Moduli spaces of toric manifolds

We construct a distance on the moduli space of symplectic toric manifolds of dimension four. Then we study some basic topological properties of this space, in particular, path-connectedness, compactness, and completeness. The construction of the distance is related to the Duistermaat-Heckman measure and the Hausdorff metric. While the moduli space, its topology and metric, may be constructed in any dimension, the tools we use in the proofs are four-dimensional, and hence so is our main result.Comment: To appear in Geometriae Dedicata, minor changes to previous version, 19 pages, 6 figure

Hamiltonian dynamics and spectral theory for spin-oscillators

We study the Hamiltonian dynamics and spectral theory of spin-oscillators. Because of their rich structure, spin-oscillators display fairly general properties of integrable systems with two degrees of freedom. Spin-oscillators have infinitely many transversally elliptic singularities, exactly one elliptic-elliptic singularity and one focus-focus singularity. The most interesting dynamical features of integrable systems, and in particular of spin-oscillators, are encoded in their singularities. In the first part of the paper we study the symplectic dynamics around the focus-focus singularity. In the second part of the paper we quantize the coupled spin-oscillators systems and study their spectral theory. The paper combines techniques from semiclassical analysis with differential geometric methods.Comment: 32 page

Extremal Graph Theory for Metric Dimension and Diameter

A set of vertices $S$ \emph{resolves} a connected graph $G$ if every vertex is uniquely determined by its vector of distances to the vertices in $S$. The \emph{metric dimension} of $G$ is the minimum cardinality of a resolving set of $G$. Let $\mathcal{G}_{\beta,D}$ be the set of graphs with metric dimension $\beta$ and diameter $D$. It is well-known that the minimum order of a graph in $\mathcal{G}_{\beta,D}$ is exactly $\beta+D$. The first contribution of this paper is to characterise the graphs in $\mathcal{G}_{\beta,D}$ with order $\beta+D$ for all values of $\beta$ and $D$. Such a characterisation was previously only known for $D\leq2$ or $\beta\leq1$. The second contribution is to determine the maximum order of a graph in $\mathcal{G}_{\beta,D}$ for all values of $D$ and $\beta$. Only a weak upper bound was previously known

A single-nucleotide polymorphism in the human p27(kip1 )gene (-838C>A) affects basal promoter activity and the risk of myocardial infarction

BACKGROUND: Excessive proliferation of vascular smooth muscle cells and leukocytes within the artery wall is a major event in the development of atherosclerosis. The growth suppressor p27(kip1 )associates with several cyclin-dependent kinase/cyclin complexes, thereby abrogating their capacity to induce progression through the cell cycle. Recent studies have implicated p27(kip1 )in the control of neointimal hyperplasia. For instance, p27(kip1 )ablation in apolipoprotein-E-null mice enhanced arterial cell proliferation and accelerated atherogenesis induced by dietary cholesterol. Therefore, p27(kip1 )is a candidate gene to modify the risk of developing atherosclerosis and associated ischaemic events (i.e., myocardial infarction and stroke). RESULTS: In this study we found three common single-nucleotide polymorphisms in the human p27(kip1 )gene (+326T>G [V109G], -79C>T, and -838C>A). The frequency of -838A carriers was significantly increased in myocardial infarction patients compared to healthy controls (odds ratio [OR] = 1.73, 95% confidence interval [95%CI] = 1.12–2.70). In addition, luciferase reporter constructs driven by the human p27(kip1 )gene promoter containing A at position -838 had decreased basal transcriptional activity when transiently transfected in Jurkat cells, compared with constructs bearing C in -838 (P = 0.04). CONCLUSIONS: These data suggest that -838A is associated with reduced p27(kip1 )promoter activity and increased risk of myocardial infarction

Estimation of genetic parameters for cheese-making traits in Spanish Churra sheep

