bluuebunny/crossref_metadata_2025 huggingface dataset:
Senescence impacts reproduction and maternal investment in bottlenose dolphins
Authors: Karniski Caitlin , Krzyszczyk Ewa , Mann Janet
Published: July 2018

Reproductive senescence is evident across many mammalian species. An emerging perspective considers components of reproductive senescence as evolutionarily distinct phenomena: fertility senescence and maternal-effect senescence. While fertility senescence is regarded as the ageing of reproductive physiology, maternal-effect senescence pertains to the declining capacity to provision and rear surviving offspring due to age. Both contribute to reproductive failurein uteromaking it difficult to differentiate between the two prenatally in the wild. We investigated both components in a long-lived mammal with prolonged maternal care through three parameters: calf survival, interbirth interval (IBI) and lactation period. We provide clear evidence for reproductive senescence in a wild population of bottlenose dolphins (Tursiops aduncus) using 34+ years of longitudinal data on 229 adult females and 562 calves. Calf survival decreased with maternal age, and calves with older mothers had lower survival than predicted by birth order, suggesting maternal-effect senescence. Both lactation period and IBIs increased with maternal age, and IBIs increased regardless of calf mortality, indicating interactions between fertility and maternal-effect senescence. Of calves that survived to weaning, last-born calves weaned later than earlier-born calves, evidence of terminal investment, a mitigating strategy given reduced reproductive value caused by either components of reproductive senescence.
Heaviside's dolphins (Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range
Authors: Martin Morgan J. , Gridley Tess , Elwen Simon H. , Jensen Frants H.
Published: July 2018

The costs of predation may exert significant pressure on the mode of communication used by an animal, and many species balance the benefits of communication (e.g. mate attraction) against the potential risk of predation. Four groups of toothed whales have independently evolved narrowband high-frequency (NBHF) echolocation signals. These signals help NBHF species avoid predation through acoustic crypsis by echolocating and communicating at frequencies inaudible to predators such as mammal-eating killer whales. Heaviside's dolphins (Cephalorhynchus heavisidii) are thought to exclusively produce NBHF echolocation clicks with a centroid frequency around 125 kHz and little to no energy below 100 kHz. To test this, we recorded wild Heaviside's dolphins in a sheltered bay in Namibia. We demonstrate that Heaviside's dolphins produce a second type of click with lower frequency and broader bandwidth in a frequency range that is audible to killer whales. These clicks are used in burst-pulses and occasional click series but not foraging buzzes. We evaluate three different hypotheses and conclude that the most likely benefit of these clicks is to decrease transmission directivity and increase conspecific communication range. The expected increase in active space depends on background noise but ranges from 2.5 (Wenz Sea State 6) to 5 times (Wenz Sea State 1) the active space of NBHF signals. This dual click strategy therefore allows these social dolphins to maintain acoustic crypsis during navigation and foraging, and to selectively relax their crypsis to facilitate communication with conspecifics.
An ancient genome duplication in the speciose reef-building coral genus, Acropora
Authors: Mao Yafei , Shinzato Chuya , Satoh Noriyuki
Published: July 2018

Whole-genome duplication (WGD) has been recognized as a significant evolutionary force in the origin and diversification of vertebrates, plants, and other organisms. Acropora, one of the most speciose reef-building coral genera, responsible for creating spectacular but increasingly threatened marine ecosystems, is suspected to have originated by polyploidy, yet there is no genetic evidence to support this hypothesis. Using comprehensive phylogenomic and comparative genomic approaches, we analyzed five Acropora genomes and an Astreopora genome (Scleractinia: Acroporidae) to show that a WGD event likely occurred between 27.9 and 35.7 Million years ago (Mya) in the most recent common ancestor of Acropora, concurrent with a massive worldwide coral extinction. We found that duplicated genes became highly enriched in gene regulation functions, some of which are involved in stress responses. The different functional clusters of duplicated genes are related to the divergence of gene expression patterns during development. Some gene duplications of proteinaceous toxins were generated by WGD in Acropora compared with other Cnidarian species. Collectively, this study provides evidence for an ancient WGD event in corals and it helps to explain the origin and diversification of Acropora.
Macroecological dynamics of gut microbiota
Authors: Ji Brian W. , Sheth Ravi U. , Dixit Purushottam D. , Tchourine Konstantine , Vitkup Dennis
Published: July 2018

The gut microbiome is now widely recognized as a dynamic ecosystem that plays an important role in health and disease1. While current sequencing technologies make it possible to estimate relative abundances of host-associated bacteria over time2, 3, the biological processes governing their dynamics remain poorly understood. Therefore, as in other ecological systems4, 5, it is important to identify quantitative relationships describing global aspects of gut microbiota dynamics. Here we use multiple high-resolution time series data obtained from humans and mice6–8 to demonstrate that despite their inherent complexity, gut microbiota dynamics can be characterized by several robust scaling relationships. Interestingly, these patterns are highly similar to those previously observed across diverse ecological communities and economic systems, including the temporal fluctuations of animal and plant populations9–12 and the performance of publicly traded companies13. Specifically, we find power law relationships describing short- and long-term changes in gut microbiota abundances, species residence and return times, and the connection between the mean and variance of species abundances. The observed scaling relationships are altered in mice receiving different diets and affected by context-specific perturbations in humans. We use these macroecological relationships to reveal specific bacterial taxa whose dynamics are significantly affected by dietary and environmental changes. Overall, our results suggest that a quantitative macroecological framework will be important for characterizing and understanding complex dynamics of microbial communities.
Dispensing a synthetic green leaf volatile to two plant species in a common garden differentially alters physiological responses and herbivory
Authors: Freundlich Grace E. , Shields Maria , Frost Christopher J.
Published: July 2018

