The role of Ken&Barbie in JAK/STAT signalling during development of Drosophila melanogaster

Cell-cell interactions during embryonic development are crucial in the co-ordination of growth, differentiation and maintenance of many different cell types. To achieve this co-ordination each cell must properly translate signals received from neighbouring cells, into spatially and temporally appropriate developmental responses. A surprisingly limited number of signal pathways are responsible for the differentiation of enormous variety of cell types. As a result, pathways are frequently 'reused' during development. Thus, in mammals the JAK/STAT pathway is required during early embryogenesis, mammary gland formation, hematopoiesis and, finally, plays a pivotal role in immune response. In the canonical way, the JAK/STAT pathway is represented by a transmembrane receptor associated with a Janus kinase (JAK), which upon stimulation by an extra-cellular ligand, phosphorylates itself, the receptor and, finally, the signal transducer and activator of transcription (STAT) molecules. Phosphorylated STATs dimerise and translocate to the nucleus where they activate transcription of target genes. The JAK/STAT pathway has been conserved throughout evolution, and all known components are present in the genome of Drosophila melanogaster. Besides hematopoietic and immunity functions, the pathway is also required during development for processes including embryonic segmentation, tracheal morphogenesis, posterior spiracle formation etc. This study describes Drosophila Ken&Barbie (Ken) as a selective regulator of JAK/STAT signalling. ken mutations identified in a screen for modulators of an eye overgrowth phenotype, caused by over-expression of the pathway ligand unpaired, also interact genetically with the pathway receptor domeless (dome) and the transcription factor stat92E. Over-expression of Ken can phenocopy developmental defects known to be caused by the loss of JAK/STAT signalling. These genetic interactions suggest that Ken may function as a negative regulator of the pathway. Ken has C-terminal Zn-finger domain, presumably for DNA binding, and N-terminal BTB/POZ domain, often found in transcriptional repressors. Using EGFP-fused construct expressed in vivo revealed nuclear accumulation of Ken. Therefore, it is proposed that Ken may act as a suppresser of STAT92E target genes. An in vitro assay, termed SELEX, determined that Ken specifically binds to a DNA sequence, with the essential for DNA recognition core overlapping that of STAT92E. This interesting observation suggests that not all STAT92E sites may also allow Ken binding. Strikingly, when effects of ectopic Ken on the expression of putative JAK/STAT pathway target genes were examined, only a subset of the genes tested, namely vvl, trh and kni, were down-regulated by Ken, whereas some others, such as eve and fj, appeared to be unresponsive. Further analysis of vvl, one of the genes susceptible to ectopic Ken, was undertaken. In the developing hindgut, expression of vvl is JAK/STAT pathway dependent, but remains repressed in the posterior spiracles, despite the stimulation of STAT92E by Upd in their primordia. Importantly, ken is also expressed in the developing posterior spiracles. Strikingly, up-regulation of vvl is observed in these tissues in ken mutant embryos. These imply that while ectopic Ken is sufficient to repress the expression of vvl in the hindgut, endogenous Ken is also necessary to prevent its activation in the posterior spiracles. It is therefore conceivable that ectopic vvl expression in the posterior spiracles of the ken mutants may be the result of de-repression of endogenous STAT92E activity. Another consequence of these observations is a fine balance that must exist between STAT92E and Ken activities. Apparently, endogenous level of Ken is sufficient to repress vvl, but not other, as yet unidentified, JAK/STAT pathway targets, whose presumable activation by STAT92E is required for posterior spiracle development as the embryos mutant for dome, the receptor of the pathway, show severe spiracle defects. These defects are also observed in the embryos mis-expressing Ken. Though it is possible that the posterior spiracle phenotype caused by higher levels of Ken results from a JAK/STAT pathway independent activity, it seems to be more likely that Ken acts in a dosage dependent manner, and extra Ken is able to further antagonise JAK/STAT pathway target genes. While STAT92E binding sites required for target gene expression have been poorly characterised, the existence of genome data allows the prediction of candidate STAT92E sites present in target genes promoters to be attempted. When a 6kb region containing the putative regulatory domains flanking the vvl locus are examined, only a single potential STAT92E binding site located 825bp upstream of the translational start can be detected. Strikingly, this site also includes a perfect Ken binding sequence. Such an in silico observation, though consistent with both Ken DNA binding assay in vitro and regulation of STAT92E target genes in vivo, however, requires further analysis. The JAK/STAT pathway is implicated in a variety of processes during embryonic and larval development as well as in imago. In each case, stimulation of the same transcription factor results in different developmental outcomes. While many potential mechanisms have been proposed and demonstrated to explain such pleiotropy, the present study indicates that Ken may represent another mechanism, with which signal transduction pathways are controlled. Ken selectively down-regulates a subset of potential target genes and so modifies the transcriptional profile generated by activated STAT92E - a mechanism, which may be partially responsible for differences in the morphogenetic processes elicited by JAK/STAT signalling during development.

