Heavy-tailed distributions in fatal traffic accidents: role of human activities

Human activities can play a crucial role in the statistical properties of observables in many complex systems such as social, technological and economic systems. We demonstrate this by looking into the heavy-tailed distributions of observables in fatal plane and car accidents. Their origin is examined and can be understood as stochastic processes that are related to human activities. Simple mathematical models are proposed to illustrate such processes and compared with empirical results obtained from existing databanks.Comment: 10 pages, 5 figure

Cold Dark Matter Isocurvature Perturbations: Cosmological Constraints and Applications

In this paper we present the constraints on cold dark matter (CDM) isocurvature contributions to the cosmological perturbations. By employing Markov Chain Monte Carlo method (MCMC), we perform a global analysis for cosmological parameters using the latest astronomical data, such as 7-year Wilkinson Microwave Anisotropy Probe (WMAP7) observations, matter power spectrum from the Sloan Digital Sky Survey (SDSS) luminous red galaxies (LRG), and "Union2" type Ia Supernovae (SNIa) sample. We find that the correlated mixture of adiabatic and isocurvature modes are mildly better fitting to the current data than the pure adiabatic ones, with the minimal $\chi^2$ given by the likelihood analysis being reduced by 3.5. We also obtain a tight limit on the fraction of the CDM isocurvature contributions, which should be less than 14.6% at 95% confidence level. With the presence of the isocurvature modes, the adiabatic spectral index becomes slightly bigger, n_s^{\rm adi}=0.972\pm0.014~(1\,\sigma), and the tilt for isocurvature spectrum could be large, namely, the best fit value is n_s^{\rm iso}=3.020. Finally, we discuss the effect on WMAP normalization priors, shift parameter R, acoustic scale l_A and z_{*}, from the CDM isocurvaure perturbation. By fitting the mixed initial condition to the combined data, we find the mean values of R, l_A and z_{*} can be changed about 2.9\sigma, 2.8\sigma and 1.5\sigma respectively, comparing with those obtained in the pure adiabatic condition.Comment: 9 pages, 5 figures, 3 tables, references adde

DhhP, a Cyclic di-AMP Phosphodiesterase of Borrelia burgdorferi, Is Essential for Cell Growth and Virulence

Cyclic di-AMP (c-di-AMP) is a recently discovered second messenger in bacteria. Most of work on c-di-AMP signaling has been done in Gram-positive bacteria, firmicutes, and actinobacteria, where c-di-AMP signaling pathways affect potassium transport, cell wall structure, and antibiotic resistance. Little is known about c-di-AMP signaling in other bacteria. Borrelia burgdorferi, the causative agent of Lyme disease, is a spirochete that has a Gram-negative dual membrane. In this study, we demonstrated that B. burgdorferi BB0619, a DHH-DHHA1 domain protein (herein designated DhhP), functions as c-di-AMP phosphodiesterase. Recombinant DhhP hydrolyzed c-di-AMP to pApA in a Mn2+- or Mg2+-dependent manner. In contrast to c-di-AMP phosphodiesterases reported thus far, DhhP appears to be essential for B. burgdorferi growth both in vitro and in the mammalian host. Inactivation of the chromosomal dhhP gene could be achieved only in the presence of a plasmid-encoded inducible dhhP gene. The conditional dhhP mutant had a dramatic increase in intracellular c-di-AMP level in comparison to the isogenic wild-type strain. Unlike what has been observed in Gram-positive bacteria, elevated cellular c-di-AMP in B. burgdorferi did not result in an increased resistance to β-lactamase antibiotics, suggesting that c-di-AMP's functions in spirochetes differ from those in Gram-positive bacteria. In addition, the dhhP mutant was defective in induction of the σS factor, RpoS, and the RpoS-dependent outer membrane virulence factor OspC, which uncovers an important role of c-di-AMP in B. burgdorferi virulence

MHV Vertices and Scattering Amplitudes in Gauge Theory

The generic googly amplitudes in gauge theory are computed by using the Cachazo-Svrcek-Witten approach to perturbative calculation in gauge theory and the results are in agreement with the previously well-known ones. Within this approach we also discuss the parity transformation, charge conjugation and the dual Ward identity. We also extend this calculation to include fermions and the googly amplitudes with a single quark-anti-quark pair are obtained correctly from fermionic MHV vertices. At the end we briefly discuss the possible extension of this approach to gravity.Comment: Latex file, 38 pages, 15 figures; v2, minor changes, references added; v2, minor changes, 2 references adde

MHV Vertices and Fermionic Scattering Amplitudes in Gauge Theory with Quarks and Gluinos

The Cachazo-Svrcek-Witten approach to perturbative gauge theory is extended to gauge theories with quarks and gluinos. All googly amplitudes with quark-antiquark pairs and gluinos are computed and shown to agree with the previously known results. The computations of the non-MHV or non-googly amplitudes are also briefly discussed, in particular the purely fermionic amplitude with 3 quark-antiquark pairs.Comment: 41 pages, 21 figures; v2, minor changes, references added;v3, 2 important additions, references adde

Determinant representations of scalar products for the open XXZ chain with non-diagonal boundary terms

