Satellite Cell Proliferative Compartments in Growing Skeletal Muscles

AbstractThe cell cycle time of satellite cells in growing rats was determined to be approximately 32 hr, with an S-phase of 14 hr. The estimated cycle time was the same for satellite cells in both oxidative soleus and glycolytic EDL muscles and is consistent with the rate at which myonuclei are produced during growth. Continuous infusion of bromodeoxyuridine (BrdU) was used to determine if all satellite cells had the same cycle timein vivo.Approximately 80% of the satellite cell population was readily labeled over the first 5 days of continuous infusion. Remaining satellite cells accumulated label at a much slower rate and were still not completely saturated after an additional 9 days of infusion. Only a small portion of the cells labeled with BrdU during the first 5 days could be labeled with a second label ([3H]thymidine) during tandem continuous infusion experiments, suggesting that they pass through a limited number of mitotic divisions prior to fusion. These results suggest that satellite cells in growing oxidative and glycolytic skeletal muscles can be subdivided into two distinct compartments. About 80% divide with a 32-hr cell cycle duration and are responsible chiefly for providing myonuclei to growing fibers. The remaining 20% of the cells divide more slowly, probably because the cells enter a G0-phase between mitotic divisions. These reserve cells, through asymmetric divisions, may generate the myonuclei-producing satellite cell population. Proliferative potential for regeneration and adaptive responses is likely located in this reserve population

Bacterial dynamics and community structure in the York River estuary

Bacterial community dynamics were investigated over seasonal and basin scales within the York River, VA, estuary. Various parameters characterizing bacterioplankton dynamics were measured weekly at a single station (March 1996 through May 1997) and monthly at six stations (June 1996 through May 1997) spanning the entire salinity gradient (0 - ca. 20 psu over 60 km). Bacterial abundance and production were found to be high throughout the estuary. Bacterial abundance ranged from 4.4 x 108 to 1.3 x 1010 cells-liter-1Incorporation of 3H-thymidine ranged from 10 to 863 pmol-liter-1-hr-1 while 3H-leucine incorporation rates ranged from 25 to 1963 pmol-liter -1-hr-1. Clear seasonal trends were apparent. The highest values of abundance and incorporation were found during the summer months. On a basin scale, bacterial properties were strongly related to changes in salinity. Although there is a great deal of variability from month to month, two opposing trends were consistently found: bacterial abundance increased from freshwater to the mouth of the river, while incorporation rates decreased from freshwater to the mouth. These patterns imply a strong landward gradient in specific growth rates. Growth rates determined by a two-dimensional box model were indeed higher upstream, but net growth rates were highest near the mouth. This explains how biomass can accumulate downstream even though production decreases. The box-model was also used to investigate the role of circulation in the distribution of bacterial cells. Dispersion rates were greater than net growth rates, indicating that dispersion controlled bacterial distribution during the study period. However, gross growth and removal rates were generally greater than dispersion rates, indicating the potential importance of biological processes to bacterial community structure within the estuary. BIOLOG plates were used to determine if differences in bacterial community structure or metabolic capabilities occurred over time or space. Two distinct bacterial communities separated by temperature were found over the course of a year at the VIMS pier. Four distinct communities separated by temperature and salinity were found over the course of a year along the salinity gradient. Thus, temperature, salinity, circulation and removal processes are the dominant processes controlling bacterial dynamics in the York River estuary

State and local level implementation of schoolwide positive behavior support: An examination of the Texas Behavior Support Initiative (TBSI).

This study examined the current status of schoolwide positive behavior support efforts in Texas. The study specifically (a) examined the impact of statewide positive behavior interventions and supports (PBIS) training on the rates of discipline records, in-school ¬suspensions, out-¬of¬-school suspensions, disciplinary alternative education placements, and expulsions of public schools in Texas; (b) investigated the overall effectiveness of schoolwide positive behavior support; and (c) determined the differences between rates of discipline records, in-school ¬suspensions, out-¬of¬-school suspensions, disciplinary alternative education placements, and expulsions in schools participating in the Texas Behavior Support Initiative (TBSI): Schoolwide PBS Project when compared with matching schools who did not participate in the project. This study demonstrated that schools can significantly reduce problem behavior in their schools when implementing PBIS with fidelity. Creating effective systems of PBIS required training, coaching, and on¬site technical assistance by trained and experienced PBIS facilitators

Migraine and Major Depression: A Longitudinal Study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72886/1/j.1526-4610.1994.hed3407387.x.pd

Automatic incorporation of context and primary source for a critical media experience

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 139-145).Falsehoods come in many forms. Politicians and advertisers make false claims, newsrooms and bloggers make mistakes, and the ease of publication and sharing makes it easy for even the most incredible theories to quickly spread. The risk of interpreting fiction as truth is significant and it is only increasing. How can technology protect consumers from falling into the traps set by dubious information? This thesis is an exploration of the challenges and possibilities surrounding the implementation of interfaces that mitigate the effects of misinformation. It contains an analysis of the pitfalls, considerations, and opportunities in the space of digital credibility. Those lessons are then applied to Truth Goggles, a technology prototype that attempts to trigger critical thinking in digital media consumers and codify the process of fair analysis.by Daniel Schultz.S.M

Chronopolis, University of North Texas, MetaArchive: Preservation Cooperation

This presentation discusses how preservation systems can share objects and specifically a collaboration between Chronopolis, MetaArchive, and the University of North Texas (UNT)