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In a temporal version of a single slit and Young’s double slit experiments, newly generated optical frequencies form a diffraction pattern. The spectral extent of these frequencies is beyond the expected bandwidth of the modulation.

Colloidal quantum dots are robust and flexible single photon emitters for room-temperature applications, but their purity is strongly reduced at high pump powers, due to multiexcitonic emission which cannot be easily filtered due to the photo-luminescence spectral broadening at room temperature. Giant-shell quantum dots feature a large blueshift of the biexciton spectrum due to electron-hole wave function engineering and piezoelectric charge separation, which can be exploited for spectral separation of the single exciton from the multiexciton emission. Here, by spectral filtering, we show that we can recover an excellent single-photon emission, with $g_2{(0)} < 0.05$ (resolution limited), even at high pump powers above saturation of the exciton emission. The bright and pure single-photon generation shown here has important applications in quantum information technology and random-number generation.

This paper aims to improve the understanding of migration-development links by comparing the evaluation of Mexico-US and Morocco-EU migration over the twentieth century. Despite significant differences, Mexico and Morocco share a common geopolitical location on the global South-North migration frontier as well as their position as prime source countries of predominantly low-skilled migrants into the US and EU. The analysis highlights the large extent to which Mexican and Moroccan migration is determined by political-economic transformations in the US and EU. Persistent economic gaps and migrant networks partly explain why, instead of decreasing migration, the recruitment freezes in Mexico (1964) and Morocco (1973) have contributed to increased reliance on family and irregular migration and a diversification of migration origins and destinations. Simultaneously, policy-driven changes in labour market structure caused an increased demand for casual and informal labour in the service sector, agriculture and construction. In light of this evidence, it would be naïve to expect the 2008 financial crisis to cause a fundamental shift in migration trends because political-economic conditions fuelling migration have remained unaltered. Similarly, in spite of the considerable contributions of Mexican and Moroccan remittances to the improvement of income and living standards in origin areas, it is unrealistic to assume that migration and remittances alone can overcome generically unfavourable development conditions. Therefore, improving general development conditions through structural political and economic reform seem the most viable policy to increase the development potential of migration. If such reform does occur, Morocco and, particularly, Mexico may transform into immigration countries in the medium to long term.

Using a historical approach, this paper examines the evolution of Guyanese migration from the 1950s until the 2010s. It explores the role of the Guyanese state in migration, the effect of independence and the establishment of a border regime on migration, with a particular focus on how political decisions and socio-economic policies have affected the timing, volume, composition and direction of migration in the post-independence period. After elaborating a new conceptual framework, the paper analyses the role of the Guyanese state across three broad historical phases: from the early 1950s to independence in 1966; from independence to the gradual political and economic opening of Guyana in 1985; and from 1986 to the present. The paper finds that the uncertainties generated by Britain’s introduction of its Immigration Act in 1962 and Guyana’s independence in 1966 led to two initial increases in emigration in the 1961-1962 and in 1965-66 periods. The Guyanese state’s support of 'cooperative socialism' and its authoritarian stance until the mid-1980s then promoted large emigration, which gradually included all classes and ethnic groups. At the same time, British and North American migration policies cause the partial redirection of migration towards the US and Canada. The importance of family re-unification and skilled migration channels explain on one hand, how entire Guyanese families have emigrated, while on the other hand, how Guyana is one of the top ten countries for skilled migrants. This paper shows the importance of shifting beyond the 'receiving country’ bias by considering the important role of origin country states in migration processes.

This paper argues that mobility and migration have always been an intrinsic part of human development. Migration can be considered as a fundamental capabilities-enhancing freedom itself. However, any meaningful understanding of migration needs to simultaneously analyse agency and structure. Rather than applying dichotomous classifications such as between forced and voluntary migration, it is more appropriate to conceive of a continuum running from low to high constraints under which migration occurs, in which all migrants deal with structural constraints, although to highly varying degrees. Besides being an integral part of human development, mobility also tends to affect the same structural processes of which it is part. Simplistic positive-versus-negative debates on migration and development can be overcome by integrating agency-structure dialectics in the analysis of migration impacts. This paper argues that (i) the degree to which migrants are able to affect structural change is real but limited; (ii) the nature of change in sending and receiving is not pre-determined; and (iii) that in order to enable a more focused and rigorous debate, there is a need to better distinguish and specify different levels and dimensions at which the reciprocal relationship between human mobility and development can be analysed. A critical reading of the empirical literature leads to the conclusion that it would be naïve to think that despite their often considerable benefits for individuals and communities, migration and remittances alone can remove more structural development constraints. Despite their development potential, migrants and remittances can neither be blamed for a lack of development nor be expected to trigger take-off development in generally unattractive investment environments. By increasing selectivity and suffering among migrants, current immigration restrictions have a negative impact on migrants’ wellbeing as well as the poverty and inequality reducing potential of migration.

