Transnational migration and the redefinition of the state: Variations and explanations

In this article, we examine the shifting policies of sending country states towards communities living abroad, demonstrate the ways in which these are redefining the relationship between the state and its territorial boundaries, and highlight how these reconfigure conventional understandings of sovereignty, citizenship and membership. We begin by delineating the ­different types of policies that sending states are adapting in order to break down categories like "global nations policies" and to identify similarities and differences between states. We then suggest some possible explanations both for the convergence we see on the "repertoire" of policies that states employ and divergence we see in how far states are willing to go to ensure that migrants remain enduring long-distance membership. We draw on material from several countries, but look most closely at Brazil, Mexico, the Dominican Republic and Haiti.     

Conclusion: Towards a new world - the origins and effects of transnational activities

The preceding set of articles is reviewed with a focus on the forces affecting the rise and character of grass-roots transnationalism and its effects in countries of origin and destination. The increasing visibility of the phenomenon has led to recent attacks based on its alleged disintegrative consequences for the host society and culture. From a review of the evidence in this volume and the recent literature on immigrant adaptation, I conclude that the opposite is the case. Implications of findings presented in this collection for official policies towards transnationalism and the latter's effect on sending countries are examined.     

Terrains of blood and nation: Haitian transnational social fields

As have a growing number of political leaders of emigrant-sending countries, Haitian government officials and immigrant leaders have envisioned Haiti as a transnational nation-state. This article explores the ways in which the vision of Haiti as a transnational nation builds upon the experiences, needs and aspirations of both persons living in Haiti and those who have settled in the United States. Using a concept of 'transnational social field', we examine how family obligations and the experiences of immigration are understood through a language of blood and descent that links individuals to broader concepts of a transnational homeland. Rather than celebrating transnational connections, this essay concludes by warning that the ideologies which undergird 'long distance nationalism' are problematic.     

Strategic citizens of America: transnational inequalities and transformation of citizenship

This article analyses the process whereby ‘natural' citizens of one country mobilize their resources so that their children receive by birthright, the citizenship of a rich liberal democracy. Utilizing the case of Turkish upper classes, who give birth in the USA in order to benefit from the jus soli principle, we trace the emergence of new inequalities at the intersection of multiple citizenship regimes. We show that, by mobilizing resources in markets of health care, travel, and real estate, those with means can acquire US citizenship for their children in expectation of future benefits. Because they are able to access ‘valuable' citizenships, these actors can strategically combine privileges within nation states with inequalities between citizenship regimes at the global level for the children. Their differential access to citizenship enhances the gate-keeping functions of citizenship. Based on these observations, we draw an analogy between citizenship and property regimes, understood broadly.     

Transnational drifters or hyperspace dwellers: an exploration of the lives of Filipino seafarers aboard and ashore

This article considers seafarers as transnational actors in the global economy. It is based on research undertaken as part of an ESRC/Seafarers International Research Centre [SIRC] funded project. The study utilized on-board participant observation and depth interviews to explore the lives of seafarers sailing on ships with multinational crews. In addition depth interviews were conducted with seafarers who have settled in port cities such as Rotterdam and Hamburg. Here the article investigates the extent to which such seafarers are embedded in their 'host' societies and examines the links they maintain with their 'homes' by exploring their networks, social relationships, patterns of communication, remittance habits, and investment strategies.     

The effects of energy input,immigration and habitat size on food web structure: a microcosm experiment

It has been hypothesised that larger habitats should support more complex food webs. We consider three mechanisms which could lead to this pattern. These are increased immigration rates, increased total productivity and spatial effects on the persistence of unstable interactions. Experiments designed to discriminate between these mechanisms were carried out in laboratory aquatic microcosm communities of protista and bacteria, by independently manipulating habitat size, total productivity and immigration rate. Larger habitats supported more complex food webs, with more species, more links per species and longer maximum and mean food chains, even in the absence of differences in total energy input. Increased immigration rate resulted in more complex food webs, but habitats with higher energy input per unit area supported less complex food webs. We conclude that spatial effects on the persistence of unstable interactions, and variation in immigration rates, are plausible mechanisms by which habitat size could affect food web structure. Variation in total productivity with habitat area seems a less likely explanation for variation in food web structure.     

