Improved Coefficient and Variance Estimation in Stable First-Order Dynamic Regression Models

In dynamic regression models the least-squares coefficient estimators are biased in finite samples, and so are the usual estimators for the disturbance variance and for the variance of the coefficient estimators. By deriving the expectation of the initial terms in an expansion of the usual expression for the asymptotic coefficient variance estimator and by comparing these with an approximation to the true variance we find an approximation to the bias in variance estimation from which a bias corrected estimator for the variance readily follows. This is also achieved for a bias corrected coefficient estimator and allows to compare analytically the second-order approximation to the mean squared error of the least-squares estimator and its counterpart for the first-order bias corrected coefficient estimator. Two rather strong results on efficiency gains through bias correction for AR(1) models follow. Illustrative simulation results on the magnitude of bias in coefficient and variance estimation and on the scope for effective bias correction and efficiency improvement are presented for some relevant particular cases of the ARX(1) class of models.

Crystal structure of human IPS-1/MAVS/VISA/Cardif caspase activation recruitment domain

Background: IPS-1/MAVS/VISA/Cardif is an adaptor protein that plays a crucial role in the induction of interferons in response to viral infection. In the initial stage of the intracellular antiviral response two RNA helicases, retinoic acid inducible gene-I (RIG-I) and melanoma differentiation-association gene 5 (MDA5), are independently able to bind viral RNA in the cytoplasm. The 62 kDa protein IPS-1/MAVS/VISA/Cardif contains an N-terminal caspase activation and recruitment (CARD) domain that associates with the CARD regions of RIG-I and MDA5, ultimately leading to the induction of type I interferons. As a first step towards understanding the molecular basis of this important adaptor protein we have undertaken structural studies of the IPS-1 MAVS/VISA/Cardif CARD region. Results: The crystal structure of human IPS-1/MAVS/VISA/Cardif CARD has been determined to 2.1 angstrom resolution. The protein was expressed and crystallized as a maltose-binding protein (MBP) fusion protein. The MBP and IPS-1 components each form a distinct domain within the structure. IPS-1/MAVS/VISA/Cardif CARD adopts a characteristic six-helix bundle with a Greek-key topology and, in common with a number of other known CARD structures, contains two major polar surfaces on opposite sides of the molecule. One face has a surface-exposed, disordered tryptophan residue that may explain the poor solubility of untagged expression constructs. Conclusion: The IPS-1/MAVS/VISA/Cardif CARD domain adopts the classic CARD fold with an asymmetric surface charge distribution that is typical of CARD domains involved in homotypic protein-protein interactions. The location of the two polar areas on IPS-1/MAVS/VISA/Cardif CARD suggest possible types of associations that this domain makes with the two CARD domains of MDA5 or RIG-I. The N-terminal CARD domains of RIG-I and MDA5 share greatest sequence similarity with IPS-1/MAVS/VISA/Cardif CARD and this has allowed modelling of their structures. These models show a very different charge profile for the equivalent surfaces compared to IPS-1/MAVS/VISA/Cardif CARD.Publisher PDFPeer reviewe

Emotional Regulation and Interpersonal Effectiveness as Mechanisms of Change for Treatment Outcomes Within a DBT Program for Adolescents

Predictive modeling was used to identify the degree that hypothesized moderators of dialectical behavioral therapy for adolescents (DBT-A) treatment outcomes predicted anxiety and depression symptoms over time. Participants were 66 adolescents (41 girls; 25 boys) with a mean age of 15.38 years (SD = 1.51) who completed a 7-week DBT-A intervention. Analyses revealed convergent models, wherein emotion regulation and interpersonal effectiveness were substantial predictors of change in the symptoms of anxiety, F(4, 65) = 23.21, p \u3c .01, R2 = .60, and depression, F(4, 65) = 29.76, p \u3c .01, R2 = .66

Anchoring effects in the development of false childhood memories

When people receive descriptions or doctored photos of events that never happened, they often come to remember those events. But if people receive both a description and a doctored photo, does the order in which they receive the information matter? We asked people to consider a description and a doctored photograph of a childhood hot air balloon ride, and we varied which medium they saw first. People who saw a description first reported more false images and memories than people who saw a photo first, a result that fits with an anchoring account of false childhood memories

The thermal contact resistance of lubricant films in vacuum

This paper presents the results of an experimental investigation on the thermal contact resistance of lubricant films and bare interfaces. The apparatus and procedure used in the determination of these resistances are described. Twelve series of tests were performed to evaluate the effects of temperature and contact pressure on the thermal resistance of lubricant films. Variations of thermal contact resistance with temperature and contact pressure for four lubricants and for bare interfaces are presented graphically. The thermal resistances of the four lubricants tested in vacuum conditions: lithium grease, graphite grease, molykote grease, and silicone lubricant, were found to lie in the range from 0.0004 to 0.0035 hr sq ft F/Btu. The thermal resistances of the four lubricants in vacuum were lower than the thermal resistance for bare interfaces in air, and one order of magnitude lower than the thermal resistance of bare interfaces in vacuum. The molykote grease was least affected by temperature --Abstract, page ii