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Commercial grain elevators are hazardous agro-manufacturing work environments where workers are prone to serious and life-threatening injuries. The aim of this study is to give insight into safety risks in grain handling facilities through information processing of workers’ compensation data on agro-manufacturing occupational incidents within commercial grain elevators in the Midwest region of the United States between 2008 and 2016. The severity of occupational incidents is determined by total dollar amount incurred on medical, indemnity, and other expenses in workers’ compensation claims. The most important factors that affect the cost escalation of occupational incidents are extracted using bootstrap partitioning method, and are applied as input for constructing two machine learning models: random forests decision trees, and naive Bayes. Both models show high accuracy (87.64% and 92.78% respectively) in predicting that a future claim is classified as either low or medium, severity. The models contribute to identifying high injury risk groups, and prevalent incident causes, allowing a more research-based focused intervention effort in grain handling workplaces. In addition, the results are applicable in forecasting cost severity of future claims, and identifying factors that contribute to the escalation of claims costs.

Creating safe work environment is significant in saving workers’ lives, improving corporates’ social responsibility and sustainable development. Pattern identification in occupational accidents is vital in elaborating efficient safety counter-measures aiming at improving prevention and mitigating outcomes of future incidents. The objective of this study is to identify patterns related to the occurrence of occupational accidents in non-farm agricultural work environments based on workers’ compensation claims data, using latent class clustering method as an un-supervised machine learning modeling approach. The result showed injury profiles and incident dynamics have low, average, and high levels of risks based on the main causes and outcomes of the injuries and the affected body part(s).

Although machine learning methods have been used as an outcome prediction tool in many fields, their utilization in predicting incident outcome in occupational safety is relatively new. This study tests the performance of machine learning techniques in modeling and predicting occupational incidents severity with respect to accessible information of injured workers in agribusiness industries using workers’ compensation claims. More than 33,000 incidents within agribusiness industries in the Midwest of the United States for 2008–2016 were analyzed. The total cost of incidents was extracted and classified from workers’ compensation claims. Supervised machine learning algorithms for classification (support vector machines with linear, quadratic, and RBF kernels, Boosted Trees, and Naive Bayes) were applied. The models can predict injury severity classification based on injured body part, body group, nature of injury, nature group, cause of injury, cause group, and age and tenure of injured workers with the accuracy rate of 92–98%. The results emphasize the significance of quantitative analysis of empirical injury data in safety science, and contribute to enhanced understanding of injury patterns using predictive modeling along with safety experts’ perspectives with regulatory or managerial viewpoints. The predictive models obtained from this study can be used to augment the experience of safety professionals in agribusiness industries to improve safety intervention efforts.

A new and transformational gas lift method termed Liquid Assisted Gas Lift (LAGL) has been developed. LAGL utilizes the co-injection of liquid with lift gas to reduce surface pressure requirements for the kick-off of gas lift, simplify well completions and improve system reliability/flexibility. PetroleumETC executed a Shell GameChanger project to demonstrate the delivery of LAGL for well unloading and kick-off of gas lift. Qualification testing was performed at a university test facility utilizing a 2,788 ft TVD test well with 5 ½-inch casing and 2 7/8-inch tubing. Air and water were the test media. In-well measurements were available bottomhole and mid-string for both the annulus and the tubing. The test well was successfully unloaded in 2 hours with a maximum pressure of 535 psig using manual operation of the module. Two automated tests were successfully conducted; one requiring 2 hours (670 psig max pressure) and one requiring 1 hr and 24 min (724 max pressure). Many lessons were learned, effectively de-risking the technology for field application. A new sliding-sleeve orifice valve was also tested with water, air and under multiphase flow conditions. The larger orifice sizes provided by the 2 7/8-inch sliding sleeve slim valve provides for faster unloading using the LAGL process. The paper provides an update on advances in the value case for the new LAGL technology. LAGL utilizes a single G-L valve, which reduces system costs versus the traditional use of multiple G-L valves and mandrels and dramatically reduces the risk of multi-pointing. LAGL provides the advantage of High-Pressure Single Point Gas Lift (HPSPGL) without the need for high pressures on the well pad, changing surface piping and a high pressure compressor.

