Mechanical Turk Versus Student Samples: Comparisons and Recommendations

Mechanical Turk and other online crowdsourcing markets (OCMs) have become a go-to data source across scientific disciplines. In 2014 Steelman and colleagues investigated how Mechanical Turk data compared with student samples and consumer panels. They found the data to be comparable and reliable for academic research. In the nearly 10 years since its publication, the use of Mechanical Turk in research has grown substantially. To understand whether their results still hold, we conducted a partial replication to determine how Mechanical Turk workers continue to compare with students using UTAUT 2 as our theoretical model and virtual-reality headsets as the focal IT artifact. Our findings generally align with Steelman et al. (2014) and confirm that Mechanical Turk continues to offer a suitable alternative to student samples. This study reveals consistent results between the student and OCM samples, indicating the potential for interchangeability. The OCM samples are primarily male, while the student sample is majority female, following current US academic trends. All samples are significantly different in age, and only the US OCM and non-US OCM samples are similar in education. The path coefficients from the non-US OCM sample differ significantly from those from other OCM samples; the path coefficients derived from the student sample do not differ significantly from any OCM sample. While sample differences exist, as expected, many are addressable post hoc if anticipated and designed for during data collection. From our findings and the extant literature, we summarize recommendations for researchers and review teams

Ke Ao: A Low-Cost 1U CubeSat for Aerospace Education and Research in Hawaii

The Ke Ao satellite is a low-cost 1U CubeSat designed and developed by an undergraduate team of engineering students at the University of Hawaii at Manoa (UHM) in collaboration with the Hawaii Space Flight Laboratory (HSFL). The primary goal of the mission is to take one or more pictures from space and automatically identify the Hawaiian Islands using Machine Learning Algorithms - this will demonstrate improved onboard operational autonomy in space. A secondary goal of this project is to promote Aerospace Education and Workforce training in Hawaii. The Ke Ao project was inspired by the Hiapo CubeSat initiative of the Hawaii Science and Technology Museum as a unique platform used to provide engaging meaningful hands-on STEM curriculum for Hawaii students K-12. The realization that low-cost flight hardware, in the order of ～$10k, is practically non-existent, and therefore the barrier to launch a flight-capable CubeSat is still high for small organizations and schools with low budgets. The Ke Ao project started in the Fall of 2019 with the Vertically Integrated Project (VIP) Aerospace Technologies with Electrical, Mechanical, and Computer Science Engineering Students at UH and continued to be facilitated under the Mechanical Engineering Senior Design Course within the College of Engineering throughout the year of 2020. The project was impacted by the global COVID-19 pandemic but this enabled the student team to improve on the design and simulations. Hiapo and Ke Ao also inspired the NASA Artemis CubeSat Kit project being developed at the HSFL. The Artemis CubeSat Kit will be used as an educational tool for teaching aerospace and distribution in the public domain. The development of these three CubeSats allowed for synergistic development and multipurpose designs and gave the students a wide breadth of design experiences. This paper will expand on the design and development for the main objectives for Ke Ao (1) take one or more pictures of the Hawaiian Islands from space; (2) cost shall be no more than$10,000 with built parts; and (3) launch-ready via the NASA CSLI application and requirements. To address these objectives Ke Ao uses spaceflight capable but low-cost hardware flown in previous CubeSat missions and consists of seven primary subsystems: Attitude Determination and Control System, Communications, Electrical Power Systems, On-Board Computer and Flight Software, Payload, Structure and Mechanisms, and Thermal Control Systems. Ke Ao will use onboard magnetic torquers to control the attitude of the payload and take pictures of the Hawaiian Islands. The data will be transmitted to the HSFL ground stations in Hawaii and through the SatNOGS ground station network across the World. Ke Ao’s mission and primary goals are in line with the 2018 NASA Strategic Plan’s Strategic Objective 3.3 to Inspire and Engage the Public in Aeronautics, Space, and Science and contribute to the Nation’s science literacy

Selective, Retrieval-Independent Disruption of Methamphetamine-Associated Memory by Actin Depolymerization

Memories associated with drugs of abuse, such as methamphetamine (METH), increase relapse vulnerability to substance use disorder. There is a growing consensus that memory is supported by structural and functional plasticity driven by F-actin polymerization in postsynaptic dendritic spines at excitatory synapses. However, the mechanisms responsible for the long-term maintenance of memories, after consolidation has occurred, are largely unknown

