DC4

Background: The 4-item version of the Center of Epidemiological Studies Depression Scale (CES-DC 4 ) is a self-reported questionnaire used to measure depressive symptoms in adolescents, but the psychometric properties of the scale have been tested to only a limited extent. The aim of this study was to examine the reliability and structural validity of the Danish CES-DC 4 in 9 th graders. Methods: Using a sample of 72 adolescents 15 to 17 years of age from five 9 th grade classes, the reliability of the CES-DC 4 was determined by a test-retest study at a 2-week interval. Descriptive statistics of the adolescents were presented, and internal consistency, structural validity, reliability, and agreement between tests were evaluated. The structural validity of the scale was tested by confirmatory factor analysis (CFA), and the sumscores of the test and retest were presented. Results: The estimated Cronbach's α was 0.61 (95% CI 0.50; 0.71). Inter-item and item-rest correlations indicated that one of the four items (item 20) did not fit well on the scale. CFA found a one-factor model suited for the scale, but the factor loadings indicated that item 20 contributed the least to measure the factor (0.29). Sum scores ranged from 0-9 within a possible interval of 0-12. There were no signs of systematic error of the scale. Limits of Agreement (-3.01; 3.79) were broad. The standard error of measurement (SEM = 1.25 point (95% CI.1.05; 1.47)) and intraclass correlation (ICC(2,1) = 0.60 (95% CI: 0.44; 0.73)) calculations showed low reliability of the CES-DC 4 . Conclusion: This study found low reliability of the CES-DC 4 with low estimates of ICC and Cronbach's α. The CES-DC 4 needs revision, and removal of item 20 and adding more items from the CES-DC should be considered.

Brazil has the second-largest dairy cattle herd in the world, and bovine mastitis still can cause significant losses for dairy farmers. Despite this fact, little information is available about milk microbial composition of Brazilian dairy cows, as well as the potential use of bacteriophages in the control of S. aureus. Here, we investigated milk bacterial composition of 28 Holstein Fresian cows (109 teats), selected in the dry-off period, using 16S rRNA analysis. Furthermore, a representative S. aureus strain (UFV2030RH1) was obtained at drying-off for isolation of a bacteriophage (vB_SauM-UFV_DC4, UFV_DC4) and bacterial genomic comparison purposes. Our outcomes revealed that Staphylococcus was the third most prevalent genus and positively correlated with subclinical mastitis events. As a major finding, genomic analyses showed the presence of adhesive matrix molecules that recognize microbial surface components (MSCRAMM) in UFV2030RH1 and might indicate great biofilm formation capability. A minimum inhibitory concentration (MIC) assay showed that resistance to ampicillin was the highest among the antibiotic tested in S. aureus 3059 and UFV2030RH1, displaying values four and sixteen times greater than MIC resistance breakpoint, respectively. Together, our results suggest that Staphylococcus is highly prevalent in dairy cows at drying-off and the use of the phage UFV_DC4 as a biocontrol agent must be investigated in future studies.