Carbon emission reduction potential assessment in food transportation by urban agriculture: A case study of main urban area of Nanjing, China.

As an emerging urban green infrastructure and continuous productive urban landscape, urban agriculture can increase the resilience of urban food systems and reduce carbon emission in food transportation. However, there are few studies in China on the potential of urban agriculture and its role in carbon emission reduction. With semantic segmentation and spatial analysis method to identify urban agricultural potential spaces on the ground and rooftops based on satellite images and Lidar point cloud data in the main urban area of Nanjing, we estimated their potential in vegetable production and the CO2 emission reduction effect in food transportation. The results showed that there were 2904.39 hm2 of ground and 2976.96 hm2 of rooftops in the study area with the potential to be used for urban agriculture. Under a scenario with 80% potential space utilization, it could produce approximately 225000 t of vegetables per year, which equated to 43.6% of annual vegetable consumption in the study area. Meanwhile, it would reduce CO2 emission in long distance food transportation by 63700 t per year.

Temporal and spatial patterns of habitat of Nipponia nippon in China under the background of climate change.

Crested ibis (Nipponia nippon) is one of the endangered species in the International Union for Conservation of Nature. It is of great significance to pay attention to the changes of its suitable habitat in the context of climate change. Based on the geographical distribution data of crested ibis, the MaxEnt model was used to predict the suitable habitat of crested ibis under current scenario and future climate change. The results showed that the prediction accuracy of MaxEnt model was high, with an AUC value of 0.989. The minimum temperature of the coldest month, the mean temperature of the coldest quarter, and the mean annual rainfall were the dominant environmental factors affecting the habitat of crested ibis. Under current climate scenario, the area of moderately and highly suitable area of Chinese crested ibis was 10.65×104 km2, mainly distributed in Shaanxi, Sichuan, Hubei, Henan, and Gansu. In the future, the suitable habitat area of crested ibis would increase significantly under climate change, mainly distributed in Anhui, Chongqing, Guizhou, Jiangsu, Hunan, Shandong, Shaanxi, Jiangxi, Taiwan, Yunnan, Liaoning, and Fujian. In the SSP126 scenario from 2041 to 2060, the suitable habitat area of crested ibis would reach the maximum, being 139.53×104 km2 higher than that of the current climate scenario, accounting for 19.6% of the land area. This study could provide a basis for policy making on the conservation of crested ibis under global climate change.

Construction and optimization of ecological networks based on future scenario simulation in Qianshan City, Anhui Province.

The rapid urbanization adversely affects landscape pattern of mountainous cities. It is of great practical significance to explore the spatial and temporal evolution of ecological networks in mountainous areas to achieve regional ecological security. Taking Qianshan City in Anhui Province as an example, based on the land use data in 2012 and 2020, we simulated the land use situation in 2036 with PLUS model, and constructed the ecological networks in 2020 and 2036, respectively. We further analyzed its spatial and temporal evolution characteristics and explored the optimization path of ecological network. The results showed that the scale of various land use types in Qianshan City would change little from 2020 to 2036. The construction land would be centered on the built-up area, expanding in a point and block shape to the surrounding area. The ecological space would be continuously squeezed and encroached. The overall complexity and connectivity of ecological networks in Qianshan City would increase. The number and area of ecological source sites would increase, expanding spatially to the southwest and northeast. The overall density and number of ecological corridors would increase, with a lack of ecological corridor connections in the east-west direction, which need urgent improvement. The stability of ecological networks could be improved through three major measures, including protection and restoration of source sites, optimization and cultivation of corridors, and zoning control.

[Using the environmental justice approach to evaluate equitable allocation of urban parks: A case study of main urban area of Nanjing, China]. / çŽ¯å¢ƒæ­£ä¹‰è§†è§’ä¸‹å ¬å›­ç»¿åœ°ç©ºé—´é ç½®å ¬å¹³æ€§è¯„ä»·­­ä»¥å—京市主城区为例.

