Catching a Viral Video

The sharing and re-sharing of videos on social sites, blogs e-mail, and other means has given rise to the phenomenon of viral videos - videos that become popular through internet sharing. In this paper we seek to better understand viral videos on YouTube by analyzing sharing and its relationship to video popularity using millions of YouTube videos. The socialness of a video is quantified by classifying the referrer sources for video views as social (e.g. an emailed link, Facebook referral) or non-social (e.g. a link from related videos). We find that viewership patterns of highly social videos are very different from less social videos. For example, the highly social videos rise to, and fall from, their peak popularity more quickly than less social videos. We also find that not all highly social videos become popular, and not all popular videos are highly social. By using our insights on viral videos we are able develop a method for ranking blogs and websites on their ability to spread viral videos

Rivers of the Anthropocene Phase 1: A Comparative Study of the Tyne and Ohio River Valleys

poster abstractThe Rivers of the Anthropocene project is an international effort. Our part is an attempt to determine flood frequency and land use by American Indian tribes of the Mississippian Culture along the Ohio River. Methodologically, we will measure the physical and geochemical properties of lacustrine sediments recovered from Hovey Lake, a flood plane lake located on the Ohio River in southwestern Indiana. Sediment cores taken from Hovey Lake are being measured for bulk density and loss-on-ignition tests to determine organic composition by weight. Magnetic susceptibility is also being measured to determine variations in the delivery of terrestrial material (e.g. from flooding/land erosion) to the lake. Land use will be evaluated by measuring variations in the elemental abundance and isotopic composition of nitrogen and organic carbon, which has been used in the past to identify prehistoric land use. Here we present the initial results of our ongoing work, including sedimentological and chronological data. Ultimately, these data will help bring together historical records, geochemical records, and other contributions from scientists around the world in our attempt to better understand mankind’s impact on our environment

The Relationship Between Nonprofit Capacity Building, Organizational Learning And Organizational Effectiveness: A Case Study Of Strengthening Communities Fund Program In Central Florida

Nonprofit capacity building programs and program activities positively influence perceived organizational effectiveness. Being able to link nonprofit capacity building to organizational effectiveness is a paramount concern for both nonprofits seeking capacity building programming and those entities, be it foundations or government that fund capacity building initiatives and programs. Therefore being able to link nonprofit capacity building to organizational effectiveness and higher performance is crucial to ensure that both nonprofit organizations and funders continue to pursue and support capacity building programming. Through an examination of the developing hollow state and the resulting nonprofit capacity disparity this study demonstrates the purposeful need for the continuation of nonprofit capacity building programming and the support of such programming through outside private foundation and government funding. Using a conceptual model developed from the literature on organizational learning and change this study examines the impact of capacity building programming, programming activities, organizational learning theory and perceived organizational effectiveness. The influence of the type of capacity building programming, i.e. traditional workshop and traditional workshop plus technical and financial assistance is investigated through the use of quantitative and qualitative methods. Specifically the quantitative methods utilized were descriptive including bi-variate correlation analysis, paired and independent T-tests, ANOVA and multiple regression. The qualitative analysis including examining open-ended survey question responses from two pre-post capacity building intervention surveys and one post program survey and the analysis of comments made in 10 focus groups. The influence of capacity building programming iv activities, i.e. organizational development, organizational program development, organizational collaboration and organizational leadership is investigated through the use of multiple regression and qualitative analysis. This study uses pre-, post-test survey data from a total of 43 nonprofit organizations that participated in the Strengthening Communities Fund in Central Florida Program, managed by the Center for Public and Nonprofit Management at the University of Central Florida. The two year program was offered in two identical 10 month cycles. Pre- and post-test data were collected from 23 participant organizations in Cycle 1 and 20 in Cycle 2. This study sought to identify the nonprofit capacity building programming modality and programming activities that contributed most to perceived organizational effectiveness. According to the findings, nonprofit organizations seeking capacity building and funders looking to support capacity building programs should look to programs that offer activities that increase organizational leadership capacity and organizational program development. Increasing organizational leadership capacity and organizational program development contributes most to perceived organizational effectiveness. This study did not find support to recommend one particular capacity building training modality over another. Regardless of the method of capacity building program delivery, i.e. workshop and/or technical and financial assistance, programs which build organizational leadership capacity and organizational program development will greatly influence the perceived organizational effectiveness of the capacity building participant organizations

