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PubMed1998

Tests of data quality, scaling assumptions, and reliability of the SF-36 in eleven countries: results from the IQOLA Project. International Quality of Life Assessment.

Data from general population samples in 11 countries (n = 1483 to 9151) were used to assess data quality and test the assumptions underlying the construction and scoring of multi-item scales from the SF-36 Health Survey. Across all countries, the rate of item-level missing data generally was low, although slightly higher for items printed in the grid format. In each country, item means generally were clustered as hypothesized within scales. Correlations between items and hypothesized scales were greater than 0.40 with one exception, supporting item internal consistency. Items generally correlated significantly higher with their own scale than with competing scales, supporting item discriminant validity. Scales could be constructed for 93-100% of respondents. Internal consistency reliability of the eight SF-36 scales was above 0.70 for all scales, with two exceptions. Floor effects were low for all except the two role functioning scales; ceiling effects were high for both role functioning scales and also were noteworthy for the Physical Functioning, Bodily Pain, and Social Functioning scales in some countries. These results support the construction and scoring of the SF-36 translations in these 11 countries using the method of summated ratings.

Cross-Cultural Comparison↗

PubMed1999

The Mental Adjustment to Cancer (MAC) scale: replication and refinement in 632 breast cancer patients.

BACKGROUND: Assessment of adjustment of patients in cancer treatment trials is becoming more common and increasingly regarded as a useful outcome measure. The widely used Mental Adjustment to Cancer (MAC) Scale was designed to measure Fighting Spirit (FS), Anxious Preoccupation (AP), Helpless-hopelessness (HH) and Fatalism. METHODS: Questionnaire responses from 632 breast cancer patients were randomly divided into two groups, one for exploratory analyses and possible scale refinement, and the other for validation purposes. RESULTS: Estimates of reliability (Cronbach's alpha) were satisfactory for two scales, FS (alpha = 0.85) and HH (alpha = 0.81), but lower for AP (alpha = 0.65) and Fatalism (alpha = 0.64). Exploratory factor analysis suggested that the MAC Scale might be measuring six independent constructs including two related to Fighting Spirit (Positive Orientation to the Illness, Minimizing the Illness), two related to Fatalism (Fatalism-revised, Loss of Control), a construct we have named Angst, and an unchanged HH construct. Scales developed to measure these constructs were satisfactorily replicated in confirmatory analyses but some reliabilities were lower than desirable. The general structure of the MAC Scale remained little changed despite the division of two scales and the suggested removal of six items. The refined scales correlated with the Hospital Anxiety and Depression scale and the Medical Coping Modes Questionnaire, indicating good concurrent validity. CONCLUSIONS: While reasonable reliability of the original scales persists through analyses of the MAC Scale, the original factor structure could not be reproduced. Six refined constructs with strong construct validity were identified within the overall domain of mental adjustment to cancer.

Adaptation, Psychological↗

PubMedDate not supplied

Similarity search profiling reveals effects of fingerprint scaling in virtual screening.

Fingerprint scaling is a method to increase the performance of similarity search calculations. It is based on the detection of bit patterns in keyed fingerprints that are signatures of specific compound classes. Application of scaling factors to consensus bits that are mostly set on emphasizes signature bit patterns during similarity searching and has been shown to improve search results for different fingerprints. Similarity search profiling has recently been introduced as a method to analyze similarity search calculations. Profiles separately monitor correctly identified hits and other detected database compounds as a function of similarity threshold values and make it possible to estimate whether virtual screening calculations can be successful or to evaluate why they fail. This similarity search profile technique has been applied here to study fingerprint scaling in detail and better understand effects that are responsible for its performance. In particular, we have focused on the qualitative and quantitative analysis of similarity search profiles under scaling conditions. Therefore, we have carried out systematic similarity search calculations for 23 biological activity classes under scaling conditions over a wide range of scaling factors in a compound database containing approximately 1.3 million molecules and monitored these calculations in similarity search profiles. Analysis of these profiles confirmed increases in hit rates as a consequence of scaling and revealed that scaling influences similarity search calculations in different ways. Based on scaled similarity search profiles, compound sets could be divided into different categories. In a number of cases, increases in search performance under scaling conditions were due to a more significant relative increase in correctly identified hits than detected false-positives. This was also consistent with the finding that preferred similarity threshold values increased due to fingerprint scaling, which was well illustrated by similarity search profiling.

