Distribution of active gene sequences: a subset associated with tightly bound chromosomal proteins.

The distribution of active polyadenylate-messenger RNA sequences in fractionated chicken liver chromatin was examined. A portion of these active gene sequences is concentrated in a DNA fraction retained by tightly bound nonhistone chromosomal proteins, while the nonretained DNA fraction is substantially depleted of a portion of these sequences. These findings suggest that the tightly bound nonhistones are physically associated with a subset of active gene sequences.

Leaf temperatures of desert plants.

Temperatures of small leaves of many desert plants are within 3 degrees C of air temperature in contrast to the temperature of Opuntia in the same locale; this plant has a temperature 10 degrees to 16 degrees C above air temperature. Theoretical4 justification for the observation is given based on an energy budget analysis.

Risk factors for disability among U.S. adults with arthritis.

This article studies risk factors for physical and social disability among U.S. adults ages 55+ who have arthritis, compared to non-arthritis persons of those ages. The dependent variables refer to difficulties in walking, physical functioning (motions and strength), personal care, and household care. The data set is the Supplement on Aging (SOA) (n = 16,148) that accompanied the 1984 National Health Interview Survey. The SOA data are cross-sectional; relationships of risk factors to disability suggest causation but do not directly demonstrate it. Logistic regressions show that risk factors are similar for arthritis and non-arthritis people, with one important exception. (1) The similarities are: For both groups, odds of disability rise with age, diminish with education, and are higher for non-whites and non-married persons. Disability rises with number of chronic diseases and impairments, and it is elevated for underweight persons (Body Mass Index (BMI) less than 20; further analysis indicates this reflects incomplete control of their severe illness status). Long duration of arthritis and recent medical care for it are associated with disability. (2) The exception is: Severe overweight (BMI greater than or equal to 30) is a disability risk factor for arthritis people, but not for non-arthritis people. Previous research has shown that obesity/overweight is a risk factor for etiology of osteoarthritis; our analysis now shows its continued importance for disability when the disease is present.

Development of a photosynthesis model with an emphasis on ecological applications : V. Test of the applicability of a steady-state model to description of net photosynthesis of Prunus armeniaca under field conditions.

A physiologically based steady-state model of whole leaf photosynthesis (WHOLEPHOT) is used to describe net photosynthesis daily time courses in Prunus armeniaca. Net photosynthesis rates are calculated in response to incident light intensity, leaf temperature, air carbon dioxide concentration, and leaf diffusion resistance measured at five minute intervals. The steady-state calculations closely approximate the observed net photosynthesis rates for a broad range of weather conditions and leaf stomatal behavior.

Development of a photosynthesis model with an emphasis on ecological applications : I. Theory.

In this paper, a description of photosynthesis in a single leaf is developed that separates physiological sub-processes and that is practical to apply as an ecological tool. Temperature dependencies are emphasized with the ultimate aim of linking such a description of photosynthesis with equations describing the energy budget of particular leaves. The description of photosynthesis can be applied toC 4 plants at this time and is needed to describe photosynthesis inC 3 plants when photorespiration is included. If the model is used to analyze at various times the response of a plant adjusting its metabolism to changes in light, temperature, or other factors experienced during growth, we will obtain a dynamic picture of the acclimation process. It will also be possible to determine the phenotypic plasticity of particular plants with respect to the metabolic sub-processes outlined.

The diurnal time course of net photosynthesis of soybean leaves: Analysis with a physiologically based steady-state photosynthesis model.

A physiologically based steady-state model of whole leaf photosynthesis (WHOLEPHOT) is used to analyze observed net photosynthesis daily time courses of soybean, Glycine max (L.) Merr., leaves. Observations during two time periods of the 1978 growing season are analyzed and compared. After adjustment of the model for soybean, net photosynthesis rates are calculated with the model in response to measured incident light intensity, leaf temperature, air carbon dioxide concentration, and leaf diffusion resistance. The steady-state calculations closely approximate observed net photosynthesis. Results of the comparison reveal a decrease in photosynthetic capacity in leaves sampled during the second time period, which is associated with decreasing ability of leaves to respond to light intensity and internal air space carbon dioxide concentration, increasing mesophyll resistance, and increasing stomatal resistance.

