Effects of hatchery fish density on emigration, growth, survival, and predation risk of natural steelhead parr in an experimental stream channel

USGS Publications Warehouse

Tatara, Christopher P.; Riley, Stephen C.; Berejikian, Barry A.

2011-01-01

Hatchery supplementation of steelhead Oncorhynchus mykiss raises concerns about the impacts on natural populations, including reduced growth and survival, displacement, and increased predation. The potential risks may be density dependent.We examined how hatchery stocking density and the opportunity to emigrate affect the responses of natural steelhead parr in an experimental stream channel and after 15 d found no density-dependent effects on growth, emigration, or survival at densities ranging from 1-6 hatchery parr/m2. The opportunity for steelhead parr to emigrate reduced predation by coastal cutthroat trout O. clarkii clarkii on both hatchery and natural steelhead parr. The cutthroat trout exhibited a type-I functional response (constant predation rate with increased prey density) for the hatchery and composite populations. In contrast, the predation rate on natural parr decreased as hatchery stocking density increased. Supplementation with hatchery parr at any experimental stocking density reduced the final natural parr density. This decline was explained by increased emigration fromthe supplemented groups. Natural parr had higher mean instantaneous growth rates than hatchery parr. The proportion of parr emigrating decreased as parr size increased over successive experimental trials. Smaller parr had lower survival and suffered higher predation. The final density of the composite population, a measure of supplementation effectiveness, increased with the hatchery steelhead stocking rate. Our results indicate that stocking larger hatchery parr (over 50 d postemergence) at densities within the carrying capacity would have low short-term impact on the growth, survival, and emigration of natural parr while increasing the density of the composite population; in addition, a stocking density greater than 3 fish/m2 might be a good starting point for the evaluation of parr stocking in natural streams.

Activation of calcitonin gene-related peptide receptor during ozone inhalation contributes to airway epithelial injury and repair.

PubMed

Oslund, Karen L; Hyde, Dallas M; Putney, Leialoha F; Alfaro, Mario F; Walby, William F; Tyler, Nancy K; Schelegle, Edward S

2009-10-01

The authors investigated the importance of the neuropeptide, calcitonin gene-related peptide (CGRP), in epithelial injury, repair, and neutrophil emigration after ozone exposure. Wistar rats were administered either a CGRP-receptor antagonist (CGRP(8-37)) or saline and exposed to 8 hours of 1-ppm ozone or filtered air with an 8-hour postexposure period. Immediately after exposure, ethidium homodimer was instilled into lungs as a marker of necrotic airway epithelial cells. After fixation, airway dissected lung lobes were stained for 5'-bromo-2'-deoxyuridine, a marker of epithelial proliferation. Positive epithelial cells were quantified in specific airway generations. Rats treated with CGRP(8-37) had significantly reduced epithelial injury in terminal bronchioles and reduced epithelial proliferation in proximal airways and terminal bronchioles. Bronchoalveolar lavage and sections of terminal bronchioles showed no significant difference in the number of neutrophils emigrating into airways in CGRP(8-37)-treated rats. The airway epithelial cell line, HBE-1, showed no difference in the number of oxidant stress positive cells during exposure to hydrogen peroxide and a range of CGRP(8-37) doses, demonstrating no antioxidant effect of CGRP(8-37). We conclude that activation of CGRP receptors during ozone inhalation contributes to airway epithelial injury and subsequent epithelial proliferation, a critical component of repair, but does not influence neutrophil emigration into airways.

Emigration from Nepal: some major issues.

PubMed

Singh, M L

1997-07-01

This study examined emigration from Nepal during 1952-91. Data were obtained from census records decennially. Records indicate that the volume of emigration amounted to about 2.39% of total population in 1952-53, and 3.58% in 1991. The level of emigration rose from 198,120 persons to 658,290. Emigrants are persons who were absent from their home for more than 6 months due to tourism, pilgrimage, business trips, studies, employment, or permanent migration. Most emigrants return home after several months or years. A recent survey finds that 14.1% returned after more than 5 years. The Nepal model of migration is different from conventional or Marxist models. For example, landlessness or near landlessness are not the primary reasons for migration. The recent emigration to Arab countries is driven by the desire for better income. Emigrants pay handsomely to go abroad for work (Rs. 85,000). Nepalese emigrate to Australia and the US for a better income and a better life. The proportion of female emigrants was 6.23% of total emigrants to Arab countries, and 16.2% to India. 31% of emigrants were females who emigrated to North America, and 29% emigrated to European countries. Emigrants to Arab countries were likely to return home. Emigrants to North America and Europe were likely to be permanent migrants. The author prefers Mellassoux's (1981) model that says that Nepal is losing manpower during their most productive years. Remittances do not offset the loss. Government costs are incurred for supporting education abroad, benefits in old age and for youth, and the spread of sexually transmitted diseases.

Enhanced clonal burst size corrects an otherwise defective memory response by CD8+ recent thymic emigrants

PubMed Central

Deets, Katherine A.; Berkley, Amy M.; Bergsbaken, Tessa; Fink, Pamela J.

2016-01-01

The youngest peripheral T cells (recent thymic emigrants or RTEs) are functionally distinct from naïve T cells that have completed post-thymic maturation. We now assess the RTE memory response, and find that RTEs produced less granzyme B than their mature counterparts during infection, but proliferated more and therefore generated equivalent target killing in vivo. After infection, RTE numbers contracted less dramatically than those of mature T cells, but RTEs were delayed in their transition to central memory, displaying impaired expression of CD62L, IL-2, Eomesodermin, and CXCR4, which resulted in impaired bone marrow localization. RTE-derived and mature memory cells expanded equivalently during rechallenge, indicating the robust proliferative capacity of RTEs was maintained independently of central memory phenotype. Thus, the diminished effector function and delayed central memory differentiation of RTE-derived memory cells are counterbalanced by their increased proliferative capacity, driving the efficacy of the RTE response to that of mature T cells. PMID:26873989

Cutting Edge: Enhanced Clonal Burst Size Corrects an Otherwise Defective Memory Response by CD8+ Recent Thymic Emigrants.

PubMed

Deets, Katherine A; Berkley, Amy M; Bergsbaken, Tessa; Fink, Pamela J

2016-03-15

The youngest peripheral T cells (recent thymic emigrants [RTEs]) are functionally distinct from naive T cells that have completed postthymic maturation. We assessed the RTE memory response and found that RTEs produced less granzyme B than their mature counterparts during infection but proliferated more and, therefore, generated equivalent target killing in vivo. Postinfection, RTE numbers contracted less dramatically than those of mature T cells, but RTEs were delayed in their transition to central memory, displaying impaired expression of CD62L, IL-2, Eomesodermin, and CXCR4, which resulted in impaired bone marrow localization. RTE-derived and mature memory cells expanded equivalently during rechallenge, indicating that the robust proliferative capacity of RTEs was maintained independently of central memory phenotype. Thus, the diminished effector function and delayed central memory differentiation of RTE-derived memory cells are counterbalanced by their increased proliferative capacity, driving the efficacy of the RTE response to that of mature T cells. Copyright © 2016 by The American Association of Immunologists, Inc.

Recent thymic emigrants and mature naive T cells exhibit differential DNA methylation at key cytokine loci.

PubMed

Berkley, Amy M; Hendricks, Deborah W; Simmons, Kalynn B; Fink, Pamela J

2013-06-15

Recent thymic emigrants (RTEs) are the youngest T cells in the lymphoid periphery and exhibit phenotypic and functional characteristics distinct from those of their more mature counterparts in the naive peripheral T cell pool. We show in this study that the Il2 and Il4 promoter regions of naive CD4(+) RTEs are characterized by site-specific hypermethylation compared with those of both mature naive (MN) T cells and the thymocyte precursors of RTEs. Thus, RTEs do not merely occupy a midpoint between the thymus and the mature T cell pool, but represent a distinct transitional T cell population. Furthermore, RTEs and MN T cells exhibit distinct CpG DNA methylation patterns both before and after activation. Compared with MN T cells, RTEs express higher levels of several enzymes that modify DNA methylation, and inhibiting methylation during culture allows RTEs to reach MN T cell levels of cytokine production. Collectively, these data suggest that the functional differences that distinguish RTEs from MN T cells are influenced by epigenetic mechanisms and provide clues to a mechanistic basis for postthymic maturation.

[Regulation of age-dependent phenomena. Influence of C6-substituted purines on cell aggregation and cell migration in primary cultures of lense epithelial cells].

PubMed

Glässer, D; Iwig, M; Weber, E

1975-01-01

The existence of an age dependent latent period of cell emigration has been proved in the primary culture of epithelial cells of bovine lenses. The previously described aggregation phenomenon as well as the latent period of the cell emigration increase with the age of the sponsor animals. Extracellular adenine and other C6-substituted purines, isolated from the cells themselves and added to the medium, act the same way on the lens cells in the primary culture as the increasing age of the sponsor animals. Adenine stimulates cell aggregation and inhibits the adhesion of the cells to the substratum, the cell flattening and the cell migration. The adenine action has been proved down to a concentration of 3 X 10(-6) M. During the primary culture, the lens cells gradually los the adenine sensitivity. The adenine action also occurs on single cells, isolated by trypsination, it differs from the reaction of ouabain and can be removed at low concentration by washing procedures. The results favour the suggestion C6-substituted purines to be involved in cell ageing.

Cutting Edge: Defective Aerobic Glycolysis Defines the Distinct Effector Function in Antigen-Activated CD8+ Recent Thymic Emigrants.

PubMed

Cunningham, Cody A; Bergsbaken, Tessa; Fink, Pamela J

2017-06-15

Recent thymic emigrants (RTEs) are the youngest peripheral T cells that have completed thymic selection and egress to the lymphoid periphery. RTEs are functionally distinct from their more mature but still naive T cell counterparts, because they exhibit dampened proliferation and reduced cytokine production upon activation. In this article, we show that, compared with more mature but still naive T cells, RTEs are impaired in their ability to perform aerobic glycolysis following activation. Impaired metabolism underlies the reduced IFN-γ production observed in activated RTEs. This failure to undergo Ag-induced aerobic glycolysis is caused by reduced mTORC1 activity and diminished Myc induction in RTEs. Critically, exogenous IL-2 restores Myc expression in RTEs, driving aerobic glycolysis and IFN-γ production to the level of mature T cells. These results reveal a previously unknown metabolic component to postthymic T cell maturation. Copyright © 2017 by The American Association of Immunologists, Inc.

MHC drives TCR repertoire shaping, but not maturation, in recent thymic emigrants.

PubMed

Houston, Evan G; Fink, Pamela J

2009-12-01

After developing in the thymus, recent thymic emigrants (RTEs) enter the lymphoid periphery and undergo a maturation process as they transition into the mature naive (MN) T cell compartment. This maturation presumably shapes RTEs into a pool of T cells best fit to function robustly in the periphery without causing autoimmunity; however, the mechanism and consequences of this maturation process remain unknown. Using a transgenic mouse system that specifically labels RTEs, we tested the influence of MHC molecules, key drivers of intrathymic T cell selection and naive peripheral T cell homeostasis, in shaping the RTE pool in the lymphoid periphery. We found that the TCRs expressed by RTEs are skewed to longer CDR3 regions compared with those of MN T cells, suggesting that MHC does streamline the TCR repertoire of T cells as they transition from the RTE to the MN T cell stage. This conclusion is borne out in studies in which the representation of individual TCRs was followed as a function of time since thymic egress. Surprisingly, we found that MHC is dispensable for the phenotypic and functional maturation of RTEs.

Spatially explicit dynamic N-mixture models

USGS Publications Warehouse

Zhao, Qing; Royle, Andy; Boomer, G. Scott

2017-01-01

Knowledge of demographic parameters such as survival, reproduction, emigration, and immigration is essential to understand metapopulation dynamics. Traditionally the estimation of these demographic parameters requires intensive data from marked animals. The development of dynamic N-mixture models makes it possible to estimate demographic parameters from count data of unmarked animals, but the original dynamic N-mixture model does not distinguish emigration and immigration from survival and reproduction, limiting its ability to explain important metapopulation processes such as movement among local populations. In this study we developed a spatially explicit dynamic N-mixture model that estimates survival, reproduction, emigration, local population size, and detection probability from count data under the assumption that movement only occurs among adjacent habitat patches. Simulation studies showed that the inference of our model depends on detection probability, local population size, and the implementation of robust sampling design. Our model provides reliable estimates of survival, reproduction, and emigration when detection probability is high, regardless of local population size or the type of sampling design. When detection probability is low, however, our model only provides reliable estimates of survival, reproduction, and emigration when local population size is moderate to high and robust sampling design is used. A sensitivity analysis showed that our model is robust against the violation of the assumption that movement only occurs among adjacent habitat patches, suggesting wide applications of this model. Our model can be used to improve our understanding of metapopulation dynamics based on count data that are relatively easy to collect in many systems.

Recent thymic emigrants and mature naïve T cells exhibit differential DNA methylation at key cytokine loci

PubMed Central

Berkley, Amy M.; Hendricks, Deborah W.; Simmons, Kalynn B.; Fink, Pamela J.

2013-01-01

Recent thymic emigrants (RTEs) are the youngest T cells in the lymphoid periphery, and exhibit phenotypic and functional characteristics distinct from those of their more mature counterparts in the naïve peripheral T cell pool. We show here that the Il2 and Il4 promoter regions of naïve CD4+ RTEs are characterized by site-specific hypermethylation compared to those of both mature naïve (MN) T cells and the thymocyte precursors of RTEs. Thus, RTEs do not merely occupy a midpoint between the thymus and the mature T cell pool, but represent a distinct transitional T cell population. Furthermore, RTEs and MN T cells exhibit distinct CpG DNA methylation patterns both before and after activation. Compared to MN T cells, RTEs express higher levels of several enzymes that modify DNA methylation, and inhibiting methylation during culture allows RTEs to reach MN T cell levels of cytokine production. Collectively, these data suggest that the functional differences that distinguish RTEs from MN T cells are influenced by epigenetic mechanisms and provide clues to a mechanistic basis for post-thymic maturation. PMID:23686491

CD8+ recent thymic emigrants exhibit increased responses to low affinity ligands and improved access to peripheral sites of inflammation

PubMed Central

Berkley, Amy M.; Fink, Pamela J.

2014-01-01

To explore the TCR sensitivity of recent thymic emigrants (RTEs), we triggered T cells with altered peptide ligands (APLs). Upon peptide stimulation in vitro, RTEs exhibited increased TCR signal transduction, and following infection in vivo with APL-expressing bacteria, CD8 RTEs expanded to a greater extent in response to low affinity antigens than their mature T cell counterparts. RTEs skewed to short-lived effector cells in response to all APLs but were also characterized by diminished cytokine production. RTEs responding to infection expressed increased levels of VLA-4, with consequent improved entry into inflamed tissue and pathogen clearance. These positive outcomes were offset by the capacity of RTEs to elicit autoimmunity. Overall, salient features of CD8 RTE biology should inform strategies to improve neonatal vaccination and therapies for cancer and HIV, as RTEs make up a large proportion of the T cells in lymphodepleted environments. PMID:25172492

Recent thymic emigrants are tolerized in the absence of inflammation

PubMed Central

Friesen, Travis J.; Ji, Qingyong

2016-01-01

T cell development requires a period of postthymic maturation. Why this is the case has remained a mystery, particularly given the rigors of intrathymic developmental checkpoints, successfully traversed by only ∼5% of thymocytes. We now show that the first few weeks of T cell residence in the lymphoid periphery define a period of heightened susceptibility to tolerance induction to tissue-restricted antigens (TRAs), the outcome of which depends on the context in which recent thymic emigrants (RTEs) encounter antigen. After encounter with TRAs in the absence of inflammation, RTEs exhibited defects in proliferation, diminished cytokine production, elevated expression of anergy-associated genes, and diminished diabetogenicity. These properties were mirrored in vitro by enhanced RTE susceptibility to regulatory T cell–mediated suppression. In the presence of inflammation, RTEs and mature T cells were, in contrast, equally capable of inducing diabetes, proliferating, and producing cytokines. Thus, recirculating RTEs encounter TRAs during a transitional developmental stage that facilitates tolerance induction, but inflammation converts antigen-exposed, tolerance-prone RTEs into competent effector cells. PMID:27139493

Cutting edge: CD8+ recent thymic emigrants exhibit increased responses to low-affinity ligands and improved access to peripheral sites of inflammation.

PubMed

Berkley, Amy M; Fink, Pamela J

2014-10-01

To explore the TCR sensitivity of recent thymic emigrants (RTEs), we triggered T cells with altered peptide ligands (APLs). Upon peptide stimulation in vitro, RTEs exhibited increased TCR signal transduction, and following infection in vivo with APL-expressing bacteria, CD8 RTEs expanded to a greater extent in response to low-affinity Ags than did their mature T cell counterparts. RTEs skewed to short-lived effector cells in response to all APLs but also were characterized by diminished cytokine production. RTEs responding to infection expressed increased levels of VLA-4, with consequent improved entry into inflamed tissue and pathogen clearance. These positive outcomes were offset by the capacity of RTEs to elicit autoimmunity. Overall, salient features of CD8 RTE biology should inform strategies to improve neonatal vaccination and therapies for cancer and HIV, because RTEs make up a large proportion of the T cells in lymphodepleted environments. Copyright © 2014 by The American Association of Immunologists, Inc.

Recent thymic emigrants are preferentially incorporated only into the depleted T-cell pool.

PubMed

Houston, Evan G; Higdon, Lauren E; Fink, Pamela J

2011-03-29

Recent thymic emigrants (RTEs) are the youngest subset of peripheral T cells, and they differ functionally and phenotypically from the rest of the naïve T-cell pool. RTEs are present in the peripheral T-cell pool throughout life but are the most common subset of T cells in neonates and adults recovering from lymphoablation. Using a murine model to study the homeostasis of RTEs, we show that under lymphoreplete conditions, RTEs are at a competitive disadvantage to already established mature naïve (MN) T cells. This disadvantage may be caused by a defect in survival, because RTEs may transduce homeostatic signals inefficiently, and their ability to survive is enhanced with increased expression of IL-7 receptor or B-cell lymphoma 2 (Bcl-2). Conversely, under lymphopenic conditions, enhanced proliferation by RTEs allows them to out-compete their MN T-cell counterparts. These results suggest that in times of need, such as in neonates or lymphopenic adults, RTEs perform well to fill the gaps in the peripheral T-cell pool, but when the periphery already is full, many RTEs are not incorporated into the pool of recirculating lymphocytes.

Partitioning loss rates of early juvenile blue crabs from seagrass habitats into mortality and emigration

USGS Publications Warehouse

Etherington, L.L.; Eggleston, D.B.; Stockhausen, W.T.

2003-01-01

Determining how post-settlement processes modify patterns of settlement is vital in understanding the spatial and temporal patterns of recruitment variability of species with open populations. Generally, either single components of post-settlement loss (mortality or emigration) are examined at a time, or else the total loss is examined without discrimination of mortality and emigration components. The role of mortality in the loss of early juvenile blue crabs, Callinectes sapidus, has been addressed in a few studies; however, the relative contribution of emigration has received little attention. We conducted mark-recapture experiments to examine the relative contribution of mortality and emigration to total loss rates of early juvenile blue crabs from seagrass habitats. Loss was partitioned into emigration and mortality components using a modified version of Jackson's (1939) square-within-a-square method. The field experiments assessed the effects of two size classes of early instars (J1-J2, J3-J5), two densities of juveniles (low: 16 m-2, high: 64 m-2), and time of day (day, night) on loss rates. In general, total loss rates of experimental juveniles and colonization rates by unmarked juveniles were extremely high (range = 10-57 crabs m-2/6 h and 17-51 crabs m-2/6 h, for loss and colonization, respectively). Total loss rates were higher at night than during the day, suggesting that juveniles (or potentially their predators) exhibit increased nocturnal activity. While colonization rates did not differ by time of day, J3-J5 juveniles demonstrated higher rates of colonization than J1-J2 crabs. Overall, there was high variability in both mortality and emigration, particularly for emigration. Average probabilities of mortality across all treatment combinations ranged from 0.25-0.67/6 h, while probabilities of emigration ranged from 0.29-0.72/6 h. Although mean mortality rates were greater than emigration rates in most treatments, the proportion of experimental trials in which crab loss from seagrass due to mortality was greater than losses due to emigration was not significantly different from 50%. Thus, mortality and emigration appear to contribute equally to juvenile loss in seagrass habitats. The difference in magnitude (absolute amount of loss) between mean emigration and mean mortality varied between size classes, such that differences between emigration and mortality were relatively small for J1-J2 crabs, but much larger for J3-J5 crabs. Further, mortality rates were density-dependent for J3-J5 juvenile stages but not for J1-J2 crabs, whereas emigration was inversely density-dependent among J3-J5 stages but not for J1-J2 instars. The co-dependency of mortality and emigration suggests that the loss term (emigration or mortality) which has the relatively stronger contribution to total loss may dictate the patterns of loss under different conditions. For older juveniles (J3-J5), emigration may only have a large impact on juvenile loss where densities are low, since the contribution of mortality appears to be much greater than emigration at high densities. The size-specific pattern of density-dependent mortality supports the notion of an ontogenetic habitat shift by early juvenile blue crabs from seagrass to unvegetated habitats, since larger individuals may experience increased mortality at high densities within seagrass beds. Qualitative comparisons between this study and a concurrent study of planktonic emigration of J1-J5 blue crabs (Blackmon and Eggleston, 2001) suggests that benthic emigration among J1-J2 blue crabs was greater than planktonic emigration; for J3-J5 stages benthic and planktonic emigration were nearly equal. This study demonstrates the potentially large role of emigration in recruitment processes and patterns of early juvenile blue crabs, and illustrates how juvenile size, juvenile density, and time of day can affect mortality and emigration rates as well as total loss and colonization. The components of po

Modulation of leukocyte adhesion in rat mesenteric venules by aspirin and salicylate.

PubMed

Asako, H; Kubes, P; Wallace, J; Wolf, R E; Granger, D N

1992-07-01

Erythrocyte velocity, vessel diameter, leukocyte rolling velocity, and number of adherent and emigrated leukocytes were measured in postcapillary venules both before and during superfusion of rat mesentery with either aspirin or sodium salicylate. In some experiments, animals were treated with either a leukotriene (LT)-synthesis inhibitor (L-663,536), an LTD4 antagonist (MK-571), an LTB4 antagonist (SC-41930), misoprostol, or prostaglandin (PG) I2, then the aspirin protocol was repeated. Superfusion of aspirin but not sodium salicylate resulted in increased leukocyte adherence and a reduced leukocyte rolling velocity but did not affect leukocyte emigration. Aspirin-induced leukocyte adhesion was effectively prevented by the LT-synthesis inhibitor and LTB4 antagonist but not by the LTD4 antagonist. Misoprostol and PGI2 also prevented the aspirin-induced adhesion responses. Superfusion of the mesentery with either platelet-activating factor (PAF) or LTB4 enhanced leukocyte adherence and emigration while reducing leukocyte rolling velocity. Sodium salicylate prevented all of the adhesion responses elicited by LTB4. Although salicylate did not affect the PAF-induced leukocyte adherence and rolling responses, it completely prevented the increased leukocyte emigration. These results indicate that aspirin promotes, whereas sodium salicylate inhibits, leukocyte-endothelial cell adhesive interactions at therapeutically relevant concentrations.

The life cycle of Phaeocystis (Prymnesiophycaea): evidence and hypotheses

NASA Astrophysics Data System (ADS)

Rousseau, V.; Vaulot, D.; Casotti, R.; Cariou, V.; Lenz, J.; Gunkel, J.; Baumann, M.

1994-04-01

The present paper reviews the literature related to the life cycle of the prymnesiophyte Phaeocystis and its controlling factors and proposes novel hypotheses based on unpublished observations in culture and in the field. We chiefly refer to P. globosa Scherffel as most of the observations concern this species. P. globosa exhibits a complex alternation between several types of free-living cells (non-motile, flagellates, microzoopores and possibly macrozoospores) and colonies for which neither forms nor pathways have been completely identified and described. The different types of Phaeocystis cells were reappraised on the basis of existing microscopic descriptions complemented by unpublished flow cytometric investigations. This analysis revealed the existence of at least three different types of free-living cells identified on the basis of a combination of size, motility and ploidy characteristics: non-motile cells, flagellates and microzoospores. Their respective function within Phaeocystis life cycle, and in particular their involvement in colony formation is not completely understood. Observational evidence shows that Phaeocystis colonies are initiated at the early stage of their bloom each by one free-living cell. The mechanisms controlling this cellular transformation are still uncertain due to the lack of information on the overwintering Phaeocystis fomms and on the cell type responsible for colony induction. The existence of haploid microzoospores released from senescent colonies gives however some support to sexuality involvement at some stages of colony formation. Once colonies are formed, at least two mechanisms were identified as responsible of the spreading of colony form: colony multiplication by colonial division or budding and induction of new colony from colonial cells released in the external medium after colony disruption. The latter mechanism was clearly identified, involving at least two successive cell differentiations in the following sequence: motility development, subsequent flagella loss and settlement to a surface, mucus secretion and colony formation, colonial cell division and colony growth. Aggregate formation, cell motility development and subsequent emigration from the colonies, release of non-motile cells after colony lysis on the other hand, were identified as characteristics for termination of Phaeocystis colony development. These pathways were shown to occur similarly in natural environments. In the early stages of the bloom however, many recently-formed colonies were found on the setae of Chaetoceros spp, suggesting this diatom could play a key-rôle in Phaeocystis bloom inception. Analysis of the possible environmental factors regulating the transition between the different phases of the life cycle, suggested that nutrient status and requirement of a substrate for attachment of free-living cells would be essential for initiation of the colonial form. Physical constraints obviously would be important in determining colony shape and fragmentation although autogenic factors cannot be excluded. Some evidence exists that nutrients regulate colony division, while temperature and nutrient stress would stimulate cell emigration from the colonies.

T-cell receptor excision circles (TREC) in CD4+ and CD8+ T-cell subpopulations in atopic dermatitis and psoriasis show major differences in the emission of recent thymic emigrants.

PubMed

Just, Helle L; Deleuran, Mette; Vestergaard, Christian; Deleuran, Bent; Thestrup-Pedersen, Kristian

2008-01-01

We used T-cell receptor excision circles (TREC) to evaluate thymic function in adult patients with atopic dermatitis and psoriasis. We observed that men, but not women, with atopic dermatitis had a significantly faster decline in TREC content with increasing age compared with healthy men. In contrast, both men and women with psoriasis had significantly reduced TREC levels, which were, on average, only 30% of that of healthy persons. In atopic dermatitis the levels of TREC declined with increasing levels of IgE, disease intensity and extent of eczema. Furthermore, patients with atopic dermatitis showed signs of altered thymus function, as they had a significantly greater variation in TREC content measured over time than healthy controls, especially within the CD8+ T-cell subpopulation. Because both atopic dermatitis and psoriasis patients have an increased number of T-cells, this indicates that atopic dermatitis patients can have compensatory emissions of thymic emigrants, whereas psoriatic patients do not, thus supporting different thymic function in these two diseases.

Recent thymic emigrants are tolerized in the absence of inflammation.

PubMed

Friesen, Travis J; Ji, Qingyong; Fink, Pamela J

2016-05-30

T cell development requires a period of postthymic maturation. Why this is the case has remained a mystery, particularly given the rigors of intrathymic developmental checkpoints, successfully traversed by only ∼5% of thymocytes. We now show that the first few weeks of T cell residence in the lymphoid periphery define a period of heightened susceptibility to tolerance induction to tissue-restricted antigens (TRAs), the outcome of which depends on the context in which recent thymic emigrants (RTEs) encounter antigen. After encounter with TRAs in the absence of inflammation, RTEs exhibited defects in proliferation, diminished cytokine production, elevated expression of anergy-associated genes, and diminished diabetogenicity. These properties were mirrored in vitro by enhanced RTE susceptibility to regulatory T cell-mediated suppression. In the presence of inflammation, RTEs and mature T cells were, in contrast, equally capable of inducing diabetes, proliferating, and producing cytokines. Thus, recirculating RTEs encounter TRAs during a transitional developmental stage that facilitates tolerance induction, but inflammation converts antigen-exposed, tolerance-prone RTEs into competent effector cells. © 2016 Friesen et al.

[Passport registers: their limits and possibilities for the study of emigration].

PubMed

Baganha, M I

1996-08-01

"There are two main nominal sources of data on Portuguese emigration during the nineteenth and early twentieth centuries: the Rois de Confessados or Rois de Desobriga and the Livros de Registos de Passaportes.... The major question regarding passport registers concerns the level of clandestine emigration. Thus a comparison with U.S. ship lists reveals two different pictures of Portuguese emigration [with regard to] sex ratio, occupations and age distribution. Data obtained point at a larger generalization: sources containing data on legal emigration only do not reflect ¿true' emigration in countries with important clandestine streams." (EXCERPT)

Emigration dynamics in Bangladesh.

PubMed

Mahmood, R A

1995-01-01

This study of emigration dynamics opens by noting that emigration is one of the most dynamic economic and social elements in Bangladesh. The history of emigration from Bangladesh is sketched, and the level and trend of emigration is described for various destinations (especially the UK, the Middle East and North Africa, and Japan) and in terms of the socioeconomic background of migrants, channels of migration, occupations, the potential level of emigration, and applications for US Visas. The next section of the report presents the economic and demographic setting in terms of the gross national and domestic products, quality of life, the size and distribution of the population, the labor force, literacy, unemployment and underemployment, urbanization, internal migration, poverty, and income distribution. The discussion then centers on the sociopolitical setting and such factors as unmet basic human needs, the demand for expatriate workers, and emigration policy. It is concluded that the desperate economic situation in Bangladesh has combined with the demand for expatriate workers and the development of institutions to facilitate emigration. The result is increasing interest in emigration, which is fueled by mass communication highlighting the differences between the quality of life in Bangladesh and abroad.

On the use of secondary capture-recapture samples to estimate temporary emigration and breeding proportions

USGS Publications Warehouse

Kendall, W.L.; Nichols, J.D.; North, P.M.; Nichols, J.D.

1995-01-01

The use of the Cormack- Jolly-Seber model under a standard sampling scheme of one sample per time period, when the Jolly-Seber assumption that all emigration is permanent does not hold, leads to the confounding of temporary emigration probabilities with capture probabilities. This biases the estimates of capture probability when temporary emigration is a completely random process, and both capture and survival probabilities when there is a temporary trap response in temporary emigration, or it is Markovian. The use of secondary capture samples over a shorter interval within each period, during which the population is assumed to be closed (Pollock's robust design), provides a second source of information on capture probabilities. This solves the confounding problem, and thus temporary emigration probabilities can be estimated. This process can be accomplished in an ad hoc fashion for completely random temporary emigration and to some extent in the temporary trap response case, but modelling the complete sampling process provides more flexibility and permits direct estimation of variances. For the case of Markovian temporary emigration, a full likelihood is required.

[The use of personal sources for the study of emigration from Galicia: present state and perspectives].

PubMed

Vazquez Gonzalez, A

1996-08-01

"Spanish sources for the study of emigration are sparse and fragmentary.... Mortgage documents for the payment of ocean transportation enable us to appreciate the spreading action of shipping agents; official listings of draft dodgers reveal that in general the River Plate was a favorite destination, rather than Cuba or Brazil. People from Galicia emigrated from rural origins to urban destinations in America; the analysis of place of birth of emigrants residing in A Coruna at the time of emigration show that there was also, in some cases, a first stage of rural-urban migration within Galicia. The general picture of emigration from Galicia is built [up] through the combination of the existing sources in Spain." (EXCERPT)

A model for estimating passive integrated transponder (PIT) tag antenna efficiencies for interval-specific emigration rates

USGS Publications Warehouse

Horton, G.E.; Dubreuil, T.L.; Letcher, B.H.

2007-01-01

Our goal was to understand movement and its interaction with survival for populations of stream salmonids at long-term study sites in the northeastern United States by employing passive integrated transponder (PIT) tags and associated technology. Although our PIT tag antenna arrays spanned the stream channel (at most flows) and were continuously operated, we are aware that aspects of fish behavior, environmental characteristics, and electronic limitations influenced our ability to detect 100% of the emigration from our stream site. Therefore, we required antenna efficiency estimates to adjust observed emigration rates. We obtained such estimates by testing a full-scale physical model of our PIT tag antenna array in a laboratory setting. From the physical model, we developed a statistical model that we used to predict efficiency in the field. The factors most important for predicting efficiency were external radio frequency signal and tag type. For most sampling intervals, there was concordance between the predicted and observed efficiencies, which allowed us to estimate the true emigration rate for our field populations of tagged salmonids. One caveat is that the model's utility may depend on its ability to characterize external radio frequency signals accurately. Another important consideration is the trade-off between the volume of data necessary to model efficiency accurately and the difficulty of storing and manipulating large amounts of data.

Saquinavir inhibits early events associated with establishment of HIV-1 infection: potential role for protease inhibitors in prevention.

PubMed

Stefanidou, Martha; Herrera, Carolina; Armanasco, Naomi; Shattock, Robin J

2012-08-01

The maturation of newly formed human immunodeficiency virus type 1 (HIV-1) virions is a critical step for the establishment of productive infection. We investigated the potential of saquinavir (SQV), a protease inhibitor (PI) used in highly active antiretroviral therapy (HAART), as a candidate microbicide. SQV inhibited replication of clade B and clade C isolates in a dose-dependent manner in all cellular models tested: PM-1 CD4 T cells, peripheral blood mononuclear cells (PBMCs), monocyte-derived macrophages (MDMs), and immature monocyte-derived dendritic cells (iMDDCs). SQV also inhibited production of infectious virus in cervical, penile, and colorectal explants cocultured with T cells. Moreover, SQV demonstrated inhibitory potency against trans infection of T cells by in vitro-derived dendritic cells and by primary dendritic cells that emigrate from penile and cervical tissue explants. No cellular or tissue toxicity was detected in the presence of SQV, suggesting that this drug could be considered for development as a component of an effective microbicide, capable of blocking viral maturation and transmission of HIV-1 at mucosal surfaces.

[Preventive health control of U. S. emigrants at the beginning of 20th century on the example of hotel "Emigrants" in Rijeka].

PubMed

Rotim Malvić, Jasna

2015-01-01

Rijeka inscribed herself on the list of great European emigration ports like Hamburg, Bremen, Liverpool in the end of the year 1903 when a ship of the British Cunard Line established a travel line from Rijeka to New York. Up to the year 1914, 317639 passengers - emigrants travelled to America from the port of Rijeka. The large flow of people caused problems for the city, for that reason, already in 1906 did the Hungarian ministry of home affairs started the construction of a grandiose building intended for the emigrants. When it was opened in 1908 it was named Hotel Emigrants and had a capacity of 2500 guests. The name Hotel was given to him because of the highest construction and sanitary standards applied during his construction, but also because of comfort provided for the emigrants, large bright dormitories, living rooms, one big and spacious terrace and a number of smaller ones indicated more to a touristic hotel than to a house for emigrants. Health surveillance of emigrants was performed by Dr. David Friedman, Dr. Arturo Jellouscheg and Dr. Emil Tauffer. They were in charge in front of the Maritime Gubernia in Rijeka, the U.S. consulate in Rijeka and the Adria Maritime Society. Although the city authorities and the Hungarian authorities boasted of the hotel and the rigid medical control over immigrants which was done there, American authorities have still often returned some emigrants, at the expense of the company, after inspection at Ellis Island revealing that before landing some individuals are sick.

Brain drain or links to the world: views on emigrants from Singapore.

PubMed

Yap, M T

1994-01-01

"This article will present a general picture of emigration and emigrants from Singapore, with specific references to Australia where the data permit. The first section presents some flow data on the magnitudes of emigration from Singapore.... It is necessary to place this outflow against the background of the constraints imposed by the country's small size. This is discussed in the second section, together with the economic policies and strategies adopted to overcome these constraints. The third section documents the public debate on emigration and the responses to the 'problem.' This is followed in the last section by a prognosis for the future, particularly with regard to the implications for Australia. The article ends with a discussion of the relationship between emigration and nation building, using Singapore as a case study." excerpt

Improving decision speed, accuracy and group cohesion through early information gathering in house-hunting ants.

PubMed

Stroeymeyt, Nathalie; Giurfa, Martin; Franks, Nigel R

2010-09-29

Successful collective decision-making depends on groups of animals being able to make accurate choices while maintaining group cohesion. However, increasing accuracy and/or cohesion usually decreases decision speed and vice-versa. Such trade-offs are widespread in animal decision-making and result in various decision-making strategies that emphasize either speed or accuracy, depending on the context. Speed-accuracy trade-offs have been the object of many theoretical investigations, but these studies did not consider the possible effects of previous experience and/or knowledge of individuals on such trade-offs. In this study, we investigated how previous knowledge of their environment may affect emigration speed, nest choice and colony cohesion in emigrations of the house-hunting ant Temnothorax albipennis, a collective decision-making process subject to a classical speed-accuracy trade-off. Colonies allowed to explore a high quality nest site for one week before they were forced to emigrate found that nest and accepted it faster than emigrating naïve colonies. This resulted in increased speed in single choice emigrations and higher colony cohesion in binary choice emigrations. Additionally, colonies allowed to explore both high and low quality nest sites for one week prior to emigration remained more cohesive, made more accurate decisions and emigrated faster than emigrating naïve colonies. These results show that colonies gather and store information about available nest sites while their nest is still intact, and later retrieve and use this information when they need to emigrate. This improves colony performance. Early gathering of information for later use is therefore an effective strategy allowing T. albipennis colonies to improve simultaneously all aspects of the decision-making process--i.e. speed, accuracy and cohesion--and partly circumvent the speed-accuracy trade-off classically observed during emigrations. These findings should be taken into account in future studies on speed-accuracy trade-offs.

Gulf money in Kerala: coping with the problems of plenty.

PubMed

Kurian, R; Thakore, D

The recent phenomenon of emigration from Kerala to the Gulf countries and the increasing inflow of remittances is having a tremendous impact on Kerala's economy. The state planning board reports that the remittances from the Gulf to this tiny state are Rs. 400 crones/year. An annual inflow of this amount cannot help influence the fortunes of the population. Although emigration from Kerala is not new, the current outflow reached massive proportions only in the wake of the intensive construction boom in the West Asian countries, after a huge volume of petro dollars flowed into those countries in the aftermath of the 1973 hike in oil price. In December 1977 a total of 135,000 Keralities were employed in foreign countries, mainly in West Asia. These adventurous migrants, in their quest for a wage, emigrated mainly from 4 areas in the state: Varkala in Trivandrum district; Thiruvalla in Alleppey district; Chavakkad in Trichur district; and almost all parts of Malappuram district. The bulk of the remittances are sent to households and next of kin concentrated in these areas. This unprecedented inflow of remittances has kindled the hopes of politicians and administrators of tapping these resources to solve the problems of economic development of the state. 1 category of emigrants come from poor households, are poorly educated, and are masons, carpenters, or even unskilled laborers. Because of their ignorance and gullibility they are exploited by middlemen who charge them Rs. 12,000 for a no objection certificate (NOC). Moneylenders are also doing a thriving business. Another type of emigrant is from relatively well off households, better educated, and able to obtain better jobs. There are also rich businessmen and contractors among them. It is this category of better educated emigrant who is able to save a substantial part of his income. State administrative circles note that remittances at best can provide only the financial capital. According to T.C. Razajm a businessman in Abu Dhabi since 1965, emigrants will invest in an industry only if they are convinced of the viability of the project, have a say in its management, and if there is reservation of jobs in the enterprise for their competent dependants. Thus far, the money mobilized into industry seems to be only a tiny proportion of the remittances. A major avenue of investment for the emigrants is real estate and, consequently, the prices of land have registered a marked increase. Even the service sector -- taxis and travel agencies -- have received a sizable boost because of the inflow of Gulf money into the state. According to G. Narayana Pillai, culturally and socially the new found wealth will not bring about any substantial social improvement.

Prey and predator emigration responses in the acarine system Tetranychus urticae-Phytoseiulus persimilis.

PubMed

Bernstein, C

1984-01-01

Some of the processes that influence the emigration of prey and predatory mites from bean plants were investigated experimentally. The emigration of the prey depends on the damage they cause to the plants and on predator density. The predator's emigration rate is a decreasing function of prey density, and does not change (or it slightly decreases) when prey and predator numbers are increased maintaining the same prey/predator ratio. The probability of emigration of the predators is independent of their own density when prey are absent and density dependent when prey density is kep constant. Forty three per cent of the variability in the predator's instantaneous rate of emigration in the different experiments is accounted for by a two parameter negative exponential function of capture rate (number of prey eaten per predator and per unit of time).

Opinions of medical students at the University of Cape Town on emigration, conscription and compulsory community service.

PubMed

Wynchank, D R; Granier, S K

1991-05-04

A study was conducted to determine emigration intentions of medical students at the University of Cape Town. Students from 1st to 5th year complete a self-administered questionnaire. A response rate of 86% was achieved. Over half the students (54%) were considering emigration. The most frequently selected motivating factors were moral dissatisfaction with the present government and career opportunities abroad. Men who were eligible for military conscription rated this factor as an important deterrent to remaining in South Africa, and 81% stated objections to national service. However, 71% would be less likely to emigrate were an alternative national service (ANS) instituted. Should a compulsory community service be implemented, 41% of those eligible would be more inclined to emigrate. Recommendations include the implementation of ANS; a re-evaluation of the compulsory community service proposal; and further investigation of emigration trends and of ways to curb emigration. Suggestions offered are a reappraisal of both selection criteria and medical education; and the provision of incentives for doctors to work in rural areas.

Testing Ødegaard's selective migration hypothesis: a longitudinal cohort study of risk factors for non-affective psychotic disorders among prospective emigrants.

PubMed

van der Ven, E; Dalman, C; Wicks, S; Allebeck, P; Magnusson, C; van Os, J; Selten, J P

2015-03-01

The selection hypothesis posits that the increased rates of psychosis observed among migrants are due to selective migration of people who are predisposed to develop the disorder. To test this hypothesis, we examined whether risk factors for psychosis are more prevalent among future emigrants. A cohort of 49,321 Swedish military conscripts was assessed at age 18 years on cannabis use, IQ, psychiatric diagnosis, social adjustment, history of trauma and urbanicity of place of upbringing. Through data linkage we examined whether these exposures predicted emigration out of Sweden. We also calculated the emigrants' hypothetical relative risk compared with non-emigrants for developing a non-affective psychotic disorder. Low IQ [odds ratio (OR) 0.5, 95% confidence interval (95% CI) 0.3-0.9] and 'poor social adjustment' (OR 0.4, 95% CI 0.2-0.8) were significantly less prevalent among prospective emigrants, whereas a history of urban upbringing (OR 2.3, 95% CI 1.4-3.7) was significantly more common. Apart from a non-significant increase in cannabis use among emigrants (OR 1.6, 95% CI 0.8-3.1), there were no major group differences in any other risk factors. Compared to non-emigrants, hypothetical relative risks for developing non-affective psychotic disorder were 0.7 (95% CI 0.4-1.2) and 0.8 (95% CI 0.7-1.0), respectively, for emigrants narrowly and broadly defined. This study adds to an increasing body of evidence opposing the selection hypothesis.

'Emigration is a matter of self-preservation. The working conditions . . . are killing us slowly': qualitative insights into health professional emigration from Ireland.

PubMed

Humphries, Niamh; McAleese, Sara; Matthews, Anne; Brugha, Ruairi

2015-05-16

Achieving a sustainable health workforce involves training and retaining sufficient staff to deliver health services. The Irish health workforce is characterised by a high level of emigration of Irish-trained staff and a heavy reliance on internationally trained staff. This paper presents qualitative findings from a mixed-method study of doctors, nurses and midwives who have recently emigrated from Ireland. Using Facebook, this study elicited 556 (388 completed) responses to an exploratory mixed-method online survey in July 2014. Respondents provided rich responses to two free-text questions, one on health worker return (N = 343) and another on health professional emigration (N = 209) from the source country (Ireland). Respondents emigrated because of difficult working conditions in the Irish health system (long working hours, uncertain career progression), which compared poorly with conditions in the destination country. Respondents' experiences in the destination country vindicated the decision to emigrate and complicated the decision to return. Their return to Ireland was contingent upon significant reform of the Irish health system and an improvement in working conditions, expressed, for example, as: 'It's not about the money, it's about respect . . . we love working in medicine, but we love our families and health more' (RD283). This paper highlights that doctors, nurses and midwives are emigrating from Ireland in search of better working conditions, clear career progression pathways and a better practice environment. The question for the source country is whether it can retain and attract back emigrant doctors, nurses and midwives by matching their expectations.

Emigration from China in Comparative Perspective*

PubMed Central

Lu, Yao; Liang, Zai; Chunyu, Miao David

2014-01-01

Comparative research on international migration has increasingly focused on immigrant integration rather than the process of emigration. By investigating the different streams of Chinese migration to the United States and Europe, as well as the different stages of Chinese migration to the U.S., this study examines the way in which both receiving and sending contexts combine to shape the process of emigration. Using data from a 2002–2003 survey of emigration from China’s Fujian Province, we demonstrate that under restrictive exit and entry policies and high barriers to migration (i.e., clandestine migration from Fuzhou to the U.S.), resources such as migrant social capital, political capital (cadre resources), and human capital all play a crucial role in the emigration process. However, the roles of these resources in the migration process are limited when migration barriers are sufficiently low and when local governments adopt proactive policies promoting emigration (i.e., legal migration from Mingxi to Europe). Comparisons over time suggest that the importance of migrant social capital, political capital, and human capital has strongly persisted for Fuzhou-US emigration, as a result of tightening exit and entry policies. Despite these marked differences between Fuzhou and Mingxi emigration, the results also point to two general processes that are highly consistent across settings and over time—the cumulative causation of migration and the advantage conferred by traditional positional power (cadre status). PMID:26146414

[Female employment and emigration: from the countries of Africa and Asia to Rome].

PubMed

Arena, G

1983-06-01

Recent trends in female labor migration from third world countries to Rome, Italy, are analyzed. The impact of the demand for various types of labor and of religious background is considered. (summary in ENG, FRE)

Estimation of temporary emigration in male toads

USGS Publications Warehouse

Muths, E.; Scherer, R. D.; Corn, P.S.; Lambert, B.A.

2006-01-01

Male boreal toads (Bufo boreas) are thought to return to the breeding site every year but, if absent in a particular year, will be more likely to return the following year. Using Pollock's robust design we estimated temporary emigration (the probability a male toad is absent from a breeding site in a given year) at three locations in Colorado, USA: two in Rocky Mountain National Park and one in Chaffee County. We present data that suggest that not all male toads return to the breeding site every year. Our analyses indicate that temporary emigration varies by site and time (for example, from 1992 to 1998, the probability of temporary emigration ranged from 10% to 29% and from 3% to 95% at Lost Lake and Kettle Tarn, respectively). Although the results provide weak evidence that males are more likely to return after a year's hiatus, a general pattern of state-dependent temporary emigration was not supported. We also hypothesized relationships between temporary emigration and a number of weather variables. While some competitive models included weather covariates, imprecise and variable estimates of the effects of these covariates precluded fully defining their impact on temporary emigration. ?? 2006 by the Ecological Society of America.

Emigration and welfare in an economy with foreign capital.

PubMed

Djajic, S

1998-08-01

Discussion of the brain drain problem in the 1970s sparked considerable theoretical research upon the effects of emigration. In many cases, it has been determined that emigration reduces the level of welfare of the remaining residents in the source country, regardless of whether or not human capital is exported. In an economy producing traded and non-traded goods. Rivera-Batiz demonstrated that the level of welfare of the remaining residents declines as a consequence of emigration or at most remains unchanged. This paper generalizes the Rivera-Batiz model in another direction to examine the effects of emigration upon the welfare of remaining residents when foreign capital is employed in the economy. In contrast to other earlier studies, it is found that emigration improves the welfare of remaining residents if both they and the migrants have identical preferences and factor endowments. The author also compares the welfare implications of remittance flows back to the source country when they are used to finance consumption and when they are used to finance capital accumulation.

Modeling the macrodynamics of international migration: determinants of emigration from Cyprus, 1946-85.

PubMed

Diamantides, N D; Constantinou, S T

1989-07-01

"A model is presented of international migration that is based on the concept of a pool of potential emigrants at the origin created by push-pull forces and by the establishment of information feedback between origin and destination. The forces can be economic, political, or both, and are analytically expressed by the 'mediating factor'. The model is macrodynamic in nature and provides both for the main secular component of the migratory flow and for transient components caused by extraordinary events. The model is expressed in a Bernoulli-type differential equation through which quantitative weights can be derived for each of the operating causes. Out-migration from the Republic of Cyprus is used to test the tenets of the model." excerpt

Life history of the striped newt at a north-central Florida breeding pond

USGS Publications Warehouse

Johnson, S.A.

2002-01-01

I studied the life history of Striped Newts (Notophthalmus perstriatus) at a breeding pond in north-central Florida. Newts were captured in pitfall traps at a drift-fence as they migrated into and out of the pond basin. During the 2-year study, I recorded 10,290 captures (8,127 individuals) of newts at the drift-fence. Newts were active during each month of the study, but there were four peak activity periods, each of which included immigration and emigration events. Immigration events were almost exclusively comprised of adults, whereas emigration events were comprised of adults and recently transformed larvae. I documented 5,296 recently transformed, immature larvae (efts) and 435 recently transformed mature larvae (paedomorphs) during four distinct periods of emigration. Efts matured in the uplands before returning to the pond to breed. In the uplands, male efts (n = 16) grew 0.0183 mm/day on average, whereas average female (n = 24) growth was 0.0167 mm/day. Immigrating adults of both sexes were significantly smaller than emigrating adults. Emigrating efts were smallest, followed by emigrating paedomorphs, immigrating adults, then emigrating adults. The overall adult sex ratio was 1:1.25 (m:f). Sex ratio of emigrating paedomorphs was highly skewed towards females, with one male for every 4.43 females. Newts tended to move during wetter periods, and captures were significantly correlated with rainfall, but rainfall was a poor predictor of the magnitude of newt movements.

Age-specific survival of tundra swans on the lower Alaska Peninsula

USGS Publications Warehouse

Meixell, Brandt W.; Lindberg, Mark S.; Conn, Paul B.; Dau, Christian P.; Sarvis, John E.; Sowl, Kristine M.

2013-01-01

The population of Tundra Swans (Cygnus columbianus columbianus) breeding on the lower Alaska Peninsula represents the southern extremity of the species' range and is uniquely nonmigratory. We used data on recaptures, resightings, and recoveries of neck-collared Tundra Swans on the lower Alaska Peninsula to estimate collar loss, annual apparent survival, and other demographic parameters for the years 1978–1989. Annual collar loss was greater for adult males fitted with either the thinner collar type (0.34) or the thicker collar type (0.15) than for other age/sex classes (thinner: 0.10, thicker: 0.04). The apparent mean probability of survival of adults (0.61) was higher than that of immatures (0.41) and for both age classes varied considerably by year (adult range: 0.44–0.95, immature range: 0.25–0.90). To assess effects of permanent emigration by age and breeding class, we analyzed post hoc the encounter histories of swans known to breed in our study area. The apparent mean survival of known breeders (0.65) was generally higher than that of the entire marked sample but still varied considerably by year (range 0.26–1.00) and indicated that permanent emigration of breeding swans was likely. We suggest that reductions in apparent survival probability were influenced primarily by high and variable rates of permanent emigration and that immigration by swans from elsewhere may be important in sustaining a breeding population at and near Izembek National Wildlife Refuge.

Applying Organizational Commitment and Human Capital Theories to Emigration Research

ERIC Educational Resources Information Center

Verkhohlyad, Olga; McLean, Gary N.

2012-01-01

Purpose: This study aims to bring some additional insight into the issue of emigration by establishing a relationship between emigration and psychic return of citizens to their human capital investment in the country. Design/methodology/approach: The article adopts a quantitative research strategy. It applies organizational commitment and human…

Space, authority and the female emigrant afloat.

PubMed

Gothard, J

1999-01-01

In the latter half of the nineteenth century, all emigrants travelling out to the Australian colonies experienced a range of measures designed for their protection. As well as physical protection, the future roles of single emigrant women, as paid domestic labour or, ultimately, as unpaid wives and mothers, required that the care accorded to them also took on social and moral concerns. This paper discusses the shipboard structures, particularly spatial arrangements, that were designed both to protect emigrant women in transit to the colonies and to protect the colonial investment.

An emigration versus a globalization perspective of the Lebanese physician workforce: a qualitative study

PubMed Central

2012-01-01

Background Lebanon is witnessing an increased emigration of physicians. The objective of this study was to understand the perceptions of Lebanese policymakers of this emigration, and elicit their proposals for future policies and strategies to deal with this emigration. Methods We conducted semi-structured individual interviews with the deans of Lebanon’s seven medical schools, the presidents of the two physicians professional associations, and governmental officials. We analyzed the results qualitatively. Results Participants differed in the assessment of the extent and gravity of emigration. Lebanon has a surplus of physicians, driven largely by the over-production of graduates by a growing number of medical schools. Participants cited advantages and disadvantages of the emigration on the personal, financial, medical education system, healthcare system, and national levels. Proposed strategies included limiting the number of students entering medical schools, creating job opportunities for graduating students, and implementing quality standards. Most participants acknowledged the globalization of the Lebanese physician workforce, including exchanges with the Gulf region, exchanges with developed countries, and the involvement of North American medical education institutions in the region. Conclusion Many Lebanese policy makers, particularly deans of medical schools, perceive the emigration of the physician workforce as an opportunity in the context of the globalization of the profession. PMID:22646478

An emigration versus a globalization perspective of the Lebanese physician workforce: a qualitative study.

PubMed

Akl, Elie A; Maroun, Nancy; Rahbany, Aline; Hagopian, Amy

2012-05-30

Lebanon is witnessing an increased emigration of physicians. The objective of this study was to understand the perceptions of Lebanese policymakers of this emigration, and elicit their proposals for future policies and strategies to deal with this emigration. We conducted semi-structured individual interviews with the deans of Lebanon's seven medical schools, the presidents of the two physicians professional associations, and governmental officials. We analyzed the results qualitatively. Participants differed in the assessment of the extent and gravity of emigration. Lebanon has a surplus of physicians, driven largely by the over-production of graduates by a growing number of medical schools. Participants cited advantages and disadvantages of the emigration on the personal, financial, medical education system, healthcare system, and national levels. Proposed strategies included limiting the number of students entering medical schools, creating job opportunities for graduating students, and implementing quality standards. Most participants acknowledged the globalization of the Lebanese physician workforce, including exchanges with the Gulf region, exchanges with developed countries, and the involvement of North American medical education institutions in the region. Many Lebanese policy makers, particularly deans of medical schools, perceive the emigration of the physician workforce as an opportunity in the context of the globalization of the profession.

Characterization of Structural and Pigmentary Colors in Common Emigrant (Catopsilia Pomona) Butterfly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghate, Ekata; Kulkarni, G. R.; Bhoraskar, S. V.

2011-10-20

Study of structural colors in case of insects and butterflies is important for their biomimic and biophotonics applications. Structural color is the color which is produced by physical structures and their interaction with light while pigmentary color is produced by absorption of light by pigments. Common Emigrant butterfly is widely distributed in India. It is of moderate size with wing span of about 60-80 mm. The wings are broadly white with yellow or sulphur yellow coloration at places as well as few dark black patches. It belongs to family Pieridae. A study of structural color in case of Common Emigrantmore » butterfly has been carried out in the present work. The characterization of wing color was performed using absorption spectroscopy. Scanning electron microscopic study of the wings of Common Emigrant butterfly showed that three different types of scales are present on the wing surface dorsally. Diffracting structures are present in certain parts of the surfaces of the various scales. Bead like structures are embedded in the intricate structures of the scales. Absorption spectra revealed that a strong absorption peak is seen in the UV-range. Crystalline structure of beads was confirmed by the X-ray diffraction analysis.« less

Fritz Goro on Tape: An Emigre Photojournalist's Professional Biography.

ERIC Educational Resources Information Center

Smith, C. Zoe

Emigres associated with Black Star Picture Agency and "Life" shared much in common: most were well-educated European Jews who became journalists after being involved in other professions and most had worked for German magazines and had emigrated to the United States to pursue their careers while escaping the Nazis. After being trained on…

75 FR 79016 - Notice of Availability of the Final Environmental Impact Statement for the Newmont Mining...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-17

... Newmont Mining Corporation Emigrant Project Plan of Operation, Nevada AGENCY: Bureau of Land Management... Mining Corporation Emigrant Project Plan of Operations and by this notice is announcing its availability...: Copies of the EIS for the Newmont Mining Corporation Emigrant Project Plan of Operation are available for...

Teachers on the Move: International Migration of School Teachers from India

ERIC Educational Resources Information Center

Sharma, Rashmi

2013-01-01

Emigration of qualified teachers from developing countries is a double loss for the source countries, not only leading to emigration of high-skill labour but also affecting their future developmental base when these countries are already struggling to meet the millennium development goals (MDGs) in education. This article discusses emigration of…

Enhanced renewal of regulatory T cells in relation to CD4(+) conventional T lymphocytes in the peripheral compartment.

PubMed

Nogueira, Jeane de Souza; Canto, Fábio Barrozo do; Nunes, Caroline Fraga Cabral Gomes; Vianna, Pedro Henrique Oliveira; Paiva, Luciana de Souza; Nóbrega, Alberto; Bellio, Maria; Fucs, Rita

2016-02-01

CD4(+) Foxp3(+) regulatory T (Treg) cells are necessary for the maintenance of self-tolerance and T-cell homeostasis. This population is kept at stable frequencies in secondary lymphoid organs for the majority of the lifetime, despite permanent thymic emigration or in the face of thymic involution. Continuous competition is expected to occur between recently thymus-emigrated and resident Treg cells (either natural or post-thymically induced). In the present work, we analysed the renewal dynamics of Treg cells compared with CD4(+) Foxp3- conventional T cells (Tconv), using protocols of single or successive T-cell transfers into syngeneic euthymic or lymphopenic (nu/nu or RAG2(-/-)) mice, respectively. Our results show a higher turnover for Treg cells in the peripheral compartment, compared with Tconv cells, when B cell-sufficient euthymic or nude hosts are studied. This increased renewal within the Treg pool, shown by the greater replacement of resident Treg cells by donor counterparts, correlates with augmented rates of proliferation and is not modified following temporary environmental perturbations induced by inflammatory state or microbiota alterations. Notably, the preferential substitution of Treg lymphocytes was not observed in RAG2(-/-) hosts. We showed that limited B-cell replenishment in the RAG2(-/-) hosts decisively contributed to the altered peripheral T-cell homeostasis. Accordingly, weekly transfers of B cells to RAG2(-/-) hosts rescued the preferential substitution of Treg lymphocytes. Our study discloses a new aspect of T-cell homeostasis that depends on the presence of B lymphocytes to regulate the relative incorporation of recently arrived Treg and Tconv cells in the peripheral compartment. © 2015 John Wiley & Sons Ltd.

Development and the Urban and Rural Geography of Mexican Emigration to the United States

ERIC Educational Resources Information Center

Hamilton, Erin R.; Villarreal, Andres

2011-01-01

Past research on international migration from Mexico to the United States uses geographically-limited data and analyzes emigrant-sending communities in isolation. Theories supported by this research may not explain urban emigration, and this research does not consider connections between rural and urban Mexico. In this study we use national data…

Thymic B Cell-Mediated Attack of Thymic Stroma Precedes Type 1 Diabetes Development

PubMed Central

Pinto, Ana Isabel; Smith, Jennifer; Kissack, Miriam R.; Hogg, Karen G.; Green, E. Allison

2018-01-01

Type 1 diabetes (T1D) results from a coordinated autoimmune attack of insulin producing beta cells in the pancreas by the innate and adaptive immune systems, beta cell death being predominantly T cell-mediated. In addition to T cells, peripheral B cells are important in T1D progression. The thymus of mice and man also contains B cells, and lately they have been linked to central tolerance of T cells. The role of thymic B cells in T1D is undefined. Here, we show there are abnormalities in the thymic B cell compartment before beta cell destruction and T1D manifestation. Using non-obese diabetic (NOD) mice, we document that preceding T1D development, there is significant accumulation of thymic B cells-partly through in situ development- and the putative formation of ectopic germinal centers. In addition, in NOD mice we quantify thymic plasma cells and observe in situ binding of immunoglobulins to undefined antigens on a proportion of medullary thymic epithelial cells (mTECs). By contrast, no ectopic germinal centers or pronounced intrathymic autoantibodies are detectable in animals not genetically predisposed to developing T1D. Binding of autoantibodies to thymic stroma correlates with apoptosis of mTECs, including insulin-expressing cells. By contrast, apoptosis of mTECs was decreased by 50% in B cell-deficient NOD mice suggesting intrathymic autoantibodies may selectively target certain mTECs for destruction. Furthermore, we observe that these thymic B cell-associated events correlated with an increased prevalence of premature thymic emigration of T cells. Together, our data suggest that the thymus may be a principal autoimmune target in T1D and contributes to disease progression.

Different forms, reasons and motivations for return migration of persons who voluntarily decide to return to their countries of origin.

PubMed

Callea, S

1986-03-01

Although the 1973 oil crisis did not have the drastic effects on immigration which were originally feared, it did end a period of quasi-liberal immigration policy, establish intense and effective international cooperation on immigration, and arouse great interest in immigration studies and research. This paper analyzes the situations arising as a result of the petroleum shortage and focuses on the conditions relating to the return of emigrants to Southern European countries. This new research draws attention to the following fundamental aspects of the immigration problem: 1) the emigrant's return to his homeland cannot be considered a factor in development; it is a positive element in development only if the right socioeconomic conditions exist in the country of origin. 2) Concern for children's education is one of the most common reasons for return. 3) A large percentage of emigrants are satisfied with their work abroad. 4) An emigrant's return potential is wasted due to the slight use that is made of the resources he offers. 5) Returning workers most often want to set up an independent enterprise. 6) Savings are generally used to buy a house or farm. 7) Vocational level does not increase significantly between emigration and returning, though this increase becomes greater the longer the emigrant stays abroad. 8) The number of returning emigrants is too slight to bring about any change in the country of origin. 9) Incentives and subsidies to encourage return have not had a considerable impact on the decision to return. Callea recommends that officials of the country of origin posted abroad be assigned to counsel returning emigrants on finding employment, attending vocational development courses, obtaining housing, accruing interests and savings, and on the problems and perspectives of sociocultural reintegration.

The emigration of Germany's Jewish dermatologists in the period of National Socialism.

PubMed

Eppinger, S; Meurer, M; Scholz, A

2003-09-01

In the context of our investigation, we found information on 432 (76%) of the 569 Jewish dermatologists in Germany. There is evidence that 57 (10%) of the Jewish dermatologists were murdered in concentration camps, 61 (10.7%) died a natural death, 13 (2%) committed suicide, and 25 (4%) survived the Third Reich in Germany. After 1933, 276 (49%) Jewish dermatologists were able to leave Germany; the United States of America was the main destination and 107 (or 41%) emigrated there. A total of 34 (13%) Jewish dermatologists emigrated from Germany to Palestine and 16 to Latin America. Regarding emigration to other European countries, 20 of the Jewish dermatologists from Germany went to Great Britain (including Walter Freudenthal, 1893-1952, and Ernst Sklarz, 1894-1975), and 24 emigrated to other European countries, such as France (Rudolf Mayer, 1895-1962), Sweden (Carl Lennhoff, 1883-1963), and the Netherlands (Otto Schlein, 1895-1944).

Patterns of Spanish Emigration to the New World (1493-1580). Special Studies No. 34.

ERIC Educational Resources Information Center

Boyd-Bowman, Peter

The four periods discussed in this publication cover the patterns of Spanish emigration to the New World, mainly on the regional level and in terms of percentages. The effects of this emigration on the various Spanish American dialects are discussed. In the initial period (1493-1519), the largest single group, in every year and on all major…

Neutrophil Recruitment by Tumor Necrosis Factor from Mast Cells in Immune Complex Peritonitis

NASA Astrophysics Data System (ADS)

Zhang, Yan; Ramos, Bernard F.; Jakschik, Barbara A.

1992-12-01

During generalized immune complex-induced inflammation of the peritoneal cavity, two peaks of tumor necrosis factor (TNF) were observed in the peritoneal exudate of normal mice. In mast cell-deficient mice, the first peak was undetected, and the second peak of TNF and neutrophil influx were significantly reduced. Antibody to TNF significantly inhibited neutrophil infiltration in normal but not in mast cell-deficient mice. Mast cell repletion of the latter normalized TNF, neutrophil mobilization, and the effect of the antibody to TNF. Thus, in vivo, mast cells produce the TNF that augments neutrophil emigration.

Does the Attitude Toward Organ Donation Change as a Function of the Country Where People Emigrate? Study Between Uruguayan Emigrants to the United States and Spain.

PubMed

Ríos, A; López-Navas, A I; Sánchez, Á; Ayala, M A; Garrido, G; Sebastián, M J; Martinez-Alarcón, L; Ramis, G; Hernández, A M; Ramírez, P; Parrilla, P

2018-03-01

The Uruguayan population is sensitized toward transplantation. However, it has not been studied how this awareness can change when emigrating to different countries. To analyze the attitude toward cadaveric organ donation and living organ donation between the Uruguayan population residing in Florida (United States) and the Uruguayan population residing in Spain. Adults born in Uruguay and residing in Florida and Spain were screened. The questionnaire "PCID-DTO Ríos" (donation of cadaveric organs) and "PCID-DVR Ríos" (living renal donation) were used. Subjects were randomly selected according to age and gender stratification. Support from Latin-American immigration associations in Spain and Florida was needed. The survey was anonymized and self-administered. Verbal consent was obtained to collaborate in the study. Because the emigrant population to Spain is far larger than the emigrant population to the United States, a 2:1 proportional sampling was performed (n = 132). Sixty-seven percent of residents in Spain were in favor of organ donation at the time of death compared with 50% among residents in Florida (P = .082), and 100% of residents in Spain were in favor of living renal donation compared with 50% of those living in Florida (P < .001). The attitude toward donation is more favorable among Uruguayan emigrants to Spain than emigrants to the United States, especially in related kidney donation. Copyright © 2017 Elsevier Inc. All rights reserved.

