Technical Note: The use of an interrupted-flow centrifugation method to characterise preferential flow in low permeability media

We present an interrupted-flow centrifugation technique to characterise preferential flow in low permeability media. The method entails a minimum of three phases: centrifuge-induced flow, no flow and centrifuge-induced flow, which may be repeated several times in order to most effectively characterise multi-rate mass transfer behaviour. In addition, the method enables accurate simulation of relevant in situ total stress conditions during flow by selecting an appropriate centrifugal force. We demonstrate the utility of the technique for characterising the hydraulic properties of smectite-clay-dominated core samples. All core samples exhibited a non-Fickian tracer breakthrough (early tracer arrival), combined with a decrease in tracer concentration immediately after each period of interrupted flow. This is indicative of dual (or multi-)porosity behaviour, with solute migration predominately via advection during induced flow, and via molecular diffusion (between the preferential flow network(s) and the low hydraulic conductivity domain) during interrupted flow. Tracer breakthrough curves were simulated using a bespoke dual porosity model with excellent agreement between the data and model output (Nash–Sutcliffe model efficiency coefficient was > 0.97 for all samples). In combination, interrupted-flow centrifuge experiments and dual porosity transport modelling are shown to be a powerful method to characterise preferential flow in low permeability media

Management of South Texas Mixed Brush With Herbicides.

72 p

Introduction to special section on the U.S. IOOS coastal and ocean modeling testbed

Strong and strategic collaborations among experts from academia, federal operational centers, and industry have been forged to create a U.S. IOOS Coastal and Ocean Modeling Testbed (COMT). The COMT mission is to accelerate the transition of scientific and technical advances from the coastal and ocean modeling research community to improved operational ocean products and services. This is achieved via the evaluation of existing technology or the development of new technology depending on the status of technology within the research community. The initial phase of the COMT has addressed three coastal and ocean prediction challenges of great societal importance: estuarine hypoxia, shelf hypoxia, and coastal inundation. A fourth effort concentrated on providing and refining the cyberinfrastructure and cyber tools to support the modeling work and to advance interoperability and community access to the COMT archive. This paper presents an overview of the initiation of the COMT, the findings of each team and a discussion of the role of the COMT in research to operations and its interface with the coastal and ocean modeling community in general. Detailed technical results are presented in the accompanying series of 16 technical papers in this special issue

Factors Associated with HIV Disclosure Status among iENGAGE Cohort of New to HIV Care Patients

HIV disclosure is an important behavior with implications for HIV treatment and prevention but understudied among new to HIV care patients who face unique challenges adjusting to a new diagnosis. This study evaluated the factors associated with HIV disclosure status and patterns of HIV disclosure among new to HIV care patients. A cross-sectional study was conducted evaluating the iENGAGE (integrating ENGagement and Adherence Goals upon Entry) cohort. Participants were enrolled in this randomized behavioral trial between December 2013 and June 2016. The primary and secondary outcomes included HIV disclosure status (Yes/No) and patterns of disclosure (Broad, Selective and Nondisclosure), respectively. Logistic and Multinomial Logistic Regression were used to evaluate the association of participant factors with HIV disclosure and patterns of HIV disclosure, respectively. Of 371 participants, the average age was 37 ± 12 years, 79.3% were males, and 62.3% were African Americans. A majority of participants (78.4%) disclosed their HIV status at baseline, 63.1% were broad disclosers and 15.2% were selective disclosers. In multivariable regression, black race, emotional support, and unmet needs predicted any HIV and broad disclosure, whereas males, emotional support, active coping, and acceptance were associated with selective disclosure. Interventions to promote early disclosure should focus on coping strategies and unmet needs, particularly among black and male people living with HIV initiating care

Physicochemical composition of wastes and co-located environmental designations at legacy mine sites in the south west of England and Wales: Implications for their resource potential

© 2016 This work examines the potential for resource recovery and/or remediation of metalliferous mine wastes in the south west of England and Wales. It does this through an assessment of the physicochemical composition of several key metalliferous legacy mine waste piles and an analysis of their co-location with cultural, geological and ecological designations. Mine waste samples were taken from 14 different sites and analysed for metal content, mineralogy, paste pH, particle size distribution, total organic carbon and total inorganic carbon. The majority of sites contain relatively high concentrations (in some cases up to several % by mass) of metals and metalloids, including Cu, Zn, As, Pb, Ag and Sn, many of which exceed ecological and/or human health risk guideline concentrations. However, the economic value of metals in the waste could be used to offset rehabilitation costs. Spatial analysis of all metalliferous mine sites in the south west of England and Wales found that around 70% are co-located with at least one cultural, geological and ecological designation. All 14 sites investigated are co-located with designations related to their mining activities, either due to their historical significance, rare species assemblages or geological characteristics. This demonstrates the need to consider the cultural and environmental impacts of rehabilitation and/or resource recovery on such sites. Further work is required to identify appropriate non-invasive methodologies to allow sites to be rehabilitated at minimal cost and disturbance

