74 research outputs found
Coordinating IBL and non-IBL Calculus II
Increasing amounts of research support the efficacy of inquiry and projects based learning. However, teaching via inquiry can be challenging for an individual instructor to adopt in a highly coordinated environment where a course is taught by multiple instructors, and all sections are expected to follow a common syllabus and take a common final exam. In this paper, we describe our efforts to make space for an inquiry approach to teaching calculus within this constrained environment where the new approach is not adopted by all instructors. Our efforts started with the collection, adaption and development of materials to cover the topics already defined for the course. We piloted our materials with a small group of instructors in the first semester and then opened up the materials to other instructors in subsequent semesters. We have now implemented this method over the past four semesters. Through this process we have shown that the integration of inquiry methods and projects within the pedagogy of individual instructors can be effective, but efforts should be taken to ensure the timing of instruction and coverage of materials is comparable to the efforts of colleagues teaching via lecture methods
A multi-lake comparative analysis of the General Lake Model (GLM): Stress-testing across a global observatory network
The modelling community has identified challenges for the integration and assessment of lake models due to the diversity of modelling approaches and lakes. In this study, we develop and assess a one-dimensional lake model and apply it to 32 lakes from a global observatory network. The data set included lakes over broad ranges in latitude, climatic zones, size, residence time, mixing regime and trophic level. Model performance was evaluated using several error assessment metrics, and a sensitivity analysis was conducted for nine parameters that governed the surface heat exchange and mixing efficiency. There was low correlation between input data uncertainty and model performance and predictions of temperature were less sensitive to model parameters than prediction of thermocline depth and Schmidt stability. The study provides guidance to where the general model approach and associated assumptions work, and cases where adjustments to model parameterisations and/or structure are required
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Effect of a Virtual Patient Navigation Program on Behavioral Health Admissions in the Emergency Department: A Randomized Clinical Trial
This randomized clinical trial assesses whether the availability of a 45-day behavioral health-virtual patient navigation program decreases hospitalization among adult patients presenting to the emergency department with a behavioral health crisis or need. Importance The number of patients presenting to emergency departments (EDs) for psychiatric care continues to increase. Psychiatrists often make a conservative recommendation to admit patients because robust outpatient services for close follow-up are lacking. Objective To assess whether the availability of a 45-day behavioral health-virtual patient navigation program decreases hospitalization among patients presenting to the ED with a behavioral health crisis or need. Design, Setting, and Participants This randomized clinical trial enrolled 637 patients who presented to 6 EDs spanning urban and suburban locations within a large integrated health care system in North Carolina from June 12, 2017, through February 14, 2018; patients were followed up for up to 45 days. Eligible patients were aged 18 years or older, with a behavioral health crisis and a completed telepsychiatric ED consultation. The availability of the behavioral health-virtual patient navigation intervention was randomly allocated to specific days (Monday through Friday from 7 am to 7 pm) so that, in a 2-week block, there were 5 intervention days and 5 usual care days; 323 patients presented on days when the program was offered, and 314 presented on usual care days. Data analysis was performed from March 7 through June 13, 2018, using an intention-to-treat approach. Interventions The behavioral health-virtual patient navigation program included video contact with a patient while in the ED and telephonic outreach 24 to 72 hours after discharge and then at least weekly for up to 45 days. Main Outcomes and Measures The primary outcome was the conversion of an ED encounter to hospital admission. Secondary outcomes included 45-day follow-up encounters with a self-harm diagnosis and postdischarge acute care use. Results Among 637 participants, 358 (56.2%) were men, and the mean (SD) age was 39.7 (16.6) years. The conversion rates were 55.1% (178 of 323) in the intervention group vs 63.1% (198 of 314) in the usual care group (odds ratio, 0.74; 95% CI, 0.54-1.02; P = .06). The percentage of patient encounters with follow-up encounters having a self-harm diagnosis was significantly lower in the intervention group compared with the usual care group (36.8% [119 of 323] vs 45.5% [143 of 314]; P = .03). Conclusions and Relevance Although the primary result did not reach statistical significance, there is a strong signal of potential positive benefit in an area that lacks evidence, suggesting that there should be additional investment and inquiry into virtual behavioral health programs. Question Does offering virtual patient navigation reduce admission rates for patients presenting to the emergency department with a behavioral health crisis? Findings In this randomized clinical trial, there were fewer admissions on days when the navigation program was available (55.1%) vs on days with usual care (63.1%), although the difference was not statistically significant. Significantly fewer patients who used the navigation program had a follow-up encounter involving a self-harm diagnosis within 45 days compared with patients who received usual care (36.8% vs 45.5%). Meaning Although the primary result did not reach statistical significance, there is a strong signal of potential positive benefit in an area that lacks evidence, suggesting that there should be additional investment and inquiry into this area.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Longâterm population dynamics of dreissenid mussels (Dreissena polymorpha and D. rostriformis): a crossâsystem analysis
