bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Metrics and a Complexity Scale for the Topology of Assembly Supply Chains
Authors: Modrak Vladimir , Marton David
Published: October 2013

In this paper, we present a methodological framework for conceptual modeling of assembly supply chain (ASC) networks. Models of such ASC networks are divided into classes on the basis of the numbers of initial suppliers. We provide a brief overview of select literature on the topic of structural complexity in assembly systems. Subsequently, the so called Vertex degree index for measuring a structural complexity of ASC networks is applied. This measure, which is based on the Shannon entropy, is well suited for the given purpose. Finally, we outline a generic model of quantitative complexity scale for ASC Networks.
Optimal Conditions for Fast Charging and Long Cycling Stability of Silicon Microwire Anodes for Lithium Ion Batteries, and Comparison with the Performance of Other Si Anode Concepts
Authors: Quiroga-González Enrique , Carstensen Jürgen , Föll Helmut
Published: October 2013

Cycling tests under various conditions have been performed for lithium ion battery anodes made from free-standing silicon microwires embedded at one end in a copper current collector. Optimum charging/discharging conditions have been found for which the anode shows negligible fading (< 0.001%) over 80 cycles; an outstanding result for this kind of anodes. Several performance parameters of the anode have been compared to the ones of other Si anode concepts, showing that especially the capacity as well as the rates of charge flow per nominal area of anode are the highest for the present anode. With regard to applications, the specific parameters per area are more important than the specific gravimetric parameters like the gravimetric capacity, which is good for comparing the capacity between materials but not enough for comparing between anodes.
Design and Development of a Low-Cost Optical Current Sensor
Authors: Zubia Joseba , Casado Luciano , Aldabaldetreku Gotzon , Montero Alfonso , Zubia Eneko , Durana Gaizka
Published: October 2013

In this paper we demonstrate the design of a low-cost optical current sensor. The sensor principle is the Faraday rotation of a light beam through a magneto-optical material, SF2, when a magnetic field is present. The prototype has a high sensitivity and a high linearity for currents ranging from 0 up to 800 A. The error of the optical fibre sensor is smaller than 1% for electric currents over 175 A.
Aptamers as Theranostic Agents: Modifications, Serum Stability and Functionalisation
Authors: Shigdar Sarah , Macdonald Joanna , O'Connor Michael , Wang Tao , Xiang Dongxi , Al.Shamaileh Hadi , Qiao Liang , Wei Ming , Zhou Shu-Feng , Zhu Yimin , Kong Lingxue , Bhattacharya Santanu , Li ChunGuang , Duan Wei
Published: October 2013

Aptamers, and the selection process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX) used to generate them, were first described more than twenty years ago. Since then, there have been numerous modifications to the selection procedures. This review discusses the use of modified bases as a means of enhancing serum stability and producing effective therapeutic tools, as well as functionalising these nucleic acids to be used as potential diagnostic agents.
Phylogenetic relationships among the North American cleomoids (Cleomaceae): A test of Iltis's reduction series
Authors: Riser James P. , Cardinal‐McTeague Warren M. , Hall Jocelyn C. , Hahn William J. , Sytsma Kenneth J. , Roalson Eric H.
Published: October 2013

• Premise of Study: A monophyletic group composed of five genera of the Cleomaceae represents an intriguing lineage with outstanding taxonomic and evolutionary questions. Generic boundaries are poorly defined, and historical hypotheses regarding the evolution of fruit type and phylogenetic relationships provide testable questions. This is the first detailed phylogenetic investigation of all 22 species in this group. We use this phylogenetic framework to assess generic monophyly and test Iltis's evolutionary “reduction series” hypothesis regarding phylogeny and fruit type/seed number.

• Methods: Maximum likelihood and Bayesian analyses of four plastid intergenic spacer region sequences (rpl32‐trnL, trnQ‐rps16, ycf1‐rps15, and psbA‐trnH) and one nuclear (ITS) region were used to reconstruct phylogenetic relationships among the NA cleomoid species. Stochastic mapping and ancestral‐state reconstruction were used to study the evolution of fruit type.

• Key Results: Both analyses recovered nearly identical phylogenies. Three of the currently recognized genera (Wislizenia, Carsonia, and Oxystylis) are monophyletic while two (Cleomella and Peritoma) are para‐ or polyphyletic. There was a single origin of the two‐seeded schizocarp in the ancestor of the Oxystylis–Wislizenia clade and a secondary derivation of elongated capsule‐type fruits in Peritoma from a truncated capsule state in Cleomella.

