Influence of methylmercury from tributary streams on mercury levels in Savannah River Asiatic clams.

Average methylmercury levels in five Savannah River tributary streams, sampled 11 times over 2 years (0.170 ng/l), were nearly twice as high as in the Savannah River (0.085 ng/l). Total mercury levels in the tributaries (2.98 ng/l) did not differ significantly from the river (2.59 ng/l). All of the tributaries drained extensive wetlands that would be expected to support comparatively high rates of methylation. Mercury concentrations in Asiatic clams (Corbicula fluminea) collected from the discharge plumes of Savannah River tributaries (average of 0.044 microg/g wet weight) were significantly (P<0.001) higher than in Asiatic clams collected from the Savannah River upstream from the tributary mouths (average of 0.017 microg/g wet weight). These results indicate that streams draining wetlands into coastal plain rivers can create localized areas of elevated methylmercury with resulting increases in the mercury levels of river biota.

Influences on mercury bioaccumulation factors for the Savannah River.

Mercury TMDLs (Total Maximum Daily Loads) are a regulatory instrument designed to reduce the amount of mercury entering a water body and ultimately to control the bioaccumulation of mercury in fish. TMDLs are based on a BAF (bioaccumulation factor), which is the ratio of methyl mercury in fish to dissolved methyl mercury in water. Analysis of fish tissue and aqueous methyl mercury samples collected at a number of locations and over several seasons in a 118-km reach of the Savannah River demonstrated that species-specific BAFs varied by factors of three to eight. Factors contributing to BAF variability were location, habitat, and season-related differences in fish muscle tissue mercury levels and seasonal differences in dissolved methyl mercury levels. Overall (all locations, habitats, and seasons) average BAFs were 3.7 x 10(6) for largemouth bass, 1.4 x 10(6) for sunfishes, and 2.5 X 10(6) for white catfish. Determination of representative BAFs for mercury in fish from large rivers necessitates collecting large and approximately equal numbers of fish and aqueous methyl mercury samples over a seasonal cycle from the entire area and all habitats to be represented by the TMDL.

The science of training: a decade of progress.

This chapter reviews the training research literature reported over the past decade. We describe the progress in five areas of research including training theory, training needs analysis, antecedent training conditions, training methods and strategies, and posttraining conditions. Our review suggests that advancements have been made that help us understand better the design and delivery of training in organizations, with respect to theory development as well as the quality and quantity of empirical research. We have new tools for analyzing requisite knowledge and skills, and for evaluating training. We know more about factors that influence training effectiveness and transfer of training. Finally, we challenge researchers to find better ways to translate the results of training research into practice.

Teamwork in multi-person systems: a review and analysis.

As the scope and complexity of modern task demands exceed the capability of individuals to perform, teams are emerging to shoulder the burgeoning requirements. Accordingly, researchers have striven to understand and enhance human performance in team settings. The purpose of this review is to summarize that research, from the theoretical underpinnings that drive it, to the identification of team-level elements of success, to the methodologies and instruments that capture and measure those characteristics. Further specified are three important avenues to creating successful teams: team selection, task design and team training. In other words, one can select the right people, provide them with a task engineered for superior performance and train them in the appropriate skills to accomplish that task. Under task design, new technologies and automation are examined that both support and impede team functioning. Finally, throughout are provided critical remarks about what is known about teamwork and what is needed to be known to move the science and practice of team performance forward. The paper concludes with the identification of team issues that require further investigation.

The utility of event-based knowledge elicitation.

The purpose of this investigation was to describe and evaluate an event-based knowledge elicitation technique. With this approach experts are provided with deliberate and controlled job situations, allowing investigation of specific task aspects and the comparison of expert responses. For this effort a videotape was developed showing an instructor pilot and student conducting a training mission. Various job situations were depicted in the video to gather information pertinent to understanding team situational awareness. The videotape was shown to 10 instructors and 10 student aviators in the community, and responses to the videotape were collected using a questionnaire at predetermined stop points. Consistent with expectations, the results showed that more experienced respondents (i.e., instructors) identified a richer database of cues and were more likely than students to identify strategies for responding to the situations depicted, providing some empirical evidence for the validity of the event-based technique. This method may serve as a useful knowledge elicitation technique, especially in the later stages of a job analysis when focused information is sought.

Measuring team knowledge.

