Plasma Physics

Contains research objectives and reports on three research projects.United States Atomic Energy Commission AT(30-1)-1842

The Spectral Energy Distribution of Dust Emission in the Edge-on spiral galaxy NGC 4631 as seen with Spitzer and the James Clerk Maxwell telescope

We explore variations in dust emission within the edge-on Sd spiral galaxy NGC 4631 using 3.6-160 μm Spitzer Space Telescope data and 450-850 μm JCMT data with the goals of understanding the relation between PAHs and dust emission, studying the variations in the colors of the dust emission, and searching for possible excess submillimeter emission compared to what is expected from dust models extrapolated from far-infrared wavelengths. The 8 μm PAH emission correlates best with 24 μm hot dust emission on 1.7 kpc scales, but the relation breaks down on 650 pc scales, possibly because of differences in the mean free paths between photons that excite the PAHs and photons that heat the dust and possibly because the PAHs are destroyed by the hard radiation fields within some star formation regions. The ratio of 8 μm PAH emission to 160 μm cool dust emission appears to vary as a function of radius. The 70 μm/160 μm and 160 μm/450 μm flux density ratios are remarkably constant even though the surface brightnesses vary by factors of 25, which suggests that the emission is from dust heated by a nearly uniform radiation field. Globally, we find an excess of 850-1230 μm emission relative to what would be predicted by dust models. The 850 μm excess is highest in regions with low 160 μm surface brightnesses, although the magnitude depends on the model fit to the data. We rule out variable emissivity functions or ~4 K dust as the possible origins of this 850 μm emission, but we do discuss the other possible mechanisms that could produce the emission

Plasma Physics

Contains reports on five research projects.United States Atomic Energy Commission (Contract AT(30-1)-1842

Statistical Communication Theory

Contains reports on six research projects

Risk Factors for Diarrhea in Children Under Five Years of Age Residing in Peri-Urban Communities in Cochabamba, Bolivia

This study examined the relationship between childhood diarrhea prevalence and caregiver knowledge of the causes and prevention of diarrhea in a prospective cohort of 952 children \u3c 5 years of age in Cochabamba, Bolivia. The survey of caregiver knowledge found that more than 80% of caregivers were unaware that hand washing with soap could prevent childhood diarrhea. Furthermore, when asked how to keep food safe for children to eat only 17% of caregivers reported hand washing before cooking and feeding a child. Lack of caregiver awareness of the importance of practices related to hygiene and sanitation for diarrhea prevention were significant risk factors for diarrheal disease in this cohort. The knowledge findings from this study suggest that health promotion in these communities should put further emphasis on increasing knowledge of how water treatment, hand washing with soap, proper disposal of child feces, and food preparation relate to childhood diarrhea prevention

Representative Farms Economic Outlook for the December 2005 FAPRI/AFPC Baseline

The Agricultural and Food Policy Center (AFPC) at Texas A&M University develops and maintains data to simulate 102 representative crop and livestock operations in major production areas in 28 states. The chief purpose of this analysis is to project those farms’ economic viability for 2005 through 2011. The data necessary to simulate the economic activity of these operations is developed through ongoing cooperation with panels of agricultural producers in each of these states. The Food and Agricultural Policy Research Institute (FAPRI) provided projected prices, policy variables, and input inflation rates in their December 2005 Baseline. Under the December 2005 Baseline, 12 of the 66 crop farms are considered in good liquidity condition (less than a 25 percent chance of negative ending cash during 2005-2011). Five crop farms have between a 25 percent and a 50 percent likelihood of negative ending cash. The remaining 49 crop farms have greater than a 50 percent of negative ending cash. Additionally, 22 of the 66 crop farms are considered in good equity position (less than a 25 percent chance of decreasing real net worth during 2005-2011). Ten crop farms have between a 25 percent and 50 percent likelihood of losing real net worth, and 34 crop farms have greater than a 50 percent probability of decreasing real net worth.Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Livestock Production/Industries,

Ultraviolet through far-infrared spatially resolved analysis of the recent star formation in M81 (NGC 3031)

