Spin systems with dimerized ground states

In view of the numerous examples in the literature it is attempted to outline a theory of Heisenberg spin systems possessing dimerized ground states (``DGS systems") which comprises all known examples. Whereas classical DGS systems can be completely characterized, it was only possible to provide necessary or sufficient conditions for the quantum case. First, for all DGS systems the interaction between the dimers must be balanced in a certain sense. Moreover, one can identify four special classes of DGS systems: (i) Uniform pyramids, (ii) systems close to isolated dimer systems, (iii) classical DGS systems, and (iv), in the case of $s=1/2$, systems of two dimers satisfying four inequalities. Geometrically, the set of all DGS systems may be visualized as a convex cone in the linear space of all exchange constants. Hence one can generate new examples of DGS systems by positive linear combinations of examples from the above four classes.Comment: With corrections of proposition 4 and other minor change

Policy initiatives and firms' access to external finance: Evidence from a panel of emerging Asian economies

This paper analyses the impact of policy initiatives co-ordinated by Asian national governments on firms' composition of external finance. Using a unique firm-level database of eight Asian countries- Hong Kong SAR, Indonesia, Korea, Malaysia, Philippines, Singapore, Taiwan and Thailand over the period of 1996–2012 and a difference-in-differences approach, the results show a significant response of the debt composition to the policy change. We find that firms increased their uptake of long-term debt, while decreased their short-term debt. We also document that less risky and more profitable firms are more significantly affected by the policy change than riskier and less profitable firms. Finally, we show that the improved access to external finance after the policy initiative helped firms to raise their investment spending

Case Study on a New Alternate Charge Material for Electric Arc Furnace

Steel production through the electric arc furnace contributes nearly 30% of the total world steel production. To-day, this process is well established as an energy efficient economic process. The likely share of steel production through the electric are furnace route is projected to go up to around 40% of the world steel production, by the turn of this century. Till the seventies, steel scrap has traditionally been used as a main metallic source, as it has certain advantages such as low power consumption,low slag volume, less wear in the refractory lining, besides smooth furnace operation. However, the presence of tramp elements in scrap has shortcomings in producing quality steel products. Besides the quality aspects, the phenomenal rise in steel production through the EAF and increasing adoption of continuous casting have had a great impact on the availability and cost of steel scrap

एकीकृत चावल-चिंगट-पख मछली पालन द्वारा परंपरागत पोक्काली चावल खेती का पुनर्नवीकरण

Rejuvenation of the traditional Pokkali farming system through integrated paddy – shrimp – Fin fish farmin

A case report of recurrent spontaneous coronary artery dissection and Takotsubo cardiomyopathy: a treatment dilemma

Background: Spontaneous coronary artery dissection (SCAD) is an uncommon cause of acute coronary syndrome in younger females with no pre-existing history of coronary artery disease. Recurrent SCAD is common after a first episode and can involve the same coronary artery or present as a new dissection unrelated to the initial lesion. Current recommendations advise for a conservative approach in the absence of haemodynamic compromise and flow limitations. Conversely, there are no clear guidelines for the management of early recurrent SCAD. Case summary: A 52-year-old woman with history of obesity, asthma, and prediabetes presented with chest pain and electrocardiogram (ECG) showing inferior wall ST-elevation myocardial infarction (STEMI). Coronary angiography revealed proximal right coronary artery (RCA) dissection and distal left anterior descending artery (LAD) dissection, while left ventriculogram showed Takotsubo cardiomyopathy (TC). Angiography revealed no flow limitations so conservative management was pursued. She returned within a couple of days with recurrent chest pain and ECG showing similar findings of inferior STEMI. Repeat angiography confirmed progression of the proximal RCA SCAD with resolution of distal LAD SCAD. Since flow through the distal RCA was still preserved, conservative medical management was continued. She presented a third time for palpitations only and another repeat coronary angiogram showed healing RCA SCAD. Discussion: Management of early recurrent SCAD continues to be a clinical dilemma. In addition, our patient had features of TC which shares a similar clinical risk factor profile with SCAD thus it may be prudent to further investigate for TC in patients presenting with SCAD and have suggestive features of TC on history and echocardiography

