Molluscs from a shallow-water whale-fall and their affinities with adjacent benthic communities on the Swedish west coast

We conducted a species-level study of molluscs associated with a 5-m long carcass of a minke whale at a depth of 125 m in the Kosterfjord (North Sea, Sweden). The whale-fall community was quantitatively compared with the community commonly living in the surrounding soft-bottom sediments. Five years after the deployment of the dead whale at the sea floor, the sediments around the carcass were dominated by the bivalve Thyasira sarsi, which is known to contain endosymbiotic sulphur-oxidizing bacteria, while background sediments were dominated by another thyasirid, T. equalis, less dependent on chemosynthesis for its nutrition. The Kosterfjord samples were further compared at the species level with mollusc abundance data derived from the literature, including samples from different marine settings of the west coast of Sweden (active methane seep, fjords, coastal and open marine environments). The results show high similarity between the Kosterfjord whale-fall community and the community that developed in one of the Swedish fjords (Gullmar Fjord) during hypoxic conditions. This study indicates that at shallow-water whale-falls, the sulphophilic stage of the ecological succession is characterized by generalist chemosynthetic bivalves commonly living in organic-rich, sulphidic environments. © 2014 Taylor & Francis

Signed Graphs with Maximum Nullity at Most Two

A signed graph is an ordered pair (G,Σ), where G = (V, E) is a graph and Σ ⊆ E. The edges in Σ are called odd, and the edges in E \ Σ are called even. The family of matrices S(G,Σ) is defined such that if [ai,j] = A ∈ S(G,Σ), then ai,j \u3c 0 if there is at least one edge between i and j and if all edges between i and j are even; ai,j \u3e 0 if there is at least one edge between i and j and if all edges between i and j are odd; ai,j ∈ R if there is at least one even edge and at least one odd edge between i and j; and ai,j = 0 if there are no edges between i and j. The maximum nullity of a signed graph M(G,Σ) is the largest corank(A) for A ∈ S(G, Σ). The matrix A ∈ S(G, Σ) has the Strong Arnold Property with respect to (G,Σ) if X = 0 is the only matrix such that AX = 0, and xi,j = 0 if i is adjacent to j or i = j. The stable maximum nullity of a signed graph ξ(G,Σ) is the largest corank(A) for A ∈ S(G,Σ) where A has the Strong Arnold Property. Here, we present a combinatorial characterization of signed graphs with maximum nullity at most two, extending a result of Johnson, Loewy, and Smith. We also find the forbidden minors for signed graphs with stable maximum nullity at most two, extending a result of Hogben and van der Holst. We generalize the notion of zero forcing to signed graphs. We find the zero forcing number of signed graphs with maximum nullity at most two, extending a result of Row

Information Diffusion Power of Political Party Twitter Accounts During Japan's 2017 Election

In modern election campaigns, political parties utilize social media to advertise their policies and candidates and to communicate to electorates. In Japan's latest general election in 2017, the 48th general election for the Lower House, social media, especially Twitter, was actively used. In this paper, we perform a detailed analysis of social graphs and users who retweeted tweets of political parties during the election. Our aim is to obtain accurate information regarding the diffusion power for each party rather than just the number of followers. The results indicate that a user following a user who follows a political party account tended to also follow the account. This means that it does not increase diversity because users who follow each other tend to share similar values. We also find that followers of a specific party frequently retweeted the tweets. However, since users following the user who follow a political party account are not diverse, political parties delivered the information only to a few political detachment users.Comment: The 10th International Conference on Social Informatics (SocInfo 2018

Multivariate adaptive regression splines for estimating riverine constituent concentrations

Regression-based methods are commonly used for riverine constituent concentration/flux estimation, which is essential for guiding water quality protection practices and environmental decision making. This paper developed a multivariate adaptive regression splines model for estimating riverine constituent concentrations (MARS-EC). The process, interpretability and flexibility of the MARS-EC modelling approach, was demonstrated for total nitrogen in the Patuxent River, a major river input to Chesapeake Bay. Model accuracy and uncertainty of the MARS-EC approach was further analysed using nitrate plus nitrite datasets from eight tributary rivers to Chesapeake Bay. Results showed that the MARS-EC approach integrated the advantages of both parametric and nonparametric regression methods, and model accuracy was demonstrated to be superior to the traditionally used ESTIMATOR model. MARS-EC is flexible and allows consideration of auxiliary variables; the variables and interactions can be selected automatically. MARS-EC does not constrain concentration-predictor curves to be constant but rather is able to identify shifts in these curves from mathematical expressions and visual graphics. The MARS-EC approach provides an effective and complementary tool along with existing approaches for estimating riverine constituent concentrations

Evaluation and proposed revisions of criteria for andosols in the world reference base for soil resources