Emigration-related attitudes of the final year medical students in Croatia: a cross-sectional study at the dawn of the EU accession

PubMed Central

Kolčić, Ivana; Čikeš, Mihaela; Boban, Kristina; Bućan, Jasna; Likić, Robert; Ćurić, Goran; Đogaš, Zoran; Polašek, Ozren

2014-01-01

Aim To investigate the emigration-related attitudes of final year medical students in Croatia at the dawn of the EU accession in 2013. Methods All final-year medical students at four Croatian medical schools (Zagreb, Rijeka, Split, and Osijek) were invited to participate in a cross-sectional survey on emigration attitudes. Results Among 260 respondents (response rate 61%), 90 students (35%) reported readiness for permanent emigration, expecting better quality of life (N = 22, 31%), better health care organization (N = 17, 24%), more professional challenges (N = 10, 14%), or simply to get a job (N = 8, 11%), while the least common expectation were greater earnings (N = 7, 10%). The most common target countries were Germany (N = 36, 40%), USA and Canada (N = 15, 17%), and UK (N = 10, 11%). In a multivariate analysis, readiness for permanent emigration was associated with an interest in undertaking a temporary training abroad (odds ratio [OR] 6.87; 95% confidence interval [CI] 2.83-16.72), while the belief that the preferred specialty could be obtained in Croatia appeared protective against emigration (OR 0.26; 95% CI 0.12-0.59). Conclusion Despite shortages of health care workers in Croatia, the percentage of students with emigration propensity was rather high. Prevalent negative perception of the Croatian health care and recent Croatian accession to the EU pose a threat of losing newly graduated physicians to EU countries. PMID:25358878

Candidate Microbicides Block HIV-1 Infection of Human Immature Langerhans Cells within Epithelial Tissue Explants

PubMed Central

Kawamura, Tatsuyoshi; Cohen, Sandra S.; Borris, Debra L.; Aquilino, Elisabeth A.; Glushakova, Svetlana; Margolis, Leonid B.; Orenstein, Jan M.; Offord, Robin E.; Neurath, A. Robert; Blauvelt, Andrew

2000-01-01

Initial biologic events that underlie sexual transmission of HIV-1 are poorly understood. To model these events, we exposed human immature Langerhans cells (LCs) within epithelial tissue explants to two primary and two laboratory-adapted HIV-1 isolates. We detected HIV-1Ba-L infection in single LCs that spontaneously emigrated from explants by flow cytometry (median of infected LCs = 0.52%, range = 0.08–4.77%). HIV-1–infected LCs downregulated surface CD4 and CD83, whereas MHC class II, CD80, and CD86 were unchanged. For all HIV-1 strains tested, emigrated LCs were critical in establishing high levels of infection (0.1–1 μg HIV-1 p24 per milliliter) in cocultured autologous or allogeneic T cells. HIV-1Ba-L (an R5 HIV-1 strain) more efficiently infected LC–T cell cocultures when compared with HIV-1IIIB (an X4 HIV-1 strain). Interestingly, pretreatment of explants with either aminooxypentane-RANTES (regulated upon activation, normal T cell expressed and secreted) or cellulose acetate phthalate (potential microbicides) blocked HIV-1 infection of LCs and subsequent T cell infection in a dose-dependent manner. In summary, we document HIV-1 infection in single LCs after exposure to virus within epithelial tissue, demonstrate that relatively low numbers of these cells are capable of inducing high levels of infection in cocultured T cells, and provide a useful explant model for testing of agents designed to block sexual transmission of HIV-1. PMID:11085750

Scandinavian Emigration to Australia and New Zealand Project. Proceedings of a Symposium (Turku, Finland, February 17-19, 1982). Migration Studies C7.

ERIC Educational Resources Information Center

Koivukangas, Olavi, Ed.

These proceedings of a 1982 symposium on Scandinavian emigration in Australia include presentations on three general topics: field work conducted in Australia and New Zealand in 1980-82; research progress; and Australian immigration policy. The presentors and their papers are: (1) Hans Norman, "The Emigration to America from the Nordic…

Physician emigration from sub-Saharan Africa to the United States: analysis of the 2011 AMA physician masterfile.

PubMed

Tankwanchi, Akhenaten Benjamin Siankam; Ozden, Cağlar; Vermund, Sten H

2013-01-01

The large-scale emigration of physicians from sub-Saharan Africa (SSA) to high-income nations is a serious development concern. Our objective was to determine current emigration trends of SSA physicians found in the physician workforce of the United States. We analyzed physician data from the World Health Organization (WHO) Global Health Workforce Statistics along with graduation and residency data from the 2011 American Medical Association Physician Masterfile (AMA-PM) on physicians trained or born in SSA countries who currently practice in the US. We estimated emigration proportions, year of US entry, years of practice before emigration, and length of time in the US. According to the 2011 AMA-PM, 10,819 physicians were born or trained in 28 SSA countries. Sixty-eight percent (n = 7,370) were SSA-trained, 20% (n = 2,126) were US-trained, and 12% (n = 1,323) were trained outside both SSA and the US. We estimated active physicians (age ≤ 70 years) to represent 96% (n = 10,377) of the total. Migration trends among SSA-trained physicians increased from 2002 to 2011 for all but one principal source country; the exception was South Africa whose physician migration to the US decreased by 8% (-156). The increase in last-decade migration was >50% in Nigeria (+1,113) and Ghana (+243), >100% in Ethiopia (+274), and >200% (+244) in Sudan. Liberia was the most affected by migration to the US with 77% (n = 175) of its estimated physicians in the 2011 AMA-PM. On average, SSA-trained physicians have been in the US for 18 years. They practiced for 6.5 years before US entry, and nearly half emigrated during the implementation years (1984-1999) of the structural adjustment programs. Physician emigration from SSA to the US is increasing for most SSA source countries. Unless far-reaching policies are implemented by the US and SSA countries, the current emigration trends will persist, and the US will remain a leading destination for SSA physicians emigrating from the continent of greatest need. Please see later in the article for the Editors' Summary.

Physician Emigration from Sub-Saharan Africa to the United States: Analysis of the 2011 AMA Physician Masterfile

PubMed Central

Tankwanchi, Akhenaten Benjamin Siankam; Özden, Çağlar; Vermund, Sten H.

2013-01-01

Background The large-scale emigration of physicians from sub-Saharan Africa (SSA) to high-income nations is a serious development concern. Our objective was to determine current emigration trends of SSA physicians found in the physician workforce of the United States. Methods and Findings We analyzed physician data from the World Health Organization (WHO) Global Health Workforce Statistics along with graduation and residency data from the 2011 American Medical Association Physician Masterfile (AMA-PM) on physicians trained or born in SSA countries who currently practice in the US. We estimated emigration proportions, year of US entry, years of practice before emigration, and length of time in the US. According to the 2011 AMA-PM, 10,819 physicians were born or trained in 28 SSA countries. Sixty-eight percent (n = 7,370) were SSA-trained, 20% (n = 2,126) were US-trained, and 12% (n = 1,323) were trained outside both SSA and the US. We estimated active physicians (age ≤70 years) to represent 96% (n = 10,377) of the total. Migration trends among SSA-trained physicians increased from 2002 to 2011 for all but one principal source country; the exception was South Africa whose physician migration to the US decreased by 8% (−156). The increase in last-decade migration was >50% in Nigeria (+1,113) and Ghana (+243), >100% in Ethiopia (+274), and >200% (+244) in Sudan. Liberia was the most affected by migration to the US with 77% (n = 175) of its estimated physicians in the 2011 AMA-PM. On average, SSA-trained physicians have been in the US for 18 years. They practiced for 6.5 years before US entry, and nearly half emigrated during the implementation years (1984–1999) of the structural adjustment programs. Conclusion Physician emigration from SSA to the US is increasing for most SSA source countries. Unless far-reaching policies are implemented by the US and SSA countries, the current emigration trends will persist, and the US will remain a leading destination for SSA physicians emigrating from the continent of greatest need. Please see later in the article for the Editors' Summary PMID:24068894

Blood lead level analysis among refugee children resettled in New Hampshire and Rhode Island.

PubMed

Raymond, Jaime S; Kennedy, Chinaro; Brown, Mary Jean

2013-01-01

To examine the association between refugee status and elevated blood lead levels (EBLLs) among children living in two U.S. cities and to assess the effect of the Centers for Disease Control and Prevention recommendations for BLL testing of newly emigrated refugee children for EBLLs. A longitudinal study was conducted of 1,007 refugee children and 953 nonrefugee children living, when blood testing occurred, in the same buildings in Manchester, New Hampshire and Providence, Rhode Island. Surveillance and blood lead data were collected from both sites, including demographic information, BLLs, sample type, refugee status, and age of housing. Refugee children living in Manchester were statistically significantly more likely to have an EBLL compared with nonrefugee children even after controlling for potential confounders. We did not find this association in Providence. Compared with before enactment, the mean time of refugee children to fall below 10 μg/dL was significantly shorter after the recommendations to test newly emigrated children were enacted. Refugee children living in Manchester were significantly more likely to have an EBLL compared with nonrefugee children. And among refugee children, we found a statistically significant difference in the mean days to BLL decline <10 μg/dL before and after recommendations to test newly emigrated children. © 2012 Wiley Periodicals, Inc.

The ability of individuals to assess population density influences the evolution of emigration propensity and dispersal distance.

PubMed

Poethke, Hans Joachim; Gros, Andreas; Hovestadt, Thomas

2011-08-07

We analyze the simultaneous evolution of emigration and settlement decisions for actively dispersing species differing in their ability to assess population density. Using an individual-based model we simulate dispersal as a multi-step (patch to patch) movement in a world consisting of habitat patches surrounded by a hostile matrix. Each such step is associated with the same mortality risk. Our simulations show that individuals following an informed strategy, where emigration (and settlement) probability depends on local population density, evolve a lower (natal) emigration propensity but disperse over significantly larger distances - i.e. postpone settlement longer - than individuals performing density-independent emigration. This holds especially when variation in environmental conditions is spatially correlated. Both effects can be traced to the informed individuals' ability to better exploit existing heterogeneity in reproductive chances. Yet, already moderate distance-dependent dispersal costs prevent the evolution of multi-step (long-distance) dispersal, irrespective of the dispersal strategy. Copyright © 2011 Elsevier Ltd. All rights reserved.

Signal integration and cross-talk during thymocyte migration and emigration

PubMed Central

Love, Paul E.; Bhandoola, Avinash

2013-01-01

The thymus produces self-tolerant functionally competent T cells. This occurs by the import of multipotent hematopoietic progenitors that are signalled to adopt the T cell fate. Expression of T cell specific genes, including those encoding the T cell receptor (TCR), is followed by positive and negative selection and the eventual export of mature T cells. Significant progress has been made in elucidating the signals that direct progenitor cell trafficking to, within and out of the thymus. These advances are the subject of this Review, with a particular focus on the role of reciprocal cooperative and regulatory interactions between TCR and chemokine receptor-mediated signalling. PMID:21701522

[Emigration and immigration in Italy. (1861-2011)].

PubMed

Pasini, Walter

2011-01-01

The creation of the Italian Kingdom was characterized by the mass emigration of Italian people, mainly peasants towards European and American destinations. Poverty, unemployment, diseases, like pellagra, malaria and tubercolosis forced millions of Italians to leave the Country. The phenomenon of emigration is usually divided in three periods: the mass emigration from 1976 to 1914, the second one between the two world wars, the third one from 1946 to 1976. In the last quarter of the 20th century the number of repatriations overcome expatriations and the number of immigrants from Albania, Romania, Senegal, Tunisia, China, Philippines grew up becoming more and more important. Italy was a country of emigrants, now is a country of immigrants. It is difficult to compare the work conditions of the Italian emigrants with the new immigrants. At the end of the 19th Century or in the first decades of the 20th Century there were no consideration for human rights, no legislations to protect workers. Immigration from North Africa and from all the low and middle income countries should be studied in all its aspects because it will characterize our future. In the new era of economical globalization, Universities should prepare the new medical doctors to extend their professional culture to a international dimension to be able to cope with the new challenges of our time.

Private sector contributions and their effect on physician emigration in the developing world

PubMed Central

Ugarte-Gil, Cesar; Darko, Kwame

2013-01-01

Abstract The contribution made by the private sector to health care in a low- or middle-income country may affect levels of physician emigration from that country. The increasing importance of the private sector in health care in the developing world has resulted in newfound academic interest in that sector’s influences on many aspects of national health systems. The growth in physician emigration from the developing world has led to several attempts to identify both the factors that cause physicians to emigrate and the effects of physician emigration on primary care and population health in the countries that the physicians leave. When the relevant data on the emerging economies of Ghana, India and Peru were investigated, it appeared that the proportion of physicians participating in private health-care delivery, the percentage of health-care costs financed publicly and the amount of private health-care financing per capita were each inversely related to the level of physician expatriation. It therefore appears that private health-care delivery and financing may decrease physician emigration. There is clearly a need for similar research in other low- and middle-income countries, and for studies to see if, at the country level, temporal trends in the contribution made to health care by the private sector can be related to the corresponding trends in physician emigration. The ways in which private health care may be associated with access problems for the poor and therefore reduced equity also merit further investigation. The results should be of interest to policy-makers who aim to improve health systems worldwide. PMID:23476095

Private sector contributions and their effect on physician emigration in the developing world.

PubMed

Loh, Lawrence C; Ugarte-Gil, Cesar; Darko, Kwame

2013-03-01

The contribution made by the private sector to health care in a low- or middle-income country may affect levels of physician emigration from that country. The increasing importance of the private sector in health care in the developing world has resulted in newfound academic interest in that sector's influences on many aspects of national health systems. The growth in physician emigration from the developing world has led to several attempts to identify both the factors that cause physicians to emigrate and the effects of physician emigration on primary care and population health in the countries that the physicians leave. When the relevant data on the emerging economies of Ghana, India and Peru were investigated, it appeared that the proportion of physicians participating in private health-care delivery, the percentage of health-care costs financed publicly and the amount of private health-care financing per capita were each inversely related to the level of physician expatriation. It therefore appears that private health-care delivery and financing may decrease physician emigration. There is clearly a need for similar research in other low- and middle-income countries, and for studies to see if, at the country level, temporal trends in the contribution made to health care by the private sector can be related to the corresponding trends in physician emigration. The ways in which private health care may be associated with access problems for the poor and therefore reduced equity also merit further investigation. The results should be of interest to policy-makers who aim to improve health systems worldwide.

Biphasic influence of Miz1 on neural crest development by regulating cell survival and apical adhesion complex formation in the developing neural tube

PubMed Central

Kerosuo, Laura; Bronner, Marianne E.

2014-01-01

Myc interacting zinc finger protein-1 (Miz1) is a transcription factor known to regulate cell cycle– and cell adhesion–related genes in cancer. Here we show that Miz1 also plays a critical role in neural crest development. In the chick, Miz1 is expressed throughout the neural plate and closing neural tube. Its morpholino-mediated knockdown affects neural crest precursor survival, leading to reduction of neural plate border and neural crest specifier genes Msx-1, Pax7, FoxD3, and Sox10. Of interest, Miz1 loss also causes marked reduction of adhesion molecules (N-cadherin, cadherin6B, and α1-catenin) with a concomitant increase of E-cadherin in the neural folds, likely leading to delayed and decreased neural crest emigration. Conversely, Miz1 overexpression results in up-regulation of cadherin6B and FoxD3 expression in the neural folds/neural tube, leading to premature neural crest emigration and increased number of migratory crest cells. Although Miz1 loss effects cell survival and proliferation throughout the neural plate, the neural progenitor marker Sox2 was unaffected, suggesting a neural crest–selective effect. The results suggest that Miz1 is important not only for survival of neural crest precursors, but also for maintenance of integrity of the neural folds and tube, via correct formation of the apical adhesion complex therein. PMID:24307680

IL-9-producing cells in the development of IgE-mediated food allergy.

PubMed

Shik, Dana; Tomar, Sunil; Lee, Jee-Boong; Chen, Chun-Yu; Smith, Andrew; Wang, Yui-Hsi

2017-01-01

Food allergy is a harmful immune reaction driven by uncontrolled type 2 immune responses. Considerable evidence demonstrates the key roles of mast cells, IgE, and TH2 cytokines in mediating food allergy. However, this evidence provides limited insight into why only some, rather than all, food allergic individuals are prone to develop life-threatening anaphylaxis. Clinical observations suggest that patients sensitized to food through the skin early in life may later develop severe food allergies. Aberrant epidermal thymic stromal lymphopoietin and interleukin (IL) 33 production and genetic predisposition can initiate an allergic immune response mediated by dendritic cells and CD4 + TH2 cells in inflamed skin. After allergic sensitization, intestinal IL-25 and food ingestion enhance concerted interactions between type 2 innate lymphoid cells (ILC2s) and CD4 + TH2 cells, which perpetuate allergic reactions from the skin to the gut. IL-4 and cross-linking of antigen/IgE/FcεR complexes induce emigrated mast cell progenitors to develop into the multi-functional IL-9-producing mucosal mast cells, which produce prodigious amounts of IL-9 and mast cell mediators to drive intestinal mastocytosis in an autocrine loop. ILC2s and TH9 cells may also serve as alternative cellular sources of IL-9 to augment the amplification of intestinal mastocytosis, which is the key cellular checkpoint in developing systemic anaphylaxis. These findings provide a plausible view of how food allergy develops and progresses in a stepwise manner and that atopic signals, dietary allergen ingestion, and inflammatory cues are fundamental in promoting life-threatening anaphylaxis. This information will aid in improving diagnosis and developing more effective therapies for food allergy-triggered anaphylaxis.

IL-9–producing cells in the development of IgE-mediated food allergy

PubMed Central

Shik, Dana; Tomar, Sunil; Lee, Jee-Boong; Chen, Chun-Yu; Smith, Andrew; Wang, Yui-Hsi

2016-01-01

Food allergy is a harmful immune reaction driven by uncontrolled type-2 immune responses. Considerable evidence demonstrates the key roles of mast cells, IgE, and TH2 cytokines in mediating food allergy. However, this evidence provides limited insight into why only some, rather than all, food allergic individuals are prone to develop life-threatening anaphylaxis. Clinical observations suggest that patients sensitized to food through the skin early in life may later develop severe food allergies. Aberrant epidermal thymic stromal lymphopoietin and interleukin (IL) 33 production and genetic predisposition can initiate an allergic immune response mediated by dendritic cells and CD4+TH2 cells in inflamed skin. After allergic sensitization, intestinal IL-25 and food ingestion enhance concerted interactions between type-2 innate lymphoid cells (ILC2s) and CD4+TH2 cells, which perpetuate allergic reactions from skin to the gut. IL-4 and crosslinking of antigen/IgE/FcεR complexes induce emigrated mast cell progenitors to develop into the multi-functional IL-9–producing mucosal mast cells, which produce prodigious amounts of IL-9 and mast cell mediators to drive intestinal mastocytosis in an autocrine loop. ILC2s and TH9 cells may also serve as alternative cellular sources of IL-9 to augment the amplification of intestinal mastocytosis, which is the key cellular checkpoint in developing systemic anaphylaxis. These findings provide a plausible view of how food allergy develops and progresses in a stepwise manner and that atopic signals, dietary allergen ingestion, and inflammatory cues are fundamental in promoting life-threatening anaphylaxis. This information will aid in improving diagnosis and developing more effective therapies for food allergy–triggered anaphylaxis. PMID:27909880

Post-thymic maturation: young T cells assert their individuality.

PubMed

Fink, Pamela J; Hendricks, Deborah W

2011-07-22

T cell maturation was once thought to occur entirely within the thymus. Now, evidence is mounting that the youngest peripheral T cells in both mice and humans comprise a distinct population from their more mature, yet still naive, counterparts. These cells, termed recent thymic emigrants (RTEs), undergo a process of post-thymic maturation that can be monitored at the levels of cell phenotype and immune function. Understanding this final maturation step in the process of generating useful and safe T cells is of clinical relevance, given that RTEs are over-represented in neonates and in adults recovering from lymphopenia. Post-thymic maturation may function to ensure T cell fitness and self tolerance.

Emigration of Natural and Hatchery Chinook Salmon and Steelhead Smolts from the Imnaha River, Oregon, 1998-1999 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cleary, Peter J.; Blenden, Michael L.; Kucera, Paul A.

2002-08-01

This report summarizes the results of the Lower Snake River Compensation Plan Hatchery Evaluation Studies (LSRCP) and the Imnaha Smolt Monitoring Program (SMP) for the 1999 smolt migration from the Imnaha River, Oregon. These studies were designed and closely coordinated to provide information about juvenile natural and hatchery chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss) biological characteristics, behavior and emigrant timing, survival, arrival timing and travel time to the Snake River dams and McNary Dam on the Columbia River. Data collected from these studies are shared with the Fish Passage Center (FPC). These data are essential to quantify smoltmore » survival rates under the current passage conditions and to evaluate the future recovery strategies that seek to optimize smolt survival through the hydroelectric system. Information shared with the FPC assists with in-season shaping of flow and spill management requests in the Snake River reservoirs. The Bonneville Power Administration and the United States Fish and Wildlife Service contracted the Nez Perce Tribe (NPT) to monitor emigration timing and tag 21,200 emigrating natural and hatchery chinook salmon and steelhead smolts from the Imnaha River during the spring emigration period (March 1-June 15) with passive integrated transponder (PIT) tags. The completion of trapping in the spring of 1999 marked the eighth year of emigration studies on the Imnaha River and the sixth year of participating in the FPC smolt monitoring program. Monitoring and evaluation objectives were to: (1) Determine spring emigration timing of chinook salmon and steelhead smolts collected at the Imnaha River trap. (2) Evaluate effects of flow, temperature and other environmental factors on emigration timing. (3) Monitor the daily catch and biological characteristics of juvenile chinook salmon and steelhead smolts collected at the Imnaha River screw trap. (4) Determine emigration timing, travel time, and in-river survival of PIT tagged hatchery chinook salmon smolts released at the Imnaha River acclimation facility to the Imnaha River Trap. (5) Determine arrival timing, travel time and estimated survival of PIT tagged hatchery and natural chinook salmon and natural and hatchery steelhead smolts from the Imnaha River to Snake and Columbia river dams.« less

Emigration dynamics in South Asia, IOM / UNFPA workshop, 2-3 September 1996, IOM headquarters, Geneva, Switzerland.

PubMed

Appleyard, R

1996-01-01

This paper describes the six research monographs that were presented at the Emigration Dynamic Workshops in South Asia in September 1996. Research reports were presented by Associate Professor Nasra Shah on an overview of emigration dynamics, Dr. Godfrey Gunatilleke on the role of networks and community structures in migration from Sri Lanka, Dr. Raisul Awal Mahmood on illegal migration from Bangladesh to Singapore, Kuala Lumpur, Bangkok, and Delhi due to desperate poverty, Dr. Farooq-i-Azam on high and low labor-sending migration districts in Pakistan, Dr. Mahendra K. Premi on the impact of internal Indian migration on international migration, and Dr. P.R. Gopinathan Nair on emigration from Kerala, India, to the Middle East. Representatives of South Asian governments discussed the implications of the research findings. Pakistan's representative urged cooperation and joint strategies among labor-sending countries. He cautioned that income and remittance estimates were unstable and unrealistic for inclusion in economic development plans. The Indian representative noted that, although Indian emigration is low, it is highly visible in the press. He agreed with the suggestion for greater cooperation between sending countries. The Bangladesh representative stated that the country needed to locate new markets for Bangladeshi emigrants, to guarantee the rights of emigrant workers, and to prevent trafficking in illegal migrant workers. Three major topics were discussed in the workshop session on the implementation of programs based on research findings. Workshop participants recommended updated information on migration trends, updated information on labor markets in receiving countries, formal and regular policy dialogue between sending countries, and promotion of continuing research by the International Organization on Migration.

The macrodynamics of international migration as a sociocultural diffusion process. Part A: theory.

PubMed

Diamantides, N D

1992-11-01

"This study formulates a model of the macrodynamics of international migration using a differential equation to capture the push-pull forces that propel it. The model's architecture rests on the functioning of information feedback between settled friends and family at the destination and potential emigrants at the origin." The author tests the model using data on Greek emigration to the United States since 1820 and on total emigration from Cyprus since 1946. excerpt

Eight color immunophenotyping of T-, B- and NK-cell subpopulations for characterization of chronic immunodeficiencies.

PubMed

A, Boldt; S, Borte; S, Fricke; K, Kentouche; F, Emmrich; M, Borte; F, Kahlenberg; U, Sack

2014-01-16

Background: The heterogeneity of primary and secondary immunodeficiencies demands for the development of a comprehensive flow cytometric screening system, based on reference values that support a standardized immunophenotypic characterization of most lymphocyte subpopulations. Methods: Peripheral blood samples from healthy adult volunteers (n=25) were collected and split into eight panel fractions (100µl each). Subsequently, pre-mixed 8-color antibody cocktails were incubated per specific panel of whole blood to detect and differentiate cell subsets of: (i) a general lymphocyte overviews, (ii) B-cell subpopulations, (iii) CD4+ subpopulations, (iv) CD8+ subpopulations, (v) regulatory T-cells, (vi) recent thymic emigrants, (vii) NK-cell subpopulations, (viii) NK-cell activation markers. All samples were lysed, washed and measured by flow cytometry. FACS DIVA software was used for data analysis and calculation of quadrant statistics (mean values, standard error of mean, percentile ranges). Results: Whole blood staining of lymphocytes provided the analysis of: (i) CD3+, 4+, 8+, 19+, 16/56+, and activated CD4/8 cells; (ii) immature, naïve, non-switched/switched, memory, (activated) CD21 low , transitional B-cells, plasmablasts/plasmacells; (iii and iv) naïve, central memory, effector, effector memory, TH1/TH2/TH17-like and CCR5+CD8-cells; (v) CD25+, regulatory T-cells (naïve/memory, HLA-DR+); (vi) α/β- and γ/δ-T-cells, recent thymic emigrants in CD4/CD8 cells; (vii) immature/mature CD56 bright , CD94/NKG2D+ NK-cells; and (viii) Nkp30, 44, 46 and CD57+NK-cells. Clinical examples and quadrant statistics are provided. Conclusion: The present study represents a practical approach to standardize the immunophenotyping of most T-, B- and NK-cell subpopulations. That allows differentiating, whether abnormalities or developmental shifts observed in lymphocyte subpopulations originates either from primary or secondary immunological disturbance. © 2014 Clinical Cytometry Society. Copyright © 2014 Clinical Cytometry Society.

Immune reconstitution in patients with Fanconi anemia after allogeneic bone marrow transplantation.

PubMed

Perlingeiro Beltrame, Miriam; Malvezzi, Mariester; Bonfim, Carmem; Covas, Dimas Tadeu; Orfao, Alberto; Pasquini, Ricardo

2014-07-01

Fanconi anemia is an autosomal recessive or X-linked genetic disorder characterized by bone marrow (BM) failure/aplasia. Failure of hematopoiesis results in depletion of the BM stem cell reservoir, which leads to severe anemia, neutropenia and thrombocytopenia, frequently requiring therapeutic interventions, including hematopoietic stem cell transplantation (HSCT). Successful BM transplantation (BMT) requires reconstitution of normal immunity. In the present study, we performed a detailed analysis of the distribution of peripheral blood subsets of T, B and natural killer (NK) lymphocytes in 23 patients with Fanconi anemia before and after BMT on days +30, +60, +100, +180, +270 and +360. In parallel, we evaluated the effect of related versus unrelated donor marrow as well as the presence of graft-versus-host disease (GVHD). After transplantation, we found different kinetics of recovery for the distinct major subsets of lymphocytes. NK cells were the first to recover, followed by cytotoxic CD8(+) T cells and B cells, and finally CD4(+) helper T cells. Early lymphocyte recovery was at the expense of memory cells, potentially derived from the graft, whereas recent thymic emigrant (CD31(+) CD45RA(+)) and naive CD4(+) or CD8(+) T cells rose only at 6 months after HSCT, in the presence of immunosuppressive GVHD prophylactic agents. Only slight differences were observed in the early recovery of cytotoxic CD8(+) T cells among those cases receiving a graft from a related donor versus an unrelated donor. Patients with GVHD displayed a markedly delayed recovery of NK cells and B cells as well as of regulatory T cells and both early thymic emigrant and total CD4(+) T cells. Our results support the utility of post-transplant monitoring of a peripheral blood lymphocyte subset for improved follow-up of patients with Fanconi anemia undergoing BMT. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Emigration dynamics from and within South Asia.

PubMed

Shah, N M

1995-01-01

This review of current knowledge about emigration dynamics from and within South Asia (Bangladesh, India, Pakistan, and Sri Lanka) opens with a brief history of the three phases of emigration from the area since the 1830s (plantation labor; postindependence to the UK, US, Canada, and Australia; and labor migration to the oil-exporting countries). The influence of the creation of Pakistan and Bangladesh is also covered as are British colonial and commonwealth policies. It is noted that migration data are incomplete and that India exhibits an ambivalence about collecting such information. The discussion then turns to emigration since 1970 and considers permanent migration from South Asia to the traditional receivers; South Asian asylum seekers in Europe; South Asian refugees, illegal migrants, migrant workers (flows and destinations), the stock of contract migrant workers (and their characteristics); returnee migrant workers; and skill levels. Analysis is provided of macro level determinants of emigrations such as gross national product (level and growth), the general demographic and social situation, labor force growth and structure, poverty and inequality, and internal and international migration. Environmental factors causing displacement in Southern Asia include floods, cyclones, river bank erosion, drought, and desertification. Global warming could displace millions of people in the region, and development projects have contributed to displacement. The remainder of the report covers political and ethnic factors, micro-factors influencing migration decision-making, the policies of sending and receiving countries, the consequences of emigration, and the potential for migration in the future.

Prevalence of multiple sclerosis in Iranian emigrants: review of the evidence.

PubMed

Nasr, Zahra; Majed, Masoud; Rostami, Abdolmohamad; Sahraian, Mohamad Ali; Minagar, Alireza; Amini, Arman; McGee, Jeanine C; Etemadifar, Masoud

2016-11-01

Iran has the highest prevalence of multiple sclerosis (MS) in the Middle East and Asia. Rate of emigration has been significantly raised among Iranians and though, multiple studies have been published on prevalence of MS among Iranian emigrants. Here we systematically reviewed these publications. We performed a comprehensive literature search was performed on April 30, 2015 in data bases of MEDLINE, EMBASE, Scopus and Google Scholar for the terms 'multiple sclerosis', 'incidence', 'prevalence', 'epidemiology', 'migration', 'emigrant', 'immigrant', 'Iran', 'Parsis' and 'Persian'. Study location, prevalence day or period, and age of at disease onset were recorded for all the included publications. Nine publications from Sweden, Canada, Norway, UK, and India were included. Only three reported age-adjusted prevalence and six reported age of disease onset. MS prevalence among Iranian emigrants varied from 21 per 100,000 people in Bombay, India in 1985 to 433 per 100,000 people in British Columbia, Canada in 2012. Five studies reported the prevalence in the region of interest, ranging from 1.33 in Bombay, India to 240 in British Columbia, Canada. Five studies also reported the prevalence of MS in the population of the destination country, and in all of them, the prevalence of MS was higher in Iranian immigrants compared to native people. Prevalence studies performed in Iran and also on Iranian emigrants indicate roles for both genetic and environmental factors in MS susceptibility. Data might indicate that living in a high-risk area increases the susceptibility to MS.

Combining band recovery data and Pollock's robust design to model temporary and permanent emigration

USGS Publications Warehouse

Lindberg, M.S.; Kendall, W.L.; Hines, J.E.; Anderson, M.G.

2001-01-01

Capture-recapture models are widely used to estimate demographic parameters of marked populations. Recently, this statistical theory has been extended to modeling dispersal of open populations. Multistate models can be used to estimate movement probabilities among subdivided populations if multiple sites are sampled. Frequently, however, sampling is limited to a single site. Models described by Burnham (1993, in Marked Individuals in the Study of Bird Populations, 199-213), which combined open population capture-recapture and band-recovery models, can be used to estimate permanent emigration when sampling is limited to a single population. Similarly, Kendall, Nichols, and Hines (1997, Ecology 51, 563-578) developed models to estimate temporary emigration under Pollock's (1982, Journal of Wildlife Management 46, 757-760) robust design. We describe a likelihood-based approach to simultaneously estimate temporary and permanent emigration when sampling is limited to a single population. We use a sampling design that combines the robust design and recoveries of individuals obtained immediately following each sampling period. We present a general form for our model where temporary emigration is a first-order Markov process, and we discuss more restrictive models. We illustrate these models with analysis of data on marked Canvasback ducks. Our analysis indicates that probability of permanent emigration for adult female Canvasbacks was 0.193 (SE = 0.082) and that birds that were present at the study area in year i - 1 had a higher probability of presence in year i than birds that were not present in year i - 1.

Spring Emigration of Natural and Hatchery Chinook Salmon and Steelhead Trout Smolts from the Imnaha River, Oregon; 1997 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blenden, Michael L.; Veach, Eric R.; Kucera, Paul A.

1998-10-01

For the fourth consecutive year, the Nez Perce Tribe, in conjunction with the Fish Passage Center, participated in the smolt monitoring program in the Imnaha River. A screw trap was used to collect emigrating natural and hatchery chinook salmon (Uncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) smolts from February 25 to June 27, 1997. A total of 270 natural chinook salmon, 10,616 hatchery chinook salmon, 864 natural steelhead trout (and 13 natural steelhead parr), and 7,345 hatchery steelhead trout smolts were captured during emigration studies on the Imnaha River. Mortality associated with trapping, handling and tagging was low: 0.37% formore » natural chinook, 0.11% for hatchery chinook, 0.11% for natural steelhead, and 0.39% for hatchery steelhead trout smolts. Natural chinook salmon smolts emigrated from the Imnaha River from February 25 to June 10 and had a mean length of 108 mm, average weight of 13 g, and mean condition factor of 1.02. The peak period of natural chinook smolt emigration, based on number of fish collected, occurred between March 25 and April 30. Hatchery reared chinook salmon smolts were collected from April 9 to May 9, with 99% of the smolts being caught within 10 days after release. Hatchery chinook smolts mean length, weight, and condition factor were 131 mm, 25.4 g, and 1.12, respectively. Emigration of natural steelhead smolts in the Imnaha River occurred between March 14 and June 25. Peak emigration occurred from May 1 to May 15. Natural steelhead smolts averaged 175 mm in fork length, 55.8 g in weight and had a mean condition factor of 1 .OO. Hatchery steelhead smolts emigrated from the Imnaha River between April 15 and June 27. Hatchery steelhead smolts averaged 210 mm in fork length, 88 g in weight and had a mean condition factor of 0.93. Spring runoff water conditions in 1997 provided above average flows for emigrating anadromous salmonid smolts. Imnaha River mean daily discharge during spring emigration ranged from 7.4 cms (260 cfs) on March 9 to 96.6 cms (3,410 cfs) on April 20 at USGS gauge 13292000, Imnaha, OR. Snake River discharge measured at the Anatone gauge station, ranged from 61.1 to 152 kcfs from April 15 to May 18. River discharge at LGR ranged from 79.6 kcfs on March 6 to 225.3 kcfs on May 18. Flows at LGR were generally greater than 100 kcfs during most of the spring runoff period, and discharge exceeded 120 kcfs from March 20-31 and April 19 to June 24. The water spill period at LGR occurred continuously from April 10 to June 29 with peak spill of 101.9 kcfs occurring on May 17.« less

[The emigration of physicians in Venezuela].

PubMed

Hernández, Tulia; Ortiz Gómez, Yamileth

2011-08-01

Ascertain the factors that could affect the intention of Venezuelan health professionals to emigrate to other countries. Exploratory study that applied a semistructured interview and survey, respectively, to a population consisting of four health professionals and 36 medical students. The interview data were analyzed by deductive and inductive categorization and the survey data by means of univariate and bivariate analysis. It was observed that 13.8% of the students generally intended to emigrate, with differences between the two study groups. It was found that work-related issues had a high motivating effect (16.6%), particularly the possibility of balancing work with personal life, better pay, access to continuing education, working in a better health system, and having the basic resources necessary for professional practice. It was determined that professional reasons had a moderate motivating effect (13.8%), whereas personal and contextual reasons had little influence (less than 3%). Although the interviews of physicians who had obtained their medical degree revealed clashes involving political and economic interests, only 5.5% of the students surveyed considered the political or economic situation a determinant in the emigration of professionals. It is recommended that the management and professional development of medical personnel be strengthened, reconciling their expectations with the legal framework and needs of the health system. A formal system for tracking the emigration of professionals and broadening the study of the causative factors at the national level should be set up, since better knowledge about the phenomena linked with emigration would help generate and support proposals to guarantee self-sufficiency with respect to human resources for health.

Influence of parental education on Honduran medical students' labour perspectives: rural work and emigration.

PubMed

Zambrano, Lysien I; Pereyra-Elías, Reneé; Reyes-García, Selvin Z; Fuentes, Itzel; Mayta-Tristán, Percy

2015-01-01

We sought to evaluate the intentions of Honduran medical students to emigrate or to work in a rural setting, and their association with parental education. We performed a cross-sectional, analytic study at a Honduran medical school. Student participants completed a structured questionnaire, which assessed their intentions to emigrate or work in a rural setting after finishing medical school and the highest level of education achieved by their parents. We calculated crude and adjusted prevalence ratios with their respective 95% confidence intervals. Of 868 surveys distributed, 564 were completed. The mean age of the participants was 21 (standard deviation 3) years, and 62.2% were female. Of the respondents, 16.6% intended to emigrate to work and 11.2% intended to work in a rural setting. Higher paternal education (i.e., technical, university and postgraduate training) was associated with a higher rate of intention to emigrate. Students whose fathers underwent postgraduate education were less likely to intend to work in a rural setting. For maternal education, only the postgraduate level was associated with the outcomes in some of the tested models. The frequency of students intending to emigrate was relatively low. However, the frequency of students being willing to work in rural settings was also low. Students whose parents had higher levels of education were more likely to intend to work abroad and less likely to intend to work in a rural area. These factors should be considered in medical schools' selection processes to improve retention and ensure adequate distribution of physicians.

Predictable interregional movements by female northern pintails during winter

USGS Publications Warehouse

Cox, R.R.; Afton, A.D.

2000-01-01

Factors influencing initiation of regional and interregional movements by nonbreeding ducks are poorly understood, especially during winter. During winters 1990-1991 through 1992-1993, we radiotagged 347 female Northern Pintails (Anas acuta) in southwestern Louisiana and monitored their movements to three regions: (1) the Gulf Coast Region of Louisiana and Texas (outside of southwestern Louisiana), (2) the Rice Prairie Region of Texas, and (3) the Mississippi Alluvial Valley. We found that adult females were 1.9 times more likely than were immatures to emigrate from southwestern Louisiana during winter. During winters 1990-1991 and 1991-1992, females were more likely to emigrate during stormy than during fair weather, whereas they were more likely to emigrate during fair weather in 1992-1993. Females were more likely to emigrate during duck-hunting seasons than during nonhunting seasons, regardless of weather. Daily emigration probabilities did not differ in relation to body condition when released (body mass adjusted for body size) or to number of previous emigration events. Each winter, large numbers of females consistently moved from the Gulf Coast Region to areas with abundant rice (Oryza sativa) agriculture within the Mississippi Alluvial Valley. We conclude that destination of interregional movements by this population of Northern Pintails is highly predictable, and that initiation of such movements is influenced by female age and long-term winter precipitation patterns in the Mississippi Alluvial Valley. Furthermore, timing of these movements is predictable, based not on calendar date, but rather on duck-hunting seasons and, usually, the environmental cues to habitat availability provided by stormy weather.

Bulgarian Turkish emigration and return.

PubMed

Vasileva, D

1992-01-01

The main factors which determined the 1989 migration of Turks in Bulgaria back to Turkey are discussed. Background history is provided. After World War I, Turks in bulgaria comprised 10% of the total population. Bulgarian policy had been, up to the 1980s to send Rumelian Turks back, but the policy after 1980 was one of a national revival process to integrate Turks into the developed socialist society. Muslim traditions, customs, and Turkish language were interfered with. International disfavor resulted. In May 1989, the Communist Party declared, in an effort to show democratic ideals, open borders. Thus began the new emigration wave. 369,839 people fled to the Turkish border. 43% of the 9.47 ethnic Turks in bulgaria went to Turkey within 4 months. The numbers decreased in November, and soon after the communist regime ended. New laws were adopted allowing Turks to assume their original Turkish names. The huge migration was clearly political, and as such, the emigrant Turks should be determined as refugees and asylum seekers. The provocation of ethnic Turks was used by the communist regime to solve potential social conflicts. Not only did Turks flee to escape from violence or for religious, cultural, and moral reasons but also due to free market initiatives begun in Turkey in the early 1980s which improved Turkish quality of life. Food and consumer goods were cheaper and economic advantages were perceived. Emigrants were primarily peasants with lower levels of education, professional qualifications, and labor skills. 154,937 (42%) returned to bulgaria and 58% stayed in Turkey to comprise 25% of the former Turkish population. During this period, tensions between countries was high.l Bulgarians actively encouraged emigration and Turkey welcomed it. The emigrants to Turkey were seen as foreigners (muhacir or gocmen) but were received with good will and were readily accepted into menial positions. Emigrants were confronted with political, linguistic, and cultural differences. The unifying factor was the Islamic religion. For those returning to Bulgaria, the change in regime meant the government worked to solve the emigrants' housing problems and teaching Turkish in primary and secondary schools. The result of this massive migration has been a change in the demographics and social structure of Bulgaria, and the realization that forceful migration is inefficient in solving problems.

Migration intentions and illicit substance use among youth in central Mexico.

PubMed

Marsiglia, Flavio Francisco; Kulis, Stephen; Hoffman, Steven; Calderón-Tena, Carlos Orestes; Becerra, David; Alvarez, Diana

2011-01-01

This study explored intentions to emigrate and substance use among youth (ages 14-24) from a central Mexico state with high emigration rates. Questionnaires were completed in 2007 by 702 students attending a probability sample of alternative secondary schools serving remote or poor communities. Linear and logistic regression analyses indicated that stronger intentions to emigrate predicted greater access to drugs, drug offers, and use of illicit drugs (marijuana, cocaine, inhalants), but not alcohol or cigarettes. Results are related to the healthy migrant theory and its applicability to youth with limited educational opportunities. The study's limitations are noted.

Emigration from Israel 1950-1981: a simulation study.

PubMed

Jacobsen, C; Bronson, R

1988-01-01

"Using our mathematical model of a general theory of normative regulation, we have reproduced over 80% of the variance in the cumulative percentages of emigrants [from Israel], as well as the yearly percentages from 1950 to 1981. These results suggest that, except for a limited period following the 'Six-Day War' of 1967, no situation-specific explanations are needed to account for the trends in emigration from Israel, and the phenomenon can be adequately accounted for by the general theory of normative regulation in modern industrialized societies. Some practical conclusions to mitigate the process are drawn from these findings." excerpt

Immigration, Work, and Health: A Literature Review of Immigration Between Mexico and the United States

PubMed Central

Flynn, Michael A.; Carreón, Tania; Eggerth, Donald E.; Johnson, Antoinette I.

2015-01-01

Understanding the influence someone’s job or career has on their health goes beyond the physical, emotional and social hazards, risks and conditions that they face at work. One’s job or career also exerts a significant influence over other aspects of life that contribute or detract from their health and that of their family. Work is the major incentive for Latin American migration to the United States. Latino immigrants experience increasingly poorer outcomes for physical health and chronic diseases the longer they remain in the U.S. The strong link between work and immigration suggests that, for many Latin Americans, immigration can be understood as a career path which puts them, and their family members, in situations that can change their physical, emotional, and social health as a condition of their employment. Given the large number of Latin Americans who emigrate for work, it is essential that the unique physical, mental and social impacts of emigration are accounted for when working with clients impacted by emigration at the individual, family and community level as well as those social workers practicing at the system level. This paper is a literature review that explores the impact that emigrating for work has on the health of those that emigrate and their family members that stay behind. PMID:28260831

Take-Off Time of the First Generation of the Overwintering Small Brown Planthopper, Laodelphax striatellus in the Temperate Zone in East Asia

PubMed Central

Sanada-Morimura, Sachiyo; Otuka, Akira; Matsumura, Masaya; Etoh, Tomoki; Zhu, Yeqin; Zhou, Yijun; Zhang, Gufeng

2015-01-01

Overseas migration of the small brown planthopper, Laodelphax striatellus (Fallén), occurs during the winter wheat harvest season in East Asia. Knowing the take-off time of emigrating L. striatellus is crucial for predicting such migrations with a simulation technique because winds, carriers of migratory insects, change continuously. Several methods were used in China and Japan from late May to early June 2012 and again in 2013 to identify the precise timing of take-off. These methods included: a tow net trap mounted to a pole at 10 m above the ground, a helicopter-towed net trap, and a canopy trap (which also had video monitoring) set over wheat plants. Laodelphax striatellus emigrated from wheat fields mainly in the early evening, before dusk. The insects also emigrated during the daytime but rarely emigrated at dawn, showing a pattern that is unlike the bimodal emigration at dusk and dawn of two other rice planthoppers, the brown planthopper, Nilaparvata lugens (Stål), and the white-backed planthopper, Sogatella furcifera (Horváth). There was no significant difference in the temporal pattern of take-off behavior between females and males of Japanese L. striatellus populations. PMID:25780936

Motivational goals, group identifications, and psychosocial adjustment of returning migrants: The case of Jews returning to Russia.

PubMed

Tartakovsky, Eugene; Patrakov, Eduard; Nikulina, Marina

2017-12-01

The present study investigated the motivational goals, group identifications, and psychosocial adjustment of Jews who returned to Russia after emigrating from the republics of the Former Soviet Union to different countries (n = 151). To gain a deeper understanding of these returning migrants, their traits were compared with those of Jews living in Russia who did not emigrate (n = 935). Compared to locals, returnees reported a higher preference for the openness to change and self-enhancement values and a lower preference for the conservation values; there was no difference in the self-transcendence values. Returning migrants had a relatively weak affiliation with the home country: they had a weaker identification with the home country than with the country of emigration, their identification with Russians was weaker than that among Jews who did not emigrate from Russia, and their intention to emigrate (again) from Russia was greater than that among locals. However, the Jewish identification of returning migrants was similar to that of locals. The adjustment of returning migrants varied across different dimensions: their economic adjustment was better than that of locals; however, the interpersonal adjustment of returnees was less successful than among locals. © 2016 International Union of Psychological Science.

Influence of electron injection into 27 cm audio plasma cell on the plasma diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haleem, N. A.; Ragheb, M. S.; Zakhary, S. G.

2013-08-15

In this article, the plasma is created in a Pyrex tube (L = 27 cm, φ= 4 cm) as a single cell, by a capacitive audio frequency (AF) discharge (f = 10–100 kHz), at a definite pressure of ∼0.2 Torr. A couple of tube linear and deviating arrangements show plasma characteristic conformity. The applied AF plasma and the injection of electrons into two gas mediums Ar and N{sub 2} revealed the increase of electron density at distinct tube regions by one order to attain 10{sup 13}/cm{sup 3}. The electrons temperature and density strengths are in contrast to each other. Whilemore » their distributions differ along the plasma tube length, they show a decaying sinusoidal shape where their peaks position varies by the gas type. The electrons injection moderates electron temperature and expands their density. The later highest peak holds for the N{sub 2} gas, at electrons injection it changes to hold for the Ar. The sinusoidal decaying density behavior generates electric fields depending on the gas used and independent of tube geometry. The effect of the injected electrons performs a responsive impact on electrons density not attributed to the gas discharge. Analytical tools investigate the interaction of the plasma, the discharge current, and the gas used on the electrodes. It points to the emigration of atoms from each one but for greater majority they behave to a preferred direction. Meanwhile, only in the linear regime, small percentage of atoms still moves in reverse direction. Traces of gas atoms revealed on both electrodes due to sheath regions denote lack of their participation in the discharge current. In addition, atoms travel from one electrode to the other by overcoming the sheaths regions occurring transportation of particles agglomeration from one electrode to the other. The electrons injection has contributed to increase the plasma electron density peaks. These electrons populations have raised the generated electrostatic fields assisting the elemental ions emigration to a preferred electrode direction. Regardless of plasma electrodes positions and plasma shape, ions can be departed from one electrode to deposit on the other one. In consequence, as an application the AF plasma type can enhance the metal deposition from one electrode to the other.« less

Unemployment of the educated and emigration of post-secondary graduates from the LDCs.

PubMed

Blomqvist, A G

1985-01-01

The author examines the emigration of educated individuals from developing countries and reviews selected approaches to the study of international human capital flows. Attention is then given to two policy issues: the financing of postsecondary education and an international brain drain tax. The following factors are identified as critical in their impact on educated worker migration: "(a) the rigidity or flexibility of the wage in the market for the services of educated labour; (b) the extent of government subsidy (explicit or implicit) of the cost of post-secondary education; (c) the extent of responsiveness of the investment in education to the private return on such investment or its being exogenously controlled by the government; and (d) the type of restrictions (if any) imposed by the receiving industrialized countries on the migration flows from the LDCs." Comments by M. Ali Khan on a previous article by Blomqvist on the subject are also included (pp. 655-6). excerpt

Inhibiting focal adhesion kinase (FAK) blocks IL-4 induced VCAM-1 expression and eosinophil recruitment in vitro and in vivo.

PubMed

Aulakh, Gurpreet K; Petri, Björn; Wojcik, Katarzyna M; Colarusso, Pina; Lee, James J; Patel, Kamala D

2018-04-06

Leukocyte recruitment plays a critical role during both normal inflammation and chronic inflammatory diseases, and ongoing studies endeavor to better understand the complexities of this process. Focal adhesion kinase (FAK) is well known for its role in cancer, yet it also has been shown to regulate aspects of neutrophil and B16 melanoma cell recruitment by rapidly influencing endothelial cell focal adhesion dynamics and junctional opening. Recently, we found that FAK related non-kinase (FRNK), a protein that is often used as a FAK dominant negative, blocked eosinophil transmigration by preventing the transcription of vascular cell adhesion molecule-1 (VCAM-1) and eotaxin-3 (CCL26). Surprisingly, the blocking occurred even in the absence of endogenous FAK. To better understand the role of FAK in leukocyte recruitment, we used a FAK-specific inhibitor (PF-573228) and determined the effect on IL-4 induced eosinophil recruitment in vitro and in vivo. PF-573228 prevented the expression of VCAM-1 and CCL26 expression in IL-4-stimulated human endothelial cells in vitro. As a result, eosinophil adhesion and transmigration were blocked. PF-572338 also prevented IL-4-induced VCAM-1 expression in vivo. Using brightfield intravital microscopy, we found that PF-573228 decreased leukocyte rolling flux, adhesion, and emigration. We specifically examined eosinophil recruitment in vivo by using an eosinophil-GFP reporter mouse and found PF-573228 attenuated eosinophil emigration. This study reveals that a FAK inhibitor influences inflammation through its action on eosinophil recruitment. ©2018 Society for Leukocyte Biology.

Salmon Supplementation Studies in Idaho Rivers; Idaho Supplementation Studies, 2000-2001 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beasley, Chris; Tabor, R.A.; Kinzer, Ryan

2003-04-01

This report summarizes brood year 1999 juvenile production and emigration data and adult return information for 2000 for streams studied by the Nez Perce Tribe for the cooperative Idaho Salmon Supplementation Studies in Idaho Rivers (ISS) project. In order to provide inclusive juvenile data for brood year 1999, we include data on parr, presmolt, smolt and yearling captures. Therefore, our reporting period includes juvenile data collected from April 2000 through June 2001 for parr, presmolts, and smolts and through June 2002 for brood year 1999 yearling emigrants. Data presented in this report include; fish outplant data for treatment streams, snorkelmore » and screw trap estimates of juvenile fish abundance, juvenile emigration profiles, juvenile survival estimates to Lower Granite Dam (LGJ), redd counts, and carcass data. There were no brood year 1999 treatments in Legendary Bear or Fishing Creek. As in previous years, snorkeling methods provided highly variable population estimates. Alternatively, rotary screw traps operated in Lake Creek and the Secesh River provided more precise estimates of juvenile abundance by life history type. Juvenile fish emigration in Lake Creek and the Secesh River peaked during July and August. Juveniles produced in this watershed emigrated primarily at age zero, and apparently reared in downstream habitats before detection as age one or older fish at the Snake and Columbia River dams. Over the course of the ISS study, PIT tag data suggest that smolts typically exhibit the highest relative survival to Lower Granite Dam (LGJ) compared to presmolts and parr, although we observed the opposite trend for brood year 1999 juvenile emigrants from the Secesh River. SURPH2 survival estimates for brood year 1999 Lake Creek parr, presmolt, and smolt PIT tag groups to (LGJ) were 27%, 39%, and 49% respectively, and 14%, 12%, and 5% for the Secesh River. In 2000, we counted 41 redds in Legendary Bear Creek, 4 in Fishing Creek, 5 in Slate Creek, 153 in the Secesh River, and 180 in Lake Creek. We recovered 19 carcasses (11 natural 8 hatchery) in Legendary Bear Creek, one hatchery carcass in Fishing Creek, zero carcasses in Slate Creek, 82 carcasses (19 of unknown origin and 63 natural) in the Secesh River, and 178 carcasses (2 hatchery 176 natural) from Lake Creek. In 2000 the majority (82%) of carcasses were recovered in index spawning reaches. Preliminary analysis of brood year 1997 PIT tag return data for the Secesh River and Lake Creek yields LGJ to Lower Granite Dam (LGD) juvenile to adult survival rates of, 0.00% for parr, 0.20% for presmolts, and 3.13% for smolts. LGJ to LGD juvenile to adult return rates for brood year 1997 Legendary Bear Creek were 2.98% for naturally produced PIT tagged smolts and 0.89% for PIT tagged supplementation smolts. No adults were detected at LGD from brood year 1997 parr released in Fishing Creek.« less

[Emigration from the Maghreb since 1946].

PubMed

Verhaeren R-e

1995-01-01

"Just after the Second World War, during the period of rapid economic growth, North African emigration, to France in particular, increases considerably. Later on, during the crisis, emigration still increases, but is directed towards other European countries. The crisis moreover reveals that these workforce migrations not only play a major role of regulation of the conditions [of] the job market, but also play a role of structural complementarity of national workforces, at least as far as certain levels of the market are concerned; and this to the extent that a high national unemployment rate can co-exist with a high rate of employment of foreign workers." (EXCERPT)

Migration Intentions and Illicit Substance Use among Youth in Central Mexico

PubMed Central

Marsiglia, Flavio Francisco; Kulis, Stephen; Hoffman, Steven; Calderón-Tena, Carlos Orestes; Becerra, David; Alvarez, Diana

2011-01-01

This study explored intentions to emigrate and substance use among youth (ages 14–24) from a central Mexico state with high emigration rates. Questionnaires were completed in 2007 by 702 students attending a probability sample of alternative secondary schools serving remote or poor communities. Linear and logistic regression analyses indicated that stronger intentions to emigrate predicted greater access to drugs, drug offers, and use of illicit drugs (marijuana, cocaine, inhalants), but not alcohol or cigarettes. Results are related to the healthy migrant theory and its applicability to youth with limited educational opportunities. The study’s limitations are noted. PMID:21955065

Restaurant-associated outbreak of typhoid fever in Maryland: identification of carrier facilitated by measurement of serum Vi antibodies.

PubMed Central

Lin, F Y; Becke, J M; Groves, C; Lim, B P; Israel, E; Becker, E F; Helfrich, R M; Swetter, D S; Cramton, T; Robbins, J B

1988-01-01

Ten cases of typhoid fever occurred between 24 August and 1 September 1986 in the vicinity of Silver Spring, Md. Shrimp salad served in a fast-food restaurant was implicated as the source of infection. Stool cultures were obtained from 104 employees, and serum Vi antibodies were assayed in 97 of the employees. Salmonella typhi was isolated from stool cultures of an 18-year-old asymptomatic female employee, who was a food handler. A high level of Vi antibodies (79.0 micrograms/ml), measured by radioimmunoassay, was found in her serum. She had emigrated from an endemic area at the age of 14 years and had visited that endemic area 2 years previously. The causal relation between the carrier and the 10 cases of typhoid fever was confirmed by a common bacteriophage type, denoted "degraded Vi resembling O," in the S. typhi isolates. This phage type is rare in the western hemisphere but common in the endemic area from which the carrier had emigrated. The high level of Vi antibody in the asymptomatic carrier, in contrast to the lower levels in the convalescent- and postimmunization-phase sera, facilitated the identification of the source infection in this outbreak. This radioimmunoassay offers a rapid and standardized method for identifying carriers of S. typhi. PMID:3384930

Critical role for the chemokine receptor CXCR6 in homeostasis and activation of CD1d-restricted NKT cells.

PubMed

Germanov, Elitza; Veinotte, Linnea; Cullen, Robyn; Chamberlain, Erin; Butcher, Eugene C; Johnston, Brent

2008-07-01

NK T (NKT) cells play important roles in the regulation of diverse immune responses. However, little is known about the mechanisms that regulate homeostasis and activation of these cells. Thymic NKT cells up-regulated the chemokine receptor CXCR6 following positive selection and migrated toward CXCL16 in vitro. However, CXCR6 was not essential for thymic development or maturation. In contrast, liver and lung NKT cells were depleted in CXCR6+/- and CXCR6-/- mice. The reduction in liver and lung NKT cells coincided with an increase in bone marrow NKT cells, suggesting a redistribution of NKT cells in CXCR6-/- animals. In wild-type mice, CXCL16 neutralization reduced accumulation of mature NK1.1+, but not immature NK1.1- NKT cell recent thymic emigrants in the liver. Given that thymic NKT cells are preferentially exported as NK1.1- cells, this suggests an additional role for CXCR6/CXCL16 in maturation or survival of immature liver NKT cells. CXCL16 blockade did not deplete resident NK1.1+ NKT cells, indicating that CXCR6/CXCL16 are not required to retain mature NKT cells in the liver. Cytokine production by liver and spleen NKT cells was impaired in CXCR6-/- mice following in vivo stimulation with alpha-galactosylceramide, implicating a novel role for CXCR6 in NKT cell activation. Reduced IFN-gamma production was not due to an intrinsic defect as production was normal following PMA and ionomycin stimulation. Preformed transcripts for IL-4, but not IFN-gamma, were reduced in CXCR6-/- liver NKT cells. These data identify critical roles for CXCR6/CXCL16 in NKT cell activation and the regulation of NKT cell homeostasis.

Linkages among climate change, crop yields and Mexico–US cross-border migration

PubMed Central

Feng, Shuaizhang; Krueger, Alan B.; Oppenheimer, Michael

2010-01-01

Climate change is expected to cause mass human migration, including immigration across international borders. This study quantitatively examines the linkages among variations in climate, agricultural yields, and people's migration responses by using an instrumental variables approach. Our method allows us to identify the relationship between crop yields and migration without explicitly controlling for all other confounding factors. Using state-level data from Mexico, we find a significant effect of climate-driven changes in crop yields on the rate of emigration to the United States. The estimated semielasticity of emigration with respect to crop yields is approximately −0.2, i.e., a 10% reduction in crop yields would lead an additional 2% of the population to emigrate. We then use the estimated semielasticity to explore the potential magnitude of future emigration. Depending on the warming scenarios used and adaptation levels assumed, with other factors held constant, by approximately the year 2080, climate change is estimated to induce 1.4 to 6.7 million adult Mexicans (or 2% to 10% of the current population aged 15–65 y) to emigrate as a result of declines in agricultural productivity alone. Although the results cannot be mechanically extrapolated to other areas and time periods, our findings are significant from a global perspective given that many regions, especially developing countries, are expected to experience significant declines in agricultural yields as a result of projected warming. PMID:20660749

Investment, population growth and GNP as determinants of US immigration.

PubMed

Kritz, M M

1998-09-01

Northern countries typically attract migrants from poorer countries because of the formers' high wage rates and demand for labor. In particular, the US receives large numbers of legal migrants from almost every country and region of the world. This paper explores the determinants of permanent emigration to the US during 1989-93 using data drawn from the US Immigration and Naturalization Service (INS) Annual Tapes for the period. The analysis is restricted to only legal migration from 150 countries, and specifically investigates whether emigration to the US during 1989-93 can be accounted for by demographic and economic conditions in sending countries, or by levels of US investment in sending countries. No support is found for claims that rapid population growth and US investment fuel US immigration; emigration is comparatively far lower from countries experiencing rapid population growth and not significantly correlated with US investment, while the US typically invests the most in the more developed countries which send relatively few migrants to the US. Geographic proximity is the most important correlate of migration, followed by the population size of sending countries, which is negatively related to emigration. Some evidence was found that emigration will decrease as countries develop. Who a country decides to admit and how many people are admitted depend mainly upon public policy and very little upon the economic and demographic conditions of sending countries.

Linkages among climate change, crop yields and Mexico-US cross-border migration.

PubMed

Feng, Shuaizhang; Krueger, Alan B; Oppenheimer, Michael

2010-08-10

Climate change is expected to cause mass human migration, including immigration across international borders. This study quantitatively examines the linkages among variations in climate, agricultural yields, and people's migration responses by using an instrumental variables approach. Our method allows us to identify the relationship between crop yields and migration without explicitly controlling for all other confounding factors. Using state-level data from Mexico, we find a significant effect of climate-driven changes in crop yields on the rate of emigration to the United States. The estimated semielasticity of emigration with respect to crop yields is approximately -0.2, i.e., a 10% reduction in crop yields would lead an additional 2% of the population to emigrate. We then use the estimated semielasticity to explore the potential magnitude of future emigration. Depending on the warming scenarios used and adaptation levels assumed, with other factors held constant, by approximately the year 2080, climate change is estimated to induce 1.4 to 6.7 million adult Mexicans (or 2% to 10% of the current population aged 15-65 y) to emigrate as a result of declines in agricultural productivity alone. Although the results cannot be mechanically extrapolated to other areas and time periods, our findings are significant from a global perspective given that many regions, especially developing countries, are expected to experience significant declines in agricultural yields as a result of projected warming.

78 FR 54909 - Notice of Availability of the Proposed Winnemucca District Resource Management Plan and Final...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-06

... Rock Desert-Highrock Canyon, Emigrant Trails National Conservation Area (NCA), except for... Rock Desert-High Rock Canyon Emigrant Trails National Conservation Area and Associated Wilderness, and..., closed, or subject to special stipulations or mitigation measures relating to minerals; and management of...

The Bounded Polity: The Limits to Mexican Emigrant Political Participation

ERIC Educational Resources Information Center

Waldinger, Roger; Soehl, Thomas

2013-01-01

International migration yields pervasive cross-border social engagements, yet homeland political involvements are modest to minimal. This contrast reflects the ways in which the distinctive characteristics of expatriate political life impede participation in the polity that emigrants have left behind. As polities are bounded, moving to the…

MHC drives TCR repertoire shaping, but not maturation, in recent thymic emigrants1

PubMed Central

Houston, Evan G.; Fink, Pamela J.

2009-01-01

After developing in the thymus, recent thymic emigrants (RTEs) enter the lymphoid periphery and undergo a maturation process as they transition into the mature naïve (MN) T cell compartment. This maturation presumably shapes RTEs into a pool of T cells best fit to function robustly in the periphery without causing autoimmunity; however, the mechanism and consequences of this maturation process remain unknown. Using a transgenic mouse system that specifically labels RTEs, we tested the influence of MHC molecules, key drivers of intrathymic T cell selection and naive peripheral T cell homeostasis, in shaping the RTE pool in the lymphoid periphery. We found that the TCRs expressed by RTEs are skewed to longer CDR3 regions compared to those of MN T cells, suggesting that MHC does streamline the TCR repertoire of T cells as they transition from the RTE to the MN T cell stage. This conclusion is borne out in studies in which the representation of individual TCRs was followed as a function of time since thymic egress. Surprisingly, we found that MHC is dispensable for the phenotypic and functional maturation of RTEs. This is an author-produced version of a manuscript accepted for publication in The Journal of Immunology (The JI). The American Association of Immunologists, Inc. (AAI), publisher of The JI, holds the copyright to this manuscript. This version of the manuscript has not yet been copyedited or subjected to editorial proofreading by The JI; hence, it may differ from the final version published in The JI (online and in print). AAI (The JI) is not liable for errors or omissions in this author-produced version of the manuscript or in any version derived from it by the U.S. National Institutes of Health or any other third party. The final, citable version of record can be found at www.jimmunol.org PMID:19915060

Emigration of Natural and Hatchery Naco x (Chinook salmon; Oncorhynchus tshawytscha) and Heeyey (Steelhead; Oncorhynchus mykiss) Smolts from the Imnaha River, Oregon from 5 October 2006 to 21 June 2007, Annual Report 2007.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michaels, Brian; Espinosa, Neal

2009-02-18

This report summarizes the Nez Perce Tribe (NPT) Department of Fisheries Resources Management (DFRM) results for the Lower Snake River Compensation Plan (LSRCP) Hatchery Evaluation studies and the Imnaha River Smolt Monitoring Program (SMP) for the 2007 smolt migration from the Imnaha River, Oregon. These studies are closely coordinated and provide information about juvenile natural and hatchery spring/summer Naco x (Chinook Salmon; Oncorhynchus tshawytscha) and Heeyey (steelhead; O. mykiss) biological characteristics, emigrant timing, survival, arrival timing and travel time to the Snake River dams and McNary Dam (MCD) on the Columbia River. These studies provide information on listed Naco xmore » (Chinook salmon) and Heeyey (steelhead) for the Federal Columbia River Power System (FCRPS) Biological Opinion (NMFS 2000). The Lower Snake River Compensation Plan program's goal is to maintain a hatchery production program of 490,000 Naco x (Chinook salmon) and 330,000 Heeyey (steelhead) for annual release in the Imnaha River (Carmichael et al. 1998, Whitesel et al. 1998). These hatchery releases occur to compensate for fish losses due to the construction and operation of the four lower Snake River hydroelectric facilities. One of the aspects of the LSRCP hatchery evaluation studies in the Imnaha River is to determine natural and hatchery Naco x (Chinook salmon) and Heeyey (steelhead) smolt performance, emigration characteristics and survival (Kucera and Blenden 1998). A long term monitoring effort was established to document smolt emigrant timing and post release survival within the Imnaha River, estimate smolt survival downstream to McNary Dam, compare natural and hatchery smolt performance, and collect smolt-to-adult return information. This project collects information for, and is part of, a larger effort entitled Smolt Monitoring by Federal and Non-Federal Agencies (BPA Project No. 198712700). This larger project provides data on movement of smolts out of major drainages and past dams on the Snake River and Columbia River. In season indices of migration strength and migration timing are provided for the run-at large at key monitoring sites. Marked smolts are utilized to measure travel time and estimate survival through key index reaches. Fish quality and descaling measures are recorded at each monitoring site and provide indicators of the health of the run. Co-managers in the Imnaha River subbasin (Ecovista 2004) have identified the need to collect information on life history, migration patterns, juvenile emigrant abundance, reach specific smolt survivals, and Smolt-to-Adult Return rates (SAR's) for both Heeyey (steelhead) and Naco x (Chinook salmon) smolts. The current study provides information related to the majority of the high priority data needs. Current funding does not allow for determination of a total (annual) juvenile emigrant abundance and lack of adult passive integrated transponder (PIT) tag detectors at the mouth of the Imnaha River results in the inability to calculate tributary specific SAR's. Information is shared with the Fish Passage Center (FPC) on a real time basis during the spring emigration period. The Bonneville Power Administration (BPA) and the United States Fish and Wildlife Service (USFWS) contracted the NPT to monitor emigration timing and tag up to 19,000 emigrating natural and hatchery Naco x (Chinook salmon) and Heeyey (steelhead) smolts from the Imnaha River with passive integrated transponder (PIT) tags. The completion of trapping in the spring of 2007 marked the 16th year of emigration studies on the Imnaha River, and the 14th year of participating in the FPC smolt monitoring program. Monitoring and evaluation objectives were to: (1) Evaluate effects of flow, temperature and other environmental factors on juvenile migration timing. (2) Determine emigration timing, travel time, and in-river survival of PIT tagged hatchery Naco x (Chinook salmon) smolts released at the Imnaha River acclimation facility to the Imnaha River juvenile migration trap. (3) Monitor the daily catch and biological characteristics of juvenile Naco x (Chinook salmon) and Heeyey (steelhead) smolts collected at the Imnaha River screw trap. (4) Determine spring emigration timing of Naco x (Chinook salmon) and Heeyey (steelhead) smolts collected at the Imnaha River juvenile migration trap. (5) Compare emigration characteristics and survival rates of natural fall and spring tagged juvenile Naco x (Chinook salmon). (6) Determine arrival timing, travel time and estimated survival of PIT tagged natural and hatchery Naco x (Chinook salmon) and natural and hatchery Heeyey (steelhead) smolts from the Imnaha River to Snake and Columbia River dams.« less

Physicists' Forced Migrations under Hitler

NASA Astrophysics Data System (ADS)

Beyerchen, Alan

2011-03-01

When the Nazis came to power in early 1933 they initiated formal and informal measures that forced Jews and political opponents from public institutions such as universities. Some physicists retired and others went into industry, but most emigrated. International communication and contact made emigration a viable option despite the desperate economic times in the Great Depression. Another wave of emigrations followed the annexation of Austria in 1938. Individual cases as well as general patterns of migration and adaptation to new environments will be examined in this presentation. One important result of the forced migrations was that many of the physicists expelled under Hitler played important roles in strengthening physics elsewhere, often on the Allied side in World War II.

