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PubMed1991

[Management of cochlear implants in children--methods and results].

Selection criteria, basic principles of auditory training, development of an auditory test battery for children and results of 15 children between 4 and 14 years are presented and discussed. To summarize, results range from acoustic attention to tones and sounds and recognition of environmental sounds to the use of supra-segmental and segmental features of speech. Some children are able to recognize words and phrases from a closed list. One of the children has postlingual deafness and has had also a very short duration of deafness before implantation. This child shows better results than the pre and perilingually deaf children. Because of the fact that the patient group is small and there are also many intervening variables like age, duration of deafness and use of two different test instruments, it is difficult to find a relationship between the results and all other variables. The auditory test battery for children, which consists of seven subtests, measuring acoustic orientation and auditory speech perception on different linguistic levels, is much more suitable for the evaluation of auditory performance for this age group than the auditory test battery for adults (Eisenwort and Burian 1988).

Adolescent↗
PubMed1992

Comparison of electroglottographic and acoustic analysis of pitch perturbation.

Pitch perturbation is a measure of the cycle-to-cycle variation in vocal fold vibration. Perturbation can be assessed by means of electroglottographic or acoustic signals. The purpose of this study was to determine if these two analysis techniques are equivalent measures. The Laryngograph, an electroglottograph, and the Visi-Pitch, an acoustic analyzer, were used to measure pitch perturbation in 80 dysphonic subjects. Both instruments use Koike's formula to calculate relative average perturbation. While intra-subject variability appeared erratic, statistical analysis of intersubject data indicated that the two instruments provided an equivalent measure of pitch perturbation.

Adult↗
PubMed1994

Resource utilization in home health care: results of a prospective study.

Resource utilization in home health care has become an issue of concern due to rising costs and recent initiatives to develop prospective payment systems for home health care. A number of issues remain unresolved for the development of prospective reimbursement in this sector, including the types of variables to be included as payment variables and appropriate measures of resource use. This study supplements previous work on home health case-mix by analyzing the factors affecting one aspect of resource use for skilled nursing visits--visit length--and explores the usefulness of several specially collected variables which are not routinely available in administrative records. A data collection instrument was developed with a focus group of skilled nurses, identifying a range of variables hypothesized to affect visit length. Five categories of variables were studied using multiple regression analysis: provider-related; patient's socio-economic status; patient's clinical status; patient's support services; and visit-specific. The final regression model identifies 9 variables which significantly affect visit time. Five of the 9 are visit-specific variables, a significant finding since these are not routinely collected. Case-mix systems which include visit time as a measure of resource use will need to investigate visit-specific variables, as this study indicates they could have the largest influence on visit time. Two other types of resources used in home health care, supplies and security drivers, were also investigated in less detail.

Boston↗
PubMed2002

Powered liposuction: an evaluation of currently available instrumentation.

BACKGROUND: Over the past several years, powered liposuction instruments have become available to the dermatologic surgeon. These instruments all move the cannula forward and backward 2-12 mm with rapidity. This motion simulates the standard human movement of the cannula and facilitates movement through the tissue. Powered liposuction may help to prevent surgeon fatigue and has recently been shown to aid in the efficacy of fat removal. OBJECTIVE: To compare and contrast currently available powered liposuction instruments, to obtain objective engineering data on the instruments, and to compare the instruments when used on actual liposuction cases. METHODS: Five currently available powered liposuction systems were evaluated by the author. Each instrument was used with a 3 mm dual side port cannula on patients undergoing tumescent liposuction. An independent engineering firm, who collected objective measurements such as weight, stroke force, temperature, and vibration measurements on the instruments, evaluated the units. Noise measurements were obtained. RESULTS: Each of the five systems showed advantages and disadvantages. Important issues were the size and weight of the units, as well as whether they were driven electrically or pneumatically. Stroke force is variable (range 9.5-30 pounds). The noise of the units ranged between 60 and 87 dB. Vibration measurements varied from instrument to instrument. Units produced a variable amount of heat ranging from 77 degrees F to 102 degrees F. Most instruments are autoclavable, and one system is disposable. Build quality and reliability varied with the instrument. CONCLUSION: Instruments for powered liposuction have emerged in the last 2 years, with each instrument having distinct advantages and disadvantages. This article reviews five currently available powered liposuction instruments and presents objective measurements as well as the author's experience using the instruments.