Recent abacavir use increases risk of type 1 and type 2 myocardial infarctions among adults with HIV

Background: There is persistent confusion as to whether abacavir (ABC) increases the risk of myocardial infarction (MI), and whether such risk differs by type 1 (T1MI) or 2 (T2MI) MI in adults with HIV. Methods: Incident MIs in North American Cohort Collaboration on Research and Design participants were identified from 2001 to 2013. Discrete time marginal structural models addressed channeling biases and time-dependent confounding to estimate crude hazard ratio (HR) and adjusted hazard ratio (aHR) and 95% confidence intervals; analyses were performed for T1MI and T2MI separately. A sensitivity analysis evaluated whether Framingham risk score (FRS) modified the effect of ABC on MI occurrence. Results: Eight thousand two hundred sixty-five adults who initiated antiretroviral therapy contributed 29,077 person-years and 123 MI events (65 T1MI and 58 T2MI). Median follow-up time was 2.9 (interquartile range 1.4-5.1) years. ABC initiators were more likely to have a history of injection drug use, hepatitis C virus infection, hypertension, diabetes, impaired kidney function, hyperlipidemia, low (,200 cells/mm3) CD4 counts, and a history of AIDS. The risk of the combined MI outcome was greater for persons who used ABC in the previous 6 months [aHR = 1.84 (1.17-2.91)]; and persisted for T1MI (aHR = 1.62 [1.01]) and T2MI [aHR = 2.11 (1.08-4.29)]. FRS did not modify the effect of ABC on MI (P = 0.14) and inclusion of FRS in the MSM did not diminish the effect of recent ABC use on the combined outcome. Conclusions: Recent ABC use was associated with MI after adjustment for known risk factors and for FRS. However, screening for T1MI risks may not identify all or even most persons at risk of ABC use-associated MIs

The roles of the formal and informal sectors in the provision of effective science education

For many years, formal school science education has been criticised by students, teachers, parents and employers throughout the world. This article presents an argument that a greater collaboration between the formal and the informal sector could address some of these criticisms. The causes for concern about formal science education are summarised and the major approaches being taken to address them are outlined. The contributions that the informal sector currently makes to science education are identified. It is suggested that the provision of an effective science education entails an enhanced complementarity between the two sectors. Finally, there is a brief discussion of the collaboration and communication still needed if this is to be effective

Factors Associated with Severity of COVID-19 Disease in a Multicenter Cohort of People with HIV in the United States, March-December 2020

Background: Understanding the spectrum of COVID-19 in people with HIV (PWH) is critical to provide clinical guidance and risk reduction strategies.Setting:Centers for AIDS Research Network of Integrated Clinic System, a US multisite clinical cohort of PWH in care.Methods:We identified COVID-19 cases and severity (hospitalization, intensive care, and death) in a large, diverse HIV cohort during March 1, 2020-December 31, 2020. We determined predictors and relative risks of hospitalization among PWH with COVID-19, adjusted for disease risk scores. Results: Of 16,056 PWH in care, 649 were diagnosed with COVID-19 between March and December 2020. Case fatality was 2%; 106 (16.3%) were hospitalized, and 12 died. PWH with current CD4 count <350 cells/mm3[aRR 2.68; 95% confidence interval (CI): 1.93 to 3.71; P < 0.001] or lowest recorded CD4 count <200 cells/mm3(aRR 1.67; 95% CI: 1.18 to 2.36; P < 0.005) had greater risks of hospitalization. HIV viral load and antiretroviral therapy status were not associated with hospitalization, although most of the PWH were suppressed (86%). Black PWH were 51% more likely to be hospitalized with COVID-19 compared with other racial/ethnic groups (aRR 1.51; 95% CI: 1.04 to 2.19; P = 0.03). Chronic kidney disease, chronic obstructive pulmonary disease, diabetes, hypertension, obesity, and increased cardiovascular and hepatic fibrosis risk scores were associated with higher hospitalization risk. PWH who were older, not on antiretroviral therapy, and with current CD4 count <350 cells/mm3, diabetes, and chronic kidney disease were overrepresented among PWH who required intubation or died. Conclusions: PWH with CD4 count <350 cells/mm3, and a history of CD4 count <200 cells/mm3, have a clear excess risk of severe COVID-19, accounting for comorbidities associated with severe outcomes. PWH with these risk factors should be prioritized for COVID-19 vaccination and early treatment and monitored closely for worsening illness