Electron beam evaporation of superconductor-ferromagnet heterostructures.

We report on the electronic and magnetic properties of superconductor-ferromagnet heterostructures fabricated by electron beam evaporation on to unheated thermally oxidised Si substrates. Polycrystalline Nb thin films (5 to 50 nm thick) were shown to possess reliably high superconducting critical temperatures ([Formula: see text]), which correlate well with the residual resistivity ratio (RRR) of the film. These properties improved during ex-situ annealing, resulting in [Formula: see text] and [Formula: see text]RRR increases of up 2.2 K ([Formula: see text] 40% of the pre-annealed [Formula: see text]) and 0.8 ([Formula: see text] 60% of the pre-annealed RRR) respectively. Nb/Pt/Co/Pt heterostructures showed substantial perpendicular anisotropy in the ultrathin limit (≤ 2.5 nm), even in the extreme limit of Pt(0.8 nm)/Co(1 nm)/Pt(0.6 nm). These results point to the use of electron beam evaporation as route to line-of-sight deposited, low-thickness, high quality Nb-based superspintronic multilayers.

Soil-based treatment of partially treated liquid swine manure.

A soil-column system was tested for the removal of soluble organics and nutrients from partially treated liquid swine manure. The liquid manure was applied to the 900 mm deep (300 mm of local topsoil and 600 mm of local subsoil) soil columns continuously for an eight-week period, and leachate as well as soil samples were analysed. An effective liquid manure application rate of 17 mm d(-1) was determined based on a preliminary liquid manure soil-based treatment experiment. It was found that more than 90% of five-day biochemical oxygen demand, chemical oxygen demand, total Kjeldahl and ammonia nitrogen, and total phosphorus could be effectively removed from the liquid manure by the soil system. Nitrogen contents accumulated in the soil matrix mostly within the 0 to 300 mm depth, while no significant increase was observed in sub soils. Soil analyses indicated the occurrence of nitrification and denitrification in the soil columns. Nitrogen balance showed that about 42% of the applied nitrogen was lost from the system during the liquid manure soil-based treatment experiment, suggesting the emission of ammonia and other gaseous nitrogen generated through nitrification and denitrification. The leachate of the soil treatment system was used to irrigate Bermuda grass. No negative effect of leachate was observed on the plant growth.

UV inactivation of bacteria in raw and pretreated liquid swine manure.

The study was conducted to investigate the effectiveness of ultraviolet (UV) irradiation for inactivating coliform bacterial indicators in liquid swine manure samples using a laboratory-scale, low-pressure UV collimated beam apparatus. Raw liquid swine manure was brought from the field and stored at 4 'C for preliminary settling for 24 hours, which was followed by alum treatment in a jar test apparatus. Both pre-settled and alum-treated supernatants were filtered separately through different pore-sized polycarbonate membrane filters. The unfiltered and filtered pre-settled and alum-treated supernatant samples were exposed to a range of UV fluences (i.e., doses) to determine the fluence-response relationship. After preliminary settling, alum treatment, and membrane filtration, UV absorbance values of undiluted swine manure samples at 254 nm varied between 4.0 and 4.2 cm(-1) with total suspended solids concentrations of 800 to 1,800 mg l(-1). Total coliforms were reduced by 2 - to 2.5-log10 at UV fluences of 80 to 100 mJ cm(-2). Relatively small log reductions (< 0.5-log10) were observed at lower fluences (below 20 mJ cm(-2) ) in undiluted manure samples. To reduce the UV absorbance of liquid swine manure, raw manure was diluted 1:50 and 1:10 with deionized water in subsequent experiments. Almost complete inactivation (> 4 to 5 log10) was achieved at UV fluences of 20 mJ cm(-2) or higher in the swine manure samples diluted to 1:50. Based on these findings, it was proposed that UV inactivation of coliform in the undiluted liquid swine manure was limited by association of bacterial cells with particulate matter of less than 10 microm in size. Dilution may have disrupted and reduced the association between the bacteria and this fine particulate matter resulting in better dispersion and more complete inactivation by UV.

Physical and chemical processes for removing suspended solids and phosphorus from liquid swine manure.

A physical/chemical treatment train, that included 24-hour preliminary settling followed by coagulation/flocculation and sedimentation, was tested at a laboratory bench scale to treat liquid swine manure for the removal of total suspended solids (TSS) and total phosphorus (TP). Preliminary (i.e., natural) settling time had an effect on TSS removal within only the first 24 hours. TSS removal efficiency reached 75% (TSS concentration was reduced from 5,800 to 1,450 mg 1(-1)) after 24 hours of preliminary settling. Also, as a result of the 24-hour preliminary settling, TP concentration was reduced from 533 to 318 mg 1(-1), thus leading to a TP removal efficiency of 40%. When compared to ferric chloride, alum was more effective in reducing both TSS and TP. At a 95% confidence interval, alum dose, coagulation Gt (coagulation velocity gradient * rapid-mixing time), and flocculation Gt (flocculation velocity gradient * slow-mixing time) were not significant for TSS removal while alum dose was the only significant factor for TP removal. For the 24-hour settled liquid manure that had a TP concentration in the range of 362 to 401 mg l(-1)and as alum dose increased up to 1,600 mg 1(-1), TP removal efficiency increased up to 70%. Then, the rate of increase in TP removal efficiency per increase in alum dose started to decrease and TP removal efficiency reached about 93% at an alum dose of 3,000 mg 1(-1). Sequential alum dosing improved the TSS removal efficiency while it had no effect on TP removal efficiency. The mass ratio of removed TSS/applied alum increased from about 0.38, during a one-step dosing of alum at a concentration of 1,600 mg l(-1), to about 0.58 during a two-step dosing of alum at a concentration of 1,600 mg l(-1) (i.e., 800 mg l(-1) followed by another 800 mg l(-1)).

