bluuebunny/crossref_metadata_2025 huggingface dataset:
Shallow‐Water Acoustic Networks*
Authors: Proakis John G. , Rice Joseph A. , Sozer Ethem M. , Stojanovic Milica
Published: November 2003

Underwater acoustic networks are generally formed by acoustically connected ocean bottom sensor nodes, autonomous underwater vehicles (AUVs), and surface stations that serve as gateways and provide radio communication links to on‐shore stations. The QoS of such networks is limited by the low bandwidth of acoustic transmission channels, high latency resulting from the slow propagation of sound, and elevated noise levels in some environments. The long‐term goal in the design of underwater acoustic networks is to provide for a self‐configuring network of distributed nodes with network links that automatically adapt to the environment through selection of the optimum system parameters. This paper considers several aspects in the design of shallow water acoustic networks that maximize throughput and reliability while minimizing power consumption.
Information Theory
Authors: Berry Randall
Published: November 2003

Information theory provides the theoretical basis for modern digital communication systems. This articles reviews some of the basic concepts and results of information theory. The emphasis is on the fundamental limits of source coding and channel coding.
Nonlinear Effects in Optical Fibers
Authors: Chraplyvy Andrew R.
Published: November 2003

Advanced lightwave communications systems relying on optical amplification and wavelength‐division multiplexing can carry dozens of wavelengths over thousands of kilometers of optical fibers between optoelectronic regeneration points. Large optical powers confined to the small core of optical fibers over enormous distances exacerbate the effects of optical nonlinearities that can degrade signal quality. Optical nonlinearities in optical fibers include stimulated Raman scattering, stimulated Brillouin scattering, self‐phase modulation, cross‐phase modulation, and four‐photon mixing. These nonlinearities can degrade lightwave communication systems in many different ways including distortion of pulse shapes, spectral broadening, generation of new unwanted frequencies, optical crosstalk, and signal depletion. Various techniques have been developed to mitigate the effects of optical nonlinearities in fibers.
Gold Sequences
Authors: Chung Habong
Published: November 2003

The Gold sequence family [1] is one of the oldest and most well‐known families of binary sequences with optimal correlation properties. This chapter focuses on the binary Gold sequences and their relatives called Gold‐like sequences. Mathematical representations as well as the family sizes and maximum correlation magnitudes of these sequences are reviewed.
Signal Processing for Magnetic‐Recording Channels
Authors: Eleftheriou Evangelos
Published: November 2003

In the past decade, several advanced digital signal‐processing and coding techniques have been introduced into hard‐disk drives to improve the error‐rate performance at ever increasing normalized linear densities as well as to reduce manufacturing and servicing costs. The state of the art in signal processing and constrained coding for hard‐disk drives is reviewed, with emphasis on the techniques that have been used in commercial systems.
Mobile Radio Communications
Authors: Ziemer Rodger E. , Tranter William H. , Buehrer R. Michael , Rappaport Theodore S.
Published: November 2003

Mobile communications has been of interest since the earliest days of wireless communications. First applications involved ship‐to‐shore and ship‐to‐ship telegraphy as well as telegraphy to moving trains. The development of AM radio, and later FM radio, resulted in mobile voice communication systems. The development of the cellular radio concept gave to rise to mobile telephones that were both practical and inexpensive. The growth of the cellular telephone industry exceeded all expectations and, in many environments, the bulk of telephone traffic is now handled by wireless cellular systems. This article details this history and describes the essential features of mobile radio systems, including the cellular concept, mobile radio channels, and multiple access techniques. First, second and third generation commercial cellular systems are discussed and their capabilities are compared.
Authentication Codes
Authors: Johansson Thomas
Published: November 2003

This short tutorial will explain the most fundamental results on unconditionally secure authentication, including some common constructions of authentication codes and an introduction to authentication with arbitration.
Tailbiting Convolutional Codes
Authors: Handlery Marc , Johannesson Rolf , Ståhl Per
Published: November 2003

Tailbiting convolutional codes are error correcting block codes obtained from convolutional codes. Tailbiting convolutional codes have the same code rates as the underlying convolutional codes. Many properties, such as distance properties and the error correcting capability, of tailbiting convolutional codes are closely related to the corresponding properties of convolutional codes. Several good block codes can be considered as tailbiting convolutional codes. This contribution focuses on the encoding and decoding of tailbiting convolutional codes.
BISDN(Broadband Integrated Services Digital Network)
Authors: Ayanoglu Ender , Akar Nail
Published: November 2003

