Showing papers by "University of Nebraska–Lincoln published in 1996"

The use of the Normalized Difference Water Index (NDWI) in the delineation of open water features

Abstract: The Normalized Difference Water Index (NDWI) is a new method that has been developed to delineate open water features and enhance their presence in remotely-sensed digital imagery. The NDWI makes use of reflected near-infrared radiation and visible green light to enhance the presence of such features while eliminating the presence of soil and terrestrial vegetation features. It is suggested that the NDWI may also provide researchers with turbidity estimations of water bodies using remotely-sensed digital data.

Introduction to data compression

Abstract: Preface 1 Introduction 1.1 Compression Techniques 1.1.1 Lossless Compression 1.1.2 Lossy Compression 1.1.3 Measures of Performance 1.2 Modeling and Coding 1.3 Organization of This Book 1.4 Summary 1.5 Projects and Problems 2 Mathematical Preliminaries 2.1 Overview 2.2 A Brief Introduction to Information Theory 2.3 Models 2.3.1 Physical Models 2.3.2 Probability Models 2.3.3. Markov Models 2.3.4 Summary 2.5 Projects and Problems 3 Huffman Coding 3.1 Overview 3.2 "Good" Codes 3.3. The Huffman Coding Algorithm 3.3.1 Minimum Variance Huffman Codes 3.3.2 Length of Huffman Codes 3.3.3 Extended Huffman Codes 3.4 Nonbinary Huffman Codes 3.5 Adaptive Huffman Coding 3.5.1 Update Procedure 3.5.2 Encoding Procedure 3.5.3 Decoding Procedure 3.6 Applications of Huffman Coding 3.6.1 Lossless Image Compression 3.6.2 Text Compression 3.6.3 Audio Compression 3.7 Summary 3.8 Projects and Problems 4 Arithmetic Coding 4.1 Overview 4.2 Introduction 4.3 Coding a Sequence 4.3.1 Generating a Tag 4.3.2 Deciphering the Tag 4.4 Generating a Binary Code 4.4.1 Uniqueness and Efficiency of the Arithmetic Code 4.4.2 Algorithm Implementation 4.4.3 Integer Implementation 4.5 Comparison of Huffman and Arithmetic Coding 4.6 Applications 4.6.1 Bi-Level Image Compression-The JBIG Standard 4.6.2 Image Compression 4.7 Summary 4.8 Projects and Problems 5 Dictionary Techniques 5.1 Overview 5.2 Introduction 5.3 Static Dictionary 5.3.1 Diagram Coding 5.4 Adaptive Dictionary 5.4.1 The LZ77 Approach 5.4.2 The LZ78 Approach 5.5 Applications 5.5.1 File Compression-UNIX COMPRESS 5.5.2 Image Compression-the Graphics Interchange Format (GIF) 5.5.3 Compression over Modems-V.42 bis 5.6 Summary 5.7 Projects and Problems 6 Lossless Image Compression 6.1 Overview 6.2 Introduction 6.3 Facsimile Encoding 6.3.1 Run-Length Coding 6.3.2 CCITT Group 3 and 4-Recommendations T.4 and T.6 6.3.3 Comparison of MH, MR, MMR, and JBIG 6.4 Progressive Image Transmission 6.5 Other Image Compression Approaches 6.5.1 Linear Prediction Models 6.5.2 Context Models 6.5.3 Multiresolution Models 6.5.4 Modeling Prediction Errors 6.6 Summary 6.7 Projects and Problems 7 Mathematical Preliminaries 7.1 Overview 7.2 Introduction 7.3 Distortion Criteria 7.3.1 The Human Visual System 7.3.2 Auditory Perception 7.4 Information Theory Revisted 7.4.1 Conditional Entropy 7.4.2 Average Mutual Information 7.4.3 Differential Entropy 7.5 Rate Distortion Theory 7.6 Models 7.6.1 Probability Models 7.6.2 Linear System Models 7.6.3 Physical Models 7.7 Summary 7.8 Projects and Problems 8 Scalar Quantization 8.1 Overview 8.2 Introduction 8.3 The Quantization Problem 8.4 Uniform Quantizer 8.5 Adaptive Quantization 8.5.1 Forward Adaptive Quantization 8.5.2 Backward Adaptive Quantization 