Substantial Floor Research Articles

The Oxford Knee Score: Compared performance before and after knee replacement

Self-administered quality-of-life questionnaires are now crucial to the evaluation of orthopaedic surgical patient-reported outcomes, as they reflect patient satisfaction. The Oxford Knee Score (OKS) is a validated instrument that is widely used to assess outcomes of knee osteoarthritis surgery. The relevance of the OKS (comprehension and relevance of the items and responses, and internal and external validity) and its discriminating performance measured based on the ceiling and floor threshold effects are better before than after knee replacement surgery. We included 200 patients (100 scheduled for knee replacement and 100 having had knee replacement more than 1 year earlier). The OKS questionnaire was handed to each patient during the first surgeon visit or during a follow-up visit. The American Knee Society (AKS) score was determined simultaneously. The mean OKS was 43.7 (range, 21-56; SD, 6.9) before surgery and 20.5 (range, 12-45; SD, 5.6) after surgery. The floor effect was absent (0%) before surgery and substantial (33%) after surgery; a weak ceiling effect (7%) was noted before surgery and no ceiling effect after surgery. Internal consistency of the OKS was excellent. The OKS correlated negatively with the AKS knee and functional scores, both before and after surgery. The OKS is well-suited to the evaluation of knee function both before and after knee replacement surgery. Before surgery, the absence of substantial floor and ceiling effects lead to excellent discrimination. After surgery, the substantial floor effect limits the ability to discriminate among the best results. Efforts should be made to develop more demanding scoring systems. Level 2. Exploratory cohort study with universally applied reference standards.

Comparison of Skindex-29, Dermatology Life Quality Index, Psoriasis Disability Index and Medical Outcome Study Short Form 36 in patients with mild to severe psoriasis

Severity assessment of patients with psoriasis is a critical issue. Classical clinical assessment has recently been combined with quality of life (QoL) scores, but several instruments are used. Moreover, studies have focused on patients with moderate to severe psoriasis. To compare the characteristics of QoL instruments in patients with the full range of psoriasis severity attending dermatology clinics. Observational, prospective, multicentre study. Patients completed Skindex-29 (anchor) and a second instrument randomly selected from Dermatology Life Quality Index (DLQI), Psoriasis Disability Index (PDI) and Medical Outcome Study Short Form 36 (SF-36). Demographic data, Psoriasis Area and Severity Index and affected body surface area were not different between the three groups. Skindex-29 showed a weak but significant correlation with clinical severity; only PDI showed similar correlation. PDI, DLQI and SF-36 showed a substantial floor effect in patients with mild to severe psoriasis. Skindex-29 showed strong correlations with the other three QoL instruments. SF-36 was more sensitive than the other instruments in detecting worse QoL in male patients. Skindex-29 has better sensitivity to clinical severity with minimal floor effect, and covers the main domains explored by the other three QoL instruments in patients with mild to severe psoriasis.

Minimum toe clearance adaptations to floor surface irregularity and gait speed

Toe speed during gait generally nears its maximum while its height reaches a local minima approximately halfway through swing phase. Trips are thought to frequently occur at these local minima (minimum toe clearance or MTC events) and trip risk has been quantified using the minimum distance between the toe and ground here (MTC). This study investigated MTC on floor surfaces with and without multiple small obstacles. After shoes and floor surfaces were digitized, 14 unimpaired subjects (half women) each traversed a 4.88 m walkway 4 times at slow, preferred, and fast speeds across surfaces with no obstacles, visible obstacles, and hidden obstacles. Both surfaces with obstacles had the same random obstacle configuration. Shoe and body segment motions were tracked using passive markers and MTC and joint kinematics calculated. All MTC and kinematic variables tested significantly increased with faster instructed gait speed except the likelihood of MTC event occurrence (local minima in minimum toe clearance trajectory when foot is in upper quartile of speed). MTC events were less frequent for swing phases on surfaces with obstacles (80% vs. 98% for no obstacles). MTC values, when present, were doubled by the presence of visible obstacles (22.2±7.3 mm vs. 11.1±5.7 mm) and further increased to 26.8±7.1 mm when these obstacles were hidden from view (all comparisons p≤0.0003). These substantial floor surface-related changes in MTC event occurrences and values resulted from alterations in toe- and heel-clearance trajectories caused by subtle but significant changes in joint kinematics that did not exceed 10% each joint's swing phase range of motion.

