bluuebunny/crossref_metadata_2025_split huggingface dataset:
Juan de Fuca subduction zone from a mixture of tomography and waveform modeling
Authors: Chu Risheng , Schmandt Brandon , Helmberger Don V. 
Published: January 2012

Seismic tomography images of the upper mantle structures beneath the Pacific Northwestern United States display a maze of high‐velocity anomalies, many of which produce distorted waveforms evident in the USArray observations indicative of the Juan de Fuca (JdF) slab. The inferred location of the slab agrees quite well with existing contour lines defining the slab's upper interface. Synthetic waveforms generated from a recent tomography image fit teleseismic travel times quite well and also some of the waveform distortions. Regional earthquake data, however, require substantial changes to the tomographic velocities. By modeling regional waveforms of the 2008 Nevada earthquake, we find that the uppermost mantle of the 1D reference model AK135, the reference velocity model used for most tomographic studies, is too fast for the western United States. Here, we replace AK135 with mT7, a modification of an older Basin‐and‐Range model T7. We present two hybrid velocity structures satisfying the waveform data based on modified tomographic images and conventional slab wisdom. We derive P and SH velocity structures down to 660 km along two cross sections through the JdF slab. Our results indicate that the JdF slab is subducted to a depth of 250 km beneath the Seattle region, and terminates at a shallower depth beneath Portland region of Oregon to the south. The slab is about 60 km thick and has a P velocity increase of 5% with respect to mT7. In order to fit waveform complexities of teleseismic Gulf of Mexico and South American events, a slab‐like high‐velocity anomaly with velocity increases of 3% for P and 7% for SH is inferred just above the 660 discontinuity beneath Nevada.
Histone H4 histidine phosphorylation: kinases, phosphatases, liver regeneration and cancer
Authors: Besant Paul G. , Attwood Paul V. 
Published: January 2012

Phosphorylation of histone H4 on one or both of its two histidine residues has been known to occur in liver cells for nearly 40 years and has been associated with proliferation of hepatocytes during regeneration of the liver following mechanical damage. More recently, large increases in histone H4 histidine kinase activity have been found to occur associated with proliferation and differentiation of liver progenitor cells following chemical damage that prevents hepatocyte proliferation. In addition, it has been shown this histone H4 histidine kinase activity is elevated nearly 100-fold in human foetal liver and several hundredfold in hepatocellular carcinoma tissue compared with normal adult liver. In the present paper, we review what is currently known about histone H4 histidine phosphorylation, the kinase(s) responsible and the phosphatases capable of catalysing its dephosphorylation, and briefly summarize the techniques used to detect and measure the histidine phosphorylation of histone H4 and the corresponding kinase activity.
Morphological and functional aspects of STIM1-dependent assembly and disassembly of store-operated calcium entry complexes
Authors: Shen Wei-Wei , Demaurex Nicolas 
Published: January 2012

The SOCE (store-operated Ca2+ entry) pathway is a central component of cell signalling that links the Ca2+-filling state of the ER (endoplasmic reticulum) to the activation of Ca2+-permeable channels at the PM (plasma membrane). SOCE channels maintain a high free Ca2+ concentration within the ER lumen required for the proper processing and folding of proteins, and fuel the long-term cellular Ca2+ signals that drive gene expression in immune cells. SOCE is initiated by the oligomerization on the membrane of the ER of STIMs (stromal interaction molecules) whose luminal EF-hand domain switches from globular to an extended conformation as soon as the free Ca2+ concentration within the ER lumen ([Ca2+]ER) decreases below basal levels of ~500 μM. The conformational changes induced by the unbinding of Ca2+ from the STIM1 luminal domain promote the formation of higher-order STIM1 oligomers that move towards the PM and exposes activating domains in STIM1 cytosolic tail that bind to Ca2+ channels of the Orai family at the PM and induce their activation. Both SOCE and STIM1 oligomerization are reversible events, but whether restoring normal [Ca2+]ER levels is sufficient to initiate the deoligomerization of STIM1 and to control the termination of SOCE is not known. The translocation of STIM1 towards the PM involves the formation of specialized compartments derived from the ER that we have characterized at the ultrastructural level and termed the pre-cortical ER, the cortical ER and the thin cortical ER. Pre-cortical ER structures are thin ER tubules enriched in STIM1 extending along microtubules and located deep inside cells. The cortical ER is located in the cell periphery in very close proximity (8–11 nm) to the plasma membrane. The thin cortical ER consists of thinner sections of the cortical ER enriched in STIM1 and devoid of chaperones that appear to be specialized ER compartments dedicated to Ca2+ signalling.
Rapid measurement of a high step microstructure with 90° steep sidewall
Authors: Ju Bing-Feng , Chen Yuan-Liu , Zhang Wei , Fang F. Z. 
Published: January 2012

