bluuebunny/crossref_metadata_2025 huggingface dataset:
Transport properties of a few nanometer-thick TiSe2 films grown by molecular-beam epitaxy
Authors: Wang Yue , Nakano Masaki , Kashiwabara Yuta , Matsuoka Hideki , Iwasa Yoshihiro
Published: August 2018

Layered materials are known to exhibit a variety of charge-density wave (CDW) phases due to their quasi-two dimensional nature. Of particular interest is the CDW phase in a prototypical layered transition-metal dichalcogenide (TMDC) TiSe2, where the CDW is known to form with commensurate 2a × 2a × 2c structural distortion at T = 200 K (where a and c are the lattice parameters). Recent experimental studies have revealed intriguing aspects of this material as represented by the emergence of superconductivity upon electron doping and possible existence of the excitonic insulator phase, making TiSe2 attractive as a model material for investigation of collective phenomena in TMDC. However, the evolution of the CDW phase at nanometer-scale thickness, at least below 10 monolayers (6 nm), has not been well investigated yet, in particular from transport viewpoints, presumably due to difficulty in fabrication of such ultrathin samples by conventional approaches. Here, we report the transport properties of a few nanometer-thick highly crystalline TiSe2 epitaxial thin films grown on insulating Al2O3 substrates by molecular-beam epitaxy, demonstrating robust CDW transitions down to 5 monolayers (3 nm). We also clarify an interesting aspect of van der Waals epitaxy, a “self-rotational” growth without strain, which should be realized only in a system having a weak substrate-film interaction.
Inductively coupled 30 T magnetic field platform for magnetized high-energy-density plasma studies
Authors: Fiksel G. , Backhus R. , Barnak D. H. , Chang P.-Y. , Davies J. R. , Jacobs-Perkins D. , McNally P. , Spielman R. B. , Viges E. , Betti R.
Published: August 2018

A pulsed high magnetic field device based on the inductively coupled coil concept [D. H. Barnak et al., Rev. Sci. Instrum. 89, 033501 (2018)] is described. The device can be used for studying magnetized high-energy-density plasma and is capable of producing a pulsed magnetic field of 30 T inside a single-turn coil with an inner diameter of 6.5 mm and a length of 6.3 mm. The magnetic field is created by discharging a high-voltage capacitor through a multi-turn solenoid, which is inductively coupled to a small single-turn coil. The solenoid electric current pulse of tens of kA and a duration of several μs is inductively transformed to hundreds of kA in the single-turn coil, thus enabling a high magnetic field. Unlike directly driven single-turn systems that require a high-current and low-inductive power supply, the inductively coupled system operates using a relatively low-current power supply with very relaxed requirements for its inductance. This arrangement significantly simplifies the design of the power supply and also makes it possible to place the power supply at a significant distance from the coil. In addition, the device is designed to contain possible wire debris, which makes it attractive for debris-sensitive applications.
Effect of structural disorder on transport properties of LaNiO3 thin films
Authors: Kumar Yogesh , Bhatt Harsh , Prajapat C. L. , Poswal H. K. , Basu S. , Singh Surendra
Published: August 2018

We have deposited LaNiO3 thin films on LaAlO3 (001), SrTiO3 (001), and Si (001) substrates using the pulsed laser deposition technique. Depositions were carried out at various substrate temperatures ranging from 0 to 800 °C. The effects of lattice mismatch and structural disorder on the transport properties of films deposited on various substrates and at different substrate temperatures are reported. X-ray diffraction confirms a highly c-axis oriented growth of LaNiO3 films on all the substrates at substrate temperatures of 600 and 800 °C, while at lower substrate temperatures deposited films are amorphous. Emergence of a new Raman mode indicates symmetry lowering in all the deposited crystalline films. Hardening of the Eg(3) (∼400 cm−1) mode is also observed with the rise of in-plane compressive strain. Resistivity curves for films on Si show a semiconducting behaviour and follow a variable range hopping mechanism. Crystalline films on LaAlO3 and SrTiO3 exhibit a metallic character along with a low-temperature resistivity upturn, which is attributed to the contribution of self-localization to resistivity at low temperatures as indicated by magnetotransport measurements.
Angle dependent localized surface plasmon resonance from near surface implanted silver nanoparticles in SiO2 thin film
Authors: Bommali R. K. , Mahapatra D. P. , Gupta H. , Guha Puspendu , Topwal D. , Vijaya Prakash G. , Ghosh S. , Srivastava P.
Published: August 2018

