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2000

University of Massachusetts Amherst

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Articles 1 - 30 of 128

Full-Text Articles in Physical Sciences and Mathematics

Constant Mean Curvature Surfaces With Three Ends, Karsten Grosse-Brauckmann, Robert Kusner, John M. Sullivan Dec 2000

Constant Mean Curvature Surfaces With Three Ends, Karsten Grosse-Brauckmann, Robert Kusner, John M. Sullivan

Robert Kusner

We announce the classification of complete almost embedded surfaces of constant mean curvature, with three ends and genus zero. They are classified by triples of points on the sphere whose distances are the asymptotic necksizes of the three ends.


Temporal Changes In The Observed Relationship Between Cloud Cover And Surface Air Temperature, Bomin Sun, Pavel Ya. Groisman, Raymond S. Bradley, Frank T. Keimig Dec 2000

Temporal Changes In The Observed Relationship Between Cloud Cover And Surface Air Temperature, Bomin Sun, Pavel Ya. Groisman, Raymond S. Bradley, Frank T. Keimig

Raymond S Bradley

The relationship between cloud cover and near-surface air temperature and its decadal changes are examined using the hourly synoptic data for the past four to six decades from five regions of the Northern Hemisphere: Canada, the United States, the former Soviet Union, China, and tropical islands of the western Pacific. The authors define the normalized cloud cover–surface air temperature relationship, NOCET or dT/dCL, as a temperature anomaly with a unit (one-tenth) deviation of total cloud cover from its average value. Then mean monthly NOCET time series (night- and daytime, separately) are area-averaged and parameterized as functions of surface air humidity …


5. Burton Carl Anderson, Otto Vogl Dec 2000

5. Burton Carl Anderson, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


5. Burton Carl Anderson, Otto Vogl Dec 2000

5. Burton Carl Anderson, Otto Vogl

Otto Vogl

No abstract provided.


Mean Annual Temperature Trends And Their Vertical Structure In The Tropical Andes, Mathias Yuille, Raymond S. Bradley Dec 2000

Mean Annual Temperature Trends And Their Vertical Structure In The Tropical Andes, Mathias Yuille, Raymond S. Bradley

Raymond S Bradley

Mean annual temperature trends in the tropical Andes were determined over the last six decades ( 1939-1998), to investigate the apparent inconsistency between the observed glacier retreat and the reported slight cooling trend in the lower tropical troposphere after 1979. Our results indicate that temperature in the tropical Andes has increased by 0. 10° - 0. I l °C/decade since 1939. The rate of warming has more than tripled over the last 25 years (0.32° - 0.34 °C/decade) and the last two years of the series, associated with the 1997/98 El Nino, were the warmest of the last six decades. …


An Excursion From Enumerative Geometry To Solving Systems Of Polynomial Equations With Macaulay 2, Frank Sottile Nov 2000

An Excursion From Enumerative Geometry To Solving Systems Of Polynomial Equations With Macaulay 2, Frank Sottile

Mathematics and Statistics Department Faculty Publication Series

Solving a system of polynomial equations is a ubiquitous problem in the applications of mathematics. Until recently, it has been hopeless to find explicit solutions to such systems, and mathematics has instead developed deep and powerful theories about the solutions to polynomial equations. Enumerative Geometry is concerned with counting the number of solutions when the polynomials come from a geometric situation and Intersection Theory gives methods to accomplish the enumeration. We use Macaulay 2 to investigate some problems from enumerative geometry, illustrating some applications of symbolic computation to this important problem of solving systems of polynomial equations. Besides enumerating solutions …


6. Ichitaro Uematsu, Otto Vogl, Teiji Tsuruta, Yoshiko Uematsu Nov 2000

6. Ichitaro Uematsu, Otto Vogl, Teiji Tsuruta, Yoshiko Uematsu

Emeritus Faculty Author Gallery

No abstract provided.


6. Ichitaro Uematsu, Otto Vogl, Teiji Tsuruta, Yoshiko Uematsu Nov 2000

6. Ichitaro Uematsu, Otto Vogl, Teiji Tsuruta, Yoshiko Uematsu

Otto Vogl

No abstract provided.


