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The absorption coefficient of composite systems, formed by by compacting together small metal particles and finely ground KCl powder, has been measured at far infrared frequencies (4−400 cm−1). The measurements were made on particles of aluminum, prepared by inert gas evaporation, having mean diameters in the range 200 A to 1000 A and on particles of palladium, with mean diameter 2 μm. Measurements were made for metal filling factors, f, between 0.001 and 0.10. The absorption coefficient is nearly linear in concentration for small concentrations but rises more rapidly than linearly at larger values of f, indicating the onset of a metal‐insulator transition. The dependence of the absorption coefficient on particle size is very weak. A theory which includes eddy current (magnetic dipole) absorption gives a fair description of the data for the largest particles but falls several orders of magnitude below the data for the smallest ones.

Non-bolometric detection is observed in granular superconducting NbN films. Detection, related to the non-linear I-V's, occures over a large bias range. Preliminary results give a sensitivity of 20 V/W and NEP of 5×10−6W at 4 K. Granular NbN films show no apparent degradation with time.

The effects of alloy composition and of process variables such as roll material and velocity, ribbon thickness, annealing temperature and pressing conditions on the microstructure and magnetic properties of chill-block melt spun FeNdB-based ribbons and of magnets derived by hot-pressing the ribbons have been studied. Measurements by X-ray diffraction line broadening analysis indicate that a very small grain size (typically 30-80nm) plays a major role in promoting high coercivity iHc and energy product (BH)Max but they also suggest that other, less identifiable, factors also play a role. Substitution of Fe by Co leads to generally improved properties at elevated temperatures for hot pressed magnets as well as for the as-spun ribbon. Small additions of niobium and of silicon can lead to substantial improvements in coercivity and to remanence respectively, although the effect of the silicon appears to be particularly sensitive to the melt spinning parameters. The morphology of the microcrystallites is also, correspondingly, changed markedly by the silicon additions but the role of this in the enhancement of energy product requires further clarification.

Measurements of the 34S/32S ratios in sulphides from the slightly metamorphosed Lady Loretta deposit show the sphalerite and galena to be in isotopic equilibrium. Pyrite in immediate association with these sulphides is not isotopically related. A similar distribution of sulphur isotopes had previously been noted in the even less altered McArthur deposit, for which a dual sulphur source was postulated. This fresh isotopic evidence from Lady Loretta now suggests that such a genesis for stratiform sulphides from the Proterozoic is not uncommon.

Infrared spectroscopy of conventional superconductors shows Drude electronic behavior above T c , gap behavior below T c , and almost no phonons because of screening. In contrast, our spectra (50–600 cm−1) of the rare earth barium copper oxides R x B a 3–x C u 3 O 7 (R =Y, Gd, Tm; x= 1, 1.5) show few carriers and strong phonon modes. The spectra yield 2Δ/kT c ≥ 3.6 and suggest enhanced plasmon-phonon interaction near the gap which may be important for high-T c superconductivity (1–4).

A simple method of treating these teeth is described. The authors describe the use of orthodontic brackets, .017 twist wire, and compressed open coil springs. Correction is accomplished in six to eight weeks with minimal adjustments required.

Measurements of far infrared transmission and reflection have been done on composites consisting of small tin particles (approximately 250A radius) embedded randomly in an insulating matrix of KCl, with volume fraction of tin ranging from 0.001 to 0.03. These experiments measure the optical properties from 3 cm−1 to 50 cm−1 and at temperatures from 1.7K to 27K, thus covering the energy gap frequency and the transition temperature of the tin. The results of these experiments show an enhanced absorption around the gap frequency at superconducting temperatures.

