Elastic (stress-strain) halo associated to ion-induced nano-tracks in lithium niobate: role of crystal anisotropy

The elastic strain/stress fields (halo) around a compressed amorphous nano-track (core) caused by a single high-energy ion impact on LiNbO3 are calculated. A method is developed to approximately account for the effects of crystal anisotropy of LiNbO3 (symmetry 3m) on the stress fields for tracks oriented along the crystal axes (X, Y or Z). It only considers the zero-order (axial) harmonic contribution to the displacement field in the perpendicular plane and uses effective Poisson moduli for each particular orientation. The anisotropy is relatively small; however, it accounts for some differential features obtained for irradiations along the crystallographic axes X, Y and Z. In particular, the irradiation-induced disorder (including halo) and the associated surface swelling appear to be higher for irradiations along the X- or Y-axis in comparison with those along the Z-axis. Other irradiation effects can be explained by the model, e.g. fracture patterns or the morphology of pores after chemical etching of tracks. Moreover, it offers interesting predictions on the effect of irradiation on lattice parameter

The Edinburgh Postnatal Depression Scale (EPDS): translation and validation study of the Iranian version

BACKGROUND: The Edinburgh Postnatal Depression Scale (EPDS) is a widely used instrument to measure postnatal depression. This study aimed to translate and to test the reliability and validity of the EPDS in Iran. METHODS: The English language version of the EPDS was translated into Persian (Iranian language) and was used in this study. The questionnaire was administered to a consecutive sample of 100 women with normal (n = 50) and caesarean section (n = 50) deliveries at two points in time: 6 to 8 weeks and 12 to 14 weeks after delivery. Statistical analysis was performed to test the reliability and validity of the EPDS. RESULTS: Overall 22% of women at time 1 and 18% at time 2 reported experiencing postpartum depression. In general, the Iranian version of the EPDS was found to be acceptable to almost all women. Cronbach's alpha coefficient (to test reliability) was found to be 0.77 at time 1 and 0.86 at time 2. In addition, test-rest reliability was performed and the intraclass correlation coefficient was found to be 0.80. Validity as performed using known groups comparison showed satisfactory results. The questionnaire discriminated well between sub-groups of women differing in mode of delivery in the expected direction. The factor analysis indicated a three-factor structure that jointly accounted for 58% of the variance. CONCLUSION: This preliminary validation study of the Iranian version of the EPDS proved that it is an acceptable, reliable and valid measure of postnatal depression. It seems that the EPDS not only measures postpartum depression but also may be measuring something more

Evaluation of the Edinburgh Post Natal Depression Scale using Rasch analysis

BACKGROUND: The Edinburgh Postnatal Depression Scale (EPDS) is a 10 item self-rating post-natal depression scale which has seen widespread use in epidemiological and clinical studies. Concern has been raised over the validity of the EPDS as a single summed scale, with suggestions that it measures two separate aspects, one of depressive feelings, the other of anxiety. METHODS: As part of a larger cross-sectional study conducted in Melbourne, Australia, a community sample (324 women, ranging in age from 18 to 44 years: mean = 32 yrs, SD = 4.6), was obtained by inviting primiparous women to participate voluntarily in this study. Data from the EPDS were fitted to the Rasch measurement model and tested for appropriate category ordering, for item bias through Differential Item Functioning (DIF) analysis, and for unidimensionality through tests of the assumption of local independence. RESULTS: Rasch analysis of the data from the ten item scale initially demonstrated a lack of fit to the model with a significant Item-Trait Interaction total chi-square (chi Square = 82.8, df = 40; p < .001). Removal of two items (items 7 and 8) resulted in a non-significant Item-Trait Interaction total chi-square with a residual mean value for items of -0.467 with a standard deviation of 0.850, showing fit to the model. No DIF existed in the final 8-item scale (EPDS-8) and all items showed fit to model expectations. Principal Components Analysis of the residuals supported the local independence assumption, and unidimensionality of the revised EPDS-8 scale. Revised cut points were identified for EPDS-8 to maintain the case identification of the original scale. CONCLUSION: The results of this study suggest that EPDS, in its original 10 item form, is not a viable scale for the unidimensional measurement of depression. Rasch analysis suggests that a revised eight item version (EPDS-8) would provide a more psychometrically robust scale. The revised cut points of 7/8 and 9/10 for the EPDS-8 show high levels of agreement with the original case identification for the EPDS-10

The utility of screening for perinatal depression in the second trimester among Chinese: a three-wave prospective longitudinal study

This paper aims to study the pattern of perinatal depressive symptomatology and determine the predictive power of second trimester perinatal depressive symptoms for future perinatal periods. A population-based sample of 2,178 women completed the Edinburgh Postnatal Depression Scale (EPDS) in the second and third trimesters and at 6 weeks postpartum. Repeated measures ANOVAs were used to determine the EPDS scores across three stages. The predictive power of the second trimester EPDS score in identifying women with an elevated EPDS score in the third trimester and at 6 weeks postpartum were determined. The predictive power of the second trimester EPDS score was further assessed using stepwise logistic regression and receiver operator characteristic curves. EPDS scores differed significantly across three stages. The rates were 9.9%, 7.8%, and 8.7% for an EPDS score of >14 in the second and third trimesters and at 6 weeks postpartum, respectively. Using a cut-off of 14/15, the second trimester EPDS score accurately classified 89.6% of women in the third trimester and 87.2% of those at 6 weeks postpartum with or without perinatal depressive symptomatology. Women with a second trimester EPDS score >14 were 11.78 times more likely in the third trimester and 7.15 times more likely at 6 weeks postpartum to exhibit perinatal depressive symptomatology after adjustment of sociodemographic variables. The area under the curve for perinatal depressive symptomatology was 0.85 in the third trimester and 0.77 at 6 weeks postpartum. To identify women at high risk for postpartum depression, healthcare professionals could consider screening all pregnant women in the second trimester so that secondary preventive intervention may be implemented

Aboriginal and Torres Strait Islander women's experience when interacting with the Edinburgh Postnatal Depression Scale: a brief note

Background: The Edinburgh Postnatal Depression Scale (EPDS) is one of the most widely used screening instruments for maternal perinatal anxiety and depression. It has maintained its robust performance when translated into multiple languages, when used prenatally and when used with perinatal fathers; thus the tool is also known as the Edinburgh Depression Scale (EDS). However, there have been no published psychometric data on versions of the EPDS adapted for screening Australian Aboriginal and Torres Strait Islander women. We describe the development of 'translations' of the EPDS and report their basic psychometric properties. Method: During the Queensland arm of the beyondblue National Postnatal Depression Program (2001–2005), partnerships with Aboriginal and Torres Strait Islander women were forged. At TAIHS' stand alone "Mums and Babies" unit 181 women of Aboriginal or Torres Strait Islander descent were recruited into the study through their antenatal and postnatal visits and 25 were recruited at Mt Isa. Participants completed either the translation or the standard version of the EPDS both antenatally and postnatally. Results: The 'translations' of the EPDS demonstrated a high level of reliability. The was a strong correlation between the 'translations' and the EPDS. The 'translations' and the standard EPDS both identified high rates of women at risk of depression although the 'translations' identified higher rates. Conclusion: We argue that the 'translation' may have been a more accurate predictor of perinatal women at risk for depression, but acknowledge that a lack of validity evidence weakens this conclusion