bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects of Fast ForWord Language on the Phonemic Awareness and Reading Skills of School-Age Children With Language Impairments and Poor Reading Skills
Authors: Loeb Diane Frome , Gillam Ronald B. , Hoffman LaVae , Brandel Jayne , Marquis Janet
Published: November 2009

Purpose

To examine the efficacy of Fast ForWord Language (FFW-L) and 2 other interventions for improving the phonemic awareness and reading skills of children with specific language impairment with concurrent poor reading skills.

Method

A total of 103 children (age 6;0 to 8;11 [years;months]) with language impairment and poor reading skills participated. The children received either FFW-L computerized intervention, a computer-assisted language intervention (CALI), an individualized language intervention (ILI), or an attention control (AC) computer program.

Results

The children in the FFW-L, CALI, and ILI conditions made significantly greater gains in blending sounds in words compared with the AC group at immediate posttest. Long-term gains 6 months after treatment were not significant but yielded a medium effect size for blending sounds in words. None of the interventions led to significant changes in reading skills.

Conclusion

The improvement in phonemic awareness, but not reading, in the FFW-L, CALI, and ILI interventions limits their use with children who have language impairment and poor reading skills. Similar results across treatment conditions suggest that acoustically modified speech was not a necessary component for improving phonemic awareness.
Transcribing the Speech of Children With Cochlear Implants: Clinical Application of Narrow Phonetic Transcriptions
Authors: Teoh Amy P. , Chin Steven B.
Published: November 2009

Purpose

The phonological systems of children with cochlear implants may include segment inventories that contain both target and nontarget speech sounds. These children may not consistently follow phonological rules of the target language. These issues present a challenge for the clinical speech-language pathologist who uses phonetic transcriptions to evaluate speech production skills and to develop a plan of care. The purposes of this tutorial are to (a) identify issues associated with phonetic transcriptions of the speech of children with cochlear implants and (b) discuss implications for assessment.

Method

Narrow transcription data from an ongoing, longitudinal research study were catalogued and reviewed. Study participants had at least 5 years of cochlear implant experience and used spoken American English as a primary means of communication. In this tutorial, selected phonetic symbols and phonetic phenomena are reviewed.

Conclusions

A set of principles for phonetic transcriptions is proposed. Narrow phonetic transcriptions that include all segment possibilities in the International Phonetic Alphabet and extensions for disordered speech are needed to capture the subtleties of the speech of children with cochlear implants. Narrow transcriptions also may play a key role in planning treatment.
Evidence-Based Systematic Review: Effects of Neuromuscular Electrical Stimulation on Swallowing and Neural Activation
Authors: Clark Heather , Lazarus Cathy , Arvedson Joan , Schooling Tracy , Frymark Tobi
Published: November 2009

Purpose

To systematically review the literature examining the effects of neuromuscular electrical stimulation (NMES) on swallowing and neural activation. The review was conducted as part of a series examining the effects of oral motor exercises (OMEs) on speech, swallowing, and neural activation.

Method

A systematic search was conducted to identify relevant studies published in peer-reviewed journals from 1960 to 2007. All studies meeting the exclusion/inclusion criteria were appraised for quality and categorized as efficacy or exploratory research based on predetermined criteria.

Results

Out of 899 citations initially identified for the broad review of OMEs, 14 articles relating to NMES qualified for inclusion. Most of the studies (10/14) were considered exploratory research, and many had significant methodological limitations.

Conclusions

This systematic review reveals that surface NMES to the neck has been most extensively studied with promising findings, yet high-quality controlled trials are needed to provide evidence of efficacy. Surface NMES to the palate, faucial pillars, and pharynx has been explored in Phase I research, but no evidence of efficacy is currently available. Intramuscular NMES has been investigated in a single Phase I exploratory study. Additional research is needed to document the effects of such protocols on swallowing performance.
Evidence-Based Systematic Review: Effects of Nonspeech Oral Motor Exercises on Speech
Authors: McCauley Rebecca J. , Strand Edythe , Lof Gregory L. , Schooling Tracy , Frymark Tobi
Published: November 2009

Purpose

The purpose of this systematic review was to examine the current evidence for the use of oral motor exercises (OMEs) on speech (i.e., speech physiology, speech production, and functional speech outcomes) as a means of supporting further research and clinicians' use of evidence-based practice.

Method

The peer-reviewed literature from 1960 to 2007 was searched for articles examining the use of OMEs to affect speech physiology, production, or functional outcomes (i.e., intelligibility). Articles that met selection criteria were appraised by 2 reviewers and vetted by a 3rd for methodological quality, then characterized as efficacy or exploratory studies.

Results

Fifteen studies met inclusion criteria; of these, 8 included data relevant to the effects of OMEs on speech physiology, 8 on speech production, and 8 on functional speech outcomes. Considerable variation was noted in the participants, interventions, and treatment schedules. The critical appraisals identified significant weaknesses in almost all studies.

