A COMPARISON OF THE EFFECTIVENESS OF THE “TOOTHKEEPER’ AND A TRADITIONAL DENTAL HEALTH EDUCATION PROGRAM

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66303/1/j.1752-7325.1975.tb04031.x.pd

Ten millennia of hepatitis B virus evolution

Hepatitis B virus (HBV) has been infecting humans for millennia and remains a global health problem, but its past diversity and dispersal routes are largely unknown. We generated HBV genomic data from 137 Eurasians and Native Americans dated between ~10,500 and ~400 years ago. We date the most recent common ancestor of all HBV lineages to between ~20,000 and 12,000 years ago, with the virus present in European and South American hunter-gatherers during the early Holocene. After the European Neolithic transition, Mesolithic HBV strains were replaced by a lineage likely disseminated by early farmers that prevailed throughout western Eurasia for ~4000 years, declining around the end of the 2nd millennium BCE. The only remnant of this prehistoric HBV diversity is the rare genotype G, which appears to have reemerged during the HIV pandemic

Teknik Mengeluarkan Gigi Fraktur Dengan Medah dan Cepat

ix, 52 hlm; 14*21 c

textbook of geriatric dentistry

577 hlm

textbook of geriatric dentistry

577 hlm

Positive short-term effects of sheep grazing on the alpine avifauna

Grazing by large herbivores may negatively affect bird populations. This is of great conservation concern in areas with intensive sheep grazing. Sheep management varies substantially between regions, but no study has been performed in less intensively grazed systems. In a fully replicated, landscape scale experiment with three levels of sheep grazing, we tested whether the abundance and diversity of an assemblage of mountain birds were negatively affected by grazing or if grazing facilitated the bird assemblage. Density of birds was higher at high sheep density compared with low sheep density or no sheep by the fourth grazing season, while there was no clear effect on bird diversity. Thus, agricultural traditions and land use politics determining sheep density may change the density of avifauna in either positive or negative directions

Synergies and trade-offs between ecosystem services in an alpine ecosystem grazed by sheep – An experimental approach

Domestic livestock drives ecosystem changes in many of the world’s mountain regions, and can be the dominant influenceon soil, habitat and wildlife dynamics. Grazing impacts on ecosystem services (ES) vary according to densities of sheep, butan ES framework accounting for these is lacking. We devised an experiment to evaluate synergies and trade-offs of ESs andcomponents of biodiversity affected by sheep density at the alpine landscape scale in southern Norway. We examined the effectsof increased (80 per km2), decreased (0 per km2) and maintained sheep densities (25 per km2) on ‘supporting’, ‘regulating’and ‘provisioning’ services and biodiversity (plants, invertebrates and birds). Overall, ESs and biodiversity were highest atmaintained sheep density. Regulating services, including carbon storage and habitat openness, were particularly favoured bymaintained densities of sheep. There was no overall decline in ESs from maintained to increased sheep densities, but severalservices, such as runoff water quality, plant productivity and carbon storage, declined when grazing increased. Our study providesexperimental evidence for a positive effect of grazing on ES, but only at maintained low sheep densities. By identifying ESand biodiversity components that are traded-off at decreased and increased grazing, our study also demonstrates some of thenegative impacts on ecosystems that can occur in mountain regions if management does not regulate herbivore densities. Herbivory; Ecosystem services; Livestock; Management; Optimal stocking levels; Overgrazing; Threshol