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We assessed evidence of exposure to viruses and bacteria in an unmanaged and long-isolated population of Soay sheep (Ovis aries) inhabiting Hirta, in the St Kilda archipelago, 65 km west of Benbecula in the Outer Hebrides of Scotland. The sheep harbour many metazoan and protozoan parasites but their exposure to viral and bacterial pathogens is unknown. We tested for herpes viral DNA in leucocytes and found that 21 of 42 tested sheep were infected with ovine herpesvirus 2 (OHV-2). We also tested 750 plasma samples collected between 1997 and 2010 for evidence of exposure to seven other viral and bacterial agents common in domestic Scottish sheep. We found evidence of exposure to Leptospira spp., with overall seroprevalence of 6·5%. However, serological evidence indicated that the population had not been exposed to border disease, parainfluenza, maedi-visna, or orf viruses, nor to Chlamydia abortus. Some sheep tested positive for antibodies against Mycobacterium avium subsp. paratuberculosis (MAP) but, in the absence of retrospective faecal samples, the presence of this infection could not be confirmed. The roles of importation, the pathogen–host interaction, nematode co-infection and local transmission warrant future investigation, to elucidate the transmission ecology and fitness effects of the few viral and bacterial pathogens on Hirta.
Periodic solutions of certain one-dimensional non-autonomous differential equations are investigated (equation (1.4)); the independent variable is complex. The motivation, which is explained in the introductory section, is the connection with certain polynomial two-dimensional systems. Several classes of coefficients are considered; in each case the aim is to estimate the maximum number of periodic solutions into which a given solution can bifurcate under perturbation of the coefficients. In particular, we need to know when there is a full neighbourhood of periodic solutions. We give a number of sufficient conditions and investigate the implications for the corresponding two-dimensional systems.
are considered, where P and Q are polynomials. The question of interest is the maximum possible numberof limit cycles of such systems in terms of the degree of P and Q. An algorithm is described for determining a so-called focal basis; this can be implemented on a computer. Estimates can then be obtained for the number of small-amplitude limit cycles. The technique is applied to certain cubic systems; a class of examples with exactly five small-amplitude limit cycles is constructed. Quadratic systems are also considered.
Suppose that f: ℝ×ℂN→ℂN is holomorphic in z and continuous in t, and that Φ: ℂN×ℂN→ℂN is holomorphic. Boundary value problems of the form
are considered. The particular interest is in the structure and topological properties of the set of solutions. The paper is motivated by the corresponding properties of the set of periodic solutions of ż = f(t, z) when f is periodic in t. Consideration of this complex equation gives information about the periodic solutions of the real equation ẋ = f(t, x).
Measurements and theory are presented examining the relationship between mobility and doping in regioregular poly(3-hexylthiophene) (P3HT). Mobility is found to increase super-linearly with doping and is comparable to models reported for other conjugated polymers. Schottky measurements have been used to calculate the doping density and bulk mobility of regioregular P3HT. Aluminium Schottky contacts showed signs of native oxide disrupting current flow through the device. This effect was observed to degrade further with the introduction of dopant into the polymer. Titanium devices show a general shift of the Schottky characteristic to higher current levels with increased dopant. Field effect mobility of P3HT films was also calculated using thin-film transistor (TFT) structures. The field effect mobility values were observed to be more than two orders of magnitude higher than the bulk mobility value. The addition of dopant also increased gate leakage currents in TFT devices. The increased conductivity in doped polymer can increase off currents in the device; this is avoided by using Schottky contacts as the source and drain. Preliminary results on Schottky contact TFTs are also presented as well as a description of the operation of such a device.
In situ ellipsometry at selected wavelengths in the spectral range 280 nm to 1000 nnn was performed during the rf bias assisted electron cyclotron resonance (ECR) etching of bulk silicon, GaAs, InP, and GaAs/AlGaAs/GaAs, and InGaAs/InP layered strcutures by a CCl2F2 based etch gas.
While real time thickness changes for bulk materials cannot be determined ellipsometrically, some insight into the etch mechanism may be gained by observing the effect of the process on the surface dynamically, and after the etch process has been completed. Monitoring of the layered structures during etching can provide a real time measure of the amount of material remaining in the layer being etched, and provide tight process control.
