Are Cosmological Gas Accretion Streams Multiphase and Turbulent?

Simulations of cosmological filamentary accretion reveal flows ("streams") of warm gas, ~$10^4$ K, which are efficient in bringing gas into galaxies. We present a phenomenological scenario where gas in such flows -- if it is shocked as it enters the halo as we assume -- become biphasic and, as a result, turbulent. We consider a collimated stream of warm gas that flows into a halo from an over dense filament of the cosmic web. The post-shock streaming gas expands because it has a higher pressure than the ambient halo gas, and fragments as it cools. The fragmented stream forms a two phase medium: a warm cloudy phase embedded in hot post-shock gas. We argue that the hot phase sustains the accretion shock. A fraction of the initial kinetic energy of the infalling gas is converted into turbulence among and within the warm clouds. The thermodynamic evolution of the post-shock gas is largely determined by the relative timescales of several processes -- the cooling, the expansion of the post-shock gas, the amount of turbulence in the clouds, and the halo dynamics. We expect the gas to become multiphase when the cooling and dynamical times are of the same order-of-magnitude. In this framework, we show that this occurs in the important mass range of ~$10^{11}$ to $10^{13}$ M$_\odot$ , where the bulk of stars have formed in galaxies. Gas accreting along cosmic web filaments may eventually lose coherence and mix with the ambient halo gas. Through both the phase separation and "disruption" of the stream, the accretion efficiency onto a galaxy in a halo dynamical time is lowered. De-collimating flows make the direct interaction between galaxy feedback and accretion streams more likely, thereby further reducing the overall accretion efficiency. Moderating the gas accretion efficiency through these mechanisms may help to alleviate a number of significant challenges in theoretical galaxy formation.Comment: 13 pages, 8 figures, Submitted to A&A, New version includes new figure

Modelling the Common Agricultural Policy.General equilibrium effects of the 2014-2020 budget agreement

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The EU budget battle: Assessing the trade and welfare impacts of CAP budgetary reform

There is a paucity of quantitative impact assessments of the sectorial and macroeconomic impacts of CAP budget reform for EU member states. To fill this gap, the current study employs a sophisticated agricultural variant of the GTAP model to evaluate the recently agreed CAP spending limits for the financial period 2014–2020 as well as a more radical 50% cut to the CAP budget proposed by the UK government. The study incorporates methodological innovation in terms of the modelling of CAP budgetary mechanisms. Furthermore, official EU auditing statistics are employed to (i) greatly improve the existing representation of agricultural support payments in the GTAP benchmark data and (ii) implement a detailed contemporary CAP baseline for member states to capture both the decoupled/coupled split of support payments and the distribution of support across both ‘pillars’. In general, CAP expenditure cuts have muted impacts on EU and world agricultural markets; whereas changes in net transfer payments have implications for real income and macro trade balances in EU member states. This observation is particularly pertinent when assessing conciliatory reductions in the UK rebate in exchange for deeper CAP budget cuts.Publishe

Rebel group life cycles : the formation, maintenance, and legacies of rebel organizations in Colombia

