Supersymmetric quantum mechanics on the lattice: III. Simulations and algorithms

In the fermion loop formulation the contributions to the partition function naturally separate into topological equivalence classes with a definite sign. This separation forms the basis for an efficient fermion simulation algorithm using a fluctuating open fermion string. It guarantees sufficient tunnelling between the topological sectors, and hence provides a solution to the fermion sign problem affecting systems with broken supersymmetry. Moreover, the algorithm shows no critical slowing down even in the massless limit and can hence handle the massless Goldstino mode emerging in the supersymmetry broken phase. In this paper – the third in a series of three – we present the details of the simulation algorithm and demonstrate its efficiency by means of a few examples.

Content-Aware Delivery of Scalable Video in Network Coding Enabled Named Data Networks

In this work, we propose a novel network coding enabled NDN architecture for the delivery of scalable video. Our scheme utilizes network coding in order to address the problem that arises in the original NDN protocol, where optimal use of the bandwidth and caching resources necessitates the coordination of the forwarding decisions. To optimize the performance of the proposed network coding based NDN protocol and render it appropriate for transmission of scalable video, we devise a novel rate allocation algorithm that decides on the optimal rates of Interest messages sent by clients and intermediate nodes. This algorithm guarantees that the achieved flow of Data objects will maximize the average quality of the video delivered to the client population. To support the handling of Interest messages and Data objects when intermediate nodes perform network coding, we modify the standard NDN protocol and introduce the use of Bloom filters, which store efficiently additional information about the Interest messages and Data objects. The proposed architecture is evaluated for transmission of scalable video over PlanetLab topologies. The evaluation shows that the proposed scheme performs very close to the optimal performance

Service level agreements-driven management of distributed applications in cloud computing environments

Advancements in cloud computing have enabled the proliferation of distributed applications, which require management and control of multiple services. However, without an efficient mechanism for scaling services in response to changing workload conditions, such as number of connected users, application performance might suffer, leading to violations of Service Level Agreements (SLA) and possible inefficient use of hardware resources. Combining dynamic application requirements with the increased use of virtualised computing resources creates a challenging resource Management context for application and cloud-infrastructure owners. In such complex environments, business entities use SLAs as a means for specifying quantitative and qualitative requirements of services. There are several challenges in running distributed enterprise applications in cloud environments, ranging from the instantiation of service VMs in the correct order using an adequate quantity of computing resources, to adapting the number of running services in response to varying external loads, such as number of users. The application owner is interested in finding the optimum amount of computing and network resources to use for ensuring that the performance requirements of all her/his applications are met. She/he is also interested in appropriately scaling the distributed services so that application performance guarantees are maintained even under dynamic workload conditions. Similarly, the infrastructure Providers are interested in optimally provisioning the virtual resources onto the available physical infrastructure so that her/his operational costs are minimized, while maximizing the performance of tenants’ applications. Motivated by the complexities associated with the management and scaling of distributed applications, while satisfying multiple objectives (related to both consumers and providers of cloud resources), this thesis proposes a cloud resource management platform able to dynamically provision and coordinate the various lifecycle actions on both virtual and physical cloud resources using semantically enriched SLAs. The system focuses on dynamic sizing (scaling) of virtual infrastructures composed of virtual machines (VM) bounded application services. We describe several algorithms for adapting the number of VMs allocated to the distributed application in response to changing workload conditions, based on SLA-defined performance guarantees. We also present a framework for dynamic composition of scaling rules for distributed service, which used benchmark-generated application Monitoring traces. We show how these scaling rules can be combined and included into semantic SLAs for controlling allocation of services. We also provide a detailed description of the multi-objective infrastructure resource allocation problem and various approaches to satisfying this problem. We present a resource management system based on a genetic algorithm, which performs allocation of virtual resources, while considering the optimization of multiple criteria. We prove that our approach significantly outperforms reactive VM-scaling algorithms as well as heuristic-based VM-allocation approaches.

Efficient Deployment of Mobile Detectors for Security Applications

We present a real-world problem that arises in security threat detection applications. The problem consists of deploying mobile detectors on moving units that follow predefined routes. Examples of such units are buses, coaches, and trolleys. Due to a limited budget not all available units can be equipped with a detector. The goal is to equip a subset of units such that the utility of the resulting coverage is maximized. Existing methods for detector deployment are designed to place detectors in fixed locations and are therefore not applicable to the problem considered here. We formulate the planning problem as a binary linear program and present a coverage heuristic for generating effective deployments in short CPU time. The heuristic has theoretical performance guarantees for important special cases of the problem. The effectiveness of the coverage heuristic is demonstrated in a computational analysis based on 28 instances that we derived from real-world data.

