Changes In Migration Patterns Research Articles

Moving On and Moving Back: Rethinking Inequality and Migration in the Latin American City

AbstractThis paper focuses on the similarities and differences between contemporary urban organisation and that of the 1960s in Guatemala City and other Latin American cities, mainly using data taken from a re-study of low-income neighbourhoods in Guatemala City. It looks at the impact of sharper patterns of residential segregation, changes in migration patterns, rising levels of crime and violence, and the increase in the relationships of the urban poor with external actors, such as governments and NGOs. Severe inequality persists, but is mediated by an improvement in living standards, by the range of consumer goods accessible to the poor, and by community- and family-based adaptation.

Worldwide invasion by the little fire ant: routes of introduction and eco-evolutionary pathways.

Biological invasions are generally thought to occur after human aided migration to a new range. However, human activities prior to migration may also play a role. We studied here the evolutionary genetics of introduced populations of the invasive ant Wasmannia auropunctata at a worldwide scale. Using microsatellite markers, we reconstructed the main routes of introduction of the species. We found three main routes of introduction, each of them strongly associated to human history and trading routes. We also demonstrate the overwhelming occurrence of male and female clonality in introduced populations of W. auropunctata, and suggest that this particular reproduction system is under selection in human-modified habitats. Together with previous researches focused on native populations, our results suggest that invasive clonal populations may have evolved within human modified habitats in the native range, and spread further from there. The evolutionarily most parsimonious scenario for the emergence of invasive populations of the little fire ant might thus be a two-step process. The W. auropunctata case illustrates the central role of humans in biological change, not only due to changes in migration patterns, but also in selective pressures over species.

Population Change in the Periphery: Changing Migration Patterns in the Russian North

Population Change in the Periphery: Changing Migration Patterns in the Russian North

Feminization of migrations?

Women have always taken part in migrations, but their presence varied depending on their origins, on the labour market situation both in the areas of origin and in the target areas, as well as the migration policies in the immigration areas. Their presence was not always visible and did not attract as much scholarly and political attention as today. What happened, how can one explain such an interest lately, whereas only few years ago the subject was marginal, in the shadow of the "mainstream - malestream", i.e. migration as a phenomenon which focuses on geographic mobility of men, while women are not considered as equal protagonists, they either follow or remain at home. Could the so called "feminization" of migration explain the great and sudden interest for women and gender in migrations? This text critically examines the notion of "feminization" considered today as one of the main dimensions of global migration flows. Drawing on trends both globally and in specific countries, it shows that "feminization" is neither a new nor a sudden trend and entails variations depending on the origins, level of development and maturity of migration flows. In some groups men were primo-migrants and with a gradual feminization the flows reach a balanced sex ratio. There where women migrated first, or became numerically predominant, one observs the opposite trend: a "masculinization". Some authors rightly refer to "gender transition", the term which covers both trends. It is argued in the conclusion that the visibility and growing interest for women in migration and, more recently, for a gender perspective in migration, is not only due to the changing migration patterns and profile of migrants but also to the renewal of theoretical perspectives in migration and gender studies in a context that largely facilitated that renewal. The focus of our attention today on specific aspects of migration is triggered not only by genuine changes in migration trends, but it is also a result of a long process of visibilisation in the academic production on migration, women and gender. These trends may have existed earlier in the migration history but had remained in the shadow of categories defining, recording and analyzing migration.

