Cardiac responses to abiotic factors in two tropical limpets, occurring at different levels of the shore

Laboratory experiments tested whether the cardiac activity of two species of limpets (Cellana spp.), co-occurring on the rocky shores of Hong Kong but having different zonal distributions, was differently affected by variations in physical environmental characteristics. Experiments reproduced exposure of limpets to dehydration, high water temperature and reduced salinity, all conditions that can occasionally be faced by animals during low tides. Cardiographic traces were obtained using a non-invasive method based on infrared light sensors glued onto the limpet shell in a position directly over the heart. The signals were filtered and amplified, viewed on portable oscilloscopes and automatically transferred to computer. When tested under acclimation temperatures, the lower shore C. toreuma had faster heart rates than the upper shore C. grata, both in air and when submerged in seawater. Regular alternation of heartbeating and acardia were observed in C. grata exposed to both dry and saturated air, whilst C. toreuma showed transient acardia only during exposure to dry air. Both species showed a similar increase in heart rate with increasing temperature (Q₁₀~1.8 in the range 25-34°C). When submerged in freshwater, C. grata regularly alternated acardia with beating at a rate slightly lower than in seawater, whilst C. toreuma showed strong bradycardia with reduction of beat amplitude, followed by steady acardia. Recovery of heartbeating after return to initial salinity was faster in C. grata, whilst C. toreuma, initially bradycardic, showed a consistent return to tachycardia. Overall, this study shows that the two congeneric species exhibit different cardiac responses to variations in environmental characteristics, which may be related to their differing vertical distribution.     

Successful contracting based on candor,realism, and common goals

This article is intended to provide an overview of the issues involved in remediation contracting, from general principles of contract law and negotiation, to specific contract provisions of interest to the remediation community, to the practical consequences of including or not including these provisions on disputes arising under the contract. This article does not treat every potential issue arising in contracts concerning remediation, but hopefully it discusses many of these issues and provides an overview that will be helpful to the reader.     

Genetic uniformity of widely separated populations of the coral reef starfishLinckia laevigata from the East Indian and West Pacific Oceans,revealed by allozyme electrophoresis

Gene flow among 18 widely separated populations of the starfishLinckia laevigata was investigated using allozyme electrophoresis at seven polymorphic enzyme loci. Little genetic differentiation was observed among East Indian-West Pacific populations separated by thousands of kilometres. Gene flow was estimated to be of the same order of magnitude as that found in the highly connected Great Barrier Reef region. The absence of genetic structure over such a broad geographic range is consistent with any of three conclusions: (1) there is extensive dispersal among widely separated populations across the range examined, (2) there has been a rapid expansion of the East Indian-West Pacific populations in the recent past, or (3) the loci surveyed are under the influence of balancing selection. The first two conclusions are not totally exclusive, since a recent expansion over several thousand generations would also require rapid dispersal at some stage, although present-day levels of dispersal need not be of the same order. With the available data, it is not possible to distinguish which of these mechanisms is the most likely. The most parsimonious conclusion is that extremely low levels of population differentiation are consistent with the existence of a large, homogeneous, panmictic population, with extensive dispersal occurring throughout the East Indian-West Pacific.     

Prenatal diagnosis of PORCN-related developmental syndrome in a fetus: A novel phenotype

We report a case of a female fetus born to an unrelated couple with a complex fetal phenotype of a pleural effusion, a cardiac malformation, and syndactyly of the toes. Prenatal exome sequencing identified a variant of uncertain significance in the PORCN gene that was upgraded to likely pathogenic following postnatal clinical examination. The phenotype described in cases with variants in the PORCN gene is often associated with findings that cannot be prospectively diagnosed by ultrasonography. This is the first report of a prenatal phenotype involving a fetal effusion associated with variants in the PORCN gene, with skeletal findings identified later in gestation on ultrasonography. The diagnosis was confirmed on neonatal examination.     

Communicating About Smoke from Wildland Fire: Challenges and Opportunities for Managers

Wildland fire and associated management efforts are dominant topics in natural resource fields. Smoke from fires can be a nuisance and pose serious health risks and aggravate pre-existing health conditions. When it results in reduced visibility near roadways, smoke can also pose hazardous driving conditions and reduce the scenic value of vistas. Communicating about smoke, whether in the preparation phases before a planned burn or during a wildfire event, can enable those at risk to make informed decisions to minimize their exposure to smoke or choose alternate activities that mitigate smoke completely. To date, very little research has been completed on the social aspects of smoke, such as communication or public perceptions. Here, we present findings from an exploratory study that examined challenges and opportunities related to communication (within agencies or to the public) for management of smoke from wildland fires. Interviews were conducted in California, Oregon, Montana, and South Carolina among a purposive sample of individuals, who are involved in fire or smoke management. Findings indicate that smoke poses several challenges to management agencies. Findings also provide insight into potential strategies to address such challenges by improving communication in both inter- and intra-agency situations as well as with members of the public. In particular, prioritizing fire and smoke-related communication within agencies, allocating agency resources specifically for training in communication and outreach endeavors, taking advantage of existing resources including informal social networks among the public, and building long-term relationships both between agencies and with the public were viewed as effective.     

Prospects for repellent in pest control: current developments and future challenges

The overall interest in environmentally safe pest control methods and the rise of insecticide resistance in pest populations have prompted medical and agricultural entomology research on insect repellents in recent years. However, conducting research on repellent is challenging for several reasons: (1) the different repellent phenomena are not well defined; (2) it is difficult to test for and quantify repellent; (3) the physiological mechanisms are poorly known; (4) the field efficacy appears to be highly variable. Here, we identified five different types of repellent: expellency, irritancy, deterrency, odor masking and visual masking, and described behavioral bioassays to differentiate between them. Although these categories are currently defined by their behavioral response to different stimuli, we suggest new definitions based on their mechanism of action. We put forward three main hypotheses on the physiological mechanism: (1) a dose effect that modifies the behavior, (2) a repellent mechanism with specific receptors, or (3) inhibition of the transduction of neural information.     

A very unusual ‘groin’, the MV River Princess,Goa, India and its impacts upon tourism

On June 6, 2000, the Merchant Vessel River Princess – dead weight 114,645 tonnes and 261 m in length, grounded on the beach off the Candolim-Sinquerim coast, Goa, India, spilling some 40 tonnes of oil. In the past 10 years it has settled some 10 m into the sea bed and taken in circa 40,000 tonnes of sand. Until the ‘60’s the Goan economy centered on agriculture and fishing with very low key recreation. Over the last three decades it has become heavily reliant upon recreation, with 13 % of GDP arising from this sector. Nine million cubic metres of littoral drift occurs off this beach per annum, with the longshore current broken by rips into a series of circulating cells. The vessel acts as a massive groin so much so that downdrift, erosion of approximately 5 to 10 m/annum (dependent on the monsoon strength) is occurring at the Taj hotel site. Satellite imagery has shown that some 0.13 km² beach loss has occurred since 2001. Downdrift, the beach is circa 20 m wide compared to updrift areas where it exceeds 100 m. Embryo tombola growth has now commenced between shore and ship. In addition to this, the dune system is now seriously out of equilibrium and sand bags, geotextiles etc. are currently in use to combat dune foot erosion. Questionnaires (n?=?111) showed that 37 % of beach users ranked erosion as the top coastal problem. Sixty seven percent of beach users rated scenery as the most important quality of a beach and due to the grounded ship, >60 % rated the scenery as below average, as well as viewing the ship as a source of danger for swimming purposes.