Comparison of the markov mesh assumption with other statistical assumptions in the classification of binary data

The thesis deals primarily with the study of Markov mesh statistical dependence and the use of this mesh assumption in pattern classification

Spectroscopic examinations of hydro- and glaciovolcanic basaltic tuffs: Modes of alteration and relevance for Mars

Hydro- and glaciovolcanism are processes that have taken place on both Earth and Mars. The amount of materials produced by these processes that are present in the martian surface layer is unknown, but may be substantial. We have used Mars rover analogue analysis techniques to examine altered tuff samples collected from multiple hydrovolcanic features, tuff rings and tuff cones, in the American west and from glaciovolcanic hyaloclastite ridges in Washington state and in Iceland. Analysis methods include VNIR-SWIR reflectance, MWIR thermal emissivity, thin section petrography, XRD, XRF, and Mössbauer spectroscopy. We distinguish three main types of tuff that differ prominently in petrography and VNIR-SWIR reflectance: minimally altered sideromelane tuff, gray to brown colored smectite-bearing tuff, and highly palagonitized tuff. Differences are also observed between the tuffs associated with hydrovolcanic tuff rings and tuff cones and those forming glaciovolcanic hyaloclastite ridges. For the locations sampled, hydrovolcanic palagonite tuffs are more smectite and zeolite rich while the palagonitized hyaloclastites from the sampled sites are largely devoid of zeolites and relatively lacking in smectites as well. The gray to brown colored tuffs are only observed in the hydrovolcanic deposits and appear to represent a distinct alteration pathway, with formation of smectites without associated palagonite formation. This is attributed to lower temperatures and possibly longer time scale alteration. Altered hydro- or glaciovolcanic materials might be recognized on the surface of Mars with rover-based instrumentation based on the results of this study

Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

Background: Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke. Methods: We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515. Findings: Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p<0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (<1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (<1%) deaths in the albiglutide group. Interpretation: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes. Funding: GlaxoSmithKline

Auditing cost-effectiveness analyses of technological changes

A methodology is developed for auditing cost effectiveness analyses of major technological changes. The methodology is applied to the Work in Process Inventory Control System (WIPICS) recently implemented at NARF, North Island. The approach involves using data on NARF operations to estimate cost functions for each major program of the NARF both before and after the change. Cost comparisons using these models do not show a clear cost savings for the WIPICS system. (Author)http://archive.org/details/auditingcosteffe00hartNAN

Turbulence, Cost Escalation and Capital Intensity Bias in Defense Contracting

The recent growth of defense expenditures has once more raised public concern about cost overruns on defense contractors. Economists have pointed out that cost overruns are not necessarily bad per se; instead, attention should be directed to the question as to whether the procurement policies of the Department of Defense (DoD) satisfy the criterion of economic efficiency (see Peck and Sherer (1962)). In connection with this, applications of the principal-agent model to defense contracting show that not only do cost plus fixed fee (CPFF) contracts create moral hazard problems, but that in fact so long as contractors are risk averse and perfect monitoring of their activities is not possible, inefficiencies will arise whatever the form of the contract employed in DoD procurement (see Ross (1973), Harris and Raviv (1979), and Weitzman (1980)). It has been suggested that improvements in efficiency might be achieved if contracts more closely resembling Arrow-Debreu contingent claims were employed (see Cummins (1977)), but this raises problems of manipulation of the probabilities of occurrence of the relevant states of the world. Looking at the problem of cost escalation from a completely different point of view, biases might be introduced into cost comparisons and into decision making with respect to risky projects simply because of the methodology by cost estimators (see Quirk and Terasawa (1983))

