17,824 research outputs found
Determining the habitat use of Varecia variegata in Maromizaha Protected Area, Madagascar
Understanding the interaction between frugivores and their habitat is necessary for both primate and forest preservation. In Madagascar, Varecia variegata, are the most highly frugivorous lemur in the Lemuridae family This project examined the habitat use of a troop of V. variegata (the black and white ruffed lemur) in Maromizaha, a newly protected area just outside of the village, Anevoka, in Madagascar. The hypothesis tested is that the size, location, flowering status, and species identity of trees selected by lemurs for particular activities (feeding, resting, sleeping) differ from the distribution of trees in the forest as a whole. There is evidence that V. variegata selected trees with significantly different CBH (F1,733=24.8, p= 7.956e-07), height (F1,733=20.64, p= 6.488e-06), and phenology compared to the general habitat observed in the identified territory
Convection displacement current and alternative form of Maxwell-Lorentz equations
Some mathematical inconsistencies in the conventional form of Maxwell's
equations extended by Lorentz for a single charge system are discussed. To
surmount these in framework of Maxwellian theory, a novel convection
displacement current is considered as additional and complementary to the
famous Maxwell displacement current. It is shown that this form of the
Maxwell-Lorentz equations is similar to that proposed by Hertz for
electrodynamics of bodies in motion. Original Maxwell's equations can be
considered as a valid approximation for a continuous and closed (or going to
infinity) conduction current. It is also proved that our novel form of the
Maxwell-Lorentz equations is relativistically invariant. In particular, a
relativistically invariant gauge for quasistatic fields has been found to
replace the non-invariant Coulomb gauge. The new gauge condition contains the
famous relationship between electric and magnetic potentials for one uniformly
moving charge that is usually attributed to the Lorentz transformations. Thus,
for the first time, using the convection displacement current, a physical
interpretation is given to the relationship between the components of the
four-vector of quasistatic potentials. A rigorous application of the new gauge
transformation with the Lorentz gauge transforms the basic field equations into
an independent pair of differential equations responsible for longitudinal and
transverse fields, respectively. The longitudinal components can be interpreted
exclusively from the standpoint of the instantaneous "action at a distance"
concept and leads to necessary conceptual revision of the conventional
Faraday-Maxwell field. The concept of electrodynamic dualism is proposed for
self-consistent classical electrodynamics. It implies simultaneous coexistenceComment: ReVTeX file, 29pp., no figure
Folding and Misfolding of Designed Heteropolymer Chains with Mutations
We study the impact of mutations (changes in amino acid sequence) on the
thermodynamics of simple protein-like heteropolymers consisting of N monomers,
representing the amino acid sequence. The sequence is designed to fold into its
native conformation on a cubic lattice. It is found that quite a large
fraction, between one half and one third of the substitutions, which we call
'cold errors', make important contributions to the dynamics of the folding
process, increasing folding times typically by a factor of two, the altered
chain still folding into the native structure. Few mutations ('hot errors'),
have quite dramatic effects, leading to protein misfolding. Our analysis
reveals that mutations affect primarily the energetics of the native
conformation and to a much lesser extent the ensemble of unfolded
conformations, corroborating the utility of the ``energy gap'' concept for the
analysis of folding properties of protein-like heteropolymers.Comment: 12 pages, Latex (Revtex
Representativeness of samples from general practice lists in epidemiological studies: case-control study
Ethical constraints often prevent epidemiological studies from evaluating the impact of non-participation. Particular problems may arise when subjects fail to respond to an approach by researchers or when they cannot be contacted because of inaccurate contact details or a doctor's refusal to give permission for their patient to be approached. If these subjects differ from those subjects who agree or decline to participate then the validity and generalisability of the study may be compromised. We investigated these issues in a case-control study of acute leukaemia in England
Interactive Music Generation with Positional Constraints using Anticipation-RNNs
Recurrent Neural Networks (RNNS) are now widely used on sequence generation
tasks due to their ability to learn long-range dependencies and to generate
sequences of arbitrary length. However, their left-to-right generation
procedure only allows a limited control from a potential user which makes them
unsuitable for interactive and creative usages such as interactive music
generation. This paper introduces a novel architecture called Anticipation-RNN
which possesses the assets of the RNN-based generative models while allowing to
enforce user-defined positional constraints. We demonstrate its efficiency on
the task of generating melodies satisfying positional constraints in the style
of the soprano parts of the J.S. Bach chorale harmonizations. Sampling using
the Anticipation-RNN is of the same order of complexity than sampling from the
traditional RNN model. This fast and interactive generation of musical
sequences opens ways to devise real-time systems that could be used for
creative purposes.Comment: 9 pages, 7 figure
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