560 research outputs found

    Accounting for Change: Assessing Top-line Implications of New Revenue Recognition Principles

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    The impending implementation of new FASB guidance regarding the practice of revenue recognition will presumably alter the periodic presentation of top-line business performance. In anticipation of these impacts, this study seeks to isolate contractual business relationships within the automotive supply chain industry in order to illuminate certain changes and make financial statement users aware that corresponding adjustments may have to be made to their perception of revenue results. By outlining the differences between new and historical U.S. GAAP, and applying the anticipated quantitative effects of such shifts within a propositional study, I seek to produce conclusions that investors and analysts can use to better interpret current and future revenue data. Using historical company figures as a basis, incremental influences are applied to disaggregated portions of contract revenue, and final revenue figures are reconstructed to reflect the implications of new accounting guidance. This study displays the potential relative movement of these periodic revenue results as businesses transition away from their established accounting practices and into a new recognition model

    Method for serial passage of infectious hematopoietic necrosis virus (IHNV) in rainbow trout

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    Transmission is a fundamental component of pathogen fitness. A better understanding of pathogen transmission can greatly improve disease management. In particular, controlled studies of multiple rounds of natural transmission (i.e. serial passage) can provide powerful epidemiological and evolutionary inferences. However, such studies are possible in only a few systems because of the challenges in successfully initiating and maintaining transmission in the laboratory. Here we developed an efficient and reproducible cohabitation method for conducting controlled experiments investigating the effects of serial passage on infectious hematopoietic necrosis virus (IHNV) in rainbow trout. This method was used to investigate the transmission efficiency and kinetics of viral shedding of IHNV over 3 serial passages. Transmission efficiency decreased from 100 to 62.5% over the passage steps and was associated with a decrease in virus shedding into water. A shift in the peak of viral shedding was also observed, from Day 2 post immersion for passage 0 to at least 24 h later for all subsequent passages. Finally, the characterization of viruses after 1 round of transmission and propagation on cells showed no change in glyco protein (G gene) sequences or viral virulence compared to the ancestral virus stock. The methods developed provide valuable tools for reproducible population-level studies of IHNV epidemiology and evolution

    Analysis of Microtubule Sliding Patterns in Chlamydomonas Flagellar Axonemes Reveals Dynein Activity on Specific Doublet Microtubules

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    Generating the complex waveforms characteristic of beating eukaryotic cilia and flagella requires spatial regulation of dynein-driven microtubule sliding. To generate bending, one prediction is that dynein arms alternate between active and inactive forms on specific subsets of doublet microtubules. Using an in vitro microtubule sliding assay combined with a structural approach, we determined that ATP induces sliding between specific subsets of doublet microtubules, apparently capturing one phase of the beat cycle. These studies were also conducted using high Ca2+ conditions. InChlamydomonas, high Ca2+ induces changes in waveform which are predicted to result from regulating dynein activity on specific microtubules. Our results demonstrate that microtubule sliding in high Ca2+ buffer is also induced by dynein arms on specific doublets. However, the pattern of microtubule sliding in high Ca2+ buffer significantly differs from that in low Ca2+. These results are consistent with a ‘switching hypothesis’ of axonemal bending and provide evidence to indicate that Ca2+ control of waveform includes modulation of the pattern of microtubule sliding between specific doublets. In addition, analysis of microtubule sliding in mutant axonemes reveals that the control mechanism is disrupted in some mutants

    Incorporating Science and Engineering Practices Into Preservice Secondary Science Teachers’ Planning Practices: Testing the Efficacy of an Intervention

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    The New Standards Framework (NRC, 2012) explicitly calls for teachers to engage students in science and engineering practices (SEPs) as they develop knowledge of scientific phenomena and canonical disciplinary ideas. This study analyzed six pre-service secondary science teachers’ (PSSSTs’) incorporation of SEPs into their planning practices before, during, and after an instructional intervention. The intervention, which was nested into an instructional methods course, supported the PSSSTs by representing the practices they were to engage their own students with. The PSSSTs were then able to decompose and approximate those scientific practices in their lesson planning, thereby developing pedagogical design capacity (PDC). The PSSSTs were interviewed to determine what affordances and constraints they felt when planning for incorporating SEPs into their lesson planning. Analysis of the lesson plans showed that 50% of the PSSSTs incorporated SEPs into their lesson plans when only provided a written description of the SEPs and prompted to do so. During the instructional intervention, 83% of the PSSSTs incorporated SEPs into their lesson plans. After the instructional intervention, the PSSSTs were no longer required to incorporate SEPs into their lesson planning nor were they required to hand in lesson plans for a grade. Instead, they wrote lesson plans for their cooperating teachers and for their own use. Surprisingly, the PSSSTs not only continued to incorporate SEPs into their lessons, but did so more completely by incorporating a diversity of sub-SEPs and more of them in their lessons. This is significant because this may indicate that the instructional intervention has longevity. Interview data suggests that PSSSTs experience both internal and external affordances and constrains when attempting to incorporate SEPs into their lesson planning. Three categories of issues (epistemic, logistical, and curricular) emerged in the results and influence how teachers interact with the SEPs as they plan lessons. This study reiterates the need for teacher educators to engage in instruction that represents aspects of scientific practice, allows for its decomposition, and engages pre-service teachers in approximating those practices

    You Look So Good for Your Age: First Steps of Creating a Measure of Daily Experiences of Ageism

