616 research outputs found
The -th derivatives of the immanant and the -symmetric power of an operator
In recent papers, R. Bhatia, T. Jain and P. Grover obtained formulas for
directional derivatives, of all orders, of the determinant, the permanent, the
-th compound map and the -th induced power map. In this paper we
generalize these results for immanants and for other symmetric powers of a
matrix
Zizi Papacharissi (2010, Malden, MA: Polity Press), A Private Sphere: Democracy in a Digital Age
A Private Sphere: Democracy in a Digital Age by Zizi Papacharissi deals with new civic habits that have emerged from the relationship between democracy and technology, attempting to understand the way in which technology transforms..
Infeções urinárias em felídeos e canídeos: etiologia e resistência aos antimicrobianos
As infeções urinarias são das patologias mais frequentes nos animais de companhia, são geralmente
causadas por bactérias e o seu tratamento depende da utilização de antimicrobianos.
Este estudo, realizado no âmbito de um estágio, teve como objetivo identificar a etiologia destas infeções
em felídeos e canídeos, bem como estudar a sensibilidade aos antimicrobianos nos agentes etiológicos
identificados.
Foram incluídos neste estudo 119 animais, 67 canídeos e 52 felídeos. Os agentes etiológicos mais
frequentes nos canídeos foram Escherichia coli (44,78%), Proteus mirabilis (16,42%) e Staphylococcus
pseudintermedius (10,45%). Nos felídeos foram a Escherichia coli (55,77%), Enterococcus faecalis
(11,54%), e Staphylococcus coagulase negativa (5,77%).
Neste estudo a E.coli, agente etiológico mais frequente, apresenta resistência a cefalexina (1ºgeração)
superior a 90% quer nos canídeos quer nos felídeos. Nos canídeos, verificou-se ainda resistência a 6 dos
19 antibióticos testados nos isolados de Staphylococcus aureus e nos felídeos observou-se resistência a
5 dos 15 antibioticos testados nos isolados de E.faecalis. A determinação precisa do agente e respectivo
antibiograma, é relevante não só para a saúde dos próprios animais como a nível de Saúde Pública. A
escolha do antimicrobiano mais adequado para o tratamento previne o aparecimento de resistências
bacterianas, um dos maiores desafios de Saúde Pública
An assessment of the portuguese OTC market network structure under EMIR - Bringing light to the portuguese OTC CDS Market
Project Work proposal presented as partial requirement for obtaining the Master’s degree in Information Management, with a specialisation in Knowledge Management and Business IntelligenceHere we provide a data-driven network analysis of the Over-the-Counter (OTC) Portuguese
Market under the European Market Infrastructure Regulation (EMIR). We do it so from the
point of view of the Regulator, thus focusing in how different regulation instruments can be
improved through a network abstraction and analysis of the OTC market. Such approach, we
argue, can allow regulators to answer complex questions: Who are the players in the Portuguese
OTC Credit Default Swps (CDS) Market, and how is it structured?
In this paper we provide, as a starting point, the study and characterisation of the OTC CDS
Derivatives Market. By using a multi-segment approach, we were able to build three networks
that represent the Portuguese OTC CDS Market: (1) PT Products + PT Participants segment;
(2) PT Products segment; and (3) PT Participants segment. The analysis of the first two
networks showed that activity, at its scale, is very similar to the European landscape, highly
clustered in a small number of counterparties, with the Central Counterparties (CCPs) and the
entities of the Group of 16 (G16) assuming the leading positions while the counterparties of the
United Kingdom have the lion share in the OTC CDS Derivatives Market. However, when we
place the focus only on the PT Participants segment, e.g., Portuguese players active in the
OTC CDS the CCPs are replaced by Banks and there is a clear preference for the non-domestic
Market and non-cleared transactions.A nossa análise de rede baseada em dados do Mercado de Balcão (OTC) português ao abrigo
do Regulamento Europeu de Infraestrutura de Mercado (EMIR) do ponto de vista do regulador,
com enfoque em como diferentes instrumentos de regulamentação podem ser aprimorados por
meio de uma abstração de rede e análise do Mercado OTC.
Argumentamos que essa abordagem pode permitir que os reguladores respondam a perguntas
complexas: quem são os participantes no Mercado OTC Credit Default Swaps (CDS)
português e como está estruturado?
