1,284 research outputs found
War Plan Orange: Powerful Stuff
Though Churchill called the battle of the Atlantic the dominating factor all through the war, the dramatic struggle in the Pacific became the focus of attention for many of the war correspondents and of naval historians of World War II. War Plan Orange (Orange meant Japan), was the name given by the U.S. Navy to its long planning efforts for a war at sea against Japan . As the plan evolved from 1907 through 1941, it became the front-stage-center upon which the Battle of the Pacific was played. As Edward S. Miller observes, the Navy painted Orange Plans on canvases of heroic size. Planning the path to victory in the Pacific was interrupted-but not ended-by the Japanese surprise attack on Pearl Harbor
An Analysis of the Falkland/Malvinas Islands Campaign
The profession of arms is not only a life of dedication, sacrifice, and frustration, it is a life of intellectual challenge. For you see, when we are called upon for combat, it means we have failed as a nation. When guns speak and blood flows, we have failed in our pursuit of the first and foremost political objective assigned the armed forces: that of deterring war. We should all be acutely aware that the Armed Forces of the United States has no life in and of itself. It exists for one purpose and one purpose only: to support the political objectives of this Nation. What that service shall consist of is determined by the people and by their elected representatives. How that service shall be performed, on the other hand, is the central element of the military profession. How we perform in our stewardship is the measure of our worth to the Nation
Closed-Form Bayesian Inferences for the Logit Model via Polynomial Expansions
Articles in Marketing and choice literatures have demonstrated the need for
incorporating person-level heterogeneity into behavioral models (e.g., logit
models for multiple binary outcomes as studied here). However, the logit
likelihood extended with a population distribution of heterogeneity doesn't
yield closed-form inferences, and therefore numerical integration techniques
are relied upon (e.g., MCMC methods).
We present here an alternative, closed-form Bayesian inferences for the logit
model, which we obtain by approximating the logit likelihood via a polynomial
expansion, and then positing a distribution of heterogeneity from a flexible
family that is now conjugate and integrable. For problems where the response
coefficients are independent, choosing the Gamma distribution leads to rapidly
convergent closed-form expansions; if there are correlations among the
coefficients one can still obtain rapidly convergent closed-form expansions by
positing a distribution of heterogeneity from a Multivariate Gamma
distribution. The solution then comes from the moment generating function of
the Multivariate Gamma distribution or in general from the multivariate
heterogeneity distribution assumed.
Closed-form Bayesian inferences, derivatives (useful for elasticity
calculations), population distribution parameter estimates (useful for
summarization) and starting values (useful for complicated algorithms) are
hence directly available. Two simulation studies demonstrate the efficacy of
our approach.Comment: 30 pages, 2 figures, corrected some typos. Appears in Quantitative
Marketing and Economics vol 4 (2006), no. 2, 173--20
962-61 Late Redistribution T1-201/Stress Tc-99m Sestamibi Separate Acquisition Dual Isotope Myocardial Perfusion SPECT: A Feasibility Study
Rest TI201(TI)/stress Tc-sestamibi dual isotope SPECT (DIMPS) is an efficient myocardial perfusion protocol. Patients with rest defects, however, frequently require late TI redistribution imaging the next day. Thus, we recently implemented a modified DIMPS (M-DIMPS), with 3.5 mCi TI injected at rest the night before stress testing. On the day of stress testing, 12–18 hr redistribution TI (late TI) SPECT was performed prior to stress sestamibi study. To assess image quality of late TI, we prospectively studied 107 patients who underwent M-DIMPS. For purposes of comparison between conventional DIMPS and M-DIMPS, a subset (group A, n=41) also had rest TI(25sec/stop, 60 stops) the night before M-DIMPS. Late TI used 30sec/stop. Prereconstruction processing used a 20 Butterworth filter (cut-off: 0.5/order 10 for rest TI, 0.35/order 10 for late TI). Comparisons were made for cardiac counts (counts/pixel) and quantitative heart to background ratio (H/B ratio). Image quality was assessed visually using a 5 point score (0=unacceptable, 4=excellent), based on the evaluation of image uniformity, defect clarity, left ventricular border definition and the apparent H/B ratio, Comparisons between rest TI and late TI in 41 group A patients yielded quantitative H/B ratio of 1.63±0.39 and 1.49±0,31 (p=0.002), and total myocardial counts of 41.4±18.1 and 29.3±11.6 (p<0.001), respectively. Image quality agreement between rest TI and late TI was 90%, with 31 concordant good to excellent and 6 concordant fair studies. Analysis of the 107 late TI studies by patient weight revealed:<150 Ibs (n = 31)150–200 Ibs (n = 60)>200 Ibs (n = 16)pcardiac counts30.4±9.628.9±13.828.9±7.5nsH/B ratio1.49±0.241.46±0.321.42±0.25nsquality = 3 or 490%90%63%<0.05**> 200lbs vs. the other two weight categoriesConclusionAlthough quantitatively different, late TI has acceptable count statistics and comparable visual image quality to rest TI, establishing the feasibility of late TI/stress Tc-sestamibi dual isotope SPECT in non-obese (<200 Ibs) patients. The protocol allows for final reporting on the same day as stress testing, potentially decreasing the length of hospitalization
Practical solutions for sampling alternatives in large-scale models
Many large-scale real-world transport applications have choice sets that are so large as to make model estimation and application computationally impractical. The ability to estimate models on subsets of the alternatives is thus of great appeal, and correction approaches have existed since the late 1970s for the simple multinomial logit (MNL) model. However, many of these models in practice rely on nested logit specifications, for example, in the context of the joint choice of mode and destination. Recent research has put forward solutions for such generalized extreme value (GEV) structures, but these structures remain difficult to apply in practice. This paper puts forward a simplification of the GEV method for use in computationally efficient implementations of nested logit. The good performance of this approach is illustrated with simulated data, and additional insights into sampling error are also provided with different sampling strategies for MNL
Recommended from our members
Commonwealth of Massachusetts Mill Building Repurposing Pilot Project (Twist Mill - Athol, MA)
The purpose of the UMass Amherst Department of Landscape Architecture and Regional Planning’s participation in this project is to establish a redevelopment action plan that incorporates the ownership’s clear vision for reuse of the site, proposes solutions to various obstacles that have hindered progress, and serves as a guiding model in terms of improving the feasibility of similar projects throughout the state.