Journal Article↗

PubMed2003

Using item response theory to calibrate the Headache Impact Test (HIT) to the metric of traditional headache scales.

BACKGROUND: Item response theory (IRT) scoring of health status questionnaires offers many advantages. However, to ensure 'backwards comparability' and to facilitate interpretations of results, we need the ability to express the IRT score in the metrics of the traditional scales. OBJECTIVES: To develop procedures to calibrate IRT-based scores on the Headache Impact Test (HIT) into the metrics of the traditional headache scales. To assess the degree to which the calibrated HIT scores agree with the observed traditional scores and lead to the same conclusions in group comparisons. METHODS: We used telephone interview data (n = 1016) and Internet data (n = 1103) from general population surveys of recent headache sufferers. Analyses were conducted in four steps: (1) develop IRT models for all items, (2) for each IRT score level, calculate the expected score on each of the traditional scales (calibration), (3) adjust this calibrated score for measurement error in the IRT score, (4) for each of the traditional scales, assess agreement between calibrated HIT scores and observed scores using intraclass correlation (ICC) and evaluate the agreement of mean scores and the relative validity (RV) in discriminating among groups differing in migraine diagnosis, headache severity, and change in impact over time. RESULTS: For the traditional categorical questionnaire items (the Migraine Specific Questionnaire (MSQ) and the Headache Disability Inventory (HDI)) the calibrated HIT agreed with the observed traditional scores: ICC's were between 0.80 and 0.94. In RV analyses the maximum mean difference between the observed and expected scores was 1.7 points on a 0-100 scale for comparisons at one point in time. Analyses of change over time and analyses calibrating scores from the fixed-form HIT-6 to the metric of other questionnaires were also satisfactory although less precise. Analysis of non-standard questionnaire items (e.g. On how many days in the past 3 months did you have a headache, from the HIMQ and the MIDAS) required special IRT models. Agreement was less good: ICC's were between 0.56 and 0.61 and the maximum mean differences were 2.9 (on a 0-270 scale) and 3.8 (on a 0-450 scale) in RV analyses at one point in time. The ability of the calibrated scale scores to discriminate between groups was at least as good as the ability of the observed sum scales and often remarkably better. CONCLUSION: The theoretical advantage of IRT models in scale calibration is supported by our results. This approach to achieving comparability of new and widely-used scales and accelerating the accumulation of interpretation guidelines based on previous work warrant testing for measures of other generic and disease-specific concepts.

Adolescent↗

PubMed1999

Infants' and adults' perception of scale structure.

Adults and 9-month-old infants were required to detect mistuned tones in multitone sequences. When 7-tone versions of a common nursery tune were generated from the Western major scale (unequal scale steps) or from an alternative scale (equal steps), infants detected the mistuned tones more accurately in the unequal-step context than in the equal-step context (Experiment 1). Infants and adults were subsequently tested with 1 of 3 ascending-descending scales (15 tones): (a) a potentially familiar scale (major) with unequal steps, (b) an unfamiliar scale with unequal steps, and (c) an unfamiliar scale with equal steps. Infants detected mistuned tones only in the scales with unequal steps (Experiment 2). Adults performed better on the familiar (major) unequal-step scale and equally poorly on both unfamiliar scales (Experiments 3 and 4). These findings are indicative of an inherent processing bias favoring unequal-step scales.

