Using willow riparian buffer strips for biomass production and riparian protection

Non-Peer ReviewedThere is increasing interest in the development of willow biomass as a renewable source of energy and woody lignocellulosic feedstock for bioproducts. Riparian buffers have been identified as an effective barrier to soil and nutrient movement from agricultural fields into watercourse. Willows are ideal riparian species in that they are well adapted to growing conditions in riparian zones and they vigorously re-grow following coppicing which allows them to be harvested for biomass in 3-4 year cycles. Characteristically riparian edges are highly productive due to water availability, therefore it is anticipated that willow biomass yield per unit area in riparian zones would be attractive. Research is being conducted to determine if using riparian buffer strips for willow biomass production provides energy alternatives and economic opportunities for land owners, but also leads to environmental benefits such as reduced erosion and nutrient leaching and preservation of water quality

Debunking the myth of the endogenous antiangiogenic Vegfaxxxb transcripts

In this opinion article we critically assess evidence for the existence of a family of antiangiogenic vascular endothelial growth factor (Vegfaxxxb) transcripts, arising from the use of a phylogenetically conserved alternative distal splice site within exon 8 of the VEGFA gene. We explain that prior evidence for Vegfaxxxb transcripts in tissues rests heavily upon flawed RT-PCR methodologies, with the extensive use of 5′-tailing in primer design being the main issue. Furthermore, our analysis of large RNA-seq data sets (human and ovine) fails to identify a single Vegfaxxxb transcript. Therefore, we challenge the very existence of Vegfaxxxb transcripts, which further questions the physiological relevance of studies based on the use of ‘anti-VEGFAxxxb’ antibodies. Our analysis has implications for the proposed therapeutic use of isoform-specific anti-VEGFA strategies for treating cancer and retinopathies

In situ vertical observations of the layered structure of air pollution in a continental high-latitude urban boundary layer during winter

Vertical in situ measurements of aerosols and trace gases were conducted in Fairbanks, Alaska, during winter 2022 as part of the Alaskan Layered Pollution and Chemical Analysis campaign (ALPACA). Using a tethered balloon, the study explores the dispersion of pollutants in the continental high-latitude stable boundary layer (SBL). Analysis of 24 flights revealed a stratified SBL structure with different pollution layers in the lowest tens of meters of the atmosphere, offering unprecedented detail. Surface emissions generally accumulated in a surface mixing layer (ML) extending to an average of 51 m, with a well-mixed sublayer (MsL) reaching 22 m. The height and concentrations within the ML were strongly influenced by a local wind driven by nearby topography under anticyclonic conditions. During strong radiative cooling, a drainage flow increased turbulence near the surface, altering the temperature profile and deepening the ML. Above the ML, pollution concentrations decreased but showed clear signs of freshly released anthropogenic emissions. Higher in the atmosphere, above elevated inversions, pollution levels were similar to previously reported Arctic haze concentrations, even though Fairbanks' outflow concentrations below elevated inversions were up to 6 times higher, likely due to power plant emissions. In situ measurements indicated that gas and particle tracer ratios in elevated power plant plumes differed significantly from those near the surface. Overall, pollution layers were strongly correlated with the temperature stratification and emission heights, emphasizing the need for improved representation of temperature inversions and emission sources in air quality models to enhance pollution forecasts

Surface distributions and vertical profiles of trace gases (CO, O3, NO, NO2) in the Arctic wintertime boundary layer using low-cost sensors during ALPACA-2022

Electrochemical gas sensors (EGSs) have been used to measure the surface distributions and vertical profiles of trace gases in the wintertime Arctic boundary layer during the Alaskan Layered Pollution and Chemical Analysis (ALPACA) field experiment in Fairbanks, Alaska, in January–February 2022. The MICRO sensors for MEasurements of GASes (MICROMEGAS) instrument set up with CO, NO, NO2, and O3 EGSs was operated on the ground at an outdoor reference site in downtown Fairbanks for calibration, while on board a vehicle moving through the city and its surroundings and on board a tethered balloon, the helikite, at a site at the edge of the city. To calibrate the measurements, a set of machine learning (ML) calibration methods were tested. For each method, learning and prediction were performed with coincident MICROMEGAS and reference analyser measurements at the downtown site. For CO, the calibration parameters provided by the manufacturer led to the best agreement between the EGS and the reference analyser, and no ML method was needed for calibration. The Pearson correlation coefficient R is 0.82, and the slope of the linear regression between MICROMEGAS and reference data is 1.12. The mean bias is not significant, but the root mean square error (290 ppbv, parts per billion by volume) is rather large because of CO concentrations reaching several ppmv (parts per million by volume) in downtown Fairbanks. For NO, NO2, and O3, the best agreements for the prediction datasets were obtained with an artificial neural network, the multi-layer perceptron. For these three gases, the correlation coefficients are higher than 0.95, and the slopes of linear regressions with the reference data are in the range 0.93–1.04. The mean biases, which are 1 ± 3, 0 ± 4, and 3 ± 12 ppbv for NO2, O3, and NO, respectively, are not significant. Measurements from the car round of 21 January are presented to highlight the ability of MICROMEGAS to quantify the surface variability in the target trace gases in Fairbanks and the surrounding hills. MICROMEGAS flew 11 times from the ground up to a maximum of 350 m above ground level (a.g.l.) on board the helikite at the site at the edge of the city. The statistics performed over the helikite MICROMEGAS dataset show that the median vertical gas profiles are characterized by almost constant mixing ratios. The median values over the vertical are 140, 8, 4, and 32 ppbv for CO, NO, NO2, and O3. Extreme values are detected with low-O3 and high-NO2 and NO concentrations between 100 and 150 m a.g.l. O3 minimum levels (5th percentile) of 5 ppbv are coincident with NO2 maximum levels (95th percentile) of 40 ppbv, which occur around 200 m a.g.l. The peaks aloft are linked to pollution plumes originating from Fairbanks power plants such as those documented during the flight on 20 February

Questions of presence

This article considers some of the ways in which ‘the black woman’ as both representation and embodied, sentient being is rendered visible and invisible and to link these to the multiple and competing ways in which she is ‘present’. The issues are engaged through three distinct but overlapping conceptualisations of ‘presence’. ‘Presence’ as conceived (and highly contested) in performance studies; ‘presence’ as conceived and worked with in psychoanalysis; and ‘presence’ as decolonising political praxis among indigenous communities. I use these conceptualisations of presence to consider the various ways in which the black woman as figure and as embodied/sentient subject has been made present/absent in different discursive registers. I also explore what is foreclosed and how this is itself linked to legacies of colonial ‘worlding’. I end with consideration of alternative modes of black women’s presence and how this offers a resource for new modes of sociality. Keywords Black women; presence; colonial violence; de-gendering; psychosocial; triangular spac