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2002

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Articles 2521 - 2550 of 3435

Full-Text Articles in Physical Sciences and Mathematics

Mixed-Symmetry Shell-Model Calculations In Nuclear Physics, Vesselin Gueorguiev Gueorguiev Jan 2002

Mixed-Symmetry Shell-Model Calculations In Nuclear Physics, Vesselin Gueorguiev Gueorguiev

LSU Doctoral Dissertations

Advances in computer technologies allow calculations in ever larger model spaces. To keep our understanding growing along with this growth in computational power, we consider a novel approach to the nuclear shell model. The one-dimensional harmonic oscillator in a box is used to introduce the concept of an oblique-basis shell-model theory. By implementing the Lanczos method for diagonalization of large matrices, and the Cholesky algorithm for solving generalized eigenvalue problems, the method is applied to nuclei. The mixed-symmetry basis combines traditional spherical shell-model states with SU(3) collective configurations. We test the validity of this mixed-symmetry scheme on 24Mg and …


Enumeration Of Matchings In The Incidence Graphs Of Complete And Complete Bipartite Graphs, Nicholas Pippenger Jan 2002

Enumeration Of Matchings In The Incidence Graphs Of Complete And Complete Bipartite Graphs, Nicholas Pippenger

All HMC Faculty Publications and Research

If G = (V, E) is a graph, the incidence graphI(G) is the graph with vertices I E and an edge joining vV and eE when and only when v is incident with e in G. For G equal to Kn (the complete graph on n vertices) or Kn,n (the complete bipartite graph on n + n vertices), we enumerate the matchings (sets of edges, no two having a vertex in common) in I(G), both exactly (in terms of generating …


Women In Physics In The United States, Megan Urry, Sheila Tobias, Kim Budil, Howard Georgi, Kristine Lang, Dongqi Li, Laurie Mcneil, Peter N. Saeta, Jennifer Sokoloski, Sharon Stephenson, Aparna Venkatesan, Yevgeniya Zastavker Jan 2002

Women In Physics In The United States, Megan Urry, Sheila Tobias, Kim Budil, Howard Georgi, Kristine Lang, Dongqi Li, Laurie Mcneil, Peter N. Saeta, Jennifer Sokoloski, Sharon Stephenson, Aparna Venkatesan, Yevgeniya Zastavker

All HMC Faculty Publications and Research

Presents an overview of the status of women in physics in the U.S. Under-representation of women; Highlights of the report 'Women in Physics, 2000'; Efforts to increase the number of women in the profession; Issues for women activists.


The Large M Limit Of Non-Commutative Open Strings At Strong Coupling, Vatche Sahakian Jan 2002

The Large M Limit Of Non-Commutative Open Strings At Strong Coupling, Vatche Sahakian

All HMC Faculty Publications and Research

Two-dimensional Non-Commutative Open String (NCOS) theory, well-defined perturbatively, may also be studied at strong coupling and for large D-string charge by making use of the Holographic duality. We analyze the zero mode dynamics of a closed string in the appropriate background geometry and map the results onto a sector of strongly coupled NCOS dynamics. We find an elaborate classical picture that shares qualitative similarities with the SL(2,R) WZW model. In the quantum problem, we compute propagators and part of the energy spectrum of the theory; the latter involves interesting variations in the density of states as a function …


Article Are Hydrogen Bonds Unique Among Weak Interactions In Their Ability To Mediate Electronic Coupling?, Emily Cukier '03, Sarah Daniels '02, Eric Vinson '01, Robert J. Cave Jan 2002

Article Are Hydrogen Bonds Unique Among Weak Interactions In Their Ability To Mediate Electronic Coupling?, Emily Cukier '03, Sarah Daniels '02, Eric Vinson '01, Robert J. Cave

All HMC Faculty Publications and Research

Superexchange effects on the electronic coupling element for electron transfer are investigated using water dimers and atomic donors and acceptors. We compare the electronic coupling elements obtained with H-bonded dimers to those obtained for other water dimer geometries at given donor−acceptor and oxygen−oxygen distances. The H-bonded orientation does not yield significantly different coupling elements from non-H-bonded orientations at a given oxygen−oxygen distance. In addition, the distance dependence of the coupling mediated by H-bonds is not significantly different from that for other dimer geometries. It is found that protonation of the intervening waters has a significant effect on coupling elements for …


Time-Dependent Density Functional Theory Investigation Of The Ground And Excited States Of Coumarins 102, 152, 153, And 343, Robert J. Cave, Edward W. Castner Jr. Jan 2002

Time-Dependent Density Functional Theory Investigation Of The Ground And Excited States Of Coumarins 102, 152, 153, And 343, Robert J. Cave, Edward W. Castner Jr.