Primary bony non-Hodgkin lymphoma of the cervical spine: a case report

<p>Abstract</p> <p>Introduction</p> <p>Non-Hodgkin lymphoma primarily originating from the bone is exceedingly rare. To our knowledge, this is the first report of primary bone lymphoma presenting with progressive cord compression from an origin in the cervical spine. Herein, we discuss the unusual location in this case, the presenting symptoms, and the management of this disease.</p> <p>Case presentation</p> <p>We report on a 23-year-old Caucasian-American man who presented with two months of night sweats, fatigue, parasthesias, and progressive weakness that had progressed to near quadriplegia. Magnetic resonance (MR) imaging demonstrated significant cord compression seen primarily at C7. Surgical management, with corpectomy and dorsal segmental fusion, in combination with adjuvant chemotherapy and radiation therapy, halted the progression of the primary disease and preserved neurological function. Histological analysis demonstrated an aggressive anaplastic large cell lymphoma.</p> <p>Conclusion</p> <p>Isolated primary bony lymphoma of the spine is exceedingly rare. As in our case, the initial symptoms may be the result of progressive cervical cord compression. Anterior corpectomy with posterolateral decompression and fusion succeeded in preventing progressive neurologic decline and maintaining quality of life. The reader should be aware of the unique presentation of this disease and that surgical management is a successful treatment strategy.</p

Chiral Assemblies of Pinwheel Superlattices on Substrates

The unique topology and physics of chiral superlattices make their self-assembly from nanoparticles a holy grail for (meta)materials. Here we show that tetrahedral gold nanoparticles can spontaneously transform from a perovskite-like low-density phase with corner-to-corner connections into pinwheel assemblies with corner-to-edge connections and denser packing. While the corner-sharing assemblies are achiral, pinwheel superlattices become strongly mirror-asymmetric on solid substrates as demonstrated by chirality measures. Liquid-phase transmission electron microscopy and computational models show that van der Waals and electrostatic interactions between nanoparticles control thermodynamic equilibrium. Variable corner-to-edge connections among tetrahedra enable fine-tuning of chirality. The domains of the bilayer superlattices display strong chiroptical activity identified by photon-induced near-field electron microscopy and finite-difference time-domain simulations. The simplicity and versatility of the substrate-supported chiral superlattices facilitate manufacturing of metastructured coatings with unusual optical, mechanical and electronic characteristics

BET bromodomain proteins regulate enhancer function during adipogenesis

Developmental transitions are guided by master regulatory transcription factors. During adipogenesis, a transcriptional cascade culminates in the expression of PPARγ and C/EBPα, which orchestrate activation of the adipocyte gene expression program. However, the coactivators controlling PPARγ and C/EBPα expression are less well characterized. Here, we show the bromodomain-containing protein, BRD4, regulates transcription of PPARγ and C/EBPα. Analysis of BRD4 chromatin occupancy reveals that induction of adipogenesis in 3T3L1 fibroblasts provokes dynamic redistribution of BRD4 to de novo super-enhancers proximal to genes controlling adipocyte differentiation. Inhibition of the bromodomain and extraterminal domain (BET) family of bromodomain-containing proteins impedes BRD4 occupancy at these de novo enhancers and disrupts transcription of Pparg and Cebpa, thereby blocking adipogenesis. Furthermore, silencing of these BRD4-occupied distal regulatory elements at the Pparg locus by CRISPRi demonstrates a critical role for these enhancers in the control of Pparg gene expression and adipogenesis in 3T3L1s. Together, these data establish BET bromodomain proteins as time- and context-dependent coactivators of the adipocyte cell state transition

