bluuebunny/crossref_metadata_2025 huggingface dataset:
Limited alpine climatic warming and modeled phenology advancement for three alpine species in the Northeast United States
Authors: Kimball Kenneth D. , Davis Michael L. , Weihrauch Douglas M. , Murray Georgia L. D. , Rancourt Kenneth
Published: September 2014

• Premise of the study: Most alpine plants in the Northeast United States are perennial and flower early in the growing season, extending their limited growing season. Concurrently, they risk the loss of reproductive efforts to late frosts. Quantifying long‐term trends in northeastern alpine flower phenology and late‐spring/early‐summer frost risk is limited by a dearth of phenology and climate data, except for Mount Washington, New Hampshire (1916 m a.s.l.).

• Methods: Logistic phenology models for three northeastern US alpine species (Diapensia lapponica, Carex bigelowii and Vaccinium vitis‐idaea) were developed from 4 yr (2008–2011) of phenology and air temperature measurements from 12 plots proximate to Mount Washington's long‐term summit meteorological station. Plot‐level air temperature, the logistic phenology models, and Mount Washington's climate data were used to hindcast model yearly (1935–2011) floral phenology and frost damage risk for the focal species.

• Key results: Day of year and air growing degree‐days with threshold temperatures of −4°C (D. lapponica and C. bigelowii) and −2°C (V. vitis‐idaea) best predicted flowering. Modeled historic flowering dates trended significantly earlier but the 77‐yr change was small (1.2–2.1 d) and did not significantly increase early‐flowering risk from late‐spring/early‐summer frost damage.

• Conclusions: Modeled trends in phenological advancement and sensitivity for three northeastern alpine species are less pronounced compared with lower elevations in the region, and this small shift in flower timing did not increase risk of frost damage. Potential reasons for limited earlier phenological advancement at higher elevations include a slower warming trend and increased cloud exposure with elevation and/or inadequate chilling requirements.
Social Media Activities
Authors: Heinonen Kristina
Published: September 2014

Consumers are increasingly consuming, participating, contributing, and sharing different types of online content. This is influencing the marketing activities traditionally controlled and performed by companies. The aim of this chapter is to conceptualize the activities consumers perform in social media. Social media denote content created by individual consumers such as online ratings or verbal reviews, online message boards/forums, photos/video sites, blogs, tags, and social networking sites. A conceptual framework for consumers' social media activities is developed and qualitatively substantiated. Social media activities are based on the motives for the activities, including information, social connection, and entertainment. The chapter contributes to research on social media and online communities by describing user behavior and motivations related to the user-created services. Managerially, the study deepens the understanding of different challenges related to users' activities on social media and the motivations associated with those activities.
Building and Maintaining Relationships through Social Media
Authors: Agozzino Alisa
Published: September 2014

In recent years, social media tools such as Facebook, Twitter, YouTube, and blogs have rocked the higher education world. No longer is just being present on these mediums enough. Integration of social media tools into daily practices through monitoring, teaching, and collaboration allows those in higher education to build and maintain relationships with key publics. From devising social media goals and objectives to monitoring channels and evaluating efforts, social media can be integrated into the higher education arena. In this chapter, multiple dimensions of social media tools and the various ways those in higher education can integrate those tools into operation are exposed and elaborated upon. In an effort to provide readers with best practices, ideas are shared to present those in higher education with optimal ways to connect, build, and maintain relationships with others both internally and externally.
Copyright and Licensing Essentials for Librarians and Copyright Owners in the Digital Age
Authors: Moon Anne
Published: September 2014

So much of what we as librarians do involves some aspect of copyright, whether it is document delivery, electronic reserves, online learning tools, and course management systems (e.g. Blackboard), or online modules that allow one to share one's references and full-text attachments with others (e.g. RefShare). It is therefore important that we become involved in copyright- and licensing negotiations with our online content providers. We also have an obligation to not only familiarize ourselves with but also to tutor our library patrons in terms of copyright legislation, bearing in mind that they may be held personally liable for their use of copyrighted materials through digital interfaces (Graveline, 2011).
Persuasive Games as Social Action Agents
Authors: Ruggiero Dana
Published: September 2014

Persuasive games are an interdisciplinary area covering a range of fields. This article examines persuasive games through current trends in research as potential agents of social action. The implications of persuasive games for learning are analyzed through education and communication theories, suggesting that persuasive techniques are of primary importance and that procedures and ethos connect learners to experiences. The article first provides a historical overview of persuasive games, highlighting key background and influences. It then defines persuasive games through learning and communication theories, and discusses the implications of persuasive games as social action agents in research, policy, and practice.
Articulations and Rearticulations
Authors: Gilberds Heather
Published: September 2014

The adoption of western models of journalism is a hallmark of media democratization movements in post-conflict, transitional or developing nations. However, media strengthening programs have received wide criticism from critical development scholars. This chapter interrogates the assumptions that underlie media development projects in Africa, which work to establish or reform journalism practices, by drawing on a case study of media strengthening in Rwanda. Drawing on discourse theory, it maps the discursive field that forms the basis for international assistance to build media capacity in developing and post-conflict regions. It also highlights the ways dominant development models are resisted in and through discourse, thereby drawing attention to the fluid and contingent operations of power that manifest in such institutionalized sites of knowledge production.
Traditional to Hybrid
Authors: Li Rowena
Published: September 2014