All HMC Faculty Publications and Research

We present calculations of various properties of the ground and excited electronic states of coumarins 102, 152, 153, and 343. Using density functional theory (DFT) and time-dependent density functional theory (TDDFT), we examine the excitation energies to the S1 and S2 states, the ground and excited-state dipole moments, and the lowest ionization potentials of these coumarins. In the case of C153, we locate two distinct S0 minima due to differing conformations of the julolidyl ring structure and compare properties for the syn and anti conformers. For C343, we examine the possibility of proton transfers in the ground …


A Minimal Regular Ring Extension Of C(X), Melvin Henriksen, Robert M. Raphael, R. G. Woods Jan 2002

A Minimal Regular Ring Extension Of C(X), Melvin Henriksen, Robert M. Raphael, R. G. Woods

All HMC Faculty Publications and Research

Let G(X) denote the smallest (von Neumann) regular ring of real-valued functions with domain X that contains C(X), the ring of continuous real-valued functions on a Tikhonov topological space (X,Τ). We investigate when G(X) coincides with the ring C(X,Τδ) of continuous real-valued functions on the space (X,Τδ), where Τδ is the smallest Tikhonov topology on X for which tau subset of or equal to tau(delta) and C(X,Τδ) is von Neumann regular. The compact and metric spaces for which G(X) = C(X,Τδ) are characterized. Necessary, and different sufficient, conditions for the equality …


Fluorescence And Chromospheric Activity Of V471 Tau, Todd R. Vaccaro, Robert E. Wilson Jan 2002

Fluorescence And Chromospheric Activity Of V471 Tau, Todd R. Vaccaro, Robert E. Wilson

Physics and Astronomy Faculty Publications

The red dwarf + white dwarf eclipsing binary V471 Tau shows a variable Hα feature that varies from absorption during eclipse to maximum emission during white dwarf transit. In 1998 we obtained simultaneous BVRI photometry and Hα spectroscopy, with thorough phase coverage of the 12.5 hour orbital period. A binary star model was used with our light curve, radial velocity, and Hα data to refine stellar and orbital parameters. Combined absorption-emission profiles were generated by the model and fit to the observations, yielding a red star radius of 0.94⊙. Orbital inclination 78° is required with this size and other known …


Multiyear Increases In Dissolved Organic Matter Inventories At Station Aloha In The North Pacific Subtropical Gyre, Mj Church, Hw Ducklow, Dm Karl Jan 2002

Multiyear Increases In Dissolved Organic Matter Inventories At Station Aloha In The North Pacific Subtropical Gyre, Mj Church, Hw Ducklow, Dm Karl

VIMS Articles

The inventories and dynamics of dissolved organic matter (DOM) in the surface water at Station ALOHA were analyzed from the Hawaii Ocean Time-series (HOT) data set for the period 1989-1999. Euphotic zone, depth-integrated (0-175 m) concentrations of dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) were temporally variable. In particular, during the period 1993-1999, concentrations of DOC and DON increased while inventories of DOP remained unchanged. DOC inventories increased by 303 mmol C m(-2) yr(-1), a value equivalent to approximately 2% of measured primary production (C-14 method) at this site. DON increased at 11 mmol N m(-2) yr(-1), resulting …


Kentucky River Basin Management Plan, Kentucky Water Resources Research Institute Jan 2002

Kentucky River Basin Management Plan, Kentucky Water Resources Research Institute

KWRRI Research Reports

This report summarizes how agency activities will be coordinated in the Kentucky River basin during the fiver year cycle beginning in July 2002. It sets out the criteria and processes that guide state and federal programs to take particular actions.


