Differences in beliefs about COVID-19 by gun ownership: a cross-sectional survey of Texas adults

OBJECTIVES: We investigated the association between gun ownership and perceptions about COVID-19 among Texas adults as the pandemic emerged. We considered perceived likelihood that the pandemic would lead to civil unrest, perceived importance of taking precautions to prevent transmission and perceptions that the threat of COVID-19 has been exaggerated. METHODS: Data were collected from 5 to 12 April 2020, shortly after Texas’ stay-at-home declaration. We generated a sample using random digit dial methods for a telephone survey (n=77, response rate=8%) and by randomly selecting adults from an ongoing panel to complete the survey online (n=1120, non-probability sample). We conducted a logistic regression to estimate differences in perceptions by gun ownership. To account for bias associated with use of a non-probability sample, we used Bayesian data integration and ran linear regression models to produce more accurate measures of association. RESULTS: Among the 60% of Texas adults who reported gun ownership, estimates of past 7-day gun purchases, ammunition purchases and gun carrying were 15% (n=78), 20% (n=100) and 24% (n=130), respectively. We found no evidence of an association between gun ownership with perceived importance of taking precautions to prevent transmission or with perceived likelihood of civil unrest. Results from the logistic regression (OR 1.27, 95% CI 0.99 to 1.63) and the linear regression (β=0.18, 95% CI 0.07 to 0.29) suggest that gun owners may be more likely to believe the threat of COVID-19 was exaggerated. CONCLUSIONS: Compared with those without guns, gun owners may have been inclined to downplay the threat of COVID-19 early in the pandemic

Assessing time series models for forecasting international migration : lessons from the United Kingdom

Funding: This work was funded by the Migration Advisory Committee (MAC), UK Home Office, under the Home Office Science contract HOS/14/040, and also supported by the ESRC Centre for Population Change grant ES/K007394/1.Migration is one of the most unpredictable demographic processes. The aim of this article is to provide a blueprint for assessing various possible forecasting approaches in order to help safeguard producers and users of official migration statistics against misguided forecasts. To achieve that, we first evaluate the various existing approaches to modelling and forecasting of international migration flows. Subsequently, we present an empirical comparison of ex post performance of various forecasting methods, applied to international migration to and from the United Kingdom. The overarching goal is to assess the uncertainty of forecasts produced by using different forecasting methods, both in terms of their errors (biases) and calibration of uncertainty. The empirical assessment, comparing the results of various forecasting models against past migration estimates, confirms the intuition about weak predictability of migration, but also highlights varying levels of forecast errors for different migration streams. There is no single forecasting approach that would be well suited for different flows. We therefore recommend adopting a tailored approach to forecasts, and applying a risk management framework to their results, taking into account the levels of uncertainty of the individual flows, as well as the differences in their potential societal impact.Publisher PDFPeer reviewe

Model confidence sets and forecast combination: an application to age-specific mortality

Background: Model averaging combines forecasts obtained from a range of models, and it often produces more accurate forecasts than a forecast from a single model. Objective: The crucial part of forecast accuracy improvement in using the model averaging lies in the determination of optimal weights from a finite sample. If the weights are selected sub-optimally, this can affect the accuracy of the model-averaged forecasts. Instead of choosing the optimal weights, we consider trimming a set of models before equally averaging forecasts from the selected superior models. Motivated by Hansen et al. (2011), we apply and evaluate the model confidence set procedure when combining mortality forecasts. Data & Methods: The proposed model averaging procedure is motivated by Samuels and Sekkel (2017) based on the concept of model confidence sets as proposed by Hansen et al. (2011) that incorporates the statistical significance of the forecasting performance. As the model confidence level increases, the set of superior models generally decreases. The proposed model averaging procedure is demonstrated via national and sub-national Japanese mortality for retirement ages between 60 and 100+. Results: Illustrated by national and sub-national Japanese mortality for ages between 60 and 100+, the proposed model-average procedure gives the smallest interval forecast errors, especially for males. Conclusion: We find that robust out-of-sample point and interval forecasts may be obtained from the trimming method. By robust, we mean robustness against model misspecification

Reactive-based navigation for didactic mobile robot

Artykuł dotyczy systemu nawigacji odruchowej dydaktycznego robota mobilnego MRM.edu. Robot ten powstał w Instytucie Automatyki i Robotyki na Wydziale Mechatroniki Politechniki Warszawskiej. System sterowania pozwala na autonomiczną nawigację odruchową robota. Sposób podejmowania decyzji wzorowany jest na reakcjach organizmów żywych, które pobudzone bodźcem dokonują określonego odruchu. Robot uzyskuje informację o swoim otoczeniu, która staje się dla niego bodźcem do ruchu w odpowiednim kierunku. Specjalnie stworzony algorytm pozwala na poruszanie się wśród przeszkód statycznych oraz dynamicznych, omijanie ich oraz osiągnięcie, początkowo zadanego przez użytkownika, punktu docelowego.This article refers to reactive-based navigation of MRM.edu didactic mobile robot, which was created at the Institute of Automatic Control and Robotics (Mechatronic Faculty, Warsaw University of Technology). Robot has an autonomous reactive-based navigation system. Decision making pattern imitates live organisms, which stimulated with impulse react in particular manner. Robot obtains environmental information and reacts with proper moves to avoid obstacle collision and to achieve destination coordinates. The navigation system needs only specified target, no environmental information such as: maps or technical description are required. This method is particularly effective in new and even not known surrounding. Example application of this system is autonomous search for explosives in dangerous areas, diagnostics in radioactive environment or exploration of hazardous buildings, caves or ruins. Reactive-based navigation is also useful in dynamic changing surrounding, like crowded corridors, when dislocating obstacles can not be described to robot a priori. System reacts to present state of environment and risk of any collision is less probable