Urban parks have broad benefits in promoting public health of urban residents and advancing urban sustainable development. The equity of urban park spatial allocation has a great significance for maintaining environmental justice. However, the current researches on the equity of urban park spatial allocation still focus on the quantity and geographical equality but pay less attention on the equity of quality and accessibility of spatial allocation. Based on the approach of environmental justice, with the main urban area of Nanjing as an example, we comprehensively analyzed the equity pattern of urban park spatial allocation from the three dimensions (six parameters), including park accessibility, area and quality. Integrated analysis methods were adopted, including internet map service for accessibility analysis, subjective and objective comprehensive quality evaluation, spatial autocorrelation and non-parametric test. The results showed that the spatial allocation pattern of urban parks in the study area had obvious core-edge characteristics. There was a certain degree of inequity in park accessibility, area and quality, with a relatively significant pattern of environmental injustice. There were significant differences in the inequity of six parameters in the three dimensions, with the accessibility score and accessible park area showing the most prominent inequity. The minimum time required to reach the park and the quality of the nearest urban park took the second place in inequity. The quantity of high-quality urban park and minimum time required to reach the high-quality urban park showed relatively small difference. The average values of accessibility score, total area and quality of urban parks accessible to high-income communities were 3.7, 2.7, and 1.6 times that of low-income communities, respectively. The results indicated that high-income communities enjoyed better accessibility, larger area and higher quality in terms of urban parks. Middle-income communities enjoyed the most prominent advantage of green space, while most low-income communities were unable to reach a high-quality urban park within 30 min's walk. Our results could provide a decision-making basis and planning reference for the optimal configuration and rational planning of urban parks in China.

Change of nutrients, microorganisms, and physical properties of exposed extensive green roof substrate.

Green roofs (GR) can be used as a nature-based solution to tackle eco-environmental problems caused by climate change and rapid urbanization. The substrate in the GRs is the growing medium for vegetation, and its properties directly affect the ecosystem services of GRs. To investigate the characteristic changes of an exposed substrate after the removal of vegetation, a one-year field experiment was conducted. Substrate properties were comprehensively compared for areas in GR that were planted with Sedum lineare and those with bare substrate. Results show that vegetation cover not only prevented substrate loss by 5.14% (p < 0.05) but also protected the chemical, microbial, and physical properties of the substrate. Moreover, the structure of the substrate changed, as evidenced by a significant increase in fine sand (p < 0.05). The results highlight that attention should be paid to maintaining vegetation cover during GR management. In addition, extensive GRs may not be suitable for fallowing. Once a GR has been established, it needs regular maintenance. Otherwise, the ecological and economic benefits of the GR may be reduced. The findings of the present study can be used to determine the life-cycle costs. Further research should focus on differences in the substrate loss rates, runoff, and temperatures of the substrates under exposure and vegetation cover. The microbial changes after revegetation should also be studied to clarify the role of vegetation in GR ecosystems. The present study provides a reference for improving GR management and ensuring their sustainability.

Photonic-dispersion neural networks for inverse scattering problems.

Inferring the properties of a scattering objective by analyzing the optical far-field responses within the framework of inverse problems is of great practical significance. However, it still faces major challenges when the parameter range is growing and involves inevitable experimental noises. Here, we propose a solving strategy containing robust neural-networks-based algorithms and informative photonic dispersions to overcome such challenges for a sort of inverse scattering problem-reconstructing grating profiles. Using two typical neural networks, forward-mapping type and inverse-mapping type, we reconstruct grating profiles whose geometric features span hundreds of nanometers with nanometric sensitivity and several seconds of time consumption. A forward-mapping neural network with a parameters-to-point architecture especially stands out in generating analytical photonic dispersions accurately, featured by sharp Fano-shaped spectra. Meanwhile, to implement the strategy experimentally, a Fourier-optics-based angle-resolved imaging spectroscopy with an all-fixed light path is developed to measure the dispersions by a single shot, acquiring adequate information. Our forward-mapping algorithm can enable real-time comparisons between robust predictions and experimental data with actual noises, showing an excellent linear correlation (R2 > 0.982) with the measurements of atomic force microscopy. Our work provides a new strategy for reconstructing grating profiles in inverse scattering problems.

