1. Introduction and Overview. 2. Detecting Influential Observations and Outliers. 3. Detecting and Assessing Collinearity. 4. Applications and Remedies. 5. Research Issues and Directions for Extensions. Bibliography. Author Index. Subject Index.

Regression Diagnostics: Identifying Influential Data and Sources of Collinearity

Let's read! We will often find out this sentence everywhere. When still being a kid, mom used to order us to always read, so did the teacher. Some books are fully read in a week and we need the obligation to support reading. What about now? Do you still love reading? Is reading only for you who have obligation? Absolutely not! We here offer you a new book enPDFd the perception of the visual world to read.

The Perception of the Visual World. By James J. Gibson. U.S.A.: Houghton Mifflin Company, 1950 (George Allen & Unwin, Ltd., London). Price 35s.

4. Modelling Survival Data in Medical Research

In the SNPRM on advanced air bags, the National Highway Traffic Safety Administration (NHTSA) proposed a comprehensive set of injury criteria for evaluating the potential for injury to the head, neck, chest and lower extremities for the various dummy sizes, ranging from the 1-year-old child to the 50th percentile male. The comments received and the agency's responses are summarized in this paper and the various performance limits implemented in the final rule are shown in Table SES-1.In the SNPRM on advanced air bags, the National Highway Traffic Safety Administration (NHTSA) proposed a comprehensive set of injury criteria for evaluating the potential for injury to the head, neck, chest and lower extremities for the various dummy sizes, ranging from the 1-year-old child to the 50th percentile male. The comments received and the agency's responses are summarized in this paper and the various performance limits implemented in the final rule are shown in Table SES-1.

Supplement: development of improved injury criteria for the assessment of advanced automotive restraint systems - ii

The National Highway Traffic Safety Administration's (NHTSA) plans for upgrading the Federal Motor Vehicle Safety Standard (FMVSS) No. 208, frontal crash protection safety standard, include improving protection requirements for the normally seated mid-sized adult male, as well as including additional requirements that will specify performance limits to minimize the risks from airbags to small-sized occupants and children in both normal and out-of-position seating locations. These new crash specifications will require the use of additional dummies of various sizes as well as additional performance criteria that appropriately represent injury thresholds of these additional population segments. Based on the agency's analysis of comments received in response to the publication of the NPRM and the accompanying technical reports, the agency has made modifications to the recommended injury criteria and their associated performance limits. A detailed discussion of the comments received and the agency's analysis may be found in Appendix A. This report documents these modifications and the rationale.

/pdf/development-of-improved-injury-criteria-for-the-assessment-5bhqquzlql.pdf

Development of improved injury criteria for the assessment of advanced automotive restraint systems - ii

Blast-related traumatic brain injury is the most prevalent injury for combat personnel seen in the current conflicts in Iraq and Afghanistan, yet as a research community,we still do not fully understand the detailed etiology and pathology of this injury. Finite element (FE) modeling is well suited for studying the mechanical response of the head and brain to blast loading. This paper details the development of a FE head and brain model for blast simulation by examining both the dilatational and deviatoric response of the brain as potential injury mechanisms. The levels of blast exposure simulated ranged from 50 to 1000 kPa peak incident overpressure and 1–8 ms in positive-phase duration, and were comparable to real-world blast events. The frontal portion of the brain had the highest pressures corresponding to the location of initial impact, and peak pressure attenuated by 40–60% as the wave propagated from the frontal to the occipital lobe. Predicted brain pressures were primarily dependent on the peak overpressure of the impinging blast wave, and the highest predicted brain pressures were 30%less than the reflected pressure at the surface of blast impact. Predicted shear strain was highest at the interface between the brain and the CSF. Strain magnitude was largely dependent on the impulse of the blast, and primarily caused by the radial coupling between the brain and deforming skull.The largest predicted strains were generally less than 10%,and occurred after the shock wave passed through the head.For blasts with high impulses, CSF cavitation had a large role in increasing strain levels in the cerebral cortex and periventricular tissues by decoupling the brain from the skull. Relating the results of this study with recent experimental blast testing suggest that a rate-dependent strain-based tissue injury mechanism is the source primary blast TBI.

https://apps.dtic.mil/sti/pdfs/ADA581374.pdf

Development of a Finite Element Model for Blast Brain Injury and the Effects of CSF Cavitation

Traumatic brain injury (TBI) from blast produces a number of conundrums. This review focuses on five fundamental questions including: (1) What are the physical correlates for blast TBI in humans? (2) Why is there limited evidence of traditional pulmonary injury from blast in current military field epidemiology? (3) What are the primary blast brain injury mechanisms in humans? (4) If TBI can present with clinical symptoms similar to those of Post-Traumatic Stress Disorder (PTSD), how do we clinically differentiate blast TBI from PTSD and other psychiatric conditions? (5) How do we scale experimental animal models to human response? The preponderance of the evidence from a combination of clinical practice and experimental models suggests that blast TBI from direct blast exposure occurs on the modern battlefield. Progress has been made in establishing injury risk functions in terms of blast overpressure time histories, and there is strong experimental evidence in animal models that mild brain injuries occur at blast intensities that are similar to the pulmonary injury threshold. Enhanced thoracic protection from ballistic protective body armor likely plays a role in the occurrence of blast TBI by preventing lung injuries at blast intensities that could cause TBI. Principal areas of uncertainty include the need for a more comprehensive injury assessment for mild blast injuries in humans, an improved understanding of blast TBI pathophysiology of blast TBI in animal models and humans, the relationship between clinical manifestations of PTSD and mild TBI from blunt or blast trauma including possible synergistic effects, and scaling between animals models and human exposure to blasts in wartime and terrorist attacks. Experimental methodologies, including location of the animal model relative to the shock or blast source, should be carefully designed to provide a realistic blast experiment with conditions comparable to blasts on humans. If traditional blast scaling is appropriate between species, many reported rodent blast TBI experiments using air shock tubes have blast overpressure conditions that are similar to human long-duration nuclear blasts, not high explosive blasts.

