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1996

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Articles 1681 - 1710 of 2437

Full-Text Articles in Physical Sciences and Mathematics

A 240-Year Stable Oxygen And Carbon Isotopic Record In A Coral From South Florida: Implications For The Prediction Of Precipitation In Southern Florida, Peter Koenraad Swart, Richard E. Dodge, Harold J. Hudson Jan 1996

A 240-Year Stable Oxygen And Carbon Isotopic Record In A Coral From South Florida: Implications For The Prediction Of Precipitation In Southern Florida, Peter Koenraad Swart, Richard E. Dodge, Harold J. Hudson

Marine & Environmental Sciences Faculty Articles

This study reports on the δ18O and δ13C composition of the skeleton from a 240-year-old specimen of Montastraea faveolata growing in Biscayne National Park, South Florida. Annual variations in the δ18O of the skeleton deposited during the summer months show a bimodal correlation with summer rainfall. During wetter years, the δ18O of the coral skeleton and the amount of precipitation during the summer months are inversely correlated (r = -0. 7) reflecting dilution of the seawater by meteoric water lower in δ18O. During years in which summer rainfall is less …

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Ecology And Behavior Of Maxillipius Commensalis, A Gorgonophile Amphipod From Madang, Papua New Guinea (Crustacea: Amphipoda: Maxillipiidae), James Darwin Thomas Jan 1996

Ecology And Behavior Of Maxillipius Commensalis, A Gorgonophile Amphipod From Madang, Papua New Guinea (Crustacea: Amphipoda: Maxillipiidae), James Darwin Thomas

Marine & Environmental Sciences Faculty Articles

Maxillipius commensalis Lowry, is reported as an ectocommensal on arborescent gorgonaceans from coral reefs at Madang, Papua New Guinea. The family is reviewed and the male of this species is described. In-situ behavior studies show the amphipods to crowd close together in large numbers on one side of a gorgonian stalk. The terminal articles of the sixth pereopods are greatly elongated and whip-like and are waved at the sides in a circular motion, possibly facilitating spacing or feeding. When disturbed, the amphipods react en masse as a coherent group rather than as individuals.

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Organic Geochemistry And Petrology Of Oil Source Rocks, Carpathian Overthrust Region, Southeastern Poland — Implications For Petroleum Generation, Michael A. Kruge, Maria Mastalerz, Andrzej Solecki, B Artur Stankiewicz Jan 1996

Organic Geochemistry And Petrology Of Oil Source Rocks, Carpathian Overthrust Region, Southeastern Poland — Implications For Petroleum Generation, Michael A. Kruge, Maria Mastalerz, Andrzej Solecki, B Artur Stankiewicz

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The organic matter rich Oligocene Menilite black shales and mudstones are widely distributed in the Carpathian Overthrust region of southeastern Poland and have excellent hydrocarbon generation potential, according to TOC, Rock-Eval, and petrographic data. Extractable organic matter was characterized by an equable distribution of steranes by carbon number, by varying amounts of 28,30-dinor-hopane, 18α(H)-oleanane and by a distinctive group of C24 ring-A degraded triterpanes. The Menilite samples ranged in maturity from pre-generative to mid-oil window levels, with the most mature in the southeastern portion of the study area. Carpathian petroleum samples from Campanian-Oligocene sandstone reservoirs were similar …

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A Simple Model For Nonequilibrium Fluctuations In A Fluid, Alejandro Garcia, F. Baras, M. Malek Mansour Jan 1996

A Simple Model For Nonequilibrium Fluctuations In A Fluid, Alejandro Garcia, F. Baras, M. Malek Mansour

Alejandro Garcia

Presents a train model that shows the long-range spatial correlations of fluctuations in nonequilibrium fluid systems. Illustration of model through analysis of flat-car trains running on parallel tracks; Simulation of train model in computers; Theoretical analysis for fluctuations in the train model; Relationship between train model and the fluctuating hydrodynamic theory of fluids.

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A Computer-Based Editor For Lerdahl And Jackendoff's Rhythmic Structures, Bruno Degazio Jan 1996

A Computer-Based Editor For Lerdahl And Jackendoff's Rhythmic Structures, Bruno Degazio

Publications and Scholarship

In “A Generative Theory of Tonal Music”, Lerdahl and Jackendoff discuss two forms of rhythmic structure which they call metrical structure and grouping structure. Together these constitute a basis for an analytical understanding of rhythmic structure in music. This article is about a software based editor which allows the interactive exploration of these two types of hierarchical rhythmic structures.

