bluuebunny/crossref_metadata_2025 huggingface dataset:
The Mutual Influence of Gaze and Head Orientation in the Analysis of Social Attention Direction
Authors: Langton Stephen R. H.
Published: September 2011

Three experiments are reported that investigate the hypothesis that head orientation and gaze direction interact in the processing of another individual's direction of social attention. A Stroop-type interference paradigm was adopted, in which gaze and head cues were placed into conflict. In separate blocks of trials, participants were asked to make speeded keypress responses contingent on either the direction of gaze, or the orientation of the head displayed in a digitized photograph of a male face. In Experiments 1 and 2, head and gaze cues showed symmetrical interference effects. Compared with congruent arrangements, incongruent head cues slowed responses to gaze cues, and incongruent gaze cues slowed responses to head cues, suggesting that head and gaze are mutually influential in the analysis of social attention direction. This mutuality was also evident in a cross-modal version of the task (Experiment 3) where participants responded to spoken directional words whilst ignoring the head/gaze images. It is argued that these interference effects arise from the independent influences of gaze and head orientation on decisions concerning social attention direction.
The Teco Theory and Lawful Dependency in Successive Episodic Memory Tests
Authors: Sikström Sverker
Published: September 2011

A large number of experiments in successive tests of episodic memory have focused on an experimental paradigm called recognition failure of recallable words. In this paradigm, a cued recall test follows a recognition test. Large amounts of data have revealed a lawful moderate dependence between recognition and cued recall. TECO (Sikström, 1996b), a general connectionist theory of memory, has been applied for the phenomenon of recognition failure. This paper makes a strong claim that all possible pairwise combinations of successive tests between recognition, cued recognition, cued recall, and free recall follow a lawful relationship. The quantitative degree of the dependency predicted between these tests can be summarized in one function. Four experiments were conducted to test this claim. In line with the predictions, the results show that all pairwise combinations of these tests fit reasonably well with the proposed function. The TECO theory suggests theoretical insights into how recognition and recall may be divided into a recollection component, a familiarity component, and a cue-target integration component.
The Effects of Divided Attention on Encoding and Retrieval Processes: The Resiliency of Retrieval Processes
Authors: Naveh-Benjamin Moshe , Craik Fergus I. M. , Perretta James G. , Tonev Simon T.
Published: September 2011

We have recently cast doubt (Craik, Govoni, Naveh-Benjamin, & Anderson, 1996; Naveh-Benjamin, Craik, Guez, & Dori, 1998) on the view that encoding and retrieval processes in human memory are similar. Divided attention at encoding was shown to reduce memory performance significantly, whereas divided attention at retrieval affected memory performance only minimally. In this article we examined this asymmetry further by using more difficult retrieval tasks, which require substantial effort. In one experiment, subjects had to encode and retrieve lists of unfamiliar name-nouns combinations attached to people's photographs, and in the other, subjects had to encode words that were either strong or weak associates of the cues presented with them and then to retrieve those words with either intra- or extra-list cues. The results of both experiments showed that unlike division of attention at encoding, which reduces memory performance markedly, division of attention at retrieval has almost no effect on memory performance, but was accompanied by an increase in secondary-task cost. Such findings again illustrated the resiliency of retrieval processes to manipulations involving the withdrawal of attention. We contend that retrieval processes are obligatory or protected, but that they require attentional resources for their execution.
On the Cognitive Basis of Observational Learning: Development of Mechanisms for the Detection and Correction of Errors
Authors: Blandin Yannick , Proteau Luc
Published: September 2011

It has been proposed that observation of a model practising a motor skill results in the observer developing mechanisms for the detection and correction of errors that are similar to those acquired during physical practice. Results of a first experiment indicated that prior observation of a model permitted participants to estimate their errors as efficiently as those who had physically practised the task. Similarly, results of a second experiment indicated that observation of a model receiving biased knowledge of results during practice resulted in similarly biased reference and error detection/correction mechanisms for the observers and for the models. These results suggest that observation engages one in cognitive processes similar to those occurring during physical practice.
Individual Differences in Memory Span: The Contribution of Rehearsal, Access to Lexical Memory, and Output Speed
Authors: Tehan Gerald , Lalor David M.
Published: September 2011

Rehearsal speed has traditionally been seen to be the prime determinant of individual differences in memory span. Recent studies, in the main using young children as the subject population, have suggested other contributors to span performance, notably contributions from long-term memory and forgetting and retrieval processes occurring during recall. In the current research we explore individual differences in span with respect to measures of rehearsal, output time, and access to lexical memory. We replicate standard short-term phenomena; we show that the variables that influence children's span performance influence adult performance in the same way; and we show that lexical memory access appears to be a more potent source of individual differences in span than either rehearsal speed or output factors.
The Effect of Clause Wrap-Up on Eye Movements during Reading
Authors: Rayner Keith , Kambe Gretchen , Duffy Susan A.
Published: September 2011