The recent star formation (SF) in the early-type spiral galaxy M81 is characterized using imaging observations from the far-ultraviolet to the far-infrared. We compare these data with models of the stellar, gas, and dust emission for subgalactic regions. Our results suggest the existence of a diffuse dust emission not directly linked to the recent star formation. We find a radial decrease of the dust temperature and dust mass density, and in the attenuation of the stellar light. The IR emission in M81 can be modeled with three components: (1) cold dust with a temperature = 18 ± 2 K, concentrated near the H II regions but also presenting a diffuse distribution; (2) warm dust with = 53 ± 7 K, directly linked with the H II regions; and (3) aromatic molecules, with diffuse morphology peaking around the H II regions. We derive several relationships to obtain total IR luminosities from IR monochromatic fluxes, and we compare five different star formation rate (SFR) estimators for H II regions in M81 and M51: the UV, H alpha, and three estimators based on Spitzer data. We find that the H alpha luminosity absorbed by dust correlates tightly with the 24 mu m emission. The correlation with the total IR luminosity is not as good. Important variations from galaxy to galaxy are found when estimating the total SFR with the 24 mu m or the total IR emission alone. The most reliable estimations of the total SFRs are obtained by combining the H alpha emission (or the UV) and an IR luminosity (especially the 24 mu m emission), which probe the unobscured and obscured SF, respectively. For the entire M81 galaxy, about 50% of the total SF is obscured by dust. The percentage of obscured SF ranges from 60% in the inner regions of the galaxy to 30% in the outer zones

Representative Farms Economic Outlook for the January 2005 FAPRI/AFPC Baseline

The farm level economic impacts of the Farm Security and Rural Investment Act of 2002 on representative crop and livestock operations are projected in this report. The analysis was conducted over the 2002-2009 planning horizon using FLIPSIM, AFPC’s whole farm simulation model. Data to simulate farming operations in the nation’s major production regions came from two sources:•Producer panel cooperation to develop economic information to describe and simulate representative crop, livestock, and dairy farms, and•Projected prices, policy variables, and input inflation rates from the Food and Agricultural Policy Research Institute (FAPRI) January 2005 Baseline. The FLIPSIM policy simulation model incorporates the historical risk faced by farmers for prices and production. This report presents the results of the January 2005 Baseline in a risk context using selected simulated probabilities and ranges for annual net cash farm income values. The probability of a farm experiencing negative ending cash reserves and the probability of a farm losing real net worth are included as indicators of the cash flow and equity risks facing farms through the year 2009.Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Livestock Production/Industries,

Representative Farms Economic Outlook for the August 2005 FAPRI/AFPC Baseline

The farm level economic impacts of the Farm Security and Rural Investment Act of 2002 on representative crop and livestock operations are projected in this report. The analysis was conducted over the 2002-2009 planning horizon using FLIPSIM, AFPC’s whole farm simulation model. Data to simulate farming operations in the nation’s major production regions came from two sources: • Producer panel cooperation to develop economic information to describe and simulate representative crop, livestock, and dairy farms, and • Projected prices, policy variables, and input inflation rates from the Food and Agricultural Policy Research Institute (FAPRI) August 2005 Baseline. The FLIPSIM policy simulation model incorporates the historical risk faced by farmers for prices and production. This report presents the results of the August 2005 Baseline in a risk context using selected simulated probabilities and ranges for annual net cash farm income values. The probability of a farm experiencing negative ending cash reserves and the probability of a farm losing real net worth are included as indicators of the cash flow and equity risks facing farms through the year 2009.Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Livestock Production/Industries,

The Deglaciation of Maine, USA

The glacial geology of Maine records the northward recession of the Late Wisconsinan Laurentide Ice Sheet, followed by development of a residual ice cap in the Maine-Québec border region due to marine transgression of the St. Lawrence Lowland in Canada. The pattern of deglaciation across southern Maine has been reconstructed from numerous end moraines, deltas and submarine fans deposited during marine transgression of the coastal lowland. Inland from the marine limit, a less-detailed sequence of deglaciation is recorded by striation patterns, meltwater channels, scattered moraines and waterlain deposits that constrain the trend of the ice margin. There is no evidence that the northern Maine ice cap extended as far south-west as the Boundary Mountains and New Hampshire border. Newly-obtained radiocarbon ages from marine and terrestrial ice-proximal environments have improved the chronology of glacial recession in Maine. Many of these ages were obtained by coring late-glacial sediments beneath ponds and lakes. Data from this study show that the state was deglaciated between about 14.5 and 11.0 ka BP (14C years). The coastal moraine belt in southern Maine was deposited by oscillatory ice-margin retreat during the cold pre-Bølling time. Rapid ice recession to northern Maine then occurred between 13 and 11 ka BP, during the warmer Bølling/Allerød chronozones. Radiocarbon-dated pond sediments in western and northern Maine show lithologic evidence of Younger Dryas climatic cooling and persistence of the northern ice cap into Younger Dryas time. A large discrepancy still exists between radiocarbon ages of deglaciation in coastal south-western Maine and the timing of ice retreat indicated by New England varve records in areas to the west. Part of this problem may stem from the uncertainty of reservoir corrections applied to the radiocarbon ages of marine organics