102 research outputs found

    Herschel PACS and SPIRE observations of blazar PKS 1510-089: a case for two blazar zones

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    We present the results of observations of blazar PKS 1510-089 with the Herschel Space Observatory PACS and SPIRE instruments, together with multiwavelength data from Fermi/LAT, Swift, SMARTS and SMA. The source was found in a quiet state, and its far-infrared spectrum is consistent with a power-law with a spectral index of alpha ~ 0.7. Our Herschel observations were preceded by two 'orphan' gamma-ray flares. The near-infrared data reveal the high-energy cut-off in the main synchrotron component, which cannot be associated with the main gamma-ray component in a one-zone leptonic model. This is because in such a model the luminosity ratio of the External-Compton and synchrotron components is tightly related to the frequency ratio of these components, and in this particular case an unrealistically high energy density of the external radiation would be implied. Therefore, we consider a well-constrained two-zone blazar model to interpret the entire dataset. In this framework, the observed infrared emission is associated with the synchrotron component produced in the hot-dust region at the supra-pc scale, while the gamma-ray emission is associated with the External-Compton component produced in the broad-line region at the sub-pc scale. In addition, the optical/UV emission is associated with the accretion disk thermal emission, with the accretion disk corona likely contributing to the X-ray emission.Comment: 13 pages, 8 figures, 7 tables; accepted for publication in the Astrophysical Journa

    The Dust Trail of Comet 67P/Churyumov-Gerasimenko between 2004 and 2006

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    We report on observations of the dust trail of comet 67P/Churyumov-Gerasimenko (CG) in visible light with the Wide Field Imager at the ESO/MPG 2.2m telescope at 4.7 AU before aphelion, and at 24 micron with the MIPS instrument on board the Spitzer Space Telescope at 5.7 AU both before and after aphelion. The comet did not appear to be active during our observations. Our images probe large dust grains emitted from the comet that have a radiation pressure parameter beta<0.01. We compare our observations with simulated images generated with a dynamical model of the cometary dust and constrain the emission speeds, size distribution, production rate and geometric albedo of the dust. We achieve the best fit to our data with a differential size distribution exponent of -4.1, and emission speeds for a beta=0.01 particle of 25 m/s at perihelion and 2 m/s at 3 AU. The dust production rate in our model is on the order of 1000 kg/s at perihelion and 1 kg/s at 3 AU, and we require a dust geometric albedo between 0.022 and 0.044. The production rates of large (>10 micron) particles required to reproduce the brightness of the trail are sufficient to also account for the coma brightness observed while the comet was inside 3 AU, and we infer that the cross-section in the coma of CG may be dominated by grains of the order of 60-600 micron.Comment: 79 pages, 13 figures, 6 tables. Accepted for publication in Icaru

    What is the impact of structural and cultural factors and interventions within educational settings on promoting positive mental health and preventing poor mental health: a systematic review

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    Mental health (MH) difficulties are on the increase among children and young people (CYP). Evidence has shown that educational settings contain both risk and protective factors for MH. This review investigated which structural and cultural factors and interventions within educational settings promote positive MH and prevent poor MH in 4-18 year olds. Searches were conducted in PsychINFO, Embase, ERIC, ASSIA and British Education Index, and reference lists from key studies and relevant systematic reviews were hand-searched. Intervention, cohort, and qualitative studies were included. Of the 62 included papers, 36 examined cultural factors (30 social/relational and six value-related) while 12 studies examined structural factors (eight organisational and four physical) and 14 studies examined multiple factors. There was strong evidence for the impact of positive classroom management techniques, access to physical activity, and peer mentoring on student MH. Studies examining the impact of positive school culture, teacher training in MH and parent involvement in school MH activities also found predominantly positive results for student MH, albeit the evidence was of lower quality or from a low number of studies. Few studies explicitly examined the impact of interventions on MH inequalities; those that did indicated limited if any reduction to inequalities. A very small number of studies suggested that interventions targeting those at risk of poor MH due to socioeconomic factors could successfully improve wellbeing and reduce depression, anxiety and behavioural problems. Studies exploring the effect of management and leadership strategies within schools, policies, and aspects of the physical environment other than green space were scarce or absent in the literature. This review highlights the need to consider the ways in which educational settings are organised, the culture that is created and the physical space in order to improve the MH of CYP

    Assessing the Feasibility of a Peer Education Project to Improve Mental Health Literacy in Adolescents in the UK

