Regulatory solvency prediction in property-liability insurance: risk-based capital, audit ratios, and cash flow simulation

This paper analyzes the accuracy of the principal models used by U.S. insurance regulators to predict insolvencies in the property-liability insurance industry and compares these models with a relatively new solvency testing approach--cash flow simulation. Specifically, we compare the risk-based capital (RBC) system introduced by the National Association of Insurance Commissioners (NAIC) in 1994, the FAST (Financial Analysis and Surveillance Tracking) audit ratio system used by the NAIC, and a cash flow simulation model developed by the authors. Both the RBC and FAST systems are static, ratio-based approaches to solvency testing, whereas the cash flow simulation model implements dynamic financial analysis. Logistic regression analysis is used to test the models for a large sample of solvent and insolvent property-liability insurers, using data from the years 1990-1992 to predict insolvencies over three-year prediction horizons. We find that the FAST system dominates RBC as a static method for predicting insurer insolvencies. Further, we find the cash flow simulation variables add significant explanatory power to the regressions and lead to more accurate solvency prediction than the ratio-based models taken alone.Insurance industry

Hedgehog Pathway Activation Alters Ciliary Signaling in Primary Hypothalamic Cultures

Primary cilia dysfunction has been associated with hyperphagia and obesity in both ciliopathy patients and mouse models of cilia perturbation. Neurons throughout the brain possess these solitary cellular appendages, including in the feeding centers of the hypothalamus. Several cell biology questions associated with primary neuronal cilia signaling are challenging to address in vivo. Here we utilize primary hypothalamic neuronal cultures to study ciliary signaling in relevant cell types. Importantly, these cultures contain neuronal populations critical for appetite and satiety such as pro-opiomelanocortin (POMC) and agouti related peptide (AgRP) expressing neurons and are thus useful for studying signaling involved in feeding behavior. Correspondingly, these cultured neurons also display electrophysiological activity and respond to both local and peripheral signals that act on the hypothalamus to influence feeding behaviors, such as leptin and melanin concentrating hormone (MCH). Interestingly, we found that cilia mediated hedgehog signaling, generally associated with developmental processes, can influence ciliary GPCR signaling (Mchr1) in terminally differentiated neurons. Specifically, pharmacological activation of the hedgehog-signaling pathway using the smoothened agonist, SAG, attenuated the ability of neurons to respond to ligands (MCH) of ciliary GPCRs. Understanding how the hedgehog pathway influences cilia GPCR signaling in terminally differentiated neurons could reveal the molecular mechanisms associated with clinical features of ciliopathies, such as hyperphagia-associated obesity

Managerial decision making under uncertainty: the case of Twenty20 cricket

We consider managerial decision making by examining the impact of decisions taken by cricket captains on Twenty20 International (T20I) match outcomes. In particular, we examine whether pressure from external commentators is associated with suboptimal decision making by captains. Using data from over 300 T20I matches, we find little evidence that either winning the toss or choosing to bat first improves the likelihood of winning. Despite this, we find that captains in T20I cricket are significantly more likely to choose to bat rather than bowl after winning the toss, a finding that is consistent with social pressure constraining captains’ decision making

Systematic review of the clinical effectiveness and cost-effectiveness, and economic evaluation, of denosumab for the treatment of bone metastases from solid tumours

Peer reviewedPublisher PD

Rationalizing the Different Products in the Reaction of N\u3csub\u3e2\u3c/sub\u3e with Three-coordinate MoL\u3csub\u3e3\u3c/sub\u3e Complexes

The reaction of N2 with three-coordinate MoL3 complexes is known to give rise to different products, N–MoL3, L3Mo–N–MoL3 or Mo2L6, depending on the nature of the ligand L. The energetics of the different reaction pathways are compared for L = NH2, NMe2, N(iPr)Ar and N(tBu)Ar (Ar = 3,5-C6H3Me2) using density functional methods in order to rationalize the experimental results. Overall, the exothermicity of each reaction pathway decreases as the ligand size increases, largely due to the increased steric crowding in the products compared to reactants. In the absence of steric strain, the formation of the metal–metal bonded dimer, Mo2L6, is the most exothermic pathway but this reaction shows the greatest sensitivity to ligand size varying from significantly exothermic, −403 kJ mol−1 for L = NMe2, to endothermic, +78 kJ mol−1 for L = N(tBu)Ar. For all four ligands, formation of N–MoL3via cleavage of the N2 bridged dimer intermediate, L3Mo–N–N–MoL3, is strongly exothermic. However, in the presence of excess reactant MoL3, formation of the single atom-bridged complex L3Mo–N–MoL3 from N–MoL3 + MoL3 is both thermodynamically and kinetically favoured for L = NMe2 and N(iPr)Ar, in agreement with experiment. In the case of L = N(tBu)Ar, the greater steric bulk of the tBu group results in a much less exothermic reaction and a calculated barrier of 66 kJ mol−1 to formation of the L3Mo–N–MoL3 dimer. Consequently, for this ligand, the energetically and kinetically favoured product, consistent with the experimental data, is the nitride complex L3Mo–N

