Experimental observation of Dirac-like surface states and topological phase transition in Pb1−x_{1-x}Snx_xTe(111) films

The surface of a topological crystalline insulator (TCI) carries an even number of Dirac cones protected by crystalline symmetry. We epitaxially grew high quality Pb$_{1-x}$Sn$_x$Te(111) films and investigated the TCI phase by in-situ angle-resolved photoemission spectroscopy. Pb$_{1-x}$Sn$_x$Te(111) films undergo a topological phase transition from trivial insulator to TCI via increasing the Sn/Pb ratio, accompanied by a crossover from n-type to p-type doping. In addition, a hybridization gap is opened in the surface states when the thickness of film is reduced to the two-dimensional limit. The work demonstrates an approach to manipulating the topological properties of TCI, which is of importance for future fundamental research and applications based on TCI

Macroeconomic Implications of Capital Inflows in India

The study attempts to analyse the behaviour of some macroeconomic variables in response to total capital inflows in India using quarterly data for the period 1994Q1-2007Q4. Time trend of all variables except nominal effective exchange rate-both export and trade based and current account balance shows instability over the period of study. Current account balance is the only variable which is stationary in level form all other variables are stationary in first difference form. Cointegration test confirms the long run equilibrium relation between total capital inflows (TCI) and real effective exchange rate-both trade based and export based and between TCI and nominal effective exchange rate-export based. Granger causality test confirms the bidirectional causality between real effective exchange rate-export based and TCI and between foreign exchange reserve & TCI and unidirectional causality from TCI to real effective exchange rate-trade based.International Capital Inflows, Time Series Econometrics

An Evaluation of Changes in the Bioclimate of Łódź in the Light of the Tourism Climate Index

The paper presents basic information concerning bioclimatic conditions in Łódź based on the Tourism Climate Index (TCI). The index makes it possible to assess in a comprehensive manner, based on specified meteorological parameters, the climatic conditions affecting the development of tourism. The study uses measurements from the weather station, Łódź-Lublinek, taken in the years 1966-2014. The TCI values have a distinct annual pattern with the highest values recorded in summer. The summer season has the highest frequency of days with ‘very good’ or ‘excellent’ conditions for tourism. An assessment of the variability of bioclimatic conditions indicates an increase in the number of days with high TCI values pointing to ‘very good’ or ‘excellent’ conditions for tourism and recreation

Chagas disease reactivation in a heart transplant patient infected by domestic Trypanosoma cruzi discrete typing unit I (TcIDOM)

Background Trypanosoma cruzi, causative agent of Chagas disease, displays high intraspecific genetic diversity: six genetic lineages or discrete typing units (DTUs) are currently recognized, termed TcI through TcVI. Each DTU presents a particular distribution pattern across the Americas, and is loosely associated with different transmission cycles and hosts. Several DTUs are known to circulate in Central America. It has been previously suggested that TcI infection is benign and does not lead to chronic chagasic cardiomyopathy (CCC). Findings In this study, we genotyped T. cruzi parasites circulating in the blood and from explanted cardiac tissue of an El Salvadorian patient who developed reactivation Chagas disease while on immunosuppressive medications after undergoing heart transplant in the U.S. as treatment for end-stage CCC. Parasite typing was performed through molecular methods (restriction fragment length polymorphism of polymerase reaction chain amplified products, microsatellite typing, maxicircle sequence typing and low-stringency single primer PCR, [LSSP-PCR]) as well as lineage-specific serology. We show that the parasites infecting the patient belong to the TcI DTU exclusively. Our data indicate that the parasites isolated from the patient belong to a genotype frequently associated with human infection throughout the Americas (TcI DOM ). Conclusions Our results constitute compelling evidence in support of TcI DTU’s ability to cause end-stage CCC and help dispel any residual bias that infection with this lineage is benign, pointing to the need for increased surveillance for dissemination of this genotype in endemic regions, the USA and globally

Rock-salt SnS and SnSe: Native Topological Crystalline Insulators

Unlike time-reversal topological insulators, surface metallic states with Dirac cone dispersion in the recently discovered topological crystalline insulators (TCIs) are protected by crystal symmetry. To date, TCI behaviors have been observed in SnTe and the related alloys Pb$_{1-x}$Sn$_{x}$Se/Te, which incorporate heavy elements with large spin-orbit coupling (SOC). Here, by combining first-principles and {\it ab initio} tight-binding calculations, we report the formation of a TCI in the relatively lighter rock-salt SnS and SnSe. This TCI is characterized by an even number of Dirac cones at the high-symmetry (001), (110) and (111) surfaces, which are protected by the reflection symmetry with respect to the ($\bar{1}$10) mirror plane. We find that both SnS and SnSe have an intrinsically inverted band structure and the SOC is necessary only to open the bulk band gap. The bulk band gap evolution upon volume expansion reveals a topological transition from an ambient pressure TCI to a topologically trivial insulator. Our results indicate that the SOC alone is not sufficient to drive the topological transition.Comment: 5 pages, 5 figure

Topological Crystalline Insulator Nanomembrane with Strain-Tunable Band Gap

The ability to fine-tune band gap and band inversion in topological materials is highly desirable for the development of novel functional devices. Here we propose that the electronic properties of a free-standing nanomembrane of topological crystalline insulator (TCI) SnTe and Pb$_{1-x}$Sn$_x$(Se,Te) are highly tunable by engineering elastic strain and controlling membrane thickness, resulting in tunable band gap and giant piezoconductivity. Membrane thickness governs the hybridization of topological electronic states on opposite surfaces, while elastic strain can further modulate the hybridization strength by controlling the penetration length of surface states. We propose a frequency-resolved infrared photodetector using force-concentration induced inhomogeneous elastic strain in TCI nanomembrane with spatially varying width. The predicted tunable band gap accompanied by strong spin-textured electronic states will open up new avenues for fabricating piezoresistive devices, thermoelectrics, infrared detectors and energy-efficient electronic and optoelectronic devices based on TCI nanomembrane.Comment: 10 pages, 9 figure

Alternative treatments in the control of psoroptic mange in a flock of organic production sheep.

Abstract The aim of the experiment was to verify the efficacy of the treatment of psoroptic mange in a flock of Churra sheep farmed under organic production conditions, using alternative methods. One group, C Control (N=9), was given no treatment, a second group, TAH Antihomotoxic (N=10), was intramuscularly administered an antihomotoxic preparation every two days, thus receiving a total of seven injections over a two-week period. The third group, TCI Citronella (N=10), was topically administered a 1% solution of 50%essential Citronella Java oil and 50% Potassium Soap twice daily, in each milking, during the two-week period. A fourth group, TCIT Citronella+Thymol (N=10), was topically administered Citronella with 1% mother tincture of Thymol to boost the acaricide activity. The results obtained were analysed by ANOVA for scores and improvement of lesions. At the end of the experiment, TCI and TCIT showed significantly fewer lesions (P<0.05) than the control group and TAH, no differences being detected between the latter two groups. Improvement was significantly higher (P<0.05) in TCI (45%) and TCTT (48%) in comparison with the control group,which only showed 3% improvement. TAH improved by 30% (P<0.05) in comparison with the control group. There were no significant differences between TCI and TCIT. In conclusion, treatment with essential Citronella Java oil and potassium soap can be used as an alternative to conventional methods to control psoroptic mange