Conclusions

Insufficient evidence to support or refute the use of OMEs to produce effects on speech was found in the research literature. Discussion is largely confined to a consideration of the need for more well-designed studies using well-described participant groups and alternative bases for evidence-based practice.
Sintering and crystallization behavior of CaMgSi2O6–NaFeSi2O6 based glass-ceramics
Authors: Goel Ashutosh , Ferrari Anna Maria , Kansal Ishu , Pascual Maria J. , Barbieri Luisa , Bondioli Federica , Lancellotti Isabella , Ribeiro Manuel J. , Ferreira José M. F.
Published: November 2009

We report on the synthesis, sintering, and crystallization behaviors of a glass with a composition corresponding to 90 mol % CaMgSi2O6−10 mol % NaFeSi2O6. The investigated glass composition crystallized superficially immediately after casting of the melt and needs a high cooling rate (rapid quenching) in order to produce an amorphous glass. Differential thermal analysis and hot-stage microscopy were employed to investigate the glass forming ability, sintering behavior, relative nucleation rate, and crystallization behavior of the glass composition. The crystalline phase assemblage in the glass-ceramics was studied under nonisothermal heating conditions in the temperature range of 850–950 °C in both air and N2 atmosphere. X-ray diffraction studies adjoined with the Rietveld–reference intensity ratio method were employed to quantify the amount of crystalline phases, while electron microscopy was used to shed some light on the microstructure of the resultant glass-ceramics. Well sintered glass-ceramics with diopside as the primary crystalline phase were obtained where the amount of diopside varied with the heating conditions.
Hybrid organic/inorganic nanocomposite as a quasi-one-dimensional semiconductor under ambient conditions
Authors: Kumar P. Suresh , Kumar Sandeep , Lakshminarayanan V.
Published: November 2009

We describe here a novel hybrid organic/inorganic nanocomposite of hexahexyloxytriphenylene (HAT6) which is a columnar discotic liquid crystal and gold tetrachloride, an inorganic dopant, showing enhanced dc and ac electrical conductivity by several orders of magnitude at ambient conditions vis-à-vis the respective pure components. The composites at appropriate concentrations of the dopants retain the columnar hexagonal phase, which is confirmed by polarizing optical microscopy, differential scanning calorimetry, and x-ray scattering techniques. The UV-vis spectral studies show that the composites absorb in the entire visible range due to the formation of radical cations of the discotic molecules, making it a potential candidate for solar cell applications.
First-principles study of methane dehydrogenation on a bimetallic Cu/Ni(111) surface
Authors: An Wei , Zeng X. C. , Turner C. Heath
Published: November 2009

We present density-functional theory calculations of the dehydrogenation of methane and CHx (x=1–3) on a Cu/Ni(111) surface, where Cu atoms are substituted on the Ni surface at a coverage of 14 monolayer. As compared to the results on other metal surfaces, including Ni(111), a similar activation mechanism with different energetics is found for the successive dehydrogenation of CH4 on the Cu/Ni(111) surface. In particular, the activation energy barrier (Eact) for CH→C+H is found to be 1.8 times larger than that on Ni(111), while Eact for CH4→CH3+H is 1.3 times larger. Considering the proven beneficial effect of Cu observed in the experimental systems, our findings reveal that the relative Eact in the successive dehydrogenation of CH4 plays a key role in impeding carbon formation during the industrial steam reforming of methane. Our calculations also indicate that previous scaling relationships of the adsorption energy (Eads) for CHx (x=1–3) and carbon on pure metals also hold for several Ni(111)-based alloy systems.
First-principles molecular dynamics simulations at solid-liquid interfaces with a continuum solvent
Authors: Sánchez Verónica M. , Sued Mariela , Scherlis Damián A.
Published: November 2009

Continuum solvent models have become a standard technique in the context of electronic structure calculations, yet no implementations have been reported capable to perform molecular dynamics at solid-liquid interfaces. We propose here such a continuum approach in a density functional theory framework using plane-wave basis sets and periodic boundary conditions. Our work stems from a recent model designed for Car–Parrinello simulations of quantum solutes in a dielectric medium [D. A. Scherlis et al., J. Chem. Phys. 124, 074103 (2006)], for which the permittivity of the solvent is defined as a function of the electronic density of the solute. This strategy turns out to be inadequate for systems extended in two dimensions: the dependence of the dielectric function on the electronic density introduces a new term in the Kohn–Sham potential, which becomes unphysically large at the interfacial region, seriously affecting the convergence of the self-consistent calculations. If the dielectric medium is properly redefined as a function of the atomic coordinates, a good convergence is obtained and the constant of motion is conserved during the molecular dynamics simulations. The Poisson problem is solved using a multigrid method, and in this way Car–Parrinello molecular dynamics simulations of solid-liquid interfaces can be performed at a very moderate computational cost. This scheme is employed to investigate the acid-base equilibrium at the TiO2-water interface. The aqueous behavior of titania surfaces has stimulated a large amount of experimental research, but many open questions remain concerning the molecular mechanisms determining the chemistry of the interface. Here we make an attempt to answer some of them, putting to the test our continuum model.
Cumulant decomposition of reduced density matrices, multireference normal ordering, and Wicks theorem: A spin-free approach
Authors: Shamasundar K. R.
Published: November 2009

