bluuebunny/crossref_metadata_2025 huggingface dataset:
Counter-regulation in affective attentional biases: Evidence in the additional singleton paradigm
Authors: Wentura Dirk , Müller Philipp , Rothermund Klaus , Voss Andreas
Published: April 2017

We investigated motivational influences on affective processing biases; specifically, we were interested in whether anticipating positive versus negative future outcomes during goal pursuit affects attentional biases toward positive or negative stimuli. Attentional valence biases were assessed with the additional singleton task, with the task-irrelevant singleton colors being positive, negative or neutral. The motivational relevance of colors was established in a preceding task: In a balanced design, one color acquired positive valence by indicating the chance to win money, and a different color acquired negative valence by indicating the danger to lose money. Blocks of the additional singleton task were associated with either the chance of winning money (positive outcome focus) or the danger of losing money (negative outcome focus). We found an interaction of outcome focus and singleton valence in the accuracy rates, indicating an incongruency effect: Attentional capture was stronger for positive (negative) singletons in the negative (positive) outcome focus conditions. This result further corroborates the counter-regulation hypothesis, extending previous findings on the motivational top-down regulation of affective processing to the domain of early attentional processes.
Fast polynomial transforms based on Toeplitz and Hankel matrices
Authors: Townsend Alex , Webb Marcus , Olver Sheehan
Published: April 2017

Many standard conversion matrices between coefficients in classical orthogonal polynomial expansions can be decomposed using diagonally-scaled Hadamard products involving Toeplitz and Hankel matrices. This allows us to derive algorithms with an observed complexity ofO(Nlog2N)\mathcal {O}(N\log ^2 \! N), based on the fast Fourier transform, for converting coefficients of a degreeNNpolynomial in one polynomial basis to coefficients in another. Numerical results show that this approach is competitive with state-of-the-art techniques, requires no precomputational cost, can be implemented in a handful of lines of code, and is easily adapted to extended precision arithmetic.
Quadratic modules, 𝐶*-algebras, and free convexity
Authors: Alekseev Vadim , Netzer Tim , Thom Andreas
Published: April 2017

Given a quadratic module, we construct its universal

C
∗

C^*

-algebra, and then use methods and notions from the theory of

C
∗

C^*

-algebras to study the quadratic module. We define residually finite-dimensional quadratic modules, and characterize them in various ways, in particular via a Positivstellensatz. We give unified proofs for several existing strong Positivstellensätze, and prove some new ones. Our approach also leads naturally to interesting new examples in free convexity. We show that the usual notion of a free convex hull is not able to detect residual finite-dimensionality. We thus study a notion of free convexity which is coordinate-free. We characterize semialgebraicity of free convex hulls of semialgebraic sets, and show that they are not always semialgebraic, even at scalar level. This also shows that the membership problem for quadratic modules (a well-studied problem in Real Algebraic Geometry) has a negative answer in the non-commutative setup.
Social-Recognition versus Financial Incentives? Exploring the Effects of Creativity-Contingent External Rewards on Creative Performance
Authors: Mehta Ravi , Dahl Darren W. , Zhu Rui (Juliet)
Published: April 2017

The present work examines the role of creativity-contingent monetary versus social-recognition rewards on creative performance and provides new insights into the underlying motivational processes through which these rewards affect consumer creativity. A series of five studies demonstrate that within the context of creativity contingency, monetary rewards induce a performance focus, while social-recognition rewards induce a normative focus. Such performance (normative) focus in turn enhances (attenuates) approach motivation to be original and hence leads to higher (lower) originality in a creative task. Thus, this work not only advances the current understanding of how and why two types of widely used creativity-contingent external rewards may have contrasting effects on creative performance, but it also offers important practical insights to managers who utilize reward systems in cultivating consumer creativity in their innovation platforms.
Cerebral Revascularization for Aneurysms in the Flow-Diverter Era
Authors: Straus David C. , Brito da Silva Harley , McGrath Lynn , Levitt Michael R. , Kim Louis J. , Ghodke Basavaraj V. , Barber Jason K. , Sekhar Laligam N.
Published: April 2017

BACKGROUND: Cerebral bypass has been an important tool in the treatment of complex intracranial aneurysms. The recent advent of flow-diverting stents (FDS) has expanded the capacity for endovascular arterial reconstruction.

OBJECTIVE: We investigated how the advent of FDS has impacted the application and outcomes of cerebral bypass in the treatment of intracranial aneurysms.

METHODS: We reviewed a consecutive series of cerebral bypasses during aneurysm surgery over the course of 10 years. FDS were in active use during the last 5 years of this series. We compared the clinical characteristics, surgical technique, and outcomes of patients who required cerebral bypass for aneurysm treatment during the preflow diversion era (PreFD) with those of the postflow diversion era (PostFD).

RESULTS: We treated 1061 aneurysms in the PreFD era (from July 2005 through June 2010) and 1348 in the PostFD era (from July 2010 through June 2015). Eighty-five PreFD patients (8%) and 45 PostFD patients (3%) were treated with cerebral bypass. PreFD patients had better baseline functional status compared to PostFD patients with average preoperative modified Rankin Scale score of 0.55 in PreFD and 1.18 in PostFD.