With the help of the F-basis provided by the Drinfeld twist or factorizing F-matrix for the open XXZ spin chain with non-diagonal boundary terms, we obtain the determinant representations of the scalar products of Bethe states of the model.Comment: Latex file, 28 pages, based on the talk given by W. -L. Yang at Statphys 24, Cairns, Australia, 19-23 July, 201

Health care systems in Sweden and China: Legal and formal organisational aspects

<p>Abstract</p> <p>Background</p> <p>Sharing knowledge and experience internationally can provide valuable information, and comparative research can make an important contribution to knowledge about health care and cost-effective use of resources. Descriptions of the organisation of health care in different countries can be found, but no studies have specifically compared the legal and formal organisational systems in Sweden and China.</p> <p>Aim</p> <p>To describe and compare health care in Sweden and China with regard to legislation, organisation, and finance.</p> <p>Methods</p> <p>Literature reviews were carried out in Sweden and China to identify literature published from 1985 to 2008 using the same keywords. References in recent studies were scrutinized, national legislation and regulations and government reports were searched, and textbooks were searched manually.</p> <p>Results</p> <p>The health care systems in Sweden and China show dissimilarities in legislation, organisation, and finance. In Sweden there is one national law concerning health care while in China the law includes the "Hygienic Common Law" and the "Fundamental Health Law" which is under development. There is a tendency towards market-orientated solutions in both countries. Sweden has a well-developed primary health care system while the primary health care system in China is still under development and relies predominantly on hospital-based care concentrated in cities.</p> <p>Conclusion</p> <p>Despite dissimilarities in health care systems, Sweden and China have similar basic assumptions, i.e. to combine managerial-organisational efficiency with the humanitarian-egalitarian goals of health care, and both strive to provide better care for all.</p

Global Gene Expression Associated with Hepatocarcinogenesis in Adult Male Mice Induced by in Utero Arsenic Exposure

Our previous work has shown that exposure to inorganic arsenic in utero produces hepatocellular carcinoma (HCC) in adult male mice. To explore further the molecular mechanisms of transplacental arsenic hepatocarcinogenesis, we conducted a second arsenic transplacental carcinogenesis study and used a genomewide microarray to profile arsenic-induced aberrant gene expression more extensively. Briefly, pregnant C3H mice were given drinking water containing 85 ppm arsenic as sodium arsenite or unaltered water from days 8 to 18 of gestation. The incidence of HCC in adult male offspring was increased 4-fold and tumor multiplicity 3-fold after transplacental arsenic exposure. Samples of normal liver and liver tumors were taken at autopsy for genomic analysis. Arsenic exposure in utero resulted in significant alterations (p < 0.001) in the expression of 2,010 genes in arsenic-exposed liver samples and in the expression of 2,540 genes in arsenic-induced HCC. Ingenuity Pathway Analysis revealed that significant alterations in gene expression occurred in a number of biological networks, and Myc plays a critical role in one of the primary networks. Real-time reverse transcriptase–polymerase chain reaction and Western blot analysis of selected genes/proteins showed > 90% concordance. Arsenic-altered gene expression included activation of oncogenes and HCC biomarkers, and increased expression of cell proliferation–related genes, stress proteins, and insulin-like growth factors and genes involved in cell–cell communications. Liver feminization was evidenced by increased expression of estrogen-linked genes and altered expression of genes that encode gender-related metabolic enzymes. These novel findings are in agreement with the biology and histology of arsenic-induced HCC, thereby indicating that multiple genetic events are associated with transplacental arsenic hepatocarcinogenesis

Intervention effects of Ganoderma lucidum spores on epileptiform discharge hippocampal neurons and expression of Neurotrophin-4 and N-Cadherin

Epilepsy can cause cerebral transient dysfunctions. Ganoderma lucidum spores (GLS), a traditional Chinese medicinal herb, has shown some antiepileptic effects in our previous studies. This was the first study of the effects of GLS on cultured primary hippocampal neurons, treated with Mg2+ free medium. This in vitro model of epileptiform discharge hippocampal neurons allowed us to investigate the anti-epileptic effects and mechanism of GLS activity. Primary hippocampal neurons from <1 day old rats were cultured and their morphologies observed under fluorescence microscope. Neurons were confirmed by immunofluorescent staining of neuron specific enolase (NSE). Sterile method for GLS generation was investigated and serial dilutions of GLS were used to test the maximum non-toxic concentration of GLS on hippocampal neurons. The optimized concentration of GLS of 0.122 mg/ml was identified and used for subsequent analysis. Using the in vitro model, hippocampal neurons were divided into 4 groups for subsequent treatment i) control, ii) model (incubated with Mg2+ free medium for 3 hours), iii) GLS group I (incubated with Mg2+ free medium containing GLS for 3 hours and replaced with normal medium and incubated for 6 hours) and iv) GLS group II (neurons incubated with Mg2+ free medium for 3 hours then replaced with a normal medium containing GLS for 6 hours). Neurotrophin-4 and N-Cadherin protein expression were detected using Western blot. The results showed that the number of normal hippocampal neurons increased and the morphologies of hippocampal neurons were well preserved after GLS treatment. Furthermore, the expression of neurotrophin-4 was significantly increased while the expression of N-Cadherin was decreased in the GLS treated group compared with the model group. This data indicates that GLS may protect hippocampal neurons by promoting neurotrophin-4 expression and inhibiting N-Cadherin expression