Brain Injuries from Blast

Background: Blast injuries are becoming more common in modern war and terrorist action. This increasing threat underscores the importance of understanding and evaluating blast effects. Methods: For this study, data on more than 2,550 large animal experiments were collected from more than 50 experimental studies on blast. From this dataset, over 1,100 large animal experiments were selected with positive phase overpressure durations of 30 milliseconds or less. A two variable nonlinear logistic regression was performed on the experimental data for threshold injury and lethality in terms of pressure and duration. The effects of mass, pressure, and duration scaling were all evaluated. Results: New injury risk assessment curves were analyzed for both incident and reflected pressure conditions. Position dependent injury risk curves were also analyzed and were found to be unnecessary, at least for prone and side on conditions. Conclusions: The injury risk assessment showed good correlation to some of the existing injury assessments. It also showed good correspondence to a reported human case of blast exposure. Pressure scaling was analyzed to be unnecessary for these short duration exposures. Recommended injury assessments for various orientations relative to the incoming blast wave are included.

Pulmonary injury risk assessment for short-duration blasts.

Axial loading of the foot/ankle complex is an important injury mechanism in vehicular trauma that is responsible for severe injuries such as calcaneal and tibial pilon fractures. Axial loading may be applied to the leg externally, by the toepan and/or pedals, as well as internally, by active muscle tension applied through the Achilles tendon during pre-impact bracing. The objectives of this study were to investigate the effect of Achilles tension on fracture mode and to empirically model the axial loading tolerance of the foot/ankle complex. Blunt axial impact tests were performed on forty-three (43) isolated lower extremities with and without experimentally simulated Achilles tension. The primary fracture mode was calcaneal fracture in both groups. However, fracture initiated at the distal tibia more frequently with the addition of Achilles tension (p < 0.05). Acoustic sensors mounted to the bone demonstrated that fracture initiated at the time of peak local axial force. A survival analysis was performed on the injury data set using a Weibull regression model with specimen age, gender, body mass, and peak Achilles tension as predictor variables (R2 = 0.90). A closed-form survivor function was developed to predict the risk of fracture to the foot/ankle complex in terms of axial tibial force. The axial tibial force associated with a 50% risk of injury ranged from 3.7 kN for a 65 year-old 5th percentile female to 8.3 kN for a 45 year-old 50th percentile male, assuming no Achilles tension. The survivor function presented here may be used to estimate the risk of foot/ankle fracture that a blunt axial impact would pose to a human based on the peak tibial axial force measured by an anthropomorphic test device.

The axial injury tolerance of the human foot/ankle complex and the effect of Achilles tension.

Classifying behavior patterns in mouse models of neurological, psychiatric and neurodevelopmental disorders is critical for understanding disease causality and treatment. However, complete characterization of behavior is time-intensive, prone to subjective scoring, and often requires specialized equipment. Although several reports describe automated home-cage monitoring and individual task scoring methods, we report the first open source, comprehensive toolbox for automating the scoring of several common behavior tasks used by the neuroscience community. We show this new toolbox is robust and achieves equal or better consistency when compared to manual scoring methods. We use this toolbox to study the alterations in behavior that occur following blast-induced traumatic brain injury (bTBI), and study if these behavior patterns are altered following genetic deletion of the transcription factor Ets-like kinase 1 (Elk-1). Due to the role of Elk-1 in neuronal survival and proposed role in synaptic plasticity, we hypothesized that Elk-1 deletion would improve some neurobehavioral deficits, while impairing others, following blast exposure. In Elk-1 knockout (KO) animals, deficits in open field, spatial object recognition (SOR) and elevated zero maze performance after blast exposure disappeared, while new significant deficits appeared in spatial and associative memory. These are the first data suggesting a molecular mediator of anxiety deficits following bTBI, and represent the utility of the broad screening tool we developed. More broadly, we envision this open-source toolbox will provide a more consistent and rapid analysis of behavior across many neurological diseases, promoting the rapid discovery of novel pathways mediating disease progression and treatment.

/pdf/an-open-source-toolbox-for-automated-phenotyping-of-mice-in-1ddmij5ad0.pdf

Cameron R. Bass

Papers

Development of a Finite Element Model for Blast Brain Injury and the Effects of CSF Cavitation

Brain Injuries from Blast

Pulmonary injury risk assessment for short-duration blasts.

The axial injury tolerance of the human foot/ankle complex and the effect of Achilles tension.

An open-source toolbox for automated phenotyping of mice in behavioral tasks