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2009

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Articles 4771 - 4800 of 7615

Full-Text Articles in Physical Sciences and Mathematics

Deep U Band And R Imaging Of Goods-South: Observations,Data Reduction And First Results, M. Nonino, M. Dickinson, P. Rosati, A. Grazian, N. Reddy, S. Cristiani, Mauro Giavalisco, H. Kuntschner, E. Vanzella, E. Daddi, C. Cesarsky Jan 2009

Deep U Band And R Imaging Of Goods-South: Observations,Data Reduction And First Results, M. Nonino, M. Dickinson, P. Rosati, A. Grazian, N. Reddy, S. Cristiani, Mauro Giavalisco, H. Kuntschner, E. Vanzella, E. Daddi, C. Cesarsky

Mauro Giavalisco

We present deep imaging in the {\em U} band covering an area of 630 arcmin$^{2}$ centered on the southern field of the Great Observatories Origins Deep Survey (GOODS). The data were obtained with the VIMOS instrument at the ESO Very Large Telescope. The final images reach a magnitude limit $U_{lim} \approx 29.8$ (AB, 1$\sigma$, in a 1\arcsec radius aperture), and have good image quality, with full width at half maximum $\approx 0.8\arcsec$. They are significantly deeper than previous U--band images available for the GOODS fields, and better match the sensitivity of other multi--wavelength GOODS photometry. The deeper U--band data yield …

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Uv Continuum Slope And Dust Obscuration From Z~6 To Z~2: The Star Formation Rate Density At High Redshift, R. J. Bouwens, G. D. Illingworth, M. Franx, R.-R. Chary, G. R. Meurer, C. J. Conselice, H. Ford, Mauro Giavalisco, P. Van Dokkum Jan 2009

Uv Continuum Slope And Dust Obscuration From Z~6 To Z~2: The Star Formation Rate Density At High Redshift, R. J. Bouwens, G. D. Illingworth, M. Franx, R.-R. Chary, G. R. Meurer, C. J. Conselice, H. Ford, Mauro Giavalisco, P. Van Dokkum

Mauro Giavalisco

We provide a systematic measurement of the rest-frame UV continuum slope beta over a wide range in redshift (z~2-6) and rest-frame UV luminosity (0.1-2L*) to improve estimates of the SFR density at high redshift. We utilize the deep optical and infrared data (ACS/NICMOS) over the CDF-S and HDF-N GOODS fields, as well as the UDF for our primary UBVi "dropout" sample. We correct the observed distributions for selection biases and photometric scatter. We find that the UV-continuum slope of the most luminous galaxies is substantially redder at z~2-4 than it is at z~5-6. Lower luminosity galaxies are also found to …

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The Unusual Niv]-Emitter Galaxy Gds J033218.92-275302.7: Star Formation Or Agn-Driven Winds From A Massive Galaxy At Z=5.56, E. Vanzella, A. Grazian, M. Hayes, L. Pentericci, D. Schaerer, M. Dickinson, S. Cristiani, Mauro Giavalisco, A. Verhamme, M. Nonino, P. Rosati Jan 2009

The Unusual Niv]-Emitter Galaxy Gds J033218.92-275302.7: Star Formation Or Agn-Driven Winds From A Massive Galaxy At Z=5.56, E. Vanzella, A. Grazian, M. Hayes, L. Pentericci, D. Schaerer, M. Dickinson, S. Cristiani, Mauro Giavalisco, A. Verhamme, M. Nonino, P. Rosati

Mauro Giavalisco

Aims: We investigate the nature of the source GDS J033218.92-275302.7at redshift ~ 5.56. Methods: The SED of the source is well sampled by 16 bands photometry, from UV-optical, near infrared and mid-infrared (MID-IR).The detection of signal in the MID-IR Spitzer/IRAC bands 5.8, 8.0 um -- where the nebular emission contribution is less effective -- suggests the presence of a Balmer break, signature of an underlying stellar population formed at earlier epochs. The optical spectrum shows a clear Lya emission line together with semi-forbidden NIV] 1483.3-1486.5 also in emission. Results: From the SED fitting and the Lya modelling it turns out …