8.6 Nonuniform Quantization 8.6.1 pdf-Optimized Quantization 8.6.2 Companded Quantization 8.7 Entropy-Coded Quantization 8.7.1 Entropy Coding of Lloyd-Max Quantizer Outputs 8.7.2 Entropy-Constrained Quantization 8.7.3 High-Rate Optimum Quantization 8.8 Summary 8.9 Projects and Problems 9 Vector Quantization 9.1 Overview 9.2 Introduction 9.3 Advantages of Vector Quantization over Scalar Quantization 9.4 The Linde-Buzo-Gray Algorithm 9.4.1 Initializing the LBG Algorithm 9.4.2 The Empty Cell Problem 9.4.3 Use of LBG for Image Compression 9.5 Tree-Structured Vector Quantizers 9.5.1 Design of Tree-Structured Vector Quantizers 9.6 Structured Vector Quantizers 9.6.1 Pyramid Vector Quantization 9.6.2 Polar and Spherical Vector Quantizers 9.6.3 Lattice Vector Quantizers 9.7 Variations on the Theme 9.7.1 Gain-Shape Vector Quantization 9.7.2 Mean-Removed Vector Quantization 9.7.3 Classified Vector Quantization 9.7.4 Multistage Vector Quantization 9.7.5 Adaptive Vector Quantization 9.8 Summary 9.9 Projects and Problems 10 Differential Encoding 10.1 Overview 10.2 Introduction 10.3 The Basic Algorithm 10.4 Prediction in DPCM 10.5 Adaptive DPCM (ADPCM) 10.5.1 Adaptive Quantization in DPCM 10.5.2 Adaptive Prediction in DPCM 10.6 Delta Modulation 10.6.1 Constant Factor Adaptive Delta Modulation (CFDM) 10.6.2 Continuously Variable Slope Delta Modulation 10.7 Speech Coding 10.7.1 G.726 10.8 Summary 10.9 Projects and Problems 11 Subband Coding 11.1 Overview 11.2 Introduction 11.3 The Frequency Domain and Filtering 11.3.1 Filters 11.4 The Basic Subband Coding Algorithm 11.4.1 Bit Allocation 11.5 Application to Speech Coding-G.722 11.6 Application to Audio Coding-MPEG Audio 11.7 Application to Image Compression 11.7.1 Decomposing an Image 11.7.2 Coding the Subbands 11.8 Wavelets 11.8.1 Families of Wavelets 11.8.2 Wavelets and Image Compression 11.9 Summary 11.10 Projects and Problems 12 Transform Coding 12.1 Overview 12.2 Introduction 12.3 The Transform 12.4 Transforms of Interest 12.4.1 Karhunen-Loeve Transform 12.4.2 Discrete Cosine Transform 12.4.3 Discrete Sine Transform 12.4.4 Discrete Walsh-Hadamard Transform 12.5 Quantization and Coding of Transform Coefficients 12.6 Application to Image Compression-JPEG 12.6.1 The Transform 12.6.2 Quantization 12.6.3 Coding 12.7 Application to Audio Compression 12.8 Summary 12.9 Projects and Problems 13 Analysis/Synthesis Schemes 13.1 Overview 13.2 Introduction 13.3 Speech Compression 13.3.1 The Channel Vocoder 13.3.2 The Linear Predictive Coder (Gov.Std.LPC-10) 13.3.3 Code Excited Linear Prediction (CELP) 13.3.4 Sinusoidal Coders 13.4 Image Compression 13.4.1 Fractal Compression 13.5 Summary 13.6 Projects and Problems 14 Video Compression 14.1 Overview 14.2 Introduction 14.3 Motion Compensation 14.4 Video Signal Representation 14.5 Algorithms for Videoconferencing and Videophones 14.5.1 ITU_T Recommendation H.261 14.5.2 Model-Based Coding 14.6 Asymmetric Applications 14.6.1 The MPEG Video Standard 14.7 Packet Video 14.7.1 ATM Networks 14.7.2 Compression Issues in ATM Networks 14.7.3 Compression Algorithms for Packet Video 14.8 Summary 14.9 Projects and Problems A Probability and Random Processes A.1 Probability A.2 Random Variables A.3 Distribution Functions A.4 Expectation A.5 Types of Distribution A.6 Stochastic Process A.7 Projects and Problems B A Brief Review of Matrix Concepts B.1 A Matrix B.2 Matrix Operations C Codes for Facsimile Encoding D The Root Lattices Bibliography Index

