High Migration Rates Research Articles

Migration aspirations from a youth perspective: focus groups with returnees and youth in Mali

AbstractMali has one of the highest migration rates in Africa, but we still know very little about the processes and drivers of migration – particularly in the context of the current political crisis. This article draws on 27 focus groups with 220 returnees and male youth respondents conducted in the summer of 2018. Respondents cite underemployment and the inability to provide for relatives as well as a feeling of hopelessness about a future life in Mali as drivers of migration. Returnees report that the voyage was more difficult than anticipated. However, even with knowledge of the significant risks they face, most (68%) returnees express a desire to try to migrate again: this is particularly true for returned migrants who failed in an attempt to reach Europe (89%). The research illustrates very different experiences for migrants attempting to reach Europe and those with goals of intra-African migration.

Spatial inequality, characteristics of internal migration, and pulmonary tuberculosis in China, 2011\u20132017: a spatial analysis

BackgroundHuman migration facilitate the spread of tuberculosis (TB). Migrants face an increased risk of TB infection. In this study, we aim to explore the spatial inequity of sputum smear-positive pulmonary TB (SS + PTB) in China; and the spatial heterogeneity between SS + PTB and internal migration.MethodsNotified SS + PTB cases in 31 provinces in mainland China were obtained from the national web-based PTB surveillance system database. Internal migrant data were extracted from the report on China’s migrant population development. Spatial autocorrelations were explored using the global Moran’s statistic and local indicators of spatial association. The spatial variation in temporal trends was performed using Kulldorff’s scan statistic. Fixed effect and spatial autoregressive models were used to explore the spatial inequity between SS + PTB and internal migration.ResultsA total of 2 380 233 SS + PTB cases were reported in China between 2011 and 2017, of which, 1 716 382 (72.11%) were male and 663 851 (27.89%) were female. Over 70% of internal migrants were from rural households and had lower income and less education. The spatial variation in temporal trend results showed that there was an 9.9% average annual decrease in the notification rate of SS + PTB from 2011 to 2017; and spatial clustering of SS + PTB cases was mainly located in western and southern China. The spatial autocorrelation results revealed spatial clustering of internal migration each year (2011–2017), and the clusters were stable within most provinces. Internal emigration, urban-to-rural migration and GDP per capita were significantly associated with SS + PTB, further, internal emigration could explain more variation in SS + PTB in the eastern region in mainland. However, internal immigration and rural-to-urban migration were not significantly associated with SS + PTB across China.ConclusionsOur study found the spatial inequity between SS + PTB and internal migration. Internal emigration, urban-to-rural migration and GDP per capita were statistically associated with SS + PTB; the negative association was identified between internal emigration, urban-to-rural migration and SS + PTB. Further, we found those migrants with lower income and less education, and most of them were from rural households. These findings can help stakeholders to implement effective PTB control strategies for areas at high risk of PTB and those with high rates of internal migration.

Customized bariatric stents for sleeve gastrectomy leak: are they superior to conventional esophageal stents? A systematic review and proportion meta-analysis.

Recently, there has been a burgeoning interest in the utilization of customized bariatric stents (CBS) for management of sleeve gastrectomy leak (SGL). We aimed to conduct a proportion meta-analysis to evaluate the cumulative efficacy and safety of these new stents and to compare them with the conventional esophageal stents (CES). A systematic literature search of the PubMed, Cochrane Library, Scopus, Web of Science and Google Scholar databases was conducted through May 1, 2020. Primary outcomes were technical and clinical success and post-procedure adverse events of CBS and CES. Secondary outcomes were number of stents and endoscopic sessions per patient, and time to leak closure. A proportion meta-analysis was performed on outcomes using a random-effects model, and the weighted pooled rates (WPRs) or mean difference with 95% confidence interval (CI) were calculated. The WPR with 95% CI of technical success, clinical success, and stent migration for CBS were 99% (93-100%) I2 = 34%, 82% (69-93%) I2 = 58%, and 32% (17-49%), I2 = 69%, respectively. For CES, the WPR (95% CI) for technical success, clinical success, and stent migration were 100% (97-100%) I2 = 19%, 93% (85-98%) I2 = 30%, and 15% (7-25%), I2 = 41%, respectively. Adverse events other than migration were very low with both types of stents. On proportionate difference, CBS had lower clinical success (11%) and higher migration rate (17%) in comparison to CES. In successfully treated patients, CBS was associated with lower mean number of stents and endoscopic sessions, and shorter time to leak closure compared to CES. The overall quality of evidence was very low. In treatment of SGL, there is very low level evidence that CES are superior to CBS in terms of clinical success and migration rate, though may require more stent insertions and endoscopic procedures. The evidence however remains very uncertain. Perhaps relevant to some types of stents, CBS are promising; however design modification is strongly recommended to improve outcomes.

