Spin-Hall effect and circular birefringence of a uniaxial crystal plate

The linear birefringence of uniaxial crystal plates is known since the 17th century, and it is widely used in numerous optical setups and devices. Here we demonstrate, both theoretically and experimentally, a fine lateral circular birefringence of such crystal plates. This effect is a novel example of the spin-Hall effect of light, i.e., a transverse spin-dependent shift of the paraxial light beam transmitted through the plate. The well-known linear birefringence and the new circular birefringence form an interesting analogy with the Goos-H\"anchen and Imbert-Fedorov beam shifts that appear in the light reflection at a dielectric interface. We report the experimental observation of the effect in a remarkably simple system of a tilted half-wave plate and polarizers using polarimetric and quantum-weak-measurement techniques for the beam-shift measurements. In view of great recent interest in spin-orbit interaction phenomena, our results could find applications in modern polarization optics and nano-photonics.Comment: 16 pages, 8 figures, to appear in Optic

Student Training in a University Setting Voice Clinic- How do we do it?

This presentation will discuss the challenges that clinical supervisors face when trying to balance efficient graduate student training and patient welfare in university voice clinics. We will propose a model in which we seek to balance the needs of the patient, student clinician, and clinical instructor

Les hémodialysés HVC sont-ils vraiment des patients difficiles à traiter?

L'hépatite C demeure la principale infection virale chez l'hémodialysé, dont la prise en charge thérapeutique ainsi que la gestion de ses effets secondaires restent difficiles. Il s'agit d'une étude rétrospective portant sur tous les patients atteints d'hépatite C chronique ayant une insuffisance rénale chronique sous hémodialyse, suivis au service de gastroentérologie au CHU Mohamed VI de Marrakech sur une période de Janvier 2004 à Décembre 2014. Sur un total de 355 cas d'hépatite virale C, 13 patients étaient hémodialysés (3,66%). Dix patients ont été traités, soit 76,94% des cas. Le traitement n'était pas indiqué chez 2 patients ayant une fibrose minime sans cytolyse. Il était contre indiqué chez une patiente multitarée. Deux malades ont eu une réponse virologique rapide et 5 une réponse virologique précoce. Le taux de réponse virologique soutenue était de 40%, 30% des patients étaient non répondeurs. Le traitement fut arrêté chez 2 patientes pour effets secondaires sévères. Un seul patient a été candidat à une transplantation rénale. En analyse multivariée, la réponse virologique soutenue a été significativement associée à certains facteurs prédictifs de bonne réponse thérapeutique : Age jeune ≤40 ans (P=0,0057), fibrose minime F1-F2 (P=0,03), génotype non 1 (P=0,0064), charge virale préthérapeutique <800000 UI/ml (P=0,013), et l'absence d'arrêt thérapeutique (P=0,028). La gestion efficace des effets secondaires du traitement de HVC permet d'obtenir chez l'hémodialysé un taux de réponse virologique soutenue avoisinant celui de la population générale

Formulasi Dan Karakteristik Fisik Sediaan Plester Hidrogel Ekstrak Daun Ciplukan (Physalis angulata L.) Dan Batang Kayu Manis (Cinnamomum burmannii)

Diabetes mellitus is a degenerative disease caused by the damage of beta pancreatic cells. This caused many complication such as diabetic ulcer which left untreated can cause an open wound hard to heal thereby reducing the quality of life. Treatment of diabetic ulcer despite using antidiabetic also using an antibiotic therapy like Mupirocin. In its development, the use of natural ingredients is known to be used as adjuvant therapy for diabetic ulcer such as Ciplukan leaves and Kayu Manis bark. Both of the plant contain phytochemical compound like sinamaldehid, tannin, polyphenol and flavonoid which can work as wound healer. To increase its efficacy then Ciplukan leaves and Kayu Manis bark were formulated as hydrogel patch. Hydrogel patch are known has advantages like better penetration, hygienic and easy to administered Ciplukan (Physalis angulata L.) leaves and Kayu Manis (Cinnamomum burmannii) Bark extracted with maceration technique. The extracts then made into matrix type hydrogel patch with 10% HPMC and 5% PVA as backing patch. The backing patch and extract then placed on a square cast and dried under room temperature for 24 hours. The hydrogel patch then evaluated for physical characteristic including organoleptic aspect, weight uniformity, moisture content and pH. The results showed that Ciplukan leaves and Kayu Manis Bark hydrogel patch have a semi solid consistency, transparent greenish color and distinctive smell. The average pH is 5,5 and have average weight around 1,18 grams. The moisture contens of hydrogel patch is 2,42%. The Ciplukan leaves and Kayu Manis bark is able to formulated into hydrogel patch. The hydrogel patch is showing good appearance and having good properties as topical dosage form. The pH of the hydrogel patch is suitable with pH of the skin and have no intention to irritate the skin. Hydrogel patch also giving a cooling sensations in wound area thus increase patients convenience and acceptability.  Keywords: Diabetes mellitus, extract, drug delivery system, hydrogel patch, adjuvant therap

