Modelling the Transition from Homogeneous to Columnar States in Locust Hopper Bands

Many biological systems form structured swarms, for instance in locusts, whose swarms are known as hopper bands. There is growing interest in applying mathematical models to understand the emergence and dynamics of these biological and social systems. We model the locusts of a hopper band as point particles interacting through repulsive and attractive social forces on a one dimensional periodic domain. The primary goal of this work is to modify this well studied modelling framework to be more biological by restricting repulsion to act locally between near neighbors, while attraction acts globally between all individuals. This is a biologically motivated assumption because repulsion in swarms is mainly a collision avoidance mechanism. We construct a discrete and continuum model in the limit of infinite individuals. Using an energy formulation of both discrete and continuum models, we find energy minimizing equilibrium configurations that are either constant density or clumped. Then, we perform a stability analysis of these swarm configurations to find transitions of stability and hysteresis. We show that with local repulsion and global attraction the constant density equilibrium has a bifurcation to instability for both the total mass of the swarm and the attraction strength of individuals

Transfer Learning for Improving Model Predictions in Highly Configurable Software

Modern software systems are built to be used in dynamic environments using configuration capabilities to adapt to changes and external uncertainties. In a self-adaptation context, we are often interested in reasoning about the performance of the systems under different configurations. Usually, we learn a black-box model based on real measurements to predict the performance of the system given a specific configuration. However, as modern systems become more complex, there are many configuration parameters that may interact and we end up learning an exponentially large configuration space. Naturally, this does not scale when relying on real measurements in the actual changing environment. We propose a different solution: Instead of taking the measurements from the real system, we learn the model using samples from other sources, such as simulators that approximate performance of the real system at low cost. We define a cost model that transform the traditional view of model learning into a multi-objective problem that not only takes into account model accuracy but also measurements effort as well. We evaluate our cost-aware transfer learning solution using real-world configurable software including (i) a robotic system, (ii) 3 different stream processing applications, and (iii) a NoSQL database system. The experimental results demonstrate that our approach can achieve (a) a high prediction accuracy, as well as (b) a high model reliability.Comment: To be published in the proceedings of the 12th International Symposium on Software Engineering for Adaptive and Self-Managing Systems (SEAMS'17

Preschool ministries and churches that house them : a study to develop best practices to promote healthy collaborative relationships

https://place.asburyseminary.edu/ecommonsatsdissertations/2438/thumbnail.jp

Cervical Remodeling/ripening At Term And Preterm Delivery: The Same Mechanism Initiated By Different Mediators And Different Effector Cells

Premature cervical remodeling/ripening is believed to contribute to preterm delivery (PTD), the leading cause of perinatal morbidity and mortality. Despite considerable research, the causes of term and PTD remain unclear, and there is no effective treatment for PTD. We tested the hypothesis that complement activation plays a role in cervical remodeling and PTD. We studied cervical remodeling at term. We studied two mouse models of inflammation-induced PTD. The first model was induced by vaginal administration of lipopolysaccharide (LPS)and the second one by administration of progesterone antagonist RU486. Increased cervical C3 deposition and macrophage infiltration and increased serum C3adesArg and C5adesArg levels were observed in both models when compared to gestational age matched controls. A significant increase in collagen degradation, matrix metalloproteinase 9 (MMP-9) activity and tissue distensibility was observed in the cervix in both models. Mice deficient in complement receptor C5a did not show increased MMP-9 activity and cervical remodeling and did not deliver preterm in response to LPS or RU486, suggesting a role for C5aR in the cervical changes that precede PTD. In vitro studies show that macrophages release MMP-9 in response to C5a. Progesterone diminished the amount of C5aR on the macrophages surface, inhibited the release of MMP-9 and prevented PTD. In addition, macrophage depletion also prevented cervical remodeling and PTD in LPS-treated mice. We found that complement activation is not required for the physiological process that leads to term delivery in mice. Neither increased C3 cervical deposition nor increased C3a and C5a serum levels were observed at term. In addition, macrophages infiltration was found in PTD in contrast to term delivery were no leukocytes were found. Despite the different role of complement and different cellular effector cells, PTD and term delivery share a common dowsntream pathway characterized by increased metalloproteinases (MMPs) release and increased collagen degradation. However, different sources of MMPs were identified. Macrophages are the source of MMPs in PTD while cervical fibroblasts and columnar epithelial cells synthesize MMPs at term delivery. A dramatic diminution in serum progesterone levels precedes parturition at term but not in PTD, suggesting that progesterone withdrawal initiates cervical remodeling at term. On the other hand, MMPs release in PTD is triggered by C5a. Complement inhibition and supplementation with progesterone may be good therapeutic options to prevent this serious pregnancy complication. Preterm and term cervical remodeling occur through the same mechanism but they are initiated by different mediators and effector cells. That complement activation is required for PTD but not for the physiological process that leads to term delivery, suggests that complement is a potential specific biomarker and selective target to prevent PTD and thus avert neonatal mortality and morbidity

