bluuebunny/crossref_metadata_2025 huggingface dataset:
Typicality of Inanimate Category Exemplars in Aphasia Treatment: Further Evidence for Semantic Complexity
Authors: Kiran Swathi
Published: August 2008

Purpose

The typicality treatment approach on improving naming was investigated within 2 inanimate categories (furnitureandclothing) using a single-subject experimental design across participants and behaviors in 5 patients with aphasia.

Method

Participants received a semantic feature treatment to improve naming of either typical or atypical items within semantic categories, whereas generalization was tested to untrained items of the category. The order of typicality and category trained was counterbalanced across participants.

Results

Results indicated that 2 out of 4 patients trained on naming of atypical examples demonstrated generalization to naming untrained typical examples. One patient showed trends toward generalization but did not achieve criterion. Furthermore, all 4 patients trained on typical examples demonstrated no generalized naming to untrained atypical examples within the category. Also, analysis of errors indicated an evolution of errors as a result of treatment, from those with no apparent relationship to the target to primarily semantic and phonemic paraphasias.

Conclusion

These results extend our previous findings (S. Kiran & C. K. Thompson, 2003a) to patients with nonfluent aphasia and to inanimate categories such asfurnitureandclothing. Additionally, the results provide support for the claim that training atypical examples is a more efficient method of facilitating generalization to untrained items within a category than training typical examples (S. Kiran, 2007).
Maternal Epistemological Perspectives and Variations in Mental State Talk
Authors: Hutchins Tiffany L. , Bond Lynne A. , Silliman Elaine R. , Bryant Judith B.
Published: August 2008

Purpose

This study examined how complexity of maternal epistemological beliefs predicted mothers' and children’s talk about the mind.

Method

Twenty-eight mothers of 5- to 10-year-olds completed a measure of receptive vocabulary, and mothers and children participated in a storytelling task specifically designed to elicit talk about the mind. Their use of mental state terms to encode pragmatic functions and mothers' epistemologies were assessed and compared.

Results

Maternal mental state talk and amount of talk increased with epistemological complexity. With the number of utterances held constant, mothers with simple, dualistic perspectives of knowledge used mental states more often to direct interaction; mothers with more complex epistemologies used mental states more often to encourage child reflection. Mothers with the less complex perspective underperformed on the receptive vocabulary measure in comparison to others. Children’s amount of talk and use of a variety of mental state terms also increased with maternal epistemological complexity. The amount of talk and mental state terms produced by mothers and children frequently persisted after the effects of maternal receptive vocabulary were removed.

Conclusions

Maternal epistemologies predict several qualities of mothers' and children’s mental state talk that may contribute to children’s developing theory of mind.
Reading Achievement Growth in Children With Language Impairments
Authors: Catts Hugh W. , Bridges Mindy Sittner , Little Todd D. , Tomblin J. Bruce
Published: August 2008

Purpose

This study examined the reading achievement growth of children with language impairments (LI) across the school grades. The authors sought to determine whether children with LI demonstrate a delayed, deficit, or cumulative pattern of reading achievement growth when compared with children with typical language (TL).

Method

A group of 225 children with LI and a group of 379 children with TL were identified in kindergarten and were administered multiple measures of word recognition and reading comprehension in 2nd, 4th, 8th, and 10th grades.

Results

Confirmatory factor analyses indicated that the constructs of word recognition and reading comprehension were invariant across grades and groups of children with LI and TL. Further analyses indicated that a multiple group latent growth curve analysis was appropriate. This analysis showed that children with LI differed significantly from children with TL in initial level (2nd grade) of word recognition and reading comprehension, but they did not differ significantly in the shape of their growth trajectories.

Conclusion

These results are consistent with a deficit model of reading growth in children with LI. Findings are discussed in terms of implications for early identification.
Charge generation layer in stacked organic light-emitting devices
Authors: Fung M. K. , Lau K. M. , Lai S. L. , Law C. W. , Chan M. Y. , Lee C. S. , Lee S. T.
Published: August 2008

Three types of organic-based connection units were examined for use in stacked or tandem organic light-emitting devices, which include (i) Mg-doped tris(8-hydrooxyquinoline) aluminum(III) (Alq3)∕4,4′,4″-tris{N,-(3-methylphenyl)-N-phenylamino}-triphenylamine (m-MTDATA), (ii) Alq3/tetrafluorotetracyanoquinodimethane (F4-TCNQ)-doped m-MTDATA, and (iii) Mg-doped Alq3/F4-TCNQ-doped m-MTDATA. Device (iii) shows the highest current efficiency and the differences in device performance can be correlated with the electronic structure of the connection unit and its interface with the neighboring active layers. The working mechanisms of the connection-unit works are discussed in terms of band bending and charge carrier density. The electronic structures of the interface between layers in a connection unit are of particular importance to the device performance. Dopings of Mg in Alq3 and F4-TCNQ in m-MTDATA led to bipolar heterojunction. Removal of either the n-type or the p-type dopants suppresses the band bending and the formation of space charge regions. The charge density accumulated at this interface estimated from Poisson’s equation is 1018∕cm3, which is respectively 12 and 6 orders of magnitude higher than that in the Mg:Alq3/m-MTDATA and Alq3/F4-TCNQ:m-MTDATA connection units. Based on these results, the critical roles of dopants in an efficient connecting unit for stacked organic light-emitting diodes are elucidated.
Physical mechanisms of hydrogen-enhanced onset of epitaxial growth of silicon by plasma-enhanced chemical vapor deposition
Authors: Tan X. , Yang G. W.
Published: August 2008