Phase characterisation of metalenses.

Metalenses have emerged as a new optical element or system in recent years, showing superior performance and abundant applications. However, the phase distribution of a metalens has not been measured directly up to now, hindering further quantitative evaluation of its performance. We have developed an interferometric imaging phase measurement system to measure the phase distribution of a metalens by taking only one photo of the interference pattern. Based on the measured phase distribution, we analyse the negative chromatic aberration effect of monochromatic metalenses and propose a feature size of metalenses. Different sensitivities of the phase response to wavelength between the Pancharatnam-Berry phase-based metalens and propagation phase-reliant metalens are directly observed in the experiment. Furthermore, through phase distribution analysis, it is found that the distance between the measured metalens and the brightest spot of focusing will deviate from the focal length when the metalens has a low nominal numerical aperture, even though the metalens is ideal without any fabrication error. We also use the measured phase distribution to quantitatively characterise the imaging performance of the metalens. Our phase measurement system will help not only designers optimise the designs of metalenses but also fabricants distinguish defects to improve the fabrication process, which will pave the way for metalenses in industrial applications.

Coupling urban 3-D information and circuit theory to advance the development of urban ecological networks.

Ongoing, rapid urban growth accompanied by habitat fragmentation and loss challenges biodiversity conservation and leads to decreases in ecosystem services. Application of the concept of ecological networks in the preservation and restoration of connections among isolated patches of natural areas is a powerful conservation strategy. However, previous approaches often failed to objectively consider the impacts of complex 3-D city environments on ecological niches. We used airborne lidar-derived information on the 3-D structure of the built environment and vegetation and detailed land use and cover data to characterize habitat quality, niche diversity, and human disturbance and to predict habitat connectivity among 38 identified habitat core areas (HCAs) in Nanjing, China. We used circuit theory and Linkage Mapper to create a landscape resistance layer, simulate habitat connectivity, and identify and prioritize important corridors. We mapped 64 links by using current flow centrality to evaluate each HCA's contribution and the links that facilitate intact connectivity. Values were highest for HCA links located in the west, south, and northeast of the study area, where natural forests with complex 3-D structures predominate. Two smaller HCA areas had high centrality scores relative to their extents, which means they could act as important stepping stones in connectivity planning. The mapped pinch-point regions had narrow and fragile links among the HCAs, suggesting they require special protection. The barriers with the highest impact scores were mainly located at the HCA connections to Purple Mountain and, based on these high scores, are more likely to indicate important locations that can be restored to improve potential connections. Our novel framework allowed us to sufficiently convey spatially explicit information to identify targets for habitat restoration and potential pathways for species movement and dispersal. Such information is critical for assessing existing or potential habitats and corridors and developing strategic plans to balance habitat conservation and other land uses based on scientifically informed connectivity planning and implementation.