Experience journals: using computers to share personal stories about illness and medical intervention.

Medical advances make it increasingly possible for children with previously fatal illness to live and thrive. However, a significant number still experience repeated operations, hospitalization, and invasive procedures, or need special care at home. Many do so with little or no intervention to help them and their families cope with the emotional stresses involved. One significant source of emotional and cognitive support is the community of patients and families who have experienced similar medical procedures. However, in spite of a general willingness to share experiences, communication among patients and families is usually limited. To facilitate this process, we are investigating the use of computer technology to record, organize, and display stories about the experiences of families with children who have been treated for cardiac and neurological illness at Children's Hospital, Boston. We are asking children and their families to record text and multimedia vignettes describing some aspect of their illness, coping strategies, or care that might be useful to others. These contributions will be available for browsing at a secure World-Wide-Web site. However, economic realities preclude reliance on a professional site administrator to organize and monitor what we hope to be a rapidly growing Web site with a large, distributed authorship. The need to make the Web site fully accessible to users who have varying familiarity with computers and Web browsing imposes further constraints. We are therefore developing software to automate the process of managing and organizing an easily accessed Web site that contains an "Experience Journal." We describe this software, the rationale for its development, and our plans for its use in the coming year.

Aspects of written language production over adult life.

Self-descriptions written by adults were analyzed to explore the effects of age, gender, vocabulary, nonverbal intelligence, and educational-occupational status on lexical aspects of language and grammatical complexity. Multivariate analyses indicated that, after controlling for other background variables, age had a significant effect on vocabulary diversity, sentence complexity, subordinating conjunctions, and possibly sentence length. Four variables--word output, word length, long words, and readability--were affected mainly by vocabulary and educational-occupational status. An unexpected and small but significant gender difference in the readability of the descriptions was observed across all age groups.

The idea of ageing: an historical and psychological analysis.

The idea of ageing can be traced back to the earliest written records. Prescientific beliefs were governed by animistic forms of thought leading to attempts to control ageing, disease and death through magic and supernatural agencies. The idea of ageing was gradually elaborated in Greek and Roman medicine and incorporated into religious beliefs and social practices. Ideas from the classical period were revived during the Renaissance, but modern scientific approaches to ageing did not emerge clearly until the 17th century, with systematic medical and statistical inquiries into the causes of death, and later, in the 19th and 20th centuries, into the biological mechanisms of ageing. The idea of an 'elixir of life' has been all but totally abandoned, although increases in the average length of life are expected to continue for some time. Refinements in the idea take account of the social and behavioural aspects of ageing.

The other frontiers of science.

Frontiers of science are usually considered as those areas where the boundares of human knowledge are being pushed most vigorousl into the unknown. These are the intemal frontiers. But no less important are the external frontiers. Those bordering on the federal govermment, on education, on private industry and on intemational affairs and the developing world are among the most critical and demanding. Some of the outstanding problems facing science, and scientists in these extemal interactions, are discussed within the context of our changing national and international priorities.

Physics.

From massive quarks deep in the hearts of atomic nuclei to the catastrophic collapse of giant stars in the farthest reaches of the universe, from the partial realization of Einstein's dream of a unified theory of the forces of nature to the most practical applications in technology, medicine, and throughout contemporary society, physics continues to have a profound impact on man's view of the universe and on the quality of life. The author argues that the past few years, in terms of new discoveries, new insight-and the new questions-have been among the most productive in the history of the field and puts into context his selection of some of the most important new developments in this fundamental science.

Joint care: what the parents want.

No-one knows better than the parents of mentally handicapped children what facilities should be available for their short-term care, but they are not often asked. The North Tyneside Planning Group for the Mentally Handicapped did ask. Dave Bromley, senior administrative assistant, North Tyneside AHA and Tim Lister, clinical psychologist, Northumberland AHA explain that the results indicate the need for a flexible service.

Axial filament involvement in the motility of Leptospira interrogans.

Motility mutants of Leptospira interrogans serovar illini were isolated and analyzed by dark-field and electron microscopy. Mutants were obtained by screening for small colonies after nitrosoguanidine treatment. One class of mutants did not have hook- or spiral-shaped ends. In addition, the axial filaments from these mutants were not coiled. An analysis of revertants of two of the mutants in this class indicated that the mutations were pleiotropic with respect to motility, hook- and spiral-shaped ends, and axial filament coiling. We conclude that the axial filaments and the hook- and spiral-shaped ends are involved in L. interrogans motility.