We have theoretically performed the detailed physical process and the temperature dependence of the hydrogen-enhanced amorphous-to-crystalline transformation of silicon upon plasma-enhanced chemical vapor deposition (PECVD) using the kinetic Monte Carlo simulations. It is found that the epitaxial silicon can be obtained at very low temperatures (T⩾450K) upon PECVD with H2 dilution. Our simulations have profound implications for closing the gap between atomic-scale and macroscopic measurements and gaining a full understanding of PECVD growth.
Calculation of the transport and relaxation properties of methane. I. Shear viscosity, viscomagnetic effects, and self-diffusion
Authors: Hellmann Robert , Bich Eckard , Vogel Eckhard , Dickinson Alan S. , Vesovic Velisa
Published: August 2008

Transport properties of pure methane gas have been calculated in the rigid-rotor approximation using the recently proposed intermolecular potential energy hypersurface [R. Hellmann et al., J. Chem. Phys. 128, 214303 (2008)] and the classical-trajectory method. Results are reported in the dilute-gas limit for shear viscosity, viscomagnetic coefficients, and self-diffusion in the temperature range of 80–1500 K. Compared with the best measurements, the calculated viscosity values are about 0.5% too high at room temperature, although the temperature dependence of the calculated values is in very good agreement with experiment between 210 and 390 K. For the shear viscosity, the calculations indicate that the corrections in the second-order approximation and those due to the angular-momentum polarization are small, less than 0.7%, in the temperature range considered. The very good agreement of the calculated values with the experimental viscosity data suggests that the rigid-rotor approximation should be very reasonable for the three properties considered. In general, the agreement for the other measured properties is within the experimental error.
Structural, optical, and electrical properties of epitaxial titanium oxide thin films on LaAlO3 substrate
Authors: Sbaï N. , Perrière J. , Gallas B. , Millon E. , Seiler W. , Bernard M. C.
Published: August 2008

Titanium oxide thin films were prepared by pulsed-laser deposition on LaAlO3 single crystal substrate at 700 °C. Pure anatase films are obtained at high oxygen pressure (10−1 mbar), while the rutile phase is evidenced at low oxygen pressure (10−5 mbar) despite a large oxygen deficiency (O/Ti=1.75). From asymmetric x-ray diffraction measurements, the in-plane epitaxial relationships be0tween the substrate and the titanium oxide phases are highlighted. Optical constants (refractive index n and extinction coefficient k) were deduced from ellipsometric measurements. The optical band gap energies of the anatase and rutile films are found to be 3.4 and 3.3 eV, respectively. Since the nearly stoichiometric anatase films are resistive (>103 Ω cm), the large oxygen deficiency in rutile films leads to noticeable increase in the conductivity due to the Ti3+ species, which supply electrons in the conduction band. At low temperature (T<200 K) the resistivity of rutile films versus temperature may be explained by a variable range hopping mechanism based on both two or three dimensional electron transfer between the Ti3+ and Ti4+ species.
Adiabatic connection forms in density functional theory: H2 and the He isoelectronic series
Authors: Peach Michael J. G. , Miller Adam M. , Teale Andrew M. , Tozer David J.
Published: August 2008

Full configuration interaction (FCI) data are used to quantify the accuracy of approximate adiabatic connection (AC) forms in describing two challenging problems in density functional theory—the singlet ground state potential energy curve of H2 in a restricted formalism and the energies of the helium isoelectronic series, H− to Ne8+. For H2, an exponential-based form yields a potential energy curve that is virtually indistinguishable from the FCI curve, eliminating the unphysical barrier to dissociation observed previously with a [1,1]-Padé-based form and with the random phase approximation. For the helium isoelectronic series, the Padé-based form gives the best overall description, followed by the exponential form, with errors that are orders of magnitude smaller than those from a standard hybrid functional. Particular attention is paid to the limiting behavior of the AC forms with increasing bond distance in H2 and increasing atomic number in the isoelectronic series; several forms describe both limits correctly. The study illustrates the very high quality results that can be obtained using exchange-correlation functionals based on simple AC forms, when near-exact data are used to determine the parameters in the forms.
Transport of transient solar wind particles in Earth’s cusps
Authors: Parks G. K. , Lee E. , Teste A. , Wilber M. , Lin N. , Canu P. , Dandouras I. , Rème H. , Fu S. Y. , Goldstein M. L.
Published: August 2008

An important problem in space physics still not understood well is how the solar wind enters the Earth’s magnetosphere. Evidence is presented that transient solar wind particles produced by solar disturbances can appear in the Earth’s mid-altitude (∼5RE geocentric) cusps with densities nearly equal to those in the magnetosheath. That these are magnetosheath particles is established by showing they have the same “flattop” electron distributions as magnetosheath electrons behind the bow shock. The transient ions are moving parallel to the magnetic field (B) toward Earth and often coexist with ionospheric particles that are flowing out. The accompanying waves include electromagnetic and broadband electrostatic noise emissions and Bernstein mode waves. Phase-space distributions show a mixture of hot and cold electrons and multiple ion species including field-aligned ionospheric O+ beams.
Linear and nonlinear optical properties of gold nanoparticle-Eu oxide composite thin films
Authors: Henari F. Z. , Dakhel A. A.
Published: August 2008