• Conclusions: Our well‐resolved phylogeny supports most of the current species circumscriptions but not current generic circumscriptions. Additionally, our results are inconsistent with Iltis's hypothesis of species with elongated many‐seed fruits giving rise to species with truncated few‐seeded fruits. Instead, we find support for the reversion to elongated multiseeded fruits from a truncate few‐seeded ancestor in Peritoma.
Interannual Consistency of Gross Energy in Red Oak Acorns
Authors: Leach Alan G. , Kaminski Richard M. , Straub Jacob N. , Ezell Andrew W. , Hawkins Tracy S. , Leininger Theodor D.
Published: October 2013

Red oak Quercus spp., Subgenus Erythrobalanus acorns are forage for mallards Anas platyrhyncos, wood ducks Aix sponsa, and other wildlife that use bottomland hardwood forests in the southeastern United States. However, annual variation in true metabolizable energy from acorns would affect carrying-capacity estimates of bottomland hardwood forests for wintering ducks. Because gross energy and true metabolizable energy are strongly positively correlated and gross energy is easier to measure than true metabolizable energy, we used gross energy as a surrogate for true metabolizable energy. We measured gross energy of six species of red oak acorns in autumns 2008 and 2009. Within species, mean gross energy of these acorns varied less than 2% between years. The small interannual variation in gross energy of red oak acorns found in this study would have negligible effect on estimates of carrying capacity of bottomland hardwood forests for wintering ducks and other wildlife.
Time and the Working Online Learner
Authors: McNeill Bill
Published: October 2013

This chapter explores the issues surrounding the time use of the internationally located postgraduate distance learner who combines study with a home life and employment. It considers the nature of these students as distinct from other students within higher education and the factors that combine to have an impact on their available time for study. Researching time is challenging, and this chapter considers the techniques used in time use studies to build a holistic view of students’ choices regarding the duration and timing of their everyday activities. These techniques are applied in an investigation of a cohort of students to reveal evidence of their daily time use and decision making that have an impact on effective course design. It summarises apparent trends in time use and pays particular attention to students’ use of technology and their engagement with online activities. Throughout, the chapter emphasises time as the critical factor in the successful delivery of contemporary online studies.
Temporal Flexibility in Online University Courses in Spain and Australia
Authors: Barberà Elena , Clarà Marc , Danaher Patrick A. , van Rensburg Henriette
Published: October 2013

Temporal flexibility in learning is one of the main promises and advantages of online learning, as well as one of its most important characteristics. This advantage has been widely exploited by institutions, which offer several degrees online or constitute themselves fully online. Although it is clear that online university courses are able to be more flexible in time than face-to-face courses, it is also true that as formal educational institutions with accreditation responsibilities universities face some time constraints that prevent them from being absolutely flexible. In this chapter, the authors present a study to assess the levels of time flexibility of online courses in two universities in Spain and Australia. To do so, they administrated a Likert-scale questionnaire to 413 students at both universities to assess seven items of time flexibility. The results suggest that in both universities some items of time flexibility are quite high but other items are still low. The authors then discuss these results from the point of view of the nature of higher education institutions and their current role in society.
Temporal Considerations in Analyzing and Designing Online Discussions in Education
Authors: Wise Alyssa Friend , Zhao Yuting , Hausknecht Simone , Chiu Ming Ming
Published: October 2013

Time plays a fundamental role in both the benefits and challenges of using online discussions as a pedagogical tool. This makes temporal considerations critical both for conducting analyses of how learning takes places through online discussions and for designing effective structures to support discussion activity. However, despite the importance of temporal considerations for online discussions, the majority of research on online discussions and guidance for design does not explicitly address issues of time. This chapter provides an initial foundation for researchers, designers, and instructors of online discussions to engage in temporally aware analysis and design. The authors begin with an overview of the general temporal characteristics of online discussions and the analytic considerations they raise in terms of timescales, data aggregation, and units of analysis. They then use the categories of Duration, Sequence, Pace, and Salience as a framework for unpacking the temporal aspects of online discussions in more detail, providing guidance for designers and instructors to manage temporal challenges and harness temporal opportunities. The authors conclude with a call for greater theorization of temporal properties, processes, and their effects on learning to support more informed analysis and design of online discussions.
Effective E-Learning Strategies for a Borderless World
Authors: Baporikar Neeta
Published: October 2013

e-Commerce, e-Business, e-Shopping, and other terms beginning with the letter “e” are used to refer to the electronic world and the Internet. Hence, when we talk today about e-Learning, we think of a site in the Internet or Intranet that is available to everybody, an illustrated encyclopedia in electronic format, or even a multimedia-based presentation. In fact, all these ideas are far beyond an e-Learning definition. Electronic learning is not only a kind of virtual or distance education to deliver content by electronic means through the use of the Internet, Intranet, or CD-ROM, but it is aimed at effective learning in real time. Formerly known as Computer-Based Training (CBT), e-Learning is increasingly oriented to real-time learning, that is, activities facilitating simultaneous interaction between learners and instructors. In this regard, it is important to analyze the effective strategies that will be used for making e-Learning effective in this borderless world. The objectives of this chapter are to understand the essentials of effective e-Learning Strategies and identify the organizational barriers and facilitators in embedding e-Learning with Knowledge Management. The methodology adopted is an in depth literature review and grounded theory approach with contextual analysis and is focused on the effectiveness of e-Learning from the organizational point of view.
An E-Portfolio to Support E-Learning 2.0
Authors: Sellami Hedia Mhiri
Published: October 2013

ePortfolios have been in use in university for nearly a decade. Students' learning is changing, and the university is faced with e-learning 2.0, which is based on Web 2.0. This chapter introduces e-learning 2.0 and shows that the ePortfolio is currently the ideal environment to accompany it. To emphasize e-learning 2.0, the authors propose to enrich the ePortfolio's structure by adding an item corresponding to e-learning 2.0 artifacts as well as to other new learning sources. Some ePortfolio standards are described to show the lack of such a dedicated item. It is stressed that this proposition concerns the conceptual aspect and not the technical one. It may help follow the current students' tendency as well as the market demand for use. The end of this chapter addresses some difficulties in introducing the ePortfolio and stresses that it is still relevant for e-learning 2.0.
Some Cultural Issues in the Adoption of E-Learning
Authors: Abderrazek Wiem
Published: October 2013

