Journal articles on the topic 'Polarisation manipulation'

Optical properties of metal nanostructures, governed by the so-called localised surface plasmon resonance (LSPR) effects, have invoked intensive investigations in recent times owing to their fundamental nature and potential applications. LSPR scattering from metal nanostructures is expected to show the symmetry of the oscillation mode and the particle shape. Therefore, information on the polarisation properties of the LSPR scattering is crucial for identifying different oscillation modes within one particle and to distinguish differently shaped particles within one sample. On the contrary, the polarisation state of light itself can be arbitrarily manipulated by the inverse designed sample, known as metamaterials. Apart from polarisation state, external stimulus, e.g., magnetic field also controls the LSPR scattering from plasmonic nanostructures, giving rise to a new field of magneto-plasmonics. In this review, we pay special attention to polarisation and its effect in three contrasting aspects. First, tailoring between LSPR scattering and symmetry of plasmonic nanostructures, secondly, manipulating polarisation state through metamaterials and lastly, polarisation modulation in magneto-plasmonics. Finally, we will review recent progress in applications of plasmonic and magneto-plasmonic nanostructures and metamaterials in various fields.

Background: This paper presents a fundamental study of protein manipulation under the influence of dielectrophoretic (DEP) force for a lab-on-a-chip platform. Objective: Protein manipulation is dependent on the polarisation factor of protein when exposed to an electric field. Therefore the objective of this work is a microfluidic device and measurement system are used to characterise the human beta-2 microglobulin (β2M) protein via lateral attractive forces and vertical repulsive forces by means of DEP responses. Method: The manipulation of the β2M protein was conducted using a microfluidic platform with a tapered DEP microelectrode and the protein concentration was quantified based on a biochemical interaction using an Enzyme-Linked Immunosolvent Assay (ELISA). The protein distribution has been analysed based on the β2M concentration for each microfluidic outlet. Results: At 300 kHz, the protein experienced a negative DEP (nDEP) with of 83.3% protein distribution on the middle microchannel. In contrast, the protein experienced a positive DEP (pDEP) at 1.2 MHz with of 78.7% of protein on the left and right sides of the microchannel. Conclusion: This is concept proved that the tapered DEP microelectrode is capable of manipulating a β2M via particle polarisation, hence making it suitable to be utilised for purifying proteins in biomedical application.

Manipulation is a kind of speech activity which has definite intentions and aims, such as gaining control and power within political discourse. This paper will shed light on the theoretical ground on which this phenomenon is based to determine how language is utilized for manipulation. The analysis aims to investigate manipulative strategies and the language devices used in generating these strategies in al-Gaddafi s speech known as Zenga. Also, it will pay more attention to strategy of polarisation, i.e. basic strategy of positive self-presentation and negative other-presentation. This paper will be limited to lexical-semantic devices (selection of negative words for them and positive words for us), certain grammatical mechanisms (passive, nominalisation) and rhetorical devices (metaphor, metonymy, hyperbole). The study shows the diversity of modes of how language of the speech is manipulated on diffe ent levels of discourse.

This study presents the particular discursive strategies used by some Arabic newspapers to serve the Islamist fundamentalists’ goals and strengthen their hegemonic ideology in the Middle East. It also describes the move to create and sustain a new wave of Occidentalism, the doctrine of negatively representing the West, a counterpart to Edward Said’s Orientalism, the doctrine of negatively representing the East. Occidentalism is a retaliatory ideological strategy that rebuffs hegemonic Western ideas; it is used by some chauvinistic Arabs trying to create a distorted image of the West in the minds of Middle Easterners. In this paper, I will investigate the negative side of the concept of Occidentalism, as exploited by today’s fanatics in their justification for attacking the West. Some Arabic newspapers contribute to fanaticism through antagonistic rhetoric that glorifies Pan-Arab brotherhood, chauvinistic Arab nationalism, and martyrdom. By glorifying these demagogic mottoes, such newspapers create an ideological polarisation against the West, in that they try to win their readers’ sympathy, control their emotions, and deepen their nostalgic feelings for the great Arab past.

Discussing the topic of the capability of dielectrophoresis (DEP) devices in terms of the selective detection and rapid manipulation of particles based on the DEP force (FDEP) via contactless methods is challenging in medical research, drug discovery and delivery. Nonetheless, the process of the selective detection and rapid manipulation of particles via contactless DEP based on dielectric particles and the surrounding medium can reduce the effects of major issues, including physical contact with the particles and medium contamination to overcome operational difficulties. In this review, DEP microelectromechanical system (MEMS) microelectrodes with a tapered profile for the selective detection and rapid manipulation of particles were studied and compared with those of conventional designs with a straight-cut profile. The main objective of this manuscript is to review the versatile mechanism of tapered DEP MEMS microelectrodes for the purpose of selective detection and rapid manipulation. Thus, this review provides a versatile filtration mechanism with the potential for a glomerular-based membrane in an artificial kidneys’ development solution for implementing engineered particles and cells by lateral attraction as well as vertical repulsion in the development of lab-on-a-chip applications. For tapered DEP MEMS microelectrodes, the scope of this study methodology involved the characterisation of DEP, modelling of the polarisation factor and the dynamic dielectric changes between the particles and medium. Comprehensive discussions are presented on the capability of tapered DEP microelectrodes to drive the selected particles and the simulation, fabrication and testing of the tapered profile. This study revealed an outstanding performance with the capability of producing two regions of high electric field intensity at the bottom and top edges of the side wall of tapered microelectrodes. Observations on particle separation mainly by the lateral attraction force of particles with positive DEP on the y-axis and vertical repulsion force of particles with negative DEP on the z-axis proved an efficient and uniform FDEP produced by tapered electrodes. In conclusion, this study confirmed the reliability and efficiency of the tapered DEP microelectrodes in the process of selective detection and rapid manipulation at a higher efficiency rate than straight-cut microelectrodes, which is significant in DEP technology applications.

