499 research outputs found
Finding a way out: Proustian semiotics in Deleuze and Guattari
We argue in this article that Gilles Deleuzeâs Proust et les signes, itself consisting of three chronologically separate instalments, should be seen in tandem with a later analysis of Marcel Proustâs Ă la recherche du temps perdu in FĂŠlix Guattariâs LâInconscient machinique, and that, taken as a complex assemblage, these interventions cohere around a radical exit from the reign of the linguistic signifier and thus from a semiotics based on the primacy of language. Proustian semiotics, as rendered by Deleuze and Guattari, is âantilogosâ, both in its shattering of any single signsystem, and in the proposition of the dimension of pathos, which accompanies and undermines discursive surety
Financial stability and the Trans-Pacific Partnership: lessons from Chile and Malaysia
This repository item contains a working paper from the Boston University Global Economic Governance Initiative. The Global Economic Governance Initiative (GEGI) is a research program of the Center for Finance, Law & Policy, the Frederick S. Pardee Center for the Study of the Longer-Range Future, and the Frederick S. Pardee School of Global Studies. It was founded in 2008 to advance policy-relevant knowledge about governance for financial stability, human development, and the environment.There is growing recognition that nations may need to deploy cross-border financial regulations
to prevent and mitigate financial crises. Indeed, in December of 2012 the International Monetary
Fund (IMF) agreed on a new âinstitutional viewâ that notes how the IMF will begin to recommend
that nations deploy cross-border financial regulations going forward. However, many nations
have become party to global, regional, and bi-lateral trade and investment treaties that may
restrict their ability to effectively deploy such regulations.
This paper examines the cases of two countries currently in negotiations for a Trans-Pacific
Partnership Agreement (TPP): Chile and Malaysia. The paper examines the extent to which each
nation has deployed cross-border financial regulations in the past, and the extent to which they
have negotiated the policy space for such regulations in its previous trade and investment treaties.
Finally, it analyzes the extent to which such measures would be permitted if the TPPâs investment
provisions looked like the model bi-lateral investment treaty of the United States.
We find that, with some important exceptions, both countries have successfully deployed crossborder
financial regulations and have carved out the ability to do so under a sample of
representative trading commitments. However, such policy space would be jeopardized if the
TPP conformed to the US model rather than arrangements that each country has been able to
broker in other arenas
Microsatellites for the marsh fritillary butterfly: de novo transcriptome sequencing, and a comparison with amplified fragment length polymorphism (AFLP) markers.
Journal ArticleResearch Support, Non-U.S. Gov'tBACKGROUND: Until recently the isolation of microsatellite markers from Lepidoptera has proved troublesome, expensive and time-consuming. Following on from a previous study of Edith's checkerspot butterfly, Euphydryas editha, we developed novel microsatellite markers for the vulnerable marsh fritillary butterfly, E. aurinia. Our goal was to optimize the process in order to reduce both time and cost relative to prevailing techniques. This was accomplished by using a combination of previously developed techniques: in silico mining of a de novo assembled transcriptome sequence, and genotyping the microsatellites found there using an economic method of fluorescently labelling primers. PRINCIPAL FINDINGS: In total, we screened nine polymorphic microsatellite markers, two of which were previously published, and seven that were isolated de novo. These markers were able to amplify across geographically isolated populations throughout Continental Europe and the UK. Significant deviations from Hardy-Weinberg equilibrium were evident in some populations, most likely due to the presence of null alleles. However, we used an F(st) outlier approach to show that these markers are likely selectively neutral. Furthermore, using a set of 128 individuals from 11 populations, we demonstrate consistency in population differentiation estimates with previously developed amplified fragment length polymorphism (AFLP) markers (r = 0.68, p<0.001). SIGNIFICANCE: Rapid development of microsatellite markers for difficult taxa such as Lepidoptera, and concordant results with other putatively neutral molecular markers, demonstrate the potential of de novo transcriptional sequencing for future studies of population structure and gene flow that are desperately needed for declining species across fragmented landscapes.BBSRCOkinawa Institute for Science and Technology (OIST
A neo-W chromosome in a tropical butterfly links colour pattern, male-killing, and speciation