Socio-Economic Situation of Kosovan Migrants before and after Migration

In the 20th century and at the beginning of the 21st century, Kosovan society faced numerous social, economic, and political problems. These problems became the main cause of the high rate of migration. Many citizens, especially young people, were forced to migrate to European countries and beyond in the absence of prospects in Kosovo. Unemployed and employed people migrated in search of a better life. Migration from Kosovo continues to be high to this day. Countries like Germany began issuing work visas to Kosovans after 2005, leading many young people to migrate to Germany. To understand the situation of Kosovan migrants before and after migration, the study (N = 350) aimed to investigate the situation of unemployment, employment, and satisfaction with pre - and post-migration earnings. The results show that around 75% of Kosovan migrants were unemployed before migrating and about 50% of those who were employed had low monthly incomes (up to 200 euros), while in the host society this situation has changed positively. The results indicate that, after the migration to the host society, about 85 % of Kosovan migrants are employed, over 50% have high incomes (around 2000 euros), and about one-third have changed their post-migration occupation.

S2343 Lumen-Apposing Metal Stent for Treatment of Gastro-Jejunal Stricture Following Roux-en-Y Gastric Bypass

INTRODUCTION: Roux-en-Y Gastric Bypass (RYGB) is the second most common bariatric procedure for weight loss. Gastro-Jejunal (GJ) anastomotic strictures occur in up to 7% of cases. Endoscopic balloon dilation is considered the gold standard for GJ strictures; however, in some cases, it fails to deliver. We present a case in which a refractory GJ anastomotic stricture, after RYGB, was resolved by a novel treatment option. CASE DESCRIPTION/METHODS: A 43-year-old female with an extensive past surgical history including a hiatal hernia repair after Lap-Band and a revision of a sleeve for a kink underwent a laparoscopic sleeve gastrectomy conversion to RYGB for severe reflux. Two days after RYGB, the patient developed dysphagia due to GJ stricture for which she had multiple unsuccessful balloon dilation attempts. It was decided that a lumen-apposing metal stent (LAMS) be used to treat this stricture. The stent was then endoscopically removed in 1 month. Upon removal, the GJ anastomosis appeared patent with healthy-appearing efferent and afferent limbs. The patient now has a patent gastrojejunostomy and can tolerate PO intake. DISCUSSION: GJ anastomotic stricture is a potential complication of RYGB. Serial pneumatic dilation is the traditional endoscopic management. Alternatives include the use of a fully covered self-expanding metal stent (fcSEMS), although a high rate of migration has been reported. LAMS has been increasingly used throughout the gastrointestinal tract; its dumbbell shape design minimizes the risk of migration. This case demonstrates the successful use of LAMS in treating GJ stricture after RYGB.Figure 1.: Gastro-Jejunal anastomotic stricture.Figure 2.: Endoscopic view of Lumen-Apposing Metal Stent.Figure 3.: Resolution of Gastro-Jejunal anastomotic stricture.