In vitro differentiation of mouse granulocytes. Programmed Cell Death: Methods and Protocols

Granulocytes are central players of the immune system and, once activated, a tightly controlled balance between effector functions and cell removal by apoptosis guarantees maximal host benefit with least possible collateral damage to healthy tissue. Granulocytes are end-differentiated cells that cannot be maintained in culture for prolonged times. Isolating primary granulocytes is inefficient and challenging when working with mice, and especially so for the lowly abundant eosinophil and basophils subtypes. Here we describe an in vitro protocol to massively expand mouse derived myeloid progenitors and to differentiate them ‘on demand’ and in large numbers into mature neutrophils or basophils.

Gauging MSSM global symmetries and SUSY breaking in de Sitter vacuum

We elaborate on a recent study of a model of supersymmetry breaking we proposed recently, in the presence of a tunable positive cosmological constant, based on a gauged shift symmetry of a string modulus, external to the Standard Model (SM) sector. Here, we identify this symmetry with a global symmetry of the SM and work out the corresponding phenomenology. A particularly attracting possibility is to use a combination of Baryon and Lepton number that contains the known matter parity and guarantees absence of dimension-four and -five operators that violate B and L.

Active JNK-dependent secretion of Drosophila Tyrosyl-tRNA synthetase by loser cells recruits haemocytes during cell competition

Cell competition is a process by which the slow dividing cells (losers) are recognized and eliminated from growing tissues. Loser cells are extruded from the epithelium and engulfed by the haemocytes, the Drosophila macrophages. However, how macrophages identify the dying loser cells is unclear. Here we show that apoptotic loser cells secrete Tyrosyl-tRNA synthetase (TyrRS), which is best known as a core component of the translational machinery. Secreted TyrRS is cleaved by matrix metalloproteinases generating MiniTyr and EMAP fragments. EMAP acts as a guiding cue for macrophage migration in the Drosophila larvae, as it attracts the haemocytes to the apoptotic loser cells. JNK signalling and Kish, a component of the secretory pathway, are autonomously required for the active secretion of TyrRS by the loser cells. Altogether, this mechanism guarantees effective removal of unfit cells from the growing tissue.

Determinants and Effects of Maturity Mismatches in Emerging Markets: Evidence from Bank Level Data

Despite the extensive work on currency mismatches, research on the determinants and effects of maturity mismatches is scarce. In this paper I show that emerging market maturity mismatches are negatively affected by capital inflows and price volatilities. Furthermore, I find that banks with low maturity mismatches are more profitable during crisis periods but less profitable otherwise. The later result implies that banks face a tradeoff between higher returns and risk, hence channeling short term capital into long term loans is caused by cronyism and implicit guarantees rather than the depth of the financial market. The positive relationship between maturity mismatches and price volatility, on the other hand, shows that the banks of countries with high exchange rate and interest rate volatilities can not, or choose not to hedge themselves. These results follow from a panel regression on a data set I constructed by merging bank level data with aggregate data. This is advantageous over traditional studies which focus only on aggregate data.

Entrevista a Angela McRobbie : los estudios culturales y el imperativo de entender y explicar los cambios sociales

Angela McRobbie es socióloga y dirige el Departamento de Comunicación en Goldsmiths College, Universidad de Londres. En la actualidad, se encuentra entre las referentes más destacadas de los Estudios Culturales británicos. Ha publicado numerosos ensayos en revistas internacionales sobre problemáticas vinculadas con la juventud, los estilos musicales y los consumos culturales, así como ha indagado en los cambios sociales y políticos ocurridos desde los tiempos del thatcherismo. Entre sus libros, sobresalen: Postmodernism and Popular Culture (Routledge, 1994); Feminism and Youth Culture (Macmillan, 1994); Back to Reality? Social Experience and Cultural Studies (Manchester University Press, 1997); British Fashion Design (1998), In the Culture Society. Art, Fashion and Popular Music (Routledge, 1999) y compiló junto a Paul Gilroy y Lawrence Grossberg, Without Guarantees. In Honour of Stuart Hall (Verso, 2000), con motivo del retiro de éste de la Open University en 1997.

Una aproximación paisajística de Potrerillos

Se está creando un nuevo espacio. La construcción de la presa de Potrerillos implica muchos cambios en la localidad. Potrerillos le debe su identidad a la importancia que tiene su esencia, su origen, y su historia en la conformación de su estructura y sus propiedades formales particulares, elementos que deben considerarse a la hora de analizar la definición de su paisaje. Es importante que el ordenamiento territorial y un análisis apropiado del paisaje guarden relación. Que formen parte de la misma estrategia de desarrollo, en función de la valoración de los sitios no sólo a partir de su funcionalidad sino a través de su configuración paisajística. Se garantiza de esta forma un tipo de intervención que no solo contemple el óptimo funcionamiento de la localidad sino que mantenga y potencie sus características diferenciadoras, que son en definitiva el motivo por el cual se plantea el desarrollo y transformación del sitio.