Les politologues ont récemment commencé à analyser les processus organisationnels et sociaux des guerres civiles. Malgré certains progrès, nous en savons peu sur les trajectoires des insurgés et les processus transperçant le cycle de vie des groupes rebelles. En effet, la plupart des théories négligent la dimension de longue durée des rébellions. Comblant cette lacune, la thèse construit une approche longitudinale des cycles de vie des groupes rebelles. Comment les différentes étapes du cycle de vie d'une organisation rebelle sont-elles liées les unes aux autres? Comment les individus façonnent-ils les organisations rebelles? Comment les individus sont-ils transformés par leur passage au sein de groupes rebelles? Inspiré par la sociologie politique, la thèse soutient que la formation, le maintien et l'héritage des groupes rebelles sont conditionnés par les expériences, mentalités, liens sociaux et compétences des individus composant ces organisations. En retour, la participation au sein des organisations, de sous-unités et à divers rôles transforme les individus, façonnant les dynamiques de guerre et d'après-guerre. La thèse étudie des mécanismes et processus liant les étapes de vie des groupes rebelles, incluant le courtage, le bricolage institutionnel, la légitimation, la trajectoire de vie et la socialisation à vie. L'article I construit une théorie du bricolage dans la formation des groupes rebelles. Dans les milieux hétérogènes, les organisateurs emploient le courtage et le bricolage institutionnel pour renforcer leur capacité opérationnelle. À l’aide de l'analyse des réseaux sociaux et répertoires organisationnels, l’article retrace la formation de la guérilla urbaine du M-19 en Colombie. Les organisateurs de cette guérilla ont recruté des spécialistes de la violence par le courtage et ont réorganisé diverses formes organisationnelles à travers le bricolage institutionnel pour faciliter la coordination interne de l’organisation naissante. L’article II adopte l'approche relationnelle à la légitimité des groupes armés pour étudier la production culturelle et musicale des FARC en Colombie. L'article analyse 258 chansons, des documents internes de la guérilla et des prestations artistiques. L’article démontre que les FARC employaient la production culturelle pour légitimer la hiérarchie interne du groupe et leurs objectifs face aux élites établies et à la population civile. L'article III développe une typologie des trajectoires et des incidences biographiques des ancien.e.s combattant.e.s. L'outil conceptuel permet d’évaluer la position des individus par rapport à la politique, la violence et l'État ainsi que de retracer des dynamiques complexes au sein des trajectoires de vie. Une fois agrégées, les incidences biographiques contribuent à d'importantes dynamiques d'après-guerre. L'article élabore un nouveau programme de recherche portant sur les vies de l’après-guerre civile. L’article IV étudie les processus de socialisation à vie et l’engagement social des ancien.e.s combattant.e.s. L'article emploi une approche biographique pour retracer les trajectoires de 32 ancien.e.s combattant.e.s du M-19. La socialisation au sein des institutions de travail social et d'enseignement, avant le recrutement et pendant la guerre, a conféré aux ancien.e.s combattant.e.s du M-19 des dispositions et des ressources qui, en interaction avec les opportunités post-démobilisation, a façonné leur engagement social. La dissertation offre une vision holistique des cycles de vie des groupes rebelles et étudie des dynamiques liant l’avant, pendant et après guerre. La thèse contribue à notre compréhension des guerres civiles en analysant des processus longitudinaux façonnant les vies des individus, le contenu et la structure des groupes rebelles et les sociétés.Political scientists recently started to analyse the organizational and social processes of civil wars. Despite progress, we know little about the trajectories of insurgents and the processes that span through the life cycle of rebel groups. In fact, most theories neglect the longue durée dimension of rebellions. Filling this gap, this thesis constructs a longitudinal approach to the life cycle of rebel groups. How are different stages in the life cycle of a rebel organization linked to one another? How do individuals shape rebel organizations? How are individuals transformed by their passage through rebel groups? Inspired by political sociology, the thesis argues that the formation, maintenance and legacy of rebel groups are conditioned by the experiences, mindsets, social ties and skills of individuals composing those organizations. In turn, participation in organizations, subunits and roles transform individuals, shaping wartime and post-war dynamics. The thesis studies mechanisms and processes linking insurgent group life stages, including brokerage, institutional bricolage, legitimation, life trajectory, and lifelong socialization. Article I constructs a theory of bricolage in rebel group formation. In heterogeneous environments, rebel organizers employ brokerage and institutional bricolage to build operational capacity. The article employs social network analysis and the analysis of organizational repertoires to retrace the formation of the M-19 urban guerrilla in Colombia. M-19 organizers recruited violent specialists through brokerage, and reorganized various