CONCLUSION: After the introduction of FDS, cerebral bypass was performed in a lower proportion of patients with aneurysms. Patients selected for bypass in the flow-diverter era had worse preoperative modified Rankin Scale scores indicating a greater complexity of the patients. Cerebral bypass in well-selected patients and revascularization remains an important technique in vascular neurosurgery. It is also useful as a rescue technique after failed FDS treatment of aneurysms.
Results of the ANSWER Trial Using the PulseRider for the Treatment of Broad-Necked, Bifurcation Aneurysms
Authors: Spiotta Alejandro M. , Derdeyn Colin P. , Tateshima Satoshi , Mocco Jay , Crowley R. Webster , Liu Kenneth C. , Jensen Lee , Ebersole Koji , Reeves Alan , Lopes Demetrius K. , Hanel Ricardo A. , Sauvageau Eric , Duckwiler Gary , Siddiqui Adnan , Levy Elad , Puri Ajit , Pride Lee , Novakovic Roberta , Chaudry M. Imran , Turner Raymond D. , Turk Aquilla S.
Published: April 2017

BACKGROUND: The safety and probable benefit of the PulseRider (Pulsar Vascular, Los Gatos, California) for the treatment of broad-necked, bifurcation aneurysms was studied in the context of the prospective, nonrandomized, single arm clinical trial—the Adjunctive Neurovascular Support of Wide-neck aneurysm Embolization and Reconstruction (ANSWER) Trial.

OBJECTIVE: To present the results of the United States cases employing the PulseRider device as part of the ANSWER clinical trial.

METHODS: Aneurysms treated with the PulseRider device among sites enrolling in the ANSWER trial were prospectively studied and the results are summarized. Aneurysms arising at either the carotid terminus or basilar apex that were relatively broad necked were considered candidates for inclusion into the ANSWER study.

RESULTS: Thirty-four patients were enrolled (29 female and 5 male) with a mean age of 60.9 years (27 basilar apex and 7 carotid terminus). Mean aneurysm height ranged from 2.4 to 15.9 mm with a mean neck size of 5.2 mm (range 2.3-11.6 mm). In all patients, the device was delivered and deployed. Immediate Raymond I or II occlusion was achieved in 82.4% and progressed to 87.9% at 6-month follow-up. A modified Rankin Score of 2 or less was seen in 94% of patients at 6 months.

CONCLUSION: The results from the ANSWER trial demonstrate that the PulseRider device is safe and offers probable benefit as for the treatment of bifurcation aneurysms arising at the basilar apex or carotid terminus. As such, it represents a useful addition to the armamentarium of the neuroendovascular specialist.
Recent advances in visible-light-driven organic reactions
Authors: Liu Qiang , Wu Li-Zhu
Published: April 2017

In recent years, visible-light-driven organic reactions have been experiencing a significant renaissance in response to topical interest in environmentally friendly green chemical synthesis. The transformations using inexpensive, readily available visible-light sources have come to the forefront in organic chemistry as a powerful strategy for the activation of small molecules. In this review, we focus on recent advances in the development of visible-light-driven organic reactions, including aerobic oxidation, hydrogen-evolution reactions, energy-transfer reactions and asymmetric reactions. These key research topics represent a promising strategy towards the development of practical, scalable industrial processes with great environmental benefits.
Big Learning with Bayesian methods
Authors: Zhu Jun , Chen Jianfei , Hu Wenbo , Zhang Bo
Published: April 2017

The explosive growth in data volume and the availability of cheap computing resources have sparked increasing interest in Big learning, an emerging subfield that studies scalable machine learning algorithms, systems and applications with Big Data. Bayesian methods represent one important class of statistical methods for machine learning, with substantial recent developments on adaptive, flexible and scalable Bayesian learning. This article provides a survey of the recent advances in Big learning with Bayesian methods, termed Big Bayesian Learning, including non-parametric Bayesian methods for adaptively inferring model complexity, regularized Bayesian inference for improving the flexibility via posterior regularization, and scalable algorithms and systems based on stochastic subsampling and distributed computing for dealing with large-scale applications. We also provide various new perspectives on the large-scale Bayesian modeling and inference.
T-Connector Modification for Reducing Recurrent Distal Shunt Failure: Report of 2 Cases
Authors: Carnevale Joseph A , Ahmedli Nigar , Morrison John F , Asaad Wael F , Klinge Petra , Telfeian Albert
Published: April 2017

BACKGROUND AND IMPORTANCE

Cerebrospinal fluid shunt placement is used to treat the various causes of hydrocephalus by redirecting the cerebrospinal fluid to the body, most commonly from the ventricle to the peritoneum. Distal catheter displacement from the peritoneal cavity can occur as a complication, necessitating reoperation.

CLINICAL PRESENTATION

We report 2 such cases in obese patients involving retropulsion of the distal tubing. To address this complication, we implanted a T-connector to the distal catheter construct.