Abdomen↗
PubMed1999

An Italian national multicenter study for the definition of reference ranges for normal values of peripheral blood lymphocyte subsets in healthy adults.

BACKGROUND AND OBJECTIVE: Reference ranges are necessary in clinical chemistry and hematology to compare an observed value and to provide meaningful information. The aim of this multicenter study was the definition of reference ranges of the relative and absolute numbers of lymphocyte subsets by evaluating a large cohort of healthy adults and by using a standard protocol to reduce the variability in both sample preparation methodology and flow cytometer operation. Other aims of this study were the evaluation of the influence of sex, age, obesity, smoking, sport and some methodological variables on lymphocyte subsets and the comparison of differential white blood cell values obtained by flow cytometry and those obtained by hematology counters. DESIGN AND METHODS: Blood samples from 1311 healthy adults (blood donors and volunteers chosen according to the Italian law for donor selection) were analyzed to study, by flow cytometry, the immunophenotype of lymphocyte subsets and their distribution in terms of percentages and absolute values. Pre-analytical and analytical phases were performed according to the guidelines of the International Federation of Clinical Chemistry (IFCC) and the Italian Group of Cytometry (GIC). T cells were defined by the expression of CD3; T subpopulations by the coexpression of CD4 or CD8 or HLA-DR; B-lymphocytes were identified by the expression of CD19 while natural killer lymphocytes were identified by positivity of CD16 and/or CD56 without CD3. We calculated, for each laboratory and for all data collected, the frequency distribution percent values and absolute values of each lymphocyte subset. The influence of age, sex, smoking, obesity and sport was calculated by the t-test. The influence of some methodological variables was calculated by the t-test and multiple regression test. RESULTS: Fifty-three flow cytometry laboratories at different institutions in Italy participated in this study. Data was obtained from 1311 healthy adults aged from 18 to 70; 968 phenotype analyses (74%) were considered eligible for statistical analysis. Significant results were found as regards sex, smoking and some methodological variables (quantity of sample, washing procedures, brand of monoclonal antibodies and kind of instruments used). The comparison between hematology counters and cytometers showed no difference for any of the parameters considered. INTERPRETATION AND CONCLUSIONS: The large number of cases, the different kinds of laboratories and their distribution throughout the country make our sample representative of the Italian adult population. The standardization criteria of pre-analytical and analytical phases (the most important issues in evaluating reference values for an indicator) assured good reproducibility among laboratories so that the obtained reference ranges may be useful for interlaboratory comparison of results. Instruments and the brand of monoclonal antibodies may represent an inevitable cause of variability.

Blood Cells↗
PubMed2003

Identifying Mycobacterium species and strain typing using a microfluidic labchip instrument.

We developed schemes for rapid identification of Mycobacterium species and strain typing using a microfluidic labchip instrument. A 439-bp region of the gene that codes for the 65-kDa heat shock protein (hsp65), which has sequence polymorphisms specific for most mycobacterial species, was examined using PCR-restriction analysis (PRA). We performed PRA in duplicate, using 2 strains each of 12 species, and observed that fragment sizes (bp) determined automatically by the instrument were consistently smaller than the correct sizes for each of the species as determined by sequence analysis (mean variance, < 7 bp). Mycobacterium tuberculosis isolates were typed with the labchip instrument using mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing, which determines the number of copies of repeated units at 12 loci in the genome based on product size after PCR amplification. Seven strains with one to six repeat copies at each locus were examined. Sizes were smaller by a mean of 13.47 bp compared with correct sizes predicted by sequence analysis, but could be used to correctly identify all strains types. Isolates of Mycobacterium chelonae and Mycobacterium abscessus were typed using randomly amplified polymorphic DNA (RAPD) electrophoresis, and patterns obtained using the labchip instrument were compared with multilocus enzyme electrophoresis (MEE) types. Patterns were distinct and reproducible for all strains except those with closely related MEE types. The labchip instrument is a versatile alternative for sizing mycobacterial DNA fragments.

DNA, Bacterial↗
PubMed2004

Short-form activity measure for post-acute care.

