Flow and transport from a stream to a well in an unconfined aquifer

Flow, stream depletion rate (SDR), and transport are evaluated with three analytical models for wells installed in a semi-infinite, homogeneous, anisotropic, unconfined aquifer near a fully penetrating stream with a streambed with reduced conductivity. The first model, presented in Maroney and Rehmann (2017), involves re-evaluating the calculations of Huang et al. (2012) for the SDR of a radial collector well. The present solution for SDR has a single integral that requires numerical evaluation, while the previous model has five. Analytical results show that at steady state the flow through the streambed equals the pumping rate of the well. That is, the steady SDR is one, and it does not depend on streambed or aquifer properties or the well design. Before the SDR reaches steady state, streambed conductance, aquifer anisotropy, and the position of the well relative to the stream affect SDR much more than the orientation, length, and depth of the lateral well screens. The second model builds on the method developed for SDR for a radial collector well. It provides flow and SDR for a partially penetrating vertical well installed in a semi-infinite, homogeneous, unconfined aquifer adjacent to a stream with a reduced conductivity streambed. Like the model for SDR of a radial collector well, the SDR for this case has only one improper integral that must be evaluated numerically. Steady drawdown is symmetric across the horizontal plane at the center of the aquifer for a well centered in the aquifer. The supply of water from the stream decreases hydraulic gradients at the top and bottom of the aquifer. The model for a partially penetrating well provides quantitative guidance for practical applications. For example, for removing contaminants, a well with small degree of penetration should be placed near the level of the contamination, and for dewatering—which aims for maximum drawdown and minimum SDR, the well should be placed as high in the aquifer as possible. Streamlines from a river to a nearby well are used to compute the concentration of a contaminant in a well. Concentration at the stream is constant and transport to the well is through advection, retardation, and decay. Both the well and steam fully penetrate the aquifer, which has horizontal anisotropy. The stream has a streambed with reduced conductivity. As shown by dimensional analysis and supporting arguments, the concentration at the well depends on four dimensionless parameters: dimensionless time, a streambed conductance coefficient χ, the ratio κy of the horizontal hydraulic conductivities, and the Damköhler number, which accounts for advection, retardation, and decay by combining the properties of the aquifer, well, and contaminant. For fixed χ and κy, the timing and magnitude of the steady state concentration at the well depend only on the Damköhler number. The special case of no streambed (→∞) yields conservative estimates of the time of first arrival, steady state concentration, and (except for low Damköhler number) the time to steady state

Results from Iowa State Female Graduate Student Needs Assessment Survey, July 2012

During the spring 2012 semester, a task force of graduate students, staff, and faculty created a survey to gather information from women graduate students about their experiences at Iowa State University (ISU). The survey was adapted from similar surveys at MIT and University of Maryland. Our survey had four main sections: (1) Campus climate, (2) Professional development and academic services, (3) Student workload and student services, (4) Wellness, family and housing

Flow and transport from a stream to a well in an unconfined aquifer

Flow, stream depletion rate (SDR), and transport are evaluated with three analytical models for wells installed in a semi-infinite, homogeneous, anisotropic, unconfined aquifer near a fully penetrating stream with a streambed with reduced conductivity. The first model, presented in Maroney and Rehmann (2017), involves re-evaluating the calculations of Huang et al. (2012) for the SDR of a radial collector well. The present solution for SDR has a single integral that requires numerical evaluation, while the previous model has five. Analytical results show that at steady state the flow through the streambed equals the pumping rate of the well. That is, the steady SDR is one, and it does not depend on streambed or aquifer properties or the well design. Before the SDR reaches steady state, streambed conductance, aquifer anisotropy, and the position of the well relative to the stream affect SDR much more than the orientation, length, and depth of the lateral well screens. The second model builds on the method developed for SDR for a radial collector well. It provides flow and SDR for a partially penetrating vertical well installed in a semi-infinite, homogeneous, unconfined aquifer adjacent to a stream with a reduced conductivity streambed. Like the model for SDR of a radial collector well, the SDR for this case has only one improper integral that must be evaluated numerically. Steady drawdown is symmetric across the horizontal plane at the center of the aquifer for a well centered in the aquifer. The supply of water from the stream decreases hydraulic gradients at the top and bottom of the aquifer. The model for a partially penetrating well provides quantitative guidance for practical applications. For example, for removing contaminants, a well with small degree of penetration should be placed near the level of the contamination, and for dewatering—which aims for maximum drawdown and minimum SDR, the well should be placed as high in the aquifer as possible. Streamlines from a river to a nearby well are used to compute the concentration of a contaminant in a well. Concentration at the stream is constant and transport to the well is through advection, retardation, and decay. Both the well and steam fully penetrate the aquifer, which has horizontal anisotropy. The stream has a streambed with reduced conductivity. As shown by dimensional analysis and supporting arguments, the concentration at the well depends on four dimensionless parameters: dimensionless time, a streambed conductance coefficient χ, the ratio κy of the horizontal hydraulic conductivities, and the Damköhler number, which accounts for advection, retardation, and decay by combining the properties of the aquifer, well, and contaminant. For fixed χ and κy, the timing and magnitude of the steady state concentration at the well depend only on the Damköhler number. The special case of no streambed (→∞) yields conservative estimates of the time of first arrival, steady state concentration, and (except for low Damköhler number) the time to steady state.</p

Demographics of new undergraduate medical imaging and medical sonography degree students at CQUniversity, Australia