A prototype STM system with high aspect ratio measurement capability is developed to fulfill accurate profile measurement of a high step microstructure with 90° steep sidewall. Distinguished from the traditional STM, the new system consists of a long range piezoelectric (PZT) actuator with full stroke of 60 μm as Z-direction servo scanner, a specially customized high aspect ratio STM probe with effective tip length of 300 μm, and an X-Y motorized driven stage for planar scanning. A tilt stage is used to adjust the probe-sample relative angle to compensate the evitable non-parallel effects. Based on the new STM system, sample-tilt-scanning methodology is proposed for eliminating the scanning blind region between the probe and the microstructure. A high step microstructure with height of 23 μm, 90° steep sidewall and width of 50μm has been successfully measured. The slope angle of the sidewall has been achieved to be 85° and the step height at the rising edge and the trench depth at the falling edge are both measured to be 22.96 μm. The whole measuring process only spent less than 10 min. It provides an effective and nondestructive solution for the measurement of high step or deep trench microstructures. In addition, this work also opens the way for further study on sidewall roughness and the tip-sample interaction at the edge of the sidewall, which are highly valuable for fabrication and quality control of high step microstructures.
A power pulsed low-pressure argon microwave plasma investigated by Thomson scattering: evidence for molecular assisted recombination
Authors: Hübner S , Palomares J M , Carbone E A D , van der Mullen J J A M 
Published: January 2012

Abstract
A squared-wave power pulsed low-pressure plasma is investigated by means of Thomson scattering. By this method the values of the electron density and temperature are obtained, directly. The plasma is created by a surfatron launcher in pure argon at gas pressures of 8–70 mbar. Features of the pulse rise and decay are studied with microsecond time resolution. During the pulse rise we observe initial high temperature values, while the density is still rising. At power switch-off we find decay times of the electron density that are smaller than what is expected on the basis of diffusion losses. This implies that the dominant decay mechanism in the studied pressure regime is provided by molecular assisted recombination.
Ants and the enigmatic Namibian fairy circles – cause and effect?
Authors: PICKER MIKE D. , ROSS‐GILLESPIE VERE , VLIEGHE KELLY , MOLL EUGENE 
Published: January 2012

1. Parts of the Namibian landscape show extensive surface perturbation in the form of long‐lived, yet dynamic ‘fairy circles'. While exerting profound ecological effects on 7.3% of the land surface, the origin and nature of these large bare discs embedded in an arid grassland matrix remains unresolved.2. We found no evidence to support the current hypothesis of a termite origin for fairy circles but instead observed a strong spatial association between fairy circles and large nests of the ant Black pugnacious ant Anoplolepis steingroeveri Forel, with much higher ant abundances on the circles compared with the matrix.3. Aggression trials showed that different colonies of A. steingroeveri were located on different circles, and that the species was polydomous.4. Fairy circles and Pogonomyrmex ant nests both have a bare disc surrounding the nest, are overdispersed (evenly spaced), and are associated with elevated soil moisture. Fairy circle soils exhibited a five‐fold increase in soil moisture when compared with the matrix.5. Senescent Stipagrostis obtusa (Delile) Nees seedlings were only observed on the circles and not in the matrix, and were found to have a reduction in both root length and number of roots.6. Anoplolepis steingroeveri excavated the root system of both S. obtusa seedlings on the disc and Stipagrostis ciliata (Desf.) de Winter grasses on the perimeter of the circles, where they tended honeydew‐secreting Meenoplidae bugs that fed on grass roots and culms. The bugs occurred almost exclusively on grasses associated with the circles. This ant–bug interaction is a possible mechanism for the observed reduction in root length and number of senescent grass seedlings on the circles.
Wet season range fidelity in a tropical migratory ungulate
Authors: Morrison Thomas A. , Bolger Douglas T. 
Published: January 2012

