bluuebunny/crossref_metadata_2025 huggingface dataset:
North Atlantic ventilation of “southern‐sourced” deep water in the glacial ocean
Authors: Kwon Eun Young , Hain Mathis P. , Sigman Daniel M. , Galbraith Eric D. , Sarmiento Jorge L. , Toggweiler J. R.
Published: April 2012

One potential mechanism for lowering atmospheric CO2 during glacial times is an increase in the fraction of the global ocean ventilated by the North Atlantic, which produces deep water with a low concentration of unused nutrients and thus drives the ocean's biological pump to a high efficiency. However, the data indicate that during glacial times, a water mass low in 13C/12C and 14C/C occupied the deep Atlantic, apparently at the expense of North Atlantic Deep Water (NADW). This water is commonly referred to as “southern‐sourced” because of its apparent entry into the Atlantic basin from the South, prompting the inference that it was ventilated at the Southern Ocean surface. Here, we propose that this deep Atlantic water mass actually included a large fraction of North Atlantic‐ventilated water, the chemical characteristics of which were altered by recirculation in the deep Southern and Indo‐Pacific oceans. In an ocean model sensitivity experiment that reduces Antarctic Bottom Water formation and weakens its overturning circulation, we find that a much greater fraction of NADW is transported into the Southern Ocean without contacting the surface and is entrained and mixed into the southern‐sourced deep water that spreads into the global abyssal ocean. Thus, North Atlantic ventilation takes over more of the ocean interior, lowering atmospheric CO2, and yet the abyssal Atlantic is filled from the South with old water low in 13C/12C and 14C/C, consistent with glacial data.
Ground‐based high spectral resolution observations of the entire terrestrial spectrum under extremely dry conditions
Authors: Turner D. D. , Mlawer E. J. , Bianchini G. , Cadeddu M. P. , Crewell S. , Delamere J. S. , Knuteson R. O. , Maschwitz G. , Mlynczak M. , Paine S. , Palchetti L. , Tobin D. C.
Published: April 2012

A field experiment was conducted in northern Chile at an altitude of 5.3 km to evaluate the accuracy of line‐by‐line radiative transfer models in regions of the spectrum that are typically opaque at sea level due to strong water vapor absorption. A suite of spectrally resolved radiance instruments collected simultaneous observations that, for the first time ever, spanned the entire terrestrial thermal spectrum (i.e., from 10 to 3000 cm−1, or 1000 to 3.3 μm). These radiance observations, together with collocated water vapor and temperature profiles, are used to provide an initial evaluation of the accuracy of water vapor absorption in the far‐infrared of two line‐by‐line radiative transfer models. These initial results suggest that the more recent of the two models is more accurate in the strongly absorbing water vapor pure rotation band. This result supports the validity of the Turner et al. (2012) study that demonstrated that the use of the more recent water vapor absorption model in climate simulations resulted in significant radiative and dynamical changes in the simulation relative to the older water vapor model.
Anesthesia and the Quantitative Evaluation of Neurovascular Coupling
Authors: Masamoto Kazuto , Kanno Iwao
Published: April 2012

Anesthesia has broad actions that include changing neuronal excitability, vascular reactivity, and other baseline physiologies and eventually modifies the neurovascular coupling relationship. Here, we review the effects of anesthesia on the spatial propagation, temporal dynamics, and quantitative relationship between the neural and vascular responses to cortical stimulation. Previous studies have shown that the onset latency of evoked cerebral blood flow (CBF) changes is relatively consistent across anesthesia conditions compared with variations in the time-to-peak. This finding indicates that the mechanism of vasodilation onset is less dependent on anesthesia interference, while vasodilation dynamics are subject to this interference. The quantitative coupling relationship is largely influenced by the type and dosage of anesthesia, including the actions on neural processing, vasoactive signal transmission, and vascular reactivity. The effects of anesthesia on the spatial gap between the neural and vascular response regions are not fully understood and require further attention to elucidate the mechanism of vascular control of CBF supply to the underlying focal and surrounding neural activity. The in-depth understanding of the anesthesia actions on neurovascular elements allows for better decision-making regarding the anesthetics used in specific models for neurovascular experiments and may also help elucidate the signal source issues in hemodynamic-based neuroimaging techniques.
Numerical simulations of separatrix instabilities in collisionless magnetic reconnection
Authors: Divin A. , Lapenta G. , Markidis S. , Newman D. L. , Goldman M. V.
Published: April 2012

Electron scale dynamics of magnetic reconnection separatrix jets is studied in this paper. Instabilities developing in directions both parallel and perpendicular to the magnetic field are investigated. Implicit particle-in-cell simulations with realistic electron-to-ion mass ratio are complemented by a set of small scale high resolution runs having the separatrix force balance as the initial condition. A special numerical procedure is developed to introduce the force balance into the small scale runs. Simulations show the development of streaming instabilities and consequent formation of electron holes in the parallel direction. A new electron jet instability develops in the perpendicular direction. The instability is closely related to the electron MHD Kelvin-Helmholtz mode and is destabilized by a flow, perpendicular to magnetic field at the separatrix. Tearing instability of the separatrix electron jet is modulated strongly by the electron MHD Kelvin-Helmholtz mode.
Bridge function for the dipolar fluid from simulation
Authors: Puibasset Joël , Belloni Luc
Published: April 2012

