bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solution structure of the PWWP domain of the hepatoma‐derived growth factor family
Authors: Nameki Nobukazu , Tochio Naoya , Koshiba Seizo , Inoue Makoto , Yabuki Takashi , Aoki Masaaki , Seki Eiko , Matsuda Takayoshi , Fujikura Yukiko , Saito Miyuki , Ikari Masaomi , Watanabe Megumi , Terada Takaho , Shirouzu Mikako , Yoshida Mayumi , Hirota Hiroshi , Tanaka Akiko , Hayashizaki Yoshihide , Güntert Peter , Kigawa Takanori , Yokoyama Shigeyuki 
Published: February 2005

AbstractAmong the many PWWP‐containing proteins, the largest group of homologous proteins is related to hepatoma‐derived growth factor (HDGF). Within a well‐conserved region at the extreme N‐terminus, HDGF and five HDGF‐related proteins (HRPs) always have a PWWP domain, which is a module found in many chromatin‐associated proteins. In this study, we determined the solution structure of the PWWP domain of HDGF‐related protein‐3 (HRP‐3) by NMR spectroscopy. The structure consists of a five‐stranded β‐barrel with a PWWP‐specific long loop connecting β2 and β3 (PR‐loop), followed by a helical region including two α‐helices. Its structure was found to have a characteristic solvent‐exposed hydrophobic cavity, which is composed of an abundance of aromatic residues in the β1/β2 loop (β‐β arch) and the β3/β4 loop. A similar ligand binding cavity occurs at the corresponding position in the Tudor, chromo, and MBT domains, which have structural and probable evolutionary relationships with PWWP domains. These findings suggest that the PWWP domains of the HDGF family bind to some component of chromatin via the cavity.
Learning effectiveness in a Web‐based virtual learning environment: a learner control perspective
Authors: Chou Shih‐Wei , Liu Chien‐Hung 
Published: February 2005

AbstractWeb‐based technology has a dramatic impact on learning and teaching. A framework that delineates the relationships between learner control and learning effectiveness is absent. This study aims to fill this void. Our work focuses on the effectiveness of a technology‐mediated virtual learning environment (TVLE) in the context of basic information technology skills training. Grounded in the technology‐mediated learning literature, this study presents a framework that addresses the relationship between the learner control and learning effectiveness, which contains four categories: learning achievement, self‐efficacy, satisfaction, and learning climate. In order to compare the learning effectiveness under traditional classroom and TVLE, we conducted a field experiment. Data were collected from a junior high school of Taiwan. A total of 210 usable responses were analysed. We identified four results from this study. (1) Students in the TVLE environment achieve better learning performance than their counterparts in the traditional environment; (2) Students in the TVLE environment report higher levels of computer self‐efficacy than their counterparts in the traditional environment; (3) Students in the TVLE environment report higher levels of satisfaction than students in the traditional environment; and (4) Students in the TVLE environment report higher levels of learning climate than their counterparts in the traditional environment. The implications of this study are discussed, and further research directions are proposed.
Sequence stratigraphy of the Upper Oligocene–Lower Miocene of eastern Jylland, Denmark: role of structural relief and variable sediment supply in controlling sequence development
Authors: RASMUSSEN ERIK S. , DYBKJÆR KAREN 
Published: February 2005

