130 research outputs found

    Marine anthropogenic litter on British beaches: a 10-year nationwide assessment using citizen science data

    Get PDF
    Growing evidence suggests that anthropogenic litter, particularly plastic, represents a highly pervasive and persistent threat to global marine ecosystems. Multinational research is progressing to characterise its sources, distribution and abundance so that interventions aimed at reducing future inputs and clearing extant litter can be developed. Citizen science projects, whereby members of the public gather information, offer a low-cost method of collecting large volumes of data with considerable temporal and spatial coverage. Furthermore, such projects raise awareness of environmental issues and can lead to positive changes in behaviours and attitudes. We present data collected over a decade (2005-2014 inclusive) by Marine Conservation Society (MCS) volunteers during beach litter surveys carried along the British coastline, with the aim of increasing knowledge on the composition, spatial distribution and temporal trends of coastal debris. Unlike many citizen science projects, the MCS beach litter survey programme gathers information on the number of volunteers, duration of surveys and distances covered. This comprehensive information provides an opportunity to standardise data for variation in sampling effort among surveys, enhancing the value of outputs and robustness of findings. We found that plastic is the main constituent of anthropogenic litter on British beaches and the majority of traceable items originate from land-based sources, such as public littering. We identify the coast of the Western English Channel and Celtic Sea as experiencing the highest relative litter levels. Increasing trends over the 10-year time period were detected for a number of individual item categories, yet no statistically significant change in total (effort-corrected) litter was detected. We discuss the limitations of the dataset and make recommendations for future work. The study demonstrates the value of citizen science data in providing insights that would otherwise not be possible due to logistical and financial constraints of running government-funded sampling programmes on such large scales

    Branching dendrites with resonant membrane: a “sum-over-trips” approach

    Get PDF
    Dendrites form the major components of neurons. They are complex branching structures that receive and process thousands of synaptic inputs from other neurons. It is well known that dendritic morphology plays an important role in the function of dendrites. Another important contribution to the response characteristics of a single neuron comes from the intrinsic resonant properties of dendritic membrane. In this paper we combine the effects of dendritic branching and resonant membrane dynamics by generalising the “sum-over-trips” approach (Abbott et al. in Biol Cybernetics 66, 49–60 1991). To illustrate how this formalism can shed light on the role of architecture and resonances in determining neuronal output we consider dual recording and reconstruction data from a rat CA1 hippocampal pyramidal cell. Specifically we explore the way in which an Ih current contributes to a voltage overshoot at the soma

    An Open-Format Enteroid Culture System for Interrogation of Interactions Between Toxoplasma gondii and the Intestinal Epithelium

    Get PDF
    When transmitted through the oral route, Toxoplasma gondii first interacts with its host at the small intestinal epithelium. This interaction is crucial to controlling initial invasion and replication, as well as shaping the quality of the systemic immune response. It is therefore an attractive target for the design of novel vaccines and adjuvants. However, due to a lack of tractable infection models, we understand surprisingly little about the molecular pathways that govern this interaction. The in vitro culture of small intestinal epithelium as 3D enteroids shows great promise for modeling the epithelial response to infection. However, the enclosed luminal space makes the application of infectious agents to the apical epithelial surface challenging. Here, we have developed three novel enteroid-based techniques for modeling T. gondii infection. In particular, we have adapted enteroid culture protocols to generate collagen-supported epithelial sheets with an exposed apical surface. These cultures retain epithelial polarization, and the presence of fully differentiated epithelial cell populations. They are susceptible to infection with, and support replication of, T. gondii. Using quantitative label-free mass spectrometry, we show that T. gondii infection of the enteroid epithelium is associated with up-regulation of proteins associated with cholesterol metabolism, extracellular exosomes, intermicrovillar adhesion, and cell junctions. Inhibition of host cholesterol and isoprenoid biosynthesis with Atorvastatin resulted in a reduction in parasite load only at higher doses, indicating that de novo synthesis may support, but is not required for, parasite replication. These novel models therefore offer tractable tools for investigating how interactions between T. gondii and the host intestinal epithelium influence the course of infection

    Aromatase inhibitors as adjuvant therapy for postmenopausal women: a therapeutic advance but many unresolved questions

    Get PDF
    Adjuvant hormonal therapy for postmenopausal women with early stage breast cancer has become far more complex over the past several years. This commentary reviews the current status of the five major trials evaluating the use of the aromatase inhibitors in the adjuvant setting. The data currently available suggest that the aromatase inhibitors are efficacious either as upfront therapy or after a course of tamoxifen. Ongoing trials will compare these approaches and guide the use of these agents in the years to come

