Needle-Moving Community Collaboratives: A Promising Approach to Addressing America's Biggest Challenges

Communities face powerful challenges -- a high-school dropout epidemic, youth unemployment, teen pregnancy -- that require powerful solutions. In a climate of increasingly constrained resources, those solutions must help communities to achieve more with less. A new kind of community collaborative -- an approach that aspires to significant community-wide progress by enlisting all sectors to work together toward a common goal -- offers enormous promise to bring about broader, more lasting change across the nation

B2C eCommerce Strategy and Market Structure: The Survey Based Approach

This paper follows two objectives: (i) It demonstrates the merits of the survey based approach to B2C eCommerce characteristics and company strategy, and (ii) it presents empirical evidence of the crucial importance of size and marketing investment in B2C eCommerce markets. It presents econometric estimates of the effects of company characteristics and company strategies on the performance of Viennese B2C eCommerce companies in 2001. We provide econometric analysis of three dependent variables in turn: (i) number of B2C eCommerce customers in 2000, (ii) number of B2C eCommerce employees in January 2001 and (iii) revenue growth rate in 2001. The models do explain the data quite well: Size as well as endogenous sunk costs emerge as the main success factors. Furthermore, the results of nonparametric tests are presented. They mostly confirm the econometric evidence. We also show that the quantitative results are consistent with the qualitative results of the surveys. Finally, we argue that the survey based approach to B2C eCommerce is a method that provides reliable and consistent data, and that it complements the approach based on prices and consumer behavior commonly applied.B2C eCommerce, empirical evidence, success factors, endogenous sunk costs, market structure

Space reactor/Stirling cycle systems for high power lunar application

An analysis is performed to mathematically model a 550 kWe lunar base power supply which uses a SP-100 reactor coupled with Stirling converters. The reactor is placed in an excavation to keep activated coolant in the hole and to allow maintenance of the components outside the hole. Two technology levels are considered. They are 1050 and 1300 K heater head Stirling converts. It is found that for a 1050 K converter the total mass which provided 1000 volts DC at 250 m is 14,366 kg while the 1300 K system mass is 12,104 kg. The radiation area of the 1050 and 1300 K systems are 641 and 356 sq m respectively. Comparisons are made with Brayton and thermionic systems with both near term and advanced technology considered

B2C eCommerce Strategy and Market Structure: The Survey Based Approach

This paper follows two objectives: (i) It demonstrates the merits of the survey based approach to B2C eCommerce characteristics and company strategy, and (ii) it presents empirical evidence of the crucial importance of size and marketing investment in B2C eCommerce markets. It presents econometric estimates of the effects of company characteristics and company strategies on the performance of Viennese B2C eCommerce companies in 2001. We provide econometric analysis of three dependent variables in turn: (i) number of B2C eCommerce customers in 2000, (ii) number of B2C eCommerce employees in January 2001 and (iii) revenue growth rate in 2001. The models do explain the data quite well: Size as well as endogenous sunk costs emerge as the main success factors. Furthermore, the results of nonparametric tests are presented. They mostly confirm the econometric evidence. We also show that the quantitative results are consistent with the qualitative results of the surveys. Finally, we argue that the survey based approach to B2C eCommerce is a method that provides reliable and consistent data, and that it complements the approach based on prices and consumer behavior commonly applied.B2C eCommerce, empirical evidence, success factors, endogenous sunk costs

Collective Impact in Emergency Response: A Case Study of Milwaukees COVID-19 Civic Response Team

Milwaukee's COVID-19 response has been a remarkable mobilization of resources and organizations to address needs for shelter, food, testing, Internet connection, and more. Necessity has forced such collective efforts in many cities, but Milwaukee's may be unique in the civic architecture that has been built and that may be sustained beyond the crisis.The experience in Milwaukee provides a window into a city's comprehensive response to the COVID-19 crisis that also offers six lessons for how collective impact initiatives can be most effective in both meeting emergency needs and pursuing systems changes

Public-Private Partnerships in Emergency Response: A Case Study of Milwaukees Civic Response Team

The COVID-19 pandemic was an all-hands-on-deck moment. As communities were jolted into emergency response on many fronts—health, jobs, housing, education, childcare, food, and mental health—collaboration and coordination became essential. In Milwaukee, the Civic Response Team united local governments, philanthropy, and nonprofits to collectively manage response and recovery. In just weeks, they housed hundreds of people, delivered tens of thousands of meals, built and promoted a COVID-19 testing system, distributed hundreds of thousands of masks, provided families with technology to connect to school, rescued childcare providers, and soothed anxieties and grief.This paper studies how the public-private partnerships within the Civic Response Team worked during their first year, and shows what we can learn from them to support better partnership and emergency response in the future

