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K C Parsons

Publications and source records attributed to K C Parsons.

At least 19 recordsLinked to original sources
PubMed2004

Organochlorines in black-crowned night heron (Nycticorax nycticorax) eggs reflect persistent contamination in northeastern US estuaries.

Colonially nesting aquatic birds can indicate site-specific contamination because they are high-level predators and dependent upon local resources during the breeding season. We compared persistent organochlorine concentrations in black-crowned night heron (Nvcticorax nvcticorax) eggs collected in 1992-93 among areas of known contamination (New York Harbor, Boston Harbor, Cape Cod, and Delaware Bay) and a reference site (Nantucket Island) in the northeastern United States (7-16 eggs/site). Total PCBs, p,p'-DDE, oxychlordane, heptachlor epoxide, and trans-nonachlor were detected in most eggs and were significantly higher in New York Harbor compared to all other sites (ANOVA on factor scores from the first principal component, which accounted for 75% of data variance, p < 0.0001). New York also had the highest contamination index (the number of Superfund sites within 20 km of the colony) among the sites. Nantucket, the reference site, had consistently low contamination in eggs, and the lowest contamination index. We conclude that black-crowned night heron eggs are useful indicators of site-specific persistent organochlorine contamination, as indexed by the number of nearby Superfund sites.

Animals↗
PubMed2000

Organochlorine and metal contaminant exposure and effects in hatching black-crowned night herons (Nycticorax nycticorax) in Delaware Bay.

Pea Patch Island in Delaware Bay is the site of the largest heronry north of Florida. From 1989-93, the population of nine species of wading birds numbered approximately 12,000 pairs, but has recently declined to about 7,000 pairs. Because Delaware Bay is a major shipping channel and receives anthropogenic releases of toxic substances from agricultural, industrial, and municipal point and nonpoint sources, contaminant exposure and effects to the heronry have been an ongoing concern. In 1997, pipping (early hatching stage) black-crowned night herons (Nycticorax nycticorax) were collected from separate nests at Pea Patch Island and from a coastal reference site, Middle Island in Rehoboth Bay, Delaware. There was no evidence of malformations or hepatic histopathological lesions in embryos, and their body and liver weights did not differ between sites. Biomarkers of petroleum hydrocarbons, polyhalogenated contaminant, and metal exposure (cytochrome P450 induction and oxidative stress responses) did not differ (p > 0.05) between sites, although activities of benzyloxy-O-dealkylase and ethoxyresorufin-O-dealkylase were somewhat elevated in 3 of the 15 embryos collected from Pea Patch Island. Concentrations of 21 organochlorine pesticides and metabolites were relatively low at both sites, with p,p'-DDE values well below the threshold associated with eggshell thinning. Although total PCB concentration was modestly elevated (p < 0.05) in Pea Patch Island heron embryos, levels of arylhydrocarbon receptor-active PCB congeners, polychlorinated dibenzodioxins and dibenzofurans, and toxic equivalents were low and did not differ between sites. Concentrations of Cd and Mn in pipping embryos from Pea Patch Island were slightly greater (p < 0.05) than values observed in Middle Island embryos, but levels of these and the other metals and metalloids (e.g., Hg and Se) were below values associated with toxicity. In conclusion, it seems unlikely that chlorinated hydrocarbon and metal contaminant exposure constitutes a direct threat to the reproductive success of black-crowned night herons at Pea Patch Island. However, low-level exposure to these contaminants may constitute one of many stressors that in combination could adversely affect the stability of the wading bird population at this large heronry.

Animals↗
PubMed2000

Environmental ergonomics: a review of principles, methods and models.

A review of the principles, methods and models used in environmental ergonomics is provided in terms of the effects of heat and cold, vibration, noise and light on the health, comfort and performance of people. Environmental ergonomics is an integral part of the discipline of ergonomics and should be viewed and practised from that perspective. Humans do not respond to the environment in a way monotonically related to direct measures of the physical environment. There are human characteristics which determine human sensitivities and responses. Practical methods for assessing responses to individual environmental components are presented as well as responses to 'total' environments and current and proposed International Standards concerned with the ergonomics of the physical environment.

Cold Temperature↗
PubMed2000

Intravenous infusion of 4-AP in chronic spinal cord injured subjects.