TiN/NbN multilayers and TiN monolithic films have been grown by UHV reactive magnetron sputter deposition on MgO single crystals. The hardness has been measured by nanoindentation and the as-deposited and deformed structures studied in cross-section using transmission electron microscopy. It has been found that initially the multilayers grow epitaxially with the substrate. However, once the overall film thickness has reached ∼300 nm, epitaxial growth ceases. No increase in hardness with respect to monolithic films of the multilayer components is observed in these multilayers. Experiments on monolithic films of TiN show that the same loss of epitaxy occurs, leading to a reduction in the hardness of the films, and that this change in growth morphology is triggered by the internal stresses induced within the films during deposition.
Differences in the content of care provided by acute in-patient mental health wards and residential crisis services such as crisis houses have not been researched.
To compare planned and actual care provided at alternative and standard acute wards and to investigate the relationship between care received and patient satisfaction.
Perspectives of stakeholders, including local service managers, clinicians and commissioners, were obtained from 23 qualitative interviews. Quantitative investigation of the care provided at four alternative and four standard services was undertaken using three instruments developed for this study. The relationship of care received to patient satisfaction was explored.
No significant difference was found in intensity of staff– patient contact between alternative and standard services. Alternative services provided more psychological and less physical and pharmacological care than standard wards. Care provision may be more collaborative and informal in alternative services. All measured types of care were positively associated with patient satisfaction. Measured differences in the care provided did not explain the greater acceptability of community alternatives.
Similarities in care may be more marked than differences at alternative and standard services. Staff–patient contact is an important determinant of patient satisfaction, so increasing it should be a priority for all acute in-patient services.
Key questions regarding residential alternatives to standard acute psychiatric care, such as crisis houses and short-stay in-patient units, concern the role that they fulfil within local acute care systems, and whether they manage people with needs and illnesses of comparable severity to those admitted to standard acute wards.
To study the extent to which people admitted to residential alternatives and to standard acute services are similar, and the role within local acute care systems of admission to an alternative service.
Our approach combined quantitative and qualitative methods. Consecutive cohorts of patients in six residential alternatives across England and six standard acute wards in the same areas were identified, and clinical and demographic characteristics, severity of symptoms, impairments and risks compared. Semi-structured interviews with key stakeholders in each local service system were used to explore the role and functioning of each alternative.
Being already known to services (OR = 2.6, 95% CI 1.3–5.2), posing a lower risk to others (OR = 0.49, 95% CI 0.31–0.78) and having initiated help-seeking in the current crisis (OR = 2.2, 95% CI 1.2–4.3) were associated with being admitted to an alternative rather than a standard service. Stakeholder interviews suggested that alternatives have a role that is similar but not identical to standard hospital services. They can divert some, but not all, patients from acute admission.
Residential alternatives are integrated into catchment area mental health systems. They serve similar, but not identical, clinical populations to standard acute wards and provide some, but not all, of the functions of these wards.
To evaluate individuals at high risk for tuberculosis exposure who had a history of a positive tuberculin skin test (TST) result in order to determine the prevalence of unsuspected negative TST results. To confirm these findings with the QuantiFERON-TB test (QFT), an in vitro whole-blood assay that measures tuberculin-induced secretion of interferon-γ.
This survey was conducted from November 2001 through December 2003 at 3 sites where TST screening is regularly done. Detailed histories and reviews of medical records were performed. TSTs were placed and read by 2 experienced healthcare workers, and blood was drawn for QFT. Any subject with a negative result of an initial TST during the study (induration diameter, <10 mm) underwent a second TST and a second QFT. The TST-negative group comprised individuals for whom both TSTs had an induration diameter of <10 mm. The confirmed-negative group comprised individuals for whom both TSTs yielded no detectable induration and results of both QFTs were negative.
A total of 67 immunocompetent subjects with positive results of a previous TST were enrolled in the study. Of 56 subjects who completed the TST protocol, 25 (44.6%; 95% confidence interval [CI], 31.6%-57.6%) were TST negative (P<.001). Of 31 subjects who completed the TST protocol and the QFT protocol, 8 (25.8%; 95% CI, 10.4%-41.2%) were confirmed negative (P<.005).
A significant proportion of subjects with positive results of a previous TST were TST negative in this study, and a subset of these were confirmed negative. These individuals' TST status may have reverted or may never have been positive. It will be important in future studies to determine whether such individuals lack immunity to tuberculosis and whether they should be considered for reentry into tuberculosis screening programs.
Electron beam evaporated Ni thin films are found to have tensile stress of 1.2 Gpa. The stress is relieved upon heating, accompanied by grain growth. The calculated stress matches the experimental result and a mechanism of grain growth is proposed.