Logistic regression in medical decision making and epidemiology

In his recent textbook "Primer of Biostatistics", S, A, Glantz refers to the nowadays growing pressure on clinicians for more effective use of medical resources. He asserts that clinicians should be able to make better informed judgements about claims of medical efficacy. They can participate then more intelligently in the debate on how to allocate medical resources. These better informed judgements are the objective of "medical decision making", where the choices to be made in diagnostic and therapeutic strategies are studied Medical decision making is to be based for a great part on statistical reasoning. A statistical approach which has proven to be valuable in this field is a technique known as logistic regression analysis. The assessment of the performance of this logistic model is the subject of this thesis. Applications in medical decision making are considered, mainly with respect to medical diagnosis. Logistic regression analysis may be viewed as a sophisticated diagnostic aid. Multiple test outcomes and patient characteristics are incorporated into a logistic model for the probability that a patient belongs to a certain disease class. Performance of the logistic model in etiologic-epidemiological studies is another area of study. In this context logistic regression is used for the detection of risk factors, ad jus ted for confounding in order to obtain unbiased assessments. This thesis includes ten chapters, consisting of papers which have either been published or which were recently submitted for publication by the author, many of them in cooperation with various colleagues. The chapters have been grouped into three parts. Part 1 (chapter 1) presents a review of developments in logistic regression from 1970 up to 1986. It outlines statistical aspects of the model such as estimation. hypothesis testing and model selection. Part 2 (chapters 2 - 7) deals with logistic discriminant analysis in medical diagnosis. An extensive evaluation of a logistic model for the diagnosis of Crohn's disease by agglutination reactions is presented in chapter 2. Actually, this chapter results from our evolving insights since the first application of logistic discriminant analysis for the diagnosis of Crohn's disease (chapter 3). Comparison of logistic discrimination with some other discriminant analysis methods is studied in chapter 4 through application to real data from clinical practice, and in chapters 5 and 6 through the use of simulated data. This comparative evaluation was performed on datasets consisting of mixtures of continuous and discrete data. The underlying distribution in the first simulation study (chapter 5) is a fourdimensional normal from which discrete variables were obtained by discretizing the continuous variables. The simulation study in chapter 6 is based on a location model. Within each outcome combination of the discrete variables a multivariate normal distribution is assumed. The next chapter concerns the evaluation oflogistic discriminant analysis for modelling QSAR's, quantitative structure- activity relationships (chapter 7). It is used there as a technique for detecting which chemical compounds will be useful for the development of new drugs. The third and final part of this thesis (chapters 8- 10) is concerned with the application and evaluation of the logistic model in etiologic-epidemiological studies, particularly in case-control studies. In chapter 8 the first epidemiologic application of the logistic model in TheN etherlands, which uses estimates of the model parameters based on conditional likelihood, is presented. Risk factors for stroke are investigated in a case-control study conducted some years ago in Tilburg. In chapter 9 the (multiplicative) logistic model is compared with an (additive) linear model for case-control studies with one continuous exposure factor and without consideration of confounding variables. Some aspects concerning variables selection in epidemiologic studies, also relevant for logistic regression, are discussed in chapter 10. The thesis is concluded with a summary. 1

Preliminary design of a mobile lunar power supply

A preliminary design for a Stirling isotope power system for use as a mobile lunar power supply is presented. Performance and mass of the components required for the system are estimated. These estimates are based on power requirements and the operating environment. Optimizations routines are used to determine minimum mass operational points. Shielding for the isotope system are given as a function of the allowed dose, distance from the source, and the time spent near the source. The technologies used in the power conversion and radiator systems are taken from ongoing research in the Civil Space Technology Initiative (CSTI) program

A solar power system for an early Mars expedition

As NASA looks at missions that will expand human presence in the solar system, the power requirements for such missions need to be defined, developed and analyzed. One mission under consideration consists of a 40 day manned Mars surface expedition to perform science experiments. The mission time was centered around an aerocentric longitude (Ls) of 90 deg to lessen the probability of an occurrence of a local or planetary dust storm. The mission site was arbitrarily located at the Martian equator. The power requirements were assumed to be 40 kWe for life support and experiment power during the Martian day and 20 kWe for life support during the Martian night. A solar energy system consisting of roll-out amorphous silicon arrays and a hydrogen-oxygen regenerative fuel cell energy storage system was chosen for the study. The power available from a roll-out array, when plotted against time, approaches a cosine-like curve and depends on both array area and the amount of solar irradiance impinging on its horizontal surface. The array is sized to provide at least 20 KWe when the sun is 12.5 deg above the horizon and ramp up to 140 kWe peak power at Martian noon. In this configuration, the array is capable of supplying 40 KWe continuously to the user for the majority of the Martian day while supplying the excess energy to the electrolyzer portion of the energy storage system. A roll-out, pumped loop radiator system is used to dissipate the waste heat produced by the fuel cell. The power management and distribution system inverts the power from the individual solar array sub-modules and the fuel cell stacks and connects them to a 440 VAC single phase 20 kHz main bus. The total power system is comprised of 80 individual solar array modules with an integral bus and three energy storage modules consisting of fuel cell and electrolyzer stacks, reactant storage tanks, and a roll-out radiator. Power system mass, stowed volume, and deployed area were determined. Day/night power splits of 40/10 kWe, 40/30 kWe, and 40/40 kWe were also considered to determine the impact of a range of nighttime power requirements on the baseline system

Parametric System Model for a Stirling Radioisotope Generator

A Parametric System Model (PSM) was created in order to explore conceptual designs, the impact of component changes and power level on the performance of the Stirling Radioisotope Generator (SRG). Using the General Purpose Heat Source (GPHS approximately 250 Wth) modules as the thermal building block from which a SRG is conceptualized, trade studies are performed to understand the importance of individual component scaling on isotope usage. Mathematical relationships based on heat and power throughput, temperature, mass, and volume were developed for each of the required subsystems. The PSM uses these relationships to perform component- and system-level trades