We propose a spin-free approach to the cumulant decomposition of reduced density matrices of singlet and spin-rotation or SU(2) invariant ensemble of nonsinglet states as in [W. Kutzelnigg and D. Mukherjee, J. Chem. Phys. 110, 2800 (1999); 116, 4787 (2002)]. We provide a simple recursive procedure to obtain expressions which relate different spin components of spin-orbital reduced density matrices and cumulants of such states to the spin-free counterparts. These results are used to set up a spin-summation procedure to arrive at a definition of spin-free cumulants of any order. Alternatively, an analytic formula for the spin-free form resulting from a spin summation involving product of two spin-orbital cumulants is derived and its utility in spin-free cumulant decomposition of reduced density matrices is demonstrated. This leads to suitable definitions of spin-free analog of multireference normal ordering and the associated Wicks theorem. The results of this formulation are expected to be useful in investigations of spin-free multireference internally contracted coupled-cluster methods where cumulant approximations to the active reduced density matrices are employed.
Neutron scattering study of the dynamics of a polymer melt under nanoscopic confinement
Authors: Krutyeva Margarita , Martin Jaime , Arbe Arantxa , Colmenero Juan , Mijangos Carmen , Schneider Gerald J. , Unruh Tobias , Su Yixi , Richter Dieter
Published: November 2009

Poly(ethylene oxide) confined in an anodic aluminum oxide solid matrix has been studied by different neutron scattering techniques in the momentum transfer (Q⃗) range 0.2≤Q=|Q⃗|≤1.9 Å−1. The cylindrical pores of the matrix present a diameter (40 nm) much smaller than their length (150 μm) and are parallel and hexagonally ordered. In particular, we investigated the neutron intensity scattered for two orientations of the sample with respect to the incident beam, for which the Q⃗ direction was either parallel or perpendicular to the pores for a scattering angle of 90°. Diffuse neutron scattering at room temperature has shown that the aluminum oxide has amorphous structure and the polymer in the nanoporous matrix is partially crystallized. Concerning the dynamical behavior, for Q<1 Å−1, the spectra show Rouse-like motions indistinguishable from those in the bulk within the uncertainties. In the high-Q limit we observe a slowing down of the dynamics with respect to the bulk behavior that evidences an effect of confinement. This effect is more pronounced for molecular displacements perpendicular to the pore axis than for parallel displacements. Our results clearly rule out the strong corset effect proposed for this polymer from nuclear magnetic resonance (NMR) studies and can be rationalized by assuming that the interactions with the pore walls affect one to two adjacent monomer monolayers.
Thermal infrared imaging of crop canopies for the remote diagnosis and quantification of plant responses to water stress in the field
Authors: Jones Hamlyn G. , Serraj Rachid , Loveys Brian R. , Xiong Lizhong , Wheaton Ashley , Price Adam H.
Published: November 2009

Thermal imaging using infrared (IR) is now an established technology for the study of stomatal responses and for phenotyping plants for differences in stomatal behaviour. This paper outlines the potential applications of IR sensing in drought phenotyping, with particular emphasis on a description of the problems with extrapolation of the technique from the study of single leaves in controlled environments to the study of plant canopies is field plots, with examples taken from studies on grapevine (Vitis vinifera L.) and rice (Oryza sativa L.). Particular problems include the sensitivity of leaf temperature (and potentially the temperature of reference surfaces) to both temporal and spatial variation in absorbed radiation, with leaf temperature varying by as much as 15°C between full sun and deep shade. Examples of application of the approach to phenotyping in the field and the steps in data analysis are outlined, demonstrating that clear genotypic variation may be detected despite substantial variation in soil moisture status or incident radiation by the use of appropriate normalisation techniques.
An infrared-based coefficient to screen plant environmental stress: concept, test and applications
Authors: Qiu Guo Yu , Omasa Kenji , Sase Sadanori
Published: November 2009

By introducing a reference dry leaf (a leaf without transpiration), a formerly proposed plant transpiration transfer coefficient (hat) was applied to detect environmental stress caused by water shortage and high temperature on melon, tomato and lettuce plants under various conditions. Results showed that there were obvious differences between leaf temperature, dry reference leaf temperature and air temperature. The proposed coefficient hat could integrate the three temperatures and quantitatively evaluate the environmental stress of plants. Experimental results showed that the water stress of melon plants under two irrigation treatments was clearly distinguished by using the coefficient. The water stress of a tomato plant as the soil dried under a controlled environmental condition was sensitively detected by using hat. A linear relationship between hat and conventional crop water stress index was revealed with a regression determination coefficient R2 = 0.97. Further, hat was used to detect the heat stress of lettuce plants under high air temperature conditions (28.7°C) with three root temperature treatments (21.5, 25.9 and 29.5°C). The canopy temperature under these treatments was respectively 26.44, 27.15 and 27.46°C and the corresponding hat value was –1.11, –0.74 and –0.59. Heat stress was also sensitively detected using hat. The main advantage of hat is its simplicity for use in infrared applications.
Near-distance imaging spectroscopy investigating chlorophyll fluorescence and photosynthetic activity of grassland in the daily course
Authors: Ač Alexander , Malenovský Zbyněk , Hanuš Jan , Tomášková Ivana , Urban Otmar , Marek Michal V.
Published: November 2009