In this work, nanogold particles incorporated onto europium oxide films at levels of 4% and 7% were fabricated by a vacuum evaporation technique on glass and silicon substrates held at 200 °C. Samples were investigated by x-ray diffraction and linear and nonlinear optical absorption. The linear optical absorption data were measured in the UV-visible-near infrared spectral regions and from these data the energy gap and the surface plasmon resonance were determined. The third order nonlinear optical properties of the nanogold particles incorporated onto europium oxide films were measured using the Z-scan technique. Nonlinear absorption and refraction were performed using a continuous wave laser at 633 nm. A large value of third order nonlinearities was obtained with the samples.
Room temperature memory operation of a single InAs quantum dot layer in a GaAs∕AlGaAs heterostructure
Authors: Müller C. R. , Worschech L. , Heinrich J. , Höfling S. , Forchel A.
Published: August 2008

Room temperature (RT) memory operation of a single InAs quantum dot (QD) layer serving as floating gate is demonstrated. In an in-plane gated quantum-wire transistor, the charge state of the self-assembled InAs QDs is controlled by the applied gate voltage. Due to the floating-gate function of the QDs on a nearby transport channel, threshold hysteresis exceeding 200mV and storage times of several minutes are observed. The RT operation is attributed to an optimized positioning of the QDs at the site of a local minimum in the AlGaAs conduction band.
High Kondo temperature (TK∼80K) in self-assembled InAs quantum dots laterally coupled to nanogap electrodes
Authors: Shibata K. , Hirakawa K.
Published: August 2008

We have fabricated single electron tunneling structures by forming nanogap metallic electrodes directly upon single self-assembled InAs quantum dots (QDs). The fabricated samples exhibited clear Coulomb blockade effects. Furthermore, a clear Kondo effect was observed when strong coupling between the electrodes and the QDs was realized using a large QD with a diameter of ∼100nm. From the temperature dependence of the linear conductance at the Kondo valley, the Kondo temperature TK was determined to be ∼81K. This is the highest TK ever reported for artificial quantum nanostructures.
The use of doping spikes in GaN Gunn diodes
Authors: Macpherson R. F. , Dunn G. M.
Published: August 2008

The possibility of circumventing the difficulties of fine doping control in GaN Gunn diode devices by the substitution of a fully depleted p-type doping spike for the doping notch used to promote domain formation is explored using a Monte Carlo model. The p-type doping spike is a commonly used structure, but its potential use in GaN has not been previously evaluated. The results for a functional doping spike are compared, favorably, to those for a physically reasonable doping notch.
High field-effect mobility amorphous InGaZnO transistors with aluminum electrodes
Authors: Na Jong H. , Kitamura M. , Arakawa Y.
Published: August 2008

We report on the device characteristics of amorphous indium gallium zinc oxide thin-film transistors (TFTs) with aluminum (Al) electrodes. The TFTs exhibited a high performance with a field-effect mobility of 11.39 cm2/V s, a subthreshold swing of 181 mV/ decade, and an on-off ratio of 107. Further improvement in device performance was achieved by doping the source/drain contact regions, resulting in an enhanced mobility of 16.6 cm2/V s at an operating voltage as low as 5 V.
Dielectrophoretic manipulation of particles in a modified microfluidic H filter with multi-insulating blocks
Authors: Lewpiriyawong Nuttawut , Yang Chun , Lam Yee Cheong
Published: August 2008

The conventional microfluidic H filter is modified with multi-insulating blocks to achieve a flow-through manipulation and separation of microparticles. The device transports particles by exploiting electro-osmosis and electrophoresis, and manipulates particles by utilizing dielectrophoresis (DEP). Polydimethylsiloxane (PDMS) blocks fabricated in the main channel of the PDMS H filter induce a nonuniform electric field, which exerts a negative DEP force on the particles. The use of multi-insulating blocks not only enhances the DEP force generated, but it also increases the controllability of the motion of the particles, facilitating their manipulation and separation. Experiments were conducted to demonstrate the controlled flow direction of particles by adjusting the applied voltages and the separation of particles by size under two different input conditions, namely (i) a dc electric field mode and (ii) a combined ac and dc field mode. Numerical simulations elucidate the electrokinetic and hydrodynamic forces acting on a particle, with theoretically predicted particle trajectories in good agreement with those observed experimentally. In addition, the flow field was obtained experimentally with fluorescent tracer particles using the microparticle image velocimetry (μ-PIV) technique.
The identification of an osteoclastogenesis inhibitor through the inhibition of glyoxalase I
Authors: Kawatani Makoto , Okumura Hideo , Honda Kaori , Kanoh Naoki , Muroi Makoto , Dohmae Naoshi , Takami Masamichi , Kitagawa Mitsuhiro , Futamura Yushi , Imoto Masaya , Osada Hiroyuki
Published: August 2008

