Exploring the spatio-temporal impacts of farmland reforestation on ecological connectivity using circuit theory:A case study in the agro-pastoral ecotone of North China

Farmland reforestation can contribute substantially to ecological restoration.Previous studies have extensively examined the ecological effects of farmland reforestation,but few of them have investigated the spatiotemporal responses of broad-scale landscape connectivity to reforestation.By using a typical agro-pastoral ecotone in northern China as a case study,we addressed this issue based on an innovative integration of circuit theory approach and counterfactual analysis.The forest connectivity through multiple dispersal pathways was measured using the circuit theory approach,and its spatiotemporal changes after reforestation were evaluated by counterfactual analysis.The results showed that from 2000–2015,the reforested farmland occupied 2095 km^2,and 12.5% was on steeply sloped land.Farmland reforestation caused a greater increase in ecological connectivity by adding new ecological corridors and stepping stones in scattered forest areas rather than in areas with dense forest distributions.The newly added corridors and stepping stones were fragmented,short and narrow and thus deserve powerful protection.Future reforestation to improve landscape connectivity should highlight pinch point protection and obstacle removal as well as the tradeoff between farmland loss and farmer survival.Our findings are expected to inform the optimization of the Grain for Green policy from the perspective of broad-scale biodiversity conservation.

Impacts of multi-scenario land use change on ecosystem services and ecological security pattern: A case study of the Yellow River Delta

The Yellow River Delta(YRD), a critical economic zone along China's eastern coast, also functions as a vital ecological reserve in the lower Yellow River. Amidst rapid industrialization and urbanization, the region has witnessed significant land use/cover changes(LUCC), impacting ecosystem services(ES) and ecological security patterns(ESP). Investigating LUCC's effects on ES and ESP in the YRD is crucial for ecological security and sustainable development. This study utilized the PLUS model to simulate 2030 land use scenarios, including natural development(NDS), economic development(EDS), and ecological protection scenarios(EPS). Subsequently, the InVEST model and circuit theory were applied to assess ES and ESP under varying LUCC scenarios from 2010 to 2030. Findings indicate:(1) Notable LUCC from 2010 to 2030, marked by decreasing cropland and increasing construction land and water bodies.(2) From 2010 to 2020, improvements were observed in carbon storage,water yield, soil retention, and habitat quality, whereas 2020–2030 saw increases in water yield and soil retention but declines in habitat quality and carbon storage. Among the scenarios, EPS showed superior performance in all four ES.(3) Between 2010 and 2030, ecological sources, corridors, and pinchpoints expanded, displaying significant spatial heterogeneity. The EPS scenario yielded the most substantial increases in ecological sources,corridors, and pinchpoints, totaling 582.89 km^(2), 645.03 km^(2),and 64.43 km^(2), respectively. This study highlights the importance of EPS, offering insightful scientific guidance for the YRD's sustainable development.

Analyzing multi-circular loop scatterers by Maxwellian circuits

Calculating the current distribution in circular loop scatterers commonly involves complicated computation. In this paper, based on the theory of Maxwellian circuits （MC）, we propose a fast algorithm by solving a wave equation with constant parameters corresponding to the circular loop. Our method prodeces similar results compared to the methods using method of moments （MoM） with lower computational complexity. It is effective when there are parallel multiple circular loop scatterers. Experimental results show accuracy of the method.

Habitat Suitability &Connectivity of Alborz Wild Sheep in the East of Tehran, Iran

Habitat loss and fragmentation of the wildlife species due to anthropogenic developments have been becoming serious issues in biological conservation. Alborz wild sheep, listed as threatened by IUCN, is distributed in relatively small and isolated patches in an increasingly human dominated landscape in the north-central Iran and east of Tehran. We used maximum entropy modeling to identify habitat areas of the wild sheep, across Jajrud protected area and its neighbouring protected areas including varjin, lar, koohsefid and the surroundings. Regarding to seasonal variation of the species home range, winter, summer and multi seasonal (annual) habitats were predicted. To estimate habitat connectivity, we used models of connectivity based in electrical circuit theory. Applying core areas of multi season for connectivity analysis, movement pattern of the species was predicted and important connective areas for conservation were identified. Species distribution maps revealed that the summer and winter habitats were approximately occurred in similar areas. Distance to eco-guards’ post was the most important predictor for both habitat models of summer and winter. The annual model, which is a combination of summer and winter, shows that the largest suitable habitat patches are located in the north, south and west of the study area. Maximum current flow map demonstrates that the areas among patch pairs are covered in low current, reflecting low rates of the species dispersal. This map presented bottlenecks to the species movement across major roads and along extending human settlements. Cumulative current flow map displayed that current was highest in Jajrud north of Mamloo extending to the northern Jajrud. Overall, our study demonstrated a prediction of habitat suitability and connectivity for Alborz wild sheep in east of Tehran, which can be used to direct conservation endeavours dealing with maintenance of the wild sheep metapopulation dynamics.