OBJECTIVE: To develop a comprehensive set of short forms using item response theory (IRT) and item pooling procedures for the purpose of monitoring postacute care functional recovery. DESIGN: Prospective study. SETTING: Six postacute health care networks in the greater Boston area, including inpatient acute rehabilitation, transitional care units, home care, and outpatient services. PARTICIPANTS: A convenience sample of 485 adult volunteers who were currently receiving skilled rehabilitation services. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: We developed a set of 6 short forms across 3 activity domains from new items and items from existing postacute care instruments. RESULTS: Inpatient- and community-based short forms were developed for each of 3 activity domains: physical & movement, applied cognition, and personal care & instrumental. Items were selected for inclusion on the short forms to maximize content coverage and information value of items across the range of content and to minimize ceiling and floor effects. We were able to match the distribution of sample scores with very good item precision for 1 of the constructs (physical & movement); the other 2 domains (personal care & instrumental, applied cognition) were more challenging because of the variability in patient recovery and ceiling effects. CONCLUSIONS: ITR methods and item pooling procedures were valuable in developing paired sets of short-form instruments for inpatient and community rehabilitation that provided estimates of functioning along a common metric for use across postacute care settings.

Activities of Daily Living↗
PubMed1999

Repeated passive stretching: acute effect on the passive muscle moment and extensibility of short hamstrings.

OBJECTIVE: To examine the response of short hamstring muscles to repeated passive stretching. DESIGN: A repeated measures design. SETTING: A university laboratory for human movement analysis in a department of rehabilitation. SUBJECTS: Students (7 men, 10 women) from the Department of Human Movement Sciences. MAIN OUTCOME MEASURES: The lift force, range of motion, pelvic-femoral angle, first sensation of pain, and electromyogram of the hamstrings were measured. RESULTS: Comparison of the data of the test group (n = 17) after five successive passive stretch tests by means of an instrumental straight-leg raising test showed no significant change of the variables passive muscle stiffness and extensibility (p>.05). CONCLUSION: The acute effect of repeated passive stretching of short hamstring muscles is negligible. With an instrumental straight-leg raising test, the relevant muscle variables can be examined noninvasively.

Adult↗
PubMed2005

Random marginal agreement coefficients: rethinking the adjustment for chance when measuring agreement.

Agreement coefficients quantify how well a set of instruments agree in measuring some response on a population of interest. Many standard agreement coefficients (e.g. kappa for nominal, weighted kappa for ordinal, and the concordance correlation coefficient (CCC) for continuous responses) may indicate increasing agreement as the marginal distributions of the two instruments become more different even as the true cost of disagreement stays the same or increases. This problem has been described for the kappa coefficients; here we describe it for the CCC. We propose a solution for all types of responses in the form of random marginal agreement coefficients (RMACs), which use a different adjustment for chance than the standard agreement coefficients. Standard agreement coefficients model chance agreement using expected agreement between two independent random variables each distributed according to the marginal distribution of one of the instruments. RMACs adjust for chance by modeling two independent readings both from the mixture distribution that averages the two marginal distributions. In other words, both independent readings represent first a random choice of instrument, then a random draw from the marginal distribution of the chosen instrument. The advantage of the resulting RMAC is that differences between the two marginal distributions will not induce greater apparent agreement. As with the standard agreement coefficients, the RMACs do not require any assumptions about the bivariate distribution of the random variables associated with the two instruments. We describe the RMAC for nominal, ordinal and continuous data, and show through the delta method how to approximate the variances of some important special cases.

Data Interpretation, Statistical↗
PubMed1987

A data acquisition system for clinical research.

We developed a system for automatic collection and synchronization of multiple physiological variables during clinical investigations. Centered around an eight-track instrumentation tape recorder, the system solves several problems encountered in gathering this type of research data: (1) slowly changing variables are digitized and compressed onto a single track by recording them in one serial message, allowing for recording many more variables than there are tape tracks available; (2) simultaneous analog recording allows retention of original data for variables that may be processed subsequently by multiple schemes; (3) data acquisition is verified with both analog chart recording and numerical video display monitors; (4) off-line computer processing time is decreased at least twofold by using tape playback speeds faster than the recording speed; (5) cost is kept low by using an inexpensive 1/4-inch (0.64-cm) tape medium and dedicated microcomputers; and (6) the system is unobtrusive, portable, and easily reconfigured for different clinical studies. It proved to be reliable in a study of more than 80 patients undergoing cardiac surgery.