AbstractThe Upper Oligocene–Lower Miocene succession in eastern Jylland can be subdivided into three sequences (A–C from older to younger) deposited on and around the Ringkøbing‐Fyn High. The development of the sequences reflects a complex interaction between eustatic sea‐level changes, physiography and variable sediment supply. Superimposed on this, frequent storms promoted longshore sediment transport and the development of spit systems adjacent to structural highs. As a consequence, sequence boundaries and flooding surfaces are not always expressed as portrayed in conventional sequence models; sequence boundaries or flooding surfaces may only be marked by subtle changes in depositional environment that can only be revealed by careful integration of sedimentological observations with palynological data. The influence of the topography resulted in the development of brackish water basins that were sufficiently large to permit the deposition of hummocky cross‐stratified sands with muds. These deposits are overlain by clean hummocky and swaley cross‐stratified sands that were deposited in a fully marine, high‐energy environment. This evolution from mud‐rich, storm‐influenced sediments to sand‐dominated shoreface sediments resulted from a rise in sea level and was not the result of shoreface progradation and downstepping during a sea level fall. In addition to the topographic control on sequence development, sediment supply to the study area changed significantly during the deposition of the three sequences. Initially the basin was sediment‐starved, favouring the formation of glaucony‐rich sediments. The sediment input gradually increased and the influence of structural highs and lows became less significant with time. Consequently, both sequence boundaries and flooding surfaces are characterized by more conventional features in the younger part of the succession, where a basinward displacement of the shoreline resulted in thick lowstand delta deposits.
Wavy lamination in a mixed sand and gravel foreshore facies of the Pleistocene Hosoya Sandstone, Aichi, central Japan
Authors: HIROKI YOSHIHISA , TERASAKA TAKASHI 
Published: February 2005

AbstractAlthough sandy foreshore facies are generally characterized by parallel lamination, wavy lamination is predominant in the mixed sand and gravel foreshore facies of the Pleistocene Hosoya Sandstone, which crops out along the Pacific coast of the Atsumi Peninsula, Aichi, central Japan. The foreshore facies consists of three sedimentary subfacies; interbeds of gravel and parallel laminated sand of the lower foreshore facies, parallel laminated fine to medium sand beds containing scattered pebbles and cobbles of the middle foreshore facies, and wavy laminated fine to medium sand beds containing scattered pebbles and cobbles of the upper foreshore facies. A lack of erosional surfaces in the middle foreshore facies indicates the continuous accumulation of sand in flat beds under upper plane bed flow. The wavy laminated sands of the upper foreshore facies exhibit erosional surfaces indicative of repeated deposition and erosion. The erosional surfaces are undulatory, with depressions (10 cm wide and 3 cm deep) that contain scattered pebbles and cobbles. These depressions reflect backwash erosion of sand around and below the pebbles and cobbles. Sand draping over the undulating erosional surfaces forms the wavy lamination. The wavy laminated sand with scattered pebbles and cobbles is a key facies of an upper foreshore or swash zone, and is a good sea‐level marker.
Microbial‐foraminiferal episodes in the Early Aptian of the southern Tethyan margin: ecological significance and possible relation to oceanic anoxic event 1a
Authors: IMMENHAUSER A. , HILLGÄRTNER H. , VAN BENTUM E. 
Published: February 2005

AbstractTwo regionally significant microbial‐foraminiferal episodes (∼150 kyr each) occur within the Early Aptian shallow marine platform in Oman and throughout eastern Arabia. The stratigraphically lower of these two intervals is characterized by isolated or coalescent domes that share similarities with modern, open‐marine stromatolites from the Exuma Cays, Bahamas. The upper interval is predominantly built by a problematic Lithocodium/Bacinella consortium in buildup and massive boundstone facies. Based on high‐resolution chemostratigraphy, these shoalwater intervals are coeval with oceanic anoxic event 1a (OAE1a; Livello Selli). Field evidence demonstrates that the buildup episodes alternate with stratigraphic intervals dominated by rudist bivalves. This biotic pattern is also recognized in other coeval Tethyan sections and is perhaps a characteristic shoalwater expression of the OAE1a. The short‐lived regional expansions of this microbial‐foraminiferal out‐of‐balance facies cannot be explained by local environmental factors (salinity and oxygen level) alone and the buildup consortia do not occupy stressed refugia in the absence of grazing metazoans. Judging from recent analogues, the main fossil groups, i.e. microbial assemblages, macroalgae, larger sessile foraminifera, and rudist bivalves, all favoured elevated trophic levels but with different tolerance limits. The implication of this is that the influence of palaeofertility events, possibly related to OAE1a, on carbonate platform community structures must be investigated. The observations made in these coastal sections are a significant first step for the improved understanding of the Early Aptian period of biotic, oceanic and climatic change.
Holocene millennial to centennial carbonate cyclicity recorded in slope sediments of the Great Bahama Bank and its climatic implications
Authors: ROTH SVEN , REIJMER JOHN J. G. 
Published: February 2005

