bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing the interaction of the mammalian eIF4E‐related protein 4EHP with 4E‐BP1
Authors: Tee Andrew R , Tee Jennifer A , Blenis John
Published: April 2004

Eukaryotic initiation factor 4E‐binding protein 1 (4E‐BP1) represses translation initiation by binding to eukaryotic initiation factor 4E (eIF4E). 4E‐BP1 also binds to the eIF4E homologous protein (4EHP). We show that eIF4E‐binding mutants of 4E‐BP1 (Y54A and L59A) fail to form heterodimeric complexes with wild‐type 4EHP. In addition, the W95A mutant of 4EHP, similar to a homologous mutation in eIF4E, inhibits its binding to wild‐type 4E‐BP1. Interestingly, 4EHP over‐expression instigates a negative feedback loop that inhibits upstream signaling to 4E‐BP1 and ribosomal protein S6 kinase 1 (S6K1) whereas the 4E‐BP1‐binding‐deficient mutant of 4EHP(W95A) was unable to trigger this feedback loop. Thus, the interaction of 4EHP with 4E‐BP1 is necessary for this observed impaired signaling to 4E‐BP1 and S6K1.
Stimulation of hTAFII68 (NTD)‐mediated transactivation by v‐Src
Authors: Lee Hye Jin , Kim Sol , Pelletier Jerry , Kim Jungho
Published: April 2004

The three genes hTAFII68, EWS, and TLS (called the TET family) encode related RNA binding proteins containing an RNA recognition motif and three glycine‐, arginine‐, and proline‐rich regions in the C‐terminus and a degenerated repeat containing the consensus sequence Ser‐Tyr‐Gly‐Gln‐Ser in the N‐terminus. In many human cancers, the N‐terminal portion of hTAFII68, EWS, or TLS is fused to the DNA binding domain of one of several transcription factors including Fli‐1, ERG, ETV1, E1AF, WT1, ATF‐1, CHOP, or TEC. We have recognized the presence of several potential tyrosine phosphorylation sites within the amino‐terminal domain of hTAFII68 and have investigated the potential effects of cytoplasmic signaling on hTAFII68 function. Herein, we find that hTAFII68 is phosphorylated on tyrosine residue(s) by ectopic expression of v‐Src protein tyrosine kinase in vitro and in vivo. The hTAFII68 protein can associated with the SH3 domains of several cell signaling proteins, including v‐Src protein tyrosine kinase. We also document that full‐length v‐Src can stimulate hTAFII68‐mediated transcriptional activation, whereas deletion mutants of v‐Src are unable to exert this effect. In addition, cellular Src activity appears important for hTAFII68 function since hTAFII68‐mediated transactivation is reduced in a dose‐dependent fashion by ectopic overexpression of a dominant‐negative mutant of Src. Taken together, our results suggest that the biological activities of hTAFII68 are linked to the cytoplasmic Src signal transduction pathway.
Characterisation of the PQQ cofactor radical in quinoprotein ethanol dehydrogenase of Pseudomonas aeruginosa by electron paramagnetic resonance spectroscopy
Authors: Kay Christopher W.M , Mennenga Bina , Görisch Helmut , Bittl Robert
Published: April 2004

The binding pocket of the pyrroloquinoline quinone (PQQ) cofactor in quinoprotein alcohol dehydrogenases contains a characteristic disulphide ring formed by two adjacent cysteine residues. To analyse the function of this unusual structural motif we have investigated the wild‐type and a double cysteine:alanine mutant of the quinoprotein ethanol dehydrogenase from Pseudomonas aeruginosa by electron paramagnetic resonance (EPR) spectroscopy. Thus, we have obtained the principal values for the full rhombic g‐tensor of the PQQ semiquinone radical by high‐field (94 GHz) EPR necessary for a discrimination of radical species in dehydrogenases containing PQQ together with other redox‐active cofactors. Our results show that the characteristic disulphide ring is no prerequisite for the formation of the functionally important semiquinone form of PQQ.
Antisense inhibition of Bcr‐Abl/c‐Abl synthesis promotes telomerase activity and upregulates tankyrase in human leukemia cells1
Authors: Bakalova Rumiana , Ohba Hideki , Zhelev Zhivko , Kubo Takanori , Fujii Masayuki , Ishikawa Mitsuru , Shinohara Yasuo , Baba Yoshinobu
Published: April 2004

Clinical studies in chronic myelogenous leukemia demonstrate that the overexpression of Bcr‐Abl tyrosine kinase is usually accompanied by relatively low telomerase activity in the chronic phase, which reverts to a high activity in blast crisis. The present study was designed to investigate the cross‐talk between both enzymes, using Bcr‐Abl‐positive K‐562 and Bcr‐Abl‐negative Jurkat cell lines, treated with antisense oligodeoxyribonucleotides (ODNs) against Bcr‐Abl/c‐Abl mRNA. The decreased amount and enzyme activity of Bcr‐Abl/c‐Abl provoked telomerase activation in both cell lines. After short‐term treatment with anti‐Bcr‐Abl/c‐Abl ODNs (6 days), no variations in hTERT and phospho‐hTERT were detected. The decreased amount of Bcr‐Abl/c‐Abl was accompanied by: alterations in telomeric associated proteins–overexpression of tankyrase and decreased amount of TRF1/Tin2, cell growth arrest of K‐562 cells, reaching a plateau after 6 days treatment, and increased proliferating activity of Jurkat cells. No changes in telomere length were detected after short‐term treatment. In contrast, after long‐term treatment with anti‐Bcr‐Abl/c‐Abl ODNs (36 days), a significant elongation of telomeres and enhancement of hTERT were established, accompanied by an increased proliferating activity of both cell lines. These data provide evidence that the inhibition of Bcr‐Abl or c‐Abl synthesis keeps a potential to restore or induce cell proliferation through telomere lengthening control and telomerase activation.
The transit peptide of CP29 thylakoid protein in Chlamydomonas reinhardtii is not removed but undergoes acetylation and phosphorylation
Authors: Turkina Maria V , Villarejo Arsenio , Vener Alexander V
Published: April 2004