Drawn from first-hand teaching and learning experiences, this chapter seeks to explore social media tools and their unique features in adapting traditional face-to-face courses to the hybrid learning environment. It examines the transformed roles of instructors and students, as well as their changing pedagogical, social, and psychological needs. It also demonstrates how social media can be used to meet the challenges of both hybrid and online instruction in higher education. This chapter provides faculty, administrators, and practitioners a better understanding of the roles of the instructors and students in a hybrid setting and also offers guidance to instructors on how to involve social media tools in a hybrid learning environment to enhance students' learning experiences.
Access Control Models for Online Social Networks
Authors: Sayaf Rula , Clarke Dave
Published: September 2014

Access control is one of the crucial aspects in information systems security. Authorizing access to resources is a fundamental process to limit potential privacy violations and protect users. The nature of personal data in online social networks (OSNs) requires a high-level of security and privacy protection. Recently, OSN-specific access control models (ACMs) have been proposed to address the particular structure, functionality and the underlying privacy issues of OSNs. In this survey chapter, the essential aspects of access control and review the fundamental classical ACMs are introduced. The specific OSNs features and review the main categories of OSN-specific ACMs are highlighted. Within each category, the most prominent ACMs and their underlying mechanisms that contribute enhancing privacy of OSNs are surveyed. Toward the end, more advanced issues of access control in OSNs are discussed. Throughout the discussion, different models and highlight open problems are contrasted. Based on these problems, the chapter is concluded by proposing requirements for future ACMs.
Protocol Interactions among User Agents, Application Servers, and Media Servers
Authors: Amirante Alessandro , Castaldi Tobia , Miniero Lorenzo , Romano Simon Pietro
Published: September 2014

In this chapter, the authors focus on the complex interactions involving the various actors participating in a multimedia session over the Internet. More precisely, bearing in mind the current standard proposals coming from both the 3GPP and the IETF, they investigate some of the issues that have to be faced when separation of responsibilities comes to the fore. The scenario the authors analyze is one in which one or more user agents are put into communication with a media server through the mediation of an application server. In such scenario, the application server does play the role of a middlebox for all that concerns signaling, since it is responsible for the transparent negotiation of a session among the entities (the user agents on one side and the media server on the other) that will be exchanging media during the communication phase. In this chapter, the authors highlight that protocol interactions become really complex under the depicted circumstances. They provide a survey of the current standardization efforts related to media control, together with a discussion of open issues and potential solutions.
Stepping into the (Social Media) Game
Authors: Sanderson Jimmy
Published: September 2014

This chapter explores how rookie athletes in Major League Baseball (MLB), the National Basketball Association (NBA), National Football League (NFL), and National Hockey League (NHL), used Twitter as an identity expression tool. A representative sample of tweets from athletes selected in the first round of the 2011 amateur draft of each sports league was selected for analysis. Results revealed that identity manifested in the following ways: (a) Athletes as dedicated workers; (b) Athletes as pop culture consumers; (c) Athletes as sports fans; (d) Athletes as motivators; (e) Athletes as information seekers; and (f) Athletes as everyday people. Through social media, athletes can more actively and diversely assert their identity. This action fosters identification, liking, and parasocial interaction with fans as athletes appear more approachable and similar. The ability to construct and disseminate a variety of identities holds important implications for athletes, which are discussed in the concluding section of the chapter.
Social Media and other Web 2.0 Technologies as Communication Channels in a Cross-Cultural, Web-Based Professional Communication Project
Authors: Zemliansky Pavel , Goroshko Olena
Published: September 2014

In recent years, cross-national web-based teaching projects have become very popular in many fields. During such projects, participants from different countries work together on collaborative tasks. Communications among project participants take place over the Internet, including via social media. In this chapter, the author reports the results of social media use in one such project, which brought together students from the United States and Ukraine. A pre and post project survey taken by the participants demonstrate the main opportunities and challenges afforded by social media to educators. The reporting and analysis of the survey results are preceded by a review of relevant literature, which contextualizes our findings.
New Media and the Changing Public Sphere in Uganda
Authors: Javuru Kennedy
Published: September 2014

This chapter gives an exploratory overview of the emergence and growth of new media in Uganda and how the alternative nature of new media is scaffolding the notion of citizenship and deliberative democracy. The chapter also suggests that despite the new found vigour, it is too early to say whether the Ugandan new media landscape have so far become a true alternative or complementary participatory space or a genuine platform for the distribution of uncensored information. It concludes that Ugandans use new media more for social interaction and dissemination of information (in a limited way) than as an alternative political public sphere. However, there are signs that online media is emerging and the anecdotes presented in this chapter indicate the potential of this media to be a place of participation and deliberation and reducing the authoritarian control of the communicative space.
Personality and Social Media Use
Authors: Correa Teresa , Bachmann Ingrid , Hinsley Amber W. , Gil de Zúñiga Homero
Published: September 2014

