A comparative study compiled from a survey taken in Middleton, Rhode Island concerning educational experiences for preschool children in the home,

Thesis (M.A.)--Boston Universit

Spatially correlated mixed-effects models for the analysis of soil water retention.

The knowledge of hydraulic properties of soil is necessary in many environmental applications and land planning. These properties, however, are difficult to determine and often they demand high labour costs, for which the tendency is to estimate them on the base of other more easily measurable or already available soil data. The level of detail reached using this method is not always satisfactory for some applications to basin scale, where variables to measure the morphologic property of the landscape are required. This study is proposed to characterize the spatial distribution of the water retention of a soil on wide scale using data relative to the physical, topographical and chemical characteristics of the soil within a model based approach.Linear Mixed Models, Spatial Continuous Autoregressive Correlation Structure, Soil Water Retention.

I modelli geo-additivi per l'analisi del grado di salinita' di un suolo

: In questo studio un modello geo-additivo e' stato utilizzato per analizzare la distribuzione spaziale del tasso di assorbimento del sodio nella zona costiera di Muravera-Villaputzu (CA) per individuare le cause che ne hanno determinato leccessivo grado di salinita', dannoso per le colture agrumicole praticate nella zona. I modelli geo-additivi rappresentano unevoluzione del kriging universale e consentono di considerare esplicitamente i legami non lineari tra la risposta e le covariate e la correlazione spaziale descritta mediante una funzione di autocorrelazione.

Scale-dependent maximum reinforcement percentage in reinforced concrete beams

The Cohesive/Overlapping Crack Model is able to describe the transition between cracking and crushing failures occurring in reinforced concrete beams by increasing beam depth and/or steel percentage. Within this Nonlinear Fracture Mechanics model, the tensile and compressive ultimate behaviors of the concrete matrix are modeled through two different process zones that advance independently one of another. Moreover, this model is able to investigate local mechanical instabilities occurring in the structural behavior of reinforced concrete structures: tensile snap-back and snap-through, which are due to concrete cracking or steel fracture, and the compressive snap-back occurring at the end of the plastic plateau, which is generated by the unstable growth of the crushing zone. In this context, the application of the Cohesive/Overlapping Crack Model highlights that the ductility, which is represented by the plastic rotation capacity of a reinforced concrete element subjected to bending, decreases as reinforcement percentage and/or beam depth increase. Thus, a scale-dependent maximum reinforcement percentage beyond which concrete crushing occurs prior to steel yielding is demonstrated to exist. In particular, the maximum steel percentage results to be inversely proportional to h0.25, h being the beam depth. In this way, a rational and quantitative definition of over-reinforcement is provided as a steel percentage depending on the beam depth

Scale-dependent maximum reinforcement percentage in reinforced concrete beams

AbstractThe Cohesive/Overlapping Crack Model is able to describe the transition between cracking and crushing failures occurring in reinforced concrete beams by increasing beam depth and/or steel percentage. Within this Nonlinear Fracture Mechanics model, the tensile and compressive ultimate behaviors of the concrete matrix are modeled through two different process zones that advance independently one of another. Moreover, this model is able to investigate local mechanical instabilities occurring in the structural behavior of reinforced concrete structures: tensile snap‐back and snap‐through, which are due to concrete cracking or steel fracture, and the compressive snap‐back occurring at the end of the plastic plateau, which is generated by the unstable growth of the crushing zone. In this context, the application of the Cohesive/Overlapping Crack Model highlights that the ductility, which is represented by the plastic rotation capacity of a reinforced concrete element subjected to bending, decreases as reinforcement percentage and/or beam depth increase. Thus, a scale‐dependent maximum reinforcement percentage beyond which concrete crushing occurs prior to steel yielding is demonstrated to exist. In particular, the maximum steel percentage results to be inversely proportional to h0.25, h being the beam depth. In this way, a rational and quantitative definition of over‐reinforcement is provided as a steel percentage depending on the beam depth

Body composition in clinical practice

Nutritional status is the results of nutrients intake, absorption and utilization, able to influence physiological and pathological conditions. Nutritional status can be measured for individuals with different techniques, such as CT Body Composition, quantitative Magnetic Resonance Imaging, Ultrasound, Dual-Energy X-Ray Absorptiometry and Bioimpendance. Because obesity is becoming a worldwide epidemic, there is an increasing interest in the study of body composition to monitor conditions and delay in development of obesity-related diseases. The emergence of these evidence demonstrates the need of standard assessment of nutritional status based on body weight changes, playing an important role in several clinical setting, such as in quantitative measurement of tissues and their fluctuations in body composition, in survival rate, in pathologic condition and illnesses. Since body mass index has been shown to be an imprecise measurement of fat-free and fat mass, body cell mass and fluids, providing no information if weight changes, consequently there is the need to find a better way to evaluate body composition, in order to assess fat-free and fat mass with weight gain and loss, and during ageing. Monitoring body composition can be very useful for nutritional and medical interventional. This review is focused on the use of Body Composition in Clinical Practice