266 research outputs found

    The sedimentology of gravel beds in groundwater-dominated chalk streams: Implications for sediment modelling and management

    Get PDF
    Elevated fine sediment accumulation in a river system's gravel bed is known to cause detrimental ecological impacts. Current sediment targets and approaches to mitigation have failed due to the oversimplification of geomorphological processes controlling fine sediment accumulation and the lack of relevant scientific knowledge underpinning them. This is particularly apparent in chalk streams (groundwater-dominated systems) which regularly exhibit high rates of sediment accumulation despite low suspended sediment yields. A necessary first step is to better characterise their sedimentology; thus, the novelty of this study was to determine the sedimentological characteristics of chalk stream gravel beds, specifically the quantity and distribution of fine sediment with depth. We collated published and unpublished freeze-core data, encompassing 90 sites across 11 UK chalk streams. Results showed average quantities of fine sediment (75% of beds exceeding thresholds for ecological degradation. Quantities of fine sediment increased with increasing depth into the bed, with an average increase between surface and subsurface layers of 54%, and 89% of the gravel bed over-saturated with fine sediment. Regional differences were attributed to differences in stream power and local sediment sources, including surficial geology and catchment land use. Additionally, a major contrast was identified between experimental conditions in flume studies used to establish models describing interactions/mechanisms of fine sediment infiltration into immobile gravel beds and the natural conditions observed in chalk streams. As such, the use of such models as a basis to explore sediment management scenarios is unlikely to predict the outcome of such management techniques correctly in a real-world situation

    Critical research on populism: Nine rules of engagement

    Get PDF
    This article formulates precise questions and ‘rules of engagement’ designed to advance our understanding of the role populism can and should play in the present political conjuncture, with potentially significant implications for critical management and organization studies and beyond. Drawing on the work of Ernesto Laclau and others working within the post-Marxist discourse theory tradition, we defend a concept of populism understood as a form of reason that centres around a claim to represent ‘the people’, discursively constructed as an underdog in opposition to an illegitimate ‘elite’. A formal discursive approach to populism brings with it important advantages. For example, it establishes that a populist logic can be invoked to further very different political goals, from radical left to right, or from progressive to regressive. It sharpens too our grasp of important issues that are otherwise conflated and obfuscated. For instance, it helps us separate out the nativist and populist dimensions in the discourses of the United Kingdom Independence Party (UKIP), Trump or the Front National (FN). Our approach to populism, however, also points to the need to engage with the rhetoric about populism, a largely ignored area of critical research. In approaching populism as signifier, not only as a concept, we stress the added need to focus on the uses of the term ‘populism’ itself: how it is invoked, by whom, and to what purpose and effect. This, we argue, requires that we pay more systematic attention to anti-populism and ‘populist hype’, and reflect upon academia’s own relation to populism and anti-populism

    Effectiveness of a telephone-based intervention for smoking cessation in patients with severe mental disorders : Study protocol for a randomized controlled trial

    Get PDF
    Background: Up to 75% of inpatients with mental disorders smoke, and their life expectancy is decreased by up to 25 years compared to the general population. Hospitalized patients without monitoring after discharge quickly return to prehospitalization levels of tobacco use. The aim of the 061 QuitMental study is to assess the effectiveness of a multicomponent and motivational telephone-based intervention to stop smoking through a quitline addressed to smokers discharged from mental health hospital wards. Methods: A pragmatic randomized controlled trial, single blinded, will include 2:1 allocation to the intervention group (IG) and the control group (CG). The IG will receive telephone assistance to quit smoking (including psychological and psychoeducational support, and pharmacological treatment advice if required) proactively for 12 months, and the CG will receive only brief advice after discharge. The sample size, calculated with an expected difference of 15 points on smoking abstinence between groups (IG, 20% and CG, 5%), α = 0.05, ÎČ = 0.10, and 20% loss, will be 334 participants (IG) and 176 participants (CG). Participants are adult smokers discharged from psychiatric units of five acute hospitals. Measurements include dependent variables (self-reported 7-day point prevalence smoking abstinence (carbon monoxide verified), duration of abstinence, number of quit attempts, motivation, and self-efficacy to quit) and independent variables (age, sex, and psychiatric diagnoses). In data analysis, IG and CG data will be compared at 48 h and 1, 6, and 12 months post discharge. Multivariate logistic regression (odds ratio; 95% confidence interval) of dependent variables adjusted for potential confounding variables will be performed. The number needed to treat to achieve one abstinence outcome will be calculated. We will compare the abstinence rate of enrolled patients between groups. Discussion: This trial evaluates an innovative format of a quitline for smokers with severe mental disorders regardless of their motivation to quit. If effective, the pragmatic nature of the study will permit transfer to routine clinical practice in the National Health System. Trial registration: ClinicalTrials.gov, NCT03230955. Registered on 24 July 2017