Detection of grassland canopy chlorophyll fluorescence (Chl-F) conducted with an imaging spectroradiometer provided evidence of potential remote sensing estimation of steady-state Chl-F (Chl-Fs). Daily near-nadir views of extremely high spatial resolution hyperspectral images were acquired from a distance of 4 m for temperate montane grassland in the Czech Republic. Simultaneously, measurements of Chl-F and total chlorophyll content (Chla + b) were made on a single leaf at ground level were collected. A specifically designed ‘shade removal’ experiment revealed the influence of dynamic physiological plant processes on hyperspectral reflectance of three wavelengths: 532, 686 and 740 nm. Based on this information, the vegetation indexes R686/R630, R740/R800 and PRI calculated as (R532–R570)/(R532+R570) were tested for statistical significance with directly measured Chl-F parameters (maximum fluorescence yield, Fv/Fm; steady-state chlorophyll fluorescence, Chl-Fs and actual quantum yield, ФII). The grassland species under investigation were: Festuca rubra agg. (L.), Hieracium sp., Plantago sp., Nardus stricta (L.) and Jacea pseudophrygia (C.A. Meyer). The coefficients of determination (R2) for best-fit relationships between PRI-ФII and PRI-Chl-Fs, measured in the daily course, show a high variability of 0.23–0.78 and 0.20–0.65, respectively. Similarly, R2 for the R686/R630-ФII and R686/R630-Chl-Fs relationships varied between 0.20–0.73 and 0.41–0.70, respectively. The highest average R2 values were found between PRI and Chla + b (0.63) and R686/R630 and Chla + b (0.72). The ratio R740/R800 did not yield a statistically significant relation with Chl-F parameters.
Evolution of models to support community and policy action with science: Balancing pastoral livelihoods and wildlife conservation in savannas of East Africa
Authors: Reid R. S. , Nkedianye D. , Said M. Y. , Kaelo D. , Neselle M. , Makui O. , Onetu L. , Kiruswa S. , Kamuaro N. Ole , Kristjanson P. , Ogutu J. , BurnSilver S. B. , Goldman M. J. , Boone R. B. , Galvin K. A. , Dickson N. M. , Clark W. C.
Published: November 2009

We developed a “continual engagement” model to better integrate knowledge from policy makers, communities, and researchers with the goal of promoting more effective action to balance poverty alleviation and wildlife conservation in 4 pastoral ecosystems of East Africa. The model involved the creation of a core boundary-spanning team, including community facilitators, a policy facilitator, and transdisciplinary researchers, responsible for linking with a wide range of actors from local to global scales. Collaborative researcher−facilitator community teams integrated local and scientific knowledge to help communities and policy makers improve herd quality and health, expand biodiversity payment schemes, develop land-use plans, and fully engage together in pastoral and wildlife policy development. This model focused on the creation of hybrid scientific−local knowledge highly relevant to community and policy maker needs. The facilitation team learned to be more effective by focusing on noncontroversial livelihood issues before addressing more difficult wildlife issues, using strategic and periodic engagement with most partners instead of continual engagement, and reducing costs by providing new scientific information only when deemed essential. We conclude by examining the role of facilitation in redressing asymmetries in power in researcher−community−policy maker teams, the role of individual values and character in establishing trust, and how to sustain knowledge-action links when project funding ends.
How blood-derived odor influences mate-choice decisions by a mosquito-eating predator
Authors: Cross Fiona R. , Jackson Robert R. , Pollard Simon D.
Published: November 2009

Evarcha culicivora(Araneae, Salticidae) feeds indirectly on vertebrate blood by choosing, as preferred prey, bloodcarrying female mosquitoes. Mutual mate-choice behavior is also pronounced in this species. Here we show that, whenE. culicivorafeeds indirectly on blood, it acquires a diet-related odor that makes it more attractive to the opposite sex. The mate-choice decisions of the adults of both sexes were investigated in a series of experiments based on comparing how long the test spider remained close to the odor of one source spider on one day and to the odor of a different source spider on the following day. Four different maintenance diets for source spiders were used in these experiments: bloodfed female mosquitoes (Culicidae,Anopheles gambiae ss), sugar-fed female mosquitoes, male mosquitoes, and lake flies (Chironomidae,Nilodorum brevibucca). Both sexes ofE. culicivoraspent more time close to the odor of opposite-sex conspecifics that had been on a diet of bloodfed mosquitoes (blood diet) instead of any of the three nonblood diets. Opposite-sex conspecifics that had been on a nonblood diet became more attractive once they were switched to a blood diet. That the attractive odor from blood dissipates was shown when spiders became less attractive once they were switched to a nonblood diet or subjected to a fast. However, there was no evident preference for the odor of a same-sex conspecific on a blood diet instead of a lake fly diet. These findings are discussed in the context of sexual selection and sensory exploitation.
Constructing the equilibrium ensemble of folding pathways from short off-equilibrium simulations
Authors: Noé Frank , Schütte Christof , Vanden-Eijnden Eric , Reich Lothar , Weikl Thomas R.
Published: November 2009