Research on digital media has mostly paid attention to users' demographics, motivations, and efficacy, but with increasingly popular web tools like social media, it is important to study more stable psychological characteristics such as users' personality traits, as they may significantly affect how people use the Web to communicate and socialize. Relying on the “Big Five Framework” as a theoretical approach, this chapter explores such relationships. Survey data from a national sample of U.S. adults show that more extraverted people are more likely to use social networking sites, instant messaging, and video chats, while those more open to new experiences tend to use social networking sites more frequently. Also, emotional stability is a negative predictor of social networking site use. That is, individuals who are more anxious and unstable tend to rely on these sites. When looking at a specific use of social media–to create political content—emotional stability was a negative predictor, whereas extraversion had a positive impact. These findings confirm the usefulness of combining explorations of personality and digital media usage.
Debunking Intermediary Censorship Framework in Social Media via a Content Retrieval and Classification Software
Authors: Navanopparatskul Baramee , Sinthupinyo Sukree , Ramasoota Pirongrong
Published: September 2014

Following the enactment of computer crime law in Thailand, online service providers are compelled to control illegal content including content that is deemed harmful or problematic. This situation leads to self-censorship of intermediaries, often resulting in overblocking to avoid violating the law. Such filtering flaw both infringes users' freedom of expression and impedes the business of OSPs in Thailand. The Innovative Retrieval System (IRS) is thus developed to investigate intermediary censorship in online discussion forum, Pantip.com, as a case study of social media. The result shows that there is no consistency of censorship pattern on the website at all. The censorship criteria depend on type of content in each forum. Overblocking is also high, over 70% of removed content, due to intimidation of governmental agencies, lawsuits from business organizations, and fear of intermediary liability. Website administrator admitted that he would cut off some users to avoid business troubles.
Building Marketing Relationships on Twitter
Authors: Watkins Brandi A. , Lewis Regina
Published: September 2014

The current study applies a relationship marketing approach to examine how universities use Twitter to communicate with their audiences. To explore social media strategies related to top-ranked universities' Twitter activity, Kotler's (1992) model of five levels of relationship building was refined and operationalized. A content analysis of 1375 tweets distributed by 22 universities was conducted to evaluate the level of relationship building that universities establish through social media in order to engage with current and prospective students, alumni, donors, and external audiences. The authors conclude that top-ranked universities are more likely to engage primarily in reactive relationship building, which can be characterized as the broadcast of an original message with opportunities for followers to initiate post-communication interaction. Results of the message orientation analysis reveal that the vast majority of tweets in the sample were used to give opinion, suggestion, or information.
Is Social Media Marketing Really Working?
Authors: Saavedra Felipe Uribe , Criado Josep Rialp , Andreu Joan Llonch
Published: September 2014

Online social networks have become the fastest growing phenomenon on the Internet and firms are beginning to take advantage of them as a marketing tool. However, the strategic importance of social media marketing is not yet clear, given the novelty and the difficulty of measuring its impact on business performance. This study uses data from 191 Spanish firms from several sectors to measure the impact of the intensity of use of social media marketing on the relationship between the dynamic capabilities of market orientation and entrepreneurial orientation, and business performance. The results provide evidence of the moderating effects of social media marketing intensity on the strength of the mentioned relations and the importance of a strong and committed marketing strategy on digital social networks for businesses.
Italian Undergraduates Join Facebook, but Keep a Critical Distance
Authors: Ferri Paolo , Cavalli Nicola , Mangiatordi Andrea , Micheli Marina , Pozzali Andrea , Scenini Francesca , Serenelli Fabio
Published: September 2014

Facebook is the most popular social network site in Italy, and its usage is particularly spread among younger generations. This paper explores how undergraduate students use Facebook, and what meanings they attach to it. Research was performed in 2008 and in 2009 at a Italian university, with a triangulation of quantitative and qualitative methodology. The authors' survey data show the quick adoption of Facebook. In 2008 half of the students were completely unfamiliar with Facebook, while in 2009 59% of them were using it on a regular basis. Evidence coming from semi-structured interviews with randomly selected university students show that the massive adoption of Facebook goes hand in hand with a general critical attitude. Concerns about privacy issues were common, and they can also lead to a kind of detachment from this site. Implications on the perspective use of Facebook as an educational tool are discussed in the paper.
Old Media, New Media Sources
Authors: Wallsten Kevin
Published: September 2014

This paper contributes to the growing literature on how “new media” is influencing “old media” by tracking references to an extensive list of political blogs in stories run by seventeen prominent print media outlets during the last ten years. The findings presented here show that although journalists frequently use political bloggers as sources in their news coverage, they only reference certain blogs in certain ways at certain times. To be precise, journalists turn to political blogs primarily during national election campaigns and this turn is commonly in the direction of a relatively small group of interactive, liberal blogs.
Capturing and Conveying Chamorro Cultural Knowledge Using Social Media
Authors: San Nicolas-Rocca Tonia , Parrish James
Published: September 2014

