Investigating the Impact of the Blogsphere: Using PageRank to Determine the Distribution of Attention

Much has been written in recent years about the blogosphere and its impact on political, educational and scientific debates. Lately the issue has received significant attention from the industry. As the blogosphere continues to grow, even doubling its size every six months, this paper investigates its apparent impact on the overall Web itself. We use the popular Google PageRank algorithm which employs a model of Web used to measure the distribution of user attention across sites in the blogosphere. The paper is based on an analysis of the PageRank distribution for 8.8 million blogs in 2005 and 2006. This paper addresses the following key questions: How is PageRank distributed across the blogosphere? Does it indicate the existence of measurable, visible effects of blogs on the overall mediasphere? Can we compare the distribution of attention to blogs as characterised by the PageRank with the situation for other forms of Web content? Has there been a growth in the impact of the blogosphere on the Web over the two years analysed here? Finally, it will also be necessary to examine the limitations of a PageRank-centred approach

Web 2.0 und SOA — verwandte Konzepte?

Zusammenfassung: Eine neue Klasse von Internetapplikationen wie interaktive Enzyklopädien, Blogs oder auch sogenannte Mashups hat während der letzten Jahre groβe Verbreitung gefunden und wird oft unter dem Begriff Web 2.0 zusammengefasst. Ein Thema, das seit kurzer Zeit diskutiert wird, ist der Zusammenhang zwischen Web 2.0 und dem Konzept der serviceorientierten Architektur (SOA). Der Gedanke der Wiederverwendbarkeit und des Verbergens von Komplexität, aber auch das lose Koppeln verschiedener Dienste hat die wissenschaftliche Gemeinschaft angeregt, Gemeinsamkeiten zwischen Web 2.0 und SOA herauszuarbeiten. In dieser Arbeit werden Anwendungsbeispiele der beiden Konzepte sowohl aus technischer als auch aus betriebswirtschaftlicher Perspektive untersucht und auf der Basis von sieben Kriterien kontrastiert. Die detaillierte Analyse soll dabei Unterschiede wie auch Gemeinsamkeiten aufdecken und schlieβlich einen Ausblick auf zukünftige Applikationen, die auf Technologien und Gestaltungsprinzipien von sowohl Web 2.0 als auch SOA aufbauen, gebe

Mapping the Australian Twittersphere

This paper presents the first outcomes of a large-scale project to comprehensively map the follower/followee relationships between public accounts in the Australian Twittersphere. Using custom network crawling technology, we have conducted a snowball crawl of Twitter accounts operated by Australian users to identify more than one million users and map their interconnections. In itself the map provides an overview of the major clusters of densely interlinked users, centred largely around shared topics of interest (from politics through arts to sport) and/or sociodemographic factors (geographic location, age groups); additionally, in combination with our investigation of participation patterns in specific thematic hashtag discussions on Twitter (from #spill for the 2010 Rudd/Gillard leadership challenge to #qldfloods for the January 2011 floods in southeast Queensland), the map enables us to examine which areas of the underlying follower/followee network are activated in the discussion of specific current topics. Our work, conducted as part of a three-year ARC Discovery project investigating public communication through social media in Australia, demonstrates the possibilities inherent in the current ‘computational turn’ (Berry 2010) in Digital Humanities, as well as adding to the development and critical examination of methodologies for dealing with 'big data' (boyd and Crawford 2011). Our map of the Twittersphere is the first of its kind for the Australian part of the global Twitter network and provides the first independent and scholarly estimation of the size of the total Australian Twitter population. Our tools and methods for doing Twitter research, released under Creative Commons licences through our project website, provide the basis for replicable and verifiable Digital Humanities research on the processes of public communication which take place through this important social network.Australian Academy of the Humanities; the ANU College of Arts and Social Science

Dilemmas and Trade-Offs in Peacemaking: A Framework for Navigating Difficult Decisions

This article focuses on the dilemmas and trade-offs that third parties face when mediating violent political conflicts. Should they ignore human rights violations because pushing the issue could jeopardize relationships with political actors who grant access for humanitarian aid? Will bringing moderates and hardliners together help the peace process or radicalize moderate actors? What should dialogue facilitators do when the act of identifying non-mainstream groups to be included into dialogue increases division and polarization? The activity of peacemaking is inherently characterized by such process and strategy dilemmas where two equally compulsory imperatives seem not to be attainable at the same time. The article proposes a framework to break out of either-or thinking in these situations. We argue that: 1) making oneself aware of how a decision is perceived, and 2) systematically exploring a set of different strategies for creating new unexpected options helps to ease these decisions and avoid rotten compromises. The model reworks and combines existing problem-solving strategies to create a new explorative option generation approach to peacemaking dilemmas and trade-offs. Some of these strategies, such as sequencing and incrementalization, are already well-established in peacemaking. Others, such as compartmentalization and utilization, are rather unconsciously used. All identified strategies, however, are not yet systematically employed to manage third parties’ own dilemmas and trade-offs. Under the suggested framework, these strategies can act in complement to synthesize creativity and strategic thinking with surprising ease. Using examples from the authors’ peacemaking activities and observations in Myanmar, Thailand, and Ukraine, the article demonstrates the real-world benefits of the framework in terms of decision assessment and optional thinking

Complications and clinical outcome of hepatic artery embolisation in patients with hereditary haemorrhagic telangiectasia

