Ageing of Natural Rubber under Stress

We report a dynamical-mechanical study of stress relaxation at small deformation in a natural (polyisoprene) rubber well above its glass transition temperature Tg. We find that an almost complete relaxation of stress takes place over very long periods of time, even though the elastic network integrity is fully retained. The relaxation rate and the long-time equilibrium modulus are sensitive functions of temperature which do not follow time-temperature superposition. Many characteristic features of non-ergodic ageing response are apparent at both short and very long times. We interpret the observed behaviour in terms of the properties of rubber crosslinks, capable of isomerisation under stress, and relate the results to recent models of soft glassy rheology.Comment: Latex 2e (EPJ style), 5 EPS figure

Static potential in scalar QED3_3 with non-minimal coupling

Here we compute the static potential in scalar $QED_3$ at leading order in $1/N_f$. We show that the addition of a non-minimal coupling of Pauli-type (\eps j^{\mu}\partial^{\nu}A^{\alpha}), although it breaks parity, it does not change the analytic structure of the photon propagator and consequently the static potential remains logarithmic (confining) at large distances. The non-minimal coupling modifies the potential, however, at small charge separations giving rise to a repulsive force of short range between opposite sign charges, which is relevant for the existence of bound states. This effect is in agreement with a previous calculation based on M$\ddot{o}$ller scattering, but differently from such calculation we show here that the repulsion appears independently of the presence of a tree level Chern-Simons term which rather affects the large distance behavior of the potential turning it into constant.Comment: 13 pages, 3 figure

Emotions, Violence and Social Belonging: an Eliasian Analysis of Sports Spectatorship

This paper examines the development of different forms of spectator violence in terms of the socio-temporal structure of situational dynamics at Gaelic football matches in Ireland. The nature of violent encounters has shifted from a collective form based on local solidarity and a reciprocal code of honour, through a transitional collective form based on deferred emotional satisfaction and group pride, towards increasing individualization of spectator violence. This occurs due to the shifting objects of emotional involvement. As the functional specialization of the various roles in the game is partially accepted by spectators, the referee becomes the target of anger. Violence becomes more individualized as ‘mutually expected self-restraint’ proceeds within the context of relative state pacification beyond the field of play and the formation of a less volatile habitus. We use Elias’s figurational perspective on violence over the micro-interactional approach of Randall Collins, but support Collins’ emphasis on state legitimacy

The supernova impostor PSN J09132750+7627410 and its progenitor

We report the results of our follow-up campaign of the supernova impostor PSN J09132750+7627410, based on optical data covering $\sim250\,\rm{d}$. From the beginning, the transient shows prominent narrow Balmer lines with P-Cygni profiles, with a blue-shifted absorption component becoming more prominent with time. Along the $\sim3\,\rm{months}$ of the spectroscopic monitoring, broad components are never detected in the hydrogen lines, suggesting that these features are produced in slowly expanding material. The transient reaches an absolute magnitude $M_r=-13.60\pm0.19\,\rm{mag}$ at maximum, a typical luminosity for supernova impostors. Amateur astronomers provided $\sim4\,\rm{years}$ of archival observations of the host galaxy, NGC 2748. The detection of the quiescent progenitor star in archival images obtained with the Hubble Space Telescope suggests it to be an $18-20$\msun white-yellow supergiant.Comment: 7 pages, 4 figures, supplemental material available in the source file. Accepted for publication on Astrophysical Journal Letter

Genetic diversity of peanut (Arachis hypogaea L.) and its wild relatives based on the analysis of hypervariable regions of the genome

BACKGROUND: The genus Arachis is native to a region that includes Central Brazil and neighboring countries. Little is known about the genetic variability of the Brazilian cultivated peanut (Arachis hypogaea, genome AABB) germplasm collection at the DNA level. The understanding of the genetic diversity of cultivated and wild species of peanut (Arachis spp.) is essential to develop strategies of collection, conservation and use of the germplasm in variety development. The identity of the ancestor progenitor species of cultivated peanut has also been of great interest. Several species have been suggested as putative AA and BB genome donors to allotetraploid A. hypogaea. Microsatellite or SSR (Simple Sequence Repeat) markers are co-dominant, multiallelic, and highly polymorphic genetic markers, appropriate for genetic diversity studies. Microsatellite markers may also, to some extent, support phylogenetic inferences. Here we report the use of a set of microsatellite markers, including newly developed ones, for phylogenetic inferences and the analysis of genetic variation of accessions of A. hypogea and its wild relatives. RESULTS: A total of 67 new microsatellite markers (mainly TTG motif) were developed for Arachis. Only three of these markers, however, were polymorphic in cultivated peanut. These three new markers plus five other markers characterized previously were evaluated for number of alleles per locus and gene diversity using 60 accessions of A. hypogaea. Genetic relationships among these 60 accessions and a sample of 36 wild accessions representative of section Arachis were estimated using allelic variation observed in a selected set of 12 SSR markers. Results showed that the Brazilian peanut germplasm collection has considerable levels of genetic diversity detected by SSR markers. Similarity groups for A. hypogaea accessions were established, which is a useful criteria for selecting parental plants for crop improvement. Microsatellite marker transferability was up to 76% for species of the section Arachis, but only 45% for species from the other eight Arachis sections tested. A new marker (Ah-041) presented a 100% transferability and could be used to classify the peanut accessions in AA and non-AA genome carriers. CONCLUSION: The level of polymorphism observed among accessions of A. hypogaea analyzed with newly developed microsatellite markers was low, corroborating the accumulated data which show that cultivated peanut presents a relatively reduced variation at the DNA level. A selected panel of SSR markers allowed the classification of A. hypogaea accessions into two major groups. The identification of similarity groups will be useful for the selection of parental plants to be used in breeding programs. Marker transferability is relatively high between accessions of section Arachis. The possibility of using microsatellite markers developed for one species in genetic evaluation of other species greatly reduces the cost of the analysis, since the development of microsatellite markers is still expensive and time consuming. The SSR markers developed in this study could be very useful for genetic analysis of wild species of Arachis, including comparative genome mapping, population genetic structure and phylogenetic inferences among species