This study addresses the safety portion of the National Association of Industrial Technology (NAIT) Certification exam. NAIT promotes the field of industrial technology in education, business, and industry. Certification is the recognition of voluntarily achieved standards by the profession that created the proposed standards. Certification programs are used to define a required body of knowledge and skills, and establish common performance standards. The NAIT certification exam began its initial development in the 1990s. Since its development, the safety portion of the certification exam has not been reevaluated critically. A survey with an expert panel was used to determine if the safety content of the NAIT certification exam was still appropriate. Participants, made up of members of the NAIT Safey Division, identified 30 safety topics as being important enough to be represented in the safety portion of the NAIT certification exam. This study concluded that while terminology may have changed slightly, the safety topics covered on the NAIT certification exam are still relevant and current. Introduction NAIT is a professional membership organization dedicated to the establishment and maintenance of professional standards for industrial technologists, and the certification program was established to acknowledge an individual’s knowledge, skills, and professional development in the field of industrial technology (Field & Rowe, 2001). The NAIT certification exam was initially developed in the 1990s under the direction of Dr. Clois Kicklighter using a Delphi method to determine the appropriate content for the exam. The Delphi method was used to collect data from the various academic institutions across the United States that had industrial technology programs, without bringing participants to one central location. Three iterations of the Delphi process were conducted. The results of the study were reported internally to NAIT in October 1991. Eight major exam content areas were identified from that study: (1) Quality Control; (2) Production Planning and Control; (3) Industrial Supervision; (4) Industrial Finance and Accounting; (5) Industrial Safety Management; (6) Plant Layout and Materials Handling; (7) Time and Motion Study; and (8) Industrial Communications (C. Kicklighter, personal communication, October 10, 1991). These eight content areas were reduced to six by eliminating “Industrial Finance and Accounting” and “Plant Layout and Materials Handling” as stand-alone content areas during the initial developmental cycle of the exam between October 1993 and March 1995. Ultimately, the number of stand-alone content areas was reduced to four by dropping “Time and Motion Study” and “Industrial Communications” as stand-alone areas during final pretesting of the exam. The remaining areas of concentration included: (1) Production Planning and Control, (2) Quality Control, (3) Safety, and (4) Supervision/Administration. A modified Delphi method was used by Rowe (2001) in her efforts to identify core content, subject area, and competency information needed to update Dr. Steven A. Freeman is an associate professor in the Agricultural and Biosystems Engineering Department and assistant director of the Center for Excellence in Learning and Teaching at Iowa State University. He coordinates the occupational safety option of the industrial technology degree program for the department and serves as the director for graduate education. His research interests are in agricultural and workplace safety and the scholarship of teaching and learning associated with safety, engineering, and technology curricula. Dr. Dennis W. Field is an Associate Professor and Coordinator of the Graduate and Undergraduate Industrial Technology programs in the Department of Technology at Eastern Kentucky University. He has been actively involved in the development of the NAIT Certification exam and served as Chair of the National Association of Industrial Technology Board of Certification for nine years. His research interests are in high-technology manufacturing start-up and transfer activities. Ms. Chandra Lott is a former graduate student of Iowa State University where she received her Masters of Science degree in Industrial Education & Technology with an emphasis in occupational safety. She is currently pursuing a career in her chosen field of study. Dr. Charles V. Schwab is a professor in the Agricultural and Biosystems Engineering Department and an Iowa State University Extension specialist in farm safety. He provides leadership for Safe Farm, an Iowa State University (ISU) Extension’s program helping to make Iowa farms a safer place to work and live. Dr. Schwab serves as the Iowa State University point of contact for the Extension Disaster Education Network (EDEN). He is also the professor in charge of the Safety Training Instruction and Research Center at Iowa State University.

