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The question of why males invest more into competition than offspring care is an age-old problem in evolutionary biology. On the one hand, paternal care could increase the fraction of offspring surviving to maturity. On the other hand, competition could increase the likelihood of more paternities and thus the relative number of offspring produced. While drivers of these behaviours are often intertwined with a wide range of other constraints, here we present a simple dynamic model to investigate the benefits of these two alternative fitness-enhancing pathways. Using this framework, we evaluate the sensitivity of equilibrium dynamics to changes in payoffs for male allocation to mating versus parenting. Even with strong effects of care on offspring survivorship, small competitive benefits can outweigh benefits from care. We consider an application of the model that includes men's competition for hunting reputations where big game supplies a benefit to all and find a frequency-dependent parameter region within which, depending on initial population proportions, either strategy may outperform the other. Results demonstrate that allocation to competition gives males greater fitness than offspring care for a range of circumstances that are dependent on life-history parameters and, for the large-game hunting application, frequency dependent. The greater the collective benefit, the more individuals can be selected to supply it.

Metal-laden acid drainage from the reclaimed Landusky open-pit mine is thought to be the major source of environmental degradation to Swift Gulch, a small stream in the Little Rocky Mountains of north-central Montana. Ground water enters Swift Gulch through a series of Fe-stained springs located in a fault zone that extends to the southwest into the mine complex. The contamination threatens the nearby Fort Belknap Indian Reservation downstream. In this study, a detailed evaluation of the water chemistry of Swift Gulch during baseflow conditions was performed to assist in development of remedial plans. A continuous tracer injection test was performed in October 2007 using a combination of LiBr and Rhodamine WT dye. The tracer results were combined with field synoptic sampling of Swift Gulch to provide metal loading profiles for major and trace solutes, including Al, As, Fe(II), Fe(III), Mn, Ni, and Zn, along the entire 1,500 m length of the stream. Evidence from the tracer test indicates that nearly all of the metal contaminants in Swift Gulch enter the stream in a 500 m reach that is coincident with the fault zone. Iron enters the stream chiefly in its reduced Fe(II) state but is quickly oxidized to Fe(III) and then precipitated as ferric oxy-hydroxide. This reaction releases protons, and contributes to a drop in pH of Swift Gulch from values >6 to values

SummaryThe theory of selection of quantitative traits is widely used in evolutionary biology, agriculture and other related fields. The fundamental model known as the breeder’s equation is simple, robust over short time scales, and it is often possible to estimate plausible parameters. In this paper it is suggested that the results of this model provide useful yardsticks for the description of social traits and the evaluation of transmission models. The differences on a standard personality test between samples of Old Order Amish and Indiana rural young men from the same county and the decline of homicide in Medieval Europe are used as illustrative examples of the overall approach. It is shown that the decline of homicide is unremarkable under a threshold model while the differences between rural Amish and non-Amish young men are too large to be a plausible outcome of simple genetic selection in which assortative mating by affiliation is equivalent to truncation selection.

This study reports the first set of data on the concentration of mercury in muscle tissue of several varieties of fish from Lake Titicaca, including the pejerrey (Basilichthyes bonariensis), the carachi (Orestias), and 2 types of indigenous catfish (Trichomycterus). Approximately 27% of the pejerrey and 75% of the carachi exceeded the US EPA fish tissue-based water quality criterion level of 0.30 microg g(-1). Mercury levels of pejerrey increased with fish size, although this relationship was less apparent for the smaller carachi. The pejerrey and carachi are important food fish for local residents. A synoptic sampling of the Río Ramis--the largest tributary to Lake Titicaca--was conducted in an attempt to determine if mercury releases from artisanal gold mining could be an important source of Hg contamination to Lake Titicaca. Although highly elevated concentrations of Hg and other heavy metals were documented in headwater streams near the mining centers of La Rinconada and Cecilia, the quantity of Hg entering Lake Titicaca that could be attributed to mining in the Ramis watershed was below the quantifiable limit in our July 2002 study. This does not diminish the localized threat to mercury exposure for the artisanal gold miners themselves, as well as their families. Further studies of mercury dynamics in Lake Titicaca are recommended, as well as in the rivers draining into the lake. It is probable that most of the downgradient transport of Hg and other trace metals from the headwater mining centers occurs as suspended sediment during seasonal periods of high-flow.

