Deconvolution of directly precipitating and trap-precipitating electrons in solar flare hard x-rays. III.Yohkoh hard x-ray telescope data analysis

We analyze the footpoint separation d and flux asymmetry A of magnetically conjugate double footpoint sources in hard X-ray images from the Yohkoh Hard X-Ray Telescope (HXT). The data set of 54 solar flares includes all events simultaneously observed with the Compton Gamma Ray Observatory (CGRO) in high time resolution mode. From the CGRO data we deconvolved the direct-precipitation and trap-precipitation components previously (in Paper II). Using the combined measurements from CGRO and HXT, we develop an asymmetric trap model that allows us to quantify the relative fractions of four different electron components, i.e., the ratios of direct-precipitating (q_P1, q_P2) and trap-precipitating electrons (q_T1, q_T2) at both magnetically conjugate footpoints. We find mean ratios of q_P1=0.14+/-0.06, q_P2=0.26+/-0.10, and q_T=q_T1+q_T2=0.60+/-0.13. We assume an isotropic pitch-angle distribution at the acceleration site and double-sided trap precipitation (q_T2/q_T1=q_P2/q_P1) to determine the conjugate loss-cone angles (alpha_1=42^deg+/-11^deg and alpha_2=52^deg+/-10^deg) and magnetic mirror ratiosat both footpoints (R_1=1.6,...,4.0 and R_2=1.3,...,2.5). From the relative displacement of footpoint sources we also measure altitude differences of hard X-ray emission at different energies, which are found to decrease systematically with higher energies, with a statistical height difference of h_Lo-h_M1=980+/-250 km and h_M1-h_M2=310+/-300 km between the three lower HXT energy channels (Lo, M1, M2

Large-scale cosmic flows and moving dark energy

Large-scale matter bulk flows with respect to the cosmic microwave background have very recently been detected on scales 100 Mpc/h and 300 Mpc/h by using two different techniques showing an excellent agreement in the motion direction. However, the unexpectedly large measured amplitudes are difficult to understand within the context of standard LCDM cosmology. In this work we show that the existence of such a flow could be signaling the presence of moving dark energy at the time when photons decoupled from matter. We also comment on the relation between the direction of the CMB dipole and the preferred axis observed in the quadrupole in this scenario.Comment: 11 pages, 2 figures. New comments and references included. Final version to appear in JCA

Relaxed MHD states of a multiple region plasma

We calculate the stability of a multiple relaxation region MHD (MRXMHD) plasma, or stepped-Beltrami plasma, using both variational and tearing mode treatments. The configuration studied is a periodic cylinder. In the variational treatment, the problem reduces to an eigenvalue problem for the interface displacements. For the tearing mode treatment, analytic expressions for the tearing mode stability parameter $\Delta'$, being the jump in the logarithm in the helical flux across the resonant surface, are found. The stability of these treatments is compared for $m=1$ displacements of an illustrative RFP-like configuration, comprising two distinct plasma regions. For pressure-less configurations, we find the marginal stability conclusions of each treatment to be identical, confirming analytic results in the literature. The tearing mode treatment also resolves ideal MHD unstable solutions for which $\Delta' \to \infty$: these correspond to displacement of a resonant interface. Wall stabilisation scans resolve the internal and external ideal kink. Scans with increasing pressure are also performed: these indicate that both variational and tearing mode treatments have the same stability trends with $\beta$, and show pressure stabilisation in configurations with increasing edge pressure. Combined, our results suggest that MRXMHD configurations which are stable to ideal perturbations plus tearing modes are automatically in a stable state. Such configurations, and their stability properties, are of emerging importance in the quest to find mathematically rigorous solutions of ideal MHD force balance in 3D geometry.Comment: 11 pages, 3 figures, 22nd IAEA Fusion Energy Conference, Geneva, Switzerland. Submitted to Nuclear Fusio

Large-scale collective motion of RFGC galaxies

We processed the data about radial velocities and HI linewidths for 1678 flat edge-on spirals from the Revised Flat Galaxy Catalogue. We obtained the parameters of the multipole components of large-scale velocity field of collective non-Hubble galaxy motion as well as the parameters of the generalized Tully-Fisher relationship in the "HI line width - linear diameter" version. All the calculations were performed independently in the framework of three models, where the multipole decomposition of the galaxy velocity field was limited to a dipole, quadrupole and octopole terms respectively. We showed that both the quadrupole and the octopole components are statistically significant. On the basis of the compiled list of peculiar velocities of 1623 galaxies we obtained the estimations of cosmological parameters Omega_m and sigma_8. This estimation is obtained in both graphical form and as a constraint of the value S_8=sigma_8(Omega_m/0.3)^0.35 = 0.91 +/- 0.05.Comment: Accepted for publication in Astrophysics and Space Scienc

