How the New Web Generations are Changing Library and Information Services

The new Web generations are influencing the minds and changing the habits of software developers and end users. Users, librarians, and information services professionals can interact more efficiently, creating additional information and content and generating knowledge. This new scenario is also changing the behavior of information providers and users in health sciences libraries. This article reviews the new Web environments and tools that give librarians opportunities to tailor their services better, and gives some examples of the advantages and disadvantages for them and their users. Librarians need to adapt to the new mindset of users, linking new technologies, information, and people.     

Coherence estimate between a random and a periodic signal: Bias, variance, analytical critical values, and normalizing transforms

The present work deals with recent results on the sampling distribution of the magnitude-squared coherence (also called just coherence) estimate between a random (Gaussian) and a periodic signal, in order to obtain analytical critical values, alternative expressions for the probability density function (PDF) as well as the variance and bias of the estimate. A comparison with the more general case of coherence estimation when both signals are Gaussian was also provided. The results indicate that the smaller the true coherence (TC) values the closer both distributions become. The behaviour of variance and bias as a function of the number of data segments and the TC is similar for both coherence estimates. Additionally, the effect of a normalizing function (Fisher's z transform) in the coherence estimated between a random and a periodic signal was also evaluated and normality has been nearly achieved. However, the variance was less equalized in comparison with coherence estimate between two Gaussian signals.