One-Up On L1: Can X-rays Provide Longer Advanced Warning of Solar Wind Flux Enhancements Than Upstream Monitors?

Observations of strong solar wind proton flux correlations with ROSAT X-ray rates along with high spectral resolution Chandra observations of X-rays from the dark Moon show that soft X-ray emission mirrors the behavior of the solar wind. In this paper, based on an analysis of an X-ray event observed by XMM-Newton resulting from charge exchange of high charge state solar wind ions and contemporaneous neutral solar wind data, we argue that X-ray observations may be able to provide reliable advance warning, perhaps by as much as half a day, of dramatic increases in solar wind flux at Earth. Like neutral atom imaging, this provides the capability to monitor the solar wind remotely rather than in-situ.Comment: in press in Adv. Space Research, 7 pages, 6 eps figures, resolution reduced for Astro-ph submission, see http://lena.gsfc.nasa.gov for full versio

The CXCL12/CXCR4 signaling axis retains neutrophils at inflammatory sites in zebrafish

The inappropriate retention of neutrophils at inflammatory sites is a major driver of the excessive tissue damage characteristic of respiratory inflammatory diseases including COPD, ARDS, and cystic fibrosis. The molecular programmes which orchestrate neutrophil recruitment to inflammatory sites through chemotactic guidance have been well-studied. However, how neutrophil sensitivity to these cues is modulated during inflammation resolution is not understood. The identification of neutrophil reverse migration as a mechanism of inflammation resolution and the ability to modulate this therapeutically has identified a new target to treat inflammatory disease. Here we investigate the role of the CXCL12/CXCR4 signaling axis in modulating neutrophil retention at inflammatory sites. We used an in vivo tissue injury model to study neutrophilic inflammation using transgenic zebrafish larvae. Expression of cxcl12a and cxcr4b during the tissue damage response was assessed using in situ hybridization and analysis of RNA sequencing data. CRISPR/Cas9 was used to knockdown cxcl12a and cxcr4b in zebrafish larvae. The CXCR4 antagonist AMD3100 was used to block the Cxcl12/Cxcr4 signaling axis pharmacologically. We identified that cxcr4b and cxcl12a are expressed at the wound site in zebrafish larvae during the inflammatory response. Following tail-fin transection, removal of neutrophils from inflammatory sites is significantly increased in cxcr4b and cxcl12a CRISPR knockdown larvae. Pharmacological inhibition of the Cxcl12/Cxcr4 signaling axis accelerated resolution of the neutrophil component of inflammation, an effect caused by an increase in neutrophil reverse migration. The findings of this study suggest that CXCR4/CXCL12 signaling may play an important role in neutrophil retention at inflammatory sites, identifying a potential new target for the therapeutic removal of neutrophils from the lung in chronic inflammatory disease

Nonperturbative Renormalization and the QCD Vacuum

We present a self consistent approach to Coulomb gauge Hamiltonian QCD which allows one to relate single gluon spectral properties to the long range behavior of the confining interaction. Nonperturbative renormalization is discussed. The numerical results are in good agreement with phenomenological and lattice forms of the static potential.Comment: 23 pages in RevTex, 4 postscript figure

Friedmann-like equations for High Energy Area of Universe

In this paper, evolution of the high energy area of universe, through the scenario of 5 dimensional (5D) universe, has been studied. For this purpose, we solve Einstein equations for 5D metric and 5D perfect fuid to derive Friedmann-like equations. Then we obtain the evolution of scale factor and energy density with respect to both space-like and time-like extra dimensions. We obtain the novel equations for the space-like extra dimension and show that the matter with zero pressure cannot exist in the bulk. Also, for dark energy fuid and vacuum fluid, we have both accelerated expansion and contraction in the bulk.Comment: 9 pages, Accepted to publication in IJTP 26 June 2012. arXiv admin note: substantial text overlap with arXiv:1202.497

Ambient particulate pollution and the world-wide prevalence of asthma, rhinoconjunctivitis and eczema in children: Phase One of the International Study of Asthma and Allergies in Childhood (ISAAC)

