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In this work, we give a variation of parameters formula for nonautonomous linear impulsive differential equations with piecewise constant arguments of generalized type. We cover several cases of differential equations with deviated arguments investigated before as particular cases. We also give some examples showing the applicability of our results.

Pattern-triggered immunity (PTI) is a critical defense mechanism employed by plants against pathogen attacks. This study explores the role of PTI induced by the Xyn11/eix fungal elicitor in two commercially valuable Rosaceae species, Prunus persica (peach) and Prunus avium (sweet cherry). Our findings demonstrate that Xyn11/eix triggers two specific defense responses: the increase in ethylene production and the induction of cell death. Furthermore, Xyn11/eix-mediated PTI significantly reduces the susceptibility to Botrytis cinerea infection in both species. The study reveals changes in gene expression patterns after Xyn11/eix treatment. Notably, ACO1 and SARDEF1 genes, involved in ethylene and salycilic acid biosynthesis, respectively, are upregulated in P. persica, but not in P. avium at the time point analyzed. This result suggests a potential role for the ethylene and salicylic acid signaling in Xyn11/mix-mediated PTI in P. persica. Additionally, the research identified functional orthologues of LeEIX2, the receptor for Xyn11/eix in Solanum lycopersicum, within both Prunes genomes. Altogether, these results suggest a remarkable functional convergence between Rosaceae and Solanaceae plants in the Xyn11/eix mediated defense responses although not at the transcriptional level, and opens new avenues for developing novel disease control strategies for stone fruits.

The arrival of invasive species in native communities impacts the structure and functioning of ecosystems, and is considered a critical indicator of loss of biodiversity. Exploring the effects of new species in communities presents challenges addressable through theoretical ecology. Species body size not only shapes trophic relationships, but may also impact predator success and facilitate species coexistence. However, little attention has been paid to the effects of differences in species body size on interactions between native and invasive primary consumers, which could be relevant to their coexistence with higher-level predators. Our aim is to investigate demographic patterns using a dynamic, mechanistic model of two age-structured primary consumers (one invasive and one native) sharing a plant resource and preyed upon by a common predator. In our model, we highlight three crucial phenomena: the structuring of primary consumers into adults and juveniles, reproduction occurring in discrete pulses, and the seasonal addition of new individuals to the population. Hence, the success of one species over the other relies on its reproductive capacity to incorporate individuals in each reproductive cycle. Our simulations reveal that abundance patterns are influenced by body size, suggesting that changes in predator body size could serve as key indicators of shifts in community structure.

Disease severity and drought due to climate change present significant challenges to orchard productivity. This study examines the effects of spring inoculation with Pseudomonas syringae pv. syringae (Pss) on sweet cherry plants, cvs. Bing and Santina with varying defense responses, assessing plant growth, physiological variables (water potential, gas exchange, and plant hydraulic conductance), and the levels of abscisic acid (ABA) and salicylic acid (SA) under two summer irrigation levels. Pss inoculation elicited a more pronounced response in ‘Santina’ compared to ‘Bing’ at 14 days post-inoculation (dpi), and those plants inoculated with Pss exhibited a slower leaf growth and reduced transpiration compared to control plants during 60 dpi. During differential irrigations, leaf area was reduced 14% and 44% in Pss inoculated plants of ‘Bing’ and ‘Santina’ respectively, under well-watered (WW) conditions, without changes in plant water status or gas exchange. Conversely, water-deficit (WD) conditions led to gas exchange limitations and a 43% decrease in plant biomass compared to that under WW conditions, with no differences between inoculation treatments. ABA levels were lower under WW than under WD at 90 dpi, while SA levels were significantly higher in Pss-inoculated plants under WW conditions. These findings underscore the influence on plant growth during summer in sweet cherry cultivars that showed a differential response to Pss inoculations and how the relationship between ABA and SA changes in plant drought level responses.

Cidadania e Desenvolvimento é uma disciplina autónoma e obrigatória nos 2.º e 3.º ciclos do Ensino Básico desde o ano letivo 2018/2019, assumindo-se como uma componente curricular transversal no 1.º Ciclo do Ensino Básico e no Ensino Secundário. Desde que foi implementada, a disciplina tem gerado alguma controvérsia, quer pela sua obrigatoriedade, quer pelos temas que propõe abordar. Em 2020, uma família de Famalicão, invocando o direito à objeção de consciência, impediu os seus dois filhos adolescentes de frequentarem as aulas de CeD. O caso ganhou maior atenção mediática com a publicação, nesse mesmo ano, de dois manifestos assinados por várias personalidades públicas. O primeiro pedia o fim da obrigatoriedade da disciplina e a liberdade de escolha dos pais; o segundo defendia a sua obrigatoriedade. Estes acontecimentos, e a polémica associada, foram objeto de discussão por parte da opinião pública e dos media. O presente estudo pretende analisar a cobertura mediática deste caso a partir de seis jornais nacionais (DN, JN, Observador, Público, Correio da Manhã e Expresso), nas suas versões impressas e online, entre 01 a 30 de setembro 2020, período de maior visibilidade e discussão pública. A partir da análise de 148 peças recolhidas, o estudo ajuda a perceber as visões de escola e de educação que estão em confronto nesta troca de argumentos e a forma como os diferentes media se posicionaram neste debate.