Magnetic Properties of Nanostructured Materials

Abstract: Understanding the correlation between magnetic properties and nanostructure involves collaborative efforts between chemists, physicists, and materials scientists to study both fundamental properties and potential applications. This article introduces a classification of nanostructure morphology according to the mechanism responsible for the magnetic properties. The fundamental magnetic properties of interest and the theoretical frameworks developed to model these properties are summarized. Common chemical and physical techniques for the fabrication of magnetic nanostructures are surveyed, followed by some examples of recent investigations of magnetic systems with structure on the nanometer scale. The article concludes with a brief discussion of some promising experimental techniques in synthesis and measurements.

The modifiable areal unit problem and implications for landscape ecology

Abstract: Landscape ecologists often deal with aggregated data and multiscaled spatial phenomena. Recognizing the sensitivity of the results of spatial analyses to the definition of units for which data are collected is critical to characterizing landscapes with minimal bias and avoidance of spurious relationships. We introduce and examine the effect of data aggregation on analysis of landscape structure as exemplified through what has become known, in the statistical and geographical literature, as the Modifiable Areal Unit Problem (MAUP). The MAUP applies to two separate, but interrelated, problems with spatial data analysis. The first is the “scale problem”, where the same set of areal data is aggregated into several sets of larger areal units, with each combination leading to different data values and inferences. The second aspect of the MAUP is the “zoning problem”, where a given set of areal units is recombined into zones that are of the same size but located differently, again resulting in variation in data values and, consequently, different conclusions. We conduct a series of spatial autocorrelation analyses based on NDVI (Normalized Difference Vegetation Index) to demonstrate how the MAUP may affect the results of landscape analysis. We conclude with a discussion of the broaderscale implications for the MAUP in landscape ecology and suggest approaches for dealing with this issue.

PHOSPHOENOLPYRUVATE CARBOXYLASE: A Ubiquitous, Highly Regulated Enzyme in Plants.

Abstract: ▪ Abstract Since plant phosphoenolpyruvate carboxylase (PEPC) was last reviewed in the Annual Review of Plant Physiology over a decade ago (O'Leary 1982), significant advances have been made in our knowledge of this oligomeric, cytosolic enzyme. This review highlights this exciting progress in plant PEPC research by focusing on the three major areas of recent investigation: the enzymology of the protein; its posttranslational regulation by reversible protein phosphorylation and opposing metabolite effectors; and the structure, expression, and molecular evolution of the nuclear PEPC genes. It is hoped that the next ten years will be equally enlightening, especially with respect to the three-dimensional structure of the plant enzyme, the molecular analysis of its highly regulated protein-Ser/Thr kinase, and the elucidation of its associated signal-transduction pathways in various plant cell types.

