77 research outputs found
NASA Image eXchange (NIX)
This paper discusses the technical aspects of and the project background for the NASA Image exchange (NIX). NIX, which provides a single entry point to search selected image databases at the NASA Centers, is a meta-search engine (i.e., a search engine that communicates with other search engines). It uses these distributed digital image databases to access photographs, animations, and their associated descriptive information (meta-data). NIX is available for use at the following URL: http://nix.nasa.gov./NIX, which was sponsored by NASAs Scientific and Technical Information (STI) Program, currently serves images from seven NASA Centers. Plans are under way to link image databases from three additional NASA Centers. images and their associated meta-data, which are accessible by NIX, reside at the originating Centers, and NIX utilizes a virtual central site that communicates with each of these sites. Incorporated into the virtual central site are several protocols to support searches from a diverse collection of database engines. The searches are performed in parallel to ensure optimization of response times. To augment the search capability, browse functionality with pre-defined categories has been built into NIX, thereby ensuring dissemination of 'best-of-breed' imagery. As a final recourse, NIX offers access to a help desk via an on-line form to help locate images and information either within the scope of NIX or from available external sources
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The identification of genes important in pseudomonas syringae pv. phaseolicola plant colonisation using in vitro screening of transposon libraries
The bacterial plant pathogen Pseudomonas syringae pv. phaseolicola (Pph) colonises the surface of common bean plants before moving into the interior of plant tissue, via wounds and stomata. In the intercellular spaces the pathogen proliferates in the apoplastic fluid and forms microcolonies (biofilms) around plant cells. If the pathogen can suppress the plant’s natural resistance response, it will cause halo blight disease. The process of resistance suppression is fairly well understood, but the mechanisms used by the pathogen in colonisation are less clear. We hypothesised that we could apply in vitro genetic screens to look for changes in motility, colony formation, and adhesion, which are proxies for infection, microcolony formation and cell adhesion. We made transposon (Tn) mutant libraries of Pph strains 1448A and 1302A and found 106/1920 mutants exhibited alterations in colony morphology, motility and biofilm formation. Identification of the insertion point of the Tn identified within the genome highlighted, as expected, a number of altered motility mutants bearing mutations in genes encoding various parts of the flagellum. Genes involved in nutrient biosynthesis, membrane associated proteins, and a number of conserved hypothetical protein (CHP) genes were also identified. A mutation of one CHP gene caused a positive increase in in planta bacterial growth. This rapid and inexpensive screening method allows the discovery of genes important for in vitro traits that can be correlated to roles in the plant interactio
Membrane anchoring stabilizes and favors secretion of New Delhi metallo-β-lactamase
Carbapenems, 'last-resort' β-lactam antibiotics, are inactivated by zinc-dependent metallo-β-lactamases (MBLs). The host innate immune response withholds nutrient metal ions from microbial pathogens by releasing metal-chelating proteins such as calprotectin. We show that metal sequestration is detrimental for the accumulation of MBLs in the bacterial periplasm, because those enzymes are readily degraded in their nonmetallated form. However, the New Delhi metallo-β-lactamase (NDM-1) can persist under conditions of metal depletion. NDM-1 is a lipidated protein that anchors to the outer membrane of Gram-negative bacteria. Membrane anchoring contributes to the unusual stability of NDM-1 and favors secretion of this enzyme in outer-membrane vesicles (OMVs). OMVs containing NDM-1 can protect nearby populations of bacteria from otherwise lethal antibiotic levels, and OMVs from clinical pathogens expressing NDM-1 can carry this MBL and the bla[subscript NDM] gene. We show that protein export into OMVs can be targeted, providing possibilities of new antibacterial therapeutic strategies.Kinship Foundation. Searle Scholars ProgramMassachusetts Institute of Technology. Department of Chemistr
A large genome-wide association study of age-related macular degeneration highlights contributions of rare and common variants.