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Hst/Acs Morphology Of Lyman Alpha Emitters At Redshift 5.7 In The Cosmos Field, Y. Taniguchi, T. Murayama, N. Z. Scoville, S. S. Sasaki, T. Nagao, Y. Shioya, T. Saito, Y. Ideue, A. Nakajima, K. Matsuoka, D. B. Sanders, B. Mobasher, H. Aussel, P. Capak, M. Salvato, K. Koekemoer, C. Carilli, A. Cimatti, R. S. Ellis, B. Garilli, Mauro Giavalisco, O. Ilbert, C. D. Impey, M. G. Kitzbilcher, O. Le Fevre, H. J. Mccracken, C. Scarlata, E. Schinnerer, V. Smolcic, S. Tribiano, J. R. Trump Jan 2009

Hst/Acs Morphology Of Lyman Alpha Emitters At Redshift 5.7 In The Cosmos Field, Y. Taniguchi, T. Murayama, N. Z. Scoville, S. S. Sasaki, T. Nagao, Y. Shioya, T. Saito, Y. Ideue, A. Nakajima, K. Matsuoka, D. B. Sanders, B. Mobasher, H. Aussel, P. Capak, M. Salvato, K. Koekemoer, C. Carilli, A. Cimatti, R. S. Ellis, B. Garilli, Mauro Giavalisco, O. Ilbert, C. D. Impey, M. G. Kitzbilcher, O. Le Fevre, H. J. Mccracken, C. Scarlata, E. Schinnerer, V. Smolcic, S. Tribiano, J. R. Trump

Mauro Giavalisco

We present detailed morphological properties of Lyman alpha emitters (LAEs) at z~ 5.7 in the COSMOS field, based on {\it Hubble Space Telescope} Advanced Camera for Surveys (ACS) data. The ACS imaging in the F814W filter covered 85 LAEs of the 119 LAEs identified in the full two square degree field, and 47 LAEs of them are detected in the ACS images. Nearly half of them are spatially extended with a size larger than 0.15 arcsec (~0.88 kpc at z=5.7) up to 0.4 arcsec (~2.5 kpc at z=5.7). The others are nearly unresolved compact objects. Two LAEs show double-component structures, …

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Evidence For A Fast Evolution Of The Uv Luminosity Function Beyond Redshift 6 From A Deep Hawk-I Survey Of The Goods-S Field, M. Castellano, A. Fontana, K. Boutsia, A. Grazian, L. Pentericci, R. Bouwens, M. Dickinson, Mauro Giavalisco, P. Santini, S. Cristiani, F. Fiore, S. Gallozzi, E. Giallongo, R. Maiolino, F. Mannucci, N. Menci, A. Moorwood, M. Nonino, D. Paris, A. Renzini, P. Rosati, S. Salimbeni, V. Testa, E. Vanzella Jan 2009

Evidence For A Fast Evolution Of The Uv Luminosity Function Beyond Redshift 6 From A Deep Hawk-I Survey Of The Goods-S Field, M. Castellano, A. Fontana, K. Boutsia, A. Grazian, L. Pentericci, R. Bouwens, M. Dickinson, Mauro Giavalisco, P. Santini, S. Cristiani, F. Fiore, S. Gallozzi, E. Giallongo, R. Maiolino, F. Mannucci, N. Menci, A. Moorwood, M. Nonino, D. Paris, A. Renzini, P. Rosati, S. Salimbeni, V. Testa, E. Vanzella

Mauro Giavalisco

We perform a deep search for galaxies in the redshift range 6.51, Y-J<1.5 and Y-K<2. The other public data in the UBVRIJHK bands are used to reject possible low redshift interlopers. The output has been compared with extensive Monte Carlo simulations to quantify the observational effects of our selection criteria as well as the effects of photometric errors. We detect 7 high quality candidates in the magnitude range Y=25.5-26.7. This interval samples the critical range for M* at z>6 (M_1500 ~- 19.5 to -21.5). After accounting for the expected incompleteness, we rule out at a 99% confidence level a Luminosity Function constant from z=6 to z=7, even including the effects of cosmic variance. For galaxies brighter than M_1500=-19.0 we derive a luminosity density rho_UV=1.5^{+2.0}_{-0.9} 10^25 erg/s/Hz/Mpc3, implying a decrease by a factor 3.5 from z=6 to z~6.8. On the basis of our findings, we make predictions for the surface densities expected in future surveys surveys, based on ULTRA-VISTA, HST-WFC3 or JWST-NIRCam, evaluating the best observational …