The electromigration performance of samples fabricated with new Al via-filling techniques are studied and compared. The new techniques are (1) Hot Al mono-chamber and (2) CVD/PVD Al. Their electromigration performances are assessed over a range of stress conditions and compared with that of a standard W- etchback technique.
A prospective study was carried out on 25 consecutive patients referred to an outpatient clinic at The Royal National Throat, Nose and Ear Hospital, with a medical letter suggestive of sinusitis, to test the hypothesis that the diagnosis of inflammatory sinus disease could be made simply and accurately by employing systematic nasal endoscopy and a series of plain sinus X-rays.
The study compared the diagnostic yields of the history, rigid nasal endoscopy and plain sinus films with computed tomography. All the investigations were performed on the same day. The interobserver variability between consultant ENT surgeon, senior registrar and registrar were compared.
With heightened concern over the radiation exposure patients are receiving for medical investigations, the radiation exposure was determined for a selected group of patients. This study demonstrated that in the diagnosis of inflammatory sinonasal disease the clinical assessment correlated with the CT findings in over 90 per cent of cases. This accuracy was dependent on the experience of the clinician in using rigid nasal endoscopy. Interobserver variability ranged from 71 to 90.4 per cent in the correct diagnosis of underlying sinus disease. Close agreement was seen with the interpretation of CT scans. The concordance rate between plain films and CT scans was 87 per cent when reported by a consultant radiologist. This is in close agreement with previously reported studies. The average radiation exposure of coronal CT scanning was 218 times the dose for plain sinus X-rays.
To material scientists the term texture means the crystallographic orientation of grains in a polycrystal. In contrast, geologists use the term more generally to refer to the spatial arrangement or association of mineral grains in a rock. In this contribution we are concerned with the materials science definition. There are several established techniques available for the determination of crystallographic textures in rocks. It has also been realised that the scanning electron microscope (SEM) is applicable to the study of crystallographic textures via the electron channelling (EC) effect. This provides an image of mineral/rock microstructure (via orientation contrast), as well as a means of accurately indexing their crystal orientations (via electron channelling patterns, ECP). Both types of EC image result from the relationship between incident electron beam and crystal structure, and the subsequent modulation of the backscattered electron (BSE) emission signal according to Bragg's Law. It is a simple matter to switch between the two imaging modes. A related effect, electron backscattering, provides only the diffraction patterns, but has superior spatial resolution and pattern angles.
Due to crystal symmetry restrictions, there is only a limited range of ECP configurations possible for any mineral. Individual patterns can therefore be identified by comparison with the complete ‘ECP-map’. The location of an individual pattern within the map area is determined by spherical angles, the exact definition of which depends on the type of fabric diagram (e.g. inverse pole figure, pole figure or orientation distribution function). Originally, these angles were measured manually. A computer program (CHANNEL) has been developed which uses a digitisation approach to pattern recognition, derives the required fabric diagrams and also constructs ECP-maps from standard crystal data (i.e. unit cell parameters etc.).
The combination of SEM/EC and CHANNEL dramatically facilitates the study of crystal textures in minerals and rocks, making statistical crystallographic analysis from individual orientations a practicality. The following example applications are considered: (1) crystal structure representation of the Al2SiO5 polymorph system; (2) local crystal texture relationships (epitaxial nucleation) between andalusite and sillimanite grains; (3) bulk rock crystal textures of quartzites; and (4) physical properties (e.g. elastic constants and seismic velocities) determined from bulk rock texture.
A radiological study of skull base anatomy was performed in patients presenting with primary spontaneous CSF rhinorrhoea. Radiology correctly identified the fistula site in 90 per cent of cases. Contrast CT imaging was found to be the most suitable technique for identifying the presence and site of CSF fistulae. However, pre-contrast bony dehiscences were identified in all patients leaking from the cribriform plate region. More significantly, all of these patients showed deviation of their crista galli, a radiological sign hitherto unreported. These findings support the theory that congenital bony dehiscence is the aetiological basis for this condition. The importance of radiology in the management of this condition is emphasized.
There is an extensive literature on Liénard's equation
and numerous criteria for the existence of limit cycles have been developed: see the survey of Staude, for example. Broadly speaking, such results are proved in one of two ways: a bounded solution is shown to exist and the Poincaré–Bendixson theorem used, or an ‘a priori’ bound for periodic solutions is obtained and the methods of degree theory utilized.