Two-color pulse compounds in waveguides with a zero-nonlinearity point

We study incoherently coupled two-frequency pulse compounds in waveguides with single zero-dispersion and zero-nonlinearity points. In such waveguides, supported by a negative nonlinearity, soliton dynamics can be obtained even in domains of normal dispersion. We demonstrate trapping of weak pulses by solitary-wave wells, forming nonlinear-photonics meta-atoms, and molecule-like bound-states of pulses. We study the impact of Raman effect on these pulse compounds, finding that, depending on the precise subpulse configuration, they decelerate, accelerate, or are completely unaffected. Our results extend the range of systems in which two-frequency pulse compounds can be expected to exist and demonstrate further unique and unexpected behavior

Separation-dependent localization in a two-impurity spin-boson model

Using a variational approach we investigate the delocalized to localized crossover in the ground state of an Ohmic two-impurity spin-boson model, describing two otherwise non-interacting spins coupled to a common bosonic environment. We show that a competition between an environment-induced Ising spin interaction and externally applied fields leads to variations in the system-bath coupling strength, $\alpha_c$, at which the delocalized-localized crossover occurs. Specifically, the crossover regime lies between $\alpha_c=0.5$ and $\alpha_c=1$ depending upon the spin separation and the strength of the transverse tunneling field. This is in contrast to the analogous single spin case, for which the crossover occurs (in the scaling limit) at fixed $\alpha_c\approx1$. We also discuss links between the two-impurity spin-boson model and a dissipative two-spin transverse Ising model, showing that the latter possesses the same qualitative features as the Ising strength is varied. Finally, we show that signatures of the crossover may be observed in single impurity observables, as well as in the behaviour of the system-environment entanglement.Comment: 12 pages, 9 figures. Published version. Expanded discussion of the distance dependence between the impurities, and added a related figur

Probing of local ferroelectricity in BiFeO3 thin films and (BiFeO3)m(SrTiO3)m superlattices

Ferroelectric BiFeO3 thin films and artificial superlattices of (BiFeO3)m(SrTiO3)m (m~ 1 to 10 unit cells) were fabricated on (001)-oriented SrTiO3 substrates by pulsed laser ablation. The variation of leakage current and macroscopic polarization with periodicity was studied. Piezo force microscopy studies revealed the presence of large ferroelectric domains in the case of BiFeO3 thin films while a size reduction in ferroelectric domains was observed in the case of superlattice structures. The results show that the modification of ferroelectric domains through superlattice, could provide an additional control on engineering the domain wall mediated functional properties.Comment: 14 pages, To be published in J. Mag. Mag Mater. proceedings of EMRS 200

Proteome phenotypes discriminate the growing location and malting traits in Field-Grown Barley

Barley is one of the key cereal grains for malting and brewing industries. However, climate variability and unprecedented weather events can impact barley yield and end-product quality. The genetic background and environmental conditions are key factors in defining the barley proteome content and malting characteristics. Here, we measure the barley proteome and malting characteristics of three barley lines grown in Western Australia, differing in genetic background and growing location, by applying liquid chromatography–mass spectrometry (LC–MS). Using data-dependent acquisition LC–MS, 1571 proteins were detected with high confidence. Quantitative data acquired using sequential window acquisition of all theoretical (SWATH) MS on barley samples resulted in quantitation of 920 proteins. Multivariate analyses revealed that the barley lines’ genetics and their growing locations are strongly correlated between proteins and desired traits such as the malt yield. Linking meteorological data with proteomic measurements revealed how high-temperature stress in northern regions affects seed temperature tolerance during malting, resulting in a higher malt yield. Our results show the impact of environmental conditions on the barley proteome and malt characteristics; these findings have the potential to expedite breeding programs and malt quality prediction