Environmental Policy, Spatial Spillovers and the Emergence of Economic Agglomerations

We explain the spatial concentration of economic activity, in a model of economic geography, when the cost of environmental policy - which is increasing in the concentration of emissions - and an immobile production factor act as centrifugal forces, while positive knowledge spillovers and iceberg transportation costs act as centripetal forces. We study the agglomeration effects caused by trade-offs between centripetal and centrifugal forces. The above effects govern firms’ location decisions and as a result, they define the distribution of economic activity across space. We derive the rational expectations equilibrium and the social optimum, compare the outcomes and characterize the optimal spatial policies.Agglomeration, Spatial Economics, Environmental Policy, Knowledge Spillovers, Transportation Cost

Goal-Driven Query Answering for Existential Rules with Equality

Inspired by the magic sets for Datalog, we present a novel goal-driven approach for answering queries over terminating existential rules with equality (aka TGDs and EGDs). Our technique improves the performance of query answering by pruning the consequences that are not relevant for the query. This is challenging in our setting because equalities can potentially affect all predicates in a dataset. We address this problem by combining the existing singularization technique with two new ingredients: an algorithm for identifying the rules relevant to a query and a new magic sets algorithm. We show empirically that our technique can significantly improve the performance of query answering, and that it can mean the difference between answering a query in a few seconds or not being able to process the query at all

Environmental Policy and the Collapse of the Monocentric City

We explain the spatial concentration of economic activity, in a model of economic geography, when the cost of environmental policy - which is increasing in the concentration of pollution - acts as a centrifugal force, while positive knowledge spillovers and a site with natural cost advantage act as centripetal forces. We study the agglomeration eects caused by trade-os between centripetal and centrifugal forces which eventually determine the distribution of economic activity across space. The rational expectations market equilibrium with spatially myopic environmental policy results either in a monocentric or in a polycentric city with the major cluster at the natural advantage site. The regulator�s optimum results in a bicentric city which suggests that when environmental policy is spatially optimal, the natural advantage sites do not act as attractors of economic activity.Agglomeration, Space, Environmental policy, Natural cost advantage, Knowledge spillovers, Monocentric-bicentric city

Environmental Policy, Spatial Spillovers and the Emergence of Economic Agglomerations

We explain the spatial concentration of economic activity, in a model of economic geography, when the cost of environmental policy - which is increasing in the concentration of pollution - and an immobile production factor act as centrifugal forces, while positive knowledge spillovers and iceberg transportation costs act as centripetal forces. We study the agglomeration eects caused by trade-os between centripetal and centrifugal forces. The above eects govern rms� location decisions and, as a result, they dene the distribution of economic activity across space. We derive the rational expectations equilibrium, which results either in a monocentric or in a polycentric city, and the regulator�s optimum, which results in a bicentric city. We compare the outcomes and characterize the optimal spatial policies.Agglomeration, Space, Pollution, Environmental Policy, Knowledge Spillovers, Transportation Cost

Teaching Eros: The Rhetoric of Love in the 'Tale of Livistros and Rodamne,' the 'Roman de la Rose,' and the 'Hypnerotomachia Poliphili'

The paper brings together three rather unlikely texts, the thirteenth-century Byzantine romance The Tale of Livistros and Rodamne, the thirteenth-century Old French Roman de la Rose, and the fifteenth-century Italian prose romance Hypnerotomachia Poliphili, which are characterized by their lengthy dream narratives in which a first-person narrator is initiated in the art and the mysteries of love. Focusing on a group of instructive speeches contained within or indirectly connected with these dream narratives, this paper examines instruction as an integral component of the initiation process and as a powerful rhetorical tool moving the narrative – and the love story of the protagonist couple – forward. In doing so, the paper also highlights the ideas about love expressed in each of the three romances, the ways that they interconnect and the ways that they differ

Studying salicylic acid function in natural accessions of Arabidopsis thaliana using CRISPR/Cas technology