Herbivore-induced plant volatile (HIPV)-mediated eavesdropping by plants is a well-documented, inducible phenomenon that has practical agronomic applications for enhancing plant defense and pest management. However, as with any inducible phenomenon, responding to volatile cues may incur physiological and ecological costs that limit plant productivity. In a common garden experiment, we tested the hypothesis that exposure to a single HIPV would decrease herbivore damage at the cost of reduced plant growth and reproduction. Lima bean (Phaseolus lunatus) and pepper (Capsicum annuum) plants were exposed to a persistent, low-dose (∼10ng/hour) of the green leaf volatile cis-3-hexenyl acetate (z3HAC), which is an HIPV and damage-associated volatile. z3HAC-treated pepper plants were shorter, had less aboveground and belowground biomass, and produced fewer flowers and fruits relative to controls while z3HAC-treated lima bean plants were taller and produced more leaves and flowers than did controls. Natural herbivory was reduced in z3HAC-exposed lima bean plants, but not in pepper. Cyanogenic potential, a putative direct defense mechanism in lima bean, was lower in young z3HAC-exposed leaves, suggesting a growth-defense tradeoff from z3HAC exposure alone. Plant species-specific responses to an identical volatile cue have important implications for agronomic costs and benefits of volatile-mediated inter-plant communication under field conditions.
Global Adoption of High-Sensitivity Cardiac Troponins and the Universal Definition of Myocardial Infarction
Authors: Anand Atul , Shah Anoop SV , Beshiri Agim , Jaffe Allan S , Mills Nicholas L
Published: July 2018

Importance

The third Universal Definition of Myocardial Infarction aimed to standardize the approach to the diagnosis and management of myocardial infarction. High-sensitivity cardiac troponin testing was recommended, as these assays have improved precision at low concentrations, but concerns over specificity may have limited implementation.

Objective

To determine the global adoption of high-sensitivity cardiac troponin assays and key recommendations from the Universal Definition.

Design, Setting and Participants

Global survey of 1,902 medical centers across 23 countries evenly distributed across all five continents. Included respondents were involved in the diagnosis and management of patients with suspected acute coronary syndrome at their institutions.

Main Outcomes and Measures

Structured questionnaire detailing the primary biomarker used for myocardial infarction, diagnostic thresholds and critical elements of clinical pathways for comparison to the third Universal Definition recommendations.

Results

Cardiac troponin was the primary diagnostic biomarker for myocardial infarction at 96% of all sites surveyed. Only 41% of centers had adopted high-sensitivity cardiac troponin assays, with wide variation from 7% in North America to 60% in Europe. Sites using high-sensitivity assays more frequently employed serial sampling pathways (91% vs. 78%) and the 99th percentile diagnostic threshold (74% vs. 66%) when compared to sites using the previous generation of troponin assays. Furthermore, sites using high-sensitivity assays more often used earlier serial sampling (≤3 hours) and accelerated diagnostic pathways. However, fewer than 1 in 5 sites using high-sensitivity assays had adopted sex-specific thresholds (18%).

Conclusions and Relevance

Progress has been made in adopting the recommendations of the Universal Definition of Myocardial Infarction, particularly in the use of the 99th percentile diagnostic threshold and serial sampling. However, high-sensitivity assays are used in a minority of sites and sex-specific thresholds in even fewer. These findings highlight regions where additional efforts are required to improve the risk stratification and diagnosis of patients with myocardial infarction.
Genome-wide scan and fine-mapping of rare nonsynonymous associations implicates intracellular lipolysis genes in fat distribution and cardio-metabolic risk
Authors: Lotta Luca A. , Dong Liang , Li Chen , Patel Satish , Stewart Isobel D. , Lim Koini , Day Felix R. , Wheeler Eleanor , Glastonbury Craig A. , Van de Streek Marcel , Sharp Stephen J. , Luan Jian’an , Bowkera Nicholas , Schweiger Martina , Wittemans Laura B. L. , Kerrison Nicola D. , Cai Lina , Lucarelli Debora M. E. , Barroso Inês , McCarthy Mark I. , Scott Robert A. , Zechner Rudolf , Perry John R. B. , Saudek Vladimir , Small Kerrin S. , O’Rahilly Stephen , Wareham Nicholas J. , Savage David B. , Langenberg Claudia
Published: July 2018

