bluuebunny/crossref_metadata_2025 huggingface dataset:
Giant tunneling magnetoresistance in epitaxial Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions by half-metallicity of Co2MnSi and coherent tunneling
Authors: Liu Hong-xi , Honda Yusuke , Taira Tomoyuki , Matsuda Ken-ichi , Arita Masashi , Uemura Tetsuya , Yamamoto Masafumi
Published: September 2012

Giant tunnel magnetoresistance (TMR) ratios of up to 1995% at 4.2 K and up to 354% at 290 K were obtained for epitaxial Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions (MTJs) featuring a reduced lattice mismatch in the MTJ trilayer by introducing a thin Co2MnSi lower electrode deposited on a Co50Fe50 buffer layer. The obtained giant TMR ratios can be explained by the enhanced contribution of coherent tunneling originating from the increased misfit dislocation spacing at the lower and upper interfaces with a MgO barrier along with the half-metallicity of Co2MnSi electrodes.
Polariton emission characteristics of a modulation-doped multiquantum-well microcavity diode
Authors: Das Ayan , Xiao Bo , Bhowmick Sishir , Bhattacharya Pallab
Published: September 2012

The role of polariton-electron scattering on the performance characteristics of an electrically injected GaAs-based quantum well (QW) microcavity diode in the strong coupling regime has been investigated. An electron gas is introduced in the quantum wells by modulation doping with silicon dopants. It is observed that polariton-electron scattering suppresses the relaxation bottleneck in the lower polariton branch. However, it is not adequate to produce a degenerate coherent condensate at k∥ ∼ 0 and coherent emission.
Studies on nanosecond pulsed atmospheric pressure discharge with particle-in-cell Monte Carlo collision simulation
Authors: Yang Chenguang , Duan Lian , Xu Yongyue , Wang Xinbing , Zuo Duluo
Published: September 2012

Nanosecond pulsed atmospheric pressure discharge becomes an active research topic because of its promising prospect of applications in many areas. To understand its dynamics, the discharge process was studied by one-dimensional implicit particle-in-cell Monte Carlo collision (PIC-MCC) simulation coupled with a particle renormalization algorithm, in which multiple electron Monte Carlo collisions per step were considered to improve the computation efficiency. In the simulation, the effects of discharge conditions such as plateau voltage, pulse rise time, and initial charged particle density were investigated. It is found that the plateau voltage in the pulse waveform is a major factor controlling the final charged particle density in the plasma bulk, and the built-up time and steady thickness of cathode sheath are proportional to the pulse rise time, whereas reversely proportional to the initial charged particle density.
Role of nucleation sites on the formation of nanoporous Ge
Authors: Yates B. R. , Darby B. L. , Elliman R. G. , Jones K. S.
Published: September 2012

The role of nucleation sites on the formation of nanoporous Ge was investigated. Three Ge films with different spherical or columnar pore morphologies to act as inherent nucleation sites were sputtered on (001) Ge. Samples were implanted 90° from incidence at 300 keV with fluences ranging from 3.0 × 1015 to 3.0 × 1016 Ge+/cm2. Electron microscopy investigations revealed varying thresholds for nanoporous Ge formation and exhibited a stark difference in the evolution of the Ge layers based on the microstructure of the initial film. The results suggest that the presence of inherent nucleation sites significantly alters the onset and evolution of nanoporous Ge.
Evidence for a Size Underestimation of Upright Faces
Authors: Araragi Yukyu , Aotani Takehiro , Kitaoka Akiyoshi
Published: September 2012

We quantitatively examined the difference in perceived size between upright and inverted faces using the method of constant stimuli. The stimuli included eight face images modified from two cartoon faces produced by Kitaoka (2007, http://www.psy.ritsumei.ac.jp/∼akitaoka/kao-e.html and 2008, Cognitive Psychology5 177–185) and six photographic faces, including a photographic face used by Thompson (2010, http://illusioncontest.neuralcorrelate.com/2010/the-fat-face-thin-fft-illusion/ ). Experiment 1 showed that an upright face and outline were perceived to be significantly smaller than an inverted face and outline, respectively. Moreover, the amount of the size underestimation in the face stimulus condition was significantly larger than that in the outline stimulus condition. Experiment 2 showed that an upright face was perceived to be significantly smaller than 90° and 270° rotated faces, whereas an inverted face was not perceived to be significantly larger than a 90° or 270° rotated face. Experiment 3 showed that upright faces were perceived to be significantly smaller than upright and inverted outlines, whereas inverted faces were not perceived to be significantly larger than upright or inverted outlines. Experiments 4 and 5 showed that upright photographic faces were also perceived to be significantly smaller than inverted photographic faces. These results provide quantitative evidence for a size underestimation of upright faces.
Height Perception Influenced by Texture Gradient
Authors: Tozawa Junko
Published: September 2012