Implementasi Kebijakan Corporate Social Responsibility pada PT. Trimegah Bangun Persada di Desa Kawasi Kecamatan Obi Kabupaten Halmahera Selatan

PT. Trimegah Bangun Persada is located in the village Kawasi District of Obi South Halmahera Regency is a nickel mining company is also in addition to seeking profits are also trying to implement corporate social responsibiliti so that in addition to increasing the sompany's image better in view Stakehoulders also increase the company's role in improving the welfare and social responsibility enviromental the people around and the people in North Maluku,as it has been in good mandated in Law No.4 of 2009 on mining minerals,article 1 paragraph 3 of Law No.40 of 2007 a limited liability company. The purpose of this study was to analyze the policy implementation of Corporate Social Responsibility PT. Trimegah Bangun Persada in the Village Kawasi Obi District of South Halmahera Regency. The research found that the application of CSR implementation is based on the Memorandum of Agreement between the management of PT. Trimegah Bangun Persada South Halmahera District Government and Rural Society Kawasi which resulted in a 9-point agreement has been implemented as a CSR program. Models or patterns of CSR adopted by the company in the form of direct involvement. The motive for companies to implement CSR is a profit motive, the community, and the environment. CSR implementation benefits include: improving public welfare, environmental protection, community development, rural development as well as the nation

Personal goals, group performance and ‘social’ networks: participants’ negotiation of virtual and embodied relationships in the ‘Workplace Challenge’ physical activity programme

County Sports Partnerships (CSPs) epitomise the growing reliance upon building networks and partnerships sports delivery. This study investigated how social networks were created and contested in a CSP-led programme entitled the ‘Workplace Challenge’ (WPC). The WPC used a web-platform to encourage workplace-based teams to engage in physical activity by self-recording their activity over an eight-week period. Points were awarded for activity completed and a peer-challenge facility was promoted via online league tables, prizes and the opportunity to ‘challenge’ other users. Semi-structured interviews were conducted with a total of seventeen participants recruited from one public and one private sector workplace and from a sample of participants registered as individuals. Two programme planners employed by the CSP also took part. A figurational framework was utilised to investigate participants’ negotiation of networks of embodied and virtual relationships within the programme. Findings suggest the messages promoted in the WPC were disseminated and transformed according to the organizational structure of these networks. Embodied social relationships within workplaces reinforced peer support in professional I-we identities, whereas virtual networks sometimes highlighted participants’ isolation. Moreover, emphasis upon competition within and between teams caused some to question their performance. Often, competition motivated engagement. For less active participants, constant comparison could prove discouraging, particularly if participants felt they had let their colleagues down. Planners of similar programmes must be cognizant of the uneven manner of programme dissemination. Contextual differences at the point of delivery including existing organizational structures and power hierarchies have an impact upon participants’ perceptions of a programme

SN 2013df, a double-peaked IIb supernova from a compact progenitor and an extended H envelope

Optical observations of the type IIb SN 2013df from a few days to about 250 days after explosion are presented. These observations are complemented with UV photometry taken by \textit{SWIFT} up to 60 days post-explosion. The double-peak optical light curve is similar to those of SNe 1993J and 2011fu although with different decline and rise rates. From the modelling of the bolometric light curve, we have estimated that the total mass of synthesised $^{56}$Ni in the explosion is $\sim0.1$ M$_{\odot}$, while the ejecta mass is $0.8-1.4$ M$_{\odot}$ and the explosion energy $0.4-1.2 \times 10^{51}$erg. In addition, we have estimated a lower limit to the progenitor radius ranging from $64-169$ $R_{\odot}$. The spectral evolution indicates that SN 2013df had a hydrogen envelope similar to SN 1993J ($\sim 0.2$ M$_{\odot}$). The line profiles in nebular spectra suggest that the explosion was asymmetric with the presence of clumps in the ejecta, while the [O\,{\sc i}] $\lambda$$\lambda$$6300$, $6364$ luminosities, may indicate that the progenitor of SN 2013df was a relatively low mass star ( $\sim 12-13$ M$_{\odot}$).Comment: 18 pages, 11 figures, 9 tables, accepted for publication in MNRA

On the origin of the neutral hydrogen supershells: the ionized progenitors and the limitations of the multiple supernovae hypothesis

Here we address the question whether the ionized shells associated with giant HII regions can be progenitors of the larger HI shell-like objects found in the Milky Way and other spiral and dwarf irregular galaxies. We use for our analysis a sample of 12 HII shells presented recently by Rela\~no et al. (2005, 2007). We calculate the evolutionary tracks that these shells would have if their expansion is driven by multiple supernovae explosions from the parental stellar clusters. We find, contrary to Rela\~no et al. (2007), that the evolutionary tracks of their sample HII shells are inconsistent with the observed parameters of the largest and most massive neutral hydrogen supershells. We conclude that HII shells found inside giant HII regions may represent the progenitors of small or intermediate HI shells, however they cannot evolve into the largest HI objects unless, aside from the multiple supernovae explosions, an additional energy source contributes to their expansion.Comment: Accepted for publication in ApJ, tentatively scheduled for the ApJ July 1, 2008, v681n1 issue. 19 pages, 4 figure