Difficulties in identifying causal variants and genes underlying genetic associations have limited the translational potential of genetic studies of body fat distribution, an important, partly-heritable risk factor for cardio-metabolic disease. Rare variant associations facilitate fine-mapping of causal alleles, but their contribution to fat distribution is understudied. We performed a genome-wide scan of rare nonsynonymous variants for body mass index-adjusted waist-to-hip-ratio (BMI-adjusted WHR; a widely-used measure of fat distribution) in 450,562 European ancestry individuals, followed by systematic Bayesian fine-mapping at six genome-wide (p<5×10−08; main-analysis) and two subthreshold signals (significant at a Bonferroni-corrected p<1.3×10−06). We found strong statistical evidence of causal association for nonsynonymous alleles in CALCRL (p.L87P, pconditional=5.9×10−12; posterior-probability of association [PPA]=52%), PLIN1 (p.L90P, pconditional=5.5×10−13; PPA>99%), PDE3B (p.R783X, pconditional=6.2×10−15; PPA>99%), ACVR1C (p.I195T; pconditional=5.4×10−12; PPA>99%), and FGF1 (p.G21E, pconditional=1.6×10−07; PPA=98%). Alleles at the four likely-causal main-analysis genes affected fat distribution primarily via larger hip-rather than smaller waist-circumference and six of nine conditionally-independent WHR-lowering index-variants were associated with protection from cardiovascular or metabolic disease. All four genes are expressed in adipose tissue and have been linked with the regulation of intracellular lipolysis, which controls fat retention in mature cells. Targeted follow-up analyses of key intracellular-lipolysis genes revealed associations for a variant in the initiator of intracellular lipolysis PNPLA2 (p.N252K) with higher BMI-adjusted-WHR and higher cardio-metabolic risk. This study provides human genetic evidence of a link between intracellular lipolysis, fat-distribution and its cardio-metabolic complications in the general population.
Regeneration of the zebrafish retinal pigment epithelium after widespread genetic ablation
Authors: Hanovice Nicholas J. , Leach Lyndsay L. , Slater Kayleigh , Gabriel Ana E. , Romanovicz Dwight , Shao Enhua , Collery Ross , Burton Edward A. , Lathrop Kira , Link Brian A. , Gross Jeffrey M.
Published: July 2018

The retinal pigment epithelium (RPE) is a specialized monolayer of pigmented cells within the eye that is critical for maintaining visual system function. Diseases affecting the RPE have dire consequences for vision, and the most prevalent of these is atrophic (dry) age-related macular degeneration (AMD), which is thought to result from RPE dysfunction and degeneration. An intriguing possibility for treating RPE degenerative diseases like atrophic AMD is the stimulation of endogenous RPE regeneration; however, very little is known about the mechanisms driving successful RPE regenerationin vivo. Here, we developed a zebrafish transgenic model (rpe65a:nfsB-GFP) that enabled ablation of large swathes of mature RPE. RPE ablation resulted in rapid RPE degeneration, as well as degeneration of Bruch’s membrane and underlying photoreceptors. Using this model, we demonstrate for the first time that larval and adult zebrafish are capable of regenerating a functional RPE monolayer after RPE ablation. Regenerated RPE cells first appear at the periphery of the RPE, and regeneration proceeds in a peripheral-to-central fashion. RPE ablation elicits a robust proliferative response in the remaining RPE. Subsequently, proliferative cells move into the injury site and differentiate into RPE. BrdU pulse-chase analyses demonstrate that the regenerated RPE is likely derived from remaining peripheral RPE cells. Pharmacological inhibition of Wnt signaling significantly reduces cell proliferation in the RPE and delays overall RPE recovery. These data demonstrate that the zebrafish RPE possesses a robust capacity for regeneration and highlight a potential mechanism through which endogenous RPE regeneratein vivo.

SIGNIFICANCE STATEMENT

Diseases resulting in RPE degeneration are among the leading causes of blindness worldwide, and no therapy exists that can replace RPE or restore lost vision. One intriguing possibility is the development of therapies focused on stimulating endogenous RPE regeneration. For this to be possible, we must first gain a deeper understanding of the mechanisms underlying RPE regeneration. Here, we ablate mature RPE in zebrafish and demonstrate that zebrafish regenerate RPE after widespread injury. Injury-adjacent RPE proliferate and regenerate RPE, suggesting that they are the source of regenerated tissue. Finally, we demonstrate that Wnt signaling is required for RPE regeneration. These findings establish anin vivomodel through which the molecular and cellular underpinnings of RPE regeneration can be further characterized.
The high abortion cost of human reproduction
Authors: Rice William R.
Published: July 2018

Information from many large data bases and published studies was integrated to estimate the age-specific spontaneous abortion rate in an economically-developed human population. Accuracy was tested with published data from a diverse array of studies. Spontaneous abortion was found to be: i) the predominant outcome of fertilization and ii) a natural and inevitable part of human reproduction at all ages. The decision to reproduce is inextricably coupled with the production of spontaneous abortions with high probability, and the decision to have a large family leads to many spontaneous abortions with virtual certainty. The lifetime number of spontaneous abortions was estimated for a “canonical” woman (constrained to have average age at marriage, first birth, inter-birth intervals, and family size) in two populations: one with and the other without effective birth control (including free access to elective abortions). Birth control was found to reduce lifetime abortions more than 6-fold.
Studies of NH4+ and NO3- uptake ability of subalpine plants and resource-use strategy identified by their functional traits
Authors: Nicolas Legay , Fabrice Grassein , Cindy Arnoldi , Raphaël Segura , Philippe Laîné , Sandra Lavorel , Jean-Christophe Clément
Published: July 2018