La démographie de l'Asie de l'Est et du Sud-Est des années 1950 aux années 2000

Résumé Avec ses 2,1 milliards d’habitants, l’Asie de l’Est et du Sud-Est rassemble le tiers de la population mondiale, notamment du fait de la présence de la Chine, pays le plus peuplé du monde, qui compte à elle seule 1,3 milliard d’habitants. Cette chronique propose à la fois une synthèse des grandes évolutions sociodémographiques et sanitaires depuis les années 1950 et un bilan statistique rassemblant les données récentes les plus fiables sur chaque pays. Y sont notamment examinés les effectifs et les structures de la population, la fécondité et ses variables intermédiaires, la nuptialité, la mortalité et la santé, les migrations internationales, l’urbanisation et l’accès à l’éducation. La région se distingue particulièrement par des progrès extraordinairement rapides réalisés tant dans le domaine de la lutte contre la mortalité que dans celui de la maîtrise de la fécondité. L’espérance de vie à la naissance est ainsi passée de 40 à 70 ans depuis le début des années 1950 et, grâce à des programmes de planification familiale souvent très interventionnistes mis en œuvre dans quelques pays, la fécondité est aujourd’hui, dans l’ensemble de la région, inférieure au seuil de remplacement des générations. Cette évolution conduit à de nouveaux défis démographiques dont les plus immédiats sont le vieillissement de la population, la réorientation des flux migratoires et, dans certains pays, un déséquilibre de la structure par sexe lié au recours massif aux avortements sélectifs.

Circannual basis of geographically distinct bird schedules

To anticipate seasonal change, organisms schedule their annual activities by using calendrical cues like photoperiod. The use of cues must be fitted to local conditions because schedules differ between species and habitats. In complete absence of temporal information, many species show persistent circannual cycles that are synchronised, but not driven, by photoperiod. The contribution of circannual rhythms to timing under natural photoperiodic conditions is still unclear. In a suite of experiments, we examined timing in two closely related songbirds (Siberian and European stonechats) that inhabit similar latitudes but differ in seasonal behaviour. Under a more continental climate, Siberian stonechats breed later, moult faster and migrate further than European stonechats. We tested hypotheses for seasonal timing mechanisms by comparing the birds under constant and naturally changing daylengths. The taxa retained characteristic reproductive and moult schedules and hybrids behaved roughly intermediately. Based on their distinct circannual cycles, we expected European and Siberian stonechats to differ in photoperiodic responses at a given time of year. We found that the taxa responded, as predicted, in opposite ways to photoperiodic simulations as experienced on different migration routes. The findings indicate that circannual rhythms reflect geographically distinct periodic changes in seasonal disposition and cue-response mechanisms. Under natural daylengths, the phase relationship of the underlying circannual rhythm to the external year determines the action of photoperiod. Circannual rhythms are widespread among long-lived species. Accordingly, responses to environmental change, range expansion and novel migration patterns may depend on the particulars of a species' underlying circannual programming.

Khat Use: Lifestyle or Addiction?

The khat plant contains psychoactive alkaloids with psychostimulant properties, and has been used for centuries as a recreational and religious drug, mainly in some African and Middle Eastern countries. With changing migrationpatterns, epidemiological and clinical outcomes may have changed. The aim of this article is to review current knowledge on pharmacological, epidemiological and clinical aspects of khat use. Khat use is still highly prevalent in the countries mentioned, and in African and Yemeniemigrant groups. Preclinical and clinical data confirm its addictivepotential as well as possible psychological, psychiatric and medical consequences related to stimulant use; however, existing epidemiological studies do not focus on the prevalence of problematic use or dependence. There are no indications of high prevalence of khat use in other cultural and ethnic groups. Data are lacking on possible increased psychotogenic risks when khat is used outside of the original cultural context. As with alcohol use in many countries, khat use can be considered as a lifestyle in some specific countries, covering the spectrum from nonproblematic use to problematic use and dependence. Khat dependence is associated with high morbidity and societal and economical costs.

