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Increasing evidence suggests that nearshore turbid coral reefs may mitigate bleaching of reef building calcifiers and play a critical role in the future of marine biodiversity in coastal areas. However, biomineralization processes on turbid reefs are relatively understudied compared to clear water counterparts and most published work focuses on corals. Here, we investigate how the mixotrophic giant clam Tridacna squamosa, a bivalve with ecological, cultural and economic significance, grows across a mosaic of less turbid to turbid reefs in the Coral Triangle. We construct growth chronologies from live and dead collected shells by measuring daily growth increments with petrography and scanning electron microscopy (SEM) to gain insight into growth rate on daily, seasonal and annual scales. We find annual growth is not significantly different across a turbidity gradient when scaled to ontogeny, while seasonal growth highly varies. Kd(490) (a measurement positively correlated with turbidity) and chlorophyll-a are likely important factors driving seasonal growth on a turbid reef near a river, compared to sea surface temperature (SST), cloud cover and rainfall on a less turbid reef. On a daily scale, we investigate increment microstructure and spectral characteristics of chronologies, finding a relationship between tidal range and daily increments. Overall, our results indicate that light-enhanced calcification is likely most important in the less turbid reef, compared to heterotrophic feeding in the turbid reef. The trophic plasticity of T. squamosa may allow for its sustained growth in marginal conditions, supporting evidence that these habitats serve as important conservation hotspots for diverse reef building taxa.

The isohydric-anisohydric continuum describes the relative stringency of stomatal control of leaf water potential (ψ

Background Despite the recognized importance of hydraulic capacitance as a mechanism utilized by plants to maintain hydraulic functioning during high transpiration, characterizing the dynamics of capacitance remains a challenge. Methods We used a novel "two-balance method" to investigate relationships between stem rehydration kinetics and other hydraulic traits in multiple tree species and we developed a model to further explore stem rehydration kinetics. Key Results We found that: (1) rehydration time constants and the amount of water uptake occurring during rehydration differed significantly across species; (2) time constants did not change with declining water potential (Ψ) while water uptake increased at lower Ψin some species; (3) longer time constants were associated with lower wood density, higher capacitance and less negative stem pressures causing 50% loss of hydraulic conductivity (P50); (4) greater water uptake occurred in stems with lower wood density and less negative P50 values; and (5) the model could estimate the total hydraulic resistance of the rehydration path, which cannot be measured directly. Conclusions Overall, the two-balance method can be used to quickly and thoroughly examine rehydration dynamics in detached woody stems. This method has the potential to improve our understanding of how capacitance functions across tree species, which is an often-overlooked component of whole-plant hydraulics.

The compositions of resistant indicator minerals are diagnostic of their original host environment. They may be used to fingerprint different types of mineral deposit as well as vector towards them. We have characterised the composition of apatite and Fe–Ti oxides in variably mineralised mafic–ultramafic rock units of the Montagnais Sill Complex in the Labrador Trough to assess their suitability for vectoring towards magmatic sulphide occurrences. Two broad types of apatite were identified: (i) fluoro- to hydroxy-apatite (Cl/(Cl+F) < 0.2); and (ii) chloro- to hydroxy-apatite (Cl/(Cl+F) > 0.5). The former reflects variable degrees of degassing and Cl loss during Rayleigh fractionation and is not indicative of Ni–Cu mineralisation or host rock. The latter exists only in sulphidic olivine cumulate units and thus may be used to vector towards similar rock types in the Labrador Trough. Ilmenite is the dominant oxide, except for the upper parts of differentiated gabbroic sills in which titanomagnetite is dominant. Magnetite occurs only as a secondary phase in serpentinised olivine cumulates and is not discriminative for magmatic sulphides. Ilmenite and titanomagnetite in the sulphidic olivine-bearing units have characteristically high Mg (∼1000–10 000 ppm), Cr (∼100–1000 ppm), and Ni (∼10–1000 ppm) concentrations relative to those from other rock units. Their composition is consistent with Fe–Ti oxides derived from evolved sulphide melts in ultramafic-hosted Ni–Cu–(PGE) sulphide deposits and thus may be used to vector towards similar magmatic sulphide occurrences in the Labrador Trough.

SummaryA systematic monograph is presented for Hydnora (Hydnoraceae), a poorly known genus of holoparasitic plants distributed across Africa, Madagascar and southern Arabia. Species ofHydnoraare characterised by their underground habit, unusual fleshy flowers and complete absence of leaves or photosynthetic tissue. This is the first detailed monograph of the genus Hydnora since 1935 and is informed by a comprehensive survey of herbarium specimens and literature. Detailed descriptions, full synonymy, distribution maps and discussion concerning confusable taxa are provided for each species, along notes on ethnobotany, ecology and conservation. We place particular emphasis on the taxonomic value of osmophore geometry and positioning in living and dried material, which are highly consistent within species. We also provide the first detailed assessment of host range across the genus.Hydnora hanningtoniiRendle andH. solmsianaDinter are reinstated from synonymy, andH. boliniiHatt is newly described here. The infrageneric classification is reviewed and a key is provided for both living and dried material. Species are accompanied by both illustrations and photographs of living and dried material where possible.