The adoption of Information and Communication Technologies (ICTs) varies from one cultural context to another. This phenomenon of technology acceptance is not new anymore. While it is increasingly common due to globalization in some cultures, its use tends to be rejected by other cultures. Cultural factors are often identified as a crucial influence on the success or failure of Information Systems in general and ICT use in particular. This chapter is a theoretical foundation on which one can base the mutual influence of culture on the use of e-learning technologies. It highlights the cultural factors in macro and micro level that have been investigated in the literature of management. A theoretical basis for analysis in this area is developed using concepts drawn from the Structuration Theory of Giddens (1979). For this purpose, a qualitative exploratory approach has been adopted to address the research question.
Cutting Edge: Smad2 and Smad4 Regulate TGF-β–Mediated Il9 Gene Expression via EZH2 Displacement
Authors: Wang Aibo , Pan Deng , Lee Young-Hee , Martinez Gustavo J. , Feng Xin-hua , Dong Chen
Published: October 2013

IL-9 is a proallergic cytokine produced by a newly proposed Th cell subset, Th9. Th9 cells can be generated by treatment of naive T cells with TGF-β and IL-4 in vitro. However, it is still not clear how TGF-β signaling regulates Th9 differentiation. In this study, we demonstrate that Smad2 and Smad4, two transcriptional factors activated by TGF-β signaling, are required for Th9 differentiation in vitro. Deficiency of Smad2 or Smad4 in T cells resulted in impaired IL-9 expression, which was coincident with enrichment of repressive chromatin modification histone H3 K27 trimethylation and enhanced EZH2 binding to the Il9 locus. Pharmacologic inhibition of EZH2 partially rescued IL-9 production in Smad-deficient Th9 cells. Smad proteins may displace EZH2 directly from the Il9 locus, because Smad2 and Smad4 can bind EZH2. Our data shed light on the molecular mechanisms underlying Th9 cell differentiation, revealing that the TGF-β–Smad2/4–signaling pathway regulates IL-9 production through an epigenetic mechanism.
Tumorigenesis: cell defense against hypoxia?
Authors: Pakravan Nafiseh
Published: October 2013

Microenvironmental elements can directly contribute to the induction and the maintenance of tumor. Oxygen is the main element in the cell microenvironment and hypoxia can affect the process of tumorigenesis. In response to hypoxia, cells change their pattern and characteristics. These changes suggest that it is not just adaptation, but some sort of cell defense against hypoxia. If hypoxia is corrected, then cell defense mechanisms are interrupted. An examination of the process of tumorigenesis helps to design better therapeutic strategies.A systematic review of the English literature was conducted by searching PubMed, Google Scholar, and ISI Web databases for studies on changes that defend and help cells to live in a hypoxic microenvironment. Cells respond to hypoxia by de-differentiation and an increase in heat shock proteins. Angiogenesis and deviation of inflammatory response in favor of hypoxic cell survival also defend and save the oxygen-starved cells from death. Finally, anti-angiogenic therapies and more hypoxia enhance metastasis, as tumors with low oxygen concentration are more malignant than tumors with high oxygen concentration. All these enable cells to migrate away from low oxygen areas and seek a more conducive microenvironment. Therapies that make the microenvironment more hypoxic need to be revised. This has been done for antiangiogenic therapies, previously considered to be anti-tumor approaches. Effective therapies may be correcting therapies which direct the tumor microenvironment towards natural physical/chemical condition. Correcting therapies either bring back tumor cells to a normal form (correct tumor cells) or help the immune system to eradicate tumor cells which can not be corrected.
Sampling versus systematic full lymphatic dissection in surgical treatment of non-small cell lung cancer
Authors: Koulaxouzidis Georgios , Karagkiouzis Grigorios , Konstantinou Marios , Gkiozos Ioannis , Syrigos Konstantinos
Published: October 2013

