Defining an action of ()-rotations on images generated by projections of -dimensional objects: Applications to pose inference with Geometric VAEs.

Recent advances in variational autoencoders (VAEs) have enabled learning latent manifolds as compact Lie groups, such as (). Since this approach assumes that data lies on a subspace that is homeomorphic to the Lie group itself, we here investigate how this assumption holds in the context of images that are generated by projecting a -dimensional volume with unknown pose in (). Upon examining different theoretical candidates for the group and image space, we show that the attempt to define a group action on the data space generally fails, as it requires more specific geometric constraints on the volume.

Loss of MyoD and Myf5 in Skeletal Muscle Stem Cells Results in Altered Myogenic Programming and Failed Regeneration.

MyoD and Myf5 are fundamental regulators of skeletal muscle lineage determination in the embryo, and their expression is induced in satellite cells following muscle injury. MyoD and Myf5 are also expressed by satellite cell precursors developmentally, although the relative contribution of historical and injury-induced expression to satellite cell function is unknown. We show that satellite cells lacking both MyoD and Myf5 (double knockout [dKO]) are maintained with aging in uninjured muscle.

Activin-dependent signaling in fibro/adipogenic progenitors causes fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal-dominant disorder characterized by progressive and profoundly disabling heterotopic ossification (HO). Here we show that fibro/adipogenic progenitors (FAPs) are a major cell-of-origin of HO in an accurate genetic mouse model of FOP (Acvr1 ). Targeted expression of the disease-causing type I bone morphogenetic protein (BMP) receptor, ACVR1(R206H), to FAPs recapitulates the full spectrum of HO observed in FOP patients.

Emergency department diagnosis and management of skin diseases with real-time teledermatologic expertise.

Importance: Skin conditions are a common reason for patients to consult emergency department (ED) physicians.

Objective: To evaluate real-time teledermatologic expertise with the use of mobile telephones for the diagnosis and management of skin conditions in patients seen in the ED.

Design, Setting, And Participants: This observational study of adults who consecutively consulted in the ED for a dermatologic condition was conducted under routine conditions in the ED from May 1, 2008, through June 30, 2010.