The increasing use of soilless cultivation for the production of fruit and vegetable crops allows for constant innovation and development of new soilless growing media. Flexible polyurethane foams (fPUF) have many of the properties required for this purpose. They have the mechanical strength to anchor plants and their highly porous nature allows for liquid and gas transfer to occur in the polymer foam cells. However, the optimum PUF physical properties required for efficient plant growth have not been well explored. Design of experiment (DoE) techniques were used to generate 15 fPUF's with a large range of select properties by varying catalyst and surfactant ratios. Density, cell size, water holding capacity (WHC), water drop penetration time (WDPT) and airflow were selected as foam properties likely to influence plant growth. Airflow ranged between 0.970-108 L min-1, foam cell size ranged between 0.966-1.98 mm, density of foams ranged between 30.4-41.9 kg m-3, WDPT ranged between 0.500-6050 s and WHC ranged between 204-966 gH2O Lfoam-1. Spring onions (Allium cepa) were grown hydroponically in the fPUF and plant height, dry shoot mass, nitrogen content and phosphorus content were measured. These response variables were modeled using the foam physical properties as factors. Water holding as well as the foam cell size were the only significant factors in determining the plant height, nitrogen content and phosphorus content. Water holding, cell size as well as airflow through the foam were significant factors in predicting the dry plant mass. All responses were successfully modeled using a DoE framework, indicating the strength of such a methodology in optimising fPUF as a soilless growing media.

Background Pierre Robin sequence (Robin sequence) is defined as the triad of micrognathia, glossoptosis, and airway obstruction. It is frequently associated with palatal clefting. In recent years, increased interest in speech outcomes of cleft patients diagnosed with Robin sequence has been shown. Methods Speech outcomes of cleft patients with Robin sequence were assessed at age 5 in comparison with a cleft palate-only cohort. Speech parameters were evaluated according to the Cleft Audit Protocol for Speech-Augmented and analyzed using the National Audit Standards for Speech (United Kingdom). All patients were treated in the same institution during the same period (2005 to 2012). Subjects who needed nasopharyngeal airway support and those whose airway was managed by positioning only were eligible. Results Fifty-one cleft patients diagnosed with Robin sequence were included in this study. Outcomes were compared to those of 128 nonsyndromic cleft palate-only patients.Patients with Robin sequence were shown to present with a significantly higher rate of cleft speech characteristics in comparison to the reference cohort (p = 0.001). Furthermore, it was shown that Robin sequence is associated with a significantly higher rate of secondary speech surgery for velopharyngeal dysfunction before the age of 5 (p = 0.016). Robin sequence patients with a nasopharyngeal airway presented with a higher rate of cleft speech characteristics compared to Robin sequence patients managed with positioning only. Conclusion Cleft patients with Robin sequence are more likely to need further surgery to correct velopharyngeal dysfunction before the age of 5 and are more prone to present with cleft speech characteristics at the age of 5. Clinical question/level of evidence Risk, II.

Invasive insects pose an increasing risk to global agriculture, environmental stability, and public health. Giant pine scale (GPS), Marchalina hellenica Gennadius (Hemiptera: Marchalinidae), is a phloem feeding scale insect endemic to the Eastern Mediterranean Basin, where it primarily feeds on Pinus halepensis and other Pinaceae. In 2014, GPS was detected in the southeast of Melbourne, Victoria, Australia, infesting the novel host Pinus radiata. An eradication program was unsuccessful, and with this insect now established within the state, containment and management efforts are underway to stop its spread; however, there remains a need to understand the insect’s phenology and behaviour in Australia to better inform control efforts. We documented the annual life cycle and seasonal fluctuations in activity of GPS in Australia over a 32 month period at two contrasting field sites. Onset and duration of life stages were comparable to seasons in Mediterranean conspecifics, although the results imply the timing of GPS life stage progression is broadening or accelerating. GPS density was higher in Australia compared to Mediterranean reports, possibly due to the absence of key natural predators, such as the silver fly, Neoleucopis kartliana Tanasijtshuk (Diptera, Chamaemyiidae). Insect density and honeydew production in the Australian GPS population studied varied among locations and between generations. Although insect activity was well explained by climate, conditions recorded inside infested bark fissures often provided the weakest explanation of GPS activity. Our findings suggest that GPS activity is strongly influenced by climate, and this may in part be related to changes in host quality. An improved understanding of how our changing climate is influencing the phenology of phloem feeding insects such as GPS will help with predictions as to where these insects are likely to flourish and assist with management programs for pest species.

Trade-offs between photosynthesis and the costs of resource capture inform economic strategies of plants across environmental gradients and result in predictable variation in leaf traits. However, understudied functional groups like hemiparasites that involve dramatically different strategies for resource capture may have traits that deviate from expectations. We measured leaf traits related to gas exchange in mistletoes and their eucalypt hosts along a climatic gradient in relative moisture supply, measured as the ratio of precipitation to pan evaporation (P/Ep), in Victoria, Australia. We compared traits for mistletoes vs. hosts as functions of relative moisture supply and examined trait-trait correlations in both groups. Eucalypt leaf traits responded strongly to decreasing P/Ep, consistent with economic theory. Leaf area and specific leaf area (SLA) decreased along the P/Ep gradient, while C:N ratio, leaf thickness, N per area, and δ13C all increased. Mistletoes responded overall less strongly to P/Ep based on multivariate analyses; individual traits sometimes shifted in parallel with those of hosts, but SLA, leaf thickness, and N per area showed no significant change across the gradient. For mistletoes, leaf thickness was inversely related to leaf dry matter content (LDMC), with no relationship between SLA and mass-based N. In mistletoes, reduced costs of transpiration (reflecting their lack of roots) and abundant succulent leaf tissue help account for observed differences from their eucalypt hosts. Trait-based analysis of atypical functional types such as mistletoes help refine hypotheses based on plant economics and specialized adaptations to resource limitation.

Adiabatic temperature rise is an important method for determining isocyanate conversion in polyurethane foam reactions as well as many other exothermic chemical reactions. Adiabatic temperature rise can be used in conjunction with change in height and mass measurements to gain understanding into the blowing and gelling reactions that occur during polyurethane foaming as well as give important information on cell morphology. FoamPi is an open-source Raspberry Pi device for monitoring polyurethane foaming reactions. The device effectively monitors temperature rise, change in foam height as well as changes in the mass during the reaction. Three Python scripts are also presented. The first logs raw data during the reaction. The second corrects temperature data such that it can be used in adiabatic temperature rise reactions for calculating isocyanate conversion; additionally this script reduces noise in all the data and removes erroneous readings. The final script extracts important information from the corrected data such as maximum temperature change and maximum height change as well as the time to reach these points. Commercial examples of such equipment exist however the price (£10000) of these equipment make these systems inaccessible for many research laboratories. The FoamPi build presented is inexpensive (£350) and test examples are shown here to indicate the reproducibility of results as well as precision of the FoamPi.