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A Percolation-Theoretic Approach To Spin Glass Phase Transitions, Jonathan Machta, C. M. Newman, D. L. Stein Jan 2009

A Percolation-Theoretic Approach To Spin Glass Phase Transitions, Jonathan Machta, C. M. Newman, D. L. Stein

Jonathan Machta

The magnetically ordered, low temperature phase of Ising ferromagnets is manifested within the associated Fortuin—Kasteleyn (FK) random cluster representation by the occurrence of a single positive density percolating cluster. In this paper, we review our recent work on the percolation signature for Ising spin glass ordering — both in the short-range Edwards—Anderson (EA) and infinite-range Sherrington—Kirkpatrick (SK) models — within a tworeplica FK representation and also in the different Chayes—Machta—Redner two-replica graphical representation. Numerical studies of the ±J EA model in dimension three and rigorous results for the SK model are consistent in supporting the conclusion that the signature of …

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Multiattribute Optimization Of Restoration Options: Designing Incentives For Watershed Management, Timothy O. Randhir, Deborah M. Shriver Jan 2009

Multiattribute Optimization Of Restoration Options: Designing Incentives For Watershed Management, Timothy O. Randhir, Deborah M. Shriver

Timothy O. Randhir

Watershed restoration requires careful assessment of impairment in ecosystem attributes to design appropriate conservation policies. This study applies a multiattribute optimization framework for evaluating relative gains in restoration based on potential improvements in economic and environmental attributes related to water quality, habitat, and urbanization. Policy mechanisms through direct compensation of restoration activities are evaluated based on single-attribute and multiattribute optimization and watershed response to varying levels of restoration incentives. Results indicate that tradeoffs in economic and environmental objectives are critical to identifying optimal restoration strategies at a watershed scale. The multiattribute optimization method developed in this study balances levels of …

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On The Stellar Populations And Evolution Of Star-Forming Galaxies At 6.3 < Z < 8.6, Steven L. Finkelstein, Casey Papovich, Mauro Giavalisco, Naveen A. Reddy, Henry C. Ferguson, Anton M. Koekemoer, Mark Dickinson Jan 2009

On The Stellar Populations And Evolution Of Star-Forming Galaxies At 6.3 < Z < 8.6, Steven L. Finkelstein, Casey Papovich, Mauro Giavalisco, Naveen A. Reddy, Henry C. Ferguson, Anton M. Koekemoer, Mark Dickinson

Mauro Giavalisco

We study the physical characteristics of galaxies at 6.3 < z < 8.6, selected from deep near-infrared imaging with the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. Accounting for the photometric scatter using simulations, galaxies at z ~ 7 have bluer UV colors compared to typical local starburst galaxies at > 4 sigma confidence. Although these colors necessitate young ages (<100 Myr), low or zero dust attenuation, and low metallicities, these are explicable by normal (albeit unreddened) stellar populations, with no evidence for near-zero metallicities and/or top-heavy initial mass functions. The age of the Universe at these redshifts limits the amount of stellar mass in late-type populations, and the WFC3 photometry implies galaxy stellar masses ~ 10^8 - 10^9 Msol for Salpeter initial mass functions to a limiting magnitude of M_1500 ~ -18. The masses of ``characteristic'' (L*) z > 7 galaxies are smaller than those of L* Lyman break galaxies (LBGs) at lower redshifts, and are comparable to less evolved galaxies selected on the basis of their Lyman alpha emission at 3 < z < 6, implying that the 6.3 < z < 8.6 galaxies are the progenitors of more evolved galaxies at lower redshifts. We estimate that Lyman alpha emission is able to contribute to the observed WFC3 colors of galaxies at these redshifts, with an estimated typical line flux of ~ 10^-18 erg s^-1 cm^-2, roughly a factor of four below currently planned surveys. The integrated UV specific luminosity for the detected galaxies at z ~ 7 and z ~ 8 is within factors of a few of that required to reionize the IGM assuming low clumping factors, implying that in order to reionize the Universe galaxies at these redshifts have a high ( ~ 50%) escape fraction of Lyman continuum photons, possibly substantiated by the very blue colors of this population.

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Index To The Selected Works Of Otto Vogl, Otto Vogl Jan 2009

Index To The Selected Works Of Otto Vogl, Otto Vogl

Otto Vogl

No abstract provided.

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Meine Jugend In Traiskirchen, Otto Vogl Jan 2009

Meine Jugend In Traiskirchen, Otto Vogl

Otto Vogl

No abstract provided.

