1,711 research outputs found
Compact magneto-optical sources of slow atoms
Three different configurations of compact magneto-optical sources of slow Rb
atoms(LVIS, 2D(+)-MOT and 2D-MOT) were compared with each other at fixed
geometry of cooling laser beams. A precise control of the intensity balances
between the four separate transverse cooling laser beams provided a total
continuous flux of cold atoms from the LVIS and 2D(+)-MOT sources about 8x10^9
atoms/s at total laser power of 60 mW. The flux was measured directly from the
loading rate of a 3D-MOT, placed 34 cm downstream from the sources. Average
velocities of the cooled atomic beam for the LVIS and 2D(+)-MOT sources were
about 8.5 m/s and 11 m/s respectively. An essential advantage of the compact
magneto-optical sources is that their background flux of thermal atoms is two
to three orders of the magnitude smaller than the flux of slow atoms.Comment: 12 pages, 10 figures. to be published in Optics Communication
Real particle physics analysis by UK secondary school students using the ATLAS Open Data: an illustration through a collection of original student research
Since the 2020 release of 10fb-1 of integrated luminosity of protonâproton collision data to the public by the ATLAS experiment, significant potential for its use for youth engagement in physics and citizen science has been present. In particular, this article aims to address whether, if provided adequate training and resources, high school students are capable of leveraging the ATLAS Open Data to semi-autonomously develop their own original research projects. To this end, a repository of interactive Python Jupyter notebook training materials was developed, incrementally increasing in difficulty; in the initial instalments no prior knowledge of particle physics or Python coding is assumed, while in the latter stages students emulate the steps of a real Higgs boson search using ATLAS data. This programme was implemented in secondary schools throughout the UK during the 2022/23 academic year and is presented in this article through a collection of research projects developed by a selection of participating students
Fitness costs of animal medication: antiparasitic plant chemicals reduce fitness of monarch butterfly hosts
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134230/1/jane12558_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134230/2/jane12558.pd
Characterization of wild and captive baboon gut microbiota and their antibiotic resistomes
Antibiotic exposure results in acute and persistent shifts in the composition and function of microbial communities associated with vertebrate hosts. However, little is known about the state of these communities in the era before the widespread introduction of antibiotics into clinical and agricultural practice. We characterized the fecal microbiota and antibiotic resistomes of wild and captive baboon populations to understand the effect of human exposure and to understand how the primate microbiota may have been altered during the antibiotic era. We used culture-independent and bioinformatics methods to identify functional resistance genes in the guts of wild and captive baboons and show that exposure to humans is associated with changes in microbiota composition and resistome expansion compared to wild baboon groups. Our results suggest that captivity and lifestyle changes associated with human contact can lead to marked changes in the ecology of primate gut communities.Environmental microbes have harbored the capacity for antibiotic production for millions of years, spanning the evolution of humans and other vertebrates. However, the industrial-scale use of antibiotics in clinical and agricultural practice over the past century has led to a substantial increase in exposure of these agents to human and environmental microbiota. This perturbation is predicted to alter the ecology of microbial communities and to promote the evolution and transfer of antibiotic resistance (AR) genes. We studied wild and captive baboon populations to understand the effects of exposure to humans and human activities (e.g., antibiotic therapy) on the composition of the primate fecal microbiota and the antibiotic-resistant genes that it collectively harbors (the âresistomeâ). Using a culture-independent metagenomic approach, we identified functional antibiotic resistance genes in the gut microbiota of wild and captive baboon groups and saw marked variation in microbiota architecture and resistomes across habitats and lifeways. Our results support the view that antibiotic resistance is an ancient feature of gut microbial communities and that sharing habitats with humans may have important effects on the structure and function of the primate microbiota
Seroprevalence of Zika virus in wild African green monkeys and baboons
ABSTRACT Zika virus (ZIKV) has recently spread through the Americas and has been associated with a range of health effects, including birth defects in children born to women infected during pregnancy. Although the natural reservoir of ZIKV remains poorly defined, the virus was first identified in a captive âsentinelâ macaque monkey in Africa in 1947. However, the virus has not been reported in humans or nonhuman primates (NHPs) in Africa outside Gabon in over a decade. Here, we examine ZIKV infection in 239 wild baboons and African green monkeys from South Africa, the Gambia, Tanzania, and Zambia using combinations of unbiased deep sequencing, quantitative reverse transcription-PCR (qRT-PCR), and an antibody capture assay that we optimized using serum collected from captive macaque monkeys exposed to ZIKV, dengue virus, and yellow fever virus. While we did not find evidence of active ZIKV infection in wild NHPs in Africa, we found variable ZIKV seropositivity of up to 16% in some of the NHP populations sampled. We anticipate that these results and the methodology described within will help in continued efforts to determine the prevalence, natural reservoir, and transmission dynamics of ZIKV in Africa and elsewhere. IMPORTANCE Zika virus (ZIKV) is a mosquito-borne virus originally discovered in a captive monkey living in the Zika Forest of Uganda, Africa, in 1947. Recently, an outbreak in South America has shown that ZIKV infection can cause myriad health effects, including birth defects in the children of women infected during pregnancy. Here, we sought to investigate ZIKV infection in wild African primates to better understand its emergence and spread, looking for evidence of active or prior infection. Our results suggest that up to 16% of some populations of nonhuman primate were, at some point, exposed to ZIKV. We anticipate that this study will be useful for future studies that examine the spread of infections from wild animals to humans in general and those studying ZIKV in primates in particular. Podcast: A podcast concerning this article is available
Compact, Robust Source of Cold Atoms for Efficient Loading of a Magnetic Guide
We report a compact (<20cm3), robust source for producing a bright flux of
cold atoms, which can be loaded efficiently into a magnetic guide. A continuous
flux of up to 8 x 109 87Rb atoms/s have been produced from this 2D+ vapor cell
MOT. The flux had a divergence of 12.5 mrad and velocity could be controlled in
the range 2-15 m/s. This flux was coupled continuously into a magnetic guide
with high efficiency.Comment: 20 pages, 4 figure
Total syntheses of linear polythiazole/oxazole plantazolicin A and its biosynthetic precursor plantazolicin B.
Plantazolicinâ
A, a linear decacyclic natural product, exhibits desirable selective activity against the causative agent of anthrax toxicity. The total synthesis of plantazolicinâ
A and its biosynthetic precursor plantazolicinâ
B was successfully achieved by an efficient, unified, and highly convergent route featuring dicyclizations to form 2,4-concatenated oxazoles and the mild synthesis of thiazoles from natural amino acids. This report represents the first synthesis of plantazolicinâ
B and includes the first complete characterization data for both natural products.We gratefully acknowledge Prof. D. A. Mitchell (University of Illinois
at Urbana-Champaign) for providing an authentic sample of
plantazolicin A and advice on purification, Peter Grice and Duncan
Howe for assistance with NMR spectroscopy, and generous funding
from the Royal Society (Newton International FellowshipâZ.E.W.),
the German Academic Exchange Service DAAD (S.F.), and the
Engineering and Physical Sciences Research Council.This is the final version. It was first published by Wiley at http://onlinelibrary.wiley.com/doi/10.1002/anie.201410063/abstrac
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