A direct approach to co-universal algebras associated to directed graphs

We prove directly that if E is a directed graph in which every cycle has an entrance, then there exists a C*-algebra which is co-universal for Toeplitz-Cuntz-Krieger E-families. In particular, our proof does not invoke ideal-structure theory for graph algebras, nor does it involve use of the gauge action or its fixed point algebra.Comment: 9 pages; V2: the definition of a Toeplitz-Cuntz-Krieger $E$-family has been correcte

Willpower and Ego-Depletion: How I Do What I Don’t Want to Do, and Why It’s Not (Completely) My Fault When I Don’t

Experimental studies on willpower confirm the Strength Model of Self-Control, which claims that willpower depends on limited physiological resources. Exercising willpower depletes these resources, which impairs further exercises of willpower. This phenomenon is called “ego-depletion.” As a result, depleting these resources impairs further exercises of executive control. My thesis argues that this phenomenon has two important philosophical consequences: First, ego-depletion provides evidence against the Humean approach to motivation, according to which people always act according to their strongest desires. Second, people suffering from ego-depletion are not fully responsible for failures of self-control

Drivers and constraints to environmental sustainability in UK-based biobanking: balancing resource efficiency and future value

Background: Biobanks are a key aspect of healthcare research; they enable access to a wide range of heterogenous samples and data, as well as saving individual researchers time and funds on the collection, storage and/or curation of such resources. However, biobanks are also associated with impacts associated with a depletion of natural resources (energy, water etc.) production of toxic chemicals during manufacturing of laboratory equipment, and effects on biodiversity. We wanted to better understand the biobanking sector in the UK as a first step to assessing the environmental impacts of UK biobanking. // Methods: We explored the sample storage infrastructure and environmental sustainability practices at a number of UK biobanks through a mixed methods quantitative and qualitative approach, including information gathering on an online platform, and eight in-depth interviews. // Results: Environmental sustainability was deprioritised behind biobanks’ financial sustainability practices. Nevertheless, both often aligned in practice. However, there was a tendency towards underutilisation of stored samples, the avoidance of centralisation, and providing accessibility to biosamples, and this conflicted with valuing sustainability goals. This related to notions of individualised and competitive biobanking culture. Furthermore, the study raised how value attachments to biosamples overshadows needs for both financial and environmental sustainability concerns. // Conclusions: We need to move away from individualised and competitive biobanking cultures towards a realisation that the health of the publics and patients should be first and foremost. We need to ensure the use of biosamples, ahead of their storage (‘smart attachments’), align with environmental sustainability goals and participants’ donation wishes for biosample use

von Neuman algebras of strongly connected higher-rank graphs

We investigate the factor types of the extremal KMS states for the preferred dynamics on the Toeplitz algebra and the Cuntz--Krieger algebra of a strongly connected finite $k$-graph. For inverse temperatures above 1, all of the extremal KMS states are of type I$_\infty$. At inverse temperature 1, there is a dichotomy: if the $k$-graph is a simple $k$-dimensional cycle, we obtain a finite type I factor; otherwise we obtain a type III factor, whose Connes invariant we compute in terms of the spectral radii of the coordinate matrices and the degrees of cycles in the graph.Comment: 16 pages; 1 picture prepared using TikZ. Version 2: this version to appear in Math. An

The internal validity of the school-level comparative interrupted time series design: evidence from four new within-study comparisons

Comparative interrupted time series (CITS) designs evaluate impact by modeling the relative deviation from trends among a treatment and comparison group after an intervention. The broad applicability of the design means it is widely used in education research. Like all non-experimental evaluation methods however, the internal validity of a given CITS evaluation depends on assumptions that cannot be directly verified. We provide an empirical test of the internal validity of CITS by conducting four within-study comparisons of school-level interventions previously evaluated using randomized controlled trials. Our estimate of bias across these four studies is 0.03 school-level (or 0.01 pupil-level) standard deviations. The results suggest well-conducted CITS evaluations of similar school-level education interventions are likely to display limited bias

On some fundamental results about higher-rank graphs and their C*-algebras

Results of Fowler and Sims show that every k-graph is completely determined by its k-coloured skeleton and collection of commuting squares. Here we give an explicit description of the k-graph associated to a given skeleton and collection of squares and show that two k-graphs are isomorphic if and only if there is an isomorphism of their skeletons which preserves commuting squares. We use this to prove directly that each k-graph {\Lambda} is isomorphic to the quotient of the path category of its skeleton by the equivalence relation determined by the commuting squares, and show that this extends to a homeomorphism of infinite-path spaces when the k-graph is row finite with no sources. We conclude with a short direct proof of the characterisation, originally due to Robertson and Sims, of simplicity of the C*-algebra of a row-finite k-graph with no sources.Comment: 21 pages, two pictures prepared using TiK