Fiber Optic Sensor Response To High Levels Of Fat In Cream, Czarena L. Crofcheck, Frederick A. Payne, Clair L. Hicks, M. Pinar Mengüç, Sue E. Nokes Jan 2002

Fiber Optic Sensor Response To High Levels Of Fat In Cream, Czarena L. Crofcheck, Frederick A. Payne, Clair L. Hicks, M. Pinar Mengüç, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

A light backscatter technique using optical fibers to deliver and receive light was investigated for measuring the milkfat content of unhomogenized cream. Light backscatter through cream at wavelengths of 450 to 900 nm was measured for fiber separation distances from 2 to 6.5 mm and for cream containing 10 to ~40 weight percent (wt%) milkfat. Unhomogenized cream (~40 wt% milkfat) was mixed with skim milk (~0.05 wt% milkfat) to yield samples with five different milkfat levels. Three optical response models were tested for correlation with milkfat content: one using the light intensity measurement at a single separation distance, the second …


Renewal Theory For Uniform Random Variables, Steven Robert Spencer Jan 2002

Renewal Theory For Uniform Random Variables, Steven Robert Spencer

Theses Digitization Project

This project will focus on finding formulas for E[N(t)] using one of the classical problems in the discipline first, and then extending the scope of the problem to include overall times greater than the time t in the original problem. The expected values in these cases will be found using the uniform and exponential distributions of random variables.


Cognitive Rehab Solutions: A Computer-Assisted Cognitive Training Program, Avani Rajnikant Patel Jan 2002

Cognitive Rehab Solutions: A Computer-Assisted Cognitive Training Program, Avani Rajnikant Patel

Theses Digitization Project

The purpose of this project is to offer a functionally comprehensive application, Cognitive Rehab Solutions (CRS), that is designed for neuropsychologists to deliver restorative cognitive training in areas of attention and memory of persons with brain impairment.


Egyptian Fractions, Jodi Ann Hanley Jan 2002

Egyptian Fractions, Jodi Ann Hanley

Theses Digitization Project

Egyptian fractions are what we know as unit fractions that are of the form 1/n - with the exception, by the Egyptians, of 2/3. Egyptian fractions have actually played an important part in mathematics history with its primary roots in number theory. This paper will trace the history of Egyptian fractions by starting at the time of the Egyptians, working our way to Fibonacci, a geologist named Farey, continued fractions, Diophantine equations, and unsolved problems in number theory.


Progress On Geoenvironmental Models For Selected Mineral Deposit Types, Robert R. Seal Ii, Nora K. Foley Jan 2002

Progress On Geoenvironmental Models For Selected Mineral Deposit Types, Robert R. Seal Ii, Nora K. Foley

United States Geological Survey: Publications

Since the beginning of economic geology as a subdiscipline of the geological sciences, economic geologists have tended to classify mineral deposits on the basis of geological, mineralogical, and geochemical criteria, in efforts to systematize our understanding of mineral deposits as an aid to exploration. These efforts have lead to classifications based on commodity, geologic setting (Cox and Singer, 1986), inferred temperatures and pressures of ore formation (Lindgren, 1933), and genetic setting (Park and MacDiarmid, 1975; Jensen and Bateman, 1979). None of these classification schemes is mutually exclusive; instead, there is considerable overlap among all of these classifications. A natural outcome …


Development Of A Circa 2000 Landcover Database For The United States, Collin Homer, Chengquan Huang, Limin Yang, Bruce K. Wylie Jan 2002

Development Of A Circa 2000 Landcover Database For The United States, Collin Homer, Chengquan Huang, Limin Yang, Bruce K. Wylie

United States Geological Survey: Publications

Multi-Resolution Land Characterization 2000 (MRLC 2000) is a second-generation federal consortium to create an updated pool of nation-wide Landsat 7 imagery, and derive a second-generation National Land Cover Database (NLCD 2000). This multi-layer, multisource database will include a suite of 30-meter resolution data that will serve as standardized ingredients for the production of land cover – both nationally and locally. This database will also provide the framework to allow flexibility in developing and applying suites of independent data layers. These nationally standardized independent data layers or components, will be useful not only within the land-cover classification but as data themes …


Derivation Of A Tasseled Cap Transformation Based On Landsat 7 At-Satellite Reflectance, C. Huang, Bruce K. Wylie, Limin Yang, Collin Homer, Gregory Zylstra Jan 2002

Derivation Of A Tasseled Cap Transformation Based On Landsat 7 At-Satellite Reflectance, C. Huang, Bruce K. Wylie, Limin Yang, Collin Homer, Gregory Zylstra

United States Geological Survey: Publications

A new tasseled cap transformation based on Landsat 7 at-satellite reflectance was developed. This transformation is most appropriate for regional applications where atmospheric correction is not feasible. The brightness, greenness and wetness of the derived transformation collectively explained over 97% of the spectral variance of the individual scenes used in this study.


