Physical Sciences and Mathematics | Open Access Articles

Osaka University: A Focus Of Polymer Science: 70th Anniversary Celebration, Otto Vogl, Koichi Hatada

Otto Vogl

No abstract provided.

Personalities In Polymer Science: Cover Page, Title Page, Introduction, And List Of Articles, Otto Vogl

Otto Vogl

A compilation of articles with short biographies of the scientists who played leading roles in the field and provided the basis of Polymer Science and Technology throughout the 20th century.

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1. Yukio Imanishi, Otto Vogl

Otto Vogl

No abstract provided.

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A Study Of Indoor Carbon Dioxide Levels And Sick Leave Among Office Workers, Theodore A. Myatt, John W. Staudenmayer, Kate Adams, Michael Walters, Stephen N. Rudnick, Donald K. Milton

John W Staudenmayer

Background A previous observational study detected a strong positive relationship between sick leave absences and carbon dioxide (CO2) concentrations in office buildings in the Boston area. The authors speculated that the observed association was due to a causal effect associated with low dilution ventilation, perhaps increased airborne transmission of respiratory infections. This study was undertaken to explore this association. Methods We conducted an intervention study of indoor CO2 levels and sick leave among hourly office workers employed by a large corporation. Outdoor air supply rates were adjusted periodically to increase the range of CO2 concentrations. We recorded indoor CO2 concentrations …

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2. Toshinobu Higashimura, Otto Vogl

Otto Vogl

No abstract provided.

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A Discrete Nonlinear Model With Substrate Feedback, Panos Kevrekidis, B. A. Malomed, A. R. Bishop

Panos Kevrekidis

We consider a prototypical model in which a nonlinear field (continuum or discrete) evolves on a flexible substrate which feeds back to the evolution of the main field. We identify the underlying physics and potential applications of such a model and examine its simplest one-dimensional Hamiltonian form, which turns out to be a modified Frenkel-Kontorova model coupled to an extra linear equation. We find static kink solutions and study their stability, and then examine moving kinks (the continuum limit of the model is studied too). We observe how the substrate effectively renormalizes properties of the kinks. In particular, a nontrivial …

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3. Otto Vogl, Gerald S. Kirshenbaum, Helga Roder

Otto Vogl

No abstract provided.

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Medusae Fossae Formation: New Perspectives From Mars Global Surveyor, Bethany Bradley, S. E.H Sakimoto, H. Frey, J. R. Zimbelman

Bethany Bradley

The nature and origin of the Medusae Fossae Formation (MFF) on Mars has been debated since the return of the first Viking images. The MFF's young age, distinctive surface texture, and lack of obvious source have prompted multiple hypotheses for its origin. This study uses data from the Mars Global Surveyor (MGS) mission to examine the MFF at all available scales. We discuss and quantify observations from Mars Orbiter Laser Altimeter (MOLA) topography and Mars Orbiter Camera (MOC) images to better constrain the origin of the MFF. Topographic grid estimates yield a present extent of 2.1 × 106 km2 and …

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Review Of Frank Ryan: Tuberculosis: The Greatest Story Never Told, Lynn Margulis

Lynn Margulis (1938 - 2011)

No abstract provided.

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On The Minimum Ropelength Of Knots And Links, Jason Cantarella, Robert B. Kusner, John M. Sullivan

Robert Kusner

The ropelength of a knot is the quotient of its length by its thickness, the radius of the largest embedded normal tube around the knot. We prove existence and regularity for ropelength minimizers in any knot or link type; these are C 1,1 curves, but need not be smoother. We improve the lower bound for the ropelength of a nontrivial knot, and establish new ropelength bounds for small knots and links, including some which are sharp.

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Impervious Surfaces And Water Quality: A Review Of Current Literature And Its Implications For Watershed Planning, Elizabeth Brabec

Elizabeth Brabec

Impervious surfaces have for many years been recognized as an indicator of the intensity of the urban environment and, with the advent of urban sprawl, they have become a key issue in habitat health. Although a considerable amount of research has been done to define impervious thresholds for water quality degradation, there are a number of flaws in the assumptions and methodologies used. Given refinement of the methodology, accurate and usable parameters for preventative watershed planning can be developed, which include impervious surface thresholds and a balance between pervious and impervious surfaces within a watershed.