Characterizing the equilibrium ensemble of folding pathways, including their relative probability, is one of the major challenges in protein folding theory today. Although this information is in principle accessible via all-atom molecular dynamics simulations, it is difficult to compute in practice because protein folding is a rare event and the affordable simulation length is typically not sufficient to observe an appreciable number of folding events, unless very simplified protein models are used. Here we present an approach that allows for the reconstruction of the full ensemble of folding pathways from simulations that are much shorter than the folding time. This approach can be applied to all-atom protein simulations in explicit solvent. It does not use a predefined reaction coordinate but is based on partitioning the state space into small conformational states and constructing a Markov model between them. A theory is presented that allows for the extraction of the full ensemble of transition pathways from the unfolded to the folded configurations. The approach is applied to the folding of a PinWW domain in explicit solvent where the folding time is two orders of magnitude larger than the length of individual simulations. The results are in good agreement with kinetic experimental data and give detailed insights about the nature of the folding process which is shown to be surprisingly complex and parallel. The analysis reveals the existence of misfolded trap states outside the network of efficient folding intermediates that significantly reduce the folding speed.
HIV-1 Vif-mediated ubiquitination/degradation of APOBEC3G involves four critical lysine residues in its C-terminal domain
Authors: Iwatani Yasumasa , Chan Denise S. B. , Liu Lin , Yoshii Hiroaki , Shibata Junko , Yamamoto Naoki , Levin Judith G. , Gronenborn Angela M. , Sugiura Wataru
Published: November 2009

During coevolution with the host, HIV-1 developed the ability to hijack the cellular ubiquitin/proteasome degradation pathway to counteract the antiviral activity of APOBEC3G (A3G), a host cytidine deaminase that can block HIV-1 replication. Abrogation of A3G function involves the HIV-1 Vif protein, which binds A3G and serves as an adapter molecule to recruit A3G to a Cullin5-based E3 ubiquitin ligase complex. Structure-guided mutagenesis of A3G focused on the 14 most surface-exposed Lys residues allowed us to identify four Lys residues (Lys-297, 301, 303, and 334) that are required for Vif-mediated A3G ubiquitination and degradation. Substitution of Arg for these residues confers Vif resistance and restores A3G's antiviral activity in the presence of Vif. In our model, the critical four Lys residues cluster at the C terminus, opposite to the known N-terminal Vif-interaction region in the protein. Thus, spatial constraints imposed by the E3 ligase complex may be an important determinant in Vif-dependent A3G ubiquitination.
Adenovirus E3 MHC inhibitory genes but not TNF/Fas apoptotic inhibitory genes expressed in β cells prevent autoimmune diabetes
Authors: Horwitz Marshall S. , Efrat Shimon , Christen Urs , von Herrath Matthias G. , Oldstone Michael B. A.
Published: November 2009

To mimic events and molecules involved in type 1 insulin-dependent diabetes mellitus (T1D), we previously designed a transgenic (tg) mouse model where the viral nucleoprotein (NP) gene of lymphocytic choriomeningitis virus (LCMV) was expressed in the thymus to delete high affinity antiself (virus) T cells and in insulin-producing β cells of the islets of Langerhans. Such tg mice, termed RIP-LCMV, fail to spontaneously develop diabetes. In contrast, when these mice are challenged with LCMV, they develop diabetes as they display hyperglycemia, low to absent levels of pancreatic insulin, and abundant mononuclear cell infiltrates in the islets. However, expressing the adenovirus early region (E3) gene in β cells along with the LCMV transgene aborted the T1D. The present study utilizes this combined tg model (RIP LCMV × RIP E3) to define the requirement(s) of either pro-apoptotic TNF and Fas pathways or MHC class I up-regulation on β cells for virus-induced T1D. Inhibitors to either pathway (TNF/Fas or MHC class I) are encoded in the E3 gene complex. To accomplish this task either the E3 region encoding the inhibitors of TNF and Fas pathways or the region encoding gp-19, a protein that inhibits transport of MHC class I molecules out of the endoplasmic reticulum were deleted in the RIP LCMV × RIP E3 model. Thus only the gp-19 is required to abort the virus-induced T1D. In contrast, removal of TNF- and Fas-pathway inhibitory genes had no effect on E3-mediated prevention of T1D.
Long-range retrograde spread of LTP and LTD from optic tectum to retina
Authors: Du Jiu-lin , Wei Hong-ping , Wang Zuo-ren , Wong Scott T. , Poo Mu-ming
Published: November 2009