Summary1. In migratory populations, the degree of fidelity and dispersal among seasonal ranges is an important population process with consequences for demography, management, sensitivity to habitat change and adaptation to local environmental conditions.2. Characterizing patterns of range fidelity in ungulates, however, has remained challenging because of the difficulties of following large numbers of marked individuals across multiple migratory cycles and of identifying the appropriate scale of analysis.3. We examined fidelity to wet season (i.e. breeding) ranges in a recently declining population of wildebeest Connochaetes taurinus Burchell in northern Tanzania across 3 years. We used computer‐assisted photographic identification and capture–recapture to characterize return patterns to three wet season ranges that were ecologically discrete and topographically isolated from one another.4. Among 2557 uniquely identified adult wildebeest, we observed 150 recaptures across consecutive wet seasons. Between the two migratory subpopulations, the probability of remaining faithful to wet season areas ranged between 0·82 and 1·00. Animals from a non‐migratory segment of the population (near Lake Manyara National Park) were rarely observed in other wet season ranges, despite proximity to one of the migratory pathways.5. We found no effect of sex on an individuals’ probability of switching wet season ranges. However, the breeding status of females in year i had a strong influence on patterns of range selection in year i + 1, with surviving breeders over three times as likely to switch ranges as non‐breeders.6. Social‐group associations between pairs of recaptured animals were random with respect to an individual’s wet season range during the previous or forthcoming wet seasons, suggesting that an individual’s herd identity during the dry season does not predict wet season range selection.7. Examining fidelity and dispersal in terrestrial migrations improves our understanding of the constraints that migrants experience when they face rapid habitat changes or fluctuations in environmental conditions.
Edge effects and their influence on habitat suitability calculations: a continuous approach applied to birds of the Atlantic forest
Authors: Zurita Gustavo , Pe’er Guy , Bellocq M. Isabel , Hansbauer Miriam M. 
Published: January 2012

Summary1. The suitability of human‐modified habitats for native species and the response of species to habitat edges are two important ecological processes that affect species and communities in fragmented landscapes. However, field studies generally analyse these two processes separately. We extended a recently proposed continuous approach to link these two processes, using empirical data from birds of the Atlantic forest in Argentina, Paraguay and Brazil.2. We tested different models for describing the responses of birds (both forest and open‐habitat species) to the interior–exterior gradient within different edge types (ecotones). We used two types of data: the first originated from a large data set collected at regional scale using the point‐count method and the second originated from a detailed local telemetry study of three bird species.3. For both data sets, these models successfully described the responses to edges of the majority of species and assemblages and significantly influenced the calculated habitat suitability in both native and anthropogenic habitats. Edge effects were seen in the majority of species; however, the magnitude of these effects was influenced by the ecotone type. At the assemblage level, more species avoided edges in the ecotone with tree plantations compared with open habitats.4. The effect of edges on the calculated habitat suitability was either positive or negative, depending on the function that best described the response of the species to edges and whether they avoided edges or penetrated into the less‐preferred habitat. In general, forest species penetrated deeper into tree plantations but moved only short distances into open habitats.5. Synthesis and applications. Our results demonstrate the impact of edge effects on bird species and communities in fragmented landscapes. Furthermore, the differential penetration capacity of the native forest birds into anthropogenic habitats shows the importance of using a continuous approach to calculate habitat suitability; classic calculation (without considering the distance to the preferred habitat) is likely to bias the calculated suitability and permeability of the hostile matrix and affect our estimations of connectivity.
Automatic tracking of individual migrating cells using low‐magnification dark‐field microscopy
Authors: NENASHEVA T.A. , CARTER T. , MASHANOV G.I. 
Published: January 2012