CONCLUSION

This study supports the use of a T-connector catheter construct to decrease and prevent the possibility of distal peritoneal catheter retropulsion in cases of elevated intra-abdominal pressure, both prophylactically and in revisions.
Suzaku Wide-band All-sky Monitor (WAM) observations of GRBs and SGRs
Authors: Yamaoka Kazutaka , Ohno Masanori , Tashiro Makoto S. , Hurley Kevin , Krimm Hans A. , Lien Amy Y. , Ohmori Norisuke , Sugita Satoshi , Urata Yuji , Yasuda Tetsuya , Enomoto Junichi , Fujinuma Takeshi , Fukazawa Yasushi , Hanabata Yoshitaka , Iwakiri Wataru , Kawano Takafumi , Kinoshita Ryuuji , Kokubun Motohide , Makishima Kazuo , Matsuoka Shunsuke , Nagayoshi Tsutomu , Nakagawa Yujin , Nakaya Souhei , Nakazawa Kazuhiro , Nishioka Yusuke , Sakamoto Takanori , Takahashi Tadayuki , Takeda Sawako , Terada Yukikatsu , Yabe Seiya , Yamauchi Makoto , Yoshida Hiraku
Published: April 2017

We will review results for gamma-ray bursts (GRBs) and soft gamma repeaters (SGRs), obtained from the Suzaku Wide-band All-sky Monitor (WAM) which operated for about 10 years from 2005 to 2015. The WAM is a BGO (bismuth germanate: Bi4Ge3O12) lateral shield for the Hard X-ray Detector (HXD), used mainly for rejecting its detector background, but it also works as an all-sky monitor for soft gamma-ray transients in the 50–5000 keV range thanks to its large effective area (∼600 cm2 at 1 MeV for one detector) and wide field of view (about half of the entire sky). The WAM actually detected more than 1400 GRBs and 300 bursts from SGRs, and this detection number is comparable to that of other GRB-specific instruments. Based on the 10 years of operation, we describe timing and spectral performance for short GRBs, weak GRBs with high redshifts, and time-resolved pulses with good statistics.
Importing and Firm Productivity in Ethiopian Manufacturing
Authors: Abreha Kaleb Girma
Published: April 2017

This paper investigates the causal relationship between importing and firm productivity. Using a rich dataset from Ethiopian manufacturing over the period 1996–2011, I find that most firms rely on production inputs from the world market. These firms are better performing as shown by significant, economically large import premia. I also find strong evidence of self-selection of more productive firms into importing which is indicative of sizable import market entry costs. To examine the causal effect of importing on firm productivity, I use a model in which the static and dynamic effects of importing are separately estimated. The estimation results provide support to learning-by-importing. However, the productivity gains are small in size compared to similar findings in other studies. I provide some evidence in support of firms’ limited absorptive capacity in explaining the small productivity gains.
Toward an Optimal Pedagogy for Teamwork
Authors: Earnest Mark A. , Williams Jason , Aagaard Eva M.
Published: April 2017

Teamwork and collaboration are increasingly listed as core competencies for undergraduate health professions education. Despite the clear mandate for teamwork training, the optimal method for providing that training is much less certain. In this Perspective, the authors propose a three-level classification of pedagogical approaches to teamwork training based on the presence of two key learning factors: interdependent work and explicit training in teamwork. In this classification framework, level 1—minimal team learning—is where learners work in small groups but neither of the key learning factors is present. Level 2—implicit team learning—engages learners in interdependent learning activities but does not include an explicit focus on teamwork. Level 3—explicit team learning—creates environments where teams work interdependently toward common goals and are given explicit instruction and practice in teamwork. The authors provide examples that demonstrate each level. They then propose that the third level of team learning, explicit team learning, represents a best practice approach in teaching teamwork, highlighting their experience with an explicit team learning course at the University of Colorado Anschutz Medical Campus. Finally, they discuss several challenges to implementing explicit team-learning-based curricula: the lack of a common teamwork model on which to anchor such a curriculum; the question of whether the knowledge, skills, and attitudes acquired during training would be transferable to the authentic clinical environment; and effectively evaluating the impact of explicit team learning.
Happy Despite Pain
Authors: Peters Madelon L. , Smeets Elke , Feijge Marion , van Breukelen Gerard , Andersson Gerhard , Buhrman Monica , Linton Steven J.
Published: April 2017

Objectives:

There is preliminary evidence for the efficacy of positive psychology interventions for pain management. The current study examined the effects of an internet-based positive psychology self-help program for patients with chronic musculoskeletal pain and compared it with an internet-based cognitive-behavioral program.

Materials and Methods:

A randomized controlled trial was carried out with 3 conditions: an internet-delivered positive psychology program, an internet-delivered cognitive-behavioral program and waitlist control. A total of 276 patients were randomized to 1 of the 3 conditions and posttreatment data were obtained from 206 patients. Primary outcomes were happiness, depression, and physical impairments at posttreatment and at 6-month follow-up. Intention-to-treat analyses were carried out using mixed regression analyses.

