‘Imposter participants’ in online qualitative research, a new and increasing threat to data integrity?

Letter to the Editor: Health Expectation

Canonical Decompositions of n-qubit Quantum Computations and Concurrence

The two-qubit canonical decomposition SU(4) = [SU(2) \otimes SU(2)] Delta [SU(2) \otimes SU(2)] writes any two-qubit quantum computation as a composition of a local unitary, a relative phasing of Bell states, and a second local unitary. Using Lie theory, we generalize this to an n-qubit decomposition, the concurrence canonical decomposition (C.C.D.) SU(2^n)=KAK. The group K fixes a bilinear form related to the concurrence, and in particular any computation in K preserves the tangle ||^2 for n even. Thus, the C.C.D. shows that any n-qubit quantum computation is a composition of a computation preserving this n-tangle, a computation in A which applies relative phases to a set of GHZ states, and a second computation which preserves it. As an application, we study the extent to which a large, random unitary may change concurrence. The result states that for a randomly chosen a in A within SU(2^{2p}), the probability that a carries a state of tangle 0 to a state of maximum tangle approaches 1 as the even number of qubits approaches infinity. Any v=k_1 a k_2 for such an a \in A has the same property. Finally, although ||^2 vanishes identically when the number of qubits is odd, we show that a more complicated C.C.D. still exists in which K is a symplectic group.Comment: v2 corrects odd qubit CCD misstatements, reference chapter for KAK v3 notation change to coincide with sequel, typos. 20 pages, 0 figure

The top 100 most cited manuscripts in bladder cancer: A bibliometric analysis (review article)

Background Bladder cancer is one of the top 10 frequently occurring neoplasms worldwide and is responsible for over 150,000 deaths per annum. Bibliometric analysis helps further our knowledge of bladder cancer research, topics and trends. It is useful to identify the most influential articles and its impact pertinent to this field that has helped mould our understanding and management of bladder cancer. Materials and methods Search terms related to bladder cancer were compiled and used to interrogate the Thompson Reuters Web of Science indexing database. The 100 most cited manuscripts in the English language were identified and further evaluated by theme, manuscript type, journal, year of publication, author and institution. Results The Web of Science search returned a total of 47,381 manuscripts. The median number of citations among the top 100 was 515, ranging from 2257 to 352. The greatest number of manuscripts in the top 100 were published in the Journal of Urology (n = 15), followed by the Journal of Clinical Oncology (n = 14) and European Urology (n = 13). The most cited paper (Stein et al. Journal of Clinical Oncology 2001, 2257 citations) reported on the long term outcomes from a large cohort of patients that underwent radical cystectomy and bilateral pelvic lymphadenectomy for transitional cell carcinoma. The most prevalent theme was the pathobiology of bladder cancer (n = 37) followed by oncological treatment (n = 17). The majority of manuscripts were of original research (n = 79) mainly based on basic science study design and published from institutions in the USA. Conclusion The pathobiology and oncological treatment of bladder cancer were the areas with most citations within the top 100. This bibliometric analysis has identified influential articles in the field on bladder cancer, which provides a useful guide to authors as to what type of article constitutes a highly citable publication in this subject

A homozygous ADAMTS2 nonsense mutation in a Doberman Pinscher dog with Ehlers Danlos syndrome and extreme skin fragility

An eight-week old Doberman Pinscher was diagnosed with Ehlers Danlos syndrome based on the dog's hyper-mobile carpal, tarsal and stifle joints and abnormal skin. The skin was loose and hyper-elastic with several wounds and large atrophic scars. The dog was euthanized after a severe degloving injury from minimal trauma. A whole-genome sequence, generated with DNA from the dog's blood, contained a rare, homozygous C-to-T transition at position 2408978 on chromosome 11. This transition is predicted to alter the ADAMTS2 transcript (ADAMTS2:c.769C>T) and encode a nonsense mutation (p.Arg257Ter). Biallelic ADAMTS2 mutations have caused a type of Ehlers Danlos syndrome known as dermatosparaxis in other species

Analysis of CP Violation in Neutralino Decays to Tau Sleptons

In the minimal supersymmetric standard model, tau sleptons $\tilde \tau_{1,2}$ and neutralinos $\tilde \chi^0_{1,2}$ are expected to be among the lightest supersymmetric particles that can be produced copiously at future $e^+e^-$ linear colliders. We analyze $\tilde \tau$ pair and $\tilde \chi_1^0 \tilde \chi_2^0$ production under the assumption $m_{\tilde \chi_1^0} < m_{\tilde \tau_1} < m_{\tilde \chi_2^0}$, allowing the relevant parameters of the SUSY Lagrangian to have complex phases. We show that the transverse and normal components of the polarization vector of the $\tau$ lepton produced in $\tilde \chi_2^0$ decays offer sensitive probes of these phases.Comment: LaTeX, 30 pages with 10 .eps figure

