Power-processing unit

Power-processing unit uses AC buses (30, 32) to supply all current dependent needs such as connections (54, 56) to an ion thruster through an inductor (88) and the primary of a transformer (90), to assure limited currents to such loads. Where temperature control is also required, such as to the main discharge vaporizer heater connection (36, 38), switches (100, 102) are serially connected with inductor (96) and the primary of transformer (98). Temperature sensor (104) controls the switches (100, 102) for temperature regulation

Emission current control system for multiple hollow cathode devices

An emission current control system for balancing the individual emission currents from an array of hollow cathodes has current sensors for determining the current drawn by each cathode from a power supply. Each current sensor has an output signal which has a magnitude proportional to the current. The current sensor output signals are averaged, the average value so obtained being applied to a respective controller for controlling the flow of an ion source material through each cathode. Also applied to each controller are the respective sensor output signals for each cathode and a common reference signal. The flow of source material through each hollow cathode is thereby made proportional to the current drawn by that cathode, the average current drawn by all of the cathodes, and the reference signal. Thus, the emission current of each cathode is controlled such that each is made substantially equal to the emission current of each of the other cathodes. When utilized as a component of a multiple hollow cathode ion propulsion motor, the emission current control system of the invention provides for balancing the thrust of the motor about the thrust axis and also for preventing premature failure of a hollow cathode source due to operation above a maximum rated emission current

Directly Measured Denitrification Reveals Oyster Aquaculture and Restored Oyster Reefs Remove Nitrogen at Comparable High Rates

Coastal systems are increasingly impacted by over-enrichment of nutrients, which has cascading effects for ecosystem functioning. Oyster restoration and aquaculture are both hypothesized to mitigate excessive nitrogen (N) loads via benthic denitrification. The degree to which these management activities perform similar functions for removing N, however, has not been extensively examined in New England, a place where nutrient runoff is high and increasing oyster (Crassostrea virginica) restoration and aquaculture activity is taking place. Here, we use a novel in situ methodology to directly measure net N2 and O2 fluxes across the sediment-water interface in a shallow (~1 m) coastal pond in southern Rhode Island. We collected data seasonally during 2013 and 2014 at restored oyster reefs, oyster aquaculture, oyster cultch (shell), and bare sediment. Restored oyster reefs and aquaculture had the highest mean (±SE) denitrification rates, 581.9 (±164.2) and 346 (±168.6) μmol N2−N m−2 h−1, respectively, and are among the highest recorded for oyster-dominated environments. Denitrification rates at sites with oyster cultch were 60.9 (±44.3) μmol N2−N m−2 h−1, which is substantially less than the sites with active oysters but still more than 50% higher than denitrification rates measured in bare sediment (24.4 ± 10.1 μmol N2–N m−2 h−1). The increase in denitrification rates at treatments, however, varied by season and the greatest rates for restored reefs were in the fall. Overall, the greatest aggregate denitrification rates occurred in the fall. Sediment oxygen demand (SOD) followed similar patterns but with greater overall rates in the summer, and displayed a strong linear relationship with denitrification (R2 = 0.93). Our results demonstrate that habitats associated with live oysters have higher net denitrification rates and that oyster reef restoration and oyster aquaculture may provide similar benefits to the ecosystem in terms of N removal. However, gas fluxes may also be affected where three-dimensional structure is introduced via oyster shell cultch and this appears to be seasonally-dependent. These data will be important for managers as they incorporate oysters into nutrient reduction strategies and consider system-level trade-offs in services provided by oyster reef restoration and aquaculture activities

Directly Measured Denitrification Reveals Oyster Aquaculture and Restored Oyster Reefs Remove Nitrogen at Comparable High Rates

