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The success of visual-based localization requires the image features to be sufficiently captured in well-exposed images and reliably tracked among image sequences. In this paper, a learning-based exposure strategy algorithm is developed to improve the performance of visual odometry or simultaneous localization and mapping in scenes with sudden illumination changes and high dynamic range (HDR). The exposure value is predicted by optimizing a novel image information metric, which is calculated based on a multi-scale image histogram. Experimental observations show that the proposed metric is highly related to the localization performance, and achieves better localization accuracy when compared to other state-of-the-art metrics. Using this novel metric, the exposure control network is designed to predict the exposure value for the next image given a sequence of recently captured images as inputs. For different application scenarios, alternative network frameworks are proposed with the options to include an optimization module providing improved exposure values for feedback learning, but with additional computation complexity. The approach is light-weight for real-time video applications and the images captured using the predicted exposure values are well-exposed with better detected and matched features in a variety of challenging HDR scenes. Code will be available in . [ABSTRACT FROM AUTHOR]

Objectives. The unique properties of nanomaterials have turned them into an emerging threat for humans and the environment. This study therefore aimed to review exposure control measures proposed for nanomaterial-involved activities. Methods. This study is based on the published guidelines of different organizations on safe handling of nanomaterials. The search for documents was provided using the keywords 'Exposure controls', 'Good practices', 'Working safely', 'Safe practices', 'Handling safely', 'Safety guide' and 'Safety and health', combined with 'Nanomaterials', 'Nanotechnology' and 'Nanoparticles' on different databases and websites. Results. Thirty-one guidelines from 27 organizations were included. Most of the guidelines recommended engineering controls, administrative controls and personal protective equipment (PPE). Changing the physical form of nanomaterials or the process, using prevention through design (PtD) and using green chemistry principals were other suggestions to reduce exposure to nanomaterials. Conclusions. Considering the difficulty of implementation and case specificity of the solutions of the first two priorities of the hierarchy of controls (elimination and substitution), the emphasis of the guidelines on the next three priorities for controlling exposure to nanomaterials is understood. The type and method of using PPE and engineering controls should be resolved by referring to cutting-edge articles. [ABSTRACT FROM AUTHOR]

Objective: Noise exposure limit is one of the critical measures to prevent noise-induced hearing loss (NIHL). This review aimed to review the progress and recommendations for developing occupational exposure limits (OELs) for workplace noise. Methods: A systematic review was used. Thirty-eight national or international organizations' noise exposure standards (including OEL) and laws, regulations, and guidelines for noise exposure control were analyzed. Articles on recommendations for revising noise OEL standards between 2000 and 2023 were selected. Results: The definition of different noise types (especially for non-steady and impulsive noise) varied worldwide, and the used 8-h OEL varied from 80 to 90 dB(A). Maximum sound pressure level (Lmax) and noise dose for industrial noise and peak sound pressure level (Lpeak) for impulsive noise have been incorporated into the OELs. Countries developed noise risk management measures based on OELs, action levels (ALs), and exposure risk ratio or classification. The risk of co-exposure to noise and ototoxic organic substances and the effects of noise on susceptible populations were concerns in EU country standards. Scholars suggested revising the existing noise exposure standards based on noise's temporal structure (expressed by kurtosis), effective noise level, impulsive noise OEL, action level, and key factors of risk assessment. Conclusions: Indicators such as Lmax, noise dose, Lpeak, and action level can be incorporated into noise OELs. Developing noise OEL standards should consider the co-exposure of noise and ototoxic substances, HPD's noise attenuation, susceptible groups, and noise's temporal structure.

Objective: This survey aimed to investigate exposure to welding fume in Australian workplaces and the use of protective and control measures among workers. Methods: Data were collected via a cross-sectional online survey of workers and employers involved in welding in Australia. Survey questions focused on the determinants of exposure to welding fume, welding experience and qualifications, and use of control measures. Results: There were 634 respondents to the survey across Australia of whom 577 (91%) were assessed as being exposed to welding fume, most at high levels. Welders undertook a wide range of types of welding, and higher-risk welding such as in confined and restricted spaces was common. Most workplaces did not have any form of mechanical ventilation, and use of air-supplied respiratory protection was poor even when ventilation was not used. Conclusion: Welders in Australia are exposed to several carcinogens, particularly welding fume, hexavalent chromium (CrVI) and nickel, and the use of control measures is sub-optimal. Implications for Public Health: Higher-order controls are the best way to reduce exposure to carcinogens in the workplace. The lack of use of these controls by Australian welders is concerning and needs to be a focus of attention by regulators and companies.