Dynamic phase modulation is vital for tuneable focusing, beaming, polarisation conversion and holography. However, it remains challenging to achieve full 360° dynamic phase modulation while maintaining high reflectance or transmittance based on metamaterials or metasurfaces in the terahertz regime. Here, we propose a doubly resonant graphene–metal hybrid metasurface to address this challenge. Simulation results show that by varying the graphene Fermi energy, the proposed metasurface with two shifting resonances is capable of providing dynamic phase modulation covering a range of 361° while maintaining relatively high reflectance above 20% at 1.05 THz. Based on the phase profile design, dynamically tuneable beam steering and focusing were numerically demonstrated. We expect that this work will advance the engineering of graphene metasurfaces for the dynamic manipulation of terahertz waves.

Ali Smith’s seasonal quartet—Autumn, Winter, Spring, Summer—was written and published at lightning speed, between the 2016 Brexit referendum and Britain’s effective departure from the EU in 2020. The article examines how the novels engage with the issue of Brexit, as they become the chronicle of a grinding cultural process and critically confront the transformation of the British nation. I survey various psychological factors related to the polarisation of the British nation and investigate Smith’s presentation of the way in which the populist propaganda of menace produced by the right-wing media leads to marginalising Otherness. Employing the nomadic theory of the subject developed by Rosi Braidotti, I analyse Smith’s literary strategies used to represent not only post-truth manipulation and institutionalised British xenophobia, but also the actions of people who resist them.

A historical analysis of the regulation of propaganda and obligations on States to prevent its dissemination reveals competing origins of the protection (and suppression) of free expression in international law. The conflict between the ‘marketplace of ideas’ approach favoured by Western democracies and the Soviet Union's proposed direct control of media outlets have indirectly contributed to both the fake-news crisis and engineered polarisation via computational propaganda. From the troubled League of Nations to the Friendly Relations Declaration of 1970, several international agreements and resolutions limit State use of propaganda to interfere with ‘malicious intent’ in the affairs of another. Yet State and non-State actors continually use a variety of methods to disseminate deceptive content sowing civil discord and damaging democracies in the process. In Europe, much of the discourse about the regulation of ‘fake news’ has revolved around the role of the European Union's General Data Protection Regulation and the role of platforms in preventing ‘online manipulation’. There is also a common perception that human rights frameworks limit States' ability to constrain political speech; however, using the principle of subsidiarity as a mapping tool, a regulatory anomaly is revealed. There is a significant lack of regulatory oversight of actors responsible for, and the flow of, computational propaganda that is disseminated as deceptive political advertising. The article examines whether there is a right to disseminate propaganda within our free expression rights and focuses on the harms associated with the engineered polarisation that is often the objective of a computational propaganda campaign. The article concludes with a discussion of the implications of maintaining this status quo and some suggestions for plugging the regulatory holes identified.

Ethnic politics will continue to be a more significant challenge in the twenty-first century for a large number of African countries. Many scholars believe that creating ethnic-based political ideologies in the mainstream will make it more difficult for the masses to have representation. Ethnic politics could be an appealing tool for leaders seeking to preserve power through appeals to emotion and manipulation of resources, with no added value or rational debate. Political stability and democratic ideas are contingent on how African politicians respond to ethnic and language-based politics in the future. The challenge is finding a way to reconcile economic growth and well-being with entitlement politics. This article examines the rise of ethnic politics in Africa through the lens of six African countries. The article's question is how political, ideological polarisation can be avoided in Africa, and a win-win strategy to that end is being explored. The article also attempts to convey a comprehensive perspective on shaping political debates to understand the foundations of political elites and parties.

The article critically examines the assumption implicit in the research on social solidarity and popular attitudes that institutional solidarity equates with mutual care in society. Following a review of a selection of recent empirical research on social solidarity and popular attitudes to welfare it is concluded that the evidence points to general support for welfare based on self-interest and the principle of mutual insurance rather than social altruism. The analysis proceeds by arguing that social and economic changes which have resulted in social polarisation have weakened ‘functional democracy’ (the reciprocal dependency of one social group or class on another) leading to possible ‘decivilising tendencies’ and a decline in mutual empathy. The article argues that post-emotionalism may be the result of these processes: the breakdown in mutual knowledge across the class divide; the intellectualisation of feelings; interaction based on false ‘niceness’; the manipulation of emotions. The paper concludes by suggesting that post-emotional attitudes are the by-product of government social steering towards amoral familism in social policy through the provision of a ‘vocabulary of motives’ which are negative to state welfare.

The interference control measured in the Emotional Stroop Task is the phenomenon that gives us an insight into mechanisms of emotion-cognition interactions. Especially the role of dimensions of affect can be easily studied with this paradigm. In the current study, we were interested in the role of the complexity of emotional stimuli (origin). We also aimed at searching for activation-like factors that impair (arousal) or improve (subjective significance) the effectiveness of cognitive control. We have used an orthogonal manipulation of all the above dimensions in words. We expected to find the contrastive effects of arousal and subjective significance on reaction times and Event Related Potential’s amplitudes. On a behavioural level, we observed the reduction of reaction times with increasing subjective significance of stimuli and reflective origin. We also found a correlation between subjective significance and reduction of amplitude polarisation in the N450 component associated with cognitive control execution effort. This experiment shows that subjective significance has an improving role for cognitive control effectiveness, even when valence, arousal and origin levels are controlled. This guides us to conclude that external stimuli may drive not only disruption of control but also its improvement.

