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2013

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Articles 8521 - 8550 of 11462

Full-Text Articles in Physical Sciences and Mathematics

Walkcompass: Finding Walking Direction Leveraging Smartphone's Inertial Sensors, Nirupam Roy Jan 2013

Walkcompass: Finding Walking Direction Leveraging Smartphone's Inertial Sensors, Nirupam Roy

Theses and Dissertations

Determining moving direction with smartphone's inertial sensors is a well known problem in the field of location service. Compass alone cannot solve this problem because smartphone's compass cannot achieve high accuracy. Moreover GPS is not suitable in indoor scenario. Another well known approach is dead-reckoning but dead-reckoning needs to know phones initial orientation and over time it keeps accumulating errors and after some time the estimation becomes to noisy to use. To overcome these limitations, we propose a solution called WalkCompass which is specially designed for pedestrians keeping in mind the variation of force during normal human walk. Therefore the …


The Role Of Host-Tumor Interactions In Liver Metastasis Of Colorectal Cancer, Yu Zhang Jan 2013

The Role Of Host-Tumor Interactions In Liver Metastasis Of Colorectal Cancer, Yu Zhang

Theses and Dissertations

Colon cancer is the third most frequent cancer and the second leading cause of cancer deaths in the United States. Liver metastasis is the major cause of death in colon cancer. Successful metastases depend on productive collaborations between tumor cells and host-derived cells in the tumor microenvironment, target organ environments, and cells in the hematopoietic compartment.

To identify the host-tumor interactions promoting liver metastasis and their molecular and cellular mediators, an orthotopic mouse model of liver metastasis of colon cancer was established that recapitulates all stages of tumor growth and metastasis. A highly metastatic mouse carcinoma cell line CT26-FL3 was …


New Ruthenium And Osmium Carbonyl Cluster Complexes With Main Group Bridging Ligands Having Unusual Structures And Bonding, Yuwei Kan Jan 2013

New Ruthenium And Osmium Carbonyl Cluster Complexes With Main Group Bridging Ligands Having Unusual Structures And Bonding, Yuwei Kan

Theses and Dissertations

The reaction of IrRu3(CO)13(µ-H), 2.1 with HSnPh3 in hexane solvent at reflux has provided the new mixed metal cluster compounds Ir2Ru2(CO)11(SnPh3)(µ-H)3, 2.2 and IrRu3(CO)11(SnPh3)3(µ-H)¬4, 2.3 containing SnPh3 ligands. Compound 2.2 which was obtained in low yield (3%) contains a closed cluster having two iridium and two ruthenium atoms, one SnPh3 ligand and three bridging hydride ligands. Compound 2.3 has a butterfly structure for the four metal atoms with three SnPh3 ligands and four bridging hydride ligands around the periphery of the cluster. When compound 2.3 was heated to 97 oC for 30min, IrRu3(CO)9(μ-η2-C6H5)(μ4-SnPh)2(μ-SnPh2), 2.4 was formed by cleavage of phenyl …


Polybenzimidazole Membranes With Enhanced Mechanical Properties For Extended Lifetime Electrochemical Applications, Max Molleo Jan 2013

Polybenzimidazole Membranes With Enhanced Mechanical Properties For Extended Lifetime Electrochemical Applications, Max Molleo

Theses and Dissertations

After approximately 20 years of development, polybenzimidazole (PBI) chemistries and the concomitant manufacturing processes have evolved into commercially produced membrane electrode assemblies (MEAs). Commerical PBI MEAs can operate reliably for over two years at elevated temperatures of 120-180°C due to the physical and chemical robustness of PBI membranes. Recently, the Department of Energy has issued a target of 40,000-80,000 hours for stationary (i.e. combined heat and power, back-up power) polymer electrolyte membrane / proton exchange membrane (PEM) fuel cells. It is known through observation that over time, PBI membranes at 180°C creep in a direction perpendicular to compressive forces, thus …


Investigations Of The Non-Covalent Ch-Π Interactions Using Molecular Torsional Balances, Chen Zhao Jan 2013

Investigations Of The Non-Covalent Ch-Π Interactions Using Molecular Torsional Balances, Chen Zhao

Theses and Dissertations

Several bicycle N-arylimide based molecular balances were designed to study aliphatic CH-pi interactions and aromatic CH-pi interactions (edge-to-face arene-arene interactions). In each case, the geometries of the interactions were characterized in the solid-state via X-ray analysis, and the strengths of interactions were characterized in solution by their folded/unfolded ratios, as measured by integration of their 1H NMR spectra.