Bacterial canker is an important disease of sweet cherry plants mainly caused by Pseudomonas syringae pv. syringae (Pss). Water deficit profoundly impairs the yield of this crop. Nitric oxide (NO) is a molecule that plays an important role in the plant defense mechanisms. To evaluate the protection exerted by NO against Pss infection under normal or water-restricted conditions, sodium nitroprusside (SNP), a NO donor, was applied to sweet cherry plants cv. Lapins, before they were exposed to Pss infection under normal or water-restricted conditions throughout two seasons. Well-watered plants treated with exogenous NO presented a lower susceptibility to Pss. A lower susceptibility to Pss was also induced in plants by water stress and this effect was increased when water stress was accompanied by exogenous NO. The lower susceptibility to Pss induced either by exogenous NO or water stress was accompanied by a decrease in the internal bacterial population. In well-watered plants, exogenous NO increased the stomatal conductance and the net CO2 assimilation. In water-stressed plants, NO induced an increase in the leaf membranes stability and proline content, but not an increase in the CO2 assimilation or the stomatal conductance.

One of the causal agents of bacterial canker is Pseudomonas amygdali pv. morsprunorum—Pam (formerly Pseudomonas syringae pv. morsprunorum). Recently detected in Chile, Pam is known to cause lesions in the aerial parts of the plant, followed by more severe symptoms such as cankers and gummosis in the later stages of the disease. This study presents the design of PCR and LAMP detection methods for the specific and sensitive identification of Pseudomonas amygdali pv. morsprunorum (Pam) from cherry trees. Twelve Pseudomonas isolates were collected, sequenced, and later characterized by Multi-locus Sequence Analysis (MLSA) and Average Nucleotide Identity by blast (ANIb). Three of them (11116B2, S1 Pam, and S2 Pam) were identified as Pseudomonas amygdali pv. morsprunorum and were used to find specific genes through RAST server, by comparing their genome with that of other Pseudomonas, including isolates from other Pam strains. The effector gene HopAU1 was selected for the design of primers to be used for both techniques, evaluating sensitivity and specificity, and the ability to detect Pam directly from plant tissues. While the PCR detection limit was 100 pg of purified bacterial DNA per reaction, the LAMP assays were able to detect up to 1 fg of purified DNA per reaction. Similar results were observed using plant tissues, LAMP being more sensitive than PCR, including when using DNA extracted from infected plant tissues. Both detection methods were tested in the presence of 30 other bacterial genera, with LAMP being more sensitive than PCR.

Fractional calculus has played a significant role in modeling complex systems in disciplines such as mathematics, physics, biology, and engineering [...]

Bacterial canker caused by Pseudomonas syringae pv. syringae (Pss) is responsible for substantial loss to the production of sweet cherry in Chile. To date, the molecular mechanisms of the Pss–sweet cherry interaction and the disease-related genes in the plant are poorly understood. In order to gain insight into these aspects, a transcriptomic analysis of the sweet cherry cultivar ‘Lapins’ for differentially expressed genes (DEGs) in response to Pss inoculation was conducted. Three Pss strains, A1M3, A1M197, and 11116_b1, were inoculated in young twigs, and RNA was extracted from tissue samples at the inoculation site and distal sections. RNA sequencing and transcriptomic expression analysis revealed that the three strains induced different patterns of responses in local and distal tissues. In the local tissues, A1M3 triggered a much more extensive response than the other two strains, enriching DEGs especially involved in photosynthesis. In the distal tissues, the three strains triggered a comparable extent of responses, among which 11116_b1 induced a group of DEGs involved in defense responses. Furthermore, tissues from various inoculations exhibited an enrichment of DEGs related to carbohydrate metabolism, terpene metabolism, and cell wall biogenesis. This study opened doors to future research on the Pss–sweet cherry interaction, immunity responses, and disease control.

Reunião de depoimentos em homenagem ao pesquisador Jesús Martín-Barbero, realizados por Isabel Ferin Cunha, Margarita Ledo Andión, Manuel Pinto e Joseph Straubhaar.