The extent of mediastinal lymph node assessment during surgery for non-small cell cancer remains controversial. Different techniques are used, ranging from simple visual inspection of the unopened mediastinum to an extended bilateral lymph node dissection. Furthermore, different terms are used to define these techniques. Sampling is the removal of one or more lymph nodes under the guidance of pre-operative findings. Systematic (full) nodal dissection is the removal of all mediastinal tissue containing the lymph nodes systematically within anatomical landmarks. A Medline search was conducted to identify articles in the English language that addressed the role of mediastinal lymph node resection in the treatment of non-small cell lung cancer. Opinions as to the reasons for favoring full lymphatic dissection include complete resection, improved nodal staging and better local control due to resection of undetected micrometastasis. Arguments against routine full lymphatic dissection are increased morbidity, increase in operative time, and lack of evidence of improved survival. For complete resection of non-small cell lung cancer, many authors recommend a systematic nodal dissection as the standard approach during surgery, and suggest that this provides both adequate nodal staging and guarantees complete resection. Whether extending the lymph node dissection influences survival or recurrence rate is still not known. There are valid arguments in favor in terms not only of an improved local control but also of an improved long-term survival. However, the impact of lymph node dissection on long-term survival should be further assessed by large-scale multicenter randomized trials.
Modulation of insulin-like growth factor-1 receptor and its signaling network for the treatment of cancer: current status and future perspectives
Authors: Jin Meizhong , Buck Elizabeth , Mulvihill Mark J.
Published: October 2013

Based on over three decades of pre-clinical data, insulin-like growth factor-1 receptor (IGF-1R) signaling has gained recognition as a promoter of tumorogenesis, driving cell survival and proliferation in multiple human cancers. As a result, IGF-1R has been pursued as a target for cancer treatment. Early pioneering efforts targeting IGF-1R focused on highly selective monoclonal antibodies, with multiple agents advancing to clinical trials. However, despite some initial promising results, recent clinical disclosures have been less encouraging. Moreover, recent studies have revealed that IGF-1R participates in a dynamic and complex signaling network, interacting with additional targets and pathways thereof through various crosstalk and compensatory signaling mechanisms. Such mechanisms of bypass signaling help to shed some light on the decreased effectiveness of selective IGF- 1R targeted therapies (e.g. monoclonal antibodies) and suggest that targeting multiple nodes within this signaling network might be necessary to produce a more effective therapeutic response. Additionally, such findings have led to the development of small molecule IGF-1R inhibitors which also co-inhibit additional targets such as insulin receptor and epidermal growth factor receptor. Such findings have helped to guide the design rationale of numerous drug combinations that are currently being evaluated in clinical trials.
Radiation therapy for primary central nervous system lymphoma
Authors: Shibamoto Yuta
Published: October 2013

Up until the late 1970s, radiation therapy played an important role in the treatment of primary central nervous system lymphoma (PCNSL) but more recently its role has changed due to the increased use of systemic chemotherapy. In this article, the current status of radiotherapy for PCNSL and optimal forms of radiotherapy, including the treatment volume and radiation dose, are discussed. Data from nationwide Japanese surveys of PCNSL patients treated with radiation therapy suggest that the prognosis of PCNSL patients improved during the 1990s, in part due to the use of high-dose methotrexate-containing chemotherapy. The prognosis of patients treated with radiation alone also improved. Radiotherapy still seems to play an important role in the attempt to cure this disease.
Research biopsies in the context of early phase oncology studies: clinical and ethical considerations
Authors: Saggese Matilde , Dua Divyanshu , Simmons Emily , Lemech Charlotte , Arkenau Hendrik-Tobias
Published: October 2013

The Personalized Medicine approach in oncology is a direct result of an improved understanding of complex tumor biology and advances in diagnostic technologies. In recent years, there has been an increased demand for archival and fresh tumor analysis in early clinical trials to foster proof-of-concept biomarker development, to understand resistance mechanisms, and ultimately to assess biological response. Although phase I studies are aimed at defining drug safety, pharmacokinetics, and to recommend a phase II dose for further testing, there is now increasing evidence of mandatory tumor biopsies even at the earliest dose-finding stages of drug development. The increasing demand for fresh tumor biopsies adds to the complexity of novel phase I studies and results in different challenges, ranging from logistical support to ethical concerns. This paper investigates key issues, including patients’ perceptions of research biopsies, the need for accurate informed consent, and alternative strategies that may guide the drug development process.
Hormonal therapy in metastatic prostate cancer: current perspectives and controversies
Authors: Garg Manish , Singh Vishwajeet , Kumar Manoj , Sankhwar Satya Narayan
Published: October 2013

Ever since the introduction of androgen deprivation therapy (ADT) in prostate cancer, various controversial aspects of hormonal therapy have come to light. There has been tremendous progress in this area, marked by several important developments in the availability of various new androgen-suppressing agents and refinements to the existing therapies. Parallel to these developments, various more debatable aspects have arisen in the use of these therapies with regards to their negative impact on quality of life parameters. Various modifications in these hormonal agents, their doses, and protocols have been tried in different scenarios in order to improve ADT tolerability. As a result, these controversies continue to evolve even with optimal use of the androgen ablation therapy. This review assesses the present status of hormonal therapy in metastatic prostate cancer and specifically deals with those aspects of androgen ablation therapy that are still a subject of debate. In spite of the fact that various trials have been conducted, some of which are still ongoing, the multitude of questions related to the best possible use of these hormonal agents have still not been answered. Treatment guidelines concerning these issues are continuing to evolve as progress continues to be made in this field.
Disaster event: Window of opportunity to implement global disaster policies?
Authors: Manyena Siambabala B.
Published: October 2013

