Matrices of Optimal Tree-Depth and Row-Invariant Parameterized Algorithm for Integer Programming

A long line of research on fixed parameter tractability of integer programming culminated with showing that integer programs with n variables and a constraint matrix with tree-depth d and largest entry ? are solvable in time g(d,?) poly(n) for some function g, i.e., fixed parameter tractable when parameterized by tree-depth d and ?. However, the tree-depth of a constraint matrix depends on the positions of its non-zero entries and thus does not reflect its geometric structure. In particular, tree-depth of a constraint matrix is not preserved by row operations, i.e., a given integer program can be equivalent to another with a smaller dual tree-depth. We prove that the branch-depth of the matroid defined by the columns of the constraint matrix is equal to the minimum tree-depth of a row-equivalent matrix. We also design a fixed parameter algorithm parameterized by an integer d and the entry complexity of an input matrix that either outputs a matrix with the smallest dual tree-depth that is row-equivalent to the input matrix or outputs that there is no matrix with dual tree-depth at most d that is row-equivalent to the input matrix. Finally, we use these results to obtain a fixed parameter algorithm for integer programming parameterized by the branch-depth of the input constraint matrix and the entry complexity. The parameterization by branch-depth cannot be replaced by the more permissive notion of branch-width

Highly Active Chiral Ruthenium Catalysts for Asymmetric Ring-Closing Olefin Metathesis

The synthesis of olefin metathesis catalysts containing chiral, monodentate N-heterocyclic carbenes and their application to asymmetric ring-closing metathesis (ARCM) are reported. These catalysts retain the high levels of reactivity found in the related achiral variants (1a and 1b). Using the parent chiral catalysts 2a and 2b and derivatives that contain steric bulk in the meta positions of the N-bound aryl rings (catalysts 3−5), five- through seven-membered rings were formed in up to 92% ee. The addition of sodium iodide to catalysts 2a−4a (to form 2b−4b in situ) caused a dramatic increase in enantioselectivity for many substrates. Catalyst 5a, which gave high enantiomeric excesses for certain substrates without the addition of NaI, could be used in loadings of ≤1 mol %. Mechanistic explanations for the large sodium iodide effect as well as possible mechanistic pathways leading to the observed products are discussed

Experimental Investigation of Premixed Turbulent Combustion in High Reynolds Number Regimes using PLIF

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140710/1/6.2014-0314.pd

Monitoring Waste to Minimize Waste at the University of Massachusetts Amherst

The University of Massachusetts Amherst is committed to sustainability, however, the campus could further reduce its costs and save energy by optimizing the current method of waste removal. The Intergovernmental Panel on Climate Change predicts that by the end of the century, Earth’s average temperature will rise by 11 degrees Fahrenheit unless society takes action to reduce greenhouse gas emissions. According to the EPA, about one-third of carbon emissions in the U.S. come from transportation. Campus garbage bins are collected by carbon-emitting trucks daily, and large truckable waste compactors are collected about three times per week. The amount of harmful carbon emissions released by trucking all of the compactors to their disposal sites totals 9,600 pounds of CO2 (the weight of 12 grand pianos) every week. In this analysis, the current waste removal system is investigated and a method is proposed to save UMass money and energy by reducing the number of waste collections. Initial research focused on how traditional bins could be replaced with solar-powered compactors from Bigbelly Solar Inc. to reduce pickup frequency and generate revenue from separating waste. Findings indicate that solar compactors alone would not have a worthwhile impact on the energy consumption of the UMass campus. Alternatively, a monitoring system that reduces how frequently waste compactors are hauled from campus would have greater impact, saving $1,000 every two weeks, reducing harmful carbon emissions, and using less diesel fuel. Due to the current environmental crisis, UMass should take action to reduce its carbon footprint through this economically favorable system

Hydrogen-atom Attack on Phenol and Toluene is \u3cem\u3eortho\u3c/em\u3e-directed

The reaction of H + phenol and H/D + toluene has been studied in a supersonic expansion after electric discharge. The (1 + 1′) resonance-enhanced multiphoton ionization (REMPI) spectra of the reaction products, at m/z = parent + 1, or parent + 2 amu, were measured by scanning the first (resonance) laser. The resulting spectra are highly structured. Ionization energies were measured by scanning the second (ionization) laser, while the first laser was tuned to a specific transition. Theoretical calculations, benchmarked to the well-studied H + benzene → cyclohexadienyl radical reaction, were performed. The spectrum arising from the reaction of H + phenol is attributed solely to the ortho-hydroxy-cyclohexadienyl radical, which was found in two conformers (syn and anti). Similarly, the reaction of H/D + toluene formed solely the ortho isomer. The preference for the ortho isomer at 100–200 K in the molecular beam is attributed to kinetic, not thermodynamic effects, caused by an entrance channel barrier that is ∼5 kJ mol−1 lower for ortho than for other isomers. Based on these results, we predict that the reaction of H + phenol and H + toluene should still favour the ortho isomer under elevated temperature conditions in the early stages of combustion (200–400 °C)