Neural activity can induce persistent strengthening or weakening of synapses, known as long-term potentiation (LTP) or long-term depression (LTD), respectively. As potential cellular mechanisms underlying learning and memory, LTP and LTD are generally regarded as synapse-specific “imprints” of activity, although there is evidence in vitro that LTP/LTD may spread to adjacent synapses. Here, we report that LTP and LTD induced in vivo at retinotectal synapses of
Xenopus
tadpoles undergo rapid long-range retrograde spread from the optic tectum to the retina, resulting in potentiation and depression of bipolar cell synapses on the dendrites of retinal ganglion cells, respectively. The retrograde spread of LTP and LTD required retrograde signaling initiated by brain-derived neurotrophic factor and nitric oxide in the tectum, respectively. Such bidirectional adjustment of the strength of input synapses in accordance to that of output synapses may serve to coordinate developmental refinement and learning functions of neural circuits.
The Parallax Worlds of the West–Eastern Divan Orchestra
Authors: Willson Rachel Beckles
Published: November 2009

The West–Eastern Divan Orchestra – founded in 1999 by Daniel Barenboim with the support of Edward W. Said in response to the Israel–Palestine conflict – brings together young Arabs, Jews and Spaniards for a workshop and concert tour every year. It displays a tension between repertoire (exclusively the Western classical tradition) and marketing (as an expression of inter-cultural dialogue). Drawing on fieldwork from 2006, the article analyses this tension as it evolves for players who shift repeatedly between the demands of Western orchestral playing and political discussion. It exposes the way the hierarchy of musical roles and the discourse elaborated around them create an environment that erases the political identities of players; and discusses the ways in which this environment is punctured at certain moments by a discursive or practical intervention, causing political allegiances to rise back to the surface explosively (only to be subsumed once again into music). Although the orchestra is set up to oppose the violence of war in the Middle East, it can be seen to contain its own disconcertingly coercive regime, one emerging from its hierarchical constitution with Barenboim as omnipotent leader, the professional ambitions of players, and the power that music can have in confounding the conceptual sphere.
An Analog VLSI Architecture for High Speed, Low Power Object Tracking
Authors: Habibi Mehdi , Sayedi Masoud
Published: November 2009

Using a two-dimension array of MOSFET switches, a robust, high speed object tracking CMOS sensor is presented. The edges of the image scene are extracted by the in-pixel differential comparators and a region (object) of interest, which is selected by the user, is segmented using the switch network. Tracking is performed by automatic reselection of the desired region. The proposed design presents less sensitivity to threshold adjustments compared to the binarization technique. The processing is mainly performed in analog domain, thus reducing dynamic power dissipation and making the chip ideal for low power applications. The sensor has been designed as a 50 × 50 pixel VLSI CMOS chip in the 0.6 μm technology. Features such as power dissipation, output latency, and operating frequency are reported.
Detection Capabilities of Randomly-Deployed Sensor Fields
Authors: Nelson Jill K. , Rowe Errol G. , Carter G. Clifford
Published: November 2009

Distributed sensor fields have recently gained popularity as a means for detecting intruders moving through a protected area of the ocean. We characterize the detection capabilities of a network of randomly-deployed sensors with varying sensing capabilities. We develop a framework for analytically approximating the probability that such a sensor field detects a constant course target moving through the region as a function of the number of sensors deployed and the statistical properties that govern the sensing range. Analytical and empirical results indicate that, when the total sensing area is fixed, a set of smaller distributed sensors can achieve significantly improved detection performance relative to a single large sensor. We also study the relationship between coverage of a region of interest and likelihood of detecting a constant course intruder moving through that region. We derive expressions for the average number of sensors required to achieve a prescribed likelihood of detection and level of coverage and conclude that detection and coverage are fundamentally different characterizations of the capabilities of a sensor field. In fact, the number of sensors required to achieve a particular detection level may be several orders of magnitude smaller than that required to achieve the same level of coverage.
Energy Efficient, Delay Sensitive, Fault Tolerant Wireless Sensor Network for Military Monitoring
Authors: Bekmezci Ilker , Alagöz Fatih
Published: November 2009

In this article, a new TDMA based wireless sensor network (WSN), MILMON, is proposed for military monitoring. The most important design considerations of MILMON are energy consumption, delay, scalability, and fault tolerance. There are three main components of the system: a new time synchronization schema based on the sink with a high range transmitter, hr-FTSP; data indicator slot mechanism, DISM; and a new distributed time-scheduling mechanism ft_DTSM. An analytic and simulation model has shown that energy consumption and delay performance of the newly proposed system is better than most of the existing WSN systems. Although there may be other architectures which perform better than our system for certain performance metrics, MILMON can operate with a good balance on energy consumption, delay, and fault tolerance.
Adaptive Distributed Fair Scheduling for Multiple Channels in Wireless Sensor Networks
Authors: Fonda James W. , Zawodniok Maciej , Jagannathan S. , Watkins Steve E.
Published: November 2009