Osteoclasts, bone-resorptive multinucleated cells derived from hematopoietic stem cells, are associated with many bone-related diseases, such as osteoporosis. Osteoclast-targeting small-molecule inhibitors are valuable tools for studying osteoclast biology and for developing antiresorptive agents. Here, we have discovered that methyl-gerfelin (M-GFN), the methyl ester of the natural product gerfelin, suppresses osteoclastogenesis. By using M-GFN-immobilized beads, glyoxalase I (GLO1) was identified as an M-GFN-binding protein. GLO1 knockdown and treatment with an established GLO1 inhibitor in osteoclast progenitor cells interfered with osteoclast generation, suggesting that GLO1 activity is required for osteoclastogenesis. In cells, GLO1 plays a critical role in the detoxification of 2-oxoaldehydes, such as methylglyoxal. M-GFN inhibited the enzymatic activity of GLO1
in vitro
and
in situ.
Furthermore, the cocrystal structure of the GLO1/M-GFN complex revealed the binding mode of M-GFN at the active site of GLO1. These results suggest that M-GFN targets GLO1, resulting in the inhibition of osteoclastogenesis.
Enhanced contextual fear memory in central serotonin-deficient mice
Authors: Dai Jin-Xia , Han Hui-Li , Tian Meng , Cao Jun , Xiu Jian-Bo , Song Ning-Ning , Huang Ying , Xu Tian-Le , Ding Yu-Qiang , Xu Lin
Published: August 2008

Central serotonin (5-HT) dysregulation contributes to the susceptibility for mental disorders, including depression, anxiety, and posttraumatic stress disorder, and learning and memory deficits. We report that the formation of hippocampus-dependent spatial memory is compromised, but the acquisition and retrieval of contextual fear memory are enhanced, in central 5-HT-deficient mice. Genetic deletion of serotonin in the brain was achieved by inactivating
Lmx1b
selectively in the raphe nuclei of the brainstem, resulting in a near-complete loss of 5-HT throughout the brain. These 5-HT-deficient mice exhibited no gross abnormality in brain structures and had normal locomotor activity. Spatial learning in the Morris water maze was unaffected, but the retrieval of spatial memory was impaired. In contrast, contextual fear learning and memory induced by foot-shock conditioning was markedly enhanced, but this enhancement could be prevented by intracerebroventricular administration of 5-HT. Foot shock impaired long-term potentiation and facilitated long-term depression in hippocampal slices in WT mice but had no effect in 5-HT-deficient mice. Furthermore, bath application of 5-HT in 5-HT-deficient mice restored foot shock-induced alterations of hippocampal synaptic plasticity. Thus, central 5-HT regulates hippocampus-dependent contextual fear memory, and 5-HT modulation of hippocampal synaptic plasticity may be the underlying mechanism. The enhanced fear memory in 5-HT-deficient mice supports the notion that 5-HT deficiency confers susceptibility to posttraumatic stress disorder in humans.
How many tree species are there in the Amazon and how many of them will go extinct?
Authors: Hubbell Stephen P. , He Fangliang , Condit Richard , Borda-de-Água Luís , Kellner James , ter Steege Hans
Published: August 2008

New roads, agricultural projects, logging, and mining are claiming an ever greater area of once-pristine Amazonian forest. The Millennium Ecosystems Assessment (MA) forecasts the extinction of a large fraction of Amazonian tree species based on projected loss of forest cover over the next several decades. How accurate are these estimates of extinction rates? We use neutral theory to estimate the number, relative abundance, and range size of tree species in the Amazon metacommunity and estimate likely tree-species extinctions under published optimistic and nonoptimistic Amazon scenarios. We estimate that the Brazilian portion of the Amazon Basin has (or had) 11,210 tree species that reach sizes >10 cm DBH (stem diameter at breast height). Of these, 3,248 species have population sizes >1 million individuals, and, ignoring possible climate-change effects, almost all of these common species persist under both optimistic and nonoptimistic scenarios. At the rare end of the abundance spectrum, however, neutral theory predicts the existence of ≈5,308 species with <10,000 individuals each that are expected to suffer nearly a 50% extinction rate under the nonoptimistic deforestation scenario and an ≈37% loss rate even under the optimistic scenario. Most of these species have small range sizes and are highly vulnerable to local habitat loss. In ensembles of 100 stochastic simulations, we found mean total extinction rates of 20% and 33% of tree species in the Brazilian Amazon under the optimistic and nonoptimistic scenarios, respectively.
Phylogenetic trees and the future of mammalian biodiversity
Authors: Davies T. Jonathan , Fritz Susanne A. , Grenyer Richard , Orme C. David L. , Bielby Jon , Bininda-Emonds Olaf R. P. , Cardillo Marcel , Jones Kate E. , Gittleman John L. , Mace Georgina M. , Purvis Andy
Published: August 2008

Phylogenies describe the origins and history of species. However, they can also help to predict species' fates and so can be useful tools for managing the future of biodiversity. This article starts by sketching how phylogenetic, geographic, and trait information can be combined to elucidate present mammalian diversity patterns and how they arose. Recent diversification rates and standing diversity show different geographic patterns, indicating that cradles of diversity have moved over time. Patterns in extinction risk reflect both biological differences among mammalian lineages and differences in threat intensity among regions. Phylogenetic comparative analyses indicate that for small-bodied mammals, extinction risk is governed mostly by where the species live and the intensity of the threats, whereas for large-bodied mammals, ecological differences also play an important role. This modeling approach identifies species whose intrinsic biology renders them particularly vulnerable to increased human pressure. We outline how the approach might be extended to consider future trends in anthropogenic drivers, to identify likely future battlegrounds of mammalian conservation, and the likely casualties. This framework could help to highlight consequences of choosing among different future climatic and socioeconomic scenarios. We end by discussing priority-setting, showing how alternative currencies for diversity can suggest very different priorities. We argue that aiming to maximize long-term evolutionary responses is inappropriate, that conservation planning needs to consider costs as well as benefits, and that proactive conservation of largely intact systems should be part of a balanced strategy.
Extinction and the spatial dynamics of biodiversity
Authors: Jablonski David
Published: August 2008

