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Amazon's Mechanical Turk is widely used for data collection; however, data quality may be declining due to the use of virtual private servers to fraudulently gain access to studies. Unfortunately, we know little about the scale and consequence of this fraud, and tools for social scientists to detect and prevent this fraud are underdeveloped. We first analyze 38 studies and show that this fraud is not new, but has increased recently. We then show that these fraudulent respondents provide particularly low-quality data and can weaken treatment effects. Finally, we provide two solutions: an easy-to-use application for identifying fraud in the existing datasets and a method for blocking fraudulent respondents in Qualtrics surveys.
External aortic compression (EAC) has long been used to control exsanguinating post-partum hemorrhage, but it has only recently been described in the prehospital trauma setting. This paper reports four cases where manual EAC was used during transport to manage life-threatening bleeding, twice from stab wounds, once from ruptured ectopic pregnancy, and once from severe lower-limb trauma. It showed that EAC has life-saving potential in the prehospital setting, but that safety and efficacy during transport requires the use of a hands-free compression device, such as an aortic tourniquet.
The archaeology of the nineteenth-century Chinese diaspora is a well-developed archaeological subfield, but research on Chinese migrants’ homelands is lacking. Survey of a qiaoxiang (home village) in China's Pearl River Delta provides the first archaeological evidence from a home village of Chinese migrants. Transnational comparative analysis with collections recovered from Chinese diaspora settlements reveals stark differences in the use of China-produced goods between qiaoxiang and Chinese settlements abroad. Qiaoxiang residents primarily used locally produced ceramics, while residents of Chinese diaspora settlements consumed ceramics produced in Gaobei and Jingdezhen, major pottery centers located in northeast Guangdong Province and Jiangxi Province, hundreds of kilometers to the north. Additionally, qiaoxiang residents were engaged in global networks of consumption, using British refined earthenwares and other products produced in Europe and the United States. These findings challenge the common assumption made in diaspora research that artifacts produced in migrants’ homelands are evidence of tradition, while those produced in migrants’ adopted countries are evidence of culture change. Instead, the results of qiaoxiang archaeology indicate the significance of nonstate actors, especially import-export companies, in shaping the material worlds of both homeland and diaspora communities. (Spanish abstract available as Supplemental Text 1.)
In species that aggregate for reproduction, the social and fitness costs of movement between groups frequently lead to restricted exchange between breeding areas. We report on four individual humpback whales identified in both the Cape Verde Islands and Guadeloupe; locations separated by an ocean basin and >4000 km. This rate of exchange is rarely encountered between such geographically discrete breeding areas. Two individuals returned to the area where they were originally identified. In contrast, no individuals from the Cape Verde Islands were resighted to the much larger sample from the Dominican Republic, though the migratory distances from the feeding areas are comparable between these areas. The social factors driving the stark difference between groups that is observed here are not clear. Effective conservation requires an understanding of the extent and pattern of movement between population units. The findings presented here suggest that there may well be more than one behaviourally distinct group within the West Indies. More broadly, they argue that considerable caution is warranted in assumptions made regarding the number, boundaries and status of population units based solely on spatial separation or proximity.
This article advocates a lesson plan for introductory comparative politics and elections courses. The authors argue that Wikipedia (yes, Wikipedia) provides a unique platform for improving learning outcomes and a useful social good from traditional student papers on elections. The proposed lesson plan can achieve this in at least three ways: (1) by providing social incentives for learning and a method for students to contribute to social science knowledge from their earliest courses, the incorporation of Wikipedia editing can improve student learning and retention; (2) incorporating an online information component can help both future students and researchers by improving the quality and quantity of easily accessible and well-referenced information about historical and upcoming elections; and (3) the use of the Wiki format is becoming increasingly common in both business and government. Teaching the basics of editing is an increasingly useful skill for students to learn for future employment.