The effect of clause wrap-up on eye movements in reading was examined. Readers read passages in which a target category noun referred to either a high typical or a low typical antecedent. In addition, the category noun was either clause final or non-clause final. There were four primary results: (1) Readers looked longer at a category noun when its antecedent was a low typical member of the category than when it was a high typical member; (2)readers looked longer at the category noun and at the post-category region when they were clause final than when they were not clause final; (3) readers regressed from a category noun or post-category region more frequently when it was clause final than when it was not clause final; and (4) readers made longer initial saccades when their eyes left the category noun or post-category region when this word was in clause final position than when it was not clause final. The last result suggests that sometimes higher order processes that are related to making a decision about when to move the eyes impinge on lower level decisions that are typically associated with deciding where to move the eyes.
Tests of the Ratio Rule in Categorization
Authors: Wills A.J. , Reimers Stian , Stewart Neil , Suret Mark , McLaren I.P.L.
Published: September 2011

Many theories of learning and memory (e.g., connectionist, associative, rational, exemplar based) produce psychological magnitude terms as output (i.e., numbers representing the momentary level of some subjective property). Many theories assume that these numbers may be translated into choice probabilities via the ratio rule, also known as the choice axiom (Luce, 1959) or the constant-ratio rule (Clarke, 1957). We present two categorization experiments employing artificial, visual, prototype-structured stimuli constructed from 12 symbols positioned on a grid. The ratio rule is shown to be incorrect for these experiments, given the assumption that the magnitude terms for each category are univariate functions of the number of category-appropriate symbols contained in the presented stimulus. A connectionist winner-take-all model of categorical decision (Wills & McLaren, 1997) is shown to account for our data given the same assumption. The central feature underlying the success of this model is the assumption that categorical decisions are based on a Thurstonian choice process (Thurstone, 1927, Case V) whose noise distribution is not double exponential in form.
A Small-to-Large Unit Progression in Metaphonological Awareness and Reading?
Authors: uncan Lynne G.D , Seymour Philip H.K. , Hill Shirley
Published: September 2011

The paper reports a series of studies of reading and metaphonological processing by children in their second year in primary school(aged 6 years). An earlier study had established that, in the first year of learning, performance was characterized by a small-unit approach in which graphemes and phonemes were emphasized. In the second year, reading became more sensitive to the frequencies of rime structures in the lexicon. Capacity to generate word analogies for nonwords also showed increasing commitment to rime-based responses, and this trend was strongly linked to reading age. The present results suggest that a small-unit approach to reading is augmented by a large-unit approach as development proceeds. This trend was reflected in performance on a test of explicit phonological awareness. When asked to report the segment of sound shared by two spoken words, Primary 1 children were poor in reporting shared rimes but relatively adept in reporting shared phonemes. During Primary 2 there was an improvement in ability to report shared rimes, and this trend was also related to reading age. These results are discussed in relation to the influence of instruction and the nature of the orthography in determining the course of reading development.
The Suppression of q Card Selections: Evidence for Deductive Inference in Wason's Selection Task
Authors: Feeney Aidan , Handley Simon J.
Published: September 2011

The results of three experiments investigating the role of deductive inference in Wason's selection task are reported. In Experiment 1, participants received either a standard one-rule problem or a task containing a second rule, which specified an alternative antecedent. Both groups of participants were asked to select those cards that they considered were necessary to test whether the rule common to both problems was true or false. The results showed a significant suppression of q card selections in the two-rule condition. In addition there was weak evidence for both decreased p selection and increased not-q selection. In Experiment 2 we again manipulated number of rules and found suppression of q card selections only. Finally, in Experiment 3 we compared one- and two-rule conditions with a two-rule condition where the second rule specified two alternative antecedents in the form of a disjunction. The q card selections were suppressed in both of the two-rule conditions but there was no effect of whether the second rule contained one or two alternative antecedents. We argue that our results support the claim that people make inferences about the unseen side of the cards when engaging with the indicative selection task.
Working Memory, Metacognitive Uncertainty, and Belief Bias in Syllogistic Reasoning
Authors: Quayle Jeremy D. , Ball Linden J.
Published: September 2011

Studies of syllogistic reasoning have shown that the size of the belief bias effect varies with manipulations of logical validity and problem form. This paper presents a mental models-based account, which explains these findings in terms of variations in the working-memory demands of different problem types. We propose that belief bias may reflect the use of a heuristic that is applied when a threshold of uncertainty in one's processing—attributable to working-memory overload-is exceeded during reasoning. Three experiments are reported, which tested predictions deriving from this account. In Experiment 1, conclusions of neutral believability were presented for evaluation, and a predicted dissociation was observed in confidence ratings for responses to valid and invalid arguments, with participants being more confident in the former. In Experiment 2, an attempt to manipulate working-memory loads indirectly by varying syllogistic figure failed to produce predicted effects upon the size of the belief bias effect. It is argued that the employment of a conclusion evaluation methodology minimized the effect of the figural manipulation in this experiment. In Experiment 3, participants’ articulatory and spatial recall capacities were calibrated as a direct test of working-memory involvement in belief bias. Predicted differences in the pattern of belief bias observed between high and low spatial recall groups supported the view that limited working memory plays a key role in belief bias.
Does Sunshine Prime Loyal? Affective Priming in the Naming Task
Authors: Klauer Karl Christoph , Musch Jochen
Published: September 2011

