Control of high-speed jumps: the rotation and energetics of the locust (Schistocerca gregaria).

Locusts (Schistocerca gregaria) jump using a latch mediated spring actuated system in the femur-tibia joint of their metathoracic legs. These jumps are exceptionally fast and display angular rotation immediately after take-off. In this study, we focus on the angular velocity, at take-off, of locusts ranging between 0.049 and 1.50 g to determine if and how rotation-rate scales with size. From 263 jumps recorded from 44 individuals, we found that angular velocity scales with mass-0.33, consistent with a hypothesis of locusts having a constant rotational kinetic energy density. Within the data from each locust, angular velocity increased proportionally with linear velocity, suggesting the two cannot be independently controlled and thus a fixed energy budget is formed at take-off. On average, the energy budget of a jump is distributed 98.7% to translational kinetic energy and gravitational potential energy, and 1.3% to rotational kinetic energy. The percentage of energy devoted to rotation was constant across all sizes of locusts and represents a very small proportion of the energy budget. This analysis suggests that smaller locusts find it harder to jump without body rotation.

Effect of calcium on moving-bed biofilm reactor biofilms.

The effect of calcium concentration on the biofilm structure, microbiology, and treatment performance was evaluated in a moving-bed biofilm reactor. Three experiments were conducted in replicate laboratory-scale reactors to determine if wastewater calcium is an important variable for the design and optimization of these reactors. Biofilm structural properties, such as thickness, oxygen microprofiles, and the composition of extracellular polymeric substances (EPS) were affected by increasing calcium concentrations. Above a threshold concentration of calcium between 1 and 50 mg/L, biofilms became thicker and denser, with a shift toward increasingly proteinaceous EPS at higher calcium concentrations up to 200 mgCa2+/L. At 300 mgCa2+/L, biofilms were found to become primarily composed of inorganic calcium precipitates. Microbiology was assessed through microscopy, denaturing grade gel electrophoresis, and enumeration of higher organisms. Higher calcium concentrations were found to change the bacterial community and promote the abundant growth of filamentous organisms and various protazoa and metazoan populations. The chemical oxygen demand removal efficiency was improved for reactors at calcium concentrations of 50 mg/L and above. Reactor effluents for the lowest calcium concentration (1 mgCa2+/L) were found to be turbid (>50 NTU), as a result of the detachment of small and poorly settling planktonic biomass, whereas higher concentrations promoted settling of the suspended phase. In general, calcium was found to be an important variable causing significant changes in biofilm structure and reactor function.

The clinical needs of patients with chronic gastrointestinal symptoms after pelvic radiotherapy.

BACKGROUND: After radiotherapy for pelvic cancer, gastrointestinal symptoms affecting quality of life are common. How they affect daily living is unknown. AIM: To investigate the day-to-day impact of gastrointestinal symptoms in patients after pelvic radiotherapy. METHODS: New patients referred for gastroenterological evaluation of radiotherapy-induced symptoms were sent a questionnaire. RESULTS: Over 15 months, 75 of 100 questionnaires were completed before the gastroenterology appointment by 45 men (median age 70) and 30 women (median age 57) treated for urological (n = 44), gynaecological (n = 27) and gastrointestinal (n = 4) cancers. Time since radiotherapy was 3 years (median) for women and 1.5 years (men). Women experienced 6 (median) symptoms whilst men experienced 4. Having someone listen to problems was often as important as treatment. Urgency, diarrhoea, pain, rectal bleeding, flatulence and bloating were particularly troublesome. 57% women and 33% men were 'very affected'. Symptoms rarely improved with time and in 33% had been present for more than 2 years. Gastrointestinal symptoms affected quality of life through change of routine (F 37%, M 22%), social limitation (F 17%, M 33%), physical limitations (F 33%, M 16%), emotional difficulties (F 47%, M 18%) and sexual problems (F 30%, M 51%). CONCLUSIONS: Patients experience a high number of physical symptoms for long periods before referral. Clinicians must focus systematically on physical, emotional and psychosexual issues.

