A road to reality with topological superconductors

Topological states of matter are a source of low-energy quasiparticles, bound to a defect or propagating along the surface. In a superconductor these are Majorana fermions, described by a real rather than a complex wave function. The absence of complex phase factors promises protection against decoherence in quantum computations based on topological superconductivity. This is a tutorial style introduction written for a Nature Physics focus issue on topological matter.Comment: pre-copy-editing, author-produced version of the published paper: 4 pages, 2 figure

Effects of lower limb amputation on the mental rotation of feet

What happens to the mental representation of our body when the actual anatomy of our body changes? We asked 18 able-bodied controls, 18 patients with a lower limb amputation and a patient with rotationplasty to perform a laterality judgment task. They were shown illustrations of feet in different orientations which they had to classify as left or right limb. This laterality recognition task, originally introduced by Parsons in Cognit Psychol 19:178–241, (1987), is known to elicit implicit mental rotation of the subject’s own body part. However, it can also be solved by mental transformation of the visual stimuli. Despite the anatomical changes in the body periphery of the amputees and of the rotationplasty patient, no differences in their ability to identify illustrations of their affected versus contralateral limb were found, while the group of able-bodied controls showed clear laterality effects. These findings are discussed in the context of various strategies for mental rotation versus the maintenance of an intact prototypical body structural description

CRP polymorphisms and chronic kidney disease in the third national health and nutrition examination survey

<p>Abstract</p> <p>Background</p> <p><it>CRP </it>gene polymorphisms are associated with serum C-reactive protein concentrations and may play a role in chronic kidney disease (CKD) progression. We recently reported an association between the gene variant rs2808630 and CKD progression in African Americans with hypertensive kidney disease. This association has not been studied in other ethnic groups.</p> <p>Methods</p> <p>We used data from 5955 participants from Phase 2 of The Third National Health and Nutrition Examination Survey (1991-1994) to study the association between <it>CRP </it>polymorphisms and CKD prevalence in a population-based sample. The primary outcome was CKD defined as estimated glomerular filtration rate (eGFR) <60 ml/min or the presence of albuminuria. Secondary outcomes were the presence of albuminuria (any degree) and continuous eGFR. Six single nucleotide polymorphisms (SNPs) from the <it>CRP </it>gene, rs2808630, rs1205, rs3093066, rs1417938, rs3093058, and rs1800947, were evaluated.</p> <p>Results</p> <p><it>CRP </it>rs2808630 AG compared to the referent AA genotype was associated with CKD in non-Hispanic blacks (n = 1649, 293 of whom had CKD) with an adjusted odds ratio (OR) of 3.09 (95% CI 1.65-5.8; p = 0.001). For the secondary outcomes, rs2808630 AG compared to the referent AA genotype was associated with albuminuria with an adjusted OR of 3.07 (95% CI 1.59-5.94; p = 0.002), however not with eGFR. There was no association between the SNPs and CKD, albuminuria or eGFR in non-Hispanic whites or Mexicans Americans.</p> <p>Conclusions</p> <p>In this cross-sectional study, the 3' flanking <it>CRP </it>gene variant rs2808630 was associated with CKD, mainly through its association with albuminuria in the non-Hispanic blacks. Despite not finding an association with eGFR, our results support our previous study demonstrating an association between <it>CRP </it>gene variant rs2808630 and CKD progression in a longitudinal cohort of African American with hypertensive kidney disease.</p

Fractional deuteration applied to biomolecular solid-state NMR spectroscopy

Solid-state Nuclear Magnetic Resonance can provide detailed insight into structural and dynamical aspects of complex biomolecules. With increasing molecular size, advanced approaches for spectral simplification and the detection of medium to long-range contacts become of critical relevance. We have analyzed the protonation pattern of a membrane-embedded ion channel that was obtained from bacterial expression using protonated precursors and D2O medium. We find an overall reduction of 50% in protein protonation. High levels of deuteration at Hα and Hβ positions reduce spectral congestion in (1H,13C,15N) correlation experiments and generate a transfer profile in longitudinal mixing schemes that can be tuned to specific resonance frequencies. At the same time, residual protons are predominantly found at amino-acid side-chain positions enhancing the prospects for obtaining side-chain resonance assignments and for detecting medium to long-range contacts. Fractional deuteration thus provides a powerful means to aid the structural analysis of complex biomolecules by solid-state NMR