S2337 Outcomes of Lumen-Apposing Metal Stents (LAMS) in the Management of Colonic Strictures, Leaks, and Fistulae

INTRODUCTION: Benign colonic strictures and fistulae are usually managed surgically. Surgical procedures are more invasive and are associated with significant morbidity and occasional mortality. Endoscopic management of colonic strictures involves balloon dilation, covered metal stent placement. Traditional covered metal stents are associated with high migration rate. Fistulae can be managed endoscopically by placement of over the scope clips (OVESCO) or endoscopic suturing. Endoscopic suturing is technically challenging when the lumen is narrow. Lumen apposing metal stents [LAMS] are short (1 cm long) covered metal stents with a unique shape. LAMS has several advantages, including varying diameter (10mm, 15mm, 20 mm), a saddle-shaped design that decreases migration risk, and an easy deployment system allowing high technical success. Use of LAMS in the management of the upper GI tract strictures has been reported. We aimed to study the safety and efficacy of using LAMS (AXIOS, Boston Scientific, Marlborough, USA) in the treatment of colonic strictures and fistulae. CASE DESCRIPTION/METHODS: We retrospectively reviewed data of 5 patients who had undergone LAMS placement in the colon for strictures, fistulae or leaks in the past one year. Patient demographics, location of the stricture/fistula, previous treatments, indication for the stent, size of the LAMS used, intraprocedural adverse events, post procedural adverse events, follow up data was collected. Our patient sample comprised 3 females and 2 males with an age range of 57 to 81 years. Of the 5 patients, 3 had an anastomotic leak/fistula (AF), while 2 had benign anastomotic strictures (S) in the sigmoid colon. The 20 mm AXIOS was deployed successfully in all patients without any evidence of bleeding or stent mal-deployment. Of the 5 patients, two had failed prior intervention with either an Ovesco clip closure (2 AF) or balloon dilatation (1 S). Follow up data is available in 4 patients (2 AF and 2 S): all had resolution of the strictures/fistulae. One is awaiting follow up. See Table 1 for details. DISCUSSION: LAMS can be successfully utilized as a safe and effective alternative in the management of short segment benign colon strictures and fistulae. Further prospective studies are needed to assess the outcomes of LAMS use in the colon.Table 1.: Patient demographics and Clinical information- AXIOS for management of Colon strictures and leaks.

Dual-action of thermoresponsive gels containing DsiRNA-loaded gold nanoparticles for diabetic wound therapy: Characterization, in vitro safety and healing efficacy

Diabetic wounds are difficult to treat due to multiple causes, including reduced blood flow and bacterial infections. Reduced blood flow is associated with overexpression of prostaglandin transporter (PGT) gene, induced by hyperglycaemia which causing poor vascularization and healing of the wound. Recently, gold nanoparticles (AuNPs) have been biosynthesized using cold and hot sclerotium of Lignosus rhinocerotis extracts (CLRE and HLRE, respectively) and capped with chitosan (CS) to produce biocompatible antibacterial nanocomposites. The AuNPs have shown to produce biostatic effects against selected gram positive and negative bacteria. Therefore, in this study, a dual therapy for diabetic wound consisting Dicer subtract small interfering RNA (DsiRNA) and AuNPs was developed to improve vascularization by inhibiting PGT gene expression and preventing bacterial infection, respectively. The nanocomposites were incorporated into thermoresponsive gel, made of pluronic and polyethylene glycol. The particle size of AuNPs synthesized using CLRE (AuNPs-CLRE) and HLRE (AuNPs-HLRE) was 202 ± 49 and 190 ± 31 nm, respectively with positive surface charge (+30 to + 45 mV). The thermoresponsive gels containing DsiRNA-AuNPs gelled at 32 ± 1 °C and released the active agents in sufficient amount with good texture and rheological profiles for topical application. DsiRNA-AuNPs and those incorporated into thermoresponsive pluronic gels demonstrated high cell viability, proliferation and cell migration rate via in vitro cultured cells of human dermal fibroblasts, indicating their non-cytotoxicity and wound healing properties. Taken together, the thermoresponsive gels are expected to be useful as a potential dressing that promotes healing of diabetic wounds.