Results:

Both treatments led to significant increases in happiness and decreases in depression. Physical impairments did not significantly decrease compared with waitlist. Improvements in happiness and depression were maintained until 6-month follow-up. There were no overall differences in the efficacy of the 2 active interventions but effects seemed to be moderated by education. Patients with a higher level of education profited slightly more from the positive psychology intervention than from the cognitive-behavioral program.

Discussion:

The results suggest that an internet-based positive psychology and cognitive-behavioral self-help interventions for the management of chronic pain are clinically useful. Because the self-help exercises as used in the current program do not require therapist involvement, dissemination potential is large. Further studies should examine whether it can best be used as stand-alone or add-on treatment combined with established pain treatment programs.
Automatic Localization of Cochlear Implant Electrode Contacts in CT
Authors: Bennink Edwin , Peters Jeroen P.M. , Wendrich Anne W. , Vonken Evert-jan , van Zanten Gijsbert A. , Viergever Max A.
Published: April 2017

Objectives:

Determining the exact location of cochlear implant (CI) electrode contacts after implantation is important, as it helps quantifying the relation between CI positioning and hearing outcome. Unfortunately, localization of individual contacts can be difficult, because the spacing between the electrode contacts is near the spatial resolution limit of high-resolution clinical computed tomography (CT) scanners. This study introduces and examines a simple, automatic method for the localization of intracochlear electrode contacts. CI geometric specifications may provide the prior knowledge that is essential to accurately estimate contact positions, even though individual contacts may not be visibly resolved.

Design:

The prior knowledge in CI geometry is used to accurately estimate intracochlear electrode contact positions in high-resolution CT scans of seven adult patients implanted with a CI (Cochlear Ltd.). The automatically detected electrode contact locations were verified against locations marked by two experienced observers. The interobserver errors and the errors between the averaged locations and the automatically detected locations were calculated. The estimated contact positions were transformed to a cylindrical cochlear coordinate system, according to an international consensus, in which the insertion angles and the radius and elevation were measured.

Results:

The linear correlation of the automatically detected electrode contact positions with the manually detected locations was high (R
2 = 0.98 for the radius, and R
2 = 1.00 for the insertion angle). The errors in radius and in insertion angle between the automatically detected locations and the manually detected locations were 0.12 mm and 1.7°. These errors were comparable to the interobserver errors. Geometrical measurements were in line with what is usually found in human cochleae. The mean insertion angle of the most apical electrode was 410° (range: 316° to 503°). The mean radius of the electrode contacts in the first turn of the cochlear spiral was 3.0 mm, and the mean radius of the remainder in the second turn was 1.7 mm.

Conclusions:

With implant geometry as prior knowledge, automatic analysis of high-resolution CT scans enables accurate localization of CI electrode contacts. The output of this method can be used to study the effect of CI positioning on hearing outcomes in more detail.
Skeletal assessment with finite element analysis: relevance, pitfalls and interpretation
Authors: Campbell Graeme Michael , Glüer Claus-C.
Published: April 2017

Purpose of review

Finite element models simulate the mechanical response of bone under load, enabling noninvasive assessment of strength. Models generated from quantitative computed tomography (QCT) incorporate the geometry and spatial distribution of bone mineral density (BMD) to simulate physiological and traumatic loads as well as orthopaedic implant behaviour. The present review discusses the current strengths and weakness of finite element models for application to skeletal biomechanics.

Recent findings

In cadaver studies, finite element models provide better estimations of strength compared to BMD. Data from clinical studies are encouraging; however, the superiority of finite element models over BMD measures for fracture prediction has not been shown conclusively, and may be sex and site dependent. Therapeutic effects on bone strength are larger than for BMD; however, model validation has only been performed on untreated bone. High-resolution modalities and novel image processing methods may enhance the structural representation and predictive ability. Despite extensive use of finite element models to study orthopaedic implant stability, accurate simulation of the bone-implant interface and fracture progression remains a significant challenge.

Skeletal finite element models provide noninvasive assessments of strength and implant stability. Improved structural representation and implant surface interaction may enable more accurate models of fragility in the future.
Treatment of Post-Traumatic Femoral Discrepancy With PRECICE Magnetic-Powered Intramedullary Lengthening Nails
Authors: Hammouda Ahmed I. , Jauregui Julio J. , Gesheff Martin G. , Standard Shawn C. , Conway Janet D. , Herzenberg John E.
Published: April 2017

Objective:

To evaluate the outcomes of lengthening post-traumatic femoral segments using a recently available magnetic intramedullary (IM) lengthening system.

Design:

Retrospective cohort study.

Setting:

Urban level II Trauma Center.

Patients/Participants:

Patients treated for post-traumatic femoral shortening at our institution between 2012 and 2015. We identified 17 femurs lengthened (14 men and 3 women). The mean age was 30 years (range, 11–72 years).

Intervention:

Magnetic IM lengthening system.

Main Outcome Measurements:

Amount of lengthening achieved, consolidation index, and complications encountered.

