Search results for " frequency"
showing 10 items of 1398 documents
An Improved Receiver Architecture for Cyclic-Prefixed OFDM
2009
A novel Orthogonal Frequency Division Multiplexing receiver architecture to be employed with standard (e.g. Wireless LAN) transmitters is proposed. It features enhanced error-rate performance with flexible computational complexity and robustness to imperfect channel estimation. It is based on exploitation of the redundancy available in the cyclic prefix after cancellation of interference from the previous block. In order to show the effectiveness of our proposal, a number of comparisons to the standard per-subcarrier receiver and a previously existing method are reported.
On the correlation of temperature harmonic content with energy dissipation in C45 steel samples under fatigue loading
2022
Fatigue damage onset involves a transformation of mechanical energy. This is in part spent into work of plastic deformation and fracture and in part transformed into heat. Therefore, different thermomechanical heat sources are activated during a fatigue loading cycle, resulting in a temperature modulation that can be characterized by its frequency content. Several studies have monitored the temperature on samples undergoing high-cycle fatigue, measuring specific thermomechanical metrics which could serve as indicators of damage evolution. The present work evaluates the harmonic content of temperature, to investigate its correlation with the material dissipation. The harmonic terms investiga…
Computational evidence that frequency trajectory theory does not oppose but emerges from age-of-acquisition theory.
2012
International audience; According to the age-of-acquisition hypothesis, words acquired early in life are processed faster and more accurately than words acquired later. Connectionist models have begun to explore the influence of the age/order of acquisition of items (and also their frequency of encounter). This study attempts to reconcile two different methodological and theoretical approaches (proposed by Lambon Ralph & Ehsan, 2006 and Zevin & Seidenberg, 2002) to age-limited learning effects. The current simulations extend the findings reported by Zevin and Seidenberg (2002) that have shown that frequency trajectories (FTs) have limited and specific effects on word-reading tasks. Using th…
Has long-term metal exposure induced changes in life history traits and genetic diversity of the enchytraeid worm Cognettia sphagnetorum (Vejd.)?
2004
We studied whether long-term metal exposure has affected life history traits, population growth patterns and genetic diversity of the asexual enchytraeid worm Cognettia sphagnetorum (Vejd.). Enchytraeids from metal contaminated and uncontaminated forest soil were compared by growing them individually in the laboratory and by following their population development in patchily Cu contaminated microcosms. Genetic differences between the two native populations were studied using allozyme electrophoresis. Individuals from the contaminated site had slower growth rate and they produced fewer fragments of larger size when compared to individuals from the uncontaminated site. In patchily Cu contamin…
Tracing European Founder Lineages in the Near Eastern mtDNA Pool
2000
Founder analysis is a method for analysis of nonrecombining DNA sequence data, with the aim of identification and dating of migrations into new territory. The method picks out founder sequence types in potential source populations and dates lineage clusters deriving from them in the settlement zone of interest. Here, using mtDNA, we apply the approach to the colonization of Europe, to estimate the proportion of modern lineages whose ancestors arrived during each major phase of settlement. To estimate the Palaeolithic and Neolithic contributions to European mtDNA diversity more accurately than was previously achievable, we have now extended the Near Eastern, European, and northern-Caucasus d…
Acoustic methods for measuring the porosities of porous materials incorporating dead-end pores
2013
International audience; The acoustic properties of porous materials containing dead-end (DE) pores have been proposed by Dupont et al. [J. Appl. Phys. 110, 094903 (2011)]. In the theoretical description, two physical parameters were defined (the dead-end porosity and the average length of the dead-end pores). With the knowledge of the open porosity (measured with non-acoustic methods), and the measurement of kinematic porosity (also called the Biot porosity in this article), it is possible to deduce the dead-end porosity. Two acoustic methods for measuring the Biot porosity for a wide range of porosities are proposed. These methods are based on acoustic transmission and on the low and high …
400– to 1000–nm imaging spectrometer based on acousto-optic tunable filters
2004
An imaging spectrometer covering the 400-1000 nm band has been conceived and developed. The system is based on an Acousto-Optic Tunable Filter (AOTF) attached to a high performance digital camera. The AOTF permits the selection of spectral bands with an RF signal in the range of 70-210 MHz. The range is covered using two transducers attached to a single crystal. Although the idea is not new it covers a broader spectrum than previous systems. It includes a telecentric optical system that enhances system efficiency, by ensuring that the chief ray of each light cone emerges out of this doublet parallel to the optical axes. Additionally, an smart choice of integration time reduces the dependenc…
The development of “junk”. Irregularization strategies of have and say in the Germanic languages
2001
Although it is a wellknown fact that the most frequent verbs are the most irregular ones (if not suppletive), it is rarely asked how they became irregular. This article deals with the irregularization process of two originally regular (weak) verbs, HAVE and SAY in the Germanic languages, e.g. have, but has/’s and had/’d (instead of regular *haves/*haved) or say [sei], but says [sez] and said [sed] in English. Other verbs, such as DO, GO, STAND, BE, COME, and so on, also tend to irregularizations again and again without any apparent reason. In contrast to HAVE and SAY these verbs have always been rather irregular, at least dating from their first written records.
Placental alkaline phosphatase types in Germany
1974
The phenotypes of placental alkaline phosphatase were determined in a sample of 231 Germans and 109 non-Germans. The observed gene frequencies of the German sample were \({\text{Pl}}^{{\text{S}}_{\text{1}} } {\text{ = 0}}{\text{.654}}\), \({\text{Pl}}^{{\text{F}}_{\text{1}} } {\text{ = 0}}{\text{.247}}\), and \({\text{Pl}}^{{\text{I}}_{\text{1}} } {\text{ = 0}}{\text{.097}}\). No association could be found with placental weight. Lower birth weight was correlated with an increase of the \({\text{Pl}}^{{\text{I}}_{\text{1}} } \) gene frequency.
The recipient CYP2D6 allele 4-associated poor metabolizer status correlates with an early fibrosis development after liver transplantation
2011
Summary CYP2D6 is part of the cytochrome P450 system, which catalyzes biotransformation of endogenous substrates and xenobiotics. Approximately 10% of the Caucasian population has two null alleles, resulting in a poor metabolizer (PM) status. Mostly, allele four (CYP2D6*4) is responsible for the PM status, which is suspected to be associated with an accelerated fibrosis progression (FP). The aim of the present study was to analyze the role of the CYP2D6*4 genotype for FP after liver transplantation (LT). Genotypes were determined in liver biopsies (donor) and peripheral blood (recipient) by fluorescence resonance energy transfer. Data were correlated with clinical variables and risk factors…