Two new Miocene limpets (Fissurellidae) from southern California, with notes on other fossil occurrences of the family in northwestern North America

Two new fissurellid limpets (Mollusca: Gastropoda: Fissurellidae), Fissurella? stantoni n. sp. and Scelidotoma aldersoni n. sp., are described from Miocene deposits in southern California. Fissurella? stantoni is described from a single specimen from the middle Miocene Topanga Canyon Formation in the Santa Monica Mountains, Los Angeles County, California. Scelidotoma aldersoni is described from two specimens, one from the middle Miocene Topanga Canyon Formation, and another provisionally (cf.) identified specimen of an internal mold from the middle Miocene “Vaqueros” Formation on Santa Cruz Island, Santa Barbara County, southern California. Other unreported fossil occurrences of Scelidotoma are a juvenile specimen attributed only to genus collected in the middle Eocene Crescent Formation in Washington state and S. bella from the Pliocene part of the San Diego Formation, San Diego County, California. The Scelidotoma occurrences extend the chronostratigraphic range of S. bella from the Holocene (living) to the middle Pliocene, and the range of the genus back to the middle Eocene

On modeling quantities for insurer solvency against catastrophe under some Markovian assumptions

Insurance companies sometimes face catastrophic losses, yet they must remain solvent enough to meet the legal obligation of covering all claims. Catastrophes can result in large damages to the policyholders, causing the arrival of numerous claims to insurance companies at once. Furthermore, the severity of an event could impact the time until the next occurrence. An insurer needs certain levels of startup capital to meet all claims, and then must have adequate reserves on a continual basis, even more so when catastrophes occur. This work examines two facets of these matters: for an infinite time horizon, we extend and develop models for insurer bankruptcy-related quantities accounting for the reality of large claims occurring. Meanwhile, for finite time horizons, we model the present value of claims that have been incurred but not yet reported, so-called \u27IBNR\u27 claims. In the former, we show how our method for \u27Gerber-Shiu\u27 functions works in a recently proposed dependency structure allowing insurers to charge clients different premiums depending on their riskiness. In the latter, we build upon a recent method which allowed claims to arrive in batches; besides permitting discounting to be time-dependent, we allow the insurer to adjust the assumed distribution of the time until the next event by comparing the number of claims from the current event to any number of random intervals. We provide numerical studies for both scenarios --Abstract, page iii

narrative-based knowledge sharing in the oil exploration industry

This study extends theory and research on narrative-based knowledge sharing in organizational communities. An empirical case study examines the role of narratives and knowledge sharing in a virtual community of practice at Shell Int. Exploration and Production. The focus of analysis is on how engineers facing urgent drilling problems make use of narratives provided by peers in order to find solutions. Findings confirm on the one hand the importance of narratives for problem solving in this highly sophisticated and virtual context (former studies focussed exclusively on face to face interaction on the shop floor level). On the other hand, the results indicated that the narratives told do not represent a coherent entity but rather a complex variety which is likely to irritate and confuse users. The conclusion drawn is that organizations cannot refrain from qualifying narratives generated in their communities. It is necessary in order to get orientation out of narrative variety. Finally, suggestions for establishing evaluation procedures are provided. More generally, the findings of the paper stress the importance of reflecting on narratives

Plantar Vein Thrombosis due to Busy Night Duty on Intensive Care Unit

A 32-year-old woman with severe foot pain came to our emergency department after a busy night duty in hospital followed by an extended sleep period. Physical examination revealed a discrete swelling of the medial aspect of the right foot and a painful plantar arch during digital examination. Magnetic resonance imaging (MRI) with intravenous gadolinium showed filling efects in the lateral plantar vein. Doppler sonography displayed noncompressible structures in the plantar veins without flow signals, suggesting a plantar vein thrombosis. Therapy was initiated with low-molecular-weight heparin in combination with customized elastic bandages for the lower leg. Follow-up sonography 6 weeks later showed complete patency of the plantar veins. To our knowledge, we present the first case of isolated plantar vein thrombosis independent of trauma, surgery, or malignant disease, most probably caused by a busy night duty on the intensive care unit (ICU) followed by a prolonged sleeping period

Root-rot diseases of the rubber tree in the Ivory Coast : 1. Severity, dynamics, and characterization of epidemics

Une enquête épidémiologique a été menée pendant 6 ans dans une jeune plantation d'hévéa (#Hevea brasiliensis Willd. ex A. Juss) afin d'étudier et de prévoir le développement des champignons agents de pourridié, #Rigidoporus lignosus (Klotzsch) Imazeki et #Phellinus noxius$ (Corner) G. Cunn. Pendant cette période, la contamination et la mortalité de ces arbres ont été systématiquement prises en compte tous les 6 mois. Durant la première année, on a assisté à une explosion de la maladie se traduisant par l'accroissement des foyers initiaux et par l'apparition de nouveaux. A compter de la sixième année après la plantation, on a observé un net fléchissement des activités parasitaires possiblement lié à l'augmentation des capacités réactionnelles des arbres avec l'âge ainsi qu'à la rupture des liens trophiques entre l'inoculum et les racines des arbres en état de décomposition. Le type de maladie pouvant caractériser ces pourridiés est discuté, essentiellement, sur la base des cinétiques d'apparition des foyers parasitaires. (Résumé d'auteur