Debates on migration policies are strongly focused on immigration control, revealing a general receiving-country bias in migration research. To fill this gap, this paper reviews the nature, evolution and effects of emigration policies. Only a declining number of strong, authoritarian states with closed economies are willing and capable of imposing blanket exit restrictions. Paradoxically, while an increasing number of, particularly developing, countries aspire to regulate emigration, their capability to do so is fundamentally and increasingly limited by legal, economic and political constraints. The attitude of states is often intrinsically ambiguous, as they face a complex trade-off between the perceived economic and political costs and benefits of emigration, in which who leaves greatly matters. This motivates states to adopt more subtle policies to encourage or discourage migration of particular skill, gender, age, regional or ethnic groups. Since state policies simultaneously constrain and enable migration of different groups to different destinations, states can play a significant role in structuring emigration through influencing the (initial) composition and spatial patterns of emigration. Even 'laissez-faire’ policies require active state agency to create the structural conditions for 'free’ emigration. However, the effect of emigration policies on overall volume and long-term trends of migration seems limited or even insignificant because of the preponderance of other economic, social and cultural migration determinants. This review reveals the need to improve insights into how states and policies shape migration processes in their interaction with other migration determinants in sending and receiving countries.

This paper looks at the relationship between migration between developing countries – or countries of the global 'South’ – and processes of human development. The paper offers a critical analysis of the concept of South-South migration and draws attention to four fundamental problems. First, there is no clear definition of the boundaries between 'South’ and 'North’ and different organisations place different countries in different categories. Second, migration systems tend to cut cross such boundaries, wherever they are place. Third, there is no analytical basis for distinguishing between 'South’ and 'North’; hence there is no rationale for assuming that South-South migration should be any different from South-North or North-North migration. Fourth, the available definitions of South and North change over time, creating difficulties for any longitudinal analysis. Having highlighted these problems, the paper then gives a broad overview of the changing patterns of migration in developing regions, with a particular focus on mobility within the African continent. It outlines some of the economic, social and political drivers of migration within poor regions, noting that these are also drivers of migration in the rest of the world. It also highlights the role of the state in influencing people’s movements and the outcomes of migration. The paper highlights the distinctive contribution that migration within developing regions makes to human development in terms of income, human capital and broader processes of social and political change. The paper concludes that the analysis of migration in poorer regions of the world and its relationship with human development requires much more data than is currently available. This should focus on understanding the role of migration (and mobility) in the lives of the poor. It is important to develop a much more sophisticated analysis of the differences in migration patterns across the world than that which can be achieved by simply dividing the world into crude blocks of 'South’ and 'North’.

This paper presents a conceptual framework to examine how the state shapes international migration in origin and destination countries, particularly in former colonies transitioning to independence or non-sovereignty. This paper proposes an expanded view of the state’s relevance in migration and introduces a conceptualisation of a country’s transition from colonial status to independence or non-sovereignty. This is done by presenting four hypothetical scenarios of the different ways in which migration patterns shift in reaction to the introduction and timing of independence and border regimes.

This paper outlines the conceptual and methodological underpinnings of DEMIG POLICY, a new database tracking major changes in migration policies of 45 countries between 1946 and 2013. Besides significantly extending the geographical and historical coverage of existing migration policy databases, DEMIG POLICY attempts to overcome the common 'receiving country bias’ by also including emigration policies. This paper describes the process of compiling migration policy data and shares insights into the theoretical foundations and the operationalization of a coding system that disaggregates policy packages into their sub-components, categorises specific policy types and target groups, and assesses changes in policy restrictiveness and their relative importance. This paper also addresses the challenges involved in the various phases of the database compilation. It stresses that theoretical considerations should guide the making of well-reasoned, non-arbitrary decisions on database features; and that transparency with regards to policy selection and coding decisions is essential to achieve consistency. The paper also underlines the importance of grounding the compilation and analysis of policy databases in a thorough understanding of the historical and political contexts in which those policies have emerged. Finally, the paper discusses the potential of DEMIG POLICY and its flexible coding system to increase insights into the nature and evolution of migration policies, and their interaction with migration and broader processes of economic and political change.