PublishedJournal ArticleŠ 2016, Royal Society of London. All rights reserved.Sexually antagonistic selection can drive both the evolution of sex chromosomes and speciation itself. The tropical butterfly the African Queen, Danaus chrysippus, shows two such sexually antagonistic phenotypes, the first being sex-linked colour pattern, the second, susceptibility to a male-killing, maternally inherited mollicute, Spiroplasma ixodeti, which causes approximately 100% mortality in male eggs and first instar larvae. Importantly, this mortality is not affected by the infection status of the male parent and the horizontal transmission of Spiroplasma is unknown. In East Africa, male-killing of the Queen is prevalent in a narrow hybrid zone centred on Nairobi. This hybrid zone separates otherwise allopatric subspecies with different colour patterns. Here we show that a neo-W chromosome, a fusion between the W (female) chromosome and an autosome that controls both colour pattern and malekilling, links the two phenotypes thereby driving speciation across the hybrid zone. Studies of the population genetics of the neo-W around Nairobi showthat the interaction between colour pattern and male-killer susceptibility restricts gene flow between two subspecies of D. chrysippus. Our results demonstrate how a complex interplay between sex, colour pattern, malekilling, and a neo-W chromosome, has set up a genetic âsinkâ that keeps the two subspecies apart. The association between the neo-W and male-killing thus provides a âsmoking gunâ for an ongoing speciation process.Matt McClements (Blink Studios Ltd) designed the figures, Bernard Rono assisted with fieldwork, and Samuel Katoi provided specimens from Watamu. Fieldwork at Silole Sanctuary (Kitengela) was sanctioned by Nani Croze, Eric Krystall, John Keen, and Mark van Rampelberg. Simon Martin scrutinized the first draft of the manuscript and made valuable suggestions for its improvement. Spiroplasma screening was carried out at icipe. D.A.S.S. thanks the Linnean Society of London and the Outreach Fund of the Royal Entomological Society of London for funding. I.J.G., D.A.S.S., W.T., and K.S. are Research Affiliates of the National Museums of Kenya
Pyrosequencing the transcriptome of the greenhouse whitefly, Trialeurodes vaporariorum reveals multiple transcripts encoding insecticide targets and detoxifying enzymes.
Published onlineJournal ArticleResearch Support, Non-U.S. Gov'tBACKGROUND: The whitefly Trialeurodes vaporariorum is an economically important crop pest in temperate regions that has developed resistance to most classes of insecticides. However, the molecular mechanisms underlying resistance have not been characterised and, to date, progress has been hampered by a lack of nucleotide sequence data for this species. Here, we use pyrosequencing on the Roche 454-FLX platform to produce a substantial and annotated EST dataset. This 'unigene set' will form a critical reference point for quantitation of over-expressed messages via digital transcriptomics. RESULTS: Pyrosequencing produced around a million sequencing reads that assembled into 54,748 contigs, with an average length of 965 bp, representing a dramatic expansion of existing cDNA sequences available for T. vaporariorum (only 43 entries in GenBank at the time of this publication). BLAST searching of non-redundant databases returned 20,333 significant matches and those gene families potentially encoding gene products involved in insecticide resistance were manually curated and annotated. These include, enzymes potentially involved in the detoxification of xenobiotics and those encoding the targets of the major chemical classes of insecticides. A total of 57 P450s, 17 GSTs and 27 CCEs were identified along with 30 contigs encoding the target proteins of six different insecticide classes. CONCLUSION: Here, we have developed new transcriptomic resources for T. vaporariorum. These include a substantial and annotated EST dataset that will serve the community studying this important crop pest and will elucidate further the molecular mechanisms underlying insecticide resistance.CASE PhD studentship BBSRCBayer CropScienceRothamsted Researc
Macroeconomic stability and investment allocation of domestic pension funds in emerging economies: the case of Chile
Includes bibliograph
Oligodendrocyte HCN2 channels regulate myelin sheath length
Oligodendrocytes generate myelin sheaths vital for the formation, health and function of the central nervous system (CNS). Myelin sheath length is a key property that determines axonal conduction velocity and is known to be variable across the CNS. Myelin sheath length can be modified by neuronal activity, suggesting that dynamic regulation of sheath length might contribute to the functional plasticity of neural circuits. Although the mechanisms that establish and refine myelin sheath length are important determinants of brain function, our understanding of these remains limited. In recent years, the membranes of myelin sheaths have been increasingly recognised to contain ion channels and transporters that are associated with specific important oligodendrocyte functions, including metabolic support of axons and the regulation of ion homeostasis, but none have been shown to influence sheath architecture. In this study, we determined that hyperpolarisation-activated, cyclic nucleotide-gated (HCN) channels, typically associated with neuronal and cardiac excitability, regulate myelin sheath length. Using both in vivo and in vitro approaches, we show that oligodendrocytes abundantly express functional, predominantly HCN2 subunit-containing channels. These HCN channels retain key pharmacological and biophysical features and regulate the resting membrane potential of myelinating oligodendrocytes. Further, reduction of their function via pharmacological blockade or generation of transgenic mice with two independent oligodendrocyte-specific HCN2 knock out strategies reduced myelin sheath length. We conclude that HCN2 channels are key determinants of myelin sheath length in the CNS