The intensity of extreme heat and drought events has drastically risen in recent decades and will likely continue throughout the century. Northern forests have already seen increases in tree mortality and a lack of new recruitment, which is partially attributed to these extreme events. Boreal species, such as paper birch (Betula papyrifera) and white spruce (Picea glauca), appear to be more sensitive to these changes than lower-latitude species. Our objectives were to investigate the effects of repeated heatwaves and drought on young paper birch and white spruce trees by examining (i) responses in leaf gas exchange and plant growth and (ii) thermal acclimation of photosynthetic and respiratory traits to compare ecophysiological responses of two co-occurring, yet functionally dissimilar species. To address these objectives, we subjected greenhouse-grown seedlings to two consecutive summers of three 8-day long, +10 °C heatwaves in elevated atmospheric CO2 conditions with and without water restriction. The data show that heatwave stress reduced net photosynthesis, stomatal conductance and growth—more severely so when combined with drought. Acclimation of both photosynthesis and respiration did not occur in either species. The combination of heat and drought stress had a similar total effect on both species, but each species adjusted traits differently to the combined stress. Birch experienced greater declines in gas exchange across both years and showed moderate respiratory but not photosynthetic acclimation to heatwaves. In spruce, heatwave stress reduced the increase in basal area in both experimental years and had a minor effect on photosynthetic acclimation. The data suggest these species lack the ability to physiologically adjust to extreme heat events, which may limit their future distributions, thereby altering the composition of boreal forests.

How species coexist despite competing for the same resources that are in limited supply is central to our understanding of the controls on biodiversity1,2. Resource partitioning may facilitate coexistence, as co-occurring species use different sources of the same limiting resource3,4. In plant communities, however, direct evidence for partitioning of the commonly limiting nutrient, phosphorus (P), has remained scarce due to the challenges of quantifying P acquisition from its different chemical forms present in soil5. To address this, we used 33P to directly trace P uptake from DNA, orthophosphate and calcium phosphate into monocultures and mixed communities of plants growing in grassland soil. We show that co-occurring plants acquire P from these important organic and mineral sources in different proportions, and that differences in P source use are consistent with the species’ root adaptations for P acquisition. Furthermore, the net benefit arising from niche plasticity (the gain in P uptake for a species in a mixed community compared to monoculture) correlates with species abundance in the wild, suggesting that niche plasticity for P is a driver of community structure. This evidence for P resource partitioning and niche plasticity may explain the high levels of biodiversity frequently found in P-limited ecosystems worldwide6,7. In plant communities, co-occurring species compete for resources such as mineral nutrients under limited supply. Here, the researchers found that a major mineral nutrient, phosphorus, was taken up by co-occurring plants in species-specific proportions of different forms, which may drive the development of community biodiversity.

Configuring databases for efficient querying is a complex task, often carried out by a database administrator. Solving the problem of building indexes that truly optimize database access requires a substantial amount of database and domain knowledge, the lack of which often results in wasted space and memory for irrelevant indexes, possibly jeopardizing database performance for querying and certainly degrading performance for updating. In this paper, we develop the SmartIX architecture to solve the problem of automatically indexing a database by using reinforcement learning to optimize queries by indexing data throughout the lifetime of a database. We train and evaluate SmartIX performance using TPC-H, a standard, and scalable database benchmark. Our empirical evaluation shows that SmartIX converges to indexing configurations with superior performance compared to standard baselines we define and other reinforcement learning methods used in related work.

application/pdf, • Background and Aims An individual plant consists of different-sized shoots, each of which consists of different-sized leaves. To predict plant-level physiological responses from the responses of individual leaves, modelling this within-shoot leaf size variation is necessary. Within-plant leaf trait variation has been well investi-gated in canopy photosynthesis models but less so in plant allometry. Therefore, integration of these two different approaches is needed. • Methods We focused on an established leaf-level relationship that the area of an individual leaf lamina is pro - portional to the product of its length and width. The geometric interpretation of this equation is that different-sized leaf laminas from a single species share the same basic form. Based on this shared basic form, we synthesized a new length-times-width equation predicting total shoot leaf area from the collective dimensions of leaves that comprise a shoot. Furthermore, we showed that several previously established empirical relationships, including the allometric relationships between total shoot leaf area, maximum individual leaf length within the shoot and total leaf number of the shoot, can be unified under the same geometric argument. We tested the model predic - tions using five species, all of which have simple leaves, selected from diverse taxa (Magnoliids, monocots and eudicots) and from different growth forms (trees, erect herbs and rosette herbs). • Key Results For all five species, the length-times-width equation explained within-species variation of total leaf area of a shoot with high accuracy ( R2 > 0.994). These strong relationships existed despite leaf dimensions scaling very differently between species. We also found good support for all derived predictions from the model (R2 > 0.85). • Conclusions Our model can be incorporated to improve previous models of allometry that do not consider within-shoot size variation of individual leaves, providing a cross-scale linkage between individual leaf-size vari-ation and shoot-size variation.