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Recent Changes In Freezing Level Heights In The Tropics With Implications For The Deglacierization Of High Mountain Regions, Raymond S. Bradley, F. Keimig, H. F. Diaz, D. R. Hardy Jan 2009

Recent Changes In Freezing Level Heights In The Tropics With Implications For The Deglacierization Of High Mountain Regions, Raymond S. Bradley, F. Keimig, H. F. Diaz, D. R. Hardy

Raymond S Bradley

The height of the freezing level in the tropical atmosphere (the free air 0°C isotherm) has increased across most of the region, particularly in the outer Tropics. In the tropical Andes, south of the Equator, high elevation surface temperatures and upper air data show a similar trend in temperature, of ∼0.1°C/decade over the last 50 years. Meteorological observations at 5680 m on the summit of the Quelccaya Ice Cap, the largest ice mass in the Tropics, indicate that daily maximum temperatures often exceed 0°C from October–May, and rise well above freezing for much of the year around the ice cap …

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Strengths And Weaknesses Of Parallel Tempering, Jonathan Machta Jan 2009

Strengths And Weaknesses Of Parallel Tempering, Jonathan Machta

Jonathan Machta

Parallel tempering, also known as replica exchange Monte Carlo, is studied in the context of two simple free-energy landscapes. The first is a double-well potential defined by two macrostates separated by a barrier. The second is a “golf course” potential defined by microstates having two possible energies with exponentially more high-energy states than low-energy states. The equilibration time for replica exchange is analyzed for both systems. For the double-well system, parallel tempering with a number of replicas that scales as the square root of the barrier height yields exponential speedup of the equilibration time. On the other hand, replica exchange …

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Capturing Data Uncertainty In High-Volume Stream Processing, Yanlei Diao, Boduo Li, Anna Liu, Liping Peng, Charles Sutton, Thanh Tran, Michael Zink Jan 2009

Capturing Data Uncertainty In High-Volume Stream Processing, Yanlei Diao, Boduo Li, Anna Liu, Liping Peng, Charles Sutton, Thanh Tran, Michael Zink

Anna Liu

We present the design and development of a data stream system that captures data uncertainty from data collection to query processing to final result generation. Our system focuses on data that is naturally modeled as continuous random variables such as many types of sensor data. To provide an end-to-end solution, our system employs probabilistic modeling and inference to generate uncertainty description for raw data, and then a suite of statistical techniques to capture changes of uncertainty as data propagates through query operators. To cope with high-volume streams, we explore advanced approximation techniques for both space and time efficiency. We are …

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Statistical Methods To Correct For Observation Error In A Density-Independent Population Model, John Buonaccorsi, J. Staudenmayer Jan 2009

Statistical Methods To Correct For Observation Error In A Density-Independent Population Model, John Buonaccorsi, J. Staudenmayer

John Buonaccorsi

The problem of observation error in assessing the dynamics of populations over time has received increasing attention of late. Of particular interest has been a density-independent dynamic model, which allows a trend and is commonly employed in population viability analysis (PVA). Most of the recent work in this area has focused on assessing the impact of the observation error and on finding corrected estimators, primarily under normal models with the observation errors assumed to have a constant variance. This paper provides a comprehensive overview of statistical methods for this problem and evaluates them through simulations. This includes the development and …

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Comments On The Minimal Vectorial Standard Model, Mohamed M. Anber, Ufuk Aydemir, John Donoghue, Preema Pais Jan 2009

Comments On The Minimal Vectorial Standard Model, Mohamed M. Anber, Ufuk Aydemir, John Donoghue, Preema Pais

John Donoghue

We explore the available parameter space of the minimal vectorial Standard Model. In this theory, the gauge currents are initially vectorial but the Higgs sector produces chiral mass eigenstates, leading to a set of heavy right-handed mirror particles. We describe the phenomenology of the residual parameter space and suggest that the model will be readily tested at the LHC.