Agribusiness industries are among the most hazardous workplaces for non-fatal occupational injuries. The term &ldquo, post-incident state&rdquo, is used to describe the health status of an injured person when a non-fatal occupational injury has occurred, in the post-incident period when the worker returns to work, either immediately with zero days away from work (medical state) or after a disability period (disability state). An analysis of nearly 14,000 occupational incidents in agribusiness operations allowed for the classification of the post-incident state as medical or disability (77% and 23% of the cases, respectively). Due to substantial impacts of occupational incidents on labor-market outcomes, identifying factors that influence the severity of such incidents plays a significant role in improving workplace safety, protecting workers, and reducing costs of the post-incident state of an injury. In addition, the average costs of a disability state are significantly higher than those of a medical state. Therefore, this study aimed to identify the contributory factors to such post-incident states with logistic regression using information from workers&rsquo, compensation claims recorded between 2008 and 2016 in the Midwest region of the United States. The logistic regression equation was derived to calculate the odds of disability post-incident state. Results indicated that factors influencing the post-incident state included the injured body parts, injury nature, and worker&rsquo, s age, experience, and occupation, as well as the industry, and were statistically significant predictors of post-incident states. Specific incidents predicting disability outcomes included being caught in/between/under, fall/slip/trip injury, and strain/injury by. The methodology and estimation results provide insightful understanding of the factors influencing medical/disability injuries, in addition to beneficial references for developing effective countermeasures for prevention of occupational incidents.

The development and adoption of promotion and tenure (P&T) policies supporting scholarship of teaching and learning (SoTL) activities began in earnest at our large, Midwestern, land-grant university, over fifteen years ago. The purpose of this research was to present the results of a five year project collecting and analyzing the evidence of SoTL on P&T vitas. Every occurrence of SoTL in peer-reviewed publications, presentations, and funded external and internal grants was counted. Of the 343 successful cases, there were 201 to associate professor and 142 to professor. Of these cases, 48% (n=163) had at least one SoTL artifact included on their vitas. These results suggest SoTL is a meaningful form of scholarship performed by faculty, however, there is additional cultural change necessary for greater integration of SoTL in faculty work.

Insurance practitioners rely on statistical models to predict future claims in order to provide financial protection. Proper predictive statistical modeling is more challenging when analyzing claims with lower frequency, but high costs. The paper investigated the use of predictive generalized linear models (GLMs) to address this challenge. Workers&rsquo, compensation claims with costs equal to or more than US$100,000 were analyzed in agribusiness industries in the Midwest of the USA from 2008 to 2016. Predictive GLMs were built with gamma, Weibull, and lognormal distributions using the lasso penalization method. Monte Carlo simulation models were developed to check the performance of predictive models in cost estimation. The results show that the GLM with gamma distribution has the highest predictivity power (R2 = 0.79). Injury characteristics and worker&rsquo, s occupation were predictive of large claims&rsquo, occurrence and costs. The conclusions of this study are useful in modifying and estimating insurance pricing within high-risk agribusiness industries. The approach of this study can be used as a framework to forecast workers&rsquo, compensation claims amounts with rare, high-cost events in other industries. This work is useful for insurance practitioners concerned with statistical and predictive modeling in financial risk analysis.

The safety climate of an agricultural workplace may be affected by several things, including the level of trust that workers have in their work group supervisor and organizational management. Safety climate has been used by previous safety researchers as a measure of worker perceptions of the relative importance of safety as compared with other operational goals. Trust has been linked to several positive safety outcomes, particularly in hazardous work environments, but has not been examined relative to safety climate in the perennially hazardous work environment of a commercial grain elevator. In this study, 177 workers at three Midwest grain elevator companies completed online surveys measuring their perceptions of trust and safety at two administrative levels: organizational management and work group supervisors. Positive and significant relationships were noted between trust and safety climate perceptions for organizational managers and for work group supervisors. Results from this research suggest that worker trust in organizational management and work group supervisors has a positive influence on the employees' perceptions of safety climate at the organizational and work group levels in an agricultural workplace.