Results:

The mean follow-up was 2.2 years (range, 1–3.7 years). Sixteen patients achieved the planned lengthening, a mean of 3.8 cm (range, 2.3–6.0 cm). Regenerate consolidation occurred at a mean of 119 days (range, 57–209 days). The mean consolidation index was 32 d/cm (range, 16–51 d/cm). Three patients (18%) experienced complications.

Conclusion:

IM lengthening nails are an improvement over external fixators for treatment of post-traumatic femoral shortening. Within certain limits, their use can be extended to problems of limb-length discrepancy with angular/rotational deformity.

Level of Evidence:

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Rheumatoid arthritis and cancer risk∙results from the Greek European prospective investigation into cancer and nutrition cohort
Authors: Klinaki Eleni , Katsoulis Michail , La Vecchia Carlo , Trichopoulou Antonia
Published: April 2017

To investigate the relative risk of cancer development in rheumatoid arthritis (RA) patients in Greece after taking into consideration treatment modalities. The present analysis used data on the medical history of 26 331 participants in the Greek arm of the European Prospective Investigation into Cancer and Nutrition that were collected at enrollment and thereafter during active follow-up. A history of RA and of drug treatment for the disease, as reported at baseline examination, was linked to cases of cancer reported during follow-up. A total of 91 (9.9%) patients with RA developed a cancer compared with 1542 (6.1%) patients without RA. The overall hazard ratios of all cancers increased 25% [95% confidence interval (CI): 1–54] among participants with prevalent RA, and almost all the site-specific incident cancer sites considered had rate ratios above unity. In terms of the contribution of RA medication, the hazard ratios of patients treated with salicylates was close to unity (1.07, 95% CI: 0.69–1.65), whereas those who were not treated with salicylates had a 31% (95% CI: 3–67) increased risk for cancer incidence compared with those without RA at baseline. RA patients have excess cancer risk because of either underlying complex disease pathways or treatment agents targeting immune function. Administration of salicylates appears to reduce the risk of developing malignancies.
Impact of multidisciplinary teams for management of intestinal failure in children
Authors: Belza Christina , Wales Paul W.
Published: April 2017

Purpose of review

To review the recent literature related to the impact of an intestinal rehabilitation program (IRP) on the management of intestinal failure in children.

Recent findings

As publication of a systematic review of pediatric IRPs in 2013, there have been four publications further describing the impact of IRPs in children with intestinal failure. The results continue to support an improvement in survival and enteral autonomy, and a decrease in complications related to liver dysfunction, central venous catheters, and transplantation.

Pediatric IRPs offer significant advantage to outcomes of children with intestinal failure. The literature is difficult to interpret because of methodological limitations. IRP collaboration is necessary to further advance the field.
Recognition of endophyticTrichodermaspecies by leaf-cutting ants and their potential in a Trojan-horse management strategy
Authors: Rocha Silma L. , Evans Harry C. , Jorge Vanessa L. , Cardoso Lucimar A. O. , Pereira Fernanda S. T. , Rocha Fabiano B. , Barreto Robert W. , Hart Adam G. , Elliot Simon L.
Published: April 2017

Interactions between leaf-cutting ants, their fungal symbiont (Leucoagaricus) and the endophytic fungi within the vegetation they carry into their colonies are still poorly understood. If endophytes antagonistic toLeucoagaricuswere found in plant material being carried by these ants, then this might indicate a potential mechanism for plants to defend themselves from leaf-cutter attack. In addition, it could offer possibilities for the management of these important Neotropical pests. Here, we show that, forAtta sexdens rubropilosa, there was a significantly greater incidence ofTrichodermaspecies in the vegetation removed from the nests—and deposited around the entrances—than in that being transported into the nests. In a no-choice test,Trichoderma-infested rice was taken into the nest, with deleterious effects on both the fungal gardens and ant survival. The endophytic ability of selected strains ofTrichodermawas also confirmed, following their inoculation and subsequent reisolation from seedlings of eucalyptus. These results indicate that endophytic fungi which pose a threat to ant fungal gardens through their antagonistic traits, such asTrichoderma, have the potential to act as bodyguards of their plant hosts and thus might be employed in a Trojan-horse strategy to mitigate the negative impact of leaf-cutting ants in both agriculture and silviculture in the Neotropics. We posit that the ants would detect and evict such ‘malign’ endophytes—artificially inoculated into vulnerable crops—during the quality-control process within the nest, and, moreover, that the foraging ants may then be deterred from further harvesting of ‘Trichoderma-enriched’ plants.
Modelling the impact of curtailing antibiotic usage in food animals on antibiotic resistance in humans
Authors: van Bunnik B. A. D. , Woolhouse M. E. J.
Published: April 2017

Consumption of antibiotics in food animals is increasing worldwide and is approaching, if not already surpassing, the volume consumed by humans. It is often suggested that reducing the volume of antibiotics consumed by food animals could have public health benefits. Although this notion is widely regarded as intuitively obvious there is a lack of robust, quantitative evidence to either support or contradict the suggestion. As a first step towards addressing this knowledge gap, we develop a simple mathematical model for exploring the generic relationship between antibiotic consumption by food animals and levels of resistant bacterial infections in humans. We investigate the impact of restricting antibiotic consumption by animals and identify which model parameters most strongly determine that impact. Our results suggest that, for a wide range of scenarios, curtailing the volume of antibiotics consumed by food animals has, as a stand-alone measure, little impact on the level of resistance in humans. We also find that reducing the rate of transmission of resistance from animals to humans may be more effective than an equivalent reduction in the consumption of antibiotics in food animals. Moreover, the response to any intervention is strongly determined by the rate of transmission from humans to animals, an aspect which is rarely considered.
Octonions in random matrix theory
Authors: Forrester Peter J.
Published: April 2017