The balances are very sensitive to variations in the strengths of weak non-covalent interactions. Several different aspects of the CH-pi interactions were studied, such as sterics, conformational entropy, cooperativity, deuterium isotope effect, substitution effects, and solvent effects. It showed that due to …


Amplitude Vs. Offset Effects On Gas Hydrates At Woolsey Mound, Gulf Of Mexico, Walter R. Anderson Jan 2013

Amplitude Vs. Offset Effects On Gas Hydrates At Woolsey Mound, Gulf Of Mexico, Walter R. Anderson

Theses and Dissertations

Due to the estimated massive quantities of natural methane hydrates, they represent one of the largest sources of future alternative energy on Earth. Methane hydrates have been found in the shallow sub-seafloor of the Northern Gulf of Mexico where the water depth is in excess of ~900 m. Mississippi Canyon Block 118 has been chosen by the Gulf of Mexico Hydrates Research Consortium to be the site of a multi-sensor, multi-discipline sea-floor observatory for gas hydrate research. First evidence for gas hydrates at MC 118 was observed at Woolsey Mound. Subsurface evidence for gas hydrates has subsequently been substantiated by …


An Effective Field Theory Calculation Of N(P, D)Γ Cross-Section For Big Bang Nucleo-Synthesis, Rasha Adnan Kamand Jan 2013

An Effective Field Theory Calculation Of N(P, D)Γ Cross-Section For Big Bang Nucleo-Synthesis, Rasha Adnan Kamand

Theses and Dissertations

Studying the nuclear reaction n(p,d)γ and calculating its cross-section is not only a matter of interest from theoretical particle physics point of view but also from the viewpoint of cosmology. We now know that the universe is made up of only 5% baryonic matter. So, computing the density of baryons is of particular importance to physicists in general and cosmologists in particular. Deuterium production during Big Bang Nucleo-synthesis (BBN) is very sensitive to the density of baryons, thus baryon density can be inferred from the abundance of deuterium. In order to calculate deuterium abundance one needs to use the cross-section …


Quantifying The Impact Of Various Radioactive Background Sources On Germanium-76 Zero-Neutrino-Double-Beta-Decay Experiments, Katarina Leila Mizouni Jan 2013

Quantifying The Impact Of Various Radioactive Background Sources On Germanium-76 Zero-Neutrino-Double-Beta-Decay Experiments, Katarina Leila Mizouni

Theses and Dissertations

The goal of searching for 0vBB-decay is to probe an absolute neutrino mass scale suggested by the mass-splitting parameters observed by neutrino oscillation experiments. Furthermore, observation of 0vBB-decay is an explicit instance of lepton-number non-conservation. To detect the rare events such as 0vBB-decay, half-lives of the order of 10^25-10^27 years have to be probed. Using an active detector with a large volume, such as hundreds of kilograms of HPGe in the case of MAJORANA, and taking efficient measures to mitigate background of cosmic and primordial origins are necessary for the success of a sensitive 0vBB-decay experiment.

One focus of the …


Sharp Bounds Associated With An Irreducibility Theorem For Polynomials Having Non-Negative Coefficients, Morgan Cole Jan 2013

Sharp Bounds Associated With An Irreducibility Theorem For Polynomials Having Non-Negative Coefficients, Morgan Cole

Theses and Dissertations

Consider a polynomial f(x) having non-negative integer coefficients with f(b) prime for some integer b greater than or equal to 2. We will investigate the size of the coefficients of the polynomial and establish a largest such bound on the coefficients that would imply that f(x) is irreducible. A result of Filaseta and Gross has established sharp bounds on the coefficients of such a polynomial in the case that b = 10. We will expand these results for b in {8, 9, ..., 20}.