The role of ethnic relations and education systems in migration from Southeast Asia to Australia.

PubMed

Sullivan, G; Gunasekaran, S

1993-08-01

"After a brief discussion of the geographical, cultural, and historical characteristics of Southeast Asia [and Hong Kong], a review is provided of the evolution of Australian immigration policy which, in our view, is a strong pull factor. This is followed by stock and flow analyses of Asian-born residents in Australia. The motivations for emigration in countries which exhibit substantial emigration rates are considered next and the article ends with the conclusion that demand factors and social networks play a decisive role in the decision to emigrate." Factors affecting migration significantly include political conditions and ethnic relations in countries of origin, and educational and career opportunities in the country of destination. excerpt

Changing patterns of migration in the Adriatic region.

PubMed

Schatzer, P

1988-06-01

International migration in the Adriatic countries of Albania, Greece, Italy, San Marino, and Yugoslavia is briefly examined using data from official and other published sources. The main types of migratory movements identified by the author within the region are "1) economically motivated migration (legal and clandestine); 2) immigration of refugees for resettlement; 3) immigration with the scope of final resettlement in a third country (transit movements); [and] 4) return migration by former emigrants." excerpt

Majority Children's Evaluation of Acculturation Preferences of Immigrant and Emigrant Peers

ERIC Educational Resources Information Center

Verkuyten, Maykel; Thijs, Jochem; Sierksma, Jellie

2014-01-01

Using an experimental design, native majority group children (8-13 years, N = 842) evaluated acculturation strategies (assimilation, integration, and separation) adopted by immigrant and emigrant peers. There were medium to large effects of the perceived acculturation strategies on children's peer evaluations. Overall, assimilation was valued…

A Web-Based Resource for Investigating Environmental Change: The Emigrant Pass Observatory

ERIC Educational Resources Information Center

Davis, Michael G.; Chapman, David S.

2012-01-01

We present a user-friendly, data-driven Web site (http://thermal.gg.utah.edu/facilities/epo/) for a geothermal, climate change observatory that is educational for the general public, students, and researchers alike. The Emigrant Pass Observatory (EPO), located in the Grouse Creek Mountains in northwestern Utah, gathers both meteorological data…

The Uncertain Connection: Free Trade and Rural Mexican Migration to the United States.

ERIC Educational Resources Information Center

Cornelius, Wayne A.; Martin, Philip L.

1993-01-01

Argues that it is easy to overestimate the additional emigration from rural Mexico that could occur as a result of North American Free Trade Agreement (NAFTA) related economic restructuring in Mexico. Four major reasons why Mexican emigration may not increase dramatically are suggested. Phase-in recommendations related to implementation are…

Migration as an Agent of Change in Caribbean Island Ecosystems.

ERIC Educational Resources Information Center

Marshall, Dawn

1982-01-01

There is need to assess the impact of migration on the Caribbean ecosystems. As a 150-year-old institution, emigration is related to the carrying capacity of the islands and the need to export the surplus population when capacity is threatened. Emigration, however, is a deterrent to development and individual independence. (KC)

Influential Factors in Incomplete Acquisition and Attrition of Young Heritage Speakers' Vocabulary Knowledge

ERIC Educational Resources Information Center

Gharibi, Khadijeh; Boers, Frank

2017-01-01

This study investigates whether young heritage speakers, either simultaneous or sequential bilinguals, have limited vocabulary knowledge in their family language compared to matched monolingual counterparts and, if so, what factors help to account for this difference. These factors include age, age at emigration, length of emigration, frequency of…

Reintegration of Emigrant Manpower and Promotion of Local Opportunities for Development (REMPLOD)

ERIC Educational Resources Information Center

Penninx, Rinus; And Others

1976-01-01

The REMPLOD project (Reintegration of Emigrant Manpower and the Promotion of Local Opportunities for Development) investigates ways in which foreign workers can contribute to development processes in their countries of origin (Morocco, Tunisia and Turkey). Three experts involved with the Turkish project make recommendations on the Turkish-Dutch…

Russian women emigrées in psychology: informal Jewish networks.

PubMed

Woodward, William R

2010-05-01

This paper uses archival sources and autobiographies to give a fuller account of the lives of three Russian women psychologists, each of whom voluntarily emigrated several years before the Third Reich. As such, their stories contribute to gender history, emigration history, and ethnic history. The characteristics of second-generation women in psychology seem to apply to this sample; they accepted applied or secondary positions in psychology or allied fields and came late to tenure-track positions. Some first-generation characteristics fit them also: choosing career over marriage, accepting the "family claim," and living "fractured lives." Emigrée history reveals that these women found careers in the United States that could not have happened in the smaller, more restricted higher education networks of Europe. Female friendships and family ties to the Old World sustained them. All struggled with professional networking and had varying success, depending heavily upon the patronage of sympathetic male psychologists. Ethnic history shows that none identified strongly with Judaism, yet all benefited from Jewish mentors and networks of patronage. Evidence of gendered or racial discrimination in hiring practices is sparse, though it surely existed.

Restricted emigration, system inescapability, and defense of the status quo: system-justifying consequences of restricted exit opportunities.

PubMed

Laurin, Kristin; Shepherd, Steven; Kay, Aaron C

2010-08-01

The freedom to emigrate at will from a geographic location is an internationally recognized human right. However, this right is systematically violated by restrictive migration policies. In three experiments, we explored the psychological consequences of violating the right to mobility. Our results suggest that, ironically, restricted freedom of movement can lead to increased system justification (i.e., increased support of the status quo). In Study 1, we found that participants who read that their country was difficult to leave became stronger defenders of their system's legitimacy than before, even in domains unrelated to emigration policy (e.g., gender relations). In Study 2, we demonstrated that this increased system defense was the result of a motivated process. In Study 3, we broadened the scope of this psychological phenomenon by conceptually replicating it using a different system (participants' university) and measure of system defense. The importance of these two findings-the first experimental demonstration of the psychological consequences of restrictive emigration policies and the introduction of a novel psychological phenomenon-is discussed.

Forced emigration, favourable outcomes.

PubMed

Pearn, J

2001-10-01

The discipline of public health and preventive medicine in Australia and New Zealand had its genesis in the advocacy of 18th and 19th century military pioneers. Military (Royal Navy and British Army) surgeons were posted to Australia as part of their non-discretionary duty. Civilian doctors emigrated variously for adventure, escapism and gold fever. One group, a particularly influential group disproportionate to their numbers, came in one sense as forced emigrants because of chronic respiratory disease in general, and tuberculosis in particular. Tuberculosis was an occupational hazard of 19th century medical and surgical practice throughout western Europe. This paper analyses six examples of such emigration which had, perhaps unforeseen at the time, significant results in the advancement of public health. Such emigration was in one sense voluntary, but in another was forced upon the victims in their quest for personal survival. In Australia, such medical individuals became leading advocates and successful catalysts for change in such diverse fields as social welfare, public health, the preventive aspects of medical practice, child health, nutrition and medical education. A number of such public health pioneers today have no physical memorials; but their influence is to be seen in the ethos of medical practice in Australia and New Zealand today. Their memory is further perpetuated in the names of Australian native wildflowers and trees that symbolise not only a healthy environment but the long-term investment, accrued with interest, of the institution of public health measures for which their advocacy achieved much success.

α4-Integrin Mediates Neutrophil-Induced Free Radical Injury to Cardiac Myocytes

PubMed Central

Poon, Betty Y.; Ward, Christopher A.; Cooper, Conan B.; Giles, Wayne R.; Burns, Alan R.; Kubes, Paul

2001-01-01

Previous work has demonstrated that circulating neutrophils (polymorphonuclear leukocytes [PMNs]) adhere to cardiac myocytes via β2-integrins and cause cellular injury via the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase enzyme system. Since PMNs induced to leave the vasculature (emigrated PMNs) express the α4-integrin, we asked whether (a) these PMNs also induce myocyte injury via NADPH oxidase; (b) β2-integrins (CD18) still signal oxidant production, or if this process is now coupled to the α4-integrin; and (c) dysfunction is superoxide dependent within the myocyte or at the myocyte–PMN interface. Emigrated PMNs exposed to cardiac myocytes quickly induced significant changes in myocyte function. Myocyte shortening was decreased by 30–50% and rates of contraction and relaxation were reduced by 30% within the first 10 min. Both α4-integrin antibody (Ab)-treated PMNs and NADPH oxidase–deficient PMNs were unable to reduce myocyte shortening. An increased level of oxidative stress was detected in myocytes within 5 min of PMN adhesion. Addition of an anti–α4-integrin Ab, but not an anti-CD18 Ab, prevented oxidant production, suggesting that in emigrated PMNs the NADPH oxidase system is uncoupled from CD18 and can be activated via the α4-integrin. Addition of exogenous superoxide dismutase (SOD) inhibited all parameters of dysfunction measured, whereas overexpression of intracellular SOD within the myocytes did not inhibit the oxidative stress or the myocyte dysfunction caused by the emigrated PMNs. These findings demonstrate that profound molecular changes occur within PMNs as they emigrate, such that CD18 and associated intracellular signaling pathways leading to oxidant production are uncoupled and newly expressed α4-integrin functions as the ligand that signals oxidant production. The results also provide pathological relevance as the emigrated PMNs have the capacity to injure cardiac myocytes through the α4-integrin–coupled NADPH oxidase pathway that can be inhibited by extracellular, but not intracellular SOD. PMID:11238444

U-Pb Zircon Geochronology of the Emigrant Gap Composite Pluton, Northern Sierra Nevada, California: Implications for the Nevadan Orogeny

USGS Publications Warehouse

Girty, G. H.; Yoshinobu, S.; Wracher, M.D.; Girty, M.S.; Bryan, K.A.; Skinner, J.E.; McNulty, B.A.; Bracchi, K.A.; Harwood, D.S.; Hanson, R.E.

1993-01-01

The undeformed Emigrant Gap composite pluton postdates the Lower to Middle Jurassic Sailor Canyon and Middle Jurassic Tuttle Lake Formations. According to earlier workers, these latterformations contain main and late phase Nevadan-aged (155 +/-3 Ma) spaced, slaty, phyllitic, and crenulation cleavage. Recently discovered fossils indicate that the upper part of the Sailor Canyon Formation can be no older than early Bajocian and no younger than Bathonian. The Tuttle Lake Formation stratigraphically overlies the Sailor Canyon Formation and thus probably includes middle to late Bajocian and/or Bathonian strata.The results of U-Pb work suggest that the Emigrant Gap composite pluton is composed of units that range in age from 168 +/-2 Ma (latest Bathonian to early Callovian) to 163-164 Ma (late Callovian). These new data, when combined with observations summarized above, imply that the Tuttle Lake Formation is older than the undeformed oldest unit of the Emigrant Gap composite pluton (i.e., latest Bathonian or early Callovian), and thus was probably deposited and deformed sometime between middle Bajocian and middle late Bathonian time. Hence, the cleavage contained within the Sailor Canyon and Tuttle Lake Formations could not have formed during the Late Jurassic Nevadan orogeny 155 +/-3 Ma as suggested by earlier workers.Within the foothills belt, just to the west of the Emigrant Gap composite pluton, a pronounced contractional deformation occurred sometime between 200 and 163 Ma (Early to Middle Jurassic). This middle Mesozoic deformation apparently was the result of a collision between an oceanic arc and continental North America. Because of the gross similarity in timing of structures produced during this collision and structures in the wall rocks of the Emigrant Gap composite pluton, we suggest that the latter Middle Jurassic structures are also the result of arc-continent collision, albeit a slightly more continentward expression.

Movement patterns and study area boundaries: Influences on survival estimation in capture-mark-recapture studies

USGS Publications Warehouse

Horton, G.E.; Letcher, B.H.

2008-01-01

The inability to account for the availability of individuals in the study area during capture-mark-recapture (CMR) studies and the resultant confounding of parameter estimates can make correct interpretation of CMR model parameter estimates difficult. Although important advances based on the Cormack-Jolly-Seber (CJS) model have resulted in estimators of true survival that work by unconfounding either death or recapture probability from availability for capture in the study area, these methods rely on the researcher's ability to select a method that is correctly matched to emigration patterns in the population. If incorrect assumptions regarding site fidelity (non-movement) are made, it may be difficult or impossible as well as costly to change the study design once the incorrect assumption is discovered. Subtleties in characteristics of movement (e.g. life history-dependent emigration, nomads vs territory holders) can lead to mixtures in the probability of being available for capture among members of the same population. The result of these mixtures may be only a partial unconfounding of emigration from other CMR model parameters. Biologically-based differences in individual movement can combine with constraints on study design to further complicate the problem. Because of the intricacies of movement and its interaction with other parameters in CMR models, quantification of and solutions to these problems are needed. Based on our work with stream-dwelling populations of Atlantic salmon Salmo salar, we used a simulation approach to evaluate existing CMR models under various mixtures of movement probabilities. The Barker joint data model provided unbiased estimates of true survival under all conditions tested. The CJS and robust design models provided similarly unbiased estimates of true survival but only when emigration information could be incorporated directly into individual encounter histories. For the robust design model, Markovian emigration (future availability for capture depends on an individual's current location) was a difficult emigration pattern to detect unless survival and especially recapture probability were high. Additionally, when local movement was high relative to study area boundaries and movement became more diffuse (e.g. a random walk), local movement and permanent emigration were difficult to distinguish and had consequences for correctly interpreting the survival parameter being estimated (apparent survival vs true survival). ?? 2008 The Authors.

Lifecourse factors and likelihood of rural practice and emigration: a survey of Ghanaian medical students.

PubMed

Kotha, Sudha Rani; Johnson, Jennifer C; Galea, Sandro; Agyei-Baffour, Peter; Nakua, Emmanuel; Asabir, Kwesi; Kwansah, Janet; Gyakobo, Mawuli; Dzodzomenyo, Mawuli; Kruk, Margaret E

2012-01-01

Health worker shortages and maldistribution have important implications for the capacity of health systems. Ghana has one of the highest physician emigration rates in the world, and over 75% of those who remain work in Ghana's two largest cities. The aim of this study was to investigate the contribution of experiential factors across Ghanaian medical students' lifespans on intent to practice in a rural area and intent to emigrate. All fourth year medical students in Ghana were surveyed on demographics, rural and international experience, and future career plans. Key outcomes of interest were students' stated likelihood of practicing in a deprived rural area or emigrating after graduation. Lifecourse predictors of interest were parental socioeconomic status, gender, relationship status, rural and international living experience, and school of study. Bivariate and multivariate logistic regression were used to estimate associations between predictors and outcomes of interest. Of 310 eligible students, 307 (99%) participated in the survey. Of these, 228 were Ghanaian and the focus of this analysis. It was found that 131 (57.5%) were willing to work in a deprived area in Ghana and 148 (64.9%) had considered emigrating after graduation. In the multivariate regression models, willingness to work in a deprived area was predicted by male gender (OR: 2.31, 95%CI: 1.23-4.35), having lived in a rural area but never lived abroad (OR: 2.77, 95%CI: 1.08-7.13), and low parental professional and educational status (OR: 2.33, 95%CI: 1.23-4.43). Consideration of emigration was predicted by having lived abroad but never in a rural area (OR: 3.39, 95%CI: 1.15-9.97). A sub-set of 80 individuals (35%) reported that they were willing to work in a deprived area in Ghana but also considering emigration. These subjects were more likely to be male. Students with parents of a lower socioeconomic class, those with rural experience, and those without international experience are more likely to stay in Ghana and are also more likely to work in a deprived area after graduation. Selective admissions policies based on lifecourse factors combined with exposure to rural practice in medical school may have a role in increasing the number of rural physicians.

THE MECHANISM OF THE INFLAMMATORY PROCESS : III. ELECTROPHORETIC MIGRATION OF INERT PARTICLES AND BLOOD CELLS IN GELATIN SOLS AND GELS WITH REFERENCE TO LEUCOCYTE EMIGRATION THROUGH THE CAPILLARY WALL.

PubMed

Abramson, H A

1928-07-20

1. Quartz particles and certain other particles move cataphoretically in certain soft gelatin gels, with the same velocity as in the sol. The speed is a function of the true viscosity of the sol or gel, and it is See PDF for Structure apparently not altered in these soft gels by the presence of gel structure. It is proportional to the applied difference of potential. 2. This finding is compatible with the fact that certain sols undergo gelation with no increase of the true viscosity although a marked change in the apparent viscosity takes place. 3. Red cells in soft gelatin-serum gels show a distinct difference in behavior. They migrate through the sol or gel with a speed that is about twice as great as the leucocytes and quartz particles, which latter particles migrate with the same velocity. This ratio has been found to hold for serum and plasma. The absolute velocities are comparatively slightly decreased by the presence of the gel. 4. In more concentrated or stiffer gels, leucocytes, red cells and quartz particles all move at first with the same velocity. By producing mechanical softening of these gels (shearing from cataphoretic movement of the micells within the cell) the red cells presently resume their previous property of independent migration through the gel. 5. The movements of particles in gelatin gels produced by a magnetic force or the force of gravity are of a different nature than those movements produced by cataphoresis. 6. The mechanical nature of obstruction to the cataphoretic migration of leucocytes and red cells in fibrin gels is briefly described. 7. The correlation of cataphoresis of microscopic particles in gels with the order of magnitude and nature of the potential differences in the capillary wall, lends additional evidence to the theory that polymorphonuclear leucocyte emigration and migration are dependent upon these potential differences.

Nonmelanoma Skin Cancer in Nonwhite Organ Transplant Recipients.

PubMed

Pritchett, Ellen N; Doyle, Alden; Shaver, Christine M; Miller, Brett; Abdelmalek, Mark; Cusack, Carrie Ann; Malat, Gregory E; Chung, Christina Lee

2016-12-01

Organ transplant recipients have a higher incidence of skin cancer. This risk is magnified over time and with continued exposure to immunosuppression. Skin cancer in nonwhite patients is associated with greater morbidity and mortality owing to diagnosis at a more advanced stage, which suggests that nonwhite organ transplant recipients are at even higher risk. To describe demographic and clinical factors and the incidence of skin cancer in nonwhite organ transplant recipients. We performed a retrospective medical record review of patients who were organ transplant recipients (154 were white and 259 nonwhite [black, Asian, Hispanic, Pacific Islander]) seen from November 1, 2011, to April 18, 2016 at an academic referral center. Variables were analyzed and compared between racial groups, including sex, age, race/ethnicity, Fitzpatrick type, type and location of skin cancer, type of organ transplanted, time to diagnosis of skin cancer after transplantation, and history of condyloma acuminata and/or verruca vulgaris. Most of the 413 patients (62.7%) evaluated were nonwhite organ transplant recipients; 264 were men, and 149 were women. Their mean (SD) age was 60.09 (13.59) years. Nineteen skin cancers were identified in 15 patients (5.8%) representing 3 racial/ethnic groups: black (6 patients), Asian (5), and Hispanic (4). All squamous cell carcinomas in blacks were diagnosed in the in situ stage, located on sun-protected sites, and occurred in patients whose lesions tested positive for human papilloma virus (HPV) and/or who endorsed a history of condyloma acuminata or verruca vulgaris. Most skin cancers in Asians were located on sun-exposed areas and occurred in individuals who emigrated from equatorial locations. Nonwhite organ transplant recipients are at risk for developing skin cancer posttransplantation. Follow-up in a specialized transplant dermatology center and baseline total-body skin examination should be part of posttransplantation care in all organ transplant recipients, including nonwhite patients. A thorough inspection of the groin and genitalia is imperative in black organ transplant recipients. History of HPV infection, particularly in black organ transplant recipients, and sun exposure/emigration history in Asian organ transplant recipients should be documented. Vigilant photoprotection may be of lesser importance in the prevention of skin cancer in black organ transplant recipients. Risk factors for nonwhite organ transplant recipients differ between races/ethnicities and warrant further study in efforts to better counsel and prevent skin cancer in these patients.

Emigration, Generation, and Collective Memories: The Presence of the Past for Emigrants from the Former Soviet Union

ERIC Educational Resources Information Center

Corning, Amy D.

2010-01-01

Research on memory of public events consistently reveals generational effects, where individuals remember best the events from their "critical years" of adolescence and early adulthood--a phenomenon attributed to privileged encoding or retrieval of memories due to primacy of experience. Prior research, however, has not decoupled the…

Elderly Japanese emigrants to Brazil before World War II: I. Clinical profiles based on specific historical background.

PubMed

Meguro, M; Meguro, K; Caramelli, P; Ishizaki, J; Ambo, H; Chubaci, R Y; Hamada, G S; Nitrini, R; Yamadori, A

2001-08-01

To research the demographic and clinical profiles of elderly Japanese emigrants, who arrived in Brazil before World War II, in order to give them appropriate psychogeriatric care. Elderly Japanese immigrants aged 65 years and over, belonging to the Miyagi Association in the São Paulo Metropolitan Area, were targeted. They emigrated from Miyagi Prefecture to Brazil and are now living in the area. We were able to interview 166 respondents. All data were gathered using standardized interview methods covering (a) free interview about the immigration history, (b) demographics, and (c) physical status. Through the free interview, we found their immigration histories, which affected their clinical profiles. The mean age and educational level were 77.5 years and 6.3 years, respectively. Sixty per cent of them immigrated when they were younger than 14. Ninety-four per cent of them still keep Japanese nationality. Fifty-seven per cent of them usually use Japanese, while 10% of them use Portuguese. Although their emigration histories were hard, 76% of them perceived their health as being excellent or relatively good. The percentages of subjects with histories of disease were hypertension, 52.5%; cardiac disease, 20.8%; diabetes mellitus, 24.2%; and hyperlipidemia, 25.0%, which were affected by the Brazilian environment. The elderly Japanese who emigrated to Brazil before World War II have a unique historical and demographic background. Their clinical profiles cannot be fully understood without knowing their histories. They definitely need high quality international psychogeriatric care. Copyright 2001 John Wiley & Sons, Ltd.

"I Fear the Consequences to Our Animals": Emigrants and Their Livestock on the Overland Trails

ERIC Educational Resources Information Center

Ahmad, Diana L.

2012-01-01

The diaries, letters, and guidebooks written by the emigrants who crossed North America on the overland trails during the mid-nineteenth century reveal a new awareness of the animals that journeyed with them. Often written as advice to those who might follow them, the travelers worried about their animals in ways beyond what theologians and…

22 CFR 99.2 - Reporting requirements for adoption cases involving children emigrating from the United States.

Code of Federal Regulations, 2010 CFR

2010-04-01

...-Convention case, the reporting provider is the one that has child placement responsibility, as evidenced by... (generally the time the child is matched with adoptive parents); (2) Date of U.S. final adoption or date on... involving children emigrating from the United States. 99.2 Section 99.2 Foreign Relations DEPARTMENT OF...

22 CFR 99.2 - Reporting requirements for adoption cases involving children emigrating from the United States.

Code of Federal Regulations, 2014 CFR

2014-04-01

...-Convention case, the reporting provider is the one that has child placement responsibility, as evidenced by... (generally the time the child is matched with adoptive parents); (2) Date of U.S. final adoption or date on... involving children emigrating from the United States. 99.2 Section 99.2 Foreign Relations DEPARTMENT OF...

22 CFR 99.2 - Reporting requirements for adoption cases involving children emigrating from the United States.

Code of Federal Regulations, 2013 CFR

2013-04-01

...-Convention case, the reporting provider is the one that has child placement responsibility, as evidenced by... (generally the time the child is matched with adoptive parents); (2) Date of U.S. final adoption or date on... involving children emigrating from the United States. 99.2 Section 99.2 Foreign Relations DEPARTMENT OF...

22 CFR 99.2 - Reporting requirements for adoption cases involving children emigrating from the United States.

Code of Federal Regulations, 2011 CFR

2011-04-01

...-Convention case, the reporting provider is the one that has child placement responsibility, as evidenced by... (generally the time the child is matched with adoptive parents); (2) Date of U.S. final adoption or date on... involving children emigrating from the United States. 99.2 Section 99.2 Foreign Relations DEPARTMENT OF...

22 CFR 99.2 - Reporting requirements for adoption cases involving children emigrating from the United States.

Code of Federal Regulations, 2012 CFR

2012-04-01

...-Convention case, the reporting provider is the one that has child placement responsibility, as evidenced by... (generally the time the child is matched with adoptive parents); (2) Date of U.S. final adoption or date on... involving children emigrating from the United States. 99.2 Section 99.2 Foreign Relations DEPARTMENT OF...

From Emigration to Immigration: New Dawn for an Intercultural 21st Century Ireland

ERIC Educational Resources Information Center

Mutwarasibo, Fidele

2005-01-01

Within the course of a decade Ireland has emerged from being a country of emigration to a country of immigration. Since the mid-1990s, Ireland has undergone rapid economic expansion with the recent economic growth resulting in approximately 252,000 migrants entering Ireland over the last 6 years, according to the Irish Times (2003). While a large…

Emigrant Creek cattle allotment: lessons from 30 years of photomonitoring.

Treesearch

Frederick C. Hall

2005-01-01

Emigrant Creek cattle allotment is located 48 km northwest of Burns, Oregon. It was photo sampled at nine original sites, starting in 1975. Photos were taken three times per year: June 15 prior to cattle grazing, August 1 at pasture rotation, and October 1 at the end of grazing. An additional four photopoints were established following disturbance from flooding and...

[Development and application of a web-based expert system using artificial intelligence for management of mental health by Korean emigrants].

PubMed

Bae, Jeongyee

2013-04-01

The purpose of this project was to develop an international web-based expert system using principals of artificial intelligence and user-centered design for management of mental health by Korean emigrants. Using this system, anyone can access the system via computer access to the web. Our design process utilized principles of user-centered design with 4 phases: needs assessment, analysis, design/development/testing, and application release. A survey was done with 3,235 Korean emigrants. Focus group interviews were also conducted. Survey and analysis results guided the design of the web-based expert system. With this system, anyone can check their mental health status by themselves using a personal computer. The system analyzes facts based on answers to automated questions, and suggests solutions accordingly. A history tracking mechanism enables monitoring and future analysis. In addition, this system will include intervention programs to promote mental health status. This system is interactive and accessible to anyone in the world. It is expected that this management system will contribute to Korean emigrants' mental health promotion and allow researchers and professionals to share information on mental health.

On the evolution of specialization with a mechanistic underpinning in structured metapopulations.

PubMed

Nurmi, Tuomas; Parvinen, Kalle

2008-03-01

We analyze the evolution of specialization in resource utilization in a discrete-time metapopulation model using the adaptive dynamics approach. The local dynamics in the metapopulation are based on the Beverton-Holt model with mechanistic underpinnings. The consumer faces a trade-off in the abilities to consume two resources that are spatially heterogeneously distributed to patches that are prone to local catastrophes. We explore the factors favoring the spread of generalist or specialist strategies. Increasing fecundity or decreasing catastrophe probability favors the spread of the generalist strategy and increasing environmental heterogeneity enlarges the parameter domain where the evolutionary branching is possible. When there are no catastrophes, increasing emigration diminishes the parameter domain where the evolutionary branching may occur. Otherwise, the effect of emigration on evolutionary dynamics is non-monotonous: both small and large values of emigration probability favor the spread of the specialist strategies whereas the parameter domain where evolutionary branching may occur is largest when the emigration probability has intermediate values. We compare how different forms of spatial heterogeneity and different models of local growth affect the evolutionary dynamics. We show that even small changes in the resource dynamics may have outstanding evolutionary effects to the consumers.

Inference about density and temporary emigration in unmarked populations

USGS Publications Warehouse

Chandler, Richard B.; Royle, J. Andrew; King, David I.

2011-01-01

Few species are distributed uniformly in space, and populations of mobile organisms are rarely closed with respect to movement, yet many models of density rely upon these assumptions. We present a hierarchical model allowing inference about the density of unmarked populations subject to temporary emigration and imperfect detection. The model can be fit to data collected using a variety of standard survey methods such as repeated point counts in which removal sampling, double-observer sampling, or distance sampling is used during each count. Simulation studies demonstrated that parameter estimators are unbiased when temporary emigration is either "completely random" or is determined by the size and location of home ranges relative to survey points. We also applied the model to repeated removal sampling data collected on Chestnut-sided Warblers (Dendroica pensylvancia) in the White Mountain National Forest, USA. The density estimate from our model, 1.09 birds/ha, was similar to an estimate of 1.11 birds/ha produced by an intensive spot-mapping effort. Our model is also applicable when processes other than temporary emigration affect the probability of being available for detection, such as in studies using cue counts. Functions to implement the model have been added to the R package unmarked.

A Stochastic Model of Eye Lens Growth

PubMed Central

Šikić, Hrvoje; Shi, Yanrong; Lubura, Snježana; Bassnett, Steven

2015-01-01

The size and shape of the ocular lens must be controlled with precision if light is to be focused sharply on the retina. The lifelong growth of the lens depends on the production of cells in the anterior epithelium. At the lens equator, epithelial cells differentiate into fiber cells, which are added to the surface of the existing fiber cell mass, increasing its volume and area. We developed a stochastic model relating the rates of cell proliferation and death in various regions of the lens epithelium to deposition of fiber cells and lens growth. Epithelial population dynamics were modeled as a branching process with emigration and immigration between various proliferative zones. Numerical simulations were in agreement with empirical measurements and demonstrated that, operating within the strict confines of lens geometry, a stochastic growth engine can produce the smooth and precise growth necessary for lens function. PMID:25816743

Association between Kinin B1 Receptor Expression and Leukocyte Trafficking across Mouse Mesenteric Postcapillary Venules

PubMed Central

McLean, Peter G.; Ahluwalia, Amrita; Perretti, Mauro

2000-01-01

Using intravital microscopy, we examined the role played by B1 receptors in leukocyte trafficking across mouse mesenteric postcapillary venules in vivo. B1 receptor blockade attenuated interleukin (IL)-1β–induced (5 ng intraperitoneally, 2 h) leukocyte–endothelial cell interactions and leukocyte emigration (∼50% reduction). The B1 receptor agonist des-Arg9bradykinin (DABK), although inactive in saline- or IL-8–treated mice, caused marked neutrophil rolling, adhesion, and emigration 24 h after challenge with IL-1β (when the cellular response to IL-1β had subsided). Reverse transcriptase polymerase chain reaction and Western blot revealed a temporal association between the DABK-induced response and upregulation of mesenteric B1 receptor mRNA and de novo protein expression after IL-1β treatment. DABK-induced leukocyte trafficking was antagonized by the B1 receptor antagonist des-arg10HOE 140 but not by the B2 receptor antagonist HOE 140. Similarly, DABK effects were maintained in B2 receptor knockout mice. The DABK-induced responses involved the release of neuropeptides from C fibers, as capsaicin treatment inhibited the responses. Treatment with the neurokinin (NK)1 and NK3 receptor antagonists attenuated the responses, whereas NK2, calcitonin gene-related peptide, or platelet-activating factor receptor antagonists had no effect. Substance P caused leukocyte recruitment that, similar to DABK, was inhibited by NK1 and NK3 receptor blockade. Mast cell depletion using compound 48/80 reduced DABK-induced leukocyte trafficking, and DABK treatment was shown histologically to induce mast cell degranulation. DABK-induced trafficking was inhibited by histamine H1 receptor blockade. Our findings provide clear evidence that B1 receptors play an important role in the mediation of leukocyte–endothelial cell interactions in postcapillary venules, leading to leukocyte recruitment during an inflammatory response. This involves activation of C fibers and mast cells, release of substance P and histamine, and stimulation of NK1, NK3, and H1 receptors. PMID:10934225

Porcine circovirus 2 (PCV2) increases the expression of endothelial adhesion/junction molecules.

PubMed

Marks, Fernanda S; Almeida, Laura L; Driemeier, David; Canal, Cláudio; Barcellos, David E S N; Guimarães, Jorge A; Reck, José

Porcine circovirus type 2 (PCV2) is the primary causative agent of porcine circovirus disease, a complex multisystem syndrome in domestic pigs. Despite the significant economic losses caused by porcine circovirus disease, the mechanisms of pathogenesis underlying the clinical findings remain largely unclear. As various reports have highlighted the potential key role of vascular lesions in the pathogenesis of porcine circovirus disease, the aim of this work was to investigate effects of PCV2 infection on vascular endothelial cells, focusing on cell viability and expression of adhesion/junction molecules. PCV2 infection reduced endothelial cell viability, while viral infection did not affected the viability of several other classical cell lines. Also, PCV2 infection in endothelial cells displayed a dual/biphasic effect: initially, infection increased ICAM-1 expression, which can favor leukocyte recruitment and emigration to tissues and possibly inducing characteristic porcine circovirus disease inflammatory lesions; then, secondarily, infection caused an increase in zonula occludens 1 tight junction protein (ZO-1) expression, which in turn can result in difficulties for cell traffic across the endothelium and a potential impairment the immune response in peripheral tissues. These virus-induced endothelial changes could directly impact the inflammatory process of porcine circovirus disease and associated vascular/immune system disturbances. Data suggest that, among the wide range of effects induced by PCV2 on the host, endothelial modulation can be a pivotal process which can help to explain PCV2 pathogenesis in some porcine circovirus disease presentations. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Aboriginal Community Education Officers' Border Work: Culturally Safe Practices for Supporting Migrating Indigenous Students from Country into Urban and Semi-Rural Schools

ERIC Educational Resources Information Center

MacGill, Bindi

2012-01-01

Since 2001 there has been an increase in migration patterns by Indigenous families from remote communities to urban and semi-rural locations. Indigenous student emigration from remote Indigenous schools to urban and semi-rural schools is an emerging crisis as there are routinely inadequate service providers for Indigenous emigres. Migration away…

78 FR 28146 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Shrimp Fishery of the Gulf of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-14

... major period of emigration of these shrimp from Texas estuaries to the Gulf of Mexico (Gulf) so the... to project when brown shrimp in Texas bays and estuaries will reach a mean size of 3.54 in (90 mm), and begin strong emigrations out of the bays and estuaries during maximum duration ebb tides. Sampling...

Pestalozzi in Dewey's Realm? Bauhaus Master Josef Albers among the German-Speaking Emigres' Colony at Black Mountain College (1933-1949)

ERIC Educational Resources Information Center

Fussl, Karl Heinz

2006-01-01

This article deals with German academic emigres who fled Hitler after 1933 and established their refuge at the American-based Black Mountain College in North Carolina, founded as an alternative to traditional institutions of higher education in that very year. Of particular consideration are the contributions of noted Bauhaus master Josef Albers…

The cost of health professionals' brain drain in Kenya.

PubMed

Kirigia, Joses Muthuri; Gbary, Akpa Raphael; Muthuri, Lenity Kainyu; Nyoni, Jennifer; Seddoh, Anthony

2006-07-17

Past attempts to estimate the cost of migration were limited to education costs only and did not include the lost returns from investment. The objectives of this study were: (i) to estimate the financial cost of emigration of Kenyan doctors to the United Kingdom (UK) and the United States of America (USA); (ii) to estimate the financial cost of emigration of nurses to seven OECD countries (Canada, Denmark, Finland, Ireland, Portugal, UK, USA); and (iii) to describe other losses from brain drain. The costs of primary, secondary, medical and nursing schools were estimated in 2005. The cost information used in this study was obtained from one non-profit primary and secondary school and one public university in Kenya. The cost estimates represent unsubsidized cost. The loss incurred by Kenya through emigration was obtained by compounding the cost of educating a medical doctor and a nurse over the period between the average age of emigration (30 years) and the age of retirement (62 years) in recipient countries. The total cost of educating a single medical doctor from primary school to university is 65,997 US dollars; and for every doctor who emigrates, a country loses about 517,931 US dollars worth of returns from investment. The total cost of educating one nurse from primary school to college of health sciences is 43,180 US dollars; and for every nurse that emigrates, a country loses about 338,868 US dollars worth of returns from investment. Developed countries continue to deprive Kenya of millions of dollars worth of investments embodied in her human resources for health. If the current trend of poaching of scarce human resources for health (and other professionals) from Kenya is not curtailed, the chances of achieving the Millennium Development Goals would remain bleak. Such continued plunder of investments embodied in human resources contributes to further underdevelopment of Kenya and to keeping a majority of her people in the vicious circle of ill-health and poverty. Therefore, both developed and developing countries need to urgently develop and implement strategies for addressing the health human resource crisis.

The cost of health professionals' brain drain in Kenya

PubMed Central

Kirigia, Joses Muthuri; Gbary, Akpa Raphael; Muthuri, Lenity Kainyu; Nyoni, Jennifer; Seddoh, Anthony

2006-01-01

Background Past attempts to estimate the cost of migration were limited to education costs only and did not include the lost returns from investment. The objectives of this study were: (i) to estimate the financial cost of emigration of Kenyan doctors to the United Kingdom (UK) and the United States of America (USA); (ii) to estimate the financial cost of emigration of nurses to seven OECD countries (Canada, Denmark, Finland, Ireland, Portugal, UK, USA); and (iii) to describe other losses from brain drain. Methods The costs of primary, secondary, medical and nursing schools were estimated in 2005. The cost information used in this study was obtained from one non-profit primary and secondary school and one public university in Kenya. The cost estimates represent unsubsidized cost. The loss incurred by Kenya through emigration was obtained by compounding the cost of educating a medical doctor and a nurse over the period between the average age of emigration (30 years) and the age of retirement (62 years) in recipient countries. Results The total cost of educating a single medical doctor from primary school to university is US$ 65,997; and for every doctor who emigrates, a country loses about US$ 517,931 worth of returns from investment. The total cost of educating one nurse from primary school to college of health sciences is US$ 43,180; and for every nurse that emigrates, a country loses about US$ 338,868 worth of returns from investment. Conclusion Developed countries continue to deprive Kenya of millions of dollars worth of investments embodied in her human resources for health. If the current trend of poaching of scarce human resources for health (and other professionals) from Kenya is not curtailed, the chances of achieving the Millennium Development Goals would remain bleak. Such continued plunder of investments embodied in human resources contributes to further underdevelopment of Kenya and to keeping a majority of her people in the vicious circle of ill-health and poverty. Therefore, both developed and developing countries need to urgently develop and implement strategies for addressing the health human resource crisis. PMID:16846492

The movement of people in Asia: internal, intra-regional and international migration.

PubMed

Lim, L L; Abella, M

1994-01-01

"The comprehensive overview of Asian-Pacific migration summarizes early population movements during the colonial period and describes the major types of contemporary Asian population movements: (1) environmental refugees, (2) political refugees, (3) internal population movements, (4) contract labor migration, (5) migration of permanent settlers, (6) business related movements and tourism. Projections of net international migration are given. Population growth, employment absorption and emigration pressures are likely to contribute to a large mobility potential for Asia, with significant implications for Australia." excerpt

New views on the neural crest epithelial-mesenchymal transition and neuroepithelial interkinetic nuclear migration

PubMed Central

Erickson, Carol A

2009-01-01

By developing a technique for imaging the avian neural crest epithelial-mesenchymal transition (EMT), we have discovered cellular behaviors that challenge current thinking on this important developmental event, including the probability that complete disassembly of the adherens junctions may not control whether or not a neural epithelial cell undergoes an EMT. Further, neural crest cells can adopt multiple modes of cell motility in order to emigrate from the neuroepithelium. We also gained insights into interkinetic nuclear migration (INM). For example, the movement of the nucleus from the basal to apical domain may not require microtubule motors nor an intact nuclear envelope, and the nucleus does not always need to reach the apical surface in order for cytokinesis to occur. These studies illustrate the value of live-cell imaging to elucidate cellular processes. PMID:20195454

Gone for good? An online survey of emigrant health professionals using Facebook as a recruitment tool.

PubMed

McAleese, Sara; Clyne, Barbara; Matthews, Anne; Brugha, Ruairí; Humphries, Niamh

2016-06-30

Health professionals, particularly doctors, nurses and midwives, are in high demand worldwide. Therefore, it is important to assess the future plans and likelihood of return of emigrating health professionals. Nevertheless, health professionals are, by definition, a difficult population to track/survey. This exploratory study reports on the migration intentions of a sample of doctors, nurses and midwives who had emigrated from Ireland, a high-income country which has experienced particularly high outward and inward migration of health professionals since the year 2000. Health professionals who had emigrated from Ireland were identified via snowball sampling through Facebook and invited to complete a short online survey composed of closed and open response questions. A total of 388 health professionals (307 doctors, 73 nurses and 8 midwives) who had previously worked in Ireland completed the survey. While over half had originally intended to spend less than 5 years in their destination country at the time of emigration, these intentions changed over time, with the desire to remain abroad on a permanent basis increasing from 10 to 34 % of doctor respondents. Only a quarter of doctors and a half of nurses and midwives intended to return to practice in Ireland in the future. The longer health professionals remain abroad, the less likely they are to return to their home countries. Countries should focus on the implementation of retention strategies if the 'carousel' of brain drain is to be interrupted. This would allow source countries to benefit from their investments in training health professionals, rather than relying on international recruitment to meet health system staffing needs. Improved data collection systems are also needed to track the migratory patterns and changing intentions of health professionals. Meanwhile, social networking platforms offer alternative methods of filling this information gap.

High Emigration Propensity and Low Mortality on Transfer Drives Female-Biased Dispersal of Pyriglena leucoptera in Fragmented Landscapes

PubMed Central

Awade, Marcelo; Candia-Gallardo, Carlos; Cornelius, Cintia; Metzger, Jean Paul

2017-01-01

Dispersal is a biological process performed in three stages: emigration, transfer and immigration. Intra-specific variation on dispersal behavior, such as sex-bias, is very common in nature, particularly in birds and mammals. However, dispersal is difficult to measure in the field and many hypotheses concerning the causes of sex-biased dispersal remain without empirical confirmation. An important limitation of most empirical studies is that inferences about sex-biased dispersal are based only on emigration proneness or immigration success data. Thus, we still do not know whether sex-biased immigration in fragmented landscapes occurs during emigration, transfer or in both stages. We conducted translocation and radiotracking experiments to assess i) whether inter-patch dispersal movements of a rainforest bird (Pyriglena leucoptera) is sex-biased and ii) how dispersal stages and the perceptual range of the individuals are integrated to generate dispersal patterns. Our results showed that inter-patch dispersal is sex-biased at all stages for P. leucoptera, as females not only exhibit a higher emigration propensity but are subjected to a lower risk of predation when moving through the matrix. Moreover, our data support a perceptual range of 80 m and our results showed that dispersal success decreases considerably when inter-patch distances exceeds this perceptual range. In this case, birds have a higher probability of travelling over longer routes and, as a consequence, the risk of predation increases, specially for males. Overall, results supported that assuming dispersal as a single-stage process to describe dispersal behavior may be misleading. In this way, our study advanced our understanding of processes and patterns related to inter-patch dispersal of neotropical forest birds, shedding light on potential implications for population dynamics and for the management of fragmented landscapes. PMID:28107517

Fidelity and breeding probability related to population density and individual quality in black brent geese Branta bernicla nigricans

USGS Publications Warehouse

Sedinger, J.S.; Chelgren, N.D.; Ward, D.H.; Lindberg, M.S.

2008-01-01

1. Patterns of temporary emigration (associated with non-breeding) are important components of variation in individual quality. Permanent emigration from the natal area has important implications for both individual fitness and local population dynamics. 2. We estimated both permanent and temporary emigration of black brent geese (Branta bernicla nigricans Lawrence) from the Tutakoke River colony, using observations of marked brent geese on breeding and wintering areas, and recoveries of ringed individuals by hunters. We used the likelihood developed by Lindberg, Kendall, Hines & Anderson 2001 (Combining band recovery data and Pollock's robust design to model temporary and permanent emigration. Biometrics, 57, 273-281) to assess hypotheses and estimate parameters. 3. Temporary emigration (the converse of breeding) varied among age classes up to age 5, and differed between individuals that bred in the previous years vs. those that did not. Consistent with the hypothesis of variation in individual quality, individuals with a higher probability of breeding in one year also had a higher probability of breeding the next year. 4. Natal fidelity of females ranged from 0.70 ?? 0.07-0.96 ?? 0.18 and averaged 0.83. In contrast to Lindberg et al. (1998), we did not detect a relationship between fidelity and local population density. Natal fidelity was negatively correlated with first-year survival, suggesting that competition among individuals of the same age for breeding territories influenced dispersal. Once females nested at the Tutakoke River, colony breeding fidelity was 1.0. 5. Our analyses show substantial variation in individual quality associated with fitness, which other analyses suggest is strongly influenced by early environment. Our analyses also suggest substantial interchange among breeding colonies of brent geese, as first shown by Lindberg et al. (1998).

Migration and coronary heart disease: A study of Finnish twins living in Sweden and their co-twins residing in Finland.

PubMed

Hedlund, Ebba; Kaprio, Jaakko; Lange, Anders; Koskenvuo, Markku; Jartti, Laura; Rönnemaa, Tapani; Hammar, Niklas

2007-01-01

Finland and Sweden are neighbouring countries with a substantially higher incidence and mortality from coronary heart disease (CHD) in Finland. Migration from Finland to Sweden has resulted in a population of about 187,000 Finnish immigrants, with a higher risk of CHD than Swedes. The aim of the present study was to analyse the prevalence of CHD in migrants to Sweden compared with co-twins remaining in Finland. The study population consisted of twin pairs of the Finnish Twin Cohort Study where at least one twin had lived one year or more in Sweden, including 1,534 subjects and 251 complete twin pairs discordant regarding residency in Sweden. Emigrant twins were compared with nonmigrant co-twins regarding prevalence of CHD in 1998. CHD prevalence was assessed by self-reported questionnaires validated using information from a clinical examination. Self-reported CHD showed a good correspondence with clinical diagnosis. Differences in social and behavioural risk factors for CHD among men were small but emigrants were more physically active than non-migrants. Female emigrants had less overweight and better education, but were more often working class than non-migrants. Intra-pair comparisons restricted to migration discordant pairs showed a tendency towards a reduced prevalence of CHD in the migrant co-twins (0.6; 0.3-1.4). In analyses of all subjects disregarding pair status, emigrants showed a reduced prevalence of CHD compared with subjects always living in Finland (0.6; 0.4-0.9). Emigration from Finland to Sweden may be associated with a reduced prevalence of CHD. The causes are most likely multifactorial and may involve changes in dietary habits, physical activity, psychosocial factors, and inflammation.

The Peruvian diaspora: portrait of a migratory process.

PubMed

Durand, Jorge

2010-01-01

Since the 1980s and especially the 1990s, Peru has become a nation of emigrants. Emigration has become massive over the past two decades, and the Peruvian populations of the United States, Japan, and Spain have tripled in less than a decade. A survey of households in five localities, three urban and two rural, in and around Lima helps to reveal the special character of this emigration. It tends to involve older and better-educated individuals than are typical of international migration and to target a wider variety of destinations. Moreover, it is a multiclass phenomenon. The economic, political, and social crisis brought about by a change in the economic model, two decades of terrorism, and a succession of failed democratic administrations has affected the society as a whole, and international migration seems to operate as an escape valve.

Psychoanalysis and the Emigration of Central and Eastern European Intellectuals.

PubMed

Erős, Ferenc

2016-12-01

One of the most important phenomena in the intellectual history of the 20th century was the exodus of the European mind, the emigration of persons, ideas, techniques, and institutions in the vast areas of social, human, and natural sciences, as well as in literature and the visual arts. Among these exiled intellectuals, psychoanalysts formed a special group. This paper examines the major lines of the emigration of psychoanalysts from the countries of issue to the countries of reception. It focuses, in particular on Hungarian analysts and analytic candidates who left their country of birth in two waves, first after the failure of revolutions in 1918/19 for Berlin, and then after 1938, to escape the Nazis. The paper comments on the existential situation of émigré psychoanalysts in light of Hannah Arendt's writings on refugees.

JPRS Report, West Europe

DTIC Science & Technology

1987-06-05

Economy Through 1989 (Jan Magnus Fahlstrom; DAGENS NYHETER, 9 Apr 87) 98 SOCIAL SWEDEN Lapps Weigh Emigration Following Chernobyl Devastation...after Chernobyl the Soviet state is a bogeyman for the rest of the world—in human terms, economically and in the area of envir- onmental technology...election year." 11798 , CS0: 3650/102 99 „«„■P»T SWEDEN SOCIAL LAPPS WEIGH EMIGRATION FOLLOWING CHERNOBYL DEVASTATION Stockholm DAGENS NYHETER

Migration Flow and Its Impact on Tuberculosis Notification in Portugal.

PubMed

Dias, Ana; Gaio, Rita; Sousa, Pedro; Gomes, Marta; Oliveira, Olena; Duarte, Raquel

2018-01-01

Tuberculosis notification in Portugal has decreased in the last few years. As a consequence of the economic crisis, emigration has increased and immigration has decreased. Immigrants are a risk group for tuberculosis. Most emigrants are 20-44 years old and belong to the age group most affected by tuberculosis. To describe the decrease in tuberculosis notification in Portugal over the last years from a demographical point of view. Mathematical analysis was performed to quantify the effect of the migration movements (separately and simultaneously) on tuberculosis notification in Portugal from 2008 to 2014. We calculated the estimated tuberculosis notification for each year during the period of study: 1) fixing immigration rate and tuberculosis rate in immigrants at 2008 values; 2) fixing emigration rate and tuberculosis rate in emigrants at 2008 values; 3) fixing both phenomenons at 2008 values. The differences between the observed and the estimated numbers were small (≤0.5 cases/100000 inhabitants). Impact of the migration movements on tuberculosis notification rate does not seem to be significant when analyzed for each phenomenon individually and simultaneously, by our model. This might mean that we have to concentrate our efforts in other risk factors for tuberculosis. Copyright © 2017 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

The role of local populations within a landscape context: Defining and classifying sources and sinks

USGS Publications Warehouse

Runge, J.P.; Runge, M.C.; Nichols, J.D.

2006-01-01

The interaction of local populations has been the focus of an increasing number of studies in the past 30 years. The study of source-sink dynamics has especially generated much interest. Many of the criteria used to distinguish sources and sinks incorporate the process of apparent survival (i.e., the combined probability of true survival and site fidelity) but not emigration. These criteria implicitly treat emigration as mortality, thus biasing the classification of sources and sinks in a manner that could lead to flawed habitat management. Some of the same criteria require rather restrictive assumptions about population equilibrium that, when violated, can also generate misleading inference. Here, we expand on a criterion (denoted ?contribution? or Cr) that incorporates successful emigration in differentiating sources and sinks and that makes no restrictive assumptions about dispersal or equilibrium processes in populations of interest. The metric Cr is rooted in the theory of matrix population models, yet it also contains clearly specified parameters that have been estimated in previous empirical research. We suggest that estimates of emigration are important for delineating sources and sinks and, more generally, for evaluating how local populations interact to generate overall system dynamics. This suggestion has direct implications for issues such as species conservation and habitat management.

Human Resources for Health Challenges in Nigeria and Nurse Migration.

PubMed

Salami, Bukola; Dada, Foluke O; Adelakun, Folake E

2016-05-01

The emigration of sub-Saharan African health professionals to developed Western nations is an aspect of increasing global mobility. This article focuses on the human resources for health challenges in Nigeria and the emigration of nurses from Nigeria as the country faces mounting human resources for health challenges. Human resources for health issues in Nigeria contribute to poor population health in the country, alongside threats from terrorism, infectious disease outbreaks, and political corruption. Health inequities within Nigeria mirror the geographical disparities in human resources for health distribution and are worsened by the emigration of Nigerian nurses to developed countries such as the United States and the United Kingdom. Nigerian nurses are motivated to emigrate to work in healthier work environments, improve their economic prospects, and advance their careers. Like other migrant African nurses, they experience barriers to integration, including racism and discrimination, in receiving countries. We explore the factors and processes that shape this migration. Given the forces of globalization, source countries and destination countries must implement policies to more responsibly manage migration of nurses. This can be done by implementing measures to retain nurses, promote the return migration of expatriate nurses, and ensure the integration of migrant nurses upon arrival in destination countries. © The Author(s) 2016.

Factors contributing to the brain drain in speech-language pathology: a New Zealand example.

PubMed

Tillard, Gina D A

2011-08-01

The aim of this research was to determine what attracts students to speech-language pathology (SLP), and the influence of intrinsic and extrinsic factors on two types of "brain drain" in SLP: emigration and career shift. Fifty undergraduate students and 13 recent graduates completed a questionnaire that tapped three main areas, level of student debt, intentions to emigrate, and career intentions. Ninety-seven per cent of respondents were female, with a median age of 25 years. Most SLP students and graduates had high levels of debt on graduation. Debt contributed to levels of worry and the ability to participate in education. However, debt alone did not influence career choice or long-term career planning. Over half of the respondents intended to leave New Zealand within 2 years of graduation, citing salary, travel, and training opportunities as factors. Incentives to remain in the profession included increased salary, more training opportunities, and student debt repayment. SLP students' career decisions were mainly influenced by interest in the profession. The conclusion was that three main factors need to be explored in an effort to increase the likelihood that SLPs remain in New Zealand: salary levels, increased training opportunities, and contributions to reduce student debt.

[The effects of manpower emigration on income distribution and consumption models in the Egyptian economy].

PubMed

Abdel Fadil, M

1985-01-01

This work analyzes the effects of emigration from Egypt on the distribution of income and the consumption model of the Egyptian economy. The increasing role of remittances as a principal source of household income has disturbed the old division of income among socioeconomic groups. It is difficult to estimate the volume of remittances with any precision because of the variety of ways in which they can be made. Official statistics tend to underestimate their value by ignoring black market transactions, remittances of merchandise, and other forms. An estimate was made of the value of remittances in 1980 taking account of wage levels of 5 different types of workers in the principal employing countries, their average propensities to save, and the employment structure of migrants by socioprofessional groups. The average educational level of emigrants appears to have declined somewhat between 1972-78. Average monthly income for emigrants was estimated to range from 792 Egyptian pounds for technical and professional workers to 252 for unskilled workers and the propensity to save was estimated to range from 40% for technical and scientific workers to 15% for unskilled workers. The total income remitted in 1980 in millions of Egyptian pounds was estimated at 912 for 240,000 technical and scienfific workers, 739 for 360,000 intermediate level workers, 415 for 300,000 artisans and workers, 60 for 60,000 chauffeurs, and 109 for 240,000 unskilled workers. Although remittances have elevated the per capita income of the low income groups, their impact has been diminished by severe inflationary pressures which have led to a decline in living levels and a less complete satisfaction of basic needs. Salary levels of construction workers were 7-9 times higher in Egyptian pounds in 1977 in 3 countries of immigration than in Egypt, while they were 7-10 times higher in 4 countries for university professors. Remittances are used by families receiving them for subsistence or investment; lower income groups are more likely to use a large proportion for support and to buy locally produced goods, while higher income groups tend to save more and to purchase a larger proportion of imported goods. 1 of the significant effects of remittances is to orient individual consumption toward luxury consumer goods, which in turn entails a progressive substitution of imported for local goods and a growing disparity between the consumption of those who succeed in migrating and those who don't. Remittances sent by low income emigrants for family support are the only mechanism with a stimulating effect on the demand for local goods of mediocre quality; all the other mechanisms stimulate the demand for high quality imported goods and services which have a negligible stimulating effect for the poorest segments of the population, rural or urban.

Regulation of VH Replacement by B Cell Receptor (BCR)-mediated Signaling in Human Immature B Cells

PubMed Central

Liu, Jing; Lange, Miles D.; Hong, Sang Yong; Xie, Wanqin; Xu, Kerui; Huang, Lin; Yu, Yangsheng; Ehrhardt, Götz R. A.; Zemlin, Michael; Burrows, Peter D.; Su, Kaihong; Carter, Robert H.; Zhang, Zhixin

2013-01-01

VH replacement provides a unique RAG-mediated recombination mechanism to edit non-functional IgH genes or IgH genes encoding self reactive B cell receptors (BCRs) and contributes to the diversification of antibody repertoire in mouse and human. Currently, it is not clear how VH replacement is regulated during early B lineage cell development. Here we show that crosslinking BCRs induces VH replacement in human EU12 μHC+ cells and in the newly emigrated immature B cells purified from peripheral blood of healthy donors or tonsillar samples. BCR signaling-induced VH replacement is dependent on the activation of Syk and Src kinases; but is inhibited by CD19 co-stimulation, presumably through activation of the PI3 kinase pathway. These results show for the first time that VH replacement is regulated by BCR-mediated signaling in human immature B cells, which can be modulated by physiological and pharmacological treatments. PMID:23630348

Stochastic differential equation model for linear growth birth and death processes with immigration and emigration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Granita, E-mail: granitafc@gmail.com; Bahar, A.

This paper discusses on linear birth and death with immigration and emigration (BIDE) process to stochastic differential equation (SDE) model. Forward Kolmogorov equation in continuous time Markov chain (CTMC) with a central-difference approximation was used to find Fokker-Planckequation corresponding to a diffusion process having the stochastic differential equation of BIDE process. The exact solution, mean and variance function of BIDE process was found.

[The Dutch emigration pattern around 1840 in the European perspective].

PubMed

Stokvis Prd

1980-01-01

"In 1850 and 1860 the Netherlands ranked eighth among twelve North-Western European nations that contributed to the transatlantic migration. The Dutch emigration pattern reflecting the agrarian crisis of the 1840's resembled the one of Hanover and Westphalia, be it that like in Scandinavia the ecclesiastical situation played a more important part. Besides the motivating forces, conditions such as information, organization, public and official reactions, and transportation are reviewed." (SUMMARY IN ENG) excerpt

Migrant Selection and the Health of U.S. Immigrants From the Former Soviet Union

PubMed Central

Elo, Irma T.

2012-01-01

Few prior studies have investigated the health of U.S. immigrants from the former Soviet Union (FSU). Utilizing data from the 2000 U.S. census and the 2000–2007 National Health Interview Survey (NIHS), we compare levels of disability of FSU immigrants with U.S.-born whites (ages 50–84). Our findings suggest an “epidemiologic paradox” in that FSU immigrants possess higher levels of education compared with U.S.-born whites, but report considerably higher disability with and without adjustment for education. Nonetheless, FSU immigrants report lower levels of smoking and heavy alcohol use compared with U.S.-born whites. We further investigate disability by period of arrival among FSU immigrants. Changes in Soviet emigration policies conceivably altered the level of health selectivity among émigrés. We find evidence that FSU immigrants who emigrated during a period when a permission to emigrate was hard to obtain (1970–1986) displayed less disability compared with those who emigrated when these restrictions were less stringent (1987–2000). Finally, we compare disability among Russian-born U.S. immigrants with that of those residing in Russia as a direct test of health selectivity. We find that Russian immigrants report lower levels of disability compared with Russians in Russia, suggesting that they are positively selected for health despite their poor health relative to U.S.-born whites. PMID:22421810

Temporal constraints on the potential role of fry odors as cues of past reproductive success for spawning lake trout

USGS Publications Warehouse

Buchinger, Tyler J.; Marsden, J. Ellen; Binder, Thomas R.; Huertas, Mar; Bussy, Ugo; Li, Ke; Hanson, James E.; Krueger, Charles C.; Li, Weiming; Johnson, Nicholas

2017-01-01

Deciding where to reproduce is a major challenge for most animals. Many select habitats based upon cues of successful reproduction by conspecifics, such as the presence of offspring from past reproductive events. For example, some fishes select spawning habitat following odors released by juveniles whose rearing habitat overlaps with spawning habitat. However, juveniles may emigrate before adults begin to search for spawning habitat; hence, the efficacy of juvenile cues could be constrained by degradation or dissipation rates. In lake trout (Salvelinus namaycush), odors deposited by the previous year's offspring have been hypothesized to guide adults to spawning reefs. However, in most extant populations, lake trout fry emigrate from spawning reefs during the spring and adults spawn during the fall. Therefore, we postulated that the role of fry odors in guiding habitat selection might be constrained by the time between fry emigration and adult spawning. Time course chemical, physiological, and behavioral assays indicated that the odors deposited by fry likely degrade or dissipate before adults select spawning habitats. Furthermore, fry feces did not attract wild lake trout to constructed spawning reefs in Lake Huron. Taken together, our results indicate fry odors are unlikely to act as cues for lake trout searching for spawning reefs in populations whose juveniles emigrate before the spawning season, and underscore the importance of environmental constraints on social cues.

Resolved and open issues in chromaffin cell development.

PubMed

Unsicker, Klaus; Huber, Katrin; Schober, Andreas; Kalcheim, Chaya

2013-01-01

Ten years of research within the DFG-funded Collaborative Research Grant SFB 488 at the University of Heidelberg have added many new facets to our understanding of chromaffin cell development. Glucocorticoid signaling is no longer the key for understanding the determination of the chromaffin phenotype, yet a novel role has been attributed to glucocorticoids: they are essential for the postnatal maintenance of adrenal and extra-adrenal chromaffin cells. Transcription factors, as, e.g. MASH1 and Phox2B, have similar, but also distinct functions in chromaffin and sympathetic neuronal development, and BMP-4 not only induces sympathoadrenal (SA) cells at the dorsal aorta and within the adrenal gland, but also promotes chromaffin cell maturation. Chromaffin cells and sympathetic neurons share a common progenitor in the dorsal neural tube (NT) in vivo, as revealed by single cell electroporations into the dorsal NT. Thus, specification of chromaffin cells is likely to occur after cell emigration either during migration or close to colonization of the target regions. Mechanisms underlying the specification of chromaffin cells vs. sympathetic neurons are currently being explored. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Expectations and reality: a case study of return migration from the United States to Southern Italy.

PubMed

Cerase, F P

1974-01-01

A summary of Italy's emigration flows shows that Southern Italy sent her people abroad in great number, and, at the same time, return migration to Italy has been characteristic of a minority, e.g., an estimated 3000 from the US alone, 1964-68. Italy's modernization proceeded unevenly, the South remaining agricultural and for the most part, economically backward. Any form of identification with Italy as a country did not affect the Southern peasant thus preparing his/her way to emigrate as soon as any opportunity presented itself. Due to all the conditions which facilitated emigration from Italy on an individualistic and nonideological basis and without an understanding of the economic forces pushing the emigrant out, and in view of the lack of understanding of how the New World economy of the US was constituted, it is no surprise that the return migration of some remained as much ad hoc and based solely on individual motivations as was the emigration. The 2 fundamental approaches to the concept of immigrant both start by considering the immigrant in his/her new situation. 1 approach views the immigrant's success in the new situation as dependent upon acquiring values and patterns of behavior which would resolve his/her problems in the new society. According to the other approach, in order to resolve the problems of his/her new situation the immigrant must become critically aware of the consequences of his/her actions. The 1st view of conceiving integration has been prevalent, particularly in the study of international migration. And, mass migration from Italy, from the emigrant's perspective, is connected to a repeatedly unsuccessful search for economic success and failure to reach prevailing cultural objectives. The act of emigration, of abandonment, may thus be seen as the resolution of the disparity between the means at the emigrant's disposal and the objectives he/she seeks. The great majority succeed but some fail, and if they have a home and family to return to, they begin to think of returning. Returned migrants interviewed experienced an abrupt passage from a rural to an urban and industrial world. Few of the immigrants whose background was in a fa rm occupation engaged in farming upon arrival in the US. The factor determining whether the immigrant surmounts the problems of the 1st phase of his/her experience is his/her work. If the work the immigrant has found makes him/her part of the production process, the money earned makes him/her part of the consumption process. And, this is the 1st turning point in the experience as an immigrant. A return of conservativism is given when the immigrant continues to consider his/her earnings and investments in terms of the traditional scheme appropriate to the home country. Return of innovation is the term given to those who were unwilling or unable to accept fully their expected position in the new society and tended to detach themselves, even to the point of return to the mother country. The consequences of returns to the native society are summarized. In sum, it appears that returned migrants cannot function as vehicles of social development.