Osimertinib (Tagrisso®) has an inhibitory effect on epidermal growth factor receptor (EGFR) tyrosine kinase and it has been used for the treatment of non-small cell lung cancer. A simple suspension method may be considered if taking tablets is difficult due to problems such as dysphagia; however, few studies have applied this method to osimertinib. Herein, we have report a case of non-small cell lung cancer in which the patient's family could continue administering an osimertinib suspension simply through a tube at home. Osimertinib was initiated for the patient, but dysphagia hindered drug ingestion. Consequently, a ward pharmacist suggested tube administration of a simple suspension of osimertinib to the attending physician. The ward pharmacist also provided a nurse information on exposure control for this drug administration method. Before hospital discharge, and the nurse instructed the patient's family on simple suspension administration and exposure control methods. The ward pharmacist also informed a pharmacist at the patient’s local pharmacy on medication management. The patient's family continued to administer osimertinib suspension through a tube at home, and the brain metastases visibly reduced. [ABSTRACT FROM AUTHOR]

Task-based respirable crystalline silica (RCS) exposure monitoring data was collected from construction work sites across 3 Canadian provinces: Alberta, British Columbia (BC), and Manitoba. In total 373 RCS samples were obtained from 70 worksites across 44 companies. Sampling was conducted between May 2015 and August 2020. The overall geometric mean (GM) RCS exposure was 0.045 mg/m3 (geometric standard deviation, GSD = 6.8). Alberta had the highest average exposure and the highest variability with GM of 0.060 mg/m3 (GSD = 9.3), the GM in BC was 0.044 (GSD = 4.3), and in Manitoba the GM was 0.033 (GSD = 7.0). A multivariable model was built using forward stepwise linear regression modeling. Province, task type, work environment (indoor vs. outdoor), construction material, sampling duration, and engineering control use were all statistically significant predictors of exposure level in partial F -tests (P < 0.05). Overall, the model explained 42% of the RCS concentration variability. Task type contributed most to the model's explanatory power. The task type with highest average exposure levels was demolition (GM 0.30 mg/m3, GSD 0.49). Breaking (GM 0.16 mg/m3, GSD 8.4) and grinding (GM 0.081 m/m3, GSD 7.4) also had high-exposure levels. Working outdoors was associated with exposure levels 39% lower than indoors. Exposure control measures such as local exhaust ventilation and wetting were also associated with lower exposure levels. Among construction materials, Cement, sand, and stone were associated with higher RCS exposure levels relative to the reference material, concrete. The results of this study indicate that workers in western Canada remain exposed to RCS at levels that exceed the health-based American Congress for Governmental Industrial Hygienists Threshold Limit Value of 0.025 mg/m3. Although there were some differences in exposure levels between the provinces, the determinants of exposure were similar in all 3. The overall GM RCS exposure was 0.045 mg/m3 (geometric standard deviation, GSD = 6.8). Alberta had the highest average exposure and the highest variability with GM of 0.060 mg/m3 (GSD = 9.3), the GM in BC was 0.044 (GSD = 4.3), and in Manitoba the GM was 0.033 (GSD = 7.0). [ABSTRACT FROM AUTHOR]

Objectives To explore the value of dual-energy computed tomography (DE-CT) angiography in diagnosis of arteriogenic erectile dysfunction (ED) patients and feasibility of new scanning area that excludes the testis.Materials and methods Ninety-three patients suspected of suffering arterial ED and 40 health volunteers underwent penile duplex Doppler ultrasound and DE-CT angiography (DE-CTA). The scanning range of DE-CTA covered whole arterial system of pelvis and testis was excluded. Two blinded investigators independently evaluated the arterial system that supplies the penis.Results Finally, 1596 segments were evaluated and 470 segments were judged to be abnormal. The distribution was: 2 (0.4%) in common iliac artery, 7 (1.5%) in internal iliac artery, 82 (17.5%) in internal pudendal artery, 89 (18.9%) in penile artery, 120 (25.5%) in dorsal artery, and 170 (36.2%) in cavernosal artery. The specificity, sensitivity, positive predictive value, and negative predictive value of DE-CTA in diagnostic were 86.02%, 87.50%, 94.12%, and 72.92%. Besides, the new scan area allowed for effective evaluation of the arteries while excluding the testis.Conclusion DE-CTA can provide unbiased, safe evaluation of the vascular status of the penile bed in patients with ED.

