bluuebunny/crossref_metadata_2025 huggingface dataset:
Usefulness of Virtual Monochromatic Dual-Layer Computed Tomographic Imaging for Breast Carcinoma
Authors: Inoue Taihei , Nakaura Takeshi , Iyama Ayumi , Kidoh Masafumi , Nagayama Yasunori , Uetani Hiroyuki , Oda Seitaro , Utsunomiya Daisuke , Yamashita Yasuyuki
Published: January 2020

Objective

This study aimed to evaluate virtual monochromatic images (VMIs) obtained using dual-layer dual-energy computed tomography (CT) for breast carcinoma.

Methods

We retrospectively enrolled 28 patients with breast cancer who were pathologically diagnosed using dual-layer dual-energy CT. Virtual monochromatic images (40–200 keV) were generated. We compared CT number, image noise, contrast, and contrast-to-noise ratio (CNR) between VMIs with the highest CNR and conventional CT images. We performed qualitative image analysis between VMIs at optimized energy and conventional CT images.

Results

Image noise of VMIs was not significantly different from that of the conventional CT images. As the x-ray energy decreased, CNR increased. The 40-keV VMIs were highest CNR and higher than that of the conventional CT images. In qualitative image analysis, the 40-keV images were significantly higher than conventional CT images.

Conclusion

Both qualitative and quantitative analyses showed that the image quality of VMIs at 40 keV was significantly higher than that of conventional CT images.
Role of Diffusional Kurtosis Imaging in Differentiating Neuromyelitis Optica–Related and Multiple Sclerosis–Related Acute Optic Neuritis: Comparison With Diffusion-Weighted Imaging
Authors: Lu Ping , Yuan Ting , Liu Xilan , Tian Guohong , Zhang Jibin , Sha Yan
Published: January 2020

Purpose

The discrimination between neuromyelitis optica (NMO)– and multiple sclerosis (MS)–related acute optic neuritis (ON) after the first presentation is difficult in clinical practice. Through a comparison with diffusion-weighted imaging using readout-segmented echo-planar imaging (RESOLVE-DWI), our aim was to determine the feasibility of diffusional kurtosis imaging (DKI) for differential diagnosis.

Materials and Methods

Orbital DKI and RESOLVE-DWI in a 3.0-T scanner were performed on 37 patients with acute ON (15 NMO-related and 22 MS-related). The mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), mean diffusivity (MD), and apparent diffusion coefficient (ADC) were calculated for quantitative analyses, and receiver operating characteristic curve analyses were also performed to determine their abilities to differentiate the 2 conditions.

Results

The intraclass correlation coefficients among observers were 0.842, 0.885, 0.828, 0.871, and 0.942 for MK, RK, AK, MD, and ADC, respectively, in the affected nerve group and 0.890, 0.840, 0.832, 0.934, and 0.941 in the unaffected nerve group. Regarding the comparisons of the DKI and RESOLVE-DWI parameters among the groups, the mean MK, RK, AK, MD, and ADC values were significantly lower in the affected groups (all, P < 0.001). Furthermore, the MK, RK, MD, and ADC values were significantly lower in the NMO-ON group than in the MS-ON group (P = 0.001, 0.002, 0.013, and <0.001, respectively), and no significant differences were found in the AK values (P = 0.064). In addition, establishing MK ≤ 0.843 as the diagnostic criterion for NMO-related acute ON provided the highest sensitivity (90.5%), whereas the highest specificity (91.3%) was obtained using RK ≤ 0.784 as the diagnostic criterion.

Conclusions

Diffusional kurtosis imaging is helpful for differentiating NMO-related acute ON from MS-related acute ON, and it can achieve more agreeable sensitivity and specificity than RESOLVE-DWI in differential diagnosis.
Effectiveness of Preoperative Iron Supplementation in Major Surgical Patients With Iron Deficiency
Authors: Triphaus Chris , Judd Leonie , Glaser Patricia , Goehring Marie H. , Schmitt Elke , Westphal Sabine , Füllenbach Christoph , Lindau Simone , Zacharowski Kai , Meybohm Patrick , Choorapoikayil Suma
Published: January 2020

Objective:

To evaluate the effectiveness of routine intravenous iron in surgical patients with iron deficiency anemia (IDA).

Background:

Anemia is the most common medical disease in the world and is an independent risk factor for morbidity and mortality. Iron deficiency (ID) is the main cause for anemia and constitutes a potentially preventable condition with great impact on surgical outcome.

Methods:

In this prospective single-center observational study, surgical patients were screened for the presence of anemia and ID. Patients were assigned to 1 of 4 study groups: A−(no anemia); A−, ID+, T+(no anemia, iron-deficient, iron supplementation); A+(anemia); and A+, ID+, T+(anemia, iron-deficient, iron supplementation) according to hemoglobin level, iron status, and supplementation with iron.

