美国政府宣布全面限制哈佛大学外国学生签证
今日美国总统特朗普签署公告，宣布为维护国家安全，暂停外国公民以学习或参加哈佛大学交流项目为目的入境美国。
该公告将禁止任何哈佛大学的学生以F、M或J类签证作为非移民身份进入美国，同时授权国务院吊销目前在读学生的签证。该公告不适用于通过学生交流签证项目（SEVP）就读于其他美国大学的外国人，并豁免那些被认定符合国家利益的外国人。
美国白宫
📮投稿 ☘️频道 🍱狗东
BY 科技圈🎗在花频道📮
Secret Chats are one of the service’s additional security features; it allows messages to be sent with client-to-client encryption. This setup means that, unlike regular messages, these secret messages can only be accessed from the device’s that initiated and accepted the chat. Additionally, Telegram notes that secret chats leave no trace on the company’s services and offer a self-destruct timer.
Bitcoin is built on a distributed digital record called a blockchain. As the name implies, blockchain is a linked body of data, made up of units called blocks that contain information about each and every transaction, including date and time, total value, buyer and seller, and a unique identifying code for each exchange. Entries are strung together in chronological order, creating a digital chain of blocks. “Once a block is added to the blockchain, it becomes accessible to anyone who wishes to view it, acting as a public ledger of cryptocurrency transactions,” says Stacey Harris, consultant for Pelicoin, a network of cryptocurrency ATMs. Blockchain is decentralized, which means it’s not controlled by any one organization. “It’s like a Google Doc that anyone can work on,” says Buchi Okoro, CEO and co-founder of African cryptocurrency exchange Quidax. “Nobody owns it, but anyone who has a link can contribute to it. And as different people update it, your copy also gets updated.”
在花软件新闻投稿频道 from us