Exclusive recognition: against reductionism and distortion

This article analyses two dominant discourses of racial politics in Hawai'i and the work they do naturalizing haole (white people or whiteness in Hawai'i) in the islands. The first is the well-worn discourse of racial harmony representing Hawai'i as an idyllic racial paradise with no conflict or inequality. Frequently contrasting the islands with the ‘racist mainland’, this discourse circulates among many communities and is widely referenced. There is also a competing discourse of discrimination against non-locals which contends that haoles and non-local people of colour are disrespected and treated unfairly in Hawai'i. As negative referents for each other, these discourses work to reinforce one another and are historically linked. I suggest that the question of racial politics be reframed towards consideration of the processes of racialization themselves – towards a new way of thinking about racial politics in Hawai'i that breaks free of the not racist/racist dyad.     

Dry land drowning or rip current survival? Haitians without status in the Bahamas

Recent scholarship contends that collective action emerges when human rights are violated. This article investigates why Haitians without status in the Bahamas have yet to mobilize collectively for basic rights and protections, despite discrimination and exploitation. The article examines two analogies to explain their immobilization. The analogy of dry land drowning utilizes Goffman's Stigma (1963) framework to describe how social prejudice hinders the ability of Haitians without status to act, while the analogy of rip current survival explains how institutional drawbacks pull Haitians without status away from movement activity through a political process analysis. The article contends that both interpretations are inadequate when taken alone and provides suggestions for future research into Bahamian-Haitian relations.     

Latino racial choices: the effects of skin colour and discrimination on Latinos’ and Latinas’ racial self-identifications

Abstract

Are predictions that Hispanics will make up 25 per cent of the US population in 2050 reliable? The authors of this paper argue that these and other predictions are problematic insofar as they do not account for the volatile nature of Latino racial and ethnic identifications. In this light, the authors propose a theoretical framework that can be used to predict Latinos’ and Latinas’ racial choices. This framework is tested using two distinct datasets – the 1989 Latino National Political Survey and the 2002 National Survey of Latinos. The results from the analyses of both of these surveys lend credence to the authors’ claims that Latinas’ and Latinos’ skin colour and experiences of discrimination affect whether people from Latin America and their descendants who live in the US will choose to identify racially as black, white or Latina/o.     

DNase I and Proteinase K eliminate DNA from injured or dead bacteria but not from living bacteria in microbial reference systems and natural drinking water biofilms for subsequent molecular biology analyses

Molecular techniques, such as polymerase chain reaction (PCR) and quantitative PCR (qPCR), are very sensitive, but may detect total DNA present in a sample, including extracellular DNA (eDNA) and DNA coming from live and dead cells. DNase I is an endonuclease that non-specifically cleaves single- and double-stranded DNA. This enzyme was tested in this study to analyze its capacity of digesting DNA coming from dead cells with damaged cell membranes, leaving DNA from living cells with intact cell membranes available for DNA-based methods. For this purpose, an optimized DNase I/Proteinase K (DNase/PK) protocol was developed. Intact Staphylococcus aureus cells, heat-killed Pseudomonas aeruginosa cells, free genomic DNA of Salmonella enterica, and a mixture of these targets were treated according to the developed DNase/PK protocol. In parallel, these samples were treated with propidium monoazide (PMA) as an already described assay for live-dead discrimination. Quantitative PCR and PCR-DGGE of the eubacterial 16S rDNA fragment were used to test the ability of the DNase/PK and PMA treatments to distinguish DNA coming from cells with intact cell membranes in the presence of DNA from dead cells and free genomic DNA. The methods were applied to three months old autochthonous drinking water biofilms from a pilot facility built at a German waterworks. Shifts in the DNA patterns observed after DGGE analysis demonstrated the applicability of DNase/PK as well as of the PMA treatment for natural biofilm investigation. However, the DNase/PK treatment demonstrated some practical advantages in comparison with the PMA treatment for live/dead discrimination of bacterial targets in drinking water systems.     