Dreissenid mussels (including the zebra mussel Dreissena polymorpha and the quagga mussel D. rostriformis) are among the world's most notorious invasive species, with large and widespread ecological and economic effects. However, their longâterm population dynamics are poorly known, even though these dynamics are critical to determining impacts and effective management. We gathered and analyzed 67 longâterm (>10 yr) data sets on dreissenid populations from lakes and rivers across Europe and North America. We addressed five questions: (1) How do Dreissena populations change through time? (2) Specifically, do Dreissena populations decline substantially after an initial outbreak phase? (3) Do different measures of population performance (biomass or density of settled animals, veliger density, recruitment of young) follow the same patterns through time? (4) How do the numbers or biomass of zebra mussels or of both species combined change after the quagga mussel arrives? (5) How does body size change over time? We also considered whether current data on longâterm dynamics of Dreissena populations are adequate for science and management. Individual Dreissena populations showed a wide range of temporal dynamics, but we could detect only two general patterns that applied across many populations: (1) Populations of both species increased rapidly in the first 1â2 yr after appearance, and (2) quagga mussels appeared later than zebra mussels and usually quickly caused large declines in zebra mussel populations. We found little evidence that combined Dreissena populations declined over the long term. Different measures of population performance were not congruent; the temporal dynamics of one life stage or population attribute cannot generally be accurately inferred from the dynamics of another. We found no consistent patterns in the longâterm dynamics of body size. The longâterm dynamics of Dreissena populations probably are driven by the ecological characteristics (e.g., predation, nutrient inputs, water temperature) and their temporal changes at individual sites rather than following a generalized time course that applies across many sites. Existing longâterm data sets on dreissenid populations, although clearly valuable, are inadequate to meet research and management needs. Data sets could be improved by standardizing sampling designs and methods, routinely collecting more variables, and increasing support
Therapeutic Vaccine for Genital Herpes Simplex Virus-2 Infection: Findings from a Randomized Trial
Background.
Genital herpes simplex virus type 2 (HSV-2) infection causes recurrent lesions and frequent viral shedding. GEN-003 is a candidate therapeutic vaccine containing HSV-2 gD2âTMR and ICP4.2, and Matrix-M2 adjuvant.
Methods.
Persons with genital herpes were randomized into 3 dose cohorts to receive 3 intramuscular doses 21 days apart of 10 ”g, 30 ”g, or 100 ”g of GEN-003, antigens without adjuvant, or placebo. Participants obtained genital swab specimens twice daily for HSV-2 detection and monitored genital lesions for 28-day periods at baseline and at intervals after the last dose.
Results.
One hundred and thirty-four persons received all 3 doses. Reactogenicity was associated with adjuvant but not with antigen dose or dose number. No serious adverse events were attributed to GEN-003. Compared with baseline, genital HSV-2 shedding rates immediately after dosing were reduced with GEN-003 (from 13.4% to 6.4% for 30 Όg [P < .001] and from 15.0% to 10.3% for 100 ”g [P < .001]). Lesion rates were also significantly (P < .01) reduced immediately following immunization with 30 ”g or 100 ”g of GEN-003. GEN-003 elicited increases in antigen binding, virus neutralizing antibody, and T-cell responses.
Conclusions.
GEN-003 had an acceptable safety profile and stimulated humoral and cellular immune responses. GEN-003 at doses of 30 ”g and 100 ”g reduced genital HSV shedding and lesion rates
Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity
The close correspondence between energy intake and expenditure over prolonged time periods, coupled with an apparent protection of the level of body adiposity in the face of perturbations of energy balance, has led to the idea that body fatness is regulated via mechanisms that control intake and energy expenditure. Two models have dominated the discussion of how this regulation might take place. The set point model is rooted in physiology, genetics and molecular biology, and suggests that there is an active feedback mechanism linking adipose tissue (stored energy) to intake and expenditure via a set point, presumably encoded in the brain. This model is consistent with many of the biological aspects of energy balance, but struggles to explain the many significant environmental and social influences on obesity, food intake and physical activity. More importantly, the set point model does not effectively explain the ‘obesity epidemic' - the large increase in body weight and adiposity of a large proportion of individuals in many countries since the 1980s. An alternative model, called the settling point model, is based on the idea that there is passive feedback between the size of the body stores and aspects of expenditure. This model accommodates many of the social and environmental characteristics of energy balance, but struggles to explain some of the biological and genetic aspects. The shortcomings of these two models reflect their failure to address the gene-by-environment interactions that dominate the regulation of body weight. We discuss two additional models - the general intake model and the dual intervention point model - that address this issue and might offer better ways to understand how body fatness is controlled
Combining biomarker and bulk compositional gradient analysis to assess reservoir connectivity