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Circulant Weighing Designs, K. T. Arasu, Jennifer Seberry Jan 1996

Circulant Weighing Designs, K. T. Arasu, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Algebraic techniques are employed to obtain necessary conditions for the existence of certain families of circulant weighing designs. As an application we rule out the existence of many circulant weighing designs. In particular, we show that there does not exist a circulant weighing matrix of order 43 for any weight. We also prove two conjectures of Yosef Strassler. © 1996 John Wiley & Sons, Inc.

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Selective Withdrawal From Stratified Streams, Chia-Shun Yih, Song-Ping Zhu Jan 1996

Selective Withdrawal From Stratified Streams, Chia-Shun Yih, Song-Ping Zhu

Faculty of Informatics - Papers (Archive)

Selective withdrawal from a stratified stream is considered. The average density of the withdrawn fluid and the flow pattern are found, within the limitations on the densimetric Froude number and the withdrawal rate specified in this paper, to depend on the strength and location of the sink, and very little on any slight variation in the velocity distribution far upstream and the densimetric Froude number. The upstream density distribution is assumed linear, but many other density distributions can be similarly treated.

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Occurrence Of Selected Pesticides And Their Metabolites In Near-Surface Aquifers Of The Midwestern United States, Dana Kolpin, E. Michael Thurman, Donald Goolsby Jan 1996

Occurrence Of Selected Pesticides And Their Metabolites In Near-Surface Aquifers Of The Midwestern United States, Dana Kolpin, E. Michael Thurman, Donald Goolsby

United States Geological Survey: Staff Publications

The occurrence and distribution of selected pesticides and their metabolites were investigated through the collection of 837 water-quality samples from 303 wells across the Midwest. Results of this study showed that five of the six most frequently detected compounds were pesticide metabolites. Thus, it was common for a metabolite to be found more frequently in groundwater than its parent compound. The metabolite alachlor ethanesulfonic acid (alachlor- ESA; 2-[(2,6-diethylphenyl)(methoxymethyl)amino]-2- oxoethanesulfonic acid) was detected almost 10 times as frequently and at much higher concentrations than its parent compound alachlor (2-chloro-2',6'- diethyl-N-(methoxymethyl)acetamide). The median detectable atrazine (2-chloro-4-ethylamino-6- isopropylamino-s-triazine) concentration was almost half that …

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Egg Development In A High-Density Black Crappie (Pomoxis Nigromacuiatus) Population, Kevin L. Pope, Wade T. Geraets, David W. Willis Jan 1996

Egg Development In A High-Density Black Crappie (Pomoxis Nigromacuiatus) Population, Kevin L. Pope, Wade T. Geraets, David W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Female black crappie (Pomoxis nigromaculatus) were collected from Richmond Lake, South Dakota" and egg-diameter frequencies were examined to document spawning strategy during 1994. Two hundred and sixteen adult females [mean total length (TL) ±SE = 204 ± 1 mm] were collected and 85,572 egg diameters were measured. Female black crappie gonadosomatic-index (GSI) values exceeded 8% from 18 May to 22 June 1994, and the density of larval black crappie caught with an ichthyoplankton net peaked on 8 June 1994. The GSI values and larval catches indicated that the population, as a whole, had a single extended spawn from …

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Effects Of Red Imported Fire Ants On Northern Bobwhite Chicks, William M. Giuliano, Craig R. Allen, R. Scott Lutz, Stephen Demarais Jan 1996

Effects Of Red Imported Fire Ants On Northern Bobwhite Chicks, William M. Giuliano, Craig R. Allen, R. Scott Lutz, Stephen Demarais

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Populations of red imported fire ants (RIFA; Solenopsis invtcta) have spread rapidly throughout the southeastern United States. RIFA, directly or indirectly, negatively affect many wildlife species, and northern bobwhite (Colinus virginianus) appear to be particularly susceptible. We examined the effect of exposure to different numbers of RIFA for 15 and 60 seconds on body mass and survival of captive northern bobwhite chicks. Compared to unexposed birds, survival of chicks was reduced with exposure to as few as 50 RIFA for 60 seconds, or 200 RIFA for 15 seconds, and body mass was lower in chicks exposed to …

