Rodriguésia ◽  
2012 ◽  
Vol 63 (1) ◽  
pp. 101-128 ◽  
Author(s):  
Piero Giuseppe Delprete ◽  
Jomar Gomes Jardim

The Rubiaceae is the fourth Angiosperm family in number of species in the World and in the Neotropics. Its overwhelming diversity and presence in most biomes, and at most vegetation layers, makes this family one of the most important components of tropical vegetation. During the last two decades, family classification went through several reorganizations, mostly influenced by the advent of molecular phylogenetic studies, and many taxonomic revisions and floristic studies on Brazilian Rubiaceae have become available. In view of the considerable amount of literature that has recently been produced on Neotropical Rubiaceae, the present work has two main objectives: the first is to offer an overall view of the most recent family classification with emphasis on the genera of Rubiaceae occurring in Brazil, and to indicate particular taxa that are still in need of phylogenetic and taxonomic studies; the second objective is to present a short discussion on the state of floristic and taxonomic knowledge with respect to the various regions of Brazil, indicating the taxa and the geographic areas that need to be studied.


2020 ◽  
Vol 8 ◽  
pp. 39-52
Author(s):  
Kumar Khatri ◽  
Bibhuti Ranjan Jha ◽  
Smriti Gurung ◽  
Udhab Raj Khadka

This review describes the current status of freshwater fish diversity, their IUCN categories and threats to fish fauna in Nepal. The freshwater systems of the country are known to harbor over 220 fish species, thereby indicating a rich ichthyofaunal diversity. However, this number varies from author to author. Cyprinidae is the most common and dominant taxon. A total of 15 endemic and 15 exotic fish species have been reported. A total of 34 fish species have been listed under the IUCN Red List threatened categories. Major threats to fish include damming and pollution. Fish diversity studies have mainly focused on inventories only. Studies focusing on river longitudinal aspects, the inclusion of spatio-temporal aspects, and rigorous taxonomic studies combined with genetic studies are crucial to develop strategic conservation measures of fish fauna in Nepal.


1966 ◽  
Vol 25 ◽  
pp. 266-267
Author(s):  
R. L. Duncombe

An examination of some specialized lunar and planetary ephemerides has revealed inconsistencies in the adopted planetary masses, the presence of non-gravitational terms, and some outright numerical errors. They should be considered of temporary usefulness only, subject to subsequent amendment as required for the interpretation of observational data.


Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.


2021 ◽  
Author(s):  
Yuanhong Ma ◽  
Shao-Jie Lou ◽  
Zhaomin Hou

This review article provides a comprehensive overview to recognise the current status of electron-deficient boron-based catalysis in C–H functionalisations.


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