418 research outputs found
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De una Policia Centrada en el estado a una centrada en la comunidad. Lecciones del Intercambio entre las Policías Comunitarias de Bradford en el Reino Unido y de Medellín en Colombia.
yesEste documento de investigación del ICPS es un reporte final de un proceso de cuatro años,
en el que se realizaron visitas de intercambio entre oficiales de policía de dos distintos pero
problemáticos contextos urbanos, así como una reflexión académica sobre lo que nos enseñó
acerca de la construcción de seguridad en tales contextos. Esperamos estimular una mayor
discusión en el campo académico y en el diseño de políticas para sobrepasar los obstáculos a
la construcción de seguridad en nuestras ciudades en formas que contribuyan al bienestar, la
paz y la justicia social. Nuestro trabajo en el Centro Internacional de Estudios en
Participación de la Universidad de Bradford se concentra especialmente en el estudio de
cómo mejores condiciones de seguridad pueden promover y permitirle a la comunidad tener
un rol completo en la vida pública. Creemos que la seguridad debe estar en el centro de los
estudios de paz con sólidas dimensiones teóricas y prácticas. Este no es un concepto que deba
ser dejado a los pensadores conservadores cuya principal preocupación son el orden y la
estabilidad. La seguridad crea ambientes que posibilitan cambios sociales positivos y
progreso humano
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Security Provision and Governing Processes in Fragile Cities of the Global South: The case of Medellin 2002-2012
The incidence of violence and the configuration of areas of instability, which have accompanied rapid urbanisation processes in the global South, have led to a wide range of responses by state authorities at different levels. These responses include attempts to control, prevent and/or manage various forms of violence and crime. An emerging literature on urban security aims to improve our understanding of public security provision in volatile urban contexts in the global South. This literature has so far been dominated by policy-oriented and state-centric analyses, as well as by critiques of the way neoliberal governance is shaping responses to urban instability. These analytical approaches tend to ignore the political aspects and governmental consequences of security provision in fragile cities. This thesis argues that Foucault’s work on governmentality and ethnographic methodologies offer analytical and methodological tools that can help us address limitations in predominant analytical frameworks and contribute to fill gaps in the literature. The thesis develops an alternative critical approach to the study of urban security using those tools and employs it to investigate security provision in Medellin. This alternative approach focuses on the way security shapes governing processes in particular contexts and on their implications for those who are most vulnerable to urban fragility. Moreover, the thesis uses this innovative approach to investigate the security strategy implemented in Medellin since 2002, as part of what has come to be known as the ‘Medellin Model’. By exploring this particularly relevant case, this thesis highlights the significance of undertaking empirical explorations of the rationality of security strategies in different urban contexts and the importance of taking into account people´s differentiated experiences of security provision. Furthermore, this thesis argues that this alternative approach helps us understand the way power is exercised for particular purposes and on particular subjects in an attempt to deal with urban violence and insecurity. It also argues for the inclusion of these dimensions in contemporary studies of urban security in the global South
Lattice Model for water-solute mixtures
A lattice model for the study of mixtures of associating liquids is proposed.
Solvent and solute are modeled by adapting the associating lattice gas (ALG)
model. The nature of interaction solute/solvent is controlled by tuning the
energy interactions between the patches of ALG model. We have studied three set
of parameters, resulting on, hydrophilic, inert and hydrophobic interactions.