Animal experiments are very important for the development of new assisted reproductive techniques (ART) for use in human and animal reproductive medicine. Most technical aspects of reproductive manipulation of humans and animals are very similar, and many components of successful human ART used nowadays have been derived from animal studies. In this study we examined (1) the use of 'non-contact' laser for assisted hatching, (2) whether spindles in living mouse oocytes could safely be imaged/examined by polarisation microscope (polscope) and (3) the influence of environment (e.g. temperature, in vitro culture, etc.) on spindle detection/visualisation. The data of the study presented here show that (1) laser assisted hatching (AH) is a fast, very accurate and safe procedure without any harmful effect on embryo development and it can support very effectively the implantation of embryos, (2) the use of polscope facilitates the evaluation of oocyte quality and the selection of oocytes with spindle, (3) by monitoring the spindle position during intracytoplasmic sperm injection (ICSI), we can reduce spindle damage and increase the chance of fertilisation. Further studies are underway to test the hypothesised connection between spindle birefringence and developmental capacity of oocytes/embryos.

Ethnicity is a turbulent factor in Malaysian politics and society. Through decades of inter-ethnic tension fostered by ideological engineering, itself building on a history of ethnic manipulation and polarisation in colonial times, racialised tension has remained at best dormant and at worst prone to erupt in riots reminiscent of the May 1969 riots. This study examines the discourse of ethnicity from Malaysia’s colonial roots up to the mid-20th century and beyond, seeking to highlight how trauma and struggle were integral to the very formation of ethnic consciousness. This work will also explore how, despite numerous writers questioning the naive “essentialising” of ethnicity, they no less mistakenly perceive ethnicity in terms which reduce it to a de-centred hybridised performance. The works of writers like Colin Abraham, Sumit Mandal and Maznah Mohamad will be surveyed to elucidate the traumatic element inherent to ethnicity itself. A Lacanian psychoanalytical framework will be used to argue, with a special focus on the Malays, that ethnic solidarity should rather be grounded in a constructive primordial frustration, i.e., it is a traumatic anti-essence which will ignite solidarity and a mutual longing for democracy among the various ethnic groups. Ontological trauma—not a universal essence, not cultural particulars, not deconstructed performatives and certainly not political ideology—could be the force that compels Malaysia’s volatile ethnic groups to co-exist and work together in nation-building.

DOI 10.24917/20837275.9.4.4Celem artykułu jest ukazanie problematyki wizualizacji danych w kontekście komunikacyjnym. Infografika staje się dziś za sprawą dziennikarstwa danych i popularności mediów wizualnych narzędziem powszechnie stosowanym; nie do końca rozpoznane są jednak właściwości manipulacyjne projektowania graficznego, które przedstawiane jest odbiorcom jako ilustrujące, tłumaczące i wyjaśniające treści statystyczne oraz tekstowe w sposób systemowy, uporządkowany i wizualny, co konotuje prostotę i uniwersalność oraz obiektywizm. Autorka stara się wykazać, jak idealistyczne teorie z zakresu projektowania informacji rzutują na proces nadawczo-odbiorczy (z jednej strony dając przestrzeń na manipulację danymi, z drugiej – tworząc idealny obraz projektanta jako strażnika obiektywizmu i posiadacza kompetencji interpretatora, wyzwalają tym samym bezbronność odbiorców w dekodowaniu języka wizualizacji danych i pozbawiają ich czujności, należnej przekazom perswazyjnym). Tymczasem, przekaz graficzny ma charakter nie tylko edukacyjny, ale też często polityczny czy szerzej – ideologiczny. Analiza przekazów graficznych zamieszczonych w portalu Visualizing Palestine (wybranego ze względu na globalny zasięg i popularność, polaryzację polityczną odbiorców oraz nowatorski, partycypacyjny i społecznościowy charakter procesu projektowego), służy tu przedstawieniu technik wizualizacji jako interpretacji i manipulacji danymi, a także potwierdza moc dyskursywną infografiki jako narzędzi komunikacyjnych. Artykuł ma na celu zwrócenie uwagi na problem powszechnego braku kompetencji w zakresie dekodowania znaczeń zawartych w wizualizacjach danych (datavis) oraz celowej (lub nie) nonszalancji projektantów w kwestii podejścia do danych.The Dataspace: Between Information Design and Data Manipulation. The Analysis of Specificity of Infographic Messages Based on Case Study of Visualising PalestineThe goal of the paper is to present the issues concerning data visualisation in communication context. Infographics nowadays becomes – due to data journalism and popularity of visual media – a commonly used tool; but still little recognition is given towards manipulatory features of graphic design which is presented to its recipients as illustrating, translating and explaining statistical and textual content in systemic, ordered and visual way that connotes simplicity, universality and objectivity. The author tries to prove that idealistic information design theories impact the communication process (on one hand giving the space for data manipulation, on the other – creating an ideal image of a designer seen as a guard of objectivism and an owner of an interpreter’s competences, thus they evoke recipients’ vulnerability in decoding the language of data visualisation and deprive them of awareness, which they should devote to persuasive messages). Whereas graphic message is not only of an educational nature but also often of a political or – widely speaking – an ideological one. The goal of the analysis of infographics published at the Visualizing Palestine website (chosen for its global range and popularity, as well as for the political polarisation of its recipients and for innovative, participative and grassroot character of the design process) is to indicate the technics of visualisation as interpretation and also data manipulation, as well as to prove the discoursive potential of infographics as a communication tool. The paper aims at drawing attention to the common lack of competences in the range of decoding meanings of datavis and the nonchalance (whether conscious or not) of designers in their usage of data.