A novel adaptive and distributed fair scheduling (ADFS) scheme for wireless sensor networks (WSN) in the presence of multiple channels (MC-ADFS) is developed. The proposed MC-ADFS increases available network capacity and focuses on quality-of-service (QoS) issues. When nodes access a shared channel, the proposed MC-ADFS allocates the channel bandwidth proportionally to the packet's weight which indicates the priority of the packet's flow. The packets are dynamically assigned to channels based on the packet weight and current channel utilization. The dynamic assignment of channels is facilitated by use of receiver-based allocation and alternative routes. Moreover, MC-ADFS allows the dynamic allocation of network resources with little added overhead. Packet weights are initially assigned using user specified QoS criteria, and subsequently updated as a function of delay and queued packets. The back-off interval is also altered using the weight adaptation. The weight update and back-off interval selection ensure global fairness is attained even with variable service rates.
The effects of real versus hypothetical reward on delay and probability discounting
Authors: Hinvest Neal S. , Anderson Ian M.
Published: November 2009

Delay discounting and probability discounting tasks providing hypothetical rewards have commonly been used to measure levels of impulsivity and risk taking. Results have been inconsistent as to whether real, compared with hypothetical, rewards influence choice behaviour in delay discounting tasks. This experiment examined choice behaviour in 38 healthy individuals using delay and probability discounting tasks involving both real and hypothetical rewards (£0.10/£0.20), real delays, and probabilistic outcomes. It was hypothesized that choice behaviour when receiving real rewards would be less impulsive and less risky than when receiving hypothetical rewards. The tasks were designed so that a mathematical model (the multiplicative hyperbolic model of choice) could be applied to assess effects on discounting parameters. The provision of real rewards was associated with significantly decreased impulsive, but not risky, choice although the size of effect was small and was influenced by the order of presentation. Repeated presentation of both tasks increased quantity discounting but not delay or probability discounting parameters. These results indicate that the nature of the reward provided, and repetition effects, need to be taken into account when designing discounting studies.
Functional Explanation in Context
Authors: Couch Mark
Published: November 2009

The claim that a functional kind is multiply realized is typically motivated by appeal to intuitive examples. We are seldom told explicitly what the relevant structures are, and people have often preferred to rely on general intuitions in these cases. This article deals with the problem by explaining how to understand the proper relation between structural kinds and the functions they realize. I will suggest that the structural kinds that realize a function can be properly identified by attending to the context of functional explanation.
Epistemic Landscapes and the Division of Cognitive Labor
Authors: Weisberg Michael , Muldoon Ryan
Published: November 2009

Because contemporary scientific research is conducted by groups of scientists, understanding scientific progress requires understanding this division of cognitive labor. We present a novel agent-based model of scientific research in which scientists divide their labor to explore an unknown epistemic landscape. Scientists aim to find the most epistemically significant research approaches. We consider three different search strategies that scientists can adopt for exploring the landscape. In the first, scientists work alone and do not let the discoveries of the community influence their actions. This is compared with two social research strategies: Followers are biased toward what others have already discovered, and we find that pure populations of these scientists do less well than scientists acting independently. However, pure populations of mavericks, who try to avoid research approaches that have already been taken, vastly outperform the other strategies. Finally, we show that, in mixed populations, mavericks stimulate followers to greater levels of epistemic production, making polymorphic populations of mavericks and followers ideal in many research domains.
Marine reserves and the evolutionary effects of fishing on size at maturation
Authors: Miethe Tanja , Dytham Calvin , Dieckmann Ulf , Pitchford Jonathan W.
Published: November 2009

Miethe, T., Dytham, C., Dieckmann, U., and Pitchford, J. W. 2010. Marine reserves and the evolutionary effects of fishing on size at maturation. – ICES Journal of Marine Science, 67: 412–425. Size-selective fishing may induce rapid evolutionary changes in life-history traits such as size at maturation. A major concern is that these changes will reduce population biomass and detrimentally affect yield and recruitment. Although marine reserves have been proposed as a tool for fisheries management, their evolutionary implications have as yet attracted little scrutiny. A simple model is used to investigate whether marine reserves can be expected to mitigate the evolutionary impacts of fishing on maturation size. The adaptive dynamics of size at maturation are analysed based on a stage-structured population model including size-selective fishing and marine reserves with different retention rates. As has been shown before, imposing greater fishing mortality on the largest individuals promotes an evolutionary change towards smaller maturation size. In the model, protecting part of a fish stock using a marine reserve can prevent such fisheries-induced evolution, and this protection critically depends on the type and extent of movement between the reserve and the fished area. Specifically, although the frequent movement of large adults increases catches of large adult fish outside a marine reserve, it also reduces the reserve's effectiveness in preventing fisheries-induced evolution. In contrast, when there is exchange between protected and fished areas through juvenile export alone, a marine reserve can effectively prevent evolution towards smaller maturation size, but does so at the expense of reducing the yield of large adult fish. Differences in the movement behaviour of successive life stages need to be considered for marine reserves, to help make fisheries more sustainable evolutionarily.
Effects of Impact Dehuller Rotor Speed on Dehulling Characteristics of Diverse Oat Genotypes Grown in Different Environments
Authors: Doehlert D. C. , Wiesenborn D. P. , McMullen M. S. , Ohm J.‐B. , Riveland N. R.
Published: November 2009