Disasters have been predominantly construed as destructive events causing loss of lives, livelihoods and hard-won development. Much less attention has been paid to the constructive nature of disasters as creating potential windows of opportunities to address the overlooked and neglected aspects of disaster risk reduction. Using material from Zimbabwe, this article examines whether the humanitarian crisis, as manifested in the cholera disaster of 2008–2009, created a window of opportunity to accelerate the implementation of the Hyogo Framework for Action. The findings suggest that the humanitarian crisis did not necessarily create a window of opportunity to accelerate the implementation of the framework, owing to (1) inadequate authority and power of the agency responsible for disaster risk reduction, (2) an inadequate legal and institutional framework that outlines clear coordination, accountability mechanisms, resource mobilisation, community participation, and integration of development with regard to disaster risk reduction and (3) a lack of an integrated evidence-based approach to advocate disaster risk reduction in Zimbabwe.
Review: Genetics of helminth resistance in sheep
Authors: Karrow Niel A. , Goliboski Katherine , Stonos Nancy , Schenkel Flavio , Peregrine Andrew
Published: October 2013

Karrow, N. A., Goliboski, K., Stonos, N., Schenkel, F. and Peregrine, A. 2014. Review: Genetics of helminth resistance in sheep. Can. J. Anim. Sci. 94: 1–9. Gastrointestinal helminth parasites are an important source of economic loss to sheep producers. A rapid increase in anthelmintic resistance has occurred around the globe; therefore, the industry is exploring alternative strategies such as genetic selection to control losses attributed to helminth infection. Since helminths have co-evolved with sheep for millions of years, natural selection for enhanced helminth resistance has occurred within certain breeds from various parts of the world. These breeds of sheep are being used to better understand the genetic aspects of helminth resistance. If the genetic variants that contribute to this phenotype can be identified, it may be possible to use selection strategies to introduce resistance alleles into other breeds or to increase their frequency within breeds. This review will provide an up-to-date overview of the pathology of helminth disease, the immune response to helminth infection, and the search for genes that confer helminth resistance.
Genetic and gene expression analysis of dm1, a dwarf mutant from Cucurbita maxima Duch. ex Lam, based on the AFLP method
Authors: Wang Rui , Huang Hexun , Lin Yu'e , Chen Qinghua , Liang Zhaojun , Wu Tingquan
Published: October 2013

Wang, R., Huang, H., Lin, Y., Chen, Q., Liang, Z. and Wu, T. 2014. Genetic and gene expression analysis of dm1, a dwarf mutant from Cucurbita maxima Duch. ex Lam, based on the AFLP method. Can. J. Plant Sci. 94: 293–302. dm1, a dwarf mutant from Cucurbita maxima (Duch. ex Lam) by natural mutation, showed distinct dwarf phenotypes such as shorter vines and fewer and shorter internodes. Genetic analysis indicated that the dm1 mutation was recessive, and the dwarfing character was controlled by a single locus. DNA-AFLP analysis showed that a fragment (MCAG/ETT) was linked with the dwarfing character of dm1 and that the fragment contained 152 base pairs (bp). It was investigated in F2 populations of dm1 and vine plants, and the genetic distance between the MCAG/ETT fragment and dwarf gene in dm1 was 11.2 cM, calculated by JoinMap 3.0 software. In addition, the result of cDNA-AFLP analysis showed that there were 52 differential transcript derived fragments (TDFs) found between dm1 and vine plants. Only four TDFs, A16T12, A16T9, A6T14 and A6T16, were expressed stably and specifically in dm1 plants in subsequent investigation. The four fragments share 71, 79, 87 and 79% nucleic acid sequence similarity with the complete coding sequence of Arabidopsis thaliana histidine kinase 3 (AHK3) mRNA, nucleic acid sequence of Vitis vinifera dihydroflavonol-4-reductase-like (DFRL), nucleic acid sequence of Glycine max histone-lysine N-methyltransferase ATX4-like and nucleic acid sequence of Arabidopsis thaliana histidinol dehydrogenase (HDH), respectively. Bioinformatics analysis indicated that AHK3, DFRL and HDH were respectively related to Cytokinin signaling, indole acetic acid signaling and Ni accumulation, which played important roles in plant growth, so the expression of the four TDFs may contribute to form dwarfism in dm1.
Use of NBPT and ammonium thiosulphate as urease inhibitors with varying surface placement of urea and urea ammonium nitrate in production of hard red spring wheat under reduced tillage management
Authors: Grant C. A.
Published: October 2013

