Perfect anomalous reflections have been demonstrated in optical phase gradient metasurfaces(PGMs),but they suffer from single-frequency(narrow-band)response due to the intrinsic limitation of natural geometric periodi...Perfect anomalous reflections have been demonstrated in optical phase gradient metasurfaces(PGMs),but they suffer from single-frequency(narrow-band)response due to the intrinsic limitation of natural geometric periodicity.Here,we provide both numerical and analytical evidence that a depth gradient metasurface can achieve discrete ultra-broadband perfect anomalous reflection in the microwave range in the absence of geometric periodicity.Remarkably,by adjusting the operating frequency of the incident wave,the same effect can be steadily obtained via a physically equivalent phase periodicity in the PGM.Based on this mechanism,a perfect retroreflector with a broadband response ranging from 1 GHz to 40 GHz is realized.Our work has promising applications in communication,source tracking,and military satellites.展开更多
We applied under pot-culture conditions and the double-casing pot method to study the characteristics of photosynthetic gas exchange and chlorophyll fluorescence in the leaves of Physocarpus amurensis Maxim （PA） and...We applied under pot-culture conditions and the double-casing pot method to study the characteristics of photosynthetic gas exchange and chlorophyll fluorescence in the leaves of Physocarpus amurensis Maxim （PA） and Physocarpus opulifolius under flooding stress. Our results indicate a significantly higher flooding tolerance of P. opulifolius compared to P. amurensis. Especially in P. amurensis, the limitation of non-stomatal factors played a major role in the advanced stages of flooding stress, observed as a rapid increase of the intercellular C02 con- centration （Ci） and a decrease of the stomatal limitation value （Ls）. The maximal PSII photochemical efficiencies （Fv/Fm） and actual photochemical efficiency （60PSU） in the leaves of P. opulifolius were extent of decrease during the than in P. amurensis. In significantly higher, and the flooding process was smaller addition, the non-chemical quenching （NPQ） in the leaves of P. opulifolius significandy increased from the 10th day under flooding stress, while the variation of NPQ in the leaves of P. amurensis was much smaller. This indicates that the leaves of P. opulifolius had not only higher PSII photochemical activity, but also improved tolerance to flooding stress, which may be caused by its ability to dissipate excess excitation energy by starting NPQ. At the 16th day under flooding stress, the PLABS significantly decreased with greater extent of decrease than Fv/Fm in the leaves of both Physocarpus, but the decreasing extent of PIABS in P. opulifolius was significantly smaller than in P. amurensis. In the 16th day under flooding stress, the fluorescence at J and I point （VJ and V1） in P. amurensis were significantly higher, and the extent of increase in VJ was greater than V1. However, the variations of VJ and V1 in the leaves of P. opulifolius were smaller, suggesting that the damage sites of flooding stress to PSII in the leaves of P. amurensis were mainly located in the electron transport process from QA at the PSII receptor side to QB- Flooding stress reduced the proportion （φEo） of luminous energy absorbed by the PSII reaction center for the electron transport following Q2, while the maximum quantum yield （φDo） of non-photochemical quenching increased. However, the TRo/RC and ETo/RC in the leaves of P. amurensis decreased accompanied by a dramatic increase of energy （DIo/RC） from the dissipation in the reaction center. This further indicated that the function of the PSII reaction center in the leaves of P. amurensis was significantly lower than in P. opulifolius.展开更多
Background:In the 21st century,as globalization accelerates and global public health crises occur,the One Health approach,guided by the holistic thinking of human-animal-environment and emphasizing interdisciplinary c...Background:In the 21st century,as globalization accelerates and global public health crises occur,the One Health approach,guided by the holistic thinking of human-animal-environment and emphasizing interdisciplinary collaboration to address global health issues,has been strongly advocated by the international community.An immediate requirement exists for the creation of an assessment tool to foster One Health initiatives on both global and national scales.Methods:Built upon extensive expert consultations and dialogues,this follow-up study enhances the 2022 global One Health index(GOHI)indicator system.The GOHI framework is enriched by covering three indices,e.g.external drivers index(EDI),intrinsic drivers index(IDI),and core drivers index(CDI).The comprehensive indicator system incorporates 13 key indicators,50 indicators,and 170 sub I-indicators,utilizing a fuzzy analytic hierarchy process to ascertain the weight for each indicator.Weighted and summed,the EDI,IDI,and CDI scores contribute to the computation of the overall GOHI 2022 score.By comparing the ranking and the overall scores among the seven regions and across 160 countries/territories,we have not only derived an overall profile of the GOHI 2022 scores,but also assessed the GOHI framework.We also compared rankings of indicators and sub Iindicators to provide greater clarity on the strengths and weaknesses of each region within the One Health domains.Results:The GOHI 2022 performance reveals significant disparities between countries/territories ranged from 39.03 to 70.61.The global average score of the GOHI 2022 is 54.82.The average score for EDI,IDI,and CDI are 46.57,58.01,and 57.25,respectively.In terms of global rankings,countries from North America,Europe and Central Asia,East Asia and Pacific present higher scores.In terms of One Health domains of CDI,the lowest scores are observed in antimicrobial resistance(median:43.09),followed by food security(median:53.78),governance(median:54.77),climate change(median:64.12)and zoonotic diseases(median:69.23).Globally,the scores of GOHI vary spatially,with the highest score in North America while lowest in sub-Saharan Africa.In addition,evidence shows associations between the socio-demographic profile of countries/territories and their GOHI performance in certain One Health scenarios.Conclusion:The objective of GOHI is to guide impactful strategies for enhancing capacity building in One Health.With advanced technology and an annually updated database,intensifying efforts to refine GOHI's data-mining methodologies become imperative.The goal is to offer profound insights into disparities and progressions in practical One Health implementation,particularly in anticipation of future pandemics.展开更多