Recent work has found an affective priming effect using the naming task: In pronouncing target words, pronunciation latencies were consistently shorter when the target (e.g., loyal) was preceded by an evaluatively congruent (e.g., sunshine) rather than incongruent prime word (e.g, rain). Using the naming task, no affective priming was found in the present studies irrespective of prime-set size and target-set size (Experiment 1), irrespective of stimulus-onset asynchrony (Experiment 2), and even when a nearly exact replication of previous work that demonstrated the effect was conducted (Experiment 3). Finally, bilingual German/English speakers exhibited strong associative priming, but no affective priming, in both the English as well as the German language (Experiment 4). The results show that priming for evaluatively related words is not a general finding.
Response-Time Dynamics: Evidence for Linear and Low-Dimensional Nonlinear Structure in Human Choice Sequences
Authors: Kelly Alice , Heathcote Andrew , Heath Richard , Longstaff Mitchell
Published: September 2011

Response time (RT) is a commonly used measure of cognitive performance, which is usually characterized as stochastic. However, useful information may be hidden in the apparently random fluctuations of RT. Dynamical systems analysis techniques allow an exploration of the alternative hypothesis that RT fluctuations are deterministic, albeit in a complex manner. We applied careful task construction and noise-reduction and surrogate series tests to show that RT series from a forced-pace serial response-time task have low-dimensional chaotic characteristics. In Experiment 1, 80% of subjects’ filtered RT series had low dimensionality, sensitive dependence on initial conditions, spectra close to 1/ f, and stable attractor geometry across sessions. In Experiment 2, we showed that the size of the inter-stimulus interval (ISI) determined the number of subjects with low-dimensional chaotic series. A small ISI caused 100% of subjects to respond in the chaotic regime, whereas only 25% had a low-dimensional chaotic RT component when the ISI was large. We argue that demanding task requirements cause a reduction in the dimensionality of the dynamics, producing RT fluctuations that may reflect a response strategy for controlling RT.
Cued Shifts of Attention and Memory Encoding in Partial Report: A Dual-Task Approach
Authors: Giesbrecht Barry , Dixon Peter , Kingstone Alan
Published: September 2011

This study explores how cued shifts of visual attention and rapid encoding of visual information relate to limited-capacity processing mechanisms. Three experiments were conducted placing a partial-report task within a dual-task paradigm. Experiments 1 and 2 involved a simple speeded visual discrimination (Task 1) and then an unspeeded partial-report task (Task 2). Generally, Task 2 accuracy declined as the temporal overlap between the two tasks increased. In addition, in Experiment 1, varying the number of items in the partial-report display had an effect on performance regardless of overlap. In contrast, in Experiment 2, varying the type of probe had an effect only at long task overlap. The generality of the interference effect was tested in Experiment 3 using an auditory discrimination as Task 1. Again, Task 2 accuracy declined as the temporal overlap between the two tasks increased. In all cases, the observed interference had the properties of a processing bottleneck. It is argued that encoding information into memory and response selection for the first task both require general-purpose processing. The results are discussed in terms of the functional relationship between attention and memory.
Understanding Microworlds
Authors: Green David W.
Published: September 2011

Little is known about how individuals understand change in complex systems. In the natural world, for instance, the effects of change need to be understood in terms of two-way (interdependent) causal processes. Based on subject's ratings of the causal likelihood that a given change will yield a target effect and on subjects’ ratings of the impact of a given change on specified populations in a microworld, White (1997, 2000) argued that individuals in fact understand change in terms of one-way causal processes and assume that causal effects decline with distance from the source of the change. An alternative view is that the ratings reflect individuals’ mental simulations of change as elicited by the tasks. Experiments 1 and 2 confirm that such ratings are task dependent and that individuals make no general assumption that causal effects decrease with distance. Experiment 3 shows that when required to explain a pattern of change in the size of a population individuals can construct two-way causal explanations consistent with this mental simulation proposal.
What colour is the car? Implicit memory for colour information in children
Authors: Mecklenbräuker Silvia , Hupbach Almut , Wippich Werner
Published: September 2011

Three experiments were conducted to examine age-related differences in colour memory. In Experiment 1, preschool age and elementary school age children were given a conceptual test of implicit colour memory (a colour-choice task). They were presented with the names or achromatic versions of previously studied coloured line drawings and asked to select an appropriate colour. Significant priming could be demonstrated: The children chose the previously seen colours more often than was expected by chance. Equivalent priming was found for both versions (pictorial and verbal) suggesting that colour priming may be conceptually mediated. Moreover, colour priming proved to be age invariant. Experiment 2 replicated and extended this finding by using a wider age group (preschool, elementary school, and young adults) and by giving a perceptual implicit task (picture identification) in addition to a verbal colour-choice task. Colour did not affect priming in the perceptual task. Whereas priming showed no developmental change, age related improvements were observed on an explicit colour memory task that differed only in the test instructions from the implicit colour-choice task (Experiments 2 and 3). Taken together, the results suggest that implicit colour memory may be mediated by conceptual processes that are age invariant.
Storage and retrieval of addition facts: The role of number comparison
Authors: Butterworth Brian , Zorzi Marco , Girelli Luisa , Jonckheere A.R.
Published: September 2011