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Seasonal Influences On Freshwater Fisheries Sampling Data, Kevin L. Pope, David W. Willis Jan 1996

Seasonal Influences On Freshwater Fisheries Sampling Data, Kevin L. Pope, David W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Fisheries managers often assess fish populations using catch per unit effort (CPUE), size and age structure, growth, and condition. For many freshwater fishes and common sampling gears, CPUE, size and age structure, and condition are highest in the spring and fall, while growth commonly is fastest during the summer growing season. However, there are exceptions to these general trends, especially in populations with erratic recruitment, growth, or mortality. At the least, CPUE, size and age structure, growth, and condition of fish should be expected to change with season, given the effects of variable recruitment, growth, and mortality. However, if recruitment, …

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Upper Cretaceous Calcareous Nannofossil Biostratigraphy And Paleoceanography Of The Southern Ocean, David K. Watkins, Sherwood W. Wise Jr., James J. Popsichal, Jason Crux Jan 1996

Upper Cretaceous Calcareous Nannofossil Biostratigraphy And Paleoceanography Of The Southern Ocean, David K. Watkins, Sherwood W. Wise Jr., James J. Popsichal, Jason Crux

Department of Earth and Atmospheric Sciences: Faculty Publications

Nannofossil data from the Naturaliste Plateau (DSDP Legs 26 & 28), Falkland Plateau (DSDP Legs 36 & 71), Maud Rise (ODP Leg 113), Northeast Georgia Rise (ODP Leg 114), and Kerguelen Plateau (ODP Leg 120) yield a set of consistent, reliable biohorizons that form the basis of a revised calcareous nannofossil zonation for the Southern Ocean Upper Cretaceous. Analysis of this zonation indicates significant changes in the circum-Antarctic climatic regime during the Campanian and Maastrichtian that foreshadow the more dramatic climatic shifts of the Palaeogene. Calcareous nannofossils from the Turonian through the Lower Campanian of the studied sections are characterized …

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Temporal And Spatial Patterns In The Ross Sea: Phytoplankton Biomass, Elemental Composition, Productivity And Growth Rates, Walker O. Smith Jr., David Nelson, Giacomo R. Ditullio, Amy R. Leventer Jan 1996

Temporal And Spatial Patterns In The Ross Sea: Phytoplankton Biomass, Elemental Composition, Productivity And Growth Rates, Walker O. Smith Jr., David Nelson, Giacomo R. Ditullio, Amy R. Leventer

VIMS Articles

The temporal and spatial patterns of phytoplankton biomass, productivity, and particulate matter composition in the Ross Sea were assessed during cruises in January 1990 and February 1992. Biomass and primary productivity in the southern Ross Sea were greatest during mid-January, with surface chlorophyll concentrations, particulate organic carbon levels, and integrated primary productivity averaging 4.9 Ixg L 'l, 0.54 mg L-•, and 2.63 g C m"• d '•, respectively. Comparable mean concentrations and rates for February were 1.1 Ixg L 'l, 0.29 mg L 'l, and 0.78 g C m '•- d '• (decreases of 76, 46, and 70%, respectively), indicative …

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Gas Chromatographic Isolation Of Individual Compounds From Complex Matrices For Radiocarbon Dating, Ti Eglinton, Li Alueihare, Je Bauer, Erm Druffel, Ap Mcnichol Jan 1996

Gas Chromatographic Isolation Of Individual Compounds From Complex Matrices For Radiocarbon Dating, Ti Eglinton, Li Alueihare, Je Bauer, Erm Druffel, Ap Mcnichol

VIMS Articles

This paper describes the application of a novel, practical approach for isolation of individual compounds from complex organic matrices for natural abundance radiocarbon measurement. This is achieved through the use of automated preparative capillary gas chromatography (PCGC) to separate and recover sufficient quantities of individual target compounds for C-14 analysis by accelerator mass spectrometry (AMS). We developed and tested this approach using a suite of samples (plant lipids, petroleums) whose ages spanned the C-14 time scale and which contained a variety of compound types (fatty acids, sterols, hydrocarbons), Comparison of individual compound and bulk radiocarbon signatures for the isotopically homogeneous …

