307 research outputs found
Can Forest Management Strategies Sustain The Development Needs Of The Little Red River Cree First Nation?
In this study, we explore whether projected socio-economic needs of the Little Red River Cree Nation (LRRCN) can be met using the natural resources to which they have access. To answer this question, we employ a dynamic optimization model to assess the capacity of the available forest base to provide for anticipated future needs of the LRRCN. Results for alternative management strategies indicate that decision-makers face significant tradeoffs in deciding an appropriate management strategy for the forestlands they control.boreal forest, First Nations, forest management, sustainability
Monte-Carlo simulation study of the two-stage percolation transition in enhanced binary trees
We perform Monte-Carlo simulations to study the Bernoulli () bond
percolation on the enhanced binary tree which belongs to the class of
nonamenable graphs with one end. Our numerical results show that the system has
two different percolation thresholds and . All the points in
the intermediate phase are critical and there exist
infinitely many infinite clusters in the intermediate phase. In this phase the
corresponding fractal exponent continuously increases with from zero to
unity.Comment: 4 pages, 6 figure
Phase Transition of the Ising model on a Hyperbolic Lattice
The matrix product structure is considered on a regular lattice in the
hyperbolic plane. The phase transition of the Ising model is observed on the
hyperbolic lattice by means of the corner-transfer-matrix
renormalization group (CTMRG) method. Calculated correlation length is always
finite even at the transition temperature, where mean-field like behavior is
observed. The entanglement entropy is also always finite.Comment: 4 pages, 3 figure
Irreducible Representations of Diperiodic Groups
The irreducible representations of all of the 80 diperiodic groups, being the
symmetries of the systems translationally periodical in two directions, are
calculated. To this end, each of these groups is factorized as the product of a
generalized translational group and an axial point group. The results are
presented in the form of the tables, containing the matrices of the irreducible
representations of the generators of the groups. General properties and some
physical applications (degeneracy and topology of the energy bands, selection
rules, etc.) are discussed.Comment: 30 pages, 5 figures, 28 tables, 18 refs, LaTex2.0
Heat flow of the Earth and resonant capture of solar 57-Fe axions
In a very conservative approach, supposing that total heat flow of the Earth
is exclusively due to resonant capture inside the Earth of axions, emitted by
57-Fe nuclei on Sun, we obtain limit on mass of hadronic axion: m_a<1.8 keV.
Taking into account release of heat from decays of 40-K, 232-Th, 238-U inside
the Earth, this estimation could be improved to the value: m_a<1.6 keV. Both
the values are less restrictive than limits set in devoted experiments to
search for 57-Fe axions (m_a<216-745 eV), but are much better than limits
obtained in experiments with 83-Kr (m_a<5.5 keV) and 7-Li (m_a<13.9-32 keV).Comment: 8 page
Towards a new generation axion helioscope
We study the feasibility of a new generation axion helioscope, the most
ambitious and promising detector of solar axions to date. We show that large
improvements in magnetic field volume, x-ray focusing optics and detector
backgrounds are possible beyond those achieved in the CERN Axion Solar
Telescope (CAST). For hadronic models, a sensitivity to the axion-photon
coupling of \gagamma\gtrsim {\rm few} \times 10^{-12} GeV is
conceivable, 1--1.5 orders of magnitude beyond the CAST sensitivity. If axions
also couple to electrons, the Sun produces a larger flux for the same value of
the Peccei-Quinn scale, allowing one to probe a broader class of models. Except
for the axion dark matter searches, this experiment will be the most sensitive
axion search ever, reaching or surpassing the stringent bounds from SN1987A and
possibly testing the axion interpretation of anomalous white-dwarf cooling that
predicts of a few meV. Beyond axions, this new instrument will probe
entirely unexplored ranges of parameters for a large variety of axion-like
particles (ALPs) and other novel excitations at the low-energy frontier of
elementary particle physics.Comment: 37 pages, 11 figures, accepted for publication in JCA
The International Axion Observatory (IAXO)
The International Axion Observatory (IAXO) is a new generation axion
helioscope aiming at a sensitivity to the axion-photon coupling of a few
10 GeV, i.e. 1 - 1.5 orders of magnitude beyond the one currently
achieved by CAST. The project relies on improvements in magnetic field volume
together with extensive use of x-ray focusing optics and low background
detectors, innovations already successfully tested in CAST. Additional physics
cases of IAXO could include the detection of electron-coupled axions invoked to
solve the white dwarfs anomaly, relic axions, and a large variety of more
generic axion-like particles (ALPs) and other novel excitations at the
low-energy frontier of elementary particle physics. This contribution is a
summary of our paper [1] to which we refer for further details.Comment: 4 pages, 2 figures. To appear in the proceedings of the 7th Patras
Workshop on Axions, WIMPs and WISPs, Mykonos, Greece, 201
Periodic boundary conditions on the pseudosphere
We provide a framework to build periodic boundary conditions on the
pseudosphere (or hyperbolic plane), the infinite two-dimensional Riemannian
space of constant negative curvature. Starting from the common case of periodic
boundary conditions in the Euclidean plane, we introduce all the needed
mathematical notions and sketch a classification of periodic boundary
conditions on the hyperbolic plane. We stress the possible applications in
statistical mechanics for studying the bulk behavior of physical systems and we
illustrate how to implement such periodic boundary conditions in two examples,
the dynamics of particles on the pseudosphere and the study of classical spins
on hyperbolic lattices.Comment: 30 pages, minor corrections, accepted to J. Phys.
- …