Grant, C. A. 2014. Use of NBPT and ammonium thiosulphate as urease inhibitors with varying surface placement of urea and urea ammonium nitrate in production of hard red spring wheat under reduced tillage management. Can. J. Plant Sci. 94: 329–335. Field studies were conducted at two locations over 3 yr to evaluate the effect of surface placement of urea ammonium nitrate (UAN) and urea fertilizers, with and without the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) on straw and grain yield of hard red spring wheat (Triticum aestivum L.) grown under reduced tillage management. Ammonium thiosulphate (ATS) was also evaluated as a urease inhibitor with UAN. Surface sprayed applications of UAN were frequently less effective than dribble-banded UAN applications or broadcast or dribble-banded urea in increasing grain or straw yield of hard red spring wheat. Use of NBPT with the sprayed UAN increased its effectiveness, so that grain and straw yields were similar to those with urea or with surface dribble-banded UAN. Addition of NBPT to broadcast or banded urea did not increase straw or grain yield under the conditions of this study. While there was some indication that use of ATS with UAN may have had a limited effect on fertilizer efficiency, it did not increase final grain yield as compared with dribble-banded or spray UAN applied alone or with NBPT. If surface nitrogen (N) applications are used in reduced tillage systems, spray applications of UAN should be avoided in favour of dribble-band applications, or the use of urea. Alternately, NBPT may be effective in improving the efficacy of spray UAN.
The dispersion characteristics of air pollution from the world's megacities
Authors: Cassiani M. , Stohl A. , Eckhardt S.
Published: October 2013

Abstract. Megacities are extreme examples of the continuously growing urbanization of the human population that pose (new) challenges to the environment and human health at a local scale. However, because of their size megacities also have larger-scale effects, and more research is needed to quantify their regional- and global-scale impacts. We performed a study of the characteristics of pollution plumes dispersing from a group of 36 of the world's megacities using the Lagrangian particle model FLEXPART and focusing on black carbon (BC) emissions during the years 2003–2005. BC was selected since it is representative of combustion-related emissions and has a significant role as a short-lived climate forcer. Based on the BC emissions two artificial tracers were modeled: a purely passive tracer and one subject to wet and dry deposition more closely resembling the behavior of a true aerosol. These tracers allowed us to investigate the role of deposition processes in determining the impact of megacities' pollutant plumes. The particles composing the plumes have been sampled in space and time. The time sampling allowed us to investigate the evolution of the plume from its release up to 48 days after emission and to generalize our results for any substance decaying with a timescale sufficiently shorter than the time window of 48 days. The physical characteristics of the time-averaged plume have been investigated, and this showed that, although local conditions are important, overall a city's latitude is the main factor influencing both the local and the regional-to-global dispersion of its pollution. We also repeated the calculations of some of the regional-pollution-potential metrics previously proposed by Lawrence et al. (2007), thus extending their results to a depositing scalar and retaining the evolution in time for all the plumes. Our results agreed well with their previous results despite being obtained using a totally different modeling framework. For the environmental impact on a global scale we focused on the export of mass from the megacities to the sensitive polar regions. We found that the sole city of Saint Petersburg contributes more to the lower-troposphere pollution and deposition in the Arctic than the whole ensemble of Asian megacities. In general this study showed that the pollution of urban origin in the lower troposphere of the Arctic is mainly generated by northern European sources. We also found that the deposition of the modeled artificial BC aerosol in the Antarctic due to megacities is comparable to the emissions of BC generated by local shipping activities. Finally multiplying population and ground level concentration maps, we found that the exposure of human population to megacity pollution occurs mainly inside the city boundaries, and this is especially true if deposition is accounted for. However, some exceptions exist (Beijing, Tianjin, Karachi) where the impact on population outside the city boundary is larger than that inside the city boundary.
Acetaldehyde exchange above a managed temperate mountain grassland
Authors: Hörtnagl L. , Bamberger I. , Graus M. , Ruuskanen T. M. , Schnitzhofer R. , Walser M. , Unterberger A. , Hansel A. , Wohlfahrt G.
Published: October 2013

Abstract. An overview of acetaldehyde exchange above a managed temperate mountain grassland in Austria over four growing seasons is presented. The meadow acted as a net source of acetaldehyde in all four years, emitting between 7 and 28 mg C m−2 over the whole growing period. The cutting of the meadow resulted in huge acetaldehyde emission bursts on the day of harvesting or one day later. During undisturbed conditions, both uptake and emission fluxes were recorded. The bidirectional nature of acetaldehyde fluxes was also reflected by clear diurnal cycles during certain time periods, indicating strong deposition processes before the 1st cut and emission towards the end of the growing season. The analysis of acetaldehyde compensation points revealed a complex relationship between ambient acetaldehyde mixing ratios and respective fluxes, significantly influenced by multiple environmental parameters and variable throughout the year. As a major finding of this study, we identified both a positive and negative correlation between concentration and flux on a daily scale, where soil temperature and soil water content were the most significant factors in determining the direction of the slope. In turn, this bidirectional relationship on a daily scale resulted in compensation points between 0.40 ppbv and 0.54 ppbv, which could be well explained by collected ancillary data. We conclude that in order to model acetaldehyde fluxes at the site in Neustift on a daily scale over longer time periods, it is crucial to know the type of relationship, i.e. the direction of the slope, between mixing ratios and fluxes on a given day.
Numerical simulation of "An American Haboob"
Authors: Vukovic A. , Vujadinovic M. , Pejanovic G. , Andric J. , Kumjian M. R. , Djurdjevic V. , Dacic M. , Prasad A. K. , El-Askary H. M. , Paris B. C. , Petkovic S. , Nickovic S. , Sprigg W. A.
Published: October 2013