Computers↗
PubMedDate not supplied

Comparing the health status of VA and non-VA ambulatory patients: the veterans' health and medical outcomes studies.

The purpose of this study was to compare health status and disease profiles of ambulatory patients in specific Veterans Administration (VA) and civilian healthcare settings. A random sample of 2425 male veterans seeking care at 4 Boston-area VA outpatient clinics, who took part in the Veterans Health Study (VHS) in 1993-1995, were compared to 1318 male patients seeking civilian outpatient care in 3 major metropolitan areas covered in the Medical Outcomes Study (MOS) in 1986. The MOS sampled patients who had 1 of 5 conditions--hypertension, noninsulin-dependent diabetes, recent myocardial infarction, congestive heart failure, or depression. These 2 samples were age adjusted and compared in terms of the SF-36 Health Status/Quality of Life measures, and a list of 100 clinical variables (diagnostic, symptom, and medical event reports) collected with comparable instruments by a trained clinical observer. Individual odds ratios (VHS to MOS) were calculated for each measure and clinical variables. SF-36 measures of patient health in the VHS were lower than those in the MOS by more than one half of a standard deviation (SD) on 4 of 8 scales, by more than one quarter of a SD on the other 4, by 58% of a SD on the physical health summary scale, and by 37% of a SD on the mental health summary scale (P < .0001 in all cases). The median odds ratio was 2.2 among the SF-36 scales and 1.9 among clinical variables. Outpatients in the 4 VA clinics had more than twice the illness burden than did patients in the MOS. Current economic condition and service-connected disability explain most, if not all, of the differences. The differences were clinically and socially meaningful and would be consistent with substantially higher expected healthcare use.

Ambulatory Care Facilities↗
PubMedDate not supplied

Recent advances in mycotoxin determination in food and feed by hyphenated chromatographic techniques/mass spectrometry.

Mycotoxins are fungal toxins produced by molds, which occur universally in food and feed derivatives, and are produced under certain environmental conditions in the field before harvest, post-harvest, during storage, processing, and feeding. Mycotoxin contamination is one of the most relevant and worrisome problem concerning food and feed safety because it can cause a variety of toxic acute and chronic effects in human and animals. In this review we report the use of mass spectrometry in connection with chromatographic techniques for mycotoxin determination by considering separately the most diffuse class of mycotoxins: patulin, aflatoxins, ochratoxin A, zearalenone, trichothecenes, and fumonisins. Although the selectivity of mass spectrometry is unchallenged if compared to common GC and LC detection methods, accuracy, precision, and sensitivity may be extremely variable concerning the different mycotoxins, matrices, and instruments. The sensitivity issue may be a real problem in the case of LC/MS, where the response can be very different for the different ionization techniques (ESI, APCI, APPI). Therefore, when other detection methods (such as fluorescence or UV absorbance) can be used for the quantitative determination, LC/MS appears to be only an outstanding confirmatory technique. In contrast, when the toxins are not volatile and do not bear suitable chromophores or fluorophores, LC/MS appears to be the unique method to perform quantitative and qualitative analyses without requiring any derivatization procedure. The problem of exact quantitative determination in GC/MS and LC/MS methods is particularly important for mycotoxin determination in food, given the high variability of the matrices, and can be solved only by the use of isotopically labeled internal standards or by the use of ionization interfaces able to lower matrix effects and ion suppressions. When the problems linked to inconstant ionization and matrix effects will be solved, only MS detectors will allow to simplify more and more the sample preparation procedures and to avoid clean-up procedures, making feasible low-cost, high-throughput determination of mycotoxins in many different food matrices.

Animal Feed↗
PubMed1989

[Anglo-Saxon social research in mental health : tendencies, limits and impasses.].

In this critical review of English-language research on mental health, the authors identify the dimensions and variables taken into consideration in analyzing, on the one hand, social space and, on the other hand, the field of mental health. Three essential aspects of the body of research are analyzed : theoretical frames of reference ; methods and instruments ; and how links are made between social variables and mental-health problems. In a long conclusion, orientations of French-Quebec social research into mental health are compared to those of English research.

English Abstract↗
PubMedDate not supplied

Morale and perceived control in institutionalized elderly.

