819 research outputs found
The PAX Toolkit and its Applications at Tevatron and LHC
At the CHEP03 conference we launched the Physics Analysis eXpert (PAX), a C++
toolkit released for the use in advanced high energy physics (HEP) analyses.
This toolkit allows to define a level of abstraction beyond detector
reconstruction by providing a general, persistent container model for HEP
events. Physics objects such as particles, vertices and collisions can easily
be stored, accessed and manipulated. Bookkeeping of relations between these
objects (like decay trees, vertex and collision separation, etc.) including
deep copies is fully provided by the relation management. Event container and
associated objects represent a uniform interface for algorithms and facilitate
the parallel development and evaluation of different physics interpretations of
individual events. So-called analysis factories, which actively identify and
distinguish different physics processes and study systematic uncertainties, can
easily be realized with the PAX toolkit.
PAX is officially released to experiments at Tevatron and LHC. Being explored
by a growing user community, it is applied in a number of complex physics
analyses, two of which are presented here. We report the successful application
in studies of t-tbar production at the Tevatron and Higgs searches in the
channel t-tbar-Higgs at the LHC and give a short outlook on further
developments
Variable Selection in Latent Regression IRT Models via Knockoffs: An Application to International Large-scale Assessment in Education
International large-scale assessments (ILSAs) play an important role in
educational research and policy making. They collect valuable data on education
quality and performance development across many education systems, giving
countries the opportunity to share techniques, organizational structures, and
policies that have proven efficient and successful. To gain insights from ILSA
data, we identify non-cognitive variables associated with students' academic
performance. This problem has three analytical challenges: 1) academic
performance is measured by cognitive items under a matrix sampling design; 2)
there are many missing values in the non-cognitive variables; and 3) multiple
comparisons due to a large number of non-cognitive variables. We consider an
application to the Programme for International Student Assessment (PISA),
aiming to identify non-cognitive variables associated with students'
performance in science. We formulate it as a variable selection problem under a
general latent variable model framework and further propose a knockoff method
that conducts variable selection with a controlled error rate for false
selections
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Aerial river management by smart cross-border reforestation
In the face of increasing socio-economic and climatic pressures in growing cities, it is rational for managers to consider multiple approaches for securing water availability. One often disregarded option is the promotion of reforestation in source regions supplying important quantities of atmospheric moisture transported over long distances through aerial rivers, affecting water resources of a city via precipitation and runoff (âsmart reforestationâ). Here we present a case demonstrating smart reforestation's potential as a water management option. Using numerical moisture back-tracking models, we identify important upwind regions contributing to the aerial river of Santa Cruz de la Sierra (Bolivia). Simulating the effect of reforestation in the identified regions, annual precipitation and runoff reception in the city was found to increase by 1.25% and 2.30% respectively, while runoff gain during the dry season reached 26.93%. Given the city's population growth scenarios, the increase of the renewable water resource by smart reforestation could cover 22â59% of the additional demand by 2030. Building on the findings, we argue for a more systematic consideration of aerial river connections between regions in reforestation and land planning for future challenges. © 2019 The Author
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Landscape matters: Insights from the impact of mega-droughts on Colombia's energy transition
Mega-droughts can cause disruption to the affected society sparking a transition. We explore the causes and effects of the 2015â2016 mega-drought in Colombia. Using the multi-level perspective as a framework, we found that the mega-drought sparked an energy transition in Colombia whose dynamics were impacted both by the institutionalization of niches as well as the ability to predict the next drought. We were able to trace, using the current understanding of anthropogenic forces, the cause of the mega-drought to socio-technical landscape development influenced by human-induced warming and land use change. We found that the regimes in Bolivia and Brazil were able to influence the landscape through deforestation, and hence contribute to the intensity of a mega-drought in Colombia. The knowledge that a regime can cause disruption in regimes in other geographies and sectors has implications for transition research as well as decision-making for coping with droughts and other disasters. © 202
Recombinant hirudin for extended aortic surgery in patients with heparin-induced thrombocytopenia
AbstractJ Thorac Cardiovasc Surg 1999;118:191-
Reporter Assay for Endo/Lysosomal Escape of Toxin-Based Therapeutics
Protein-based therapeutics with cytosolic targets are capable of exhibiting
their therapeutic effect once they have escaped from the endosomes or
lysosomes. In this study, the reportersâhorseradish peroxidase (HRP), Alexa
Fluor 488 (Alexa) and ricin A-chain (RTA)âwere investigated for their capacity
to monitor the endo/lysosomal escape of the ribosome-inactivating protein,
saporin. The conjugatesâsaporin-HRP, Alexasaporin and saporin-KQ-RTAâwere
constructed, and the endo/lysosomal escape of these conjugates alone (lack of
endo/lysosomal release) or in combination with certain structurally-specific
triterpenoidal saponins (efficient endo/lysosomal escape) was characterized.
