Optimality program in segment and string graphs

Planar graphs are known to allow subexponential algorithms running in time $2^{O(\sqrt n)}$ or $2^{O(\sqrt n \log n)}$ for most of the paradigmatic problems, while the brute-force time $2^{\Theta(n)}$ is very likely to be asymptotically best on general graphs. Intrigued by an algorithm packing curves in $2^{O(n^{2/3}\log n)}$ by Fox and Pach [SODA'11], we investigate which problems have subexponential algorithms on the intersection graphs of curves (string graphs) or segments (segment intersection graphs) and which problems have no such algorithms under the ETH (Exponential Time Hypothesis). Among our results, we show that, quite surprisingly, 3-Coloring can also be solved in time $2^{O(n^{2/3}\log^{O(1)}n)}$ on string graphs while an algorithm running in time $2^{o(n)}$ for 4-Coloring even on axis-parallel segments (of unbounded length) would disprove the ETH. For 4-Coloring of unit segments, we show a weaker ETH lower bound of $2^{o(n^{2/3})}$ which exploits the celebrated Erd\H{o}s-Szekeres theorem. The subexponential running time also carries over to Min Feedback Vertex Set but not to Min Dominating Set and Min Independent Dominating Set.Comment: 19 pages, 15 figure

Research and Engineering Division semiannual report. KK process development and technology, November 1, 1974--April 30, 1975

Research and engineering activities with the goal of improving the performance of the plutonium processing and waste management programs being operated by the Atlantic Richfield Hanford Company are reported. (auth

Minimal Mindfulness for Maximum Impact: Mandalas, Positivity, Self-Compassion, and Gratitude in the Higher Education Classroom

Numerous mindfulness-based interventions have demonstrated significant increases in users’ overall physical and emotional well-being. Often, however, graduate-level instructors believe it would be too time-consuming to incorporate these worthwhile self-care strategies into their curriculum. The aim of this study was to evaluate whether participating in a day of mindfulness-based activities could increase overall mindfulness in graduate students. Intervention activities were focused on creating a safe and focused space, as well as instilling self-compassion, positivity, and gratitude. Twelve female graduate students completed short activities utilizing mandalas, prompts for self-compassion and positivity, and a forgiveness practice. Paired-samples t-tests showed the intervention significantly increased overall mindfulness in these students. This suggests the benefit of using mindfulness-based interventions in higher education

Cryogenic silicification of microorganisms in hydrothermal fluids

Silica-rich hydrothermal fluids that experience freezing temperatures precipitate cryogenic opal-A (COA) within ice-bound brine channels. We investigated cryogenic silicification as a novel preservation pathway for chemo- and photo-lithotrophic Bacteria and Archaea. We find that the co-partitioning of microbial cells and silica into brine channels causes microorganisms to become fossilised in COA. Rod- and coccoidal-form Bacteria and Archaea produce numerous cell casts on COA particle surfaces, while Chloroflexus filaments are preserved inside particle interiors. COA particles precipitated from natural Icelandic hot spring fluids possess similar biomorphic casts, including those containing intact microbial cells. Biomolecules and inorganic metabolic products are also captured by COA precipitation, and are detectable with a combination of visible - shortwave infrared reflectance, FTIR, and Raman spectroscopy. We identify cryogenic silicification as a newly described mechanism by which microbial biosignatures can be preserved within silica-rich hydrothermal environments. This work has implications for the interpretation of biosignatures in relic hydrothermal settings, and for life-detection on Mars and Enceladus, where opaline silica indicative of hydrothermal activity has been detected, and freezing surface conditions predominate

Student anti-bullying and harassment policies at UK universities

This article provides the first analysis of all available UK university anti-bullying policies, summarising, comparing, and contrasting the content of policies acquired from university websites. The importance of anti-bullying policies is known from policy research in schools and workplaces but has previously not been investigated in Higher Education. A new coding framework and guidelines were developed to enable our analysis, and universities were given a score. Scores indicated variation between policies, suggesting some students may have inadequate support when consulting their university policy. The findings indicate that all universities should create and implement an anti-bullying policy. Students could be involved in the development of interventions or policies, as co-created initiatives may be more influential. University policy must be up-to-date, inclusive, comprehensive yet concise, and it must be publicised. We propose that our novel coding framework could be of use to policy makers and researchers investigating bullying policy within higher education

A systematic review of the organizational, environmental, professional and child and family factors influencing the timing of admission to hospital for children with serious infectious illness

Abstract Background Infection, particularly in the first 5 years of life, is a major cause of childhood deaths globally, many deaths from infections such as pneumonia and meningococcal disease are avoidable, if treated in time. Some factors that contribute to morbidity and mortality can be modified. These include organisational and environmental factors as well as those related to the child, family or professional. Objective Examine what organizational and environmental factors and individual child, family and professional factors affect timing of admission to hospital for children with a serious infectious illness. Design Systematic review. Data sources Key search terms were identified and used to search CINAHL Plus, Medline, ASSIA, Web of Science, The Cochrane Library, Joanna Briggs Institute Database of Systematic Review. Study appraisal methods Primary research (e.g. quantitative, qualitative and mixed methods studies) and literature reviews (e.g., systematic, scoping and narrative) were included if participants included or were restricted to children under 5 years of age with serious infectious illnesses, included parents and/or first contact health care professionals in primary care, urgent and emergency care and where the research had been conducted in OECD high income countries. The Mixed Methods Appraisal Tool was used to review the methodological quality of the studies. Main findings Thirty-six papers were selected for full text review; 12 studies fitted the inclusion criteria. Factors influencing the timing of admission to hospital included the variability in children’s illness trajectories and pathways to hospital, parental recognition of symptoms and clinicians non-recognition of illness severity, parental help-seeking behaviour and clinician responses, access to services, use and non-use of ‘gut feeling’ by clinicians, and sub-optimal management within primary, secondary and tertiary services. Conclusions The pathways taken by children with a serious infectious illness to hospital are complex and influenced by a variety of potentially modifiable individual, organisational, environmental and contextual factors. Supportive, accessible, respectful services that provide continuity, clear communication, advice and safety-netting are important as is improved training for clinicians and a mandate to attend to ‘gut feeling’. Implications Relatively simple interventions such as improved communication have the potential to improve the quality of care and reduce morbidity and mortality in children with a serious infectious illness

Exploring the Baccalaureate Origin of Domestic Ph.D. Students in Computing Fields

Increasing the number of US students entering graduate school and receiving a Ph.D. in computer science is a goal as well as a challenge for many US Ph.D. granting institutions. Although the total computer science Ph.D. production in the U.S. has doubled between 2000 and 2010 (Figure 1), the fraction of domestic students receiving a Ph.D. from U.S. graduate programs has been below 50% since 2003 (Figure 2). The goal of the Pipeline Project of CRA-E (PiPE) is to better understand the pipeline of US citizens and Permanent Residents (henceforth termed domestic students ) who apply, matriculate, and graduate from doctoral programs in computer science. This article is the first of two articles from CRA-E examining this issue. This article provides an initial examination of the baccalaureate origins of domestic students who have matriculated to Ph.D. programs in computer science. We hope that trends and patterns in these data can be useful both in recruiting and, ultimately, in improving the quality and quantity of the domestic Ph.D. pipeline