Abstract

The leaf economics spectrum (LES) is based on a suite of leaf traits related to plant functioning and ranges from resource-conservative to resource-acquisitive strategies. However, the relationships with root traits, and the associated belowground plant functioning such as N uptake, including nitrate (NO3-) and ammonium (NH4+), is still poorly known. Additionally, environmental variations occurring both in time and in space could uncouple LES from root traits. We explored, in subalpine grasslands, the relationships between leaf and root morphological traits for 3 dominant perennial grass species, and to what extent they contribute to the whole-plant economics spectrum. We also investigated the link between this spectrum and NO3- and NH4+ uptake rates, as well as the variations of uptake across four grasslands differing by the land-use history at peak biomass and in autumn. Although poorly correlated with leaf traits, root traits contributed to an economic spectrum at the whole plant level. Higher NH4+ and NO3- uptake abilities were associated with the resource-acquisitive strategy.

Nonetheless, NH4+ and NO3- uptake within species varied between land-uses and with sampling time, suggesting that LES and plant traits are good, but still incomplete, descriptors of plant functioning. Although the NH4+: NO3- uptake ratio was different between plant species in our study, they all showed a preference for NH4+, and particularly the most conservative species. Soil environmental variations between grasslands and sampling times may also drive to some extent the NH4+ and NO3- uptake ability of species. Our results support the current efforts to build a more general framework including above- and below-ground processes when studying plant community functioning.
Spatial Control of Neuronal Metabolism Through Glucose-Mediated Mitochondrial Transport Regulation
Authors: Agrawal Anamika , Pekkurnaz Gulcin , Koslover Elena F.
Published: July 2018

Eukaryotic cells modulate their metabolism by organizing metabolic components in response to varying nutrient availability and energy demands. In the axons of mammalian neurons, mitochondria have been shown to respond to glucose levels by halting active transport preferentially in high glucose regions. Here, we employ quantitative modeling to explore the physical limits on spatial organization of organelles through such regulated stopping of processive motion, as well as the consequences to cellular metabolism. We delineate the role of key parameters, including cellular glucose uptake and consumption rates, that are expected to modulate mitochondrial distribution and metabolic response in spatially varying glucose conditions. Our quantitative estimates indicate that physiological brain glucose levels fall within the limited range necessary for metabolic enhancement, making this a plausible regulatory mechanism for neuronal metabolic flexibility in the presence of spatially heterogeneous glucose. These findings highlight the role of spatial organization in the regulation of neuronal metabolism, while providing a quantitative framework for the establishment of such organization by control of organelle trafficking.
Response to Fraser & Wark's comments on A new theory for X-ray diffraction
Authors: Fewster Paul F.
Published: July 2018

The criticisms of my theory, as given by Fraser & Wark [(2018), Acta Cryst. A74, 447–456], are built on a misunderstanding of the concept and the methodology I have used. The assumption they have made rules out my description from which they conclude that my theory is proved to be wrong. They assume that I have misunderstood the diffraction associated with the shape of a crystal and my calculation is only relevant to a parallelepiped and even that I have got wrong. It only appears wrong to Fraser & Wark because the effect I predict has nothing to do with the crystal shape. The effect though can be measured as well as the crystal shape effects. This response describes my reasoning behind the theory, how it can be related to the Ewald sphere construction, and the build-up of the full diffraction pattern from all the scatterers in a stack of planes. It is the latter point that makes the Fraser & Wark analysis incomplete. The description given in this article describes my approach much more precisely with reference to the Ewald sphere construction. Several experiments are described that directly measure the predictions of the new theory, which are explained with reference to the Ewald sphere description. In its simplest terms the new theory can be considered as giving a thickness to the Ewald sphere surface, whereas in the conventional theory it has no thickness. Any thickness immediately informs us that the scattering from a peak at the Bragg angle does not have to be in the Bragg condition to be observed. I believe the conventional theory is a very good approximation, but as soon as it is tested with careful experiments it is shown to be incomplete. The new theory puts forward the idea that there is persistent intensity at the Bragg scattering angle outside the Bragg condition. This intensity is weak (∼10−5) but can be observed in careful laboratory experiments, despite being on the limit of observation, yet it has a profound impact on how we should interpret diffraction patterns.
Autonomous navigation algorithm based on AUKF filter about fusion of geomagnetic and sunlight directions
Authors: Hua Bing , Zhang Zhiwen , Wu Yunhua , Chen Zhiming
Published: July 2018

Purpose

The geomagnetic field vector is a function of the satellite’s position. The position and speed of the satellite can be determined by comparing the geomagnetic field vector measured by on board three-axis magnetometer with the standard value of the international geomagnetic field. The geomagnetic model has the disadvantages of uncertainty, low precision and long-term variability. Therefore, accuracy of autonomous navigation using the magnetometer is low. The purpose of this paper is to use the geomagnetic and sunlight information fusion algorithm to improve the orbit accuracy.

