immune response. The general immune response really decreases with aging [ 1 ], and there are some theories that point to the central role of declining immune system on the general aging as well as to the lifespan [ 2 – 4 ]. However, it is not clear that
Studies on the life-span of past scientists according to data of theChronicle of Major Events of Natural Sciences have found that the age of optimum peak value of scientific discovery is about half the peak value of their life-span. Achievements of those scientists who made a name before 25 years old are 44 percent more than average and their life efficiency is 1.7 times that of the average. Therefore it is an effective measure to train prococious scientists for a nation in her strive to catch up with or surpass world level in science.
Authors:Jacob B. Slyder, Beth R. Stein, Brent S. Sams, David M. Walker, B. Jacob Beale, Jeffrey J. Feldhaus, and Carolyn A. Copenheaver
forestry departments across ten major public universities in the United States; (2) within this same population compare self-citation practices and (3) compare the patterns of citation frequency that a paper received over its post-publication lifespan. Our
organs, it has to be suggested that thymus is the endogeneous determinator of the general (species) and individual life span. It is obvious that something is needed for the regulation of lifespan, as individual life cannot be infinite. The best solution
Authors:Cristina Sousa, Jorge Azevedo, Amélia Silva, Carlos Viegas, Rui Reis, Manuela Gomes, and Isabel Dias
This study aimed to assess serum total alkaline phosphatase (ALP) and its bone isoform (BALP) levels during the ageing and in different physiologic states of sheep, in order to expand the knowledge about the variation of these biomarkers over the sheep lifespan. Ninety female sheep were divided into nine groups of various ages and physiological states (dry, lactation and pregnancy). Serum ALP, BALP and mineral levels were determined by commercial immunoassay, molecular absorbance spectrophotometry and chemical luminescence for BALP determination. Serum ALP and BALP decreased as sheep aged, and no statistically significant differences were obtained between ewes in different physiologic states. The continuous decline of serum BALP concentration along the sheep lifespan, namely in mature and old sheep, is a sign of decreasing bone turnover associated with ageing. Serum calcium concentrations increased slightly until 2 years of age and then showed a tenuous but statistically significant decrease in mature sheep, while serum phosphorus maintained an uninterrupted decrease as sheep matured. The knowledge of serum values of bone biomarkers throughout the sheep lifespan may be useful in preclinical orthopaedic research studies and for animal science studies using sheep.
The World Wide Web is growing at an enormous speed, and has become an indispensable source for information and research. New
pages are constantly added, but there are additional processes as well: pages are moved or removed and/or their content changes.
We report here the results of an eight year long project started in 1998, when multiple search engines were used to identify
a set of pages containing the term informetrics. Data collection was repeated once a year for the last eight years (with the exception of 2000 and 2001) using both search
engines and revisiting previously identified pages. The results show that the number of pages grew from 866 in 1998 to 28,914
in 2006 — a 33-fold growth. Besides the obvious growth of the topic on the Web, we observed both decay (pages disappearing
from the Web) and modification. Even though most of the pages from 1998 either disappeared or ceased to contain the term informetrics, 165 pages (19.1%) still exist in 2006 and contain the search term. We followed the “fate” of these 165 pages: characterized
the publishers, the contents and the changes that occurred the whole period. In recent years e-print servers and publishers’
sites became sources of large number of pages related to informetrics. Longitudinal studies following the evolution of a topic on the Web are very important, since they provide insights about
content and the underlying Web processes.