The Cyrenaican Prehistory Project 2011: Late-Holocene environments and human activity from a cave fill in Cyrenaica, Libya

Little is known about late Holocene environmental change in Cyrenaica. The late Holocene sequence in the Haua Fteah, the key regional site, is highly discontinuous and characterised by stable-burning deposits. The geoarchaeology of the late-Holocene cave fill of a small cave, CP1565, located close to the Haua Fteah, is described. The well-stratified sequence, dating from the fourth century AD to the present day, provides a glimpse of life at the bottom of the settlement hierarchy and of changing environments over the last 1600 years, with degraded vegetation and aridity in the ‘Little Ice Age’.

Lighting conditions and optical filters effects on visual performance of speleologists exposed to cave environments

The aim of this study is to evaluate lighting conditions and speleologists’ visual performance using optical filters when exposed to the lighting conditions of cave environments. A crosssectional study was conducted. Twenty-three speleologists were submitted to an evaluation of visual function in a clinical lab. An examination of visual acuity, contrast sensitivity, stereoacuity and flashlight illuminance levels was also performed in 16 of the 23 speleologists at two caves deprived of natural lightning. Two organic filters (450 nm and 550 nm) were used to compare visual function with and without filters. The mean age of the speleologists was 40.65 (± 10.93) years. We detected 26.1% participants with visual impairment of which refractive error (17.4%) was the major cause. In the cave environment the majority of the speleologists used a head flashlight with a mean illuminance of 451.0 ± 305.7 lux. Binocular visual acuity (BVA) was -0.05 ± 0.15 LogMAR (20/18). BVA for distance without filter was not statistically different from BVA with 550 nm or 450 nm filters (p = 0.093). Significant improved contrast sensitivity was observed with 450 nm filters for 6 cpd (p = 0.034) and 18 cpd (p = 0.026) spatial frequencies. There were no signs and symptoms of visual pathologies related to cave exposure. Illuminance levels were adequate to the majority of the activities performed. The enhancement in contrast sensitivity with filters could potentially improve tasks related with the activities performed in the cave.

Niagara Guide looking into Cave of the Winds - Niagara Falls, U.S.A.

The description reads "(10) An old Niagara Guide - looking into the awe-inspiring Cave of the Winds - Niagara Falls, U.S.A.".

Cave of the Winds on the American Side Poster

Cave of the Winds on the American Side. This poster contains a poem by Mary S. Pond called Cave of the Winds, 35 cm. x 19 cm. The guides are listed as F.H. Johnson and Son. There is a portion of the poster missing from the upper left hand corner. This does affect the text. This newsprint article is mounted in a cardboard frame, 1860.

Cave of the Winds, Goat Island, U.S.A.

Cave of the Winds, Goat Island, U.S.A. This is touted as the only place on the globe where rainbows form an entire circle. Geo. W. Wright is listed as the lessee. 30 cm. x 14 cm. newsprint. There is a slight wearing away of the edges. This does not affect text, n.d.

Entrant amb curiositat a la gran obra de l'artista Nick Cave

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