Integrating diverse forage sources reduces feed gaps on mixed crop-livestock farms.

Highly variable climates induce large variability in the supply of forage for livestock and so farmers must manage their livestock systems to reduce the risk of feed gaps (i.e. periods when livestock feed demand exceeds forage supply). However, mixed crop-livestock farmers can utilise a range of feed sources on their farms to help mitigate these risks. This paper reports on the development and application of a simple whole-farm feed-energy balance calculator which is used to evaluate the frequency and magnitude of feed gaps. The calculator matches long-term simulations of variation in forage and metabolisable energy supply from diverse sources against energy demand for different livestock enterprises. Scenarios of increasing the diversity of forage sources in livestock systems is investigated for six locations selected to span Australia's crop-livestock zone. We found that systems relying on only one feed source were prone to higher risk of feed gaps, and hence, would often have to reduce stocking rates to mitigate these risks or use supplementary feed. At all sites, by adding more feed sources to the farm feedbase the continuity of supply of both fresh and carry-over forage was improved, reducing the frequency and magnitude of feed deficits. However, there were diminishing returns from making the feedbase more complex, with combinations of two to three feed sources typically achieving the maximum benefits in terms of reducing the risk of feed gaps. Higher stocking rates could be maintained while limiting risk when combinations of other feed sources were introduced into the feedbase. For the same level of risk, a feedbase relying on a diversity of forage sources could support stocking rates 1.4 to 3 times higher than if they were using a single pasture source. This suggests that there is significant capacity to mitigate both risk of feed gaps at the same time as increasing 'safe' stocking rates through better integration of feed sources on mixed crop-livestock farms across diverse regions and climates.

Decreases in maximal oxygen uptake following long-duration spaceflight: Role of convective and diffusive O2 transport mechanisms.

We have previously predicted that the decrease in maximal oxygen uptake (V̇o2max) that accompanies time in microgravity reflects decrements in both convective and diffusive O2 transport to the mitochondria of the contracting myocytes. The aim of this investigation was therefore to quantify the relative changes in convective O2 transport (Q̇o2) and O2 diffusing capacity (Do2) following long-duration spaceflight. In nine astronauts, resting hemoglobin concentration ([Hb]), V̇o2max, maximal cardiac output (Q̇Tmax), and differences in arterial and venous O2 contents ([Formula: see text]-[Formula: see text]) were obtained retrospectively for International Space Station Increments 19-33 (April 2009-November 2012). Q̇o2 and Do2 were calculated from these variables via integration of Fick's Principle of Mass Conservation and Fick's Law of Diffusion. V̇o2max significantly decreased from pre- to postflight (-53.9 ± 45.5%, P = 0.008). The significant decrease in Q̇Tmax (-7.8 ± 9.1%, P = 0.05), despite an unchanged [Hb], resulted in a significantly decreased Q̇o2 (-11.4 ± 10.5%, P = 0.02). Do2 significantly decreased from pre- to postflight by -27.5 ± 24.5% (P = 0.04), as did the peak [Formula: see text]-[Formula: see text] (-9.2 ± 7.5%, P = 0.007). With the use of linear regression analysis, changes in V̇o2max were significantly correlated with changes in Do2 (R2 = 0.47; P = 0.04). These data suggest that spaceflight decreases both convective and diffusive O2 transport. These results have practical implications for future long-duration space missions and highlight the need to resolve the specific mechanisms underlying these spaceflight-induced changes along the O2 transport pathway.NEW & NOTEWORTHY Long-duration spaceflight elicited a significant decrease in maximal oxygen uptake. Given the adverse physiological adaptations to microgravity along the O2 transport pathway that have been reported, an integrative approach to the determinants of postflight maximal oxygen uptake is needed. We demonstrate that both convective and diffusive oxygen transport are decreased following ~6 mo International Space Station missions.

V̇O2 and HR kinetics before and after International Space Station missions.

