3,147 research outputs found
Discrete concavity and the half-plane property
Murota et al. have recently developed a theory of discrete convex analysis
which concerns M-convex functions on jump systems. We introduce here a family
of M-concave functions arising naturally from polynomials (over a field of
generalized Puiseux series) with prescribed non-vanishing properties. This
family contains several of the most studied M-concave functions in the
literature. In the language of tropical geometry we study the tropicalization
of the space of polynomials with the half-plane property, and show that it is
strictly contained in the space of M-concave functions. We also provide a short
proof of Speyer's hive theorem which he used to give a new proof of Horn's
conjecture on eigenvalues of sums of Hermitian matrices.Comment: 14 pages. The proof of Theorem 4 is corrected
Quantum Pieri rules for isotropic Grassmannians
We study the three point genus zero Gromov-Witten invariants on the
Grassmannians which parametrize non-maximal isotropic subspaces in a vector
space equipped with a nondegenerate symmetric or skew-symmetric form. We
establish Pieri rules for the classical cohomology and the small quantum
cohomology ring of these varieties, which give a combinatorial formula for the
product of any Schubert class with certain special Schubert classes. We also
give presentations of these rings, with integer coefficients, in terms of
special Schubert class generators and relations.Comment: 59 pages, LaTeX, 6 figure
Exposing Issues and Challenges in Performance of Cloud Computing Services.
In current era of high performance computing, cloud computing is considered as new paradigm of ubiquitous computing. Peoples are changing their views and accordingly demand of consumer services for real world applications is getting diversified. Most of all global IT leader companies have started to consume cloud services in one or another way by putting their demands. The cloud is rapidly maturing towards its goal to satisfy federated need of consumer’s need for real-world applications. It is tried to reflect survey of current research related to open issues associated with clouds service performance with consideration of maintenance of performance and quality management and also simulates service level agreement based testing on the large scale commercial testing environment. One of the key aspect of the existing approach is it cloud environment need to achieve more flexibility to satisfy diversified users need and providers service delivery model. A collaborative system shall apply the concept of the cloud service performance testing to reduce the mitigations in cloud data and loss of the service availability and data integrity aspects
Efficacy, tolerability and safety of biologic therapy in rheumatoid disease: patient considerations
Rheumatoid arthritis (RA) is a systemic inflammatory disease in which chronic inflammation leads to joint destruction and extra-articular complications. Early and effective inhibition of inflammation is critical in order to prevent the progressive joint damage that occurs rapidly after onset of the disease. In the past, treatment for this purpose was limited to conventional disease-modifying antirheumatic drugs (DMARDs), which were often suboptimal. Within the last decade however, the development of biologic therapies, targeted against cytokines and cells involved in the inflammatory process, has revolutionized the management of RA. Disease remission is now an achievable goal in newly diagnosed patients. Since the advent of the first tumor necrosis factor-α inhibitor in 1999, other biologics have proved necessary as individuals respond to varying degrees with different therapies. Several are now available for the treatment of patients with RA that remains active despite DMARD treatment. This article reviews the evidence, over the last decade, of the efficacy and safety of biologic therapies used in this context, and the recent clinical data supporting the use of biologic therapy earlier in the disease process as first-line therapy
Abatacept in the treatment of rheumatoid arthritis
T-cell biology has regained importance in the pathogenesis of rheumatoid arthritis. Despite the significant improvements associated with the introduction of tumor necrosis factor-α blockade, reasonable proportions of failures and suboptimal responses have been reported, necessitating a search for alternative targeted therapies. This has included drug therapy designed to interrupt T-cell activation via the co-stimulation pathway. Abatacept is a recombinant fusion protein that blocks the co-stimulatory signal mediated by the CD28-CD80/86 pathway, which is required for T-cell activation. Several clinical trials have confirmed the safety and efficacy of this drug in the treatment of rheumatoid arthritis. This review summarizes the clinical data supporting this line of treatment and considers the safety and efficacy data from phase II and III trials
Stable Grothendieck polynomials and K-theoretic factor sequences
We formulate a nonrecursive combinatorial rule for the expansion of the stable Grothendieck polynomials of [Fomin-Kirillov '94] in the basis of stable Grothendieck polynomials for partitions. This gives a common generalization, as well as new proofs of the rule of [Fomin-Greene '98] for the expansion of the stable Schubert polynomials into Schur polynomials, and the K-theoretic Grassmannian Littlewood-Richardson rule of [Buch '02]. The proof is based on a generalization of the Robinson-Schensted and Edelman-Greene insertion algorithms. Our results are applied to prove a number of new formulas and properties for K-theoretic quiver polynomials, and the Grothendieck polynomials of [Lascoux-Schutzenberger '82]. In particular, we provide the first -theoretic analogue of the factor sequence formula of [Buch-Fulton '99] for the cohomological quiver polynomials
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