Purpose The purpose of the paper is to reflect on the conditions of referenda as an EU input legitimacy, on the era of social media microtargeting campaigns. Taking the case of Brexit as an example, it takes conclusions for the democracy as an inherent value of the EU multilevel polity and opens prospects for possible solutions. Design/methodology/approach The paper is interdisciplinary based, complementing political science approaches on EU democratic legitimacy and communication studies on social media and political communication. These are the theoretical frameworks for analysing the case of Brexit referendum campaign, which is based on an empirical tracing of strategies and contents used. This empirical assessment is supported by official reports of the House of Commons and of the UK Information Commissioner’s Office and media news on the case. Analysis and discussion of it allows to come to conclusions. Findings Primary finding is that manipulation and disinformation occurred in Brexit campaign, creating a biased, fake and unbalanced information. Second main finding is that microtargeting and suppression of public debate enhances the typical polarisation of binary options on a referendum, and in the case of Brexit deepened the social cleavage that already shaped voter’s preferences, once information consumed by citizens functioned as “eco-chambers”, strengthening preconceptions. The ultimate conclusion in this case is a sign that social media can deepen the historical gap between elites and voters in the EU, with negative consequences for democracy and social legitimacy of the EU political system. Research limitations/implications The almost impossible access to the digital microtargeted adverts used in campaigns, to allow a more detailed analysis of the EU content issued. Practical implications Conclusions of this research are useful for politicians and advisers of policy-making to reflect on the future of the political system of the EU in terms of democracy, and the Europe as a whole and think about measures to be taken either on the level of improving legitimacy processes or regulation of digital media. Social implications If practical implications are taken from conclusions of this study, enhancing democratic processes, avoiding privacy data manipulation and providing accurate, impartial and trustworthy information to citizens public can be a social benefit achieved mainly through regulation. Originality/value Despite some studies have been released on Brexit referendum, they have mainly been single-disciplinary. This study innovates because it conciliates political science theoretical views with communications studies’ ones, to produce strengthened reasoning ground on the purposed of this research: to search evidence that new political communication strategies within the social media landscape can be of special negative influence in EU referenda and for the future of the multilevel polity.

Abstract Extraordinary optical transmission and good focusing properties of a two-dimensional scattering structure is presented. The structure is made of Fresnel zone plates periodically arranged along two orthogonal directions. Each plate consists of two ring-shaped waveguides supporting modes that match the symmetry of a circularly polarized incident plane wave. High field concentration at the focal plane is obtained with the short transverse and long longitudinal foci diameters. Optical vortex excitation in a paraxial region of the transmitted field is also observed and analysed in terms of cross-polarisation coupling. The structure presented may appear useful in visualization, trapping and precise manipulations of nanoparticles.

This paper analyses evaluative adjectives in George Ridpath’s political writings during the War of the Spanish Succession (1710-1713), in a corpus which comprises two journals, four years and 291 numbers, with the purpose of examining how this author used language as a weapon to shape and manipulate Great Britain’s public opinion during the Stuart period. For that, I have employed Wilson’s approach to Political Discourse Analysis (2001) and van Dijk’s polarisation (1999) as well as Allan and Burridge’s understanding of euphemism and dysphemism (1991). The results permit to value Ridpath’s contribution as a very influential but controversial pamphleteer who wrote about the War of the Spanish Succession within Great Britain’s context.

Ion traps are a promising platform for the realisation of high-performance quantum computers. To enable the future scalability of these systems, integrated photonic solutions for guiding and manipulating the laser light at chip level are a major step. Such passive optical components offer the great advantage of providing beam radii in the μm range at the location of the ions without increasing the number of bulk optics. Different wavelengths, from UV to NIR, as well as laser beam properties, such as angle or polarisation, are required for different cooling and readout processes of ions. We present simulation results for different optical photonic components, such as grating outcouplers or waveguide splitters and their applications on ion trap chips. Furthermore, we will introduce the experimental setup for the optical characterisation of the fabricated structures.

Iron and iron-phosphorus open-cell foams were tested for their potential use as synthetic bone graft substitutes. The samples were manufactured using a replica method based on a powder metallurgical approach. Iron foams alloyed with 0.5 wt. % of phosphorus were prepared with the aim of enhancing the mechanical properties and manipulating the corrosion rate. The manufactured foams were tested for their microstructure, porosity, corrosion behaviour and mechanical properties. SEM analyses of the foams’ microstructures confirmed the presence of an open, three-dimensional interconnected macroporous network similar to that of the human bone. The corrosion behaviour was studied by a static immersion test and potentiodynamic polarisation in Hank’s solution. The results showed that the presence of phosphorus slightly decreased the corrosion rate as compared to pure iron foams. The mechanical properties studied by a compression test confirmed a positive effect of phosphorus on the mechanical properties of the manufactured foams.

Piezoelectric actuators and sensors are applied in many fields in order to produce forces or displacements with the aim of sensing, manipulating or measurement, among other functions. This study presents the numerical methodology to optimize the static response of a thick-shell structure consisting of piezoelectric sensors, based on the maximisation of the electric charge while controlling the amount of piezoelectric and material required. Two characteristic functions are involved, determining the topology of the sensor and the polarisation profile. Constraints over the reaction force are included in the optimisation problem in order to avoid singularities. The topology optimisation method is used to obtain the optimal results, where regularisation techniques (density filtering and projection) are used to avoid hinges. The minimum length scale can be controlled by the use of three different projections. As the main novelty, a displacement-controlled scheme is proposed in order to generate a robust algorithm for future studies including non-linearities.

Abstract This article seeks to shed more light on Ukraine’s parliamentary elections by considering campaign tools that were derived from values in the electorate and used in elections between 2006 and 2012. The influence of political values on the electoral process was pointed out by American political scientists in the mid-20th century. My research demonstrates, however, that the political choices of Ukrainians in the 2006–2012 elections gave rise to campaign techniques that were not based on “classic” political values like freedom, human rights and democracy. Instead, their source was national identity-related values including the importance of a common history, culture and language along with religious and geopolitical preferences. These values differed between the western and central regions of Ukraine on the one hand and the southern and eastern parts of the state on the other. This regional polarisation did not seem very dangerous, however, until the emergence of election campaigns based on political ideology. As ideology gradually lost its mobilising potential, there was a need for an effective new system of political influence. Manipulative techniques were deployed to incite artificial clashes between citizens with different political identities. This article analyses specific uses of these techniques and uncovers links between their application and the destruction of the electoral space in Ukraine as well as the division of the country’s real political arena.