Over a six-year period, 200 patients requiring long-term oxygen therapy for hypoxemic lung disease underwent insertion of the micro-trach transtracheal catheter and were evaluated for one to seven years. The catheter requires no removal for cleaning; it is designed to function undisturbed within the trachea for six months between replacements. Transtracheal oxygen delivery and saline instillation were instituted immediately after inserting the device. Oxygen administration at a rate of 0.25 to 3 L/min was equivalent to 1 to 8 L/min delivered nasally. By the end of one year of follow-up, 12.5 percent of patients had dropped out of the study. Most patients comply with prescribed 24-hour-a-day oxygen use; in keeping with the NOTT study, life expectancy of emphysema patients may therefore be increased.

Since its onset, the acquired immunodeficiency syndrome (AIDS) epidemic has been associated with certain subgroups in the U.S. population. These include gay and bisexual men, intravenous drug users, hemophiliacs and blood product transfusion recipients. Members of these groups feeling either well or unwell may present themselves at clinics with a high level of anxiety regarding AIDS. Their needs for clinical evaluation of symptoms, education and reassurance, or further referral may be acute. The experience of the AIDS screening clinic at the AIDS/oncology clinic at San Francisco General Hospital has led to the development of protocols for nurse practitioners to use in screening members of AIDS risk groups, both the "worried well" and those who are symptomatic. This is a presentation of the clinic's screening history and physical examination criteria, including the markers of suspicion and algorithms of diagnostic studies that have been useful tools in the clinic.

Performance and stability advantages were determined for the addition of wings to a ground effect machine. The work is both theoretical and experimental, the later being accomplished both with models and a winged version of the full scale Curtiss-Wright Air Car. Results indicate that substantial gains in both performance and stability are attainable by such a hybrid machine when compared to the pure GEM. For the high speed cruise condition, wings will be found most beneficial if the base loading of the craft is not excessive.

To address the growing needs of the NSLS user community we are aggressively pursuing R&D towards a facility upgrade. The present goals are a 3 GeV ultra-low emittance storage ring, tailored to the 5-20 keV photon energy range, that will triple the present NSLS ID capacity, and provide three orders of magnitude increase in brightness over the present brightest NSLS beamlines. To achieve these goals we propose a 24 period TBA lattice, with extensive use of super-conducting small gap undulators. This paper reviews our preliminary design and the key accelerator physics issues.

The introduction of microscopes in clinical and surgical endodontics is fairly recent. Potential applications, including removal of fractured instruments, localizing calcified canals, soft tissue management and root-end procedures, are reviewed.

Detection of submillimeter radiation between 10 and 40 cm−1 (300–1200 GHz) has been carried out with a high resistance granular NbN film (R⧠= 8440 Ω/⧠) below 6 K with evidence of Josephson‐like operation. The nonoptimized detector sensitivity and noise equivalent power at 17.5 cm−1 (525 GHz) were about 20 V/W and 5×10−8 W/Hz1/2, respectively, comparable to values obtained with granular Sn and Pb.

In lignotuberous species of the Lehmannianae, lignotuber formation is preceded by the appearance of a crescent-shaped array of accessory buds, adaxial to the axillary bud. Lignotubers may be formed at successive nodes but those with only one upper accessory bud (which may be present even in non- lignotuberous species) do not form lignotubers. The subsequent development of the lignotuber is described, as is the development of the seedling. Seedling shoot growth is characterized by indeterminate growth and, like that of the adult shoots, is sympodial. In well protected sites lignotuberous species may develop into small, single-stemmed trees but in harsher habitats death of the seedling shoot and its replacement from lignotuber buds result in enlargement of the lignotuber and enhance the tendency to adopt a mallee (many-stemmed) form. Non-lignotuberous and lignotuberous species of the Lehmannianae occur side-by-side in habitats that are prone to fire. Lignotuberous species survive shoot-destructive vicissitudes, such as fire, by replacement from the lignotuber. Whereas flowering and fruiting of seedlings of lignotuberous species may be postponed for many years, seed production is precocious in the non-lignotuberous species of the series. This is regarded as an alternative adaptation to fire, which is one of the major factors of the habitats of the Lehmannianae. Even-aged pole stands of the non-lignotuberous species result from regeneration from seed, after fire. Following the production of gaps in the canopy and the thinning out of the stand, pole-stage trees assume their mature form by outgrowth of epicormic shoots, including some placed near the base of the trunk.