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    Many mental health problems begin in adolescence and occur on a spectrum of severity: early recognition and intervention is important. This study is a quantitative feasibility study of the Mental Health Foundation's Peer Education Project (PEP). Attrition, psychometric properties of questionnaires, indications of improvement on a range of outcomes, and sample size required for a powered trial of effectiveness were assessed. 203 students completed the survey both pre and post-intervention. It was found that existing previously-validated measures had good psychometric properties, with two new questionnaires demonstrating reasonable reliability (self-help confidence alpha = 0.78, mental health knowledge alpha = 0.59). There were indications of improvement in help-seeking intentions, the number of sources likely to seek help from, and mental health knowledge from pre- to post-intervention. A future trial of PEP with a sample of approximately 36 schools, researcher-led data collections, and help-seeking intentions or sources as a primary outcome appears to be feasible

    Studying Mental Health in Schools: A Participatory Action Research (PAR) Approach in Public Mental Health

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    Despite a rising prevalence of mental health difficulties in the young, existing prior to, but also exacerbated by the current COVID-19 pandemic, mental health needs in this population remain unmet even in economically wealthy countries. Increasingly, supportive school environments have been suggested as having a significant impact on young people's mental health. The idea of health- promoting schools, initiated by the World Health Organisation (WHO), highlights the ongoing need for both health education via the curriculum but also a school environment that is conducive to students' health and emotional well-being. Despite this promising public health measure, existing studies into mental health- related interventions delivered in schools have been found to have a small or no effect. One explanation for this is that previous studies did not sufficiently address or focus on the school environment, which may in itself pose barriers to acceptability and successful implementation of mental health interventions. This paper will highlight a novel methodological approach to public mental health research - Participatory Action Research (PAR). The PAR method is unique in enabling study participants to become co-researchers of their own experiences in a specific context. A growing body of educational PAR research suggests that this method can also generate collaborative and participative processes foundational to positive school culture and mental health outcomes. This paper will provide an overview of such outcomes, as well as outline methodological strengths and challenges common to the PAR approach in educational mental health settings

    School-based peer education interventions to improve health: a global systematic review of effectiveness.

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    INTRODUCTION: Peer education, whereby peers ('peer educators') teach their other peers ('peer learners') about aspects of health is an approach growing in popularity across school contexts, possibly due to adolescents preferring to seek help for health-related concerns from their peers rather than adults or professionals. Peer education interventions cover a wide range of health areas but their overall effectiveness remains unclear. This review aims to summarise the effectiveness of existing peer-led health interventions implemented in schools worldwide. METHODS: Five electronic databases were searched for eligible studies in October 2020. To be included, studies must have evaluated a school-based peer education intervention designed to address the health of students aged 11-18-years-old and include quantitative outcome data to examine effectiveness. The number of interventions were summarised and the impact on improved health knowledge and reductions in health problems or risk-taking behaviours were investigated for each health area separately, the Mixed Methods Appraisal Tool was used to assess quality. RESULTS: A total of 2125 studies were identified after the initial search and 73 articles were included in the review. The majority of papers evaluated interventions focused on sex education/HIV prevention (n = 23), promoting healthy lifestyles (n = 17) and alcohol, smoking and substance use (n = 16). Papers mainly reported peer learner outcomes (67/73, 91.8%), with only six papers (8.2%) focussing solely on peer educator outcomes and five papers (6.8%) examining both peer learner and peer educator outcomes. Of the 67 papers reporting peer learner outcomes, 35/67 (52.2%) showed evidence of effectiveness, 8/67 (11.9%) showed mixed findings and 24/67 (35.8%) found limited or no evidence of effectiveness. Of the 11 papers reporting peer educator outcomes, 4/11 (36.4%) showed evidence of effectiveness, 2/11 (18.2%) showed mixed findings and 5/11 (45.5%) showed limited or no evidence of effectiveness. Study quality varied greatly with many studies rated as poor quality, mainly due to unrepresentative samples and incomplete data. DISCUSSION: School-based peer education interventions are implemented worldwide and span a wide range of health areas. A number of interventions appear to demonstrate evidence for effectiveness, suggesting peer education may be a promising strategy for health improvement in schools. Improvement in health-related knowledge was most common with less evidence for positive health behaviour change. In order to quantitatively synthesise the evidence and make more confident conclusions, there is a need for more robust, high-quality evaluations of peer-led interventions using standardised health knowledge and behaviour measures