Emigration dynamics in the Arab region. IOM / UNFPA workshop, 7-8 October 1996, Geneva, Switzerland.

PubMed

Appleyard, R

1996-01-01

This paper describes the four research monographs on emigration that were presented at the December 1995 Regional Workshop in the Arab Region. The workshop was an exchange of views and discussion of policy implications of emigration. Monographs were presented by Dr. Mayar Farrag on emigration in Egypt, Professor Nadji Safir on migration in the Maghreb, Dr. Setenay Shami on emigration dynamics in Jordan, and Dr. Lynn Evans on behalf of Dr. Ivy Papps on migration in Gulf Cooperation Council (GCC) countries. Dr. Farrag identified three periods of migration. During the mid-1960s to the mid-1970s, migrants were officially encouraged by Egypt to fill education positions. During the 1970s, many migrants left for the oil-producing countries on a temporary basis. Since the mid-1980s, the influences on Egyptian migration have been the economic recession and oil prices in the Gulf states, the completion of infrastructure projects in most Gulf states, and the replacement of foreign labor with nationals. Dr. Farrag recommended improving the migrants' skills in English and technology in order to maintain a dominant flow of temporary migrants to the Gulf region. Professor Safir reported that persons from the Maghreb region (Tunisia, Algeria, and Morocco) migrated to France before independence and subsequently to West Germany and the Benelux countries. Algeria had the highest migration potential, and Morocco had the highest migration. Morocco had established networks in destination countries, high population growth rates, and high unemployment. Maghreb countries are receiving migrants from the south. Professor Safir recommended regional integration. Dr. Shami separated step migration from stepwise migration, which complicates push-pull theories. Dr. Papps argued that use of foreign labor may not be the best option for development, and that sending countries should be more aware of skill needs in GCC countries.

Current employment characteristics and career intentions of Lithuanian dentists.

PubMed

Janulyte, Vilija; Aleksejuniene, Jolanta; Puriene, Alina; Peciuliene, Vytaute; Benzian, Habib

2014-12-20

The present survey explored the current employment profile and future career intentions of Lithuanian general dentists and specialists. A census sampling method was employed with data collected by means of a structured questionnaire that inquired about demographics, different employment-related aspects (practice type and location, working hours, perceived lack of patients, etc.), and future career intentions (intent to emigrate, to change profession, or the timing of retirement). The final response rate was 67.6% corresponding to 2,008 respondents. The majority of all dentists work full or part-time in the private dental sector, more than one third of them owns a private practice or rents a dental chair. A minority of dentists works in the public dental sector. According to the survey, 26.6% of general dentists and 39.2% of dental specialists works overtime (> 40 hours per week; P < 0.001) and practice in multiple clinics (1.4 ± 0.6 and 2.0 ± 1.2, respectively; P < 0.001). One third of general dentists (31.3%) and dental specialists (31.4%) stated to have a low number of patients (P > 0.05). The majority (68.9% of general dentists and 65.9% of dental specialists) plans to work after the retirement age (P > 0.05). Emigration as an option for their professional career is being considered by 10.8% of general dentists and 8.3% of dental specialists (P > 0.05). Working either full or part-time in private practices (OR = 4.3) and younger age (≤ 35 years; OR = 2.2) are the two strongest predictors for a perceived insufficient number of patients. One third of dentists in Lithuania work long hours and lack patients. Many dentists practice in multiple locations and plan to retire after the official retirement age. Some dentists and dental specialists plan to emigrate. The perceived shortcomings within the dental care system and workforce planning of dentists need to be addressed.

[Colombian migration to the Venezuelan agrarian sector: a binational context].

PubMed

Mora, J; Gomez, A

1980-01-01

The authors attempt to determine the reasons for the chronic national labor shortage in the Venezuelan agrarian sector and for the large-scale emigration of Colombians to work in Venezuelan agriculture. The income of agricultural wage earners and the conditions of labor force reproduction in Venezuela are discussed as factors contributing to the labor shortage. With reference to Colombia, the rapid growth of international commerce and the policy of limiting wages are suggested as factors which contribute to emigration

[The members of the exiled Hungarian school, mourning and renewal].

PubMed

Brabant, E

1988-01-01

A historical survey of the Hungarian psycho-analytical movement, followed by a description of the two successive waves of emigration. After some biographical details about three analysts who emigrated--Alice Balint, Michael Balint and Géza Roheim--exile is considered from the viewpoint of regretting the past and subsequent "renewal". Its effect is traced in the work of Balint and Roheim. Finally exile is seen as an ordeal creative of Freudian thought and as an experience common to all human beings.

[Pakistan: emigration in the Gulf and its effects on the home economy].

PubMed

Imdad, N

1985-01-01

Pakistani emigration since the early 1970s has been primarily directed toward the oil-rich Gulf states. Over 2 million Pakistanis, 10% of the adult male workforce, now live outside their home country, 3/4 of them in the Gulf states. The emigration has shortterm advantages for Pakistan, which has a high unemployment rate and few other exports. 2 government bureaus and over 300 recruiting agencies encourage Pakistani emigration to the Gulf, and because of the foreign exchange earnings generated, such emigration has become an important concern of the government. Emigration has a long history in Pakistan as part of the migratory movements of the Indian subcontinent in general. Emigration in the 1960s was prompted by mechanization of agriculture and disturbances of traditional agrarian labor arrangements brought on by the Green Revolution. Concentrations of lands among the successful middle-sized producers led to a rural proletariat and exodus towards the cities, where possibilities of employment were scarce. Regions of declining income around the new capital of Islamabad were the 1st to take advantage of new employment opportunities in the Gulf states. Pakistani migration to the Gulf countries is temporary for individual workers, who stay an average of 3-6 years, but the effect is of chain migration as returning workers are replaced by other family members. Workers are not accompanied by family members and have almost no contact with the local Arab populations. They send most of their earnings to their families in Pakistan. 3/4 are under 30 years old, most are of rural origin, and the majority are from the northern provinces. Although 70% are married, only 4% of migrants, the most highly qualified, are accompanied by their families. About 41% are unskilled workers and 42.6% are semiskilled or skilled manual workers. In 1981, the average annual salary repatriated by a Pakistani working in the Gulf was $3000. The Pakistani government has not defined a migration policy but has established rules and procedures to curtail clandestine departures. Most migrants use the services of licensed private employment agencies and very few use public channels. Because the migration is relatively new and few studies have been done, it is difficult to evaluate its effects on the local economy. 1 result is a severe local shortage of labor, especially in construction and transportation, which has promoted inflation and particularly affected the most impoverished classes. Remissions are now the most important source of Pakistan's foreign exchange earnings, but are not being invested in economic, industrial, or agricultural development, which has remained stagnant while 55% of the national budget is directed to defense. Most migrant earnings are invested in housing, marriages and dowries, and luxury imported consumer goods. In the current state of Pakistan's economy, migration is the sole means of socioeconomic advancement for the vast majority, but the future of the movement is uncertain.

Comparing population size estimators for plethodontid salamanders

USGS Publications Warehouse

Bailey, L.L.; Simons, T.R.; Pollock, K.H.

2004-01-01

Despite concern over amphibian declines, few studies estimate absolute abundances because of logistic and economic constraints and previously poor estimator performance. Two estimation approaches recommended for amphibian studies are mark-recapture and depletion (or removal) sampling. We compared abundance estimation via various mark-recapture and depletion methods, using data from a three-year study of terrestrial salamanders in Great Smoky Mountains National Park. Our results indicate that short-term closed-population, robust design, and depletion methods estimate surface population of salamanders (i.e., those near the surface and available for capture during a given sampling occasion). In longer duration studies, temporary emigration violates assumptions of both open- and closed-population mark-recapture estimation models. However, if the temporary emigration is completely random, these models should yield unbiased estimates of the total population (superpopulation) of salamanders in the sampled area. We recommend using Pollock's robust design in mark-recapture studies because of its flexibility to incorporate variation in capture probabilities and to estimate temporary emigration probabilities.

Behavioral thermoregulation by juvenile spring and fall chinook salmon, Oncorhynchus tshawytscha, during smoltification

USGS Publications Warehouse

Sauter, S.T.; Crawshaw, L.I.; Maule, A.G.

2001-01-01

Fall chinook salmon evolved to emigrate during the summer months. The shift in the temperature preference we observed in smolting fall chinook but not spring chinook salmon may reflect a phylogenetic adaptation to summer emigration by (1) providing directional orientation as fall chinook salmon move into the marine environment, (2) maintaining optimal gill function during emigration and seawater entry, and/or (3) resetting thermoregulatory set-points to support physiological homeostasis once smolted fish enter the marine environment. Phylogenetically determined temperature adaptations and responses to thermal stress may not protect fall chinook salmon from the recent higher summer water temperatures, altered annual thermal regimes, and degraded cold water refugia that result from hydropower regulation of the Columbia and Snake rivers. The long-term survival of fall chinook salmon will likely require restoration of normal annual thermographs and rigorous changes in land use practices to protect critical thermal refugia and control maximum summer water temperatures in reservoirs.

Host defense against systemic infection with Streptococcus pneumoniae is impaired in E-, P-, and E-/P-selectin-deficient mice.

PubMed Central

Munoz, F M; Hawkins, E P; Bullard, D C; Beaudet, A L; Kaplan, S L

1997-01-01

Endothelial selectins mediate rolling of leukocytes on endothelium, a crucial step for leukocyte firm adhesion and emigration into sites of tissue injury and infection. To characterize the role of the endothelial selectins during bacterial sepsis in vivo, Streptococcus pneumoniae (1-10 x 10(6) colony-forming units) was inoculated intraperitoneally into wild-type mice and mice with E-, P-, or E-/P-selectin deficiencies. Mice were followed 10 d for morbidity, survival, clearance of bacteremia, and leukocyte migration to the peritoneal cavity and organs 48 h after infection. All selectin-deficient mice showed a more pronounced morbidity, a significantly higher mortality associated with persistent bacteremia, and a higher bacterial load when compared with wild-type mice. These differences were most remarkable in the E-selectin-deficient mice, which showed the highest rate of mortality and bacteremia (P

Spanish youth is emigrating: A bibliometric approach to the media coverage.

PubMed

Selva, Clara; Recordà, Aniol

2018-01-01

Recent years have witnessed the emigration of young Spanish people searching for labor opportunities. A decade after the beginning of the worldwide economic crisis in 2007, the rapid deterioration of living conditions and lack of opportunities for personal development combined with the breakdown of professional expectations have led thousands of young people to emigrate from Spain, creating the so-called youth exodus. The press has paid recurrent attention to this phenomenon, often using eye-catching headlines such as 'Brain Drain'. Given the regular interest of the media in this phenomenon, the objective of this research is to analyze the media coverage of the drain of Spanish talent capital, or the emigration of young Spanish people seeking a better future, to create a distributive map that defines the characteristics and trends of this coverage. The analyzed corpus comprises 346 articles from eight Spanish and eleven international newspapers. The articles were coded based on descriptive variables (i.e., author, publication year, newspaper and language) and categorical variables (i.e., section, method, approach to the phenomenon, assessment of the phenomenon and overview of the phenomenon). The results indicate a significant increase in press coverage over the past few years and reveal associations between assessment of the phenomenon and year and between assessment of the phenomenon and section. As a result of this research, new investigative lines are unveiled regarding the social construction of the phenomenon in the media and the identity and individual construction of the 'truncated careers' of young Spanish people.

Bayesian Population Forecasting: Extending the Lee-Carter Method.

PubMed

Wiśniowski, Arkadiusz; Smith, Peter W F; Bijak, Jakub; Raymer, James; Forster, Jonathan J

2015-06-01

In this article, we develop a fully integrated and dynamic Bayesian approach to forecast populations by age and sex. The approach embeds the Lee-Carter type models for forecasting the age patterns, with associated measures of uncertainty, of fertility, mortality, immigration, and emigration within a cohort projection model. The methodology may be adapted to handle different data types and sources of information. To illustrate, we analyze time series data for the United Kingdom and forecast the components of population change to the year 2024. We also compare the results obtained from different forecast models for age-specific fertility, mortality, and migration. In doing so, we demonstrate the flexibility and advantages of adopting the Bayesian approach for population forecasting and highlight areas where this work could be extended.

The macrodynamics of international migration as a socio-cultural diffusion process. Part B: applications.

PubMed

Diamantides, N D

1992-12-01

"This study formulates a model of the macrodynamics of international migration using a differential equation to capture the push-pull forces that propel it. The model's architecture rests on the functioning of information feedback between settled friends and family at the destination and potential emigrants at the origin.... Two specific paradigms of diverse nature serve to demonstrate the model's tenets and pertinence, one being Greek emigration to the United States since 1820, and the other total out-migration from Cyprus since statehood (1946)." excerpt

Spatiotemporal expression dynamics of selectins govern the sequential extravasation of neutrophils and monocytes in the acute inflammatory response.

PubMed

Zuchtriegel, Gabriele; Uhl, Bernd; Hessenauer, Maximilian E T; Kurz, Angela R M; Rehberg, Markus; Lauber, Kirsten; Krombach, Fritz; Reichel, Christoph A

2015-04-01

Leukocyte recruitment to the site of inflammation is a key event in a variety of cardiovascular pathologies. Infiltrating neutrophils constitute the first line of defense that precedes a second wave of emigrating monocytes reinforcing the inflammatory reaction. The mechanisms initiating this sequential process remained largely obscure. Using advanced in vivo microscopy and in vitro/ex vivo techniques, we identified individual spatiotemporal expression patterns of selectins and their principal interaction partners on neutrophils, resident/inflammatory monocytes, and endothelial cells. Coordinating the intraluminal trafficking of neutrophils and inflammatory monocytes to common sites of extravasation, selectins assign different sites to these immune cells for their initial interactions with the microvascular endothelium. Whereas constitutively expressed leukocyte L-selectin/CD62L and endothelial P-selectin/CD62P together with CD44 and P-selectin glycoprotein ligand-1/CD162 initiate the emigration of neutrophils, de novo synthesis of endothelial E-selectin/CD62E launches the delayed secondary recruitment of inflammatory monocytes. In this context, P-selectin/CD62P and L-selectin/CD62L together with P-selectin glycoprotein ligand-1/CD162 and CD44 were found to regulate the flux of rolling neutrophils and inflammatory monocytes, whereas E-selectin/CD62E selectively adjusts the rolling velocity of inflammatory monocytes. Moreover, selectins and their interaction partners P-selectin glycoprotein ligand-1/CD162 and CD44 differentially control the intraluminal crawling behavior of neutrophils and inflammatory monocytes collectively enabling the sequential extravasation of these immune cells to inflamed tissue. Our findings provide novel insights into the mechanisms initiating the sequential infiltration of the perivascular tissue by neutrophils and monocytes in the acute inflammatory response and might thereby contribute to the development of targeted therapeutic strategies for prevention and treatment of cardiovascular diseases. © 2015 American Heart Association, Inc.

Immune reconstitution with two different rabbit polyclonal anti-thymocytes globulins.

PubMed

Bamoulid, Jamal; Crepin, Thomas; Gaiffe, Emilie; Laheurte, Caroline; Moulin, Bruno; Frimat, Luc; Rieu, Philippe; Mousson, Christiane; Durrbach, Antoine; Heng, Anne-Elisabeth; Rebibou, Jean-Michel; Saas, Philippe; Courivaud, Cécile; Ducloux, Didier

2017-12-01

Broad T cell depletion by polyclonal anti-thymocyte globulins (ATG) has been used for many years as a part of immunosuppressive treatment in transplantation. Currently, two different ATG are used in clinical practice, Thymoglobulin and Grafalon. Due to differences in the immunization source, these products contain different specificities and quantity of antibodies. These differences may have clinical consequences. We conducted a nested study in a large prospective multicentric cohort of kidney transplant to determine whether Grafalon-treated and Thymoglobulin-treated patients experience different lymphocyte reconstitution and clinical outcomes. 182 patients matched for age, gender, CMV status, CMV prophylaxis, number of previous transplantation, and maintenance immunosuppressive treatment were included (Thymoglobulin, [n=91]; Grafalon®, [n=91]). One-year post-transplant, recent thymic emigrants were significantly decreased (12±10% vs 21±12%; p<0.001) in Grafalon-treated patients. By contrast, T cell activation (CD38+DR+Ki67+) and senescence (CD8+CD57+CD28-) was increased in Thymoglobulin-treated patients. Compared to Grafalon, Thymoglobulin was not associated with a significantly different rate of acute rejection. CMV disease (p=0.013) was more frequent in Thymoglobulin-treated patients. Grafalon and Thymoglobulin seem to be equivalent to prevent acute rejection. CMV disease is more frequent in Thymoglobulin-treated patients. One year post-transplant immune profile profoundly differs according to the type of ATG. Copyright © 2017 Elsevier B.V. All rights reserved.

Defective B cell tolerance in adenosine deaminase deficiency is corrected by gene therapy

PubMed Central

Sauer, Aisha V.; Morbach, Henner; Brigida, Immacolata; Ng, Yen-Shing; Aiuti, Alessandro; Meffre, Eric

2012-01-01

Adenosine deaminase (ADA) gene defects are among the most common causes of SCID. Restoration of purine metabolism and immune functions can be achieved by enzyme replacement therapy, or more effectively by bone marrow transplant or HSC gene therapy (HSC-GT). However, autoimmune complications and autoantibody production, including anti-nuclear antibodies (ANAs), frequently occur in ADA-SCID patients after treatment. To assess whether ADA deficiency affects the establishment of B cell tolerance, we tested the reactivity of recombinant antibodies isolated from single B cells of ADA-SCID patients before and after HSC-GT. We found that before HSC-GT, new emigrant/transitional and mature naive B cells from ADA-SCID patients contained more autoreactive and ANA-expressing clones, indicative of defective central and peripheral B cell tolerance checkpoints. We further observed impaired B cell receptor (BCR) and TLR functions in B cells after ADA inhibition, which may underlie the defects in B cell tolerance. Strikingly, after HSC-GT, ADA-SCID patients displayed quasi-normal early B cell tolerance checkpoints, as evidenced by restored removal of developing autoreactive and ANA-expressing B cells. Hence, ADA plays an essential role in controlling autoreactive B cell counterselection by regulating BCR and TLR functions. PMID:22622038

The migratory impact of minimum wage legislation: Puerto Rico, 1970-1987.

PubMed

Santiago, C E

1993-01-01

"This study examines the impact of minimum wage setting on labor migration. A multiple time series framework is applied to monthly data for Puerto Rico from 1970-1987. The results show that net emigration from Puerto Rico to the United States fell in response to significant changes in the manner in which minimum wage policy was conducted, particularly after 1974. The extent of commuter type labor migration between Puerto Rico and the United States is influenced by minimum wage policy, with potentially important consequences for human capital investment and long-term standards of living." excerpt

Collecting lymphatic vessel permeability facilitates adipose tissue inflammation and distribution of antigen to lymph node-homing adipose tissue dendritic cells.

PubMed

Kuan, Emma L; Ivanov, Stoyan; Bridenbaugh, Eric A; Victora, Gabriel; Wang, Wei; Childs, Ed W; Platt, Andrew M; Jakubzick, Claudia V; Mason, Robert J; Gashev, Anatoliy A; Nussenzweig, Michel; Swartz, Melody A; Dustin, Michael L; Zawieja, David C; Randolph, Gwendalyn J

2015-06-01

Collecting lymphatic vessels (CLVs), surrounded by fat and endowed with contractile muscle and valves, transport lymph from tissues after it is absorbed into lymphatic capillaries. CLVs are not known to participate in immune responses. In this study, we observed that the inherent permeability of CLVs allowed broad distribution of lymph components within surrounding fat for uptake by adjacent macrophages and dendritic cells (DCs) that actively interacted with CLVs. Endocytosis of lymph-derived Ags by these cells supported recall T cell responses in the fat and also generated Ag-bearing DCs for emigration into adjacent lymph nodes (LNs). Enhanced recruitment of DCs to inflammation-reactive LNs significantly relied on adipose tissue DCs to maintain sufficient numbers of Ag-bearing DCs as the LN expanded. Thus, CLVs coordinate inflammation and immunity within adipose depots and foster the generation of an unexpected pool of APCs for Ag transport into the adjacent LN. Copyright © 2015 by The American Association of Immunologists, Inc.

[Why would doctors from Debrecen go abroad? Results of a questionnaire].

PubMed

Szekanecz, Zoltán; Tóth, Zoltán; Hamar, Attila; Lánczi, Levente

2017-09-01

Numerous beliefs have arisen in relation to the emigration of doctors. First of all, in most cases emigration has been attributed to, almost exclusively, low salaries. There are a number of non-financial issues that could possibly be more easily addressed. In order to get closer to these issues, we sent out a 37-item questionnaire to doctors, who originally graduated from the University of Debrecen. Altogether 82 of them sent back the questionnaire. The mean age at the time of emigration was 32 years. The most popular destination was the United States, however, many colleagues left for the US to do research, as well as clinical practice. Among the European countries, the most popular ones were Sweden, Germany, United Kingdom, Switzerland and Norway. The five most popular clinical specialties were general practice, internal medicine, anesthesiology/intensive care, laboratory/pathology and surgery. With respect to the planned duration of working abroad, at the time of emigration one-fourth of our colleagues planned very short (<2 years) stay. When we asked them now, 38% plans much longer, even indefinite stay. The most common reasons of emigration were also assessed. The most common one was the lack of career track, followed by low salary, quality of life, family issues and adventurousness. Interestingly, burnout and "gratuities" were at the end of the list. A mean 1.3 million HUF per month would make our colleagues satisfied but they think that a mean 486.000 HUF would be realistic and would keep most doctors within the country. As far as university education is concerned, our colleagues agreed that the basic medical knowledge of Hungarian doctors is excellent, but their practical skills are much worse. Although returning to Hungary would be unrealistic by most colleagues, low salaries are definitely not the most important or exclusive reason for leaving the country. These issues are rather complex, there are numerous non-financial issues, which could be addressed much easier by expressing a positive attitude. Orv Hetil. 2017; 158(37): 1458-1468.

Could Hypomanic Traits Explain Selective Migration? Verifying the Hypothesis by the Surveys on Sardinian Migrants

PubMed Central

MG, Carta; MF, Moro; V, Kovess; MV, Brasesco; KM, Bhat; MC, Angermeyer; HS, Akiskal

2012-01-01

Introduction: A recent survey put forward the hypothesis that the emigration that occurred from Sardinia from the 1960’s to the 1980’s, selected people with a hypomanic temperament. The paper aims to verify if the people who migrated from Sardinia in that period have shown a high risk of mood disorders in the surveys carried out in their host countries, and if the results are consistent with this hypothesis. Methods: This is systematic review. Results: In the 1970’s when examining the attitudes towards migration in Sardinian couples waiting to emigrate, Rudas found that the decision to emigrate was principally taken by males. Female showed lower self-esteem than male emigrants. A study on Sardinian immigrants in Argentina carried out in 2001-02, at the peak of the economic crisis, found a high risk of depressive disorders in women only. These results were opposite to the findings recorded ten years earlier in a survey on Sardinian immigrants in Paris, where the risk of Depressive Episode was higher in young men only. Discussion: Data point to a bipolar disorder risk for young (probably hypomanic) male migrants in competitive, challenging conditions; and a different kind of depressive episodes for women in trying economic conditions. The results of the survey on Sardinian migrants are partially in agreement with the hypothesis of a selective migration of people with a hypomanic temperament. Early motivations and self-esteem seem related to the ways mood disorders are expressed, and to the vulnerability to specific triggering situations in the host country. PMID:23248679

Could hypomanic traits explain selective migration? Verifying the hypothesis by the surveys on sardinian migrants.

PubMed

Giovanni, Carta Mauro; Francesca, Moro Maria; Viviane, Kovess; Brasesco, Maria Veronica; Bhat, Krishna M; Matthias, Angermeyer C; Akiskal, Hagop S

2012-01-01

A recent survey put forward the hypothesis that the emigration that occurred from Sardinia from the 1960's to the 1980's, selected people with a hypomanic temperament. The paper aims to verify if the people who migrated from Sardinia in that period have shown a high risk of mood disorders in the surveys carried out in their host countries, and if the results are consistent with this hypothesis. This is systematic review. In the 1970's when examining the attitudes towards migration in Sardinian couples waiting to emigrate, Rudas found that the decision to emigrate was principally taken by males. Female showed lower self-esteem than male emigrants. A study on Sardinian immigrants in Argentina carried out in 2001-02, at the peak of the economic crisis, found a high risk of depressive disorders in women only. These results were opposite to the findings recorded ten years earlier in a survey on Sardinian immigrants in Paris, where the risk of Depressive Episode was higher in young men only. Data point to a bipolar disorder risk for young (probably hypomanic) male migrants in competitive, challenging conditions; and a different kind of depressive episodes for women in trying economic conditions. The results of the survey on Sardinian migrants are partially in agreement with the hypothesis of a selective migration of people with a hypomanic temperament. Early motivations and self-esteem seem related to the ways mood disorders are expressed, and to the vulnerability to specific triggering situations in the host country.

Radiation-Driven Migration: The Case of Minamisoma City, Fukushima, Japan, after the Fukushima Nuclear Accident

PubMed Central

Zhang, Hui; Yan, Wanglin; Oba, Akihiro; Zhang, Wei

2014-01-01

The emigration of residents following the Fukushima nuclear accident has resulted in aging and depopulation problems in radiation-contaminated areas. The recovery of affected areas, and even those areas with low radioactive pollution levels, is still heavily affected by this problem. This slow recovery consequently affects immigration patterns. This review aims to present possible factors that have contributed to this dilemma. We first present an overview of the evacuation protocol that was administered in the study area following the Fukushima accident. We then analyze characteristics of the subsequent exodus by comparing population data for both before and after the accident. Based on the findings of existing literature, we identify three causes of emigration: (1) The health risks of living in a low radiation zone are still unknown; (2) The post-disaster psychological disturbance and distrust of government information promotes the emigration of evacuees; (3) an absence of economic vitality and of a leading industry renders the area less attractive to individuals residing outside of the city. Further research is needed on this issue, especially with respect to countermeasures for addressing this problem. PMID:25207491

Spatial econometric model of natural disaster impacts on human migration in vulnerable regions of Mexico.

PubMed

Saldaña-Zorrilla, Sergio O; Sandberg, Krister

2009-10-01

Mexico's vast human and environmental diversity offers an initial framework for comprehending some of the prevailing great disparities between rich and poor. Its socio-economic constructed vulnerability to climatic events serves to expand this understanding. Based on a spatial econometric model, this paper tests the contribution of natural disasters to stimulating the emigration process in vulnerable regions of Mexico. Besides coping and adaptive capacity, it assesses the effects of economic losses due to disasters as well as the adverse production and trade conditions of the 1990s on emigration rates in 2000 at the municipality level. Weather-related disasters were responsible for approximately 80 per cent of economic losses in Mexico between 1980 and 2005, mostly in the agricultural sector, which continues to dominate many parts of the country. It is dramatic that this sector generates around only four per cent of gross domestic product but provides a livelihood to about one-quarter of the national population. It is no wonder, therefore, that most emigration from this country arises in vulnerable rural areas.

On the composition of the preimmune repertoire of T cells specific for Peptide-major histocompatibility complex ligands.

PubMed

Jenkins, Marc K; Chu, H Hamlet; McLachlan, James B; Moon, James J

2010-01-01

Millions of T cells are produced in the thymus, each expressing a unique alpha/beta T cell receptor (TCR) capable of binding to a foreign peptide in the binding groove of a host major histocompatibility complex (MHC) molecule. T cell-mediated immunity to infection is due to the proliferation and differentiation of rare clones in the preimmune repertoire that by chance express TCRs specific for peptide-MHC (pMHC) ligands derived from the microorganism. Here we review recent findings that have altered our understanding of how the preimmune repertoire is established. Recent structural studies indicate that a germline-encoded tendency of TCRs to bind MHC molecules contributes to the MHC bias of T cell repertoires. It has also become clear that the preimmune repertoire contains functionally heterogeneous subsets including recent thymic emigrants, mature naive phenotype cells, memory phenotype cells, and natural regulatory T cells. In addition, sensitive new detection methods have revealed that the repertoire of naive phenotype T cells consists of distinct pMHC-specific populations that consistently vary in size in different individuals. The implications of these new findings for the clonal selection theory, self-tolerance, and immunodominance are discussed.

Tandem carrying, a new foraging strategy in ants: description, function, and adaptive significance relative to other described foraging strategies

NASA Astrophysics Data System (ADS)

Guénard, Benoit; Silverman, Jules

2011-08-01

An important aspect of social insect biology lies in the expression of collective foraging strategies developed to exploit food. In ants, four main types of foraging strategies are typically recognized based on the intensity of recruitment and the importance of chemical communication. Here, we describe a new type of foraging strategy, "tandem carrying", which is also one of the most simple recruitment strategies, observed in the Ponerinae species Pachycondyla chinensis. Within this strategy, workers are directly carried individually and then released on the food resource by a successful scout. We demonstrate that this recruitment is context dependent and based on the type of food discovered and can be quickly adjusted as food quality changes. We did not detect trail marking by tandem-carrying workers. We conclude by discussing the importance of tandem carrying in an evolutionary context relative to other modes of recruitment in foraging and nest emigration.

The use of specialty training to retain doctors in Malawi: A discrete choice experiment.

PubMed

Mandeville, Kate L; Ulaya, Godwin; Lagarde, Mylène; Muula, Adamson S; Dzowela, Titha; Hanson, Kara

2016-11-01

Emigration has contributed to a shortage of doctors in many sub-Saharan African countries. Specialty training is highly valued by doctors and a potential tool for retention. Yet not all types of training may be valued equally. In the first study to examine preferences for postgraduate training in depth, we carried out a discrete choice experiment as part of a cross-sectional survey of all Malawian doctors within seven years of graduation and not yet in specialty training. Over August 2012 to March 2013, 148 doctors took part out of 153 eligible in Malawi. Despite evidence that specialty training is highly sought after, Malawian junior doctors would not accept all types of training. Doctors preferred timely training outside of Malawi in core specialties (internal medicine, general surgery, paediatrics, obstetrics & gynaecology). Specialty preferences are particularly strong, with most junior doctors requiring nearly double their monthly salary to accept training all in Malawi and over six-fold to accept training in ophthalmology (representing a bundle of unpopular but priority specialties). In contrast, the location of work before training did not significantly influence most doctors' choices when guaranteed specialty training. Using a latent class model, we identified four subgroups of junior doctors with distinct preferences. Policy simulations showed that these preferences could be leveraged by policymakers to improve retention in exchange for guaranteed specialty training, however incentivising the uptake of training in priority specialties will only be effective in those with more flexible preferences. These results indicate that indiscriminate expansion of postgraduate training to slow emigration of doctors from sub-Saharan African countries may not be effective unless doctors' preferences are taken into account. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Postthymic maturation influences the CD8 T cell response to antigen.

PubMed

Makaroff, Lydia E; Hendricks, Deborah W; Niec, Rachel E; Fink, Pamela J

2009-03-24

Complete T cell development requires postthymic maturation, and we investigated the influence of this ontological period on the CD8 T cell response to infection by comparing responses of mature CD8 T cells with those of recent thymic emigrants (RTEs). When activated with a noninflammatory stimulus or a bacterial or viral pathogen, CD8 RTEs generated a lower proportion of cytokine-producing effector cells and long-lived memory precursors compared with their mature counterparts. Although peripheral T cell maturation is complete within several weeks after thymic egress, RTE-derived memory cells continued to express inappropriate levels of memory cell markers and display an altered pattern of cytokine production, even 8 weeks after infection. When rechallenged, RTE-derived memory cells generated secondary effector cells that were phenotypically and functionally equivalent to those generated by their mature counterparts. The defects at the effector and memory stages were not associated with differences in the expression of T cell receptor-, costimulation-, or activation-associated cell surface markers yet were associated with lower Ly6C expression levels at the effector stage. This work demonstrates that the stage of postthymic maturation influences cell fate decisions and cytokine profiles of stimulated CD8 T cells, with repercussions that are apparent long after cells have progressed from the RTE compartment.

[The migration crisis of the summer of 1994. Balance and perspectives of Cuban emigration flows: 1984-1996].

PubMed

Rodriguez Chavez, E

1996-01-01

"The article argues that the rafters crisis of 1994 and the resulting migration agreements between the United States and Cuba in 1994 and 1995 were a radical turn in policies and migration flows between the two countries. The article also describes the general evolution of Cuban migration flows towards the U.S. from the 1984 bilateral agreement up to 1996. As a context, it describes the structural elements of recent Cuban emigration and the place Cubans occupy in the general immigration from Latin America and the Caribbean." (EXCERPT)

A personality theory of U.S. migration geography.

PubMed

Stetzer, F C

1985-01-01

"Neoclassical models of migration fail to account adequately for individual differences in propensity to migrate, rates of emigration from states and cities, and the generally high rates of population circulation common in the United States. This article proposes that migration propensity is related to an individual's personality. Using the facts that personality traits are generationally regenerative, both through inheritance and culture, and that the United States was settled in a series of migration waves from east to west, this theory predicts a spatial structuring of emigration rates which closely correspond to actual rates for states and major cities." excerpt

Ecology of fall-migrating ducks in central Illinois: A radar perspective

NASA Astrophysics Data System (ADS)

O'Neal, Benjamin J.

Research from the last two decades has elucidated the importance of migration in the annual cycle of ducks, but many aspects of migration ecology remain poorly understood due to the difficulty of investigating movements that occur over large spatial scales, at substantial heights and at night. Weather surveillance radar (WSR) offers a unique tool for observing movements of birds aloft, but until now has been used primarily to address questions only relevant to broad taxonomic groups. Using thermal infrared imaging, portable radar, and natural history, I ground-truthed WSR echoes originating from a complex of wetlands in the central Illinois River valley to develop a technique for identifying and enumerating ducks as they emigrated from this important stopover area. With this technique, I quantified duck emigrations during 7 falls (1996, 1997, 2003, and 2005-2008). I used WSR-derived estimates of annual turnover in combination with aerial inventory estimates of duck use to estimate the average amount of time ducks spent at my study site during fall (stopover duration). The mean stopover duration estimate of 11 days (SD = 4 days) was much shorter than a historical estimate (28 days) that has been use for regional waterfowl conservation planning. I also regressed average annual stopover duration estimates against an index of annual foraging habitat quality and found a strong, positive relationship (r2 = 0.71), suggesting ducks assessed local habitat conditions and adjusted time spent at the site. Weather influences the timing of migration in many avian taxa, but this relationship is poorly understood for ducks. An evaluation of competing models including 15 years of data indicated following winds aloft, no precipitation, less cloud cover, decreasing temperatures, increasing barometric pressure and date best predicted emigration (R2 = 0.52). Based on this model, the odds of a duck emigration occurring when winds were following and precipitation was absent were 13.2 to 1.0 (95% CI 7.8--22.4). Finally, the notion that ducks rely on leading-lines of rivers for visual orientation during flight is a dominant paradigm in waterfowl science. I examined departure tracks of emigration events from my study site during 1995--2009 and found ducks had a significant SSE directional preference (152°; P < 0.05), which differed significantly in all years from the course of the Illinois River (220°; P ≤ 0.001). This pattern was markedly different than the river-oriented route described for ducks departing this site in the mid-20th century. Thus, leading lines appear to have been unimportant for orientation in the majority of duck emigration events from the major stopover area examined here.

T-cell suicide gene therapy prompts thymic renewal in adults after hematopoietic stem cell transplantation.

PubMed

Vago, Luca; Oliveira, Giacomo; Bondanza, Attilio; Noviello, Maddalena; Soldati, Corrado; Ghio, Domenico; Brigida, Immacolata; Greco, Raffaella; Lupo Stanghellini, Maria Teresa; Peccatori, Jacopo; Fracchia, Sergio; Del Fiacco, Matteo; Traversari, Catia; Aiuti, Alessandro; Del Maschio, Alessandro; Bordignon, Claudio; Ciceri, Fabio; Bonini, Chiara

2012-08-30

The genetic modification of T cells with a suicide gene grants a mechanism of control of adverse reactions, allowing safe infusion after partially incompatible hematopoietic stem cell transplantation (HSCT). In the TK007 clinical trial, 22 adults with hematologic malignancies experienced a rapid and sustained immune recovery after T cell-depleted HSCT and serial infusions of purified donor T cells expressing the HSV thymidine kinase suicide gene (TK+ cells). After a first wave of circulating TK+ cells, the majority of T cells supporting long-term immune reconstitution did not carry the suicide gene and displayed high numbers of naive lymphocytes, suggesting the thymus-dependent development of T cells, occurring only upon TK+ -cell engraftment. Accordingly, after the infusions, we documented an increase in circulating TCR excision circles and CD31+ recent thymic emigrants and a substantial expansion of the active thymic tissue as shown by chest tomography scans. Interestingly, a peak in the serum level of IL-7 was observed after each infusion of TK+ cells, anticipating the appearance of newly generated T cells. The results of the present study show that the infusion of genetically modified donor T cells after HSCT can drive the recovery of thymic activity in adults, leading to immune reconstitution.

Myeloid Wnt ligands are required for normal development of dermal lymphatic vasculature.

PubMed

Muley, Ajit; Odaka, Yoshi; Lewkowich, Ian P; Vemaraju, Shruti; Yamaguchi, Terry P; Shawber, Carrie; Dickie, Belinda H; Lang, Richard A

2017-01-01

Resident tissue myeloid cells play a role in many aspects of physiology including development of the vascular systems. In the blood vasculature, myeloid cells use VEGFC to promote angiogenesis and can use Wnt ligands to control vascular branching and to promote vascular regression. Here we show that myeloid cells also regulate development of the dermal lymphatic vasculature using Wnt ligands. Using myeloid-specific deletion of the WNT transporter Wntless we show that myeloid Wnt ligands are active at two distinct stages of development of the dermal lymphatics. As lymphatic progenitors are emigrating from the cardinal vein and intersomitic vessels, myeloid Wnt ligands regulate both their numbers and migration distance. Later in lymphatic development, myeloid Wnt ligands regulate proliferation of lymphatic endothelial cells (LEC) and thus control lymphatic vessel caliber. Myeloid-specific deletion of WNT co-receptor Lrp5 or Wnt5a gain-of-function also produce elevated caliber in dermal lymphatic capillaries. These data thus suggest that myeloid cells produce Wnt ligands to regulate lymphatic development and use Wnt pathway co-receptors to regulate the balance of Wnt ligand activity during the macrophage-LEC interaction.

Juvenile salmonid use of freshwater emergent wetlands in the floodplain and its implications for conservation management

USGS Publications Warehouse

Henning, Julie A.; Gresswell, Robert E.; Fleming, Ian A.

2006-01-01

A recent trend of enhancing freshwater emergent wetlands for waterfowl and other wildlife has raised concern about the effects of such measures on juvenile salmonids. We undertook this study to quantify the degree and extent of juvenile Pacific salmon Oncorhynchus spp. utilization of enhanced and unenhanced emergent wetlands within the floodplain of the lower Chehalis River, Washington, and to determine the fate of the salmon using them. Enhanced emergent wetlands contained water control structures that provided an outlet for fish emigration and a longer hydroperiod for rearing than unenhanced wetlands. Age-0 and age-1 coho salmon O. kisutch were the most common salmonid at all sites, enhanced wetlands having significantly higher age-1 abundance than unenhanced wetlands that were a similar distance from the main-stem river. Yearling coho salmon benefited from rearing in two enhanced wetland habitats, where their specific growth rate and minimum estimates of survival (1.43%/d by weight and 30%; 1.37%/d and 57%) were comparable to those in other side-channel rearing studies. Dissolved oxygen concentrations decreased in emergent wetlands throughout the season and approached the limits lethal to juvenile salmon by May or June each year. Emigration patterns suggested that age-0 and age-1 coho salmon emigrated as habitat conditions declined. This observation was further supported by the results of an experimental release of coho salmon. Survival of fish utilizing emergent wetlands was dependent on movement to the river before water quality decreased or stranding occurred from wetland desiccation. Thus, our results suggest that enhancing freshwater wetlands via water control structures can benefit juvenile salmonids, at least in the short term, by providing conditions for greater growth, survival, and emigration.

The role of emergent wetlands as potential rearing habitats for juvenile salmonids

USGS Publications Warehouse

Henning, Julie A.; Gresswell, Robert E.; Flemming, Ian A.

2006-01-01

A recent trend of enhancing freshwater emergent wetlands for waterfowl and other wildlife has raised concern about the effects of such measures on juvenile salmonids. We undertook this study to quantify the degree and extent of juvenile Pacific salmon Oncorhynchus spp. utilization of enhanced and unenhanced emergent wetlands within the floodplain of the lower Chehalis River, Washington, and to determine the fate of the salmon using them. Enhanced emergent wetlands contained water control structures that provided an outlet for fish emigration and a longer hydroperiod for rearing than unenhanced wetlands. Age-0 and age-1 coho salmon O. kisutch were the most common salmonid at all sites, enhanced wetlands having significantly higher age-1 abundance than unenhanced wetlands that were a similar distance from the main-stem river. Yearling coho salmon benefited from rearing in two enhanced wetland habitats, where their specific growth rate and minimum estimates of survival (1.43%/d by weight and 30%; 1.37%/d and 57%) were comparable to those in other side-channel rearing studies. Dissolved oxygen concentrations decreased in emergent wetlands throughout the season and approached the limits lethal to juvenile salmon by May or June each year. Emigration patterns suggested that age-0 and age-1 coho salmon emigrated as habitat conditions declined. This observation was further supported by the results of an experimental release of coho salmon. Survival of fish utilizing emergent wetlands was dependent on movement to the river before water quality decreased or stranding occurred from wetland desiccation. Thus, our results suggest that enhancing freshwater wetlands via water control structures can benefit juvenile salmonids, at least in the short term, by providing conditions for greater growth, survival, and emigration.

[Impact of people's social behavior on schistosomiasis transmission in the Three Gorges Reservoir area].

PubMed

Zhang, Hui-Juan; Zhu, Rong; Wu, Cheng-Guo; Guo, Jia-Gang

2007-06-01

To investigate the changes in natural ecology and social environment after the construction of the dam in the Three Gorges Reservoir area, and to understand the social behavior status and education backgrounds of the local residents, and to analyze the potential impact of these factors on schistosomiasis spreading. Data of nature and social economy after the construction of the dam in the Three Gorge area were collected, and a cross-sectional study with questionnaire survey on information including social demographic characteristics, people's production and life style, knowledge about schistosomiasis was conducted among natives, emigrations. After the construction of the dam, as the stream became slower, the water-level fluctuating zone on the bank of the reservoir was formed. The main source of drinking water and daily life activity are mainly depends on the river supplying (accounting about 68.7% and 75.8%, respectively); due to the needs of farming, washing cloths and vegetables, 45.6% of resident had a close contact with river water. People with away-from-home employment among emigrations were increased from 5.7% to 18.7%. The proportion of using hygienic lavatory was 88.6%. The main source of water for drinking and daily life among emigrations was tap water (85.4% and 87.0%). The residents had no awareness about the health hazard for schistosomiasis, with less health information The natural environment of reservoir areas and the life style are risk factors for the spread of schistosomiasis. The improved sanitation condition and the economy construction after the construction of the dam is propitious to keeping away from the introduction of schistosomiasis. However, people with away-from-home employment among emigrations are still at risk of schistosomiasis.

Partitioning Detectability Components in Populations Subject to Within-Season Temporary Emigration Using Binomial Mixture Models

PubMed Central

O’Donnell, Katherine M.; Thompson, Frank R.; Semlitsch, Raymond D.

2015-01-01

Detectability of individual animals is highly variable and nearly always < 1; imperfect detection must be accounted for to reliably estimate population sizes and trends. Hierarchical models can simultaneously estimate abundance and effective detection probability, but there are several different mechanisms that cause variation in detectability. Neglecting temporary emigration can lead to biased population estimates because availability and conditional detection probability are confounded. In this study, we extend previous hierarchical binomial mixture models to account for multiple sources of variation in detectability. The state process of the hierarchical model describes ecological mechanisms that generate spatial and temporal patterns in abundance, while the observation model accounts for the imperfect nature of counting individuals due to temporary emigration and false absences. We illustrate our model’s potential advantages, including the allowance of temporary emigration between sampling periods, with a case study of southern red-backed salamanders Plethodon serratus. We fit our model and a standard binomial mixture model to counts of terrestrial salamanders surveyed at 40 sites during 3–5 surveys each spring and fall 2010–2012. Our models generated similar parameter estimates to standard binomial mixture models. Aspect was the best predictor of salamander abundance in our case study; abundance increased as aspect became more northeasterly. Increased time-since-rainfall strongly decreased salamander surface activity (i.e. availability for sampling), while higher amounts of woody cover objects and rocks increased conditional detection probability (i.e. probability of capture, given an animal is exposed to sampling). By explicitly accounting for both components of detectability, we increased congruence between our statistical modeling and our ecological understanding of the system. We stress the importance of choosing survey locations and protocols that maximize species availability and conditional detection probability to increase population parameter estimate reliability. PMID:25775182

Preparing for export? Medical and nursing student migration intentions post-qualification in South Africa

PubMed Central

Reardon, Candice

2013-01-01

Abstract Background The migration of health professionals can have a profound impact on health systems around the globe. The International Organization for Migration's (IOM) Mobility of Health Professionals Research Project (MoHProf) aimed to improve knowledge about the migration of healthcare professionals and understand migration intentions and factors influencing the migration of medical and nursing students. Objectives The study aimed to determine the proportion of nursing and medical students who were intending to emigrate, their attitudes and beliefs about, and the factors influencing their decision to emigrate. Method This study was conducted at three medical schools and one nursing school in South Africa (n = 298) amongst 260 medical and 38 nursing students. One hundred and twenty-five students were in the final year of their studies and 143 were in their prefinal year. Thirty students did not indicate the year of their studies. Every student present on the day of data collection completed a questionnaire comprising psychometric and survey-based questions. Descriptive and inferential statistics were used to analyse the data. Results More than a third (37%) of the respondents intended to work or specialise abroad. The majority of medical (58.9%) and nursing (66.6%) students intended to leave SA within five years of completing their medical or nursing studies. The perception of poor working conditions within the health sector, such as long work hours, high patient loads, inadequate resources and occupational hazards, influenced medical students to consider emigrating from South Africa. Conclusion The high number of medical and nursing students intending to emigrate requires a reassessment of effectiveness of retention strategies for doctors and nurses in the South African healthcare system and actions to improve working conditions in the public healthcare sector.

Social effects of labour migration: the Colombia experience.

PubMed

Cely Martinez, J N

1989-06-01

Colombia has traditionally been classified as a net exporter of manpower. However, the US's restrictions on immigration and the economic crisis in Venezuela, Colombia's sister republic, have affected both the volume and composition of emigration. It could be initially concluded that despite domestic difficulties and external problems, favorable economic prospects explain the present reduced outflow of immigrants. On the basis of a sample survey of applications taken during the last 2 years, 94% of arrivals were classified as professionals and technicians; the remainder were administrative workers. This achievement (which contrasts with high levels of unemployment among Colombian professionals) reflects new technological innovations. It appears that while Colombia exports engineers, it imports engineering. Opinion surveys conducted among employers, migrants, and educational authorities show that costs are not fully compensated by the migrant's improved standard of living in the country of destination, even if he has sent remittances to his country of origin. Investments in education and training yield no returns to the country if the recipient emigrates. The advantages of emigration, identified in the same surveys, include 1) reduction in internal pressure on the labor market, 2) improvement in the incomes of those who do not emigrate, and 3) resolution of economic problems for migrants. The Social Economics Plan implemented by the current government indirectly affects migratory processes by focusing on: 1) eradication of poverty; 2) the National Rehabilitation Plan, by which regional growth is stimulated in poor and economically precarious districts; and 3) the Integral Rural Development Plan which aims to eradicate poverty and improve production and commercialization in small-holding areas. The author concludes that the effects of migration on social structures must be examined in depth.

Density-dependent natal dispersal patterns in a leopard population recovering from over-harvest.

PubMed

Fattebert, Julien; Balme, Guy; Dickerson, Tristan; Slotow, Rob; Hunter, Luke

2015-01-01

Natal dispersal enables population connectivity, gene flow and metapopulation dynamics. In polygynous mammals, dispersal is typically male-biased. Classically, the 'mate competition', 'resource competition' and 'resident fitness' hypotheses predict density-dependent dispersal patterns, while the 'inbreeding avoidance' hypothesis posits density-independent dispersal. In a leopard (Panthera pardus) population recovering from over-harvest, we investigated the effect of sex, population density and prey biomass, on age of natal dispersal, distance dispersed, probability of emigration and dispersal success. Over an 11-year period, we tracked 35 subadult leopards using VHF and GPS telemetry. Subadult leopards initiated dispersal at 13.6 ± 0.4 months. Age at commencement of dispersal was positively density-dependent. Although males (11.0 ± 2.5 km) generally dispersed further than females (2.7 ± 0.4 km), some males exhibited opportunistic philopatry when the population was below capacity. All 13 females were philopatric, while 12 of 22 males emigrated. Male dispersal distance and emigration probability followed a quadratic relationship with population density, whereas female dispersal distance was inversely density-dependent. Eight of 12 known-fate females and 5 of 12 known-fate male leopards were successful in settling. Dispersal success did not vary with population density, prey biomass, and for males, neither between dispersal strategies (philopatry vs. emigration). Females formed matrilineal kin clusters, supporting the resident fitness hypothesis. Conversely, mate competition appeared the main driver for male leopard dispersal. We demonstrate that dispersal patterns changed over time, i.e. as the leopard population density increased. We conclude that conservation interventions that facilitated local demographic recovery in the study area also restored dispersal patterns disrupted by unsustainable harvesting, and that this indirectly improved connectivity among leopard populations over a larger landscape.

Identifying key demographic parameters of a small island-associated population of Indo-Pacific bottlenose dolphins (Reunion, Indian Ocean).

PubMed

Dulau, Violaine; Estrade, Vanessa; Fayan, Jacques

2017-01-01

Photo-identification surveys of Indo-Pacific bottlenose dolphins were conducted from 2009 to 2014 off Reunion Island (55°E33'/21°S07'), in the Indian Ocean. Robust Design models were applied to produce the most reliable estimate of population abundance and survival rate, while accounting for temporary emigration from the survey area (west coast). The sampling scheme consisted of a five-month (June-October) sampling period in each year of the study. The overall population size at Reunion was estimated to be 72 individuals (SE = 6.17, 95%CI = 61-85), based on a random temporary emigration (γ") of 0.096 and a proportion of 0.70 (SE = 0.03) distinct individuals. The annual survival rate was 0.93 (±0.018 SE, 95%CI = 0.886-0.958) and was constant over time and between sexes. Models considering gender groups indicated different movement patterns between males and females. Males showed null or quasi-null temporary emigration (γ" = γ' < 0.01), while females showed a random temporary emigration (γ") of 0.10, suggesting that a small proportion of females was outside the survey area during each primary sampling period. Sex-specific temporary migration patterns were consistent with movement and residency patterns observed in other areas. The Robust Design approach provided an appropriate sampling scheme for deriving island-associated population parameters, while allowing to restrict survey effort both spatially (i.e. west coast only) and temporally (five months per year). Although abundance and survival were stable over the six years, the small population size of fewer than 100 individuals suggested that this population is highly vulnerable. Priority should be given to reducing any potential impact of human activity on the population and its habitat.

Terrestrial habitat selection and strong density-dependent mortality in recently metamorphosed amphibians.

PubMed

Patrick, David A; Harper, Elizabeth B; Hunter, Malcolm L; Calhoun, Aram J K

2008-09-01

To predict the effects of terrestrial habitat change on amphibian populations, we need to know how amphibians respond to habitat heterogeneity, and whether habitat choice remains consistent throughout the life-history cycle. We conducted four experiments to evaluate how the spatial distribution of juvenile wood frogs, Rana sylvatica (including both overall abundance and localized density), was influenced by habitat choice and habitat structure, and how this relationship changed with spatial scale and behavioral phase. The four experiments included (1) habitat manipulation on replicated 10-ha landscapes surrounding breeding pools; (2) short-term experiments with individual frogs emigrating through a manipulated landscape of 1 m wide hexagonal patches; and habitat manipulations in (3) small (4-m2); and (4) large (100-m2) enclosures with multiple individuals to compare behavior both during and following emigration. The spatial distribution of juvenile wood frogs following emigration resulted from differences in the scale at which juvenile amphibians responded to habitat heterogeneity during active vs. settled behavioral phases. During emigration, juvenile wood frogs responded to coarse-scale variation in habitat (selection between 2.2-ha forest treatments) but not to fine-scale variation. After settling, however, animals showed habitat selection at much smaller scales (2-4 m2). This resulted in high densities of animals in small patches of suitable habitat where they experienced rapid mortality. No evidence of density-dependent habitat selection was seen, with juveniles typically choosing to remain at extremely high densities in high-quality habitat, rather than occupying low-quality habitat. These experiments demonstrate how prediction of the terrestrial distribution of juvenile amphibians requires understanding of the complex behavioral responses to habitat heterogeneity. Understanding these patterns is important, given that human alterations to amphibian habitats may generate extremely high densities of animals, resulting in high density-dependent mortality.

Density-Dependent Natal Dispersal Patterns in a Leopard Population Recovering from Over-Harvest

PubMed Central

Fattebert, Julien; Balme, Guy; Dickerson, Tristan; Slotow, Rob; Hunter, Luke

2015-01-01

Natal dispersal enables population connectivity, gene flow and metapopulation dynamics. In polygynous mammals, dispersal is typically male-biased. Classically, the ‘mate competition’, ‘resource competition’ and ‘resident fitness’ hypotheses predict density-dependent dispersal patterns, while the ‘inbreeding avoidance’ hypothesis posits density-independent dispersal. In a leopard (Panthera pardus) population recovering from over-harvest, we investigated the effect of sex, population density and prey biomass, on age of natal dispersal, distance dispersed, probability of emigration and dispersal success. Over an 11-year period, we tracked 35 subadult leopards using VHF and GPS telemetry. Subadult leopards initiated dispersal at 13.6 ± 0.4 months. Age at commencement of dispersal was positively density-dependent. Although males (11.0 ± 2.5 km) generally dispersed further than females (2.7 ± 0.4 km), some males exhibited opportunistic philopatry when the population was below capacity. All 13 females were philopatric, while 12 of 22 males emigrated. Male dispersal distance and emigration probability followed a quadratic relationship with population density, whereas female dispersal distance was inversely density-dependent. Eight of 12 known-fate females and 5 of 12 known-fate male leopards were successful in settling. Dispersal success did not vary with population density, prey biomass, and for males, neither between dispersal strategies (philopatry vs. emigration). Females formed matrilineal kin clusters, supporting the resident fitness hypothesis. Conversely, mate competition appeared the main driver for male leopard dispersal. We demonstrate that dispersal patterns changed over time, i.e. as the leopard population density increased. We conclude that conservation interventions that facilitated local demographic recovery in the study area also restored dispersal patterns disrupted by unsustainable harvesting, and that this indirectly improved connectivity among leopard populations over a larger landscape. PMID:25875293

What’s bad in cancer is good in the embryo: Importance of EMT in neural crest development

PubMed Central

Kerosuo, Laura; Bronner-Fraser, Marianne

2012-01-01

Although the epithelial to mesenchymal transition (EMT) is famous for its role in cancer metastasis, it also is a normal developmental event in which epithelial cells are converted into migratory mesenchymal cells. A prime example of EMT during development occurs when neural crest (NC) cells emigrate from the neural tube thus providing an excellent model to study the principles of EMT in a nonmalignant environment. NC cells start life as neuroepithelial cells intermixed with precursors of the central nervous system. After EMT, they delaminate and begin migrating, often to distant sites in the embryo. While proliferating and maintaining multipotency and cell survival the transitioning neural crest cells lose apicobasal polarity and the basement membrane is broken down. This review discusses how these events are coordinated and regulated, by series of events involving signaling factors, gene regulatory interactions, as well as epigenetic and post-transcriptional modifications. Even though the series of events involved in NC EMT are well known, the sequence in which these steps take place remains a subject of debate, raising the intriguing possibility that, rather than being a single event, neural crest EMT may involve multiple parallel mechanisms. PMID:22430756

Maternal overweight and obesity are associated with increased risk of type 1 diabetes in offspring of parents without diabetes regardless of ethnicity.

PubMed

Hussen, Hozan I; Persson, Martina; Moradi, Tahereh

2015-07-01

The incidence of type 1 diabetes in children is increasing in Sweden, as is the prevalence of maternal overweight/obesity. Therefore, the aim of this study was to investigate if maternal overweight/obesity increases the risk of type 1 diabetes in offspring of parents with and without diabetes, and of different ethnicities. The study cohort comprised 1,263,358 children, born in Sweden between 1992 and 2004. Children were followed from birth until diagnosis of type 1 diabetes, emigration, death or end of follow-up in 2009, whichever occurred first. First trimester maternal BMI was calculated (kg/m(2)). Poisson regression was used to calculate incidence rate ratios (IRRs) with 95% CI for type 1 diabetes in the offspring. The risk of type 1 diabetes was increased in offspring of parents with any type of diabetes regardless of parental ethnicity. High first trimester maternal BMI was associated with increased risk of type 1 diabetes only in offspring of parents without diabetes (IRR 1.33 [95% CI 1.20, 1.48]). Increasing incidence of type 1 diabetes in children with non-diabetic parents may partly be explained by increasing prevalence of maternal overweight/obesity.

The ethnic composition of migration in the former Soviet Union.

PubMed

Robertson, L R

1996-02-01

"This paper examines the impact of the disintegration of the Soviet Union on migration patterns within the newly independent states. Data on migration between Russia and the other 14 former Soviet republics are analyzed to reveal the magnitude and ethnic composition of migration after independence and to examine the assumption that Russians will tend to return to Russia, whereas members of other titular groups will emigrate to their respective newly independent states. The data suggest that nationalization not only pushes non-titular groups to emigrate from the former Soviet republics, but also pulls titular groups to immigrate to the newly independent states from Russia." excerpt

Reconsidering residency: Characterization and conservation implications of complex migratory patterns of shortnose sturgeon (Acispenser brevirostrum)

USGS Publications Warehouse

Dionne, Phillip E.; Zydlewski, Gayle B.; Kinnison, Michael T.; Zydlewski, Joseph D.; Wippelhauser, Gail S.

2013-01-01

Efforts to conserve endangered species usually involve attempts to define and manage threats at the appropriate scale of population processes. In some species that scale is localized; in others, dispersal and migration link demic units within larger metapopulations. Current conservation strategies for endangered shortnose sturgeon (Acipenser brevirostrum) assume the species is river resident, with little to no movement between rivers. However we have found that shortnose sturgeon travel more than 130 km through coastal waters between the largest rivers in Maine. Indeed, acoustic telemetry shows that shortnose sturgeon enter six out of the seven acoustically monitored rivers we have monitored, with over 70% of tagged individuals undertaking coastal migrations between river systems. Four migration patterns were identified for shortnose sturgeon inhabiting the Penobscot River, Maine: river resident (28%), spring coastal emigrant (24%), fall coastal emigrant (33%), and summer coastal emigrant (15%). No shortnose sturgeon classified as maturing female exhibited a resident pattern, indicating differential migration. Traditional river-specific assessment and management of shortnose sturgeon could be better characterized using a broader metapopulation scale, at least in the Gulf of Maine, that accounts for diverse migratory strategies and the importance of migratory corridors as critical habitat.

Fatty-acid profiles of white muscle and liver in stream-maturing steelhead trout Oncorhynchus mykiss from early migration to kelt emigration

USGS Publications Warehouse

Penney, Zachary L.; Moffitt, Christine M.

2015-01-01

The profiles of specific fatty acids (FA) in white muscle and liver of fasting steelhead troutOncorhynchus mykiss were evaluated at three periods during their prespawning migration and at kelt emigration in the Snake–Columbia River of Washington, Oregon and Idaho, to improve the understanding of energy change. Twenty-seven FAs were identified; depletion of 10 of these was positively correlated in liver and white muscle of prespawning O. mykiss. To observe relative changes in FA content more accurately over sampling intervals, the lipid fraction of tissues was used to normalize the quantity of individual FA to an equivalent tissue wet mass. Saturated and monounsaturated FAs were depleted between upstream migration in September and kelt emigration in June, whereas polyunsaturated FAs were more conserved. Liver was depleted of FAs more rapidly than muscle. Three FAs were detected across all sampling intervals: 16:0, 18:1 and 22:6n3, which are probably structurally important to membranes. When structurally important FAs of O. mykiss are depleted to provide energy, physiological performance and survival may be affected.

Use of olfactory cues by newly metamorphosed wood frogs (Lithobates sylvaticus) during emigration

USGS Publications Warehouse

Zydlewski, Joseph D.; Popescu, Viorel D.; Brodie, Bekka S.; Hunter, Malcom L.

2012-01-01

Juvenile amphibians are capable of long-distance upland movements, yet cues used for orientation during upland movements are poorly understood. We used newly metamorphosed Wood Frogs (Lithobates sylvaticus) to investigate: (1) the existence of innate (i.e., inherited) directionality, and (2) the use of olfactory cues, specifically forested wetland and natal pond cues during emigration. In a circular arena experiment, animals with assumed innate directionality did not orient in the expected direction (suggested by previous studies) when deprived of visual and olfactory cues. This suggests that juvenile Wood Frogs most likely rely on proximate cues for orientation. Animals reared in semi-natural conditions (1500 l cattle tanks) showed a strong avoidance of forested wetland cues in two different experimental settings, although they had not been previously exposed to such cues. This finding is contrary to known habitat use by adult Wood Frogs during summer. Juvenile Wood Frogs were indifferent to the chemical signature of natal pond (cattle tank) water. Our findings suggest that management strategies for forest amphibians should consider key habitat features that potentially influence the orientation of juveniles during emigration movements, as well as adult behavior.

Part of a global workforce: migration of British-trained pharmacists.

PubMed

Hassell, Karen; Nichols, Liza; Noyce, Peter

2008-04-01

Many countries, including the UK, have identified a shortage of pharmacists, partly due to emigration. This study was undertaken to examine the extent and nature of migration taking place among British-qualified pharmacists. Mixed methods, including secondary analysis of quantitative data, qualitative research and a large self-completion survey of all British-registered pharmacists with an overseas address. Almost 11% of British-registered pharmacists reside overseas. Nearly three-quarters are British-trained and most are UK nationals. The US, Canada and Australia are the main destinations. The majority work as pharmacists in health services, but sizeable proportions are either retired, not working for other reasons or work in industry. Those who emigrate include those returning home, moving for career opportunities, for lifestyle reasons or as a 'spouse trailer'. For many the move abroad is a permanent one. Great Britain is both a source and destination country for migrating pharmacists. Emigration currently exceeds immigration. Pharmacists are not migrating to developing countries, so the profession may want to consider ways of contributing to the health care systems in developing countries which are the source of some of the immigrant pharmacists to Great Britain.

[Poles, the authors of doctor theses of the faculty of medicine in Strasburg].

PubMed

Gepner-Wozniewska, M; Pruszyńska, A

1996-01-01

Among Poles emigrating from Poland in XIX century (after November and January insurrection) there have been physicians and students of medicine - practising in insurgent troops - and young people, who after arrival in France started medical studies at the medical faculties of Paris, Montpellier, and Strasburg. In Strasburg between 1833 and 1870 there have been promoted 1440 doctors of medicine, including 15 Polish emigrants (three have been granted diplomas before coming to France) and two sons of emigrants. Generally all of them were subsidized by the French government and released from additional payments. At the university they were treated favourably and they were even taking advantage of some conveniences. From the archival materials of the Faculty of Medicine and dossiers of students - refugees from the Department Archives of Bas-Rhin in Strasburg, there was possible to reconstruct the fragments of their biographies, even with such details as notes of exems or outward appearance. In biographical notes there have been presented 17 authors of the doctor's theses defended in Strasburg between 1833 and 1870 (12 were granted the diplomas between 1853 and 1847, five others - between 1867 and 1870).

Isolation and culture of neural crest cells from embryonic murine neural tube.

PubMed

Pfaltzgraff, Elise R; Mundell, Nathan A; Labosky, Patricia A

2012-06-02

The embryonic neural crest (NC) is a multipotent progenitor population that originates at the dorsal aspect of the neural tube, undergoes an epithelial to mesenchymal transition (EMT) and migrates throughout the embryo, giving rise to diverse cell types. NC also has the unique ability to influence the differentiation and maturation of target organs. When explanted in vitro, NC progenitors undergo self-renewal, migrate and differentiate into a variety of tissue types including neurons, glia, smooth muscle cells, cartilage and bone. NC multipotency was first described from explants of the avian neural tube. In vitro isolation of NC cells facilitates the study of NC dynamics including proliferation, migration, and multipotency. Further work in the avian and rat systems demonstrated that explanted NC cells retain their NC potential when transplanted back into the embryo. Because these inherent cellular properties are preserved in explanted NC progenitors, the neural tube explant assay provides an attractive option for studying the NC in vitro. To attain a better understanding of the mammalian NC, many methods have been employed to isolate NC populations. NC-derived progenitors can be cultured from post-migratory locations in both the embryo and adult to study the dynamics of post-migratory NC progenitors, however isolation of NC progenitors as they emigrate from the neural tube provides optimal preservation of NC cell potential and migratory properties. Some protocols employ fluorescence activated cell sorting (FACS) to isolate a NC population enriched for particular progenitors. However, when starting with early stage embryos, cell numbers adequate for analyses are difficult to obtain with FACS, complicating the isolation of early NC populations from individual embryos. Here, we describe an approach that does not rely on FACS and results in an approximately 96% pure NC population based on a Wnt1-Cre activated lineage reporter. The method presented here is adapted from protocols optimized for the culture of rat NC. The advantages of this protocol compared to previous methods are that 1) the cells are not grown on a feeder layer, 2) FACS is not required to obtain a relatively pure NC population, 3) premigratory NC cells are isolated and 4) results are easily quantified. Furthermore, this protocol can be used for isolation of NC from any mutant mouse model, facilitating the study of NC characteristics with different genetic manipulations. The limitation of this approach is that the NC is removed from the context of the embryo, which is known to influence the survival, migration and differentiation of the NC.

Diagnosis and management of nocardiosis after bone marrow stem cell transplantation in adults: lack of lymphocyte recovery as a major contributing factor.