Three experiments were carried out to examine whether a texture gradient influences perception of relative object height. Previous research implicated texture cues in judgments of object width, but similar influences have not been demonstrated for relative height. In this study, I evaluate a hypothesis that the projective ratio of the number of texture elements covered by the objects combined with the ratio of the retinal object heights determines percepts of relative object height. Density of texture background was varied: four density conditions ranged from no-texture to very dense texture. In experiments 1 and 2, participants judged the height of comparison bar compared to the standard bar positioned on no-texture or textured backgrounds. Results showed relative height judgments differed with texture manipulations, consistent with predictions from a hypothesised combination of the number of texture elements with retinal height (experiment 1), or partially consistent with this hypothesis (experiment 2). In experiment 2, variations in the position of a comparison object showed that comparisons located far from the horizon were judged more poorly than in other positions. In experiment 3 I examined distance perception; relative distance judgments were found to be also affected by textured backgrounds. Results are discussed in terms of Gibson's relational theory and distance calibration theory.
The Minimal Time Required to Process Visual Information in Visual Search Tasks Measured by Using Gaze-Contingent Visual Masking
Authors: Seya Yasuhiro , Watanabe Katsumi
Published: September 2012

To estimate the minimal time required to process visual information (ie “effective acquisition time”) during a visual search task, we used a gaze-contingent visual masking method. In the experiment, an opaque mask that restricted the central vision was presented at a current gaze position. We manipulated a temporal delay from a gaze shift to mask movement. Participants were asked to search for a target letter (T) among distractor letters (L)s as quickly as possible under various delays. The results showed that the reaction times and search rate decreased when the delay was increased. When the delay was longer than 50 ms, the reaction times and search rate reached a plateau. These results indicate that the effective acquisition time during the visual search task used in the study is equal to or less than 50 ms. The present study indicates that the gaze-contingent visual masking method used is useful for revealing the effective acquisition time.
Evidence for Crossmodal Interactions across Depth on Target Localisation Performance in a Spatial Array
Authors: Chan Jason S , Maguinness Corrina , Lisiecka Danuta , Setti Annalisa , Newell Fiona N
Published: September 2012

Auditory stimuli are known to improve visual target recognition and detection when both are presented in the same spatial location. However, most studies have focused on crossmodal spatial congruency along the horizontal plane and the effects of audio-visual spatial congruency in depth (ie along the depth axis) are relatively less well understood. In the following experiments we presented a visual (face) or auditory (voice) target stimulus in a location on a spatial array which was either spatially congruent or incongruent in depth (ie positioned directly in front or behind) with a crossmodal stimulus. The participant's task was to determine whether a visual (experiments 1 and 3) or auditory (experiment 2) target was located in the foreground or background of this array. We found that both visual and auditory targets were less accurately located when crossmodal stimuli were presented from different, compared to congruent, locations in depth. Moreover, this effect was particularly found for visual targets located in the periphery, although spatial incongruency affected the location of auditory targets across both locations. The relative distance of the array to the observer did not seem to modulate this congruency effect (experiment 3). Our results add to the growing evidence for multisensory influences on search performance and extend these findings to the localisation of targets in the depth plane.
Subjective Contours along Truncated Letters
Authors: Gillam Barbara , Vecellio Elia
Published: September 2012

The truncation of upper-case words can result in a subjective contour along the truncated ends of the letters. We explored this effect in two experiments designed to tease apart the processes responsible: in particular, the possible role of letter recognition. Such a role would indicate an unprecedented involvement of “high-level vision” in the genesis of subjective contours. In experiment 1, we confirmed the basic effect of word truncation in eliciting a subjective contour, using only letters where truncation does not eliminate any critical features. In experiment 2, we showed that the effect is not confined to words/letters but is equally strong for controlled non-letter stimuli that, like words, have many forms that have an inflection or an intersection near the centre. Truncation at one end then introduces proportional imbalance between upper and lower sections of the figures. We conclude from the two experiments that part of the effect is due to vertical shortening per se and the rest to the proportional imbalance introduced by the truncation. The effect of proportional imbalance, a novel determinant of subjective contours, may result from experience with letters, although the effect is not “high level” in requiring the recognition of specific letters.
Impact of radial external magnetic field on plasma deformation during contact opening in SF6 circuit breakers
Authors: Abbasi V , Gholami A , Niayesh K
Published: September 2012

A three-dimensional (3D) transient model is developed to investigate plasma current deformation driven by internal and external magnetic fields and their influences on arc stability in a circuit breaker. The 3D distribution of electric current density is obtained by solving the current continuity equation along with the generalized Ohm's law in the presence of an external magnetic field, while the magnetic field induced by the current flowing through the arc column is calculated by the magnetic vector potential equation. The applied external field imposes a rotational electromagnetic force on the arc and influences the plasma current deformation, which is discussed in this paper. In SF6 circuit breakers when gas interacts with the arc column, the fundamental equations such as Ampere's law, Ohm's law, turbulence model, transport equations of mass, momentum, and energy of plasma flow have to be coupled for analysing the phenomenon. The coupled interactions between the arc and the plasma flow are described within the framework of magnetohydrodynamic equations in conjunction with a K–ε turbulence model. Simulations are focused on sausage and kink instabilities in the plasma (these phenomena are related to the electromagnetic field distribution and define the plasma deformations). The 3D simulation reveals the relation between plasma current deformation and instability phenomena, which affects the arc stability during the operation. Plasma current deformation is a consequence of coupling between electromagnetic forces (resulting from internal and radial external magnetic fields) and the plasma flow that are described in the simulations.
The bubble to jetting transition mechanism of plasmas in NaNO3 solutions sustained by pulsed power
Authors: Hsieh An-hsuan , Chang Hung-wen , Hsu Cheng-che
Published: September 2012