Acoplamiento de la Información Urbana en 3-D y la Teoría de Circuitos para Avanzar el Desarrollo de las Redes Ecológicas Urbanas Resumen El rápido crecimiento urbano en curso acompañado por la fragmentación y pérdida de hábitats obstaculizan la conservación de la biodiversidad y llevan a una disminución de los servicios ambientales. La aplicación del concepto de redes ecológicas en la preservación y restauración de las conexiones entre los fragmentos aislados de áreas naturales es una estrategia poderosa para la conservación. Sin embargo, las estrategias previas con frecuencia han fallado al no considerar de manera objetiva los impactos del ambiente complejo y tridimensional que tienen las ciudades sobre los nichos ecológicos. Usamos información derivada de lidar aéreos sobre la estructura tridimensional del ambiente construido y de la vegetación y detallamos la información sobre el uso y la cobertura del suelo para caracterizar la calidad del hábitat, la diversidad de nichos y la perturbación humana y así predecir la conectividad de hábitat entre 38 áreas nucleares de hábitat (ANHs) en Nanjing, China. Usamos la teoría de circuitos y el programa Linkage Mapper para crear una capa de resistencia de paisaje, simular la conectividad de hábitat e identificar y priorizar los corredores importantes. Mapeamos 64 conexiones mediante la centralidad del flujo de corriente para evaluar la contribución de cada ANH y las conexiones que facilitan la conectividad intacta. Los valores más altos fueron para las conexiones de ANH ubicadas en el oeste, sur y norte del área de estudio, en donde predominan los bosques naturales con estructuras tridimensionales complejas. Dos áreas más pequeñas de ANH tuvieron puntajes altos de centralidad en relación con sus extensiones, lo que significa que podrían fungir como pasos intermedios importantes en la planeación de la conectividad. Las regiones mapeadas de los puntos de fijación tuvieron conexiones estrechas y frágiles entre las ANHs, lo que sugiere que requieren de protección especial. Las barreras con los puntajes más elevados de impacto estuvieron localizadas principalmente en las conexiones entre las ANH y la Tierra de las Montañas Púrpuras. Con base en estos puntajes elevados hay mayor probabilidad de que indiquen localidades importantes que pueden ser restauradas para mejorar el potencial de las conexiones. Nuestro novedoso marco de trabajo nos permitió transmitir adecuadamente la información espacialmente explícita para identificar los objetivos de la restauración de hábitat y los caminos potenciales para el movimiento y la dispersión de las especies. Tal información es crítica para el análisis de los hábitats y corredores existentes o potenciales y para el desarrollo de planes estratégicos para equilibrar la conservación del hábitat y otros usos de suelo con base en la planeación e implementación de la conectividad científicamente informada.

Momentum-space imaging spectroscopy for the study of nanophotonic materials.

The novel phenomena in nanophotonic materials, such as the angle-dependent reflection and negative refraction effect, are closely related to the photonic dispersions E(p). E(p) describes the relation between energy E and momentum p of photonic eigenmodes, and essentially determines the optical properties of materials. As E(p) is defined in momentum space (k-space), the experimental method to detect the energy distribution, that is the spectrum, in a momentum-resolved manner is highly required. In this review, the momentum-space imaging spectroscopy (MSIS) system is presented, which can directly study the spectral information in momentum space. Using the MSIS system, the photonic dispersion can be captured in one shot with high energy and momentum resolution. From the experimental momentum-resolved spectrum data, other key features of photonic eigenmodes, such as quality factors and polarization states, can also be extracted through the post-processing algorithm based on the coupled mode theory. In addition, the interference configurations of the MSIS system enable the measurement of coherence properties and phase information of nanophotonic materials, which is important for the study of light-matter interaction and beam shaping with nanostructures. The MSIS system can give the comprehensive information of nanophotonic materials, and is greatly useful for the study of novel photonic phenomena and the development of nanophotonic technologies.

Determination of runoff response to variation in overland flow area by flow routes using UAV imagery.

Surface runoff can be routed to both pervious areas (PAs) and drainage systems during an overland flow. Excessive runoff from an impervious area (IA) flowing into a drainage system causes an overload, which can be relieved by diverting runoff to PAs. However, the hydrological link between IAs and PAs, especially the runoff response to variation in overland flow areas (OFAs), has not well been considered in runoff simulations due to the complexity of routing. To understand how the OFA within an IA contributes to runoff generation, a novel classification approach was applied to categorize the IA in a study area in Nanjing University, Xianlin campus, China into directly connected impervious area (DCIA) and indirectly connected impervious area (ICIA) by flow routes using high-resolution ground-based images (0.5 m) from an unmanned aerial vehicle. The OFAs then include DCIA and the total impervious area (TIA), which is the sum of DCIA and ICIA. The runoff simulations were supported by Storm Water Management Model (SWMM) calibrated with observed rainfall and runoff data. The resulting proportions of DCIA and ICIA of the study area were 34.13% and 10.99%, respectively. The spatial distributions of DCIA and ICIA are characterized by the subcatchment landscape heterogeneity resulting from vegetation, imperviousness, and slope. The observed runoff coefficients and peak flows were positively correlated with the percentages of DCIA and TIA. The runoff coefficient was significantly correlated with the DCIA in a light rainfall event of 18.4 mm (R2 =0.82) and with the TIA in a heavy rainfall event of 119 mm (R2 =0.92). Runoff generation is affected by both the characteristics of the rainfall event and the accompaning variations in OFAs. Results indicate that increasing of the flow connectivity from IAs to PAs and increasing the water retention capacity of PAs may be effective strategies for optimizing landscape patterns for stormwater management.

