The principle of least effort within the hierarchy of linguistic preferences: external evidence from English

The thesis is an investigation of the principle of least effort (Zipf 1949 [1972]). The principle is simple (all effort should be least) and universal (it governs the totality of human behavior). Since the principle is also functional, the thesis adopts a functional theory of language as its theoretical framework, i.e. Natural Linguistics. The explanatory system of Natural Linguistics posits that higher principles govern preferences, which, in turn, manifest themselves as concrete, specific processes in a given language. Therefore, the thesis’ aim is to investigate the principle of least effort on the basis of external evidence from English. The investigation falls into the three following strands: the investigation of the principle itself, the investigation of its application in articulatory effort and the investigation of its application in phonological processes. The structure of the thesis reflects the division of its broad aims. The first part of the thesis presents its theoretical background (Chapter One and Chapter Two), the second part of the thesis deals with application of least effort in articulatory effort (Chapter Three and Chapter Four), whereas the third part discusses the principle of least effort in phonological processes (Chapter Five and Chapter Six). Chapter One serves as an introduction, examining various aspects of the principle of least effort such as its history, literature, operation and motivation. It overviews various names which denote least effort, explains the origins of the principle and reviews the literature devoted to the principle of least effort in a chronological order. The chapter also discusses the nature and operation of the principle, providing numerous examples of the principle at work. It emphasizes the universal character of the principle from the linguistic field (low-level phonetic processes and language universals) and the non-linguistic ones (physics, biology, psychology and cognitive sciences), proving that the principle governs human behavior and choices. Chapter Two provides the theoretical background of the thesis in terms of its theoretical framework and discusses the terms used in the thesis’ title, i.e. hierarchy and preference. It justifies the selection of Natural Linguistics as the thesis’ theoretical framework by outlining its major assumptions and demonstrating its explanatory power. As far as the concepts of hierarchy and preference are concerned, the chapter provides their definitions and reviews their various understandings via decision theories and linguistic preference-based theories. Since the thesis investigates the principle of least effort in language and speech, Chapter Three considers the articulatory aspect of effort. It reviews the notion of easy and difficult sounds and discusses the concept of articulatory effort, overviewing its literature as well as various understandings in a chronological fashion. The chapter also presents the concept of articulatory gestures within the framework of Articulatory Phonology. The thesis’ aim is to investigate the principle of least effort on the basis of external evidence, therefore Chapters Four and Six provide evidence in terms of three experiments, text message studies (Chapter Four) and phonological processes in English (Chapter Six). Chapter Four contains evidence for the principle of least effort in articulation on the basis of experiments. It describes the experiments in terms of their predictions and methodology. In particular, it discusses the adopted measure of effort established by means of the effort parameters as well as their status. The statistical methods of the experiments are also clarified. The chapter reports on the results of the experiments, presenting them in a graphical way and discusses their relation to the tested predictions. Chapter Four establishes a hierarchy of speakers’ preferences with reference to articulatory effort (Figures 30, 31). The thesis investigates the principle of least effort in phonological processes, thus Chapter Five is devoted to the discussion of phonological processes in Natural Phonology. The chapter explains the general nature and motivation of processes as well as the development of processes in child language. It also discusses the organization of processes in terms of their typology as well as the order in which processes apply. The chapter characterizes the semantic properties of processes and overviews Luschützky’s (1997) contribution to NP with respect to processes in terms of their typology and incorporation of articulatory gestures in the concept of a process. Chapter Six investigates phonological processes. In particular, it identifies the issues of lenition/fortition definition and process typology by presenting the current approaches to process definitions and their typology. Since the chapter concludes that no coherent definition of lenition/fortition exists, it develops alternative lenition/fortition definitions. The chapter also revises the typology of phonological processes under effort management, which is an extended version of the principle of least effort. Chapter Seven concludes the thesis with a list of the concepts discussed in the thesis, enumerates the proposals made by the thesis in discussing the concepts and presents some questions for future research which have emerged in the course of investigation. The chapter also specifies the extent to which the investigation of the principle of least effort is a meaningful contribution to phonology.