The exact bridge function of the Lennard-Jones dipolar (Stockmayer) fluid is extracted from Monte Carlo simulation data. The projections gmnl(r) onto rotational invariants of the non-spherically symmetric pair distribution function g(r, Ω) are accumulated during simulation. Making intensive use of anisotropic integral equation techniques, the molecular Ornstein-Zernike equation is then inverted in order to derive the direct correlation function cmnl(r), the cavity function ymnl(r), the negative excess potential of mean force lny|mnl(r), and the bridge function bmnl(r) projections. b(r, Ω) presents strong, non-universal anisotropies at high dipolar coupling. This simulation data analysis may serve as reference and guide for approximated bridge function theories of dipolar fluids and is a valuable step towards the case of more refined, nonlinear water-like geometries.
Spectroscopic ellipsometry of split ring resonators at infrared frequencies
Authors: Jakovljević M. M. , Isić G. , Vasić B. , Oates T. W. H. , Hinrichs K. , Bergmair I. , Hingerl K. , Gajić R.
Published: April 2012

Using spectroscopic ellipsometry, we have determined the plasmonic resonances of split-ring resonator arrays. The features in the ellipsometric spectra were explained by the analysis of calculated polarized complex reflection spectra. The calculated near-field and current distribution revealed the nature of the resonances. The positions of Rayleigh’s anomalies are calculated and marked in the spectra. We have also shown that oblique incidence enables excitation of plasmonic modes that are not possible to excite at normal incidence.
Space charge effect in ultrathin ferroelectric films
Authors: Lu Xiaoyan , Cao Wenwu , Li Hui
Published: April 2012

Space charge influence on the depolarization field becomes pronounced in nano-scale ferroelectric films in static state. We have studied theoretically the ferroelectric, dielectric, and piezoelectric properties of ultrathin ferroelectric films with the consideration of influence from space charges, surface, incomplete screening, and misfit strain. It is found that space charges accumulated near the surface of the film can modify the depolarization field, which results an enhancement of the polarization in ultrathin films and a persisting polarization even below the critical thickness. The singularities of the dielectric constant and piezoelectric coefficient were all being rounded near the critical thickness.
Laser energy tuning of carrier effective mass and thermopower in epitaxial oxide thin films
Authors: Abutaha A. I. , Sarath Kumar S. R. , Alshareef H. N.
Published: April 2012

The effect of the laser fluence on high temperature thermoelectric properties of the La doped SrTiO3 (SLTO) thin films epitaxially grown on LaAlO3 〈100〉 substrates by pulsed laser deposition is clarified. It is shown that oxygen vacancies that influence the effective mass of carriers in SLTO films can be tuned by varying the laser energy. The highest power factor of 0.433 W K−1 m−1 has been achieved at 636 K for a film deposited using the highest laser fluence of 7 J cm−2 pulse−1.
Scaling behavior of dynamic hysteresis in relaxor ferroelectric 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 ceramics
Authors: Zhang Y. C. , Lu C. J. , Yang Z. Z. , Ye W. N. , Xia L. H.
Published: April 2012

The scaling behaviors of dynamic ferroelectric hysteresis in the relaxor ferroelectric 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 (PMNT67/33) ceramics near the morphotropic phase boundary (MPB) and other PMNT systems out of MPB region were investigated. The scaling relation of hysteresis area 〈A〉 against frequency f and field amplitude E0 for minor loops takes the form of 〈A〉∝f−0.2391E04.8779; while for the saturated loops, it is 〈A〉∝f 0.0401E00.5722. The scaling relations of PMNT67/33 ceramics are significantly different from those of other ferroelectrics, and the results of the analysis indicate that domain reversal in it is much more sensitive to the change of E0 at low electric field and responses more quickly to f at high electric field than other normal ferroelectrics. The coexistence of rhombohedral (R), monoclinic (M) and tetragonal (T) phases near the MPB and the polar nanoregions seems to play the key role in the dynamic behavior of the domain reversal in relaxor PMNT67/33 ceramics.
Geometric influence on Ruderman-Kittel-Kasuya-Yosida interactions in zigzag carbon nanotubes
Authors: Bunder J. E. , Hill James M.
Published: April 2012

We derive an analytic description of the spin susceptibility in finite length zigzag carbon nanotubes (CNT) with chirality (n, 0). The spin susceptibility is proportional to the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions which describes indirect carrier mediated exchange coupling between localized magnetic moments. We show that the strongest RKKY interactions are along the edges of the nanotube and in the thermodynamic limit at half filling with spin symmetry the shape of the susceptibility curve about the edge of the CNT can be determined solely by the lattice geometry represented by the parameter n and a parameter L which describes the nanotube length. We also show that the introduction of Zeeman splitting or doping may have no effect on the spin susceptibility, provided n is small. A detailed knowledge of magnetic interactions, such as RKKY interactions, in CNT is of vital importance to the development of nanotechnology applications.
Source/drain electrodes contact effect on the stability of bottom-contact pentacene field-effect transistors
Authors: Yu Xinge , Yu Junsheng , Huang Wei , Zhang Lin , Zeng Hongjuan
Published: April 2012