Which Is More Valid for Stroke Patients: Generic or Stroke-Specific Quality of Life Measures?

Background: It remains unclear whether a generic or specific health-related quality of life (HRQOL) measure is more valid for stroke. Aim: The aim of this study is to compare the validity of SF-36, a generic measure, and HRQOL in stroke patients (HRQOLISP), a stroke-specific measure, for assessing post-stroke HRQOL. Methods: The validity of HRQOLISP and SF-36 was compared in a cross-sectional study of 100 stroke survivors. The Stroke Levity Scale and modified Rankin Scale were applied to measure stroke severity and disability, respectively. Results: Both measures exhibited adequate ‘known-groups’ and construct validity. However, the SF-36 lacked content validity for the cognitive domain and personal constructs including spiritual functioning. Most SF-36 subscales had substantial floor or ceiling effects. The HRQOLISP demonstrated better content and internal consistency validity and no significant floor or ceiling effect. Conclusions: Like other stroke-specific measures, HRQOLISP was better than SF-36 in most parameters of validity considered. The SF-36 is designed for comparison among different diseases and may not be suitable for clinical trials or studies of internal adaptation, cognitive or spiritual functioning in stroke. This is because it lacks content validity for these domains and may underestimate health changes in most subscales.

Trace and rare-earth element geochemistry: A tool for petrogenetic and geotectonic modeling of ensimatic ortho-amphibolites from Pan-African belt of Obudu Plateau, Southeastern Nigeria

A model for the petrogenetic affinity and original geotectonic setting of ortho-amphibolites from the Obudu Plateau was tested using the distribution patterns of trace and rare-earth elements from the geochemical analyses of twelve representative amphibolite samples. Discrimination plots, normalized patterns of the incompatible trace elements against average MORB, low ratios of Ba/Nb (9-23) and Ba/Ta (130-327) and other geochemical characteristics suggest that the protoliths were dominantly of tholeiitic MORB composition. The values of the ratios of La/Ta (8.13-10.8), Rb/Sr (0.04-0.07), Th/U (mainly 4.43-5.43) and Hf/Ta (2.35-2.88) further indicate that the ortho-amphibolites demonstrate E-type MORB characteristics. These features are related to substantial ocean floor divergent tectonic boundary setting rather than marginal basin tectonic setting. This evolutionary pattern appears to be controlled by limited progressive partial melting and fractional crystallization of a single mantle source region, irrespective, however, of variations due to local source heterogeneities. The tholeiitic magmas were most probably generated by hotspot activities on the constructive plate margins and subsequently modified by subduction-related low-K tholeiitic chemistry due to narrowing of a proto oceanic basin between the West African craton and eastern Sahara plate. A likely model, therefore, is that the amphibolites of the Obudu Plateau represent ophiolitic suites with characteristics of enriched mid-ocean floor tholeiites, which were deformed and metamorphosed during a reversed plate motion involving subduction and collision within the Obudu Plateau in the Pan-African orogenic episode.

