bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical Characterization of Impulsive Noise*
Authors: Giordano Arthur A. , Schonhoff Thomas A. 
Published: November 2003

AbstractIn 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

Abstract
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

Abstract
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

Abstract
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

AbstractThe 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

Abstract
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.
Companders
Authors: Proakis John G. 
Published: November 2003

Abstract
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

Abstract
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

Abstract
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

AbstractIntroductionThe Fluidization Concept: General ConsiderationsCharacteristics and Potential of Fluidized‐Bed BioreactorsMain Aspects for the Design and Operation of Fluidized‐Bed BioreactorsIndustrial Applications of Fluidized‐Bed BioreactorsBibliography
Fluorescence Techniques for Bioprocess Monitoring
Authors: Lindemann Carsten , Marose Stefan , Scheper Thomas , Nielsen Hans Ole , Reardon Kenneth F. 
Published: November 2003

AbstractIntroductionPrinciples of Single‐Wavelength FluorosensorsApplication of Single‐Wavelength FluorosensorsNew Developments in Fluorosensor Technology and ApplicationTwo‐Dimensional FluorescenceBiogenic FluorophorsInstrumentationHitachi F4500 SpectrofluorometerBioViewApplicationsBibliography
Glutamic Acid Producing Microorganisms
Authors: Kinoshita Shukuo 
Published: November 2003

Abstract

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

AbstractIntroductionBiosynthetic Pathway of Isoleucine and Its RegulationBiosynthetic Genes of IsoleucineProduction ofL‐IsoleucineL‐Isoleucine Production by Living Cell Reaction ProcessBibliography
Monoacylglycerols
Authors: Yamane Tsuneo 
Published: November 2003

AbstractConcerning 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

Abstract

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

AbstractIntroductionMicrobial Reduction of Organosilicon CompoundsOxidoreduction of Organosilicon Compounds by Alcohol DehydrogenasesBioconversion of Organosilicon Compounds by HydrolasesPreparation of Silicon‐Containing Amino AcidsConclusionBibliography
Acetylcholinesterase
Authors: Jewess Philip J. 
Published: November 2003

AbstractAcetylcholinesterase 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

AbstractHerbicide 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

AbstractChemical 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

AbstractIn 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

Abstract
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

AbstractBrassinosteroids 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

AbstractThe 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

AbstractChiral 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

AbstractThe 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

Abstract
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.