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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.
A national need is to prepare for and respond to accidental or intentional disasters categorized as chemical, biological, radiological, nuclear, or explosive (CBRNE). These incidents require specific subject-matter expertise, yet have commonalities. We identify 7 core elements comprising CBRNE science that require integration for effective preparedness planning and public health and medical response and recovery. These core elements are (1) basic and clinical sciences, (2) modeling and systems management, (3) planning, (4) response and incident management, (5) recovery and resilience, (6) lessons learned, and (7) continuous improvement. A key feature is the ability of relevant subject matter experts to integrate information into response operations. We propose the CBRNE medical operations science support expert as a professional who (1) understands that CBRNE incidents require an integrated systems approach, (2) understands the key functions and contributions of CBRNE science practitioners, (3) helps direct strategic and tactical CBRNE planning and responses through first-hand experience, and (4) provides advice to senior decision-makers managing response activities. Recognition of both CBRNE science as a distinct competency and the establishment of the CBRNE medical operations science support expert informs the public of the enormous progress made, broadcasts opportunities for new talent, and enhances the sophistication and analytic expertise of senior managers planning for and responding to CBRNE incidents.
The Ostrogothic king Theoderic I (a.d. 475–526) drew on his experience of ruling post-imperial Italy when he famously remarked that ‘The poor Roman imitates the Goth and the rich Goth imitates the Roman’. Written well after the fall of the western Roman empire, these words have prefaced many discussions of the process of Roman and barbarian assimilation and mutual acculturation. This topic has long captured the imagination of scholars, who have approached the topic from many different angles, such as archaeology, religion, prosopography and literature.
Although China has had difficulty improving the performance of its banks and stock markets, it has struggled even more to develop a credit rating industry. Credit rating agencies (CRA), which provide bond ratings, are vital to financial markets in advanced capitalist countries, but China's credit rating companies are weak and have had little influence over the behaviour of those who issue or invest in bonds. Some argue that CRAs gain authority through their strong reputation in the eyes of market participants, but the experience of rating agencies in China supports evidence from elsewhere that their private authority is largely dependent on government mandate, a benefit China's CRAs have only recently begun to enjoy. Many private actors, from trade associations to charity groups, are struggling to gain public influence in China, but credit rating agencies may be the best barometer to measure the Chinese government's general stance towards private authority.
White matter fiber pathways are key structural components of the brain and its functional organization. The limbic system carries a great deal of its anatomic connectivity via the cingulum bundle. By allowing the in vivo delineation of the stem of the major fiber pathway systems, diffusion tensor magnetic resonance imaging has opened a new window into the detailed structure of the white matter in health and disease. Topographic, biophysical, and volumetric information about fiber tracts will provide a more complete understanding of the brain. By appreciating its interconnections, the precise anatomical knowledge of the cingulum bundle will improve our understanding of the limbic system and may enable improvements in the assessment and treatment of neuropsychiatric disorders. In this study, the stem of the cingulum bundle was investigated and defined in terms of its trajectory, anisotropy, and volume, in four normal human subjects, using diffusion tensor imaging.
We demonstrate fabrication of periodic arrays of nanometre scale square helices, with potential applications in three-dimensional photonic bandgap (PBG) materials. Processing is performed using a thin film deposition method known as Glancing Angle Deposition (GLAD). Through advanced substrate motion, this technique allows for controlled growth of square helices in a variety of inorganic materials. Organization of the helices into periodic twodimensional geometries is achieved by prepatterning the substrate surface using electron beam lithography. The regular turns of the helices yield periodicity in the third dimension, perpendicular to the substrate. We present studies of tetragonal and trigonal arrays of silicon helices, with lattice constants as low as 300 nm. By deliberately adding or leaving out seeds in the substrate pattern, we have succeeded in engineering line defects. Our periodic nanoscale structure closely matches an ideal photonic band gap architecture, as recently proposed by Toader and John. While our fabrication technique is simpler than most suggested PBG schemes, it is highly versatile. A wide range of materials can be used for GLAD, manipulation of lattice constant and helix pitch ensures optical tunability, and the GLAD films are robust to micromachining.
The purpose of this study was to test the hypothesis that orbitofrontal cortical volume would be reduced following anterior cingulotomy for obsessive-compulsive disorder (OCD). Whole brain cortical parcellation was performed on magnetic resonance imaging (MRI) data from nine patients, before and 9(±6) months following anterior cingulotomy. No significant volumetric reductions were found in the orbitofrontal cortex. Exploratory findings of reduced volume in ventral temporo-fusiform and posterior cingulate regions were consistent with chance differences, in the face of multiple comparisons. Therefore, though the circumscribed lesions of anterior cingulotomy have recently been associated with corresponding volumetric reductions in the caudate nucleus, no comparable volumetric reductions are evident in cortical territories. Taken together, these results are most consistent with a model of cingulo-striatal perturbation as a putative mechanism for the efficacy of this procedure. While limitations in sensitivity may have also contributed to these negative findings, the methods employed have previously proven sufficient to detect cortical volumetric abnormalities in OCD. The current results may reflect a relatively diffuse pattern of cortico-cortical connections involving the neurons at the site of cingulotomy lesions. Future functional neuroimaging studies are warranted to assess possible cortical or subcortical metabolic changes associated with anterior cingulotomy, as well as predictors of treatment response.
We evaluated the efficacy of an ointment containing bacitracin, polymyxin B, and gramicidin for the eradication of colonization by methicillin-resistant Staphylococcus aureus in 11 medical patients, 10 (91%) of whom had previously failed a 1-week course of topical mupirocin. Mupirocin resistance was documented in 5 (45%) of 11 patients. Successful decolonization was achieved in 9 (82%) of 11 patients (based on 2 months of follow-up).
In mid–June 1989, just a couple of weeks after the Tiananmen protests were brought to a halt, a small unit of Peoples Liberation Army soldiers occupied the headquarters of the Stone Group Corporation, then Chinas premier electronics company. The troops were accompanied by a working group composed of Beijing Municipal Communist Party and government officials, who were sent to investigate charges that Stone employees had participated in the crushed student protest movement. Just days before their arrival, three of Stones senior management, including its President, Wan Runnan, had fled China. Wan was one of 21 black hands named by the Communist leadership as having orchestrated the protests.