545 research outputs found
Dynamics of quantum entanglement in the reservoir with memory effects
The non-Markovian dynamics of quantum entanglement is studied by the
Shabani-Lidar master equation when one of entangled quantum systems is coupled
to a local reservoir with memory effects. The completely positive reduced
dynamical map can be constructed in the Kraus representation. Quantum
entanglement decays more slowly in the non-Markovian environment. The
decoherence time for quantum entanglement can be markedly increased by the
change of the memory kernel. It is found out that the entanglement sudden death
between quantum systems and entanglement sudden birth between the system and
reservoir occur at different instants.Comment: 14 pages, 3 figure
Gauge Theories on a 2+2 Anisotropic Lattice
The implementation of gauge theories on a four-dimensional anisotropic
lattice with two distinct lattice spacings is discussed, with special attention
to the case where two axes are finely and two axes are coarsely discretized.
Feynman rules for the Wilson gauge action are derived and the renormalizability
of the theory and the recovery of the continuum limit are analyzed. The
calculation of the gluon propagator and the restoration of Lorentz invariance
in on-shell states is presented to one-loop order in lattice perturbation
theory for on both 2+2 and 3+1 lattices.Comment: 27 pages, uses feynmf. Font compatibility adjuste
Patient experiences of anxiety, depression and acute pain after surgery: a longitudinal perspective
This study sought to explore the impact of the psychological variables anxiety and depression, on pain experience over time following surgery. Eighty-five women having major gynaecological surgery were assessed for anxiety, depression and pain after surgery. To gain further understanding, 37 patients participated in a semi-structured taped telephone interview 4–6 weeks post-operatively.
Pre-operative anxiety was found to be predictive of post-operative anxiety on Day 2, with patients who experienced high levels of anxiety before surgery continuing to feel anxious afterwards. By Day 4 both anxiety and depression scores increased as pain increased and one-third of the sample experienced levels of anxiety in psychiatric proportions whilst under one-third experienced similar levels of depression.
These findings have significant implications for the provision of acute pain management after surgery. Future research and those managing acute pain services need to consider the multidimensional effect of acute pain and the interface between primary and secondary care
Glial activation involvement in neuronal death by Japanese encephalitis virus infection
Japanese encephalitis is characterized by profound neuronal destruction/dysfunction and concomitant microgliosis/astrogliosis. Although substantial activation of glia is observed in Japanese encephalitis virus (JEV)-induced Japanese encephalitis, the inflammatory responses and consequences of astrocytes and microglial activation after JEV infection are not fully understood. In this study, infection of cultured neurons/glia with JEV caused neuronal death and glial activation, as evidenced by morphological transformation, increased cell proliferation and elevated tumour necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, IL-6 and RANTES (regulated upon activation, normal T-cell expressed and secreted) production. Replication-competent JEV caused all glial responses and neurotoxicity. However, replication-incompetent JEV lost these abilities, except for the ability to change microglial morphology. The bystander damage caused by activated glia also contributed to JEV-associated neurotoxicity. Microglia underwent morphological changes, increased cell proliferation and elevated TNF-alpha, IL-1 beta, IL-6 and RANTES expression in response to JEV infection. In contrast, IL-6 and RANTES expression, but no apparent morphological changes, proliferation or TNF-alpha/IL-1 beta expression, was demonstrated in JEV-infected astrocytes. Supernatants of JEV-infected microglia, but not JEV-infected astrocytes, induced glial activation and triggered neuronal death. Antibody neutralization studies revealed that TNF-alpha and IL-1 beta, but not RANTES or IL-6, released by activated microglia appeared to play roles in JEV-associated neurotoxicity. In conclusion, following JEV infection, neuronal death was accompanied by concomitant microgliosis and astrogliosis, and neurotoxic mediators released by JEV-activated microglia, rather than by JEV-activated astrocytes, had the ability to amplify the microglial response and cause neuronal death
Holographic dark energy in a universe with spatial curvature and massive neutrinos: a full Markov Chain Monte Carlo exploration
In this paper, we report the results of constraining the holographic dark
energy model with spatial curvature and massive neutrinos, based on a Markov
Chain Monte Carlo global fit technique. The cosmic observational data include
the full WMAP 7-yr temperature and polarization data, the type Ia supernova
data from Union2.1 sample, the baryon acoustic oscillation data from SDSS DR7
and WiggleZ Dark Energy Survey, and the latest measurements of from HST.
To deal with the perturbations of dark energy, we adopt the parameterized
post-Friedmann method. We find that, for the simplest holographic dark energy
model without spatial curvature and massive neutrinos, the phenomenological
parameter at more than confidence level. The inclusion of
spatial curvature enlarges the error bars and leads to only in about
range; in contrast, the inclusion of massive neutrinos does not
have significant influence on . We also find that, for the holographic dark
energy model with spatial curvature but without massive neutrinos, the
error bars of the current fractional curvature density
are still in order of ; for the model with massive neutrinos but
without spatial curvature, the upper bound of the total mass of
neutrinos is eV. Moreover, there exists clear degeneracy
between spatial curvature and massive neutrinos in the holographic dark energy
model, which enlarges the upper bound of by more than 2 times.