The search for drought tolerant species or cultivars is important to address water scarcity caused by climate change in Mediterranean regions. The anisohydric–isohydric behavior concept has been widely used to describe stomatal regulation during drought, simply in terms of variation of minimal water potential (Ψmin) in relation to pre-dawn water potential (Ψpd). However, its simplicity has sometimes failed to deliver consistent results in describing a complex behavior that results from the coordination of several plant functional traits. While Prunus dulcis (almond) is known as a drought tolerant species, little information is available regarding consistent metrics to discriminate among cultivars or the mechanisms underlying drought tolerance in almond. Here we show a sequence of plant stomatal, hydraulic, and wilting responses to drought in almonds, and the main differences between anisohydric and isohydric cultivars. In a pot desiccation experiment we observed that stomatal closure in P. dulcis is not driven by loss in turgor or onset of xylem cavitation, but instead, occurs early in response to decreasing Ψmin that could be related to the protection of the integrity of the hydraulic system, independently of cultivar. Also, we report that anisohydric cultivars of P. dulcis are characterized by maximum stomatal conductance, lower water potentials for stomatal closure and turgor loss, and lower vulnerability to xylem cavitation, which are traits that correlated with metrics to discriminate anisohydric and isohydric behavior. Our results demonstrate that P. dulcis presents a strategy to avoid cavitation by closing stomata during the early stages of drought. Future research should also focus on below-ground hydraulic traits, which could trigger stomatal closure in almond.

La obra de Dulce Chacón, La voz dormida (2002), apareció en el panorama literario español visibilizando los testimonios de las mujeres presas durante la dictadura franquista. La ficción de la novela propone compensar el déficit de conocimientos históricos sobre ese período y exaltar el papel de la mujer en la lucha contra el régimen. Este estudio analiza algunos hechos históricos que aparecen en la obra de ficción y como la autora los utiliza como materia diegética para integrarlo en la memoria colectiva. El trabajo presenta aspectos de la lucha femenina contra los regímenes políticos y su papel en la recuperación de la memoria histórica.

Abstract In this paper we study a new class of functions, which we call (ω,c) $(\omega ,c)$-pseudo periodic functions. This collection includes pseudo periodic, pseudo anti-periodic, pseudo Bloch-periodic, and unbounded functions. We prove that the set conformed by these functions is a Banach space with a suitable norm. Furthermore, we show several properties of this class of functions as the convolution invariance. We present some examples and a composition result. As an application, we prove the existence and uniqueness of (ω,c) $(\omega ,c)$-pseudo periodic mild solutions to the first order abstract Cauchy problem on the real line. Also, we establish some sufficient conditions for the existence of positive (ω,c) $(\omega ,c)$-pseudo periodic solutions to the Lasota–Wazewska equation with unbounded oscillating production of red cells.

In this article we give some asymptotic formulae for impulsive differential system with piecewise constant argument of generalized type (abbreviated IDEPCAG). These formulae are based on certain integrability conditions, by means of a Gronwall-Bellman type inequality and the Banach's fixed point theorem. Also, we study the existence of an asymptotic equilibrium of nonlinear and semilinear IDEPCAG systems. We present examples that illustrate our the results.

Currently, people spend most of their time inside their homes. However, poor conditions in terms of comfort and quality of the indoor environment can pose high risks to the inhabitants’ health. Therefore, a good quality environment is essential, since, in addition to the hazards present in indoor air (e.g., particles, (S)VOCs, CO, radon and tobacco smoke), extreme temperatures, relative humidity levels, pests (e.g., mold, dust mites and bioaerosols), noise, airborne infectious agents (e.g., SARS-CoV-2) and contamination through water and soil can cause physical injuries, respiratory diseases, damage to multiple organ systems as well as harmful effects on the mental health of the occupants. Faced with this requirement, housing evaluation models were studied together with the main types of risk that could affect the health of the inhabitants, with the objective of proposing a new evaluation model for housing health and safety risks, fitted to the occupants, and especially suitable for Portuguese dwellings, although applicable in other geographical contexts. As a result of this analysis, this article proposes a new model for evaluating health and safety risks in housing, applicable in Portugal, supported by an inspection form and, as the main difference from the existing models, parameter measurements, providing complementary data for the evaluation. This model was created based on a set of functional and regulatory requirements that were identified for the healthy use of living spaces. Twenty-eight hazards were identified, and the respective risk factors were assessed using different processes and target demographics, including visual inspection, parameter measurements, occupants’ age and location and age of housing. In order to validate the model and determine its usefulness, it was applied to a set of houses with different construction dates, locations and occupants. This exercise enabled the identification of hazard classes and the calibration and fine tuning of the model application. Finally, proposals for future work are presented in order to create a base of evolution for the model.