organizational forms through institutional bricolage to facilitate internal coordination in the nascent organization. Article II employs the relational approach to armed group legitimacy to study cultural and music production within the FARC guerrilla in Colombia. The article analyses 258 songs, guerrilla internal documents, and artistic performances. It shows that FARC’s cultural production was employed to legitimize the group’s internal hierarchy and its goals in relation to established elites and the civilian population. Article III develops a typology of ex-combatant trajectories and biographical outcomes. The conceptual tool can be used to assess the position of individuals in relation to politics, violence and the state and track complex dynamics in life trajectories. When aggregated, biographical outcomes contribute to important post-war dynamics. The article elaborates a new research agenda on civil war afterlives. Article IV investigates lifelong socialization processes and social engagement amongst ex-combatants. The article employs a biographical approach to study the trajectories of 32 M-19 ex-combatants. Socialization in social work and education institutions in pre-recruitment and wartime life stages provided M-19 ex-combatants with dispositions and resources that, in interaction with post-demobilization opportunities, shaped their social engagement. The dissertation provides a holistic view of rebel group life cycles and studies dynamics linking prewar, wartime and post-war stages. The thesis contributes to our understanding of civil wars by analysing longitudinal processes shaping individual lives, the content and structure of rebel groups and societies.Recientemente politólog@s han empezado a analizar los diferentes procesos organizativos y sociales de las guerras civiles. A pesar de los avances, sabemos poco sobre las trayectorias de los insurgentes y los procesos que comprenden el ciclo de vida de grupos rebeldes. De hecho, la mayoría de las teorías omiten la dimensión a largo plazo. Llenando este vacío, esta tesis desarrolla una teoría longitudinal de ciclos de vida de grupos rebeldes. ¿Cómo se conectan las diferentes etapas del ciclo de vida de una organización rebelde? ¿Cómo los individuos dan forma a las organizaciones rebeldes? ¿Cómo se transforman los individuos durante su participación en grupos rebeldes? Inspirándose en la sociología política, la tesis argumenta que la formación, el mantenimiento y el legado de los grupos rebeldes están condicionados por las experiencias, mentalidades, vínculos sociales y habilidades individuales de sus participantes. Asimismo, su involucramiento en organizaciones, subunidades y roles también transforma los individuos, moldeando así las dinámicas de guerra y posguerra. Esta tesis estudia mecanismos y procesos que relacionan las etapas de vida de los grupos rebeldes, incluyendo la intermediación, el bricolaje institucional, la legitimación, la trayectoria de vida y la socialización vitalicia. El artículo I construye una teoría de bricolaje en la formación de grupos rebeldes. En entornos heterogéneos, los organizadores recurren a la intermediación y el bricolaje institucional para fortalecer su capacidad operativa. Utilizando el análisis de redes sociales y repertorios organizativos, el artículo rastrea la formación de la guerrilla urbana del M-19 en Colombia. Los organizadores del M-19 reclutaron especialistas en violencia a través de la intermediación y reorganizaron varias formas organizativas con el bricolaje institucional para facilitar la coordinación interna de la organización emergente. El artículo II emplea el enfoque relacional de la legitimidad de los grupos armados para estudiar la producción cultural y musical de las FARC en Colombia. El artículo analiza 258 canciones, documentos internos de la guerrilla y actuaciones artísticas. El trabajo demuestra que las FARC empleaban la producción cultural para legitimar la jerarquía interna del grupo y sus objetivos frente a las élites establecidas y la población civil. El artículo III desarrolla una tipología de las trayectorias e implicaciones biográficas de los excombatientes. La herramienta conceptual permite evaluar la posición de los individuos en relación con la política, la violencia y el estado, así como rastrear dinámicas complejas dentro de las trayectorias de vida. Una vez agregadas, las implicaciones biográficas contribuyen a importantes dinámicas posguerra. El artículo establece una nueva agenda de investigación sobre las vidas posguerra civil. El artículo IV estudia los procesos de socialización de por vida y el compromiso social de los excombatientes. El artículo emplea un enfoque biográfico para rastrear las trayectorias de 32 excombatientes del M-19. Socialización en instituciones de trabajo social y educativas, antes del reclutamiento y durante la guerra, proporcionó a los excombatientes del M-19 disposiciones y recursos que, en interacción con las oportunidades posteriores a la desmovilización, influye en su compromiso social. La disertación ofrece una visión holística de los ciclos de vida de grupos rebeldes y explora las dinámicas que atraviesan el pre, durante y posguerra. La tesis contribuye a la comprensión de las guerras civiles analizando los procesos longitudinales que influyen vidas individuales, el contenido y la estructura de grupos rebeldes y sociedades

