Static black hole solutions with a self interacting conformally coupled scalar field

We study static, spherically symmetric black hole solutions of the Einstein equations with a positive cosmological constant and a conformally coupled self interacting scalar field. Exact solutions for this model found by Mart{\'\i}nez, Troncoso, and Zanelli, (MTZ), were subsequently shown to be unstable under linear perturbations, with modes that diverge arbitrarily fast. We find that the moduli space of static, spherically symmetric solutions that have a regular horizon -and satisfy the weak and dominant energy conditions outside the horizon- is a singular subset of a two dimensional space parameterized by the horizon radius and the value of the scalar field at the horizon. The singularity of this space of solutions provides an explanation for the instability of the MTZ spacetimes, and leads to the conclusion that, if we include stability as a criterion, there are no physically acceptable black hole solutions for this system that contain a cosmological horizon in the exterior of its event horizon.Comment: 22 pages, 5 figures (replaced figure #4), final version, to be published in PR

Duality between simple-group gauge theories and some applications

In this paper we investigate N=1 supersymmetric gauge theories with a product gauge group. By using smoothly confining dynamics, we can find new dualities which include higher-rank tensor fields, and in which the dual gauge group is simple, not a product. Some of them are dualities between chiral and non-chiral gauge theories. We also discuss some applications to dynamical supersymmetry breaking phenomena and new confining theories with a tree-level superpotential.Comment: 33 pages, LaTeX, references added, version to appear in PR

Axonal and dendritic endocytic pathways in cultured neurons

The endocytic pathways from the axonal and dendritic surfaces of cultured polarized hippocampal neurons were examined. The dendrites and cell body contained extensive networks of tubular early endosomes which received endocytosed markers from the somatodendritic domain. In axons early endosomes were confined to presynaptic terminals and to varicosities. The somatodendritic but not the presynaptic early endosomes were labeled by internalized transferrin. In contrast to early endosomes, late endosomes and lysosomes were shown to be predominantly located in the cell body. Video microscopy was used to follow the transport-t of internalized markers from the periphery of axons and dendrites back to the cell body. Labeled structures in both domains moved unidirectionally by retrograde fast transport. Axonally transported organelles were sectioned for EM after video microscopic observation and shown to be large multivesicular body-like structures. Similar structures accumulated at the distal side of an axonal lesion. Multivesicular bodies therefore appear to be the major structures mediating transport of endocytosed markers between the nerve terminals and the cell body. Late endocytic structures were also shown to be highly mobile and were observed moving within the cell body and proximal dendritic segments. The results show that the organization of the endosomes differs in the axons and dendrites of cultured rat hippocampal neurons and that the different compartments or stages of the endocytic pathways can be resolved spatially

Hyperk\"ahler torsion structures invariant by nilpotent Lie groups

We study HKT structures on nilpotent Lie groups and on associated nilmanifolds. We exhibit three weak HKT structures on $\R^8$ which are homogeneous with respect to extensions of Heisenberg type Lie groups. The corresponding hypercomplex structures are of a special kind, called abelian. We prove that on any 2-step nilpotent Lie group all invariant HKT structures arise from abelian hypercomplex structures. Furthermore, we use a correspondence between abelian hypercomplex structures and subspaces of ${\frak sp}(n)$ to produce continuous families of compact and noncompact of manifolds carrying non isometric HKT structures. Finally, geometrical properties of invariant HKT structures on 2-step nilpotent Lie groups are obtained.Comment: LateX, 12 page

Probing the nature of the massive black hole binary candidate SDSS J1536+0441

We present an imaging study of the black hole binary candidate SDSS J1536+0441 (z=0.3893), based on deep, high resolution VzK images collected at the ESO/VLT. The images clearly show an asymmetric elongation, indicating the presence of a companion source at ~1" (~5 kpc projected distance) East from the quasar. The host galaxy of the quasar is marginally resolved. We find that the companion source is a luminous galaxy, the light profile of which suggests the presence of an unresolved, faint nucleus (either an obscured AGN or a compact stellar bulge). The study of the environment around the quasar indicates the occurrence of a significant over-density of galaxies with a redshift compatible with z~0.4. This suggests that it resides in a moderately rich cluster of galaxies.Comment: 4 figures, 1 table. Accepted for publication in ApJ Letter

