Species interactions in ephemeral patch systems: spatial, temporal, and spatio-temporal influences

This dissertation demonstrates the importance of spatial, temporal, and spatio-temporal mechanisms in influencing species interactions within ephemeral patch systems. This work extends prior theory using individual-based modeling to show that the autocorrelation of habitat can have a strong influence on plant-pollinator communities. Pollinators in plant-pollinator communities must regularly disperse to receptive plants, and in model systems often feed on ephemerally available seeds. Because the probability of a seed being eaten by a pollinator will be directly affected by the number of pollinators that visit a plant flower, the frequency at which seed-eating pollinators visit flowers has a major impact on the costs and benefits associated with the mutualism. High pollinator visitation increases per capita pollination, but also the number of seeds consumed. The number of pollinators visiting a plant is expected to increase with increasing plant density. Where plant habitat is especially dense, plant density will be high. If pollinator dispersal is limited, plants in these regions of high density will support high densities of pollinators that are able to move efficiently between plants. As a result of frequent pollinator visitation, plants with many nearby conspecific neighbors will produce disproportionately more pollinators than seeds. Because pollinators compete with non-pollinating exploiters of mutualisms, plants in these locations will also have lowered rates of exploitation. This is the case for the plant-pollinator interaction between the Sonoran Desert rock fig (Ficus petiolaris) and its wasp pollinator (Pegoscapus), wherein fig trees with a higher number of conspecific neighboring trees are visited by more foundress pollinators, produce fewer seeds, and are less likely to be exploited by non-pollinators. Because the costs, benefits, and stability of mutualisms with seed-eating pollinators are all strongly influenced by pollinator and exploiter birth rates, and because figs in particular are often a keystone resource for local frugivores, the work in this dissertation is of broad interest to ecology, evolution, and conservation. This dissertation also extends prior theory on competitors in ephemeral patch systems through the introduction of lottery models, which are used demonstrate how a temporal storage effect facilitates competitor coexistence when competitors develop within patches in overlapping generations. Conceptually unique to this work, the mechanism generating the temporal environmental variance on which coexistence relies is space itself, in the form of varying minimum between patch dispersal distance. When the minimum dispersal distance required to move from ephemeral patch to ephemeral patch changes over time, the superiority of competitors using patch resources can also change over time if they invest differently in fecundity versus dispersal ability. Given a trade-off in fecundity and dispersal ability, coexistence is predicted over a wide range of biologically realistic parameters for non-pollinating competitor fig wasps. An empirical prediction of this modeling work is that the fecundities of competitors in fig wasp communities will be negatively correlated with wasp dispersal abilities. Egg load estimates and two independent metrics of wasp dispersal ability show that non-pollinating competitors associated with F. petiolaris have negatively correlated fecundities and dispersal abilities. These results demonstrate that wasp population storage and a fecundity-dispersal ability trade-off are critical mechanisms for maintaining fig wasp diversity in at least one fig wasp community, and likely many others. And they more broadly demonstrate the importance of a fluctuating environment on species interactions and coexistence in ephemeral patch communities

Patient reported measures of informed consent for clinical trials : A systematic review

Funding: This work was supported by personal fellowship award (to KG - MR/L01193X/1) from the Medical Research Council’s Strategic Skills Methodology programme (https://www.mrc.ac.uk/). The Health Services Research Unit is supported by a core grant from the Chief Scientist Office of the Scottish Government Health and Social Care Directorates (http://www.cso.scot.nhs.uk/). This funding supported MKC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

abmAnimalMovement: An R package for simulating animal movement using an agent-based model

Animal movement datasets are growing in number and depth, and researchers require a growing number of analytical approaches to adequately answer questions using movement datasets. As the complexity of questions and analyses increase, deciding on the best approach both in terms of study design and analysis can become more difficult. A potential solution is to simulate an array of synthetic datasets under varying study designs and simulation parametrisations to gain insight into the impact of analysis choice(s) in different contexts. The abmAnimalMovement R package provides the means of simulating animal movement for this purpose. The abmAnimalMovement simulations use a discrete time agent-based model and does not require previous movement data as an input. The simulations include a number of key internal and external movement influences, as well as parameters for navigation and mobility capacity of the animal. Internal influences include three predefined behavioural states (e.g., rest, explore, forage) and any number of activity cycles (e.g., diel, seasonal). External influences are implemented via matrices describing landscape characteristics (e.g., shelter quality, foraging resources, movement ease), and predefined points describing shelter sites and points the animal aims to avoid. Navigation capacity is defined by the range the animal can dynamically choose a foraging location to which it is subsequently attracted. Mobility capacity is implemented by user defined distributions, from which step length and turn angles are draw at each time step, governing the possible subsequent locations of the animal. Critically, the navigation capacity (the choice of destination) operates on a different time scale to the mobility capacity, allowing the internal state of the animal to differ from the observed movements. When combined with other emergent properties, such as site fidelity generated via repeated shelter site use, the simulations offer opportunities to test whether movement analyses can accurately recover hidden mechanisms, states, and drivers. Keyword