It is proposed that arithmetical facts are organized in memory in terms of a principle that is unique to numbers—the cardinal magnitudes of the addends. This implies that sums such as 4 + 2 and 2 + 4 are represented, and searched for, in terms of the maximum and minimum addends. This in turn implies that a critical stage in solving an addition problem is deciding which addend is the larger. The COMP model of addition fact retrieval incorporates a comparison stage, as well as a retrieval stage and a pronunciation stage. Three tasks, using the same subjects, were designed to assess the contribution of these three stages to retrieving the answers to single-digit addition problems. Task 3 was the addition task, which examined whether reaction times (RTs) were explained by the model; Task 1 was a number naming task to assess the contribution of the pronunciation stage; Task 2 was a magnitude comparison task to assess the contribution, if any, of the comparison stage. A regression equation that included just expressions of these three stages was found to account for 71% of the variance. It is argued that the COMP model fits not only the adult RT data better than do alternatives, but also the evidence from development of additional skills.
Inhibition of return at multiple locations in visual search: When you see it and when you don't
Authors: Snyder Janice J. , Kingstone Alan
Published: September 2011

Using a novel sequential task, Danziger, Kingstone, and Snyder (1998) provided conclusive evidence that inhibition of return (IOR) can co-occur at multiple non-contiguous locations. They argued that their findings depended crucially on the allocation of attention to cued locations. Specifically, they hypothesized that because subjects could not predict whether an onset event was a target or a non-target, all onset events had to be attended. As a result, non-targets were tagged with inhibition. The present study tested this hypothesis by manipulating whether target onset was predictable or not. In support of Danziger et al., three experiments revealed that multiple IOR was only observed when attention had to be directed to the cued locations. Interestingly, when attention did not need to be allocated to the cued locations, and multiple IOR was abolished, an IOR effect was still observed at the most recently cued location. Two possible accounts for this single IOR effect were presented for future investigation. One account attributes the effect to motor-based inhibition as hypothesized by Klein and Taylor (1994). The alternative account attributes the effect to weak attentional capture by a peripheral cue. Together the data support the view that multiple IOR is an attentional phenomenon and, as hypothesized by Tipper, Weaver, and Watson (1996), its presence or absence is largely under the control of the observer.
The automaticity of complex motor skill learning as a function of attentional focus
Authors: Wulf Gabriele , McNevin Nancy , Shea Charles H.
Published: September 2011

The present experiment was designed to test the predictions of the constrained-action hypothesis. This hypothesis proposes that when performers utilize an internal focus of attention (focus on their movements) they may actually constrain or interfere with automatic control processes that would normally regulate the movement, whereas an external focus of attention (focus on the movement effect) allows the motor system to more naturally self-organize. To test this hypothesis, a dynamic balance task (stabilometer) was used with participants instructed to adopt either an internal or external focus of attention. Consistent with earlier experiments, the external focus group produced generally smaller balance errors than did the internal focus group and responded at a higher frequency indicating higher confluence between voluntary and reflexive mechanisms. In addition, probe reaction times (RTs) were taken as a measure of the attention demands required under the two attentional focus conditions. Consistent with the hypothesis, the external focus participants demonstrated lower probe RTs than did the internal focus participants, indicating a higher degree of automaticity and less conscious interference in the control processes associated with the balance task.
Low current density induced spin-transfer torque switching in CoFeB–MgO magnetic tunnel junctions with perpendicular anisotropy
Authors: Meng H , Sbiaa R , Lua S Y H , Wang C C , Akhtar M A K , Wong S K , Luo P , Carlberg C J P , Ang K S A
Published: September 2011

We present the thickness effects of CoFeB free layer on tunnelling magnetoresistive (TMR), perpendicular magnetic anisotropy (PMA) and spin-transfer torque (STT) in CoFeB–MgO based magnetic tunnel junctions (MTJs). It is found that a post-annealing process could significantly improve both TMR and PMA of the MTJ systems. When the free layer thickness is reduced from 1.3 nm to 1 nm, TMR continuously decays from 80% to 20%. On the other hand, PMA is maximized for a 1.28 nm free layer, above which demagnetization becomes stronger and results in lower PMA. If the free layer thickness is very small, dead layer effect could damage interfacial perpendicular anisotropy and PMA is reduced as a consequence. For STT-induced magnetization switching, the lowest intrinsic critical switching current density (J
c0) of 2.1 MA cm−2 is achieved at a free layer thickness of 1.16 nm, accompanied by a TMR of 52% and product of resistance and area (RA) of 16 Ω µm2. Further increasing the free layer thickness will first enhance J
c0 and then reduce it due to the balance between PMA and the total free layer volume. STT studies suggest that the CoFeB free layer thickness should be optimized to make a trade-off among large PMA, high TMR and low switching current density in perpendicular CoFeB–MgO MTJ systems.
Comparative study of CNT, silicon nanowire and fullerene embedded multilayer high-k gate dielectric MOS memory devices
Authors: Sengupta Amretashis , Sarkar Chandan Kumar , Requejo Felix G
Published: September 2011

