124 research outputs found

    Student Misconceptions about Plants – A First Step in Building a Teaching Resource

    Get PDF
    Plants are ubiquitous and found in virtually every ecosystem on Earth, but their biology is often poorly understood, and inaccurate ideas about how plants grow and function abound. Many articles have been published documenting student misconceptions about photosynthesis and respiration, but there are substantially fewer on such topics as plant cell structure and growth; plant genetics, evolution, and classification; plant physiology (beyond energy relations); and plant ecology. The available studies of misconceptions held on those topics show that many are formed at a very young age and persist throughout all educational levels. Our goal is to begin building a central resource of plant biology misconceptions that addresses these underrepresented topics, and here we provide a table of published misconceptions organized by topic. For greater utility, we report the age group(s) in which the misconceptions were found and then map them to the ASPB – BSA Core Concepts and Learning Objectives in Plant Biology for Undergraduates, developed jointly by the American Society of Plant Biologists and the Botanical Society of America

    A procedural development for the analysis of <sup>56/54</sup>Fe and <sup>57/54</sup>Fe isotope ratios with new generation IsoProbe MC-ICP-MS

    Get PDF
    We have developed a procedure for iron isotope analysis using a hexapole collision cell MC-ICP-MS which is capable of Fe isotope ratio analysis using two different extraction modes. Matrix effects were minimised and the signal-to-background ratio was maximised using high-concentration samples (~ 5μg Fe) and introducing 1.8 mL/min&lt;sup&gt;-1&lt;/sup&gt; Ar and 2 mL/min H&lt;sub&gt;2&lt;/sub&gt; into the collision cell to decrease polyatomic interferences. The use of large intensity on the faraday cups considerably decreases the internal error of the ratios and ultimately, improves the external precision of a run. Standard bracketing correction for mass bias was possible when using hard extraction. Mass bias in soft extraction mode seems to show temporal instability that makes the standard bracketing inappropriate. The hexapole rf amplitude was decreased to 50 % to further decrease polyatomic interferences and promote the transmission of iron range masses. We routinely measure Fe isotopes with a precision of ± 0.05 ‰ and ± 0.12 ‰ (2σ) for δ&lt;sup&gt;56&lt;/sup&gt;Fe and δ&lt;sup&gt;57&lt;/sup&gt;Fe respectively

    What Undergraduates in Biology Don\u27t Know About Plant Structure and Growth

    Get PDF
    We were interested to know what undergraduates in biology understand about plant structure and growth, and in particular what misconceptions they hold. To date, there has been no comprehensive analysis of what college undergraduates know about this topic, so we designed a study to address this deficiency. Students at two liberal arts colleges, two mid-sized universities (both public and private) and one research university were interviewed one-on-one. They were asked a series of open-ended questions addressing how plants grow taller, grow in diameter, move water and organics, produce leaves, etc. All students had at least one semester of either introductory college biology or introductory plant biology, and most had two. In our preliminary analysis of responses, we see the following trends. The most frequent misconception is that herbaceous tissues are supported entirely by cell walls; the role of water pressure is not comprehended. For some topics, students lack knowledge so completely that they do not even have misconceptions to hold. The mechanism of phloem transport, bark formation and fertilization are in this category. About a third of the interviewees did not know how plants increase in diameter, how leaves form, or how lateral roots form. We have collected data on the specific coursework completed by each student and will also report on correlations between knowledge levels, misconceptions and academic training. Our results should be of use to instructors of both introductory biology and introductory plant biology, as instructors can be more effective if they plan specific learning activities to address misconceptions or topics where student retention of knowledge is poor

    Assessing the feasibility of introducing health insurance in Afghanistan: a qualitative stakeholder analysis