Abstract. A dust storm of fearful proportions hit Phoenix in the early evening hours of 5 July 2011. This storm, an American haboob, was predicted hours in advance because numerical, land-atmosphere modeling, computing power and remote sensing of dust events have improved greatly over the past decade. High resolution numerical models are required for accurate simulation of the small-scales of the haboob process, with high velocity surface winds produced by strong convection and severe downbursts. Dust productive areas in this region consist mainly of agricultural fields, with soil surfaces disturbed by plowing and tracks of land in the high Sonoran desert laid barren by ongoing draught. Model simulation of the 5 July 2011 dust storm uses the coupled atmospheric-dust model NMME-DREAM with 3.5 km horizontal resolution. A mask of the potentially dust productive regions is obtained from the land cover and the Normalized Difference Vegetation Index (NDVI) data from the Moderate Resolution Imaging Spectroradiometer (MODIS). Model results are compared with radar and other satellite-based images and surface meteorological and PM10 observations. The atmospheric model successfully hindcasted the position of the front in space and time, with about 1 h late arrival in Phoenix. The dust model predicted the rapid uptake of dust and high values of dust concentration in the ensuing storm. South of Phoenix, over the closest source regions (~ 25 km), the model PM10 surface dust concentration reached ~ 2500 μg m−3, but underestimated the values measured by the PM10stations within the city. Model results are also validated by the MODIS aerosol optical depth (AOD), employing deep blue (DB) algorithms for aerosol loadings. Model validation included Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), equipped with the lidar instrument, to disclose the vertical structure of dust aerosols as well as aerosol subtypes. Promising results encourage further research and application of high-resolution modeling and satellite-based remote sensing to warn of approaching severe dust events and reduce risks for safety and health.
Measuring the Antarctic ozone hole with the new Ozone Mapping and Profiler Suite (OMPS)
Authors: Kramarova N. A. , Nash E. R. , Newman P. A. , Bhartia P. K. , McPeters R. D. , Rault D. F. , Seftor C. J. , Xu P. Q.
Published: October 2013

Abstract. The new Ozone Mapping and Profiler Suite (OMPS) launched on the Suomi National Polar-orbiting Partnership satellite in October 2011 gives a more detailed view of the development of the Antarctic ozone hole than ever before. This instrumental suite extends the long series of satellite ozone measurements that go back to the early 1970s. The OMPS includes two modules – nadir and limb – to measure profile and total ozone concentrations. The new limb module is designed to measure the vertical profile of ozone between the lowermost stratosphere and the mesosphere. The OMPS observations over Antarctica show excellent agreement with the measurements obtained from independent satellite and ground-based instruments. This validation demonstrates that OMPS data can ably extend the ozone time series over Antarctica in the future. The OMPS observations are used to monitor and characterize the evolution of the 2012 Antarctic ozone hole. While large ozone losses were observed in September 2012, a strong ozone rebound occurred in October and November 2012. This ozone rebound is characterized by rapid increases of ozone at mid-stratospheric levels and a splitting of the ozone hole in early November. The 2012 Antarctic ozone hole was the second smallest on record since 1988.
Inferring regional sources and sinks of atmospheric CO2 from GOSAT XCO2 data
Authors: Deng F. , Jones D. B. A. , Henze D. K. , Bousserez N. , Bowman K. W. , Fisher J. B. , Nassar R. , O'Dell C. , Wunch D. , Wennberg P. O. , Kort E. A. , Wofsy S. C. , Blumenstock T. , Deutscher N. M. , Griffith D. , Hase F. , Heikkinen P. , Sherlock V. , Strong K. , Sussmann R. , Warneke T.
Published: October 2013

Abstract. We have examined the utility of retrieved column-averaged, dry-air mole fractions of CO2 (XCO2) from the Greenhouse Gases Observing Satellite (GOSAT) for quantifying monthly, regional flux estimates of CO2, using the GEOS-Chem four-dimensional variational (4D-Var) data assimilation system. We focused on assessing the potential impact of biases in the GOSAT CO2 data on the regional flux estimates. Using different screening and bias correction approaches, we selected three different subsets of the GOSAT XCO2 data for the 4D-Var inversion analyses, and found that the inferred global fluxes were consistent across the three XCO2 inversions. However, the GOSAT observational coverage was a challenge for the regional flux estimates. In the northern extratropics, the inversions were more sensitive to North American fluxes than to European and Asian fluxes due to the lack of observations over Eurasia in winter and over eastern and southern Asia in summer. The regional flux estimates were also sensitive to the treatment of the residual bias in the GOSAT XCO2 data. The largest differences obtained were for Temperate North America and Temperate South America, for which the largest spread between the inversions was 1.02 Pg C and 0.96 Pg C, respectively. In the case of Temperate North America, one inversion suggested a strong source, whereas the second and third XCO2 inversions produced a weak and strong sink, respectively. Despite the discrepancies in the regional flux estimates between the three XCO2 inversions, the a posteriori CO2 distributions were in good agreement (with a mean difference between the three inversions of typically less than 0.5 ppm) with independent data from the Total Carbon Column Observing Network (TCCON), the surface flask network, and from the HIAPER Pole-to-Pole Observations (HIPPO) aircraft campaign. The discrepancy in the regional flux estimates from the different inversions, despite the agreement of the global flux estimates, suggests the need for additional work to determine the minimum spatial scales at which we can reliably quantify the fluxes using GOSAT XCO2. The fact that the a posteriori CO2 from the different inversions were in good agreement with the independent data although the regional flux estimates differed significantly, suggests that innovative ways of exploiting existing datasets, and possibly additional observations, are needed to better evaluate the inferred regional flux estimates.
Impact of the Kuroshio intrusion on the nutrient inventory in the upper northern South China Sea: insights from an isopycnal mixing model
Authors: Du C. , Liu Z. , Dai M. , Kao S.-J. , Cao Z. , Zhang Y. , Huang T. , Wang L. , Li Y.
Published: October 2013

