Random fields of multivariate test statistics, with applications to shape analysis

Our data are random fields of multivariate Gaussian observations, and we fit a multivariate linear model with common design matrix at each point. We are interested in detecting those points where some of the coefficients are nonzero using classical multivariate statistics evaluated at each point. The problem is to find the $P$-value of the maximum of such a random field of test statistics. We approximate this by the expected Euler characteristic of the excursion set. Our main result is a very simple method for calculating this, which not only gives us the previous result of Cao and Worsley [Ann. Statist. 27 (1999) 925--942] for Hotelling's $T^2$, but also random fields of Roy's maximum root, maximum canonical correlations [Ann. Appl. Probab. 9 (1999) 1021--1057], multilinear forms [Ann. Statist. 29 (2001) 328--371], $\bar{\chi}^2$ [Statist. Probab. Lett 32 (1997) 367--376, Ann. Statist. 25 (1997) 2368--2387] and $\chi^2$ scale space [Adv. in Appl. Probab. 33 (2001) 773--793]. The trick involves approaching the problem from the point of view of Roy's union-intersection principle. The results are applied to a problem in shape analysis where we look for brain damage due to nonmissile trauma.Comment: Published in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Radio and X-ray observations of an exceptional radio flare in the extreme z=4.72 blazar GB B1428+4217

We report on the extreme behaviour of the high redshift blazar GB B1428+4217 at z=4.72. A continued programme of radio measurements has revealed an exceptional flare in the lightcurve, with the 15.2 GHz flux density rising by a factor ~3 from ~140 mJy to ~430 mJy in a rest-frame timescale of only ~4 months -- much larger than any previous flares observed in this source. In addition to new measurements of the 1.4-43 GHz radio spectrum we also present the analysis and results of a target-of-opportunity X-ray observation using XMM-Newton, made close to the peak in radio flux. Although the X-ray data do not show a flare in the high energy lightcurve, we are able to confirm the X-ray spectral variability hinted at in previous observations. GB B1428+4217 is one of several high-redshift radio-loud quasars that display a low energy break in the X-ray spectrum, probably due to the presence of excess absorption in the source. X-ray spectral analysis of the latest XMM-Newton data is shown to be consistent with the warm absorption scenario which we have hypothesized previously. Warm absorption is also consistent with the observed X-ray spectral variability of the source, in which the spectral changes can be successfully accounted-for with a fixed column density of material in which the ionization state is correlated with hardness of the underlying power-law emission.Comment: 8 pages, 5 figures, MNRAS accepte

Regional innovation in arts provision spawned by COVID-19: ‘It became a lifeline for a lot of people who are stuck at home’

Although the impact of the global COVID-19 pandemic on the arts and cultural sector due to the closure of galleries, museums, arts venues, and other cultural assets represents a significant health risk, new opportunities for arts and cultural engagement have arisen. Interviews with 24 representatives including service providers and creative practitioners from 15 arts and cultural organizations within the Liverpool City Region were conducted. The aim was to examine the impact of COVID-19 on arts and cultural provision and on organizations and people providing these services, as well as to understand the perceptions of service providers and practitioners of the effects on those whom arts and cultural organizations serve, including those who would usually access arts through formal healthcare routes (e.g., through collaboration with health partners). Interview data were analyzed using framework analysis. Four overarching themes were identified: Response: Closures, adaptations, and new directions; Challenges of online provision; Value of online provision; and the future of the arts. The arts and cultural sector has innovated rapidly, notably with accelerated digitalisation. Alternative provision has been “a lifeline” for vulnerable groups, such as those with mental health difficulties. Arts organizations have been most effective in reaching vulnerable, isolated and disadvantaged populations when they have worked in close collaboration with health and social care providers. The implementation of hybrid provision is an important move forward for the sector in light of our findings that alternative modes of provision are advantageous additions to service as usual. Given the increasing concerns about the mental health sequelae of the pandemic in the UK, arts and cultural engagement could play a pivotal role in the future recovery period

An analysis of HCPC fitness to practise hearings: Fit to Practise or Fit for Purpose?

All professions regulated by the HCPC have ‘protection of title’. This means that only those on its relevant register can legally work as or call themselves a social worker. As such, the HCPC’s Fitness to Practise panel wields a lot of power over individuals brought before it, effectively being able to prevent them from gaining employment as a social worker or imposing conditions on their practice. This article reports the findings from a study which examined publically available notes of HCPC fitness to practise hearings. The aim was to analyse what happens when an initial investigation finds that there is a case to answer, what factors influence the findings of the Fitness to Practise panel and how the outcome of the hearing then affects the social worker subject to the HCPC process. Using thematic analysis, our findings suggest that the seriousness of the alleged misconduct does not necessarily relate to the severity of sanction applied. It is the social worker’s engagement with the process, her insight into the issues and her credibility as a witness that appears to have the most significant bearing on the level of sanction applied

