性交过频 小心不育

对于性交频繁的男子,常常导致精液量减少和精子密度降低,力和生存率下降,关卡而与卵子相会的能力大为减弱,受孕的机会就会相应减少。

哪些人应提防宫颈癌

有资料显示：我国每年约有5.3万女性死于宫颈癌，居女性癌症死亡的第2位。普查发现．宫颈糜烂的女性，其宫颈癌的发病率比宫颈光滑者高2倍。宫颈裂伤与宫颈癌的发生也有一定关系。虽然迄今为止，宫颈癌的真正病因尚不清楚。但近年来的研究与调查认为，其发病与早婚、早育、多产、宫颈糜烂、性交过频等因素有关。由于宫颈癌早期可无明显症状和体征，所以往往容易忽视，但以下宫颈癌高发人群需引起注意：

女性常吃甜食易患念珠菌阴道炎

造成念珠菌阴道炎的原因有很多，血糖或尿糖高只是其中一项。其他常见发病诱因有妊娠、大量应用免疫抑制剂和广谱抗生素、应用避孕药、穿紧身化纤内衣及肥胖、性交过频等。

房事中断射精有无危害

问：我今年38岁，性功能很强，听朋友说，性交过频，射精过多，容易引起肾虚，有损寿命；如果性交时强忍不射精，有利于健康延寿。请问性交时中断射精到底有没有危害？

Efficient nonlinear companding scheme for substantial reduction in peak-to-average power ratio of OFDM

Orthogonal frequency division multiplexing(OFDM)produces a high peak-to-average power ratio(PAPR) that adversely affects high-speed OFDM data transmission. In order to reduce the high PAPR, an efficient nonlinear companding transform(NCT) function is proposed. With the proposed NCT function,the compression and expansion weights can be applied independently with suitably chosen function parameter values. As a result, the proposed function can easily maintain the average signal power approximately unchanged during the companding process.In this regard, the proposed function is superior to previously proposed schemes. Also, the simulations show the outstanding PAPR reduction performance of the proposed function. It is demonstrated that the proposed scheme performs well with nonlinear transmitter amplifiers and delivers superior error performance, compared with error function and exponential function based schemes.