The proposed criteria for andosol classification in the World Reference Base (WRB) of Soil Resources were evaluated using the Tohoku University World Andosol Database (TUWAD). The WRB proposal defines a diagnostic andic horizon comprised of vitr-andic, alu-andic, and sil-andic subtypes, and eight second level soil units. Several notable refinements to the WRB criteria were apparent from evaluation of soil properties from TUWAD and are proposed as revised criteria. Our analysis indicated that the most effective criteria for differentiating the andic horizon were glass content, phosphate retention, oxalate extractable Al and Fe, pyrophosphate-extractable Al, and bulk density. The vitr-andic horizon is distinguished by its low degree of weathering, evident from its low oxalate extractable Al and Fe, low P retention, and high glass content. The ratio of pyrophosphate to oxalate extractable Al is used to separate andic horizons dominated by Al-humus, complexes (alu-andic, Al(p)/Al(o) greater or equal than 0.5), from those dominated by allophanic materials (sil-andic, Al(p)/Al(o) < 0.5). When Al(p) data are not availabe, the Si(o) value of 0.6 could be used as an approximate criteria. We also propose revisions to the nine second level soil units based on the dominant pedogenic processes occurring in andosols : non-crystalline material formation and organic matter accumulation. These soil units are based on the degree of weathering (oxalate extractable Al, Fe, glass content), the dominant weathering agent (organic acids vs. carbonic acid), type (melanic or fulvic) and quantity of organic matter, and high 1.5 MPa water-holding capacity. The revised criteria determined by this study effectively differentiate andosols based on their dominant pedogenic processes, and the relationship or soil properties to productivity and utilization. (Résumé d'auteur

Confronting globalisation: Learning from intercontinental collaboration

Higher education institutions are responding to globalisation in various ways. This study describes and analyses challenges encountered in a recent case of global collaboration between four universities on different continents in developing a web-based master's program. The key issue was how to develop programs in a way that is fair for the different countries involved. The focus of the paper is on tensions between local and national contexts, rules and resources and the creation of a common global program. 'Agency', 'structure' and 'frame factor' are used as analytical concepts to help understand the dynamics of the collaboration and the character of the program

Dependence of Maximum Trappable Field on Superconducting Nb3Sn Cylinder Wall Thickness

Uniform dipole magnetic fields from 1.9 to 22.4 kOe were permanently trapped, with high fidelity to the original field, transversely to the axes of hollow Nb3Sn superconducting cylinders. These cylinders were constructed by helically wrapping multiple layers of superconducting ribbon around a mandrel. This is the highest field yet trapped, the first time trapping has been reported in such helically wound taped cylinders, and the first time the maximum trappable field has been experimentally determined as a function of cylinder wall thickness.Comment: 8 pages, 4 figures, 1 table. PACS numbers: 74.60.Ge, 74.70.Ps, 41.10.Fs, 85.25.+

The Southern Movement in Yemen

During the past year, people of the former South Yemen Republic have joined a popular movement demanding fair rule and equal citizenship against which the Yemeni government has taken harsh methods. While the western world concentrates on Al-Qaida and kidnapped tourists, the movement has taken a visible presence on the Internet, which offers a whole new platform for political protest

Radar detection of a localized 1.4 Hz pulsation in auroral plasma, simultaneous with pulsating optical emissions, during a substorm

Many pulsating phenomena are associated with the auroral substorm. It has been considered that some of these phenomena involve kilometer-scale Alfvén waves coupling the magnetosphere and ionosphere. Electric field oscillations at the altitude of the ionosphere are a signature of such wave activity that could distinguish it from other sources of auroral particle precipitation, which may be simply tracers of magnetospheric activity. Therefore, a ground based diagnostic of kilometer-scale oscillating electric fields would be a valuable tool in the study of pulsations and the auroral substorm. In this study we attempt to develop such a tool in the Poker Flat incoherent scatter radar (PFISR). The central result is a statistically significant detection of a 1.4 Hz electric field oscillation associated with a similar oscillating optical emission, during the recovery phase of a substorm. The optical emissions also contain a bright, lower frequency (0.2 Hz) pulsation that does not show up in the radar backscatter. The fact that higher frequency oscillations are detected by the radar, whereas the bright, lower frequency optical pulsation is not detected by the radar, serves to strengthen a theoretical argument that the radar is sensitive to oscillating electric fields, but not to oscillating particle precipitation. Although it is difficult to make conclusions as to the physical mechanism, we do not find evidence for a plane-wave-like Alfvén wave; the detected structure is evident in only two of five adjacent beams. We emphasize that this is a new application for ISR, and that corroborating results are needed

Utah\u27s Own Habitat Guidelines for Sage-Grouse

Those living and working within western North America’s sagebrush landscapes have most likely been exposed to sage-grouse issues for many years now and may have felt anxiety concerning the potential impacts that could result from implementing conservation measures designed to help this iconic species persist. Society’s challenge to seek the delicate balance between the conservation of nature and the growth related to human endeavors exemplifies the need to use the best available science as we move forward. Representative information, especially at the landscape level related to sage-grouse, has been hard to come by. However, due to the vast amount of research conducted within Utah’s sage-grouse populations and the yeoman efforts carried out by many individuals, Utah researchers have had the unique opportunity to quantitatively assess sage-grouse habitat characteristics across the vast variation in vegetation communities in most of Utah’s sage-grouse populations. From this assessment, representative habitat guidelines have been developed to help all affected parties responsibly move sage-grouse conservation forward in Utah