“I extend my previous work on life history optimization when body mass is divided into reserves and structure components. Two important innovations are: (1) effect of finite target size on optimal structural growth; (2) incorporating reproduction in the optimization objective. I derive optimal growth trajectories and life histories, given that the individual is subject to both starvation mortality and exogenous hazards (e.g., predation). Because of
overhead costs in building structural mass, it is optimal to stop structural growth close to the target size, and to proceed only by accumulating reserves. Higher overhead costs cause earlier cessation of structural Volasertib research buy growth and smaller final structures. Semelparous
www.selleckchem.com/products/pf-477736.html reproduction also promotes early cessation of structural growth, compared to when only survival to target size is maximized. In contrast, iteroparous reproduction can prolong structural growth, resulting in larger final structures than in either the survival or the semelparous scenarios. Increasing the noise in individual growth lowers final structural mass at small target sizes, but the effect is reversed for large target sizes. My results provide predictions for comparative studies. I outline important consequences of my results to additional important evolutionary questions: evolution of sexual dimorphism, optimization of clutch size and evolution of progeny and adult sizes. (C) 2010 Elsevier Ltd. All rights reserved.”
“BACKGROUND: Embolization of spinal dural arteriovenous fistulae (SDVAFs) has emerged as an alternative to surgery. However, surgical disconnection is a simple and effective procedure.
OBJECTIVE: To review results and complications of surgical treatment of 154 consecutive SDAVFs.
METHODS: The records of 154 consecutive patients with SDAVFs were retrospectively reviewed.
RESULTS: There were 120 males and 34 females (male/female ratio 3.5:1, mean age 63.6 years). The SDAVFs were located at the thoracic level in 92 patients and at the lumbar and sacral spine levels in 45 and 15 patients, respectively. The most Trichostatin A purchase common presenting
symptoms were motor dysfunction (65 patients), sensory loss (31 patients), and paresthesias without sensory loss (13 patients). The mean interval from symptom onset to definitive diagnosis was 24.7 months (median 12 months). Surgery resulted in complete exclusion of the fistula at first attempt in 146 patients (95%). There were no deaths or major neurological complications related to the surgery. Six percent of patients experienced subjective or objective worsening of preoperative symptoms and signs by the time of discharge that persisted at follow-up. Other surgical complications consisted of wound infection in 2 patients and deep venous thrombosis in 3. Eight patients were lost to follow-up; 141 patients (96.6%) experienced improvement (120 patients, 82.2%) or stability (21 patients, 14.