1,619 research outputs found
Plant communities affect arbuscular mycorrhizal fungal diversity and community composition in grassland microcosms
The diversity of arbuscular mycorrhizal (AM) fungi was investigated in an unfertilized limestone grassland soil supporting different synthesized vascular plant assemblages that had developed for 3 yr. The experimental treatments comprised: bare soil; monocultures of the nonmycotrophic sedge Carex flacca; monocultures of the mycotrophic grass Festuca ovina; and a species-rich mixture of four forbs, four grasses and four sedges. The diversity of AM fungi was analysed in roots of Plantago lanceolata bioassay seedlings using terminal-restriction fragment length polymorphism (T-RFLP). The extent of AM colonization, shoot biomass and nitrogen and phosphorus concentrations were also measured. The AM diversity was affected significantly by the floristic composition of the microcosms and shoot phosphorus concentration was positively correlated with AM diversity. The diversity of AM fungi in P. lanceolata decreased in the order: bare soil > C. flacca > 12 species > F. ovina. The unexpectedly high diversity in the bare soil and sedge monoculture likely reflects differences in the modes of colonization and sources of inoculum in these treatments compared with the assemblages containing established AM-compatible plants
How fast is your detector? The effect of temporal response on image quality
With increasing interest in high-speed imaging, there should be an increased interest in the response times of our scanning transmission electron microscope detectors. Previous works have highlighted and contrasted the performance of various detectors for quantitative compositional or structural studies, but here, we shift the focus to detector temporal response, and the effect this has on captured images. The rise and decay times of eight detectors' single-electron response are reported, as well as measurements of their flatness, roundness, smoothness, and ellipticity. We develop and apply a methodology for incorporating the temporal detector response into simulations, showing that a loss of resolution is apparent in both the images and their Fourier transforms. We conclude that the solid-state detector outperforms the photomultiplier tube-based detectors in all areas bar a slightly less elliptical central hole and is likely the best detector to use for the majority of applications. However, using the tools introduced here, we encourage users to effectively evaluate which detector is most suitable for their experimental needs
Bino Dark Matter and Big Bang Nucleosynthesis in the Constrained E6SSM with Massless Inert Singlinos
We discuss a new variant of the E6 inspired supersymmetric standard model
(E6SSM) in which the two inert singlinos are exactly massless and the dark
matter candidate has a dominant bino component. A successful relic density is
achieved via a novel mechanism in which the bino scatters inelastically into
heavier inert Higgsinos during the time of thermal freeze-out. The two massless
inert singlinos contribute to the effective number of neutrino species at the
time of Big Bang Nucleosynthesis, where the precise contribution depends on the
mass of the Z' which keeps them in equilibrium. For example for mZ' > 1300 GeV
we find Neff \approx 3.2, where the smallness of the additional contribution is
due to entropy dilution. We study a few benchmark points in the constrained
E6SSM with massless inert singlinos to illustrate this new scenario.Comment: 24 pages, revised for publication in JHE
Decoupling Local Ownership? The Lost Opportunities for Grassroots Women’s Involvement in Liberian Peacebuilding
Civil society organizations and grassroots groups are often unable to play an active role in post-conflict reconstruction and peacebuilding. A possible explanation for the observed challenges in peacebuilding is the gap or decoupling between international expectations and norms from practical action, local norms and capacities. External actors are often overly instrumental and operate according to a general template that fails to start from what the local capacities might actually be. This often leads to the decoupling of general values from practical action, which helps account for the observed barriers of engaging local civil and community organizations in reconstruction. We examine the different types of decoupling and the challenges these present. We evaluate our general theoretical argument using evidence based on the experiences of Liberian women’s civil society organizations. Given the compliance of the Liberian government with international norms, we should expect external actors to have an easier task in incorporating civil society and women’s organizations in the post-conflict reconstruction process; yet, the record appears to be the opposite. While we present the ‘tragic’ aspect of this relationship between international norms and local practice, we also suggest opportunities for ‘hybrid’ alternatives
Agile : perspectives on Malta’s economy post COVID-19
Crises mark transitions and turning points. And it is
exactly at these turning points that crises are
productive. This is the moment when we can remove
the aftertaste of catastrophe and use it as a
“decisive turning point”, as per the meaning of the
Greek word krisis.
This is our belief too. As Seed, a new advisory and
research firm, we believe that this crisis can indeed
allow us to chart a new path. The seriousness of the
threat posed by COVID-19 demands us all to do
whatever it takes to weather the storm. Yet, our
biggest contribution to the future is to learn lessons
from our recent past and to change where necessary. We believe that agility is going to be the name
of the game. Only the employees, businesses,
governments and societies who are agile will survive
and thrive in the future.
We set up Seed wanting to do things differently. We
care about making a difference; for our employees,
for our clients and the wider community This
publication is our contribution to the current national
debate.
Our focus always goes beyond the short-term. Our
economic analysis is supplemented by a sentiment
survey we conducted together with local data
science company, Onest. We also
interviewed thirty-six business leaders and social
partners to get their perspectives too. In addition, our
analysis goes beyond the economic domain too. We
also have fourteen expert contributions spanning
different sectors and themes sharing their thoughts
on a post-COVID-19 world.
