A new displacement-based approach to calculate stress intensity factors with the boundary element method

The analysis of cracked brittle mechanical components considering linear elastic fracture mechanics is usually reduced to the evaluation of stress intensity factors (SIFs). The SIF calculation can be carried out experimentally, theoretically or numerically. Each methodology has its own advantages but the use of numerical methods has be-come very popular. Several schemes for numerical SIF calculations have been developed, the J-integral method being one of the most widely used because of its energy-like formulation. Additionally, some variations of the J-integral method, such as displacement-based methods, are also becoming popular due to their simplicity. In this work, a simple displacement-based scheme is proposed to calculate SIFs, and its performance is compared with contour integrals. These schemes are all implemented with the Boundary Element Method (BEM) in order to exploit its advantages in crack growth modelling. Some simple examples are solved with the BEM and the calculated SIF values are compared against available solutions, showing good agreement between the different schemes

Self-disorders and clinical high risk for psychosis: An empirical study in help-seeking youth attending community mental health facilities

Anomalous subjective experiences involving an alteration of the basic sense of self (ie, Self-disorder [SD]) are emerging as a core marker of schizophrenia spectrum disorders with potential impact on current early detection strategies as well. In this study, we wished to field-test the prevalence of SD in a clinical sample of adolescent/young adult help-seekers at putative risk for psychosis attending standard community mental health facilities in Italy. Participants (n = 47), aged between 14 and 25, underwent extensive psychopathological evaluations with current semi-structured tools to assess Clinical High Risk (CHR) state (ie, Structured Interview for Prodromal Syndromes/Scale of Prodromal Symptoms [SIPS/SOPS], Schizophrenia Proneness Instrument-Adult/Child and Youth [SPI-A/CY]). SD aggregated in CHR subjects as compared to the non-CHR and revealed substantial association with sub-psychotic symptoms (SIPS), subjective experience of cognitive and cognitive-perceptual vulnerability (basic symptoms) and functional level (Global Assessment of functioning). Moreover, a combination of the 2 approaches (ie, CHR plus SD) enabled further closing-in on a subgroup of CHR with lower global functioning. The results confirm SD's relevance for the early profiling of youths at potential high risk for psychosis

Rapid disease progression in HIV-1 perinatally infected children born to mothers receiving zidovudine monotherapy during pregnancy. The Italian register for HIV Infection in Children.

OBJECTIVE: To investigate the outcome in children perinatally infected with HIV-1 whose mothers received zidovudine (ZDV) monotherapy in pregnancy. DESIGN: Observational retrospective study of a prospectively recruited cohort. SETTING: Italian Register for HIV Infection in Children. PATIENTS: A group of 216 children perinatally infected with HIV-1, born in 1992-1997 and derived prospectively from birth: 38 children had mothers receiving ZDV monotherapy and for 178 children the mothers received no antiretroviral treatment during pregnancy. MAIN OUTCOME MEASURES: The estimated probability of developing severe disease or severe immune suppression, survival probability [95% confidence interval (CI)] within 3 years, and the hazard ratio (95% CI), adjusted for year of birth, maternal clinical condition at delivery, birthweight and treatments (Pneumocystis carinii pneumonia chemoprophylaxis and/or antiretroviral therapy before the onset of severe disease, severe immune suppression or death) were compared. RESULTS: Comparison of HIV-1-infected children whose mothers were treated with ZDV with children whose mothers were not treated showed that the former group had a higher probability of developing severe disease [57.3% (95% CI 40.9-74.3) versus 37.2% (95% CI 30.0-45.4); log-rank test 7.83, P = 0.005; adjusted hazard ratio 1.8 (95% CI 1.1-3.1)] or severe immune suppression [53.9% (95% CI 36.3-73.5) versus 37.5% (95% CI 30.0-46.2); log-rank test 5.58, P = 0.018; adjusted hazard ratio 2.4, (95% CI: 1.3-4.3)] and a lower survival [72.2% (95% CI 50.4-85.7) versus 81.0% (95% CI 73.7-86.5); log-rank test 4.23, P = 0.039; adjusted hazard ratio of death 1.9 (95% CI 1.1-3.6)]. CONCLUSIONS: This epidemiological observation could stimulate virologic studies to elucidate whether this rapid progression depends on in utero infection or transmission of resistant virus. Findings may suggest a need to hasten HIV-1 diagnosis in infants of ZDV-treated mothers and undertake an aggressive antiretroviral therapy in those found to be infecte