Near surface silver nanoparticles embedded in silicon oxide were obtained by 40 keV silver negative ion implantation without the requirement of an annealing step. Ion beam induced local heating within the film leads to an exodiffusion of the silver ions towards the film surface, resulting in the protrusion of larger nanoparticles. Cross-sectional transmission electron microscopy reveals the presence of poly-disperse nanoparticles (NPs), ranging between 2 nm and 20 nm, at different depths of the SiO2 film. The normal incidence reflectance spectrum shows a double kink feature in the vicinity of 400 nm, indicating a strong localized surface plasmon resonance (LSPR) from the embedded NPs. However, due to overlap of the bilayer interference and LSPR, the related features are difficult to separate. The ambiguity in associating the correct kink with the LSPR related absorption is cleared with the use of transfer matrix simulations in combination with an effective medium approximation. The simulations are further verified with angle dependent reflectance measurements. Additionally, transfer matrix simulation is also used to calculate the electric field intensity profile through the depth of the film, wherein an enhanced electric field intensity is predicted at the surface of the implanted films.
Explosion of the thick metallic surface during ultrafast rise of a multimegagauss magnetic field
Authors: Sorokin S. A.
Published: August 2018

The technique of producing a multimegagauss magnetic field on the surface of a cylindrical conductor with a rise time of less than 1 ns has been examined experimentally on a high-current generator with a peak current of about 2 MA. In experiments in the conductor region, a plasma with a density of 1016–1017 cm−3 is preliminarily injected. A fast increase in the magnetic field on the conductor surface occurs, as the J × B force sweeps up the injected plasma in the axial and radial directions. It is observed that such a high rise-rate of the field is accompanied by an explosion of the current skin layer with the formation of a surface layer of a dense high-temperature plasma and a powerful pulse of soft x-ray radiation. The measured power of radiation emitted from the surface of a 1.1-mm diameter tungsten rod is 0.7 TW/cm, which corresponds to a blackbody temperature of about 65 eV.
Asymmetric interplay leads to robust coexistence by means of a global attractor in the spatial dynamics of cyclic competition
Authors: Park Junpyo
Published: August 2018

In the past decade, there have been many efforts to understand the species interplay with biodiversity in cyclic games within the macro and microscopic levels. In this direction, mobility and intraspecific competition have been found to be the main factors promoting coexistence in spatially extended systems. In this paper, we explore the relevant effect of asymmetric competitions coupled with mobility on the coexistence of cyclically competing species. By examining the coexistence probability, we have found that mobility can facilitate coexistence in the limited cases of asymmetric competition and can be well predicted by the basin structure of the deterministic system. In addition, it is found that mobility can have beneficial and harmful effects on coexistence when all competitions occur asymmetrically. We also found that the coexistence in the spatial dynamics ultimately becomes a global attractor. We hope to provide insights into the associated effects of asymmetric interplays on species coexistence in a spatially extended system and understand the biodiversity of asymmetrically competitive species under more complex competition structures.
Alkyne-Substituted Fimbrolide Analogues as Novel Bacterial Quorum-Sensing Inhibitors
Authors: Biswas Nripendra Nath , Iskander George M. , Mielczarek Marcin , Yu Tsz Tin , Black David StC , Kumar Naresh
Published: August 2018

Gram-negative bacteria such as Pseudomonas aeruginosa use furanosyl diesters as autoinducers for quorum sensing (QS), a major regulatory and cell-to-cell communication system for social adaptation, virulence factor production, biofilm formation, and antibiotic resistance. A range of natural and synthetic brominated furanones, i.e. fimbrolide derivatives, have been found to act as inhibitors of QS-dependent bacterial phenotypes, complementing the bactericidal ability of traditional antibiotics. In this work, several novel acetylene analogues of fimbrolides were synthesised in moderate to high yields via Sonogashira coupling reactions of brominated furanones 4-bromo-5-(bromomethylene)furan-2(5H)-one 4 and 5-(dibromomethylene)-3-ethylfuran-2(5H)-one 5. The Sonogashira reaction of acetylenes on 4-bromo-5-(bromomethylene)furan-2(5H)-one 4 was favoured at the C5 methylene bromide over the C4 bromide substituent. On biological testing, the most potent compounds 13 and 14 showed 82 and 98 % bacterial quorum-sensing inhibitory (QSI) activity against Pseudomonas aeruginosa reporter strain respectively.
Recurrent computations for visual pattern completion
Authors: Tang Hanlin , Schrimpf Martin , Lotter William , Moerman Charlotte , Paredes Ana , Ortega Caro Josue , Hardesty Walter , Cox David , Kreiman Gabriel
Published: August 2018

Significance

The ability to complete patterns and interpret partial information is a central property of intelligence. Deep convolutional network architectures have proved successful in labeling whole objects in images and capturing the initial 150 ms of processing along the ventral visual cortex. This study shows that human object recognition abilities remain robust when only small amounts of information are available due to heavy occlusion, but the performance of bottom-up computational models is impaired under limited visibility. The results provide combined behavioral, neurophysiological, and modeling insights showing how recurrent computations may help the brain solve the fundamental challenge of pattern completion.
Recycled ancient ghost carbonate in the Pitcairn mantle plume
Authors: Wang Xiao-Jun , Chen Li-Hui , Hofmann Albrecht W. , Hanyu Takeshi , Kawabata Hiroshi , Zhong Yuan , Xie Lie-Wen , Shi Jin-Hua , Miyazaki Takashi , Hirahara Yuka , Takahashi Toshiro , Senda Ryoko , Chang Qing , Vaglarov Bogdan S. , Kimura Jun-Ichi
Published: August 2018