The subject of B‐ISDN came into being in the late 1980s, together with the concept of Asynchronous Transfer Mode (ATM). ATM is closely tied to high‐speed packet switching by means of specialized switches implemented in hardware. Due to its high speed and packet structure, ATM technology was considered attractive to unify voice, data, and video services. A unification of these services over the telephone infrastructure was attempted earlier by a standards offering known as Integrated Services Digital Network (ISDN). Consequently, this new service unification was termed Broadband ISDN (B‐ISDN). Although due to its origins, B‐ISDN is sometimes closely tied to ATM technology, the term independently represents the vision of packet‐based high‐speed integration of voice, data, and video services. It is important that in this process, guarantees to satisfy different Quality‐of‐Service (QoS) needs (in terms of delay, loss, etc) required by voice, data, and video services are provided. In this vision, what is important is the unification, or integration of services; and the underlying technology is of secondary importance. As of the early 2000s, the technology to be employed in realizing this vision seems to have shifted from its origins of ATM. In this article, our emphasis is on B‐ISDN as a service integration vision. Nevertheless, we will describe its original emphasis as the service offering of ATM as well as the path the industry seems to be taking in implementing this vision.
Magnetic Storage Systems
Authors: Thapar Hemant K.
Published: November 2003

Many similarities exist between digital storage and baseband data transmission. Instead of delivering data “from here to there”, the digital storage channel delivers data “from now to then”. This chapter provides an overview of digital magnetic storage, including the recording process underlying the generation of signal, noise, distortion, and interference, the unique characteristics and constraints of the magnetic recording channel, and the signal processing and coding methods which are deployed ubiquitously in today's magnetic disk drives.
Ternary Sequences
Authors: Helleseth Tor
Published: November 2003

Methods for constructing ternary sequences with good auto‐ and crosscorrelation properties are described. Focus is on designing families of sequences with good parameters for Code‐Division‐Multiple‐Access(CDMA) applications. Techniques for constructing good ternary sequence designs are presented using basic ideas from Galois fields, the trace function and properties of the auto‐ and crosscorrelation ofm‐sequences. Bounds on the possible parameters of the best families of sequences are presented as well as several constructions of asymptotically optimal ternary sequences. These sequence families have better parameters than possible for comparable binary designs.
Radio Resource Management in Future Wireless Networks
Authors: Zander Jens
Published: November 2003

Wireless wideband multimedia services have been a “hot” topic the last few year with the advent of the so called 3rd Generation mobile communication system. Just by looking at the existing spectrum allocations for these types of systems, clearly shows that spectrum resource management remains an important topic in the near and distant future if these service are to reach a mass marked. In this paper, we start out by briefly reviewing the classical formulation of the radio resource management problem as found in 2G mobile telephony systems and some of the current approaches in the literature. We identify the three key allocation decisions we are concerned with: the waveforms(“channels”), the access ports (or base stations) and, finally, the transmitter powers. The principle ofrandom channel allocationschemes, as found in frequency hopping or direct sequence CDMA systems, are compared with deterministic dynamic channel allocation schemes. The classical problem is then extended to a multi‐service setting were multiple quality‐of‐service requirements have to be met simultaneously. The paper closes by giving a more general outlook over some of the key problems in resource management in future wireless multimedia systems.
Powerline Communications
Authors: Hrasnica Halid , Haidine Abdelfatteh , Lehnert Ralf
Published: November 2003

The usage of electrical power supply networks for voice and data transmission, called Powerline Communications (PLC), allows realization of telecommunication systems without laying new transmission cables and therefore, saving costs and time. The PLC technology becomes nowadays more and more attractive, particularly in so‐called “last mile” networks. The main reasons for that are the deregulation of the telecommunications market and the fact that the access networks are still property of incumbent network providers. However, the powerline grids are not designed for data transmission which causes some specific performance problems in PLC networks; unfavorable noise behavior, powerful attenuation, changing impedance, electro‐magnetic compatibility with wireless services, etc. PLC networks have to operate with a limited signal power, which reduces data rates and network distances, and increases their sensitivity to disturbances. Therefore, efficient modulation and MAC layer as well as capable error handling have to be designed for PLC systems.
Permutation Codes
Authors: Viterbo Emanuele
Published: November 2003

Permutation codes are special spherical codes designed for the bandlimited Gaussian channel. A Variant I permutation code is the set of codewords obtained by taking all permutations of an initial vector in the
n
‐dimensional Euclidean space. A Variant II permutation code is the set of codewords obtained by taking all permutations and sign changes of the components of an initial vector in the
n
‐dimensional Euclidean space. These codes may be attractive because of their simple maximum likelihood decoding algorithm.
Shell Mapping
Authors: Kwok Henry K. , Jones Douglas L.
Published: November 2003

Shell mapping is an efficient technique for constellation shaping to reduce the average power of high‐rate digital communications. Constellation shaping allows in theory up to a 1.53 dB reduction in transmission power beyond unshaped modulations without increasing the bit‐error rate; current systems using shell mapping obtain up to about 1 dB power reduction. Shell mapping groups constellation points of roughly equal energy from a quadrature (QAM) constellation into concentric rings, or shells, and efficiently identifies and indexes the lowest‐energy sets of shells in a block of several successive QAM symbols using a technique based on combinatorics, generating functions, and finite‐field algebra. By providing an efficient means of mapping a large number of data bits to a multi‐dimensional shaped constellation, shell mapping allows shaping techniques to be used in practical communication systems such as the V.34 analog telephone modem standard.
Soft Output Decoding Algorithms
Authors: Pérez Lance C.
Published: November 2003

