Reinsuring Group Revenue Insurance with Exchange-Provided Revenue Contracts

Shows that it is feasible to use exchange-based contracts as a substitute for the Standard Reinsurance Agreement. The authors analyze a Group Revenue Contract, which would allow producers to guarantee against reductions in county-level revenues. The insurance company would then purchase put options on an exchange-based revenue contract to protect against statewide revenue shortfalls. The analysis suggests that this reassurance tool would eliminate most though not all of the systemic risk associated with this product

Functional amyloids promote retention of public goods in bacteria

The growth and virulence of bacteria depends upon a number of factors that are secreted into the environment. These factors can diffuse away from the producing cells, to be either lost or used by cells that do not produce them (cheats). Mechanisms that act to reduce the loss of secreted factors through diffusion are expected to be favoured. One such mechanism may be the production of Fap fibrils, needle-like fibres on the cell surface observed in P. aeruginosa, which can transiently bind several secreted metabolites produced by cells. We test whether Fap fibrils help retain a secreted factor, the iron-scavenging molecule pyoverdine, and hence reduce the potential for exploitation by non-producing, cheating cells. We found that: (i) wild-type cells retain more iron-chelating metabolites than fibril non-producers; (ii) purified Fap fibrils can prevent the loss of the iron-chelators PQS (Pseudomonas quinolone signal) and pyoverdine; and (iii) pyoverdine non-producers have higher fitness in competition with fibril non-producers than with wild-type cells. Our results suggest that by limiting the loss of a costly public good, Fap fibrils may play an important role in stabilizing cooperative production of secreted factors

Cell death regulation in Drosophila: Conservation of mechanism and unique insights

Programmed cell death, or apoptosis, is a genetically encoded form of cell suicide that results in the orderly death and phagocytic removal of excess, damaged, or dangerous cells during normal development and in the adult. The cellular machinery required to carry out apoptosis is present in most, if not all cells, but is only activated in cells instructed to die (for review see Jacobson et al. 1997). Here, we review cell death regulation in the fly in the context of a first pass look at the complete Drosophila genome and what is known about death regulation in other organisms, particularly worms and vertebrates

Carcinoma of the Tail of the Pancreas Presenting As Acute Abdomen

Context Large bowel obstruction with perforation is an anomalous presentation of pancreatic tail carcinoma. Pancreatic cancer is often difficult to diagnose clinically and is especially furtive when it is located in the tail of the pancreas. Case report We describe a patient who presented with large bowel obstruction due to splenic flexure mass which proved to be due to pancreatic mucinous adenocarcinoma. Conclusions Pancreatic adenocarcinoma can rarely have the same presentation as colon cancer, and should therefore be considered in the differential diagnosis of large bowel obstruction

Physics based calibration of the Herschel/SPIRE bolometers

The bolometers (and readout circuitry) in the SPIRE instrument on the Herschel Space Observatory are among the best understood and well characterised of any sub‐mm astronomy instrument to date. SPIRE contains five arrays of NTD germanium spiderweb bolometers with up to 139 pixels per array. Their behaviour has been shown to be extremely stable as seen by repeated measurements in the years between initial array level and final instrument level tests, and can be described extremely well by a simple physical model (the ideal bolometer model). Calibration of the bolometers must take into account the non‐linear response when viewing bright sources, and the effect of fluctuations in the heat sink temperature. The simple and well‐understood behaviour of the detectors, coupled with the stable conditions expected in flight, mean that in contrast to previous sub‐mm instruments, physical models can be used to improve or possibly replace empirical calibration methods. We describe how this can be done, and use the large amount of data from ground measurements to show that we can use models to accurately calculate the absolute power detected by the bolometers

Understanding the Herschel-SPIRE bolometers

Bolometers are very simple devices. In principle, the behaviour of a bolometer can be described by a simple model along with a small number of parameters. The SPIRE instrument for the Herschel Space Observatory contains five arrays of NTD germanium spiderweb bolometers containing up to 139 pixels. We show from characterisation measurements on the ground using the flight read-out system that the bolometers follow the ideal model extremely well, are very stable, and that the read-out system is sufficiently well behaved to take advantage of this. Calibration should be greatly simplified by being able to take advantage of this behaviour