The Two Micron All-Sky Survey: Removing The Infrared Foreground, John E. Gizis, Michael F. Skrutskie Oct 2000

The Two Micron All-Sky Survey: Removing The Infrared Foreground, John E. Gizis, Michael F. Skrutskie

Astronomy Department Faculty Publication Series

We introduce the properties of the Two Micron All-Sky Survey (2MASS) survey for IAU Symposium 204. 2MASS is a near-infrared survey of the entire sky characterized by high reliability and completeness. Catalogs and images for 47% of the sky are now available online. This data release has been used by Wright (2000) and Cambr´esy et al. (2000) to subtract the stellar foreground at 1.25 and 2.2 microns from COBE DIRBE data, revealing the cosmological near-infrared background.


Canaleparolina Darwiniensis, Gen. Nov., Sp. Nov., And Other Pillotinaceae Spirochetes From Insects, Andrew Wier, Jon Ashen, Lynn Margulis Sep 2000

Canaleparolina Darwiniensis, Gen. Nov., Sp. Nov., And Other Pillotinaceae Spirochetes From Insects, Andrew Wier, Jon Ashen, Lynn Margulis

Lynn Margulis (1938 - 2011)

We describe two new pillotinaceous spirochetes (Canaleparolina darwiniensis, Diplocalyx cryptotermitidis) and identify for the first time Hollandina pterotermitidisfrom both the subterranean termite Cryptotermes cavifrons and the wood-eating cockroach Cryptocercus punctulatus based on morphometric analysis of transmission electron micrographic thin sections. C. darwiniensis, gen. nov., sp. nov., limited to near Darwin, Australia, invariably is present on the surface of the treponeme-studded trichomonad Mixotricha paradoxa, a consistent inhabitant of the hindgut of healthy termite Mastotermes darwiniensis. The spirochete both attached to the surface of protists and free-swimming in the paunch (hindgut) lumen of the insect has 16 periplasmic flagella (16:32:16) and imbricated …


8. Paolo Corradini, Otto Vogl, Brigitta Griesbeck Corradini Sep 2000

8. Paolo Corradini, Otto Vogl, Brigitta Griesbeck Corradini

Emeritus Faculty Author Gallery

No abstract provided.


8. Paolo Corradini, Otto Vogl, Brigitta Griesbeck Corradini Sep 2000

8. Paolo Corradini, Otto Vogl, Brigitta Griesbeck Corradini

Otto Vogl

No abstract provided.


9. Oskar Friedrich Olaj, Otto Vogl Aug 2000

9. Oskar Friedrich Olaj, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


Dynamics Of Lattice Kinks, Panos Kevrekidis, M. I. Weinstein Aug 2000

Dynamics Of Lattice Kinks, Panos Kevrekidis, M. I. Weinstein

Panos Kevrekidis

In this paper we consider two models of soliton dynamics (the sine Gordon and the \phi^4 equations) on a 1-dimensional lattice. We are interested in particular in the behavior of their kink-like solutions inside the Peierls- Nabarro barrier and its variation as a function of the discreteness parameter. We find explicitly the asymptotic states of the system for any value of the discreteness parameter and the rates of decay of the initial data to these asymptotic states. We show that genuinely periodic solutions are possible and we identify the regimes of the discreteness parameter for which they are expected to …


9. Oskar Friedrich Olaj, Otto Vogl Aug 2000

9. Oskar Friedrich Olaj, Otto Vogl

Otto Vogl

No abstract provided.


10. Dietrich Braun, Otto Vogl Jul 2000

10. Dietrich Braun, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


10. Dietrich Braun, Otto Vogl Jul 2000

10. Dietrich Braun, Otto Vogl

Otto Vogl

No abstract provided.


Modular Symbols And Hecke Operators, Paul E. Gunnells Jun 2000

Modular Symbols And Hecke Operators, Paul E. Gunnells

Paul Gunnells

We survey techniques to compute the action of the Hecke operators on the cohomology of arithmetic groups. These techniques can be seen as generalizations in different directions of the classical modular symbol algorithm, due to Manin and Ash-Rudolph. Most of the work is contained in papers of the author and the author with Mark McConnell. Some results are unpublished work of Mark McConnell and Robert MacPherson.