Models of the human body representing digital twins of patients have attracted increasing interest in clinical research for the delivery of personalized diagnoses and treatments to patients. For example, noninvasive cardiac imaging models are used to localize the origin of cardiac arrhythmias and myocardial infarctions. The precise knowledge of a few hundred electrocardiogram (ECG) electrode positions is essential for their diagnostic value. Smaller positional errors are obtained when extracting the sensor positions, along with the anatomical information, for example, from X-ray Computed Tomography (CT) slices. Alternatively, the amount of ionizing radiation the patient is exposed to can be reduced by manually pointing a magnetic digitizer probe one by one to each sensor. An experienced user requires at least 15 min. to perform a precise measurement. Therefore, a 3D depth-sensing camera system was developed that can be operated under adverse lighting conditions and limited space, as encountered in clinical settings. The camera was used to record the positions of 67 electrodes attached to a patient's chest. These deviate, on average, by 2.0 mm ± 1.5 mm from manually placed markers on the individual 3D views. This demonstrates that the system provides reasonable positional precision even when operated within clinical environments. [ABSTRACT FROM AUTHOR]

Computerized classification testing (CCT) commonly chooses items maximizing information at the cut score, which yields the most information for decision‐making. However, a corollary problem is that all examinees will be given the same set of items, resulting in high test overlap rate and unbalanced item bank usage, which threatens test security. Moreover, another pivotal issue for CCT is time control. Since both the extremely long response time (RT) and large RT variability across examinees intensify time‐induced anxiety, it is crucial to reduce the number of examinees exceeding the time limitation and the differences between examinees' test‐taking times. To satisfy these practical needs, this paper proposes the novel idea of stage adaptiveness to tailor the item selection process to the decision‐making requirement in each step and generate fresh insight into the existing response time selection method. Results indicate that a balanced item usage as well as short and stable test times across examinees can be achieved via the new methods. [ABSTRACT FROM AUTHOR]

Digital image correlation (DIC) is widely used in material experiments such as ores; the quality of a speckle image directly affects the accuracy of the DIC calculation. This study aims to acquire high-quality speckle pattern images and improve the calculation accuracy and stability. A gradient-based image quality metric was selected to evaluate the image quality, and its validity was verified by a rigid body experiment and a numerical experiment. Based on the maximum image quality metric, an automatic exposure control algorithm and the control procedure were proposed to obtain the optimal exposure time. Finally, nine sets of images with different poses and illuminations were captured, and displacement and strain fields were calculated at the fixed exposure time and the optimized exposure time. The results of the rigid-body motion experiment show that the calculated data at the optimized exposure time is smoother and less noisy, and the error is smaller, which verifies the effectiveness of the exposure control procedure and its algorithm and improves the accuracy and stability of DIC calculation. [ABSTRACT FROM AUTHOR]

This study was the first to determine the effectiveness of radon concentration measurement in water using the degassing method as a screening method based on the liquid scintillation counter method. The degassing method used two radon monitors (AlphaGUARD and RAD7) and two monitor-attached degassing devices (AquaKIT and RAD H2O). These were effective screening methods based on the WHO guideline value of 100 Bq L−1. The screening values confirmed that a combination of the AlphaGUARD and AquaKIT was preferred. The results are useful for radon measurement for exposure control in drinking water and environmental in-situ field measurement. [ABSTRACT FROM AUTHOR]

To explore the value of dual-energy computed tomography (DE-CT) angiography in diagnosis of arteriogenic erectile dysfunction (ED) patients and feasibility of new scanning area that excludes the testis. Ninety-three patients suspected of suffering arterial ED and 40 health volunteers underwent penile duplex Doppler ultrasound and DE-CT angiography (DE-CTA). The scanning range of DE-CTA covered whole arterial system of pelvis and testis was excluded. Two blinded investigators independently evaluated the arterial system that supplies the penis. Finally, 1596 segments were evaluated and 470 segments were judged to be abnormal. The distribution was: 2 (0.4%) in common iliac artery, 7 (1.5%) in internal iliac artery, 82 (17.5%) in internal pudendal artery, 89 (18.9%) in penile artery, 120 (25.5%) in dorsal artery, and 170 (36.2%) in cavernosal artery. The specificity, sensitivity, positive predictive value, and negative predictive value of DE-CTA in diagnostic were 86.02%, 87.50%, 94.12%, and 72.92%. Besides, the new scan area allowed for effective evaluation of the arteries while excluding the testis. DE-CTA can provide unbiased, safe evaluation of the vascular status of the penile bed in patients with ED. [ABSTRACT FROM AUTHOR]