Objectives: To investigate the effect of ambient particulate matter on variation in childhood prevalence of asthma, rhinoconjunctivitis and eczema. Methods: Prevalences of asthma, rhinoconjunctivitis and eczema obtained in Phase One of the International Study of Asthma and Allergies in Childhood (ISAAC) were matched with city-level estimates of residential PM10 obtained from a World Bank model. Associations were investigated using binomial regression adjusting for GNP per capita and for clustering within country. For countries with more than one centre, a two stage meta-analysis was carried out. The results were compared with a meta-analysis of published multi-centre studies. Results: Annual concentrations of PM₁₀ at city level were obtained for 105 ISAAC centres in 51 countries. After controlling for GNP per capita, there was a weak negative association between PM₁₀ and various outcomes. For severe wheeze in 13-14-year-olds, the OR for a 10 μg/m³ increase in PM₁₀ was 0.92 (95 CI 0.84 to 1.00). In 24 countries with more than one centre, most summary estimates for within-country associations were weakly positive. For severe wheeze in 13-14-year-olds, the summary OR for a 10 μg/m³ increase in PM₁₀ was 1.01 (0.92 to 1.10). This result was close to a summary OR of 0.99 (0.91 to 1.06) obtained from published multi-centre studies. Conclusions: Modelled estimates of particulate matter at city level are imprecise and incomplete estimates of personal exposure to ambient air pollutants. Nevertheless, our results together with those of previous multi-centre studies, suggest that urban background PM₁₀ has little or no association with the prevalence of childhood asthma, rhinoconjunctivitis or eczema either within or between countries

Questioning Glutamate Excitotoxicity in Acute Brain Damage: The Importance of Spreading Depolarization

Background: Within 2 min of severe ischemia, spreading depolarization (SD) propagates like a wave through compromised gray matter of the higher brain. More SDs arise over hours in adjacent tissue, expanding the neuronal damage. This period represents a therapeutic window to inhibit SD and so reduce impending tissue injury. Yet most neuroscientists assume that the course of early brain injury can be explained by glutamate excitotoxicity, the concept that immediate glutamate release promotes early and downstream brain injury. There are many problems with glutamate release being the unseen culprit, the most practical being that the concept has yielded zero therapeutics over the past 30 years. But the basic science is also flawed, arising from dubious foundational observations beginning in the 1950s Methods: Literature pertaining to excitotoxicity and to SD over the past 60 years is critiqued. Results: Excitotoxicity theory centers on the immediate and excessive release of glutamate with resulting neuronal hyperexcitation. This instigates poststroke cascades with subsequent secondary neuronal injury. By contrast, SD theory argues that although SD evokes some brief glutamate release, acute neuronal damage and the subsequent cascade of injury to neurons are elicited by the metabolic stress of SD, not by excessive glutamate release. The challenge we present here is to find new clinical targets based on more informed basic science. This is motivated by the continuing failure by neuroscientists and by industry to develop drugs that can reduce brain injury following ischemic stroke, traumatic brain injury, or sudden cardiac arrest. One important step is to recognize that SD plays a central role in promoting early neuronal damage. We argue that uncovering the molecular biology of SD initiation and propagation is essential because ischemic neurons are usually not acutely injured unless SD propagates through them. The role of glutamate excitotoxicity theory and how it has shaped SD research is then addressed, followed by a critique of its fading relevance to the study of brain injury. Conclusions: Spreading depolarizations better account for the acute neuronal injury arising from brain ischemia than does the early and excessive release of glutamate.Grants to RDA from the Canadian Heart & Stroke Foundation, National Science Engineering and Research Council and the New Frontiers in Research Fund, to E.F from the National Research, Development and Innovation Office of Hungary, grant no. K134377; and the EU’s Horizon 2020 research and innovation program under grant agreement No. 739593, and to JPD from the DFG (German research Council) (DFG DR323/5-1,DFG DR 323/10-1) BMBF Bundesministerium fuer Bildung und Forschung (Era-Net Neuron EBio2, with funds from BMBF 01EW2004)

The Critical Role of Spreading Depolarizations in Early Brain Injury: Consensus and Contention

