bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of Mobile Applications for Hospital Discharge Letters
Authors: Maher Bridget , Drachsler Hendrik , Kalz Marco , Hoare Cathal , Sorensen Humphrey , Lezcano Leonardo , Henn Pat , Specht Marcus
Published: January 2014

Handover of patient care is a time of particular risk and it is important that accurate and relevant information is clearly communicated. The hospital discharge letter is an important part of handover. However, the quality of hospital discharge letters is variable and letters frequently omit important information. The Cork Letter-Writing Assessment Scale (CLAS) checklist is an itemized checklist developed to improve the quality of discharge letters. The CLAS checklist, with an inbuilt scoring system, is available as the CLAS mobile application. Mobile applications offer an exciting opportunity for ‘point of practice’ knowledge acquisition and are widely used by medical students. Content quality is integral to the success of educational mobile applications. In a recent study, the CLAS checklist improved the quality (content, structure and clarity) of discharge letters written by medical students. Though retention of these skills into the work-place and effects on patient safety have yet to be demonstrated, the development of standardized electronic discharge letters allows faster and safer transfer of information between healthcare providers and is a welcome advance. Using Near Field Communication for mobile applications to seamlessly transfer discharge letters between devices is another important feature.
Sequential Voronoi Diagram Calculations using Simple Chemical Reactions
Authors: Costello B. P. J. de Lacy , Jahan I. , Adamatzky A.
Published: January 2014

In the authors’ recent paper (de Lacy Costello et al., 2010) the authors described the formation of complex tessellations of the plane arising from the various reactions of metal salts with potassium ferricyanide and ferrocyanide loaded gels. In addition to producing colourful tessellations these reactions are naturally computing generalised Voronoi diagrams of the plane. The reactions reported previously were capable of the calculation of three distinct Voronoi diagrams of the plane. As diffusion coupled with a chemical reaction is responsible for the calculation then this is achieved in parallel. Thus an increase in the complexity of the data input does not utilise additional computational resource. Additional benefits of these chemical reactions are that a permanent record of the Voronoi diagram calculation (in the form of precipitate free bisectors) is achieved, so there is no requirement for further processing to extract the calculation results. Previously it was assumed that the permanence of the results was also a potential drawback which limited reusability. This paper presents new data which shows that sequential Voronoi diagram calculations can be performed on the same chemical substrate. This is dependent on the reactivity of the original reagent and the cross reactivity of the secondary reagent with the primary product. The authors present the results from a number of binary combinations of metal salts on both potassium ferricyanide and potassium ferrocyanide substrates. The authors observe three distinct mechanisms whereby secondary sequential Voronoi diagrams can be calculated. In most cases the result was two interpenetrating permanent Voronoi diagrams. This is interesting from the perspective of mapping the capability of unconventional computing substrates. But also in the study of natural pattern formation per se.
Challenges in Climate Change and Environmental Crisis
Authors: Jafari Mostafa
Published: January 2014

Climate change challenges need to be considered in various dimensions. Aviation industry has multiple impacts on human lives such as impacts on the urban and natural environments. Various dimensions of the issue and its importance have been reported by the IPCC, following a request from the ICAO and the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer in 1999. In this paper different related topics have been investigated. Aviation: Development and Improvement, Climate changes as main environmental crisis, causative source of pollutions: Air pollution (GHGs, aerosol, smoke and particulate, dust), water pollution, biodiversity, hazardous materials, and aeronautical noise. Link between aviation impacts and environmental crisis have been discussed. Different perspectives of the aviation challenge briefly are presented: I- Human dimension, II- Urban environment (local, regional, and global), III- Natural environments (terrestrial, aquatic, and atmospheric) and IV- Birds killed by intervention. In concluding remarks two aspects of the issue, A) benefits, and B) impacts have been considered, and in the end some recommendations have been made on Emissions Trading, Environmental Performance, and Technological Developments.
Applications of Virtual Reality Technologies in Architecture and in Engineering
Authors: Sala Nicoletta
Published: January 2014

Virtual reality (VR) is a technology which permits to create virtual objects and 3D virtual worlds which are hosted on the computer’s memories. It is indispensable in critical simulation, for instance in military training, in surgical operation simulation, in creation of environments which could set off phobias (in psychiatry), or in realization of virtual prototypes, for instance in industrial design. The aim of this paper is to present how VR technologies also find excellent application fields in architecture and in engineering. For instance, in the teaching of the basic concepts, in techniques of graphic rebuilding for the building restoration, in realization of virtual visits inside buildings, and in urban generative processes simulated by computer. Another use of the virtual reality is in the introduction of a new kind of architecture: Virtual Architecture, strongly connected to the Information and Communication Technology (ITC) and to the Internet, and in the virtual prototyping which connects engineering and architecture.
Understanding the Link Between Initial ERP Systems and ERP-Enabled Adoption
Authors: Nwankpa Joseph K. , Roumani Yaman , Brandyberry Alan , Guiffrida Alfred , Hu Michael , Shanker Murali
Published: January 2014