The Deltatrac™ II Metabolic Monitor (Datex-Ohmeda Inc.) is considered the standard reference machine in indirect calorimetry; however, it is no longer commercially available thus there is a need for new machines. The gas exchange measurement (GEM; GEM Nutrition Ltd) and the ECAL (Health Professional Solutions) are alternative measuring systems. The aim of this study was to compare the ECAL and GEM with Deltatrac for measures of RMR and the GEM to the Deltatrac for measures of diet-induced thermogenesis (DIT). Twenty healthy participants were tested on test day 1 (T1) and test day 2 (T2). RMR was measured in a randomised order for 30 min on the Deltatrac, the GEM and the ECAL. Following this, a 1553 kJ meal was consumed and DIT was measured on the Deltatrac and the GEM in alternating 15 min intervals for 4 h. The GEM reported consistently higher values than the Deltatrac for VO2, VCO2, RMR and fat oxidation (P < 0·005). The ECAL was significantly higher than the Deltatrac for measures of VO2, RMR, carbohydrate oxidation (T2) and respiratory quotient and fat oxidation (T1, T2) (P < 0·05). There were no significant differences within repeated RMR measures on the ECAL, the GEM or the Deltatrac. DIT measures were consistently higher on the GEM (T1) (P < 0·005); however, there were no significant differences between repeated measures. The findings suggest that while the GEM and the ECAL were not accurate alternatives to the Deltatrac, they may be reliable for repeated measures.
Zoophycos-group burrows are prevalent elements of the post-Cambrian trace fossil record. Here we report the oldest specimens of Zoophycos from Lower Cambrian strata of the Lower Member Wood Canyon Formation in southeastern California. In addition to these being the oldest examples of this well-known trace fossil, the discovery of these specimens also reveals the presence of deposit feeding considerably earlier than has been suggested for the advent of this feeding style. This type of activity may have had a significant impact on sediment mixing during the Precambrian–Cambrian transition, though the rarity and shallow tier position of these specimens suggests otherwise.
Interest in deliberative theories of democracy has grown tremendously among political theorists, political scientists, activists, and even government officials. Many scholars, however, are skeptical that it is a practically viable theory, even on its own terms. They argue (inter alia) that most people dislike politics and that deliberative initiatives would amount to a paternalistic imposition. Using two large national samples investigating people's hypothetical willingness to deliberate and their actual participation in response to a real invitation to deliberate with their member of Congress, we find that (1) willingness to deliberate in the United States is much more widespread than expected, and (2) it is precisely those people less likely to participate in traditional partisan politics who are most interested in deliberative participation. They are attracted to such participation as a partial alternative to “politics as usual.”
Diffusion tensor imaging was used to investigate white matter (WM) integrity in adults with traumatic brain injury (TBI) and healthy adults as controls. Adults with TBI had sustained severe vehicular injuries on the average of 7 years earlier. A multivariate analysis of covariance with verbal IQ as the covariate revealed that adults with TBI had lower fractional anisotropy and higher mean diffusivity than controls, specifically in the three regions of interest (ROIs), the centrum semiovale (CS), the superior frontal (SPF), and the inferior frontal (INF). Adults with TBI averaged in the normal range in motor speed and two of three executive functions and were below average in delayed verbal recall and inhibition, whereas controls were above average. Time since injury, but not age, was associated with WM changes in the SPF ROI, whereas age, but not time since injury, was associated with WM changes in the INF ROI, suggesting that the effects of WM on time since injury may interact with age. To understand the utility of WM changes in chronic recovery, larger sample sizes are needed to investigate associations between cognition and WM integrity of severely injured individuals who have substantial cognitive impairment compared to severely injured individuals with little cognitive impairment. (JINS, 2009, 15, 130–136.)
Pulse diffusion has been used for doping GaAs n-type to over 1019 cm−3. Surface arsenic loss is avoided through using As2Se3 as the diffusion source. A reduction in electrical activity similar to that reported for pulse annealed implanted layers occurs with any subsequent heat treatment. A resistive region, found at the surface of the profile, can be circumvented through additionally heating the GaAs thermally during the pulse diffusion and reducing the rapidity of the quench.
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