Aim: To report the student demographics of the inaugural intake into the Bachelor of Medical Imagingand Bachelor of Medical Sonography/Graduate Diploma of Medical Sonography at CQUniversity, Mackay, Australia. Method: Surveys were distributed to students enrolled in the course MEDI11001 Fundamentals of the Imaging Professions; this course is common to both cohorts in Term 1 of the programs. All students enrolled at the time of the survey were present to participate in the survey. Participation was voluntary. Descriptive statistics were developed from responses and thematic analysis applied to open-ended questions. Results: A total of 44 students were enrolled in the programs. The most common place of residence on enrolment was within 40 km of the Mackay campus (16/36.4%); mature age students (30/68.2%); live on campus in the purpose built residences (18/40.9%) and were influenced by the location of the programs in Mackay to enrol (27/61.2%), with the primary justification for this being that the programs were offered close to home. The university website was identified as the primary source of information regarding the programs (15/34.1%) followed by family and friends (11/25%). The programs were first preference for 31 students (70.5%). The majority (23/52.3%) undertakes some type of paid work. Conclusion: Both programs have attracted a diverse student cohort. The majority of students were mature age students from outside of the area local to the Mackay campus of CQUniversity

Results from Iowa State Female Graduate Student Needs Assessment Survey, July 2012

During the spring 2012 semester, a task force of graduate students, staff, and faculty created a survey to gather information from women graduate students about their experiences at Iowa State University (ISU). The survey was adapted from similar surveys at MIT and University of Maryland. Our survey had four main sections: (1) Campus climate, (2) Professional development and academic services, (3) Student workload and student services, (4) Wellness, family and housing.</p

Efficacy and safety of two neutralising monoclonal antibody therapies, sotrovimab and BRII-196 plus BRII-198, for adults hospitalised with COVID-19 (TICO): a randomised controlled trial

We aimed to assess the efficacy and safety of two neutralising monoclonal antibody therapies (sotrovimab [Vir Biotechnology and GlaxoSmithKline] and BRII-196 plus BRII-198 [Brii Biosciences]) for adults admitted to hospital for COVID-19 (hereafter referred to as hospitalised) with COVID-19. In this multinational, double-blind, randomised, placebo-controlled, clinical trial (Therapeutics for Inpatients with COVID-19 [TICO]), adults (aged ≥18 years) hospitalised with COVID-19 at 43 hospitals in the USA, Denmark, Switzerland, and Poland were recruited. Patients were eligible if they had laboratory-confirmed SARS-CoV-2 infection and COVID-19 symptoms for up to 12 days. Using a web-based application, participants were randomly assigned (2:1:2:1), stratified by trial site pharmacy, to sotrovimab 500 mg, matching placebo for sotrovimab, BRII-196 1000 mg plus BRII-198 1000 mg, or matching placebo for BRII-196 plus BRII-198, in addition to standard of care. Each study product was administered as a single dose given intravenously over 60 min. The concurrent placebo groups were pooled for analyses. The primary outcome was time to sustained clinical recovery, defined as discharge from the hospital to home and remaining at home for 14 consecutive days, up to day 90 after randomisation. Interim futility analyses were based on two seven-category ordinal outcome scales on day 5 that measured pulmonary status and extrapulmonary complications of COVID-19. The safety outcome was a composite of death, serious adverse events, incident organ failure, and serious coinfection up to day 90 after randomisation. Efficacy and safety outcomes were assessed in the modified intention-to-treat population, defined as all patients randomly assigned to treatment who started the study infusion. This study is registered with ClinicalTrials.gov, NCT04501978. Between Dec 16, 2020, and March 1, 2021, 546 patients were enrolled and randomly assigned to sotrovimab (n=184), BRII-196 plus BRII-198 (n=183), or placebo (n=179), of whom 536 received part or all of their assigned study drug (sotrovimab n=182, BRII-196 plus BRII-198 n=176, or placebo n=178; median age of 60 years [IQR 50–72], 228 [43%] patients were female and 308 [57%] were male). At this point, enrolment was halted on the basis of the interim futility analysis. At day 5, neither the sotrovimab group nor the BRII-196 plus BRII-198 group had significantly higher odds of more favourable outcomes than the placebo group on either the pulmonary scale (adjusted odds ratio sotrovimab 1·07 [95% CI 0·74–1·56]; BRII-196 plus BRII-198 0·98 [95% CI 0·67–1·43]) or the pulmonary-plus complications scale (sotrovimab 1·08 [0·74–1·58]; BRII-196 plus BRII-198 1·00 [0·68–1·46]). By day 90, sustained clinical recovery was seen in 151 (85%) patients in the placebo group compared with 160 (88%) in the sotrovimab group (adjusted rate ratio 1·12 [95% CI 0·91–1·37]) and 155 (88%) in the BRII-196 plus BRII-198 group (1·08 [0·88–1·32]). The composite safety outcome up to day 90 was met by 48 (27%) patients in the placebo group, 42 (23%) in the sotrovimab group, and 45 (26%) in the BRII-196 plus BRII-198 group. 13 (7%) patients in the placebo group, 14 (8%) in the sotrovimab group, and 15 (9%) in the BRII-196 plus BRII-198 group died up to day 90. Neither sotrovimab nor BRII-196 plus BRII-198 showed efficacy for improving clinical outcomes among adults hospitalised with COVID-19. US National Institutes of Health and Operation Warp Spee