Analysis of gas exchange in seedlings of Acer saccharum: integration of field and laboratory studies.

In the field, photosynthesis of Acer saccharum seedlings was rarely light saturated, even though light saturation occurs at about 100 µmol quanta m-2 s-1 photosynthetic photon flux density (PPFD). PPFD during more than 75% of the daylight period was 50 µmol m-2 s-1 or less. At these low PPFD's there is a marked interaction of PPFD with the initial slope (CE) of the CO2 response. At PPFD-saturation CE was 0.018 µmol m-2 s-1/(µl/l). The apparent quantum efficiency (incident PPFD) at saturating CO2 was 0.05-0.08 mol/mol. [Formula: see text] and PPFD-saturated CO2 exchange was 6-8 µmol m-2 s-1. The ratio of internal CO2 concentration to external (C i /C a ) was 0.7 to 0.8 except during sunflecks when it decreased to 0.5. The decrease in C i /C a during sunflecks was the result of the slow response of stomates to increased PPFD compared to the response of net photosynthesis. An empirical model, which included the above parameters was used to simulate the measured CO2 exchange rate for portions of two days. Parameter values for the model were determined in experiments separate from the daily time courses being sumulated. Analysis of the field data, partly through the use of simulations, indicate that the elimination of sunflecks would reduce net carbon gain by 5-10%.

Development of a photosynthesis model with an emphasis on ecological applications : III. Carbon dioxide and oxygen dependencies.

A theoretical description of the simultaneous processes of photosynthesis and photorespiration in a single leaf is developed, based on the hypothesis that carbon dioxide and oxygen compete for the active site of ribulose diphosphate carboxylase. Michaelis-Menten kinetics and competitive inhibition at the end of a diffusion path provide the basic structure of the model. Data of Ludwig (1972) from sunflower are analyzed according to the formulation. This description is part of a more general physiological-ecological model of photosynthesis presented previously (Tenhunen et al., 1976a, b) and continues to elaborate sub-processes in terms of physiologically meaningful parameters. The description is considered a working hypothesis. Data on photorespiration from the literature are reviewed as they relate to this working hypothesis. Several lines of investigation are thereby suggested that will help clarify the role of photorespiration in whole leaf photosynthesis and determine the over-all utility of this modeling approach.

Development of a photosynthesis model with an emphasis on ecological applications : II. Analysis of a data set describing theP M surface.

Photosynthesis was measured in leaves ofPhaseolus vulgaris and analyzed according to the set of equations outlined previously by Tenhunen et al. (1976).

Outsourcing the preparation of parenteral nutrient solutions.

A hospital pharmacy's experience with using an outsourcing center to prepare parenteral nutrient solutions (PNs) is described. In 1994 the pharmacy at a 340-bed level 1 trauma center selected an outsourcing center located 20 miles away to provide PN-compounding services; the center is licensed as a manufacturer and has an extensive quality control program. The necessary telephone and computer links were established. When a PN order is received, the pharmacist simply dials into the outsourcing computer system and enters the order. At 1400, a pharmacist dials into the system to verify all PN orders entered for that day. After 1500, personnel at the outsourcing center print labels and compound the solutions, which are delivered by courier within a few hours. The net savings during the first year of outsourcing PNs were estimated at about $59,000. The savings were attributable to the elimination of a technician full-time equivalent (FTE), a reduction in pharmacist labor, and favorable contract provisions; money was saved even though the service's PN-preparation fees outweighed the savings from reductions in labor. The hospital's onsite inventory of PN supplies decreased by $5800, and storage space was freed for other uses. Very few problems were associated with the service provided. Outsourcing the preparation of parenteral nutrient solutions reduced personnel, inventory, and expenditures in a hospital pharmacy.