PubMed

Mansi, L; Daguindau, E; Saas, P; Pouthier, F; Ferrand, C; Dormoy, A; Patry, I; Garnache, F; Rohrlich, P-S; Deconinck, E; Larosa, F

2014-06-01

Hematopoietic cell transplantation (HCT) is a curative treatment for hematological malignancies. This therapeutic approach is associated with a profound immune deficiency and an increased rate of opportunistic infections. Nocardiosis is a rare bacterial infection occurring mainly in patients with deficient cell-mediated immunity, such as AIDS patients or transplant recipients. Diagnosis of nocardiosis can be challenging, as signs and symptoms are non-specific. Routine prophylaxis with trimethoprin/sulfamethoxazole (TMP/SMZ) does not prevent the risk of infection. Between May 2001 and December 2009, five cases of nocardiosis were diagnosed from the 366 allogeneic HCT recipients in our centre. Four patients developed a disseminated nocardiosis within the first year after HCT. The fifth patient presented a localized cutaneous nocardiosis. In disseminated cases, median total CD4+ T-cells were below 100 cells/μL. Naive CD4+ CD45RA+/RO- T-cells were almost undetectable. CD8(+) T-cells and NK cells were below the normal range and CD19+ B-cell reconstitution was completely deficient. In a localized case, we observed a lack of naive thymic emigrants CD4+ CD45RA+/RO- T-cells. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Years in Cologne.

PubMed

Rajewsky, Klaus

2013-01-01

This review describes the building and scientific activity of the Immunology Department at the Institute for Genetics in Cologne, cofounded by Max Delbrück in post-World War II Germany. The protagonist, a child of Russian emigrants, became interested in antibodies as a postdoc at the Pasteur Institute in Paris and a proponent of the antigen-bridge model of T-B cell collaboration during his early time in Cologne. He was challenged by the gap between cellular immunology and molecular genetics and profited from the advances of the latter as well as postwar economic growth in Germany. The Immunology Department became a place, and little universe in itself, where young scientists from all over the world came together to study cellular and molecular mechanisms of antibody formation. This included work on normal and malignant B cells in the human, particularly the origin of Hodgkin lymphoma, but the main focus was on B cell development and homeostasis, the germinal center reaction, and immunological memory, developing recombinase-assisted and conditional gene targeting in mice as a main technical tool.

Hypoxia promotes production of neural crest cells in the embryonic head.

PubMed

Scully, Deirdre; Keane, Eleanor; Batt, Emily; Karunakaran, Priyadarssini; Higgins, Debra F; Itasaki, Nobue

2016-05-15

Hypoxia is encountered in either pathological or physiological conditions, the latter of which is seen in amniote embryos prior to the commencement of a functional blood circulation. During the hypoxic stage, a large number of neural crest cells arise from the head neural tube by epithelial-to-mesenchymal transition (EMT). As EMT-like cancer dissemination can be promoted by hypoxia, we investigated whether hypoxia contributes to embryonic EMT. Using chick embryos, we show that the hypoxic cellular response, mediated by hypoxia-inducible factor (HIF)-1α, is required to produce a sufficient number of neural crest cells. Among the genes that are involved in neural crest cell development, some genes are more sensitive to hypoxia than others, demonstrating that the effect of hypoxia is gene specific. Once blood circulation becomes fully functional, the embryonic head no longer produces neural crest cells in vivo, despite the capability to do so in a hypoxia-mimicking condition in vitro, suggesting that the oxygen supply helps to stop emigration of neural crest cells in the head. These results highlight the importance of hypoxia in normal embryonic development. © 2016. Published by The Company of Biologists Ltd.

Q & A: Alexander Varshavsky.

PubMed

Varshavsky, Alexander

2003-07-01

Alexander Varshavsky is Smits Professor of Cell Biology at the California Institute of Technology. He moved to Caltech in 1992, after 15 years at the MIT's Department of Biology. He was born and educated in Russia, and was 30 at the time of his emigration to the U.S. in 1977. In Russia, and for a while at MIT, he studied the structure and replication of chromosomes. Over the last 24 years, the work of his laboratory focused on the ubiquitin system and closely related fields. He is a member of the U.S. National Academy of Sciences, and has received the Gairdner Award, the Lasker Award, the General Motors Sloan Prize, the Wolf Prize, the Horwitz Prize, and the Wilson Medal.

Coexistence of the social types: genetic population structure in the ant Formica exsecta.

PubMed

Seppä, Perttu; Gyllenstrand, Niclas; Corander, Jukka; Pamilo, Pekka

2004-11-01

The ant Formica exsecta has two types of colonies that exist in sympatry but usually as separate subpopulations: colonies with simple social organization and single queens (M type) or colonial networks with multiple queens (P type). We used both nuclear (DNA microsatellites) and mitochondrial markers to study the transition between the social types, and the contribution of males and females in gene flow within and between the types. Our results showed that the social types had different spatial genetic structures. The M subpopulations formed a fairly uniform population, whereas the P subpopulations were, on average, more differentiated from each other than from the nearby M subpopulations and could have been locally established from the M-type colonies, followed by philopatric behavior and restricted emigration of females. Thus, the relationship between the two social types resembles that of source (M type) and sink (P type) populations. The comparison of mitochondrial (phiST) and nuclear (FST) differentiation indicates that the dispersal rate of males is four to five times larger than that of females both among the P-type subpopulations and between the social types. Our results suggest that evolution toward complex social organization can have an important effect on genetic population structure through changes in dispersal behavior associated with different sociogenetic organizations.

Sip1 mediates an E-cadherin-to-N-cadherin switch during cranial neural crest EMT

PubMed Central

Rogers, Crystal D.; Saxena, Ankur

2013-01-01

The neural crest, an embryonic stem cell population, initially resides within the dorsal neural tube but subsequently undergoes an epithelial-to-mesenchymal transition (EMT) to commence migration. Although neural crest and cancer EMTs are morphologically similar, little is known regarding conservation of their underlying molecular mechanisms. We report that Sip1, which is involved in cancer EMT, plays a critical role in promoting the neural crest cell transition to a mesenchymal state. Sip1 transcripts are expressed in premigratory/migrating crest cells. After Sip1 loss, the neural crest specifier gene FoxD3 was abnormally retained in the dorsal neuroepithelium, whereas Sox10, which is normally required for emigration, was diminished. Subsequently, clumps of adherent neural crest cells remained adjacent to the neural tube and aberrantly expressed E-cadherin while lacking N-cadherin. These findings demonstrate two distinct phases of neural crest EMT, detachment and mesenchymalization, with the latter involving a novel requirement for Sip1 in regulation of cadherin expression during completion of neural crest EMT. PMID:24297751

The CD8+ memory T-cell state of readiness is actively maintained and reversible

PubMed Central

Allam, Atef; Conze, Dietrich B.; Giardino Torchia, Maria Letizia; Munitic, Ivana; Yagita, Hideo; Sowell, Ryan T.; Marzo, Amanda L.

2009-01-01

The ability of the adaptive immune system to respond rapidly and robustly upon repeated antigen exposure is known as immunologic memory, and it is thought that acquisition of memory T-cell function is an irreversible differentiation event. In this study, we report that many phenotypic and functional characteristics of antigen-specific CD8 memory T cells are lost when they are deprived of contact with dendritic cells. Under these circumstances, memory T cells reverted from G1 to the G0 cell-cycle state and responded to stimulation like naive T cells, as assessed by proliferation, dependence upon costimulation, and interferon-γ production, without losing cell surface markers associated with memory. The memory state was maintained by signaling via members of the tumor necrosis factor receptor superfamily, CD27 and 4-1BB. Foxo1, a transcription factor involved in T-cell quiescence, was reduced in memory cells, and stimulation of naive CD8 cells via CD27 caused Foxo1 to be phosphorylated and emigrate from the nucleus in a phosphatidylinositol-3 kinase–dependent manner. Consistent with these results, maintenance of G1 in vivo was compromised in antigen-specific memory T cells in vesicular stomatitis virus-infected CD27-deficient mice. Therefore, sustaining the functional phenotype of T memory cells requires active signaling and maintenance. PMID:19617575

Direct foreign investment: a migration push-factor?

PubMed

Sassen-koob, S

1984-01-01

Policymakers and analysts now recognize that US military activities abroad contribute to the creation of refugee flows into the US. Previously, immigration into the US was viewed as a result of inept and failed domestic policies in the countries of origin. Results show that recent immigrants to the US come from countries with neither the poorest nor the largest population growth rate in the less developed world. However, the sending countries received US direct foreign investment (DFI) in the 1970s, particularly labor intensive investment in export manufacturing. Significant levels and concentrations of DFI promote emigration through: 1) the incorporation of new segments of the population into wage labor and the associated disruption of traditional work structures, 2) the feminization of the new industrial work force and its impact on the work opportunities of men, and 3) the consolidation of objective and ideological links with the highly industrialized countries where most foreign capital originates. The data suggest an examination of the causes of emigration on a much more specific level than that of underdevelopment, poverty, and population growth. These facts carry immediate policy implications for US immigration organizations: 1) if US firms in export processing zones recruited workers from the pool of unemployed--mostly prime-age males--rather than expanding the labor supply by recruiting young women, thereby disrupting unwaged work structures, and 2) if these firms would desist from having high turnover rates among workers, then the migration impact of this type of development would be minimized.

Ongoing Voluntary Settlement and Independent Agency: Evidence from China

PubMed Central

Feng, Jing; Ren, Xiaopeng; Ma, Xinran

2017-01-01

Voluntary frontier settlement leads to independent agency. Since this type of research has not yet been implemented in ongoing voluntary settlement frontiers, we conducted several cultural tasks to investigate Shenzhen, known as China’s ongoing “South Frontier,” which is composed mostly of people that have emigrated from other Chinese provinces within the past 30 years. We hypothesized that residents of Shenzhen are more independent than those in other regions of Mainland China. As predicted, residents of Shenzhen scored higher than China inland residents in self-reported independent beliefs and scored lower in nepotism. The results indicate that, even in a short-term ongoing frontier, voluntary settlement is associated with independent agency. PMID:28798712

Health professionals moving to... and from Portugal.

PubMed

Ribeiro, Joana Sousa; Conceição, Claudia; Pereira, Joel; Leone, Cláudia; Mendonça, Pedro; Temido, Marta; Vieira, Carlota Pacheco; Dussault, Gilles

2014-02-01

The mobility of health professionals in the European Union is a phenomenon which policy-makers must take into account to provide the conditions to adjust for demand and supply of health services. This paper presents the case of Portugal, a country which at the same time imports and exports health workers. Since the early 1990s Portugal became a destination country receiving foreign health care professionals. This situation is now changing with the current economic situation as fewer immigrants come and more Portuguese emigrate. Foreigners coming to Portugal do so in part for similar reasons that bring Portuguese to want to emigrate, mainly the search for better work conditions and professional development opportunities. The emigration of Portuguese health professionals is also stimulated by the difficulty for recently graduated nurses, dentists and diagnostic and therapeutic technicians to find employment, low salaries in the public and private sectors, heavy workloads, remuneration not related to performance and poor career prospects. The paradoxes described in this study illustrate the consequences of the absence of a policy for the health professions. Strategies based on evidence, and on an integrated information system that captures the dynamic evolution of the workforce in health are not only necessary but also a good investment. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Visual Navigation during Colony Emigration by the Ant Temnothorax rugatulus

PubMed Central

Bowens, Sean R.; Glatt, Daniel P.; Pratt, Stephen C.

2013-01-01

Many ants rely on both visual cues and self-generated chemical signals for navigation, but their relative importance varies across species and context. We evaluated the roles of both modalities during colony emigration by Temnothorax rugatulus. Colonies were induced to move from an old nest in the center of an arena to a new nest at the arena edge. In the midst of the emigration the arena floor was rotated 60°around the old nest entrance, thus displacing any substrate-bound odor cues while leaving visual cues unchanged. This manipulation had no effect on orientation, suggesting little influence of substrate cues on navigation. When this rotation was accompanied by the blocking of most visual cues, the ants became highly disoriented, suggesting that they did not fall back on substrate cues even when deprived of visual information. Finally, when the substrate was left in place but the visual surround was rotated, the ants' subsequent headings were strongly rotated in the same direction, showing a clear role for visual navigation. Combined with earlier studies, these results suggest that chemical signals deposited by Temnothorax ants serve more for marking of familiar territory than for orientation. The ants instead navigate visually, showing the importance of this modality even for species with small eyes and coarse visual acuity. PMID:23671713

Determinants of emigration and their impact on survival during dispersal in fox and jackal populations

PubMed Central

Kapota, Dror; Dolev, Amit; Bino, Gilad; Yosha, Dotan; Guter, Amichai; King, Roni; Saltz, David

2016-01-01

Animals disperse in response to poor resource conditions as a strategy of escaping harsh competition and stress, but may also disperse under good resource conditions, as these provide better chances of surviving dispersal and gaining fitness benefits such as avoiding kin competition and inbreeding. Individual traits should mediate the effect of resources, yielding a complex condition-dependent dispersal response. We investigated how experimental food reductions in a food-rich environment around poultry-growing villages interact with individual-traits (age, gender, body-mass) in two sympatric canids, red foxes and golden jackals, to jointly affect emigration propensity and survival during dispersal. Sub-adult foxes emigrated more frequently from the food-rich habitat than from the pristine, food-limited habitat, while adult foxes showed the opposite trend. During dispersal, adults exhibited lower survival while sub-adults did not experience additional mortality costs. Although fox mortality rates increased in response to food reduction, dispersal remained unchanged, while jackals showed strong dispersal response in two of the three repetitions. Jackal survival under food reduction was lowest for the dispersing individuals. While resources are an important dispersal determinant, different age classes and species experience the same resource environment differently and consequently have different motivations, yielding different dispersal responses and consequences. PMID:27050564

The Banyan tree: overseas migrants from South Asia.

PubMed

Tinker, H

1979-10-01

The number of Indian emigrants throughout the years has made little or no population difference to the country. With the population of India, Pakistan, and Bangladesh totalling about 700 million in the mid 1970s, emigration is almost irrelevant. In 3 small nations, Mauritius, Fiji, and Guyana, Indians form the majority of the population. Present demographic trends point to the same majority in Trinidad. Indians also are an important group in Malaya, Singapore, and Ceylon, where they are more than 10% of the overall population. In other countries Indians form a small, minority population without political power. Almost all the overseas communities preserved the essential of the Hindu, Muslim, or Sikh religions which they took with them. In the Caribbean the Indian, or East Indian, has discarded his mother tongue after 3 or more generations in isolation. In South Africa only very old emigrants still speak their native tongue. Indian communities abroad often separate into Hindu and Muslim communities. British society uses the term "multi-racial" to describe the pluralistic cultures in its colonies, but British culture is not multiracial. The term has meaning only when applied to an urban area such as Singapore. In Singapore a multilingual policy is applied in order to make the multiracial ideal a reality.

Women in 19th Century Irish immigration.

PubMed

Jackson, P

1984-01-01

By the 1950s--100 years after the great famine of 1845-49-- 57% of emigrants from the 26 countries of Ireland were women. In the latter 1/2 of the 19th Century, increasing proportions of women emigrated, until they outnumbered men. For women it was more than a flight from poverty. It was also an escape from an increasingly patriarchal society, whose asymetrical development as a colony curtailed women's social space, even in their traditional role as wife and mother. The famine, which is the single greatest influence forcing emigration, undermined the social fabric of an agrarian society, hastening the process of agricultural transformation. The growth of a new class of Irish a British grazier landlords resulted in a situation of acute land scarcity, encouraging tendencies to cling to one's land holding without dividing it. This, combined with new inheritance practices, gave rise to widespread arranged marriages as a means of land consolidation, and the dowry system. The spontaneous marriage practices of famine days also were replaced by a postponement of marriage. These trends severely reduced the choices exerted by women. The absence of big industrialized cities, which might have absorbed displaced rural populations, removed available options, particularly for women. The system of land monopoly and inheritance revolving around male heads of households reinforced partriarchal relations, within a framework of rigid sexual norms, whose enforcement was easy because the church, which played an important role in the emergence of these values, was a major landowner in itself. The subordinated, invisible status of women in post-famine Ireland, and growing barriers to easy access to marriage partners, to waged employment and self-expression, all helped ensure the higher and higher emigration rates of women. The economic transformation of Irish agriculture accelerated the establishment of oppressive values and helped depreciate the position of women to a very low level. The exodus of women from post-famine Ireland represented a refusal to accept the servile role accorded them.

Higher mobility of butterflies than moths connected to habitat suitability and body size in a release experiment

PubMed Central

Kuussaari, Mikko; Saarinen, Matias; Korpela, Eeva-Liisa; Pöyry, Juha; Hyvönen, Terho

2014-01-01

Mobility is a key factor determining lepidopteran species responses to environmental change. However, direct multispecies comparisons of mobility are rare and empirical comparisons between butterflies and moths have not been previously conducted. Here, we compared mobility between butterflies and diurnal moths and studied species traits affecting butterfly mobility. We experimentally marked and released 2011 butterfly and 2367 moth individuals belonging to 32 and 28 species, respectively, in a 25 m × 25 m release area within an 11-ha, 8-year-old set-aside field. Distance moved and emigration rate from the release habitat were recorded by species. The release experiment produced directly comparable mobility data in 18 butterfly and 9 moth species with almost 500 individuals recaptured. Butterflies were found more mobile than geometroid moths in terms of both distance moved (mean 315 m vs. 63 m, respectively) and emigration rate (mean 54% vs. 17%, respectively). Release habitat suitability had a strong effect on emigration rate and distance moved, because butterflies tended to leave the set-aside, if it was not suitable for breeding. In addition, emigration rate and distance moved increased significantly with increasing body size. When phylogenetic relatedness among species was included in the analyses, the significant effect of body size disappeared, but habitat suitability remained significant for distance moved. The higher mobility of butterflies than geometroid moths can largely be explained by morphological differences, as butterflies are more robust fliers. The important role of release habitat suitability in butterfly mobility was expected, but seems not to have been empirically documented before. The observed positive correlation between butterfly size and mobility is in agreement with our previous findings on butterfly colonization speed in a long-term set-aside experiment and recent meta-analyses on butterfly mobility. PMID:25614794

A Robust Design Capture-Recapture Analysis of Abundance, Survival and Temporary Emigration of Three Odontocete Species in the Gulf of Corinth, Greece

PubMed Central

Bonizzoni, Silvia; Bearzi, Giovanni; Eddy, Lavinia; Gimenez, Olivier

2016-01-01

While the Mediterranean Sea has been designated as a Global Biodiversity Hotspot, assessments of cetacean population abundance are lacking for large portions of the region, particularly in the southern and eastern basins. The challenges and costs of obtaining the necessary data often result in absent or poor abundance information. We applied capture-recapture models to estimate abundance, survival and temporary emigration of odontocete populations within a 2,400 km2 semi-enclosed Mediterranean bay, the Gulf of Corinth. Boat surveys were conducted in 2011–2015 to collect photo-identification data on striped dolphins Stenella coeruleoalba, short-beaked common dolphins Delphinus delphis (always found together with striped dolphins in mixed groups) and common bottlenose dolphins Tursiops truncatus, totaling 1,873 h of tracking. After grading images for quality and marking distinctiveness, 23,995 high-quality photos were included in a striped and common dolphin catalog, and 2,472 in a bottlenose dolphin catalog. The proportions of striped and common dolphins were calculated from the photographic sample and used to scale capture-recapture estimates. Best-fitting robust design capture-recapture models denoted no temporary emigration between years for striped and common dolphins, and random temporary emigration for bottlenose dolphins, suggesting different residency patterns in agreement with previous studies. Average estimated abundance over the five years was 1,331 (95% CI 1,122–1,578) striped dolphins, 22 (16–32) common dolphins, 55 (36–84) “intermediate” animals (potential striped x common dolphin hybrids) and 38 (32–46) bottlenose dolphins. Apparent survival was constant for striped, common and intermediate dolphins (0.94, 95% CI 0.92–0.96) and year-dependent for bottlenose dolphins (an average of 0.85, 95% CI 0.76–0.95). Our work underlines the importance of long-term monitoring to contribute reliable baseline information that can help assess the conservation status of wildlife populations. PMID:27926926

Identifying key demographic parameters of a small island–associated population of Indo-Pacific bottlenose dolphins (Reunion, Indian Ocean)

PubMed Central

Estrade, Vanessa; Fayan, Jacques

2017-01-01

Photo-identification surveys of Indo-Pacific bottlenose dolphins were conducted from 2009 to 2014 off Reunion Island (55°E33’/21°S07’), in the Indian Ocean. Robust Design models were applied to produce the most reliable estimate of population abundance and survival rate, while accounting for temporary emigration from the survey area (west coast). The sampling scheme consisted of a five-month (June–October) sampling period in each year of the study. The overall population size at Reunion was estimated to be 72 individuals (SE = 6.17, 95%CI = 61–85), based on a random temporary emigration (γ”) of 0.096 and a proportion of 0.70 (SE = 0.03) distinct individuals. The annual survival rate was 0.93 (±0.018 SE, 95%CI = 0.886–0.958) and was constant over time and between sexes. Models considering gender groups indicated different movement patterns between males and females. Males showed null or quasi-null temporary emigration (γ” = γ’ < 0.01), while females showed a random temporary emigration (γ”) of 0.10, suggesting that a small proportion of females was outside the survey area during each primary sampling period. Sex-specific temporary migration patterns were consistent with movement and residency patterns observed in other areas. The Robust Design approach provided an appropriate sampling scheme for deriving island-associated population parameters, while allowing to restrict survey effort both spatially (i.e. west coast only) and temporally (five months per year). Although abundance and survival were stable over the six years, the small population size of fewer than 100 individuals suggested that this population is highly vulnerable. Priority should be given to reducing any potential impact of human activity on the population and its habitat. PMID:28640918

Nonacademic Attributes Predict Medical and Nursing Student Intentions to Emigrate or to Work Rurally: An Eight-Country Survey in Asia and Africa

PubMed Central

Silvestri, David M.; Blevins, Meridith; Wallston, Kenneth A.; Afzal, Arfan R.; Alam, Nazmul; Andrews, Ben; Derbew, Miliard; Kaur, Simran; Mipando, Mwapatsa; Mkony, Charles A.; Mwachaka, Philip M.; Ranjit, Nirju; Vermund, Sten H.

2017-01-01

We sought to identify independent, nonacademic predictors of medical and nursing student intent to migrate abroad or from rural to urban areas after graduation in low- and middle-income countries (LMIC). This was a cross-sectional survey of 3,199 first- and final-year medical and nursing students at 16 training institutions in eight LMIC. Questionnaires assessed demographics, career intentions, and preferences regarding selected career, location, and work-related attributes. Using principal component analysis, student preferences were reduced into four discrete categories of priorities: 1) work environment resources, 2) location livability, 3) altruistic job values, and 4) individualistic job values. Students' preferences were scored in each category. Using students' characteristics and priority scores, multivariable proportional odds models were used to derive independent predictors of intentions to emigrate for work outside the country, or to work in a rural area in their native country. Students prioritizing individualistic values more often planned international careers (adjusted odds ratio [aOR] = 1.44, 95% confidence interval [CI] = 1.16–1.78), whereas those prioritizing altruistic values preferred rural careers (aOR = 1.82, 95% CI = 1.50–2.21). Trainees prioritizing high-resource environments preferentially planned careers abroad (aOR = 1.38, 95% CI = 1.12–1.69) and were unlikely to seek rural work (aOR = 0.60, 95% CI = 0.49–0.73). Independent of their priorities, students with prolonged prior rural residence were unlikely to plan emigration (aOR = 0.67, 95% CI = 0.50–0.90) and were more likely to plan a rural career (aOR = 1.53, 95% CI = 1.16–2.03). We conclude that use of nonacademic attributes in medical and nursing admissions processes would likely increase retention in high-need rural areas and reduce emigration “brain drain” in LMIC. PMID:28719284

Physician migration at its roots: a study on the emigration preferences and plans among medical students in Romania.

PubMed

Suciu, Şoimita Mihaela; Popescu, Codruta Alina; Ciumageanu, Mugur Daniel; Buzoianu, Anca Dana

2017-01-19

Migration of healthcare workers is receiving increased attention worldwide. In Europe, the creation of a border-free labor market and its expansion with the EU enlargements of 2004, 2007, and 2013 endowed health professionals with the right to provide services and to relocate to another EU Member State. For the Romanian doctors, the EU-wide recognition of the medical degree obtained in Romania has created new opportunities, while inadequate working conditions and relatively low salaries pushed many of them to search for employment abroad. As there is considerable uncertainty about the magnitude of the Romanian physicians' exodus, we performed a survey to assess the emigration intention of future Romanian doctors. The study was conducted over three consecutive years: 2013, 2014, and 2015 at the University of Medicine and Pharmacy "Iuliu Hatieganu" Cluj-Napoca, Romania. The self-administrated questionnaire included 19 questions regarding students' emigration intentions. All the 957 license-degree students participated in the study. In this study, 84.7% of subjects planned on seeking employment abroad after graduation. A large number of the students who have participated in the study have already started preparing for emigration, 21.7% of those who wished to migrate had already performed at least one Erasmus mobility in their country of choice, 44.5% have been enrolled in a language course, and 42.7% have searched for jobs on the Internet. The majority of Romanian medical students considering migration see it as a serious alternative to the continuation of their professional training started in Romania. The findings of this study are upsetting and can impact both policy crafting and future research. Structural reforms in the healthcare provisions are needed in order to facilitate the retention of medical personnel. Romanian policy makers need to devise a comprehensive national health workforce plan to deal with physician migration.

A Closer Look at the Junior Doctor Crisis in the United Kingdom's National Health Services: Is Emigration Justifiable?

PubMed

Teo, Wendy Zi Wei

2018-07-01

This article attempts to tackle the ethically and morally troubling issue of emigration of physicians from the United Kingdom, and whether it can be justified. Unlike most research that has already been undertaken in this field, which looks at migration from developing countries to developed countries, this article takes an in-depth look at the migration of physicians between developed countries, in particular from the United Kingdom (UK) to other developed countries such as Canada, Australia, New Zealand, and the United States (US). This examination was written in response to a current and critical crisis in the National Health Service (NHS), where impending contract changes may bring about a potential exodus of junior doctors.

International migration and the propagation of HIV in sub-Saharan Africa.

PubMed

Docquier, F; Vasilakis, Ch; Tamfutu Munsi, D

2014-05-01

In this paper, we identify and quantify the role of international migration in the propagation of HIV across sub-Saharan African countries. We use panel data on bilateral migration flows and HIV prevalence rates covering 44 countries after 1990. Controlling for unobserved heterogeneity, reverse causality, reflection issues, incorrect treatment of country fixed effects and spatial autocorrelation, we find evidence of a highly robust emigration-induced propagation mechanism. On the contrary, immigration has no significant effect. Numerical experiments reveal that the long-run effect of emigration accounts for more than 4 percent of the number of HIV cases in 15 countries (and more than 20 percent in 6 countries). Copyright © 2014 Elsevier B.V. All rights reserved.

The uncertain connection: free trade and rural Mexican migration to the United States.

PubMed

Cornelius, W A; Martin, P L

1993-01-01

"Will a North American Free Trade Agreement (NAFTA) decrease Mexican migration to the United States, as the U.S. and Mexican governments assert, or increase migration beyond the movement that would otherwise occur, as NAFTA critics allege? This article argues that it is easy to overestimate the additional emigration from rural Mexico owing to NAFTA-related economic restructuring in Mexico. The available evidence suggests four major reasons why Mexican emigration may not increase massively, despite extensive restructuring and displacement from traditional agriculture....NAFTA-related economic displacement in Mexico may yield an initial wave of migration to test the U.S. labor market, but this migration should soon diminish if the jobs that these migrants seek shift to Mexico." excerpt

[Morpho-functional reaction of spleen natural killer cells and macrophages to melatonin administration to the animals kept on different illumination regimens].

PubMed

Shatskikh, O A; Luzikova, E M

2012-01-01

The aim this investigation was to study the changes in the numbers of spleen CD57+ and CD68+ cells (natural killer cells and macrophages respectively) after melatonin administration to the animals kept on different illumination regimens. The experimental animals were given melatonin in dose of 0.03 mg per day for 2 and 4 weeks under conditions of natural illumination or artificial darkening. Spleen paraffin sections were stained using immunohistochemical methods for detection of CD57+ and CD68+ cells. It was shown that long-term administration of melatonin under conditions of natural illumination had an immunosuppressive effect, that was manifested by the depopulation of the marginal zones, white pulp and all the zones of the red pulp, parenchyma loosening and denudation of the reticular stroma of the organ. However, long-term hormone administration under conditions of artificial darkening had an immunostimulatory effect as evidenced by the increased inflow of immunocompetent cells into the spleen, their migration from the white pulp into the marginal zones and emigration into peripheral blood flow, concomitant with the increase in the number of lymphoid nodules. The number of CD57+ and CD68+ cells was increased in splenic periarterial lymphoid sheaths and decreased in B-dependent zones of the organ.

Interleukin-32 induces the differentiation of monocytes into macrophage-like cells.

PubMed

Netea, Mihai G; Lewis, Eli C; Azam, Tania; Joosten, Leo A B; Jaekal, Jun; Bae, Su-Young; Dinarello, Charles A; Kim, Soo-Hyun

2008-03-04

After emigration from the bone marrow to the peripheral blood, monocytes enter tissues and differentiate into macrophages, the prototype scavenger of the immune system. By ingesting and killing microorganisms and removing cellular debris, macrophages also process antigens as a first step in mounting a specific immune response. IL-32 is a cytokine inducing proinflammatory cytokines and chemokines via p38-MAPK and NF-kappaB. In the present study, we demonstrate that IL-32 induces differentiation of human blood monocytes as well as THP-1 leukemic cells into macrophage-like cells with functional phagocytic activity for live bacteria. Muramyl dipepide (MDP), the ligand for the intracellular nuclear oligomerization domain (NOD) 2 receptor, has no effect on differentiation alone but augments the monocyte-to-macrophage differentiation by IL-32. Unexpectedly, IL-32 reversed GM-CSF/IL-4-induced dendritic cell differentiation to macrophage-like cells. Whereas the induction of TNFalpha, IL-1beta, and IL-6 by IL-32 is mediated by p38-MAPK, IL-32-induced monocyte-to-macrophage differentiation is mediated through nonapoptotic, caspase-3-dependent mechanisms. Thus, IL-32 not only contributes to host responses through the induction of proinflammatory cytokines but also directly affects specific immunity by differentiating monocytes into macrophage-like cells.

Isolation and Culture of Neural Crest Cells from Embryonic Murine Neural Tube

PubMed Central

Pfaltzgraff, Elise R.; Mundell, Nathan A.; Labosky, Patricia A.

2012-01-01

The embryonic neural crest (NC) is a multipotent progenitor population that originates at the dorsal aspect of the neural tube, undergoes an epithelial to mesenchymal transition (EMT) and migrates throughout the embryo, giving rise to diverse cell types 1-3. NC also has the unique ability to influence the differentiation and maturation of target organs4-6. When explanted in vitro, NC progenitors undergo self-renewal, migrate and differentiate into a variety of tissue types including neurons, glia, smooth muscle cells, cartilage and bone. NC multipotency was first described from explants of the avian neural tube7-9. In vitro isolation of NC cells facilitates the study of NC dynamics including proliferation, migration, and multipotency. Further work in the avian and rat systems demonstrated that explanted NC cells retain their NC potential when transplanted back into the embryo10-13. Because these inherent cellular properties are preserved in explanted NC progenitors, the neural tube explant assay provides an attractive option for studying the NC in vitro. To attain a better understanding of the mammalian NC, many methods have been employed to isolate NC populations. NC-derived progenitors can be cultured from post-migratory locations in both the embryo and adult to study the dynamics of post-migratory NC progenitors11,14-20, however isolation of NC progenitors as they emigrate from the neural tube provides optimal preservation of NC cell potential and migratory properties13,21,22. Some protocols employ fluorescence activated cell sorting (FACS) to isolate a NC population enriched for particular progenitors11,13,14,17. However, when starting with early stage embryos, cell numbers adequate for analyses are difficult to obtain with FACS, complicating the isolation of early NC populations from individual embryos. Here, we describe an approach that does not rely on FACS and results in an approximately 96% pure NC population based on a Wnt1-Cre activated lineage reporter23. The method presented here is adapted from protocols optimized for the culture of rat NC11,13. The advantages of this protocol compared to previous methods are that 1) the cells are not grown on a feeder layer, 2) FACS is not required to obtain a relatively pure NC population, 3) premigratory NC cells are isolated and 4) results are easily quantified. Furthermore, this protocol can be used for isolation of NC from any mutant mouse model, facilitating the study of NC characteristics with different genetic manipulations. The limitation of this approach is that the NC is removed from the context of the embryo, which is known to influence the survival, migration and differentiation of the NC2,24-28. PMID:22688801

Ghrelin promotes thymopoiesis during aging

PubMed Central

Dixit, Vishwa Deep; Yang, Hyunwon; Sun, Yuxiang; Weeraratna, Ashani T.; Youm, Yun-Hee; Smith, Roy G.; Taub, Dennis D.

2007-01-01

The decline in adaptive immunity, T lymphocyte output, and the contraction of the TCR repertoire with age is largely attributable to thymic involution. The loss of thymic function with age may be due to diminished numbers of progenitors and the loss of critical cytokines and hormones from the thymic microenvironment. We have previously demonstrated that the orexigenic hormone ghrelin is expressed by immune cells and regulates T cell activation and inflammation. Here we report that ghrelin and ghrelin receptor expression within the thymus diminished with progressive aging. Infusion of ghrelin into 14-month-old mice significantly improved the age-associated changes in thymic architecture and thymocyte numbers, increasing recent thymic emigrants and improving TCR diversity of peripheral T cell subsets. Ghrelin-induced thymopoiesis during aging was associated with enhanced early thymocyte progenitors and bone marrow–derived Lin–Sca1+cKit+ cells, while ghrelin- and growth hormone secretagogue receptor–deficient (GHS-R–deficient) mice displayed enhanced age-associated thymic involution. Leptin also enhanced thymopoiesis in aged but not young mice. Our findings demonstrate what we believe to be a novel role for ghrelin and its receptor in thymic biology and suggest a possible therapeutic benefit of harnessing this pathway in the reconstitution of thymic function in immunocompromised subjects. PMID:17823656

Macrophagic CD146 promotes foam cell formation and retention during atherosclerosis

PubMed Central

Luo, Yongting; Duan, Hongxia; Qian, Yining; Feng, Liqun; Wu, Zhenzhen; Wang, Fei; Feng, Jing; Yang, Dongling; Qin, Zhihai; Yan, Xiyun

2017-01-01

The persistence of cholesterol-engorged macrophages (foam cells) in the artery wall fuels the development of atherosclerosis. However, the mechanism that regulates the formation of macrophage foam cells and impedes their emigration out of inflamed plaques is still elusive. Here, we report that adhesion receptor CD146 controls the formation of macrophage foam cells and their retention within the plaque during atherosclerosis exacerbation. CD146 is expressed on the macrophages in human and mouse atheroma and can be upregulated by oxidized low-density lipoprotein (oxLDL). CD146 triggers macrophage activation by driving the internalization of scavenger receptor CD36 during lipid uptake. In response to oxLDL, macrophages show reduced migratory capacity toward chemokines CCL19 and CCL21; this capacity can be restored by blocking CD146. Genetic deletion of macrophagic CD146 or targeting of CD146 with an antibody result in much less complex plaques in high-fat diet-fed ApoE−/− mice by causing lipid-loaded macrophages to leave plaques. Collectively, our findings identify CD146 as a novel retention signal that traps macrophages within the artery wall, and a promising therapeutic target in atherosclerosis treatment. PMID:28084332

Seeking greener pastures? The relationship between career satisfaction and the intention to emigrate: a survey of Ghanaian physicians.

PubMed

Opoku, Samuel T; Apenteng, Bettye A

2014-09-01

A significant number of physicians from developing nations emigrate to developed nations in search of better career opportunities. In addition to crippling the health systems of developing nations, the emigration of physicians from sub-Saharan African (SSA) countries results in a loss of return on investment to these nations. The purpose of this study was to identify the relationship between career satisfaction and the intention of active Ghanaian physicians to leave the country within the next 5 years. This study was a cross-sectional correlational study using data from a survey of practicing physicians in Ghana. The primary independent variables examined were dimensions of career satisfaction, assessed using an abridged form of the Physician Work Life Survey. Data from the multivariate ordered logistic regression model indicated that physicians who were house officers or medical officers and those who reported dissatisfaction with their compensation were more likely to report that they were thinking about leaving Ghana within the next 5 years. Health policies aimed at increasing monetary compensation and providing junior physicians with the resources needed to excel in their careers may improve the retention of physicians in Ghana. © The Author 2014. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Radiological Diagnoses in the Context of Emigration: Infectious diseases.

PubMed

Stojkovic, Marija; Müller, Jan; Junghanss, Thomas; Weber, Tim Frederik

2018-02-01

 Globalization and emigration impact on the spectrum of diseases challenging health care systems. Medical practitioners have to particularly prepare for infectious diseases.  The database of a health care center specialized on tropical medicine was screened for patients with history of migration and one of the following diagnoses: Cystic echinococcosis, tuberculosis, schistosomiasis, visceral leishmaniosis, and neurocysticercosis. Representative casuistics were prepared from select case histories. Radiological pertinent knowledge was compiled based on literature search.  A small selection of frequently imported infectious diseases covers a considerable fraction of health care problems associated with migration. For cystic echinococcosis, schistosomiasis, and neurocysticercosis imaging is the most relevant diagnostic procedure defining also disease stages. Tuberculosis and visceral leishmaniosis are important differentials for malignant diseases.  Imaging plays a meaningful role in diagnosis, treatment stratification, and follow-up of imported infectious diseases. Radiological skills concerning these diseases are important for providing health care for patients in context of migration.   · Imaging plays a meaningful role in multidisciplinary care for imported infectious diseases.. · A small selection covers a considerable fraction of infectious diseases expected in context of migration.. · Stojkovic M, Müller J, Junghanss T et al. Radiological Diagnoses in the Context of Emigration: Infectious diseases. Fortschr Röntgenstr 2018; 190: 121 - 133. © Georg Thieme Verlag KG Stuttgart · New York.

Temporal variability of local abundance, sex ratio and activity in the Sardinian chalk hill blue butterfly

USGS Publications Warehouse

Casula, P.; Nichols, J.D.

2003-01-01

When capturing and marking of individuals is possible, the application of newly developed capture-recapture models can remove several sources of bias in the estimation of population parameters such as local abundance and sex ratio. For example, observation of distorted sex ratios in counts or captures can reflect either different abundances of the sexes or different sex-specific capture probabilities, and capture-recapture models can help distinguish between these two possibilities. Robust design models and a model selection procedure based on information-theoretic methods were applied to study the local population structure of the endemic Sardinian chalk hill blue butterfly, Polyommatus coridon gennargenti. Seasonal variations of abundance, plus daily and weather-related variations of active populations of males and females were investigated. Evidence was found of protandry and male pioneering of the breeding space. Temporary emigration probability, which describes the proportion of the population not exposed to capture (e.g. absent from the study area) during the sampling process, was estimated, differed between sexes, and was related to temperature, a factor known to influence animal activity. The correlation between temporary emigration and average daily temperature suggested interpreting temporary emigration as inactivity of animals. Robust design models were used successfully to provide a detailed description of the population structure and activity in this butterfly and are recommended for studies of local abundance and animal activity in the field.

Dispersal Timing: Emigration of Insects Living in Patchy Environments.

PubMed

Lakovic, Milica; Poethke, Hans-Joachim; Hovestadt, Thomas

2015-01-01

Dispersal is a life-history trait affecting dynamics and persistence of populations; it evolves under various known selective pressures. Theoretical studies on dispersal typically assume 'natal dispersal', where individuals emigrate right after birth. But emigration may also occur during a later moment within a reproductive season ('breeding dispersal'). For example, some female butterflies first deposit eggs in their natal patch before migrating to other site(s) to continue egg-laying there. How breeding compared to natal dispersal influences the evolution of dispersal has not been explored. To close this gap we used an individual-based simulation approach to analyze (i) the evolution of timing of breeding dispersal in annual organisms, (ii) its influence on dispersal (compared to natal dispersal). Furthermore, we tested (iii) its performance in direct evolutionary contest with individuals following a natal dispersal strategy. Our results show that evolution should typically result in lower dispersal under breeding dispersal, especially when costs of dispersal are low and population size is small. By distributing offspring evenly across two patches, breeding dispersal allows reducing direct sibling competition in the next generation whereas natal dispersal can only reduce trans-generational kin competition by producing highly dispersive offspring in each generation. The added benefit of breeding dispersal is most prominent in patches with small population sizes. Finally, the evolutionary contests show that a breeding dispersal strategy would universally out-compete natal dispersal.

[Career Satisfaction of Medical Residents in Portugal].

PubMed

Martins, Maria João; Laíns, Inês; Brochado, Bruno; Oliveira-Santos, Manuel; Teixeira, Pedro Pinto; Brandão, Mariana; Cerqueira, Rui João; Castro-Ferreira, Ricardo; Bernardes, Carlos; Menezes, Miguel Nobre; Baptista, Bernardo Soares; Ladeiras-Lopes, Ricardo; Rei, Mariana Cruz; Rosa, Gilberto Pires da; Martins, José Luís; Mendonça Sanches, Maria; Ferreira-Pinto, Manuel J; Rato, Margarida; Costa e Silva, Miguel; Policiano, Catarina; Beato, João; Barbosa-Breda, João; Torres, João Pimentel; Leal, Inês; Rosa, Sílvia Aguiar; Ribeiro, Bárbara Carvalho; Costa, Francisco Rego; Palmela, Carolina; Gonçalves, Tiago Cúrdia; Morais, Luis; Marques, Tiago Reis

2015-01-01

The satisfaction with the medical profession has been identified as an essential factor for the quality of care, the wellbeing of patients and the healthcare systems' stability. Recent studies have emphasized a growing discontent of physicians, mainly as a result of changes in labor relations. To assess the perception of Portuguese medical residents about: correspondence of residency with previous expectations; degree of satisfaction with the specialty, profession and place of training; reasons for dissatisfaction; opinion regarding clinical practice in Portugal and emigration intents. Cross-sectional study. Data collection was conducted through the "Satisfaction with Specialization Survey", created in an online platform, designed for this purpose, between May and August 2014. From a total population of 5788 medical residents, 804 (12.25 %) responses were obtained. From this sample, 77% of the responses were from residents in the first three years. Results showed that 90% of the residents are satisfied with their specialty, 85% with the medical profession and 86% with their place of training. Nevertheless, results showed a decrease in satisfaction over the final years of residency. The overall assessment of the clinical practice scenario in Portugal was negative and 65% of residents have plans to emigrate after completing their residency. Portuguese residents revealed high satisfaction levels regarding their profession. However, their views on Portuguese clinical practice and the results concerning the intent to emigrate highlight the need to take steps to reverse this scenario.

Inbreeding avoidance, patch isolation and matrix permeability influence dispersal and settlement choices by male agile antechinus in a fragmented landscape.

PubMed

Banks, Sam C; Lindenmayer, David B

2014-03-01

Animal dispersal is highly non-random and has important implications for the dynamics of populations in fragmented habitat. We identified interpatch dispersal events from genetic tagging, parentage analyses and assignment tests and modelled the factors associated with apparent emigration and post-dispersal settlement choices by individual male agile antechinus (Antechinus agilis, a marsupial carnivore of south-east Australian forests). Emigration decisions were best modelled with on data patch isolation and inbreeding risk. The choice of dispersal destination by males was influenced by inbreeding risk, female abundance, patch size, patch quality and matrix permeability (variation in land cover). Males were less likely to settle in patches without highly unrelated females. Our findings highlight the importance of individual-level dispersal data for understanding how multiple processes drive non-randomness in dispersal in modified landscapes. Fragmented landscapes present novel environmental, demographic and genetic contexts in which dispersal decisions are made, so the major factors affecting dispersal decisions in fragmented habitat may differ considerably from unfragmented landscapes. We show that the spatial scale of genetic neighbourhoods can be large in fragmented habitat, such that dispersing males can potentially settle in the presence of genetically similar females after moving considerable distances, thereby necessitating both a choice to emigrate and a choice of where to settle to avoid inbreeding. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

Finite metapopulation models with density-dependent migration and stochastic local dynamics

PubMed Central

Saether, B.-E.; Engen, S.; Lande, R.

1999-01-01

The effects of small density-dependent migration on the dynamics of a metapopulation are studied in a model with stochastic local dynamics. We use a diffusion approximation to study how changes in the migration rate and habitat occupancy affect the rates of local colonization and extinction. If the emigration rate increases or if the immigration rate decreases with local population size, a positive expected rate of change in habitat occupancy is found for a greater range of habitat occupancies than when the migration is density-independent. In contrast, the reverse patterns of density dependence in respective emigration and immigration reduce the range of habitat occupancies where the metapopulation will be viable. This occurs because density-dependent migration strongly influences both the establishment and rescue effects in the local dynamics of metapopulations.

The health implications of deportation policy.

PubMed

Morris, Juliana E; Palazuelos, Daniel

2015-05-01

The United States detains and deports over 400,000 people annually. This large-scale effort has important consequences for the health of affected individuals and communities. A growing body of research suggests that deportation increases stress and mental illness, economic deprivation, and individual exposure to violence, while also contributing to destabilization and crime at the community level. The challenges to reintegration experienced by deportees are additional push factors that increase their desire to re-emigrate. Furthermore, the related destabilization of local communities also contributes to the push, not just for deportees, but for all affected people in the region. This phenomenon has important implications for the long-term effectiveness of current U.S. deportation policies, which may be contributing to destabilization in home countries and thus potentiating further unauthorized emigration to the U.S.

Multistate modelling extended by behavioural rules: An application to migration.

PubMed

Klabunde, Anna; Zinn, Sabine; Willekens, Frans; Leuchter, Matthias

2017-10-01

We propose to extend demographic multistate models by adding a behavioural element: behavioural rules explain intentions and thus transitions. Our framework is inspired by the Theory of Planned Behaviour. We exemplify our approach with a model of migration from Senegal to France. Model parameters are determined using empirical data where available. Parameters for which no empirical correspondence exists are determined by calibration. Age- and period-specific migration rates are used for model validation. Our approach adds to the toolkit of demographic projection by allowing for shocks and social influence, which alter behaviour in non-linear ways, while sticking to the general framework of multistate modelling. Our simulations yield that higher income growth in Senegal leads to higher emigration rates in the medium term, while a decrease in fertility yields lower emigration rates.

[Career guidance for registered nurse in the UK].

PubMed

Simón Melchor, Lucía; Simón Melchor, Alba

2014-04-01

Cuts in temporary contracts has had big consequences for newly qualified nurses with regards to finding employment. This cut in contracts has resulted in a doubling in the rate of unemployment in this profession. In the past nurses emigrated to other countries for purposes like knowledge of the language or to extend their training and experience, however today the emigration has become the only way out for many professional nurses. The reputation of nurses in Spain is recognised internationally, with the UK being one of the countries with the largest demand for Spanish nurses. Due to the great amount of job opportunities that are emerging in the UK, nurses need help and guidance in their careers, and also nurses need training in areas such as Professional Body, developing a curriculum, facing an interview etc...

[Economic aspects of migration: remittances by migrant workers].

PubMed

Prskawetz, A

1995-01-01

"Worldwide annual remittances...by migrant workers to their home countries amount to some 70 billion U.S. dollars, exceeded by oil export earnings only.... The amount of remittances depends on the income of both the migrants and their family members.... Remittances meant for investment at home are determined by interest rates, foreign exchange regulations, exchange rates, monetary stability etc. in the immigration and emigration countries. Home remittances and saving habits of emigrants also depend on whether or not they expect to return to their home countries and the prospects of family reunification, all of which is directly linked to the (immigration) policy and economic conditions of both the countries of origin and residence." The factors influencing remittances flowing into and out of Austria are analyzed using data from the Austrian National Bank. (EXCERPT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hepler, K.R.; Hansen, P.A.; Bernard, D.R.

Five emigrating populations of Dolly Varden and cutthroat trout were intercepted in 1989-1991 during seaward migration to Prince William Sound following the Exxon Valdez oil spill; two into the spill area, three into non-spill areas. Study populations were comprised of tagged adults and subadults. Survival rates were estimated with log-linear models of capture histories of tagged fish. We used a two-stage simulation based on bootstrapping and Monte Carlo techniques to compare average survival rates in study populations that were and were not associated with spilled oil. Growth and survival rates were significantly lower in study populations associated with spilled oil.more » Results are consistent with the occurrence of a deleterious impact on growth and survival of emigrating species, although unable to be confirmed as results emanated from observation, not experiment.« less

CMV reactivation drives posttransplant T-cell reconstitution and results in defects in the underlying TCRβ repertoire

PubMed Central

Suessmuth, Yvonne; Mukherjee, Rithun; Watkins, Benjamin; Koura, Divya T.; Finstermeier, Knut; Desmarais, Cindy; Stempora, Linda; Horan, John T.; Langston, Amelia; Qayed, Muna; Khoury, Hanna J.; Grizzle, Audrey; Cheeseman, Jennifer A.; Conger, Jason A.; Robertson, Jennifer; Garrett, Aneesah; Kirk, Allan D.; Waller, Edmund K.; Blazar, Bruce R.; Mehta, Aneesh K.; Robins, Harlan S.

2015-01-01

Although cytomegalovirus (CMV) reactivation has long been implicated in posttransplant immune dysfunction, the molecular mechanisms that drive this phenomenon remain undetermined. To address this, we combined multiparameter flow cytometric analysis and T-cell subpopulation sorting with high-throughput sequencing of the T-cell repertoire, to produce a thorough evaluation of the impact of CMV reactivation on T-cell reconstitution after unrelated-donor hematopoietic stem cell transplant. We observed that CMV reactivation drove a >50-fold specific expansion of Granzyme Bhigh/CD28low/CD57high/CD8+ effector memory T cells (Tem) and resulted in a linked contraction of all naive T cells, including CD31+/CD4+ putative thymic emigrants. T-cell receptor β (TCRβ) deep sequencing revealed a striking contraction of CD8+ Tem diversity due to CMV-specific clonal expansions in reactivating patients. In addition to querying the topography of the expanding CMV-specific T-cell clones, deep sequencing allowed us, for the first time, to exhaustively evaluate the underlying TCR repertoire. Our results reveal new evidence for significant defects in the underlying CD8 Tem TCR repertoire in patients who reactivate CMV, providing the first molecular evidence that, in addition to driving expansion of virus-specific cells, CMV reactivation has a detrimental impact on the integrity and heterogeneity of the rest of the T-cell repertoire. This trial was registered at www.clinicaltrials.gov as #NCT01012492. PMID:25852054

IL-15 induces CD4 effector memory T cell production and tissue emigration in nonhuman primates.

PubMed

Picker, Louis J; Reed-Inderbitzin, Edward F; Hagen, Shoko I; Edgar, John B; Hansen, Scott G; Legasse, Alfred; Planer, Shannon; Piatak, Michael; Lifson, Jeffrey D; Maino, Vernon C; Axthelm, Michael K; Villinger, Francois

2006-06-01

HIV infection selectively targets CD4+ effector memory T (T EM) cells, resulting in dramatic depletion of CD4+ T cells in mucosal effector sites in early infection. Regeneration of the T EM cell compartment is slow and incomplete, even when viral replication is controlled by antiretroviral therapy (ART). Here, we demonstrate that IL-15 dramatically increases in vivo proliferation of rhesus macaque (RM) CD4+ and CD8+ T EM cells with little effect on the naive or central memory T (T CM) cell subsets, a response pattern that is quite distinct from that of either IL-2 or IL-7. T EM cells produced in response to IL-15 did not accumulate in blood. Rather, 5-bromo-2'-deoxyuridine (BrdU) labeling studies suggest that many of these cells rapidly disperse to extralymphoid effector sites, where they manifest (slow) decay kinetics indistinguishable from that of untreated controls. In RMs with uncontrolled SIV infection and highly activated immune systems, IL-15 did not significantly increase CD4+ T EM cell proliferation, but with virologic control and concomitant reduction in immune activation by ART, IL-15 responsiveness was again observed. These data suggest that therapeutic use of IL-15 in the setting of ART might facilitate specific restoration of the CD4 + T cell compartment that is the primary target of HIV with less risk of exhausting precursor T cell compartments or generating potentially deleterious regulatory subsets.

IL-15 induces CD4+ effector memory T cell production and tissue emigration in nonhuman primates

PubMed Central

Picker, Louis J.; Reed-Inderbitzin, Edward F.; Hagen, Shoko I.; Edgar, John B.; Hansen, Scott G.; Legasse, Alfred; Planer, Shannon; Piatak, Michael; Lifson, Jeffrey D.; Maino, Vernon C.; Axthelm, Michael K.; Villinger, Francois

2006-01-01

HIV infection selectively targets CD4+ effector memory T (TEM) cells, resulting in dramatic depletion of CD4+ T cells in mucosal effector sites in early infection. Regeneration of the TEM cell compartment is slow and incomplete, even when viral replication is controlled by antiretroviral therapy (ART). Here, we demonstrate that IL-15 dramatically increases in vivo proliferation of rhesus macaque (RM) CD4+ and CD8+ TEM cells with little effect on the naive or central memory T (TCM) cell subsets, a response pattern that is quite distinct from that of either IL-2 or IL-7. TEM cells produced in response to IL-15 did not accumulate in blood. Rather, 5-bromo-2′-deoxyuridine (BrdU) labeling studies suggest that many of these cells rapidly disperse to extralymphoid effector sites, where they manifest (slow) decay kinetics indistinguishable from that of untreated controls. In RMs with uncontrolled SIV infection and highly activated immune systems, IL-15 did not significantly increase CD4+ TEM cell proliferation, but with virologic control and concomitant reduction in immune activation by ART, IL-15 responsiveness was again observed. These data suggest that therapeutic use of IL-15 in the setting of ART might facilitate specific restoration of the CD4+ T cell compartment that is the primary target of HIV with less risk of exhausting precursor T cell compartments or generating potentially deleterious regulatory subsets. PMID:16691294

Elevated CXCL1 expression in gp130-deficient endothelial cells impairs neutrophil migration in mice

PubMed Central

Yao, Longbiao; Yago, Tadayuki; Shao, Bojing; Liu, Zhenghui; Silasi-Mansat, Robert; Setiadi, Hendra; Lupu, Florea

2013-01-01

Neutrophils emigrate from venules to sites of infection or injury in response to chemotactic gradients. How these gradients form is not well understood. Some IL-6 family cytokines stimulate endothelial cells to express adhesion molecules and chemokines that recruit leukocytes. Receptors for these cytokines share the signaling subunit gp130. We studied knockout mice lacking gp130 in endothelial cells. Unexpectedly, gp130-deficient endothelial cells constitutively expressed more CXCL1 in vivo and in vitro, and even more upon stimulation with tumor necrosis factor-α. Mobilization of this increased CXCL1 from intracellular stores to the venular surface triggered β2 integrin–dependent arrest of neutrophils rolling on selectins but impaired intraluminal crawling and transendothelial migration. Superfusing CXCL1 over venules promoted neutrophil migration only after intravenously injecting mAb to CXCL1 to diminish its intravascular function or heparinase to release CXCL1 from endothelial proteoglycans. Remarkably, mice lacking gp130 in endothelial cells had impaired histamine-induced venular permeability, which was restored by injecting anti–P-selectin mAb to prevent neutrophil rolling and arrest. Thus, excessive CXCL1 expression in gp130-deficient endothelial cells augments neutrophil adhesion but hinders migration, most likely by disrupting chemotactic gradients. Our data define a role for endothelial cell gp130 in regulating integrin-dependent adhesion and de-adhesion of neutrophils during inflammation. PMID:24081661

Entrainment of Juvenile and Adult American Shad at a Pumped Storage Facility

DOE PAGES

Mathur, Dilip; Heisey, Paul G.; Royer, Doug D.; ...

2017-12-13

The American Shad Alosa sapidissima has been targeted for restoration to the upper Susquehanna River, and entrainment losses at hydroelectric facilities on the river, including the Muddy Run Pumped Storage Facility, are of concern for the potential growth of the American Shad population. Based on the integration of pumping volume, time of entrainment, and literature–reported diel emigration of juvenile American Shad, the entrainment rate (N = 145; 53 exposed to pumping) was estimated at 3.5%. The entrainment rate for adults (N = 507) was estimated at 0.3–3.9%. Using multistate mark–recapture models, the estimated entrainment probabilities (Ψ) of radio–tagged juveniles weremore » higher during periods of extended pumping (>1 h; Ψ = 0.093; 95% confidence interval [CI] = 0.054–0.156) than at periods of no pumping or short–duration pumping (<1 h; Ψ < 0.0001; 95% CI = 0.0–0.001); the high extended pumping occurred between 2300 and 0600 hours. Entrainment probabilities for adults were low (Ψ < 0.02); the highest probability occurred for fish detected downstream of the intake during the peak portion of the run (Ψ = 0.015; 95% CI = 0.004–0.047). Entrainment probability for most adult fish did not differ from zero. The low values of Ψ for both life stages were attributed to (1) the deep location of the intake (intake ceiling >11.7 m below the water surface), (2) the surface orientation of American Shad (upper 3.1 m), (3) the low overlap between high–volume pumping and peak emigration/migration times, (4) the pumping volume relative to prevailing river flows, and (5) the prolonged, robust swimming speed of American Shad, particularly that of adults (>2.2 m/s), which exceeded the intake velocity (0.2–0.9 m/s). Entrainment of juveniles increased with co–occurrence of low incoming river flows, high pumping volume, and peak emigration times. Furthermore, quantification of migratory species’ entrainment at pumped storage facilities requires integration of diel migration/emigration times with the frequency, timing, and duration of pumping volume.« less

Active and passive migration in boring isopods Limnoria spp. (Crustacea, Peracarida) from kelp holdfasts

NASA Astrophysics Data System (ADS)

Miranda, Leonardo; Thiel, Martin

2008-10-01

Many boring isopods inhabit positively buoyant substrata (wood and algae), which float after detachment, permitting passive migration of inhabitants. Based on observations from previous studies, it was hypothesized that juvenile, subadult and male isopods migrate actively, and will rapidly abandon substrata after detachment. In contrast, reproductive females and small offspring were predicted to remain in floating substrata and thus have a high probability to disperse passively via rafting. In order to test this hypothesis, a colonization and an emigration experiment were conducted with giant kelp ( Macrocystis integrifolia), the holdfasts of which are inhabited by boring isopods from the genus Limnoria. A survey of benthic substrata in the kelp forest confirmed that limnoriids inhabited the holdfasts and did not occur in holdfast-free samples. Results of the colonization experiment showed that all life history stages of the boring isopods immigrated into young, largely uncolonized holdfasts, and after 16 weeks all holdfasts were densely colonized. In the emigration experiment, all life history stages of the isopods rapidly abandoned the detached holdfasts — already 5 min after detachment only few individuals remained in the floating holdfasts. After this initial rapid emigration of isopods, little changes in isopod abundance occurred during the following 24 h, and at the end of the experiment some individuals of all life history stages still remained in the holdfasts. These results indicate that all life history stages of Limnoria participate in both active migration and passive dispersal. It is discussed that storm-related dynamics within kelp forests may contribute to intense mixing of local populations of these burrow-dwelling isopods, and that most immigrants to young holdfasts probably are individuals emigrating from old holdfasts detached during storm events. The fact that some individuals of all life history stages and both sexes remain in floating holdfasts suggests that limnoriids could successfully reproduce during rafting journeys in floating kelp, facilitating long-distance dispersal. We propose that the coexistence of different modes of dispersal (short distance local migrations and long-distance regional dispersal) within these kelp-dwelling isopods might be advantageous in an environment where unpredictable El Niño events can cause extinction of local kelp forests.

Range and movement of resident holdover and hatchery brown trout tagged with radio transmitters in the Farmington River, Connecticut

USGS Publications Warehouse

Popoff, N.D.; Neumann, Robert M.

2005-01-01

The 5.8-km West Branch Farmington River Trout Management Area (TMA) is one of Connecticut's premier catch-and-release fisheries for brown trout Salmo trutta. However, little is known about the behavior of brown trout in this system and to what extent brown trout emigrate from the TMA. The objectives of this study were to determine the movement, range, and emigration of resident holdover and newly stocked brown trout tagged with radio transmitters in the TMA. Transmitters were implanted into 22 first-year (mean total length = 314 mm) and 25 second-year (mean total length = 432 mm) holdover brown trout. Twenty catchable-size (mean total length = 290 mm) brown trout were also implanted with transmitters and released into the TMA. The mean range (distance between the extreme upstream and downstream locations) was greater for second-year holdover brown trout than for first-year holdover brown trout, and it was greater in fall than in winter. The movement (distance moved between successive locations) of holdover brown trout was greater in fall than in winter. Movement of first-year holdover brown trout was significantly related to discharge, water temperature, and the number of days between successive locations. Newly stocked brown trout exhibited the two largest ranges (5.3 and 4.7 km). The range of newly stocked brown trout was not different between seasons, but movement was greater in spring than in summer. Through 16 weeks poststocking, there was no discernable difference in the percentage of stocked brown trout dispersing in a predominantly upstream or downstream direction. Mean dispersal distances from the stocking location were 0.5 and 0.9 km at 2 and 12 weeks poststocking, respectively. Movement of newly stocked brown trout was positively related to discharge and negatively related to water temperature. A known 6% (4 of 67) of the tagged brown trout emigrated from the TMA, but up to 21% (14 of 67) of tagged fish could have left the study area if all missing fish were emigrants. ?? Copyright by the American Fisheries Society 2005.

Entrainment of Juvenile and Adult American Shad at a Pumped Storage Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathur, Dilip; Heisey, Paul G.; Royer, Doug D.

The American Shad Alosa sapidissima has been targeted for restoration to the upper Susquehanna River, and entrainment losses at hydroelectric facilities on the river, including the Muddy Run Pumped Storage Facility, are of concern for the potential growth of the American Shad population. Based on the integration of pumping volume, time of entrainment, and literature–reported diel emigration of juvenile American Shad, the entrainment rate (N = 145; 53 exposed to pumping) was estimated at 3.5%. The entrainment rate for adults (N = 507) was estimated at 0.3–3.9%. Using multistate mark–recapture models, the estimated entrainment probabilities (Ψ) of radio–tagged juveniles weremore » higher during periods of extended pumping (>1 h; Ψ = 0.093; 95% confidence interval [CI] = 0.054–0.156) than at periods of no pumping or short–duration pumping (<1 h; Ψ < 0.0001; 95% CI = 0.0–0.001); the high extended pumping occurred between 2300 and 0600 hours. Entrainment probabilities for adults were low (Ψ < 0.02); the highest probability occurred for fish detected downstream of the intake during the peak portion of the run (Ψ = 0.015; 95% CI = 0.004–0.047). Entrainment probability for most adult fish did not differ from zero. The low values of Ψ for both life stages were attributed to (1) the deep location of the intake (intake ceiling >11.7 m below the water surface), (2) the surface orientation of American Shad (upper 3.1 m), (3) the low overlap between high–volume pumping and peak emigration/migration times, (4) the pumping volume relative to prevailing river flows, and (5) the prolonged, robust swimming speed of American Shad, particularly that of adults (>2.2 m/s), which exceeded the intake velocity (0.2–0.9 m/s). Entrainment of juveniles increased with co–occurrence of low incoming river flows, high pumping volume, and peak emigration times. Furthermore, quantification of migratory species’ entrainment at pumped storage facilities requires integration of diel migration/emigration times with the frequency, timing, and duration of pumping volume.« less

Isolation and expansion of functionally-competent cardiac progenitor cells directly from heart biopsies

PubMed Central

Davis, Darryl R; Kizana, Eddy; Terrovitis, John; Barth, Andreas S.; Zhang, Yiqiang; Smith, Rachel Ruckdeschel; Miake, Junichiro; Marbán, Eduardo

2010-01-01

The adult heart contains reservoirs of progenitor cells that express embryonic and stem cell-related antigens. While these antigenically-purified cells are promising candidates for autologous cell therapy, clinical application is hampered by their limited abundance and tedious isolation methods. Methods that involve an intermediate cardiosphere-forming step have proven successful and are being tested clinically, but it is unclear whether the cardiosphere step is necessary. Accordingly, we investigated the molecular profile and functional benefit of cells that spontaneously emigrate from cardiac tissue in primary culture. Adult Wistar-Kyoto rat hearts were minced, digested and cultured as separate anatomical regions. Loosely-adherent cells that surround the plated tissue were harvested weekly for a total of five harvests. Genetic lineage tracing demonstrated that a small proportion of the direct outgrowth from cardiac samples originates from myocardial cells. This outgrowth contains sub-populations of cells expressing embryonic (SSEA-1) and stem cell-related antigens (c-Kit, abcg2) that varied with time in culture but not with the cardiac chamber of origin. This direct outgrowth, and its expanded progeny, underwent marked in vitro angiogenic/cardiogenic differentiation and cytokine secretion (IGF-1, VGEF). In vivo effects included long-term functional benefits as gauged by MRI following cell injection in a rat model of myocardial infarction. Outgrowth cells afforded equivalent functional benefits to cardiosphere-derived cells, which require more processing steps to manufacture. These results provide the basis for a simplified and efficient process to generate autologous cardiac progenitor cells (and mesenchymal supporting cells) to augment clinically-relevant approaches for myocardial repair. PMID:20211627

A closure test for time-specific capture-recapture data

USGS Publications Warehouse

Stanley, T.R.; Burnham, K.P.

1999-01-01

The assumption of demographic closure in the analysis of capture-recapture data under closed-population models is of fundamental importance. Yet, little progress has been made in the development of omnibus tests of the closure assumption. We present a closure test for time-specific data that, in principle, tests the null hypothesis of closed-population model M(t) against the open-population Jolly-Seber model as a specific alternative. This test is chi-square, and can be decomposed into informative components that can be interpreted to determine the nature of closure violations. The test is most sensitive to permanent emigration and least sensitive to temporary emigration, and is of intermediate sensitivity to permanent or temporary immigration. This test is a versatile tool for testing the assumption of demographic closure in the analysis of capture-recapture data.

Esmeralda Energy Company, Final Scientific Technical Report, January 2008. Emigrant Slimhole Drilling Project, DOE GRED III

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deymonaz, John; Hulen, Jeffrey B.; Nash, Gregory D.

