Partitioning de Bruijn Graphs into Fixed-Length Cycles for Robot Identification and Tracking

We propose a new camera-based method of robot identification, tracking and orientation estimation. The system utilises coloured lights mounted in a circle around each robot to create unique colour sequences that are observed by a camera. The number of robots that can be uniquely identified is limited by the number of colours available, $q$, the number of lights on each robot, $k$, and the number of consecutive lights the camera can see, $\ell$. For a given set of parameters, we would like to maximise the number of robots that we can use. We model this as a combinatorial problem and show that it is equivalent to finding the maximum number of disjoint $k$-cycles in the de Bruijn graph $\text{dB}(q,\ell)$. We provide several existence results that give the maximum number of cycles in $\text{dB}(q,\ell)$ in various cases. For example, we give an optimal solution when $k=q^{\ell-1}$. Another construction yields many cycles in larger de Bruijn graphs using cycles from smaller de Bruijn graphs: if $\text{dB}(q,\ell)$ can be partitioned into $k$-cycles, then $\text{dB}(q,\ell)$ can be partitioned into $tk$-cycles for any divisor $t$ of $k$. The methods used are based on finite field algebra and the combinatorics of words.Comment: 16 pages, 4 figures. Accepted for publication in Discrete Applied Mathematic

Sex is Not a Three-Letter Word: The Effect of Manipulating the Definition of Sex on the Future of Transgender Athletes

Title IX makes it unlawful for educational institutions receiving federal funding to discriminate “on the basis of sex.” But in the context of high school and college athletics, and specific to transgender athletes, what should the meaning of “sex” be? The Obama administration believed that “on the basis of sex” in Title IX includes “gender” in the meaning of “sex.” However, the Trump administration has proposed revoking that understanding, limiting the term “sex” to mean male or female, defined at birth. In the com- ing year, the Supreme Court may decide in R.G. & G.R. Harris Funeral Homes, Inc. v. EEOC whether sex discrimination laws apply to discrimination against transgender people. Its ruling will be instrumental as precedent for lower courts in deciding Title IX cases. This Note analyzes what the Supreme Court should consider in making its final judgment. This Note argues that the current interpretation of “sex” under Title IX should be maintained as defined by the Obama administration to mean that transgender high school and college athletes must be allowed to participate on the sports team that corresponds with their gender identity. This conclusion is supported by case law, as well as a close textual reading of Title IX, namely its use of the word “sex,” a term that can be interpreted broadly

Latent Health Status Trajectory Modelling In Patients With Symptomatic Peripheral Artery Disease

For patients with peripheral artery disease (PAD) and symptoms of intermittent claudication, treatment is geared towards maximizing health status and minimizing disease progression. We aimed to phenotype health status trajectories over the first 12 months of specialty care and examine factors associated with nonresponsiveness to treatment. Adults with new or worsening exertional leg symptoms presenting to vascular clinics in the United States, Australia, and Netherlands 2011-2015 were included. Patients with non-compressible ankle-brachial index, critical limb ischemia, barriers to consent, or lacking at least one follow-up interview were excluded. The Peripheral Artery Questionnaire (PAQ; range 0-100, higher = better) was used to capture disease-specific health status at baseline and during 3-, 6-, and 12-month follow-up visits. Latent trajectory modeling was used to delineate latent trajectory subgroups based on heterogeneity in longitudinal PAQ scores. Trajectories were classified as either Responsive or Nonresponsive by achievement of a mean ≥10-point improvement by the 12-month visit. Medical and psychosocial factors associated with a Nonresponsive trajectory were assessed by hierarchical multivariable logistic regression with a random effect for site. Of 2,917 eligible patients, 1,204 (41.3%) were included in the final cohort. The cohort was 62.5% male with a mean age of 67.5±9.4. Latent trajectory modelling revealed 5 subgroups: the High (n=401, 33.3%), Intermediate (n=400, 33.2%), Low (n=150, 12.5%), Sustained Response (n=98, 8.1%), and Transient Response (n=155, 12.9%) groups with +16.8, +59.4, +24.0, +8.6, and +7.6 score changes at 12-months, respectively. Following a Nonresponsive trajectory (Low or Transient Response) was associated with depressive symptom burden, however the effect did not remain significant after sequential adjustment for age, sex, race, country, baseline PAQ, and revascularization. Individuals with new or worsening PAD symptoms receiving specialty care exhibit diverse recovery trajectories. Roughly 1 in 4 experiences no meaningful improvement in health status at 12 months. Addressing psychosocial factors alongside medical comorbidities in an integrated care system may improve outcomes in PAD

Personality and temperamental features vs. quality of life of Polish seafarers

In Poland seafarers are a significantly large occupational group and their work is highly burdening andhazardous. The environmental, physical, chemical, biological and psychosocial factors have a great impacton their quality of work and life. This report examines their quality of life and the relationship betweenquality of life, personality and temperament was evaluated. A total of 300 Polish seafarers took part inthis study. Their average age is 44. Incorporated methods used were: WHOQOL-BREF, a survey for peopleworking at sea, questionnaires: NEO-FFI and PTS. The results have shown that their quality of life is quitehigh. Polish seafarers show neuroticism below average and high extraversion. They are open, agreeableand scrupulous. Their power of stimulation and inhibition processes is correct

Dynamics of stress as a predictor of health consequences in Polish drilling platform workers. Longitudinal study: part I

Background and aim: The subject of presented article is the evaluation of the relationship between the way of adaptation to work-related stress and chosen health indicators among drilling platform workers in Poland. The study procedure is a longitudinal research, including data analysis from 1993 to 2013.Materials and methods: 167 Polish platform male workers with an average age of 42 years have been examined. The studies include, according to the triangulation method, data from 3 sources: data concerningthe so-called ‘objective’ and ‘subjective’ stress, personality and temperamental examinations and data concerning health state.Results: Stress affects health negatively, the higher subjective and objective stress, the worse health indicators: higher body mass index, more declared health ailments and worse evaluation of personal health (r = –0.23). Stress also affects health via 2 indirect tracts: through the kind of stress adaptation (stress dynamics) (r = –0.43) and through coping — depositional stress coping style (r = 0.41).Conclusions: Stress adaptation (stress dynamics) and coping style included in the study in longer perspective show that those drilling platform workers, who declare the decrease of stress over the years, present worse health indicators than those, who declare variability in the ways of adaptation to stress

Quality of life at sea in Polish seafarer’s evaluation

Background: Work at sea is highly burdening, hazardous and stressful. Environmental, physical, and psychosociological factors have a great impact on the seafarer’s quality of life and work. The research is a part of a broader psychological project performed on people working at sea in Poland during a period of 2011–2014. Materials and methods: This report presents the self-evaluation of life quality conducted by a total of 1,700 Polish seafarers who took part in the study. The average age of the group was 45. Following methods were used: WHOQOL-BREF and the “Survey for people working at sea”. Results: Polish seafarers gave the highest rates to their social relationships (16.27), then the psychological functioning (15.62), and environment (15.51). The physical domain gave the lowest rates (14.63). Conclusions: The results have shown that quality of life of Polish seafarers is quite high