Results:

Among 1728 patients, 1028 were assigned to A−; 55 to A−, ID+, T+; 461 to A+; and 184 to A+, ID+, T+. While all iron-supplemented IDA patients required less red blood cell (RBC) transfusion during the postoperative period (A+42.5% vs A+, ID+, T+31.5%), a reduced intraoperative transfusion rate was observed for ID and IDA patients only if iron was supplemented >7 days before surgery. Hospital stay was significantly reduced by 2.8 days in iron-supplemented patients (P< 0.01 comparing 13.9 ± 0.8 days for A+, ID+, T+vs. 16.7 ± 0.7 days for A+).

Conclusion:

Preoperative IDA management with intravenous iron is effective in improving hemoglobin level, thereby reducing intraoperative RBC transfusion rate particular if iron is administrated >7 days before surgery. Hospital length of stay was reduced in all preoperatively iron-supplemented IDA patients.
Anellovirus Dynamics Are Associated With Primary Graft Dysfunction in Lung Transplantation
Authors: Blatter Joshua A. , Takahashi Tsuyoshi , Mittler Brigitte , Nava Ruben G. , Puri Varun , Kreisel Daniel , Wang David
Published: January 2020

Background.

Primary graft dysfunction (PGD) is the leading cause of early death in lung transplant. Anelloviruses are small circular DNA viruses that have been noted to be present at elevated levels in immunosuppressed patients. They have been associated with both short- and long-term outcomes in lung transplant, and we hypothesized that anellovirus dynamics might be associated with the development of PGD.

Methods.

We analyzed alphatorquevirus (ie, an anellovirus genus) levels in whole blood samples from 64 adult lung transplant recipients.

Results.

Patients with a relatively rapid rise in alphatorquevirus levels in the week following transplant were less likely to develop higher-grade PGD over the first 3 days following transplant (P = 0.031).

Conclusions.

This study is the first to establish an association between the development of PGD and a component of the blood virome. While it is not known whether anelloviruses directly affect outcomes in lung transplant, they may serve as a biomarker of immune status in lung transplant recipients.
Increased summer food supply decreases non-breeding movement in black-legged kittiwakes
Authors: Whelan Shannon , Hatch Scott A. , Irons David B. , McKnight Alyson , Elliott Kyle H.
Published: January 2020

Individual condition at one stage of the annual cycle is expected to influence behaviour during subsequent stages, yet experimental evidence of food-mediated carry-over effects is scarce. We used a food supplementation experiment to test the effects of food supply during the breeding season on migration phenology and non-breeding behaviour. We provided an unlimited supply of fish to black-legged kittiwakes (
Rissa tridactyla
) during their breeding season on Middleton Island, Alaska, monitored reproductive phenology and breeding success, and used light-level geolocation to observe non-breeding behaviour. Among successful breeders, fed kittiwakes departed the colony earlier than unfed controls. Fed kittiwakes travelled less than controls during the breeding season, contracting their non-breeding range. Our results demonstrate that food supply during the breeding season affects non-breeding phenology, movement and distribution, providing a potential behavioural mechanism underlying observed survival costs of reproduction.
When do older birds better resist stress? A study of the corticosterone stress response in snow petrels
Authors: Angelier Frédéric , Chastel Olivier , Lendvai Adam Z. , Parenteau Charline , Weimerskirch Henri , Wingfield John C.
Published: January 2020

Life-history theory predicts that, to optimize their fitness, individuals should increase their reproductive effort as their residual reproductive value decreases. Accordingly, several studies have shown that individuals downregulate their glucocorticoid stress response (a proxy of reproductive investment in vertebrates) as they age, and as the subsequent reproductive value decreases. However, and surprisingly, results appear inconsistent, suggesting that the environmental context or the individual state may affect the relationship between age and reproductive effort. Here, we tested for the first time this hypothesis, and more specifically, whether this attenuation of the corticosterone stress response with advancing age depends on the energetic status of individuals. We compared the influence of age on the corticosterone stress response between fasting and non-fasting breeding snow petrels (
Pagodroma nivea
), an extremely long-lived bird. As expected, we found that the corticosterone stress response was attenuated in old petrels, but only when they were not fasting. Interestingly, this pattern was not apparent in fasting petrels, suggesting that old birds downregulate their corticosterone stress response and increase their parental investment only when they are in good body condition. At the ultimate level, old individuals may maintain a strong corticosterone stress response when fasting because the survival costs of increased stress resistance and parental effort might then outweigh their reproductive benefits.
Knowing when to stick: touch receptors found in the remora adhesive disc
Authors: Cohen Karly E. , Flammang Brooke E. , Crawford Callie H. , Hernandez L. Patricia
Published: January 2020

Remoras are fishes that piggyback onto larger marine fauna via an adhesive disc to increase locomotor efficiency, likelihood of finding mates and access to prey. Attaching rapidly to a large, fast-moving host is no easy task, and while research to date has focused on how the disc supports adhesion, no attention has been paid to how or if remoras are able to sense attachment. We identified push-rod-like mechanoreceptor complexes embedded in the soft lip of the remora adhesive disc that are known in other organisms to respond to touch and shear forces. This is, to our knowledge, the first time such mechanoreceptor complexes are described in fishes as they were only known previously in monotremes. The presence of push-rod-like mechanoreceptor complexes suggests not only that fishes may be able to sense their environment in ways not heretofore described but that specialized tactile mechanoreceptor complexes may be a more basal vertebrate feature than previously thought.
Influence of the slight adjustment of oxides on the structural and physico-chemical properties of thin film transistor-liquid crystal display substrate glass
Authors: Cui Jiedong , Cao Xin , Shi Lifen , Zhong Zhaojin , Wang Pingping , Ma Liyun
Published: January 2020