Extensive Monte Carlo simulations were carried out and the behavior of pure
components and the excess properties of the mixtures have been studied. The
pure components: water (solvent) and solute, have quite similar phase diagrams,
presenting: gas, low density liquid, and high density liquid phases. In the
case of solute, the regions of coexistence are substantially reduced when
compared with both the water and the standard ALG models. A numerical procedure
has been developed in order to attain series of results at constant pressure
from simulations of the lattice gas model in the grand canonical ensemble. The
excess properties of the mixtures: volume and enthalpy as the function of the
solute fraction have been studied for different interaction parameters of the
model. Our model is able to reproduce qualitatively well the excess volume and
enthalpy for different aqueous solutions. For the hydrophilic case, we show
that the model is able to reproduce the excess volume and enthalpy of mixtures
of small alcohols and amines. The inert case reproduces the behavior of large
alcohols such as, propanol, butanol and pentanol. For last case (hydrophobic),
the excess properties reproduce the behavior of ionic liquids in aqueous
solution.Comment: 28 pages, 13 figure
Profiling of a high mannose-type N-glycosylated lipase using hydrophilic interaction chromatography-mass spectrometry
Many industrial enzymes exhibit macro- and micro-heterogeneity due to co-occurring post-translational modifications. The resulting proteoforms may have different activity and stability and, therefore, the characterization of their distributions is of interest in the development and monitoring of enzyme products. Protein glycosylation may play a critical role as it can influence the expression, physical and biochemical properties of an enzyme. We report the use of hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) to profile intact glycoform distributions of high mannose-type N-glycosylated proteins, using an industrially produced fungal lipase for the food industry as an example. We compared these results with conventional reversed phase LC-MS (RPLC-MS) and sodium dodecyl sulfate-polyacrylamide gel-electrophoresis (SDS-PAGE). HILIC appeared superior in resolving lipase heterogeneity, facilitating mass assignment of N-glycoforms and sequence variants. In order to understand the glycoform selectivity provided by HILIC, fractions from the four main HILIC elution bands for lipase were taken and subjected to SDS-PAGE and bottom-up proteomic analysis. These analyses enabled the identification of the most abundant glycosylation sites present in each fraction and corroborated the capacity of HILIC to separate protein glycoforms based on the number of glycosylation sites occupied. Compared to RPLC-MS, HILIC-MS reducted the sample complexity delivered to the mass spectrometer, facilitating the assignment of the masses of glycoforms and sequence variants as well as increasing the number of glycoforms detected (69 more proteoforms, 177% increase). The HILIC-MS method required relatively short analysis time (<30 min), in which over 100 glycoforms were distinguished. We suggest that HILIC(-MS) can be a valuable tool in characterizing bioengineering processes aimed at steering protein glycoform expression as well as to check the consistency of product batche
Does native Trypanosoma cruzi calreticulin mediate growth inhibition of a mammary tumor during infection?
Indexación: Web of Science.Background: For several decades now an antagonism between Trypanosoma cruzi infection and tumor development has been detected. The molecular basis of this phenomenon remained basically unknown until our proposal that T. cruzi Calreticulin (TcCRT), an endoplasmic reticulum-resident chaperone, translocated-externalized by the parasite, may mediate at least an important part of this effect. Thus, recombinant TcCRT (rTcCRT) has important in vivo antiangiogenic and antitumor activities. However, the relevant question whether the in vivo antitumor effect of T. cruzi infection is indeed mediated by the native chaperone (nTcCRT), remains open. Herein, by using specific modified anti-rTcCRT antibodies (Abs), we have neutralized the antitumor activity of T. cruzi infection and extracts thereof, thus identifying nTcCRT as a valid mediator of this effect.
Methods: Polyclonal anti-rTcCRT F(ab')(2) Ab fragments were used to reverse the capacity of rTcCRT to inhibit EAhy926 endothelial cell (EC) proliferation, as detected by BrdU uptake. Using these F(ab')(2) fragments, we also challenged the capacity of nTcCRT, during T. cruzi infection, to inhibit the growth of an aggressive mammary adenocarcinoma cell line (TA3-MTXR) in mice. Moreover, we determined the capacity of anti-rTcCRT Abs to reverse the antitumor effect of an epimastigote extract (EE). Finally, the effects of these treatments on tumor histology were evaluated.
Results: The rTcCRT capacity to inhibit ECs proliferation was reversed by anti-rTcCRT F(ab')(2) Ab fragments, thus defining them as valid probes to interfere in vivo with this important TcCRT function. Consequently, during infection, these Ab fragments also reversed the in vivo experimental mammary tumor growth. Moreover, anti-rTcCRT Abs also neutralized the antitumor effect of an EE, again identifying the chaperone protein as an important mediator of this anti mammary tumor effect. Finally, as determined by conventional histological parameters, in infected animals and in those treated with EE, less invasive tumors were observed while, as expected, treatment with F(ab')(2) Ab fragments increased malignancy.