Significance

Lavas from Pitcairn Island are the best candidates for exploring the origin of the enigmatic EM1 component found in some mantle plumes because they show the most extreme isotopic compositions of Sr, Nd, Hf, and Pb that define the EM1 component. We find that these lavas have the lowest δ
26
Mg values so far recorded in oceanic basalts. Subducted late Archean dolomite-bearing sediments are the most plausible source of the low-δ
26
Mg feature of Pitcairn lavas. This requires that an ancient, originally sedimentary component has been emplaced near the core–mantle boundary to ultimately become part of the Pitcairn plume source.
Evolution and function of the hominin forefoot
Authors: Fernández Peter J. , Mongle Carrie S. , Leakey Louise , Proctor Daniel J. , Orr Caley M. , Patel Biren A. , Almécija Sergio , Tocheri Matthew W. , Jungers William L.
Published: August 2018

Significance

A critical step in the evolutionary history leading to the origins of humankind was the adoption of habitual bipedal locomotion by our hominin ancestors. We have identified novel bony shape variables in the forefoot across extant anthropoids and extinct hominins that are linked functionally to the emergence of bipedal walking. Results indicate a consistent and generalizable pattern in hominin pedal evolution that spans from
Ardipithecus
to early
Homo
—the relatively late derivation of a modern hallux in comparison with the lateral rays. These data provide novel morphological and macroevolutionary evidence for how and when the hominin pedal skeleton evolved to accommodate the unique biomechanical demands of bipedalism.
Testing for crowd out in social nudges: Evidence from a natural field experiment in the market for electricity
Authors: Brandon Alec , List John A. , Metcalfe Robert D. , Price Michael K. , Rundhammer Florian
Published: August 2018

This study considers the response of household electricity consumption to social nudges during peak load events. Our investigation considers two social nudges. The first targets conservation during peak load events, while the second promotes aggregate conservation. Using data from a natural field experiment with 42,100 households, we find that both social nudges reduce peak load electricity consumption by 2 to 4% when implemented in isolation and by nearly 7% when implemented in combination. These findings suggest an important role for social nudges in the regulation of electricity markets and a limited role for crowd out effects.
RNF169 limits 53BP1 deposition at DSBs to stimulate single-strand annealing repair
Authors: An Liwei , Dong Chao , Li Junshi , Chen Jie , Yuan Jingsong , Huang Jun , Chan Kui Ming , Yu Cheng-han , Huen Michael S. Y.
Published: August 2018

Significance

53BP1 restrains DNA end resection, and its dosage imbalance upsets DNA double-strand break (DSB) repair pathway choice. Here, by monitoring 53BP1 distribution on DSB-flanking chromatin, we have established a dose-dependent role of the RING finger protein RNF169 in limiting 53BP1 DSB deposition. Moreover, we found that forced expression of RNF169 overcomes 53BP1 activity and stimulates mutagenic DSB repair via the single-strand annealing pathway. Our findings suggest that aberrant expression of RNF169 may represent a deleterious factor in DSB repair control and in maintenance of genome stability.
Probing the non-Debye low-frequency excitations in glasses through random pinning
Authors: Angelani Luca , Paoluzzi Matteo , Parisi Giorgio , Ruocco Giancarlo
Published: August 2018

Significance

Amorphous solids are continuum media. However, their mechanical and thermodynamical properties, even though universal, dramatically deviate from those in crystalline solids. Their anomalous behavior reflects peculiar and universal deviations from Debye’s law in the low-frequency sector of the density of states

D

(

ω

)

. Theoretical models predict a population of non-Goldstone modes following the universal power law

D

(

ω

)

∼

ω

4

that are subdominant and therefore hard to detect. In this work, we introduce a general protocol that can be used in both numerical simulations and experiments, to probe the non-Debye portion of the spectrum.
JUM is a computational method for comprehensive annotation-free analysis of alternative pre-mRNA splicing patterns
Authors: Wang Qingqing , Rio Donald C.
Published: August 2018

Significance

Alternative pre-mRNA splicing (AS) is a critical gene regulatory mechanism to produce diverse, tissue-specific, and functionally distinct protein profiles in eukaryotes to maintain normal cellular functions. Aberrant AS patterns are constantly associated with many human diseases, including cancer. The exceptional complexity of AS imposes a major challenge to analyzing AS across various tissues and cell types. Here we present a computational algorithm to profile and quantitate tissue-specific AS profiles from RNA-sequencing data without any prior knowledge of the host transcriptome. The junction usage model shows consistent superior performance in both specificity and sensitivity compared with other currently available AS analysis methods, and can be readily applied to a wide range of RNA samples from different organisms for accurate and comprehensive analyses of AS.
Deep mutational scanning of hemagglutinin helps predict evolutionary fates of human H3N2 influenza variants
Authors: Lee Juhye M. , Huddleston John , Doud Michael B. , Hooper Kathryn A. , Wu Nicholas C. , Bedford Trevor , Bloom Jesse D.
Published: August 2018