Plasmas in NaNO3 solutions sustained by pulsed power with T
on = 10–500 µs are studied. With an applied voltage equal to or lower than 100 V, the bubble mode is observed. In this mode, bubbles, a few hundred μm in diameter, are formed and detached continuously at the electrode surface because of the buoyant force. An increase in the applied voltage to 125 V results in a bubble to jetting transition. When this transition occurs, bubbles with diameters smaller than 100 µm are formed and are rapidly jetted away continuously. The examination of various conditions shows that the transition occurs when the power and energy input simultaneously exceed critical values 4.4 × 10−3 ± 6 × 10−4 J and 45 ± 5 W, respectively, within T
on. Given the electrode surface area, this critical power is equivalent to a heat flux of 229 ± 25 MW m−2, which is close to the heat flux required, 223 MW m−2, for the occurrence of explosive vaporization reported in the literature. Such an observation strongly supports the hypothesis that the bubble to jetting transition is induced by the electrothermal effect.
The nuclear membrane leukotriene synthetic complex is a signal integrator and transducer
Authors: Bair Angela M. , Turman Melissa V. , Vaine Christine A. , Panettieri Reynold A. , Soberman Roy J.
Published: September 2012

Leukotrienes (LTs) are lipid-signaling molecules derived from arachidonic acid (AA) that initiate and amplify inflammation. To initiate LT formation, the 5-lipoxygenase (5-LO) enzyme translocates to nuclear membranes, where it associates with its scaffold protein, 5-lipoxygenase–activating protein (FLAP), to form the core of the multiprotein LT synthetic complex. FLAP is considered to function by binding free AA and facilitating its use as a substrate by 5-LO to form the initial LT, LTA4. We used a combination of fluorescence lifetime imaging microscopy, cell biology, and biochemistry to identify discrete AA-dependent and AA-independent steps that occur on nuclear membranes to control the assembly of the LT synthetic complex in polymorphonuclear leukocytes. The association of AA with FLAP changes the configuration of the scaffold protein, enhances recruitment of membrane-associated 5-LO to form complexes with FLAP, and controls the closeness of this association. Granulocyte monocyte colony–stimulating factor provides a second AA-independent signal that controls the closeness of 5-LO and FLAP within complexes but not the number of complexes that are assembled. Our results demonstrate that the LT synthetic complex is a signal integrator that transduces extracellular signals to modulate the interaction of 5-LO and FLAP.
Displacement of basolateral Bazooka/PAR-3 by regulated transport and dispersion during epithelial polarization inDrosophila
Authors: McKinley R. F. Andrew , Harris Tony J. C.
Published: September 2012

Polarity landmarks guide epithelial development. In the early Drosophila ectoderm, the scaffold protein Bazooka (Drosophila PAR-3) forms apicolateral landmarks to direct adherens junction assembly. However, it is unclear how Bazooka becomes polarized. We report two mechanisms acting in concert to displace Bazooka from the basolateral membrane. As cells form during cellularization, basally localized Bazooka undergoes basal-to-apical transport. Bazooka requires its three postsynaptic density 95, discs large, zonula occludens-1 (PDZ) domains to engage the transport mechanism, but with the PDZ domains deleted, basolateral displacement still occurs by gastrulation. Basolateral PAR-1 activity appears to act redundantly with the transport mechanism. Knockdown of PAR-1 sporadically destabilizes cellularization furrows, but basolateral displacement of Bazooka still occurs by gastrulation. In contrast, basolateral Bazooka displacement is blocked with disruption of both the transport mechanism and phosphorylation by PAR-1. Thus Bazooka is polarized through a combination of transport and PAR-1–induced dispersion from basolateral membranes. Our work complements recent findings in Caenorhabditis elegans and thus suggests the coupling of transport and dispersion is a common protein polarization strategy.
Diagnosis and Management of Osteoporosis
Authors: Patel Ishita , Zaro Sanjedah
Published: September 2012

Osteoporosis is a condition in which the bone matrix is compromised, leading to thin, fragile bones that fracture easily. It has a significant socio-economic impact, both from the cost of treating such fractures and for the individual going through what is often a traumatic experience with a lengthy recovery. Therefore, as clinicians our focus should be on the early identification of disease and instigation of treatment. This article focuses on the diagnosis and management of osteoporosis, summarizing current guidance along with providing practical tips on how to manage affected patients in our consultation rooms.
Influence of Cooking Formulation on Flavor and Hydrophilic Oxygen Radical Absorption Capacity Values of Whole Grain Colored Rice
Authors: Bett‐Garber Karen L. , Lea Jeanne M. , Watson Michael A. , Champagne Elaine T.
Published: September 2012

