1,228 research outputs found
The geodesic flow of the BGPP metric is Liouville integrable
We prove that the geodesics equations corresponding to the BGPP metric are
integrable in the Liouville sense. The symmetry of
the model allows to reduce the system from four to two degrees of freedom.
Moreover, solutions of the reduced system and its degenerations can be solved
explicitly or reduced to a certain quadrature. In degenerated cases BGPP metric
coincides with the Eguchi-Hanson metric and for this case the mentioned
quadrature can be calculated explicitly in terms of elliptic integrals.Comment: 14 pages, one figur
Some Orthogonal Polynomials Related to Elliptic Functions
AbstractWe characterize the orthogonal polynomials in a class of polynomials defined through their generating functions. This led to three new systems of orthogonal polynomials whose generating functions and orthogonality relations involve elliptic functions. The Hamburger moment problems associated with these polynomials are indeterminate. We give infinite families of weight functions in each case. The different polynomials treated in this work are also polynomials in a parameter and as functions of this parameter they are orthogonal with respect to unique measures, which we find explicitly. Through a quadratic transformation we find a new exactly solvable birth and death process with quartic birth and death rates
Quantum integrability of quadratic Killing tensors
Quantum integrability of classical integrable systems given by quadratic
Killing tensors on curved configuration spaces is investigated. It is proven
that, using a "minimal" quantization scheme, quantum integrability is insured
for a large class of classic examples.Comment: LaTeX 2e, no figure, 35 p., references added, minor modifications. To
appear in the J. Math. Phy
A miniprep procedure for isolating genomic DNA from Magnoporthe grisea
We have developed a simple miniprep procedure for the isolation of genomic DNA from the ascomycete Magnaporthe grisea. This pathogen of many grasses, including rice, has a moderate growth rate and produces intermediate to low numbers of conidia when grown in culture. Thus, in our previous DNA preparation procedure we inoculated swirling liquid cultures with mycelium that had been fragmented in a blender rather than with conidia. The mycelium obtained from these cultures was ground in liquid nitrogen for DNA extraction. Though the quantity and quality of DNA obtained by this method is satisfactory, the technique is too laborious for analysis of many strains. We developed the procedure described below to eliminate the need to fragment mycelium in a blender to inoculate cultures and to eliminate the need to grind mycelium in liquid nitrogen for DNA extraction. The new procedure, which relies on the enzymatic removal of cell walls and the lysis of protoplasts, should be readily adaptable to other filamentous fungi with growth characteristics similar to those of M. grisea
A series of vectors for fungal transformation
We report a new fungal selectable marker that confers resistance to chlorimuron ethyl, a sulfonylurea herbicide. This gene as well as genes that confer resistance to hygromycin and bialaphos have been engineered to be compact and to eliminate sites for most common restriction enzymes. These three selectable markers have been used to construct a series of vectors for fungal transformation
Mastocytosis: a Rare Case of Anaphylaxis in Paediatric Age and Literature Review
The term “mastocytosis” denotes a heterogeneous group of disorders characterised by abnormal growth and accumulation of mast cells (MC) in one
or more organ systems. Symptoms result from MC chemical mediator’s release, pathologic infiltration of neoplastic MC in tissues or both. Multiple molecular, genetic and chromosomal defects seem to contribute
to an autonomous growth, but somatic c-kit
D816V mutation is more frequently encountered, especially in systemic disease.
We present a literature review of mastocytosis and a rare case report of an 18 month-old-girl with a bullous dermatosis, respiratory distress and anaphylaxis,
as clinical manifestations of mastocytosis.
The developments of accepted classification systems and novel useful markers allowed a re-evaluation and updating of the classification of mastocytosis.
In paediatric age cutaneous forms of disease
prevail and may regress spontaneously. SM is more frequently diagnosed in adults and is a persistent(clonal) disease of bone marrow. The clinical course in these patients is variable.Today diagnostic criteria for each disease variant are reasonably well defined. There are, however, peculiarities,
namely in paediatric age, that makes the diagnostic approach difficult. Systemic disease may pose differential diagnostic problems resulting from multiple organ systems involvement. Coversly, the “unexplained” appearance of those symptoms with no skin lesions should raise the suspicion of MC disease. This case is reported in order to stress the clinical
severity and difficult diagnostic approach that paediatric mastocytosis may assume
Determinants of credit risk: a multiple linear regression analysis of Peruvian municipal savings banks
In order to identify the determinants that influence the credit risk of Peruvian municipal savings banks, this quantitative research uses a nonexperimental design and a longitudinal sample to analyze monthly data corresponding to macroeconomic variables and microfinance institutions? internal variables from 2011 to 2020. Using multiple linear regression, the results show that the interest rate, unemployment rate, and liquidity ratio positively influence the credit risk of Peruvian municipal savings banks; the study also shows that gross domestic product, efficiency of administrative expenses, solvency, and coverage of provisions exert a negative influence on credit risk. It is concluded that seven of the eight independent variables studied influence the credit risk of Peruvian municipal savings banks; only the inflation variable does not significantly influence credit risk
Conidial Morphogenesis and Septin-Mediated Plant Infection Require Smo1, a Ras GTPase-Activating Protein in Magnaporthe oryzae
The pathogenic life cycle of the rice blast fungus Magnaporthe oryzae involves a series of morphogenetic changes, essential for its ability to cause disease. The smo mutation was identified > 25 years ago, and affects the shape and development of diverse cell types in M. oryzae, including conidia, appressoria, and asci. All attempts to clone the SMO1 gene by map-based cloning or complementation have failed over many years. Here, we report the identification of SMO1 by a combination of bulk segregant analysis and comparative genome analysis. SMO1 encodes a GTPase-activating protein, which regulates Ras signaling during infection-related development. Targeted deletion of SMO1 results in abnormal, nonadherent conidia, impaired in their production of spore tip mucilage. Smo1 mutants also develop smaller appressoria, with a severely reduced capacity to infect rice plants. SMO1 is necessary for the organization of microtubules and for septin-dependent remodeling of the F-actin cytoskeleton at the appressorium pore. Smol physically interacts with components of the Ras2 signaling complex, and a range of other signaling and cytoskeletal components, including the four core septins. SMO1 is therefore necessary for the regulation of RAS activation required for conidial morphogenesis and septin-mediated plant infection
Relativistic Elastostatics I: Bodies in Rigid Rotation
We consider elastic bodies in rigid rotation, both nonrelativistically and in
special relativity. Assuming a body to be in its natural state in the absence
of rotation, we prove the existence of solutions to the elastic field equations
for small angular velocity.Comment: 25 page
- …