PURPOSE: Heart rate (HR), pulmonary and muscle oxygen uptake ([Formula: see text]O2pulm, [Formula: see text]O2musc) kinetics after changes of work rate (WR) indicate regulatory characteristics related to aerobic metabolism. We analysed whether the kinetics of HR, [Formula: see text]O2pulm and [Formula: see text]O2musc are slowed after missions to the International Space Station (ISS). The changes of the kinetics were correlated with [Formula: see text]O2peak data. METHODS: 10 astronauts [4 females, 6 males, age: 48.0 ± 3.8 years, height: 176 ± 7 cm, mass: 74.5 ± 15.9 kg (mean ± SD)] performed an incremental test to determine [Formula: see text]O2peak (before missions on L-110 days, after return on R+1/+10/+36 days), and a cardio-respiratory kinetics test (CRKT) with randomized 30-80 W WR changes to determine HR, [Formula: see text]O2pulm and [Formula: see text]O2musc kinetics by time-series analysis (L-236/-73, R+6/+21). Kinetics were summarized by maximum and related lag of cross-correlation function (CCFmax, CCFlag) of WR with the analysed parameter. RESULTS: Statistically, significant changes were also found for CCFmax([Formula: see text]O2musc) between L-236 and R+6 (P = 0.010), L-236 and R+21 (P = 0.030), L-72 and R+6 (P = 0.043). Between pre-to-post mission change in [Formula: see text]O2peak and CCFmax(HR), a correlation was shown (r SP = 0.67, P = 0.017). CONCLUSION: The [Formula: see text]O2musc kinetics changes indicate aerobic detraining effects which are present up to 21 days following space flight. The correlations between changes in [Formula: see text]O2peak and HR kinetics illustrate the key role of cardiovascular regulation in [Formula: see text]O2peak. The addition of CRKT to ISS flight is recommended to obtain information regarding the potential muscular and cardiovascular deconditioning. This allows a reduction in the frequency of higher intensity testing during flight.

Dr. Zompo: an online data repository for Zostera marina and Posidonia oceanica ESTs.

As ecosystem engineers, seagrasses are angiosperms of paramount ecological importance in shallow shoreline habitats around the globe. Furthermore, the ancestors of independent seagrass lineages have secondarily returned into the sea in separate, independent evolutionary events. Thus, understanding the molecular adaptation of this clade not only makes significant contributions to the field of ecology, but also to principles of parallel evolution as well. With the use of Dr. Zompo, the first interactive seagrass sequence database presented here, new insights into the molecular adaptation of marine environments can be inferred. The database is based on a total of 14 597 ESTs obtained from two seagrass species, Zostera marina and Posidonia oceanica, which have been processed, assembled and comprehensively annotated. Dr. Zompo provides experimentalists with a broad foundation to build experiments and consider challenges associated with the investigation of this class of non-domesticated monocotyledon systems. Our database, based on the Ruby on Rails framework, is rich in features including the retrieval of experimentally determined heat-responsive transcripts, mining for molecular markers (SSRs and SNPs), and weighted key word searches that allow access to annotation gathered on several levels including Pfam domains, GeneOntology and KEGG pathways. Well established plant genome sites such as The Arabidopsis Information Resource (TAIR) and the Rice Genome Annotation Project are interfaced by Dr. Zompo. With this project, we have initialized a valuable resource for plant biologists in general and the seagrass community in particular. The database is expected to grow together with more data to come in the near future, particularly with the recent initiation of the Zostera genome sequencing project.The Dr. Zompo database is available at http://drzompo.uni-muenster.de/

First Report of Soybean Rust Caused by Phakopsora pachyrhizi in North Carolina.