Over centuries past, human societies have been through fundamental changes often defined as ‘modernisation’. Despite huge advances in knowledge, social science has struggled to conceptualise the nature of these changes and to integrate insights from across different disciplines into a single framework. Disciplinary fragmentation and methodological parochialism as well as a postmodern aversion to ‘grand theory’ have impeded theoretical synthesis. To overcome this impasse, we introduce social transformation as a meta-theoretical conceptual framework for studying ‘big change’. Defining social transformation as a fundamental change in the way that societies are organised and resources are distributed, we distinguish five interconnected dimensions – the political, the economic, the technological, the demographic and the cultural – which together constitute the ‘social realm’. Studied simultaneously, these dimensions are able to capture ‘big change’ in its universal aspects while keeping sight of the diversity of its concrete manifestations. We apply this framework to explore how the ‘modern transformation’ has reshaped societies and to show how the interplay of the various political, economic, technological, demographic and cultural transitions have transformed social life around the globe in strikingly similar ways – notwithstanding the varied, unique ways in which this ‘modern transformation’ has concretely manifested itself across societies and over different periods.

Over centuries past, human societies have been through fundamental changes often defined as ‘modernisation’. Despite huge advances in knowledge, social science has struggled to conceptualise the nature of these changes and to integrate insights from across different disciplines into a single framework. Disciplinary fragmentation and methodological parochialism as well as a postmodern aversion to ‘grand theory’ have impeded theoretical synthesis. To overcome this impasse, we introduce social transformation as a meta-theoretical conceptual framework for studying ‘big change’. Defining social transformation as a fundamental change in the way that societies are organised and resources are distributed, we distinguish five interconnected dimensions – the political, the economic, the technological, the demographic and the cultural – which together constitute the ‘social realm’. Studied simultaneously, these dimensions are able to capture ‘big change’ in its universal aspects while keeping sight of the diversity of its concrete manifestations. We apply this framework to explore how the ‘modern transformation’ has reshaped societies and to show how the interplay of the various political, economic, technological, demographic and cultural transitions have transformed social life around the globe in strikingly similar ways – notwithstanding the varied, unique ways in which this ‘modern transformation’ has concretely manifested itself across societies and over different periods.

This paper studies the evolution of internal and international migration in Italy over the mid-nineteenth to the late-twentieth centuries. Notwithstanding Italy’s large international emigration flows, most Italian migration has been inter-regional, with rural-rural, rural-urban and urban-urban migration systems expanding in geographical scope and complexity over time. This paper analyses the interplay between internal and international migration, revealing four distinct patterns of (i) regions where internal migration always dominated and that turned into the destinations of internal migrants in the early-nineteenth century; (ii) regions that were initially characterised by strong international emigration before evolving into important destinations for internal migrants, (iii) regions that transitioned gradually from sources of to destinations for international and internal migrants and (iv) regions that largely remained sources of international and internal migration. Overall, these patterns reflect Italy’s social transformation from a feudal system in agricultural production to a modern welfare state with an industrial economy, a transformation which affected regions in strikingly different ways. More specifically, these ways are linked to state (re)formation, urbanisation, the rise of agricultural and industrial capitalism and the peripherisation of the South. These profound transformative processes altered the social structure and people’s livelihoods, engendering new opportunities in some regions and greater uncertainty in others. Rather than poverty, it was the combination of these transformative processes that encouraged many Italians to pursue migration. Because the social transformation unfolded unevenly across the Italian peninsula, it engendered inequalities and the (re)framing of central and more peripheral areas, which explains the different internal and international migration patterns.

Electron transfer to an individual quantum dot promotes the formation of charged excitons with enhanced recombination pathways and reduced lifetimes. Excitons with only one or two extra charges have allowed for the development of very efficient quantum dot lasing [1] and the understanding of blinking dynamics [2], while charge transfer management has yielded single quantum dot LEDs [3], LEDs with reduced efficiency roll-off [4], and enabled studies of carrier and spin dynamics [5]. Here, by room-temperature time-resolved experiments on individual giant-shell CdSe/CdS quantum dots, we show the electrochemical formation of highly charged excitons containing more than twelve electrons and one hole. We report control of intensity blinking, as well as a deterministic manipulation of quantum dot photodynamics, with an observed 210-fold increase of the decay rate, accompanied by 12-fold decrease of the emission intensity, all while preserving single-photon emission characteristics. These results pave the way for deterministic control over the charge state, and room-temperature decay-rate engineering for colloidal quantum dot-based classical and quantum communication technologies.

