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The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.
In comparative-historical analysis, countries are always different places before critical junctures set them on divergent pathways. By comparing the legacies of politicized ethnic diversity for the construction of state infrastructural power in Latin America and Southeast Asia, we elaborate the methodological and substantive importance of these “critical antecedents.” The critical antecedent in each region was the inheritance at independence of a sharp indigenous cleavage. This indigenous inheritance shaped threat perceptions and state-society coalitions in both regions in similarly powerful path-dependent ways—yet in intriguingly divergent directions. A salient indigenous cleavage hindered but did not preclude state building in nineteenth-century Peru, while fostering but not predestining state building in post–World War II Malaysia. Divergent levels of postcolonial state infrastructural power thus exhibit deep if indirect foundations in the identity cleavages inherited from preindependence eras. This cross-region comparative exploration highlights the analytical leverage gained from systematically incorporating preexisting cross-case differences into critical juncture accounts.
Greenland's marine-terminating glaciers may be sensitive to oceanic heat, but the fjord processes controlling delivery of this heat to glacier termini remain poorly constrained. Here we use a three-dimensional numerical model of Kangerdlugssuaq Fjord, East Greenland, to examine controls on fjord/shelf exchange. We find that shelf-forced intermediary circulation can replace up to ~25% of the fjord volume with shelf waters within 10 d, while buoyancy-driven circulation (forced by subglacial runoff from marine-terminating glaciers) exchanges ~10% of the fjord volume over a 10 d period under typical summer conditions. However, while the intermediary circulation generates higher exchange rates between the fjord and shelf, the buoyancy-driven circulation is consistent over time hence more efficient at transporting water along the full length of the fjord. We thus find that buoyancy-driven circulation is the primary conveyor of oceanic heat to glaciers during the melt season. Intermediary circulation will however dominate during winter unless there is sufficient input of fresh water from subglacial melting. Our findings suggest that increasing shelf water temperatures and stronger buoyancy-driven circulation caused the heat available for melting at Kangerdlugssuaq Glacier to increase by ~50% between 1993–2001 and 2002–11, broadly coincident with the onset of rapid retreat at this glacier.
Persecutory delusions may be unfounded threat beliefs maintained by
safety-seeking behaviours that prevent disconfirmatory evidence being
successfully processed. Use of virtual reality could facilitate new
To test the hypothesis that enabling patients to test the threat
predictions of persecutory delusions in virtual reality social
environments with the dropping of safety-seeking behaviours (virtual
reality cognitive therapy) would lead to greater delusion reduction than
exposure alone (virtual reality exposure).
Conviction in delusions and distress in a real-world situation were
assessed in 30 patients with persecutory delusions. Patients were then
randomised to virtual reality cognitive therapy or virtual reality
exposure, both with 30 min in graded virtual reality social environments.
Delusion conviction and real-world distress were then reassessed.
In comparison with exposure, virtual reality cognitive therapy led to
large reductions in delusional conviction (reduction 22.0%,
P = 0.024, Cohen's d = 1.3) and
real-world distress (reduction 19.6%, P = 0.020, Cohen's
d = 0.8).
Cognitive therapy using virtual reality could prove highly effective in
Methylation of the fragile X mental retardation 1 (FMR1) exon 1/intron 1 boundary positioned fragile X related epigenetic element 2 (FREE2), reveals skewed X-chromosome inactivation (XCI) in fragile X syndrome full mutation (FM: CGG > 200) females. XCI skewing has been also linked to abnormal X-linked gene expression with the broader clinical impact for sex chromosome aneuploidies (SCAs). In this study, 10 FREE2 CpG sites were targeted using methylation specific quantitative melt analysis (MS-QMA), including 3 sites that could not be analysed with previously used EpiTYPER system. The method was applied for detection of skewed XCI in FM females and in different types of SCA. We tested venous blood and saliva DNA collected from 107 controls (CGG < 40), and 148 FM and 90 SCA individuals. MS-QMA identified: (i) most SCAs if combined with a Y chromosome test; (ii) locus-specific XCI skewing towards the hypomethylated state in FM females; and (iii) skewed XCI towards the hypermethylated state in SCA with 3 or more X chromosomes, and in 5% of the 47,XXY individuals. MS-QMA output also showed significant correlation with the EpiTYPER reference method in FM males and females (P < 0.0001) and SCAs (P < 0.05). In conclusion, we demonstrate use of MS-QMA to quantify skewed XCI in two applications with diagnostic utility.
Background: Environmental factors have been associated with psychosis but there is little qualitative research looking at how the ongoing interaction between individual and environment maintains psychotic symptoms. Aims: The current study investigates how people with persecutory delusions interpret events in a virtual neutral social environment using qualitative methodology. Method: 20 participants with persecutory delusions and 20 controls entered a virtual underground train containing neutral characters. Under these circumstances, people with persecutory delusions reported similar levels of paranoia as non-clinical participants. The transcripts of a post-virtual reality interview of the first 10 participants in each group were analysed. Results: Thematic analyses of interviews focusing on the decision making process associated with attributing intentions of computer-generated characters revealed 11 themes grouped in 3 main categories (evidence in favour of paranoid appraisals, evidence against paranoid appraisals, other behaviour). Conclusions: People with current persecutory delusions are able to use a range of similar strategies to healthy volunteers when making judgements about potential threat in a neutral environment that does not elicit anxiety, but they are less likely than controls to engage in active hypothesis-testing and instead favour experiencing “affect” as evidence of persecutory intention.
