Phylogenetic Distribution and Mechanism of Translocation Inhibition by Chilling

Lang, A. and Minchin, P. E. H. 1986. Phylogenetic distributionand mechanism of translocation inhibition by chilling.—J.exp. Bot. 37: 389–398 A standard chilling treatment was applied to a short lengthof thc translocation path of a range of plants (86 species representativeof 50, mostly angiosperm, families) and sensitivity of the translocationprocess assessed. In all dicotyledons, but only in 30% of monocotyledons,translocation was temporanly and reversibly inhibited by chilling. Our findings emphasize that inhibition of translocation by pathwaychilling should not be assumed to occur in all species. Studies,therefore, which employ pathway chilling as a device for temporarilymodifying patterns of assimilate flow must include a carefulexamination of the translocation behaviour of the species beingused under the precise treatment conditions imposed. This hasnot always been done in the past. Although sensitivity is possibly correlated with the phylogeneticdistribution of p-protein, the response to chilling is moreplausibly explained as a perturbation of membrane function thanas a blocking and unbiocking of sieve plate pores. Key words: Chilling, Translocation, Phylogcny     

Systematic notes on some British Ascophora (Bryozoa: Cheilostomata)

A review of the British ascophoran cheilostomes has revealed several instances of synonymic confusion, and necessitated the introduction of two new generic names. Porelloides gen. nov. is instituted for two species formerly included in Porella , with P. laevis (Fleming) as type species, and Phaceostachys gen. nov. is introduced for Lepralia spinifera Johnson. Smittoidea amplissima sp. nov. was hitherto not distinguished from Smittina landsborovii (Johnston). Porella minuta (Norman), reported from localities as far afield as the western Mediterranean and the Canadian Arctic, is shown to comprise two species, and the northern records are here attributed to P. alba Nordgaard. Exharella labiosa (Busk) and E. klugei sp. nov. (=E. ventricosa var. peristomata Kluge) are redescribed, and E. laqueata and E. abyssicola are discussed. The case for retaining Cellepora Linnaeus is argued and Lepralia quincuncialis Norman is referred to Buskea Heller.     

Revision of diplectanid monogeneans (Monopisthocotylea, Diplectanidae) in sillaginid fishes, with a description of a new species of Monoplectanum

Five species of diplectanids are described or redescribed on the basis of sclerotised parts, from a survey of 26 species of Sillaginidae in the Indo-west Pacific. Diplectanum sillagonum Tripathi is widespread, and is recorded on Sillago sihama from tropical Australia north to Hong Kong and west to India, as well as on S. vincenti (in India) and S. attenuata (Persian Gulf). Diplectanum blairense Gupta & Khanna infects S. sihama and S. indica and is sympatric with D. sillagonum over some of its range (Hong Kong to India and south to Bali). Diplectanum flagritubus Nagibina is synonymised with D. blairense. Diplectanum puriense Tripathi is redescribed from S. chondropus in western Thailand, but was not found on specimens of its type host, Sillaginopsis panijus from the Bay of Bengal. Monoplectanum youngi sp. n. is described from Sillago analis, S. ciliata, S. sihama, S. parvisquamis, S. lutea and S. attenuata and is more widespread than D. sillagonum , extending into subtropical waters in Australia. Monoplectanum australe Young infects S. maculata and S. burrus , and appears to be endemic to Australia. The diagnosis of Monoplectanum , until now monotypic, is emended, the genus is unlikely to contain more new species on sillaginid fishes, and its two species probably share a common ancestor with D. blairense. Parasitological evidence favours a close relationship between Sillaginidae and Sciaenidae.     

Do stream macroinvertebrates use instream refugia in response to severe short-term flow reduction in New Zealand streams?

1. Demand for water is increasing and water managers need to know how much they can remove from a stream before there are significant detrimental effects on its biological integrity. Flow reduction alters a number of habitat variables known to be important to aquatic invertebrates such as depth, velocity, temperature and fine sediment accumulation. Some taxa may attempt to use instream refugia to mitigate the effects of flow reduction.
2. We experimentally manipulated flows by constructing weirs and diversions in three small New Zealand streams. Discharge was reduced by 88–96%. We tested the hypothesis that macroinvertebrates would use pools and the hyporheic zone as refugia during short-term (1-month) periods of reduced flow.
3. We sampled hyporheic invertebrates with colonization chambers and pool invertebrates with kick nets within a before-after, control-impact (BACI) experimental design. A suite of physicochemical parameters was measured concurrently including surface and hyporheic temperatures.
4. Flow reduction significantly decreased velocity (60–69%) in all streams. Depth (18–61%) and wetted width (24–31%) tended to decrease but these changes were not always significant. Sediment cover increased the most in farmland streams (10–80%). Apart from decreasing temperature range (18–26%), flow reduction had little impact on the surface water temperatures.
5. Flow reduction had no impact on the abundance of common pool macroinvertebrates or on the abundance, vertical distribution or community composition of hyporheic macroinvertebrates.
6. Our results suggest that aquatic macroinvertebrates are resistant to short-term, severe flow reduction as long as some water remains.     