A review of current large‐scale mouse knockout efforts

After the successful completion of the human genome project (HGP), biological research in the postgenome era urgently needs an efficient approach for functional analysis of genes. Utilization of knockout mouse models has been powerful for elucidating the function of genes as well as finding new therapeutic interventions for human diseases. Gene trapping and gene targeting are two independent techniques for making knockout mice from embryonic stem (ES) cells. Gene trapping is high‐throughput, random, and sequence‐tagged while gene targeting enables the knockout of specific genes. It has been about 20 years since the first gene targeting and gene trapping mice were generated. In recent years, new tools have emerged for both gene targeting and gene trapping, and organizations have been formed to knock out genes in the mouse genome using either of the two methods. The knockout mouse project (KOMP) and the international gene trap consortium (IGTC) were initiated to create convenient resources for scientific research worldwide and knock out all the mouse genes. Organizers of KOMP regard it as important as the HGP. Gene targeting methods have changed from conventional gene targeting to high‐throughput conditional gene targeting. The combined advantages of trapping and targeting elements are improving the gene trapping spectrum and gene targeting efficiency. As a newly‐developed insertional mutation system, transposons have some advantages over retrovirus in trapping genes. Emergence of the international knockout mouse consortium (IKMP) is the beginning of a global collaboration to systematically knock out all the genes in the mouse genome for functional genomic research. genesis 48:73–85, 2010. © 2010 Wiley‐Liss, Inc.     

P-glycoprotein as multidrug transporter: a critical review of current multidrug resistant cell lines

MDR has been studied extensively in mammalian cell lines. According to usual practice, the MDR phenotype is characterized by the following features: cross resistance to multiple chemotherapeutic agents (lipophilic cations), defective intracellular drug accumulation and retention, overexpression of P-gp (often accompanied by gene amplification), and reversal of the phenotype by addition of calcium channel blockers. An hypothesis for the function of P-gp has been proposed in which P-gp acts as a carrier protein that actively extrudes MDR compounds out of the cells. However, basic questions, such as what defines the specificity of the pump and how is energy for active efflux transduced, remain to be answered. Furthermore, assuming that P-gp acts as a drug transporter, one will expect a relationship between P-gp expression and accumulation defects in MDR cell lines. A review of papers reporting 97 cell lines selected for resistance to the classical MDR compounds has revealed that a connection exists in most of the reported cell lines. However, several exceptions can be pointed out. Furthermore, only a limited number of well characterized series of sublines with different degrees of resistance to a single agent have been reported. In many of these, a correlation between P-gp expresson and transport properties can not be established. Co-amplification of genes adjacent to the mdr1 gene, mutations [122], splicing of mdr1 RNA [123], modulation of P-gp by phosphorylation [124] or glycosylation [127], or experimental conditions [26,78] could account for some of the complexity of the phenotype and the absence of correlation in some of the cell lines. However, both cell lines with overexpression of P-gp without increased efflux [i.e., 67,75] and cell lines without P-gp expression and accumulation defects/increased efflux [i.e., 25,107] have been reported. Thus, current results from MDR cell lines contradict - but do not exclude - that P-gp acts as multidrug transporter. Other models for the mechanism of resistance have been proposed: (1) An energy-dependent permeability barrier working with greater efficacy in resistant cells. This hypothesis is supported by studies of influx which, although few, all except one demonstrate decreased influx in resistant cells; (2) Resistant cells have a greater endosomal volume, and a greater exocytotic activity accounts for the efflux. Furthermore, large amounts of P-gp in the plasma membrane altering the ultrastructure and generalized changes, such as increases or decreases in membrane fluidity, alterations in lipid composition, changes in transmembrane pH gradient and membrane potential have been described in MDR cell lines and could account for some of the findings.     

