Mechanical Turk (MTurk) is a common source of research participants within the academic community. Despite MTurk's utility and benefits over traditional subject pools some researchers have questioned ...whether it is sustainable. Specifically, some have asked whether MTurk workers are too familiar with manipulations and measures common in the social sciences, the result of many researchers relying on the same small participant pool. Here, we show that concerns about non-naivete on MTurk are due less to the MTurk platform itself and more to the way researchers use the platform. Specifically, we find that there are at least 250,000 MTurk workers worldwide and that a large majority of US workers are new to the platform each year and therefore relatively inexperienced as research participants. We describe how inexperienced workers are excluded from studies, in part, because of the worker reputation qualifications researchers commonly use. Then, we propose and evaluate an alternative approach to sampling on MTurk that allows researchers to access inexperienced participants without sacrificing data quality. We recommend that in some cases researchers should limit the number of highly experienced workers allowed in their study by excluding these workers or by stratifying sample recruitment based on worker experience levels. We discuss the trade-offs of different sampling practices on MTurk and describe how the above sampling strategies can help researchers harness the vast and largely untapped potential of the Mechanical Turk participant pool.
Amazon Mechanical Turk (MTurk) is widely used by behavioral scientists to recruit research participants. MTurk offers advantages over traditional student subject pools, but it also has important ...limitations. In particular, the MTurk population is small and potentially overused, and some groups of interest to behavioral scientists are underrepresented and difficult to recruit. Here we examined whether online research panels can avoid these limitations. Specifically, we compared sample composition, data quality (measured by effect sizes, internal reliability, and attention checks), and the non-naivete of participants recruited from MTurk and Prime Panels—an aggregate of online research panels. Prime Panels participants were more diverse in age, family composition, religiosity, education, and political attitudes. Prime Panels participants also reported less exposure to classic protocols and produced larger effect sizes, but only after screening out several participants who failed a screening task. We conclude that online research panels offer a unique opportunity for research, yet one with some important trade-offs.
The antimicrobial triclosan is used in a wide range of consumer products ranging from toothpaste, cleansers, socks, and baby toys. A bacteriostatic inhibitor of fatty acid synthesis, triclosan is ...extremely stable and accumulates in the environment. Approximately 75% of adults in the United States have detectable levels of the compound in their urine, with a sizeable fraction of individuals (>10%) having urine concentrations equal to or greater than the minimal inhibitory concentration for
and methicillin-resistant
(MRSA). Previous work has identified connections between defects in fatty acid synthesis and accumulation of the alarmone guanosine tetraphosphate (ppGpp), which has been repeatedly associated with antibiotic tolerance and persistence. Based on these data, we hypothesized that triclosan exposure may inadvertently drive bacteria into a state in which they are able to tolerate normally lethal concentrations of antibiotics. Here we report that clinically relevant concentrations of triclosan increased
and MRSA tolerance to bactericidal antibiotics as much as 10,000-fold
and reduced antibiotic efficacy up to 100-fold in a mouse urinary tract infection model. Genetic analysis indicated that triclosan-mediated antibiotic tolerance requires ppGpp synthesis but is independent of growth. These data highlight an unexpected and certainly unintended consequence of adding high concentrations of antimicrobials in consumer products, supporting an urgent need to reevaluate the costs and benefits of the prophylactic use of triclosan and other bacteriostatic compounds.
Maintaining data quality on Amazon Mechanical Turk (MTurk) has always been a concern for researchers. These concerns have grown recently due to the bot crisis of 2018 and observations that past ...safeguards of data quality (e.g., approval ratings of 95%) no longer work. To address data quality concerns, CloudResearch, a third-party website that interfaces with MTurk, has assessed ~165,000 MTurkers and categorized them into those that provide high- (~100,000, Approved) and low- (~65,000, Blocked) quality data. Here, we examined the predictive validity of CloudResearch’s vetting. In a pre-registered study, participants (
N
= 900) from the Approved and Blocked groups, along with a Standard MTurk sample (95% HIT acceptance ratio, 100+ completed HITs), completed an array of data-quality measures. Across several indices, Approved participants (i) identified the content of images more accurately, (ii) answered more reading comprehension questions correctly, (iii) responded to reversed coded items more consistently, (iv) passed a greater number of attention checks, (v) self-reported less cheating and actually left the survey window less often on easily Googleable questions, (vi) replicated classic psychology experimental effects more reliably, and (vii) answered AI-stumping questions more accurately than Blocked participants, who performed at chance on multiple outcomes. Data quality of the Standard sample was generally in between the Approved and Blocked groups. We discuss how MTurk’s Approval Rating system is no longer an effective data-quality control, and we discuss the advantages afforded by using the Approved group for scientific studies on MTurk.
Interactions among host, microbiota and viral pathogens are complex and poorly understood. The goal of the present study is to assess the changes in the skin microbial community of Atlantic salmon ...(Salmo salar L.) in response to experimental infection with salmonid alphavirus (SAV). The salmon skin microbial community was determined using 16S rDNA pyrosequencing in five different experimental groups: control, 7 days after infection with low-dose SAV, 14 days after infection with low-dose SAV, 7 days after infection with high-dose SAV, and 14 days after infection with high-dose SAV. Both infection treatment and time after infection were strong predictors of the skin microbial community composition. Skin samples from SAV3 infected fish showed an unbalanced microbiota characterized by a decreased abundance of Proteobacteria such as Oleispira sp. and increased abundances of opportunistic taxa including Flavobacteriaceae, Streptococcaceae and Tenacibaculum sp. These results demonstrate that viral infections can result in skin dysbiosis likely rendering the host more susceptible to secondary bacterial infections.
