Subjective Comfort Assessment Research Articles

A bench-top evaluation of the Ily® robotics assisted tele console system in ureteroscopy by medical students, residents and urologists: does prior videogaming experience help shape the learning curve?

Previous studies have demonstrated an association between video-gaming experience (VGE) and improved robotics skills. We aimed to evaluate the initial learning curve for the Ily® robotics system (Sterlab, Sophia Antipolis, France) when applied to flexible ureteroscopy (FU) among both medical students and urology surgeons. There were two groups, surgeons and students. An initial questionnaire was completed detailing basic demographics and experience. In part one, both groups performed two simple timed tasks using an Ily® mounted single-use RAU. In part two, group 1 repeated both tasks using a hand-held FU. A subjective assessment of comfort, intuitiveness and a NASA Task Load Index were then completed. There was a total of 28 participants. Among medical students with VGE (n = 9, 64%)., average calyceal inspection time was 185 ± 80s; 133 ± 42s; 121 ± 71s. For non-gamers (n = 5, 36%), average times were longer at 221 ± 97s; 134 ± 35s; 143 ± 68s respectively. Average calyceal inspection time for videogaming surgeons (n = 8, 57%) was 126 ± 95s; 98 ± 40s; 107 ± 71s, respectively. For non-gamers average inspection times were longer at 150 ± 73s; 114 ± 82s; 111 ± 47s, respectively. None of these differences achieved statistical significance. Surgeons trial speeds were, however, significantly faster by hand-held compared to RAU: by 103, 81 and 82s respectively (p < 0.05). These results show that ex- or current- video gamers do not have a significant advantage in time to perform FU. Any early advantage conferred to ex- or current- gamers may be rapidly overcome.

Effects of preoperative and postoperative carbohydrate loading on gastrointestinal function and stress-induced inflammation after radical prostatectomy

Background: Early postoperative oral clear liquid diet has been shown to enhance postoperative recovery. However, the standard strategy for this diet has not been established. The authors’ aim was to investigate the combined effect of preoperative and early postoperative carbohydrate loading on postoperative stress and gastrointestinal function of patients by standardizing the starting time, type, volume, and concentration of carbohydrate drinks. Materials and methods: Fifty-three patients undergoing radical prostatectomy were randomly assigned to two groups. Both groups received a carbohydrate loading of 400 ml (12.5%) overnight and 2 h before surgery. The intervention group (n=29) started a 400 ml (12.5%) carbohydrate loading 6 h after surgery and consumed it within 24 h, while the control group (n=32) drank water. The primary outcomes–postoperative fasting blood glucose, fasting insulin, C-reactive protein (CRP), interleukin-6 levels, and gastrointestinal function–were recorded. Secondary outcomes included subjective comfort assessment, the first postoperative intake of semi-fluid food time, and drainage volume. Results: Compared with the control group, the intervention group had lower CRP levels on postoperative day 1 (POD1)/POD2 and less drainage volume on POD1. The intervention group also experienced shorter times to the first postoperative flatus and the first consumption of semi-fluid foods; their 72-h postoperative protein intake was higher than that of the control group. Conclusion: The results suggest that combined preoperative and postoperative carbohydrate loading can alleviate stress-induced inflammation and promote the recovery of postoperative gastrointestinal function.

Remote Orthotic Fabrication Method Using Small Three-Dimensional Printers and Computed Tomography Data:A Technical Report.

Computer-aided design and manufacturing (CAD/CAM) methods have gained prominence in early orthotic provision. This study introduces an innovative approach using compact three-dimensional (3D) printers and computed tomography data to generate segmented body models for traditional Damen corset orthoses. The goals included evaluating the comfort and fit of orthoses and assessing the effectiveness of our approach for prosthetic companies with limited financial resources. Lumbar and thoracolumbar orthoses were crafted via CAD/CAM. Four healthy patients wore the orthoses, with whom immediate and 1-week comfort and fit assessments were conducted. A prosthetist assessed fit, and the Japanese edition of OPUS-CSD, the Orthotics Prosthetics Users' Survey-Client Satisfaction with Device, was used for subjective assessment of comfort and fit. The fit evaluations were satisfactory for all patients with positive predefined criteria. Questionnaire responses confirmed high satisfaction and comfort, confirming a successful orthosis fit. We established an orthotic fabrication method using CAD/CAM methods with 3D printers. Additionally, we confirmed the comfort and fit of the corsets so produced. The initial cost of 3D printers is lower than that of traditional carving machines, enabling even small-scale orthotic fabrication facilities to utilize CAD/CAM methods. Further research and refinements of this manufacturing approach are expected to expand its applicability.