Re-viewing history: antiquaries, the graphic arts and Scotland's lost geographies, c.1660-1820

This thesis examines topographical art depicting Scotland’s natural scenery and built environments, architecture, antiquities and signs of modern improvement, made during the period 1660 to 1820. It sets out to demonstrate that topography and topographical art was not exclusively antiquarian in nature, but ranged across various fields of learning and practice. It included the work of artists, geographers, cartographers, travel writers, poets, landscape gardeners, military surveyors, naturalists and historians who were concerned with representing the country’s varied, and often contentious, histories within an increasingly modernising present. The visual images that are considered here were forms of knowledge that found expression in drawings, paintings and engravings, elevations, views and plans. They were made on military surveys and picturesque tours, and were often intended to be included alongside written texts, both published and unpublished, frequently connecting with travels, tours, memoirs, essays and correspondence. It will also be argued that topography was a social practice, involving networks of artists, collectors, publishers and writers, who exchanged information in drawings and letters in a nationwide, and often increasingly commercial enterprise. This thesis will explore some of the strands of such a vast network of picture-making that existed in Scotland, and Britain, between 1660 and 1820, as visual images were circulated, copied, recycled and adapted, and topographical and antiquarian visual culture emerges as a complex, synoptic form of inquiry.

É preciso ter coragem: um estudo das narrativas de mulheres na política

É na busca por compreender a inserção e participação de mulheres na política partidária na contemporaneidade que esta dissertação, situada na linha de pesquisa Culturas, Linguagens e Utopias, tem como objetivo analisar as narrativas de vereadoras de municípios que estão localizados na região sul do Rio Grande do Sul no período de 2009-2012. O corpus de análise constitui-se de entrevistas individuais semiestruturadas com as onze vereadoras participantes a partir da metodologia de investigação narrativa. Partindo das contribuições dos Estudos Culturais e de Gênero em suas vertentes pós-estruturalistas procurou-se problematizar alguns discursos e práticas que emergiram nas narrativas com base nas contribuições da análise do discurso de Michel Foucault. Assim, verificou-se que a representação cultural das mulheres neste campo político está fundamentada em concepções essencialistas do gênero feminino como a sensibilidade. Isso vem provocando discussões na ciência política e nos estudos de gênero a partir de termos como política de ideias, política de desvelo que discutem a presença das mulheres em decorrência ou não desses atributos. O fato é que esses discursos vêm instituindo diferenças na participação de homens e mulheres na política e constituindo formas de ser mulher na política partidária e de fazer política diferenciada das dos homens de forma menos “dura”, “rígida”. Ao debruçar-se na inserção das mulheres nessa esfera pública constatou-se uma trajetória marcada pelas noções de público e privado que impediu ao longo de nossa história a participação das mulheres no campo político e o desenvolvimento de sua cidadania. Além disso, nas narrativas das vereadoras fica evidente que as mulheres não foram constituídas para participarem do que hoje é um direito seu: a esfera pública de decisão da política. Isso foi constatado a partir do convite que foi feito para a candidatura pelos partidos que a partir das cotas partidárias procuraram mais significativamente por mulheres para concorrer. Também se observou neste estudo o capital político de ingresso das mulheres nessa esfera: o capital familiar, capital dos movimentos sociais e capital de ocupação em cargos públicos. Quanto a participação das mulheres no cotidiano de seus mandatos identificamos a dificuldade de ser mulher e política na atualidade. As negociações com os partidos e os colegas, a conciliação entre a família e a vida pública; os focos de atuação dedicados as áreas sociais e nesse destacamos mais significativamente a educação. Por fim, o que pretendemos foi desconfiar da máxima “lugar de mulher não é na política” e conhecer as trajetórias e histórias de mulheres que cotidianamente entre conflitos e disputas lutam pelo seu lugar na esfera pública, pelo exercício de sua cidadania.

