ABSTRACT
A growing body of evidence exists to support a detrimental effect of the presence of artificial light at night (ALAN) on life-history and fitness traits. However, few studies simultaneously investigate multiple traits and the life stages at which changes manifest. We experimentally manipulated ALAN intensities, within those found in the natural environment, to explore the consequences for growth, survival, and reproductive success of the field cricket, Teleogryllus commodus. We reared crickets from egg to adult under a daily light-cycle consisting of 12 hr bright daylight (2,600 lx) followed by either 12 hr darkness (0 lx) or dim-light environments (1, 10, or 100 lx). We found egg hatch, adult survival, and reproductive measures were largely comparable for all treatments. However, juvenile development time (number of days from egg to adult) was on average 10 days (14%) longer and adults were also larger when crickets were exposed to any light at night (1, 10, or 100 lx). Our data demonstrate that chronic lifetime exposure to ALAN can modulate the timing of life-history events and may disrupt phenology to a similar extent as other abiotic factors.
Subject(s)
Gryllidae/radiation effects , Light , Animals , Body Size , Female , Fertility/radiation effects , Gryllidae/growth & development , Gryllidae/physiology , Lighting , Longevity/radiation effects , MaleABSTRACT
The genus Mycobacterium consists of over 120 known species, some of which (e.g. M. bovis and M. tuberculosis) contribute extensively to the burden of infectious disease in humans and animals, whilst others are commonly found in the environment but may rarely if ever be disease-causing. This paper reviews the mycobacteria found in southern Africa, focussing on those in the M. tuberculosis complex as well as the non-tuberculous mycobacteria (NTM), identifying those found in the area and including those causing disease in humans and animals, and outlines some recent reports describing the distribution and prevalence of the disease in Africa. Difficulties in diagnosis, host preference and reaction, immunology and transmission are discussed.
Subject(s)
Animals, Wild/microbiology , Mycobacterium Infections/microbiology , Mycobacterium Infections/veterinary , Mycobacterium/classification , Africa, Southern , Animals , Humans , Mycobacterium/isolation & purification , Mycobacterium Infections/diagnosis , PhylogenyABSTRACT
A Ho:YLF laser pumped HBr molecular laser was developed that produced up to 2.5 mJ of energy in the 4 micron wavelength region. The Ho:YLF laser was fiber pumped using a commercial Tm:fibre laser. The Ho:YLF laser was operated in a single longitudinal mode via injection seeding with a narrow band diode laser which in turn was locked to one of the HBr transitions. The behavior of the HBr laser was described using a rate equation mathematical model and this was solved numerically. Good agreement both qualitatively and quantitatively between the model and experimental results was obtained.
Subject(s)
Lasers , Computer-Aided Design , Equipment Design , Equipment Failure Analysis , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
A numerical model of a three-mirror resonator for a TE CO(2) laser was developed. This model was used to determine if a three-mirror resonator with an etalon could be used to ensure tunable single-mode action on the lower gain lines of CO(2). Single-mode pulse energies were also predicted and good agreement was found with experimentally measured values. An analysis of the thermal frequency drift of the resonator is also presented.