HRP failed in reporting the endo/lysosomal escape of saporin. Contrastingly,
Alexa Fluor 488 successfully allowed the report of the process at a toxin
concentration of 1000 nM. In addition, single endo/lysosome analysis
facilitated the determination of the amount of Alexasaporin released from each
vesicle. RTA was also successful in reporting the endo/lysosomal escape of the
enzymatically inactive mutant, saporin-KQ, but in this case, the sensitivity
of the method reached a toxin concentration of 10 nM. In conclusion, the
simultaneous usage of Alexa Fluor 488 and RTA as reporters may provide the
possibility of monitoring the endo/lysosomal escape of protein-based
therapeutics in the concentration range of 10â1000 nM. View Full-Tex
Plant Extracellular Vesicles and Nanovesicles: Focus on Secondary Metabolites, Proteins and Lipids with Perspectives on Their Potential and Sources
While human extracellular vesicles (EVs) have attracted a big deal of interest and have been extensively characterized over the last years, plant-derived EVs and nanovesicles have earned less attention and have remained poorly investigated. Although a series of investigations already revealed promising beneficial health effects and drug delivery properties, adequate (pre)clinical studies are rare. This fact might be caused by a lack of sources with appropriate qualities. Our study introduces plant cell suspension culture as a new and well controllable source for plant EVs. Plant cells, cultured in vitro, release EVs into the growth medium which could be harvested for pharmaceutical applications. In this investigation we characterized EVs and nanovesicles from distinct sources. Our findings regarding secondary metabolites indicate that these might not be packaged into EVs in an active manner but enriched in the membrane when lipophilic enough, since apparently lipophilic compounds were associated with nanovesicles while more hydrophilic structures were not consistently found. In addition, protein identification revealed a possible explanation for the mechanism of EV cell wall passage in plants, since cell wall hydrolases like 1,3-ÎČ-glucosidases, pectinesterases, polygalacturonases, ÎČ-galactosidases and ÎČ-xylosidase/α-L-arabinofuranosidase 2-like are present in plant EVs and nanovesicles which might facilitate cell wall transition. Further on, the identified proteins indicate that plant cells secrete EVs using similar mechanisms as animal cells to release exosomes and microvesicles
Antiferromagnetism in metals: from the cuprate superconductors to the heavy fermion materials
The critical theory of the onset of antiferromagnetism in metals, with
concomitant Fermi surface reconstruction, has recently been shown to be
strongly coupled in two spatial dimensions. The onset of unconventional
superconductivity near this critical point is reviewed: it involves a subtle
interplay between the breakdown of fermionic quasiparticle excitations on the
Fermi surface, and the strong pairing glue provided by the antiferromagnetic
fluctuations. The net result is a logarithm-squared enhancement of the pairing
vertex for generic Fermi surfaces, with a universal dimensionless co-efficient
independent of the strength of interactions, which is expected to lead to
superconductivity at the scale of the Fermi energy. We also discuss the
possibility that the antiferromagnetic critical point can be replaced by an
intermediate `fractionalized Fermi liquid' phase, in which there is Fermi
surface reconstruction but no long-range antiferromagnetic order. We discuss
the relevance of this phase to the underdoped cuprates and the heavy-fermion
materials.Comment: Talk at SCES 2011; 19 pages, 12 figures; (v2) corrected typo
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