Tradução e validação de um questionário de avaliação de qualidade de vida em AIDS no Brasil

To translate the HIV/AIDS-Targeted Quality of Life Instrument (HAT-QoL) into Brazilian Portuguese, culturally adapt it, and evaluate its psychometric properties (validity and reliability) as a Brazilian version. This cross-sectional study was carried out at the laboratory of infectious diseases at Escola Paulista de Medicina (Universidade Federal de São Paulo). Data were collected on clinical and sociodemographic characteristics of 106 HIV-infected individuals who answered the HAT-QoL and the SF-36. Pearson's correlation coefficient was used to measure construct validity. Reliability was assessed using Cronbach's alpha and intraclass correlation coefficients. The sample was 70.8% male. The mean age was 39.9 years, with 40.5% of the participants being homosexual or bisexual. Eleven (10.4%) patients had a CD4 cell count <or= 200 cells/mm(3). A substantial ceiling effect was observed in 7 of 9 HAT-QoL domains (overall function, life satisfaction, health worries, medication worries, HIV acceptance, provider trust, and sexual function). Sexual function was the domain with the highest ceiling effect (63.2%). A substantial floor effect (30.2%) was observed for financial worries. Statistically significant associations were observed between the HAT-QoL domains and clinical and sociodemographic characteristics, as well as with SF-36 domains. Internal consistency was satisfactory (Cronbach's alpha = 0.73-0.90). Inter- and intra-observer reproducibility was very high (0.87-0.98 and 0.82-0.97, respectively). The Brazilian Portuguese version of the HAT-QoL is valid, reliable, and may contribute to evaluating the impact of HIV infection on the quality of life of patients in Brazil.

Validation and cultural adaptation of a German version of the Physicians' Reactions to Uncertainty scales

BackgroundThe aim of the study was to examine the validity of a translated and culturally adapted version of the Physicians' Reaction to Uncertainty scales (PRU) in primary care physicians.MethodsIn a structured process, the original questionnaire was translated, culturally adapted and assessed after administering it to 93 GPs. Test-retest reliability was tested by sending the questionnaire to the GPs again after two weeks.ResultsThe principal factor analysis confirmed the postulated four-factor structure underlying the 15 items. In contrast to the original version, item 5 achieved a higher loading on the 'concern about bad outcomes' scale. Consequently, we rearranged the scales. Good item-scale correlations were obtained, with Pearson's correlation coefficient ranging from 0.56–0.84. As regards the item-discriminant validity between the scales 'anxiety due to uncertainty' and 'concern about bad outcomes', partially high correlations (Pearson's correlation coefficient 0.02–0.69; p < 0.001) were found, indicating an overlap between both constructs. The assessment of internal consistency revealed satisfactory values; Cronbach's alpha of the rearranged version was 0.86 or higher for all scales. Test-retest-reliability, assessed by means of the intraclass-correlation-coefficient (ICC), exceeded 0.84, except for the 'reluctance to disclose mistakes to physicians' scale (ICC = 0.66). In this scale, some substantial floor effects occurred, with 29.3% of answers showing the lowest possible value.ConclusionDealing with uncertainty is an important issue in daily practice. The psychometric properties of the rearranged German version of the PRU are satisfying. The revealed floor effects do not limit the significance of the questionnaire. Thus, the German version of the PRU could contribute to the further evaluation of the impact of uncertainty in primary care physicians.

Cultural adaptation and validation of a German version of the Arthritis Impact Measurement Scales (AIMS2)

To validate a translated and culturally adapted version of the Arthritis Impact Measurement Scale (AIMS) 2 in primary care patients with osteoarthritis (OA) of the hip and knee. The AIMS2 was translated into German and culturally adapted. The questionnaire then was administered to 220 primary care patients with OA of the knee or hip. Two hundred and nine questionnaires were returned and analysed. Test-retest reliability was tested in 50 randomly selected patients, of those 42 completed the questionnaire after 2 weeks for a second time. Item-scale correlations were reasonably good as well as the discriminative power of separate scales. The assessment of internal consistency reliability also revealed satisfactory values; Cronbach's alpha was 0.77 or higher for all scales. The test-retest reliability, estimated in an intraclass correlation coefficient (ICC), exceeded 0.90, except the "social activities" scale (0.87). Since only patients with OA of the lower limb were enrolled, substantial floor effects occurred in the "arm function" (28.2%) and the "hand and finger function" scale (29.2%). The principal factor analysis confirmed the postulated three-factor structure with a physical, physiological and social dimension, explaining 48.5%, 13.9% and 6.8% of the variation, respectively. External validity was assessed by calculating correlations to the Western Ontario and MacMaster (WOMAC) osteoarthritis questionnaire a pain visual analogue scale (VAS) and the Kellgren score as well as to disease duration. Spearman's "R" achieved satisfactory values for the corresponding WOMAC scales and the pain-VAS. Correlations with disease duration as well as with the radiological grading were low. The GERMAN-AIMS2 is a reliable and valid instrument to assess the quality of life (QoL) in primary care patients suffering from OA.