Opposite effects of PDGF-BB and prostaglandin E 1 on cell-motility related processes are paralleled by modifications of distinct actin-binding proteins

Prostaglandin E 1 (PGE 1) lowers dermal interstitial fluid pressure (IFP) in vivo and inhibits fibroblast-mediated collagen gel contraction in vitro. PDGF-BB, in contrast, stimulates contraction and normalizes IFP lowered as a result of anaphylaxis. Human diploid AG1518 fibroblasts expressed EP2, EP3 and IP prostaglandin receptors. The inhibitory effect of PGE 1 on contraction depended on cAMP. Short-term stimulation with PDGF-BB transiently induced formation of actin-containing membrane and circular ruffles and breakdown of stress fibers. PGE 1 had no effect on stress fibers nor did it modulate the effects of PDGF-BB. PGE 1 alone or in combination with PDGF-BB inhibited initial adhesion and spreading to collagen. PDGF-BB had no effect on adhesion but stimulated cell spreading. Two-dimensional gel electrophoresis and MALDI TOF analyses of SDS/Triton X-100-soluble proteins revealed changes in migration pattern of actin-binding proteins. Interestingly, PDGF-BB and PGE 1 affected both similar and different sets of actin-binding proteins. PDGF-BB and PGE 1 did not trans-modulate their respective effects on actin-binding proteins, cytoskeletal organization or initial adhesion. Our data show that PDGF-BB stimulates actin cytoskeleton dynamics, whereas PGE 1 inhibits processes dependent on cytoskeletal motor functions. We suggest that these different activities may partly explain the contrasting effects of PGE 1 and PDGF-BB on contraction and IFP.

Holocene glacier fluctuations and migration of Neolithic yak pastoralists into the high valleys of northwest Bhutan

Here we present geomorphologic, palaeoenvironmental and archaeo-botanical data which elucidate the Late Pleistocene and Holocene glacial history of the high, mountain-locked Himalayan valleys in northwest Bhutan and provide one of the earliest proofs of human activity yet known for the High Himalaya range. In this area, difficult to access, close linkage between climatic change, glacier fluctuations and human migration patterns has been discovered. Glacier systems in the studied area are characterized by avalanching and debris mantled glacier snouts, with the significant local influence of the Indian summer monsoon causing decoupling of glacier responses from temperature changes but supporting the idea of monsoonal forcing. Geomorphologic mapping, together with Optically Stimulated Luminescence (OSL) and radiocarbon dating of ice-proximal sediments, has been used to construct a local glacial chronology. Local ice-stream networks developed during the Early Holocene (ca 10,000–9000 a ago) and during the early part of the Mid Holocene (6710 ± 90–4680 ± 155 cal a BP) at which times there were ice advances of about 5 km from the modern glacier termini. At such times, the intensity of pro- and periglacial processes would have intensified and ice-dammed lakes were probably common as well, rendering human colonization of the high valleys in northwest Bhutan impossible. An abrupt shift to dry climatic conditions on the Tibetan Plateau between 5000 and 4500 a BP coincided with glacial decay and the onset of morphodynamically stable conditions on the broad valley floors of the high valleys in this part of the Himalaya. Palynological data suggest that the sudden disappearance of juniper and rhododendron pollen, the immediate onset of pollen input from cereals (confirmed by detailed SEM analysis) and a clear pattern of over-grazing, trampling and peat deterioration can be linked to human arrival in the valleys at ca 4280 ± 130 cal a BP. Extensive charcoal horizons dating to 4745 ± 250 and 4680 ± 155 cal a BP are interpreted as evidence for human use of fire and forest clearances and agree spatially and temporally with the pollen-based picture. Charcoal occurrences as old as 6710 ± 90 cal a BP might be linked to yet earlier exploration of these Himalayan valleys during phases of low glacial activity. We provide an account of the colonization of these high valleys in response to glacial and monsoonal change and argue that the most likely founder societies come from the Tibetan Plateau, where yak and barley based pastoralism and Neolithic settlements are known to have existed since the Mid Holocene.