Domestic policy responses to the food price crisis: The case of Bolivia

In face of the global food crisis of 2007-2008, severe concerns arose about how developing countries would be affected by the extreme short-term fluctuations in international commodity prices. We examine the effects of the crisis on Bolivia, one of the poorest countries of the Americas. We focus on the effectiveness of the domestic policy interventions in preventing spillovers of the development of international food prices to domestic markets. Using a cointegration model, we study price interdependencies of wheat flour, sunflower oil and poultry. The analysis suggests that the policy measures taken had little effect on food security during the food crisis. Throughout the entire period, perfect price transmission between the Bolivian poultry and sunflower oil markets and the respective international reference markets existed. Bolivian prices were determined by international prices and the policy interventions in the markets of these two commodities were not found to have had an effect. The government's large-scale wheat flour imports did not shield Bolivian consumers from the shocks of international prices.

Core Labor Rights

The working paper’s main objective is to explore the extent to which non-compliance to international labor rights is caused by global competition. From the perspective of institutional economics, compliance with core labor rights is beneficial for sustainable development. Nonetheless, violations of these rights occur on a massive scale. The violators usually blame competitive pressures. A number of studies have come to the conclusion that non-compliance does not provide for a competitive edge, thereby denying any economic rationale for non-compliance. While we sympathize with this conclusion, we find that these studies suffer from faulty assumptions in the design of their regression analyses. The assumption of perfect markets devoid of power relations is particularly unrealistic. While workers' rights promise long-term benefits, they may incur short-term production cost increases. On the supply side, the production sites with the highest amount of labor rights violations are characterized by a near perfect competitive situation. The demand side, however, is dominated by an oligopoly of brand name companies and large retailers. Facing a large pool of suppliers, these companies enjoy more bargaining power. Developing countries, the hosts to most of these suppliers, are therefore limited in their ability to raise labor standards on their own. This competitive situation, however, is the very reason why labor rights have to be negotiated internationally. Our exploration starts with an outline of the institutionalist argument of the benefits of core labor rights. Second, we briefly examine some cross-country empirical studies on the impact of trade liberalization (as a proxy for competitive pressures). Third, we develop our own argument which differentiates the impact of trade liberalization along the axes of labor- and capital-intensive production as well as low and medium skill production. Finally, we present evidence from a study on the impact of trade liberalization in Indonesia on the garment industry as an example of a low skill, laborintensive industry on the one hand, and the automobile as an example for a medium skill, capital-intensive industry on the other hand. Because the garment industry’s workforce consists mainly of women, we also discuss the gender dimension of trade liberalization.

Optimizing Robust Quantum Gates in Open Quantum Systems

We are currently at the cusp of a revolution in quantum technology that relies not just on the passive use of quantum effects, but on their active control. At the forefront of this revolution is the implementation of a quantum computer. Encoding information in quantum states as “qubits” allows to use entanglement and quantum superposition to perform calculations that are infeasible on classical computers. The fundamental challenge in the realization of quantum computers is to avoid decoherence – the loss of quantum properties – due to unwanted interaction with the environment. This thesis addresses the problem of implementing entangling two-qubit quantum gates that are robust with respect to both decoherence and classical noise. It covers three aspects: the use of efficient numerical tools for the simulation and optimal control of open and closed quantum systems, the role of advanced optimization functionals in facilitating robustness, and the application of these techniques to two of the leading implementations of quantum computation, trapped atoms and superconducting circuits. After a review of the theoretical and numerical foundations, the central part of the thesis starts with the idea of using ensemble optimization to achieve robustness with respect to both classical fluctuations in the system parameters, and decoherence. For the example of a controlled phasegate implemented with trapped Rydberg atoms, this approach is demonstrated to yield a gate that is at least one order of magnitude more robust than the best known analytic scheme. Moreover this robustness is maintained even for gate durations significantly shorter than those obtained in the analytic scheme. Superconducting circuits are a particularly promising architecture for the implementation of a quantum computer. Their flexibility is demonstrated by performing optimizations for both diagonal and non-diagonal quantum gates. In order to achieve robustness with respect to decoherence, it is essential to implement quantum gates in the shortest possible amount of time. This may be facilitated by using an optimization functional that targets an arbitrary perfect entangler, based on a geometric theory of two-qubit gates. For the example of superconducting qubits, it is shown that this approach leads to significantly shorter gate durations, higher fidelities, and faster convergence than the optimization towards specific two-qubit gates. Performing optimization in Liouville space in order to properly take into account decoherence poses significant numerical challenges, as the dimension scales quadratically compared to Hilbert space. However, it can be shown that for a unitary target, the optimization only requires propagation of at most three states, instead of a full basis of Liouville space. Both for the example of trapped Rydberg atoms, and for superconducting qubits, the successful optimization of quantum gates is demonstrated, at a significantly reduced numerical cost than was previously thought possible. Together, the results of this thesis point towards a comprehensive framework for the optimization of robust quantum gates, paving the way for the future realization of quantum computers.

