448 research outputs found
Traffic control in coherence-multiplexed networks
Coherence multiplexing (CM) is a relatively unknown form of optical CDMA, which is particulary suitable in medium bit rate, short-range optical networks like LANs. The main purpose of the technique is to allow multiple users to transmit through a common optical fiber simultaneously. When this number is too large, however, the BER will become unacceptably high. Therefore a protocol is needed to control the traffic. In this paper several protocols are presented. An adapted version of synchronous TDMA, two new protocols and a central control unit will be proposed and discussed. Finally, the protocols will be compared with respect to performance and practical implementation aspects
Compactness for Holomorphic Supercurves
We study the compactness problem for moduli spaces of holomorphic supercurves
which, being motivated by supergeometry, are perturbed such as to allow for
transversality. We give an explicit construction of limiting objects for
sequences of holomorphic supercurves and prove that, in important cases, every
such sequence has a convergent subsequence provided that a suitable extension
of the classical energy is uniformly bounded. This is a version of Gromov
compactness. Finally, we introduce a topology on the moduli spaces enlarged by
the limiting objects which makes these spaces compact and metrisable.Comment: 38 page
Systematic Revision of Elaphoglossum (Dryopteridaceae) in French Polynesia, with the Description of Three New Species
Species descriptions and a key for the nine species of Elaphoglossum (Dryopteridaceae) in French Polynesia are provided. Three new species are described: E. austromarquesense from the southern Marquesas Islands, E. florencei from Raiatea and Moorea, and E. meyeri from Rapa. Each species is illustrated by a line drawing of the habit, and spore images using a scanning electron microscope. Images of scales, one of the most important diagnostic characters in the genus, are also included. © 2008 The Linnean Society of London
New obstructions to symplectic embeddings
In this paper we establish new restrictions on symplectic embeddings of
certain convex domains into symplectic vector spaces. These restrictions are
stronger than those implied by the Ekeland-Hofer capacities. By refining an
embedding technique due to Guth, we also show that they are sharp.Comment: 80 pages, 3 figures, v2: improved exposition and minor corrections,
v3: Final version, expanded and improved exposition and minor corrections.
The final publication is available at link.springer.co
The moduli space of regular stable maps
The moduli space of regular stable maps with values in a complex manifold
admits naturally the structure of a complex orbifold. Our proof uses the
methods of differential geometry rather than algebraic geometry. It is based on
Hardy decompositions and Fredholm intersection theory in the loop space of the
target manifold.Comment: 59 pages, 2 figure
The detection of age groups by dynamic gait outcomes using machine learning approaches
Prevalence of gait impairments increases with age and is associated with mobility decline, fall risk and loss of independence. For geriatric patients, the risk of having gait disorders is even higher. Consequently, gait assessment in the clinics has become increasingly important. The purpose of the present study was to classify healthy young-middle aged, older adults and geriatric patients based on dynamic gait outcomes. Classification performance of three supervised machine learning methods was compared. From trunk 3D-accelerations of 239 subjects obtained during walking, 23 dynamic gait outcomes were calculated. Kernel Principal Component Analysis (KPCA) was applied for dimensionality reduction of the data for Support Vector Machine (SVM) classification. Random Forest (RF) and Artificial Neural Network (ANN) were applied to the 23 gait outcomes without prior data reduction. Classification accuracy of SVM was 89%, RF accuracy was 73%, and ANN accuracy was 90%. Gait outcomes that significantly contributed to classification included: Root Mean Square (Anterior-Posterior, Vertical), Cross Entropy (Medio-Lateral, Vertical), Lyapunov Exponent (Vertical), step regularity (Vertical) and gait speed. ANN is preferable due to the automated data reduction and significant gait outcome identification. For clinicians, these gait outcomes could be used for diagnosing subjects with mobility disabilities, fall risk and to monitor interventions. (This work was supported by Keep Control project, funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 721577.