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    Ageism refers to the combined stereotypes, prejudice, and discriminatory behaviors based on someone’s presumed age. Older adults are viewed with mixed (ambivalent) perceptions, such that they are viewed as being warm, but not very capable. Thus, there are multiple forms of ageism. Hostile ageism refers to the overtly negative ageism, whereas benevolent ageism refers to the seemingly kind form of ageism that still reinforces negative stereotypes (e.g., giving your seat to someone, assuming they are fragile or weak). Most research on ageism has referred to attitudes, both inter-and intra-group, directed toward older adults and aging. This work has found that hostile attitudes and views of aging predict worse health and well-being, totaling a cost of up to $63 billion per year (Levy et al., 2020). However, little research has examined how ageism is experienced across a lifespan sample (younger, middle aged, and older adults) and presently no current research has examined how ageism is experienced in a daily diary method. The goal of our research is to create a way to measure daily experiences of ageism to use in a future daily diary study

    Limited available evidence supports theoretical predictions of reduced vaccine efficacy at higher exposure dose

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    Understanding the causes of vaccine failure is important for predicting disease dynamics in vaccinated populations and planning disease interventions. Pathogen exposure dose and heterogeneity in host susceptibility have both been implicated as important factors that may reduce overall vaccine efficacy and cause vaccine failure. Here, we explore the effect of pathogen dose and heterogeneity in host susceptibility in reducing efficacy of vaccines. Using simulation-based methods, we find that increases in pathogen exposure dose decrease vaccine efficacy, but this effect is modified by heterogeneity in host susceptibility. In populations where the mode of vaccine action is highly polarized, vaccine efficacy decreases more slowly with exposure dose than in populations with less variable protection. We compared these theoretical results to empirical estimates from a systematic literature review of vaccines tested over multiple exposure doses. We found that few studies (nine of 5,389) tested vaccine protection against infection over multiple pathogen challenge doses, with seven studies demonstrating a decrease in vaccine efficacy with increasing exposure dose. Our research demonstrates that pathogen dose has potential to be an important determinant of vaccine failure, although the limited empirical data highlight a need for additional studies to test theoretical predictions on the plausibility of reduced host susceptibility and high pathogen dose as mechanisms responsible for reduced vaccine efficacy in high transmission settings

    Immune-mediated competition in rodent malaria is most likely caused by induced changes in innate immune clearance of merozoites

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    Malarial infections are often genetically diverse, leading to competitive interactions between parasites. A quantitative understanding of the competition between strains is essential to understand a wide range of issues, including the evolution of virulence and drug resistance. In this study, we use dynamical-model based Bayesian inference to investigate the cause of competitive suppression of an avirulent clone of Plasmodium chabaudi (AS) by a virulent clone (AJ) in immuno-deficient and competent mice. We test whether competitive suppression is caused by clone-specific differences in one or more of the following processes: adaptive immune clearance of merozoites and parasitised red blood cells (RBCs), background loss of merozoites and parasitised RBCs, RBC age preference, RBC infection rate, burst size, and within-RBC interference. These processes were parameterised in dynamical mathematical models and fitted to experimental data. We found that just one parameter μ, the ratio of background loss rate of merozoites to invasion rate of mature RBCs, needed to be clone-specific to predict the data. Interestingly, μ was found to be the same for both clones in single-clone infections, but different between the clones in mixed infections. The size of this difference was largest in immuno-competent mice and smallest in immuno-deficient mice. This explains why competitive suppression was alleviated in immuno-deficient mice. We found that competitive suppression acts early in infection, even before the day of peak parasitaemia. These results lead us to argue that the innate immune response clearing merozoites is the most likely, but not necessarily the only, mediator of competitive interactions between virulent and avirulent clones. Moreover, in mixed infections we predict there to be an interaction between the clones and the innate immune response which induces changes in the strength of its clearance of merozoites. What this interaction is unknown, but future refinement of the model, challenged with other datasets, may lead to its discovery

    A missing dimension in measures of vaccination impacts

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    Immunological protection, acquired from either natural infection or vaccination, varies among hosts, reflecting underlying biological variation and affecting population-level protection. Owing to the nature of resistance mechanisms, distributions of susceptibility and protection entangle with pathogen dose in a way that can be decoupled by adequately representing the dose dimension. Any infectious processes must depend in some fashion on dose, and empirical evidence exists for an effect of exposure dose on the probability of transmission to mumps-vaccinated hosts [1], the case-fatality ratio of measles [2], and the probability of infection and, given infection, of symptoms in cholera [3]. Extreme distributions of vaccine protection have been termed leaky (partially protects all hosts) and all-or-nothing (totally protects a proportion of hosts) [4]. These distributions can be distinguished in vaccine field trials from the time dependence of infections [5]. Frailty mixing models have also been proposed to estimate the distribution of protection from time to event data [6], [7], although the results are not comparable across regions unless there is explicit control for baseline transmission [8]. Distributions of host susceptibility and acquired protection can be estimated from dose-response data generated under controlled experimental conditions [9]–[11] and natural settings [12], [13]. These distributions can guide research on mechanisms of protection, as well as enable model validity across the entire range of transmission intensities. We argue for a shift to a dose-dimension paradigm in infectious disease science and community health

    Des Moines Area Community College Creative Writing Contest 1976-2001

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    Award-Winning Works For the Academic Year · 2000-2001https://openspace.dmacc.edu/creativewriting/1002/thumbnail.jp
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