Asian soybean rust, caused by Phakopsora pachyrhizi Sydow, has been known to occur in the eastern hemisphere for nearly a century. More recently, it was reported from South America in 2002 and the continental United States in Louisiana in November 2004 (1,2). Subsequently, P. pachyrhizi was confirmed in Alabama, Arkansas, Georgia, Florida, Missouri, Mississippi, South Carolina, and Tennessee in 2004. Surveys conducted in North Carolina in late November 2004 failed to detect this pathogen. Symptoms of the disease were first observed on soybean (Glycine max (L.) Merr.) in North Carolina on 25 October 2005 in farmers' fields in the counties of Brunswick, Columbus, and Robeson. Typical pustules and urediniospores were readily apparent on infected leaves when viewed with a dissecting microscope. Urediniospores were obovoid to broadly ellipsoidal, hyaline to pale yellowish brown with a minutely echinulate thin wall, and measured 18 to 37 × 15 to 24 µm. This morphology is typical of soybean rust caused by P. pachyrhizi or P. meibomiae, the latter is a less aggressive species causing soybean rust in the western hemisphere (1). DNA was extracted from leaves containing sori using the Qiagen DNeasy Plant Mini kit (Valencia, CA). P. pachyrhizi was detected using a real-time polymerase chain reaction (PCR) protocol that differentiates between P. pachyrhizi and P. meibomiae in a Cepheid thermocycler (Sunnyvale, CA) with appropriate positive and negative controls. The PCR master mix was modified to include OmniMix beads (Cepheid). Field diagnosis of P. pachyrhizi was confirmed by the USDA/APHIS on 28 October 2005. Soybean rust was identified in subsequent surveys of soybean fields and leaf samples submitted by North Carolina Cooperative Extension Agents in an additional 15 counties. These samples also were assayed using a traditional PCR protocol and by the enzyme-linked immunosorbent assay protocol included in the EnviroLogix QualiPlate kit (Portland, ME) for soybean rust. Ten soybean specimens from 10 sites were confirmed positive by these methods. Disease was not found on three kudzu samples, although one kudzu sample was adjacent to a soybean field that was positive for P. pachyrhizi. Although soybean rust was eventually detected in 18 North Carolina counties in 2005, no soybean yield loss occurred since the pathogen was detected when more than 80% of the soybean crop was mature. To our knowledge, this is the first report of P. pachyrhizi in North Carolina and the northern most find on soybean in the continental United States in 2005. References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) R. W. Schneider et al. Plant Dis. 89:774 2005.

Factors associated with abnormal Pap results in systemic lupus erythematosus.

OBJECTIVE: Previous studies have suggested that women with systemic lupus erythematosus (SLE) are at greater risk for cervical dysplasia than are women in the general population. However, the factors associated with abnormal Pap test results in SLE have not been well studied. We therefore aimed to determine the factors associated with lifetime occurrence of an abnormal Pap test in women with SLE, and the influence of immunosuppressive exposure on the odds of abnormal Pap test results occurring after diagnosis of SLE. METHODS: Data were pooled from SLE cohorts from three centres. Self-report data were available on smoking, reproductive history, use of oral contraceptives (OC), history of sexually transmitted diseases (STDs) and whether the subjects had had cervical dysplasia on Pap testing. Logistic regression was used to examine the effect of these variables on the lifetime odds of cervical dysplasia. We then generated the adjusted odds ratio (OR) for the effect of immunosuppressive exposure on cervical dysplasia occurring after diagnosis of SLE. RESULTS: History of STDs and use of OCs were positively associated with reports of cervical dysplasia in adjusted analyses. The ORs for the effect of immunosuppressives on abnormal Pap test occurrence (adjusted for race, age, smoking, nulliparity, OC use and history of STDs) after diagnosis of SLE was 1.6 (95% CI 1.0, 2.7). CONCLUSIONS: A history of STDs and use of OCs were associated with abnormal Pap reports in this SLE sample. Immunosuppressive exposure may confer further risk to women with SLE.

Hormonal exposures and breast cancer in a sample of women with systemic lupus erythematosus.

OBJECTIVES: To determine if breast cancer risk in women with SLE is modified by a history of exposure to hormone replacement therapy (HRT) or oral contraceptives (OC), after adjusting for other risk factors. METHODS: Data were pooled from SLE cohorts at three centres. For each female cohort member (n = 871), the probability of developing breast cancer was estimated from factors (age, parity, age at first live birth, age of menarche, personal history of benign breast disease, family history) in the Gail model, an established tool for predicting breast cancer risk. From these probabilities, the expected number of breast cancers for the cohort was estimated. Actual occurrence of cases was determined by linkage with regional cancer registries. Standardized incidence ratios (SIRs; ratio of cancers observed to expected) were calculated, with subgroup analyses according to HRT and OC exposure. RESULTS: In the cohort, 15 breast cancers occurred vs 7.2 predicted [SIR 2.1, 95% confidence interval (CI) 1.1, 3.5]. When controlling for Gail model risk factors, estimates were similar for women never exposed to HRT vs those exposed to HRT. Adjusted SIR estimates appeared similar also for women exposed or not exposed to OC. CONCLUSIONS: Although not definitive, the data suggest that the breast cancer experience in this sample is not completely explained by factors such as reproductive and family history, or by exogenous hormonal exposures. Other determinants, including medication exposures or genetic factors (possibly related to oestrogen receptors or metabolism) may be important. Variations in these factors might explain why an elevated risk of breast cancer has not been apparent in all SLE populations.