AbstractA 38 m long sediment core (MD992201) retrieved from a water depth of 290 m from the leeward margin of the Great Bahama Bank (GBB; 25°53·49′N, 79°16·34′W) has been investigated for changes in aragonite content. The core covers the Mid to Late Holocene (the past 7230 yr). Sediment lightness (L*‐values) was used as a proxy for aragonite content, based on a high linear correlation (R = 0·93) between the X‐ray diffraction derived aragonite content and L*‐values. The resulting time resolution of the L*‐values derived aragonite content ranges from 1 yr at the base of the core to 4 yr at the top. Detailed time series analysis using Monte Carlo Singular Spectrum Analysis and spectral analysis (Lomb–Scargle Fourier transform) identifies the presence of seven signals with varying amplitudes and wavelengths that could be traced throughout the past 5500 yr. During the first ∼1600 yr of sedimentation the aragonite record is dominated by the initial flooding of the flat‐topped GBB. Superimposed on a multimillennial signal, related to Holocene sea‐level changes, a millennial‐scale fluctuation and five quasi‐periodic oscillations were detected (∼1·3–2 kyr, ∼500–600 yr, ∼380 yr, ∼260 yr, ∼200 yr and ∼100 yr period). Comparisons with other proxies (e.g. tree ring‐Δ14C, 10Be and δ18O in ice cores) provides information on the origin and dynamics of the individual signals. The analysis shows that the ∼200 yr and ∼100 yr signals can be attributed to solar forcing. The ∼260 yr, ∼380 yr and the ∼500–600 yr quasi‐periodic signals are found to be of climatic origin, whereas the millennial scale fluctuations remain enigmatic, although solar forcing mechanisms seem likely. The data show that variability of solar output as well as past oceanographic and atmospheric changes have modulated the Mid to Late Holocene climate, which in turn controlled sediment input variations found in the Holocene wedge leeward of the GBB. Although these periplatform sediments have a rather uniform appearance, they still contain a large variety of subtle sedimentary variations.
Dewatering effects on the erodibility of newly deposited cohesive beds by unidirectional currents
Authors: GÓMEZ EDUARDO A. , AMOS CARL L. 
Published: February 2005

AbstractA series of laboratory experiments on cohesive sediments under inorganic conditions was undertaken in order to evaluate the impact of fluid bed shear stress on the build‐up of bed resistance to erosion with time. The importance of small pressures due to flowing water to increase bed strength is presented. It is also shown that the susceptibility of a cohesive bed to changes in its erodibility is related to deposited bed thickness due to sediment disturbance caused by dewatering from the consolidating bed. Laboratory experiments that use beds deposited from suspension should thus report the thickness of the bed prior to resuspension.
Deformation structures and an alteration zone linked to deposition of volcanogenic sulphate in an ancient playa (Oligocene of Nebraska, USA)
Authors: LOOPE DAVID B. , MASON JOSEPH A. , BAO HUIMING , KETTLER RICHARD M. , ZANNER C. WILLIAM 
Published: February 2005

AbstractHistoric, sulphur‐rich volcanic eruptions have altered global climate for as much as five years, and much larger events are known from the geologic record. At Scotts Bluff, Nebraska, Early Oligocene strata of the lower Arikaree Group contain a tephra bed with abundant calcite pseudomorphs after gypsum. Previous work has shown sulphate from the pseudomorphs in this tephra bears a high17O anomaly indicative of oxidation of sulphur gases by ozone or hydrogen peroxide in the atmosphere. Possible sources of the tephra were caldera eruptions at about 28 Ma in the San Juan volcanic field of south‐western Colorado (∼500 km SW of the study site) and the eastern Great Basin (∼1000 km WSW). The present sedimentological study shows that tephra and volcanogenic sulphate were deposited and preserved within a small, surface‐discharging playa that developed on the irregular upper surface of aeolian siltstones of the subjacent White River Group. Sulphate solutions (including perhaps sulphuric acid) percolated downward within the vadose zone, dissolving early formed smectite cement within underlying volcaniclastic sandstones, reddening these rocks along an irregular alteration front. Preserved fine‐scale stratification within the sandstones precludes the possibility that reddening took place during pedogenesis. Displacive growth of gypsum at the playa centre folded tephra beds and forced tephra into underlying sandstones, forming elongate cones. The large mass fraction of gypsum (now replaced by calcite) in the playa sediments suggests a huge, long‐distance delivery of sulphate aerosols. Some of the sulphate and tephra may have come from the same eruption, or the fine‐grained tephra may simply have aided preservation of dry‐fog sulphate derived from an unrelated, effusive eruption of lava.
Ecological and Phylogenetic Effects on Song Sharing in Songbirds
Authors: Handley Heather G. , Nelson Douglas A. 
Published: February 2005