Significance

A key goal in the study of influenza virus evolution is to forecast which viral strains will persist and which ones will die out. Here we experimentally measure the effects of all amino acid mutations to the hemagglutinin protein from a human H3N2 influenza strain on viral growth in cell culture. We show that these measurements have utility for distinguishing among viral strains that do and do not succeed in nature. Overall, our work suggests that new high-throughput experimental approaches may be useful for understanding virus evolution in nature.
Discovery of fissionogenic Cs and Ba capture five years after Oklo reactor shutdown
Authors: Groopman Evan E. , Willingham David G. , Meshik Alex P. , Pravdivtseva Olga V.
Published: August 2018

Significance

The Oklo natural nuclear reactors provide a wealth of information regarding the migration and retention of fission products in nuclear wastes. Radioactive volatile and gaseous elements easily escape from reactor fuel into the environment without proper containment. Cesium, in particular, represents a significant environmental and health hazard. Here, we used an isotope imaging system to identify the location of sequestered fissionogenic Cs and Ba in Oklo. Cesium and Ba were captured in Ru metal/sulfide aggregates shortly after reactor criticality ceased. These elements were otherwise nearly completely lost from the reactor. We have further discovered the most depleted natural U on Earth, indicating that these fission products were retained in the most active region of the reactor.
The consequences of cavity creation on the folding landscape of a repeat protein depend upon context
Authors: Jenkins Kelly A. , Fossat Martin J. , Zhang Siwen , Rai Durgesh K. , Klein Sean , Gillilan Richard , White Zackary , Gerlich Grayson , McCallum Scott A. , Winter Roland , Gruner Sol M. , Barrick Doug , Royer Catherine A.
Published: August 2018

Significance

Extant protein sequences are the result of evolutionary pressure. Eliminating core packing interactions by mutation, regardless of position, generally results in similar perturbations to global stability. In contrast, we find that cavity creation has highly varied consequences for a protein folding landscape, depending upon the context in which the cavities are introduced. These observations have implications for interpreting evolutionary adaptation, as it is likely that proteins have evolved to exhibit optimal levels of conformational heterogeneity and dynamics. These results should also inform protein engineering efforts, as they provide insight into how sequence can modulate the population of functionally important excited states, as well as states that lead to secondary, undesirable reactions such as oligomerization, aggregation, surface activity, and phase separation.
Phosphoinositides control the localization of HOPS subunit VPS41, which together with VPS33 mediates vacuole fusion in plants
Authors: Brillada Carla , Zheng Jiameng , Krüger Falco , Rovira-Diaz Eliezer , Askani Jana Christin , Schumacher Karin , Rojas-Pierce Marcela
Published: August 2018

Significance

Plant vacuoles are essential organelles and occupy up to 90% of the cell volume. Their roles include regulation of stomata movements, protein storage in seeds, gravity sensing, and ion homeostasis. Vacuole or lysosome fusion in eukaryotes is mediated by two multisubunit complexes, SNARE and homotypic fusion and vacuolar protein sorting (HOPS), but only the SNARE complex is well characterized in plants. Here, we show that, similar to other eukaryotes, HOPS mediates vacuole fusion in plants by interaction with SNAREs and that the HOPS subunit VPS33 and the SNARE protein SYP22 display the sites for interaction between these complexes. In contrast to other eukaryotes, however, plant HOPS recruitment to liposomes is inhibited by phosphoinositides, which appear to define strict rules for regulating fusion and fragmentation of dynamic vacuoles.
Structural and mechanistic analysis of the arsenate respiratory reductase provides insight into environmental arsenic transformations
Authors: Glasser Nathaniel R. , Oyala Paul H. , Osborne Thomas H. , Santini Joanne M. , Newman Dianne K.
Published: August 2018

Significance

Microbial arsenate respiration enhances the mobility of arsenic and contributes to the poisoning of tens of millions of people worldwide. Our ability to quantitatively predict how microbial activities shape arsenic geochemistry depends on a detailed understanding of how the enzymes that catalyze arsenate reduction work under environmentally relevant conditions. The structural and kinetic findings of the Arr enzyme complex reported here both help rationalize its extracytoplasmic localization and allow us to predict that the rate of arsenate release from minerals likely constrains its activity in sedimentary environments. Moreover, this work illustrates that engineering environmental bacteria to overexpress their native proteins can be straightforward, a strategy that may advance the study of enzymes that are challenging to express in traditional hosts.
Mre11 complex links sister chromatids to promote repair of a collapsed replication fork
Authors: Zhu Min , Zhao Hongchang , Limbo Oliver , Russell Paul
Published: August 2018