Molecular mode-coupling theory applied to a liquid of diatomic molecules

We study the molecular mode coupling theory for a liquid of diatomic molecules. The equations for the critical tensorial nonergodicity parameters ${\bf F}_{ll'}^m(q)$ and the critical amplitudes of the $\beta$ - relaxation ${\bf H}_{ll'}^m(q)$ are solved up to a cut off $l_{co}$ = 2 without any further approximations. Here $l,m$ are indices of spherical harmonics. Contrary to previous studies, where additional approximations were applied, we find in agreement with simulations, that all molecular degrees of freedom vitrify at a single temperature $T_c$. The theoretical results for the non ergodicity parameters and the critical amplitudes are compared with those from simulations. The qualitative agreement is good for all molecular degrees of freedom. To study the influence of the cut off on the non ergodicity parameter, we also calculate the non ergodicity parameters for an upper cut off $l_{co}=4$. In addition we also propose a new method for the calculation of the critical nonergodicity parameterComment: 27 pages, 17 figure

Berenstein-Zelevinsky triangles, elementary couplings and fusion rules

We present a general scheme for describing su(N)_k fusion rules in terms of elementary couplings, using Berenstein-Zelevinsky triangles. A fusion coupling is characterized by its corresponding tensor product coupling (i.e. its Berenstein-Zelevinsky triangle) and the threshold level at which it first appears. We show that a closed expression for this threshold level is encoded in the Berenstein-Zelevinsky triangle and an explicit method to calculate it is presented. In this way a complete solution of su(4)_k fusion rules is obtained.Comment: 14 page

Tidal energy in the Bering Sea

Tidal harmonics computed from TOPEX/POSEIDON altimetry are assimilated into a barotropic, finite element model of the Bering Sea whose accuracy is evaluated though comparisons with independent bottom pressure gauges. The model is used to estimate energy fluxes through each of the Aleutian Passes and Bering Strait and to construct an energy budget for the major tidal constituents. The finite element model does not conserve mass locally and this is shown to give rise to an additional term in the energy budget whose contribution is significant for the prior model, but which is reduced substantially with the assimilation technique. Though the M2 constituent is estimated to have the largest net energy flux into the Bering Sea at 31.2 GW, the K1 constituent is not far behind at 24.9 GW and the sum for the three largest diurnal constituents is found to be greater than the sum for the largest three semi-diurnals. Samalga and Amutka Passes are found to be the primary conduits for influx of semi-diurnal energy while Amchitka Pass is the primary conduit for diurnal energy. A significant portion of the diurnal energy is seen to exist in the form of continental shelf waves trapped along Bering Sea slopes.The effect of the 18.6-year nodal modulation is estimated and found to cause basin-wide variations of approximately 19% in the net incoming tidal energy flux. Larger variations in the dissipation occur in subregions that are strongly dominated by the diurnal constituents, such as Seguam Pass and south of Cape Navarin. These variations should correlate with tidal mixing and may have important consequences for biological productivity, similar to those previously found for Pacific halibut recruitment (Parker et al., 1995) and shrimp, capelin, herring, cod, and haddock biomass in the Barents Sea (Yndestad, 2004)

The Persistence of Aboriginal Land Use: Fish and Wildlife Harvest Areas in the Hudson and James Bay Lowland, Ontario

