bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light at the end of the Ca2+-release channel tunnel: structures and mechanisms involved in ion translocation in ryanodine receptor channels
Authors: Williams Alan J. , West Duncan J. , Sitsapesan Rebecca 
Published: July 2002

1. Introduction 622. Channel structure 632.1 Isoforms, primary structure and topology of Ca2+-release channels 632.2 Identification of ligand binding sites within the primary sequence of RyR 652.2.1 Calcium 662.2.2 Calmodulin 662.2.3 FK506-binding proteins 662.2.4 L-type Ca2+ channel 662.2.5 Ryanodine 672.3 The three-dimensional structure of the RyR channel 683. Channel function 703.1 RyR channel gating 703.2 Ion translocation and discrimination 713.2.1 Monovalent inorganic cations 713.2.2 Divalent inorganic cations 743.2.3 Organic monovalent cations 753.2.4 Permeant ion translocation can be blocked 753.3 Summary of ion handling in RyR 763.4 Where is the pore and what components of RyR are involved in its formation? 763.5 The mechanisms underlying ion translocation and discrimination in RyR 793.6 Does RyR employ ion–ion repulsion to attain high unitary conductance? 823.6.1 Conductance–activity relationships 833.6.2 Concentration dependence of reversal potential 833.6.3 The dependence of unitary conductance on mole-fraction 833.6.4 Effective valence of channel-blocking cations 843.6.5 Modelling ionic conduction 843.7 Factors influencing maximum conductance 853.8 Factors influencing ion entry 863.9 Theoretical design for the pore of RyR 884. What do we know about the structure of the conduction pathway in RyR? 884.1 The narrowest region of the conduction pathway – the ‘selectivity filter’ of RyR 894.2 The voltage drop across RyR – the length of the ‘pore’ 894.3 Mechanisms for ion discrimination in RyR 934.4 Musings on the structure of the RyR/InsP3R pore 955. Summary 986. Acknowledgements 987. References 98The purpose of this article is to provide a description of the current state of our
understanding of certain aspects of the relationship between the structure and function of the
ryanodine receptor (RyR). RyR is an ion channel found in the membranes of the intracellular
Ca2+ storage organelles, the endoplasmic reticulum (ER) and its counterpart in muscle cells
the sarcoplasmic reticulum (SR), where it provides a regulated pathway for the release of
stored Ca2+ during Ca2+ signalling processes such as fertilization and muscle contraction. RyR
possesses both high- and low-affinity binding sites for the plant alkaloid ryanodine; however,
whilst this ligand gives the channel its name and is of toxicological and pharmacological
interest, physiological regulation of channel gating is mediated by the binding of cytosolic
ligands (primarily Ca2+, ATP, Mg2+) and in some cases by direct coupling with a surface
membrane voltage sensor.
Ageing in American Comic Strips: 1972–1992
Authors: HANLON HEATHER , FARNSWORTH JUDY , MURRAY JUDY 
Published: July 2002

A comparison between humour and ageing from the 1970s to the 1990s and
findings from a historical study of how American artists portray older adults
showed what appears to be little change in stereotypical representations of
older people in one of the most widely read forms of humour in American
popular culture, the comic strip. Variables were age, gender, and roles of
people 56 years and over in strips published in the Washington Post during April
of 1972, 1977, 1982, 1987, and 1992.The number of older characters in American comic strips declined in the
last ten years of the study. Men were more frequently represented than
women. Women were almost equal to men in strong, positive roles despite the
fact that they were represented 870 times and men 1511 times. Most women
were portrayed in either positive or negative roles while a quarter of men were
portrayed in indeterminate roles. The negative roles of women were double
those of positive or strong roles, while the number of negative roles for men was
three times the number of positive roles.
Scale domains of abundance amongst species of mammalian Carnivora
Authors: SMALLWOOD K. SHAWN 
Published: July 2002