Designing a User-Centered Inspection Device’s Handle for the Aircraft Manufacturing Industry

In aircraft manufacturing settings, workers are frequently exposed to biomechanical risk factors, mainly in the later stages of the production processes, including inspection tasks. To support the development of a novel inspection device appropriate for the end-users and their tasks, this study presents a user-centered approach for the device’s handle. Three different handles were proposed, and the current study aims to find out which handle can offer (1) the best ergonomic conditions and (2) the best stability in holding the device in hand during an inspection task. To this end, 23 volunteers participated in the experimental assessment, which comprised qualitative and quantitative data. A questionnaire was used for subjective comfort assessment. Partial times to execute the task studied, stability metrics of the device during its handling, and kinematic and electromyographic data of the upper limb recruited were measured and analyzed to compare the three handles. Outstanding results include the higher comfort perceived by the participants working with the selected handle for the final design, as well as the reduction in muscle effort. Globally, the results obtained demonstrated that the handle user-centered design potentiates good efficiency and usability of the novel device.

The effect of whole-body vibration on public transportation passenger performance while typing on smartphones

This study verified typing performance on smartphones of public transportation passengers using subjective assessments of comfort and difficulty and objective assessments of the number of errors and typing speed. Three frequency values (5, 10, and 15 Hz), two magnitudes (0.6 and 1.2 m/s2) and two types of operating systems (Android and IOS) were adopted. Tests without vibration were applied to analyse the residual effect of vibration. The results showed that vibration significantly influences comfort. The higher the frequency, the less errors and the faster the typing speed. In the magnitude analysis, the increase caused a greater number of errors and greater difficulty. In both assessments, the discomfort was proportional to the increase in frequency or magnitude and the number of errors was inversely proportional to the typing speed. Finally, the IOS operating system showed worse comfort when compared to Android, although no significant differences were observed for the objective assessment. Practitioner summary: Public transportation passengers are exposed to WBV while typing on smartphones. The results showed that vibration influences comfort, the number of errors and the typing speed. Therefore, manufacturers should be aware of the level of vibration that vehicles are exposed to in order to provide more performance to the user. Abbreviations: WBV: whole-body vibration; PID: proportional–integral–derivative; RMS: root mean square; HLM: hierarchical linear modeling; OLS: ordinary least squares; STH: seat-to-head

Effects of overnight storage conditions on conventional complete removable prostheses.

To evaluate the effects of overnight storage conditions on the dimensional stability and retention of prostheses, as well as the participant's subjective perception of these interventions. Subjects with maxillary complete prostheses (CRPs) were randomly assigned to receive two interventions in a crossover design: storing the CRPs overnight in a dry or wet environment with a cleansing tablet. The denture intaglio surface was scanned, and outcome measures were collected before each intervention (BLN), post ntervention (PIS), and after immersion in water for 15 minutes after the intervention (WOC). Dimensional changes were analyzed for the total surface, anterior flange, palate, and tuberosities. Retention force was measured using a dynamometer, and the participants' subjective assessment of comfort, fit, and retention of their CRPs were collected. After verifying normal distribution, paired t and Wilcoxon signed-rank tests were used to check for any statistical significance (α = .05). Ten participants (mean age: 76.5 ± 5.9 y) were recruited in this study. Between BLN and PIS, the dimensional changes after dry intervention were significantly less than when stored wet for total surface (P = .009), anterior flange (P = .028), and the palate (P = .005). No difference was found between the effects of storage or washout interventions on objectively measured CRP retention. However, after WOC following dry storage, participants perceived a lower retention (P = .021), and a more comfortable palate after WOC following the wet intervention (P = .018). For dimensional stability, dry overnight storage of removable prostheses can safely be recommended when indicated. Immersion in water for 15 minutes does not seem to add advantages.

Testing the relationship between objective indoor environment quality and subjective experiences of comfort

ABSTRACT At present, workplace researchers lack a suitable methodology for combining objective indoor environmental quality (IEQ) data with repeated subjective assessments of comfort in real offices. To address this gap, we conducted a study at two office sites. Four IEQ parameters (carbon dioxide, temperature, humidity, and illuminance) were continuously monitored at each site, and brief environmental comfort surveys were sent to employees’ smartphones four times per day across the study period. In total, 45 employees across the two sites completed 536 surveys. The findings confirm that the repeated sampling approach is a more appropriate method for measuring comfort than a questionnaire delivered at one time only. Adherence to recommended temperatures reduced the risk of thermal discomfort, however this effect was weak and other predicted associations between the physical environment and environmental comfort were not supported. The results also showed a strong association between environmental comfort and self-rated productivity, such that employees rated themselves as most productive when they were satisfied with noise levels, temperature, air quality, and lighting within the office. Overall, the results highlight that it is critically important to consider strategies for optimising occupant comfort, although this is unlikely to be achieved through adherence to environmental comfort boundaries alone.

