scholarly journals Celebrating 30 years of science from the James Clerk Maxwell Telescope

2017 ◽  
Vol 4 (9) ◽  
pp. 170754
Author(s):  
Ian Robson ◽  
Wayne S. Holland ◽  
Per Friberg

The James Clerk Maxwell Telescope (JCMT) has been the world’s most successful single-dish telescope at submillimetre wavelengths since it began operations in 1987. From the pioneering days of single-element photometers and mixers, through to the state-of-the-art imaging and spectroscopic cameras, the JCMT has been associated with a number of major scientific discoveries. Famous for the discovery of ‘SCUBA’ galaxies, which are responsible for a large fraction of the far-infrared background, the JCMT has pushed the sensitivity limits arguably more than any other facility in this most difficult of wavebands in which to observe. Closer to home, the first images of huge discs of cool debris around nearby stars gave us clues to the evolution of planetary systems, further evidence of the importance of studying astrophysics in the submillimetre region. Now approaching the 30th anniversary of the first observations, the telescope continues to carry out unique and innovative science. In this review article, we look back on some of the major scientific highlights from the past 30 years.

2003 ◽  
Vol 13 (02) ◽  
pp. 601-676 ◽  
Author(s):  
S. P. Mickan ◽  
X.-C. Zhang

Terahertz (THz) radiation occupies part of the electromagnetic spectrum between the infrared and microwave bands. Until recently, technology at THz frequencies was under-developed compared to the rest of the electromagnetic spectrum, leaving a gap between millimeter waves and the far-infrared (FIR). In the past decade, interest in the THz gap has been increased by the development of ultrafast laser-based T-ray systems and their demonstration of diffraction-limited spatial resolution, picosecond temporal resolution, DC-THz spectral bandwidth and signal-to-noise ratios above 104. This chapter reviews the development, the state of the art and the applications of T-ray spectrometers. Continuous-wave (CW) THz-frequency sources and detectors are briefly introduced in comparison to ultrafast pulsed THz systems. An emphasis is placed on experimental applications of T-rays to sensing and imaging, with a view to the continuing advance of technologies and applications in the THz band.


2020 ◽  
Vol 10 ◽  
pp. 17-24
Author(s):  
Saeed N. Asiri ◽  
Larry P. Tadlock ◽  
Emet Schneiderman ◽  
Peter H. Buschang

Over the past two decades, artificial intelligence (AI) and machine learning (ML) have undergone considerable development. There have been various applications in medicine and dentistry. Their application in orthodontics has progressed slowly, despite promising results. The available literature pertaining to the orthodontic applications of AI and ML has not been adequately synthesized and reviewed. This review article provides orthodontists with an overview of AI and ML, along with their applications. It describes state-of-the-art applications in the areas of orthodontic diagnosis, treatment planning, growth evaluations, and in the prediction of treatment outcomes. AI and ML are powerful tools that can be utilized to overcome some of the clinical problems that orthodontists face daily. With the availability of more data, better AI and ML systems should be expected to be developed that will help orthodontists practice more efficiently and improve the quality of care.


1990 ◽  
Vol 139 ◽  
pp. 149-155
Author(s):  
Martin Harwit

Diffuse infrared background radiation measurements have traditionally been carried out across broad wavelength bands, primarily because there seldom appeared to be sufficient energy available in individual spectral lines to make such observations possible. In the past few years, far-infrared searches for spectral line background radiation have become possible, and considerably greater use of these capabilities will become available in the next few years. The promise of this kind of observation is reviewed.


Author(s):  
Carl E. Henderson

Over the past few years it has become apparent in our multi-user facility that the computer system and software supplied in 1985 with our CAMECA CAMEBAX-MICRO electron microprobe analyzer has the greatest potential for improvement and updating of any component of the instrument. While the standard CAMECA software running on a DEC PDP-11/23+ computer under the RSX-11M operating system can perform almost any task required of the instrument, the commands are not always intuitive and can be difficult to remember for the casual user (of which our laboratory has many). Given the widespread and growing use of other microcomputers (such as PC’s and Macintoshes) by users of the microprobe, the PDP has become the “oddball” and has also fallen behind the state-of-the-art in terms of processing speed and disk storage capabilities. Upgrade paths within products available from DEC are considered to be too expensive for the benefits received. After using a Macintosh for other tasks in the laboratory, such as instrument use and billing records, word processing, and graphics display, its unique and “friendly” user interface suggested an easier-to-use system for computer control of the electron microprobe automation. Specifically a Macintosh IIx was chosen for its capacity for third-party add-on cards used in instrument control.