Here, we present a comparative theoretical study on stacked (multilayer) gate dielectric MOS memory devices, having a metallic/semiconducting carbon nanotube (CNT), silicon nanowire (Si NW) and fullerene (C60) embedded nitride layer acting as a floating gate. Two types of devices, one with HfO2–SiO2 stack (stack-1) and the other with La2O3–SiO2 stack (stack-2) as the tunnel oxide were compared. We evaluated the effective barrier height, the dielectric constant and the effective electron mobility in the composite gate dielectric with the Maxwell–Garnett effective medium theory. Thereafter applying the WKB approximation, we simulated the Fowler–Nordheim (F–N) tunnelling/writing current and the direct tunnelling/leakage current in these devices. We evaluated the I–V characteristics, the charge decay and also the impact of CNT/Si NW aspect ratio and the volume fraction on the effective barrier height and the write voltage, respectively. We also simulated the write time, retention time and the erase time of these MOS devices. Based on the simulation results, it was concluded that the metallic CNT embedded stack-1 device offered the best performance in terms of higher F–N tunnelling current, lower direct tunnelling current and lesser write voltage and write time compared with the other devices. In case of direct tunnelling leakage and retention time it was found that the met CNT embedded stack-2 device showed better characteristics. For erasing, however, the C60 embedded stack-1 device showed the smallest erase time. When compared with earlier reports, it was seen that CNT, C60 and Si NW embedded devices all performed better than nanocrystalline Si embedded MOS non-volatile memories.
Dependence of dark current and photoresponse characteristics on polarization charge density for GaN-based avalanche photodiodes
Authors: Wang Xiaodong , Hu Weida , Chen Xiaoshuang , Xu Jintong , Wang Ling , Li Xiangyang , Lu Wei
Published: September 2011

GaN/AlGaN avalanche photodiodes (APD) are fabricated based on GaN/AlGaN materials of epitaxial growth. Dark current and photoresponse characteristics are shown experimentally and theoretically. The effects of polarization charge density (PCD) on the dark current of GaN/AlGaN APDs are investigated in detail. It is demonstrated that an increased PCD reduces the electric field intensity in the GaN i-region, and results in an increase in breakdown voltage and a decrease in dark current above 65 V reverse bias. However, it is indicated that increasing the PCD elevates the electric field intensity at the GaN/AlGaN interface, and thus induces an enhancement of the band-to-band tunnelling and trap-assisted tunnelling processes, and eventually an evident rise in the dark current below 50 V reverse bias. Additionally, the effects of PCD on the optical responsivity are studied in detail. Results show that positive polarization charge has little effect on the photoresponse of the device. However, the negative polarization charge significantly affects the photoresponse. A metal–oxide–semiconductor inversion layer model has been proposed to explain the effect of negative polarization charge on photoresponse.
Wide bandgap n-type and p-type semiconductor porous junction devices as photovoltaic cells
Authors: Lin Yuan-Pai , Chao Yu-Chiang , Meng Hsin-Fei , Zan Hsiao-Wen , Horng Sheng-Fu
Published: September 2011

In junction absorber photovoltaics doped wide bandgap n-type and p-type semiconductors form a porous interpenetrating junction structure with a layer of low bandgap absorber at the interface. The doping concentration is high enough such that the junction depletion width is smaller than the pore size. The highly conductive neutral region then has a dentrite shape with fingers reaching the absorber to effectively collect the photo-carriers swept out by the junction electric field. With doping of 1019 cm−3 corresponding to a depletion width of 25 nm, pore size of 32 nm, absorber thickness close to exciton diffusion length of 17 nm, absorber bandgap of 1.4 eV and carrier mobility over 10−5 cm2 V−1 s−1, numerical calculation shows the power conversion efficiency is as high as 19.4%. It rises to 23% for a triplet exciton absorber.
Design and analysis of a low-loss terahertz directional coupler based on three-core photonic crystal fibre configuration
Authors: Chen Ming-Yang , Fu Xiao-Xia , Zhang Yong-Kang
Published: September 2011

A novel kind of terahertz directional optical fibre coupler is proposed. The coupling characteristics and operation bandwidth of the three-core photonic crystal fibre coupler are investigated. Numerical results show that it is possible to achieve a broadband terahertz fibre coupler with a small fibre length of a few centimetres. In addition, a modified configuration, which can achieve a wider bandwidth and lower absorption loss, is proposed.
Strength of ultrananocrystalline diamond controlled by friction of buried interfaces
Authors: Mo Yifei , Stone Donald , Szlufarska Izabela
Published: September 2011

Grain boundary (GB) plasticity plays a critical role in deformation of nanocrystalline (NC) materials. However, it has been unclear how strength of these materials depends on GB properties. We use ultrananocrystalline diamond (UNCD) as a model material in which the plastic deformation is mainly located at the GBs and the dislocation processes are not active. We discover that hardness and yield stress have a simple functional dependence on the stress required for GB sliding. Our results on hydrogenated UNCD demonstrate that phenomena from the field of nanoscale friction can be utilized to understand the deformation of NC materials.
Bypass of glycan-dependent glycoprotein delivery to ERAD by up-regulated EDEM1
Authors: Ron Efrat , Shenkman Marina , Groisman Bella , Izenshtein Yana , Leitman Julia , Lederkremer Gerardo Z.
Published: September 2011