Optimization of the grain boundary character distribution of pure copper by low-strain thermomechanical processing

Abstract Although thermomechanical processing has been widely used in grain boundary engineering, the relationship between thermomechanical parameters and grain boundary character distribution is still not well understood. In the present study, electron backscatter diffraction was used to study the grain boundary character distribution in pure copper after lowstrain thermomechanical treatments. It was found that the low-R coincidence site lattice frequency and grain size decreases in the following sequence, 10% compression > 15% compression > 5% compression, except for 700 0C. During thermomechanical treatments of copper, strain-induced grain boundary migration and grain growth may occur during annealing of 5% compressed copper, and recrystallization dominates during annealing of 15% compressed copper, while the annealing mechanism of 10% compressed copper changes from strain-induced grain boundary migration and grain growth to recrystallization when the annealing temperature exceeds 600 0C. The results indicated that during single-step low-strain thermomechanical treatments, straininduced grain boundary migration and grain growth would gradually change to recrystallization with the increase of pre-deformation level and annealing temperature. Among the three mechanisms, strain-induced grain boundary migration seems to be more effective than recrystallization and grain growth in the optimization of grain boundary character distribution, and it is suggested that this is due to the high boundary migration rate of strain-induced grain boundary migration.

Preparation of potato flour by freeze-thaw pretreatment: Effect of different thawing methods on hot-air drying process and physicochemical properties

Freeze-thaw (FT) pretreatment was applied to hot-air drying of cooked-potato flour preparation. Five thawing methods including air thawing (AT, 25 °C), running water thawing (RWT, 25 °C), refrigerator thawing (RT, 4 °C), ultrasonic-assisted thawing (UT) and microwave thawing (MT) were individually used. The rehydration rate, total energy consumption, starch composition, pasting characteristics, rheological and thermal properties of potato flour were evaluated. FT pretreatment improved the air-drying rate and shortened the drying time. RWT obtained the largest drying rate and reduced total energy consumption by up to 32.9%. The improvement of air-drying was attributed to lower initial water content and high moisture migration rate in freeze-thawed potato slices. Furthermore, FT pretreatment decreased the amylose to amylopectin ratio and increased the relative crystallinity and resulted in alteration of rheological and thermal properties of potato flour. The observed higher pasting temperature, final viscosity, setback value, gelatinization enthalpy (ΔH), elastic modulus, and viscosity modulus were associated with the decrease in amylose to amylopectin ratio and increase of starch crystallinity. Overall, FT pretreatment is effective to shorten the subsequent drying time of potato flour having higher relative crystallinity, with lower energy consumption.

Affordable Housing and Cost Reduction Factors for Affordable Housing

"The importance of affordable housing has emerged recently due to the suffering of most urban areas and developing countries in particular from the high rates of population growth and migration to cities, in addition to the conditions of poverty and war, which led to the loss of many families for their housing units. (The need for a comprehensive knowledge framework clarifying the concept of affordable housing, choosing the best housing type and cost reduction factors (facilitation aspects) at the local level in light of the country’s urgent need for affordable housing.) Accordingly, the objective of the research was to: (Provide a comprehensive knowledge framework that clarifies the concept of affordable housing and choose the best housing type and cost reduction factors (facilitation aspects) in accordance with local privacy). The research hypothesis : (The factors and means of reducing housing costs (aspects of facilitation mentioned in the research) at the two levels (housing complex and housing unit) as well as choosing the housing style (vertical or horizontal) a role in achieving the principle of affordable housing and solving a large part of the housing crisis. For the purpose of solving this problem, three phases were identified, including the construction of a theoretical framework, which included (4) vocabularies (characteristics of affordable housing, cost-raising factors, cost reduction factors, and dimensions of affordable housing). This is followed by the application of these vocabulary by electing two local samples. The extent of facilitation and comparability between them. The results showed that the vertical building pattern (residential buildings) is characterized by its lack of large areas of residential land, thus it is characterized by being less expensive than horizontal construction. This does not prevent investors from building high-quality residential towers targeting the rich."

