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.

Recent change of Arctic tundra ecosystems from a net carbon dioxide sink to a source

Abstract: ARCTIC tundra has been a net sink for carbon dioxide during historic and recent geological times1–4, and large amounts of carbon are stored in the soils of northern ecosystems. Many regions of the Arctic are warmer now than they have been in the past5–10, and this warming may cause the soil to change from a carbon dioxide sink to a source by lowering the water table11–12, thereby accelerating the rate of soil decomposition (CO2 source)3,13–15 so that this dominates over photosynthesis (CO2 sink). Here we present data indicating that the tundra on the North Slope of Alaska has indeed become a source of carbon dioxide to the atmosphere. This change coincides with recent warming in the Arctic, whether this is due to increases in greenhouse gas concentrations in the atmosphere or to some other cause. Our results suggest that tundra ecosystems may exert a positive feedback on atmospheric carbon dioxide and greenhouse warming.

Lifetime prevalence of DSM-III-R psychiatric disorders among urban and rural Mexican Americans in California.

Abstract: Background The Mexican American Prevalence and Services Survey presents lifetime prevalence rates for 12 DSM-III-R psychiatric disorders in a sample of 3012 adults of Mexican origin by place of residence and nativity, and compares these results with those of population surveys conducted in the United States and Mexico. Methods The stratified random sample included noninstitutionalized persons aged 18 to 59 years of Mexican origin, who were residents of Fresno County, California. Psychiatric disorders were assessed using a modified version of the World Health Organization Composite International Diagnostic Interview in face-to-face interviews. Results Mexican immigrants had lifetime rates similar to those of Mexican citizens, while rates for Mexican Americans were similar to those of the national population of the United States. This difference is attributable to a prevalence rate for any disorder among immigrants of 24.9%, compared with 48.1% among US-born respondents. A higher prevalence for any disorder was reported in urban (35.7%) compared with town (32.1%) or rural (29.8%) areas. Multivariate analyses showed an adjusted effect of country of birth, but not of urban residence. Conclusions Despite very low education and income levels, Mexican Americans had lower rates of lifetime psychiatric disorders compared with rates reported for the US population by the National Comorbidity Survey. Psychiatric morbidity among Mexican Americans is primarily influenced by cultural variance rather than socioeconomic status or urban vs rural residence.

Pervasiveness and correlates of implicit attitudes and stereotypes

Abstract: Correspondence should be addressed to Brian A. Nosek, Department of Psychology, University of Virginia, 102 Gilmer Hall, Box 400400, Charlottesville, VA 22904, USA. E-mail: nosek@virginia.edu This research was supported by the National Institute of Mental Health (MH-41328, MH-01533, MH-57672, and MH-68447) and the National Science Foundation (SBR-9422241, SBR-9709924, and REC-0634041). The authors are grateful for technical support from N. Sriram, Ethan Sutin, and Lili Wu. Related information is available at http://briannosek.com/ and http://projectimplicit.net/ EUROPEAN REVIEW OF SOCIAL PSYCHOLOGY 2007, 1 – 53, iFirst article

Genomic analysis of uncultured marine viral communities

Abstract: Viruses are the most common biological entities in the oceans by an order of magnitude. However, very little is known about their diversity. Here we report a genomic analysis of two uncultured marine viral communities. Over 65% of the sequences were not significantly similar to previously reported sequences, suggesting that much of the diversity is previously uncharacterized. The most common significant hits among the known sequences were to viruses. The viral hits included sequences from all of the major families of dsDNA tailed phages, as well as some algal viruses. Several independent mathematical models based on the observed number of contigs predicted that the most abundant viral genome comprised 2–3% of the total population in both communities, which was estimated to contain between 374 and 7,114 viral types. Overall, diversity of the viral communities was extremely high. The results also showed that it would be possible to sequence the entire genome of an uncultured marine viral community.

Functional metagenomic profiling of nine biomes

Abstract: Microbial activities shape the biogeochemistry of the planet and macroorganism health. Determining the metabolic processes performed by microbes is important both for understanding and for manipulating ecosystems (for example, disruption of key processes that lead to disease, conservation of environmental services, and so on). Describing microbial function is hampered by the inability to culture most microbes and by high levels of genomic plasticity. Metagenomic approaches analyse microbial communities to determine the metabolic processes that are important for growth and survival in any given environment. Here we conduct a metagenomic comparison of almost 15 million sequences from 45 distinct microbiomes and, for the first time, 42 distinct viromes and show that there are strongly discriminatory metabolic profiles across environments. Most of the functional diversity was maintained in all of the communities, but the relative occurrence of metabolisms varied, and the differences between metagenomes predicted the biogeochemical conditions of each environment. The magnitude of the microbial metabolic capabilities encoded by the viromes was extensive, suggesting that they serve as a repository for storing and sharing genes among their microbial hosts and influence global evolutionary and metabolic processes.