Interpretation of single-well tests with the Cooper-Jacob method remains more reasonable than most alternatives. Drawdowns from 628 simulated single-well tests where transmissivity was specified were interpreted with the Cooper-Jacob straight-line method to estimate transmissivity. Error and bias as a function of vertical anisotropy, partial penetration, specific yield, and interpretive technique were investigated for transmissivities that ranged from 10 to 10,000 m(2)/d. Cooper-Jacob transmissivity estimates in confined aquifers were affected minimally by partial penetration, vertical anisotropy, or analyst. Cooper-Jacob transmissivity estimates of simulated unconfined aquifers averaged twice the known values. Transmissivity estimates of unconfined aquifers were not improved by interpreting results with an unconfined aquifer solution. Judicious interpretation of late-time data consistently improved estimates where transmissivity exceeded 250 m(2)/d in unconfined aquifers.

Slug tests performed in high transmissivity aquifers may exhibit underdamped inertial oscillatory behavior. Analytical methods for oscillatory data have been developed, but are mathematically intimidating. Spreadsheet modeling is helpful because ready adjustments to the equations required to match the well-response data are quickly applied. A simplified presentation of the Kipp method for the practicing hydrogeologist is presented along with a spreadsheet model. A file containing the type curves is available over the Internet at http://www.mtech.edu from the Geological Engineering home page. Examples from southwestern Montana showing a variety of damping responses and well completions are presented to show how to perform the analysis. Sixteen well responses were modeled using the van der Kamp and Kipp methods, and the outcomes were compared using the two methods with oscillatory responses. Generally, there is good agreement between the methods. Screened wells tend to show more uniform oscillatory behavior, although open-hole completions can be analyzed with success. Other practical field applications and observations are presented. The theory describing inertial effects has been constrained to confined aquifers, although all aquifers exhibit elastic behavior during the initial disturbance from pumping or instantaneous slug removal.

Disinterested physical geology students can be enticed into performing an experiment that takes them though the scientific method and utilizes math skills if offered extra credit. The experiment causes students to compare the angle of repose of different substances, by measuring the heights and diameters of individual piles. The original experiment is given so that modification or use can be made by other geoscience instructors. During the last nine years I have evaluated over 700 height and diameter measurements from students of some 125 different substances to see how they are distributed statistically. Among the more interesting substances are earrings, stuffed animals, quarters, paper confetti, wadded garbage, corn chips, cassette tapes, and .22 caliber bullet shells. In spite of many sources of error and lack of experimental control, I found that the data are normally distributed.

We face an increasingly wide range of threats to our marine, coastal and estuarine environments, many aggravated by human activity. Attempts to manage these problems in isolation are looking ever more ineffective and unaffordable, and over-prescriptive regulation threatens to render many options inaccessible. However case studies around the world suggest a radically different more holistic approach. Examining all activities within a coastal zone, the needs of those that are pursuing them and the possibilities for mutually beneficial collaboration can reveal “win-win” opportunities for environmental and economic regeneration that current regulatory authorities and processes might never identify. These can often be delivered at little or no cost to the taxpayer. In many cases the primary drivers for such projects are economic but, since coastal economies are often founded on maximising the returns from their environment, there can be great benefits in an integrated approach. It is becoming clear that protection of habitat and prevention of all negative impacts, however small, may not always be the best tools to nurture our environment and that governments are rarely the best placed to deliver the required solutions. This paper explores the approach of seeking constructive contributions from all those active within a coastal locality and its adjacent marine environment with the aim of achieving a net positive environmental impact, often at little or no cost to the taxpayer, applying conventional risk management practice to mitigate negative impacts.

The U.S. Army Materials Technology Laboratory (MTL) was requested by the Tank and Automotive Command (TACOM) and the Military Traffic Management Command (MTMC) to investigate the performance of the modified front lift provisions on the high mobility, multipurpose, wheeled vehicle (HMMWV). In order to evaluate the front lift provisions, a series of simulated air lift, ultimate pull, and fatigue tests were performed. Each type of test was performed for two different load magnitudes and angles. In addition to the mechanical tests performed, nondestructive testing procedures were utilized to inspect the provisions for imperfections and cracks before and after testing. A finite element analysis (FEA) was also conducted to analyze the hook and the provision bracket for each of the two load configurations.