3,437 research outputs found
A -Queens Problem. II. The Square Board
We apply to the chessboard the counting theory from Part I for
nonattacking placements of chess pieces with unbounded straight-line moves,
such as the queen. Part I showed that the number of ways to place identical
nonattacking pieces is given by a quasipolynomial function of of degree
, whose coefficients are (essentially) polynomials in that depend
cyclically on .
Here we study the periods of the quasipolynomial and its coefficients, which
are bounded by functions, not well understood, of the piece's move directions,
and we develop exact formulas for the very highest coefficients. The
coefficients of the three highest powers of do not vary with . On the
other hand, we present simple pieces for which the fourth coefficient varies
periodically. We develop detailed properties of counting quasipolynomials that
will be applied in sequels to partial queens, whose moves are subsets of those
of the queen, and the nightrider, whose moves are extended knight's moves.
We conclude with the first, though strange, formula for the classical
-Queens Problem and with several conjectures and open problems.Comment: 23 pp., 1 figure, submitted. This = second half of 1303.1879v1 with
great improvements. V2 has a new proposition, better definitions, and
corrected conjectures. V3 has results et al. renumbered to correspond with
published version, and expands dictionary's cryptic abbreviation
NiO Exchange Bias Layers Grown by Direct Ion Beam Sputtering of a Nickel Oxide Target
A new process for fabricating NiO exchange bias layers has been developed.
The process involves the direct ion beam sputtering (IBS) of a NiO target. The
process is simpler than other deposition techniques for producing NiO buffer
layers, and facilitates the deposition of an entire spin-valve layered
structure using IBS without breaking vacuum. The layer thickness and
temperature dependence of the exchange field for NiO/NiFe films produced using
IBS are presented and are similar to those reported for similar films deposited
using reactive magnetron sputtering. The magnetic properties of highly textured
exchange couples deposited on single crystal substrates are compared to those
of simultaneously deposited polycrystalline films, and both show comparable
exchange fields. These results are compared to current theories describing the
exchange coupling at the NiO/NiFe interface.Comment: 9 pages, Latex 2.09, 3 postscript figures. You can also this
manuscript at http://www.wsrcc.com/alison/fixed-nio/manuscript.html To be
published in _IEEE Trans. Magn._, Nov. 199
Traditional patterns and modern dilemmas: designing locally appropriate health interventions
This paper describes the environmental, social, and economic conditions that contribute to the high rates of childhood mortality, morbidity, and malnutrition in Mbita Division, South Nyanza District. This information is used to recommend intervention programmes such as the introduction of improved weaning foods using local resources, improved sanitation and health care delivery, and implementation of community based health care. These interventions are intended specifically to address identified problems in a feasible and culturally appropriate manner. Ultimately, the solutions to community health problems are not technical, but lie with optimal use of human resources
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An information-processing analysis of the effects of communication modality on opinion change.
Communicating health decisions: an analysis of messages posted to online prostate cancer forums
Background 
Experiential websites such as message forums and blogs allow Prostate Cancer (PCa) patients to communicate their health decisions to peers. The issues surrounding this form of indirect involvement in public health are little understood.
Objective 
This paper explores the types of decision-making processes that people are exposed to on PCa online message boards. The kinds of treatment choices patients are making and the reports of their decision-making processes to peers through an online environment are examined in the context of the Heuristic Systematic Model.
Method 
Messages about treatment decision making were collected from four PCa websites. In total, 137 messages were selected from blogs and online forums and their decision-making processes coded.
Results 
Men looking online for information about treatment options for PCa are exposed to a range of decision-making processes. Just under half (49.6%) of the messages reported non-systematic decision processes, with deferral to the doctor and proof of cancer removal being the most common. For systematic processing (36.5%), messages most commonly considered treatment outcomes and side-effects. Processes did not vary between the blogs and online forums.
Discussion and conclusion 
Compared to previous studies far fewer messages reported non-systematic decision processes and only a small number of messages reflected lay beliefs or misbeliefs about PCa treatment. Implications for men and their clinicians of seeking health information online are discussed
Application of Fractals and Kinetic Equation in Modelling Cluster and Ultrafine Particle Size Distributions
We briefly describe a model which seems to be applicable to a variety of coalescence growth systems. Spanning cluster growth, particle growth and hillock formation in thin metal films, this model is based on the Smoluchowski kinetic equations and fractals. We describe how this model has been able to suggest the effect of translational to internal energy conversion in coalescing systems in determining the shape of particle size distributions. We also suggest how this model can be employed to account for the behavior of hillocks in supersaturated alloy films under thermal annealing conditions
Scaling and the Smoluchowski Equations
The Smoluchowski equations, which describe coalescence growth, take into account combination reactions between a j-mer and a k-mer to form a (j+k)-mer, but not breakup of larger clusters to smaller ones. All combination reactions are assumed to be second order, with rate constants K jk. The K jk are said to scale if K λj,γk =λ μγ μK jk for j ≤ k. It can then be shown that, for large k, the number density or population of k-mers is given by Ak ae -bk, where A is a normalization constant (a function of a, b, and time), a=-(μ+ ν), and b μ+ν-1 depends linearly on time. We prove this in a simple, transparent manner. We also discuss the origin of odd-even population oscillations for small k. A common scaling arises from the ballistic model, which assumes that the velocity of a k-mer is proportional to 1/ √m k (Maxwell distribution), i.e., thermal equilibrium. This does not hold for the nascent distribution of clusters produced from monomers by reactive collisions. By direct calculation, invoking conservation of momentum in collisions, we show that, for this distribution, velocities are proportional to m k -0-.577. This leads to μ+ν=0.090, intermediate between the ballistic (0.167) and diffusive (0.000) results. These results are discussed in light of the existence of systems in the experimental literature which apparently correspond to very negative values of μ+ν
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