This study explores the impact of intergenerational differences on farmers' terrace abandonment in response to increasing intergenerational differentiation among rural households and the practical issue of terrace...This study explores the impact of intergenerational differences on farmers' terrace abandonment in response to increasing intergenerational differentiation among rural households and the practical issue of terrace abandonment. Logit and Tobit models are employed to conduct empirical analysis and it is found that terrace abandonment increases sequentially among the new, middle, and old generations, confirming that intergenerational differences significantly influence whether farmers abandon terraces and the terrace abandonment scale. Village characteristics and government subsidies significantly influence farmers' terrace abandonment. An increase in the number of migrant workers in the village increases terrace abandonment among new and middle generation farmers, whereas an increase in the distance from the village to the county significantly increases terrace abandonment among old generation farmers. An increase in the village's total population significantly reduces terrace abandonment among new generation farmers. An increase in government subsidies significantly reduces terrace abandonment among middle and old generation farmers. The impact of intergenerational differences on terrace abandonment is more pronounced in low-altitude areas. To reduce terrace abandonment, it is necessary to promote terrace transfer, develop characteristic agriculture, improve terrace farming subsidies, and propose targeted strategies for the different generations of farmers.展开更多
良性前列腺增生(benign prostatic hyperplasia,BPH)是引起中老年男性下尿路症状的常见原因,经尿道前列腺电切术(transurethral resection of the prostate,TURP)是泌尿外科治疗BPH的“金标准”^([1])。TURP对于前列腺体积较小的BPH患...良性前列腺增生(benign prostatic hyperplasia,BPH)是引起中老年男性下尿路症状的常见原因,经尿道前列腺电切术(transurethral resection of the prostate,TURP)是泌尿外科治疗BPH的“金标准”^([1])。TURP对于前列腺体积较小的BPH患者疗效确切,但用于治疗前列腺体积>80 mL的BPH患者时,术中出血量明显增加,术后下尿路症状改善不明显,且术后持续膀胱冲洗时间以及导尿管留置时间延长^([2-3])。美国泌尿外科协会指南指出,钬激光或铥激光前列腺剜除术是目前大体积前列腺增生和小体积前列腺增生患者均适用的微创治疗方法^([4])。展开更多
物联网和区块链等技术的兴起和发展,使得多方协同签名协议重新受到了关注.多方协同签名是一种特殊的数字签名,要求多个用户进行交互后共同对一个消息产生合法的签名,以达到认证的目的.优点在于相比起每个用户分别进行签名可以缩短尺寸,...物联网和区块链等技术的兴起和发展,使得多方协同签名协议重新受到了关注.多方协同签名是一种特殊的数字签名,要求多个用户进行交互后共同对一个消息产生合法的签名,以达到认证的目的.优点在于相比起每个用户分别进行签名可以缩短尺寸,同时使用分布式的方法,任何一方都无法独自进行签名,防范了因为单个用户的密钥丢失或被劫持而导致被冒充身份的隐患.另一方面,量子计算机的进展对传统的公钥密码方案构成了潜在的威胁,美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)在2016年启动抗量子密码(post-quantum cryptography,PQC)的国际标准征集项目,并于2022年7月确定了被选为标准的算法.同时,基于其入选的数字签名方案(例如CRYSTALS-Dilithium)的协同签名方案也已经陆续出现.2019年,中国密码学会举办了全国密码算法设计竞赛,其中公钥组获得一等奖的Aigis-sig签名方案采用了与Dilithium类似的结构.基于Aigis-sig数字签名方案设计了一种两方协同签名方案,称之为Aitps,并根据其提供的参数进行了实例化和对比,得到了相比已有的所有基于Dilithium的两方协同签名方案更优的密钥和签名大小,例如在同等的安全强度下签名尺寸可缩减20%以上.此外,该方案也可以扩展为多方协同签名.展开更多
基金Key Program of National Natural Science Foundation of China,No.41930757National Natural Science Foundation of China,No.42371285。
文摘This study explores the impact of intergenerational differences on farmers' terrace abandonment in response to increasing intergenerational differentiation among rural households and the practical issue of terrace abandonment. Logit and Tobit models are employed to conduct empirical analysis and it is found that terrace abandonment increases sequentially among the new, middle, and old generations, confirming that intergenerational differences significantly influence whether farmers abandon terraces and the terrace abandonment scale. Village characteristics and government subsidies significantly influence farmers' terrace abandonment. An increase in the number of migrant workers in the village increases terrace abandonment among new and middle generation farmers, whereas an increase in the distance from the village to the county significantly increases terrace abandonment among old generation farmers. An increase in the village's total population significantly reduces terrace abandonment among new generation farmers. An increase in government subsidies significantly reduces terrace abandonment among middle and old generation farmers. The impact of intergenerational differences on terrace abandonment is more pronounced in low-altitude areas. To reduce terrace abandonment, it is necessary to promote terrace transfer, develop characteristic agriculture, improve terrace farming subsidies, and propose targeted strategies for the different generations of farmers.
文摘良性前列腺增生(benign prostatic hyperplasia,BPH)是引起中老年男性下尿路症状的常见原因,经尿道前列腺电切术(transurethral resection of the prostate,TURP)是泌尿外科治疗BPH的“金标准”^([1])。TURP对于前列腺体积较小的BPH患者疗效确切,但用于治疗前列腺体积>80 mL的BPH患者时,术中出血量明显增加,术后下尿路症状改善不明显,且术后持续膀胱冲洗时间以及导尿管留置时间延长^([2-3])。美国泌尿外科协会指南指出,钬激光或铥激光前列腺剜除术是目前大体积前列腺增生和小体积前列腺增生患者均适用的微创治疗方法^([4])。
文摘物联网和区块链等技术的兴起和发展,使得多方协同签名协议重新受到了关注.多方协同签名是一种特殊的数字签名,要求多个用户进行交互后共同对一个消息产生合法的签名,以达到认证的目的.优点在于相比起每个用户分别进行签名可以缩短尺寸,同时使用分布式的方法,任何一方都无法独自进行签名,防范了因为单个用户的密钥丢失或被劫持而导致被冒充身份的隐患.另一方面,量子计算机的进展对传统的公钥密码方案构成了潜在的威胁,美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)在2016年启动抗量子密码(post-quantum cryptography,PQC)的国际标准征集项目,并于2022年7月确定了被选为标准的算法.同时,基于其入选的数字签名方案(例如CRYSTALS-Dilithium)的协同签名方案也已经陆续出现.2019年,中国密码学会举办了全国密码算法设计竞赛,其中公钥组获得一等奖的Aigis-sig签名方案采用了与Dilithium类似的结构.基于Aigis-sig数字签名方案设计了一种两方协同签名方案,称之为Aitps,并根据其提供的参数进行了实例化和对比,得到了相比已有的所有基于Dilithium的两方协同签名方案更优的密钥和签名大小,例如在同等的安全强度下签名尺寸可缩减20%以上.此外,该方案也可以扩展为多方协同签名.
