Drop size-dependent chemical composition in clouds and fogs

December 2001.Also issued as author's dissertation (Ph.D.) -- Colorado State University, 2002.Includes bibliographical references.Cloud drop composition varies as function of drop size. More sophisticated atmospheric chemistry models predict this and observations at many locations around the world by multiple techniques confirm this. This variation can influence the cloud processing of atmospheric species. Aqueous-phase reaction and atmospheric removal rates for scavenged species, among other processes, can be affected by drop size-dependent composition. Inferences to these processes drawn upon single bulk cloud composition measurements can be misleading according to observations obtained using cloud water collectors that separate drops into two or more size­ resolved fractions. Improved measurements of size-dependent drop composition are needed to further examine these and related issues. Two active multi-stage cloud water collectors were developed for sampling super-cooled drops in mixed-phase clouds and warm cloud drops, respectively. Both use the principles of cascade inertial impaction to separate drops into three fractions (super-cooled drop collector) and five fractions (warm cloud drop collector). While calibration suggests there is more drop overlap between stages than desired, consistently different drop fractions are still collected. FROSTY - the super-cooled drop collector - has been used successfully to obtain size-resolved drop composition information during two field campaigns in Colorado. While the data are limited, FROSTY's field performance appears to be reasonably consistent during individual cloud events, although not predictable based solely upon its collection efficiency curves. Additional factors must be considering in evaluating its performance in future campaigns. Nevertheless, the ability to obtain consistent size-resolved drop composition information from super-cooled clouds was not previously possible. Field data indicate that the warm cloud collector - the CSU 5-Stage - is able to resolve variations in the drop size-dependent composition not discernible with the two-stage size-fractionating Caltech Active Strand Cloud water Collector (sf-CASCC). Field performance evaluations suggest that the 5-Stage and the sf-CASCC compare well to each other for the range of sampling conditions experienced. Both collectors' performances differ from measurements made by the Caltech Active Strand Cloud water Collector #2 (CASCC2) in some specific sampling conditions, but otherwise agreement between the three collectors is good. Where the sf-CASCC indicates little drop variation in an orographic cloud study at Whiteface Mtn., NY, the 5-Stage indicates up to a factor of two difference may exist between the maximum and minimum drop concentrations for the major inorganic ions (ammonium, nitrate and sulfate). The sf-CASCC data suggest that typically a factor of 3 - 5 difference exists between large and small drop species' concentrations in radiation fogs measured in Davis, CA Concurrent 5-Stage samples suggest the actual variation may be up to at least a factor of 4 - 5 greater, and that the smallest drops (approximately < 11 µmin diameter) are principally responsible for the strong observed concentration gradients between sizes. While the data are limited, the 5-Stage's results are consistent for all of the sample sets obtained during both field campaigns. Data from the 5-Stage emphasize that cloud drop chemical composition cannot be considered separately from the sampled cloud's microphysics and dynamics. Interpreting the 5-Stage's results necessarily draws upon both. During the Davis campaign, additional measurements were performed to investigate species removal from the atmosphere via drop deposition and gas/liquid partitioning in-fog. Although subject to confounding effects, these investigations benefited from the additional insight 5-Stage data provided into the processes occurring. In particular, 5-Stage data and between-fog aerosol measurements suggest that deposition of the largest fog drops resulted in the relative removal of coarse mode aerosol particles from the atmosphere. 5-Stage data and gas-phase measurements suggest the ammonia/ammonium system may not be at equilibrium and provide some information about the nitrous acid/nitrite system not otherwise available. The 5-Stage has the potential to be a valuable tool in investigating the effects of fog and fog processing on the fate of ambient species.Sponsored by USEPA under grant NCERQA R82-3979-010; STAR Fellowship U-915364; NSF under grants ATM-9509596, ATM-9712603, and ATM-9980540; and the San Joaquin Valleywide Air Pollution Study Agency

Feedback valence affects auditory perceptual learning independently of feedback probability.

Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they were doing equally well, while 10% positive or 90% negative feedback informed them they were doing equally badly. In all conditions the feedback was random in relation to the listeners' responses (because the task was to discriminate three identical tones), yet both the valence (negative vs. positive) and the probability of feedback (10% vs. 90%) affected learning. Feedback that informed listeners they were doing badly resulted in better post-training performance than feedback that informed them they were doing well, independent of valence. In addition, positive feedback during training resulted in better post-training performance than negative feedback, but only positive feedback indicating listeners were doing badly on the task resulted in learning. As we have previously speculated, feedback that better reflected the difficulty of the task was more effective in driving learning than feedback that suggested performance was better than it should have been given perceived task difficulty. But contrary to expectations, positive feedback was more effective than negative feedback in driving learning. Feedback thus had two separable effects on learning: feedback valence affected motivation on a subjectively difficult task, and learning occurred only when feedback probability reflected the subjective difficulty. To optimize learning, training programs need to take into consideration both feedback valence and probability.The research was funded by the Medical Research Council, UK (Grant U135097130; http://www.mrc.ac.uk/), which supported SA, DRM and KM through intramural funding

Optimization search effort over the control landscapes for open quantum systems with Kraus-map evolution

A quantum control landscape is defined as the expectation value of a target observable $\Theta$ as a function of the control variables. In this work control landscapes for open quantum systems governed by Kraus map evolution are analyzed. Kraus maps are used as the controls transforming an initial density matrix $\rho_{\rm i}$ into a final density matrix to maximize the expectation value of the observable $\Theta$. The absence of suboptimal local maxima for the relevant control landscapes is numerically illustrated. The dependence of the optimization search effort is analyzed in terms of the dimension of the system $N$, the initial state $\rho_{\rm i}$, and the target observable $\Theta$. It is found that if the number of nonzero eigenvalues in $\rho_{\rm i}$ remains constant, the search effort does not exhibit any significant dependence on $N$. If $\rho_{\rm i}$ has no zero eigenvalues, then the computational complexity and the required search effort rise with $N$. The dimension of the top manifold (i.e., the set of Kraus operators that maximizes the objective) is found to positively correlate with the optimization search efficiency. Under the assumption of full controllability, incoherent control modelled by Kraus maps is found to be more efficient in reaching the same value of the objective than coherent control modelled by unitary maps. Numerical simulations are also performed for control landscapes with linear constraints on the available Kraus maps, and suboptimal maxima are not revealed for these landscapes.Comment: 29 pages, 8 figure

Invasive non‐native species likely to threaten biodiversity and ecosystems in the Antarctic Peninsula region

The Antarctic is considered to be a pristine environment relative to other regions of the Earth, but it is increasingly vulnerable to invasions by marine, freshwater and terrestrial non‐native species. The Antarctic Peninsula region (APR), which encompasses the Antarctic Peninsula, South Shetland Islands and South Orkney Islands, is by far the most invaded part of the Antarctica continent. The risk of introduction of invasive non‐native species to the APR is likely to increase with predicted increases in the intensity, diversity and distribution of human activities. Parties that are signatories to the Antarctic Treaty have called for regional assessments of non‐native species risk. In response, taxonomic and Antarctic experts undertook a horizon scanning exercise using expert opinion and consensus approaches to identify the species that are likely to present the highest risk to biodiversity and ecosystems within the APR over the next 10 years. One hundred and three species, currently absent in the APR, were identified as relevant for review, with 13 species identified as presenting a high risk of invading the APR. Marine invertebrates dominated the list of highest risk species, with flowering plants and terrestrial invertebrates also represented; however, vertebrate species were thought unlikely to establish in the APR within the 10 year timeframe. We recommend (a) the further development and application of biosecurity measures by all stakeholders active in the APR, including surveillance for species such as those identified during this horizon scanning exercise, and (b) use of this methodology across the other regions of Antarctica. Without the application of appropriate biosecurity measures, rates of introductions and invasions within the APR are likely to increase, resulting in negative consequences for the biodiversity of the whole continent, as introduced species establish and spread further due to climate change and increasing human activity