Simulation of three intraoral radiographic techniques in pediatric dental patients: subjective comfort assessment using the VAS and Wong-Baker FACES Pain Raiting Scale

BackgroundPerception of pain associated with intraoral radiography in pediatric patients was evaluated through statistical comparisons of data obtained using the Wong-Baker FACES Pain Raiting Scale (WBFPRS) and visual analog scale (VAS) scoring.MethodsA total of 75 pediatric patients aged 6–12 years were included in this study. Simulations of each of three radiological methods (analog films, CCD sensor and phosphorus plates) were performed on 25 pediatric patients. Following the simulations, the meaning of each facial expression on the WBFPRS and the numbers on the VAS were explained to each child. For the comparison between groups, the homogeneity of the variances was tested with Levene’s test; because the variances were not homogeneous, Welch’s test was used. Tamhane’s T2 test was used because the homogeneity assumption was not provided to determine the source of the difference between the groups.ResultsWhen the conventional method was compared to the PSPL (photostimulable phosphor luminescence) method, no significant differences were noted in either the WBFPRS or VAS results (p >0.05). The results obtained from both of the scales were significantly different between the conventional method and the CCD sensor method (p < 0.05). When the PSPL and CCD sensors were compared, a significant difference was observed for the WBFPRS (p < 0.05). It was found the highest level of pain scores when used the CCD sensor method than the analog film and PSPL methods (p < 0.05).ConclusionsIt is expected that digital radiographic techniques will be improved in the future and that their disadvantages will be eliminated, resulting in imaging devices that are more comfortable for pediatric patients.

Subjective Comfort, Coping-Strategies, and Types of Accentuations of Personality of Russian and Indonesian University Students

This article introduces a comparative study of subjective comfort, coping-strategies, and types of accentuations of the personalities of Russian and Indonesian university students. The research employed the scale of subjective comfort assessment by A. Leonova, coping-test by R. Lazarus, and a test-questionnaire by G. Schmieschek and K. Leonhard. The experiment included 30 Russian and 30 Indonesian students (mean age – 20,5). The research revealed general qualities and differences between indicators of types of personality accentuations and ways of mastering stress. The students appeared to have no significant distinctions on the level of subjective comfort, which was normal. The Indonesian students distanced themselves and used self-control while facing stress more than Russian students. The most expressed types of personality accentuation of the Russian students were emotivity, demonstrativeness, and exaltation. As for the Indonesian students, it was pedantry. The subjective comfort of the Russian students had four interrelations with types of personality aссentuation, i.e. direct interrelations with emotive personality aссentuation and demonstrative and negative interrelations with obsessive and dysthymic personality aссentuations. There were three connections with coping-strategies, i.e. direct interrelations with "planning" and "positive reevaluation" strategies and an inverse one – with "fleeing" strategy. The subjective comfort of the Indonesian students had four interrelations with types of personality aссentuations: direct interrelations with hyperthymic and demonstrative aссentuations and an inverse one – with excitable and emotive. They had two interrelations with coping-strategies: inverse interrelations with "distancing" and "fleeing" strategies. The results proved the interdependence of subjective comfort and personal traits and the formed ways of mastering stress. The data obtained can be used in programs for coping-resource development in students.

THE USE OF ENTERAL NUTRITION IN BOWEL CLEANSING BEFORE COLONOSCOPY

AIM: to evaluate the effectiveness of bowel cleansing before colonoscopy using enteral nutrition agent «Nutridrink» as the single nutrient. MATERIALS AND METHODS: a prospective comparative study included 150 patients (83 females, aged 20-65 years), who underwent diagnostic colonoscopy. To assess the quality of bowel cleansing the Likert scale was used. Subjective assessment of patients' comfort was performed by patients on a 10-point visual scale (from 0 - «excellent» to 10 - «extremely negative»). RESULTS: the quality of colon cleansing before colonoscopy was significantly better in patients who got enteral nutrition, especially in comparison with patients with standard protein diet. Subjective assessment of comfort during cleansing was better in the group of patients who used Nutridrink as the only source of nutrition as well. CONCLUSION: use of enteral nutrition as a part of bowel cleansing before colonoscopy can replace the protein diet.

