Fire history reconstruction in grassland ecosystems: amount of charcoal reflects local area burned

Citation: Leys, B., Brewer, S. C., McConaghy, S., Mueller, J., & McLauchlan, K. K. (2015). Fire history reconstruction in grassland ecosystems: amount of charcoal reflects local area burned. Environmental Research Letters, 10(11), 114009. https://doi.org/10.1088/1748-9326/10/11/114009Fire is one of the most prevalent disturbances in the Earth system, and its past characteristics can be reconstructed using charcoal particles preserved in depositional environments. Although researchers know that fires produce charcoal particles, interpretation of the quantity or composition of charcoal particles in terms of fire source remains poorly understood. In this study, we used a unique four-year dataset of charcoal deposited in traps from a native tallgrass prairie in mid-North America to test which environmental factors were linked to charcoal measurements on three spatial scales. We investigated small and large charcoal particles commonly used as a proxy of fire activity at different spatial scales, and charcoal morphotypes representing different types of fuel. We found that small (125–250 μ m) and large (250 μ m–1 mm) particles of charcoal are well-correlated (Spearman correlation = 0.88) and likely reflect the same spatial scale of fire activity in a system with both herbaceous and woody fuels. There was no significant relationship between charcoal pieces and fire parameters <500 m from the traps. Moreover, local area burned (<5 km distance radius from traps) explained the total charcoal amount, and regional burning (200 km radius distance from traps) explained the ratio of non arboreal to total charcoal (NA/ T ratio). Charcoal variables, including total charcoal count and NA/ T ratio, did not correlate with other fire parameters, vegetation cover, landscape, or climate variables. Thus, in long-term studies that involve fire history reconstructions, total charcoal particles, even of a small size (125–250 μ m), could be an indicator of local area burned. Further studies may determine relationships among amount of charcoal recorded, fire intensity, vegetation cover, and climatic parameters

State Power and Economic Inefficiency : Explaining Political Failture in Africa

SUMMARY The problem of agricultural crisis in Africa has forced a review of the highly centralised and bureaucratised structures used to provide services to farmers since independence, and has resulted in a return to favour of decentralised market mechanisms. This article traces the historical evolution of the present system in the colonial period, and sets out the theoretical and political assumptions which lay behind its retention in the post?colonial period. It then attempts to account for current failures by examining the theoretical inconsistencies and actual conflicts of interest involved in the attempt to use these structures in the political, economic and social conditions prevailing in post?colonial Africa. It concludes by recommending a more flexible approach based upon the use of decentralised private and cooperative structures directly accountable to the farmers who use them. SOMMAIRE Le problème de la crise agricole en Afrique a forcé une révision des structures bureaucratìques et hautement centralisées, utilisées pour procurer des services aux fermiers depuis l'indépendance, ceci a eu pour résultat de plaider en faveur des mécanismes de marché décentralisées. Cet article trace révolution historique du système actuel dans la période coloniale, et présente les assomptions qui sont derrière son maintien dans la période post?coloniale. On tente ensuite d'expliquer les échecs récents en analysant les contradictions théoriques et les conflits d'intérêt actuels impliqués dans les tentatives d'utiliser ces structures sous des conditions politiques, économiques et sociales prévalant dans l'Afrique post?coloniale. L'article conclut en recommandant une approche plus flexible, basée sur l'utilisation de structures privées décentralisées et des structures coopératives imputables aux fermiers utilisateurs. RESUMEN El problema de la crisis agrícola en Africa ha forzado a una revisión de las estructuras altamente centralizadas y burocráticas utilizadas para proporcionar servicios a los agricultores, resultando en un retorno en favor de los mecanismos descentralizados del mercado. Este artículo describe la evolución histórica del sistema actual en el periodo colonial y establece las hipótesis teóricas y políticas que yacen por detrás de su persistencia en el periodo post?colonial. A continuación intenta explicar los fracasos actuales mediante el examen de las incoherencias teóricas y los conflictos de intereses involucrados en el propósito de utilizar estas estructuras en las condiciones políticas, sociales y económicas prevalecientes en Africa post?colonial. Concluye recomendando un enfoque más flexible basado en el uso de estructuras descentralizadas, tanto privadas como cooperativas, directamente responsables ante los granjeros que las utilizan