No doubt that the world will change. Business and
trade will change. Social dynamics and our way of
life will change. We need to start thinking of a new
normal. It is precisely for this reason, that our
recommendations go beyond the
immediate and offer a long-run vision for the
country.
We believe, more than ever, that this is the right time
to define our future. Let us together work on charting
an inclusive and sustainable economic model in the
long run; where quality is valued more than quantity,
where the environment is given its due importance
and where the economy works for people.
For this to start, we must start thinking. We must be
agile.
We hope that this publication can sow the seed of
discussion and debate on a new Malta.peer-reviewe
Cavity-enhanced coherent light scattering from a quantum dot.
The generation of coherent and indistinguishable single photons is a critical step for photonic quantum technologies in information processing and metrology. A promising system is the resonant optical excitation of solid-state emitters embedded in wavelength-scale three-dimensional cavities. However, the challenge here is to reject the unwanted excitation to a level below the quantum signal. We demonstrate this using coherent photon scattering from a quantum dot in a micropillar. The cavity is shown to enhance the fraction of light that is resonantly scattered toward unity, generating antibunched indistinguishable photons that are 16 times narrower than the time-bandwidth limit, even when the transition is near saturation. Finally, deterministic excitation is used to create two-photon N00N states with which we make superresolving phase measurements in a photonic circuit.Engineering and Physical Sciences Research CouncilThis is the final version of the article. It first appeared from the American Association for the Advancement of Science via http://dx.doi.org/10.1126/sciadv.150125
Evidence-based decision support for pediatric rheumatology reduces diagnostic errors.
BACKGROUND: The number of trained specialists world-wide is insufficient to serve all children with pediatric rheumatologic disorders, even in the countries with robust medical resources. We evaluated the potential of diagnostic decision support software (DDSS) to alleviate this shortage by assessing the ability of such software to improve the diagnostic accuracy of non-specialists.
METHODS: Using vignettes of actual clinical cases, clinician testers generated a differential diagnosis before and after using diagnostic decision support software. The evaluation used the SimulConsult® DDSS tool, based on Bayesian pattern matching with temporal onset of each finding in each disease. The tool covered 5405 diseases (averaging 22 findings per disease). Rheumatology content in the database was developed using both primary references and textbooks. The frequency, timing, age of onset and age of disappearance of findings, as well as their incidence, treatability, and heritability were taken into account in order to guide diagnostic decision making. These capabilities allowed key information such as pertinent negatives and evolution over time to be used in the computations. Efficacy was measured by comparing whether the correct condition was included in the differential diagnosis generated by clinicians before using the software ( unaided ), versus after use of the DDSS ( aided ).
RESULTS: The 26 clinicians demonstrated a significant reduction in diagnostic errors following introduction of the software, from 28% errors while unaided to 15% using decision support (p \u3c 0.0001). Improvement was greatest for emergency medicine physicians (p = 0.013) and clinicians in practice for less than 10 years (p = 0.012). This error reduction occurred despite the fact that testers employed an open book approach to generate their initial lists of potential diagnoses, spending an average of 8.6 min using printed and electronic sources of medical information before using the diagnostic software.
CONCLUSIONS: These findings suggest that decision support can reduce diagnostic errors and improve use of relevant information by generalists. Such assistance could potentially help relieve the shortage of experts in pediatric rheumatology and similarly underserved specialties by improving generalists\u27 ability to evaluate and diagnose patients presenting with musculoskeletal complaints.
TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT02205086
El Niño, tropical Atlantic warmth, and Atlantic hurricanes over the past 1500 years
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 460 (2009): 880-883, doi:10.1038/nature08219.Atlantic Tropical Cyclone (TC) activity, as measured by annual storm counts,
reached anomalous levels over the past decade. The short nature of the historical
record and potential issues with its reliability in earlier decades, however, has
prompted an ongoing debate regarding the reality and significance of the recent
rise. Here, we place recent activity in a longer-term context, by comparing two
independent estimates of TC activity over the past 1500 years. The first estimate is
based on a composite of regional sedimentary evidence of landfalling hurricanes,
while the second estimate employs a previously published statistical model of
Atlantic TC activity driven by proxy-reconstructions of past climate changes. Both
approaches yield consistent evidence of a peak in Atlantic TC activity during
Medieval times (around AD 1000) followed by a subsequent lull in activity. The
Medieval peak, which rivals or even exceeds (within uncertainties) recent levels of
activity, results in the statistical model from a ‘perfect storm’ of La Niña-like
climate conditions and relative tropical Atlantic warmth.M.E.M. and Z.Z. acknowledge support from the ATM programme of the National Science Foundation (grant ATM-0542356). J.P.D. acknowledges support from the EAR and OCE programmes of the National Science Foundation (grants EAR-0519118 and OCE-0402746), the Risk Prediction Initiative at the Bermuda Institute for Ocean Sciences, and the Inter-American Institute for Global Change Research
A bayesian meta-analysis of multiple treatment comparisons of systemic regimens for advanced pancreatic cancer
© 2014 Chan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: For advanced pancreatic cancer, many regimens have been compared with gemcitabine (G) as the standard arm in randomized controlled trials. Few regimens have been directly compared with each other in randomized controlled trials and the relative efficacy and safety among them remains unclear
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