Time-varying metasurfaces are emerging as a powerful instrument for the dynamical control of the electromagnetic properties of a propagating wave. Here we demonstrate an efficient time-varying metasurface based on plasmonic nano-antennas strongly coupled to an epsilon-near-zero (ENZ) deeply subwavelength film. The plasmonic resonance of the metal resonators strongly interacts with the optical ENZ modes, providing a Rabi level spitting of ∼30%. Optical pumping at frequency ω induces a nonlinear polarization oscillating at 2ω responsible for an efficient generation of a phase conjugate and a negative refracted beam with a conversion efficiency that is more than 4 orders of magnitude greater compared to the bare ENZ film. The introduction of a strongly coupled plasmonic system therefore provides a simple and effective route towards the implementation of ENZ physics at the nanoscale.

This paper examines the social transformation processes that led to a mobility transition in Cisternino, a small agricultural town in Southern Italy. This transition entailed a shift from seasonal regional mobility in the 1940s to migration towards long-distance national and international destinations from the 1950s and to regional commuting and return migration from the 1970s. Building on mobility transition theories and the social transformation framework, the analysis examines the relation between the profound social change that affected this small agricultural town in the post-World War II period and shifts in migration. A combination of three broad processes explains the changing migration patterns: the expansion and consolidation of the state, the reshaping of the local economy and cultural transitions. By analysing the interplay and sequencing of these processes, we observe that, firstly, long-distance migration initially increased largely in reaction to deep cultural and political-economic shifts that altered local livelihoods; however, long-distance migration subsequently decreased as it was substituted by commuting in association with local economic growth and the expansion of state-driven sectors and safety net provisions that bore fruit in the 1960s. The article reveals the powerful and varied ways in which, in crucial moments of transition, the state affects local livelihoods and the population’s decision to either adapt locally or migrate.

Time-varying metasurfaces are emerging as a powerful instrument for the dynamical control of the electromagnetic properties of a propagating wave. Here we demonstrate an efficient time-varying metasurface based on plasmonic nano-antennas strongly coupled to an epsilon-near-zero (ENZ) deeply sub-wavelength film. The plasmonic resonance of the metal resonators strongly interacts with the optical ENZ modes, providing a Rabi level spitting of ~30%. Optical pumping at frequency {\omega} induces a nonlinear polarisation oscillating at 2{\omega} responsible for an efficient generation of a phase conjugate and a negative refracted beam with a conversion efficiency that is more than four orders of magnitude greater compared to the bare ENZ film. The introduction of a strongly coupled plasmonic system therefore provides a simple and effective route towards the implementation of ENZ physics at the nanoscale

Electrical conductance across a molecular junction is strongly determined by the anchoring group of the molecule. Here we highlight the unusual behavior of 1,4-bis(1H-pyrazol-4-ylethynyl)benzene that exhibits unconventional junction current versus junction-stretching distance curves, which are peak-shaped and feature two conducting states of 2.3 × 10−4 G0 and 3.4 × 10−4 G0. A combination of theory and experiments is used to understand the conductance of single-molecule junctions featuring this new anchoring group, i.e., pyrazolyl. These results demonstrate that the pyrazolyl moiety changes its protonation state and contact binding during junction evolution and that it also binds in either end-on or facial geometries with gold contacts. The pyrazolyl moiety holds general interest as a contacting group, because this linkage leads to a strong double anchoring of the molecule to the gold electrode, resulting in enhanced conductance values.

What have been the main trends and drivers of international migration over the last century, and to what extent have migration policies been effective in shaping the volume, direction, timing, and selection of immigration and emigration? This paper reviews the insights on migration trends, determinants and policy effects gained through the DEMIG (Determinants of International Migration) project. Questioning popular perceptions of accelerating international migration, the increase in global migration has remained proportional to the increase in world population. The main migratory shifts in the second half of the twentieth century have been directional, particularly through the decline of Europe as an area of origin and the emergence of Europe and the Gulf as new global destinations. This shift in migration movements towards Europe has been associated by an overall liberalisation of migration policies, which have increasingly focused on the selecting of migrants rather than controlling numbers per se. Most rules around legal entry, stay and exit of migrants have been relaxed, but a combination of visa and border control policies have served to prevent the entry of asylum seekers and other "unwanted" migrants. Our analysis shows that it would therefore be excessive to conclude that borders are "beyond control" (cf. Bhagwati 2003), and that migration policies are generally effective. Yet several "substitution effects" limit or undermine the effectiveness of migration controls by (1) redirecting migration through other geographical routes and destinations (spatial substitution), (2) diverting migration through other legal and unauthorized channels (categorical substitution), (3) "now or never" migration surges in anticipation of restrictions (intertemporal substitution) and (4) discouraging return and interrupting circulation (reverse flow substitution). These expose fundamental policy dilemmas as well as the importance to look beyond migration policies. Our results show the importance of accounting for the complex and often counterintuitive ways in which structural social, economic, and political factors affect migration in mostly indirect, but powerful ways that largely lie beyond the reach of migration policies.