Maximal exercise as a countermeasure to orthostatic intolerance after spaceflight.

UNLABELLED: Previous investigators have suggested that maximal exercise performed 24 h before the end of bed rest, a spaceflight analog, restores prebed rest plasma volume, baroreflex responses, and orthostatic tolerance. PURPOSE: In this case report, we examined the effect of a similar exercise protocol 24 h before a Shuttle landing on the orthostatic responses of four crewmembers (EX) after spaceflights of 8-14 d. Four additional crewmembers (CON) served as controls and did not perform exercise during the final day of the flight. METHODS: Each crewmember performed a 10-min stand test approximately 10 d before launch (L-10) and within 1-2 h of landing (R+0). Cardiac stroke volume was measured (Doppler ultrasound) supine and during each min of standing for three EX and three CON subjects. RESULTS: Preflight, all crewmembers completed the stand test and each group had similar heart rate and blood pressure responses. Postflight, all subjects also completed the 10-min stand test. Each group had similarly elevated supine and standing heart rates, elevated diastolic and mean arterial blood pressures, and reduced pulse pressures compared to L-10. However, postflight cardiac output, mean +/- SEM, (EX: 4.5+/-0.6 L x min(-1); CON: 3.1+/-0.3 L x min(-1)) and stroke volume (EX: 43+/-7 mL x beat; CON: 30+/-6 mL x beat) were higher after 10 min standing in the EX subjects compared to CON subjects. CONCLUSIONS: For these four crewmembers, maximal exercise performed 24 h before landing may have helped maintain stroke volume but did not maintain heart rate and blood pressure responses during standing compared to preflight.

The use of alternative medical therapies in patients with systemic lupus erythematosus. Trination Study Group.

OBJECTIVE: As part of an ongoing study of health resource utilization and diminished productivity in patients with systemic lupus erythematosus (SLE), the use of alternative medical therapies was assessed. METHODS: A cohort of 707 patients with SLE from 3 countries completed questionnaires on demographics, social support, health status (using the Short Form 36 health survey), satisfaction with health care, health resource utilization (conventional resources and alternative therapies), and time losses in labor market and non-labor market activities. Annual direct and indirect costs (1997 Canadian dollars) were calculated and compared for users and nonusers of alternative medical therapies. RESULTS: Among the 707 patients, 352 (49.8%) were found to use alternative therapies and at similar rates across Canada, the United States, and the United Kingdom. Users were younger and better educated than nonusers, exhibited poorer levels of self-rated health status and satisfaction with medical care, and had minimal to no objective evidence of worse disease (according to the revised Systemic Lupus Activity Measure instrument). The mean of log direct medical costs for conventional resources was higher for users of select alternative therapies compared with nonusers. In a logistic regression, neither the number of alternative therapies used nor the individual therapy increased the probability of incurring indirect costs. CONCLUSION: The use of alternative medical therapies is common in patients with SLE. Users of many alternative medical therapies accrue greater conventional medical costs compared with nonusers. The use of alternative medical therapy may be a marker for care-seeking behavior associated with higher consumption of conventional medical resources in the absence of demonstrable additional morbidity and should be considered in future cost analyses of patients with SLE.

Owning genetic information and gene enhancement techniques: why privacy and property rights may undermine social control of the human genome.

In this article I argue that the proper subjects of intangible property claims include medical records, genetic profiles, and gene enhancement techniques. Coupled with a right to privacy these intangible property rights allow individuals a zone of control that will, in most cases, justifiably exclude governmental or societal invasions into private domains. I argue that the threshold for overriding privacy rights and intangible property rights is higher, in relation to genetic enhancement techniques and sensitive personal information, than is commonly suggested. Once the bar is raised, so-to-speak, the burden of overriding it is formidable. Thus many policy decisions that have been recently proposed or enacted--citywide audio and video surveillance, law enforcement DNA sweeps, genetic profiling, national bans on genetic testing and enhancement of humans, to name a few--will have to be backed by very strong arguments.

Inflight exercise affects stand test responses after space flight.