On-site monitoring and subjective comfort assessment of a sun shadings and electric lighting controller based on novel High Dynamic Range vision sensors

Electric lighting is responsible of about one fifth of the electricity demand of buildings in Switzerland. Therein, integrated control of sun shadings and artificial lighting can mitigate the electricity demand while maintaining the user comfort and performance. However, the drawback of the existing smart building technologies is that they do not take visual comfort effectively into account, one of the essential aspects of indoor human comfort. An ‘on-the-fly’ measurement of a visual comfort index, Daylight Glare Probability (DGP), by a novel High Dynamic Range (HDR) vision sensor was introduced into the building control system optimizing the sun shadings position and electric lighting status. Two identical office rooms (reference and advance) of the LESO solar experimental building were occupied by 30 human subjects during 15 afternoons and were used to experimentally compare the performance and users acceptance of the fuzzy logic based control system against a best practice reference system. A paper-based and a computer-based visual tests, subjective self-reported visual comfort surveys and precise monitoring of the electric lighting consumptions were carried out.The results indicates that the electricity demand of the advanced system is 32% lower than the reference one. It also shows that, while the subjects’ visual performance remain comparable in the two office rooms, the advanced control system is successful in preventing discomfort glare sensations.

FORECASTING OF SUBJECTIVE COMFORT IN TRAM USING ORDINAL LOGISTIC REGRESSION AND MANIFOLD LEARNING

Comfort in a vehicle has a very important role to play as one of the most important dynamic performance characteristics of rail vehicles. It is the factor of ever-increasing importance, even creating a specialized branch of engineering associated with relation between human limitations and designing of machines: human–factors engineering. The vibration is known to be a major factor that affects and deteriorates ride comfort. For evaluating ride comfort in rail vehicles, there have been developed methods resulting in the creation of many standards and multiple criteria used and even standardized in different countries. One of the authors, J. Szczygie · designed and performed a passive experiment to collect data describing physical conditions of ride and associated subjective assessments of comfort. Panel of fourteen people during the tram ride made synchronous subjective assessments of comfort, assessing it on a discrete ordinal scale of 0 to 5, using electronic panels connected to the computer. At the same time computer through sensors recorded values of acceleration in three perpendicular axes. It made possible to correlate the fuzzy subjective evaluations with objective physical measurements. Because of the discrete type of fuzzy ratings of comfort, natural way of modelling is the ordinal logistic regression. The classic form of the ordinal logistic regression assumes that in the space of explanatory factors there are parallel activation hyper-planes slightly disturbed by unknown or uncontrolled noise factors. In fact, the assumption of linearity is a very strong idealization and leads to considerable misclassifications. The original space of explanatory factors is 11-dimensional with ten continuous dimensions and one discrete. Then the multivariate method, principal component analysis (PCA), was used to identify principal components, which are responsible most to the variability of the studied set. The scree plot was used to identify the number of significant PCA factors. The use of PCA revealed that the area occupied by the data set is approximately 6-dimensional. However, the dimensionality reduction of explanatory variables set did not lead to better forecasting accuracy. A more subtle analysis involving discretization techniques showed that activation hyperplanes are highly curved in the six-dimensional area identified by PCA but their dimensionality is much lower. The details of the procedure are described in the article. The article conclusion is that is necessary to introduce curvilinear coordinate system embedded into the shapes of activation hyper-planes to obtain better classification.

Comparative Study of Misoprostol in First and Second Trimester Abortions by Oral, Sublingual, and Vaginal Routes.

To identify an effective misoprostol-only regimen for termination of pregnancy between 12 and 20weeks of gestation, a prospective randomized study comparing sublingual, vaginal, and oral routes of administration of misoprostol was done. One hundred and fifty women (12-20weeks gestation) were randomly divided into three groups and given 400mcg misoprostol sublingually, vaginally, and orally every 4h up to a maximum of four doses. Primary outcome was the success rate at 24h. Secondary outcomes were failure rate, induction-abortion interval, and need for surgical intervention. Various side effects and patients' subjective assessment of comfort with the route of administration were also studied. Success rate at 24 h of sublingual (86%) group was higher compared to oral (64%) group (P=0.011). Complete abortion rate of sublingual (76%) group was higher than that of oral (48%) group (P=0.004). There was no significant difference in the failure rate and need for surgical intervention in the three groups. Induction-abortion interval in sublingual (9.8±3.6h) and vaginal (10.6±2.9h) groups was shorter than that in oral group (14.3±3.3). Diarrhea occurred significantly more in the oral group (28%) and sublingual (22%) compared to vaginal group (6%). Fever was significantly higher in vaginal (36%) than that in the oral group (12%). Oral route of administration was most comfortable. Sublingual route results in significantly higher abortion rate compared to oral route. Vaginal route has efficacy similar to sublingual route.

