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Certain geological features have been interpreted as evidence of channelized magma flow in the mantle, which is a compacting porous medium. Aharonov et al. (J. Geophys. Res., vol. 100 (B10), 1995, pp. 20433–20450) developed a simple model of reactive porous flow and numerically analysed its instability to channels. The instability relies on magma advection against a chemical solubility gradient and the porosity-dependent permeability of the porous host rock. We extend the previous analysis by systematically mapping out the parameter space. Crucially, we augment numerical solutions with asymptotic analysis to better understand the physical controls on the instability. We derive scalings for the critical conditions of the instability and analyse the associated bifurcation structure. We also determine scalings for the wavelengths and growth rates of the channel structures that emerge. We obtain quantitative theories for and a physical understanding of, first, how advection or diffusion over the reactive time scale sets the horizontal length scale of channels and, second, the role of viscous compaction of the host rock, which also affects the vertical extent of channelized flow. These scalings allow us to derive estimates of the dimensions of emergent channels that are consistent with the geologic record.
Transient Ischaemic Attack (TIA) is a neurologic event with symptom resolution within 24 hours. Early specialist assessment of TIA reduces risk of stroke and death. National United Kingdom (UK) guidelines recommend patients with TIA are seen in specialist clinics within 24 hours (high risk) or seven days (low risk).
We aimed to develop a complex intervention for patients with low risk TIA presenting to the emergency ambulance service. The intervention is being tested in the TIER feasibility trial, in line with Medical Research Council (MRC) guidance on staged development and evaluation of complex interventions.
We conducted three interrelated activities to produce the TIER intervention:
•Survey of UK Ambulance Services (n = 13) to gather information about TIA pathways already in use
•Scoping review of literature describing prehospital care of patients with TIA
•Synthesis of data and definition of intervention by specialist panel of: paramedics; Emergency Department (ED) and stroke consultants; service users; ambulance service managers.
The panel used results to define the TIER intervention, to include:
1.Protocol for paramedics to assess patients presenting with TIA and identify and refer low risk patients for prompt (< 7day) specialist review at TIA clinic
2.Patient Group Directive and information pack to allow paramedic administration of aspirin to patients left at home with referral to TIA clinic
3.Referral process via ambulance control room
4.Training package for paramedics
5.Agreement with TIA clinic service provider including rapid review of referred patients
We followed MRC guidance to develop a clinical intervention for assessment and referral of low risk TIA patients attended by emergency ambulance paramedic. We are testing feasibility of implementing and evaluating this intervention in the TIER feasibility trial which may lead to fully powered multicentre randomized controlled trial (RCT) if predefined progression criteria are met.
A number of copy number variants (CNVs) have been suggested as
susceptibility factors for schizophrenia. For some of these the data
remain equivocal, and the frequency in individuals with schizophrenia is
To determine the contribution of CNVs at 15 schizophrenia-associated loci
(a) using a large new data-set of patients with schizophrenia
(n = 6882) and controls (n = 6316),
and (b) combining our results with those from previous studies.
We used Illumina microarrays to analyse our data. Analyses were
restricted to 520 766 probes common to all arrays used in the different
We found higher rates in participants with schizophrenia than in controls
for 13 of the 15 previously implicated CNVs. Six were nominally
significantly associated (P<0.05) in this new
data-set: deletions at 1q21.1, NRXN1, 15q11.2 and
22q11.2 and duplications at 16p11.2 and the Angelman/Prader–Willi
Syndrome (AS/PWS) region. All eight AS/PWS duplications in patients were
of maternal origin. When combined with published data, 11 of the 15 loci
showed highly significant evidence for association with schizophrenia
We strengthen the support for the majority of the previously implicated
CNVs in schizophrenia. About 2.5% of patients with schizophrenia and 0.9%
of controls carry a large, detectable CNV at one of these loci. Routine
CNV screening may be clinically appropriate given the high rate of known
deleterious mutations in the disorder and the comorbidity associated with
these heritable mutations.
The present study explored parents’ requirements for healthy eating support prior to the development of a tailored intervention.