BACKGROUND: Hepatic artery embolisation (HAE) in patients with hereditary haemorrhagic telangiectasia (HHT) is controversial because of the associated complications and unproven long-term benefit. We present our results in 20 such patients over a time span of 17 years. METHODS: Staged HAE was performed using polyvinyl alcohol (PVA) particles and coils. Complications, clinical symptoms and cardiac output were assessed before and after therapy as well as at the end of follow-up (median 92 months, range 26–208 months). RESULTS: Two patients died within 30 days following HAE (10 %). Four further deaths resulted from causes unrelated to HAE. Ischaemic cholangitis, cholecystitis and focal hepatic necrosis with biliary sepsis necessitated re-intervention in four patients. In all but one patient, clinical symptoms resolved with mean cardiac output falling from 11.84 ± 3.22 l/min pre-treatment to 8.13 ± 2.67 l/min at the end of follow-up (P < 0.001). One patient required liver transplantation for de novo symptoms of portal hypertension 4 years after primary symptoms had been cured by HAE. CONCLUSION: The 30-day mortality of HAE in patients with HHT is 10 %. The rate of complications requiring re-intervention is 20 %. Clinical response at long-term follow-up is satisfactory. KEY POINTS: • Hepatic artery embolisation (HAE) in hereditary haemorrhagic telangiectasia (HHT) provides long-term benefit. • Mortalities of HAE and liver transplantation in HHT patients are comparable. • In HHT, complications of HAE are lower than those of liver transplantation. • Complications of HAE can be further reduced by refinement of technique. • Complications include ischaemic cholangitis, hepatic necrosis, biliary sepsis and death

B Cell Depletion Reduces the Number of Autoreactive T Helper Cells and Prevents Glucose-6-Phosphate Isomerase-Induced Arthritis

The therapeutic benefit of B cell depletion in patients with rheumatoid arthritis has provided proof of concept that B cells are relevant for the pathogenesis of arthritis. It remains unknown which B cell effector functions contribute to the induction or chronification of arthritis. We studied the clinical and immunological effects of B cell depletion in glucose-6-phosphate isomerase-induced arthritis. We targeted CD22 to deplete B cells. Mice were depleted of B cells before or after immunization with glucose-6-phosphate isomerase (G6PI). The clinical and histological effects were studied. G6PI-specific antibody responses were measured by ELISA. G6PI-specific T helper (Th) cell responses were assayed by polychromatic flow cytometry. B cell depletion prior to G6PI-immunization prevented arthritis. B cell depletion after immunization ameliorated arthritis, whereas B cell depletion in arthritic mice was ineffective. Transfer of antibodies from arthritic mice into B cell depleted recipients did not reconstitute arthritis. B cell depleted mice harbored much fewer G6PI-specific Th cells than control animals. B cell depletion prevents but does not cure G6PI-induced arthritis. Arthritis prevention upon B cell depletion is associated with a drastic reduction in the number of G6PI-specific effector Th cells

HIV-1 Vpu is a potent transcriptional suppressor of NF-κB-elicited antiviral immune responses

Many viral pathogens target innate sensing cascades and/or cellular transcription factors to suppress antiviral immune responses. Here, we show that the accessory viral protein U (Vpu) of HIV-1 exerts broad immunosuppressive effects by inhibiting activation of the transcription factor NF-κB. Global transcriptional profiling of infected CD4 +T cells revealed that vpu-deficient HIV-1 strains induce substantially stronger immune responses than the respective wild type viruses. Gene set enrichment analyses and cytokine arrays showed that Vpu suppresses the expression of NF-κB targets including interferons and restriction factors. Mutational analyses demonstrated that this immunosuppressive activity of Vpu is independent of its ability to counteract the restriction factor and innate sensor tetherin. However, Vpu-mediated inhibition of immune activation required an arginine residue in the cytoplasmic domain that is critical for blocking NF-κB signaling downstream of tetherin. In summary, our findings demonstrate that HIV-1 Vpu potently suppresses NF-κB-elicited antiviral immune responses at the transcriptional level

The BARRIERS scale -- the barriers to research utilization scale: A systematic review

<p>Abstract</p> <p>Background</p> <p>A commonly recommended strategy for increasing research use in clinical practice is to identify barriers to change and then tailor interventions to overcome the identified barriers. In nursing, the BARRIERS scale has been used extensively to identify barriers to research utilization.</p> <p>Aim and objectives</p> <p>The aim of this systematic review was to examine the state of knowledge resulting from use of the BARRIERS scale and to make recommendations about future use of the scale. The following objectives were addressed: To examine how the scale has been modified, to examine its psychometric properties, to determine the main barriers (and whether they varied over time and geographic locations), and to identify associations between nurses' reported barriers and reported research use.</p> <p>Methods</p> <p>Medline (1991 to September 2009) and CINHAL (1991 to September 2009) were searched for published research, and ProQuest^®digital dissertations were searched for unpublished dissertations using the BARRIERS scale. Inclusion criteria were: studies using the BARRIERS scale in its entirety and where the sample was nurses. Two authors independently assessed the study quality and extracted the data. Descriptive and inferential statistics were used.</p> <p>Results</p> <p>Sixty-three studies were included, with most using a cross-sectional design. Not one study used the scale for tailoring interventions to overcome identified barriers. The main barriers reported were related to the setting, and the presentation of research findings. Overall, identified barriers were consistent over time and across geographic locations, despite varying sample size, response rate, study setting, and assessment of study quality. Few studies reported associations between reported research use and perceptions of barriers to research utilization.</p> <p>Conclusions</p> <p>The BARRIERS scale is a nonspecific tool for identifying general barriers to research utilization. The scale is reliable as reflected in assessments of internal consistency. The validity of the scale, however, is doubtful. There is no evidence that it is a useful tool for planning implementation interventions. We recommend that no further descriptive studies using the BARRIERS scale be undertaken. Barriers need to be measured specific to the particular context of implementation and the intended evidence to be implemented.</p