Age Factors↗

PubMed2001

Fat phobia scale revisited: the short form.

OBJECTIVE: To develop a shortened form of the original 50-item fat phobia scale. METHOD: The first factor from the original fat phobia scale-undisciplined, inactive and unappealing-was identified as a potential short form of the scale. A new sample of 255 people completed the original 50-item scale. The reliability of a shortened 14-item version of the scale was tested and compared to that of the full scale using both the new sample and the original sample of 1135 study participants. RESULTS: The fat phobia scale-short form demonstrated excellent reliability in both samples and was strongly correlated with the 50-item scale. Mean and 90th percentile scores are given for both the long and short versions of the scale. CONCLUSION: The shortened fat phobia scale is expected to increase the utility of the measure in a diverse array of research and clinical settings. Future research should focus on developing scale norms for the general population and conducting research on fat phobia in males and among different ethnic groups.

Adolescent↗

PubMed1999

Quantitative estimation and recommendations for supplementation of protein lost through scaling in exfoliative dermatitis.

BACKGROUND: Exfoliative dermatitis (ED) can result in protein loss due to scaling causing a negative nitrogen balance. Freedberg and Baden (J Invest Dermatol 1962; 38: 277-284) estimated the amount of scale lost in ED by collecting it in an occlusive suit. Subsequently, the nitrogen content was determined by the Kjeldahl method. The exact amount of protein supplementation in ED, dependent on scale loss, is not well established. As occlusion and hyperthermia caused by the suit can inhibit scaling, the objectives of the present study were to design an alternative method to measure the amount of scale lost, to estimate the protein content of the scale, and to propose suitable recommendations for protein supplementation. METHODS: In 40 patients with ED, the total protein content lost through scaling per day (P) was determined by the following equation: P = TxIxYxX/25x10(4) g, where T is the total body surface area in square meters, I is the percentage area involved in scaling, estimated using computer-aided design (CAD graph), Y is the amount of scale lost per unit area (0.0025 m2) in milligrams, and X is the quantity of protein present in 1 g of scale in milligrams estimated by a spectrophotometer. RESULTS: It was observed that patients with ED secondary to drug reactions, eczema, and psoriasis lost 7.2, 9.6, and 22.6 g of scale with a protein content of 4.2, 5.6, and 12.8 g respectively. The difference in the amount of protein lost in ED secondary to drug reactions and eczema was not statistically significant; however, the protein lost in psoriasis was significant (p < 0.01 to p < 0.05). CONCLUSIONS: ED may increase the daily protein loss by approximately 25-30% in psoriasis and 10-15% in other causes. Standard treatment for ED and protein supplementation based on our recommendations can minimize the adverse effects of a negative nitrogen balance.

Albumins↗

PubMed2001

Lower extremity prosthetic mobility: a comparison of 3 self-report scales.

OBJECTIVE: To assess and compare the reliability and validity of the Houghton Scale, the Prosthetic Profile of the Amputee Locomotor Capabilities Index (PPA-LCI), and the Prosthetic Evaluation Questionnaire (PEQ) mobility subscale, 3 disease-specific self-report measures of functional mobility for lower extremity prosthetic mobility. DESIGN: Four-week test-retest: 1 sample for reliability analyses, 1 sample for validity analyses. SETTING: University-affiliated outpatient amputee clinic, in Ontario, Canada. PARTICIPANTS: Two outpatient amputee samples (sample 1 [n = 55], for reliability analysis; sample 2 [n = 329], for validity analysis). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Test-retest of reliability and convergent validity of the 3 scales. Convergent validity and discriminative ability were also assessed after setting a priori hypotheses for 2 scales of walking performance, balance confidence, and other indicators of ambulatory ability. RESULTS: The reliability of the PPA-LCI (intraclass correlation coefficient [ICC] = .88) was slightly higher than the Houghton Scale (ICC = .85) and the PEQ mobility subscale (ICC = .77). The PPA-LCI was prone to high ceiling effects (40%) that would limit its ability to detect improvement. Evidence for convergent validity, when compared with the 2-Minute Walk Test, Timed Up and Go, and the Activity-Specific Balance Confidence Scale, was supported as hypothesized in all the scales. Each of the scales was able to discriminate between different groups for amputation cause, walking distance, mobility device use, and automatism, with each having varying strength related to relative precision. The Houghton Scale was the only scale able to distinguish between amputation levels. CONCLUSIONS: Reliability and validity of all the scales are acceptable for group level comparison. None of the scales had clearly superior psychometric properties compared with the others. Further research is required to assess responsiveness.

