1,507 research outputs found
Generalized Artin–Mumford curves over finite fields
Let Fq be the finite field of order q=ph with p>2 prime and h>1, and let Fq¯ be a subfield of Fq. From any two q¯-linearized polynomials L1,L2∈F‾q[T] of degree q, we construct an ordinary curve X(Ljavax.xml.bind.JAXBElement@3de21171,Ljavax.xml.bind.JAXBElement@44e73174) of genus g=(q−1)2 which is a generalized Artin–Schreier cover of the projective line P1. The automorphism group of X(Ljavax.xml.bind.JAXBElement@265fda03,Ljavax.xml.bind.JAXBElement@5ee20ea3) over the algebraic closure F‾q of Fq contains a semidirect product Σ⋊Γ of an elementary abelian p-group Σ of order q2 by a cyclic group Γ of order q¯−1. We show that for L1≠L2, Σ⋊Γ is the full automorphism group Aut(X(Ljavax.xml.bind.JAXBElement@4b2f1fff,Ljavax.xml.bind.JAXBElement@2ddc4e9)) over F‾q; for L1=L2 there exists an extra involution and Aut(X(Ljavax.xml.bind.JAXBElement@2daa9e77,Ljavax.xml.bind.JAXBElement@1c89ae0d))=Σ⋊Δ with a dihedral group Δ of order 2(q¯−1) containing Γ. Two different choices of the pair L1,L2 may produce birationally isomorphic curves, even for L1=L2. We prove that any curve of genus (q−1)2 whose F‾q-automorphism group contains an elementary abelian subgroup of order q2 is birationally equivalent to X(Ljavax.xml.bind.JAXBElement@1301e61e,Ljavax.xml.bind.JAXBElement@61aac551) for some separable q¯-linearized polynomials L1,L2 of degree q. We produce an analogous characterization in the special case L1=L2. This extends a result on the Artin–Mumford curves, due to Arakelian and Korchmáros [1]
Complete (k,3)-arcs from quartic curves
Complete (Formula presented.) -arcs in projective planes over finite fields are the geometric counterpart of linear non-extendible Near MDS codes of length (Formula presented.) and dimension (Formula presented.). A class of infinite families of complete (Formula presented.) -arcs in (Formula presented.) is constructed, for (Formula presented.) a power of an odd prime (Formula presented.). The order of magnitude of (Formula presented.) is smaller than (Formula presented.). This property significantly distinguishes the complete (Formula presented.) -arcs of this paper from the previously known infinite families, whose size differs from (Formula presented.) by at most (Formula presented.)
Non-minimum tensor rank Gabidulin codes
The tensor rank of some Gabidulin codes of small dimension is investigated. In particular, we determine the tensor rank of any rank metric code equivalent to an 8-dimensional Fq-linear generalized Gabidulin code in Fq4×4. This shows that such a code is never minimum tensor rank. In this way, we detect the first infinite family of Gabidulin codes which are not minimum tensor rank
On maximal curves that are not quotients of the Hermitian curve
For each prime power ℓ the plane curve Xℓwith equation Yℓ2ℓ+1=Xℓ2-X is maximal over Fℓ6. Garcia and Stichtenoth in 2006 proved that X3is not Galois covered by the Hermitian curve and raised the same question for Xℓwith ℓ>3; in this paper we show that Xℓis not Galois covered by the Hermitian curve for any ℓ>3. Analogously, Duursma and Mak proved that the generalized GK curve Cℓnover Fℓ2nis not a quotient of the Hermitian curve for ℓ>2 and n≥5, leaving the case ℓ=2 open; here we show that C2nis not Galois covered by the Hermitian curve over F22nfor n≥5
Brain air embolism secondary to atrial-esophageal fistula.