2008-01-22

The Emigrant Slimhole Drilling Project (ESDP) was a highly successful, phased resource evaluation program designed to evaluate the commercial geothermal potential of the eastern margin of the northern Fish Lake Valley pull-apart basin in west-central Nevada. The program involved three phases: (1) Resource evaluation; (2) Drilling and resource characterization; and (3) Resource testing and assessment. Efforts included detailed geologic mapping; 3-D modeling; compilation of a GIS database; and production of a conceptual geologic model followed by the successful drilling of the 2,938 foot deep 17-31 slimhole (core hole), which encountered commercial geothermal temperatures (327⁰ F) and exhibits an increasing, conductive,more » temperature gradient to total depth; completion of a short injection test; and compilation of a detailed geologic core log and revised geologic cross-sections. Results of the project greatly increased the understanding of the geologic model controlling the Emigrant geothermal resource. Information gained from the 17-31 core hole revealed the existence of commercial temperatures beneath the area in the Silver Peak Core Complex which is composed of formations that exhibit excellent reservoir characteristics. Knowledge gained from the ESDP may lead to the development of a new commercial geothermal field in Nevada. Completion of the 17-31 core hole also demonstrated the cost-effectiveness of deep core drilling as an exploration tool and the unequaled value of core in understanding the geology, mineralogy, evolutional history and structural aspects of a geothermal resource.« less

Sex and drug risk behavior pre- and post-emigration among Latino migrant men in post-Hurricane Katrina New Orleans.

PubMed

Mills, Jennifer; Burton, Nicole; Schmidt, Norine; Salinas, Oscar; Hembling, John; Aran, Alberto; Shedlin, Michele; Kissinger, Patricia

2013-06-01

High rates of sex and drug risk behaviors have been documented among Latino migrant men in the US. Whether these behaviors were established in the migrants' home countries or were adopted in the US has not been described and has implications for prevention strategies. Quarterly surveys were conducted to gather information on selected sex and drug risk practices of Latino migrant men who arrived in New Orleans after Hurricane Katrina seeking work. Both kappa scores and McNemar's tests were performed to determine if practice of these behaviors in home country was similar to practice post-emigration to the US. Female sex worker (FSW) patronage, same sex encounters (MSM), and crack cocaine use was more likely to occur post- rather than pre-emigration. Of those who ever engaged in these selected behaviors, most adopted the behavior in the US (i.e., 75.8% of FSW patrons, 72.7% of MSM participants, and 85.7% of crack cocaine users), with the exception of binge drinking (26.8%). Men who were living with a family member were less likely to adopt FSW patronage OR = 0.27, CI = 0.10-0.76, whereas men who earned >$465 per week were more likely to adopt crack cocaine use OR = 6.29 CI = 1.29, 30.57. Interventions that facilitate the maintenance of family cohesion and provide strategies for financial management may be useful for reducing sex and drug risk among newly arrived migrants.

Thailand's responses to transnational migration during economic growth and economic downturn.

PubMed

Chantavanich, S

1999-04-01

This paper gives an historical overview of immigration to Thailand since the 1970s and emigration since the 1960s. It describes migration policies since the 1930s. Final discussion focuses on the impact of economic contraction on migration. Immigration to Thailand dates back to the 1760s when a huge wave of Chinese emigrated to Thailand. The flow continued until about 1850 and resumed during 1905-17. The next big waves of immigrants were after 1975, when refugees fled Indochina, and in the 1990s, when migrants flocked from neighboring countries drawn to the booming economy. Thai professionals left in the 1960s for the USA. During the 1980s, many left for work in the Middle East. During the 1990s, Thai migrants moved within the East and Southeastern Asian countries and the USA or Europe, and they included many women and illegal migrants. Emigrants leave as arranged by the government, by employers, by recruitment agencies, and as trainees. The first official act was in 1950 and revised in 1979. Many work permits were approved in the 1990s, especially for unskilled labor. There are supports for Thai migrants abroad, but little is offered to foreigners at home. By 1997, the country's recession led to nonrenewal of many work permits. The 1998 economic crisis led to a new labor policy that deported illegal and unskilled migrant workers in order to create jobs for Thais. Policy encouraged Thais to seek work overseas.

Emigration flows from North Africa to Europe.

PubMed

Kassar, Hassène; Marzouk, Diaa; Anwar, Wagida A; Lakhoua, Chérifa; Hemminki, Kari; Khyatti, Meriem

2014-08-01

The region of North Africa (NA) represents a striking locality regarding migration with several migration patterns, namely emigration in the form of labour export to Europe and North America and, to a lesser extent, to the Arab Gulf area. The latter has increased enormously in the last decade because of the political instability in most of the NA countries. The aim of the present chapter was to explore the patterns of migration stocks and flows in NA countries, based on several websites, systematic review of journals, comparable data available by the United Nations and by the International Organization of Migration. The NA region has become an area of transit migration and labour migration. Emigrant flows from NA countries towards Europe and North America are increasing this decade more than towards the Arab Gulf countries after being replaced by Asian labour. The recent increase in the proportion of women among the migrant population is remarkable. Remittances sent by African migrants have become an important source of external finance for countries of origin. Transient and irregular migration to Egypt originates at the borders with Sudan, Palestine and Libya with destination to the Euro Mediterranean countries. In Tunisia and Morocco, irregular migrants originate from Sub-Saharan Africa to the northern borders. The NA countries serve as departure rather than destination countries, and migration flows to the Euro-Mediterranean countries through legal or illegal routes. © The Author 2014. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Disentangling the Effects of Migration, Selection and Acculturation on Weight and Body Fat Distribution: Results from a Natural Experiment involving Vietnamese Americans, Returnees, and Never-leavers

PubMed Central

Fu, Hongyun; VanLandingham, Mark J.

2012-01-01

Objective We distinguish between selection and true migration effects on weight and body fat for Vietnamese immigrants; and examine the role of acculturation on these outcomes. Methods Data (n=703) were collected among three population-based samples of working-age Vietnamese immigrants, repatriated emigrants and never-migrated Vietnamese nationals. This allows for a decomposition exercise to separate the effects of migration effects from selection effects on body mass index (BMI) and waist-hip ratio (WHR). Results Immigrants are more likely to be overweight and to have high WHR, relative to both never-leavers and returnees, a pattern reflecting the importance of migration over selection. Among immigrants, coming to the US at a younger age is associated with higher BMI and WHR levels. And longer length of residence in the US is related to higher BMI. While higher Vietnamese language proficiency is related to a lower BMI level, being bilingual (proficient in both English and Vietnamese) is associated with lower risks for being overweight. Conclusions The distinct pattern of results suggests that more problematic weight status and fat distribution among Vietnamese immigrants relative to Vietnamese nationals are not artifacts of the types of persons choosing to emigrate, but rather are due to acculturation to American diet and lifestyles. While efforts to promote and maintain traditional patterns of diet and lifestyle are likely to help Vietnamese and other immigrants avoid the perils of American patterns, facilitating a bi-cultural orientation is perhaps the most realistic approach for preserving protective features of the culture of origin with regard to body weight and fat distribution. PMID:22427069

[Headache and immigration. A study in the outpatient department of the Hospital de la Santa Creu i Sant Pau in Barcelona].

PubMed

Vidal-Jordana, A; Barroeta-Espar, I; Sainz-Pelayo, M P; Sala, I; Roig, C

2011-09-01

The immigrant population (IP) is visiting neurology departments on an increasingly more frequent basis. Research has still not made it clear whether there are geographical differences in the prevalence of primary headaches and the possible influence of emigration. We conducted a retrospective (12 months) and prospective study (18 months) of the first visits to the Headache Unit at the Hospital de la Santa Creu i Sant Pau. Data collected included the country of birth, time parameters of the headache and of the immigration, diagnoses according to the criteria of the IHS and treatments that had been used. Related headaches were considered to be those that began within one year of having immigrated. The IP represents 13.6% (n = 142) of the total number of first visits because of headaches (n = 1044). Immigrants came mostly from Latin America (83.9%). Headaches began after immigration in 40.1% of cases without the existence of any temporal relation with immigration. The distribution of the diagnoses of headache is similar to those of the local population, the most frequent being migraine (57.7%) and tension-type headache (15.5%). On comparing treatments prior to and following immigration, we find differences in the use of triptans (2.1% versus 46.2%), ergotamine (9.8% versus 2.1%) and in the use of preventive treatments (2% versus 45%). The IP accounts for 13% of all first visits due to headaches and their diagnoses are similar to those of the local population. Emigration is neither a precipitating nor an aggravating factor for headaches in our series. There is a significant difference in symptomatic and preventive treatment between the period prior to immigration and afterwards.

Technical advance: liposomal alendronate depletes monocytes and macrophages in the nonhuman primate model of human disease.

PubMed

Burwitz, Benjamin J; Reed, Jason S; Hammond, Katherine B; Ohme, Merete A; Planer, Shannon L; Legasse, Alfred W; Ericsen, Adam J; Richter, Yoram; Golomb, Gershon; Sacha, Jonah B

2014-09-01

Nonhuman primates are critical animal models for the study of human disorders and disease and offer a platform to assess the role of immune cells in pathogenesis via depletion of specific cellular subsets. However, this model is currently hindered by the lack of reagents that safely and specifically ablate myeloid cells of the monocyte/macrophage Lin. Given the central importance of macrophages in homeostasis and host immunity, development of a macrophage-depletion technique in nonhuman primates would open new avenues of research. Here, using LA at i.v. doses as low as 0.1 mg/kg, we show a >50% transient depletion of circulating monocytes and tissue-resident macrophages in RMs by an 11-color flow cytometric analysis. Diminution of monocytes was followed rapidly by emigration of monocytes from the bone marrow, leading to a rebound of monocytes to baseline levels. Importantly, LA was well-tolerated, as no adverse effects or changes in gross organ function were observed during depletion. These results advance the ex vivo study of myeloid cells by flow cytometry and pave the way for in vivo studies of monocyte/macrophage biology in nonhuman primate models of human disease. © 2014 Society for Leukocyte Biology.

Technical Advance: Liposomal alendronate depletes monocytes and macrophages in the nonhuman primate model of human disease

PubMed Central

Burwitz, Benjamin J.; Reed, Jason S.; Hammond, Katherine B.; Ohme, Merete A.; Planer, Shannon L.; Legasse, Alfred W.; Ericsen, Adam J.; Richter, Yoram; Golomb, Gershon; Sacha, Jonah B.

2014-01-01

Nonhuman primates are critical animal models for the study of human disorders and disease and offer a platform to assess the role of immune cells in pathogenesis via depletion of specific cellular subsets. However, this model is currently hindered by the lack of reagents that safely and specifically ablate myeloid cells of the monocyte/macrophage Lin. Given the central importance of macrophages in homeostasis and host immunity, development of a macrophage-depletion technique in nonhuman primates would open new avenues of research. Here, using LA at i.v. doses as low as 0.1 mg/kg, we show a >50% transient depletion of circulating monocytes and tissue-resident macrophages in RMs by an 11-color flow cytometric analysis. Diminution of monocytes was followed rapidly by emigration of monocytes from the bone marrow, leading to a rebound of monocytes to baseline levels. Importantly, LA was well-tolerated, as no adverse effects or changes in gross organ function were observed during depletion. These results advance the ex vivo study of myeloid cells by flow cytometry and pave the way for in vivo studies of monocyte/macrophage biology in nonhuman primate models of human disease. PMID:24823811

Leukotriene B4-loaded microspheres: a new therapeutic strategy to modulate cell activation

PubMed Central

Nicolete, Roberto; Rius, Cristina; Piqueras, Laura; Jose, Peter J; Sorgi, Carlos A; Soares, Edson G; Sanz, Maria J; Faccioli, Lúcia H

2008-01-01

Background Leukotriene B4 (LTB4) is a potent inflammatory mediator that also stimulates the immune response. In addition, it promotes polymorphonuclear leukocyte phagocytosis, chemotaxis, chemokinesis and modulates cytokines release. Regarding chemical instability of the leukotriene molecule, in the present study we assessed the immunomodulatory activities conferred by LTB4 released from microspheres (MS). A previous oil-in-water emulsion solvent extraction-evaporation method was chosen to prepare LTB4-loaded MS. Results In the mice cremasteric microcirculation, intraescrotal injection of 0.1 ml of LTB4-loaded MS provoked significant increases in leukocyte rolling flux, adhesion and emigration besides significant decreases in the leukocyte rolling velocity. LTB4-loaded MS also increase peroxisome proliferator-activated receptor-α (PPARα) expression by murine peritoneal macrophages and stimulate them to generate nitrite levels. Monocyte chemoattractant protein-1 (MCP-1) and nitric oxide (NO) productions were also increased when human umbilical vein and artery endothelial cells (HUVECs and HUAECs, respectively) were stimulated with LTB4-loaded MS. Conclusion LTB4-loaded MS preserve the biological activity of the encapsulated mediator indicating their use as a new strategy to modulate cell activation, especially in the innate immune response. PMID:18627613

CD4+ memory T cells retain surface expression of CD31 independently of thymic function in patients with lymphoproliferative disorders following autologous hematopoietic stem-cell transplantation.

PubMed

Batorov, Egor V; Tikhonova, Marina A; Kryuchkova, Irina V; Sergeevicheva, Vera V; Sizikova, Svetlana A; Ushakova, Galina Y; Batorova, Dariya S; Gilevich, Andrey V; Ostanin, Alexander A; Shevela, Ekaterina Y; Chernykh, Elena R

2017-07-01

High-dose chemotherapy with autologous hematopoietic stem-cell transplantation (AHSCT) causes severe and long-lasting immunodeficiency in patients with lymphoproliferative disorders. The thymus begins to restore the T-cell repertoire approximately from the sixth month post-transplant. We assessed the dynamics of post-transplant recovery of CD4 + CD45RA + CD31 + T cells, "recent thymic emigrants" (RTEs), and a poorly described subtype of CD4 + CD45RA - CD31 + T cells in 90 patients with lymphoproliferative disorders following high-dose chemotherapy with AHSCT. Relative and absolute counts of CD4 + CD31 + naïve and memory T cells were evaluated before AHSCT, at the day of engraftment, and 6- and 12-month post-transplant. The pre-transplant count of CD4 + CD45RA + CD31 + T cells was lower than in healthy controls, and did not reach donors' values during the 12-month period. The pre-transplant number of CD4 + CD45RA - CD31 + T cells was higher than in healthy controls and was restored rapidly following AHSCT. Post-transplant mediastinal radiotherapy reduced counts of RTEs and elongated recovery period. Non-thymic tissue irradiation did not reduce this subset. The obtained data indicate that homeostatic proliferation may decrease the significance of CD31 expression on CD4 + CD45RA + T cells as a marker of RTEs, and suggest that evaluation of RTEs recovery by flow cytometry requires an accurate gating strategy to exclude CD31 + memory T cells.

FK506 attenuates thymic output in patients with myasthenia gravis

PubMed Central

Kuroda, Yukiko; Ueno, Shu-ichi; Matsui, Naoko; Kaji, Ryuji

2013-01-01

Introduction Myasthenia gravis (MG) is an antibody-mediated, T-cell-dependent autoimmune disease. The symptoms are caused by high-affinity IgG against the muscle acetylcholine receptor (AChR) at the neuromuscular junction. The production of these antibodies in B-cells depends on AChR-specific CD4+ T-cells and the thymus gland seems to play a significant role in the pathogenesis of MG. Altered thymic T-cell export seems to be associated with a pathological mechanism in myasthenia gravis. Tacrolimus (FK506) has recently been used to treat MG. Material and methods We examined the effects of tacrolimus on thymic T-cell export in patients with MG. Sixteen patients with nonthymomatous and/or thymectomized MG were treated with oral administrations of tacrolimus. To assess the effect of tacrolimus on the thymic output, we assayed the levels of T-cell receptor excision circle (TREC), a molecular marker of thymus emigrants. Results T-cell receptor excision circle was not significantly different from those in age-matched controls before tacrolimus therapy, but they were partially decreased 4 months after tacrolimus therapy. T-cell receptor excision circle levels were significantly decreased in the thymomatous group (p < 0.05), but not in the nonthymomatous group. Tacrolimus treatment significantly attenuated TREC levels in cultured CD4–CD8+ cells (p < 0.05), but total cell counts were not significantly changed. Conclusions These results indicate that TREC levels may become a marker of the curative effect of tacrolimus therapy for thymomatous MG, and that tacrolimus suppresses not only activating T-lymphocytes, but also naïve T-cells. PMID:24482655

A major role for Bim in regulatory T cell homeostasis.

PubMed

Chougnet, Claire A; Tripathi, Pulak; Lages, Celine S; Raynor, Jana; Sholl, Allyson; Fink, Pamela; Plas, David R; Hildeman, David A

2011-01-01

We have previously shown that regulatory T cells (Treg) accumulate dramatically in aged animals and negatively impact the ability to control persistent infection. However, the mechanisms underlying the age-dependent accrual of Treg remain unclear. In this study, we show that Treg accumulation with age is progressive and likely not the result of increased thymic output, increased peripheral proliferation, or from enhanced peripheral conversion. Instead, we found that Treg from aged mice are more resistant to apoptosis than Treg from young mice. Although Treg from aged mice had increased expression of functional IL-7Rα, we found that IL-7R signaling was not required for maintenance of Treg in vivo. Notably, aged Treg exhibit decreased expression of the proapoptotic molecule Bim compared with Treg from young mice. Furthermore, in the absence of Bim, Treg accumulate rapidly, accounting for >25% of the CD4(+) T cell compartment by 6 mo of age. Additionally, accumulation of Treg in Bim-deficient mice occurred after the cells left the transitional recent thymic emigrant compartment. Mechanistically, we show that IL-2 drives preferential proliferation and accumulation of Bim(lo) Treg. Collectively, our data suggest that chronic stimulation by IL-2 leads to preferential expansion of Treg having low expression of Bim, which favors their survival and accumulation in aged hosts.

A major role for Bim in regulatory T cell homeostasis1

PubMed Central

Chougnet, Claire A.; Tripathi, Pulak; Lages, Celine S.; Raynor, Jana; Sholl, Allyson; Fink, Pamela; Plas, David R.; Hildeman, David A.

2011-01-01

We have previously shown that regulatory T cells (Treg) accumulate dramatically in aged animals and negatively impact the ability to control persistent infection. However, the mechanism(s) underlying the age-dependent accrual of Treg remain unclear. Here, we show that Treg accumulation with age is progressive and likely not the result of increased thymic output, increased peripheral proliferation, nor from enhanced peripheral conversion. Instead, we found that Treg from aged mice are more resistant to apoptosis than Treg from young mice. Although Treg from aged mice had increased expression of functional IL-7Rα, we found that IL-7R-signaling was not required for maintenance of Treg in vivo. Notably, aged Treg exhibit decreased expression of the pro-apoptotic molecule Bim compared to Treg from young mice. Further, in the absence of Bim, Treg accumulate rapidly, accounting for more than 25% of the CD4+ T cell compartment by 6 months of age. In addition, accumulation of Treg in Bim-deficient mice occurred after the cells left the transitional recent thymic emigrant compartment. Mechanistically, we show that IL-2 drives preferential proliferation and accumulation of Bimlo Treg. Combined, our data suggest that chronic stimulation by IL-2 leads to preferential expansion of Treg having low expression of Bim, which favors their survival and accumulation in aged hosts. PMID:21098226

Measurement of lipocortin 1 levels in murine peripheral blood leukocytes by flow cytometry: modulation by glucocorticoids and inflammation.

PubMed

Perretti, M; Flower, R J

1996-06-01

1. Lipocortin 1 (LC1) immunoreactivity in murine peripheral blood leukocytes was quantified by use of a flow cytometric technique associated with a permeabilisation protocol with saponin. Using specific antisera raised against the whole protein or against its N-terminus peptide, cell-associated LC1-like immunoreactivity was easily detected in circulating neutrophils and monocytes, whereas very low levels were found in lymphocytes. Of the total protein measured 17.6% and 36% were associated with the external plasma membrane in neutrophils and monocytes, as assessed in the absence of cell permeabilisation, whereas no signal was detected on lymphocyte plasma membrane. 2. Treatment of mice with dexamethasone (Dex; 0.5-5 micrograms per mouse corresponding to approximately 0.015-1.5 mg kg-1) increased LC1 levels in neutrophils and monocytes. The 2-3 fold increase in LC1 levels was time-dependent with a peak at 2 h. Treatment of mice with the steroid antagonist, RU486 (two doses of 20 mg kg-1 orally) decreased LC1-like immunoreactivity in all three types of circulating leukocytes by > or = 50%. 3. Extravasation of blood neutrophils into inflamed tissue sites resulted in a consistent reduction (> or = 50%) in LC1 levels compared with circulating neutrophils. A high LC1-like immunoreactivity was also measured in resident macrophages, of which approximately one third was membrane-associated. Induction of an acute inflammatory response in the murine peritoneal cavity did not modify total LC1 levels measured in macrophages, but reduced membrane-associated LC1 to a significant extent, i.e. up to 70%. 4. In conclusion, flow cytometric analysis is a rapid and convenient method for detecting and measuring LC1 in murine leukocytes. We confirmed that LC1 protein expression is controlled by exogenous and endogenous glucocorticoids. Amongst other factor(s) influencing protein concentrations, extravasation was found to be associated with a reduced LC1 expression in the emigrated cells.

Annual survival estimation of migratory songbirds confounded by incomplete breeding site-fidelity: Study designs that may help

USGS Publications Warehouse

Marshall, M.R.; Diefenbach, D.R.; Wood, L.A.; Cooper, R.J.

2004-01-01

Many species of bird exhibit varying degrees of site-fidelity to the previous year's territory or breeding area, a phenomenon we refer to as incomplete breeding site-fidelity. If the territory they occupy is located beyond the bounds of the study area or search area (i.e., they have emigrated from the study area), the bird will go undetected and is therefore indistinguishable from dead individuals in capture-mark-recapture studies. Differential emigration rates confound inferences regarding differences in survival between sexes and among species if apparent survival rates are used as estimates of true survival. Moreover, the bias introduced by using apparent survival rates for true survival rates can have profound effects on the predictions of population persistence through time, source/sink dynamics, and other aspects of life-history theory. We investigated four study design and analysis approaches that result in apparent survival estimates that are closer to true survival estimates. Our motivation for this research stemmed from a multi-year capture-recapture study of Prothonotary Warblers (Protonotaria citrea) on multiple study plots within a larger landscape of suitable breeding habitat where substantial inter-annual movements of marked individuals among neighboring study plots was documented. We wished to quantify the effects of this type of movement on annual survival estimation. The first two study designs we investigated involved marking birds in a core area and resighting them in the core as well as an area surrounding the core. For the first of these two designs, we demonstrated that as the resighting area surrounding the core gets progressively larger, and more "emigrants" are resighted, apparent survival estimates begin to approximate true survival rates (bias < 0.01). However, given observed inter-annual movements of birds, it is likely to be logistically impractical to resight birds on sufficiently large surrounding areas to minimize bias. Therefore, as an alternative protocol, we analyzed the data with subsets of three progressively larger areas surrounding the core. The data subsets provided four estimates of apparent survival that asymptotically approached true survival. This study design and analytical approach is likely to be logistically feasible in field settings and yields estimates of true survival unbiased (bias < 0.03) by incomplete breeding site-fidelity over a range of inter-annual territory movement patterns. The third approach we investigated used a robust design data collection and analysis approach. This approach resulted in estimates of survival that were unbiased (bias < 0.02), but were very imprecise and likely would not yield reliable estimates in field situations. The fourth approach utilized a fixed study area size, but modeled detection probability as a function of bird proximity to the study plot boundary (e.g., those birds closest to the edge are more likely to emigrate). This approach also resulted in estimates of survival that were unbiased (bias < 0.02), but because the individual covariates were normalized, the average capture probability was 0.50, and thus did not provide an accurate estimate of the true capture probability. Our results show that the core-area with surrounding resight-only can provide estimates of survival that are not biased by the effects of incomplete breeding site-fidelity. ?? 2004 Museu de Cie??ncies Naturals.

Interculture: Some Concepts for Describing the Situation of Immigrants.

ERIC Educational Resources Information Center

Ekstrand, Lars Henric; And Others

1981-01-01

Attempts to find new ways of describing and analyzing dynamic interactions in country of origin, host country, and immigrant community caused by migration. Analyzes linguistic models, concept of culture, emigration psychology, and identity formation. (Author/BK)

22 CFR 99.3 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false [Reserved] 99.3 Section 99.3 Foreign Relations DEPARTMENT OF STATE LEGAL AND RELATED SERVICES REPORTING ON CONVENTION AND NON-CONVENTION ADOPTIONS OF EMIGRATING CHILDREN § 99.3 [Reserved] ...

Emigration from Within.

PubMed

Szekacs-Weisz, Judit

2016-12-01

Listening to the stories of people belonging to different generations in motion-both in our consulting rooms and our personal lives-served as introductory lectures into the fundamental aspects of changing context. Through these rich and diverse stories, one enters a territory which is not only multilingual but multidimensional: defined and shaped by historical, political, economic and socio-cultural transformations. Giving voice to these silent stories proved helpful for us when going behind walls that traditional analysis could not always penetrate, partly because, in many cases, analysts and analysands have been struggling with the same untouchable issues. It is our professional task to find creative ways to make sense of past and recent experiences of emigration, new prejudices, discriminative forms and attitudes-in order to achieve a better psychoanalytical understanding of the external and internal confusion that has been brought about by the immense changes during the past centuries and the present one.

Homeostasis of naive and memory CD4+ T cells: IL-2 and IL-7 differentially regulate the balance between proliferation and Fas-mediated apoptosis.

PubMed

Jaleco, Sara; Swainson, Louise; Dardalhon, Valérie; Burjanadze, Maryam; Kinet, Sandrina; Taylor, Naomi

2003-07-01

Cytokines play a crucial role in the maintenance of polyclonal naive and memory T cell populations. It has previously been shown that ex vivo, the IL-7 cytokine induces the proliferation of naive recent thymic emigrants (RTE) isolated from umbilical cord blood but not mature adult-derived naive and memory human CD4(+) T cells. We find that the combination of IL-2 and IL-7 strongly promotes the proliferation of RTE, whereas adult CD4(+) T cells remain relatively unresponsive. Immunological activity is controlled by a balance between proliferation and apoptotic cell death. However, the relative contributions of IL-2 and IL-7 in regulating these processes in the absence of MHC/peptide signals are not known. Following exposure to either IL-2 or IL-7 alone, RTE, as well as mature naive and memory CD4(+) T cells, are rendered only minimally sensitive to Fas-mediated cell death. However, in the presence of the two cytokines, Fas engagement results in a high level of caspase-dependent apoptosis in both RTE as well as naive adult CD4(+) T cells. In contrast, equivalently treated memory CD4(+) T cells are significantly less sensitive to Fas-induced cell death. The increased susceptibility of RTE and naive CD4(+) T cells to Fas-induced apoptosis correlates with a significantly higher IL-2/IL-7-induced Fas expression on these T cell subsets than on memory CD4(+) T cells. Thus, IL-2 and IL-7 regulate homeostasis by modulating the equilibrium between proliferation and apoptotic cell death in RTE and mature naive and memory T cell subsets.

Depletion of autoreactive immunologic memory followed by autologous hematopoietic stem cell transplantation in patients with refractory SLE induces long-term remission through de novo generation of a juvenile and tolerant immune system.

PubMed

Alexander, Tobias; Thiel, Andreas; Rosen, Oliver; Massenkeil, Gero; Sattler, Arne; Kohler, Siegfried; Mei, Henrik; Radtke, Hartmut; Gromnica-Ihle, Erika; Burmester, Gerd-Rüdiger; Arnold, Renate; Radbruch, Andreas; Hiepe, Falk

2009-01-01

Clinical trials have indicated that immunoablation followed by autologous hematopoietic stem cell transplantation (ASCT) has the potential to induce clinical remission in patients with refractory systemic lupus erythematosus (SLE), but the mechanisms have remained unclear. We now report the results of a single-center prospective study of long-term immune reconstitution after ASCT in 7 patients with SLE. The clinical remissions observed in these patients are accompanied by the depletion of autoreactive immunologic memory, reflected by the disappearance of pathogenic anti-double-stranded DNA (dsDNA) antibodies and protective antibodies in serum and a fundamental resetting of the adaptive immune system. The latter comprises recurrence of CD31(+)CD45RA(+)CD4(+) T cells (recent thymic emigrants) with a doubling in absolute numbers compared with age-matched healthy controls at the 3-year follow-up (P = .016), the regeneration of thymic-derived FoxP3(+) regulatory T cells, and normalization of peripheral T-cell receptor (TCR) repertoire usage. Likewise, responders exhibited normalization of the previously disturbed B-cell homeostasis with numeric recovery of the naive B-cell compartment within 1 year after ASCT. These data are the first to demonstrate that both depletion of the autoreactive immunologic memory and a profound resetting of the adaptive immune system are required to reestablish self-tolerance in SLE.

Brain drain: final year medical students' intentions of training abroad.

PubMed

Bojanic, Ana; Bojanic, Katarina; Likic, Robert

2015-06-01

In Croatia, a new European Union (EU) member state since July 2013, there is already a shortage of around 3280 doctors to reach the European average. To investigate the emigration intentions of the current cohort of final year medical students at Zabreb School of Medicine. An electronic questionnaire was used in June 2013 to assess the attitudes of 232 final year medical students towards working conditions abroad and expectations for career opportunities in Croatia following accession to the EU. With an overall response rate of 87%, more than half of the surveyed students (106/202, 53%) intended to travel abroad, either for specialty (52/202, 26%) or subspecialty (54/202, 27%) training. More female students (58/135, 43%) than male students (17/62, 27%) indicated they would not emigrate. Most attractive emigration destinations were: Germany (34/121, 28%), USA (19/121, 16%), the UK (19/121, 16%), Switzerland (16/121, 13%) and Canada (11/121, 9%). The most important goals that respondents aimed to achieve through training abroad were to excel professionally (45/120, 38%), to prosper financially (20/120, 17%) and to acquire new experiences and international exposure (31/120, 26%). Students' motivating factors, goals for and positive beliefs about training abroad, as well as negative expectations regarding career opportunities in Croatia, may point towards actions that could be taken to help make Croatia a country that facilitates medical education and professional career development of young doctors. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

How stock of origin affects performance of individuals across a meta-ecosystem: an example from sockeye salmon.

PubMed

Griffiths, Jennifer R; Schindler, Daniel E; Seeb, Lisa W

2013-01-01

Connectivity among diverse habitats can buffer populations from adverse environmental conditions, influence the functioning of meta-ecosystems, and ultimately affect the reliability of ecosystem services. This stabilizing effect on populations is proposed to derive from complementarity in growth and survival conditions experienced by individuals in the different habitats that comprise meta-ecosystems. Here we use the fine scale differentiation of salmon populations between diverse lake habitats to assess how rearing habitat and stock of origin affect the body condition of juvenile sockeye salmon. We use genetic markers (single nucleotide polymorphisms) to assign individuals of unknown origin to stock group and in turn characterize ecologically relevant attributes across habitats and stocks. Our analyses show that the body condition of juvenile salmon is related to the productivity of alternative habitats across the watershed, irrespective of their stock of origin. Emigrants and residents with genetic origins in the high productivity lake were also differentiated by their body condition, poor and high respectively. These emigrants represented a substantial proportion of juvenile sockeye salmon rearing in the lower productivity lake habitat. Despite emigrants originating from the more productive lake, they did not differ in body condition from the individuals spawned in the lower productivity, recipient habitat. Genetic tools allowed us to assess the performance of different stocks groups across the diverse habitats comprising their meta-ecosystem. The ability to characterize the ecological consequences of meta-ecosystem connectivity can help develop strategies to protect and restore ecosystems and the services they provide to humans.

[Clinical, biochemical and allergological indices characterizing occupational diseases of the bronchial and pulmonary system in employees at aluminium production].

PubMed

Kudaeva, I V; Dyakovich, O A; Beygel, E A; Masnavieva, L B; Naumova, O V; Budarina, L A

There are many harmful factors that possess a damaging impact on the body of employees at aluminum production. It leads to the development of bronchial asthma (BA), chronic nonobstructive bronchitis (CNB) and chronic obstructive pulmonary disease (COPD). The pathogenesis of these disorders, as well as sensitizing effect offluorine in the aluminum production is not fully understood. The purpose of this work was to study the characteristics of laboratory indices in patients with occupational diseases of the respiratory system. In workers of aluminum production with the diagnosis of occupational diseases of respiratory system (15 patients with a diagnosis of asthma, 30 CNB cases, 20 COPD patients) we evaluated the content of total protein, total cholesterol, high density lipoprotein cholesterol (HDLC), total calcium, phosphorus, ceruloplasmin, hematological indices and performed emigration of leukocytes braking test (TTEEL). Clinical and biochemical profile ofpersons with occupational asthma was characterized by a low level of total calcium and ceruloplasmin, a high concentration of phosphorus in the blood serum and inhibition of leukocyte emigration in the test with sodium fluoride. For aluminum production CNB workers characteristic active proatherogenic process was pronounced by a decrease in the HDLC level and an increase in atherogenic index; higher hematocrit value and concentration of erythrocytes, and more than 50% of cases of sensitization to the presence of sodium fluoride. COPD cases had occupational lower average concentration of hemoglobin in the erythrocyte, total protein in serum, as well as polymorphic variant response to sodium fluoride in the form of a depression and activation of leucocytes emigration.

Winter severity and phenology of spring emergence from the nest in freshwater turtles.

PubMed

Baker, Patrick Joseph; Iverson, John B; Lee, Richard E; Costanzo, Jon P

2010-07-01

Although many species of freshwater turtles emigrate to water soon after hatching, the offspring of some species overwinter on land and move to aquatic habitats in the following spring. Timing of emigration can affect the hatchlings' fitness, but the factors underlying phenology of nest emergence are incompletely understood. We tested the supposition that cold stress imposed during hibernation can influence the timing of nest emergence in three species of turtles in the central USA. In each year of the 6-year study, Chrysemys picta emerged in late March and early April and, on average, these hatchlings left their nests 2 weeks earlier than those of Graptemys geographica and 4 weeks earlier than those of Trachemys scripta. Emergence of conspecific hatchlings from different nests usually occurred over 3-7 weeks, but in some years lasted several additional weeks. Relatively few nests had siblings that emerged on the same day (i.e., synchronously); complete emergence of the typical sibling group required 1 to 2 weeks. In winter, subzero cold occurred with regularity in the nests of all species, though C. picta experienced the lowest temperatures owing to their shallower nests. However, for no species did emergence date or length of the emergence period correlate with winter minimum temperature and, at the level of the individual nest, neither did emergence synchrony or duration. Despite encountering lower temperatures, hatchlings of C. picta emigrated from their nests before those of sympatric species, suggesting that the fitness benefits of early emergence may lead to the improvement of cold-hardiness adaptations in northern populations of turtles.

How Stock of Origin Affects Performance of Individuals across a Meta-Ecosystem: An Example from Sockeye Salmon

PubMed Central

Griffiths, Jennifer R.; Schindler, Daniel E.; Seeb, Lisa W.

2013-01-01

Connectivity among diverse habitats can buffer populations from adverse environmental conditions, influence the functioning of meta-ecosystems, and ultimately affect the reliability of ecosystem services. This stabilizing effect on populations is proposed to derive from complementarity in growth and survival conditions experienced by individuals in the different habitats that comprise meta-ecosystems. Here we use the fine scale differentiation of salmon populations between diverse lake habitats to assess how rearing habitat and stock of origin affect the body condition of juvenile sockeye salmon. We use genetic markers (single nucleotide polymorphisms) to assign individuals of unknown origin to stock group and in turn characterize ecologically relevant attributes across habitats and stocks. Our analyses show that the body condition of juvenile salmon is related to the productivity of alternative habitats across the watershed, irrespective of their stock of origin. Emigrants and residents with genetic origins in the high productivity lake were also differentiated by their body condition, poor and high respectively. These emigrants represented a substantial proportion of juvenile sockeye salmon rearing in the lower productivity lake habitat. Despite emigrants originating from the more productive lake, they did not differ in body condition from the individuals spawned in the lower productivity, recipient habitat. Genetic tools allowed us to assess the performance of different stocks groups across the diverse habitats comprising their meta-ecosystem. The ability to characterize the ecological consequences of meta-ecosystem connectivity can help develop strategies to protect and restore ecosystems and the services they provide to humans. PMID:23505539

Winter severity and phenology of spring emergence from the nest in freshwater turtles

NASA Astrophysics Data System (ADS)

Baker, Patrick Joseph; Iverson, John B.; Lee, Richard E.; Costanzo, Jon P.

2010-07-01

Although many species of freshwater turtles emigrate to water soon after hatching, the offspring of some species overwinter on land and move to aquatic habitats in the following spring. Timing of emigration can affect the hatchlings’ fitness, but the factors underlying phenology of nest emergence are incompletely understood. We tested the supposition that cold stress imposed during hibernation can influence the timing of nest emergence in three species of turtles in the central USA. In each year of the 6-year study, Chrysemys picta emerged in late March and early April and, on average, these hatchlings left their nests 2 weeks earlier than those of Graptemys geographica and 4 weeks earlier than those of Trachemys scripta. Emergence of conspecific hatchlings from different nests usually occurred over 3-7 weeks, but in some years lasted several additional weeks. Relatively few nests had siblings that emerged on the same day (i.e., synchronously); complete emergence of the typical sibling group required 1 to 2 weeks. In winter, subzero cold occurred with regularity in the nests of all species, though C. picta experienced the lowest temperatures owing to their shallower nests. However, for no species did emergence date or length of the emergence period correlate with winter minimum temperature and, at the level of the individual nest, neither did emergence synchrony or duration. Despite encountering lower temperatures, hatchlings of C. picta emigrated from their nests before those of sympatric species, suggesting that the fitness benefits of early emergence may lead to the improvement of cold-hardiness adaptations in northern populations of turtles.

Sex and drug risk behavior pre- and post-emigration among Latino migrant men in post-Hurricane Katrina New Orleans

PubMed Central

Mills, Jennifer; Burton, Nicole; Schmidt, Norine; Salinas, Oscar; Hembling, John; Aran, Alberto; Shedlin, Michele; Kissinger, Patricia

2012-01-01

High rates of sex and drug risk behaviors have been documented among Latino migrant men in the U.S. Whether these behaviors were established in the migrants’ home countries or were adopted in the U.S. has not been described and has implications for prevention strategies. Quarterly surveys were conducted to gather information on selected sex and drug risk practices of Latino migrant men who arrived in New Orleans after Hurricane Katrina seeking work. Both kappa scores and McNemar’s tests were performed to determine if practice of these behaviors in home country was similar to practice post-emigration to the U.S. Female sex worker (FSW) patronage, same sex encounters (MSM), and crack cocaine use was more likely to occur post-rather than pre-emigration. Of those who ever engaged in these selected behaviors, most adopted the behavior in the U.S. (i.e. 75.8% of FSW patrons, 72.7% of MSM participants, and 85.7% of crack cocaine users), with the exception of binge drinking (26.8%). Men who were living with a family member were less likely to adopt FSW patronage OR=0.27, CI=0.10-0.76, whereas men who earned >$465 per week were more likely to adopt crack cocaine use OR=6.29 CI=1.29, 30.57. Interventions that facilitate the maintenance of family cohesion and provide strategies for financial management may be useful for reducing sex and drug risk among newly arrived migrants. PMID:22669638

Undocumented Aliens: A Study of Mexican Families.

ERIC Educational Resources Information Center

Salcido, Ramon M.

1979-01-01

The personal histories described here confirm that the primary impetus of undocumented aliens to emigrate is the desire for jobs and better socioeconomic opportunities. Amnesty, aid to families with dependent children, and increased social services are recommended. (Author/BEF)

Speed versus accuracy in decision-making ants: expediting politics and policy implementation.

PubMed

Franks, Nigel R; Dechaume-Moncharmont, François-Xavier; Hanmore, Emma; Reynolds, Jocelyn K

2009-03-27

Compromises between speed and accuracy are seemingly inevitable in decision-making when accuracy depends on time-consuming information gathering. In collective decision-making, such compromises are especially likely because information is shared to determine corporate policy. This political process will also take time. Speed-accuracy trade-offs occur among house-hunting rock ants, Temnothorax albipennis. A key aspect of their decision-making is quorum sensing in a potential new nest. Finding a sufficient number of nest-mates, i.e. a quorum threshold (QT), in a potential nest site indicates that many ants find it suitable. Quorum sensing collates information. However, the QT is also used as a switch, from recruitment of nest-mates to their new home by slow tandem running, to recruitment by carrying, which is three times faster. Although tandem running is slow, it effectively enables one successful ant to lead and teach another the route between the nests. Tandem running creates positive feedback; more and more ants are shown the way, as tandem followers become, in turn, tandem leaders. The resulting corps of trained ants can then quickly carry their nest-mates; but carried ants do not learn the route. Therefore, the QT seems to set both the amount of information gathered and the speed of the emigration. Low QTs might cause more errors and a slower emigration--the worst possible outcome. This possible paradox of quick decisions leading to slow implementation might be resolved if the ants could deploy another positive-feedback recruitment process when they have used a low QT. Reverse tandem runs occur after carrying has begun and lead ants back from the new nest to the old one. Here we show experimentally that reverse tandem runs can bring lost scouts into an active role in emigrations and can help to maintain high-speed emigrations. Thus, in rock ants, although quick decision-making and rapid implementation of choices are initially in opposition, a third recruitment method can restore rapid implementation after a snap decision. This work reveals a principle of widespread importance: the dynamics of collective decision-making (i.e. the politics) and the dynamics of policy implementation are sometimes intertwined, and only by analysing the mechanisms of both can we understand certain forms of adaptive organization.

Novel mode of action of the calcium antagonist mibefradil (Ro 40-5967): potent immunosuppression by inhibition of T-cell infiltration through allogeneic endothelium.

PubMed Central

Blaheta, R A; Hailer, N P; Brude, N; Wittig, B; Oppermann, E; Leckel, K; Harder, S; Scholz, M; Weber, S; Encke, A; Markus, B H

1998-01-01

Cyclosporin A reduces the mitotic activity of allosensitized lymphocytes, but fails to limit emigration of these cells into the donor organ. However, the modulation of both lymphocyte proliferation and infiltration are desirable characteristics of immunosuppressive therapy. The calcium-channel blocker, verapamil, has recently been shown to effectively prevent the transmigration of CD4+ and CD8+ T cells through allogeneic endothelium. Mibefradil (Ro 40-5967) represents a new generation of calcium antagonists with high potency and long-term activity. To evaluate the immunosuppressive potential of this drug, the influence of mibefradil on lymphocyte adhesion to, horizontal locomotion along, and penetration through allogeneic endothelium (HUVEC) was performed. When lymphocytes were prestimulated for 24 hr with mibefradil, adhesion and penetration were dose-dependently reduced. The adhesion ID50 values were 3.4 microM (CD4+ T cells) versus 9.2 microM (CD8+ T cells) and 2.1 microM (CD4+ T cells) versus 3.9 microM (CD8+ T cells) with regard to penetration. Mibefradil also effectively blocked horizontal locomotion. Specific down-regulation of T-cell binding to the P-selection receptor (ID50: CD4+ T cells, 0.8 microM: CD8+ T cells, 1.2 microM) and to the intracellular adhesion molecule-1 (ICAM-1) receptor (ID50: CD4+ T cells, 1.9 microM; CD8+ T cells, 1.5 microM) by mibefradil seems to be responsible for the decreased adhesion and penetration rates. Reduction of intracellular F-actin in T lymphocytes could diminish cell locomotion. In conclusion, the potent suppressive properties of mibefradil support its use as a co-medication in cyclosporin A-based immunosuppressive therapy. PMID:9741343

Novel mode of action of the calcium antagonist mibefradil (Ro 40-5967): potent immunosuppression by inhibition of T-cell infiltration through allogeneic endothelium.

PubMed

Blaheta, R A; Hailer, N P; Brude, N; Wittig, B; Oppermann, E; Leckel, K; Harder, S; Scholz, M; Weber, S; Encke, A; Markus, B H

1998-06-01

Cyclosporin A reduces the mitotic activity of allosensitized lymphocytes, but fails to limit emigration of these cells into the donor organ. However, the modulation of both lymphocyte proliferation and infiltration are desirable characteristics of immunosuppressive therapy. The calcium-channel blocker, verapamil, has recently been shown to effectively prevent the transmigration of CD4+ and CD8+ T cells through allogeneic endothelium. Mibefradil (Ro 40-5967) represents a new generation of calcium antagonists with high potency and long-term activity. To evaluate the immunosuppressive potential of this drug, the influence of mibefradil on lymphocyte adhesion to, horizontal locomotion along, and penetration through allogeneic endothelium (HUVEC) was performed. When lymphocytes were prestimulated for 24 hr with mibefradil, adhesion and penetration were dose-dependently reduced. The adhesion ID50 values were 3.4 microM (CD4+ T cells) versus 9.2 microM (CD8+ T cells) and 2.1 microM (CD4+ T cells) versus 3.9 microM (CD8+ T cells) with regard to penetration. Mibefradil also effectively blocked horizontal locomotion. Specific down-regulation of T-cell binding to the P-selection receptor (ID50: CD4+ T cells, 0.8 microM: CD8+ T cells, 1.2 microM) and to the intracellular adhesion molecule-1 (ICAM-1) receptor (ID50: CD4+ T cells, 1.9 microM; CD8+ T cells, 1.5 microM) by mibefradil seems to be responsible for the decreased adhesion and penetration rates. Reduction of intracellular F-actin in T lymphocytes could diminish cell locomotion. In conclusion, the potent suppressive properties of mibefradil support its use as a co-medication in cyclosporin A-based immunosuppressive therapy.

Zimbabwe: The Power Sharing Agreement and Implications for U.S. Policy

DTIC Science & Technology

2010-02-24

Zimbabweans have emigrated in the last decade, including up to half of the country’s doctors and nurses . Hospitals and clinics lack basic medicines... rescheduling , or 111 Seventy-seven individuals were named in the executive order (EO

The investigation of CD4+T-cell functions in primary HIV infection with antiretroviral therapy

PubMed Central

Sun, Yu; Fu, Yajing; Zhang, Zining; Tang, Tian; Liu, Jing; Ding, Haibo; Han, Xiaoxu; Xu, Junjie; Chu, Zhenxing; Shang, Hong; Jiang, Yongjun

2017-01-01

Abstract Human immunodeficiency virus (HIV) infection leads to reduced CD4+T-cell counts and immune dysfunction. Initiation of antiretroviral therapy (ART) in HIV primary infection has been recommended to achieve an optimal clinical outcome, but a comprehensive study on restoration of CD4+T-cell function in primary HIV-infected individuals with ART still needs to be eluciated. We investigated longitudinal changes in the CD4+T-cell counts, phenotypes, and functions in HIV-infected individuals with early ART (initiated within 6 months after HIV infection) or later ART (initiated more than 12 months after HIV infection). Patients from early ART and later ART groups had received ART for at least 1 year. Individuals with early ART had more CD4+T cells, a faster rate of CD4+T-cell recovery than those receiving later ART; the levels of CD4+T-cell activation and senescence were lower in early ART compared to those with later ART (P = .031; P = .016), but the activation was higher than normal controls (NC) (P = .001); thymic emigrant function was more upregulated in early ART than in later ART (P = .015), but still lower than NC (P = .027); proliferative capacity and interferon-γ secretion of CD4+T cells were significantly decreased in primary infection (P < .001; P = .029), and early ART restored these CD4+T-cell functions, there is no difference with NC, later ART could partially restore the functions of CD4+T cells, but it remained lower than that of NC (P = .005; P = .019). Early ART could better improve CD4+T-cell function. PMID:28700479

Vasospasm of atherosclerotic coronary arteries precipitates acute ischemic myocardial damage in myocardial infarction-prone strain of the Watanabe heritable hyperlipidemic rabbits.

PubMed

Shiomi, Masashi; Ishida, Tatsuro; Kobayashi, Tsutomu; Nitta, Norihisa; Sonoda, Akinaga; Yamada, Satoshi; Koike, Tomonari; Kuniyoshi, Nobue; Murata, Kiyoshi; Hirata, Ken-ichi; Ito, Takashi; Libby, Peter

2013-11-01

This study tested the hypothesis that vasospasm can trigger coronary plaque injury and acute ischemic myocardial damage. Myocardial infarction-prone strain of the Watanabe heritable hyperlipidemic rabbits received an intravenous bolus of ergonovine maleate (0.45 µmol/kg) during intravenous infusion of norepinephrine (12 nmol/kg per minute) to provoke coronary spasm in vivo. After this treatment, coronary angiography demonstrated vasospasm, and the ECG showed ischemic abnormalities (ST depression/elevation and T-wave inversion) in 77% of animals (23/30). These changes normalized after nitroglycerin injection. In rabbits that demonstrated these ECG findings for >20 minutes, echocardiograms showed left ventricular wall motion abnormality. Serum levels of heart-type fatty acid-binding protein, cardiac troponin-I, and myoglobin increased markedly 4 hours after spasm provocation. In coronary lesions of myocardial infarction-prone strain of the Watanabe heritable hyperlipidemic rabbits with provoked coronary spasm, we observed intimal injury in 60.9% in the form of endothelial cell protrusions (39.1%), denudation (30.4%), and macrophage extravasation (56.5%). Plaque disruption with luminal thrombus, however, was only seen in 2 of 23 animals (8.7%), and mural microthrombus was rarely observed (4.3%). These observations show that provocation of vasospasm in myocardial infarction-prone strain of the Watanabe heritable hyperlipidemic rabbits associates with subsequent ischemic myocardial damage. Although treatment with spasmogens altered aspects of plaque morphology, for example, endothelial protrusion and macrophage emigration, thrombosis was rare in these animals with chronic atherosclerotic disease.

Global Personality Norms: Multicultural, Multinational, and Managerial

ERIC Educational Resources Information Center

Oswald, Frederick L.

2008-01-01

The critical importance of understanding, selecting, and developing global management talent--management operating within internationally diverse interpersonal and situational contexts--has emerged from the increasing globalization of business and the concomitant high rates of immigration, emigration, and expatriation. With an awareness of this…

Waterfowl mortality factors

USGS Publications Warehouse

Nichols, J.D.; Beattie, Kirk H.

1989-01-01

The objectives of waterfowl management in North America involve population size and harvest. Any management action intended to influence population size must do so through one of four demographic variables: reproduction, mortality, immigration, and emigration. Mortality is especially important because hunting can be strongly influenced by management.

Why Excess Immigration Damages the Environment.

ERIC Educational Resources Information Center

Population-Environment Balance

1992-01-01

Explores the relationship between excessive immigration and environmental degradation. Explains the position that a stable United States population size is essential in prevention further deterioration of the natural resource base. Maintains that balancing immigration and emigration will be instrumental in balancing population with environment.…

Food and History: Teaching Social History Through the Study of Cuisine Patterns

ERIC Educational Resources Information Center

Gordon, Bertram M.

1974-01-01

Some interesting relationships between food and history -- working women and convenience food, exploration and the importation of new vegetables, reliance on potatoes and Irish emigration -- are suggested to indicate the usefulness of exploring history through eating habits. (JH)

A trail pheromone component of the ant Mayriella overbecki Viehmeyer (Formicidae: Myrmicinae)

NASA Astrophysics Data System (ADS)

Kohl, E.; Hölldobler, B.; Bestmann, H.-J.

The myrmicine ant Mayriella overbecki lays recruitment trails during foraging and nest emigrations. The trail pheromone originates from the poison gland. From ten identified components of the poison gland secretions only methyl 6-methylsalicylate 1 elicited trail following behavior.

Stereo Pair: Wellington, New Zealand

NASA Image and Video Library

2000-05-11

Wellington, the capital city of New Zealand, is located on the shores of Port Nicholson, a natural harbor at the south end of North Island. The city was founded in 1840 by British emigrants and now has a regional population of more than 400,000 residents.

Nursing student plans for the future after graduation: a multicentre study.

PubMed

Palese, A; Falomo, M; Brugnolli, A; Mecugni, D; Marognolli, O; Montalti, S; Tameni, A; Gonella, S; Dimonte, V

2017-03-01

When modelling the nursing workforce, estimations of the numbers and characteristics of new graduates over the forecast period are assumed on the basis of previous generations; however, new graduates may have different plans for their future than those documented previously in different socio-economical contexts. To explore (a) nursing student plans after graduation and factors influencing their plans, and (b) factors associated with the intention to emigrate. A survey questionnaire was developed and distributed to students attending their final third year of nursing education in seven universities in Italy in 2015. Nine hundred and twenty-three (90.4%) students participated. Four different plans after graduation emerged: about two-thirds reported an intention to look for a nursing job in Italy; the remaining reported (a) an intention to emigrate, looking for a nursing job abroad, (b) an intention to search for a nursing job in both Italy and abroad, and (c) while a few an intention to continue nursing education in Italy. Having previous experience abroad, the need to grow and be satisfied, trusting the target country and a desire to increase knowledge encouraged an intention to emigrate, whereas the desire to stay in a comfortable environment and nurture personal relationships prevented the desire to migrate. Nursing students may have different plans after graduation, and this should be considered when modelling the nursing workforce of the future. Policymakers should be aware of different plans after graduation to guide healthcare human resource strategies. Knowing these trajectories allows policymakers to estimate the appropriate nursing workforce, and also to act at both macro- and meso-levels, on work environments and opportunities for professional development, according to the different levels of expectations. © 2016 International Council of Nurses.

Use of Fatty Acid Analysis to Determine Dispersal of Caspian Terns in the Columbia River Basin, U.S.A.

USGS Publications Warehouse

Maranto, C.J.; Parrish, J.K.; Herman, D.P.; Punt, A.E.; Olden, J.D.; Brett, M.T.; Roby, D.D.

2011-01-01

Lethal control, which has been used to reduce local abundances of animals in conflict with humans or with endangered species, may not achieve management goals if animal movement is not considered. In populations with emigration and immigration, lethal control may induce compensatory immigration, if the source of attraction remains unchanged. Within the Columbia River Basin (Washington, U.S.A.), avian predators forage at dams because dams tend to reduce rates of emigration of juvenile salmonids (Oncorhynchus spp.), artificially concentrating these prey. We used differences in fatty acid profiles between Caspian Terns (Hydroprogne caspia) at coastal and inland breeding colonies and terns culled by a lethal control program at a mid-Columbia River dam to infer dispersal patterns. We modeled the rate of loss of fatty acid biomarkers, which are fatty acids that can be traced to a single prey species or groups of species, to infer whether and when terns foraging at dams had emigrated from the coast. Nonmetric multidimensional scaling showed that coastal terns had high levels of C20 and C22 monounsaturated fatty acids, whereas fatty acids of inland breeders were high in C18:3n3, C20:4n6, and C22:5n3. Models of the rate of loss of fatty acid showed that approximately 60% of the terns collected at Rock Island Dam were unlikely to have bred successfully at local (inland) sites, suggesting that terns foraging at dams come from an extensive area. Fatty acid biomarkers may provide accurate information about patterns of dispersal in animal populations and may be extremely valuable in cases where populations differ demonstrably in prey base. ??2011 Society for Conservation Biology.

Principal locations of major-ion, trace-element, nitrate, and Escherichia coli loading to Emigration Creek, Salt Lake County, Utah, October 2005

USGS Publications Warehouse

Kimball, Briant A.; Runkel, Robert L.; Walton-Day, Katherine

2008-01-01

Housing development and recreational activity in Emigration Canyon have increased substantially since 1980, perhaps causing an observed decrease in water quality of this northern Utah stream located near Salt Lake City. To identify reaches of the stream that contribute to water-quality degradation, a tracer-injection and synoptic-sampling study was done to quantify mass loading of major ions, trace elements, nitrate, and Escherichia coli (E. coli) to the stream. The resulting mass-loading profiles for major ions and trace elements indicate both geologic and anthropogenic inputs to the stream, principally from tributary and spring inflows to the stream at Brigham Fork, Burr Fork, Wagner Spring, Emigration Tunnel Spring, Blacksmith Hollow, and Killyon Canyon. The pattern of nitrate loading does not correspond to the major-ion and trace-element loading patterns. Nitrate levels in the stream did not exceed water-quality standards at the time of synoptic sampling. The majority of nitrate mass loading can be considered related to anthropogenic input, based on the field settings and trends in stable isotope ratios of nitrogen. The pattern of E. coli loading does not correspond to the major-ion, trace-element, or nitrate loading patterns. The majority of E. coli loading was related to anthropogenic sources based on field setting, but a considerable part of the loading also comes from possible animal sources in Killyon Canyon, in Perkins Flat, and in Rotary Park. In this late summer sampling, E. coli concentrations only exceeded water-quality standards in limited sections of the study reach. The mass-loading approach used in this study provides a means to design future studies and to evaluate the loading on a catchment scale.

Use of fatty acid analysis to determine dispersal of caspian terns in the Columbia River Basin, USA.

PubMed

Maranto, Christina J; Parrish, Julia K; Herman, David P; Punt, André E; Olden, Julian D; Brett, Michael T; Roby, Daniel D

2011-08-01

Lethal control, which has been used to reduce local abundances of animals in conflict with humans or with endangered species, may not achieve management goals if animal movement is not considered. In populations with emigration and immigration, lethal control may induce compensatory immigration, if the source of attraction remains unchanged. Within the Columbia River Basin (Washington, U.S.A.), avian predators forage at dams because dams tend to reduce rates of emigration of juvenile salmonids (Oncorhynchus spp.), artificially concentrating these prey. We used differences in fatty acid profiles between Caspian Terns (Hydroprogne caspia) at coastal and inland breeding colonies and terns culled by a lethal control program at a mid-Columbia River dam to infer dispersal patterns. We modeled the rate of loss of fatty acid biomarkers, which are fatty acids that can be traced to a single prey species or groups of species, to infer whether and when terns foraging at dams had emigrated from the coast. Nonmetric multidimensional scaling showed that coastal terns had high levels of C(20) and C(22) monounsaturated fatty acids, whereas fatty acids of inland breeders were high in C18:3n3, C20:4n6, and C22:5n3. Models of the rate of loss of fatty acid showed that approximately 60% of the terns collected at Rock Island Dam were unlikely to have bred successfully at local (inland) sites, suggesting that terns foraging at dams come from an extensive area. Fatty acid biomarkers may provide accurate information about patterns of dispersal in animal populations and may be extremely valuable in cases where populations differ demonstrably in prey base. © 2011 Society for Conservation Biology.

Incorporating movement patterns to improve survival estimates for juvenile bull trout

USGS Publications Warehouse

Bowerman, Tracy; Budy, Phaedra

2012-01-01

Populations of many fish species are sensitive to changes in vital rates during early life stages, but our understanding of the factors affecting growth, survival, and movement patterns is often extremely limited for juvenile fish. These critical information gaps are particularly evident for bull trout Salvelinus confluentus, a threatened Pacific Northwest char. We combined several active and passive mark–recapture and resight techniques to assess migration rates and estimate survival for juvenile bull trout (70–170 mm total length). We evaluated the relative performance of multiple survival estimation techniques by comparing results from a common Cormack–Jolly–Seber (CJS) model, the less widely used Barker model, and a simple return rate (an index of survival). Juvenile bull trout of all sizes emigrated from their natal habitat throughout the year, and thereafter migrated up to 50 km downstream. With the CJS model, high emigration rates led to an extreme underestimate of apparent survival, a combined estimate of site fidelity and survival. In contrast, the Barker model, which allows survival and emigration to be modeled as separate parameters, produced estimates of survival that were much less biased than the return rate. Estimates of age-class-specific annual survival from the Barker model based on all available data were 0.218±0.028 (estimate±SE) for age-1 bull trout and 0.231±0.065 for age-2 bull trout. This research demonstrates the importance of incorporating movement patterns into survival analyses, and we provide one of the first field-based estimates of juvenile bull trout annual survival in relatively pristine rearing conditions. These estimates can provide a baseline for comparison with future studies in more impacted systems and will help managers develop reliable stage-structured population models to evaluate future recovery strategies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Copeland, Timothy; Putnam, Scott

The goal of Idaho Steelhead Monitoring and Evaluation Studies is to collect monitoring data to evaluate wild and natural steelhead populations in the Clearwater and Salmon river drainages. During 2007, intensive population data were collected in Fish Creek (Lochsa River tributary) and Rapid River (Little Salmon River tributary); extensive data were collected in other selected spawning tributaries. Weirs were operated in Fish Creek and Rapid River to estimate adult escapement and to collect samples for age determination and genetic analysis. Snorkel surveys were conducted in Fish Creek, Rapid River, and Boulder Creek (Little Salmon River tributary) to estimate parr density.more » Screw traps were operated in Fish Creek, Rapid River, Secesh River, and Big Creek to estimate juvenile emigrant abundance, to tag fish for survival estimation, and to collect samples for age determination and genetic analysis. The estimated wild adult steelhead escapement in Fish Creek was 81 fish and in Rapid River was 32 fish. We estimate that juvenile emigration was 24,127 fish from Fish Creek; 5,632 fish from Rapid River; and 43,674 fish from Big Creek. The Secesh trap was pulled for an extended period due to wildfires, so we did not estimate emigrant abundance for that location. In cooperation with Idaho Supplementation Studies, trap tenders PIT tagged 25,618 steelhead juveniles at 18 screw trap sites in the Clearwater and Salmon river drainages. To estimate age composition, 143 adult steelhead and 5,082 juvenile steelhead scale samples were collected. At the time of this report, 114 adult and 1,642 juvenile samples have been aged. Project personnel collected genetic samples from 122 adults and 839 juveniles. We sent 678 genetic samples to the IDFG Eagle Fish Genetics Laboratory for analysis. Water temperature was recorded at 37 locations in the Clearwater and Salmon river drainages.« less

Feeding habitats of the Gulf sturgeon, Acipenser oxyrinchus desotoi, in the Suwannee and Yellow rivers, Florida, as identified by multiple stable isotope analyses

USGS Publications Warehouse

Sulak, Kenneth J.; Berg, James J.; Randall, Michael T.

2012-01-01

Stable 13C, 15N, and 34S isotopes were analyzed to define the feeding habitats of Acipenser oxyrinchus desotoi in the Suwannee and Yellow River populations. For the majority (93.9%) of Suwannee subadults and adults, 13C and 34S signatures indicate use of nearshore marine waters as primary winter feeding habitat, probably due to the limiting size of the Suwannee Sound estuary. In the Yellow River population, 13C isotope signatures indicate that adults remain primarily within Pensacola Bay estuary to feed in winter, rather than emigrating to the open Gulf of Mexico. A minor Suwannee River subset (6% of samples), comprised of juveniles and subadults, displayed 13C signatures indicating continued feeding in freshwater during the spring immigration and fall emigration periods. This cannot be interpreted as incidental feeding since it resulted in a 20.5% turnover in tissue δ13C signatures over a 1–3 month period. Cessation of feeding in the general population does not coincide with high river water temperatures. The hypothesis of reduced feeding in freshwater due to localized prey depletion as a result of spatial activity restriction is not supported by the present study. Instead, Suwannee River A. o. desotoi appear to follow two trophic alternatives; 1) complete cessation of feeding immediately upon immigration in spring, continuing through emigration 8–9 months later (the predominant alternative); 2) continued intensive feeding for 1–3 months following immigration, switching to freshwater prey, selected primarily from high trophic levels (i.e., large prey). Stable –34S data verifies that recently immigrated, fully-anadromous A. o. desotoi adults had fed in nearshore marine waters, not offshore waters.

[Histochemical and histoenzymatic study of experimental endarteritis in rabbits. I. Femoral endarteritis].

PubMed

Abou-Haila, A; Hadjiisky, P; Roland, J; Orcel, L

1978-04-01

The parietal reaction after placing a cuff of polyethylene around the femoral artery has been studied in 18 (2,5 - 3 months old) male rabbits by using histologic, histochemical (4 macromolecular substances) and histoenzymatic techniques (16 enzymatic activities). Studies were performed on the 1st, 3rd, 5th, 15th and 21st day, and every 15 days during the 3 months of the experiment. This process induced rapidly in each animal a parietal reaction with adventitial oedema (1st day), hypoxia of the media (1st -5th day), cytoenzymatic activation followed by a cellular transformation and proliferation of the intima-media, that forms a diffuse intimal thickening (adaptation). Most cells of the thickening were, by their enzymatic activities, quite comparable to immature smooth muscle cells, which probably emigrated from the media: intense LDH, NADH2 - TR; moderate G6P-DH, SDH, NADPH2 - TR, alpha-GP-DH, ATP/ase; weak ICHD, beta-HB-DH. Moreover, some reactions (accentuation of beta-Glu/ase, UDGP-DH, Glu-DH, 5'N/ase) besides suggested the active participation of the cells in the production of extracellular conjonctive constituents, because the histochemical studies revealed the presence of metachromatic glycosamino-glycanes and positive APS substances during the edification of the diffuse intimal thickening. In advanced thickening, an histoenzymatic duality was observed, that might prove the double origin of the thickening cells: some superficial cells had the enzymatic characteristics of endothelial cells (increased activity of aerobic oxydoreductases). At every stage of the study, the thickening cells differed from the atherocytes by a lack of lipids in their cytoplasm.

Neural crest apoptosis and the establishment of craniofacial pattern: an honorable death.

PubMed

Graham, A; Koentges, G; Lumsden, A

1996-01-01

During development of the vertebrate head neural crest cells emigrate from the hindbrain and populate the branchial arches, giving rise to distinct skeletal elements and muscle connective tissues in each arch. The production of neural crest from the hindbrain is discontinuous and crest cells destined for different arches, carrying different positional cues, are separated by regions of apoptosis centered on rhombomeres (r) 3 and r5. This cell death program is under the interactive control of the neighboring hindbrain segments. Both r3 and r5 produce large numbers of crest cells when freed from their flanking rhombomere, but when conjoined with their neighbor the cell death program is restored. Two key components of this program are Bmp 4 and msx-2, both of which are expressed in the apoptotic foci of r3 and r5 and which are also regulated by neighbor interactions. Importantly, the addition of recombinant Bmp 4 to isolated cultures of r3 and r5 induces the expression of Bmp 4 and msx-2 and restores the cell death program. This early neural crest segregation is maintained during development and it has profound effects upon the final craniofacial pattern. Even though crest cells from different axial origins will contribute to compound skeletal elements, these distinct populations do not intermingle. Furthermore head muscle connective tissues are exclusively anchored to skeletal domains arising from neural crest from the same axial level. Thus the discontinuous production of neural crest sculpts the crest into nonmixing streams and consequently ensures the fidelity of patterning.

Activation of neurokinin-1 receptors during ozone inhalation contributes to epithelial injury and repair.

