bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biaccessibility in quadratic Julia sets
Authors: ZAKERI SAEED 
Published: July 2002

This paper consists of two nearly independent parts, both of which discuss the common theme of biaccessible points in the Julia set $J$ of a quadratic polynomial $f:z\mapsto z^2+c$.In Part I, we assume that $J$ is locally-connected. We prove that the Brolin measure of the set of biaccessible points (through the basin of attraction of infinity) in $J$ is zero except when $f(z)=z^2-2$ is the Chebyshev map for which the corresponding measure is one. As a corollary, we show that a locally-connected quadratic Julia set is not a countable union of embedded arcs unless it is a straight line or a Jordan curve.In Part II, we assume that $f$ has an irrationally indifferent fixed point $\alpha$. If $z$ is a biaccessible point in $J$, we prove that the orbit of $z$ eventually hits the critical point of $f$ in the Siegel case, and the fixed point $\alpha$ in the Cremer case. As a corollary, it follows that the set of biaccessible points in $J$ has Brolin measure zero.
On-line Cartesian trajectory control of mechanisms along
complex curves
Authors: Yang Zhaoxue , Red Edward 
Published: July 2002

New methods have been developed to control a mechanism's realtime
Cartesian motion along spatially complex curves such as Non-Uniform Rational
B-splines (NURBS). The methods dynamically map the critical trajectory
parameters between parameter space, Cartesian space, and joint space. Trajectory
models that relate Cartesian tool speeds and accelerations to joint speeds and
accelerations have been generalized so that they can be applied to most classes
of robots and CNC mechanisms. A simple and efficient predictor-corrector
method uses finite difference theory to predict the parametric changes required
to generate the desired curvilinear distances along the trajectory, and then
correct the erorrs arising from this prediction. Polynomial approximation
methods successfully approximate joint speeds and accelerations rather than
require a closed-form inverse Jacobian solution. The numerical
algorithms prove to be time bounded (fixed number of computational steps), and
the generated trajectories are smooth and continuous. Both simulation and
physical experiments using an Open-Architecture Controller demonstrate the
feasibility and usefulness of the developed trajectory generation algorithms and
methods. The methods can be conducted at trajectory rates greater than 100 Hz,
depending on mechanism complexity.
Physicians and statisticians: two ways
of creating demographic health statistics in Spain, 1841–1936
Authors: RODRÍGUEZ-OCAÑA ESTEBAN , BERNABEU-MESTRE JOSEP 
Published: July 2002

I. THE CREATION OF MODERN DEMOGRAPHIC STATISTICSThe existence of a specialized administrative organization
depends on the political, economic, and social development of a country, and is indispensable for the availability of modern statistics. As more than one author has pointed out, quantitative assessments of its population reflect a government's capacity to rule. The first Spanish attempts to obtain such quantitative knowledge are found in the so-called Relaciones ordered by Philip II in the second half of the sixteenth century; they
described both European and American territories of the Crown. These early attempts, however, lacked continuity.
Novikov type inequalities for differential forms with non-isolated
zeros
Authors: BRAVERMAN MAXIM , FARBER MICHAEL 
Published: July 2002

We generalize the Novikov inequalities for 1-forms in
two different directions:
first, we allow non-isolated critical points (assuming that
they are non-degenerate in
the sense of R. Bott) and, secondly, we strengthen the inequalities by
means of
twisting by an arbitrary flat bundle. The proof uses Bismut's
modification of the
Witten deformation of the de Rham complex; it is based on an explicit estimate
on
the lower part of the spectrum of the corresponding Laplacian.In particular, we obtain a new analytic proof of the degenerate
Morse inequalities of Bott.
On utility of inductive learning in multiobjective robust
design
Authors: FOROURAGHI BABAK 
Published: July 2002

