Inter-dependence of the volume and stress ensembles and equipartition in statistical mechanics of granular systems

We discuss the statistical mechanics of granular matter and derive several significant results. First, we show that, contrary to common belief, the volume and stress ensembles are inter-dependent, necessitating the use of both. We use the combined ensemble to calculate explicitly expectation values of structural and stress-related quantities for two-dimensional systems. We thence demonstrate that structural properties may depend on the angoricity tensor and that stress-based quantities may depend on the compactivity. This calls into question previous statistical mechanical analyses of static granular systems and related derivations of expectation values. Second, we establish the existence of an intriguing equipartition principle - the total volume is shared equally amongst both structural and stress-related degrees of freedom. Third, we derive an expression for the compactivity that makes it possible to quantify it from macroscopic measurements.Comment: 5 pages, including 2 figures, To appear in Phys. Rev. Let

Developing Standard Production Cost Factors for Major Defense Acquisition Program (MDAP) Platforms

Cost estimators commonly use the analogy and factor method when developing Major Defense Acquisition Program (MDAP) estimates. Previous studies discussing and developing factors for the production lifecycle phase have been limited in scope and statistical analysis efforts. This research significantly expands the currently available toolkit for Department of Defense cost analysts by updating the current database of historical data and exploring potential relationships through statistical testing. Specifically, 3,462 unique factors were created across nine level II Work Breakdown Structure (WBS) elements broken down into four categories; commodity type, contract type, contractor type, and service. The production cost factors were created using data points from 145 MDAPs spanning from 1953 to 2018. Calculated factors were statistically tested for significant differences in their respective WBS element (by category) using non-parametric methods. The updated database and findings will aid analysts in quickly identifying categories that may impact their cost estimate. The practical and statistical analysis performed provide cost estimators with guidance and an improved toolkit for production cost factors

Optimising use of electronic health records to describe the presentation of rheumatoid arthritis in primary care: a strategy for developing code lists

Background Research using electronic health records (EHRs) relies heavily on coded clinical data. Due to variation in coding practices, it can be difficult to aggregate the codes for a condition in order to define cases. This paper describes a methodology to develop ‘indicator markers’ found in patients with early rheumatoid arthritis (RA); these are a broader range of codes which may allow a probabilistic case definition to use in cases where no diagnostic code is yet recorded. Methods We examined EHRs of 5,843 patients in the General Practice Research Database, aged ≥30y, with a first coded diagnosis of RA between 2005 and 2008. Lists of indicator markers for RA were developed initially by panels of clinicians drawing up code-lists and then modified based on scrutiny of available data. The prevalence of indicator markers, and their temporal relationship to RA codes, was examined in patients from 3y before to 14d after recorded RA diagnosis. Findings Indicator markers were common throughout EHRs of RA patients, with 83.5% having 2 or more markers. 34% of patients received a disease-specific prescription before RA was coded; 42% had a referral to rheumatology, and 63% had a test for rheumatoid factor. 65% had at least one joint symptom or sign recorded and in 44% this was at least 6-months before recorded RA diagnosis. Conclusion Indicator markers of RA may be valuable for case definition in cases which do not yet have a diagnostic code. The clinical diagnosis of RA is likely to occur some months before it is coded, shown by markers frequently occurring ≥6 months before recorded diagnosis. It is difficult to differentiate delay in diagnosis from delay in recording. Information concealed in free text may be required for the accurate identification of patients and to assess the quality of care in general practice

Accountability, Strategy, and International Non-Governmental Organizations

Increased prominence and greater influence expose international non-governmental development and environmental organizations (INGOs) to increased demands for accountability from a wide variety of stakeholdersdonors, beneficiaries, staffs, and partners among others. This paper focuses on developing the concept of INGO accountability, first as an abstract concept and then as a strategic idea with very different implications for different INGO strategies. We examine those implications for INGOs that emphasize service delivery, capacity-building, and policy influence. We propose that INGOs committed to service delivery may owe more accountability to donors and service regulators; capacity-building INGOs may be particularly obligated to clients whose capacities are being enhanced; and policy influence INGOs may be especially accountable to political constituencies and to influence targets. INGOs that are expanding their activities to include new initiatives may need to reorganize their accountability systems to implement their strategies effectively. This publication is Hauser Center Working Paper No. 7. The Hauser Center Working Paper Series was launched during the summer of 2000. The Series enables the Hauser Center to share with a broad audience important works-in-progress written by Hauser Center scholars and researchers

Improving Acquisitions In Science And Technology Programs: Creating Unique Cost Factors To Improve Resource Allocation Decisions

Acquisition Research Program Sponsored Report SeriesSponsored Acquisition Research & Technical ReportsCost factors are a common technique employed in Major Defense Acquisition Program (MDAP) cost estimating. The extant suite of available factors, however, primarily consists of development factors from the Engineering and Manufacturing Development (EMD) phase of the life cycle. This study expands the set of factors available to analysts by producing cost factors germane to programs early in the life cycle (i.e. Science and Technology (S&T) programs) and also creates factors for the Production phase of the life cycle. Cost factor development in S&T programs provides unique challenges due to non-standard reporting requirements. To meet these challenges, this study first mapped S&T cost data to create a new, suggested Work Breakdown Structure (WBS) that mirrors the WBS structure utilized in MDAPs via Mil-Std-881. From this, it was determined that two cost factors commonly utilized in MDAP estimates, Systems Engineering/Program Management (SE/PM) and Systems Test and Evaluation (ST&E) could be derived for the S&T programs. The creation of factors for the production phase of the life cycle resulted in 1033 new cost factors from a multitude of diverse programs. Factors were developed by commodity type (aircraft, missile, UAV, space, and ship), contract type (various), contractor type (prime and sub), and Service (Air Force, Army, and Navy). Combining the results of the previous EMD factors developed (Markman et al., 2019) with the two new phases developed here (S&T; Production) results in a robust cost factor toolkit across the acquisition life cycle spectrum.Approved for public release; distribution is unlimited.Approved for public release; distribution is unlimited