ERP systems have been identified as platform technologies that permit the adoption of subsequent technologies that leverage the information integration created by an ERP system. Although significant research attention has been directed at ERP system adoption, very little attention has been paid to understanding ERP-enabled adoption, that is, adoptions that occur and are facilitated after the initial ERP system. This paper seeks to fill this void. Synthesizing existing works, the authors construct a model that examines the link between initial ERP system and ERP-enabled adoption. The results indicate that initial ERP system factors (Extent of ERP Implementation and Current System Performance) act as antecedences to organizational ease of use and relative advantage of subsequent technologies. Moreover, the authors’ findings implicate that organizational ease of use and relative advantage of subsequent technologies have a positive impact on ERP-enabled adoption. These results have important implications for ERP system evaluation and justification. First, the findings highlight the importance of recognizing the potential additions and inherent benefits created by an initial ERP system. Second, the findings also underscore the importance of considering ERP-enabled adoption of subsequent technologies.
Engineering Security Agreements Against External Insider Threat
Authors: Franqueira Virginia N. L. , van Cleeff André , van Eck Pascal , Wieringa Roel J.
Published: January 2014

Companies are increasingly engaging in complex inter-organisational networks of business and trading partners, service and managed security providers to run their operations. Therefore, it is now common to outsource critical business processes and to completely move IT resources to the custody of third parties. Such extended enterprises create individuals who are neither completely insiders nor outsiders of a company, requiring new solutions to mitigate the security threat they cause. This paper improves the method introduced in Franqueira et al. (2012) for the analysis of such threat to support negotiation of security agreements in B2B contracts. The method, illustrated via a manufacturer-retailer example, has three main ingredients: modelling to scope the analysis and to identify external insider roles, access matrix to obtain need-to-know requirements, and reverse-engineering of security best practices to analyse both pose-threat and enforce-security perspectives of external insider roles. The paper also proposes future research directions to overcome challenges identified.
Towards a Strategic Process Model of Governance for Agile IT Implementation: A Healthcare Information Technology Study in China
Authors: Teoh Say Yen , Chen Xi
Published: January 2014

To remain competitive in the present dynamic environment, ‘governance for agility’ has become a key solution. Past literature paid little attention to understanding how governance for agility, particularly in regard to the delivery of Information Technology (IT) implementation. Using agile organisation and IT-governance theory as lenses to analyse data from a hospital case study, a strategic process model of governance for agility is empirically derived. This model suggests that agile healthcare information technology implementation is achievable via phase-based IT-governance strategies and forms which authorise decision makers to maneuver resources strategically in a dynamic environment. Theoretically, this study contributes to the dearth of empirical understanding of IT governance in the Healthcare IT literature and advances knowledge by making a conceptual distinction through introducing the use of phase-based IT-governance strategies and forms to generate agile organisational capabilities to achieve agile Healthcare IT implementation. The findings serve as a foundation for future research within the information systems (IS) discipline. Practitioners could plan an agile Healthcare IT implementation by referring to the model—a systematic roadmap for governing and strategising hospital resources and capabilities.
Developing Organizational Agility through IT and Supply Chain Capability
Authors: Bi Rui , Davidson Robert , Kam Booi , Smyrnios Kosmas
Published: January 2014

Organizations have increasingly invested money in information technology (IT) in order to improve their agility. It is generally believed that organizations with greater IT investment tend to be more agile to response to environmental changes. However, the issue of whether IT is an enabler or impeder of organizational agility still remains unresolved. Drawing upon resource-based view theory and the literatures of information systems and supply chain management, the authors develop and test a theoretical model that integrates IT capability, supply chain capability and organizational agility. The authors propose that IT capability enables the development of a higher level of supply chain capability which is embedded within inter-firm processes and in turn enhances organizational agility. Structural equation modelling is employed to test their theoretical conceptualization of 310 Australian fast-growth small-to-medium enterprises across different industrial sectors. The results show that IT capability does contribute to firm agility through enhancing inter-firm supply chain processes such as integration, information sharing and coordination. This research highlights the role of IT-enabled intermediated processes and the ways in which IT is used by firms to enhance core business processes.
Investigating Factors Inhibiting e-Government Adoption in Developing Countries
Authors: Kamal Muhammad M. , Hackney Ray , Sarwar Kashif
Published: January 2014