The surface‐exposed peptides were cleaved by trypsin from the photosynthetic thylakoid membranes isolated from the green alga Chlamydomonas reinhardtii. Two phosphorylated peptides, enriched from the peptide mixture and sequenced by nanospray quadrupole time‐of‐flight mass spectrometry, revealed overlapping sequences corresponding to the N‐terminus of a nuclear‐encoded chlorophyll a/b‐binding protein CP29. In contrast to all known nuclear‐encoded thylakoid proteins, the transit peptide in the mature algal CP29 was not removed but processed by methionine excision, N‐terminal acetylation and phosphorylation on threonine 6. The importance of this phosphorylation site is proposed as the reason of the unique transit peptide retention.
Membrane lipid composition protects Entamoeba histolytica from self‐destruction by its pore‐forming toxins
Authors: Andrä Jörg , Berninghausen Otto , Leippe Matthias
Published: April 2004

The protozoan parasite and human pathogen Entamoeba histolytica is protected against killing by its own lytic effector proteins. Amoebae withstand doses of amoebapores, their pore‐forming polypeptides, that readily kill human Jurkat T cells. Moreover, the polypeptides do not bind to the amoebic surface membrane as evidenced by using fluorescently labelled amoebapores and confocal laser microscopy. Experiments employing liposomes as a minimalistic membrane system and the major isoform amoebapore A revealed that the lipid composition of amoebic membranes prevents binding of the cytolytic molecule and that both the phospholipid ingredients and the high content of cholesterol contributes to the protection of the toxin‐producing cell.
Shear stress‐induced shedding of soluble intercellular adhesion molecule‐1 from saphenous vein endothelium
Authors: Sultan Sabena , Gosling Martin , Nagase Hideaki , Powell Janet T
Published: April 2004

Within 6 h, shear stress upregulated intercellular adhesion molecule‐1 (ICAM‐1) (two‐ to four‐fold, P<0.001) and induced matrix metalloproteinase‐2 (MMP‐2) in cultured human saphenous vein endothelial cells. By 8 h endothelial ICAM‐1 levels returned to baseline, with concomitant increase in soluble ICAM‐1 (sICAM‐1) (P<0.001) and MMP‐9 had been induced. Inclusion of a hydroxamate metalloproteinase inhibitor partially reversed the effects on ICAM‐1 and sICAM‐1 at 8 h, whereas TIMP‐1, ‐2 or ‐3 had no effect. MMP‐9, but not MMP‐2, co‐immunoprecipitated with ICAM‐1. sICAM‐1 was processed distal to Arg441, indicating that MMP‐9, docking to ICAM‐1, contributes to sICAM‐1 shedding and attenuation of the shear stress‐induced upregulation of ICAM‐1.
Mental status and pain perception during stressor tests in patients with coronary artery disease
Authors: Falcone C. , Auguadro C. , Pistorio A. , Catalano O. , Angoli L. , Specchia G.
Published: April 2004

Asymptomatic myocardial ischaemia is frequently observed in patients with coronary artery disease (CAD), both during daily life and during stressor tests. Psychological mechanisms seem to be involved in the lack of pain during myocardial ischaemia. The aim of this study was to verify in a selected population of CAD patients whether mental status might influence the pain perception during different stressor tests.

The study population contained 73 male patients (mean age 52±8 years) with stable angina during daily life, reproducible exercise‐induced myocardial ischaemia during ergometric stress test (EST) and angiographically documented CAD. All patients underwent cold pressor test (CPT), mental arithmetic stress test (MST), hyperventilation test (HT) and mental stress in association with cold pressor test (combined test, MST + CPT).

During the stressor tests, myocardial ischaemia was induced in 15/73 (21%) patients by CPT, in 18/73 (25%) by MST, in 15/73 (21%) by HT and in 19/73 (26%) by MST + CPT.

Out of the patients with stressor test‐induced myocardial ischaemia, silent ischaemia was observed in 43/73 (59%) during EST, in 10/15 (67%) during CPT, in 16/18 (89%) during MST, in 7/15 (47%) during HT and in all patients during MST + CPT (100%).

Among the ischaemic symptomatic patients during stressor tests, the lowest anginal pain intensity was experienced during MST (4.0±2.2) and the highest during EST, both at peak exercise and at the ischaemia threshold (6.6±2.9 and 5.9±2.7, respectively, p<0.05).

