Exact General Relativistic Thick Disks

A method to construct exact general relativistic thick disks that is a simple generalization of the ``displace, cut and reflect'' method commonly used in Newtonian, as well as, in Einstein theory of gravitation is presented. This generalization consists in the addition of a new step in the above mentioned method. The new method can be pictured as a ``displace, cut, {\it fill} and reflect'' method. In the Newtonian case, the method is illustrated in some detail with the Kuzmin-Toomre disk. We obtain a thick disk with acceptable physical properties. In the relativistic case two solutions of the Weyl equations, the Weyl gamma metric (also known as Zipoy-Voorhees metric) and the Chazy-Curzon metric are used to construct thick disks. Also the Schwarzschild metric in isotropic coordinates is employed to construct another family of thick disks. In all the considered cases we have non trivial ranges of the involved parameter that yield thick disks in which all the energy conditions are satisfied.Comment: 11 pages, RevTex, 9 eps figs. Accepted for publication in PR

Virus Infections in Children in a Respiratory Intensive Care Unit during an Influenza Epidemic

The incidence and severity of virus infections in a children's respiratory intensive care unit during an influenza A epidemic were studied. Infections caused by the Port Chalmers strain of influenza A or by an adenovirus were associated with severe, often fatal, pneumonia, whereas infections caused by respiratory syncytial virus or cytomegalovirus carried a good prognosis

Modulation of Functional Activities of Chicken Heterophils by Recombinant Chicken IFN-γ

The objective of the present studies was to examine the in vitro effects of recombinant chicken interferon-γ (rChIFN-γ) on shape change, phagocytosis, and the oxidative/nonoxidative killing activities of day-old chicken heterophils. Heterophils (4 × 106/ml) were incubated with various concentrations of recombinant ChIFN-γ from both Escherichia coli and transfected Cos cells for 2 h at 39°C. The incubation of the neonatal heterophils with rChIFN-γ resulted in significantly greater numbers of cells with membrane shape change when compared with the mock-treated heterophils. Both Cos cell-derived and E. coli-derived ChIFN-γ significantly increased (p < 0.01) the phagocytosis of opsonized or nonopsonized Salmonella enteritidis by the neonatal heterophils in a concentration-dependent manner. Incubation with ChIFN-γ induced no direct stimulation of the respiratory burst by the chicken heterophils but did prime the heterophils for a significantly strengthened respiratory burst to subsequent stimulation with opsonized zymosan (OZ). Lastly, incubation of the heterophils with ChIFN-γ primed the cells for a significant increase in the release of β-D-glucuronidase following stimulation with OZ. These results show that neonatal avian heterophils can respond to cytokine modulation with enhanced functional competence, suggesting that ChIFN-γ can enhance the immune competence of the innate defenses of chickens during the first week of life

The role of self-treatment guidelines in self-management education for adult asthmatics

Guidelines on asthma management have changed considerably in the last two decades. Patient education has gained in popularity and especially asthma self-management training is thought to be essential in the treatment of adult asthma. Since 1989 many researchers have added self-treatment guidelines to self-management programmes and several studies have found improvements in health outcomes, such as lung function, quality of life, use of health care facilities and asthma symptoms. However, because of the lack of proper control groups, it is not clear whether this has to be attributed to self-treatment guidelines or to, for example, more education or more medical attention. The only two studies that were placebo controlled did not show an effect of self-treatment. To assess the added benefit of self-treatment guidelines to a self-management programme, randomized ‘placebo’ controlled trials of sufficient size with sufficient follow-up time are necessary. The only difference between intervention and control groups should be guidelines for self-treatment

Inhalation technique of 166 adult asthmatics prior to and following a self-management prograM