Whole grain rice is rich in healthful polyphenolic compounds that can impart undesirable flavors. Rice is typically prepared with water and sometimes salt, oil, or both, which can influence flavor. This research examines the influences of cooking whole grain rice with salt, oil, or both on flavor and antioxidant capacity. Nine commercial rice samples (three brown, three red, and three black or purple) were cooked with water only, added salt (0.5%), oil (1.575% v/w), or salt with oil (same concentrations). Flavor was measured with descriptive flavor analysis, and antioxidant capacity was measured by the hydrophilic oxygen radical absorption capacity (H‐ORAC) method. The addition of salt and salt with oil significantly reduced bitter, waterlike/metallic, and astringent flavors, whereas corn/popcorn/buttery flavor was increased. Cooking formulation significantly affected more flavor attributes in black/purple and brown bran samples than in the red bran samples. Salt, oil, or both can be added to rice at cooking to modify taste with only slight effects on antioxidant benefits. Bran color significantly influences many flavor attributes as well as impacting H‐ORAC values.
First Report of Garlic Rust Caused by Puccinia allii on Allium sativum in Minnesota
Authors: Szabo L. J. , Mollov D. S. , Rosen C.
Published: September 2012

High-quality garlic is an emerging crop grown in Minnesota for local markets, community supported agriculture, and select restaurants. In July 2010, Allium sativum cv. German Extra Hardy Porcelain plants showing foliar symptoms typical of rust infection were brought to the Plant Disease Clinic at the University of Minnesota by a commercial grower from Fillmore County, Minnesota. Infected leaves showed circular to oblong lesions (1 to 3 mm long), which ranged in color from yellow-orange (uredinia) to black (telia). Urediniospores collected from uredinia were globoid to ellipsoid, yellowish in color, and measured 18 ± 1 × 30 ± 2 μm with a wall thickness of 2.4 ± 0.5 μm. Teliospores were two celled, 18 ± 3 × 47 ± 10 μm, with a projected cross-sectional area (1) of 826 ± 87 μm2; cell walls were smooth, brown, 1.6 ± 0.3 μm (proximal cell) to 2.1 ± 0.5 μm (distal cell) thick, and 4.2 ± 0.8 μm at the apex. The pathogen was identified as Puccinia allii (2) and a sample was deposited in the U.S. National Fungus Collection (BPI 884132). DNA was extracted from infected leaf tissue and the nuclear ribosomal internal transcribed spacer region (ITS) and 5′ end of the large subunit (LS) was amplified and sequenced as described by Anikster et al. (1). The 1,257-bp sequence from the sample collected in Minnesota (GenBank Accession No. JX402206) was identical to ITS/LS sequence of a sample of P. allii collected from garlic in California (GenBank Accession No. AF511077), with the exception that MN sequence contained nine “A”s rather than 10 in the hyper-variable area at the 3′ end of the ITS region. P. allii has been shown to be a species complex comprising at least two different types, “leek type” and “garlic type” (1). Based on the ITS sequence and the projected cross-sectional area of the teliospores, the sample of P. allii from MN is consistent with the garlic type. Garlic rust occurred in localized foci late in the growing season and therefore did not cause significant loss to the 2010 crop. Reoccurrence of garlic rust was not reported in either 2011 or 2012 growing seasons in Minnesota. P. allii all but eliminated commercial garlic production in California in the late 1990s (1) and has the potential to cause significant negative impact to the emerging garlic crop in Minnesota. However, the epidemiology of garlic rust in the northern U.S. is not well understood and therefore predicting the risk of the Minnesota garlic crop to rust is difficult.

References: (1) Y. Anikster et al. Phytopathology 94:569, 2004. (2) L. J. Szabo et al, Rust. Pages 41-44 in: Compendium of Onion and Garlic Diseases and Pests, Second Edition. H. F. Schwartz and S. K. Mohan, eds. APS Press, St. Paul, 2008.
Editorial
Authors: Stuart Trevor
Published: September 2012

I would like to introduce myself as the Editor of
Biographical Memoirs
since 1 January 2012, having taken over from Professor Tom Meade, to whom I express my sincere thanks for his four years as Editor. Moreover there are other changes to the Editorial Board, as it is in the process of being expanded to include a still wider panel of research expertise.
Dramatic intraspecific differences in migratory routes, stopover sites and wintering areas, revealed using light-level geolocators
Authors: Delmore Kira E. , Fox James W. , Irwin Darren E.
Published: September 2012

Migratory divides are contact zones between breeding populations that use divergent migratory routes and have been described in a variety of species. These divides are of major importance to evolution, ecology and conservation but have been identified using limited band recovery data and/or indirect methods. Data from band recoveries and mitochondrial haplotypes suggested that inland and coastal Swainson's thrushes (Catharus ustulatus) form a migratory divide in western North America. We attached light-level geolocators to birds at the edges of this contact zone to provide, to our knowledge, the first direct test of a putative divide using data from individual birds over the entire annual cycle. Coastal thrushes migrated along the west coast to Mexico, Guatemala and Honduras. Some of these birds used multiple wintering sites. Inland thrushes migrated across the Rocky Mountains, through central North America to Colombia and Venezuela. These birds migrated longer distances than coastal birds and performed a loop migration, navigating over the Gulf of Mexico in autumn and around this barrier in spring. These findings support the suggestion that divergent migratory behaviour could contribute to reproductive isolation between migrants, advance our understanding of their non-breeding ecology, and are integral to development of detailed conservation strategies for this group.
Vampire squid: detritivores in the oxygen minimum zone
Authors: Hoving Hendrik J. T. , Robison Bruce H.
Published: September 2012

