Fire & Global Change During Key Intervals of the Late Triassic & Early Jurassic with a Focus on the Central Polish Basin

Core from modern-day Poland recovering fluvial and paralic strata provides an excellent record of climatic and environmental changes in the Central Polish Basin during two key intervals of the Early Jurassic. Thick successions of Rhaetian-Hettangian and Pliensbachian-Toarcian age are examined using a number of techniques in order to understand the wildfire activity history, carbon-cycle interactions, and organic matter composition of sediments at two sites in the Central Polish Basin. Physical and geochemical proxies for wildfire activity show evidence of increased wildfire activity both prior to and after the Toarcian Oceanic Anoxic Event (OAE) at the Kazewy-1 site, with suppression of wildfire activity during the negative carbon-isotope excursion of the OAE. Correlation with published wildfire activity proxy records from additional sites in the Tethyan realm shows that this pattern was not limited to the Central Polish Basin, but is part of a wider, regional change. Additionally, new wildfire activity proxy records show increased wildfire activity across the Triassic-Jurassic Boundary at the Kaszewy-1 and Niekłań PIG-1 sites in the Central Polish Basin, correlating with other contemporaneous proxy records from Denmark and Greenland. New carbon-isotope records generated from terrestrial organic matter from the Niekłań PIG-1 core show trends towards heavier δ¹³C values immediately after the Triassic-Jurassic Boundary, providing evidence of a perturbation to the carbon-cycle at this time. Exploratory investigation of sediments from the Kaszewy-1 core provides a new record of BIT indices of Early Jurassic sediments, surpassing the oldest-known use of this terrestrial organic matter input proxy. Additionally, a newly-developed technique is used to investigate carbon-isotope variability in fossil terrestrial organic matter across the Toarcian Oceanic Anoxic Event carbon-isotope excursions. A new record of individual phytoclast δ¹³C values demonstrates that, despite δ¹³C variability between phytoclasts from a single horizon, larger overall trends in δ¹³C values can be identified from single phytoclast δ¹³C measurements.Core from modern-day Poland recovering fluvial and paralic strata provides an excellent record of climatic and environmental changes in the Central Polish Basin during two key intervals of the Early Jurassic. Thick successions of Rhaetian-Hettangian and Pliensbachian-Toarcian age are examined using a number of techniques in order to understand the wildfire activity history, carbon-cycle interactions, and organic matter composition of sediments at two sites in the Central Polish Basin. Physical and geochemical proxies for wildfire activity show evidence of increased wildfire activity both prior to and after the Toarcian Oceanic Anoxic Event (OAE) at the Kazewy-1 site, with suppression of wildfire activity during the negative carbon-isotope excursion of the OAE. Correlation with published wildfire activity proxy records from additional sites in the Tethyan realm shows that this pattern was not limited to the Central Polish Basin, but is part of a wider, regional change. Additionally, new wildfire activity proxy records show increased wildfire activity across the Triassic-Jurassic Boundary at the Kaszewy-1 and Niekłań PIG-1 sites in the Central Polish Basin, correlating with other contemporaneous proxy records from Denmark and Greenland. New carbon-isotope records generated from terrestrial organic matter from the Niekłań PIG-1 core show trends towards heavier δ¹³C values immediately after the Triassic-Jurassic Boundary, providing evidence of a perturbation to the carbon-cycle at this time. Exploratory investigation of sediments from the Kaszewy-1 core provides a new record of BIT indices of Early Jurassic sediments, surpassing the oldest-known use of this terrestrial organic matter input proxy. Additionally, a newly-developed technique is used to investigate carbon-isotope variability in fossil terrestrial organic matter across the Toarcian Oceanic Anoxic Event carbon-isotope excursions. A new record of individual phytoclast δ¹³C values demonstrates that, despite δ¹³C variability between phytoclasts from a single horizon, larger overall trends in δ¹³C values can be identified from single phytoclast δ¹³C measurements

