Flame temperatures saturate with increasing dead material in Ulex europaeus, but flame duration, fuel consumption and overall flammability continue to increase

A key determinant of wildfire behaviour is the flammability of constituent plants. One plant trait that influences flammability is the retention of dead biomass, as the low moisture content of dead material means less energy is required to achieve combustion. However, the effect of the dead-to-live ratio of fuel on plant flammability has rarely been experimentally quantified. Here we examine the nature of the relationship between dead fuel accumulation and flammability in Ulex europaeus (common gorse). Shoots with varying proportions of dead material were ignited in a purpose-built plant-burner. Three components of flammability were measured: sustainability (flame duration), consumability (proportion burnt biomass) and combustibility (maximum temperature). While flame duration and proportion burnt biomass had a positive linear relationship with the proportion of dead material, the response of maximum temperature was positive but non-linear. All three flammability components were reduced to a single variable using principal components analysis; this had a non-linear relationship with the proportion of dead material. The response of maximum temperature to dead material plateaued at 39%. These findings have implications for the management of habitats invaded by gorse; to mitigate fire hazard associated with gorse, stands should be kept at a relatively young age when dead fuel is less prevalent

Imaging Neuroscience opening editorial

In this editorial we introduce a new non-profit open access journal, Imaging Neuroscience. In April 2023, editors of the journals NeuroImage and NeuroImage:Reports resigned, and a month later launched Imaging Neuroscience. NeuroImage had long been the leading journal in the field of neuroimaging. While the move to fully open access in 2020 represented a positive step toward modern academic practices, the publication fee was set to a level that the editors found unethical and unsustainable. The publisher of NeuroImage, Elsevier, was unwilling to reduce the fee after much discussion. This led us to launch Imaging Neuroscience with MIT Press, intended to replace NeuroImage as our field’s leading journal, but with greater control by the neuroimaging academic community over publication fees and adoption of modern and ethical publishing practices

Global enhancement of task‐irrelevant dimensions of attended objects

Experiments on the neural mechanisms of feature-based attention suggest that features are selected in parallel across the visual field (Treue & Trujillo, 1999). Moreover, feature-based attention spreads not only to the task-relevant feature in an unattended location, but also to a task-irrelevant feature when it is bound to the task-relevant feature in a task-irrelevant location (Sohn et al., 2005). We asked whether a similar mechanism is at work when the task-irrelevant feature is bound to the task-relevant feature at the attended location. Specifically, we asked whether attending to the color of moving dots in one visual field (VF) would influence the motion signal to colored moving dots in the other VF. Subjects attended to either red or cyan dots (both present in the upper right quadrant of the VF at the attended location and moving in opposite directions) and responded when the target dots dimmed. Critically, the color and motion of dots present in the upper left quadrant of the VF varied as a function of the attended dots such that they were either the same color/same direction, same color/opposite direction, opposite color/same direction, or opposite color/opposite direction as the attended dots. We found main effects of both color and direction in areas of ventral visual cortex responsive to the task-irrelevant location, such that BOLD activity was greater when either the dots’ color or direction were the same as the attended stimulus. We also found a main effect of direction in human MT/MST responsive to the task-irrelevant location, such that activity was greater when the dots in the task-irrelevant and task-relevant locations were moving in the same direction than when they were moving in opposite directions. These results support the theory that object-based attention leads to enhanced selection of all dimensions of the attended object, including task-irrelevant ones. Additionally, our findings suggest that this co-selection modulates the object’s dimensions independently throughout the visual field via a feature-based mechanism