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Agricultural Land Fragmentation: The Spatial Effects Of Three Land Protection Strategies In The Eastern United States, Elizabeth Brabec, Chip Smith

Elizabeth Brabec

Fragmentation of agricultural land by urban sprawl affects both the agricultural production capacity of the land and its rural scenic quality. In order to assess the resulting fragmentation of the three most common types of agricultural land conservation tools in the United States, this study analyzes the spatial form of three land protection strategies: a purchase of development rights (PDR) program, a clustering program and a transfer of development rights program. By assessing a series of measures of success such as total acreage protected, size of parcels, contiguity and farming status, the study compares the effectiveness of programs that have …

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Star Formation In Bright Rimmed Clouds. I. Millimeter And Submillimeter Molecular Line Surveys, Christopher H. De Vries, Gopal Narayanan, Ronald L. Snell

Gopal Narayanan

We present the results of the first detailed millimeter and submillimeter molecular line survey of bright-rimmed clouds, observed at FCRAO in the CO (J = 1 ? 0), C18O (J = 1 ? 0), HCO+ (J = 1 ? 0), H13CO+ (J = 1 ? 0), and N2H+ (J = 1 ? 0) transitions, and at the Heinrich Hertz Telescope in the CO (J = 2 ? 1), HCO+ (J = 3 ? 2), HCO+ (J = 4 ? 3), H13CO+ (J = 3 ? 2), and H13CO+ (J = 4 ? 3) molecular line transitions. The source list is …

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Detection Of Infall Signatures Towards Serpens Smm4, Gopal Narayanan, G. Moriarty-Schieven, C.K. Walker, H.M. Butner

Gopal Narayanan

We present the detection of kinematic infall signatures toward the Class 0 protostellar system SMM4 in the Serpens cloud core. We have observed the dense molecular gas toward the embedded source using millimeter and submillimeter line transitions of density sensitive molecular tracers. High signal-to-noise ratio maps obtained in HCO+ J = 1 → 0, J = 3 → 2, and J = 4 → 3, and CS J = 2 → 1 show the blue-bulge infall signature. The blue-bulge infall signature can be observed in the centroid velocity maps of protostellar objects when infall dominates over rotation. The line profiles …

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Low Latitude Ice Cores Record Pacific Sea Surface Temperatures, Raymond S. Bradley, M. Vuille, D. R. Hardy, L. G. Thompson

Raymond S Bradley

Oxygen isotope variations in ice cores from Bolivia and Peru are highly correlated with sea surface temperatures (SSTs) across the equatorial Pacific Ocean, which are closely linked to ENSO variability. Circulation anomalies associated with this variability control moisture flux from the equatorial and tropical Atlantic Ocean and Amazon Basin to the ice core sites. Below average SSTs lead to higher accumulation rates and isotopically lighter snow; such conditions are also associated with lower atmospheric freezing levels. During warm events, opposite conditions prevail. Oxygen isotope variations in an ice core from the Himalayas also reflect SST variations in the equatorial Pacific …

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On Thickness And Packing Density For Knots And Links, Robert Kusner

Robert Kusner

We describe some problems, observations, and conjectures concerning density of the hexagonal packing of unit disks in R2.thickness and packing density of knots and links in S3 and R3. We prove the thickness of a nontrivial knot or link in S3 is no more than 4 , the thickness of a Hopf link. We also give arguments and evidence supporting the conjecture that the packing density of thick links in R3 or S3 is generally less than √12 , the density of the hexagonal packing of unit disks in R2.

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Ripening Of Porous Media, Benny Davidovitch, Deniz Ertas, Thomas C. Halsey

Benny Davidovitch

We address the surface tension-driven dynamics of porous media in nearly saturated pore-space solutions. We linearize this dynamics in the reaction-limited regime near its fixed points – surfaces of constant mean curvature (CMC surfaces). We prove that the only stable interface for this dynamics is the plane, and estimate the time scale for a CMC surface to become unstable. We also discuss the differences between open and closed system dynamics, pointing out the unlikelihood that CMC surfaces are ever realized in these systems on any time scale.

