Reversals of the solar magnetic dipole in the light of observational data and simple dynamo models

Observations show that the photospheric solar magnetic dipole usually does not vanish during the reversal of the solar magnetic field, which occurs in each solar cycle. In contrast, mean-field solar dynamo models predict that the dipole field does become zero. In a recent paper Moss et al. (2013) suggested that this contradiction can be explained as a large-scale manifestation of small-scale magnetic fluctuations of the surface poloidal field. Here we compare this interpretation with WSO (Wilcox Solar Observatory) photospheric magnetic field data in order to determine the amplitude of magnetic fluctuations required to explain the phenomenon and to compare the results with predictions from a simple dynamo model which takes these fluctuations into account. We demonstrate that the WSO data concerning the magnetic dipole reversals are very similar to the predictions of our very simple solar dynamo model, which includes both mean magnetic field and fluctuations. The ratio between the rms value of the magnetic fluctuations and the mean field is estimated to be about 2, in reasonable agreement with estimates from sunspot data. The reversal epoch, during which the fluctuating contribution to the dipole is larger than that from the mean field, is about 4 months. The memory time of the fluctuations is about 2 months. Observations demonstrate that the rms of the magnetic fluctuations is strongly modulated by the phase of the solar cycle. This gives additional support to the concept that the solar magnetic field is generated by a single dynamo mechanism rather than also by independent small-scale dynamo action. A suggestion of a weak nonaxsymmetric magnetic field of a fluctuating nature arises from the analysis, with a lifetime of about 1 year.Comment: 9 pages, 10 figures, accepted versio

Variables Explaining Bank Stock Prices

The purpose of this study is to examine the relationship between an index of bank common stock prices and a variety of explanatory variables including interest rates on Treasury securities of various maturities and other economic variables.  We also examine the relationship between the term structure of interest rates and bank stock prices.  A sample of week ending values of the bank stock index is used as a proxy for the bank industry.  The weekly closing interest rates for the 13-week Treasury bill, 5-year Treasury note, 10-year Treasury note and the 30-year Treasury bond are used in the study.  Other data used were the U.S. dollar index, the CRB index, the price of gold, the S&P500 stock index, the VIX stock market volatility index and a measure of the yield curve.  Data was taken from January 1998 through November 2009.  Therefore, a total of approximately 620 cases of weekly observations are included in the study.  In order to study the effects of term structure of interest rates on bank stock prices, we take the difference between the 10-year Note and the 13-week Bill.  All variables are converted to a stationary series by taking first differences of each series.  Multiple linear regression is then used to study the variables that can explain bank stock prices.  A stepwise procedure was used to identify those variables with the strongest relationships in a multi-variable equation.  Three independent variables were found with an R-squared of 0.619.  The results of this study corroborate previous studies and have practical implications for investors and for bank managers

High accuracy results for the energy levels of the molecular ions H2+, D2+ and HD+, up to J=2

We present a nonrelativistic calculation of the rotation-vibration levels of the molecular ions H2+, D2+ and HD+, relying on the diagonalization of the exact three-body Hamiltonian. The J=2 levels are obtained with a very high accuracy of 10^{-14} a.u. (for most levels) representing an improvement by five orders of magnitude over previous calculations. The accuracy is also improved for the J=1 levels of H2+ and D2+ with respect to earlier works. Moreover, we have computed the sensitivities of the energy levels with respect to the mass ratios, allowing these levels to be used for metrological purposes.Comment: 11 page

Investigation in haemodynamic stability during intermittent haemodialysis in the critically ill

No abstract available

Towards a lightweight generic computational grid framework for biological research

Background: An increasing number of scientific research projects require access to large-scale computational resources. This is particularly true in the biological field, whether to facilitate the analysis of large high-throughput data sets, or to perform large numbers of complex simulations – a characteristic of the emerging field of systems biology. Results: In this paper we present a lightweight generic framework for combining disparate computational resources at multiple sites (ranging from local computers and clusters to established national Grid services). A detailed guide describing how to set up the framework is available from the following URL: http://igrid-ext.cryst.bbk.ac.uk/portal_guide/. Conclusion: This approach is particularly (but not exclusively) appropriate for large-scale biology projects with multiple collaborators working at different national or international sites. The framework is relatively easy to set up, hides the complexity of Grid middleware from the user, and provides access to resources through a single, uniform interface. It has been developed as part of the European ImmunoGrid project