Développement de matériaux à base de protéines extraites du byssus de la moule bleue Mytilus edulis

Le byssus est un amas de fibres que les moules produisent afin de s’ancrer aux surfaces immergées sous l’eau. Ces fibres sont pourvues de propriétés mécaniques impressionnantes combinant rigidité, élasticité et ténacité élevées. De plus, elles possèdent un comportement d’auto-guérison de leurs propriétés mécaniques en fonction du temps lorsque la contrainte initialement appliquée est retirée. Les propriétés mécaniques de ces fibres sont le résultat de l’agencement hiérarchique de protéines de type copolymère blocs riches en collagène et de la présence de métaux formant des liens sacrificiels réversibles avec certains acides aminés comme les DOPA et les histidines. Bien que cette fibre soit très intéressante pour la production de matériaux grâce à son contenu élevé en collagène potentiellement biocompatible, cette ressource naturelle est traitée comme un déchet par les mytiliculteurs. L’objectif de cette thèse était de valoriser cette fibre en extrayant les protéines pour générer une nouvelle classe de matériaux biomimétiques. Un hydrolysat de protéines de byssus (BPH) riche en acides aminés chargés, i.e. ~30 % mol, et permettant de former des films a pu être généré. Lorsque solubilisé à pH 10.5, le BPH forme un hydrogel contenant des structures en triple hélice de collagène et des feuillets β anti-parallèles intra- et inter-moléculaires. Suite à l’évaporation de l’eau, le film de BPH résultant est insoluble en milieu aqueux à cause des structures secondaires très stables agissant comme points de réticulation effectifs. Les propriétés mécaniques des films de BPH sont modulables en fonction du pH. Au point isoélectrique (pI = 4.5), les interactions électrostatiques entre les charges opposées agissent comme points de réticulation et augmentent la rigidité des films et leur contrainte à la rupture sans affecter la déformation à la rupture. À pH plus élevé ou plus bas que le pI, les performances mécaniques des films sont plus faibles à cause de la répulsion entre les groupements fonctionnels de même charge qui interagissent plutôt avec les molécules d’eau et causent le gonflement de la matrice protéique des films. Le BPH contenant un nombre élevé d’acides aminés chargés et réactifs, nous avons pu réticuler les films de manière covalente à l’aide d’EDC ou de glutaraldéhyde. Les propriétés mécaniques des films sont modulables en fonction de la concentration d’EDC utilisée lors de la réticulation ou en employant du glutaraldéhyde comme agent réticulant. Les films sont à la fois plus rigides et plus forts avec un degré de réticulation élevé, mais perdent leur extensibilité à mesure que les segments libres de s’étirer lors d’une traction deviennent entravés par les points de réticulation. La réticulation augmente également la résistance à la dégradation enzymatique par la collagénase, les films les plus fortement réticulés lui étant pratiquement insensibles. La spectroscopie infrarouge montre enfin que la réticulation entraîne une transition de feuillets β anti-parallèles inter-moléculaires vers des structures de type hélices de collagène/PPII hydratées. Des liens sacrificiels ont été formés dans les films de BPH par traitement au pI et/ou avec différents métaux, i.e. Na+, Ca2+, Fe3+, afin de moduler les propriétés mécaniques statiques et d’évaluer le rôle de ces traitements sur le comportement d’auto-guérison lors de tests mécaniques cycliques avec différents temps de repos. Plus la valence des ions métalliques ajoutés augmente, plus les propriétés mécaniques statiques affichent un module, une contrainte à la rupture et une ténacité élevés sans toutefois affecter la déformation à la rupture, confirmant la formation de liens sacrificiels. Les tests mécaniques cycliques montrent que les traitements au pI ou avec Ca2+ créent des liens sacrificiels ioniques réversibles qui mènent à un processus d’auto-guérison des performances mécaniques dépendant du pH. L’ajout de Fe3+ à différentes concentrations module les performances mécaniques sur un plus large intervalle et la nature plus covalente de son interaction avec les acides aminés permet d’atteindre des valeurs nettement plus élevées que les autres traitements étudiés. Le Fe3+ permet aussi la formation de liens sacrificiels réversibles menant à l’auto-guérison des propriétés mécaniques. Les spectroscopies Raman et infrarouge confirment que le fer crée des liaisons avec plusieurs acides aminés, dont les histidines et les DOPA. Les résultats dans leur ensemble démontrent que les films de BPH sont des hydrogels biomimétiques du byssus qui peuvent être traités ou réticulés de différentes façons afin de moduler leurs performances mécaniques. Ils pourraient ainsi servir de matrices pour des applications potentielles dans le domaine pharmaceutique ou en ingénierie tissulaire.