2020 Common agricultural policy in Spain. General equilibrium effects of a EU28 budget deal

This paper employs a Computable General Equilibrium (CGE) model to assess the effects of the agreed 2014-2020 Common Agricultural Policy (CAP) budget cuts. It illustrates modest impacts on Spanish, European and world agricultural markets, given the non-distortive representation of the CAP.Publishe

Baculovirus display of single chain antibody (scFv) using a novel signal peptide

Background: Cells permissive to virus can become refractory to viral replication upon intracellular expression of single chain fragment variable (scFv) antibodies directed towards viral structural or regulatory proteins, or virus-coded enzymes. For example, an intrabody derived from MH-SVM33, a monoclonal antibody against a conserved C-terminal epitope of the HIV-1 matrix protein (MAp17), was found to exert an inhibitory effect on HIV-1 replication.<p></p> Results: Two versions of MH-SVM33-derived scFv were constructed in recombinant baculoviruses (BVs) and expressed in BV-infected Sf9 cells, N-myristoylation-competent scFvG2/p17 and N-myristoylation-incompetent scFvE2/p17 protein, both carrying a C-terminal HA tag. ScFvG2/p17 expression resulted in an insoluble, membrane-associated protein, whereas scFvE2/p17 was recovered in both soluble and membrane-incorporated forms. When coexpressed with the HIV-1 Pr55Gag precursor, scFvG2/p17 and scFvE2/p17 did not show any detectable negative effect on virus-like particle (VLP) assembly and egress, and both failed to be encapsidated in VLP. However, soluble scFvE2/p17 isolated from Sf9 cell lysates was capable of binding to its specific antigen, in the form of a synthetic p17 peptide or as Gag polyprotein-embedded epitope. Significant amounts of scFvE2/p17 were released in the extracellular medium of BV-infected cells in high-molecular weight, pelletable form. This particulate form corresponded to BV particles displaying scFvE2/p17 molecules, inserted into the BV envelope via the scFv N-terminal region. The BV-displayed scFvE2/p17 molecules were found to be immunologically functional, as they reacted with the C-terminal epitope of MAp17. Fusion of the N-terminal 18 amino acid residues from the scFvE2/p17 sequence (N18E2) to another scFv recognizing CD147 (scFv-M6-1B9) conferred the property of BV-display to the resulting chimeric scFv-N18E2/M6.<p></p> Conclusion: Expression of scFvE2/p17 in insect cells using a BV vector resulted in baculoviral progeny displaying scFvE2/p17. The function required for BV envelope incorporation was carried by the N-terminal octadecapeptide of scFvE2/p17, which acted as a signal peptide for BV display. Fusion of this peptide to the N-terminus of scFv molecules of interest could be applied as a general method for BV-display of scFv in a GP64- and VSV-G-independent manner.<p></p&gt

Assessing potential coupling factors of European decoupled payments with the Modular Agricultural GeNeral Equilibrium Tool (MAGNET)

In 2020, decoupled payments will represent about 42% of the CAP budget (green payments excluded). This report assesses the potential effects of European decoupled payments on farmers' production decisions, prior to a sensitivity analysis of different coupling factors using the Modular Applied GeNeral Equilibrium Tool (MAGNET). Scientific literature reveals different coupling channels such as capitalisation in land value, farmers' risk behaviour, credit accessibility, uncertainty about future policies and labour allocation through which European decoupled payments influence farm choices and thus output. For each of these channels the relevant literature introducing theoretical and empirical assessments is evaluated with the aim of deriving plausible behavioural parameters that improve the representation of decoupled payments in economic simulation models. To capture completely decoupled production behaviour, many CGE models typically represent decoupled payments as a uniform subsidy rate to the land using (agricultural) sectors. Nevertheless based on a thorough review of the literature, it appears that a more suitable modelling approach which caters for heterogeneous member state land markets, may be to split the allocation of decoupled payments. On the one hand, a proportion is committed to land as a function of the capitalisation rate into the rental value, whilst a second tranche is distributed uniformly across all factors, reflecting a balance of different coupling channels. A sensitivity analysis concludes that if one assumes differing degrees of coupling, it does have some implication for output and price results when conducting policy analysis.JRC.D.4-Economics of Agricultur

The impacts of a CAP budget reform on the world economy: A CGE assessment

European agricultural market support and direct payments amount to 44 billion Euros in 2012 – of which farm subsidies represent 40 billion euros. Rural development measures add 13 billion Euros to the European Union (EU) budget devoted to the Common Agricultural Policy (CAP). As a total, roughly 40 per cent of the EU budget aims at funding this sector-based policy. Whereas a CAP reform is expected for the period post-2013, an agreement on the 2014-2020 EU financial framework shall be reached before then. This paper attempts to capture the implications for the EU and third countries of resource reallocations in the CAP budget provision for the period 2014-2020. It employs a sophisticated dynamic variant of the GTAP model, known as the Modular Applied General Equilibrium Tool (MAGNET) model. Given the focus on agri-food markets, a number of additional modelling features are incorporated to capture the peculiarities of agricultural factor markets (e.g. endogenous land supply, heterogeneous land usage; agricultural/non-agricultural factor split) and agricultural policy (e.g. decoupled payments, rural development support). Of particular importance to this study is the comparatively detailed treatment of the CAP budget, with coverage of first and second pillar, where the latter explicitly characterises between five distinct rural development measures (i.e. physical investment, human capacity, agri-environmental, less favoured areas, and wider rural development). Finally, the 'own resources' component of the European budget is also modelled, with associated rebate mechanisms, in order to consider the political economy of European budgetary reform.CGEcommon agricultural policyEuropean budgettradePublishe