An actuarial approach to motor insurance rating

This thesis describes an actuarial structure for the practical analysis of motor insurance premium rating. An underlying theme emphasises that judgements are being made taking into account many factors e.g. economical, statistical and technical, therefore it is necessary to bring into the decision process a group of interested persons. In addition even though data are used to explain the proposed methods, it is the framework which is important and not the omission of some of the data e.g. important rating factors. The basis for premium projecting is discussed together with a critical discussion of various measures of surplus. A new measure is developed referred to as 'proposed to existing' which measures the effect of premium adjustments after taking into account the portfolio distribution. Another theme is to encourage a detailed within-portfolio analysis. An example, using data supplied by an Insurance Company helps to highlight the structure. The analysis commences by sub-dividing the data into important underwriting rating factors. The claim experience is further divided by claim proportions and the three main types of claims cost: accidental damage, third party property damage and third party bodily injury. By sub-dividing the data into multiway cells both exposure and claim numbers become very small, hence statistical modelling is used to smooth the data and to reduce variation. A critical review of past models in respect of claim proportions and accidental damage costs is made. In addition a pragmatic approach to third party bodily injury is carried out. To obtain an office premium the modelled claim experience is combined with economic factors such as inflation and expenses. Details of fitting the additive model by Orthogonal Weighted Least Squares is described. This converts the office premium into a 'points table'. An advantage of this 'points table' is that it can be used to compare various different sets of assumptions. A brief reference to the competitive market position is then made. An analysis of surplus is developed together with a worked example, which highlights the importance of claim proportions and the level of claims cost.Finally, the last chapter gives a summary of further research work which has been indicated as this thesis has developed

Early above- and below-ground responses of subboreal conifer seedlings to various levels of deciduous canopy removal

We examined the growth of understory conifers, following partial or complete deciduous canopy removal, in a field study established in two regions in Canada. In central British Columbia, we studied the responses of three species (Pseudotsuga menziesii var. glauca (Beissn.) Franco, Picea glauca (Moench) Voss x Picea engelmannii Parry ex Engelm., and Abies lasiocarpa (Hook.) Nutt.), and in northwestern Quebec, we studied one species (Abies balsamea (L.) Mill.). Stem and root diameter and height growth were measured 5 years before and 3 years after harvesting. Both root and stem diameter growth increased sharply following release but seedlings showed greater root growth, suggesting that in the short term, improvement in soil resource capture and transport, and presumably stability, may be more important than an increase in stem diameter and height growth. Response was strongly size dependent, which appears to reflect greater demand for soil resources as well as higher light levels and greater tree vigour before release for taller individuals. Growth ratios could not explain the faster response generally attributed to true fir species or the unusual swift response of spruces. Good prerelease vigour of spruces, presumably favoured by deciduous canopies, could explain their rapid response to release

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

An actuarial approach to motor insurance rating

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Comparing the Effects of Three Cognitive Tasks on Indicators of Mental Fatigue

This investigation assessed the impact of three cognitively demanding tasks on cognitive performance, subjective, and physiological indicators of mental fatigue. Following familiarization, participants completed four testing sessions, separated by 48 h. During each session, participants watched a 45-min emotionally neutral documentary (control) or completed one of the following computer tasks: Psychomotor Vigilance Task (PVT); AX-Continuous Performance Test (AX-CPT); or Stroop Task. Mental fatigue was assessed before and at regular periods for 60 min following the 45-min treatments. Cognitive performance was assessed using 3-min PVT, and task performance. Subjective assessments were conducted using the Brunel Mood Scale, and visual analog scales (VAS). Physiological indicators of mental fatigue included electroencephalography (EEG), and heart rate variability (HRV). Subjective ratings of mental fatigue increased from pre to 0-min post in all-treatments, but not the documentary (p < 0.05). Subjective fatigue (VAS) remained higher (p < 0.05) than pretreatment values for 20-, 50-, and 60-min following the PVT, Stroop, and AX-CPT respectively. The cognitively demanding tasks had unclear effects on 3-min PVT, EEG, and HRV assessments. Tasks requiring response inhibition appear to induce fatigue for longer durations than a simple vigilance task. Simple VAS appear to be the most practical method for assessing mental fatigue