The success of turbo codes and iterative decoding in the field of channel coding for the additive white Gaussian noise (AWGN) and other channels has led to the investigation of iterative techniques in a wide range of disciplines. The essential element of all iterative processing techniques is some form of a soft‐input, soft‐output (SISO) module. A detailed description is given of the most common SISO modules, namely the soft‐output Viterbi algorithm (SOVA) and several versions of the Bahl, Cocke, Jelinek and Raviv (BCJR) or maximum a posteriori (MAP) algorithm. These algorithms are described in the context of their application to the decoding of binary convolutional codes.
Network Flow Control
Authors: Low Steven H.
Published: November 2003

Flow control schemes are distributed and asynchronous algorithms to share network resources among competing users. The goal is to share these resources fairly and efficiently, and to provide good QoS, in a stable and scalable manner. In this article, we explain these objectives and implementation constraints. We provide an introduction to mathematical models for understanding and designing such flow control schemes, and illustrate these models using TCP Vages.
Statistical Characterization of Impulsive Noise*
Authors: Giordano Arthur A. , Schonhoff Thomas A.
Published: November 2003

In this article the statistics of impulsive noise are addressed. Unlike Gaussian noise that is a single model representing many physical conditions, impulse noise requires knowledge of the underlying physical mechanisms in order to arrive at a meaningful model. An important tool used in the development of the statistics of impulse noise is the Hankel Transform. This tool provides a general technique whose use is demonstrated for the special case of atmospheric radio noise. Several models of atmospheric radio noise are presented and are referred to by one of the following: statistical‐physical, Hall, truncated Hall, mixture, Middleton Class A or B, and empirical. These models lead to distinct optimum nonlinear detector structures rather than the single optimum linear detector applicable in Gaussian noise. Selected impulsive noise models are used to compute error rate performance for several nonlinear detector structures. Although the preponderance of investigations have focused on first order statistics such as the amplitude probability distribution, it is expected that in the future studies of higher order statistics such as the pulse duration distribution will produce more accurate representations of the noise process.
Digital Filters
Authors: Lev‐Ari Hanoch
Published: November 2003

Digital filters, both fixed and adaptive, are used in telecommunication systems to shape signals and remove noise and interference. The practice of digital filter design and implementation relies on two fundamental factors: a well developed mathematical theory of signals and systems, both deterministic and statistical, and the availability of powerful digital signal processing hardware. The ongoing reduction in the cost, size and power consumption of digital hardware makes digital filtering the preferred technology in an ever widening range of applications, including matched filtering, subband decomposition/synthesis, multiplexing/demultiplexing, equalization and echo cancellation.
Antennas for Mobile Communications
Authors: Chryssomallis Michael T. , Christodoulou Christos G.
Published: November 2003

Antennas are one of the most important parts in a wireless mobile communication system and with clever design by embodying additional functions, such as diversity capability, multipath fading immunity, polarization characteristics selectivity and matching to different environmental and operational conditions, significant improvement of system performance can be achieved. In this article after introducing the necessary design requirements, the basic widely used antennas for terrestrial or land mobile systems and satellite systems are covered. Thus, types of practical antennas for special services, e.g. land base and mobile stations or satellite systems, are described, with emphasis on their properties. The main purpose of this article is to provide an overview of the antennas used in mobile communication systems. More details for further study, as well as, the design procedures of the presented antennas can be found in the reference books list and the in specific papers appearing in these books.
Pulse Position Modulation
Authors: Cariolaro G. , Erseghe T.
Published: November 2003

Pulse Position Modulation (PPM) is an historic modulation format which is finding new interest, especially in infrared optical communications. In this paper we introduce PPM in the more general context of pulse modulations. We introduce both analog PPM, for the transmission of continuous time messages, and digital PPM, for data transmission. Since nowadays the digital PPM format is universally used, a particular emphasis is given to this format.
Semiconductor Optical Amplifiers
Authors: Brisson Caroline , Dreyer Kevin F. , Leuthold Juerg
Published: November 2003

The past few decades have seen a remarkable growth in optical network capacity demand. As the data transmission rate and the network bandwidth demand keep increasing, the optical amplifier continues to play a crucial role in optical network advances. This article focuses on the Semiconductor Optical Amplifier or SOA. Basic theoretical concepts, properties, and fabrication methods are presented along with some applications.
Amplitude Modulation
Authors: Proakis John G.
Published: November 2003

This article describes the various types of amplitude modulation techniques that are used for the transmission of analog signals over wireline and wireless communication channels. The treatment includes double‐sideband, suppressed carrier amplitude modulation, conventional amplitude modulation, single‐sideband amplitude modulation and vestigial‐sideband amplitude modulation. The implementation of amplitude modulators and demodulators is also described.
Matched Filters in Signal Demodulation
Authors: Proakis John G.
Published: November 2003

Matched filters are used for signal demodulation in digital communication systems. This article describes the time‐domain and frequency‐domain properties of matched filters and illustrates their optimality in the demodulation of signals corrupted by additive white Gaussian noise.
Companders
Authors: Proakis John G.
Published: November 2003

