Learning about students’ knowledge and thinking in science through large-scale quantitative studies

2001 ◽  
Vol 16 (3) ◽  
pp. 403-420 ◽  
Author(s):  
Rolf V. Olsen ◽  
Are Turmo ◽  
Svein Lie
2020 ◽  
Vol 31 (2) ◽  
pp. 64-73
Author(s):  
Dinesh Batra

This research note suggests five research challenges when conducting quantitative studies on large-scale agile methodology (LSAM). First, the LSAM empirical literature, which is mainly characterized by qualitative studies primarily focusing on coordination issues, provides limited background. Second, the notion of “large” in LSAM needs to be clarified because the existing research seems to have focused on “very large” or outlier projects. Third, the popular LSAM methods suggest broad and general maxims that may result in difficulty in operationalizing dependent variables, especially in innovation adoption studies. Fourth, the researcher may get overwhelmed when selecting independent variables from the plethora of suggested constructs. Finally, some of the problems associated with large-scale agile are mostly challenges of using conventional agile during a time-period when LSAM had not formally emerged. Researchers should take a balanced approach considering both benefits and challenges of using LSAM and focusing on project-level dependent measures such as success and acceptance.


Author(s):  
Barbara Vis ◽  
Sjoerd Stolwijk

Abstract Conducting quantitative research (e.g., surveys, a large number of interviews, experiments) with the participation of political elites is typically challenging. Given that a population of political elites is typically small by definition, a particular challenge is obtaining a sufficiently high number of observations and, thus, a certain response rate. This paper focuses on two questions related to this challenge: (1) What are best practices for designing the study? And (2) what are best practices for soliciting the participation of political elites? To arrive at these best practices, we (a) examine which factors explain the variation in response rates across surveys within and between large-scale, multi-wave survey projects by statistically analyzing a newly compiled dataset of 342 political elite surveys from eight projects, spanning 30 years and 58 countries, (b) integrate the typically scattered findings from the existing literature and (c) discuss results from an original expert survey among researchers with experience with such research (n = 23). By compiling a comprehensive list of best practices, systematically testing some widely held believes about response rates and by providing benchmarks for response rates depending on country, survey mode and elite type, we aim to facilitate future studies where participation of political elites is required. This will contribute to our knowledge and understanding of political elites’ opinions, information processing and decision making and thereby of the functioning of representative democracies.


2019 ◽  
Vol 12 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Zohra S Lassi ◽  
Zeshi Fisher ◽  
Prabha Andraweera ◽  
Alexandra Cummins ◽  
Claire T Roberts

Abstract Poor infection control practices during childbirth are recognised as a critical factor leading to life-threatening maternal and newborn sepsis. Therefore, this paper assesses the effectiveness of clean birth kits (CBKs) to ensure a safe birthing environment. We searched PubMed, Cochrane Library and CINAHL, as well as Google Scholar, to identify both qualitative and quantitative studies on CBKs published in English up to November 2018. Studies were included if the pregnant women or women giving birth intended to use or used a CBK. The methodological quality of included papers was assessed. A total of 37 studies, 26 quantitative and 11 qualitative studies, were included. Quantitative studies showed a positive impact of CBKs on reducing the incidence of puerperal sepsis and neonatal tetanus. The review also identified CBK use to be associated with a reduction in perinatal, neonatal and young infant mortality. Qualitative studies suggested that a lack of awareness of the importance of CBKs and clean delivery practices, unavailability of CBKs and financial constraints to purchase CBKs were the potential barriers. CBKs appear to be a promising strategy to reduce maternal and neonatal morbidity and mortality. However, the current evidence is limited and further large-scale trials are required.