Artículo de investigaciónThe global production of sheep milk is growing, and the main industrial use of sheep milk is cheese making. The Spanish Churra sheep breed is one of the most important native dairy breeds in Spain. The present study aimed to estimate genetic parameters for a wide range of traits influencing the cheese-making ability of Churra sheep milk. Using a total of 1,049 Churra ewes, we studied the following cheese-making traits: 4 traits related to milk coagulation properties (rennet coagulation time, curd-firming time, and curd firmness at 30 and 60 min after addition of rennet), 2 traits related to cheese yield (individual laboratory cheese yield and individual laboratory dried curd yield), and 3 traits measuring curd firmness over time (maximum curd firmness, time to attain maximum curd firmness, and syneresis). In addition, a list of milk traits, including the native pH of the milk and several milk production and composition traits (milk yield; the fat, protein, and dried extract percentages; and the somatic cell count), were also analyzed for the studied animals. After discarding the noncoagulating samples (only 3.7%), data of 1,010 ewes were analyzed with multiple-trait animal models by using the restricted maximum likelihood method to estimate (co)variance components, heritabilities, and genetic correlations. In general, the heritability estimates were low to moderate, ranging from 0.08 (for the individual laboratory dried curd yield trait) to 0.42 (for the fat percentage trait). High genetic correlations were found within pairs of related traits (i.e., 0.93 between fat and dried extract percentages, −0.93 between the log of the curd-firming time and curd firmness at 30 min, 0.70 between individual laboratory cheese yield and individual laboratory dried curd yield, and −0.94 between time to attain maximum curd firmness and syneresis). Considering all the information provided here, we suggest that in addition to the current consideration of the protein percentage trait for improving cheese yield traits, the inclusion of the pH of milk as a measured trait in the Churra dairy breeding program would represent an efficient strategy for improving the cheese-making ability of milk from this breed.S

Utilización de la densidad de incidencia, en la valoración de faciores de riesgo de la infección nosocomial

ResumenEn la literatura se han propuesto las medidas de densidad de incidencia para la valoración de la infección nosocomial. A través de una cohorte retrospectiva de 843 pacientes se realiza una comparación entre la razón de densidades de incidencia (RDI) y el cociente de incidencias acumuladas o riesgo relativo (RR) en la cuantificación de factores de riesgo de la infección hospitalaria. Las variables que se analizaron fueron la intervención quirúrgica, su duración, el tipo de cirugía, la gravedad de la enfermedad subyacente y la edad. En todas las situaciones la RDI fue inferior al RR, al eliminar la prolongación de estancia producida por los distintos factores de riesgo. Ejemplos de ello fueron el que la RDI para la operación fue de 2,78, mientras que el RR ofreció valores de 6,46, o en la edad, donde los mayores de 60 años presentaron un RR significativo de 1,67, mientras que la RDI fue de 0,96. Esto sugiere que el empleo de la RDI facilitaría la comparabilidad de los resultados entre diferentes centros en la cuantificación de factores de riesgo para la infección nosocomial, aparte de cuantificar con más exactitud los distintos factores de riesgo, lo que tiene importancia a la hora de establecer las medidas de control.SummarySeveral authors have suggested that incidence density should be used in studying nosocomial infection. We assess several risk factors for hospital infection by two ratios, the incidence density ratio (IDR) and the relative risk (RR), in an historical cohort of 843 patients. The variables analyzed were: operation, its length, type of surgical wound, severity of underlying disease, and age. The IDR figures were always lower than those yielded by the RR. For example, the IDR for operated patients was 2.78, whereas RR yielded a figure of 6.46, or the IDR for patients >60 years old was 0.96, whereas the RR achieved a significant value of 1.67. This suggests that the use of IDR lo analyze risk factors for nosocomial infection improves comparability of results obtained in different hospital settings. Also, it may allow a more exact quantification of an effect. These facts influence implementation of nosocomial infection control measures

Design and Manufacture of a Large-Bore 10 T Superconducting Dipole for the CERN Cable Test Facility

A large-bore 10 T superconducting dipole magnet was designed and fabricated in close cooperation between CERN and HMA Power Systems. The dipole has a length of about 1.7 m and an aperture of 88 mm and is composed of two two-layer poles wound with NbTi cables cooled to 1.9 K to reach magnetic inductions close to 10 T. This dipole will be installed at the CERN cable test facility and used as a background field magnet to test LHC superconducting cables. In its large aperture up to four cable samples can be tested at the same time. The mechanical design of the magnet is such that coil prestress variations between warm and cold conditions are kept within 20 MPa. A short model was also built and cooled down in order to check and confirm with test results the mechanical behavior of the dipole. Magnetic measurements, at room temperature, were performed upon its arrival at CERN prior to installation in the test facility. The dipole was recently cooled down and tested. This paper will discuss the design, the main manufacturing steps and the initial test results