MITOCHONDRIAL DNA POLYMORPHISMS AND FERTILITY IN BEEF CATTLE

Two regions of mitochondrial DNA, D-loop and ND-5 were characterized using polymerase chain reaction – restriction fragment length polymorphism (PCR-RFLP) involving 422 beef cattle of Hereford and composite breeds from Wokalup’s research station. ANOVA models (model I, II) were used to estimate associations between molecular haplotypes and quantitative traits. The phenotypic data used were records on calving rate, defined as the mean number of live calves born over four years, while the genotypic data used were the result of PCR-RFLP analysis in both regions of mitochondrial DNA using 7 restriction enzymes. The results of the present study have provided evidence that mitochondrial polymorphisms in the D-loop and ND-5 regions are associated significantly with fertility. This is the first report of a correlation between mitochondrial polymorphism in D-loop and ND-5 on fertility in beef cattle. Key words: PCR-RFLP, bovine mitochondrial DNA, D-loop, ND-5

Global Dynamics of Subsurface Solar Active Regions

We present three-dimensional numerical simulations of a magnetic loop evolving in either a convectively stable or unstable rotating shell. The magnetic loop is introduced in the shell in such a way that it is buoyant only in a certain portion in longitude, thus creating an \Omega-loop. Due to the action of magnetic buoyancy, the loop rises and develops asymmetries between its leading and following legs, creating emerging bipolar regions whose characteristics are similar to the ones of observed spots at the solar surface. In particular, we self-consistently reproduce the creation of tongues around the spot polarities, which can be strongly affected by convection. We moreover emphasize the presence of ring-shaped magnetic structures around our simulated emerging regions, which we call "magnetic necklace" and which were seen in a number of observations without being reported as of today. We show that those necklaces are markers of vorticity generation at the periphery and below the rising magnetic loop. We also find that the asymmetry between the two legs of the loop is crucially dependent on the initial magnetic field strength. The tilt angle of the emerging regions is also studied in the stable and unstable cases and seems to be affected both by the convective motions and the presence of a differential rotation in the convective cases.Comment: 23 pages (ApJ 2-column format), 19 figures, accepted for publication in Ap

Triggering an eruptive flare by emerging flux in a solar active-region complex

A flare and fast coronal mass ejection originated between solar active regions NOAA 11514 and 11515 on July 1, 2012 in response to flux emergence in front of the leading sunspot of the trailing region 11515. Analyzing the evolution of the photospheric magnetic flux and the coronal structure, we find that the flux emergence triggered the eruption by interaction with overlying flux in a non-standard way. The new flux neither had the opposite orientation nor a location near the polarity inversion line, which are favorable for strong reconnection with the arcade flux under which it emerged. Moreover, its flux content remained significantly smaller than that of the arcade (approximately 40 %). However, a loop system rooted in the trailing active region ran in part under the arcade between the active regions, passing over the site of flux emergence. The reconnection with the emerging flux, leading to a series of jet emissions into the loop system, caused a strong but confined rise of the loop system. This lifted the arcade between the two active regions, weakening its downward tension force and thus destabilizing the considerably sheared flux under the arcade. The complex event was also associated with supporting precursor activity in an enhanced network near the active regions, acting on the large-scale overlying flux, and with two simultaneous confined flares within the active regions.Comment: Accepted for publication in Topical Issue of Solar Physics: Solar and Stellar Flares. 25 pages, 12 figure

Nonlinear Force-Free Magnetic Field Fitting to Coronal Loops with and without Stereoscopy

We developed a new nonlinear force-free magnetic field (NLFFF) forward-fitting algorithm based on an analytical approximation of force-free and divergence-free NLFFF solutions, which requires as input a line-of-sight magnetogram and traced 2D loop coordinates of coronal loops only, in contrast to stereoscopically triangulated 3D loop coordinates used in previous studies. Test results of simulated magnetic configurations and from four active regions observed with STEREO demonstrate that NLFFF solutions can be fitted with equal accuracy with or without stereoscopy, which relinquishes the necessity of STEREO data for magnetic modeling of active regions (on the solar disk). The 2D loop tracing method achieves a 2D misalignment of $\mu_2=2.7^\circ\pm 1.3^\circ$ between the model field lines and observed loops, and an accuracy of $\approx 1.0$ for the magnetic energy or free magnetic energy ratio. The three times higher spatial resolution of TRACE or SDO/AIA (compared with STEREO) yields also a proportionally smaller misalignment angle between model fit and observations. Visual/manual loop tracings are found to produce more accurate magnetic model fits than automated tracing algorithms. The computation time of the new forward-fitting code amounts to a few minutes per active region.Comment: ApJ, Febr 2013, (in press), 11 Figure

