Deriving percentage study weights in multi-parameter meta-analysis models: with application to meta-regression, network meta-analysis and one-stage individual participant data models.

Many meta-analysis models contain multiple parameters, for example due to multiple outcomes, multiple treatments or multiple regression coefficients. In particular, meta-regression models may contain multiple study-level covariates, and one-stage individual participant data meta-analysis models may contain multiple patient-level covariates and interactions. Here, we propose how to derive percentage study weights for such situations, in order to reveal the (otherwise hidden) contribution of each study toward the parameter estimates of interest. We assume that studies are independent, and utilise a decomposition of Fisher's information matrix to decompose the total variance matrix of parameter estimates into study-specific contributions, from which percentage weights are derived. This approach generalises how percentage weights are calculated in a traditional, single parameter meta-analysis model. Application is made to one- and two-stage individual participant data meta-analyses, meta-regression and network (multivariate) meta-analysis of multiple treatments. These reveal percentage study weights toward clinically important estimates, such as summary treatment effects and treatment-covariate interactions, and are especially useful when some studies are potential outliers or at high risk of bias. We also derive percentage study weights toward methodologically interesting measures, such as the magnitude of ecological bias (difference between within-study and across-study associations) and the amount of inconsistency (difference between direct and indirect evidence in a network meta-analysis)

Value Chain Development With The Extremely Poor: Evidence And Lessons From CARE, Save The Children, And World Vision

CARE, Save the Children, and World Vision are combining value chain development (VCD) with gender and nutrition programming to alleviate poverty and food insecurity among the extremely poor. We explore what is unique about VCD with the extremely poor and how specific levers enhance productivity and profitability, equity, and empowerment. We offer evidence to date and lessons learned

Extensible Component Based Architecture for FLASH, A Massively Parallel, Multiphysics Simulation Code

FLASH is a publicly available high performance application code which has evolved into a modular, extensible software system from a collection of unconnected legacy codes. FLASH has been successful because its capabilities have been driven by the needs of scientific applications, without compromising maintainability, performance, and usability. In its newest incarnation, FLASH3 consists of inter-operable modules that can be combined to generate different applications. The FLASH architecture allows arbitrarily many alternative implementations of its components to co-exist and interchange with each other, resulting in greater flexibility. Further, a simple and elegant mechanism exists for customization of code functionality without the need to modify the core implementation of the source. A built-in unit test framework providing verifiability, combined with a rigorous software maintenance process, allow the code to operate simultaneously in the dual mode of production and development. In this paper we describe the FLASH3 architecture, with emphasis on solutions to the more challenging conflicts arising from solver complexity, portable performance requirements, and legacy codes. We also include results from user surveys conducted in 2005 and 2007, which highlight the success of the code.Comment: 33 pages, 7 figures; revised paper submitted to Parallel Computin

Multivariate and network meta-analysis of multiple outcomes and multiple treatments: rationale, concepts, and examples

Organisations such as the National Institute for Health and Care Excellence require the synthesis of evidence from existing studies to inform their decisions—for example, about the best available treatments with respect to multiple efficacy and safety outcomes. However, relevant studies may not provide direct evidence about all the treatments or outcomes of interest. Multivariate and network meta-analysis methods provide a framework to address this, using correlated or indirect evidence from such studies alongside any direct evidence. In this article, the authors describe the key concepts and assumptions of these methods, outline how correlated and indirect evidence arises, and illustrate the contribution of such evidence in real clinical examples involving multiple outcomes and multiple treatment

The Heritage Landscape of Plymouth, MA Greenway Planning and Cultural Design

In anticipation of the 400th anniversary of the Pilgrim’s landing in 1620, this studio combined greenway planning and cultural landscape design and interpretation to revitalize the public landscape of Plymouth, Massachusetts and convey the significance of these historic places to visitors and residents. Through the use of landscape research combining GIS data and analysis with historical narratives and maps, this fourteen-week senior BSLA capstone studio developed a regional and town-scale greenway plan along with detailed designs of individual public landscapes in historic downtown Plymouth

Nantucket Shellfish Management Plan

Nantucket’s shellfisheries are significant both locally and nationally. Locally, commercial and recreational shellfishing are critical to the Island’s history, culture, and economy. Nationally, the Island’s largest commercial shellfishery — the Nantucket bay scallop fishery is one of the last wild-harvest bay scallop fisheries in the country, but there is growing concern over the health of the overall population and the sustainability of the fishery. Given the importance of the shellfisheries on Nantucket and the drastic decline of bay scallop populations elsewhere along the Atlantic coast, there is a compelling interest in ensuring that the Town’s shellfish are managed to sustain both the shellfishing industry and the resources. This is the first official management plan for commercially and recreationally harvested shellfish in Nantucket waters. The Plan addresses bay scallops, quahogs, oysters, mussels, soft‐shell clams, and conchs

Spin and valley control of free carriers in single-layer WS2

Data are available from http://dx.doi.org/10.17630/a25b95c6-b9e8-4ecf-9559-bb09e58a7835The semiconducting single-layer transition metal dichalcogenides have been identified as ideal materials for accessing and manipulating spin- and valley-quantum numbers due to a set of favorable optical selection rules in these materials. Here, we apply time- and angle-resolved photoemission spectroscopy to directly probe optically excited free carriers in the electronic band structure of a high quality single layer (SL) of WS2 grown on Ag(111). We present a momentum resolved analysis of the optically generated free hole density around the valence band maximum of SL WS2 for linearly and circularly polarized optical excitations. We observe that the excited free holes are valley polarized within the upper spin-split branch of the valence band, which implies that the photon energy and polarization of the excitation permit selective excitations of free electron-hole pairs with a given spin and within a single valley.PostprintPeer reviewe