Molecular ions in L1544. I. Kinematics

We have mapped the dense dark core L1544 in H13CO+(1-0), DCO+(2-1), DCO+(3-2), N2H+(1-0), NTH+(3-2), N2D+(2-1), N2D+(3-2), C18O(1-0), and C17O(1-0) using the IRAM 30-m telescope. We have obtained supplementary observations of HC18O+(1-0), HC17O+(1-0), and D13CO+(2-1). Many of the observed maps show a general correlation with the distribution of dust continuum emission in contrast to C18O(1-0) and C17O(1-0) which give clear evidence for depletion of CO at positions close to the continuum peak. In particular N2D+(2-1) and (3-2) and to a lesser extent N2H+(1-0) appear to be excellent tracers of the dust continuum. We find that the tracers of high density gas (in particular N2D+) show a velocity gradient along the minor axis of the L1544 core and that there is evidence for larger linewidths close to the dust emission peak. We interpret this using the model of the L1544 proposed by Ciolek & Basu (2000) and by comparing the observed velocities with those expected on the basis of their model. The results show reasonable agreement between observations and model in that the velocity gradient along the minor axis and the line broadening toward the center of L1544 are predicted by the model. This is evidence in favour of the idea that amipolar diffusion across field lines is one of the basic processes leading to gravitational collapse. However, line widths are significantly narrower than observed and are better reproduced by the Myers & Zweibel (2001) model which considers the quasistatic vertical contraction of a layer due to dissipation of its Alfvenic turbulence, indicating the importance of this process for cores in the verge of forming a star.Comment: 24 pages, 9 figures, to be published in Ap

Questioning the media-democracy link: South African’s journalists’ views

ABSTRACT It is often assumed that a robust, free and independent media will contribute to the deepening of democracy by keeping governments accountable and broadening citizen participation in deliberative democratic debates. But in new democracies such as South Africa, the deepening and broadening of democratic participation is often curtailed by challenges such as unequal access to the media, the orientation of mainstream media towards elite audiences and renewed attempts by sources of power to control the free flow of information. Despite the promise of a peaceful, equitable and democratic society after the end of apartheid, conflicts continue to erupt due to continued social polarisation, vast socio-economic inequalities and new struggles for power. In South Africa these conflicts include social protests on a daily basis, repeated outbreaks of xenophobic violence and disruptions to the parliamentary process. This paper probes the role of the media in these conflicts from the perspective of journalists who have reported on these issues. The paper explores ways in which journalists critically reflect on their abilities to perform the roles expected of them within a normative framework informed by the Habermasian ideal of deliberative democracy. The reasons they offer for not fulfilling these roles, and the conditions underpinning these failures, lead them to question the ability of the South African media to contribute to an emerging democracy

Just noticeable gamma differences and acceptability of sRGB images displayed on a CRT monitor

The standard RGB colour space (sRGB) has been proposed as a means for obtaining accurate reproduction of colour and tone for images displayed across the Internet, provided that they are viewed under the reference display and viewing conditions defined in the standard. It has been found, however, that typical display and viewing conditions when accessing online images vary and therefore deviate from the reference sRGB conditions. One of the parameters that may affect the perceived quality of online images is the gamma setting of the display. In this work psychophysical experiments were conducted to determine the imperceptibility and acceptability of gamma differences of sRGB images when they are viewed on cathode ray tube displays. These experiments were carried out under both controlled and uncontrolled display and viewing conditions. The results of these experiments are presented and discussed, including the estimated points of subjective equality and the just noticeable difference of gamma values

Inventory of novel approaches to seed quality assurance mechanisms for vegetatively propagated crops (VPCs) in seven African countries