New Confining N=1 Supersymmetric Gauge Theories

We examine N=1 supersymmetric gauge theories which confine in the presence of a tree-level superpotential. We show the confining spectra which satisfy the 't Hooft anomaly matching conditions and give a simple method to find the confining superpotential. Using this method we fix the confining superpotentials in the simplest cases, and show how these superpotentials are generated by multi-instanton effects in the dual theory. These new type of confining theories may be useful for model building, since the size of the matter content is not restricted by an index constraint. Therefore, one expects that a large variety of new confining spectra can be obtained using such models.Comment: 26 pages, LaTe

Nocodazole-Dependent Transport, and Brefeldin A-Sensitive Processing and Sorting, of Newly Synthesized Membrane-Proteins in Cultured Neurons

The envelope glycoproteins of Semliki Forest virus (SFV), Vesicular Stomatitis virus (VSV), and Influenza Fowl Plague virus (FPV) are vectorially targeted in neurons to the plasma membrane of dendrites (SFV and VSV) and axons (FPV), To gain insight into the mechanisms responsible for such polarized delivery we have examined the effects on neurons of nocodazole and brefeldin A (BFA), which are known to cause microtubule depolymerization and disassembly of the Golgi apparatus, respectively, Nocodazole treatment blocked transport of all viral glycoproteins to both axons and dendrites, BFA treatment induced disruption of the Golgi complex, including the trans-Golgi network (TGN), and tubulation of endosomes, However, the delivery of the SFV and FPV glycoproteins to the cell surface was not affected significantly by BFA, although processing and sorting were altered as revealed by surface biotinylation and immunofluorescence microscopy of fixed nonpermeabilized cells, These results demonstrate the involvement of microtubules in axonal and dendritic transport of integral membrane glycoproteins, and the existence of a BFA-sensitive component in the sorting but not in the transport machinery

Supersymmetric Gauge Theories with an Affine Quantum Moduli Space

All supersymmetric gauge theories based on simple groups which have an affine quantum moduli space, i.e. one generated by gauge invariants with no relations, W=0, and anomaly matching at the origin, are classified. It is shown that the only theories with no gauge invariants (and moduli space equal to a single point) are the two known examples, SU(5) with 5-bar + 10 and SO(10) with a spinor. The index of the matter representation must be at least as big as the index of the adjoint in theories which have a non-trivial relation among the gauge invariants.Comment: Incorrect proof that theories with constraints must have mu >= mu(adj) replaced by a correct one (6 pages, uses revtex, amssymb, array

pH-induced microtubule-dependent redistribution of late endosomes in neuronal and epithelial cells

The interaction between late endocytic structures and microtubules in polarized cells was studied using a procedure previously shown to cause microtubule-dependent redistribution of lysosomes in fibroblasts and macrophages (Heuser, J. 1989. J. Cell Biol. 108:855-864). In cultured rat hippocampal neurons, low cytoplasmic pH caused cation-independent mannose-6-phosphate receptor-enriched structures to move out of the cell body and into the processes. In filter grown MDCK cells lowering the cytosolic pH to approximately 6.5 caused late endosomes to move to the base of the cell and this process was shown to be microtubule dependent. Alkalinization caused a shift in distribution towards the apical pole of the cell. The results are consistent with low pH causing the redistribution of late endosomes towards the plus ends of the microtubules. In MDCK cells the microtubules orientated vertically in the cell may play a role in this process. The shape changes that accompanied the redistribution of the late endosomes in MDCK cells were examined by electron microscopy. On low pH treatment fragmentation of the late endosomes was observed whereas after microtubule depolymerization individual late endosomal structures appeared to fuse together. The late endosomes of the MDCK cell appear to be highly pleomorphic and dependent on microtubules for their form and distribution in the cell

Combining oncolytic viruses with chimeric antigen receptor T cell therapy

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of hematological malignancies, but solid tumors continue to pose significant challenges. Oncolytic viruses (OVs) have generated significant excitement in the field of cancer treatment recently. In particular, OVs can help CAR T cells overcome some of the immunosuppressive mechanisms within the tumor microenvironment through OV intrinsic effects or delivery of immunostimulatory agents. Numerous preclinical studies demonstrate that combining CAR T cells with OVs can increase CAR T cell trafficking, antitumor activity, and elimination of antigen-negative tumor cells. Despite promising preclinical results, only one clinical trial (NCT03740256) investigating CAR T and OV combination therapy is underway, highlighting the challenges of translating this approach to the clinic. Antiviral immunity and the route of OV administration, in addition to concerns about cost and safety, limit the clinical application of this approach. Strategies to reduce the production cost of both CAR T cells and OVs, as well as molecularly modifying OVs to enhance their bioavailability, will likely encourage further exploration of this combination therapy in clinical trials