Multioperator tasks often require complex cognitive processing at the team level. Many team cognitive processes, such as situation assessment and coordination, are thought to rely on team knowledge. Team knowledge is multifaceted and comprises relatively generic knowledge in the form of team mental models and more specific team situation models. In this methodological review paper, we review recent efforts to measure team knowledge in the context of mapping specific methods onto features of targeted team knowledge. Team knowledge features include type, homogeneity versus heterogeneity, and rate of knowledge change. Measurement features include knowledge elicitation method, team metric, and aggregation method. When available, we highlight analytical conclusions or empirical data that support a connection between team knowledge and measurement method. In addition, we present empirical results concerning the relation between team knowledge and performance for each measurement method and identify research and methodological needs. Addressing issues surrounding the measurement of team knowledge is a prerequisite to understanding team cognition and its relation to team performance and to designing training programs or devices to facilitate team cognition.

The influence of shared mental models on team process and performance.

The influence of teammates' shared mental models on team processes and performance was tested using 56 undergraduate dyads who "flew" a series of missions on a personal-computer-based flight-combat simulation. The authors both conceptually and empirically distinguished between teammates' task- and team-based mental models and indexed their convergence or "sharedness" using individually completed paired-comparisons matrices analyzed using a network-based algorithm. The results illustrated that both shared-team- and task-based mental models related positively to subsequent team process and performance. Furthermore, team processes fully mediated the relationship between mental model convergence and team effectiveness. Results are discussed in terms of the role of shared cognitions in team effectiveness and the applicability of different interventions designed to achieve such convergence.

Role of cytokines in the mechanism of action of amlodipine: the PRAISE Heart Failure Trial. Prospective Randomized Amlodipine Survival Evaluation.

OBJECTIVES: We sought to determine whether the beneficial effects of amlodipine in heart failure may be mediated by a reduction in tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) levels. We postulated that TNF-alpha and IL-6 levels may also have predictive value in patients with congestive heart failure (CHF). BACKGROUND: The molecular mechanism for progression of CHF may involve cytokine overexpression. The effect of amlodipine on cytokine levels in patients with CHF is unknown. METHODS: In the Prospective Randomized Amlodipine Survival Evaluation (PRAISE) trial, we used enzyme-linked immunosorbent assay to measure plasma levels of TNF-alpha in 92 patients and IL-6 in 62 patients in New York Heart Association functional classes III and IV randomized to receive amlodipine (10 mg/day) or placebo. Blood samples were obtained for cytokine measurement at baseline and at 8 and 26 weeks after enrollment. RESULTS: The baseline amlodipine and placebo groups did not differ in demographics and cytokine levels. Mean (+/- SD) plasma levels of TNF-alpha were 5.69 +/- 0.32 pg/ml, and those of IL-6 were 9.23 +/- 1.26 pg/ml at baseline. These levels were elevated 6 and 10 times, respectively, compared with those of normal subjects (p < 0.001). Levels of TNF-alpha did not change significantly over the 26-week period (p = 0.69). However, IL-6 levels were significantly lower at 26 weeks in patients treated with amlodipine versus placebo (p = 0.007 by the Wilcoxon signed-rank test). An adverse event-CHF or death-occurred more commonly in patients with higher IL-6 levels. CONCLUSIONS: Amlodipine lowers plasma IL-6 levels in patients with CHF. The beneficial effect of amlodipine in CHF may be due to a reduction of cytokines such as IL-6.

Carvedilol inhibits clinical progression in patients with mild symptoms of heart failure. US Carvedilol Heart Failure Study Group.

BACKGROUND: We tested the hypothesis that carvedilol inhibits clinical progression in patients with mildly symptomatic heart failure due to left ventricular (LV) systolic dysfunction. METHODS AND RESULTS: Patients (n = 366) who had mildly symptomatic heart failure with an LV ejection fraction (LVEF) < or = 0.35, had minimal functional impairment (defined as the ability to walk 450 to 550 m on a 6-minute walk test), and were receiving optimal standard therapy, including ACE inhibitors, were randomized double-blind to carvedilol (n = 232) or placebo (n = 134) and followed up for 12 months. The primary end point was clinical progression, defined as death due to heart failure, hospitalization for heart failure, or a sustained increase in heart failure medications. Clinical progression of heart failure occurred in 21% of placebo patients and 11% of carvedilol patients, reflecting a 48% (P = .008) reduction in the primary end point of heart failure progression (relative risk, 0.52; CI, 0.32 to 0.85). This effect of carvedilol was not influenced by sex, age, race, cause of heart failure, or baseline LVEF. Carvedilol also significantly improved several secondary end points, including LVEF, heart failure score, NYHA functional class, and the physician and patient global assessments. Carvedilol reduced all-cause mortality but had no effects on the Minnesota Living With Heart Failure scale, the distance walked in 9 minutes on a self-powered treadmill, or cardiothoracic index. The drug was well tolerated. CONCLUSIONS: Carvedilol, when added to standard therapy, including an ACE inhibitor, reduces clinical progression in patients who are only mildly symptomatic with well-compensated heart failure.

