R-Mode Oscillations and Spindown of Young Rotating Magnetic Neutron Stars

Recent work has shown that a young, rapidly rotating neutron star loses angular momentum to gravitational waves generated by unstable r-mode oscillations. We study the spin evolution of a young, magnetic neutron star including both the effects of gravitational radiation and magnetic braking (modeled as magnetic dipole radiation). Our phenomenological description of nonlinear r-modes is similar to, but distinct from, that of Owen et al. (1998) in that our treatment is consistent with the principle of adiabatic invariance in the limit when direct driving and damping of the mode are absent. We show that, while magnetic braking tends to increase the r-mode amplitude by spinning down the neutron star, it nevertheless reduces the efficiency of gravitational wave emission from the star. For B >= 10^14 (\nus/300 Hz)^2 G, where \nus is the spin frequency, the spindown rate and the gravitational waveforms are significantly modified by the effect of magnetic braking. We also estimate the growth rate of the r-mode due to electromagnetic (fast magnetosonic) wave emission and due to Alfven wave emission in the neutron star magnetosphere. The Alfven wave driving of the r-mode becomes more important than the gravitational radiation driving when B >= 10^13 (\nus/150 Hz)^3 G; the electromagnetic wave driving of the r-mode is much weaker. Finally, we study the properties of local Rossby-Alfven waves inside the neutron star and show that the fractional change of the r-mode frequency due to the magnetic field is of order 0.5 (B/10^16 G)^2 (\nus/100 Hz)^-2.Comment: 18 pages, 4 figures; ApJ, accepted (v544: Nov 20, 2000); added two footnotes and more discussion of mode driving by Alfven wave

Impact of edge-removal on the centrality betweenness of the best spreaders

The control of epidemic spreading is essential to avoid potential fatal consequences and also, to lessen unforeseen socio-economic impact. The need for effective control is exemplified during the severe acute respiratory syndrome (SARS) in 2003, which has inflicted near to a thousand deaths as well as bankruptcies of airlines and related businesses. In this article, we examine the efficacy of control strategies on the propagation of infectious diseases based on removing connections within real world airline network with the associated economic and social costs taken into account through defining appropriate quantitative measures. We uncover the surprising results that removing less busy connections can be far more effective in hindering the spread of the disease than removing the more popular connections. Since disconnecting the less popular routes tend to incur less socio-economic cost, our finding suggests the possibility of trading minimal reduction in connectivity of an important hub with efficiencies in epidemic control. In particular, we demonstrate the performance of various local epidemic control strategies, and show how our approach can predict their cost effectiveness through the spreading control characteristics.Comment: 11 pages, 4 figure

Exterior optical cloaking and illusions by using active sources: a boundary element perspective

Recently, it was demonstrated that active sources can be used to cloak any objects that lie outside the cloaking devices [Phys. Rev. Lett. \textbf{103}, 073901 (2009)]. Here, we propose that active sources can create illusion effects, so that an object outside the cloaking device can be made to look like another object. invisibility is a special case in which the concealed object is transformed to a volume of air. From a boundary element perspective, we show that active sources can create a nearly "silent" domain which can conceal any objects inside and at the same time make the whole system look like an illusion of our choice outside a virtual boundary. The boundary element method gives the fields and field gradients (which can be related to monopoles and dipoles) on continuous curves which define the boundary of the active devices. Both the cloaking and illusion effects are confirmed by numerical simulations

H3++H_3^{++} molecular ions can exist in strong magnetic fields

Using the variational method it is shown that for magnetic fields $B\geq 10^{11}$ G there can exist a molecular ion $H_3^{++}$.Comment: LaTeX, 7 pp, 1 table, 4 figures. Title modified. Consideration of the longitudinal size of the system was adde

Enhanced Mechanisms for Navigation and Tracking Services in Smart Phones

Combining Global Positioning System (GPS) and Short Message Service (SMS), this paper develops a realisticsystem, called Mobile Navigation and Tracking System (MNTS), to provide navigation and target tracking services.MNTS is an Android based mobile application which integrated many enhanced mechanisms for navigation andtarget tracking services. MNTS not only provides users with the GPS navigation capability, but also supports QuickResponse (QR) code decoding, nearby scenic spot searching, friend positioning and target tracking. In targettracking, MNTS utilizing SMS mainly adopts two proposed novel approaches: location prediction and dynamicthreshold to reduce the number of short message transmissions while maintaining location accuracy within anacceptable range. Location prediction utilizes the current target’s location, moving speed, bearing to predict its nextlocation. When the distance between the predicted location and the actual location exceeds a threshold, the targetsends a short message to the tracker to update the actual location. Based on the movement speed of the target,the threshold is dynamically adjusted to balance the location accuracy and the number of short messages.Furthermore, as MNTS is free and open-source software, service providers or developers can easily extend theirown services based on this system

Antrodia cinnamomea reduces obesity and modulates the gut microbiota in high-fat diet-fed mice.