Design/methodology/approach

In this paper, an autonomous navigation method for low earth orbit satellite is studied by fusing geomagnetic and solar energy information. The algorithm selects the cosine value of the angle between the solar light vector and the geomagnetic vector, and the geomagnetic field intensity as observation. The Adaptive Unscented Kalman Filter (AUKF) filter is used to estimate the speed and position of the satellite, and the simulation research is carried out. This paper also made the same study using the UKF filter for comparison with the AUKF filter.

Findings

The algorithm of adding the sun direction vector information improves the positioning accuracy compared with the simple geomagnetic navigation, and the convergence and stability of the filter are better. The navigation error does not accumulate with time and has engineering application value. It also can be seen that AUKF filtering accuracy is better than UKF filtering accuracy.

Research limitations/implications

Geomagnetic navigation is greatly affected by the accuracy of magnetometer. This paper does not consider the spacecraft’s environmental interference with magnetic sensors.

Practical implications

Magnetometers and solar sensors are common sensors for micro-satellites. Near-Earth satellite orbit has abundant geomagnetic field resources. Therefore, the algorithm will have higher engineering significance in the practical application of low orbit micro-satellites orbit determination.

Originality/value

This paper introduces a satellite autonomous navigation algorithm. The AUKF geomagnetic filter algorithm using sunlight information can obviously improve the navigation accuracy and meet the basic requirements of low orbit small satellite orbit determination.
A defects detection method based on infrared scanning in laser metal deposition process
Authors: Xie Ruidong , Li Dichen , Cui Bin , Zhang Lianzhong , Gao Feng
Published: July 2018

Purpose

Laser metal deposition (LMD) is an important additive manufacturing (AM) technology, but the metallurgical defects, such as cracks and porosities, produced in LMD process will seriously affect the mechanical properties of the parts. The purpose of this paper is to propose a novel in-process defects detection method based on infrared scanning for LMD.

Design/methodology/approach

The defects detection principle is that, after every three to five layers have been deposited, the optical head of a high-precision infrared two-color pyrometer is driven to scan the defects by measuring the abnormal temperature peaks on the deposited surface. The experiments for verifying the defects detection principle were carried out.

Findings

The relationship between the temperature peak value and the dimensions of the defect was analyzed based on the heat conduction theory and curves of temperature peak value versus crack width or diameter of porosity.

Originality/value

This method can effectively improve the detection accuracy and the defects can be precisely located, which can meet the requirement of laser targeting re-melting and elimination of the defects.
CITES‐listed sharks remain among the top species in the contemporary fin trade
Authors: Cardeñosa Diego , Fields Andrew T. , Babcock Elizabeth A. , Zhang Huarong , Feldheim Kevin , Shea Stanley K. H. , Fischer Gunter A. , Chapman Demian D.
Published: July 2018

Trade‐driven overexploitation threatens many sharks. Twelve of the world's most vulnerable shark species have been listed on the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) to regulate internationally traded products such as meat and dried fins. CITES records indicate that Hong Kong was the world's top legal importer of dried fins from listed sharks in 2015 (N = 8 species at that time), but traded a relatively small volume, with a few partners, in a small number of shipments (16). In contrast two CITES Appendix II listed hammerheads were consistently the fourth and fifth most common species (out of >80) in processed fin trimmings (N = 9,200) collected randomly from the Hong Kong retail dried fin market from February 2014 to December 2016 and were found in 100% of sampling events and in 66% of sampled retail vendors. This difference, and the fact that exporting nations previously known to land these species were not among those to report trade to CITES, suggest that listed species were often imported without CITES documentation in 2015. There are a number of incentives for trade hubs to meet their obligations to this treaty, which they could achieve by scaling up monitoring capacity and increasing inspection efficiency.
Factors associated with vocational disengagement among young people entering mental health treatment
Authors: Caruana Emma , Allott Kelly , Farhall John , Parrish Emma M. , Davey Christopher G. , Chanen Andrew M. , Killackey Eoin , Cotton Susan M.
Published: July 2018

Aim

Most mental disorders have their onset by age 25, disrupting normative vocational engagement. Factors associated with vocational disengagement at first contact with specialist treatment are important for service planning. The aim of this paper was to investigate the association between theoretically important factors and vocational disengagement for youth entering mental health treatment.

Methods

A file audit was used to extract vocational data of 145 young people aged 15 to 25 years entering treatment in 2011 at a public youth mental health service in Melbourne, Australia. Comparisons were made across three specialist programs for: psychosis (n = 50), mood disorders (n = 52) and borderline personality pathology (n = 43). Individual characteristics were entered into univariate and multivariate logistic regressions to investigate their associations with vocational disengagement.

Results

Educational disengagement was associated with being older (OR = 4.38, P = 0.004) and not living with parents (OR = 2.87, P = 0.038). Unemployment and being NEET (Not in Education, Employment or Training) were both associated with not having commenced tertiary education (OR = 0.23, P = 0.022; OR = 0.05, P = 0.002; respectively). Being NEET was also associated with being older (OR = 6.18, P = 0.004). Primary diagnostic grouping was not associated with vocational disengagement, once accounting for other factors.