Background and Purpose: Social Networking Services (SNS), especially Twitter, have been an increasingly popular communication medium, especially in political transformation. This research analyses the language of tweets by Director General Inter-Services Public Relations (DG ISPR) of Pakistan, shared during the recent standoff between India and Pakistan on the issue of the Pulwama Attack in February 2019 and the Revocation of Article 370 by the Indian Government in August 2019. Methodology: The present research examines the linguistic techniques, and micro and macro approaches used in the discourse of tweets by DG ISPR on the said issues. Selection of vocabulary, tone of the message, and emotion in the discourse are studied through Ideological Square Model under the umbrella of CDA, with the aid of NVivo 12 Plus, to inspect the magnitude of the impact of linguistic memorandums from authoritative institutes. Findings: This study has revealed that the impeccable choice of vocabulary by ISPR adequately represented the Military of Pakistan, nationally and internationally, and has brought a state of tranquility at the time of standoff between two rival countries. This research argues that the discourse in tweets by DG ISPR represented Pakistan as a peaceful country but determinedly ready to defend its homeland during external enmity. Contributions: This study contributes a better understanding of the subtle ways in which language plays an essential role in creating political polarisation and constructing or manipulating reality while consolidating power struggle, discrimination, prejudice and inequality in society. Key Words: Pakistan military, Kashmir, ISPR, tweets, CDA, Ideological Square Mode. Cite as: Ashraf, R., Hassan Khan, M., Qazalbash, F., & Rahamad, M. S. (2022). Indo-Pak standoff 2019: A critical discourse analysis of selected tweets from inter-services public relations. Journal of Nusantara Studies, 7(2), 314-335. http://dx.doi.org/10.24200/jonus.vol7iss2pp314-335

Abstract Complex vector light fields have become a topic of late due to their exotic features, such as their non-homogeneous transverse polarisation distributions and the non-separable coupling between their spatial and polarisation degrees of freedom (DoF). In general, vector beams propagate in free space along straight lines, being the Airy-vector vortex beams the only known exception. Here, we introduce a new family of vector beams that exhibit novel properties that have not been observed before, such as their ability to freely accelerate along parabolic trajectories. In addition, their transverse polarisation distribution only contains polarisation states oriented at exactly the same angle but with different ellipticity. We anticipate that these novel vector beams might not only find applications in fields such as optical manipulation, microscopy or laser material processing but also extend to others.

BackgroundTissue factor (TF) generates proteases that can signal through PAR-1 and PAR-2. We have previously demonstrated PAR-1 signalling primes innate myeloid cells to be exquisitely sensitive to interferon-gamma (IFNγ). In this work we explored how TF mediated PAR-2 signalling modulated responsiveness to IFNγ and investigated the interplay between PAR-1/-2 signalling on macrophages.MethodologyWe characterised how TF through PAR-2 influenced IFNγ sensitivity in vitro using PCR and flow cytometry. and how it influenced oxazolone-induced delayed type hypersensitivity (DTH) responses in vivo. We investigated how basal signalling through PAR-2 influenced PAR-1 signalling using a combination of TF-inhibitors and PAR-1 &-2 agonists and antagonists. Finally, we investigated whether this system could be targeted therapeutically using 3-mercaptopropionyl-F-Cha-Cha-RKPNDK (3-MP), which has actions on both PAR-1 and -2.ResultsTF delivered a basal signal through PAR-2 that upregulated SOCS3 expression and blunted M1 polarisation after IFNγ stimulation, opposing the priming achieved by signalling through PAR-1. PAR-1 and -2 agonists or antagonists could be used in combination to modify this basal signal in vitro and in vivo. 3-MP, by virtue of its PAR-2 agonist properties was superior to agents with only PAR-1 antagonist properties at reducing M1 polarisation induced by IFNγ and suppressing DTH. Tethering a myristoyl electrostatic switch almost completely abolished the DTH response.ConclusionsTF-mediated signalling through PARs-1 and -2 act in a homeostatic way to determine how myeloid cells respond to IFNγ. 3-MP, an agent that simultaneously inhibits PAR-1 whilst delivering a PAR-2 signal, can almost completely abolish immune responses dependent on M1 polarisation, particularly if potency is enhanced by targeting to cell membranes; this has potential therapeutic potential in multiple diseases.

AbstractCold spots are sub-wavelength regions which might emerge near a nanoantenna, should one or more components of some far-field illumination cancel out with scattered light. We show that by changing only the polarisation, amplitude, and phase of two plane waves, a unique, zero-magnitude and highly sub-wavelength cold spot can be created and moved anywhere in the space around a nanoantenna of any arbitrary shape. This can be achieved using ultra-fast modulated pulses, or a time-harmonic approximation. Easily disturbed by a change in the nanoantenna’s material or position, a manufactured cold spot is fragile and could be used in nanoscale sensing. Our technique exploits the linearity of Maxwell’s equations and could be adapted to manipulate any phenomena governed by the linear wave equation, including acoustic scattering. This is a means for potentially ultra-fast sub-wavelength electric field manipulation.

Abstract Complex vector modes of light, non-separable in their spatial and polarisation degrees of freedom, are revolutionising a wide variety of research fields. It is therefore not surprising that the generation techniques have evolved quite dramatically since their inception. At present it is common to use computer-controlled devices, among which digital micromirror devices have become popular. Some of the reason for this are their low-cost, their polarisation-insensitive and their high-refresh rates. As such, in this manuscript we put forward a novel technique characterised by its high stability, which is achieved through a common-path interferometer. We demonstrate the capabilities of this technique experimentally, first by generating arbitrary vector modes on a higher-order Poincar\'e sphere, secondly, by generating vector modes in different coordinates systems and finally, by generating various vector modes simultaneously. Our technique will find applications in fields such as optical manipulations, optical communications, optical metrology, among others.