Optical Antennas for Biosensing Applications

The aim of the thesis is to theoretically investigate optical/plasmonic antennas for biosensing applications. The full 3-D numerical electromagnetic simulations have been performed by using finite integration technique (FIT). The electromagnetic properties of surface plasmon polaritons (SPPs) and the localized surface plasmons (LSPs) based devices are studied for sensing purpose. The surface plasmon resonance (SPR) biosensors offer high refractive index sensitivity at a fixed wavelength but are not enough for the detection of low concentrations of molecules. It has been demonstrated that the sensitivity of SPR sensors can be increased by employing the transverse magneto-optic Kerr effect (TMOKE) in combination with SPPs. The sensor based on the phenomena of TMOKE and SPPs are known as magneto-optic SPR (MOSPR) sensors. The optimized MOSPR sensor is analyzed which provides 8 times higher sensitivity than the SPR sensor, which will be able to detect lower concentration of molecules. But, the range of the refractive index detection is limited, due to the rapid decay of the amplitude of the MOSPR-signal with the increase of the refractive indices. Whereas, LSPs based sensors can detect lower concentrations of molecules, but their sensitivity is small at a fixed wavelength. Therefore, another device configuration known as perfect plasmonic absorber (PPA) is investigated which is based on the phenomena of metal-insulator-metal (MIM) waveguide. The PPA consists of a periodic array of gold nanoparticles and a thick gold film separated by a dielectric spacer. The electromagnetic modes of the PPA system are analyzed for sensing purpose. The second order mode of the PPA at a fixed wavelength has been proposed for the first time for biosensing applications. The PPA based sensor combines the properties of the LSPR sensor and the SPR sensor, for example, it illustrates increment in sensitivity of the LSPR sensor comparable to the SPR and can detect lower concentration of molecules due to the presence of nanoparticles.

Microsatellites from Fosterella christophii (Bromeliaceae) by de novo transcriptome sequencing on the Pacific Biosciences RS platform

• Premise of the study: Microsatellite markers were developed in Fosterella christophii (Bromeliaceae) to investigate the genetic diversity and population structure within the F. micrantha group, comprising F. christophii, F. micrantha, and F. villosula. • Methods and Results: Full-length cDNAs were isolated from F. christophii and sequenced on a Pacific Biosciences RS platform. A total of 1590 high-quality consensus isoforms were assembled into 971 unigenes containing 421 perfect microsatellites. Thirty primer sets were designed, of which 13 revealed a high level of polymorphism in three populations of F. christophii, with four to nine alleles per locus. Each of these 13 loci cross-amplified in the closely related species F. micrantha and F. villosula, with one to six and one to 11 alleles per locus, respectively. • Conclusions: The new markers are promising tools to study the population genetics of F. christophii and to discover species boundaries within the F. micrantha group.

Taming Chaotic Circuits

Control algorithms that exploit chaotic behavior can vastly improve the performance of many practical and useful systems. The program Perfect Moment is built around a collection of such techniques. It autonomously explores a dynamical system's behavior, using rules embodying theorems and definitions from nonlinear dynamics to zero in on interesting and useful parameter ranges and state-space regions. It then constructs a reference trajectory based on that information and causes the system to follow it. This program and its results are illustrated with several examples, among them the phase-locked loop, where sections of chaotic attractors are used to increase the capture range of the circuit.