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Linking Sediment Transport And Stratigraphy On The Continental Shelf, Pl Wilberg, Da Cacchione, Rw Sternberg, L. Donelson Wright Jan 1996

Linking Sediment Transport And Stratigraphy On The Continental Shelf, Pl Wilberg, Da Cacchione, Rw Sternberg, L. Donelson Wright

VIMS Articles

The goal of the shelf sediment dynamics component of STRATAFORM is to link sediment transport processes active on the continental shelf to the formation and preservation of event beds in shelf sediment deposits. An approach combining shelf sediment-transport models with high-resolution measurements of water-column and bed properties over periods from several months to several years allows us to make quantitative estimates of bed modification caused by sediment resuspension during episodic transport events. These modifications include erosion and deposition of bed material, formation of graded storm beds, and changes in small-scale bed surface morphology. The characteristics of the resulting “event bed” …

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Mile-A-Minute Weed, (Polygonum Perfoliatum L.), An Invasive Vine In Natural And Disturbed Sites, J. Douglas Oliver Jan 1996

Mile-A-Minute Weed, (Polygonum Perfoliatum L.), An Invasive Vine In Natural And Disturbed Sites, J. Douglas Oliver

Faculty Publications and Presentations

Polygonum perfoliatum L. (Polygonaceae) or mile-a-minute weed, from eastern Asia, has been spreading through wild and disturbed areas of the mid-Atlantic United States. It has a wide ecological amplitude and is found on stream banks, moist thickets, roadsides, nurseries, wood-piles, clearings, and ditches. Polygonum perfoliatum presents serious problems for reforestation because it thrives where forests are clear-cut. A southward direction of spread indicates that the species will probably proliferate in at least some southern states. Mechanical control is not likely to be completely effective because seeds are often left behind. No appropriate biocontrols are known. The plant poses a threat …

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Leap Forward Virtual Clock: An O(Loglogn) Fair Queuing Scheme With Guaranteed Delays And Throughput Fairness, Subhash Suri, George Varghese, Girish P. Chandranmenon Jan 1996

Leap Forward Virtual Clock: An O(Loglogn) Fair Queuing Scheme With Guaranteed Delays And Throughput Fairness, Subhash Suri, George Varghese, Girish P. Chandranmenon

All Computer Science and Engineering Research

We describe an efficient fair queuing scheme, Leap Forward Virtual Clock, that provides end-to-end delay bounds almost identical to that of PGPS fair queuing, along with throughput fairness. Our scheme can be implemented with a worst-case time O(loglogN) per packet guaranteed delay and throughput fairness. As its name suggests, our scheme is based on Zhang's virtual clock. While the original virtual clock scheme does not achieve throughput fairness, we can modify it with a simple leap forward mechanism that keeps the server clock from lagging too far behind the packet tags. We prove that our scheme guarantees a fair share …

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Vaudeville: A High Performance, Voice-Activated Teleconferencing Application, Jyoti K. Parwatikar, T. Paul Mccartney, John D. Dehart, Maynard Engebretson, Kenneth J. Goldman Jan 1996

Vaudeville: A High Performance, Voice-Activated Teleconferencing Application, Jyoti K. Parwatikar, T. Paul Mccartney, John D. Dehart, Maynard Engebretson, Kenneth J. Goldman

All Computer Science and Engineering Research

We present a voice-activated, hands-off, ATM-based video conferencing application. The application, called Vaudeville, features high quality NTSC video, voice-activated audio transmission, audio bridging of two audio streams, and voice-activated video switching. It supports multiple simultaneous multi-party conferences using a scalable multicast mechanism. We describe how Vaudeville was built using a component-based distributed programming environment. We also describe the algorithms used to contorl the audio and video of the applciation. Audio and video are encoded in hardware using an ATM hardware multimedia interface.