The main aim of this survey article is to present several known results about vector-valued almost periodic functions and their applications. We separately consider almost periodic functions depending on one real variable and almost periodic functions depending on two or more real variables. We address several open problems and possibilities for further investigations of almost periodic functions, quoting more than two hundred references about the subject under our consideration.

In this paper we study a periodic impulsive Hopfield-type neural network system with piecewise constant argument of generalized type. Under general conditions, existence and uniqueness of solutions of such systems are established using ergodicity, Green functions and Gronwall integral inequality. Some sufficient conditions for the existence and stability of periodic solutions are shown and a new stability criterion based on linear approximation is proposed. Examples with constant and non-constant coefficients are simulated, illustrating the effectiveness of the results.

In this paper we study a new class of functions, which we call $(\omega,c)$-periodic functions. This collection includes periodic, anti-periodic, Bloch and unbounded functions. We prove that the set conformed by these functions is a Banach space with a suitable norm. Furthermore, we show several properties of this class of functions as the convolution invariance. We present some examples and a composition result. As an application, we establish some sufficient conditions for the existence and uniqueness of $(\omega,c)$-periodic mild solutions to a fractional evolution equation.

Abstract Background Patients with liver cirrhosis undergoing liver transplantation have a hyperdynamic circulation which persists into the early postoperative period making accurate assessment of fluid requirements challenging. Goal-directed fluid therapy (GDFT) has been shown to reduce morbidity and mortality in a number of surgery settings. The impact of GDFT in patients undergoing liver transplantation is unknown. A feasibility trial was designed to determine patient and clinician support for recruitment into a randomised controlled trial of GDFT following liver transplantation, adherence to a GDFT protocol, participant withdrawal, and to determine appropriate endpoints for a subsequent larger trial to evaluate the efficacy of GDFT in patients undergoing liver transplantation. Methods The Cardiac output Optimisation following Liver Transplant (COLT) trial is designed as a prospective, single-centre, randomised controlled study to assess the feasibility and safety of GDFT in liver transplantation for patients with cirrhosis. Consenting adults (aged between 18 and 80 years) with biopsy-proven liver cirrhosis who have been selected to undergo a first liver transplantation will be included in the trial and randomised into GDFT or standard care starting immediately after surgery and continuing for the first 12 h thereafter. Both groups will have cardiac output and stroke volume monitored using the FloTrac (EV1000) device. The intervention will consist of a protocolised GDFT approach to patient management, using stroke volume optimisation. The control group will receive standard care, without stroke volume and cardiac output measurement. After 12 h the patient’s fluid management will revert to standard of care. The primary endpoint of this study is feasibility. Secondary endpoints will include a safety assessment of the intervention, graft and patient survival, liver function, postoperative complications graded by Clavien-Dindo criteria, length of intensive care and hospital stay and quality of life across the intervention and control groups. Discussion There is a growing body of evidence that the use of perioperative GDFT in surgical patients can improve outcomes; however, signals of harm have also been detected. Patients with liver cirrhosis undergoing liver transplantation have markedly different cardiovascular physiology than general surgical patients. If GDFT is proven to be feasible and safe in this patient group, then a multicentre trial to demonstrate efficacy and cost-effectiveness will be required. Trial registration International Standard Randomised Controlled Trial Registry, ID: ISRCTN10329248. Registered on 4 April 2016.

En los últimos años, mucho se ha dicho sobre la importancia de la formación de profesores para promover la Educación para los medios en la escuela. Varios documentos han señalado su urgencia y varios estudios (por ejemplo Bujokas, 2015; Taye & Pérez-Tornero, 2012; UNESCO, 2011; Bazalgette, 2007) han llamado la atención sobre la necesidad de preparar a los docentes para enfrentar los desafíos de la era digital, explotando los recursos y oportunidades provistos por los medios y las redes de comunicación para enriquecer el desarrollo personal y social. La integración curricular y la formación de profesores en educación para los medios de comunicación siguen siendo, sin embargo, un gran desafío para el sistema educativo. En Portugal, el ‘Referencial de Educación para los Medios para la Educación Preescolar, la Enseñanza Básica y la Enseñanza Secundaria’, aprobado por el Ministerio de Educación en abril de 2014, puede representar un marco para la implementación de la Educación para los Medios en las escuelas. A partir de esta iniciativa, así como del proyecto europeo ‘e-MEL-e-Media Education Lab’, fueron promovidos por los autores de este artículo, en el año escolar 2015-2016, cuatro cursos de formación continua de profesores en régimen b-learning. Este artículo pretende presentar los resultados de estos cursos de formación, discutiendo las expectativas, las competencias desarrolladas y los obstáculos identificados por los profesores. Con base en esta experiencia de formación, se pretende también discutir los principios metodológicos y las modalidades de formación en Alfabetización en Medios. El artículo termina apuntando a la necesidad de una política educativa que valorice la formación de profesores, lo que podrá contribuir a una implementación consistente de la Educación para los Medios en las escuelas.

