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

Co-existing structures from high and low energy precipitation in fine scale aurora

High resolution multi-monochromatic measurements of auroral emissions have revealed the first optical evidence of coexisting small-scale auroral features resulting from separate high and low energy populations of precipitating electrons on the same field line. The features exhibit completely separate motion and morphology. From emission ratios and ion chemistry modeling, the average energy and energy flux of the precipitation is estimated. The high energy precipitation is found to form large pulsating patches of 0.1 Hz with a 3 Hz modulation, and non-pulsating co-existing discrete auroral filaments. The low energy precipitation is observed simultaneously on the same field line as discrete filaments with no pulsation. The simultaneous structures do not interact, and they drift with different speeds in different directions. We suggest that the high and low energy electron populations are accelerated by separate mechanisms, at different distances from earth. The small scale structures could be caused by local instabilities above the ionosphere

Dynamics of Density Cavities Generated by Frictional Heating: Formation, Distortion, and Instability

A simulation study of the generation and evolution of mesoscale density cavities in the polar ionosphere is conducted using a time-dependent, nonlinear, quasi-electrostatic model. The model demonstrates that density cavities, generated by frictional heating, can form in as little as 90 s due to strong electric fields of ∼120 mV/m, which are sometimes observed near auroral zone and polar cap arcs. Asymmetric density cavity features and strong plasma density gradients perpendicular to the geomagnetic field are naturally generated as a consequence of the strong convection and finite extent of the auroral feature. The walls of the auroral density cavities are shown to be susceptible to large-scale distortion and gradient-drift instability, hence indicating that arc-related regions of frictional heating may be a source of polar ionospheric density irregularities

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.+

Energy and flux variations across thin auroral arcs

Two discrete auroral arc filaments, with widths of less than 1 km, have been analysed using multi-station, multi-monochromatic optical observations from small and medium field-of-view imagers and the EISCAT radar. The energy and flux of the precipitating electrons, volume emission rates and local electric fields in the ionosphere have been determined at high temporal (up to 30 Hz) and spatial (down to tens of metres) resolution. A new time-dependent inversion model is used to derive energy spectra from EISCAT electron density profiles. The energy and flux are also derived independently from optical emissions combined with ion-chemistry modelling, and a good agreement is found. A robust method to obtain detailed 2-D maps of the average energy and number flux of small scale aurora is presented. The arcs are stretched in the north-south direction, and the lowest energies are found on the western, leading edges of the arcs. The large ionospheric electric fields (250 mV m?1) found from tristatic radar measurements are evidence of strong currents associated with the region close to the optical arcs. The different data sets indicate that the arcs appear on the boundaries between regions with different average energy of diffuse precipitation, caused by pitch-angle scattering. The two thin arcs on these boundaries are found to be related to an increase in number flux (and thus increased energy flux) without an increase in energ

Conflicting discourses of church youths on masculinity and sexuality in the context of HIV in Kinshasa, Democratic Republic of Congo

Masculinity studies are fairly new and young churchgoers are an under-researched group in the current Congolese church context. In response to this knowledge gap, this paper attempts to explore discourses of young  churchgoers from deprived areas of Kinshasa regarding masculinity and sexuality in the era of HIV. A series of 16 semi-structured interviews were conducted with unmarried young churchgoers from the Salvation Army, Protestant and Revival churches. The interviews were tape-recorded, transcribed verbatim and analysed using discourse analysis. Five main discourses emerged: ‘we are aware of the church message on sex’, ‘young men need sex’, ‘young women need money’, ‘to use or not to use condoms’ and ‘we trust in the church message’. Although all informants knew and heard church messages against premarital sex, many of them were sexually active. The perception was that young men were engaged in sexual activities with multiple partners as a result of sexual motivations surrounding masculinity and sexual potency, while young women sought multiple partners through transactional and intergenerational sex for economic reasons. These sexual practices of young people conflicted with church messages on sexual abstinence and faithfulness. However, a small number of participants challenged current gender norms and suggested alternative ways of being a man or a woman. To elucidate these  alternatives, we suggest that church youths and church leaders might take concrete actions to deconstruct misconceptions about being men. In this way, they can possibly enhance a frank and fruitful dialogue on sex, sexuality and gender to promote positive masculinities and constructive partnerships to prevent HIV.Keywords: masculinity, sexuality, young churchgoers, HIV prevention, gender equality, DR CongoDans le contexte actuel des e´glises Congolaises, les e´tudes relatives a` la masculinite´ sont presque re´centes et les jeunes chre´tiens constituent un groupe d’individus qui ne font pas l’objet des recherches scientifiques  approfondies. En re´ponse a` cette insuffisance de connaissances dans le contexte a` VIH, le pre´sent article tente d’explorer les discours relatifs a` la masculinite´ et a` la sexualite´ des jeunes chre´tiens issus des  quartiers de´favorise´s de Kinshasa. Une se´rie de 16 interviews semi-structure´es ont e´te´ mene´s aupre`s des jeunes chre´tiens ce´libataires appartenant a` l’Arme´e du Salut, aux e´glises Protestantes et a` celles du Re´veil du Congo. Les interviews ont e´te´ enregistre´es et analyse´es en utilisant la me´thode du discours. Cinq discours ont e´merge´ notamment: « Nous connaissons le message des e´glises au sujet du sexe », « les garc¸ons ont besoin des rapports sexuels », « les filles ont besoin d’argent », « faudrait-il utiliser ou ne pas utiliser les condoms » et « nous croyons dans le message des e´glises ». Alors que tous les participants  connaissaient le message des e´glises qui interdisent les rapports sexuels pre´maritaux, beaucoup d’entre eux e´taient de´ja` sexuellement actifs. Les garc¸ons ont e´te´ perc¸us comme des personnes qui ont des rapports sexuels avec plusieurs partenaires concomitants pour prouver leur masculinite´ et leur puissance sexuelle. Les filles chercheraient a` avoir des rapports sexuels mercantiles et interge´ne´rationnels avec des partenaires  multiples a` des fins e´conomiques. Ces pratiques sexuelles des jeunes s’opposent aux discours des e´glises  qui promeuvent l’abstinence sexuelle et la fide´lite´. Cependant, quelques participants ont remis en cause les normes courantes du genre et ont sugge´re´ des alternatives en ce qui concerne l’identite´ des hommes et des femmes. Pour les e´lucider, nous proposons que les jeunes chre´tiens et les leaders des e´glises puissent mener des actions concre`tes dans le but de de´construire les conceptions errone´es de ce que veut dire eˆtre homme. Ce faisant, ils peuvent probablement maximiser les chances d’un dialogue franc et productif en ce qui concerne le sexe, la sexualite´ et le genre afin de promouvoir la masculinite´ positive et le partenariat  constructif, susceptibles de pre´venir l’infection a` VIH.Mots cle´s: masculinite´, sexualite´, jeunes chre´tiens, pre´vention du VIH, e´galite´ du genre, RD Cong

