46,049 research outputs found
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
Penumbral structure and outflows in simulated sunspots
Sunspots are concentrations of magnetic field on the visible solar surface
that strongly affect the convective energy transport in their interior and
surroundings. The filamentary outer regions (penumbrae) of sunspots show
systematic radial outward flows along channels of nearly horizontal magnetic
field. These flows were discovered 100 years ago and are present in all fully
developed sunspots. Using a comprehensive numerical simulation of a sunspot
pair, we show that penumbral structures with such outflows form when the
average magnetic field inclination to the vertical exceeds about 45 degrees.
The systematic outflows are a component of the convective flows that provide
the upward energy transport and result from anisotropy introduced by the
presence of the inclined magnetic field.Comment: 19 pages, 8 figures, main Science article + supporting online
material combined into one fil
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
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&
Returns to Education between the Self-employed and Employed Sectors: Evidence from Malaysia
Investment in human capital in terms of returns to education is considered a crucial factor that contributes to the remarkable economic growth especially in the rapidly developing countries. Since poverty and education are closely related, this paper attempts to examine whether returns to education differ between the self-employed and employed sectors in the rural Malay area in Rantau, Malaysia. Using the adjusted Mincerian Earnings function and the dummy variables approach, the empirical finding shows that returns to education do not differ between the self-employed and employed sectors in the rural Malay society. Thus, it can be deduced that there is no significant difference between the self-employed and employed sectors in those two sectors. Interestingly, it also reveals that private rates of return (ROR) increase by the level of schooling and they are the highest at the Secondary level. Finally, appropriate strategies are further suggested to alleviate poverty in the case study area.
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