Differences In Migration Patterns Research Articles

Antarctic Skuas as bioindicators of local and global mercury contamination

Mercury (Hg) is a non-essential metal, sometimes extremely toxic, and its presence in the food-web may threaten the wildlife. In seabirds, even low levels of Hg can reduce egg production and the chances of embryos and chicks survival; high levels of this element lead to erratic behavior, loss of appetite and weight, and cellular damages in organs as kidneys can be detected. According to some authors, among 50 to 93% of the total Hg accumulated by the birds through diet can be excreted throughout the feathers during the molting process. In this way, feathers can be used as an excellent non-invasive biomonitor. The objective of this paper was to compared mercury (Hg) levels in feathers of adults and chicks of Catharacta maccormicki(Cma) and C. lonnbergi (Clo) sampled in the Antarctic Peninsula, to identify biomonitors of Hg to the region using non-invasive samples methods. We found Hg significantly higher levels in adults of Cma comparing with Clo adults (U'=841.00, p<0.01) and also with chicks of both species (q>3.398, p<0.01). We did not find significant differences comparing Clo adults and chicks of both species (U'=16.00, p<0.05), and comparing Cma breeding in different areas (q>3.398, p<0.05) or Clo (U'= 62.00, p < 0.05). The Hg levels variation may be justified mainly by differences in migration patterns. The adults of the species that migrate to more polluted areas (Cma) presented the highest levels of Hg and can be considered a promising indicator of global contamination. In another way, Clo and chicks of both species are good indicators of local Hg contamination, suffering the direct influence of contamination in the Antarctic environment.

The Early Northward Migration of the White-Backed Planthopper (Sogatella furcifera) is Often Hindered by Heavy Precipitation in Southern China during the Preflood Season in May and June.

Seasonal weather systems that establish prevailing winds and seasonal rainfall on a large scale largely determine insect migration patterns, especially for micro-insects with completely windborne migration. Recent studies indicated that the summer migration of the brown planthopper (BPH, Nilaparvata lugens) in eastern China is related to the strength and position of the Western Pacific Subtropical High-Pressure (WPSH) system and its associated wind and rainfall patterns. Compared with the BPH, the white-backed planthopper (WBPH, Sogatella furcifera) has a similar diet, analogous body size, and strong long-distance migration ability. Thus, the migration pattern for the WBPH can be speculated to be similar to that of the BPH. However, the migration pattern of the WBPH and how this pattern relates to climatic conditions have scarcely been described. Based on almost three decades of data (1977–2003), it was suggested that the WBPH in southern China (south of approximately 27° N) migrates into the middle and lower reaches of the Yangtze River after the abrupt movements of the WPSH in mid-June, similar to the BPH. By contrast, the emigration of the WBPH in southern China begins in late May. Further analysis indicated that the migration of the WBPH in late May and early June was short or unsuccessful due to heavy precipitation during the preflood season in southern China from late May to middle June. The results herein demonstrate the differences in migration patterns between two rice planthoppers in the eastern Asia migration arena. We also provide new information that could assist with forecasting outbreaks and implementing control measures against these migratory pests.

Species-specific maturation profiles of human, chimpanzee and bonobo neural cells.

Comparative analyses of neuronal phenotypes in closely related species can shed light on neuronal changes occurring during evolution. The study of post-mortem brains of nonhuman primates (NHPs) has been limited and often does not recapitulate important species-specific developmental hallmarks. We utilize induced pluripotent stem cell (iPSC) technology to investigate the development of cortical pyramidal neurons following migration and maturation of cells grafted in the developing mouse cortex. Our results show differential migration patterns in human neural progenitor cells compared to those of chimpanzees and bonobos both in vitro and in vivo, suggesting heterochronic changes in human neurons. The strategy proposed here lays the groundwork for further comparative analyses between humans and NHPs and opens new avenues for understanding the differences in the neural underpinnings of cognition and neurological disease susceptibility between species.

