Self-assessment of bone conduction hearing threshold using mobile audiometry: comparison with pure tone audiometry.

OBJECTIVE: The aim of the research was to evaluate the feasibility of measuring the bone conduction hearing threshold using self-administered mobile audiometry. DESIGN: A single-centre, closed, cross-over trial was carried out on patients from the ENT Department. A mobile-based, self-administered, audiologist-assisted assessment of the bone conduction hearing threshold was carried out by means of the open-access, freeware app Hearing Test using two types of bone conduction headphones: professional B71 bone transducer and commercially available AfterShokz Openmove open-ear headphones. STUDY SAMPLE: Seventy-seven ears. RESULTS: A test-retest examination revealed the lowest standard deviation for open-ear headphones at 3.33 dB (95% CI 2.92-3.79). When compared with pure tone audiometry, the intraclass correlations of 0.95 (95% CI 0.94-0.96) and 0.90 (95% CI 0.88-0.92) were obtained for the bone transducer and for the open-ear headphones, indicating excellent and good reliability, respectively. However, the regression slope of 0.67 was found for the air-bone gap when using open ear headphones, which was significantly different from 1 (p < 0.001). CONCLUSIONS: Open-ear headphones provide an alternative for estimating bone conduction once the air-bone gap has been adjusted by a factor of 1/0.6 7 ≅1.5. They demonstrate improved reproducibility over the bone transducer and are much easier to use with a mobile device. Trial Registration: Wroclaw Medical University, Science Support Centre, BW60/2020.

Effects of Application of Recycled Chicken Manure and Spent Mushroom Substrate on Organic Matter, Acidity, and Hydraulic Properties of Sandy Soils.

Soil organic matter is a key resource base for agriculture. However, its content in cultivated soils is low and often decreases. This study aimed at examining the effects of long-term application of chicken manure (CM) and spent mushroom substrate (SMS) on organic matter accumulation, acidity, and hydraulic properties of soil. Two podzol soils with sandy texture in Podlasie Region (Poland) were enriched with recycled CM (10 Mg ha-1) and SMS (20 Mg ha-1), respectively, every 1-2 years for 20 years. The application of CM and SMS increased soil organic matter content at the depths of 0-20, 20-40, and 40-60 cm, especially at 0-20 cm (by 102-201%). The initial soil pH increased in the CM- and SMS-amended soil by 1.7-2.0 units and 1.0-1.2 units, respectively. Soil bulk density at comparable depths increased and decreased following the addition of CM and SMS, respectively. The addition of CM increased field water capacity (at -100 hPa) in the range from 45.8 to 117.8% depending on the depth within the 0-60 cm layer. In the case of the SMS addition, the value of the parameter was in the range of 42.4-48.5% at two depths within 0-40 cm. Depending on the depth, CM reduced the content of transmission pores (>50 µm) in the range from 46.3 to 82.3% and increased the level of residual pores (<0.5 µm) by 91.0-198.6%. SMS increased the content of residual pores at the successive depths by 121.8, 251.0, and 30.3% and decreased or increased the content of transmission and storage pores. Additionally, it significantly reduced the saturated hydraulic conductivity at two depths within 0-40 cm. The fitted unsaturated hydraulic conductivity at two depths within the 0-40 cm layer increased and decreased in the CM- and SMS-amended soils, respectively. The results provide a novel insight into the application of recycled organic materials to sequester soil organic matter and improve crop productivity by increasing soil water retention capacity and decreasing acidity. This is of particular importance in the case of the studied low-productivity sandy acidic soils that have to be used in agriculture due to limited global land resources and rising food demand.

Linking Microbial Enzymatic Activities and Functional Diversity of Soil around Earthworm Burrows and Casts.

The aim of this work was to evaluate the effect of earthworms (Lumbricidae) on the enzymatic activity and microbial functional diversity in the burrow system [burrow wall (BW) 0-3 mm, transitional zone (TZ) 3-7 mm, bulk soil (BS) > 20 mm from the BW] and cast aggregates of a loess soil under a pear orchard. The dehydrogenase, ß-glucosidase, protease, alkaline phosphomonoesterase, and acid phosphomonoesterase enzymes were assessed using standard methods. The functional diversity (catabolic potential) was assessed using the Average Well Color Development and Richness Index following the community level physiological profiling from Biolog Eco Plates. All measurements were done using soil from each compartment immediately after in situ sampling in spring. The enzymatic activites including dehydrogenase, protease, ß-glucosidase and alkaline phosphomonoesterase were appreciably greater in the BW or casts than in BS and TZ. Conversely, acid phosphomonoesterase had the largest value in the BS. Average Well Color Development in both the TZ and the BS (0.98-0.94 A590 nm) were more than eight times higher than in the BWs and casts. The lowest richness index in the BS (15 utilized substrates) increased by 86-113% in all the other compartments. The PC1 in principal component analysis mainly differentiated the BWs and the TZ. Utilization of all substrate categories was the lowest in the BS. The PC2 differentiated the casts from the other compartments. The enhanced activity of a majority of the enzymes and increased microbial functional diversity in most earthworm-influenced compartments make the soils less vulnerable to degradation and thus increases the stability of ecologically relevant processes in the orchard ecosystem.