Safety training is an important part of every safety professional's daily practice. Evaluation of the effectiveness of safety training is especially critical. A research study was undertaken that first explores the basics of devising an effective safety training module. The literature related to the key issues of amount of learning and retention is reviewed and tested in the context of a site-specific chemical safety training course that is offered both in the classroom and on the computer. The importance of evaluating characteristics of the learner is discussed and evaluated. Finally, important variables related to assessment technique (i.e., how learning is assessed) are discussed. The results of the study confirm that training participants were getting equivalent learning experiences regardless of the training methodology (classroom versus computer). Numerous learner characteristics were evaluated relative to both learning and retention and were found to have no impact on the observed results. The implications of the findings of this study are discussed relative to potential impact on an overall safety training program. Not only is it essential to evaluate the effectiveness of safety training given different delivery methodologies, but the techniques used are relatively simple and can facilitate reductions in overall costs associated with training.

The study explored the influence of work experience on adult part-time students’ academic success as defined by their cumulative grade point average. The sample consisted of 614 parttime students from four polytechnic institutions in Malaysia. The study identified six factors to measure the perceived influence of work experiences—positive belief, negative belief, intrinsic motivation, learning orientation, deep learning approach, and surface learning approach. The results indicated that lower academic success was associated with higher negative belief, lower intrinsic motivation and adopting surface learning approach. Students with a deeper learning approach, greater intrinsic motivation, and greater learning orientation tended to perceive higher positive belief. In contrast, students who favored surface learning approaches were more likely to perceive negatively the impact of work experiences on their academic learning. The best-fitted path model demonstrated students’ academic success was affected negatively by negative belief and weakly by intrinsic motivation. Other factors did not have significant direct effects on students’ academic success. These findings suggest that the success of adult part-time students does not rely on their positive attitude alone, but also could depend on the effectiveness of the classroom environment, teaching and learning strategies, and assessment methods.

The use of biotechnology in food and agricultural applications has increased greatly during the past decade and is considered by many to be a controversial topic. Drawing upon a previous national study, a new survey was conducted of U.S. and international college students at a large, land-grant, Research University to determine factors that may affect opinions about genetically modified (GM) food products. Factors examined included nationality, discipline area of study, perceptions of safety, and awareness and levels of acceptance regarding GM food. Results indicated students born outside the United States had more negative opinions about genetically modified foods than did American-born students. Students who were studying a physical science-based curriculum had a more positive opinion of GM food than did students studying a curriculum that was not based in the physical science. In addition, students who reported a higher level of acceptance of genetically modified foods felt more positively about the safety of the technology.

Establishing the relationship between level of safety climate and safety performance is a current challenge. This work examines the relationship between level of safety climate and orientation toward safety in the decision making process and choice. Alternatively, this work seeks to answer the question of whether level of safety climate can predict safety-oriented decision making. A generalized safety climate questionnaire and a decision making simulation are utilized to examine this relationship. The results indicate that level of safety climate is not a significant predictor of the decision process; however, it was found to be a significant predictor of the selection of safer choices.

According to the United States Department of Transportation (USDOT), more than 3.1 billion tons of hazardous materials (HazMat) are shipped within the United States annually. This averages to about 800,000 individual shipments of HazMat per day, of which 300,000 are shipments of petroleum/flammable–combustible liquids. This paper presents a temporal trend study (1995–2004) of 2145 HazMat incidents occurring through the transportation of flammable/combustible liquids. The study also correlates between HazMat incidents and distances between shipment origin and incident location. These distances attained through great circle calculations since the data compilation did not allow for the identification of specific routes taken in commodity transport. Findings of this study illustrate a bimodal distribution of frequency as a function of the logarithm of the Distance with first mode (less than 105 miles) mean of 24 [km] and second mode mean of 1061 [km]. Additionally, transport phase introduced no significance to the distribution of frequencies.

