Scoring of nonmetric cranial traits: a methodological approach

The purpose of the present study was to analyse the replicability of the scoring of discontinuous traits. This was assessed on a sample of 100 skulls from the Frassetto collection (Dipartimento di Biologia Evoluzionistica Sperimentale of Bologna University) analysed through intraobserver comparisons: the discontinuous traits were determined on the same skulls and by the same observer on 3 separate occasions. The scoring was also assessed through interobserver comparisons: 3 different observers performed an independent survey on the same skulls. The results show that there were no significant differences in the discontinuous trait frequencies between the 3 different scorings by the same observer, but there were sometimes significant differences between different observers. Caution should thus be taken in applying the frequencies of these traits to population research. After an indispensable control of material conditions (subject age included), consideration must be given to standardisation procedures between observers, otherwise this may be an additional source of variability in cranial discontinuous trait scoring.     

Direct Simulation of Charge Transport in Graphene Nanoribbons

Graphene nanoribbons are considered as one of the most promising ways todesign electron devices where the active area is made of graphene. In fact, graphenenanoribbons present a gap between the valence and the conduction bands as in standard semiconductors such as Si or GaAs, at variance with large area graphene which isgapless, a feature that hampers a good performance of graphene field effect transistors.To use graphene nanoribbons as a semiconductor, an accurate analysis of theirelectron properties is needed. Here, electron transport in graphene nanoribbons isinvestigated by solving the semiclassical Boltzmann equation with a discontinuousGalerkin method. All the electron-phonon scattering mechanisms are included. Theadopted energy band structure is that devised in [1] while according to [2] the edgeeffects are described as an additional scattering stemming from the Berry-Mondragonmodel which is valid in presence of edge disorder. With this approach a spacial 1Dtransport problem has been solved, even if it remains two dimensional in the wave-vector space. A degradation of charge velocities, and consequently of the mobilities, isfound by reducing the nanoribbon width due mainly to the edge scattering.     

A Study of Several Artificial Viscosity Models within the Discontinuous Galerkin Framework

Dealing with strong shocks while retaining low numerical dissipation traditionally has been one of the major challenges for high order methods like discontinuous Galerkin (DG). In the literature, shock capturing models have been designed forDG based on various approaches, such as slope limiting, (H)WENO reconstruction, aposteriori sub-cell limiting, and artificial viscosity, among which a subclass of artificial viscosity methods are compared in the present work. Four models are evaluated,including a dilation-based model, a highest modal decay model, an averaged modaldecay model, and an entropy viscosity model. Performance for smooth, non-smoothand broadband problems are examined with typical one- and two-dimensional cases.     

Electroclinical Correlation Examined by Simultaneous VTR-EEG Monitoring in a Patient with Complex Partial Status Epilepticus

Abstract: We discussed the electroclinical correlation of complex partial status epilepticus (CPSE) followed up by simultaneous VTR-EEG monitoring. An eight-year-old boy had repetitive seizures lasting for 30 to 90 minutes in addition to ordinary seizures with typical oral automatism of a few minutes duration. This case fulfilled the criteria for diagnosis of CPSE by Treiman el al . (1983), and was classified as the discontinuous type of CPSE described by Gastaut et al . (1975). The clinical symptoms were characterized by a repeated occurrence of psychomotor arrest and automatic phases. The EEG showed an alternate appearance of two phases. One was characterized by 7 to 8 Hz theta or slow alpha waves and the other by 4 to 6 Hz theta waves, respectively.     

Andrology: An auto-controlled study in in-vitro fertilization reveals the benefit of Percoll centrifugation to swim-up in the preparation of poor-quality semen

The efficiency of spermatozoa prepared by swim-up or by Percollcentrifugation was assessed in an in-vitro fertilization programmeon 71 semen samples of a well-defined quality [total numberof type A (WHO criteria) motile spermatozoa]: category I (n= 21) with > 100 x 10⁶, II (n = 31) with 15–100 x 10⁶,III (n = 11) with 5–15 x 10⁶ and IV (n = 8) with <5 x 10⁶ type A motile spermatozoa. Oocytes were inseminated4 h after oocyte retrieval, alternately with spermatozoa derivedfrom swim-up and Percoll preparation. Both selection proceduresresulted in a significantly higher (P < 0.001) percentagemotility as compared to fresh semen. For low-quality samples(III and IV), however, swim-up was more effective in selectinghighly motile (P = 0.004) and morphologically normal spermatozoa(P < 0.05). For high-quality samples, this difference mighthave been masked by introducing a swim-up step to remove Percollparticles. Regardless of the initial sperm quality, the meanfertilization rate was significantly higher (P = 0.003) whenPercoll-treated spermatozoa were used for insemination (51.3versus 37.8%). For semen of groups I and II, no difference infertilization capacity was observed according to the sperm preparationmethod. Despite the lower percentage motility and normal morphologyfor the Percoll compared to the swim-up treatment in groupsIII and IV, fertilizing capacity was significantly (P < 0.001)in favour of this selection method (65.3 versus 26.5% in groupIII, 47.6 versus 11.6% in group IV). Based on these results,it may be concluded that a subgroup of patients exhibiting poorsemen quality can benefit from Percoll semen preparation interms of improved fertilizing capacity.     

