Frequency Response Scales Research Articles

An Exploratory Study of Alternative Time Frames and Descriptors for EQ-5D-5L in Obstructive Airway Diseases Using Mixed Methods

ObjectivesEQ-5D-5L with its recall time of “today” may limit its ability to capture episodic symptoms and exacerbations in chronic obstructive airway diseases (OAD). We examined whether longer time frames and changing the intensity response scales to frequency scales could improve the measurement properties of EQ-5D-5L. MethodsWe used a mixed-method design starting with in-depth interviews with 20 patients and clinicians to elicit preferred time frames using concept elicitation techniques and content analyses. We then administered the top 4 preferred variants using 1- and 4-weeks’ time frames with the original intensity or an alternative frequency response scale alongside EQ-5D-5L and St George Respiratory Questionnaire to OAD patients during 2 different visits. We compared the ceiling effects and construct validity by testing a priori hypotheses in relation to St George Respiratory Questionnaire and clinical outcomes via correlation and receiver operating characteristic (ROC) analyses, respectively. Follow-up patients were categorized into “better,” “stable,” and “worse” groups to assess reliability using intraclass correlation coefficient (ICC) or Cohen’s Kappa (k) and responsiveness using ROC analysis. ResultsA total of 184 patients (mean [SD] age: 54[18]; female: 37.0%) completed baseline assessments. A total of 120 patients also completed follow-up assessments (mean [SD] interval: 2.8 [1.7] months). The ceilings were lower in the variants compared with EQ-5D-5L (P < .001). Reliability of the variants were comparable to or higher than EQ-5D-5L. The c-statistic values derived from ROC analyses of the variants were consistently higher than EQ-5D-5L. ConclusionsUse of longer time frames with the original intensity or the frequency response scales may improve EQ-5D-5L’s psychometric properties in OAD patients.

Quantitative Frequency Security Assessment of Modern Power System Considering All the Three Indicators in Primary Frequency Response

The primary frequency response scale is deteriorating in the modern power system due to the high penetration of different power devices. Frequency security assessments are essential for the operation or stability-checking of the power system. Firstly, this paper establishes the Unified Transfer Function Structure (UTFS) of power systems with highly penetrated wind turbines. Based on the UTFS, this paper analyzes the three indicators of the primary frequency responses. Secondly, to better assess the security of the frequency, the secondary frequency drop (SFD) is avoided, with the frequency response parameters of the wind turbines calculated. Moreover, considering all three indicators of the primary frequency response, this paper proposes a frequency security margin index (FSMI). The FSMI divides the system stability margin into three levels, quantitively and linearly representing the frequency response capability of different power devices. Finally, to show the effectiveness and practicability of the FSMI, this paper establishes a simulation model with high wind energy penetration, including four machines and four zones in DigSILENT. Based on the FSMI, the frequency stability margins in different typical operating scenarios are divided into three zones: “Absolut secure”, “Secure” and “Relative secure”. The FSMI also shows the dominant frequency stability problem and the risk of system frequency instability for each zone. Considering the checking principles, the frequency stability margin is equivalently expanded by calculating the energy storage’s minimum frequency response capacity.

Employing cognitive interviewing to evaluate, improve and validate items for measuring the health-related quality of life of women diagnosed with ovarian cancer.

BackgroundUse of patient-reported outcome measures in clinical settings facilitate the delivery of better health care to improve patient health outcomes. Previously collected qualitative data indicated themes that could inform items for a health-related quality of life measure. This study investigated the content validity of items for inclusion in a new health-related quality of life measure suitable for patients with ovarian cancer.MethodsCognitive interviewing techniques were used with fourteen women diagnosed with ovarian cancer and at different times since diagnosis, to evaluate items derived from the previously collected qualitative dataset. A set of draft items was administered via telephone, Zoom and WhatsApp app together with questions on item meaning and wording. Interviews were transcribed and thematically analysed.ResultsFour broad themes emerged in relation to the questionnaire construction and comprehension of items: intent and clarity, wording, relevance and context, and overall questionnaire construct. All draft items were adjusted based on the interview findings. A final set of 38 health-related quality of life items comprised 7 items describing physical health and functioning, 21 describing emotional wellbeing and 10 items describing social wellbeing; each rated on a five-point frequency response scale. ConclusionThe items reflected a range of personal experiences associated with the patient clinical journey, creating a health-related quality of life tool specific to women diagnosed with ovarian cancer. The cognitive interviewing process established content validity for the tool, thereby, preparing it for field testing and evaluation of its psychometric properties. This study highlighted the fundamental role of cognitive interviewing during health-related quality of life questionnaire development to ensure that item content is grounded in patient feelings, functioning and meaning.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12905-022-01966-w.