PURPOSE: The purpose of this study was to determine whether exercise performed by Space Shuttle crew members during short-duration space flights (9-16 d) affects the heart rate (HR) and blood pressure (BP) responses to standing within 2-4 h of landing. METHODS: Thirty crew members performed self-selected inflight exercise and maintained exercise logs to monitor their exercise intensity and duration. Two subjects participated in this investigation during two different flights. A 10-min stand test, preceded by at least 6 min of quiet supine rest, was completed 10-15 d before launch (PRE) and within 4 h of landing (POST). Based upon their inflight exercise records, subjects were grouped as either high (HIex: > or = 3 times/week, HR > or = 70% HRmax, > or = 20 min/session, N = 11), medium (MEDex: > or = 3 times/week, HR < 70% HRmax, > or = 20 min/session, N = 10), or low (LOex: < or = 3 times/week, HR and duration variable, N = 11) exercisers. HR and BP responses to standing were compared between groups (ANOVA, P < or = 0.05). RESULTS: There were no PRE differences between the groups in supine or standing HR and BP. Although POST supine HR was similar to PRE, all groups had an increased standing HR compared with PRE. The increase in HR upon standing was significantly greater after flight in the LOex group (36 +/- 5 bpm) compared with HIex or MEDex groups (25 +/- 1 bpm; 22 +/- 2 bpm). Similarly, the decrease in pulse pressure (PP) from supine to standing was unchanged after space flight in the MEDex and HIex groups but was significantly greater in the LOex group (PRE: -9 +/- 3; POST: -19 +/- 4 mm Hg). CONCLUSIONS: Thus, moderate to high levels of inflight exercise attenuated HR and PP responses to standing after space flight.

Sample size considerations for superiority trials in systemic lupus erythematosus (SLE).

For reasons of efficiency and ethics, sample size calculations are an important part of the design of all clinical trials. This paper highlights the statistical issues inherent to the estimation of sample size requirements in superiority trials particular to SLE. Calculations based on statistical power for testing hypotheses have historically been the method of choice for sample size determination in clinical trials. The advantages of using confidence intervals (CI's) rather than P-values in reporting results of clinical trials is now well established. Since the design of a trial should match the analysis that will eventually be performed, sample size methods based on ensuring accurate estimation of important parameters via sufficiently narrow CI widths should be preferred to methods based on hypothesis testing. Methods and examples are given for sample size calculations for continuous and dichotomous outcomes from both a power and confidence interval width viewpoint. An understanding of sample size calculations in association with expert statistical consultation will result in better designed clinical trials that accurately estimate clinically relevant differences between treatment outcomes, thereby furthering the treatment of patients with SLE.

Carbon dioxide accumulation, walking performance, and metabolic cost in the NASA launch and entry suit.

BACKGROUND: In the event of an emergency on landing, Space Shuttle crewmembers while wearing the Launch and Entry Suit (LES) must stand, move to the hatch, exit the spacecraft with the helmet visor closed breathing 100% O2, and walk or run unassisted to a distance of 380 m upwind from the vehicle. The purpose of this study was to characterize the inspired CO2 and metabolic requirements during a simulated unaided egress from the Space Shuttle in healthy subjects wearing the LES. METHODS: As a simulation of a Shuttle landing with an unaided egress, 12 male subjects completed a 6-min seated pre-breathe with 100% O2 followed by a 2-min stand and 5-min walking at 1.56 m x s(-1) (5.6 km x h(-1), 3.5 mph) with the helmet visor closed. During walks with four different G-suit pressures (0.0, 0.5, 1.0, 1.5 psi; 3.4, 6.9, 10.3 kPa), inspired CO2 and walking time were measured. After a 10-min seated recovery, subjects repeated the 5-min walk with the same G-suit pressure and the helmet visor open for the measurement of metabolic rate (VO2). RESULTS: When G-suit inflation levels were 1.0 or 1.5 psi, only one-third of our subjects were able to complete the 5-min visor-closed walk after a 6-min pre-breathe. Inspired CO2 levels measured at the mouth were routinely greater than 4% (30 mmHg) during walking. The metabolic cost at the 1.5 psi G-suit inflation was over 135% of the metabolic cost at 0.0 psi inflation. CONCLUSION: During unaided egress, G-suit inflation pressures of 1.0 and 1.5 psi resulted in elevated CO2 in the LES helmet and increased metabolic cost of walking, both of which may impact unaided egress performance. Neither the LES, the LES helmet, nor the G-suit were designed for ambulation. Data from this investigation suggests that adapting flight equipment for uses other than those for which it was originally designed can result in unforeseen problems.

Survival of women with surgical stage II endometrial cancer.

