Green's functions for far-side seismic images: a polar expansion approach

We have computed seismic images of magnetic activity on the far surface of the Sun by using a seismic-holography technique. As in previous works, the method is based on the comparison of waves going in and out of a particular point in the Sun but we have computed here the Green's functions from a spherical polar expansion of the adiabatic wave equations in the Cowling approximation instead of using the ray-path approximation previously used in the far-side holography. A comparison between the results obtained using the ray theory and the spherical polar expansion is shown. We use the gravito-acoustic wave equation in the local plane-parallel limit in both cases and for the latter we take the asymptotic approximation for the radial dependencies of the Green's function. As a result, improved images of the far-side can be obtained from the polar-expansion approximation, especially when combining the Green's functions corresponding to two and three skips. We also show that the phase corrections in the Green's functions due to the incorrect modeling of the uppermost layers of the Sun can be estimated from the eigenfrequencies of the normal modes of oscillation.Comment: 8 pages, 5 figures, Astrophysical Journal, accepted (2010

Community Collaboration in Development Work with Young People: Perspectives from Zambian Communities

Despite its recognised importance, studies of collaboration within specific communities in the Global South are rare. This paper examines the purposes and processes of collaboration between organisations undertaking development work with young people in two communities in Lusaka, Zambia. Interviewees recognised the need for collaboration given the limitations of existing provision and the fragmented organisational context. Existing collaboration was commonly orientated towards information sharing and joint provision rather than broader coordinated planning. Building awareness and understanding across organisations were viewed as key processes in developing collaboration. To enhance collaboration between organisations, it is suggested that inclusive community forums be instigated

Distinctive policy diffusion patterns, processes and actors: Drawing implications from the case of sport in international development

This article examines the diffusion of “Sport for Development and Peace” (SDP) across sub-Saharan Africa following global policy impetus provided by international organizations, including the United Nations, since the start of the twenty-first century. In so doing, the article centres on a geographical region that has been unconsidered in the policy diffusion literature and, particularly, responds to calls for research into the effects of policy characteristics on diffusion mechanisms and patterns. This rationale beget methods that differed from the predominant use of quantitative, dichotomous indicators of policy diffusion, instead integrating data from global, international and national policy documents, from a review of SDP literature, and from stakeholder interviews in Ghana and Tanzania. Patterns of increasing governmental engagement with, but limited implementation of, SDP policies contrasted with the significant expansion of SDP provision by diverse NGOs. In turn, these patterns represented the varying influence of different diffusion mechanisms on state and non-state actors. Compared with the diffusion of other types of policies, these findings indicated the effects of an instrumental, malleable but complex global policy model for SDP diffusion. There is, therefore, significant value in further research that examines how policy diffusion may depend on the configuration of particular policy characteristics, mechanisms and actors

Sport for development and transformative social change: The potential of Margaret Archer’s Morphogenetic Approach to reconceptualise a longstanding problem

Frequent calls for sport-for-development (SfD) to be re-oriented towards transformative social change reflect the extent that policies and programmes have instead focused on individualised forms of personal development. However, SfD research has yet to substantially address fundamental ontological assumptions and underlying conceptualisations of transformative social change. To addresses this gap, we consider how Margaret Archer’s Morphogenetic Approach can help explain how transformative social change might occur through SfD activities. Three conceptual contributions are brought into focus: (1) assuming a realist social ontology, (2) making distinctions between structure, culture and agency, and (3) identifying social change as happening across three temporal phases. We conclude by identifying potential benefits and implications of applying the Morphogenetic Approach to consider the potential for SfD to contribute to social change

Anthropogenic Habitats Facilitate Dispersal of an Early Successional Obligate: Implications for Restoration of an Endangered Ecosystem

Landscape modification and habitat fragmentation disrupt the connectivity of natural landscapes, with major consequences for biodiversity. Species that require patchily distributed habitats, such as those that specialize on early successional ecosystems, must disperse through a landscape matrix with unsuitable habitat types. We evaluated landscape effects on dispersal of an early successional obligate, the New England cottontail (Sylvilagus transitionalis). Using a landscape genetics approach, we identified barriers and facilitators of gene flow and connectivity corridors for a population of cottontails in the northeastern United States. We modeled dispersal in relation to landscape structure and composition and tested hypotheses about the influence of habitat fragmentation on gene flow. Anthropogenic and natural shrubland habitats facilitated gene flow, while the remainder of the matrix, particularly development and forest, impeded gene flow. The relative influence of matrix habitats differed between study areas in relation to a fragmentation gradient. Barrier features had higher explanatory power in the more fragmented site, while facilitating features were important in the less fragmented site. Landscape models that included a simultaneous barrier and facilitating effect of roads had higher explanatory power than models that considered either effect separately, supporting the hypothesis that roads act as both barriers and facilitators at all spatial scales. The inclusion of LiDAR-identified shrubland habitat improved the fit of our facilitator models. Corridor analyses using circuit and least cost path approaches revealed the importance of anthropogenic, linear features for restoring connectivity between the study areas. In fragmented landscapes, human-modified habitats may enhance functional connectivity by providing suitable dispersal conduits for early successional specialists

Learning How to Influence Others: A Training Module and Experiential Exercise

Effective leaders in the 21st century must be able to elicit desired changes through one-on-one dialogues, in small groups, and through speeches as well as other communication channels directed at broader audiences. Unfortunately, knowledge about influence tactics does not necessarily translate into effective usage. Therefore, we developed a training module and experiential exercise that provide participants, as influence agents, practice using 11 proactive influence tactics. The module also provides participants, as targets, practice in identifying uses of the tactics in various real-life situations. The authors developed training materials and instructions to help participants gain a deeper understanding of the influence process. Materials provided for instructors include an interactive student handout, a two-part homework assignment including a solutions key, a list of sample scenarios, and a list of tactics to be used in the exercise

Chemical probes for methyl lysine reader domains

The primary intent of a chemical probe is to establish the relationship between a molecular target, usually a protein whose function is modulated by the probe, and the biological consequences of that modulation. In order to fulfill this purpose, a chemical probe must be profiled for selectivity, mechanism of action, and cellular activity, as the cell is the minimal system in which ‘biology’ can be explored. This review provides a brief overview of progress toward chemical probes for methyl lysine reader domains with a focus on recent progress targeting chromodomains

Submillimeter observations of solar limb-brightening in the total solar eclipse of 31 July 1981

Eight flights of the Kuiper Airborne Observatory (KAO) were devoted to solar observation. The successful observation of a total solar eclipse was accomplished. The observations were made simultaneously at 30, 50, 100, and 200 microns. The successful adaptation of the KAO for solar observations thus provided the most detailed data to date in this spectral band. The results from a preliminary analysis of the KAO data are summarized: (1) the 200 micron limb is extended about 3 arc sec above the 30 micron limb, indicating the prescence of cool dense material up to the altitudes of spicules; (2) strong radial darkening of the quiet sun intensity profile appeared at 200 microns, probably an indication that hot material in the low chromosphere is recessed into vertical magnetic flux tubes embedded in a cooler nonmagnetic substrate, which obscures the heated material approaching the limb; (3) active regions were observed to undergo a strong increase in contrast above the quiet sun background at wave lengths of 100 microns and longer; and (4) the moon was mapped for use as a photometric standard for determining the absolute intensity of the sun in all four wavelength bands