A global systematic review of frugivorous animal tracking studies and the estimation of seed dispersal distances

Seed dispersal is one of the most important ecosystem functions globally. It shapes plant populations, enhances forest succession, and has multiple, indirect benefits for humans, yet it is one of the most threatened processes in plant regeneration, worldwide. Seed dispersal distances are determined by the diets, seed retention times and movements of frugivorous animals. Hence, understanding how we can most effectively describe frugivore movement and behaviour with rapidly developing animal tracking technology is key to quantifying seed dispersal. To assess the current use of animal tracking in frugivory studies and to provide a baseline for future studies, we provide a comprehensive review and synthesis on the existing primary literature of global tracking studies that monitor movement of frugivorous animals. Specifically, we identify studies that estimate dispersal distances and how they vary with body mass and environmental traits. We show that over the last two decades there has been a large increase in frugivore tracking studies that determine seed dispersal distances. However, some taxa (e.g. reptiles) and geographic locations (e.g. Africa and Central Asia) are poorly studied. Furthermore, we found that certain morphological and environmental traits can be used to predict seed dispersal distances. We demonstrate that flight ability and increased body mass both significantly increase estimated seed dispersal mean and maximum distances. Our results also suggest that protected areas have a positive effect on mean seed dispersal distances when compared to unprotected areas. We anticipate that this review will act as a reference for future frugivore tracking studies, specifically to target current taxonomic and geographic data gaps, and to further explore how seed dispersal relates to key frugivore and fruit traits

A global systematic review of frugivorous animal tracking studies and the estimation of seed dispersal distances

Seed dispersal is one of the most important ecosystem functions globally. It shapes plant populations, enhances forest succession, and has multiple, indirect benefits for humans, yet it is one of the most threatened processes in plant regeneration, worldwide. Seed dispersal distances are determined by the diets, seed retention times and movements of frugivorous animals. Hence, understanding how we can most effectively describe frugivore movement and behaviour with rapidly developing animal tracking technology is key to quantifying seed dispersal. To assess the current use of animal tracking in frugivory studies and to provide a baseline for future studies, we provide a comprehensive review and synthesis on the existing primary literature of global tracking studies that monitor movement of frugivorous animals. Specifically, we identify studies that estimate dispersal distances and how they vary with body mass and environmental traits. We show that over the last two decades there has been a large increase in frugivore tracking studies that determine seed dispersal distances. However, some taxa (e.g. reptiles) and geographic locations (e.g. Africa and Central Asia) are poorly studied. Furthermore, we found that certain morphological and environmental traits can be used to predict seed dispersal distances. We demonstrate that flight ability and increased body mass both significantly increase estimated seed dispersal mean and maximum distances. Our results also suggest that protected areas have a positive effect on mean seed dispersal distances when compared to unprotected areas. We anticipate that this review will act as a reference for future frugivore tracking studies, specifically to target current taxonomic and geographic data gaps, and to further explore how seed dispersal relates to key frugivore and fruit traits

The traits of "trait ecologists" : An analysis of the use of trait and functional trait terminology

Trait and functional trait approaches have revolutionized ecology improving our understanding of community assembly, species coexistence, and biodiversity loss. Focusing on traits promotes comparability across spatial and organizational scales, but terms must be used consistently. While several papers have offered definitions, it remains unclear how ecologists operationalize "trait" and "functional trait" terms. Here, we evaluate how researchers and the published literatures use these terms and explore differences among subdisciplines and study systems (taxa and biome). By conducting both a survey and a literature review, we test the hypothesis that ecologists' working definition of "trait" is adapted or altered when confronting the realities of collecting, analyzing and presenting data. From 486 survey responses and 712 reviewed papers, we identified inconsistencies in the understanding and use of terminology among researchers, but also limited inclusion of definitions within the published literature. Discrepancies were not explained by subdiscipline, system of study, or respondent characteristics, suggesting there could be an inconsistent understanding even among those working in related topics. Consistencies among survey responses included the use of morphological, phonological, and physiological traits. Previous studies have called for unification of terminology; yet, our study shows that proposed definitions are not consistently used or accepted. Sources of disagreement include trait heritability, defining and interpreting function, and dealing with organisms in which individuals are not clearly recognizable. We discuss and offer guidelines for overcoming these disagreements. The diversity of life on Earth means traits can represent different features that can be measured and reported in different ways, and thus, narrow definitions that work for one system will fail in others. We recommend ecologists embrace the breadth of biodiversity using a simplified definition of "trait" more consistent with its common use. Trait-based approaches will be most powerful if we accept that traits are at least as diverse as trait ecologists.Peer reviewe

