Dynamic Interrelation of Births and Deaths: Evidence from Plant Level Data

In this paper, the dynamic panel data method is used to investigate the dynamic interrelation of plant births and plant deaths. The dynamic panel data method considers the endogenous problem and individual effects. Empirical findings support the multiplier effect. In addition, exit does not cause entry, whereas entry causes exit.

Learning noise-induced transitions by multi-scaling reservoir computing

Noise is usually regarded as adversarial to extract the effective dynamics from time series, such that the conventional data-driven approaches usually aim at learning the dynamics by mitigating the noisy effect. However, noise can have a functional role of driving transitions between stable states underlying many natural and engineered stochastic dynamics. To capture such stochastic transitions from data, we find that leveraging a machine learning model, reservoir computing as a type of recurrent neural network, can learn noise-induced transitions. We develop a concise training protocol for tuning hyperparameters, with a focus on a pivotal hyperparameter controlling the time scale of the reservoir dynamics. The trained model generates accurate statistics of transition time and the number of transitions. The approach is applicable to a wide class of systems, including a bistable system under a double-well potential, with either white noise or colored noise. It is also aware of the asymmetry of the double-well potential, the rotational dynamics caused by non-detailed balance, and transitions in multi-stable systems. For the experimental data of protein folding, it learns the transition time between folded states, providing a possibility of predicting transition statistics from a small dataset. The results demonstrate the capability of machine-learning methods in capturing noise-induced phenomena

Eigenvalue problem for p-Laplacian three-point boundary value problems on time scales

AbstractLet T be a time scale such that 0,T∈T, β,γ⩾0 and 0<η<ρ(T). We consider the following p-Laplacian three-point boundary problem on time scales(φp(uΔ(t)))∇+λh(t)f(u(t))=0,t∈(0,T),u(0)−βuΔ(0)=γuΔ(η),uΔ(T)=0, where p>1, λ>0, h∈Cld((0,T),[0,∞)) and f∈C([0,∞),(0,∞)). Some sufficient conditions for the nonexistence and existence of at least one or two positive solutions for the boundary value problem are established. In doing so the usual restriction that f0=limu→0+f(u)φp(u) and f∞=limu→∞f(u)φp(u) exist is removed. An example is also given to illustrate the main results

Coordinated voltage regulation of hybrid AC/DC medium voltage distribution networks

Abstract In a hybrid AC/DC medium voltage distribution network, distributed generations (DGs), energy storage systems (ESSs), and the voltage source converters (VSCs) between AC and DC lines, have the ability to regulate node voltages in real-time. However, the voltage regulation abilities of above devices are limited by their ratings. And the voltage regulation efficiencies of these devices are also different. Besides, due to high r/x ratio, node voltages are influenced by both real and reactive power. In order to achieve the coordinated voltage regulation in a hybrid AC/DC distribution network, a priority-based real-time control strategy is proposed based on the voltage control effect of real and reactive power adjustment. The equivalence of real and reactive power adjustment on voltage control is considered in control area partition optimization, in which regulation efficiency and capability are taken as objectives. In order to accommodate more DGs, the coordination of controllable devices is achieved according to voltage sensitivities. Simulations studies are performed to verify the proposed method

Badanie wstępne ekspresji i wartości klinicznej oznaczenia czynnika wzrostu pochodzenia płytkowego BB, czynnika indukowanego hipoksją-1α i receptora chemokiny C-C typu 2 we krwi obwodowej w patogenezie choroby Gravesa-Basedowa