Self-management of asthma and self-treatment of exacerbations are considered important in the treatment of asthma. For successful self-treatment, medication has to be inhaled correctly, but the percentage of patients inhaling effectively varies widely. As part of a self-management program we checked and corrected inhalation technique. This paper addresses differences among inhalers in relation to patient characteristics and the effect of instruction, 1 year after enrollment. Maneuvers that are essential for adequate inhalation were identified. When errors in inhalation technique were observed, patients were instructed in the correct use of their devices. One year later, inhalation technique was checked again. Only patients who used the same inhaler throughout the entire study period were analyzed. Of the 245 adult asthmatic patients who were enrolled in the self-management program, 166 used the same inhaler throughout the study period. One hundred twenty patients (72%) performed all key items correctly at baseline and this increased to 80% after 1 year. At follow-up, older patients were less likely to demonstrate a perfect inhalation. Patients with a Diskhaler(r) made fewest errors. Adjustment for differences in patient characteristics did not significantly change the results. Because many patients with asthma use their inhaler ineffectively, there is a need to know which inhaler leads to fewest errors. Diskhaler was nominated by this study. When patients are not able to demonstrate adequate inhalation technique in a “tranquil” setting, it is doubtful that they can do so when they experience an exacerbation. Therefore, inhalation instruction should be considered an essential ingredient, not only of self-management programs, but also of asthma patient care in general

Star-graph expansions for bond-diluted Potts models

We derive high-temperature series expansions for the free energy and the susceptibility of random-bond $q$-state Potts models on hypercubic lattices using a star-graph expansion technique. This method enables the exact calculation of quenched disorder averages for arbitrary uncorrelated coupling distributions. Moreover, we can keep the disorder strength $p$ as well as the dimension $d$ as symbolic parameters. By applying several series analysis techniques to the new series expansions, one can scan large regions of the $(p,d)$ parameter space for any value of $q$. For the bond-diluted 4-state Potts model in three dimensions, which exhibits a rather strong first-order phase transition in the undiluted case, we present results for the transition temperature and the effective critical exponent $\gamma$ as a function of $p$ as obtained from the analysis of susceptibility series up to order 18. A comparison with recent Monte Carlo data (Chatelain {\em et al.}, Phys. Rev. E64, 036120(2001)) shows signals for the softening to a second-order transition at finite disorder strength.Comment: 8 pages, 6 figure

Heavy Quark Photoproduction in Ultra-peripheral Heavy Ion Collisions

Heavy quarks are copiously produced in ultra-peripheral heavy ion collisions. In the strong electromagnetic fields, c c-bar and b b-bar are produced by photonuclear and two-photon interactions; hadroproduction can occur in grazing interactions. We present the total cross sections, quark transverse momentum and rapidity distributions, as well as the Q Q-bar invariant mass spectra from the three production channels. We consider AA and pA collisions at the Relativistic Heavy Ion Collider and Large Hadron Collider. We discuss techniques for separating the three processes and describe how the AA to pA production ratios might be measured accurately enough to study nuclear shadowing.Comment: Minor changes to satisfy referees and typo fixes; 52 pages including 17 figure

How emergency managers (mis?)interpret forecasts

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146849/1/disa12293.pd

Electrovacuum Static Counterrotating Relativistic Dust Disks

A detailed study is presented of the counterrotating model (CRM) for generic electrovacuum static axially symmetric relativistic thin disks without radial pressure. We find a general constraint over the counterrotating tangential velocities needed to cast the surface energy-momentum tensor of the disk as the superposition of two counterrotating charged dust fluids. We also find explicit expressions for the energy densities, charge densities and velocities of the counterrotating fluids. We then show that this constraint can be satisfied if we take the two counterrotating streams as circulating along electro-geodesics. However, we show that, in general, it is not possible to take the two counterrotating fluids as circulating along electro-geodesics nor take the two counterrotating tangential velocities as equal and opposite. Four simple families of models of counterrotating charged disks based on Chazy-Curzon-like, Zipoy-Voorhees-like, Bonnor-Sackfield-like and Kerr-like electrovacuum solutions are considered where we obtain some disks with a CRM well behaved. The models are constructed using the well-known ``displace, cut and reflect'' method extended to solutions of vacuum Einstein-Maxwell equations.Comment: 19 pages, 16 figures, revtex

Characterization of neutrino signals with radiopulses in dense media through the LPM effect

We discuss the possibilities of detecting radio pulses from high energy showers in ice, such as those produced by PeV and EeV neutrino interactions. It is shown that the rich radiation pattern structure in the 100 MHz to few GHz allows the separation of electromagnetic showers induced by photons or electrons above 100 PeV from those induced by hadrons. This opens up the possibility of measuring the energy fraction transmitted to the electron in a charged current electron neutrino interaction with adequate sampling of the angular distribution of the signal. The radio technique has the potential to complement conventional high energy neutrino detectors with flavor information.Comment: 5 pages, 4 ps figures. Submitted to Phys. Rev. Let