Significance

When replication forks collapse at single-strand DNA breaks, the resulting single-ended DNA double-strand breaks (seDSBs) are repaired by sister chromatid recombination (SCR). The Mre11–Rad50–Nbs1 (MRN) protein complex and CtIP/Ctp1 nucleolytically resect the seDSB to initiate SCR, but MRN was also proposed to promote SCR by tethering the seDSB to the unbroken sister chromatid. Here, we show that MRN sequentially localizes with the seDSB and sister chromatid during SCR. Provision of an intrachromosomal repair template alleviates the requirement for the nonnucleolytic function of MRN in repair of a collapsed replication fork. Zinc-coordinating “hooks” in Rad50 that are linchpins for MRN intercomplexes are essential for SCR. These studies support the MRN tethering hypothesis.
Designing antiphase boundaries by atomic control of heterointerfaces
Authors: Wang Zhen , Guo Hangwen , Shao Shuai , Saghayezhian Mohammad , Li Jun , Fittipaldi Rosalba , Vecchione Antonio , Siwakoti Prahald , Zhu Yimei , Zhang Jiandi , Plummer E. W.
Published: August 2018

Significance

The mechancial and transport properties of every material are intimately coupled to the generation and formation of defects. In many systems, the nucleation process of defects is highly unpredictable due to the multiple coexisting nucleation mechanisms. A strategy to design and manipulate defect nucleation and formation can improve our understanding and in principle lead to the ability to control performance. Here we present a simple approach of designing 2D defects—named antiphase boundaries—using an atomic-controlled high-quality interface. These defects have a well-defined origin, location, and nucleation mechanism. Via advanced synthesis technology, atomically resolved electron microscopy, and theory, we reveal that these defects display distinctive properties such as physical merging and antipolar structural phases to potentially achieve memory devices.
Silkworm genetic sexing through W chromosome-linked, targeted gene integration
Authors: Zhang Zhongjie , Niu Baolong , Ji Dongfeng , Li Muwang , Li Kai , James Anthony A. , Tan Anjiang , Huang Yongping
Published: August 2018

Significance

Insect sex is determined genetically and shows high diversity among different species. The silkworm,
Bombyx mori
, has a WZ/ZZ sex chromosome system seen in lepidopteran insects in which the females are heterogametic. Sex separation methods are critical for commercial aspects of rearing silkworms, and genetic-sexing systems also could serve as the basis for adaptation to sterile insect techniques for pest lepidopteran species. Here, we describe a W chromosome-based, genetic-sexing system combining transcriptional activator-like effector nucleases and CRISPR/Cas9 technologies in
B. mori
. Development of silkworm strains with ubiquitous female-specific fluorescence for convenient genetic sorting or complete female-specific embryonic lethality for male-only rearing provides a successful example of targeting an insect sex chromosome with genome editing tools, which should assist future sterile insect technique development for pest insects.
Maternal Folic Acid Supplementation During Pregnancy Promotes Neurogenesis and Synaptogenesis in Neonatal Rat Offspring
Authors: Wang Xinyan , Li Wen , Li Zhenshu , Ma Yue , Yan Jing , Wilson John X , Huang Guowei
Published: August 2018

Maternal folic acid supplementation during pregnancy is associated with improved cognitive performances in offspring. However, the effect of supplementation on offspring’s neurogenesis and synaptogenesis is unknown, and whether supplementation should be continued throughout pregnancy is controversial. In present study, 3 groups of female rats were fed a folate-normal diet, folate-deficient diet, or folate-supplemented diet from 1 week before mating until the end of pregnancy. A fourth group fed folate-normal diet from 1 week before mating until mating, then fed folate-supplemented diet for 10 consecutive days, then fed folate-normal diet until the end of pregnancy. Offspring were sacrificed on postnatal day 0 for measurement of neurogenesis and synaptogenesis by immunofluorescence and western blot. Additionally neural stem cells (NSCs) were cultured from offspring’s hippocampus for immunocytochemical measurement of their rates of proliferation and neuronal differentiation. The results demonstrated that maternal folic acid supplementation stimulated hippocampal neurogenesis by increasing proliferation and neuronal differentiation of NSCs, and also enhanced synaptogenesis in cerebral cortex of neonatal offspring. Hippocampal neurogenesis was stimulated more when supplementation was continued throughout pregnancy instead of being limited to the periconceptional period. In conclusion, maternal folic acid supplementation, especially if continued throughout pregnancy, improves neurogenesis and synaptogenesis in neonatal offspring.
Measuring and understanding individual differences in cognition
Authors: Boogert Neeltje J. , Madden Joah R. , Morand-Ferron Julie , Thornton Alex
Published: August 2018

Individuals vary in their cognitive performance. While this variation forms the foundation of the study of human psychometrics, its broader importance is only recently being recognized. Explicitly acknowledging this individual variation found in both humans and non-human animals provides a novel opportunity to understand the mechanisms, development and evolution of cognition. The papers in this special issue highlight the growing emphasis on individual cognitive differences from fields as diverse as neurobiology, experimental psychology and evolutionary biology. Here, we synthesize this body of work. We consider the distinct challenges in quantifying individual differences in cognition and provide concrete methodological recommendations. In particular, future studies would benefit from using multiple task variants to ensure they target specific, clearly defined cognitive traits and from conducting repeated testing to assess individual consistency. We then consider how neural, genetic, developmental and behavioural factors may generate individual differences in cognition. Finally, we discuss the potential fitness consequences of individual cognitive variation and place these into an evolutionary framework with testable hypotheses. We intend for this special issue to stimulate researchers to position individual variation at the centre of the cognitive sciences.