This paper provides an inventory of novel approaches to and mechanisms for quality assurance of the seeds of vegetatively produced crops (VPCs). It explores to what extent seven African countries (Ethiopia, Kenya, Malawi, Nigeria, Tanzania, Uganda and Zambia) are decentralising and integrating VPC seed systems, in terms of regulations governing the sector, methods of seed production, and methods of seed inspection and certification. It consolidates existing data and presents new data on decentralised seed quality assurance (SQA) approaches for VPCs in these seven selected countries. It makes relevant information readily available for policy dialogue on appropriate and inclusive SQA approaches, by providing an assessment of (i) the extent to which SQA has been decentralised, i.e., the extent to which third-party accredited inspectors have been deployed; (ii) countries’ use of e-certification platforms; (iii) the involvement of seed producer groups and cooperatives in SQA; and (iv) any novel approaches to disease diagnostics or other relevant aspects of SQA. The paper uses different, appropriately sequenced methods to ensure the different methods complement each other to offset the disadvantages of each method. These include a comprehensive literature review, an online survey, and key informants’ virtual interviews. These are complemented by expert interviews, especially with both IITA and CIP experts based in Tanzania, Uganda, and Ethiopia plus one CIP expert with overall knowledge of the project countries in Africa. Based on an online survey completed by officials from regulatory agencies from eight countries, and follow-up interviews with seed certification officials and researchers in the seed sector, the paper finds that almost all studied countries have some sort of decentralised seed production system in place, allowing large-scale companies, medium-semi-commercial companies and small holder farmers opportunities to produce both quality declared and certified seeds. These decentralised seed production systems may be regarded as novel, in that they deviate from the standard seed system practices proposed at international level, which focus on enforcing certified seed production. Further, the novelty is based on different countries adopting different processes because of different local constraints and different government/political structures. Such novelty is necessary in the African context of, inter alia, poor infrastructure for transporting VPC seeds long distance and limited technical skills for certifying seed. The innovative approaches chosen by these African countries are suitable for VPC seeds like those of cassava, sweetpotato, bananas, yams and potato – all of which have bulky and perishable planting materials. The paper shows that it is possible to make decentralised VPC seed systems a reality in the right circumstances, and that in some cases countries have already made strides in doing so. However, several gaps exist in different countries, all of which need to be addressed. They include problems such as (i) legislation and regulations not specifically considering the quality assurance requirements of VPCs; (ii) shortages of trained staff throughout the system, but especially in far-flung areas; (iii) unavailable or inadequate training materials and handbooks; (iv) inadequate resources at local level, including support for inspection equipment and resources (e.g., vehicles); (v) poor monitoring and administration capacity in farmers’ cooperatives/associations; and (vi) poor consideration given to gender empowerment. Each of these and other issues are discussed throughout the report and in the recommendations at the end of the document. Stakeholders in the VPC sectors need to address key challenges facing VPC seed producers and users such as the lack of specific regulations for VPCs and standards, especially in the countries which are either still developing such standards and regulations, or entirely do not have such tools in place. The absence of crop specific guidelines and standard operating procedures result in (i) low capacity to produce quality VPC seed, (ii) poor storage and handling facilities for seed and (iii) inadequate experience, technical skills and training among the seed inspectors and certifying officials from state seed regulatory agencies, especially lack of staff specialised in certifying VPCs. Simple, flexible and less bureaucratic systems are much more desirable for developing countries, even while countries must maintain a focus on quality control and quality assurance mechanisms within the legal provisions of seed laws, including those of novel approaches (Loch and Boyce, 2001). Quality control and quality assurance are important preconditions for ensuring the availability of planting materials and for piloting novel approaches such as decentralised seed production and quality control approaches. It is thus important for countries to mainstream and scale up sustainable quality assurance systems that work by establishing context-appropriate seed regulatory frameworks. While individual farmers, farm-based associations, farmer cooperatives and private companies have invested and continue to invest in production of VPC seeds, public investments in this sector are needed to realise wider system change and impact. Because VPC seeds are bulky, perishable and have high disease risks, many seed companies are not interested in these crops. Therefore, is important to secure political buy-in for decentralised VPC production and devolved VPC seed inspection so that states are encouraged to invest in supporting regulatory agencies and decentralised offices to deliver their services efficiently and effectively. In turn, this will allow farmers to secure the extension services they require. To ensure scalability and sustainability of novel approaches like the decentralisation of seed production and quality assurance, piloted initiatives must be sustained, including (i) for capacity development; (ii) providing adequate resources (competent personnel, funding and the necessary technologies like electronic platforms); and (iii) more importantly, the presence of an entrenched policy, legal and institutional framework that is implemented on the ground. As part of the remedy for these challenges, the paper recommends that engaged stakeholders in the VPCs sector provide targeted training of seed inspectors. In many countries, seed standards for VPCs and provisions in the law were designed based on the experiences of grain (maize) seeds, which have significant differences with VPCs. Therefore, seed inspectors need training for inspection of VPCs (i.e. varietal identification, crop specific pests and diseases). This can be complemented by capacity development efforts at different levels; for example, (i) training extension officers to undertake inspections and how to use relevant equipment (including any ICT devices); (ii) training seed producer associations on technical and governance/administrative aspects for ensuring equity, accountability and monitoring; and (iii) training seed producers to inspect their own seed and fields. Countries need to establish and scale up seed producers’ associations. In countries where seed producer associations are in place, they have shown to be cost-effective by mobilising fellow seed producers who need seed inspections to pay inspectors as a group instead of as individuals. This has in turn also driven the demand for inspection from the relevant authorities, because inspection activities such as these generate income for government agencies. With associations in place, it is possible to help seed producers and farmers to identify markets for both seed and produce, to create a virtuous cycle whereby producers buy improved seed because they have a market for their improved produce. Finally, stakeholders need to implement or scale up e-certification platforms like SeedTrackerTM to reduce the burden and costs associated with manual and physical activities related to seed inspection and certification. Where ICT systems such as SeedTrackerTM have not been implemented, roll these out in all countries, ensuring both that they are suitable for each country’s specific needs, and that they align with regional and international seed policy. In countries like Nigeria and Tanzania where SeedTrackerTM is in place, it is imperative that most of these tools are improved to address the current limitations. Meanwhile, achievements – including the use of successful ICT tools – need to be promoted through regular communication and dialogue at all levels, including between farmers, seed producers and breeders (about the preferred traits for improved varieties and any challenges farmers are facing), and between stakeholders (to ensure alignment on the goals of seed quality assurance, how to ensure quality, and how to address problems)