Can We Protect Agricultural Land And The Scenic Rural Landscape? The Spatial Effects Of Three Land Protection Strategies In The Eastern United States, Elizabeth Brabec, Chip Smith Jun 2000

Can We Protect Agricultural Land And The Scenic Rural Landscape? The Spatial Effects Of Three Land Protection Strategies In The Eastern United States, Elizabeth Brabec, Chip Smith

Elizabeth Brabec

In order to assess the efficacy of the three most common types of agricultural land conservation in the United States, this study analyzes the spatial and visual quality of a purchase of development rights program and two regulatory programs — cluster and the transfer of development rights. The study compares the effectiveness of programs that have been in place for periods of 6 to 18 years, surveying three different communities in the urban fringe: 1. the transfer of development rights program in Montgomery County, Maryland, in effect since 1981, 2. Riverhead, New York’s farmland development rights acquisition program, administered by …


Fragmentation, Impervious Surfaces And Water Quality: Quantifying The Effects Of Density And Spatial Arrangement, Elizabeth Brabec, Paul Richards, Stacey Schulte Jun 2000

Fragmentation, Impervious Surfaces And Water Quality: Quantifying The Effects Of Density And Spatial Arrangement, Elizabeth Brabec, Paul Richards, Stacey Schulte

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. In addition to the direct impacts to water quality, impervious surfaces fragment open space and habitat and are therefore a primary land use indicator of both water quality and ecological degradation. This paper develops an understanding of the land use planning implications of the interaction of impervious surfaces, water quality and the spatial form those surfaces take in a watershed. In order to clarify these relationships, …


Orbifold Quantum Cohomology, Weimin Chen Chen, Yongbin Ruan Jun 2000

Orbifold Quantum Cohomology, Weimin Chen Chen, Yongbin Ruan

Weimin Chen

This is a research announcement on a theory of Gromov-Witten invariants and quantum cohomology of symplectic or projective orbifolds. Our project started in the summer of 98 where our original motivation was to study the quantum cohomology under singular flops in complex dimension three. In this setting, we allow our three-fold to have terminal singularities which can be deformed into a symplectic orbifold. We spent the second half of 98 and most of spring of 99 to develop the foundation of Gromov-Witten invariants over orbifolds, including the key conceptual ingredient — the notion of good map. In the April of …


11. Binglin He, Otto Vogl, Frank C. Ho (He Zhenchi) Jun 2000

11. Binglin He, Otto Vogl, Frank C. Ho (He Zhenchi)

Emeritus Faculty Author Gallery

No abstract provided.


11. Binglin He, Otto Vogl, Frank C. Ho (He Zhenchi) Jun 2000

11. Binglin He, Otto Vogl, Frank C. Ho (He Zhenchi)

Otto Vogl

No abstract provided.


Dust Emissions From High-Redshift Qsos, C L. Carilli, K M. Bertoldi, K M. Menten, M P. Rupen, E Kreysa, Xiaohui Fan, Michael A. Strauss, Donald P. Schneider, A Bertarini, Min S. Yun, R Zylka Apr 2000

Dust Emissions From High-Redshift Qsos, C L. Carilli, K M. Bertoldi, K M. Menten, M P. Rupen, E Kreysa, Xiaohui Fan, Michael A. Strauss, Donald P. Schneider, A Bertarini, Min S. Yun, R Zylka

Min S. Yun

We present detections of emission at 250 GHz (1.2 mm) from two high-redshift QSOs from the Sloan Digital Sky Survey sample using the bolometer array at the IRAM 30 m telescope. The sources are SDSSp 015048.831004126.2 at z = 3.7 and SDSSp J033829.311002156.3 at z = 5.0; the latter is the third highest redshift QSO known and the highest redshift millimeter-emitting source yet identified. We also present deep radio continuum imaging of these two sources at 1.4 GHz using the Very Large Array. The combination of centimeter and millimeter observations indicate that the 250 GHz emission is most likely thermal …