A cross-sectional study of parents attending children's centres.
Children's centres in Cornwall (rural south-west England) and Islington (urban London borough).
A total of 261 parents (94·2 % female) of pre-school children (aged 2–5 years) completed a questionnaire on factors influencing food choice, and preferences for and views on healthy eating support.
Parents reported that health, taste, freshness and quality were the most important factors influencing their food choices for their pre-school children. The importance of individual factors varied according to level of educational attainment. Over a third (38 %) of parents said they wanted more advice on healthy eating for children. Less educated parents showed the greatest interest in learning more about several aspects: what a ‘healthy diet’ means, how to prepare and cook healthy food, how to understand food labels, budgeting for food, examples of healthy food and snacks for children, appropriate portion sizes for children and ways to encourage children to eat well.
There was demand for healthy eating support among parents of pre-school children, especially those who are less educated, in one rural and one urban area of England.
We created an instructional waiting room video that explained what patients should expect during their emergency department (ED) visit and sought to determine whether preparing patients using this video would 1) improve satisfaction, 2) decrease perceived waiting room times and 3) increase calls to an outpatient referral line in an ambulatory population.
This serial cross-sectional study took place over a period of 2 months before (control) and 2 months after the introduction of an educational waiting room video that described a typical patient visit to our ED. We enrolled a convenience sample of adult patients or parents of pediatric patients who were triaged to the ED waiting room; a research assistant distributed and collected the surveys as patients were being discharged after treatment. Subjects were excluded if they were admitted. The primary outcome was overall satisfaction measured on a 5-point Likert scale, and secondary outcomes included perceived waiting room time, and the number of outpatient referral-line calls.
There were 1132 subjects surveyed: 551 prevideo and 581 postvideo. The mean age was 38 years (standard deviation [SD] 18), 61% were female and the mean ED length of stay was 5.9 hours (SD 3.6). Satisfaction scores were significantly higher postvideo, with 65% of participants ranking their visit as either “excellent” or “very good,” compared with 58.1% in the prevideo group (p = 0.019); however, perceived waiting room time was not significantly different between the groups (p = 0.24). Patient calls to our specialty outpatient clinic referral line increased from 1.5 per month (95% confidence interval [CI] 0.58–2.42) to 4.5 per month (95% CI 1.19–7.18) (p = 0.032). After adjusting for possible covariates, the most significant determinants of overall satisfaction were perceived waiting room time (odds ratio [OR] 0.41, 95% CI 0.34–0.48) and having seen the ED waiting room video (OR 1.41, 95% CI 1.06–1.86).
Preparing patients for their ED experience by describing the ED process of care through a waiting room video can improve ED patient satisfaction and the knowledge of outpatient clinic resources in an ambulatory population. Future studies should research the implementation of this educational intervention in a randomized fashion.
There is now compelling evidence that many neurological disorders which become apparent after birth have their origins during fetal life. For example, epidemiological studies have shown that cerebral palsy, a heterogeneous group of non-progressive motor impairment disorders, most frequently results from prenatal rather than perinatal or postnatal causes (Nelson and Ellenberg 1986). Minimal cerebral brain dysfunction, typified by children having general reading, writing and cognitive problems, is often associated with intrauterine growth restriction (IUGR), suggesting that the neurological problems have their origins in utero. Schizophrenia, one of the most debilitating of mental disorders, affecting about 1% of the population, cannot be accounted for entirely by genetic inheritance. On the basis of histological and neurochemical observations it has been proposed that prenatal insults result in a vulnerability of the developing brain, predisposing an individual with risk factors (seen as genetic inheritance) to develop the symptoms of schizophrenia in the teenage or young adult years (Akil and Weinberger 2000). Other disorders such as epilepsy and autism are also thought to result in part from neurodevelopmental deficits. Thus there is growing evidence that abnormal development of the brain during gestation contributes to many neurological disorders which manifest in later life.
Over the last few decades there have been major advances in our understanding of the intricate sequence of events that results in the formation of the entire nervous system from a specialised sheet of cells on the dorsal surface of the embryo.