This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/ng.3448Advanced age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, with limited therapeutic options. Here we report on a study of >12 million variants, including 163,714 directly genotyped, mostly rare, protein-altering variants. Analyzing 16,144 patients and 17,832 controls, we identify 52 independently associated common and rare variants (P < 5 × 10(-8)) distributed across 34 loci. Although wet and dry AMD subtypes exhibit predominantly shared genetics, we identify the first genetic association signal specific to wet AMD, near MMP9 (difference P value = 4.1 × 10(-10)). Very rare coding variants (frequency <0.1%) in CFH, CFI and TIMP3 suggest causal roles for these genes, as does a splice variant in SLC16A8. Our results support the hypothesis that rare coding variants can pinpoint causal genes within known genetic loci and illustrate that applying the approach systematically to detect new loci requires extremely large sample sizes.We thank all participants of all the studies included for enabling this research by their participation in these studies. Computer resources for this project have been provided by the high-performance computing centers of the University of Michigan and the University of Regensburg. Group-specific acknowledgments can be found in the Supplementary Note. The Center for Inherited Diseases Research (CIDR) Program contract number is HHSN268201200008I. This and the main consortium work were predominantly funded by 1X01HG006934-01 to G.R.A. and R01 EY022310 to J.L.H
MODELING MOOSE POPULATIONS FOR MANAGEMENT DECISION MAKING IN ALASKA
We took a previously described moose (Alces alces) model for the Kenai Peninsula, Alaska and enhanced its capabilities. The model produced year by year calculations of all pertinent population statistics and harvest by age class. The refined model was used to evaluate proposals for changes to hunting regulations predicted population trends over time (e.g., 3, 5, or 9 year durations) in response to various simulated management actions allowed decision makers to judge the relative merits of various harvest regimes. the model allowed planning for moderate to long-term, rather than reacting annually to short-term changes in weather, harvest, or public perceptions. Simulations allowed managers to evaluate various regulatory regimes, looking for those that produce desired outcomes on a long-term basis while considering impacts of severe winters. easy to understand graphics allowed for quick interpretations of model runs by administrators and the public, which facilitated the manager’s ability to demonstrate the consequences of a particular management action. the model and its results were accepted by the public and decision makers. Model output guided decision makers when evaluating proposed changes to harvest regulations
Strategies for Ph.D. completion: a critical reflection by completed Ph.D. candidates
The Ph.D. journey encompasses a range of varied experiences and emotions for the candidates undertaking the degree, their supervisors and the relevant administrative staff members. Although the emotions and experiences of each party vary, the common goal is for the candidate to complete the degree successfully in a timely manner. Current research suggests that the attrition rate for Ph.D. candidates is high and that, for those who do complete, the enrolment duration is longer than ideal. As a result, there is a need for evidence-based strategies to assist Ph.D. candidates to complete their degree in a timely manner. The purpose of this chapter is to reflect critically on the experiences of completing a Ph.D. from the perspective of two Ph.D. candidates. Specific milestones (e.g., confirmation of candidature) throughout the doctoral process are discussed and strategies offered to aid potentially in facilitating students’ successful doctoral completion. These strategies, primarily developed from reflection, may also be relevant for supervisors and administrative staff members. Ultimately, it is hoped that the implementation of the suggested strategies will produce optimal outcomes for all parties
Ethnic and gender differences in smoking and smoking cessation in a population of young adult air force recruits
Purpose. To examine gender and ethnic differences in smoking and smoking cessation in a population of young adult military, recruits. Design. A self-administered survey of demographics, tobacco use, and other health risk behaviors was administered at the start of basic military training. Setting. The study was conducted at Lackland Air Force Base, San Antonio, Texas, where all U.S. Air Force recruits complete basic military training. Subjects. All recruits who entered the U.S. Air Force between September 1995 and September 1996 participated in this study (n = 32,144; 100% participation rate). Measures. Recruits completed a written 53-item behavioral risk questionnaire. Measures examined in the present study included smoking status (ever having smoked a cigarette, current daily smoking, and quitting); demographics (ethnicity, gender, education, family, income, and age); smoking history; and nicotine dependence. Results. Rates of ever smoking, current daily smoking, and quitting were examined in multiple logistic regression analyses as a function of gender and ethnicity, controlling for age, education, and family income. Overall, 54% of recruits had ever smoked a cigarette and 24.9% smoked daily at the time of entry into basic military training. Smoking rates were highest among white and Native American recruits. Among whites, women were more likely to be a current daily smoker (31.6% vs. 29.4%; odds ratio [OR] = 1.18, 99% confidence intervals [CI] = 1.08-1.29). The opposite Pattern was observed among African-Americans (5.6% vs. 9.8%, respectively; OR = .57; CI = .41-.79). Current smokers had low levels of nicotine dependence compared with the general population of U.S. smokers, but whites tended to be more dependent than other ethnic groups. Cessation rates were similar for men and women but differed according to ethnicity, ranging from 15% among whites to 23% among Hispanics. Conclusions. These findings document important gender and ethnic differences in cigarette smoking among military recruits. Whites and Native Americans were more likely to smoke, less likely to quit, and more nicotine-dependent than other ethnic groups. Across gender/ethnicity groups, smoking rates were especially high among white women, with nearly one-third smoking daily until entry into basic training. Gender differences were not observed in cessation rates, but Hispanics were more likely than other ethnic groups to have quit smoking. The results highlight the need to develop effective cessation interventions for this population
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