Precise atmospheric oxygen measurements with a paramagnetic oxygen analyzer

A methodology has been developed for making continuous, high-precision measurements of atmospheric oxygen concentrations by modifying a commercially available paramagnetic oxygen analyzer. Incorporating several design improvements, an effective precision of 0.2 ppm O-2 from repeated measurements over a 1-hour interval was achieved. This is sufficient to detect background changes in atmospheric O-2 to a level that constrains various aspects of the global carbon cycle. The analyzer was used to measure atmospheric O-2 in a semicontinuous fashion from air sampled from the end of Scripps Pier, La Jolla, California, and data from a 1-week period in August 1996 are shown. The data exhibit strongly anticorrelated changes in O-2 and CO2 caused by local or regional combustion of fossil fuels. During periods of steady background CO2 concentrations, however, we see additional variability in O-2 concentrations, clearly not due to local combustion and presumably due to oceanic sources or sinks of O-2. This variability suggests that in contrast to CO2, higher O-2 sampling rates, such as those provided by continuous measurement programs, may be necessary to define an atmospheric O-2 background and thus aid in validating and interpreting other O-2 data from flask sampling programs. Our results have also demonstrated that this paramagnetic analyzer and gas handling design is well suited for making continuous measurements of atmospheric O-2 and is suitable for placement at remote background air monitoring sites

A feasibility study of implementing an Ammonia Economy

This thesis reports the results of a feasibility study performed on the concept of an Ammonia Economy, which treats ammonia as an alternative fuel and energy storage mechanism. As part of the Ammonia Economy, costs for production, storage, and transportation of this alternative fuel are also presented. The cost of hydrogen, which is the main feedstock for ammonia production, was first determined for both fossil-fuel and alternative energy sources. Capital costs and operating parameters of an ammonia synthesis plant were then used in an economic model to calculate the cost of ammonia from energy sources that included natural gas, coal, nuclear, ocean thermal energy conversion (OTEC), wind, solar, and biomass. The energy use and cost for both hydrogen and ammonia fuels was then compared for fuel storage and transportation. The results showed that the lowest cost ammonia source is coal with a production cost of 147-432 $/t, or a gasoline equivalent of 0.96-2.83$/gal. Natural gas and OTEC also provided low costs of less than 689 $/t, or a gasoline equivalent of 4.51$/gal. Other alternative ammonia sources were more expensive, however, they may become economical as fossil fuel costs increase and technological advances improve the alternative fuel technology. The storage analysis of ammonia and hydrogen showed that the ammonia storage system is 93.6% efficient when the ammonia synthesis energy is included in the calculation, which was calculated by dividing the chemical energy stored by the chemical and electrical energy added to the storage vessel. In comparison, hydrogen is only 76.9% efficient. Ammonia also required nearly five times less energy for low temperature storage than hydrogen. In addition, ammonia has a storage cost advantage over hydrogen with an estimated cost for 182 days of storage to be 14.83 $/kg-H2 and 0.51$/kg-H2, respectively. Comparing the transportation of the two fuels showed that ammonia is more efficient and less expensive than hydrogen to transport in a pipeline. Specifically, the efficiency for transporting the fuel 1,610 km and delivering it at fueling pressure is 93.4% and 86.9% for ammonia and hydrogen, respectively. The ammonia calculation also includes the losses involved with ammonia synthesis from a hydrogen source. Pipeline transportation costs are estimated to be 0.70-3.22 $/kg for hydrogen, and 0.0344$/kg for ammonia. The ammonia delivery cost in hydrogen terms is 0.194 $/kg-H2, which makes hydrogen at least three times more costly to transport than ammonia

Prediction of children\u27s school readiness by parent and teacher reports and individual testing

The purpose of this study was to develop a comprehensive screening instrument to assess the competencies of young children as they enter kindergarten. A broad range of intellectual, social-emotional, and physical characteristics were evaluated through parental reporting, teacher rating, and direct testing of the children. Each of the three data sources proved to be valuable assets to the screening process. Parents contributed to the screening battery by significantly predicting the success of their children in kindergarten and by rating their children on various competency areas. In addition, such demographic variables as parents\u27 education significantly predicted students\u27 school success;The results of the present study also confirmed previous research demonstrating the effectiveness of teachers\u27 ratings in predicting school success. In a very short period of time (one to four days), the teachers were able to assess a child\u27s academic competency and readiness for the school experience;Direct testing using the Worthing Early Screening Test (WEST), which was developed for the study, complemented the other data sources in predicting concurrent achievement (measured by the Kaufman Assessment Battery for Children - Achievement Scale) and kindergarten success (assessed by the kindergarten teachers\u27 ratings). As hypothesized, the ability to recognize and segment the component sounds of words was an important indicator of early academic achievement. Skills such as counting, short-term memory, and drawing a person were also significant predictors of standardized achievement measures and the teachers\u27 ratings

Risk of postoperative pulmonary complications in adult surgical patients with metabolic syndrome: a systematic review and meta-analysis protocol

