Structural similarity between TAFs and the heterotetrameric core of the histone octamer

A complex of two TFIID TATA box-binding protein-associated factors (TA FIIs) is described at 2.0A resolution. The amino-terminal portions of dTAFII42 and dTAFII62 from Drosophila adopt the canonical histone fold, consisting of two short alpha-helices flanking a long central alpha-helix. Like histones H3 and H4, dTAFII42 and dTAFII62 form an intimate heterodimer by extensive hydrophobic contacts between the paired molecules. In solution and in the crystalline state, the dTAFII42/dTAFII62 complex exists as a heterotetramer, resembling the (H3/H4)2 heterotetrameric core of the histone octamer, suggesting that TFIID contains a histone octamer-like substructure.     

Weedpatch syndrome II: an examination of the wildflower movement in North America

This paper describes the origin, strengths and shortcomings of the wildflower movement in North America. At present, the wildflower industry needs to improve the longevity of seed mixes and provide mixes that are more applicable to a wider variety of site conditions and regions. In addition, some alien wildflowers should not be introduced to the North American landscape; in contrast, the potential of some native species regarded s weeds is being overlooked. The present situation in North America for the implementation and a management of landscapes with wildflowers can be described as an integrated design approach.     

Non-linear characteristics of engineering soils

The paper deals with the non-linear stress-strain characteristics of engineering soils and investigates some of the more important factors relating to the elasto-plastic behaviour. A review of previous literature describes some of the work already performed in this area of study, and discusses the applicability of the theories proposed, most of which have been established using results obtained from a standard tri-axial test. A non-linear stress-strain theory is formulated, using results from a true tri-axial test, which also takes into account the behaviour of the soil during unloading and subsequent reloading. This behaviour is shown to depend on the stress levels attained in the unloading/reloading hysteresis loop in which the reloading portion of the loop is closely linearly elastic. Finally, the suitability of the proposed equations in typical engineering calculations is discussed and a worked example is included which demonstrates how the proposed incremental stress-strain equations may be applied in analysis.

List of symbols

The notation used in the theoretical work is as follows: E modulus of elasticity of soil - H vertical depth of cavity - K ₀ coefficient of earth pressure at rest assumed constant with depth - K _r Rankine ratio=(1 – sin )/(1 + sin ) - K, K ₁,K ₂,f ₁,f ₂,g, m, n constants found experimentally - k R ₀ ²/R₁ ² - p _h stress in any horizontal direction whenp _x =P _z =P _h - p _r radial stress - p _x stress inx-direction - p _y vertical stress - p _z stress in z-direction - p _xi ,p _yi ,p _zi stress levels in co-ordinate directions at commencement of unloading/reloading cycle - p _xf ,p _yf ,p _zf stress levels in co-ordinate directions at end of unloading portion of unloading/reloading cycle - p circumferential stress - p _u ultimate pressure in cavity - R ₀ initial radius of cavity - R ₁ ultimate radius of cavity - R ₂ radius of plastic zone - r a radial distance from centre of cavity to typical element in elastic or plastic zone - r ₁,r ₂,r ₃ stress ratiosp _x (ultimate)/p _xi ,p _y (ultimate)/p _yi ,p _z (ultimate)/p _zi respectively - t step length - w radial displacement of elastic zone - soil density - average volumetric strain of plastic zone - _r volumetric strain of increment of plastic zone - _pr , _r , etc. a small increment of the quantity concerned - _r radial strain - _x strain inx-direction - _y vertical strain - _z strain inz-direction - circumferential strain - _xyi etc strain in thex-direction due to loading in-direction at commencement of unloading/reloading cycle, etc. - _xyf , etc strain in thex-direction due to loading in-direction at end of unloading portion of unloading/ reloading cycle, etc. - Poisson's ratio - angle of internal friction of soil     

[60]Fullerene Amino Acids and Related Derivatives

Abstract

This paper is a review of the literature concerning the preparation of [60]fullerene amino acid and peptide derivatives. The structure and applications of these derivatives to the biological and Material sciences is also presented.     

Ptex: Per‐Face Texture Mapping for Production Rendering

Explicit parameterization of subdivision surfaces for texture mapping adds significant cost and complexity to film production. Most parameterization methods currently in use require setup effort, and none are completely general. We propose a new texture mapping method for Catmull‐Clark subdivision surfaces that requires no explicit parameterization. Our method, Ptex, stores a separate texture per quad face of the subdivision control mesh, along with a novel per‐face adjacency map, in a single texture file per surface. Ptex uses the adjacency data to perform seamless anisotropic filtering of multi‐resolution textures across surfaces of arbitrary topology. Just as importantly, Ptex requires no manual setup and scales to models of arbitrary mesh complexity and texture detail. Ptex has been successfully used to texture all of the models in an animated theatrical short and is currently being applied to an entire animated feature. Ptex has eliminated UV assignment from our studio and significantly increased the efficiency of our pipeline.     

Variable effects on egg yolks and yolk lipoprotein fractions of feeding methyl sterculate to hens: Periodic changes in lipid composition and gelation temperature

As part of a study of the reasons for the large effects of a small dietary supplement of methyl sterculate on the physical properties and lipid composition of hen's egg yolk, individual yolks from sterculate-fed hens have been examined. These yolks set to a firm gel on cooling in the range 20-0 °C, but there were large variations in eggs from different hens that were accompanied by variations in the proportion of saturated fatty acid residues in the yolk lipids. Gel formation was reversible on immediate rewarming but prolonged storage at low temperature caused irreversible alterations. Diluted yolk showed analogous changes in viscosity on cooling and provided a convenient model system for examining the effect of pH, ionic strength, and the action of trypsin. From these results it is concluded that the protein of the high-lipid low-density lipoprotein of yolk is directly involved in the gelation of the yolk. A series of eggs laid by one sterculatefed hen over 30 days showed large and possibly periodic variations in the lipid composition and gelation temperature of the yolks. These results and some data from other hens suggested that large variations in yolk properties accompany a high response to sterculate feeding.     

Modelling dispersive optical fibres with a circuit simulator

The authors describe a new approach to modelling the optical electric field envelope function using a standard circuit simulator, show application to the calculation of dispersive linear propagation in a uniform single-mode optical fibre, and demonstrate that such a model can be integrated with an existing model of a semiconductor laser