Models of the human body representing digital twins of patients have attracted increasing interest in clinical research for the delivery of personalized diagnoses and treatments to patients. For example, noninvasive cardiac imaging models are used to localize the origin of cardiac arrhythmias and myocardial infarctions. The precise knowledge of a few hundred electrocardiogram (ECG) electrode positions is essential for their diagnostic value. Smaller positional errors are obtained when extracting the sensor positions, along with the anatomical information, for example, from X-ray Computed Tomography (CT) slices. Alternatively, the amount of ionizing radiation the patient is exposed to can be reduced by manually pointing a magnetic digitizer probe one by one to each sensor. An experienced user requires at least 15 min. to perform a precise measurement. Therefore, a 3D depth-sensing camera system was developed that can be operated under adverse lighting conditions and limited space, as encountered in clinical settings. The camera was used to record the positions of 67 electrodes attached to a patient’s chest. These deviate, on average, by 2.0 mm ±1.5 mm from manually placed markers on the individual 3D views. This demonstrates that the system provides reasonable positional precision even when operated within clinical environments.

Objective: Noise exposure limit is one of the critical measures to prevent noise-induced hearing loss (NIHL). This review aimed to review the progress and recommendations for developing occupational exposure limits (OELs) for workplace noise., Methods: A systematic review was used. Thirty-eight national or international organizations' noise exposure standards (including OEL) and laws, regulations, and guidelines for noise exposure control were analyzed. Articles on recommendations for revising noise OEL standards between 2000 and 2023 were selected., Results: The definition of different noise types (especially for non-steady and impulsive noise) varied worldwide, and the used 8-h OEL varied from 80 to 90 dB(A). Maximum sound pressure level (L max ) and noise dose for industrial noise and peak sound pressure level (L peak ) for impulsive noise have been incorporated into the OELs. Countries developed noise risk management measures based on OELs, action levels (ALs), and exposure risk ratio or classification. The risk of co-exposure to noise and ototoxic organic substances and the effects of noise on susceptible populations were concerns in EU country standards. Scholars suggested revising the existing noise exposure standards based on noise's temporal structure (expressed by kurtosis), effective noise level, impulsive noise OEL, action level, and key factors of risk assessment., Conclusions: Indicators such as L max , noise dose, L peak , and action level can be incorporated into noise OELs. Developing noise OEL standards should consider the co-exposure of noise and ototoxic substances, HPD's noise attenuation, susceptible groups, and noise's temporal structure., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Objective: This survey aimed to investigate exposure to welding fume in Australian workplaces and the use of protective and control measures among workers., Methods: Data were collected via a cross-sectional online survey of workers and employers involved in welding in Australia. Survey questions focused on the determinants of exposure to welding fume, welding experience and qualifications, and use of control measures., Results: There were 634 respondents to the survey across Australia of whom 577 (91%) were assessed as being exposed to welding fume, most at high levels. Welders undertook a wide range of types of welding, and higher-risk welding such as in confined and restricted spaces was common. Most workplaces did not have any form of mechanical ventilation, and use of air-supplied respiratory protection was poor even when ventilation was not used., Conclusion: Welders in Australia are exposed to several carcinogens, particularly welding fume, hexavalent chromium (CrVI) and nickel, and the use of control measures is sub-optimal., Implications for Public Health: Higher-order controls are the best way to reduce exposure to carcinogens in the workplace. The lack of use of these controls by Australian welders is concerning and needs to be a focus of attention by regulators and companies., Competing Interests: Conflicts of interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Tim Driscoll reports financial support was provided by Centre for Work Health and Safety. Lin Fritschi reports a relationship with OccIDEAS Pty Ltd that includes: equity or stocks., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

