2,304 research outputs found
The Deconstructed (or Distributed) Journal - an emerging model?
Reviews the development of the Deconstructed Journal academic publishing model. The model was first proposed in something like its present form in 1997 and further developed in 1999. Although not actively promoted elements of the model appear to be emerging spontaneously from the general developments in online academic publishing
Prolegomena to any future e-publishing model
Considers why, after nearly twenty years of development, the electronic publishing model has not replaced the paper based model for academic journals. Gives three insights that attempt to explain this: the first is the âmeans-endâ confusion of commercial publishers, the second is the failure to realise it is the purpose not the form that is important about the current journal model, and third is the failure to recognise that a net-based replacement for the journal does not necessarily need a publisher. Finally some 'ground rules' to be used when thinking about, or designing, any future electronic publishing model are proposed
On the Dissection of Rectangles into Right-Angled Isosceles Triangles
AbstractWe consider the problem of dissecting a rectangle or a square into unequal right-angled isosceles triangles. This is regarded as a generalization of the well-known and much-solved problem of dissecting such figures into unequal squares. There is an analogous âelectricalâ theory but it is based on digraphs instead of graphs and has an appropriate modification of Kirchhoff's first law. The operation of reversing all edges in the digraph is found to be of great help in the construction of âperfectâ dissected squares
Summer range fidelity of radio-collared caribou in Alaska's Central Arctic Herd
Sixty-four adult (2 + years) female caribou (Rangifer tarandus grand), radio-collared in April or May 1975 - 82, were relocated during the following June and/or July within the summer range of the Central Arctic Herd (CAH). Relocations made during the following three summers were used to assess range fidelity. Cumulative relocations of radio-collared females in the Central Arctic region were equivalent to 91% of the projected availability based on transmitter life. A chronological analysis indicates that 98%, 91%, and 82% of radio-collared females were found there one, two, and three years later; most of the progressively lower relocation success is probably attributable to transitter malfunctions rather than emigration. These observations suggest that summer range fidelity of adult females in the CAH is at least 90%, and may approach 100%
Abundance and movements of caribou in the oilfield complex near Prudhoe Bay, Alaska
We examined the distribution and movements of 141 radiocollared female caribou (Rangifer tarandus granti) of the Central Arctic Herd during summer, 1980-1993. Numbers of caribou locations within each of 5 quadrats along the arctic coast were totalled separately for days during which insects were active and inactive, and numbers of east-west and west-east crossings of each quadrat mid-line were determined from sequential observations. Both abundance and lateral movements of radiocollared females in the quadrat encompassing the intensively-developed Prudhoe Bay oilfield complex were significantly lower than in other quadrats (P < 0.001 and P < 0.00001, respectively). Avoidance of, and fewer movements within, the complex by female caribou are ostensibly in response to the dense network of production and support facilities, roads, above-ground pipelines, and the associated vehicular and human activity. Impaired access to this area constitutes a functional loss of habitat
On the non-Gaussianity from Recombination
The non-linear effects operating at the recombination epoch generate a
non-Gaussian signal in the CMB anisotropies. Such a contribution is relevant
because it represents a major part of the second-order radiation transfer
function which must be determined in order to have a complete control of both
the primordial and non-primordial part of non-Gaussianity in the CMB
anisotropies. We provide an estimate of the level of non-Gaussianity in the CMB
arising from the recombination epoch which shows up mainly in the equilateral
configuration. We find that it causes a contamination to the possible
measurement of the equilateral primordial bispectrum shifting the minimum
detectable value of the non-Gaussian parameter f^equil_NL by Delta f^equil_NL=
O(10) for an experiment like Planck.Comment: LaTeX file; 11 pages. v2: Typos corrected; references added; comments
about the effective non-linearity parameter added in Sec. IV; comments added
in the conclusions of Sec. IV. v3: References added; some clarifications
added as footnotes 4 and 6, and in Sec. 3. Matches version accepted for
publication in JCA
Coupled virus - bacteria interactions and ecosystem function in an engineered microbial system
Viruses are thought to control bacterial abundance, affect community composition and influence ecosystem function in natural environments. Yet their dynamics have seldom been studied in engineered systems, or indeed in any system, for long periods of time. We measured virus abundance in a full-scale activated sludge plant every week for two years. Total bacteria and ammonia oxidising bacteria (AOB) abundances, bacterial community profiles, and a suite of environmental and operational parameters were also monitored. Mixed liquor virus abundance fluctuated over an order of magnitude (3.18 Ă 108 â 3.41 Ă 109 virusâs mL-1) and that variation was statistically significantly associated with total bacterial and AOB abundance, community composition, and effluent concentrations of COD and NH4+- N and thus system function. This suggests viruses play a far more important role in the dynamics of activated sludge systems than previously realised and could be one of the key factors controlling bacterial abundance, community structure and functional stability and may cause reactors to fail. These finding are based on statistical associations, not mechanistic models. Nevertheless, viral associations with abiotic factors, such as pH, make physical sense giving credence to these findings and highlighting the role that physical factors play in virus ecology. Further work is needed to identify and quantify specific bacteriophage and their hosts to enable us to develop mechanistic models of the ecology of viruses in wastewater treatment systems. However, since we have shown that viruses can be related to effluent quality and virus quantification is simple and cheap, practitioners would probably benefit from quantifying viruses now
Molecular dynamics modelling of radiation damage in normal, partly inverse and inverse spinels
The radiation response of perfect crystals of MgAl2O4, partially inverted MgGa2O4
and fully inverse MgIn2O4 were investigated using molecular dynamics. Dynamical
cascades were initiated in these spinels over a range of trajectories with energies of
400 eV and 2 keV for the primary knock-on event. Collision cascades were set up on
each of the cation and anion sublattices and were monitored up to 10 ps. Simulations
in the normal MgAl2O4 spinel for the 2 keV energy regime resulted in similar defect
structures as obtained at the post-threshold 400 eV energies, with little clustering
occurring. The predominant defect configurations were split interstitials and cation
antisites. For the inverse spinels, a much wider variety of lattice imperfections was
observed. More defects were also produced due to the formation of interstitialvacancy
cation chains and oxygen crowdions
Solitary wave solution to the generalized nonlinear Schrodinger equation for dispersive permittivity and permeability
We present a solitary wave solution of the generalized nonlinear Schrodinger
equation for dispersive permittivity and permeability using a scaling
transformation and coupled amplitude-phase formulation. We have considered the
third-order dispersion effect (TOD) into our model and show that soliton shift
may be suppressed in a negative index material by a judicious choice of the TOD
and self-steepening parameter.Comment: 6 page
Fluctuations and Dissipation of Coherent Magnetization
A quantum mechanical model is used to derive a generalized Landau-Lifshitz
equation for a magnetic moment, including fluctuations and dissipation. The
model reproduces the Gilbert-Brown form of the equation in the classical limit.
The magnetic moment is linearly coupled to a reservoir of bosonic degrees of
freedom. Use of generalized coherent states makes the semiclassical limit more
transparent within a path-integral formulation. A general
fluctuation-dissipation theorem is derived. The magnitude of the magnetic
moment also fluctuates beyond the Gaussian approximation. We discuss how the
approximate stochastic description of the thermal field follows from our
result. As an example, we go beyond the linear-response method and show how the
thermal fluctuations become anisotropy-dependent even in the uniaxial case.Comment: 22 page
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