An investigation into the effects of commencing haemodialysis in the critically ill

<b>Introduction:</b> We have aimed to describe haemodynamic changes when haemodialysis is instituted in the critically ill. 3 hypotheses are tested: 1)The initial session is associated with cardiovascular instability, 2)The initial session is associated with more cardiovascular instability compared to subsequent sessions, and 3)Looking at unstable sessions alone, there will be a greater proportion of potentially harmful changes in the initial sessions compared to subsequent ones. <b>Methods:</b> Data was collected for 209 patients, identifying 1605 dialysis sessions. Analysis was performed on hourly records, classifying sessions as stable/unstable by a cutoff of >+/-20% change in baseline physiology (HR/MAP). Data from 3 hours prior, and 4 hours after dialysis was included, and average and minimum values derived. 3 time comparisons were made (pre-HD:during, during HD:post, pre-HD:post). Initial sessions were analysed separately from subsequent sessions to derive 2 groups. If a session was identified as being unstable, then the nature of instability was examined by recording whether changes crossed defined physiological ranges. The changes seen in unstable sessions could be described as to their effects: being harmful/potentially harmful, or beneficial/potentially beneficial. <b>Results:</b> Discarding incomplete data, 181 initial and 1382 subsequent sessions were analysed. A session was deemed to be stable if there was no significant change (>+/-20%) in the time-averaged or minimum MAP/HR across time comparisons. By this definition 85/181 initial sessions were unstable (47%, 95% CI SEM 39.8-54.2). Therefore Hypothesis 1 is accepted. This compares to 44% of subsequent sessions (95% CI 41.1-46.3). Comparing these proportions and their respective CI gives a 95% CI for the standard error of the difference of -4% to 10%. Therefore Hypothesis 2 is rejected. In initial sessions there were 92/1020 harmful changes. This gives a proportion of 9.0% (95% CI SEM 7.4-10.9). In the subsequent sessions there were 712/7248 harmful changes. This gives a proportion of 9.8% (95% CI SEM 9.1-10.5). Comparing the two unpaired proportions gives a difference of -0.08% with a 95% CI of the SE of the difference of -2.5 to +1.2. Hypothesis 3 is rejected. Fisher’s exact test gives a result of p=0.68, reinforcing the lack of significant variance. <b>Conclusions:</b> Our results reject the claims that using haemodialysis is an inherently unstable choice of therapy. Although proportionally more of the initial sessions are classed as unstable, the majority of MAP and HR changes are beneficial in nature

Instructional Case: Java & Holes

The primary subject matter of this case concerns a review of earnings per share, ratio analysis, and cost of capital concepts.  A secondary issue includes evaluation of alternative strategies within the constraints of debt covenants.  The case was designed to use as a review of financial accounting concepts in a MBA managerial accounting course.  However, the case has a difficulty level appropriate for seniors or first or second year graduate students.  The case is designed as a review and should be completed entirely outside of class.  Depending on financial background, students will require approximately ten to fifteen hours to complete the case

Fabrication of thick structures by sputtering

Deposit, 5500-gram of Cu-0.15 wt % Zr alloy, sputtered onto copper cylinder to average thickness of 12.29 mm. Structure was achieved with high-rate sputter deposition for about 100 hours total sputtering time. Material had twice the strength of unsputtered material at temperatures to 723 K and equivalent strength at nearly 873 K

Surface-slip equations for multicomponent nonequilibrium air flow

Equations are presented for the surface-slip (or jump) values of species concentration, pressure, velocity, and temperature in the low-Reynolds number, high-altitude flight regime of a space vehicle. The equations are obtained from closed form solutions of the mass, momentum, and energy flux equations using the Chapman-Enskog velocity distribution function. This function represents a solution of the Boltzmann equation in the Navier-Stokes approximation. The analysis, obtained for nonequilibrium multicomponent air flow, includes the finite-rate surface catalytic recombination and changes in the internal energy during reflection from the surface. Expressions for the various slip quantities were obtained in a form which can be employed in flowfield computations. A consistent set of equations is provided for multicomponent, binary, and single species mixtures. Expression is also provided for the finite-rate, species-concentration boundary condition for a multicomponent mixture in absence of slip