Visual Cryptography for General Access Structures

Abstract: A visual cryptography scheme for a set P ofnparticipants is a method of encoding a secret imageSIintonshadow images called shares, where each participant in P receives one share. Certain qualified subsets of participants can “visually” recover the secret image, but other, forbidden, sets of participants have no information (in an information-theoretic sense) onSI. A “visual” recovery for a setX?P consists of xeroxing the shares given to the participants inXonto transparencies, and then stacking them. The participants in a qualified setXwill be able to see the secret image without any knowledge of cryptography and without performing any cryptographic computation. In this paper we propose two techniques for constructing visual cryptography schemes for general access structures. We analyze the structure of visual cryptography schemes and we prove bounds on the size of the shares distributed to the participants in the scheme. We provide a novel technique for realizingkout ofnthreshold visual cryptography schemes. Our construction forkout ofnvisual cryptography schemes is better with respect to pixel expansion than the one proposed by M. Naor and A. Shamir (Visual cryptography,in“Advances in Cryptology?Eurocrypt '94” CA. De Santis, Ed.), Lecture Notes in Computer Science, Vol. 950, pp. 1?12, Springer-Verlag, Berlin, 1995) and for the case of 2 out ofnis the best possible. Finally, we consider graph-based access structures, i.e., access structures in which any qualified set of participants contains at least an edge of a given graph whose vertices represent the participants of the scheme.

Identification of a Brazil-nut allergen in transgenic soybeans

Abstract: Background The nutritional quality of soybeans (Glycine max) is compromised by a relative deficiency of methionine in the protein fraction of the seeds. To improve the nutritional quality, methionine-rich 2S albumin from the Brazil nut (Bertholletia excelsa) has been introduced into transgenic soybeans. Since the Brazil nut is a known allergenic food, we assessed the allergenicity of the 2S albumin. Methods The ability of proteins in transgenic and nontransgenic soybeans, Brazil nuts, and purified 2S albumin to bind to IgE in serum from subjects allergic to Brazil nuts was determined by radioallergosorbent tests (four subjects) and sodium dodecyl sulfate–polyacrylamide-gel electrophoresis (nine subjects) with immunoblotting and autoradiography. Three subjects also underwent skin-prick testing with extracts of soybean, transgenic soybean, and Brazil nut. Results On radioallergosorbent testing of pooled serum from four subjects allergic to Brazil nuts, protein extracts of transgenic soybean inhibited bindin...

Auditory Neurophysiologic Responses and Discrimination Deficits in Children with Learning Problems

Abstract: Children with learning problems often cannot discriminate rapid acoustic changes that occur in speech. In this study of normal children and children with learning problems, impaired behavioral discrimination of a rapid speech change (/dalpha/versus/galpha/) was correlated with diminished magnitude of an electrophysiologic measure that is not dependent on attention or a voluntary response. The ability of children with learning problems to discriminate another rapid speech change (/balpha/versus/walpha/) also was reflected in the neurophysiology. These results indicate that some children's discrimination deficits originate in the auditory pathway before conscious perception and have implications for differential diagnosis and targeted therapeutic strategies for children with learning disabilities and attention disorders.

New model for electron-impact ionization cross sections of molecules

Abstract: A theoretical model for electron‐impact ionization cross sections, which has been developed primarily for atoms and atomic ions, is applied to neutral molecules. The new model combines the binary‐encounter theory and the Bethe theory for electron‐impact ionization, and uses minimal theoretical data for the ground state of the target molecule, which are readily available from public‐domain molecular structure codes such as GAMESS. The theory is called the binary‐encounter Bethe (BEB) model, and does not, in principle, involve any adjustable parameters. Applications to 19 molecules, including H2, NO, CH2, C6H6, and SF6, are presented, demonstrating that the BEB model provides total ionization cross sections by electron impact from threshold to several keV with an average accuracy of 15% or better at the cross section peak, except for SiF3. The BEB model can be applied to stable molecules as well as to transient radicals.

Identification and High-Density Mapping of Gene-Rich Regions in Chromosome Group 1 of Wheat

Abstract: We studied the distribution of genes and recombination in wheat (Triticum aestivum) group 1 chromosomes by comparing high-density physical and genetic maps. Physical maps of chromosomes 1A, 1B, and 1D were generated by mapping 50 DNA markers on 56 single-break deletion lines. A consensus physical map was compared with the 1D genetic map of Triticum tauschii (68 markers) and a Triticeae group 1 consensus map (288 markers) to generate a cytogenetic ladder map (CLM). Most group 1 markers (86%) were present in five clusters that encompassed only 10% of the group 1 chromosome. This distribution may reflect that of genes because more than half of the probes were cDNA clones and 30% were PstI genomic. All 14 agronomically important genes in group 1 chromosomes were present in these clusters. Most recombination occurred in gene-cluster regions. Markers fell at an average distance of 244 kb in these regions. The CLM involving the Triticeae consensus genetic map revealed that the above distribution of genes and recombination is the same in other Triticeae species. Because of a significant number of common markers, our CLM can be used for comparative mapping and to estimate physical distances among markers in many Poaceae species including rice and maize.