Особенности распространения сигналов в высокоскоростных радиорелейных линиях связи

Статья посвящена современным высокоскоростным радиорелейным линиям связи. В частности, особенностям передачи и распространения сигналов в радиорелейной связи. Данный вид связи можно считать одним из самых стабильных с беспроводной передачей данных, где в качестве среды передачи используется свободное пространство (воздушное пространство), а также альтернативой волоконно-оптических линий связи (ВОЛС). В данный момент стоят задачи одновременного повышения пропускной способности, устойчивости к различным факторам среды передачи данных, а также дальности связи и рентабельности.The article is devoted to modern high-speed radio-relay communication lines. In particular, the features of the transmission and distribution of signal signals in radio relay communications. This type of communication can be considered one of the most stable types of communication with wireless data transmission, where free space (airspace) is used as a transmission medium, as well as an alternative to fiber-optic communication lines (FOCL). At the moment, the tasks are to simultaneously increase the throughput, resistance to various factors of the data transmission medium, as well as the communication range and profitability

Intrinsic calf factors associated with the behavior of healthy pre-weaned group-housed dairy-bred calves

Technology-derived behaviors are researched for disease detection in artificially-reared calves. Whilst existing studies demonstrate differences in behaviors between healthy and diseased calves, intrinsic calf factors (e.g., sex and birthweight) that may affect these behaviors have received little systematic study. This study aimed to understand the impact of a range of calf factors on milk feeding and activity variables of dairy-bred calves. Calves were group-housed from ~7 days to 39 days of age. Seven liters of milk replacer was available daily from an automatic milk feeder, which recorded feeding behaviors and live-weight. Calves were health scored daily and a tri-axial accelerometer used to record activity variables. Healthy calves were selected by excluding data collected 3 days either side of a poor health score or a treatment event. Thirty-one calves with 10 days each were analyzed. Mixed models were used to identify which of live-weight, age, sex, season of birth, age of inclusion into the group, dam parity, birthweight, and sire breed type (beef or dairy), had a significant influence on milk feeding and activity variables. Heavier calves visited the milk machine more frequently for shorter visits, drank faster and were more likely to drink their daily milk allowance than lighter calves. Older calves had a shorter mean standing bout length and were less active than younger calves. Calves born in summer had a longer daily lying time, performed more lying and standing bouts/day and had shorter mean standing bouts than those born in autumn or winter. Male calves had a longer mean lying bout length, drank more slowly and were less likely to consume their daily milk allowance than their female counterparts. Calves that were born heavier had fewer lying and standing bouts each day, a longer mean standing bout length and drank less milk per visit. Beef-sired calves had a longer mean lying bout length and drank more slowly than their dairy sired counterparts. Intrinsic calf factors influence different healthy calf behaviors in different ways. These factors must be considered in the design of research studies and the field application of behavior-based disease detection tools in artificially reared calves

TLR4 and NKT Cell Synergy in Immunotherapy against Visceral Leishmaniasis

NKT cells play an important role in autoimmune diseases, tumor surveillance, and infectious diseases, providing in most cases protection against infection. NKT cells are reactive to CD1d presented glycolipid antigens. They can modulate immune responses by promoting the secretion of type 1, type 2, or immune regulatory cytokines. Pathogen-derived signals to dendritic cells mediated via Toll like Receptors (TLR) can be modulated by activated invariant Natural Killer T (iNKT) cells. The terminal β-(1–4)-galactose residues of glycans can modulate host responsiveness in a T helper type-1 direction via IFN-γ and TLRs. We have attempted to develop a defined immunotherapeutic, based on the cooperative action of a TLR ligand and iNKT cell using a mouse model of visceral leishmaniasis. We evaluated the anti-Leishmania immune responses and the protective efficacy of the β-(1–4)-galactose terminal NKT cell ligand glycosphingophospholipid (GSPL) antigen of L. donovani parasites. Our results suggest that TLR4 can function as an upstream sensor for GSPL and provoke intracellular inflammatory signaling necessary for parasite killing. Treatment with GSPL was able to induce a strong effective T cell response that contributed to effective control of acute parasite burden and led to undetectable parasite persistence in the infected animals. These studies for the first time demonstrate the interactions between a TLR ligand and iNKT cell activation in visceral leishmaniasis immunotherapeutic