On the Fabrication of Microparticles Using Electrohydrodynamic Atomization Method

A new approach for the control of the size of particles fabricated using the Electrohydrodynamic Atomization (EHDA) method is being developed. In short, the EHDA process produces solution droplets in a controlled manner, and as the solvent evaporates from the surface of the droplets, polymeric particles are formed. By varying the voltage applied, the size of the droplets can be changed, and consequently, the size of the particles can also be controlled. By using both a nozzle electrode and a ring electrode placed axisymmetrically and slightly above the nozzle electrode, we are able to produce a Single Taylor Cone Single Jet for a wide range of voltages, contrary to just using a single nozzle electrode where the range of permissible voltage for the creation of the Single Taylor Cone Single Jet is usually very small. Phase Doppler Particle Analyzer (PDPA) test results have shown that the droplet size increases with increasing voltage applied. This trend is predicted by the electrohydrodynamic theory of the Single Taylor Cone Single Jet based on a perfect dielectric fluid model. Particles fabricated using different voltages do not show much change in the particles size, and this may be attributed to the solvent evaporation process. Nevertheless, these preliminary results do show that this method has the potential of providing us with a way of fine controlling the particles size using relatively simple method with trends predictable by existing theories.

El Discurso de Hamás como elemento perpetuador del conflicto Israel-Palestina a partir de la Segunda Intifada

El conflicto árabe-israelí es de los más antiguos que existen en el mundo, es por esto que es importante conocer algunas de las causalidades del por qué este conflicto no ha logrado solucionarse. En este caso se estudiará como el discurso de Hamás logra influir en la prolongación de este conflicto. Para determinar como el discurso logra influir se hace la división en tres capítulos. En el primer capitulo se determinan cuales son los elementos característicos de su discurso; en este caso los elementos son antisemitismo, irredentismo y nacionalismo que se encuentran presentes en todos los discursos y en su carta fundacional. En una segunda parte se busca determinar como el discurso se convierte en realidad, haciéndose tangible por medio de atentados terroristas por parte del brazo armado de Hamás denominado Ezzedine Al-Qassam. En el último capítulo se determina como el discurso se convierte en un elemento determinante para la prolongación del conflicto y de que manera afecta tanto a la población israelí como a la palestina. Por otra parte se busca evidenciar como el discurso de Hamás influye en diferentes niveles (individual, comunitario, binacional e internacional). Finalmente se logra establecer como el discurso de Hamás y las experiencias de vida de israelíes y palestinos configuran el escenario perfecto para la continuación del conflicto.

Innovación y liderazgo como ejes de éxito en la Compañía Colombia

A través de este trabajo, se define el liderazgo como la capacidad de obtener seguidores y la innovación como el proceso mediante el cual se obtiene cambios sustanciales generando gran impacto en el reconocimiento en los clientes. El líder debe enfocar los esfuerzos de las personas en dirección de objetivo común, generando sinergia e identificando y potencialización las habilidades de cada uno de los miembros del equipo en pro de las metas del equipo. La innovación, es fundamental para las empresas que desean un lugar importante en la mente de los consumidores, el nivel de recordación que estos tengan, de la empresa o el producto/servicio que esta venda, es el medidor principal del éxito de una organización. El éxito en la combinación entre la innovación y el liderazgo, garantiza el verdadero éxito de la organización. En este documento se encuentra la razón por la cual La Compañía Colombia ha basado su éxito en la perfecta armonía de estas dos variables, logrando un reconocimiento rotundo y arrollador en el mundo, como una compañía de tecnología diversificada capaz de revolucionar y generar cambios radicales enfocando siempre sus esfuerzos en el éxito de sus clientes.

Exercise sheet 8

Exercises and solutions in LaTex

The effect of Ponzi schemes on crime: Evidence from the colombian case

This paper estimates the impact of a massive negative income shock led by the simultaneous crash down of several Ponzi schemes (also known as financial ``pyramids"") in Colombia on crime rates at the municipal level. Using novel data on the spatial incidence of the latest wave of Colombian pyramids and their crash down date, I estimate difference-in-differences models with both monthly and yearly frequency. I find that the negative income shock of the pyramids" crash down differentially exacerbates crime in affected municipalities compared to those with no presence of Ponzi schemes. This is true for minor offenses like commercial theft or residential burglary, but not for major crimes as murder or terrorism.

