Mercury as the Relic of Earth and Venus Outward Migration

In spite of substantial advancements in simulating planet formation, the planet Mercury’s diminutive mass and isolated orbit and the absence of planets with shorter orbital periods in the solar system continue to befuddle numerical accretion models. Recent studies have shown that if massive embryos (or even giant planet cores) formed early in the innermost parts of the Sun’s gaseous disk, they would have migrated outward. This migration may have reshaped the surface density profile of terrestrial planet-forming material and generated conditions favorable to the formation of Mercury-like planets. Here we continue to develop this model with an updated suite of numerical simulations. We favor a scenario where Earth’s and Venus’s progenitor nuclei form closer to the Sun and subsequently sculpt the Mercury-forming region by migrating toward their modern orbits. This rapid formation of ∼0.5 M ⊕ cores at ∼0.1–0.5 au is consistent with modern high-resolution simulations of planetesimal accretion. In successful realizations, Earth and Venus accrete mostly dry, enstatite chondrite–like material as they migrate, thus providing a simple explanation for the masses of all four terrestrial planets, the inferred isotopic differences between Earth and Mars, and Mercury’s isolated orbit. Furthermore, our models predict that Venus’s composition should be similar to the Earth’s and possibly derived from a larger fraction of dry material. Conversely, Mercury analogs in our simulations attain a range of final compositions.

Proving the Availability of Ni-Fe Anode for Electro-Reduction of Solid V2O3 in Molten Fluoride Salts

The availability of casting Ni-Fe alloy as inert anode for direct electro-reduction of V2O3 in molten Na3AlF6-K3AlF6-AlF3 was investigated. The electrochemical oxidation behavior of anode as well as microstructural evolutions of formed oxide scale were systematically studied. The electrochemical characterization and reaction mechanism of cathode oxide were also investigated to evaluate the influence of alloy anode on cathodic reduction process. The in situ formed three-layered oxide scale is compact and coherent, which is composed of an outermost Fe2O3+FeAl2O4 skin layer, a Fe2O3 middle layer and a FeAl2O4 inner layer. The skin layer has a continuous, smooth structure and shows electrochemical activity. The Fe2O3 layer with compact structure prevents inward diffusion of electrolyte and outward migration of metal cations. The innermost FeAl2O4 layer shows a loose structure and functions as buffer layer to improve the peeling resistance of oxide scale. With the continuous extension of polarization time, the inner FeAl2O4 layer is slowly oxidized and becomes thinner, simultaneously, the dense Fe2O3 layer becomes thicker. Ultimately, metal vanadium product with fine rod-like particles can be obtained and the oxygen content in the metal vanadium is below 0.3 mass% within electrolyzing time of 2 h. The corresponding current efficiency is around 63%.

Development Strategies of the Bahari Jawai Marine Tourism Coast Area Based on Community Empowerment in Sambas Regency

Tourism is an important sector that can increase coastal country’s economies. The industry of tourism has been increasing in recent years and it can generate job opportunities, reduce outward migration, increase the income level, and improve the livelihood of local communities. This paper outlines the potentials and characteristics of natural and human resources as a proponent of the development of marine coast tourism based on community empowerment. This study aims to analyze the potential of resources and the suitability of tourism area which is supporting the attraction of tourists factor to come to Bahari Jawai beach and to develop a strategy for developing the marine tourism area of Sambas Regency based on natural resource potential, perceptions, participation, and aspirations of tourists and the community local. This research method is a descriptive method with the nature of a case study. Data collection was using observation and literature review and was analyzed with quantitative and qualitative analysis on each indicator. The development strategies in this study are 1). Strengthening marine tourism management; 2). Optimizing promotion and socialization on internet media; 3). Optimizing institutional roles in improving coastal security systems and health protocols; 4). Development of accessibility such as supporting facilities for coastal facilities and infrastructure.

The Context

London during the Victorian period was the largest city in the world, a focus for migration, and the centre of international finance, trade, and manufacturing as well as technological and scientific research, and the seat of imperial government. Its population included the very rich and the very poor, and a rapidly expanding professional and commercial middle class. Despite its vast and growing population, the metropolis had no formal identity and no central authority to coordinate services with the result that for much of the period water supplies and waste disposal were chaotic. With overcrowded housing, disease was endemic, and the death rate high. London was a very unhealthy place. Commercial success led to major redevelopment in the centre, and constant outward migration leading to suburbanization, a developing suburban transport network, segregation of classes, and a rapidly expanding leisure industry. Fluctuations in trade and economic downturns led to financial insecurity and political anxieties, periods of extreme distress among the poorest contributing to social unrest and fuelled millenarian hopes and fears. This provided the context for an extraordinary level of religious and religiously inspired philanthropic activity.