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Fences Impede Long-Distance Mongolian Gazelle (Procapra Gutturosa) Movements In Drought-Stricken Landscapes, Kirk A. Olson, Thomas Mueller, Peter Leimgruber, Craig Nicolson, Todd K. Fuller, S. Bolortsetseg, Amanda E. Fine, B. Lhagvasuren, William F. Fagan Jan 2009

Fences Impede Long-Distance Mongolian Gazelle (Procapra Gutturosa) Movements In Drought-Stricken Landscapes, Kirk A. Olson, Thomas Mueller, Peter Leimgruber, Craig Nicolson, Todd K. Fuller, S. Bolortsetseg, Amanda E. Fine, B. Lhagvasuren, William F. Fagan

Craig Nicolson

Human-generated landscape barriers are especially problematic for species whose life histories entail long-distance movements. In May 2008, hundreds of Mongolian gazelles (Procapra gutturosa) became entangled in border fences as thousands attempted to move from Mongolia into Russia. Typically, the root cause of such (non-migratory) mass animal movements can only be superfi cially described. Here we draw upon satellite imagery and a fortuitously timed fi eld study to investigate a likely hypothesis. At the same time that gazelles were attempting to cross from Mongolia into Russia, gazelles equipped with satellite-linked collars repeatedly attempted to emigrate from Mongolia into China. Satellite-derived estimates …

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Stability, Toxicity And Differential Cellular Uptake Of Protein Passivated-Fe3o4 Nanoparticles, A Bajaj, B Samanta, Hh Yan, Dj Jerry, Vm Rotello Jan 2009

Stability, Toxicity And Differential Cellular Uptake Of Protein Passivated-Fe3o4 Nanoparticles, A Bajaj, B Samanta, Hh Yan, Dj Jerry, Vm Rotello

Vincent Rotello

We have explored the mechanism and differential uptake of BSA coated Fe3O4 nanoparticles (NPs) by different cancerous and isogenic cell types.

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Revisiting Melting Point Alternation In Hydrocarbons Using Pixel, Dhandapani Venkataraman Jan 2009

Revisiting Melting Point Alternation In Hydrocarbons Using Pixel, Dhandapani Venkataraman

Dhandapani Venkataraman

We revisit the explanations for the alternation in melting points of linear alkanes by calculating the lattice energies using PIXEL. The lattice energies obtained from PIXEL at optimal box radium are in excellent agreement with the enthalpy of sublimation. Partitioning of the lattice energy indicate that arguments based on the gain in dispersion energy is insufficient to explain the alternation in melting points in linear alkanes. Entropy of fusion plays a major role in the explanation for the observed melting point alternation in alkanes.

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Seasonal Source-Sink Dynamics At The Edge Of A Species’ Range, Todd K. Fuller, L. L. Kanda, P. R. Sievert, R. L. Kellogg Jan 2009

Seasonal Source-Sink Dynamics At The Edge Of A Species’ Range, Todd K. Fuller, L. L. Kanda, P. R. Sievert, R. L. Kellogg

Todd K. Fuller

The roles of dispersal and population dynamics in determining species' range boundaries recently have received theoretical attention but little empirical work. Here we provide data on survival, reproduction, and movement for a Virginia opossum (Didelphis virginiana) population at a local distributional edge in central Massachusetts (USA). Most juvenile females that apparently exploited anthropogenic resources survived their first winter, whereas those using adjacent natural resources died of starvation. In spring, adult females recolonized natural areas. A life-table model suggests that a population exploiting anthropogenic resources may grow, acting as source to a geographically interlaced sink of opossums using only natural resources, …

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Quantifying Total And Sustainable Agricultural Biomass Resources In South Dakota—A Preliminary Assessment, Kurt A. Rosentrater, Dennis Todey, Russell Persyn Jan 2009

Quantifying Total And Sustainable Agricultural Biomass Resources In South Dakota—A Preliminary Assessment, Kurt A. Rosentrater, Dennis Todey, Russell Persyn

Kurt A. Rosentrater

Conversion of biomass is considered the next major advance in biorenewable fuels, energy, and products. Wholesale conversion to biomass utilization could result in removal of current crop residues from agricultural fields (on prime agricultural lands) or even implementation of different crops and cropping strategies (i.e., switchgrass on marginal lands). To date, the driver for biomass processing has been economics and limitations on the conversion of the lignocellulose. Over the last forty years significant investments and resultant changes in management practices in the agricultural sector have focused on soil and water conservation. One of the major efforts has focused on conservation-till …

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Properties Of Solvent Extracted Low-Oil Corn Distillers Dried Grains With Solubles, Kurt A. Rosentrater, Jennifer A. Saunders Jan 2009