Threshold behaviour of a SIR epidemic model with age structure and immigration

We consider a SIR age-structured model with immigration of infectives in all epidemiological compartments; the population is assumed to be in demographic equilibrium between below-replacement fertility and immigration; the spread of the infection occurs through a general age-dependent kernel. We analyse the equations for steady states; because of immigration of infectives a steady state with a positive density of infectives always exists; however, a quasi-threshold theorem is proved, in the sense that, below the threshold, the density of infectives is close to 0, while it is away from 0, above the threshold; furthermore, conditions that guarantee uniqueness of steady states are obtained. Finally, we present some numerical examples, inspired by the Italian demographic situation, that illustrate the threshold-like behaviour, and other features of the stationary solutions and of the transient. Supported in part by FIRB project RBAU01K7M2 “Metodi dell’Analisi Matematica in Biologia, Medicina e Ambiente” of the Italian Ministero Istruzione Università e Ricerca     

Female choice of sexually antagonistic male adaptations: a critical review of some current research

We contrast some recent uses of the concept of male-female conflict, with the type of conflict that is inherent in traditional Darwinian female choice. Females in apparent conflict situations with males may suffer reduced lifetime reproduction, but nevertheless benefit because they obtain sons with superior manipulative abilities. Female defences against male manipulations may not be 'imperfect' because of inability to keep pace with male evolution, but in order to screen males and favour those that are especially good manipulators. We examine the consequences of these ideas, and of the difficulties of obtaining biologically realistic measures of female costs, for some recent theoretical and empirical presentations of male-female conflict ideas, and find that male-female conflict in the new sense is less certain than has been commonly supposed. Disentangling previous sexual selection ideas and the new conflict of interest models will probably often be difficult, because the two types of payoffs are not mutually exclusive.     

P-glycoprotein as multidrug transporter: a critical review of current multidrug resistant cell lines.

MDR has been studied extensively in mammalian cell lines. According to usual practice, the MDR phenotype is characterized by the following features: cross resistance to multiple chemotherapeutic agents (lipophilic cations), defective intracellular drug accumulation and retention, overexpression of P-gp (often accompanied by gene amplification), and reversal of the phenotype by addition of calcium channel blockers. An hypothesis for the function of P-gp has been proposed in which P-gp acts as a carrier protein that actively extrudes MDR compounds out of the cells. However, basic questions, such as what defines the specificity of the pump and how is energy for active efflux transduced, remain to be answered. Furthermore, assuming that P-gp acts as a drug transporter, one will expect a relationship between P-gp expression and accumulation defects in MDR cell lines. A review of papers reporting 97 cell lines selected for resistance to the classical MDR compounds has revealed that a connection exists in most of the reported cell lines. However, several exceptions can be pointed out. Furthermore, only a limited number of well characterized series of sublines with different degrees of resistance to a single agent have been reported. In many of these, a correlation between P-gp expression and transport properties can not be established. Co-amplification of genes adjacent to the mdr1 gene, mutations [122], splicing of mdr1 RNA [123], modulation of P-gp by phosphorylation [124] or glycosylation [127], or experimental conditions [26,78] could account for some of the complexity of the phenotype and the absence of correlation in some of the cell lines. However, both cell lines with overexpression of P-gp without increased efflux [i.e., 67,75] and cell lines without P-gp expression and accumulation defects/increased efflux [i.e., 25,107] have been reported. Thus, current results from MDR cell lines contradict--but do not exclude--that P-gp acts as multidrug transporter. Other models for the mechanism of resistance have been proposed: (1) An energy-dependent permeability barrier working with greater efficacy in resistant cells. This hypothesis is supported by studies of influx which, although few, all except one demonstrate decreased influx in resistant cells; (2) Resistant cells have a greater endosomal volume, and a greater exocytotic activity accounts for the efflux.(ABSTRACT TRUNCATED AT 400 WORDS)     