Exercise sheet 8 pdf

Exercises and solutions in PDF

Es la teoría microeconómica tradicional acertada a la hora de entender y/o explicar el comportamiento del consumidor y, por ende del mercado, a comparación del neuromarketing

A medida que pasa el tiempo; la ciencia, el desarrollo tecnológico y la constante búsqueda de encontrar nuevas verdades, más fehacientes y que logren responder más asertivamente los diferentes cuestionamientos de la humanidad, han logrado redefinir las teorías y los axiomas que, en su momento, se tomaron como el dogma a seguir en diferentes disciplinas y cuestionamientos de la sociedad y la industria. La concepción tradicional que se tiene de la mente y el comportamiento del consumidor tenía vacios importantes en términos de aplicabilidad y generalización de sus teorías, pues pensar que la humanidad desarrolla sus decisiones de compra bajo análisis netamente racionales y apegados a estructuras temporales para manejar su dinero es un supuesto que no se emplea de manera general y concienzuda por el común. Antes que agentes 100% racionales, con un completo flujo de información y en un mercado perfecto bajo todos los preceptos económicos, somos personas de sentimientos y sentidos. Reaccionamos ante situaciones, estados de ánimo y estímulos, donde es nuestro cerebro quien recibe todo el contexto cognitivo que nos brinda el entorno y entonces actúa (y compra) de diferentes maneras. Es allí donde el Neuromarketing nace como un claro ejemplo de esa búsqueda por una nueva verdad. Una donde entender al consumidor no deje de lado su faceta más real; sus reacciones, pues son estas las que realmente definen qué le gusta o no y qué despierta en él un impulso lo suficientemente importante como para incidir en su decisión de compra. Es por ello que el Neuromarketing se ha adentrado a estudiar lo más profundo y verídico del consumidor, su cerebro. Alejándose de las técnicas tradicionales de investigación de mercados, donde el consumidor puede desvirtuar la información que percibe de un producto o una campaña publicitaría por diferentes razones sociales y psicológicas. El Neuromarketing se ha adentrado al estudio del consumidor y su cerebro mediante técnicas biométricas, en las cuales expone al consumidor al marketing y analiza sus reacciones cerebrales en términos de interés, adrenalina, memoria activa y sentimientos, apoyado por técnicas como el ¨eye tracking¨, donde las interacciones visuales del consumidor permiten identificar los puntos calientes y de interés en determinada pieza publicitaria. Pero el estudio, entendido por algunos como ¨invasivo¨ frente a las libertades en términos de privacidad y libertad de elección del consumidor deben ser responsablemente dirigidos y puestos bajo un contexto científico, donde el único fin sea el de generar nuevas hipótesis y teorías que permitan tener un mejor conocimiento del comportamiento del consumidor sin traspasar los límites del control del mismo. El Neuromarketing debate su existencia misma entre la creación de nuevas metodologías de acercamiento al pensamiento del consumidor, la efectividad de sus conocimiento dados a la industria y el yugo social que acarrea esta ciencia debido a la potencial coerción a los consumidores debido a sus hallazgos.

Alteración de la atención y concentración en estudiantes de medicina que realizan turnos de noche

El sueño, es indispensable para la recuperación, física, mental y de procesos como la consolidación de memoria, atención y lenguaje. La privación de sueño (PS) incide en la atención y concentración. La PS es inherente a la formación médica, pero no es claro el papel de los turnos nocturnos en estudiantes, porque no cumplen con un objetivo académico, pero hay relación con disminución de la salud, productividad, accidentes, y alteraciones en diversas actividades. Está descrito el impacto de la PS sobre la capacidad de aprendizaje y aspectos como el ánimo y las relaciones interpersonales. MÉTODOS: Se realizó un estudio analítico observacional de cohorte longitudinal, con tres etapas de medición a 180 estudiantes de Medicina de la Universidad del Rosario, que evaluó atención selectiva y concentración mediante la aplicación de la prueba d2, validada internacionalmente para tal fin. RESULTADOS: Se estudiaron 180 estudiantes, 115 mujeres, 65 hombres, entre los 18 y 26 años (promedio 21). Al inicio del estudio dormían en promedio 7,9 horas, cifra que se redujo a 5,8 y 6,3 en la segunda y tercera etapa respectivamente. El promedio de horas de sueño nocturno, disminuyó en el segundo y tercer momento (p<0,001); Además se encontró mediante la aplicación de la prueba d2, que hubo correlación significativa directa débil, entre el promedio de horas de sueño, y el promedio del desempeño en la prueba (r=0.168, p=0.029) CONCLUSIONES: La PS, con períodos de sueño menores a 7,2 horas, impactan de manera importante la atención selectiva, la concentración