The spatial requirements of populations ought to be central to developing conservation strategies and ecological theory, but they are difficult to identify from the published collection of reported population estimates. Transforming population estimates into density and log values may have clouded recognition of the discontinuous relationship that exists between abundance estimates and the areas within which they were made. I used abundance estimates of terrestrial mammalian Carnivora to identify scale domains of abundance. In scale domain A, the study areas were too small to include all the individuals of the population, and abundance estimates increased propor-tionally with study area size. Scale domain B included high variation in abundance estimates, but these estimates no longer increased with increasing size of study area as they did in domain A. I refer to the smallest area in the scale domain B as the 'threshold area' (the minimum area known to support a population of the particular species). The abundance in scale domain B averaged 52 individuals amongst all but three outlier species. Scale domains C and D were also identified, and included much larger study areas and substantially larger abundance estimates.The threshold area is the first empirically-derived representation of the minimum space used by populations of each species. However, nearly half of all carnivore abundance estimates were made in areas smaller than the threshold area, and only 4% could be used to represent transitions between scale domains B, C and D. The remainder varied within domains B, C and D due to variation in environmental conditions and research methods. Most comparisons of density between sites and between species have been made without considering whether the estimates represented the true population or some collection of individuals more or less abundant than the population. Threshold area can be used as a standard area against which to estimate and compare population density, in lieu of more appropriately comparing estimates of region-wide density, which generally do not yet exist. Also, threshold area could be predicted with reasonable error rates based on a typical species' body mass, brain mass and home range size. Therefore, conservation biologists may now have a tool to identify the minimum habitat areas needed to conserve populations of carnivore species, and theoretical ecologists can relate ecological space at the population level to allometric variables.
On the bisimulation proof method
Authors: SANGIORGI DAVIDE 
Published: July 2002

The most popular method for establishing bisimilarities

among processes is to exhibit bisimulation relations. By definition,
[Rscr ] is a bisimulation relation if [Rscr ] progresses to
[Rscr ] itself, i.e., pairs of processes in [Rscr ]
can match each other's actions and their derivatives are again in
[Rscr ].We study generalisations of the method aimed at reducing the size of
the relations to be
exhibited and hence relieving the proof work needed to establish bisimilarity
results. We
allow a relation [Rscr ] to progress to a different relation [Fscr ] ([Rscr ]),
where
[Fscr ] is a function on relations. Functions that can be safely used in
this way
(i.e., such that if [Rscr ] progresses to [Fscr ] ([Rscr ]), then
[Rscr ]
only includes pairs of bisimilar processes) are sound. We give
a simple
condition that ensures soundness. We show that the class of sound functions
contains
non-trivial functions and we study the closure properties of the class
with respect to various
important function constructors, like composition, union and iteration.
These properties
allow us to construct sophisticated sound functions – and hence sophisticated
proof
techniques for bisimilarity – from simpler ones.The usefulness of our proof techniques is supported by various non-trivial
examples
drawn from the process algebras CCS and π-calculus. They include the
proof of the unique
solution of equations and the proof of a few properties of the replication
operator. Among
these, there is a novel result that justifies the adoption of a simple
form of prefix-guarded
replication as the only form of replication in the π-calculus.
On the relation between the wet delay and the integrated precipitable water vapour in the European atmosphere
Authors: Emardson T Ragne , Derks Henrico J P 
Published: July 2002

AbstractA ground‐based network of Global Positioning System (GPS) receivers can be used to determine the excess propagation path of the GPS signals. Using surface pressure data it is possible to derive the excess path caused by water vapour. This quantity is often referred to as the wet delay. We have studied the relationship between the wet delay and the integrated precipitable water vapour (IPWV), based on more than 120 000 radiosonde profiles from 38 sites in Europe. We have studied four different models based on the surface temperature, the latitude of the site, and the time of the year in different combinations. The accuracies of the models have been evaluated and also compared with the accuracy resulting from the use of published model parameters derived from radiosonde data acquired in the United States. The models using the surface temperature data yielded the smallest relative root mean square errors of 1.14% and 1.15% respectively. We find that the accuracy can sometimes be further improved, typically down to 1.02%, by adjusting the values of the model parameters to the area or site of interest. Copyright © 2000 Royal Meteorological Society
The dry intrusion perspective of extra‐tropical cyclone development
Authors: Browning K A 
Published: July 2002