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Discrete Nonlinear Model With Substrate Feedback, P. G. Kevrekidis, B. A. Malomed, A. R. Bishop

Panos Kevrekidis

We consider a prototypical model in which a nonlinear field (continuum or discrete) evolves on a flexible substrate which feeds back to the evolution of the main field. We identify the underlying physics and potential applications of such a model and examine its simplest one-dimensional Hamiltonian form, which turns out to be a modified Frenkel-Kontorova model coupled to an extra linear equation. We find static kink solutions and study their stability, and then examine moving kinks (the continuum limit of the model is studied too). We observe how the substrate effectively renormalizes properties of the kinks. In particular, a nontrivial …

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Invaded Cluster Simulations Of The Xy Model In Two And Three, I. Dukovski, Jonathan Machta, L. V. Chayes

Jonathan Machta

The invaded cluster algorithm is used to study the XY model in two and three dimensions up to sizes 20002 and 1203, respectively. A soft spin O(2) model, in the same universality class as the three-dimensional XY model, is also studied. The static critical properties of the model and the dynamical properties of the algorithm are reported. The results are Kc=0.45412(2) for the three-dimensional XY model and η=0.037(2) for the three-dimensional XY universality class. For the two-dimensional XY model the results are Kc=1.120(1) and η=0.251(5). The invaded cluster algorithm does not show any critical slowing for the magnetization or critical …

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Iterated Conformal Dynamics And Laplacian Growth, Felipe Barra, Benny Davidovitch, Itamar Procaccia

Benny Davidovitch

The method of iterated conformal maps for the study of diffusion limited aggregates (DLA) is generalized to the study of Laplacian growth patterns and related processes. We emphasize the fundamental difference between these processes: DLA is grown serially with constant size particles, while Laplacian patterns are grown by advancing each boundary point in parallel, proportional to the gradient of the Laplacian field. We introduce a two-parameter family of growth patterns that interpolates between DLA and a discrete version of Laplacian growth. The ultraviolet putative finite-time singularities are regularized here by a minimal tip size, equivalently for all the models in …

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Quantum Corrections To The Reissner–Nordström And Kerr-Newman Metrics, John Donoghue, Barry R. Holstein, Björn Garbrecht, Thomas Konstandin

John Donoghue

We use effective field theory techniques to examine the quantum corrections to the gravitational metrics of charged particles, with and without spin. In momentum space the masslessness of the photon implies the presence of non-analytic pieces , q2log(−q2), etc. in the form factors of the energy–momentum tensor. We show how the former reproduces the classical non-linear terms of the Reissner–Nordström and Kerr–Newman metrics while the latter can be interpreted as quantum corrections to these metrics, of order Gαℏ/mr3

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On The Reducibility Of Characteristic Varieties, Tom Braden

Tom Braden

We show that some monodromies in the Morse local systems of a conically stratified perverse sheaf imply that other Morse local systems for smaller strata do not vanish. This result is then used to explain the examples of reducible characteristic varieties of Schubert varieties given by Kashiwara and Saito in type A and by Boe and Fu for the Lagrangian Grassmannian.

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A Smooth Space Of Tetrahedra, E Babson, Pe Gunnells, R Scott

Paul Gunnells

This is the pre-published version harvested from ArXiv. We construct a smooth symmetric compactification of the space of all labeled tetrahedra in 3.

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Statistical Issues In The Clustering Of Gene Expression Data, Darlene R. Goldstein, Debashis Ghosh, Erin M. Conlon

Erin M. Conlon

This paper illustrates some of the problems which can occur in any data set when clustering samples of gene expression profiles. These include a possible high degree of dependence of results on choice of clustering algorithm, further dependence of results on the choices of genes and samples to be included in the clustering (for example, whether or not to include control samples), and difficulty in assessing the validity of the grouping. We also demonstrate the use of Cox regression as a tool to identify genes influencing survival.

