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Notes: Waveguided Raman measurements have been performed in order to detect the presence of Ag nanoclusters in soda-lime glass waveguides obtained by ion exchange. By subtracting a strong broadband luminescence and the Raman contribution of the glass matrix, a low frequency Raman peak is resolved. The peak is ascribed to surface acoustic vibrations of silver clusters. The involved modes are the quadrupolar spheroidal ones. The size distribution of the Ag clusters is deduced from the energy and the linewidth of the peak. Silver particles have small dimensions with an upper size limit of about 1.5 nm. This result is in good agreement with recent transmission electron microscopy measurements. © 1996 American Institute of Physics.

Notes: The low-frequency magnetic flux noise in thin-film rings of YBa2Cu3O7−δ (YBCO) is measured over the temperature range 1.3–125 K by means of a dc superconducting quantum interference device (SQUID) maintained at liquid-helium temperatures. Below the transition temperature Tc of the YBCO, the spectral density of the noise scales as 1/f, where f is the frequency, and generally increases with increasing temperature. The magnitude of the noise depends strongly on the microstructure of the film, and is lowest for a sample which is predominantly oriented with its c axis perpendicular to the substrate. These results imply that SQUID's and flux transformers of YBCO must be fabricated from highly oriented films to produce good resolution at low frequencies.

Notes: Using a dc superconducting quantum interference device (SQUID) at 4.2 K, we have measured the magnitude and temperature dependence of the flux noise generated by superconducting flux transformers made from YBa2Cu3O7−x. If the transformer loop is opened, the observed noise decreases by a factor of 10, demonstrating that moving vortices generate noise primarily by altering the screening current, rather than by coupling their magnetic flux directly into the SQUID. Model calculations are given for the various noise contributions, and shown to be reasonable predictions of the observed effects.

Notes: Using a three-layer YBa2Cu3O7−x-SrTiO3-YBa2Cu3O7−x in situ laser deposition process, we have constructed thin-film flux transformers which have pickup loops 10 mm on a side and input coils with ten turns. Each layer was patterned with a shadow mask or photolithography. The flux transformers were inductively coupled to a dc superconducting quantum interference device (SQUID) at 4.2 K to determine their transition temperature, and the temperature dependence of their critical current and coupling efficiency. The best flux transformer had a transition temperature of 77 K, and enhanced the magnetic field response of the SQUID by a factor of 9.5.

Notes: Seeded supersonic beams of oligothiophenes have been developed and used to grow very high quality films on CaF2 and SiO2. Optical characterizations show features previously observed only on single crystals and very thin films. In particular, the vibronic progression of the 0–0 transition is well resolved at 10 K. Highly supersonic beams give best results. High quality films are produced over a range of thicknesses ≥500 nm. The correlation between properties of the films and beam parameters are discussed. The energy state of oligomers is envisaged to play a key role in the growth. © 2000 American Institute of Physics.

Notes: In graded-index planar optical waveguides, different guided modes propagate in layers with different thickness. By comparison of spectra (Raman, luminescence) taken by waveguide excitation in different modes, it is possible to characterize the guide at different depths. The method has been applied to waveguides obtained by ion exchange of silver in a soda-lime substrate. Luminescence from silver ions and Raman scattering from the optical vibrations of the glass and from the acoustic vibrations of silver nanoclusters depend on the silver concentration, providing different spectra for excitation in different modes of the guide. © 1999 American Institute of Physics.

Notes: Background: Advances in paediatric intensive care have reduced mortality but, unfortunately, one of the consequences is an increase in the number of patients with chronic diseases. It is generally agreed that home care of children requiring ventilatory support improves their outcomes and results in cost saving for the National Health Service. Methods: Since 1985, the Children's Hospital Bambino Gesù of Rome has developed a program of paediatric home care. The program is performed by a committed Home Health Care Team (HHCT) which selects the eligible patients for home care and trains the families to treat their child. During the period January 1985 to January 2001, 53 children with chronic respiratory failure were included in the home care program. Of these, seven patients were successively excluded and six died in our intensive care unit (ICU), while one still lives in our ICU since 1997. The results obtained in the remaining 46 children are reported. Results: The pathologies consisted of disorders of respiratory control related to brain damage (26%), upper airways obstructive disease (26%), spinal muscular atrophy (22%), myopathies and muscular dystrophies (6.5%), bronchopulmonary dysplasia (6.5%), tracheomalacia (6.5%), central hypoventilation syndrome (4.3%) and progressive congenital scoliosis (2.2%). Of these 46 patients, 34 children are mechanically ventilated and the median of their ICU stay was 109.5 days (range 54–214 days), while the remaining 12 children were breathing spontaneously and the median of their ICU stay was 90.5 days (range 61–134 days). We temporarily readmitted six patients to our ICU to perform scheduled otolaryngological surgery, eight patients for acute respiratory infections and two patients for deterioration of their neurological status due to high pressure hydrocephalus for placement of a ventriculoperitoneal shunt; these 16 patients were discharged back home again. Two other patients were readmitted for deterioration of their chronic disease and died in our ICU, while seven patients died at home. Conclusions: Thirty-seven children are still alive at home and four of them improved their respiratory condition so that it was possible to remove the tracheostomy tube. Our oldest patient has now achieved 15 years of mechanical ventilation at home.

Notes: Background:  Variations in the prevalence of respiratory symptoms according to geo-climatic factors could provide important clues to the knowledge of the aetiology of asthma.Methods:  Geo-climatic variations in the prevalence of current asthma, allergic rhinitis and chronic cough, and phlegm were assessed on a random sample of 18 873 subjects (response rate = 72.7%) from different climatic regions of Italy. An ecological analysis, supported by robust statistical methods, was employed to investigate potential trends.Results:  The prevalence of all symptoms was significantly heterogeneous throughout the peninsula. Only asthma-like symptoms showed a north–south trend: the prevalence increased at a decreasing latitude [odds ratio (OR) varies from 0.92 to 0.96, P 〈 0.05], at a decreasing distance from the sea (OR: 0.90–0.93 for 30 km distance, P 〈 0.05), at higher annual mean temperatures (OR: 1.11–1.14, P 〈 0.05) and at smaller annual temperature ranges (OR: 0.94–0.95, P 〈 0.05). Of the geo-climatic variables considered, temperature range had the greatest influence on most asthma-like symptoms. No association was found between geo-climatic variables and allergic rhinitis or chronic cough and phlegm.Conclusions:  Asthma prevalence seems to be significantly affected by climate as asthma-like symptoms were more common in central-southern Italy, with a Mediterranean climate, than in areas with a continental climate (northern Italy).

Notes: Abstract: Several species of cetaceans naturally slough visible quantities of skin. We have investigated the prospect of using this material as a viable alternative to the use of biopsy darts for the collection of samples for molecular analysis. Pieces of skin were collected from free-ranging individuals of three different species—the humpback (Megaptera novaeangliae), sperm (Physeter macrocephalus) and right whales (Eubalaena glacialis). DNA was extracted from 11 pieces of sloughed skin and DNA “fingerprint” profiles prepared. All samples contained DNA of both sufficient quality and quantity for genetic analysis. The applicability of this approach is discussed generally in relation to answering problems about the population structure and breeding systems of cetaceans.