AbstractAs a consequence of vocal learning, the songs of male songbirds often vary geographically. We examined three proximate hypotheses that predict variation in the incidence of local song sharing among species: the annual cycle, breeding season duration, and epiphenomenon hypotheses. To test these hypotheses, we compiled data from the literature on local song sharing, annual cycle, breeding location isophane (an index of breeding season duration), repertoire size, and phylogenetic relationships of 65 populations in the family Fringillidae. Mapping characters on the phylogenetic tree revealed that local song sharing, migratory status, and breeding location isophane were randomly distributed on the phylogeny. Breeding isophane and migratory status were themselves correlated and had significant effects on the probability of sharing local songs. As predicted by the annual cycle and breeding season duration hypotheses, males in sedentary populations and populations breeding at low isophanes were more likely to share local songs. In subsets of the data, the annual cycle hypothesis received more support than did the breeding season duration hypothesis. Neither hypothesis explained more than 17% of the variation in the incidence of song sharing, and we suggest that detailed information on song function, male dispersal, and constraints on the timing of song learning will be needed to better predict the occurrence of local song sharing.
Shoal Choice in Swordtails when Preferences Conflict
Authors: Wong Bob B. M. , Rosenthal Gil G. 
Published: February 2005

AbstractIndividuals obtain a range of benefits from aggregating with others. Evidence suggests that group size and the phenotypic characteristics of potential group mates are both important attributes influencing the grouping decisions of prospective group members. Their interaction, however, remains poorly understood. Here we investigate, in a series of dichotomous choice experiments, what happens when a preference with respect to group size is pitted against a preference for assorting on the basis of body size in swordtail fish. When controlled for body size, we found that swordtails preferred to associate with a larger shoal. When controlled for group size, we found that swordtails preferred to associate with similar‐sized fish. However, when offered the choice between a single size‐matched shoaling partner and four dissimilar‐sized shoal mates, we found that females associated randomly. Our results suggest that, depending on context, group size and body size may be equally important in guiding the aggregating decisions of swordtails. Future studies will likely offer valuable insights into shoaling behaviour by considering how, and under what circumstances, different grouping preferences might be prioritized.
Differential Behavioural Effects of Silent Bared Teeth Display and Relaxed Open Mouth Display in Chimpanzees (Pan troglodytes)
Authors: Waller Bridget M. , Dunbar Robin I. M. 
Published: February 2005

AbstractThis study examines the behavioural consequences of the silent bared teeth display (SBT) and the relaxed open mouth display (ROM) in the chimpanzee, and discusses functional similarities with smiling and laughing (respectively) in humans. Rates of affinitive behaviour increase (in relation to baseline levels) following SBT, suggesting that SBT is a signal of affinity. ROM is observed primarily during play, and dyadic play bouts are significantly longer when ROM is bidirectional, indicating that it may be a signal of play. Rates of affinitive behaviour also increased after ROM, suggesting that both displays may have a similar ultimate (evolutionary) function – social bonding; this could explain convergence of the two displays in humans.
Vigilance during Preening in Coots Fulica atra
Authors: Randler Christoph 
Published: February 2005