Genome Duplication in Soybean ( Glycine subgenus soja )

Abstract: Restriction fragment length polymorphism mapping data from nine populations (Glycine max X G. soja and G. max X G. max) of the Glycine subgenus soja genome led to the identification of many duplicated segments of the genome. Linkage groups contained up to 33 markers that were duplicated on other linkage groups. The size of homoeologous regions ranged from 1.5 to 106.4 cM, with an average size of 45.3 cM. We observed segments in the soybean genome that were present in as many as six copies with an average of 2.55 duplications per segment. The presence of nested duplications suggests that at least one of the original genomes may have undergone an additional round of tetraploidization. Tetraploidization, along with large internal duplications, accounts for the highly duplicated nature of the genome of the subgenus. Quantitative trait loci for seed protein and oil showed correspondence across homoeologous regions, suggesting that the genes or gene families contributing to seed composition have retained similar functions throughout the evolution of the chromosomes.

Push−Pull Arylethynyl Porphyrins: New Chromophores That Exhibit Large Molecular First-Order Hyperpolarizabilities

Abstract: A new class of chromophores has been fabricated that features both electron-releasing and electron-withdrawing groups fused via an intervening ethynyl moiety to the carbon framework of a (porphinato)metal complex. These species possess large molecular first-order hyperpolarizabilities (β). We report herein the synthesis, optical spectroscopy, and the hyper-Rayleigh scattering data used to determine the β values of two archetypal members of this new class of exceptional nonlinear chromophores: [5-[[4‘-(dimethylamino)phenyl]ethynyl]-15-[(4‘‘-nitrophenyl)ethynyl]-10,20-diphenylporphinato]copper(II) and [5-[[4‘-(dimethylamino)phenyl]ethynyl]-15-[(4‘‘-nitrophenyl)ethynyl]-10,20-diphenylporphinato]zinc(II). One of these compounds, [5-[[4‘-(dimethylamino)phenyl]ethynyl]-15-[(4‘‘-nitrophenyl)ethynyl]-10,20-diphenylporphinato]zinc(II), possesses β values near 5000 × 10-30 esu at incident irradiation wavelengths of both 830 and 1064 nm. These studies suggest that this chromophoric structural motif may find utility...

The double-edged sword: Emotional regulation for children at risk

Abstract: The capacity to manage emotion is based on the growth of self-regulatory capacities in the early years, but is also affected by situational demands, influences from other people, and the child's goals for regulating emotion in a particular setting. For most children growing up in supportive contexts, the growth of emotional regulation is associated with enhanced psychosocial well-being and socioemotional competence. But for children who are at risk for the development of psychopathology owing to environmental stresses or intrinsic vulnerability (or their interaction), emotional regulation often entails inherent trade-offs that make nonoptimal strategics of managing emotion expectable, perhaps inevitable, in a context of difficult environmental demands and conflicting emotional goals. This analysis discusses how emotional regulation in children at risk may simultaneously foster both resiliency and vulnerability by considering how emotion is managed when children (a) are living with a parent who is depressed, (b) witness or experience domestic violence, or (c) are temperamentally inhibited when encountering novel challenges. In each case, the child's efforts to manage emotion may simultaneously buffer against certain stresses while also enhancing the child's vulnerability to other risks and demands. This double-edged sword of emotional regulation in conditions of risk for children cautions against using “optimal” emotional regulation as an evaluative standard for such children or assuming that emotional regulation necessarily improves psychosocial well-being. It also suggests how the study of emotional regulation must consider the goals for regulating emotion and the contexts in which those goals are sought.