Physical Activity, Park, Nature Trail Usage among Students, Faculty and Staff at a Mid-sized University

Physical activity (PA) is a vital component of a healthy lifestyle. There is strong evidence demonstrating an association between PA and reduced risk of many chronic diseases, increasing in prevalence and incidence in the United States. PURPOSE: The purpose of the study was to determine the PA levels of the students, faculty, and staff members of a mid-sized state university and how usage of a nature center and community park facilitated PA. METHODS: An observational, cross-sectional survey design was used to complete the study objectives. The 20-minute survey was distributed online using Survey Monkey to all faculty, staff and students at the host university. It consisted of basic demographic questions, questions concerning respondents’ physical activity behaviors and their use of two community parks to engage in physical activity. The two park spaces included in the survey, Bay Area Park (BAP) and Armand Bayou Nature Center (ABNC), are located approximately 3.5 Km from the university. Survey respondents were incentivized by being entered into a raffle to win a small gift card and students could receive course credit for completing the survey. RESULTS: The survey was completed by 952 students, 94 faculty, and 250 staff members. Students reported the least PA, with an average of 2.8 PA days per week, 26.9% reporting no PA days per week, and only 5.3% reporting daily PA. Staff reported 3.0 average PA days per week, 20.2% reported no PA days per week, and 5.9% reported daily PA. Faculty reported 3.4 average PA days per week, 21.4% reported no PA days per week, and 14.3% reported daily PA. Participants less than 20y reported the least amount of inactivity (15.7%); 9.8% reported daily PA and on average exercised 3.3 days per week. Participants 50-60y reported the highest amount of inactivity (28.6%) and \u3e60y reported the lowest average number PA days per week (2.7 days). Students, faculty, and staff report not using parks (including BAP and ABNC) as a main place for PA; 69.5% report not visiting a park in the last week, 59% have not visited BAP in the last 3 months and 84% have not visited ABNC in the past 3 months. CONCLUSIONS: Students, faculty, and staff surveyed are not meeting the recommended daily PA. Neighborhood outdoor space is the main space used for PA (38.1%). The majority of students, faculty and staff surveyed had not visited any parks in the week leading up to this survey and most have not visited the parks utilized in this survey during the past 3-months. Further research interventions is necessary to determine if awareness of parks and nature trails facilitate increased physical activity

High-Speed Vessel Noises in West Hong Kong Waters and Their Contributions Relative to Indo-Pacific Humpback Dolphins ( Sousa chinensis

The waters of West Hong Kong are home to a population of Indo-Pacific humpback dolphins (Sousa chinensis) that use a variety of sounds to communicate. This area is also dominated by intense vessel traffic that is believed to be behaviorally and acoustically disruptive to dolphins. While behavioral changes have been documented, acoustic disturbance has yet to be shown. We compared the relative sound contributions of various high-speed vessels to nearby ambient noise and dolphin social sounds. Ambient noise levels were also compared between areas of high and low traffic. We found large differences in sound pressure levels between high traffic and no traffic areas, suggesting that vessels are the main contributors to these discrepancies. Vessel sounds were well within the audible range of dolphins, with sounds from 315–45,000 Hz. Additionally, vessel sounds at distances ≥100 m exceeded those of dolphin sounds at closer distances. Our results reaffirm earlier studies that vessels have large sound contributions to dolphin habitats, and we suspect that they may be inducing masking effects of dolphin sounds at close distances. Further research on dolphin behavior and acoustics in relation to vessels is needed to clarify impacts

The correlation between inflammatory biomarkers and polygenic risk score in Alzheimer's Disease

Plasma biomarkers to aid the early diagnosis of Alzheimer’s disease (AD) or to monitor disease progression have long been sought and continue to be widely studied. Biomarkers that correlate with AD polygenic risk score, a measure of the polygenic architecture of the disease and highly predictive of AD status, would be excellent candidates. Therefore, we undertook a preliminary study to assess the association of plasma inflammatory biomarkers with an overall AD polygenic risk score as well as with an inflammation-specific AD polygenic risk score in a sample set of 93 AD cases. We measured five complement biomarkers [complement receptor 1 (CR1), clusterin, complement component 9 (C9), C1 inhibitor (C1inh), terminal complement complex (TCC)] and the benchmark inflammatory marker C-reactive protein (CRP). Plasma clusterin level showed an association with overall AD polygenic risk score, while clusterin, C1inh, and CRP levels each displayed some association with the inflammatory-specific AD polygenic risk score. The results suggest that elevated plasma levels of inflammatory biomarkers, including complement proteins, associate with polygenic risk scores in AD, further strengthening the link between genetic and biomarker disease predictors and indicating a potential role for these markers in disease prediction and patient stratification in AD