Evidence‐based guidelines for using the Short Form 36 in cervical dystonia

We aimed to provide evidence-based guidelines for using the Short Form 36 (SF-36) as an outcome measure in cervical dystonia (CD). To do this, we tested the hypothesized relationships between items, scales, and summary measures of the SF-36 using psychometric analyses in data from a postal survey of 235 people with CD. Although the majority of subscales performed adequately, the Role Physical and Role Emotional subscales had substantial floor and/or ceiling effects. Evidence did not support computing SF-36 Physical and Mental Component Summary scores. We propose guidelines that include the recommendation that these subscale and summary scores should be reported with caution.

Development and validation of the Edmonton Ankylosing Spondylitis Metrology Index

Assessment of spinal and hip mobility has been recommended by the Assessments in Ankylosing Spondylitis (AS) Working Group for clinical trials and record keeping, although suggested measures primarily reflect structural damage. Our objective was to validate a simple, 4-item composite measure of spinal and hip mobility, the Edmonton AS Metrology Index (EDASMI). We assessed the EDASMI and the Bath AS Metrology Index (BASMI) using a total of 263 patients from 3 countries: Canada (n = 205), Australia (n = 29), and Colombia (n = 29). Intra- and interobserver reliability were assessed in a subset of 44 patients. Construct validity with respect to disease activity (Bath AS Disease Activity Index [BASDAI]), function (Bath AS Functional Index [BASFI]), and structural damage (modified Stoke AS Spinal Score [mSASSS]) was analyzed using correlation and hierarchical regression. Responsiveness was assessed in a subset of 33 patients who received either anti-tumor necrosis factor alpha therapy (n = 26) or pamidronate (n = 7) over 24 weeks. In contrast to the EDASMI, BASMI scores covered a limited range, with 70% of patients demonstrating a score < or =3 (range 0-10) and 4 of 5 individual measures demonstrating substantial floor effects. Both measures were highly reliable (intraclass correlation coefficient >0.90) and demonstrated similar construct validity (EDASMI correlated with disease duration [0.52], BASDAI [0.24], BASFI [0.61], Bath Ankylosing Spondylitis Radiology Index [0.79], mSASSS [0.75]; P < 0.001 for all). The change in EDASMI score was significant after 24 weeks of therapy (standardized response mean 0.40; P = 0.03), but change in the BASMI was not significant. The EDASMI is a simple, rapid, and reliable tool for the assessment of spinal mobility in AS that is responsive to therapeutic intervention.

Danish version of the Oswestry Disability Index for patients with low back pain. Part 1: Cross-cultural adaptation, reliability and validity in two different populations

