[Paratesticular sarcoma with synchronous renal carcinoma.].

Objetive: Primary undifferentiated pleomorphic sarcoma (UPS) of the testicular tunics is rare, and synchronism with other malignancies of the urinary tract is uncommon, and may complicate the staging and therapeutic approach. We report the case of a patient diagnosed with primary paratesticular UPS with synchronous Renal Carcinoma.

Methods: Patient presenting with intrascrotal tumor who underwent left radical orchiectomy.

Competing metabolic strategies in a multilevel selection model.

The evolutionary mechanisms of energy efficiency have been addressed. One important question is to understand how the optimized usage of energy can be selected in an evolutionary process, especially when the immediate advantage of gathering efficient individuals in an energetic context is not clear. We propose a model of two competing metabolic strategies differing in their resource usage, an efficient strain which converts resource into energy at high efficiency but displays a low rate of resource consumption, and an inefficient strain which consumes resource at a high rate but at low yield.

Coexistence of competing metabolic pathways in well-mixed populations.

Understanding why strains with different metabolic pathways that compete for a single limiting resource coexist is a challenging issue within a theoretical perspective. Previous investigations rely on mechanisms such as group or spatial structuring to achieve a stable coexistence between competing metabolic strategies. Nevertheless, coexistence has been experimentally reported even in situations where it cannot be attributed to spatial effects [Heredity 100, 471 (2008)HDTYAT0018-067X10.