2,130 research outputs found
Conflicting interests in the pathogen-host tug of war : fungal micronutrient scavenging versus mammalian nutritional immunity
Funding: The authors are supported by the European Research Council (STRIFE project funded on grant number ERC-2009-AdG-249793, http://erc.europa.eu). AJPB is also supported by the Wellcome Trust (grant numbers 080088, 097377, www.wellcome.ac.uk) and the UK Biotechnology and Biological Sciences Research Council (grant number BB/F00513X/1, www.bbsrc.ac.uk). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
New Clox Systems for rapid and efficient gene disruption in Candida albicans
Acknowledgements: We are grateful to Janet Quinn, Lila Kastora, Joanna Potrykus, Michelle Leach, and others for sharing their experiences with the Clox cassettes. We thank Julia Kohler for her kind gift of the NAT1-flipper plasmid pJK863, Claudia Jacob for her advice with In-fusion cloning, and our colleagues in the Aberdeen Fungal Group for numerous stimulating discussions. Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. The sequences of all Clox cassettes are available in GenBank: URA3-Clox (loxP-URA3-MET3p-cre-loxP): GenBank accession number KC999858. NAT1-Clox (loxP-NAT1-MET3p-cre-loxP): GenBank accession number KC999859. LAL (loxP-ARG4-loxP): GenBank accession number DQ015897. LHL (loxP-HIS1-loxP): GenBank accession number DQ015898. LUL (loxP-URA3-loxP): GenBank accession number DQ015899. Funding: This work was supported by the Wellcome Trust (www.wellcome.ac.uk): S.S., F.C.O., N.A.R.G., A.J.P.B. (080088); N.A.R.G., A.J.P.B. (097377). The authors also received support from the European Research Council [http://erc.europa.eu/]: DSC. ERB, AJPB (STRIFE Advanced Grant; C-2009-AdG-249793). The European Commission also provided funding [http://ec.europa.eu/research/fp7]: I.B., A.J.P.B. (FINSysB MC-ITN; PITN-GA-2008-214004). Also the UK Biotechnology and Biological Research Council provided support [www.bbsrc.ac.uk]: N.A.R.G., A.J.P.B. (Research Grant; BB/F00513X/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
A Spin Modulated Telescope to Make Two Dimensional CMB Maps
We describe the HEMT Advanced Cosmic Microwave Explorer (HACME), a balloon
borne experiment designed to measure sub-degree scale Cosmic Microwave
Background anisotropy over hundreds of square degrees, using a unique two
dimensional scanning strategy. A spinning flat mirror that is canted relative
to its spin axis modulates the direction of beam response in a nearly
elliptical path on the sky. The experiment was successfully flown in February
of 1996, achieving near laboratory performance for several hours at float
altitude. A map free of instrumental systematic effects is produced for a 3.5
hour observation of 630 square degrees, resulting in a flat band power upper
limit of (l(l+1)C_l/2 pi)^0.5 < 77 microK at l = 38 (95% confidence). The
experiment design, flight operations and data, including atmospheric effects
and noise performance, are discussed.Comment: 4 pages, 3 figure
Host-Imposed Copper Poisoning Impacts Fungal Micronutrient Acquisition during Systemic Candida albicans Infections
This work was supported by the European Research Council (http://erc.europa.eu/: STRIFE Advanced Grant ERC-2009-AdG-249793). A.J.P.B. was also supported by the UK Biotechnology and Biological Research Council (www.bbsrc.ac.uk: Research Grants BB/F00513X/1, BB/K017365/1), the UK Medical Research Council (www.mrc.ac.uk: Programme Grant MR/M026663/1; Centre Grant MR/ N006364/1), and the Wellcome Trust (www.wellcome.ac.uk: Strategic Award 097377)Peer reviewedPublisher PD
Ecosystem resistance in the face of climate change: a case study from the freshwater marshes of the Florida Everglades
Shaped by the hydrology of the Kissimmee-Okeechobee-Everglades watershed, the Florida Everglades is composed of a conglomerate of wetland ecosystems that have varying capacities to sequester and store carbon. Hydrology, which is a product of the region’s precipitation and temperature patterns combined with water management policy, drives community composition and productivity. As shifts in both precipitation and air temperature are expected over the next 100 years as a consequence of climate change, CO2 dynamics in the greater Everglades are expected to change. To reduce uncertainties associated with climate change and to explore how projected changes in atmospheric CO2 concentration and climate can alter current CO2 exchange rates in Everglades freshwater marsh ecosystems, we simulated fluxes of carbon among the atmosphere, vegetation, and soil using the DAYCENT model. We explored the effects of low, moderate, and high scenarios for atmospheric CO2 (550, 850, and 950 