    Developing a 3D intestinal epithelium model for livestock species

    Get PDF
    © 2018, The Author(s). The in vitro 3D culture of intestinal epithelium is a valuable resource in the study of its function. Organoid culture exploits stem cells’ ability to regenerate and produce differentiated epithelium. Intestinal organoid models from rodent or human tissue are widely available whereas large animal models are not. Livestock enteric and zoonotic diseases elicit significant morbidity and mortality in animal and human populations. Therefore, livestock species-specific models may offer novel insights into host-pathogen interactions and disease responses. Bovine and porcine jejunum were obtained from an abattoir and their intestinal crypts isolated, suspended in Matrigel, cultured, cryopreserved and resuscitated. ‘Rounding’ of crypts occurred followed by budding and then enlargement of the organoids. Epithelial cells were characterised using immunofluorescent staining and confocal microscopy. Organoids were successfully infected with Toxoplasma gondii or Salmonella typhimurium. This 3D organoid model offers a long-term, renewable resource for investigating species-specific intestinal infections with a variety of pathogens

    Does home neighbourhood supportiveness influence the location more than volume of adolescent's physical activity? An observational study using Global Positioning Systems

    Get PDF
    Background: Environmental characteristics of home neighbourhoods are hypothesised to be associated with residents’ physical activity levels, yet many studies report only weak or equivocal associations. We theorise that this may be because neighbourhood characteristics influence the location of activity more than the volume. Using a sample of UK adolescents, we examine the role of home neighbourhood supportiveness for physical activity, both in terms of volume of activity undertaken and a measure of proximity to home at which activity takes place. Methods: Data were analysed from 967 adolescents living in and around the city of Bristol, UK. Each participant wore an accelerometer and a GPS device for seven days during school term time. These data were integrated into a Geographical Information System containing information on the participants’ home neighbourhoods and measures of environmental supportiveness. We then identified the amount of out-of-school activity of different intensities that adolescents undertook inside their home neighbourhood and examined how this related to home neighbourhood supportiveness. Results: We found that living in a less supportive neighbourhood did not negatively impact the volume of physical activity that adolescents undertook. Indeed these participants recorded similar amounts of activity (e.g. 20.5 mins per day of moderate activity at weekends) as those in more supportive neighbourhoods (18.6 mins per day). However, the amount of activity adolescents undertook inside their home neighbourhood did differ according to supportiveness; those living in less supportive locations had lower odds of recording activity inside their home neighbourhood. This was observed across all intensities of activity including sedentary, light, moderate, and vigorous. Conclusions: Our findings suggest that the supportiveness of the neighbourhood around home may have a greater influence on the location of physical activity than the volume undertaken. This finding is at odds with the premise of the socio-ecological models of physical activity that have driven this research field for the last two decades, and has implications for future research, as by simply measuring volumes of activity we may be underestimating the impact of the environment on physical activity behaviours

    Improved precision on the experimental E0 decay branching ratio of the Hoyle state

    Get PDF
    Stellar carbon synthesis occurs exclusively via the 3α3\alpha process, in which three α\alpha particles fuse to form 12^{12}C in the excited Hoyle state, followed by electromagnetic decay to the ground state. The Hoyle state is above the α\alpha threshold, and the rate of stellar carbon production depends on the radiative width of this state. The radiative width cannot be measured directly, and must instead be deduced by combining three separately measured quantities. One of these quantities is the E0E0 decay branching ratio of the Hoyle state, and the current 1010\% uncertainty on the radiative width stems mainly from the uncertainty on this ratio. The E0E0 branching ratio was deduced from a series of pair conversion measurements of the E0E0 and E2E2 transitions depopulating the 02+0^+_2 Hoyle state and 21+2^+_1 state in 12^{12}C, respectively. The excited states were populated by the 12^{12}C(p,pâ€Č)(p,p^\prime) reaction at 10.5 MeV beam energy, and the pairs were detected with the electron-positron pair spectrometer, Super-e, at the Australian National University. The deduced branching ratio required knowledge of the proton population of the two states, as well as the alignment of the 21+2^+_1 state in the reaction. For this purpose, proton scattering and Îł\gamma-ray angular distribution experiments were also performed. An E0E0 branching ratio of ΓπE0/Γ=8.2(5)×10−6\Gamma^{E0}_{\pi}/\Gamma=8.2(5)\times10^{-6} was deduced in the current work, and an adopted value of ΓπE0/Γ=7.6(4)×10−6\Gamma^{E0}_{\pi}/\Gamma=7.6(4)\times10^{-6} is recommended based on a weighted average of previous literature values and the new result. The new recommended value for the E0E0 branching ratio is about 14% larger than the previous adopted value of ΓπE0/Γ=6.7(6)×10−6\Gamma^{E0}_{\pi}/\Gamma=6.7(6)\times10^{-6}, while the uncertainty has been reduced from 9% to 5%.Comment: Accepted for publication as a Regular Article in Phys. Rev. C on July 29 202