Clarifying observed relationships between protective behavioral strategies and alcohol outcomes: The importance of response options.

Protective behavioral strategies (PBS), or harm-reduction behaviors that can potentially reduce alcohol consumption or associated problems, have been assessed in varied ways throughout the literature. Existing scales vary in focus (i.e., broad vs. narrow), and importantly, in response options (i.e., absolute frequency vs. contingent frequency). Absolute frequency conflates PBS use with number of drinking occasions, resulting in inconsistencies in the relationship between PBS use and alcohol outcomes, whereas contingent frequency is less precise, which could reduce power. The current study proposes the use of absolute frequencies to maximize precision, with an adjustment for number of drinking days to extricate PBS use from drinking occasions, resulting in a contingent score. Study 1 examined the associations between PBS subscales using the Strategy Questionnaire (Sugarman & Carey, 2007) and alcohol outcomes, finding that in raw score form the association between PBS and typical alcohol outcomes varied greatly from significantly positive to significantly negative, but adjusted score relationships were all consistent with harm reduction perspectives. In addition, curvilinear relationships with typical alcohol use were eliminated using the score adjustment, resulting in linear associations. Study 2 confirmed the findings from Study 1 with a more precise timeframe, additional alcohol assessments, and heavier college drinkers. The relationships between alcohol outcomes and PBS in raw score form were again varied, but became consistently negative using the score adjustment. Researchers examining PBS and related constructs should consider modifying current scales to include a precise frequency response scale that is adjusted to account for number of drinking occasions. (PsycINFO Database Record

The assessment of protective behavioral strategies: Comparing the absolute frequency and contingent frequency response scales.

The purpose of the present studies was to examine the effects of response scale on the observed relationships between protective behavioral strategies (PBS) measures and alcohol-related outcomes. We reasoned that an "absolute frequency" scale (stem: "how many times …"; response scale: 0 times to 11+ times) conflates the frequency of using PBS with the frequency of consuming alcohol; thus, we hypothesized that the use of an absolute frequency response scale would result in positive relationships between types of PBS and alcohol-related outcomes. Alternatively, a "contingent frequency" scale (stem: "When drinking … how often …"; response scale: never to always) does not conflate frequency of alcohol use with use of PBS; therefore, we hypothesized that use of a contingent frequency scale would result in negative relationships between use of PBS and alcohol-related outcomes. Two published measures of PBS were used across studies: the Protective Behavioral Strategies Survey (PBSS) and the Strategy Questionnaire (SQ). Across three studies, we demonstrate that when measured using a contingent frequency response scale, PBS measures relate negatively to alcohol-related outcomes in a theoretically consistent manner; however, when PBS measures were measured on an absolute frequency response scale, they were nonsignificantly or positively related to alcohol-related outcomes. We discuss the implications of these findings for the assessment of PBS.

Supplemental Material for The Assessment of Protective Behavioral Strategies: Comparing the Absolute Frequency and Contingent Frequency Response Scales

Supplemental Material for The Assessment of Protective Behavioral Strategies: Comparing the Absolute Frequency and Contingent Frequency Response Scales

Sustainable High Capacitance at High Frequencies: Metallic Aluminum–Polypropylene Nanocomposites

The high-frequency dielectric response of 0-3 polypropylene nanocomposites prepared with the activated metallocene polymerization catalyst [rac-ethylenebisindenyl]zirconium dichlororide absorbed on the native Al(2)O(3) surfaces of metallic aluminum nanoparticles is characterized. The nanocomposites produced are randomly dispersed in the polyolefin matrix with no visible defects that might degrade film dielectric properties. Electrical measurements show that as the volume fraction of Al nanoparticles is increased, the effective permittivity of the nanocomposites increases, with ε(r) values reaching ~10 at relatively low frequency (1 MHz). Because of the high permittivity and conductivity contrast between the metal nanoparticles and the polypropylene matrix, Maxwell-Wagner-Sillars theory can be applied to model the loss at high frequencies and provide insight into how the nanocomposite high frequency response scales with Al volume fraction. At higher Al nanoparticle volume fractions, mixing theories predict greater densities of nanoparticle aggregates, consistent with the experimentally observed shift of the dielectric relaxation to lower frequencies. Although these nanocomposites undergo the predicted initial dielectric relaxation with increasing frequency, the metallic nanoparticle complex permittivity imbues the higher Al volume fraction materials with relatively high, sustainable permittivities, 6, at frequencies as high as 7 GHz.