Ants utilise age- and caste-based division of labour, providing an opportunity to investigate behavioural and neural plasticity. Newly eclosed workers perform tasks, such as nursing, and initiate foraging as they mature. Alate males only search for mates and do so exclusively on the wing. In worker ants, age and initial light exposure induce neural changes to the mushroom bodies, higher-order sensory processing regions. However, synaptic neuroplasticity has not been directly linked to the behavioural transition into forager life. In hymenopterans, males demonstrate neuroplasticity associated with initial flights or mating, yet it is unknown how age affects neural circuitry. I documented the navigational behaviour of naïve ants as they exited the nest on consecutive trips. I then compared the structure and organisation of olfactory and visual neuropils within the mushroom bodies with behaviour and foraging experience. Ants leaving the nest for the first time carry out learning walks during which they regularly look back towards the nest. As animals gained experience, their path towards the feeder became increasingly direct. I found no evidence of neuroplasticity among workers with different experience levels. Comparing males that were 2 and 11 days old, I found that the volume and number of synaptic profiles increased in the visual neuropils of mushroom bodies. However, a similar comparison in workers revealed no such differences. I discuss how these differences in neuroplasticity in each caste have evolved to suit their respective lifestyles and ecologies.

Conjugative plasmids play an important role in bacterial evolution by transferring niche-adaptive traits between lineages, thus driving adaptation and genome diversification. It is increasingly clear, however, that in addition to this evolutionary role, plasmids also manipulate the expression of a broad range of bacterial phenotypes. In this review, we argue that the effects that plasmids have on the expression of bacterial phenotypes may often represent plasmid adaptations, rather than mere deleterious side effects. We begin by summarizing findings from untargeted omics analyses, which give a picture of the global effects of plasmid acquisition on host cells. Thereafter, because many plasmids are capable of both vertical and horizontal transmission, we distinguish plasmid-mediated phenotypic effects into two main classes based upon their potential fitness benefit to plasmids: (i) those that promote the competitiveness of the host cell in a given niche and thereby increase plasmid vertical transmission, and (ii) those that promote plasmid conjugation and thereby increase plasmid horizontal transmission. Far from being mere vehicles for gene exchange, we propose that plasmids often act as sophisticated genetic parasites capable of manipulating their bacterial hosts for their own benefit. This article is part of the theme issue ‘The secret lives of microbial mobile genetic elements’.

Problem: Brain imaging studies of mental health and neurodevelopmental disorders have recently included machine learning approaches to identify patients based solely on their brain activation. The goal is to identify brain-related features that generalize from smaller samples of data to larger ones; in the case of neurodevelopmental disorders, finding these patterns can help understand differences in brain function and development that underpin early signs of risk for developmental dyslexia. The success of machine learning classification algorithms on neurofunctional data has been limited to typically homogeneous data sets of few dozens of participants. More recently, larger brain imaging data sets have allowed for deep learning techniques to classify brain states and clinical groups solely from neurofunctional features. Indeed, deep learning techniques can provide helpful tools for classification in healthcare applications, including classification of structural 3D brain images. The adoption of deep learning approaches allows for incremental improvements in classification performance of larger functional brain imaging data sets, but still lacks diagnostic insights about the underlying brain mechanisms associated with disorders; moreover, a related challenge involves providing more clinically-relevant explanations from the neural features that inform classification.Methods: We target this challenge by leveraging two network visualization techniques in convolutional neural network layers responsible for learning high-level features. Using such techniques, we are able to provide meaningful images for expert-backed insights into the condition being classified. We address this challenge using a dataset that includes children diagnosed with developmental dyslexia, and typical reader children.Results: Our results show accurate classification of developmental dyslexia (94.8%) from the brain imaging alone, while providing automatic visualizations of the features involved that match contemporary neuroscientific knowledge (brain regions involved in the reading process for the dyslexic reader group and brain regions associated with strategic control and attention processes for the typical reader group).Conclusions: Our visual explanations of deep learning models turn the accurate yet opaque conclusions from the models into evidence to the condition being studied.

Gentrification has long been a contentious issue which has prompted debate among scholars due to variations in its location, timing, context and types of measurements used. Therefore, it is worth seeking a simple and effective approach to measure the processes of gentrification, which enables comparative studies to be conducted across different cities around the world. Using six sets of thematic data from 2001 and 2011 at the neighbourhood level, this study proposes five types of gentrification and displacement by using Chapple and Zuk’s theoretical framework. London was selected as a case study. The results show that gentrification was sweeping in many ways during the 2000s in London, particularly in Inner East London. Some areas in North West London are identified as vulnerable neighbourhoods at risk of displacement and gentrification. Furthermore, it was found that most of the neighbourhoods experiencing ongoing displacement are concentrated in Outer London and Inner South London. The typology provides a useful starting point for planners and policymakers to gain deeper insights into the progress of gentrification in London. Additionally, this work can serve as an example to illustrate the potential for using similar types of open source code and census data to estimate the degree of gentrification in other cities.

International audience; The vast majority of measurements in the field of plant hydraulics have been on small-diameter branches from woody species. These measurements have provided considerable insight into plant functioning, but our understanding of plant physiology and ecology would benefit from a broader view, because branch hydraulic properties are influenced by many factors. Here, we discuss the influence that other components of the hydraulic network have on branch vulnerability to embolism propagation. We also modelled the impact of changes in the ratio of root-to-leaf areas and soil texture on vulnerability to hydraulic failure along the soil-to-leaf continuum and showed that hydraulic function is better maintained through changes in root vulnerability and root-to-leaf area ratio than in branch vulnerability. Differences among species in the stringency with which they regulate leaf water potential and in reliance on stored water to buffer changes in water potential also affect the need to construct embolism resistant branches. Many approaches, such as measurements on fine roots, small individuals, combining sap flow and psychrometry techniques, and modelling efforts, could vastly improve our understanding of whole-plant hydraulic functioning. A better understanding of how traits are coordinated across the whole plant will improve predictions for plant function under future climate conditions.