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Silicosis and other respirable crystalline silica-associated diseases, most notably tuberculosis, have long been substantial causes of morbidity and mortality in South Africa. For the mining and non-mining industries, silicosis elimination programmes have been developed with milestones regarding reduction of levels of exposure to respirable crystalline silica (RCS) and targets regarding the date of eradication. The present paper explores the feasibility of achieving these targets by investigating the evidence that levels of exposure and silicosis incidence rates have declined by an appraisal of the methods for data collection and reporting. In the mining industry the silicosis elimination programme is supported by the development and advocacy of leading practices to reduce the exposure. RCS exposure data are routinely collected according to a Code of Practice (CoP) and the results are reported to the Mine Health and Safety Inspectorate. As the CoP and the actual workplace practices have been demonstrated to have some flaws, there is some concern about the accuracy of the actual exposure data and the data interpretation. The annually reported levels of exposure suggest a decline, however, the actual levels of RCS as well as the number of exposed workers, were not reported over the last few years. With regard to the silicosis incidence rates, a steady decline of new cases is reported. However, there is a risk of under-diagnosis and- reporting especially in former miners. In the non-mining industries, a systematic baseline of RCS exposure levels and silicosis incidence is lacking. The reporting by industries on assigning of the workforce to exposure categories seems to be fragmented and incomplete. Consequently, any evidence of progress toward achieving the silicosis elimination target cannot be documented. Both the silicosis elimination target and the exposure milestone are aspirational but are unlikely to be achieved. Nevertheless, the formal mining industry may get close. Exposure control interventions, especially in the non-mining industries, should be developed and implemented and pragmatic methods need to be put in place to identify sources of new silicosis cases for targeted intervention.

Background Context: Exposure to surgical smoke remains a potential occupational health concern to spine operating room personnel. Using a smoke evacuator (local exhaust ventilation) is currently regarded as a primary means of protection, yet few studies have evaluated its utility in actual surgeries.Objective: To examine the utility of two common types of local smoke evacuators, a para incisional evacuator and a smoke evacuation pencil, in reducing surgical smoke exposure in spine surgery.Study Design: A prospective self-controlled study.Patient Sample: After the pre-estimation of sample size, 51 consecutive spine surgeries (25 and 26 patients using the para incisional smoke evacuator and the smoke evacuation pencil, respectively) were enrolled between February 2018 and March 2019.Outcome Measures: Two outcome measures were used to evaluate the level of surgical smoke exposure, which was defined as the concentration of ultrafine smoke particles in the air (number of particles per cm3, ppc) around the operating table: (a) the average smoke level was the arithmetic mean of all measurements recorded during the surgery; and (b) the peak smoke level was the highest measurement recorded.Methods: Consecutive surgeries that involved bilateral symmetrical surgical exposure of the spine via a posterior midline incision were evaluated. Cauterized smoke was evacuated by two smoke evacuators: a "para incisional evacuator," which used a flat broad suction pad positioned immediately adjacent to the incision (25 patients), and a "surgical smoke evacuation pencil" which is an incorporated part of the electrocautery (26 patients). The level of smoke exposure was measured separately when surgically exposing the two sides of the spine: starting with one side (determined randomly) with the smoke evacuator being turned on and, then, the other side with the smoke evacuator off. The results were compared between the two sides.Results: The para incisional smoke evacuator significantly reduced the average smoke level by an average of 59.7% (287 [interquartile range {IQR}: 126, 526] vs. 1,177 [IQR: 395, 2,702], p<.001). The surgical smoke evacuation pencil also reduced the average smoke level by an average of 44.1% (917 [IQR: 448, 1936] vs. 1,605 [IQR: 775, 4,280], p<.001). Both evacuators significantly reduced peak smoke levels as well.Conclusions: This study provides evidence supporting the utility of local smoke evacuation in reducing surgical smoke exposure in spine surgery. Such technology may help to improve the occupational health protection for spine operating room workers. [ABSTRACT FROM AUTHOR]

Mobile and handheld mapping systems are becoming widely used nowadays as fast and cost-effective data acquisition systems for 3D reconstruction purposes. While most of the research and commercial systems are based on active sensors, solutions employing only cameras and photogrammetry are attracting more and more interest due to their significantly minor costs, size and power consumption. In this work we propose an ARM-based, low-cost and lightweight stereo vision mobile mapping system based on a Visual Simultaneous Localization And Mapping (V-SLAM) algorithm. The prototype system, named GuPho (Guided Photogrammetric System), also integrates an in-house guidance system which enables optimized image acquisitions, robust management of the cameras and feedback on positioning and acquisition speed. The presented results show the effectiveness of the developed prototype in mapping large scenarios, enabling motion blur prevention, robust camera exposure control and achieving accurate 3D results.

