Paraspinal Transposition Flap for Reconstruction of Sacral Soft Tissue Defects: A Series of 53 Cases from a Single Institute

Study DesignCase series.PurposeTo describe paraspinal transposition flap for coverage of sacral soft tissue defects.Overview of LiteratureSoft tissue defects in the sacral region pose a major challenge to the reconstructive surgeon. Goals of sacral wound reconstruction are to provide a durable skin and soft tissue cover adequate for even large sacral defects; minimize recurrence; and minimize donor site morbidity. Various musculocutaneous and fasciocutanous flaps have been described in the literature.MethodsThe flap was applied in 53 patients with sacral soft tissue defects of diverse etiology. Defects ranged in size from small (6 cm×5 cm) to extensive (21 cm×10 cm). The median age of the patients was 58 years (range, 16-78 years).ResultsThere was no flap necrosis. Primary closure of donor sites was possible in all the cases. The median follow up of the patients was 33 months (range, 4-84 months). The aesthetic outcomes were acceptable. There has been no recurrence of pressure sores.ConclusionsThe authors conclude that paraspinal transposition flap is suitable for reconstruction of large sacral soft tissue defects with minimum morbidity and excellent long term results

GWTC-2.1: Deep extended catalog of compact binary coalescences observed by LIGO and Virgo during the first half of the third observing run

The second Gravitational-Wave Transient Catalog, GWTC-2, reported on 39 compact binary coalescences observed by the Advanced LIGO and Advanced Virgo detectors between 1 April 2019 15:00 UTC and 1 October 2019 15:00 UTC. Here, we present GWTC-2.1, which reports on a deeper list of candidate events observed over the same period. We analyze the final version of the strain data over this period with improved calibration and better subtraction of excess noise, which has been publicly released. We employ three matched-filter search pipelines for candidate identification, and estimate the probability of astrophysical origin for each candidate event. While GWTC-2 used a false alarm rate threshold of 2 per year, we include in GWTC-2.1, 1201 candidates that pass a false alarm rate threshold of 2 per day. We calculate the source properties of a subset of 44 high-significance candidates that have a probability of astrophysical origin greater than 0.5. Of these candidates, 36 have been reported in GWTC-2. We also calculate updated source properties for all binary block hole events previously reported in GWTC-1. If the 8 additional high-significance candidates presented here are astrophysical, the mass range of events that are unambiguously identified as binary black holes (both objects \geq 3M_\odot) is increased compared to GWTC-2, with total masses from \sim 14M_\odot for GW190924_021846 to \sim 182M_\odot for GW190426_190642. Source properties calculated using our default prior suggest that the primary components of two new candidate events (GW190403_051519 and GW190426_190642) fall in the mass gap predicted by pair-instability supernova theory. We also expand the population of binaries with significantly asymmetric mass ratios reported in GWTC-2 by an additional two events (the mass ratio is less than 0.65 and 0.44 at 90% probability for GW190403_051519 and GW190917_114630 respectively), and find that 2 of the 8 new events have effective inspiral spins \chi_\mathrm{eff} > 0 (at 90\% credibility), while no binary is consistent with \chi_\mathrm{eff} \lt 0 at the same significance. We provide updated estimates for rates of binary black hole and binary neutron star coalescence in the local Universe

Practical method for system of systems tradespace exploration

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2009.Includes bibliographical references (p. 211-215).Systems of Systems (SoS) are a current focus of many organizations interested in integrating assets and utilizing new technology to create multi-component systems that deliver value over time. The dynamic composition of SoS along with the managerial independence of their component systems necessitates systems engineering considerations and methods beyond those of traditional systems engineering, particularly for SoS concept design. Qualitative and heuristic-based guidance is available in the literature, but there is a need for a method that will allow decision makers to quantitatively compare diverse multi-concept SoS designs on an equal basis in order to select value robust designs during concept exploration. Development of a quantitative method for SoS conceptual design will enable the consideration of many more architecture options than is possible through qualitative methods alone, facilitating a more complete exploration of a SoS design space. In this thesis, a quantitative method for SoS conceptual design, known as System of Systems Tradespace Exploration Method (SoSTEM), is presented. This method is based on the existing Dynamic Multi-Attribute Tradespace Exploration (MATE) which is a formal methodology for tradespace exploration during system design that allows the decision maker to make trades between both stakeholder preferences and systems early in the design process and includes the consideration of dynamic issues such as unarticulated stakeholder preferences and changing system context.(cont.) In SoSTEM, SoS-level performance attributes are generated through a combination of component system attributes and system latent value, allowing the generation of SoS tradespaces where multi-concept architectures can be compared on the same performance and cost basis. This method allows the SoS designer to distinguish between component systems having high likelihood of participation in the SoS and those with lower likelihood of participation, based on the level of 'Effective Managerial Authority' that the SoS designer has over the component. SoSTEM is demonstrated through application to two case studies, an Operationally Responsive System for Disaster Surveillance and Satellite Radar.by Debarati Chattopadhyay.S.M

Risk Identification and Visualization in a Concurrent Engineering Team Environment

Incorporating risk assessment into the dynamic environment of a concurrent engineering team requires rapid response and adaptation. Generating consistent risk lists with inputs from all the relevant subsystems and presenting the results clearly to the stakeholders in a concurrent engineering environment is difficult because of the speed with which decisions are made. In this paper we describe the various approaches and techniques that have been explored for the point designs of JPL's Team X and the Trade Space Studies of the Rapid Mission Architecture Team. The paper will also focus on the issues of the misuse of categorical and ordinal data that keep arising within current engineering risk approaches and also in the applied risk literature

Characterizing Distributed Concurrent Engineering Teams: A Descriptive Framework for Aerospace Concurrent Engineering Design Teams

As aerospace missions grow larger and more technically complex in the face of ever tighter budgets, it will become increasingly important to use concurrent engineering methods in the development of early conceptual designs because of their ability to facilitate rapid assessments and trades in a cost-efficient manner. To successfully accomplish these complex missions with limited funding, it is also essential to effectively leverage the strengths of individuals and teams across government, industry, academia, and international agencies by increased cooperation between organizations. As a result, the existing concurrent engineering teams will need to increasingly engage in distributed collaborative concurrent design. This paper is an extension of a recent white paper written by the Concurrent Engineering Working Group, which details the unique challenges of distributed collaborative concurrent engineering. This paper includes a short history of aerospace concurrent engineering, and defines the terms 'concurrent', 'collaborative' and 'distributed' in the context of aerospace concurrent engineering. In addition, a model for the levels of complexity of concurrent engineering teams is presented to provide a way to conceptualize information and data flow within these types of teams

Giant angioleiomyoma of knee presenting as painless ulcer: The first case report

Angioleiomyomas are benign tumors originating in the vascular smooth muscle. The tumor typically presents as painful, solitary, small (<2 cm), slow growing, subcutaneous nodule. Angioleiomyoma of the knee is rare, and only few cases have been reported so far. We have described herein a giant angioleiomyoma of the knee presenting as a painless ulcer in a 22-year-old man. There was no intra-articular extension of the tumor, and total excision was curative. This is the first case report of giant angioleiomyoma of the knee as well as the first case report of angioleiomyoma presenting as a painless ulcerative lesion