Conclusions

The likelihood of vocational disengagement did not differ across disorder groups, implying that intervention should be “transdiagnostic” and might best target education first, specifically post‐secondary qualifications. Other domains or variables not measured in this study are also likely to be important, and this might include young people's support systems and symptom severity. Qualitative studies may be useful for exploring further factors relevant to vocational engagement.
Emergency department neuroimaging for epileptic seizures
Authors: Salinsky Martin , Wong Victoria S. S. , Motika Paul , Meuse Justin , Nguyen Joseph
Published: July 2018

Objective

To determine the frequency and yield of neuroimaging in patients with known seizure disorders presenting to the emergency department (ED) with recurrent (nonindex) seizures.

Methods

We reviewed 822 consecutive ED visits for nonindex seizures at the Oregon Health & Science University and the VA Portland Health Care System. For each visit, we abstracted details of the clinical presentation, whether neuroimaging was obtained, the results of neuroimaging, and the results of previous neuroimaging studies, when available. We determined whether ED neuroimaging led to an acute change in patient management (yield). Clinical factors associated with obtaining ED neuroimaging, and with the yield of neuroimaging, were evaluated by multivariate logistic regression.

Results

A majority (78%) of ED seizure visits were for nonindex seizures. Neuroimaging was obtained in 381 of 822 nonindex seizure visits (46%). Of these, 11 imaging studies (3%) led to an acute change in patient management, 8 (2%) after excluding false‐positive scans. Acute head trauma, prolonged alteration of consciousness, and a focal neurologic examination at presentation were associated with an increased yield of ED neuroimaging. Absent any of these 3 clinical factors the true positive yield of neuroimaging was zero.

Significance

ED neuroimaging was performed in nearly half of all patients presenting with nonindex seizures. A more conservative use of ED neuroimaging for nonindex seizures, based on clinical factors at presentation, could decrease imaging frequency with minimal loss of yield.
Humiliation as a Harm of Sexual Violence: Feminist versus Neoliberal Perspectives
Authors: Taylor Dianna
Published: July 2018

This essay provides an account of humiliation as a manifestation of the relationship one has to oneself. This account elucidates two important insights: first, that all sexual violence and not only public gang rape humiliates and, second, that appeals to the neoliberal notion of resilience undermine feminist efforts to counter sexual violence. The first part of the essay provides an overview of the idea of a relation of self to self and its significance, presents humiliation specifically as a manifestation of the self‐relation, and then turns to feminist analyses of sexual violence and its effects in order to illustrate how sexual violence against women humiliates. The second part of the essay illustrates that, given the nature and function of humiliation, neoliberal discourse generally and that of resilience more specifically reproduce the individuation and exclusion that characterize humiliation and are thus detrimental to feminist efforts toward countering sexual violence against women. I conclude by encouraging feminist anti‐sexual violence efforts that at least counter individuation and at best promote collective and inclusive solidarity.
Household chaos during infancy and infant weight status at 12 months
Authors: Khatiwada A. , Shoaibi A. , Neelon B. , Emond J. A. , Benjamin‐Neelon S. E.
Published: July 2018

Background

Infancy is a critical period for obesity prevention. Emerging evidence links household chaos to poor health outcomes, yet its impact on obesity in infancy is unknown.

Objectives

We examined associations between household chaos when infants were 6 and 12 months and weight‐for‐length (WFL) z‐score at 12 months, exploring potential mediation by infant sleep and screen time.

Methods

We examined 401 predominately Black women and infants in the southeastern United States. We conducted multivariable linear regressions examining household chaos and infant WFL z‐score, assessing breastfeeding, sleep, screen time as potential mediators.

Results

Among infants, 69.7% were Black and 49.0% were female. Mean breasting duration was 3.7 months. Over half (50.4%) of families had annual household incomes <$20 000. After adjustment for potential confounders, household chaos was associated with infant WFL z‐score (0.02; 95% CI 0.001, 0.04; p = 0.04) at 12 months. We did not observe associations between chaos and infant breastfeeding, sleep or screen time.

Conclusions

Higher household chaos was associated with greater infant weight at 12 months, but there was no evidence of mediation by breastfeeding, sleep or screen time.
Neural processing of food cues in pre‐pubertal children
Authors: Luo S. , Alves J. , Hardy K. , Wang X. , Monterosso J. , Xiang A. H. , Page K. A.
Published: July 2018

Background/Objectives

Neuroimaging investigations of brain pathways involved in reward and motivation have primarily focused on adults. This study sought to identify brain responses to visual food cues and explore its relationships with adiposity and sex in pre‐pubertal children.

Methods

Brain responses to palatable food vs. non‐food cues were measured in 53 children (age: 8.18 ± .66 years; sex: 22 boys, 31 girls) after an overnight fast. Whole‐brain analysis (cluster‐correction Z > 2.3, P < .05) was performed to examine brain food cue reactivity and its relationships with adiposity and sex.

Results

Greater brain activity in response to food vs. non‐food cues was observed in regions implicated in reward (orbital frontal cortex, striatum), taste (insula, postcentral gyrus), appetite (hypothalamus), emotion (amygdala), memory (hippocampus), visual processing (occipital cortex) and attention (parietal cortex). A negative association was found between percent body fat and food cue reactivity in the medial prefrontal cortex and lateral orbital frontal cortex adjusting for age and sex. Boys compared with girls had increased food cue reactivity in right hippocampus and visual cortex.