Applications Of The Lopsided Lovász Local Lemma Regarding Hypergraphs, Austin Tyler Mohr Jan 2013

Applications Of The Lopsided Lovász Local Lemma Regarding Hypergraphs, Austin Tyler Mohr

Theses and Dissertations

The Lovász local lemma is a powerful and well-studied probabilistic technique useful in establishing the possibility of simultaneously avoiding every event in some collection. A principle limitation of the lemma's application is that it requires most events to be independent of one another. The lopsided local lemma relaxes the requirement of independence to negative dependence, which is more general but also more difficult to identify. We will examine general classes of negative dependent events involving maximal matchings of uniform hypergraphs, partitions of sets, and spanning trees of complete graphs. The results on hypergraph matchings (together with the configuration model of …


Decision-Support Tool For Residential Pesticides In The South Carolina Coastal Zone, Lisa Claire Wickliffe Jan 2013

Decision-Support Tool For Residential Pesticides In The South Carolina Coastal Zone, Lisa Claire Wickliffe

Theses and Dissertations

The Environmental Protection Agency (EPA) is charged with ensuring pesticides do not pose unreasonable adverse risks to the public and to the environment. This is a daunting task with over one billion pounds of pesticides used across the nation each year. The U.S. EPA estimates approximately 75% of all pesticide usage in the U.S. are agricultural while 25% is for home, garden, industrial, commercial, and government applications. One area of application of concern to public health and the environment regarding misuse of pesticides is in residential settings. In these instances, individuals may not have any knowledge of identifying whether they …


Scanner: An Efficient And Accurate Trimming Tool For Illumina Next Generation Sequencing Reads, Xiang Zhou Jan 2013

Scanner: An Efficient And Accurate Trimming Tool For Illumina Next Generation Sequencing Reads, Xiang Zhou

All Computer Science and Engineering Research

Recent advances in High-Throughput Sequencing (HTS) technology have greatly facilitated the researches in bioinformatics field. With the ultra-high sequencing speed and improved base-calling accuracy, Illumina Genome Analyzer is currently the most widely used platform in the field. To use the raw reads generated from the sequencing machine, the 3’ adapter sequence attached to the real read in the process of ligation needs to be correctly trimmed. This is often done by some inhouse scripts or different packages with various parameters. They either use the Smith-Waterman algorithm or search for an exact match of the 3’ adapter sequence. In this report, …


Simple Analytic Performance Models For Streaming Data Applications Deployed On Diverse Architectures, Jonathan C. Beard, Roger D. Chamberlain, Mark A. Franklin Jan 2013

Simple Analytic Performance Models For Streaming Data Applications Deployed On Diverse Architectures, Jonathan C. Beard, Roger D. Chamberlain, Mark A. Franklin

All Computer Science and Engineering Research

Modern hardware is inherently heterogeneous. With heterogeneity comes multiple abstraction layers that hide underlying complex systems. While hidden, this complexity makes quantitative performance modeling a difficult task. Designers of high-performance streaming applications for heterogeneous systems must contend with unpredictable and often non-generalizable models to predict performance of a particular application and hardware mapping. This paper outlines a computationally simple approach that can be used to model the overall throughput and buffering needs of a streaming application on heterogeneous hardware. The model presented is based upon a hybrid maximum flow and decomposed discrete queueing model. The utility of the model is …


Automated Color Calibration Of Display Devices, Andrew Shulman Jan 2013

Automated Color Calibration Of Display Devices, Andrew Shulman

All Computer Science and Engineering Research

If you compare two identical images on two different monitors, they will likely appear different. Every display device is supposed to adhere to a particular set of standards regulating the color and intensity of the image it outputs. However, in practice, very few do. Color calibration is the practice of modifying the signal path such that the colors produced more closely match reference standards. This is essential for graphics professionals who are mastering original content. They must ensure that the source material appears correct when viewed on a reference monitor. When viewed on a consumer panel, however, some error will …


Parallel Real-Time Scheduling Of Dags, Abusayeed Saifullah, David Ferry, Jing Li, Kunal Agrawal, Chenyang Lu, Christopher Gill Jan 2013

Parallel Real-Time Scheduling Of Dags, Abusayeed Saifullah, David Ferry, Jing Li, Kunal Agrawal, Chenyang Lu, Christopher Gill