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Dynamical Superfluid-Insulator Transition In A Chain Of Weakly Coupled Bose-Einstein Condensates, A Smerzi, A Trombettoni, Panos Kevrekidis

Panos Kevrekidis

We predict a dynamical classical superfluid-insulator transition in a Bose-Einstein condensate trapped in an optical and a magnetic potential. In the tight-binding limit, this system realizes an array of weakly coupled condensates driven by an external harmonic field. For small displacements of the parabolic trap about the equilibrium position, the condensates coherently oscillate in the array. For large displacements, the condensates remain localized on the side of the harmonic trap with a randomization of the relative phases. The superfluid-insulator transition is due to a discrete modulational instability, occurring when the condensate center of mass velocity is larger than a critical …

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Nonequivalent Statistical Equilibrium Ensembles And Refined Stability Theorems For Most Probable Flows, Richard S. Ellis, Kyle Haven, Bruce Turkington

Richard S. Ellis

Statistical equilibrium models of coherent structures in two-dimensional and barotropic quasi-geostrophic turbulence are formulated using canonical and microcanonical ensembles, and the equivalence or nonequivalence of ensembles is investigated for these models. The main results show that models in which the energy and circulation invariants are treated microcanonically give richer families of equilibria than models in which they are treated canonically. For each model, a variational principle that characterizes its equilibrium states is derived by large deviation techniques. An analysis of the two different variational principles resulting from the canonical and microcanonical ensembles reveals that their equilibrium states coincide if and …

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Coiling Instabilities Of Multilamellar Tubes, Christian Santangelo, P. Pincus

Christian Santangelo

Myelin figures are densely packed stacks of coaxial cylindrical bilayers that are unstable to the formation of coils or double helices. These myelin figures appear to have no intrinsic chirality. We show that such cylindrical membrane stacks can develop an instability when they acquire a spontaneous curvature or when the equilibrium distance between membranes is decreased. This instability breaks the chiral symmetry of the stack and may result in coiling. A unilamellar cylindrical vesicle, on the other hand, will develop an axisymmetric instability, possibly related to the pearling instability.

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Fluctuations Of The Entropy Production In Anharmonic Chains, L Rey-Bellet, L Thomas

Luc Rey-Bellet

We prove the Gallavotti-Cohen fluctuation theorem for a model of heat conduction through a chain of anharmonic oscillators coupled to two Hamiltonian reservoirs at different temperatures.

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Paleoclimate Studies Of Minerogenic Sediments Using Annually Resolved Textural Parameters, Pierre Francus, Raymond S. Bradley, Mark B. Abbott, Whit Patridge, Frank Keimig

Raymond S Bradley

We obtained quantitative multivariate data from each varve of a minerogenic lacustrine sequence from the Canadian High Arctic, using an image analysis technique applied to thin-sections. The information on each varve from the uppermost core section was compared with a 35 yr meteorological dataset. Snowmelt intensity, which is an index reflecting the energy available for sediment transport, correlates well with the median grain-size measured for each varve, as well as with the weight of the 10–20 and 20–60 mm fractions. The proportion of fine silt also correlates with low intensity summer precipitation. This methodology allows us to decipher the climatic …

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Solar Influences On Cosmic Rays And Cloud Formation: A Reassessment, B. Sun, Raymond S. Bradley

Raymond S Bradley

Svensmark and Friis-Christensen [1997] proposed a “cosmic ray-cloud cover” hypothesis that cosmic ray flux, modulated by solar activity, may modify global cloud cover and thus global surface temperature by increasing the number of ions in the atmosphere, leading to enhanced condensation of water vapor and cloud droplet formation. We evaluate this idea by extending their period of study and examining long-term surface-based cloud data (from national weather services and the Global Telecommunication System) as well as newer satellite data (International Satellite Cloud Climatology Project (ISCCP) D2, 1983–1993). No meaningful relationship is found between cosmic ray intensity and cloud cover over …

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Full-Text Articles in Physical Sciences and Mathematics

Osaka University: A Focus Of Polymer Science: 70th Anniversary Celebration, Otto Vogl, Koichi Hatada

Otto Vogl

Personalities In Polymer Science: Cover Page, Title Page, Introduction, And List Of Articles, Otto Vogl

Otto Vogl

1. Yukio Imanishi, Otto Vogl

Otto Vogl

A Study Of Indoor Carbon Dioxide Levels And Sick Leave Among Office Workers, Theodore A. Myatt, John W. Staudenmayer, Kate Adams, Michael Walters, Stephen N. Rudnick, Donald K. Milton