Age differences in tactile pattern recognition at the fingertip

Young (21–26 years, n?=?20) and old (55–86 years, n?=?25) participants were tested for their ability to recognize raised letters (6-mm high, 1-mm relief) by touch. Spatial resolution thresholds were also measured with grating domes to derive an index of the degree of afferent innervation at the fingertip. Letter recognition in the young group was very consistent and highly accurate (mean, 86% correct), contrasting with the performance of the old group, which was more variable and comparatively low in accuracy (mean, 53% correct). In both groups, spatial resolution thresholds accounted for a substantial portion of the variance in the performance, suggesting a strong link between age-dependent variations in tactile innervation and recognition accuracy. The patterns of errors in the old group showed that an inability to encode internal elements specific to certain letters was at the source of most confusion among letters. Whether this inability reflected only deficient peripheral encoding mechanisms or some other alterations at the central level is discussed.     

Multicoloured greenbeards,bacteriocin diversity and the rock‐paper‐scissors game

Greenbeard genes identify copies of themselves in other individuals and cause their bearer to behave nepotistically towards those individuals. Bacterial toxins (bacteriocins) exemplify the greenbeard effect because producer strains carry closely linked genes for immunity, such that toxicity is limited to nonproducer strains. Bacteriocin producers can be maintained in a dynamic polymorphism, known as rock‐paper‐scissors (RPS) dynamics, with immune and susceptible strains. However, it is unclear whether and how such dynamics will be maintained in the presence of multiple toxin types (multiple beard ‘colours’). Here, we analyse strain dynamics using models of recurrent patch colonization and population growth. We find that (i) polymorphism is promoted by a small number of founding lineages per patch, strong local resource competition and the occurrence of mutations; (ii) polymorphism can be static or dynamic, depending on the intensity of local interactions and the costs of toxins and immunity; (iii) the occurrence of multiple toxins can promote RPS dynamics; and (iv) strain diversity can be maintained even when toxins differ in toxicity or lineages can exhibit multitoxicity/multi‐immunity. Overall, the factors that maintain simple RPS dynamics can also promote the coexistence of multiple toxin types (multiple beard colours), thus helping to explain the remarkable levels of bacteriocin diversity in nature. More generally, we contrast these results with the maintenance of marker diversity in genetic kin recognition.     

Giant clams discriminate threats along a risk gradient and display varying habituation rates to different stimuli

It is often beneficial for animals to discriminate between different threats and to habituate to repeated exposures of benign stimuli. While much is known about risk perception in vertebrates and some invertebrates, risk perception in marine invertebrates is less extensively studied. One method to study risk perception is to habituate animals to a series of exposures to one stimulus, and then present a novel stimulus to test if it transfers habituation. Transfer of habituation is seen as a continued decrease in response while lack of transfer is seen either by having a similar or greater magnitude response. We asked whether giant clams (Tridacna maxima) discriminate between biologically relevant types of threats along a risk gradient. Giant clams retract their mantle and close their shell upon detecting a threat. While closed, they neither feed nor photosynthesize, and prior work has shown that the cost of being closed increases as the duration of their response increases. We recorded a clam's latency to emerge after simulated threats chosen to represent a risk gradient: exposure to a small shading event, a medium shading event, a large shading event (chosen to simulate fish swimming above them), tapping on their shell and touching their mantle (chosen to simulate different degrees of direct attack). Although these stimuli are initially perceived as threatening, we expected clams to habituate to them because they are ultimately non‐damaging and it would be costly for clams to remain closed for extended periods of time when there is no threat present. Clams had different initial latencies to emerge and different habituation rates to these treatments, and they did not transfer habituation to higher risk stimuli and to some lower risk stimuli. These results suggest that clams discriminated between these stimuli along a risk gradient and the lack of habituation transfer shows that the new stimulus was perceived as a potential threat. This study demonstrates that sessile bivalves can discern between levels of predatory threat. These photosynthetic clams may benefit from being able to categorize predator cues for efficient energy allocation.