Spreading speeds and traveling waves in some population models.

Virtually every ecosystem has been invaded by exotic organisms with potentially drastic consequences for the native fauna or flora. Studying the forms and rates of invading species has been an important topic in spatial ecology. We investigate two two-species competition models with Allee effects in the forms of reaction-diffusion equations and integro-difference equations. We discuss the spatial transitions from a mono-culture equilibrium to a coexistence equilibrium or a different mono-culture equilibrium in these models. We provide formulas for the spreading speeds based on the linear determinacy and show the results on the existence of traveling waves. We also study a two-sex stage-structured model. We carry out initial analysis for the spreading speed and conduct numerical simulations on the traveling waves and spreading speeds in the two-sex model

Safety and Efficacy of Thermal Ablation for Small Renal Masses in Solitary Kidney: Evidence from Meta-Analysis of Comparative Studies

<div><p>Objective</p><p>To evaluate comparative renal functional preservation, perioperative and oncologic outcomes, and complications of thermal ablation (TA) versus partial nephrectomy (PN) in management of Small renal masses (SRMs) in solitary kidney.</p><p>Methods and Findings</p><p>Medline, Embase, Web of Science and the Cochrane Library were systematically searched. A meta-analysis for comparative studies comparing TA with PN was performed. According to predefined inclusion criteria, seven datasets were identified from 8 observational studies including a total of 628 patients. Cumulated data showed the changes of creatinine (<i>p</i>=0.02) and estimated glomerular filtration rate (eGFR) (<i>p</i><0.0001) in TA arm were significantly less than these in PN arm. Significantly less new-set chronic kidney disease (CKD) was observed in TA group (<i>p</i>=0.04). In terms of postoperative dialysis rate, the difference favoring TA was also noted, though there is no statistical significance (<i>p</i>=0.09). With regard to perioperative outcomes, our data demonstrated that patients who underwent TA had significantly shorter operation time (<i>p</i>=0.002), less blood loss (<i>p</i><0.0001), shorter length of stay (<i>p</i><0.00001), and less transfusion rate (<i>p</i>=0.01) than those underwent PN. In addition, patients underwent TA suffered less intra- and postoperative complications (<i>p</i>=0.007, <i>p</i><0.00001; respectively). With regard to oncologic outcomes, disease-free survival (DFS) (<i>p</i><0.00001) and cancer-specific survival (CSS) (<i>p</i>=0.01) in the PN arm were significantly better than these of the TA arm. But, TA yielded a comparable overall survival to PN (<i>p</i>=0.40). Sensitivity analyses led to very similar results with overall results, and confirmed its stability.</p><p>Conclusions</p><p>Our analysis indicates that PN have advantage in controlling cancer recurrence. However, TA is associated with significantly better renal functional preservation and perioperative outcomes, and less complications without increasing overall death. Our data suggest that indication for TA may be extended to select younger, healthier patients who desire a much less invasive therapeutic option.</p></div

Forest plot and meta-analysis of renal functional outcomes: a) Increase of creatinine; b) Decrease of eGFR; c) Risk of new-set chronic kidney disease (CKD); d) Sensitivity analysis for risk of new-set CKD; e) Postoperative dialysis rate.

<p>IV = inverse variance method; M-H = Mantel-Haenszel method; CI = confidence interval.</p

Baseline characteristics of included studies.

<p>LOE = Level of evidence; C-C = case-control; P-C = prospective cohort; C-S = case-series; AT = ablation therapy; PN = partial nephrectomy; CA = cryoablation; LPN = laparoscopic partial nephrectomy; PRFA = percutaneous radiofrequency ablation; PAT = percutaneous ablative therapy; OPN = open partial nephrectomy; RFA = radiofrequency ablation; NA = not applicable; eGFR = estimated glomerular filtration rate (ml/min/1.73m2); CKD = chronic kidney disease; Ma/Be/Un = malignant/benigh/unknown.</p><p>* Etiology of solitary kidney; Co/At/Ma/Be means isolated kidney was caused by congenital, atrophic, malignancy or benign disease.</p><p>^† Mean or median.</p><p>^¶ Percent of patients with American society of anesthesiologists (ASA) score 3 or 4; in study by Haber et al, ASA score is showed as mean ± standard difference.</p><p>^§ Modified Newcastle-Ottawa scale.</p><p>Baseline characteristics of included studies.</p

Flow diagram of studies identified, included, and excluded.

<p>Flow diagram of studies identified, included, and excluded.</p