John W Staudenmayer

2. Toshinobu Higashimura, Otto Vogl

Otto Vogl

A Discrete Nonlinear Model With Substrate Feedback, Panos Kevrekidis, B. A. Malomed, A. R. Bishop

Panos Kevrekidis

3. Otto Vogl, Gerald S. Kirshenbaum, Helga Roder

Otto Vogl

Medusae Fossae Formation: New Perspectives From Mars Global Surveyor, Bethany Bradley, S. E.H Sakimoto, H. Frey, J. R. Zimbelman

Bethany Bradley

Review Of Frank Ryan: Tuberculosis: The Greatest Story Never Told, Lynn Margulis

Lynn Margulis (1938 - 2011)

On The Minimum Ropelength Of Knots And Links, Jason Cantarella, Robert B. Kusner, John M. Sullivan

Robert Kusner

Impervious Surfaces And Water Quality: A Review Of Current Literature And Its Implications For Watershed Planning, Elizabeth Brabec

Elizabeth Brabec

Agricultural Land Fragmentation: The Spatial Effects Of Three Land Protection Strategies In The Eastern United States, Elizabeth Brabec, Chip Smith

Elizabeth Brabec

Star Formation In Bright Rimmed Clouds. I. Millimeter And Submillimeter Molecular Line Surveys, Christopher H. De Vries, Gopal Narayanan, Ronald L. Snell

Gopal Narayanan

Detection Of Infall Signatures Towards Serpens Smm4, Gopal Narayanan, G. Moriarty-Schieven, C.K. Walker, H.M. Butner

Gopal Narayanan

Low Latitude Ice Cores Record Pacific Sea Surface Temperatures, Raymond S. Bradley, M. Vuille, D. R. Hardy, L. G. Thompson

Raymond S Bradley

On Thickness And Packing Density For Knots And Links, Robert Kusner

Robert Kusner

Ripening Of Porous Media, Benny Davidovitch, Deniz Ertas, Thomas C. Halsey

Benny Davidovitch

Discrete Nonlinear Model With Substrate Feedback, P. G. Kevrekidis, B. A. Malomed, A. R. Bishop

Panos Kevrekidis

Invaded Cluster Simulations Of The Xy Model In Two And Three, I. Dukovski, Jonathan Machta, L. V. Chayes

Jonathan Machta

Iterated Conformal Dynamics And Laplacian Growth, Felipe Barra, Benny Davidovitch, Itamar Procaccia

Benny Davidovitch

Quantum Corrections To The Reissner–Nordström And Kerr-Newman Metrics, John Donoghue, Barry R. Holstein, Björn Garbrecht, Thomas Konstandin

John Donoghue

On The Reducibility Of Characteristic Varieties, Tom Braden

Tom Braden

A Smooth Space Of Tetrahedra, E Babson, Pe Gunnells, R Scott

Paul Gunnells

Statistical Issues In The Clustering Of Gene Expression Data, Darlene R. Goldstein, Debashis Ghosh, Erin M. Conlon

Erin M. Conlon

Dynamical Superfluid-Insulator Transition In A Chain Of Weakly Coupled Bose-Einstein Condensates, A Smerzi, A Trombettoni, Panos Kevrekidis

Panos Kevrekidis

Nonequivalent Statistical Equilibrium Ensembles And Refined Stability Theorems For Most Probable Flows, Richard S. Ellis, Kyle Haven, Bruce Turkington

Richard S. Ellis

Coiling Instabilities Of Multilamellar Tubes, Christian Santangelo, P. Pincus

Christian Santangelo

Fluctuations Of The Entropy Production In Anharmonic Chains, L Rey-Bellet, L Thomas

Luc Rey-Bellet

Paleoclimate Studies Of Minerogenic Sediments Using Annually Resolved Textural Parameters, Pierre Francus, Raymond S. Bradley, Mark B. Abbott, Whit Patridge, Frank Keimig

Raymond S Bradley

Solar Influences On Cosmic Rays And Cloud Formation: A Reassessment, B. Sun, Raymond S. Bradley

Raymond S Bradley