Is liquidity associate to profitabilitry? An analysis of the retail industry in Portugal

This Work Project analyses the relationship betweenliquidity, proxied by Cash Conversion Cycle and Liquidity Ratios,and Return on Assets, namely how and to what extent these variables associate.Based on a sample of Portuguese retail companies forthe period 2016-2018,the results show thatDays Payable Outstanding and Days Sales Outstanding havea significant influence in profitabilitywhereasDays Inventory Outstanding doesnot. Moreover, liquidity profiles and sources of profitability differ between smallerand biggercompanies.The research is relevant to working capital management and addresses to managers whocan improve profitabilityby reducing liquidity

Development of Multiple Input Single Output DC-DC Converter

This senior project report details the testing and validation of the designed DC-DC Multiple Input Single Output converter. The MISO uses four-switch buck-boost topology to output a single 48V from multiple nominal 24V inputs. The previous iteration of the MISO was plagued with an overheating mosfet that would drastically reduce the lifespan of the boards and reduce efficiency. This newest iteration includes more ground panes to combat the issues. In addition, the 200W MISO board was redesigned to utilize an edge connector for secure installment, removal, and replacement in the actual DC House system panel. The slots also have a locking mechanism for the MISOs to ensure a secure connection. Also, an LED was added to the board to indicate when the board is in operation. Results of hardware measurements on the 200W and 400W MISO converters show that the efficiency of full load is above 97.8%, line regulation of 2.5% to 5.65%, load regulation of 0.62% to 4.09% and output voltage ripple of 1.29% to 2.82%

Teamwork in primary care: perspectives of general practitioners and community nurses in Lithuania.

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A Guarda Nacional Republicana na Prevenção do Terrorismo: Troca e Recolha de Informações entre Forças Policiais Europeias

Atualmente a Europa enfrenta um conjunto de ameaças que apesar de não serem recentes têm sofrido algumas mutações ao longo do tempo. O terrorismo é um fenómeno que se enquadra nas ameaças que têm vindo a afetar de forma severa o funcionamento da sociedade europeia, não devido apenas ao número de atentados, mas devido à forma como estes têm sido perpetrados, assim como o foco mediático que sobre eles incide. Como tal surge a necessidade de criar medidas robustas que permitam realizar ações de prevenção, devendo estas passar pelo fortalecimento da cooperação, essencialmente no intercâmbio de informações entre forças e agências dos diferentes Estados-Membros. Desta forma, surge o presente trabalho de investigação, com o objetivo de analisar o papel da GNR como força de segurança de um Estado-Membro da UE, como ator na recolha e intercâmbio de informações que permitam contribuir para a prevenção do terrorismo. Quanto à metodologia utilizada na investigação foi dado privilégio a uma abordagem qualitativa, assente na análise documental e na realização de entrevistas semidiretivas, permitindo-nos assim alcançar as conclusões da investigação. No fim desta investigação confirmamos que a GNR desempenha de facto um papel ativo na prevenção do terrorismo através da recolha e do intercâmbio de informações com outras agências policiais na Europa e em Portugal. Verificamos que, quanto à recolha de informações, a GNR desempenha um papel importante decorrente essencialmente da cobertura territorial da sua atividade e do efetivo populacional que tem sob a sua responsabilidade. No que concerne ao intercâmbio de informações, este papel manifesta-se essencialmente através das estruturas que a Guarda integra que têm como função estabelecer o intercâmbio de informações e a cooperação policial em território nacional e europeu. Por último apuramos que ainda existem vários obstáculos que impedem que os processos de intercâmbio de informações tenham os resultados pretendidos, dificultando o papel da GNR na prevenção de ameaças desta natureza, obstáculos estes que envolvem desde limitações ao nível legislativo até à própria resistência em fornecer informações por parte dos diferentes atores que contribuem para a recolha e intercâmbio de informações de cariz terrorista