2018 ◽  
Author(s):  
Lewis E. MacKenzie

1.SummarySince 2004, podcasts have emerged as a decentralised medium for science communication to the global public. However, to-date, there have been no large-scale quantitative studies of the production and dissemination of science podcasts. This study identified 952 English language science podcasts available between January and February 2018 and analysed online textual and visual data related to the podcasts and classified and noted key production parameters. It was found that the total number of science podcast series available grew linearly between 2004 and 2010, and then exponentially between 2010 and 2018. 65% of science podcast series were hosted by scientists and 77% were targeted to public audiences. Although a wide range of primarily single-subject science podcasts series were noted, 34% of science podcast series were not dedicated to a science subject. Compared to biology and physics, chemistry may be under-represented by science podcasts. Only 24% of science podcast series had any overt financial income. 62% of science podcast series were affiliated to an organisation; producing a greater number of episodes (median = 24, average = 96) than independent science podcast series (median = 16, average = 48). This study provides the first ‘snapshot’ of how science podcasts are being used to communicate science to public audiences around the globe.


2020 ◽  
Vol 287 (1935) ◽  
pp. 20201397 ◽  
Author(s):  
C. Marondedze

Post-transcriptional regulation has far-reaching implications on the fate of RNAs. It is gaining increasing momentum as a critical component in adjusting global cellular transcript levels during development and in response to environmental stresses. In this process, RNA-binding proteins (RBPs) are indispensable chaperones that naturally bind RNA via one or multiple globular RNA-binding domains (RBDs) changing the function or fate of the bound RNAs. Despite the technical challenges faced in plants in large-scale studies, several hundreds of these RBPs have been discovered and elucidated globally over the past few years. Recent discoveries have more than doubled the number of proteins implicated in RNA interaction, including identification of RBPs lacking classical RBDs. This review will discuss these new emerging classes of RBPs, focusing on the current state of the RBP repertoire in Arabidopsis thaliana , including the diverse functional roles derived from quantitative studies implicating RBPs in abiotic stress responses. Notably, this review highlights that 836 RBPs are enriched as Arabidopsis RBPs while 1865 can be classified as candidate RBPs. The review will also outline outstanding areas within this field that require addressing to advance our understanding and potential biotechnological applications of RBPs.


Science ◽  
2019 ◽  
Vol 364 (6447) ◽  
pp. 1267-1271 ◽  
Author(s):  
Shaun P. Johnstone ◽  
Andrew J. Groszek ◽  
Philip T. Starkey ◽  
Christopher J. Billington ◽  
Tapio P. Simula ◽  
...  

Nonequilibrium interacting systems can evolve to exhibit large-scale structure and order. In two-dimensional turbulent flow, the seemingly random swirling motion of a fluid can evolve toward persistent large-scale vortices. To explain such behavior, Lars Onsager proposed a statistical hydrodynamic model based on quantized vortices. Here, we report on the experimental confirmation of Onsager’s model. We dragged a grid barrier through an oblate superfluid Bose–Einstein condensate to generate nonequilibrium distributions of vortices. We observed signatures of an inverse energy cascade driven by the evaporative heating of vortices, leading to steady-state configurations characterized by negative absolute temperatures. Our results open a pathway for quantitative studies of emergent structures in interacting quantum systems driven far from equilibrium.


2019 ◽  
Author(s):  
Soichi Hirokawa ◽  
Griffin Chure ◽  
Nathan M. Belliveau ◽  
Geoffrey A. Lovely ◽  
Michael Anaya ◽  
...  