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Organic Geochemistry 41 (2010): 812-821, doi:10.1016/j.orggeochem.2010.05.003.Hydraulic connectivity of petroleum reservoirs represents one of the biggest uncertainties for
both oil production and petroleum system studies. Here, a geochemical analysis involving bulk and
detailed measures of crude oil composition is shown to constrain connectivity more tightly than is
possible with conventional methods. Three crude oils collected from different depths in a single well
exhibit large gradients in viscosity, density, and asphaltene content. Crude oil samples are collected
with a wireline sampling tool providing samples from wellâdefined locations and relatively free of
contamination by drilling fluids; the known provenance of these samples minimizes uncertainties in the
subsequent analysis. The detailed chemical composition of almost the entire crude oil is determined by
use of comprehensive twoâdimensional gas chromatography (GCĂGC) to interrogate the nonpolar
fraction and negative ion electrospray ionization Fourier transform ion cyclotron resonance mass
spectrometry (ESI FTâICR MS) to interrogate the polar fraction. The simultaneous presence of 25â
norhopanes and mildly altered normal and isoprenoid alkanes is detected, suggesting that the reservoir
has experienced multiple charges and contains a mixture of oils biodegraded to different extents. The
gradient in asphaltene concentration is explained by an equilibrium model considering only gravitational
segregation of asphaltene nanoaggregates; this grading can be responsible for the observed variation in
viscosity. Combining these analyses yields a consistent picture of a connected reservoir in which the
observed viscosity variation originates from gravitational segregation of asphaltene nanoaggregates in a
crude oil with high asphaltene concentration resulting from multiple charges, including one charge that
suffered severe biodegradation. Observation of these gradients having appropriate magnitudes
suggests good reservoir connectivity with greater confidence than is possible with traditional techniques
alone.The mass spectrometry work was
supported by the NSF Division of Materials Research through DMRâ06â54118, and the State of Florida
Consequences of gas flux model choice on the interpretation of metabolic balance across 15 lakes
Ecosystem metabolism and the contribution of carbon dioxide from lakes to the atmosphere can be estimated from free-water gas measurements through the use of mass balance models, which rely on a gas transfer coefficient (k) to model gas exchange with the atmosphere. Theoretical and empirically based models of k range in complexity from wind-driven power functions to complex surface renewal models; however, model choice is rarely considered in most studies of lake metabolism. This study used high-frequency data from 15 lakes provided by the Global Lake Ecological Observatory Network (GLEON) to study how model choice of k influenced estimates of lake metabolism and gas exchange with the atmosphere. We tested 6 models of k on lakes chosen to span broad gradients in surface area and trophic states; a metabolism model was then fit to all 6 outputs of k data. We found that hourly values for k were substantially different between models and, at an annual scale, resulted in significantly different estimates of lake metabolism and gas exchange with the atmosphere
Adjunctive rifampicin for Staphylococcus aureus bacteraemia (ARREST): a multicentre, randomised, double-blind, placebo-controlled trial.
BACKGROUND: Staphylococcus aureus bacteraemia is a common cause of severe community-acquired and hospital-acquired infection worldwide. We tested the hypothesis that adjunctive rifampicin would reduce bacteriologically confirmed treatment failure or disease recurrence, or death, by enhancing early S aureus killing, sterilising infected foci and blood faster, and reducing risks of dissemination and metastatic infection. METHODS: In this multicentre, randomised, double-blind, placebo-controlled trial, adults (â„18 years) with S aureus bacteraemia who had received â€96 h of active antibiotic therapy were recruited from 29 UK hospitals. Patients were randomly assigned (1:1) via a computer-generated sequential randomisation list to receive 2 weeks of adjunctive rifampicin (600 mg or 900 mg per day according to weight, oral or intravenous) versus identical placebo, together with standard antibiotic therapy. Randomisation was stratified by centre. Patients, investigators, and those caring for the patients were masked to group allocation. The primary outcome was time to bacteriologically confirmed treatment failure or disease recurrence, or death (all-cause), from randomisation to 12 weeks, adjudicated by an independent review committee masked to the treatment. Analysis was intention to treat. This trial was registered, number ISRCTN37666216, and is closed to new participants. FINDINGS: Between Dec 10, 2012, and Oct 25, 2016, 758 eligible participants were randomly assigned: 370 to rifampicin and 388 to placebo. 485 (64%) participants had community-acquired S aureus infections, and 132 (17%) had nosocomial S aureus infections. 47 (6%) had meticillin-resistant infections. 301 (40%) participants had an initial deep infection focus. Standard antibiotics were given for 29 (IQR 18-45) days; 619 (82%) participants received flucloxacillin. By week 12, 62 (17%) of participants who received rifampicin versus 71 (18%) who received placebo experienced treatment failure or disease recurrence, or died (absolute risk difference -1·4%, 95% CI -7·0 to 4·3; hazard ratio 0·96, 0·68-1·35, p=0·81). From randomisation to 12 weeks, no evidence of differences in serious (p=0·17) or grade 3-4 (p=0·36) adverse events were observed; however, 63 (17%) participants in the rifampicin group versus 39 (10%) in the placebo group had antibiotic or trial drug-modifying adverse events (p=0·004), and 24 (6%) versus six (2%) had drug interactions (p=0·0005). INTERPRETATION: Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S aureus bacteraemia. FUNDING: UK National Institute for Health Research Health Technology Assessment
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