Over the past 10 years, a plethora of back-specific patient-orientated outcome measures have appeared in the literature. Standardisation has been advocated by an expert panel of researchers proposing a core set of instruments. Of the condition-specific questionnaires the Oswestry Disability Index (ODI) is recommended for use with low back pain (LBP) patients. To date, no Danish version of the ODI exists which has been cross-culturally adapted, validated and published in the peer-reviewed literature. A cross-cultural adaptation and validation of the ODI for the Danish language was carried out according to established guidelines: 233 patients [half of the patients were seen in the primary sector (PrS) and half in the secondary sector (SeS) of the Danish health care system] with LBP and/or leg pain completed a questionnaire booklet at baseline, 1 day or 1 week and 8 weeks follow-up. The booklet contained the Danish version of the ODI, along with the Roland Morris Disability Questionnaire, the LBP Rating Scale, the SF36 (physical function and bodily pain scales) and a global pain rating. For the ODI test-retest analysis (93 stable patients) resulted in an intraclass correlation coefficient of 0.91, a mean difference of 0.8 and 95% limits of agreements of - 11.5 to + 13. Thus, a worsening greater than 12 points and improvement greater than 13 points can be considered a "real" change above the measurement error. A substantial floor effect was found in PrS patients (14.1%). The ODI showed satisfactory cross-sectional discriminant validity when compared to the external measures. Concurrent validity of the ODI revealed: (a) a 10% and 21% lower ODI score compared to the disability and pain measures, respectively, (b) a poorer differentiation of patient disabilities and (c) an acceptable individual ODI score level compared to the external measures. Longitudinal external construct validity showed moderate correlations (range 0.56-0.78). We conclude that the Danish version of the ODI is both a valid and reliable outcome instrument in two LBP patient populations. The ODI is probably most appropriate for use in SeS patients.

Evaluation and cultural adaptation of a German version of the AIMS2-SF questionnaire (German AIMS2-SF)

The aim of the study was to examine the validity of a translated and culturally adapted version of the Arthritis Impact Measurement Scales 2, Short Form (AIMS2-SF) in patients suffering from osteoarthritis (OA) in primary care. A structured procedure was used for the translation and cultural adaptation of the AIMS2-SF into German. The questionnaire was administered to 220 primary care patients with OA of the knee or hip. Test-retest reliability was tested in 35 randomly selected patients, who received the questionnaire a second time after 1 week. The physical scale of the original AIMS2-SF was divided into an 'upper body limitations' scale and a 'lower body limitations' scale. With values ranging from 0.52 to 0.97 for Pearson's r, item-scale correlations were reasonably good. The discriminative power of separate scales was also good, reflected in low values for correlation between different scales, indicating little redundancy. Only two items (13 and 15) referring to the symptom scale showed item-scale correlation of r = 0.72 and r = 0.67, respectively with the lower body limitation scale. The assessment of internal consistency reliability also revealed satisfactory values: Cronbach's alpha was > or =0.83 for all scales, except for the social interaction scale (0.66). The test-retest reliability, estimated as the intraclass correlation coefficient (ICC), exceeded 0.85 except for the affect scale (0.72). Substantial floor effects occurred in the upper limb scale (33.8%). Principal factor analysis confirmed the postulated three-factor structure with physical, physiological and social dimensions, explaining 49.8, 14.1 and 6.4% of the variation, respectively. The assessment of external validity revealed satisfactory correlations with the corresponding WOMAC (Western Ontario and McMaster Universities Arthrosis Index) scales. As expected, correlations with radiological grading were moderate to low. The correlation with the physician's assessment was high in the scales that were dominated by physical factors, but rather low in the areas of health, which were found to be dominated by psychological or social factors. The German AIMS2-SF is a reliable and valid instrument to assess the quality of life in primary care patients suffering from OA. When addressing the different impacts of OA, the physical scale should be divided into an upper body scale and a lower body scale. The floor and ceiling effects revealed are in accordance with the disease characteristics of the study sample and do not limit the significance of the questionnaire.

Functional Independence Domains in Patients Receiving Rehabilitation in Skilled Nursing Facilities: Evaluation of Psychometric Properties

