Pancreatic and sacral agenesis in association with maternal diabetes mellitus: Case report

Sacral agenesis was diagnosed sonographically in the fetus of a diabetic mother and pancreatic agenesis was found additionally at autopsy.     

FOREST HYDROLOGY ISSUES FOR THE 21ST CENTURY: A CONSULTANT'S VIEWPOINT1

ABSTRACT: Forest hydrology should be a mature science with routine use of hydrological procedures to evaluate the effect of past, current and proposed harvesting practices on water resources. It is not. However, water users are pressuring forest managers to exercise their role in managing forested watersheds for water supply. Most forest managers are poorly equipped to carry out this role. Forestry schools need to ensure that their graduates, whether employed in forest management positions or as specialists in watershed management, understand that all forestry operations may affect instream or downstream water users. Specialists in forest hydrology should be fully aware of the following: (1) climate and watershed characteristics influence streamflow in separate ways; (2) forestry practices produce changes in water yield and quality, and that only these changes need to be evaluated to estimate their effects; (3) watershed storage is a critical factor in evaluating the effects of harvesting on streamflow; and (4) the effect of harvest on one watershed cannot be extrapolated to another without consideration of the processes affected. Research is needed to assist watershed managers in applying models to watersheds for which climate and streamflow data are insufficient. Research is also needed to incorporate climate, streamflow and other data for hydrological models into geographic information systems. Joint research projects are needed to develop physical relationships between stream channel characteristics of importance to fisheries biologists and streamflow characteristics affected by forest harvest.     

Endogenous swimming rhythms of blue crab, Callinectes sapidus , megalopae: effects of offshore and estuarine cues

Larvae of the blue crab Callinectes sapidus Rathbun develop on the continental shelf. The postlarval stage (megalopa) occurs near the surface and is transported shoreward by wind-driven surface currents. It then uses selective tidal stream transport for migration up an estuary. Endogenous swimming rhythms were measured under constant dark conditions in the laboratory in megalopae collected from the Newport River Estuary (North Carolina), the Delaware Bay, and offshore from the Newport River Estuary. Megalopae from all areas had a similar circadian activity rhythm, in which they swam during the time of the day phase in the field and were inactive at night. This rhythm predicts the presence of a reverse, diel, vertical-migration pattern offshore which would contribute to the location of megalopae near the surface during the day. The rhythm lacks obvious ecological significance in estuaries because it does not contribute to selective tidal stream transport and would increase vulnerability to visual predators during the day. Attempts to entrain a circatidal rhythm in swimming by cyclic and step changes in salinity were unsuccessful, as the circadian rhythm persisted. The rhythm also continued in the presence of the eelgrass Zostera marina, which is a site of settlement and metamorphosis in the field. Thus, megalopae enter estuaries with a solar day rhythm in activity. This rhythm, however, is not expressed, because light inhibits swimming during the day upon exposure to estuarine water. Since this light inhibition is removed in offshore waters, the rhythm would be expressed if, after entering an estuary, megalopae were transported back to offshore areas. Received: 19 December 1995 / Accepted: 2 August 1996     

Connectivity of Streams and Wetlands to Downstream Waters: An Integrated Systems Framework

Interest in connectivity has increased in the aquatic sciences, partly because of its relevance to the Clean Water Act. This paper has two objectives: (1) provide a framework to understand hydrological, chemical, and biological connectivity, focusing on how headwater streams and wetlands connect to and contribute to rivers; and (2) briefly review methods to quantify hydrological and chemical connectivity. Streams and wetlands affect river structure and function by altering material and biological fluxes to the river; this depends on two factors: (1) functions within streams and wetlands that affect material fluxes; and (2) connectivity (or isolation) from streams and wetlands to rivers that allows (or prevents) material transport between systems. Connectivity can be described in terms of frequency, magnitude, duration, timing, and rate of change. It results from physical characteristics of a system, e.g., climate, soils, geology, topography, and the spatial distribution of aquatic components. Biological connectivity is also affected by traits and behavior of the biota. Connectivity can be altered by human impacts, often in complex ways. Because of variability in these factors, connectivity is not constant but varies over time and space. Connectivity can be quantified with field‐based methods, modeling, and remote sensing. Further studies using these methods are needed to classify and quantify connectivity of aquatic ecosystems and to understand how impacts affect connectivity.     