All Computer Science and Engineering Research

Recently, multi-core processors have become mainstream in processor design. To take full advantage of multi-core processing, computation-intensive real-time systems must exploit intra-task parallelism. In this paper, we address the open problem of real-time scheduling for a general model of deterministic parallel tasks, where each task is represented as a directed acyclic graph (DAG) with nodes having arbitrary execution requirements. We prove processor-speed augmentation bounds for both preemptive and non-preemptive real-time scheduling for general DAG tasks on multi-core processors. We first decompose each DAG into sequential tasks with their own release times and deadlines. Then we prove that these decomposed tasks …


Real-Time Multi-Core Virtual Machine Scheduling In Xen, Sisu Xi, Meng Xu, Chenyang Lu, Linh T.X. Phan, Christopher Gill, Olga Sokolsky, Insup Lee Jan 2013

Real-Time Multi-Core Virtual Machine Scheduling In Xen, Sisu Xi, Meng Xu, Chenyang Lu, Linh T.X. Phan, Christopher Gill, Olga Sokolsky, Insup Lee

All Computer Science and Engineering Research

Recent years have witnessed two major trends in the development of complex real-time systems. First, to reduce cost and enhance flexibility, multiple systems are sharing common computing platforms via virtualization technology, instead of being deployed separately on physically isolated hosts. Second, multicore processors are increasingly being used in real-time systems. The integration of real-time systems as virtual machines (VMs) atop common multicore platforms raises significant new research challenges in meeting the real-time performance requirements of multiple systems.


Efficient Parallel Real-Time Upsampling Of Ultrasound Vectors, William D. Richard Ph.D. Jan 2013

Efficient Parallel Real-Time Upsampling Of Ultrasound Vectors, William D. Richard Ph.D.

All Computer Science and Engineering Research

Upsampling is required prior to the summation step in most receive digital beamforming implementations to produce an accurate summed RF line or vector. This is true in both annular and linear array systems where receive echos are digitized first and then time delayed in the digital domain to achieve proper signal alignment. The efficient, parallel, real-time upsampling circuit presented here produces M upsampled values per ADC clock, where M is the desired upsampling factor. A circuit implementation that upsamples by a factor of M=4 is presented as an example of the more general technique.


Reconstruction Of Family-Level Phylogenetic Relationships Within Demospongiae (Porifera) Using Nuclear Encoded Housekeeping Genes, Malcolm S. Hill, April L. Hill, Jose V. Lopez, Kevin J. Peterson, Shirley Pomponi, Maria C. Diaz, Robert W. Thacker, Maja Adamska, Nicole Boury-Esnault, Paco Cárdenas, Andia Chaves-Fonnegra, Elizabeth Danka, Bre-Onna De Laine, Dawn Formica, Eduardo Hajdu, Gisele Lobo-Hajdu, Sarah Klontz, Christine C. Morrow, Jignasa Patel, Bernard Picton, Davide Pisani, Deborah Pohlmann, Niamh E. Redmond, John Reed, Stacy Richey, Ana Riesgo, Ewelina Rubin, Zach Russell, Klaus Rützler, Erik A. Sperling, Michael Di Stefano, James E. Tarver, Allen G. Collins Jan 2013

Reconstruction Of Family-Level Phylogenetic Relationships Within Demospongiae (Porifera) Using Nuclear Encoded Housekeeping Genes, Malcolm S. Hill, April L. Hill, Jose V. Lopez, Kevin J. Peterson, Shirley Pomponi, Maria C. Diaz, Robert W. Thacker, Maja Adamska, Nicole Boury-Esnault, Paco Cárdenas, Andia Chaves-Fonnegra, Elizabeth Danka, Bre-Onna De Laine, Dawn Formica, Eduardo Hajdu, Gisele Lobo-Hajdu, Sarah Klontz, Christine C. Morrow, Jignasa Patel, Bernard Picton, Davide Pisani, Deborah Pohlmann, Niamh E. Redmond, John Reed, Stacy Richey, Ana Riesgo, Ewelina Rubin, Zach Russell, Klaus Rützler, Erik A. Sperling, Michael Di Stefano, James E. Tarver, Allen G. Collins

Marine & Environmental Sciences Faculty Articles

Background: Demosponges are challenging for phylogenetic systematics because of their plastic and relatively simple morphologies and many deep divergences between major clades. To improve understanding of the phylogenetic relationships within Demospongiae, we sequenced and analyzed seven nuclear housekeeping genes involved in a variety of cellular functions from a diverse group of sponges.