Mechanical and Barrier Properties of Egg Albumen Films

Abstract: Films were cast and dried from heated, alkaline aqueous egg albumen solutions containing glycerin (GLY) at 30, 40, or 50% w/w of protein, polyethylene glycol (PEG) at 50 or 60%, or sorbitol (S) at 50 or 60% as plasticizers. PEG-plasticized (60%) films also were prepared by substituting 10, 30, 50, or 70% of albumen with yolk solids. Film tensile strength (TS), elongation at break (E), water vapor permeability (WVP), and Hunter color values were measured. At a plasticizer content of 50%, films with S had the lowest WVP while films with PEG had the greatest E. S- and PEG-plasticized films had greater TS than GLY-plasticized films. Yolk solids decreased film TS, E, and WVP while increasing film yellowness.

Nickel-Containing Carbon Monoxide Dehydrogenase/Acetyl-CoA Synthase†,‡

Abstract: This article reviews an enzyme with two important catalytic activities, carbon monoxide dehydrogenase (CODH) (reaction 1) and acetyl-CoA synthase (ACS) (reaction 2). These reactions are key to an autotrophic pathway that has become known as the reductive acetyl-CoA or the Wood/Ljungdahl pathway. ACS also catalyzes two exchange reactions that have been valuable in elucidating the mechanism of acetyl-CoA synthesis: an exchange reaction between CO and the carbonyl group of acetyl-CoA (reaction 3) and an exchange reaction between free CoA and the CoA moiety of acetyl-CoA (reaction 4). Ten years ago, one of the authors (Ragsdale) and Harland Wood, first proposed that the CODH from acetogenic bacteria catalyzes the final steps in acetyl-CoA synthesis and, therefore, should be renamed acetyl-CoA synthase. It was previously accepted that these steps occurred on a cobalt-containing corrinoid protein. This was a controversial proposal that required the existence of carbonyl, methyl, and acetyl enzyme adducts. Proof of this postulate was nontrivial since it required the characterization of enzyme-bound intermediates. With the goal of detecting and characterizing intermediates in the pathway, the authors` laboratory and others began to probe the enzyme in the resting state and at different stages of the catalytic cycle with sensitive spectroscopic methods.more » This review summarizes the fruits of the combined labor of the laboratories working on this interesting problem. 237 refs.« less

Characterization of biological types of cattle (Cycle IV): carcass traits and longissimus palatability.

Abstract: Carcass (n = 854) and longissimus thoracis palatability (n = 802) traits from F 1 steers obtained from mating Hereford, Angus, and MARC III cows to Hereford or Angus (HA), Tuli (Tu), Boran (Bo), Brahman (Br), Piedmontese (Pm), or Belgian Blue (BB) sires were compared. Data were adjusted to constant age (444 d), carcass weight (333 kg), fat thickness (1.0 cm), fat trim percentage (21%), and marbling (Small 00 ) end points. Results presented in this abstract are for age-constant data. Carcasses from BB- and HA-sired steers were heaviest (P < 0.05) and carcasses from Bo- and Tu-sired steers were lightest (P < 0.05). Adjusted fat thickness was greatest (P < 0.05) on carcasses from HA-sired steers and least (P < 0.05) on carcasses from BB-and Pm-sired steers. Numerical USDA yield grades were lowest (P < 0.05) for carcasses from Pm- and BB-sired steers and highest (P < 0.05) for carcasses from HA- and Br-sired steers. Marbling scores were highest (P < 0.05) for carcasses from HA- and Tu-sired steers and lowest (P < 0.05) for carcasses from Br-, BB-, and Pm-sired steers. Longissimus thoracis from carcasses of HA-, Pm-, and Tu-sired steers had the lowest (P < 0.05) 14-d postmortem Warner-Bratzler shear force values. Carcasses from HA-sired steers had longissimus thoracis with the highest (P < 0.05) tenderness ratings at 7 d postmortem. Longissimus thoracis from carcasses of Br- and Bo-sired steers had the highest (P < 0.05) Warner-Bratzler shear forces and the lowest (P < 0.05) tenderness ratings at 7 d postmortem. Adjustment of traits to various slaughter end points resulted in some changes in sire breed differences for carcass traits but had little effect on palatability traits. Carcasses from BB- and Pm-sired steers provided the most desirable combination of yield grade and longissimus palatability, but carcasses from HA-cross steers provided the most desirable combination of quality grade and longissimus palatability. Tuli, a breed shown to be heat-tolerant, had longissimus tenderness similar to that of the non-heat-tolerant breeds and more tender longissimus than the heat-tolerant breeds in this study.