Nutrients are heterogeneously distributed in the soil environment. Plants have evolved a variety of mechanisms to maximise their ability to compete for limited resources, with differential root growth considered among the more important mechanisms. Despite the significant costs of root growth, little data is available regarding carbon (C) allocation to roots growing in heterogeneous conditions. Here, we investigate the allocation of recently assimilated C in Poa annua plants growing in uniform or heterogeneous nutrient conditions. In the first experiment we grew plants in split-root boxes, providing N either equally between the two chambers (0.5 mg/0.5 mg, 8 mg/8 mg) or with one side receiving more N (0.5 mg/8 mg, 8 mg/0.5 mg), and quantified C allocation and N uptake using 13CO2 and K15NO3. Where N was supplied equally to the two chambers, C was allocated equally to the roots irrespective of the total N supply. However, the 13C label was preferentially allocated (60:40) to high-N roots in the unequal treatments. N uptake was a function of local supply and was not affected by N supply to the roots in the other chamber. C allocation had no discernible effect on N uptake. In the second experiment, we tested whether differential N supply would lead to increased root growth in the high-N side. In this experiment, equal amounts of N were supplied to all plants as ammonium, with half receiving an equal distribution to the two root chambers (50/50), while the other half received an unequal supply (94/6). While no difference in root growth was noted in 50/50 plants, a 60:40 mass allocation was noted from day six onwards in plants receiving the 94/6 N supply. Despite increased root growth in the high-N side, the plants receiving the 94/6 treatment could not achieve the same shoot mass or N concentration as the 50/50 plants. No difference in total C allocation to the roots between treatments was noted in the first experiment, and no difference in total root mass between treatments was found in the second experiment, suggesting that root C supply was source-limited, while allocation to specific roots was strongly influenced by sink strength. Differential C allocation appears to be an important pre-requisite for increased root growth in N-rich patches.

Vulnerability-to-cavitation curves (VCs) can vary within a tree crown in relation to position or branch age. We tested the hypothesis that VC variation can arise from differential susceptibility to the number of diurnal sap pressure cycles experienced. We designed a method to distinguish between effects of cycling vs exposure time to negative pressure, and tested the influence of sap pressure cycles on cavitation vulnerability between upper and lower branches in Acer negundo L. trees using static and flow centrifuge, and air-injection methods. Branches from the upper crown had greater hydraulic conductivity and were more resistant to cavitation than branches from the lower crown. Upper branches also showed little change after exposure to 10 or 20 pressure cycles between -0.5 MPa and -2.0 MPa. Lower branches, however, showed a marked increase in vulnerability to cavitation after pressure-cycling. This result suggests that 'cavitation fatigue' can occur without the actual induction (and reversal) of cavitation as documented previously, but simply from the cycling of pressures in the sub-cavitation range. This 'pressure fatigue' may explain age-related shifts in VCs that could eventually induce dieback in suppressed branches or trees. Pressure fatigue may help explain developmental variation in hydraulic capacity of branches within individuals.

Black carbon (BC), the product of the incomplete combustion of fossil fuels and biomass, is ubiquitous in soils globally. Although BC is a major soil carbon pool, its effects on the global carbon cycle have not yet been resolved. It is deemed to represent a large stable pool in soils turning over on geological timescales, but research suggests it can alter soil biogeochemical cycling including that of ecosystem-derived organic carbon. Here, we established two soil microcosm chamber experiments: experiment one added 13C organic carbon to soil with and without added BC (soot and biochar) to investigate whether it suppressed organic carbon mineralisation; experiment two added 13C BC (soot) to soil to establish whether it is mineralised in soil over a short timescale. Gases were sampled over six-months and analysed using isotope ratio mass spectrometry. In experiment one we found that the efflux of 13C organic carbon from the soil decreased over time, but the addition of soot to soil significantly reduced the mineralisation of organic carbon from 32% of the total supplied without soot to 14% of the total supplied with soot. In contrast, there was not a significant difference after the addition of biochar in the flux of δ 13CO2 from the organic carbon added to the soil. In experiment two, we found that the efflux 13C from soil with added 13C labelled soot significantly differed from the control, but this efflux declined over time. There was a cumulative loss of 0.17% 13C from soot over the experiment.These experimental results represent a step-change in understanding the influence of BC continuum on carbon dynamics, which has major consequences for the way we measure, monitor and manage soils for carbon storage and sequestration in the future.

Partner-switching plays an important role in the evolution of symbiosis, enabling local adaptation and recovery from the breakdown of symbiosis. Because of intergenomic epistasis, partner-switched symbioses may possess novel combinations of phenotypes but may also exhibit low fitness due to their lack of recent coevolutionary history. Here, we examine the structure and mechanisms of intergenomic epistasis in the Paramecium-Chlorella symbiosis and test if compensatory evolution can rescue initially low fitness partner-switched symbioses. Using partner-switch experiments coupled with metabolomics we show evidence for intergenomic epistasis wherein low fitness arose from mismatched photoprotection traits and the resulting light stress experienced by non-native symbionts when in high light environments. Experimental evolution under high light conditions revealed that an initially low fitness partner-switched non-native host-symbiont pairing rapidly adapted, gaining fitness equivalent to the native host symbiont pairing in less than 50 host generations. Compensatory evolution took two alternative routes: Either, hosts evolved higher symbiont loads to mitigate for their new algal symbiont’s poor performance, or the algal symbionts themselves evolved higher investment in photosynthesis and photoprotective traits to better mitigate light stress. These findings suggest that partner-switching combined with rapid compensatory evolution will enable the recovery and local adaptation of symbioses in response to changing environments.Significance statementSymbiosis enables the formation of new organisms through the merger of once independent species. Through symbiosis, species can acquire new functions, driving evolutionary innovation and underpinning important ecosystem processes. Symbioses that breakdown due to changing environmental conditions can reform by acquiring new symbionts in a process called partner-switching but may exhibit low fitness due to their lack of coadaptation. Using a microbial symbiosis between the single-celled eukaryote Paramecium and the green alga Chlorella we show that low fitness in partner-switched host-symbiont pairings arises from mismatched photoprotection traits. However, such low fitness partner-switched pairings can be rapidly rescued by adaptive evolution, regaining high fitness in less than 50 host generations. Partner-switching coupled with rapid compensatory evolution can enable symbioses to recover from breakdown.