Understanding high-skilled intra-European migration patterns: the case of European physicians in Germany

ABSTRACTThis paper investigates migration patterns of European physicians in Germany as an example of high-skilled intra-EU migration. We define migration patterns as the migrants’ original migration decisions and the intended length of stay in their destination country. Our analysis is based on an original mixed-method study that consists of a survey (N = 1,225) and 22 semi-structured follow-up interviews with physicians from throughout the EU. Based on our data, we distinguish three classes of migration patterns: (1) ‘traditional labour migrants’, who emphasise economic and work-related migration reasons and intend to stay in Germany permanently, (2) ‘career seekers’, whose migration was triggered by the quality and content of employment and who only moved temporarily, and (3) ‘family settlers’, who indicate family reasons as crucial factors in their migration decision and mainly intend to remain in Germany. Western European physicians are overrepresented in the family settlers’ class, while Eastern European physicians are more likely to belong to the traditional labour migrants’ class. As an overarching concept to trace intra-EU migration is lacking, we hope to contribute to the emerging field of intra-EU migration research with an in-depth empirical study that accounts for differences in migration patterns with respect to different regions of origin.

Variability and repeatability of noctule bat migration in Central Europe: evidence for partial and differential migration.

Each year, large numbers of bats move across Europe between their summer and winter areas, yet even though many of them are endangered and legally protected, we are unaware about many aspects of their migratory behaviour. Here, taking Nyctalus noctula as a model species, we used stable hydrogen isotopic values in fur ( δ2Hf) as an endogenous marker to shed light on the migratory behaviour of more than 1000 bats from hibernacula across Central Europe. Specifically, we asked the following questions: how flexible is migration in temperate zone bats? Which general migration pattern do noctule bats follow? How repeatable and thus predictable is the migratory behaviour of individuals? Do morphological correlates of migration occur in bats? Our study confirmed that noctule bats engage in partial and female-biased migration across Europe, suggesting the strongest migration pressures for northern populations. Further, we revealed a combination of partial and differential migration patterns with highly variable migration distances which lead to a pronounced mixing of different source populations in hibernacula where mating occurs. Most individuals were consistent in their migration strategy over time, i.e. 86% could be repeatedly assigned to either long-distance or regional origin across years. This is consistent with our finding that the between-individual component explained 84% of the variation in δ2Hf values, suggesting specialized individual migratory behaviours and a strong natal philopatry. We discovered a positive correlation between forearm length and migration distance and support for sex-specific effects of migration on body condition. Our study elucidated migration patterns over large geographical scales, demonstrating that considerable numbers of migratory bats originating from distant populations depend on hibernacula across Central Europe, calling for international conservation management.

Constrained choices, enhanced aspirations: Transnational mobility, poverty and development. A case study from North Hungary

This paper aims to contribute to the exploration of the nexus of poverty, migration and development by providing what has been lacking thus far; namely, a close ethnographic portrait, combined with a survey, that interprets the most typical and diverging migration trajectories and their impacts in an economically backward and ethnically differentiated region in Hungary. Building on the inspirational work of anthropologists and mobility scholars who propose to recover a global and multidimensional perspective on transnational movement when exploring the nexus between migration and its consequences for development, we carried out multi-sited ethnography, both in the sending and in the destination localities. We also conducted a survey among migrants who had returned, sometimes temporarily, to their community of origin. Using this multi-spatial approach, we demonstrate the different layers of the migration-development nexus. We argue that, on the global level, receiving countries all benefit from the cheap and flexible labor of poor migrants, be they Roma or non-Roma, skilled or low-skilled mobile laborers. However, on the level of migrant-sending localities, due to the differential migration patterns of local Roma and non-Roma, the developmental effects of the two groups’ geographical movement cannot be taken as homogeneous or leveled. For non-Roma families, when men leave behind their wives and children for the sake of financial betterment of their family, there is little developmental effect on community level, but only in a narrow financial sense. However, we argue, drawing on Appadurai’s (2004) “capacity to aspire” concept, that for a fraction of some kinship groups of low-skilled Roma who mainly migrate with their whole family, transnational mobility may not be as successful financially as for the non-Roma, although it has future-oriented developmental elements by potentially enhancing capacity to aspire for both migrants and non-migrants.

Research the migration pattern of oil-gas interface in gas cap expansion reservoir

Gas is continuously driven into the oil rim with the decrease of the oil rim pressure during the process of gas-cap expansion. In order to study the morphological changes in the process of oil-gas interfacial migration, the one-dimensional displacement device is used to analyze the oil-gas interface at different displacement angle and displacement velocity. The results show that the migration of outer boundary is faster than the inner boundary of the oil and gas interface in the process of oil-gas interfacial migration, and there are big differences in migration pattern of oil-gas interface at different displacement angle and displacement velocity. In order to quantitative character the interface morphology with different the displacement angle and displacement velocity, the new factor is used to describe the oil and gas interface morphology and the value of the factor can be calculated using the displacement angle and displacement velocity. The relationship between oil-gas interface form factor and displacement velocity is logarithmically determined for different displacement angles, which can provide guidance for the rational exploitation of gas-cap expansion energy with gas cap reservoir to achieve the aim of improving the overall development effect of gas cap reservoir

A Novel Modeling Approach for Estimating Patterns of Migration into and out of San Francisco by HIV Status and Race among Men Who Have Sex with Men.

