Students' Beliefs About the Role of Atoms in Radioactive Decay and Half-life

This study investigates students' misconceptions about radioactivity, radioactive decay, and half-life. Individual demonstration interviews and open-response and multiple-choice conceptual tests administered to students from a wide range of science backgrounds show that they are often unable to differentiate between the ideas of irradiation and contamination, and that many of their reasoning difficulties stem from their inaccurate mental models regarding the atom. The author's research indicates that these misconceptions are well-positioned to interfere with students' understanding of how half-life is used to determine geologic time. Educational levels: Graduate or professional

LTE RSRP, RSRQ, RSSNR and local topography profile data for RF propagation planning and network optimization in an urban propagation environment

In the design of 5G cellular communication to guarantee quality signal reception at every point within a coverage area, fundamental knowledge of the channel propagation characteristics is vital. A correct knowledge of electromagnetic wave propagation is required for efficient radio network planning and optimization. Propagation data are used extensively in network planning, particularly for conducting feasibility studies. Hence, measurement of accurate propagation models that predict how the channel varies as people move about is crucial. However, these measured data are often not widely available for channel characterization and propagation model development. In this data article, the Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ) and Reference Signal Signal to Noise Ratio (RSSNR) at various points in space which is covered by a Long-Term Evolution (LTE) marco base station operating at 2100 MHz located in Hatfield, Hertfordshire, United Kingdom were measured. Further, local topography profile data of the study area were extracted from a digital elevation model (DEM) to account for the features of the propagation environment. Correlation matrix and descriptive statistics of the measured LTE data along different routes are analyzed. The RSRP, RSRQ and RSSNR variation with transmitter (Tx) – receiver (Rx) separation distance along the routes are presented. The probability distribution and the DEM of LTE data measurement are likewise presented. The data provided in this article will facilitate research advancement in wireless channel characterization that accounts for local topography features in an urban propagation environment. Moreover, the data sets provided in this article can be extended using simulation-based analysis to extract spatial and temporal channel model parameters in urban cellular environments in the development of 5G channel propagation models.Peer reviewedFinal Published versio

Preferences for Domestic Action Over International Transfers in Global Climate Policy

AbstractCost-effective and equitable climate change mitigation requires the transfer of resources from developed to developing countries. In two behavioral experiments, we demonstrate that American subjects act according to a strong home preference, by making private donations and writing letters in support of public spending more often for mitigation programs located at home versus those overseas. We attempt to overcome the preference to act at home by randomly informing some subjects that foreign programs are more cost-effective than domestic programs. Home preference is mitigated only in the case of private donations. From a separate experimental treatment, we show that the preference against foreign programs is exacerbated when the co-benefits of mitigation programs are made salient. Importantly, home preference crosses party lines, indicating that it is a deep-seeded, affective preference. These findings highlight significant political obstacles to international cooperation on climate change that relies on transfers

An economic evaluation of liquid manure disposal from confinement finishing hogs

Bibliography: p. 28

Dragonflies and damselflies (Odonata) of Colorado: an updated annotated checklist, The

Includes bibliographical references (pages 56-59).February 10, 2015

Stratospheric chemistry and transport

A Chemical Tracer Model (CTM) that can use wind field data generated by the General Circulation Model (GCM) is developed to implement chemistry in the three dimensional GCM of the middle atmosphere. Initially, chemical tracers with simple first order losses such as N2O are used. Successive models are to incorporate more complex ozone chemistry