Computationally-guided thermostabilization of the primary endoglucanase from Hypocrea jecorina for cellulosic biofuel production

The creation of thermostable enzymes has wide-ranging applications in industrial, scientific, and pharmaceutical settings. As various stabilization techniques exist, it is often unclear how to best proceed. To this end, we have redesigned Cel5A (HjCel5A) from Hypocrea jecorina (anamorph Trichoderma reesei) to comparatively evaluate several significantly divergent stabilization methods: 1) consensus design, 2) core repacking, 3) helix dipole stabilization, 4) FoldX ΔΔG approximations, 5) Triad ΔΔG approximations, and 6) entropy reduction through backbone stabilization. As several of these techniques require structural data, we initially solved the first crystal structure of HjCel5A to 2.05 Å. Results from the stabilization experiments demonstrate that consensus design works best at accurately predicting highly stabilizing and active mutations. FoldX and helix dipole stabilization, however, also performed well. Both methods rely on structural data and can reveal non-conserved, structure-dependent mutations with high fidelity. HjCel5A is a prime target for stabilization. Capable of cleaving cellulose strands from agricultural waste into fermentable sugars, this protein functions as the primary endoglucanase in an organism commonly used in the sustainable biofuels industry. Creating a long-lived, highly active thermostable HjCel5A would allow cellulose hydrolysis to proceed more efficiently, lowering production expenses. We employed information gleaned during the survey of stabilization techniques to generate HjCel5A variants demonstrating a 12-15 °C increase in the temperature at which 50% of the total activity persists, an 11-14 °C increase in optimal operating temperature, and a 60% increase over the maximal amount of hydrolysis achievable using the wild type enzyme. We anticipate that our comparative analysis of stabilization methods will prove useful in future thermostabilization experiments.

Relatório de estágio

Este relatório destina-se a descrever as acções desenvolvidas no estágio, do 1º Curso de Mestrado em Enfermagem Comunitária, realizado na Escola Superior de Saúde de Portalegre. A intervenção comunitária, realizou-se na comunidade escolar de Portalegre, tendo tido duas vertentes: Educação sexual na adolescência; Promoção de comportamentos saudáveis nos estilos de vida dos adolescentes. As ações realizadas abordaram a educação sexual na adolescência, com base no diagnóstico de situação e, através da elaboração de um projecto de intervenção, aplicado em metodologia de planeamento em saúde. A intervenção comunitária teve como base a promoção de comportamentos saudáveis nos estilos de vida dos adolescentes, a alunos das escolas de Portalegre do 9º e 12º anos, na área de ciências e tecnologias. Todo este trabalho foi desenvolvido na fase teórica e suportou a nossa intervenção em estágio. Assim, após a conclusão deste diagnóstico, seguiu-se a fase de estabelecimento de prioridades, fixação dos objectivos, selecção de estratégias, preparação da execução e avaliação. Na adolescência, a educação sexual deverá ser orientada para a maturação psicossexual, para os afetos, para a contraceção e planeamento familiar e para a prevenção de doenças. É da responsabilidade dos profissionais de saúde, da escola, mas sobretudo da família, proporcionar um ambiente favorável à aprendizagem e ao diálogo. O realce da educação sexual, deverá ser colocado na igualdade de papéis, na tolerância face ao pluralismo de orientação e de condutas sexuais. Por outro lado, é também na adolescência, que se adquirem hábitos e comportamentos saudáveis. Assim, os profissionais de saúde, conjuntamente com a escola e a família, poderão ter um papel preponderante, capacitando os jovens de competências que lhes permitam optar por comportamentos saudáveis, a nível de alimentação, álcool, uso de drogas, prevenção de infecções sexualmente transmissíveis e cidadania