Multivariate statistical analysis of a high rate biofilm process treating kraft mill bleach plant effluent.

This study reports on a multivariate analysis of the moving bed biofilm reactor (MBBR) wastewater treatment system at a Canadian pulp mill. The modelling approach involved a data overview by principal component analysis (PCA) followed by partial least squares (PLS) modelling with the objective of explaining and predicting changes in the BOD output of the reactor. Over two years of data with 87 process measurements were used to build the models. Variables were collected from the MBBR control scheme as well as upstream in the bleach plant and in digestion. To account for process dynamics, a variable lagging approach was used for variables with significant temporal correlations. It was found that wood type pulped at the mill was a significant variable governing reactor performance. Other important variables included flow parameters, faults in the temperature or pH control of the reactor, and some potential indirect indicators of biomass activity (residual nitrogen and pH out). The most predictive model was found to have an RMSEP value of 606 kgBOD/d, representing a 14.5% average error. This was a good fit, given the measurement error of the BOD test. Overall, the statistical approach was effective in describing and predicting MBBR treatment performance.

Visual influences on the development and recovery of the vestibuloocular reflex in the chicken.

Whenever the head turns, the vestibuloocular reflex (VOR) produces compensatory eye movements to help stabilize the image of the visual world on the retina. Uncompensated slip of the visual world across the retina results in a gradual change in VOR gain to minimize the image motion. VOR gain changes naturally during normal development and during recovery from neuronal damage. We ask here whether visual slip is necessary for the development of the chicken VOR (as in other species) and whether it is required for the recovery of the VOR after hair cell loss and regeneration. In the first experiment, chickens were reared under stroboscopic illumination, which eliminated visual slip. The horizontal and vertical VORs (h- and vVORs) were measured at different ages and compared with those of chickens reared in normal light. Strobe-rearing prevented the normal development of both h- and vVORs. After 8 wk of strobe-rearing, 3 days of exposure to normal light caused the VORs to recover partially but not to normal values. In the second experiment, 1-wk-old chicks were treated with streptomycin, which destroys most vestibular hair cells and reduces hVOR gain to zero. In birds, vestibular hair cells regenerate so that after 8 wk in normal illumination they appear normal and hVOR gain returns to values that are normal for birds of that age. The treated birds in this study recovered in either normal or stroboscopic illumination. Their hVOR and vVOR and vestibulocollic reflexes (VCR) were measured and compared with those of untreated, age-matched controls at 8 wk posthatch, when hair cell regeneration is known to be complete. As in previous studies, the gain of the VOR decreased immediately to zero after streptomycin treatment. After 8 wk of recovery under normal light, the hVOR was normal, but vVOR gain was less than normal. After 8 wk of recovery under stroboscopic illumination, hVOR gain was less than normal at all frequencies. VCR recovery was not affected by the strobe environment. When streptomycin-treated, strobe-recovered birds were then placed in normal light for 2 days, hVOR gain returned to normal. Taken together, the results of these experiments suggest that continuous visual feedback can adjust VOR gain. In the absence of appropriate visual stimuli, however, there is a default VOR gain and phase to which birds recover or revert, regardless of age. Thus an 8-wk-old chicken raised in a strobe environment from hatch would have the same gain as a streptomycin-treated chicken that recovers in a strobe environment.

Nurse experience and education: effect on quality of care.

OBJECTIVE: To describe the relationships between the quality of patient care and the education and experience of the nurses providing that care. BACKGROUND: There is a call for more nurses with baccalaureate degrees and more experienced nurses to work in hospitals. Previous research studies have examined the characteristics, abilities, and work assignments of nurses with and without baccalaureate degrees but have not examined the quality of the patient care delivered. It is generally believed that more experienced nurses provide higher-quality care, but again few studies have actually examined this issue. METHODS: A secondary analysis of data, collected in two previous studies of the relationship between nurse staffing (hours of care, staff mix) and the quality of patient care, was used to determine the relationship between nurses' education and experience and the quality of care provided. The data were collected at the patient care unit level (42 units in study 1 and 39 units in study 2). Quality of care was indicated by lower unit rates of medication errors and patient falls. RESULTS: Controlling for patient acuity, hours of nursing care, and staff mix, units with more experienced nurses had lower medication errors and lower patient fall rates. These adverse occurrence rates on units with more baccalaureate-prepared nurses were not significantly better.