Jette DU, Warren RL, Wirtalla C. Functional independence domains in patients receiving rehabilitation in skilled nursing facilities: evaluation of psychometric properties. Arch Phys Med Rehabil 2005;86:1089–94. Objective To provide evidence for the validity of using FIM items to derive 4 domains of functional independence (mobility, activities of daily living [ADLs], sphincter management, executive function) in patients receiving rehabilitation in skilled nursing facilities (SNFs). Design A retrospective analysis of secondary data using data from a privately owned administrative dataset. Setting Seventy SNFs under contract with SeniorMetrix Inc health plan clients. Participants Patients (N=7536) with a variety of conditions, covered by Medicare+Choice plans, and admitted to an SNF in 2002. Interventions Not applicable. Main Outcome Measures Item score distributions, corrected item-total correlations, factor correlations, internal consistency, and stage ceiling and floor effects for each hypothesized functional independence domain. Results With the exception of 2 items, the items within a domain had similar standard deviations and distributions of items were not highly skewed. Four factors accounted for 73.4% of the variance in functional independence. Corrected item-total correlations ranged from .58 to .80 for the ADL domain, from .23 to .71 for the mobility domain, and from .78 to .88 for the executive function domain. The correlation between bowel and bladder management items was .84. Cronbach α coefficients ranged from .76 for the mobility domain to .96 for the executive function domain. At admission, there were substantial floor effects for the sphincter management (34.4%) and mobility domains (43.1%) and ceiling effects for the executive function domain (26.7%). Conclusions With a few exceptions, the items proposed for each functional independence domain met the criteria for supporting the validity of the domains.

Validity and internal consistency of a whiplash-specific disability measure.

Cross-sectional study of patients with whiplash-associated disorders investigating the internal consistency, factor structure, response rates, and presence of floor and ceiling effects of the Whiplash Disability Questionnaire (WDQ). The aim of this study was to confirm the appropriateness of the proposed WDQ items. Whiplash injuries are a common cause of pain and disability after motor vehicle accidents. Neck disability questionnaires are often used in whiplash studies to assess neck pain but lack content validity for patients with whiplash-associated disorders. The newly developed WDQ measures functional limitations associated with whiplash injury and was designed after interviews with 83 patients with whiplash in a previous study. Researchers sought expert opinion on items of the WDQ, and items were then tested on a clinical whiplash population. Data were inspected to determine floor and ceiling effects, response rates, factor structure, and internal consistency. Packages of questionnaires were distributed to 55 clinicians, whose patients with whiplash completed and returned 101 questionnaires to researchers. No substantial floor or ceiling effects were identified on inspection of data. The overall floor effect was 12%, and the overall ceiling effect was 4%. Principal component analysis identified one broad factor that accounted for 65% of the variance in responses. Internal consistency was high; Cronbach's alpha = 0.96. Results of the study supported the retention of the 13 proposed items in a whiplash-specific disability questionnaire. Dependent on the results of further psychometric testing, the WDQ is likely to be an appropriate outcome measure for patients with whiplash.

Evaluating Changes in Sexual Functioning in Depressed Patients: Sensitivity to Change of the CSFQ

Accurately evaluating alterations in sexual functioning requires a validated instrument that measures clinically relevant change over time. One-hundred one depressed patients from 15 Spanish outpatient clinics completed the Changes in Sexual Functioning Questionnaire (CFSQ; Clayton, McGarvey, & Clavet, 1997) at baseline and after 6 months of treatment with fluoxetine, nefazodone, paroxetine, or venlafaxine. Sexual desire/interest showed a nearly substantial floor effect (30% of patients indicated the maximum score) for women in the nefazodone group at baseline and in the paroxetine group at final visit. The percentage of dimensions recording change was greater for women (80%) than for men (20%) in the nefazodone group (improving changes) and greater for men (40%) than for women (20%) in the paroxetine group (worsening changes). Highest effect sizes were found on sexual desire/frequency with improvement in women in the nefazodone group (SES = 0.49), and on orgasm/ejaculation with worsening in men in the paroxetine group (SES = -1.45). In conclusion, the CSFQ is sensitive to bidirectional changes and is appropriate for measuring sexual dysfunction.

Use of the short form health survey (SF-36) in patients with amyotrophic lateral sclerosis: tests of data quality, score reliability, response rate and scaling assumptions.

