Measurement of the LCG2 and glite file catalogue's performance

When the Large Hadron Collider (LHC) begins operation at CERN in 2007 it will produce data in volumes never before seen. Physicists around the world will manage, distribute and analyse petabytes of this data using the middleware provided by the LHC Computing Grid. One of the critical factors in the smooth running of this system is the performance of the file catalogues which allow users to access their files with a logical filename without knowing their physical location. This paper presents a detailed study comparing the performance and respective merits and shortcomings of two of the main catalogues: the LCG File Catalogue and the gLite FiReMan catalogue

Entangled Coherent State Qubits in an Ion Trap

We show how entangled qubits can be encoded as entangled coherent states of two-dimensional centre-of-mass vibrational motion for two ions in an ion trap. The entangled qubit state is equivalent to the canonical Bell state, and we introduce a proposal for entanglement transfer from the two vibrational modes to the electronic states of the two ions in order for the Bell state to be detected by resonance fluorescence shelving methods.Comment: 4 pages, No figures, accepted to PRA, minor chang

Mormon Colonization Scheme for Vancouver Island

"The question of establishing colonies on Vancouver Island, being then under consideration by the British Government, it was thought that if the Latter-day Saints in Great Britain could go there, they might establish a colony or 'stake of Zion' and be under the immediate jurisdiction of the leaders of the church in America. On this account a petition for assistance from the British Government to this end was addressed to Her Majesty Queen Victoria and to every member of the British Parliament.

The role of HER1-HER4 and EGFRvIII in hormone-refractory prostate cancer

<b>Purpose</b>: The role of the type I receptor tyrosine kinase (HER) family in progression of prostate cancer is controversial. Breast cancer studies show that these receptors should be investigated as a family. The current study investigates expression of HER1-HER4 and EGFRvIII in matched hormone-sensitive and hormone-refractory prostate tumors. <b>Experimental Design</b>: Immunohistochemical analysis was used to investigate protein expression of HER1-HER4, EGFRvIII, and phosphorylated Akt (pAkt) in matched hormone-sensitive and hormone-refractory prostate tumors. <b>Results</b>: Surprisingly, high HER2 membrane expression in hormone-sensitive tumors was associated with an increased time to biochemical relapse (<i>P</i> = 0.0003), and this translated into longer overall survival (<i>P</i> = 0.0021). Consistent with other studies, HER4 membrane expression in hormone-sensitive tumors was associated with longer time to biochemical relapse (<i>P</i> = 0.042), and EGFRvIII membrane expression was associated with shorter time to biochemical relapse (<i>P</i> = 0.015). An increase in pAkt expression was associated with reduced survival (<i>P</i> = 0.0098). Multivariate analysis showed that HER2 was an independent positive predictive marker of time to relapse in hormone-sensitive prostate tumors (<i>P</i> = 0.014). In contrast, high HER2 expression in hormone-refractory tumors was associated with decreased time to death from biochemical relapse (<i>P</i> = 0.039), and EGFRvIII nuclear expression was associated with decreased time to death from biochemical relapse and decreased overall survival (<i>P</i> = 0.02 and <i>P</i> = 0.005). <b>Conclusion</b>: These results suggest that the HER family may have multiple roles in prostate cancer, and that expression of the proteins alone is insufficient to predict the biological response that they may elicit

Selection from read-only memory with limited workspace

Given an unordered array of $N$ elements drawn from a totally ordered set and an integer $k$ in the range from $1$ to $N$, in the classic selection problem the task is to find the $k$-th smallest element in the array. We study the complexity of this problem in the space-restricted random-access model: The input array is stored on read-only memory, and the algorithm has access to a limited amount of workspace. We prove that the linear-time prune-and-search algorithm---presented in most textbooks on algorithms---can be modified to use $\Theta(N)$ bits instead of $\Theta(N)$ words of extra space. Prior to our work, the best known algorithm by Frederickson could perform the task with $\Theta(N)$ bits of extra space in $O(N \lg^{*} N)$ time. Our result separates the space-restricted random-access model and the multi-pass streaming model, since we can surpass the $\Omega(N \lg^{*} N)$ lower bound known for the latter model. We also generalize our algorithm for the case when the size of the workspace is $\Theta(S)$ bits, where $\lg^3{N} \leq S \leq N$. The running time of our generalized algorithm is $O(N \lg^{*}(N/S) + N (\lg N) / \lg{} S)$, slightly improving over the $O(N \lg^{*}(N (\lg N)/S) + N (\lg N) / \lg{} S)$ bound of Frederickson's algorithm. To obtain the improvements mentioned above, we developed a new data structure, called the wavelet stack, that we use for repeated pruning. We expect the wavelet stack to be a useful tool in other applications as well.Comment: 16 pages, 1 figure, Preliminary version appeared in COCOON-201

Van der Waals Frictional Drag induced by Liquid Flow in Low- Dimensional Systems

We study the van der Waals frictional drag force induced by liquid flow in low-dimensional systems (2D and 1D electron systems, and 2D and 1D channels with liquid). We find that for both 1D and 2D systems, the frictional drag force induced by liquid flow may be several orders of magnitude larger than the frictional drag induced by electronic current.Comment: 10 pages, 4 figure