The Lombard effect in singing humpback whales: Source levels increase as ambient ocean noise levels increase.

Many animals increase the intensity of their vocalizations in increased noise. This response is known as the Lombard effect. While some previous studies about cetaceans report a 1 dB increase in the source level (SL) for every dB increase in the background noise level (NL), more recent data have not supported this compensation ability. The purpose of this study was to calculate the SLs of humpback whale song units recorded off Hawaii and test for a relationship between these SLs and background NLs. Opportunistic recordings during 2012-2017 were used to detect and track 524 humpback whale encounters comprised of 83 974 units on the U.S. Navy's Pacific Missile Range Facility hydrophones. Received levels were added to their estimated transmission losses to calculate SLs. Humpback whale song units had a median SL of 173 dB re 1 µPa at 1 m, and SLs increased by 0.53 dB/1 dB increase in background NLs. These changes occurred in real time on hourly and daily time scales. Increases in ambient noise could reduce male humpback whale communication space in the important breeding area off Hawaii. Since these vocalization changes may be dependent on location or behavioral state, more work is needed at other locations and with other species.

Lombard effect: Minke whale boing call source levels vary with natural variations in ocean noise.

Minke whales were acoustically detected, localized, and tracked on the U.S. Navy's Pacific Missile Range Facility from 2012 to 2017. Animal source levels (SLs) were estimated by adding transmission loss estimates to measured received levels of 42 159 individual minke whale boings. Minke whales off Hawaii exhibited the Lombard effect in that they increased their boing call intensity in increased background noise. Minke whales also decreased the variance of the boing call SL in higher background noise levels. Although the whales partially compensated for increasing background noise, they were unable or unwilling to increase their SLs by the same amount as the background noise. As oceans become louder, this reduction in communication space could negatively impact the health of minke whale populations. The findings in this study also have important implications for acoustic animal density studies, which may use SL to estimate probability of detection.

Exposure factors associated with chronic beryllium disease development in Beryllium BioBank participants.

OBJECTIVE: To assess the importance of occupational history for beryllium-exposed workers. METHODS: Beryllium BioBank data were analyzed for 532 subjects in the following three groups: beryllium-exposed, beryllium-sensitized, and chronic beryllium disease. Predictor variables were several questionnaire-derived exposure indices. RESULTS: Cumulative exposure estimated from a standardized interview contributes to differentiating beryllium-exposed from chronic beryllium disease. The likelihood of progression from sensitization to disease was associated with peak-level weighted exposure hours. CONCLUSIONS: Selecting workers for extensive diagnostic testing should consider each worker's duration and characteristics of exposure. The intensity and total hours of exposure should be evaluated rather than relying on only the total years.

Beryllium BioBank: 2. Lymphocyte proliferation testing.

OBJECTIVE: To incrementally improve the use of beryllium lymphocyte proliferation test (LPT) results. METHODS: Beryllium BioBank data were analyzed for 532 subjects in three groups: beryllium-exposed, sensitized, or chronic beryllium disease. Predictor variables were LPT stimulation index (SI) at the date of the earliest available data and at the study entry date. RESULTS: Cross-sectionally, LPT SI magnitude does not distinguish among the three groups. The likelihood of progression from sensitization to disease is associated with the absolute value of SI, but LPT SI interpreted by traditional cut point criteria was not predictive. CONCLUSIONS: Updating the criteria for interpreting beryllium LPT data should be considered. Prediction of progression to chronic beryllium disease may be improved by changing the cut point for interpretation or by using the SI as a continuous variable.

Professional activities of experienced occupational health nurses.

Occupational health nurses have diverse backgrounds and their practices require the ability to perform unique professional tasks. This study empirically evaluated their activities and skills using a web-based log system to describe activities at 15 specific sampled times. A national sample of 128 occupational health nurses provided 1,893 activity logs revealing occupational health nurses use both clinical and management skills on a regular basis; indirect client care is as common as direct "hands-on" client care. Most occupational health nurses are directly paid by their employer and activities serve to benefit both individual workers and their employers. Occupational health nurses have specific knowledge and skills in addition to general nursing competencies. Understanding the actual work of occupational health nurses is necessary to align training, certification, and competency maintenance systems such as continuing education with the unique skills used in actual practice activities.

Comparison of three respirator user training methods.

OBJECTIVE: This study addresses methods for training respirator users, particularly when occupational health professionals are not immediately available. METHODS: A randomized trial compared three training methods-printed brochure, video, and computer-based training-for two respirator types (filtering facepiece and a dual-cartridge half facemask). Quantitative fit testing (PortaCount) measured the effectiveness of training. The study included 226 subjects. RESULTS: For both respirator types, video was significantly superior to either print or computer-based training methods. Conclusions were consistent, whether determined by average fit factor (analysis of variance), log-transformed fit factors, or the number of users in the lowest quartile of achieved fit. CONCLUSIONS: Video training for proper respirator use can be effective when direct training from an occupational health professional is unavailable. These methods are particularly relevant to "rapid rollout" situations, such as natural disasters, epidemics, or bioterrorism concerns.

Component analysis of respirator user training.

Respirators must be properly used to be effective. In an experimental protocol, 145 subjects were trained and then observed donning and doffing respirators. Filtering facepiece and dual cartridge half face mask types were studied. Subjects were then tested for knowledge and for proper performance using video recording analysis. Knowledge tests showed adequate learning, but performance was often poor. Inspection, strap tension (half mask), seal checking, and avoiding mask contact during doffing were particularly problematic. Mask positioning was generally well done. Correlation between knowledge and performance for specific items was generally poor, although there was a weak correlation between overall knowledge and overall performance (rho = 0.32) for the half mask users. Actual unprompted performance as well as knowledge and fit-testing should be assessed for user certification. Respirator design approval should consider users' ability to learn proper technique.