BackgroundObesity is associated with gut microbiota dysbiosis, disrupted intestinal barrier and chronic inflammation. Given the high and increasing prevalence of obesity worldwide, anti-obesity treatments that are safe, effective and widely available would be beneficial. We examined whether the medicinal mushroom Antrodia cinnamomea may reduce obesity in mice fed with a high-fat diet (HFD).MethodsMale C57BL/6J mice were fed a HFD for 8 weeks to induce obesity and chronic inflammation. The mice were treated with a water extract of A. cinnamomea (WEAC), and body weight, fat accumulation, inflammation markers, insulin sensitivity and the gut microbiota were monitored.ResultsAfter 8 weeks, the mean body weight of HFD-fed mice was 39.8±1.2 g compared with 35.8±1.3 g for the HFD+1% WEAC group, corresponding to a reduction of 4 g or 10% of body weight (P<0.0001). WEAC supplementation reduced fat accumulation and serum triglycerides in a statistically significant manner in HFD-fed mice. WEAC also reversed the effects of HFD on inflammation markers (interleukin-1β, interleukin-6, tumor necrosis factor-α), insulin resistance and adipokine production (leptin and adiponectin). Notably, WEAC increased the expression of intestinal tight junctions (zonula occludens-1 and occludin) and antimicrobial proteins (Reg3g and lysozyme C) in the small intestine, leading to reduced blood endotoxemia. Finally, WEAC modulated the composition of the gut microbiota, reducing the Firmicutes/Bacteroidetes ratio and increasing the level of Akkermansia muciniphila and other bacterial species associated with anti-inflammatory properties.ConclusionsSupplementation with A. cinnamomea produces anti-obesogenic, anti-inflammatory and antidiabetic effects in HFD-fed mice by maintaining intestinal integrity and modulating the gut microbiota

Serum hepatitis B viral DNA in HBsAg-positive hepatocellular carcinoma treated with interferon or adriamycin.

Sera from 31 HBsAg-positive Chinese patients with inoperable hepatocellular carcinoma (HCC) were tested for hepatitis B virus DNA (HBV DNA) by means of dot hybridisation and Southern blot technique. HBV DNA probes were prepared from human plasma. Eighteen of the patients were HBeAb-positive, 12 were HBeAg-positive and one case had neither marker. Serial specimens were obtained from 16 cases over 5-42 weeks, while the patients were treated with recombinant leukocyte A interferon (rIFN-A) or adriamycin. Seven patients (2 HBeAg-positive, 5 HBeAb-positive) were positive for HBV DNA. In two patients HBV DNA and HBV DNA polymerase (DNAp) appeared in serum weeks after rIFN-A or adriamycin treatment was started. In two other cases, HBV DNA that was initially present disappeared during rIFN-A treatment. In a fifth patient HBV DNA persisting after adriamycin treatment diminished after change of treatment to rIFN-A. With one possible exception the HBV DNA detectable by Southern blot technique was composed chiefly of sequences 2.2-3.2 kb size indicating the presence of unintegrated DNA forms. DNAp activities were raised in the presence of HBV DNA in 4 patients. These findings show that HBV replication can be activated or suppressed in advanced HCC. Treatment with rIFN-A may have been effective in suppressing HBV DNA synthesis, but the number of cases studied was too small to arrive at a definite conclusion on this point

Collider Inclusive Jet Data and the Gluon Distribution

Inclusive jet production data are important for constraining the gluon distribution in the global QCD analysis of parton distribution functions. With the addition of recent CDF and D0 Run II jet data, we study a number of issues that play a role in determining the up-to-date gluon distribution and its uncertainty, and produce a new set of parton distributions that make use of that data. We present in detail the general procedures used to study the compatibility between new data sets and the previous body of data used in a global fit. We introduce a new method in which the Hessian matrix for uncertainties is ``rediagonalized'' to obtain eigenvector sets that conveniently characterize the uncertainty of a particular observable.Comment: Published versio