Vampire squid (Vampyroteuthis infernalis) are considered phylogenetic relics with cephalopod features of both octopods and squids. They lack feeding tentacles, but in addition to their eight arms, they have two retractile filaments, the exact functions of which have puzzled scientists for years. We present the results of investigations on the feeding ecology and behaviour ofVampyroteuthis, which include extensivein situ, deep-sea video recordings from MBARI's remotely operated vehicles (ROVs), laboratory feeding experiments, diet studies and morphological examinations of the retractile filaments, the arm suckers and cirri. Vampire squid were found to feed on detrital matter of various sizes, from small particles to larger marine aggregates. Ingested items included the remains of gelatinous zooplankton, discarded larvacean houses, crustacean remains, diatoms and faecal pellets. Both ROV observations and laboratory experiments led to the conclusion that vampire squid use their retractile filaments for the capture of food, supporting the hypothesis that the filaments are homologous to cephalopod arms.Vampyroteuthis' feeding behaviour is unlike any other cephalopod, and reveals a unique adaptation that allows these animals to spend most of their life at depths where oxygen concentrations are very low, but where predators are few and typical cephalopod food is scarce.
Sex-ratio adjustment in response to local mate competition is achieved through an alteration of egg size in a haplodiploid spider mite
Authors: Macke Emilie , Magalhães Sara , Bach Fabien , Olivieri Isabelle
Published: September 2012

Sex-ratio adjustments are commonly observed in haplodiploid species. However, the underlying proximate mechanisms remain elusive. We investigated these mechanisms in
Tetranychus urticae
, a haplodiploid spider mite known to adjust sex ratio in response to the level of local mate competition (LMC). In this species, egg size determines fertilization probability, with larger eggs being more likely to be fertilized, and thus become female. We explored the hypothesis that sex-ratio adjustment is achieved through adjustment of egg size. By using spider mites from a large population, we found that females produced not only a higher proportion of daughters under high levels of LMC, but also larger eggs. Moreover, in populations experimentally evolving under varying levels of LMC, both the proportion of females and the egg size increased with LMC intensity. These results suggest that sex-ratio adjustment in spider mites is mediated by egg size, although the causal relationship remains to be tested.
Reduction of polyhedrin mRNA and protein expression levels in Sf9 and Hi5 cell lines, but not in Sf21 cells, infected with Autographa californica multiple nucleopolyhedrovirus fp25k mutants
Authors: Cheng Xin-Hua , Hillman Christopher C. , Zhang Chuan-Xi , Cheng Xiao-Wen
Published: September 2012

During cell infection, the fp25k gene of baculoviruses frequently mutates, producing the few polyhedra (FP) per cell phenotype with reduced polyhedrin (polh) expression levels compared with wild-type baculoviruses. Here we report that the fp25k gene of the model baculovirus, Autographa californica multiple nucleopolyhedrovirus (AcMNPV), contains two hypermutable seven-adenine (A7) mononucleotide repeats (MNRs) that were mutated to A8 MNRs and a TTAA site that had host DNA insertions, producing fp25k mutants during Sf21 cell infection. The FP phenotype in Sf9 and Hi5 cells was more pronounced than in Sf21 cells. AcMNPV fp25k mutants produced similar levels of polyhedra or enhanced GFP, which were both under the control of the AcMNPV polh promoter for expression, in Sf21 cells but lower levels in Sf9 and Hi5 cells compared with AcMNPV with an intact fp25k gene. This correlated with the polh mRNA levels detected in each cell line. The majority of Sf21 cells infected with fp25 mutants showed high polh promoter-mediated GFP expression levels. Two cell lines subcloned from Sf21 cells that were infected with fp25k mutants showed different GFP expression levels. Furthermore, a small proportion of Hi5 cells infected with fp25k mutants showed higher production of polyhedra and GFP expression than the rest, and the latter was not correlated with increased m.o.i. Therefore, these data suggest that AcMNPV polh promoter-mediated gene expression activities differ in the three cell lines and are influenced by different cells within the cell line.
Tropism, compartmentalization and retention of banana bunchy top virus (Nanoviridae) in the aphid vector Pentalonia nigronervosa
Authors: Watanabe Shizu , Bressan Alberto
Published: September 2012

Plant viruses of the families Luteoviridae and Geminiviridae rely on hemipteran vectors for the infection of their hosts. Several lines of evidence have revealed that these viruses are transmitted by competent vectors in a circulative manner, involving entry into the vector’s body and the crossing of epithelial tissues forming the alimentary tract and the salivary glands. Similar to luteovirids and geminiviruses, a third family of plant viruses, the family Nanoviridae, have also been reported to be transmitted by aphids in a circulative manner. However, there is limited direct evidence of a possible path of translocation through the aphid vectors. Here, we used time-course experiments and transmission assays coupled with real-time PCR and immunofluorescence assays on dissected tissues to examine the translocation, compartmentalization and retention of banana bunchy top virus (BBTV) into the aphid vector Pentalonia nigronervosa. Our results indicate that BBTV translocates rapidly through the aphid vector; it is internalized into the anterior midgut in which it accumulates and is retained at concentrations higher than either the haemolymph or the principal salivary glands. Despite the large increase in viral concentration, we have failed to detect BBTV transcripts with RT-PCR. When tissues were not permeabilized, BBTV localized as distinct puncta in the proximity of the basal surface of the cells forming the anterior midgut and principal salivary glands, suggesting an on-going process of virion escape and internalization, respectively. Interestingly, we document that those organs can have direct contact within the aphid body, suggesting a possible haemolymph-independent translocation path.
ΔNp63α represses anti-proliferative genes via H2A.Z deposition
Authors: Gallant-Behm Corrie L. , Ramsey Matthew R. , Bensard Claire L. , Nojek Ignacio , Tran Jack , Liu Minghua , Ellisen Leif W. , Espinosa Joaquín M.
Published: September 2012