Case report of a patient who developed a cerebral air embolism secondary to atrial-esophageal fistula
Harmonic load-flow approach based on the possibility theory
Harmonics in power systems are responsible for several technical problems that justify the development of models to study them. Well-established models exist to analyse the harmonic load-flow (HLF) from a deterministic point of view. Moreover, models based on the probability theory have been developed to deal with the inherent variability and random nature of loads, network configuration etc. In the last few years, possibility theory has arisen as an alternative tool that in many cases could be better suited to describe and quantify the real nature of the uncertainty involved in harmonic studies. In this study a methodology for HLF calculation based on the possibility theory is presented. Possibility distributions instead of probabilities are the input used to describe the uncertainty in the magnitude and composition of the loads. Tests presented shows that the results of the proposed model are consistent with those obtained with a probabilistic method, and that both models lead to the same ranking of the risk that the bus harmonic voltages exceed a given level. Independent possibility distributions are assumed at the development stage reported here; research is being carried out in order to overcome this constraint.Fil: Romero Quete, Andrés Arturo. Universidad Nacional de San Juan. Facultad de IngenierÃa. Instituto de EnergÃa Eléctrica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - San Juan; ArgentinaFil: Zini, Humberto Cassiano. Universidad Nacional de San Juan. Facultad de IngenierÃa. Instituto de EnergÃa Eléctrica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - San Juan; ArgentinaFil: Rattá, G.. Universidad Nacional de San Juan. Facultad de IngenierÃa. Instituto de EnergÃa Eléctrica; ArgentinaFil: Dib, R.. No especifÃca
Non-invasive methodological approach to detect and characterize high-risk sinkholes in urban cover evaporite karst: Integrated reflection seismics, PS-INSAR, leveling, 3D-GPR and ancillary data. a Ne Italian case study
Sinkholes linked to cover evaporite karst in urban environments still represent a challenge in terms of their clear identification and mapping considering the rehash and man-made structures. In the present research, we have proposed and tested a methodology to identify the subsiding features through an integrated and non-invasive multi-scale approach combining seismic reflection, PS-InSAR (PSI), leveling and full 3D Ground Penetrating Radar (GPR), and thus overpassing the limits of each method. The analysis was conducted in a small village in the Alta Val Tagliamento Valley (Friuli Venezia Giulia region, NE Italy). Here, sinkholes have been reported for a long time as well as the hazards linked to their presence. Within past years, several houses have been demolished and at present many of them are damaged. The PSI investigation allowed the identification of an area with higher vertical velocities; seismic reflection imagined the covered karst bedrock, identifying three depocenters; leveling data presented a downward displacement comparable with PSI results; 3D GPR, applied here for the first time in the study and characterization of sinkholes, defined shallow sinking features. Combining all the obtained results with accurate field observations, we identified and mapped the highest vulnerable zone
CONVERGENCE OF SIGNALING BY INTERLEUKIN-3, GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR, AND MAST CELL GROWTH FACTOR ON JAK2 TYROSINE KINASE
Mast cell growth factor (MGF) (also called stem cell factor) synergizes with several lymphokines, including interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF), to promote proliferation and differentiation of certain hemopoietic progenitor cells. Although similar patterns of tyrosine-phosphorylated proteins characterize cells stimulated by MGF, IL-3, and GM-CSF, only the MGF receptor is a tyrosine kinase, and the heterodimeric receptors for IL-3 and GM-CSF share a common beta subunit that is devoid of enzymatic activity. Here we show that signaling pathways utilized by all three cytokines include the cytoplasmic tyrosine kinase JAK2. Analysis of several factor-dependent myeloid cell lines indicated that JAK2 is physically associated with the common beta subunit and with MGF receptor (c-Kit) even prior to ligand binding. However, each of the ligands induced elevated tyrosine phosphorylation of JAK2 and a consequent increase in its catalytic activity. These results demonstrate for the first time the convergence within the same myeloid cells of signaling pathways originating in two distinct lymphokine receptors and a tyrosine kinase receptor on activation of a cytoplasmic tyrosine kinase
Influence of high-protein and high-carbohydrate diets on serum lipid and fructosamine concentrations in healthy cats
Objectives: The aim of this study was to determine whether high-protein and high-carbohydrate diets exert differential effects on serum cholesterol, triglyceride and fructosamine concentrations in healthy cats. Methods A randomised, crossover diet trial was performed in 35 healthy shelter cats. Following baseline health assessments, cats were randomised into groups receiving either a high-protein or high-carbohydrate diet for 4 weeks. The cats were then fed a washout diet for 4 weeks before being transitioned to whichever of the two studied diets they had not yet received. Fasting serum cholesterol, triglyceride and fructosamine concentrations were determined at the end of each 4-week diet period. Results Cats on the high-carbohydrate diet had significantly lower serum cholesterol ( P 5) had lower cholesterol ( P = 0.007) and triglyceride ( P = 0.032) concentrations on the high-protein diet than cats within other BCS groups. Conclusions and relevance Diets higher in protein and lower in carbohydrates appear beneficial for short-term glucose control in healthy cats. A high-protein diet was associated with significantly elevated cholesterol and triglyceride concentrations in healthy cats, even though the increase was significantly less pronounced in cats with a BCS >5. This finding suggests that overweight cats process high-protein diets, cholesterol and triglycerides differently than leaner cats
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