Mid-infrared optical characterization of thin SiNx membranes.

The investigation of the optical constants (e.g., the refractive index n and the extinction coefficient κ) has been performed in the mid-infrared spectrum for various silicon nitride (SiNx) configurations. By exploiting the transfer matrix method formulation, photometric measurements of transmission and reflection have been used for iteratively calculating the optical parameters of interest. To ensure the reliability of the n and κ, the same material from which such parameters were extracted was deposited for three different thicknesses, e.g., 600, 200, and 100 nm. While the former is optically characterized, the remaining two are used for validation purposes. For each experimental/calculated comparison, the average (made over the whole considered spectrum interval) of the relative error never exceeds 1.5%, which ensures the correctness of the given n and κ. For the sake of completeness, a detailed analysis of the intrinsic limitations arising from the very nature of the method will also be conducted.

Numerical emulation of Thru-Reflection-Line calibration for the de-embedding of Surface Acoustic Wave devices.

In this contribution, a rigorous numerical calibration is proposed to characterize the excitation of propagating mechanical waves by interdigitated transducers (IDTs). The transition from IDT terminals to phonon waveguides is modeled by means of a general circuit representation that makes use of Scattering Matrix (SM) formalism. In particular, the three-step calibration approach called the Thru-Reflection-Line (TRL), that is a well-established technique in microwave engineering, has been successfully applied to emulate typical experimental conditions. The proposed procedure is suitable for the synthesis/optimization of surface-acoustic-wave (SAW) based devices: the TRL calibration allows to extract/de-embed the acoustic component, namely resonator or filter, from the outer IDT structure, regardless of complexity and size of the letter. We report, as a result, the hybrid scattering parameters of the IDT transition to a mechanical waveguide formed by a phononic crystal patterned on a piezoelectric AlN membrane, where the effect of a discontinuity from periodic to uniform mechanical waveguide is also characterized. In addition, to ensure the correctness of our numerical calculations, the proposed method has been validated by independent calculations.

Prevalence of owner-reported behaviours in dogs separated from the litter at two different ages.

The present study examined the prevalence of behaviours in dogs separated from the litter for adoption at different ages. Seventy adult dogs separated from their dam and littermates and adopted between the ages of 30 and 40 days were compared with 70 adult dogs that had been taken from the litter for adoption at two months. Owners were asked to complete a questionnaire eliciting information on whether their dog exhibited potentially problematic behaviours when in its usual environment. Binary logistic regression analysis was performed to investigate whether the age at which the dog was separated from the litter might predispose it to developing undesirable behaviours. The odds of displaying destructiveness, excessive barking, fearfulness on walks, reactivity to noises, toy possessiveness, food possessiveness and attention-seeking were significantly greater for the dogs that had been removed from the litter earlier during the socialisation period. In addition, dogs purchased from a pet shop at 30 to 40 days of age were reported to exhibit some of the listed behaviours with a significantly higher frequency than dogs purchased from a pet shop at two months. No significant differences were observed with dogs obtained from other types of sources. The dogs in the youngest age group (18 to 36 months) had a higher probability of displaying destructiveness and tail chasing. These findings indicate that, compared with dogs that remained with their social group for 60 days, dogs that had been separated from the litter earlier were more likely to exhibit potentially problematic behaviours, especially if they came from a pet shop.

Scattering matrix approach to multichannel transport in many lead graphene nanoribbons.

Multichannel analysis of graphene nanoribbons (GNR), often required for describing applications to practical devices, constitutes a heavy computational task, even in a simplified framework like that provided by discrete or nearest neighbour models. Scattering (S) matrix techniques, widely used for quantum transport in low dimensional systems and for the computation of electromagnetic fields, is shown here to provide a powerful formal platform for the analysis, and, in principle, the synthesis, of GNR multiport circuits. Periodic modes, solutions of GNR waveguides, are demonstrated to obey charge conservation and reciprocity constraints corresponding to unitary and symmetry properties of the S-matrix, under proper normalization conditions. We propose a systematic use of this approach to deal with problems such as scattering by lattice defects, the presence of external applied fields, crossing GNRs and T-junctions.

Influence of gestational age on the EDIN score: an observational study.

BACKGROUND AND AIM: Hospitalised neonates, particularly if preterm, may be exposed to prolonged pain. At present the only validated scale to assess prolonged pain in preterms is the EDIN (Echelle Douleur Inconfort Nouveau-Né) scale. Gestational age has been shown to influence the response of infants to acute pain but its potential effect in the setting of prolonged pain has not been investigated. The aim of the present study was to evaluate whether neonatal maturity as expressed by gestational age and/or postnatal age influences their expression of prolonged pain. METHODS: In a 1 year period, 84 neonates (gestational age 25-41 weeks), referred to the authors' neonatal intensive care unit were evaluated using the EDIN scale two to three times a day (1571 scores). The EDIN scores were categorised as indicative (>6) or not indicative (< or =6) of pain. Gestational age and postnatal age were included in a logistic regression analysis along with some painful situations and analgesic treatment to identify the impact on the EDIN scores. RESULTS: Logistic regression analysis showed that the EDIN scores were positively associated with gestational age (odds ratio 1.166; 95% CI 1.123 to 1.211). Postnatal age, sepsis and presence of respiratory support also influenced the EDIN score. CONCLUSIONS: Gestational age influences expression of prolonged pain. Content validity of the EDIN scale could be improved by adding categories for gestational age and attributing higher basal scores to less mature newborns.

Modelling of multi-wall CNT devices by self-consistent analysis of multichannel transport.

We present a generalization of the self-consistent analysis of carbon nanotube (CNT) field effect transistors (FETs) to the case of multi-wall/multi-band coherent carrier transport. The contribution to charge diffusion, due to different walls and sub-bands of a multi-wall (mw) CNT is shown to be non-negligible, especially for high applied external voltages and 'large' diameters. The transmission line formalism is used in order to solve the Schrödinger equation for carrier propagation, coupled to the Poisson equation describing the spatial voltage distribution throughout the device. We provide detailed numerical results for semiconducting mw-nanotubes of different diameters and lengths, such as current-voltage characteristics and frequency responses.

Optical and mechanical shrinkage effects in dye-doped photonic bandgap structures based on organic materials.

In this work we study the effects of the optical shrinkage in polymer and liquid crystal (LC) mixtures optimized for their use as active media in compact plastic laser devices. These mixtures are characterized by the presence of the rhodamine 6G as an active dye. Modifications in the reflection properties of the gratings as a function of the active dye concentration have been determined experimentally and a detailed theoretical simulation of the optical transmittance properties of these devices is provided. Moreover, the comparison between two different experimental approaches clarifies the contribution to the optical shrinkage due to the presence of the active dye. In principle this approach allows determining the linear mechanical shrinkage by separating the contribution to optical shrinkage due to photochemical transformations from that due to mechanical effects.

Characterisation and transferability of apple SSRs to two European pear F1 populations.

European pear (Pyrus communis L.) is among the important fruit species for which only few genetic studies have been carried out. Available evidence indicates that simple sequence repeats (SSR) are very useful as molecular markers because they are codominant, highly polymorphic, abundant and reproducible. The present paper reports more than 100 apple SSR markers in two populations of European pear; a total of 41 SSR markers were then positioned on a genetic linkage map of the cross 'Passe Crassane' x 'Harrow Sweet' and 31 in the map 'Abbe Fetel' x 'Max Red Bartlett'. Syntenic relationships between pear and apple maps have been considered for the chromosomes carrying two or more SSR markers. The alignment among the two maps supports the colinearity of the two genomes with respect both to identification and to orientation of the linkage groups.