With the popularity of smartphones,it is often easy to maliciously leak important information by taking pictures of the phone.Robust watermarking that can resist screen photography can achieve the protection of inform...With the popularity of smartphones,it is often easy to maliciously leak important information by taking pictures of the phone.Robust watermarking that can resist screen photography can achieve the protection of information.Since the screen photo process can cause some irreversible distortion,the currently available screen photo watermarks do not consider the image content well and the visual quality is not very high.Therefore,this paper proposes a new screen-photography robust watermark.In terms of embedding region selection,the intensity-based Scale-invariant feature transform(SIFT)algorithm used for the construction of feature regions based on the density of feature points,which can make it more focused on the key content of the image;in terms of embedding strength,the Just noticeable difference(JND)model is applied to limit the intensity of the watermark embedding according to the luminance and texture of the picture to balance robustness and invisibility;after embedding watermark,the coefficients in the neighborhood are again adjusted with optimal constraints to improve the accuracy of watermark extraction.After experiments,it is shown that the method we proposed can improve the correct rate of watermark extraction,the quality of the visual aspect of the watermarked picture is also improved.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12274313,62275184,and 62411540033)Collaborative Innovation Center of Suzhou Nano Science and Technology,Suzhou Basic Research Project(Grant No.SJC2023003)+1 种基金the Gusu Leading Talent Plan for Scientific and Technological Innovation and Entrepreneurship(Grant No.ZXL2024400)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Perfect anomalous reflections have been demonstrated in optical phase gradient metasurfaces(PGMs),but they suffer from single-frequency(narrow-band)response due to the intrinsic limitation of natural geometric periodicity.Here,we provide both numerical and analytical evidence that a depth gradient metasurface can achieve discrete ultra-broadband perfect anomalous reflection in the microwave range in the absence of geometric periodicity.Remarkably,by adjusting the operating frequency of the incident wave,the same effect can be steadily obtained via a physically equivalent phase periodicity in the PGM.Based on this mechanism,a perfect retroreflector with a broadband response ranging from 1 GHz to 40 GHz is realized.Our work has promising applications in communication,source tracking,and military satellites.
基金supported by the National Natural Science Foundation of China(No.31500323)
文摘We applied under pot-culture conditions and the double-casing pot method to study the characteristics of photosynthetic gas exchange and chlorophyll fluorescence in the leaves of Physocarpus amurensis Maxim （PA） and Physocarpus opulifolius under flooding stress. Our results indicate a significantly higher flooding tolerance of P. opulifolius compared to P. amurensis. Especially in P. amurensis, the limitation of non-stomatal factors played a major role in the advanced stages of flooding stress, observed as a rapid increase of the intercellular C02 con- centration （Ci） and a decrease of the stomatal limitation value （Ls）. The maximal PSII photochemical efficiencies （Fv/Fm） and actual photochemical efficiency （60PSU） in the leaves of P. opulifolius were extent of decrease during the than in P. amurensis. In significantly higher, and the flooding process was smaller addition, the non-chemical quenching （NPQ） in the leaves of P. opulifolius significandy increased from the 10th day under flooding stress, while the variation of NPQ in the leaves of P. amurensis was much smaller. This indicates that the leaves of P. opulifolius had not only higher PSII photochemical activity, but also improved tolerance to flooding stress, which may be caused by its ability to dissipate excess excitation energy by starting NPQ. At the 16th day under flooding stress, the PLABS significantly decreased with greater extent of decrease than Fv/Fm in the leaves of both Physocarpus, but the decreasing extent of PIABS in P. opulifolius was significantly smaller than in P. amurensis. In the 16th day under flooding stress, the fluorescence at J and I point （VJ and V1） in P. amurensis were significantly higher, and the extent of increase in VJ was greater than V1. However, the variations of VJ and V1 in the leaves of P. opulifolius were smaller, suggesting that the damage sites of flooding stress to PSII in the leaves of P. amurensis were mainly located in the electron transport process from QA at the PSII receptor side to QB- Flooding stress reduced the proportion （φEo） of luminous energy absorbed by the PSII reaction center for the electron transport following Q2, while the maximum quantum yield （φDo） of non-photochemical quenching increased. However, the TRo/RC and ETo/RC in the leaves of P. amurensis decreased accompanied by a dramatic increase of energy （DIo/RC） from the dissipation in the reaction center. This further indicated that the function of the PSII reaction center in the leaves of P. amurensis was significantly lower than in P. opulifolius.