Companders are used in communication systems to compress the dynamic range of an information‐bearing, such as a speech signal, prior to digitizing the signal and transmitting it by digital modulation. The reverse process of expanding the dynamic range of the signal is performed at the demodulator. This article describes the characteristics of companders used in conjunction with pulse code modulation (PCM) in speech coding.
Intersymbol Interference in Digital Communication Systems
Authors: Proakis John G.
Published: November 2003

This article provides a characterization of intersymbol interference (ISI) resulting from channel distortion in wireline and wireline communication systems when data is transmitted at symbol rates approaching the Nyquist rate on a single carrier frequency. The problem of signal design for eliminating ISI is treated and the Nyquist criterion is introduced. The use of a linear channel equalizer to reduce the ISI caused by channel distortion is also described.
Power Spectra of Digitally Modulated Signals
Authors: Proakis John G.
Published: November 2003

The spectral characteristics of digitally modulated signals is an important element in the design of digital communication systems for transmitting information through a communication channel. This article describes the spectral characteristics of both linearly modulated and nonlinearly modulated signals. Linearly modulated signals include pulse amplitude modulation (PAM) phase‐shift keying (PSK) and quadrature amplitude modulation (QAM). Nonlinearly modulated signals include continuous‐phase frequency‐shift keying (CPFSK) and continuous‐phase modulation (CPM).
Bioreactors, Fluidized‐Bed
Authors: Gòdia Francesc , Solà Carles
Published: November 2003

Introduction

The Fluidization Concept: General Considerations

Characteristics and Potential of Fluidized‐Bed Bioreactors

Main Aspects for the Design and Operation of Fluidized‐Bed Bioreactors

Industrial Applications of Fluidized‐Bed Bioreactors

Bibliography
Enzymes, Immobilization Methods
Authors: Sato Tadashi , Tosa Tetsuya
Published: November 2003

Bibliography
Fluorescence Techniques for Bioprocess Monitoring
Authors: Lindemann Carsten , Marose Stefan , Scheper Thomas , Nielsen Hans Ole , Reardon Kenneth F.
Published: November 2003

Introduction

Principles of Single‐Wavelength Fluorosensors

Application of Single‐Wavelength Fluorosensors

New Developments in Fluorosensor Technology and Application

Two‐Dimensional Fluorescence

Biogenic Fluorophors

Instrumentation

Hitachi F4500 Spectrofluorometer

BioView

Applications

Bibliography
Gas Hold‐up
Authors: Lübbert Andreas
Published: November 2003

Basic Definitions

Biotechnological Relevance of the Gas Holdup

Fluid–Dynamic Details

Measurement Techniques

Conclusion
Genetic Instability
Authors: Cullum John , Redenbach Matthias , Hranueli Daslav
Published: November 2003

Introduction

Mutation and Selection

Bacteria

Plasmids

Yeast and Fungi

Animal and Plant Cells

Viruses

Consequences for Good Manufacturing Practice

Bibliography
Glutamic Acid Producing Microorganisms
Authors: Kinoshita Shukuo
Published: November 2003

Introduction

Changes in Ideas Regarding Coryneform Bacteria and the Genus
Corynebacterium
in
Bergey
'
s Manual

Taxonomic Position of Glutamic Acid Producing Bacteria

Morphological and Physiological Changes of Glutamic Acid Producing Bacteria

Bibliography
L‐Isoleucine
Authors: Inui Masayuki , Terasawa Masato , Yukawa Hideaki
Published: November 2003

Introduction

Biosynthetic Pathway of Isoleucine and Its Regulation

Biosynthetic Genes of Isoleucine

Production ofL‐Isoleucine

L‐Isoleucine Production by Living Cell Reaction Process

Bibliography
Malic Acid, Production by Fumarase
Authors: Sato Tadashi , Tosa Tetsuya
Published: November 2003

Bibliography
Metabolites, Primary and Secondary
Authors: Demain Arnold L.
Published: November 2003

Bibliography
Monoacylglycerols
Authors: Yamane Tsuneo
Published: November 2003

Concerning monoacylglycerols (MAGs), structures and nomenclatures, analyses, chemical and biochemical syntheses, physico‐chemical properties, nutritional and biological effects, and natural occurrences are described. Recent advances in biochemical (i.e.lipase‐catalyzed) synthesis are mostly presented.
Optical Resolution, Biocatalysis
Authors: Omata Tetsuo , Senda Shuji , Ninomiya Yasuo
Published: November 2003

Introduction

Optical Resolution with Lipase‐Catalyzed Transesterification

Optical Resolution with Lipase‐Catalyzing Hydrolysis

Optical Resolution by Lipase‐Catalyzing Esterification

Optical Resolution by Hydantoinase‐Catalyzing Hydrolysis

Optical Resolution by Oxidoreductase‐Catalyzing Oxidation and Reduction

Conclusion

Bibliography
Organosilicon Compounds
Authors: Tanaka Atsuo , Kawamoto Takuo
Published: November 2003

Introduction

Microbial Reduction of Organosilicon Compounds

Oxidoreduction of Organosilicon Compounds by Alcohol Dehydrogenases

Bioconversion of Organosilicon Compounds by Hydrolases

Preparation of Silicon‐Containing Amino Acids

Conclusion

Bibliography
Bioprocess Control Strategy and Optimization
Authors: Dochain D.
Published: November 2003