Researchers in the discipline of electronic government (e-Government) have historically presented several factors impeding the adoption and implementation of these systems. This paper is uniquely aimed at investigating the factors inhibiting e-Government adoption in a developing country – Pakistan. The literature indicates that the move towards integrated service provision and transactional e-Government is considered as an immense challenge for developing countries as compared to developed regions. Moreover, the progress towards realising the full potential of e-Government using digital technologies to improve public services and government-citizen engagements has been slower and less effective in the developing countries. Pakistan, over many years, has experienced similar lethargic e-Government growth due to economic and political instability, poor governance and deteriorating government institutions. Thus, the ever increasingly weakening state of government structures in Pakistan calls for the need to deliver end-to-end ‘joined-up’ public services to key stakeholders (i.e. citizens, businesses, government employees and other government agencies). The contribution of this research is twofold – firstly, identifying factors inhibiting e-Government adoption in Pakistan – here the focus is to identify the significant problems of meeting demands which are attributed to several issues within organisational, strategic, technological, political, operational, stakeholders and social structures. Secondly, the authors propose an achievable approach to enacting e-Government enabled delivery of services. The conceptual findings, as noted, are validated through qualitative based research in the context of Pakistan government organisations.
User Continuance Intention Towards Mobile Internet Service: The Case Of WiMAX in Korea
Authors: Kim Hee-Woong , Gupta Sumeet , Jeon Yoon-Seung
Published: January 2014

The usage of mobile Internet service has been on the rise as more people become to use mobile devices. WiMAX, a mobile Internet service, was first commercialized in Korea in 2006. However, after first six months, a number of users discontinued the service and switched to other Internet services. Because customer retention is important for the success of any business, this research examines the factors that affect the continued usage of mobile Internet service. A user of a mobile Internet service is both a user of technology and consumer of services. Therefore, to examine the continued usage of mobile Internet service, the authors combine the value adoption model, representing the service consumer perspective, with the information systems continuance model, representing the technology user perspective. The study is conducted in the context of WiMAX. The data was collected from 200 WiMAX users. The model developed in this study is a unique contribution to theory as it discusses the continued adoption of a commercial information system.
Identification of regulatory genes to improve nitrogen use efficiency
Authors: Guevara David R. , Bi Yong-Mei , Rothstein Steven J.
Published: January 2014

Guevara, D. R., Bi, Y.-M. and Rothstein, S. J. 2014. Identification of regulatory genes to improve nitrogen use efficiency. Can. J. Plant Sci. 94: 1009–1012. Crop production on soils containing sub-optimal levels of nitrogen (N) severely compromises yield potential. The development of crop varieties displaying high N use efficiency (NUE) is necessary in order to optimize N fertilizer use, and reduce the environmental damage caused by the current excessive application of N in agricultural areas. Genome-wide microarray analysis of rice plants grown under N-limiting environments was performed to identify NUE candidate genes. An early nodulin gene, OsENOD93-1, was strongly up-regulated during plant growth under low N. A constitutive Ubiquitin promoter was used to drive the expression of the OsENOD93-1 gene in transgenic plants to determine the importance of OsENOD93-1 for rice NUE. Transgenic rice plants over-expressing the OsENOD93-1 gene achieved ∼23% and 16% more yield and biomass, respectively, compared with wild-type plants when grown under N-limitation conditions. OsENOD93-1-OX transgenic plants accumulated a higher amount of total amino acids in the roots and xylem sap under N stress, suggesting that OsENOD93-1 plays a role in the transportation of amino acids. Taken together, we demonstrate that an effective way to identify NUE gene candidates involves both transcriptional profiling coupled with a transgenic validation approach to improve complex traits such as NUE in important crops.
Efficiency of protein as a nitrogen source for wheat and morphological changes in roots exposed to high protein concentrations
Authors: Rasmussen Jay , Gilroyed Brandon H. , Reuter Tim , Badea Ana , Eudes François , Graf Robert , Laroche André , Kav Nat N. V. , McAllister Tim A.
Published: January 2014

Rasmussen, J., Gilroyed, B. H., Reuter, T., Badea, A., Eudes, F., Graf, R., Laroche, A., Kav, N. N. V. and McAllister, T. A. 2014. Efficiency of protein as a nitrogen source for wheat and morphological changes in roots exposed to high protein concentrations. Can. J. Plant Sci. 94: 603–613. Proteins of animal origin can enter the environment through application of agricultural by-products to arable or pastured land. In this study, wheat (Triticum aestivum cv. AC Andrew) was exposed to treatments with nitrogen (N) supplied as animal protein (bovine serum albumin; BSA), inorganic N or a combination of these sources at different iso-nitrogenous concentrations. Plant growth was assessed by monitoring both wet and dry mass of shoots and data showed that protein treatments did not differ (P>0.05) from controls lacking N. Analysis of N also showed that plants supplied with protein N displayed lower N (1.2–2.4%) concentration as compared with those supplied with inorganic N (up to 12.4%) with N remaining <2.4% even when the supply of protein was increased. Root morphology was altered in plants exposed to protein N concentrations >71 mM, with the development of knob-like outgrowths with unknown function or significance. This study provides evidence that wheat plantlets grown under sterile conditions are unable to utilize BSA as efficiently as NH4NO3 as a N source, but their roots exhibit a morphological response to protein.
Relating germination requirements of timber milkvetch to seral stage in the Interior Douglas-fir zone
Authors: Thompson D. J.
Published: January 2014