    Studying Mental Health in Schools: A Participatory Action Research (PAR) Approach in Public Mental Health

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    Despite a rising prevalence of mental health difficulties in the young, existing prior to, but also exacerbated by the current COVID-19 pandemic, mental health needs in this population remain unmet even in economically wealthy countries. Increasingly, supportive school environments have been suggested as having a significant impact on young people's mental health. The idea of health- promoting schools, initiated by the World Health Organisation (WHO), highlights the ongoing need for both health education via the curriculum but also a school environment that is conducive to students' health and emotional well-being. Despite this promising public health measure, existing studies into mental health- related interventions delivered in schools have been found to have a small or no effect. One explanation for this is that previous studies did not sufficiently address or focus on the school environment, which may in itself pose barriers to acceptability and successful implementation of mental health interventions. This paper will highlight a novel methodological approach to public mental health research - Participatory Action Research (PAR). The PAR method is unique in enabling study participants to become co-researchers of their own experiences in a specific context. A growing body of educational PAR research suggests that this method can also generate collaborative and participative processes foundational to positive school culture and mental health outcomes. This paper will provide an overview of such outcomes, as well as outline methodological strengths and challenges common to the PAR approach in educational mental health settings

    Far-infrared photometry of OJ 287 with the Herschel Space Observatory

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    Context: The blazar OJ 287 has shown a approximate to 12 year quasi-periodicity over more than a century, in addition to the common properties of violent variability in all frequency ranges. It is the strongest known candidate to have a binary singularity in its central engine.Aims: We aim to better understand the different emission components by searching for correlated variability in the flux over four decades of frequency measurements.Methods: We combined data at frequencies from the millimetric to the visible to characterise the multifrequency light curve in April and May 2010. This includes the only photometric observations of OJ 287 made with the Herschel Space Observatory: five epochs of data obtained over 33 days at 250, 350, and 500 mu m with Herschel-SPIRE.Results: Although we find that the variability at 37 GHz on timescales of a few weeks correlates with the visible to near-IR spectral energy distribution, there is a small degree of reddening in the continuum at lower flux levels that is revealed by the decreasing rate of decline in the light curve at lower frequencies. However, we see no clear evidence that a rapid flare detected in the light curve during our monitoring in the visible to near-IR light curve is seen either in the Herschel data or at 37 GHz, suggesting a low-frequency cut-off in the spectrum of such flares.Conclusions: We see only marginal evidence of variability in the observations with Herschel over a month, although this may be principally due to the poor sampling. The spectral energy distribution between 37 GHz and the visible can be characterised by two components of approximately constant spectral index: a visible to far-IR component of spectral index alpha = -0.95, and a far-IR to millimetric spectral index of alpha = -0.43. There is no evidence of an excess of emission that would be consistent with the 60 mu m dust bump found in many active galactic nuclei.</p

    Suppression of mutant Kirsten-RAS (KRASG12D)-driven pancreatic carcinogenesis by dual-specificity MAP kinase phosphatases 5 and 6

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    The cytoplasmic phosphatase DUSP6 and its nuclear counterpart DUSP5 are negative regulators of RAS/ERK signalling. Here we use deletion of either Dusp5 or Dusp6 to explore the roles of these phosphatases in a murine model of KRASG12D-driven pancreatic cancer. By 56-days, loss of either DUSP5 or DUSP6 causes a significant increase in KRASG12D-driven pancreatic hyperplasia. This is accompanied by increased pancreatic acinar to ductal metaplasia (ADM) and the development of pre-neoplastic pancreatic intraepithelial neoplasia (PanINs). In contrast, by 100-days, pancreatic hyperplasia is reversed with significant atrophy of pancreatic tissue and weight loss observed in animals lacking either DUSP5 or DUSP6. On further ageing, Dusp6−/− mice display accelerated development of metastatic pancreatic ductal adenocarcinoma (PDAC), while in Dusp5−/− animals, although PDAC development is increased this process is attenuated by atrophy of pancreatic acinar tissue and severe weight loss in some animals before cancer could progress. Our data suggest that despite a common target in the ERK MAP kinase, DUSP5 and DUSP6 play partially non-redundant roles in suppressing oncogenic KRASG12D signalling, thus retarding both tumour initiation and progression. Our data suggest that loss of either DUSP5 or DUSP6, as observed in certain human tumours, including the pancreas, could promote carcinogenesis
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