Influence of proton bunch parameters on a proton-driven plasma wakefield acceleration experiment

We use particle-in-cell (PIC) simulations to study the effects of variations of the incoming 400 GeV proton bunch parameters on the amplitude and phase of the wakefields resulting from a seeded self-modulation (SSM) process. We find that these effects are largest during the growth of the SSM, i.e. over the first five to six meters of plasma with an electron density of $7 \times10^{14}$ cm$^{-3}$. However, for variations of any single parameter by $\pm$5%, effects after the SSM saturation point are small. In particular, the phase variations correspond to much less than a quarter wakefield period, making deterministic injection of electrons (or positrons) into the accelerating and focusing phase of the wakefields in principle possible. We use the wakefields from the simulations and a simple test electron model to estimate the same effects on the maximum final energies of electrons injected along the plasma, which are found to be below the initial variations of $\pm$5%. This analysis includes the dephasing of the electrons with respect to the wakefields that is expected during the growth of the SSM. Based on a PIC simulation, we also determine the injection position along the bunch and along the plasma leading to the largest energy gain. For the parameters taken here (ratio of peak beam density to plasma density $n_{b0}/n_0 \approx 0.003$), we find that the optimum position along the proton bunch is at $\xi \approx -1.5 \; \sigma_{zb}$, and that the optimal range for injection along the plasma (for a highest final energy of $\sim$1.6 GeV after 10 m) is 5-6 m.Comment: 9 pages, 12 figure

Therapeutic potential of the renin angiotensin system in ischaemic stroke

The renin angiotensin system (RAS) consists of the systemic hormone system, critically involved in regulation and homeostasis of normal physiological functions [i.e. blood pressure (BP), blood volume regulation], and an independent brain RAS, which is involved in the regulation of many functions such as memory, central control of BP and metabolic functions. In general terms, the RAS consists of two opposing axes; the ‘classical axis’ mediated primarily by Angiotensin II (Ang II), and the ‘alternative axis’ mediated mainly by Angiotensin-(1–7) (Ang-(1–7)). An imbalance of these two opposing axes is thought to exist between genders and is thought to contribute to the pathology of cardiovascular conditions such as hypertension, a stroke co-morbidity. Ischaemic stroke pathophysiology has been shown to be influenced by components of the RAS with specific RAS receptor antagonists and agonists improving outcome in experimental models of stroke. Manipulation of the two opposing axes following acute ischaemic stroke may provide an opportunity for protection of the neurovascular unit, particularly in the presence of pre-existing co-morbidities where the balance may be shifted. In the present review we will give an overview of the experimental stroke studies that have investigated pharmacological interventions of the RAS

Biodiversity and plant-pollinator interactions in native forest areas of Terceira Island (Azores)

Neste trabalho avaliámos o impacto que a perturbação humana das comunidades da floresta nativa da ilha Terceira (Açores) tem sobre a riqueza específica e nas interações ecológicas entre plantas e polinizadores. Para o efeito selecionámos dois locais emparelhados (um bem conservado e outro degradado), em duas áreas de estudo (Lomba e Pico Galhardo) e analisámos a integridade das redes ecológicas planta-polinizador. Constatámos que nas áreas bem conservadas as interações são dominadas por espécies nativas, enquanto que nas áreas perturbadas, apesar da prevalência de plantas introduzidas, os polinizadores nativos têm um papel relevante. Em cada área houve apenas uma planta que concentrou as visitas dos polinizadores, que na sua maioria pertenceram à ordem Diptera e tiveram hábitos generalistas; Biodiversity and plant-pollinator interactions in native forest areas of Terceira island (Azores) Abstract: In this work we evaluate the effect of anthropogenic disturbance in native forest communities of Terceira island (Azores) on species richness and on plant-pollinator ecological interactions. We selected paired sampling sites (one well-preserved and one disturbed) in two study areas (Lomba and Pico Galhardo) and we analysed plant-pollinator networks integrity. We found that native species dominate in well-preserved sites whereas in disturbed sites, despite the prevalence of introduced plants, native pollinators play an important role. In each area there was a plant that received most of the insect visits, being these mainly from Diptera order and having generalist behaviour

