The objective of this pal)er is to [brmalize the intuition al)out l,he comph;xity of syntactic structures. We propose a definition of structm:al COml)h'xity such that sentences ranked by our definition as more COml)h;x are gen(;rally more diI'ficult lbr humans to process. We justify the definition by showing how it is ahle to account for several seemingly unrelated phenomena in natural languages.

background: the ductus arteriosus connects the main pulmonary trunk to the descending aorta. the incidence of isolated patent ductus arteriosus (pda) in full-term infants is about 1 in 2000. the amplatzer ductal occluder (ado) is recommended for pdas with sizes larger than 2 mm. in this procedure, we must confirm the ado position in pda by aortogram from the arterial line. the purpose of this s...

background the ala of the nose, with its particular texture and characteristics, poses both aesthetically and functionally intriguing challenges and is rather problematic regarding choices for reconstructive methods. both flaps and grafts have been used to restore natural structure of nasal ala. the present study summarizes a ten-year experience of reconstructive surgery using small composite g...

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we consider the class of polynomial differential equation x&= , 2(,)(,)(,)nnmnmpxypxypxy++++2(,)(,)(,)nnmnmyqxyqxyqxy++&=++. for where and are homogeneous polynomials of degree i. inside this class of polynomial differential equation we consider a subclass of darboux integrable systems. moreover, under additional conditions we proved such darboux integrable systems can have at most 1 limit cycle.

chest tube (ct) or tube thoracostomy placement is often indicated following traumatic injuries. premature movement of the chest tube leads to increased hospital complications and costs for patients. placement of a chest tube is indicated in drainage of blood, bile, pus, drain air, and other fluids. although there is a general agreement for the placement of a chest tube, there is little consensu...