The "Other" Story of Model Minorities: Korean American High School Dropouts in an Urban Context

This article analyzes how socioeconomic backgrounds, social capital, and school resources affect Korean American youths' educational attainment and aspirations. In the context of limited social and economic support, students delineate differences within coethnic communities along class lines and adopt an oppositional cultural frame of reference to endure and resist institutional barriers. This study demonstrates the significance of distinguishing socioeconomic differences within Korean American communities and for whom the enclaves may be more beneficial.     

Mimicry between unequally defended prey can be parasitic: evidence for quasi-Batesian mimicry

The nature of signal mimicry between defended prey (known as Müllerian mimicry) is controversial. Some authors assert that it is always mutualistic and beneficial, whilst others speculate that less well defended prey may be parasitic and degrade the protection of their better defended co-mimics (quasi-Batesian mimicry). Using great tits (Parus major) as predators of artificial prey, we show that mimicry between unequally defended co-mimics is not mutualistic, and can be parasitic and quasi-Batesian. We presented a fixed abundance of a highly defended model and a moderately defended dimorphic (mimic and distinct non-mimetic) species, and varied the relative frequency of the two forms of the moderately defended prey. As the mimic form increased in abundance, per capita predation on the model-mimic pair increased. Furthermore, when mimics were rare they gained protection from predation but imposed no co-evolutionary pressure on models. We found that the feeding decisions of the birds were affected by their individual toxic burdens, consistent with the idea that predators make foraging decisions which trade-off toxicity and nutrition. This result suggests that many prey species that are currently assumed to be in a simple mutualistic mimetic relationship with their co-mimic species may actually be engaged in an antagonistic co-evolutionary process.     

Discrimination and ejection of eggs and nestlings by the fan-tailed gerygone from New Caledonia

Nestling rejection is a rare type of host defense against brood parasitism compared with egg rejection. Theoretically, host defenses at both egg and nestling stages could be based on similar underlying discrimination mechanisms but, due to the rarity of nestling rejector hosts, few studies have actually tested this hypothesis. We investigated egg and nestling discrimination by the fan-tailed gerygone Gerygone flavolateralis, a host that seemingly accepts nonmimetic eggs of its parasite, the shining bronze-cuckoo Chalcites lucidus, but ejects mimetic parasite nestlings. We introduced artificial eggs or nestlings and foreign gerygone nestlings in gerygone nests and compared begging calls of parasite and host nestlings. We found that the gerygone ejected artificial eggs only if their size was smaller than the parasite or host eggs. Ejection of artificial nestlings did not depend on whether their color matched that of the brood. The frequency of ejection increased during the course of the breeding season mirroring the increase in ejection frequency of parasite nestlings by the host. Cross-fostered gerygone nestlings were frequently ejected when lacking natal down and when introduced in the nest before hatching of the foster brood, but only occasionally when they did not match the color of the foster brood. Begging calls differed significantly between parasite and host nestlings throughout the nestling period. Our results suggest that the fan-tailed gerygone accepts eggs within the size range of gerygone and cuckoo eggs and that nestling discrimination is based on auditory and visual cues other than skin color. This highlights the importance of using a combined approach to study discrimination mechanisms of hosts.     

Multilevel Control of Organelle DNA Sequence Length in Plants

We have compared the length of noncoding organelle DNA spacers in a broad sample of plant species characterized by different life history traits to test hypotheses regarding the nature of the mechanisms driving changes in their size. We first demonstrate that the spacers do not evolve at random in size but have experienced directional evolutionary trends during plant diversification. We then study the relationships between spacer lengths and other molecular features and various species attributes by taking into account population genetic processes acting within cell lineages. Comparative techniques are used to test these relationships while controlling for species phylogenetic relatedness. The results indicate that spacer length depends on mode of organelle transmission, on population genetic structure, on nucleotide content, on rates of molecular evolution, and on life history traits, in conformity with predictions based on a model of intracellular competition among replicating organelle genomes. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Ophiostoma novo-ulmi sp. nov., causative agent of current Dutch elm disease pandemics

The aggressive subgroup of the Dutch elm disease pathogen Ophiostoma ulmi (Buism.) Nannf. syn. Ceratocystis ulmi (Buism.) Moreau is named as a new species, O. novo-ulmi, and is thereby separated from the old non-aggressive subgroup, which is retained as O. ulmi. O. novo-ulmi differs from O. ulmi in colony morphology, growth rate, optimum temperature for growth, perithecial neck length, pathogenicity to elm, bark colonising ability, cerato-ulmin protein production, synnemetal and protoperithecial production, mating type frequency, protein and isozyme polymorphisms, mitochondrial DNA and nuclear DNA polymorphisms, and mitochondrial DNA size. In addition, a strong unidirectional fertility barrier operates between the two species, while their hybrids show remarkable variation, poor fitness, and many are infertile. These aspects are summarised. New information on perithecial dimensions is presented. O. ulmi is redefined and a neotype designated. The status of the Eurasian and North American races of O. novo-ulmi is currently under investigation.Abbreviations EAN Eurasian race - NAN North American race     