Bottom-contact pentacene field-effect transistors were fabricated with a PMMA dielectric layer, and the air stability of the transistors was investigated. To characterize the device stability, the field-effect transistors were exposed to ambient conditions for 30 days and subsequently characterized. The degradation of electrical performance was traced to study the variation of field-effect mobility, saturation current and off-state current. By investigating the morphology variance of the pentacene film at the channel and source/drain (S/D) contact regions by atomic force microscopy, it was clear that the morphology of the pentacene film adhered to the S/D degenerated dramatically. Moreover, by studying the variation of contact resistance in detail, it was found that the S/D contact effect was the main reason for the degradation in performance.
Dry matter allocation in Medicago arborea and Medicago citrina in response to drought and defoliation
Authors: Lefi Elkadri , Conesa Miquel À. , Cifre Josep , Gulías Javier , Medrano Hipólito
Published: April 2012

Soil water availability is one of the main factors determining plant growth and forage production. The effects of soil water deficit on the development of two woody Mediterranean Medicago species, M. arborea and M. citrina were studied. A field experiment was carried out in the University of the Balearic Islands (Spain), under irrigated and drought conditions on both non-defoliated plants (NDP) and defoliated plants (DP). Under drought, all studied parameters for NDP were affected by water stress in summer, though there were no significant differences between species for shoot biomass (B). However, M. citrina maintained significantly higher leaf biomass than M. arborea, which represents a great part of B. On the contrary, M. arborea plants suffered total leaf senescence in summer, and B was totally composed of woody parts. For DP, spring–autumn was a favourable period for plant growth and development, under both water regimes. In well irrigated M. citrina plants, and compared with M. arborea, the capacity of regrowth was higher, and leaf area was similar for NDP and for DP. During summer, the regrowth was sensitive to the extreme temperatures. In drought conditions, the capacity of regrowth was relatively favoured in spring but completely inhibited in summer for both species.
Toll-like receptor 4-activated B cells out-compete Toll-like receptor 9-activated B cells to establish peripheral immunological tolerance
Authors: Matheu Melanie P. , Su Yan , Greenberg Milton L. , Blanc Caroline A. , Parker Ian , Scott David W. , Cahalan Michael D.
Published: April 2012

B-cell–induced peripheral T-cell tolerance is characterized by suppression of T-cell proliferation and T-cell–dependent antibody production. However, the cellular interactions that underlie tolerance induction have not been identified. Using two-photon microscopy of lymph nodes we show that tolerogenic LPS-activated membrane-bound ovalbumin (mOVA) B cells (LPS B cells) establish long-lived, highly motile conjugate pairs with responding antigen-specific OTII T cells but not with antigen-irrelevant T cells. Treatment with anti–CTLA-4 disrupts persistent B-cell–T-cell (B–T) contacts and suppresses antigen-specific tolerance. Nontolerogenic CpG-activated mOVA B cells (CpG B cells) also form prolonged, motile conjugates with responding OTII T cells when transferred separately. However, when both tolerogenic and nontolerogenic B-cell populations are present, LPS B cells suppress long-lived CpG B–OTII T-cell interactions and exhibit tolerogenic dominance. Contact of LPS B cells with previously established B–T pairs resulted in partner-swapping events in which LPS B cells preferentially migrate toward and disrupt nontolerogenic CpG mOVA B-cell–OTII T-cell pairs. Our results demonstrate that establishment of peripheral T-cell tolerance involves physical engagement of B cells with the responding T-cell population, acting in a directed and competitive manner to alter the functional outcome of B–T interactions.
What does being initiated severely into a group do? The role of rewards
Authors: Kamau Caroline
Published: April 2012

Undergoing an admission process (an initiation) can induce exaggerated feelings about a group, but there is little research about the role of rewards. This study replicated Aronson and Mills’ (1959) experiment. Seventy participants underwent either a severe initiation or a mild initiation. After the initiation, about half the sample received an extrinsic reward for merely completing the task. The remaining half did not receive an extrinsic reward. This was to vary the amount of dissonance. Initiation severity and reward condition had significant, noncrossing interactions. A reward led to higher group identity than no reward, supporting Levine and Moreland's (1994) group socialization model. A severe initiation did not lead to more group identity than a mild initiation; therefore, Aronson and Mills’ findings were not replicated. Interestingly, a mild initiation followed by a reward led to more group identity than a severe initiation followed by a reward. Another unexpected finding was that the extrinsic reward made no difference to group identity if the initiation was severe. Effects on ratings of the discussion were nonsignificant. Future research needs to establish how new group members ponder the severity of the admission process during the cost–benefit calculation preceding their identification with a group.
Site Choice among Minnesota Walleye Anglers: The Influence of Resource Conditions, Regulations and Catch Orientation on Lake Preference
Authors: Carlin Caroline , Schroeder Susan A. , Fulton David C.
Published: April 2012