Optimization of the grain boundary character distribution of pure copper by low-strain thermomechanical processing

Abstract Although thermomechanical processing has been widely used in grain boundary engineering, the relationship between thermomechanical parameters and grain boundary character distribution is still not well understood. In the present study, electron backscatter diffraction was used to study the grain boundary character distribution in pure copper after lowstrain thermomechanical treatments. It was found that the low-R coincidence site lattice frequency and grain size decreases in the following sequence, 10% compression > 15% compression > 5% compression, except for 700 0C. During thermomechanical treatments of copper, strain-induced grain boundary migration and grain growth may occur during annealing of 5% compressed copper, and recrystallization dominates during annealing of 15% compressed copper, while the annealing mechanism of 10% compressed copper changes from strain-induced grain boundary migration and grain growth to recrystallization when the annealing temperature exceeds 600 0C. The results indicated that during single-step low-strain thermomechanical treatments, straininduced grain boundary migration and grain growth would gradually change to recrystallization with the increase of pre-deformation level and annealing temperature. Among the three mechanisms, strain-induced grain boundary migration seems to be more effective than recrystallization and grain growth in the optimization of grain boundary character distribution, and it is suggested that this is due to the high boundary migration rate of strain-induced grain boundary migration.

The Impact of Rapid Population Growth on Economic Growth: Evidence From Ethiopia

Rapid population growth is increasing from time to time as a result of high fertility and migration rate. This has a greater impact on the quality life of the society, in case of increasing number of unemployed peoples, lack of job opportunity, decrease in land share, infrastructure and so on. The objective of this study aimed to examine the impact of rapid population on economic growth of Ethiopia country by employing Autoregressive distributed lag model for the time period spanning from 1975 to 2019. The variables used in model were, population, consumer price index, gross investment proxied by gross capital formation and trade openness as explanatory variables and RGDP proxy for economic growth used as dependent variable. To check stationarity properties of the data augmented dickey fuller unit root test was used and the result indicates all the variables are non-stationary at level and become stationary at first difference. Regarding cointegration test, ARDL bound test used to test the existence of long-run association among the variables and the result confirmed that there is long run relationship among RGDP and explanatory variables. The empirical result obtained from ARDL Model revealed that gross capital formation and consumer price index have found to be positive and statistical significant impact on RGDP in both short run and long run where as our variable of interest meaning population growth is negatively affecting real GDP in the short run but, in the long run it is found to be positive and statistical significantly affecting economic growth. Keywords : population growth, economic growth, ARDL, Bound test, Ethiopia DOI: 10.7176/JESD/11-15-02 Publication date: August 31 st 2020

Ancient globetrotters-connectivity and putative native ranges of two cosmopolitan biofouling amphipods.

The geographic distributions of some coastal marine species have appeared as cosmopolitan ever since they were first scientifically documented. In particular, for many benthic species that are associated with anthropogenic substrata, there is much speculation as to whether or not their broad distributions can be explained by natural mechanisms of dispersal. Here, we focused on two congeneric coastal crustaceans with cosmopolitan distributions—the tube-dwelling amphipods Jassa marmorata and Jassa slatteryi. Both species are common elements of marine biofouling on nearly all kinds of artificial hard substrata in temperate to warm seas. We hypothesized that the two species’ modern occurrences across the oceans are the result of human shipping activities that started centuries ago. Mitochondrial DNA sequences of the CO1 fragment of specimens from distinct marine regions around the world were analysed, evaluating genetic structure and migration models and making inferences on putative native ranges of the two Jassa species. Populations of both species exhibited considerable genetic diversity with differing levels of geographic structure. For both species, at least two dominant haplotypes were shared among several geographic populations. Rapid demographic expansion and high migration rates between geographically distant regions support a scenario of ongoing dispersal all over the world. Our findings indicate that the likely former native range of J. marmorata is the Northwest Atlantic, whereas the likely former native range of J. slatteryi is the Northern Pacific region. As corroborated by the genetic connectivity between populations, shipping still appears to be the more successful vector of the two species’ dispersal when compared to natural mechanisms. Historical invasion events that likely started centuries ago, along with current ongoing dispersal, confirm these species’ identities as true “neocosmopolitans”.

Temporal migration rates affect the genetic structure of populations in the biennial Erysimum mediohispanicum with reproductive asynchrony.

