The North American Waterfowl Management Plan highlights the importance of enhancing waterfowl habitat for productivity and resilience. Many forms of land management are conducted in wetlands to support the diverse communities of waterfowl and other species. Primary burrowing crayfish are also abundant and important in these environments, but little research is available assessing the effects of waterfowl land management on primary burrowers. We examined the response of the digger crayfish, Creaserinus fodiens, to the common vegetation management practices of mowing and disking at waterfowl conservation areas in south-eastern Missouri. Our results demonstrated that at a fine scale, crayfish density was affected by only canopy cover. We also highlighted distributional effects of landscape-level environmental variables and suggested that habitat generalists were tolerant of vegetation management, responding more to vegetation composition and broader landscape effects. We discuss wetlands conservation practices and suggest that burrowing crayfish management would integrate well with some current management strategies for waterfowl.

Electroencephalographic (EEG) abnormalities are greater in mild cognitive impairment (MCI) with Lewy bodies (MCI-LB) than in MCI due to Alzheimer’s disease (MCI-AD) and may anticipate the onset of dementia. We aimed to assess whether quantitative EEG (qEEG) slowing would predict a higher annual hazard of dementia in MCI across these etiologies. MCI patients (n = 92) and healthy comparators (n = 31) provided qEEG recording and underwent longitudinal clinical and cognitive follow-up. Associations between qEEG slowing, measured by increased theta/alpha ratio, and clinical progression from MCI to dementia were estimated with a multistate transition model to account for death as a competing risk, while controlling for age, cognitive function, and etiology classified by an expert consensus panel.

Over a mean follow-up of 1.5 years (SD = 0.5), 14 cases of incident dementia and 5 deaths were observed. Increased theta/alpha ratio on qEEG was associated with increased annual hazard of dementia (hazard ratio = 1.84, 95% CI: 1.01–3.35). This extends previous findings that MCI-LB features early functional changes, showing that qEEG slowing may anticipate the onset of dementia in prospectively identified MCI.

The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

The Holocene portion of the Siple Dome (Antarctica) ice core was dated by interpreting the electrical, visual and chemical properties of the core. The data were interpreted manually and with a computer algorithm. The algorithm interpretation was adjusted to be consistent with atmospheric methane stratigraphic ties to the GISP2 (Greenland Ice Sheet Project 2) ice core, 10Be stratigraphic ties to the dendrochronology 14 C record and the dated volcanic stratigraphy. The algorithm interpretation is more consistent and better quantified than the tedious and subjective manual interpretation.

We measured vertical strain in the firn at Siple Dome, Antarctica, using two systems, both of which measure relative displacements over time of metal markers placed in an air-filled borehole. One system uses a metal-detecting tuned coil, and the other uses a video camera to locate the markers. We compare the merits of the two systems. We combine steady-state calculations and a measured density profile to estimate the true vertical-velocity profile. This allows us to calculate a depth-age scale for the firn at Siple Dome. Our steady-state depth-age scale has ages ≈10-15% younger at any given depth when compared to depth-age scales derived by layer counting in a core 40 m away. The age of a visible ash layer at 97 m in the core is 665 ± 30 years, in agreement with a similar analysis conducted at Taylor Dome, Antarctica, where the same ash is also seen, providing an additional dated tie point between the two cores.

Surgical experiments were conducted on cultured five-node apical rhizome segments of quackgrass. Removal of scale leaves promoted an initial burst of growth within the axillary buds but did not support the continued growth of buds as effectively as removal of the rhizome apex. Replacement of detached scale leaves over denuded buds temporarily repressed the promotive effect of scale leaf removal. Aqueous extracts of scale leaf material inhibited apical growth in rhizome segments but did not inhibit bud growth. Anatomical sections revealed that removal of scale leaves promoted development of buds: cells enlarged, vascular tissues differentiated, and new nodes began to form within 4 days of the removal of scale leaves. It is suggested that scale leaves contribute to apical dominance by inhibiting the initial development of axillary buds.

A growing segment of society is concerned about a myriad of health and environmental issues related to the use of pesticides and other agricultural chemicals. Despite the leveling-off of agricultural chemical use in the 1980s, chemical use in agriculture has come to be seen as a two-edged sword. On the positive side, agricultural chemicals have become the engine for world-wide productivity gains. These chemicals have contributed to increased yields per acre and have reduced waste in storage and distribution. On the negative side, agricultural chemicals are perceived by many to present risks to the safety of the food we eat, to the quality of our drinking water, to the wildlife population, to applicators and to people who inadvertently come into point contact with them.

