Algebraic Quantum Error-Correction Codes

Based on the group structure of a unitary Lie algebra, a scheme is provided to systematically and exhaustively generate quantum error correction codes, including the additive and nonadditive codes. The syndromes in the process of error-correction distinguished by different orthogonal vector subspaces, the coset subspaces. Moreover, the generated codes can be classified into four types with respect to the spinors in the unitary Lie algebra and a chosen initial quantum state

Managing voiding dysfunction in young men

AbstractVoiding dysfunction is an uncommon condition in young men. With increased understanding of the etiology of chronic lower urinary tract dysfunction, there has been significant improvement in the management of the condition. We have reviewed the current literature and make suggestions about diagnosis, treatment, and further research on this topic. We searched the PubMed database for the management of voiding dysfunction in young men using the following terms: voiding dysfunction, lower urinary tract symptoms, young men, risk factor, urodynamics study, uroflowmetry, magnetic resonance imaging, primary bladder neck obstruction/bladder neck dysfunction, dysfunctional voiding/pseudodyssynergia, impaired detrusor contractility/detrusor underactivity, adrenergic antagonist, transurethral incision, urotherapy, baclofen, and botulinum toxin. Uroflowmetry is an important noninvasive examination for screening young men for possible voiding dysfunction. A videourodynamic study is recommended for patients with low urine flow. Primary bladder neck obstruction and dysfunctional voiding are the two most common diagnoses. α-Adrenergic antagonists and urotherapy are widely used for treating bladder neck obstruction and dysfunctional voiding, respectively. Botulinum toxin A may become a potential therapeutic option in the future. Although the published reports usually included a small number of patients and lacked randomization and a placebo-controlled group, these clinical studies still provide great advances in managing voiding dysfunction in young men. Further well-designed studies are warranted to support optimal management of these conditions

Employee business at various levels of a hierarchy for organisations completing case work

This article describes a model for examining the contribution of supervisors to an organization by considering the case work they complete as a production system. The average delay in case work is referred to as the service level. At a given service level, the minimization of total wages within one hour can be studied as a cost function. With this cost function, wage spending on handled-case time and idle time can be formulated. The ratio between the handled-case time and idle time of all employees at the kth level within 1 hour is defined as the‘ busy index’ at the kth level. From the optimal hierarchical structure, we find the following two properties: (1) Given any two levels i and j, the ratio between the idle times of ith and jth levels is independent not only of the service level but also the rate of arriving cases; and (2) At each level, the busy indices are proportional to the square root of each level’s wage rates. This implies that the busy indices decrease with the hierarchical level. Ultimately, when the wage rates at all levels are equal, the increment also becomes equal

THE INFLUENCE OF TAI-CHI EXERCISE ON DYNAMICS OF LOWER EXTREMITY FOR THE ELDERLY DURING SIT-TO-STAND

The purpose of this study was to investigate the influence of Tai Chi exercise on sit-tostand in the elderly. Ten healthy female elders (normal group) and nine healthy Tai-Chi female practitioner (Tai-Chi group) participated in this study. The results indicated: (1) During the forward flexion phase, normal group showed significantly greater hip flexion angle and moment than Tai-Chi group (

Non-Markovian finite-temperature two-time correlation functions of system operators: beyond the quantum regression theorem

An extremely useful evolution equation that allows systematically calculating the two-time correlation functions (CF's) of system operators for non-Markovian open (dissipative) quantum systems is derived. The derivation is based on perturbative quantum master equation approach, so non-Markovian open quantum system models that are not exactly solvable can use our derived evolution equation to easily obtain their two-time CF's of system operators, valid to second order in the system-environment interaction. Since the form and nature of the Hamiltonian are not specified in our derived evolution equation, our evolution equation is applicable for bosonic and/or fermionic environments and can be applied to a wide range of system-environment models with any factorized (separable) system-environment initial states (pure or mixed). When applied to a general model of a system coupled to a finite-temperature bosonic environment with a system coupling operator L in the system-environment interaction Hamiltonian, the resultant evolution equation is valid for both L = L^+ and L \neq L^+ cases, in contrast to those evolution equations valid only for L = L^+ case in the literature. The derived equation that generalizes the quantum regression theorem (QRT) to the non-Markovian case will have broad applications in many different branches of physics. We then give conditions on which the QRT holds in the weak system-environment coupling case, and apply the derived evolution equation to a problem of a two-level system (atom) coupled to a finite-temperature bosonic environment (electromagnetic fields) with L \neq L^+.Comment: To appear in the Journal of Chemical Physics (12 pages, 1 figure