Abstract Manipulating symmetry environments of metal ions to control functional properties is a fundamental concept of chemistry. For example, lattice strain enables control of symmetry in solids through a change in the nuclear positions surrounding a metal centre. Light–matter interactions can also induce strain but providing dynamic symmetry control is restricted to specific materials under intense laser illumination. Here, we show how effective chemical symmetry can be tuned by creating a symmetry-breaking rotational bulk polarisation in the electronic charge distribution surrounding a metal centre, which we term a meta-crystal field. The effect arises from an interface-mediated transfer of optical spin from a chiral light beam to produce an electronic torque that replicates the effect of strain created by high pressures. Since the phenomenon does not rely on a physical rearrangement of nuclear positions, material constraints are lifted, thus providing a generic and fully reversible method of manipulating effective symmetry in solids.

Abstract Quantum entanglement is an integral part of quantum optics and has been exploited in areas such as computation, cryptography and metrology. The entanglement between photons can be present in various degrees of freedom (DOFs), and even the simplest bi-partite systems can occupy a large Hilbert space. Therefore, it is desirable to exploit this multi-dimensional space for various quantum applications by fully controlling the properties of the entangled photons in multiple DOFs. While current entangled-photon sources are capable of generating entanglement in one or more DOFs, there is currently a lack of practical techniques that can shape and control the entanglement properties in multiple DOFs. Here we show that cascading two or more entangled-photon sources with tunable linear media in between allows us to generate photon-pairs whose entanglement properties can be tailored and shaped in the frequency and polarisation domains. We first develop a quantum mechanical model to study the quantum state generated from the cascade structure with special considerations paid to the effects of pump temporal coherence, linear dispersion, and in-structure polarisation transformation applied between the entangled-photon sources. We then experimentally generate photon-pairs with tunable entanglement properties by manipulating the dispersion and birefringence properties of the linear medium placed in between two entangled-photon sources. This is done in an all-fibre, phase stable, and alignment-free configuration. Our results show that the cascade structure offers a great deal of flexibility in tuning the properties of entangled photons in multiple DOFs, opening up a new avenue in engineering quantum light sources.

