Constraints on cosmic strings using data from the first Advanced LIGO observing run

Cosmic strings are topological defects which can be formed in grand unified theory scale phase transitions in the early universe. They are also predicted to form in the context of string theory. The main mechanism for a network of Nambu-Goto cosmic strings to lose energy is through the production of loops and the subsequent emission of gravitational waves, thus offering an experimental signature for the existence of cosmic strings. Here we report on the analysis conducted to specifically search for gravitational-wave bursts from cosmic string loops in the data of Advanced LIGO 2015-2016 observing run (O1). No evidence of such signals was found in the data, and as a result we set upper limits on the cosmic string parameters for three recent loop distribution models. In this paper, we initially derive constraints on the string tension Gμ and the intercommutation probability, using not only the burst analysis performed on the O1 data set but also results from the previously published LIGO stochastic O1 analysis, pulsar timing arrays, cosmic microwave background and big-bang nucleosynthesis experiments. We show that these data sets are complementary in that they probe gravitational waves produced by cosmic string loops during very different epochs. Finally, we show that the data sets exclude large parts of the parameter space of the three loop distribution models we consider

Aneurysmal bone cyst of the spine: Management and outcome

Study Design. The clinical records, radiographs, histologic sections, and operative reports of 52 consecutive patients with an aneurysmal bone cyst of the spine were reviewed to evaluate diagnostic and therapeutic options and to correlate treatment and outcome. Objectives. To define the incidence, clinical presentation, diagnostic and therapeutic options, and prognosis of patients with aneurysmal bone cyst of the spine. Summary of Background Data. There are special considerations in the management of spinal lesions: relative inaccessibility of the lesions, associated intraoperative bleeding, necessary of removing the entire lesion to avoid the possibility of recurrence proximity of the lesion to the spinal cord and nerve roots, and potential postoperative bony spinal instability. Methods. Fifty-two consecutive patients with an aneurysmal bone cyst of the spine were treated from 1910 to 1993. Forty patients initially treated for a primary lesion had operative treatment (19 intralesional excision and bone grafting and 21 intralesional excision), four also had adjuvant radiation therapy. Preoperative arterial embolization was performed in two. Results. There was a recurrence rate of 10% within 10 years. All recurrences were noted less than 6 months after surgery. Of 12 patients treated for a recurrent lesion two had a subsequent recurrence (16.7%) within 9 years. At last follow up examination, 50 patients (96%) were free of the disease. One patient died of postradiation osteosarcoma, and one died of intraoperative bleeding. Conclusion. Current treatment recommendations involved preoperative selective arterial embolization, intralesional excision curettage, bone grafting, and fusion of the affected area if instability is present