Thompson, D. J. 2014. Relating germination requirements of timber milkvetch to seral stage in the Interior Douglas-fir zone. Can. J. Plant Sci. 94: 723–726. Germination of timber milkvetch (Astragalus miser var. serotinus) seeds was studied to determine if it is an early or late seral species. Seeds were collected from a native plant population and those having a dark seed coat were selected. Germination tests were run in the light or dark and under three temperature regimes: low (constant 10°C), high (constant 25°C), and alternating (25°C day and 10°C night). Germination occurred over a protracted period with new germinants up to 90 d at the lowest temperature. Germination was not affected by light. Germination rate was greater at 25°C than 10°C, while fluctuating temperatures (25 and 10°C alternating every 12 h) reduced germination rate to that at the lower temperature. Days to 50% germination was a more sensitive indicator, with the mean for the fluctuating temperatures falling between those continuous to the high and low temperature. Final germination percentage was reduced at 10°C compared with 25°C, but not with fluctuating temperatures. Timber milkvetch seed germination did not respond to light or fluctuating temperatures, adding to a body of evidence that it is a late seral species.
AAC Lacombe field pea
Authors: Bing Deng-Jin , Beauchesne Don , McLaren Debra , Vera Cecil , Gehl David
Published: January 2014

Bing, D., Beauchesne, D., McLaren, D., Vera, C. and Gehl, D. 2014. AAC Lacombe field pea. Can. J. Plant Sci. 94: 805–806. AAC Lacombe is a semi-leafless, yellow cotyledonary field pea (Pisum sativum L.) cultivar developed at Agriculture and Agri-Food Canada Lacombe Research Centre, Lacombe, Alberta, Canada. It is a high-yielding cultivar with excellent standability. AAC Lacombe is resistant to powdery mildew caused by Erysiphe pisi Syd. It has medium maturity and is adapted to all field pea growing regions in western Canada.
On the phytoplankton bloom in coastal waters of southern King George Island (Antarctica) in January 2010: An exceptional feature?
Authors: Schloss I. R. , Wasilowska A. , Dumont D. , Almandoz G. O. , Hernando M. P. , Michaud-Tremblay C.-A. , Saravia L. , Rzepecki M. , Monien P. , Monien D. , Kopczyńska E. E. , Bers A. V. , Ferreyra G. A.
Published: January 2014

Since the early 1990s, phytoplankton has been studied and monitored in Potter Cove (PC) and Admiralty Bay (AB), King George/25 de Mayo Island (KGI), South Shetlands. Phytoplankton biomass is typically low compared to other Antarctic shelf environments, with average spring—summer values below 1 mg chlorophyll a (Chl a) m−3. The physical conditions in the area (reduced irradiance induced by particles originated from the land, intense winds) limit the coastal productivity at KGI, as a result of shallow Sverdrup's critical depths (Zc) and large turbulent mixing depths (Zt). In January 2010 a large phytoplankton bloom with a maximum of around 20 mg Chl a m−3, and monthly averages of 4 (PC) and 6 (AB) mg Chl a m−3, was observed in the area, making it by far the largest recorded bloom over the last 20 yr. Dominant phytoplankton species were the typical bloom‐forming diatoms that are usually found in the western Antarctic Peninsula area. Anomalously cold air temperature and dominant winds from the eastern sector seem to explain adequate light : mixing environment. Local physical conditions were analyzed by means of the relationship between Zc and Zt, and conditions were found adequate for allowing phytoplankton development. However, a multiyear analysis indicates that these conditions may be necessary but not sufficient to guarantee phytoplankton accumulation. The relation between maximum Chl a values and air temperature suggests that bottom‐up control would render such large blooms even less frequent in KGI under the warmer climate expected in the area during the second half of the present century.
Oxygen in the deep Strait of Georgia, 1951–2009: The roles of mixing, deep‐water renewal, and remineralization of organic carbon
Authors: Johannessen Sophia C. , Masson Diane , Macdonald Robie W.
Published: January 2014

The concentration of oxygen in the deep Strait of Georgia has declined at a rate of 0.45–1.3 µmol L−1 yr−1 since 1971 and now seasonally approaches thresholds of biological tolerance. The decline has resulted principally from the increasing hypoxia of upwelled Pacific Ocean water. Local anthropogenic loadings have little potential to reduce bottom water oxygen concentrations. Hypoxic, upwelled water mixes vigorously with surface water in the tidal passages of Haro Strait before entering the deep Strait of Georgia during a series of deep‐water renewal events in late spring and late summer. Remineralization of at least 22 µmol L−1 yr−1, together with diffusive mixing, reduces the bottom water oxygen concentration to a winter minimum of 90–110 µmol L−1. Linear extrapolation of the long‐term trend indicates that parts of the Strait could become episodically hypoxic (< 62.5 µmol L−1; < 1.4 mL L−1) as early as 2042. However, water mass modeling shows that the mixing with surface water in Haro Strait limits the potential of the shelf water to reduce the oxygen concentration in the deep Strait; even should the shelf water become completely anoxic, the concentration of oxygen in bottom waters would level off just above 90 µmol L−1 after 3 yr. Increasing surface water temperature will reduce the solubility of oxygen, but this effect is projected to cause a further decline of only 2.2 µmol L−1 over the next 25 yr. Despite its restricted circulation, the deep Strait of Georgia is less threatened by hypoxia than are many other coastal areas, because of the combination of light‐limited primary production and intense tidal mixing in the approaches, which replenishes the deep‐water oxygen annually.
Pathways of river water to the surface layers of stratified reservoirs
Authors: Cortés A. , Fleenor W. E. , Wells M. G. , de Vicente I. , Rueda F. J.
Published: January 2014

