Solar Ultraviolet on Tropical Mountains: Can It Affect Plant Speciation?

1980 ◽  
Vol 115 (6) ◽  
pp. 880-883 ◽  
Author(s):  
David W. Lee ◽  
J. Brian Lowry
Keyword(s):  
Tropical Mountains ◽  
Solar Ultraviolet

Simplified Calibration for Broadband Solar Ultraviolet Radiation Measurements¶

2003 ◽  
Vol 78 (6) ◽  
pp. 603 ◽  
Author(s):  
A. Oppenrieder ◽  
P. Hoeppe ◽  
P. Koepke ◽  
J. Reuder ◽  
J. Schween ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Solar Ultraviolet Radiation ◽  
Solar Ultraviolet ◽  
Radiation Measurements

DUELING EROSION FRONTS: GLACIAL BUZZCUTTING AND NONGLACIAL SCARP ENCROACHMENT LIMIT THE HEIGHT OF TROPICAL MOUNTAINS

2016 ◽  
Author(s):  
Maxwell Cunningham ◽  
◽  
Colin Stark ◽  
Michael R. Kaplan ◽  
Joerg M. Schaefer
Keyword(s):  
Tropical Mountains

Community characteristics of forest understory birds along an elevational gradient in the Horn of Africa: A multi-year baseline

The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Survival Rates ◽  
Elevational Gradient ◽  
Forest Understory ◽  
Bird Abundance ◽  
Tropical Mountains ◽  
Demographic Rates ◽  
Understory Birds ◽  
Over Time

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.

scholarly journals Impact of Weed Control by Hand Tools on Soil Erosion under a No-Tillage System Cultivation

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 974
Author(s):  
Rafael Blanco-Sepúlveda ◽  
Amilcar Aguilar-Carrillo ◽  
Francisco Lima
Keyword(s):  
Soil Erosion ◽  
Weed Control ◽  
Soil Cover ◽  
Soil Surface ◽  
Conservation Agriculture ◽  
Soil Disturbance ◽  
No Tillage ◽  
Tropical Mountains ◽  
Litter Cover ◽  
Vegetal Cover

In conservation agriculture, the no-tillage cultivation system and the retention of permanent vegetal cover are crucial to the control of soil erosion by water. This paper analyses the cultivation of maize under no-tillage, with particular reference to the effect produced on soil erosion when weed control is performed by a hand tool (machete), which disturbs the surface of the soil, and to the behavior of the soil cover in these circumstances. The study area is located in the humid tropical mountains of northern Nicaragua (Peñas Blancas Massif Nature Reserve). The results obtained show that 59.2% of the soil surface was affected by appreciable levels of sheet and splash erosion, although the vegetal cover of the soil was relatively high (with average weed and litter cover of 33.9% and 33.8%, respectively). The use of machetes for weed control provoked considerable soil disturbance, which explained the high rates of erosion observed. Moreover, this form of soil management disturbs the litter layer, making it less effective in preventing erosion. The litter remains loose on the soil surface, and so an increase in soil cover does not achieve a proportionate reduction in the area affected by erosion; thus, even with 80–100% weed and litter cover, 42% of the cultivated area continued to present soil erosion.

scholarly journals The Anti-Ageing and Whitening Potential of a Cosmetic Serum Containing 3-O-ethyl-l-ascorbic Acid

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 406
Author(s):  
Nicola Zerbinati ◽  
Sabrina Sommatis ◽  
Cristina Maccario ◽  
Serena Di Francesco ◽  
Maria Chiara Capillo ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Dermal Fibroblasts ◽  
Melanin Content ◽  
Dna Protection ◽  
Melanin Pigmentation ◽  
Intrinsic Factors ◽  
Reconstructed Human Epidermis ◽  
Solar Ultraviolet ◽  
Damage Marker ◽  
Extrinsic And Intrinsic Factors

Skin ageing has many manifestations such as wrinkles, dryness, hyperpigmentation, and uneven skin tone. Extrinsic and intrinsic factors, especially solar ultraviolet light (UVB), contribute to skin ageing; its main features are brown spots, alterations in melanin pigmentation, and a decrease in collagen and hyaluronic acid linked to oxidative stress. Several studies showed that topical products containing ingredients with antioxidant activity can reduce oxidative damage; to provide a maximum anti-ageing effect to the skin, topical products can combine various ingredients. C-SHOT SERUM contains a combination of two molecules with a proven anti-ageing activity: a high percentage (30%) of a more stable vitamin C derivative, 3-O-ethyl-l-ascorbic acid, and lactic acid (1%). The product showed a high biocompatibility, assessed through an MTT assay on keratinocytes and on Reconstructed Human Epidermis (RHE, SkinEthic); the anti-ageing activity was demonstrated on human dermal fibroblasts and keratinocytes by a statistically significant increase in collagen production and a reduction of a UVB-induced DNA damage marker (γ-H2AX histone), indicating DNA protection. Moreover, a depigmenting activity, shown by a highly significant decrease in melanin content on treated Reconstructed Human Pigmented Epidermis (RHPE), was assessed. According to the data of our study, the tested product contrasts the effect of skin ageing and irregular pigmentation due to the physiological decline of the skin.

scholarly journals The Early Days of Personal Solar Ultraviolet Dosimetry

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 125 ◽  
Author(s):  
Brian Diffey
Keyword(s):  
Uv Radiation ◽  
Human Exposure ◽  
Ground Level ◽  
Uv Exposure ◽  
Population Exposure ◽  
Atmospheric Ozone ◽  
Quantitative Understanding ◽  
Solar Uv ◽  
The Impact ◽  
Solar Ultraviolet

In the early 1970s, environmental conservationists were becoming concerned that a reduction in the thickness of the atmospheric ozone layer would lead to increased levels of ultraviolet (UV) radiation at ground level, resulting in higher population exposure to UV and subsequent harm, especially a rise in skin cancer. At the time, no measurements had been reported on the normal levels of solar UV radiation which populations received in their usual environment, so this lack of data, coupled with increasing concerns about the impact to human health, led to the development of simple devices that monitored personal UV exposure. The first and most widely used UV dosimeter was the polymer film, polysulphone, and this review describes its properties and some of the pioneering studies using the dosimeter that led to a quantitative understanding of human exposure to sunlight in a variety of behavioral, occupational, and geographical settings.

Solar ultraviolet irradiance observed from southern Argentina: September 1990 to March 1991

1993 ◽  
Vol 98 (D5) ◽  
pp. 8891-8897 ◽  
Author(s):  
J. E. Frederick ◽  
P. F. Soulen ◽  
S. B. Diaz ◽  
I. Smolskaia ◽  
C. R. Booth ◽  
...  
Keyword(s):  
Ultraviolet Irradiance ◽  
Solar Ultraviolet
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