The Impact of an Accurate Vertical Localization with HRTFs on Short Explorations of Immersive Virtual Reality Scenarios

Achieving a full 3D auditory experience with head-related transfer functions (HRTFs) is still one of the main challenges of spatial audio rendering. HRTFs capture the listener's acoustic effects and personal perception, allowing immersion in virtual reality (VR) applications. This paper aims to investigate the connection between listener sensitivity in vertical localization cues and experienced presence, spatial audio quality, and attention. Two VR experiments with head-mounted display (HMD) and animated visual avatar are proposed: (i) a screening test aiming to evaluate the participants' localization performance with HRTFs for a non-visible spatialized audio source, and (ii) a 2 minute free exploration of a VR scene with five audiovisual sources in a both non-spatialized (2D stereo panning) and spatialized (free-field HRTF rendering) listening conditions. The screening test allows a distinction between good and bad localizers. The second one shows that no biases are introduced in the quality of the experience (QoE) due to different audio rendering methods; more interestingly, good localizers perceive a lower audio latency and they are less involved in the visual aspects

Lifestyle and socio-demographic factors associated with high-risk HPV infection in UK women

The world age-standardised prevalence of high-risk HPV (hrHPV) infection among 5038 UK women aged 20–59 years, with a low-grade smear during 1999–2002, assessed for eligibility for TOMBOLA (Trial Of Management of Borderline and Other Low-grade Abnormal smears) was 34.2%. High-risk HPV prevalence decreased with increasing age, from 61% at ages 20–24 years to 14–15% in those over 50 years. The age-standardised prevalence was 15.1, 30.7 and 52.7%, respectively, in women with a current normal, borderline nuclear abnormalities (BNA) and mild smear. In overall multivariate analyses, tertiary education, previous pregnancy and childbirth were associated with reduced hrHPV infection risk. Risk of infection was increased in non-white women, women not married/cohabiting, hormonal contraceptives users and current smokers. In stratified analyses, current smear status and age remained associated with hrHPV infection. Data of this type are relevant to the debate on human papillomavirus (HPV) testing in screening and development of HPV vaccination programmes

Sex- and age-dependent association of SLC11A1 polymorphisms with tuberculosis in Chinese: a case control study

BACKGROUND: Host genetic factors are important determinants in tuberculosis (TB). The SLC11A1 (or NRAMP1) gene has been studied extensively for genetic association with TB, but with inconsistent findings. In addition, no study has yet looked into the effect of sex and age on the relationship between SLC11A1 polymorphisms and TB. METHODS: A case-control study was conducted. In total, 278 pulmonary TB patients and 282 sex- and age-matched controls without TB were recruited. All subjects were ethnic Chinese. On the basis of linkage disequilibrium pattern, three genetic markers from SLC11A1 and one from the nearby IL8RB locus were selected and examined for association with TB susceptibility. These markers were genotyped using single strand conformation polymorphism analysis or fragment analysis of amplified products. RESULTS: Statistically significant differences in allele (P = 0.0165, OR = 1.51) and genotype (P = 0.0163, OR = 1.59) frequencies of the linked markers SLC6a/b (classically called D543N and 3'UTR) of the SLC11A1 locus were found between patients and controls. With stratification by sex, positive associations were identified in the female group for both allele (P = 0.0049, OR = 2.54) and genotype (P = 0.0075, OR = 2.74) frequencies. With stratification by age, positive associations were demonstrated in the young age group (age ≤65 years) for both allele (P = 0.0047, OR = 2.52) and genotype (P = 0.0031, OR = 2.92) frequencies. All positive findings remained significant even after correction for multiple comparisons. No significant differences were noted in either the male group or the older age group. No significant differences were found for the other markers (one SLC11A1 marker and one IL8RB marker) either. CONCLUSION: This study confirmed the association between SLC11A1 and TB susceptibility and demonstrated for the first time that the association was restricted to females and the young age group

Virtual reality exploration with different head-related transfer functions

One of the main challenges of spatial audio rendering in headphones is the crucial work behind the personalization of the so-called head-related transfer functions (HRTFs). HRTFs capture the listener's acoustic effects allowing a personal perception of immersion in virtual reality context. This paper aims to investigate the possible benefits of personalized HRTFs that were individually selected based on anthropometric data (pinnae shapes). Personalized audio rendering was compared to a generic HRTF and a stereo sound condition. Two studies were performed; the first study consisted of a screening test aiming to evaluate the participants' localization performance with HRTFs for a non-visible spatialized audio source. The second experiment allowed the participants to freely explore a VR scene with five audiovisual sources for two minutes each, with both HRTF and stereo conditions. A questionnaire with items for spatial audio quality, presence and attention was used for the evaluation. Results indicate that audio rendering methods made no difference on responses to the questionnaire in the two minutes of a free exploration

In-process spectroscopic detection of chromium loss during Directed Energy Deposition of alloy 718

In this work, a fast optical spectrometer was used to monitor the Directed Energy Deposition (DED) process, during the deposition of Alloy 718 samples with different laser power, thus different energy inputs into the material. Spectroscopic measurements revealed the presence of excited Cr I atoms in the plasma plume. The presence was more apparent for the samples characterized by higher energy input. The Cr depletion from these samples was confirmed by lower Cr content detected by Energy-Dispersive X-ray Spectroscopy (EDS) analysis. The samples were also characterized by higher oxidation and high-temperature corrosion rates in comparison to the samples produced with low energy input. These results prove the applicability of an optical emission spectroscopic system for monitoring DED to identify process conditions leading to compositional changes and variation in the quality of the built material