Scaling up site disputes: strategies to redefine ‘local’ in the fight against fracking

Plans to replace an aging diesel backup energy plant with liquid natural gas (LNG) generators in Whitehorse, Yukon, resulted in a public outcry, involving community meetings, massive petitions, and demonstrations. Are these civil society protests just a case of a local siting dispute – a response to an unwanted industrial site in an urban neighborhood? Here, it is argued that siting debates are not the driver of these campaigns, but instead are harnessed by activists to advance a broader environmental movement. By linking the LNG project to more distant extraction, involving hydraulic fracturing (‘fracking’), movement leaders portray the entire territory as part of the ‘local’ for Whitehorse residents. Movement leaders rely upon two key mechanisms: claiming insider status, and identifying visible symbols. This case reveals the strategic use by environmental movements of local concerns to recruit support for broader campaigns, and the value of local, place-based activism for broader environmental movements.     

Regulation of spirocyst discharge in the model sea anemone, Nematostella vectensis

Test probes were touched to tentacles to investigate whether discharge of spirocysts likely is regulated by hair bundle mechanoreceptors. Significantly more spirocysts discharge onto test probes in the presence of vibrations at 11–15 Hz as compared to 0 Hz. Adding N-acetylneuraminic acid, NANA, shifts maximal discharge of spirocysts upwards to 36–40 Hz, and possibly to 21–25 Hz. In contrast, NANA shifts maximal discharge of basitrichous isorhiza nematocysts downwards to 1–20 Hz. Thus, discharge of cnidae (‘stinging capsules’) is differentially regulated according to the type of cnida. Furthermore, it appears that chemodetection of N-acetylated sugars is not a prerequisite to capturing prey because, in seawater alone, maximal discharge of cnidae occurs at frequencies overlapping movements of calmly swimming prey. Nevertheless, chemodetection of N-acetylated sugars broadens the range of frequencies stimulating maximal discharge of cnidae and, therefore, likely enhances prey capture.     

Abundances and variability of tropospheric volatile organic compounds at the South Pole and other Antarctic locations

Multiyear (2000–2006) seasonal measurements of carbon monoxide, hydrocarbons, halogenated species, dimethyl sulfide, carbonyl sulfide and C₁–C₄ alkyl nitrates at the South Pole are presented for the first time. At the South Pole, short-lived species (such as the alkenes) typically were not observed above their limits of detection because of long transit times from source regions. Peak mixing ratios of the longer lived species with anthropogenic sources were measured in late winter (August and September) with decreasing mixing ratios throughout the spring. In comparison, compounds with a strong oceanic source, such as bromoform and methyl iodide, had peak mixing ratios earlier in the winter (June and July) because of decreased oceanic production during the winter months. Dimethyl sulfide (DMS), which is also oceanically emitted but has a short lifetime, was rarely measured above 5 pptv. This is in contrast to high DMS mixing ratios at coastal locations and shows the importance of photochemical removal during transport to the pole. Alkyl nitrate mixing ratios peaked during April and then decreased throughout the winter. The dominant source of the alkyl nitrates in the region is believed to be oceanic emissions rather than photochemical production due to low alkane levels.Sampling of other tropospheric environments via a Twin Otter aircraft included the west coast of the Ross Sea and large stretches of the Antarctic Plateau. In the coastal atmosphere, a vertical gradient was found with the highest mixing ratios of marine emitted compounds at low altitudes. Conversely, for anthropogenically produced species the highest mixing ratios were measured at the highest altitudes, suggesting long-range transport to the continent. Flights flown through the plume of Mount Erebus, an active volcano, revealed that both carbon monoxide and carbonyl sulfide are emitted with an OCS/CO molar ratio of 3.3 × 10^?3 consistent with direct observations by other investigators within the crater rim.     

Differing rates of extra-group paternity between two populations of the Australian magpie (Gymnorhina tibicen)

Extra-pair paternity (EPP) is a common feature of the mating systems of many birds. The rate of EPP may vary between species, races and populations. A comparison of extra-group paternity (EGP) rates was made between two races of a group-living passerine, the Australian magpie (Gymnorhina tibicen), to determine if similar mating systems were being employed. The two populations had similar social structure, but differed in group size and dispersal. It was predicted that dispersal differences would have a profound effect on the rate of EGP between the populations, as the population with the lower rate of dispersal and higher chance of breeding with a close relative would engage in EGPs more frequently. Eight microsatellite loci were used to determine parentage in the white-backed Australian magpie (G. t. tyrannica). The rate of EGP was found to be 44%. Dispersal rates were estimated from observational data. Over half of the juvenile magpie cohort from the previous breeding season left the territorial group. These results contrast sharply with the results found by other researchers in a population of western Australian magpies (G. t. dorsalis). In this population, 82% EGP is recorded and dispersal of juveniles is close to nil. The results indicate that dispersal rate is a potentially important predictor of rates of extra-group fertilisations between populations of this species, and suggest that females maximise their reproductive output by avoiding breeding with close kin.Communicated by M. Soler