Genetic races associated with the genera and sections of host species in the holoparasitic plant Cytinus (Cytinaceae) in the Western Mediterranean basin

* Speciation via race formation is an important evolutionary process in parasites, producing changes that favour their development on particular host species. Here, the holoparasitic plant Cytinus, which has diverse host species in the family Cistaceae, has been used to study the occurrence of such races. * Amplified fragment length polymorphism (AFLP) analyses were performed on 174 individuals of 22 populations parasitizing 10 Cistaceae species in the Western Mediterranean basin. * Neighbour-joining, multivariate ordination analyses, and individual-based Bayesian analyses, clustered Cytinus populations into five well-characterized genetic races that, overall, agreed with the taxonomic sections of their hosts. In the AMOVA, among-races differences accounted for almost 50% of the genetic variation. The isolation-by-distance model was not supported by a Mantel test among Cytinus populations (r = 0.012; P = 0.456). All races showed low within-population genetic diversity, probably as a result of restricted pollen flow aggravated by flowering asynchrony, restricted seed dispersion, or stochastic processes. * The genetic differentiation among the five races of Cytinus is congruent with the view that these races are well-characterized lineages that have evolved independently as a result of selective pressures imposed by their hosts. This pattern, with genetically distinctive groups associated with the infrageneric sections of the host species, has not been reported previously for parasitic angiosperms.     

Paradigms and Politics: Shaping Health Care Access for Sickle Cell Patients Through the Discursive Regimes of Biomedicine

The emergence of two different sickle cell disease and disease/treatment paradigms in two clinics, Children's Hospital West (CHW) and Children's Hospital East (CHE), demonstrates how physicians can influence institutional regimes of truth to improve patient access. Physicians at both clinics, far from simply acquiescing to dominant biomedical paradigms, recognize that their paradigms are in part rhetorical strategies designed to subvert problematic staff biases and perceptions, and to encourage a particular "self-efficacy" ethic in the patients. This paper positions physicians as struggling within the discursive regimes of biomedicine to create an institutional space where the disease and the sickle cell patient matter, and where patients comply with the performative rules of that space. This paper explores how physicians, patients, and institutions collaborate in the construction of sickle cell disease in such a way that biomedicine becomes a plural, as opposed to a singular and oppressive, discursive regime.     

Multilocus models of sympatric speciation: Bush versus Rice versus Felsenstein

Abstract. In populations of phytophagous insects that use the host plant as a rendezvous for mating, divergence in host preference could lead to sympatric speciation. Speciation requires the elimination of "generalist" genotypes, that is, those with intermediate host preference. This could occur because such genotypes have an inherent fitness disadvantage, or because preference alleles become associated with alleles that are oppositely selected on the two hosts. Although the former mechanism has been shown to be plausible, the latter mechanism has not been studied in detail. I consider a multilocus model (the "Bush model") in which one set of biallelic loci affects host preference, and a second set affects viability on the hosts once chosen. Alleles that increase viability on one host decrease viability on the other, and all loci are assumed to be unlinked. With moderately strong selection on the viability loci, preference alleles rapidly become associated with viability alleles, and the population splits into two reproductively isolated host specialist populations. The conditions for speciation to occur in this model, as measured by the strength of selection required, are somewhat more stringent than in a model in which preference and viability are controlled by the same loci (one-trait model). In contrast, the conditions are much less stringent than in a model in which speciation requires buildup of associations between viability loci and loci controlling a host-independent assortative mating trait (canonical two-trait model). Moreover, in the one-trait model, and to a lesser extent the Bush model, the strength of selection needed to initiate speciation is only slightly greater than that needed to complete it. This indicates that documenting instances of sympatric species that are reproductively isolated only by host or habitat preference would provide evidence for the plausibility of sympatric speciation in nature.     

Challenges to Consensus in Preparing the Supplement to the Surgeon General's Report on Mental Health

Preparing the Supplement to the Surgeon General's Report on Mental Health proved controversial because the assignment, by its nature, challenged several forms of consensus that typically remain unexamined. They included disciplinary assumptions about theory and methods, sociopolitical assumptions about the relevance of history to contemporary circumstances of ethnic minority groups in America, the rigor and usefulness of cultural formulation, and whether the burden of proof rested with those who took for granted that sociocultural differences exist in theories of behavior, or those who took for granted the existence of universals. Preparation of the Supplement illustrates the uncertainty and tension that arise when unexamined boundaries and perspectives lose their capacity to serve as guides to scientific judgment and discourse.     

Sociologists,Archbishops, and ‘making a verb of a noun’

ABSTRACT

Contemporary discussion about race has a tendency to set off out without first checking the rear view mirror. In Theories of Race and Ethnicity: Contemporary Debates and Perspectives, in contrast, Murji and Solomos identify what has and has not been covered, and so appeal at the outset for a ‘more sustained’ account of changing research agendas of race and ethnic relations. Taken as a whole, the collection allows the editors to contemplate ‘what factors explain the mobilizing power of ideas about race and ethnicity in the contemporary environment?' and whether indeed ‘it is the “real” rather than race that should be placed in quotation marks’.