We introduce a novel method to automatically adjust camera exposure for image processing and computer vision applications on mobile robot platforms. Because most image processing algorithms rely heavily on low-level image features that are based mainly on local gradient information, we consider that gradient quantity can determine the proper exposure level, allowing a camera to capture the important image features in a manner robust to illumination conditions. We then extend this concept to a multi-camera system and present a new control algorithm to achieve both brightness consistency between adjacent cameras and a proper exposure level for each camera. We implement our prototype system with off-the-shelf machine-vision cameras and demonstrate the effectiveness of the proposed algorithms on practical applications, including pedestrian detection, visual odometry, surround-view imaging, panoramic imaging, and stereo matching. [ABSTRACT FROM AUTHOR]

Drilling large holes (e.g., 10–20 mm diameter) into concrete for structural upgrades to buildings, highways, bridges, and airport runways can produce concentrations of respirable silica dust well above the ACGIH® Threshold Limit Value (TLV® = 0.025 mg/m3). The aim of this study was to evaluate a new method of local exhaust ventilation, hollow bit dust extraction, and compare it to a standard shroud local exhaust ventilation and to no local exhaust ventilation. A test bench system was used to drill 19 mm diameter x 100 mm depth holes every minute for one hour under three test conditions: no local exhaust ventilation, shroud local exhaust ventilation, and hollow bit local exhaust ventilation. There were two trials for each condition. Respirable dust sampling equipment was placed on a "sampling" mannequin fixed behind the drill and analysis followed ISO and NIOSH methods. Without local exhaust ventilation, mean respirable dust concentration was 3.32 (± 0.65) mg/m3 with a quartz concentration of 16.8% by weight and respirable quartz dust concentration was 0.55 (± 0.05) mg/m3; 22 times the ACGIH TLV. For both LEV conditions, respirable dust concentrations were below the limits of detection. Applying the 16.8% quartz value, respirable quartz concentrations for both local exhaust ventilation conditions were below 0.007 mg/m3. There was no difference in respirable quartz dust concentrations between the hollow bit and the shroud local exhaust ventilation systems; both were below the limits of detection and well below the ACGIH TLV. Contractors should consider using either local exhaust ventilation method for controlling respirable silica dust while drilling into concrete. [ABSTRACT FROM AUTHOR]

International guidelines recommend the use of ventilation systems in operating rooms to reduce the concentration of potentially hazardous substances such as anesthetic gases. The exhaust air grilles of these systems are typically located in the lower corners of the operating room and pick up two-thirds of the air volume, whereas the final third is taken from near the ceiling, which guarantees an optimal perfusion of the operating room with a sterile filtered air supply. However, this setup is also employed because anesthetic gases have a higher molecular weight than the components of air and should pool on the floor if movement is kept to a minimum and if a ventilation system with a unidirectional displacement flow is employed. However, this anticipated pooling of volatile anesthetics at the floor level has never been proven. Thus, we herein investigated the flow behaviors of isoflurane, sevoflurane, and carbon dioxide (for comparison) in a measuring chamber sized 2.46 × 1.85 × 5.40 m with a velocity of 0.3 m/sec and a degree of turbulence <20%. Gas concentrations were measured at 1,728 measuring positions throughout the measuring chamber, and the flow behaviors of isoflurane and sevoflurane were found to be similar, with an overlap of 90%. The largest spread of both gases was 55 cm at 5.4 m from the emission source. Interestingly, neither isoflurane nor sevoflurane was detected at floor level, but a continuous cone-like spreading was observed due to gravity. In contrast, carbon dioxide accumulated at floor level in the form of a gas cloud. Thus, floor level exhaust ventilation systems are likely unsuitable for the collection and removal of anesthetic gases from operating rooms. [ABSTRACT FROM AUTHOR]

We develop a methodology for index tracking and risk exposure control using financial derivatives. Under a continuous-time diffusion framework for price evolution, we present a pathwise approach to construct dynamic portfolios of derivatives in order to gain exposure to an index and/or market factors that may be not directly tradable. Among our results, we establish a general tracking condition that relates the portfolio drift to the desired exposure coefficients under any given model. We also derive a slippage process that reveals how the portfolio return deviates from the targeted return. In our multi-factor setting, the portfolio’s realized slippage depends not only on the realized variance of the index but also the realized covariance among the index and factors. We implement our trading strategies under a number of models, and compare the tracking strategies and performances when using different derivatives, such as futures and options. [ABSTRACT FROM AUTHOR]