Conclusions

These data suggest that body fat and sex are important moderators of brain food cue reactivity in children.
Seeing the Forest and the Trees: How a Systems Perspective Informs Paradox Research
Authors: Schad Jonathan , Bansal Pratima
Published: July 2018

Paradox theory has fundamentally changed how researchers think about organizational tensions by emphasizing their oppositionsandtheir interdependencies. Yet, most paradox studies focus on salient, perceived tensions, ignoring latent, nested tensions and their complex interconnections. This partial view is rooted in the paradox literature focusing on the epistemological realm (actors’ perception of tensions) while disregarding the ontological realm (tensions’ underlying reality). The focus on the epistemological aspects of the tensions impedes researchers from moving to more intricate insights into paradox, which could help address the realities of complex issues, such as wicked problems. We propose a systems perspective on paradox that discriminates the epistemological understandings from the ontological realities of tensions. By revealing the ontology of tensions, the underlying complexity becomes empirically interpretable. We illustrate the power of this perspective by offering two research strategies that can help researchers and organizations apprehend paradoxes grounded in systems.
Effect of target properties and impact velocity on ejection dynamics and ejecta deposition
Authors: Luther Robert , Zhu Meng‐Hua , Collins Gareth , Wünnemann Kai
Published: July 2018

Impact craters are formed by the displacement and ejection of target material. Ejection angles and speeds during the excavation process depend on specific target properties. In order to quantify the influence of the constitutive properties of the target and impact velocity on ejection trajectories, we present the results of a systematic numerical parameter study. We have carried out a suite of numerical simulations of impact scenarios with different coefficients of friction (0.0–1.0), porosities (0–42%), and cohesions (0–150 MPa). Furthermore, simulations with varying pairs of impact velocity (1–20 km s−1) and projectile mass yielding craters of approximately equal volume are examined. We record ejection speed, ejection angle, and the mass of ejected material to determine parameters in scaling relationships, and to calculate the thickness of deposited ejecta by assuming analytical parabolic trajectories under Earth gravity. For the resulting deposits, we parameterize the thickness as a function of radial distance by a power law. We find that strength—that is, the coefficient of friction and target cohesion—has the strongest effect on the distribution of ejecta. In contrast, ejecta thickness as a function of distance is very similar for different target porosities and for varying impact velocities larger than ~6 km s−1. We compare the derived ejecta deposits with observations from natural craters and experiments.
Foetal ultrasound measurement imputations based on growth curves versus multiple imputation chained equation (MICE)
Authors: Ferguson Kelly K. , Yu Youfei , Cantonwine David E. , McElrath Thomas F. , Meeker John D. , Mukherjee Bhramar
Published: July 2018

Background

Ultrasound measures are valuable for epidemiologic studies of risk factors for growth restriction. Longitudinal measurements enable investigation of rates of change and identification of windows where growth is impacted more acutely. However, missing data can be problematic in these studies, limiting sample size, ability to characterise windows of vulnerability, and in some instances creating bias. We sought to compare a parametric linear mixed model (LMM) approach to multiple imputation in this setting with multiple imputation by chained equation (MICE) methodology.

Methods

Ultrasound scans performed for clinical purposes were abstracted from women in the LIFECODES birth cohort (n = 1003) if they were close in time to three study visits (median 18, 26, and 35 weeks’ gestation). We created imputed datasets using LMM and MICE and calculated associations between demographic factors and ultrasound parameters cross‐sectionally and longitudinally. Results were compared with a complete‐case analysis.

Results

Most participants had ultrasounds at 18 weeks’ gestation, and ~50% had measurements at 26 and 35 weeks; 100% had birthweight. Associations between demographic factors and ultrasound measures were similar in magnitude, but more precise, when either imputed datasets were used, compared with a complete‐case analysis, in both the cross‐sectional or longitudinal analyses.

Conclusions

MICE, though ignoring the non‐linear features of the trajectory and within subject correlation, is able to provide reasonable imputation of foetal growth data when compared to LMM. Because it simultaneously imputes missing covariate data and does not require specification of variance structure as in LMM, MICE may be preferable for imputation in this setting.
The novel HLA‐DRB1*15:149 allele discovered in a Taiwanese individual
Authors: Yang K. L. , Lin P. Y.
Published: July 2018

One nucleotide substitution at residue 85 of HLA‐DRB1*15:02:01:01 results in a new allele, HLA‐DRB1*15:149.
Chern class formulas for classical-type degeneracy loci
Authors: Anderson David , Fulton William
Published: July 2018

Employing a simple and direct geometric approach, we prove formulas for a large class of degeneracy loci in types B, C, and D, including those coming from all isotropic Grassmannians. The results unify and generalize previous Pfaffian and determinantal formulas. Specializing to the Grassmannian case, we recover the remarkable theta- and eta-polynomials of Buch, Kresch, Tamvakis, and Wilson. Our method yields streamlined proofs which proceed in parallel for all four classical types, substantially simplifying previous work on the subject. In an appendix, we develop some foundational algebra and prove several Pfaffian identities. Another appendix establishes a basic formula for classes in quadric bundles.
Effect of Thermal Barrier Coating and Gas Radiation on Film Cooling of a Corrugated Surface
Authors: Singh Kuldeep , Premachandran B. , Ravi M. R.
Published: July 2018