The five-year impact of an evolving global epidemic, changing migration patterns, and policy changes in a regional Canadian HIV population

To evaluate the impact of policy changes to Canada's Immigration Act and changing migration patterns on a regional HIV population. All HIV-positive individuals enrolled in care at the Southern Alberta Cohort between 2001 and 2007 were included and subdivided by self-reported country of birth. Demographic, clinical, and health utilization data were collected at each visit. We compare data and outcomes for each group and analyze changes since policy implementation. The proportion of immigrants/refugees increased significantly over the past five years. They present with lower CD4 counts, different HIV-subtypes, and previously rare co-morbidities. Management of disease progression necessitates more clinical visits and laboratory testing. Immigrants/refugees require greater social support to engage in, and to continue to access health care. Outcomes in HIV care were, however, equivalent to the Canadian-born population. The impact of changes to immigration policies is evident five years after implementation. Immigrant medical screening identifies increasing numbers of immigrants diagnosed with HIV. Immigrants require engagement in health care to achieve the full benefits of HIV management. Developed countries with increasing immigrant populations should be aware of how policy changes affect HIV prevalence rates, modes diagnosis and presentation, future clinical demands, and health care utilization.

Inferring Directional Migration Propensities from the Migration Propensities of Infants in the United States

Beginning with the 2010 decennial census, the U.S. Census Bureau plans to drop its long-form questionnaire and to replace it with the American Community Survey (ACS). The resulting absence of the larger sample provided by the census count will complicate the measurement and analysis of internal migration flows. In addition, the strategy of averaging accumulated samples over time will mix changing migration patterns. The migration question will refer to a one-year time interval instead of the five-year interval used in the censuses between 1960 and 2000, complicating historical comparisons and the production of multiregional projections based on five-year age groups. Consequently, students of territorial mobility increasingly will find it necessary to complement or augment possibly inadequate data collected on migration with estimates obtained by means of “indirect estimation.” A method is presented that allows one to infer age-specific directional migration propensities at the regional level from birthplace-specific infant population data, which approximates infant migration propensities, and from these infers the migration propensities of all other ages. The method is applied to at the nine-division spatial scale.

Stroke in pregnancy associated with syphilis

The Incidence of Syphilis has increased in developed countries over recent years. This potentially could lead to a rise in the number of cases presenting in obstetrics and a resurgence of congenital syphilis. Syphilis is a treatable condition, screening in pregnancy is both cost effective and cost beneficial. We describe a rare presentation of syphilis in a young woman in early pregnancy. The patient presented with a stroke, at which time her partner was diagnosed with early latent syphilis. Her findings were thought to be consistent with meningovascular syphilis and treatment lead to resolution of her symptoms. Antenatal screening for syphilis is offered to all women in the UK. Changing migration patterns and high-risk behavior however, may cause cases to go undetected. Vigilant screening for syphilis is needed in pregnancy as prompt diagnosis and management will aim to cure the mother whilst preventing the adverse effects associated with congenital syphilis.

The Heterogenous Citizen: How Many of Us Care about Don Bradman’s Average?

The Heterogenous Citizen: How Many of Us Care about Don Bradman’s Average?

Seasonal and ontogenetic variation in diel vertical migration of Chaoborus flavicans and its effect on depth‐selection behavior of other zooplankton

We analyzed diel vertical migration (DVM) of zooplankton in June, July, and September in Lake Kärnsjön, Sweden. In this lake, the density of the invertebrate predator Chaoborus flavicans was high, and they performed normal DVM. However, the migration pattern of Chaoborus differed between its four larval instars. Larger instars were found at greater mean depths during the day than were the smaller instars. In both June and July, very few observations of the fourth instar were made at a depth of 1 m during the night. Hence, in June, when only the fourth instar was present, the upper 1‐m layer was a Chaoborus‐free refuge for other zooplankton during the night. This was not the case in July, when the smaller instars (1‐3) hunt at that depth, or in September, when instar four was present there. Crustacean zooplankton showed great flexibility in their DVM behavior. In September, both Bosmina and small Daphnia tended to perform reverse DVM (i.e., they resided closer to the surface during the day). However, no migration was observed in July. In June, most species performed normal DVM by crowding in the Chaoborus‐free stratum close to the surface during the night. Both this pattern of normal DVM of zooplankton in June and the reverse DVM in September indicate that invertebrate predation has a strong effect on the zooplankton community in this fish‐rich lake, showing that ontogenetic changes in migration pattern of an invertebrate predator may influence the seasonal variation in the depth‐selection behavior of other zooplankton.