During MST, the prevalence of silent ischaemia was higher than was observed during the other tests. All study patients remained asymptomatic when myocardial ischaemia was induced by MST + CPT. Even the intensity of CPT induced hand pain was significantly higher during CPT alone than during MST + CPT. These results confirm that mental status may influence pain modulation.
Does dysphoric mood really predict the outcome of lumbar surgery? Methodological pitfalls in psychological research
Authors: Basler H.‐D. , Zimmer C.
Published: April 2004

This study investigates the relationship between depression and continuous pain after lumbar surgery by means of the Beck Depression Inventory (BDI). To assess the possibility that some somatic symptoms are confounded with pain, the items of the inventory were divided into a cognitive‐affective and somatic subscale. Data analysis is based on two assumptions: (1) continuous pain after surgery is more closely related to the somatic subscale than to the cognitive‐affective subscale of the BDI; and (2) postsurgical pain can be better predicted by the somatic than by the cognitive‐affective subscale presurgery.

The sample consisted of 61 patients with lumbar nucleotomy and 107 patients with lumbar spondylodesis. Treatment outcome was evaluated 6 months after surgery in the nucleotomy patients and 9 months after surgery in the spondylodesis patients. At follow‐up, subjects conducted a pain diary over a period of 2 weeks. Correlational methodology was applied.

Data analysis of both samples confirms the first assumption, whereas the second assumption is only partly confirmed. Only in the spondylodesis sample was pain intensity at follow‐up predicted by the total BDI score. Regarding the subscales, the cognitive‐affective scale, but not the somatic scale, was related to surgical outcome in this sample. The relationship between presurgical depression and pain at follow‐up failed to reach statistical significance in the nucleotomy sample. It is concluded that lack of awareness of the confounding effects of somatic items in questionnaires for the assessment of mood may contribute to erroneous conclusions drawn from studies reported in the literature.
The influence of stimulus duration on the reliability of pain ratings after nociceptive stimulation of the nasal mucosa with CO2
Authors: Lötsch J. , Marchl R. , Kobal G.
Published: April 2004

Nociceptive stimuli consisting of short pulses of gaseous CO2 applied to the nasal mucosa were investigated in 12 healthy volunteers (six males, six females) with respect to trial‐to‐trial variability. A statistical rather than a psychophysical approach was employed, focusing on test‐retest reliability. According to a randomized, volunteer‐blind crossover design, two repeated measurements for each of four stimulus durations (200, 400, 800 and 1600 ms) were performed on eight different days. During measurements, a total of 80 stimuli of 16 concentrations of CO2 (40–70% v/v in 2% steps) was applied with an interstimulus interval at 30 s. The interday variability of the pain ratings was lowest at a stimulus duration of 400 ms and highest at 200 ms. The results show that stimulus duration may affect the statistical outcome of studies on pain, and should be considered when setting up an experimental pain model.
Sprouting of A‐fibre primary afferents into lamina II in two rat models of neuropathic pain
Authors: Shortland P. , Kinman E. , Molander C.
Published: April 2004

Following peripheral nerve section, injured sensory A‐fibres into lamina II of the dorsal horn and form aberrant functional synapses. Such structural changes may underlie some of the sensory abnormalities observed in nerve‐injured patients, including neuropathic pain. This study compared the ability of intact and injured A‐fibres to sprout in two experimental models of neuropathic pain, where the onset and presence of abnormal behaviours indicative of neuropathic pain have been well described. Rats received either a unilateral chronic constriction injury of the sciatic nerve (CCI) or lesion of the L5 spinal nerve (SNL). The central distribution of the injured and uninjured afferents labelled with choleragenoid conjugated to horseradish peroxidase (B‐HRP) was examined at different postoperative survival times. In both models, the contralateral uninjured side, used for control nerve or ganglion injections, showed labelling of the L3–6 spinal segments in laminae I, III‐V, leaving lamina II unlabelled. In CCI rats, injured sciatic afferents sprouted in lamina II of the L4–5 dorsal horn by 10 days postinjury. In SNL rats, injured L5 afferents sprouted into lamina II of the L4–5 dorsal horn by 24 h postinjury and were robust from 3 to 10 days. In both models, the labelling in lamina II was absent by 4 months. Labelling of the adjacent uninjured saphenous or intact L4 spinal nerve afferents did not reveal A‐fibre sprouting. As the time‐course of sprouting of injured A‐fibres parallels the previously described behaviour interpreted as neuropathic pain in these models, this may be a phenomenon that contributes to sensory abnormalities such as ongoing pain and mechanical hypersensitivity.
E-Z Reader's assumptions about lexical processing: Not so easy to define the two stages of word identification?
Authors: Andrews Sally
Published: April 2004

E-Z Reader's account of the interaction between oculomotor and cognitive processes depends critically on distinguishing between early and late stages of lexical processing, because this distinction allows saccadic programming to be decoupled from shifts of attention. Precisely specifying the nature of this distinction has important implications both for current models of lexical retrieval and for the development of E-Z Reader 8.
The problems that generate the rationality debate are too easy, given what our economy now demands
Authors: Bringsjord Selmer , Yang Yingrui
Published: April 2004