The Chamorro people have a long history and rich cultural traditions that have survived the affects of colonization and loss of political control. However, these traditions are in danger of being lost if they are not passed from one generation to the next. The purpose of this study is to understand if information and communication technologies, specifically social media, are used to capture and convey Chamorro cultural knowledge. Two data collection methods were used to understand the type(s) of Chamorro cultural knowledge that is valued, and what social media is used by the Chamorro people today to capture and convey cultural knowledge. The results indicate that the Chamorro people today share the core Chamorro cultural values, and do use information and communication technologies, including social media to capture and convey Chamorro cultural knowledge.
Challenges and Opportunities of Consumer Empowerment in Online Reputation Management
Authors: Vollero Agostino , Siano Alfonso
Published: September 2014

This chapter addresses the role of consumer empowerment in a social media context and its influence on the building of an online reputation. The main objective of the research herein is to delineate the “new” power of consumers when they operate within social media, such as blogs, social network sites, opinion platforms, and/or reputation-based systems, etc. To this end, the chapter aims to answer the following research questions: “What are the different categories and features of online consumer empowerment?” and “What is the role of empowered consumers in maintaining/developing a favourable online brand/corporate reputation?” From a practical standpoint, the identification of the decisive factors that support a firm's e-reputation can indicate how an organisation could benefit from online consumer empowerment, without being overwhelmed by it. Moving to conceptual implications, the prime value of this chapter is that it attempts to narrow the gap in the field in terms of existing research and suggests online reputation management as an interpretative key of a modern conceptualisation of e-marketing.
Digital Social Media Detox (DSMD)
Authors: White Theresa Renee
Published: September 2014

This chapter presents the findings of an empirical, qualitative, one-day intervention, in which 25 college students were invited to leave all digital technology at home and participate in ten hours of face-to-face communication. The project involved alternative activities providing an opportunity for students to socialize and interact without the distraction of digital technology, while affording the investigators an opportunity to observe patterns of social behavior and communication. Those findings are offered to illuminate the potential effects of overuse of digital social media, the pedagogical challenges in a contemporary educational environment, and the social problems we face as a result.
Technical efficiency differentials in oil palm processing technologies in Cross River State, Nigeria
Authors: Abdulsalam Zakari , Nandi James Asu , Ahmed Ben
Published: September 2014

This research analyzed technical efficiency differentials between traditional and improved oil palm processing technologies in Cross River State, Nigeria. A multistage sampling technique was used to select 164 processors. Data were collected through questionnaire and analysed using stochastic frontier. Results revealed mean efficiency of 62% for traditional and 81% for improved technologies. Implying that, no need for the development of a new technology; however, production can be improved using current available technologies. Labour, fresh fruit, depreciation cost and other variables costs were found to affect technical efficiency of traditional processors positively while labour, fresh fruit and other variables costs positively affect improved technologies users’ technical efficiency. Determinants of technical efficiency for both groups of processors were processing experience, educational level and access to extension contact. It was recommended that adoption of improved technologies for processing oil palm should be encouraged by government through extension service and credit facilities. DOI: http://dx.doi.org/10.4038/jas.v9i3.7424The Journal of Agricultural Sciences, 2014, vol.9, no3: p.109-117
Genetic control of yield and yield related traits in selected upland cotton varieties of Pakistan
Authors: Shah Syed Awais Sajid , Akhtar Lal Hussain , Minhas Rashid , Bukhari Muhammad Shahjahan , Shah Syed Sajid Masood , Azhar Faqir Muhammad
Published: September 2014

Inheritance pattern of some polygenic characters were studied in 5 x 5 F1 diallel hybrids and their parents of upland cotton. 20 F1 hybrids and their parents were grown in field under randomized complete block design at experimental area of the Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad. Diallel analysis was used to determine the mode of gene action and genetic components for various yield related traits like plant height, monopodial branches plant-1, sympodial branches plant-1, bolls plant-1, boll weight and seed cotton yield plant-1. Results of regression coefficients showed that all the characters were fit for genetic analysis. Additive type of gene action with partial dominance and over dominance were involved for the expression of the traits studied. Results suggested that these characters can be improved through appropriate selection method or by hybrid development. DOI: http://dx.doi.org/10.4038/jas.v9i3.7435 The Journal of Agricultural Sciences, 2014, vol.9, no3: p.129-138
Evidence for divergence in cuticular hydrocarbon sex pheromone between California and Mississippi (United States of America) populations of bark beetle parasitoid Roptrocerus xylophagorum (Hymenoptera: Pteromalidae)
Authors: Sullivan Brian T. , Erbilgin Nadir
Published: September 2014