ΔNp63α is a member of the p53 family of transcription factors that functions as an oncogene in squamous cell carcinomas (SCCs). Because ΔNp63α and p53 bind virtually identical DNA sequence motifs, it has been proposed that ΔNp63α functions as a dominant-negative inhibitor of p53 to promote proliferation and block apoptosis. However, most SCCs concurrently overexpress ΔNp63α and inactivate p53, suggesting the autonomous action of these oncogenic events. Here we report the discovery of a novel mechanism of transcriptional repression by ΔNp63α that reconciles these observations. We found that although both proteins bind the same genomic sites, they regulate largely nonoverlapping gene sets. Upon activation, p53 binds all enhancers regardless of ΔNp63α status but fails to transactivate genes repressed by ΔNp63α. We found that ΔNp63α associates with the SRCAP chromatin regulatory complex involved in H2A/H2A.Z exchange and mediates H2A.Z deposition at its target loci. Interestingly, knockdown of SRCAP subunits or H2A.Z leads to specific induction of ΔNp63α-repressed genes. We identified SAMD9L as a key anti-proliferative gene repressed by ΔNp63α and H2A.Z whose depletion suffices to reverse the arrest phenotype caused by ΔNp63α knockdown. Collectively, these results illuminate a molecular pathway contributing to the autonomous oncogenic effects of ΔNp63α.
Water distribution at local and landscape scales affects tree utilization by elephants in Chobe National Park, Botswana
Authors: Fullman Timothy Jon , Child Brian
Published: September 2012

African elephant distribution and impacts are influenced by water availability. This study investigates the formation of piospheres – gradients of vegetation degradation with increasing proximity to water – at local and landscape scales in Chobe National Park, Botswana. Thirty‐four plots record elephant impact on trees in a transect extending over 60 km from the Chobe River, differentiating between debarking and browsing on branches. Elephant utilization exhibits local patterns nested within a landscape‐level context. At a local scale, branch herbivory decreases with distance from water, while debarking first decreases and then increases again. At a landscape scale, regression and canonical correlation analyses show decreasing debarking with distance from the river. Surprisingly, branch herbivory increases with distance from river, except within the first 10 km where previous studies have focused. Elephant impact on vegetation is both more complex and extensive than previously assumed. Piosphere predictions are upheld at the local scale, with utilization decreasing with distance from water. This does not hold at the landscape scale, however, likely due to seasonal shifts in elephant distribution, diet and the presence of water in ephemeral pans. These findings have important implications for elephant management and emphasize the importance of looking across scales when assessing elephant impact.
MiR‐150 is associated with poor prognosis in esophageal squamous cell carcinoma via targeting the EMT inducer ZEB1
Authors: Yokobori Takehiko , Suzuki Shigemasa , Tanaka Naritaka , Inose Takanori , Sohda Makoto , Sano Akihiko , Sakai Makoto , Nakajima Masanobu , Miyazaki Tatsuya , Kato Hiroyuki , Kuwano Hiroyuki
Published: September 2012

The association of microRNAs (miRs) with cancer progression has been established in many cancers including esophageal squamous cell carcinoma (ESCC). A public microarray database showed that the expression of miR‐150 was lower in ESCC than in normal esophageal mucosa. Here, we focused on ZEB1, epithelial‐mesenchymal‐transition (EMT)‐inducer, as a target gene of miR‐150 based on in silico predictions. The purpose of this study was to clarify the clinicopathological significance of miR‐150 in ESCC, and to investigate miR‐150′s EMT‐regulatory ability. Quantitative RT‐PCR was used to evaluate miR‐150 expression in 108 curative resected ESCC samples to determine the clinicopathological significance. Moreover, we examined the in vitro and in vivo function of miR‐150 via degradation of ZEB1. MiR‐150 expression was significantly lower in cancer tissues compared to adjacent non‐cancerous tissues (P < 0.001). Low expression of miR‐150 in ESCC contributed to malignant potential, such as tumor depth, lymph node metastasis, lymphatic invasion, venous invasion, clinical staging, and poor prognosis (P < 0.05). In vitro assays showed that EMT‐inducer‐ZEB1 is a new direct target of miR‐150. Moreover, miR‐150 induced MET‐like changes in TE‐8 cells through ZEB1 degradation (e.g., E‐cadherin expression, vimentin repression, epithelial morphology, and suppression of migration ability), and significantly inhibited tumorigenicity and tumor growth in a mouse xenograft model. Analysis of the regulation of ZEB1 by miR‐150 could provide new insights into preventing metastasis and also suggests novel targeted therapeutic strategies in ESCC. (Cancer Sci 2013; 104: 48–54)
The impact of dis‐/reconnection of laser microgrooved and machined implant abutments on soft‐ and hard‐tissue healing
Authors: Iglhaut Gerhard , Becker Kathrin , Golubovic Vladimir , Schliephake Henning , Mihatovic Ilja
Published: September 2012

Objectives

To (i) investigate the influence of different extensions of a laser microgrooved abutment zone on connective tissue attachment and (ii) assess the impact of a repeated abutment dis‐/reconnection on soft‐ and hard‐tissue healing.