Developing lymphocytes in the immune system of jawed vertebrates assemble antigen-receptor genes by undergoing large-scale reorganization of spatially separated V, D, and J gene segments through a process known as V(D)J recombination. The RAG protein initiates this process by binding and cutting recombination signal sequences (RSSs) composed of conserved heptamer and nonamer sequences flanking less well-conserved 12- or 23-bp spacers. Little quantitative information is known about the contributions of individual RSS positions over the course of the RAG-RSS interaction. We employ a single-molecule method known as tethered particle motion to quantify the formation, stability, and cleavage of the RAG-12RSS-23RSS paired complex (PC) for numerous synthetic and endogenous 12RSSs. We thoroughly investigate the sequence space around a RSS by making 40 different single-bp changes and characterizing the reaction dynamics. We reveal that single-bp changes affect RAG function based on their position: loss of cleavage function (first three positions of the heptamer); reduced propensity for forming the PC (the nonamer and last four bp of the heptamer); or variable effects on PC formation (spacer). We find that the rare usage of some endogenous gene segments can be mapped directly to their adjacent 12RSSs to which RAG binds weakly. The 12RSS, however, cannot explain the high-frequency usage of other gene segments. Finally, we find that RSS nicking, while not required for PC formation, substantially stabilizes the PC. Our findings provide detailed insights into the contribution of individual RSS positions to steps of the RAG-RSS re-action that previously have been difficult to assess quantitatively.SummaryV(D)J recombination is a genomic cut-and-paste process for generating diverse antigen-receptor repertoires. The RAG enzyme brings separate gene segments together by binding the neighboring sequences called RSSs, forming a paired complex (PC) before cutting the DNA. There are limited quantitative studies of the sequence-dependent dynamics of the crucial inter-mediate steps of PC formation and cleavage. Here, we quantify individual RAG-DNA dynamics for various RSSs. While RSSs of frequently-used segments do not comparatively enhance PC formation or cleavage, the rare use of some segments can be explained by their neighboring RSSs crippling PC formation and/or cleavage. Furthermore, PC lifetimes reveal DNA-nicking is not required for forming the PC, but PCs with nicks are more stable.


2007 ◽  
Vol 31 (5) ◽  
pp. 471-479 ◽  
Author(s):  
Shawna J. Dark ◽  
Danielle Bram

Of particular importance to the study of large-scale phenomena in physical geography is the modifiable areal unit problem ( MAUP). While often viewed as only a problem in human geography (particularly demographic studies), the MAUP is an issue for all quantitative studies in geography of spatial phenomena (Openshaw and Taylor, 1979). Increasingly, remote sensing and Geographic Information Systems ( GIS) are being used to assess the distribution of phenomena from a large scale. These phenomena are modelled using areal units that can take any shape or size resulting in complications with statistical analysis related to both the scale and method used to create the areal units. In this paper, we define the modifiable areal unit problem, present examples of when it is a problem in physical geography studies, and review some potential solutions to the problem. Our aim is to increase awareness of this complicated issue and to promote further discussion and interest in this topic.


2018 ◽  
Author(s):  
Jennifer Urban ◽  
Joe Karaganis ◽  
Brianna L. Schofield

In its nearly two decades of existence, the Digital Millennium Copyright Act’s “notice and takedown” process has become both a source of controversy and a primary means of addressing online copyright disputes. Yet there is little empirical research into the use of notice and takedown or its effectiveness. Because it depends on the private communications and actions of copyright holders, online service providers, and targets, notice and takedown operates largely within a difficult-to-study “black box.” This article contributes to the literature with an empirical look at two sets of takedown notices. It digests findings from two quantitative studies of takedown notices in the Lumen database, reported fully in the three-study report, Notice and Takedown in Everyday Practice (available at https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2755628), and peer-reviewed here. The first study, of notices sent to Google Web Search, shows a heavy reliance by large rightsholders on automated infringement detection and notification, and tends to support their assertions that they focus their enforcement resources on large-scale infringement. At the same time, 31% of these notices raised questions related to their accuracy and statutory compliance. The second study provides a snapshot of takedown as used by one set of smaller notice senders — individuals and small businesses sending to Google Image Search. In this study, notices were more likely to target social media sites, blogs, and personal websites, and 70% of the notices raised questions. While both studies revealed surprisingly high percentages of notices of questionable validity, the questions raised tended to differ. The automated notices in the first study predominantly exhibited issues identifying the works in question, while the notices sent by smaller rightsholders in the second study predominantly exhibited issues with the underlying claim. Accordingly, while notice sending appears to need improvement, there is no “one-size-fits-all” approach. Both “worlds” of notice sending need to be accommodated. We therefore suggest a set of voluntary best practices, educational efforts, and modest legal reforms directed to the different issues we observed.


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