Understanding angler site choice preferences is important in the management of recreational fisheries to forecast angling demand and effort. This study investigated lake choice by recreational anglers fishing for walleye Sander vitreus in Minnesota and examined how choices were influenced by lake characteristics, angler demographics, and angler catch orientation. We collected data through a stated choice preference experiment using a survey administered to a sample of Minnesota resident (n = 1096) and nonresident (n = 535) anglers. Multinomial probit choice models were used to estimate preferences in lake choice. Lake characteristics included walleye abundance, walleye size, bag limit, slot limit, and distance from primary residence. Models included (1) lake characteristics only, (2) lake characteristics and angler demographics, and (3) lake characteristics with angler demographics and catch orientation factors. The coefficients of lake attributes had expected signs with greater preference for higher walleye abundance, larger walleye, bigger bag limits, absence of slot limits, and less driving time from home (P < 0.001 for all lake characteristics in the first model). Lake choice was influenced by the interaction of lake characteristics with age (negative with abundance of fish, P < 0.100; positive with distance from home, P < 0.001), metropolitan and out-of-state residency (positive with distance from home, P < 0.001), and strength of preference for walleye (positive with distance, P < 0.01). A stronger orientation to keep walleye was positively related to increased bag limits (P < 0.001) and negatively related to slot limits (P < 0.01). Study results have clear implications for managers—bag limits, relative to other lake characteristics, had a large influence on anglers’ lake choice for walleye fishing. Because of a stronger catch orientation among walleye anglers, low bag limits reduce lake preference. The results clarify the trade-offs that anglers make when selecting a place to fish for walleye and demonstrate how different management scenarios might influence angler participation.

Received July 20, 2011; accepted January 4, 2012
On the time course of exogenous cueing effects in bilinguals: Higher proficiency in a second language is associated with more rapid endogenous disengagement
Authors: Mishra Ramesh K. , Hilchey Matthew D. , Singh Niharika , Klein Raymond M.
Published: April 2012

Previous investigations have demonstrated a bilingual advantage on various aspects of executive control. It remains unclear how the language proficiency of bilinguals might relate to the mechanisms involved in attentional disengagement. In the present investigation, we tested the hypothesis that high bilingual proficiency would lead to a more rapid endogenous disengagement of attention from task-irrelevant peripheral cues. We predicted that more rapid attentional disengagement would result in an earlier appearance of inhibition of return (IOR). In this study Hindi–English bilinguals who differed in their L2 (English) proficiency participated in a target detection task. Visual targets were preceded by uninformative peripheral cues at various stimulus onset asynchronies (SOAs) allowing for us to visualize the time course of cue-related facilitation and inhibition. High-proficient Hindi–English bilinguals showed an earlier appearance of IOR than did low-proficient bilinguals, suggesting increased efficiency in disengagement of attention from task-irrelevant inputs. Furthermore, consistent with the “global” advantage that characterizes bilinguals in many tasks, the high-proficient group outperformed low-proficient bilinguals in overall reaction time.
How does Encoding Context Affect Memory in Younger and Older Adults?
Authors: Fernandes Myra A. , Manios Michelle
Published: April 2012

How does encoding context affect memory? Participants studied visually presented words viewed concurrently with a rich (intact face) or weak (scrambled face) image as context and subsequently made “Remember”, “Know”, or “New” judgements to words presented alone. In Experiment 1a, younger, but not older, adults showed higher recollection accuracy to words from rich- than from weak-context encoding trials. The age-related deficit in recollection occurred, in Experiment 1b, even when encoding and retrieval time was doubled in older adults, suggesting that insufficient processing time cannot account for this age-related deficit. In Experiment 1c, dividing attention in young, during encoding, reduced overall memory, though the recollection boost from rich encoding contexts remained, suggesting that reduced attention resources cannot explain this age-related deficit. Experiment 2 showed that an own-age bias, to face images as context, could not explain the age-related differences either. Results suggest that age deficits in recollection stem from a lack of spontaneous binding, or elaboration, of context to target information during encoding.
Emotional Nouns Affect Attachment Decisions in Sentence Completion Tasks
Authors: Fraga Isabel , Piñeiro Ana , Acuña-Fariña Carlos , Redondo Jaime , García-Orza Javier
Published: April 2012

We report three sentence completion experiments in which we manipulate the emotional dimension of the nouns in a complex noun phrase (NP) that precedes a relative clause (RC), as in the classic ambiguity in Someone shot the servant of the actress who was on the balcony. The aim was to see whether nouns such as orgy or genocide affect the well-established preference of Spanish to adjoin the relative clause high in the tree (to servant instead of actress in the example above). We manipulated the valence and arousal of the lexical entities residing in the NP. Our results indicate that (a) the inclusion of either pleasant or unpleasant words induces changes in the usual NP1 preference found in Spanish; (b) the effects of high-arousal words are especially clear, in that they pull RC adjunction towards the NP where they are located, be it the NP1 or the NP2; and (c) in the context of sentence production, these kinds of words seem intense enough to promote changes in (and even reverse) a solid syntactic bias. We discuss these findings in the light of existing theories of syntactic ambiguity resolution.
Up north and down south: Implicit associations between topography and cardinal direction
Authors: Brunyé Tad T. , Gagnon Stephanie A. , Waller David , Hodgson Eric , Tower-Richardi Sarah , Taylor Holly A.
Published: April 2012