SummaryMany fundamental biological processes, such as the search for food, immunological responses and wound healing, depend on cell migration. Video microscopy allows the magnitude and direction of cell migration to be documented. Here, we present a simple and inexpensive method for simultaneous tracking of hundreds of migrating cells over periods of several days. Low‐magnification dark‐field microscopy was used to visualize individual cells whereas time‐lapse video images were acquired by computer for future analysis. We employed an automated tracking algorithm to identify individual cells on each video image allowing migration paths to be tracked using a nearest neighbour algorithm. To test the method, we followed the time‐course of migration of 3T3 fibroblasts, endothelial cells and individual amoeba in the absence of any chemical stimulus gradient. All cell types showed a ‘random walk’ behaviour in which mean squared displacement in position increased linearly with time. We defined a ‘migration coefficient’ (Dmig), analogous to a diffusion coefficient, which gave an estimate of cell migration rate. Dmig depended on cell type and temperature. When amoebas were made to undergo chemotaxis, the cells no longer followed a random walk but instead moved at a near constant velocity (Vav) towards the chemotactic stimulus.
Assessment of the impact of resistant and susceptible canola on Plasmodiophora brassicae inoculum potential
Authors: Hwang S. F. , Ahmed H. U. , Zhou Q. , Strelkov S. E. , Gossen B. D. , Peng G. , Turnbull G. D. 
Published: January 2012

The impact on clubroot severity of growing susceptible canola or mixtures of resistant and susceptible canola genotypes was examined. Bioassays revealed greater clubroot severity and incidence, and reduced plant height, where 100% of a susceptible cultivar had been grown. A higher proportion of susceptible plants within a resistant canola crop increased root hair and secondary infections. Regression analysis of root hair infection and the amount of Plasmodiophora brassicae DNA (as determined by quantitative PCR) revealed strong linear relationships between the two parameters. The linear relationships between root hair infection and P. brassicae DNA were stronger for the resistant cultivar than for the susceptible cultivar when regression analysis was conducted by cultivar over the sampling dates. In conclusion, the cropping of a resistant cultivar reduced clubroot severity, while the presence of susceptible volunteer canola increased inoculum potential. Quantitative PCR was a reliable tool for the quantification of root hair infection.
Microbiota and dietary interactions – an update to the hygiene hypothesis?
Authors: Frei R. , Lauener R. P. , Crameri R. , O'Mahony L. 
Published: January 2012

AbstractThe dramatic increase in the incidence and severity of allergy and asthma has been proposed to be linked with an altered exposure to, and colonization by, micro‐organisms, particularly early in life. However, other lifestyle factors such as diet and physical activity are also thought to be important, and it is likely that multiple environmental factors with currently unrecognized interactions contribute to the atopic state. This review will focus on the potential role of microbial metabolites in immunoregulatory functions and highlights the known molecular mechanisms, which may mediate the interactions between diet, microbiota, and protection from allergy and asthma.
Size scaling and stiffness of avian primary feathers: implications for the flight of Mesozoic birds
Authors: WANG X. , NUDDS R. L. , PALMER C. , DYKE G. J. 
Published: January 2012

AbstractThe primary feathers of birds are subject to cyclical forces in flight causing their shafts (rachises) to bend. The amount the feathers deflect during flight is dependent upon the flexural stiffness of the rachises. By quantifying scaling relationships between body mass and feather linear dimensions in a large data set of living birds, we show that both feather length and feather diameter scale much closer to predictions for geometric similarity than they do to elastic similarity. Scaling allometry also indicates that the primary feathers of larger birds are relatively shorter and their rachises relatively narrower, compared to those of smaller birds. Two‐point bending tests indicated that larger birds have more flexible feathers than smaller species. Discriminant functional analyses (DFA) showed that body mass, primary feather length and rachis diameter can be used to differentiate between different magnitudes of feather bending stiffness, with primary feather length explaining 63% of variance in rachis stiffness. Adding fossil measurement data to our DFA showed thatArchaeopteryxandConfuciusornisdo not overlap with extant birds. This strongly suggests that the bending stiffness of their primary feathers was different to extant birds and provides further evidence for distinctive flight styles and likely limited flight ability inArchaeopteryxandConfuciusornis.
Recurrent endocrine mucin‐producing sweat gland carcinoma in the eyelid
Authors: Koike Tomoyuki , Mikami Taro , Maegawa Jiro , Iwai Toshinori , Wada Hidefumi , Yamanaka Shoji 
Published: January 2012