Complex systems analysis of invasive species in heterogeneous environments

Given that so many ecosystems currently face major habitat change conducive to the rising global spread of invasive species, there is growing awareness of the need to adopt proactive management strategies. Among models most used to predict future changes in distribution of invasive species, few explicitly incorporate characteristic of the population dynamics at the invasion front and the spatial heterogeneity of the environment. In particular, the influence of landscape composition and configuration on population dynamics and ecosystem susceptibility to invasion, remain dependent on broad generalization. The purpose of this study was to investigate how biological characteristics of invasive species interact with the structure of the landscape, to determine establishment and spread success. Critical to this research was the development of a unique spatially-explicit model that allowed for a systemic investigation of the impact of landscape structure on population dynamics of a species. The modelling framework has three components,1) a spatially-explicit, individual-based dispersal simulation framework, 2) a landscape generator allowing independent change in the composition and configuration of landscape components, and, 3) appropriate landscape measures that establish a quantitative relationship between demography, dispersal and the environment. The framework allowed a shift in focus from an individual species, to a more general approach where the pattern of invasion over multiple species and landscape scenarios were used to infer key drivers of invasion. To identify appropriate landscape measures for this research, a multi-scale analysis of widely used landscape metrics was carried out. That analysis highlighted that landscape metrics are sensitive to complex interactions between the intrinsic characteristics of a landscape, and scale-dependent factors, making it difficult to isolate landscape pattern driven effects from the effects of changing spatial scale. As a solution, the self-organising map (SOM) clustering approach is proposed as an efficient way to disentangle the relationships among landscape metrics and spatial scale when accurate characterization of landscape pattern is a key input in spatially explicit ecological models. The investigation of the effect of landscape structure on the establishment and spread of invasive species showed that both population density and rate of spread are affected in significant ways, and sometimes interactively, by landscape based components such as, suitable habitat amount, habitat patch aggregation, core area, edge density and habitat shape complexity. A key result of this research suggests that areas that are vulnerable to invasion can be better predicted by quantifying the elements of the landscape that significantly influence the density and spread of a species. However, the identification of an optimal set of landscape metrics for a species will require case specific study as clearly different species will respond to landscape structure in different ways. This research also demonstrated that dominant processes shaping population density and spread of invasive species can be identified and prioritized, as well as those of secondary importance. Variables representing an Allee effect, the intrinsic rate of increase and propagule pressure were found to be the three most influential on both density and spread over multiple invasive species scenarios. The frequency of long-distance dispersal events, in combination with measures of suitable habitat amount and habitat aggregation, was found to be a better indicators of population dynamics than the intrinsic abilities of a species to disperse in fragmented landscapes. This research has shown that the presence of an Allee effect leads to a balance between the effectiveness of spread and invasion success. Spread is maximized at an intermediate dispersal rate and inhibited at both low and high rates. The configuration and composition of the landscape, by either increasing or mitigating or the dispersal abilities of a species, can lead to a rate of spread under a dispersal threshold for which density and spread is at the highest. This research highlights how complex interactions between propagule pressure, species traits and habitat characteristics can determine patterns of invasion across fragmented landscapes. Successful management of invasive species, particularly for prioritisation and design efficient surveillance and control strategies, will depend on understanding this context dependent effect across habitats. More important, however, the research highlights the need for implementing multi-scenario modelling frameworks to reduce model uncertainty and to identify optimal trade-offs between model precision and complexity. Such development is in its infancy, and further research to correctly and consistently assess, and communicate uncertainty, surrounding spread modelling is needed. Informative assessments and clear communication of uncertainty will allow end-users and practitioners to make more informed decisions about the potential for invasive species establishment

Flexibility in object-based selection

A well established finding in the field of visual attention is that attention tends to operate in an object-based manner (i.e., all features of attended objects, including task-irrelevant ones, tend to be co-selected, e.g., O’Craven et al.). However, recent evidence suggests that object-based attention is not always obligatory; people can be pushed into prioritizing one object feature over another. The goal of the current study was to test the hypothesis that people can attend to multidimensional objects in a flexible manner even when there is no explicit benefit, and that this tendency varies across people. To test this idea, we ran four experiments using a priming of pop-out task in which participants searched for multidimensional targets (containing orientation and color). Orientation was always the target-defining and thus task-relevant feature, while color was always irrelevant to the task; importantly, this manipulation allowed us to measure the separate contributions of task-relevant and task-irrelevant features to selection (as measured by priming effects). We also predicted that people would vary in the extent to which they process the task-irrelevant feature, and that this variation could be predicted by individual differences in working memory capacity, executive functioning, or personality. Although we found significant priming color independent of orientation in all four experiments, we only observed significant orientation priming in Experiment 1. We also found a negative relationship between visual short-term memory (VSTM) capacity and consecutive priming effects for color in Experiment 1. Additionally, extraversion and neuroticism were significant predictors of overall color priming in Experiment 2. Taken together, our results indicate that limits in VSTM may increase susceptibility to recent visual trends, causing people to attribute importance to visual patterns that are systematic but meaningless. Additionally, we demonstrate that people can select objects in a flexible manner and use whichever feature is easiest to select to guide their attention, regardless of task-relevance