To examine whether parents offering a sticker reward to their child to taste a vegetable the child does not currently consume is associated with improvements in children's liking and consumption of the vegetable.
A randomized controlled trial evaluated the effectiveness of exposure only (EO) and exposure plus reward (E + R), relative to a control group, on children's liking and consumption of a target vegetable. Assessments were conducted at baseline and 2 weeks from baseline (post-intervention). Follow-up assessments were conducted at 4 weeks and 3 months from baseline.
The study took place in Adelaide, South Australia. Participants were self-selected in response to local media advertisements seeking to recruit parents finding it difficult to get their children to eat vegetables.
Participants were 185 children (110 boys, seventy-five girls) aged 4–6 years and their primary caregiver/parent (172 mothers, thirteen fathers).
The E + R group was able to achieve more days of taste exposure. Both EO and E + R increased liking at post-intervention compared with control and no further change occurred over the follow-up period. All groups increased their intake of the target vegetable at post-intervention. Target vegetable consumption continued to increase significantly over the follow-up period for E + R and control but not for EO.
The findings provide support for the effectiveness of using a sticker reward with a repeated exposure strategy. In particular, such rewards can facilitate the actual tastings necessary to change liking.
Judging whether we can trust other people is central to social
interaction, despite being error-prone. A fear of others can be instilled
by the contemporary political and social climate. Unfounded mistrust is
called paranoia, and in severe forms is a central symptom of
To demonstrate that individuals without severe mental illness in the
general population experience unfounded paranoid thoughts, and to
determine factors predictive of paranoia using the first laboratory
method of capturing the experience.
Two hundred members of the general public were comprehensively assessed,
and then entered a virtual reality train ride populated by neutral
characters. Ordinal logistic regressions (controlling for age, gender,
ethnicity, education, intellectual functioning, socio-economic status,
train use, playing of computer games) were used to determine predictors
The majority agreed that the characters were neutral, or even thought
they were friendly. However, a substantial minority reported paranoid
concerns. Paranoia was strongly predicted by anxiety, worry, perceptual
anomalies and cognitive inflexibility.
This is the most unambiguous demonstration of paranoid ideation in the
general public so far. Paranoia can be understood in terms of cognitive
factors. The use of virtual reality should lead to rapid advances in the
understanding of paranoia.
Virtual reality provides a means of studying paranoid thinking in
controlled laboratory conditions. However, this method has not been used
with a clinical group
To establish the feasibility and safety of using virtual reality
methodology in people with an at-risk mental state and to investigate the
applicability of a cognitive model of paranoia to this group
Twenty-one participants with an at-risk mental state were assessed before
and after entering a virtual reality environment depicting the inside of
an underground train
Virtual reality did not raise levels of distress at the time of testing
or cause adverse experiences over the subsequent week. Individuals
attributed mental states to virtual reality characters including hostile
intent. Persecutory ideation in virtual reality was predicted by higher
levels of trait paranoia, anxiety, stress, immersion in virtual reality,
perseveration and interpersonal sensitivity
Virtual reality is an acceptable experimental technique for use with
individuals with at-risk mental states. Paranoia in virtual reality was
understandable in terms of the cognitive model of persecutory
Using first principles techniques we have examined the relative physisorption/chemisorption energetics of neutral molecular water and oxygen at the most thermodynamically stable surface (110) of tin dioxide. We find that water binds more strongly to the perfect surface at 5 co- ordinate tin sites than oxygen. However, binding of both water and oxygen at bridging oxygen vacancies in the defective surface is comparable. In the context of gas-sensing behaviour at moderate temperatures (∼300K), we propose that the Mars and van Krevelen  re-oxidation reaction will slow when the partial pressure of water is high, since the number of favourable adsorption sites will effectively decrease. In addition, one would expect that the surface conductivity will increase, since the re-oxidation reaction will be hindered.
The distribution of urban peoples and activities among cities of various sizes and characteristics has for a long time interested social critics, town planners, geographers, historians, journalists and some economists in western Europe and the United States. A common theme is that the distribution of urban peoples depends on the distribution of urban jobs. Thus to understand population changes, the analysis of cities usually becomes a study of trends in job location. A decentralized pattern of industrial jobs is thought conducive to a proliferation of small and medium-sized cities. Or to put it the other way, it is often suggested that the concentration of industrial jobs into large cities is a principal explanation of their size.
For more than half a century social critics and theorists have been predicting a coming era of decentralization in manufactures and, as a consequence, of urban peoples. The development of the automobile and of electricity, the use of mass production techniques in specialized single-storey buildings set on large tracts of land, improvements in telecommunications, a high income elasticity of demand for space—all of these have been suggested as forces tending to decentralize manufacturing employment. But what has in fact been the experience of the last half-century?
This paper deals with long-run changes in the structure of Canadian external trade. By structure is meant the magnitude, content, direction, and “terms” of trade. The paper is focused mainly on commodity trade rather than on all international transactions, and on long-run or secular changes rather than on the business cycle or other short-run concerns. The period of study is the “half-century” 1896–1950, and it permits some observation on recent controversies in the theory of international economic adjustment, such as the discussion of Graham's Theory of International Values.