STUDY DESIGN: A prospective double blind cross over trial of intravenous 4-Aminopyridine (4-AP). OBJECTIVE: To determine the efficacy of this drug in the treatment of spinal cord injured (SCI) patients for neurologic impairment, pain and spasticity. SETTING: The post anesthesia care unit (PACU) of a tertiary care acute hospital. METHODS: Twelve paraplegic patients were enrolled in a double blind cross over intravenous trial of 4-Aminopyridine (4-AP). Thirty milligrams of 4-AP or placebo were administered over a 2 h period. Patients were serially examined during and after the infusion clinically for pain, sensorimotor function, hypertonicity and motor control using electromyography (EMG). Samples of blood and cerebrospinal fluid (CSF) were also analyzed at similar intervals. RESULTS: Despite penetration of 4-AP into the CSF, no significant differences were noted in the clinical and EMG parameters at the times measured. Individual changes in sensory function were reported by some patients in both the placebo and 4-AP trials, however mean values were not robust. Frequently, patients complained of unpleasant symptoms during the 4-AP infusion. CONCLUSION: The intravenous route may not be the best way to administer this drug as no short term benefits were observed.

4-Aminopyridine↗
PubMed1999

Appropriateness of international heat stress standards for use in tropical agricultural environments.

Where a danger to health from heat stress is identified, standards allow decisions for implementing measures to reduce the heat stress to be made. These standards, specifically ISO 7243 (Wet Bulb Globe Temperature Index, WBGT) and ISO 7933 (Sweat Required, SWreq) were designed with European and American subjects, primarily for use in those countries. While the scope of the standards is international, little consideration has been made about how valid and usable they are in industrially developing countries. This investigation evaluated ISO 7933 and ISO 7243 in terms of validity and usability. A tropical agricultural task was simulated; 16 subjects plucking tea leaves for 2 h, (ta = tr = 37.18 degrees C; va = 0.16 m/s; rh = 70.17%). While ISO 7243 was valid (if slightly over protective) and usable, ISO 7933 was over protective and underestimated sweat and evaporation rates in its predictions. The discrepancies between predicted and observed results were attributed primarily to the calculations related to clothing in the standard. Furthermore, ISO 7933 was unusable without a computer; in regions where access to such technology may be limited, a simpler method of presentation is required.

Adolescent↗
PubMed1999

An ergonomics investigation into human thermal comfort using an automobile seat heated with encapsulated carbonized fabric (ECF).

This report presents the results of an ergonomics investigation into human thermal comfort using an automobile seat heated with an encapsulated carbonized fabric (ECF). Subjective and objective thermal comfort data were recorded while participants sat for 90 min in a heated and a non-heated automobile seat in an environmental chamber. Eight male participants each completed eight experimental sessions in a balanced order repeated measures experimental design. The conditions in the chamber were representative of a range of cool vehicle thermal environments (5, 10, 15 and 20 degrees C; in the 20 degrees C trial participants sat beside a 5 degrees C 'cold wall'). Participants in the heated seat condition used the heating controller with separate temperature control over the back of the seat (squab) and bottom of the seat (cushion) in an effort to maintain their thermal comfort while wearing the provided clothing, which had an estimated insulation value of 0.9 Clo. The trials showed that participants' overall sensations remained higher than 'slightly cool' in the heated seat at all temperatures. Participants' overall discomfort remained lower (i.e. more comfortable) than 'slightly uncomfortable' at temperatures ranging down to nearly 5 degrees C in the heated seat. Hand and foot comfort, sensation and temperature were similar in both seats. Asymmetric torso and thigh skin temperatures were higher in the heated seat although no significant discomfort was found in the front and back of the torso and thigh in either seat. Participants reported no significant difference in alertness between the control and heated seat.

Adult↗
PubMed1999

International standards for the assessment of the risk of thermal strain on clothed workers in hot environments.

The International Standards Organisation (ISO) has produced an integrated series of international standards for the assessment of human responses to thermal environments. They include standards for the assessment of thermal comfort, heat stress and cold stress and many have been adopted as European and British standards. This paper describes the series of standards and in particular those concerned with the assessment of risk in hot environments. A three tier approach is taken which involves a simple thermal index that can be used for monitoring and control of hot environments (ISO 7243), a rational approach which involves an analysis of the heat exchange between a worker and his or her environment (ISO 7933) and a standard that describes the principles of physiological measurement which can be used in the establishment of personal monitoring systems of workers exposed to hot environments (ISO 9886). The standards are self-contained and can be used independently. In any comprehensive assessment however they would be used in conjunction. The simple index provides a first stage analysis and can confirm whether or not there is likely to be unacceptable thermal strain. Where a more detailed analysis is required then ISO 7933 provides an analytical method that can provide a more extensive assessment and interpretation leading to recommendations for improvement to the working environment. Where a method needs to be confirmed, or conditions are beyond the scope of ISO 7243 and ISO 7933, then ISO 9886 provides guidance on physiological measurement and interpretation. This would be used in extreme environments where individual responses are required to ensure health and safety or, in the case where personal protective equipment (PPE) is worn, which is beyond the scope of ISO 7243 and ISO 7933. The ISO system therefore covers almost all exposures to hot environments. It would be useful however to extend the scope of the standards that provide a simple index or analytical approach. This paper describes the current standards and their scope and forms the basis and background for descriptions of proposed extensions to the scope of the standards described in other papers in this special issue.

