Phenotype-environment correlations in a putative whitefish adaptive radiation

1. The adaptive radiation of fishes into benthic (littoral) and pelagic (lentic) morphs in post-glaciallakes has become an important model system for speciation. Although these systems are well stud-ied, there is little evidence of the existence of morphs that have diverged to utilize resources in theremaining principal lake habitat, the profundal zone.
2. Here, we tested phenotype-environment correlations of three whitefish (Coregonus lavaretus)morphs that have radiated into littoral, pelagic and profundal niches in northern Scandinavianlakes. We hypothesized that morphs in such trimorphic systems would have a morphology adaptedto one of the principal lake habitats (littoral, pelagic or profundal niches). Most whitefish popula-tions in the study area are formed by a single (monomorphic) whitefish morph, and we furtherhypothesized that these populations should display intermediate morphotypes and niche utiliza-tion. We used a combination of traditional (stomach content, habitat use, gill raker counts) andmore recently developed (stable isotopes, geometric morphometrics) techniques to evaluate pheno-type-environment correlations in two lakes with trimorphic and two lakes with monomorphicwhitefish.
3. Distinct phenotype-environment correlations were evident for each principal niche in whitefishmorphs inhabiting trimorphic lakes. Monomorphic whitefish exploited multiple habitats, hadintermediate morphology, displayed increased variance in gillraker-counts, and relied significantlyon zooplankton, most likely due to relaxed resource competition.
4. We suggest that the ecological processes acting in the trimorphic lakes are similar to each other,and are driving the adaptive evolution of whitefish morphs, possibly leading to the formation ofnew species.

Arsenic contamination in wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) on abandoned mine sites in southwest Britain

Arsenic can be highly toxic to mammals but there is relatively little information on its transfer to and uptake by free-living small mammals. The aim of this study was to determine whether intake and accumulation of arsenic by wild rodents living in arsenic-contaminated habitats reflected environmental levels of contamination and varied between species, sexes and age classes. Arsenic concentrations were measured in soil, litter, wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) from six sites which varied in the extent to which they were contaminated. Arsenic residues on the most contaminated sites were three and two orders of magnitude above background in soil and litter, respectively. Arsenic concentrations in the stomach contents, liver, kidney and whole body of small mammals reflected inter-site differences in environmental contamination. Wood mice and bank voles on the same sites had similar concentrations of arsenic in their stomach contents and accumulated comparable residues in the liver, kidney and whole body. Female bank voles, but not wood mice, had significantly higher stomach content and liver arsenic concentrations than males. Arsenic concentration in the stomach contents and body tissues did not vary with age class. The bioaccumulation factor (ratio of arsenic concentration in whole body to that in the diet) in wood mice was not significantly different to that in bank voles and was 0.69 for the two species combined, indicating that arsenic was not bioconcentrated in these rodents. Overall, this study has demonstrated that adult and juvenile wood mice and bank voles are exposed to and accumulate similar amounts of arsenic on arsenic-contaminated mine sites and that the extent of accumulation depends upon the level of habitat contamination.

The religious content of ethnic identities

The religious dimensions of ethnic identities have been under-theorized. In contemporary industrial societies there is a tendency to characterize religiously demarcated groups as 'really' ethnic.This article suggests that the religious content of ethnic boundaries may be more important than might initially be assumed. A religious identification may have specific religious content and assumptions that may cause it to operate in different ways from other identities. Even if identities do not seem primarily religious per se, they may have latent religious dimensions that can become reactivated. Whilst identity conflicts and other social struggles may stimulate the return of the religious, once reactivated, the religious dimensions of identity may take on a logic of their own.Therefore, the article argues that in many contexts there is a two-way relationship between religion and ethnicity. Each can stimulate the other, rather than religion simply playing a supporting role to the ethnic centrepiece.

Inositol 1,4,5-trisphosphate receptors modulate Ca2+ sparks and Ca2+ store content in vas deferens myocytes.

Spontaneous Ca2+ sparks were observed in fluo 4-loaded myocytes from guinea pig vas deferens with line-scan confocal imaging. They were abolished by ryanodine (100 microM), but the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) blockers 2-aminoethoxydiphenyl borate (2-APB; 100 microM) and intracellular heparin (5 mg/ml) increased spark frequency, rise time, duration, and spread. Very prolonged Ca2+ release events were also observed in approximately 20% of cells treated with IP3R blockers but not under control conditions. 2-APB and heparin abolished norepinephrine (10 microM; 0 Ca2+)-evoked Ca2+ transients but increased caffeine (10 mM; 0 Ca2+) transients in fura 2-loaded myocytes. Transients evoked by ionomycin (25 microM; 0 Ca2+) were also enhanced by 2-APB. Ca2+ sparks and transients evoked by norepinephrine and caffeine were abolished by thimerosal (100 microM), which sensitizes the IP3R to IP3. In cells voltage clamped at -40 mV, spontaneous transient outward currents (STOCs) were increased in frequency, amplitude, and duration in the presence of 2-APB. These data are consistent with a model in which the Ca2+ store content in smooth muscle is limited by tonic release of Ca2+ via an IP3-dependent pathway. Blockade of IP3Rs elevates sarcoplasmic reticulum store content, promoting Ca2+ sparks and STOC activity.

A content analysis method to measure critical thinking in face-to-face and computer supported group learning

This paper gives a detailed account of the content analysis method developed at Queen's University Belfast to measure critical thinking during group learning, as used in our controlled comparisons between learning in face-to-face and computer conference seminars. From Garrison's 5 stages of critical thinking, and Henri's cognitive skills needed in CMC, we have developed two research instruments: a student questionnaire and this content analysis method. The content analysis relies on identifying, within transcripts, examples of indicators of obviously critical and obviously uncritical thinking, from which several critical thinking ratios can be calculated.