Nitrogen Deficiency Detection Using Reflected Shortwave Radiation from Irrigated Corn Canopies

Abstract: Techniques that measure the N status of corn (Zea mays L.) can aid in management decisions that have economic and environmental implications. This study was conducted to identify reflected electromagnetic wavelengths most sensitive to detecting N deficiencies in a corn canopy with the possibility for use as a management tool. Reflected shortwave radiation was measured from an irrigated corn N response trial with four hybrids and five N rates at 0, 40, 80, 120, and 160 kg N ha -1 in 1992 and 0, 50, 100, 150, and 200 kg N ha -1 in 1993. A portable spectroradiometer was used to measure reflected radiation (400-1100 nm in 1992, 350-1050 nm in 1993) from corn canopies at approximately the R5 growth stage. Regression analyses revealed that reflected radiation near 550 and 710 nm was superior to reflected radiation near 450 or 650 nm for detecting N deficiencies. The ratio of light reflectance between 550 and 600 nm to light reflectance between 800 and 900 nm also provided sensitive detection of N stress. In 1993, an inexpensive photometric cell, which has peak sensitivity to light centered at 550 nm, was also used to measure reflected radiation from a corn canopy. Photometric cell readings correlated with relative grain yield (P < 0.001, r 2 = 0.74), but more research will be required to develop procedures to account for varying daylight conditions. These results provide information needed for the development of variable-rate fertilizer N application technology.

Sexual Coercion Reported by Men and Women in Prison

Abstract: An anonymous survey of 1,800 men and women in a Midwestern state prison system revealed that 104 of 516 respondents (20%) had been pressured or forced at least once to have sexual contact against their will while incarcerated. Supporting the validity of this finding, a sample of staff estimated that the sexual coercion rate was 15%. The reported incident rate was 22% for male and 7% for female respondents. Based upon descriptions of worst case incidents, at least 50% of sexual targets had been forced to have intercourse (anal, vaginal, or oral), with one fourth of the cases qualifying as gang rape. Another 10% of targets were subjected to an attempt at forced intercourse. One fourth of targets reported less severe cases of forced and pressured sexual touching. Prison staff were reported as perpetrators in 18% of the incidents. Most targets rated the immediate and long‐term effects of the incident as very negative. One half of the targets did not tell anyone about the incident, and only 29% reported the in...

Progestin and estrogen regulation of pulsatile LH release and development of persistent ovarian follicles in cattle

Abstract: When doses of progestin used commercially are administered to synchronize the stage of the estrous cycle among bovine females, fertility is reduced compared with that of untreated controls. The reduced fertility that results from the use of progestin based estrus synchrony regimens is associated with the development of persistent ovarian follicles. Persistent ovarian follicles develop as a result of the greater frequency of LH pulses that occurs during the period of treatment with progestins. The greater release of LH pulses results in enhanced secretion of 17 beta-estradiol from persistent ovarian follicles. The greater frequency of LH release or the greater secretion of 17 beta-estradiol associated with development of persistent ovarian follicles probably contributes to the reduced fertility that occurs when progestins are used to synchronize stage of the estrous cycle.

Seed longevity of 41 weed species buried 17 years in eastern and western Nebraska.