Heat recovery ventilation (HRV) system is emerging as a sustainable technology to reduce human exposure to air pollutants in residential buildings. However, there is a lack of information on the HRV system performance for controlling both indoor-generated and outdoor-generated particles in a residential building. To fill this knowledge gap, we conducted field monitoring of indoor airborne particles with two representative HRV system operating modes (ventilation and circulation modes) in a full-scale residential testbed. The results reveal that the filter efficiency, airflow rate, and filter bypass factor of the HRV system play important roles in indoor particle concentrations. The indoor/outdoor concentration ratio is reduced by 72%–92% when operating the HRV system. For both circulation and ventilation modes, the bypass factor is crucial for the particle removal performance of the HRV system. A 20% filter bypass factor leads to up to a 50% increase in indoor exposure to outdoor-originated and indoor-generated PM 2.5 compared to the no-bypass scenario. Although circulation mode performed better than ventilation mode, both operating modes with a minimal bypass factor can effectively remove particles generated from indoor emission sources (e.g., incense stick burning and bacon pan frying). The study results suggest that HRV system can reduce human exposure to indoor-generated particles by 56%–90% and particle control performance hinges upon minimizing HRV filter bypass. • We investigate indoor particle removal due to a heat recovery ventilation system. • The HRV system can reduce human exposure to indoor-generated particles by 50–90%. • The filter bypass factor is crucial for the HRV particle control performance. • A 20% filter bypass factor can lead up to 50% increase in indoor PM2.5 exposure. [ABSTRACT FROM AUTHOR]

The duty to manage asbestos in non-domestic premises is described in the Control of Asbestos Regulations 2012. Health and Safety Executive (HSE) policy and guidance on asbestos in the built environment in Great Britain is that asbestos-containing materials (ACMs) that are in good condition and unlikely to be disturbed can be managed in place. Where ACMs are in poor condition or likely to be disturbed they should be repaired, encapsulated or, if necessary, removed. HSE and Government Office for Science hosted a stakeholder workshop to consider evidence on the management of ACMs in public buildings. Invitees attended from a range of backgrounds (including regulatory, government, academic, medical, public interest groups, and professional service providers). Participants considered the evidence, suggested nine evidence gap areas and ranked these according to preference in an anonymous vote. The top three suggested evidence gaps were: (i) the comparative risks of managing ACMs in place versus removal; (ii) improved measurement techniques at lower fibre concentrations; and (iii) building the evidence base on the effectiveness of asbestos management and safe removal. HSE will use the workshop outputs to inform its research planning. It is anticipated that a number of initiatives for shared research will be explored. [ABSTRACT FROM AUTHOR]

Task-based respirable crystalline silica (RCS) exposure monitoring data was collected from construction work sites across 3 Canadian provinces: Alberta, British Columbia (BC), and Manitoba. In total 373 RCS samples were obtained from 70 worksites across 44 companies. Sampling was conducted between May 2015 and August 2020. The overall geometric mean (GM) RCS exposure was 0.045 mg/m3 (geometric standard deviation, GSD = 6.8). Alberta had the highest average exposure and the highest variability with GM of 0.060 mg/m3 (GSD = 9.3), the GM in BC was 0.044 (GSD = 4.3), and in Manitoba the GM was 0.033 (GSD = 7.0). A multivariable model was built using forward stepwise linear regression modeling. Province, task type, work environment (indoor vs. outdoor), construction material, sampling duration, and engineering control use were all statistically significant predictors of exposure level in partial F-tests (P < 0.05). Overall, the model explained 42% of the RCS concentration variability. Task type contributed most to the model's explanatory power. The task type with highest average exposure levels was demolition (GM 0.30 mg/m3, GSD 0.49). Breaking (GM 0.16 mg/m3, GSD 8.4) and grinding (GM 0.081 m/m3, GSD 7.4) also had high-exposure levels. Working outdoors was associated with exposure levels 39% lower than indoors. Exposure control measures such as local exhaust ventilation and wetting were also associated with lower exposure levels. Among construction materials, Cement, sand, and stone were associated with higher RCS exposure levels relative to the reference material, concrete. The results of this study indicate that workers in western Canada remain exposed to RCS at levels that exceed the health-based American Congress for Governmental Industrial Hygienists Threshold Limit Value of 0.025 mg/m3. Although there were some differences in exposure levels between the provinces, the determinants of exposure were similar in all 3. The overall GM RCS exposure was 0.045 mg/m3 (geometric standard deviation, GSD = 6.8). Alberta had the highest average exposure and the highest variability with GM of 0.060 mg/m3 (GSD = 9.3), the GM in BC was 0.044 (GSD = 4.3), and in Manitoba the GM was 0.033 (GSD = 7.0)., (© The Author(s) 2023. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.)