To evaluate response rate, data quality, score reliability and scaling assumptions of the 36 item Short Form Health Survey (SF-36) in a large scale pan European survey of amyotrophic lateral sclerosis (ALS) patients. A questionnaire based survey of patients diagnosed with ALS across 15 European countries. SAMPLE PATIENTS: presenting at neurological clinics for treatment of their condition were asked to partake in the survey. 948 patients have been recruited into the survey, from whom responses have been gained in 754 (79.5%). Scores on the eight dimensions of the SF-36 were found to manifest high internal consistency reliability. Items were, in most instances, found to be most highly correlated with their own (corrected) scale score than with other scale scores. However, on two dimensions (role-physical and role-emotional) there was high levels of missing data, together with substantial floor and ceiling effects. The two factor model (of underlying constructs of physical and emotional health) for the SF-36 suggested by the developers was not supported in this patient group. CONCLUSION The SF-36 appears to provide reliable information for this patient group, and for the most part there are high levels of item completeness and good spread of scores. This is not, however, true for the role functioning dimensions. Furthermore, the underlying two factor model for the SF-36 was not supported. The implications for measuring health status in this patient group are discussed.

Mixing and compositional stratification produced by natural convection: 2. Applications to the differentiation of basaltic and silicic magma chambers and komatiite lava flows

The petrogenesis of igneous rocks can be controlled significantly by the mixing of dissimilar magmas. Within the contexts of basaltic and silicic magma chambers and komatiite lava flows we identify circumstances in which the extent to which contrasting magmas are mixed by natural convection potentially controls their differentiation. To evaluate the amount of mixing in each context, we apply the experimental results from part 1 [Jellinek et al., this issue] of this study, in which we quantified the conditions under which fluids could be mixed by convection at large Rayleigh numbers (&gt; 1011). When our laboratory results are applied to basaltic magma chambers, we find that convection driven by compositionally buoyant magma released during floor crystallization or floor dissolution will produce partial to nearly complete mixing of the ascending fluid in chambers that are tens of meters to kilometers high, respectively. We also conclude that substantial floor melting (with extensive mixing) is expected only for basaltic chambers emplaced in the deep crust. During the turbulent flow of Archean komatiites, underlying sediments melted by forced convective heat transfer are predicted to have been mixed nearly completely into the overriding lavas. During the replenishment of silicic magma chambers by basaltic magmas we predict that the convection of buoyant silicic magma overrun by a spreading injection of denser basalt will cause little mixing. However, after emplacement, heat transfer from a basalt layer will gradually melt and mobilize its felsic floor, producing a small flux of buoyant felsic liquid that will be mixed extensively.

Performance of a new, HIV/AIDS-targeted quality of life (HAT-QoL) instrument in asymptomatic seropositive individuals.

To evaluate the psychometric performance of a new human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS)-targeted quality of life (QoL) instrument in asymptomatic HIV-seropositive individuals. 201 urban and rural, HIV-seropositive subjects were recruited to complete a 76-item pilot QoL measure developed using content provided in group process by seropositive individuals. Questionnaire responses from the full sample (n = 201) were used to identify dimensions and to reduce the number of items to 42. The responses to the retained items were then analysed for the asymptomatic subsample (n = 106). 9 multi-item dimensions were identified: overall function (OF), sexual function (SF), disclosure worries (DW), health worries (HW), financial worries (FW), HIV mastery (HM), life satisfaction (LS), medication concerns (MC) and provider trust (PT). The responses by asymptomatic subjects (74% male, 64% non-White and 63% homosexual/bisexual) revealed no substantial floor or ceiling effects, except for the PT dimension (where 44% were found to have scored the highest score). The internal consistency coefficients (Cronbach's alphas) were between 0.80 and 0.89 for six dimensions. The coefficients were lower for the SF (0.52), HM (0.67) and MC (0.48) dimensions. Construct validity assessments, using self-reported HIV disease-severity and sociodemographic variables, revealed some significant relationships (p < or = 0.05) for all dimensions except SF, MC and PT. The results suggested that five dimensions (OF, DW, HW, FW and LS) from the new instrument have good psychometric properties for asymptomatic HIV-seropositive individuals. These dimensions may be useful in the study of asymptomatic, seropositive individuals' QoL. Four dimensions (SF, HM, MC and PS) require additional refinement for this subpopulation.