AbstractThe dry intrusion is a coherent region of air descending from near tropopause‐level. It often has a clear signature in satellite imagery, especially in the water vapour channel, where it is seen as a ‘dark zone’. Parts of dry intrusions are characterised by high potential vorticity and, upon approaching a low‐level baroclinic zone, rapid cyclogenesis may be expected to ensue. The leading edges of dry intrusions are defined by cold θw‐fronts (moisture fronts). In some places the dry intrusion undercuts rearward‐ascending warm air to give an ana‐cold front. In other places it overruns the warm air to produce an upper cold θw‐front in advance of the surface cold frontHere the dry intrusion is associated with the generation of potential instability and its eventual release as showers or thunderstorms. Identification of dry intrusions provides the forecaster with additional nowcasting evidence that is especially helpful when issuing severe weather warnings. The identification of water vapour dark zones associated with dry intrusions can also form the basis of methods for validating NWP models. Through their relationship to high potential vorticity, they can provide guidance for bogussing NWP models in situations of potentially severe weather. This article provides an introduction to the structure and behaviour of dry intrusions and their relationship to other aspects of extra‐tropical cyclones. Copyright © 2004 Royal Meteorological Society
Natural language question answering:
the view from here
Authors: HIRSCHMAN L. , GAIZAUSKAS R. 
Published: July 2002

As users struggle to navigate the wealth of on-line information now available, the
need for automated question answering systems becomes more urgent. We need
systems that allow a user to ask a question in everyday language and receive an
answer quickly and succinctly, with sufficient context to validate the answer. Current
search engines can return ranked lists of documents, but they do not deliver answers
to the user.Question answering systems address this problem. Recent successes have been
reported in a series of question-answering evaluations that started in 1999 as part
of the Text Retrieval Conference (TREC). The best systems are now able to answer
more than two thirds of factual questions in this evaluation.
AN INTERVIEW WITH FRANCO MODIGLIANI
Authors: Barnett William A. , Solow Robert 
Published: July 2002

Franco Modigliani's contributions in economics and finance have transformed both fields. Although many other major contributions in those fields have come and gone, Modigliani's contributions seem to grow in importance with time. His famous 1944 article on liquidity preference has not only remained required reading for generations of Keynesian economists but has become part of the vocabulary of all economists. The implications of the life-cycle hypothesis of consumption and saving provided the primary motivation for the incorporation of finite lifetime models into macroeconomics and had a seminal role in the growth in macroeconomics of the overlapping generations approach to modeling of Allais, Samuelson, and Diamond. Modigliani and Miller's work on the cost of capital transformed corporate finance and deeply influenced subsequent research on investment, capital asset pricing, and recent research on derivatives. Modigliani received the Nobel Memorial Prize for Economics in 1985.In macroeconomic policy, Modigliani has remained influential on two continents. In the United States, he played a central role in the creation of a the Federal Reserve System's large-scale quarterly macroeconometric model, and he frequently participated in the semiannual meetings of academic consultants to the Board of Governors of the Federal Reserve System in Washington, D.C. His visibility in European policy matters is most evident in Italy, where nearly everyone seems to know him as a celebrity, from his frequent appearances in the media. In the rest of Europe, his visibility has been enhanced by his publication, with a group of distinguished European and American economists, of “An Economists' Manifesto on Unemployment in the European Union,” which was signed by a number of famous economists and endorsed by several others.This interview was conducted in two parts on different dates in two different locations, and later unified. The initial interview was conducted by Robert Solow at Modigliani's vacation home in Martha's Vineyard. Following the transcription of the tape from that interview, the rest of the interview was conducted by William Barnett in Modigliani's apartment on the top floor of a high-rise building overlooking the Charles River near Harvard University in Cambridge, Massachusetts. Those concluding parts of the interview in Cambridge continued for the two days of November 5–6, 1999 with breaks for lunch and for the excellent espresso coffee prepared by Modigliani in an elaborate machine that would be owned only by someone who takes fine coffee seriously.Although the impact that Modigliani has had on the economics and finance professions is clear to all members of those professions, only his students can understand the inspiration that he has provided to them. However, that may have been adequately reflected by Robert Shiller at Yale University in correspondence regarding this interview, when he referred to Modigliani as: “my hero.”
Comparative Analysis of Noncoding Regions of 77 Orthologous Mouse and Human Gene Pairs
Authors: Jareborg Niclas , Birney Ewan , Durbin Richard 
Published: July 2002