Materials and Methods

Titanium implants were inserted epicrestally in the lower jaws of six dogs. Healing abutments with either partially (LP) or completely (LC) laser microgrooved margins or machined surface margins (M) were randomly allocated either to a single (1×)/repeated (2×) dis‐/reconnection at 4 and 6 weeks (test), respectively, or left undisturbed (control). At 6 and 8 weeks, histomorphometrical (e.g. most coronal level of bone in contact with the implant [CBI], subepithelial connective tissue attachment [STC]) and immunohistochemical (Collagen Type‐I [CI]) parameters were assessed.

Results

At control sites, LP/LC groups revealed lower mean CBL (8 weeks, 0.95 ± 0.51 vs. 0.54 ± 0.63 vs. 1.66 ± 1.26 mm), higher mean STC (8 weeks, 82.58 ± 24.32% vs. 96.37 ± 5.12% vs. 54.17 ± 8.09%), but comparable CI antigen reactivity. A repeated abutment manipulation was associated with increased mean CBL (8 weeks, 1.53 ± 1.09 vs. 0.94 ± 0.17 vs. 1.06 ± 0.34 mm), decreased STC (8 weeks, 57.34 ± 43.06% vs. 13.26 ± 19.04% vs. 37.76 ± 37.08%) and CI values.

Conclusions

It was concluded that (i) LC>LP abutments enhanced subepithelial connective tissue attachment and preserved crestal bone levels, (ii) repeated abutment dis‐/reconnection during the initial healing phase (4–6 weeks) may be associated with increased soft‐ and hard‐tissue changes and (iii) LP and LC should be considered using a one abutment, one time approach.
Characterising the impacts of emerging energy development on wildlife, with an eye towards mitigation
Authors: Northrup Joseph M. , Wittemyer George
Published: September 2012

Global demand for energy is projected to increase by 40% in the next 20 years, and largely will be met with alternative and unconventional sources. Development of these resources causes novel disturbances that strongly impact terrestrial ecosystems and wildlife. To effectively position ecologists to address this prevalent conservation challenge, we reviewed the literature on the ecological ramifications of this dominant driver of global land‐use change, consolidated results for its mitigation and highlighted knowledge gaps. Impacts varied widely, underscoring the importance of area and species‐specific studies. The most commonly reported impacts included behavioural responses and direct mortality. Examinations of mitigation were limited, but common easements included (1) reduction of the development footprint and human activity, (2) maintenance of undeveloped, ‘refuge’ habitat and (3) alteration of activity during sensitive periods. Problematically, the literature was primarily retrospective, focused on few species, countries, and ecoregions, and fraught with generalisations from weak inference. We advocate future studies take a comprehensive approach incorporating a mechanistic understanding of the interplay between development‐caused impacts and species ecology that will enable effective mitigation. Key areas for future research vital to securing a sustainable energy future in the face of development‐related global change are outlined.
Effects of predation on real‐time host–parasite coevolutionary dynamics
Authors: Friman Ville‐Petri , Buckling Angus
Published: September 2012

The impact of community complexity on pairwise coevolutionary dynamics is theoretically dependent on the extent to which species evolve generalised or specialised adaptations to the multiple species they interact with. Here, we show that the bacteria Pseudomonas fluorescens diversifies into defence specialists, when coevolved simultaneously with a virus and a predatory protist, as a result of fitness trade‐offs between defences against the two enemies. Strong bacteria–virus pairwise coevolution persisted, despite strong protist‐imposed selection. However, the arms race dynamic (escalation of host resistance and parasite infectivity ranges) associated with bacteria–virus coevolution broke down to a greater extent in the presence of the protist, presumably through the elevated genetic and demographic costs of increased bacteria resistance ranges. These findings suggest that strong pairwise coevolution can persist even in complex communities, when conflicting selection leads to evolutionary diversification of different defence strategies.
Finding the optimal vertical distribution: behavioural responses of Daphnia pulicaria to gradients of environmental factors and the presence of fish
Authors: LARSSON PETTER , LAMPERT WINFRIED
Published: September 2012

1. The vertical distribution of zooplankton results from active habitat choice aiming to optimise fitness gain in a system of trade‐offs.

2. Using large, controlled indoor mesocosms (Plön Plankton Towers), we monitored the behavioural response of Daphnia pulicaria to vertical gradients of temperature, food, oxygen and light, in the presence and absence of fish predation.

