Sensitivities of the absorptive partitioning model of secondary organic aerosol formation to the inclusion of water

The predicted distribution of semi-volatile organic components between the gaseous and condensed phase as a function of ambient relative humidity and the specific form of the partitioning model used has been investigated. A mole fraction based model, modified so as not to use molar mass in the calculation, was found to predict identical RH dependence of component partitioning to that predicted by the conventional mass-based partitioning model which uses a molar mass averaged according to the number of moles in the condensed phase. A recently reported third version of the partitioning model using individual component molar masses was shown to give significantly different results to the other two models. Further sensitivities to an assumed pre-existing particulate loading and to parameterised organic component non-ideality are explored and shown to contribute significantly to the variation in predicted secondary organic particulate loading

Survey to Inform the Development of an Online Support System for Higher Education Students - Higher Education and Online Support

An increasing number of higher education students face mental health difficulties, but the universities’ student support services (SSS) struggle to meet demand with limited resources. Web-based alternatives hold promise as a novel medium through which students could access support. Online interventions appear to be effective and may therefore provide a cost-effective alternative, relieving some of the burden on struggling SSS. This paper presents results from an explorative survey of 61 students questioned about their opinion of online support systems. The majority of students indicated that they would use such a system and that it should be interactive and personalized, focusing on time and money management, relaxation exercises, and building social skills. Future directions towards the development of such a system are discussed

Online intervention, ‘MePlusMe’, supporting mood, wellbeing, study skills, and everyday functioning in students in higher education: a protocol for a feasibility study

Background: Psychological and study skill difficulties faced by students in higher education can lead to poor academic performance, sub-optimal mental health, reduced study satisfaction, and drop out from study. At the same time, higher education institutions’ support services are costly, oversubscribed, and struggle to meet demand whilst facing budget reductions. The purpose of the proposed study is to evaluate the acceptability of a new online intervention, MePlusMe, aimed at students in higher education facing mild to moderate psychological and/or study skill difficulties. The study will also assess the feasibility of proposed recruitment and outcome assessment protocols for a future trial of effectiveness. The system supports self-management strategies alongside ongoing monitoring facilitated by a messaging service, as well as featuring a built-in community of student users. It is based on current clinical guidelines for the management of common mental health problems, together with best practice from the educational field. Methods/design: Two hundred and forty two students will be recruited to a within-subjects, repeated measures study conducted over 8 weeks. Self-report measures of depression and anxiety symptoms, mental wellbeing, academic self-efficacy, and everyday functioning will be collected at baseline, and then at 2, 4, and 8 weeks. During this period, students will have access to the intervention system. UK higher education institutions Bournemouth University and University of Warwick will participate in the study. Data on student satisfaction and engagement will also be collected. Study findings will help to determine the most appropriate primary outcome and the required sample size for a future trial. Discussion: This study will evaluate the acceptability of an online intervention system for students facing psychological and/or study skill difficulties and will test recruitment procedures and outcome measures for a future trial of effectiveness. The system is designed to be implemented as a stand-alone service or a service complementary to student support services, which is accessible to the majority of students and effective in improving student experience at higher education institutions

Results from the NASA Spacecraft Fault Management Workshop: Cost Drivers for Deep Space Missions

Fault Management, the detection of and response to in-flight anomalies, is a critical aspect of deep-space missions. Fault management capabilities are commonly distributed across flight and ground subsystems, impacting hardware, software, and mission operations designs. The National Aeronautics and Space Administration (NASA) Discovery & New Frontiers (D&NF) Program Office at Marshall Space Flight Center (MSFC) recently studied cost overruns and schedule delays for five missions. The goal was to identify the underlying causes for the overruns and delays, and to develop practical mitigations to assist the D&NF projects in identifying potential risks and controlling the associated impacts to proposed mission costs and schedules. The study found that four out of the five missions studied had significant overruns due to underestimating the complexity and support requirements for fault management. As a result of this and other recent experiences, the NASA Science Mission Directorate (SMD) Planetary Science Division (PSD) commissioned a workshop to bring together invited participants across government, industry, and academia to assess the state of the art in fault management practice and research, identify current and potential issues, and make recommendations for addressing these issues. The workshop was held in New Orleans in April of 2008. The workshop concluded that fault management is not being limited by technology, but rather by a lack of emphasis and discipline in both the engineering and programmatic dimensions. Some of the areas cited in the findings include different, conflicting, and changing institutional goals and risk postures; unclear ownership of end-to-end fault management engineering; inadequate understanding of the impact of mission-level requirements on fault management complexity; and practices, processes, and tools that have not kept pace with the increasing complexity of mission requirements and spacecraft systems. This paper summarizes the findings and recommendations from that workshop, particularly as fault management development issues affect operations and the development of operations capabilities

Variation Across Mitochondrial Gene Trees Provides Evidence For Systematic Error: How Much Gene Tree Variation Is Biological?