Preparing for future changes in international migration requires an understanding of the different ways in which societies may change and how these will affect migration patterns. This requires us to move beyond traditional approaches of migration forecasting, which tend to focus on a limited set of relatively certain, easy-to-predict factors, such as demographic trends, and which assume structural continuity, by exploring methodologies that are suited to examine factors such as geopolitical shifts, economic restructuring, technological change and environmental change, which are notoriously difficult to predict, but which we cannot afford to ignore, since they will have a considerable impact on global migration patterns and trends. To this end, this paper presents the Global Migration Futures (GMF) Scenario Methodology developed at the University of Oxford’s International Migration Institute (IMI). The GMF Scenario Methodology integrates insights from migration theory with techniques from the Intuitive Logics School of scenario planning to enable the simultaneous and systematic examination of relatively certain and uncertain migration determinants, their future evolution as well as their implications for population mobility. In addition, this paper discusses the key insights gained through the application of the GMF Scenario Methodology in different world regions as well as its main limitations.

Background: The administration of abiraterone acetate (abiraterone) leads to an adrenocorticotropic hormone (ACTH)-driven increase in mineralocorticoid hormones, requiring glucocorticoid supplementation that may stimulate the growth of prostate cancer (PCa). Amiloride is a drug that selectively reduces the aldosterone-sensitive Na+/K+ exchange and could be effective in the management of mineralocorticoid excess syndrome (MCES). Methods: The efficacy of amiloride + hydrochlorothiazide (HCT) in the clinical management of abiraterone-induced MCES was assessed in 5 consecutive patients with castration-resistant PCa (CRPC). Then, using the in vitro experimental model of PCa cell lines, the possible effects of drugs usually used in the clinical management of CRPC patients on PCa cell viability were investigated. Results: Amiloride/HCT led to a complete disappearance of all clinical and biochemical signs of abiraterone-induced MCES in the 5 treated patients. The in vitro study showed that abiraterone treatment significantly decreased cell viability of both androgen receptor (AR)-expressing VCaP (vertebral-cancer of the prostate) and LNCaP (lymph node carcinoma of the prostate) cells, with no effect on AR-negative PC-3 cells. Prednisolone, spironolactone, and eplerenone increased LNCaP cell viability, while amiloride reduced it. The non-steroid aldosterone antagonist PF-03882845 did not modify PCa cell viability. Conclusions: The combination of amiloride/HCT was effective in the management of abiraterone-induced MCES. Amiloride did not negatively interfere with the abiraterone inhibition of PCa cell viability in vitro.

Migration research on the Three Guianas has primarily focused on ‘overseas’ emigration towards European and North American destinations. This has resulted in literature on Surinamese migration to the Netherlands (De Bruijne and Schalkwijk 1994; Gowricharn and Schuster 2001; Reubsaet 1984; Van Amersfoort 2011), Guyanese migration to Britain and North America (Kirton and Lewis 2015; Roopnarine 2013) and a limited but growing body of research on French Guianese migration to France (Calmont 1978, 1981; Calmont 1988; Marie et al. 2012; Marie and Rallu 2004; Temporal, Marie and Bernard 2011). To a large extent, the important volumes and concentrations of migration from the Three Guianas to Europe and North America justify this focus. However, this has resulted in a lack of comparative research exploring the similarities and differences in these countries’ migration evolutions and identifying the migration effects of important political and socioeconomic developments in each country. Moreover, there has been a general failure to fully account for the various forms of mobility within and across the Guianas, including the large forested areas in the interior, and their association to the processes of socioeconomic and political transformation that have occurred in the Three Guianas. This chapter presents insights gained from comparing migration in the Three Guianas with particular attention to how major political and socioeconomic processes, including independence, the establishment of the borders and broader processes of development, have shaped various forms of migration in the Three Guianas.