Methodology/Principal Findings: We generated data from each of the four sponge classes (i.e., Calcarea, Demospongiae, Hexactinellida, and Homoscleromorpha), but focused on family-level relationships within demosponges. With data for 21 newly sampled families, our Maximum Likelihood and Bayesian-based approaches recovered previously phylogenetically defined taxa: Keratosap, …


A New List Of Cuban Crinoids (Echinodermata: Crinoidea), Ruber Rodriguez-Barreras, Charles G. Messing Jan 2013

A New List Of Cuban Crinoids (Echinodermata: Crinoidea), Ruber Rodriguez-Barreras, Charles G. Messing

Marine & Environmental Sciences Faculty Articles

This review is based on the most recent taxonomic classification of extant Cuban Crinoidea. Existing material in natural history collections in Cuba was analyzed in detail and accurately reflects species presence. The crinoid literature was also reviewed. Several previously unpublished observations of species found in waters off Cuba have also been included. This paper provides the most up to date description of the Cuban crinoid fauna. Habitat, distribution, depth range and localities in Cuba are reported for each species. Collection codes for available specimens are included when known. The work describes a total of 33 species (plus two subspecies) in …


Habitat Characterization, Distribution, And Areal Extent Of Deep-Sea Coral Ecosystems Off Florida, Southeastern U.S.A., John K. Reed, Charles G. Messing, Brian K. Walker, Sandra Brooke, Thiago B.S. Correa, Myra Brouwer, Tina Udouj, Stephanie Farrington Jan 2013

Habitat Characterization, Distribution, And Areal Extent Of Deep-Sea Coral Ecosystems Off Florida, Southeastern U.S.A., John K. Reed, Charles G. Messing, Brian K. Walker, Sandra Brooke, Thiago B.S. Correa, Myra Brouwer, Tina Udouj, Stephanie Farrington

Marine & Environmental Sciences Faculty Articles

The deep-sea (200-1000 m) seafloor off the southeastern U.S. has a variety of extensive deep-sea coral ecosystem (DSCE) habitats including: deep-water coral mounds; various hard-bottom habitats off Florida including the Miami Terrace, Pourtales Terrace, and deep-water canyons (Agassiz and Tortugas Valleys); and deep island slopes off western Bahamas and northern Cuba. The dominant structure-forming scleractinian corals are Lophelia pertusa and Enallopsammia profunda; other structure-forming taxa include stylasterid corals, gorgonians, black corals, and sponges. This biota is associated with hard-bottom seafloor of variable high-relief topography which can be remotely identified from bathymetric data. NOAA bathymetric contour maps and digital elevation …


Characterization Of The Heart Transcriptome Of The White Shark (Carcharodon Carcharias), Vincent P. Richards, Haruo Suzuki, Michael J. Stanhope, Mahmood S. Shivji Jan 2013

Characterization Of The Heart Transcriptome Of The White Shark (Carcharodon Carcharias), Vincent P. Richards, Haruo Suzuki, Michael J. Stanhope, Mahmood S. Shivji

Marine & Environmental Sciences Faculty Articles

Background: The white shark (Carcharodon carcharias) is a globally distributed, apex predator possessing physical, physiological, and behavioral traits that have garnered it significant public attention. In addition to interest in the genetic basis of its form and function, as a representative of the oldest extant jawed vertebrate lineage, white sharks are also of conservation concern due to their small population size and threat from overfishing. Despite this, surprisingly little is known about the biology of white sharks, and genomic resources are unavailable. To address this deficit, we combined Roche-454 and Illumina sequencing technologies to characterize the first …


Evolution Of High Tooth Replacement Rates In Sauropod Dinosaurs, Michael D. D'Emic, John A. Whitlock, Kathlyn M. Smith, Daniel C. Fisher, Jeffrey A. Wilson Jan 2013

Evolution Of High Tooth Replacement Rates In Sauropod Dinosaurs, Michael D. D'Emic, John A. Whitlock, Kathlyn M. Smith, Daniel C. Fisher, Jeffrey A. Wilson

School of Earth, Environment, and Sustainability Faculty Publications

Background: Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates.