Properties Of Solvent Extracted Low-Oil Corn Distillers Dried Grains With Solubles, Kurt A. Rosentrater, Jennifer A. Saunders

Kurt A. Rosentrater

Corn-based ethanol is exponentially growing in the US, as is the need for valuable uses for coproducts of the production process, such as distillers dried grains with solubles (DDGS). Currently, DDGS is used as livestock feed, thereby replacing some corn components in animal diets. As the industry continues to grow, there will be an increased need to find additional uses for DDGS. Physical and chemical properties of coproduct streams are becoming increasingly investigated, as these characteristics affect many aspects of utilization, such as target species, optimal dietary substitution rates, transportation, flowability, and behavior during storage. Potential avenues for future use …

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Design Properties For Molded, Corn-Based Ddgs-Filled Phenolic Resin, R. A. Tatara, Kurt A. Rosentrater, S. Suraparaju Jan 2009

Design Properties For Molded, Corn-Based Ddgs-Filled Phenolic Resin, R. A. Tatara, Kurt A. Rosentrater, S. Suraparaju

Kurt A. Rosentrater

With the rapid growth in the ethanol fuel industry in recent years, considerable research is being devoted to maximizing the use of processing coproducts, such as distillers dried grains with solubles (DDGS), typically for livestock diets. Because these residues contain high fiber levels, they may be amendable to incorporation into polymers as well, which is an option that could garner greater economic returns. Thus, the goal of this study was to demonstrate the viability of using corn-based DDGS as a biofiller with phenolic resin, in order to produce a novel biomaterial. DDGS was blended with phenolic resin at four levels …

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Comparing Glacial And Holocene Opal Fluxes In The Pacific Sector Of The Southern Ocean, Louisa I. Bradtmiller, Robert F. Anderson, Martin Q. Fleisher, Lloyd H. Burckle Jan 2009

Comparing Glacial And Holocene Opal Fluxes In The Pacific Sector Of The Southern Ocean, Louisa I. Bradtmiller, Robert F. Anderson, Martin Q. Fleisher, Lloyd H. Burckle

Louisa I. Bradtmiller

No abstract provided.

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The Death Of The Model T: Smooth Roads, Closed Cars, And Technological Maladaption; A Translation Of "La Morte Del Modello T: Strade Pavimentate, Auto Coperte E Tecnologica Desueta", Christopher Wells Jan 2009

The Death Of The Model T: Smooth Roads, Closed Cars, And Technological Maladaption; A Translation Of "La Morte Del Modello T: Strade Pavimentate, Auto Coperte E Tecnologica Desueta", Christopher Wells

Christopher W. Wells

No abstract provided.

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Establishing The Quantitative Thinking Program At Macalester, David Bressoud Jan 2009

Establishing The Quantitative Thinking Program At Macalester, David Bressoud

David Bressoud

No abstract provided.

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Maa To Probe Calculus I, David Bressoud Jan 2009

Maa To Probe Calculus I, David Bressoud

David Bressoud

No abstract provided.

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Is The Sky Still Falling?, David Bressoud Jan 2009

Is The Sky Still Falling?, David Bressoud

David Bressoud

No abstract provided.

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Review Of “Continuum Modeling In The Physical Sciences” By Van Groesen And Molenaar, Chad M. Topaz Jan 2009

Review Of “Continuum Modeling In The Physical Sciences” By Van Groesen And Molenaar, Chad M. Topaz

Chad M. Topaz

No abstract provided.

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Asymptotic Dynamics Of Attractive-Repulsive Swarms, Andrew Leverentz, Chad M. Topaz, Andrew J. Bernoff Jan 2009

Asymptotic Dynamics Of Attractive-Repulsive Swarms, Andrew Leverentz, Chad M. Topaz, Andrew J. Bernoff

Chad M. Topaz

We classify and predict the asymptotic dynamics of a class of swarming models. The model consists of a conservation equation in one dimension describing the movement of a population density field. The velocity is found by convolving the density with a kernel describing attractive-repulsive social interactions. The kernel's first moment and its limiting behavior at the origin determine whether the population asymptotically spreads, contracts, or reaches steady-state. For the spreading case, the dynamics approach those of the porous medium equation. The widening, compactly-supported population has edges that behave like traveling waves whose speed, density and slope we calculate. For the …

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Mind The Gap, David Bressoud Jan 2009

Mind The Gap, David Bressoud

David Bressoud

No abstract provided.

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