This article introduces the basic concepts and ingredients of automatic control and optimization in the context of the control of bioprocesses. These are illustrated via a simple microbial growth example. The article also briefly discusses the advantages and drawbacks of linear versus nonlinear control, and of non‐adaptive versus adaptive control, in the context of bioprocess control.
Process Validation
Authors: Zabriskie Dane W. , Smith Thomas M. , Gardner Alan R.
Published: November 2003

Introduction

Process Validation Strategy and Documentation

Clearance Validations

Operating Ranges

Validation of Process Consistency

Postlaunch Process Validation

Future Prospects

Acknowledgments

Bibliography
Production of L‐Amino Acids by Aminoacylase
Authors: Sato Tadashi , Tosa Tetsuya
Published: November 2003

Bibliography
Professional Societies, Society for Industrial Microbiology (
SIM
)
Authors: Case Christine L. , Schwartz Robert
Published: November 2003

Background of the Organization

Awards

Local Sections

Publications

Bibliography
Acetylcholinesterase
Authors: Jewess Philip J.
Published: November 2003

Acetylcholinesterase is an enzyme present in the nervous system of all animals and is the site of actions of several important groups of insecticides. It is responsible for catalyzing the hydrolysis of the neurotransmitter acetylcholine on the post‐synaptic neural membrane, thus, preventing its continued action. Failure to remove excess acetylcholine results in continued neuronal firing, convulsions, and ultimately death of the organism. Insecticides that inhibit acetylcholinesterase, the organophosphates (OPs), carbamates, carbamoyloximes, and triazamate do so by a mechanism that resembles that of acetylcholine hydrolysis, whereby an acetyl‐enzyme intermediate is formed. However, the acyl intermediates formed by the insecticides are much more stable and result in enzymatic inhibition. Mutations in the enzyme that are less susceptible to inhibition by OP and carbamate insecticides have resulted in insecticide‐resistant pests.

Acetylcholinesterase is a membrane‐bound protein and is covalently anchored to the neuronal membrane. The structure of the enzyme from the electric rayTorpedo californicahas shown that the active site, consisting of serine, histidine, and glutamic acid residues, is at the bottom of a deep cleft in the protein. Surprisingly, a tryptophan residue was found to be responsible for binding the quaternary ammonium group of acetylcholine and other cholinergic ligands. The findings have resulted in much research to model and design new compounds that may interact with this important enzyme.
Herbicide Adjuvants
Authors: Gerald Young Bryan
Published: November 2003

Herbicide adjuvants have been a critical component of successful herbicide applications since the 1950s. An adjuvant is defined as any substance in a herbicide formulation or which may be added to the spray tank to modify herbicidal activity or application characteristics. Adjuvants have several possible functions such as serving as emulsifiers and water conditioners; reducing the surface tension of the spray droplet; and influencing size, leaf retention, contact angle, spreading, and wetting of the spray droplet. All of these characteristics can enhance herbicide uptake through interactions of the adjuvant with plant barriers associated with the leaf surface such as leaf hairs and the cuticle as well as the plasma membrane. The most common families of adjuvants are the surfactants (e.g., nonionic), oil‐based adjuvants (e.g., crop oil concentrate), and the inorganic salts (e.g., ammonium sulfate). Selection of the proper adjuvant for use with a specific herbicide can prove difficult due to complex interactions involving the herbicide, adjuvant, target plant species, spray carrier, and environmental conditions. Hence, no single adjuvant will fully optimize the activity of several herbicides on several weed species.
Analysis—Instrumentation and Techniques
Authors: Offiah Offiah O.
Published: November 2003

Chemical analysis is an established scientific approach that makes it possible to identify and quantify elements that make up a material. Therefore, chemical analysis is a function of technique, instrumentation, and application. It also involves the breakdown of molecular structures and the examination of atomic energy levels. Chemical analysis using a spectrometer is a relative technique, using calibration to convert the instrument from a light measuring device to a chemical analysis instrument. The focus of this discussion is on atomic spectroscopy as it is applicable to agrochemicals. Three modes of detection are highlighted: absorption spectrum, emission spectrum, and mass spectrum.
Macropore Flow Models
Authors: Jarvis Nicholas
Published: November 2003

In recent years, great progress has been made in improving our understanding of the impacts of macropore flow on the leaching of agrochemicals through the soil unsaturated zone, and this knowledge has been incorporated into a number of models describing these processes. Application of these models for regulation of agrochemicals would appear desirable, but at present, this is contentious and limited by a lack of information concerning the accuracy of model predictions and, therefore, the confidence that can be placed in the simulation results. This article attempts to summarize the current state‐of‐the‐art with respect to parameterization, calibration, and validation of macropore flow models and the application of these kinds of models for regulatory purposes.
Herbicides, Asulam
Authors: Pallett Ken E.
Published: November 2003