The project team gathered information from a variety of resources, and conducted three distinct phases of analysis in order to complete this redevelopment action plan. The Phase I: Inventory examines the physical, regulatory, and financial context surrounding the current site in order to gauge its condition as a viable location to foster desired economic development for the region.
The Phase II: Assessment utilizes these inventory findings to identify clear challenges that impact the redevelopment potential of the site in an effort to reduce overall project roadblocks. The Phase III: Implementation provides strategies to alleviate these challenges moving forward, in the form of clear recommendations for local, regional, and state level regulatory improvements.
Phases I and II were conducted in the fall of 2013, and Phase III was conducted in the spring of 2014.
Particular thanks for guidance on this project are extended to L.P. Athol Corporation ownership, Dr. John Mullin of the UMass Amherst Center for Economic Development, State Representative Denise Andrews of the Franklin County Second District, State Senator Stephen Brewer, State Senator Stanley Rosenberg, Congressman James McGovern, and the Town of Athol
General Chemistry Student Attitudes and Success with Use of Online Homework: Traditional- Responsive versus Adaptive-Responsive
We investigated whether use of an adaptive-responsive online homework system (OHS) that tailors homework to students’ prior knowledge and periodically reassesses students to promote learning through practice retrieval has inherent advantages over traditional-responsive online homework. A quasi-experimental cohort control post-test-only design with nonequivalent groups and propensity scores with nearest neighbor matching (n = 6,114 pairs) was used. The adaptive system was found to increase the odds of a higher final letter grade for average, below average, and failing students. However, despite the learning advantages, students self-reported less favorable attitudes toward adaptive-responsive (3.15 of 5) relative to traditional-responsive OHS (3.31). Specific to the adaptive OHS, the following were found: (i) student attitudes were moderately and positively correlated (r = 0.36, p \u3c 0.01) to final letter grade, (ii) most students (95%) reported engaging in remediation of incorrect responses, (iii) a majority of students (69%) reported changes in study habits, and (iv) students recognized the benefit of using adaptive OHS by ranking its assignments and explanations or review materials as two of the top three most useful course aspects contributing to perceived learning. Instructors can use our findings to inform their choice of online homework system for formative assessment of chemistry learning by weighing the benefits, disadvantages, and learning pedagogies of traditional-responsive versus adaptive-responsive systems
OMA orthology in 2021: website overhaul, conserved isoforms, ancestral gene order and more.
OMA is an established resource to elucidate evolutionary relationships among genes from currently 2326 genomes covering all domains of life. OMA provides pairwise and groupwise orthologs, functional annotations, local and global gene order conservation (synteny) information, among many other functions. This update paper describes the reorganisation of the database into gene-, group- and genome-centric pages. Other new and improved features are detailed, such as reporting of the evolutionarily best conserved isoforms of alternatively spliced genes, the inferred local order of ancestral genes, phylogenetic profiling, better cross-references, fast genome mapping, semantic data sharing via RDF, as well as a special coronavirus OMA with 119 viruses from the Nidovirales order, including SARS-CoV-2, the agent of the COVID-19 pandemic. We conclude with improvements to the documentation of the resource through primers, tutorials and short videos. OMA is accessible at https://omabrowser.org
Photophysics of cage/guest assemblies : photoinduced electron transfer between a coordination cage containing osmium(II) luminophores, and electron-deficient bound guests in the central cavity
An octanuclear cubic Os4Zn4 coordination cage, containing Os(II) tris-diimine units at four of the eight vertices which are good photoelectron donors from their 3MLCT excited state, performs photoinduced electron transfer to electron-accepting organic guests which bind in the central cavity in water via the hydrophobic effect: the resulting charge-separated states have lifetimes of ca. 200 ps and have been characterized by transient absorption spectroscopy
- …