We use rational formality of configuration spaces and the bar construction to study the cohomology of the space of braids in dimension four or greater. We provide a diagram complex for braids and a quasi-isomorphism to the de Rham cochains on the space of braids. The quasi-isomorphism is given by a configuration space integral followed by Chen’s iterated integrals. This extends results of Kohno and of Cohen and Gitler on the cohomology of the space of braids to a commutative differential graded algebra suitable for integration. We show that this integration is compatible with Bott–Taubes configuration space integrals for long links via a map between two diagram complexes. As a corollary, we get a surjection in cohomology from the space of long links to the space of braids. We also discuss to what extent our results apply to the case of classical braids.

We used participatory design methodology to engage independently living older adults with depression and co-occurring physical illness in the design of assistive robots for their homes. Our aim was to work toward a design that can extend the amount of time they can live independently and increase their quality of life. Clinicians were also invited to contribute their ideas, as they are important advocates for using assistive technology in a clinical capacity. In this paper, we outline our strategies for engaging older adults as co-designers, noting what succeeded and what failed in our participatory design approach. We also discuss the viability of replication studies in participatory design and the need to engage other stakeholders besides older adults, such as clinicians, to provide practical robot applications.

Abstract This video demonstrates microsurgical resection of spinal cord hemangioblastoma. Hemangioblastomas are rare, benign, highly vascularized tumors classified as grade I according to World Health Organization classification systems. About 3% of all intramedullary tumors are hemangioblastomas.1,2 Spinal cord hemangioblastomas are either sporadic3,4 or manifestations of von Hippel-Lindau (VHL) disease in 20% to 45% of patients.5,6  A 30-year-old male presented with sudden onset urinary incontinence. Magnetic resonance imaging showed contrast enhancing intramedullary tumor with adjacent cyst in T11, and syringomyelia extending to C1. Surgical resection followed rules that apply to resection of arteriovascular malformations: coagulation of arterial feeders precedes the coagulation of the draining vein, which is preserved until the end of surgery.2,4,5,7,8  First, posterior midline myelotomy was performed and the tumor cyst was drained in order to develop a dissection plane. Following this, we continuously separated dorsal nerve roots from the tumor nodule using microsurgical technique. The key step in tumor resection is devascularization of the tumor, achievable in 2 ways.2,7,9-13 The circumferential detachment of the normal pia from the tumor pia is crucial in developing a plane of dissection. The coagulation and division of arterial feeders while preserving the drainage vein further devascularizes the tumor. Once the tumor mural nodule was detached from the spinal cord, the drainage vein was coagulated last and the tumor was removed. The patient fully recovered from his incontinence and was neurologically intact. Screening for VHL disease was negative.  Written consent was obtained directly from the patient.