Roptrocerus xylophagorum (Ratzeburg) (Hymenoptera: Pteromalidae) is a common Holarctic parasitoid of the larvae and pupae of bark beetles (Coleoptera: Curculionidae: Scotytinae). In no-choice laboratory bioassays, we found that male wasps derived either from northern California or southwestern Mississippi, United States of America more frequently displayed sexual behaviours (including mounting, wing fanning, and copulation attempts) to glass bulb decoys treated with hexane cuticular washes of females derived from the same parasitoid population rather than the distant population. This result suggests that the composition of the cuticular hydrocarbon sex pheromone has diverged between eastern and western populations and is consistent with previous data indicating that R. xylophagorum may consist of more than one species.
Resident Alveolar Macrophages Suppress, whereas Recruited Monocytes Promote, Allergic Lung Inflammation in Murine Models of Asthma
Authors: Zasłona Zbigniew , Przybranowski Sally , Wilke Carol , van Rooijen Nico , Teitz-Tennenbaum Seagal , Osterholzer John J. , Wilkinson John E. , Moore Bethany B. , Peters-Golden Marc
Published: September 2014

The role and origin of alveolar macrophages (AMs) in asthma are incompletely defined. We sought to clarify these issues in the context of acute allergic lung inflammation using house dust mite and OVA murine models. Use of liposomal clodronate to deplete resident AMs (rAMs) resulted in increased levels of inflammatory cytokines and eosinophil numbers in lavage fluid and augmented the histopathologic evidence of lung inflammation, suggesting a suppressive role for rAMs. Lung digests of asthmatic mice revealed an increased percentage of Ly6Chigh/CD11bpos inflammatory monocytes. Clodronate depletion of circulating monocytes, by contrast, resulted in an attenuation of allergic inflammation. A CD45.1/CD45.2 chimera model demonstrated that recruitment at least partially contributes to the AM pool in irradiated nonasthmatic mice, but its contribution was no greater in asthma. Ki-67 staining of AMs supported a role for local proliferation, which was increased in asthma. Our data demonstrate that rAMs dampen, whereas circulating monocytes promote, early events in allergic lung inflammation. Moreover, maintenance of the AM pool in the early stages of asthmatic inflammation depends on local proliferation, but not recruitment.
Early or Late IL-10 Blockade Enhances Th1 and Th17 Effector Responses and Promotes Fungal Clearance in Mice with Cryptococcal Lung Infection
Authors: Murdock Benjamin J. , Teitz-Tennenbaum Seagal , Chen Gwo-Hsiao , Dils Anthony J. , Malachowski Antoni N. , Curtis Jeffrey L. , Olszewski Michal A. , Osterholzer John J.
Published: September 2014

The potent immunoregulatory properties of IL-10 can counteract protective immune responses and, thereby, promote persistent infections, as evidenced by studies of cryptococcal lung infection in IL-10–deficient mice. To further investigate how IL-10 impairs fungal clearance, the current study used an established murine model of C57BL/6J mice infected with Cryptococcus neoformans strain 52D. Our results demonstrate that fungal persistence is associated with an early and sustained expression of IL-10 by lung leukocytes. To examine whether IL-10–mediated immune modulation occurs during the early or late phase of infection, assessments of fungal burden and immunophenotyping were performed on mice treated with anti–IL-10R–blocking Ab at 3, 6, and 9 d postinfection (dpi) (early phase) or at 15, 18, and 21 dpi (late phase). We found that both early and late IL-10 blockade significantly improved fungal clearance within the lung compared with isotype control treatment when assessed 35 dpi. Immunophenotyping identified that IL-10 blockade enhanced several critical effector mechanisms, including increased accumulation of CD4+ T cells and B cells, but not CD8+ T cells; specific increases in the total numbers of Th1 and Th17 cells; and increased accumulation and activation of CD11b+ dendritic cells and exudate macrophages. Importantly, IL-10 blockade effectively abrogated dissemination of C. neoformans to the brain. Collectively, this study identifies early and late cellular and molecular mechanisms through which IL-10 impairs fungal clearance and highlights the therapeutic potential of IL-10 blockade in the treatment of fungal lung infections.
Serine Cluster Phosphorylation Liberates the C-Terminal Helix of IFN Regulatory Factor 7 To Bind Histone Acetyltransferase p300
Authors: Lee Kyoung Jin , Ye Jung Sook , Choe Han , Nam Young Ran , Kim Nari , Lee Uk , Joo Chul Hyun
Published: September 2014

IFN regulatory factor 7 (IRF7) is a major regulator of type I (αβ) IFN secretion. A growing body of evidence shows that IRF7 is involved in a wide variety of pathologic conditions in addition to infections; however, the detailed mechanism of IRF7 transactivation remains elusive. Our current knowledge of IRF7 transactivation is based on studies of IRF3, another major regulator of IFN-β secretion. IRF3 and IRF7 are closely related homologs with high sequence similarity in their C-terminal regions, and both proteins are activated by phosphorylation of a specific serine cluster (SC). Nevertheless, the functional domains of the two proteins are arranged in an inverted manner. We generated a model structure of the IRF7 C-terminal region using homology modeling and used it to guide subsequent functional domain studies. The model structure led to the identification of a tripod-helix structure containing the SC. Based on the model and experimental data, we hypothesized that phosphorylation-mediated IRF7 transactivation is controlled by a tripod-helix structure. Inducible IκB kinase binds a tripod-helix structure. Serial phosphorylation of the SC by the kinase liberates C-terminal helix from an inhibitory hydrophobic pocket. A histone acetyltransferase P300 binds the liberated helix. The difference in the P300 binding sites explains why the domain arrangement of IRF7 is inverted relative to that of IRF3.
Irreducible Tuples Without the Boundary Property
Authors: Chavan Sameer
Published: September 2014