As forças armadas e a segurança interna

A Constituição da República Portuguesa desde 1982, e após sete revisões constitucionais, faz a distinção vincada entre o que é Segurança Interna e Defesa Nacional. Assim, reserva para a primeira a intervenção das Forças da Segurança e para a segunda a as Forças Armadas, permitindo apenas a intervenção destas na Segurança Interna em estados de excepção, como o estado de emergência e o estado de sítio. Dada a delicadeza do tema optou-se pela construção de um questionário, para que as pessoas possam pronunciar-se de forma isenta sobre o tema, sem constrangimentos institucionais. Optou-se por uma abordagem qualitativa. Com base num guião, entrevistaram-se quatro peritos no assunto de forma a obter respostas sobre a viabilidade da intervenção das Forças Armadas na Segurança Interna, num estado de normalidade democrática. As respostas depois de transcritas constituíram o corpus que foi submetido a análise de conteúdo. Com base nesta análise de conteúdo, a partir dos excertos de discursos codificados nas categorias e subcategorias, procedeu-se à construção dos itens que figurarão numa primeira versão do questionário. A primeira versão do questionário apresenta-se em torno de quatro eixos (categorias), que se dividem em subcategorias: intervenção das Forças Armadas na Segurança Interna; legislação; mudança do paradigma de segurança; e, definição conceptual.

Structural and ultrastructural characteristics of interrenal gland and chromaffin cell of matrinxa, Brycon cephalus Gunther 1869 (Teleostei-Characidae)

This work presents the structure and ultrastructure of the interrenal gland and chromaffin cells, as well as the morphology of the head kidney of Brycon cephalus, the head kidney is composed of fused bilateral lobes located anterior to the swim bladder and ventrolateral to the spinal column, the parenchyma revealed lympho-haematopoietic tissue, melano-macrophage centres, interrenal gland and chromaffin cells. The interrenal gland consisted of cords or strands of cells grouped around the posterior cardinal vein and their branches. Chromaffin cells are found in small groups, closely associated with the interrenal gland and/or under the endothelium of the posterior cardinal vein. So far, the ultrastructural analysis has revealed only one interrenal cell type which contained abundant smooth endoplasmic reticulum and numerous mitochondria with tubulo-vesicular cristae, characteristic of steroid-producing cells. Two types of chromaffin cells were observed. The first type was characterized by the presence of vesicles with round, strongly electron-dense granules, which were eccentrically located, Such cells were interpreted as noradrenaline cells, Meanwhile, cells which contained smaller vesicles and electron-lucent granules, with a small halo separating the granule from the vesicular limiting membrane, were identified as adrenaline cells.

Determing the Effect of Thermal Treatment Timing on Ultra-High Performance Concrete Beams

The loss of prestressing force over time influences the long-term deflection of the prestressed concrete element. Prestress losses are inherently complex due to the interaction of concrete creep, concrete shrinkage, and steel relaxation. Implementing advanced materials such as ultra-high performance concrete (UHPC) further complicates the estimation of prestress losses because of the changes in material models dependent on curing regime. Past research shows compressive creep is "locked in" when UHPC cylinders are subjected to thermal treatment before being loaded in compression. However, the current precasting manufacturing process would typically load the element (through prestressing strand release from the prestressing bed) before the element would be taken to the curing facility. Members of many ages are stored until curing could be applied to all of them at once. This research was conducted to determine the impact of variable curing times for UHPC on the prestress losses, and hence deflections. Three UHPC beams, a rectangular section, a modified bulb tee section, and a pi-girder, were assessed for losses and deflections using an incremental time step approach and material models specific to UHPC based on compressive creep and shrinkage testing. Results show that although it is important for prestressed UHPC beams to be thermally treated, to "lock in" material properties, the timing of thermal treatment leads to negligible differences in long-term deflections. Results also show that for UHPC elements that are thermally treated, changes in deflection are caused only by external loads because prestress losses are "locked-in" following thermal treatment.

