Physical properties of Class I methanol masers

2017 ◽  
Vol 13 (S336) ◽  
pp. 17-22 ◽  
Author(s):  
Silvia Leurini ◽  
Karl M. Menten
Keyword(s):  
Physical Properties ◽  
Recent Progress ◽  
Class Ii ◽  
Point Of View ◽  
Class I ◽  
Theoretical Point ◽  
The Past ◽  
Methanol Masers

AbstractAs first realised in the late 1980s, methanol masers come in two varieties, termed Class I and Class II. While Class II masers had observationally been extensively studied in the past, until recently relatively little attention was paid to Class I methanol masers due to their low luminosities compared to other maser transitions. In this review, we will focus on the recent progress in our understanding of Class I methanol masers both from an observational and from a theoretical point of view.

scholarly journals Class I and Class II methanol masers in high-mass star-forming regions

2010 ◽  
Vol 517 ◽  
pp. A56 ◽  
Author(s):  
F. Fontani ◽  
R. Cesaroni ◽  
R. S. Furuya
Keyword(s):  
Class Ii ◽  
Class I ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Methanol Masers

scholarly journals Twinning in MAPbI3 at room temperature uncovered through Laue neutron diffraction

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Joachim Breternitz ◽  
Michael Tovar ◽  
Susan Schorr
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Neutron Diffraction ◽  
Room Temperature ◽  
Point Of View ◽  
Temperature Structure ◽  
Theoretical Point ◽  
Laue Diffraction ◽  
The Past ◽  
Halide Perovskites

Abstract The crystal structure of MAPbI3, the signature compound of the hybrid halide perovskites, at room temperature has been a reason for debate and confusion in the past. Part of this confusion may be due to twinning as the material bears a phase transition just above room temperature, which follows a direct group–subgroup relationship and is prone to twinning. Using neutron Laue diffraction, we illustrate the nature of twinning in the room temperature structure of MAPbI3 and explain its origins from a group-theoretical point-of-view.

scholarly journals SPATIAL DETERMINISM AND TERRITORIAL PUBLIC ACTION IN FRANCE: CHALLENGES AND EVOLUTIONS

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Grégory BUSQUET
Keyword(s):  
Point Of View ◽  
Theoretical Point ◽  
Spatial Transformation ◽  
The Past ◽  
Urban Narrative ◽  
The People ◽  
Strategic Approach ◽  
Urban Project ◽  
The City

This article proposes a theoretical point of view in order to show the importance of the collective memory and the urban narrative in the strategic approach of the urban project. The capacity of a municipality to build a local narrative joining the past, the memory and the project, is examined in the second part of the article, in a case study of a collectivity confronted with the project of the Grand Paris and strong socio-spatial transformation since 1950. The conclusions of thirty deep interviews, conducted on the people involved in the city organization allow to differentiate legitimated and rejected places in the spaces of remembering, and the difficulties of this kind of municipalities to be pro active in the Grand Paris project.

scholarly journals The comparative method for policy studies: the thorny aspects

2019 ◽  
Vol 10 (1) ◽  
pp. 56-67
Author(s):  
Tatiana-Camelia Dogaru Cruceanu
Keyword(s):  
Comparative Research ◽  
Comparative Method ◽  
Policy Research ◽  
Point Of View ◽  
Decision Makers ◽  
Theoretical Point ◽  
Policy Studies ◽  
New Approach ◽  
The Past ◽  
Policy Systems

Abstract Over the past decades, the comparative method has attracted the attention of the theorists, and studies based on this approach have increased in applied policy research. In their daily and strategically policy decisions, the decision makers from local, regional and national levels use more and more the comparative research methods, especially due to interlinked relationship and the need for bench learning and benchmarking practices. The comparative method allows the actors to analyse other experiences, and thus to take decisions more efficient. This is a normal, an inevitable situation, when the unit of analysis is a country, a field of matters or a process where researchers compare cases from empirical or theoretical point of view. The purpose of this paper is to provide a critical view on the capacity of comparative method to foster knowledge in policy studies. The intention is to see and to explore the utility of comparative method for policy studies and policy analysis, since a new approach “evidence-based policymaking” arise, emphasising the importance of using evidence from other political and policy systems.

