415 research outputs found
Keeping pace with climate change : what is wrong with the evolutionary potential of upper thermal limits?
The potential of populations to evolve in response to ongoing climate change is partly conditioned by the presence of heritable genetic variation in relevant physiological traits. Recent research suggests that Drosophila melanogaster exhibits negligible heritability, hence little evolutionary potential in heat tolerance when measured under slow heating rates that presumably mimic conditions in nature. Here, we study the effects of directional selection for increased heat tolerance using Drosophila as a model system. We combine a physiological model to simulate thermal tolerance assays with multilocus models for quantitative traits. Our simulations show that, whereas the evolutionary response of the genetically determined upper thermal limit (CTmax) is independent of methodological context, the response in knockdown temperatures varies with measurement protocol and is substantially (up to 50%) lower than for CTmax. Realized heritabilities of knockdown temperature may grossly underestimate the true heritability of CTmax. For instance, assuming that the true heritability of CTmax in the base population is h² = 0.25, realized heritabilities of knockdown temperature are around 0.08-0.16 depending on heating rate. These effects are higher in slow heating assays, suggesting that flawed methodology might explain the apparently limited evolutionary potential of cosmopolitan D. melanogaster
Aerosol number-to-volume-relationship and relative humidity in the eastern Atlantic
J. Geophys. Res ., 105, 1987-1995.Measurementsa cquiredf rom the Office of Naval Research( ONR) Pelican research
aircraftd uringt he secondA erosolC haracterizationE xperiment( ACE 2) are analyzedt o derive
valuesf or the dry (RH = 40%) aerosonl umber-to-volumrea tio in the submicrons izer ange. This
ratioi s foundto ber elativelyc onstanwt,i tha meanv alueo f 168_ +2 1 gm- 3,i n agreemenwti th
previouss tudiese lsewhere.T he impacto f ambientr elativeh umidity (RH) on the dry
number-to-volumies alsoq uantifieda nd a procedurefo r estimatingth e dry from the ambientr atio
established.F inally, the feasibilityo f a remoter etrievalo f the aerosoln umberc oncentrationin
the submicrons izer ange,e ssentiallyth e cloudc ondensation ucleusc oncentrationa ctive at a
nominal0 .2% supersaturationis, partially assessed
A Probabilistic Analysis of Kademlia Networks
Kademlia is currently the most widely used searching algorithm in P2P
(peer-to-peer) networks. This work studies an essential question about Kademlia
from a mathematical perspective: how long does it take to locate a node in the
network? To answer it, we introduce a random graph K and study how many steps
are needed to locate a given vertex in K using Kademlia's algorithm, which we
call the routing time. Two slightly different versions of K are studied. In the
first one, vertices of K are labelled with fixed IDs. In the second one,
vertices are assumed to have randomly selected IDs. In both cases, we show that
the routing time is about c*log(n), where n is the number of nodes in the
network and c is an explicitly described constant.Comment: ISAAC 201
Anisotropic vortex pinning in superconductors with a square array of rectangular submicron holes
We investigate vortex pinning in thin superconducting films with a square
array of rectangular submicron holes ("antidots"). Two types of antidots are
considered: antidots fully perforating the superconducting film, and "blind
antidots", holes that perforate the film only up to a certain depth. In both
systems, we observe a distinct anisotropy in the pinning properties, reflected
in the critical current Ic, depending on the direction of the applied
electrical current: parallel to the long side of the antidots or perpendicular
to it. Although the mechanism responsible for the effect is very different in
the two systems, they both show a higher critical current and a sharper
IV-transition when the current is applied along the long side of the
rectangular antidots
Stomach One-Point Cancer: One Case Report and Literature Review
Gastric cancer is one of the most common cancers and one of themost frequent causes of cancer deaths worldwide. Early detection andaccurate preoperative staging of gastric cancer is essential for planning optimal therapy such as endoscopic mucosal resection or gastric resection and offers the best prognosis. With advanced technology in diagnostic instruments and the mass screening, early gastric cancer has been detected easier. One-point cancer of gastric is a special type of early gastric cancer[1]. Diagnosis of one-point cancer of gastric is important for both the immediate treatment and the prognosis. There is still no consensus on the operation extent and postoperative treatment for patients with one-point cancer of gastric. Learned from previous reports[2-5], we know that existed in the superfi cial layer of the gastric mucosa and the superfi cial ulcer is one of the important characteristics of one point cancer of gastric. Herein, we report a case of one point cancer of gastric with the appearance of a deep infi ltrating ulcer. To the best of our knowledge, no such type of one point cancer of gastric has been reported
Determinant Representations of Correlation Functions for the Supersymmetric t-J Model
Working in the -basis provided by the factorizing -matrix, the scalar
products of Bethe states for the supersymmetric t-J model are represented by
determinants. By means of these results, we obtain determinant representations
of correlation functions for the model.Comment: Latex File, 41 pages, no figure; V2: minor typos corrected, V3: This
version will appear in Commun. Math. Phy
Drinfeld twist and symmetric Bethe vectors of the open XYZ chain with non-diagonal boundary terms
With the help of the Drinfeld twist or factorizing F-matrix for the
eight-vertex solid-on-solid (SOS) model, we find that in the F-basis provided
by the twist the two sets of pseudo-particle creation operators simultaneously
take completely symmetric and polarization free form. This allows us to obtain
the explicit and completely symmetric expressions of the two sets of Bethe
states of the model.Comment: Latex file, 25 page
An Optimal Broadcast Algorithm for Content-Addressable Networks
International audienceStructured peer-to-peer networks are powerful underlying structures for communication and storage systems in large-scale setting. In the context of the Content-Addressable Network (CAN), this paper addresses the following challenge: how to perform an efficient broadcast while the local view of the network is restricted to a set of neighbours? In existing approaches, either the broadcast is inefficient (there are dupli- cated messages) or it requires to maintain a particular structure among neighbours, e.g. a spanning tree. We define a new broadcast primitive for CAN that sends a minimum number of messages while covering the whole network, without any global knowledge. Currently, no other al- gorithm achieves those two goals in the context of CAN. In this sense, the contribution we propose in this paper is threefold. First, we pro- vide an algorithm that sends exactly one message per recipient without building a global view of the network. Second, we prove the absence of duplicated messages and the coverage of the whole network when using this algorithm. Finally, we show the practical benefits of the algorithm throughout experiments
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
- …