Precision Measurements of d(d,p)t and d(d,n)^3He Total Cross Sections at Big-Bang Nucleosynthesis Energies

Recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements have determined the baryon density of the Universe $\Omega_b$ with a precision of about 4%. With $\Omega_b$ tightly constrained, comparisons of Big Bang Nucleosynthesis (BBN) abundance predictions to primordial abundance observations can be made and used to test BBN models and/or to further constrain abundances of isotopes with weak observational limits. To push the limits and improve constraints on BBN models, uncertainties in key nuclear reaction rates must be minimized. To this end, we made new precise measurements of the d(d,p)t and d(d,n)^3He total cross sections at lab energies from 110 keV to 650 keV. A complete fit was performed in energy and angle to both angular distribution and normalization data for both reactions simultaneously. By including parameters for experimental variables in the fit, error correlations between detectors, reactions, and reaction energies were accurately tabulated by computational methods. With uncertainties around 2% +/- 1% scale error, these new measurements significantly improve on the existing data set. At relevant temperatures, using the data of the present work, both reaction rates are found to be about 7% higher than those in the widely used Nuclear Astrophysics Compilation of Reaction Rates (NACRE). These data will thus lead not only to reduced uncertainties, but also to modifications in the BBN abundance predictions.Comment: 15 pages, 11 figures, minor editorial change

Evidence for Three Nucleon Force Effects in p-d Elastic Scattering

A new measurement of the p-d differential cross section at Ep= 1 MeV has been performed. These new data and older data sets at energies below the deuteron breakup are compared to calculations using the two-nucleon Argonne v18 and the three-nucleon Urbana IX potentials. A quantitative estimate of the capability of these interactions to describe the data is given in terms of a chi^2 analysis. The chi^2 per datum drastically improves when the three-nucleon interaction is included in the Hamiltonian.Comment: 13 pages, 5 figures, to be published in Phys. Rev.

Warm Breeze from the starboard bow: a new population of neutral helium in the heliosphere

We investigate the signals from neutral He atoms observed from Earth orbit in 2010 by IBEX. The full He signal observed during the 2010 observation season can be explained as a superposition of pristine neutral interstellar He gas and an additional population of neutral He that we call the Warm Breeze. The Warm Breeze is approximately two-fold slower and 2.5 times warmer than the primary interstellar He population, and its density in front of the heliosphere is ~7% that of the neutral interstellar helium. The inflow direction of the Warm Breeze differs by ~19deg from the inflow direction of interstellar gas. The Warm Breeze seems a long-term feature of the heliospheric environment. It has not been detected earlier because it is strongly ionized inside the heliosphere, which brings it below the threshold of detection via pickup ion and heliospheric backscatter glow observations, as well as by the direct sampling of GAS/Ulysses. Possible sources for the Warm Breeze include (1) the secondary population of interstellar helium, created via charge exchange and perhaps elastic scattering of neutral interstellar He atoms on interstellar He+ ions in the outer heliosheath, or (2) a gust of interstellar He originating from a hypothetic wave train in the Local Interstellar Cloud. A secondary population is expected from models, but the characteristics of the Warm Breeze do not fully conform to modeling results. If, nevertheless, this is the explanation, IBEX-Lo observations of the Warm Breeze provide key insights into the physical state of plasma in the outer heliosheath. If the second hypothesis is true, the source is likely to be located within a few thousand of AU from the Sun, which is the propagation range of possible gusts of interstellar neutral helium with the Warm Breeze characteristics against dissipation via elastic scattering in the Local Cloud.Comment: submitted to ApJ

The Association of Lipoprotein Changes and the Development of Plasma Leakage in Dengue Infection

There’s interrelationship between infection and lipoprotein. This is a cohort prospective study which conducted November 2010 – February 2011. This study aimed to assess the changes of HDL-C, LDL-C, total cholesterol (TC), triglyceride (TG), in acute and critical phase of dengue infection and its association with plasma leakage. Subjects who had fever 48 hours or less and Dengue NS1 antigen test positive were admitted to Cipto Mangunkusumo Hospital Jakarta. We examined clinical and CBC daily; level of albumin, HDL-C, LDL-C, TC, TG; ultrasound to find ascites and pleural effusion. Among 51 subjects, 21 subjects (41%) had plasma leakage. There were significant lower of HDL-C, LDL-C, and higher TG in critical phase than acute phase. In critical phase, subjects with plasma leakage had a significant lower HDL-C level [26.3 (8.2) vs 33.1 (12.1) mg/dL, p=0.029] but not for LDL-C, TC, and TG. They also had a significantly higher reduction in HDL-C [19.6 (9.1) vs 11.5 (5.8) mg/dL, p<0.0001] and TC [25.1 (20.0) vs 15.2 (14.5) mg/dL, 0.045] over the course of acute to critical phase. Lipoprotein changes during dengue infection were more pronounced among subjects who developed plasma leakage. The higher reduction in HDL-C is associated with the development of plasma leakage. &nbsp

