2,983 research outputs found
Adult Female Spruce Bedworm, \u3ci\u3eChoristoneura Fumiferana\u3c/i\u3e (Lepidoptera: Tortricidae), Dry Weight in Relationship to Pupal Fresh Weight and Case Diameter
(excerpt)
The weights of adult insects are often measured in production and population studies in order to estimate such variables as growth rates, food conversion efficiencies, fecundity, and others. For the eastern spruce budworm, Choristoneura fumiferana (Clemens), both pupal fresh weights and pupal case diameters have been measured as indicators of adult fecundity and adult dry weights (Miller 1957). However, there are no reports explicitly showing the relationship between these metric pupal variables and adult dry weights. This is the goal of this note
First- and Second Order Phase Transitions in the Holstein-Hubbard Model
We investigate metal-insulator transitions in the Holstein-Hubbard model as a
function of the on-site electron-electron interaction U and the electron-phonon
coupling g. We use several different numerical methods to calculate the phase
diagram, the results of which are in excellent agreement. When the
electron-electron interaction U is dominant the transition is to a
Mott-insulator; when the electron-phonon interaction dominates, the transition
is to a localised bipolaronic state. In the former case, the transition is
always found to be second order. This is in contrast to the transition to the
bipolaronic state, which is clearly first order for larger values of U. We also
present results for the quasiparticle weight and the double-occupancy as
function of U and g.Comment: 6 pages, 5 figure
Dynamic response functions for the Holstein-Hubbard model
We present results on the dynamical correlation functions of the
particle-hole symmetric Holstein-Hubbard model at zero temperature, calculated
using the dynamical mean field theory which is solved by the numerical
renormalization group method. We clarify the competing influences of the
electron-electron and electron-phonon interactions particularity at the
different metal to insulator transitions. The Coulomb repulsion is found to
dominate the behaviour in large parts of the metallic regime. By suppressing
charge fluctuations, it effectively decouples electrons from phonons. The
phonon propagator shows a characteristic softening near the metal to
bipolaronic transition but there is very little softening on the approach to
the Mott transition.Comment: 13 pages, 19 figure
Polymeric alkali fullerides are stable in air
Infrared transmission, electron spin resonance, and X-ray diffraction
measurements show unambiguously that RbC and KC are stable in
air, in contrast to RbC which decomposes rapidly upon exposure.
The specimens studied transform into pure C and other byproducts when
heated above 100\dd C, approximately the temperature of the orthorhombic-fcc
phase transition. The stability of these compounds raises the possibility of
applying them as protective layers for the superconducting fullerides.Comment: Scheduled for publication in Appl. Phys. Lett. 66, 20 Feb. 1995,
typeset in REVTEX v3.0 in LaTeX. Postscript file including all figures is
available on WWW http://insti.physics.sunysb.edu/~mmartin/ under my list of
publications, or will be e-mailed by request
Magnetic Field Effects on Quasiparticles in Strongly Correlated Local Systems
We show that quasiparticles in a magnetic field of arbitrary strength can
be described by field dependent parameters. We illustrate this approach in the
case of an Anderson impurity model and use the numerical renormalization group
(NRG) to calculate the renormalized parameters for the levels with spin
, , resonance width
and the effective local quasiparticle interaction . In the Kondo or strong correlation limit of the model the progressive
de-renormalization of the quasiparticles can be followed as the magnetic field
is increased. The low temperature behaviour, including the conductivity, in
arbitrary magnetic field can be calculated in terms of the field dependent
parameters using the renormalized perturbation expansion. Using the NRG the
field dependence of the spectral density on higher scales is also calculated.Comment: 15 pages, 17 figure
The Resummed Photon Spectrum in Radiative Upsilon Decays
We present a theoretical prediction for the photon spectrum in radiative
Upsilon decay including the effects of resumming the endpoint region, E_\gamma
-> M_\Upsilon/2. Our approach is based on NRQCD and the soft collinear
effective theory. We find that our results give much better agreement with data
than the leading order NRQCD prediction.Comment: 4 pages, 6 figure
Entropy/IP: Uncovering Structure in IPv6 Addresses
In this paper, we introduce Entropy/IP: a system that discovers Internet
address structure based on analyses of a subset of IPv6 addresses known to be
active, i.e., training data, gleaned by readily available passive and active
means. The system is completely automated and employs a combination of
information-theoretic and machine learning techniques to probabilistically
model IPv6 addresses. We present results showing that our system is effective
in exposing structural characteristics of portions of the IPv6 Internet address
space populated by active client, service, and router addresses.
In addition to visualizing the address structure for exploration, the system
uses its models to generate candidate target addresses for scanning. For each
of 15 evaluated datasets, we train on 1K addresses and generate 1M candidates
for scanning. We achieve some success in 14 datasets, finding up to 40% of the
generated addresses to be active. In 11 of these datasets, we find active
network identifiers (e.g., /64 prefixes or `subnets') not seen in training.
Thus, we provide the first evidence that it is practical to discover subnets
and hosts by scanning probabilistically selected areas of the IPv6 address
space not known to contain active hosts a priori.Comment: Paper presented at the ACM IMC 2016 in Santa Monica, USA
(https://dl.acm.org/citation.cfm?id=2987445). Live Demo site available at
http://www.entropy-ip.com
The Anomalous Infrared Emission of Abell 58
We present a new model to explain the excess in mid and near infrared
emission of the central, hydrogen poor dust knot in the planetary nebula (PN)
Abell 58. Current models disagree with ISO measurement because they apply an
average grain size and equilibrium conditions only. We investigate grain size
distributions and temperature fluctuations affecting infrared emission using a
new radiative transfer code and discuss in detail the conditions requiring an
extension of the classical description. The peculiar infrared emission of V605
Aql, the central dust knot in Abell 58, has been modeled with our code. V605
Aql is of special interest as it is one of only three stars ever observed to
move from the evolutionary track of a central PN star back to the post-AGB
state.Comment: 17 pages, 4 figures; accepted and to be published in Ap
Abundância relativa e sazonalidade de espécies de Chrysomya (Diptera: Calliphoridae) no Pantanal.
O gênero Chrysomya (Diptera: Calliphoridae), representado pelas espécies C. putoria, C. albiceps e C. megacephala, foi introduzido no Brasil na década de 70. Esses dípteros sinantrópicos (espécies que vivem em ambiente humano) são de interesse médico-sanitário, pois os adultos são vetores de agentes patogênicos e as larvas podem causar miíases secundárias em animais e no homem. O presente estudo objetivou conhecer a abundância relativa e a sazonalidade das espécies de Chrysomya na região do Pantanal. Capturas foram realizadas continuamente no período de novembro 2004 a junho 2006, na fazenda Nhumirim, sub-região da Nhecolândia, Pantanal sul-mato-grossense
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