This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.
Linking personality and cognition: a meta-analysis
Authors: Dougherty Liam R. , Guillette Lauren M.
Published: August 2018

In the past decade, several conceptual papers have linked variation in animal personality to variation in cognition, and recent years have seen a flood of empirical studies testing this link. However, these results have not been synthesized in a quantitative way. Here, we systematically search the literature and conduct a phylogenetically controlled meta-analysis of empirical papers that have tested the relationship between animal personality (exploration, boldness, activity, aggression and sociability) and cognition (initial learning/reversal speed, number of correct choices/errors after standard training). We find evidence for a small but significant relationship between variation in personality and variation in learning across species in the absolute scale; however, thedirectionof this relationship is highly variable and when both positive and negative effect sizes are considered, the average effect size does not differ significantly from zero. Importantly, this variation among studies is not explained by differences in personality or learning measure, or taxonomic grouping. Further, these results do not support current hypotheses suggesting that that fast-explorers are fast-learners or that slow-explorers perform better on tests of reversal learning. Rather, we find evidence that bold animals are faster learners, but only when boldness is measured in response to a predator (or simulated predator) and not when boldness is measured by exposure to a novel object (or novel food). Further, although only a small sub-sample of papers reported results separately for males and females, sex explained a significant amount of variation in effect size. These results, therefore, suggest that, while personality and learning are indeed related across a range of species, the direction of this relationship is highly variable. Thus further empirical work is needed to determine whether there are important moderators of this relationship.

This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.
Comparative psychometrics: establishing what differs is central to understanding what evolves
Authors: Völter Christoph J. , Tinklenberg Brandon , Call Josep , Seed Amanda M.
Published: August 2018

Cognitive abilities cannot be measured directly. What we can measure is individual variation in task performance. In this paper, we first make the case for why we should be interested in mapping individual differences in task performance onto particular cognitive abilities: we suggest that it is crucial for examining the causes and consequences of variation both within and between species. As a case study, we examine whether multiple measures of inhibitory control for non-human animals do indeed produce correlated task performance; however, no clear pattern emerges that would support the notion of a common cognitive ability underpinning individual differences in performance. We advocate a psychometric approach involving a three-step programme to make theoretical and empirical progress: first, we need tasks that reveal signature limits in performance. Second, we need to assess the reliability of individual differences in task performance. Third, multi-trait multi-method test batteries will be instrumental in validating cognitive abilities. Together, these steps will help us to establish what varies between individuals that could impact their fitness and ultimately shape the course of the evolution of animal minds. Finally, we propose executive functions, including working memory, inhibitory control and attentional shifting, as a sensible starting point for this endeavour.

This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.
Stress hormones, social associations and song learning in zebra finches
Authors: Boogert Neeltje J. , Lachlan Robert F. , Spencer Karen A. , Templeton Christopher N. , Farine Damien R.
Published: August 2018

The use of information provided by others is a common short-cut adopted to inform decision-making. However, instead of indiscriminately copying others, animals are often selective in what, when and whom they copy. How do they decide which ‘social learning strategy’ to use? Previous research indicates that stress hormone exposure in early life may be important: while juvenile zebra finches copied their parents' behaviour when solving novel foraging tasks, those exposed to elevated levels of corticosterone (CORT) during development copied only unrelated adults. Here, we tested whether this switch in social learning strategy generalizes to vocal learning. In zebra finches, juvenile males often copy their father's song; would CORT-treated juveniles in free-flying aviaries switch to copying songs of other males? We found that CORT-treated juveniles copied their father's song less accurately as compared to control juveniles. We hypothesized that this could be due to having weaker social foraging associations with their fathers, and found that sons that spent less time foraging with their fathers produced less similar songs. Our findings are in line with a novel hypothesis linking early-life stress and social learning: early-life CORT exposure may affect social learning indirectly as a result of the way it shapes social affiliations.

This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.
A Chemically-triggered Transition from Conflict to Cooperation in Burying Beetles
Authors: Chen Bo-Fei , Liu Mark , Rubenstein Dustin R. , Sun Syuan-Jyun , Liu Jian-Nan , Lin Yu-Heng , Shen Sheng-Feng
Published: August 2018

