87,786 research outputs found
Intraoperative Findings in Spinal Lesions
No full textUltrasonographic appearance of spinal tumors has been described in few studies until now, and the role of intraoperative ultrasound is not yet well standardized in spinal tumor surgery.
To evaluate the spinal cord, probes with very high frequency (10 MHz or greater) can be used with outstanding spatial and temporal resolution. Before tumor removal, the lesion is identified, measured on axial and sagittal axes and defined as hyperechoic, isoechoic, or hypoechoic. Other characteristics of the lesions are considered: presence of calcifications, cystic/necrotic areas, diffuse or circumscribed appearance, and the relationships with the surrounding anatomical structures. Intraoperative ultrasonographic findings of different spinal tumors, according to histotypes and also to position, with respective pictorial essays are here presented. Intraoperative ultrasound is a valuable tool to detect spinal lesions, evaluate the surgical approach, and plan the surgical strategy, considering the position and relationships of the lesion with bony, neural, and vascular structures
Esperienza didattica su un sistema idraulico: analisi del sistema e analogie con un circuito elettrico
No full textRelationship among explosive power, body fat, fat free mass, and pubertal development in youth soccer players. A preliminary study
No full textPurpose Changes in body size and functional capacities
are highly individual during puberty, and the performance
of a soccer player is often closely related to their maturity
status. The aim of the study was to evaluate the relationships
among explosive power, body fat, fat free mass and
pubertal development in young soccer players.
Methods Explosive power (countermovement jump—
CMJ), body mass index (BMI), percentage of body fat
(%BF), fat free mass (FFM) and a Self-Administered
Rating Scale for pubertal development (PDS) values of 11
‘‘Giovanissimi’’ (age 13 year), 13 ‘‘Allievi’’ (age 15 year)
and 10 ‘‘Juniores’’ (age [17 year) male soccer players
were compared. The statistical analysis was performed
using an analysis of variance among categories with
Fisher’s post hoc as appropriate. Furthermore, Pearson
correlations among variables were calculated considering
all subjects and also within categories.
Results Statistical differences emerged among categories
in CMJ (F(2,30) = 28.3, p\0.01), body fat weight (F(2,31) =
29.2, p\0.01) and PDS (F(2,29) = 18.5, p\0.01), while
%BF values showed statistical differences only for ‘‘Giovanissimi’’
and ‘‘Juniores’’ (F(2,31) = 3.4, p = 0.01). CMJ
showed significant correlations with FFM (r = 0.68) and
PDS (r = 0.63), PDS with FFM (r = 0.66) and BMI with
%BF(r = 0.71) and FFM (r = 0.71).A high correlation was
found within categories.
Conclusion Since we found differences between categories
and no correlation between chronological age and
pubertal status, this study highlights the importance of
assessing of puberty in youth soccer team
A mechanical ventilator with programmable flow waveforms
No full textA non-constant-flow generator for mechanical ventilation of the lungs is described
POD approach for unsteady aerodynamic model updating
No full textA method for aerodynamic model updating is proposed in this paper. The approach is based upon a correction of the eigenvalues of the reduced order unsteady aerodynamic matrix through an optimization with objective function defined through the difference in the generalized aerodynamic forces or on the aeroelastic poles. The high fidelity model in reduced order form is obtained by the Proper Orthogonal Decomposition (POD) technique applied to the Computational Fluid Dynamics (CFD) Euler-based formulation. Many of the methods that have been developed in the past years for simpler aeroelastic models that use, for example, doublet-lattice method (DLM) aerodynamics, can be adopted for this purpose as well. However, this model is not able to capture shocks and flow separation in transonic flow. The proposed approach performs the updating of the aerodynamic model by imposing the minimization of a global error between target aerodynamic performances, namely, experimental performances, and an aerodynamic model in reduced order form via POD approach. After a general presentation of the application of the POD method to the linearized Euler equations, the optimization strategy is presented. First a simple test on a 2D wing section with theoretical biased data is performed and then the performances of different optimization strategies are tested on a 3D model updated by Wind Tunnel data
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