5,798 research outputs found
Enhanced Quantum Reflection of Matter-Wave Solitons
Matter-wave bright solitons are predicted to reflect from a purely attractive
potential well although they are macroscopic objects with classical
particle-like properties. The non-classical reflection occurs at small
velocities and a pronounced switching to almost perfect transmission above a
critical velocity is found, caused by nonlinear mean-field interactions. Full
numerical results from the nonlinear Schr\"{o}dinger equation are complimented
by a two-mode variational calculation to explain the predicted effect, which
can be used for velocity filtering of solitons. The experimental realization
with laser-induced potentials or two-component Bose-Einstein condensates is
suggested.Comment: 7 pages, 3 figures, to be published in Europhys. Let
Indigenous voices in climate change adaptation
AbstractThis project investigated how the deep knowledge of the Yorta Yorta people can be used to strengthen their participation and influence in the complex national and regional processes that determine how their traditional lands, which are in the highly-contested Murray-Darling Basin, are managed, leading to improved adaptation decisions both for the Yorta Yorta and the wider community.Through discussions with the Yorta Yorta over several years, the approach developed for the project was the creation of a Geographical Information System (GIS) mapping framework containing both Yorta Yorta knowledge and more conventional knowledge. GIS allows for mapping and layering of different types of data, allowing the Yorta Yorta to access and present their knowledge in ways that relate to Western decision-making processes. To do this, the project had four components:1. Development and testing of protocols and methodology for the collection and protection of Yorta Yorta knowledge. This was carried out through an intergenerational process, whereby Yorta Yorta youth were trained in cultural data collection techniques, and they interviewed Elders to capture the knowledge.2. Building of a GIS framework to integrate both the Yorta Yorta knowledge and more conventional data about the climate, hydrology and biodiversity of the Yorta Yorta area. For the first time this pulled together all of the conventional information normally used as a basis for natural resource management decisions. In addition, because the GIS database has been created and is owned by the Yorta Yorta means that they have something of value to bring to the discussions, so that they are able to participate in those discussions on equal terms.3. Exploration of the views of the broader community in the region regarding management of the region and adaptation alternatives through a stakeholder consultation process. The consultation identified the potential for greater use of science as a neutral arbiter in issues such as management of the Murray-Darling Basin, but even more important is the need for genuine, deep, open-minded dialogue with the community at all stages of decision-making, particularly at an early stage before proposals are put forward and views become entrenched.4. Identification of broader lessons for improving adaptation of First Nations communities in Australia from the experience of the Yorta Yorta and other communities around the country, through a national workshop. The key conclusion of the workshop was the urgent need to empower First Nation communities to make their own assessments and decisions on the best ways for them to respond to climate change.The project raised community awareness and knowledge and energised the Yorta Yorta youth to take an interest in their history and culture, and in the climate challenges facing their community. Overall the project has been a successful pilot demonstration of the utility of a GIS database to integrate Indigenous and conventional knowledge for better natural resource management outcomes and the project has increased the knowledge and capacity of the Yorta Yorta to engage in effective natural resource management and decision-making.Please cite this report as:Griggs, D, Lynch, A, Joachim, L, Zhu, X, Adler, C, Bischoff-Mattson, Z, Wang, P, Kestin, T 2013 Indigenous voices in climate change adaptation: Addressing the challenges of diverse knowledge systems in the Barmah-Millewa, National Climate Change Adaptation Research Facility, Gold Coast, pp.71AbstractThis project investigated how the deep knowledge of the Yorta Yorta people can be used to strengthen their participation and influence in the complex national and regional processes that determine how their traditional lands, which are in the highly-contested Murray-Darling Basin, are managed, leading to improved adaptation decisions both for the Yorta Yorta and the wider community.Through discussions with the Yorta Yorta over several years, the approach developed for the project was the creation of a Geographical Information System (GIS) mapping framework containing both Yorta Yorta knowledge and more conventional knowledge. GIS allows for mapping and layering of different types of data, allowing the Yorta Yorta to access and present their knowledge in ways that relate to Western decision-making processes. To do this, the project had four components:Development and testing of protocols and methodology for the collection and protection of Yorta Yorta knowledge. This was carried out through an intergenerational process, whereby Yorta Yorta youth were trained in cultural data collection techniques, and they interviewed Elders to capture the knowledge.Building of a GIS framework to integrate both the Yorta Yorta knowledge and more conventional data about the climate, hydrology and biodiversity of the Yorta Yorta area. For the first time this pulled together all of the conventional information normally used as a basis for natural resource management decisions. In addition, because the GIS database has been created and is owned by the Yorta Yorta means that they have something of value to bring to the discussions, so that they are able to participate in those discussions on equal terms.Exploration of the views of the broader community in the region regarding management of the region and adaptation alternatives through a stakeholder consultation process. The consultation identified the potential for greater use of science as a neutral arbiter in issues such as management of the Murray-Darling Basin, but even more important is the need for genuine, deep, open-minded dialogue with the community at all stages of decision-making, particularly at an early stage before proposals are put forward and views become entrenched.Identification of broader lessons for improving adaptation of First Nations communities in Australia from the experience of the Yorta Yorta and other communities around the country, through a national workshop. The key conclusion of the workshop was the urgent need to empower First Nation communities to make their own assessments and decisions on the best ways for them to respond to climate change.The project raised community awareness and knowledge and energised the Yorta Yorta youth to take an interest in their history and culture, and in the climate challenges facing their community. Overall the project has been a successful pilot demonstration of the utility of a GIS database to integrate Indigenous and conventional knowledge for better natural resource management outcomes and the project has increased the knowledge and capacity of the Yorta Yorta to engage in effective natural resource management and decision-making
