Interference Aspects of Adaptive Modems over Slow Rayleigh Fading Channels

Adaptive modulation can achieve channel capacity gains by adapting the number of bits per transmission symbol on a burst-by-burst basis, in harmony with channel quality fluctuations. This is demonstrated in the paper for target bit error rates of 1 and 0.01%, respectively, in comparison to conventional fixed modems. However, the achievable gains depend strongly on the prevalent interference levels and hence interference cancellation is invoked on the basis of adjusting the demodulation decision boundaries after estimating the interfering channel’s magnitude and phase. Using the modem-mode switching levels of Table X and with the aid of interference cancellation, target BERs of 1 and 0.01% can be maintained over slow-fading channels for a wide range of channel Signal-to-noise ratios (SNR) and Signal-to-interference ratios (SIR), as seen in Figs. 20 and 21, respectively. Index Terms—Burst-by-burst adaptive modulation (modems), cochannel interference, interference cancellation

Individualized ovarian stimulation in IVF/ICSI treatment : it is time to stop using high FSH doses in predicted low responders

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Creativity in savant artists with autism

Background: Individuals with autism spectrum disorder (ASD) often display impairments in creativity, yet savant artists with ASD can produce highly novel and original artistic outputs. To date, there have been no systematic attempts to explore creativity in savant artists with ASD. Methods: Nine savant artists with ASD were compared with nine talented artists, nine non-artistically talented individuals with ASD, and nine individuals with moderate learning difficulties (MLD), on tasks in and out of their domain of expertise. This was to ascertain whether the performance of the savant artists was related to their artistic ability, their diagnosis of ASD or their level of intellectual functioning. Results: On a drawing task (the Torrance Test of Creative Thinking; Torrance, 1974), the responses of the art students were more creative (scoring higher on measures of fluency, originality, elaboration and flexibility) than the savant, ASD and MLD groups. However, the savants did produce more elaborative responses than the ASD and MLD groups. On a non-drawing construction task (figural synthesis; Finke & Slayton, 1988), the savants produced more original outputs than the ASD and MLD groups (scoring similarly to the art students). No group differences were found regarding fluency on this task. Conclusions: On standardised creativity tasks, savant artists with ASD display high levels of elaboration (on drawing tasks) and originality (on non-drawing construction tasks), relative to groups with ASD or MLD. High elaboration and originality may result from a local processing bias, coupled with artistic talent, in this group

Young women's opinions on the use of a blood test to predict the possibility of premature ovarian failure: a qualitative study

The anti-Müllerian hormone (AMH) test is increasingly being used to predict the age when women will enter menopause, signalling the end of their reproductive life. However, the accuracy of the AMH test varies widely. In this qualitative study, we asked young women of three differing education levels about the possibility of predicting premature ovarian failure (POF), defined as menopause that occurs before the age of 40. A total of 15 face-to-face semi-structured interviews were conducted. The overarching theme was 'considering the possibility of predicting POF', and the three interpretive themes were (i) limited fertility knowledge, (ii) preconditions for pregnancy and (iii) desire to have children. The interview was their first awareness of the concept of POF. All the women who participated in this study wished to have children at some point later in life and tended to think more about fulfilling preconditions before getting pregnant than about their actual fertility. Most participants (n = 8) were interested in the AMH test regardless of their education level. Five participants wanted to take the test in the future. This research provides some insight into young women's current thoughts about the possibility of predicting POF with an AMH test

Electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ

We study the electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ by means of density-functional band theory, Hubbard model calculations, and angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal significant quantitative and qualitative discrepancies to band theory. We demonstrate that the dispersive behavior as well as the temperature-dependence of the spectra can be consistently explained by the finite-energy physics of the one-dimensional Hubbard model at metallic doping. The model description can even be made quantitative, if one accounts for an enhanced hopping integral at the surface, most likely caused by a relaxation of the topmost molecular layer. Within this interpretation the ARPES data provide spectroscopic evidence for the existence of spin-charge separation on an energy scale of the conduction band width. The failure of the one-dimensional Hubbard model for the {\it low-energy} spectral behavior is attributed to interchain coupling and the additional effect of electron-phonon interaction.Comment: 18 pages, 9 figure

Advances in ab-initio theory of Multiferroics. Materials and mechanisms: modelling and understanding

Within the broad class of multiferroics (compounds showing a coexistence of magnetism and ferroelectricity), we focus on the subclass of "improper electronic ferroelectrics", i.e. correlated materials where electronic degrees of freedom (such as spin, charge or orbital) drive ferroelectricity. In particular, in spin-induced ferroelectrics, there is not only a {\em coexistence} of the two intriguing magnetic and dipolar orders; rather, there is such an intimate link that one drives the other, suggesting a giant magnetoelectric coupling. Via first-principles approaches based on density functional theory, we review the microscopic mechanisms at the basis of multiferroicity in several compounds, ranging from transition metal oxides to organic multiferroics (MFs) to organic-inorganic hybrids (i.e. metal-organic frameworks, MOFs)Comment: 22 pages, 9 figure

Spin, charge and orbital ordering in ferrimagnetic insulator YBaMn2_2O5_5

The oxygen-deficient (double) perovskite YBaMn$_2$O$_5$, containing corner-linked MnO$_5$ square pyramids, is found to exhibit ferrimagnetic ordering in its ground state. In the present work we report generalized-gradient-corrected, relativistic first-principles full-potential density-functional calculations performed on YBaMn$_2$O$_5$ in the nonmagnetic, ferromagnetic and ferrimagnetic states. The charge, orbital and spin orderings are explained with site-, angular momentum- and orbital-projected density of states, charge-density plots, electronic structure and total energy studies. YBaMn$_2$O$_5$ is found to stabilize in a G-type ferrimagnetic state in accordance with experimental results. The experimentally observed insulating behavior appears only when we include ferrimagnetic ordering in our calculation. We observed significant optical anisotropy in this material originating from the combined effect of ferrimagnetic ordering and crystal field splitting. In order to gain knowledge about the presence of different valence states for Mn in YBaMn$_2$O$_5$ we have calculated $K$-edge x-ray absorption near-edge spectra for the Mn and O atoms. The presence of the different valence states for Mn is clearly established from the x-ray absorption near-edge spectra, hyperfine field parameters and the magnetic properties study. Among the experimentally proposed structures, the recently reported description based on $P$4/$nmm$ is found to represent the stable structure

Cumulative live birth rates in low-prognosis women

No external funds were obtained for the present study. The OPTIMIST study was funded by The Netherlands Organization for Health Research and Development (ZonMW number 171102020).Peer reviewedPublisher PD