Physical Conditions in Barnard's Loop, Components of the Orion-Eridanus Bubble, and Implications for the WIM Component of the ISM

We have supplemented existing spectra of Barnard's Loop with high accuracy spectrophotometry of one new position. Cloudy photoionization models were calculated for a variety of ionization parameters and stellar temperatures and compared with the observations. After testing the procedure with recent observations of M43, we establish that Barnard's Loop is photoionized by four candidate ionizing stars, but agreement between the models and observations is only possible if Barnard's Loop is enhanced in heavy elements by about a factor of 1.4. Barnard's Loop is very similar in properties to the brightest components of the Orion-Eridanus Bubble and the Warm Ionized Medium (WIM). We are able to establish models that bound the range populated in low-ionization color-color diagrams (I([SII])/I(H{\alpha}) versus I([NII])/I(H{\alpha})) using only a limited range of ionization parameters and stellar temperatures. Previously established variations in the relative abundance of heavy elements render uncertain the most common method of determining electron temperatures for components of the Orion-Eridanus Bubble and the WIM based on only the I([NII])/I(H{\alpha}) ratio, although we confirm that the lowest surface brightness components of the WIM are on average of higher electron temperature. The electron temperatures for a few high surface brightness WIM components determined by direct methods are comparable to those of classical bright H II regions. In contrast, the low surface brightness HII regions studied by the Wisconsin H{\alpha} Mapper are of lower temperatures than the classical bright HII regions

Coronal rain in magnetic bipolar weak fields

We intend to investigate the underlying physics for the coronal rain phenomenon in a representative bipolar magnetic field, including the formation and the dynamics of coronal rain blobs. With the MPI-AMRVAC code, we performed three dimensional radiative magnetohydrodynamic (MHD) simulation with strong heating localized on footpoints of magnetic loops after a relaxation to quiet solar atmosphere. Progressive cooling and in-situ condensation starts at the loop top due to radiative thermal instability. The first large-scale condensation on the loop top suffers Rayleigh-Taylor instability and becomes fragmented into smaller blobs. The blobs fall vertically dragging magnetic loops until they reach low beta regions and start to fall along the loops from loop top to loop footpoints. A statistic study of the coronal rain blobs finds that small blobs with masses of less than 10^10 g dominate the population. When blobs fall to lower regions along the magnetic loops, they are stretched and develop a non-uniform velocity pattern with an anti-parallel shearing pattern seen to develop along the central axis of the blobs. Synthetic images of simulated coronal rain with Solar Dynamics Observatory Atmospheric Imaging Assembly well resemble real observations presenting dark falling clumps in hot channels and bright rain blobs in a cool channel. We also find density inhomogeneities during a coronal rain "shower", which reflects the observed multi-stranded nature of coronal rain.Comment: 8 figure

Properties of the Acceleration Regions in Several Loop-structured Solar Flares

Using {\em RHESSI} hard X-ray imaging spectroscopy observations, we analyze electron flux maps for a number of extended coronal loop flares. For each event, we fit a collisional model with an extended acceleration region to the observed variation of loop length with electron energy $E$, resulting in estimates of the plasma density in, and longitudinal extent of, the acceleration region. These quantities in turn allow inference of the number of particles within the acceleration region and hence the filling factor $f$ -- the ratio of the emitting volume to the volume that encompasses the emitting region(s). We obtain values of $f$ that lie mostly between 0.1 and 1.0; the (geometric) mean value is $f = 0.20 \times \div 3.9$, somewhat less than, but nevertheless consistent with, unity. Further, coupling information on the number of particles in the acceleration region with information on the total rate of acceleration of particles above a certain reference energy (obtained from spatially-integrated hard X-ray data) also allows inference of the specific acceleration rate (electron s$^{-1}$ per ambient electron above the chosen reference energy). We obtain a (geometric) mean value of the specific acceleration rate $\eta(20$ keV) $= (6.0 \times / \div 3.4) \times 10^{-3}$ electrons s$^{-1}$ per ambient electron; this value has implications both for the global electrodynamics associated with replenishment of the acceleration region and for the nature of the particle acceleration process