Neste documento, fornecemos, como ponto de partida, o estudo e a caracterização do Mercado
OTC CDS português. Recorrendo a uma abordagem multissegmento, permitiu-nos construir
três redes que representam o Mercado OTC CDS português: (1) PT Products + PT
Participants segment; (2) PT Products segment; e (3) PT Participants segment. A análise das
primeiras duas redes mostrou que a atividade, à sua escala, é muito semelhante ao panorama
europeu, altamente concentrada num pequeno número de contrapartes, em que as Contrapartes
Centrais (CCPs) e as entidades do Grupo dos 16 (G16) assumem as posições de liderança,
enquanto que as contrapartes do Reino Unido ocupam um lugar primordial no Mercado de
Derivados OTC CDS. No entanto, quando o foco são as transações de contrapartes portuguesas
em Mercados de Derivados OTC CDS (PT Participants), as CCPs são substituídas pelos
Bancos e a preferência recai sobre os mercados não domésticos e transações sem compensação
Formulações à base de solventes eutécticos profundos para o desenvolvimento de sistemas de administração de fármacos
The pharmaceutical industry is characterized by constant changes and demands, driven by the need to develop new drugs, or drug formulations of existing drugs, that are more efficient and safer. In this context, strategies such as drug reformulation are frequently applied to overcome many of the drawbacks associated with the existing pharmaceuticals, given the lower cost of this approach.
Approaches to enhance drug solubility, stability, and permeation are crucial to improve their therapeutic efficacy. Therefore, understanding the problems associated with the existing active pharmaceutical ingredients, developing more effective strategies for their solubilization and administration, as well as to select proper solvents or excipients, are main aspects to improve therapeutic efficacy. Additionally, the possibility to incorporate these components, namely the solvents, in the drug delivery system, to tune their properties is appealing.
Recently, alternative solvents, such as deep eutectic solvents (DES), have been explored in the pharmaceutical field, showing high solvation ability and high drug permeation across biological membranes, as well as drug stabilization. Furthermore, the versatility displayed by these solvents enables their incorporation into different drug delivery systems, being even possible the use of hydrophilic biopolymers. This partnership results in positive effects in the properties of biopolymer-based materials, allowing to particularly tune the mechanical properties and the respective drug release profiles.
In this context, the main goal of this thesis is focused on the development of DES formulations of existing drugs and their incorporation in delivery systems, envisioning the improvement of their efficacy. The works developed involved the rational design of these formulations and the evaluation of their impact on system’s performance. Given the rising concerns associated with antimicrobial agents, including antibiotics, this was the class mainly studied.
The first study focused on the development of DES aqueous solutions of cholinium chloride:urea:malonic acid, proline:urea:malonic acid and citric acid:xylitol, to remarkably improve the solubility, stability, and therapeutic efficacy of the antibiotic ciprofloxacin. The developed formulations enhanced the drug solubility up to 430-fold, in comparison to water, and the susceptibility of Gram-negative and Gram-positive bacteria to ciprofloxacin by 2- to 4-fold, respectively, while being non-toxic to human cells at the studied concentrations.
The ability to improve the therapeutic efficacy of the antibiotic while avoiding the development of antimicrobial tolerance was demonstrated.
The following study aimed to use betaine-based DES aqueous solutions, such as betaine:glycerol and betaine:xylitol, in the development of ocular drug delivery systems, namely thermo-responsive microemulsions that increase their viscosity upon contact with the ocular environment. These systems allowed a sustained-release and a higher permeation of the antibiotic chloramphenicol through the cornea. Finally, a higher antimicrobial activity and faster action in case of infection caused by multi-resistant bacteria was demonstrated using these microemulsions in comparison to a commercialized formulation.
The versatility of DES formulations was also explored in the development of biopolymer-based drug delivery systems. In this sense, pullulan-based adhesive films were developed for application in antimicrobial photodynamic therapy (aPDT). For this purpose, betaine-based DES (betaine:levulinic acid) were applied to improve the solubility and photostability of the natural photosensitizer, curcumin. The incorporation of the DES formulations in the films, permitted to tune pullulan’s properties, obtaining systems with higher extensibility than the pristine materials. These films also present capability to absorb skin moisture and transit into a hydrogel with and higher adhesiveness than commercial hydrogels. The use of these systems in combination with an aPDT approach, allowed to eradicate common drug-resistant strains below the detection limit in ex vivo skin samples while being non-toxic to skin cells.