Stanovich & West (S&W), following all relevant others, define the rationality debate in terms of human performance on certain well-known problems. Unfortunately, these problems are very easy. For that reason, if System 2 cognition is identified with the capacity to solve them, such cognition will not enable humans to meet the cognitive demands of our technological society. Other profound issues arise as well.
How can selection-for-perception be decoupled from selection-for-action?
Authors: Beauvillain Cécile , Pouget Pierre
Published: April 2004

Evidence is presented for the notion that selection-for-perception and selection-for-action progress in parallel to become tightly coupled at the saccade target before the execution of the movement. Such a conception might be incorporated in the E-Z Reader model of eye-movement control in reading.
Just bubbles?
Authors: Duch Włodzisław
Published: April 2004

Lehar misrepresents the Neuron Doctrine and indirect realism. His conclusions on consciousness are unjustified. The Bubble Gestalt perceptual modeling disconnected from neuroscience has no explanatory power.
Reading the scene: Application of E-Z Reader to object and scene perception
Authors: De Graef Peter , Germeys Filip
Published: April 2004

We discuss five basic principles of E-Z Reader in terms of their potential for models of eye-movement control in object and scene perception. We identify several obstacles which may hinder the extrapolation of the E-Z Reader principles to nonreading tasks, yet find that sufficient similarities remain to justify using E-Z Reader as a guide for modeling eye-movement control in object and scene perception.
Are there two populations of refixations in the reading of long words?
Authors: Doré-Mazars Karine , Vergilino-Perez Dorine , Collins Thérèse
Published: April 2004

This commentary focuses on the limitations of the E-Z Reader model in its attempt to explain refixation saccades in reading. Listing factors that influence probability of refixating leads the model to assume two sorts of refixations. However, taking into account data on the metrics of refixation saccades allows us to propose an alternative explanation for empirical observations reported in the literature.
Steven Lehar's Gestalt Bubble model of visual experience: The embodied percipient, emergent holism, and the ultimate question of consciousness
Authors: Gunderson Keith
Published: April 2004

Aspects of an example of simulated shared subjectivity can be used both to support Steven Lehar's remarks on embodied percipients and to triangulate in a novel way the so-called “hard problem” of consciousness which Lehar wishes to “sidestep,” but which, given his other contentions regarding emergent holism, raises questions about whether he has been able or willing to do so.
The game of word skipping: Who are the competitors?
Authors: Engbert Ralf , Kliegl Reinhold
Published: April 2004

Computational models such as E-Z Reader and SWIFT are ideal theoretical tools to test quantitatively our current understanding of eye-movement control in reading. Here we present a mathematical analysis of word skipping in the E-Z Reader model by semianalytic methods, to highlight the differences in current modeling approaches. In E-Z Reader, the word identification system must outperform the oculomotor system to induce word skipping. In SWIFT, there is competition among words to be selected as a saccade target. We conclude that it is the question of competitors in the “game” of word skipping that must be solved in eye movement research.
Serial programming for saccades: Does it all add up?
Authors: Findlay John M. , White Sarah J.
Published: April 2004

This commentary analyses the quantitative parameters of Reichle et al.'s model, using estimates when explicit information is not provided. The analysis highlights certain features that appear to be necessary to make the model work and ends by noting a possible problem concerning the variability associated with oculomotor programming.
Psychological relativity
Authors: Laming Donald
Published: April 2004

“Psychological relativity” means that “an observation is a relationship between the observer and the event observed.” It implies a profound distinction between “the internal first-person as opposed to the external third-person perspective.” That distinction, followed through, turns Lehar's discourse inside-out. This commentary elaborates the notion of “psychological relativity,” shows that whereas there is already a natural science of perceptual report, there cannot also be a science of perception per se, and draws out some implications for our understanding of phenomenal consciousness.
Frontal lobe functions in reading: Evidence from dyslexic children performing nonreading saccade tasks
Authors: Fischer Burkhart
Published: April 2004

Reichle et al. show that saccades in reading are controlled by linguistic processing. The authors' Figure 13 shows the parietal and frontal eye fields as parts of a neural implementation. This commentary presents data from dyslexics performing nonreading saccade tasks. The dyslexics exhibit deficits in antisaccade control. Improvement of the deficits is achieved in 85% of the cases and results in advantages in learning how to read.
Double trouble for Gestalt Bubbles
Authors: Lloyd Dan
Published: April 2004

The “Gestalt Bubble” model of Lehar is not supported by the evidence offered. The author invalidly concludes that spatial properties in experience entail an explicit volumetric spatial representation in the brain. The article also exaggerates the extent to which phenomenology reveals a completely three-dimensional scene in perception.
Visual word recognition and oculomotor control in reading
Authors: Huestegge Lynn , Grainger Jonathan , Radach Ralph
Published: April 2004

A central component in the E-Z Reader model is a two-stage word processing mechanism made responsible for both the triggering of eye movements and sequential shifts of attention. We point to problems with both the verbal description of this mechanism and its computational implementation in the simulation. As an alternative, we consider the use of a connectionist processing module in combination with a more indirect form of cognitive eye-movement control.
The unified electrical field
Authors: MacKay William A.
Published: April 2004

The electrophysiological perspective presents an electrical field that is continuous throughout the body, with an intense focus of dynamically structured patterns at the cephalic end. That there is indeed an isomorphic mapping between the detailed holistic patterns in this field and in perception (at some level) seems certain. Temporal binding, however, may be a greater challenge than spatial binding.
The soap bubble: Phenomenal state or perceptual system dynamics?
Authors: Marković Slobodan
Published: April 2004