工业生态学的内涵与发展

作为一门发展不到20a的综合性交叉学科,工业生态学目前需要界定其学术范畴和理论基础.首先评述了工业生态学的4个主要领域:(1)社会代谢是工业生态学起源最早也是发展最为成熟的领域.它提供了宏观层次上观察和测量经济发展与物质流动关系的方法和工具,但需要进一步细化物质流动图景和加强流动机制的解释;(2)工业共生是工业生态学最具特征的领域.它实质上是人们出于观察视角的转变而对工业体系的重新认识.逻辑严谨且规则统一的解释框架有助于工业共生理论的发展和实践;(3)基础设施与产业相互选择且协同演进,二者共同构成了城市的物质基础,而城市又是更大范围内区域经济系统的子集.这一组工业生态学的研究对象需要处理产业全球化与社会和生态要素本土化的矛盾;(4)工业发展的可持续性是工业生态学关注的核心目标,而多样性和复杂性给其研究带来了很大的挑战.这提醒我们要避免陷入简单化、还原论或机械论的陷阱,多开展实证研究.最后,从本体论、方法论和隐喻3个标准给出了工业生态学的初步界定,并指出4个重要的努力方向.     

How normative debates about immigration shape analyses of the assimilation processes of second-generation youth: lessons from Spanish Legacies

In Spanish Legacies, Portes, Aparicio, and Haller offer the results of their longitudinal study on the assimilation of the children of immigrants in Spanish society. Thanks to their study design, which parallels the earlier Children of Immigrants Longitudinal Study conducted by Portes and Rumbaut, the authors are able to compare assimilation trajectories in Spain with those of second-generation youth in the United States. This comparison raises important considerations about how immigration policy shapes assimilation processes. More centrally, the contrast between the cases invites a deeper consideration of normative questions that not only undergird immigration policy but also shape the assimilation experiences of the second generation. The juxtaposition of the two cases also elicits provocations about how the sociological theories about assimilation might have been different if they had been developed based on the Spanish, rather than the American, experience, and how those Spanish-inflected theories might support different directions of inquiry.     

Remediation of dyes in textile effluent: a critical review on current treatment technologies with a proposed alternative

The control of water pollution has become of increasing importance in recent years. The release of dyes into the environment constitutes only a small proportion of water pollution, but dyes are visible in small quantities due to their brilliance. Tightening government legislation is forcing textile industries to treat their waste effluent to an increasingly high standard. Currently, removal of dyes from effluents is by physio-chemical means. Such methods are often very costly and although the dyes are removed, accumulation of concentrated sludge creates a disposal problem. There is a need to find alternative treatments that are effective in removing dyes from large volumes of effluents and are low in cost, such as biological or combination systems. This article reviews the current available technologies and suggests an effective, cheaper alternative for dye removal and decolourisation applicable on large scale.     

Bone morphogenetic proteins: a critical review

Bone Morphogenetic Proteins (BMPs) are potent growth factors belonging to the Transforming Growth Factor Beta superfamily. To date over 20 members have been identified in humans with varying functions during processes such as embryogenesis, skeletal formation, hematopoesis and neurogenesis. Though their functions have been identified, less is known regarding levels of regulation at the extracellular matrix, membrane surface, and receptor activation. Further, current models of activation lack the integration of these regulatory mechanisms. This review focuses on the different levels of regulation, ranging from the release of BMPs into the extracellular components to receptor activation for different BMPs. It also highlights areas in research that is lacking or contradictory.     

Hyperhidrosis: a review of current management

Primary hyperhidrosis is a troublesome disorder of excessive perspiration that affects as much as 1 percent of the population. Sufferers are usually young and are often affected by related social, professional, and psychological problems. Many methods for treating hyperhidrosis exist; however, no single treatment is without its weakness or complications. This article aims to clarify the issues related to the use of each treatment modality, including the most recently proposed method using botulinum toxin.     

Speciation through competition: a critical review

We examined causes of speciation in asexual populations in both sympatry and parapatry, providing an alternative explanation for the speciation patterns reported by Dieckmann and Doebeli (1999) and Doebeli and Dieckmann (2003). Both in sympatry and parapatry, they find that speciation occurs relatively easily. We reveal that in the sympatric clonal model, the equilibrium distribution is continuous and the disruptive selection driving evolution of discrete clusters is only transient. Hence, if discrete phenotypes are to remain stable in the sympatric sexual model, there should be some source of nontransient disruptive selection that will drive evolution of assortment. We analyze sexually reproducing populations using the Bulmer's infinitesimal model and show that cost-free assortment alone leads to speciation and disruptive selection only arises when the optimal distribution cannot be matched--in this example, because the phenotypic range is limited. In addition, Doebeli and Dieckmann's analyses assumed a high genetic variance and a high mutation rate. Thus, these theoretical models do not support the conclusion that sympatric speciation is a likely outcome of competition for resources. In their parapatric model (Doebeli and Dieckmann 2003), clustering into distinct phenotypes is driven by edge effects, rather than by frequency-dependent competition.     