The plant hormone salicylic acid (SA) has been used for millennia to relieve pain. In modern times, its acetylate form – known as aspirin – has become one of the most popular painkillers. SA production in plants has been implicated in multiple aspects of plant life including thermogenesis, response to stresses, seed viability, leaf senescence, flowering time regulation and immune responses. It has been reported that regulation of SA accumulation exhibits natural variation, for example due to the positive regulator ACCELERATED CELL DEATH 6 (ACD6). But still little is known regarding variation of the main biosynthetic pathway of SA, its involvement in flowering time regulation or its effect regarding the virulence of microbes. To elucidate natural variation in the synthesis of SA and its effect on other processes, I utilised a newly introduced genome editing approach called CRISPR/Cas system. This tool allows the user to edit a targeted region using an endonuclease (Cas9) and an artificial RNA (sgRNA). With this method I selectively knocked out the ICS1 gene and disrupted the main SA biosynthetic pathway in seven natural accessions of A. thaliana. To efficiently screen the large number of individuals that required genotyping for this workflow (>900) I developed a preparation and analysis pipeline using deep amplicon sequencing (CRISPR-finder). Using this pipeline, individuals carrying variants at the targeted region can be identified within a few days in a cost-effective and precise manner. Using the ics1 lines I generated, in spite of the non-functional ICS1 allele, I was able to detect residual SA in most of the lines. These results suggested that the alternative PAL biosynthetic pathway or the ICS2 gene may be responsible for appreciable levels of SA production in some genotypes. Additionally, I concluded that flowering time was not significantly affected by decreased levels of SA in these seven natural accessions, even though SA had been linked to flowering before. Significant reduction of SA accumulation was observed for all the mutant lines, but to different degrees, when compared to the corresponding wild types, during Pseudomonas syringae (Psm4326) infection. When the oomycete Hyaloperonospora arabidopsidis (14OHMLP04) was used for infecting individuals, no significant induction of SA accumulation was detected when plants exhibited resistance (flecking necrosis or trailining necrosis) or susceptibility. For the genotypes characterised with complete resistance (flecking necrosis) no effect of SA was observed. Interestingly, increased severity of trailing necrosis was observed for the ics1 mutant lines derived from partially resistant genotypes (trailing necrosis symptom). There were also accessions and their corresponding ics1 mutant lines that showed susceptibility and pathogen growth. These findings suggest that resistance to the pathogen isolate is SA-independent and that decreased levels of SA allow an increased manifestation of the potential virulence of 14OHMLP04. Finally, the commonly used Col-0 accession was used for investigating a controversial aspect of the CRISPR/Cas system – off-target cleavage. This can occur due to non specific Cas9 activity. For assessing off-target variants, I used the same sgRNAs as the ones used for generating the ics1 mutant lines. During the investigation, I was able to detect a very small number of incidents (0, 2 and 5 depending on the line in question) that could potentially be attributed to Cas9’s cleavage activity. These numbers do not differ dramatically from the expected de novo mutation rate in A. thaliana which is approximately one mutation per generation. This makes it hard to confidently assign detected variants to Cas9 cleavage or de novo generation. These findings do not exclude that off-target cleavage events can occur when the CRISPR/Cas system is used, but they are rare and may be difficult to detect

Regulating Discourse: How Children With and Without SEND Internalize the Evaluative Framework of Adults

This study presents a Bakhtinian analysis of discourse among children with Special Educational Needs and Disorders (SEND) in two elementary classrooms, delving into the complicated interaction of voices and perspectives within their communication. The research investigates how the evaluation of peers provides a contextual backdrop for the voices of children with SEND. Conducted as a longitudinal investigation in an English primary school, data were collected over a three-month period to disclose communication dynamics. Notably, the discourse analysis reveals the use of “hybrid constructions” by students, wherein they skillfully blend adult values with their own viewpoints when discussing peers, thus navigating their positioning vis-à-vis institutional norms and their peers. The central question, “Who is taking the lead in the conversation?” undrapes a rich interchange of voices within each dialog excerpt. This interaction encompasses the speaker’s own voice and resonates with reflections of institutional discourse. Importantly, the analysis elucidates how diverse pedagogic discourses contribute to shaping social relationships between teachers and students, as well as amongst the students themselves. By capturing these multifaceted interactions, this study reveals a paramount conduit through which institutional values are communicated and internalized within the discourse of children with SEND. This focused exploration contributes to a nuanced understanding of how children assimilate external voices while communicating and how they forge connections with peers facing unique learning challenges