In-eye performance of soft contact lenses made from different materials

The in-eye performance of soft contact lenses may be affected by the material from which they are fabricated and may alter during wear. This study describes clinical and laboratory experiments that were conducted in order to examine the in-eye performance of eight soft contact lenses manufactured from different materials; these materials (and nominal water contents) were: HEMA/VP 40%, HEMA/VP 55%, HEMA/VP 70%, VP/MMA 55%, VP/MMA 70%, HEMA 40%, HEMA/MAA 55% and HEMA/MAA 70% (HEMA: 2-hydroxy-ethyl methacrylate, VP: vinyl pyrrolidone, MMA: methyl methacrylate, MAA: methacrylic acid). Two lenses from each of the eight soft contact lens groups were used in experiments concerning their parameter stability. Six subjects were fitted with lenses for 1 day. Verification of back optic zone radius, total diameter, back vertex power, centre thickness and water content was undertaken at 20 °C. In vitro measurements of total diameter were taken at 35 °C before lens fitting and after 6 h of lens wear. In vivo measurements of lens centration, up-gaze lag, post-blink movement, total diameter and subjective assessment of comfort were taken (a) immediately after lens insertion (1 min), (b) 20 min later and (c) 6 h later (same day). The majority of differences of the in vivo parameters between lens types (with respect to lens centration, lag, movement on blink, lens total diameter and comfort) were not found to be statistically significant throughout the 6 h wearing period. It was also found that lenses increase in diameter when first placed on the eye and decrease in diameter when they were removed from the eye. The information generated in study concerning the in-eye performance of soft contact lens materials may assist the contact lens industry and contact lens practitioners in developing and prescribing soft lenses with optimal performance characteristics.

High water content versus low water content—Does monthly replacement affect the difference?: A comparison between the Focus ® and Medalist ™ lenses under identical conditions of use

The frequent replacement of contact lenses has developed primarily as a means of maintaining a high level of hygiene with soft lenses. To determine the differences in the performance of a low-water-content (Bausch & Lomb Medalist ™) and a high-water-content (CIBA Vision Focus ®) lens when used for monthly replacement, we carried out a 3-month, randomized, contralateral, single masked study using daily wear. There was no significant difference between the lenses in terms of ocular physiology, fitting performance, or spoilation. Handling of the high-water-content lens was judged to be better for insertion, removal, cleaning, and disinfection and determining whether the lens was inside out ( p < 0.05). Pooled subjective assessments of comfort, vision, and overall satisfaction gave a statistically significant patient preference ( p < 0.05) for the high-water-content lens. Unscheduled replacements of damaged lenses were low (<2%) and statistically insignificant between the lens types. These results imply that, with frequent replacement, the normally perceived disadvantages of handling, deposition, and fragility for high-water-content lenses, as opposed to low-water-content soft lenses, do not necessarily apply.

Corneal distortion caused by a hydrogel contact lens deposit

The frequent replacement of contact lenses has developed primarily as a means of maintaining a high level of hygiene with soft lenses. To determine the differences in the performance of a low-water-content (Bausch & Lomb Medalist™) and a high-water-content (CIBA Vision Focus®) lens when used for monthly replacement, we carried out a 3-month, randomized, contralateral, single masked study using daily wear. There was no significant difference between the lenses in terms of ocular physiology, fitting performance, or spoilation. Handling of the high-water-content lens was judged to be better for insertion, removal, cleaning, and disinfection and determining whether the lens was inside out (p < 0.05). Pooled subjective assessments of comfort, vision, and overall satisfaction gave a statistically significant patient preference (p < 0.05) for the high-water-content lens. Unscheduled replacements of damaged lenses were low (<2%) and statistically insignificant between the lens types. These results imply that, with frequent replacement, the normally perceived disadvantages of handling, deposition, and fragility for high-water-content lenses, as opposed to low-water-content soft lenses, do not necessarily apply.