Back-calculation of fish length: a critical review

A review is made of the literature on the back-calculation of fish body length from marks on scales or other hard parts (otoliths, vertebrae, fin rays, etc.). Though the technique is widely used it does not appear to be well understood. Regression methods are commonly used, apparently in ignorance of the more realistic proportional methods. It is not generally recognized that there are two equally plausible back-calculation hypotheses which can lead to significantly different back-calculated lengths. The Fraser-Lee equation, the most commonly used back-calculated formula, follows neither of these hypotheses but is based on a misuse of linear regression. It is recommended that back-calculation be restricted to procedures following one of the proportional hypotheses; that the difference between lengths calculated using the two hypotheses is a useful measure of the minimum uncertainty in back-calculation lengths; and that more attention be paid to validating back-calculation hypotheses by comparing observed and back-calculated lengths for individual fish. The pattern of heteroscedasticity in body length–scale radius plots is noted as a useful diagnostic in evaluating back-calculation hypothesis.     

Clinical disorders of fibrinolysis: a critical review

Much progress has recently been made in understanding the biochemistry and physiology of endogenous fibrinolysis. As a result, a better understanding of the mechanisms and clinical consequences of disordered fibrinolysis has emerged. Increased fibrinolytic activity is an uncommon but important cause of hemorrhagic disease. Congenital disorders of fibrinolysis which cause bleeding include increased plasma plasminogen activator activity and deficiency of alpha-2 antiplasmin. Acquired disorders associated with increased fibrinolytic activity and bleeding include liver cirrhosis, amyloidosis, acute promyelocytic leukemia, some solid tumors, and certain snake envenomation syndromes. Increased fibrinolysis is important to recognize because epsilon-aminocaproic acid (EACA) may be required to prevent or control bleeding. Diminished fibrinolytic activity has been associated with a variety of thrombotic disorders, but a direct cause-and-effect relationship has yet to be established. Congenital abnormalities of fibrinolysis associated with thrombosis include plasminogen deficiency, decreased endothelial generation of plasminogen activator activity, and certain abnormal fibrinogens. Thrombosis in these disorders is effectively managed with warfarin. Diminished fibrinolysis has also been reported in "idiopathic" venous thrombosis, oral contraceptive-induced and post-operative venous thrombosis, coronary artery disease, cerebrovascular disease, systemic lupus erythematosus, and thrombotic thrombocytopenic purpura, but the significance of abnormal fibrinolysis in these disorders is uncertain. Large, prospective studies of fibrinolytic variables as risk factors for vascular and thrombotic disease are needed to determine whether pharmacologic augmentation of impaired fibrinolysis could be useful in the prevention or treatment of these disorders.     

Trichloroethylene and dichloroethylene: a critical review of teratogenicity

Trichloroethylene (TCE) and dichloroethylene (DCE) are high-volume industrial chemicals frequently found as contaminants in public drinking water supplies. The developmental toxicity of both chemicals has been evaluated in laboratory and epidemiologic studies. It has been suggested that TCE and DCE are specific cardiac teratogens and that drinking water contaminated with them increases the risk of congenital heart defects in exposed human populations. In contrast, other laboratory and epidemiologic studies do not find an increase in developmental effects, either in general or specifically affecting the heart. This laboratory and epidemiologic base was reviewed to evaluate the strengths and weaknesses of the conflicting published reports. We conclude that the weight of experimental and epidemiologic evidence does not support the hypothesis that TCE or DCE is a selective developmental toxicant in general or a cardiac teratogen specifically.