Relative biological effectiveness of fast neutrons compared with X-rays: Prenatal mortality in the mouse

The effects of fission neutrons and of X-rays on the mouse zygote are discussed. Seven-week-old virgin mice were allowed a 12-hour mating opportunity beginning at 7:00 P.M. Between 1:30 and 4:00 P.M., except where indicated otherwise, the females which had mated (vaginal plug) during the night were either irradiated or sham-irradiated. At the time of irradiation the zygotes were in a pronuclear stage. Sixteen days later the mice were killed and the uteri dissected. The number of dead embryos, live embryos, and gross anomalies were determined. Dead embryos were classified as to stage of development

COHESION, INTEGRATION, AND ATTACHMENT IN OWYHEE COUNTY COMMUNITIES

How social change occurs is an important consideration when analyzing the effects of public land management policies on rural communities. This paper utilizes data from a recent study in Owyhee County, Idaho, to explore the combination of social attributes that contribute to community attitudes of cohesion, integration, and attachment in a set of rural communities. Specifically, we examine the importance of social networks and where a particular public land activity, ranching, fits into those networks. We then evaluate the role such networks play in determining respondent attitudes about the cohesiveness of their community, how they are integrated with people in their community, and how attached they are to where they live. The results indicate that increasing density of acquaintenship and intimate social connections to ranching and other local businesses increase the strength of cohesion and integration attitudes. Density of acquaintenship and intimate social connections to local businesses increase community attachment, but a social connection to ranching does not.Community/Rural/Urban Development, Land Economics/Use,

RANCH-LEVEL ECONOMIC IMPACTS OF GRAZING POLICY CHANGES: A CASE STUDY FROM OWYHEE COUNTY, IDAHO

Economic impacts often are cited as justification both for and against changes in grazing policy on public lands. A recent study conducted in Owyhee County, Idaho, illustrates a process to gather ranch-level economic information, develop economic models for different ranching systems, and use the models to estimate economic impacts of grazing policy changes. Ranch-level models were developed from producer panels and interviews within the county. Costs and returns, livestock production information, dependency on public lands, and other factors relative to ranch-level economics were gathered in four meetings with livestock producers and other interested parties. Results indicate that, as dependency on federal lands rise, both costs and returns fall. Ranch-level economic impacts of alternative grazing policy scenarios also are detailed.Land Economics/Use, Agricultural and Food Policy,

Status of sonic boom methodology and understanding

In January 1988, approximately 60 representatives of industry, academia, government, and the military gathered at NASA-Langley for a 2 day workshop on the state-of-the-art of sonic boom physics, methodology, and understanding. The purpose of the workshop was to assess the sonic boom area, to determine areas where additional sonic boom research is needed, and to establish some strategies and priorities in this sonic boom research. Attendees included many internationally recognized sonic boom experts who had been very active in the Supersonic Transport (SST) and Supersonic Cruise Aircraft Research Programs of the 60's and 70's. Summaries of the assessed state-of-the-art and the research needs in theory, minimization, atmospheric effects during propagation, and human response are given

COMPUTABLE GENERAL EQUILIBRIUM MODELING OF RANGELAND FIRES IN NORTHERN NEVADA

Resource /Energy Economics and Policy,

RANGELAND FIRES IN NORTHERN NEVADA: AN APPLICATION OF COMPUTABLE GENERAL EQUILIBRIUM MODELING

Resource /Energy Economics and Policy,

Divergence in social traits in Trinidadian guppies selectively bred for high and low leadership in a cooperative context

This is the final version. Available on open access from Nature Research via the DOI in this recordIn many animal species, individuals with certain morphological, physiological, or behavioural traits may have a disproportionately large role in determining group behaviour. While most empirical studies of leadership have focused on behaviour of individuals exploring new environments or foraging, little is known about leading behaviour in other ecological contexts. Here, we use a selective breeding design in the Trinidadian guppy (Poecilia reticulata) to quantify the heritability of leadership in a cooperative context, and determine the behavioural traits associated with it. Firstly we found that phenotypic selection for high and low leadership (HL and LL, respectively) over three filial generations resulted in pronounced differences in leadership tendency with a moderate degree of heritability. In our assay of other social traits, LL males were more aggressive and sampled their social environment less than HL males, but HL and LL females did not differ in either aggressiveness or sociability. Traits such as boldness and exploratory tendency did not diverge between the two lines. Leading behaviour was thus associated with social traits in males, but not females; suggesting that there may be sex-specific mechanisms driving the emergence of leadership in this context. We discuss our findings in the context of the evolution of cooperation.Danish Research Counci