The impact of cross-training on team functioning: an empirical investigation.

The effects of cross-training (presence vs. absence) and workload (high vs. low) on team processes, communication, and task performance were examined. Eighty male undergraduate students were randomly assigned to one of four training conditions: cross-training, low workload; cross-training, high workload; no cross-training, low workload; and no cross-training, high workload. Results indicated that cross-training was an important determinant of effective teamwork process, communication, and performance. Predicted interactions between cross-training and workload were not supported. Implications for the design and implementation of cross-training as a means to improve team functioning are discussed.

A cost benefit analysis of outsourced laboratory services.

As healthcare moves toward increased capitation, hospital administrators must be aware of all costs associated with patient services. This article describes the cost benefit analysis process used by northern Indiana hospital consumers during 1994-1995 to evaluate a local laboratory service outsource provider, South Bend Medical Foundation (SBMF). In an effort to meet the best interests of the community at large, three competing hospitals, medical leadership, and the local outsource provider joined forces to ensure that cost effective quality services would be provided. Laboratory utilization patterns for common DRGs were also analyzed. The team created a reconfiguration analysis to help develop benchmark figures for consideration in future contract negotiations.

Percutaneous laser-assisted balloon angioplasty of lower-extremity arterial disease in a free-standing laboratory: clinical experience with 100 cases.

From September 1987 through May 1988, 86 patients (62 men and 24 women) underwent percutaneous laser-assisted balloon angioplasty, and 2 patients (1 man and 1 woman) underwent laser-assisted balloon angioplasty via cutdowns, in our free-standing catheterization laboratory. The patients' ages ranged from 36 to 81 years. One hundred limbs were treated; each had at least 1 total occlusion, and many had multiple significant occlusions (greater than 50%). Vascular access was attained via the common femoral artery in 62 limbs, via the popliteal artery in 34 limbs, and via a posterior tibial artery cutdown in 4 limbs. In all, 232 lesions were treated either by percutaneous laser-assisted balloon angioplasty (172 lesions) or by balloon angioplasty alone (60 lesions). Technical success was defined as "recanalization and dilation of the occluded arterial segment, resulting in a recognizable improvement in pulse that persisted until hospital discharge." The technical success/attempt ratios for the 172 laser-assisted treatments were as follows: iliac artery, 11/17 (64.7%); common femoral artery, 8/9 (88.9%); superficial femoral artery, 62/80 (77.5%); popliteal artery, 25/30 (83.3%); peroneal artery, 14/16 (87.5%); anterior tibial artery, 6/7 (85.7%); and posterior tibial artery, 9/13 (69.2%). Technical failure occurred in 25 limbs. Failure was not related to sex, age, approach artery, or diabetes, but it was related to the indication of impending limb loss (p < 0.01), previous vascular surgery (p < 0.01), amputation (p < 0.01), and lesion length of 20 cm or greater. Clinical success was defined as "clinical improvement in symptoms, with persistence of an improved pulse at follow-up." Recurrence was observed in 10 limbs. Recurrence was not related to sex, age, approach artery, diabetes, or lesion length, but it was related to the indication of impending limb loss (p < 0.05); to the fact that the patient was a cigarette smoker at the time of the procedure (p < 0.02); and (inversely) to the number of tibial vessels that remained patent post-intervention. Five patients required emergency surgery after laser-assisted angioplasty, but no limb amputation has been necessary. Minor complications included perforation (16 cases), hematoma formation (6 cases), dissection (3 cases), hemorrhage (1 case), hives (1 case), and fracture of the laser probe (1 case). We conclude that percutaneous laser-assisted balloon angioplasty can be safely accomplished in a free-standing laboratory and that the procedure is reasonably successful in patients with totally occluded lower-extremity arteries.

