微调自己的SAM 2 分割模型
Meta 的 Segment Anything Model 2 (SAM 2) 是分割技术的最新创新。它是 Meta 的第一个统一模型，可以实时分割图像和视频中的对象。但是，如果 SAM 2 已经可以分割任何东西，为什么还要对其进行微调呢？
外国男子坐牢15年，妻子生4个娃？自称偷运精子出狱,医生表示怀疑
最近，一位巴勒斯坦男子的神奇经历引发了很多媒体的关注，因为他蹲监狱15年，这期间竟然有了4个孩子...
《自然》（20220818出版）一周论文导读
Abstract:Pumps are transport mechanisms in which direct currents result from a cyclic evolution of the potential. As Thouless showed， the pumping process can have topological origins， when considering the motion of quantum particles in spatially and temporally periodic potentials. However， the periodic evolution that drives these pumps has always been assumed to be imparted from outside， as has been the case in the experimental systems studied so far. Here we report on an emergent mechanism for pumping in a quantum gas coupled to an optical resonator， where we observe a particle current without applying a periodic drive. The pumping potential experienced by the atoms is formed by the self-consistent cavity field interfering with the static laser field driving the atoms. Owing to dissipation， the cavity field evolves between its two quadratures， each corresponding to a different centrosymmetric crystal configuration. This self-oscillation results in a time-periodic potential analogous to that describing the transport of electrons in topological tight-binding models， such as the paradigmatic Rice–Mele pump. In the experiment， we directly follow the evolution by measuring the phase winding of the cavity field with respect to the driving field and observing the atomic motion in situ. The observed mechanism combines the dynamics of topological and open systems， and features characteristics of continuous dissipative time crystals.
明查｜未接种疫苗的精子涨价400%？
科学研究表明，新冠疫苗不会对男性生育能力产生显著负面影响，而感染新冠在一定程度上会削弱男性生育能力。近日，有网友在推特上放出一张新闻网站截图，标题为“未接种疫苗的精子在精子库中获得400%的涨价”。