Prenatal diagnosis of proximal focal femoral deficiency: Literature review of prenatal sonographic findings

Proximal focal femoral deficiency (PFFD) is a rare musculoskeletal malformation that occurs in 0.11-0.2 per 10,000 live births. This congenital anomaly involves the pelvis and proximal femur with widely variable manifestations, from mild femoral shortening and hypoplasia to the absence of any functional femur and acetabular aplasia. Prenatal diagnosis of PFFD is still a challenge, but early recognition of this malformation could provide useful information to both parents and physicians concerning management and therapeutic planning. For this review, we analyzed all the cases of prenatally diagnosed PFFD that were reported in the literature from 1990 to 2014 and provide a description of the most common prenatal sonographic findings

Beyond the knowledge level: Behavior descriptions of machine learning systems

For the last fifteen years the field of machine learning has flourished and a number of complex and powerful learning systems have been developed. Knowledge level descriptions of such systems may be most useful for keeping an overview of the practical applicability of these systems. However, Dietterich's (1986) knowledge level analysis yielded very disappointing results: Learning could be characterized as an increase of knowledge in only a small number of deductive learning systems (e.g. MRS as a deductive knowledge level learning system - DKLL). The other systems were either not describable at the knowledge level (non-deductive knowledge level learning - NKLL) or did not show any increase in knowledge during learning (symbol level learning - SLL). In order to overcome these problems we took Clancey's (1991) criticisms into account and extended Newell's knowledge level into behavior descriptions, where skills and performance are used as additional parameters for characterizing behavior..