Thiamin content of chicken muscle and effect of purification variables on determined values.

Experiments were conducted to investigate 1) effects of selected purification variables [flow rate, temperature, and volume of eluent using two resins, Decalso and Bio-Rex 70 (Bio-Rad Laboratories, Richmond, CA)] on the determined thiamin values of fried chicken and 2) effects of cooking methods on thiamin content of fast food-fried chicken breast muscle using a modified Association of Official Analytical Chemists method. With Decalso, a flow rate of less than 1 mL/min produced satisfactory recovery of thiamin in a standard solution of more than 94%; the use of a faster flow rate of more than 1.5 mL/min resulted in a low recovery value (around 82%). Hot eluent temperature significantly increased thiamin recovery from 90.1 to 99.4%. Thiamin recovery from the Bio-Rex 70 was affected minimally by eluent flow rate, eluent temperature, and eluent volume. A recovery value of about 97% was obtained from the Bio-Rex 70 at all flow rates, with the highest value at 1.5 mL/min. Generally, the use of Bio-Rex 70 resulted in slightly lower determined thiamin values for fried chicken meat but higher and more consistent recovery of a standard thiamin solution than the use of Decalso. The thiamin contents of chicken breast muscles cooked by the two methods were not significantly different (pressure-fried chicken, .207; open vat-fried chicken, .239 mg/100 g on a moisture and fat-free basis).

Vitamin and proximate composition of fast-food fried chicken.

As part of the USDA's effort to obtain accurate data for nutrient composition handbooks, we determined proximate composition and vitamin (thiamin, riboflavin, niacin, folacin, pantothenic acid, and vitamins B-6 and B-12) content of fast-food fried chicken. Ninety-four samples were purchased from six chains in 10 cities throughout the United States. Vitamin content of breast and thigh meat portions differed, and slight differences in composition among brands were noted. Thiamin values for breast and thigh muscle, respectively, ranged from 0.062 to 0.136 and from 0.078 to 0.122 mg/100 gm; riboflavin, from 0.176 to 0.205 and 0.249 to 0.328 mg/100 gm; niacin, from 6.32 to 8.46 and 3.86 to 5.57 mg/100 gm; vitamin B-6, from 0.315 to 0.390 and 0.189 to 0.271 mg/100 gm; folacin, from 4.2 to 6.9 and 5.00 to 8.00 micrograms/100 gm; vitamin B-12, from 0.331 to 0.459 and 0.382 to 0.596 micrograms/100 gm; and pantothenic acid, from 1.48 to 1.68 and 1.58 to 1.77 mg/100 gm. Pressure-fried samples tended to have higher percentage moisture and lower percentage fat than crispy, open-vat fried samples. Fat ranged from about 15% to 20%.

B-vitamin retention in meat during storage and preparation. A review.

In this review, the authors bring together present information on B-vitamin retention in frozen meat as it is affected by: Aging before freezing, the freezing process and length of frozen storage, cooking from the frozen or thawed state, method of thawing, cooking methods, and holding and reheating conditions. Literature reports on various cuts of pork, chicken, beef, lamb, turkey and veal are cited. Thiamin, riboflavin, niacin, vitamin B6, pantothenic acid, vitamin B12, biotin, choline, and folic acid are considered.

Vitamin B 6 in reheated, held, and freshly cooked turkey breast.

Vitamin B6 content, percentage total moisture, and ether extract of freshly roasted turkey breast muscle; muscle reheated in either an electric or microwave oven; and muscle sliced and held after roasting were evaluated. Reheating times were recorded, and losses were calculated. Reheating time was less (p smaller than 0.01) and total reheating loss greater (P smaller than 0.05) for quarters reheated in the microwave oven. Muscle reheated in the microwave oven had greater volatile (P smaller 0;05) but less drip (P smaller than 0.05) loss than did that reheated in the electric oven. Moisture content was greater (P smaller than 0.05) in freshly roasted muscle. When vitamin B6 was calculated on the basis of cooked weight, no significant differences were observed among treatments. However, when calculation was on a moisture-free and fat-free basis, freshly roasted samples contained the most (P smaller than 0.05) vitamin B6. Although we found significant differences due to treatment variation among birds was greater than among treatments.