A data set of 77 genomic mouse/human gene pairs has been compiled from the EMBL nucleotide database, and their corresponding features determined. This set was used to analyze the degree of conservation of noncoding sequences between mouse and human. A new alignment algorithm was developed to cope with the fact that large parts of noncoding sequences are not alignable in a meaningful way because of genetic drift. This new algorithm, DNA Block Aligner (DBA), finds colinear-conserved blocks that are flanked by nonconserved sequences of varying lengths. The noncoding regions of the data set were aligned with DBA. The proportion of the noncoding regions covered by blocks >60% identical was 36% for upstream regions, 50% for 5′ UTRs, 23% for introns, and 56% for 3′ UTRs. These blocks of high identity were more or less evenly distributed across the length of the features, except for upstream regions in which the first 100 bp upstream of the transcription start site was covered in up to 70% of the gene pairs. This data set complements earlier sets on the basis of cDNA sequences and will be useful for further comparative studies.[This paper contains supplementary data that can be found at http://www.genome.com.]
Phloem Transport of Fructans in the Crassulacean Acid Metabolism Species Agave deserti1
Authors: Wang Ning , Nobel Park S. 
Published: July 2002

Abstract
Four oligofructans (neokestose, 1-kestose, nystose, and an un-identified pentofructan) occurred in the vascular tissues and phloem sap of mature leaves of Agave deserti. Fructosyltransferases (responsible for fructan biosynthesis) also occurred in the vascular tissues. In contrast, oligofructans and fructosyltransferases were virtually absent from the chlorenchyma, suggesting that fructan biosynthesis was restricted to the vascular tissues. On a molar basis, these oligofructans accounted for 46% of the total soluble sugars in the vascular tissues (sucrose [Suc] for 26%) and for 19% in the phloem sap (fructose for 24% and Suc for 53%). The Suc concentration was 1.8 times higher in the cytosol of the chlorenchyma cells than in the phloem sap; the nystose concentration was 4.9 times higher and that of pentofructan was 3.2 times higher in the vascular tissues than in the phloem sap. To our knowledge, these results provide the first evidence that oligofructans are synthesized and transported in the phloem of higher plants. The polymer-trapping mechanism proposed for dicotyledonous C3 species may also be valid for oligofructan transport in monocotyledonous species, such as A. deserti, which may use a symplastic pathway for phloem loading of photosynthates in its mature leaves.
Mapping Intercellular CO2 Mole Fraction (Ci) inRosa rubiginosaLeaves Fed with Abscisic Acid by Using Chlorophyll Fluorescence Imaging1
Authors: Meyer Sylvie , Genty Bernard 
Published: July 2002

AbstractImaging of photochemical yield of photosystem II (PSII) computed from leaf chlorophyll fluorescence images and gas-exchange measurements were performed on Rosa rubiginosa leaflets during abscisic acid (ABA) addition. In air ABA induced a decrease of both the net CO2 assimilation (An) and the stomatal water vapor conductance (gs). After ABA treatment, imaging in transient nonphotorespiratory conditions (0.1% O2) revealed a heterogeneous decrease of PSII photochemical yield. This decline was fully reversed by a transient high CO2 concentration (7400 μmol mol−1) in the leaf atmosphere. It was concluded that ABA primarily affected An by decreasing the CO2 supply at ribulose-1,5-bisphosphate carboxylase/oxygenase. Therefore, the An versus intercellular mole fraction (Ci) relationship was assumed not to be affected by ABA, and images ofCi and gs were constructed from images of PSII photochemical yield under nonphotorespiratory conditions. The distribution ofgs remained unimodal following ABA treatment. A comparison of calculations of Ci from images and gas exchange in ABA-treated leaves showed that the overestimation of Ci estimated from gas exchange was only partly due to heterogeneity. This overestimation was also attributed to the cuticular transpiration, which largely affects the calculation of the leaf conductance to CO2, when leaf conductance to water is low.
ΔpH-Dependent Photosystem II Fluorescence Quenching Induced by Saturating, Multiturnover Pulses in Red Algae1
Authors: Delphin Estelle , Duval Jean-Claude , Etienne Anne-Lise , Kirilovsky Diana 
Published: July 2002