PubMed

Oslund, Karen L; Hyde, Dallas M; Putney, Leialoha F; Alfaro, Mario F; Walby, William F; Tyler, Nancy K; Schelegle, Edward S

2008-09-01

We investigated the importance of neurokinin (NK)-1 receptors in epithelial injury and repair and neutrophil function. Conscious Wistar rats were exposed to 1 ppm ozone or filtered air for 8 hours, followed by an 8-hour postexposure period. Before exposure, we administered either the NK-1 receptor antagonist, SR140333, or saline as a control. Ethidium homodimer was instilled into lungs as a marker of necrotic airway epithelial cells. After fixation, whole mounts of airway dissected lung lobes were immunostained for 5-bromo-2'-deoxyuridine, a marker of epithelial proliferation. Both ethidium homodimer and 5-bromo-2'-deoxyuridine-positive epithelial cells were quantified in specific airway generations. Rats treated with the NK-1 receptor antagonist had significantly reduced epithelial injury and epithelial proliferation compared with control rats. Sections of terminal bronchioles showed no significant difference in the number of neutrophils in airways between groups. In addition, staining ozone-exposed lung sections for active caspase 3 showed no apoptotic cells, but ethidium-positive cells colocalized with the orphan nuclear receptor, Nur77, a marker of nonapoptotic, programmed cell death mediated by the NK-1 receptor. An immortalized human airway epithelial cell line, human bronchial epithelial-1, showed no significant difference in the number of oxidant stress-positive cells during exposure to hydrogen peroxide and a range of SR140333 doses, demonstrating no antioxidant effect of the receptor antagonist. We conclude that activation of the NK-1 receptor during acute ozone inhalation contributes to epithelial injury and subsequent epithelial proliferation, a critical component of repair, but does not influence neutrophil emigration into airways.

[Migrations and economic and social change in Egypt].

PubMed

Ged, A

1985-01-01

The inexistence in the Arab world of institutions to facilitate development led Egypt to adopt the infitah, a policy of economic opening which is not a voluntarist economic strategy but rather is intended to create a climate favorable to a more capitalistic orientation for individuals with access to petroleum income. Egypt's gross national product grew by 4.6%/year in the dozen years through 1965, but thereafter growth was sluggish or even negative. After 1967 the choices of the dominant economic classes were oriented toward liberalism, and the arrival of Sadat allowed this orientation to prevail even before the infitah. The various measures of the infitah were designed to promote investment, reactivate the private sector, and reorganize the public sector. Most of the specific projects approved through 1978 were in the tertiary sector, they did little to stimulate further development, and the total number of jobs created was relatively insignificant. The transformation of the Egyptian economy is due not so much to the infitah as to 4 other elements: oil, income from the Suez canal, tourism, and emigration. At present petroleum represents 30% of Egypt's exports, the Suez canal will probably bring in $1.5 billion annually in coming years, and tourism brought in $1 billion in 1984, but in terms of economic and social impact on the total population emigration is much more important. The number of emigrants increased from 100,000 in 1973 to over 3 million in 1984 and the extent of their remittances increased from $184 million in 1973 to nearly $4 billion at present. Serious shortages of skilled and unskilled labor have been created by the departure of 10-15% of the overall labor force and a higher proportion for some skilled professions. The number of workers in construction more than doubled from 1971-79, while 10% of the agricultural labor force departed. Agricultural wages increased by an average of 7.1% in these years as agricultural workers were attracted to the higher wages of construction. However, the actual levels of agricultural wages were very low at outset. Differences between Egyptian wages and those paid in the Gulf states became so significant that they disrupted the prevailing norms and hierarchies of remuneration. The development of migration thus represents an individual response to 2 types of problems: the incapacity of the Egyptian state to develop an economy that creates employment, and the development of methods to allow each Arab state to benefit from petroleum income. But the future course of migration to the Gulf states is not known, and whether the improvements already observed in the lives of rural Egyptians can be sustained over the long term is a vital question.

The Intellectuals' Migration: The Emigre's Conquest of American Academia.

ERIC Educational Resources Information Center

Heilbut, Anthony

1984-01-01

A flow of scientists, artists, filmmakers, poets, historians, novelists, and philosophers driven into exile by Hitler were destined to change the tone of American culture. Some of the most productive work was done in academic settings specifically set up for refugee scholars. (MLW)

The Prairie Novel and the European Immigrant: New Perspectives for the Geography Classroom.

ERIC Educational Resources Information Center

Wyckoff, William

1979-01-01

Discusses using novels set in North and South Dakota and Nebraska for geography instruction. Novels examined are: "The Emigrants" (Bojer), "Giants in the Earth" (Rolvaag), "Spring Came on Forever" (Aldrich), "Take All to Nebraska" (Winther), and "My Antonia" (Cather). (KC)

Environmental and Ethical Aspects of International Migration.

ERIC Educational Resources Information Center

Abernethy, Virginia

1996-01-01

Well-intentioned U.S. immigration policy has two ill effects in that it encourages the belief that emigration can relieve overpopulation in third-world countries, maintaining high fertility rates, and it results in U.S. domestic population growth that threatens employment opportunities and the environment. (SLD)

INTEGRATION OF STATISTICS, REMOTE SENSING AND EXISTING DATA TO LOCATE CHANGES IN LAND RESOURCES

EPA Science Inventory

Stability of a nation is dependent on the availability of natural resources. When land is degraded and natural resources become limited, socioeconomic status declines and emigration increases in developing countries. Natural resource utilization without proper management may re...

Butterfly survival on an isolated island by improved grip

PubMed Central

Duplouy, Anne; Hanski, Ilkka

2013-01-01

On small isolated islands, natural selection is expected to reduce the dispersal capacity of organisms, as short distances do not require a high rate of dispersal, which might lead to accidental emigration from the population. In addition, individuals foregoing the high cost of maintaining flight capacity may instead allocate resources to other functions. However, in butterflies and many other insects, flight is necessary not only for dispersal but also for most other activities. A weakly flying individual would probably do worse and have an elevated rather than reduced probability of accidental emigration. Here, we report results consistent with the hypothesis that a butterfly population on an isolated island, instead of having lost its flight capacity, has evolved better grip to resist the force of wind and to avoid being blown off the island. Our study suggests that local adaptation has occurred in this population in spite of its very small size (Ne ∼ 100), complete isolation, low genetic variation and high genetic load. PMID:23445946

[Max Isserlin, Kantian orientation at Königsberg, psychotherapist with Kraepelin, founder of child psychiatry at Munich, emigrant to Britain].

PubMed

Peters, U H

2002-01-01

This account of the life and work of Max Isserlin (1879 - 1941) wants to be a reminder of a German-Jewish fate next to Kraepelin and as a forced emigrant. Immediately after his studies at Königsberg Isserlin in 1903 came to Kraepelin at Heidelberg, later he followed him to Munich. All his life he kept a Kantian orientation and defended Kraepelin's positions out of this background. Kraepelin entrusted to him all of psychotherapy, theory and practice, which Isserlin for at least 18 years gave courses of in Kraepelin's department. His textbook of psychotherapy thus transmissions Kraepelins convictions about this topic also. During World War I Isserlin was the head of a field-hospital for brain damaged soldiers and continued working this way after the end of the war. Finally he became the founder of child psychiatry in Munich, until he was forced to leave Germany for Britain with a heavy heart.

The association between acculturation and health insurance coverage for immigrant children from socioeconomically disadvantaged regions of origin.

PubMed

Hernandez, Daphne C; Kimbro, Rachel Tolbert

2013-06-01

Among immigrant children whose parents have historically had lower education, the study explored which immigrant children were most likely to have coverage based on maternal region of origin. The direct and indirect relationship of acculturation on immigrant children's coverage was also assessed. A subsample of US-born children with foreign-born mothers from the Early Childhood Longitudinal Survey-Kindergarten Cohort was analyzed using multinomial logistic regressions (n = 1,686). Children whose mothers emigrated from the Caribbean or Indochina had greater odds of being insured compared to children whose mothers emigrated from Mexico. Moreover, Latin American children did not statistically differ from Mexican children in being uninsured. Maternal citizenship was positively associated with children's coverage; while living in a household with a mother who migrated as a child was negatively associated with private insurance. To increase immigrant children's coverage, Latin American and Mexican families may benefit from additional financial assistance, rather than cultural assistance.

Manatees in the Gulf of Mexico

USGS Publications Warehouse

Bonde, Robert K.; Lefebvre, Lynn W.

2001-01-01

The endangered Florida manatee (Trichechus manatus latirostris) inhabits rivers and estuaries along both coasts of Florida and, to a lesser extent, adjacent states (Figure 1). Since 1990, documented sightings of manatees outside of Florida have been increasing. This increase in sightings probably represents northward shifts in manatee distribution made possible by man-made sources of warm water (i.e., industrial effluents), as well as a decade of relatively warm winters. The most likely source of emigrants on the Gulf coast is the population of manatees that overwinter in the headwaters of the Crystal and Homosassa Rivers, Citrus County, FL. This group of manatees has undergone a steady increase in numbers, (approximately 7% per year from 1977-1991; Eberhardt and O’Shea 1995). Some emigrants may also come from the Tampa-Ft. Myers region, where human impacts on habitat are greater. Manatees are intelligent, long-lived mammals that appear to adapt readily to new environments and situations. However, manatees have relatively low metabolic rates, and cold winter temperatures restrict their northern distribution.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monnett, C.; Rotterman, L.M.

Ninety-six adult female sea otters and 64 weanling sea otters were instrumented with implanted radio-transmitters in Prince William Sound during 1989-1990 and monitored until November, 1991. Observations of the movements of adult female and weanling sea otters in prince William Sound indicated no tendency for individuals to emigrate from, or immigrate to, the area affected by oil spilled from the Exxon Valdez. This finding indicates that the study groups of sea otters categorized as `western Prince William Sound oil-spill treatment` otters and `eastern Prince William Sound control` otters are indeed distinct groups of individuals. No tendency was observed for recentlymore » weaned sea otters to exhibit a preference for habitat units based on the likelihood that they would encounter spilled oil therein. Finally, data reported suggest that the recovery of the sea otter population in the oil spill affected region of Prince William Sound will likely be a direct function of the rates of survival and reproduction of the sea otters in the affected habitat with little or no influence from emigration or immigration.« less

Stochastic Forecasting of Labor Supply and Population: An Integrated Model.

PubMed

Fuchs, Johann; Söhnlein, Doris; Weber, Brigitte; Weber, Enzo

2018-01-01

This paper presents a stochastic model to forecast the German population and labor supply until 2060. Within a cohort-component approach, our population forecast applies principal components analysis to birth, mortality, emigration, and immigration rates, which allows for the reduction of dimensionality and accounts for correlation of the rates. Labor force participation rates are estimated by means of an econometric time series approach. All time series are forecast by stochastic simulation using the bootstrap method. As our model also distinguishes between German and foreign nationals, different developments in fertility, migration, and labor participation could be predicted. The results show that even rising birth rates and high levels of immigration cannot break the basic demographic trend in the long run. An important finding from an endogenous modeling of emigration rates is that high net migration in the long run will be difficult to achieve. Our stochastic perspective suggests therefore a high probability of substantially decreasing the labor supply in Germany.

Household Migration, Social Support, and Psychosocial Health: The Perspective from Migrant-Sending Areas

PubMed Central

Lu, Yao

2011-01-01

An extensive literature demonstrates various negative health consequences of family disruption in Western societies, which is largely due to marital dissolution. In developing settings, family disruption commonly arises in the context of labor out-migration. However, studies on household emigration often focus on the economic benefits from remittances, overlooking emigration as a source of stress and loss of social support. This research examines the psychosocial consequences of internal out-migration using longitudinal survey data collected in Indonesia between 1993 and 2007. Results demonstrate considerable psychosocial costs of out-migration, with adults left behind by migrants more susceptible to stress-related health impairments such as hypertension and to psychological distress such as depressive symptoms. These findings largely hold when specific relations are investigated, including spouses left behind and parents left behind by adult children. This study also finds some support for the stress-buffering role of social support from extended families and the differential psychosocial processes for men and women. PMID:22169626

Atopic dermatitis induces the expansion of thymus-derived regulatory T cells exhibiting a Th2-like phenotype in mice.

PubMed

Moosbrugger-Martinz, Verena; Tripp, Christoph H; Clausen, Björn E; Schmuth, Matthias; Dubrac, Sandrine

2016-05-01

Atopic dermatitis (AD) is a widespread inflammatory skin disease with an early onset, characterized by pruritus, eczematous lesions and skin dryness. This chronic relapsing disease is believed to be primarily a result of a defective epidermal barrier function associated with genetic susceptibility, immune hyper-responsiveness of the skin and environmental factors. Although the important role of abnormal immune reactivity in the pathogenesis of AD is widely accepted, the role of regulatory T cells (Tregs) remains elusive. We found that the Treg population is expanded in a mouse model of AD, i.e. mice topically treated with vitamin D3 (VitD). Moreover, mice with AD-like symptoms exhibit increased inducible T-cell costimulator (ICOS)-, cytotoxic T-lymphocyte antigen-4 (CTLA-4)- and Glycoprotein-A repetitions predominant receptor (GARP)-expressing Tregs in skin-draining lymph nodes. Importantly, the differentiation of Tregs into thymus-derived Tregs is favoured in our mouse model of AD. Emigrated skin-derived dendritic cells are required for Treg induction and Langerhans cells are responsible for the biased expansion of thymus-derived Tregs . Intriguingly, thymus-derived Tregs isolated from mice with AD-like symptoms exhibit a Th2 cytokine profile. Thus, AD might favour the expansion of pathogenic Tregs able to produce Th2 cytokines and to promote the disease instead of alleviating symptoms. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Major features of immunesenescence, including reduced thymic output, are ameliorated by high levels of physical activity in adulthood.

PubMed

Duggal, Niharika Arora; Pollock, Ross D; Lazarus, Norman R; Harridge, Stephen; Lord, Janet M

2018-04-01

It is widely accepted that aging is accompanied by remodelling of the immune system including thymic atrophy and increased frequency of senescent T cells, leading to immune compromise. However, physical activity, which influences immunity but declines dramatically with age, is not considered in this literature. We assessed immune profiles in 125 adults (55-79 years) who had maintained a high level of physical activity (cycling) for much of their adult lives, 75 age-matched older adults and 55 young adults not involved in regular exercise. The frequency of naïve T cells and recent thymic emigrants (RTE) were both higher in cyclists compared with inactive elders, and RTE frequency in cyclists was no different to young adults. Compared with their less active counterparts, the cyclists had significantly higher serum levels of the thymoprotective cytokine IL-7 and lower IL-6, which promotes thymic atrophy. Cyclists also showed additional evidence of reduced immunesenescence, namely lower Th17 polarization and higher B regulatory cell frequency than inactive elders. Physical activity did not protect against all aspects of immunesenescence: CD28 -ve CD57 +ve senescent CD8 T-cell frequency did not differ between cyclists and inactive elders. We conclude that many features of immunesenescence may be driven by reduced physical activity with age. © 2018 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Lymph node and circulating T cell characteristics are strongly correlated in end-stage renal disease patients, but highly differentiated T cells reside within the circulation.

PubMed

Dedeoglu, B; de Weerd, A E; Huang, L; Langerak, A W; Dor, F J; Klepper, M; Verschoor, W; Reijerkerk, D; Baan, C C; Litjens, N H R; Betjes, M G H

2017-05-01

Ageing is associated with changes in the peripheral T cell immune system, which can be influenced significantly by latent cytomegalovirus (CMV) infection. To what extent changes in circulating T cell populations correlate with T cell composition of the lymph node (LN) is unclear, but is crucial for a comprehensive understanding of the T cell system. T cells from peripheral blood (PB) and LN of end-stage renal disease patients were analysed for frequency of recent thymic emigrants using CD31 expression and T cell receptor excision circle content, relative telomere length and expression of differentiation markers. Compared with PB, LN contained relatively more CD4 + than CD8 + T cells (P < 0·001). The percentage of naive and central memory CD4 + and CD8 + T cells and thymic output parameters showed a strong linear correlation between PB and LN. Highly differentiated CD28 null T cells, being CD27 - , CD57 + or programmed death 1 (PD-1 + ), were found almost exclusively in the circulation but not in LN. An age-related decline in naive CD4 + and CD8 + T cell frequency was observed (P = 0·035 and P = 0·002, respectively) within LN, concomitant with an increase in central memory CD8 + T cells (P = 0·033). Latent CMV infection increased dramatically the frequency of circulating terminally differentiated T cells, but did not alter T cell composition and ageing parameters of LN significantly. Overall T cell composition and measures of thymic function in PB and LN are correlated strongly. However, highly differentiated CD28 null T cells, which may comprise a large part of circulating T cells in CMV-seropositive individuals, are found almost exclusively within the circulation. © 2017 British Society for Immunology.

Minneapolis Multi-Ethnic Curriculum Project--Migration Unit.

ERIC Educational Resources Information Center

Minneapolis Public Schools, Minn. Dept. of Intergroup Education.

The student booklet presents short chapters illustrating the migration unit of the Minneapolis Multi-Ethnic Curriculum Project for secondary schools. Sixteen brief chapters describe migration, immigration, and emigration in the United States. The first six chapters offer first person accounts of immigrants from Norway, Korea, Egypt, Hitler's…

From Immigrants to Ethnics: The Italian Americans.

ERIC Educational Resources Information Center

Nelli, Humbert S.

A sociological, political, and cultural history of Italians in America, this book's chapters discuss (1) Italian explorers, intellectuals, and artisans who participated in the settlement and establishment of the United States; (2) socioeconomic conditions in nineteenth century Italy that led to mass emigration; (3) the distribution of Italian…

Development of a Systemwide Predator Control Program Section I : Northern Squawfish Management Program Implementation, 1995 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, Franklin R.

1997-04-01

Results from the fifth year of a basinwide program to harvest northern squawfish (Ptychocheilus oregonensis) in an effort to reduce mortality due to northern squawfish predation on juvenile salmonids during their emigration from natal streams to the ocean.

Confronting School: Immigrant Families, Hope, Education

ERIC Educational Resources Information Center

Amigó, María Florencia

2017-01-01

While children remain at the center of families' decisions to emigrate, the global contexts and technologies that allow diasporas to remain connected to their cultures have influenced families' aspirations in relation to their children's education. This article presents data from a qualitative study on how immigrant families negotiate the…

Russian Higher Education in China

ERIC Educational Resources Information Center

Khisamutdinov, A. A.

2016-01-01

In the first half of the twentieth century, Russian emigrants in China established a network of higher education institutions based on the prerevolutionary Russian educational system. By referring to memoirs and publications in the periodical press, the author traces the history of the most significant educational establishments: Harbin School of…

Mexico’s Troublesome Triangle: Poverty, Education, and Emigration

DTIC Science & Technology

2011-10-28

classroom technology, and infrastructure improvements are now clearly seen as impediments to students’ abilities. This is especially obvious in the results...country. There are various factors that a child may be dealing with when they move – and it can be especially disorienting when crossing between

James Craig Watson (1838-1880)

NASA Astrophysics Data System (ADS)

Broughton, Peter

1996-04-01

Canadians feel a bittersweet pride when young people leave to make their fame and fortune in the United States. The life of the eminent nineteenth century astronomer, J. C. Watson, is another example from history that our brightest and best emigrate when educational and career opportunities are lacking at home.

Semiochemical lures reduce emigration and enhance pest control services in open-field predator augmentation

USDA-ARS?s Scientific Manuscript database

Augmentation biocontrol is a commercially viable pest management tactic in enclosed glasshouse environments, but is far less effective in open-field agriculture where newly released enemies rapidly disperse from release sites. We tested the potential for behavior-modifying semiochemicals to increase...

22 CFR 99.1 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Definitions. 99.1 Section 99.1 Foreign Relations DEPARTMENT OF STATE LEGAL AND RELATED SERVICES REPORTING ON CONVENTION AND NON-CONVENTION ADOPTIONS OF EMIGRATING CHILDREN § 99.1 Definitions. As used in this part, the term: (a) Convention means...

Greeks in America; Staff Development Module.

ERIC Educational Resources Information Center

Lereah, Lucy; And Others

This module lists eight staff development objectives pertaining to various aspects of Greek-American culture. Topics dealt with include Greek emigration and immigration, Greek vocabulary, contributions made by prominent Greek-Americans, Greek family life and the changing role of family members, Greek values, and the growth of Atlanta's Greek…

IL-7-Induced Proliferation of Human Naive CD4 T-Cells Relies on Continued Thymic Activity.

PubMed

Silva, Susana L; Albuquerque, Adriana S; Matoso, Paula; Charmeteau-de-Muylder, Bénédicte; Cheynier, Rémi; Ligeiro, Dário; Abecasis, Miguel; Anjos, Rui; Barata, João T; Victorino, Rui M M; Sousa, Ana E

2017-01-01

Naive CD4 T-cell maintenance is critical for immune competence. We investigated here the fine-tuning of homeostatic mechanisms of the naive compartment to counteract the loss of de novo CD4 T-cell generation. Adults thymectomized in early childhood during corrective cardiac surgery were grouped based on presence or absence of thymopoiesis and compared with age-matched controls. We found that the preservation of the CD31 - subset was independent of the thymus and that its size is tightly controlled by peripheral mechanisms, including prolonged cell survival as attested by Bcl-2 levels. Conversely, a significant contraction of the CD31 + naive subset was observed in the absence of thymic activity. This was associated with impaired responses of purified naive CD4 T-cells to IL-7, namely, in vitro proliferation and upregulation of CD31 expression, which likely potentiated the decline in recent thymic emigrants. Additionally, we found no apparent constraint in the differentiation of naive cells into the memory compartment in individuals completely lacking thymic activity despite upregulation of DUSP6 , a phosphatase associated with increased TCR threshold. Of note, thymectomized individuals featuring some degree of thymopoiesis were able to preserve the size and diversity of the naive CD4 compartment, further arguing against complete thymectomy in infancy. Overall, our data suggest that robust peripheral mechanisms ensure the homeostasis of CD31 - naive CD4 pool and point to the requirement of continuous thymic activity to the maintenance of IL-7-driven homeostatic proliferation of CD31 + naive CD4 T-cells, which is essential to secure T-cell diversity throughout life.

Beta-Actin Is Required for Proper Mouse Neural Crest Ontogeny

PubMed Central

Tondeleir, Davina; Noelanders, Rivka; Bakkali, Karima; Ampe, Christophe

2014-01-01

The mouse genome consists of six functional actin genes of which the expression patterns are temporally and spatially regulated during development and in the adult organism. Deletion of beta-actin in mouse is lethal during embryonic development, although there is compensatory expression of other actin isoforms. This suggests different isoform specific functions and, more in particular, an important function for beta-actin during early mammalian development. We here report a role for beta-actin during neural crest ontogeny. Although beta-actin null neural crest cells show expression of neural crest markers, less cells delaminate and their migration arrests shortly after. These phenotypes were associated with elevated apoptosis levels in neural crest cells, whereas proliferation levels were unchanged. Specifically the pre-migratory neural crest cells displayed higher levels of apoptosis, suggesting increased apoptosis in the neural tube accounts for the decreased amount of migrating neural crest cells seen in the beta-actin null embryos. These cells additionally displayed a lack of membrane bound N-cadherin and dramatic decrease in cadherin-11 expression which was more pronounced in the pre-migratory neural crest population, potentially indicating linkage between the cadherin-11 expression and apoptosis. By inhibiting ROCK ex vivo, the knockout neural crest cells regained migratory capacity and cadherin-11 expression was upregulated. We conclude that the presence of beta-actin is vital for survival, specifically of pre-migratory neural crest cells, their proper emigration from the neural tube and their subsequent migration. Furthermore, the absence of beta-actin affects cadherin-11 and N-cadherin function, which could partly be alleviated by ROCK inhibition, situating the Rho-ROCK signaling in a feedback loop with cadherin-11. PMID:24409333

Antiretroviral therapy suppressed participants with low CD4+ T-cell counts segregate according to opposite immunological phenotypes

PubMed Central

Pérez-Santiago, Josué; Ouchi, Dan; Urrea, Victor; Carrillo, Jorge; Cabrera, Cecilia; Villà-Freixa, Jordi; Puig, Jordi; Paredes, Roger; Negredo, Eugènia; Clotet, Bonaventura; Massanella, Marta; Blanco, Julià

2016-01-01

Background: The failure to increase CD4+ T-cell counts in some antiretroviral therapy suppressed participants (immunodiscordance) has been related to perturbed CD4+ T-cell homeostasis and impacts clinical evolution. Methods: We evaluated different definitions of immunodiscordance based on CD4+ T-cell counts (cutoff) or CD4+ T-cell increases from nadir value (ΔCD4) using supervised random forest classification of 74 immunological and clinical variables from 196 antiretroviral therapy suppressed individuals. Unsupervised clustering was performed using relevant variables identified in the supervised approach from 191 individuals. Results: Cutoff definition of CD4+ cell count 400 cells/μl performed better than any other definition in segregating immunoconcordant and immunodiscordant individuals (85% accuracy), using markers of activation, nadir and death of CD4+ T cells. Unsupervised clustering of relevant variables using this definition revealed large heterogeneity between immunodiscordant individuals and segregated participants into three distinct subgroups with distinct production, programmed cell-death protein-1 (PD-1) expression, activation and death of T cells. Surprisingly, a nonnegligible number of immunodiscordant participants (22%) showed high frequency of recent thymic emigrants and low CD4+ T-cell activation and death, very similar to immunoconcordant participants. Notably, human leukocyte antigen - antigen D related (HLA-DR) PD-1 and CD45RA expression in CD4+ T cells allowed reproducing subgroup segregation (81.4% accuracy). Despite sharp immunological differences, similar and persistently low CD4+ values were maintained in these participants over time. Conclusion: A cutoff value of CD4+ T-cell count 400 cells/μl classified better immunodiscordant and immunoconcordant individuals than any ΔCD4 classification. Immunodiscordance may present several, even opposite, immunological patterns that are identified by a simple immunological follow-up. Subgroup classification may help clinicians to delineate diverse approaches that may be needed to boost CD4+ T-cell recovery. PMID:27427875

Factors Influencing Curricular Reform; An Irish Perspective

ERIC Educational Resources Information Center

Ferris, Helena; Joyce, Pauline

2015-01-01

There are various influences and obstacles when planning an educational curriculum. The imprint of globalisation on the landscape of Irish medicine highlights the importance of delivering a diverse curriculum with international dimensions so that knowledge and skills can transfer across borders. It is also clear that medical emigration has a…

Tongue-Tied in Singapore: A Language Policy for Tamil?

ERIC Educational Resources Information Center

Schiffman, Harold F.

2003-01-01

Discusses the Tamil language situation in Singapore, which lends itself ideally to the study of minority-language maintenance. Examines attempts to maintain Tamil, a highly diglossic language in emigration and concludes that the well-meaning bilingual education system actually produces a situation of subtractive bilingualism. (Author/VWL)

Reviving a Community, Modernizing an Industry: Ireland's Furniture College.

ERIC Educational Resources Information Center

Regional Technology Strategies, Inc., Carrboro, NC.

Connemara, a rural region in Ireland, is characterized by high unemployment, high emigration, poor infrastructure, inadequate public services, and a low rate of transfer to third-level education. To address the situation, the Galway-Mayo Institute of Technology (GMIT), joined forces with Connemara West (a community-owned development organization…

Afrikaans Language Maintenance in Australia

ERIC Educational Resources Information Center

Hatoss, Aniko; Starks, Donna; van Rensburg, Henriette Janse

2011-01-01

Changes in the political climate in the home country have resulted in the emigration of South Africans to English speaking countries such as Britain, Canada, Australia and New Zealand. Despite the scale of movement of the South African population, language maintenance in these diasporic contexts has received little consideration. This paper…

The Story Road to Literacy

ERIC Educational Resources Information Center

Roth, Rita

2005-01-01

This book grew out of research conducted during a sabbatical as Associate Professor of Education at Rockhurst University in Kansas City. The study focused on collecting folktales from recently emigrated school children in order to build a curriculum to support the growth of English literacy in these students and their native English-speaking…

22 CFR 96.43 - Case tracking, data management, and reporting.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) Wherever possible, for each dissolution of a Convention adoption, information and reports on the dissolution, including information on: (i) The Convention country from which the child emigrated; (ii) The... for adoption; (v) The reason(s) for and resolution(s) of the dissolution of the adoption, to the...

Education and Emigration: The Case of the Iranian-American Community

ERIC Educational Resources Information Center

Mossayeb, Sina M.; Shirazi, Roozbeh

2006-01-01

This paper explores the plausibility of a hypothesis that puts forth perceived educational opportunity as a significant pull factor influencing Iranians' decisions to immigrate to the United States. Drawing on various literatures, including research on educational policy in Iran, government policy papers, and figures from recent studies and census…

Unbiased survival estimates and evidence for skipped breeding opportunities in females

USGS Publications Warehouse

Muths, Erin L.; Scherer, Rick D.; Lambert, Brad A.

2010-01-01

5. Establishing the occurrence of temporary emigration not only reduces bias in estimates of survival probabilities but also provides information about expected breeding attempts by females, a critical element in understanding the ecology of an organism and the impacts of outside stressors and conservation actions.

31 CFR 515.557 - Accounts of Cuban partnerships.

Code of Federal Regulations, 2010 CFR

2010-07-01

... are issued unblocking partnerships established under the laws of Cuba as follows: (a) Where all of the general partners and limited partners, if any, have emigrated from Cuba and have established residence in...) Where one or more partners, whether general or limited, is still in Cuba (or elsewhere but still blocked...

Migration, Aid and Trade: Policy Coherence for Development. Policy Brief No. 28

ERIC Educational Resources Information Center

Dayton-Johnson, Jeff; Katseli, Louka T.

2006-01-01

Many Organisation for Economic Cooperation and Development (OECD) countries recruit internationally skilled workers for their health, education, or public administration sectors and the subsequent emigration of such workers can cause critical shortages in developing countries, even as these countries receive substantial aid from those same OECD…

The Soviet Union: Population Trends and Dilemmas.

ERIC Educational Resources Information Center

Feshbach, Murray

1982-01-01

Recent trends and differentials among the Soviet Union's 15 republics and major nationalities are reviewed, focusing on fertility, mortality and urbanization, the prospect for labor supplies and military manpower, emigration, and projected population growth to 2000. Estimated at 270 million as of mid-1982, the Soviet population is currently…

The Ethno-Cultural Concept of Classical Eurasianism

ERIC Educational Resources Information Center

Ivanov, Andrey V.; Fotieva, Irina V.; Shishin, Michail Yu.; Belokurovac, Sofja M.

2016-01-01

The purpose of this study is to analyze of Eurasianism, which began during the Russian scientific and philosophical emigration and has generated sharp discussion over the last century. Within the framework of Eurasianism, extensive research has been conducted on a wide range of interrelated topics, much of whose theoretical and practical…

31 CFR 500.558 - Accounts of blocked partnerships.

Code of Federal Regulations, 2010 CFR

2010-07-01

... are issued unblocking partnerships established under the laws of North Korea, North Viet-Nam, Cambodia..., have emigrated from North Korea, North Viet-Nam, Cambodia, or South Viet-Nam and have established... located. (b) Where one or more partners, whether general or limited, is in North Korea, North Viet-Nam...

Leading Multiethnic Schools: A New Understanding of Muslim Youth Identity

ERIC Educational Resources Information Center

Shah, Saeeda

2006-01-01

In the context of emigration, immigration, international mobility and globalization, the management contexts of education sites are undergoing deep and sensitive changes making challenging demands on educational leaders. Multiethnic/multicultural schools are emerging as a long-term phenomenon in countries such as Britain against the backdrop of…

Passing through - reasons why migrant doctors in Ireland plan to stay, return home or migrate onwards to new destination countries.

PubMed

Brugha, Ruairí; McAleese, Sara; Dicker, Pat; Tyrrell, Ella; Thomas, Steve; Normand, Charles; Humphries, Niamh

2016-06-30

International recruitment is a common strategy used by high-income countries to meet their medical workforce needs. Ireland, despite training sufficient doctors to meet its internal demand, continues to be heavily dependent on foreign-trained doctors, many of whom may migrate onwards to new destination countries. A cross-sectional study was conducted to measure and analyse the factors associated with the migratory intentions of foreign doctors in Ireland. A total of 366 non-European nationals registered as medical doctors in Ireland completed an online survey assessing their reasons for migrating to Ireland, their experiences whilst working and living in Ireland, and their future plans. Factors associated with future plans - whether to remain in Ireland, return home or migrate to a new destination country - were tested by bivariate and multivariate analyses, including discriminant analysis. Of the 345 foreign doctors who responded to the question regarding their future plans, 16 % of whom were Irish-trained, 30 % planned to remain in Ireland, 23 % planned to return home and 47 % to migrate onwards. Country of origin, personal and professional reasons for migrating, experiences of training and supervision, opportunities for career progression, type of employment contract, citizenship status, and satisfaction with life in Ireland were all factors statistically significantly associated with the three migratory outcomes. Reported plans may not result in enacted emigration. However, the findings support a growing body of evidence highlighting dissatisfaction with current career opportunities, contributing to the emigration of Irish doctors and onward migration of foreign doctors. Implementation of the WHO Global Code, which requires member states to train and retain their own health workforce, could also help reduce onward migration of foreign doctors to new destination countries. Ireland has initiated the provision of tailored postgraduate training to doctors from Pakistan, enabling these doctors to return home with improved skills of benefit to the source country.

Activation of Neurokinin-1 Receptors during Ozone Inhalation Contributes to Epithelial Injury and Repair

PubMed Central

Oslund, Karen L.; Hyde, Dallas M.; Putney, Leialoha F.; Alfaro, Mario F.; Walby, William F.; Tyler, Nancy K.; Schelegle, Edward S.

2008-01-01

We investigated the importance of neurokinin (NK)-1 receptors in epithelial injury and repair and neutrophil function. Conscious Wistar rats were exposed to 1 ppm ozone or filtered air for 8 hours, followed by an 8-hour postexposure period. Before exposure, we administered either the NK-1 receptor antagonist, SR140333, or saline as a control. Ethidium homodimer was instilled into lungs as a marker of necrotic airway epithelial cells. After fixation, whole mounts of airway dissected lung lobes were immunostained for 5-bromo-2′-deoxyuridine, a marker of epithelial proliferation. Both ethidium homodimer and 5-bromo-2′-deoxyuridine-positive epithelial cells were quantified in specific airway generations. Rats treated with the NK-1 receptor antagonist had significantly reduced epithelial injury and epithelial proliferation compared with control rats. Sections of terminal bronchioles showed no significant difference in the number of neutrophils in airways between groups. In addition, staining ozone-exposed lung sections for active caspase 3 showed no apoptotic cells, but ethidium-positive cells colocalized with the orphan nuclear receptor, Nur77, a marker of nonapoptotic, programmed cell death mediated by the NK-1 receptor. An immortalized human airway epithelial cell line, human bronchial epithelial-1, showed no significant difference in the number of oxidant stress–positive cells during exposure to hydrogen peroxide and a range of SR140333 doses, demonstrating no antioxidant effect of the receptor antagonist. We conclude that activation of the NK-1 receptor during acute ozone inhalation contributes to epithelial injury and subsequent epithelial proliferation, a critical component of repair, but does not influence neutrophil emigration into airways. PMID:18390473

Genetic affinities of the Siddis of South India: an emigrant population of East Africa.

PubMed

Gauniyal, Mansi; Chahal, S M S; Kshatriya, Gautam K

2008-06-01

Historical records indicate that the Portuguese brought the African Siddis to Goa, India, as slaves about 500 years ago. Subsequently, the Siddis moved into the interior regions of the state of Karnataka, India, and have remained there ever since. Over time the Siddis have experienced considerable cultural changes because of their proximity to neighboring population groups. To understand the biological consequences of these changes, we studied the Siddis to determine the extent of genetic variation and the contributions from the African, European, and Indian ancestral populations. In the present study we typed the Siddis for 20 polymorphic serological, red cell, and Alu insertion-deletion loci. The overall pattern of phenotype (and genotype) distribution is in accordance with Hardy-Weinberg expectations. Considering the ethnohistorical records and the availability of secondary-source genetic data, we used two data sets in the analysis: one comprising eight serological and red cell enzyme markers with eight population groups and another comprising six Alu insertion-deletion markers with seven tribal groups of South India. The dendrograms generated from these two data sets on the basis of genetic distance analysis between the selected populations of African, European, and Indian descent reveals that the Siddis are closer to the Africans than they are to the South Indian populations. Genetic admixture analysis using a dihybrid model (19 loci) and a trihybrid model (10 loci and 8 loci) shows that the predominant influence comes from the Africans, a lesser contribution from the South Indians, and a slight contribution from the Portuguese. Thus the original composition of the African genes among the Siddis has been diluted to some extent by the contribution from southern Indian population groups. There is no nonrandom association of alleles among a set of 10 genetic marker systems considered in the present study. The demonstration of genetic homogeneity of the Siddis, despite their admixed origin, suggests the utility of this population for genetic and epidemiological studies.

Intestinal helminths: a clue explaining the low incidence of inflammatory bowel diseases in Subsaharan Africa? Potential benefits and hazards of helminth therapy.

PubMed

Fiasse, René; Latinne, Dominique

2006-01-01

In their review, the authors state that the very low incidence and prevalence of IBD in sub-Saharan Africa cannot be explained by genetic factors since in Black populations of the U.S.A. and U.K., the incidence of these diseases is approaching that of the white populations. Beside helminths whose intestinal infestation is frequent in sub-Saharan Africa, other micro-organisms such as atypical mycobacteria, lactobacilli, etc, might have been reduced in Western population. This is a new variant of the Hygiene hypothesis. After Rook et al., these micro-organisms were acting as adjuvants for induction of T regulatory cells which, associated with antigen-presenting cells secrete IL-10 and TGF-beta, inhibiting the maturation of CD4 T cells to Th1 and Th2 effector cells, and consequently reducing the occurrence of Th1-mediated diseases like Crohn's disease and Th2-mediated diseases like ulcerative colitis. The effects of intestinal helminths on host immunity have been studied in Ethiopian Jews emigrated to Israel. Thorough studies before and after deworming have demonstrated that chronic helminth infestation provokes a state of chronic immune activation with anergy, reversible after deworming. Administration of ova of Trichuris suis, an helminth non pathogenic in man, has given encouraging results in the treatment o Crohn's disease and ulcerative colitis with a good safety record but long-term trials are needed since the potentially harmful effects of helminths on immunity.

Modeling the reversible kinetics of neutrophil aggregation under hydrodynamic shear.

PubMed Central

Neelamegham, S; Taylor, A D; Hellums, J D; Dembo, M; Smith, C W; Simon, S I

1997-01-01

Neutrophil emigration into inflamed tissue is mediated by beta 2-integrin and L-selectin adhesion receptors. Homotypic neutrophil aggregation is also dependent on these molecules, and it provides a model system in which to study adhesion dynamics. In the current study we formulated a mathematical model for cellular aggregation in a linear shear field based on Smoluchowski's two-body collision theory. Neutrophil suspensions activated with chemotactic stimulus and sheared in a cone-plate viscometer rapidly aggregate. Over a range of shear rates (400-800 s-1), approximately 90% of the single cells were recruited into aggregates ranging from doublets to groupings larger than sextuplets. The adhesion efficiency fit to these kinetics reached maximum levels of > 70%. Formed aggregates remained intact and resistant to shear up to 120 s, at which time they spontaneously dissociated back to singlets. The rate of cell disaggregation was linearly proportional to the applied shear rate, and it was approximately 60% lower for doublets as compared to larger aggregates. By accounting for the time-dependent changes in adhesion efficiency, disaggregation rate, and the effects of aggregate geometry, we succeeded in predicting the reversible kinetics of aggregation over a wide range of shear rates and cell concentrations. The combination of viscometry with flow cytometry and mathematical analysis as presented here represents a novel approach to differentiating between the effects of hydrodynamics and the intrinsic biological processes that control cell adhesion. Images FIGURE 3 FIGURE 5 PMID:9083659

The Regression Hypothesis as a Framework for First Language Attrition

ERIC Educational Resources Information Center

Keijzer, Merel

2010-01-01

In an attempt to explain first language attrition in emigrant populations, this paper investigates the explanatory power of a framework that has--until now--received little attention: the regression hypothesis (Jakobson, 1941). This hypothesis predicts that the order of attrition is the reverse of the order of acquisition. The regression…

The Emotional Impact of Forced Migration on Iranian-Americans

ERIC Educational Resources Information Center

Golestaneh, Hamideh

2015-01-01

In this phenomenological study, thematic analysis was used to gain a better understanding of the lived experience of six Iranian-Americans who migrate Iran for safety and a better life. The researcher assessed the participants' journey phase by phase, to get a deeper understanding of the phenomenon. Overall, emigrating from Iran had both negative…

Korean Americans in the United States: Problems and Alternatives.

ERIC Educational Resources Information Center

Kim, Eugene C.

Problems faced by Koreans in the United States are identified and analyzed in this paper, and some pragmatic remedies are offered. First, the acculturation process is slow--the mean of the Koreans' sojourn in the United States is only 6.5 years, whereas complete acculturation takes several generations. Second, although most Korean emigres learned…

Performance of Women Medical Graduates from Medical College, Baroda, 1949-74

ERIC Educational Resources Information Center

Bhatt, R. V.; And Others

1976-01-01

Women account for 15 percent of the total admissions in medicine and present overall better examinations than men. Obstetrics and gynecology is the most common speciality selected by women, and job satisfaction is found in 87 percent. Sixty-six percent are married to other doctors, and 39 percent emigrate. (Author/LBH)

The Great Irish Famine. 2nd Edition.

ERIC Educational Resources Information Center

Mullin, James

Between 1845 and 1850, more than a million Irish starved to death while massive quantities of food were being exported from their country. A half million were evicted from their homes during the potato blight. A million and a half emigrated to the United States, Britain, and Australia, often on board rotting, overcrowded "coffin ships."…

Race and Place in the Adaptation of Mariel Exiles.

ERIC Educational Resources Information Center

Skop, Emily H.

2001-01-01

The influx of lower class Cuban emigres during the 1980 Mariel Boatlift complicates the success story image of previous waves of Cuban exiles. Argues that place of incorporation should be a necessary ingredient in illuminating diverse adjustment experiences among immigrants and refugees to the United States. Concludes by discussing the Cuban…

The International Conference on Indochinese Refugees and Its Aftermath. Refugee Policy Group Issue Brief.

ERIC Educational Resources Information Center

Knowles, Michael

A conference on Indochinese refugees, attended by representatives of Southeast Asian countries of first asylum and Western resettlement countries, has developed a Comprehensive Plan of Action (CPA) prescribing new measures to address continuing emigration from Vietnam and Laos. The CPA calls for the following measures: (1) controls on departures…

Disfluency Markers in L1 Attrition

ERIC Educational Resources Information Center

Schmid, Monika S.; Fagersten, Kristy Beers

2010-01-01

Based on an analysis of the speech of long-term emigres of German and Dutch origin, the present investigation discusses to what extent hesitation patterns in language attrition may be the result of the creation of an interlanguage system, on the one hand, or of language-internal attrition patterns on the other. We compare speech samples elicited…

Soviet Muslim Emigres in the Republic of Turkey

DTIC Science & Technology

1992-05-01

traditional cuisine , proverbs and dances, great national heroes (abreks, Sheik Shamil and Imam Mansur etc) necrologies, poetry, short stories and...1-C: Books , Articles and Pamphlets..56 I-D. General Reference.... ................ CRIMEAN TATARS IN THE...REPUBLIC OF TURKEY 2-A: Summary ... .. ................ 2-B: Serials ......... ....... ....... 2-C Books , Articles and Pamphlets-_ .. . _ .69 2-D: General

Meeting the Social and Legal Needs of Urban Indians: An Experimental Program.

ERIC Educational Resources Information Center

Halverson, Lowell K.; Garrow, Tom

Approximately 40 percent of America's Indians live in urban environments; of these, about 12,000 live in Seattle, Washington. With no representation in local government, and lacking the power and cultural sophistication to make the political process work for them, many Indian emigres have developed an almost institutionalized distrust of and…

The Dysfunctionality of Russian Higher Professional Education

ERIC Educational Resources Information Center

Sheregi, F. E.

2011-01-01

The system of higher education in Russia is incapable of providing the kind of skilled labor force that the economy needs in order to move beyond its current, inadequate level of development. Unless the universities educate people that employers need, Russia will lose even more skilled people through emigration. (Contains 9 notes.) [This article…

"Contra Viento y Marea" (Against Wind and Tide): Building Civic Identity among Children of Emigration in El Salvador

ERIC Educational Resources Information Center

Dyrness, Andrea

2012-01-01

This article examines contrasting approaches to citizenship education in two schools in San Salvador, El Salvador, in the face of highly visible transnational migration. I argue that while transnational realities challenge education for democratic citizenship, educational processes that enable students to interrogate their own transnational…

Restless Youth: Emigration and Enterprise in Romania

ERIC Educational Resources Information Center

Mihailescu, Ioan

2004-01-01

The political changes in Romania after 1989 were followed by structural changes that affected all areas of social, economic, political, and cultural life. The transition from a 'closed' to an 'open' society has been difficult for East European countries, as the creation of institutions oriented towards competition and diversity has not led to an…

Immigration and Emigration: Canadian and Mexican Youth Making Sense of a Globalized Conflict

ERIC Educational Resources Information Center

Nieto, Diego; Bickmore, Kathy

2017-01-01

This paper discusses findings from focus groups with youth located in underprivileged surroundings in one large multicultural city in Canada and in a moderately large city in Mexico, examining their understandings and lived experiences of migration-related conflicts. Canadian participants framed these conflicts as a problem of racist attitudes…

The Influence of Globalization on Turkish Sports

ERIC Educational Resources Information Center

Sahin, Mehmet

2018-01-01

This paper addresses the phenomenon of globalization, which has also spread to sports, in terms of its economic, social and cultural aspects; while discussing the concept based on examples from the discipline of football in the premier league of Turkey. In this framework, sports labor emigration mobility is handled, and sponsorship and the effects…

Membership Contests: Encountering Immigrant Youth in Finland

ERIC Educational Resources Information Center

Harinen, Paivi; Suurpaa, Leena; Hoikkala, Tommi; Hautaniemi, Petri; Perho, Sini; Keskisalo, Anne-Mari; Kuure, Tapio; Kunnapuu, Krista

2005-01-01

This article discusses different aspects of social and societal membership, when minority groups of young immigrants living in Finland are under consideration. During its history, Finland has mainly been a country of emigration. In the 1990s the direction of moving turned to the contrary and the amount of immigrants in Finland increased relatively…

Parenting from Abroad: Migration, Nonresident Father Involvement, and Children's Education in Mexico

ERIC Educational Resources Information Center

Nobles, Jenna

2011-01-01

In Mexico, a country with high emigration rates, parental migration matches divorce as a contributor to child-father separation. Yet little has been written about children's relationships with migrating parents. In this study, I use nationally representative data from the 2005 Mexican Family Life Survey to model variation in the interaction…

Nothing to Do with Me! Teachers' Perceptions on Cultural Diversity in Spanish Secondary Schools

ERIC Educational Resources Information Center

Coronel, Jose M.; Gómez-Hurtado, Inmaculada

2015-01-01

One of the key effects of globalisation is the extraordinary increase in migratory movements. Spain, a country traditionally accustomed to emigration, has seen a considerable rise in the influx of immigrant population, with notable demographic, social and cultural transformations. Particularly, since the early 90s, schools have been experiencing…

How To Adopt Internationally: A Guide for Agency-Directed and Independent Adoptions. 2000-2002 Edition.

ERIC Educational Resources Information Center

Nelson-Erichsen, Jean; Erichsen, Heino R.

Many potential adoptive parents seeking international adoption find the process to be extremely complex. This guide details the international adoption process, including organizing a home study and fulfilling state requirements as well as selecting a country from which to adopt, working through emigration and immigration agencies, and traveling…

Supporting Two Households: Unaccompanied Mexican Minors and Their Absences from U.S. Schools

ERIC Educational Resources Information Center

Martinez, Isabel

2016-01-01

This article illustrates simultaneous household participation in the lives of undocumented, unaccompanied Mexican teenage minors in New York City and its impact on their school attendance. Emigrating without parents, some Mexican youths arrive to enter into the labor market, not school. Unable to assume monetary dependence, these youths' absences…

Tijuana: The Borders on the Move.

ERIC Educational Resources Information Center

Rigoni, Florenzo

1987-01-01

Presents a profile of Tijuana, Mexico, a city populated by thousands of Latino migrants and would-be emigrants, most living in dire poverty. Focuses on the Scalabrini Center, which provides help and protection without asking for names or citizenship papers. Discusses the impact of the Simpson-Rodino bill and considers the future of those displaced…

The Chinese in Children's Books.

ERIC Educational Resources Information Center

New York Public Library, NY.

This is a selective annotated list of children's books about China and the Chinese. Topics range from dynasties, the era of Western influence, emigration, revolution, to present day affairs. Most of the books have a Chinese setting, but some are about the Chinese in America. Listings are made under categories such as picture books, stories for…

Ezekiel Cheever (1614-1708), New England Colonial Teacher.

ERIC Educational Resources Information Center

Parker, Franklin; Parker, Betty J.

This paper narrates the life of Ezekiel Cheever, the most famous colonial New England Latin grammar teacher of his time. Cheever came from middle class Puritan roots in England, receiving a classical education before emigrating to Boston (Massachusetts). His remarkably long teaching career of 70 years in four New England towns and the esteem shown…

Policies for Migration and Development: A European Perspective. Policy Brief No. 30

ERIC Educational Resources Information Center

Katseli, Louka T.; Lucas, Robert E. B.; Xenogiani, Theodora

2006-01-01

Managing migration has become a priority for policy makers both in developed and developing countries. Large immigration or emigration flows relative to domestic population's impact on almost all aspects of an economy and society: family structures, community life, educational and health systems, labour markets, security systems, governance and…

Sociocultural Adaptations among Cuban Emigre Women in Miami, Florida.

ERIC Educational Resources Information Center

Gonzalez, Diana H.

This paper reports on Cuban women living in Miami (Florida) and their adaptation to life in exile. It includes an examination of health care practices, particularly the practice of self-diagnosis and self-prescription of minor tranquilizers as coping behaviors for dealing with acculturation and culture shock. Data were gathered from questionnaires…

Lise Meitner's escape from Germany

NASA Astrophysics Data System (ADS)

Sime, Ruth Lewin

1990-03-01

Lise Meitner (1878-1968) achieved prominence as a nuclear physicist in Germany; although of Jewish origin, her Austrian citizenship exempted her from Nazi racial laws until the annexation of Austria in 1938 precipitated her dismissal. Forbidden to emigrate, she narrowly escaped to the Netherlands with the help of concerned friends in the international physics community.

Polish Complementary Schools in Iceland and England

ERIC Educational Resources Information Center

Zielinska, Malgorzata; Kowzan, Piotr; Ragnarsdóttir, Hanna

2014-01-01

Since 2004, the opening of labour markets has spurred a considerable number of Poles to emigrate e.g. to Iceland and England. Families with school age children have had the challenge of adapting to foreign environments and school systems. Polish complementary schools have played an important, albeit ambivalent, role in this process. Through focus…

"Almajiri" Education: Policy and Practice to Meet the Learning Needs of the Nomadic Population in Nigeria

ERIC Educational Resources Information Center

Olaniran, Sunday Olawale

2018-01-01

This article explores the provision of education opportunities to a disadvantaged group in Nigeria known as "Almajiris." The word "Almajiri" derives from the Arabic word "Almuhajirun," meaning emigrant. The nomadic pastoralists of northern Nigeria constitute a major socio-economic group. According to a recent report…

Unauthorized Immigration to the United States: Annual Estimates and Components of Change, by State, 1990 to 2010.

PubMed

Warren, Robert; Warren, John Robert

2013-06-01

We describe a method for producing annual estimates of the unauthorized immigrant population in the United Sates and components of population change, for each state and D.C., for 1990 to 2010. We quantify a sharp drop in the number of unauthorized immigrants arriving since 2000, and we demonstrate the role of departures from the population (emigration, adjustment to legal status, removal by the Department of Homeland Security (DHS), and deaths) in reducing population growth from one million in 2000 to population losses in 2008 and 2009. The number arriving in the U.S. peaked at more than one million in 1999 to 2001, and then declined rapidly through 2009. We provide evidence that population growth stopped after 2007 primarily because entries declined and not because emigration increased during the economic crisis. Our estimates of the total unauthorized immigrant population in the U.S. and in the top ten states are comparable to those produced by DHS and the Pew Hispanic Center. For the remaining states and D.C., our data and methods produce estimates with smaller ranges of sampling error.

Skilled migration and health outcomes in developing countries.

PubMed

Uprety, Dambar

2018-04-30

Many studies have found that health outcomes decline when health professionals leave the country, but do such results remain consistent in gender- and income-disaggregated skilled migration? To help uncover explanations for such a pro-migration nature of health outcomes, the present study revisits this topic but allows for associations of skilled migration with mortality and life expectancy to differ between male and female, and between low- and high-income countries. Using a panel of 133 developing countries as source and 20 OECD countries as destination from 1980 to 2010 allowing the coefficient on emigration across different education levels to differ, the study finds the negative effect of high-skilled emigration on health outcomes. Such effect is more pronounced for high-skilled female migration than those for male and for low-income countries than for middle-and high-income countries. Results also show that such adverse effect is larger for African countries than non-African ones. However, the low-skilled migration appears to be insignificant to affect health outcomes in developing countries. Thus, skilled migration is detrimental to longevity in developing countries but unskilled migration is not.

International migration of partner, autonomy and depressive symptoms among women from a mexican rural area.

PubMed

Bojorquez, Ietza; Salgado de Snyder, Nelly; Casique, Irene

2009-07-01

The emigration of Mexicans to the USA has increased in the last decades, and little is known about the effect of this on the mental health of those who stay behind. To evaluate the association of emigration of husband and depressive symptoms (DS) among women who stay in Mexico. We also tested the hypothesis that the husband's migration would increase the woman's autonomy, which in turn would decrease DS. A survey was conducted in a rural area in Mexico. Participants (n = 418) were selected through probabilistic sampling in three stages: localities, households and individuals. DS were evaluated using the Centre for Epidemiological Studies-Depression (CES-D) scale. Having a partner in the USA was associated with higher odds of scoring above the cut-off point in CES-D (OR 3.77, 95% CI 1.92-7.43). Economic autonomy was also associated with DS (OR 1.45, 95% CI 1.04-2.02). Migration of husband was associated with DS among women. The construct of autonomy and its operational definition should be further explored.

Unusual dynamics of extinction in a simple ecological model.

PubMed Central

Sinha, S; Parthasarathy, S

1996-01-01

Studies on natural populations and harvesting biological resources have led to the view, commonly held, that (i) populations exhibiting chaotic oscillations run a high risk of extinction; and (ii) a decrease in emigration/exploitation may reduce the risk of extinction. Here we describe a simple ecological model with emigration/depletion that shows behavior in contrast to this. This model displays unusual dynamics of extinction and survival, where populations growing beyond a critical rate can persist within a band of high depletion rates, whereas extinction occurs for lower depletion rates. Though prior to extinction at lower depletion rates the population exhibits chaotic dynamics with large amplitudes of variation and very low minima, at higher depletion rates the population persists at chaos but with reduced variation and increased minima. For still higher values, within the band of persistence, the dynamics show period reversal leading to stability. These results illustrate that chaos does not necessarily lead to population extinction. In addition, the persistence of populations at high depletion rates has important implications in the considerations of strategies for the management of biological resources. PMID:8643661

Emigration and development: the case of a Bangladeshi village.

PubMed

Rahman, M M

2000-01-01

This article examines the developmental consequences of international labor migration in a Bangladeshi village. The data are from the Hoglakandi, a village 30 km southeast of Dhaka, capital of Bangladesh. A structured questionnaire with both open-ended and closed category questions was used among 50 Singapore returnees, supplemented with additional in-depth interviews. International labor migration has often been seen by many sending countries as a short cut development because of its role in unemployment relief, balance of payments relief, and capital formation of national level. The study argues that the causes and effects of emigration can better be understood only when the process is placed within its local context, since what may prove to be advantageous at the national level may prove to be detrimental to a household or community or vice-versa. It demonstrates how the contribution of labor migration is merely the transformation of labor into a structural component of the international political economy. The Hoglakandi experience reveals that labor migration does not fuel the local economy from an external pipeline of remittances and skill acquisition, rather it drains local resources that retard the development.

INTERNATIONAL MIGRATION AND THE EDUCATION OF CHILDREN: EVIDENCE FROM LIMA, PERU

PubMed Central

Robles, Verónica Frisancho; Oropesa, R.S.

2012-01-01

The issue of whether emigration has consequences for the education of children who remain behind in the country of origin occupies an increasingly prominent place in the agendas of both scholars and policy makers. The conventional wisdom is that the emigration of family members may benefit children by relaxing budget constraints through remittances that can be used to cover educational expenses. However, the empirical evidence on the overall effect of migration is inconclusive. This is due in part to a substantive emphasis on remittances in the literature, as well as the inability of some studies to deal satisfactorily with the endogeneity of household migration decisions in comparing outcomes across migrant and non-migrant households. Using Peruvian data from the Latin American Migration Project (LAMP), we apply an innovative instrumental variable technique to evaluate the overall effect of migration on educational attainment and schooling disruption among the children of immigrants. In contrast to conventional wisdom, our results suggest that a higher household risk of immigration has deleterious consequences for the education of children who remain behind. PMID:22581990

Fish distribution during smolt migration in the Penobscot Estuary, ME

NASA Astrophysics Data System (ADS)

Volkel, S. L.

2016-02-01

Estuaries are complex and dynamic ecosystems. The Penobscot Estuary is particularly important because it harbors a suite of imperiled diadromous fish species. In order to properly manage these populations, it is imperative to understand their distribution and ecology. My study focuses on May because endangered Atlantic salmon migrate seaward then. Successful emigration of these smolts is important to the population's overall fitness. One potential way to increase the likelihood of migratory success (survival) is to decrease their risk of predation. Assuming that predators in this system are generalists, overall smolt predation may be reduced by having a larger selection of alternative prey (other fish species). We hypothesize that diadromous fish abundance is increasing as a result of recent (2012-2013) dam removals. To explore this hypothesis, I used hydroacoustic methods to characterize the distribution patterns of alternative prey (TL=10-30 cm). I found that peak fish abundances occurred in the mid-estuary, especially during mid-May, and depth distribution patterns varied weekly. By understanding these seasonal, longitudinal, and vertical distribution patterns, I explored potential interactions of other fish populations as prey buffers to emigrating smolts.

Effectiveness of an integrated hatchery program: Can genetic-based performance differences between hatchery and wild Chinook salmon be avoided?

USGS Publications Warehouse

Hayes, Michael C.; Reisenbichler, Reginald R.; Rubin, Stephen P.; Drake, Deanne C.; Stenberg, Karl D.; Young, Sewall F.

2013-01-01

Performance of wild (W) and hatchery (H) spring Chinook salmon (Oncorhynchus tshawytscha) was evaluated for a sixth generation hatchery program. Management techniques to minimize genetic divergence from the wild stock included regular use of wild broodstock and volitional releases of juveniles. Performance of HH, WW, and HW (hatchery female spawned with wild male) crosses was compared in hatchery and stream environments. The WW juveniles emigrated from the hatchery at two to three times the rate of HH fish in the fall (HW intermediate) and 35% more HH than WW adults returned (27% more HW than WW adults). Performance in the stream did not differ statistically between HH and WW fish, but outmigrants (38% WW, 30% HW, and 32% HH fish) during the first 39 days of the 16-month sampling period composed 74% of total outmigrants. Differences among hatchery-reared crosses were partially due to additive genetic effects, were consistent with domestication (increased fitness for the hatchery population in the hatchery program), and suggested that selection against fall emigration from the hatchery was a possible mechanism of domestication.

Hospitalization flow in the public and private systems in the state of Sao Paulo, Brazil

PubMed Central

Rocha, Juan Stuardo Yazlle; Monteiro, Rosane Aparecida; Moreira, Marizélia Leão

2015-01-01

OBJECTIVE To describe the migration flows of demand for public and private hospital care among the health regions of the state of Sao Paulo, Brazil. METHODS Study based on a database of hospitalizations in the public and private systems of the state of Sao Paulo, Southeastern Brazil, in 2006. We analyzed data from 17 health regions of the state, considering people hospitalized in their own health region and those who migrated outwards (emigration) or came from other regions (immigration). The index of migration effectiveness of patients from both systems was estimated. The coverage (hospitalization coefficient) was analyzed in relation to the number of inpatient beds per population and the indexes of migration effectiveness. RESULTS The index of migration effectiveness applied to the hospital care demand flow allowed characterizing health regions with flow balance, with high emigration of public and private patients, and with high attraction of public and private patients. CONCLUSIONS There are differences in hospital care access and opportunities among health regions in the state of Sao Paulo, Brazil. PMID:26465661

Paleoclimate and Amerindians: Evidence from stable isotopes and atmospheric circulation

USGS Publications Warehouse

Lovvorn, M.B.; Frison, G.C.; Tieszen, L.L.

2001-01-01

Two Amerindian demographic shifts are attributed to climate change in the northwest plains of North America: at ???11,000 calendar years before present (yr BP), Amerindian culture apparently split into foothills-mountains vs. plains biomes; and from 8,000-5,000 yr BP, scarce archaeological sites on the open plains suggest emigration during xeric "Altithermal" conditions. We reconstructed paleoclimates from stable isotopes in prehistoric bison bone and relations between weather and fractions of C4 plants in forage. Further, we developed a climate-change model that synthesized stable isotope, existing qualitative evidence (e.g., palynological, erosional), and global climate mechanisms affecting this midlatitude region. Our isotope data indicate significant warming from ???12,400 to 11,900 yr BP, supporting climate-driven cultural separation. However, isotope evidence of apparently wet, warm conditions at 7,300 yr BP refutes emigration to avoid xeric conditions. Scarcity of archaeological sites is best explained by rapid climate fluctuations after catastrophic draining of the Laurentide Lakes, which disrupted North Atlantic Deep Water production and subsequently altered monsoonal inputs to the open plains.

Hospitalization flow in the public and private systems in the state of Sao Paulo, Brazil.

PubMed

Rocha, Juan Stuardo Yazlle; Monteiro, Rosane Aparecida; Moreira, Marizélia Leão

2015-01-01

OBJECTIVE To describe the migration flows of demand for public and private hospital care among the health regions of the state of Sao Paulo, Brazil.METHODS Study based on a database of hospitalizations in the public and private systems of the state of Sao Paulo, Southeastern Brazil, in 2006. We analyzed data from 17 health regions of the state, considering people hospitalized in their own health region and those who migrated outwards (emigration) or came from other regions (immigration). The index of migration effectiveness of patients from both systems was estimated. The coverage (hospitalization coefficient) was analyzed in relation to the number of inpatient beds per population and the indexes of migration effectiveness.RESULTS The index of migration effectiveness applied to the hospital care demand flow allowed characterizing health regions with flow balance, with high emigration of public and private patients, and with high attraction of public and private patients.CONCLUSIONS There are differences in hospital care access and opportunities among health regions in the state of Sao Paulo, Brazil.

IJEPA: Gray Area for Health Policy and International Nurse Migration.

PubMed

Efendi, Ferry; Mackey, Timothy Ken; Huang, Mei-Chih; Chen, Ching-Min

2017-05-01

Indonesia is recognized as a nurse exporting country, with policies that encourage nursing professionals to emigrate abroad. This includes the country's adoption of international principles attempting to protect Indonesian nurses that emigrate as well as the country's own participation in a bilateral trade and investment agreement, known as the Indonesia-Japan Economic Partnership Agreement that facilitates Indonesian nurse migration to Japan. Despite the potential trade and employment benefits from sending nurses abroad under the Indonesia-Japan Economic Partnership Agreement, Indonesia itself is suffering from a crisis in nursing capacity and ensuring adequate healthcare access for its own populations. This represents a distinct challenge for Indonesia in appropriately balancing domestic health workforce needs, employment, and training opportunities for Indonesian nurses, and the need to acknowledge the rights of nurses to freely migrate abroad. Hence, this article reviews the complex operational and ethical issues associated with Indonesian health worker migration under the Indonesia-Japan Economic Partnership Agreement. It also introduces a policy proposal to improve performance of the Indonesia-Japan Economic Partnership Agreement and better align it with international principles focused on equitable health worker migration.

Proto-industrialization, sharecropping, and outmigration in nineteenth-century rural Westphalia.

PubMed

Anderson, T G

2001-01-01

This article examines proto-industrialization and the social relations of production in a rural parish in eastern Westphalia that experienced large-scale outmigration to the American Midwest in the mid-nineteenth century. Relying on local and individual-level Prussian tax and emigration records, the study identifies and analyses the socio-economic background of the migrant cohort in terms of proto-industrial activity and peasant economy. Preceded by the downfall of domestic textile industries due to British industrial competition, outmigration was highly selective, drawing individuals from specific socio-economic niches. Landless sharecroppers - linked by debt and labour obligations to better-off peasants and landlords - were underrepresented in the migration, while smallholding peasants and day-labourers - 'free' to commodify their labour power through the sale of home-produced textile products or seasonal migratory labour - were overrepresented. The findings of the study have implications for an understanding of the localized nature of the relations of production in proto-industrial regions, the historical nature of German emigrations, and the dynamics of the German transition to industrial capitalism in the nineteenth century.

