An enantiornithine bird from the Lower Cretaceous of Queensland, Australia
Current classification of birds recognizes four subclasses: the Archaeornithes, the Enantiornithes, the Odontornithes and the Neornithes. Three of these subclasses were proposed during the nineteenth century, but the Enantiornithes was proposed only five years ago, based on material from the Lecho Formation (Maas-trichtian) of Salt a Province in Argentina1. Further material from Asia (Mongolia) and North America (Mexico) has been referred to the Enantiornithes2, all of it from the Campanian. Now, in addition, a small tibiotarsus found in the Lower Cretaceous (Albian) of Queensland not only represents the first bony material of Mesozoic birds from Australia, but is also the first reported occurrence of an enantiornithine bird in the Lower Cretaceous.
Early Cretaceous Feathers from Victoria
Unusually well preserved fossil feathers from Lower Cretaceous (VaIanginian-Aptian) claystones at Koonwarra, Victoria, are the oldest (c. 110-125 million years) bird remains yet found in the southern hemisphere, They are among the oldest bird remains known in the world, being antedated only by the toothed Archaeopteryx from the late Jurassic of Bavaria, and being more or less the same age as Gallornis from the Lower Cretaceous of France. The Victorian fossil feathers are evidence for essentially worldwide distribution of birds soon after the beginning of the Cretaceous, if not before. The feathers could conceivably have come from toothed birds.
The National PKI of Peru: a new certification hierarchy
In order to guarantee secure transactions through the Internet and to generate strong evidence that could be used in case of future legal disputes, several countries around the world have promoted and regulated the use of digital signatures based on Public Key Infrastructure (PKI). However, despite the high expectations, its implementation has achieved neither the desired results nor its globalization. Many of the reasons were discovered years ago, but they are still open problems for the scientific community nowadays. In order to consider the case of the national PKI of the Peruvian state as empirical evidence for studies that address the open problems, this article describes the details about a new certification hierarchy which is expected to overcome some of its predecessors’ limitations. It is also expected that the information disclosed in this article could be useful to other countries for making a preliminary assessment for possible cross-border recognition of Peruvian digital signatures.