As a consequence of climate change, water scarcity has increased the use of the iso-/anisohydric concept with the aim of identifying anisohydric or drought-tolerant genotypes. Recently, Meinzer and colleagues developed a metric for discriminating between iso- and anisohydric behavior called the hydroscape, which describes a range in which stomata control leaf water potential (Ψ) with decreasing water availability, and it is linked to several water-regulation and drought-tolerance traits. Thus, our objective was to test the usefulness of the hydroscape in discriminating between iso- and anisohydric Prunus dulcis cultivars, a species that is widely cultivated in Mediterranean central Chile due to its ability to withstand water stress. Through a pot desiccation experiment, we determined that the hydroscape was able to discriminate between two contrasting Prunus cultivars; the more anisohydric cultivar had a hydroscape 4.5 times greater than that of the other cultivar, and the hydroscape correlated with other metrics of plant water-use strategies, such as the maximum range of daily Ψ variation and the Ψ at stomatal closure. Moreover, the photosynthesis rates were also differently affected between cultivars. The more isohydric cultivar, which had a smaller hydroscape, displayed a steeper photosynthesis reduction at progressively lower midday Ψ. This methodology could be further used to identify drought-tolerant anisohydric Prunus cultivars.

The broad distribution of quinoa in saline and non-saline environments is reflected in variations in the photosynthesis-associated mechanisms of different ecotypes. The aim of this study was to characterize the photosynthetic response to high salinity (0.4 M NaCl) of two contrasting Chilean genotypes, Amarilla (salt-tolerant, salares ecotype) and Hueque (salt-sensitive, coastal ecotype). Our results show that saline stress induced a significant decrease in the K+/Na+ ratio in roots and an increase in glycine betaine in leaves, particularly in the sensitive genotype (Hueque). Measurement of the photosynthesis-related parameters showed that maximum CO2 assimilation (Amax) in control plants was comparable between genotypes (ca. 9–10 μmol CO2 m−2 s−1). However, salt treatment produced different responses, with Amax values decreasing by 65.1% in the sensitive ecotype and 37.7% in the tolerant one. Although both genotypes maintained mesophyll conductance when stomatal restrictions were removed, the biochemical components of Amarilla were impaired to a lesser extent under salt stress conditions: for example, the maximum rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO; Vcmax) was not as affected in Amarilla, revealing that this enzyme has a higher affinity for its substrate in this genotype and, thus, a better carboxylation efficiency. The present results show that the higher salinity tolerance of Amarilla was also due to its ability to control non-diffusional components, indicating its superior photosynthetic capacity compared to Hueque, particularly under salt stress conditions.

This article deals with the asymptotic behavior of nonoscillatory solutions of fourth order linear differential equation where the coefficients are perturbations of linear constant coefficient equation. We define a change of variable and deduce that the new variable satisfies a third order nonlinear differential equation. We assume three hypotheses. The first hypothesis is related to the constant coefficients and set up that the characteristic polynomial associated with the fourth order linear equation has simple and real roots. The other two hypotheses are related to the behavior of the perturbation functions and establish asymptotic integral smallness conditions of the perturbations. Under these general hypotheses, we obtain four main results. The first two results are related to the application of a fixed point argument to prove that the nonlinear third order equation has a unique solution. The next result concerns with the asymptotic behavior of the solutions of the nonlinear third order equation. The fourth main theorem is introduced to establish the existence of a fundamental system of solutions and to precise the formulas for the asymptotic behavior of the linear fourth order differential equation. In addition, we present an example to show that the results introduced in this paper can be applied in situations where the assumptions of some classical theorems are not satisfied.

Nowadays, in Europe and the world, we experience the continued effervescence of mobility, dislocation, travels and comings and goings...

Vive-se hoje na Europa e no mundo a efervescência contínua da mobilidade, da deslocação, da viagem, da ida e do regresso...