Bodily Complexity:Integrated Multicellular Organizations for Contraction-Based Motility

Compared to other forms of multicellularity, the animal case is unique. Animals—barring some exceptions—consist of collections of cells that are connected and integrated to such an extent that these collectives act as unitary, large free-moving entities capable of sensing macroscopic properties and events. This animal configuration is so well known that it is often taken as a natural one that ‘must’ have evolved, given environmental conditions that make large free-moving units ‘obviously’ adaptive. Here we question the seemingly evolutionary inevitableness of animals and introduce a thesis of bodily complexity: The multicellular organization characteristic for typical animals requires the integration of a multitude of intrinsic bodily features between its sensorimotor, physiological, and developmental aspects, and the related contraction-based tissue- and cellular-level events and processes. The evolutionary road toward this bodily complexity involves, we argue, various intermediate organizational steps that accompany and support the wider transition from cilia-based to contraction/muscle-based motility, and which remain insufficiently acknowledged. Here, we stress the crucial and specific role played by muscle-based and myoepithelial tissue contraction—acting as a physical platform for organizing both the multicellular transmission of mechanical forces and multicellular signaling—as key foundation of animal motility, sensing and maintenance, and development. We illustrate and discuss these bodily features in the context of the four basal animal phyla—Porifera, Ctenophores, Placozoans, and Cnidarians—that split off before the bilaterians, a supergroup that incorporates all complex animals

In the dedicated pursuit of dedicated capital: restoring an indigenous investment ethic to British capitalism

Tony Blair’s landslide electoral victory on May 1 (New Labour Day?) presents the party in power with a rare, perhaps even unprecedented, opportunity to revitalise and modernise Britain’s ailing and antiquated manufacturing economy.* If it is to do so, it must remain true to its long-standing (indeed, historic) commitment to restore an indigenous investment ethic to British capitalism. In this paper we argue that this in turn requires that the party reject the very neo-liberal orthodoxies which it offered to the electorate as evidence of its competence, moderation and ‘modernisation’, which is has internalised, and which it apparently now views as circumscribing the parameters of the politically and economically possible

Thinking like a man? The cultures of science

Culture includes science and science includes culture, but conflicts between the two traditions persist, often seen as clashes between interpretation and knowledge. One way of highlighting this false polarity has been to explore the gendered symbolism of science. Feminism has contributed to science studies and the critical interrogation of knowledge, aware that practical knowledge and scientific understanding have never been synonymous. Persisting notions of an underlying unity to scientific endeavour have often impeded rather than fostered the useful application of knowledge. This has been particularly evident in the recent rise of molecular biology, with its delusory dream of the total conquest of disease. It is equally prominent in evolutionary psychology, with its renewed attempts to depict the fundamental basis of sex differences. Wars over science have continued to intensify over the last decade, even as our knowledge of the political, economic and ideological significance of science funding and research has become ever more apparent

Production, characterization and determination of the real catalytic properties of the putative ‘succinate dehydrogenase’ from Wolinella succinogenes

Both the genomes of the epsilonproteobacteria Wolinella succinogenes and Campylobacter jejuni contain operons (sdhABE) that encode for so far uncharacterized enzyme complexes annotated as ‘non-classical’ succinate:quinone reductases (SQRs). However, the role of such an enzyme ostensibly involved in aerobic respiration in an anaerobic organism such as W. succinogenes has hitherto been unknown. We have established the first genetic system for the manipulation and production of a member of the non-classical succinate:quinone oxidoreductase family. Biochemical characterization of the W. succinogenes enzyme reveals that the putative SQR is in fact a novel methylmenaquinol:fumarate reductase (MFR) with no detectable succinate oxidation activity, clearly indicative of its involvement in anaerobic metabolism. We demonstrate that the hydrophilic subunits of the MFR complex are, in contrast to all other previously characterized members of the superfamily, exported into the periplasm via the twin-arginine translocation (tat)-pathway. Furthermore we show that a single amino acid exchange (Ala86→His) in the flavoprotein of that enzyme complex is the only additional requirement for the covalent binding of the otherwise non-covalently bound FAD. Our results provide an explanation for the previously published puzzling observation that the C. jejuni sdhABE operon is upregulated in an oxygen-limited environment as compared with microaerophilic laboratory conditions