In the early 1980s, men who have sex with men (MSM) in San Francisco were one of the first populations to be affected by the human immunodeficiency virus (HIV) epidemic, and they continue to bear a heavy HIV burden. Once a rapidly fatal disease, survival with HIV improved drastically following the introduction of combination antiretroviral therapy in 1996. As a result, the ability of HIV-positive persons to move into and out of San Francisco has increased due to lengthened survival. Although there is a high level of migration among the general US population and among HIV-positive persons in San Francisco, in- and out-migration patterns of MSM in San Francisco have, to our knowledge, never been described. Understanding migration patterns by HIV serostatus is crucial in determining how migration could influence both HIV transmission dynamics and estimates of the HIV prevalence and incidence. In this article, we describe methods, results, and implications of a novel approach for indirect estimation of in- and out-migration patterns, and consequently population size, of MSM by HIV serostatus and race in San Francisco. The results suggest that the overall MSM population and all the MSM subpopulations studied decreased in size from 2006 to 2014. Further, there were differences in migration patterns by race and by HIV serostatus. The modeling methods outlined can be applied by others to determine how migration patterns contribute to HIV-positive population size and output from these models can be used in a transmission model to better understand how migration can impact HIV transmission.

Y-chromosome variation in Indian native cattle breeds and crossbred population

The paternally inherited Y chromosome markers have been used widely in population genetic studies to trace paternal lineages, to understand differences in migration pattern and populations admixture in animals. In the absence of crossing over, Y-chromosomal markers in the non-recombining male-specific region (MSY) are mostly transmitted as a haplotype. Recent studies of five polymorphic sites on DDX3Y, UTY and ZFY genes of bull MSY assisted in the identification of three haplotypes (Y1, Y2 and Y3) in contemporary cattle. Here we report the screening of five SNPs (ZFY9- 120> C/T; ZFY10- 655> C/T; DDX3Y1- 425>C/T; DDX3Y7 -123>C/T and UTY19-423>C/A) of bull MSY employing optimized and validated allele-specific PCR (AS-PCR) protocols that are useful in effective differentiation of bull/semen samples of Bos indicus and Bos taurus origin. Three haplotypes (Y1, Y2 and Y3) were identified in the present study by the screening of 181 bulls from 10 native cattle breeds and 50 HF crossbred. Y1 and Y2 haplotypes were restricted to HF crossbred with a frequency of 0.98 and 0.02, respectively. The high frequency of Y1 haplotype is possibly due to the occurrence of Y1 lineage predominantly in HF bulls. All the native cattle breeds were observed to have pure indicine haplotype (Y3). These cost effective AS-PCR protocols may be useful for reliable and accurate genotyping of Y-SNPs in diverse native cattle breeds, exotic and crossbred cattle populations.

Interacting effects of latitude, mass, age, and sex on winter survival of Surf Scoters (Melanittaperspicillata): implications for differential migration

We quantified variation in winter survival of Surf Scoters (Melanitta perspicillata (L., 1758)) across nearly 30° of latitude on the Pacific coast of North America to evaluate potential effects on winter distributions, including observed differential distributions of age and sex classes. We monitored fates of 297 radio-marked Surf Scoters at three study sites: (1) near the northern periphery of their wintering range in southeast Alaska, USA, (2) the range core in British Columbia, Canada, and (3) the southern periphery in Baja California, Mexico. We detected 34 mortalities and determined that survival averaged lower at the range peripheries than in the range core, was lower during mid-winter than during late winter at all sites, and was positively correlated with body mass within locations. Although neither age nor sex class had direct effects, mass effects led to differential survival patterns among classes. When simultaneously incorporating these interacting influences, adult males of mean mass for their location had highest survival at the northern range periphery in Alaska, whereas adult females and juveniles had higher survival at the range core and the southern periphery. Our observations help to explain patterns of differential migration and distribution reported for this species and highlight seasonal periods (mid-winter) and locations (range peripheries) of elevated levels of mortality for demographically important age–sex classes (adult females).