AbstractWe have previously shown that in the red alga Rhodella violacea, exposure to continuous low intensities of light 2 (green light) or near-saturating intensities of white light induces a ΔpH-dependent PSII fluorescence quenching. In this article we further characterize this fluorescence quenching by using white, saturating, multiturnover pulses. Even though the pulses are necessary to induce the ΔpH and the quenching, the development of the latter occurred in darkness and required several tens of seconds. In darkness or in the light in the presence of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, the dissipation of the quenching was very slow (more than 15 min) due to a low consumption of the ΔpH, which corresponds to an inactive ATP synthase. In contrast, under far-red illumination or in the presence of 3-(3,4-dichlorophenyl)-1,1′-dimethylurea (only in light), the fluorescence quenching relaxed in a few seconds. The presence of N,N′-dicyclohexyl carbodiimide hindered this relaxation. We propose that the quenching relaxation is related to the consumption of ΔpH by ATP synthase, which remains active under conditions favoring pseudolinear and cyclic electron transfer.
Limonene Synthase, the Enzyme Responsible for Monoterpene Biosynthesis in Peppermint, Is Localized to Leucoplasts of Oil Gland Secretory Cells1
Authors: Turner Glenn , Gershenzon Jonathan , Nielson Erik E. , Froehlich John E. , Croteau Rodney 
Published: July 2002

Abstract
Circumstantial evidence based on ultrastructural correlation, specific labeling, and subcellular fractionation studies indicates that at least the early steps of monoterpene biosynthesis occur in plastids. (4S)-Limonene synthase, which is responsible for the first dedicated step of monoterpene biosynthesis in mint species, appears to be translated as a preprotein bearing a long plastidial transit peptide. Immunogold labeling using polyclonal antibodies raised to the native enzyme demonstrated the specific localization of limonene synthase to the leucoplasts of peppermint (Mentha× piperita) oil gland secretory cells during the period of essential oil production. Labeling was shown to be absent from all other plastid types examined, including the basal and stalk cell plastids of the secretory phase glandular trichomes. Furthermore, in vitro translation of the preprotein and import experiments with isolated pea chloroplasts were consistent in demonstrating import of the nascent protein to the plastid stroma and proteolytic processing to the mature enzyme at this site. These experiments confirm that the leucoplastidome of the oil gland secretory cells is the exclusive location of limonene synthase, and almost certainly the preceding steps of monoterpene biosynthesis, in peppermint leaves. However, succeeding steps of monoterpene metabolism in mint appear to occur outside the leucoplasts of oil gland cells.
A Specific β-Glucosidase-Aggregating Factor Is Responsible for the β-Glucosidase Null Phenotype in Maize
Authors: Esen Asim , Blanchard David J. 
Published: July 2002

Abstract
Maize (Zea mays L.) β-glucosidase was extracted from shoots of a wild-type (K55) and a “null” (H95) maize genotype. Enzyme activity assays and electrophoretic data showed that extracts from the null genotype had about 10% of the activity present in the normal genotype. Zymograms of the null genotype were devoid of any activity bands in the resolving gel, but had a smeared zone of activity in the stacking gel after native polyacrylamide gel electrophoresis. When extracts were made with buffers containing 0.5% to 2% sodium dodecyl sulfate, the smeared activity zone entered the resolving gel as a distinct band. These data indicated that the null genotypes have β-glucosidase activity, but the enzyme occurs as insoluble or poorly soluble large quaternary complexes mediated by a β-glucosidase-aggregating factor (BGAF). BGAF is a 35-kD protein and binds specifically to β-glucosidase and renders it insoluble during extraction. BGAF also precipitates β-glucosidase that is added exogenously to supernatant fluids of the null tissue extracts. The specific β-glucosidase-aggregating activity of BGAF is unequivocally demonstrated. These data clearly show that the monogenic inheritance reported for the null alleles at the β-glucosidase gene is actually for the BGAF protein, and BGAF is solely responsible for β-glucosidase aggregation and insolubility and, thus, the apparent null phenotype.