Examining the effect of teachers' adaptations of a middle school science inquiry-oriented curriculum unit on student learning

Reform based curriculum offer a promising avenue to support greater student achievement in science. Yet teachers frequently adapt innovative curriculum when they use them in their own classrooms. In this study, we examine how 19 teachers adapted an inquiry-oriented middle school science curriculum. Specifically, we investigate how teachers' curricular adaptations (amount of time, level of completion, and activity structures), teacher self-efficacy (teacher comfort and student understanding), and teacher experience enacting the unit influenced student learning. Data sources included curriculum surveys, videotape observations of focal teachers, and pre- and post-tests from 1,234 students. Our analyses using hierarchical linear modeling found that 38% of the variance in student gain scores occurred between teachers. Two variables significantly predicted student learning: teacher experience and activity structure. Teachers who had previously taught the inquiry-oriented curriculum had greater student gains. For activity structure, students who completed investigations themselves had greater learning gains compared to students in classrooms who observed their teacher completing the investigations as demonstrations. These findings suggest that it can take time for teachers to effectively use innovative science curriculum. Furthermore, this study provides evidence for the importance of having students actively engaging in inquiry investigations to develop understandings of key science concepts. © 2010 Wiley Periodicals, Inc., J Res Sci Teach 48: 149–169, 2011Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79436/1/20399_ftp.pd

Cloning and Characterization of Genes Involved in Nostoxanthin Biosynthesis of Sphingomonas elodea ATCC 31461

Most Sphingomonas species synthesize the yellow carotenoid nostoxanthin. However, the carotenoid biosynthetic pathway of these species remains unclear. In this study, we cloned and characterized a carotenoid biosynthesis gene cluster containing four carotenogenic genes (crtG, crtY, crtI and crtB) and a β-carotene hydroxylase gene (crtZ) located outside the cluster, from the gellan-gum producing bacterium Sphingomonas elodea ATCC 31461. Each of these genes was inactivated, and the biochemical function of each gene was confirmed based on chromatographic and spectroscopic analysis of the intermediates accumulated in the knockout mutants. Moreover, the crtG gene encoding the 2,2′-β-hydroxylase and the crtZ gene encoding the β-carotene hydroxylase, both responsible for hydroxylation of β-carotene, were confirmed by complementation studies using Escherichia coli producing different carotenoids. Expression of crtG in zeaxanthin and β-carotene accumulating E. coli cells resulted in the formation of nostoxanthin and 2,2′-dihydroxy-β-carotene, respectively. Based on these results, a biochemical pathway for synthesis of nostoxanthin in S. elodea ATCC 31461 is proposed

The Parkinsonian subthalamic network: measures of power, linear, and non-linear synchronization and their relationship to L-DOPA treatment and OFF state motor severity

In this paper we investigated the dopaminergic modulation of neuronal interactions occurring in the subthalamic nucleus (STN) during Parkinson's disease (PD). We utilized linear measures of local and long range synchrony such as power and coherence, as well as Detrended Fluctuation Analysis for Phase Synchrony (DFA-PS)- a recently developed non-linear method that computes the extent of long tailed autocorrelations present in the phase interactions between two coupled signals. Through analysis of local field potentials (LFPs) taken from the STN we seek to determine changes in the neurodynamics that may underpin the pathophysiology of PD in a group of 12 patients who had undergone surgery for deep brain stimulation. We demonstrate up modulation of alpha-theta (5–12 Hz) band power in response to L-DOPA treatment, whilst low beta band power (15–20 Hz) band-power is suppressed. We also find evidence for significant local connectivity within the region surrounding STN although there was evidence for its modulation via administration of L-DOPA. Further to this we present evidence for a positive correlation between the phase ordering of bilateral STN interactions and the severity of bradykinetic and rigidity symptoms in PD. Although, the ability of non-linear measures to predict clinical state did not exceed standard measures such as beta power, these measures may help identify the connections which play a role in pathological dynamics