Towards consensus? Centre-right parties and immigration policy in the UK and Ireland

The UK has long experience of immigration; Ireland until very recently was a country of emigration. Over the past decade both states have opened their borders to large numbers of economic migrants, notably from the new EU member states. In both states, the major political parties have broadly welcomed globalization and the benefits it can bring, and it is hard to discern a distinctive centre-right approach. Traditionally, the Conservatives have been seen as tougher on immigration than Labour in the UK, yet there has been little difference in practice between the two parties' policies in government. In Ireland, Fine Gael has primarily criticized the way the government implements its policies rather than showing any fundamental difference over substance. This article considers the changing patterns of migration, how these have affected discourse and policy in the UK and Ireland, and looks at why there is not a distinct centre-right approach in either state.

The Heterogenous Citizen

The Heterogenous Citizen

Stemming the Tide of Hepatitis B Virus–Related Hepatocellular Carcinoma?

Infection with hepatitis B virus (HBV) is a major global public health problem, with an estimated prevalence of 350 million chronic carriers worldwide, and 1.5 million in the United States. The majority of HBV-infected individuals are concentrated in Asia and subSaharan Africa, but the incidence is rising is Western countries as a result of changing migration patterns. Chronic HBV infection can lead to liver cirrhosis, hepatic decompensation, and premature death. As many as 25% of HBV-infected patients will develop hepatocellular carcinoma (HCC), which is the fourth most common solid tumor worldwide. As much as a 50% reduction in the incidence of HBV transmission has been achieved in certain countries through widespread vaccination programs. Reduction in the morbidity and mortality of HBV-related HCC has been achieved as a result of intensive screening programs and through antiviral treatment with agents such as lamivudine and interferon. Because the majority of HCC cases worldwide are HBV-associated, HCC is truly a preventable malignancy. Given the considerable number of patients who are at risk for developing chronic HBV infection and its deadly sequelae, the costs associated with screening and treatment are similarly enormous. The challenge, therefore, is to select those patients most likely to benefit from HBV treatment and HCC screening to maximize the benefit-cost ratio of such programs. Any opportunity to optimize selection of patients for HBV treatment and HCC screening, and thereby reduce the incidence of HCC, should result in a significant public health benefit. HBV has been classified into eight genotypes, designated by capital letters A through H. HBV genotypes have distinct geographic distributions, with genotypes B and C being the most prevalent in Asia. Several studies have demonstrated that genotype C is associated with a higher prevalence of hepatitis B e antigen (HBeAg), more active hepatitis, and more advanced liver disease than genotype B. In a cross-sectional study of 270 Taiwanese HBV carriers with various forms of liver disease, genotype C was more prevalent in patients with cirrhosis and in those with HCC older than 50 years compared with age-matched asymptomatic carriers. Furthermore, HBV genotype C has been shown to be an independent risk factor for development of HCC. In a study of 426 Chinese patients infected with HBV, 25 patients developed HCC during a median follow-up of 121 weeks. Cirrhosis and HBV genotype C infection were independently associated with HCC development. In a study of 4,841 Taiwanese male hepatitis B s antigen (HBsAg) carriers, there were 154 cases of HCC diagnosed during a 14-year follow-up period. HBV DNA levels and HBV genotypes were determined for all patients with HCC and 316 control subjects. Results indicated that the risk of HCC increased with increasing HBV viral load. Moreover, genotype C was associated with an increased risk of HCC compared with other HBV genotypes (adjusted odds ratio [OR] 5.11; 95% CI, 3.20 to 8.18). In that study, the association of HBV genotype C and HBV viral load with HCC risk appeared to be additive. The adjusted OR of HCC for those carrying genotype C and with viral load in the highest quintile was 26.49 (95% CI, 10.41 to 67.42) compared with those carrying other HBV genotypes and lower viral loads. These and other recent studies have been paramount in our understanding of the factors that influence clinical outcome in HBV infection. However, it appears that HBV genotype is only one of the elements associated with hepatocarcinogenesis. Mutations in the basic core promoter (BCP) and precore regions carry an increased risk of HCC. In a cross-sectional, retrospective study of 160 chronic HBV carriers and 200 patients with HCC, advanced age, male sex, the precore A1896 mutation, the BCP T1762/A1764 mutation, and a high HBV load were significantly associated with development of HCC. There has also been recent interest in studying the relationship among HBV genotypes, subgenotypes, and mutations encountered in HBV carriers. Whether these have additive or synergistic effects on the risk of HCC development remains unclear. It has been reported that patients with genotype B have a higher chance of harboring precore mutations when compared with patients with genotype C. In the same study, core promoter mutations, T1653 mutations, HBV DNA levels of at least 4 log10 copies/mL, and cirrhosis were shown on to be independent risk factors for HCC. HBV genotype C has been classified into four subgenotypes: HBV/C1-C4. The designation of the two most widely disseminated subgenotypes is controversial. HBV/C1 (or Cs) is commonly found in Southeast Asia. HBV/C2 (or Ce) is found in East Asia including Japan and China. There are limited data on the clinical implications and JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 26 NUMBER 2 JANUARY 1