Bird species involved in west nile virus epidemiological cycle in southern Québec
Despite many studies on West Nile Virus (WNV) in the US, including the reservoir role of
bird species and the summer shifts of the Culex mosquito, feeding from birds to mammals, there have
been few equivalent studies in the neighboring regions of Canada where WNV is endemic. Here,
a priority list of bird species likely involved in WNV transmission in the greater Montréal area is
constructed by combining three sources of data: (i) from WNV surveillance in wild birds (2002–2015);
(ii) blood meal analysis of Culex pipiens–restuans (CPR), the primary enzootic vectors of WNV in the
region, collected from surveillance in 2008 and 2014; (iii) literature review on the sero-prevalence/host
competence of resident birds. Each of these data sources yielded 18, 23 and 53 species, and overall,
67 different bird species were identified as potential WNV amplifiers/reservoirs. Of those identified
from CPR blood meals, Common starlings, American robins, Song sparrows and House sparrows
ranked the highest and blood meal analysis demonstrated a seasonal shift in feed preference from
birds to mammals by CPR. Our study indicates that there are broad similarities in the ecology of
WNV between our region and the northeastern US, although the relative importance of bird species
varies somewhat between regions
An exact sequence for contact- and symplectic homology
A symplectic manifold with contact type boundary induces
a linearization of the contact homology of with corresponding linearized
contact homology . We establish a Gysin-type exact sequence in which the
symplectic homology of maps to , which in turn maps to
, by a map of degree -2, which then maps to . Furthermore, we
give a description of the degree -2 map in terms of rational holomorphic curves
with constrained asymptotic markers, in the symplectization of .Comment: Final version. Changes for v2: Proof of main theorem supplemented
with detailed discussion of continuation maps. Description of degree -2 map
rewritten with emphasis on asymptotic markers. Sec. 5.2 rewritten with
emphasis on 0-dim. moduli spaces. Transversality discussion reorganized for
clarity (now Remark 9). Various other minor modification
A method for isolating and culturing placental cells from failed early equine pregnancies
Early pregnancy loss occurs in 6–10% of equine pregnancies making it the main cause of reproductive wastage. Despite this, reasons for the losses are known in only 16% of cases. Lack of viable conceptus material has inhibited investigations of many potential genetic and pathological causes. We present a method for isolating and culturing placental cells from failed early equine pregnancies. Trophoblast cells from 18/30 (60%) failed equine pregnancies of gestational ages 14–65 days were successfully cultured in three different media, with the greatest growth achieved for cells cultured in AmnioChrome™ Plus. Genomic DNA of a suitable quality for molecular assays was also isolated from 29/30 of these cases. This method will enable future investigations determining pathologies causing EPL
Spectroscopic studies on photoinduced reactions of the anticancer prodrug, trans,trans,trans-[Pt(N3)2(OH)2(py)2]
The photodecomposition mechanism of trans,trans,trans-[Pt(N3)2(OH)2(py)2] (1, py = pyridine), an anticancer prodrug candidate, was probed using complementary Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR), transient electronic absorption and UV-Vis spectroscopy. Data fitting using Principal Component Analysis (PCA) and multi-curve resolution alternating least squares, suggests the formation of a trans-[Pt(N3)(py)2(OH/H2O)] intermediate and trans [Pt(py)2(OH/H2O)2] as the final product upon 420 nm irradiation of 1 in water. Rapid disappearance of the hydroxido ligand stretching vibration upon irradiation is correlated with a -10 cm-1 shift to the anti-symmetric azido vibration, suggesting a possible second intermediate. Experimental proof of subsequent dissociation of azido ligands from platinum is presented, where at least one hydroxyl radical is formed in the reduction of Pt(IV) to Pt(II). Additionally, the photoinduced reaction of 1 with 5'-guanosine monophosphate was studied, and the identity of key photoproducts was assigned with the help of ATR FTIR spectroscopy, mass spectrometry and DFT calculations. The identification of marker bands for photoproducts, e.g. trans-[Pt(N3)(py)2(5'-GMP)] and trans-[Pt(py)2(5'-GMP)2], will aid elucidation of the chemical and biological mechanism of anticancer action of 1. In general, these studies demonstrate the potential of vibrational spectroscopic techniques as promising tools for studying such metal complexes
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