Trimming of mannose residues from the N-linked oligosaccharide precursor is a stringent requirement for glycoprotein endoplasmic reticulum (ER)-associated degradation (ERAD). In this paper, we show that, surprisingly, overexpression of ER degradation–enhancing α-mannosidase-like protein 1 (EDEM1) or its up-regulation by IRE1, as occurs in the unfolded protein response, overrides this requirement and renders unnecessary the expression of ER mannosidase I. An EDEM1 deletion mutant lacking most of the carbohydrate-recognition domain also accelerated ERAD, delivering the substrate to XTP3-B and OS9. EDEM1 overexpression also accelerated the degradation of a mutant nonglycosylated substrate. Upon proteasomal inhibition, EDEM1 concentrated together with the ERAD substrate in the pericentriolar ER-derived quality control compartment (ERQC), where ER mannosidase I and ERAD machinery components are localized, including, as we show here, OS9. We suggest that a nascent glycoprotein can normally dissociate from EDEM1 and be rescued from ERAD by reentering calnexin-refolding cycles, a condition terminated by mannose trimming. At high EDEM1 levels, glycoprotein release is prevented and glycan interactions are no longer required, canceling the otherwise mandatory ERAD timing by mannose trimming and accelerating the targeting to degradation.
Impacts of ocean acidification on development of the meroplanktonic larval stage of the sea urchin Centrostephanus rodgersii
Authors: Doo Steve S. , Dworjanyn Symon A. , Foo Shawna A. , Soars Natalie A. , Byrne Maria
Published: September 2011

Doo, S. S., Dworjanyn, S. A., Foo, S. A., Soars, N. A., and Byrne, M. 2012. Impacts of ocean acidification on development of the meroplanktonic larval stage of the sea urchin Centrostephanus rodgersii. – ICES Journal of Marine Science, 69: 460–464. The effects of near-future ocean acidification/hypercapnia on larval development were investigated in the sea urchin Centrostephanus rodgersii, a habitat-modifying species from eastern Australia. Decreased pH (−0.3 to −0.5 pH units) or increased pCO2 significantly reduced the percentage of normal larvae. Larval growth was negatively impacted with smaller larvae in the pH 7.6/1800 ppm treatments. The impact of acidification on development was similar on days 3 and 5, indicating deleterious effects early in development. On day 3, increased abnormalities in the pH 7.6/1600 ppm treatment were seen in aberrant prism stage larvae and arrested/dead embryos. By day 5, echinoplutei in this treatment had smaller arm rods. Observations of smaller larvae in C. rodgersii have significant implications for this species because larval success may be a potential bottleneck for persistence in a changing ocean.
Acquisition and Transmission of Peanut clump virus by Polymyxa graminis on Cereal Species
Authors: Dieryck Benjamin , Weyns Jeannine , Doucet Diane , Bragard Claude , Legrève Anne
Published: September 2011

The objective of this study was to investigate the specificity of the interactions between Polymyxa graminis, Peanut clump virus (PCV), and cereals, particularly the acquisition and the transmission of the virus by three P. graminis formae speciales. A new strategy has been developed: it involves using sugarcane as the common host for both the virus and its vector in order to produce the viruliferous zoospores of P. graminis f. sp. subtropicalis, temperata, and tropicalis that were then inoculated on cereal species. This experiment enabled the role of P. graminis f. sp. tropicalis and subtropicalis zoospores in PCV transmission to be demonstrated. The efficiency of this transmission was shown to vary, depending on the P. graminis special forms. Interestingly, the high transmission of the PCV isolate from Burkina Faso by an isolate of P. graminis f. sp. tropicalis from Niger on pearl millet suggests that there is a coevolution mechanism in this pathosystem. The study also provides evidence that the host plant species in which Polymyxa zoospores are produced could affect the infectivity of the vector. Finally, using Polymyxa quantitation by quantitative reverse-transcription polymerase chain reaction and in situ observations of the virus, the study demonstrates the independence of the development of PCV and its vector in the host plants.
Molecular Mapping of Hypersensitive Resistance from Tomato ‘Hawaii 7981’ toXanthomonas perforansRace T3
Authors: Wang Hui , Hutton Samuel F. , Robbins Matthew D. , Sim Sung-Chur , Scott Jay W. , Yang Wencai , Jones Jeffrey B. , Francis David M.
Published: September 2011