Migration is a process with important implications for the genetic structure of populations. However, there is an aspect of migration seldom investigated in plants: migration between temporally isolated groups of individuals within the same geographic population. The genetic implications of temporal migration can be particularly relevant for semelparous organisms, which are those that reproduce only once in a lifetime after a certain period of growth. In this case, reproductive asynchrony in individuals of the same population generates demes of individuals differing in their developmental stage (non-reproductive and reproductive). These demes are connected by temporal migrants, that is, individuals that become annually asynchronous with respect to the rest of individuals of their same deme. Here, we investigated the extent of temporal migration and its effects on temporal genetic structure in the biennial plant Erysimum mediohispanicum. To this end, we conducted two independent complementary approaches. First, we empirically estimated temporal migration rates and temporal genetic structure in four populations of E. mediohispanicum during three consecutive years using nuclear microsatellites markers. Second, we developed a demographic genetic simulation model to assess genetic structure for different migration scenarios differing in temporal migration rates and their occurrence probabilities. We hypothesized that genetic structure decreased with increasing temporal migration rates due to the homogenizing effect of migration. Empirical and modelling results were consistent and indicated a U-shape relationship between genetic structure and temporal migration rates. Overall, they indicated the existence of temporal genetic structure and that such genetic structure indeed decreased with increasing temporal migration rates. However, genetic structure increased again at high temporal migration rates. The results shed light into the effects of reproductive asynchrony on important population genetic parameters. Our study contributes to unravel the complexity of some processes that may account for genetic diversity and genetic structure of natural populations.

Habitat availability and environmental preference drive species range shifts in concordance with climate change

AbstractAimA progressive increase in air temperature is recognized as the most important mechanistic driver of species range shifts. However, only a few studies have simultaneously considered the influence of both extrinsic and intrinsic mechanistic drivers; there are still no studies on the roles of extrinsic and intrinsic drivers that regulate such species changes. We investigated how species will shift their geographical ranges to cope with future climate change and analysed the relative importance of the mechanistic drivers in governing species range shifts.LocationSixteen countries in South, West and North Europe.MethodsWe used ensemble species distribution models on the European continental scale to predict 105 odonate species in response to climate change in the future decades until 2080s under three emission scenarios. We evaluated the projected changes in four community metrics (distribution area, optimum position, leading edge and trailing edge) and investigated how these changes are driven by extrinsic and intrinsic factors.ResultsThe odonate species were predicted to shift their range margins poleward, with a higher migration rate towards the trailing edge (2.38‒10.34 km/year) than the leading edge (1.13‒2.00 km/year). Contrary to the assumption that the response of the odonate species to climate change will linearly accelerate over time, the distribution areas of odonate species were predicted to increase until 2050s and then decline until 2080s under RCP 2.6 (representative concentration pathway). However, their distributions under RCP 4.5 and RCP 8.5 were predicted to decrease over time, with a higher rate under RCP 8.5. Overall, environmental preference and habitat override dispersal ability govern the range shift of odonate species.Main conclusionsQuantifying the relative importance of extrinsic and intrinsic factors across a large spatial scale under different emission scenarios can help understand the mechanistic processes to facilitate species range shifts.

Search for potential K ion battery cathodes by first principles

Abstract An important challenge facing K-ion batteries lies in exploring earth-abundant and safe cathode materials that can provide high capacity with high migration rate of K ions. Here, we propose a simple and efficient method for searching potential K cathode materials with first principles calculations. Our screening is based on combinations of weight capacity, K ion occupation ratio, volume change per K, and valence limit. With this screening method we predicted a series of potential K ions cathodes with favorable electrochemical performance, such as K2VPO4CO3-like structures with 1D diffusion channels, 3D channel structures K2CoSiO4, layered materials KCoO2, KCrO2, KVF4 and K5V3F14, and others. These potential cathodes have small volume changes, suitable voltage, and high capacity, with small diffusion barriers. They may be useful in K-ion batteries with high energy density and rate performance.