An empirical cognitive model of the development of shared understanding of requirements

It is well documented that customers and software development teams need to share and refine understanding of the requirements throughout the software development lifecycle. The development of this shared understand- ing is complex and error-prone however. Techniques and tools to support the development of a shared understanding of requirements (SUR) should be based on a clear conceptualization of the phenomenon, with a basis on relevant theory and analysis of observed practice. This study contributes to this with a detailed conceptualization of SUR development as sequence of group-level state transi- tions based on specializing the Team Mental Model construct. Furthermore it proposes a novel group-level cognitive model as the main result of an analysis of data collected from the observation of an Agile software development team over a period of several months. The initial high-level application of the model shows it has promise for providing new insights into supporting SUR development

Self-reported quality care for knee osteoarthritis: comparisons across Denmark, Norway, Portugal and the UK

Objectives: To assess and compare patient perceived quality of osteoarthritis (OA) management in primary healthcare in Denmark, Norway, Portugal and the UK. Methods: Participants consulting with clinical signs and symptoms of knee OA were identified in 30 general practices and invited to complete a cross-sectional survey including quality indicators (QI) for OA care. A QI was considered as eligible if the participant had checked 'Yes' or 'No', and as achieved if the participant had checked 'Yes' to the indicator. The median percentage (with IQR and range) of eligible QIs achieved by country was determined and compared in negative binominal regression analysis. Achievement of individual QIs by country was determined and compared using logistic regression analyses. Results: A total of 354 participants self-reported QI achievement. The median percentage of eligible QIs achieved (checked 'Yes') was 48% (IQR 28%, 64%; range 0-100%) for the total sample with relatively similar medians across three of four countries. Achievement rates on individual QIs showed a large variation ranging from 11% (referral to services for losing weight) to 67% (information about the importance of exercise) with significant differences in achievement rates between the countries. Conclusions: The results indicated a potential for improvement in OA care in all four countries, but for somewhat different aspects of OA care. By exploring these differences and comparing healthcare services, ideas may be generated on how the quality might be improved across nations. Larger studies are needed to confirm and further explore the findings.EULAR Health Professional Grant; Norwegian Fund through the FYSIOPRIM project; National Institute for Health Research (NIHR) [RP-PG-0407-10 386]; Arthritis Research UK Centre in Primary Care grant [18139]; National Institute for Health Research (NIHR) Collaborations for Leadership in Applied Health Research and Care West Midlands by a Knowledge Mobilisation Research Fellowship from the National Institute for Health Research; National Institute for Health Research (NIHR); Fundacao para a Ciencia e Tecnologia [PEst-OE/MAT/UI0006/2014]info:eu-repo/semantics/publishedVersio

Cost-effectiveness of a model consultation to support self-management in patients with osteoarthritis

Objectives: The aim of this study was to estimate the cost-effectiveness of a model OA consultation for OA to support self-management compared with usual care. Methods: An incremental cost-utility analysis using patient responses to the three-level EuroQoL-5D (EQ-5D) questionnaire was undertaken from a UK National Health Service perspective alongside a two-arm cluster-randomized controlled trial. Uncertainty was explored through the use of cost-effectiveness acceptability curves. Results: Differences in health outcomes between the model OA consultation and usual care arms were not statistically significant. On average, visits to the orthopaedic surgeon were lower in the model OA consultation arm by -0.28 (95% CI: -0.55, -0.06). The cost-utility analysis indicated that the model OA consultation was associated with a non-significant incremental cost of £-13.11 (95% CI: -81.09 to 54.85) and an incremental quality adjusted life year (QALY) of -0.003 (95% CI: -0.03 to 0.02), with a 44% chance of being cost-effective at a threshold of £20 000 per QALY gained. The percentage of participants who took time off and the associated productivity cost were lower in the model OA consultation arm. Conclusion: Implementing National Institute for Health and Care Excellence guidelines using a model OA consultation in primary care does not appear to lead to increased costs, but health outcomes remain very similar to usual care. Even though the intervention seems to reduce the demand for orthopaedic surgery, overall it is unlikely to be cost-effective

Motive-demand dynamics creating a social context for students’ learning experiences in a making and design environment

Making and design environments, often referred to as makerspaces, have aroused recent educational interest. These environments typically consist of spaces that support interest-driven engagement in hands-on creative activities with a range of digital artefacts. Although a variety of benefits from participating in making and design activities have been proposed, we currently have limited understanding of students’ learning experiences in makerspaces situated in schools. Following Hedegaards’ conceptualisations, we investigate motive-demand dynamics in students’ social activity in a school-based digital making and design environment, ‘The FUSE Studio’. We highlight our findings via vignettes selected from 65 h of video recordings of 94 students (aged between 9 and 12 years old) carrying out activities; the recordings were collected intermittently from an elective course over one semester. Our study illustrates how the students’ learning experiences were shaped through tension-laden interplay between the motives and demands of their activity situated across personal, relational and institutional contexts. The findings make visible how established ways of working and being at school interacted and came into tension with the students’ motive orientations, thereby limiting and at times transforming the social context of their learning. Our work also demonstrates how the analysis of motive-demand dynamics offers one useful conceptual tool to unpack students’ learning experiences in novel learning environments.Peer reviewe