This study explored how workplace competency assessment data collected by College of Engineering programs from internship students and their supervisors between fall 2001 through fall 2011, are applied toward continuous improvement practices. The continuous improvement process is integral to the accreditation and evaluation of the engineering curriculum. This mixed methods study examined three separate practices using internship workplace competency assessment ratings in the continuous improvement process. The study examined how assessment rankings of the internship students’ workplace competency strengths and weakness have changed from the 2001-05 assessment terms in the past accreditation cycle, to the 2006-11 assessment terms of the most recent accreditation cycle. It examined competency achievement percentages related to the ABET Criterion 3 (a-k) outcomes across the same timeline, and investigated how workplace competency assessment data are used to support continuous improvement for program curricula in the College of Engineering. The intent of the study was to gain better understanding of how the workplace competency assessment data has benefited the continuous improvement process that enhances student learning. The results can also provide suggestions to programs in the early stages of developing new program evaluation techniques.

The article examines the organizational resilience shown by Sandler O'Neill & Partners L.P. after losing employees and assets during the September 11, 2001 terrorist attacks. Several situational fa...

Research studies have shown that tractor rollovers are the leading cause of work-related death in U.S. production agriculture. Previous studies have also shown that while rollover protective structures (ROPS) are the most effective means of preventing these deaths, it is estimated that over half of the tractors in use on U.S. farms are not equipped with ROPS. To gauge the impact of a ROPS retrofit policy, tractor sales in Central Iowa were monitored for a three-month period in early 1998 to determine the proportion of tractors without ROPS being sold by equipment dealers versus those being sold through other channels such as auctions, farm sales, and private transfer. During the study period, 549 tractors sales were documented in Central Iowa. Of these tractors, 72% were equipped with ROPS. Of the 152 that were sold without ROPS, 43% were sold by equipment dealers. ROPS retrofits were readily available for 92% of the tractors that were not equipped with them at the time of the sale. A fully implemented ROPS retrofit program for equipment dealers would have reduced the number of tractors sold without ROPS in Central Iowa by over 40%. The results suggest that such a policy could have a significant impact in reducing the number of farm fatalities and thus should be investigated further.

Seventy-one cases of entrapment in various bulk agricultural materials at commercial grain facilities were identified during the period from 1969 through 1995 in 25 states and the province of Ontario. The present annual rate of five fatal entrapments in the commercial grain industry is estimated to be 4.3 per 10,000 facilities. While fatal entrapments appear to be relatively rare events compared to other work-related fatalities associated with the grain-handling industry, the morbidity of entrapment victims is extremely high. In fact, 92% of the complete entrapments identified resulted in a fatality. As with farm-related grain entrapments and suffocations, entrapments in commercial facilities tend to occur in the Corn Belt and involve out-of-condition grain, primarily corn. The data gathered in this study also suggest that employees become entrapped when they are circumventing safe work practices and that an employee working alone is unlikely to survive the entrapment. It is also clear that current injury surveillance mechanisms do not provide adequate information to develop comprehensive prevention and first response strategies for the commercial grain industry.

A survey of Indiana farm homes was conducted in the winter of 1994-1995 to establish realistic baselines concerning child safety practices for populations in rural Indiana for the purpose of: (1) adjusting interventions to target specific issues where prevention efforts are most needed; and (2) evaluating the effectiveness of safety efforts targeting rural Indiana families. A questionnaire was designed to obtain baseline information for child safety practices on Indiana farms, and a stratified random sample of 1,500 Indiana farms (arrayed by county) was selected from a population consisting of all 60,000 Indiana farms. Survey procedures involved two mailings, and phone interviews with non-respondents, which yielded 597 usable questionnaires. Survey responses indicate that on Indiana farms where children reside or frequently visit, 63% of owner/operators allow children to ride as passengers on tractors and/or combines, and 36% allow children to operate tractors. Survey responses suggest that grandparents are more likely than parents to prohibit potentially dangerous farm activities (e.g., riding on tractors, combines, and grain transport vehicles, and operating tractors and ATVs), while parents are more likely to implement strategic safety practices (e.g., having a fire escape plan, and obtaining CPR/first aid training). Survey results also show that Indiana farm families do not meet national goals for the use of bicycle helmets, child seats/seatbelts, or smoke detectors.