Most engineering design problems involve optimizing a number
of often conflicting performance measures in the presence
of multiple constraints. Traditional vector optimization
techniques approach these problems by generating a set
of Pareto-optimal solutions, where any specific objective
can be further improved only at the cost of degrading one
or more other objectives. The solutions obtained in this
manner, however, are only single points within the space
of all possible Pareto-optimal solutions and generally
do not indicate to designers how small deviations from
predicted design parameters settings affect the performance
of the product or the process under study.In this paper we introduce a new approach to robust design
based on the concept of inductive learning with regression
trees. Given a set of training examples relating to a multiobjective
design problem, we demonstrate how a multivariate regression
tree can utilize an information-theoretic measure of covariance
complexity to capture optimal, tradeoff design surfaces.
The novelty of generating design surfaces as opposed to
traditional points in the design space is that now designers
are able to easily determine how the responses of a product
or process vary as design parameters change. This ability
is of paramount importance in situations where design parameter
settings need to be modified during the lifetime of a product/process
due to various economic or operational constraints. As
a result, designers will be able to select optimal ranges
for design parameters such that the product's performance
indices exhibit minimal or tolerable deviations from their
target values. To highlight the advantages of our methodology,
we present a multiobjective example that deals with optimum
design of an electric discharge machining (EDM) process.
Aging of the urogenital system
Authors: Verdejo Bravo Carlos 
Published: July 2002

In this review, the principal morphological and functional changes which occur
in relationship to aging in both the genital tract and lower urinary tract are discussed.
Aging of the upper urinary tract is not considered.Much of the evidence for age-related changes comes from cross-sectional studies
with their inherent methodological limitations. Furthermore, it is difficult to
accept ‘normal aging’ criteria that do not take into consideration
the role of the acute and chronic disease so prevalent in elderly people. Thus, more
longitudinal studies are needed in order to provide a more exact analysis of the
influence of aging on the urogenital system, as for all other systems of the body.
The Storm‐Structure‐Severity method for the identification of convective storm characteristics with conventional weather radar
Authors: Visser Petrus J M 
Published: July 2002

AbstractRadar reflectivity information is often displayed in two dimensions, making it difficult to extract the structural characteristics of convective storms. The maximum radar reflectivity and the vertical profile of liquid water distribution in a vertical column of a convective cell is used to determine a structural and intensity classification of the cell. The application of this Storm‐Structure‐Severity classification is demonstrated by investigating a tornado event on 15 November 1998 in Harrismith, South Africa, by using volume‐scanned reflectivity data from the S‐band MRL‐5 radar. The regions of convective development, decay and mesocyclone evolution are identified with this classification. The method is able to extract the three‐dimensional structural information of convective storms embedded in volume‐scanned reflectivity data and present it in a simple display format. Copyright © 2001 Royal Meteorological Society
Time, tense and aspect in natural language database interfaces
Authors: ANDROUTSOPOULOS ION , RITCHIE GRAEME , THANISCH PETER 
Published: July 2002

Most existing Natural Language Database Interfaces (NLDB) were
designed to be used with
database systems that provide very limited facilities for manipulating
time-dependent data,
and they do not support adequately temporal linguistic mechanisms (verb
tenses, temporal
adverbials, temporal subordinate clauses, etc.). The database community
is becoming
increasingly interested in temporal database systems, which are intended
to store and manipulate
in a principled manner information not only about the present, but also
about the past and
future. When interfacing to temporal databases, supporting temporal linguistic
mechanisms
becomes crucial.We present a framework for constructing Natural Language Interfaces
for Temporal
Databases (NLTDB), which draws on research in tense and aspect theories,
temporal logics
and temporal databases. The framework consists of a temporal intermediate
representation
language, called TOP, an HPSG grammar that maps a wide range of questions
involving
temporal mechanisms to appropriate TOP expressions, and a provably correct
method for
translating from TOP to TSQL2, TSQL2 being a recently proposed temporal
extension of the
SQL database language. This framework was employed to implement a prototype
NLTDB.
High-Level Production of γ-Linolenic Acid in Brassica juncea Using a Δ6 Desaturase from Pythium irregulare
Authors: Hong Haiping , Datla Nagamani , Reed Darwin W. , Covello Patrick S. , MacKenzie Samuel L. , Qiu Xiao 
Published: July 2002

