Search results for "Glare"
showing 10 items of 103 documents
High-elevational occurrence of two tick species, Ixodes ricinus and I. trianguliceps, at their northern distribution range
2021
Abstract Background During the last decades a northward and upward range shift has been observed among many organisms across different taxa. In the northern hemisphere, ticks have been observed to have increased their latitudinal and altitudinal range limit. However, the elevational expansion at its northern distribution range remains largely unstudied. In this study we investigated the altitudinal distribution of the exophilic Ixodes ricinus and endophilic I. trianguliceps on two mountain slopes in Norway by assessing larval infestation rates on bank voles (Myodes glareolus). Methods During 2017 and 2018, 1325 bank voles were captured during the spring, summer and autumn at ten trapping st…
Balancing selection maintains polymorphisms at neurogenetic loci in field experiments
2017
Most variation in behavior has a genetic basis, but the processes determining the level of diversity at behavioral loci are largely unknown for natural populations. Expression of arginine vasopressin receptor 1a (Avpr1a) and oxytocin receptor (Oxtr) in specific regions of the brain regulates diverse social and reproductive behaviors in mammals, including humans. That these genes have important fitness consequences and that natural populations contain extensive diversity at these loci implies the action of balancing selection. In Myodes glareolus, Avpr1a and Oxtr each contain a polymorphic microsatellite locus located in their 5′ regulatory region (the regulatory region-associated microsatel…
Fitness costs of increased cataract frequency and cumulative radiation dose in natural mammalian populations from Chernobyl
2015
AbstractA cataract is a clouding of the lens that reduces light transmission to the retina and it decreases the visual acuity of the bearer. The prevalence of cataracts in natural populations of mammals and their potential ecological significance, is poorly known. Cataracts have been reported to arise from high levels of oxidative stress and a major cause of oxidative stress is ionizing radiation. We investigated whether elevated frequencies of cataracts are found in eyes of bank voles Myodes glareolus collected from natural populations in areas with varying levels of background radiation in Chernobyl. We found high frequencies of cataracts in voles collected from different areas in Chernob…
Sex and age-specific differences in ultraviolet reflectance of scent marks of bank voles ( Clethrionomys glareolus )
2000
Scent markings of voles are visible via their ultraviolet reflection. Kestrels, and possibly other diurnal raptors, may use this property when hunting. We performed a laboratory study on bank voles to determine whether UV-reflectance of scent marks differs in relation to sex, age and social status. When reflectance spectra of scent marks were measured with a spectro-radiometer, we found UV reflectance to be strongest in mature males. There were no differences between mature females and immature juveniles, nor between sexes in juveniles or mature and immature individuals in females. Moreover, we did not find any difference in UV reflectance between dominant and subordinate mature males. The …
Increased radiation from Chernobyl decreases the expression of red colouration in natural populations of bank voles (Myodes glareolus)
2014
AbstractPheomelanin is a pink to red version of melanin pigment deposited in skin and hair. Due to its bright colour, pheomelanin plays a crucial function in signalling, in particular sexual signalling. However, production of pheomelanin, as opposed to its dark alternative, eumelanin, bears costs in terms of consumption of antioxidants important for protection of DNA against naturally produced reactive oxidative species. Therefore, decreased expression of pheomelanin is expected in organisms exposed to severe oxidative stress such as that caused by exposure to chronic ionizing radiation. We tested if variable exposure to radiation among natural populations of bank voles Myodes glareolus in …
Long-term fitness benefits of polyandry in a small mammal, the bank vole Clethrionomys glareolus.
2008
Polyandry, i.e. mating with multiple males within one reproductive event, is a common female mating strategy but its adaptive function is often unclear. We tested whether polyandrous females gain genetic benefits by comparing fitness traits of monandrous (mated twice with a single male) and polyandrous (mated twice with two different males) female bank volesClethrionomys glareolus. We raised the offspring in the laboratory until adulthood and measured their body size, before releasing them to outdoor enclosures to overwinter. At the onset of the breeding season in the following spring, we found that offspring of polyandrous females performed significantly better at reproduction than those o…
The effect of chronic low-dose environmental radiation on organ mass of bank voles in the Chernobyl Exclusion Zone
2020
Purpose: Animals are exposed to environmental ionizing radiation (IR) externally through proximity to contaminated soil and internally through ingestion and inhalation of radionuclides. Internal organs can respond to radioactive contamination through physiological stress. Chronic stress can compromise the size of physiologically active organs, but studies on wild mammal populations are scarce. The effects of environmental IR contamination on organ masses was studied by using a wild rodent inhabiting the Chernobyl Exclusion Zone (CEZ). Material and Methods: The masses of brain, heart, kidney, spleen, liver and lung were assessed from bank voles (Myodes glareolus) captured from areas across r…
Visual function comparison of 2 aspheric multifocal intraocular lenses
2011
To compare visual function after bilateral implantation of the multifocal Lentis Mplus LS-312 with a nonrotational symmetrical design (copolymer aspheric) or the Acrysof Restor SN6AD1 +3.0 D (hybrid aspheric) intraocular lens (IOL).Fernández-Vega Ophthalmological Institute, Oviedo, Spain.Comparative case series.Six months postoperatively, corrected distance visual acuity (CDVA), distance-corrected near visual acuity (DCNVA), the defocus curve, and photopic and mesopic contrast sensitivity with and without glare were measured.The mean CDVA was 0.02 ± 0.06 (SD) with the copolymer aspheric IOL and -0.06 ± 0.05 logMAR with the hybrid aspheric IOL (P=.07) and the mean DCNVA, 0.10 ± 0.06 and -0.0…
Visual Performance of a Multifocal Toric Soft Contact Lens
2012
PURPOSE To evaluate the visual performance of the Proclear multifocal toric contact lens (CL; CooperVision, US) for both presbyopia and astigmatism correction. METHODS In this crossover study design, 20 presbyopic subjects with astigmatism were fitted in a random order with either Proclear multifocal toric CL or Proclear toric single vision distance CL (DCL) combined with reading spectacles. After 1 month, high-contrast distance visual acuity, near high-contrast visual acuity, distance contrast sensitivity (CS) under photopic and mesopic conditions without and with glare, near CS, defocus curve, and stereopsis were measured. Subjects were then refitted with the alternative correction, and t…
Visual function after implantation of an aspheric bifocal intraocular lens.
2009
Purpose To evaluate distance, intermediate, and near vision after bifocal aspheric AcrySof ReSTOR SN6AD1 intraocular lens (IOL) implantation. Setting Fernandez-Vega Ophthalmological Institute, Oviedo, Spain. Methods Binocular distance best corrected visual acuity (BCVA) (4.0 m), best distance-corrected near (40.0 cm) and intermediate (70.0, 60.0, 50.0 cm) acuities, and contrast sensitivity under photopic (85.0 candelas [cd]/m 2 ) and mesopic (3.0 cd/m 2 ) conditions with and without glare were measured postoperatively. A patient-satisfaction and visual phenomena questionnaire was administered. Results Six months postoperatively, the mean acuities (logMAR) were binocular BCVA, −0.064 ± 0.049…