Fidelity susceptibility in the two-dimensional transverse field Ising and XXZ models

We study the fidelity susceptibility in the two-dimensional(2D) transverse field Ising model and the 2D XXZ model numerically. It is found that in both models, the fidelity susceptibility as a function of the driving parameter diverges at the critical points. The validity of the fidelity susceptibility to signal for the quantum phase transition is thus verified in these two models. We also compare the scaling behavior of the extremum of the fidelity susceptibility to that of the second derivative of the ground state energy. From those results, the theoretical argument that fidelity susceptibility is a more sensitive seeker for a second order quantum phase transition is also testified in the two models.Comment: 6 pages, 7 figure

Constitutive modeling of steel-polypropylene hybrid fiber reinforced concrete using a non-associated plasticity and its numerical implementation

This paper presents a non-associated plasticity-based constitutive model for hybrid steel–polypropylene fiber reinforced concrete (HFRC) materials in an attempt to characterize the stress–strain responses under multiaxial loading scenarios. Together with a five-parameter loading surface and uncoupled hardening and softening regimes, a nonlinear plastic potential function is particularly introduced into the constitutive model with the material constants experimentally determined through a true triaxial compression test, which allows a more accurate estimation of the volumetric dilatency of HFRC. The influence of fiber parameters on the plastic flow direction is also addressed. Furthermore, the developed model is implemented into ABAQUS finite element package through a User-defined Material (UMAT) subroutine that can be applicable for the convenient use in numerical simulation of HFRC materials. A substepping scheme with error control for integrating the elasto-plastic stress–strain rate equations is presented in detail. Subsequently, the proposed model is evaluated by available multiaxial compression test results of both plain concrete and FRC reported by other researchers. It is shown that the constitutive model can realistically capture the stress–strain responses as well as the volumetric deformation of HFRC having various fiber reinforcement indices

Tourism, jobs, capital accumulation and the economy: A dynamic analysis

This paper examines the effects of tourism on labor employment, capital accumulation and resident welfare for a small open economy with unemployment. A tourism boom improves the terms of trade, increases labor employment, but lowers capital accumulation. The reduction in the capital stock depends on the degree of factor intensity. When the traded sector is weakly capital intensive, the fall in capital would not be so severe and the expansion of tourism improves welfare. However, when the traded sector is strongly capital intensive, the fall in capital can be a dominant factor to lower welfare. This immiserizing result of tourism on resident welfare is confirmed by the German data.tourism ; employment ; capital accumulation ; welfare

Transport through a quantum ring, a dot and a barrier embedded in a nanowire in magnetic field

We investigate the transport through a quantum ring, a dot and a barrier embedded in a nanowire in a homogeneous perpendicular magnetic field. To be able to treat scattering potentials of finite extent in magnetic field we use a mixed momentum-coordinate representation to obtain an integral equation for the multiband scattering matrix. For a large embedded quantum ring we are able to obtain Aharanov-Bohm type of oscillations with superimposed narrow resonances caused by interaction with quasi-bound states in the ring. We also employ scattering matrix approach to calculate the conductance through a semi-extended barrier or well in the wire. The numerical implementations we resort to in order to describe the cases of weak and intermediate magnetic field allow us to produce high resolution maps of the ``near field'' scattering wave functions, which are used to shed light on the underlying scattering processes.Comment: RevTeX, 13 pages with included postscript figures, high resolution version available at http://hartree.raunvis.hi.is/~vidar/Rann/VG_04.pd

Chemoenzymatic elaboration of monosaccharides using engineered cytochrome P450_(BM3) demethylases

Polysaccharides comprise an extremely important class of biopolymers that play critical roles in a wide range of biological processes, but the synthesis of these compounds is challenging because of their complex structures. We have developed a chemoenzymatic method for regioselective deprotection of monosaccharide substrates using engineered Bacillus megaterium cytochrome P450 (P450_(BM3)) demethylases that provides a highly efficient means to access valuable intermediates, which can be converted to a wide range of substituted monosaccharides and polysaccharides. Demethylases displaying high levels of regioselectivity toward a number of protected monosaccharides were identified using a combination of protein and substrate engineering, suggesting that this approach ultimately could be used in the synthesis of a wide range of substituted mono- and polysaccharides for studies in chemistry, biology, and medicine

Applications of Anterior Segment Optical Coherence Tomography in Cornea and Ocular Surface Diseases

Optical coherence tomography (OCT) is a noncontact technology that produces high-resolution cross-sectional images of ocular tissues. Anterior segment OCT (AS-OCT) enables the precise visualization of anterior segment structure; thus, it can be used in various corneal and ocular surface disorders. In this review, the authors will discuss the application of AS-OCT for diagnosis and management of various corneal and ocular surface disorders. Use of AS-OCT for anterior segment surgery and postoperative management will also be discussed. In addition, application of the device for research using human data and animal models will be introduced

A Dynamic Analysis of Tied Aid

In this paper we examine the impact of tied aid on capital accumulation and welfare in the presence of a quota on imports. Using a simulation model we establish that tied aid can lower the relative domestic price of the manufactured good and therefore reduce the stock of capital. In the presence of a strong production externality from capital accumulation and high tying ratio, tied aid may immiserize the recipient country

The Bipolar II depression questionnaire:A self-report Tool for detecting Bipolar II depression

Bipolar II (BP-II) depression is often misdiagnosed as unipolar (UP) depression, resulting in suboptimal treatment. Tools for differentiating between these two types of depression are lacking. This study aimed to develop a simple, self-report screening instrument to help distinguish BP-II depression from UP depressive disorder. A prototype BP-II depression questionnaire (BPIIDQ-P) was constructed following a literature review, panel discussions and a field trial. Consecutively assessed patients with a diagnosis of depressive disorder or BP with depressive episodes completed the BPIIDQ-P at a psychiatric outpatient clinic in Hong Kong between October and December 2013. Data were analyzed using discriminant analysis and logistic regression. Of the 298 subjects recruited, 65 (21.8%) were males and 233 (78.2%) females. There were 112 (37.6%) subjects with BP depression [BP-I = 42 (14.1%), BP-II = 70 (23.5%)] and 182 (62.4%) with UP depression. Based on family history, age at onset, postpartum depression, episodic course, attacks of anxiety, hypersomnia, social phobia and agoraphobia, the 8-item BPIIDQ-8 was constructed. The BPIIDQ-8 differentiated subjects with BP-II from those with UP depression with a sensitivity/specificity of 0.75/0.63 for the whole sample and 0.77/0.72 for a female subgroup with a history of childbirth. The BPIIDQ-8 can differentiate BP-II from UP depression at the secondary care level with satisfactory to good reliability and validity. It has good potential as a screening tool for BP-II depression in primary care settings. Recall bias, the relatively small sample size, and the high proportion of females in the BP-II sample limit the generalization of the results

Preparation of GHZ states via Grover's quantum searching algorithm

In this paper we propose an approach to prepare GHZ states of an arbitrary multi-particle system in terms of Grover's fast quantum searching algorithm. This approach can be regarded as an extension of the Grover's algorithm to find one or more items in an unsorted database.Comment: 9 pages, Email address: [email protected]