962 research outputs found
Stability properties of stochastic maximal Lp-regularity
No full textIn this paper we consider Lp-regularity estimates for solutions to stochastic evolution equations, which is called stochastic maximal Lp-regularity. Our aim is to find a theory which is analogously to Dore’s theory for deterministic evolution equations. He has shown that maximal Lp-regularity is independent of the length of the time interval, implies analyticity and exponential stability of the semigroup, is stable under perturbation and many more properties. We show that the stochastic versions of these results hold
Global well-posedness and interior regularity of 2D Navier–Stokes equations with stochastic boundary conditions
No full textThe paper is devoted to the analysis of the global well-posedness and the interior regularity of the 2D Navier–Stokes equations with inhomogeneous stochastic boundary conditions. The noise, white in time and coloured in space, can be interpreted as the physical law describing the driving mechanism on the atmosphere–ocean interface, i.e. as a balance of the shear stress of the ocean and the horizontal wind force.Analysi
de Caprariis D., Gravino A.E., Cerundolo R., Manna L.,Agresti A. Prime osservazioni in Europa di infezione associata a Rickettsia rickettsii nel cane: Descrizione di 10 casi
No full textSimple ways to interpret effects in modeling ordinal categorical data
No full textWe survey effect measures for models for ordinal categorical
data that can be simpler to interpret than the model parameters.
For describing the effect of an explanatory variable while adjusting
for other explanatory variables, we present probability-based
measures, including a measure of relative size and partial effect
measures based on instantaneous rates of change. We also discuss
summary measures of predictive power that are analogs of -squared
and multiple correlation for quantitative response variables. We
illustrate the measures for an example and provide { tfamily R}
code for implementing them
Simple ways to interpret effects in modeling binary data
No full textTraditional methods for the analysis of binary response data are generalized linear models that employ logistic or probit link functions. Unfortunately, effect measures for these type of models do not have a straightforward interpretation. Hence, in this paper we survey
probability-based effect measures that can be simpler to understand than logistic and probit regression model parameters and their corresponding effect measures, such as odds ratios. For describing the effect of an explanatory variable while adjusting for others, it is sometimes
possible to employ the identity and log link functions to generate simple effect measures. When such link functions are inappropriate, one can still construct analogous effect measures. For comparing groups that are levels of categorical explanatory variables or relevant values for quantitative explanatory variables, such measures can be based on average differences or log-ratios of the probability modeled. For quantitative explanatory variables, they can also be based on average instantaneous rates of change for the probability. We also propose
analogous measures for interpreting effects in models with nonlinear predictors, such as generalized additive models. We illustrate the measures for two examples and show how to implement them with R software
Distribution of repeated DNA families in the human genome
No full textBy means of restriction enzymes analysis and molecular hybridization, the distribution of repeated DNA families has been studied in the different DNA components into which the human genome can be fractionated by density gradient techniques. Three classes of DNA molecules have been analyzed: i) an homogeneous DNA component (satellite-like sequences; Q = 1.696 g/cm3, 3% of total DNA, AT repeated), ii) AT rich (Q = 1.698 g/cm3, 30% of total DNA, AT main-band) and GC rich (Q = 1.708 g/cm3, 6% of total DNA, GC main-band) DNA components. By this approach we have observed that Sau3A digestion of GC main-band gives rise to two bands of 75bp and 150bp, absent or under-represented in both AT rich DNA components. A preliminary characterization of these DNA fragments suggests that they contain one or more families of repeated sequences which fail to hybridize to EcoRI, HindIII and AluI families of repeats. In addition, we have observed that EcoRI sequences (alpha-RI DNA) are under-represented in GC main-band and show the same clustered organization in both AT rich DNA components
Interpreting Effects in Generalized Linear Modeling
No full textWith nonlinear link functions in generalized linear models, it can be difficult for nonstatisticians to understand how to interpret the estimated effects. For this purpose, it can be helpful to report approximate effects based on differences and ratios for the mean response. We illustrate with effect measures for models for categorical data. We mainly focus on binary response variables, showing how such measures can be simpler to interpret than logistic and probit regression model parameters and their corresponding effect measures, such as odds ratios. For describing the effect of an explanatory variable on a binary response while adjusting for others, it is sometimes possible to employ the identity and log link functions to generate simple effect measures. When such link functions are inappropriate, one can still construct analogous effect measures from standard models such as logistic regression. We also summarize recent literature on such effect measures for models for ordinal response variables. We illustrate the measures for two examples and show how to implement them with R software
Significance of ipsilateral breast tumor recurrence after breast conserving treatment : role of surgical removal
No full textOBJECTIVE:
To analyze the pattern over time (dynamics) of further recurrence and death after ipsilateral breast tumor recurrence (IBTR) in breast cancer patients undergoing breast conserving treatment (BCT).
METHODS:
A total of 338 evaluable patients experiencing IBTR were extracted from a database of 3,293 patients undergoing BCT. The hazard rates for recurrence and mortality throughout 10 years of follow-up after IBTR were assessed and were compared to the analogous estimates associated to the primary treatment.
RESULTS:
In a time frame with the time origin at the surgical treatment for IBTR, the hazard rate for further recurrence displays a bimodal pattern (peaks at the second and at the sixth year). Patients receiving mastectomy for IBTR reveal recurrence and mortality dynamics similar to that of node positive (N+) patients receiving mastectomy as primary surgery, apart from the first two-three years, when IBTR patients do worse. If the patients with time to IBTR longer than 2.5 years are considered, differences disappear.
CONCLUSIONS:
The recurrence and mortality dynamics following IBTR surgical removal is similar to the corresponding dynamics following primary tumor removal. In particular, patients with time to IBTR in excess of 2.5 years behave like N+ patients following primary tumor removal. Findings may be suitably explained by assuming that the surgical manoeuvre required by IBTR treatment is able to activate a sudden growing phase for tumor foci most of which, as suggested by the systemic model of breast cancer, would have reached the clinical level according to their own dynamics
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