The herbicidal properties of asulam (methyl 4‐aminobenzenesulfonylcarbamate) were first described in 1965. It is used alone or in mixtures to control docks (Rumexspp.) and bracken (Pteridium aquilinum) in pastures, forestry, and orchards; wild oats (Avena fatua) in flax; and annual and perennial grasses and broad‐leaved weeds in spinach, oilseed poppies, and alfalfa. It is also used to control annual and perennial grasses, such as johnsongrass (Sorghum halepense) in sugarcane and annual grasses and broad‐leaved weeds in plantation crops. The physicochemical properties of asulam favor high phloem mobility, which contributes to the herbicidal activity against perennial weeds. The mode of action of asulam is unique for herbicides. It is an inhibitor of folic acid biosynthesis similar to the sulfonamide antimicrobial drugs, which are competitive inhibitors of 7,8‐dihydropteroate synthase (DHPS). The mechanism of selectivity to asulam is reported as having greater metabolic degradation in tolerant species. Asulam has a very low environmental, ecotoxicological, and toxicological impact. It is rapidly degraded in soil and possesses very low acute and chronic toxicity.
Auxins (Indole Auxins)
Authors: Magnus Volker , Kojić‐Prodić Biserka
Published: November 2003

The best‐known phytohormones from the auxin family contain the indole ring system substituted at its 3‐position with a short aliphatic side chain ending in a free carboxyl group. Their most common endogenous representative is indole‐3‐acetic acid (IAA). A variety of its ring‐ and side‐chain substituted derivatives have been prepared by chemical means. Indole auxins are universally required for organized growth at the cellular, tissue, and whole‐plant levels; they are widely used in plant tissue culture and for the rooting of cuttings. Native auxins are now mostly analyzed by methods based on mass spectroscopy. Plants synthesize indole auxins by pathways which may, or may not, include the amino acid, tryptophan. When the hormones become temporarily or permanently dispensable, they are conjugated with amino acids, sugars, ormyo‐inositol and metabolized by oxidation and/or decarboxylation. Auxin perception and signal transduction appear to include soluble ′auxin‐binding proteins′ and auxin‐responsive gene expression, but there are many missing links. A wealth of information on the topology of the active site of the, so far putative, auxin receptor(s) may, however, be deduced from the molecular structures of a large series of synthetic compounds with auxin activity, which have been studied by X‐ray crystallography and computational methods.
Avian Species
Authors: Mineau Pierre
Published: November 2003

The use of persistent organochlorine insecticides has had serious consequences on populations of birds of prey and fish‐eating bird species. The question now is whether current pesticides have the same potential to reduce bird populations. In order to answer this, however, the question must be defined carefully, which is one of the most difficult tasks facing any attempt to measure the impact of pesticides on birds because so many variables are involved. Overall, however, this article argues that in cases of acute poisonings in birds of prey, a few pesticides are responsible for most of the problems.
Biopesticides
Authors: Menn Julius J.
Published: November 2003

Biopesticide is an inclusive term encompassing microbial, viral, and fungal organisms, as well as entomophagous nematodes, plant‐derived pesticides (botanicals), insect pheromones as applied to mating disruption, and genes used to transform crops to express resistance to insect, fungal, herbicide, and viral attacks. Biopesticides have been gaining increased attention and interest among those concerned with developing friendly, safe, and integrated crop management compatible approaches and tactics for pest management. Despite successful results in several crop situations, biopesticides have so far not lived up to the promise of becoming a major player in the pesticide market. It is likely that greater acceptance will come via development of vastly more active agents and the growing realization that these agents can be applied in alternate treatment regimens and in combination with reduced rates of chemical pesticides.
Brassinosteroids
Authors: Hiroshi Abe , Nishikawa‐Koseki Naoko
Published: November 2003

Brassinosteroids are a sixth natural plant hormone that plays an essential regulatory role in plant growth and development. As of the year 2000, over 40 different structures of brassinosteroids had been discovered. Recent advances in research on brassinosteroid‐deficient and ‐insensitive mutants from Arabidopsis, pea, and tomato, and their molecular genetic analysis, are opening new insights into the physiology. The research on biosynthesis and metabolism is also growing rapidly. Brassinosteroids are expected to be used in the future for crop production and plant protection as a new type of plant growth regulator.
Herbicides: Cellulose Biosynthesis Inhibitors
Authors: Sabba Robert P.
Published: November 2003

The cellulose biosynthesis inhibitors are a chemically diverse group of herbicides that inhibit the biosynthesis of cellulose in susceptible plants through unknown mechanisms. These herbicides include dichlobenil, flupoxam, isoxaben, and quinclorac. As cell division is inhibited by preventing the incorporation of cellulose into new cell walls, these chemicals are most effective when used on seedlings or young plants that are growing rapidly. Dichlobenil is used for preemergence control of a number of annual grasses in addition to broadleaf weeds. Flupoxam and isoxaben are used primarily for preemergence control of annual broadleaf weeds. Quinclorac is used for preemergence or early post‐emergence control of annual grasses, but it can also be used to control a number of broadleaf weeds in a manner similar to auxinic herbicides. There are very few reports of weeds that have developed resistance to these herbicides.
Chirality and Chiral Pesticides
Authors: Kurihara Norio
Published: November 2003