Prevalence of Coxiella burnetii in clinically healthy German sheep flocks

<p>Abstract</p> <p>Background</p> <p>Current epidemiological data on the situation of <it>Coxiella (C.) burnetii </it>infections in sheep are missing, making risk assessment and the implementation of counteractive measures difficult. Using the German state of Thuringia as a model example, the estimated sero-, and antigen prevalence of <it>C. burnetii </it>(10% and 25%, respectively) was assessed at flock level in 39/252 randomly selected clinically healthy sheep flocks with more than 100 ewes and unknown abortion rate.</p> <p>Results</p> <p>The CHECKIT™ Q-fever Test Kit identified 11 (28%) antibody positive herds, whereas real-time PCR revealed the presence of <it>C. burnetii </it>DNA in 2 (5%) of the flocks. Multiple-locus variable number of tandem repeats analysis of 9 isolates obtained from one flock revealed identical profiles. All isolates contained the plasmid QpH1.</p> <p>Conclusions</p> <p>The results demonstrate that <it>C. burnetii </it>is present in clinically inconspicuous sheep flocks and sporadic flare-ups do occur as the notifications to the German animal disease reporting system show. Although <it>C. burnetii </it>infections are not a primary veterinary concern due to the lack of significant clinical impact on animal health (with the exception of goats), the eminent zoonotic risk for humans should not be underestimated. Therefore, strategies combining the interests of public and veterinary public health should include monitoring of flocks, the identification and culling of shedders as well as the administration of protective vaccines.</p

A method for dynamic subtraction MR imaging of the liver

BACKGROUND: Subtraction of Dynamic Contrast-Enhanced 3D Magnetic Resonance (DCE-MR) volumes can result in images that depict and accurately characterize a variety of liver lesions. However, the diagnostic utility of subtraction images depends on the extent of co-registration between non-enhanced and enhanced volumes. Movement of liver structures during acquisition must be corrected prior to subtraction. Currently available methods are computer intensive. We report a new method for the dynamic subtraction of MR liver images that does not require excessive computer time. METHODS: Nineteen consecutive patients (median age 45 years; range 37–67) were evaluated by VIBE T1-weighted sequences (TR 5.2 ms, TE 2.6 ms, flip angle 20°, slice thickness 1.5 mm) acquired before and 45s after contrast injection. Acquisition parameters were optimized for best portal system enhancement. Pre and post-contrast liver volumes were realigned using our 3D registration method which combines: (a) rigid 3D translation using maximization of normalized mutual information (NMI), and (b) fast 2D non-rigid registration which employs a complex discrete wavelet transform algorithm to maximize pixel phase correlation and perform multiresolution analysis. Registration performance was assessed quantitatively by NMI. RESULTS: The new registration procedure was able to realign liver structures in all 19 patients. NMI increased by about 8% after rigid registration (native vs. rigid registration 0.073 ± 0.031 vs. 0.078 ± 0.031, n.s., paired t-test) and by a further 23% (0.096 ± 0.035 vs. 0.078 ± 0.031, p < 0.001, paired t-test) after non-rigid realignment. The overall average NMI increase was 31%. CONCLUSION: This new method for realigning dynamic contrast-enhanced 3D MR volumes of liver leads to subtraction images that enhance diagnostic possibilities for liver lesions

Binary and Millisecond Pulsars at the New Millennium

We review the properties and applications of binary and millisecond pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1300. There are now 56 binary and millisecond pulsars in the Galactic disk and a further 47 in globular clusters. This review is concerned primarily with the results and spin-offs from these surveys which are of particular interest to the relativity community.Comment: 59 pages, 26 figures, 5 tables. Accepted for publication in Living Reviews in Relativity (http://www.livingreviews.org

Azimuthal anisotropy and correlations at large transverse momenta in p+pp+p and Au+Au collisions at sNN\sqrt{s_{_{NN}}}= 200 GeV

Results on high transverse momentum charged particle emission with respect to the reaction plane are presented for Au+Au collisions at $\sqrt{s_{_{NN}}}$= 200 GeV. Two- and four-particle correlations results are presented as well as a comparison of azimuthal correlations in Au+Au collisions to those in $p+p$ at the same energy. Elliptic anisotropy, $v_2$, is found to reach its maximum at $p_t \sim 3$ GeV/c, then decrease slowly and remain significant up to $p_t\approx 7$ -- 10 GeV/c. Stronger suppression is found in the back-to-back high-$p_t$ particle correlations for particles emitted out-of-plane compared to those emitted in-plane. The centrality dependence of $v_2$ at intermediate $p_t$ is compared to simple models based on jet quenching.Comment: 4 figures. Published version as PRL 93, 252301 (2004

Azimuthal anisotropy in Au+Au collisions at sqrtsNN = 200 GeV

The results from the STAR Collaboration on directed flow (v_1), elliptic flow (v_2), and the fourth harmonic (v_4) in the anisotropic azimuthal distribution of particles from Au+Au collisions at sqrtsNN = 200 GeV are summarized and compared with results from other experiments and theoretical models. Results for identified particles are presented and fit with a Blast Wave model. Different anisotropic flow analysis methods are compared and nonflow effects are extracted from the data. For v_2, scaling with the number of constituent quarks and parton coalescence is discussed. For v_4, scaling with v_2^2 and quark coalescence is discussed.Comment: 26 pages. As accepted by Phys. Rev. C. Text rearranged, figures modified, but data the same. However, in Fig. 35 the hydro calculations are corrected in this version. The data tables are available at http://www.star.bnl.gov/central/publications/ by searching for "flow" and then this pape