Four soil chronosequences in the southern Great Basin were examined in order to study and quantify soil development during the Quaternary. Soils of all four areas are developed in gravelly alluvial fans in semiarid climates with 8 to 40 cm mean annual precipitation. Lithologies of alluvium are granite-gneiss at Silver Lake, granite and basalt at Cima Volcanic Field, limestone at Kyle Canyon, and siliceous volcanic rocks at Fortymile Wash. Ages of the soils are approximated from several radiometric and experimental techniques, and rates are assessed using a conservative mathematical approach. Average rates for Holocene soils at Silver Lake are about 10 times higher than for Pleistocene soils at Kyle Canyon and Fortymile Wash, based on limited age control. Holocene soils in all four areas appear to develop at similar rates, and Pleistocene soils at Kyle Canyon and Fortymile Wash may differ by only a factor of 2 to 4. Over time spans of several millennia, a preferred model for the age curves is not linear but may be exponential or parabolic, in which rates decrease with increasing age. These preliminary results imply that the geographical variation in rates within the southern Great Basin-Mojave region may be much less significant than temporal variation in rates of soil development. The reasons for temporal variation in rates and processes of soil development are complexly linked to climatic change and related changes in water and dust, erosional history, and internally driven chemical and physical processes.

Dynamic programming techniques were used to evaluate the effects of alternative levels of normal flex acreage requirements on a Midwestern corn-soybean farm and a Southeastern cotton farm. Results indicate that increasing normal flex acres from the current level of 15 percent to 35 percent would provide inducement for farmers in both regions to plant more soybeans. In general, the cotton farm incurs considerably higher expected losses from the change. Thus, there are unequal regional consequences of such a policy change.

Understanding the distribution of gas in and around galaxies is vital for our interpretation of galaxy formation and evolution. As part of the Arecibo Galaxy Environment Survey (AGES) we have observed the neutral hydrogen (HI) gas in and around the nearby Local Group galaxy M33 to a greater depth than previous observations. As part of this project we investigated the absence of optically detected dwarf galaxies in its neighbourhood, which is contrary to predictions of galaxy formation models. We observed 22 discrete clouds, 11 of which were previously undetected and none of which have optically detected counterparts. We find one particularly interesting hydrogen cloud, which has many similar characteristics to hydrogen distributed in the disk of a galaxy. This cloud, if it is at the distance of M33, has a HI mass of around 107 M⊙ and a diameter of 18 kpc, making it larger in size than M33 itself.

Recent studies suggest that sand can serve as a vehicle for exposure of humans to pathogens at beach sites, resulting in increased health risks. Sampling for microorganisms in sand should therefore be considered for inclusion in regulatory programmes aimed at protecting recreational beach users from infectious disease. Here, we review the literature on pathogen levels in beach sand, and their potential for affecting human health. In an effort to provide specific recommendations for sand sampling programmes, we outline published guidelines for beach monitoring programmes, which are currently focused exclusively on measuring microbial levels in water. We also provide background on spatial distribution and temporal characteristics of microbes in sand, as these factors influence sampling programmes. First steps toward establishing a sand sampling programme include identifying appropriate beach sites and use of initial sanitary assessments to refine site selection. A tiered approach is recommended for monitoring. This approach would include the analysis of samples from many sites for faecal indicator organisms and other conventional analytes, while testing for specific pathogens and unconventional indicators is reserved for high-risk sites. Given the diversity of microbes found in sand, studies are urgently needed to identify the most significant aetiological agent of disease and to relate microbial measurements in sand to human health risk.

A long-season (160–180 days) cotton variety with a conventional production system was formerly grown in the Texas Coastal Bend Region. Cotton producers in the region used intensive insecticide applications throughout the growing season and harvested in August or September, and occasionally in October. In general, intensive insecticide applications for boll weevil and fleahopper control destroyed the beneficial insects and spiders. Late-season tobacco budworm infestations were thereby aggravated. These late-season insect infestations were a result of the relatively high rainfall during August and September. Moreover, high rainfall during this time not only interfered with harvest, but also reduced both the yield and quality of cotton (Lacewell et al.).

Throughout the southern states and at the federal level, much attention is being focused on the appropriate strategy for controlling cotton insect pests, particularly the boll weevil. This paper presents estimated economic impacts to farmers, regions and consumers of implementing three alternative boll weevil control strategies. One strategy evaluated is a proposed boll weevil eradication program which involves integrating many controls including insecticides, reproduction-diapause control by early season stalk destruction, pheromone-baited traps, trap crops, early season control with insecticide, and massive releases of sterile boll weevils. The plan is to eradicate the boll weevil in the U.S., and then indefinitely maintain a barrier at the U.S.-Mexico border to prevent future weevil immigration to the U.S.