Paired-End Mappability of Transposable Elements in the Human Genome

Though transposable elements make up around half of the human genome, the repetitive nature of their sequences makes it difficult to accurately align conventional sequencing reads. However, in light of new advances in sequencing technology, such as increased read length and paired-end libraries, these repetitive regions are now becoming easier to align to. This study investigates the mappability of transposable elements with 50 bp, 76 bp and 100 bp paired-end read libraries. With respect to those read lengths and allowing for 3 mismatches during alignment, over 68, 85, and 88% of all transposable elements in the RepeatMasker database are uniquely mappable, suggesting that accurate locus-specific mapping of older transposable elements is well within reach

Sparticle Production in Electron-Photon Collisions

We explore the potential of electron-photon colliders to measure fundamental supersymmetry parameters via the processes $e\gamma \to \tilde e \tilde\chi^0$ (selectron-neutralino) and $e\gamma\to \tilde\nu \tilde\chi^-$ (sneutrino-chargino). Given the $\tilde\chi^0$ and $\tilde\chi^-$ masses from $e^+e^-$ and hadron collider studies, cross section ratios $\sigma(\gamma_-)/\sigma(\gamma_+)$ for opposite photon helicities determine the $\tilde\nu_L$, $\tilde e_L$ and $\tilde e_R$ masses, independent of the sparticle branching fractions. The difference $m_{\tilde\nu_L}^2-m_{\tilde e_L}^2$ measures $M_W^2\cos2\beta$ in a model-independent way. The $\tilde e_L$ and $\tilde e_R$ masses test the universality of soft supersymmetry breaking scalar masses. The cross section normalizations provide information about the gaugino mixing parameters.Comment: add refs; add \tightenline

Strong spin-orbit coupling and magnetism in (111) (La0.3_{0.3}Sr0.7_{0.7})(Al0.65_{0.65}Ta0.35)_{0.35})/SrTiO3_3

Strong correlations, multiple lattice degrees of freedom, and the ease of doping make complex oxides a source of great research interest. Complex oxide heterointerfaces break inversion symmetry and can host a two dimensional carrier gas, which can display a variety of coexisting and competing phenomena. In the case of heterointerfaces based on SrTiO$_3$, many of these phenomena can be effectively tuned by using an electric gate, due to the large dielectric constant of SrTiO$_3$. Most studies so far have focused on (001) oriented heterostructures; however, (111) oriented heterostructures have recently gained attention due to the possibility of finding exotic physics in these systems due their hexagonal surface crystal symmetry. In this work, we use magnetoresistance to study the evolution of spin-orbit interaction and magnetism in a new system, (111) oriented (La$_{0.3}$Sr$_{0.7}$)(Al$_{0.65}$Ta$_{0.35}$)/SrTiO$_3$. At more positive values of the gate voltage, which correspond to high carrier densities, we find that transport is multiband, and dominated by high mobility carriers with a tendency towards weak localization. At more negative gate voltages, the carrier density is reduced, the high mobility bands are depopulated, and weak antilocalization effects begin to dominate, indicating that spin-orbit interaction becomes stronger. At millikelvin temperatures, and gate voltages corresponding to the strong spin-orbit regime, we observe hysteresis in magnetoresistance, indicative of ferromagnetism in the system. Our results suggest that in the (111) (La$_{0.3}$Sr$_{0.7}$)(Al$_{0.65}$Ta$_{0.35}$)/SrTiO$_3$ system, low mobility carriers which experience strong spin-orbit interactions participate in creating magnetic order in the system.Comment: 15 pages, 3 figure

Properties of Planetary Caustics in Gravitational Microlensing

Although some of the properties of the caustics in planetary microlensing have been known, our understanding of them is mostly from scattered information based on numerical approaches. In this paper, we conduct a comprehensive and analytic analysis of the properties of the planetary caustics, which are one of the two sets of caustics in planetary microlensing, those located away from the central star. Under the perturbative approximation, we derive analytic expressions for the location, size, and shape of the planetary caustic as a function of the star-planet separation and the planet/star mass ratio. Based on these expressions combined with those for the central caustic, which is the other set of caustics located close to the central star, we compare the similarities and differences between the planetary and central caustics. We also present the expressions for the size ratio between the two types of caustics and for the condition of the merging of the two types of caustics. These analytic expressions will be useful in understanding the dependence of the planetary lensing behavior on the planet parameters and thus in interpreting the planetary lensing signalsComment: total 6 pages, including 6 figures, ApJ, submitte