Artificial Limbs↗

PubMed1997

Construction of scales for the Center for Marital and Sexual Health (CMASH) Sexual Functioning Questionnaire.

The objective of this study was to identify a set of scales for summarizing the results of the Center for Marital and Sexual Health Sexual Functioning Questionnaire (CMASH SFQ). Scales for this instrument were constructed using patients' responses to the CMASH SFQ in a recent clinical trial of prostaglandin E1 (PGE1, alprostadil), an injectable vasodilator used to treat erectile dysfunction. A set of items was identified as a scale if they met predetermined standards of internal consistency, discriminant validity, and convergent validity. The reproducibility of the scales was then evaluated, and the extent to which the scales reliably measured change in treatment-related quality of life was assessed. Reliable and responsive scales for four domains related to sexual functioning were identified. Items in these scales were generally internally consistent; items in the scales and the scores for the scales generally satisfied criteria of discriminant validity; and the scales generally satisfied the standard for convergent validity. Evaluating patients' responses to the CMASH SFQ with scores for four reliable and responsive scales allows easier summarization of patients' sexual functioning and increases the statistical power of evaluations of the effects of interventions designed to improve sexual functioning.

Adult↗

PubMed2004

Development and validation of an Arabic rheumatoid hand disability scale.

PURPOSE: To develop a rheumatoid hand disability scale in the Arabic language adapted for local sociocultural specificities and to test its psychometric properties. METHODS: The choice of hand activities was based on several published indices. The selected items were translated by the forward and backward translation procedures, several modifications were made, and after some questions were added, a provisional scale was obtained. In- and outpatients with rheumatoid arthritis (RA) according to the ACR criteria were chosen to answer the provisional scale and to assess the final scale. Impairment outcome measures (pain as measured on a visual analogue scale, morning stiffness, hand swelling, tenderness), and assessment of disability (on Lee's and Revel's functional indices) were also recorded. The intraclass correlation coefficient and the Bland and Altman methods were used to assess reliability. Construct (convergent and divergent) validity was investigated with use of Spearman's rank correlation, and a factor analysis was performed. RESULTS: The provisional scale had 21 questions. The adaptation process left 10 questions about hand activity, with four levels of answers. Eighty patients with RA were recruited for the validation of the final scale. The intra- and interrater reliabilities of the scale were 0.96 and 0.94, respectively. Analysis by the Bland and Altman method showed no systematic trend. The scale had good construct validity, with expected convergence with Lee's functional index (r(s)=0.79) and Revel's functional index (r(s)=0.81) and divergence with age (r(s)=0.05), morning stiffness (r(s)=0.40), pain (r(s)=0.32), and tenderness (r(s)= -0.48). The factorial structure of the scale was satisfying, with two factors explaining 73% of the variance. CONCLUSION: We developed an Arabic index that assesses hand disability due to RA and suits Tunisian people. Further studies are needed to confirm the validity of the scale in other Arabic countries.

Adolescent↗

PubMed2004

A simple post hoc transformation that improves the metric properties of the BBB scale for rats with moderate to severe spinal cord injury.

