On the modulation instability development in optical fiber systems

Extensive numerical simulations were performed to investigate all stages of modulation instability development from the initial pulse of pico-second duration in photonic crystal fiber: quasi-solitons and dispersive waves formation, their interaction stage and the further propagation. Comparison between 4 different NLS-like systems was made: the classical NLS equation, NLS system plus higher dispersion terms, NLS plus higher dispersion and self-steepening and also fully generalized NLS equation with Raman scattering taken into account. For the latter case a mechanism of energy transfer from smaller quasi-solitons to the bigger ones is proposed to explain the dramatical increase of rogue waves appearance frequency in comparison to the systems when the Raman scattering is not taken into account.Comment: 9 pages, 54 figure

Independent expert advisory bodies facilitate ambitious climate policy responses

Evidence suggests that independent expert advisory bodies are emerging as strong assets that can help governments raise ambition and deliver climate objectives in practice

Advising national climate policy makers: A longitudinal analysis of the UK Climate Change Committee

Despite the recent proliferation of national climate change advisory bodies, very little is known about what advice they provide, to whom, and when. To address these gaps in the literature, this article systematically analyses all 700 of the recommendations made by the UK Climate Change Committee (CCC) in the period 2009–20. The CCC is one of the oldest climate change advisory bodies of its kind in the world and its design has been widely emulated by other countries. For the first time, this article documents how the CCC’s mitigation and adaptation recommendations have changed over time with respect to their addressee, sectoral focus and policy targets. It reveals that they became: more numerous per year; more cross-sectoral in their nature; clearer in targeting a specific addressee; and more focused in referring to specific policy targets. By drawing on Fischer’s synthesis of policy evaluation to derive a measure of policy ambition, it also reveals that despite many of its recommendations being repeated year after year, the CCC has become more willing to challenge the policy status quo. It concludes by identifying future research needs in this important and fast-moving area of climate governance, notably understanding the conditions in which the recommendations of advisory bodies (do not) impact national policy

Mapping the Philippines’ Mangrove Forests Using Landsat Imagery

Current, accurate, and reliable information on the areal extent and spatial distribution of mangrove forests in the Philippines is limited. Previous estimates of mangrove extent do not illustrate the spatial distribution for the entire country. This study, part of a global assessment of mangrove dynamics, mapped the spatial distribution and areal extent of the Philippines’ mangroves circa 2000. We used publicly available Landsat data acquired primarily from the Global Land Survey to map the total extent and spatial distribution. ISODATA clustering, an unsupervised classification technique, was applied to 61 Landsat images. Statistical analysis indicates the total area of mangrove forest cover was approximately 256,185 hectares circa 2000 with overall classification accuracy of 96.6% and a kappa coefficient of 0.926. These results differ substantially from most recent estimates of mangrove area in the Philippines. The results of this study may assist the decision making processes for rehabilitation and conservation efforts that are currently needed to protect and restore the Philippines’ degraded mangrove forests

The changing patterns of group politics in Britain

Two interpretations of ways in which group politics in Britain have presented challenges to democracy are reviewed: neo-corporatism or pluralistic stagnation and the rise of single issue interest groups. The disappearance of the first paradigm created a political space for the second to emerge. A three-phase model of group activity is developed: a phase centred around production interests, followed by the development of broadly based 'other regarding' groups, succeeded by fragmented, inner directed groups focusing on particular interests. Explanations of the decay of corporatism are reviewed. Single issue group activity has increased as party membership has declined and is facilitated by changes in traditional media and the development of the internet. Such groups can overload the policy-making process and frustrate depoliticisation. Debates about the constitution and governance have largely ignored these issues and there is need for a debate

Mapping Primary Gyrogenesis During Fetal Development in Primate Brains: High-Resolution in Utero Structural MRI of Fetal Brain Development in Pregnant Baboons

The global and regional changes in the fetal cerebral cortex in primates were mapped during primary gyrification (PG; weeks 17–25 of 26 weeks total gestation). Studying pregnant baboons using high-resolution MRI in utero, measurements included cerebral volume, cortical surface area, gyrification index and length and depth of 10 primary cortical sulci. Seven normally developing fetuses were imaged in two animals longitudinally and sequentially. We compared these results to those on PG that from the ferret studies and analyzed them in the context of our recent studies of phylogenetics of cerebral gyrification. We observed that in both primates and non-primates, the cerebrum undergoes a very rapid transformation into the gyrencephalic state, subsequently accompanied by an accelerated growth in brain volume and cortical surface area. However, PG trends in baboons exhibited some critical differences from those observed in ferrets. For example, in baboons, the growth along the long (length) axis of cortical sulci was unrelated to the growth along the short (depth) axis and far outpaced it. Additionally, the correlation between the rate of growth along the short sulcal axis and heritability of sulcal depth was negative and approached significance (r = −0.60; p < 0.10), while the same trend for long axis was positive and not significant (p = 0.3; p = 0.40). These findings, in an animal that shares a highly orchestrated pattern of PG with humans, suggest that ontogenic processes that influence changes in sulcal length and depth are diverse and possibly driven by different factors in primates than in non-primates

Growth and wood properties of genetically improved loblolly pine: propagation type comparison and genetic parameters

The use of clonal varieties in forestry offers great potential to improve growth traits (quantity) and wood properties (quality) of loblolly pine (Pinus taeda L.). Loblolly pine trees established via somatic embryogenesis (clones), full-sib zygotic crosses, and half-sib zygotic open-pollinated families were sampled to identify variation in growth and wood properties among and within clonal lines and zygotic controls. Increment cores 5 mm in diameter were collected at age 4 from a total of 2615 trees. Growth properties (diameter at 1.4 m and total tree height) and wood properties (whole-core density, latewood and earlywood density, and latewood percent) were measured for each tree sampled in the study. Overall, growth properties were better for full-sib seedling than for clonal lines, whereas wood density was higher for clonal lines than full-sib and open-pollinated seedlings. However, there were clonal lines with better growth and higher wood density. Clonal repeatability of both growth and wood properties across sampled sites and genetic correlations between growth and wood traits were determined, with higher repeatability observed for wood traits compared with growth traits. Significant genetic correlations were observed for tree height and wood properties, whereas weak correlations were observed for diameter and wood properties