Learning to Leave and to Return: Mobility, Place, and Sense of Belonging amongst Young People Growing up in Border and Rural Regions of Mainland Portugal

This article examines how mobility is incorporated into the lives of young people growing up in rural border regions of continental Portugal. It also explores how municipalities are dealing with the contemporary imperative of mobility and its consequences. Young people from these regions are affected by decisions to leave to continue studying in higher education, or to find a job. Combined, these lead to an outward migration trend and thus loss of human capital. This paper is based on a multi-method research project carried out in the border regions and involves young people and other stakeholders from 38 municipalities. The data were selected from a questionnaire completed by young people (9th–12th grade; n = 3968), 38 semi-structured interviews with local policymakers, 50 biographical interviews, and 5 focus groups with young people. Results indicate that although most young people aspire to further education and do not fear leaving their region, they nonetheless tend to integrate the necessity to be mobile into their biographies. Hence, they do not associate it with displacement or as being tantamount to abandoning their region, and to which some of them want to return. We consider that in parallel with learning to leave local sentiments, policies, and actions are emerging towards coalescing a trend of learning to stay and returning. We propose an interpretation of this tendency as indicative of new understandings around these peripheral territories and which are shaped by young people’s experience of reconciling a sense of belonging to place and any associated mobilities.

DETERMINANTS OF YOUTH EMIGRATION: A CASE STUDY OF KARACHI (An Overview of emigration from 2010 to 2016)

In the last six years, more than 3.7 million people have migrated from Pakistan to seek employment, mostly in the Middle East. Approximately, 1 million people migrated from Pakistan in 2015 in contrast to 0.75 million in 2014, an increase of about 20.84%. People from all the cities of Pakistan are migrating, especially from Karachi, which is the seventh most populous city of the world and largest in Pakistan. More than 30% of Karachi’s population is youth (ages 15 –29) with 54.9% male and 45.1% female. This study finds that 48.7% of the youth in Karachi want to leave Pakistan for various reasons, including unemployment, insecurity, economic problems, lack of social support, lack of career opportunities. This high rate of outward migration from Pakistan is creating brain drain conditions, especially in the health and education sectors, where there is a shortage of skilled workforce. This paper explores and analyzes factors that are contributing to youth emigration from Pakistan’s largest city, Karachi.

A Regretful Journey Home: Albanian Return Migration in the Wake of the Global Financial Crisis of 2008

Despite occurring almost a decade ago, the effects of the 2008 global financial crisis continue to influence the lives of many people today. Intra-European migration literature, for example, suggests that migration patterns were reshaped in its aftermath and emerging literature details mobilities and experiences of migrants in destination societies post-crisis. To date, less research documents the experiences of individuals who, in the wake of the crisis, were forced to abandon their migratory endeavours and had to navigate returning to their country of origin in a particularly challenging socio-economic context. Utilising in-depth interviews and family case studies with purposively recruited Albanian return migrants who had lived in Greece and Italy pre-crisis, the current study highlights how conditions in both destination and origin countries impacted return experiences. Findings illustrate an adverse interplay of circumstances that led to the unsettled return and portray a perturbing fluidity in the lives of return migrants who appear overcome by a sense of ‘double failure’ with regard to both outward migration and subsequent return to their country of origin.

Which planets trigger longer-lived vortices: low-mass or high-mass?

Recent ALMA observations have found many protoplanetary discs with rings that can be explained by gap-opening planets less massive than Jupiter. Meanwhile, recent studies have suggested that protoplanetary discs should have low levels of turbulence. Past computational work on low-viscosity discs has hinted that these two developments might not be self-consistent because even low-mass planets can be accompanied by vortices instead of conventional double rings. We investigate this potential discrepancy by conducting hydrodynamic simulations of growing planetary cores in discs with various aspect ratios (H/r = 0.04, 0.06, 0.08) and viscosities (1.5 × 10−5 ≲ α ≲ 3 × 10−4), having these cores accrete their gas mass directly from the disc. With α < 10−4, we find that sub-Saturn-mass planets in discs with H/r ≤ 0.06 are more likely to be accompanied by dust asymmetries compared to Jupiter-mass planets because they can trigger several generations of vortices in succession. We also find that vortices with H/r = 0.08 survive >6000 planet orbits regardless of the planet mass or disc mass because they are less affected by the planet’s spiral waves. We connect our results to observations and find that the outward migration of vortices with H/r ≥ 0.08 may be able to explain the cavity in Oph IRS 48 or the two clumps in MWC 758. Lastly, we show that the lack of observed asymmetries in the disc population in Taurus is unexpected given the long asymmetry lifetimes in our low viscosity simulations (α ∼ 2 × 10−5), a discrepancy we suggest is due to these discs having higher viscosities.

Hong Kong-UK migration could rise significantly

Significance The scheme has become part of a broader diplomatic fight between London and Beijing that began during anti-government protests in Hong Kong in 2019 and worsened following Beijing’s imposition of a repressive National Security Law last year. Impacts Western countries may try to attract Hongkongers, who tend to be highly educated, though domestic politics may hinder this. Immigration to and from Hong Kong will likely be increasingly hostage to broader relations between Beijing and Western governments. Potential staffing gaps in Hong Kong due to outward migration could increasingly be filled by migrants from mainland China.