Acclimatization↗
PubMed1999

Clothing evaporative heat resistance--proposal for improved representation in standards and models.

Clothing heat and vapour resistance are important inputs for standards and models dealing with thermal comfort, heat- and cold-stress. A vast database of static clothing heat resistance values is available, and this was recently expanded with correction equations to account for effects of movement and wind on the static value of heat resistance in order to obtain the dynamic heat resistance of clothing ensembles. For clothing vapour resistance, few data were available so far. Indices for vapour permeability (im) and reduction factors for vapour transfer (Fpcl) of clothing were used instead, using a relation between heat and vapour resistance to derive the clothing vapour resistance from the value for clothing heat resistance. This paper reviews the two commonly used approaches (im and Fpcl), as well as five alternative approaches to the problem. The different approaches were evaluated for their accuracy and their usability. The present paper shows that the currently used relations are not adequate when the wearer of the clothing starts moving, or is exposed to wind. Alternative approaches are shown to improve the determination of dynamic clothing vapour resistance, though some are thought to be too complex. An empirical description of the relation between the clothing permeability index (im) and the changes in clothing heat resistance due to wind and movement was selected as the most promising method for deriving clothing vapour resistance. For this method the user needs to know the static heat resistance, the static im value of the clothing and the wind- and movement-speed of the wearer. This method results in a predicted maximal decrease in clothing vapour resistance by 78%, when clothing heat resistance is reduced by 50%, which is consistent with theoretical expectations and available data.

Bias↗
PubMed1999

The effects of wind and human movement on the heat and vapour transfer properties of clothing.

This paper integrates the research presented in the papers in this special issue of Holmér et al. and Havenith et al. [Holmér, I., Nilsson, H., Havenith, G., Parsons, K. C. (1999) Clothing convective heat exchange: proposal for improved prediction in standards and models. Annals of Occupational Hygiene, in press; Havenith, G., Holmér, I., den Hartog, E. and Parsons, K. C. (1999) Clothing evaporative heat resistance: proposal for improved representation in standards and models. Annals of Occupational Hygiene, in press] to provide a practical suggestion for improving existing clothing models so that they can account for the effects of wind and human movement. The proposed method is presented and described in the form of a BASIC computer program. Analytical methods (for example ISO 7933) for the assessment of the thermal strain caused by human exposure to hot environments require a mathematical quantification of the thermal properties of clothing. These effects are usually considered in terms of 'dry' thermal insulation and vapour resistance. This simple 'model' of clothing can account for the insulation properties of clothing which reduce heat loss (or gain) between the body and the environment and, for example, the resistance to the transfer of evaporated sweat from the skin, which is important for cooling the body in a hot environment. When a clothed person is exposed to wind, however, and when the person is active, there is a potentially significant limitation in the simple model of clothing presented above. Heat and mass transfer can take place between the microclimate (within clothing and next to the skin surface) and the external environment. The method described in this paper 'corrects' static values of clothing properties to provide dynamic values that take account of wind and human movement. It therefore allows a more complete representation of the effects of clothing on the heat strain of workers.

Bias↗
PubMed1995

Ergonomics and international standards: history, organizational structure and method of development.

Egonomics international standards were formally considered in 1973 by a symposium of the International Ergonomics Association (IEA) held at Loughborough University in the UK. Recommendations led to the establishment of ISO TC 159 'Ergonomics', with Germany (DIN) holding the secretariat. Six subcommittees (SC) were established and have worked towards standards. These have been rationalized to the present four subcommittees: SC1, Ergonomics guiding principles; SC3, Anthropometry and biomechanics; SC4, Ergonomics and human system interaction; and SC5, Ergonomics of the physical environment. The subcommittees have over 15 working groups (WG) covering over 50 work items that will lead to ergonomics ISO standards. Over 20 ISO standards have already been produced and a number have been reconfirmed at automatic five-yearly reviews. The organizational structure is presented as well as methods of standards production from proposed work item to international standard. European standards (EN) are produced under CEN TC 122 'Ergonomics', which has 11 working groups. How European Standards are produced and organizational links with ISO TC 159 are described.

Journal Article↗
PubMed1995

Ergonomics and international standards: introduction, brief review of standards for anthropometry and control room design and useful information.

The International Organization for Standardization (ISO) coordinates the production of internationally accepted standards, and involves over 100 countries. ISO TC 159 'Ergonomics' was set up in 1975. In 1988, the Comite Europeen De Nomalisation (CEN) established CEN TC 122 'Ergonomics' for the production of European standards. An exhaustive list of standards, proposed standards and work items is provided. Standards in the areas of anthropometry and control room design are presented. Additional useful information is provided in the form of abbreviations and terms and a list of addresses of where to obtain standards.