Research Ethics: An Introduction, Tom Regan Apr 2000

Research Ethics: An Introduction, Tom Regan

Ethics in Science and Engineering National Clearinghouse

Research Ethics: an Introduction focuses both on how Responsible Conduct of Research (RCR) fits into the field of applied ethics and on procedures for making decisions that have a moral component. Tom Regan presents “Morally Relevant Questions: A Check List” with the central theme of balancing conflicting obligations. We expand this discussion with several classic resources by well known experts in research ethics that articulate critical topics. We present a Case Study from The Association for Practical and Professional Ethics. We consider the question of professional codes and think about the toll of making the right decision. In the Additional …


The Mentoring Of Graduate Students, Margaret King Apr 2000

The Mentoring Of Graduate Students, Margaret King

Ethics in Science and Engineering National Clearinghouse

The Mentoring of Graduate Students presents basic issues that face both mentors and their protégés. Margaret King, the Graduate School, is our faculty guide for this module. We focus on some of the ethical values most central to the mentoring process such as justice and the idea of contracts. One of the challenges of the mentoring experience is that it involves rules and practices both tangible and intangible. Dr. King explores some of these intangibles- Right Attention, Right Balance, Right Empowerment and Right Boundaries- in the central essay and we focus on them additionally in our Central Theme section. We …


Responsible Authorship And Peer Review, James Wilson Apr 2000

Responsible Authorship And Peer Review, James Wilson

Ethics in Science and Engineering National Clearinghouse

Responsible Authorship and Peer Review presents the basic issues facing researchers at the publication stage of research. We focus on some of the ethical values particularly relevant to publication: honesty, objectivity, trust, collegiality, and the problem of power differentials. We present Jim Wilson’s Guidelines for Authors and the Office of Research Integrity (ORI) Guidelines: ORI has also posted extensive materials on authorship and peer review issues. We present a Case Study from The Association for Practical and Professional Ethics. We consider the challenges of peer review, especially in terms of innovation in research. In the Resources section, you will find …


Professional Responsibility And Codes Of Conduct, Nell Kriesberg Apr 2000

Professional Responsibility And Codes Of Conduct, Nell Kriesberg

Ethics in Science and Engineering National Clearinghouse

Professional Responsibility and Codes of Conduct presents an overview of major issues concerning professionalism as they relate to the Responsible Conduct of Research (RCR). Joe Herkert emphasizes both the micro (between individuals) and macro (between professionals and society) ethical dimensions of professional responsibility and codes of conduct. We compare ethical codes with aspects of moral theory, expanding the discussion with some of the classical readings for this topic. We present a case study from the Association for Practical and Professional Ethics. We consider the complex issue of whistle-blowing. We close with a sampling of additional resources.


Human Subjects In Research, Matt Ronning Apr 2000

Human Subjects In Research, Matt Ronning

Ethics in Science and Engineering National Clearinghouse

Human Subjects in Research presents basic ethical issues that face researchers when doing work with human participants. Matt Ronning, Assistant Vice Chancellor for Research Administration Sponsored Programs and Regulatory Compliance, (SPARCS) is our guide for this module. In the Overview section we review chapters from two well known textbooks on Research Ethics. In the Applied Ethics section we focus on the consent form as a contract and comment upon the recurring topics of Justice and Honesty as they apply particularly to human subjects. In the Central Theme section we review institutional guidelines, both at the national and institutional level, utilizing …


Rightdoing And Misconduct In Research, Rebeca Rufty, Nell Kriesberg Apr 2000

Rightdoing And Misconduct In Research, Rebeca Rufty, Nell Kriesberg

Ethics in Science and Engineering National Clearinghouse

Rightdoing and Research presents the major issues concerning research integrity and misconduct; we intend this to be more of a reference handbook than the other modules in the series. Our faculty expert for this module is Becky Rufty, the Graduate School. Concepts of Rightdoing and integrity are discussed, and we expand the discussion with several key articles in the evolution of research ethics literature. Ethical concerns about ambiguity and trust are explored, as is the idea of micro and Macroethics. We focus on the resources at NC State University for promoting research integrity, as well as national guidelines. We present …