This article deals with the asymptotic behavior of nonoscillatory solutions of fourth order linear differential equation where the coefficients are perturbations of constants. We define a change of variable and deduce that the new variable satisfies a third order nonlinear differential equation. We assume three hypotheses. The first hypothesis is related to the constant coefficients and set up that the characteristic polynomial associated with the fourth order linear equation has simple and real roots. The other two hypotheses are related to the behavior of the perturbation functions and establish asymptotic integral smallness conditions of the perturbations. Under these general hypotheses, we obtain four main results. The first two results are related to the application of a fixed point argument to prove that the nonlinear third order equation has a unique solution. The next result concerns with the asymptotic behavior of the solutions of the nonlinear third order equation. The fourth main theorem is introduced to establish the existence of a fundamental system of solutions and to precise the formulas for the asymptotic behavior of the linear fourth order differential equation. In addition, we present an example to show that the results introduced in this paper can be applied in situations where the assumptions of some classical theorems are not satisfied.

Drug decriminalization in Portugal is a failure, despite several published articles claiming exactly the opposite. This paper will show that there is an illogical campaign supporting the Portuguese drug policy and an unacceptable manipulation of factual information. A book written by Glenn Greenwald, a lawyer fluent in Portuguese, suggests the opposite of what the research data demonstrates. He claims that Portugal is a success. Mr. Greenwald is a member of the Cato Institute, an American libertarian think-tank that has been advocating for drug legalization for many years. This complex issue has been broadcast worldwide by the press, both Portuguese and international, boosting the proliferation of the ‘good news’ about the Portuguese drug policy and distorting the real analysis of what is going on in this country. This is happening to an extent that Anand Grover, the United Nations Special Rapporteur on the Right of Everyone to the Highest Attainable Standard of Physical and Mental Health, working in the area of drug dependence did invite the world to ‘reflect about human rights in drug use’ and ‘place health at the core of drug policy’. In their report, he highlighted two core issues, ‘health’ and ‘human rights.’ Could this be used to justify the approach of legalization of drugs, at any price? Have they laid down their arms and are dangerously opening the way to the medicalization of drug dependency? Surprisingly, the two recent 2010 and 2011 EMCDDA (European Monitoring Centre for Drugs and Drug Addiction Reports), which emphasized the use of substitution drugs as a main tool to tackle opioid dependence, show clearly that Europe looks eager to follow this path.Is this the right path?

This work concerns the existence of almost periodic solutions for certain differential equations with piecewise constant arguments. The coefficients of these equations are almost periodic and the equation can be seen as perturbations of a linear equation satisfying an exponential dichotomy on a difference equation. The stability of that solution on a semi-axis is also studied.

In this work, using discontinuous almost periodic type functions, exponential dichotomy and the notion of Bi-almost automorphicity we give sufficient conditions to obtain a unique almost automorphic solution of a quasilinear system of differential equations with piecewise constant arguments. Finally, an application to the Lasota–Wazewska model with piecewise constant delayed argument is given.

In this article we introduce a class of discontinuous almost automorphic functions which appears naturally in the study of almost automorphic solutions of differential equations with piecewise constant argument. Their fundamental properties are used to prove the almost automorphicity of bounded solutions of a system of differential equations with piecewise constant argument. Due to the strong discrete character of these equations, the existence of a unique discrete almost automorphic solution of a non-autonomous almost automorphic difference system is obtained, for which conditions of exponential dichotomy and discrete Bi-almost automorphicity are fundamental.

Despite the conceptual difficulties and complex configuration, the concept of public sphere has dominated much of the recent literature in areas such as political sciences, cultural studies, communication sciences and sociology of new media...

De difícil definição e complexa configuração, o conceito de esfera pública tem dominado grande parte da recente literatura em áreas como ciência política, estudos culturais, ciências da comunicação e sociologia dos novos media...

We study almost automorphic solutions of recurrence relations with values in a Banach space $V$ for quasilinear almost automorphic difference systems. Its linear part is a constant bounded linear operator $\varLambda$ defined on $V$ satisfying an exponential dichotomy. We study the existence of almost automorphic solutions of the non-homogeneous linear difference equation and to quasilinear difference equation. Assuming global Lipschitz type conditions, we obtain Massera type results for these abstract systems. The case where the eigenvalues $\lambda$ verify $\left|\lambda\right|=1$ is also treated. An application to differential equations with piecewise constant argument is given.

Professor de Ciências da Comunicação na Universidade Stendhal de Grenoble, Daniel Bougnoux...

A complexidade crescente da vida social, a proliferação das fontes e das formas de aceder, gerir e fazer circular a informação, as transformações no plano económico-social e no plano cultural e ético induzidas pelas inovações tecnológicas tornam necessário repensar o quadro em que ocorre a formação inicial e contínua dos profissionais da comunicação e, em especial, dos jornalistas. Neste texto, recorreu-se ao conceito de campo proposto por Bourdieu para sublinhar os dinamismos do campo jornalístico e as suas interacções com os restantes campos sociais, destacando os desafios, condicionantes, requisitos e orientações que as instituições de ensino superior que fazem formação de jornalistas não poderão deixar de equacionar. Sustenta-se a necessidade demanter uma permanente tensão entre o contacto e a familiarização com o terreno da prática profissional, por um lado, e com o distanciamento crítico que os instrumentos teóricos e metodológicos possibilitam, por outro lado.