Ohio State University – Institute of Aviation undergraduate and Phd student exchange

For years the Ohio State university has been engaged in international academic and research activities. The Institute of Aviation decided to join the ohio State University in this endeavor. The Institute of aviation strongly believes that in order to provide world class research and laboratory services requires world class competitiveness, which is composed of employee knowledge, accredited laboratories, certified processes, modern organization of the workplace. The Ohio State University, and in particular the Propulsion and Power Center, for years, has educated young engineers for the United States Aerospace Industries, and graduates immediately find employment with industry leaders like General Electric, Pratt & Whitney Aircraft, the Boeing Company, and others. The Institute of Aviation, in Warsaw, became also an important Ge business partner with the creation in 2000 of the Engineering Design Center. This position achieved by the Institute of Aviation brought OSU and the Institute to closer cooperation, which started with the jointly organized Polish American Conference on Science and Technology held in 2012 in olumbus, ohio and in 2013 in Washington, d.c. The Institute of Aviation has a long tradition in organizing Polish-American Conferences on Science and Technology. The first conference was held in Washington, d.c. in March 2002, organized together with the Center for Strategic and International Studies (cSIS), a famous Washington based think tank

New drilling technologies used for engineering drilling

Zapotrzebowanie na wiarygodną informację geotechniczną oraz konieczność modyfikacji właściwości gruntów stworzyły w ostatnich latach warunki do modernizacji starych oraz rozwoju nowych technik i technologii wiertniczych. W artykule przedstawiono najnowsze rozwiązania konstrukcyjne i technologiczne, stosowane obecnie na świecie w wierceniach: obrotowych, obrotowo-udarowych i udarowych, formułując kierunki ich dalszego rozwoju. W publikacji skoncentrowano się na porównaniu, niejednokrotnie całkiem odmiennych technologii, umożliwiających odwiercenie i równoczesne orurowanie otworów wiertniczych. Dokonując analizy rozkładu sił w rurach okładzinowych, sprecyzowano warunki wytrzymałościowe, pozwalające na dobór właściwości fizycznych oraz parametrów geometrycznych rurThe necessity to have reliable geotechnical data and also to modify the ground qualities has recently created conditions for modernization of old and development of new drilling techniques and technologies. The newest design and technological solutions used worldwide for rotary, rotary-percussion and percussion drilling condition their further development. Attention was paid to the comparison of frequently different technologies enabling drilling and concurrent tripping of pipes. On the basis of distribution of forces acting in the casing, strength conditions were established, thanks to which the physical and geometrical parameters of pipes can be selecte

Comparative analysis of NEDC and WLTC homologation tests for vehicle tests on a chassis dynamometer

In 2015, the number of vehicles in the world exceeded 1.1 billion units. In the coming years, it is expected that the largest increase in the number of vehicles will take place in developing countries. This is a problem in particular in terms of emissions of harmful substances from vehicles. Considering that all manufactured vehicle models have to undergo a detailed homologation and meet the exhaust emission requirements before placing on the market, it is necessary to refine test procedures, including test cycles, in which vehicle emissions are determined. At present, the NEDC approval test is valid in Europe. It is a cycle reproduced on a chassis dynamometer in steady conditions. It consists of an urban section repeated four times and an extra urban part. From 2019, a new test procedure will take effect, which uses the WLTC cycle, also reproduced on a chassis dynamometer in fixed conditions. It is much more complex and better reflects the real traffic conditions. For a better illustration of the differences that occur between the current NEDC cycle and the new WLTC, the article presents a comparative analysis of both driving cycles. This is to present the justifiability of using a new driving cycle and to present its complexity. The article presents own research of a vehicle with a spark-ignition engine, which has been tested both in the NEDC and WLTC cycle. On the basis of the obtained data, it was possible to determine the differences in the emission of harmful exhaust gas components and indicate how the new homologation procedure affects the emissions from the vehicle

Correlation of parameters describing microstructure of hardened cement slurry for the purpose of increasing tightness of cement mantle

The results of laboratory experiments on fresh cement slurries are presented in this paper. The samples of hardened cement slurry were hydrated for 28 days in wellbore-like conditions and then analyzed for parameters describing their microstructure. The obtained results created a basis for a correlation analysis of parameters of microstructure of hardened cement slurries. The dependences having the big-gest effect on increasing the tightness of the cement mantle were also addressed to