African queens find mates when males are rare
This is the final version. Available from Wiley via the DOI in this record.âŻDATA AVAILABILITY STATEMENT:
Sex ratio, spermatophore numbers and Rcode: Figshare doi:10.6084/
m9.figshare.21947729.In butterflies and moths, male-killing endosymbionts are transmitted from infected females via their eggs, and the male progeny then perish. This means that successful transmission of the parasite relies on the successful mating of the host. Paradoxically, at the population level, parasite transmission also reduces the number of adult males present in the final population for infected females to mate with. Here we investigate if successful female mating when males are rare is indeed a likely rate-limiting step in the transmission of male-killing Spiroplasma in the African Monarch, Danaus chrysippus. In Lepidoptera, successful pairings are hallmarked by the transfer of a sperm-containing spermatophore from the male to the female during copulation. Conveniently, this spermatophore remains detectable within the female upon dissection, and thus, spermatophore counts can be used to assess the frequency of successful mating in the field. We used such spermatophore counts to examine if altered sex ratios in the D. chrysippus do indeed affect female mating success. We examined two different field sites in East Africa where males were often rare. Surprisingly, mated females carried an average of 1.5 spermatophores each, regardless of male frequency, and importantly, only 10-20% remained unmated. This suggests that infected females will still be able to mate in the face of either Spiroplasma-mediated male killing and/or fluctuations in adult sex ratio over the wet-dry season cycle. These observations may begin to explain how the male-killing mollicute can still be successfully transmitted in a population where males are rare.National Geographic SocietyRoyal Societ
Neo sex chromosomes, colour polymorphism and male-killing in the African queen butterfly, Danaus chrysippus (L.)
This is the final version. Available from MDPI via the DOI in this record.âŻThe following are available online at http://www.mdpi.com/2075-4450/10/9/291/s1, Figure S1: (a) Histograms showing the frequencies (per cent) of (A) females and (BâD) the three homozygous recessive phenotypes aa (B), bb (C) and cc (D) at Nairobi. Symbols on the co-ordinate: J = January, F = February, A = Insects 2019, 10, 291 20 of 25 April, M = May, J/A = July/August, N = November. x = the mean value of the six samples [13]; (b) Frequencies (per cent) as three-month moving averages for the cc genotype (o) and females (â˘) in monthly samples of D.chrysippus from February 1972 to September 1975 on the campus of the University of Dar es Salaam, Tanzania. The approximate durations of wet seasons (dashed lines indicating periods that are variable) and the two monsoons (SE = southâeast, NE = northâeast) are shown at the top [13]; Table S1: Sex ratios of Danaus chrysippus collected as eggs, Athi River Plains, Nairobi, 1986â1994. (Expected numbers if the true sex ratio is stable at 74.5% female in parentheses); Table S2: Disassortative (negative non-random) mating for C locus genotype (expected numbers in parentheses if mate choice is random) in D. chrysippus at Kitengela, Kenya, MayâJuly 2015.Danaus chrysippus (L.), one of the worldâs commonest butterflies, has an extensive range throughout the Old-World tropics. In Africa it is divided into four geographical subspecies which overlap and hybridise freely in the East African Rift: Here alone a male-killing (MK) endosymbiont, Spiroplasma ixodetis, has invaded, causing female-biased populations to predominate. In ssp. chrysippus, inside the Rift only, an autosome carrying a colour locus has fused with the W chromosome to create a neo-W chromosome. A total of 40-100% of Rift females are neo-W and carry Spiroplasma, thus transmitting a linked, matrilineal neo-W, MK complex. As neo-W females have no sons, half the motherâs genes are lost in each generation. Paradoxically, although neo-W females have no close male relatives and are thereby forced to outbreed, MK restricts gene flow between subspecies and may thus promote speciation. The neo-W chromosome originated in the Nairobi region around 2.2 k years ago and subsequently spread throughout the Rift contact zone in some 26 k generations, possibly assisted by not having any competing brothers. Our work on the neo-W chromosome, the spread of Spiroplasma and possible speciation is ongoing
Do populismo Ă s bandas cambiais: a evolução da polĂtica cambial no Chile de 1970 a 1999
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