Route planners show a reliable tendency to select south- relative to north-going routes between two horizontally (east/west) aligned landmarks, suggesting the application of a north-is-up heuristic (Brunyé, Mahoney, Gardony, & Taylor, 2010). The source of this north-is-up bias remains unknown, and there is no strong evidence to suggest that it is due to explicit strategy use. In four experiments, we attempt to further elucidate the source of this effect by testing whether it can be attributed to implicit associations between cardinal direction (north/south) and topography (mountainous/level terrain). Experiments 1 and 2 used an adapted Implicit Association Test and demonstrate automatically activated judgements that associate north with mountainous and south with relatively level terrain. Experiment 3 rules out the possibility that this effect is due to the local topography of New England by replicating in participants from the topographically dissimilar Midwestern United States. Finally, Experiment 4 tests the relative contribution of implicit versus explicit associations between cardinal direction and topography in predicting route-planning asymmetries; we show that implicit associations are a stronger predictor of southern route biases than explicit processes. Overall, results demonstrate that the conceptualization of space can be driven by physically unfounded implicit associations between cardinal directions and topographical features, and these associations are at least partially responsible for southern route preferences.
Eye gaze cannot be ignored (but neither can arrows)
Authors: Galfano Giovanni , Dalmaso Mario , Marzoli Daniele , Pavan Giulia , Coricelli Carol , Castelli Luigi
Published: April 2012

Recent studies have tried to shed light on the automaticity of attentional shifts triggered by gaze and arrows with mixed results. In the present research, we aimed at testing a strong definition of resistance to suppression for orienting of attention elicited by these two cues. In five experiments, participants were informed with 100% certainty about the future location of a target they had to react to by presentation of either a direction word at the beginning of each trial or instructions at the beginning of each block. Gaze and arrows were presented before the target as uninformative distractors irrelevant for the task. The results showed similar patterns for gaze and arrows—namely, an interference effect when the distractors were incongruent with the upcoming target location. This suggests that the orienting of attention mediated by gaze and arrows can be considered as strongly automatic.
Interpreting Conjoined noun Phrases and Conjoined Clauses: Collective versus Distributive Preferences
Authors: Clifton Charles , Frazier Lyn
Published: April 2012

Two experiments are reported that show that introducing event participants in a conjoined noun phrase (NP) favours a single event (collective) interpretation, while introducing them in separate clauses favours a separate events (distributive) interpretation. In Experiment 1, acceptability judgements were speeded when the bias of a predicate toward separate events versus a single event matched the presumed bias of how the subjects' referents were introduced (as conjoined noun phrases or in conjoined clauses). In Experiment 2, reading of a phrase containing an anaphor following conjoined noun phrases was facilitated when the anaphor was they, relative to when it was neither/each of them; the opposite pattern was found when the anaphor followed conjoined clauses. We argue that comprehension was facilitated when the form of an anaphor was appropriate for how its antecedents were introduced. These results address the very general problem of how we individuate entities and events when presented with a complex situation and show that different linguistic forms can guide how we construe a situation. The results also indicate that there is no general penalty for introducing the entities or events separately—in distinct clauses as “split” antecedents.
Cross-Domain Interference Costs during Concurrent Verbal and Spatial Serial Memory Tasks are Asymmetric
Authors: Morey Candice C. , Mall Jonathan T.
Published: April 2012

Some evidence suggests that memory for serial order is domain-general. Evidence also points to asymmetries in interference between verbal and visual–spatial tasks. We confirm that concurrently remembering verbal and spatial serial lists provokes substantial interference compared with remembering a single list, but we further investigate the impact of this interference throughout the serial position curve, where asymmetries are indeed apparent. A concurrent verbal order memory task affects spatial memory performance throughout the serial positions of the list, but performing a spatial order task affects memory for the verbal serial list only for early list items; in the verbal task only, the final items are unaffected by a concurrent task. Adding suffixes eliminates this asymmetry, resulting in impairment throughout the list for both tasks. These results suggest that domain-general working memory resources may be supplemented with resources specific to the verbal domain, but perhaps not with equivalent spatial resources.
Asynchrony in discrete bimanual aiming: Evidence for visual strategies of coordination
Authors: Miller Kirsty A. , Smyth Mary M.
Published: April 2012

The bimanual coupling literature supposes an inherent drive for synchrony between the upper limbs when making discrete bimanual movements. The level of synchrony is argued to be task dependent, reliant on the visual demands of the two targets, and the result of a complex pattern of hand and eye movements (Bingham, Hughes, & Mon-Williams, 2008; Riek, Tresilian, Mon-Williams, Coppard, & Carson, 2003). However, recent work by Bruyn and Mason (2009) suggests that temporal coordination is not solely influenced by visual saccades. In this experimental series, a total of 8 participants performed congruent movements to targets either near or far from the midline. Targets far from the midline, requiring a visual saccade, resulted in greater terminal asynchrony. Initial and terminal asynchrony were not consistent, but linked to the task demands at that stage of the movement. If the asynchrony evident at the end of a bimanual movement is due to a complex pattern of hand and eye movements then the removal of visual feedback should result in an increase in synchrony. Sixteen participants then completed congruent and incongruent bimanual aiming movements to near and/or far targets. Movements were made with or without visual feedback of hands and targets. Analyses revealed that movements made without visual feedback showed increased synchrony between the limbs, yet movements to incongruent targets still showed greater asynchrony. We suggest that visual constraints are not the sole cause of asynchrony in discrete bimanual movements.
Phonological, visual, and semantic coding strategies and children's short-term picture memory span
Authors: Henry Lucy A. , Messer David , Luger-Klein Scarlett , Crane Laura
Published: April 2012