The fossil record amply shows that the spatial fabric of extinction has profoundly shaped the biosphere; this spatial dimension provides a powerful context for integration of paleontological and neontological approaches. Mass extinctions evidently alter extinction selectivity, with many factors losing effectiveness except for a positive relation between survivorship and geographic range at the clade level (confirmed in reanalyses of end-Cretaceous extinction data). This relation probably also holds during “normal” times, but changes both slope and intercept with increasing extinction. The strong geographical component to clade dynamics can obscure causation in the extinction of a feature or a clade, owing to hitchhiking effects on geographic range, so that multifactorial analyses are needed. Some extinctions are spatially complex, and regional extinctions might either reset a diversity ceiling or create a diversification debt open to further diversification or invasion. Evolutionary recoveries also exhibit spatial dynamics, including regional differences in invasibilty, and expansion of clades from the tropics fuels at least some recoveries, as well as biodiversity dynamics during normal times. Incumbency effects apparently correlate more closely with extinction intensities than with standing diversities, so that regions with higher local and global extinctions are more subject to invasion; the latest Cenozoic temperate zones evidently received more invaders than the tropics or poles, but this dynamic could shift dramatically if tropical diversity is strongly depleted. The fossil record can provide valuable insights, and their application to present-day issues will be enhanced by partitioning past and present-day extinctions by driving mechanism rather than emphasizing intensity.
A phylogenetic perspective on the distribution of plant diversity
Authors: Donoghue Michael J.
Published: August 2008

Phylogenetic studies are revealing that major ecological niches are more conserved through evolutionary history than expected, implying that adaptations to major climate changes have not readily been accomplished in all lineages. Phylogenetic niche conservatism has important consequences for the assembly of both local communities and the regional species pools from which these are drawn. If corridors for movement are available, newly emerging environments will tend to be filled by species that filter in from areas in which the relevant adaptations have already evolved, as opposed to being filled byin situevolution of these adaptations. Examples include intercontinental disjunctions of tropical plants, the spread of plant lineages around the Northern Hemisphere after the evolution of cold tolerance, and the radiation of northern alpine plants into the Andes. These observations highlight the role of phylogenetic knowledge and historical biogeography in explanations of global biodiversity patterns. They also have implications for the future of biodiversity.
Patterns of biodiversity and endemism on Indo-West Pacific coral reefs
Authors: Reaka Marjorie L. , Rodgers Paula J. , Kudla Alexei U.
Published: August 2008

Diversity of the primary groups of contemporary Indo-West Pacific coral reef organisms, including mantis shrimps (stomatopod crustaceans), peaks in the Indo-Australian Archipelago (IAA), reaches a lower peak in East Africa and Madagascar [Indian Ocean continental (IOC)], and declines in the central Indian Ocean (IO) and Central Pacific (CP). Percent endemism in stomatopods (highest in the IAA, high in the IOC, lower in regions adjacent to centers, and moderate in the CP) correlates positively with species diversity (this varies with scale) and inversely with species body size. Because it constrains reproductive traits and dispersal, body size is a reliable indicator of speciation and extinction potential in reef stomatopods and probably most marine organisms. Assemblages are dominated by small-sized species in the IAA and IOC. Both speciation and extinction likely are high, resulting in especially high endemism (small ranges reflect both originating and disappearing species) in these regions. Rates of speciation exceed extinction, yielding centers of diversity (especially in the IAA). Dispersal slows speciation and extinction in areas adjacent to these centers. Body size declines toward the CP, especially in atoll environments. Here the wheels of speciation and extinction again spin rapidly but in the opposite direction (extinction > speciation), yielding low diversity and moderate endemism. We conclude that life histories, dispersal, and speciation/extinction dynamics are primary agents that mold patterns of diversity and endemism. Historical factors, currents, productivity, and species diversity itself (through ecological interactions) also influence these patterns, in some cases by altering body size.
Dynamics of origination and extinction in the marine fossil record
Authors: Alroy John
Published: August 2008

The discipline-wide effort to database the fossil record at the occurrence level has made it possible to estimate marine invertebrate extinction and origination rates with much greater accuracy. The new data show that two biotic mechanisms have hastened recoveries from mass extinctions and confined diversity to a relatively narrow range over the past 500 million years (Myr). First, a drop in diversity of any size correlates with low extinction rates immediately afterward, so much so that extinction would almost come to a halt if diversity dropped by 90%. Second, very high extinction rates are followed by equally high origination rates. The two relationships predict that the rebound from the current mass extinction will take at least 10 Myr, and perhaps 40 Myr if it rivals the Permo-Triassic catastrophe. Regardless, any large event will result in a dramatic ecological and taxonomic restructuring of the biosphere. The data also confirm that extinction and origination rates both declined through the Phanerozoic and that several extinctions in addition to the Permo-Triassic event were particularly severe. However, the trend may be driven by taxonomic biases and the rates vary in accord with a simple log normal distribution, so there is no sharp distinction between background and mass extinctions. Furthermore, the lack of any significant autocorrelation in the data is inconsistent with macroevolutionary theories of periodicity or self-organized criticality.
The spontaneous expression of pride and shame: Evidence for biologically innate nonverbal displays
Authors: Tracy Jessica L. , Matsumoto David
Published: August 2008