Optimizing Parametric Factors in CIELAB and CIEDE2000 Color-Difference Formulas for 3D-Printed Spherical Objects

The current color-difference formulas were developed based on 2D samples and there is no standard guidance for the color-difference evaluation of 3D objects. The aim of this study was to test and optimize the CIELAB and CIEDE2000 color-difference formulas by using 42 pairs of 3D-printed spherical samples in Experiment I and 40 sample pairs in Experiment II. Fifteen human observers with normal color vision were invited to attend the visual experiments under simulated D65 illumination and assess the color differences of the 82 pairs of 3D spherical samples using the gray-scale method. The performances of the CIELAB and CIEDE2000 formulas were quantified by the STRESS index and F-test with respect to the collected visual results and three different optimization methods were performed on the original color-difference formulas by using the data from the 42 sample pairs in Experiment I. It was found that the optimum parametric factors for CIELAB were kL = 1.4 and kC = 1.9, whereas for CIEDE2000, kL = 1.5. The visual data of the 40 sample pairs in Experiment II were used to test the performance of the optimized formulas and the STRESS values obtained for CIELAB/CIEDE2000 were 32.8/32.9 for the original formulas and 25.3/25.4 for the optimized formulas. The F-test results indicated that a significant improvement was achieved using the proposed optimization of the parametric factors applied to both color-difference formulas for 3D-printed spherical samples

Multi-objective design optimisation:Getting more for less

Belgium Herbarium image of Meise Botanic Garden