Coastal systems are increasingly impacted by over-enrichment of nutrients, which has cascading effects for ecosystem functioning. Oyster restoration and aquaculture are both hypothesized to mitigate excessive nitrogen (N) loads via benthic denitrification. The degree to which these management activities perform similar functions for removing N, however, has not been extensively examined in New England, a place where nutrient runoff is high and increasing oyster (Crassostrea virginica) restoration and aquaculture activity is taking place. Here, we use a novel in situ methodology to directly measure net N2 and O2 fluxes across the sediment-water interface in a shallow (~1 m) coastal pond in southern Rhode Island. We collected data seasonally during 2013 and 2014 at restored oyster reefs, oyster aquaculture, oyster cultch (shell), and bare sediment. Restored oyster reefs and aquaculture had the highest mean (±SE) denitrification rates, 581.9 (±164.2) and 346 (±168.6) μmol N2−N m−2 h−1, respectively, and are among the highest recorded for oyster-dominated environments. Denitrification rates at sites with oyster cultch were 60.9 (±44.3) μmol N2−N m−2 h−1, which is substantially less than the sites with active oysters but still more than 50% higher than denitrification rates measured in bare sediment (24.4 ± 10.1 μmol N2–N m−2 h−1). The increase in denitrification rates at treatments, however, varied by season and the greatest rates for restored reefs were in the fall. Overall, the greatest aggregate denitrification rates occurred in the fall. Sediment oxygen demand (SOD) followed similar patterns but with greater overall rates in the summer, and displayed a strong linear relationship with denitrification (R2 = 0.93). Our results demonstrate that habitats associated with live oysters have higher net denitrification rates and that oyster reef restoration and oyster aquaculture may provide similar benefits to the ecosystem in terms of N removal. However, gas fluxes may also be affected where three-dimensional structure is introduced via oyster shell cultch and this appears to be seasonally-dependent. These data will be important for managers as they incorporate oysters into nutrient reduction strategies and consider system-level trade-offs in services provided by oyster reef restoration and aquaculture activities

Redescription of Typosyllis aciculata

5 p. : ill. ; 24 cm.Includes bibliographical references (p. 5)

Effects of exotic soybean genotype on growth performance, nutrient digestibility, and carcass traits in finishing pigs

Compared to a corn-soybean meal control, added-fat from tallow, soybean oil, and dry-extruded whole soybeans (DEWS) improved ADG, F/G, and digestibility of DM and N. Feeding tallow increased belly firmness but also increased backfat thickness compared to diets with soy oil and DEWS. Comparisons among soybean genotypes indicated that high oleic acid soybeans supported greater growth performance than soybeans with high palmitic acid content. However, soybean genotype had no effect on carcass or meat quality measurements.; Swine Day, Manhattan, KS, November 19, 199

Mental health problems among 4–17-year-olds with hearing problems : results from a nationally representative study

OBJECTIVE : This study aimed to characterize the risk of mental health problems among a representative sample of 6,310 4–17-year-olds, 147 of whom had parent-reported hearing problems. METHODS : The study used data from the Young Minds Matter survey. The Diagnostic Interview Schedule for Children (DISC-IV) assessed prevalence of mood, anxiety and behavioural disorders. The Strengths and Difficulties Questionnaire (SDQ) assessed social and emotional problems. Logistic regression models were used to estimate odds of having mental health problems adjusting for child factors (speech and language problems, global health, age and gender), family factors (family structure, parent income, education, financial strain and psychological distress) and school-related factors (bullying, school liking, school absence). RESULTS : In unadjusted analyses, children and young people with hearing problems had substantially higher odds of most mental health problems. Hearing problems were not associated with any mental health problem among 4–11-year-olds after adjusting for other child factors. After adjustments for child, family and school-related factors, 12–17-year-olds with a hearing problem remained at greater risk of social phobia and generalized anxiety (DISC-IV), and of peer and emotional problems (SDQ). CONCLUSIONS : Clinicians caring for children and young people with hearing problems should be alert for heightened risk of specific mental health problems based on age and the nature of hearing problems. Understanding a wider range of correlates associated with the higher prevalence of mental health problems may allow health professionals to be more informed about the nature of mental health problems that are comorbid to hearing problems.KJH was supported by the Australian Research Centre of Excellence for Children and Families over the Life Course [grant No. CE140100027]. AL was supported by a National Health and Medical Research Council Early Career Fellowship [grant No. 1072593]. The Young Minds Matter survey was initiated and funded by the Australian Government Department of Health.https://www.tandfonline.com/toc/ihbc202018-05-16hj2018Speech-Language Pathology and Audiolog

Complex patterns of human antisera reactivity to novel 2009 H1N1 and historical H1N1 influenza strains

