Genetic sex determination in <Emphasis Type="Italic">Astatotilapia calliptera</Emphasis>, a prototype species for the Lake Malawi cichlid radiation

East African cichlids display extensive variation in sex determination systems. The species Astatotilapia calliptera is one of the few cichlids that reside both in Lake Malawi and in surrounding waterways. A. calliptera is of interest in evolutionary studies as a putative immediate outgroup species for the Lake Malawi species flock and possibly as a prototype ancestor-like species for the radiation. Here, we use linkage mapping to test association of sex in A. calliptera with loci that have been previously associated with genetic sex determination in East African cichlid species. We identify a male heterogametic XY system segregating at linkage group (LG) 7 in an A. calliptera line that originated from Lake Malawi, at a locus previously shown to act as an XY sex determination system in multiple species of Lake Malawi cichlids. Significant association of genetic markers and sex produce a broad genetic interval of approximately 26 megabases (Mb) using the Nile tilapia genome to orient markers; however, we note that the marker with the strongest association with sex is near a gene that acts as a master sex determiner in other fish species. We demonstrate that alleles of the marker are perfectly associated with sex in Metriaclima mbenjii, a species from the rock-dwelling clade of Lake Malawi. While we do not rule out the possibility of other sex determination loci in A. calliptera, this study provides a foundation for fine mapping of the cichlid sex determination gene on LG7 and evolutionary context regarding the origin and persistence of the LG7 XY across diverse, rapidly evolving lineages.     

Metal stress and decreased tree growth in response to biosolids application in greenhouse seedlings and in situ Douglas-fir stands

To assess physiological impacts of biosolids on trees, metal contaminants and phytochelatins were measured in Douglas-fir stands amended with biosolids in 1982. A subsequent greenhouse study compared these same soils to soils amended with fresh wastewater treatment plant biosolids. Biosolids-amended field soils had significantly higher organic matter, lower pH, and elevated metals even after 25 years. In the field study, no beneficial growth effects were detected in biosolids-amended stands and in the greenhouse study both fresh and historic biosolids amendments resulted in lower seedling growth rates. Phytochelatins - bioindicators of intracellular metal stress - were elevated in foliage of biosolids-amended stands, and significantly higher in roots of seedlings grown with fresh biosolids. These results demonstrate that biosolids amendments have short- and long-term negative effects that may counteract the expected tree growth benefits.     

Public expectations about access fees and road closures on public lands

It is sometimes suggested that land managers could better communicate with the general public by relying on people who are active in community affairs to frame the message. By comparing responses from the ‘attentive’ and general public on the Colorado Plateau in the USA, this study investigated the expected effects of using recreation access fees or road closures to manage recreation on public lands. Although neither the attentive nor general public strongly anticipated benefits from the two management options, the attentive public was more likely than the general public to report positive expectations. Those more likely to expect fewer benefits from the management options do so because of factors that are outside the influence of managers (e.g., socio-demographics and value orientation). The results point out challenges for building public support through mobilizing the attentive public to develop a positive management atmosphere with fees and road closures.     

Risk-based Decision Process for Arsenic in Soils: Implications of Conservative Protocols

Making defensible risk-based decisions is a complex process that incorporates risk assessment into a risk management framework. Many site investigations require additional study, negotiations and/or actions for arsenic detected in soil samples, in many cases where no process related sources are identified and no other chemicals of concern are identified. Regulatory agencies develop guidance to standardize approaches to risk-based site investigations that focus on achieving "safe" concentrations. For arsenic, the action level is frequently in the "gray region", a U.S. Environmental Protection Agency (USEPA) term associated with a region of high uncertainty for risk management decisions in the "decision performance curve" associated with the data quality objective (DQO) process. Recognizing the conservative nature of the risk-based screening value for arsenic, approaches to enforce this level (or proof of comparability to natural background) may have numerous consequences including ineffective use of resources, stigmas on properties or actions at industrial or hazardous sites that are inconsistent with their regional setting. Florida has developed regulations and guidance on investigation of brownfield sites and has supported a study by the University of Florida (UF) to evaluate natural background concentrations in Florida soils. This paper discusses the sources of uncertainty near the soil cleanup target levels (SCTLs) in the Florida decision-making framework.     

GENERATING FARM DESCRIPTIONS IN A WATERSHED FROM INCOMPLETE DATA USING SIMULATED ANNEALING1

ABSTRACT: A fundamental problem faced in developing spatially explicit, simulation‐based analyses of watershed management and policy options is determining the distribution and spatial location of agricultural resources within a watershed based on incomplete information. This paper describes the use of simulated annealing, a heuristic scheduling process, to generate an assignment of all livestock and agricultural fields in a watershed to hypothetical farms such that the combined distribution of farm types, livestock, and farmland within the watershed is a reasonable representation of watershed‐level data. Compared to a manual method using GIS‐based analysis and data from aerial photography, the heuristic method was more likely to generate realistic spatial characterizations of the distribution of agricultural resources and practices in a watershed. Also compared to the manual method, the heuristic process was considerably more efficient and could more easily accommodate multiple criteria and modifications to those criteria.     

A Realistic Vehicle Emission Inspection System

A one minute mass vehicle exhaust emission inspection system is described to aid those seeking to establish an appropriate effort in compliance with the Air Quality Act of 1967. This proposed inspection system is suitable for both emission controlled and pre-emission controlled automobiles. It is oriented to appropriate Auto Service Industry corrective measures since it provides guidelines as to probable cause of unnecessarily high emissions for each rejected vehicle. This capability is essential to avoid abnormal corrective expense due to excessive repairs or continued high emissions due to inadequate repairs. Low skill levels may be used during the inspection process, yet results are repeatable and consistent in a plurality of inspection stations. The net gain in lower emissions through inspection of in-use vehicles is large because the point of rejection is no longer dictated by the inherently high emission vehicles. Not more than two rejection standards are required for emission controlled vehicles, and only one for pre-emission controlled vehicles. This includes all domestic and foreign makes. These standards are flexible in that they may be initially liberal and gradually tightened as circumstances warrant. Such policy changes or future spark ignition engine designs will not significantly obsolete the hardware required to perform this inspection. The fundamental techniques employed permit the use of greatly simplified equipment and instrumentation with resultant lower initial cost and increased reliability than previously envisioned meaningful inspection methods. A study of nearly 1000 automobiles over a one year period evolved and documented this proposed inspection system. Qualified persons may study this work to any depth desired by contacting the authors.