Covid-19 related restrictions have forced public transport services to operate with less capacity. In response, trips are channelled to walking and cycling. We use shortest-path analysis to identify all street-level connections between all rail and underground stations in inner London. We are able to identify the critical pathways which show a long tail distribution and a radial/cellular spatial pattern. We visually compare this network with the existing cycling network and explore two scenarios of street interventions in 8 critical pathways using streetspace cross-section analysis. The methods presented here can offer valuable analytical capacity for developing new cycling and walking schemes and designing place-based streets that are more appropriate to control virus propagation.

Compact city and transit-oriented development aims of integrating public transport networks with high density mixed-use development around stations and urban centers have been prominent policies for improving urban transport sustainability in many cities around the world for several decades. Although these policies have been in many respects successful for planning at the city level, there are increasing challenges in how residential housing markets have responded to thriving inner-city areas, with poorer groups potentially priced-out of inner cities to more peripheral areas with more limited public transport and active travel opportunities. Typically, suburban and ex-urban areas are car-dependent, even in cities known for extensive public transport networks. With this contextual background, this chapter examines residential socioeconomic change in Greater London, analyzing how lower income groups are increasingly being pushed to areas of poorer accessibility in Outer London because of high residential prices and housing shortages. Potential policies are reviewed to address this demographic segregation, including a major increase in affordable housing provision, and significant investment in orbital public transport services, to attempt to alter the present highly centralized pattern of regional public transport accessibility.

Photosynthetic sensitivity to drought is a fundamental constraint on land-plant evolution and ecosystem function. However, little is known about how the sensitivity of photosynthesis to nonstomatal limitations varies among species in the context of phylogenetic relationships. Using saplings of 10 Eucalyptus species, we measured maximum CO2 -saturated photosynthesis using A-ci curves at several different leaf water potentials (ψleaf ) to quantify mesophyll photosynthetic sensitivity to ψleaf (MPS), a measure of how rapidly nonstomatal limitations to carbon uptake increase with declining ψleaf . MPS was compared to the macroclimatic moisture availability of the species' native habitats, while accounting for phylogenetic relationships. We found that species native to mesic habitats have greater MPS but higher maximum photosynthetic rates during non-water-stressed conditions, revealing a trade-off between maximum photosynthesis and drought sensitivity. Species with lower turgor loss points have lower MPS, indicating coordination among photosynthetic and water-relations traits. By accounting for phylogenetic relationships among closely related species, we provide the first compelling evidence that MPS in Eucalyptus evolved in an adaptive fashion with climatically determined moisture availability, opening the way for further study of this poorly explored dimension of plant adaptation to drought.

Modern feed quality sorghum grain has been bred to reduce anti-nutrients, most conspicuously condensed tannins, but its inclusion in the diets of monogastric animals can still result in variable performance that is only partially understood. Sorghum grain contains several negative intrinsic factors, including non-tannin phenolics and polyphenols, phytate, and kafirin protein, which may be responsible for these muted feed performances. To better understand the non-tannin phenolic and polyphenolic metabolites that may have negative effects on nutritional parameters, the chemical composition of sorghum grain polyphenol extracts from three commercial varieties (MR-Buster, Cracka, and Liberty) was determined through the use of an under-studied, alternative analytical approach involving Fourier-transform infrared (FT-IR) spectroscopy and direct ionization mass spectrometry. Supervised analyses and interrogation of the data contributing to variation resulted in the identification of a variety of metabolites, including established polyphenols, lignin-like anti-nutrients, and complex sugars, as well as high levels of fatty acids which could contribute to nutritional variation and underperformance in monogastrics. FT-IR and mass spectrometry could both discriminate among the different sorghum varieties indicating that FT-IR, rather than more sophisticated chromatographic and mass spectrometric methods, could be incorporated into quality control applications.

Trade-offs between photosynthesis and the costs of resource capture inform economic strategies of plants across environmental gradients and result in predictable variation in leaf traits. However, understudied functional groups like hemiparasites that involve dramatically different strategies for resource capture may have traits that deviate from expectations. We measured leaf traits related to gas exchange in mistletoes and their eucalypt hosts along a climatic gradient in relative moisture supply, measured as the ratio of precipitation to pan evaporation (P/E

Brain imaging of mental health, neurodevelopmental and learning disorders has coupled with machine learning to identify patients based only on their brain activation, and ultimately identify features that generalize from smaller samples of data to larger ones. However, the success of machine learning classification algorithms on neurofunctional data has been limited to more homogeneous data sets of dozens of participants. More recently, larger brain imaging data sets have allowed for the application of deep learning techniques to classify brain states and clinical groups solely from neurofunctional features. Deep learning techniques provide helpful tools for classification in healthcare applications, including classification of structural 3D brain images. Recent approaches improved classification performance of larger functional brain imaging data sets, but they fail to provide diagnostic insights about the underlying conditions or provide an explanation from the neural features that informed the classification. We address this challenge by leveraging a number of network visualization techniques to show that, using such techniques in convolutional neural network layers responsible for learning high-level features, we are able to provide meaningful images for expert-backed insights into the condition being classified. Our results show not only accurate classification of developmental dyslexia from the brain imaging alone, but also provide automatic visualizations of the features involved that match contemporary neuroscientific knowledge, indicating that the visual explanations do help in unveiling the neurological bases of the disorder being classified., Comment: 19 pages, 7 Figures, submitted to Journal of Visualization