The use of large genomic data sets in phylogenetics has highlighted extensive topological variation across genes. Much of this discordance is assumed to result from biological processes. However, variation among gene trees can also be a consequence of systematic error driven by poor model fit, and the relative importance of biological vs. methodological factors in explaining gene tree variation is a major unresolved question. Using mitochondrial genomes to control for biological causes of gene tree variation, we estimate the extent of gene tree discordance driven by systematic error and employ posterior prediction to highlight the role of model fit in producing this discordance. We find that the amount of discordance among mitochondrial gene trees is similar to the amount of discordance found in other studies that assume only biological causes of variation. This similarity suggests that the role of systematic error in generating gene tree variation is underappreciated and critical evaluation of fit between assumed models and the data used for inference is important for the resolution of unresolved phylogenetic questions

Exploring the feasibility and acceptability of the contents, design, and functionalities of an online intervention promoting mental health, wellbeing, and study skills in Higher Education students

Background: Substantial numbers of students in Higher Education (HE) are reporting mental health difficulties, such as mild to moderate symptoms of depression and anxiety. Coupled with academic skills challenges, these difficulties can lead to decreased academic performance, low levels of study satisfaction, and eventually drop out. Student support services are facing budget cuts and can only attend to limited numbers of students, usually the ones who present with more severe mental health problems. Moreover, face-to-face contact may not appeal to those students who feel embarrassed by their problems or are afraid of being stigmatised. To address this important problem, an online psychological wellbeing and study skills support system called MePlusMe, has been developed to provide personalised support to its users. In the present study we investigated the feasibility and acceptability of the contents, design, and functionalities of the system. Methods: An offline version of the system was introduced to 13 postgraduate and undergraduate students (mean age = 31.3 years, SD = 10.25 years; 4 males) in a UK HE Institution, who presented with mild or moderate mental health difficulties. The participants evaluated the design of the system, its functionalities, and contents at Baseline and at Weeks 2, 4, and 8. Results: Participants found the system easy to use, professional, and efficient and its contents non-judgemental and informative. Participants stated that engaging with and practicing the techniques targeted at mental health difficulties led to improvements in positive thinking and self-confidence, while the study skills techniques were practical. Suggestions for further improvement included the development of an app and an option for direct engagement with professionals. Conclusions: The findings confirmed the acceptability of the contents, design and functionalities of the system, while providing useful information to inform its further development. Next steps include a feasibility study, which will test and quantify the effects on everyday functioning, mood, mental wellbeing, and academic self-efficacy after using the system, and subsequently a randomized controlled trial, which will evaluate its effectiveness

The UPBEAT nurse-delivered personalized care intervention for people with coronary heart disease who report current chest pain and depression: a randomised controlled pilot study

Background: Depression is common in people with coronary heart disease (CHD) and associated with worse outcome. This study explored the acceptability and feasibility of procedures for a trial and for an intervention, including its potential costs, to inform a definitive randomized controlled trial (RCT) of a nurse-led personalised care intervention for primary care CHD patients with current chest pain and probable depression. Methods: Multi-centre, outcome assessor-blinded, randomized parallel group study. CHD patients reporting chest pain and scoring 8 or more on the HADS were randomized to personalized care (PC) or treatment as usual (TAU) for 6 months and followed for 1 year. Primary outcome was acceptability and feasibility of procedures; secondary outcomes included mood, chest pain, functional status, well being and psychological process variables. Result: 1001 people from 17 General Practice CHD registers in South London consented to be contacted; out of 126 who were potentially eligible, 81 (35% female, mean age = 65 SD11 years) were randomized. PC participants (n = 41) identified wide ranging problems to work on with nurse-case managers. Good acceptability and feasibility was indicated by low attrition (9%), high engagement and minimal nurse time used (mean/SD = 78/19 mins assessment, 125/91 mins telephone follow up). Both groups improved on all outcomes. The largest between group difference was in the proportion no longer reporting chest pain (PC 37% vs TAU 18%; mixed effects model OR 2.21 95% CI 0.69, 7.03). Some evidence was seen that self efficacy (mean scale increase of 2.5 vs 0.9) and illness perceptions (mean scale increase of 7.8 vs 2.5) had improved in PC vs TAU participants at 1 year. PC appeared to be more cost effective up to a QALY threshold of approximately £3,000. Conclusions: Trial and intervention procedures appeared to be feasible and acceptable. PC allowed patients to work on unaddressed problems and appears cheaper than TAU

The effect of photochemical ageing and initial precursor concentration on the composition and hygroscopic properties of β-caryophyllene secondary organic aerosol

The effect of photochemical ageing and initial precursor concentration on the composition and hygroscopic properties of secondary organic aerosol (SOA) formed during the chamber photo-oxidation of β-caryophyllene/NO_x mixtures were investigated. Nucleation of β-caryophyllene SOA particles occurred almost immediately after oxidation was initiated and led to the formation of fresh SOA with a relatively simpler composition than has been reported for monoterpenes. The SOA yield values ranged from 9.5–26.7% and 30.4–44.5% using a differential mobility particle sizer (DMPS) and an aerosol mass spectrometer (AMS) mass based measurements, respectively. A total of 20 compounds were identified in the SOA by LC-MS/MS, with the most abundant compounds identified as β-caryophyllonic acid and β-caryophyllinic acid/β-nocaryophyllonic acid. The O:C and H:C elemental ratios of products identified in the condensed phase ranged from 0.20 to 1.00 and 1.00 to 2.00, with average values of 0.39 and 1.58, respectively. The increase in the O:C ratio was associated with a decrease in the saturation concentration of the identified compounds. The compounds identified in the lower initial concentration experiments were more oxidised compared to those that were found to be more abundant in the higher initial concentration experiments with average O:C ratios of 0.51 and 0.27, respectively. Photochemical ageing led to a more complex SOA composition with a larger contribution coming from lower molar mass, higher generation products, where both double bonds had been oxidised. This effect was more evident in the experiments conducted using the lower initial precursor concentration; a finding confirmed by the temporal behaviour of key organic mass fragment measured by an Aerosol Mass Spectrometer. Although the composition changed with both initial precursor concentration and ageing, this had no significant measurable effect on the hygroscopic properties of the SOA formed. The latter finding might have been influenced by the difference in pre-treatment of the semivolatile-containing particles prior to their measurements