IRAS 19135+3937: An SRd variable as interacting binary surrounded by a circumbinary disc

Semi-regular (SR) variables are not a homogeneous class and their variability is often explained due to pulsations and/or binarity. This study focuses on IRAS 19135+3937, an SRd variable with an infra-red excess indicative of a dusty disc. A time-series of high-resolution spectra, UBV photometry as well as a very accurate light curve obtained by the Kepler satellite, allowed us to study the object in unprecedented detail. We discovered it to be a binary with a period of 127 days. The primary has a low surface gravity and an atmosphere depleted in refractory elements. This combination of properties unambiguously places IRAS 19135+3937 in the subclass of post-Asymptotic Giant Branch stars with dusty discs. We show that the light variations in this object can not be due to pulsations, but are likely caused by the obscuration of the primary by the circumbinary disc during orbital motion. Furthermore, we argue that the double-peaked Fe emission lines provide evidence for the existence of a gaseous circumbinary Keplerian disc inside the dusty disc. A secondary set of absorption lines has been detected near light minimum, which we attribute to the reflected spectrum of the primary on the disc wall, which segregates due to the different Doppler shift. This corroborates the recent finding that reflection in the optical by this type of discs is very efficient. The system also shows a variable Halpha profile indicating a collimated outflow originating around the companion. IRAS 19135+3937 thus encompasses all the major emergent trends about evolved disc systems, that will eventually help to place these objects in the evolutionary context.Comment: Accepted to MNRA

Entanglement dynamics of two qubits under the influence of external kicks and Gaussian pulses

We have investigated the dynamics of entanglement between two spin-1/2 qubits that are subject to independent kick and Gaussian pulse type external magnetic fields analytically as well as numerically. Dyson time ordering effect on the dynamics is found to be important for the sequence of kicks. We show that "almost-steady" high entanglement can be created between two initially unentangled qubits by using carefully designed kick or pulse sequences

Reduced binding of human antibodies to cells from GGTA1/CMAH KO pigs

Xenotransplantation using genetically modified pig organs could solve the donor organ shortage problem. Two inactivated genes that make humans unique from pigs are GGTA1 and CMAH, the products of which produce the carbohydrate epitopes, aGal and Neu5Gc that attract preformed human antibody. When the GGTA1 and CMAH genes were deleted in pigs, human antibody binding was reduced in preliminary analysis. We analyzed the binding of human IgM and IgG from 121 healthy human serum samples for binding to GGTA1 KO and GGTA1/CMAH KO peripheral blood mononuclear cells (PBMCs). We analyzed a sub population for reactivity toward genetically modified pig PBMCs as compared to chimpanzee and human PBMCs. Deletion of the GGTA1 and CMAH genes in pigs improved the crossmatch results beyond those observed with chimpanzees. Sorting the 121 human samples tested against the GGTA1/CMAH KO pig PBMCs did not reveal a distinguishing feature such as blood group, age or gender. Modification of genes to make pig carbohydrates more similar to humans has improved the crossmatch with human serum significantly