Methodology/Principal Findings: We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined …


An Implicit Interface Boundary Integral Method For Poisson’S Equation On Arbitrary Domains, Catherine Kublik, Nicolay M. Tanushev, Richard Tsai Jan 2013

An Implicit Interface Boundary Integral Method For Poisson’S Equation On Arbitrary Domains, Catherine Kublik, Nicolay M. Tanushev, Richard Tsai

Mathematics Faculty Publications

We propose a simple formulation for constructing boundary integral methods to solve Poisson’s equation on domains with smooth boundaries defined through their signed distance function. Our formulation is based on averaging a family of parameterizations of an integral equation defined on the boundary of the domain, where the integrations are carried out in the level set framework using an appropriate Jacobian. By the coarea formula, the algorithm operates in the Euclidean space and does not require any explicit parameterization of the boundaries. We present numerical results in two and three dimensions.


Planetary Nebula Spectrograph Survey Of S0 Galaxy Kinematics – Ii. Clues To The Origins Of S0 Galaxies, A. Cortesi, M. R. Merrifield, L. Coccato, M. Arnaboldi, O. Gerhard, Aaron J. Romanowsky, N. G. Douglass, K. Kuiijken, M. Capaccioli, K. C. Freeman, K. Saha, A. L. Chies-Santos Jan 2013

Planetary Nebula Spectrograph Survey Of S0 Galaxy Kinematics – Ii. Clues To The Origins Of S0 Galaxies, A. Cortesi, M. R. Merrifield, L. Coccato, M. Arnaboldi, O. Gerhard, Aaron J. Romanowsky, N. G. Douglass, K. Kuiijken, M. Capaccioli, K. C. Freeman, K. Saha, A. L. Chies-Santos

Aaron J. Romanowsky

The stellar kinematics of the spheroids and discs of S0 galaxies contain clues to their formation histories. Unfortunately, it is difficult to disentangle the two components and to recover their stellar kinematics in the faint outer parts of the galaxies using conventional absorption line spectroscopy. This paper therefore presents the stellar kinematics of six S0 galaxies derived from observations of planetary nebulae, obtained using the Planetary Nebula Spectrograph. To separate the kinematics of the two components, we use a maximum-likelihood method that combines the discrete kinematic data with a photometric component decomposition. The results of this analysis reveal that: the …


Mond And Imf Variations In Early-Type Galaxies From Atlas3d, C. Tortora, Aaron J. Romanowsky, V. F. Cardone, N. R. Napolitano, Ph Jetzer Jan 2013

Mond And Imf Variations In Early-Type Galaxies From Atlas3d, C. Tortora, Aaron J. Romanowsky, V. F. Cardone, N. R. Napolitano, Ph Jetzer

Aaron J. Romanowsky

No abstract provided.


The Planetary Nebula Spectrograph Survey Of S0 Galaxy Kinematics. Data And Overview, A. Cortesi, M. Arnaboldi, L. Coccato, M. R. Merrifield, O. Gerhard, S. Bamford, Aaron J. Romanowsky, N. R. Napolitano, N. G. Douglas, K. Kuiijken, M. Capaccioli, K. C. Freeman, A. L. Chies-Santos, V. Pota Jan 2013

The Planetary Nebula Spectrograph Survey Of S0 Galaxy Kinematics. Data And Overview, A. Cortesi, M. Arnaboldi, L. Coccato, M. R. Merrifield, O. Gerhard, S. Bamford, Aaron J. Romanowsky, N. R. Napolitano, N. G. Douglas, K. Kuiijken, M. Capaccioli, K. C. Freeman, A. L. Chies-Santos, V. Pota