This study uses tracer experiments to characterize the fate of a cold plunging river into a Mediterranean reservoir under different stratification conditions. Three tracer experiments in Lake Béznar, Spain, demonstrate that a significant fraction of the inflow may be quickly entrained into the surface mixed layer (SML), rather than flowing to lower depths. We observe that a fraction (and possibly all) of river inflow entrains into the SML when the density current forms intrusions at the top of the metalimnetic layer. Intrusions near the base of the SML form due to lighter interfacial fluid at the top of the density current, with intermediate properties between river—reservior water when there is sufficient dilution of the cold inflow, and abrupt density changes at the base of the SML. Consequently, a layer of fluid splits from the denser part of the current and intrudes just below the SML, while any remaining fluid flows to lower depths. We parameterize this splitting behavior in terms of the transition Richardson number, Ri12 = Γ × (ρ2 − ρ1)/(ρ0 − ρ1), where ρ0, ρ1, and ρ2 are densities of the inflow, the SML, and the metalimnetic layer underneath, respectively; and Γ is the total dilution through the plunge zone and subsequent entrainment. Splitting occurs when Ri12 ≥ 1, consistent with previous laboratory experiments. We use this theory to predict the seasonal fate of river water during the stratification of Lake Béznar and identify the conditions that favor the formation of intrusions near the base of the SML.
Oxygen photolysis in the Mauritanian upwelling: Implications for net community production
Authors: Kitidis Vassilis , Tilstone Gavin H. , Serret Pablo , Smyth Timothy J. , Torres Ricardo , Robinson Carol
Published: January 2014

We carried out 16 photochemical experiments of filtered surface water in a custom‐built solar simulator and concomitant measurements of in vitro gross primary production (GPP) and respiration (R) in the Mauritanian upwelling during a Lagrangian study following three sulfur hexafluoride—labeled patches of upwelled water (P1 to P3). Oxygen photolysis rates were correlated with the absorbance of chromophoric dissolved organic matter (CDOM) at 300 nm, suggesting first‐order kinetics with respect to CDOM. An exponential fit was used to calculate the apparent quantum yield (AQY) for oxygen photolysis, giving an average AQY of 0.00053 µmol O2 (mole photons m−2 s−1)−1 at 280 nm and slope of 0.0012 nm−1. Modeled photochemical oxygen demand (POD) at the surface (3–16 mmol m−3 d−1) occasionally exceeded R and was dominated by ultraviolet radiation (71–79%). Euphotic‐layer integrated GPP decreased with time during both P‐1 and P‐3, whereas R remained relatively constant and POD increased during P‐1 and decreased during P‐3. On Day 4 of P‐3, GPP and POD maxima coincided with high CDOM absorbance, suggesting “new” CDOM production. Omitting POD may lead to an underestimation of net community production (NCP), both through in vitro and geochemical methods (here by 2–22%). We propose that oxygen‐based NCP estimates should be revised upward. For the Mauritanian upwelling, the POD‐corrected NCP was strongly correlated with standard NCP with a slope of 1.0066 ± 0.0244 and intercept of 46.51 ± 13.15 mmol m−2 d−1.
Ammonium cycling in the rocky intertidal: Remineralization, removal, and retention
Authors: Pather Santhiska , Pfister Catherine A. , Post David M. , Altabet Mark A.
Published: January 2014

Rocky intertidal productivity is traditionally thought to be sustained almost solely by upwelled nitrate with remineralized forms of minor importance. Using tidepools as natural experimental mesocosms, we conducted 15N‐tracer experiments to test whether ammonium remineralized within the rocky intertidal is also a significant source of fixed N to localized ecosystem production. Comparison of tidepools with and without the dominant bivalve Mytilus californianus allowed consideration of its role in NH+4 cycling. Closed water‐incubation bottles were used to investigate the contribution of suspended microbes to NH+4 cycling. Tidepools with mussels had both greater NH+4 remineralization (two times) and NH+4 removal as compared with those without, with daytime rates greater than nighttime rates. Incorporation of NH+4 tracer by particulate organic matter and macroalgae, and the persistence of this signal in tidepools for several days following the experiment, showed retention of autochthonous NH+4 in the system. Remineralization rates were tightly correlated to removal rates when compared over all treatments and experiments, but NH+4 remineralization was significantly greater than removal, suggesting a surplus available to nearshore primary producers.
Nutrient loading and meteorological conditions explain interannual variability of hypoxia in Chesapeake Bay
Authors: Zhou Yuntao , Scavia Donald , Michalak Anna M.
Published: January 2014