Introduction In this article, we hypothesise how mainstream media coverage can promote the spread of disinformation about Covid-19. Mainstream media are often discussed as opposed to disinformation (Glasser; Benkler et al.). While the disinformation phenomenon is related to the intentional production and spread of misleading and false information to influence public opinion (Fallis; Benkler et al.), mainstream media news is expected to be based on facts and investigation and focussed on values such as authenticity, accountability, and autonomy (Hayes et al.). However, journalists might contribute to the spread of disinformation when they skip some stage of information processing and reproduce false or misleading information (Himma-Kadakas). Besides, even when the purpose of the news is to correct disinformation, media coverage might contribute to its dissemination by amplifying it (Tsfati et al.). This could be particularly problematic in the context of social media, as users often just read headlines while scrolling through their timelines (Newman et al.; Ofcom). Thus, some users might share news from the mainstream media to legitimate disinformation about Covid-19. The pandemic creates a delicate context, as journalists are often pressured to produce more information and, therefore, are more susceptible to errors. In this research, we focussed on the hypothesis that legitimate news can contribute to the spread of disinformation on social media through headlines that reinforce disinformation discourses, even though the actual piece may frame the story differently. The research questions that guide this research are: are URLs with headlines that reinforce disinformation discourses and other mainstream media links shared into the same Facebook groups? Are the headlines that support disinformation discourses shared by Facebook users to reinforce disinformation narratives? As a case study, we look at the Brazilian disinformation context on Covid-19. The discussion about the disease in the country has been highly polarised and politically framed, often with government agents and scientists disputing the truth about facts on the disease (Araújo and Oliveira; Recuero and Soares; Recuero et al.). Particularly, the social media ecosystem seems to play an important role in these disputes, as Brazilian President Jair Bolsonaro and his supporters use it as a key channel to spread disinformation about the virus (Lisboa et al.; Soares et al.). We use data from public groups on Facebook collected through CrowdTangle and a combination of social network analysis and content analysis to analyse the spread and the content of URLs and posts. Theoretical Background Disinformation has been central to the Covid-19 “infodemic”, created by the overabundance of information about the pandemic, which makes it hard for people to find reliable guidance and exacerbates the outbreak (Tangcharoensathien et al.). We consider disinformation as distorted, manipulated, or false information intentionally created to mislead someone (Fallis; Benkler et al.). Disinformation is often used to strengthen radical political ideologies (Benkler et al.). Around the world, political actors politically framed the discussion about the pandemic, which created a polarised public debate about Covid-19 (Allcott et al., Gruzd and Mai; Recuero and Soares). On social media, contexts of polarisation between two different political views often present opposed narratives about the same fact that dispute public attention (Soares et al.). This polarisation creates a suitable environment for disinformation to thrive (Benkler et al.) The polarised discussions are often associated with the idea of “bubbles”, as the different political groups tend to share and legitimate only discourses that are aligned with the group's ideological views. Consequently, these groups might turn into ideological bubbles (Pariser). In these cases, content shared within one group is not shared within the other and vice versa. Pariser argues that users within the bubbles are exposed exclusively to content with which they tend to agree. However, research has shown that Pariser’s concept of bubbles has limitations (Bruns), as most social media users are exposed to a variety of sources of information (Guess et al.). Nevertheless, polarisation might lead to different media diets and disinformation consumption (Benkler et al.). That is, users would have contact with different types of information, but they would choose to share certain content over others because of their political alignment (Bruns). Therefore, we understand that bubbles are created by the action of social media users who give preference to circulate (through retweets, likes, comments, or shares) content that supports their political views, including disinformation (Recuero et al.). Thus, bubbles are ephemeral structures (created by users’ actions in the context of a particular political discussion) with permeable boundaries (users are exposed to content from the outside) in discussions on social media. This type of ephemeral bubble might use disinformation as a tool to create a unique discourse that supports its views. However, it does not mean that actors within a “disinformation bubble” do not have access to other content, such as the news from the mainstream media. It means that the group acts to discredit and to overlap this content with an “alternative” story (Larsson). In addition, the mainstream media might disseminate false or inaccurate disinformation (Tsfati et al.). Particularly, we focus on inaccurate headlines that reinforce disinformation narratives, as social media users often only read news headlines (Newman et al.; Ofcom). This is especially problematic because a large number of social media users are exposed to mainstream media content, while exposure to disinformation websites is heavily concentrated on only a few users (Guess et al.; Tsfati et al.). Therefore, when the mainstream media disseminate disinformation, it is more likely that a larger number of social media users will be exposed to this content and share it into ideological bubbles. Based on this discussion, we aim to understand how the mainstream media contribute to the spread of disinformation discourses about Covid-19. Methods This study is about how mainstream media coverage might contribute to the spread of disinformation about Covid-19 on Facebook. We propose two hypotheses, as follows: H1: When mainstream media headlines frame the information in a way that reinforces the disinformation narrative, the links go into a “disinformation bubble”. H2: In these cases, Facebook users might use mainstream media coverage to legitimate disinformation narratives. We selected three case studies based on events that created both political debate and high media coverage in Brazil. We chose them based on the hypothesis that part of the mainstream media links could have produced headlines that support disinformation discourses, as the political debate was high. The events are: On 24 March 2020, Brazilian President Jair Bolsonaro made a public pronouncement on live television. In the week before the pronouncement, Brazilian governors decided to follow World Health Organisation (WHO) protocols and closed non-essential business. In his speech, Bolsonaro criticised social distancing measures. The mainstream media reproduced some of his claims and claims from other public personalities, such as entrepreneurs who also said the protocols would harm the economy. On 8 June 2020, a WHO official said that it “seems to be rare that an asymptomatic person transmits [Covid-19] onward to a secondary individual”. Part of the mainstream media reproduced the claim out of context, which could promote the misperception that both asymptomatic and pre-symptomatic persons (early stages of an illness, before the first symptoms) do not transmit Covid-19 at all. On 9 November 2020, Brazil’s national sanitary watchdog Anvisa reported that they had halted the clinical studies on the CoronaVac vaccine, developed by the Chinese company Sinovac. Bolsonaro often criticised CoronaVac because it was being produced in partnership with São Paulo’s Butantan Institute and became the subject of a political dispute between Bolsonaro and the Governor of São Paulo, João Dória. Bolsonaro said the halt of the CoronaVac trial was "another victory for Jair Bolsonaro". Anvisa halted the trail after a "severe adverse event". The mainstream media rapidly reverberated the decision. Later, it was revealed that the incident was a death that had nothing to do with the vaccine. Before we created our final dataset that includes links from the three events together, we explored the most shared URLs in each event. We used keywords to collect posts shared in the public groups monitored by CrowdTangle, a tool owned by Facebook that tracks publicly available posts on the platform. We collected posts in a timeframe of three days for each event to prevent the collection of links unrelated to the cases. We collected only posts containing URLs. Table 1 summarises the data collected. Table 1: Data collected Dates March 24-26 2020 June 8-10 2020 November 9-11 2020 Keywords “Covid-19” or “coronavirus” and “isolation” or “economy” “Covid-19” or “coronavirus” and “asymptomatic” “vaccine” and “Anvisa” or “CoronaVac” Number of posts 4780 2060 3273 From this original dataset, we selected the 60 most shared links from each period (n=180). We then filtered for those which sources were mainstream media outlets (n=74). We used content analysis (Krippendorff) to observe which of these URLs headlines could reinforce disinformation narratives (two independent coders, Krippendorff’s Alpha = 0.76). We focussed on headlines because when these links are shared on Facebook, often it is the headline that appears to other users. We considered