Bacterial spot of tomato (Solanum lycopersicum) is caused by four species of Xanthomonas. The disease causes significant yield losses and a reduction in fruit quality. Physiological races have been described with tomato race 3 (T3) corresponding to strains of Xanthomonas perforans. The breeding line Hawaii 7981 (hereafter H7981) shows a hypersensitive reaction (HR) to race T3 strains conditioned by the interaction of the host resistance locus Xv3 and the bacterial effector avrXv3. The Xv3 gene is required for H7981-derived resistance to be effective under field conditions, though its expression is subject to genetic background. The segregation of HR in F2populations derived from H7981 crossed to processing tomato parents OH88119 and OH7870 was studied in 331 progeny, with the two independent crosses providing validation. We screened 453 simple-sequence repeat, insertion/deletion, and single-nucleotide polymorphism markers and identified 44 polymorphic markers each for the OH88119 and OH7870 populations covering 84.6 and 73.3% of the genome, respectively, within 20 centimorgans (cM). Marker–trait analysis using all polymorphic markers demonstrated that Xv3-mediated resistance maps to chromosome 11 in the two independent crosses. Allelism tests were conducted in crosses between lines carrying Xv3 derived from H7981, Rx-4 derived from plant introduction (PI) 128216, and resistance derived from PI 126932. These allelism tests suggested that the loci conditioning HR to race T3 strains are linked within 0.1 cM, are allelic, or are the same gene.
Epstein–Barr virus Rta-mediated transactivation of p21 and 14-3-3σ arrests cells at the G1/S transition by reducing cyclin E/CDK2 activity
Authors: Huang Sheng-Yen , Hsieh Min-Jie , Chen Chu-Ying , Chen Yen-Ju , Chen Jen-Yang , Chen Mei-Ru , Tsai Ching-Hwa , Lin Su-Fang , Hsu Tsuey-Ying
Published: September 2011

Many herpesviral immediate-early proteins promote their robust lytic phase replications by hijacking the cell cycle machinery. Previously, lytic replication of Epstein–Barr virus (EBV) was found to be concurrent with host cell cycle arrest. In this study, we showed that ectopic expression of EBV immediate-early protein Rta in HEp-2 cells resulted in increased G1/S population, hypophosphorylation of pRb and decreased incorporation of 5-bromo-2′-deoxyuridine. In addition, EBV Rta transcriptionally upregulates the expressions of p21 and 14-3-3σ in HEp-2 cells, 293 cells and nasopharyngeal carcinoma TW01 cells. Although p21 and 14-3-3σ are known targets for p53, Rta-mediated p21 and 14-3-3σ transactivation can be detected in the absence of p53. In addition, results from luciferase reporter assays indicated that direct binding of Rta to either promoter sequences is not required for activation. On the other hand, a special class of Sp1-responsive elements was involved in Rta-mediated transcriptional activation on both promoters. Finally, Rta-induced p21 expression diminished the activity of CDK2/cyclin E complex, and, Rta-induced 14-3-3σ expression sequestered CDK1 and CDK2 in the cytoplasm. Based on these results, we hypothesize that through the disruption of CDK1 and CDK2 activities, EBV Rta might contribute to cell cycle arrest in EBV-infected epithelial cells during viral reactivation.
The C terminus of lettuce mosaic potyvirus cylindrical inclusion helicase interacts with the viral VPg and with lettuce translation eukaryotic initiation factor 4E
Authors: Tavert-Roudet G. , Abdul-Razzak A. , Doublet B. , Walter J. , Delaunay T. , German-Retana S. , Michon T. , Le Gall O. , Candresse T.
Published: September 2011

Recessive resistance to lettuce mosaic virus (LMV) is conferred in lettuce by the mo1 gene, encoding the eukaryotic translation initiation factor 4E (eIF4E). The C terminus of the viral cylindrical inclusion helicase (CI-Cter), together with the VPg, is involved directly in overcoming mo1 resistance. In this study, recombinant LMV VPg and CI-Cter proteins from wild-type or resistance-breaking isolates were expressed and purified from Escherichia coli. The allelic forms of eIF4E from susceptible or resistant lettuce cultivars were produced similarly and these proteins were used in ELISA-based assays to demonstrate the in vitro binding of the various forms of LMV CI-Cter to both lettuce eIF4E and LMV VPg proteins. All combinations tested displayed significant and specific interactions, and the interaction between the C-terminal part of the LMV CI and eIF4E was confirmed in vivo in bimolecular fluorescence complementation assays. Higher interaction signals for both CI–eIF4E and CI–VPg were observed for LMV-E, indicating that the eIF4E interaction network involving CI and VPg appears to be stronger in the case of this resistance-breaking isolate. This could suggest the need for a minimal interaction threshold for infection success in resistant lettuce, but more precise measurement of the interaction parameters linking eIF4E, VPg and CI is needed in order to reinforce such a hypothesis.
Hidden superlattice in Tl2(SC6H4S) and Tl2(SeC6H4Se) solved from powder X-ray diffraction
Authors: Stone Kevin H. , Turner Dayna L. , Singh Mayank Pratap , Vaid Thomas P. , Stephens Peter W.
Published: September 2011

