Dissipate locally, couple globally: a sharp transition from decoupling to infinite range coupling in Josephson arrays with on-site dissipation

We study the T=0 normal to superconducting transition of Josephson arrays with {\it on-site} dissipation. A perturbative renormalization group solution is given. Like the previously studied case of {\it bond} dissipation (BD), this is a "floating" to coupled (FC) phase transition. {\it Unlike} the BD transition, at which {\it only} nearest-neighbor couplings become relevant, here {\it all} inter-grain couplings, out to {\it infinitely} large distances, do so simultaneously. We predict, for the first time in an FC transition, a diverging spatial correlation length. Our results show the robustness of floating phases in dissipative quantum systems.Comment: 7+ pages, 3 eps figures, Europhysics Letters preprint format, as publishe

Internal waves in marginally stable abyssal stratified flows

The problem on internal waves in a weakly stratified two-layer fluid is studied semi-analytically. We discuss the 2.5-layer fluid flows with exponential stratification of both layers. The long-wave model describing travelling waves is constructed by means of a scaling procedure with a small Boussinesq parameter. It is demonstrated that solitary-wave regimes can be affected by the Kelvin–Helmholtz instability arising due to interfacial velocity shear in upstream flow.</p

Visualizing the Formation of the Kondo Lattice and the Hidden Order in URu2Si2

Heavy electronic states originating from the f atomic orbitals underlie a rich variety of quantum phases of matter. We use atomic scale imaging and spectroscopy with the scanning tunneling microscope (STM) to examine the novel electronic states that emerge from the uranium f states in URu2Si2. We find that as the temperature is lowered, partial screening of the f electrons' spins gives rise to a spatially modulated Kondo-Fano resonance that is maximal between the surface U atoms. At T=17.5 K, URu2Si2 is known to undergo a 2nd order phase transition from the Kondo lattice state into a phase with a hidden order parameter. From tunneling spectroscopy, we identify a spatially modulated, bias-asymmetric energy gap with a mean-field temperature dependence that develops in the hidden order state. Spectroscopic imaging further reveals a spatial correlation between the hidden order gap and the Kondo resonance, suggesting that the two phenomena involve the same electronic states

Elucidation of the Origin of nOes or rOes That Show the Hydration in the Minor and Major Grooves of DNA duplex with ATTAAT tract by a Combination of NOESY and ROESY Experiments

Abstract. A combination of NOESY and ROESY experiments (using ammonia as a catalyst across the pH range of 5 to 8.6) has given us a clear understanding regarding the origin of nOes that are attributed to the stereochemical location and the residence time of water in the major and the minor grooves of d 5&apos; ( 1 C 2 C 3 A 4 T 5 T 6 A 7 A 8 T 9 G 10 G) 2 3&apos; duplex Our conclusions are the following: (i) In the major groove, the presence of ammonia in the buffer does not influence on the process of exchange between bound and bulk water. (ii) It has been found that the observation of the bound water in the minor groove is a result of straight dipole-dipole effect at the physiological pH. (iii) The residence time of water near H2 of adenine (H2A) in the minor groove has been estimated to be in the range of 0.3 -0.5ns, which is closer to the residence time of the bound water found on the surface of protein. (iv) The hydration pattern in the minor groove in the physiological pH, under our NMR measurement condition, is similar to the ones found in the X-ray structure. (v) It has been shown that at pH &gt; 8.0 the nOe/rOe intensities of the water-H2A crosspeaks dramatically increase due to dipole-dipole and/or relayed magnetization transfer from H2A to water through ammonia catalyst. The nuclear Overhauser effect based NMR experiments have proved to be sensitive and efficient tool to identify sequentially assigned protein and DNA/RNA protons that have nOe/rOe interactions with nearby water protons [1

Multifaceted contributions : health workers and smallpox eradication in India

Smallpox eradication in South Asia was a result of the efforts of many grades of health-workers. Working from within the confines of international organisations and government structures, the role of the field officials, who were of various nationalities and also drawn from the cities and rural enclaves of the countries in these regions, was crucial to the development and deployment of policies. However, the role of these personnel is often downplayed in official histories and academic histories, which highlight instead the roles played by a handful of senior officials within the World Health Organization and the federal governments in the sub-continent. This article attempts to provide a more rounded assessment of the complex situation in the field. In this regard, an effort is made to underline the great usefulness of the operational flexibility displayed by field officers, wherein lessons learnt in the field were made an integral part of deploying local campaigns; careful engagement with the communities being targeted, as well as the employment of short term workers from amongst them, was an important feature of this work

Revealing reaction intermediates in one-carbon elongation by thiamine diphosphate/CoA-dependent enzyme family

2-Hydroxyacyl-CoA lyase/synthase (HACL/S) is a thiamine diphosphate (ThDP)-dependent versatile enzyme originally discovered in the mammalian α-oxidation pathway. HACL/S natively cleaves 2-hydroxyacyl-CoAs and, in its reverse direction, condenses formyl-CoA with aldehydes or ketones. The one-carbon elongation biochemistry based on HACL/S has enabled the use of molecules derived from greenhouse gases as biomanufacturing feedstocks. We investigated several HACL/S family members with high activity in the condensation of formyl-CoA and aldehydes, and distinct chain-length specificities and kinetic parameters. Our analysis revealed the structures of enzymes in complex with acyl-CoA substrates and products, several covalent intermediates, bound ThDP and ADP, as well as the C-terminal active site region. One of these observed states corresponds to the intermediary α–carbanion with hydroxymethyl-CoA covalently attached to ThDP. This research distinguishes HACL/S from related sub-families and identifies key residues involved in substrate binding and catalysis. These findings expand our knowledge of acyloin-condensation biochemistry and offer attractive prospects for biocatalysis using carbon elongation

How Kondo Holes Create Intense Nanoscale Heavy-Fermion Hybridization Disorder

Replacing a magnetic atom by a spinless atom in a heavy fermion compound generates a quantum state often referred to as a 'Kondo-hole'. No experimental imaging has been achieved of the atomic-scale electronic structure of a Kondo-hole, or of their destructive impact (Lawrence JM, et al. (1996) Kondo hole behavior in Ce0. 97La0. 03Pd3. Phys Rev B 53:12559-12562; Bauer ED, et al. (2011) Electronic inhomogeneity in a Kondo lattice. Proc Natl Acad Sci. 108:6857-6861) on the hybridization process between conduction and localized electrons which generates the heavy fermion state. Here we report visualization of the electronic structure at Kondo-holes created by substituting spinless Thorium atoms for magnetic Uranium atoms in the heavy-fermion system URu2Si2. At each Thorium atom, an electronic bound state is observed. Moreover, surrounding each Thorium atom we find the unusual modulations of hybridization strength recently predicted to occur at Kondo-holes (Figgins J, Morr DK (2011) Defects in heavy-fermion materials: unveiling strong correlations in real space. Phys Rev Lett 107:066401). Then, by introducing the 'hybridization gapmap' technique to heavy fermion studies, we discover intense nanoscale heterogeneity of hybridization due to a combination of the randomness of Kondo-hole sites and the long-range nature of the hybridization oscillations. These observations provide direct insight into both the microscopic processes of heavy-fermion forming hybridization and the macroscopic effects of Kondo-hole doping.Comment: Main Article + Figures, Supporting Information + Figures; PNAS 201