scholarly journals The Invertebrate Antibody

2021 ◽  
pp. 1-2
Keyword(s):  
Receptor Gene ◽  
Genomic Data ◽  
Class Ii ◽  
Fc Receptor ◽  
Class I ◽  
Sea Star ◽  
Mhc Genes ◽  
The Past

Introduction Many researchers don’t believe in our works: they speak we are wrong when we evoke the Invertebrate Antibody...BUT: Discussion We have discovered, in the past, the sea star lymphocytes ( B and T sea star lymphocytes : cf Fig 1,2) : these cells of 4-5µ in diameter are smaller than Vertebrate lymphocytes And ...We discovered recently the IPA (Invertebrate Primitive Antibody) with the sea star IGKAPPA gene with IG sites (Meta Gene 2013). Therefore genomic data assert the evidence of primitive antibody in Echinodermata. Furthermore, we find MHC genes class I and class II in 2019 and Fab gene, Fc receptor gene in these Invertebrates

scholarly journals 44 GHz Methanol Maser Surveys

2012 ◽  
Vol 8 (S287) ◽  
pp. 133-140
Author(s):  
S. E. Kurtz
Keyword(s):  
Star Formation ◽  
Formation Process ◽  
Class Ii ◽  
Class I ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Methanol Maser ◽  
Star Forming Regions ◽  
Methanol Masers

AbstractClass I 44 GHz methanol masers are not as well-known, as common, or as bright as their more famous Class II cousins at 6.7 and 12.2 GHz. Nevertheless, the 44 GHz masers are commonly found in high-mass star forming regions. At times they appear to trace dynamically important phenomena; at other times they show no obvious link to the star formation process. Here, we summarize the major observational efforts to date, including both dedicated surveys and collateral observations. The principal results are presented, some that were expected, and others that were unexpected.

Ivan Petrović, Photographer, Archivist and Artist: Interview with Ivan Petrović

2017 ◽  
pp. 4-9
Author(s):  
Miha Colner ◽  
Ivan Petrović
Keyword(s):  
Point Of View ◽  
Artistic Expression ◽  
Film Production ◽  
Theoretical Point ◽  
Artistic Practice ◽  
Photographic Image ◽  
The Past ◽  
Archival Work

Ivan Petrović (1973) has been working in the fields of photography and art for twenty years as a researcher, creator and collector. Since 1997, he has been creating and publishing photographic projects that reflect the spirit of space and time in which they are created, while in his works he uses both documentary approaches as well as research principles. In 2011, together with photographer Mihail Vasiljević, he founded a para-institution, the Centre for Photography (CEF). Despite lacking its own premises, infrastructure or funds for performing its activities, the institution deals with the search, preservation, collection and analysis of local photographic materials from recent history. In the past ten years, Petrović also moved his artistic practice beyond mere artistic expression, since he addresses the phenomena of photography from an analytical-theoretical point of view. His interest lies in the nature of the photographic image and its role in society and historiography. In this spirit, long-term projects such as Documents (1997–2008), Images (2002–), Portfolio Belgrade (2015–) and the latest film production were created. The interview with Ivan Petrović took place on 1 September 2017 in Belgrade. The main themes were the role of photography in the dominant history, the boundary between one’s own practice and archival work, photography as an art and the likes. Keywords: collection, documentary, photography's role, preservation, research

Characteristics and Evaluation of Zao IV Group of Kong I Zone in Zaobei Oilfield

2013 ◽  
Vol 295-298 ◽  
pp. 3281-3284
Author(s):  
Ying Hua Yu ◽  
Dan Dan Yuan ◽  
Xiao Yu Yang
Keyword(s):  
Physical Properties ◽  
Comprehensive Evaluation ◽  
Sedimentary Facies ◽  
Class Ii ◽  
Class I ◽  
Class Iii ◽  
Quality Difference ◽  
Relative Quality

Based on the characteristics of sedimentary facies, lithology, physical properties and heterogeneity for the reservoirs, a comprehensive evaluation for the reservoirs is researched, so as to determine the relative quality difference for different layers and different blocks, providing geological pursuant to the development of oilfield. The results show that Zao IV Group of Kong I Zone can be divided into three types, of which class I accounted for 26%, class II accounted for 42% and class III accounted for 32%, and reflected the strong degree of inhomogeneous of reservoir.