Construction of ecological security patterns and ecological restoration zones in the city of Ningbo,China

Studying an ecological restoration zoning process under the background of ecological security patterns is of great significance to the rapid adjustment and optimization of a landscape pattern.In this study,a remote sensing ecological index and a morphological spatial pattern analysis method were used to assess the quality of habitats and identify ecological sources in the city of Ningbo;ecological corridors,ecological pinch points,and ecological barrier points were extracted by using a circuit theory to construct ecological security patterns and ecological restoration zones.The results indicate:(1)There were 47 ecological sources,and 83 key ecological corridors in Ningbo,and the ecological land area was about 1898.39 km^(2),accounting for 19.89%of the total study area.(2)The ecological source areas were distributed in“one patch and three belts”,and the low-resistance ecological corridors were concentrated in southern Yuyao city,western Haishu district,and central and western Fenghua district;the ecological network in the western and southern regions was dense.(3)There were four types of ecological restoration zones that need to be established,which were prioritized restoration zones,prioritized protection zones,key conservation zones,and general conservation zones distributed hierarchically from inner part towards outside.(4)Ninghai county,Yuyao city,and Fenghua district had large ecological land areas,however,prioritized restoration and protection zones in Ninghai and Fenghua were also large.The analysis results are expected to provide a reference for optimizing a territorial ecological space in a city.

Optical E-field probe using LiNbO_3 M-Z waveguides in the electromagnetic compatibility measurements

An integrated optical E-field probe with the segmented electrode using LiNbO3 Mach-Zehnder （M-Z） waveguides is proposed and an equivalent circuit of the segmented electrode is given. According to the circuit theory, the electrode structure of the probe is designed. The unpackaged size of the fabricated probe is as small as 60× 6 × 0.5 （mm）. The measured results show that the half wavelength voltage is 7.7 V, the ±5 dB baseband range is 3 GHz, and the minimum detectable field is lower than 90 dB.μV/m （bandwidth 100 Hz）. Therefore it can be used in the electromagnetic compatibility （EMC） measurements. OCIS codes： 130.3120, 130.6010, 230.4110.

Identifying priority areas for conservation in the lower Yellow River basin from an ecological network perspective

Taking the lower Yellow River basin as the study area,this study aims to construct ecological networks to mitigate the negative impacts of rapid urbanization on the ecosystem.Ecological sources were identified based on morphological spatial pattern analysis(MSPA),habitat quality and landscape connectivity.The ecological resistance surface was constructed and corrected by integrating natural and anthropogenic factors.The spatial range of ecological corridors and some of their key nodes were identified based on circuit theory.The ecological network(EN)was finally optimized using a similarity search and cost connectivity modules.The results show that the optimized ecological network structure is more stable than before.The EN includes 23 ecological sources with a total area of 5464.8 km^(2)and 30 ecological corridor clusters with a total area of 2205.92 km^(2).Through the internal landscape heterogeneity of the corridor,28 ecological node areas and 75 barrier areas were identified as key protection and restoration areas,with a total area of 78.44 km^(2)and 372.79 km^(2),respectively.Through the construction and optimization of EN,this study identifies key areas for promoting ecological sustainability and provides a useful framework for coordinating regional ecological conservation and economic development.

New Results on the Resistance of n-Cube

The resistance seen into the port in an n-cube formed by two vertices of distance n-1 is exactly formulated for any positive integer n. The resistances seen into the port in an n-cube formed by any two vertices is also found by experiments for 1 n7.

Design of ternary low-power Domino JKL flip-flop and its application

By researching the ternary flip-tlop and the adiabatic Domino circuit,a novel design of low-power ternary Domino JKL flip-flop on the switch level is proposed.First,the switch-level structure of the ternary adiabatic Domino JKL flip-flop is derived according to the switch-signal theory and its truth table.Then the ternary loop operation circuit and ternary reverse loop operation circuit are achieved by employing the ternary JKL tlip-tlop. Finally,the circuit is simulated by using the Spice tool and the results show that the logic function is correct. The energy consumption of the ternary adiabatic Domino JKL flip-flop is 69%less than its conventional Domino counterpart.