A correlation is described between the sizes of the stomata (length, pole to pole) and diameter of the largest oil glands of two closely related species, previously thought conspecific, of a newly described group (series Lehmannianae) of eucalypts. The oil glands and stomata of E. lehmannii are larger than those of E. conferruminata. The correlation is independent of leaf size and shape. The size correlation has its roots in the fact that both stomata and the largest oil glands have their origin in single epidermal initials.

An initial survey of the diversity of early lignotuber development in Eucalyptus and an analytical study of the anatomy of young lignotubers and the seedling stem are presented. Studies of the early stages of the morphological development of the lignotuber in 13 species, representative of five taxonomic groups, resulted in the recognition of four modes of lignotuber initiation. The importance to lignotuber formation of the presence of a suite of accessory buds, adaxial to the axillary bud, is emphasized but lignotuber initiation is not in all cases associated with these buds. Lignotuber buds are derived by branching from existing buds, ultimately from the accessory buds of the node. Following its initiation, the possibilities of later morphological development of the lignotuber are discussed. Lignotuber growth may dominate over stem growth and the lignotubers at a node may then fuse laterally to encircle the stem. Stem growth, on the other hand, may dominate over lignotuber growth and the lignotuber then appears to regress. The consequences for the growth habit of the plant of these alternative pathways of development are outlined. The wood of young lignotubers (and that of the swollen hypocotyl) is shown to be different in composition and in the sizes of its elements from that of seedling stem wood; these differences owe their origin to differences in the nature and performance of the cambia of the lignotuber and stem. In lateral fusion of the lignotubers at a node, and their upward and downwards extension over the stem, e.g. over the hypocotyl, stem cambial initials are either progressively lost or, more likely, converted to lignotuber-type initials. The possibility of the reverse process occumng in stem dominance is discussed.

Experiments involving surgery such as ring-barking or excision of lignotubers of seedling Eucalyptus st johnii plants are described. Removal of the strip of stem bark and cambium from between two lignotubers at the same node delays but does not prevent their lateral fusion. Ring-barking results in outgrowth of lignotuber buds below the ring and a check in growth, as compared with the untreated lignotuber at the same node. Excision of one lignotuber results in the formation of a 'replacement lignotuber' which lacks lignotuber buds; excision of both lignotubers at a node results in the formation of a pair of replacement lignotubers. Anatomical investigation shows that replacement lignotubers arise following conversion of stem cambial initials to lignotuber-type initials. The results lead to the following conclusions: outgrowth of lignotuber buds is suppressed by the seedling shoot; lignotuber buds do not form adventitiously. At a lignotuberous node, removal of stem or lignotuber cambium results in its replacement from the flanks of remaining lignotuber cambium. Stem cambium is not converted to lignotuber-type cambium by homeogenetic induction since it takes place also in the absence of lignotuber cambium.

Two types of venation in leaves of eucalypts and other members of Myrtaceae are described and their ontogeny investigated in species of Eucalyptus. Primary seedling leaves of eucalypts have brochidodromous venation. A paramarginal vein is formed from the extensions of primary lateral veins and completed by the strengthening of commissural minor veins. Adult Eucalyptus leaves have intramarginal veins that are formed independently of the primary laterals which join them after their formation. The apparently brochidodromous venation of leaves of some species arises as a result of differential growth following the inception of intramarginal veins. Leaves with intramarginal veins are ontogenetically acrodromous. These conclusions are discussed in relation to the system of classification of venation put forward by L. J. Hickey. In particular, problems of ordination, affecting the terminology of veins, and of homology arising from the application of the rules of that system to the Myrtaceae, are dealt with.