The class of co-context-free groups is studied. A co-context-free group is defined as one whose co-word problem (the complement of its word problem) is context-free. This class is larger than the subclass of context-free groups, being closed under the taking of finite direct products, restricted standard wreath products with context-free top groups, and passing to finitely generated subgroups and finite index overgroups. No other examples of co-context-free groups are known. It is proved that the only examples amongst polycyclic groups or the Baumslag–Solitar groups are virtually abelian. This is done by proving that languages with certain purely arithmetical properties cannot be context-free; this result may be of independent interest.
Whilst clinical psychologists and a few fellow professionals have long known the importance of psychology in rehabilitation, it has recently been formally acknowledged as an essential professional discipline in such settings. In relation to stroke care for example, the recently published National Service Framework for Older Adults, England (NSFOA) specifies (Standard Five) that multidisciplinary stroke rehabilitation teams should include clinical psychologists, a view that is echoed in the Royal College of Physicians’ ‘Guidelines for Stroke Care’. The NSF is not yet universal to all areas of the UK, however, this article will reflect the English NSF as appropriate
standards for health care across the country.
Conjugated light-emitting polymers (LEPs) have real potential to serve as the active layer in a new generation of emissive displays. Emerging as lead candidates for first-generation displays are poly(1,4-phenylene vinylene)s (PPVs) and poly(9,9-dialkylfluorene)s, as well as other polyaromatic materials. The poly(fluorene)s are at present the most commercially developed of these LEP materials for red–green–blue (RGB) applications. The low power consumption of LEP devices in general makes them particularly suited to mobile applications. Combining solution-processable emissive polymers with direct-patterning methods such as ink-jet printing will lead to the possibility of low-cost, high-resolution displays. The synthesis and properties of PPVs and poly(9,9-dialkylfluorene)s are briefly reviewed in this article, with a major focus on recent developments.
Women who are positive for thyroid antibodies in early gestation are prone to post-partum depression, apparently independent of thyroid dysfunction, as measured by serum levels of free thyroxine, free triodothyroxine and thyroid-stimulating hormone. This finding may be due to infrequent monitoring of thyroid function, because hyperthyroidism, hypothyroidism and combinations of both may occur post-partum.
To test the hypothesis that stabilising thyroid function post-partum by administering daily thyroxine reduces the rate of occurrence and severity of associated depression.
In a randomised double-blind placebo-controlled trial, 100 of thyroxine or placebo was given daily to 446 thyroid-antibody-positive women (342 of whom were compliant) from 6 weeks to 6 month spost-partum, assessing their psychiatric and thyroid status at 4-weeklyintervals.
There was no evidence that thyroxine had any effect on the occurrence of depression. The 6-month period prevalence of depression was similar to that reported previously.
The excess of depression in thyroid-antibody-positive women in the post-partum period is not corrected by daily administration of thyroxine.
Despite its inclusion as a basic component of the cognitive-behavioural treatment for panic disorder, the effects of the provision of information about panic anxiety have not been separately assessed. This study compared information-giving with self-monitoring of panic alone, on panic-related variables and negative affect for 40 people with panic disorder. In comparison to self-monitoring alone, information-giving together with self-monitoring was associated with reductions in anticipatory fear of panic and negative affect, but not panic frequency. These results suggest that provision of information about panic anxiety is an important component of the cognitive-behavioural approach to panic disorder in reducing anxious and depressive affect. The other cognitive-behavioural components of this intervention are required to impact upon specific panic parameters.
Australia, with its large continental shelf, requires faster and more economic methods of conducting hydrographic survey. Backed by the Royal Australian Navy an experimental programme to investigate airborne laser methods was commenced in the mid 1970s and completed in 1984. This programme demonstrated that airborne laser depth sounding can be used effectively in Australian coastal waters. This paper reviews the achievements of the experimental programme and describes some features of LADS, a ‘Laser Airborne Depth Sounder’ planned for operational use by the RAN Hydrographic Service. The paper was presented at the Congress of the International Association of Institutes of Navigation, Tokyo, 1–5 October 1985.
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