Background: During the 2009 influenza pandemic, individuals over the age of 60 had the lowest incidence of infection with approximately 25% of these people having pre-existing, cross-reactive antibodies to novel 2009 H1N1 influenza isolates. It was proposed that older people had pre-existing antibodies induced by previous 1918-like virus infection(s) that cross-reacted to novel H1N1 strains. Methodology/Principal Findings: Using antisera collected from a cohort of individuals collected before the second wave of novel H1N1 infections, only a minority of individuals with 1918 influenza specific antibodies also demonstrated hemagglutination-inhibition activity against the novel H1N1 influenza. In this study, we examined human antisera collected from individuals that ranged between the ages of 1 month and 90 years to determine the profile of seropositive influenza immunity to viruses representing H1N1 antigenic eras over the past 100 years. Even though HAI titers to novel 2009 H1N1 and the 1918 H1N1 influenza viruses were positively associated, the association was far from perfect, particularly for the older and younger age groups. Conclusions/Significance: Therefore, there may be a complex set of immune responses that are retained in people infected with seasonal H1N1 that can contribute to the reduced rates of H1N1 influenza infection in older populations. © 2012 Carter et al

Seroprevalence following the second wave of pandemic 2009 H1N1 influenza in Pittsburgh, PA, USA

Background: In April 2009, a new pandemic strain of influenza infected thousands of persons in Mexico and the United States and spread rapidly worldwide. During the ensuing summer months, cases ebbed in the Northern Hemisphere while the Southern Hemisphere experienced a typical influenza season dominated by the novel strain. In the fall, a second wave of pandemic H1N1 swept through the United States, peaking in most parts of the country by mid October and returning to baseline levels by early December. The objective was to determine the seroprevalence of antibodies against the pandemic 2009 H1N1 influenza strain by decade of birth among Pittsburgh-area residents. Methods and Findings: Anonymous blood samples were obtained from clinical laboratories and categorized by decade of birth from 1920-2009. Using hemagglutination-inhibition assays, approximately 100 samples per decade (n = 846) were tested from blood samples drawn on hospital and clinic patients in mid-November and early December 2009. Age specific seroprevalences against pandemic H1N1 (A/California/7/2009) were measured and compared to seroprevalences against H1N1 strains that had previously circulated in the population in 2007, 1957, and 1918. (A/Brisbane/59/2007, A/Denver/1/ 1957, and A/South Carolina/1/1918). Stored serum samples from healthy, young adults from 2008 were used as a control group (n = 100). Seroprevalences against pandemic 2009 H1N1 influenza varied by age group, with children age 10-19 years having the highest seroprevalence (45%), and persons age 70-79 years having the lowest (5%). The baseline seroprevalence among control samples from 18-24 year-olds was 6%. Overall seroprevalence against pandemic H1N1 across all age groups was approximately 21%. Conclusions: After the peak of the second wave of 2009 H1N1, HAI seroprevalence results suggest that 21% of persons in the Pittsburgh area had become infected and developed immunity. Extrapolating to the entire US population, we estimate that at least 63 million persons became infected in 2009. As was observed among clinical cases, this sero-epidemiological study revealed highest infection rates among school-age children. © 2010 Zimmer et al

The Human Cathelicidin LL-37 Preferentially Promotes Apoptosis of Infected Airway Epithelium

Cationic host defense peptides are key, evolutionarily conserved components of the innate immune system. The human cathelicidin LL-37 is an important cationic host defense peptide up-regulated in infection and inflammation, specifically in the human lung, and was shown to enhance the pulmonary clearance of the opportunistic pathogen Pseudomonas aeruginosa in vivo by as yet undefined mechanisms. In addition to its direct microbicidal potential, LL-37 can modulate inflammation and immune mechanisms in host defense against infection, including the capacity to modulate cell death pathways. We demonstrate that at physiologically relevant concentrations of LL-37, this peptide preferentially promoted the apoptosis of infected airway epithelium, via enhanced LL-37-induced mitochondrial membrane depolarization and release of cytochrome c, with activation of caspase-9 and caspase-3 and induction of apoptosis, which only occurred in the presence of both peptide and bacteria, but not with either stimulus alone. This synergistic induction of apoptosis in infected cells was caspase-dependent, contrasting with the caspase-independent cell death induced by supraphysiologic levels of peptide alone. We demonstrate that the synergistic induction of apoptosis by LL-37 and Pseudomonas aeruginosa required specific bacteria-epithelial cell interactions with whole, live bacteria, and bacterial invasion of the epithelial cell. We propose that the LL-37-mediated apoptosis of infected, compromised airway epithelial cells may represent a novel inflammomodulatory role for this peptide in innate host defense, promoting the clearance of respiratory pathogens