The development of the neural crest in the human

PubMed Central

O’Rahilly, Ronan; Müller, Fabiola

2007-01-01

The first systematic account of the neural crest in the human has been prepared after an investigation of 185 serially sectioned staged embryos, aided by graphic reconstructions. As many as fourteen named topographical subdivisions of the crest were identified and eight of them give origin to ganglia (Table 2). Significant findings in the human include the following. (1) An indication of mesencephalic neural crest is discernible already at stage 9, and trigeminal, facial, and postotic components can be detected at stage 10. (2) Crest was not observed at the level of diencephalon 2. Although pre-otic crest from the neural folds is at first continuous (stage 10), crest-free zones are soon observable (stage 11) in Rh.1, 3, and 5. (3) Emigration of cranial neural crest from the neural folds at the neurosomatic junction begins before closure of the rostral neuropore, and later crest cells do not accumulate above the neural tube. (4) The trigeminal, facial, glossopharyngeal and vagal ganglia, which develop from crest that emigrates before the neural folds have fused, continue to receive contributions from the roof plate of the neural tube after fusion of the folds. (5) The nasal crest and the terminalis-vomeronasal complex are the last components of the cranial crest to appear (at stage 13) and they persist longer. (6) The optic, mesencephalic, isthmic, accessory, and hypoglossal crest do not form ganglia. Cervical ganglion 1 is separated early from the neural crest and is not a Froriep ganglion. (7) The cranial ganglia derived from neural crest show a specific relationship to individual neuromeres, and rhombomeres are better landmarks than the otic primordium, which descends during stages 9–14. (8) Epipharyngeal placodes of the pharyngeal arches contribute to cranial ganglia, although that of arch 1 is not typical. (9) The neural crest from rhombomeres 6 and 7 that migrates to pharyngeal arch 3 and from there rostrad to the truncus arteriosus at stage 12 is identified here, for the first time in the human, as the cardiac crest. (10) The hypoglossal crest provides cells that accompany those of myotomes 1–4 and form the hypoglossal cell cord at stages 13 and 14. (11) The occipital crest, which is related to somites 1–4 in the human, differs from the spinal mainly in that it does not develop ganglia. (12) The occipital and spinal portions of the crest migrate dorsoventrad and appear to traverse the sclerotomes before the differentiation into loose and dense zones in the latter. (13) Embryonic examples of synophthalmia and anencephaly are cited to emphasize the role of the neural crest in the development of cranial ganglia and the skull. PMID:17848161

Aeromonas salmonicida Infection Only Moderately Regulates Expression of Factors Contributing to Toll-Like Receptor Signaling but Massively Activates the Cellular and Humoral Branches of Innate Immunity in Rainbow Trout (Oncorhynchus mykiss)

PubMed Central

Brietzke, Andreas; Korytář, Tomáš; Jaros, Joanna; Köllner, Bernd; Goldammer, Tom; Seyfert, Hans-Martin; Rebl, Alexander

2015-01-01

Toll-like receptors (TLRs) are known to detect a defined spectrum of microbial structures. However, the knowledge about the specificity of teleost Tlr factors for distinct pathogens is limited so far. We measured baseline expression profiles of 18 tlr genes and associated signaling factors in four immune-relevant tissues of rainbow trout Oncorhynchus mykiss. Intraperitoneal injection of a lethal dose of Aeromonas salmonicida subsp. salmonicida induced highly increased levels of cytokine mRNAs during a 72-hour postinfection (hpi) period. In contrast, only the fish-specific tlr22a2 and the downstream factor irak1 featured clearly increased transcript levels, while the mRNA concentrations of many other tlr genes decreased. Flow cytometry quantified cell trafficking after infection indicating a dramatic influx of myeloid cells into the peritoneum and a belated low level immigration of lymphoid cells. T and B lymphocytes were differentiated with RT-qPCR revealing that B lymphocytes emigrated from and T lymphocytes immigrated into head kidney. In conclusion, no specific TLR can be singled out as a dominant receptor for A. salmonicida. The recruitment of cellular factors of innate immunity rather than induced expression of pathogen receptors is hence of key importance for mounting a first immune defense against invading A. salmonicida. PMID:26266270

The metrics and correlates of physician migration from Africa.

PubMed

Arah, Onyebuchi A

2007-05-17

Physician migration from poor to rich countries is considered an important contributor to the growing health workforce crisis in the developing world. This is particularly true for Africa. The perceived magnitude of such migration for each source country might, however, depend on the choice of metrics used in the analysis. This study examined the influence of choice of migration metrics on the rankings of African countries that suffered the most physician migration, and investigated the correlates of physician migration. Ranking and correlational analyses were conducted on African physician migration data adjusted for bilateral net flows, and supplemented with developmental, economic and health system data. The setting was the 53 African birth countries of African-born physicians working in nine wealthier destination countries. Three metrics of physician migration were used: total number of physician émigrés; emigration fraction defined as the proportion of the potential physician pool working in destination countries; and physician migration density defined as the number of physician émigrés per 1000 population of the African source country. Rankings based on any of the migration metrics differed substantially from those based on the other two metrics. Although the emigration fraction and physician migration density metrics gave proportionality to the migration crisis, only the latter was consistently associated with source countries' workforce capacity, health, health spending, economic and development characteristics. As such, higher physician migration density was seen among African countries with relatively higher health workforce capacity (0.401 < or = r < or = 0.694, p < or = 0.011), health status, health spending, and development. The perceived magnitude of physician migration is sensitive to the choice of metrics. Complementing the emigration fraction, the physician migration density is a metric which gives a different but proportionate picture of which African countries stand to lose relatively more of its physicians with unchecked migration. The nature of health policies geared at health-worker migration can be expected to depend on the choice of migration metrics.

[Demography and employment in Portugal].

PubMed

Barata, O S

1981-01-01

The population of Portugal showed a period of slow growth between 1950-60; however, in the 1970s, the return of large numbers of former residents in African territories along with a reduction in emigration changed the trend so that the 1981 census showed a significant increase. The Portuguese economy, on the other hand, is in a state of crisis which has resulted in large numbers of unemployed. The growth of the population along with these hard times has made it more difficult to reduce the rate of unemployment. It is also more difficult for those leaving school to find jobs. The better educated generations are seeking jobs in industry and in other services that Portugal will find difficult to offer in sufficient numbers in the immediate future. At present, the Portuguese economy has a large component of agricultural labor. In any case, the means of economic and social intervention to fight unemployment have limited potential. Therefore, many of those unable to find jobs in Portugal will attempt to emigrate. Many Portuguese are already working in Germany, France, and in other Western European countries but migration today is much more difficult. In addition, these countries cannot be expected to recive many more migrant workers in the future. In fact, those better educated workers from Portugal will not be very interested in the low paying jobs which can be found more easily by foreign workers in Western Euorpe. Many will therefore attempt to find jobs in non-European countries. There has been a recent increase of migration to Canada and the US. A renewal of interest in jobs in Brazil and other South Amerian countries is also to be expected. There may also be a future increase in the number of experts, technicians, and other qualified personnel emigrating to Portuguese speaking African countries if there is adequate security and if these countries find the way to expand economic growth. (author's modified)

Breeding pond selection and movement patterns by eastern spadefoot toads (Scaphiopus holbrookii) in relation to weather and edaphic conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cathryn H. Greenberg; George W. Tanner

2004-08-31

Cathryn H. Greenberg and George W. Tanner. 2004. Breeding pond selection and movement patterns by eastern spadefoot toads (Scaphiopus holbrookii) in relation to weather and edaphic conditions. J. Herp. 38(4):569-577. Abstract: Eastern Spadefoot Toads (Scaphiopus holbrookii) require fish-free, isolated, ephemeral ponds for breeding but otherwise inhabit the surrounding uplands, commonly xeric longleaf pine (Pinus palustris) wiregrass (Aristida beyrichiana). Hence both pond and upland conditions can potentially affect their breeding biology, and population persistence. Hardwood invasion due to fire suppression in sandhills could alter upland and pond suitability by higher hardwood density and increased transpiration. In this paper we explore breedingmore » and neonatal emigration movements in relation to weather, hydrological conditions of ponds, and surrounding upland matrices. We use 9 years of data from continuous monitoring with drift fences and pitfall traps at 8 ephemeral ponds in 2 upland matrices: regularly-burned, savanna-like sandhills (n = 4), and hardwood-invaded sandhills (n = 4). Neither adult nor neonate captures differed between ponds within the 2 upland matrices, suggesting that they are tolerant of upland heterogeneity created by fire frequency. Explosive breeding occurred during 9 periods and in all seasons; adults were captured rarely otherwise. At a landscape-level rainfall, maximum change in barometric pressure, and an interaction between those 2 variables were significant predictors of explosive breeding. At a pond-level, rainfall, change in pond depth during the month prior to breeding, and days since a pond was last dry were significant predictors of adult captures. Transformation date, rather than weather, was associated with neonatal emigrations, which usually were complete within a week. Movement by first-captured adults and neonates was directional, but adult emigrations were apparently not always toward their origin. Our results suggest that Spadefoot Toads are highly adapted to breeding conditions and upland habitat heterogeneity created by weather patterns and fire frequency in Florida sandhills.« less

Carryover aquatic effects on survival of metamorphic frogs during pond emigration

USGS Publications Warehouse

Chelgren, N.D.; Rosenberg, D.K.; Heppell, S.S.; Gitelman, A.I.

2006-01-01

In organisms with complex life cycles, physiological stressors during early life stages may have fitness-level impacts that are delayed into later stages or habitats. We tested the hypothesis that body size and date of metamorphosis, which are highly responsive to aquatic stressors, influence post-metamorphic survival and movement patterns in the terrestrial phase of an ephemeral pond-breeding frog by examining these traits in two populations of northern red-legged frogs (Rana aurora aurora). To increase variation of body size at metamorphosis, we manipulated food availability for 314 of 1045 uniquely marked tadpoles and estimated the probability that frogs survived and emigrated using concentric rings of drift fencing surrounding ponds and Bayesian capture-recapture modeling. The odds of surviving and emigrating from the ponds to the innermost drift fences, ???12 m, increased by factors of 2.20 (95% credibility intervals 1.39-4.23) and 2.54 (0.94-4.91) with each millimeter increase in snout-vent length and decreased by factors of 0.91 (0.85-0.96) and 0.89 (0.80-1.00) with each day's delay in metamorphosis for the two ponds. The odds of surviving and moving to the next ring of fencing, 12 m to ???40 m from the ponds, increased by a factor of 1.20 (0.45-4.06) with each millimeter increase in size. Our results demonstrated that body size and timing of metamorphosis relate strongly to the performance of newly metamorphosed frogs during their initial transition into terrestrial habitat. Carryover effects of aquatic stressors that reduce size and delay metamorphosis may have population-level impacts that are not expressed until terrestrial stages. Since changes in both aquatic and terrestrial systems are implicated in many amphibian declines, quantifying both immediate and delayed effects of stressors on demographic rates is critical to sound management. ?? 2006 by the Ecological Society of America.

Species richness and occupancy estimation in communities subject to temporary emigration

USGS Publications Warehouse

Kery, M.; Royle, J. Andrew; Plattner, M.; Dorazio, R.M.

2009-01-01

Species richness is the most common biodiversity metric, although typically some species remain unobserved. Therefore, estimates of species richness and related quantities should account for imperfect detectability. Community dynamics can often be represented as superposition of species-specific phenologies (e. g., in taxa with well-defined flight [insects], activity [rodents], or vegetation periods [plants]). We develop a model for such predictably open communities wherein species richness is expressed as the sum over observed and unobserved species of estimated species-specific and site-specific occurrence indicators and where seasonal occurrence is modeled as a species-specific function of time. Our model is a multispecies extension of a multistate model with one unobservable state and represents a parsimonious way of dealing with a widespread form of 'temporary emigration.'' For illustration we use Swiss butterfly monitoring data collected under a robust design (RD); species were recorded on 13 transects during two secondary periods within <= 7 primary sampling periods. We compare estimates with those under a variation of the model applied to standard data, where secondary samples are pooled. The latter model yielded unrealistically high estimates of total community size of 274 species. In contrast, estimates were similar under models applied to RD data with constant (122) or seasonally varying (126) detectability for each species, but the former was more parsimonious and therefore used for inference. Per transect, 6 44 (mean 21.1) species were detected. Species richness estimates averaged 29.3; therefore only 71% (range 32-92%) of all species present were ever detected. In any primary period, 0.4-5.6 species present were overlooked. Detectability varied by species and averaged 0.88 per primary sampling period. Our modeling framework is extremely flexible; extensions such as covariates for the occurrence or detectability of individual species are easy. It should be useful for communities with a predictable form of temporary emigration where rigorous estimation of community metrics has proved challenging so far.

Environmental correlates of temporary emigration for female Weddell seals and consequences for recruitment

USGS Publications Warehouse

Stauffer, Glenn E.; Rotella, Jay J.; Garrott, Robert A.; Kendall, William L.

2014-01-01

In colonial-breeding species, prebreeders often emigrate temporarily from natal reproductive colonies then subsequently return for one or more years before producing young. Variation in attendance–nonattendance patterns can have implications for subsequent recruitment. We used open robust-design multistate models and 28 years of encounter data for prebreeding female Weddell seals (Leptonychotes weddellii [Lesson]) to evaluate hypotheses about (1) the relationships of temporary emigration (TE) probabilities to environmental and population size covariates and (2) motivations for attendance and consequences of nonattendance for subsequent probability of recruitment to the breeding population. TE probabilities were density dependent (βˆBPOP = 0.66,  = 0.17; estimated effects [β] and standard errors of population size in the previous year) and increased when the fast-ice edge was distant from the breeding colonies (βˆDIST = 0.75,  = 0.04; estimated effects and standard errors of distance to the sea-ice edge in the current year on TE probability in the current year) and were strongly age and state dependent. These results suggest that trade-offs between potential benefits and costs of colony attendance vary annually and might influence motivation to attend colonies. Recruitment probabilities were greatest for seals that consistently attended colonies in two or more years (e.g.,  = 0.56, SD = 0.17) and lowest for seals that never or inconsistently attended prior to recruitment (e.g.,  = 0.32, SD = 0.15), where denotes the mean recruitment probability (over all years) for 10-year-old seals for the specified prebreeder state. In colonial-breeding seabirds, repeated colony attendance increases subsequent probability of recruitment to the adult breeding population; our results suggest similar implications for a marine mammal and are consistent with the hypothesis that prebreeders were motivated to attend reproductive colonies to gain reproductive skills or perhaps to optimally synchronize estrus through close association with mature breeding females.

Climate of migration? How climate triggered migration from southwest Germany to North America during the 19th century

NASA Astrophysics Data System (ADS)

Glaser, Rüdiger; Himmelsbach, Iso; Bösmeier, Annette

2017-11-01

This paper contributes to the ongoing debate on the extent to which climate and climatic change can have a negative impact on societies by triggering migration, or even contribute to conflict. It summarizes results from the transdisciplinary project Climate of migration (funded 2010-2014), whose innovative title was created by Franz Mauelshagen and Uwe Lübken. The overall goal of this project was to analyze the relation between climatic and socioeconomic parameters and major migration waves from southwest Germany to North America during the 19th century. The article assesses the extent to which climatic conditions triggered these migration waves. The century investigated was in general characterized by the Little Ice Age with three distinct cooling periods, causing major glacier advances in the alpine regions and numerous climatic extremes such as major floods, droughts and severe winter. Societal changes were tremendous, marked by the warfare during the Napoleonic era (until 1815), the abolition of serfdom (1817), the bourgeois revolution (1847/48), economic freedom (1862), the beginning of industrialization accompanied by large-scale rural-urban migration resulting in urban poverty, and finally by the foundation of the German Empire in 1871.

The presented study is based on quantitative data and a qualitative, information-based discourse analysis. It considers climatic conditions as well as socioeconomic and political issues, leading to the hypothesis of a chain of effects ranging from unfavorable climatic conditions to a decrease in crop yields to rising cereal prices and finally to emigration. These circumstances were investigated extensively for the peak emigration years identified with each migration wave. Furthermore, the long-term relations between emigration and the prevailing climatic conditions, crop yields and cereal prices were statistically evaluated with a sequence of linear models which were significant with explanatory power between 22 and 38 %.

Resources of Recent Migrants to Rural Areas for Economic Development: Policy Implications.

ERIC Educational Resources Information Center

Bradshaw, Ted K.; Blakely, Edward J.

Using in-person questionnaires, 553 newcomers and 106 long-term residents were interviewed in late 1979 and early 1980 in 5 small northern California communities to explore the role of newcomers in developing the rural economy, and especially to analyze the resources emigrants bring with them: their skills, education, background, and business and…

Mexico: The Role of the Participatory Media in Immigration/Emigration as Culture and Political Economy.

ERIC Educational Resources Information Center

Oseguera, A. Anthony

Mexican mass media, especially television, incorporates an abundance of American programming and serves as a catalyst to motivate lower strata Mexicans to pursue life in the United States, resulting in a tremendous influx of both legal and illegal Mexicans and other Latin Americans to the United States. Although Mexico benefits because many…

The Emigrants: "Straight Outta Compton, Dope," and Emerging from the Ghetto

ERIC Educational Resources Information Center

Beck, Bernard

2016-01-01

Many recent movies about African American life have focused on people leaving the ghetto. Earlier movies about groups living in ghettoes have portrayed the ghetto as a permanent reality. Moviemakers explored ghetto life as an interesting subject and a source of cultural innovation. Life was hard, but social and cultural ways to cope with…

Quality of Life in Rural Areas: Processes of Divergence and Convergence

ERIC Educational Resources Information Center

Spellerberg, Annette; Huschka, Denis; Habich, Roland

2007-01-01

In Germany, processes can be observed that have long been out of keeping with the principle of equality of opportunity. Unemployment is concentrated in the structurally weak peripheral areas, in Eastern Germany in particular; emigration of young and better-educated people to the West is not diminishing, but contrary to expectation is again on the…

[The demographic and occupational characteristics of Italian migrants to Argentina, 1880-1930].

PubMed

Cacopardo, M C; Moreno, J L

1984-09-01

"This essay studies...the demographic and socio-professional characteristics of the Italian emigrants in Argentina during the period 1880-1930. Besides a reconstruction of the demographic variables (age, sex, mortality, and fertility) in the historical series, the essay also depicts the professional profile of the Italians in Argentina...." (summary in ENG, FRE) excerpt

On the Teaching of Japanese: The State of the Art.

ERIC Educational Resources Information Center

Martin, Samuel E.

Until the coming of World War II, little interest was shown in the teaching of Japanese outside Japan except for the elementary schools set up to inculcate the ways of the homeland among the offspring of Japanese emigrants to places like Hawaii, the Pacific Coast of North America, and Brazil. A few European and American universities offered…

Emigration for Higher Education: The Case of Palestinians Living in Israel Studying in Jordan

ERIC Educational Resources Information Center

Arar, Khalid; Haj-Yehia, Kussai

2010-01-01

This study explored reasons for the rapid increase in the number of Palestinian Arabs from Israel (PAI) studying higher education (HE) in Jordan. Four hundred and sixty PAI studying in Jordan answered a questionnaire assessing factors related to HE in both countries. Lenient admission requirements and cultural-language similarity explain Jordan's…

Froebel Crosses the Alps: Introducing the Kindergarten in Italy

ERIC Educational Resources Information Center

Albisetti, James C.

2009-01-01

The kindergarten was, in all countries but Germany, a foreign import. The most familiar aspect of its diffusion to American scholars is the spread of Froebel's teachings into England and the United States by emigrants who had left the German Confederation after the failure of the revolutions of 1848-49. Familiar as well are the propaganda efforts…

Chicano Literature of the Midwest: The Production of "Los Desarraigados."

ERIC Educational Resources Information Center

McAlpine, Dave

Following a brief discussion of the origins of the Chicanos in the Midwest, this paper surveys and quotes at length from several Spanish language periodicals produced in the Midwest between 1925 and the early 1980s. Discussion of the Chicano origins in the Midwest touches on emigration resulting from the Mexican Revolution of 1910-1917, the…

The Influence of Academic Migration on the Intellectual Potential of Russia

ERIC Educational Resources Information Center

Latova, Natalia V.; Savinkov, Vladimir I.

2012-01-01

The emigration of highly-qualified academics ("brain drain") is considered an essential factor in the decline of the human capital of post-Soviet Russia. However, statistics show that the scale of this phenomenon since 2000 was minor. The Russian scientists who went abroad for permanent residence or for a contract job abroad represented…

Arabs in the New World: Studies on Arab-American Communities.

ERIC Educational Resources Information Center

Abraham, Sameer Y., Ed.; Abraham, Nabeel, Ed.

This book is a collection of articles and research materials on Arab-Americans. Part one of the book provides an historical overview of Arab-Americans, their reasons for emigration from Greater Syria, and profiles of the two major religious groups, Muslims and Christians, in the United States Arab population. Authors of this section include Alixa…

Foreign Area Studies in the USSR. Training and Employment of Specialists.

ERIC Educational Resources Information Center

Gottemoeller, Rose E.; Langer, Paul F.

A study was undertaken to arrive at a broad overview of the Soviet training utilization of foreign area specialists. To gather data for the study, researchers examined European, United States, and Soviet publications and interviewed Soviet emigres and U.S. specialists on the Soviet Union. According to these data sources, specialized training for…

Children of Immigrants in Trento: Educational Achievement through the Lens of Friendship

ERIC Educational Resources Information Center

Mantovani, Debora; Martini, Elisa

2008-01-01

During the past three decades, Italy has changed from a country of emigration to one of immigration. This has produced significant changes in the country's social, cultural and economic structures and poses major new challenges to the education system. An important indicator of the changing situation is the increasing number of immigrant children…

A Postwar Perversion of "Testimonio" in Horacio Castellanos Moya's "El asco"

ERIC Educational Resources Information Center

Thornton, Megan

2014-01-01

Salvadoran writer Horacio Castellanos Moya offers a provocative example of postwar cynicism in his 1997 novel "El asco: Thomas Bernhard en San Salvador." By telling the story of Edgardo Vega, an emigrant who returns to El Salvador in the mid-1990s after living in Canada for eighteen years, "El asco" represents the mass exodus…

Teachers' Cultural Autobiography as Means of Civic Professional Engagement

ERIC Educational Resources Information Center

Enache, Mihaela

2018-01-01

This article will present my autobiographical journey: from communism to capitalism, from the banking system and the pedagogy of the oppressed to problem-posing education. My personal experiences are seen as a way of emigrating internally and as part of the struggle through the process of self-actualisation and self-understanding. In effect, the…

Moneneheo and Naheverien: Cheyenne and Mennonite Sewing Circles, Convergences and Conflicts, 1890-1970

ERIC Educational Resources Information Center

Schmidt, Kimberly D.

2011-01-01

Swiss emigres and Mennonite missionaries Marie and Rodolphe Petter were welcomed into Cheyenne Chief Red Moon's band in Oklahoma. Away from the interference of other whites, they decided to live like their new neighbors and pitched a tipi before building a more substantial structure. There they continued their studies of the Cheyenne language and…

Fertility and Child Mortality: Issues in the Demographic Transition of a Migrant Population.

ERIC Educational Resources Information Center

Ben-Porath, Yoram

This paper reviews issues pertaining to the relationship between child mortality and fertility and examines the fertility-mortality relationship of women who emigrated to Israel from various countries in Asia, Africa, and Europe and continued child bearing in Israel. Data from the 1961 Israel census of population is used. Among issues addressed in…

From County Cork to New York: The Emigration of Megan O'Rourke (A Work of Historical Fiction).

ERIC Educational Resources Information Center

Social Education, 2000

2000-01-01

Presents the story of Megan O'Rourke and her family from their life in Ireland, the experience of living through the Great Irish Famine, and their journey to New York City. States that this is a work of historical fiction. Includes a glossary of terms, questions, and activities. (CMK)

Solving Conceptual and Perceptual Analogies with Virtual Reality among Kindergarten Children of Immigrant Families

ERIC Educational Resources Information Center

Passig, David; Schwartz, Timor

2014-01-01

Background: The ability to think analogically is central to the process of learning and understanding reality and there is a broad consensus among researchers that we can improve this ability. Immigrants who have emigrated from developing to developed countries tend to experience tremendous challenges in their early years as immigrants. Their…

Keepers of the Second Throat

ERIC Educational Resources Information Center

Smith, Patricia

2011-01-01

The author's mother, an emigrant, wanted to talk right before she dies and so attended a free English lesson in their community. She recalls her father as a great storyteller and because of him, she grew to think of the world in terms of the stories it could tell. She became addicted to unfolding drama, winding narrative threads, the lyricism of…

Family Dynamics and the Teenage Immigrant: Creating the Self through the Parents' Image.

ERIC Educational Resources Information Center

Markowitz, Fran

1994-01-01

Assessed role played by Soviet Jewish emigre family in exacerbating dual disjunctures of immigration and adolescents. Results, based on life history interviews with five women who came from United Soviet Socialist Republic to United States as teenagers in 1970s, challenge bipolar model of adolescent immigrants and raise questions about previous…

Language Testing, "Integration" and Subtractive Multilingualism in Italy: Challenges for Adult Immigrant Second Language and Literacy Education

ERIC Educational Resources Information Center

Love, Stephanie V.

2015-01-01

Since Italy's unification in 1861, the establishment and diffusion of the standard Italian language at the expense of all other linguistic varieties has dominated language and education policy discourses. Today, as Italy has transformed from a country of mass "emigration" to a country of mass "immigration," the language…

Distance Education in Guyana. Report of a Project Identification Consultancy. Consultant Report 3.

ERIC Educational Resources Information Center

Commonwealth of Learning, Vancouver (British Columbia).

Distance education is the only prospect of bringing further educational opportunities within the grasp of most adults in Guyana. Some factors that make distance education desirable, such as the infrastructure and present economic problems, militate against its provision. Many of the best educated personnel in all sectors have emigrated; the loss…

Increased orosomucoid in urine is an independent predictor of cardiovascular and all-cause mortality in patients with type 2 diabetes at 10 years of follow-up.

PubMed

Svendstrup, Mathilde; Christiansen, Merete Skovdal; Magid, Erik; Hommel, Eva; Feldt-Rasmussen, Bo

2013-01-01

To evaluate whether increased urinary orosomucoid excretion rate (UOER) is an independent predictor of cardiovascular and all-cause mortality in type 2 diabetes (T2DM) and type 1 diabetes (T1DM) at 10years of follow-up. We followed 430 patients with T2DM and 148 patients with T1DM until emigration, death or November 2011. We measured UOER levels in overnight urine samples. Descriptive data are given in the article. In patients with T2DM and T1DM, all-cause mortality (log-rank test, p<0.01 for both types) and cardiovascular mortality (log-rank test, p<0.01 for T2DM and p=0.04 for T1DM) were significantly higher in patients with increased UOER. Normoalbuminuric patients with T2DM and increased UOER levels had higher all-cause and cardiovascular mortality (log-rank test, p<0.01 for both types). UOER was independently predictive of all-cause (HR 1.52; 95% CI 1.10-2.09; p=0.01) and cardiovascular (HR 2.31; 95% CI 1.46-3.66; p<0.01) mortality in patients with T2DM, but not in patients with T1DM. UOER is an independent predictor of all-cause and cardiovascular mortality even in normoalbuminuric patients with T2DM at 10years of follow-up. Further studies are needed in order to evaluate the prognostic and clinical relevance. Copyright © 2013 Elsevier Inc. All rights reserved.

Improving size estimates of open animal populations by incorporating information on age

USGS Publications Warehouse

Manly, Bryan F.J.; McDonald, Trent L.; Amstrup, Steven C.; Regehr, Eric V.

2003-01-01

Around the world, a great deal of effort is expended each year to estimate the sizes of wild animal populations. Unfortunately, population size has proven to be one of the most intractable parameters to estimate. The capture-recapture estimation models most commonly used (of the Jolly-Seber type) are complicated and require numerous, sometimes questionable, assumptions. The derived estimates usually have large variances and lack consistency over time. In capture–recapture studies of long-lived animals, the ages of captured animals can often be determined with great accuracy and relative ease. We show how to incorporate age information into size estimates for open populations, where the size changes through births, deaths, immigration, and emigration. The proposed method allows more precise estimates of population size than the usual models, and it can provide these estimates from two sample occasions rather than the three usually required. Moreover, this method does not require specialized programs for capture-recapture data; researchers can derive their estimates using the logistic regression module in any standard statistical package.

Dispersal leads to spatial autocorrelation in species distributions: A simulation model

USGS Publications Warehouse

Bahn, V.; Krohn, W.B.; O'Connor, R.J.

2008-01-01

Compared to population growth regulated by local conditions, dispersal has been underappreciated as a central process shaping the spatial distribution of populations. This paper asks: (a) which conditions increase the importance of dispersers relative to local recruits in determining population sizes? and (b) how does dispersal influence the spatial distribution patterns of abundances among connected populations? We approached these questions with a simulation model of populations on a coupled lattice with cells of continuously varying habitat quality expressed as carrying capacities. Each cell contained a population with the basic dynamics of density-regulated growth, and was connected to other populations by immigration and emigration. The degree to which dispersal influenced the distribution of population sizes depended most strongly on the absolute amount of dispersal, and then on the potential population growth rate. Dispersal decaying in intensity with distance left close neighbours more alike in population size than distant populations, leading to an increase in spatial autocorrelation. The spatial distribution of species with low potential growth rates is more dependent on dispersal than that of species with high growth rates; therefore, distribution modelling for species with low growth rates requires particular attention to autocorrelation, and conservation management of these species requires attention to factors curtailing dispersal, such as fragmentation and dispersal barriers. ?? 2007 Elsevier B.V. All rights reserved.

Visions of America: Personal Narratives from the Promised Land. A Multicultural Anthology of Autobiography and Essay.

ERIC Educational Resources Information Center

Brown, Wesley, Ed.; Ling, Amy, Ed.

This anthology of personal narratives and excerpts from memoirs and autobiographies is seen as a companion to the earlier anthology, "Imagining America: Stories from the Promised Land." While focusing on nonfiction, this book continues the exploration of emigration to and migration within the United States in the 20th century. However, the scope…

Meloidogyne incognita emigration from cotton roots may be induced by the resistance QTL qMi-C11

USDA-ARS?s Scientific Manuscript database

Upland cotton (Gossypium hirsutum) is one of the most widely grown crops in the southern US, and Meloidogyne incognita is the most significant pathogen of cotton in the US. Two QTLs, qMi-C11 and qMi-C14, conferring resistance to M. incognita have been identified in cotton. Previous research docume...

In Search of Educational Equity for the Migrant Children of Shanghai

ERIC Educational Resources Information Center

Wang, Lihua; Holland, Tracey

2011-01-01

Around the world there is a growing consensus that migrant children's rights must be protected, regardless of where they have emigrated from. One of these rights is the right to a public education of equal quality to that granted to non-migrant children regardless of where one's family is registered or pays taxes. This article focuses on migrant…

A Longitudinal Approach to Great Plains Migration

ERIC Educational Resources Information Center

Hudson, John C.

2002-01-01

Students of population and regional studies are familiar with the demographic accounting equation in which the size of the population at time t + x is equal to the population at time t plus the births, minus the deaths, plus the immigrants, minus the emigrants, during the interval of time x. This simple formula can be used to derive a variety of…

Policy Responses to Address Student "Brain Drain": An Assessment of Measures Intended to Reduce the Emigration of Singaporean International Students

ERIC Educational Resources Information Center

Ziguras, Christopher; Gribble, Cate

2015-01-01

For several decades, Singapore has experienced a high rate of outbound degree mobility with around 1 in 10 higher education students currently studying outside the country according to UNESCO figures. Singapore's successful economic development strategy, which has seen it become a key Asian hub for knowledge-intensive industries for…

Victor or Villain? Wernher von Braun and the Space Race

ERIC Educational Resources Information Center

O'Brien, Jason L.; Sears, Christine E.

2011-01-01

Set during the Cold War and space race, this historical role-play focuses on Wernher von Braun's involvement in and culpability for the use of slave laborers to produce V-2 rockets for Nazi Germany. Students will grapple with two central questions. Should von Braun have been allowed to emigrate to the United States given his affiliation with the…

Measurement Units. Intercultural Educational Activities

ERIC Educational Resources Information Center

Magdas, Ioana

2009-01-01

Today's society is characterized by a plurality of cultures in such a way that a person will often interact and interrelate with new cultures. The situation becomes even more complicated when one has to adapt to a new culture for a short period of time (travel or study visit) or a long period of time (new work place, emigration etc.). Any…

Regionalism, Security and Cooperation in Oceania

DTIC Science & Technology

2015-06-01

storm damage). Potential second-order consequences include economic loss from these events, declining revenues from tourism , and emigration to escape... gover - nance, and political and economic structural reforms. Such confidence is boosted by China’s own developmental experiences and the positive...Cooperation in Oceania Introduction Australia, by dint of geography, trade and investment links, tourism , aid, defense assets and sport, has exercised a

Family Values: An Immigrant Teacher's Story

ERIC Educational Resources Information Center

Kayser, Abigail Akosua

2017-01-01

When Abigail Akosua Kayser and her parents emigrated from Ghana to the United States, her family received a less-than-warm welcome at the high school she attended as a student. Kayser later became an educator with the goal of making her classroom a safe and welcoming place for immigrant students and their families. In this article, she shares her…

Origins of the Discrimination Perceived by Mapuches in Chile Based on an Evaluation of Kimeltuwun

ERIC Educational Resources Information Center

Rapiman, Daniel Quilaqueo

2011-01-01

The aim of this article is to examine the origin of perceived discrimination as it appears in the discourse of Mapuches living in Temuco and Santiago, and how that discourse is related to the evaluation of "kimeltuwun" (educational knowledge). A qualitative design was used to survey Mapuche emigrants to these two urban centers, where…

How to Shape Children's Value Attitudes toward the Rural Way of Life

ERIC Educational Resources Information Center

Gur'ianova, M. P.

2011-01-01

The crisis of rural life in Russia involves a declining and aging population, emigration of rural young people to urban areas, lack of employment, and farms in urgent need of modernization. Programs in rural schools can be used more deliberately to encourage young people to remain in the village and to equip them to be agents of rural…

31 CFR 500.559 - Accounts of North Korean, North Vietnamese, Cambodian or South Vietnamese sole proprietorships.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Korea, North Viet-Nam, Cambodia, or South Viet-Nam if the proprietor has emigrated from those countries... licenses do not unblock any indebtedness of the proprietorship due to persons in North Korea, North Viet... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Accounts of North Korean, North...

The Coimbra Community Awareness Project (Portugal). The CDCC's Project No. 7: "The Education and Cultural Development of Migrants."

ERIC Educational Resources Information Center

Rey, Micheline

The Coimbra (Portugal) Community Awareness Project is intended to remedy the social problems caused by migration by helping a local community take responsibility for its own affairs, understand the interactions at work, and enable both residents and emigrants to benefit together from migration. The project operates at several levels under the…

Is the Exodus of Cadres out of Russian Science a Gain or a Loss?

ERIC Educational Resources Information Center

Naumova, T. V.

2010-01-01

Russian scientists lag behind others in both remuneration and working conditions, and this has led many of them to leave science for other occupations or to leave Russia. While the country may benefit when a scientist chooses to enter business or politics, both society and Russian science are negatively affected when scientists emigrate. In order…

Education and the Knowledge Military

DTIC Science & Technology

2010-04-01

residents emigrated from developing countries with undeveloped education systems and work in service related fields. They come to America for various...Cooperation and Development Countries (OECD) in a 2006 international assessment. 5 An increasingly diverse country , demographics are particularly important...seaboard of a country is one of its frontiers” and the easier the access to this frontier through deep water ports the greater the ability to

Rangers, Mounties, and the Subjugation of Indigenous Peoples, 1870-1885

ERIC Educational Resources Information Center

Graybill, Andrew R.

2004-01-01

During the 1840s and 1850s, more than 300,000 traders and overland emigrants followed the Platte and Arkansas rivers westward across the Central Plains, the winter habitat of the bison. By the mid-1870s indigenous peoples at both ends of the grasslands, in places such as the Texas Panhandle and the upper Missouri River valley, fiercely defended…

Polish Immigrant Children in the UK: Catholic Education and Other Aspects of "Migration Luck"

ERIC Educational Resources Information Center

Sadownik, Alicja R.; Mikiewicz, Piotr

2016-01-01

After 2005, approximately two million Poles emigrated, choosing mostly Britain as their destination. Quantitative reports paint a picture of the typical Polish immigrant as a person between the ages of 31-39, who, with a vocational (or equivalent) education, is active on the labor market. This paper reports on a qualitative study of six typical…

Cut to the chase: a review of CD26/dipeptidyl peptidase‐4's (DPP4) entanglement in the immune system

PubMed Central

Wagner, L.; Stephan, M.; von Hörsten, S.

2016-01-01

Summary CD26/DPP4 (dipeptidyl peptidase 4/DP4/DPPIV) is a surface T cell activation antigen and has been shown to have DPP4 enzymatic activity, cleaving‐off amino‐terminal dipeptides with either L‐proline or L‐alanine at the penultimate position. It plays a major role in glucose metabolism by N‐terminal truncation and inactivation of the incretins glucagon‐like peptide‐1 (GLP) and gastric inhibitory protein (GIP). In 2006, DPP4 inhibitors have been introduced to clinics and have been demonstrated to efficiently enhance the endogenous insulin secretion via prolongation of the half‐life of GLP‐1 and GIP in patients. However, a large number of studies demonstrate clearly that CD26/DPP4 also plays an integral role in the immune system, particularly in T cell activation. Therefore, inhibition of DPP4 might represent a double‐edged sword. Apart from the metabolic benefit, the associated immunological effects of long term DPP4 inhibition on regulatory processes such as T cell homeostasis, maturation and activation are not understood fully at this stage. The current data point to an important role for CD26/DPP4 in maintaining lymphocyte composition and function, T cell activation and co‐stimulation, memory T cell generation and thymic emigration patterns during immune‐senescence. In rodents, critical immune changes occur at baseline levels as well as after in‐vitro and in‐vivo challenge. In patients receiving DPP4 inhibitors, evidence of immunological side effects also became apparent. The scope of this review is to recapitulate the role of CD26/DPP4 in the immune system regarding its pharmacological inhibition and T cell‐dependent immune regulation. PMID:26919392

Pretransplant thymic function predicts acute rejection in antithymocyte globulin-treated renal transplant recipients.

PubMed

Bamoulid, Jamal; Courivaud, Cécile; Crepin, Thomas; Carron, Clémence; Gaiffe, Emilie; Roubiou, Caroline; Laheurte, Caroline; Moulin, Bruno; Frimat, Luc; Rieu, Philippe; Mousson, Christiane; Durrbach, Antoine; Heng, Anne-Elisabeth; Rebibou, Jean-Michel; Saas, Philippe; Ducloux, Didier

2016-05-01

Lack of clear identification of patients at high risk of acute rejection hampers the ability to individualize immunosuppressive therapy. Here we studied whether thymic function may predict acute rejection in antithymocyte globulin (ATG)-treated renal transplant recipients in 482 patients prospectively studied during the first year post-transplant of which 86 patients experienced acute rejection. Only CD45RA(+)CD31(+)CD4(+) T cell (recent thymic emigrant [RTE]) frequency (RTE%) was marginally associated with acute rejection in the whole population. This T-cell subset accounts for 26% of CD4(+) T cells. Pretransplant RTE% was significantly associated with acute rejection in ATG-treated patients (hazard ratio, 1.04; 95% confidence interval, 1.01-1.08) for each increased percent in RTE/CD4(+) T cells), but not in anti-CD25 monoclonal (αCD25 mAb)-treated patients. Acute rejection was significantly more frequent in ATG-treated patients with high pretransplant RTE% (31.2% vs. 16.4%) or absolute number of RTE/mm(3) (31.7 vs. 16.1). This difference was not found in αCD25 monclonal antibody-treated patients. Highest values of both RTE% (>31%, hazard ratio, 2.50; 95% confidence interval, 1.09-5.74) and RTE/mm(3) (>200/mm(3), hazard ratio, 3.71; 95% confidence interval, 1.59-8.70) were predictive of acute rejection in ATG-treated patients but not in patients having received αCD25 monoclonal antibody). Results were confirmed in a retrospective cohort using T-cell receptor excision circle levels as a marker of thymic function. Thus, pretransplant thymic function predicts acute rejection in ATG-treated patients. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Increased mortality in a Danish cohort of young people with Type 1 diabetes mellitus followed for 24 years.

PubMed

Sandahl, K; Nielsen, L B; Svensson, J; Johannesen, J; Pociot, F; Mortensen, H B; Hougaard, P; Broe, R; Rasmussen, M L; Grauslund, J; Peto, T; Olsen, B S

2017-03-01

To determine the mortality rate in a Danish cohort of children and adolescents diagnosed with Type 1 diabetes mellitus compared with the general population. In 1987 and 1989 we included 884 children and 1020 adolescents aged 20 years and under, corresponding to 75% of all Danish children and adolescents with Type 1 diabetes, in two nationwide studies in Denmark. Those who had participated in both investigations (n = 720) were followed until 1 January 2014, using the Danish Civil Registration System on death certificates and emigration. We derived the expected number of deaths in the cohort, using population data values from Statistics Denmark to calculate the standardized mortality ratio. Survival analysis was performed using Cox proportional hazards model. During the 24 years of follow-up, 49 (6.8%) patients died, resulting in a standardized mortality ratio of 4.8 (95% confidence interval 3.5, 6.2) compared with the age-standardized general population. A 1% increase in baseline HbA 1c (1989), available in 718 of 720 patients, was associated with all-cause mortality (hazard ratio = 1.38; 95% confidence interval 1.2, 1.6; P < 0.0001). Type 1 diabetes with multiple complications was the most common reported cause of death (36.7%). We found an increased mortality rate in this cohort of children and adolescents with Type 1 diabetes compared with the general population. The only predictor for increased risk of death up to 24 years after inclusion was the HbA 1c level in 1989. This emphasizes the importance of achieving optimal metabolic control in young people with Type 1 diabetes. © 2016 Diabetes UK.

Unauthorized Immigration to the United States: Annual Estimates and Components of Change, by State, 1990 to 2010

PubMed Central

Warren, Robert; Warren, John Robert

2013-01-01

We describe a method for producing annual estimates of the unauthorized immigrant population in the United Sates and components of population change, for each state and D.C., for 1990 to 2010. We quantify a sharp drop in the number of unauthorized immigrants arriving since 2000, and we demonstrate the role of departures from the population (emigration, adjustment to legal status, removal by the Department of Homeland Security (DHS), and deaths) in reducing population growth from one million in 2000 to population losses in 2008 and 2009. The number arriving in the U.S. peaked at more than one million in 1999 to 2001, and then declined rapidly through 2009. We provide evidence that population growth stopped after 2007 primarily because entries declined and not because emigration increased during the economic crisis. Our estimates of the total unauthorized immigrant population in the U.S. and in the top ten states are comparable to those produced by DHS and the Pew Hispanic Center. For the remaining states and D.C., our data and methods produce estimates with smaller ranges of sampling error. PMID:23956482

Seasonality in communication and collective decision-making in ants.

PubMed

Stroeymeyt, N; Jordan, C; Mayer, G; Hovsepian, S; Giurfa, M; Franks, N R

2014-04-07

The ability of animals to adjust their behaviour according to seasonal changes in their ecology is crucial for their fitness. Eusocial insects display strong collective behavioural seasonality, yet the mechanisms underlying such changes are poorly understood. We show that nest preference by emigrating Temnothorax albipennis ant colonies is influenced by a season-specific modulatory pheromone that may help tune decision-making according to seasonal constraints. The modulatory pheromone triggers aversion towards low-quality nests and enhances colony cohesion in summer and autumn, but not after overwintering-in agreement with reports that field colonies split in spring and reunite in summer. Interestingly, we show that the pheromone acts by downgrading the perceived value of marked nests by informed and naive individuals. This contrasts with theories of collective intelligence, stating that accurate collective decision-making requires independent evaluation of options by individuals. The violation of independence highlighted here was accordingly shown to increase error rate during emigrations. However, this is counterbalanced by enhanced cohesion and the transmission of valuable information through the colony. Our results support recent claims that optimal decisions are not necessarily those that maximize accuracy. Other criteria-such as cohesion or reward rate-may be more relevant in animal decision-making.

Estimating recruitment dynamics and movement of rainbow trout (Oncorhynchus mykiss) in the Colorado River in Grand Canyon using an integrated assessment model

USGS Publications Warehouse

Korman, Josh; Martell, Steven J.D.; Walters, Carl J.; Makinster, Andrew S.; Coggins, Lewis G.; Yard, Michael D.; Persons, William R.

2012-01-01

We used an integrated assessment model to examine effects of flow from Glen Canyon Dam, Arizona, USA, on recruitment of nonnative rainbow trout (Oncorhynchus mykiss) in the Colorado River and to estimate downstream migration from Glen Canyon to Marble Canyon, a reach used by endangered native fish. Over a 20-year period, recruitment of rainbow trout in Glen Canyon increased with the annual flow volume and when hourly flow variation was reduced and after two of three controlled floods. The model predicted that approximately 16 000 trout·year–1 emigrated to Marble Canyon and that the majority of trout in this reach originate from Glen Canyon. For most models that were examined, over 70% of the variation in emigration rates was explained by variation in recruitment in Glen Canyon, suggesting that flow from the dam controls in large part the extent of potential negative interactions between rainbow trout and native fish. Controlled floods and steadier flows, which were originally aimed at partially restoring conditions before the dam (greater native fish abundance and larger sand bars), appear to have been more beneficial to nonnative rainbow trout than to native fish.

Gender, Power, and Emigration From Mexico.

PubMed

Nobles, Jenna; McKelvey, Christopher

2015-10-01

The prevailing model of migration in developing countries conceives of a risk-diversifying household in which members act as a single entity when making migration decisions. Ethnographic studies challenge this model by documenting gender hierarchy in family decisions and arguing that, in many contexts, men and women have differing views on the value of migration. We assess these perspectives using longitudinal survey data from Mexico. We show that Mexican households are heterogeneous in terms of women's decision-making authority and control over resources, and this variation predicts the subsequent emigration of their male partners to the United States. We then use data from a policy experiment to demonstrate that an exogenous increase in a woman's control over household resources decreases the probability that her spouse migrates. Our findings support the presence of important gender differences in how migration is valued. They also suggest that women's role in these decisions is inadvertently underrepresented in studies of migrant families. Staying is also a migration decision, and it is more likely in homes in which women have greater authority. From a policy perspective, the results suggest that Mexican migration is influenced not only by increases in household resources but also by which members of the household control them.

Gender, Power, and Emigration From Mexico

PubMed Central

Nobles, Jenna; McKelvey, Christopher

2015-01-01

The prevailing model of migration in developing countries conceives of a risk-diversifying household in which members act as a single entity when making migration decisions. Ethnographic studies challenge this model by documenting gender hierarchy in family decisions and arguing that, in many contexts, men and women have differing views on the value of migration. We assess these perspectives using longitudinal survey data from Mexico. We show that Mexican households are heterogeneous in terms of women's decision-making authority and control over resources, and this variation predicts the subsequent emigration of their male partners to the United States. We then use data from a policy experiment to demonstrate that an exogenous increase in a woman's control over household resources decreases the probability that her spouse migrates. Our findings support the presence of important gender differences in how migration is valued. They also suggest that women's role in these decisions is inadvertently underrepresented in studies of migrant families. Staying is also a migration decision, and it is more likely in homes in which women have greater authority. From a policy perspective, the results suggest that Mexican migration is influenced not only by increases in household resources but also by which members of the household control them. PMID:26100982

The Education-Occupation Mismatch of International and Internal Migrants in Mexico, 2005-2012.

PubMed

Villarreal, Andrés

2016-06-01

Recent studies have found international migrants from developing countries such as Mexico to be negatively selected by education; that is, they are less educated than those who stay behind. Moving beyond the question of whether migrants are negatively selected by education overall, I examine how migrants are selected compared with others in similar jobs. Using data from a nationally representative panel survey of Mexican households, I find that men who migrate abroad have significantly higher levels of education than nonmigrants in the same occupation. Because men who are overeducated for their occupation tend to receive lower wages than those employed in occupations commensurate with their education, and are also more dissatisfied with their jobs, overeducation may encourage men to emigrate. Results from the regression models, which account for differential selectivity into employment, indicate that internal migrants within Mexico also have higher educational levels than nonmigrants in the same occupation prior to migrating but comparable levels of education afterward. Migrating internally, therefore, appears to allow men to improve their occupational placement. Finally, I examine changes in migrants' education over time and find evidence that the education-occupation mismatch has increased among Mexican emigrants in the years following the 2008 U.S. recession.

Seasonal migration to high latitudes results in major reproductive benefits in an insect

PubMed Central

Chapman, Jason W.; Bell, James R.; Burgin, Laura E.; Reynolds, Donald R.; Pettersson, Lars B.; Hill, Jane K.; Bonsall, Michael B.; Thomas, Jeremy A.

2012-01-01

Little is known of the population dynamics of long-range insect migrants, and it has been suggested that the annual journeys of billions of nonhardy insects to exploit temperate zones during summer represent a sink from which future generations seldom return (the “Pied Piper” effect). We combine data from entomological radars and ground-based light traps to show that annual migrations are highly adaptive in the noctuid moth Autographa gamma (silver Y), a major agricultural pest. We estimate that 10–240 million immigrants reach the United Kingdom each spring, but that summer breeding results in a fourfold increase in the abundance of the subsequent generation of adults, all of which emigrate southward in the fall. Trajectory simulations show that 80% of emigrants will reach regions suitable for winter breeding in the Mediterranean Basin, for which our population dynamics model predicts a winter carrying capacity only 20% of that of northern Europe during the summer. We conclude not only that poleward insect migrations in spring result in major population increases, but also that the persistence of such species is dependent on summer breeding in high-latitude regions, which requires a fundamental change in our understanding of insect migration. PMID:22927392

Patterns of larval sucker emigration from the Sprague and lower Williamson Rivers of the Upper Klamath Basin, Oregon, after the removal of Chiloquin Dam - 2009-10 Annual Report

USGS Publications Warehouse

Ellsworth, Craig M.; Martin, Barbara A.

2012-01-01

Data presented in this report is a continuation of a research project that began in 2004. Larval drift parameters measured in 2009 and 2010 were similar to those measured from 2004 to 2008. Most larvae and eggs were collected at the two drift sites downstream of the former Chiloquin Dam (river kilometer 0.7 on the Sprague River and river kilometer 7.4 on the Williamson River). Mean and peak sample densities increased with proximity to Upper Klamath Lake. Peak larval densities continued to be collected between 1 and 3 hours after sunset at Chiloquin, which is the drift site nearest a known spawning area. Catch distribution of larvae and eggs in the lower Sprague and Williamson Rivers suggests that most SNS and LRS spawning continues to occur downstream of the site of the former Chiloquin Dam. The sizes and growth stages indicate that larval emigration from spawning areas resulting from drift occurs within a few days after swim-up. Larval suckers appear to move downstream quickly until they reach suitable rearing habitat.

Evolution of complex density-dependent dispersal strategies.

PubMed

Parvinen, Kalle; Seppänen, Anne; Nagy, John D

2012-11-01

The question of how dispersal behavior is adaptive and how it responds to changes in selection pressure is more relevant than ever, as anthropogenic habitat alteration and climate change accelerate around the world. In metapopulation models where local populations are large, and thus local population size is measured in densities, density-dependent dispersal is expected to evolve to a single-threshold strategy, in which individuals stay in patches with local population density smaller than a threshold value and move immediately away from patches with local population density larger than the threshold. Fragmentation tends to convert continuous populations into metapopulations and also to decrease local population sizes. Therefore we analyze a metapopulation model, where each patch can support only a relatively small local population and thus experience demographic stochasticity. We investigated the evolution of density-dependent dispersal, emigration and immigration, in two scenarios: adult and natal dispersal. We show that density-dependent emigration can also evolve to a nonmonotone, "triple-threshold" strategy. This interesting phenomenon results from an interplay between the direct and indirect benefits of dispersal and the costs of dispersal. We also found that, compared to juveniles, dispersing adults may benefit more from density-dependent vs. density-independent dispersal strategies.

Behavioural response of Phytoseiulus persimilisin inert materials for technical application.

PubMed

Wendorf, Dennis; Sermann, Helga; Katz, Peter; Lerche, Sandra; Büttner, Carmen

2009-01-01

A large scale application of the predatory mite Phytoseiulus persimilis Athias-Henriot for use in the biological control of spider mites in the field requires testing the behaviour of Phytoseiulus persimilis in inert materials, like millet pelts and Vermiculite (1-3 mm). In laboratory studies, the distribution of the individuals in such materials, the time of remaining in the material were proved. To examine the abiotic influences on the time of remaining in the material, the dampness of the materials was varied (0%, 5% and 10%). Moreover, the influence of attitude of materials was tested. The time of emigration from the material was noted for each individual. Emigration from all dry materials was completed 15 minutes at the latest after set up of the mites. The increase of dampness had an obvious effect on the time of remaining in the material. In this respect the material millet pelts showed the most favourable effect with 10% dampness. Increasing attitude of material the mobility of predatory mites will be influenced negatively above 75 cm. Up to 50 cm, mites have not a problem to move in the material and the time of remaining can be prolonged considerably.

Candida albicans induces selective development of macrophages and monocyte derived dendritic cells by a TLR2 dependent signalling.

PubMed

Yáñez, Alberto; Megías, Javier; O'Connor, José-Enrique; Gozalbo, Daniel; Gil, M Luisa

2011-01-01

As TLRs are expressed by haematopoietic stem and progenitor cells (HSPCs), these receptors may play a role in haematopoiesis in response to pathogens during infection. We have previously demonstrated that in in vitro defined conditions inactivated yeasts and hyphae of Candida albicans induce HSPCs proliferation and differentiation towards the myeloid lineage by a TLR2/MyD88 dependent pathway. In this work, we showed that C. albicans invasive infection with a low virulence strain results in a rapid expansion of HSPCs (identified as LKS cells: Lin(-) c-Kit(+) Sca-1(+) IL-7Rα(-)), that reach the maximum at day 3 post-infection. This in vivo expansion of LKS cells in TLR2(-/-) mice was delayed until day 7 post- infection. Candidiasis was, as expected, accompanied by an increase in granulopoiesis and decreased lymphopoiesis in the bone marrow. These changes were more pronounced in TLR2(-/-) mice correlating with their higher fungal burden. Accordingly, emigration of Ly6C(high) monocytes and neutrophils to spleen was increased in TLR2(-/-) mice, although the increase in macrophages and inflammatory macrophages was completely dependent on TLR2. Similarly, we detected for the first time, in the spleen of C. albicans infected control mice, a newly generated population of dendritic cells that have the phenotype of monocyte derived dendritic cells (moDCs) that were not generated in TLR2(-/-) infected mice. In addition, C. albicans signalling through TLR2/MyD88 and Dectin-1 promotes in vitro the differentiation of Lin(-) cells towards moDCs that secrete TNF-α and are able to kill the microorganism. Therefore, our results indicate that during infection C. albicans can directly stimulate progenitor cells through TLR2 and Dectin-1 to generate newly formed inflammatory macrophages and moDCs that may fulfill an essential role in defense mechanisms against the pathogen.

Candida albicans Induces Selective Development of Macrophages and Monocyte Derived Dendritic Cells by a TLR2 Dependent Signalling

PubMed Central

Yáñez, Alberto; Megías, Javier; O'Connor, José-Enrique; Gozalbo, Daniel; Gil, M. Luisa

2011-01-01

As TLRs are expressed by haematopoietic stem and progenitor cells (HSPCs), these receptors may play a role in haematopoiesis in response to pathogens during infection. We have previously demonstrated that in in vitro defined conditions inactivated yeasts and hyphae of Candida albicans induce HSPCs proliferation and differentiation towards the myeloid lineage by a TLR2/MyD88 dependent pathway. In this work, we showed that C. albicans invasive infection with a low virulence strain results in a rapid expansion of HSPCs (identified as LKS cells: Lin− c-Kit+ Sca-1+ IL-7Rα−), that reach the maximum at day 3 post-infection. This in vivo expansion of LKS cells in TLR2−/− mice was delayed until day 7 post- infection. Candidiasis was, as expected, accompanied by an increase in granulopoiesis and decreased lymphopoiesis in the bone marrow. These changes were more pronounced in TLR2−/− mice correlating with their higher fungal burden. Accordingly, emigration of Ly6Chigh monocytes and neutrophils to spleen was increased in TLR2−/− mice, although the increase in macrophages and inflammatory macrophages was completely dependent on TLR2. Similarly, we detected for the first time, in the spleen of C. albicans infected control mice, a newly generated population of dendritic cells that have the phenotype of monocyte derived dendritic cells (moDCs) that were not generated in TLR2−/− infected mice. In addition, C. albicans signalling through TLR2/MyD88 and Dectin-1 promotes in vitro the differentiation of Lin− cells towards moDCs that secrete TNF-α and are able to kill the microorganism. Therefore, our results indicate that during infection C. albicans can directly stimulate progenitor cells through TLR2 and Dectin-1 to generate newly formed inflammatory macrophages and moDCs that may fulfill an essential role in defense mechanisms against the pathogen. PMID:21935459

Decreases in thymopoiesis of astronauts returning from space flight

PubMed Central

Benjamin, Cara L.; Stowe, Raymond P.; St. John, Lisa; Sams, Clarence F.; Mehta, Satish K.; Crucian, Brian E.; Pierson, Duane L.

2016-01-01

Following the advent of molecular assays that measure T cell receptor excision circles (TRECs) present in recent thymic emigrants, it has been conclusively shown that thymopoiesis persists in most adults, but that functional output decreases with age, influencing the maintenance of a diverse and functional T cell receptor (TCR) repertoire. Space flight has been shown to result in a variety of phenotypic and functional changes in human T cells and in the reactivation of latent viruses. While space flight has been shown to influence thymic architecture in rodents, thymopoiesis has not previously been assessed in astronauts. Here, we assessed thymopoiesis longitudinally over a 1-year period prior to and after long-term space flight (median duration, 184 days) in 16 astronauts. While preflight assessments of thymopoiesis remained quite stable in individual astronauts, we detected significant suppression of thymopoiesis in all subjects upon return from space flight. We also found significant increases in urine and plasma levels of endogenous glucocorticoids coincident with the suppression of thymopoiesis. The glucocorticoid induction and thymopoiesis suppression were transient, and they normalized shortly after return to Earth. This is the first report to our knowledge to prospectively demonstrate a significant change in thymopoiesis in healthy individuals in association with a defined physiologic emotional and physical stress event. These results suggest that suppression of thymopoiesis has the potential to influence the maintenance of the TCR repertoire during extended space travel. Further studies of thymopoiesis and endogenous glucocorticoids in other stress states, including illness, are warranted. PMID:27699228

Some issues in Middle Eastern international migration.

PubMed

Sirageldin, I

1983-01-01

2 controversial issues related to the consequences of Middle Eastern international migration were examined: its effect on the development policies of the labor importing countries with a special reference to the case of Kuwait; and its effect on the growth potential of the labor exporting countries with special reference to recent development in Egypt's agricultural reproductivity. A preliminary note comments on the analytical nature of international labor migration in the Middle East and on the public view of emigrants as export commodities. The basic parameters of a desired population parity are interrelated. It is possible to influence the labor ratio (R2) as well as the nonKuwait crude labor participation rate (R3) through a migration policy. Thus, given a policy objective of some desired balance stated in trms of 1 or more of the identified parameters, it is possible to analyze the consequences of alternative migration strategies. It is important to consider the role of relative productivity (R6). An attempt to change R6 has implications for both the design of a migration policy and a national policy of human capital formation. Other factors may not be immediately related to a migration policy. The question then is whether these ratios are sensitive to policy intervention. In a simulation exercise it was assumed that the Kuwaiti crude labor force participation rate (R4) will increase by 13% during a period of 10 years. R4 increases if relatively more people work. Women are 1 segment of the labor force that is not adequately represented, partly because of traditions, lack of skills, and the presence of high fertility. None of these can change in the short run without an active policy of social reform. Yet, the assumption seems to be in the right direction. A policy that attempts to reduce R4 through increasing fertility in Kuwait is clearly against the tide. In sum, the labor importing countries faced with recent unfavorable demographic realities will actively develop population policies that are consistent with their socioeconomic plans. The flow of labor immigration is a tool that can be manipulated on relatively short notice, and the economic cost of such a policy is relatively simple to estimate. In examining labor exporting countries, the focus is narrowed to 1 sector (agriculture) and with 1 issue their emigration behavior are being blamed simultaneously for the decline of the agricultural sector. Some hypotheses are offered. Clearly, emigration in the case of Egyptian agriculture must be evaluated in terms of the gross benefit of remittances and in terms of their effect on local production in the short-and longterm. It seems that population and development policies must take care of the effect of emigration on agricultural productivity through 2 channels: the effect of remittances on expenditure and labor market behavior; and its effect on fertility behavior.

Evaluation of trap capture in a geographically closed population of brown treesnakes on Guam

USGS Publications Warehouse

Tyrrell, C.L.; Christy, M.T.; Rodda, G.H.; Yackel Adams, A.A.; Ellingson, A.R.; Savidge, J.A.; Dean-Bradley, K.; Bischof, R.

2009-01-01

1. Open population mark-recapture analysis of unbounded populations accommodates some types of closure violations (e.g. emigration, immigration). In contrast, closed population analysis of such populations readily allows estimation of capture heterogeneity and behavioural response, but requires crucial assumptions about closure (e.g. no permanent emigration) that are suspect and rarely tested empirically. 2. In 2003, we erected a double-sided barrier to prevent movement of snakes in or out of a 5-ha semi-forested study site in northern Guam. This geographically closed population of >100 snakes was monitored using a series of transects for visual searches and a 13 ?? 13 trapping array, with the aim of marking all snakes within the site. Forty-five marked snakes were also supplemented into the resident population to quantify the efficacy of our sampling methods. We used the program mark to analyse trap captures (101 occasions), referenced to census data from visual surveys, and quantified heterogeneity, behavioural response, and size bias in trappability. Analytical inclusion of untrapped individuals greatly improved precision in the estimation of some covariate effects. 3. A novel discovery was that trap captures for individual snakes consisted of asynchronous bouts of high capture probability lasting about 7 days (ephemeral behavioural effect). There was modest behavioural response (trap happiness) and significant latent (unexplained) heterogeneity, with small influences on capture success of date, gender, residency status (translocated or not), and body condition. 4. Trapping was shown to be an effective tool for eradicating large brown treesnakes Boiga irregularis (>900 mm snout-vent length, SVL). 5. Synthesis and applications. Mark-recapture modelling is commonly used by ecological managers to estimate populations. However, existing models involve making assumptions about either closure violations or response to capture. Physical closure of our population on a landscape scale allowed us to determine the relative importance of covariates influencing capture probability (body size, trappability periods, and latent heterogeneity). This information was used to develop models in which different segments of the population could be assigned different probabilities of capture, and suggests that modelling of open populations should incorporate easily measured, but potentially overlooked, parameters such as body size or condition. ?? 2008 The Authors.

Human Capital and the Brain Drain Phenomenon: A Study of the Immigration and Emigration of Canada's Knowledge Workers

ERIC Educational Resources Information Center

Della Savia, Roy

2003-01-01

This research discusses the relationship between the migration of skilled professional and managerial workers from Canada to the United States, the so called "brain drain," and seeks to determine if and how the Canada-U.S. Free Trade Agreement (F.T.A.) and the North American Free Trade Agreement (NAFTA) may have affected bilateral flows…

Bridging Literacy Practices through Storytelling, Translanguaging, and an Ethnographic Partnership: A Case Study of Dominican Students at Bronx Community College

ERIC Educational Resources Information Center

Parmegiani, Andrea

2014-01-01

This article reports on my attempt to use storytelling as an entry point into academic discourse in a learning community designed to meet the learning needs of ESL students who recently emigrated from the Dominican Republic. Based on research suggesting a correlation between academic success in a second language and first language literacy skills,…

Older Chinese women immigrants and their leisure experiences: before and after emigration to the United States

Treesearch

Ching-Hua Ho; Jaclyn A. Card

2002-01-01

The concept of leisure has generally focused on men. This is especially true in Chinese society where women seldom have the right to speak about leisure or mention leisure activities. For many Chinese women, the integration of household and leisure has been necessary to find meaning in life. Based on this concept, we explored older Chinese women immigrants'...

Photographs as Political Statements: A Case Study of Picture Editing in the German Illustrated Press and Its Impact on American Picture Magazines, 1926-38.

ERIC Educational Resources Information Center

Ohrn, Karin B.

A comparison of photographs in four German magazines published from 1926 to 1933 with photographs appearing in "Fortune" and "Life" from 1930 to 1938 reveals specific patterns and techniques by German photographers, who later emigrated to the United States, that served as models for "Life" and for subsequent American…

The Connecticut-Haitian Connection: Development and Educational Exchanges between the Caribbean and New England. Area Studies Resource Guides Number Nine.

ERIC Educational Resources Information Center

Colman, Rosalie Marson; And Others

The Connecticut Haitian American community has recently become large enough and sufficiently well established to develop programs to assist economic and educational development in the Republic of Haiti. Southern Connecticut became a destination for large numbers of Haitian emigrants and political refugees in the 1950s, in 1964, and again in 1971.…

Long-distance dispersal of spruce budworm (Choristoneura fumiferana Clemens) in Minnesota (USA) and Ontario (Canada) via the atmospheric pathway

Treesearch

Brian R. Sturtevant; Gary L. Achtemeier; Joseph J. Charney; Dean P. Anderson; Barry J. Cooke; Phillip A. Townsend

2013-01-01

Dispersal can play an important role in the population dynamics of forest insects, but the role of long-distance immigration and emigration remains unclear due to the difficulty of quantifying dispersal distance and direction. We designed an agent-based spruce budworm flight behavior model that, when interfaced with temperature, wind speed, and precipitation output...

Plus Ca Change, Plus C'Est La Meme Chose: Attitudes towards English Language Learning in Hong Kong--Frederick Stewart's Evidence.

ERIC Educational Resources Information Center

Bickley, Gillian

1990-01-01

Suggests that the attitudes of the people of Hong Kong toward learning English, during both an earlier period and at present, are similar and deeply entrenched. The increasing emigration of Hong Kong people, mainly to Anglophone countries, makes an international understanding of the attitude of Hong Kong people toward learning English very…

First Language Attrition in the Speech of Dutch-English Bilinguals: The Case of Monozygotic Twin Sisters

ERIC Educational Resources Information Center

Mayr, Robert; Price, Sacha; Mennen, Ineke

2012-01-01

Recent years have seen a proliferation of research on attrition in L1 speech (de Leeuw, Mennen & Scobbie, in press; de Leeuw, Schmid & Mennen, 2010; Dmitrieva, Jongman & Sereno, 2010; Mennen, 2004). Adding to this line of inquiry, the present study investigates the speech of a 62-year-old bilingual monozygotic twin who emigrated to an L2-speaking…

[Wilhelm Liepmann (1878-1939)--the fate of a gynecologist between the Kaiser Reich and Fascism].

PubMed

Schneck, P

1984-01-01

The paper gives a bioergographical survey on the German obstetrician and gynaecologist Wilhelm Liepmann. He was Ass. Professor at the Berlin university. Later he became director of the German Women-Institute, which was founded by the Hauptverband der Krankenkassen. In 1933 Liepmann had to emigrate to Turkey, where he got the chair of gynaecology at the university of Istanbul.