Chiral agrochemicals may exhibit high enantioselectivity in xtheir biological effects. Among insecticides, many pyrethroids of chiral structure exhibit highly enantioselective insecticidal activities. There is also an example of highly enantiospecific adverse effects on mice. Organophosphorus insecticides and fungicides, triazole fungicides and plant growth regulators; acylanilide fungicides and herbicides; fungicides of other types; aryloxypropanoates; herbicides of other types; insect juvenile hormones; and pheromones frequently show high enantioselectivity in their biological activities. Among insect pheromones, various patterns of selectivity are known, such as synergistic, antagonistic, and also independent activities between the respective antipodes. A variety of preparative methods of enantiopure compounds, including the use of chiral synthons, is employed. Asymmetric induction procedures using novel chiral catalysts are also effectively employed, particularly in preparing asymmetric pyrethroids, acylanilide agrochemicals, and pheromones.
Chromatography,HPLC
Authors: Cserháti Tibor , Forgács Esther
Published: November 2003

The newest achievements in the application of adsorption and reversed‐phase high‐performance liquid chromatography (HPLC) used for the separation and quantitative determination of various pesticides is discussed in detail. A short overview of the basic principles of the technique is given, and the main theoretical equations employed for the characterization of retention processes and the quality of separation are presented. Instrumentation and troubleshooting are outlined to the extent to give a working knowledge for the solution of practical separation problems for the analysts. The sample preparation strategies such as liquid–liquid, supercritical fluid, solid‐phase and solid‐phase microextraction suitable for the enrichment, and prepurification of pesticides in complicated matrices are surveyed. The techniques employed for the measurement of pesticides classes such as organochlorine, organophosphorous, carbamate, urea, triazine, phenoxyalkyl acid, and pyrethroid pesticides are compiled and critically evaluated. The newest and the most adequate methods are described in detail, whereas the previous HPLC procedures are shortly referred.
Chromatography
TLC
Authors: Forgács Esther , Cserháti Tibor
Published: November 2003

High‐performance liquid chromatography (HPLC) has been developed as a rapid and sensitive method for the separation and quantitative determination of a wide variety of compounds present in complex matrices in very low concentration. As gas–solid and gas–liquid chromatographic techniques are only suitable for the analysis of volatile and thermostable compounds with relatively low molecular mass, HPLC methods can also separate nonvolatile, thermolabile, and large molecules. The excellent separating power, high sensitivity, and considerable diversity of solutes that could be separated with HPLC contributed to its popularity.
CIPAC
Authors: Martijn Albertus
Published: November 2003

The Collaborative International Pesticides Analytical Council Ltd. (CIPAC) was founded in 1957. It is an independent, private organization registered under the Charities Act in the United Kingdom, whose members are all official analytical chemists. CIPAC's main objective is the standardization of methods for the analysis of pesticide products and physiochemical tests for formulations. This standardization is achieved through carrying out collaborative tests according to internationally accepted protocols. Participation in these studies is open to all laboratories, both official and industrial. The results are statistically evaluated according to the IUPAC recommendations and International Standards Organization (ISO) standard 5725. When the results are acceptable, the methods are adopted as
provisional CIPAC Methods
and eventually as
CIPAC Methods
. The analytical methods are mainly based on GC and HPLC techniques. Much attention is paid to the physicochemical tests, which may consist of visual observations or of manipulations but, at present, are usually based on instrumental techniques. The methods together with identity tests and summaries of the statistical results are published in the
CIPAC Handbook
series. They are intended to be used by regulatory and enforcement bodies, by trading parties, in Quality Assurance systems, and in the FAO and World Health Organization (WHO) specifications.
Combinatorial Chemistry as Applied to the Discovery of Agrochemicals
Authors: Kleschick William A. , Parker Marshall H. , Turner James A.
Published: November 2003

Combinatorial chemistry is a proven tool for lead generation and exploration in the discovery of novel therapeutic agents. In contrast, combinatorial chemistry approaches to lead generation for agrochemical discovery are in their infancy. This report summarizes the first reported examples of the application of combinatorial chemistry or parallel synthesis to the discovery of new fungicides, insecticides, and herbicides for crop protection. The synthesis and biological activity (in vitroorin vivo) of each compound library is described. The examples include the synthesis and testing of libraries of discrete small molecules as well as the preparation of pools of compounds and subsequent deconvolution of the active pools. Compound classes covered include amides, esters, ureas, N‐substituted glycines and 2‐amino‐4‐aryloxypyrimidines. These examples clearly demonstrate the potential of the technology to significantly impact the discovery of crop protection chemicals in the coming decade.
Groundwater Modeling Tools
Authors: Mackay Neil
Published: November 2003

Groundwater is becoming an increasingly important resource, but it is apparent that it is a resource that is increasing under threat from unsustainable utilization and contamination. It is principally because of its importance as a drinking water resource that measures have been taken by regulatory authorities to protect groundwater from contamination from pesticides and other chemicals. Therefore, significant improvements in model complexity access to chemical and environmental data have increased the quality of risk assessment carried out by both regulatory and industry bodies.
Controlled Release Formulations of Pesticides
Authors: Wilkins Richard
Published: November 2003

Controlled release formulations (CRFs) are intended to improve the delivery of pesticides and related biologically active substances. The consequent improvement in efficiency reduces losses in use and has many benefits, such as reduction in exposure to both workers and the environment, particularly in minimizing leaching and evaporation. This chapter introduces the advantages of CRFs and provides a theoretical rationale for their use based on pseudo–first‐order loss kinetics, which are typical for pesticide dissipation in the environment. Thus, the greater the loss rate, especially for pesticides of short duration, the greater the potential for improvement in delivery to the target pest. As a consequence of this principle, reduced levels of pesticide delivered efficiently can be as efficacious as higher amounts of conventional formulations.

