Genetic variation in eggshell crystal size and orientation is large and these traits are correlated with shell thickness and are associated with eggshell matrix protein markers

The size and orientation of calcium carbonate crystals influence the structure and strength of the eggshells of chickens. In this study, estimates of heritability were found to be high (0.6) for crystal size and moderate (0.3) for crystal orientation. There was a strong positive correlation (0.65) for crystal size and orientation with the thickness of the shell and, in particular, with the thickness of the mammillary layer. Correlations with shell breaking strength were positive but with a high standard error. This was contrary to expectations, as in man-made materials smaller crystals would be stronger. We believe the results of this study support the hypothesis that the structural organization of shell, and in particular the mammillary layer, is influenced by crystal size and orientation, especially during the initial phase of calcification. Genetic associations for crystal measurements were observed between haplotype blocks or individual markers for a number of eggshell matrix proteins. Ovalbumin and ovotransferrin (LTF) markers for example were associated with crystal size, while ovocleidin-116 and ovocalyxin-32 (RARRES1) markers were associated with crystal orientation. The location of these proteins in the eggshell is consistent with different phases of the shell-formation process. In conclusion, the variability of crystal size, and to a lesser extent orientation, appears to have a large genetic component, and the formation of calcite crystals are intimately related to the ultrastructure of the eggshell. Moreover, this study also provides evidence that proteins in the shell influence the variability of crystal traits and, in turn, the shell’s thickness profile. The crystal measurements and/or the associated genetic markers may therefore prove to be useful in selection programs to improve eggshell quality

Coherence of the posterior predictive p-value based on the posterior odds.

^aIt is well-known that classical p-values sometimes behave incoherently for testing hypotheses in the sense that, when $\Theta_{0} \subset \Theta_{0}{'}$, the support given to $\Theta_{0}$ is greater than or equal to the support given to $\Theta_{0}^{'}$ . This problem is also found for posterior predictive p-values (a Bayesian-motivated alternative to classical p-values). In this paper, it is proved that, under some conditions, the posterior predictive p-value based on the posterior odds is coherent, showing that the choice of a suitable discrepancy variable is crucial

On the Credibility of a Target Zone: Evidence from the EMS

We provide some new evidence on the credibility of the Exchange Rate Mechanism of the European Monetary System. To that end, we use of several credibility indicators, analysing the complete EMS history. We also compare the prediction qualities of the different indicators, and apply them to the experience of the new ERM linking the currencies of non-euro area Member States to the euro.Exchange rates, European Monetary System.

El progresismo pedagógico y el libro de texto.

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Soldadura por ultrasonidos de materiales compuestos : ventana de proceso CF-PEI

El objetivo de este proyecto es averiguar la ventana de proceso para el material CFPEI. Esto quiere decir, averiguar qué combinaciones de los parámetros que intervienen en el proceso, hacen que los resultados de la soldadura sean aceptables. Para ello, se realizarán tests de soldadura y ensayos mecánicos para obtener resultados como el tiempo de fusión, la máxima potencia, la energía consumida durante el proceso así como la resistencia de la unión. Para un mejor entendimiento se realizará también un estudio de la superficie de fractura de las muestras tras los ensayos mecánicos.Ingeniería Industria

Política y nihilismo.

Sin resume