Abstract
γ-Linolenic acid (GLA), a nutritionally important fatty acid in mammals, is synthesized by a Δ6 desaturase. Here, we report identification of PiD6, a new cDNA from the oleaginous fungus, Pythium irregulare, encoding a 459-amino acid protein that shares sequence similarity to carboxyl-directed desaturases from various species. Expression ofPiD6 in yeast (Saccharomyces cerevisiae) revealed that it converts exogenously supplied linoleic acid into GLA, indicating that it encodes a Δ6 fatty acid desaturase. Expression of the desaturase in Brassica juncea under the control of the Brassica napus napin promoter resulted in production of three Δ6 unsaturated fatty acids (18:2–6, 9; 18:3–6, 9, 12; and 18:4–6, 9, 12, 15) in seeds. Among them, GLA (18:3–6, 9, 12) is the most abundant and accounts for up to 40% of the total seed fatty acids. Lipid class and positional analysis indicated that GLA is almost exclusively incorporated into triacylglycerol (98.5%) with only trace amounts found in the other lipids. Within triacylglycerols, GLA is more abundant at the sn-2 position.
Severity of Mutant Phenotype in a Series of Chlorophyll-Deficient Wheat Mutants Depends on Light Intensity and the Severity of the Block in Chlorophyll Synthesis
Authors: Falbel T. G. , Meehl J. B. , Staehelin L. A. 
Published: July 2002

Abstract
Analyses of a series of allelic chlorina mutants of wheat (Triticum aestivum L.), which have partial blocks in chlorophyll (Chl) synthesis and, therefore, a limited Chl supply, reinforce the principle that Chl is required for the stable accumulation of Chl-binding proteins and that only reaction centers accumulate when the supply of Chl is severely limited. Depending on the rate of Chl accumulation (determined by the severity of the mutation) and on the rate of turnover of Chl and its precursors (determined by the environment in which the plant is grown), the mutants each reach an equilibrium of Chl synthesis and degradation. Together these mutants generate a spectrum of phenotypes. Under the harshest conditions (high illumination), plants with moderate blocks in Chl synthesis have membranes with very little Chl and Chl-proteins and membrane stacks resembling the thylakoids of the lethal xantha mutants of barley grown at low to medium light intensities (which have more severe blocks). In contrast, when grown under low-light conditions the same plants with moderate blocks have thylakoids resembling those of the wild type. The wide range of phenotypes of Chl b-deficient mutants has historically produced more confusion than enlightenment, but incomparable growth conditions can now explain the discrepancies reported in the literature.
Antisense Expression and Overexpression of Biotin Carboxylase in Tobacco Leaves
Authors: Shintani D. , Roesler K. , Shorrosh B. , Savage L. , Ohlrogge J. 
Published: July 2002

Abstract
The plastid acetyl-coenzyme A carboxylase (ACCase) catalyzes the first committed step of fatty acid synthesis and in most plants is present as a heteromeric complex of at least four different protein subunits: the biotin carboxylase (BC), the biotin carboxyl carrier protein, and the α- and [beta] subunits of the carboxyltransferase. To gain insight into the subunit organization of this heteromeric enzyme complex and to further evaluate the role of ACCase in regulating fatty acid synthesis, BC expression was altered in transgenic plants. Tobacco (Nicotiana tabacum) was transformed with antisense-expression and overexpression tobacco BC constructs, which resulted in the generation of plants with BC levels ranging from 20 to 500% of wild-type levels. Tobacco plants containing elevated or moderate decreases in leaf BC were phenotypically indistinguishable from wild-type plants. However, plants with less than 25% of wild-type BC levels showed severely retarded growth when grown under low-light conditions and a 26% lower leaf fatty acid content than wild-type plants. A comparison of leaf BC and biotin carboxyl carrier protein levels in plants with elevated and decreased BC expression revealed that these two subunits of the plastid ACCase are not maintained in a strict stoichiometric ratio.
Phytochrome B and the Regulation of Circadian Ethylene Production in Sorghum1
Authors: Finlayson Scott A. , Lee In-Jung , Morgan Page W. 
Published: July 2002

Abstract
The sorghum (Sorghum bicolor L. Moench) cultivar 58M, which contains the null mutant phytochrome B gene, shows reduced photoperiodic sensitivity and exhibits a shade-avoidance phenotype. Ethylene production by seedlings of wild-type and phytochrome B mutant cultivars was monitored every 3 h, and both cultivars were found to produce ethylene in a circadian rhythm, with peak production occurring during the day. The phytochrome B mutant produces rhythmic peaks of ethylene with approximately 10 times the amplitude of the wild-type counterpart with the same period and diurnal timing. The source of the mutant's additional ethylene is the shoot. The diurnal rhythm can be produced with either light or temperature cycles; however, both light and temperature cycles are required for circadian entrainment. The temperature signal overrides the light signal in the production of diurnal rhythms, because seedlings grown under thermoperiods reversed with the photoperiod produced ethylene peaks during the warm nights. To examine the effect of extreme shading on ethylene production, seedlings were grown under dim, far-red-enriched light. This treatment duplicated the phytochrome B mutant's shade-avoidance phenotype in the wild type and caused the wild type to produce ethylene peaks similar to those observed in the mutant. The results confirm that phytochrome B is not required for proper function of circadian timing, but it may be involved in modulating physiological rhythms driven by the biological clock oscillator.
Transport, Compartmentation, and Metabolism of Homoserine in Higher Plant Cells
Authors: Aubert Serge , Curien Gilles , Bligny Richard , Gout Elisabeth , Douce Roland 
Published: July 2002