Thermoresponsive icy road sign by light scattering and enhanced fluorescence

Prototypes of flexible, electricity-free, ice warning signs for roads and pavements have been developed. A temperature triggered response in the form of an upper critical solution temperature (UCST) type phase separation targeted near the freezing point of water manifests itself through light scattering as a clear-to-opaque transition. It is simultaneously amplified by an enhanced photoluminescence effect. The conceptual road sign application is a multi-lamellar flexible strip with an active layer of a polystyrene-based solution. The solvent is a plasticizer, here either dioctyl phthalate (DOP) or its alternative 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH). A collection of styrene-based macromolecules were made by free radical (co)polymerization, varying molecular weight and monomer feed composition. UCST-type phase diagrams for the polymer solutions were constructed from cloud point data measured with a bespoke photographic set-up, in which up to 30 samples were analyzed simultaneously monitoring both light scattering, in the form of opacity measurements, and fluorescence. For the latter, the concept of restricted motion enhanced photoluminescence, often referred to as aggregation-induced emission (AIE), was used. Polystyrene labelled with tetraphenylethylene (TPE) was used for this. The contrast between ‘ON’ and ‘OFF’ states in the conceptual ice warning signs was optimized by tuning the polymer concentration and the active layer thickness. Our prototype signs show full reversibility over many temperature cycles. We believe the concept can be of wider use in electricity-free signs and labels

Telbivudine versus lamivudine in patients with chronic hepatitis B

BACKGROUND: Reducing hepatitis B virus (HBV) replication to minimal levels is emerging as a key therapeutic goal for chronic hepatitis B. METHODS: In this double-blind, phase 3 trial, 1370 patients with chronic hepatitis B were randomly assigned to receive 600 mg of telbivudine or 100 mg of lamivudine once daily. The primary efficacy end point was noninferiority of telbivudine to lamivudine for therapeutic response (i.e., a reduction in serum HBV DNA levels to fewer than 5 log 10 copies per milliliter, along with loss of hepatitis B e antigen [HBeAg] or normalization of alanine aminotransferase levels). Secondary efficacy measures included histologic response, changes in serum HBV DNA levels, and HBeAg responses. RESULTS: At week 52, a significantly higher proportion of HBeAg-positive patients receiving telbivudine than of those receiving lamivudine had a therapeutic response (75.3% vs. 67.0%, P = 0.005) or a histologic response (64.7% vs. 56.3%, P = 0.01); telbivudine also was not inferior to lamivudine for these end points in HBeAg-negative patients. In HBeAg-positive and HBeAg-negative patients, telbivudine was superior to lamivudine with respect to the mean reduction in the number of copies of HBV DNA from baseline, the proportion of patients with a reduction in HBV DNA to levels undetectable by polymerase-chain-reaction assay, and development of resistance to the drug. Elevated creatine kinase levels were more common in patients who received telbivudine, whereas elevated alanine aminotransferase and aspartate aminotransferase levels were more common in those who received lamivudine. CONCLUSIONS: Among patients with HBeAg-positive chronic hepatitis B, the rates of therapeutic and histologic response at 1 year were significantly higher in patients treated with telbivudine than in patients treated with lamivudine. In both the HBeAg-negative and the HBeAg-positive groups, telbivudine demonstrated greater HBV DNA suppression with less resistance than did lamivudine. (ClinicalTrials.gov number, NCT00057265.) Copyright © 2007 Massachusetts Medical Society.published_or_final_versio

A robust methodology to subclassify pseudokinases based on their nucleotide-binding properties

Protein kinase-like domains that lack conserved residues known to catalyse phosphoryl transfer, termed pseudokinases, have emerged as important signalling domains across all kingdoms of life. Although predicted to function principally as catalysis-independent protein-interaction modules, several pseudokinase domains have been attributed unexpected catalytic functions, often amid controversy. We established a thermal-shift assay as a benchmark technique to define the nucleotide-binding properties of kinase-like domains. Unlike in vitro kinase assays, this assay is insensitive to the presence of minor quantities of contaminating kinases that may otherwise lead to incorrect attribution of catalytic functions to pseudokinases. We demonstrated the utility of this method by classifying 31 diverse pseudokinase domains into four groups: devoid of detectable nucleotide or cation binding; cation-independent nucleotide binding; cation binding; and nucleotide binding enhanced by cations. Whereas nine pseudokinases bound ATP in a divalent cation-dependent manner, over half of those examined did not detectably bind nucleotides, illustrating that pseudokinase domains predominantly function as non-catalytic protein-interaction modules within signalling networks and that only a small subset is potentially catalytically active. We propose that henceforth the thermal-shift assay be adopted as the standard technique for establishing the nucleotide-binding and catalytic potential of kinase-like domains