The Iowa Model of Evidence-Based Practice to Promote Quality Care.

The UIHC Department of Nursing is nationally known for its work on use of research to improve patient care. This reputation is attributable to staff members who continue to question "how can we improve practice?" or "what does the latest evidence tell us about this patient problem?" and to administrators who support, value, and reward EBP. The revisions made in the original Iowa Model are based on suggestions from staff at UIHC and other practitioners across the country who have implemented the model. We value their feedback and have set forth this revised model for evaluation and adoption by others.

Outcomes from use of an evidence-based practice guideline.

The aim of evidence-based guidelines is primarily to improve patient outcomes without adding to the existing cost of care because both payers and policymakers want to identify health care costs that do not result in benefit to the patient. The purpose of the reported project was to generate a practice guideline for the treatment of uncomplicated acute cystitis in a female population, to determine the extent to which the guideline would be used by providers and to measure the cost and quality of outcomes from its use. A retrospective chart review was used to gather pre-guideline practice and cost data. Measurements included the type, frequency, and duration of antibiotic therapy and the use of urine cultures and both complications and routine followup visits. The implementation of an outpatient practice guideline resulted in a significant change in antibiotic prescribing and a trend toward a change in ordering cultures and clinic followup. There was also a significant decrease in treatment costs.

A clinical advancement program: evaluating 10 years of progressive change.

OBJECTIVE: To report the evolution of a clinical advancement program, UEXCEL, at a western teaching hospital and the outcomes associated with evaluation over time. BACKGROUND: The clinical ladder program was initiated in 1989 to provide a professional framework for developing, evaluating, and promoting registered nurses. The program is derived from Benner's Novice to Expert model. Over a 10-year period, the program has undergone three significant revisions. Program evaluation data have been used to guide institutional change. METHODS: Structure and progression of program development and change are outlined. Evaluation data were collected using a 23-item clinical ladder satisfaction scale developed by Strzelecki. Data were collected in 1993, 1994, 1996, and 1998 using standard survey methods after institutional review board approval. Subjects were registered nurses holding clinical positions at the University of Colorado Hospital. Data were trended across units and time periods and were compared with other institutional evaluation data sets. RESULTS: Improvement in nurse satisfaction with the UEXCEL program has been steady and incremental, after low baseline measurement. Satisfaction has improved after each program revision. A significant demographic variable over time is the correlation between higher registered nurse education and program satisfaction. Human resources issues are reported with data results. CONCLUSIONS: Sustaining a clinical advancement program represents a challenge in the current health-care environment. Institutional commitment, staff involvement in revisions, and activities to improve professional nurse development are critical strategies so progress can be achieved.

Evaluating nursing administration instruments.

OBJECTIVE: To identify and evaluate available measures that can be used to examine the effects of management innovations in five important areas: autonomy, conflict, job satisfaction, leadership, and organizational climate. BACKGROUND: Management interventions target the context in which care is delivered and through which evidence for practice diffuses. These innovations need to be evaluated for their effects on desired outcomes. However, busy nurses may not have the time to locate, evaluate, and select instruments to measure expected nursing administration outcomes without research-based guidance. Multiple and complex important contextual variables need psychometrically sound and easy-to-use measurement instruments identified for use in both practice and research. METHOD: An expert focus group consensus methodology was used in this evaluation research to review available instruments in the five areas and evaluate which of these instruments are psychometrically sound and easy to use in the practice setting. RESULTS: The result is a portfolio of measures, clustered by concept and displayed on a spreadsheet. Retrieval information is provided. The portfolio includes the expert consensus judgment as well as useful descriptive information. CONCLUSIONS: The research reported here identifies psychometrically sound and easy-to-use instruments for measuring five key variables to be included in a portfolio. The results of this study can be used as a beginning for saving time in instrument selection and as an aid for determining the best instrument for measuring outcomes from a clinical or management intervention.