We use geostatistical universal kriging and conditional realizations to provide the first quantitative estimates, with robust estimates of uncertainties, of the seasonal and interannual variability in hypoxic volume in Chesapeake Bay, covering early April to late October for 1985 to 2010, and explore factors controlling that variability. Results show that the time when the hypoxic volume reaches its maximum has moved from late to early July over the examined period, but that there is no trend in the seasonal‐maximum hypoxic volume itself. No significant trend was found in the timing of onset of hypoxia, but the end of the hypoxic period has moved from October to September. Including nutrient loading from the Rappahannock River in addition to the Susquehanna and Potomac Rivers is found to be beneficial for explaining the interannual variability of hypoxia. Overall, January to May total nitrogen loads from these three rivers, April to August southwesterly and northeasterly winds, and April and May precipitation explain > 85% of the seasonally averaged interannual variability in hypoxic volumes. Southwesterly winds affect hypoxia by increasing vertical stratification, while precipitation likely acts as a surrogate for nonpoint sources of nitrogen downstream from monitoring stations. The relative contribution of nutrient loading to the overall interannual variability suggests that 28–35% reductions in monitored nutrient loads may not be sufficient to achieve a corresponding reduction in hypoxic conditions as had been suggested in previous studies, at least in the short term.
Dissolved cadmium in the Southern Ocean: Distribution, speciation, and relation to phosphate
Authors: Baars Oliver , Abouchami Wafa , Galer Stephen J. G. , Boye Marie , Croot Peter L.
Published: January 2014

We report isotope dilution analyses of dissolved cadmium (Cd) and electrochemical Cd speciation measurements in the Atlantic sector of the Southern Ocean. Bioavailable inorganic Cd is > 100 times higher in near‐surface waters south of the Polar Front compared to the Subantarctic Zone because of upwelling and reduced complexation by organic Cd ligands. To trace local changes in the relation between Cd and P, we examine the deviations from a linear deep‐water Cd vs. P relation (Cd*), and find that changes in Cd* coincide with the position of frontal systems and covary with primary productivity and total dissolved Mn and Fe concentrations. These covariations agree with potential local changes in phytoplankton Cd uptake rates, resulting from differences in the availability of Cd, Zn, Mn, and Fe. A band of negative Cd* values is associated with formation of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW). In contrast to SAMW, which may export low Cd : P ratios from the Southern Ocean, the Cd : P ratios in AAIW increase by mixing with underlying Upper Circumpolar Deep Water before being exported from the Southern Ocean. Deep waters show constant Cd : P ratios, and both elements behave conservatively with end‐member mixing between deep waters of the Weddell Gyre, the Antarctic Circumpolar Current, and inflowing North Atlantic Deep Water. Overall, our results support the hypothesis that the kink in the global Cd vs. P relation is largely caused by high Cd : P uptake ratios in the trace‐nutrient—limited Southern Ocean.
Morphological and genetic variability in an alien invasive mussel across an environmental gradient in South America
Authors: Paolucci Esteban M. , Sardiña Paula , Sylvester Francisco , Perepelizin Pablo V. , Zhan Aibin , Ghabooli Sara , Cristescu Melania E. , Oliveira Marcia D. , MacIsaac Hugh J.
Published: January 2014

Adaptation is an essential step in the establishment and spread of alien species in new environments, with phenotypic plasticity or genetic variability often contributing to this success. The golden mussel Limnoperna fortunei is a biofouling mollusc native to Southeast Asia that was introduced to South America near the Río de la Plata estuary, Argentina, though the species has subsequently spread more than 2000 km upstream. We analyzed morphological and genetic variation in 24 introduced populations of L. fortunei across its South American range. Relative gill area and shell morphology differed significantly, even among geographically proximate populations. Differences in relative gill area were especially marked across the species' range and were negatively correlated with total suspended solids. Whereas mean gill cilia length, filament width, and interfilamental ciliary junction distance did not differ significantly among populations, mean gill cilia density was significantly lower in populations from areas with high suspended solids. Conversely, morphological differences were not related to the number of haplotypes, haplotype diversity, or nucleotide diversity, based upon analyses of the mitochondrial cytochrome c oxidase subunit 1 gene. Our results indicate that introduced populations of golden mussels in South America exhibit pronounced morphological variation in shell and gill metrics that appear to result from developmental plasticity in relation to total suspended sediments, as has been observed in other mussel species. These adaptations may have facilitated spread of this species to a wide range of habitats.
Two hundred fifty years of aerosols and climate: the end of the age of aerosols
Authors: Smith S. J. , Bond T. C.
Published: January 2014