Solid‐Phase Synthesis of Branched Oligonucleotides

Branched nucleic acids (bNAs) have been of particular interest since the discovery of RNA forks and lariats as intermediates of nuclear mRNA splicing, as well as multicopy, single‐stranded DNA (msDNA). Such molecules contain the inherent trait of vicinal 2′,5′‐ and 3′,5′‐phosphodiester linkages. bNAs have many potential applications in nucleic acid biochemistry, particularly as tools for studying the substrate specificity of lariat debranching enzymes, and as biological probes for the investigation of branch recognition during pre‐mRNA splicing. The protocols described herein allow for the facile solid‐phase synthesis of branched DNA and/or RNA oligonucleotides of varying chain length, containing symmetrical or asymmetrical sequences immediate to an RNA branch point. The synthetic methodology utilizes widely adopted phosphoramidite chemistry. Methods for efficient purification of bNAs via anion‐exchange HPLC and PAGE are also illustrated.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143634/1/cpnc0414.pd

Large-scale collective motion of RFGC galaxies in curved space-time

We consider large-scale collective motion of flat edge-on spiral galaxies from the Revised Flat Galaxy Catalogue (RFGC) taking into account the curvature of space-time in the Local Universe at the scale 100 Mpc/h. We analyse how the relativistic model of collective motion should be modified to provide the best possible values of parameters, the effects that impact these parameters and ways to mitigate them. Evolution of galactic diameters, selection effects, and difference between isophotal and angular diameter distances are inadequate to explain this impact. At the same time, measurement error in HI line widths and angular diameters can easily provide such an impact. This is illustrated in a toy model, which allows analytical consideration, and then in the full model using Monte Carlo simulations. The resulting velocity field is very close to that provided by the non-relativistic model of motion. The obtained bulk flow velocity is consistent with {\Lambda}CDM cosmology.Comment: 10 pages, 3 figures, 2 table

Energy Release During Slow Long Duration Flares Observed by RHESSI

Slow Long Duration Events (SLDEs) are flares characterized by long duration of rising phase. In many such cases impulsive phase is weak with lack of typical short-lasting pulses. Instead of that smooth, long-lasting Hard X-ray (HXR) emission is observed. We analysed hard X-ray emission and morphology of six selected SLDEs. In our analysis we utilized data from RHESSI and GOES satellites. Physical parameters of HXR sources were obtained from imaging spectroscopy and were used for the energy balance analysis. Characteristic time of heating rate decrease, after reaching its maximum value, is very long, which explains long rising phase of these flares.Comment: Accepted for publication in Solar Physic

NOAO fundamental plane survey II: Age and metallicity along the red sequence from line-strength data

We present spectroscopic line-strength data for 4097 red-sequence galaxies in 93 low-redshift galaxy clusters and use these to investigate variations in average stellar populations as a function of galaxy mass. Our analysis includes an improved treatment of nebular emission contamination, which affects 10% of the sample galaxies. Using the stellar population models of D. Thomas and collaborators, we simultaneously fit 12 observed line-strength relations in terms of common underlying trends of age, [Z/H] (total metallicity), and [/Fe] (-element enhancement). We find that the observed line-strength relations can be explained only if higher mass red-sequence galaxies are, on average, older, more metal-rich, and more -enhanced than lower mass galaxies. Quantitatively, the scaling relations are age0.59±0.13, Z/H0.53±0.08, and /Fe0.31±0.06, where the errors reflect the range obtained using different subsets of indices. Our conclusions are not strongly dependent on which Balmer lines are used as age indicators. The derived age- relation is such that if the largest (400 km s-1) galaxies formed their stars 13 Gyr ago, then the mean age of low-mass (50 km s-1) objects is only 4 Gyr. The data also suggest a large spread in age at the low-mass end of the red sequence, with 68% of the galaxies having ages between 2 and 8 Gyr. We conclude that although the stars in giant red galaxies in clusters formed early, most of the galaxies at the faint end joined the red sequence only at recent epochs. This "downsizing" trend is in good qualitative agreement with observations of the red sequence at higher redshifts but is not predicted by semianalytic models of galaxy formation

Associations between dairy cow inter-service interval and probability of conception

Recent research has indicated that the interval between inseminations in modern dairy cattle is often longer than the commonly accepted cycle length of 18–24 days. This study analysed 257,396 inseminations in 75,745 cows from 312 herds in England and Wales. The interval between subsequent inseminations in the same cow in the same lactation (inter-service interval, ISI) were calculated and inseminations categorised as successful or unsuccessful depending on whether there was a corresponding calving event. Conception risk was calculated for each individual ISI between 16 and 28 days. A random effects logistic regression model was fitted to the data with pregnancy as the outcome variable and ISI (in days) included in the model as a categorical variable. The modal ISI was 22 days and the peak conception risk was 44% for ISIs of 21 days rising from 27% at 16 days. The logistic regression model revealed significant associations of conception risk with ISI as well as 305 day milk yield, insemination number, parity and days in milk. Predicted conception risk was lower for ISIs of 16, 17 and 18 days and higher for ISIs of 20, 21 and 22 days compared to 25 day ISIs. A mixture model was specified to identify clusters in insemination frequency and conception risk for ISIs between 3 and 50 days. A “high conception risk, high insemination frequency” cluster was identified between 19 and 26 days which indicated that this time period was the true latent distribution for ISI with optimal reproductive outcome. These findings suggest that the period of increased numbers of inseminations around 22 days identified in existing work coincides with the period of increased probability of conception and therefore likely represents true return estrus events