This study explored patterns of causal relationships among perception of situational control, health, socioeconomic status, functional dependency, length of stay, and morale in institutionalized elderly. Causal patterns in residents at two levels of care were contrasted. A total of 113 residents on intermediate and skilled care units chosen randomly from 4 urban proprietary nursing homes were studied. Variables were measured by means of an interview. Instruments included the Philadelphia Geriatric Center Morale Scale, Chang's Situational Control of Daily Activities Scale, and the Resident's Questionnaire. Path analysis was used with a causal model to estimate direct and indirect effects of the independent variables on morale. Important differences in the way the independent variables affected morale for residents on the two levels of care were reported. Perception of situational control proved to be a key variable, significantly related to the morale of residents on both levels of care, although the strength of the association was stronger for residents on skilled care. Functional dependency, health, and socioeconomic status had significant direct effects on the morale of residents on intermediate care but not those on skilled care.

Activities of Daily Living↗
PubMed2000

Tolerance of uncertainty of medical students and practicing physicians.

BACKGROUND: Tolerance of uncertainty is believed to be an important attribute of practicing physicians. This study attempts to (1) estimate how medical students perceive physicians' tolerance of uncertainty and (2) measure the tolerance of uncertainty of practicing physicians. RESEARCH DESIGN: Cross-sectional. SETTING AND SUBJECTS: Medical students (n = 113) and practicing physicians (n = 151) at the Faculty of Health Sciences, Ben-Gurion University, Israel. MEASURES: A self-administered, Hebrew version of an instrument developed in the United States. INDEPENDENT VARIABLES: Age, gender, seniority (year of study for students or years in practice for physicians), country of birth for students or of graduation for physicians, and physicians' specialty. DEPENDENT VARIABLES: Two dimensions, which were identified by factor analysis: reluctance to disclose uncertainty and stress from uncertainty. RESULTS: The estimates of physicians' stress from uncertainty by first-year students aged <22 years were higher than those by first-year students aged > or =22 years. There were no significant differences in the way junior and senior medical students perceived physicians' tolerance of uncertainty. Stress from uncertainty was higher in female physicians (P = 0.028) and in graduates of the former Soviet Union (P = 0.044) than among male physicians and Israeli graduates, respectively. Reluctance to disclose uncertainty was higher among graduates of the former Soviet Union (P = 0.003) and among psychiatrists (P = 0.021) than among Israeli graduates and other specialties, respectively. CONCLUSIONS: The reliability and factor structure of the instrument were replicated. The previously reported differences in tolerance of uncertainty between women and men and between local and foreign graduates were confirmed. Physicians' tolerance of uncertainty appeared to be higher than that attributed to them by students. The expected age-related differences in perception of clinical uncertainty were not detected between junior and senior medical students.

Adult↗
PubMed1994

Comparative efficacy of three indexes of left ventricular performance derived from pressure-volume loops in heart failure induced by tachypacing.