The antimicrobial polymer PHMB enters cells and selectively condenses bacterial chromosomes

To combat infection and antimicrobial resistance, it is helpful to elucidate drug mechanism(s) of action. Here we examined how the widely used antimicrobial polyhexamethylene biguanide (PHMB) kills bacteria selectively over host cells. Contrary to the accepted model of microbial membrane disruption by PHMB, we observed cell entry into a range of bacterial species, and treated bacteria displayed cell division arrest and chromosome condensation, suggesting DNA binding as an alternative antimicrobial mechanism. A DNA-level mechanism was confirmed by observations that PHMB formed nanoparticles when mixed with isolated bacterial chromosomal DNA and its effects on growth were suppressed by pairwise combination with the DNA binding ligand Hoechst 33258. PHMB also entered mammalian cells, but was trapped within endosomes and excluded from nuclei. Therefore, PHMB displays differential access to bacterial and mammalian cellular DNA and selectively binds and condenses bacterial chromosomes. Because acquired resistance to PHMB has not been reported, selective chromosome condensation provides an unanticipated paradigm for antimicrobial action that may not succumb to resistance

Warm-based basal sediment entrainment and far-field Pleistocene origin evidenced in central Transantarctic blue ice through stable isotopes and internal structures

Stable isotopes of water (δ18O and δ2H) were measured in the debris-laden ice underlying an Antarctic blue ice moraine, and in adjoining Law Glacier in the central Transantarctic Mountains. Air bubble content and morphology were assessed in shallow ice core samples. Stable isotope measurements plot either on the meteoric waterline or are enriched from it. The data cluster in two groups: the ice underlying the moraine has a δ2H:δ18O slope of 5.35 ± 0.92; ice from adjoining portions of Law Glacier has a slope of 6.69 ± 1.39. This enrichment pattern suggests the moraine's underlying blue ice entrained sediment through refreezing processes acting in an open system. Glaciological conditions favorable to warm-based sediment entrainment occur 30–50 km upstream. Basal melting and refreezing are further evidenced by abundant vapor figures formed from internal melting of the ice crystals. Both the moraine ice and Law Glacier are sufficiently depleted of heavy isotopes that their ice cannot be sourced locally, but instead must be derived from far-field interior regions of the higher polar plateau. Modeled ice flow speeds suggest the ice must be at least 80 ka old, with Law Glacier's ice possibly dating to OIS 5 and moraine ice older still

Estimating Nuisance Parameters in Inverse Problems

Many inverse problems include nuisance parameters which, while not of direct interest, are required to recover primary parameters. Structure present in these problems allows efficient optimization strategies - a well known example is variable projection, where nonlinear least squares problems which are linear in some parameters can be very efficiently optimized. In this paper, we extend the idea of projecting out a subset over the variables to a broad class of maximum likelihood (ML) and maximum a posteriori likelihood (MAP) problems with nuisance parameters, such as variance or degrees of freedom. As a result, we are able to incorporate nuisance parameter estimation into large-scale constrained and unconstrained inverse problem formulations. We apply the approach to a variety of problems, including estimation of unknown variance parameters in the Gaussian model, degree of freedom (d.o.f.) parameter estimation in the context of robust inverse problems, automatic calibration, and optimal experimental design. Using numerical examples, we demonstrate improvement in recovery of primary parameters for several large- scale inverse problems. The proposed approach is compatible with a wide variety of algorithms and formulations, and its implementation requires only minor modifications to existing algorithms.Comment: 16 pages, 5 figure