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 $(\int_{-1}^1\frac{1}{|r|}|f'|dx)^2 \le K^2 \int_{-1}^1|f|^2dx\int_{-1}^1\Big|\Big(\frac{1}{r}f'\Big)'\Big|^2dx$ is satisfied with some positive constant $K>0$ for a certain class of functions $f$ on $[-1,1]$ if the eigenfunctions of the problem $-y"=\lambda\, r(x)y,\quad y(-1)=y(1)=0$ form a Riesz basis of the Hilbert space $L^2_{|r|}(-1,1)$. Here the weight $r\in L^1(-1,1)$ is assumed to satisfy $xr(x)>0$ a.e. on $[-1,1]$. We present two criteria in terms of Weyl-Titchmarsh $m$-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 $r$ 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 SchÃ¼lerinnen. 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 erÃ¶ffnet mit der Beschreibung gleichzeitiger Handlungsebenen die MÃ¶glichkeit, die Anforderungen an die MÃ¤dchen - durch Unterricht und Freundschaft - in den Blick zu nehmen und die VerschrÃ¤nkungen zwischen den freundschafts- bzw. unterrichtsbezogenen AktivitÃ¤ten der SchÃ¼lerinnen 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 Î”psb31 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 Î”psb31 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

### 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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