The octonions are one of the four normed division algebras, together with the real, complex and quaternion number systems. The latter three hold a primary place in random matrix theory, where in applications to quantum physics they are determined as the entries of ensembles of Hermitian random matrices by symmetry considerations. Only forN=2 is there an existing analytic theory of Hermitian random matrices with octonion entries. We use a Jordan algebra viewpoint to provide an analytic theory forN=3. We then proceed to consider the matrix structureX†X, whenXhas random octonion entries. Analytic results are obtained fromN=2, but are observed to break down in the 3×3 case.
Modelling nonlinear electrohydrodynamic surface waves over three-dimensional conducting fluids
Authors: Wang Zhan
Published: April 2017

The evolution of the free surface of a three-dimensional conducting fluid in the presence of gravity, surface tension and vertical electric field due to parallel electrodes, is considered. Based on the analysis of the Dirichlet–Neumann operators, a series of fully nonlinear models is derived systematically from the Euler equations in the Hamiltonian framework without assumptions on competing length scales can therefore be applied to systems of arbitrary fluid depth and to disturbances with arbitrary wavelength. For special cases, well-known weakly nonlinear models in shallow and deep fluids can be generalized via introducing extra electric terms. It is shown that the electric field has a great impact on the physical system and can change the qualitative nature of the free surface: (i) when the separation distance between two electrodes is small compared with typical wavelength, the Boussinesq, Benney–Luke (BL) and Kadomtsev–Petviashvili (KP) equations with modified coefficients are obtained, and electric forces can turn KP-I to KP-II and vice versa; (ii) as the parallel electrodes are of large separation distance but the thickness of the liquid is much smaller than typical wavelength, we generalize the BL and KP equations by adding pseudo-differential operators resulting from the electric field; (iii) for a quasi-monochromatic plane wave in deep fluid, we derive the cubic nonlinear Schrödinger (NLS) equation, but its type (focusing or defocusing) is strongly influenced by the value of the electric parameter. For sufficient surface tension, numerical studies reveal that lump-type solutions exist in the aforementioned three regimes. Particularly, even when the associated NLS equation is defocusing for a wave train, lumps can exist in fully nonlinear models.
Soft phononic crystals with deformation-independent band gaps
Authors: Zhang Pu , Parnell William J.
Published: April 2017

Soft phononic crystals have the advantages over their stiff counterparts of being flexible and reconfigurable. Normally, the band gaps of soft phononic crystals will be modified after deformation due to both geometric and constitutive nonlinearity. Indeed these are important properties that can be exploited to tune the dynamic properties of the material. However, in some instances, it may be that one wishes to deform the medium while retaining the band gap structure. A special class of soft phononic crystals is described here with band gaps that are independent or almost-independent of the imposed mechanical deformation, which enables the design of phononic crystals with robust performance. This remarkable behaviour originates from transformation elasticity theory, which leaves the wave equation and the eigenfrequencies invariant after deformation. The necessary condition to achieve such a property is that the Lagrangian elasticity tensor of the hyperelastic material should be constant, i.e. independent of deformation. It is demonstrated that incompressible neo-Hookean materials exhibit such a unique property. Semilinear materials also possess this property under special loading conditions. Phononic crystals composed of these two materials are studied theoretically and the predictions of invariance, or the manner in which the response deviates from invariance, are confirmed via numerical simulation.
Does a better model yield a better argument? An info-gap analysis
Authors: Ben-Haim Yakov
Published: April 2017

Theories, models and computations underlie reasoned argumentation in many areas. The possibility of error in these arguments, though of low probability, may be highly significant when the argument is used in predicting the probability of rare high-consequence events. This implies that the choice of a theory, model or computational method for predicting rare high-consequence events must account for the probability of error in these components. However, error may result from lack of knowledge or surprises of various sorts, and predicting the probability of error is highly uncertain. We show that the putatively best, most innovative and sophisticated argument may not actually have the lowest probability of error. Innovative arguments may entail greater uncertainty than more standard but less sophisticated methods, creating an innovation dilemma in formulating the argument. We employ info-gap decision theory to characterize and support the resolution of this problem and present several examples.
Microstructure-based hyperelastic models for closed-cell solids
Authors: Mihai L. Angela , Wyatt Hayley , Goriely Alain
Published: April 2017