By the slight adjustment of oxides constituting thin film transistor-liquid crystal display (TFT-LCD) substrate glass, including equal mole fraction substitution of Al
2
O
3
, GeO
2
, B
2
O
3
, P
2
O
5
and ZrO
2
for SiO
2
, as well as the substitution of CaO for SrO with the total contents unchanged, the structural and physico-chemical properties of the glass was investigated by Raman spectroscopy and other measurements. The results showed that the short-range disorder brought by the substitution of GeO
2
, B
2
O
3
and P
2
O
5
for SiO
2
could weaken the stability and compactness of the glass network, and the physico-chemical properties deteriorated, while the process of glass melting would become easier accordingly. The short-range disorder by the substitution of ZrO
2
for SiO
2
with 1% mole fraction showed a little difference with other samples. Finally, the substitution of modified cations, such as CaO and SrO, showed a smaller variation compared with the substitution of network formers. On the condition of 1% mole fraction substitution of oxides investigated, the variation of samples showed a reasonable change and the performance was basically all satisfied for the use of TFT-LCD substrate.
What makes a pair bond in a Neotropical primate: female and male contributions
Authors: Dolotovskaya Sofya , Walker Sarah , Heymann Eckhard W.
Published: January 2020

Pair living and pair bonding are rare in mammals, and the mechanisms of their maintenance remain a puzzle. Titi monkeys, a ‘textbook example’ for ‘monogamous’ primates, have strong pair bonds and extensive male care. To investigate mechanisms of pair-bond maintenance, we studied seven wild groups of red titis (Plecturocebus cupreus) in Peruvian Amazonia over a period of 14 months. We analysed pair bonds by measuring proximity, grooming and approaches/leaves within pairs, and collected data on intergroup encounters. Females contributed to grooming more than males, especially during infant dependency, when most of the grooming within pairs was done by females. Females were also more active in controlling proximity between pair mates, making most of the approaches and leaves. Males, on the other hand, invested more in territorial defences. They participated in more intergroup encounters than females and were more active during these encounters. Our data is most consistent with the ‘male-services’ hypothesis for pair-bond maintenance, where a female contributes more to the proximity and affiliation maintenance while a male provides beneficial services.
Quasi-Herglotz functions and convex optimization
Authors: Ivanenko Y. , Nedic M. , Gustafsson M. , Jonsson B. L. G. , Luger A. , Nordebo S.
Published: January 2020

We introduce the set of quasi-Herglotz functions and demonstrate that it has properties useful in the modelling of non-passive systems. The linear space of quasi-Herglotz functions constitutes a natural extension of the convex cone of Herglotz functions. It consists of differences of Herglotz functions and we show that several of the important properties and modelling perspectives are inherited by the new set of quasi-Herglotz functions. In particular, this applies to their integral representations, the associated integral identities or sum rules (with adequate additional assumptions), their boundary values on the real axis and the associated approximation theory. Numerical examples are included to demonstrate the modelling of a non-passive gain medium formulated as a convex optimization problem, where the generating measure is modelled by using a finite expansion of B-splines and point masses.
Optimization and blends study of heterogeneous acid catalyst-assisted esterification of palm oil industry by-product for biodiesel production
Authors: Akinfalabi Shehu-Ibrahim , Rashid Umer , Arbi Nehdi Imededdine , Yaw Choong Thomas Shean , Sbihi Hassen Mohamed , Gewik Mohamed Mossad
Published: January 2020

The optimum conditions to produce palm fatty acid distillate (PFAD)-derived-methyl esters via esterification have been demonstrated with the aid of the response surface methodology (RSM) with central composite rotatable design in the presence of heterogeneous acid catalyst. The effect of four reaction variables, reaction time (30–110 min), reaction temperature (30–70°C), catalyst concentration (1–3 wt.%) and methanol : PFAD molar ratio (3 : 1–11 : 1), were investigated. The reaction time had the most influence on the yield response, while the interaction between the reaction time and the catalyst concentration, with an
F
-value of 95.61, contributed the most to the esterification reaction. The model had an
R
2
-value of 0.9855, suggesting a fit model, which gave a maximum yield of 95%. The fuel properties of produced PFAD methyl ester were appraised based on the acid value, iodine value, cloud and pour points, flash point, kinematic viscosity, density, ash and water contents and were compared with biodiesel EN 14214 and ASTM D-6751 standard limits. The PFAD methyl ester was further blended with petro-diesel from B0, B3, B5, B10, B20 and B100, on a volumetric basis. The blends were characterized by TGA, DTG and FTIR. With an acid value of 0.42 (mg KOH g
−1
), iodine value of 63 (g.I
2
/100 g), kinematic viscosity of 4.31 (mm
2
s
−1
), the PFAD methyl ester has shown good fuel potential, as all of its fuel properties were within the permissible international standards for biodiesel.
Spatial heterogeneity of the shorebird gastrointestinal microbiome
Authors: Grond Kirsten , Guilani Hannah , Hird Sarah M.
Published: January 2020