The partnership between DES and biopolymers was also investigated for the transdermal delivery of anti-inflammatory drugs. DES aqueous solutions, based on arginine:glycerol, were used to increase the solubility of ibuprofen (up to 7917-fold, in comparison to water). These formulations were non-cytotoxic to macrophages and shown to preserve the anti-inflammatory action of the drug. Their incorporation into alginate-based hydrogels resulted in materials with higher flexibility, that presented a sustained release of the drug. Additionally, these hydrogels promoted an enhancement in the drug permeation across human skin in comparison to their counterpart containing only ibuprofen.
In conclusion, the present thesis demonstrates the versatility and advantages of DES formulations in the improvement of drug delivery and therapeutic efficacy of known drugs.A indústria farmacêutica é caraterizada por mudanças e exigências constantes, originadas pela necessidade de desenvolver novos fármacos, ou formulações de fármacos existentes, que sejam mais eficazes e seguras. Neste contexto, são frequentemente utilizadas estratégias como a reformulação farmacêutica para ultrapassar muitas das desvantagens associadas aos fármacos existentes, dado o menor custo desta abordagem.
As estratégias usadas para aumentar a solubilidade, estabilidade e permeação de fármacos são cruciais para melhorar a sua eficácia terapêutica. Assim, compreender os problemas associados aos princípios ativos já existentes, desenvolver estratégias mais eficazes para a sua solubilização e administração, assim como a seleção de solventes ou excipientes apropriados, são aspetos cruciais para melhorar a eficácia terapêutica. Adicionalmente, a possibilidade de incorporar estes componentes, nomeadamente os solventes, em sistemas de administração de fármacos é apelativa para modelar as suas propriedades.
Recentemente, solventes alternativos como os solventes eutécticos profundos (DES) têm sido explorados na área farmacêutica, mostrando uma elevada capacidade de solvatação e de permeação de fármacos através de membranas biológicas, bem como da sua estabilização. Adicionalmente, a versatilidade destes solventes possibilita a sua incorporação em diferentes sistemas de administração de fármacos, sendo inclusive possível o uso de biopolímeros hidrofílicos. Esta combinação resulta em efeitos positivos nas propriedades dos materiais biopoliméricos, permitindo em particular o ajuste das suas propriedades mecânicas e dos perfis de libertação dos respetivos fármacos.
Neste contexto, o principal objetivo da presente tese centrou-se no desenvolvimento de formulações de DES e na sua utilização em novos sistemas de administração de fármacos já existentes, visando a melhoria da sua eficácia. Os trabalhos desenvolvidos envolveram o design racional dessas formulações e a avaliação do seu impacto no desempenho do sistema. Dada as crescentes preocupações associadas aos agentes antimicrobianos, incluindo antibióticos, esta classe de fármacos foi uma das mais estudadas.
O primeiro trabalho focou-se no desenvolvimento de soluções aquosas de DES, tais como cloreto de colina:ureia:ácido malónico, prolina:ureia:ácido malónico e ácido cítrico:xilitol, para melhorar a solubilidade, a estabilidade e a eficácia terapêutica do antibiótico ciprofloxacina.As formulações desenvolvidas permitiram aumentar a solubilidade do fármaco 430 vezes comparativamente à sua solubilidade em água, e a suscetibilidade de bactérias Gram-negativas e Gram-positivas à ciprofloxacina 2 a 4 vezes, respetivamente, sendo não tóxicas para células humanas nas concentrações estudadas. Foi ainda demonstrada a capacidade de melhorar a eficácia terapêutica do antibiótico sem promover o desenvolvimento de tolerância antimicrobiana ao mesmo.
O trabalho seguinte teve como objetivo a utilização de soluções aquosas de DES à base de betaína, nomeadamente betaína:glicerol e betaína:xilitol, no desenvolvimento de sistemas de administração de fármacos para administração ocular, especificamente microemulsões com carácter termo-responsivo, cuja viscosidade aumenta quando em contato com o ambiente ocular. Estes sistemas permitiram obter uma libertação contínua e uma maior permeação do antibiótico cloranfenicol através da córnea. Por fim, foi demonstrada uma maior atividade antimicrobiana e uma ação mais rápida em caso de infeção por bactérias multirresistentes, usando estas microemulsões, comparativamente com uma formulação comercial.