Using a New Learning Environment Questionnaire for Reflection in Teacher Action Research

This article reports the development, validation and use of an instrument designed to provide teachers with feedback information, based on students’ perceptions, about their classroom environments. The instrument was developed to provide teachers with feedback that they could use to reflect on their teaching practices and, in turn, guide the implementation of strategies to improve their learning environments. To determine the validity and reliability of the new instrument, data from 2043 grade 11 and 12 students from 147 classes in 9 schools were analysed. The Rasch model was used to convert data collected using a frequency response scale into interval data that are suitable for parametric analyses. During an action research process, reflective journals, written feedback, discussions at a forum and interviews with eight teachers helped to illuminate the processes used by teachers during action research. This article reports the views of these teachers in general and examines more closely how one of the teachers used student responses to the learning environment questionnaire as a tool for reflection and as a guide in transforming her classroom environment. This case study helped us to gauge the extent to which action research based on students’ perceptions of the learning environment was useful in guiding teachers’ improvements of their classroom learning environments.

Relationship between perceived and actual frequency represented by common rating scale labels.

Two experiments investigated the relationship between subjective interpretation of frequency terms and corresponding objective values. Evidence supported the existence of a nonlinear relationship that is well described by a logarithmic function. The general form of this relationship was consistent across different methods of eliciting subjective frequency estimates and different frequency response scales. These findings, in combination with prior research, suggest that individuals can be highly accurate in reporting the frequency of prior experiences but that subjective reports using common frequency response scales and scoring methods should not be taken to reflect equal intervals of actual frequency. This bears similarity to psychophysical relationships observed between sensation and stimulus intensity, and it has implications for the interpretation and analysis of self-report measures that use Likert-type frequency response scales.

Evaluating an Integrated Science Learning Environment Using the Constructivist Learning Environment Survey

This article reports the validity and use of a new form of the Constructivist Learning Environment Survey (CLES). As part of a larger study, a comparative student version (CLES-CS) was developed to evaluate the impact of an innovative teacher development program (based on the Integrated Science Learning Environment, ISLE, model) in school classrooms. Two separate response blocks for 30 items comprising five scales are presented in side-by-side columns to measure students’ perceptions on a five-point frequency response scale of the extent to which certain psychosocial factors are prevalent in the science class taught by a teacher who had attended the ISLE program (THIS), as well as their perceptions of other science and non-science classes taught by other teachers in the same school (OTHER). The five scales of the CLES are called Personal Relevance, Uncertainty of Science, Shared Control, Critical Voice, and Student Negotiation. Using data collected from 1079 students in 59 classes in north Texas, principal components factor analysis with varimax rotation and Kaiser normalization confirmed the a priori structure of the CLES-CS. The factor structure, internal consistency reliability, discriminant validity, and the ability to distinguish between different classes and groups were supported for the CLES-CS. Students whose science teachers had attended the ISLE program (THIS) perceived higher levels of Personal Relevance and Uncertainty of Science in their classrooms relative to the classrooms of other science and non-science teachers in the same schools (OTHER). Similar results were found when comparing the classroom environment perceptions of students whose science teachers had attended the ISLE program with the perceptions of students whose science teacher had attended alternative field trip programs (non-ISLE).

A visual selectivity meter with a uniform decibel scale

Visual examination of the selectivity or frequency response of a filter by means of a frequency-modulated oscillator cathode-ray tube is well known, but few attempts have been made to produce a selectivity curve to a decibel scale. A very successful method, which depends on A. G. C.‡ action (virtually negative feedback), has been developed to give logarithmic delineation of frequency response, and the apparatus is described with particular reference to decibel scale production. The carrier or mid-frequency range of instrument is capable of variation from 50 to 1 500 kc./s., frequency-modulation ranges, giving band widths of 100, 20 and 10 kc./s. are possible. The decibel frequency response scale is “linear” over a range of 60 db. Check tests at three different carrier frequencies, 1 500, 500 and 100 kc./s., are described and show the performance of apparatus to be satisfactory and its degree of accuracy to be good.