We examine spectral behavior of irreducible tuples that do not admit the boundary property.
In particular, we prove under some mild assumption that the spectral radius of such an m-tuple
(T1,...Tm)must be the operator norm of . We use this simple observation to ensure
the boundary property for an irreducible, essentially normal, joint q-isometry, provided it is not
a joint isometry. We further exhibit a family of reproducing Hilbert C[z1, ...zm]-modules (of which the Drury–Arveson Hilbert module is a prototype) with the property that any two nested unitarily equivalent submodules are indeed equal.
Optimal Seasonal Timing of Oral Azithromycin for Malaria
Authors: Gao Daozhou , Amza Abdou , Nassirou Baidou , Kadri Boubacar , Sippl-Swezey Nicholas , Liu Fengchen , Ackley Sarah F. , Lietman Thomas M. , Porco Travis C.
Published: September 2014

Mass administration of azithromycin for trachoma has been shown to reduce malarial parasitemia. However, the optimal seasonal timing of such distributions for antimalarial benefit has not been established. We performed numerical analyses on a seasonally forced epidemic model (of Ross-Macdonald type) with periodic impulsive annual mass treatment to address this question. We conclude that when azithromycin-based trachoma elimination programs occur in regions of seasonal malaria transmission, such as Niger, the optimal seasonal timing of mass drug administration (MDA) may not occur during the season of maximum transmission.
Dengue Seroprevalence and Risk Factors for Past and Recent Viral Transmission in Venezuela: A Comprehensive Community-Based Study
Authors: Velasco-Salas Zoraida I. , Sierra Gloria M. , Guzmán Diamelis M. , Zambrano Julio , Vivas Daniel , Comach Guillermo , Wilschut Jan C. , Tami Adriana
Published: September 2014

Dengue transmission in Venezuela has become perennial and a major public health problem. The increase in frequency and magnitude of recent epidemics prompted a comprehensive community-based cross-sectional study of 2,014 individuals in high-incidence neighborhoods of Maracay, Venezuela. We found a high seroprevalence (77.4%), with 10% of people experiencing recent infections. Multivariate logistic regression analysis showed that poverty-related socioeconomic factors (place and duration of residence, crowding, household size, and living in a shack) and factors/constraints related to intradomiciliary potential mosquito breeding sites (storing water and used tires) were linked with a greater risk of acquiring a dengue infection. Our results also suggest that transmission occurs mainly at home. The combination of increasingly crowded living conditions, growing population density, precarious homes, and water storage issues caused by enduring problems in public services in Maracay are the most likely factors that determine the permanent dengue transmission and the failure of vector control programs.
Filarial Antigenemia and Loa loa Night Blood Microfilaremia in an Area Without Bancroftian Filariasis in the Democratic Republic of Congo
Authors: Bakajika Didier K. , Nigo Maurice M. , Lotsima Jean Pierre , Masikini Germain A. , Fischer Kerstin , Lloyd Melanie M. , Weil Gary J. , Fischer Peter U.
Published: September 2014

Implementation of mass drug administration for lymphatic filariasis (LF) has been delayed in central Africa because of incomplete mapping and coendemic loiasis. We mapped two regions in eastern Democratic Republic of Congo that were suspected to have LF. Night blood samples were collected from 2,724 subjects in 30 villages. Filarial antigenemia rates by card test exceeded 1% in 28 villages (range = 0–14%). Prevalence rates for large sheathed microfilariae (Mf) ranged from 4% to 40%; Mansonella perstans rates ranged from 22% to 98%. Large Mf were exclusively Loa loa by microscopy, and only 1 of 337 samples tested by quantitative polymerase chain reaction (qPCR) was positive for Wuchereria bancrofti DNA. Filarial antigen positivity was strongly associated with high L. loa Mf counts. Periodicity studies revealed atypical patterns, with no significant diurnal periodicity in some individuals. Thus, methods routinely used for LF mapping may not be reliable in areas in central Africa that are highly endemic for loiasis.
Downslope föhn winds over the Antarctic Peninsula and their effect on the Larsen ice shelves
Authors: Grosvenor D. P. , King J. C. , Choularton T. W. , Lachlan-Cope T.
Published: September 2014