The gastrointestinal tract (GIT) consists of connected structures that vary in function and physiology, and different GIT sections potentially provide different habitats for microorganisms. Birds possess unique GIT structures, including the oesophagus, proventriculus, gizzard, small intestine, caeca and large intestine. To understand birds as hosts of microbial ecosystems, we characterized the microbial communities in six sections of the GIT of two shorebird species, the Dunlin and Semipalmated Sandpiper, identified potential host species effects on the GIT microbiome and used microbial source tracking to determine microbial origin throughout the GIT. The upper three GIT sections had higher alpha diversity and genus richness compared to the lower sections, and microbial communities in the upper GIT showed no clustering. The proventriculus and gizzard microbiomes primarily originated from upstream sections, while the majority of the large intestine microbiome originated from the caeca. The heterogeneity of the GIT sections shown in our study urges caution in equating data from faeces or a single GIT component to the entire GIT microbiome but confirms that ecologically similar species may share many attributes in GIT microbiomes.
Local and global perspectives on diffusion maps in the analysis of molecular systems
Authors: Trstanova Z. , Leimkuhler B. , Lelièvre T.
Published: January 2020

Diffusion maps approximate the generator of Langevin dynamics from simulation data. They afford a means of identifying the slowly evolving principal modes of high-dimensional molecular systems. When combined with a biasing mechanism, diffusion maps can accelerate the sampling of the stationary Boltzmann–Gibbs distribution. In this work, we contrast the local and global perspectives on diffusion maps, based on whether or not the data distribution has been fully explored. In the global setting, we use diffusion maps to identify metastable sets and to approximate the corresponding committor functions of transitions between them. We also discuss the use of diffusion mapswithinthe metastable sets, formalizing the locality via the concept of the quasi-stationary distribution and justifying the convergence of diffusion maps within a local equilibrium. This perspective allows us to propose an enhanced sampling algorithm. We demonstrate the practical relevance of these approaches both for simple models and for molecular dynamics problems (alanine dipeptide and deca-alanine).
Gadfly petrels use knowledge of the windscape, not memorized foraging patches, to optimize foraging trips on ocean-wide scales
Authors: Ventura Francesco , Granadeiro José Pedro , Padget Oliver , Catry Paulo
Published: January 2020

Seabirds must often travel vast distances to exploit heterogeneously distributed oceanic resources, but how routes and destinations of foraging trips are optimized remains poorly understood. Among the seabirds, gadfly petrels (
Pterodroma
spp.) are supremely adapted for making efficient use of wind energy in dynamic soaring flight. We used GPS tracking data to investigate the role of wind in the flight behaviour and foraging strategy of the Desertas petrel,
Pterodroma deserta
. We found that rather than visiting foraging hotspots, Desertas petrels maximize prey encounter by covering some of the longest distances known in any animal in a single foraging trip (up to 12 000 km) over deep, pelagic waters. Petrels flew with consistent crosswind (relative wind angle 60°), close to that which maximizes their groundspeed. By combining state–space modelling with a series of comparisons to simulated foraging trips (reshuffled-random, rotated, time-shifted, reversed), we show that this resulted in trajectories that were close to the fastest possible, given the location and time. This wind use is thus consistent both with birds using current winds to fine-tune their routes and, impressively, with an
a priori
knowledge of predictable regional-scale wind regimes, facilitating efficient flight over great distances before returning to the home colony.
Linking hunting weaponry to attack strategies in sailfish and striped marlin
Authors: Hansen M. J. , Krause S. , Breuker M. , Kurvers R. H. J. M. , Dhellemmes F. , Viblanc P. E. , Müller J. , Mahlow C. , Boswell K. , Marras S. , Domenici P. , Wilson A. D. M. , Herbert-Read J. E. , Steffensen J. F. , Fritsch G. , Hildebrandt T. B. , Zaslansky P. , Bach P. , Sabarros P. S. , Krause J.
Published: January 2020

Linking morphological differences in foraging adaptations to prey choice and feeding strategies has provided major evolutionary insights across taxa. Here, we combine behavioural and morphological approaches to explore and compare the role of the rostrum (bill) and micro-teeth in the feeding behaviour of sailfish (
Istiophorus platypterus
) and striped marlin (
Kajikia audax
) when attacking schooling sardine prey. Behavioural results from high-speed videos showed that sailfish and striped marlin both regularly made rostrum contact with prey but displayed distinct strategies. Marlin used high-speed dashes, breaking schools apart, often contacting prey incidentally or tapping at isolated prey with their rostra; while sailfish used their rostra more frequently and tended to use a slower, less disruptive approach with more horizontal rostral slashes on cohesive prey schools. Capture success per attack was similar between species, but striped marlin had higher capture rates per minute. The rostra of both species are covered with micro-teeth, and micro-CT imaging showed that species did not differ in average micro-tooth length, but sailfish had a higher density of micro-teeth on the dorsal and ventral sides of their rostra and a higher amount of micro-teeth regrowth, suggesting a greater amount of rostrum use is associated with more investment in micro-teeth. Our analysis shows that the rostra of billfish are used in distinct ways and we discuss our results in the broader context of relationships between morphological and behavioural feeding adaptations across species.
A series of unfortunate events: characterizing the contingent nature of physiological extremes using long-term environmental records
Authors: Dowd W. Wesley , Denny Mark W.
Published: January 2020