Soils hold three quarters of the total organic carbon (OC) stock in terrestrial ecosystems and yet we fundamentally lack detailed mechanistic understanding of the turnover of major soil OC pools. Black carbon (BC), the product of the incomplete combustion of fossil fuels and biomass, is ubiquitous in soils globally. Although BC is a major soil carbon pool, its effects on the global carbon cycle have not yet been resolved. Soil BC represents a large stable carbon pool turning over on geological timescales, but research suggests it can alter soil biogeochemical cycling including that of soil OC. Here, we established two soil microcosm experiments: experiment one added 13C OC to soil with and without added BC (soot or biochar) to investigate whether it suppresses OC mineralisation; experiment two added 13C BC (soot) to soil to establish whether it is mineralised in soil over a short timescale. Gases were sampled over six-months and analysed using isotope ratio mass spectrometry. In experiment one we found that the efflux of 13C OC from soil decreased over time, but the addition of soot to soil significantly reduced the mineralisation of OC from 32% of the total supplied without soot to 14% of the total supplied with soot. In contrast, there was not a significant difference after the addition of biochar in the flux of 13C from the OC added to the soil. In experiment two, we found that the efflux 13C from soil with added 13C soot significantly differed from the control, but this efflux declined over time. There was a cumulative loss of 0.17% 13C from soot over the experiment. These experimental results represent a step-change in understanding the influence of BC continuum on carbon dynamics, which has major consequences for the way we monitor and manage soils for carbon sequestration in future.

Polycentric urban development is gaining momentum in both scholarly research and real-life practice. This brings new demand for planning support systems to simulate and analyse the urban spatial structure in terms of polycentricity under various urban policy scenarios. With the help of emerging urban data, urban simulation techniques, and network science, this study proposes a workflow to simulate the urban spatial structure with spatial interaction as a part of the planning support system. Using Singapore as a case study, this study has explored the resulting urban spatial structure with four employment distribution strategies. The results suggest that planning practices impact urban spatial structure and its spatial interaction by redistributing urban morphological elements, such as employment in this study. Also, our results show that the physical urban spatial structure and spatial interaction are closely related. These results reinforce the role of urban planning practice to achieve a more sustainable and coherent urban built environment. Through this empirical evidence, our workflow exemplifies the potential of the planning support system to help urban planners and governments understand their urban policy regarding urban polycentricity.

Species' differences in the stringency of stomatal control of plant water potential represent a continuum of isohydric to anisohydric behaviours. However, little is known about how quasi-steady-state stomatal regulation of water potential may relate to dynamic behaviour of stomata and photosynthetic gas exchange in species operating at different positions along this continuum. Here, we evaluated kinetics of light-induced stomatal opening, activation of photosynthesis and features of quasi-steady-state photosynthetic gas exchange in 10 woody species selected to represent different degrees of anisohydry. Based on a previously developed proxy for the degree of anisohydry, species' leaf water potentials at turgor loss, we found consistent trends in photosynthetic gas exchange traits across a spectrum of isohydry to anisohydry. More anisohydric species had faster kinetics of stomatal opening and activation of photosynthesis, and these kinetics were closely coordinated within species. Quasi-steady-state stomatal conductance and measures of photosynthetic capacity and performance were also greater in more anisohydric species. Intrinsic water-use efficiency estimated from leaf gas exchange and stable carbon isotope ratios was lowest in the most anisohydric species. In comparisons between gas exchange traits, species rankings were highly consistent, leading to species-independent scaling relationships over the range of isohydry to anisohydry observed.

Twig cross-sectional area and the surface area of leaves borne on it are expected to be isometrically correlated across species (Corner's rules). However, how stable this relationship remains in time is not known. We studied inter- and intraspecific twig leaf area-cross-sectional area (la-cs) and other scaling relationships, including the leaf-shoot mass (lm-sm) scaling relationship, across a complete growing season. We also examined the influence of plant height, deciduousness and the inclusion of reproductive buds on the stability of the scaling relationships, and we discuss results from a functional perspective.We collected weekly current-year twigs of six Patagonian woody species that differed in growth form and foliar habit. We also used prominent inflorescences from Embothrium coccineum (Proteaceae) to assess whether reproductive buds alter the la-cs isometric relationship. Mixed effects models were fitted to obtain parameter estimates and to test whether interaction terms were non-significant (invariant) for the scaling relationships.The slope of the la-cs scaling relationship remained invariant across the growing season. Two species showed contrasting and disproportional (allometric) la-cs scaling relationships (slope ≠ 1). Scaling relationships varied significantly across growth form and foliar habit. The lm-sm scaling relationship differed between reproductive- and vegetative-origin twigs in E. coccineum, which was explained by a significantly lower leaf mass per area in the former.Although phenology during the growing season appeared not to change leaf-shoot scaling relationships across species, we show that scaling relationships departed from the general trend of isometry as a result of within-species variation, growth form, foliar habit and the type of twig. The identification of these functional factors helps to understand variation in the general trend of Corner's rules.

Background and aims Corner's rule states that thicker twigs bear larger leaves. The exact nature of this relationship and why it should occur has been the subject of numerous studies. It is obvious that thicker twigs should support greater total leaf area ([Formula: see text]) for hydraulical and mechanical reasons. But it is not obvious why mean leaf size ([Formula: see text]) should scale positively with [Formula: see text] We asked what this scaling relationship is within species and how variable it is across species. We then developed a model to explain why these relationships exist. Methods To minimize potential sources of variability, we compared twig properties from six co-occurring and functionally similar species: Acer grandidentatum, Amelanchier alnifolia, Betula occidentalis, Cornus sericea, Populus fremontii and Symphoricarpos oreophilus We modelled the economics of leaf display, weighing the benefit from light absorption against the cost of leaf tissue, to predict the optimal [Formula: see text] combinations under different canopy openings. Key results We observed a common [Formula: see text] by [Formula: see text] exponent of 0.6, meaning that [Formula: see text]and leaf number on twigs increased in a specific coordination. Common scaling exponents were not supported for relationships between any other measured twig properties. The model consistently predicted positive [Formula: see text] by [Formula: see text] scaling when twigs optimally filled canopy openings. The observed 0·6 exponent was predicted when self-shading decreased with larger canopy opening. Conclusions Our results suggest Corner's rule may be better understood when recast as positive [Formula: see text] by [Formula: see text] scaling. Our model provides a tentative explanation of observed [Formula: see text] by [Formula: see text] scaling and suggests different scaling may exist in different environments.

