Is the late near-infrared bump in short-hard GRB 130603B due to the Li-Paczynski kilonova?

Short-hard gamma-ray bursts (GRBs) are widely believed to be produced by the merger of two binary compact objects, specifically by two neutron stars or by a neutron star orbiting a black hole. According to the Li-Paczynski kilonova model, the merger would launch sub-relativistic ejecta and a near-infrared/optical transient would then occur, lasting up to days, which is powered by the radioactive decay of heavy elements synthesized in the ejecta. The detection of a late bump using the {\em Hubble Space Telescope} ({\em HST}) in the near-infrared afterglow light curve of the short-hard GRB 130603B is indeed consistent with such a model. However, as shown in this Letter, the limited {\em HST} near-infrared lightcurve behavior can also be interpreted as the synchrotron radiation of the external shock driven by a wide mildly relativistic outflow. In such a scenario, the radio emission is expected to peak with a flux of $\sim 100 \mu$Jy, which is detectable for current radio arrays. Hence, the radio afterglow data can provide complementary evidence on the nature of the bump in GRB 130603B. It is worth noting that good spectroscopy during the bump phase in short-hard bursts can test validity of either model above, analogous to spectroscopy of broad-lined Type Ic supernova in long-soft GRBs.Comment: 4 pages, 2 figures, published in ApJ Lette

Manual small incision combined with negative power intraocular lens implantation for cataract with high myopia clinical observation

AIM: To evaluate the clinical effect of manual small incision combined with negative power intraocular lens implantation for cataract with high myopia. <p>METHODS: Totally 75 cases(98 eyes)with super high myopia and cataract which had underwent small incision combined with negative power intraocular lens implantation were studied retrospectively. Preoperative axial length and postoperative visual acuity, refractive diopter and expected deviation value(refractive deviation)were recorded. Eye conditions operation complications and postoperative were observed. The patients were followed-up for 6 to 12 months. <p>RESULTS: The mean preoperative axial length was 32.05±1.78mm. Best corrected visual acuity≥0.2 was in 66 eyes, accounting for 67.3%; ≥0.5 in 43 eyes, accounting for 43.9%; the postoperative refractive error <±1.00D was total 48 eyes, accounting for 49.0%; <±2.00D total 78 eyes, accounting for 79.6%. Intra-operative posterior capsular rupture occurred in 3 eyes. Intra-operative posterior elastic layer detachment occurred in 1 cases. The postoperative corneal edema was found in 21 eyes. Postoperative 6 months, posterior capsular opacification was found in 13 eyes, and the visual acuity recovered after Nd:YAG laser cut. No retinal detachment, secondary glaucoma, macular cystoid edema, intraocular lens shift and other complications were found. Two eyes had the symptom of binocular interference post-operation. Three months later, another eye was performed intraocular lens implantation. The symptoms were eliminated post-operation. <p>CONCLUSION: The manual small incision cataract extraction combined with negative power intraocular lens implantation for cataract with high myopia is safe, effective method