Activation of follicle cell surface phospholipase by tyrosine kinase dependent pathway is an essential event in Ascidian fertilization.

Eggs of Ascidia ceratodes and Phallusia mammillata block polyspermy by releasing a phosphatidylinositol-linked glycosidase from the follicle cell and egg surface that binds to and blocks all unoccupied sperm binding sites on the vitelline coat. Release of this glycosidase is thought to be under the control of a membrane-bound phospholipase. To elucidate the mechanism of phospholipase activation, intact eggs and isolated follicle cells are activated by either sperm or the tyrosine kinase activator 9, 10-dimethyl-1,2-benzanthracene (DMBA). Both treatments caused release of comparable quantities of glycosidase activity, the earliest event following fertilization. A corresponding increase in phospholipase activity accompanied this glycosidase release. The tyrosine kinase inhibitor genistein blocked release by DMBA at concentrations as low as 1 microM, but had no effect on sperm-induced release even when used up to 100 microM. Tyrphostin A23, another tyrosine kinase inhibitor, when used at 200 microM blocked glycosidase release and decreased phospholipase activity following both DMBA activation and fertilization. Western blot analysis probing for phosphotyrosine content of disrupted intact eggs with their follicle cells revealed the absence of a band in tyrphostin-treated eggs corresponding to a 40 kDa protein that was present in both unfertilized and fertilized egg samples. Based on these results, we propose that phosphorylation of specific tyrosine residues is necessary for phospholipase activation and is sufficient to trigger subsequent glycosidase release.

Evidence-based clinical practice.

Healthcare professionals are trying to facilitate the use of evidence-based decision making for individual patients and patient populations they are privileged to serve. The authors describe an evidence-based multidisciplinary clinical practice model developed at the University of Colorado Hospital along with a clinical example of how the model was used to improve quality and decrease costs.

Recovery of the vestibulocolic reflex after aminoglycoside ototoxicity in domestic chickens.

Avian auditory and vestibular hair cells regenerate after damage by ototoxic drugs, but until recently there was little evidence that regenerated vestibular hair cells function normally. In an earlier study we showed that the vestibuloocular reflex (VOR) is eliminated with aminoglycoside antibiotic treatment and recovers as hair cells regenerate. The VOR, which stabilizes the eye in the head, is an open-loop system that is thought to depend largely on regularly firing afferents. Recovery of the VOR is highly correlated with the regeneration of type I hair cells. In contrast, the vestibulocolic reflex (VCR), which stabilizes the head in space, is a closed-loop, negative-feedback system that seems to depend more on irregularly firing afferent input and is thought to be subserved by different circuitry than the VOR. We examined whether this different reflex also of vestibular origin would show similar recovery after hair cell regeneration. Lesions of the vestibular hair cells of 10-day-old chicks were created by a 5-day course of streptomycin sulfate. One day after completion of streptomycin treatment there was no measurable VCR gain, and total hair cell density was approximately 35% of that in untreated, age-matched controls. At 2 wk postlesion there was significant recovery of the VCR; at this time two subjects showed VCR gains within the range of control chicks. At 3 wk postlesion all subjects showed VCR gains and phase shifts within the normal range. These data show that the VCR recovers before the VOR. Unlike VOR gain, recovering VCR gain correlates equally well with the density of regenerating type I and type II vestibular hair cells, except at high frequencies. Several factors other than hair cell regeneration, such as length of stereocilia, reafferentation of hair cells, and compensation involving central neural pathways, may be involved in behavioral recovery. Our data suggest that one or more of these factors differentially affect the recovery of these two vestibular reflexes.

Adverse patient occurrences as a measure of nursing care quality.