Accelerating shifts in global climate have focused the attention of ecologists and physiologists on extreme environmental events. However, the dynamic process of physiological acclimatization complicates study of these events' consequences. Depending on the range of plasticity and the amplitude and speed of environmental variation, physiology can be either in tune with the surroundings or dangerously out of synch. We implement a modified quantitative approach to identifying extreme events in environmental records, proposing that organisms are stressed by deviations of the environment from the current level of acclimatization, rather than by the environment's absolute state. This approach facilitates an unambiguous null model for the consequences of environmental variation, identifying a unique subset of events as ‘extremes’. Specifically, it allows one to examine how both the temporal extent (the acclimatization window) and type of an environmental signal affect the magnitude and timing of extreme environmental events. For example, if physiology responds to the moving average of past conditions, a longer acclimatization window generally results in greater imposed stress. If instead physiology responds to historical maxima, longer acclimatization windows reduce imposed stress, albeit perhaps at greater constitutive cost. This approach should be further informed and tested with empirical experiments addressing the history-dependent nature of acclimatization.
A comparison of eDNA to camera trapping for assessment of terrestrial mammal diversity
Authors: Leempoel Kevin , Hebert Trevor , Hadly Elizabeth A.
Published: January 2020

Before environmental DNA (eDNA) can establish itself as a robust tool for biodiversity monitoring, comparison with existing approaches is necessary, yet is lacking for terrestrial mammals. Moreover, much is unknown regarding the nature, spread and persistence of DNA shed by animals into terrestrial environments, or the optimal experimental design for understanding these potential biases. To address some of these challenges, we compared the detection of terrestrial mammals using eDNA analysis of soil samples against confirmed species observations from a long-term (approx. 9-year) camera-trapping study. At the same time, we considered multiple experimental parameters, including two sampling designs, two DNA extraction kits and two metabarcodes of different sizes. All mammals regularly recorded with cameras were detected in eDNA. In addition, eDNA reported many unrecorded small mammals whose presence in the study area is otherwise documented. A long metabarcode (≈220 bp) offering a high taxonomic resolution, achieved a similar efficiency as a shorter one (≈70 bp) and a phosphate buffer-based extraction gave similar results as a total DNA extraction method, for a fraction of the price. Our results support that eDNA-based monitoring should become a valuable part of ecosystem surveys, yet mitochondrial reference databases need to be enriched first.
Rats play tit-for-tat instead of integrating social experience over multiple interactions
Authors: Schweinfurth Manon K. , Taborsky Michael
Published: January 2020

Theoretical models of cooperation typically assume that agents use simple rules based on last encounters, such as ‘tit-for-tat’, to reciprocate help. By contrast, empiricists generally suppose that animals integrate multiple experiences over longer timespans. Here, we compared these two alternative hypotheses by exposing Norway rats to partners that cooperated on three consecutive days but failed to cooperate on the fourth day, and to partners that did the exact opposite. In additional controls, focal rats experienced cooperating and defecting partners only once. In a bar-pulling setup, focal rats based their decision to provide partners with food on last encounters instead of overall cooperation levels. To check whether this might be owing to a lack of memory capacity, we tested whether rats remember the outcome of encounters that had happened three days before. Cooperation was not diminished by the intermediate time interval. We conclude that rats reciprocate help mainly based on most recent encounters instead of integrating social experience over longer timespans.
In the corner of the eye: camouflaging motion in the peripheral visual field
Authors: Smart Ioan E. , Cuthill Innes C. , Scott-Samuel Nicholas E.
Published: January 2020

Most animals need to move, and motion will generally break camouflage. In many instances, most of the visual field of a predator does not fall within a high-resolution area of the retina and so, when an undetected prey moves, that motion will often be in peripheral vision. We investigate how this can be exploited by prey, through different patterns of movement, to reduce the accuracy with which the predator can locate a cryptic prey item when it subsequently orients towards a target. The same logic applies for a prey species trying to localize a predatory threat. Using human participants as surrogate predators, tasked with localizing a target on peripherally viewed computer screens, we quantify the effects of movement (duration and speed) and target pattern. We show that, while motion is certainly detrimental to camouflage, should movement be necessary, some behaviours and surface patterns reduce that cost. Our data indicate that the phenotype that minimizes localization accuracy is unpatterned, having the mean luminance of the background, does not use a startle display prior to movement, and has short (below saccadic latency), fast movements.
Placental effects on the maternal brain revealed by disrupted placental gene expression in mouse hybrids
Authors: Arévalo Lena , Campbell Polly
Published: January 2020

