Whitepaper on Super-weakly Interacting Massive Particles for Snowmass 2013

Super-weakly interacting massive particles produced in the late decays of weakly interacting massive particles (WIMPs) are generic in large regions of supersymmetric parameter space and other frameworks for physics beyond the standard model. If their masses are similar to that of the decaying WIMP, then they could naturally account for all of the cosmological dark matter abundance. Their astrophysical consequences and collider signatures are distinct and different from WIMP candidates. In particular, they could modify Big Bang Nucleosynthesis, distort the Cosmic Microwave Background, reduce galactic substructure and lower central densities of low-mass galaxies.Comment: 4 pages, 2 figures, white paper for Snowmass 201

CARE1, a TY3-gypsy long terminal repeat retrotransposon in the food legume chickpea (Cicer arietinum L)

We report a novel Ty3-gypsy long terminal repeat retrotransposon CARE1 (_Cicer arietinum_ retro-element 1) in chickpea. This 5920-bp AT-rich (63%) element carries 723-bp 5' and 897-bp 3' LTRs respectively flanking an internal region of 4300-bp. The LTRs of CARE1 show 93.9% nucleotide identity to each other and have 4-bp (ACTA) terminal inverted repeats. A 17-bp potential tRNAmet primer binding site downstream to 5' LTR and a 13-bp polypurine tract upstream to 3' LTR have been identified. The order of domains (Gag-proteinase-reverse transcriptase-RNaseH-integrase) in the deduced amino acid sequence and phylogenetic tree constructed using reverse transcriptase sequences places CARE1 in the gypsy group of retrotransposons. Homologues of a number of _cis_-elements including CCAAT, TATA and GT-1 have been detected in the regulatory region or the 5' LTR of CARE1. Transgenic tobacco plants containing 5' LTR:GUS construct show that its 5'-LTR is inactive in a heterologous system under normal as well as tissue culture conditions. Genomic Southern blot experiments using 5’LTR of the element as a probe show that CARE1 or its related elements are present in the genomes of various chickpea accessions from various geographic regions

Enhanced modeling features within TREETOPS

The original motivation for TREETOPS was to build a generic multi-body simulation and remove the burden of writing multi-body equations from the engineers. The motivation of the enhancement was twofold: (1) to extend the menu of built-in features (sensors, actuators, constraints, etc.) that did not require user code; and (2) to extend the control system design capabilities by linking with other government funded software (NASTRAN and MATLAB). These enhancements also serve to bridge the gap between structures and control groups. It is common on large space programs for the structures groups to build hi-fidelity models of the structure using NASTRAN and for the controls group to build lower order models because they lack the tools to incorporate the former into their analysis. Now the controls engineers can accept the hi-fidelity NASTRAN models into TREETOPS, add sensors and actuators, perform model reduction and couple the result directly into MATLAB to perform their design. The controller can then be imported directly into TREETOPS for non-linear, time-history simulation

An Efficient Analytical Solution to Thwart DDoS Attacks in Public Domain

In this paper, an analytical model for DDoS attacks detection is proposed, in which propagation of abrupt traffic changes inside public domain is monitored to detect a wide range of DDoS attacks. Although, various statistical measures can be used to construct profile of the traffic normally seen in the network to identify anomalies whenever traffic goes out of profile, we have selected volume and flow measure. Consideration of varying tolerance factors make proposed detection system scalable to the varying network conditions and attack loads in real time. NS-2 network simulator on Linux platform is used as simulation testbed. Simulation results show that our proposed solution gives a drastic improvement in terms of detection rate and false positive rate. However, the mammoth volume generated by DDoS attacks pose the biggest challenge in terms of memory and computational overheads as far as monitoring and analysis of traffic at single point connecting victim is concerned. To address this problem, a distributed cooperative technique is proposed that distributes memory and computational overheads to all edge routers for detecting a wide range of DDoS attacks at early stage.Comment: arXiv admin note: substantial text overlap with arXiv:1203.240

Bond percolation of polymers

We study bond percolation of $N$ non-interacting Gaussian polymers of $\ell$ segments on a 2D square lattice of size $L$ with reflecting boundaries. Through simulations, we find the fraction of configurations displaying {\em no} connected cluster which span from one edge to the opposite edge. From this fraction, we define a critical segment density $\rho_{c}^L(\ell)$ and the associated critical fraction of occupied bonds $p_{c}^L(\ell)$, so that they can be identified as the percolation threshold in the $L \to \infty$ limit. Whereas $p_{c}^L(\ell)$ is found to decrease monotonically with $\ell$ for a wide range of polymer lengths, $\rho_{c}^L(\ell)$ is non-monotonic. We give physical arguments for this intriguing behavior in terms of the competing effects of multiple bond occupancies and polymerization.Comment: 4 pages with 6 figure

Atomic Compton profiles within different exchange-only theories

The Impulse Compton Profiles (CP's) J(q) and the - expectation values for some inert gas atoms (He-Kr) are computed and compared within the Harbola-Sahni (HS), Hartree-Fock(HF) theories and a Self Interaction Corrected (SIC) density functional model. The Compton profiles for excited states of Helium atom are also calculated. While the calculated CP's are found to generally agree, they differ slightly from one another for small values of the Compton parameter q and are in good agreement for large q values. The expectation values within the three theories are also found to be comparable. The HS formalism seem to mimic HF reasonably well in the momentum space, establishing the logical consistency of the former.Comment: 15 page