Although interspecific competition has long been recognized as a major driver of trait divergence and adaptive evolution1–3, relatively little effort has focused on how it influences the evolution of intraspecific cooperation4–6. Here we identify the mechanism by which the perceived pressure of interspecific competition influences the transition from intraspecific conflict to cooperation in a facultative cooperatively breeding species, the Asian burying beetle Nicrophorus nepalensis. In their natural environment in central Taiwan, N. nepalensis are typically aggressive to conspecifics and only cooperate with others of their own species at critical carcass resources in the presence of blowflies, their primary competitors7. We demonstrate that beetles form larger groups and are more cooperative in carcass preparation in warmer environments where the pressure of interspecific competition with blowflies is highest8. To test the hypothesis that the presence of blowflies promotes beetle cooperation and to identify the mechanism by which this occurs, we manipulated blowfly larvae on carcasses in the lab. We not only found that beetles are more cooperative at carcasses when blowfly maggots have begun to digest the tissue, but that this social cooperation appears to be triggered by a single chemical cue— dimethyl disulfide (DMDS)—emitted from carcasses consumed by blowflies but not from control carcasses lacking blowflies. Our results provide experimental evidence that interspecific competition promotes the transition from intraspecific conflict to cooperation in N. nepalensis via a surprisingly simple social chemical cue that is a reliable indicator of interspecific competition. This finding helps bridge the gap between the proximate and ultimate factors regulating the transition between cooperation and conflict and moves toward a more comprehensive understanding of the evolution of mechanisms governing intraspecific variation in social behaviour.
Identification and Ranking of Recurrent Neo-Epitopes in Cancer
Authors: Blanc Eric , Holtgrewe Manuel , Dhamodaran Arunraj , Messerschmidt Clemens , Willimsky Gerald , Blankenstein Thomas , Beule Dieter
Published: August 2018

Immune escape is one of the hallmarks of cancer and several new treatment approaches attempt to modulate and restore the immune system’s capability to target cancer cells. At the heart of the immune recognition process lies antigen presentation from somatic mutations. These neo-epitopes are emerging as attractive targets for cancer immunotherapy and new strategies for rapid identification of relevant candidates have become a priority. We carefully screen TCGA data sets for recurrent somatic amino acid exchanges and apply MHC class I binding predictions. We propose a method for in silico selection and prioritization of candidates which have a high potential for neo-antigen generation and are likely to appear in multiple patients. While the percentage of patients carrying a specific neo-epitope and HLA-type combination is relatively small, the sheer number of new patients leads to surprisingly high reoccurence numbers. We identify 769 epitopes which are expected to occur in 77629 patients per year. While our candidate list will definitely contain false positives, the results provide an objective order for wet-lab testing of reusable neo-epitopes. Thus recurrent neo-epitopes may be suitable to supplement existing personalized T cell treatment approaches with precision treatment options.
Meiotic drive of female-inherited supernumerary chromosomes in a pathogenic fungus
Authors: Habig Michael , Kema Gert H.J. , Stukenbrock Eva H.
Published: August 2018

Meiosis is a key cellular process of sexual reproduction involving the pairing of homologous sequences. In many species however, meiosis can also involve the segregation of supernumerary chromosomes, which can lack a homolog. How these unpaired chromosomes undergo meiosis is largely unknown. In this study we investigated chromosome segregation during meiosis in the haploid fungusZymoseptoria triticithat possesses a large complement of supernumerary chromosomes. We used isogenic whole chromosome deletion strains to compare meiotic transmission of chromosomes when paired and unpaired. Unpaired chromosomes inherited from the male parent as well as paired supernumerary chromosomes showed Mendelian inheritance. In contrast, unpaired chromosomes inherited from the female parent showed non-Mendelian inheritance but were amplified and transmitted to all meiotic products. We concluded that the supernumerary chromosomes ofZ. triticishow a meiotic drive and propose an additional feedback mechanism during meiosis which initiates amplification of unpaired female-inherited chromosomes.
No single, stable 3D representation can explain pointing biases in a spatial updating task
Authors: Vuong Jenny , Fitzgibbon Andrew W. , Glennerster Andrew
Published: August 2018

People are able to keep track of objects as they navigate through space, even when objects are out of sight. This requires some kind of representation of the scene and of the observer’s location but the form this representation might take is debated. We tested the accuracy and reliability of observers’ estimates of the visual direction of previously-viewed targets. Participants viewed 4 objects from one location, with binocular vision and small head movements giving information about the 3D locations of the objects. Without any further sight of the targets, participants walked to another location and pointed towards them. All the conditions were tested in an immersive virtual environment and some were also carried out in a real scene. Participants made large, consistent pointing errors that are poorly explained by any consistent 3D representation. Instead, if a 3D representation is to account for the data it would need to be one where the target boxes were squashed, almost into a plane, quite far away from the true location of the boxes and in different places depending on the orientation of the obscuring wall at the moment the participant points. In short, our data show that the mechanisms for updating visual direction of unseen targets are not based on a stable 3D model of the scene, even a distorted one.
A Framework for Cortical Layer Composition Analysis using Low Resolution T1 MRI Images (August 2018)
Authors: Shamir Ittai , Tomer Omri , Baratz Zvi , Tsarfaty Galia , Faraggi Maya , Horowitz Assaf , Assaf Yaniv
Published: August 2018