Item bank stratification has been shown to be an effective method for combating item overexposure in both uni- and multidimensional computer adaptive testing. However, item bank stratification cannot guarantee that items will not be overexposed-that is, exposed at a rate exceeding some prespecified threshold. In this article, we propose enhancing stratification for multidimensional computer adaptive tests by combining it with the item eligibility method, a technique for controlling the maximum exposure rate in computerized tests. The performance of the method was examined via a simulation study and compared to existing methods of item selection and exposure control. Also, for the first time, maximum likelihood (MLE) and expected a posteriori (EAP) estimation of examinee ability were compared side by side in a multidimensional computer adaptive test. The simulation suggested that the proposed method is effective in suppressing the maximum item exposure rate with very little loss of measurement accuracy and precision. As compared to MLE, EAP generates smaller mean squared errors of the ability estimates in all simulation conditions. [ABSTRACT FROM AUTHOR]

Aquatic toxicity testing of nanoparticles (NPs) is challenged by their dynamic behavior in test suspensions. The resulting difficulties in controlling and characterizing exposure concentrations are detrimental to the generation of concentration-response data needed for hazard identification of NPs. This study explores the applicability of short-term (1, 2 and 3 h) pulse exposures as means to keep the exposure stable and at the same time disclose acute and chronic effects of AgNPs and CuONPs in D. magna . Dissolution, agglomeration and sedimentation were found to have less influence on exposure concentrations during 1–3 h pulses than for 24–48 h continuous exposures. For AgNPs, preparation of test suspensions in medium 24 h before toxicity testing (aging) increased stability during the short-term pulses. In pulse tests, organisms were exposed to the test materials, AgNPs and CuONPs for 1, 2 and 3 h, and afterwards transferred to clean medium and observed for 48 h (post-exposure period) for acute effects and for 21 d for chronic effects. AgNO 3 and CuCl 2 were used as reference materials for dissolved silver and copper, respectively. For all test materials, a 3 h pulse caused comparable immobility in D. magna (observed after 48 h post-exposure) as 24 h continuous exposure, as evidenced by overlapping 95% confidence intervals of EC 50 -values. In the 21 d post-exposure period, no trends in mortality or body length were identified. AgNP and AgNO 3 pulses had no effect on the number of moltings, days to first live offspring or cumulated number of offspring, but the number of offspring increased for AgNPs (3 h pulse only). In contrast, CuONP and CuCl 2 pulses decreased the number of moltings and offspring, and for CuONPs the time to first live offspring was prolonged. After CuONP exposures, the offspring production decreased more with increasing concentrations than for CuCl 2 exposures when taking the measured dissolved copper into account. This indicates a nanoparticle-specific effect for CuONPs, possibly related to the CuONPs accumulated in the gut of D. magna during the pulse exposure. Pulse exposure is an environmentally relevant exposure scenario for NPs, which for AgNPs and CuONPs enables more stable exposures and cause acute immobility of D. magna comparable to continuous 24 h exposures. Pulse exposure is likely relevant and applicable for other toxic and dissolving metal NPs, but this requires further research. [ABSTRACT FROM AUTHOR]

The current study compares the progressive-restricted standard error (PR-SE) exposure control method with the Sympson-Hetter, randomesque, and no exposure control (maximum information) procedures using the generalized partial credit model with fixed- and variable-length CATs and two item pools. The PR-SE method administered the entire item pool for all conditions; whereas the Sympson-Hetter and randomesque procedures did not administer 27%-28% and 14%, respectively, of item pool 1 and about 45%-50% and 27%-29% of item pool 2, respectively, of the items that were not administered. PR-SE also resulted in the smallest amount of mean item overlap averaged across replications. These results were obtained with similar measurement precision compared to the other methods while improving on the utilization of the item pools, except for very low theta levels (less than -2) for item pool 2, where a mismatch with the trait distribution occurs. [ABSTRACT FROM AUTHOR]