3. In the absence of fish, Daphnia distributed as predicted by an ideal ‘free distribution with costs’. If the food was distributed homogeneously, they stayed in the warm epilimnion, while they balanced their time dwelling in epi‐ and hypolimnion if the food was concentrated in a deep‐water maximum.

4. However, oxygen depletion in the hypolimnion, representing an additional cost, prevented Daphnia from completely exploiting the hypolimnetic food maximum. Consequently, the proportion dwelling in the hypolimnion was larger if oxygen was not limiting.

5. Fish predation had an overwhelming effect, driving Daphnia into the hypolimnion under all experimental conditions. If permitted by oxygen availability, Daphnia used the whole hypolimnion, but oxygen depletion reduced their possible habitat to the upper hypolimnion with oxygen concentrations above c. 0.7 mg L−1. As fish were less tolerant of low oxygen, the layer below the thermocline formed a predation refuge for Daphnia.
Long‐term Celecoxib can Prevent the Progression of Persistent Gastric Intestinal Metaplasia After H. pylori Eradication
Authors: Sheu Bor‐Shyang , Tsai Yu‐Ching , Wu Chung‐Tai , Chang Wei‐Lun , Cheng Hsiu‐Chi , Yang Hsiao‐Bai
Published: September 2012

Background and Aim

Intestinal metaplasia (IM) has overexpressions of COX‐2. Short‐term 8‐week celecoxib, a selective COX‐2 inhibitor, exerts a preliminary hint to improve regression in part for persistent IM after Helicobacter pylori eradication. This study further validated whether or not a prolonged duration of celecoxib of up to 1 year can be safe and effective.

Methods

One hundred and forty patients, with persistent IM after H. pylori eradication for 1 year, were included with half of them receiving celecoxib 200 mg/day for 12 months and the other half serving as controls. Each patient received serial checkups of blood creatinine levels every 4 months. After the 1‐year follow‐up, panendoscopy was repeated to assess the IM regression. The serial gastric specimens, taken before and after celecoxib therapy, were immunochemically stained for COX‐2.

Results

The intention‐to‐treat (ITT) and per‐protocol (PP) analyses to the rates of IM regression were higher in the celecoxib group than in the controls (ITT: 44.3% [31/70] vs 14.3% [10/70], p < .001; and PP: 51.7% [31/60] vs 16.1% [10/62], p < .001). All enrolled patients had no renal impairment during follow‐up. Even in the patients without IM regression, the mean IM scores and COX‐2 expressions were significantly more decreased in the celecoxib group than in the controls (p < .005).

Conclusion

One year 200‐mg celecoxib daily be safely administered to improve the regression or prevent the progression of persistent IM after H. pylori eradication.
Mapping rainbow trout immune genes involved in inflammation reveals conserved blocks of immune genes in teleosts
Authors: Phillips R. B. , Ventura A. B. , DeKoning J. J. , Nichols K. M.
Published: September 2012

We report the genetic map location of 14 genes involved in the inflammatory response to salmonid bacterial and viral pathogens, which brings the total number of immune genes mapped in rainbow trout (RT, Oncorhynchus mykiss) to 61. These genes were mapped as candidate genes that may be involved in resistance to bacterial kidney disease, as well as candidates for known QTL for resistance to infectious hematopoietic necrosis virus, infectious pancreatic necrosis virus and Ceratomyxa shasta. These QTL map to one or more of the linkage groups containing immune genes. The combined analysis of these linkage results and those of previously mapped immune genes in RT shows that many immune genes are found in syntenic blocks of genes that have been retained in teleosts despite species divergence and genome duplication events.
Assessing model fit in phylogeographical investigations: an example from the North American sandbar willow Salix melanopsis
Authors: Tsai Yi‐Hsin Erica , Carstens Bryan C.
Published: September 2012

Aim

Coalescent models enable the direct estimation of parameters with clear biological relevance (i.e. divergence time, migration rate and rate of expansion), but they have typically been applied to phylogeographical research without a priori assessment of their fit to the empirical system. Here we explore the extent to which phylogeographical inference can be misled by evaluating the fit of several population genetic models to empirical data collected from the sandbar willow, Salix melanopsis.

Location

The Pacific Northwest mesic forest of North America.

Methods

We collected sequence data from five loci in 145 individuals. We assessed model fit in: (1) models delimiting previously proposed races within S. melanopsis; (2) historical biogeographical models, each describing the timing and pattern of diversification; and (3) coalescent models that correspond to those implemented in popular software packages such as IMa, lamarc, and Migrate‐n.

Results

We found little evidence for previous hypotheses of cryptic races delimited by habitat type (mesic, lowland or subalpine); rather, our results suggested that these variants originated from the same source population. Historical biogeographical models demonstrate that S. melanopsis has recently expanded from a single refugial population, probably located in the northern Rocky Mountains. An analysis using approximate Bayesian computation indicated that the single population expansion model implemented in lamarc is a better fit to the data than multi‐population models incorporating migration and/or divergence as implemented in Migrate‐n and IMa, suggesting that the parameters estimated from the latter are potentially misleading for this system.

Main conclusions

Our research highlights the importance of assessing model fit in addition to estimating parameters to understand evolutionary processes. Taken together, they allow us to infer the historical demography of S. melanopsis in a manner that is not biased by previous work in the system.