Cavity optoelectromechanical regenerative amplification
Cavity optoelectromechanical regenerative amplification is demonstrated. An
optical cavity enhances mechanical transduction, allowing sensitive measurement
even for heavy oscillators. A 27.3 MHz mechanical mode of a microtoroid was
linewidth narrowed to 6.6\pm1.4 mHz, 30 times smaller than previously achieved
with radiation pressure driving in such a system. These results may have
applications in areas such as ultrasensitive optomechanical mass spectroscopy
Xenon excimer emission from multicapillary discharges in direct current mode
Microdischarges in xenon have been generated in a pressure range of 400–1013 mbar with a fixed flow rate of 100 sccm. These microdischarges are obtained from three metallic capillary tubes in series for excimer emission. Total discharge voltage is thrice as large as that of a single capillary discharge tube at current levels of up to 12 mA. Total spectral irradiance of vacuum ultraviolet (VUV) emission also increases significantly compared to that of the single capillary discharge. Further, the irradiance of the VUV emission is strongly dependent on pressure as well as the discharge current
Farthest-Polygon Voronoi Diagrams
Given a family of k disjoint connected polygonal sites in general position
and of total complexity n, we consider the farthest-site Voronoi diagram of
these sites, where the distance to a site is the distance to a closest point on
it. We show that the complexity of this diagram is O(n), and give an O(n log^3
n) time algorithm to compute it. We also prove a number of structural
properties of this diagram. In particular, a Voronoi region may consist of k-1
connected components, but if one component is bounded, then it is equal to the
entire region
Non-Gaussianity in the Weak Lensing Correlation Function Likelihood -- Implications for Cosmological Parameter Biases
We study the significance of non-Gaussianity in the likelihood of weak
lensing shear two-point correlation functions, detecting significantly non-zero
skewness and kurtosis in one-dimensional marginal distributions of shear
two-point correlation functions in simulated weak lensing data. We examine the
implications in the context of future surveys, in particular LSST, with
derivations of how the non-Gaussianity scales with survey area. We show that
there is no significant bias in one-dimensional posteriors of
and due to the non-Gaussian likelihood distributions of shear
correlations functions using the mock data ( deg). We also present a
systematic approach to constructing approximate multivariate likelihoods with
one-dimensional parametric functions by assuming independence or more flexible
non-parametric multivariate methods after decorrelating the data points using
principal component analysis (PCA). While the use of PCA does not modify the
non-Gaussianity of the multivariate likelihood, we find empirically that the
one-dimensional marginal sampling distributions of the PCA components exhibit
less skewness and kurtosis than the original shear correlation
functions.Modeling the likelihood with marginal parametric functions based on
the assumption of independence between PCA components thus gives a lower limit
for the biases. We further demonstrate that the difference in cosmological
parameter constraints between the multivariate Gaussian likelihood model and
more complex non-Gaussian likelihood models would be even smaller for an
LSST-like survey. In addition, the PCA approach automatically serves as a data
compression method, enabling the retention of the majority of the cosmological
information while reducing the dimensionality of the data vector by a factor of
5.Comment: 16 pages, 10 figures, published MNRA
Taste-Changing in Staggered Quarks
We present results from a systematic perturbative investigation of
taste-changing in improved staggered quarks. We show one-loop taste-changing
interactions can be removed perturbatively by an effective four-quark term and
calculate the necessary coefficients.Comment: 3 pages using espcrc2.sty and amsmath.sty, 1 Feynman diagram using
feynmp.sty for Lattice2002(improve
Proenkephalin, neutrophil gelatinase-associated lipocalin, and estimated glomerular filtration rates in patients with sepsis
Background: Proenkephalin (PENK) has been suggested as a novel biomarker for kidney function. We investigated the diagnostic and prognostic utility of plasma PENK in comparison with neutrophil gelatinase-associated lipocalin (NGAL) and estimated glomerular filtration rates (EGFR) in septic patients. Methods: A total of 167 septic patients were enrolled: 99 with sepsis, 37 with septic shock, and 31 with suspected sepsis. PENK and NGAL concentrations were measured and GFR was estimated by using the isotope dilution mass spectrometry traceable-Modification of Diet in Renal Disease (MDRD) Study and three Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations: CKD-EPICr, CDK-EPICysC, and CKD-EPICr-CysC. The PENK, NGAL, and EGFR results were compared according to sepsis severity, presence or absence of acute kidney injury (AKI), and clinical outcomes. Results: The PENK, NGAL, and EGFR results were significantly associated with sepsis severity and differed significantly between patients with and without AKI only in the sepsis group (all P<0.05). PENK was superior to NGAL in predicting AKI (P=0.022) and renal replacement therapy (RRT) (P=0.0085). Regardless of the variable GFR category by the different EGFR equations, PENK showed constant and significant associations with all EGFR equations. Unlike NGAL, PENK was not influenced by inflammation and predicted the 30-day mortality. Conclusions: PENK is a highly sensitive and objective biomarker of AKI and RRT and is useful for prognosis prediction in septic patients. With its diagnostic robustness and predictive power for survival, PENK constitutes a promising biomarker in critical care settings including sepsis
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