Abstract. Carbonaceous and sulfur aerosols have a substantial global and regional influence on climate, resulting in a net cooling to date, in addition to their impact on health and ecosystems. The magnitude of this influence has changed substantially over the past and is expected to continue to change into the future. An integrated picture of the changing climatic influence of black carbon, organic carbon and sulfate over the period 1850 through 2100, focusing on uncertainty, is presented using updated historical inventories and a coordinated set of emission projections. We describe, in detail, the aerosol emissions from the RCP4.5 scenario and its associated reference scenario. While aerosols have had a substantial impact on climate over the past century, we show that, by the end of the 21st century, aerosols will likely be only a minor contributor to radiative forcing due to increases in greenhouse gas forcing and a net global decrease in pollutant emissions. This outcome is even more certain under a successful implementation of a policy to limit greenhouse gas emissions as low-carbon energy technologies that do not emit appreciable aerosol or SO2 are deployed.
Pressure dependent isotopic fractionation in the photolysis of formaldehyde-d2
Authors: Nilsson E. J. K. , Schmidt J. A. , Johnson M. S.
Published: January 2014

Abstract. The isotope effects in formaldehyde photolysis are the key link between the δD of methane emissions and the δD of atmospheric in situ hydrogen production. A few recent studies have suggested that a pressure dependence in the isotopic fractionation can partly explain enrichment of deuterium with altitude in the atmosphere. The mechanism and the extent of this pressure dependency is, however, not adequately described. In the present work D2CO and H2CO were photolyzed in a static reaction chamber at bath gas pressures of 50, 200, 400, 600 and 1000 mbar; these experiments compliment and extend our earlier work with HDCO vs. H2CO. The UV lamps used for photolysis emit light at wavelengths that primarily dissociate formaldehyde into molecular products, CO and H2 or D2. The isotope effect k(H2CO)/k(D2CO) = 3.16 ± 0.03 at 1000 mbar is in good agreement with results from previous studies. Similarly to what was previously shown for k(H2CO)/k(HDCO), the isotope effect decreased as pressure decreased. In addition, a model was constructed using RRKM theory to calculate the lifetime of excited formaldehyde on the S0 surface, to investigate its role in the observed pressure dependent photolytic fractionation of deuterium. The model shows that part of the fractionation is a result of competition between the isotopologue dependent rates of unimolecular dissociation and collisional relaxation. We suggest that the remaining fractionation is due to isotope effects in the rate of the non-radiative transition from S1 to S0, which are not considered in the present model.
The transport of atmospheric NOx and HNO3 over Cape Town
Authors: Abiodun B. J. , Ojumu A. M. , Jenner S. , Ojumu T. V.
Published: January 2014

Abstract. Cape Town, the most popular tourist city in Africa, usually experiences air pollution with unpleasant odour in winter. Previous studies have associated the pollution with local emission of pollutants within the city. The present study examines the transport of atmospheric pollutants (NOx and HNO3) over South Africa and shows how the transport of pollutants from the Mpumalanga Highveld, a major South African industrial area, may contribute to the pollution in Cape Town. The study analysed observation data (2001–2008) from the Cape Town air-quality network and simulation data (2001–2004) from a regional climate model (RegCM) over southern Africa. The simulation accounts for the influence of complex topography, atmospheric conditions, and atmospheric chemistry on emission and transport of pollutants over southern Africa. Flux budget analysis was used to examine whether Cape Town is a source or sink for NOx and HNO3 during the extreme pollution events. The results show that extreme pollution events in Cape Town are associated with the lower level (surface – 850 hPa) transport of NOx from the Mpumalanga Highveld to Cape Town, and with a tongue of high concentration of HNO3 that extends from the Mpumalanga Highveld to Cape Town along the south coast of South Africa. The prevailing atmospheric conditions during the extreme pollution events feature an upper-level (700 hPa) anticyclone over South Africa and a lower-level col over Cape Town. The anticyclone induces a strong subsidence motion, which prevents vertical mixing of the pollutants and caps high concentration of pollutants close to the surface as they are transported from the Mpumalanga Highveld toward Cape Town. The col accumulates the pollutants over the city. This study shows that Cape Town can be a sink for the NOx and HNO3 during extreme pollution events and suggests that the accumulation of pollutants transported from other areas (e.g. the Mpumalanga Highveld) may contribute to the air pollution in Cape Town.
On the consistency between global and regional methane emissions inferred from SCIAMACHY, TANSO-FTS, IASI and surface measurements
Authors: Cressot C. , Chevallier F. , Bousquet P. , Crevoisier C. , Dlugokencky E. J. , Fortems-Cheiney A. , Frankenberg C. , Parker R. , Pison I. , Scheepmaker R. A. , Montzka S. A. , Krummel P. B. , Steele L. P. , Langenfelds R. L.
Published: January 2014