OBJECTIVES: The purpose of this study was to serially evaluate the response and variability of the end-systolic pressure-volume relation, the left ventricular end-diastolic volume-peak positive first derivative of left ventricular pressure (dP/dt) relation and the left ventricular end-diastolic volume-stroke work relation in the development of progressive left ventricular dysfunction. BACKGROUND: Evaluation of systolic performance of the failing left ventricle may be enhanced by using relatively load-insensitive measures of left ventricular performance. The end-systolic pressure-volume, left ventricular end-diastolic volume-peak positive dP/dt and left ventricular end-diastolic volume-stroke work relations adequately define left ventricular performance under multiple loading conditions, but efficacy has not been fully assessed in the failing heart, particularly in the intact circulation. METHODS: Fourteen dogs underwent instrumentation and rapid pacing to heart failure. Variably loaded pressure-volume beats were produced by inferior vena cava occlusion. The dogs were evaluated at baseline and at three progressively more severe levels of left ventricular dysfunction. RESULTS: There was a progressive increase in left ventricular volumes at end-diastole ([mean value +/- SE] 60 +/- 28 to 73 +/- 29 ml, p < 0.001) and end-systole (39 +/- 19 to 61 +/- 27 ml, p < 0.001) during the 3 weeks of rapid pacing and a progressive decline in peak positive dP/dt (1,631 +/- 410 to 993 +/- 222 mm Hg/s, p < 0.001) and ejection fraction (37 +/- 8% to 16 +/- 11%, p < 0.001). There was a corresponding decline in the slope of each of the three relations: for end-systolic pressure-volume, 6.3 +/- 2.2 to 2.8 +/- 0.7 (p < 0.05); for left ventricular end-diastolic volume-stroke work, 61.9 +/- 9.1 to 26.5 +/- 2.4 (p < 0.05); and for left ventricular end-diastolic volume-peak positive dP/dt, 47.1 +/- 13.6 to 20.31 +/- 6.8 (p < 0.05). There was also a corresponding increase in position volumes: for end-systolic pressure-volume, 33.6 +/- 3.9 to 61.2 +/- 6.6 ml (p < 0.05); for left ventricular end-diastolic volume-stroke work, 46.2 +/- 3.6 to 89.3 +/- 7.6 ml (p < 0.05); and for left ventricular end-diastolic volume-peak positive dP/dt, 29.1 +/- 19.1 to 68.6 +/- 25.9 ml (p < 0.05). The relative degree of change in each of the three relations was similar as more severe heart failure developed. The coefficients of variation for position were significantly less than the variation for slopes. The response of volume intercepts was heterogeneous. For left ventricular end-diastolic volume-stroke work, the intercept increased as ventricular performance decreased. The intercept of the end-systolic pressure-volume relation was significantly more variable than the left ventricular end-diastolic volume-stroke work relation and did not change with progressive heart failure. The intercept for left ventricular end-diastolic volume-peak positive dP/dt was highly variable and showed no consistent changes as left ventricular function declined. CONCLUSIONS: All three relations consistently describe changes in left ventricular performance brought about by tachypacing. Evolution of left ventricular dysfunction causes a decline in slope and a rightward shift of these relations. The position of the relation is the most sensitive and least variable indicator of left ventricular systolic performance.

Animals↗
PubMed1994

Accuracy of infrared ear thermometry and other temperature methods in adults.

OBJECTIVE: To compare the accuracy of infrared ear-based temperature measurement in relation to thermometer, ear position, and other temperature methods, with pulmonary artery temperature as the reference. METHODS: Ear-based temperature measurements were made with four infrared thermometers, three in the core mode and two in the unadjusted mode, each with tug and no-tug techniques. Pulmonary artery, bladder (n = 21), and axillary temperatures were read after each ear-based measurement and oral temperature was measured once when possible (n = 32). Subjects consisted of a convenience sample of 50 patients with pulmonary artery catheters who were in adult critical care units of a university teaching hospital. RESULTS: Ear-based measurements correlated well with pulmonary artery temperature (r = .87 to .91), although closeness of agreement differed among thermometer-mode combinations (mean offsets = -0.7 to 0.5 degree C) and had moderately high variability between subjects (SD = +/- 0.5 degree C) with all instruments. Use of an ear tug either made no difference or resulted in slightly lower readings. Bladder temperature was nearly identical to pulmonary artery temperature values (r = .99, offset = 0.0 +/- 0.2 degree C). Oral readings were slightly lower (r = .78, offset = -0.2 degree C) and axillary readings much more so (r = .80 to .82, offset = -0.7 degree C); both were highly variable (SD = +/- 0.6 degree C) and affected by external factors. CONCLUSIONS: Infrared ear thermometry is useful for clinical temperature measurement as long as moderately high variability between patients is acceptable. Readings differ among thermometers, although several instruments provide values close to pulmonary artery temperature in adults. Readings are not higher with an ear tug. Bladder temperature substitutes well for pulmonary artery temperature, whereas oral and axillary values may be influenced by external factors in the critical care setting.

Adult↗
PubMed2005

Short-term variability of overcast brightness.

Overcasts seen from below seldom are uniform, unchanging cloud shields, yet little is known about their short-term photometric variability (periods < or = 2 h). Visible-wavelength spectra of daytime and twilight overcast skies measured at 30-s intervals reveal unexpected temporal variability in horizontal illuminance E(v) and zenith luminance L(v). Fourier analysis of these time series shows peak fluctuations at periods of 2-40 min. Factors such as cloud type and optical depth, presence of fog or snow, and instrument field of view can affect overcast brightness variability. Surprisingly, under some circumstances overcast twilight E(v) exceeds clear-sky E(v) at the same Sun elevation.

Journal Article↗