Many-Impurity Effects in Fourier Transform Scanning Tunneling Spectroscopy

Fourier transform scanning tunneling spectroscopy (FTSTS) is a useful technique for extracting details of the momentum-resolved electronic band structure from inhomogeneities in the local density of states due to disorder-related quasiparticle scattering. To a large extent, current understanding of FTSTS is based on models of Friedel oscillations near isolated impurities. Here, a framework for understanding many-impurity effects is developed based on a systematic treatment of the variance Delta rho^2(q,omega) of the Fourier transformed local density of states rho(q,\omega). One important consequence of this work is a demonstration that the poor signal-to-noise ratio inherent in rho(q,omega) due to randomness in impurity positions can be eliminated by configuration averaging Delta rho^2(q,omega). Furthermore, we develop a diagrammatic perturbation theory for Delta rho^2(q,omega) and show that an important bulk quantity, the mean-free-path, can be extracted from FTSTS experiments.Comment: 7 pages, 5 figures. A version of the paper with high resolution, colour figures is available at http://www.trentu.ca/physics/batkinson/FTSTS.ps.gz minor revisions in response to refree report + figure 5 is modifie

Surface pinning of fluctuating charge order: an "extraordinary" surface phase transition

We study the mean-field theory of charge-density wave (CDW) order in a layered system, including the effect of the long-range Coulomb interaction and of screening by uncondensed electrons. We particularly focus on the conditions necessary for an ``extraordinary'' transition, in which the surface orders at a higher temperature, and is more likely to be commensurate, than the bulk. We interpret recent experiments on NaCCOC as indicating the presence of commensurate CDW at the surface that is not present in the bulk. More generally, we show that poor screening of the Coulomb interaction tends to stabilize incommensurate order, possibly explaining why the CDW order in LSCO and NbSe2 remains incommensurate to T -> 0, despite the small magnitude of the incommensurability.Comment: 9 pages, no figures, 31 references; 1 new figure and minor editing of the tex

Fluctuating Asymmetry of Measurable Parameters in Rana arvalis : Methodology

72 Fluctuating asymmetry (FA), i.e., undirected deviations from bilateral symmetry, of both measurable and nonmeasurable characteristics reflects ontogenetic instability, which some authors believe increases in response to genomic or environmental stress. This allows FA to be used for estimating the state of anthropogenically affected natural populations (e.g., Rana arvalis young of the year were captured on August 4 and 5, 2003, in the Kalinovskie Razrezy Park Forest in northern Yekaterinburg ( n = 26) and near the Yuzhnaya Bus Terminal ( n = 15), respectively. Ponds existing in the park forest had resulted from flooding desolate quarries. The vegetation was a herb-grass pine forest containing small shrubs. The results of our hydrochemical analyses performed in 2003 indicate that, according to the ecological sanitary classification of the quality of surface waters suggested by We measured the size parameters of the body that are standard for amphibians The results of the measurements shown in the table indicate that storage in the fixative led to a slight decrease in the mean values of most parameters measured in frogs from both populations. This decrease was the largest (and statistically significant) for the lengths of the thigh, crus, and temporal spot, i.e., the measurements at least partly involving soft tissue (F = 11.13-144.32, d.f. = 1/25 or 1/14, P = 0.004-0.0001 for the results of ANOVA with factors individual, body side

STM/STS Study on 4a X 4a Electronic Charge Order of Superconducting Bi2Sr2CaCu2O8+d

We performed low-bias STM measurements on underdoped Bi2212 crystals, and confirmed that a two-dimensional (2D) superstructure with a periodicity of four lattice constants (4a) is formed within the Cu-O plane at T<Tc. This 4a X 4a superstructure, oriented along the Cu-O bonding direction, is nondispersive and more intense in lightly doped samples with a zero temperature pseudogap (ZTPG) than in samples with a d-wave gap. The nondispersive 4a X 4a superstructure was clearly observed within the ZTPG or d-wave gap, while it tended to fade out outside the gaps. The present results provide a useful test for various models proposed for an electronic order hidden in the underdoped region of high-Tc cuprates.Comment: 4 pages, submitted to J. Phys. Soc. Jp

PECULIARITIES OF TERRITORIAL DISTRIBUTION OF TICK-BORNE ENCEPHALITIS MORBIDITY WITHIN IRKUTSK RESIDENTS

Irkutsk residents are infected, with, tick-borne encephalitis (TBE) mainly in Pribaykalie (Irkutsk region and Buryat Republic). TBE foci are rather various on this territory. Differences in some parameters of morbidity structure at the infection in different areas of this territory are reviewed, in this article

The Current State of Natural Foci of Tick-Borne Encephalitis near Irkutsk City

Among main factors that influence intensity of tick-borne encephalitis foci one can distinguish the numbers of core vector (here, taiga tick Ixodes persulcatus) and the percentage of infected ticks. This paper shows the results of five-year monitoring of the tick-borne encephalitis focus, which is situated near Irkutsk city. Detected are the variations in numbers and infestation of the core vector of tick-borne encephalitis, both spatial and temporal. Cause-effect connection between these factors and human TBE morbidity is not found. However, morbidity rates of the Irkutsk population, observed on the annual basis, bear evidence of high activity and intensity of the foci. In this regard, a number of preventive measures is put forward, but further observations concerning all the parameters that influence foci activity are required

Application of amperometric immunoenzyme sensors to the determination of bacterial antigens

A new version of immunoenzyme assay for the antigens of pathogenic microorganisms Streptococcus pyogenes and Staphylococcus aureus based on the use of amperometric sensors is proposed for their determination in diagnosing infectious diseases (tonsillitis of different severities). The best conditions for sensor operation were chosen, and the quantitative characteristics of the antibodies used and the antigen-antibody immune complexes formed. The sensors developed were tested with blood serums from ill patients, and the possibility of the differential diagnostics of diseases, at the early stages of their development, in particular, was demonstrated

Fleas (Siphonaptera) of small mammals in the northern taiga of Western Siberia

The purpose of the research is to identify the composition of fleas, and infection rates in small mammals in the northern taiga of Western Siberia; and to summarize information on fleas in the studied area. Materials and methods. In 2008, 2010, and 2016–2021, records of small mammals and their ectoparasites (fleas) were made in the northern taiga of Western Siberia. Parasitological survey was performed for 1363 specimens of insectivores and rodents of 13 species that were recorded using trap trenches, drift fences and trap-lines. A total of 1524 fleas of 18 species were recorded. Indices widely accepted in parasitology were used to assess quantitative indicators of fleas. Results and discussion. Based on the results of our own research and literature sources, small mammals in the northern taiga of Western Siberia were found to have specimens of 28 flea species. The flea fauna of the study area was represented by shrew fleas (Corrodopsylla birulai, Palaeopsylla sorecis), bird fleas (Ceratophyllus gallinae, C. garei), and specific species (Ceratophyllus anisus, C. indages, C. sciurorum, Megabothris walkeri, Leptopsylla segnis). Peromyscopsylla silvatica, Corrodopsylla birulai, Megabothris rectangulatus, Amalaraeus penicilliger, and Amphipsylla sibirica comprise the backbone of the flea fauna of small mammals in the northern taiga of Western Siberia