Cepstral peak prominence: a comprehensive analysis

An analytical study of cepstral peak prominence (CPP) is presented, intended to provide an insight into its meaning and relation with voice perturbation parameters. To carry out this analysis, a parametric approach is adopted in which voice production is modelled using the traditional source-filter model and the first cepstral peak is assumed to have Gaussian shape. It is concluded that the meaning of CPP is very similar to that of the first rahmonic and some insights are provided on its dependence with fundamental frequency and vocal tract resonances. It is further shown that CPP integrates measures of voice waveform and periodicity perturbations, be them either amplitude, frequency or noise

Gap-induced reductions of evoked potentials in the auditory cortex: a possible objective marker for the presence of tinnitus in animals

Animal models of tinnitus are essential for determining the underlying mechanisms and testing pharmacotherapies. However, there is doubt over the validity of current behavioural methods for detecting tinnitus. Here, we applied a stimulus paradigm widely used in a behavioural test (gap-induced inhibition of the acoustic startle reflex GPIAS) while recording from the auditory cortex, and showed neural response changes that mirror those found in the behavioural tests. We implanted guinea pigs (GPs) with electrocorticographic (ECoG) arrays and recorded baseline auditory cortical responses to a startling stimulus. When a gap was inserted in otherwise continuous background noise prior to the startling stimulus, there was a clear reduction in the subsequent evoked response (termed gap-induced reductions in evoked potentials; GIREP), suggestive of a neural analogue of the GPIAS test. We then unilaterally exposed guinea pigs to narrowband noise (left ear; 8-10 kHz; 1 hour) at one of two different sound levels - either 105 dB SPL or 120 dB SPL – and recorded the same responses seven-to-ten weeks following the noise exposure. Significant deficits in GIREP were observed for all areas of the auditory cortex (AC) in the 120 dB-exposed GPs, but not in the 105 dB-exposed GPs. These deficits could not simply be accounted for by changes in response amplitudes. Furthermore, in the contralateral (right) caudal AC we observed a significant increase in evoked potential amplitudes across narrowband background frequencies in both 105 dB and 120 dB-exposed GPs. Taken in the context of the large body of literature that has used the behavioural test as a demonstration of the presence of tinnitus, these results are suggestive of objective neural correlates of the presence of noise-induced tinnitus and hyperacusis

Frailty Syndrome, Cognition, and Dysphonia in the Elderly

Purpose. The purpose of the current study is to determine the relation of frailty syndrome to acoustic measures of voice quality and voice-related handicap. Methods. Seventy-three adults (52 community-dwelling participants and 21 assisted living residents) age 60 and older completed frailty screening, acoustic assessment, cognitive screening, and the Voice Handicap Index-10 (VHI-10). Factor analysis was used to consolidate acoustic measures. Statistical analysis included multiple regression, analysis of variance, and Tukey post-hoc tests with alfa of 0.05. Results. Montreal Cognitive Assessment (MoCA) and exhaustion explained 28% of the variance in VHI-10. MoCA and sex explained 27% of the variance in factor 1 (spectral ratio), age and MoCA explained 13% of the variance in factor 2 (cepstral peak prominence for speech), and slowness explained 10% of the variance in factor 3 (cepstral peak prominence for sustained /a/). There were statistically significant differences in two measures across frailty groups: VHI-10 and MoCA. Acoustic factor scores did not differ significantly among frailty groups (P > 0.05). Conclusions. Voice-related handicap and cognitive status differed among robust and frail older adults, yet vocal function measures did not. The components of frailty most related to VHI-10 were exhaustion and weight loss rather than slowness, weakness, or inactivity. Based on these findings, routine screening of physical frailty and cognition are recommended as part of a complete voice evaluation for older adults.12 month embargo; published online: 25 July 2018This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]