1,022 research outputs found
Governor Patrick Signs Bill to Control Health Care Costs
Surveys of foliar endophytes from the Acadian forest region over the past three decades have identified numerous phylogenetically diverse fungi producing natural products toxic to forest pests and diseases. The life histories of some conifer endophytes can be restricted to plant foliage or may include saprotrophic phases on other plants tissues or even alternate hosts. Considering the potentially broad host preferences of conifer endophytes we explored fungi isolated from understory species and their metabolites as part of an ongoing investigation of fungal biodiversity from the Acadian forest. We report a hitherto unidentified Xylariomycetidae species isolated from symptomatic Labrador tea (Rhododendron groenlandicum) leaves and mountain laurel (Kalmia latifolia) collected in coastal southern New Brunswick, Canada. Morphological and phylogenetic evidence demonstrated the unknown species was a novel Synnemapestaloides (Sporocadaceae) species, described here as Syn. ericacearum. A preliminary screening assay indicated that the culture filtrate extract of the new species was potently antifungal towards the biotrophic pathogen Microbotryum violaceum, warranting an investigation of its natural products. Two natural products possessing a rare 1,3-benzodioxin-4-one scaffold, synnemadoxins A-B (1-2), and their postulated precursor, synnemadiacid A (3), were characterized as new structures and assessed for antimicrobial activity. All isolated compounds elicited in vitro inhibitory antifungal activity towards M. violaceum at 2.3 μg mL-1 and moderate antibiotic activity. Further, the characterization of synnemadoxins A-B provided a perspective on the biosynthesis of some related 1,3-benzodioxin-4-ones produced by other fungi within the Xylariales
Correction of SOHO CELIAS/SEM EUV Measurements saturated by extreme solar flare events
The solar irradiance in the Extreme Ultraviolet (EUV) spectral bands has been
observed with a 15 sec cadence by the SOHO Solar EUV Monitor (SEM) since 1995.
During remarkably intense solar flares the SEM EUV measurements are saturated
in the central (zero) order channel (0.1 -- 50.0 nm) by the flare soft X-ray
and EUV flux. The first order EUV channel (26 -- 34 nm) is not saturated by the
flare flux because of its limited bandwidth, but it is sensitive to the arrival
of Solar Energetic Particles (SEP). While both channels detect nearly equal SEP
fluxes, their contributions to the count rate is sensibly negligible in the
zero order channel but must be accounted for and removed from the first channel
count rate. SEP contribution to the measured SEM signals usually follows the
EUV peak for the gradual solar flare events. Correcting the extreme solar flare
SEM EUV measurements may reveal currently unclear relations between the flare
magnitude, dynamics observed in different EUV spectral bands, and the measured
Earth atmosphere response. A simple and effective correction technique based on
analysis of SEM count-rate profiles, GOES X-ray, and GOES proton data has been
developed and used for correcting EUV measurements for the five extreme solar
flare events of July 14, 2000, October 28, November 2, November 4, 2003, and
January 20, 2005. Although none of the 2000 and 2003 flare peaks were
contaminated by the presence of SEPs, the January 20, 2005 SEPs were unusually
prompt and contaminated the peak. The estimated accuracy of the correction is
about 7.5% for large X-class events.Comment: To appear in Astron. Nachr. /A
Multi-level selectional stalemate in a simple artificial chemistry
We describe a simple artificial chemistry which abstracts a small number of key features from the origin of life "replicator world" hypotheses. We report how this can already give rise to moderately complex and counter-intuitive evolutionary phenomena, including macro- evolutionary deterioration in replication fidelity (which corresponds to intrinsic replicator fitness in this model). We briefly describe the extension of this model to incorporate a higher, protocell, level of selection. We
show that the interaction between the two levels of selection then serves to control parasitic exploitation at the molecular level, while still significantly constraining accessible evolutionary trajectories at the protocell level. We conclude with a brief discussion of the implications for further work
90GHz and 150GHz observations of the Orion M42 region. A sub-millimeter to radio analysis
We have used the new 90GHz MUSTANG camera on the Robert C. Byrd Green Bank
Telescope (GBT) to map the bright Huygens region of the star-forming region M42
with a resolution of 9" and a sensitivity of 2.8mJy/beam. 90GHz is an
interesting transition frequency, as MUSTANG detects both the free-free
emission characteristic of the HII region created by the Trapezium stars,
normally seen at lower frequencies, and thermal dust emission from the
background OMC1 molecular cloud, normally mapped at higher frequencies. We also
present similar data from the 150GHz GISMO camera taken on the IRAM telescope.