Biological Implications of Hydroxyapatite Coatings on 3D Printed Titanium Implants

This study sought to determine the growth of and viability of osteoblast cells on hydroxyapatite coatings of 3D-printed titanium implants. The experiment used twenty 3D-printed titanium disks each of which had a determined surface roughness. These disks were printed by Tangible Solutions, LLC (Fairborn, OH) and then sonicated. Ten of the disks were coated with hydroxyapatite through the process of electrodeposition using an open cell and a three lead potentiostat. Using the hydroxyapatite coated titanium disks and uncoated disks, two four-day growth trials were performed. Two trials used five control disks (uncoated titanium disks) and five coated disks each, making an n of 10 for the total experiment. The disks were each placed into the wells of a culture plate and each disk was seeded with 15,000 human osteoblast cells. After four days in the incubator, the cells were removed using trypsin and the counted using the CytoSmart Automated Hemocytometer. The cell count from each disk as well as the viability of the cells from each disk were recorded. Means comparison was performed using Tukey-Kramer method of analysis. Results from the cell count portion of the experiment showed that the mean of the hydroxyapatite group was not significantly greater than the control group (p=0.83). In addition, cell viability of the hydroxyapatite group was also not significantly different than the control group (p=0.31). This data was unexpected but may be due to a change in the surface roughness between the two groups caused by the hydroxyapatite coating decreasing the surface roughness. The surface roughness selected for the experiment was chosen due to it being the most ideal for osteoblast growth, but any less rough surfaces were shown to be less ideal for osteoblast cell growth. Future Experiments will remove the variable of surface roughness

Multiparameter estimation in networked quantum sensors

We introduce a general model for a network of quantum sensors, and we use this model to consider the following question: When can entanglement between the sensors, and/or global measurements, enhance the precision with which the network can measure a set of unknown parameters? We rigorously answer this question by presenting precise theorems proving that for a broad class of problems there is, at most, a very limited intrinsic advantage to using entangled states or global measurements. Moreover, for many estimation problems separable states and local measurements are optimal, and can achieve the ultimate quantum limit on the estimation uncertainty. This immediately implies that there are broad conditions under which simultaneous estimation of multiple parameters cannot outperform individual, independent estimations. Our results apply to any situation in which spatially localized sensors are unitarily encoded with independent parameters, such as when estimating multiple linear or nonlinear optical phase shifts in quantum imaging, or when mapping out the spatial profile of an unknown magnetic field. We conclude by showing that entangling the sensors can enhance the estimation precision when the parameters of interest are global properties of the entire network

Evidence-Based intervention (Ebi) Mapping: a Systematic approach to Understanding the Components and Logic of Ebis

BACKGROUND: Despite the development of numerous evidence-based interventions (EBIs), many go unused in practice. Hesitations to use existing EBIs may be due to a lack of understanding about EBI components and what it would take to adapt it or implement it as designed. to improve the use of EBIs, program planners need to understand their goals, core components, and mechanisms of action. This paper presents EBI Mapping, a systematic approach based on Intervention Mapping, that can be used to understand and clearly describe EBIs, and help planners put them into practice. METHODS: We describe EBI Mapping tasks and provide an example of the process. EBI Mapping uses principles from Intervention Mapping, a systematic framework for planning multilevel health promotion interventions. EBI Mapping applies the Intervention Mapping steps retrospectively to help planners understand an existing EBI (rather than plan a new one). We explain each EBI Mapping task and demonstrate the process using the VERB Summer Scorecard (VSS), a multi-level community-based intervention to improve youth physical activity. RESULTS: EBI Mapping tasks are: 1) document EBI materials and activities, and their audiences, 2) identify the EBI goals, content, and mechanisms of action, 3) identify the theoretical change methods and practical applications of those methods, 4) describe design features and delivery channels, and 5) describe the implementers and their tasks, implementation strategies, and needed resources. By applying the EBI Mapping tasks, we created a logic model for the VSS intervention. The VSS logic model specifies the links between behavior change methods, practical applications, and determinants for both the at-risk population and environmental change agents. The logic model also links the respective determinants to the desired outcomes including the health behavior and environmental conditions to improve the health outcome in the at-risk population. CONCLUSIONS: EBI Mapping helps program planners understand the components and logic of an EBI. This information is important for selecting, adapting, and scaling-up EBIs. Accelerating and improving the use of existing EBIs can reduce the research-to-practice gap and improve population health

Disambiguating Descriptions: Mapping Digital Special Collections Metadata into Linked Open Data Formats

In this poster we describe the Linked Open Data (LOD) for Digital Special Collections project at the University of Illinois at Urbana-Champaign and describe some of the particular challenges that legacy metadata poses for representation in LOD formats. LOD formats are primarily based on the World Wide Web Consortium’s Resource Description Framework standard which demands both that entities be named by opaque universal identifiers whenever possible but also that metadata descriptions for entities be as unambiguous as possible. The challenges for disambiguating those descriptions are illustrated through examples drawn from digital special collections based at four different digital librariesOpe