2,060 research outputs found
Rapid retreat of permafrost coastline observed with aerial drone photogrammetry
Permafrost landscapes are changing around the Arctic in response to climate
warming, with coastal erosion being one of the most prominent and hazardous
features. Using drone platforms, satellite images, and historic aerial
photographs, we observed the rapid retreat of a permafrost coastline on
Qikiqtaruk â Herschel Island, Yukon Territory, in the Canadian Beaufort Sea.
This coastline is adjacent to a gravel spit accommodating several culturally
significant sites and is the logistical base for the Qikiqtaruk â Herschel
Island Territorial Park operations. In this study we sought to (i)Â assess
short-term coastal erosion dynamics over fine temporal resolution,
(ii)Â evaluate short-term shoreline change in the context of long-term
observations, and (iii)Â demonstrate the potential of low-cost lightweight
unmanned aerial vehicles (âdronesâ) to inform coastline studies and
management decisions. We resurveyed a 500 m permafrost coastal reach at high
temporal frequency (seven surveys over 40 d in 2017). Intra-seasonal
shoreline changes were related to meteorological and oceanographic variables
to understand controls on intra-seasonal erosion patterns. To put our
short-term observations into historical context, we combined our analysis of
shoreline positions in 2016 and 2017 with historical observations from 1952,
1970, 2000, and 2011. In just the summer of 2017, we observed coastal retreat
of 14.5 m, more than 6 times faster than the long-term average rate of
2.2±0.1 m aâ1 (1952â2017). Coastline retreat rates exceeded
1.0±0.1 m dâ1 over a single 4 d period. Over 40 d, we estimated
removal of ca. 0.96 m3 mâ1 dâ1. These findings highlight
the episodic nature of shoreline change and the important role of storm
events, which are poorly understood along permafrost coastlines. We found
drone surveys combined with image-based modelling yield fine spatial
resolution and accurately geolocated observations that are highly suitable to
observe intra-seasonal erosion dynamics in rapidly changing Arctic
landscapes.</p
CsI(Tl) Pulse Shape Discrimination with the Belle II Electromagnetic Calorimeter as a Novel Method to Improve Particle Identification at Electron-Positron Colliders
This paper describes the implementation and performance of CsI(Tl) pulse
shape discrimination for the Belle II electromagnetic calorimeter, representing
the first application of CsI(Tl) pulse shape discrimination for particle
identification at an electron-positron collider. The pulse shape
characterization algorithms applied by the Belle II calorimeter are described.
Control samples of , , , and are
used to demonstrate the significant insight into the secondary particle
composition of calorimeter clusters that is provided by CsI(Tl) pulse shape
discrimination. Comparisons with simulation are presented and provide further
validation for newly developed CsI(Tl) scintillation response simulation
techniques, which when incorporated with GEANT4 simulations allow the particle
dependent scintillation response of CsI(Tl) to be modelled. Comparisons between
data and simulation also demonstrate that pulse shape discrimination can be a
new tool to identify sources of improvement in the simulation of hadronic
interactions in materials. The efficiency and photon-as-hadron
fake-rate of a multivariate classifier that is trained to use pulse shape
discrimination is presented and comparisons are made to a shower-shape based
approach. CsI(Tl) pulse shape discrimination is shown to reduce the
photon-as-hadron fake-rate by over a factor of 3 at photon energies of 0.2 GeV
and over a factor 10 at photon energies of 1 GeV
Assessing the influence of the Responsibility to Protect on the UN Security Council during the Arab Spring
This article challenges those perspectives which assert first, that the Security Councilâs engagement with the Responsibility to Protect (R2P) during the Arab Spring evidences a generally positive trend, and second, that the response to the Arab Spring, particularly Syria, highlights the need for veto restraint. With respect to the first point, the evidence presented in this article suggests that the manner in which R2P has been employed by the Security Council during this period evidences three key trends: first, a willingness to invoke R2P only in the context of Pillar I; second, a pronounced lack of consensus surrounding Pillar III; and third, the persistent prioritisation of national interests over humanitarian concerns. With respect to veto restraint, this article argues that there is no evidence that this idea will have any significant impact on decision-making at the Security Council; the Councilâs response to the Arab Spring suggests that national interests continue to trump humanitarian need
Prevalence of enteropathogenic viruses and molecular characterization of group A rotavirus among children with diarrhea in Dar es Salaam Tanzania
