2,579 research outputs found
Reliability and Validity of the Patient Health Questionnaire-4 Scale and Its Subscales of Depression and Anxiety Among Us Adults Based on Nativity
BACKGROUND: The burdens of anxiety and depression symptoms have significantly increased in the general US population, especially during this COVID-19 epidemiological crisis. The first step in an effective treatment for anxiety and depression disorders is screening. The Patient Health Questionnaire-4 (PHQ-4, a 4-item measure of anxiety/depression) and its subscales (PHQ-2 [a 2-item measure of depression] and Generalized Anxiety Disorder [GAD-2, a 2-item measure of anxiety]) are brief but effective mass screening instruments for anxiety and depression symptoms in general populations. However, little to no study examined the psychometric properties (i.e., reliability and validity) of the PHQ-4 and its subscales (PHQ-2 and GAD-2) in the general US adult population or based on US nativity (i.e., foreign-born vs. the US-born). We evaluated the psychometric properties of the PHQ-4 and its subscales in US adults, as well as the psychometric equivalence of the PHQ-4 scale based on nativity.
METHODS: We conducted a cross-sectional survey of 5,140 adults aged ≥ 18 years. We examined the factorial validity and dimensionality of the PHQ-4 with confirmatory factor analysis (CFA). A multiple-group confirmatory factor analysis (MCFA) was used to evaluate the comparability of the PHQ-4 across nativity groups. Reliability indices were assessed. Also, the scales\u27 construct validities were assessed by examining the associations of both the PHQ-4 and its subscales\u27 scores with the sociodemographic characteristics and the 3-item UCLA Loneliness scale.
RESULTS: The internal consistencies were high for the PHQ-4 scale (α = 0.92) and its subscales of PHQ-2 (α = 0.86) and GAD-2 (α = 0.90). The CFA fit indices showed evidence for the two-factor structure of the PHQ-4. The two factors (i.e., anxiety and depression) were significantly correlated (r = 0.92). The MCFA demonstrated measurement invariance of the PHQ-4 across the nativity groups, but the model fits the data better in the foreign-born group. There were significant associations of the PHQ-4 scale and its subscales\u27 scores with the sociodemographic characteristics and the UCLA Loneliness scale (all p \u3c 0.001).
CONCLUSIONS: The PHQ-4 and its subscales are reliable and valid measures to screen anxiety and depression symptoms in the general US adult population, especially in foreign-born individuals during the COVID-19 pandemic
Machine and transverse direction errors in webs: Diagnosis and remedies
The primary focus of web handling is often on tension control; however, equally important to almost any web handling or winding process is to maintain machine (MD) and transverse direction (TD) control of the web. This paper outlines a guide to loss of control or position of the web in both the machine and traverse direction on in handling over rollers or winding rolls. For each category of MD/TD errors in handling/winding, this paper covers: measurement, problems, root causes, and solutions tailored to each specific mechanism. This paper is not seeking to review the equations of traction or lateral control, which have been covered in many previous works, but to focus on the common problems of MD and TD control and target appropriate solutions
Optimizing nipped roller systems
Nipped rollers are central to many web converting processes - printing, coating, embossing, calendaring, and winding. Uniform products require uniform load and pressure from the nipping process. Uneven nipping not only creates product variations, but can lead to high levels of waste from web shifting, wrinkling, wound roll defects.Imperfections are inherent in nipping - from variations in roller diameters, product thickness, and roller deflection. For most nipped process, many variations are hidden by the compliance of a rubber roller covering. However, any nipped roller system has competing design factors. Hard rubber coverings last longer, but are less compliant. Smaller diameters create higher pressure, but will have more bending and deflection under uneven loading. Is there an answer or guideline to rubber roller mechanics besides "What did you use before?"This paper reviews the process of balancing rubber covering and roller design based on one simple goal: ensure roller bending deflections are less than rubber roller compliance. The models for rubber covering and roller deflection will be combined to give a clear view of this goal and provide design guidelines to ensure it is achieved. In addition, the paper will review methods to assess nipped process uniformity and remedies to create more uniform nipped processes
Taxonomy of wrinkles
Taxonomy is the practice and science of classification. Without taxonomy, everything is lumped into one pot and confusion prevails. All wrinkled or buckled webs should not be filed under one category. Just as birds are observed and divided by what they look like and where they appear wrinkled webs have characteristic visual clues and common causes. Much of taxonomy in other fields is justified by the ability to separate the good from the bad, such as managing invasive species. For wrinkles, all forms are considered invasive and undesirable, but taxonomy will help to understand the causes of specific wrinkles and help point the direction of either eliminating the cause or finding an appropriate remedy based on the cause.This paper outlines one approach to categorize wrinkling causes based on over twenty year's observations and the contributions of other experts of wrinkle prevention and elimination. This taxonomy divides buckled webs by three locations: in spans, on rollers, and within rolls. Buckled webs on rollers, the narrow definition of wrinkling, are divided into four mechanisms. Shear wrinkles, as defined by the work of Gehlbach, Good, and Kedl. Tracking wrinkles (or principle stress wrinkles) where the left and right sides of a web track toward the web's centerline (or other lane) with enough crossweb compressive stress to induce buckling. Constrained expansion wrinkles, such as develops in on-roller conduction or radiant heating or hygroscopic expansion in the outer wraps of a paper roll. Accumulation wrinkles, the only wrinkle species forming dominantly crossweb creases, where the compressive stresses build up in the machine direction. This paper includes over 50 examples of where these wrinkle mechanisms occurs despite our best efforts
SNP discovery and linkage mapping in Nicotiana
Abstract only availableWe are developing a genetic linkage map in F2 populations descended from a cross between Nicotiana plumbaginafolia and N. longiflora as well as the reciprocal cross. We are using an interspecific cross because is an outbreeder and is a self-pollinator. Combining our linkage map with estimates of self-fertilization in the F2 will allow us to make a Quantitative Trait Locus (QTL) map that may allow us to identify chromosome segments that are associated with self-pollination. We are concentrating on discovering new genetic markers. We are seeking SNPs (Single Nucleotide Polymorphisms) because they are co-dominant markers, i.e., both kinds of homozygotes and the heterozygote can be identified (e.g., AA, Aa, aa). In contrast, dominant markers can only identify the recessive homozygote unambiguously (aa); the dominant homozygote and the heterozygote are indistinguishable (AA = Aa). Therefore, co-dominant genetic markers are much more informative than dominant markers. We are seeking to identify genetic polymorphisms from known COS (Conserved Ortholog Set) loci because COS markers have been used to map many other species. Therefore, our linkage map will allow us to compare the chromosomal locations of these loci in our cross, versus other COS-mapped plants.In order to determine SNPs in the genome of Nicotiana, there are two possible approaches. We can sequence both parents of the F2 population and look for the differences between the two species as well as sequence the heterozygotes and look for differences within the F2. Thus far, we have tried 3 COS loci and found 1 polymorphism. We are using the CAPS procedure to assay the polymorphisms. We use restriction enzymes to cut at specific locations within the primer region and determine if each individual is homozygous dominant, homozygous recessive, or heterozygous.Life Sciences Undergraduate Research Opportunity Progra
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