نتایج جستجو برای: limestone caves

تعداد نتایج: 8186  

2010
Suresh K Nath Robin K Dutta

An examination of defluoridation by industrial grade limestone indicated that a combination of precipitation and adsorption of fluoride can be more effective for defluoridation of water. Pre-acidified fluoride water using two edible acids, viz., acetic acid (AA) and citric acid (CA) have been used for treatment by crushed limestone of diameter 3-4 mm to precipitate fluoride as CaF2 in addition ...

2017
Andrew R. Farrant Tony Harrison

The UK has a wide variety of hypogenic caves, including transverse maze caves, relict hydrothermal caves, gypsum mazes and hypogenic karst associated with water rising up deep thrust faults. While few of these are particularly extensive, they offer insights into the mechanisms of speleogenesis and mineralisation. The best developed hypogenic caves in the UK are in the Carboniferous limestones o...

Journal: :Geomicrobiology journal 2014
Jennifer J Marshall Hathaway Robert L Sinsabaugh Maria De Lurdes N E Dapkevicius Diana E Northup

Lava caves are an understudied ecosystem in the subterranean world, particularly in regard to nitrogen cycling. The diversity of ammonia oxidation (amoA) and nitrogen fixation (nifH) genes in bacterial mats collected from lava cave walls on the island of Terceira (Azores, Portugal) was investigated using denaturing gradient gel electrophoresis (DGGE). A total of 55 samples were collected from 1...

Journal: :Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology] 2018
Muhammad Yasir

In this study for the first-time microbial communities in the caves located in the mountain range of Hindu Kush were evaluated. The samples were analyzed using culture-independent (16S rRNA gene amplicon sequencing) and culture-dependent methods. The amplicon sequencing results revealed a broad taxonomic diversity, including 21 phyla and 20 candidate phyla. Proteobacteria were dominant in both ...

Journal: :Science 1887

Journal: :Science 1905

2011
Pekka Vilkamaa Heikki Hippa Steven J. Taylor

Camptochaeta prolixasp. n. (Diptera, Sciaridae) is described from caves in Nevada, and three other congeneric species are recorded from caves in Nevada and Arkansas, United States. The new species shows some indication to a subterranean mode of life, including long antenna and legs, and in some specimens, reduction of the eye bridge.

Journal: :AJNR. American journal of neuroradiology 1995
M J Ruocco H A Robles K C Rao R A Armonda S L Ondra

An unusual case of bilateral intratentorial lipomas with extension into Meckel's caves and the cerebellopontine angle is described. Surgical and histopathologic correlation demonstrate that the lipoma encased the trigeminal nerve in Meckel's caves. The origin of the lipoma from the anteromedial margins of the tentorium is discussed and correlated with a recently proposed theory for the developm...

2008
G. M. Levkovskaya

Caves and rockshelters are found all over the world, and they have been frequently occupied throughout prehistory and early history. In many areas of Europe, some of these natural places are still used as sites of worship and as shelter against the elements. There is great variability in their use. Some appear to only have traces of short occupations, while others have thick cultural deposits, ...

2018
Rodolfo Jaffé Xavier Prous Allan Calux Markus Gastauer Gilberto Nicacio Robson Zampaulo Pedro W.M. Souza-Filho Guilherme Oliveira Iuri V. Brandi José O. Siqueira

The degradation of subterranean habitats is believed to represent a serious threat for the conservation of obligate subterranean dwellers (troglobites), many of which are short-range endemics. However, while the factors influencing cave biodiversity remain largely unknown, the influence of the surrounding landscape and patterns of subterranean connectivity of terrestrial troglobitic communities...

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