History of Science and Technology: A Select Bibliography for Students by K. J. Rider (review)

The Chiba Museum of Science and Technology Eiju Matsumoto (bio) Since the early 1980s, Japanese regional governments have built more than thirty new science and technology museums. The emphasis has been on science education, in the manner of the Exploratorium in San Francisco, and several have been quite successful in pursuing that goal. Unique among these museums is the Chiba Museum of Science and Industry, which opened in 1994, and which in addition to its science center activities devotes substantial floor space to historical exhibits. In this review I shall describe these exhibits briefly, with attention to some of the special problems that Japanese museums face. I shall single out those exhibits that I feel are particularly effective, and offer comments where I think there could be improvement. 1 Chiba prefecture is best known to foreigners as the home of Narita Airport. In spite of its proximity to Tokyo, it has traditionally had a rural [End Page 102] economy. But in the 1950s the regional government began to reclaim land along the shoreline for industrial use and to encourage the establishment of modern industries. In the 1970s development was rapid, and today the prefecture ranks sixth nationally (out of fifty) in per capita income. These circumstances present a special challenge to the museum. It would like to provide a sense of the history of technology from the late nineteenth century to the twentieth, yet the history at hand is barely half a century old. To accomplish this it has relied on reproductions of early generators and a Siemens electric locomotive (built with the kind assistance of the Science Museum in London, the Deutsches Museum, and the Smithsonian Institution) and on photographs. In its treatment of Chiba industries the museum concentrates on three areas: electric power, petroleum, and steel, all modern industries that imply scientific knowledge and substantial capital. The exhibit area devoted to the electric power industry contains a large 1950s turbine rotor from the Chiba thermal power station No. 3 generator and a low-pressure turbine for a 175 kW generator, which is displayed at the entrance on the first floor because of its size (fig. 1). In addition, there is an exhibit of various windmills and a model of an 1897 Siemens electric car. As an introduction to the history of electricity, exhibit text describes the principles and historic significance of static electricity generated by friction and lightning, the voltaic cell, the Pixii generator, the first power station in New York, and the presence of two different power supply frequencies (50 Hz and 60 Hz) in Japan. [End Page 103] Click for larger view View full resolution Figure 1. Low-pressure turbine from the Chiba Thermal Power Station. (Photo courtesy of the Chiba Museum of Science and Industry.) For the petroleum industry, exhibits cover the discovery of petroleum, mass production and mass utilization of petroleum, and the first distillation tower in Chiba prefecture, as well as the ancient utilization of petroleum, Drake cable drilling, Aranbic distillation, continuous distillation, and modern oil refineries and petrochemical plants. These last are exhibited using small models. Iron and steel industry exhibits illustrate processes from the earliest times up to the introduction of the Bessemer converter in the nineteenth century. In addition, there is a 1/10 scale model of the No. 1 blast furnace at the Kawasaki Steel Corporation steel works. This was the first blast furnace installed in Chiba prefecture and had a capacity of 900 tons per day. Exhibit panels explain relics of ancient iron making, Bessemer converters, the Thomas basic converter, and western-style iron making in old Japan. 2 Another section of the museum is devoted to an “Invitation to Advanced Technology.” Within are four exhibition areas, titled “Techniques Supporting Advanced Technology: Realizing an Extreme Environment,” “Electronics: Progress of Electronic Technology,” “Advanced Materials: The Spread of Advanced Materials,” and “Biotechnology: The Growth of Biotechnology.” These exhibits are largely technical in nature, without significant historical content. On the first floor of the museum visitors come upon the “Area Open for Creativity,” where principles of scientific devices are demonstrated through hands-on exhibits. The exhibit techniques employed are diverse, with some borrowed from the Exploratorium and others created by the...