When Joints Fail: Identifying the Allergen Helps

More than 1 million joint replacement surgeries are performed each year in the United States, and failure occurs in 10% of them, raising major health and economic burdens. The reasons for failure are multiple and include malposition, infection, and hypersensitivity (HS)/allergy to implant components. The term "hypersensitivity", defining an inflammatory reaction to the implant components, is more appropriate than the term "allergy," because the implant-induced inflammation can be mediated by innate or adaptive immunity. Implant HS, also sometimes called "adverse reaction to metal debris" or "pseudotumor- like periprosthetic tissue reactions" in the specific condition or metal-on-metal hip replacement, undoubtedly exists, but it cannot be stated to always be an allergic reaction. Innate HS, also referred to as nonallergic HS, may develop in response to the generation of metal/polymer wear debris, which causes local inflammation due to activation of macrophages, thus leading to osteoclast triggering, bone resorption, and implant loosening. There is no diagnostic test for nonallergic HS. Conversely, adaptive HS, that is, allergy to prosthesis, also called type IV HS, is mediated by specific T cells that infiltrate the periimplant tissue where they are activated by antigen-presenting cells. The main allergens are metals (nickel, chromium, cobalt) and bone cement compounds. T-cell activation leads to the recruitment of leucocytes, which will cause joint inflammation, pain, and loosening

Flame Temperatures Saturate with Increasing Dead Material in <i>Ulex europaeus</i>, but Flame Duration, Fuel Consumption and Overall Flammability Continue to Increase

A key determinant of wildfire behaviour is the flammability of constituent plants. One plant trait that influences flammability is the retention of dead biomass, as the low moisture content of dead material means less energy is required to achieve combustion. However, the effect of the dead-to-live ratio of fuel on plant flammability has rarely been experimentally quantified. Here we examine the nature of the relationship between dead fuel accumulation and flammability in Ulex europaeus (common gorse). Shoots with varying proportions of dead material were ignited in a purpose-built plant-burner. Three components of flammability were measured: sustainability (flame duration), consumability (proportion burnt biomass) and combustibility (maximum temperature). While flame duration and proportion burnt biomass had a positive linear relationship with the proportion of dead material, the response of maximum temperature was positive but non-linear. All three flammability components were reduced to a single variable using principal components analysis; this had a non-linear relationship with the proportion of dead material. The response of maximum temperature to dead material plateaued at 39%. These findings have implications for the management of habitats invaded by gorse; to mitigate fire hazard associated with gorse, stands should be kept at a relatively young age when dead fuel is less prevalent

Time–frequency analysis to profile hydrological regimes: application to Haiti

Comprehensive characterization of its flow rates is prerequisite to a proper understanding and water management of a given hydrological region. Several studies question the soundness of stationarity in time series and suggest the need for a quantification of the events and non-stationary features in flow-rate time series. In this study, we combine statistical and time-frequency (TF) analyses to characterize and classify the flow rates of an understudied region, namely Haiti. Wavelet transforms and cyclostationarity analyses were combined with principal component analysis and hierarchical clustering to identify three groups of hydrological regimes in the country, suggesting similar managements: (i) relatively stable flow rates with TF behaviours; (ii) periodic and strongly seasonal flow rates; and (iii) unstable flow rates. We argue that the TF methodology can yield additional information in regard to flow events and multiscale behaviours, even for short records. Flow-rate characterization would predictably be more exhaustive if done with the approach described here

Model-free estimation of COVID-19 transmission dynamics from a complete outbreak.

New Zealand had 1499 cases of COVID-19 before eliminating transmission of the virus. Extensive contract tracing during the outbreak has resulted in a dataset of epidemiologically linked cases. This data contains useful information about the transmission dynamics of the virus, its dependence on factors such as age, and its response to different control measures. We use Monte-Carlo network construction techniques to provide an estimate of the number of secondary cases for every individual infected during the outbreak. We then apply standard statistical techniques to quantify differences between groups of individuals. Children under 10 years old are significantly under-represented in the case data. Children infected fewer people on average and had a lower probability of transmitting the disease in comparison to adults and the elderly. Imported cases infected fewer people on average and also had a lower probability of transmitting than domestically acquired cases. Superspreading is a significant contributor to the epidemic dynamics, with 20% of cases among adults responsible for 65-85% of transmission. Subclinical cases infected fewer individuals than clinical cases. After controlling for outliers serial intervals were approximated with a normal distribution (μ = 4.4 days, σ = 4.7 days). Border controls and strong social distancing measures, particularly when targeted at superspreading, play a significant role in reducing the spread of COVID-19