The Basso, Beattie, Bresnahan (BBB) open field locomotor scale is a popular measure of functional recovery following spinal cord injury (SCI). To examine the metric properties of the scale, we performed detailed analyses of BBB scores from 643 rats with moderate and severe SCI (12.5, 25, or 50 mm MASCIS) from two different laboratories. The analyses revealed that the BBB scale is ordinal in the most frequently used portion of the scale. Higher scores (14 and greater) were not frequently assigned in the dataset as animals with mild injuries were not sampled, making the ordinal nature of the upper end of the scale difficult to assess. The rare scores assigned in this range disproportionately increased variance. Under these conditions collapsing scores above 14 into one category increased effect size. Analysis of the lower region of the scale revealed that some scores (2 and 3) were rarely assigned, implying a discontinuity in the scale. The discontinuous nature of the lower portion of the scale presents a problem for both parametric and nonparametric statistical analyses. Pooling scores 2/3/4 eliminated the gap, enhancing the metric properties of the scale. Under the injury conditions evaluated, the transformation helped assure that the data were continuous and ordered. Further, interval durations were comparable across the entire range of the transformed scale, allowing application of parametric statistical techniques. The transformation should be applied in a post hoc fashion to reduce variability and increase power in cases where few scores fall in upper portion of the scale.

Animals↗

PubMed1986

Development, reliability, and validity of a dissociation scale.

Dissociation is a lack of the normal integration of thoughts, feelings, and experiences into the stream of consciousness and memory. Dissociation occurs to some degree in normal individuals and is thought to be more prevalent in persons with major mental illnesses. The Dissociative Experiences Scale (DES) has been developed to offer a means of reliably measuring dissociation in normal and clinical populations. Scale items were developed using clinical data and interviews, scales involving memory loss, and consultations with experts in dissociation. Pilot testing was performed to refine the wording and format of the scale. The scale is a 28-item self-report questionnaire. Subjects were asked to make slashes on 100-mm lines to indicate where they fall on a continuum for each question. In addition, demographic information (age, sex, occupation, and level of education) was collected so that the connection between these variables and scale scores could be examined. The mean of all item scores ranges from 0 to 100 and is called the DES score. The scale was administered to between 10 and 39 subjects in each of the following populations: normal adults, late adolescent college students, and persons suffering from alcoholism, agoraphobia, phobic-anxious disorders, posttraumatic stress disorder, schizophrenia, and multiple personality disorder. Reliability testing of the scale showed that the scale had good test-retest and good split-half reliability. Item-scale score correlations were all significant, indicating good internal consistency and construct validity. A Kruskal-Wallis test and post hoc comparisons of the scores of the eight populations provided evidence of the scale's criterion-referenced validity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed2000

Detection of macro-ecological patterns in South American hummingbirds is affected by spatial scale.

Scale is widely recognized as a fundamental conceptual problem in biology, but the question of whether species-richness patterns vary with scale is often ignored in macro-ecological analyses, despite the increasing application of such data in international conservation programmes. We tested for scaling effects in species-richness gradients with spatially scaled data for 241 species of South American hummingbirds (Trochilidae). Analyses revealed that scale matters above and beyond the effect of quadrat area. Species richness was positively correlated with latitude and topographical relief at ten different spatial scales spanning two orders of magnitude (ca. 12,300 to ca. 1,225,000 km2). Surprisingly, when the influence of topography was removed, the conditional variation in species richness explained by latitude fell precipitously to insignificance at coarser spatial scales. The perception of macro-ecological pattern thus depends directly upon the scale of analysis. Although our results suggest there is no single correct scale for macro-ecological analyses, the averaging effect of quadrat sampling at coarser geographical scales obscures the fine structure of species-richness gradients and localized richness peaks, decreasing the power of statistical tests to discriminate the causal agents of regional richness gradients. Ideally, the scale of analysis should be varied systematically to provide the optimal resolution of macro-ecological pattern.