Differential Migration in the Common ChiffchaffPhylloscopus collybita: Sub-Saharan Wintering Grounds Host More Adults and Females as Well as Birds of Larger Size and Better Physical Condition

Summary. Avian migration strategies may include intra-specific variations, also known as differential migration. These migratory adaptations between conspecifics are particularly important given their implications for population dynamics. We aimed to examine the differential migration pattern as a function of age and sex, and whether this pattern also determines body morphology, in a passerine whose migration strategy includes movements to both pre- and sub-Saharan wintering areas. Thus, 1,100 common chiffchaffs Phylloscopus collybita were sampled during 2009–2012 at eight wintering locations within the Palearctic and Afrotropical regions. Biometric and body condition variables were studied for their relationship to geographical, climatic and productivity indexes. A higher proportion of adults and females were observed at lower latitudes. Common chiffchaffs were larger and in better body condition in sub-Saharan areas, coinciding with greater plant productivity and less annual rainfall. The selection of t...

Gender and intra-household migration decision in India: An Empirical Analysis

The objective of this paper is to understand the gender differences in migration patterns at the intra-household level and the socio-economic factors that cause such differences. Furthermore, the paper aims to explore the gender-specific dynamics of migration. The theoretical framework is drawn from the New Economics of Labour Migration model modified to address the gender dimension. In other words, the methodology highlights the linkage between NELM model and empirical evidence in order to understand the influence of gender in the migration decision making process in the household. Data from the National Sample Survey 2007-08 is used, along with the logistic regression technique in order to understand gender differences in migration in a household context. The empirical findings of the study reveal that in poor economic settings the risk of migration of women is higher than that of men within the household, indicating vulnerability of females both as bread winners and care takers. For meeting familial needs and to cope with household income risk most of the females choose migration as a livelihood strategy and therefore they migrate at a higher rate than males. This paper highlights the importance of gender in the household migration decision-making model.

Heterochronic parabiosis: allowing the dissection of the aged immune system (LYM2P.723)

Abstract Parabiosis is the surgical union of two organisms resulting in the development of a single, shared circulatory system. When animals of different ages are conjoined (i.e. heterochronic parabiosis), blood-borne factors from the younger animal can often beneficially affect the older animal and recapitulate the youthful phenotype & function in target tissues. However, the effects of heterochronic parabiosis on the aged immune system remain unexplored. An important question to be answered is whether the cellular defects involved in the aged immune system are due to intrinsic deficiencies or if they can be rescued by extrinsic factors. Also, T cell ontogenesis is known to diminish with age due to thymic involution as well as defects in lymphopoiesis that affect pre-T cells. The heterochronic parabiosis model allows testing of contributions of the aged thymus, pre-T cells and of systemic environment in immune aging. The preliminary data demonstrate differential migration patterns of T cells, B cells & dendritic cells as a function of age. Of interest, pre-T cells from either animal adequately seed the opposing thymus and undergo thymopoiesis and other data suggest that there are no intrinsic defects in old thymocytes, but rather of the old thymic environment. That latter defect may not be corrected by heterochronic parabiosis.

Levels and profiles of chlorinated and brominated contaminants in Southern Hemisphere humpback whales, Megaptera novaeangliae

The study documents the levels and profiles of selected contaminants [polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs) and methoxylated PBDEs (MeO-PBDEs)] in blubber biopsy samples collected from humpback whales (Megaptera novaeangliae) in Antarctic Peninsula waters. In addition, we investigated year-to-year and sex-related differences in the bioaccumulation patterns. Except for hexachlorobenzene (HCB), whose concentrations were in the same range as those found in whales from the Northern Hemisphere, levels of all other compounds were lower in Southern Hemisphere whales compared to literature data on animals from the Arctic and subarctic region. The mean contribution to the sum of all anthropogenic organohalogen compounds (ΣOHC) decreased in the following order ΣPCBs (44%)>HCB (31%)>ΣDDXs (13%)>ΣCHLs (4.6%)>ΣHCHs (4.4%)>ΣPBDEs (0.9%). The predominant compounds within each chemical class were: PCBs 153, 149, 101 and 138; p,p′-DDE; γ-HCH; trans-nonachlor; PBDEs 99 and 47. The most dominant MeO-PBDE congener was 6-MeO-BDE 47. As samples were collected during three consecutive summer seasons, year-to-year trends could be assessed indicating a significant decrease from 2000 to 2003 for ΣCHL levels. Higher ΣPBDE concentrations and higher values of the ΣPBDE / ΣMeO-PBDE ratio, as well as higher ratios between the two MeO-BDEs (2′-MeO-BDE 68/6-MeO-BDE 47) were found in females compared to males. Higher ΣMeO-PBDE concentrations and higher values of the ratios between the lower chlorinated and the higher chlorinated PCBs were found in males than in females. In addition, five out of six significant differences found through discriminant function analysis were gender-related. The literature reports both feeding in mid- to low-latitudes and sex-related differences in migration patterns for humpback whales from the Southern Hemisphere, indicating that the hypothesis of dietary differences between males and females cannot be excluded. Nevertheless, additional studies are required for further investigation of this hypothesis.