Predicting the locations of naturally fishless lakes

1. Fish have been introduced into many previously fishless lakes throughout North America over the past 100+ years. It is difficult to determine the historical distribution of fishless lakes, however, because these introductions have not always been well‐documented. 2. Due to its glacial history and low human population density, the state of Maine (U.S.A.) may host the greatest number of naturally fishless lakes in the northeastern United States. However, less than one‐quarter of Maine’s 6000+ lakes have been surveyed for fish presence, and no accurate assessments of either the historical or current abundance and distribution of fishless lakes exist. 3. We developed methods to assess the abundance and distribution of Maine’s naturally fishless lakes (0.6–10.1 ha). We hypothesized that the historical distribution of fishless lakes across a landscape is controlled by geomorphic and geographic conditions. 4. We used ArcGIS to identify landscape‐scale geomorphic and geographic factors (e.g. connectivity, surrounding slope) correlated with fish absence in two geomorphic regions of Maine – the western and interior mountains and the eastern lowlands and foothills. By using readily available geographic information systems data our method was not limited to field‐visited sites. We estimated the likelihood that a particular lake is fishless with a stepwise logistic regression model developed for each region. 5. The absence of fish from western lakes is related to altitude (+), minimum percent slope in the 500 m buffer (+), maximum percent slope in the 500 m buffer (+) and percent cover of herbaceous‐emergent wetland in 1000 m buffer (?). The absence of fish from eastern lakes is related to the lack of a stream within 50 m of the lake. 6. The models predict that a total of 4% (131) of study lakes in the two regions were historically fishless, with the eastern region hosting a greater proportion than the western region. 7. We verified the model predictions with two complementary approaches. First we visited 21 lakes predicted to be fishless and assessed current fish presence with gillnetting. Second, we used paleolimnological techniques based on the abundance of Chaoborus americanus mandibles in the bottom segments of sediment cores. Fifteen of the 21 lakes predicted to be fishless currently contain fish. Paleolimnological evidence, however, suggests that nine of the 15 lakes were historically fishless and thus were subject to undocumented fish introductions. 8. Our approach efficiently predicts the distribution Maine’s naturally fishless lakes, and our results indicate that these habitats have declined due to fish introductions. Our method could be applied to other regions with similar geographic and geomorphic constraints on fish distributions as a tool to enhance conservation of a limited resource that provides habitat for unique biological communities.     

Two new species of Bathypalaemonella Balss (Crustacea, Decapoda, Campylonotidae) from the Australian Northwest Shelf

Two new species of shrimp belonging to the campylonotid genus Bathypalaemonella Balss from the Australian Northwest Shelf. R. brevirostris sp.n. and B. pilosipes sp.n., are described and illustrated. constituting the first records of this genus from Australian waters. Present knowledge of the genus is reviewed and the distribution of the known species listed. The two new species can be readily distinguished from the previously described species of Banthypalaemonella by the very characteristic morphologies of the dactyls of their ambulatory pereiopods.     

Colonial Capitalism in Java

Control of Land and Labour in Colonial Java. By Jan Breman Javanese Peasants and the Colonial Sugar Industry. By R.E. Elson     

On the synchronization of breathing with running in wallabies (Macropus spp.) and horses (Equus caballus)

Previous investigations have shown that, when they run, wallabies and various quadrupedal mammals take exactly one breath per stride. It has been suggested that their breathing movements may be driven by the movements of running, and three mechanisms have been proposed: the lungs may be compressed and expanded by vibrations of a 'visceral piston', by bending and extension of the back or by the forces imposed on the rib cage by the forelegs.
The three mechanisms are tested against published observations on wallabies and horses. Simple mathematical models are used to predict the phase relationship between running and breathing for each mechanism, and the amplitudes of breathing that they could cause. The observed breathing movements of hopping wallabies are consistent with a visceral piston mechanism tuned to the stride frequency, but cannot be explained by either of the other mechanisms. Those of cantering and galloping horses are not consistent with a tuned visceral piston mechanism, but could be driven by the bending and extension of the back.     

WHICH BENEFITS OF RESEARCH PARTICIPATION COUNT AS ‘DIRECT’?

It is widely held that individuals who are unable to provide informed consent should be enrolled in clinical research only when the risks are low, or the research offers them the prospect of direct benefit. There is now a rich literature on when the risks of clinical research are low enough to enroll individuals who cannot consent. Much less attention has focused on which benefits of research participation count as ‘direct’, and the few existing accounts disagree over how this crucial concept should be defined. This disagreement raises concern over whether those who cannot consent, including children and adults with severe dementia, are being adequately protected. The present paper attempts to address this concern by considering first what additional protections are needed for these vulnerable individuals. This analysis suggests that the extant definitions of direct benefits either provide insufficient protection for research subjects or pose excessive obstacles to appropriate research. This analysis also points to a modified definition of direct benefits with the potential to avoid these two extremes, protecting individuals who cannot consent without blocking appropriate research.