Author(s):  
Eleanor Heisey

Johannes Brahms’s deep engagement with the past contributed to his compositional style in many ways. This article considers Brahms techniques that look back to and expand on those of Renaissance composers, in particular metric conflict and cadences, voice displacement, changes in proportion, rhythmic augmentation and diminution, and the hocket. Examples are taken from Brahms’s Academic Festival Overture, Variations On A Theme By Haydn, Piano Quartet in A Major, and Symphony No. 3 in F Major.


1963 ◽  
Vol 3 (3) ◽  
pp. 424-442
Author(s):  
Jamila Akhtar

This review of the Literacy and Education Bklletin1 of the 1961 Census is fourth in the series of review articles published in this journal2. The Bulletin under review forms a part of the interim report on the characteristics of the population of Pakistan. It gives information on the number of illiterate and literate persons by age and sex for rural and urban areas on division and district basis; illiterate and literate.population in selected cities and towns; and the educational levels attained by the literate population by age and sex for divisions and districts. Relevant statistical notes and statements precede the tables in the Bulletin. The objective of this review is to describe the meaningfulness and significance of literacy statistics. To this end, a distinction is made between formal and functional levels of literacy. Comparisons of the 1951 and 1961 census figures are undertaken to indicate the progress of literacy and education during the past decade with reference to the effect of intercensal rate of population growth on such progress. Certain questions regarding the reliability of data are raised, which emphasize the need for caution in the interpretation of literacy statistics.


2020 ◽  
Vol 24 (24) ◽  
pp. 2823-2844
Author(s):  
Aditya Bhattacharyya

: Multiheteroatom-containing small-sized cyclic molecules such as 2- iminothiazolidines are often found to possess beneficial pharmacological properties. In this review article, the biological significance of 2-iminothiazolidines is discussed and the literature reports published in the last 15 years spanning from 2006 to 2020 describing various preparative routes to access 2-iminothiazolidine derivatives have been categorically and chronologically described. The notable synthetic methods discussed here involve ringexpansion transformations of nonactivated and activated aziridines, thiiranes, epoxides, and other miscellaneous reactions.


Author(s):  
Mohamed Ibrahim Elzagheid

: Nucleosides and their analogues have been in use for many years and have become essential for treating patients with viral infections. Many additional nucleoside drugs have been approved over the past decades. This strongly demonstrates how important these compounds are and the crucial role they play. Given that a significant amount of research and literature has been documented regarding nucleoside analogues, this review article mainly focuses the discussion on nucleosides and nucleoside analogous that have proven to play significant role or be emerging in the treatment of known viral infections. This covers the names, structures, applications, toxicity, and mode of action of relevant nucleoside analogues.


Author(s):  
Ayesha Jalil ◽  
Yaxin O Yang ◽  
Zhendong Chen ◽  
Rongxuan Jia ◽  
Tianhao Bi ◽  
...  

: Hypervalent iodine reagents are a class of non-metallic oxidants have been widely used in the construction of several sorts of bond formations. This surging interest in hypervalent iodine reagents is essentially due to their very useful oxidizing properties, combined with their benign environmental character and commercial availability from the past few decades ago. Furthermore, these hypervalent iodine reagents have been used in the construction of many significant building blocks and privileged scaffolds of bioactive natural products. The purpose of writing this review article is to explore all the transformations in which carbon-oxygen bond formation occurred by using hypervalent iodine reagents under metal-free conditions


Author(s):  
Xabier Rodríguez-Martínez ◽  
Enrique Pascual-San-José ◽  
Mariano Campoy-Quiles

This review article presents the state-of-the-art in high-throughput computational and experimental screening routines with application in organic solar cells, including materials discovery, device optimization and machine-learning algorithms.


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