Tres casas de Luis Barragán

Las casas predominan en el legado arquitectónico del mexicano Luis Barragán. En estos proyectos imperan conceptos como serenidad, silencio, intimidad y asombro, que él consideraba ejercer un papel fundamental en la vivienda humana, y como afirmó1, nunca han dejado de ser el faro de sus búsquedas. Partiendo de la convención de que su obra se divide, como afirma Carlos Martí2, en tres etapas diferenciadas y con el interés de estudiar la tipología que predomina en la producción de Barragán, he escogido como objeto de estudio para este trabajo, tres casas, cada una de ellas representando uno de los momentos de la carrera del arquitecto. La primera, la Casa González Luna (1929), pertenece al grupo de casas de influencia árabe y andaluza que realiza durante su etapa temprana en Guadalajara; la segunda es la casa que proyecta para dos Familias en la avenida Parque de México (Ciudad de México, 1936- 37) en la cual adopta el lenguaje del racionalismo internacional; y finalmente, la última obra que logró concluir íntegramente, la Casa Gilardi (Ciudad de México, 1975-77), donde su experiencia arquitectónica alcanza una tensión máxima. El objetivo es, a través del análisis de dichas obras realizar un paralelo entre las tres etapas, identificando los rasgos arquitectónicos que han permanecido a través del tiempo y del cambio estilístico en la arquitectura de Barragán

Understanding how fear of flying affects the consumption behavior of commercial airline passengers

It is estimated that fear of flying affects more than one-third of all people and it is related to a high perception of risk. This fear affects people negatively on a personal and professional level. It also impacts airline costs because it reduces demand and might compromise flights' on-time performance among other disruptions. Most of the studies on perceptions and behaviors of consumers with this fear have specific contexts and are quantitative. Therefore, this research had a qualitative approach to understand how fear of flying affects the consumption behavior of commercial airline passengers. The triangulation method was applied by collecting 44 web testimonials from fear of flying passengers and by conducting semi-structured interviews, 11 with fear of flying passengers and 3 with clinical psychologists involved with the treatment of this fear. Following the content analysis of the collected data, the main result of this research is that the consumption behavior of fear of flying passengers is affected not just by their air travel perceived risks but also by how they cope with the stress associated with it. The outcome can be positive or negative for both, FoF passengers and airlines. It is recommended that airlines consider this target segment in their marketing strategy to potentialize the market dimension, starting by reinforcing the brand reputation and endorsing support for these consumers

The Vila Militar of Rio de Janeiro: the Genealogy of a Modern Design

This paper investigates the principles that guided the design of the Vila Militar of Rio de Janeiro, a military town built in 1908. It is a narrative about the urban and architectural features of the pioneering military town in Brazil. Fruit of a Brazilian Army modernization program of the early twentieth century, this village was planned as the first autonomous unit, consisting of bureaucratic and residential buildings, military schools and training areas, in order to serve as a model to other military town to be built throughout the country, according to Frank McCann (2007). Designed in accordance with modern principles of circulation, hygiene, large green areas, zoning, standardization and easy reproducibility of forms, the blueprints reflected the corporate hierarchy in space and on the houses’ architecture. It means that, each rank was settled in different areas and with different types of housing but also different typologies was designed for the same rank offering a rich architectural landscape. In addition to the institution´s modernization, this settlement had a pedagogic function in introducing new notions of space and habitability and, moreover, it had a symbolic role of representing the officer’s emergence in the sociopolitical context of the First Republic. The officer´s houses in the Vila Militar breaks with the previous types of military housing from the 19th century. Although it was not effectively reproduced in other places as firstly intended, the construction of the Vila Militar still ensures its significance as a pioneering military living in the 20th century and due to its role as one of the main establishments of the corporation in Brazil. It is part of a building type with a striking presence in Brazilian cities landscapes along the 20th century. Finally, this paper strives to contribute with one more chapter of the history of Brazilian´s military town and, consequently, Brazilian´s history of urban and housing planning

Fintech report: an overview of the Iberian fintech market

The FinTech industry is quite dynamic and it has progressed beyond its early stages rapidly. FinTech can be defined as “organizations that combine innovative business models and technology to enable, enhance and disrupt financial services” (Hwa, 2019). This Work Project aims to analyse Portuguese and Spanish FinTechs and combine the findings in a comprehensive report of the Iberian FinTech ecosystem. This paper explains how that report was built and it is organized in four main parts: literature review, methodology, results and personal reflection. Additionally, limitations and recommendations for further research are presented in the end of the paper

Public knowledge and perceptions on family foster care: contributes to the development of foster care in Portugal

info:eu-repo/semantics/publishedVersio

A CSR communication strategy for Ibersol: fighting hunger in Portugal

Field lab in marketingThe purpose of this Work Project is to develop a Corporate Social Responsibility Communication Strategy for the restaurant group Ibersol, more specifically for the brands Pizza Hut, Burger King, Pans & Company, KFC and Pasta Caffé. The proposed CSR Strategy includes Cause-Related Marketing, Corporate Fundraising and Employee Volunteering initiatives, which aim at fighting hunger in Portugal while enhancing the brand image of Ibersol as a group and of each brand individually. Secondary and primary researches were conducted to ensure the feasibility of the initiatives, and their ability to successfully meet the defined communication and fundraising goals