205 research outputs found
Bell's Inequality and Entanglement in Qubits
We propose an alternative evaluation of quantum entanglement by measuring the
maximum violation of the Bell's inequality without performing a partial trace
operation. This proposal is demonstrated by bridging the maximum violation of
the Bell's inequality and the concurrence of a pure state in an -qubit
system, in which one subsystem only contains one qubit and the state is a
linear combination of two product states. We apply this relation to the ground
states of four qubits in the Wen-Plaquette model and show that they are
maximally entangled. A topological entanglement entropy of the Wen-Plaquette
model could be obtained by relating the upper bound of the maximum violation of
the Bell's inequality to the concurrences of a pure state with respect to
different bipartitions.Comment: 10 page
An Improved Tax Scheme for Selfish Routing
We study the problem of routing traffic for independent selfish users in a congested network to minimize the total latency. The inefficiency of selfish routing motivates regulating the flow of the system to lower the total latency of the Nash Equilibrium by economic incentives or penalties. When applying tax to the routes, we follow the definition of [Christodoulou et al, Algorithmica, 2014] to define ePoA as the Nash total cost including tax in the taxed network over the optimal cost in the original network. We propose a simple tax scheme consisting of step functions imposed on the links. The tax scheme can be applied to routing games with parallel links, affine cost functions and single-commodity networks to lower the ePoA to at most 4/3 - epsilon, where epsilon only depends on the discrepancy between the links. We show that there exists a tax scheme in the two link case with an ePoA upperbound less than 1.192 which is almost tight. Moreover, we design another tax scheme that lowers ePoA down to 1.281 for routing games with groups of links such that links in the same group are similar to each other and groups are sufficiently different
Stationary Light Pulses in Cold Atomic Media
Stationary light pulses (SLPs), i.e., light pulses without motion, are formed
via the retrieval of stored probe pulses with two counter-propagating coupling
fields. We show that there exist non-negligible hybrid Raman excitations in
media of cold atoms that prohibit the SLP formation. We experimentally
demonstrate a method to suppress these Raman excitations and realize SLPs in
laser-cooled atoms. Our work opens the way to SLP studies in cold as well as in
stationary atoms and provides a new avenue to low-light-level nonlinear optics.Comment: 4 pages, 4 figure
Development and validation of the newly developed Preschool Theory of Mind Assessment (ToMA-P)
IntroductionTheory of mind (ToM) refers to the ability to understand and attribute mental states to oneself and others. A ToM measure is warranted for preschool children to assess their ToM development from a multidimensional perspective (i.e., cognitive and affective dimensions). This study aimed to develop the Preschool Theory of Mind Assessment (ToMA-P) and to evaluate its construct validity and applicability.MethodsThe ToMA-P was developed based on comprehensive literature review and revised with expert panel feedback. Its psychometric properties were evaluated in 205 typically developing preschoolers with Rasch analysis for its dimensionality, item difficulties, and convergent validity.ResultsThe results indicated that all ToMA-P items, except for one, fit the hypothesized two-dimensional construct. The item difficulties in the cognitive and affective dimensions followed developmental sequences. The ToMA-P scores exhibited good convergent validity, as evidenced by its significant correlations with age, verbal comprehension, adaptive functions, and daily ToM performance (p < 0.05). Children’s responses and behaviors also showed that the ToMA-P has good applicability.DiscussionThis study provides empirical evidence that the ToMA-P measures cognitive and affective ToM following developmental sequences, and that it has potential as a clinical tool for assessing ToM in preschool children
Pregnancy-induced hypertension is an independent risk factor for meconium aspiration syndrome: A retrospective population based cohort study
Objective: Meconium aspiration syndrome (MAS), possibly resulting from fetal hypoxia, is a respiratory distress disorder in the infant. Pregnancy-induced hypertension (PIH) can cause placental dysfunction and lead to fetal hypoxia, which may induce the development of MAS. Therefore, the aim of this study was to determine the association between PIH and MAS and to identify the predictive risk factors. Materials and methods: This was a retrospective cohort study. We selected patients with newly diagnosed PIH and a matched cohort group from the Taiwan National Health Insurance Research Database (NHIRD), from January 1, 2000 till December 31, 2013. For each patient in the PIH cohort, 4 subjects without PIH, matched for age and year of delivery, were randomly selected as the comparison cohort. The incidence of meconium aspiration syndrome was assessed in both groups. Results: Among the 23.3 million individuals registered in the NHIRD, 29,013 patients with PIH and 116,052 matched controls were identified. Patients who experienced PIH had a higher incidence of MAS than did those without PIH. According to a multivariate analysis, PIH (odds ratio [OR] = 1.70, 95% confidence interval [CI] = 1.49–1.93, p < 0.0001) was independently associated with increased risk of MAS. Additionally, age ≥30 years (OR = 1.26, 95% CI = 1.12–1.42, p = 0.0001), nulliparity (OR = 1.13, 95% CI = 1.01–1.27, p = 0.0367) and patients with diabetes mellitus (OR = 3.09, 95% CI = 1.35–7.09, p = 0.0078) were also independent risk factors of MAS. Conclusion: Patients with PIH obtained higher subsequent risk for the development of MAS than those without PIH. Besides, age ≥30 years, nulliparity and patients with diabetes mellitus are the independent risk factors of developing MAS. Keywords: Pregnancy-induced hypertension, Hypertension in pregnancy, Gestational hypertension, Preeclampsia, Meconium aspiration syndrom
- …