Non-equilibrium dynamics in the form of oscillations or chaos is often found to be a natural phenomenon in complex ecological systems. In this paper, we first analyze a tri-trophic food chain, which is an extension of the Rosenzweig-MacArthur di-trophic food chain. We then explore the impact of harvesting individual trophic levels to answer the following questions : a) when a non-equilibrium dynamics persists, b) whether it can locally be stabilized to a steady state, c) when the system switches from a stable steady state to a non-equilibrium dynamics and d) whether the Maximum Sustainable Yield (MSY) always exists when the top predator is harvested. It is shown that searching for a general theory to unify the harvesting induced stability must take into account the number of trophic levels and the degree of species enrichment, the outcomes that cannot be obtained from the earlier reports on prey-predator models. We also identify the situation where harvesting induces instability switching: the non-equilibrium state enters into a stable steady-state and then, upon more intensive harvesting, the steady-state again loses its stability. One of the new and important results is also that the MSY may not exist for harvesting the top predator. In general, our results contribute to biological conservation theory, fishery and ecosystem biodiversity management.
Department of Oncology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Lung Cancer Institute, Jinan, China.
Background: Patients receiving chest radiation therapy, or exposed to high radiation levels due to accidental nuclear leakage are at risk of radiation-induced lung injury (RILI). In innate immunity, macrophages not only exhibit certain radiation tolerance but also play an important regulatory role in the whole pathological process. Nervonic acid (NA), a long-chain unsaturated fatty acid found in nerve tissue, plays a pivotal role in maintaining normal tissue growth and repair.
The clinical research findings on the effects of okra consumption on blood glucose and lipids are inconsistent. In this study, we aimed to explore the impact of okra consumption on glycemic parameters and lipid profile in adults, including homeostatic model assessment for insulin resistance (HOMA-IR), glycosylated hemoglobin A1c (HbA1c), fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). To find relevant randomized controlled trials (RCTs), we systemically searched EMBASE, Web of Science, PubMed, Cochrane Library, and Scopus until April 2024.
The objective of this investigation was to examine the effects of distinct dosages of infant formula and diverse formula constituents on the growth and development of weaned rats. Fifty specific pathogen-free (SPF) male Sprague-Dawley (SD) rats aged 3 weeks were divided into the basic diet group, 20% ordinary milk powder group, 20% special formula milk powder group, 30% ordinary milk powder group, and 30% special formula milk powder group randomly. After 28 days of feeding, compared with the basic diet group, the body mass and brain/body weight of rats in the 30% ordinary and special formula milk powder groups were decreased.
Hyperlipidemia is a malnutrition disease associated with different lifestyle factors mainly high fat/cholesterol foods consumption and less physical activity. Consumption of high fiber foods (prebiotic sources) additionally to gut microbiota (GM; probiotics species) could overcome hyperlipidemia and its associated risks. Prebiotics and probiotics are known by protective effects in different diseases like diabetes, inflammatory bowel diseases, and cardiovascular diseases.