Commercial processing of oats for human consumption generally requires impact dehulling to isolate groats from the hull. Impact dehulling involves feeding oat grain into the center of a spinning rotor that expels the grain against the walls of the dehuller. The force of the impact breaks the hull from the groat. We have tested the effect of rotor speed on dehulling efficiency, groat breakage, and unbroken groat yield on 18 oat genotypes from replicated plots in six different environments. Dehulling efficiency and groat breakage increased with rotor speed with all genotypes and environments, but there were significant genotypic and environmental effects as well. In general, genotypes with higher test weight and kernel density dehulled more efficiently at slower rotor speeds. Oat genotypes with higher oil and protein concentrations in their groats tended to break less during dehulling. Oats from hotter, drier environments suffered greater groat breakage. Maximal unbroken groat yield represented a balance between dehulling efficiency and groat breakage, but groat proportion and dehulling efficiency appeared to be the most important factors contributing to groat yield.
Triacylglyceride Metabolism by Fusarium graminearum During Colonization and Sexual Development on Wheat
Authors: Guenther John C. , Hallen-Adams Heather E. , Bücking Heike , Shachar-Hill Yair , Trail Frances
Published: November 2009

Fusarium graminearum, a devastating pathogen of small grains, overwinters on crop residues and produces ephemeral perithecia. Accumulation of lipids in overwintering hyphae would provide reserves for overwinter survival and perithecium development. Fatty acid composition of cultures during perithecium development indicated a drop in neutral lipid levels during development but little change in fatty acid composition across stages. Microscopic examination of cultures early in sexual development revealed hyphal cells engorged with lipid bodies. In comparison, vegetative hyphae contained few lipid bodies. Microarray analysis was performed on wheat stems at stages of colonization through perithecium development. Gene expression analysis during stages of perithecium development both in planta and in vitro (previously published) supports the view that lipid biosynthesis occurs during early stages of wheat colonization leading to sexual development and that lipid oxidation occurs as perithecia are developing. Analysis of gene expression during the stages of wheat stem colonization also revealed sets of genes unique to these stages. These results support the view that lipids accumulate in hyphae colonizing wheat stalks and are subsequently used in perithecium formation on stalk tissue. These results indicate that extensive colonization of plant tissue prior to harvest is essential for subsequent sporulation on crop residues and, thus, has important implications for inoculum reduction.
Comparative Analysis of Expression Profiles in Shoots and Roots of Tomato Systemically Infected byTomato spotted wilt virusReveals Organ-Specific Transcriptional Responses
Authors: Catoni Marco , Miozzi Laura , Fiorilli Valentina , Lanfranco Luisa , Accotto Gian Paolo
Published: November 2009

Tomato (Solanum lycopersicon), a model species for the family Solanaceae, is severely affected by Tomato spotted wilt virus (TSWV) worldwide. To elucidate the systemic transcriptional response of plants to TSWV infection, microarray experiments were performed on tomato. Parallel analysis of both shoots and roots revealed organ-specific responses, although the virus was present in similar concentration. In the shoots, genes related to defense and to signal transduction were induced, while there was general repression of genes related to primary and secondary metabolism as well as to amino acid metabolism. In roots, expression of genes involved in primary metabolism and signal transduction appear unaffected by TSWV infection, while those related to the response to biotic stimuli were induced and those associated to the response to abiotic stress were generally repressed or unaltered. Genes related to amino acid metabolism were unaffected, except for those involved in synthesis of secondary compounds, where induction was evident. Differential expression of genes involved in metabolism and response to ethylene and abscisic acid was observed in the two organs. Our results provide new insight into the biology of the economically important interaction between tomato and TSWV.
Plastocyanin Transit Peptide Interacts withPotato virus XCoat Protein, While Silencing of Plastocyanin Reduces Coat Protein Accumulation in Chloroplasts and Symptom Severity in Host Plants
Authors: Qiao Y. , Li H. F. , Wong S. M. , Fan Z. F.
Published: November 2009

Potato virus X coat protein (PVXCP) is, through communication with host proteins, involved in processes such as virus movement and symptom development. Here, we report that PVXCP also interacts with the precursor of plastocyanin, a protein involved in photosynthesis, both in vitro and in vivo. Yeast two-hybrid analysis indicated that PVXCP interacted with only the plastocyanin transit peptide. In subsequent bimolecular fluorescence complementation assays, both proteins were collocated within chloroplasts. Western blot analyses of chloroplast fractions showed that PVXCP could be detected in the envelope, stroma, and lumen fractions. Transmission electron microscopy demonstrated that grana were dilated in PVX-infected Nicotiana benthamiana. Furthermore, virus-induced gene silencing of plastocyanin by prior infection of N. benthamiana using a Tobacco rattle virus vector reduced the severity of symptoms that developed following subsequent PVX infection as well as the accumulation of PVXCP in isolated chloroplasts. However, PVXCP could not be detected in pea chloroplasts in an in vitro re-uptake assay using the plastocyanin precursor protein. Taken together, these data suggest that PVXCP interacts with the plastocyanin precursor protein and that silencing the expression of this protein leads to reduced PVXCP accumulation in chloroplasts and ameliorates symptom severity in host plants.