC 6803. This protein was originally identified by Yasuhiro Kashino et al. (2002) as part of an active photosystem II (PSII) preparation and is present only in prokaryotic and eukaryotic photosynthetic organisms. The Arabidopsis thaliana homologue has been show to be involved in D1 turnover and PSII dimerization. The expression of the psb31 homologue in Cyanothece sp. ATCC 51142 is co-regulated with photosynthetic genes, in particular PSII genes. A deletion of the psb31 gene does not impair photoautothrophic growth, but in competition experiments the mutant is out-competed under high light stress. This phenotype is minor as when grown separately, the growth rates and physical properties of Δpsb31 and WT are similar. It could be shown that the decreased fitness is caused by a higher sensitivity to reactive oxygen species, in particular to singlet oxygen rather than to hydrogen peroxide. Singlet oxygen is generated as byproduct of the PSII reaction and is thought to inhibit D1 protein synthesis by interfering with the elongation step of translation, but I found that photoinhibition and recovery are not affected in the Δpsb31 mutant. However, singlet oxygen is efficiently quenched by carotenoids and I found, that a truncated Psb31 protein expressed in E.coli binds carotenoids. A polyclonal antibody against Psb31 was generated and I could show that the protein is a membrane protein located mainly in thylakoid membrane but also present in the plasma membrane. It is part of highly active PSII preparations, but only in sub-stoichiometric amounts. These findings lead me to the conclusion, that Psb31 is a PSII associated protein whose function might be to bind partially assembled PSII complexes and prevent the release of singlet oxygen into the cellular environment
Discurso de Recepción del Miembro Académico don Pablo Krassa, pronunciado por el ingeniero señor don Jorge Von Bennewits
Conductive nanodots on the surface of irradiated CaF2
CaF2(111) single crystal surfaces have been irradiated with swift heavy ions
under oblique angles resulting in chains of nanosized hillocks. In order to
characterize these nanodots with respect to their conductivity we have applied
non-contact atomic force microscopy using a magnetic tip. Measurements in UHV
as well as under ambient conditions reveal a clearly enhanced electromagnetic
interaction between the magnetic tip and the nanodots. The dissipated energy
per cycle is comparable to the value found for metals, indicating that the
interaction of the ion with the target material leads to the creation of
metallic Ca nanodots on the surface
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