The layer composition of the cerebral cortex represents a unique anatomical fingerprint of brain development, function, connectivity and pathology. Historically the cortical layers were investigated solely ex-vivo using histological means, but recent magnetic resonance imaging (MRI) studies suggest that T1 relaxation images can be utilized to separate the layers. Despite technological advancements in the field of high resolution MRI, accurate estimation of whole brain layer composition has remained limited due to partial volume effects, leaving some layers far beyond the image resolution. In this study we offer a simple and accurate method for layer composition analysis, resolving partial volume effects and cortical curvature heterogeneity. We use a low resolution echo planar imaging inversion recovery (EPI IR) MRI scan protocol that provides fast acquisition (~12 minutes) and enables extraction of multiple T1 relaxation time components per voxel, which are assigned to types of brain tissue and utilized to extract the subvoxel composition of each T1 layer. While previous investigation of the layers required the estimation of cortical normals or smoothing of layer widths (similar to VBM), here we developed a sphere-based approach to explore the inner mesoscale architecture of the cortex. Our novel algorithm conducts spatial analysis using volumetric sampling of a system of virtual spheres dispersed throughout the entire cortical space. The methodology offers a robust and powerful framework for quantification and visualization of the layers on the cortical surface, providing a basis for quantitative investigation of their role in cognition, physiology and pathology.
A national ‘safe and just operating space’ for all in India: Past, Present and Futurea
Authors: Roy Ajishnu , Pramanick Kousik
Published: August 2018

With 1.3 billion populaces on the commencement of the 21stcentury, India is currently impending towards upholding a subtle equilibrium between persisting social development and well-being without depleting existing biophysical resources at the national level or surpassing global average per capita obtainability. In this paper, we have structured a top-down per capita framework to explore national ‘safe and just operating space’ (NSJOS) to apprehend not only past fluctuations that bring about the present conditions but also the plausible future consequences, with India as a case study. Coalescing 27 indicators, all pertaining to Sustainable Development Goals (except – SDG 17), accompanied by their corresponding environmental boundaries or preferred social thresholds, present study probes into both biophysical (for environmental stress) and social development (for social deficit) attributes of India. This analysis shows India has already crossed three of seven dimensions of biophysical boundaries (freshwater, nitrogen and phosphorus use). Also, at the existing rate, India is going to cross the remainder of the boundaries within 2045-2050 (climate change, arable land use, ecological and material footprint). Of 20 indicators used for social development, only five have already or will meet corresponding desired thresholds of United Nations Sustainable Development Goals 2015. Using tendencies of past variations, the results indicate that if lowest per capita consumption can be attained and uphold, even with projected population growth, total consumption of four biophysical resources (climate change, nitrogen use, ecological and material footprint) can be slashed from today’s level in 2050. Adaptations in national policy are indispensable if India wants to accomplish sufficiency in biophysical resources whilst bestowing social equity in access and exploitation of those resources towards the continuance of social developments in forthcoming times.
Reversible inactivation of different millimeter-scale regions of primate IT results in different patterns of core object recognition deficits
Authors: Rajalingham Rishi , DiCarlo James J.
Published: August 2018

Extensive research suggests that the inferior temporal (IT) population supports visual object recognition behavior. However, causal evidence for this hypothesis has been equivocal, particularly beyond the specific case of face-selective sub-regions of IT. Here, we directly tested this hypothesis by pharmacologically inactivating individual, millimeter-scale sub-regions of IT while monkeys performed several object discrimination tasks, interleaved trial-by-trial. First, we observed that IT inactivation resulted in reliable contralateral-biased task-selective behavioral deficits. Moreover, inactivating different IT sub-regions resulted in different patterns of task deficits, each predicted by that sub-region’s neuronal object discriminability. Finally, the similarity between different inactivation effects was tightly related to the anatomical distance between corresponding inactivation sites. Taken together, these results provide direct evidence that IT cortex causally supports general core object recognition, and that the underlying IT codes are topographically organized.
Experimental study of Young modulus of Attacus atlas, Vespa crabro, and Libellula depressa wings
Authors: Landowski Michal , Kunicka-Kowalska Zuzanna , Sibilski Krzysztof
Published: August 2018

This paper describes a scientific research aimed at obtaining data for determining Young modulus of the wings of selected insects’ species. A small testing machine intended for three-point bending and equipped with instruments registering low forces was constructed for the needs of the experiment. The machine was used to perform numerous bending tests of wings of three species of insects (obtained from a breeding farm): Attacus atlas, Vespa crabro, Libellula depressa in various air-humidity conditions. Values of the force and displacement obtained in the course of the tests were used to calculate Young modulus. In order to do so, it was also necessary to obtain the moment of inertia of the wing cross-section. These values were measured on the basis of the images obtained with a SEM microscope. Obtained results were averaged and presented with a breakdown by air-humidity conditions. It was observed that Young modulus decreased with an increase of humidity; hence the calculations of the percentage decrease of this mechanical parameter were performed. Obtained results were compared with the observed structure which was also presented under light microscope. It transpired that the construction of a wing does not only influence the mechanical values but also it influences their susceptibility to the changes occurring in the environment. Thereby, differences between Lepidoptera and Hymenoptera insects were indicated also within the aspect discussed in this paper.