Assessment Of Elemental Concentrations In Streams Of The New Lead Belt In Southeastern Missouri, 2002–05, William G. Brumbaugh, Thomas W. May, John M. Besser, Ann L. Allert, Christopher J. Schmitt Jan 2002

Assessment Of Elemental Concentrations In Streams Of The New Lead Belt In Southeastern Missouri, 2002–05, William G. Brumbaugh, Thomas W. May, John M. Besser, Ann L. Allert, Christopher J. Schmitt

United States Geological Survey: Publications

Concerns about possible effects of lead-mining activities on the water quality of federally protected streams located in southeastern Missouri prompted a suite of multidisciplinary studies to be conducted by the U.S. Geological Survey. As part of this investigation, a series of biological studies were initiated in 2001 for streams in the current mining region and the prospecting area. In this report, results are examined for trace elements and other selected chemical measurements in sediment, surface water, and sediment interstitial (pore) water sampled between 2002 and 2005 in association with these biological studies. Compared to reference sites, fine sediments collected downstream …


Intermittent Turbulence Associated With A Density Current Passage In The Stable Boundary Layer, Jielun Sun, Sean P. Burns, Donald H. Lenschow, Robert Banta, Rob Newsom, Richard Coulter, Stephen Fraiser, Carmen Nappo, Joan Cuxart, William Blumen, Xuhui Lee, Xin-Zhang Hu Jan 2002

Intermittent Turbulence Associated With A Density Current Passage In The Stable Boundary Layer, Jielun Sun, Sean P. Burns, Donald H. Lenschow, Robert Banta, Rob Newsom, Richard Coulter, Stephen Fraiser, Carmen Nappo, Joan Cuxart, William Blumen, Xuhui Lee, Xin-Zhang Hu

United States Department of Commerce: Staff Publications

Using the unprecedented observational capabilities deployed during the Cooperative Atmosphere-Surface Exchange Study-99 (CASES-99), we found three distinct turbulence events on the night of 18 October 1999, each of which was associated with different phenomena: a density current, solitary waves, and downward propagating waves from a low-level jet. In this study, we focus on the first event, the density current and its associated intermittent turbulence. As the cold density current propagated through the CASES-99 site, eddy motions in the upper part of the density current led to periodic overturning of the stratified flow, local thermal instability and a downward diffusion of …


Chemical Contaminants In Juvenile Gray Whales (Eschrichtius Robustus) From A Subsistence Harvest In Arctic Feeding Grounds, Karen L. Tilbury, John E. Stein, Cheryl A. Krone, Robert L. Brownell Jr., S.A. Blokhin, Jennie L. Bolton, Don W. Ernest Jan 2002

Chemical Contaminants In Juvenile Gray Whales (Eschrichtius Robustus) From A Subsistence Harvest In Arctic Feeding Grounds, Karen L. Tilbury, John E. Stein, Cheryl A. Krone, Robert L. Brownell Jr., S.A. Blokhin, Jennie L. Bolton, Don W. Ernest

United States Department of Commerce: Staff Publications

Gray whales are coastal migratory baleen whales that are benthic feeders. Most of their feeding takes place in the northern Pacific Ocean with opportunistic feeding taking place during their migrations and residence on the breeding grounds. The concentrations of organochlorines and trace elements were determined in tissues and stomach contents of juvenile gray whales that were taken on their Arctic feeding grounds in the western Bering Sea during a Russian subsistence harvest. These concentrations were compared to previously published data for contaminants in gray whales that stranded along the west coast of the US during their northbound migration. Feeding in …


Dynamics Of The Lake Michigan Food Web, 1970–2000, Charles P. Madenjian, Gary L. Fahnenstiel, Thomas H. Johengen, Thomas F. Nalepa, Henry A. Vanderploeg, Guy W. Fleischer, Philip J. Schneeberger, Darren M. Benjamin, Emily B. Smith, James R. Bence, Edward S. Rutherford, Dennis S. Lavis, Dale M. Robertson, David J. Jude, Mark P. Ebener Jan 2002