Abstract. Based on four cruises covering a seasonal cycle in 2009–2011, we examined the impact of the Kuroshio intrusion, featured by extremely oligotrophic waters, on the nutrient inventory in the central northern South China Sea (NSCS). The nutrient inventory in the upper 100 m of the water column in the study area ranged from ∼200 to ∼290 mmol m−2 for N + N (nitrate plus nitrite), from ∼13 to ∼24 mmol m−2 for soluble reactive phosphate and from ∼210 to ∼430 mmol m−2 for silicic acid. The nutrient inventory showed a clear seasonal pattern with the highest value appearing in summer, while the N + N inventory in spring and winter had a reduction of ∼13 and ∼30%, respectively, relative to that in summer. To quantify the extent of the Kuroshio intrusion, an isopycnal mixing model was adopted to derive the proportional contribution of water masses from the SCS proper and the Kuroshio along individual isopycnal surfaces. The derived mixing ratio along the isopycnal plane was then employed to predict the genuine gradients of nutrients under the assumption of no biogeochemical alteration. These predicted nutrient concentrations, denoted as Nm, are solely determined by water mass mixing. Results showed that the nutrient inventory in the upper 100 m of the NSCS was overall negatively correlated to the Kuroshio water fraction, suggesting that the Kuroshio intrusion significantly influenced the nutrient distribution in the SCS and its seasonal variation. The difference between the observed nutrient concentrations and their corresponding Nm allowed us to further quantify the nutrient removal/addition associated with the biogeochemical processes on top of the water mass mixing. We revealed that the nutrients in the upper 100 m of the water column had a net consumption in both winter and spring but a net addition in fall.
High soil solution carbon und nitrogen concentrations in a drained Atlantic bog are reduced to natural levels by 10 yr of rewetting
Authors: Frank S. , Tiemeyer B. , Gelbrecht J. , Freibauer A.
Published: October 2013

Abstract. Artificial drainage of peatlands causes dramatic changes in the release of greenhouse gases and in the export of dissolved carbon (C) and nutrients to downstream ecosystems. Rewetting anthropogenically altered peatlands offers a possibility to reduce nitrogen (N) and C losses. In this study, we investigate the impact of drainage and rewetting on the cycling of dissolved C and N as well as on dissolved gases over a period of 1 yr and 4 month, respectively. The peeper technique was used to receive a high vertical sampling resolution. Within one Atlantic bog complex a near natural site, two drained grasslands sites with different mean water table positions, and a former peat cutting area rewetted 10 yr ago were chosen. Our results clearly indicate that drainage increased the concentration of dissolved organic carbon (DOC), ammonia, nitrate and dissolved organic nitrogen (DON) compared to the near natural site. Drainage depth further determined the release and therefore the concentration level of DOC and N species, but the biochemical cycling and therefore dissolved organic matter (DOM) quality and N species composition were unaffected. Thus, especially deep drainage can cause high DOC losses. In general, DOM at drained sites was enriched in aromatic moieties as indicated by SUVA280 and showed a higher degradation status (lower DOC to DON ratio) compared to the near natural site. At the drained sites, equal C to N ratios of uppermost peat layer and DOC to DON ratio of DOM in soil solution suggest that the uppermost degraded peat layer is the main source of DOM. Nearly constant DOC to DON ratios and SUVA280 values with depth furthermore indicated that DOM moving downwards through the drained sites remained largely unchanged. DON and ammonia contributed most to the total dissolved nitrogen (TN). The subsoil concentrations of nitrate were negligible due to strong decline in nitrate around mean water table depth. Methane production during the winter months at the drained sites moved downwards to areas which were mostly water saturated over the whole year (>40 cm). Above these depths, the recovery of the water table in winter months led to the production of nitrous oxide around mean water table depth at drained sites. 10 yr after rewetting, the DOM quality (DOC to DON ratio and SUVA280) and quantity were comparable to the near natural site, indicating the re-establishment of mostly pristine biochemical processes under continuously water logged conditions. The only differences occur in elevated dissolved methane and ammonia concentrations reflecting the former disturbance by drainage and peat extraction. Rewetting via polder technique seems to be an appropriate way to revitalize peatlands on longer timescales and to improve the water quality of downstream water bodies.