Three experiments addressed controversies in the previous literature on the development of phonological and other forms of short-term memory coding in children, using assessments of picture memory span that ruled out potentially confounding effects of verbal input and output. Picture materials were varied in terms of phonological similarity, visual similarity, semantic similarity, and word length. Older children (6/8-year-olds), but not younger children (4/5-year-olds), demonstrated robust and consistent phonological similarity and word length effects, indicating that they were using phonological coding strategies. This confirmed findings initially reported by Conrad (1971), but subsequently questioned by other authors. However, in contrast to some previous research, little evidence was found for a distinct visual coding stage at 4 years, casting doubt on assumptions that this is a developmental stage that consistently precedes phonological coding. There was some evidence for a dual visual and phonological coding stage prior to exclusive use of phonological coding at around 5–6 years. Evidence for semantic similarity effects was limited, suggesting that semantic coding is not a key method by which young children recall lists of pictures.
Meta‐analysis of randomized controlled trials evaluating left ventricular vs. biventricular pacing in heart failure: effect on all‐cause mortality and hospitalizations
Authors: Boriani Giuseppe , Gardini Beatrice , Diemberger Igor , Reggiani Maria Letizia Bacchi , Biffi Mauro , Martignani Cristian , Ziacchi Matteo , Valzania Cinzia , Gasparini Maurizio , Padeletti Luigi , Branzi Angelo
Published: April 2012

Aim

Randomized controlled trials (RCTs) showed that biventricular (BiV) pacing reduces heart failure (HF) hospitalizations and mortality in patients with New York Heart Association (NYHA) class III–IV HF, left ventricular (LV) dysfunction, and wide QRS. We performed a systematic review and meta‐analysis of the RCTs comparing LV‐only vs. biventricular (BiV) pacing in candidates for cardiac resynchronization therapy (CRT).

Methods and results

The systematic review selected five RCTs (out of 1888 analysed reports) with a cumulative number of 372 patients randomized to BiV pacing and 258 to LV‐only pacing. The meta‐analysis shows that BiV pacing is not superior to LV‐only pacing and that these two pacing modalities do not differ with regard to death or heart transplantation [LV‐only vs. BiV pacing odds ratio (OR) 1.24, 95% confidence interval (CI) 0.57–2.70 with the fixed effect model, OR 1.25, 95% CI 0.48–3.24 with the random effect model]. Specific data on hospitalizations were available only in two RCTs with a cumulative number of 127 patients randomized to BiV and 123 to LV‐only pacing. The meta‐analysis shows that BiV pacing is not superior to LV‐only pacing and that these two pacing modalities do not differ with regard to this outcome (LV‐only vs. BiV pacing OR 0.86, 95% CI 0.49–1.50 with the fixed effect model, OR 0.86, 95% CI 0.49–1.50 with the random effect model).

Conclusions

Biventricular pacing is not superior to LV‐only pacing, and these two pacing modalities appear to achieve similar efficacy in candidates for CRT for moderate to severe HF, in terms of all‐cause mortality and hospitalizations during follow‐up.
Double jeopardy: the influence of excessive daytime sleepiness and impaired cognition on health‐related quality of life in adults with heart failure
Authors: Riegel Barbara , Ratcliffe Sarah J. , Weintraub William S. , Sayers Steven L. , Goldberg Lee R. , Potashnik Sheryl , Weaver Terri E. , Pressler Susan J.
Published: April 2012

Aims

To determine how excessive daytime sleepiness (EDS) and impaired cognition contribute to health‐related quality of life (HRQL) in heart failure (HF).

Methods and results

Adults with chronic HF were enrolled into a prospective cohort study. Data were obtained from 280 subjects enrolled from three sites in the northeastern USA; 242 completed the 6‐month study. At baseline, cohorts with and without EDS were identified using the Epworth Sleepiness Scale. Each EDS group was further subdivided into those with and without impaired cognition using a battery of five neuropsychological tests. Two disease‐specific measures, the Kansas City Cardiomyopathy Questionnaire (KCCQ) and the Functional Outcomes of Sleep Questionnaire (FOSQ), were used to measure HRQL. General linear modelling of square‐transformed variables was used to test the hypothesis that cohort membership was a significant predictor of HRQL. At 6 months the remaining sample was 62.5 [standard deviation (SD) 12] years old, mostly male (63%), white (65%), and functionally compromised [72% New York Heart Association (NYHA) class III/IV]. The cohort with both EDS and impaired cognition had the lowest KCCQ overall summary score (60.5 ± 22.5) compared with the cohort without EDS or impaired cognition (74.6 ± 17.4, P ≤ 0.001). A similar effect was seen on the FOSQ (16.0 ± 2.8 vs. 18.5 ± 2.2, P < 0.001).