ppm), mean annual air temperature (þ1, þ2.5, and þ4.28C) and precipitation (2, þ7, and þ14%), as predicted by the IPCC for the year 2100 for the region, on CO2 exchange rates in short- and long-hydroperiod wetland ecosystems. Under 100 years of current climate and atmospheric CO2 concentration, Everglades freshwater marsh ecosystems were estimated to be CO2-neutral. As atmospheric CO2 concentration increased and under climate change projections, there were slight shifts in the start and length of the wet season (1 to þ7 days) and a small enhancement in the sink capacity (by 169 to 573 g C m2 century1 ) occurred at both short- and longhydroperiod ecosystems compared to CO2 dynamics under the current climate regime. Over 100 years, rising temperatures increased net CO2 exchange rates (þ1 to 13 g C m2 century1 ) and shifts in precipitation patterns altered cumulative net carbon uptake by þ13 to 46 g C m2 century1 . While changes in ecosystem structure, species composition, and disturbance regimes were beyond the scope of this research, results do indicate that climate change will produce small changes in CO2 dynamics in Everglades freshwater marsh ecosystems and suggest that the hydrologic regime and oligotrophic conditions of Everglades freshwater marshes lowers the ecosystem sensitivity to climate change. Key word
Elemental energy spectra of cosmic rays measured by CREAM-II
We present new measurements of the energy spectra of cosmic-ray (CR) nuclei
from the second flight of the balloon-borne experiment CREAM (Cosmic Ray
Energetics And Mass). The instrument (CREAM-II) was comprised of detectors
based on different techniques (Cherenkov light, specific ionization in
scintillators and silicon sensors) to provide a redundant charge identification
and a thin ionization calorimeter capable of measuring the energy of cosmic
rays up to several hundreds of TeV. The data analysis is described and the
individual energy spectra of C, O, Ne, Mg, Si and Fe are reported up to ~ 10^14
eV. The spectral shape looks nearly the same for all the primary elements and
can be expressed as a power law in energy E^{-2.66+/-0.04}. The nitrogen
absolute intensity in the energy range 100-800 GeV/n is also measured.Comment: 4 pages, 3 figures, presented at ICRC 2009, Lodz, Polan
Measurements of cosmic-ray energy spectra with the 2nd CREAM flight
During its second Antarctic flight, the CREAM (Cosmic Ray Energetics And
Mass) balloon experiment collected data for 28 days, measuring the charge and
the energy of cosmic rays (CR) with a redundant system of particle
identification and an imaging thin ionization calorimeter. Preliminary direct
measurements of the absolute intensities of individual CR nuclei are reported
in the elemental range from carbon to iron at very high energy.Comment: 4 pages, 3 figures, presented at XV International Symposium on Very
High Energy Cosmic Ray Interactions (ISVHECRI 2008
The Quantum Hall Effect in Drag: Inter-layer Friction in Strong Magnetic Fields
We study the Coulomb drag between two spatially separated electron systems in
a strong magnetic field, one of which exhibits the quantum Hall effect. At a
fixed temperature, the drag mimics the behavior of in the quantum
Hall system, in that it is sharply peaked near the transitions between
neighboring plateaux. We assess the impact of critical fluctuations near the
transitions, and find that the low temperature behavior of the drag measures an
exponent that characterizes anomalous low frequency dissipation; the
latter is believed to be present following the work of Chalker.Comment: 13 pages, Revtex 2.0, 1 figure upon request, P-93-11-09
Energy spectra of cosmic-ray nuclei at high energies
We present new measurements of the energy spectra of cosmic-ray (CR) nuclei
from the second flight of the balloon-borne experiment Cosmic Ray Energetics
And Mass (CREAM). The instrument included different particle detectors to
provide redundant charge identification and measure the energy of CRs up to
several hundred TeV. The measured individual energy spectra of C, O, Ne, Mg,
Si, and Fe are presented up to eV. The spectral shape looks
nearly the same for these primary elements and it can be fitted to an power law in energy. Moreover, a new measurement of the absolute
intensity of nitrogen in the 100-800 GeV/ energy range with smaller errors
than previous observations, clearly indicates a hardening of the spectrum at
high energy. The relative abundance of N/O at the top of the atmosphere is
measured to be (stat.)(sys.) at 800
GeV/, in good agreement with a recent result from the first CREAM flight.Comment: 32 pages, 10 figures. Accepted for publication in Astrophysical
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