Background<br />In contrast to most of the world, the cervical cancer screening programme continued in Denmark throughout the COVID-19 pandemic. We examined the cervical cancer screening participation during the pandemic in Denmark.<br /><br />Methods<br />We included all women aged 23-64 years old invited to participate in cervical cancer screening from 2015-2021 as registered in the Cervical Cancer Screening Database combined with population-wide registries. Using a generalised linear model, we estimated prevalence ratios (PR) and 95% confidence intervals (CI) of cervical cancer screening participation within 90, 180 and 365 days since invitation during the pandemic in comparison with the previous years adjusting for age, year and month of invitation.<br /><br />Results<br />Altogether, 2,220,000 invited women (in 1,466,353 individuals) were included in the study. Before the pandemic, 36% of invited women participated in screening within 90 days, 54% participated within 180 days and 65% participated within 365 days. At the start of the pandemic, participation in cervical cancer screening within 90 days was lower (pre-lockdown PR=0.58; 95% CI: 0.56-0.59 and 1st lockdown PR=0.76; 95% CI: 0.75-0.77) compared with the previous years. A reduction in participation within 180 days was also seen during pre-lockdown (PR=0.89; 95% CI: 0.88-0.90) and 1st lockdown (PR=0.92; 95% CI: 0.91-0.93). Allowing for 365 days to participation, only a slight reduction (3%) in participation was seen with slightly lower participation in some groups (immigrants, low education and low income).<br /><br />Conclusions<br />The overall participation in cervical cancer screening was reduced during the early phase of the pandemic. However, the decline almost diminished with longer follow-up time.<br /><br />Funding<br />The study was funded by the Danish Cancer Society Scientific Committee (grant number R321- A17417) and the Danish regions.

Binaural synthesis offers a method for creating a truly immersive three-dimensional auditory environment. The sound output is produced by convolving a sound input with sets of head-related transfer functions (HRTFs). The result is a set of two signals typically reproduced by means of headphones, and the technique is therefore well suited for systems with limited hardware for sound reproduction, such as most multimedia systems. In the present paper, HRTFs are presented in the time and frequency domains, and are commented upon in relation to their application for binaural synthesis using digital signal processing. Results obtained from experiments conducted at the Acoustics Laboratory at Aalborg University in Denmark are reviewed, giving hints for the selection of filter lengths, update rate, and spatial resolution for dynamic environments.

Twelve artificial heads, of which one was designed at the authors’ laboratory, were evaluated in a localization test. The localization performance was compared in two situations: First, the subjects localized sound sources in a real sound field, then the localization test was repeated with artificial head recordings of the same sound field. The sounds to be localized were loudspeaker reproductions of female speech at natural level, from 19 different positions in a standard listening room. The artificial head recordings were reproduced by carefully equalized headphones. Results from eight of the heads showed an increased number of localization errors compared to real-life performance. The directions in the median plane were most often confused, not only with nearby directions, but also with directions further away. The number of errors was significantly higher than what can be obtained with recordings from a carefully selected human head. Results from the last four heads, including the one from the authors’ laboratory, were not available at the time of abstract submission.

The localization performance was studied when subjects listened (1) to a real sound field and (2) to binaural recordings of the same sound field, made (a) in their own ears, and (b) in the ears of other subjects. The sounds to be localized were loudspeaker reproductions of female speech at natural level, from 19 different positions in a standard listening room. The binaural recordings were reproduced by carefully equalized headphones. With individual recordings the performance was preserved compared to real life, whereas nonindividual recordings resulted in significantly more errors for sound sources in the median plane. Errors were seen in terms of confusion not only between nearby directions, but also between directions further away, such as between sound sources in front and behind the subject. However, nonindividual recordings made in the ears of a carefully selected ‘‘typical’’ subject resulted in a performance much closer to the real-life performance, although still inferior.

Earlier studies have shown that a carefully selected human substituting an artificial head can minimize the amount of localization errors for a group of people in a listening experiment, thus indicating that a set of head-related transfer functions (HRTFs) can be found, which to some extent fits a population. This study aims at exploring ways of designing such general sets of HRTFs suitable for larger populations. An effort is put into considering the importance of, e.g., different frequency regions of the transfer functions in order to focus on the most general characteristics and avoid focusing attention on highly individual features. The physical origin of the different parts of the HRTFs will be taken into consideration, and HRTF design methods using parameters derived through signal analysis will be studied.