Animals↗

PubMed2000

Anomalous scaling in the anisotropic sectors of the kraichnan model of passive scalar advection

Kraichnan's model of passive scalar advection in which the driving (Gaussian) velocity field has fast temporal decorrelation is studied as a case model for understanding the anomalous scaling behavior in the anisotropic sectors of turbulent fields. We show here that the solutions of the Kraichnan equation for the n-order correlation functions foliate into sectors that are classified by the irreducible representations of the SO(d) symmetry group. We find a discrete spectrum of universal anomalous exponents, with a different exponent characterizing the scaling behavior in every sector. Generically the correlation functions and structure functions appear as sums over all these contributions, with nonuniversal amplitudes that are determined by the anisotropic boundary conditions. The isotropic sector is always characterized by the smallest exponent, and therefore for sufficiently small scales local isotropy is always restored. The calculation of the anomalous exponents is done in two complementary ways. In the first they are obtained from the analysis of the correlation functions of gradient fields. The theory of these functions involves the control of logarithmic divergences that translate into anomalous scaling with the ratio of the inner and the outer scales appearing in the final result. In the second method we compute the exponents from the zero modes of the Kraichnan equation for the correlation functions of the scalar field itself. In this case the renormalization scale is the outer scale. The two approaches lead to the same scaling exponents for the same statistical objects, illuminating the relative role of the outer and inner scales as renormalization scales. In addition we derive exact fusion rules, which govern the small scale asymptotics of the correlation functions in all the sectors of the symmetry group and in all dimensions.

Journal Article↗

PubMed2006

Nearly incompressible fluids: hydrodynamics and large scale inhomogeneity.

A system of hydrodynamic equations in the presence of large-scale inhomogeneities for a high plasma beta solar wind is derived. The theory is derived under the assumption of low turbulent Mach number and is developed for the flows where the usual incompressible description is not satisfactory and a full compressible treatment is too complex for any analytical studies. When the effects of compressibility are incorporated only weakly, a new description, referred to as "nearly incompressible hydrodynamics," is obtained. The nearly incompressible theory, was originally applied to homogeneous flows. However, large-scale gradients in density, pressure, temperature, etc., are typical in the solar wind and it was unclear how inhomogeneities would affect the usual incompressible and nearly incompressible descriptions. In the homogeneous case, the lowest order expansion of the fully compressible equations leads to the usual incompressible equations, followed at higher orders by the nearly incompressible equations, as introduced by Zank and Matthaeus. With this work we show that the inclusion of large-scale inhomogeneities (in this case time-independent and radially symmetric background solar wind) modifies the leading-order incompressible description of solar wind flow. We find, for example, that the divergence of velocity fluctuations is nonsolenoidal and that density fluctuations can be described to leading order as a passive scalar. Locally (for small lengthscales), this system of equations converges to the usual incompressible equations and we therefore use the term "locally incompressible" to describe the equations. This term should be distinguished from the term "nearly incompressible," which is reserved for higher-order corrections. Furthermore, we find that density fluctuations scale with Mach number linearly, in contrast to the original homogeneous nearly incompressible theory, in which density fluctuations scale with the square of Mach number. Inhomogeneous nearly incompressible equations for higher order fluctuation components are derived and it is shown that they converge to the usual homogeneous nearly incompressible equations in the limit of no large-scale background. We use a time and length scale separation procedure to obtain wave equations for the acoustic pressure and velocity perturbations propagating on fast-time-short-wavelength scales. On these scales, the pseudosound relation, used to relate density and pressure fluctuations, is also obtained. In both cases, the speed of propagation (sound speed) depends on background variables and therefore varies spatially. For slow-time scales, a simple pseudosound relation cannot be obtained and density and pressure fluctuations are implicitly related through a relation which can be solved only numerically. Subject to some simplifications, a generalized inhomogeneous pseudosound relation is derived. With this paper, we extend the theory of nearly incompressible hydrodynamics to flows, including the solar wind, which include large-scale inhomogeneities (in this case radially symmetric and in equilibrium).

