Introducing IPv6 Tokenised Interface Identifiers into the Linux Kernel

IPv6 Stateless Address Autoconfiguration (SLAAC) enables network administrators to deploy devices in a network and have those devices automatically generate global addresses without any administrative intervention, and without the need for any stateful configuration service such as DHCPv6. However, certain services --- such as HTTP, SMTP and IMAP --- may better benefit from having "well known" identifiers that do not depend on the physical hardware address of the server's network interface card. Tokenised addresses offer facility for administrators to specify the bottom 64 bits of an IPv6 address for a node whilst allowing the top 64 bits (the network prefix) to be automatically configured from router advertisements. This report documents the approach taken and experience gained from introducing tokenised interface identifiers into the Linux 2.6.11 kernel, as shipped with Redhat Fedora Core 4. This proof of concept work demonstrates the relative ease of introducing this useful utility for network node deployment, and further motivates wider deployment of the semi-automatic configuration approach

Numerical Simulations of Radiatively-Driven Dusty Winds

[abridged] Radiation pressure on dust grains may be an important mechanism in driving winds in a wide variety of astrophysical systems. However, the efficiency of the coupling between the radiation field and the dusty gas is poorly understood in environments characterized by high optical depths. We present a series of idealized numerical experiments, performed with the radiation-hydrodynamic code ORION, in which we study the dynamics of such winds and quantify their properties. We find that, after wind acceleration begins, radiation Rayleigh-Taylor instability forces the gas into a configuration that reduces the rate of momentum transfer from the radiation field to the gas by a factor ~ 10 - 100 compared to an estimate based on the optical depth at the base of the atmosphere; instead, the rate of momentum transfer from a driving radiation field of luminosity L to the gas is roughly L/c multiplied by one plus half the optical depth evaluated using the photospheric temperature, which is far smaller than the optical depth one would obtain using the interior temperature. When we apply our results to conditions appropriate to ULIRGs and star clusters, we find that the asymptotic wind momentum flux from such objects should not significantly exceed that carried by the direct radiation field, L/c. This result constrains the expected mass loss rates from systems that exceed the Eddington limit to be of order the so-called "single-scattering" limit, and not significantly higher. We present an approximate fitting formula for the rate of momentum transfer from radiation to dusty gas through which it passes, which is suitable for implementation in sub-grid models of galaxy formation. Finally, we provide a first map of the column density distribution of gas in a radiatively-driven wind as a function of velocity, and velocity dispersion.Comment: 19 pages, 17 figures, MNRAS in press; some additional discussion compared to previous version, no changes in conclusion

Opioid stimulation in the ventral tegmental area facilitates the onset of maternal behavior in rats

This research investigated the effect of an increase or decrease in opioid activity in the ventral tegmental area (VTA) on the onset of maternal behavior in rats. In Experiment 1, the latency to show maternal behavior toward foster rat pups (sensitization latency) was determined in maternally naive female rats given either nothing or a unilateral intra-VTA injection of morphine sulfate (MS) (0.0, 0.01, 0.03, 0.1 or 0.3 µg), on the first three days of a 10-day period of constant exposure to pups. Rats treated with 0.03 µg MS had significantly shorter sensitization latencies than did rats treated with 0.0 µg MS, 0.01 µg MS, or receiving no treatment (higher doses of morphine produced intermediate results). The facilitating effect of intra-VTA MS on the onset of maternal behavior was blocked by pretreatment with naltrexone hydrochloride and was found to have a specific site of action in the VTA (MS injections dorsal to the VTA were ineffective). In Experiment 2, sensitization latencies were determined in periparturitional rats given a bilateral intra-VTA injection of either the opioid antagonist naltrexone methobromide (quaternary naltrexone), its vehicle, a sham injection, or left untreated 40 min after delivery of the last pup. The mothers' own pups were removed at delivery; mothers were nonmaternal at the time of testing. Quaternary naltrexone treatment produced significantly slower sensitization to foster pups than did control conditions. Total activity and pup-directed activity did not differ significantly with treatment. The results demonstrate that increased opioid activity in the VTA facilitates the onset of maternal behavior in inexperienced nonpregnant female rats, and decreased opioid activity in the VTA disrupts the rapid onset of maternal behavior at parturition

The new paradigm in Europe: is Goldilocks going global?

European Union ; Labor market ; Technology ; Productivity

Will electricity deregulation push inflation lower?

Deregulation of electricity generation will offer consumers many advantages, including dramatically lower energy costs. From a macroeconomic viewpoint, electricity purchases are interesting because they are a major component of consumers’ budgets (and thus of the CPI) and a large factor of production for many companies. This raises the possibility that electricity deregulation could create a substantial shock to the overall price trend, comparable to other recent energy shocks. The benefits to consumers and producers identified in this article strongly support legislative efforts to increase competition in one of the last strongholds of regulated profits.Electric utilities ; Inflation (Finance)