In addition, we demonstrate that, making use of the full WMAP data can give
better constraints on the holographic dark energy model, compared with the case
using the WMAP ``distance priors''.Comment: 21 pages, 10 figures; major revision; new figures and discussions
added; accepted by JCA
Identification and phylogenetic analysis of orf virus from goats in Taiwan
An outbreak of contagious ecthyma in goats in central Taiwan was investigated. The disease was diagnosed by physical and histopathologic examinations, and the etiology of the disease was identified as orf virus by electron microscopy and polymerase chain reaction (PCR) and sequence of major envelope protein (B2L) gene. The entire protein-coding region of B2L gene were cloned and sequenced. Phylogenetic analysis of B2L amino acid sequences showed that the orf virus identified in this outbreak was closer to the Indian ORFV-Mukteswar 59/05 isolate. This is the first report on the molecular characterization of orf virus in Taiwan
Association between Nephrotoxic Drug Combinations and Acute Kidney Injury in the Neonatal Intensive Care Unit
Objective: To determine the incidence of acute kidney injury (AKI) in infants exposed to nephrotoxic drug combinations admitted to 268 neonatal intensive care units managed by the Pediatrix Medical Group. Study design: We included infants born at 22-36 weeks gestational age, ≤120 days postnatal age, exposed to nephrotoxic drug combinations, with serum creatinine measurements available, and discharged between 2007 and 2016. To identify risk factors associated with a serum creatinine definition of AKI based on the Kidney Disease: Improving Global Outcomes criteria, we performed multivariable logistic and Cox regression adjusting for gestational age, sex, birth weight, postnatal age, race/ethnicity, sepsis, respiratory distress syndrome, baseline serum creatinine, and duration of combination drug exposure. The adjusted odds of AKI were determined relative to gentamicin + indomethacin for the following nephrotoxic drug combinations: chlorothiazide + ibuprofen; chlorothiazide + indomethacin; furosemide + gentamicin; furosemide + ibuprofen; furosemide + tobramycin; ibuprofen + spironolactone; and vancomycin + piperacillin-tazobactam. Results: Among 8286 included infants, 1384 (17%) experienced AKI. On multivariable analysis, sepsis, lower baseline creatinine, and duration of combination therapy were associated with increased odds of AKI. Furosemide + tobramycin and vancomycin + piperacillin-tazobactam were associated with a decreased risk of AKI relative to gentamicin + indomethacin in both the multivariable and Cox regression models. Conclusions: In this cohort, infants receiving longer durations of nephrotoxic combination therapy had an increased odds of developing AKI
Mutations in the Salmonella enterica serovar Choleraesuis cAMP-receptor protein gene lead to functional defects in the SPI-1 Type III secretion system
Salmonella enterica serovar Choleraesuis (Salmonella Choleraesuis) causes a lethal systemic infection (salmonellosis) in swine. Live attenuated Salmonella Choleraesuis vaccines are effective in preventing the disease, and isolates of Salmonella Choleraesuis with mutations in the cAMP-receptor protein (CRP) gene (Salmonella Choleraesuis Delta crp) are the most widely used, although the basis of the attenuation remains unclear. The objective of this study was to determine if the attenuated phenotype of Salmonella Choleraesuis Delta crp was due to alterations in susceptibility to gastrointestinal factors such as pH and bile salts, ability to colonize or invade the intestine, or cytotoxicity for macrophages. Compared with the parental strain, the survival rate of Salmonella Choleraesuis Delta crp at low pH or in the presence of bile salts was higher, while the ability of the mutant to invade intestinal epithelia was significantly decreased. In examining the role of CRP on the secretory function of the Salmonella pathogenicity island 1 (SPI-1) encoded type III secretion system (T3SS), it was shown that Salmonella Choleraesuis Delta crp was unable to secrete the SPI-1 T3SS effector proteins, SopB and SipB, which play a role in Salmonella intestinal invasiveness and macrophage cytotoxicity, respectively. In addition, caspase-1 dependent cytotoxicity for macrophages was significantly reduced in Salmonella Choleraesuis Delta crp. Collectively, this study demonstrates that the CRP affects the secretory function of SPI-1 T3SS and the resulting ability to invade the host intestinal epithelium, which is a critical element in the pathogenesis of Salmonella Choleraesuis
Modeling infection risk and energy use of upper-room Ultraviolet Germicidal Irradiation systems in multi-room environments
The effectiveness of ultraviolet irradiation at inactivating airborne pathogens is well proven, and the technology is also commonly promoted as an energy-efficient way of reducing infection risk in comparison to increasing ventilation. However, determining how and where to apply upper-room Ultraviolet Germicidal Irradiation devices for the greatest benefit is still poorly understood. This article links multi-zone infection risk models with energy calculations to assess the potential impact of a Ultraviolet Germicidal Irradiation installation across a series of inter-connected spaces, such as a hospital ward. A first-order decay model of ultraviolet inactivation is coupled with a room air model to simulate patient room and whole-ward level disinfection under different mixing and ultraviolet field conditions. Steady-state computation of quanta-concentrations is applied to the Wells–Riley equation to predict likely infection rates. Simulation of a hypothetical ward demonstrates the relative influence of different design factors for susceptible patients co-located with an infectious source or in nearby rooms. In each case, energy requirements are calculated and compared to achieving the same level of infection risk through improved ventilation. Ultraviolet devices are seen to be most effective where they are located close to the infectious source; however, when the location of the infectious source is not known, locating devices in patient rooms is likely to be more effective than installing them in connecting corridor or communal zones. Results show an ultraviolet system may be an energy-efficient solution to controlling airborne infection, particularly in semi-open hospital environments, and considering the whole ward rather than just a single room at the design stage is likely to lead to a more robust solution
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