Introduction: Platelet-derived growth factor BB (PDGF-BB) plays an important role in the development of GD (Graves’ disease). However, it is still unknown whether PDGF-BB is expressed in peripheral blood and whether the expression of PDGF-BB contributes to GD. We aim to study the expression of PDGF-BB, hypoxia inducible factor (HIF)-1α and C-C motif chemokine receptor (CCR)-2 in peripheral blood of patients with GD and explore its effect and potential mechanism in pathogenesis. Material and methods: 41 patients with GD (GD group) and forty-five healthy people (control group) were chosen. The concentration of PDGF-BB and HIF-1α in peripheral blood specimens were detected and compared between the two groups. The expression of CCR2 in macrophages in the peripheral blood specimens were examined using FCM (Flow Cytometry). Results: Both PDGF-BB and HIF-1α were expressed in human peripheral blood from the two groups. Compared with specimens from healthy people, there were statistically increased concentrations of PDGF-BB and HIF-1α in the GD group (P < 0.05). The proportion of CCR2-positive macrophages in peripheral blood in the GD group was significantly higher than that in the control group (P < 0.05). Conclusions: CCR2-positive macrophages may induce the expression of PDGF-BB through HIF-1α signal, and the high expression of PDGF-BB may be involved in the pathogenesis of GD.Wprowadzenie: Czynnik wzrostu pochodzenia płytkowego BB (platelet-derived growth factor BB, PDGF-BB) odgrywa ważną rolę w roz­woju choroby Gravesa-Basedowa (Graves’ disease, GD). Jednak wciąż nie wiadomo, czy PDGF-BB ulega ekspresji we krwi obwodowej i czy ekspresja PDGF-BB przyczynia się do GD. Badanie przeprowadzono w celu zbadania ekspresji PDGF-BB, czynnika indukowanego hipoksją-1α (hypoxia inducible factor-1α, HIF-1α) i receptora chemokiny C-C typu 2 (C-C motif chemokine receptor-2, CCR-2) we krwi obwo­dowej pacjentów z GD i zbadania wpływu tych cząsteczek i potencjalnego mechanizmu ich działania w patogenezie choroby. Materiał i metody: Do badania włączono 41 pacjentów z GD (grupa GD) i 45 osób zdrowych (grupa kontrolna). Stężenie PDGF-BB i HIF-1α w próbkach krwi obwodowej oznaczono i porównano między grupami. Do pomiaru ekspresji CCR2 w makrofagach krwi obwodowej zastosowano metodę cytometrii przepływowej (flow cytometry, FCM). Wyniki: W obu grupach badanych stwierdzono ekspresję PDGF-BB i HIF-1α we krwi obwodowej. W grupie GD odnotowano istotne statystycznie wyższe stężenia PDGF-BB i HIF-1α niż u osób zdrowych (p &lt; 0,05). Odsetek makrofagów CCR2-dodatnich we krwi obwo­dowej w grupie GD był istotnie wyższy niż w grupie kontrolnej (p &lt; 0,05). Wnioski: Makrofagi CCR2-dodatnie mogą indukować ekspresję PDGF-BB za pośrednictwem sygnału HIF-1α, a wysoka ekspresja PDGF­BB może odgrywać rolę w patogenezie GD

Sublethal and Killing Effects of Atmospheric-Pressure, Nonthermal Plasma on Eukaryotic Microalgae in Aqueous Media

In-depth studies on the interaction of nonthermal plasmas with microorganisms usually focus on bacteria; only little attention has been given to their effects on more complex eukaryotic cells. We report here nonthermal plasma\u27s effects on cell motility, viability staining, and morphology of eukaryotic microalgae, with three marine dinoflagellates and a marine diatom as major targets. The effects on motility and viability staining depended on the time of exposure to plasma and the species of microalgae. We observed a strong pH decrease in aqueous samples (marine and freshwater algal cultures, their culture media, and deionized water) after exposure to plasma, and hypothesized this decreased pH as the principal mechanism by which plasma exerts its deleterious effects on cells in aqueous media. The hypothesis was supported by results of experiments in which decreasing the pH of algal samples (effected by addition of acid) caused the same morphological damage (as determined with scanning-electron microscopy) as did exposure to plasma

Optimal configuration of hybrid AC/DC urban distribution networks for high penetration renewable energy

Existing AC medium-voltage distribution networks are facing challenges on handling increasing loads and renewable energy integrations. However, it is very difficult to build new distribution lines in urban areas. This study proposes a configuration method of hybrid AC/DC medium-voltage distribution networks, in which some existing AC lines are converted to DC operation. Existing topologies and dispatching scenarios are considered during configuration because the overall power flow can be rescheduled in the hybrid AC/DC distribution network. Therefore, transfer capacities of the lines are fully utilised, and more renewable energies are accommodated. A bi-level programming model is established embedding chance constraint programming to consider the intermittent output of renewable energy. In the upper level, a multiple objective optimal model is proposed in order to balance investments, power losses, and the maximum load level and renewable energy capacity. In the lower level, daily operations of the newly installed VSCs are optimised by a chance constraint programming. The influences of energy storage systems on the configuration are also analysed. Simulation studies are performed to verify the proposed method