Cost-effectiveness Analysis of Green-Gray Stormwater Control Measures for Non-Point Source Pollution.

The control of non-point source pollution (NPS) is an essential target in urban stormwater control. Green stormwater control measures (SCMs) have remarkable efficiency for pollution control, but suffer from high maintenance，operation costs and poor performance in high-intensity rainfall events. Taking the Guilin Road subwatershed in Rizhao, China, as a case study, a scheme for coupling gray and green stormwater control measures is proposed, and the gray SCMs are introduced to compensate for the shortcomings of green SCMs. The System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN) model was employed to investigate the cost-effectiveness of three scenarios (green SCMs only, gray SCMs only, and coupled green-gray SCMs). The results show that the optimal solutions for the three scenarios cost USD 1.23, 0.79, and 0.80 million, respectively. The NPS control ability of the coupled green-gray scenario is found to be better than that of the other two scenarios under rainfall events above moderate rain. This study demonstrates that coupled green-gray stormwater control management can not only effectively control costs, but can also provide better pollution control in high-intensity rainfall events, making it an optimal scheme for effective prevention and control of urban non-point source pollution.

Investigation of extensive green roof outdoor spatio-temporal thermal performance during summer in a subtropical monsoon climate.

The thermal performance of green roofs is usually site-specific and changes temporally. Hence, thermal performance evaluation is necessary to optimize green roof design and its cooling effect. In this paper, we evaluated the outdoor spatio-temporal performance of a full-scale extensive green roof (EGR) in Nanjing, China throughout a summer at three heights (30, 60and 120cm). We found the EGR exhibited an overall slight diurnal cooling effect at all three heights (-0.09, -0.23, and - 0.09 °C, respectively), but there was an obvious warming effect at a couple of specific hours during daytime. Especially on sunny days, the maximum warming effect at all three heights was 1.59, 0.59, and 0.38 °C, respectively. During the night, the EGR had a pronounced cooling effect of -0.63, -0.40, and - 0.15 °C, respectively. Among the weather scenarios, sunny days had the highest impact on the EGR's thermal performance, while effects were less pronounced on cloudy and rainy days. The average range of hourly air temperature difference at 30 cm between EGR and a bare roof on selected days was 4.02 (sunny), 2.67 (cloudy), and 0.74 °C (rainy). The results of multiple-regression analyses showed strong and significant correlations of air temperature difference between the EGR and a bare roof with differences in relative humidity, net radiation, several measures of soil and surface temperature, and soil moisture as well as average solar radiation, air temperature and wind speed. The results implied that both the components of the EGR, such as green vegetation and the soil substrate layer, and the microclimate created by the EGR can feed back and contribute to the thermal performance of an EGR. Through this full-scale EGR research in a subtropical monsoon climate, we provide the scientific basis and actionable practices for green roof planning and design to alleviate the urban heat island effect towards designing climate-resilient cities.

[Effects of a Green Roof on Stormwater Regulation and Cost-benefit Analysis].