Different groups of viruses have been shown to be responsible for acute diarrhea among children during their first few years of life. Epidemiological knowledge of viral agents is critical for the development of effective preventive measures, including vaccines. In this study we determined the prevalence of the four major enteropathogenic viruses - rotavirus, norovirus, adenovirus and astrovirus - was determined in 270 stool samples collected from children aged 0 - 60 months who were admitted with diarrhea in four hospitals in Dar es Salaam, Tanzania, using commercially available ELISA kits. In addition, the molecular epidemiology of group A rotavirus was investigated using reverse transcriptase multiplex polymerase chain reaction (RT-PCR). At least one viral agent was detected in 87/270 (32.2%) of the children. The prevalence of rotavirus, norovirus, adenovirus and astrovirus was 18.1%, 13.7%, 2.6% and 0.4%, respectively. In most cases (62.1%) of viruses were detected in children aged 7-12 months. The G and P types (VP7 and VP4 genotypes respectively) were further investigated in 49 rotavirus ELISA positive samples. G9 was the predominant G type (81.6%), followed by G1 (10.2%) and G3 (0.2%). P[8] was the predominant P type (83.7%), followed by P[6] (0.4%) and P[4] (0.2%). The following G and P types were not detected in this study population; G2, G4, G8 G10, P[9], P[10] and P[11]. The dominating G/P combination was G9P[8], accounting for 39 (90.7%) of the 43 fully characterized strains. Three (6.1%) of the 49 rotavirus strains could not be typed. Nearly one third of children with diarrhea admitted to hospitals in Dar es Salaam had one of the four viral agents. The predominance of rotavirus serotype G9 may have implication for rotavirus vaccination in Tanzania
The doctrine of the 'responsibility to protect' as a practice of political exceptionalism
The consensus on the doctrine of the âresponsibility to protectâ has replaced ideas of humanitarian intervention with a new vision of the responsibilities that states have to protect their peoples from the most egregious suffering. The contention of this article is that this is a politics of exceptionalism, whereby power is legitimated by reference to its effectiveness in responding to emergency or crisis. By analysing the doctrine in this way, new light is shed on the debate surrounding the responsibility to protect. First, understanding the doctrine in terms of exceptionalism helps explain the paradox of how the doctrine has been assimilated so readily into institutional and state practice without manifesting any greater commitment to international intervention. Second, understanding these new security practices in terms of exceptionalism allows us to move beyond questions of imperialism. Once understood in terms of exceptionalism, it can be shown that the stakes in the debate on the responsibility to protect are restricted not only to relations between states, but also to relations within them:
principles of representative government are to be substituted with paternalist and authoritarian visions of state power
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Are Patient Self-Reported Outcome Measures Sensitive Enough to Be Used as End Points in Clinical Trials?: Evidence from the United Kingdom Glaucoma Treatment Study
Purpose
The United Kingdom Glaucoma Treatment Study (UKGTS) demonstrated the effectiveness of an intraocular pressure-lowering drug in patients with glaucoma using visual field progression as a primary outcome. The present study tested the hypothesis that responses on patient-reported outcome measures (PROMs; secondary outcome measure) differ between patients receiving a topical prostaglandin analog (latanoprost) or placebo eye drops in UKGTS.
Design
Multicenter, randomized, triple-masked, placebo-controlled trial.
Participants
Newly diagnosed glaucoma patients in the UKGTS with baseline and exit PROMs (n = 182 and n = 168 patients from the treatment and placebo groups, respectively).
Methods
In the UKGTS (trial registration number, ISRCTN96423140), patients with open-angle glaucoma were allocated to receive latanoprost (treatment) or placebo; the observation period was 24 months. Patients completed general health PROMs (European Quality of Life in 5 Dimensions [EQ-5D] and 36-item Short Form [SF-36]) and PROMs specific to glaucoma (15-item Glaucoma Quality of Life [GQL-15] and 9-item Glaucoma Activity Limitation [GAL-9]) at baseline and exit from the trial. Percentage changes between measurement on PROMs were calculated for each patient and compared between treatment arms. In addition, differences between stable patients (n = 272) and those with glaucomatous progression (n = 78), as determined by visual field change (primary outcome), were assessed.
Main Outcome Measure
PROMs on health-related and vision-related quality of life.
Results
Average percentage change on PROMs was similar for patients in both arms of the trial, with no statistically significant differences between treatment and placebo groups (EQ-5D, P = 0.98; EQ-5D visual analog scale, P = 0.88; SF-36, P = 0.94, GQL-15, P = 0.66; GAL-9, P = 0.87). There were statistically significant differences between stable and progressing patients on glaucoma-specific PROMs (GQL-15, P = 0.02; GAL-9, P = 0.02), but not on general health PROMs (EQ-5D, P = 0.62; EQ-5D visual analog scale, P = 0.23; SF-36, P = 0.65).
Conclusions
Average change in PROMs on health-related and vision-related quality of life was similar for the treatment and placebo groups in the UKGTS. The PROMs used may not be sensitive enough to function as primary end points in clinical trials when participants have newly diagnosed early-stage glaucoma
Differential branching fraction and angular analysis of the decay B0âKâ0ÎŒ+ÎŒâ
The angular distribution and differential branching fraction of the decay B 0â K â0 ÎŒ + ÎŒ â are studied using a data sample, collected by the LHCb experiment in pp collisions at sâ=7 TeV, corresponding to an integrated luminosity of 1.0 fbâ1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions
Observation of the decay
The decay is observed for the first
time, using proton-proton collisions collected with the LHCb detector
corresponding to an integrated luminosity of 3fb. A signal yield of
decays is reported with a significance of 6.2 standard deviations.
The ratio of the branching fraction of \B_c \rightarrow J/\psi K^+ K^- \pi^+
decays to that of decays is measured to be
, where the first uncertainty is statistical and the
second is systematic.Comment: 18 pages, 2 figure
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