Optimal use of whole-exome sequencing (WES) in the pediatric setting requires an understanding of who should be considered for testing and when it should be performed to maximize clinical utility and ...cost-effectiveness.
To investigate the impact of WES in sequencing-naive children suspected of having a monogenic disorder and evaluate its cost-effectiveness if WES had been available at different time points in their diagnostic trajectory.
This prospective study was part of the Melbourne Genomics Health Alliance demonstration project. At the ambulatory outpatient clinics of the Victorian Clinical Genetics Services at the Royal Children's Hospital, Melbourne, Australia, children older than 2 years suspected of having a monogenic disorder were prospectively recruited from May 1 through November 30, 2015, by clinical geneticists after referral from general and subspecialist pediatricians. All children had nondiagnostic microarrays and no prior single-gene or panel sequencing.
All children underwent singleton WES with targeted phenotype-driven analysis.
The study examined the clinical utility of a molecular diagnosis and the cost-effectiveness of alternative diagnostic trajectories, depending on timing of WES.
Of 61 children originally assessed, 44 (21 48% male and 23 52% female) aged 2 to 18 years (mean age at initial presentation, 28 months; range, 0-121 months) were recruited, and a diagnosis was achieved in 23 (52%) by singleton WES. The diagnoses were unexpected in 8 of 23 (35%), and clinical management was altered in 6 of 23 (26%). The mean duration of the diagnostic odyssey was 6 years, with each child having a mean of 19 tests and 4 clinical genetics and 4 nongenetics specialist consultations, and 26 (59%) underwent a procedure while under general anesthetic for diagnostic purposes. Economic analyses of the diagnostic trajectory identified that WES performed at initial tertiary presentation resulted in an incremental cost savings of A$9020 (US$6838) per additional diagnosis (95% CI, A$4304-A$15 404 US$3263-US$11 678) compared with the standard diagnostic pathway. Even if WES were performed at the first genetics appointment, there would be an incremental cost savings of A$5461 (US$4140) (95% CI, A$1433-A$10 557 US$1086- US$8004) per additional diagnosis compared with the standard diagnostic pathway.
Singleton WES in children with suspected monogenic conditions has high diagnostic yield, and cost-effectiveness is maximized by early application in the diagnostic pathway. Pediatricians should consider early referral of children with undiagnosed syndromes to clinical geneticists.
Across much of the Himalaya, rocks in the Lesser Himalayan duplex are covered by roof thrusts of other Paleoproterozoic Lesser Himalayan rocks or Greater Himalayan rocks. However, in central Nepal, ...between the Main Central thrust and the Main Boundary thrust, Lesser Himalayan rocks are exposed in structurally complex relationships within the Lesser Himalayan duplex. We present two balanced cross sections with different stratigraphy involved in the duplex, one with the basal Kuncha Formation and one without this unit, to test stratigraphic assumptions. Both cross sections have roof thrust sheets consisting of the Main Central thrust, Ramgarh‐Munsiari thrust, and Trishuli thrust folded over the hinterland dipping Lesser Himalayan duplex dissected by late faults. Cross section 1 has a shortening estimate from the Main Central thrust to the Main Boundary thrust, including motion on the Main Central thrust, of 359 km or 78%. Cross section 2 has a shortening estimate of 349 km or 76% over the same region. Because the amount and percentage of shortening are not significantly different between the two cross sections, the different stratigraphic assumptions did not change the shortening results. This similarity suggests that many of the choices made when constructing a cross section may be less important than researchers previously thought.
Key Points
Two cross sections of the same surface data have 2% difference in shorteningTotal shortening in the Himalayan thrust belt yields an estimate of 700–1000 kmShortening is 350–1350 km less than predicted for shortening of Greater India
To understand human behavior, social scientists need people and data. In the last decade, Amazon’s Mechanical Turk (MTurk) emerged as a flexible, affordable, and reliable source of human participants ...and was widely adopted by academics. Yet despite MTurk’s utility, some have questioned whether researchers should continue using the platform on ethical grounds. The brunt of their concern is that people on MTurk are financially insecure, subject to abuse, and earn inhumane wages. We investigated these issues with two representative probability surveys of the U.S. MTurk population (
N
= 4094). The surveys revealed: (1) the financial situation of people on MTurk mirrors the general population, (2) most participants do not find MTurk stressful or requesters abusive, and (3) MTurk offers flexibility and benefits that most people value above other options for work. People reported it is possible to earn more than $10 per hour and said they would not trade the flexibility of MTurk for less than $25 per hour. Altogether, our data are important for assessing whether MTurk is an ethical place for research.
Survey respondents who are non-attentive, respond randomly, or misrepresent who they are can impact the outcomes of surveys. Prior findings reported by the CDC have suggested that people engaged in ...highly dangerous cleaning practices during the COVID-19 pandemic, including ingesting household cleaners such as bleach. In our attempts to replicate the CDC's results, we found that 100% of reported ingestion of household cleaners are made by problematic respondents. Once inattentive, acquiescent, and careless respondents are removed from the sample, we find no evidence that people ingested cleaning products to prevent a COVID-19 infection. These findings have important implications for public health and medical survey research, as well as for best practices for avoiding problematic respondents in all survey research conducted online.
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