Mutations in CNNM4 Cause Jalili Syndrome, Consisting of Autosomal-Recessive Cone-Rod Dystrophy and Amelogenesis Imperfecta

The combination of recessively inherited cone-rod dystrophy (CRD) and amelogenesis imperfecta (AI) was first reported by Jalili and Smith in 1988 in a family subsequently linked to a locus on chromosome 2q11, and it has since been reported in a second small family. We have identified five further ethnically diverse families cosegregating CRD and AI. Phenotypic characterization of teeth and visual function in the published and new families reveals a consistent syndrome in all seven families, and all link or are consistent with linkage to 2q11, confirming the existence of a genetically homogenous condition that we now propose to call Jalili syndrome. Using a positional-candidate approach, we have identified mutations in the CNNM4 gene, encoding a putative metal transporter, accounting for the condition in all seven families. Nine mutations are described in all, three missense, three terminations, two large deletions, and a single base insertion. We confirmed expression of Cnnm4 in the neural retina and in ameloblasts in the developing tooth, suggesting a hitherto unknown connection between tooth biomineralization and retinal function. The identification of CNNM4 as the causative gene for Jalili syndrome, characterized by syndromic CRD with AI, has the potential to provide new insights into the roles of metal transport in visual function and biomineralization

Large-scale mapping of human protein–protein interactions by mass spectrometry

Mapping protein–protein interactions is an invaluable tool for understanding protein function. Here, we report the first large-scale study of protein–protein interactions in human cells using a mass spectrometry-based approach. The study maps protein interactions for 338 bait proteins that were selected based on known or suspected disease and functional associations. Large-scale immunoprecipitation of Flag-tagged versions of these proteins followed by LC-ESI-MS/MS analysis resulted in the identification of 24 540 potential protein interactions. False positives and redundant hits were filtered out using empirical criteria and a calculated interaction confidence score, producing a data set of 6463 interactions between 2235 distinct proteins. This data set was further cross-validated using previously published and predicted human protein interactions. In-depth mining of the data set shows that it represents a valuable source of novel protein–protein interactions with relevance to human diseases. In addition, via our preliminary analysis, we report many novel protein interactions and pathway associations

The biogeochemical impact of glacial meltwater from Southwest Greenland

Biogeochemical cycling in high-latitude regions has a disproportionate impact on global nutrient budgets. Here, we introduce a holistic, multi-disciplinary framework for elucidating the influence of glacial meltwaters, shelf currents, and biological production on biogeochemical cycling in high-latitude continental margins, with a focus on the silica cycle. Our findings highlight the impact of significant glacial discharge on nutrient supply to shelf and slope waters, as well as surface and benthic production in these regions, over a range of timescales from days to thousands of years. Whilst biological uptake in fjords and strong diatom activity in coastal waters maintains low dissolved silicon concentrations in surface waters, we find important but spatially heterogeneous additions of particulates into the system, which are transported rapidly away from the shore. We expect the glacially-derived particles – together with biogenic silica tests – to be cycled rapidly through shallow sediments, resulting in a strong benthic flux of dissolved silicon. Entrainment of this benthic silicon into boundary currents may supply an important source of this key nutrient into the Labrador Sea, and is also likely to recirculate back into the deep fjords inshore. This study illustrates how geochemical and oceanographic analyses can be used together to probe further into modern nutrient cycling in this region, as well as the palaeoclimatological approaches to investigating changes in glacial meltwater discharge through time, especially during periods of rapid climatic change in the Late Quaternary

International home economics

The conference was planned to serve the interests of those who wish to work in home economics programs abroad and those who are concerned with the education of international students in the universities and colleges of the United States. Approximately 165 home economists from other states and from foreign countries I including the African and Latin American countries I participated in the conference.https://lib.dr.iastate.edu/card_reports/1026/thumbnail.jp

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Initial antibodies binding to HIV-1 gp41 in acutely infected subjects are polyreactive and highly mutated

Many HIV-1 envelope-reactive antibodies shortly after HIV-1 transmission may arise from crow-reactive memory B cells previously stimulated by non-HIV-1 host or microbial antigen