Using simulations and standardized patients in intervention research.

Caregiving is both an art and a science; both knowledge and skills are necessary to improve the quality of care that professionals provide. Researchers are often limited in their assessment of skill performance due to inadequate and unrealistic measurement options. Simulation using standardized patients offers researchers an objective method to evaluate skill performance. This article describes the use of simulations by researchers in their quest to measure changes in violence prevention skills after an intervention program given to nurse assistants working in long-term care facilities.

Violence against caregivers in nursing homes. Expected, tolerated, and accepted.

Violence against caregivers is not a new phenomenon. Caregivers have experienced verbal and physical assaults from nursing home residents for many years. However, because much of the violence has been associated with demented or mentally ill residents, the word aggression was used in lieu of violence. This study found that the caregivers and nursing directors considered the assaults to be violence. The study suggests that such violence occurs frequently and is of concern to caregivers and nursing directors. The study also suggests that nursing homes may not have policies or procedures in place for preventing, monitoring, and controlling violence in their workplaces. In 1996, OSHA published violence prevention guidelines for health are facilities. These guidelines support OSHA's mandate that employees are entitled to a safe and healthy workplace (OSHA, 1996b). Although it is not possible to prevent all violence against caregivers in this unique setting, nursing home directors and administrators have a legal and moral responsibility to develop an action plan to minimize the violence and plan interventions for its effects. Violence against caregivers in nursing homes no longer can be thought of as expected, tolerated, and accepted. Quality of care and employee well-being depend on it.

Workplace violence.

Research related to workplace violence is in its infancy. The epidemiologic data, which are just beginning to appear in the literature, show that workplace violence is a growing concern for employers and employees. Experts provide suggestions on ways to prevent workplace violence, but the literature lacks studies that examine the use or results of such activities. Included in these suggestions is the need to implement violence prevention policies and procedures, security controls, screening, employee assistance programs, and workplace education/training for employees and managers. Occupational health nurses are in a unique position to provide violence prevention programs in the workplace.

Stress and coping. A model for the workplace.

Stress, both positive and negative, is a part of personal and work life. Some stressors in the work environment are so extreme they cause strain to all employees. Such conditions require immediate response by employers to change the work environment. However, understanding most workplace stress requires an approach examining the fit between the individual and the work. Only by holistically examining the relationships between the worker's characteristics and the job's characteristics can successful intervention strategies be planned and implemented. Once occupational and environmental health nurses have completed an occupational stress assessment they can plan primary, secondary, and tertiary interventions to meet the specific needs of the employees and the organization.

Workplace violence: occupational health nurses' beliefs and experiences.

The purpose of this descriptive study was to describe occupational health nurses' beliefs about workplace violence and violence prevention education. The study examined what nurses believe about their intentions and ability to provide violence prevention education, as well as barriers they perceive to providing such programs. A survey was sent to a random sample of 700 members of the AAOHN; 357 surveys were used for data analysis. The study found that many occupational health nurses believe they and their companies are at risk for violence. In addition, many of the occupational health nurses had experienced harassment, threats, or assaults at their workplaces during the previous 12 months. Few occupational health nurses had provided violence prevention programs in their workplaces or intended to provide such programs during the following 12 months. The largest barrier to providing violence prevention education was the employer did not recognize violence prevention education as part of the nurse's job responsibilities.

Promoting maternal-child wellness in the workplace.

With increased numbers of women in the workplace, corporations are recognizing the need for maternal-child wellness programming. Prenatal risk assessment and screenings with follow up educational programs can reduce infant mortality and morbidity, thereby reducing dollars spent by industry for health care of women and children. Occupational health nurses can serve as change agents in implementing prenatal, postnatal, and family oriented wellness programs in the workplace.