Seasonal differences in migration patterns of a soaring bird in relation to environmental conditions: a multi-scale approach

Many studies suggest that migratory birds are expected to travel more quickly during spring, when they are en route to the breeding grounds, in order to ensure a high-quality territory. Using data recorded by means of Global Positioning System satellite tags, we analysed at three temporal scales (hourly, daily and overall journey) seasonal differences in migratory performance of the booted eagle (Aquila pennata), a soaring raptor migrating between Europe and tropical Africa, taking into account environmental conditions such as wind, thermal uplift and day length. Unexpectedly, booted eagles showed higher travel rates (hourly speed, daily distance, overall migration speed and overall straightness) during autumn, even controlling for abiotic factors, probably thanks to higher hourly speeds, more straight routes and less non-travelling days during autumn. Tailwinds were the main environmental factor affecting daily distance. During spring, booted eagles migrated more quickly when flying over the Sahara desert. Our results raise new questions about which ecological and behavioural reasons promote such unexpected faster speeds in autumn and not during spring and how events occurring in very different regions can affect migratory performance, interacting with landscape characteristics, weather conditions and flight behaviour.

Economic and spatial determinants of interregional migration in Kazakhstan

In this paper we analyze economic and spatial determinants of interregional migration in Kazakhstan using quarterly panel data on region to region migration in 2008–2010. The main contribution of the paper relates to the ethnic divide in Kazakhstan, which is the home of a big ethnic Russian community, adding to the scarce literature on ethnic differences in migration patterns. Against this background we investigate whether the determinants of interregional mobility depend on ethnicity. In line with traditional economic theory we find that migration is determined by economic factors, first of all wage. As predicted by gravity arguments, mobility is larger between more populated regions and distance has a strong negative impact on migration, indicating high migration-related costs. Most likely caused by stronger family ties and kinship bonds, the deterring effect of distance is higher for ethnic Kazakhs.

Quantifying cross-border movements and migrations for guiding the strategic planning of malaria control and elimination.

BackgroundIdentifying human and malaria parasite movements is important for control planning across all transmission intensities. Imported infections can reintroduce infections into areas previously free of infection, maintain ‘hotspots’ of transmission and import drug resistant strains, challenging national control programmes at a variety of temporal and spatial scales. Recent analyses based on mobile phone usage data have provided valuable insights into population and likely parasite movements within countries, but these data are restricted to sub-national analyses, leaving important cross-border movements neglected.MethodsNational census data were used to analyse and model cross-border migration and movement, using East Africa as an example. ‘Hotspots’ of origin-specific immigrants from neighbouring countries were identified for Kenya, Tanzania and Uganda. Populations of origin-specific migrants were compared to distance from origin country borders and population size at destination, and regression models were developed to quantify and compare differences in migration patterns. Migration data were then combined with existing spatially-referenced malaria data to compare the relative propensity for cross-border malaria movement in the region.ResultsThe spatial patterns and processes for immigration were different between each origin and destination country pair. Hotspots of immigration, for example, were concentrated close to origin country borders for most immigrants to Tanzania, but for Kenya, a similar pattern was only seen for Tanzanian and Ugandan immigrants. Regression model fits also differed between specific migrant groups, with some migration patterns more dependent on population size at destination and distance travelled than others. With these differences between immigration patterns and processes, and heterogeneous transmission risk in East Africa and the surrounding region, propensities to import malaria infections also likely show substantial variations.ConclusionThis was a first attempt to quantify and model cross-border movements relevant to malaria transmission and control. With national census available worldwide, this approach can be translated to construct a cross-border human and malaria movement evidence base for other malaria endemic countries. The outcomes of this study will feed into wider efforts to quantify and model human and malaria movements in endemic regions to facilitate improved intervention planning, resource allocation and collaborative policy decisions.