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Design And Implementation Of A Practical Security-Conscious Electronic Polling System, Lorrie Faith Cranor, Ron K. Cytron Jan 1996

Design And Implementation Of A Practical Security-Conscious Electronic Polling System, Lorrie Faith Cranor, Ron K. Cytron

All Computer Science and Engineering Research

We present the design and implementation of Sensus, a practical, secure and private system for conducting surveys and elections over computer networks. Expanding on the work of Fujioka, Okamoto, and Ohta, Sensus uses blind signatures to ensure that only registered voters can vote and that each registered voter only votes once, while at the same time maintaining voters' privacy. Sensus allows voters to verify independently that their votes were counted correctly, and anonymously challenge the results should their votes be miscounted. We outline seven desirable properties of voting systems and show that Sensus satisfied these properties well, in some cases …

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Bringing Real-Time Scheduling Theory And Practice Closer For Multimedia Computing, R. Gopalakrishnan, Guru M. Parulkar Jan 1996

Bringing Real-Time Scheduling Theory And Practice Closer For Multimedia Computing, R. Gopalakrishnan, Guru M. Parulkar

All Computer Science and Engineering Research

This paper seeks to bridge the gap between theory and practice of real-time scheduling in the domain of multimedia computer systems. We show that scheduling algorithms that are good in theory, often have practical limitations. However when these algorithms are modified based on practical considerations, existing theoretical results cannot be used as they are. In this paper we motivate the need for new scheduling schemes for multimedia protocol processing, and demonstrate their real-time performance in our prototype implementation. We then explain the observed results by analysis and measurement. More specifically, we show that using strict preemption can introduce overheads in …

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Distributed Stream Filtering For Database Applications, William M. Shapiro, Kenneth J. Goldman Jan 1996

Distributed Stream Filtering For Database Applications, William M. Shapiro, Kenneth J. Goldman

All Computer Science and Engineering Research

Distributed stream filtering is a mechanism for implementing a new class of real-time applications with distributed processing requirements. These applications require scalable architectures to support the efficient processing and multiplexing of large volumes of continuously generated data. This paper provides an overview of a stream-oriented model for database query processing and presents a supporting implementation. To facilitate distributed stream filtering, we introduce several new query processing operations, including pipelined filtering that efficiently joins and eliminates duplicates from database streams and a new join method, the progressive join, that joins streams of tuples. Finally, recognizing that the stream-oriented model results in …

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An Algorithm For Message Delivery To Mobile Units, Amy L. Murphy, Gruia-Catalin Roman, George Varghese Jan 1996

An Algorithm For Message Delivery To Mobile Units, Amy L. Murphy, Gruia-Catalin Roman, George Varghese

All Computer Science and Engineering Research

With recent advances in wireless communication and the ubiquity of laptops, mobile computing has become an important research area. An essential problem in mobile computing is the delivery of a message from a source to either a single mobile node, unicast, or to a group of mobile nodes, multicast. Standard solutions used in Mobile IP and cellular phones for the unicast problem rely on tracking the mobile unit. Tracking solutions scale badly when mobile nodes move frequently, and do not generalize well to multicast delivery. Our paper proposes a new message delivery algorithm for micromobility based on a modification of …

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Mobile Unity Coordination Constructs Applied To Packet Forwarding For Mobile Hosts, Peter J. Mccann, Gruia-Catalin Roman Jan 1996

Mobile Unity Coordination Constructs Applied To Packet Forwarding For Mobile Hosts, Peter J. Mccann, Gruia-Catalin Roman

All Computer Science and Engineering Research

With recent advances in wireless communication technology, mobile computing is an increasingly important area of research. A mobile system is one where independently executing components may migrate through some space during the course of the computation, and where the pattern of connectivity among the components changes as they move in and out of proximity. Mobile UNITY is a language and logic for specifying and reasoning about mobile systems, the components of which must operate in a highly decoupled way. In this paper it is argued that Mobile UNITY contributes to the modular development of system specifications because of the declarative …

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A Usability Study Of End-User Construction Of Direct Manipulation User Interfaces, T Paul Mccartney Jan 1996

A Usability Study Of End-User Construction Of Direct Manipulation User Interfaces, T Paul Mccartney

All Computer Science and Engineering Research

This paper describes an empirical study of end-users that tested the usability of The Programmers' Playground graphical environment. The Programmers' Playground is a software library and run-time system for constructing distributed multimedia applications. Playground's graphical environment enables end-users to create direct manipulation graphical user interfaces (GUIs) and to dynamically configure communication among distributed application components. In this study, 28 end-users with no prior experience in distributed computing or user interface construction were timed and evaluated on several tasks using our graphical environment. Tasks included the use of direct and indirect constraint relationships, visual configuration of distributed applications, and graphical user …

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Sources Of Epidemiological Equivocacy, Timothy Sly Jan 1996

Sources Of Epidemiological Equivocacy, Timothy Sly

RISK: Health, Safety & Environment (1990-2002)

Mr. Sly discusses five sources of uncertainty and ambiguity in health and medical research that can interfere with decision making.