The Gestalt Bubble model describes a subjective phenomenal experience (what is seen) without taking into account the extraphenomenal constraints of perceptual experience (why it is seen as it is). If it intends to be an explanatory model, then it has to include either stimulus or neural constraints, or both.
Selection for fixation and selection for orthographic processing need not coincide
Authors: Inhoff Albrecht W. , Shindler Kelly
Published: April 2004

The E-Z Reader model assumes that the parafoveal selection for fixation and the subsequent selection for attention allocation encompass the same spatially distinct letter cluster. Recent data suggest, however, that an individual letter sequence is selected for fixation and that more than one letter sequence can be selected for attention allocation (processing).
Consciousness as phenomenal ether?
Authors: Revonsuo Antti
Published: April 2004

The Gestalt Bubble model of visual consciousness is a courageous attempt to take the first-person perspective as primary in the study of consciousness. I have developed similar ideas as the Virtual Reality Metaphor of consciousness (Revonsuo 1995; 2000). I can, hence, only agree with Lehar about the general shape of a proper research strategy for the study of consciousness. As to the metaphysical basis of the research program, I have, however, several reservations about panexperientialism.
Psycholinguistic processes affect fixation durations and orthographic information affects fixation locations: Can E-Z Reader cope?
Authors: Liversedge Simon P. , White Sarah J.
Published: April 2004

This commentary focuses on two aspects of eye movement behaviour that E-Z Reader 7 currently makes no attempt to explain: the influence of higher order psycholinguistic processes on fixation durations, and orthographic influences on initial and refixation locations on words. From our understanding of the current version of the model, it is not clear how it may be readily modified to account for existing empirical data.
Gestalt Bubble and the genesis of space
Authors: Rosenthal Victor , Visetti Yves-Marie
Published: April 2004

Lehar (rightly) insists on the volumetric character of our experience of space. He claims that three-dimensional space stems from the functional three-dimensional topology of the brain. But his “Gestalt Bubble” model of volumetric space bears an intrinsically static structure – a kind of theater, or “diorama,” bound to the visual modality. We call attention to the ambivalence of Gestalt legacy and question the status and precise import of Lehar's model and the phenomenology that motivates it.
Basic assumptions concerning eye-movement control during reading
Authors: McConkie George W. , Yang Shun-Nan
Published: April 2004

Reichle et al. specify two assumptions as being basic to E-Z Reader: Words are sequentially attended during fixations, and saccades are triggered by a cognitive event. We point out that there is little evidence for the first assumption and counterevidence for the second. Also, the labile/nonlabile stage distinction in saccade preparation seems to be contrary to current evidence. An alternative explanation of saccade onset times in reading assumes that saccades are strategically generated, independent of language processing, but are delayed on a probabilistic basis by processing difficulties.
The eye-movement engine
Authors: Murray Wayne S.
Published: April 2004

E-Z Reader fits key parameters from one corpus of eye movement data, but has not really been tested with new data sets. More critically, it is argued that the key mechanism driving eye movements – a serial process involving a proportion of word recognition time – is implausible on the basis of a broad range of experimental findings.
Spatial phenomenology requires potential illumination
Authors: Schirillo James A.
Published: April 2004

Collapsing three-dimensional space into two violates Lehar's “volumetric mapping” constraint and can cause the visual system to construct illusory transparent regions to replace voxels that would have contained illumination. This may underlie why color constancy is worse in two dimensions, and argues for Lehar to revise his phenomenal spatial model by putting “potential illumination” in empty space.
On the perceptual and neural correlates of reading models
Authors: Osaka Naoyuki
Published: April 2004

The current model appears comprehensive but is probably not applicable to a writing system like Japanese, which has unspaced text, because the model is mainly based on English. The span size difference (smaller for Japanese than for English) may be a result of high-level working memory-based attentional processing and not of low-level processing. Further, neural correlates of the model are discussed in terms of central executive function.
If vision is “veridical hallucination,” what keeps it veridical?
Authors: Tse Peter Ulric
Published: April 2004

If perception is constructed, what keeps perception from becoming mere hallucination unlinked to world events? The visual system has evolved two strategies to anchor itself and correct its errors. One involves completing missing information on the basis of knowledge about what most likely exists in the scene. For example, the visual system fills in information only in cases where it might be responsible for the data loss. The other strategy involves exploiting the physical stability of the environment as a reference frame with respect to which the eyes and body can move.
Regressions and eye movements: Where and when
Authors: Perea Manuel , Carreiras Manuel
Published: April 2004

Reichle et al. argue that the mechanism that determines where to fixate the eyes is controlled mostly by low-level processes. Therefore, unlike other competing models (e.g., the SWIFT model), the E-Z Reader model cannot account for “global” regressions as a result of linguistic difficulties. We argue that the model needs to be extended to account for regressive saccades.
Attention, saccade programming, and the timing of eye-movement control
Authors: Radach Ralph , Deubel Heiner , Heller Dieter
Published: April 2004