OBJECTIVE: The aim of this study was to report survival and determine prognostic factors and results of therapy in women with surgical stage II endometrial cancer. METHODS: Forty-eight consecutive women with surgical stage II endometrial cancer treated at the University of Vermont between March 1984 and March 1998 were reviewed. Patients' characteristics, surgical procedure, postoperative treatment and its complications, and tumor recurrence and its treatment were recorded. In addition, a formal review of their pathological material for confirmation of the diagnosis was performed. RESULTS: The median duration of follow-up was 6.2 years. Three patients (6.3%) had tumor recurrence and two (4.2%) died of their disease. The estimated 5-year overall survival and disease-free survivals were 92.1% (SE = 5.5%, 95% confidence interval: 81.3, 100%) and 89.9% (SE = 5.8%, 95% confidence interval: 78.5%, 100%), respectively. None of the patients treated by total abdominal hysterectomy followed by both whole pelvic and vaginal cuff radiation therapy (the main line of treatment for patients in whom cervical involvement was diagnosed following hysterectomy, n = 20) or by radical hysterectomy (the main line of treatment for patients in whom cervical involvement was known before hysterectomy, n = 11) had tumor recurrence. Three of 17 (17.6%) patients treated with total abdominal hysterectomy followed by either whole pelvic (n = 13) or vaginal cuff (n = 4) radiation therapy had tumor recurrence. The difference between those two groups was statistically significant (0/31 versus 3/17, P = 0.02). There was no difference in survival among women with stage IIA and IIB or women who underwent radical abdominal hysterectomy and those who underwent total abdominal hysterectomy with postoperative pelvic and vaginal cuff radiation. Morbidity secondary to therapy was mild. Age, depth of myometrial invasion, tumor histology, and grade were not significantly related to recurrence. CONCLUSIONS: Survival of women with surgical stage II endometrial cancer is excellent especially among those treated with total abdominal hysterectomy followed by both pelvic and vaginal cuff radiotherapy or by radical abdominal hysterectomy.

Can health utility measures be used in lupus research? A comparative validation and reliability study of 4 utility indices.

OBJECTIVE: To assess validity and reliability of 4 utility indices in patients with systemic lupus erythematosus (SLE). METHODS: Twenty-five patients with stable SLE underwent assessment of disease activity [Systemic Lupus Disease Activity Measure (SLAM-R) and SLE Disease Activity Index (SLEDAI)] and damage [Systemic Lupus Collaborating Clinics/American College of Rheumatology Damage Index (SLICC/ACR DI)] and completed a health survey [Medical Outcome Survey Short Form-36 (SF-36)] and 4 utility measures: the visual analog scale (VAS), the time trade-off (TTO), the standard gamble (SG), and the McMaster Health Utilities Index Mark 2 (HUI2). To assess validity, Pearson's correlations were calculated between the SF-36 subscales and the utility measures. To assess reliability, intraclass correlations or kappa coefficients were calculated between first and second assessments, performed from 2 to 4 weeks apart, in patients without important clinical change in disease activity. RESULTS: Disease activity from a SLAM-R varied from 0 to 14 (median = 4) and SLEDAI from 0 to 18 (median = 0). All subscales of the SF-36 correlated well with the VAS [lowest r = 0.56, 95% confidence interval (CI) (0.17, 0.80)] and poorly with the SG [maximum r = 0.41, CI (-0.01, 0.70); minimum r = 0.10, CI (-0.32, 0.50)]. The subscales of bodily pain (r = 0.56), mental health (r = 0.45), physical functioning (r = 0.62), role-emotional (r = 0.47), social functioning (r = 0.49) and vitality (r = 0.44) correlated significantly with TTO. All subscales correlated significantly [lowest r = 0.48, CI (0.09, 0.75)] with the HUI2 index of pain. Intraclass correlations for the VAS (ICC = 0.67) and TTO (ICC = 0.60) were good. They were fair for the SG (ICC = 0.45). The kappa coefficient was poor (0.32) for the HUI attribute of pain, but varied from fair (0.46) to excellent (0.88) for the remaining attributes. Regression analysis showed that a model incorporating the SLAM-R value and SF-36 subset of mental health was a good predictor of VAS and TTO utility measures. CONCLUSION: The VAS, TTO, and to some extent, the HUI2, when compared with the SF-36 health survey, are valid and reliable measures to assess health related quality of life in a group of patients with SLE and may be useful for future research in this population. On the basis of these results the usefulness of the SG is questionable in these patients.