Conclusion: We have identified translocated/externalized nTcCRT as responsible for at least an important part of the anti mammary tumor effect of the chaperone observed during experimental infections with T. cruzi.http://bmccancer.biomedcentral.com/articles/10.1186/s12885-016-2764-
Random graphs with arbitrary degree distributions and their applications
Recent work on the structure of social networks and the internet has focussed
attention on graphs with distributions of vertex degree that are significantly
different from the Poisson degree distributions that have been widely studied
in the past. In this paper we develop in detail the theory of random graphs
with arbitrary degree distributions. In addition to simple undirected,
unipartite graphs, we examine the properties of directed and bipartite graphs.
Among other results, we derive exact expressions for the position of the phase
transition at which a giant component first forms, the mean component size, the
size of the giant component if there is one, the mean number of vertices a
certain distance away from a randomly chosen vertex, and the average
vertex-vertex distance within a graph. We apply our theory to some real-world
graphs, including the world-wide web and collaboration graphs of scientists and
Fortune 1000 company directors. We demonstrate that in some cases random graphs
with appropriate distributions of vertex degree predict with surprising
accuracy the behavior of the real world, while in others there is a measurable
discrepancy between theory and reality, perhaps indicating the presence of
additional social structure in the network that is not captured by the random
graph.Comment: 19 pages, 11 figures, some new material added in this version along
with minor updates and correction
Correlations in Scale-Free Networks: Tomography and Percolation
We discuss three related models of scale-free networks with the same degree
distribution but different correlation properties. Starting from the
Barabasi-Albert construction based on growth and preferential attachment we
discuss two other networks emerging when randomizing it with respect to links
or nodes. We point out that the Barabasi-Albert model displays dissortative
behavior with respect to the nodes' degrees, while the node-randomized network
shows assortative mixing. These kinds of correlations are visualized by
discussig the shell structure of the networks around their arbitrary node. In
spite of different correlation behavior, all three constructions exhibit
similar percolation properties.Comment: 6 pages, 2 figures; added reference
Electron Capture Dissociation Mass Spectrometry of Tyrosine Nitrated Peptides
In vivo protein nitration is associated with many disease conditions that involve oxidative stress and inflammatory response. The modification involves addition of a nitro group at the position ortho to the phenol group of tyrosine to give 3-nitrotyrosine. To understand the mechanisms and consequences of protein nitration, it is necessary to develop methods for identification of nitrotyrosine-containing proteins and localization of the sites of modification.Here, we have investigated the electron capture dissociation (ECD) and collision-induced association (CID) behavior of 3-nitrotyrosine-containing peptides. The presence of nitration did not affect the CID behavior of the peptides. For the doubly-charged peptides, addition of nitration severely inhibited the production of ECD sequence fragments. However, ECD of the triply-charged nitrated peptides resulted in some singly-charged sequence fragments. ECD of the nitrated peptides is characterized by multiple losses of small neutral species including hydroxyl radicals, water and ammonia. The origin of the neutral losses has been investigated by use of activated ion (AI) ECD. Loss of ammonia appears to be the result of non-covalent interactions between the nitro group and protonated lysine side-chains
I/O-Efficient Algorithms on Near-Planar Graphs
Obtaining I/O-efficient algorithms for basic graph problems on sparse directed graphs is a long-standing open problem. While the best known upper bounds for most basic problems on such graphs with V vertices still require O(V ) I/Os, optimal O(sort (V )) I/O algorithms are known for special classes of sparse graphs, like planar graphs and grid graphs. It is hard to accept that a problem becomes difficult as soon as the graph contains a few deviations from planarity. In this paper we extend the class of graphs on which basic graph problems can be solved I/O-efficiently. We give a characterization of near-planarity which covers a wide range of near-planar graphs, and obtain the first I/O-efficient algorithms for directed graphs that are near-planar
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