Conclusion

Impaired cognition alone did not explain poor HRQL, but the addition of EDS poses a significant risk for poor HRQL. Interventions designed to influence EDS may improve HRQL in this population.
The Role of Application Assistance and Information in College Decisions: Results from the H&R Block Fafsa Experiment*
Authors: Bettinger Eric P. , Long Bridget Terry , Oreopoulos Philip , Sanbonmatsu Lisa
Published: April 2012

Growing concerns about low awareness and take-up rates for government support programs like college financial aid have spurred calls to simplify the application process and enhance visibility. We present results from a randomized field experiment in which low-income individuals receiving tax preparation help were also offered immediate assistance and a streamlined process to complete the Free Application for Federal Student Aid (FAFSA) for themselves or their children. Treated participants were also provided with aid estimates that were compared against tuition cost amounts for nearby colleges. The combined assistance and information treatment substantially increased FAFSA submissions and ultimately the likelihood of college attendance, persistence, and aid receipt. In particular, high school seniors whose parents received the treatment were 8 percentage points more likely to have completed two years of college, going from 28% to 36%, during the first three years following the experiment. Families who received aid information but no assistance with the FAFSA did not experience improved outcomes. The findings suggest many other opportunities for using personal assistance to increase participation in programs that require filling out forms to become eligible.
A Critical Assessment of the Quantification of Wheat Grain Arabinoxylans Using a Phloroglucinol Colorimetric Assay
Authors: Kiszonas Alecia M. , Courtin Christophe M. , Morris Craig F.
Published: April 2012

Arabinoxylans (AX) of wheat (Triticum aestivum L.) play a critical role in processing, end‐use quality, and human health and nutrition. Consequently, an efficient, accurate method of AX quantification is desirable. The objective of this work was to evaluate a standard phloroglucinol colorimetric method for quantification of wheat AX. The method is based on the formation and spectrophotometric quantification of a phloroglucide product that results from the reaction of furfural produced during the condensation of pentose sugars with phloroglucinol. Method parameters, including reaction reagents and reaction times, were varied to identify areas for improved accuracy and consistency. Phloroglucide formation at three xylose concentrations was examined over time. The optimal reaction reagents and reaction times were determined based upon improved consistency in xylose quantification. The optimized method was used on xylose and arabinose standards and on whole meal wheat samples for total and water‐extractable AX content. Glucose was shown to be unnecessary in the reaction and was eliminated. A second‐order polynomial equation provided a slightly better fit to the nearly linear standard xylose curve. A reduced concentration of phloroglucinol of 10% was found to give equivalent results to the standard 20%. Optimum reaction time was 25 min, and it required the inclusion of all reagents. The phloroglucide product decreased in absorbance over time such that, within the range of xylose concentration examined, about 40–50% of the colored product was lost over 100 min; however, the rate of loss was linear over time. Four operators performed the optimized method on whole wheat meal samples for total and water‐extractable AX. Inter‐ and intraoperator variation was identified as an area requiring further study and improvement. However, all operators tended to rank the samples in a consistent manner. Compared with a gas chromatography–flame ionization detection method, the phloroglucinol method underestimated total AX by about 2.3% and water‐extractable AX by about 0.08%.
Differences in Frequency of Transposable Elements Presence in Botrytis cinerea Populations from Several Hosts in Greece
Authors: Samuel Stylianos , Veloukas Thomas , Papavasileiou Antonios , Karaoglanidis George S.
Published: April 2012

This study was conducted primarily to investigate the presence and frequency distribution of the transposable elements Boty and Flipper in populations of the necrotroph plant pathogen Botrytis cinerea in Greece. In total, 334 isolates were collected from diseased grape, strawberry, tomato, cucumber, kiwifruit, and apple fruit during 2009. The presence of the two transposable elements was based on polymerase chain reaction detection. Results showed that all the sampled hosts occurred in sympatry, with four possible different genotypes (transposa type carrying both transposable elements, Boty type carrying only the Boty element, Flipper type carrying only the Flipper element, and vacuma type carrying neither transposable element). Marked differences in genotype frequencies among populations were observed. In tomato, cucumber, grape, and strawberry, transposa isolates carrying both elements were predominant in the populations whereas, in kiwifruit and apple fruit populations, the vacuma isolates were prevailing. Furthermore, in kiwi and apple fruit populations, high frequencies of Flipper-type isolates were observed. In an attempt to explain the observed predominance of vacuma isolates in kiwifruit populations, the mycelial growth rate of a set of vacuma isolates was compared with the mycelial growth rate of a set of transposa isolates at three different temperatures (0, 10, and 20°C). The same set of isolates was used to compare pathogenicity of isolates on wound-inoculated kiwifruit incubated at two different temperatures (0 and 20°C), in terms of disease incidence and disease severity. In addition, the selected isolates were used to compare their ability in causing latent infections on kiwifruit in the field. The results showed that vacuma and transposa isolates had similar mycelial growth rates at the limiting temperatures of 0 and 10°C, while vacuma isolates grew faster at the optimum temperature of 20°C. Similarly, there was no significant difference regarding pathogenicity on kiwifruit between transposa and vacuma isolates. However, artificial inoculations conducted on blossoms in the field showed that vacuma isolates caused significantly higher incidence of latent infections.
Molecular Characterization of Fusarium Head Blight Pathogens Sampled from a Naturally Infected Disease Nursery Used for Wheat Breeding Programs in China
Authors: Puri K. D. , Saucedo E. S. , Zhong S.
Published: April 2012