The types of CRFs are introduced and are classified as physical, chemical, or biological. The kinetics of release from CRFs is central to their successful use, and the mathematical basics of this are described. The mechanisms of release vary according to the type of formulation, and these are covered for physical and chemical types. Common release characteristics include first order, diffusion (square root of time) based, and zero order (constant). Release kinetics are usually measured under controlled laboratory conditions, but field determination are preferable.

Design and properties of CRFs then follow. The main groups of the physical‐type formulations, such as reservoirs with release‐rate controlling membranes and without membrane and the monolith or matrix structures, are those based on microencapsulated liquid cores in sprayable concentrate formulations, and polymeric matrix methods that are often fabricated as granules. The polymers used and the approaches employed for designing these types of CRFs are introduced with emphasis on encapsulation methods, such as phase separation and interfacial polymerization. In addition, other formulation types are included, such as laminates, coated granules, microparticles, matrix granules (swellable and nonswellable), matrix devices for animal and public health protection, plastic films, and mulches. The article closes with the recent biological approach to formulation based on living or dead genetically modified micro‐organisms containing proteinaceous toxins.
Insecticides, Organochlorines
Authors: Plimmer Jack R. , Gammon Derek W.
Published: November 2003

Few chlorinated organic insecticides remain in use in North America and Europe. Several have been classified as Persistent Organic Pollutants and proscribed globally. However, their considerable benefits to humanity in the past should not be overlooked nor should the lessons that were learned during the period when they were applied to control disease vectors and agricultural pests throughout the world. Organochlorine compounds were not only used as pesticides, but they also had many industrial uses. Chlorinated organic compounds were also byproducts of a number of chemical manufacturing processes, and as a result of the careless disposal and handling of wastes, quantities were applied into the environment.
LC/MS, Pesticide Residue Analysis
Authors: Krynitsky Alexander J. , Goodenowe Dayan B. , Stry James , Stout Steven J.
Published: November 2003

The very low concentration limits prescribed by regulatory agencies such as the U.S. Environmental Protection Agency (EPA) and the U.S. Food and Drug Administration (FDA) for pesticides in food, water, and soils have prompted analysts to develop analytical techniques that can determine these compounds at trace levels. High performance liquid chromatography combined with mass spectrometry (HPLC/MS) offers specificity and confirmation capabilities. Because of the above, HPLC/MS is becoming the method of choice for determining low levels (<10 ppb) of pesticides that would normally be difficult to analyze by conventional HPLC or gas chromatography (GC) methods. In this chapter, the two commonly used atmospheric pressure ionization (API) mass spectrometry techniques will be discussed: electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). Also, this chapter will discuss the advantageous and disadvantageous with the two API techniques, as well as some practical applications to the following classes of pesticides: sulfonylurea herbicides, imidazolinone herbicides, phenoxyacid herbicides, and carbamate insecticides. Finally, matrix effects will be discussed, along with ways how to optimize the API conditions.
Epidemiology of Pesticide Exposure
Authors: O'Malley Michael
Published: November 2003

This article discusses how to evaluate effects of pesticides on humans based on the information available. Basic concepts of edipemiology such as disease frequency, incidence and prevalence, sensitivity and specificity are presented. Population incidence can be estimated from illness registry data, which is ultimately derived from cases seeking medical treatment. The quality of such surveillance information is of critical importance. Design study issues involving surveillance are discussed. Various case studies involving the use of pesticides and the incidence of various types of cancers and skin diseases are given.

Outbreak studies are unique opportunities to evaluate hazards of exposure to pesticides. Outbreaks most often occur among groups of field workers. An example of an outbreak of illness in grape workers is given. Cross‐sectional (survey) studies are a means of assessing the distribution of illness in a population. Questionnaires are also discussed.

Evaluations of cause and effect are made through observational studies (includes cohort and case control studies) and experimental studies. All types are discussed and examples are given, as well as rules for evaluating these data.
EU
R
egistration
D
irective
Authors: Dewar A. J.
Published: November 2003

The European Union Registration Directive was adopted in 1991 and officially implemented in 1993. Its purpose is to remove barriers to trade in plant protection products by harmonizing registration procedures and regulatory testing requirements throughout the EU and to establish high common standards of safety and environmental stability. It also seeks to ensure that the avoidance of risks to human and animal health, groundwater, and the environment take precedence over improvement of plant production and the prevention of needless repetition of tests on animals. However, the translation of these aims into practice has proved far harder than originally envisaged.