Increasingly frequent urban waterlogging disasters, which are mainly caused by the increase in impervious surfaces due to rapid urbanization, have attracted public attention. Green roofs are conducive to increasing the urban pervious surface area to control sources of runoff, which has great significance for the ecological environment. This study uses the green roof of the administrative building of Jinling Primary School in Nanjing as the study area. 76 rainfall-runoff events collected over 17 months (2016-06-2017-10) were used to calculate the comprehensive runoff control ability and factors influencing the green roof in the context of the site scale. Based on life cycle assessment theory, the benefits of stormwater regulation over its 30-year life cycle were quantitatively evaluated. The results show that:① The average retention of the green roof was 62.7%, which could have a significant impact on runoff and peak flow, reducing the runoff time and delaying the flood peak. ② The green roof has a strong ability to retain runoff during small and medium rainfall; however, this ability becomes low when the retention capacity is saturated or not fully recovered, even in small rainfall-runoff events. ③ The main factors affecting the retention ability of the green roof are the total rainfall, rainfall intensity, and water content of the growth substrate soil. ④ The green roof has great economic benefits, with a construction cost of about 12.51 yuan·m-3 and a return on investment of 0.41. The results of this study can provide an important scientific basis and decision-making reference for the planning and construction of green roofs and the promotion of related policies.

Evaluation of ultrasonography on carotid arteries and left ventricular function in patients with subclinical atherosclerosis.

Ultrasonography in the evaluation and diagnosis of carotid arteries and left ventricular function in patients with subclinical atherosclerosis (SA) was explored. In total, 152 patients with no obvious clinical symptoms of atherosclerosis confirmed by carotid ultrasonography in Tengzhou Central People's Hospital from September 2015 to March 2016 were enrolled as the experimental group, and further 45 patients with normal physical examination at the same time were collected as the control group. Patients in the experimental group were divided into three groups according to Framingham risk assessment: low, middle and high risk. The carotid arteries and left ventricular function of all patients were detected by Doppler ultrasound. There were differences in the systolic pressure, TG and TC between the control group and the experimental group (P<0.05). The expression levels of ß, cIMT, Ep and PWVß increased with the risk degree in the low, middle and high risk groups (P<0.05). The expression levels of LVEDV, LVESV, and LVEF in the experimental group were significantly decreased compared with those in the control group (P<0.05), while the expression levels of LAV, E/e, GLS and GCS were significantly increased compared with those in the control group (P<0.05). There was a difference of left ventricular function parameters in the low, medium and high risk groups (P<0.05). The expression levels of LVEDV, LVESV, LAV and E/e increased with the risk degree in the low, middle and high risk groups (P<0.05). The detection rate of plaque was lower in the low risk group than those in the middle and high risk group (P<0.05). By observing the parameters of carotid arteries and left ventricular function, it was found that ultrasonography has important clinical value in the early diagnosis of SA, and can be promoted in clinic.

Redescription of a Hymenostome Ciliate, Tetrahymena setosa (Protozoa, Ciliophora) Notes on its Molecular Phylogeny.

In recent years, Tetrahymena species have been used as model organisms for research in a wide range of fields, highlighting the need for a fuller understanding of the taxonomy of this group. It is in this context that this paper uses living observation and silver staining methods to investigate the morphology and infraciliature of one Tetrahymena species, T. setosa (Schewiakoff 1892 Verh. Naturh. Med. Ver. Heidelb., 4:544) McCoy (1975) Acta Protozool., 14:253; the senior subjective synonym of T. setifera Holz and Corliss (1956) J. Protozool., 3:112; isolated from a freshwater pond in Harbin, north-eastern China. This organism can be distinguished from other described Tetrahymena species mainly by its single caudal cilium, which is about twice the length of the somatic ciliature. While the Harbin isolate appears similar to the population described by Holz and Corliss (1956) J. Protozool., 3:112, an improved diagnosis for T. setosa is given based on the previous descriptions and the Harbin population. In summary, this species can be recognized mainly by the combination of the following characters: body in vivo approximately 40 µm × 25 µm, 21-26 somatic kineties, one to four contractile vacuole pores associated with meridians 6-11 and a single caudal cilium. The small subunit ribosomal (SSU) rRNA gene and the cox1 gene sequences of Harbin population are also characterized in order to corroborate that the isolated species branches in phylogenetic trees as a T. setosa species. The phylogenetic analysis also indicated that sequences of populations of Tetrahymena species should be published with detailed morphological identifications.