AbstractIn birds, vigilance during feeding is usually linked with (1) the many‐eyes‐hypothesis, (2) the dilution effect, and (3) the intraspecific scramble competition hypothesis. To exclude competition for resources as a driving force in vigilance research into activities other than feeding is necessary. Additionally, variables such as nearest neighbour distance and position within a flock are supposed to influence vigilance and vigilance of singletons should be compared with vigilance of flock members. I studied vigilance during preening in Eurasian Coots (Fulica atra) and counted the number of scans per minute. A total number of 117 coots were sampled with 16 of them preening alone. Coots preening alone showed a significantly higher scan rate. I found a significant negative correlation between vigilance and flock size while nearest neighbour distance correlated positively with vigilance. Further, vigilance was higher in individuals at the edge. A general linear model using nearest neighbour distance and flock size within 10 m as covariates also revealed a significant influence of flock size but not of nearest neighbour distance. The centre‐edge effect still remained significant. These results indicate that flock size is the most influential predictor of vigilance in preening coots, followed by spatial organization. However, using nearest neighbour distance instead of flock size also produced a significant model as did the flock size measurement within a radius of 20 m. As scramble competition could be ruled out, the flock size effect may be indeed related to predation.
Predicting Herbivore Feeding Times
Authors: Jeschke Jonathan M. , Tollrian Ralph 
Published: February 2005

AbstractAn understanding of animal time budgets is crucial to behavioural biology. Although many studies have analysed time budgets of individual species, only a few have made interspecific comparisons. Here we take an interspecific look at one part of the time budget, feeding time. We hypothesize that feeding time can be predicted by the amount of time an animal needs to reach satiation. This time should be equal to the ratio of handling time to digestion time. For 19 herbivorous species from insects to mammals, we calculate this ratio and compare it to the observed feeding time. The mean difference between calculated and observed values is small (a half hour per 24 h‐day), indicating that herbivore feeding times can often be approximated by the ratio of handling time to digestion time. We make three points concerning the time allocated to feeding in herbivores based on this interspecific comparison. First, our analysis suggests that herbivores often feed to satiation, which could mean that they are often released from time constraints. It is also possible, however, that while herbivores have enough time to reach satiation, they do not necessarily have sufficient time to choose the most desirable diet. Wilson's principle of stringency theoretically supports the former interpretation. It suggests that animals experience periods in their life in which they are time‐constrained but that these periods are the exception rather than the rule. Most optimal foraging studies have assumed the opposite. The second point of this paper is therefore a recommendation: to consider the possibility that animals may often be released from time constraints. The third and final point is that feeding time is independent of body mass in our analysis. This is because handling time scales with body mass according to a parameter that is similar to the one for digestion time, and feeding time can be approximated by the ratio of handling time to digestion time.
Wall Lizards Modulate Refuge Use through Continuous Assessment of Predation Risk Level
Authors: Martín José , López Pilar 
Published: February 2005

AbstractPrey species might use several possible ways to assess predation risk when encountering a predator. Animals may consider the risk level estimated in a first encounter to remain unchanged across subsequent encounters (fixed risk response), or they may update and change their responses across encounters in accordance with short‐term changes in risk levels (flexible risk response). We examined in the field how wall lizards assess risk level by analyzing time spent in refuges after simulated predator attacks. We first examined how risk was assessed when multiple consecutive sources of risk were present simultaneously. The results suggest that wall lizards assess risk based on multiple cues, such as approach speed, directness, and persistence (measured as the distance of the predator to their refuge after an attack). When risk was high lizards remained longer in their refuges. The first decision to appear partly from the refuge depended on both approach speed and persistence, whereas the decision to emerge completely depended only on persistence and not on approach speed. This suggests that wall lizards update information on predator threat and adjusted their emergence accordingly. In a second experiment, we analyzed how short‐term changes in risk level of successive attacks affected refuge use. Successive emergence times varied as a function of current risk level of each repeated attack, independently of the risk level of previous attacks. This indicated that lizards could track short‐term changes in risk level through time and modify their initial responses when required. Fine adjustments of refuge use may help lizards to minimize costs of refuge use in unfavorable and variable environments where antipredatory responses are costly.