Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Metamodelling Messages Conveyed in Five Statistical Mechanical Textbooks from 1936 to 2001

Modelling is a significant aspect of doing physics and it is important how this activity is taught. This paper focuses on the explicit or implicit messages about modelling conveyed to the student in the treatments of phase transitions in statistical mechanics textbooks at beginning graduate level. Five textbooks from the 1930s to the present are analysed with respect to their messages about the following issues: What is a good model? What is the purpose of modelling? What does it mean to understand a natural phenomenon? It is argued that these texts give the student quite different perceptions of these issues and thus what of it means to do physics

Emergence, longevity and fecundity of Trissolcus basalis and Telenomus podisi after cold storage in the pupal stage Emergência, longevidade e fecundidade de Trissolcus basalis e Telenomus podisi após estocagem no estágio pupal

Pupae of Trissolcus basalis (Wollaston) and Telenomus podisi Ashmead (Hymenoptera: Scelionidae) were stored at 12&ordm;C and 15&ordm;C for 120-210 days, after different periods of parasitism at 18&ordm;C in order to evaluate adult emergence, longevity and ovipositional capacity. There was no emergence of adults at 12&ordm;C. The rate of emergence of parasitoids transferred to 15&ordm;C at the beginning of the pupal stage was 1.5% and 26.3%, for T. basalis and T. podisi respectively, whereas those parasitoids transferred one day before the expected date of emergence at 18&ordm;C showed 86.4% of emergence for T. basalis and 59.9% for T. podisi. Mean adult longevity was also significantly lower when pupae were transferred to 15&ordm;C at the beginning of the pupal stage. Females emerged after storage and maintained for 120 to 210 days at 15&ordm;C parasitized host eggs after transference to 25&ordm;C; however, fecundity of T. podisi was reduced in about 80% after cold storage.<br>Pupas de Trissolcus basalis (Wollaston) e Telenomus podisi Ashmead (Hymenoptera: Scelionidae) armazenadas a 12&ordm;C e 15&ordm;C por 120 a 210 dias, após diferentes períodos de parasitismo a 18&ordm;C, foram avaliadas quanto à emergência, longevidade e capacidade de parasitismo dos adultos. Não houve emergência de adultos a 12&ordm;C. Os índices de emergência de parasitóides transferidos a 15&ordm;C no início do estágio pupal foram 1,5% e 26,3%, em T. basalis e T. podisi, respectivamente, enquanto os transferidos um dia antes da data prevista para a emergência dos adultos a 18&ordm;C apresentaram índices de emergência de 86,4% em T. basalis e 59,9% em T. podisi. De forma semelhante, a longevidade média dos adultos foi significativamente menor quando a transferência para 15&ordm;C foi realizada no início do estágio pupal. Fêmeas emergidas após estocagem das pupas e mantidas por 120 a 210 dias a 15&ordm;C parasitaram ovos hospedeiros após transferência para 25&ordm;C; no entanto, a fecundidade de T. podisi foi reduzida em cerca de 80% quando mantida em baixa temperatura