Afirmar que o jornalismo está a mudar tornou-se quase uma banalidade, a ponto de o próprio discurso da mudança se repetir como evidência trauteada e, por conseguinte, obnubiladora da própria mudança que enuncia...

Facing strong competition and financial hardship, Public Service Broadcasting (PSB) operators are redefining their role and re-inventing new futures. The Portuguese PSB, Radiotelevisão Portuguesa (RTP) is no exception and important changes have recently been introduced in the traditional ‘public service’ model. The centre-right government – in office since 2002 with a qualified majority – perceived the restructuring of RTP as a major political goal and, in an unprecedented move, it has decided to hand out one RTP’s generalist channel to ‘civil society’. This article looks at this political decision and its financial and economic implications. It argues that as far as rhetoric went, citizens had the centre-stage in this new ‘participatory model’ but it is economics rather than citizenry that is at the very heart of this strategy.

Este número temático da revista Comunicação e Sociedade resulta do trabalho desenvolvido no âmbito da Conferência “A nova entidade reguladora no quadro das polí- ticas de comunicação em Portugal”, que teve lugar na Universidade do Minho no dia 10 de Abril de 2006...

Los periódicos, la televisión o internet son medios privilegiados al momento de la construcción, manutención o reconfiguración de identidades. No es casual entonces que muchos organismos o entidades se valgan de este tipo de medios como elementos centrales a la hora de construir sus textos multimodales en el desarrollo de su identidad o en la configuración de su imagen. Así, por ejemplo, estamentos gubernamentales levantan campañas multimediales con propósitos de afiliación, reconocimiento y hasta cohesión social dentro del contexto globalizado y mediatizado de este nuevo milenio. El Bicentenario es nuestro objetivo de análisis como núcleo de una campaña cuya finalidad comunicativa es la cohesión social, el reconocimiento de los chilenos y la posibilidad de, desde un discurso patriótico con cimientos históricos y una frescura universalizable, hacer encontrarse a los chilenos entre sí y de transmitirse como marca hacia el exterior a través de distintos recursos semióticos existentes, aprovechando soportes y medios de consumo masivo actuales para fortalecer una visión de partir con historia, presente y futuro. Por consiguiente, analizaremos los textos multimodales de la campaña, desde una perspectiva del estudio de la marca país, a partir del cuadro teórico de la semiótica social.

Se por noticiário televisivo entendermos um conjunto de peças organizadas de modo global, um alinhamento deverá sempre funcionar como um todo, apresentando uma evolução na continuidade. Se por alinhamento do telejornal concebermos a imagem de um continuum ao longo do qual as notícias passam de quentes a frias, de sérias a lúdicas, a primeira notícia, a de abertura, apresenta um particular interesse. Ela reflecte aquilo que de mais importante acontece no país e no mundo, integra-se num conjunto de que se espera uma certa coerência e assume-se como o mais significativo do noticiário: é a primeira. Neste artigo analisamos a abertura do Telejornal da RTP desde 1959 até 2009. Distinguimos nesse trabalho quatro períodos que nos parecem distintos na História da Televisão Portuguesa: 1) o Estado Novo; 2) o 25 de Abril; 3) os anos de democracia em regime de monopólio televisivo; e 4) o período pós-TV privadas. Através desta análise queremos conhecer aquilo que, em meio século, o mais antigo programa de informação considerou ser o mais relevante no país e no mundo e, através disso, perceber a evolução dos registos de noticiabilidade aí destacados, o que nos ajudará a compreender melhor a evolução do jornalismo televisivo.

In this paper we investigate the existence of the periodic solutions of a quasilinear differential equation with piecewise constant argument of generalized type. By using some fixed point theorems and some new analysis technique, sufficient conditions are obtained for the existence and uniqueness of periodic solutions of these systems. A new Gronwall type lemma is proved. Some examples concerning biological models as Lasota-Wazewska, Nicholson's blowflies and logistic models are treated.

By using the concept of integrable dichotomy, the fixed point theory, functional analysis methods and some new technique of analysis, we obtain new criteria for the existence and uniqueness of bounded and periodic solutions of general and periodic systems of nonlinear integro-differential equations with infinite delay.

Cidadania e Literacias Mediáticas é a temática central do presente número da revista Comunicação e Sociedade...