Abstract. Mesoscale model simulations are presented of a westerly föhn event over the Antarctic Peninsula mountain ridge and onto the Larsen C ice shelf, just south of the recently collapsed Larsen B ice shelf. Aircraft observations showed the presence of föhn jets descending near the ice shelf surface with maximum wind speeds at 250–350 m in height. Surface flux measurements suggested that melting was occurring. Simulated profiles of wind speed, temperature and wind direction were very similar to the observations. However, the good match only occurred at a model time corresponding to ~9 h before the aircraft observations were made since the model föhn jets died down after this. This was despite the fact that the model was nudged towards analysis for heights greater than ~1.15 km above the surface. Timing issues aside, the otherwise good comparison between the model and observations gave confidence that the model flow structure was similar to that in reality. Details of the model jet structure are explored and discussed and are found to have ramifications for the placement of automatic weather station (AWS) stations on the ice shelf in order to detect föhn flow. Cross sections of the flow are also examined and were found to compare well to the aircraft measurements. Gravity wave breaking above the mountain crest likely created a~situation similar to hydraulic flow and allowed föhn flow and ice shelf surface warming to occur despite strong upwind blocking, which in previous studies of this region has generally not been considered. Our results therefore suggest that reduced upwind blocking, due to wind speed increases or stability decreases, might not result in an increased likelihood of föhn events over the Antarctic Peninsula, as previously suggested. The surface energy budget of the model during the melting periods showed that the net downwelling short-wave surface flux was the largest contributor to the melting energy, indicating that the cloud clearing effect of föhn events is likely to be the most important factor for increased melting relative to non-föhn days. The results also indicate that the warmth of the föhn jets through sensible heat flux ("SH") may not be critical in causing melting beyond boundary layer stabilisation effects (which may help to prevent cloud cover and suppress loss of heat by convection) and are actually cancelled by latent heat flux ("LH") effects (snow ablation). It was found that ground heat flux ("GRD") was likely to be an important factor when considering the changing surface energy budget for the southern regions of the ice shelf as the climate warms.
Impact of black carbon aerosol over Italian basin valleys: high-resolution measurements along vertical profiles, radiative forcing and heating rate
Authors: Ferrero L. , Castelli M. , Ferrini B. S. , Moscatelli M. , Perrone M. G. , Sangiorgi G. , D'Angelo L. , Rovelli G. , Moroni B. , Scardazza F. , Močnik G. , Bolzacchini E. , Petitta M. , Cappelletti D.
Published: September 2014

Abstract. A systematic study of black carbon (BC) vertical profiles measured at high-resolution over three Italian basin valleys (Terni Valley, Po Valley and Passiria Valley) is presented. BC vertical profiles are scarcely available in literature. The campaign lasted 45 days and resulted in 120 measured vertical profiles. Besides the BC mass concentration, measurements along the vertical profiles also included aerosol size distributions in the optical particle counter range, chemical analysis of filter samples and a full set of meteorological parameters. Using the collected experimental data, we performed calculations of aerosol optical properties along the vertical profiles. The results, validated with AERONET data, were used as inputs to a radiative transfer model (libRadtran). The latter allowed an estimation of vertical profiles of the aerosol direct radiative effect, the atmospheric absorption and the heating rate in the lower troposphere. The present measurements revealed some common behaviors over the studied basin valleys. Specifically, at the mixing height, marked concentration drops of both BC (range: from −48.4 ± 5.3 to −69.1 ± 5.5%) and aerosols (range: from −23.9 ± 4.3 to −46.5 ± 7.3%) were found. The measured percentage decrease of BC was higher than that of aerosols: therefore, the BC aerosol fraction decreased upwards. Correspondingly, both the absorption and scattering coefficients decreased strongly across the mixing layer (range: from −47.6 ± 2.5 to −71.3 ± 3.0% and from −23.5 ± 0.8 to −61.2 ± 3.1%, respectively) resulting in a single-scattering albedo increase along height (range: from +4.9 ± 2.2 to +7.4 ± 1.0%). This behavior influenced the vertical distribution of the aerosol direct radiative effect and of the heating rate. In this respect, the highest atmospheric absorption of radiation was predicted below the mixing height (~ 2–3 times larger than above it) resulting in a heating rate characterized by a vertical negative gradient (range: from −2.6 ± 0.2 to −8.3 ± 1.2 K day−1 km−1). In conclusion, the present results suggest that the BC below the mixing height has the potential to promote a negative feedback on the atmospheric stability over basin valleys, weakening the ground-based thermal inversions and increasing the dispersal conditions.
Aqueous-phase photooxidation of levoglucosan – a mechanistic study using aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS)
Authors: Zhao R. , Mungall E. L. , Lee A. K. Y. , Aljawhary D. , Abbatt J. P. D.
Published: September 2014