    A neural integrator model for planning and value-based decision making of a robotics assistant

    Get PDF
    Modern manufacturing and assembly environments are characterized by a high variability in the built process which challenges human–robot cooperation. To reduce the cognitive workload of the operator, the robot should not only be able to learn from experience but also to plan and decide autonomously. Here, we present an approach based on Dynamic Neural Fields that apply brain-like computations to endow a robot with these cognitive functions. A neural integrator is used to model the gradual accumulation of sensory and other evidence as time-varying persistent activity of neural populations. The decision to act is modeled by a competitive dynamics between neural populations linked to different motor behaviors. They receive the persistent activation pattern of the integrators as input. In the first experiment, a robot learns rapidly by observation the sequential order of object transfers between an assistant and an operator to subsequently substitute the assistant in the joint task. The results show that the robot is able to proactively plan the series of handovers in the correct order. In the second experiment, a mobile robot searches at two different workbenches for a specific object to deliver it to an operator. The object may appear at the two locations in a certain time period with independent probabilities unknown to the robot. The trial-by-trial decision under uncertainty is biased by the accumulated evidence of past successes and choices. The choice behavior over a longer period reveals that the robot achieves a high search efficiency in stationary as well as dynamic environments.The work received financial support from FCT through the PhD fellowships PD/BD/128183/2016 and SFRH/BD/124912/2016, the project “Neurofield” (PTDC/MAT-APL/31393/2017) and the research centre CMAT within the project UID/MAT/00013/2013

    Lung tumour markers in oncology practice: a study of TPA and CA125

    Get PDF
    Several substances mark the course of lung cancer and may reliably help the clinician in decision-making. This is the first clinical study specifically designed to compare tissue polypeptide antigen and CA 125 tumour associated antigen. Three hundred and eighty-four new lung cancer patients (309 males) were studied at their first clinical presentation and then strictly followed-up. Anthropometric, clinical and laboratory data – including tissue polypeptide antigen and CA 125 tumour associated antigen serum levels – were prospectively recorded. A total of 1000 tissue polypeptide antigen and CA 125 tumour associated antigen serum assays (384 pre-treatment and 616 posttreatment assays) were performed. Both tissue polypeptide antigen and CA 125 tumour associated antigen correlated significantly with the T, N and M stage descriptors at diagnosis (Rho: 0.200, 0.203, 0.263 and 0.181, 0.240, 0.276, respectively), and then with the objective response to treatment (Rho: 0.388 and 0.207, respectively). A pleural neoplastic involvement was mainly associated to an increase of CA 125 tumour associated antigen (Rho: 0.397). Both tissue polypeptide antigen and CA 125 tumour associated antigen were strongly predictive of the patients' outcome, as assessed by the univariate analysis of survival (log-rank test: 37.24 and 29.01) and several Cox' proportional hazards regression models. The two marker tests are similarly helpful and appear complementary, given the low inter-marker correlation and their independent prognostic capability

    A Thalamocortical Neural Mass Model of the EEG during NREM Sleep and Its Response to Auditory Stimulation

    Get PDF
    Few models exist that accurately reproduce the complex rhythms of the thalamocortical system that are apparent in measured scalp EEG and at the same time, are suitable for large-scale simulations of brain activity. Here, we present a neural mass model of the thalamocortical system during natural non-REM sleep, which is able to generate fast sleep spindles (12–15 Hz), slow oscillations (<1 Hz) and K-complexes, as well as their distinct temporal relations, and response to auditory stimuli. We show that with the inclusion of detailed calcium currents, the thalamic neural mass model is able to generate different firing modes, and validate the model with EEG-data from a recent sleep study in humans, where closed-loop auditory stimulation was applied. The model output relates directly to the EEG, which makes it a useful basis to develop new stimulation protocols
    • 

    corecore