A versatilidade das formulações aquosas de DES foi também explorada no desenvolvimento de sistemas tópicos de administração de fármacos à base de biopolímeros. Neste sentido, foram desenvolvidos filmes adesivos baseados em pululano para aplicação em terapia fotodinâmica antimicrobiana (TFDa). Com este propósito, foram utilizados DES à base de betaína (betaína:ácido levulínico)) para melhorar a solubilidade e fotoestabilidade da curcumina, um fotossensibilizador natural. A incorporação das formulações de DES nos filmes de pululano permitiu ajustar as suas propriedades, tendo-se obtido sistemas com maior extensibilidade do que os correspondentes originais. Estes filmes possuem ainda capacidade de absorver a humidade da pele e passar para a forma de hidrogel com maior adesividade do que os hidrogéis comerciais. O uso destes sistemas em combinação com uma abordagem de TFDa permitiu erradicar estirpes resistentes a antibióticos comuns, abaixo do limite de deteção do método, em amostras de pele ex vivo, sendo estes sistemas não tóxicos para as células da pele.
A combinação de DES e biopolímeros foi também investigada para a administração transdérmica de fármacos anti-inflamatórios. Foram utilizadas soluções aquosas de DES à base de arginina:glicerol para aumentar a solubilidade do ibuprofeno (até 7917 vezes em comparação com a solubilidade em água). Estas formulações não apresentaram citotoxicidade para macrófagos e preservaram a ação anti-inflamatória do fármaco. A sua incorporação em hidrogéis de alginato resultou em materiais com maior flexibilidade, e que apresentam uma libertação sustentada do fármaco. Adicionalmente, estes hidrogéis promoveram um aumento da permeação do fármaco na pele humana em comparação com o sistema homólogo contento apenas ibuprofeno.
Em suma, a presente tese demonstra a versatilidade e as vantagens das formulações aquosas de DES na melhoria da administração e na eficácia terapêutica de diferentes fármacos existentes.Programa Doutoral em Bioquímic
Environmental diplomacy: from transnational policies to the role of ambassadors – the contribution of David Attenborough (2018–2020)
Purpose – The concept of environmental diplomacy appears associated with events (conventions) promoted
between states and transnational organisations to discuss aspects related to regulating the use of natural
resources and regulating pollution. In this study, the authors intend to highlight the contribution brought to
environmental diplomacy by leading television figure David Attenborough and his focus on the destruction of
biodiversity by humans (the problem). It is intended to analyse the frames of his public interventions,
comparing them with the prevailing frames in the UNFCCC policies.
Design/methodology/approach – A predominantly inductive method of qualitative and interpretative
nature is used. In epistemological terms, the framing analysis stems from a social constructivist perspective.
A theoretical model for frame analysis was defined by combining the frameworks proposed by Entman (1993)
and Semetko and Valkenburg (2000) and considering previous studies (Anholt, 2015; Seelig, 2019). Analysis
scrutinised a two-fold corpus comprising articles regarding actions and statements by David Attenborough
published in The Guardian between 2018 and 2020, and the UN’s legal framework for climate change.
Findings – The most prominent frames regarding climate crisis in transnational policies are responsibilities.
Attenborough’s calls for action highlight the frames of “morality”, “responsibilities” and “problems”. However, it is
necessary to make a distinction between the discourse used in transnational treaties and that by Attenborough. In
the former, discourse is more technical and impersonal, presented in a structure of legal diplomas and barely
accessible to the public. In contrast, Attenborough’s speech is more emotional, appealing and sometimes dramatic.
His message is transmitted straightforwardly to the public in a pedagogical, personal tone.
Social implications – The choice of high-profile personalities like David Attenborough as ambassadors has
implications in the visibility of the environmental cause, and in the multiplication of initiatives that denounce
environmental degradation.