The question of the extent and importance of contemporary aboriginal land use in the Canadian North remains controversial, despite more than 20 studies undertaken since the mid-1970s to document Native land claims and to assess impacts of development projects. In planning a community and regional development strategy that takes into account traditional land use and economy, methodologies were developed for a computer-based, integrated land use and wildlife harvest study that could be applied over large geographic areas. Wildlife harvesting areas used in 1990 by the aboriginal people of the Mushkegowuk region, Hudson and James Bay Lowland, were documented by interviewing 925 hunters from eight communities (Moose Factory, Moosonee, New Post, Fort Albany, Kashechewan, Attawapiskat, Peawanuck and Fort Severn). Results show that geographically extensive land use for hunting and fishing persists in the Mushkegowuk region, some 250 000 sq km. However, the activity pattern of Omushkego (West Main) Cree harvesters has changed much over the decades; contemporary harvesting involves numerous short trips of a few days' duration instead of the traditional long trips. Although the First Nations control only 900 sq km (0.36% of the region) as Indian reserve land, they continue to use large parts of their traditional territory.Key words: land use, aboriginal territories, Hudson Bay and James Bay Lowland, Canadian subarctic, Cree, subsistence, wildlife, fisheriesLa question du niveau et de l'importance de l'utilisation actuelle des terres aborigènes dans le Nord canadien demeure controversée, malgré plus de 20 études entreprises depuis le milieu des années 70 afin de documenter les revendications territoriales des autochtones et d'évaluer l'impact des projets de développement. Dans le but de planifier une stratégie de développement communautaire et régional qui tienne compte de l'utilisation des terres et de l'économie traditionnelles, on a mis au point des méthodologies pour une étude intégrée de l'utilisation des terres et prélèvement faunique, en se servant d'ordinateurs, méthodologies qui pourraient être appliquées à de vastes régions géographiques. On a documenté les zones de prélèvement faunique utilisées en 1990 par les peuples autochtones de la région de Mushkegowuk, basse-terre de la baie d'Hudson et de la baie James, en interviewant 925 chasseurs de huit communautés (Moose Factory, Moosonee, New Post, Fort Albany, Kashechewan, Attawapiskat, Peawanuck et Fort Severn). Les résultats montrent qu'une utilisation intensive, du point de vue géographique, pour la chasse et la pêche persiste dans la région de Mushkegowuk, soit quelque 250 000 km². Cependant, le type d'activité de prélèvement des Cree Omushkego (West Main) a beaucoup changé au cours des ans; les prélèvements contemporains sont réalisés lors de nombreuses expéditions de quelques jours seulement, plutôt que lors de longues expéditions traditionnelles. Bien que les Premières Nations ne contrôlent que 900 km² (0,36 p. cent de la région) en tant que terres de réserve indienne, elles continuent d'utiliser une grande superficies du territoire traditionnel.Mots clés: utilisation des terres, territoires autochtones, basse-terre de la baie d’Hudson et de la baie James, subarctique canadien, Cree, subsistance, faune, pêcherie

Test of mode coupling theory for a supercooled liquid of diatomic molecules. II. q-dependent orientational correlators

Using molecular dynamics computer simulations we study the dynamics of a molecular liquid by means of a general class of time-dependent correlators S_{ll'}^m(q,t) which explicitly involve translational (TDOF) and orientational degrees of freedom (ODOF). The system is composed of rigid, linear molecules with Lennard- Jones interactions. The q-dependence of the static correlators S_{ll'}^m(q) strongly depend on l, l' and m. The time dependent correlators are calculated for l=l'. A thorough test of the predictions of mode coupling theory (MCT) is performed for S_{ll}^m(q,t) and its self part S_{ll}^{(s)m}(q,t), for l=1,..,6. We find a clear signature for the existence of a single temperature T_c, at which the dynamics changes significantly. The first scaling law of MCT, which involves the critical correlator G(t), holds for l>=2, but no critical law is observed. Since this is true for the same exponent parameter lambda as obtained for the TDOF, we obtain a consistent description of both, the TDOF and ODOF, with the exception of l=1. This different behavior for l \ne 1 and l=1 can also be seen from the corresponding susceptibilities (chi'')_{ll}^m(q,omega) which exhibit a minimum at about the same frequency omega_{min} for all q and all l \ne 1, in contrast to (chi'')_{11}^m(q,omega) for which omega'_{min} approx 10 omega_{min} . The asymptotic regime, for which the first scaling law holds, shrinks with increasing l. The second scaling law of MCT (time-temperature superposition principle) is reasonably fulfilled for l \ne 1 but not for l=1. Furthermore we show that the q- and (l,m)-dependence of the self part approximately factorizes, i.e. S_{ll}^{(s)m}(q,t) \cong C_l^{(s)}(t) F_s(q,t) for all m.Comment: 11 pages of RevTex, 16 figure