The present research examined whether the recognizable nonverbal expressions associated with pride and shame may be biologically innate behavioral responses to success and failure. Specifically, we tested whether sighted, blind, and congenitally blind individuals across cultures spontaneously display pride and shame behaviors in response to the same success and failure situations—victory and defeat at the Olympic or Paralympic Games. Results showed that sighted, blind, and congenitally blind individuals from >30 nations displayed the behaviors associated with the prototypical pride expression in response to success. Sighted, blind, and congenitally blind individuals from most cultures also displayed behaviors associated with shame in response to failure. However, culture moderated the shame response among sighted athletes: it was less pronounced among individuals from highly individualistic, self-expression-valuing cultures, primarily in North America and West Eurasia. Given that congenitally blind individuals across cultures showed the shame response to failure, findings overall are consistent with the suggestion that the behavioral expressions associated with both shame and pride are likely to be innate, but the shame display may be intentionally inhibited by some sighted individuals in accordance with cultural norms.
Adaptive sugar sensors in hypothalamic feeding circuits
Authors: Williams Rhiannan H. , Alexopoulos Haris , Jensen Lise T. , Fugger Lars , Burdakov Denis
Published: August 2008

Brain glucose sensing is critical for healthy energy balance, but how appropriate neurocircuits encode both small changes and large background values of glucose levels is unknown. Here, we report several features of hypothalamic orexin neurons, cells essential for normal wakefulness and feeding: (
i
) A distinct group of orexin neurons exhibits only transient inhibitory responses to sustained rises in sugar levels; (
ii
) this sensing strategy involves time-dependent recovery from inhibition via adaptive closure of leak-like K
+
channels; (
iii
) combining transient and sustained glucosensing allows orexin cell firing to maintain sensitivity to small fluctuations in glucose levels while simultaneously encoding a large range of baseline glucose concentrations. These data provide insights into how vital behavioral orchestrators sense key features of the internal environment while sustaining a basic activity tone required for the stability of consciousness.
Homage to Linnaeus: How many parasites? How many hosts?
Authors: Dobson Andy , Lafferty Kevin D. , Kuris Armand M. , Hechinger Ryan F. , Jetz Walter
Published: August 2008

Estimates of the total number of species that inhabit the Earth have increased significantly since Linnaeus's initial catalog of 20,000 species. The best recent estimates suggest that there are ≈6 million species. More emphasis has been placed on counts of free-living species than on parasitic species. We rectify this by quantifying the numbers and proportion of parasitic species. We estimate that there are between 75,000 and 300,000 helminth species parasitizing the vertebrates. We have no credible way of estimating how many parasitic protozoa, fungi, bacteria, and viruses exist. We estimate that between 3% and 5% of parasitic helminths are threatened with extinction in the next 50 to 100 years. Because patterns of parasite diversity do not clearly map onto patterns of host diversity, we can make very little prediction about geographical patterns of threat to parasites. If the threats reflect those experienced by avian hosts, then we expect climate change to be a major threat to the relatively small proportion of parasite diversity that lives in the polar and temperate regions, whereas habitat destruction will be the major threat to tropical parasite diversity. Recent studies of food webs suggest that ≈75% of the links in food webs involve a parasitic species; these links are vital for regulation of host abundance and potentially for reducing the impact of toxic pollutants. This implies that parasite extinctions may have unforeseen costs that impact the health and abundance of a large number of free-living species.
Identification of a vesicular aspartate transporter
Authors: Miyaji Takaaki , Echigo Noriko , Hiasa Miki , Senoh Shigenori , Omote Hiroshi , Moriyama Yoshinori
Published: August 2008

Aspartate is an excitatory amino acid that is costored with glutamate in synaptic vesicles of hippocampal neurons and synaptic-like microvesicles (SLMVs) of pinealocytes and is exocytosed and stimulates neighboring cells by binding to specific cell receptors. Although evidence increasingly supports the occurrence of aspartergic neurotransmission, this process is still debated because the mechanism for the vesicular storage of aspartate is unknown. Here, we show that sialin, a lysosomal H+/sialic acid cotransporter, is present in hippocampal synaptic vesicles and pineal SLMVs. RNA interference of sialin expression decreased exocytosis of aspartate and glutamate in pinealocytes. Proteoliposomes containing purified sialin actively accumulated aspartate and glutamate to a similar extent when inside positive membrane potential is imposed as the driving force. Sialin carrying a mutation found in people suffering from Salla disease (R39C) was completely devoid of aspartate and glutamate transport activity, although it retained appreciable H+/sialic acid cotransport activity. These results strongly suggest that sialin possesses dual physiological functions and acts as a vesicular aspartate/glutamate transporter. It is possible that people with Salla disease lose aspartergic (and also the associated glutamatergic) neurotransmission, and this could provide an explanation for why Salla disease causes severe neurological defects.
Moths produce extremely quiet ultrasonic courtship songs by rubbing specialized scales
Authors: Nakano Ryo , Skals Niels , Takanashi Takuma , Surlykke Annemarie , Koike Takuji , Yoshida Keisuke , Maruyama Hirotaka , Tatsuki Sadahiro , Ishikawa Yukio
Published: August 2008