Population-specific home ranges and migration timing of Pacific Arctic beluga whales (Delphinapterus leucas)

Two populations of beluga whales (Delphinapterus leucas), the Eastern Beaufort Sea (BS) and Eastern Chukchi Sea (ECS), make extensive seasonal migrations into the Pacific Arctic. However, the extent to which these populations overlap in time and space is not known. We quantified distribution and migration patterns for BS and ECS belugas using daily locations from whales tracked with satellite-linked transmitters. Home ranges and core areas in summer (July and August) and in each month (July–November), daily displacement, dispersal from core areas, and autumn migration timing were estimated. Distinct summer and fall distribution patterns and staggered autumn migration timing were identified for BS and ECS whales. Summer home ranges for each population had less than 10 % overlap. Monthly home ranges were also relatively distinct between populations except in September (up to 88 % home range overlap). A distinct east–west shift in focal area use occurred in September that persisted into October, with the two populations essentially switching longitudinal positions. Highest daily displacements occurred during the migratory period in September for BS whales and October for ECS whales, further indicating westward fall migration was offset between populations. Sexual segregation of males and females within a population also varied monthly. Autumn migration timing as well as differences in spatial and temporal segregation between BS and ECS beluga populations may be a result of maternally driven philopatry and population-specific adaptations to dynamically available resources. Our results contribute to the management of these populations by identifying seasonal area use and differences in migration patterns.

Geochemical Variations in Hydrocarbon Components Distribution in a Prograding Deltaic Sequence: A Case Study of the Baram Delta, Offshore Sarawak Basin, Malaysia

Studies on hydrocarbon distribution have evolved from basic reservoir characterization to complex studies today involving the interactions between oil components and clay minerals and sequential extraction studies on hydrocarbon extracts in reservoir rocks. Findings from such studies include the discovery of variations in oil fractions in reservoirs such as adsorbed oil and free oil. The theory that first oil charge preferentially interacts with clay minerals occurring in pores and as coatings in reservoirs was also proposed by some researchers. Despite, all these studies some aspects of variations in the composition of hydrocarbons in reservoir rocks still need to be investigated further. This study has been carried out particularly because the qualitative and quantitative composition of aromatic and aliphatic components of hydrocarbons in terms of the presence and quantities of hydrocarbon functional groups and how they relate to hydrocarbon migration have not been exhaustively discussed. This study uses Ultra-Violet visible light (UV-vis) and Fourier Transform Infra Red (FTIR) to characterize variations in hydrocarbon distribution in reservoir quality sandstones from three fields namely BD01, BD02 and BD03 in the Baram Delta, offshore Sarawak and to deduce how these variations relate to differential migration patterns in hydrocarbons. Hydrocarbon extraction was done in the ultra vilolet visible (UV-vis) experiment using 0.1M sodium pyrophosphate as solvent whereas in the Fourier Transform Infra Red (FTIR), the experiment was done on very fine powdered samples of the sandstones. Results from both the UV-vis and FTIR experiments indicate a dominance of aromatic functional groups in the samples. Most of the samples have E4/E6 ratio of more than 1 which indicates a high degree of aromacity. The BD01 field sandstones with a maximum porosity of 32% has the highest average E4/E6 ratio of 1.21, followed by the BD02 field sandstones with a maximum porosity of 29% and average E4/E6 ratio of 1.19 and the BD03 field with a maximum porosity of 20% and an average E4/E6 ratio of 1.09. The dominance of aromatics in the samples is interpreted as a possible indication of episodes of migration of aliphatics in the past leaving the aromatics behind with the variations in E4/E6 ratio reflecting the micro heterogeneities in the samples.

Spatial distribution and differences in migration patterns and revenues of gminas in the Kraków Metropolitan Area

AbstractIndicators describing the migration of population and revenues of local administrative units of the Krakow Metropolitan Area are presented and compared in this paper. A review of ideas on how to determine the number of Polish metropolitan statistical areas is also presented. The rank of Polish metropolitan statistical areas in world city rankings made by international publications is examined. Revenues of gminas from their own sources and total revenues of gminas are studied in the paper. Changes in revenue over time and location-dependent differences in revenue are analysed. However, the available data only allow for an examination of gminas without separating urban gminas from rural ones Substantial differences exist in the influx of revenue, both in terms of temporal and spatial changes. In order to summarise and evaluate the relevant social and economic processes, net migration of population and total revenue of gminas in the study area have been analysed. Furthermore, a classification of areas has been developed to describe the relevant areas as being of a certain type