Here, we summarize studies on the effects of elevated [CO2 ] (CO2e ) on the structure and function of plant hydraulic architecture and explore the implications of those changes using a model. Changes in conduit diameter and hydraulic conductance due to CO2e vary among species. Ring-porous species tend towards an increase in conduit size and consequently conductivity. The effect in diffuse-porous species is much more limited. In conifers, the results are mixed, some species show minor changes in xylem structure, while other studies found increases in tracheid density and diameter. Non-woody plants generally exhibited the reverse pattern with narrower conduits and lower hydraulic conductivity under CO2e . Further, changes in drought-resistance traits suggest that non-woody plants were the most affected by CO2e , which may permit them to better resist drought-induced embolism under future conditions. Due to their complexity, acclimation in hydraulic traits in response to CO2e is difficult to interpret when relying solely on measurements. When we examined how the observed tissues-specific trends might alter plant function, our modelling results suggest that these hydraulic changes would lead to reduced conductance and more frequent drought stress in trees that develop under CO2e with a more pronounced effect in isohydric than in anisohydric species.

How species coexist despite competing for the same resources that are in limited supply is central to our understanding of the controls on biodiversity

Evolutionary theory suggests that the conditions required for the establishment of mutualistic symbioses through mutualism alone are highly restrictive, often requiring the evolution of complex stabilising mechanisms. Exploitation, whereby initially the host benefits at the expense of its symbiotic partner and mutual benefits evolve subsequently through trade-offs, offers an arguably simpler route to the establishment of mutualistic symbiosis. In this review, we discuss the theoretical and experimental evidence supporting a role for host exploitation in the establishment and evolution of mutualistic microbial symbioses, including data from both extant and experimentally evolved symbioses. We conclude that exploitation rather than mutualism may often explain the origin of mutualistic microbial symbioses., The authors review the theoretical and experimental evidence supporting exploitation as an alternative route to the evolution of mutualistic symbioses.

‘Babel’ is a paradoxical word. It is a name that was given to a city at the moment of its abandonment, and to a tower at the moment of its failure to be built. It signifies the variety of languages and yet is itself to be found unchanged in very many languages of the world. People can understand the word ‘Babel’; but what it means is the disintegration of understanding. Its meaning is the confusion of meaning.

The degree of plant iso/anisohydry, a widely used framework for classifying species-specific hydraulic strategies, integrates multiple components of the whole-plant hydraulic pathway. However, little is known about how it associates with coordination of functional and structural traits within and across different organs. We examined stem and leaf hydraulic capacitance and conductivity/conductance, stem xylem anatomical features, stomatal regulation of daily minimum leaf and stem water potential (Ψ), and the kinetics of stomatal responses to vapour pressure deficit (VPD) in six diverse woody species differing markedly in their degree of iso/anisohydry. At the stem level, more anisohydric species had higher wood density and lower native capacitance and conductivity. Like stems, leaves of more anisohydric species had lower hydraulic conductance; however, unlike stems, their leaves had higher native capacitance at their daily minimum values of leaf Ψ. Moreover, rates of VPD-induced stomatal closure were related to intrinsic rather than native leaf capacitance and were not associated with species' degree of iso/anisohydry. Our results suggest a trade-off between hydraulic storage and efficiency in the leaf, but a coordination between hydraulic storage and efficiency in the stem along a spectrum of plant iso/anisohydry.

Investigations were undertaken in the context of the potential environmental impact of Carbon Capture and Storage (CCS) transportation in the form of a hypothetical leak of extreme levels of CO2 into the soil environment and subsequent effects on plant physiology. Laboratory studies using purpose built soil chambers, separating and isolating the soil and aerial environments, were used to introduce high levels of CO2 gas exclusively into the rhizosphere. CO2 concentrations greater than 32% in the isolated soil environment revealed a previously unknown whole plant stomatal response. Time course measurements of stomatal conductance, leaf temperature and leaf abscisic acid show strong coupling between all three variables over a specific period (3 hrs following CO2 gassing) occurring as a result of CO2-specific detection by roots. The coupling of gs and ABA subsequently breaks down resulting in a rapid and complete loss of turgor in the shoot. Root access to water is severely restricted as evidenced by the inability to counter turgor loss, however the plant regains some turgor over time. Recovery of full turgor is not achieved over the longer term. Results suggest an immediate perception and whole plant response as changes in measured parameters (leaf temperature, gs and ABA) occur in the shoot, but the response is solely due to detection of very high CO2 concentration at the root/soil interface which results in loss of stomatal regulation and disruption to control over water uptake.

This paper presents the first empirical data of soil temperature and soil moisture profiles with depth in the context of a buried Carbon Capture and Storage transportation pipeline operating at higher than ambient soil temperatures. In an experimental approach, soil temperature responses are non-linear and are raised and restricted to within 45cm of the subsurface heat source (hypothetical pipeline). A surface heat source is included to investigate interactions of natural seasonal surface heating of soils with subsurface heat. There is no interaction between subsurface and surface heat sources in the experimental system. Soil moisture profiles vary with soil type, with overall soil moisture losses of >10% over experimental time courses. Modelled soil temperature profiles show that the ability of soils to buffer thermal movement from depths up to 1.2m from the surface is currently inadequately represented. Measurements provide the first elementary data of soil temperature changes resulting from a subsurface heat source for more accurate modelling of soil/pipeline interactions.