Insects have evolved a marked diversity of mechanisms to produce loud conspicuous sounds for efficient communication. However, the risk of eavesdropping by competitors and predators is high. Here, we describe a mechanism for producing extremely low-intensity ultrasonic songs (46 dB sound pressure level at 1 cm) adapted for private sexual communication in the Asian corn borer moth,Ostrinia furnacalis. During courtship, the male rubs specialized scales on the wing against those on the thorax to produce the songs, with the wing membrane underlying the scales possibly acting as a sound resonator. The male's song suppresses the escape behavior of the female, thereby increasing his mating success. Our discovery of extremely low-intensity ultrasonic communication may point to a whole undiscovered world of private communication, using “quiet” ultrasound.
The Namesake in Persian
Authors: Haddadian-Moghaddam Esmaeil
Published: August 2008

Translation and literary translation in particular, no longer can be seen as a static activity. In Austermühl’s words, the antiquated image of a lone translator, armed only with a pencil or typewriter and surrounded by dusty books, is no longer realistic. The translators are now learning to apply the new communication technologies like Internet in their work. The web log as a recent phenomenon in the cyber world can be applied in literary translation. However, it has been overlooked in translation studies, partly, in author’s opinion, because of its novelty but to large extend, because of its popularity as a platform or a personal diary for the novice bloggers, the authors of the web logs.

In this article, the application of a web log by an Iranian literary translator in his Persian translation of Jhumpa Lahiri’s The Namesake is examined. By providing examples of the discussions between the translator and his visitors (readers), and by incorporating the web log in a model of translation studies, The Holmes–Toury map of translation studies, he tries to pinpoint the advantages of web log in literary translation in respect to its application as an online translation workshop. The author argues that the web log can be thoroughly applied in literary translation provided that the translator optimizes the quality of his web log or workshop by acknowledging the growing importance of new technologies available for him; and making informed decisions for the effective use of translation technology. What distinguishes the online translation workshop from its traditional one is its round-the-clock opening, facilitated interaction with the translator, absence of any formal setting and formality and instant access to available sources in Internet.

The application of weblogs as an online workshop has some advantages for the literary translator: acting as a mediator between the translator and his potential readers; sharing the experiences, problems and seeking advice; and, creating a virtual, universal world around the translation which is bigger than his small, personal world.
Crucial role of nitric oxide synthases system in endothelium-dependent hyperpolarization in mice
Authors: Takaki Aya , Morikawa Keiko , Tsutsui Masato , Murayama Yoshinori , Tekes Ender , Yamagishi Hiroto , Ohashi Junko , Yada Toyotaka , Yanagihara Nobuyuki , Shimokawa Hiroaki
Published: August 2008

The endothelium plays an important role in maintaining vascular homeostasis by synthesizing and releasing several relaxing factors, such as prostacyclin, nitric oxide (NO), and endothelium-derived hyperpolarizing factor (EDHF). We have previously demonstrated in animals and humans that endothelium-derived hydrogen peroxide (H2O2) is an EDHF that is produced in part by endothelial NO synthase (eNOS). In this study, we show that genetic disruption of all three NOS isoforms (neuronal [nNOS], inducible [iNOS], and endothelial [eNOS]) abolishes EDHF responses in mice. The contribution of the NOS system to EDHF-mediated responses was examined in eNOS−/−, n/eNOS−/−, and n/i/eNOS−/− mice. EDHF-mediated relaxation and hyperpolarization in response to acetylcholine of mesenteric arteries were progressively reduced as the number of disrupted NOS genes increased, whereas vascular smooth muscle function was preserved. Loss of eNOS expression alone was compensated for by other NOS genes, and endothelial cell production of H2O2 and EDHF-mediated responses were completely absent in n/i/eNOS−/− mice, even after antihypertensive treatment with hydralazine. NOS uncoupling was not involved, as modulation of tetrahydrobiopterin (BH4) synthesis had no effect on EDHF-mediated relaxation, and the BH4/dihydrobiopterin (BH2) ratio was comparable in mesenteric arteries and the aorta. These results provide the first evidence that EDHF-mediated responses are dependent on the NOSs system in mouse mesenteric arteries.
Divalent Cations Regulate Connexin Hemichannels by Modulating Intrinsic Voltage-dependent Gating
Authors: Verselis Vytas K. , Srinivas Miduturu
Published: August 2008

Connexin hemichannels are robustly regulated by voltage and divalent cations. The basis of voltage-dependent gating, however, has been questioned with reports that it is not intrinsic to hemichannels, but rather is derived from divalent cations acting as gating particles that block the pore in a voltage-dependent manner. Previously, we showed that connexin hemichannels possess two types of voltage-dependent gating, termed Vj and loop gating, that in Cx46 operate at opposite voltage polarities, positive and negative, respectively. Using recordings of single Cx46 hemichannels, we found both forms of gating persist in solutions containing no added Mg2+ and EGTA to chelate Ca2+. Although loop gating persists, it is significantly modulated by changing levels of extracellular divalent cations. When extracellular divalent cation concentrations are low, large hyperpolarizing voltages, exceeding −100 mV, could still drive Cx46 hemichannels toward closure. However, gating is characterized by continuous flickering of the unitary current interrupted by occasional, brief sojourns to a quiet closed state. Addition of extracellular divalent cations, in this case Mg2+, results in long-lived residence in a quiet closed state, suggesting that hyperpolarization drives the hemichannel to close, perhaps by initiating movements in the extracellular loops, and that divalent cations stabilize the fully closed conformation. Using excised patches, we found that divalent cations are only effective from the extracellular side, indicative that the binding site is not cytoplasmic or in the pore, but rather extracellular. Vj gating remains essentially unaffected by changing levels of extracellular divalent cations. Thus, we demonstrate that both forms of voltage dependence are intrinsic gating mechanisms in Cx46 hemichannels and that the action of external divalent cations is to selectively modulate loop gating.
Glucose and GLP-1 Stimulate cAMP Production via Distinct Adenylyl Cyclases in INS-1E Insulinoma Cells
Authors: Ramos Lavoisier S. , Zippin Jonathan Hale , Kamenetsky Margarita , Buck Jochen , Levin Lonny R.
Published: August 2008