Abstract. Satellite retrievals of methane weighted atmospheric columns are assimilated within a Bayesian inversion system to infer the global and regional methane emissions and sinks for the period August 2009 to July 2010. Inversions are independently computed from three different space-borne observing systems and one surface observing system under several hypotheses for prior-flux and observation errors. Posterior methane emissions are compared and evaluated against surface mole fraction observations via a chemistry-transport model. Apart from SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY), the simulations agree fairly well with the surface mole fractions. The most consistent configurations of this study using TANSO-FTS (Thermal And Near infrared Sensor for carbon Observation – Fourier Transform Spectrometer), IASI (Infrared Atmospheric Sounding Interferometer) or surface measurements induce posterior methane global emissions of, respectively, 565 ± 21 Tg yr−1, 549 ± 36 Tg yr−1 and 538 ± 15 Tg yr−1 over the one-year period August 2009–July 2010. This consistency between the satellite retrievals (apart from SCIAMACHY) and independent surface measurements is promising for future improvement of CH4 emission estimates by atmospheric inversions.
Overview of the Manitou Experimental Forest Observatory: site description and selected science results from 2008–2013
Authors: Ortega J. , Turnipseed A. , Guenther A. B. , Karl T. G. , Day D. A. , Gochis D. , Huffman J. A. , Prenni A. J. , Levin E. J. T. , Kreidenweis S. M. , DeMott P. J. , Tobo Y. , Patton E. G. , Hodzic A. , Cui Y. , Harley P. C. , Hornbrook R. H. , Apel E. C. , Monson R. K. , Eller A. S. D. , Greenberg J. P. , Barth M. , Campuzano-Jost P. , Palm B. B. , Jimenez J. L. , Aiken A. C. , Dubey M. K. , Geron C. , Offenberg J. , Ryan M. G. , Fornwalt P. J. , Pryor S. C. , Keutsch F. N. , DiGangi J. P. , Chan A. W. H. , Goldstein A. H. , Wolfe G. M. , Kim S. , Kaser L. , Schnitzhofer R. , Hansel A. , Cantrell C. A. , Mauldin III R. L. , Smith J. N.
Published: January 2014

Abstract. The Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen (BEACHON) project seeks to understand the feedbacks and inter-relationships between hydrology, biogenic emissions, carbon assimilation, aerosol properties, clouds and associated feedbacks within water-limited ecosystems. The Manitou Experimental Forest Observatory (MEFO) was established in 2008 by the National Center for Atmospheric Research to address many of the BEACHON research objectives, and it now provides a fixed field site with significant infrastructure. MEFO is a mountainous, semi-arid ponderosa pine-dominated forest site that is normally dominated by clean continental air, but is periodically influenced by anthropogenic sources from Colorado Front Range cities. This article summarizes the past and ongoing research activities at the site, and highlights some of the significant findings that have resulted from these measurements. These activities include: – soil property measurements, – hydrological studies, – measurements of high-frequency turbulence parameters, – eddy covariance flux measurements of water, energy, aerosols and carbon dioxide through the canopy, – biogenic and anthropogenic volatile organic compound emissions and their influence on regional atmospheric chemistry, – aerosol number and mass distributions, – chemical speciation of aerosol particles, – characterization of ice and cloud condensation nuclei, – trace gas measurements, and – model simulations using coupled chemistry and meteorology. In addition to various long-term continuous measurement, three focused measurement campaigns with state-of-the-art instrumentation have taken place since the site was established, and two of these are the subjects of this special issue: BEACHON-ROCS (Rocky Mountain Organic Carbon Study, 2010) and BEACHON-RoMBAS (Rocky Mountain Biogenic Aerosol Study, 2011).
Limited response of peatland CH4 emissions to abrupt Atlantic Ocean circulation changes in glacial climates
Authors: Hopcroft P. O. , Valdes P. J. , Wania R. , Beerling D. J.
Published: January 2014

Abstract. Ice-core records show that abrupt Dansgaard–Oeschger (D–O) climatic warming events of the last glacial period were accompanied by large increases in the atmospheric CH4 concentration (up to 200 ppbv). These abrupt changes are generally regarded as arising from the effects of changes in the Atlantic Ocean meridional overturning circulation and the resultant climatic impact on natural CH4 sources, in particular wetlands. We use two different ecosystem models of wetland CH4 emissions to simulate northern CH4 sources forced with coupled general circulation model simulations of five different time periods during the last glacial to investigate the potential influence of abrupt ocean circulation changes on atmospheric CH4 levels during D–O events. The simulated warming over Greenland of 7–9 °C in the different time periods is at the lower end of the range of 11–15 °C derived from ice cores, but is associated with strong impacts on the hydrological cycle, especially over the North Atlantic and Europe during winter. We find that although the sensitivity of CH4 emissions to the imposed climate varies significantly between the two ecosystem emissions models, the model simulations do not reproduce sufficient emission changes to satisfy ice-core observations of CH4 increases during abrupt events. The inclusion of permafrost physics and peatland carbon cycling in one model (LPJ-WHyMe) increases the climatic sensitivity of CH44 emissions relative to the Sheffield Dynamic Global Vegetation Model (SDGVM) model, which does not incorporate these processes. For equilibrium conditions this additional sensitivity is mostly due to differences in carbon cycle processes, whilst the increased sensitivity to the imposed abrupt warmings is also partly due to the effects of freezing on soil thermodynamics. These results suggest that alternative scenarios of climatic change could be required to explain the abrupt glacial CH4 variations, perhaps with a more dominant role for tropical wetland CH4 sources.