KMS, etc

A general form of the ``Wick rotation'', starting from imaginary-time Green functions of quantum-mechanical systems in thermal equilibrium at positive temperature, is established. Extending work of H. Araki, the role of the KMS condition and of an associated anti-unitary symmetry operation, the ``modular conjugation'', in constructing analytic continuations of Green functions from real- to imaginary times, and back, is clarified. The relationship between the KMS condition for the vacuum with respect to Lorentz boosts, on one hand, and the spin-statistics connection and the PCT theorem, on the other hand, in local, relativistic quantum field theory is recalled. General results on the reconstruction of local quantum theories in various non-trivial gravitational backgrounds from ``Euclidian amplitudes'' are presented. In particular, a general form of the KMS condition is proposed and applied, e.g., to the Unruh- and the Hawking effects. This paper is dedicated to Huzihiro Araki on the occasion of his seventieth birthday, with admiration, affection and best wishes.Comment: 56 pages, submitted to J. Math. Phy

Using theoretical-computational conflicts to enrich the concept name of derivative

Recent literature has pointed out pedagogical obstacles associated with the use of computational environments in the learning of mathematics. In this paper, we focus on the pedagogical role of the computer's inherent limitations in the development of learners' concept images of derivative. In particular, we intend to discuss how the approach to this concept can be designed to prompt a positive conversion of those limitations for the enrichment of concept images. We present results of a case study with six undergraduate students in Brazil, dealing with situation of theoretical-computational conflict

Warm, Trembling, Etc.

Poetry by Fiona Schicho

Flattening the Curve of COVID-19 Vaccine Rejection—A Global Overview

Current levels of public acceptability of immunisation put at serious risk the effectiveness of any future anti-SARS-CoV-2 vaccination programs. High levels of COVID-19 vaccine hesitancy are reported even from countries severely affected by the pandemic. A survey on a representative sample of adult Polish citizens (n=1066) was conducted, showing that 28% of adults in Poland would not vaccinate against SARS-CoV-2 if the vaccine became available. A majority (51%) of the reluctant respondents indicated that their minds would not be changed if given information regarding vaccine safety or efficacy, or if threatened with heavy fines. Significantly fewer respondents (37%) supported COVID-19 vaccinations specifically than supported childhood vaccinations in Poland in general (78% in 2018). Subsequently, a systematic search of nationally representative and methodologically sound surveys identified a total of 20. The vaccine hesitancy for the hypothetical, yet anticipated COVID-19 vaccine varied from very low (2–6% China) to very high (43%, Czechia, and 44%, Turkey). A legislative action, as well as the creation of sound and coherent common international public policies, should precede the availability of effective and safe COVID-19 vaccine. Note: Funding: This research was funded by the joint grant from the Warsaw University and the Medical University of Warsaw Federation Conflict of Interest: We declare no competing interests. Keywords: vaccine, vaccine hesitancy, anti-vaxers, COVID-19, SARS-CoV-

COVID-19 Outbreak Improves Attractiveness of Careers in Medicine in China: A Cross-Sectional Survey in High School Students and Parents

Background: The shortage of healthcare workers is becoming a serious global problem. The underlying reasons may be specific to the healthcare system in each country. Over the past decade, medicine has become an increasingly unpopular profession in China due to the heavy workload, long-term training, and inherent risks. The ongoing COVID-19 pandemic has placed the life-saving roles of healthcare professionals under the spotlight. This public health crisis may have a profound impact on career choices in the young generation of Chinese. Methods: We conducted a questionnaire-based online survey on high school students and their parents from 24 provinces (or municipalities) of China. We investigated the change of interest in medical study due to the outbreak of COVID-19 and the motivational factors. Pearson correlation analysis was used to assess the correlation of static or dynamic interest of medical career selection with the reported number of COVID-19 cases. Maslow’s Hierarchy of Needs was used to explore underlying motivations for selection of medical-related degrees. The logistic regression model was adopted to analyze the main factors associated with students’ choices. Findings: A total of 21,085 students and 21,009 parents were included in the study. We observed an increased preference for medical study since the outbreak of COVID-19 in both students (17·5% to 29·6%) and parents (37·1% to 47·3%). Contribution to society and interest in medicine was rated as the main motivations. Additionally, students who were female, in the resit of graduate year and outside of Hubei province were significantly associated with a keen interest in medical study. Interpretation: This first multi-center cross-sectional study explores the positive change and noble motivations of students’ preferences in medical study during the COVID-19 pandemic. A longitudinal study is required to determine the persistence of their choices. Funding Statement: The Local High Level University Construction Project of Shanghai, China. Declaration of Interests: The authors declare that they have no conflict of interest. Ethics Approval Statement: This study was approved by the Institutional review board of the Fudan University School of Public Health. Informed consent was waived because the questions were answered anonymously

Review on Life Cycle Assessment of Solar Photovoltaic Panels

The photovoltaic (PV) sector has undergone both major expansion and evolution over the last decades, and currently, the technologies already marketed or still in the laboratory/research phase are numerous and very different. Likewise, in order to assess the energy and environmental impacts of these devices, life cycle assessment (LCA) studies related to these systems are always increasing. The objective of this paper is to summarize and update the current literature of LCA applied to different types of grid-connected PV, as well as to critically analyze the results related to energy and environmental impacts generated during the life cycle of PV technologies, from 1st generation (traditional silicon based) up to the third generation (innovative non-silicon based). Most of the results regarded energy indices like energy payback time, cumulative energy demand, and primary energy demand, while environmental indices were variable based on different scopes and impact assessment methods. Moreover, the review work allowed to highlight and compare key parameters (PV type and system, geographical location, efficiency), methodological insights (functional unit, system boundaries, etc.), and energy/environmental hotspots of 39 LCA studies relating to different PV systems, in order to underline the importance of these aspects, and to provide information and a basis of comparison for future analyse

Performance Optimization and Verification of a New Type of Solar Panel for Microsatellites

In this paper, a new method of replacing the conventional honeycomb aluminum panel with 3D metal printing on the microsatellite is presented. The multiobjective optimization method is used to optimize the temperature difference, compression strength, shear strength, and weight of the new type of solar panel structure. The relationships between the structural parameters and optimization targets are established, and the influence of five factors on thermal and structural properties is analyzed. Finally, a group of better structural parameters of the panel is obtained. The relative deviations between simulation analysis and model are 27.45%, 6.12%, 1.365%, and 3.27%, respectively. The optimization results show that the regression model can be used to predict thermal and structural properties of the panel, and the establishment of the model is effective. The analysis results show that the performances can be improved by 91.62%, 46.94%, 17.91%, and 10.28%, respectively. The optimized results are used for 3D metal printing, and the new type of solar panel is obtained. It is proved that the method can effectively improve the thermal and structural properties of the panel and can effectively shorten the development and manufacture cycle of the panel and also reduce the cost. It has high engineering application value