Dynamics Of The Lake Michigan Food Web, 1970–2000, Charles P. Madenjian, Gary L. Fahnenstiel, Thomas H. Johengen, Thomas F. Nalepa, Henry A. Vanderploeg, Guy W. Fleischer, Philip J. Schneeberger, Darren M. Benjamin, Emily B. Smith, James R. Bence, Edward S. Rutherford, Dennis S. Lavis, Dale M. Robertson, David J. Jude, Mark P. Ebener

United States Department of Commerce: Staff Publications

Herein, we document changes in the Lake Michigan food web between 1970 and 2000 and identify the factors responsible for these changes. Control of sea lamprey (Petromyzon marinus) and alewife (Alosa pseudoharengus) populations in Lake Michigan, beginning in the 1950s and 1960s, had profound effects on the food web. Recoveries of lake whitefish (Coregonus clupeaformis) and burbot (Lota lota) populations, as well as the buildup of salmonine populations, were attributable, at least in part, to sea lamprey control. Based on our analyses, predation by salmonines was primarily responsible for the reduction in …


Dispersal And Emerging Ecological Impacts Of Ponto-Caspian Species In The Laurentian Great Lakes, Henry A. Vanderploeg, Thomas F. Nalepa, David J. Jude, Edward L. Mills, Kristen T. Holeck, James R. Liebig, Igor A. Grigorovich, Henn Ojaveer Jan 2002

Dispersal And Emerging Ecological Impacts Of Ponto-Caspian Species In The Laurentian Great Lakes, Henry A. Vanderploeg, Thomas F. Nalepa, David J. Jude, Edward L. Mills, Kristen T. Holeck, James R. Liebig, Igor A. Grigorovich, Henn Ojaveer

United States Department of Commerce: Staff Publications

We describe, explain, and “predict” dispersal and ecosystem impacts of six Ponto-Caspian endemic species that recently invaded the Great Lakes via ballast water. The zebra mussel, Dreissena polymorpha, and quagga mussel, Dreissena bugensis, continue to colonize hard and soft substrates of the Great Lakes and are changing ecosystem function through mechanisms of ecosystem engineering (increased water clarity and reef building), fouling native mussels, high particle filtration rate with selective rejection of colonial cyanobacteria in pseudofeces, alteration of nutrient ratios, and facilitation of the rapid spread of their Ponto-Caspian associates, the benthic amphipod Echinogammarus ischnus and the round goby, …


Optical And Magnetic Behaviour Of Low Dimensional Structures, Francis Pedreschi Jan 2002

Optical And Magnetic Behaviour Of Low Dimensional Structures, Francis Pedreschi

Doctoral

Low dimensional structures can exhibit unusual properties due to the quantum confinement of electrons. This may manifest itself in any effects that depend on electron behaviour. In this study, the optical and magnetic properties in particular of two types of low dimensional structures are examines. Quantum wires are structures that have macroscopic length scales along one dimension and nanometre length scales in the others. Two Indium induced reconstructions of Silicon surfaces were grown and examined to determine if quantum confinement, a necessary requirement for a quantum wire, did exist for their structures. A UHV compatible Reflectance Anisotropy Spectroscopy (RAS) instrument, …


The Probe, Issue 220 – January/February 2002 Jan 2002

The Probe, Issue 220 – January/February 2002

The Probe: Newsletter of the National Animal Damage Control Association

HSUS Draft Recommendations For the Oversight of Wildlife Control Operators -- Arthur E. Smith
One-hundred and forty five persons attended the 8th Annual Wildlife Control Instructional Seminar, in Las Vegas, February 4-6. The seminar was sponsored by Wildlife Control Technology (WCT) and the National Wildlife Control Operators Association (NWCOA).
Attending "Regular" Fish and Wildlife Conferences -- Chad Richardson:” I think the wildlife damage field should get back into the practice of attending and presenting at these conferences.”
Book Review: Joy and Celebration of Mole Control by Jeff Holper.
NATIONAL ANIMAL DAMAGE CONTROL ASSOCIATION 2002 Membership Directory
The Arizona office of …