Nursing assistants matters—An ethnographic study of knowledge sharing in interprofessional practice

© 2017 John Wiley & Sons Ltd Interprofessional collaboration involves some kind of knowledge sharing, which is essential and will be important in the future in regard to the opportunities and challenges in practices for delivering safe and effective health care. Nursing assistants are seldom mentioned as a group of health care workers that contribute to interprofessional collaboration in health care practice. The aim of this ethnographic study was to explore how the nursing assistants’ knowledge can be shared in a team on a spinal cord injury rehabilitation ward. Using a sociomaterial perspective on practice, we captured different aspects of interprofessional collaboration in health care. The findings reveal how knowledge was shared between professionals, depending on different kinds of practice architecture. These specific cultural–discursive, material–economic, and social–political arrangements enabled possibilities through which nursing assistants’ knowledge informed other practices, and others’ knowledge informed the practice of nursing assistants. By studying what health care professionals actually do and say in practice, we found that the nursing assistants could make a valuable contribution of knowledge to the team

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

Picturing protest: visuality, visibility and the public sphere (special issue introduction).

Aims and Scope: This special issue is concerned with how and why certain visual images picturing protest events and social movements are rendered visible or invisible in the public sphere. ‘Picturing Protest’ responds to the growing interest in a new protest culture and new ways of ‘doing politics’, ranging from Arab revolts to the Occupy Movement, the Indignados and anti-austerity protests in Europe. Since 2011 these new activisms have gained momentum in media and scholarly debates. Contemporary activisms are seen as powerfully tied in to the possibilities that social media platforms and web 2.0 technologies offer to those involved in practices of dissent in physical squares and streets as much as in virtual environments. Of special interest here is how new forms of political participation and the practice of dissent go in tandem with the widespread use of visual images and internet memes facilitated by technological devices with documentation facilities (e.g., smartphones, tablets) and social network technologies (Bennett and Segerberg 2012). Iconic images like the image of dying Neda, a 26-year-old Iranian woman killed by a sniper bullet during a protest event, go viral in social media platforms and have the power to galvanize the attention of global publics. Hence, this new protest culture demands for a different approach in the study of how protest images are constituted, analysed, interpreted and circulated in both old and new media environments. Taken all together, the different contributions ask how and why activists, photojournalists, citizen journalists and journalists use protest images, ranging from maps, posters, to amateur and professional photographs, to communicate with a range of audiences within and beyond nationally-defined public spheres. The contributors do so by employing theoretical tools and methods that originate from within a variety of disciplines, including media and communication, political science, sociology, semiotics and art history. In pursuing their research, the contributors draw on a variety of political contexts, including Spain, Portugal, the West Bank and the Gaza Strip, Greece, Germany, Italy, Austria and the UK. One of the key aims of this special issue is to overcome the overemphasis on the intended symbolic meanings of protest images (Philipps, 2011), by directing the analytical lens to issues of image production and diffusion. It does so to show how certain visual images, and not others, end up circulating in a range of traditional and new media environments