This map has 15" resolution. By combining the MUSTANG data with 1.4, 8, and
21GHz radio data from the VLA and GBT, we derive a new estimate of the emission
measure (EM) averaged electron temperature of Te = 11376K by an original method
relating free-free emission intensities at optically thin and optically thick
frequencies. Combining ISO-LWS data with our data, we derive a new estimate of
the dust temperature and spectral emissivity index within the 80" ISO-LWS beam
toward OrionKL/BN, Td = 42K and Beta=1.3. We show that both Td and Beta
decrease when going from the HII region and excited OMC1 interface to the
denser UV shielded part of OMC1 (OrionKL/BN, Orion S). With a model consisting
of only free-free and thermal dust emission we are able to fit data taken at
frequencies from 1.5GHz to 854GHz.Comment: 18 pages, 8 figures, submitted to the Astrophysical Journa
Assessing the terrestrial capacity for negative emission technologies in Ireland
Negative emissions technologies (NETs) and their potential role in meeting emission targets is a rapidly growing and contentious area of climate change mitigation research. The literature ranges in scope from general reviews of NETs options to research and development through applied case studies. Within this field, a gap exists in the application of this growing body of research to the unique limitations and opportunities of a specific nation. Ireland is a small developed island nation in the EU with a unique emissions profile, as 32% of the total comes from agriculture due to the high number of cattle. In this study we aim to assess the potential capacity of terrestrial NETs options for Ireland and review the nation-specific context for their deployment. Despite the proportionally high representation of biochar and carbon capture and storage in the international NETs research, in an Irish context afforestation and bioenergy crops are much more established practices and could readily be considered in possible emission pathways that use NETs. Higher capacities were found for NETs options that are currently unavailable (direct air carbon capture and storage and bioenergy with carbon capture and storage), while options available to deploy at scale (afforestation, soil carbon management and biochar) have capacities limited by saturation of soil carbon stock and have higher risk of reversibility due to impermanence. Hence, while we estimate a reasonable technical capacity for NETs in Ireland, emission reduction remains the highest priority for feasibly meeting a Paris-aligned carbon quota for Ireland
J.S. Bell's Concept of Local Causality
John Stewart Bell's famous 1964 theorem is widely regarded as one of the most
important developments in the foundations of physics. It has even been
described as "the most profound discovery of science." Yet even as we approach
the 50th anniversary of Bell's discovery, its meaning and implications remain
controversial. Many textbooks and commentators report that Bell's theorem
refutes the possibility (suggested especially by Einstein, Podolsky, and Rosen
in 1935) of supplementing ordinary quantum theory with additional ("hidden")
variables that might restore determinism and/or some notion of an
observer-independent reality. On this view, Bell's theorem supports the
orthodox Copenhagen interpretation. Bell's own view of his theorem, however,
was quite different. He instead took the theorem as establishing an "essential
conflict" between the now well-tested empirical predictions of quantum theory
and relativistic \emph{local causality}. The goal of the present paper is, in
general, to make Bell's own views more widely known and, in particular, to
explain in detail Bell's little-known mathematical formulation of the concept
of relativistic local causality on which his theorem rests. We thus collect and
organize many of Bell's crucial statements on these topics, which are scattered
throughout his writings, into a self-contained, pedagogical discussion
including elaborations of the concepts "beable", "completeness", and
"causality" which figure in the formulation. We also show how local causality
(as formulated by Bell) can be used to derive an empirically testable Bell-type
inequality, and how it can be used to recapitulate the EPR argument.Comment: 19 pages, 4 figure
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