Comparative analysis of inbreeding parameters and runs of homozygosity islands in 2 Italian autochthonous cattle breeds mainly raised in the Parmigiano-Reggiano cheese production region

Reggiana and Modenese are autochthonous cattle breeds, reared in the North of Italy, that can be mainly distinguished for their standard coat color (Reggiana is red, whereas Modenese is white with some pale gray shades). Almost all milk produced by these breeds is transformed into 2 mono-breed branded Parmigiano-Reggiano cheeses, from which farmers receive the economic incomes needed for the sustainable conservation of these animal genetic resources. After the setting up of their herd books in 1960s, these breeds experienced a strong reduction in the population size that was subsequently reverted starting in the 1990s (Reggiana) or more recently (Modenese) reaching at present a total of about 2,800 and 500 registered cows, respectively. Due to the small population size of these breeds, inbreeding is a very important cause of concern for their conservation programs. Inbreeding is traditionally estimated using pedigree data, which are summarized in an inbreeding coefficient calculated at the individual level (F_PED). However, incompleteness of pedigree information and registration errors can affect the effectiveness of conservation strategies. High-throughput SNP genotyping platforms allow investigation of inbreeding using genome information that can overcome the limits of pedigree data. Several approaches have been proposed to estimate genomic inbreeding, with the use of runs of homozygosity (ROH) considered to be the more appropriate. In this study, several pedigree and genomic inbreeding parameters, calculated using the whole herd book populations or considering genotyping information (GeneSeek GGP Bovine 150K) from 1,684 Reggiana cattle and 323 Modenese cattle, were compared. Average inbreeding values per year were used to calculate effective population size. Reggiana breed had generally lower genomic inbreeding values than Modenese breed. The low correlation between pedigree-based and genomic-based parameters (ranging from 0.187 to 0.195 and 0.319 to 0.323 in the Reggiana and Modenese breeds, respectively) reflected the common problems of local populations in which pedigree records are not complete. The high proportion of short ROH over the total number of ROH indicates no major recent inbreeding events in both breeds. ROH islands spread over the genome of the 2 breeds (15 in Reggiana and 14 in Modenese) identified several signatures of selection. Some of these included genes affecting milk production traits, stature, body conformation traits (with a main ROH island in both breeds on BTA6 containing the ABCG2, NCAPG, and LCORL genes) and coat color (on BTA13 in Modenese containing the ASIP gene). In conclusion, this work provides an extensive comparative analysis of pedigree and genomic inbreeding parameters and relevant genomic information that will be useful in the conservation strategies of these 2 iconic local cattle breeds.     

数字签名技术在医院电子病历中的设计与应用

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一种基于无理数加密算法的数字签名方案

为了提高现代网络信息传输的安全性,利用无理数小数点后数字的无穷性、无规律性、分布均匀性,提出一种全新的加密算法,并用它所产生的密钥流进行数字签名,实现身份验证不可抵赖、信息传输无篡改,确保信息传输的完整性、真实性,达到提高加密效率、相互认证的效果。     

一种基于Normal基椭圆曲线密码芯片的设计

文章设计了一款椭圆曲线密码芯片。实现了GF（2^233）域上normal基椭圆曲线数字签名和认证。并支持椭圆曲线参数的用户配置。在VLSI的实现上，提出了一种新的可支持GF（2^233）域和GF（p）域并行运算的normal基椭圆曲线VLSI架构。其架构解决了以往GF（p）CA算迟后于GF（2^233）域运算的问题，从而提高了整个芯片的运算吞吐率。基于SMIC 0．18μm最坏的工艺，综合后关键路径最大时延3．8ns，面积18mm^2；考虑布局布线的影响，芯片的典型的情况下，每秒可实现8000次签名或4500次认证。     

移动网络中的独立式安全管理系统

本文提出一种适用于移动网络的安全管理系统,由于访问网络能够独立地对漫游用户进行认证,所以称该系统为独立式安全管理(ISM).基于ISM设计一种漫游用户的认证协议,通过对协议的比较分析可以看出,相对于其它安全管理系统,ISM的突出优点是安全责任划分清晰、认证效率高.     

一种改进TSENG-JAN群签名的安全分析

本文对一种改进的Tseng-Jan群签名进行安全性分析,指出了该方案具有广义伪造性和相关性,即任何人可以对任意消息签名,管理员却不能对签名者进行追踪;且能够区分两个不同的签名是否来自于同一个人.     

计算机网络安全系统设计

分析了现代计算机网络所面临的威胁和各种安全问题,同时提出了在设计一个有关网络系统时应该考虑的一些安全问题,如网络安全策略与技术、网络的访问控制、网络数据加密技术、信息隐藏技术等安全问题。     

数字签名技术在解决密钥泄露方面的发展

密钥泄露对数字签名的危害越来越成为人们关注的焦点，该问题很难找到完全彻底的解决办法，只能尽可能减少其危害。对此专家和学者提出了很多新的数字签名机制，这里详细介绍了其中的一些，并指出它们各自的优缺点。针对在SiBIR数字签名机制中由于网络拥塞或攻击者的恶意拦截使得更新信息丢失造成signer和home base不能保持同步的问题，我们提出了超时同步机制。     

基于多代理的分步签名方案

首先对数字证书认证机制进行安全性分析，并结合RSA签名算法的自身特点和先验式秘密共享机制的发展现状提出了一种基于多代理的分步签名方案。该方案一方面解决了离线签名的效率问题，另一方面解决了传统签名的安全问题。最后结合分步签名的实现论证了方案的可行性。     

基于椭圆曲线的限制代理签名方案

基于椭圆曲线提出了一个限制代谢签名者的代理签名次数和代理签名期限的代理签名方案。原始签名者在代理签名有效期内，能限制代理签名者的代理签名次数，当代理签名有效期过后，能收回代理签名权。该方案克服了通常的代理签名方案中一旦原始签名者将答名权委托给代理签名者，就无法控制代理签名者的代理签名次数，无法收回代理签名权的缺点，该方案是基于椭圆曲线，采用一次一密签名构造的，具有安全性高，速度快，密钥量小，便于实现等优点。