OBJECTIVE: The purpose of this study was to describe relationships among adverse patient occurrences aggregated at the unit level of measurement. Relationships between adverse occurrences and a patient acuity measure were also described. BACKGROUND: Adverse patient occurrence data have been traditionally a major indicator of quality care in hospitals; however, few studies have examined relationships among these indicators or the usefulness of these indicators for assessing the quality of nursing care. METHODS: A correlational design was used to examine and describe patterns of relationships among in-patient units in a tertiary care hospital. The results demonstrated positive correlations between medication error rates and patient falls; these adverse occurrences correlated negatively with pressure ulcers, infections, patient complaints, and death. Pressure ulcers, infections, patient complaints and death intercorrelated positively and also related positively to patient acuity levels. RESULTS: An examination of these same rates for a subset of units with similar patient acuity levels revealed that most of the interrelationships among the entire set of adverse occurrence indicators were positive. When patient acuity was taken into account, these adverse outcomes appeared to indicate some common underlying characteristic of the units, such as quality of nursing care. CONCLUSIONS: This study suggests a relationship between the adverse occurrences that were correlated (pressure ulcers, patient complaints, infection, and death) and the severity of patient illness. Medication error rates and patient fall rates were not correlated with patient acuity and are more likely to indicate quality of nursing care across all types of units.

Nurse staffing and patient outcomes.

BACKGROUND: Nursing studies have shown that nursing care delivery changes affect staff and organizational outcomes, but the effects on client outcomes have not been studied sufficiently. OBJECTIVE: To describe, at the level of the nursing care unit, the relationships among total hours of nursing care, registered nurse (RN) skill mix, and adverse patient outcomes. METHODS: The adverse outcomes included unit rates of medication errors, patient falls, skin breakdown, patient and family complaints, infections, and deaths. The correlations among staffing variables and outcome variables were determined, and multivariate analyses, controlling for patient acuity, were completed. RESULTS: Units with higher average patient acuity had lower rates of medication errors and patient falls but higher rates of the other adverse outcomes. With average patient acuity on the unit controlled, the proportion of hours of care delivered by RNs was inversely related to the unit rates of medication errors, decubiti, and patient complaints. Total hours of care from all nursing personnel were associated directly with the rates of decubiti, complaints, and mortality. An unexpected finding was that the relationship between RN proportion of care was curvilinear; as the RN proportion increased, rates of adverse outcomes decreased up to 87.5%. Above that level, as RN proportion increased, the adverse outcome rates also increased. CONCLUSIONS: The higher the RN skill mix, the lower the incidence of adverse occurrences on inpatient care units.

Evidence for cell surface and internal phospholipase activity in ascidian eggs.

Upon fertilization, ascidian eggs release a cell surface glycosidase used in the block to polyspermy and undergo cortical contractions resulting from increased intracellular calcium levels. The glycosidase is released by fertilization, calcium ionophores or added phospholipase C (PLC) activity. The PLC inhibitor D609 blocks glycosidase release. Intact Ascidia ceratodes eggs cleave 4-methylumbelliferyl-phospho-choline when it is added to seawater. This yields highly fluorescent 4-methylumbelliferone. Authentic phospholipase C but not phospholipase D can cleave this substrate. Thus, the authors believe that cleavage of the substrate is specific for PLC activity. Eggs incubated in the fluorogenic substrate after having been washed and detergent extracted were not fluorescent. Therefore the substrate failed to enter intact cells. Glycosidase release and PLC activity were stimulated by ionomycin. Octylglucoside or Triton X-100 extracts of ascidian eggs had two forms of phospholipase activity as shown by ion affinity chromatography: PL1 eluting at 0.25 mol/L NaCl and PL2 eluting at 0.6 mol/L NaCl. The PL1 appeared to be isolated as a single protein. When surface proteins were labeled with non-penetrating biotin and were subsequently reacted with streptavidin, half of the PLC activity bound. This demonstrates that half the ascidian egg PLC activity is located on the surface of either the egg or follicle cell, and half is located within the egg.