Permanent Weekend: Nature, Leisure, and Rural Gentrification by John Michels

Review of John Michels\u27 Permanent Weekend: Nature, Leisure, and Rural Gentrification

Edge-Transitive Bipartite Direct Products

In their recent paper ``Edge-transitive products, Hammack, Imrich, and Klavzar showed that the direct product of connected, non-bipartite graphs is edge-transitive if and only if both factors are edge-transitive, and at least one is arc-transitive. However, little is known when the product is bipartite. This thesis extends this result (in part) for the case of bipartite graphs using a new technique called stacking. For R-thin, connected, bipartite graphs A and B, we show that A x B is arc-transitive if and only if A and B are both arc-transitive. Further, we show A x B is edge-transitive only if at least one of A, B is also edge-transitive, and give evidence that strongly suggests that in fact both factors must be edge-transitive

Stories of Children, Youth, and Families’ Adaptation to Community Living in the First Year after Involvement with Children’s Residential Mental Health Programs

Twenty-two youth between the ages of 14 and 18 years old who were involved with residential programs from participating children’s mental health organizations in Southern Ontario, Canada during 2015 to 2017 participated in a study of adaptation to community living in the first year following program exit. Youth, parents, child welfare workers, and mental health workers took part in qualitative interviews up to three times during the study period. Interview comments were used to construct a narrative or “story” of the year following program exit that integrated multiple informants’ perspectives of how each youth was functioning within that timeframe. Stories for youth who returned home to live with their families (12 youth) were examined together to explore any common experiences or processes that described the post-discharge daily living of this group of youth and their families. Similarly, the stories of youth who resided in the care of the Children’s Aid Society following program exit (10 youth) were explored for commonalities that could offer insight into their community adaptation experiences. Study findings underscore the need for proactive and flexible aftercare programming to improve community living outcomes for youth leaving residential mental health programs

Asymptotic enumeration of incidence matrices

We discuss the problem of counting {\em incidence matrices}, i.e. zero-one matrices with no zero rows or columns. Using different approaches we give three different proofs for the leading asymptotics for the number of matrices with $n$ ones as $n\to\infty$. We also give refined results for the asymptotic number of $i\times j$ incidence matrices with $n$ ones.Comment: jpconf style files. Presented at the conference "Counting Complexity: An international workshop on statistical mechanics and combinatorics." In celebration of Prof. Tony Guttmann's 60th birthda

Origin of the hemispheric asymmetry of solar activity

The frequency spectrum of the hemispheric asymmetry of solar activity shows enhanced power for the period ranges around 8.5 years and between 30 and 50 years. This can be understood as the sum and beat periods of the superposition of two dynamo modes: a dipolar mode with a (magnetic) period of about 22 years and aquadrupolar mode with a period between 13 and 15 years. An updated Babcock-Leighton-type dynamo model with weak driving as indicated by stellar observations shows an excited dipole mode and a damped quadrupole mode in the correct range of periods. Random excitation of the quadrupole by stochastic fluctuations of the source term for the poloidal field leads to a time evolution of activity and asymmetry that is consistent with the observational results.Comment: Astronomy & Astrophysics, accepte

Are the strengths of solar cycles determined by converging flows towards the activity belts?

It is proposed that the observed near-surface inflows towards the active regions and sunspot zones provide a nonlinear feedback mechanism that limits the amplitude of a Babcock-Leighton-type solar dynamo and determines the variation of the cycle strength. This hypothesis is tested with surface flux transport simulations including converging latitudinal flows that depend on the surface distribution of magnetic flux. The inflows modulate the build-up of polar fields (represented by the axial dipole) by reducing the tilt angles of bipolar magnetic regions and by affecting the cross-equator transport of leading-polarity magnetic flux. With flux input derived from the observed record of sunspot groups, the simulations cover the period between 1874 and 1980 (corresponding to solar cycles 11 to 20). The inclusion of the inflows leads to a strong correlation of the simulated axial dipole strength during activity minimum with the observed amplitude of the subsequent cycle. This in agreement with empirical correlations and in line with what is expected from a Babcock-Leighton-type dynamo. The results provide evidence that the latitudinal inflows are a key ingredient in determining the amplitude of solar cycles.Comment: accepted in A&

Unspeakable Suffering; Eloquent Explanations: National Civil War Medicine Museum’s 26th Annual Conference

On Friday, October 12th, 2018, the National Civil War Medicine Museum kicked off its 26th annual conference and began its three-day event with a series of lectures on topics ranging from Confederate medical practice to cultural understandings of cowardice. A series of unique lectures given by a professionally diverse cast of presenters illuminated the often-peripheral field of Civil War Medicine. [excerpt