2,621 research outputs found
Stratifying On-Shell Cluster Varieties: the Geometry of Non-Planar On-Shell Diagrams
The correspondence between on-shell diagrams in maximally supersymmetric
Yang-Mills theory and cluster varieties in the Grassmannian remains largely
unexplored beyond the planar limit. In this article, we describe a systematic
program to survey such 'on-shell varieties', and use this to provide a complete
classification in the case of . In particular, we find exactly 24
top-dimensional varieties and 10 co-dimension one varieties in ---up to
parity and relabeling of the external legs. We use this case to illustrate some
of the novelties found for non-planar varieties relative to the case of
positroids, and describe some of the features that we expect to hold more
generally.Comment: 35 pages, 70 figures, and 1 table; also included is a file with
explicit details for our classification. Signs corrected in two residue
theorems, and a new interpretation (and formula) given for the las
Supplier's total cost of ownership evaluation: a data envelopment analysis approach
Supplier Total Cost of Ownership (TCO) is a widely-known approach for determining the overall cost generated by a supplier relationship, but its adoption is still limited. The complex calculations involved - and in particular the activity-based costing procedure for computing the cost of managing the relationship - pose a major obstacle to widespread TCO implementation. The purpose of this work is to formulate a Data Envelopment Analysis application (denoted 'TCO-based DEA') that can act as a proxy for TCO, and to test its ability to approximate the results of TCO with less effort. The study is based on the analysis of two categories of suppliers (74 in total) of a medium-sized Italian mechanical engineering company. The results show that TCO-based DEA is able to significantly approximate the outcomes of TCO, for both the efficiency indexes and rankings of suppliers, whilst requiring substantially less effort to perform the analysis. To our knowledge, this is the first study to develop a DEA-based tool for approximating TCO and to test it in a real-world setting. The research shows significant potential within the supply chain management field. In particular, TCO-based DEA can be used for analysing suppliers' performance, rationalising and reducing the supplier base, assisting the negotiation process
Development of highly porous activated carbon from Jacaranda mimosifolia seed pods for remarkable removal of aqueous-phase ketoprofen
In this work, a high porous activated carbon from Jacaranda mimosifolia was developed and employed for ketoprofen adsorption. After the pyrolysis process at 973.15 K, the material presented cavities with different sizes allocated on the particle surface. The material presented a pH at the point of zero charge of 4.1 with the best adsorption at pH 2. The best adsorbent dosage was 0.72 g L−1, corresponding to a removal of 96%. The system reached the adsorption equilibrium after 120 min and was described by the linear driving force model. The isotherms revealed that the adsorption capacity decreased with the temperature and followed the Langmuir model, with a maximum adsorption capacity of 303.9 mg g−1. This high capacity can be associated with the high surface area (928 m2 g−1) and pore volume (0.521 cm3 g−1) values. The thermodynamic values indicated that the adsorption system is spontaneous and exothermic. The enthalpy value indicates that the interactions between the adsorbent and adsorbate are physical. Regeneration tests showed a decreasing percentage of removal of 7.86% after 5 cycles. Finally, the adsorbent showed efficiency when treating a simulated effluent containing drugs and inorganic salts, showing the removal of 71.43%
Induced sputum is a reproducible method to assess airway inflammation in asthma.
To evaluate the reproducibility of induced sputum analysis, and to estimate the sample size required to obtained reliable results, sputum was induced by hypertonic saline inhalation in 29 asthmatic subjects on two different days. The whole sample method was used for analysis, and inflammatory cells were counted on cytospin slides. Reproducibility, expressed by intra-class correlation coefficients, was good for macrophages (+0.80), neutrophils (+0.85), and eosinophils (+0.87), but not for lymphocytes (+0.15). Detectable differences were 5.5% for macrophages, 0.6% for lymphocytes, 5.2% for neutrophils, and 3.0% for eosinophils. We conclude that analysis of induced sputum is a reproducible method to study airway inflammation in asthma. Sample sizes greater than ours give little improvement in the detectable difference of eosinophil percentages
Surveys of potato-growing areas and surface water in Lebanon for potato brown and ring rot pathogens.
Field surveys were carried out over three growing seasons (2013\u20132015), in the main potato growing
areas of Lebanon, to assess the occurrence of potato brown rot caused by Ralstonia solanacearum and potato ring
rot caused by Clavibacter michiganensis subsp. sepedonicus. A total of 232 potato samples were collected from Bekaa
valley and 145 samples from Akkar plain, which are the largest Lebanese areas cropped with potatoes. Composite
samples of 200 potato tubers were randomly collected from each field, following procedures laid down in EU
legislation. Twelve potato demonstration fields were established in Akkar plain and designed for potato export to
European markets: these were also surveyed using the same strategy. Furthermore, a network of 40 sampling sites
in Bekaa and 19 sites in Akkar was established to collect surface water. GPS coordinates of potato fields and water
sampling sites were recorded to map specific sampling points using Geographic Information System. All samples
gave negative results for R. solanacearum and C. michiganensis subsp. sepedonicus in potatoes and R. solanacearum in
water, as indicated using the official EU methods for detection and diagnosis for these pathogens. A monitoring
system for R. solanacearum and C. michiganensis subsp. michiganensis has been set up in Lebanon. This will increase
the phytosanitary quality of potatoes and provide access to broader international markets
Unbalanced Holographic Superconductors and Spintronics
We present a minimal holographic model for s-wave superconductivity with
unbalanced Fermi mixtures, in 2+1 dimensions at strong coupling. The breaking
of a U(1)_A "charge" symmetry is driven by a non-trivial profile for a charged
scalar field in a charged asymptotically AdS_4 black hole. The chemical
potential imbalance is implemented by turning on the temporal component of a
U(1)_B "spin" field under which the scalar field is uncharged. We study the
phase diagram of the model and comment on the eventual (non) occurrence of
LOFF-like inhomogeneous superconducting phases. Moreover, we study "charge" and
"spin" transport, implementing a holographic realization (and a generalization
thereof to superconducting setups) of Mott's two-current model which provides
the theoretical basis of modern spintronics. Finally we comment on possible
string or M-theory embeddings of our model and its higher dimensional
generalizations, within consistent Kaluza-Klein truncations and brane-anti
brane setups.Comment: 45 pages, 15 figures; v2: two paragraphs below eq. (3.1) slightly
modified, figure 5 (left) replaced, references added; v3: typos corrected,
comments added, figure 12 replace
Induced sputum is a reproducible method to assess airway inflammation in asthma
TO evaluate the reproducibility of induced sputum analysis, and to estimate the sample size required to obtained reliable results, sputum was induced by hypertonic saline inhalation in 29 asthmatic subjects on two different days. The whole sample method was used for analysis, and inflammatory cells were counted on cytospin slides. Reproducibility, expressed by intra-class correlation coefficients, was good for macrophages (+0.80), neutrophils (+0.85), and eosinophils (+0.87), but not for lymphocytes (+0.15). Detectable differences were 5.5% for macrophages, 0.6% for lymphocytes, 5.2% for neutrophils, and 3.0% for eosinophils. We conclude that analysis of induced sputum is a reproducible method to study airway inflammation in asthma. Sample sizes greater than ours give little improvement in the detectable difference of eosinophil percentages
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