The crystal structures of the isostructural title compounds poly[(μ-benzene-1,4-dithiolato)dithallium], Tl2(SC6H4S), and poly[(μ-benzene-1,4-diselenolato)dithallium], Tl2(SeC6H4Se), were solved by simulated annealing from high-resolution synchrotron X-ray powder diffraction. Rietveld refinements of an initial structure with one formula unit per triclinic cell gave satisfactory agreement with the data, but led to a structure with impossibly close non-bonded contacts. A disordered model was proposed to alleviate this problem, but an alternative supercell structure leads to slightly improved agreement with the data. The isostructural superlattice structures were confirmed for both compounds through additional data collection, with substantially better counting statistics, which revealed the presence of very weak superlattice peaks not previously seen. Overall, each structure contains Tl—S or Tl—Se two-dimensional networks, connected by phenylene bridges. The sulfur (or selenium) coordination sphere around each thallium is a highly distorted square pyramid or a `see-saw' shape, depending upon how many Tl—S or Tl—Se interactions are considered to be bonds. In addition, the two compounds contain pairs of TlIions that interact through a closed-shell `thallophilic' interaction: in the sulfur compound there are two inequivalent pairs of Tl atoms with Tl—Tl distances of 3.49 and 3.58 Å, while in the selenium compound those Tl—Tl interactions are at 3.54 and 3.63 Å.
Crystallization of the chalcogenide compound Sb8Te3
Authors: Kifune Kouichi , Fujita Tomoko , Kubota Yoshiki , Yamada Noboru , Matsunaga Toshiyuki
Published: September 2011

The crystallization of a sputtered Sb8Te3 film was examined in an X-ray powder diffraction experiment. An as-sputtered, amorphous Sb8Te3 film crystallized during heating into a structure of Sb–Te homologous series modulated along the stacking direction. During heating the lattice parameters and the modulation period γ were found to change significantly and continuously; this observation suggests a continuous change in the stacking sequence. A superspace analysis revealed that with heating the modulation period γ increased to a value that seemed to be determined by the atomic composition. Once γ reached this value it remained unchanged with cooling. A three-dimensional projection of the converged four-dimensional superspace structure corresponded to the homologous Sb8Te3 structure.
Brown trout Salmo trutta express different morphometrics due to divergence in the rearing environment
Authors: Vehanen T. , Huusko A.
Published: September 2011

Variation in the body morphology of juvenile brown trout Salmo trutta was studied for both wild and hatchery‐reared individuals from the same gene pool. The thin‐plate spline (TPS) method by pointing landmarks was used to characterize juveniles from their natal environment, the River Kuusinkijoki in eastern Finland, and from wild parents raised in a hatchery environment. Differences were found in the morphometrics of juvenile S. trutta from the two different environments. Wild S. trutta are characterized by a longer head and shorter anterior part of the trunk compared to hatchery S. trutta. Stocked to their natal river with wild S. trutta, the hatchery fish became characterized with more similar morphometrics to their wild counterparts. The characteristics of the body form are explained by the differing environmental conditions in the wild and hatchery. It is concluded that a simple hatchery environment may delay the development of morphological characteristics important in a natural river environment.
CpG island methylation of microRNAs is associated with tumor size and recurrence of non‐small‐cell lung cancer
Authors: Kitano Kentaro , Watanabe Kousuke , Emoto Noriko , Kage Hidenori , Hamano Emi , Nagase Takahide , Sano Atsushi , Murakawa Tomohiro , Nakajima Jun , Goto Akiteru , Fukayama Masashi , Yatomi Yutaka , Ohishi Nobuya , Takai Daiya
Published: September 2011

We investigated whether the CpG island methylation of certain microRNAs was associated with the clinicopathological features and the prognosis of non‐small‐cell lung cancer. The methylation of mir‐152, ‐9‐3, ‐124‐1, ‐124‐2, and ‐124‐3 was analyzed in 96 non‐small‐cell lung cancer specimens using a combined bisulfite restriction analysis. The median observation period was 49.5 months. The methylation of mir‐9‐3, ‐124‐2, and ‐124‐3 was individually associated with an advanced T factor independent of age, sex, and smoking habit. Moreover, the methylation of multiple microRNA loci was associated with a poorer progression‐free survival in a univariate analysis. Our result enlightens the accumulation of aberrant DNA methylation which occurs in concordance with the tumor progression. (Cancer Sci 2011; 102: 2126–2131)
DSM criteria for tobacco use disorder and tobacco withdrawal: a critique and proposed revisions for DSM‐5*
Authors: Baker Timothy B. , Breslau Naomi , Covey Lirio , Shiffman Saul
Published: September 2011

Aims  This paper aims to identify appropriate criteria for tobacco dependence assessment, evaluate relevant research and suggest revisions that may be incorporated into DSM‐5.

Methods  Desirable conceptual and psychometric features of tobacco dependence assessments were identified, including the types of outcomes against which such assessment should be validated. DSM‐IV criteria were matched against these criteria and compared with other dependence measures.

Results  DSM‐IV criteria were found to be ambiguous, little used in tobacco research, and have relatively low predictive validity. Other dependence measures were found to have greater validity in the prediction of important dependence features such as relapse likelihood. Strength of urges to smoke on typical smoking days and during abstinence, markers of nicotine intake or frequency of smoking and latency to smoke soon after waking were found to be useful dependence measures.

Conclusion  The use and utility of DSM‐5 will be enhanced by eliminating most DSM‐IV criteria and adding new ones based on smoking pattern, smoking heaviness, and the severity of craving during periods of smoking and withdrawal.