In this work, a numerical study is conducted to investigate film cooling of a corrugated surface. A conjugate heat transfer analysis is carried out, accounting for the presence of thermal barrier coating (TBC) and gas radiation. The Mach number of mainstream flow is maintained at Ma = 0.6, while cold stream Mach number is varied from 0.3 to 0.58, and density ratio is kept 4. From this study, it is observed that the overall film cooling effectiveness increases by a value ranging from 0.10 to 0.15 with the use of TBC. The hot side metallic wall temperature increases in the range of 100–150 °C when the effect of gas radiation is considered. It is also found that the film cooling effectiveness decreases with decrease in the cold side Mach number.
Fractional Boundary Layer Flow and Heat Transfer Over a Stretching Sheet With Variable Thickness
Authors: Liu Lin , Zheng Liancun , Chen Yanping , Liu Fawang
Published: July 2018

The paper gives a comprehensive study on the space fractional boundary layer flow and heat transfer over a stretching sheet with variable thickness, and the variable magnetic field is applied. Novel governing equations with left and right Riemann–Liouville fractional derivatives subject to irregular region are formulated. By introducing new variables, the boundary conditions change as the traditional ones. Solutions of the governing equations are obtained numerically where the shifted Grünwald formulae are applied. Good agreement is obtained between the numerical solutions and exact solutions which are constructed by introducing new source items. Dynamic characteristics with the effects of involved parameters on the velocity and temperature distributions are shown and discussed by graphical illustrations. Results show that the velocity boundary layer is thicker for a larger fractional parameter or a smaller magnetic parameter, while the temperature boundary layer is thicker for a larger fractional parameter, a smaller exponent parameter, or a larger magnetic parameter. Moreover, it is thicker at a smaller y and thinner at a larger y for the velocity boundary layer with a larger exponent parameter while for the velocity and temperature boundary layers with a smaller weight coefficient.
Particle-Scale Investigation of Thermal Radiation in Nuclear Packed Pebble Beds
Authors: Wu Hao , Gui Nan , Yang Xingtuan , Tu Jiyuan , Jiang Shengyao
Published: July 2018

For the heat transfer of pebble or granular beds (e.g., high temperature gas-cooled reactors (HTGR)), the particle thermal radiation is an important part. Using the subcell radiation model (SCM), which is a generic theoretical approach to predict effective thermal conductivity (ETC) of particle radiation, particle-scale investigation of the nuclear packed pebble beds filled with monosized or multicomponent pebbles is performed here. When the radial porosity distribution is considered, the ETC of the particle radiation decreases significantly at near-wall region. It is shown that radiation exchange factor increases with the surface emissivity. The results of the SCM under different surface emissivity are in good agreement with the existing correlations. The discrete heat transfer model in particle scale is presented, which combines discrete element method (DEM) and particle radiation model, and is validated by the transient experimental results. Compared with the discrete simulation results of polydisperse beds, it is found that the SCM with the effective particle diameter can be used to analyze behavior of the radiation in polydisperse beds.
Optimizing the Interfacial Thermal Conductance at Gold–Alkane Junctions From “First Principles”
Authors: Zhang Jingjie , Polanco Carlos A. , Ghosh Avik W.
Published: July 2018

We theoretically explore the influence of end-group chemistry (bond stiffness and mass) on the interfacial thermal conductance at a gold–alkane interface. We accomplish this using the nonequilibrium Green's function (NEGF) coupled with first principle parameters in density functional theory (DFT) within the harmonic approximation. Our results indicate that the interfacial thermal conductance is not a monotonic function of either chemical parameters but instead maximizes at an optimal set of mass and bonding strength. This maximum is a result of the interplay between the overlap in local density of states (LDOS) of the device and that in the contacts, as well as the phonon group velocity. We also demonstrate the intrinsic relationship between the diffusive mismatch model (DMM) and the properties from NEGF, and provide an approach to get DMM from first principles NEGF. By comparing the NEGF-based DMM conductance and range of conductance while altering the mass and bonding strength, we show that DMM provides an upper bound for elastic transport in this dimension-mismatched system. We thus have a prescription to enhance the thermal conductance of systems at low temperatures or at low dimensions where inelastic scattering is considerably suppressed.
China’s livestock transition: Driving forces, impacts, and consequences
Authors: Bai Zhaohai , Ma Wenqi , Ma Lin , Velthof Gerard L. , Wei Zhibiao , Havlík Petr , Oenema Oene , Lee Michael R. F. , Zhang Fusuo
Published: July 2018

After significant increases in livestock productivity, China now needs to improve efficiency and environmental performance.
The equation of motion for supershear frictional rupture fronts
Authors: Kammer David S. , Svetlizky Ilya , Cohen Gil , Fineberg Jay
Published: July 2018

Fracture mechanics shows how supershear ruptures evolve within frictional interfaces and, possibly, natural faults.
Optimized flocking of autonomous drones in confined environments
Authors: Vásárhelyi Gábor , Virágh Csaba , Somorjai Gergő , Nepusz Tamás , Eiben Agoston E. , Vicsek Tamás
Published: July 2018

A flocking model that uses an evolutionary optimization framework is validated with a self-organized swarm of 30 drones.