scholarly journals Root layering in a tropical forest after logging (Central Vietnam)

2012 ◽  
Vol 60 (1) ◽  
pp. 23-28
Author(s):  
Zdeněk Čermák
Keyword(s):  
Root System ◽  
Root Systems ◽  
Class Ii ◽  
Total Weight ◽  
Class I ◽  
Class Iii ◽  
Tropical Rain Forests ◽  
Harvest Intensity ◽  
The Past ◽  
Central Vietnam

Indigenous stands of tropical rain forests in the region of Kon Ha Nung are one of the most preserved forests in the whole Vietnam. Despite the logging activities mainly in the 1970’s, it was possible to preserve intact forests free from any primary harvesting. In the past, other stands were influenced by the logging to various extent. Some of those stands are managed presently; others were left to natural development. This paper deals with the influence of harvesting activities on the root system in forest stands. In primary stands and in stands with known harvest intensity, samples of root systems were collected. The total weight of dry basis and mainly their layering within the soil profile were assessed. The collected roots were divided into three classes: class I – ≤ 1.0 mm, class II 1.1–5.0 mm, class III – over 5.0 mm in the diameter. In the monitored plots, the total weight of dry basis of fine roots to 1.0 mm ranged from 2.34–3.24 t∙ha−1. The weight of dry basis of roots from 1.0–5.0 mm ranged from 6.57–9.69 t∙ha−1. The majority of roots of class I is presented in the top 10.0 cm of the soil and their share drops with the increasing depth. The roots of class II are distributed more equally. It was impossible to prove the influence of the logging on the root system.

A Comparative Study of Un-Modified and Modified Acrylate-SiO2 Nanocomposites

MRS Advances ◽  
2017 ◽  
Vol 2 (49) ◽  
pp. 2737-2743
Author(s):  
Mireya L. Hernández-Vargas ◽  
Rubén Castillo-Perez ◽  
Oscar Hernández-Guerrero ◽  
Bernardo F. Campillo-Illanes ◽  
Osvaldo Flores-Cedillo
Keyword(s):  
Physical Properties ◽  
Van Der Waals ◽  
Chemical Properties ◽  
Class Ii ◽  
Decomposition Temperature ◽  
Van Der Waals Interactions ◽  
Class I ◽  
Covalent Bonds ◽  
Neat Polymer ◽  
Hybrid Compounds

ABSTRACTBased on the nature of the links and interactions existing at the hybrid interface, hybrid materials can be broadly classified in two main designations: a) Hybrid compounds Class I, that include all systems with electrostatic forces, hydrogen bonding or Van der Waals interactions and b) Hybrid compounds Class II, showing that the inorganic and organic components are linked through strong covalent or ionic-covalent bonds. The physico–chemical properties of nanostructured copolymer acrylates based on butyl acrylate (BA), methyl methacrylate (MMA) and acrylic acid (AA) has been investigated employing un-modified SiO2 (Class I) and modified SiO2 particles (Class II) using 3-(trimethoxysilyl) propyl methacrylate (MPS) as compatibilizing agent. The synthesis was carried out using seeded batch emulsion polymerization system. Metastable nanostructured emulsions containing 1 wt% nanoparticles were obtained. Films casted from the in-situ nanostructured latex exhibited excellent optical transparency suggesting good nanoparticles dispersion. However, the mechanical properties showed by SiO2-MPS nanocomposite, are better than the Class I hybrid compounds. Therefore, SiO2-MPS surface treatment prior to polymerization enhances the physical properties of copolymer BA-MMA-AA film. The mass loss derivative traces for the polyacrylic nanocomposites and the neat polymer obtained by thermogravimetric analysis showed that the onset temperature for thermal decomposition was shifted towards a higher temperature than the neat polyacrylic, indicating the enhancement of thermal stability of the un-modified SiO2 nanocomposite. However, there is a decrease of 40°C in the decomposition temperature for the modified polyacrylic nanocomposite. The results obtained so far have shown that weak Van der Waals and H-bonding interactions may be sufficient to enable improvement of the physical properties of the acrylate nanocomposites.

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