Use of Fiber Reinforced Polymer Composite Cable for Post-tensioning Application

Corrosion of steel tendons is a major problem for post-tensioned concrete, especially because corrosion of the steel strands is often hard to detect inside grouted ducts. Non-metallic tendons can serve as an alternative material to steel for post-tensioning applications. Carbon fiber reinforced polymer (CFRP), given its higher strength and elastic modulus, as well as excellent durability and fatigue strength, is the most practical option for post-tensioning applications. The primary objective of this research project was to assess the feasibility of the use of innovative carbon fiber reinforced polymer (CFRP) tendons and to develop guidelines for CFRP in post-tensioned bridge applications, including segmental bridges and pier caps. An experimental investigation and a numerical simulation were conducted to compare the performance of a scaled segmental bridge model, post-tensioned with two types of carbon fiber strands and steel strands. The model was tested at different prestress levels and at different loading configurations. While the study confirms feasibility of both types of carbon fiber strands for segmental bridge applications, and their similar serviceability behavior, strands with higher elastic modulus could improve structural performance and minimize displacements beyond service loads. As the second component of the project, a side-by-side comparison of two types of carbon fiber strands against steel strands was conducted in a scaled pier cap model. Two different strand arrangements were used for post-tensioning, with eight and six strands, respectively representing an over-design and a slight under-design relative to the factored demand. The model was tested under service and factored loads. The investigation confirmed the feasibility of using carbon fiber strands in unbonded post-tensioning of pier caps. Considering both serviceability and overload conditions, the general performance of the pier cap model was deemed acceptable using either type of carbon fiber strands and quite comparable to that of steel strands. In another component of this research, creep stress tests were conducted with carbon fiber composite cable (CFCC). The anchorages for all the specimens were prepared using a commercially available expansive grout. Specimens withstood 95% of the guaranteed capacity provided by the manufacturer for a period of five months, without any sign of rupture.

Adaptive cultural transmission biases in children and nonhuman primates

Comparative and evolutionary developmental analyses seek to discover the similarities and differences between humans and non-human species that illuminate both the evolutionary foundations of our nature that we share with other animals, and the distinctive characteristics that make human development unique. As our closest animal relatives, with whom we last shared common ancestry, non-human primates have beenparticularly important in this endeavour. Such studies that have focused on social learning, traditions, and culture have discovered much about the ‘how’ of social learning, concerned with key underlying processes such as imitation and emulation. One of the core discoveries is that the adaptive adjustment of social learning options to different contexts is not unique to human infants, therefore multiple new strands of research have begun to focus on more subtle questions about when, from whom, and why such learning occurs. Here we review illustrative studies on both human infants and young children and on non-human primates to identify the similarities shared more broadly across the primate order, and the apparent specialisms that distinguish human development. Adaptive biases in social learning discussed include those modulated by task comprehension, experience, conformity to majorities, and the age, skill, proficiency and familiarity of potential alternative cultural models.

Numerical modelling of braided fibres for reinforced concrete

Fire has been always a major concern for designers of steel and concrete structures. Designing fire-resistant structural elements is not an easy task due to several limitations such as the lack of fire-resistant construction materials. Concrete reinforcement cover and external insulation are the most commonly adopted systems to protect concrete and steel from overheating, while spalling of concrete is minimised by using HPFRC instead of standard concrete. Although these methodologies work very well for low rise concrete structures, this is not the case for high-rise and inaccessible buildings where fire loading is much longer. Fire can permanently damage structures that cost a lot of money. This is unsafe and can lead to loss of life. In this research, the author proposes a new type of main reinforcement for concrete structures which can provide better fire-resistance than steel or FRP re-bars. This consists of continuous braided fibre rope, generally made from fire-resistant materials such as carbon or glass fibre. These fibres have excellent tensile strengths, sometimes in excess of ten times greater than steel. In addition to fire-resistance, these ropes can produce lighter and corrosive resistant structures. Avoiding the use of expensive resin binders, fibres are easily bound together using braiding techniques, ensuring that tensile stress is evenly distributed throughout the reinforcement. In order to consider braided ropes as a form of reinforcement it is first necessary to establish the mechanical performance at room temperature and investigate the pull-out resistance for both unribbed and ribbed ropes. Ribbing of ropes was achieved by braiding the rope over a series of glass beads. Adhesion between the rope and concrete was drastically improved due to ribbing, and further improved by pre-stressing ropes and reducing the slacked fibres. Two types of material have been considered for the ropes: carbon and aramid. An implicit finite element approach is proposed to model braided fibres using Total Lagrangian formulation, based on the theory of small strains and large rotations. Modelling tows and strands as elastic transversely isotropic materials was a good assumption when stiff and brittle fibres such as carbon and glass fibres are considered. The rope-to-concrete and strand-to-strand bond interaction/adhesion was numerically simulated using newly proposed hierarchical higher order interface elements. Elastic and linear damage cohesive models were used effectively to simulate non-penetrative 'free' sliding interaction between strands, and the adhesion between ropes and concrete respectively. Numerical simulation showed similar de-bonding features when compared with experimental pull-out results of braided ribbed rope reinforced concrete.