E-Z Reader achieves an impressive fit of empirical eye movement data by simulating core processes of reading in a computational approach that includes serial word processing, shifts of attention, and temporal overlap in the programming of saccades. However, when common assumptions for the time requirements of these processes are taken into account, severe constraints on the time line within which these elements can be combined become obvious. We argue that it appears difficult to accommodate these processes within a largely sequential modeling framework such as E-Z Reader.
Alternative paradigmatic hypotheses cannot be fairly evaluated from within one's own paradigmatic assumptions
Authors: Lehar Steven
Published: April 2004

To avoid endless and futile debate, critics of an alternative paradigmatic hypothesis cannot simply state their own paradigmatic assumptions as if they were plain fact while dismissing those of the opposition as self-evidently absurd, because it is exactly those initial assumptions that are brought into question by the paradigmatic proposal. Perceived incredibility is no valid ground for rejection of a paradigm whose alternatives are at least equally incredible, and arguably more so.
Methodologies for comparing complex computational models of eye-movement control in reading: Just fitting the data is not enough
Authors: Reilly Ronan , Radach Ralph
Published: April 2004

As the number of computational models of eye-movement control in reading increases, so too will their coverage and complexity. This will make their comparison and testing increasingly challenging. We argue here that there is a need to develop a methodology for constructing and evaluating such models, and outline aspects of a possible methodology.
Where to look next? The missing landing position effect
Authors: Underwood Geoffrey
Published: April 2004

The E-Z Reader 7 model is powerful but incomplete. When programming the saccade to the next word, we take into account the familiarity of the letter sequences at the beginning of that word. This landing position effect is well established, but is neglected in the model. A possible locus for the effect is suggested within the E-Z Reader framework.
The basic assumptions of E-Z Reader are not well-founded
Authors: Vitu Françoise
Published: April 2004

This commentary focuses on the two basic assumptions of the E-Z Reader model, discussing the possibility that adjacent words in reading may be processed in parallel rather than serially, and presenting evidence against a cognitive control of eye guidance in reading.
Eye movements in reading: Models and data
Authors: Rayner Keith , Pollatsek Alexander , Reichle Erik D.
Published: April 2004

The issues the commentators have raised and which we address, include: the debate over how attention is allocated during reading; our distinction between early and late stages of lexical processing; our assumptions about saccadic programming; the determinants of skipping and refixations; and the role that higher-level linguistic processing may play in influencing eye movements during reading. In addition, we provide a discussion of model development and principles for evaluating and comparing models. Although we acknowledge that E-Z Reader is incomplete, we maintain that it provides a good framework for systematically trying to understand how the cognitive, perceptual, and motor systems influence the eyes during reading.
Trends in the Southern Hemisphere polar vortex in NCEP and ECMWF reanalyses
Authors: Renwick James A.
Published: April 2004

A comparison of tropospheric and stratospheric height fields from ECMWF and NCEP/NCAR reanalyses during 1958–2001 indicates a trend towards a strengthening Antarctic polar vortex. The reanalyses agree well on a daily basis over the Southern Hemisphere, after the advent of satellite observations in 1979. Linear trends in 500 hPa and 50 hPa geopotential height are in close spatial agreement in the period 1980–2001 (correlations >0.8), showing falling heights over Antarctica and strengthening zonal winds above the southern oceans during summer and autumn. Prior to 1980, stratospheric trends agree well (spatial correlations ≥0.7), suggesting a rise in heights over Antarctica and a weakening polar vortex since the late 1950s. Tropospheric trends are not as consistent prior to 1980, but show similar qualitative features. The strong trends observed in the past 20 years dominate the full record, but there are suggestions of cyclical components on the decadal time scale.
Response of neutral atom emissions in the low‐latitude and high‐latitude magnetosheath direction to the magnetopause motion under extreme solar wind conditions
Authors: Taguchi S. , Collier M. R. , Moore T. E. , Fok M.‐C. , Singer H. J.
Published: April 2004

On 11 April 2001 the high velocity and density of the solar wind and the strong southward interplanetary magnetic field moved the dayside magnetopause inside of geosynchronous orbit. The Low Energy Neutral Atom (LENA) imager on the Imager for Magnetopause‐to‐Aurora Global Exploration (IMAGE) spacecraft in the magnetosphere observed significant emission in the magnetosheath direction. The total neutral atom flux from the dayside region, ignoring the neutral solar wind flux directly from the Sun, shows a threefold enhancement, and each of the three increases is coincident with the occurrence of the magnetopause inside 6.6 RE. Observations by LENA also show that emission in the direction of the low‐latitude and high‐latitude magnetosheath is modulated in such a manner that the sources shift earthward/sunward and equatorward/poleward in the low‐latitude and high‐latitude sheath, respectively. A model based on the distributions of the sheath flux and of the number density of the hydrogen exosphere explains these characteristics as a result of the motion of the magnetopause having an indentation at the cusp, suggesting a means for monitoring the cusp motion using IMAGE/LENA.
Variations in lower thermosphere dynamics at midlatitudes during intense geomagnetic storms
Authors: Goncharenko Larisa P. , Salah Joseph E. , Foster John C. , Huang Chaosong
Published: April 2004