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Environmental Racism And Biased Methods Of Risk Assessment, Daniel C. Wigley, Kristin S. Shrader-Frechette Jan 1996

Environmental Racism And Biased Methods Of Risk Assessment, Daniel C. Wigley, Kristin S. Shrader-Frechette

RISK: Health, Safety & Environment (1990-2002)

Based on analysis of a risk assessment for a proposed Louisiana uranium enrichment facility, the authors argue that environmental injustice occurs when assessors' scientific methods cause de facto discrimination.

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An Assessment Of Burbot (Lota Iota) Weight - Length Data From North American Populations, Shannon J. Fisher, David W. Willis, Kevin L. Pope Jan 1996

An Assessment Of Burbot (Lota Iota) Weight - Length Data From North American Populations, Shannon J. Fisher, David W. Willis, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Declining buroot (Lola lola) abundance across some portions of North America has prompted a search for additional evaluation tools, including a measure of condition. Weight - length data were compiled for 10293 burbot from 79 North American populations. These data were used to develop a 75th percentile standard weight (W,) equation using the regression-line-percentile technique. The proposed equation is log10 W3 = - 4.868 + 2.898 log10 TL, where Ws is the standard weight in grams, and TL is the maximum total length in millimetres. The equation is valid for burbot ≥20 cm and …

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On A Conjecture Of S. Reich, Peter Z. Daffer, Hideaki Kaneko, Wu Li Jan 1996

On A Conjecture Of S. Reich, Peter Z. Daffer, Hideaki Kaneko, Wu Li

Mathematics & Statistics Faculty Publications

Simeon Reich (1974) proved that the fixed point theorem for single-valued mappings proved by Boyd and Wong can be generalized to multivalued mappings which map points into compact sets. He then asked (1983) whether his theorem can be extended to multivalued mappings whose range consists of bounded closed sets. In this note, we provide an affirmative answer for a certain subclass of Boyd-Wong contractive mappings.

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Doubly Differential Final-State Momentum Distributions Of The Ionization Products In Collision Of Bare Ions With Hydrogen, Lokesh C. Tribedi, P. Richard, Y. D. Wang, C. D. Lin, Ronald E. Olson Jan 1996

Doubly Differential Final-State Momentum Distributions Of The Ionization Products In Collision Of Bare Ions With Hydrogen, Lokesh C. Tribedi, P. Richard, Y. D. Wang, C. D. Lin, Ronald E. Olson

Physics Faculty Research & Creative Works

In this paper recoil-ion production cross sections are presented differential in recoil-ion longitudinal momentum and electron emission angle in ionization of atomic and molecular hydrogen by bare ion projectiles. A new formulation for constructing these double differential distributions from the measured electron double differential cross sections is used. A novel feature is the separation of two different branches of the recoil-ion longitudinal momentum distribution corresponding to soft and hard collision mechanisms of ionization. The single differential distributions have also been derived. © 1996 The American Physical Society.

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Imaging Of Saddle Point Electron Emission In Slow, R. Dörner, H. Khemliche, M. H. Prior, C. L. Cocke, J. A. Gary, Ronald E. Olson, V. Mergel, J. Ullrich, H. Schmidt-Böcking Jan 1996

Imaging Of Saddle Point Electron Emission In Slow, R. Dörner, H. Khemliche, M. H. Prior, C. L. Cocke, J. A. Gary, Ronald E. Olson, V. Mergel, J. Ullrich, H. Schmidt-Böcking

Physics Faculty Research & Creative Works

The two-dimensional velocity distribution of electrons emitted in 5-15 keV p - He collisions has been measured for completely determined motion of the nuclei, that is, as a function of the impact parameter and in a well defined scattering plane. The electrons are emitted preferentially in the scattering plane and in the forward direction. The velocity distributions show sharp structures that vary strongly with impact parameter and projectile velocity. The results are compared to classical trajectory calculations. © 1996 The American Physical Society.

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