Journal Article↗

PubMed2004

Validation of pressure ulcer risk assessment scales: a critique.

AIM: The aim of this paper is to present critical analysis of the validation methods of pressure ulcer risk assessment scales. BACKGROUND: The validation of pressure ulcer risk assessment scales remains a topic of considerable debate and uncertainty. The Braden scale and Norton scale are the most frequently used. Sensitivity and specificity are the recommended and most commonly used epidemiological tools to evaluate the validity of those risk assessment scales. DISCUSSION: The use of preventive measures influences both the sensitivity and specificity of the scales. Analysis of published studies on risk assessment scales reveals that, although some patients received preventive measures and others did not, this was not taken into account. Consequently, generalization of those results is not possible. Some possible alternative designs for studying the validity of risk assessment scales are discussed. CONCLUSIONS: Currently available risk assessment scales are of only limited value, and there use will result in many patients being falsely identified as at risk or not at risk. Sensitivity and specificity criteria are not the most appropriate tools to validate risk assessment scales. A risk assessment scale should be evaluated in combination with the preventive measures used.

Humans↗

PubMed2005

Home Healthcare Nurses' Job Satisfaction Scale: refinement and psychometric testing.

AIMS: This paper describes a study to further develop and test the psychometric properties of the Home Healthcare Nurses' Job Satisfaction Scale, including reliability and construct and criterion validity. BACKGROUND: Numerous scales have been developed to measure nurses' job satisfaction. Only one, the Home Healthcare Nurses' Job Satisfaction Scale, has been designed specifically to measure job satisfaction of home healthcare nurses. The Home Healthcare Nurses' Job Satisfaction Scale is based on a theoretical model that integrates the findings of empirical research related to job satisfaction. METHODS: A convenience sample of 340 home healthcare nurses completed the Home Healthcare Nurses' Job Satisfaction Scale and the Mueller and McCloskey Satisfaction Scale, which was used to test criterion validity. Factor analysis was used for testing and refinement of the theory-based assignment of items to constructs. Reliability was assessed by Cronbach's alpha internal consistency reliability coefficients. The data were collected in 2003. RESULTS: Nine factors contributing to home healthcare nurses' job satisfaction emerged from the factor analysis and were strongly supported by the underlying theory. Factor loadings were all above 0.4. Cronbach's alpha coefficients for each of the nine subscales ranged from 0.64 to 0.83; the alpha for the global scale was 0.89. The correlations between the Home Healthcare Nurses' Job Satisfaction Scale and Mueller and McCloskey Satisfaction Scale was 0.79, indicating good criterion-related validity. CONCLUSIONS: The Home Healthcare Nurses' Job Satisfaction Scale has potential as a reliable and valid scale for measurement of job satisfaction of home healthcare nurses.

Adult↗

PubMed2007

Scale dependence of immigration rates: models, metrics and data.

1. We examine the relationship between immigration rate and patch area for different types of movement behaviours and detection modes. Theoretical models suggest that the scale dependence of the immigration rate per unit area (I/A) can be described by a power model I/A = i*Area(zeta), where zeta describes the strength of the scale dependence. 2. Three types of scaling were identified. Area scaling (zeta = 0) is expected for passively dispersed organisms that have the same probability of landing anywhere in the patch. Perimeter scaling (-0.30 > zeta > -0.45) is expected when patches are detected from a very short distance and immigrants arrive over the patch boundary, whereas diameter scaling (zeta = -0.5) is expected if patches are detected from a long distance or if search is approximately linear. 3. A meta-analysis of published empirical studies of the scale dependence of immigration rates in terrestrial insects suggests that butterflies show diameter scaling, aphids show area scaling, and the scaling of beetle immigration is highly variable. We conclude that the scaling of immigration rates in many cases can be predicted from search behaviour and the mode of patch detection.

Animals↗