19 research outputs found
Atom Optics Quantum Pendulum
We explain the dynamics of cold atoms, initially trapped and cooled in a
magneto-optic trap, in a monochromatic stationary standing electromagnetic wave
field. In the large detuning limit the system is modeled as a nonlinear quantum
pendulum. We show that wave packet evolution of the quantum particle probes
parametric regimes in the quantum pendulum which support classical period,
quantum mechanical revival and super revival phenomena. Interestingly, complete
reconstruction in particular parametric regime at quantum revival times is
independent of potential height.Comment: 14 pages, 7 figure
Pervasiveness of Parasites in Pollinators
Many pollinator populations are declining, with large economic and ecological
implications. Parasites are known to be an important factor in the some of the
population declines of honey bees and bumblebees, but little is known about the
parasites afflicting most other pollinators, or the extent of interspecific
transmission or vectoring of parasites. Here we carry out a preliminary
screening of pollinators (honey bees, five species of bumblebee, three species
of wasp, four species of hoverfly and three genera of other bees) in the UK for
parasites. We used molecular methods to screen for six honey bee viruses,
Ascosphaera fungi, Microsporidia, and
Wolbachia intracellular bacteria. We aimed simply to detect
the presence of the parasites, encompassing vectoring as well as actual
infections. Many pollinators of all types were positive for
Ascosphaera fungi, while Microsporidia were rarer, being
most frequently found in bumblebees. We also detected that most pollinators were
positive for Wolbachia, most probably indicating infection with
this intracellular symbiont, and raising the possibility that it may be an
important factor in influencing host sex ratios or fitness in a diversity of
pollinators. Importantly, we found that about a third of bumblebees
(Bombus pascuorum and Bombus terrestris)
and a third of wasps (Vespula vulgaris), as well as all honey
bees, were positive for deformed wing virus, but that this virus was not present
in other pollinators. Deformed wing virus therefore does not appear to be a
general parasite of pollinators, but does interact significantly with at least
three species of bumblebee and wasp. Further work is needed to establish the
identity of some of the parasites, their spatiotemporal variation, and whether
they are infecting the various pollinator species or being vectored. However,
these results provide a first insight into the diversity, and potential
exchange, of parasites in pollinator communities
Temporal Analysis of the Honey Bee Microbiome Reveals Four Novel Viruses and Seasonal Prevalence of Known Viruses, Nosema, and Crithidia
Honey bees (Apis mellifera) play a critical role in global food production as pollinators of numerous crops. Recently, honey bee populations in the United States, Canada, and Europe have suffered an unexplained increase in annual losses due to a phenomenon known as Colony Collapse Disorder (CCD). Epidemiological analysis of CCD is confounded by a relative dearth of bee pathogen field studies. To identify what constitutes an abnormal pathophysiological condition in a honey bee colony, it is critical to have characterized the spectrum of exogenous infectious agents in healthy hives over time. We conducted a prospective study of a large scale migratory bee keeping operation using high-frequency sampling paired with comprehensive molecular detection methods, including a custom microarray, qPCR, and ultra deep sequencing. We established seasonal incidence and abundance of known viruses, Nosema sp., Crithidia mellificae, and bacteria. Ultra deep sequence analysis further identified four novel RNA viruses, two of which were the most abundant observed components of the honey bee microbiome (∼1011 viruses per honey bee). Our results demonstrate episodic viral incidence and distinct pathogen patterns between summer and winter time-points. Peak infection of common honey bee viruses and Nosema occurred in the summer, whereas levels of the trypanosomatid Crithidia mellificae and Lake Sinai virus 2, a novel virus, peaked in January