For cellular bodies involving large elastic deformations, mesoscopic continuum models that take into account the interplay between the geometry and the microstructural responses of the constituents are developed, analysed and compared with finite-element simulations of cellular structures with different architecture. For these models, constitutive restrictions for the physical plausibility of the material responses are established, and global descriptors such as nonlinear elastic and shear moduli and Poisson’s ratio are obtained from the material characteristics of the constituents. Numerical results show that these models capture well the mechanical responses of finite-element simulations for three-dimensional periodic structures of neo-Hookean material with closed cells under large tension. In particular, the mesoscopic models predict the macroscopic stiffening of the structure when the stiffness of the cell-core increases.
Astronomical and atmospheric impacts on deep-sea hydrothermal vent invertebrates
Authors: Lelièvre Yann , Legendre Pierre , Matabos Marjolaine , Mihály Steve , Lee Raymond W. , Sarradin Pierre-Marie , Arango Claudia P. , Sarrazin Jozée
Published: April 2017

Ocean tides and winter surface storms are among the main factors driving the dynamics and spatial structure of marine coastal species, but the understanding of their impact on deep-sea and hydrothermal vent communities is still limited. Multidisciplinary deep-sea observatories offer an essential tool to study behavioural rhythms and interactions between hydrothermal community dynamics and environmental fluctuations. Here, we investigated whether species associated with a
Ridgeia piscesae
tubeworm vent assemblage respond to local ocean dynamics. By tracking variations in vent macrofaunal abundance at different temporal scales, we provide the first evidence that tides and winter surface storms influence the distribution patterns of mobile and non-symbiotic hydrothermal species (i.e. pycnogonids
Sericosura
sp. and Polynoidae polychaetes) at more than 2 km depth. Local ocean dynamics affected the mixing between hydrothermal fluid inputs and surrounding seawater, modifying the environmental conditions in vent habitats. We suggest that hydrothermal species respond to these habitat modifications by adjusting their behaviour to ensure optimal living conditions. This behaviour may reflect a specific adaptation of vent species to their highly variable habitat.
Hummingbird pollination and the diversification of angiosperms: an old and successful association in Gesneriaceae
Authors: Serrano-Serrano Martha Liliana , Rolland Jonathan , Clark John L. , Salamin Nicolas , Perret Mathieu
Published: April 2017

The effects of specific functional groups of pollinators in the diversification of angiosperms are still to be elucidated. We investigated whether the pollination shifts or the specific association with hummingbirds affected the diversification of a highly diverse angiosperm lineage in the Neotropics. We reconstructed a phylogeny of 583 species from the Gesneriaceae family and detected diversification shifts through time, inferred the timing and amount of transitions among pollinator functional groups, and tested the association between hummingbird pollination and speciation and extinction rates. We identified a high frequency of pollinator transitions, including reversals to insect pollination. Diversification rates of the group increased through time since 25 Ma, coinciding with the evolution of hummingbird-adapted flowers and the arrival of hummingbirds in South America. We showed that plants pollinated by hummingbirds have a twofold higher speciation rate compared with plants pollinated by insects, and that transitions among functional groups of pollinators had little impact on the diversification process. We demonstrated that floral specialization on hummingbirds for pollination has triggered rapid diversification in the Gesneriaceae family since the Early Miocene, and that it represents one of the oldest identified plant–hummingbird associations. Biotic drivers of plant diversification in the Neotropics could be more related to this specific type of pollinator (hummingbirds) than to shifts among different functional groups of pollinators.
Eye development in the four-eyed fish
Anableps anableps
: cranial and retinal adaptations to simultaneous aerial and aquatic vision
Authors: Perez Louise N. , Lorena Jamily , Costa Carinne M. , Araujo Maysa S. , Frota-Lima Gabriela N. , Matos-Rodrigues Gabriel E. , Martins Rodrigo A. P. , Mattox George M. T. , Schneider Patricia N.
Published: April 2017

The unique eyes of the four-eyed fish
Anableps anableps
have long intrigued biologists. Key features associated with the bulging eye of
Anableps
include the expanded frontal bone and the duplicated pupils and cornea. Furthermore, the
Anableps
retina expresses different photoreceptor genes in dorsal and ventral regions, potentially associated with distinct aerial and aquatic stimuli. To gain insight into the developmental basis of the
Anableps
unique eye, we examined neurocranium and eye ontogeny, as well as photoreceptor gene expression during larval stages. First, we described six larval stages during which duplication of eye structures occurs. Our osteological analysis of neurocranium ontogeny revealed another distinctive Anablepid feature: an ossified interorbital septum partially separating the orbital cavities. Furthermore, we identified the onset of differences in cell proliferation and cell layer density between dorsal and ventral regions of the retina. Finally, we show that differential photoreceptor gene expression in the retina initiates during development, suggesting that it is inherited and not environmentally determined. In sum, our results shed light on the ontogenetic steps leading to the highly derived
Anableps
eye.
Risky business for a juvenile marine predator? Testing the influence of foraging strategies on size and growth rate under natural conditions
Authors: Hussey Nigel E. , DiBattista Joseph D. , Moore Jonathan W. , Ward Eric J. , Fisk Aaron T. , Kessel Steven , Guttridge Tristan L. , Feldheim Kevin A. , Franks Bryan R. , Gruber Samuel H. , Weideli Ornella C. , Chapman Demian D.
Published: April 2017