Validity of a heart rate monitor during work in the laboratory and on the Space Shuttle.

Accurate heart rate measurement during work is required for many industrial hygiene and ergonomics situations. The purpose of this investigation was to determine the validity of heart rate measurements obtained by a simple, lightweight, commercially available wrist-worn heart rate monitor (HRM) during work (cycle exercise) sessions conducted in the laboratory and also during the particularly challenging work environment of space flight. Three different comparisons were made. The first compared HRM data to simultaneous electrocardiogram (ECG) recordings of varying heart rates that were generated by an ECG simulator. The second compared HRM data to ECG recordings collected during work sessions of 14 subjects in the laboratory. Finally, ECG downlink and HRM data were compared in four astronauts who performed cycle exercise during space flight. The data were analyzed using regression techniques. The results were that the HRM recorded virtually identical heart rates compared with ECG recordings for the data set generated by an ECG simulator. The regression equation for the relationship between ECG versus HRM heart rate data during work in the laboratory was: ECG HR = 0.99 x (HRM) + 0.82 (r2 = 0.99). Finally, the agreement between ECG downlink data and HRM data during space flight was also very high, with the regression equation being: Downlink ECG HR = 1.05 x (HRM) -5.71 (r2 = 0.99). The results of this study indicate that the HRM provides accurate data and may be used to reliably obtain valid data regarding heart rate responses during work.

Determining blood and plasma volumes using bioelectrical response spectroscopy.

We hypothesized that an electric field (inductance) produced by charged blood components passing through the many branches of arteries and veins could assess total blood volume (TBV) or plasma volume (PV). Individual (N = 29) electrical circuits (inductors, two resistors, and a capacitor) were determined from bioelectrical response spectroscopy (BERS) using a Hewlett Packard 4284A Precision LCR Meter. Inductance, capacitance, and resistance from the circuits of 19 subjects modeled TBV (sum of PV and computed red cell volume) and PV (based on 125I-albumin). Each model (N = 10, cross validation group) had good validity based on 1) mean differences (-2.3 to 1.5%) between the methods that were not significant and less than the propagated errors (+/- 5.2% for TBV and PV), 2) high correlations (r > 0.92) with low SEE (< 7.7%) between dilution and BERS assessments, and 3) Bland-Altman pairwise comparisons that indicated "clinical equivalency" between the methods. Given the limitation of this study (10 validity subjects), we concluded that BERS models accurately assessed TBV and PV. Further evaluations of the models' validities are needed before they are used in clinical or research settings.

Cognitive moderators of outcome following traumatic brain injury: a conceptual model and implications for rehabilitation.

This paper presents a conceptual model describing the relationships between quality of life outcomes following traumatic brain injury (TBI), coping patterns, and beliefs regarding self-efficacy to assist health-care professionals in understanding the complexity of social and psychological sequelae of TBI. The mode hypothesizes that long-lasting cognitive, behavioural, emotional psychiatric, and interpersonal after-effects of TBI may create a real life 'learned helplessness' with consequent deficits in coping, and altered locus of control beliefs. As a result, TBI patients are at risk for developing self-limiting belief systems about their effectiveness in altering significant events that may result in over-generalizing the effects that TBI has in their day-to-day lives. Subsequently, a feedback loop may be set up where their beliefs in not being able to influence outcomes are not tested, life chances are further restricted, outcomes are suboptimal, and quality of life is reduced. The clinical and theoretical implications of this model are discussed, and an expanded model with future research directions is suggested.

Does bed rest produce changes in orthostatic function comparable to those induced by space flight?

Use of bed rest to simulate microgravity exposure is not well validated. We compared heart rate (HR) and blood pressure (BP) responses to standing in bed-rest (BR) subjects (n=11) to those of two astronaut groups. One astronaut group (n=28) fluid loaded (FL) before landing by consuming a water and salt tablet mixture, the second astronaut group (n=8) did not (NL). Bed-rest or microgravity exposure lasted approximately 7.0 days. Preexposure, the responses to standing did not differ between groups. Postexposure, all groups demonstrated an increased HR response (p<0.01), a decreased SBP response (p<0.05), no change in DBP response, and a reduced PP response (p<0.05) compared to preexposure. Change in HR response was lowest for the FL group, presumably due to increased plasma volume induced by fluid consumption. These findings generally support bed rest as a valid simulator of microgravity.