Dynamical effects of the nanometer-sized polarized domains in Pb(Zn1/3Nb2/3)O3

Recent neutron scattering measurements performed on the relaxor ferroelectric Pb[(Zn1/3Nb2/3)0.92Ti0.08]O3 (PZN-8%PT) in its cubic phase at 500 K, have revealed an anomalous ridge of inelastic scattering centered ~0.2 A-1 from the zone center (Gehring et al., Phys. Rev. Lett. 84, 5216 (2000)). This ridge of scattering resembles a waterfall when plotted as a phonon dispersion diagram, and extends vertically from the transverse acoustic (TA) branch near 4 meV to the transverse optic (TO) branch near 9 meV. No zone center optic mode was found. We report new results from an extensive neutron scattering study of pure PZN that exhibits the same waterfall feature. We are able to model the dynamics of the waterfall using a simple coupled-mode model that assumes a strongly q-dependent optic mode linewidth Gamma1(q) that increases sharply near 0.2 A-1 as one approaches the zone center. This model was motivated by the results of Burns and Dacol in 1983, who observed the formation of a randomly-oriented local polarization in PZN at temperatures far above its ferroelectric phase transition temperature. The dramatic increase in Gamma1 is believed to occur when the wavelength of the optic mode becomes comparable to the size of the small polarized micro-regions (PMR) associated with this randomly-oriented local polarization, with the consequence that longer wavelength optic modes cannot propagate and become overdamped. Below Tc=410 K, the intensity of the waterfall diminishes. At lowest temperatures ~30 K the waterfall is absent, and we observe the recovery of a zone center transverse optic mode near 10.5 meV.Comment: 8 pages, 9 figures (one color). Submitted to Physical Review

Confronting the Minimal Supersymmetric Standard Model with the Study of Scalar Leptons at Future Linear e+e- Colliders

Sleptons can easily be found at future linear e+e- colliders if kinematically accessible. Measurements of their masses and decay distributions would then determine MSSM parameters. This paper presents a detailed MC study of the production and decay of the lighter scalar tau lepton, stau1. We found that mstau1 and the left-right mixing angle of stau would be measured within an error of a few percent. tanbeta is determinable in some region of the parameter space through simultaneous studies of stau1-and selectron-pair production: the polarization measurement of the tau leptons from stau1 decays and the M1, mchi1 determination using selectron pair production and decay. We also point out the possibility to determine bino-selectron-e coupling through the measurement of the angular distribution of the selectron-pair production. The error on the coupling is expected to be comparable to its typical SUSY radiative correction, which is proportional to log(msquark/mslepton). The radiative correction affects M1 and tanbeta determination, necessitating the full 1-loop radiative correction to the selectron production processes. The implication of these measurements of the MSSM parameters on selecting models of the origin of supersymmetry breaking is also discussed.Comment: 35 pages. REVTEX(gzip compressed and uuencoded). Figure are not included. Text and 15 Figures are available at http://jlcux1.kek.jp/subg/susy/index-e.html#librar

Measuring our universe from galaxy redshift surveys

Galaxy redshift surveys have achieved significant progress over the last couple of decades. Those surveys tell us in the most straightforward way what our local universe looks like. While the galaxy distribution traces the bright side of the universe, detailed quantitative analyses of the data have even revealed the dark side of the universe dominated by non-baryonic dark matter as well as more mysterious dark energy (or Einstein's cosmological constant). We describe several methodologies of using galaxy redshift surveys as cosmological probes, and then summarize the recent results from the existing surveys. Finally we present our views on the future of redshift surveys in the era of Precision Cosmology.Comment: 82 pages, 31 figures, invited review article published in Living Reviews in Relativity, http://www.livingreviews.org/lrr-2004-

Phonon-mediated anisotropic superconductivity in the Y and Lu nickel borocarbides

We present scanning tunneling spectroscopy and microscopy measurements at low temperatures in the borocarbide materials RNi2B2C (R=Y, Lu). The characteristic strong coupling structure due to the pairing interaction is unambiguously resolved in the superconducting density of states. It is located at the superconducting gap plus the energy corresponding to a phonon mode identified in previous neutron scattering experiments. These measurements also show that this mode is coupled to the electrons through a highly anisotropic electron-phonon interaction originated by a nesting feature of the Fermi surface. Our experiments, from which we can extract a large electron-phonon coupling parameter lambda (between 0.5 and 0.8), demonstrate that this anisotropic electron-phonon coupling has an essential contribution to the pairing interaction. The tunneling spectra show an anisotropic s-wave superconducting gap function.Comment: 5 pages, 3 figure