    Effectiveness of a telephone-based intervention for smoking cessation in patients with severe mental disorders: study protocol for a randomized controlled trial

    Get PDF
    Background: up to 75% of inpatients with mental disorders smoke, and their life expectancy is decreased by up to 25 years compared to the general population. Hospitalized patients without monitoring after discharge quickly return to prehospitalization levels of tobacco use. The aim of the 061 QuitMental study is to assess the effectiveness of a multicomponent and motivational telephone-based intervention to stop smoking through a quitline addressed to smokers discharged from mental health hospital wards. Methods: a pragmatic randomized controlled trial, single blinded, will include 2:1 allocation to the intervention group (IG) and the control group (CG). The IG will receive telephone assistance to quit smoking (including psychological and psychoeducational support, and pharmacological treatment advice if required) proactively for 12 months, and the CG will receive only brief advice after discharge. The sample size, calculated with an expected difference of 15 points on smoking abstinence between groups (IG, 20% and CG, 5%), α = 0.05, ÎČ = 0.10, and 20% loss, will be 334 participants (IG) and 176 participants (CG). Participants are adult smokers discharged from psychiatric units of five acute hospitals. Measurements include dependent variables (self-reported 7-day point prevalence smoking abstinence (carbon monoxide verified), duration of abstinence, number of quit attempts, motivation, and self-efficacy to quit) and independent variables (age, sex, and psychiatric diagnoses). In data analysis, IG and CG data will be compared at 48 h and 1, 6, and 12 months post discharge. Multivariate logistic regression (odds ratio; 95% confidence interval) of dependent variables adjusted for potential confounding variables will be performed. The number needed to treat to achieve one abstinence outcome will be calculated. We will compare the abstinence rate of enrolled patients between groups. Discussion: this trial evaluates an innovative format of a quitline for smokers with severe mental disorders regardless of their motivation to quit. If effective, the pragmatic nature of the study will permit transfer to routine clinical practice in the National Health System

    Online Hate: From the Far-Right to the ‘Alt-Right’, and from the Margins to the Mainstream

    Get PDF
    In the 1990s and early 2000s, there was much discussion about the democratic and anti-democratic implications of the Internet. The latter particularly focused on the ways in which the far-right were using the Internet to spread hate and recruit members. Despite this common assumption, the American far-right did not harness the Internet quickly, effectively or widely. More recently, however, they have experienced a resurgence and mainstreaming, benefitting greatly from social media. This chapter examines the history of their use of the Internet with respect to: (1) how this developed in response to political changes and emerging technologies; (2) how it reflected and changed the status of such movements and their brand of hate; and (3) the relationship between online activity and traditional methods of communication

    Chronic Dietary Exposure to a Low-Dose Mixture of Genistein and Vinclozolin Modifies the Reproductive Axis, Testis Transcriptome, and Fertility