Journal Article↗
PubMed1995

Ergonomics of the physical environment: international ergonomics standards concerning speech communication, danger signals, lighting, vibration and surface temperatures.

This paper considers standards relevant to environmental ergonomics, and includes those that have been, or are likely to be, produced by the International Organization for Standardization (ISO), under ISO TC 159 SC5 'Ergonomics of the physical environment' and working groups of CEN TC 122 'Ergonomics'. It includes descriptions of standards concerned with speech communication in noisy environments, visual and auditory danger signals, lighting, vibration, skin contact with hot surfaces and others. It is noted that for historical and organizational reasons, some standards relevant to this area are not developed by ergonomics standards committees. The ergonomist can use international standards to ensure use of the best available data and internationally accepted methods. Standards will not determine workplace design but can provide a useful 'starting point' for successful design.

Journal Article↗
PubMed1995

International heat stress standards: a review.

Heat stress indices are included in international standards to provide methods and limits for the design, assessment and control of hot thermal environments. Indices used in standards are described with particular reference to those in ISO standards concerned with the ergonomics of the thermal environment. ISO 7243 provides a simple method for assessing and controlling hot environments based upon the WBGT (web bulb globe temperature) index. ISO 7933 describes an analytical method of assessment of hot environments based upon the human heat balance equation and the calculation of the required sweat rate index (Sreq). This standard is discussed in detail with particular consideration of its use in practical application. The method has been evaluated in both laboratory and industrial contexts. Limitations of the standards and areas where further development is required, are presented.

Body Temperature Regulation↗
PubMed1994

Colorectal cancer incidence in pattern and model makers: evidence from a screening program.

This study is designed to evaluate the efficacy of colorectal cancer screening in a high risk population of pattern and model makers. The cohort of 1,641 white male automotive pattern and model makers was identified in 1981, and offered colorectal cancer screening. The program involved periodic 60 cm flexible sigmoid examination, stool occult blood testing, and digital rectal examination. Screening was offered in 1981, 1982, 1985, 1988, and 1991. Approximately 60% of those eligible participated in at least one screening examination. Nonparticipants showed a relative risk for incident colorectal cancer of over 10, compared to those who participated at least once in the screening. Cohort tracking has accumulated 10 years; results suggest a benefit to colorectal cancer screening in this population.

Adult↗
PubMed1994

Using computer-based models for predicting human thermal responses to hot and cold environments.

Four influential models, capable of predicting human responses to hot and cold environments and potentially suitable for use in practical applications, were evaluated by comparing their predictions with human data published previously. The models were versions of the Pierce Lab 2-node and Stolwijk and Hardy 25-node models of human thermoregulation, the Givoni and Goldman model of rectal temperature response, and ISO/DIS 7933. Experimental data were available for a wide range of environmental conditions, with air temperatures ranging from -10 to 50 degrees C, and with different levels of air movement, humidity, clothing and work. The experimental data were grouped into environment categories to allow examination of the effects of variables, such as wind or clothing, on the accuracy of the models' predictions. This categorization also enables advice to be given regarding which model is likely to provide the most accurate predictions for a particular combination of environmental conditions. Usually at least one of the models was able to give predictions with an accuracy comparable with the degree of variation that occurred within the data from the human subjects. The evaluation suggests that it is possible to make useful predictions of deep-body and mean skin temperature responses to cool, neutral, warm and hot environmental conditions. The models' predictions of deep-body temperature in the cold were poor. Overall, the 25-node model provided the most consistently accurate predictions. The 2-node model was often accurate but could be poor for exercise conditions. The rectal-temperature model usually overestimated deep-body temperature, although its predictions for very hot or heavy exercise conditions could be useful. The ISO model's allowable exposure times would not have protected subjects for some exercise conditions.

Body Temperature Regulation↗
PubMed1991

Rehabilitation in spinal cord disorders. 3. Comprehensive management of spinal cord injury.

This self-directed learning module highlights advances in the management of the person with a spinal cord deficit. Traumatic spinal cord injury is being used as the model, but the principles apply to all patients with spinal cord deficits. This article is part of the chapter on rehabilitation of spinal cord disorders for the Self-Directed Medical Knowledge Program Study Guide for practitioners and trainees in physical medicine and rehabilitation. Specifically, this section contains information regarding prehospital care, acute assessment and management, primary rehabilitation by systems, sexuality and psychosocial issues, management of pain and spasticity, functional goals, the role of functional electrical stimulation, and long-term follow-up.

Humans↗