Abstract
The transport, compartmentation, and metabolism of homoserine was characterized in two strains of meristematic higher plant cells, the dicotyledonous sycamore (Acer pseudoplatanus) and the monocotyledonous weedEchinochloa colonum. Homoserine is an intermediate in the synthesis of the aspartate-derived amino acids methionine, threonine (Thr), and isoleucine. Using 13C-nuclear magnetic resonance, we showed that homoserine actively entered the cells via a high-affinity proton-symport carrier (Kmapproximately 50–60 μm) at the maximum rate of 8 ± 0.5 μmol h−1 g−1 cell wet weight, and in competition with serine or Thr. We could visualize the compartmentation of homoserine, and observed that it accumulated at a concentration 4 to 5 times higher in the cytoplasm than in the large vacuolar compartment.31P-nuclear magnetic resonance permitted us to analyze the phosphorylation of homoserine. When sycamore cells were incubated with 100 μm homoserine, phosphohomoserine steadily accumulated in the cytoplasmic compartment over 24 h at the constant rate of 0.7 μmol h−1 g−1 cell wet weight, indicating that homoserine kinase was not inhibited in vivo by its product, phosphohomoserine. The rate of metabolism of phosphohomoserine was much lower (0.06 μmol h−1 g−1 cell wet weight) and essentially sustained Thr accumulation. Similarly, homoserine was actively incorporated by E. colonum cells. However, in contrast to what was seen in sycamore cells, large accumulations of Thr were observed, whereas the intracellular concentration of homoserine remained low, and phosphohomoserine did not accumulate. These differences with sycamore cells were attributed to the presence of a higher Thr synthase activity in this strain of monocot cells.
Calcium-Dependent Protein Phosphorylation May Mediate the Gibberellic Acid Response in Barley Aleurone1
Authors: Ritchie Sian , Gilroy Simon 
Published: July 2002

Abstract
Peptide substrates of well-defined protein kinases were microinjected into aleurone protoplasts of barley (Hordeum vulgare L. cv Himalaya) to inhibit, and therefore identify, protein kinase-regulated events in the transduction of the gibberellin (GA) and abscisic acid signals. Syntide-2, a substrate designed for Ca2+- and calmodulin (CaM)-dependent kinases, selectively inhibited the GA response, leaving constitutive and abscisic acid-regulated events unaffected. Microinjection of syntide did not affect the GA-induced increase in cytosolic [Ca2+], suggesting that it inhibited GA action downstream of the Ca2+ signal. When photoaffinity-labeled syntide-2 was electroporated into protoplasts and cross-linked to interacting proteins in situ, it selectively labeled proteins of approximately 30 and 55 kD. A 54-kD, soluble syntide-2 phosphorylating protein kinase was detected in aleurone cells. This kinase was activated by Ca2+ and was CaM independent, but was inhibited by the CaM antagonistN-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (250 μm), suggesting that it was a CaM-domain protein kinase-like activity. These results suggest that syntide-2 inhibits the GA response of the aleurone via an interaction with this kinase, implicating the 54-kD kinase as a Ca2+-dependent regulator of the GA response in these cells.
Association of Ferredoxin-NADP Oxidoreductase with the Chloroplastic Pyridine Nucleotide Dehydrogenase Complex in Barley Leaves1
Authors: José Quiles Marı́a , Cuello Juan 
Published: July 2002