    Get PDF
    Abstract Background In the last decade, the health status of Afghans has improved drastically. However, the health financing system in Afghanistan remains fragile due to high out-of-pocket spending and reliance on donor funding. To address the country’s health financing challenges, the Ministry of Public Health investigated health insurance as a mechanism to mobilize resources for health. This paper presents stakeholders’ opinions on seven preconditions of implementing this approach, as their understanding and buy-in to such an approach will determine its success. Methods Key informant interviews and focus group discussions were conducted with stakeholders. The interviews focused on perceptions of the seven preconditions of introducing health insurance, and adapting a framework developed by the International Labor Organization. Content analysis was conducted after interviews and discussions were transcribed and coded. Results Almost all of the stakeholders from government agencies, the private sector, and development partners are interested in introducing health insurance in Afghanistan, and they were aware of the challenges of the country’s health financing system. Stakeholders acknowledged that health insurance could be an instrument to address these challenges. However, stakeholders differed in their beliefs about how and when to initiate a health insurance scheme. In addition to increasing insecurity in the country, they saw a lack of clear legal guidance, low quality of healthcare services, poor awareness among the population, limited technical capacity, and challenges to willingness to pay as the major barriers to establishing a successful nationwide health insurance scheme. Conclusions The identified barriers prevent Afghanistan from establishing health insurance in the short term. Afghanistan must progressively address these major impediments in order to build a health insurance system

    Symptom Phenotypes in Pulmonary Arterial Hypertension: The PAH “Symptome”

    Get PDF
    Women with pulmonary arterial hypertension (PAH) experience multiple symptoms, including dyspnea, fatigue, and sleep disturbance, that impair their health‐related quality of life (HRQOL). However, we know little about phenotypic subgroups of patients with PAH with similar, concurrent, multiple symptoms. The objectives of this study were to define the “symptome” by symptom cluster phenotypes and compare characteristics such as biomarkers, cardiac structure and function (echocardiography), functional capacity (6‐min walk distance), and HRQOL between the groups. This cross‐sectional study included 60 women with PAH. Subjects completed an assessment battery: Pulmonary Arterial Hypertension Symptom Scale, Pittsburgh Sleep Quality Index, Multidimensional Dyspnea Profile, Patient‐Reported Outcomes Measurement Information System (PROMIS®) Physical Function, PROMIS® Sleep‐Related Impairment, and the emPHasis‐10. Subjects also underwent transthoracic echocardiography, phlebotomy, 6‐min walk distance, and actigraphy. The three symptoms of dyspnea, fatigue, and sleep disturbance were used to define the symptom clusters. Other PAH symptoms, plasma and serum biomarkers, cardiac structure and function (echocardiography), exercise capacity (6‐min walk distance), sleep (actigraphy), and HRQOL were compared across phenotypes. The mean age was 50 ± 18 years, 51% were non‐ Hispanic white, 32% were non‐Hispanic Black and 40% had idiopathic PAH. Cluster analysis identified Mild (n = 28, 47%), Moderate (n = 20, 33%), and Severe Symptom Cluster Phenotypes (n = 12, 20%). There were no differences for age, race, or PAH etiology between the phenotypes. WHO functional class (p \u3c 0.001), norepinephrine levels (p = 0.029), right atrial pressure (p = 0.001), physical function (p \u3c 0.001), sleep onset latency (p = 0.040), and HRQOL (p \u3c 0.001) all differed significantly across phenotypes. We identified three distinctive symptom cluster phenotypes (Mild, Moderate, and Severe) for women with PAH that also differed by PAH‐related symptoms, physical function, right atrial pressure, norepinephrine levels, and HRQOL. These phenotypes could suggest targeted interventions to improve symptoms and HRQOL in those most severely affected

    Tick Extracellular Vesicles Enable Arthropod Feeding and Promote Distinct Outcomes of Bacterial Infection

    Get PDF
    Extracellular vesicles are thought to facilitate pathogen transmission from arthropods to humans and other animals. Here, we reveal that pathogen spreading from arthropods to the mammalian host is multifaceted. Extracellular vesicles from Ixodes scapularis enable tick feeding and promote infection of the mildly virulent rickettsial agent Anaplasma phagocytophilum through the SNARE proteins Vamp33 and Synaptobrevin 2 and dendritic epidermal T cells. However, extracellular vesicles from the tick Dermacentor andersoni mitigate microbial spreading caused by the lethal pathogen Francisella tularensis. Collectively, we establish that tick extracellular vesicles foster distinct outcomes of bacterial infection and assist in vector feeding by acting on skin immunity. Thus, the biology of arthropods should be taken into consideration when developing strategies to control vector-borne diseases

    The James Webb Space Telescope Mission

    Full text link
    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure
    corecore