Raman scattering from phonons and magnons in RFe3)BO3)4

Inelastic light scattering spectra of several members of the RFe3(BO3)4 family reveal a cascade of phase transitions as a function of temperature, starting with a structural, weakly first order, phase transition followed by two magnetic phase transitions. Those consist of the ordering of the Fe-spin sublattice revealed by all the compound, and a subsequent spin-reorientational transition for GdFe3(BO3)4. The Raman data evidence a strong coupling between the lattice and magnetic degrees of freedom in these borates. The Fe-sublattice ordering leads to a strong suppression of the low energy magnetic scattering, and a multiple peaked two-magnon scattering continuum is observed. Evidence for short-range correlations is found in the `paramagnetic' phase by the observation of a broad magnetic continuum in the Raman data, which persists up to surprisingly high temperatures.Comment: 17 pages, 13 figure

Interaction of Chemistry, Turbulence, and Shock Waves in Hypervelocity Flow

Significant progress was made in the third year of an interdisciplinary experimental, numerical and theoretical program to extend the state of knowledge and understanding of the effects of chemical reactions in hypervelocity flows. The program addressed the key problems in aerothermochemistry that arise from.the interaction between the three strongly nonlinear effects: Compressibility; vorticity; and chemistry. Important new results included: • New data on transition in hypervelocity carbon dioxide flows • New method of free-piston shock tunnel operation for lower enthalpy • Accurate new method for computation of self-similar flows • New experimental data on flap-induced separation at high enthalpy • Insight into mechanisms active in reacting shear layers from comparison of experiment and computation • Extensive new data from Rayleigh scattering diagnostics of supersonic shear layer • Comparison of new experiments and computation of hypervelocity double-wedge flow yielded important differences • Further first-principles computations of electron collision cross-sections of CO, N_2 and NO • Good agreement between EFMO computation and experiment of flow over a cone at high incidence • Extension of LITA diagnostics to high temperature

School violence, school differences and school discourses

This article highlights one strand of a study which investigated the concept of the violenceresilient school. In six inner-city secondary schools, data on violent incidents in school and violent crime in the neighbourhood were gathered, and compared with school practices to minimise violence, accessed through interviews. Some degree of association between the patterns of behaviour and school practices was found: schools with a wider range of wellconnected practices seemed to have less difficult behaviour. Interviews also showed that the different schools had different organisational discourses for construing school violence, its possible causes and the possible solutions. Differences in practices are best understood in connection with differences in these discourses. Some of the features of school discourses are outlined, including their range, their core metaphor and their silences. We suggest that organisational discourse is an important concept in explaining school effects and school differences, and that improvement attempts could have clearer regard to this concept

Vulnerability to bullying in children with a history of specific speech and language difficulties

This is an electronic version of an article published in Lindsay, Geoff and Dockrell, Julie and Mackie, Clare (2008) Vulnerability to bullying in children with a history of specific speech and language difficulties. European Journal of Special Needs Education, 23 (1). pp. 1-16. European Journal of Special Needs Education is available online at: http://www.informaworld.com/10.1080/0885625070179120

Relation Between Einstein And Quantum Field Equations

We show that there exists a choice of scalar field modes, such that the evolution of the quantum field in the zero-mass and large-mass limits is consistent with the Einstein equations for the background geometry. This choice of modes is also consistent with zero production of these particles and thus corresponds to a preferred vacuum state preserved by the evolution. In the zero-mass limit, we find that the quantum field equation implies the Einstein equation for the scale factor of a radiation-dominated universe; in the large-mass case, it implies the corresponding Einstein equation for a matter-dominated universe. Conversely, if the classical radiation-dominated or matter-dominated Einstein equations hold, there is no production of scalar particles in the zero and large mass limits, respectively. The suppression of particle production in the large mass limit is over and above the expected suppression at large mass. Our results hold for a certain class of conformally ultrastatic background geometries and therefore generalize previous results by one of us for spatially flat Robertson-Walker background geometries. In these geometries, we find that the temporal part of the graviton equations reduces to the temporal equation for a massless minimally coupled scalar field, and therefore the results for massless particle production hold also for gravitons. Within the class of modes we study, we also find that the requirement of zero production of massless scalar particles is not consistent with a non-zero cosmological constant. Possible implications are discussed.Comment: Latex, 24 pages. Minor changes in text from original versio