Abstract: Seed of 41 economically important weed species of the Great Plains region of the United States were buried 20 cm deep in soil in eastern and western Nebraska in 1976. The 41 species consisted of 11 annual grass, 14 annual broadleaf, 4 biennial broadleaf, and 12 perennial broadleaf species. Weed seeds were exhumed annually for germination tests the first 9 yr, then after 12 and 17 yr. Germination percentages at the two burial locations averaged over 0, 1 to 4, 5 to 8, and 9 to 17 yr of burial were 57, 28, 9, and 4% for annual grass; 47, 26, 16, and 11 % for annual broadleaf; 52, 49, 44, and 30 % for biennial broadleaf; 36, 18, 13, and 8% for perennial broadleaf; and 47, 26, 16, and 10% for all 41 weed species, respectively. Biennial broadleaf weeds showed the greatest seed germination over years. Annual grass weeds showed less seed germinability over 17 yr of burial than annual broadleaf weeds and perennial broadleaf weed species were intermediate. Weed seed germinability in soil was greater in the reduced rainfall and more moderate soil temperatures of western Nebraska than in the greater rainfall and more fluctuating soil temperatures of eastern Nebraska. The greatest seed survival among the 41 weed species was shown by common mullein, which had 95% germination after 17 yr of burial in western Nebraska. Decay rates of individual weed species in soil will be of most value to weed scientists, agriculturalists, and modelers evaluating past or designing future weed management systems.

Relationships among treatment for respiratory tract disease, pulmonary lesions evident at slaughter, and rate of weight gain in feedlot cattle

Abstract: OBJECTIVE To quantify the effects of treatment for clinical respiratory tract disease and pulmonary lesions identified at slaughter on rate of weight gain in feedlot cattle. DESIGN Prospective longitudinal study. ANIMALS 469 feedlot steers. PROCEDURE Clinical respiratory tract disease was monitored between birth and slaughter. Steers were weaned at approximately 6 months old and entered into the feedlot for a mean of 273 days. Mean daily weight gain (MDG) was monitored during the feeding period. Lungs were collected at slaughter and evaluated for gross lesions indicative of active or resolved pneumonia. RESULTS Mean daily weight gain during the feeding period was 1.30 kg, and ranged from 1.16 to 1.46 kg within individual pens. Thirty-five percent of steers received treatment for respiratory tract disease between birth and slaughter, whereas 72% had pulmonary lesions evident at slaughter. Among steers treated for clinical respiratory tract disease, 78% had pulmonary lesions, whereas 68% of untreated steers had pulmonary lesions. Pulmonary lesions at slaughter were associated (P < 0.01) with a 0.076-kg reduction in MDG during the feeding period. Treatment for clinical disease was not associated with MDG after adjustment for the effect of pulmonary lesions. CLINICAL IMPLICATIONS Treatment of clinically affected feedlot cattle may be inadequate to prevent significant production losses attributable to respiratory tract disease.

Multiple-trait Gibbs sampler for animal models: flexible programs for Bayesian and likelihood-based (co)variance component inference.

Abstract: A set of FORTRAN programs to implement a multiple-trait Gibbs sampling algorithm for (co)variance component inference in animal models (MTGSAM) was developed. The MTGSAM programs are available to the public. The programs support models with correlated genetic effects and arbitrary numbers of covariates, fixed effects, and independent random effects for each trait. Any combination of missing traits is allowed. The programs were used to estimate variance components for 50 replicates of simulated data. Each replicate consisted of 50 animals of each sex in each of four generations, for 400 animals in each replicate for two traits. For MTGSAM, informative prior distributions for variance components were inverted Wishart random variables with 10 df and means equal to the simulation parameters. A total of 15,000 Gibbs sampling rounds were completed for each replicate, with 2,000 rounds discarded for burn-in. For multiple-trait derivative free restricted maximum likelihood (MTDFREML), starting values for the variance components were the simulation parameters. Averages of posterior mean of variance components estimated using MTGSAM with informative and flat prior distributions for variance components and REML estimates obtained using MTDFREML indicated that all three methods were empirically unbiased. Correlations between estimates from MTGSAM using flat priors and MTDFREML all exceeded.99.

Phytotoxicity and Distribution of Sorgoleone in Grain Sorghum Germplasm

Abstract: The relative phytotoxicity of sorgoleone as measured by seed germination and seedling growth of selected crop and weed species and inhibition of photosynthetic oxygen evolution in atrazine-resistan...