The effect of diffusion on the time varying logistic population growth

AbstractIn this paper, we consider the effect of diffusion on the species that live in changing patches environment. Different from the former studies [1–4], we pay attention to the more important situation in conservation biology that species live in a weak patches environment, in the sense that species in some of the isolated patches will be extinct without the contribution from other patches. We obtain an interesting result: the identical species can persist for some diffusion rates, and can also vanish for another set of restriction on diffusion rates

Sulfur Speciation in the Surface Sediments of Lakes from Different Regions, China: Characterization by S K-Edge XANES Spectroscopy

X-ray absorption near edge structure (XANES) spectroscopy affords the opportunity to determine redox status for element S in the aquatic ecosystems. However, there have been relatively few studies of S XANES spectroscopy in the terrestrial aquatic ecosystems. In this study, XANES technology was used to examine changes in S speciation in the sediments collected from Taihu Lake, Qinghai Lake, Dianchi Lake, Caohai Lake, and Hongfeng Lake located in distinct geological background areas of China. The results showed that sedimentary S in Qinghai Lake has a high proportion of sulfate averaged 88.9% due to physical weathering of watershed rocks, while deposited S in Taihu Lake has a high fraction of intermediate S (36.5%), which may be the response of the agricultural nonpoint source pollution in drainage basin. The three lakes located in Southwest China have similar composition characteristics of S species, indicating similar S sources including chemical weathering of carbonate and atmospheric deposition. 60–90% of S compounds in the surface sediments were in the form of sulfate and FeS. In deeper layers, the ratio of FeS2 and the intermediate S significantly increased, suggesting rapid processes of sulfate reduction and sulfide reoxidation with the increasing depths

Differences in perceptual representations in multilinguals’ first, second, and third language

Two experiments were conducted to investigate the differences in perceptual representations among multilingual individuals. In Experiment 1, the immediate sentence-picture verification paradigm was used to investigate perceptual representations in the working memory stage. The results suggest a match effect within the first language (Cantonese), but not within the second language (Mandarin) or the third language (English), showing perceptual representations only in first language comprehension. In Experiment 2, the delayed sentence-picture verification paradigm was used to investigate perceptual representations in long-term memory. Similarly, the results suggest a match effect within the first language (Mandarin), but not within the second language (English). The findings of both experiments suggest that the first language was perceptually represented, regardless of whether it was Cantonese or Mandarin, regardless of the processing in working memory or long-term memory. No evidence was found for perceptual representations in the later-learned languages, regardless of high or low proficiency. Our study has implications for theories of language comprehension and embodied cognition

A systematic review of maggot debridement therapy for chronically infected wounds and ulcers

SummaryObjectiveThis study aimed to systematically evaluate maggot debridement therapy (MDT) in the treatment of chronically infected wounds and ulcers.MethodsWe performed a meta-analysis referring to the PRISMA statement (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). We searched for published articles in the following databases: PubMed, Web of Science, Embase, Wanfang (Chinese), and the China National Knowledge Infrastructure (CNKI). The latest search was updated on March 14, 2014. For dichotomous outcomes, the effects of MDT were expressed as the relative risk (RR) and 95% confidence interval (CI). For continuous outcomes with different measurement scales, we calculated the standardized mean difference (SMD). The pooled effects were estimated using a fixed effect model or random effect model based on the heterogeneity test. Subgroup analyses were performed according to the types of wounds or ulcers.ResultsMDT had a significantly increased positive effect on wound healing compared with conventional therapies, with a pooled RR of 1.80 (95% CI 1.24–2.60). The subgroup analysis revealed that the combined RRs were 1.79 (95% CI 0.95–3.38) for patients with diabetic foot ulcers (DFU) and 1.70 (95% CI 1.28–2.27) for patients with other types of ulcers. The time to healing of the ulcers was significantly shorter among patients treated with MDT, with a pooled SMD of −0.95 (95% CI −1.24, −0.65). For patients with DFU, the SMD was −0.79 (95% CI −1.18, −0.41), and for patients with other types of ulcers, the SMD was −1.16 (95% CI −1.63, −0.69).ConclusionMDT not only shortened the healing time but also improved the healing rate of chronic ulcers. Therefore, MDT may be a feasible alternative in the treatment of chronic ulcers

Exclusive Enteral Nutrition versus Infliximab in Inducing Therapy of Pediatric Crohn’s Disease

Aim. To compare the effectiveness of exclusive enteral nutrition (EEN) and infliximab (IFX) therapy in pediatric Crohn’s disease (CD). Methods. In a prospective study of children initiating EEN or infliximab therapy for CD, we compared clinical outcomes using the pediatric Crohn’s disease activity index (PCDAI), growth improvement, endoscopic mucosal healing, and adverse effects. Data were measured at baseline and after 8 weeks of therapy. Results. We enrolled 26 children with CD; of whom, 13 were treated with infliximab, 13 with EEN. Clinical response (PCDAI) reduction ≥ 15 or final PCDAI ≤ 10 was achieved by 83.3% in the EEN group and 90.9% in the IFX group. Body mass index for age (BMIFA) z-scores were significantly increased in both groups (P<0.05). No significant differences were observed in PCDAI, height for age (HFA), or BMI recovery between two groups. Adverse effects were detected in 30.7% on infliximab and 0% on EEN. Mucosal healing was achieved in 71.4% cases in the EEN group versus 85.7% in the IFX group. Conclusion. EEN provided similar improvements as IFX in clinical symptoms, mucosal healing, and BMI. EEN therapy has less adverse effects when compared with IFX. This trial is registered with the Clinical Registration Number: ChiCTR-OON-17010834

Nonlinear Nanophotonic Devices in the Ultraviolet to Visible Wavelength Range

Although the first lasers invented operated in the visible, the first on-chip devices were optimized for near-infrared (IR) performance driven by demand in telecommunications. However, as the applications of integrated photonics has broadened, the wavelength demand has as well, and we are now returning to the visible (Vis) and pushing into the ultraviolet (UV). This shift has required innovations in device design and in materials as well as leveraging nonlinear behavior to reach these wavelengths. This review discusses the key nonlinear phenomena that can be used as well as presents several emerging material systems and devices that have reached the UV–Vis wavelength range

Nonlinear nanophotonic devices in the Ultraviolet to Visible wavelength range

Although the first lasers invented operated in the visible, the first on-chip devices were optimized for near-infrared (IR) performance driven by demand in telecommunications. However, as the applications of integrated photonics has broadened, the wavelength demand has as well, and we are now returning to the visible (Vis) and pushing into the ultraviolet (UV). This shift has required innovations in device design and in materials as well as leveraging nonlinear behavior to reach these wavelengths. This review discusses the key nonlinear phenomena that can be used as well as presents several emerging material systems and devices that have reached the UV-Vis wavelength range.Comment: 58 pages, 10 figure