Migration, New Arrivals and Local Economies

Migration is ‘part of a transnational revolution that is reshaping societies and politics around the globe’ (Castles & Miller, 1993, p. 5). While processes of insertion, assimilation or integration involve transformations of migrants’ social, economic and cultural capital (Sassen, 1998), their integration is uneven and often incomplete (Soysal, 1994). Critically, whilst the drivers of migration may be related to global processes of economic and political change, the experiences and impacts of migration are strongly local. In this issue of Local Economy, we attempt to make some sense of the rapidly increasing and changing migration patterns in terms of their impact upon local economies and the policy challenges that result. The contributions here focus on the case of the UK, with experience too from Canada, and seek to provide a better understanding of the relationship between changing local economies and changing migrant streams, to begin to map out the local economic policy issues and emerging policy responses related to enterprise and labour market integration.

Reconstructing the migration patterns of late Pleistocene mammals from northern Florida, USA

We used analyses of the strontium isotope ( 87Sr/ 86Sr) ratios of tooth enamel to reconstruct the migration patterns of fossil mammals collected along the Aucilla River in northern Florida. Specimens date to the late-glacial period and before the last glacial maximum (pre-LGM). Deer and tapir displayed low 87Sr/ 86Sr ratios that were similar to the ratios of Florida environments, which suggest that these taxa did not migrate long distance outside of the Florida region. Mastodons, mammoths, and equids all displayed a wide range of 87Sr/ 86Sr ratios. Some individuals in each taxon displayed low 87Sr/ 86Sr ratios that suggest they ranged locally, while other animals had high 87Sr/ 86Sr ratios that suggest they migrated long distances (> 150 km) outside of the Florida region. Mastodons were the only taxa from this region that provided enough well-dated specimens to compare changes in migration patterns over time. Pre-LGM mastodons displayed significantly lower 87Sr/ 86Sr ratios than late-glacial mastodons, which suggests that late-glacial mastodons from Florida migrated longer distances than their earlier counterparts. This change in movement patterns reflects temporal changes in regional vegetation patterns.

Mining Migrants: Transnational Mining and Migration Patterns in the Peruvian Andes*

This article evaluates the linkages between transnational mining corporations and local migration dynamics in Peru. Changes in migration patterns in the Cajamarca region of Peru over the past decade are examined via a case study of the gold mining operations of Newmont Mining Corporation. The study considers household migration behavior in communities surrounding the mine as well as transformations in regional, national, and international migration patterns. Also examined are the temporal nature of these changing patterns across short, medium, and long-term time periods. *This research was conducted with the support of a National Science Foundation Regional Sciences DDRI (BCS-0002347) and the United States Fulbright Commission. All opinions, data, omissions, and errors are the sole responsibility of the author.