A chalcohalide glass/alloy based Ag+ ion - selective electrode with nanomolar detection limit.

In this paper, a silver ion-selective electrode material with lower detection limit is presented. The electrode is based on 22.5As2S3-22.5Ag2S-55AgCl chalcohalide glass membranes. The low detection limit decreases from the micromolar range of the original Ag2S-As2S3 electrode to the nanomolar level (1.89 nM) by introducing AgCl. The addition of AgCl increases the conductivity of the glasses and improves the analytical properties of electrodes because of the joint effects of Ag+ and Cl- on network structure of the glass. The super-Nernstian response behavior was observed for the partially crystallized electrode. The electrode containing AgCl also possesses a high selectivity (except for Hg2+), fast response and good stability.

[Land use change and its effects on ecosystem services value in Ji' nan City of Shandong Province, East China].

Based on the GIS software platform, referring to the China 'Terrestrial ecosystem services per unit area value', and by using transition matrix, Costanza evaluation formula, and sensitivity analysis, this paper studied the change characteristics of land use and ecosystem services value in Ji' nan City in 1989-2009. During the study period, the built-up area in the City increased by 99.65 km2, while agriculture land and green space reduced by 103.21 km2, 90.4% of which was taken by the built-up land. The total ecosystem services value decreased from 256.22 x 10(6) yento 214.16 x 10(6) yen, with a decrement of 42.06 x 10(6) yen, mainly due to the decrease in the areas of agriculture land and green space. For the sustainable development of the population, resources, and environment in Ji'nan City, future urban planning should pay more attention on the natural resources protection, reasonable planning of land use structure, and maintenance of ecosystem stability and balance.

[Suitability assessment of construction land in the central and southern parts of Hebei Province, China based on potential-limitation model].

The suitability assessment of regional construction land is one of the important prerequisites for the spatial arrangement in regional planning, and also, the important foundation for the reasonable utilization of regional land resources. With the support of GIS, and by using the regional comprehensive strength and spatial accessibility analysis and the eco-environmental sensitivity analysis, this paper quantitatively analyzed the development potential and its ecological limitation of the central and southern parts of Hebei Province. Besides, based on the cost-benefit analysis, the potential-limitation model was accordingly developed, and the three land suitability scenarios under different developmental concepts were captured through the interaction matrix. The results indicated that both the comprehensive strength and the development potential of the study area showed a primacy distribution pattern, and presented an obvious pole-axis spatial pattern. The areas with higher eco-environmental sensitivity were mainly distributed in the west regions, while those with lower eco-environmental sensitivity were in the east regions. Regional economic development concept had important effects on the regional ecological security pattern and urban growth. The newly developed principles and methods for the land suitability assessment in this paper could not only scientifically realize the spatial grid of regional development potential and capture the future land development trend and spatial distribution, but also provide scientific basis and effective ways for urban and regional planning to realize region 'smart growth' and 'smart conservation'.

Amorphous diamond-structured photonic crystal in the feather barbs of the scarlet macaw.

Noniridescent coloration by the spongy keratin in parrot feather barbs has fascinated scientists. Nonetheless, its ultimate origin remains as yet unanswered, and a quantitative structural and optical description is still lacking. Here we report on structural and optical characterizations and numerical simulations of the blue feather barbs of the scarlet macaw. We found that the sponge in the feather barbs is an amorphous diamond-structured photonic crystal with only short-range order. It possesses an isotropic photonic pseudogap that is ultimately responsible for the brilliant noniridescent coloration. We further unravel an ingenious structural optimization for attaining maximum coloration apparently resulting from natural evolution. Upon increasing the material refractive index above the level provided by nature, there is an interesting transition from a photonic pseudogap to a complete bandgap.