Luring BRCA1 to the Scene of the Crime

To preserve genome stability, BRCA1 must be recruited to sites of DNA damage, where BRCA1 facilitates repair of double-strand DNA breaks (DSBs). In this issue of Cancer Cell, Li and Yu report that BRCA1 recruitment involves a novel interaction between its partner protein BARD1 and poly(ADP-ribose) chains at the DSB

Threshold queueing describes the fundamental diagram of uninterrupted traffic

Queueing due to congestion is an important aspect of road traffic. This paper provides a brief overview of queueing models for traffic and a novel threshold queue that captures the main aspects of the empirical shape of the fundamental diagram. Our numerical results characterises the sources of variation that influence the shape of the fundamental diagram

Detection of SUSY in the Stau-Neutralino Coannihilation Region at the LHC

We study the feasibility of detecting the stau neutralino (stau_1-neutralino_1)coannihilation region at the LHC using tau leptons. The signal is characterized by multiple low energy tau leptons from neutralino_2-->tau stau_1-->tau tau neutralino_1 decays, where the stau_1 and neutralino_1 mass difference (Delta M) is constrained to be 5-15 GeV by current experimental bounds including the bound on the amount of neutralino cold dark matter. Within the framework of minimal supergravity models, we show that if hadronically decaying tau's can be identified with 50% efficiency for visible pt >20 GeV the observation of such signals is possible in the final state of two tau leptons plus large missing energy and two jets. With a gluino mass of 830 GeV the signal can be observed with as few as 3-10 fb^-1 of data (depending on the size of Delta M). Using a mass measurement of the tau pairs with 10 fb^-1 we can determine dM with a statistical uncertainty of 12% for Delta M = 10 GeV and an additional systematic uncertainty of 14% if the gluino mass has an uncertainty of 5%.Comment: 15 pages. 9 Figures, Latex, Typing error in the title as it appeared in the web listing is corrected, paper is unchange

Runway Extension With a Vegetated mechanically Stabilized Earth Wall (VMSEW)

In this session we discuss the extension of the existing Runway 2-20 at the Paoli Municipal Airport, which sits on top of an approximately 70-foot embankment. Alternatives were analyzed to identify the most cost-effective solution, which was determined to be the construction of a vegetated mechanically stabilized earth wall (VMSEW). To date we have completed one phase of construction (approximately 30 feet of wall)

The Stau Neutralino Co-annihilation Region at an International Linear Collider

We probe the stau-neutralino co-annihilation domain of the parameter space allowed by the current experimental bounds on the light Higgs mass, the b-> s \gamma decay, and the amount of neutralino cold dark matter within the framework of minimal SUGRA models at a 500 GeV e+e- linear collider. The most favorable signals of SUSY are stau pair production and neutralino pair production where the small mass difference between the lighter stau and the lightest neutralino in the co-annihilation region is ~5-15 GeV and hence generates low-energy tau leptons in the final state. This small mass difference would be a striking signal of many SUGRA models. We find that a calorimeter covering down to 1^o from the beams is crucial to reduce the two-photon background and the mass difference could be measured at a level of 10% with 500 fb^-1 of data where an invariant mass of two-tau jets and missing energy is used as a discriminator.Comment: 17 pages, 7 figure

A model for dark current characterization and simulation

The Poisson and Normal probability distributions poorly match the dark current histogram of a typical image sensor. The histogram has only positive values, and is positively skewed (with a long tail). The Normal distribution is symmetric (and possesses negative values), while the Poisson distribution is discrete. Image sensor characterization and simulation would benefit from a different distribution function, which matches the experimental observations better. Dark current fixed pattern noise is caused by discrete randomly-distributed charge generation centers. If these centers shared a common charge-generation rate, and were distributed uniformly, the Poisson distribution would result. The fact that it does not indicates that the generation rates vary, a spatially non-uniform amplification is applied to the centers, or that the spatial distribution of centers is non-uniform. Monte Carlo simulations have been used to examine these hypotheses. The Log-Normal, Gamma and Inverse Gamma distributions have been evaluated as empirical models for characterization and simulation. These models can accurately match the histograms of specific image sensors. They can also be used to synthesize the dark current images required in the development of image processing algorithms. Simulation methods can be used to create synthetic images with more complicated distributions