In β cells, both glucose and hormones, such as GLP-1, stimulate production of the second messenger cAMP, but glucose and GLP-1 elicit distinct cellular responses. We now show in INS-1E insulinoma cells that glucose and GLP-1 produce cAMP with distinct kinetics via different adenylyl cyclases. GLP-1 induces a rapid cAMP signal mediated by G protein–responsive transmembrane adenylyl cyclases (tmAC). In contrast, glucose elicits a delayed cAMP rise mediated by bicarbonate, calcium, and ATP-sensitive soluble adenylyl cyclase (sAC). This glucose-induced, sAC-dependent cAMP rise is dependent upon calcium influx and is responsible for the glucose-induced activation of the mitogen-activated protein kinase (ERK1/2) pathway. These results demonstrate that sAC-generated and tmAC-generated cAMP define distinct signaling cascades.
Arabidopsis thalianaregulatory element analyzer
Authors: Choudhury Ananyo , Lahiri Ansuman
Published: August 2008

Summary: In the Arabidopsis thaliana regulatory element analyzer (AtREA) server, we have integrated sequence data, genome-wide expression data and functional annotation data in three application modules which will be useful to identify major regulatory targets of a user-provided cis-regulatory element (CRE), study different features of CRE distribution and evaluate the role of a set of CREs in the regulation of gene expression—independently as well as in combination with other user-provided CREs.

Availability: AtREA is freely available at http://www.bioinformatics.org/grn/atrea.html.

Contact:  ananyo.c@gmail.com
(E)-Methyl N′-[1-(2-hydroxyphenyl)ethylidene]hydrazinecarboxylate
Authors: Zhu Bin , Cheng Xiang-Wei
Published: August 2008

The molecule of the title compound, C10H12N2O3, adopts a trans configuration with respect to the C=N bond. The dihedral angle between the benzene ring and the hydrazinecarboxylate plane is 8.98 (7)°. Intramolecular O—H...N and C—H...N hydrogen bonds are observed. Molecules are linked into chains along the c axis by N—H...O hydrogen bonds. In addition, C—H...π interactions are observed.
3,6-Dichlorocatechol
Authors: Xie An-Le , Ding Tong-Jian , Cao Xiao-Ping
Published: August 2008

The title compound, C6H4Cl2O2, exhibits a two-dimensional supramolecular hydrogen-bonded network and forms a three-dimensional network supramolecular structure via hydrogen bonds and π–π stacking of benzene rings. The π–π interactions are between the benzene rings of centrosymmetrically related molecules, with centroid–centroid distances of 3.7676 (13) and 3.7107 (13) Å.
N-Phenylpiperidine-1-carbothioamide
Authors: Li Yu-Feng , Jian Fang-Fang
Published: August 2008

The title compound, C12H16N2S, was prepared by the reaction of with phenyl isothiocyanate and piperidine. In the crystal structure, the molecule exhibits intermolecular N—H...S hydrogen bonds and weak intramolecular C—H...S and C—H...N hydrogen-bonding interactions.
N-(Imidazol-1-ylmethyl)phthalimide
Authors: Wang Su-Qing , Jian Fang-Fang , Liu Huan-Qiang
Published: August 2008

The title compound [systematic name: 2-(imidazol-1-ylmethyl)isoindole-1,3-dione], C12H9N3O2, was prepared by reaction of N-(bromomethyl)phthalimide and imidazole in chloroform solution. The crystal structure is stabilized by weak intermolecular C—H...π interactions and intermolecular π–π interactions with centroid–centroid distances in the range 3.6469 (8)–3.8831 (9) Å.
N
2,N
2,N
4,N
4,N
6,N
6-Hexapropyl-1,3,5-triazine-2,4,6-triamine
Authors: Li Yu-Feng , Jian Fang-Fang
Published: August 2008

The title compound, C21H42N6, was prepared by the reaction of 2,4,6-trichloro-1,3,5-triazine with dipropylamine. The structure of the molecule is tripodal.
catena-Poly[[aqua(ethyl anilinophosphonato-κO)sodium(I)]-di-μ-aqua]
Authors: Fu Zhiyong , Bai Shuqiong
Published: August 2008

In the title compound, [Na(C8H11NO3P)(H2O)3]
n
, the sodium cation is octahedrally coordinated by five water molecules and one O-bonded ethyl anilinophosphonate anion. Four of the water molecules bridge to adjacent sodium ions, resulting in an infinite chain of edge-sharing NaO6 polyhedra. A network of N—H...O and O—H...O hydrogen bonds helps to stabilize the crystal structure.