ABSTRACTEndocrine mucin‐producing sweat gland carcinoma (EMPSGC) has recently been recognised as a low‐grade carcinoma that almost always occurs on the eyelid. This carcinoma is very rare, with only 20 cases (including the present one) having been reported in the literature. EMPSGC is frequently found in association with invasive mucinous carcinoma. While EMPSGC treatments consist of a complete surgical removal, there has been no consensus regarding the surgical margin. Therefore, reports on surgical management of EMPSGC may potentially provide important therapeutic information. Here, we present a case of a 74‐year‐old man with EMPSGC of the eyelid that repeatedly recurred despite surgical treatments at another institution. After referral to our department, the patient underwent tumour excision. However, the specimen revealed a positive surgical margin and thus, he subsequently underwent a wider excision. There has been no sign of tumour recurrence or metastasis 6 months after his last operation. This article reviews the current literature and discusses the surgical management of EMPSGC.
Isovolaemic hemodilution with gelatin and hydroxyethylstarch 130/0.42: effects on hemostasis in piglets
Authors: Witt Lars , Osthaus Wilhelm Alexander , Jahn Wiebke , Rahe‐Meyer Niels , Hanke Alexander , Schmidt Florian , Boehne Martin , Sümpelmann Robert 
Published: January 2012

SummaryObjectives:  Artificial colloids, frequently used to prevent hemorrhagic shock in children, impair blood coagulation. To determine the impact of acute isovolaemic hemodilution with artificial colloids on clot formation, we conducted an experimental study in a pediatric animal model.Methods:  Fifteen piglets underwent hemorrhage by withdrawing 40 ml·kg−1 of blood volume in steps of 10 ml·kg−1 each within 1 hour. After each withdrawal, the blood loss was randomly compensated by administering 4% gelatin (GEL) or hydroxylethyl starch 130/0.42 (HES) in a ratio of 1 : 1, or isotonic crystalloid solution (ICS) in a ratio of 1 : 4 for isovolaemic hemodilution. Quality of clot formation and platelet function was measured using Thrombelastometry (ROTEM®) and Multiple electrode impedance aggregometry (Multiplate®) after 10, 20, and 40 ml·kg−1 blood replacement.Results:  Moderate hemodilution (10–20 ml·kg−1 blood replacement) caused no significant differences among groups (e.g. INTEM®‐MCF after 20 ml·kg−1 blood replacement (ICS vs GEL vs HES, P > 0.05). Profound hemodilution with 40 ml·kg−1 blood replacement showed a significant difference between ICS and both colloids (P < 0.05), but no significant differences between GEL and HES.Conclusions:  Impairment of clot formation by moderate isovolaemic hemodilution did not significantly differ between ICS, GEL, and HES. Profound hemodilution of more than 50% of the estimated blood volume with GEL and HES caused significant impairment of clot formation in comparison to ICS and has to be considered when using high amounts of these synthetic colloids.
EXAM SCHEDULING AND STUDENT PERFORMANCE
Authors: Di Pietro Giorgio 
Published: January 2012

ABSTRACTThis paper uses data from a single School of a UK university to estimate the impact of a switch from end‐of‐semester to end‐of‐year final exams on student performance. The identification strategy exploits the fact that while the timing of final exams changed, the timing of mid‐term exams remained the same. Estimates are based on a difference‐in‐differences methodology that compares final and mid‐term exam scores after the switch, with final and mid‐term exam scores before the switch. The empirical findings suggest that the shift of final exams to the end of the academic year had a negative effect on student achievement. Many changes in higher education are often done on the basis of financial, administrative or ideological considerations, underestimating the magnitude of their effect on student learning and student performance.