Abstract
Barley (Hordeum vulgare L.) leaves were used to isolate and characterize the chloroplast NAD(P)H dehydrogenase complex. The stroma fraction and the thylakoid fraction solubilized with sodium deoxycholate were analyzed by native polyacrylamide gel electrophoresis, and the enzymes detected with NADH and nitroblue tetrazolium were electroeluted. The enzymes electroeluted from band S from the stroma fraction and from bands T1 (ET1) and T2 from the thylakoid fraction solubilized with sodium deoxycholate had ferredoxin-NADP oxidoreductase (FNR; EC 1.18.1.2) and NAD(P)H-FeCN oxidoreductase (NAD[P]H-FeCNR) activities. Their NADPH-FeCNR activities were inhibited by 2′-monophosphoadenosine-5′-diphosphoribose and by enzyme incubation with p-chloromercuriphenylsulfonic acid (p-CMPS), NADPH, and p-CMPS plus NADPH. They presented Michaelis constant NADPH values that were similar to those of FNRs from several sources. Their NADH-FeCNR activities, however, were not inhibited by 2′-monophosphoadenosine-5′-diphosphoribose but were weakly inhibited by enzyme incubation with NADH, p-CMPS, and p-CMPS plus NADH. We found that only ET1 contained two polypeptides of 29 and 35 kD, which reacted with the antibodies raised against the mitochondrial complex I TYKY subunit and the chloroplast ndhA gene product, respectively. However, all three enzymes contained two polypeptides of 35 and 53 kD, which reacted with the antibodies raised against barley FNR and the NADH-binding 51-kD polypeptide of the mitochondrial complex I, respectively. The results suggest that ET1 is the FNR-containing thylakoidal NAD(P)H dehydrogenase complex.
Substrate Specificity of Barley Cysteine Endoproteases EP-A and EP-B1
Authors: Davy Anne , Svendsen Ib , Sørensen Susanne O. , Blom Sørensen Mikael , Rouster Jacques , Meldal Morten , Simpson David J. , Cameron-Mills Verena 
Published: July 2002

Abstract
The cysteine endoproteases (EP)-A and EP-B were purified from green barley (Hordeum vulgareL.) malt, and their identity was confirmed by N-terminal amino acid sequencing. EP-B cleavage sites in recombinant type-C hordein were determined by N-terminal amino acid sequencing of the cleavage products, and were used to design internally quenched, fluorogenic peptide substrates. Tetrapeptide substrates of the general formula 2-aminobenzoyl-P2-P1-P1′-P2′-tyrosine(NO2)-aspartic acid, in which cleavage occurs between P1 and P1′, showed that the cysteine EPs preferred phenylalanine, leucine, or valine at P2. Arginine was preferred to glutamine at P1, whereas proline at P2, P1, or P1′ greatly reduced substrate kinetic specificity. Enzyme cleavage of C hordein was mainly determined by the primary sequence at the cleavage site, because elongation of substrates, based on the C hordein sequence, did not make them more suitable substrates. Site-directed mutagenesis of C hordein, in which serine or proline replaced leucine, destroyed primary cleavage sites. EP-A and EP-B were both more active than papain, mostly because of their much lower Km values.
Isolation and Characterization of a Histidine Biosynthetic Gene in Arabidopsis Encoding a Polypeptide with Two Separate Domains for Phosphoribosyl-ATP Pyrophosphohydrolase and Phosphoribosyl-AMP Cyclohydrolase
Authors: Fujimori Ko , Ohta Daisaku 
Published: July 2002

AbstractPhosphoribosyl-ATP pyrophosphohydrolase (PRA-PH) and phosphoribosyl-AMP cyclohydrolase (PRA-CH) are encoded by HIS4 in yeast and byhisIE in bacteria and catalyze the second and the third step, respectively, in the histidine biosynthetic pathway. By complementing a hisI mutation of Escherichia coli with an Arabidopsis cDNA library, we isolated an Arabidopsis cDNA (At-IE) that possesses these two enzyme activities. The At-IE cDNA encodes a bifunctional protein of 281 amino acids with a calculated molecular mass of 31,666 D. Genomic DNA-blot analysis with the At-IE cDNA as a probe revealed a single-copy gene in Arabidopsis, and RNA-blot analysis showed that the At-IE gene was expressed ubiquitously throughout development. Sequence comparison suggested that the At-IE protein has an N-terminal extension of about 50 amino acids with the properties of a chloroplast transit peptide. We demonstrated through heterologous expression studies in E. coli that the functional domains for the PRA-CH (hisI) and PRA-PH (hisE) resided in the N-terminal and the C-terminal halves, respectively, of the At-IE protein.