The mammalian placenta is both the physical interface between mother and fetus, and the source of endocrine signals that target the maternal hypothalamus, priming females for parturition, lactation and motherhood. Despite the importance of this connection, the effects of altered placental signalling on the maternal brain are insufficiently studied. Here, we show that placental dysfunction alters gene expression in the maternal brain, with the potential to affect maternal behaviour. Using a cross between the house mouse and the Algerian mouse, in which hybrid placental development is abnormal, we sequenced late-gestation placental and maternal medial preoptic area transcriptomes and quantified differential expression and placenta-maternal brain co-expression between normal and hybrid pregnancies. The expression of
Fmn1
and
Drd3
was significantly altered in the brains of females exposed to hybrid placentas. Most strikingly, expression patterns of placenta-specific gene families and
Drd3
in the brains of house mouse females carrying hybrid litters matched those of female Algerian mice, the paternal species in the cross. Our results indicate that the paternally derived placental genome can influence the expression of maternal–fetal communication genes, including placental hormones, suggesting an effect of the offspring's father on the mother's brain.
The Camouflage Machine: Optimising protective colouration using deep learning with genetic algorithms
Authors: Fennell J. G. , Talas L. , Baddeley R. J. , Cuthill I. C. , Scott-Samuel N. E.
Published: January 2020

The essential problem in visual detection is separating an object from its background. Whether in nature or human conflict, camouflage aims to make the problem harder, while conspicuous signals (e.g. for warning or mate attraction) require the opposite. Our goal is to provide a reliable method for identifying the hardest and easiest to find patterns, for any given environment. The problem is challenging because the parameter space provided by varying natural scenes and potential patterns is vast. Here we successfully solve the problem using deep learning with genetic algorithms and illustrate our solution by identifying appropriate patterns in two environments. To show the generality of our approach, we do so for both trichromatic and dichromatic visual systems. Patterns were validated using human participants; those identified as the best camouflage were significantly harder to find than a widely adopted military camouflage pattern, while those identified as most conspicuous were significantly easier than other patterns. Our method, dubbed the ‘Camouflage Machine’, will be a useful tool for those interested in identifying the most effective patterns in a given context.
Different ecological processes drive the assembly of dominant and rare root-associated bacteria in a promiscuous legume
Authors: Ramoneda Josep , Le Roux Jaco , Frossard Emmanuel , Frey Beat , Gamper Hannes Andres
Published: January 2020

Understanding how plant-associated microbial communities assemble and the roles they play in plant performance are major goals in microbial ecology. For nitrogen-fixing rhizobia, assemblages are mostly determined by filtering by the host as well as abiotic soil conditions. However, for legumes adapted to highly variable environments and nutrient-poor soils, filtering out rhizobial partners may not be an effective strategy to ensure symbiotic benefits. As a consequence, this can lead to net increases in rhizobial diversity driven by stochastic (neutral) assembly processes. Here, we addressed whether symbiotic promiscuity of rooibos (Aspalathus linearisBurm. Dahlgren), reflects increases in rhizobial diversity that are independent of the environmental conditions, following a neutral assembly. We performed a common garden experiment to assess whether root system size and location- and habitat-specific rhizobial propagule pools of rooibos affected rhizobial community diversity and composition. We found a dominance of drift in driving taxonomic turnover in the root nodule communities, but operating at different scales in the dominantMesorhizobiumsymbionts and the rest of bacterial taxa. Specifically, drift triggered differentiation between the core rhizobial symbionts of rooibos due to dispersal limitation on a regional scale, whereas it dominated the assembly of non-dominant rhizobial taxa at the root level. This suggests the existence of a significant neutral component in rhizobial community assembly when selectivity by the host plant is low. We conclude that in this promiscuous legume neutral processes govern bacterial community root nodule community assembly, but that these operate at different scales in dominant and rare rhizobial symbionts of the plant.
Unsupervised changes in core object recognition behavior are predicted by neural plasticity in inferior temporal cortex
Authors: Jia Xiaoxuan , Hong Ha , DiCarlo James J.
Published: January 2020

Temporal continuity of object identity is a feature of natural visual input, and is potentially exploited -- in an unsupervised manner -- by the ventral visual stream to build the neural representation in inferior temporal (IT) cortex and IT-dependent core object recognition behavior. Here we investigated whether plasticity of individual IT neurons underlies human behavioral changes induced with unsupervised visual experience by building a single-neuron plasticity model combined with a previously established IT population-to-recognition-behavior linking model to predict human learning effects. We found that our model quite accurately predicted the mean direction, magnitude and time course of human performance changes. We also found a previously unreported dependency of the observed human performance change on the initial task difficulty. This result adds support to the hypothesis that tolerant core object recognition in human and non-human primates is instructed -- at least in part -- by naturally occurring unsupervised temporal contiguity experience.
Structure of the teneurin-latrophilin complex: Alternative splicing controls synapse specificity by a novel mechanism
Authors: Li Jingxian , Xie Yuan , Cornelius Shaleeka , Jiang Xian , Kordon Szymon P. , Sando Richard , Pan Man , Leon Katherine , Südhof Thomas C. , Zhao Minglei , Araç Demet
Published: January 2020