RESUMEN. El presente estudio tuvo por objetivo evaluar la influencia del uso de homogeneización de diferentes proporciones de leche - que permite aumentar rendimientos en el proceso y probablemente mejorar la calidad sensorial del producto - sobre la maduración del queso Chanco bajo en grasa.Se estudiaron 5 tratamientos (3 repeticiones), dos de los cuales fueron testigos (uno de grasa normal y otro bajo en grasa), los otros 3 tratamientos fueron: bajos en grasa, con leche parcialmente homogeneizada en concentraciones de 12.5; 25 y 50%, del volumen total de leche. Por metodología estandarizada se estudió la evolución de la maduración en términos de humedad, materia grasa, proteína, índice de maduración (NS/NT%), lipólisis (ADV), pH, calidad sensorial y microestructura del producto. Los tratamientos de baja grasa con leche homogeneizada presentaron menores pérdidas de grasa en el suero, consecuentemente los rendimientos aumentaron. El estudio permitió conocer el perfil de maduración del queso Chanco bajo en grasa, así, se observó que los tratamientos de baja grasa con homogeneización mostraron mayor lipólisis que el testigo de baja grasa sin homogeneizar, aun cuando fue menor que el tratamiento testigo de grasa normal, pero no se evidenció diferencias respecto a la proteólisis. Los tratamientos de baja grasa con leche homogenizada no mejoraron el sabor ni la firmeza de los quesos, probablemente debido al corto período de maduración normal de esta variedad (21 días), aunque el tratamiento 3 presentó ciertas ventajas que podrían potenciarse aplicando simultáneamente otras ayudas tecnológicas.SUMMARY. Maturation study of low fat Chanco cheese made with homogenized milk. The purpose of this study was to evaluate the influence the use of homogenization of different proportions of milk - which allow to increase the yield in the process and probably to improve sensorial characteristics of the cheese - has on the ripening of low fat Chanco cheese.Five treatments (three replicates each) were studied, two corresponded to control (normal fat and low fat) and the other three treatments were low fat using partially homogenized milk in the following percentages of the total volume of milk; 12.5, 25 and 50%.Standard methodology was used to monitor the evolution of ripening in terms of moisture, fat and total protein content, ripening index (NS/NT%), lipolysis (ADV), pH, sensorial quality and micro structure of the product. The low fat treatments with homogenized milk showed less fat losses in the whey and consequently increased yields. This study allowed us to know the low fat Chanco cheese maturation profile, low fat treatments with homogenisation showed a higher degree of lipolysis than the non - homogenized low-fat control although it was lower than normal fat control. No differences in terms of the development of proteolysis were observed. The low - fat homogenized treatments did not show improvement in the flavor neither in the cheese firmness probably due to the short ripening period (21 days) of this cheese variety, nevertheless T3 presented some advantages which could be improved applying simultaneously another technological helps.

Ante a crescente complexidade dos fenômenos sociais e das opções sobre as quais devemos decidir, ante a avalancha informativa que os novos e os velhos meios de comunicação e informação põem à nossa disposição, ante as mensagens mais díspares que, de vários lados, tentam seduzir e convencer, resulta verdadeiramente urgente redefinir o conceito de cidadania, redescobrir os campos e as dimensões implicadas nele, ensaiar novos modos de aprender a viver, individual e coletivamente nos novos cenários que estão se desenhando, com a preocupação de reequilibrar o papel e a missão da escola. Apesar de existir consenso de que uma prática democrática da cidadania encontra o perfeito campo para seu exercício na relação crítica com os meios, nos países que sofreram a experiência de regimes autoritários – e que possuem uma experiência democrática ainda insuficiente entretecida nas práticas cotidianas – resulta difícil conquistar um espaço para a educação para os meios. Esse é o caso de Portugal, onde ainda se tem um conhecimento parcial e fragmentário das experiências realizadas neste campo. Ainda que tais experiências não constituíram verdadeiras políticas na matéria, existem sinais que estariam dando conta das mudanças e das inquietações que têm lugar, especialmente no âmbito das escolas e dos mestres e professores que lideram essas iniciativas. Se entendemos a educação para os meios em sua relação com os processos socioculturais e de mudança social, devemos vinculá-la com as características mais notáveis dos mesmos: aceleração da vida social, enfatização da cultura do presente, deslocalização, alteração da noção de escala e crise das grandes narrativas que davam sentido à ação humana e à História. Por outro lado, se a compreendemos como educação para a comunicação e para a cidadania, é necessário, antes de tudo, que se estabeleça um novo e adequado paradigma pedagógico que se apóie na relação entre a teoria e a prática, e que chegue aos centros de formação de professores.