Beautiful Shapes Research Articles

Edible and Poisonous Mushrooms of the World

Mushrooms are among the most intriguing and striking inhabitants of the natural world, as highly regarded for their distinctive flavors and uses in cooking and medicine as for their sometimes strange, often beautiful shapes and forms. Some are medicinal, others poisonous or even lethal. "Edible and Poisonous Mushrooms of the World" is a well-rounded look at mushrooms, including their cultivation, ethnobotanical uses, and the fascinating roles they play in nature. The authors provide expert advice on how to identify and distinguish between edible and poisonous wild mushrooms and how to record important details, with suggestions for taking photographs and preparing spore prints. More than 250 stunning photographs accompany the text. Truly international in its coverage, this engaging introduction to the world of mushrooms will appeal to naturalists, students, photographers, chefs, hikers, and potential growers from around the world.

INCOMPATIBLE BEHAVIOR OF SULFUR IN ULTRA-DEPLETED MORB

The assumed presence of a sulfide phase in the residuum after melting of typical MORB is critical for an estimation of sulfur concentrations in the Earth’s mantle and for balancing the abundances of platinum-group elements (PGE) in MORB. Also, this assumption is consistent with the fact that most MORB glasses are close to sulfur saturation (e.g. Jambon, 1994). However, almost all MORB glasses do not represent primary melts because of (1) extensive mixing on the way to the surface (Sobolev and Shimizu, 1993) and (2) significant fractional crystallization. It was shown (Sobolev and Shimizu, 1993; Sobolev, 1996) that ultra-depleted melts trapped as inclusions in high-magnesium olivine are better representatives of the compositions of instantaneous primary MORB melts. Here we present data on the composition of such melts from typical NMORB at 8° N, Mid-Atlantic Ridge, and at the Siqueiros F.Z., East Pacific Rise (Perfit et al., 1996). The inclusions possess beautiful negative crystalline shapes of host olivine and consist of fresh glass with rare shrinkage bubbles. Major element and sulfur concentrations were measured on a Jeol Superprobe electron microprobe at Mainz University (Germany). Long counting times for sulfur peak and background lead to a precision of about 100 ppm with a detection limit of 60 ppm. Trace elements were measured by ims-4f ion probe in the Institute of Microelectronics, Russian Academy of Science (Yaroslavl, Russia) with relative accuracies better than 10%. All inclusions show moderate to minor crystallization of olivine on the cavity walls. This effect was corrected using the procedure of Sobolev and Shimizu (1993). As is apparent from Fig. 1, the sulfur contents show strong positive correlations with highly incompatible elements, and they vary from 0 to 0.10 wt% (the latter is close to saturation level for low-Fe basaltic melts). This fact strongly suggests that sulfide melt was not present in the mantle sources of the ultra-depleted melts at the time of their separation and was probably consumed at lower degrees of melting. The modeling of critical melting of a MORB source suggests that S-undersaturated, ultra-depleted melts were produced at degrees of melting higher than 12% and up to 18% (Sobolev, 1996). This implies that the sulfide might be exhausted from the MORB mantle at degrees of melting higher than 10%, and typical NMORB primary melts were likely segregated from a sulfide-free restite. This result is not in contradiction with high S contents and near sulfur-saturated behavior of MORB because the degree of undersaturation of integral primary melts is relatively small and could be easily compensated by crystallization of 10- 30% phenocrysts. The potential importance of these observations is that they might eliminate one of the otherwise more plausible explanations for the extremely low abundances of platinumgroup elements (PGE) such as osmium and iridium in MORB, namely that these elements are held back in the mantle by residual sulfides, which have very high partition coefficients for PGE.

Symmetry and polyhedral stellation—II

In this article polyhedral symmetry provides the basis for an investigation of the stellation pattern of the deltoidal hexecontahedron, also known as the trapezoidal hexecontahedron, the dual of the rhombicosidodecahedron. This pattern reveals a bilateral symmetry which is indeed rich in the variety of its complexity. It belongs to the icosahedral symmetry group, and as such we expect to find in it a wealth of beautiful shapes. We begin our investigation with a notation identifying the lines of the pattern and the related line segments. The plane cells, also called elementary regions, are then identified. With this information we turn to an analysis of the connectivity of both plane cells and cells in three dimensions. Finally we show how stellated forms can thus be derived.

Sculpting horizons in organic chemistry.

Organic chemistry as a discipline derives from and impacts on the biological and abiological world in which we live. Its challenges lie in the areas of structure, reactivity, techniques, and concepts. Powerful structural tools reveal structures from biology that range from control of insect development and behavior to whole new metabolic pathways in humans. Unnatural products create beautiful new molecular shapes whose properties cannot be predicted as well as catalysts that function with enzyme-like control. From structure flows reactivity. Exploration of known reactions points to new directions, and development of new reactions offers the opportunity of streamlined synthetic design. Emerging new techniques offer new dimensions for performing and studying reactions as well as the hope for developing new ones. Merging disparate facts into unified concepts increases predictive capabilities. The extraordinary difficulty of finding the resultant of many small effects may obscure the presence of general theories, creates the art in the practice of the science, and challenges the practitioner. From these general themes derives the quest for selectivity--chemo-, regio-, diastereo-, and enantio-. An examination of the fundamental underpinnings of the applications of organic chemistry reveals that, while impressive strides have been made, the science is best described as being between infancy and childhood. The cross-fertilization between organic chemistry and molecular biology vividly illustrates a merging of chemistry and biology.

The Formation of Large Drops of Liquid

THE following experiment, based on the temperature-density relations between aniline and water, serves to illustrate to an audience the various shapes through which a drop passes in the course of its formation. A glass beaker, about 9 inches in height and 41/2 inches diameter, is filled to about 7 inches with distilled water, and about 80 c.c. of aniline are added. The beaker is then placed on a burner, and the temperature raised until the aniline floats to the surface of the water. On spreading out at the surface the aniline is cooled, thereby becoming denser than the water beneath. A large drop, 1 inch or more in diameter, then detaches itself from the mass at the surface, the formation being so slow that the altering shapes of the drop, the drawing out of the neck of liquid, and the thinning of the neck in two places may easily be observed. The large, detached drop falls to the bottom of the beaker, and is there re-heated, thereby again becoming lighter than the water, and rising to the surface, when a second drop is formed. By maintaining the temperature about 80° the formation of drops continues indefinitely in the manner described. The slightly pink colour assumed by the aniline enables the experiment to be seen clearly from a considerable distance, and the many beautiful shapes assumed by the drops lend an added interest to this simple method of demonstrating their formation.