High‐resolution observations of the dynamics of the ionospheric E region (100–150 km) at midlatitudes have been made with the incoherent scatter radar at Millstone Hill (42.6°N, 71.5°W) during several intense geomagnetic storms (Kp ∼ 8–9). These included the storms of 25 September 1998, 15 July 2000, and 31 March 2001. The observations reveal electric fields of up to 100 mV/m during these events and indicate E region zonal plasma drifts of 300–1000 m/s, westward in the evening sector and eastward in the morning sector, with smaller meridional drifts. The tidal pattern of neutral winds in the lower thermosphere is heavily disrupted. The zonal component of the neutral wind follows convection‐driven ion flow, while the meridional component shows a more complex response to geomagnetic forcing.
Lagrangian transport model forecasts and a transport climatology for the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) measurement campaign
Authors: Forster Caroline , Cooper Owen , Stohl Andreas , Eckhardt Sabine , James Paul , Dunlea Edward , Nicks Dennis K. , Holloway John S. , Hübler Gerd , Parrish David D. , Ryerson Tom B. , Trainer Michael
Published: April 2004

On the basis of Lagrangian tracer transport simulations this study presents an intercontinental transport climatology and tracer forecasts for the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) aircraft measurement campaign, which took place at Monterey, California, in April–May 2002 to measure Asian pollution arriving at the North American West Coast. For the climatology the average transport of an Asian CO tracer was calculated over a time period of 15 years using the particle dispersion model FLEXPART. To determine by how much the transport from Asia to North America during ITCT 2K2 deviated from the climatological mean, the 15‐year average for April and May was compared with the average for April and May 2002 and that for the ITCT 2K2 period. It was found that 8% less Asian CO tracer arrived at the North American West Coast during the ITCT 2K2 period compared to the climatological mean. Below 8‐km altitude, the maximum altitude of the research aircraft, 13% less arrived. Nevertheless, pronounced layers of Asian pollution were measured during 3 of the 13 ITCT 2K2 flights. FLEXPART was also successfully used as a forecasting tool for the flight planning during ITCT 2K2. It provided 3‐day forecasts for three different anthropogenic CO tracers originating from Asia, North America, and Europe. In two case studies the forecast abilities of FLEXPART are analyzed and discussed by comparing the forecasts with measurement data and infrared satellite images. The model forecasts underestimated the measured CO enhancements by about a factor of 4, mainly because of an underestimation of the Asian emissions in the emission inventory and because of biomass‐burning influence that was not modeled. Nevertheless, the intercontinental transport and dispersion of pollution plumes were qualitatively well predicted, and on the basis of the model results the aircraft could successfully be guided into the polluted air masses.
Rapid transient changes in northeast Atlantic deep water ventilation age across Termination I
Authors: Skinner L. C. , Shackleton N. J.
Published: April 2004

A sequence of accelerator mass spectrometry (AMS) 14C dates performed on benthic and planktonic foraminifera from a northeast Atlantic deep‐sea core (MD99‐2334K; 37°48′N, 10°10′W; 3146 m) permit the reconstruction of deep water “14C ventilation ages” across the last deglaciation. The records from MD99‐2334K have been placed on the GISP2 timescale via the synchrony of temperature changes recorded in the Greenland ice cores and in North Atlantic planktonic δ18Occ (calcite δ18O). On the basis of a range of estimates for past source water Δ14C, this permits the estimation of 14C projection ventilation ages for comparison with benthic‐planktonic 14C age differences. Although the accurate estimation of past ventilation ages is precluded by unknown deep water Δ14C source signatures, and by uncertainty regarding the extent of deep water mixing, it is clear that deep water ventilation in the northeast Atlantic was significantly reduced during the last glaciation, increased abruptly coincident with the Bølling‐Allerød warming, and rapidly became reduced again during the Younger Dryas cold reversal. The character of these changes is consistent with a varying dominance of North Atlantic Deep Water (NADW) versus Antarctic Bottom Water (AABW). Parallel benthic δ13C, deep water temperature (Tdw), and deep water δ18O (δ18Odw) estimates support this inference. The fact that deglacial changes in the deep water radiocarbon content of the northeast Atlantic run parallel to opposite changes in atmospheric radiocarbon content, and in parallel with Greenland temperature fluctuations, unequivocally implicates changes in ocean circulation in deglacial climate evolution and illustrates the capacity for the deep ocean to respond and contribute to abrupt climate change.
Response of clonal growth in Phyllostachys praecox f. prevernalis to changing light intensity
Authors: Yue Chunlei , Chang Jie , Wang Kuihong , Zhu Yinmei
Published: April 2004

The morphological plasticity and biomass allocation pattern of clones of Phyllostachys praecox f. prevernalis were studied at four light intensities of 100, 70, 50 and 30% of sunlight. The results showed that ramet number and total biomass of clones were positively linearly correlated with light intensity. Under different light intensities, total rhizome length of clones and length of spacers were significantly different, indicating that rhizome and spacer both had considerable morphological plasticity. Internode length and branching angle did not differ significantly among different treatments. Under the lowest light intensity, the clone invested more biomass to aerial shoot production. The adaptation strategy of clone in P. praecox f. prevernalis for light is also discussed.
Seed viability in relation to pollinator availability in Banksia baxteri
Authors: Wooller S. J. , Wooller R. D.
Published: April 2004