Human factors play an important role in the management of safety and quality in an agricultural work environment. Although employee actions and decisions have been identified as a key component of successful occupational safety programs and quality management programs, little attention has been given to the employees' role in these types of programs. This research explored two safety relationships that have theoretical connections but little previous research: the relationship between safety climate and quality climate, and the relationship of the safety and quality climates between the organizational level and the group level within a workplace. Survey data were collected at three commercial grain handling facilities from 177 employees. Employees also participated in safety and quality decision-making simulations. Significant positive predictions were noted for safety and quality climate. Decision-making predictions are also discussed. This research suggests that organizational safety is an important predictor of group safety. In addition, recognizing the larger role that supervisors play in group workplace behavior, more should be done to increase employee perceptions of group-level involvement in quality climate to promote more quality-oriented decision-making by employees.

A central challenge for higher education today is to understand the diversity and complexity of nontraditional students’ life experiences and how these factors influence their academic success. To better understand these issues, this study explored the role of demographic characteristics and employment variables in predicting the academic success of part-time students at four polytechnic institutes in Malaysia. Demographic characteristics studied included respondent’s age, gender, marital status, number of children, parent’s educational level, and financial resources. Employment variables assessed were number of years working, job relatedness to the program, job satisfaction, and monthly salary. A total of 614 part-time students completed the survey. Results indicated that being an older student, being female, paying for their own education, and having high job satisfaction were statistically significant predictors of part-time students’ academic success. Understanding the effects of demographic characteristics and employment variables on students’ academic success might help administrators and educators to develop teaching and learning processes, support services, and policies to enhance part-time students’ academic success.

Resources and expertise on selecting assistive technology appropriate for an agricultural work setting are scarce. To meet this need a prototype knowledge system for the selection and documentation of rural assistive technology (BNG DATA) was developed to aid professionals working with farmers, ranchers, and agricultural workers with physical disabilities. The knowledge system consists of a hypertext database of technology examples and a decision support system that helps users identify solution alternatives to meet consumers' needs. End-user acceptance of BNG DATA was determined through field trials and an evaluation questionnaire administered to staff of the U.S. Department of Agriculture's AgrAbility Project. Using a statistical experiment in conjunction with the questionnaire, it was concluded that BNG DATA significantly reduced the time required by end users to find acceptable solution alternatives for consumers and increased the end users' confidence in the solutions they obtained. This manuscript describes the development and testing of BNG DATA, focusing on the selection of appropriate technology.

A prototype hypermedia decision support system for the selection and documentation of rural assistive technology (BNG DATA) was developed to aid professionals working with farmers, ranchers, and agricultural workers with physical disabilities. The hypermedia system (constructed using HyperCard, an environment that combines hypertext and database features) consists of a hypermedia database of rural assistive technology examples and an accompanying decision support system that helps users identify solution alternatives to meet the needs of their clientele. End user acceptance of BNG DATA was determined using an evaluation questionnaire. The end users evaluating the prototype considered BNG DATA to be easy to learn, easy to use, and unanimously considered BNG DATA to be a valuable resource that they would like to have for their own use. Using a statistical experiment in conjunction with the questionnaire, it was also concluded that BNG DATA significantly reduced the amount of time required by end users to find acceptable solution alternatives for their clientele (a = 0.01) and increased the end users’ confidence in the solutions they obtained (a = 0.10). This article describes the development and testing of BNG DATA, focusing on the steps taken to ensure end user acceptance.