Aaron J. Romanowsky

The origins of S0 galaxies remain obscure, with various mechanisms proposed for their formation, likely depending on environment. These mechanisms would imprint different signatures in the galaxies' stellar kinematics out to large radii, offering a method for distinguishing between them. We aim to study a sample of six S0 galaxies from a range of environments, and use planetary nebulae (PNe) as tracers of their stellar populations out to very large radii, to determine their kinematics in order to understand their origins. Using a special-purpose instrument, the Planetary Nebula Spectrograph, we observe and extract PNe catalogues for these six systems*. We …


The Sluggs Survey: Wide Field Imaging Of The Globular Cluster System Of Ngc 4278, C. Usher, D. A. Forbes, L. R. Spitler, J. P. Brodie, Aaron J. Romanowsky, J. Strader, K. A. Woodley Jan 2013

The Sluggs Survey: Wide Field Imaging Of The Globular Cluster System Of Ngc 4278, C. Usher, D. A. Forbes, L. R. Spitler, J. P. Brodie, Aaron J. Romanowsky, J. Strader, K. A. Woodley

Aaron J. Romanowsky

We use multipointing Hubble Space Telescope Advanced Camera for Surveys and wide field Subaru Suprime-Cam imaging to study the globular cluster system of the L* elliptical galaxy NGC 4278. We have also obtained a handful of new globular cluster spectra with the Keck Deep Imaging Multi-Object Spectrograph. We determine the globular cluster surface density profile and use it to calculate the total number of globular clusters, finding the system to be slightly more populous than average for galaxies of its luminosity. We find clear evidence for bimodality in the globular cluster colour distribution and for a colour–magnitude relation in the …


Angular Momentum And Galaxy Formation Revisited: Effects Of Variable Mass-To-Light Ratios, S. M. Fall, Aaron J. Romanowsky Jan 2013

Angular Momentum And Galaxy Formation Revisited: Effects Of Variable Mass-To-Light Ratios, S. M. Fall, Aaron J. Romanowsky

Aaron J. Romanowsky

We rederive the relation between the specific angular momentum j sstarf and the mass M sstarf of the stellar matter in galaxies of different morphological types. This is a revision of the j sstarf-M sstarf diagram presented in our recent comprehensive study of galactic angular momentum. In that work, we estimated j sstarf from kinematic and photometric data that extended to large radii and M sstarf from near-infrared luminosities LK with an assumed universal mass-to-light ratio M sstarf/LK . However, recent stellar population models show large variations in M sstarf/LK correlated with B – V color. In the present work, …


Students Talk About Energy In Project- Based Inquiry Science, Benedikt W. Harrer, Virginia J. Flood, Michael C. Wittmann Jan 2013

Students Talk About Energy In Project- Based Inquiry Science, Benedikt W. Harrer, Virginia J. Flood, Michael C. Wittmann

Benedikt W. Harrer

We examine the types of emergent language eighth grade students in rural Maine middle schools use when they discuss energy in their first experiences with Project-Based Inquiry Science: Energy, a research-based curriculum that uses a specific language for talking about energy. By comparative analysis of the language used by the curriculum materials to students’ language, we find that students’ talk is at times more aligned with a Stores and Transfer model of energy than the Forms model supported by the curriculum.


Filling The Gap: A New Class Of Old Star Cluster?, D. A. Forbes, V. Pota, C. Usher, Aaron J. Romanowsky, J. Strader, J. P. Brodie, J. A. Arnold, L. R. Spitler Jan 2013

Filling The Gap: A New Class Of Old Star Cluster?, D. A. Forbes, V. Pota, C. Usher, Aaron J. Romanowsky, J. Strader, J. P. Brodie, J. A. Arnold, L. R. Spitler

Aaron J. Romanowsky

It is not understood whether long-lived star clusters possess a continuous range of sizes and masses (and hence densities) or if rather, they should be considered as distinct types with different origins. Utilizing the Hubble Space Telescope to measure sizes and long exposures on the Keck 10 m telescope to obtain distances, we have discovered the first confirmed star clusters that lie within a previously claimed size–luminosity gap dubbed the ‘avoidance zone’ by Hwang et al. The existence of these star clusters extends the range of sizes, masses and densities for star clusters, and argues against current formation models that …