Occurrence of plastic debris in the stomach of the invasive crab Eriocheir sinensis

The Chinese mitten crab is known as a pest causing damage to fishing gears and fish. On the other hand, this highly invasive species is considered a delicacy by Asian migrants and therefore commercially fished and sold in many countries. The ingestion of plastic by the Chinese mitten crab Eriocheir sinensis from the Baltic coastal waters (Poland) and the Tagus Estuary (Portugal) was studied based on stomach content analysis. As many as 13% of the 302 analysed males and females (38.07–89.07 mm carapace width) from both regions, contained microplastic in the form of strands and balls. Most of them were transparent. Ingested plastic particles were identified as fragments of fishing gears. Contamination with plastic may have a negative impact on this species as well as on higher trophic levels feeding on crabs.

Dall'uomo esposto al soggetto esposto: il concetto di interfaccia in alcuni filoni di riflessione sulla tecnica dal Settecento a Marcel Mauss

La nozione di ambiente non è una nozione recente. Al giorno d’oggi il riferimento all’ambiente compare in maniera sempre più diffusa nei dibattiti, nelle opere scientifiche e artistiche, negli spazi di divulgazione e sempre più entra all’interno degli spazi affettivi individuali e all’interno delle teorie e delle prassi politiche individuali e collettive. L’ambiente tanto entra nel campo assiologico, quanto vi entra come elemento fragile, indissociabile dall’azione antropica individuale e collettiva, attraverso ciò che noi riassumiamo con la nozione di crisi ambientale. La crisi ambientale permette di riaprire degli ambiti di valore e di interesse nel presente, allo stesso tempo provoca una reinterpretazione e un riorientamento delle teorie e delle prassi del passato. Dal nostro presente di crisi ambientale, è possibile rintracciare delle figure che, nel passato, hanno rappresentato l’inerenza degli enti con il loro ambiente e, tra questi, dell’uomo con il suo ambiente di vita. Sono due le principali figure attraverso le quali si intende riprendere un rapporto con il nostro passato letto attraverso la crisi ambientale: la figura dell’interfaccia come ciò che demarca un rapporto di inerenza e di separazione tra un interno e un esterno che hanno un rapporto tra loro necessario e tuttavia contingente, e la figura della relazione di “esposizione”, tramite la quale si vuole pensare a forme di soggettività vulnerabili, esposte alle relazioni e ai concatenamenti nei quali sono inserite e che tuttavia non possono che esporre a loro volta le altre soggettività e l’ambiente di vita comune a continue modificazioni. Tramite i concetti di interfaccia e di esposizione abbiamo potuto seguire il prodursi di forme di sapere relative all’inerenza tra forme e modi dell’interiorità rispetto all’ambiente che si sono prodotte nella storia e che sono emerse tramite la provocazione di un passato indotto dalla trasformazione che è il nostro presente di crisi ambientale.

Simulating the aggregation of DNA oligonucleotides

In this work we have studied, by means of Molecular Dynamics simulations, the process of denaturation and self-assembly of short oligonucleotides. Supramolecular ordering of DNA short strands is a promising field which is constantly enriched with new findings. Examples are provided by micellar and fibrils formations and due to the selectivity of DNA bindings, "intelligent" devices have been developed to perform simple logic operations. It is worth to notice that computer simulations of these DNA nanosystems would complement experiments with detailed insight into processes involved in self-assembly. In order to obtain an accurate description of the interactions involved in the complex structure of DNA we used oxDNA, a coarse-grained model developed by Ouldridge. We simulated the melting transition of 4, 6, and 8 base pair sequences. Sequence and length dependence were analyzed, specifically we compared thermodynamic parameters DeltaH, DeltaS and the melting temperature with literature results. Moreover, we have attempted to reproduce liquid crystal ordering of the ultrashort sequence GCCG at relatively high saline concentration, until now only experimentally observed in Bellini's works. We found that our simple model successfully reproduces the experimental phase sequence (isotropic, nematic, columnar) at T= 5 °C as a function of oligonucleotide concentration, and we fully characterized the microscopic structure of the three phases.