The trans-synaptic interaction of the cell-adhesion molecules teneurins (Tenm’s) with latrophilins (Lphn’s) promotes excitatory synapse formation when Lphn’s simultaneously interact with FLRTs. Insertion of a short alternatively-spliced region within Tenm’s abolishes the Tenm-Lphn interaction and switches Tenm function to specify inhibitory synapses. How Tenm’s bind to Lphn’s in a manner regulated by alternative splicing remains unclear. Here, we report the high-resolution cryo-EM structure of the Tenm2-Lphn3 complex, and describe the trimeric Tenm2-Lphn3-FLRT3 complex. The structure reveals that the N-terminal lectin-like domain of Lphn3 binds to the Tenm2 barrel at a site far away from the alternatively-spliced region. Alternative-splicing regulates the Tenm2-Lphn3 interaction by hindering access to the Lphn-binding surface rather than altering it. Strikingly, mutagenesis of the Lphn-binding surface of Tenm2 abolishes the Lphn3 interaction and impairs excitatory but not inhibitory synapse formation. These results suggest that a multi-level coincident binding mechanism mediated by a cryptic adhesion complex between Tenm’s and Lphn’s regulates synapse specificity.
Species coexistence in resource-limited patterned ecosystems is facilitated by the interplay of spatial self-organisation and intraspecific competition
Authors: Eigentler Lukas
Published: January 2020

The exploration of mechanisms that enable species coexistence under competition for a sole limiting resource is widespread across ecology. Two examples of such facilitative processes are intraspecific competition and spatial self-organisation. These processes determine the outcome of competitive dynamics in many resource-limited patterned ecosystems, classical examples of which include dryland vegetation patterns, intertidal mussel beds and Sub-alpine ribbon forests. Previous theoretical investigations have explained coexistence within patterned ecosystems by making strong assumptions on the differences between species (e.g. contrasting dispersal behaviours or different functional responses to resource availability). In this paper, I show that the interplay between the detrimental effects of intraspecific competition and the facilitative nature of self-organisation forms a coexistence mechanism that does not rely on species-specific assumptions and captures coexistence across a wide range of the environmental stress gradient. I use a theoretical model that captures the interactions of two generic consumer species with an explicitly modelled resource to show that coexistence relies on a balance between species’ colonisation abilities and their local competitiveness, provided intraspecific competition is sufficiently strong. Crucially, the requirements on species’ self-limitation for coexistence to occur differ on opposite ends of the resource input spectrum. For low resource levels, coexistence is facilitated by strong intraspecific dynamics of the species superior in its colonisation abilities, but for larger volumes of resource input, strong intraspecific competition of the locally superior species enables coexistence. Results presented in this paper also highlight the importance of hysteresis in understanding tipping points, in particular extinction events. Finally, the theoretical framework provides insights into spatial species distributions within single patches, supporting verbal hypotheses on co-existence of herbaceous and woody species in dryland vegetation patterns and suggesting potential empirical tests in the context of other patterned ecosystems.
sampbias, a method for quantifying geographic sampling biases in species distribution data
Authors: Zizka Alexander , Antonelli Alexandre , Silvestro Daniele
Published: January 2020

Geo-referenced species occurrences from public databases have become essential to biodiversity research and conservation. However, geographical biases are widely recognized as a factor limiting the usefulness of such data for understanding species diversity and distribution. In particular, differences in sampling intensity across a landscape due to differences in human accessibility are ubiquitous but may differ in strength among taxonomic groups and datasets. Although several factors have been described to influence human access (such as presence of roads, rivers, airports and cities), quantifying their specific and combined effects on recorded occurrence data remains challenging. Here we presentsampbias, an algorithm and software for quantifying the effect of accessibility biases in species occurrence datasets.Sampbiasuses a Bayesian approach to estimate how sampling rates vary as a function of proximity to one or multiple bias factors. The results are comparable among bias factors and datasets. We demonstrate the use ofsampbiason a dataset of mammal occurrences from the island of Borneo, showing a high biasing effect of cities and a moderate effect of roads and airports.Sampbiasis implemented as a well-documented, open-access and user-friendly R package that we hope will become a standard tool for anyone working with species occurrences in ecology, evolution, conservation and related fields.
Abiotic and biotic drivers underly short- and long-term soil respiration responses to experimental warming in a dryland ecosystem
Authors: Dacal Marina , García-Palacios Pablo , Asensio Sergio , Gozalo Beatriz , Ochoa Victoria , Maestre Fernando T.
Published: January 2020