Introduction A common contention is that the construction of highway bypasses negatively impacts the economy of local communities by reducing pass-by traffic for businesses. However, as access to specific business' account records is limited, this impact is difficult to quantify. Another common contention is that bypasses contribute to a reduction in overall crashes in the community and in the surrounding areas. Even though a large number of bypasses have been constructed in the State of Iowa over the past several years, their actual impact in terms of traffic safety has not been quantified. Objectives This study seeks answers to the following questions: (a) Are bypasses in Iowa associated with a reduction in crash frequencies and crash rates on the bypassed highway? (b) Do bypasses in Iowa introduce a reduction of overall crash frequencies and rates or do they merely shift crashes from the highways through the communities to the bypasses with no significant overall reduction? Method We obtained crash information from the Iowa DOT at 19 sites on which a bypass was constructed sometime during the past 23 years. We also obtained the same information at six sites used as comparison sites on which no bypasses were constructed at least until 2005. We them employed a Bayesian approach to estimating the association between the construction of the bypass and crash rates, while also accounting for other factors. Results The construction of bypasses in Iowa is associated with a significant increase in traffic safety both on the main road through town and on the combined main road and bypass roadway.

— Ultraviolet radiation produces erythema in human skin, and damages the DNA of living cells in skin. Previous work showed that broad-band UV-B (290–320 nm) radiation produced higher levels of cyclobutyl pyrimidine dimers in DNA of individuals with high UV-B sensitivity (low minimal erythema dose) than in subjects of low UV-B sensitivity [Freeman et al. (1986) J. Invest. Dermatol., 86, 34–36]. We examined the relationship between erythema induction and dimer yields in DNA of human skin irradiated in situ with narrow band radiation spanning the wavelength range 275–365 nm. We find that, in general, higher dimer yields are produced per incident photon in volunteers with higher susceptibility to erythema induced by radiation of the same wavelength.

In order to identify events/activities that are particularly stressful for farmers/ranchers, a farm stress survey based on the proportionate scaling method was mailed to a stratified random sample of 3,000 Iowa farmers by the USDA National Agricultural Statistics Service. The participants were asked to compare 62 life events and farm activities to a marriage (assigned a baseline rating of 50), decide if it was less stressful or more stressful, and then assign a stress rating between 1 and 100. As expected, the most stressful events were the death of a spouse or child. Other high-stress events were disabling injuries, foreclosure on a mortgage, divorce, machinery breakdown during harvest, and loss of crop to weather. Mean stress ratings varied by age, marital status, and type of farming enterprise. Farmers between the ages of 40-59 and 60-79 had the most items with high stress levels. Females had more high-stress items than males. Divorced farmers had fewer high-stress items than other respondents. Farmer's whose primary focus was raising horses had more high-stress items than other farm types. Significant outcomes of this study go beyond the specific mean stress ratings of the events and activities. The results indicate that farm stressors can be quantified using the proportionate scaling method and that the impact of the stressor is based not just on the event but is also dependent on the characteristics of the farmer (e.g., age, gender, marital status, etc.).

Delta-sigma (/spl Delta//spl Sigma/) modulators can implement a simpler digital ultrasound beamformer than can traditional architectures based on multi-bit analog-to-digital converters (A/D). The signal-to-noise ratio (SNR) of the /spl Delta//spl Sigma/ modulators, however, suffers from limited oversampling ratios. To improve the SNR of each channel, a mixing signal heterodynes narrowband signals to lower frequencies where the baseband /spl Delta//spl Sigma/ modulator performs better. Noise figure analyses are presented that illustrate the effectiveness of this technique in improving noise performance. Also, spectral Doppler and color flow simulations are presented that realistically emulate a 32 channel oversampled beamformer and compare these results with traditional and ideal systems.