that a headlined reinforced disinformation discourses only when it was flagged by both coders (n=21 – some examples are provided in Table 3 in the Results section). Table 2 provides a breakdown of this analysis. Table 2: Content analysis Event Mainstream media links Headlines that support disinformation discourses Number of links Number of posts Economy and quarantine 24 7 112 Asymptomatic 22 7 163 Vaccine trial 28 7 120 Total 74 21 395 As the number of posts that shared URLs with headlines that supported disinformation was low (n=395), we conducted another CrowdTangle search to create our final dataset. We used a sample of the links we classified to create a “balanced” dataset. Out of the 21 links with headlines that reinforced disinformation, we collected the 10 most shared in public groups monitored by CrowdTangle (this time, without any particular timeframe) (n=1346 posts). In addition, we created a “control group” with the 10 most shared links that neither of the coders considered could reinforce disinformation (n=1416 posts). The purpose of the “control group” was to identify which Facebook groups tend to share mainstream media links without headlines that reinforce disinformation narratives. Therefore, our final dataset comprises 20 links and 2762 posts. We then used social network analysis (Wasserman and Faust) to map the spread of the 20 links. We created a bipartite network, in which nodes are (1) Facebook groups and (2) URLs; and edges represent when a post within a group includes a URL from our dataset. We applied a modularity metric (Blondel et al.) to identify clusters. The modularity metric allows us to identify “communities” that share the same or similar links in the network map. Thus, it helped us to identify if there was a “bubble” that only shares the links with headlines that support disinformation (H1). To understand if the disinformation was supporting a larger narrative shared by the groups, we explored the political alignments of each cluster (H2). We used Textometrica (Lindgreen and Palm) to create word clouds with the most frequent words in the names of the cluster groups (at least five mentions) and their connections. Finally, we also analysed the posts that shared each of the 10 links with headlines that reinforced disinformation. This also helped us to identify how the mainstream media links could legitimate disinformation narratives (H2). Out of the 1346 posts, only 373 included some message (the other 973 posts only shared the link). We used content analysis to see if these posts reinforced the disinformation (two independent coders – Krippendorff’s Alpha = 0.723). There were disagreements in the categorisation of 27 posts. The two coders reviewed and discussed the classification of these posts to reach an agreement. Results Bubbles of information In the graph (Figure 1), red nodes are links with headlines that support disinformation discourses, blue nodes are the other mainstream media links, and black nodes are Facebook groups. Our first finding is that groups that shared headlines that support disinformation rarely shared the other mainstream media links. Out of the 1623 groups in the network, only 174 (10.7%) shared both a headline that supports disinformation discourse, and another mainstream media link; 712 groups (43.8%) only shared headlines that support disinformation; and 739 groups (45.5%) only shared other links from the mainstream media. Therefore, users’ actions created two bubbles of information. Figure 1: Network graph The modularity metric confirmed this tendency of two “bubbles” in the network (Figure 2). The purple cluster includes seven URLs with headlines that support disinformation discourse. The green cluster includes three headlines that support disinformation discourse and the other 10 links from the mainstream media. This result partially supports H1: When mainstream media headlines frame the information in a way that reinforces the disinformation narrative, the links go into a “disinformation bubble”. As we identified, most of the headlines that support disinformation discourse went into a separate “bubble”, as users within the groups of this bubble did not share the other links from the mainstream media. Figure 2: Network graph with modularity This result shows that users’ actions boost the creation of bubbles (Bakshy et al.), as they choose to share one type of content over the other. The mainstream media are the source of all the URLs we analysed. However, users from the purple cluster chose to share only links with headlines that supported disinformation discourses. This result is also related to the political framing of the discussions, as we explore below. Disinformation and Political Discourse We used word clouds (Lindgreen and Palm) to analyse the Facebook groups’ names to explore the ideological affiliation of the bubbles. The purple bubble is strongly related to Bolsonaro and his discourse (Figure 3). Bolsonaro is the most frequent word. Other prevalent words are Brazil, patriots (both related to his nationalist discourse), right-wing, conservative, military (three words related to his conservative discourse and his support of the military dictatorship that ruled Brazil from 1964 to 1985), President, support, and Alliance [for Brazil] (the name of his party). Some of the most active groups within the purple bubble are “Alliance for Brazil”, “Bolsonaro 2022 [next presidential election]”, “Bolsonaro’s nation 2022”, and “I am right-wing with pride”. Figure 3: Purple cluster word cloud Bolsonaro is also a central word in the green cluster word cloud (Figure 4). However, it is connected to other words such as “against” and “out”, as many groups are anti-Bolsonaro. Furthermore, words such as left-wing, Workers’ Party (centre-left party), Lula and Dilma Rousseff (two Workers’ Party ex-presidents) show another ideological alignment in general. In addition, there are many local groups (related to locations such as Rio de Janeiro, São Paulo, Rio Grande do Sul, Minas Gerais, and others), and groups to share news (news, newspaper, radio, portal). “We are 70 per cent [anti-Bolsonaro movement]”, “Union of the Left”, “Lula president”, and “Anti-Bolsonaro” are some of the most active groups within the green cluster. Figure 4: Green cluster word cloud Then, we analysed how users shared the mainstream media links with headlines that support disinformation discourses. In total, we found that 81.8% of the messages in the posts that shared these links also reproduced disinformation narratives. The frequency was higher (86.2%) when considering only posts that shared one of the seven links from the purple cluster (based on the modularity metric). Consequently, it was lower (64%) in the messages that shared one of the other three links. The messages often showed support for Bolsonaro; criticised other political and health authorities (the WHO, São Paulo Governor João Dória, and others), China, and the “leftists” (all opposition to Bolsonaro); claimed that quarantine and social distancing measures were unnecessary; and framed vaccines as dangerous. We provide some examples of headlines and posts in Table 3 (we selected the most-shared URL for each event to illustrate). This result supports H2 as we found that users shared mainstream media headlines that reinforce disinformation discourse to legitimate the disinformation narrative; and that it was more prevalent in the purple bubble. Table 3: Examples of headlines and posts Headline Post "Unemployment is a crisis much worse than coronavirus", says Bolsonaro Go to social media to support the President. Unemployment kills. More than any virus... hunger, depression, despair and everything UNEMPLOYMENT, THE DEPUTIES CHAMBER, THE SENATE AND THE SUPREME COURT KILL MORE THAN COVID19 Asymptomatic patients do not boost coronavirus, says WHO QUARANTINE IS FAKE #StayHome, the lie of the century! THIS GOES TO THE PUPPETS OF THE COMMUNIST PARTIES THE AND FUNERARY MEDIA Anvisa halts Coronavac vaccine trial after "serious adverse event" [The event] is adverse and serious, so the vaccine killed the person by covid And Doria [Governor of São Paulo and political adversary of Bolsonaro] wants to force you to take this shit This result shows that mainstream media headlines that support disinformation narratives may be used to reinforce disinformation discourses when shared on Facebook, making journalists potential agents of disinformation (Himma-Kadakas; Tsfati et al.). In particular, the credibility of mainstream news is used to support an opposing discourse, that is, a disinformation discourse. This is especially problematic in the context of Covid-19 because the mainstream media end up fuelling the infodemic (Tangcharoensathien et al.) by sharing inaccurate information or reverberating false claims from political actors. Conclusion In this article, we analysed how the mainstream media contribute to the spread of disinformation about Covid-19. In particular, we looked at how links from the mainstream media with headlines that support disinformation discourse spread on Facebook, compared to other links from the mainstream media. Two research questions guided this study: Are URLs with headlines that reinforce disinformation discourses and other mainstream media links shared into the same Facebook groups? Are the headlines that support disinformation discourses shared by Facebook users to reinforce disinformation narratives? We identified that (1) some Facebook groups only shared links with headlines that support disinformation narratives. This created a “disinformation bubble”. In this bubble, (2) Facebook users shared mainstream media links to reinforce disinformation – in particular, pro-Bolsonaro disinformation, as many of these groups had a pro-Bolsonaro alignment. 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