    Get PDF
    Background: The reproductive consequences and mechanisms of action of chronic exposure to low-dose endocrine disruptors are poorly understood.[br/] Objective: We assessed the effects of a continuous, low-dose exposure to a phytoestrogen (genistein) and/or an antiandrogenic food contaminant (vinclozolin) on the male reproductive tract and fertility.[br/] Methods: Male rats were exposed by gavage to genistein and vinclozolin from conception to adulthood, alone or in combination, at low doses (1 mg/kg/day) or higher doses (10 and 30 mg/kg/day). We studied a number of standard reproductive toxicology end points and also assessed testicular mRNA expression profiles using long-oligonucleotide microarrays.[br/] Results: The low-dose mixture and high-dose vinclozolin produced the most significant alterations in adults: decreased sperm counts, reduced sperm motion parameters, decreased litter sizes, and increased post implantation loss. Testicular mRNA expression profiles for these exposure conditions were strongly correlated. Functional clustering indicated that many of the genes induced belong to the “neuroactive ligand-receptor interactions” family encompassing several hormonally related actors (e.g., follicle-stimulating hormone and its receptor). All exposure conditions decreased the levels of mRNAs involved in ribosome function, indicating probable decreased protein production.[br/] Conclusions: Our study shows that chronic exposure to a mixture of a dose of a phytoestrogen equivalent to that in the human diet and a low dose—albeit not environmental—of a common anti-androgenic food contaminant may seriously affect the male reproductive tract and fertility

    Selective Trihydroxyazepane NagZ Inhibitors Increase Sensitivity of Pseudomonas Aeruginosa to ÎČ-lactams

    Get PDF
    AmpC ÎČ-lactamase confers resistance to ÎČ-lactam antibiotics in many Gram negative bacteria. Inducible expression of AmpC requires an N-acetylglucosaminidase termed NagZ. Here we describe the synthesis and characterization of hydroxyazepane inhibitors of NagZ. We find that these inhibitors enhance the susceptibility of clinically relevant Pseudomonas aeruginosa to ÎČ-lactams

    Construction and Analysis of High-Complexity Ribosome Display Random Peptide Libraries

    Get PDF
    Random peptide libraries displayed on the ribosome are becoming a new tool for the in vitro selection of biologically relevant macromolecules, including epitopes, antagonists, enzymes, and cell-surface receptors. Ribosome display is a cell-free system of coupling individual nascent proteins (phenotypes) to their corresponding mRNA (genotypes) by the formation of stable protein-ribosome-mRNA complexes and permitting the selection of a functional nascent protein by iterative cycles of panning and reverse transcription-polymerase chain reaction (RT-PCR) amplification in vitro. The complexity of the random peptide library is critical for the success of a panning experiment; greater the diversity of sequences within the library, the more likely it is that the library comprises sequences that can bind a given target with specific affinity. Here, we have used the cell-free system Escherichia coli S30 lysate to construct high-complexity random peptide libraries (>1014 independent members) by introducing strategies that are different from the methods described by Mattheakis et al. and Lamla et al. The key step in our method is to produce nanomole (nmol) amounts of DNA elements that are necessary for in vitro transcription/translation by using PCR but not plasmid DNA. Library design strategies and protocols that facilitate rapid identification are also presented

    Semi-automated Magnetic Bead-Based Antibody Selection from Phage Display Libraries

    Get PDF
    Phage display of combinatorial antibody libraries is a very efficient method for selecting recombinant antibodies against a wide range of molecules. It has been applied very successfully for the generation of therapeutic antibodies for more than a decade. To increase robustness and reproducibility of the selection procedure, we developed a semi-automated selection method for the generation of recombinant antibodies from phage display libraries. In this procedure, the selection targets are specifically immobilised to magnetic particles which can then by automatically handled by a magnetic particle processor. At present up to 96 samples can be handled simultaneously. Applying the processor allows standardisation of panning parameters such as washing conditions, incubation times, or to perform parallel selections on same targets under different buffer conditions. Additionally, the whole protocol has been streamlined to carry out bead loading, phage selection, phage amplification between selection rounds and magnetic particle ELISA for confirmation of binding activity in microtiter plate formats. Until now, this method has been successfully applied to select antibody fragments against different types of target, such as peptides, recombinant or homologous proteins, or chemical compounds
    • 

    corecore