Estrategias para la reinserción social de jóvenes en conflicto con la ley

La justicia penal adolescente es un sistema de administración judicial que extiende los derechos y garantías del debido proceso a los adolescentes a quienes se acuse de haber participado en la comisión de una infracción a la ley penal. Se podría decir que las finalidades de la justicia penal juvenil, por orden de importancia son: Administrar justicia de forma democrática. Fomentando la responsabilización del adolescente que ha cometido una infracción penal; promoviendo su integración social y favoreciendo la participación de la comunidad en el proceso de reinserción social, mediante la oferta de servicios y programas para el cumplimiento de medidas socio-educativas. Cabe preguntarse ¿Las instituciones correccionales son coadyuvantes en la reinserción de los jóvenes en conflicto con la ley de tal modo que no vuelvan a confrontar con el orden jurídico vigente cuando egresen? La respuesta es muy compleja porque si bien desde la situación de las instituciones el aislamiento que sufre el joven no les da defensas para poder cambiar sus circunstancias de vida a la hora de reingresar a la sociedad y esto lleva a una alta probabilidad de volver a delinquir. Sin embargo las Ciencias Sociales plantean otras alternativa para logran la inserción de los jóvenes, una de ellas, se inclina a la estimulación de la resiliencia. Esta implica: sobreponerse a las dificultades y tener éxito a pesar de estar expuestos a situaciones de alto riesgo; mantener la competencia bajo presión, esto significa adaptarse con éxito y recuperarse de un trauma ajustándose de forma exitosa a los acontecimientos negativos de la vida.

Liberdade - ponto de chegada de uma criação contínua : os portuguez (1814-1826)

Razão de uma escolha: a importância do periódico O Portuguez e do seu redactor João Bernardo da Rocha Loureiro no desencadear da Revolução Liberal portuguesa de 1820, que deu início ao processo que colocou fim à monarquia absoluta e desencadeou a desconstrução do Antigo Regime em Portugal. Nesta panorâmica, e tendo como horizonte de chegada a fruição da liberdade, pode dizer-se que, enquanto sistema de significações colectivas, o imaginário do redactor Rocha Loureiro parece actuar como reacção ao poder dissolvedor da inteligência, como regulador que satisfaz a busca apaixonada de um grupo ou sociedade que persegue a sua identidade da qual a liberdade é elemento constituinte, fundamental e fundamentador. A liberdade define-se pela ausência de limitação às garantias necessárias para o harmonioso desenvolvimento do indivíduo. Antes de mais a liberdade é, na sua essência, uma ausência de limitação, sendo simultaneamente uma determinação positiva e espontânea da vontade de liberdade em que cada um procura atingir o fim racional de que está possuído. O indivíduo deseja a liberdade com vista a alcançar o melhor possível do seu ser. Na essência, a vontade de liberdade de cada um confunde-se com a vontade colectiva que encontra a sua expressão no poder político.

Procedimientos servianos de lectura acerca de los certámenes fúnebres en Eneida V : La naumaquia (vv. 104-285)

La figura de Servio y su comentario a la obra virgiliana constituye la summa opera de la tradición escolar tardoantigua; su importancia reside porque es el resultado de numerosas estratificaciones que recogen diversos abordajes exegéticos. Al tratarse de un comentario ?continuo?, los Commentarii servianos comprenden un conjunto de saberes que examinan la obra literaria desde la perspectiva histórica y de todo aquello que se relacionaba con esta. A partir de esta mirada lectora, la comunicación se centrará en el análisis que Servio realiza sobre la naumaquia del libro V de la Eneida (vv. 104-285), donde el texto base expone una secuencia narrativa caracterizada por epicismos homéricos y pos-homéricos que el gramático desarticula, privilegiando aspectos como el lingüístico, retórico, fabuloso y histórico-arqueológico. Asimismo, se comprobará que el certamen virgiliano constituye un pretexto para instalar un nuevo contexto que garantice la continuidad del sistema burocrático imperial

La formación del mercado de tierras durante la expansión de la frontera bonaerense. Chascomús y Junín, 1860-1890

En este trabajo nos proponemos analizar la formación del mercado de tierras durante la expansión de la frontera de la provincia de Buenos Aires entre 1860 y 1890, a partir de un enfoque local comparado, enfocando la investigación en dos partidos: Chascomús y Junín. Postulamos que la constitución del mercado de tierras en la campaña bonaerense fue un proceso gradual, que se inició apenas comenzaron a poblarse las tierras defendidas por los fuertes de la frontera interior y se establecían ciertas garantías de seguridad para la propiedad privada

La periferia de "la gran transformación" : El mercado de tierras en la provincia de Buenos Aires. Los casos de Chascomús y Junín en perspectiva comparada, 1780-1912

En este trabajo nos proponemos analizar la formación del mercado de tierras durante la expansión de la frontera de la provincia de Buenos Aires a partir de un enfoque local comparado, estudiando los partidos de Chascomús y Junín. Postulamos que la constitución del mercado de tierras en la campaña bonaerense fue un proceso gradual, que se inició apenas comenzaron a poblarse las tierras defendidas por los fuertes de la frontera interior y se establecieron ciertas garantías de seguridad para la propiedad privada.