Mechanisms driving selection of body size and growth rate in wild marine vertebrates are poorly understood, thus limiting knowledge of their fitness costs at ecological, physiological and genetic scales. Here, we indirectly tested whether selection for size-related traits of juvenile sharks that inhabit a nursery hosting two dichotomous habitats, protected mangroves (low predation risk) and exposed seagrass beds (high predation risk), is influenced by their foraging behaviour. Juvenile sharks displayed a continuum of foraging strategies between mangrove and seagrass areas, with some individuals preferentially feeding in one habitat over another. Foraging habitat was correlated with growth rate, whereby slower growing, smaller individuals fed predominantly in sheltered mangroves, whereas larger, faster growing animals fed over exposed seagrass. Concomitantly, tracked juveniles undertook variable movement behaviours across both the low and high predation risk habitat. These data provide supporting evidence for the hypothesis that directional selection favouring smaller size and slower growth rate, both heritable traits in this shark population, may be driven by variability in foraging behaviour and predation risk. Such evolutionary pathways may be critical to adaptation within predator-driven marine ecosystems.
Father Absence and Accelerated Reproductive Development
Authors: Gaydosh Lauren , Belsky Daniel W. , Domingue Benjamin W. , Boardman Jason D. , Harris Kathleen Mullan
Published: April 2017

Evidence shows that girls who experience father absence in childhood experience accelerated reproductive development in comparison to peers with present fathers. One hypothesis advanced to explain this empirical pattern is genetic confounding, wherein gene-environment correlation (rGE) causes a spurious relationship between father absence and reproductive timing. We test this hypothesis by constructing polygenic scores for age at menarche and first birth using recently available genome wide association study results and molecular genetic data on a sample of non-Hispanic white females from the National Longitudinal Study of Adolescent to Adult Health. Young women’s accelerated menarche polygenic scores were unrelated to their exposure to father absence. In contrast, earlier first-birth polygenic scores tended to be higher in young women raised in homes with absent fathers. Nevertheless, father absence and the polygenic scores independently and additively predict reproductive timing. We find limited evidence in support of the gene-environment correlation hypothesis.
Sex differences in the adult human brain: Evidence from 5,216 UK Biobank participants
Authors: Ritchie Stuart J. , Cox Simon R. , Shen Xueyi , Lombardo Michael V. , Reus Lianne M. , Alloza Clara , Harris Mathew A. , Alderson Helen L. , Hunter Stuart , Neilson Emma , Liewald David C. M. , Auyeung Bonnie , Whalley Heather C. , Lawrie Stephen M. , Gale Catharine R. , Bastin Mark E. , McIntosh Andrew M. , Deary Ian J.
Published: April 2017

Sex differences in the human brain are of interest, for example because of sex differences in the observed prevalence of psychiatric disorders and in some psychological traits. We report the largest single-sample study of structural and functional sex differences in the human brain (2,750 female, 2,466 male participants; 44-77 years). Males had higher volumes, surface areas, and white matter fractional anisotropy; females had thicker cortices and higher white matter tract complexity. There was considerable distributional overlap between the sexes. Subregional differences were not fully attributable to differences in total volume or height. There was generally greater male variance across structural measures. Functional connectome organization showed stronger connectivity for males in unimodal sensorimotor cortices, and stronger connectivity for females in the default mode network. This large-scale study provides a foundation for attempts to understand the causes and consequences of sex differences in adult brain structure and function.
Reducing gravity takes the bounce out of running
Authors: Polet Delyle T. , Schroeder Ryan T. , Bertram John E. A.
Published: April 2017

In gravity below Earth normal, a person should be able to take higher leaps in running. We asked ten subjects to run on a treadmill in five levels of simulated reduced gravity and optically tracked center of mass kinematics. Subjects consistentlyreducedballistic height compared to running in normal gravity. We explain this trend by considering the vertical takeoff velocity (defined as maximum vertical velocity). Energetically optimal gaits should balance energetic costs of ground-contact collisions (favouring lower takeoff velocity), and step frequency penalties such as leg swing work (favouring higher takeoff velocity, but less so in reduced gravity). Measured vertical takeoff velocity scaled with the square root of gravitational acceleration, following energetic optimality predictions and explaining why ballistic height decreases in lower gravity. The success of work-based costs in predicting this behaviour challenges the notion that gait adaptation in reduced gravity results from an unloading of the stance phase. Only the relationship between takeoff velocity and swing cost changes in reduced gravity; the energetic cost of the down-to-up transition for a given vertical takeoff velocity does not change with gravity. Because lower gravity allows an elongated swing phase for a given takeoff velocity, the motor control system can relax the vertical momentum change in the stance phase, so reducing ballistic height, without great energetic penalty to leg swing work. While it may seem counterintuitive, using less “bouncy” gaits in reduced gravity is a strategy to reduce energetic costs, to which humans seem extremely sensitive.

Summary Statement

During running, humans take higher leaps in normal gravity than in reduced gravity, in order to optimally balance the competing costs of stance and leg-swing work.