基金supported by China Medical Board[No.20–365]Bill&Melinda Gates Foundation[No.INV-046218]the National Natural Science Foundation of China[No.72204160].
文摘Background:In the 21st century,as globalization accelerates and global public health crises occur,the One Health approach,guided by the holistic thinking of human-animal-environment and emphasizing interdisciplinary collaboration to address global health issues,has been strongly advocated by the international community.An immediate requirement exists for the creation of an assessment tool to foster One Health initiatives on both global and national scales.Methods:Built upon extensive expert consultations and dialogues,this follow-up study enhances the 2022 global One Health index(GOHI)indicator system.The GOHI framework is enriched by covering three indices,e.g.external drivers index(EDI),intrinsic drivers index(IDI),and core drivers index(CDI).The comprehensive indicator system incorporates 13 key indicators,50 indicators,and 170 sub I-indicators,utilizing a fuzzy analytic hierarchy process to ascertain the weight for each indicator.Weighted and summed,the EDI,IDI,and CDI scores contribute to the computation of the overall GOHI 2022 score.By comparing the ranking and the overall scores among the seven regions and across 160 countries/territories,we have not only derived an overall profile of the GOHI 2022 scores,but also assessed the GOHI framework.We also compared rankings of indicators and sub Iindicators to provide greater clarity on the strengths and weaknesses of each region within the One Health domains.Results:The GOHI 2022 performance reveals significant disparities between countries/territories ranged from 39.03 to 70.61.The global average score of the GOHI 2022 is 54.82.The average score for EDI,IDI,and CDI are 46.57,58.01,and 57.25,respectively.In terms of global rankings,countries from North America,Europe and Central Asia,East Asia and Pacific present higher scores.In terms of One Health domains of CDI,the lowest scores are observed in antimicrobial resistance(median:43.09),followed by food security(median:53.78),governance(median:54.77),climate change(median:64.12)and zoonotic diseases(median:69.23).Globally,the scores of GOHI vary spatially,with the highest score in North America while lowest in sub-Saharan Africa.In addition,evidence shows associations between the socio-demographic profile of countries/territories and their GOHI performance in certain One Health scenarios.Conclusion:The objective of GOHI is to guide impactful strategies for enhancing capacity building in One Health.With advanced technology and an annually updated database,intensifying efforts to refine GOHI's data-mining methodologies become imperative.The goal is to offer profound insights into disparities and progressions in practical One Health implementation,particularly in anticipation of future pandemics.
基金This work is supported by the National Key R&D Program of China under grant 2018YFB1003205by the National Natural Science Foundation of China under grant U1836208,U1836110+1 种基金by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)fundby the Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET)fund,China.
文摘With the popularity of smartphones,it is often easy to maliciously leak important information by taking pictures of the phone.Robust watermarking that can resist screen photography can achieve the protection of information.Since the screen photo process can cause some irreversible distortion,the currently available screen photo watermarks do not consider the image content well and the visual quality is not very high.Therefore,this paper proposes a new screen-photography robust watermark.In terms of embedding region selection,the intensity-based Scale-invariant feature transform(SIFT)algorithm used for the construction of feature regions based on the density of feature points,which can make it more focused on the key content of the image;in terms of embedding strength,the Just noticeable difference(JND)model is applied to limit the intensity of the watermark embedding according to the luminance and texture of the picture to balance robustness and invisibility;after embedding watermark,the coefficients in the neighborhood are again adjusted with optimal constraints to improve the accuracy of watermark extraction.After experiments,it is shown that the method we proposed can improve the correct rate of watermark extraction,the quality of the visual aspect of the watermarked picture is also improved.