Seed set was examined in relation to access to inflorescences by large or small invertebrates, vertebrates, all animal visitors or none. Seed predation by insects was substantial (35–46%) and unrelated to pollinator access. The fewer the categories of animals allowed access to flowers, the greater the proportion of unpredated seeds that were aborted. Germination rates (83–96%) of filled seeds were unrelated to pollinator access, as were survival and size of seedlings at 4 months old. Overall, only 16% of seeds initiated by selfing after exclusion of all pollen vectors resulted in 4-month-old seedlings, compared with 33% of seeds initiated after access by all or larger animal visitors. Pollen and resource limitation are likely to account for only some of these findings. Rather, we suggest that preferential development of progeny fertilised by outcross pollen from other, especially distant, individuals may also play a role in reducing seed formation.
Secondary walls in hyaline cells of Sphagnum
Authors: Kremer Celeste L. , Drinnan Andrew N.
Published: April 2004

The cytoskeleton and ultrastructural events associated with cell differentiation and secondary cell wall and pore formation in hyaline cells of Sphagnum are investigated. Microtubules reorient from random arrays in undifferentiated hyaline cells to transverse arrays in elongating cells. Once cells are fully elongated, broad bands of microtubules aggregate into a spiral that predicts the site of secondary cell wall deposition. The secondary wall has a similar fibrillar composition to the primary wall. After the secondary wall is deposited, the thin primary wall covering the pore breaks down, usually by cell-wall degradation at the centre of the pore and around its margin. Finally, the hyaline cell undergoes cytoplasmic degeneration. The orientation of microtubules associated with hyaline-cell formation and secondary cell wall patterning resembles ultrastructural development in tracheary elements of higher plants. The similarities in cytoskeletal arrays during cell differentiation and secondary-wall formation suggest a fundamental pathway of development shared by bryophytes and higher plants.
Genetic structuring of the stream lily Helmholtzia glaberrima (Philydraceae) within Toolona Creek, south-eastern Queensland
Authors: Prentis Peter J. , Vesey A. , Meyers N. M. , Mather P. B.
Published: April 2004

The distribution of genetic variation among five isolated sites of the riparian species Helmholtzia glaberrima (J.D.Hook) was examined in Toloona Creek (28�13′S, 153�07′E) by using dominant amplified fragment length polymorphism (AFLP) markers. From the 137 fragments assessed, analysis of molecular variance (AMOVA) showed that most genetic variability occurred within sites (68%), although high (32%) variation also occurred among sites. Highly significant pairwise θ estimates among all sampled sites suggest that gene flow is restricted in H. glaberrima. Levels of within-site diversity were intermediate and significantly different across the sampled sites. Significant levels of linkage disequilibrium were detected at all sites except TC3. Differences in linkage disequilibrium and genetic diversity among the sites suggest that sites may have been founded by different numbers of colonists. Mantel tests found no correlation between geographic and genetic distance and significant levels of linkage disequilibrium were detected at the total site level, supporting a non-equilibrium model of population structure. The observed pattern of non-equilibrium population structure and genetic variation in H. glaberrima are best explained by a classical metapopulation model.
Fire spread across pine needle fuel beds: characterization of temperature and velocity distributions within the fire plume
Authors: Marcelli Thierry , Santoni Paul A. , Simeoni Albert , Leoni Eric , Porterie Bernard
Published: April 2004

The aim of this article is twofold. First, it concerns the improvement of knowledge on the fundamental physical mechanisms that control the propagation of forest fires. To proceed, an experimental apparatus was designed to study, in laboratory conditions, the flame of a fire spreading across a pine needle fuel bed. Characterization of temperature was managed by using a reconstruction method based on a double thermocouple probe technique developed recently. The vertical gas velocity distribution was derived from the previous reconstructed signals by measuring the transit time of a thermal fluctuation between two points of the flow. Second, the experimental data were used for the testing of a physical two-phase model of forest fire behavior in which the decomposition of solid fuel constituting a forest fuel bed as well as the multiple interactions with the gas phase are represented.
Prescribed fire, soils, and stream water chemistry in a watershed in the Lake Tahoe Basin, California
Authors: Stephens Scott L. , Meixner Thomas , Poth Mark , McGurk Bruce , Payne Dale
Published: April 2004

Before Euro-American settlement fire was a common process in the forests of the Lake Tahoe Basin. The combination of drought, fire suppression, and past harvesting has produced ecosystems that are susceptible to high-severity wildfires. Consequently, a program of prescribed fire has been recommended but there is incomplete understanding of the ecological effects of fuels treatments, especially with regard to how treatments will affect the flow of nutrients to Lake Tahoe. Nitrogen and phosphorus are the most important nutrients affecting algal growth, and thus lake clarity. Existing data demonstrate a long-term shift from a co-limitation by both nitrogen and phosphorus to phosphorus limitation. Two high-consumption, moderate-intensity prescribed fires were conducted to determine their effects on soil and stream water chemistry. Stream water calcium concentrations increased in burned watersheds whereas soluble reactive phosphorus concentrations were not significantly different. Prescribed fires released calcium and raised soil pH and this may have resulted in the incorporation of phosphorus into insoluble forms. Stream monitoring data indicates water quality effects last for ~3 months. Prescribed fires did not significantly increase the amount of soluble reactive phosphorus in stream waters. However, additional research is needed to determine if prescribed fire increases erosion or movement of particulate P, particularly in areas with steep slopes.