The principles of oversampling are exploited in a simple beamforming architecture using a single bit delta-sigma (/spl Delta/C) analog to digital converter (A/D) on every channel. The high sampling rate required for the single bit A/D provides adequate delay accuracy for high quality beamforming using elementary sample manipulations. Images produced with this beamformer exhibit significant artifacts directly related to dynamic focusing. However, a simple digital recording technique following delays permits dynamically focused beamforming without degrading image quality. The simplicity of this beamformer compared to conventional methods may facilitate very large channel count or low power beamformers suitable for 1.5-D arrays or portable scanners.

Prior research demonstrated that writing synopsis laboratory reports (succinct syntheses of the experiment, lecture, and readings) instead of traditional laboratory reports, did not influence student learning as measured by comprehensive exam scores. This study extended this research by investigating the impact of these lab report formats on student learning as measured by laboratory report scores. Fifty-six Iowa State University industrial technology students were randomized into one of two groups that were required to write five synopsis reports followed by four traditional reports or vice-versa. The analysis of mean laboratory report scores using the paired-samples t-test revealed no significant difference between treatments. The analysis of the mean scores of the nine individual laboratory reports using two-sample t-tests revealed no treatment effect for seven of the nine reports. The results of an exit survey revealed that students believed the synopsis format helped them to achieve higher grades on their laboratory reports.

A previous report [Freeman et al. (1986) Photochem. Photobiol. 43S, 93S] indicated that irradiation of human skin in situ with 385 or 405 nm radiation produced detectable levels of pyrimidine dimers in DNA. Since these wavelengths are absorbed poorly by DNA, these results suggested that DNA damage was sensitized by other absorbing molecules present in skin. Examination of two experimental aspects of the previous work indicates that (1) the static gel electrophoresis method for DNA dispersion used in lesion determination gave accurate values of the levels of induced dimers, and (2) the DNA damage apparently induced by 385 nm was actually induced by shorter wavelength UV present in the 20 nm bandpass beam of the monochromator. The current results indicate that monochromatic 385 and 405 nm radiation are ineffective in dimer production in human skin in situ.

Ultraviolet excimer lasers are being considered for use in a variety of refractive and therapeutic procedures, the long-term biologic consequences of which are unknown. The effect of sublethal doses of 193-nm laser radiation on cellular DNA was examined in cultured human skin fibroblasts. In contrast to 248 nm, treatments with the 193-nm laser radiation below 70 J/m2 did not cause significant pyrimidine dimer formation in the skin cells. This was indicated by the lack of excision repair activities (unscheduled DNA synthesis assay), and further demonstrated by direct analysis of pyrimidine dimers in DNA from irradiated cells. However, a low level of unscheduled DNA synthesis could be detected following irradiation at 193 nm with 70 J/m2. Both the 193-nm and 248-nm radiation were able to induce chromosomal aberrations, as indicated by a micronucleus assay. A dose-dependent increase in micronuclei frequency was observed 48 and 72 h after laser irradiation. These results indicate that exposure of actively replicating human skin fibroblasts to sublethal doses of either 193- or 248-nm laser radiation can result in genotoxicity.

We have compared video and photographic methods for calculating the number of ultraviolet radiation (uv)-induced pyrimidine dimers in DNA from the bacteriophage T7 exposed to uv (0 to 800 J/m2) from an FS40 sunlamp. DNA was incubated with a pyrimidine dimer-specific Micrococcus luteus uv endonuclease, subjected to alkaline agarose gel electrophoresis, neutralized, and stained with ethidium bromide, and the DNA fluorescence was recorded either with a video camera or on photographic film. The slopes of the dose-response curves for the number of uv-endonuclease-sensitive sites per 10(3) bases (pyrimidine dimers) was 1.2 (+/- 0.1) X 10(-4) uv-endonuclease-sensitive sites per J/m2 for the video analysis and 1.3 (+/- 0.04) X 10(-4) uv-endonuclease-sensitive sites per J/m2 for the photographic analysis. Results for pyrimidine dimer determination by either method were statistically comparable.