San Diego State University

About: San Diego State University is a education organization based out in San Diego, California, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 12418 authors who have published 27950 publications receiving 1192375 citations. The organization is also known as: SDSU & San Diego State College.

Effects of Leadership Style and Followers' Cultural Orientation on Performance in Group and Individual Task Conditions

Abstract: We manipulated transformational and transactional leadership styles and compared them in individual and group task conditions to determine whether they had different impacts on individualists and c...

Recent Third Pole’s Rapid Warming Accompanies Cryospheric Melt and Water Cycle Intensification and Interactions between Monsoon and Environment: Multidisciplinary Approach with Observations, Modeling, and Analysis

Abstract: The Third Pole (TP) is experiencing rapid warming and is currently in its warmest period in the past 2,000 years. This paper reviews the latest development in multidisciplinary TP research ...

Pan-Arctic ice-wedge degradation in warming permafrost and its influence on tundra hydrology

Abstract: Ice wedges are common features of the subsurface in permafrost regions. They develop by repeated frost cracking and ice vein growth over hundreds to thousands of years. Ice-wedge formation causes the archetypal polygonal patterns seen in tundra across the Arctic landscape. Here we use field and remote sensing observations to document polygon succession due to ice-wedge degradation and trough development in ten Arctic localities over sub-decadal timescales. Initial thaw drains polygon centres and forms disconnected troughs that hold isolated ponds. Continued ice-wedge melting leads to increased trough connectivity and an overall draining of the landscape. We find that melting at the tops of ice wedges over recent decades and subsequent decimetre-scale ground subsidence is a widespread Arctic phenomenon. Although permafrost temperatures have been increasing gradually, we find that ice-wedge degradation is occurring on sub-decadal timescales. Our hydrological model simulations show that advanced ice-wedge degradation can significantly alter the water balance of lowland tundra by reducing inundation and increasing runoff, in particular due to changes in snow distribution as troughs form. We predict that ice-wedge degradation and the hydrological changes associated with the resulting differential ground subsidence will expand and amplify in rapidly warming permafrost regions. The polygonal patterns in permafrost regions are caused by the formation of ice wedges. Observations of polygon evolution reveal that rapid ice-wedge melting has occurred across the Arctic since 1950, altering tundra hydrology.

The association of school environments with youth physical activity.

Abstract: Objectives. This study assessed the association of school environmental characteristics with student physical activity on campus. Methods. Physical activity areas (n= 137) at 24 public middle schools were assessed for area type, size, and improvements (e.g., basketball courts). Student physical activity and the presence of equipment and supervision were directly observed before school, after lunch, and after school. Results. Environmental characteristics explained 42% of the variance in the proportion of girls who were physically active and 59% of the variance for boys. Conclusions. School environments with high levels of supervision and improvements stimulated girls and boys to be more physically active. (Am J Public Health. 2001;91:618‐620)

Metagenomic analysis of the microbial community associated with the coral Porites astreoides.

Abstract: The coral holobiont is a dynamic assemblage of the coral animal, zooxanthellae, endolithic algae and fungi, Bacteria,Archaea and viruses Zooxanthellae and some Bacteria form relatively stable and species-specific associations with corals Other associations are less specific; coral-associated Archaea differ from those in the water column, but the same archaeal species may be found on different coral species It has been hypothesized that the coral animal can adapt to differing ecological niches by 'switching' its microbial associates In the case of corals and zooxanthellae, this has been termed adaptive bleaching and it has important implications for carbon cycling within the coral holobiont and ultimately the survival of coral reefs However, the roles of other components of the coral holobiont are essentially unknown To better understand these other coral associates, a fractionation procedure was used to separate the microbes, mitochondria and viruses from the coral animal cells and zooxanthellae The resulting metagenomic DNA was sequenced using pyrosequencing Fungi, Bacteria and phage were the most commonly identified organisms in the metagenome Three of the four fungal phyla were represented, including a wide diversity of fungal genes involved in carbon and nitrogen metabolism, suggesting that the endolithic community is more important than previously appreciated In particular, the data suggested that endolithic fungi could be converting nitrate and nitrite to ammonia, which would enable fixed nitrogen to cycle within the coral holobiont The most prominent bacterial groups were Proteobacteria (68%), Firmicutes (10%), Cyanobacteria (7%) and Actinobacteria (6%) Functionally, the bacterial community was primarily heterotrophic and included a number of pathways for the degradation of aromatic compounds, the most abundant being the homogentisate pathway The most abundant phage family was the ssDNA Microphage and most of the eukaryotic viruses were most closely related to those known to infect aquatic organisms This study provides a metabolic and taxonomic snapshot of microbes associated with the reef-building coral Porites astreoides and presents a basis for understanding how coral-microbial interactions structure the holobiont and coral reefs