Originality/value – This study explores and analyses the narrative construct regarding climate change as
carried out by a trusted and respected media voice. The authors intend to contribute to understanding the
amplification role of public figures in controversial issues and diplomatic matters. The main contribution of this
study is to highlight the strategic nature of the choice of SDA by political powers to voice the drama of climate
emergency.info:eu-repo/semantics/publishedVersio
First records of fishing gear incrustated in corals and gorgonians from the Atlantic coast of Portugal
Plastic pollution is now in the public and scientific domain as an emerging issue of global concern due
to their potential effects to nature and the society. There is high evidence that plastics are now present
in virtually all aquatic ecosystems and are ingested by several organisms, however, little is known
about their impact on deep marine ecosystems and especially on the deep-sea reefs built by
emblematic cold-water corals species. The occurrence and abundance of these organisms in the
Portuguese Atlantic coast is still largely unknown. During recent sampling campaigns aiming at
mapping these ecosystems in the Portuguese coast, preliminary analyses showed the presence of
nylon plastic lines in the stony cup corals of Dendrophylliidae, in Dendrophilia ramea, and a hook-andline fishing gear incrustated in Gorgonian organisms, in Leptogorgia sarmentosa, collected in two
different areas (north and central coastal area of Portugal, 30-50m depth). The derelict gear is mainly
composed of nets, ropes and lines made of non-biodegradable plastics and have been also reported
as causing tissue loss and fragmentation in corals and gorgonian habitat.
This preliminary assessment reveals that the occurrence of the species in sedimentary grounds makes
it especially vulnerable to bottom contact with fishing gear as bottom trawling and should be better
investigated and communicated to local stakeholders. The spatial distribution of these populations,
as well as a first attempt to characterize its habitat and the levels of plastics will be explored in the
next months as an approach to describe the habitat’s suitability and the vulnerability for the species
in the area. This is a first assessment but further studies are foreseen which include monitoring these
habitats and see how they interact with fishing gears over time in these areas, which will be also
presented and discussed.info:eu-repo/semantics/publishedVersio
A systematic review of behavioral, physiological, and neurobiological cognitive regulation alterations in obsessive-compulsive disorder
Obsessive-compulsive disorder (OCD) is characterized by cognitive regulation deficits. However, the current literature has focused on executive functioning and emotional response impairments in this disorder. Herein, we conducted a systematic review of studies assessing the behavioral, physiological, and neurobiological alterations in cognitive regulation in obsessive-compulsive patients using the PubMed database. Most of the studies included explored behavioral (distress, arousal, and frequency of intrusive thoughts) and neurobiological measures (brain activity and functional connectivity) using affective cognitive regulation paradigms. Our results pointed to the advantageous use of reappraisal and acceptance strategies in contrast to suppression to reduce distress and frequency of intrusive thoughts. Moreover, we observed alterations in frontoparietal network activity during cognitive regulation. Our conclusions are limited by the inclusion of underpowered studies with treated patients. Nonetheless, our findings support the OCD impairments in cognitive regulation of emotion and might help to improve current guidelines for cognitive therapy.This work has been funded by national funds, through the Foundation for Science and Technology
(FCT)—project UIDB/50026/2020 and UIDP/50026/2020—and by the projects NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). S.F. was supported by a combined Ph.D. scholarship from the FCT and the company iCognitus4ALL—IT Solutions, Lda (grant number PD/BDE/127839/2016). The funding sources had not been involved in the study design, the collection, analysis, and interpretation of data, in the writing of the report, and in the decision to submit the article for publication
Creative Video Ads in COVID-19: a path to Social Media Engagement
In the social sciences, particularly in marketing, professors are present with constant challenges, therefore,
they have been looking for new methods to engage students through content in the classroom. However, a
global pandemic COVID-19 that led to the confinement of millions of people worldwide and launched new
challenges for education in social sciences. There was a greater digitization of educational contents.
Therefore, the main objective of this study was to analyse the effects of content creativity on student
engagement through WOW effect mediation. Thus, we presented a video available on YouTube and through
a survey we obtained 178 responses from students of marketing courses. The results were analysed using
PLS-SEM and show that creativity influences the WOW effect and, consequently, students' engagement with
the contents. In this context, this study presents important conclusions for education in social sciences,
specifically in the area of marketing.info:eu-repo/semantics/publishedVersio
- …