Impulse Noise and Neurosensory Hearing Loss—Relationship to Small Arms Fire

The problems of noise are not limited to the simple annoyance of an individual. Noise can produce a permanent hearing handicap. Many everyday activities and hobbies are associated with hazardous exposure to noise. The hunter and the sport shooter are potential subjects of severe and unresolvable hearing loss.Noise-induced hearing loss develops insidiously. The means of prevention are far more simple than is correction of the loss. Wearing ear protectors, plugs or earmuffs, is advisable during exposure to hazardous noise.     

Competition and macroevolution: the ghost of competition yet to come?

Competition theory is the focus of much debate among both neontologists and palaeontologists. This paper explores the expansion of competition theory into macroevolution, since this is the relevant context for palaeobiologists, and challenges the contention that microevolutionary processes are generally inappropriate to the interpretation of macroevolutionary pattern. We show that the term 'interspecific competition' is imprecise, since it conflates processes operating at various hierarchical levels, and recommend a terminological change in accordance with hierarchy theory. Finally, we reassess the role of competition and its absence in radiations. Since evolutionary novelties must be fixed at speciation, and speciation occurs in response to habitat destruction rather than the freeing of ecological space, we believe the role of competition to be minimal in both radiation and the generation of novelty.     

Relationship between δ13C and photosynthetic parameters and their responses to leaf nitrogen content in six broadleaf tree species

Stable carbon isotope composition (δ¹³C), net photosynthetic rate (P _N), actual quantum yield of photosystem 2 (PS2) electron transport (ΦPS2), nitrogen content (N_c), and photosynthetic nitrogen use efficiency (PNUE) in the leaves of six broadleaf tree species were determined under field environmental conditions. The six tree species were Magnolia liliflora Desr., M. grandiflora Linn., M. denudata Desr., Prunus mume (Sieb.) Sieb. et Zucc. cv. Meiren Men, P. mume (Sieb.) Sieb. et Zucc. f. alphandii (Carr.) Rehd., and P. persica (L.) Batsch. var. rubro-plena. The relationships among δ¹³C, Φ_PS2, P _N, and PNUE, as well as their responses to N_c in the six species were also studied. Both P _N and δ¹³C negatively correlated with N_c, but Φ_PS2 positively correlated with N_c. This indicated that with N_c increase, P _N and δ¹³C decreased, while Φ_PS2 increased. There were weak negative correlations between δ¹³C and PNUE, and strong negative correlations (p<0.01) between Φ_PS2 and PNUE. According to the variance analysis of parameters, there existed significant interspecific differences (p<0.001) of δ¹³C, P _N, Φ_PS2, PNUE, and N_c among the tree seedlings of the six tree species, which suggests that the potential photosynthetic capacities depend on plant species, irradiance, and water use capacity under field conditions.     

Molecular aggregation of nucleotides and carbohydrates—their implication to prebiotic polymerization

Hydrogen bonding pattern of nucleotides and carbohydrates has been analysed using Cambridge database. An analysis on ribonucleotides shows the 3′ …5′ hydrogen bond mediated aggregation to be the most common alignment. The 2′ …5′ alignment, which occurs under special circumstances in nature, is found to be the second choice. An analysis on carbohydrates suggests that self assembly of these molecules is not conducive to the formation of polysaccharides of the type which are found in present day living organisms. Further, the role of water molecules in the polymerization of three important biomolecules, namely nucleotides, carbohydrates and amino acids, has been analysed. Implication of these results to prebiotic polymerization is discussed DCB contribution No. 804.     

Culture collections — their services to biotechnology

The need to recruit qualified and experienced employees is a major concern of many organizations engaged in biotechnology. Universities and industry are scoured to find the right people, but where are we to find promising new candidates for the most numerous, and arguably most talented section of the biotechnological workforce — microorganisms and other types of cells? The international network of culture collections offers the best answer, and a proper understanding of their roles and capabilities can save biotechnologists an immense amount of time and money.Among the millions of microbial, plant and animal cells stored in the world's culture collections it is often possible to find one that exactly suits a biotechnologist's particular requirements or one that can be developed to perform a specific task. This article outlines the services offered by culture collections, generally using the UK collections as examples of the main activities throughout the world.     

Veneers and plywood—their manufacture and use

Two closely related industries that depend, to a major degree, upon domestic sources of red gum, Douglasfir, black walnut, red and white oaks, sugar maple, Sitka spruce, Ponderosa pine and Port Orford cedar; and upon foreign sources of mahogany, rosewood, zebrawood, avodiré, bossé, ebony and other exotic species.     

Entropy and symmetry — their relation to thought processes in the biological system

This paper addresses the topic of the electrophysiology of thought processes in a biological system. A classification and criticism of definitions of intelligence is presented. The engenderment of intelligent regulations of behavior is seen to involve stipulations concerning the relation of metron to logon informational content (MacKay, 1950). The relationship is of a nature similar to that hidden behind the Maxwell demon (Maxwell, 1871), and to certain difficulties already faced in quantum mechanics. As thought structures observe conservation of variety under transformations, the conservation of entropy in thermodynamics is investigated. Conservation occurs in a Carnot cycle (Carnot, 1824) and only under a Lorenz transformation subject to a symmetry group formation. The symmetry group is topic neutral and could be applied to informational structures. The need for the informational equivalents of a Carnot cycle and Lorenz transformations is described. To depict the interaction of energy and structure, equivalents of Einstein's field equations are needed. The study of symmetry groups by electrophysiological methods is seen to be at least feasible.