Soil carbon losses to the atmosphere through soil respiration are expected to rise with ongoing temperature increases, but available evidence from mesic biomes suggests that such response disappears after a few years of experimental warming. However, there is lack of empirical basis for these temporal dynamics in soil respiration responses, and of the mechanisms underlying them, in drylands, which collectively form the largest biome on Earth and store 32% of the global soil organic carbon pool. We coupled data from a ten-year warming experiment in a biocrust-dominated dryland ecosystem with laboratory incubations to confront 0-2 years (short-term hereafter) vs. 8-10 years (long-term hereafter) soil respiration responses to warming. Our results showed that increased soil respiration rates with short-term warming observed in areas with high biocrust cover returned to control levels in the long-term. Warming-induced increases in soil temperature were the main driver of the short-term soil respiration responses, whereas long-term soil respiration responses to warming were primarily driven by thermal acclimation and warming-induced reductions in biocrust cover. Our results highlight the importance of evaluating short and long-term soil respiration responses to warming as a mean to reduce the uncertainty in predicting the soil carbon – climate feedback in drylands.
Evolutionary dynamics ofTomato spotted wilt viruswithin and between alternate plant hosts and thrips
Authors: Ruark-Seward Casey L. , Bonville Brian , Kennedy George , Rasmussen David A.
Published: January 2020

Tomato spotted wilt virus (TSWV) is a generalist pathogen with one of the broadest known host ranges among RNA viruses. To understand how TSWV adapts to different hosts, we experimentally passaged viral populations between two alternate hosts,Emilia sochifoliaandDatura stramonium, and an obligate vector in which it also replicates, western flower thrips (Frankliniella occidentalis). Deep sequencing viral populations at multiple time points allowed us to track the evolutionary dynamics of viral populations within and between hosts. High levels of viral genetic diversity were maintained in both plants and thrips between transmission events. Rapid fluctuations in the frequency of amino acid variants indicated strong host-specific selection pressures on proteins involved in viral movement (NSm) and replication (RdRp). While several genetic variants showed opposing fitness effects in different hosts, fitness effects were generally positively correlated between hosts indicating that positive rather than antagonistic pleiotropy is pervasive. These results suggest that high levels of genetic diversity together with the positive pleiotropic effects of mutations have allowed TSWV to rapidly adapt to new hosts and expand its host range.
Selecting forChlamydomonas reinhardtiifitness in a liquid algal growth system compatible with the International Space Station Veggie plant growth chamber
Authors: Zhang Junya , Müller Bárbara S.F. , Tyre Kevin N. , Bai Fang , Hu Ying , Resende Marcio F.R. , Rathinasabapathi Bala , Settles A. Mark
Published: January 2020

A biological life support system for spaceflight would capture carbon dioxide waste produced by living and working in space to generate useful organic compounds. Photosynthesis is the primary mechanism to fix carbon into organic molecules. Microalgae are highly efficient at converting light, water, and carbon dioxide into biomass, particularly under limiting, artificial light conditions that are a necessity in space photosynthetic production. Although there is great promise in developing algae for chemical or food production in space, most spaceflight algae growth studies have been conducted on solid agar-media to avoid handling liquids in microgravity. Here we report that breathable plastic tissue culture bags can support robust growth ofChlamydomonas reinhardtiiin the Veggie plant growth chamber, which is used on the International Space Station to grow terrestrial plants. Live cultures can be stored for at least one month in the bags at room temperature. The gene set required for growth in these photobioreactors was tested through a short-wave ultraviolet light (UVC) mutagenesis and selection experiment with wild-type (CC-5082) andcw15mutant (CC-1883) strains. Genome sequencing identified UVC-induced mutations, which were enriched for transversions and nonsynonymous mutations relative to natural variants among laboratory strains. Genes with mutations indicating positive selection were enriched for information processing genes related to DNA repair, RNA processing, translation, cytoskeletal motors, kinases, and ABC transporters. These data suggest modification of signal transduction and metabolite transport may be needed to improve growth rates in this spaceflight production system.
Distraction attenuates goal-directed neural responses for food rewards
Authors: Duif Iris , Wegman Joost , de Graaf Kees , Smeets Paul A.M. , Aarts Esther
Published: January 2020

Distracted eating can lead to increased food intake, but it is unclear how. We hypothesized that distraction affects the change in motivated responses for food reward after satiation. To investigate this, 38 healthy normal-weight participants (28F, 10M) performed a detection task varying in attentional load (high or low distraction) during fMRI. Simultaneously, they exerted effort for food rewards (sweet or savory) by repeated button presses. Two fMRI runs were separated by outcome devaluation (satiation) of one of the reward outcomes, to assess outcome-sensitive, i.e. goal-directed, responses. Behavioral results showed no effect of distraction on effort for food reward following outcome devaluation. At an uncorrected threshold (p<0.001), distraction decreased goal-directed responses (devalued versus valued) in the right inferior frontal gyrus (rIFG). Importantly, these distraction-sensitive rIFG responses correlated negatively (r= - 0.40,p= 0.014) with the effect of distraction on the number of button presses. Specifically, decreased rIFG responses due to distraction related to increased button presses for food reward after satiation, in line with the rIFG’s established role in response inhibition. Furthermore, distraction decreased functional connectivity between the rIFG (seed) and left putamen for valued versus devalued food rewards (pFWE(cluster)<0.05). Our results suggest that distraction attenuates the ability to inhibit responses for food reward after satiation by affecting the rIFG. Furthermore, distraction attenuated connectivity between two regions involved in response inhibition – rIFG and putamen – after outcome devaluation. These results may explain why distraction can lead to overeating in our current, distracting, environment. The study was preregistered at:https://osf.io/ad2qk.