The cultural identity of first-generation immigrant children and youth: Insights from a meta-analysis

ABSTRACT In a globalized world with high rates of migration, identification with one’s culture of origin and one’s new cultural environment is a key and sometimes conflicted issue. Focusing on the growing population of first-generation immigrant children and youth, this study reviewed previous literature, using meta-analysis to investigate core factors affecting identity development. A search of databases yielded 3,636 English-language articles published between 1987 and 2017, of which only 24 met all eligibility criteria and were analyzed in depth. Random-effects analysis revealed that young first-generation immigrants identified moderately with their culture of origin and that their identification with the residence country was, by comparison, weaker. Identity was found to be moderated by core demographic and migration-related factors. The implications of the findings and methodological challenges in the field are discussed.

Quantifying Coastal Fluvial Morphodynamics Over the Last 100 Years on the Lower Rio Grande, USA and Mexico

AbstractDownstream changes in fluvial channel morphology are commonly observed in association with the backwater zone, where rivers transition from quasi‐uniform flow with normal‐flow depth to gradually varying flow. This transition is linked to changes in channel morphology and mobility and resulting fluvial stratigraphy. However, the majority of systems studied to date are perennial rivers with relatively consistent flow conditions. Here we investigate the evolution of a large river with significant flood‐to‐baseflow variability as it transverses and builds a large delta. We provide the first comprehensive study of the morphology and morphodynamics of the lower Rio Grande, a major continental drainage system that enters the western Gulf of Mexico. We quantify the morphology of the current Rio Grande channel and document spatial trends in channel geometry and kinematics using lidar, historical surveys, and hydrographic analysis. The modern Rio Grande channel morphology does not significantly vary toward the coast. Rather, the channel width, levee, and bed slopes remain nearly constant for ~200 river km. We find historical migration rates between 10 and 100 m/yr with no significant reduction toward the coast in contrast to previously studied systems. We propose that this invariant channel geometry and sustained high migration rates are signatures of the channel not requiring adjustment within the lower coastal reach to accommodate baseflow conditions, and the channel remains continuously adjusted solely to peak flow conditions.

Is internal migration declining in Iceland? Intensities, geographical patterns and population composition 1986–2017

AbstractThe Nordic countries have higher rates of internal migration than most other Western societies and have not always shared in the declines noted in other countries. This paper examines migration in Iceland during the period 1986–2017 to add to the wider international literature on migration trends. Compared with its Nordic neighbours, Iceland has the highest rates of internal migration and currently also the greatest porosity in terms of international inflows and outflows. The main focus is on migration flows between the Reykjavík capital area—the only city in the country—the nearby exurban regions on the one hand and the more distant provinces at the other hand. We show that, despite continued high aggregate migration rates, there has been a slight but long‐term downward trend in all moves. We also indicate that migration rates are highly sensitive to cyclic economic fluctuations. Migration between the Reykjavík capital area and its surrounding exurban regions is characterised by increasing mobility during economic booms but the Great Recession starting in 2008 led to a fall in migration. However, the slight decline in overall internal migration in Iceland since the 1990s can almost exclusively be attributed to the decline in migration from the provinces to the Reykjavík capital area, which predates the 2008 Great Recession.

Using lattice SIS epidemiological model with clustered treatment to investigate epidemic control

In epidemic control, how the size of treatment blocks influences the disease is a very interesting problem. Here, we construct an SIS model with spatially clustered treatment blocks using cellular automata and pair approximation to investigate the disease control and optimal arrangement of treatment blocks. On a same treatment intensity, the treatment blocks are built randomly and the individuals in the treatment blocks are cured in the next interval. The migration and neighboring structures are also considered in this model. We find that the size of treatment blocks will influence the control of disease. The bigger size of treatment blocks is more effective in epidemic control. The results obtained by lattice simulations and pair approximation respectively are consistent. On the same treatment arrange, higher migration rate has completely different influence on the epidemic depending on different neighboring structures. Besides, in different neighboring structures, both infected and susceptible populations will get clustered under the treatment blocks. Meanwhile, the neighboring structures can influence the degree of aggregation and the bigger treatment blocks can promote the aggregation compared to the smaller ones. The results here are significant for the control of epidemic diseases, especially when available medical resources are limited.