Background: Metabolic syndrome (MetS) is defined as an accumulation of risk factors that include chronic hypertension, dyslipidaemia, insulin resistance and obesity and leads to an increased risk for diabetes, cardiovascular disease and stroke. MetS is widespread and estimated to affect up to a quarter of the global population. Patients with MetS who undergo surgery are associated with an increased risk of postoperative complications when compared with patients with a non-MetS profile. An emerging body of literature points to MetS being associated with a greater risk of postoperative pulmonary complications (PPC) in the surgical patient. PPC are associated with increased postoperative morbidity and mortality, Intensive care unit (ICU) admission, length of stay (ICU and hospital), health care costs, resource usage, unplanned re-intubation and prolonged ventilatory time. Methods/design: We will search for relevant studies in the following electronic bibliographic databases: EMBASE, MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Scopus as well as scan the reference lists of included studies for potential additional literature. Two authors will independently screen titles and abstracts to identify potentially relevant studies for inclusion based on predefined inclusion and exclusion criteria. The Cochrane Collaboration Review Manager (Review Manager 5) statistical software will be used to conduct this systematic review and meta-analysis and generate forest plots to demonstrate comparison of findings across studies included for meta analysis. Subgroup and sensitivity analysis will be performed to assess the heterogeneity of included studies. A descriptive synthesis of the statistical data will be provided to summarise the results and findings of the systematic review and meta-analysis. Discussion: This review will be the first to report and summarise the risk for and incidence of PPC in adult patients with MetS undergoing surgery across a range of surgical specialities. The results have the potential to inform the development of evidenced-based interventions to improve the management of PPC in the surgical patient with MetS. Findings from this systematic review and meta-analysis will inform a subsequent Delphi study on priorities and responses to PPC in patients with MetS. We will also disseminate our results through publication in scientific peerreviewed journals, conference presentations and promotion throughout our network of surgical safety champions in clinical settings

Visual consciousness tracked with direct intracranial recording from early visual cortex in humans

A fundamental question in cognitive neuroscience is how neuronal representations are related to conscious experience.
Two key questions are: where in the brain such representations are located, and at what point in time they correlate with conscious experience. In line with this issue, a hotly debated question is whether primary visual cortex (V1) contributes to visual consciousness, or whether this depends only on higher-order cortices. Here we investigated this issue by recording directly from early visual cortex in two neurosurgical patients undergoing epilepsy monitoring with intracranial electrocorticogram (ECoG) electrodes that covered early visual cortices, including the dorsal and ventral banks of the calcarine sulcus. We used Continuous Flash Suppression (CFS)to investigate the time course of when ‘invisible’ stimuli broke interocular suppression. Participants were asked to watch faces presented under CFS, to push a button when they started to see any part of the face, and then to indicate its spatial location. This occurred over several seconds. During the task performance we recorded intracranial ECoG at high spatiotemporal resolution from all contacts in parallel. We used multivariate decoding techniques and found that the location of the invisible face stimulus became decodable from neuronal activity 1.8 sec before the subject’s button press. Counter-intuitively, the same cortical sites from which we were able to decode this predictive signal showed a decrease in activity immediately prior to the transition from invisibility to visibility. Furthermore, we observed an increase in coherence among widely separated electrodes during the invisible epoch, which collapsed to a focal ensemble when the stimulus became visible. These results suggest that diffuse coherent representation is insufficient for visual awareness and that locally specialized patterns of activation may be key to consciousness. Our findings are consistent with one recently proposed framework for understanding consciousness utilizing information integration theory (Tononi, 2008)

Generating Effective Recommendations Using Viewing-Time Weighted Preferences for Attributes

Recommender systems are an increasingly important technology and researchers have recently argued for incorporating different kinds of data to improve recommendation quality. This paper presents a novel approach to generating recommendations and evaluates its effectiveness. First, we review evidence that item viewing time can reveal user preferences for items. Second, we model item preference as a weighted function of preferences for item attributes. We then propose a method for generating recommendations based on these two propositions. The results of a laboratory evaluation show that the proposed approach generated estimated item ratings consistent with explicit item ratings and assigned high ratings to products that reflect revealed preferences of users. We conclude by discussing implications and identifying areas for future research

The Solomon Islands: An Experiment in Decentralization

28 cmBibliography: p. 160-16

Cross-Border Arbitrage And Free Trade

The following study presents a theory of cross-border arbitrage by consumers.  Competitive forces should explain how equilibrium prices would be set on each side of a border. Various trading partners have ratified numerous free-trade pacts. There is a need to investigate the success or failure of these agreements.  Because of the many non-tariff trade barriers, it is sometimes difficult to construct meaningful tests of the free-trade issues for products on an individualized basis.  Our comprehensive model of cross-border price variation develops an appropriate test.  A series of hypotheses on geographical arbitrage are presented. We also explain why some products may have larger price differences than others based on price sensitive arbitrage.  Our model may be used to measure the likelihood of undermining influences to free trade from any non-tariff barriers that continue to plague relations between trading partners.