Background: When a patient arrives in the emergency department following a stroke, a traumatic brain injury, or sudden cardiac arrest, there is no therapeutic drug available to help protect their jeopardized neurons. One crucial reason is that we have not identified the molecular mechanisms leading to electrical failure, neuronal swelling, and blood vessel constriction in newly injured gray matter. All three result from a process termed spreading depolarization (SD). Because we only partially understand SD, we lack molecular targets and biomarkers to help neurons survive after losing their blood flow and then undergoing recurrent SD. Methods: In this review, we introduce SD as a single or recurring event, generated in gray matter following lost blood flow, which compromises the Na/K pump. Electrical recovery from each SD event requires so much energy that neurons often die over minutes and hours following initial injury, independent of extracellular glutamate. Results: We discuss how SD has been investigated with various pitfalls in numerous experimental preparations, how overtaxing the Na/K ATPase elicits SD. Elevated K or glutamate are unlikely natural activators of SD. We then turn to the properties of SD itself, focusing on its initiation and propagation as well as on computer modeling. Conclusions: Finally, we summarize points of consensus and contention among the authors as well as where SD research may be heading. In an accompanying review, we critique the role of the glutamate excitotoxicity theory, how it has shaped SD research, and its questionable importance to the study of early brain injury as compared with SD theory.This work was supported by grants from the Heart and Stroke Foundation of Canada and the National Science and Engineering Research Council of Canada to RDA, an NIH grant (NS106901) to CWS, a National Research, Development and Innovation Office of Hungary grant (K1343777) and EU Horizon 2020 research and innovation program (739953) to EF and from DFG Deutsche Forschungsgemeinschaft (German Research Council) (DFG DR 323/5-1), DFG DR 323/10-1, and BMBF Bundesministerium fuer Bildung und Forschung (EraNet Neuron EBio2, with funds from BMBF 01EW2004) to JPD

Scaling properties of composite information measures and shape complexity for hydrogenic atoms in parallel magnetic and electric fields

The scaling properties of various composite information-theoretic measures (Shannon and R\'enyi entropy sums, Fisher and Onicescu information products, Tsallis entropy ratio, Fisher-Shannon product and shape complexity) are studied in position and momentum spaces for the non-relativistic hydrogenic atoms in the presence of parallel magnetic and electric fields. Such measures are found to be invariant at the fixed values of the scaling parameters given by $s_1 = B \hbar^3(4\pi\epsilon_0)^2 / (Z^2m^2e^3)$ and $s_2 = F \hbar^4(4\pi\epsilon_0)^3 / (Z^3e^5m^2)$. Numerical results which support the validity of the scaling properties are shown by choosing the representative example of the position space shape complexity. Physical significance of the resulting scaling behaviour is discussed.Comment: 10 pages, 2 figure

An Effective-Medium Tight-Binding Model for Silicon

A new method for calculating the total energy of Si systems is presented. The method is based on the effective-medium theory concept of a reference system. Instead of calculating the energy of an atom in the system of interest a reference system is introduced where the local surroundings are similar. The energy of the reference system can be calculated selfconsistently once and for all while the energy difference to the reference system can be obtained approximately. We propose to calculate it using the tight-binding LMTO scheme with the Atomic-Sphere Approximation(ASA) for the potential, and by using the ASA with charge-conserving spheres we are able to treat open system without introducing empty spheres. All steps in the calculational method is {\em ab initio} in the sense that all quantities entering are calculated from first principles without any fitting to experiment. A complete and detailed description of the method is given together with test calculations of the energies of phonons, elastic constants, different structures, surfaces and surface reconstructions. We compare the results to calculations using an empirical tight-binding scheme.Comment: 26 pages (11 uuencoded Postscript figures appended), LaTeX, CAMP-090594-

Revising the Local Bubble Model due to Solar Wind Charge Exchange X-ray Emission

The hot Local Bubble surrounding the solar neighborhood has been primarily studied through observations of its soft X-ray emission. The measurements were obtained by attributing all of the observed local soft X-rays to the bubble. However, mounting evidence shows that the heliosphere also produces diffuse X-rays. The source is solar wind ions that have received an electron from another atom. The presence of this alternate explanation for locally produced diffuse X-rays calls into question the existence and character of the Local Bubble. This article addresses these questions. It reviews the literature on solar wind charge exchange (SWCX) X-ray production, finding that SWCX accounts for roughly half of the observed local 1/4 keV X-rays found at low latitudes. This article also makes predictions for the heliospheric O VI column density and intensity, finding them to be smaller than the observational error bars. Evidence for the continued belief that the Local Bubble contains hot gas includes the remaining local 1/4 keV intensity, the observed local O VI column density, and the need to fill the local region with some sort of plasma. If the true Local Bubble is half as bright as previously thought, then its electron density and thermal pressure are 1/square-root(2) as great as previously thought, and its energy requirements and emission measure are 1/2 as great as previously thought. These adjustments can be accommodated easily, and, in fact, bring the Local Bubble's pressure more in line with that of the adjacent material. Suggestions for future work are made.Comment: 9 pages, refereed, accepted for publication in the proceedings of the "From the Outer Heliosphere to the Local Bubble: Comparisons of New Observations with Theory" conference and in Space Science Review