Fusarium head blight (FHB) is an important disease of wheat and barley worldwide. The disease is primarily caused by members of the Fusarium graminearum species complex, consisting of at least 14 phylogenetically distinct species. To determine the population structure of the FHB pathogens in a naturally infected disease nursery located at Jianyang, Fujian province, China, 160 isolates of the F. graminearum complex were recovered from symptomatic wheat spike samples collected in two consecutive years (2008 and 2009) and characterized using species- and chemotype-specific polymerase chain reaction as well as variable number tandem repeat (VNTR) markers. All isolates analyzed were identified as F. asiaticum except for one isolate, which was identified as F. avenaceum. Among the 159 F. asiaticum isolates, 126 (79%) isolates were of the nivalenol (NIV) type while 29 (18%) isolates were of the 15-acetyl deoxynivalenol type and only 4 (3%) isolates were of the 3-acetyl deoxynivalenol type. The 10 VNTR markers revealed 124 distinct haplotypes and 76 polymorphic alleles across the whole population. The two subpopulations (FA-08 and FA-09) grouped based on the year of collection exhibited low genetic differentiation (Fst = 0.032) and high gene flow (Nm = 15.13). However, a significant genetic differentiation was found within the NIV-type isolates as revealed by the Structure software. The pairwise linkage disequilibrium tests did not support the hypothesis of random mating in the population because half (48.8%) of the locus pairs showed a linkage disequilibrium (P > 0.05). Our results suggest that FHB in this nursery was caused by a genetically homogenous and non-random mating population of F. asiaticum in 2008 and 2009, which consisted of all three trichothecene types with various levels of aggressiveness.
Niche-based mechanisms operating within extreme habitats: a case study of subterranean amphipod communities
Authors: Fišer Cene , Blejec Andrej , Trontelj Peter
Published: April 2012

It has been suggested that both niche-based and neutral mechanisms are important for biological communities to evolve and persist. For communities in extreme and isolated environments such as caves, theoretical and empirical considerations (low species turnover, high stress, strong convergence owing to strong directional selection) predict neutral mechanisms and functional equivalence of species. We tested this prediction using subterranean amphipod communities from caves and interstitial groundwater. Contrary to expectations, functional morphological diversity within communities in both habitats turned out to be significantly higher than the null model of randomly assembled communities. This suggests that even the most extreme, energy-poor environments still maintain the potential for diversification via differentiation of niches.
Working against gravity: horizontal honeybee waggle runs have greater angular scatter than vertical waggle runs
Authors: Couvillon Margaret J. , Phillipps Hunter L. F. , Schürch Roger , Ratnieks Francis L. W.
Published: April 2012

The presence of noise in a communication system may be adaptive or may reflect unavoidable constraints. One communication system where these alternatives are debated is the honeybee (
Apis mellifera
) waggle dance. Successful foragers communicate resource locations to nest-mates by a dance comprising repeated units (waggle runs), which repetitively transmit the same distance and direction vector from the nest. Intra-dance waggle run variation occurs and has been hypothesized as a colony-level adaptation to direct recruits over an area rather than a single location. Alternatively, variation may simply be due to constraints on bees' abilities to orient waggle runs. Here, we ask whether the angle at which the bee dances on vertical comb influences waggle run variation. In particular, we determine whether horizontal dances, where gravity is not aligned with the waggle run orientation, are more variable in their directional component. We analysed 198 dances from foragers visiting natural resources and found support for our prediction. More horizontal dances have greater angular variation than dances performed close to vertical. However, there is no effect of waggle run angle on variation in the duration of waggle runs, which communicates distance. Our results weaken the hypothesis that variation is adaptive and provide novel support for the constraint hypothesis.
Ontogenetic niche shifts in dinosaurs influenced size, diversity and extinction in terrestrial vertebrates
Authors: Codron Daryl , Carbone Chris , Müller Dennis W. H. , Clauss Marcus
Published: April 2012

Given the physiological limits to egg size, large-bodied non-avian dinosaurs experienced some of the most extreme shifts in size during postnatal ontogeny found in terrestrial vertebrate systems. In contrast, mammals—the other dominant vertebrate group since the Mesozoic—have less complex ontogenies. Here, we develop a model that quantifies the impact of size-specific interspecies competition on abundances of differently sized dinosaurs and mammals, taking into account the extended niche breadth realized during ontogeny among large oviparous species. Our model predicts low diversity at intermediate size classes (between approx. 1 and 1000 kg), consistent with observed diversity distributions of dinosaurs, and of Mesozoic land vertebrates in general. It also provides a mechanism—based on an understanding of different ecological and evolutionary constraints across vertebrate groups—that explains how mammals and birds, but not dinosaurs, were able to persist beyond the Cretaceous–Tertiary (K–T) boundary, and how post-K–T mammals were able to diversify into larger size categories.