APPROXIMATE LINEARIZATION OF CONTROL SYSTEMS WITH DISCONTINUOUS NON-LINEARITIES

The class of systems containing elements with discontinuous input-output characteristics (such as jumps, hysteresis, etc.) presents a serious challenge to control specialists. They are so difficult to treat analytically that they are normally dealt with using heuristic methods. In this paper a mathematical framework for such problems is presented and precise criteria for measuring the non-linearity are introduced. Linearization is considered in a restricted but realistic sense (on average or at discrete times only). In this context the most common practical techniques such as dithering and pulse width modulation are analysed. In addition, a simple new approach for feedforward control is developed. It produces a locally optimal control, providing results that are superior to those from more standard precompensation techniques. An application of these ideas to a small travelling wave motor is included. Such motors have considerable dry friction and therefore provide significant examples of the kind of systems under consideration.     

Improvement of survival and fertilizing capacity of human spermatozoa in an IVF programme by selection on discontinuous Percoll gradients

Two techniques for the separation of spermatozoa were compared: swim-up migration (SUM) and centrifugation on a discontinuous Percoll gradient (CPG). Their respective effects on sperm motility were analysed by computer-assisted videomicrography in either normal or asthenozoospermic groups. In both groups, there was no difference in any of the motion parameters between the two treatments after 1-h incubation. However, a clear difference was observed after 24 h when excellent motility was retained only in the CPG-treated group. A total of 350 ejaculates were produced by the husbands of women undergoing oocyte retrieval in an IVF programme. Spermatozoa were treated by CPG when the infertility was due to poor quality spermatozoa (n = 91), when there was a known previous history of semen infection (n = 73) or when frozen semen, originating from a donor, was used (n = 36). In all other cases (n = 150), spermatozoa were treated by SUM. The cleavage rates obtained were 32.2, 70.1, 60.9 and 68.6% respectively in the four categories. The clinical pregnancy rates per oocyte retrieval were 19.8, 31.5, 22.2 and 18.0% respectively. Forty-eight births occurred in the CPG group: 28 boys and 20 girls, all normal. We conclude that CPG is useful, both in cases of poor semen quality and in tubal infertility, in which the clinical pregnancy rate increased significantly from 18.0 to 31.5%.     

Guidance and control laws design for a switched system with discontinuous actuators

Guidance and control laws design for a switched flight system with discontinuous actuators is dealt with in this paper. Firstly, a missile equipped with discontinuous side jets is introduced. Secondly, the side‐jet missile is modeled with an impulsive switched system. Thirdly, a sliding mode control‐based discontinuous guidance law is proposed to generate guidance commands, which are suitable for on–off side jets. And a logic‐based switching law for turning on the side jets is also submitted. Fourthly, by transforming the discontinuous actuators equivalently and formulating an extended state space equation, a tracking control law is indicated to track the guidance command. Finally, simulations and comparisons are made to demonstrate the proposed algorithms. Copyright © 2016 John Wiley & Sons, Ltd.     

Mini-Percoll: a new method of semen preparation for IVF in severe male factor infertility

Conventional methods of semen preparation for IVF, such as swim-up sedimentation, regular Percoll gradients, are not very effective in the treatment of severe oligoasthenozoospermia (total motile count less than 5 X 10(6)). For these cases, a new method of sperm preparation consisting of a reduced volume of a discontinuous Percoll gradient (mini-Percoll) has been utilized. The results obtained were analysed by comparing mini-Percoll versus resuspension in two groups of patients with severe male factor infertility. In the mini-Percoll group, a statistically significant improvement (P less than 0.001) was obtained in the post-treatment seminal parameters of motility, progression and proportion of normal forms. In the resuspension group (n = 12), only eight of 108 oocytes inseminated were fertilized (7%), while in the mini-Percoll group (n = 29), 124 out of 336 oocytes were fertilized (40%) (P less than 0.001). Furthermore, in the mini-Percoll group, a higher pregnancy rate (25 versus 7%) and low abortion rate (22 versus 33%) were observed. Although more studies are necessary to confirm these preliminary data, mini-Percoll seems to be a valid laboratory tool for semen samples of extremely poor quality.     

Enrichment of MLR-activated human suppressor cells by discontinuous density-gradient centrifugation

6-day allogeneic mixed lymphocyte cultures (MLR) were fractionated on a four-step discontinuous Percoll^R gradient. The various fractions were added as regulatory cells to freshly established micro-MLRs between the original or third-party cell donors. Unspecific suppressor activity was highly enriched in gradient fraction III (density 1.069?1.062 g/ml), consisting mainly of blast-like cells. Suppressor cells were non-adherent T cells as determined by their spontaneous rosette formation with sheep erythrocytes and their susceptibility to lysis by anti-T-cell globulin plus complement. Mitomycin C treatment diminished their inhibitory capacity. In addition, gradient fraction III was also enriched with alloantigen-activated memory cells. By contrast, unprimed alloreactive cells were recovered from gradient fraction IV (density ≥ 1.070 g/ml), consisting mainly of small, resting lymphocytes.