Tilted Euler characteristic densities for Central Limit random fields, with application to "bubbles"

Local increases in the mean of a random field are detected (conservatively) by thresholding a field of test statistics at a level $u$ chosen to control the tail probability or $p$-value of its maximum. This $p$-value is approximated by the expected Euler characteristic (EC) of the excursion set of the test statistic field above $u$, denoted $\mathbb{E}\varphi(A_u)$. Under isotropy, one can use the expansion $\mathbb{E}\varphi(A_u)=\sum_k\mathcal{V}_k\rho_k(u)$, where $\mathcal{V}_k$ is an intrinsic volume of the parameter space and $\rho_k$ is an EC density of the field. EC densities are available for a number of processes, mainly those constructed from (multivariate) Gaussian fields via smooth functions. Using saddlepoint methods, we derive an expansion for $\rho_k(u)$ for fields which are only approximately Gaussian, but for which higher-order cumulants are available. We focus on linear combinations of $n$ independent non-Gaussian fields, whence a Central Limit theorem is in force. The threshold $u$ is allowed to grow with the sample size $n$, in which case our expression has a smaller relative asymptotic error than the Gaussian EC density. Several illustrative examples including an application to "bubbles" data accompany the theory.Comment: Published in at http://dx.doi.org/10.1214/07-AOS549 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Probability distribution of the maximum of a smooth temporal signal

We present an approximate calculation for the distribution of the maximum of a smooth stationary temporal signal X(t). As an application, we compute the persistence exponent associated to the probability that the process remains below a non-zero level M. When X(t) is a Gaussian process, our results are expressed explicitly in terms of the two-time correlation function, f(t)=.Comment: Final version (1 major typo corrected; better introduction). Accepted in Phys. Rev. Let

Back to live: Returning to in-person engagement with arts and culture in the Liverpool City Region

On July 19th 2021, the UK government lifted the COVID-19 restrictions that had been in place since March 2020, including wearing masks, social distancing, and all other legal requirements. The return to in-person events has been slow and gradual, showing that audiences are still cautious when (and if) they resume engaging in arts and culture. Patterns of audience behavior have also changed, shifting toward local attendance, greater digital and hybrid engagement, and openness to event format changes. As the arts and cultural industry recovers from the pandemic, it is important to adopt an audience-oriented approach and look at the changing patterns of engaging in arts and culture. This study aims to better understand the impact of the pandemic on the patterns of cultural and arts engagement. Eight qualitative interviews were conducted to explore the changes in arts and cultural engagement since the restrictions were lifted, focusing particularly on the audience’s experiences of returning to in-person arts and cultural events in the Liverpool City Region (LCR). Using framework analysis, three themes were identified from the data: The new normal: reframing pre-pandemic and pandemic experiences of arts and culture, Re-adjusting to in-person provision, and Moving forward: online and blended provision. The findings show that the pandemic altered the ways that people engage in arts and culture. The “new normal,” a blend of pandemic and pre-pandemic experiences, illustrates how the pandemic has highlighted and reconfigured the importance of arts and culture, in terms of personal and cultural identity. Resuming in-person engagement after a long break, participants noted that they were able to feel more like themselves again. Arts and culture were perceived to be beneficial in rebuilding personal resilience and confidence. Engaging in arts and culture, following the isolating experience of the pandemic, has also helped participants feel reconnected to others through their shared experiences. Finally, the findings suggest that online provision remains vital for many, ensuring wider inclusivity, particularly for vulnerable audiences. At the same time, it is important to acknowledge the barriers to online inclusion and the possibility of this resulting in a growing digital divide

Income differences in food consumption in the 1995 Australian national nutrition survey

Objective: To assess the relationships between an index of per capita income and the intake of a variety of individual foods as well as groups of food for men and women in different age groups. Design: Cross-sectional national survey of free-living men and women. Subjects: A sample of 5053 males and 5701 females aged 18 y and over who completed the Australian National Nutrition Survey 1995. Methods: Information about the frequency of consumption of 88 food items was obtained. On the basis of scores on the Food Frequency Questionnaire, regular and irregular consumers of single foods were identified. The relationships between regularity of consumption of individual foods and per capita income were analysed via contingency tables. Food variety scores were derived by assigning individual foods to conventional food group taxonomies, and then summing up the dichotomised intake scores for individual foods within each food group. Two-way ANOVA (income age group) were performed on the food variety scores for males and females, respectively. Results: Per capita income was extensively related to the reported consumption of individual foods and to total and food group variety indices. Generally, both men and women in low income households had less varied diets than those in higher-income households. However, several traditional foods were consumed less often by young high-income respondents, especially young women. Conclusions: Major income differentials in food variety occur in Australia but they are moderated by age and gender. Younger high-income women, in particular, appear to have rejected a number of traditional foods, possibly on the basis of health beliefs. The findings also suggest that data aggregation has marked effects on income and food consumption relationships.<br /