Techniques For Bundling The Solution Space Of Finite Constraint Satisfaction Problems, Berthe Y. Choueiry, Amy Beckwith Jan 2002

Techniques For Bundling The Solution Space Of Finite Constraint Satisfaction Problems, Berthe Y. Choueiry, Amy Beckwith

CSE Technical Reports

We study the backtrack-search procedure with forward checking (FCBT) for finding all solutions to a finite Constraint Satisfaction Problem (CSP). We describe how to use dynamic interchangeability to enhance the performance of search and represent the solution space in a compact manner. We evaluate this strategy (FC-DNPI) in terms of the numbers of nodes visited, constraints checked, and solution bundles generated by comparing it, theoretically and empirically, to other search strategies. We show that FC-DNPI is equivalent to search with the Cross Product Representation (FC-CPR) of [Hubbe and Freuder 1992] in terms of the numbers of solution bundles and constraint …


Two Algorithms For Shaped-Based Porosity Measures, Leen-Kiat Soh Jan 2002

Two Algorithms For Shaped-Based Porosity Measures, Leen-Kiat Soh

CSE Technical Reports

In this paper, we present two algorithms for shape-based porosity measures. Specifically, we describe two innovative attributes called perimeter porosity and area porosity as feature descriptors. Perimeter porosity refers to how “porous” or “weak” an image object is, while area porosity determines the degree of “branchiness” of an object. We show the applicability of the two measures through a SAR sea ice image classification example.


A Set Of New Sea Ice Feature Descriptors For Sar Images, Leen-Kiat Soh Jan 2002

A Set Of New Sea Ice Feature Descriptors For Sar Images, Leen-Kiat Soh

CSE Technical Reports

In this paper, we present a set of algorithms for describing sea ice features in SAR images. These algorithms we have implemented and incorporated in the ARKTOS software package, an intelligent sea ice classification. These algorithms have unique characteristics. Some are extensions or adaptations of existing image processing techniques to the specific problem domain of satellite sea ice classification, while some are innovative designs, inspired by the aforementioned problem domain. These feature descriptors may be generalized to other remote sensing applications.


Negotiation-Based Coalition Formation Model For Agents With Incomplete Information And Time Constraints, Leen-Kiat Soh Jan 2002

Negotiation-Based Coalition Formation Model For Agents With Incomplete Information And Time Constraints, Leen-Kiat Soh

CSE Technical Reports

In this paper we describe a coalition formation model for a cooperative multiagent system in which each agent has incomplete information about its dynamic and uncertain world and must respond to sensed events within time constraints. With incomplete information and uncertain world parameters while lacking time, an agent cannot afford organizing a rationally optimal coalition formation. Instead, our agents use a two-stage methodology. When an agent detects an event in the world, it first compiles a list of coalition candidates that it thinks would be useful, and then negotiates with the candidates. A negotiation is an exchange of information and …


Arktos: An Intelligent System For Satellite Sea Ice Image Analysis, Leen-Kiat Soh Jan 2002

Arktos: An Intelligent System For Satellite Sea Ice Image Analysis, Leen-Kiat Soh

CSE Technical Reports

We present an intelligent system for satellite sea ice image analysis named ARKTOS (Advanced Reasoning using Knowledge for Typing Of Sea ice). The underlying methodology of ARKTOS is to perform fully automated analysis of sea ice images by mimicking the reasoning process of sea ice experts and photo-interpreters. Hence, our approach is feature-based, rule-based classification supported by multisource data fusion and knowledge bases. A feature can be an ice floe, for example. ARKTOS computes a host of descriptors for that feature and then applies expert rules to classify the floe into one of several ice classes. ARKTOS also incorporates information …


The Latent Maximum Entropy Principle, Shaojun Wang, Ronald Rosenfeld, Yunxin Zhao, Dale Schuurmans Jan 2002

The Latent Maximum Entropy Principle, Shaojun Wang, Ronald Rosenfeld, Yunxin Zhao, Dale Schuurmans

Kno.e.sis Publications

We present an extension of Jaynes' maximum entropy principle to handle latent variables. We use an EM algorithm that incorporates nested iterative scaling to approximately calculate maximum entropy solutions for this principle, and give a proof of its convergence.