Turbulence, Cost Escalation and Capital Intensity Bias in Defense Contracting

The recent growth of defense expenditures has once more raised public concern about cost overruns on defense contractors. Economists have pointed out that cost overruns are not necessarily bad per se; instead, attention should be directed to the question as to whether the procurement policies of the Department of Defense (DoD) satisfy the criterion of economic efficiency (see Peck and Sherer (1962)). In connection with this, applications of the principal-agent model to defense contracting show that not only do cost plus fixed fee (CPFF) contracts create moral hazard problems, but that in fact so long as contractors are risk averse and perfect monitoring of their activities is not possible, inefficiencies will arise whatever the form of the contract employed in DoD procurement (see Ross (1973), Harris and Raviv (1979), and Weitzman (1980)). It has been suggested that improvements in efficiency might be achieved if contracts more closely resembling Arrow-Debreu contingent claims were employed (see Cummins (1977)), but this raises problems of manipulation of the probabilities of occurrence of the relevant states of the world. Looking at the problem of cost escalation from a completely different point of view, biases might be introduced into cost comparisons and into decision making with respect to risky projects simply because of the methodology by cost estimators (see Quirk and Terasawa (1983))

Investment in Knowledge: A Generalization of Learning By Experience

Learning is often perceived as a cost-reducing endogenous by-product of production processes. In many applications this by-product is modeled as a learning curve; that is, a simple function of time or of cumulative production experience. In an earlier paper we presented an alternative explanation where managers decide what resources to devote to knowledge acquisition. In this paper we expand those results to a situation using a more flexible production technology and emphasizing discounted cost. Our model explains resource and output behavior for a firm that is producing specialized units to contractual order. However, the results are quite general and have implications for investment in research, engineering, science and technology, software development, and worker training. We provide examples where the cost-minimizing producer will choose to invest in knowledge creation early in the production program and then have the rate of investment decline over time. Other interesting results are noted by examining the optimal time paths of the control and state variables in a comparative dynamic analysis.learning augmented planning models, dynamic optimization, optimal control theory, knowledge creation

Preoperative staging, prognostic factors, and outcome for extremity rhabdomyosarcoma: A preliminary report from the intergroup rhabdomyosarcoma study IV (1991–1997)

Background: During the fourth Intergroup Rhabdomyosarcoma (RMS) Study IRS IV 1991–1997, a preoperative staging system was evaluated prospectively for the first time. The authors evaluated this staging system and the role of surgery in extremity RMS in contemporary multimodal therapy. Methods: A total of 139 patients (71 girls; median age, 6 years) were entered in IRS IV with extremity-site RMS. Stage was assigned by the IRSG Preoperative Staging System. Postsurgical group was determined by tumor status after initial surgical intervention. Multivariate analysis was performed using all pretreatment factors that were significant by univariate analysis, including clinical Group lie, I through IV), tumor invasiveness (T1,T2), nodal status (N0,N1), and tumor size (< or ≥5 cm). Failure-free survival rates (FFS) and survival rates were estimated using the Kaplan and Meier method. Results: Preoperative staging and clinical group distribution were as follows: Stage 2, n = 34; Stage 3, n = 73; Stage 4, n = 32; Group I, n = 31; Group II, n = 21; Group III, n = 54; Group IV, n = 33. Three-year FFS was 55%, and the overall survival rate was 70%. Eighty-seven patients had either unresectable, gross residual disease (Group III) or metastases (Group IV). FFS was significantly worse for these patients with advanced disease, compared with that for patients with complete resection or with only microscopic residual tumor lie, Group I or II; Group I, 3-year FFS, 91%; Group II, 72%; Group III, 50%; Group IV, 23%; P < .001). Lymph nodes were evaluated surgically in 76 patients with positive results in 38. Clinically, 13 additional patients had nodal disease. Both stage and group were highly predictive of outcome and were highly correlated. By multivariate analysis, none of the other variables were predictors of FFS. Conclusions: This review confirms the utility of pretreatment staging for stratification of patients with extremity RMS with widely different risks of relapse, thereby paving the way for development of risk-based therapy. Group (operative staging) remains the most important predictor of FFS, emphasizing the importance of complete gross resection at initial surgical intervention, when feasible without loss of limb function. The high incidence of nodal disease in the patients who had lymph node biopsy confirms the need for surgical evaluation of lymph nodes to ensure accurate staging in children with extremity rhabdomyosarcoma