Abstract. Levoglucosan (LG) is a widely employed tracer for biomass burning (BB). Recent studies have shown that LG can react rapidly with hydroxyl (OH) radicals in the aqueous phase despite many mass balance receptor models assuming it to be inert during atmospheric transport. In the current study, aqueous-phase photooxidation of LG by OH radicals was performed in the laboratory. The reaction kinetics and products were monitored by aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS). Approximately 50 reaction products were detected by the Aerosol ToF-CIMS during the photooxidation experiments, representing one of the most detailed product studies yet performed. By following the evolution of mass defects of product peaks, unique trends of adding oxygen (+O) and removing hydrogen (−2H) were observed among the products detected, providing useful information for determining potential reaction mechanisms and sequences. Additionally, bond-scission reactions take place, leading to reaction intermediates with lower carbon numbers. We introduce a data analysis framework where the average oxidation state (OSc) is plotted against a novel molecular property: double-bond-equivalence-to-carbon ratio (DBE/#C). The trajectory of LG photooxidation on this plot suggests formation of polycarbonyl intermediates and their subsequent conversion to carboxylic acids as a general reaction trend. We also determined the rate constant of LG with OH radicals at room temperature to be 1.08 ± 0.16 × 109 M−1 s−1. By coupling an aerosol mass spectrometer (AMS) to the system, we observed a rapid decay of the mass fraction of organic signals at mass-to-charge ratio 60 (f60), corresponding closely to the LG decay monitored by the Aerosol ToF-CIMS. The trajectory of LG photooxidation on a f44–f60 correlation plot matched closely to literature field measurement data. This implies that aqueous-phase photooxidation might be partially contributing to aging of BB particles in the ambient atmosphere.
Simulation of the isotopic composition of stratospheric water vapour – Part 1: Description and evaluation of the EMAC model
Authors: Eichinger R. , Jöckel P. , Brinkop S. , Werner M. , Lossow S.
Published: September 2014

Abstract. This modelling study aims on an improved understanding of the processes, that determine the water vapour budget in the stratosphere by means of the investigation of water isotope ratios. At first, a separate hydrological cycle has been introduced into the chemistry-climate model EMAC, including the water isotopologues HDO and H218O and their physical fractionation processes. Additionally an explicit computation of the contribution of methane oxidation to HDO has been incorporated. The model expansions allow detailed analyses of water vapour and its isotope ratio with respect to deuterium throughout the stratosphere and in the transition region to the troposphere. In order to assure the correct representation of the water isotopologues in the model's hydrological cycle, the expanded system has been evaluated in several steps. The physical fractionation effects have been evaluated by comparison of the simulated isotopic composition of precipitation with measurements from a ground-based network (GNIP) and with the results from the isotopologue-enabled general circulation model ECHAM5-wiso. The model's representation of the chemical HDO precursor CH3D in the stratosphere has been confirmed by a comparison with chemical transport models (CHEM1D, CHEM2D) and measurements from radiosonde flights. Finally, the simulated stratospheric HDO and the isotopic composition of water vapour have been evaluated, with respect to retrievals from three different satellite instruments (MIPAS, ACE-FTS, SMR). Discrepancies in stratospheric water vapour isotope ratios between two of the three satellite retrievals can now partly be explained.
The stratospheric response to external factors based on MERRA data using linear multivariate linear regression analysis
Authors: Kozubek M. , Rozanov E. , Krizan P.
Published: September 2014

Abstract. The stratosphere is influenced by many external forcings (natural or anthropogenic). There are many studies which are focused on this problem and that is why we can compare our results with them. This study is focused on the variability and trends of temperature and circulation characteristics (zonal and meridional wind component) in connection with different phenomena variation in the stratosphere and lower mesosphere. We consider the interactions between the troposphere–stratosphere-lower mesosphere system and external and internal phenomena, e.g. solar cycle, QBO, NAO or ENSO using multiple linear techniques. The analysis was applied to the period 1979–2012 based on the current reanalysis data, mainly the MERRA reanalysis dataset (Modern Era Retrospective-analysis for Research and Applications) for pressure levels: 1000–0.1 hPa. We do not find a strong temperature signal for solar flux over the tropics about 30 hPa (ERA-40 results) but the strong positive signal has been observed near stratopause almost in the whole analyzed area. This could indicate that solar forcing is not represented well in the higher pressure levels in MERRA. The analysis of ENSO and ENSO Modoki shows that we should take into account more than one ENSO index for similar analysis. Previous studies show that the volcanic activity is important parameter. The signal of volcanic activity in MERRA is very weak and insignificant.
On the man-made contamination on ULF measurements: evidence for disturbances related to an electrified DC railway
Authors: Villante U. , Piancatelli A. , Palangio P.
Published: September 2014

Abstract. An analysis of measurements performed at L'Aquila (Italy) during a deep minimum of solar and magnetospheric activity (2008–2010) allowed for the evaluation of possible contamination of the ultralow-frequency (ULF) spectrum (f ≈ 1–500 mHz) from artificial disturbances, practically in absence of natural signals. In addition, the city evacuation and the interruption of all industrial and social activities after the strong earthquake of 6 April 2009 allowed also for the examination of possible changes of the contamination level under remarkably changed environmental conditions. Our analysis reveals a persistent, season-independent, artificial signal, with the same characteristics in the H and Z components, that affects during daytime hours the entire spectrum; such contamination persists after the city evacuation. We speculate that the DC electrified railway (located ≈ 33 km from the Geomagnetic Observatory of L'Aquila, it maintained the same train traffic after the earthquake) is responsible for the observed disturbances.