There is limited convincing quantitative data on the export of used electronics from the United States (U.S.). Thus, we advance a methodology to quantify the export flows of whole units of used electronics from the U.S. using detailed export trade data, and demonstrate the methodology using laptops. Since used electronics are not explicitly identified in export trade data, we hypothesize that exports with a low unit value below a used-new threshold specific to a destination world region are used. The importance of using the most disaggregated trade data set available when resolving used and new goods is illustrated. Two detailed U.S. export trade data sets were combined to arrive at quantities and unit values for each port, mode of transport, month, trade partner country, and trade code. We add rigor to the determination of the used-new threshold by utilizing both the Neighborhood valley-emphasis method (NVEM) and published sales prices. This analysis found that 748 to 1199 thousand units of used laptops were exported from the U.S. in 2010, of which 78-81% are destined for non-OECD countries. Asia was found to be the largest destination of used laptop exports across all used-new threshold methods. Latin American and the Caribbean was the second largest recipient of these exports. North America and Europe also received used laptops from the U.S. Only a small fraction of used laptops was exported to Africa. However, these quantities are lower bound estimates because not all shipments of used laptops may be shipped using the proper laptop trade code. Still, this approach has the potential to give insight into the quantity and destinations of the exports if applied to all used electronics product types across a series of years.
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Nat Commun
December 2024
Anthropology Department, University of California Santa Cruz, Santa Cruz, CA, USA.
Strontium isotope (Sr/Sr) analysis with reference to strontium isotope landscapes (Sr isoscapes) allows reconstructing mobility and migration in archaeology, ecology, and forensics. However, despite the vast potential of research involving Sr/Sr analysis particularly in Africa, Sr isoscapes remain unavailable for the largest parts of the continent. Here, we measure the Sr/Sr ratios in 778 environmental samples from 24 African countries and combine this data with published data to model a bioavailable Sr isoscape for sub-Saharan Africa using random forest regression.
View Article and Find Full Text PDFNetw Neurosci
December 2024
Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY, USA.
The integration-segregation framework is a popular first step to understand brain dynamics because it simplifies brain dynamics into two states based on global versus local signaling patterns. However, there is no consensus for how to best define the two states. Here, we map integration and segregation to order and disorder states from the Ising model in physics to calculate state probabilities, and , from functional MRI data.
View Article and Find Full Text PDFBackground: This paper aims to inform practice for educational psychologists and other professionals who seek to facilitate youth participatory action research (YPAR) in schools. Youth participatory action research is founded on the assumption that young people are capable of being researchers who can co-create knowledge and act to change the world. It is a worldview as well as a research approach and can be initiated to co-produce knowledge, facilitate critical thinking, promote the evaluation of social systems and/or act against social oppression.
View Article and Find Full Text PDFJ Environ Manage
December 2024
School of Management and Economics, Beijing Institute of Technology, Beijing, 100081, China; Faculty of Economics, Namdinh University of Technology Education, Namdinh, 07113, Viet Nam.
Ecological footprint (EF) is a useful tool for benchmarking environmental performance and monitoring progress toward a sustainable future. The influence of economic, developmental, and governance factors on EF poses a significant threat to ecological balance. However, existing studies have largely overlooked the interactive relationships among these factors and their impacts on the EF across different regions.
View Article and Find Full Text PDFSci Rep
December 2024
School of Big Data, Fuzhou University of International Studies and Trade, Fuzhou, 350202, China.
The traditional machine learning methods such as decision tree (DT), random forest (RF), and support vector machine (SVM) have low classification performance. This paper proposes an algorithm for the dry bean dataset and obesity levels dataset that can balance the minority class and the majority class and has a clustering function to improve the traditional machine learning classification accuracy and various performance indicators such as precision, recall, f1-score, and area under curve (AUC) for imbalanced data. The key idea is to use the advantages of borderline-synthetic minority oversampling technique (BLSMOTE) to generate new samples using samples on the boundary of minority class samples to reduce the impact of noise on model building, and the advantages of K-means clustering to divide data into different groups according to similarities or common features.
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