Factors Influencing Short-Term Pain and Injuries in Tennis

Pain, discomfort, and/or injuries in tennis can be influenced by the individual movement pattern and the external and/or internal boundary conditions. The influence of external boundary conditions on the occurrence of short-term pain was studied in a prospective study with 229 subjects. The boundary conditions investigated were shoe, temperature, type and length of game and subjective assessment of comfort, sole grip, and lateral stability Pain was reported by 40% of the 171 subjects included in the final analysis. It was frequently reported in the first two playing sessions but less frequently afterward. Discomfort was the dominant type of pain, accounting for 71.6% of all reported cases. The foot was the major site of pain (85%). The boundary conditions influencing pain were found to be the shoe (the more flexible shoe 1 had less pain than the suffer shoe 2), the type of game (competitive more than recreational), and the length of the game (longer playing sessions with more pain). Subjective assessment of comfort, sole grip, and lateral support also showed differences for the pain/no pain groups. Subjects who complained about these aspects were more frequently in the pain groups. The results show that the occurrence of pain in tennis can be influenced by various external boundary conditions.

An Automated Methodology for Conducting Human Factors Evaluations of Protective Garments

A technique has been developed to quantify the restrictions to aircrew mobility produced while wearing various Chemical-Biological Warfare (CBW) protective garments. Twelve range-of-motion movements of three body areas were analyzed: (1) vertical and horizontal movements of head, arm and torso; (2) Horizontal forearm adduction from elbow; (3) Vertical movement of upper leg from hip and lower leg from knee. All subjects performed a three-minute video-displayed psychomotor tracking task while wearing six different test garments. They also completed questionnaires on subjective assessments of comfort, mobility, and general acceptability. Two of the ensembles allowed considerably more mobility than the other four. Performance scores on the tracking task and aircrew subjective ratings agreed with the mobility ratings.

U.K. deep diving trials.

Using a breathing medium of 40 kPa oxygen, remainder helium, 18 volunteer subjects participated in a series of 15 exposures to pressures equivalent to depths of 180-540 m s.w. The time of exposure at these pressures was mostly 2 days, except for the 540 m s.w. exposure, when 6 days were spent at full pressure. Compression procedures, based upon placing 'stages' at 60 m s.w. intervals, evolved with experience and proved to be a highly successful way of achieving acceptable pressure-time courses. Decompression combined slow linear release of pressure with overnight halts for sleep. On one occasion a depth of 660 m s.w. was reached by breathing 40 kPa oxygen, 10% nitrogen, remainder helium. Throughout all exposures, teams of investigators followed the changes in cardiovascular, respiratory, haematological, neurophysiological and metabolic status, and mental performance of the volunteers. Some major findings were that the neurophysiological and behavioural changes could be assigned to the motor, or vestibular, or cerebral, or autonomic systems, and were mainly first observed during compression. The subjects suffered, apparently from severe nitrogen narcosis, when breathing 10% (by volume) nitrogen in oxygen-helium at 420 m s.w. Lung ventilation was remarkably adaptable to the oxygen requirements of exercise at all depths, but cardiac output was adversely affected at 540 m s.w., particularly for heavier workloads. Ventilatory responses to carbon dioxide were significantly elevated after diving. Thermal balance was seen to be precarious, but nevertheless it was achieved by the normal subjective assessments of comfort. Water loss was affected by diminished evaporation from the skin. Skin temperature sensitivity was changed and took many days after the dives to return to normal. Energy requirements increased for work purposes, but basal metabolic rate was undisturbed. Body chemistry altered at pressures in excess of 300 m s.w., for example thyroid hormone and nitrogen balances were affected. No decompression sickness was encountered until the pressures were low, but marked haematological changes could occur during decompression. Every change that occurred during these dives reverted to normal, mostly before the end of the decompression. It is concluded that diving with oxygen-helium breathing mixtures to depths as great as 540 m s.w. can be effective and safe. An attempt is made to assess the physiological significance of the principal findings.

Thermal comfort in milking parlours

The frequent complaints of adverse conditions associated with milking often relate to thermal discomfort. Three farms providing 13 milkers were selected for a survey to establish details of the thermal environment most acceptable and practical to achieve in milking parlours. The results, which were analysed by the probit method, were obtained by monitoring the environmental variables and recording the milkers' subjective assessments of comfort whilst milking. There was no interference with either work routines or thermal conditions. The most reliable indicator of comfort was found to be ambient temperature and the control of this variable in the ranges 11°C to 15.5°C for the winter and 16.5°C to 19.5°C for the summer is recommended. The performance of the milkers was not found to be related to temperature.