Application of ERTS-1 Imagery to Flood Inundation Mapping

Application of ERTS-1 imagery to flood inundation mapping in East and West Nishnabotna basins of southwestern Iow

Wind-aligned Drainage in Loess in Iowa

Analysis of stream valley alignment reveals that first-order valleys, which are formed entirely within Wisconsinan loess, show a strongly preferred orientation of N40-50 degrees W, within an otherwise random distribution. This alignment is present in NW, W Central, and Central Iowa. It is not apparent in S Iowa. In NE and E Iowa wind-aligned features change to a N60-70 degree W orientation. This is interpreted as wind-alignment of the low-order valleys within the loess, created by prevailing NW winds during or shortly after loess deposition. Higher order streams are controlled by the till landscape beneath the loess. The four directions of preferred orientation in these higher order valleys are coincident with till joints

Water Quality Monitoring (1988 to 1991) At The Iowa Academy of Science\u27s Parish Farm, Grundy County, Iowa

In May 1988 sampling was initiated to evaluate water quality in relation to management practices at Parish Farm, which is owned by Iowa Academy of Science. Initial results showed tile-line effluent to have high concentrations of nitrate-nitrogen (N03-N). Twelve monitoring wells were installed over a one year period to analyze shallow groundwater at the farm. The wells, tile lines, and surface water were sampled monthly, through October, 1991, and the water analyzed for N03-N and some pesticides. N03-N concentrations varied, related to landuse and management of adjacent areas. Greater N03-N concentrations were detected from row-cropped areas than in the restored wildlife-vegetation buffer strip and prairie areas. The greatest concentrations (up to 79 mg/L) were associated with greater amounts of fertilized corn in the cropping sequence. Concentrations of pesticides were dependent on various factors such as chemical properties, season, hydrologic events, and patterns of use. Atrazine was the pesticide most often detected and was present in 46% of the samples. Seven agricultural pesticides used on the farm were detected in water samples with a maximum detected concentration of 6.9 μ/gL (for alachlor). Pesticide and high N03-N concentrations were detected in wells beneath the restored natural vegetation buffer areas, probably as a result of groundwater transport from application areas upgradient. The data suggest that the buffer strips were not effective at removing N03-N or pesticides from the groundwater flowing through these areas. N03-N concentrations were high (often over 25 μg/L) during the study, in spite of improved N management on the farm. The high concentrations may be related to mobilization of excess residual N03-N that accumulated during the dry years prior to the monitoring

Spin-orbit coupling and electron spin resonance for interacting electrons in carbon nanotubes

We review the theoretical description of spin-orbit scattering and electron spin resonance in carbon nanotubes. Particular emphasis is laid on the effects of electron-electron interactions. The spin-orbit coupling is derived, and the resulting ESR spectrum is analyzed both using the effective low-energy field theory and numerical studies of finite-size Hubbard chains and two-leg Hubbard ladders. For single-wall tubes, the field theoretical description predicts a double peak spectrum linked to the existence of spin-charge separation. The numerical analysis basically confirms this picture, but also predicts additional features in finite-size samples.Comment: 19 pages, 4 figures, invited review article for special issue in J. Phys. Cond. Mat., published versio

Estimation of Dietary Iron Bioavailability from Food Iron Intake and Iron Status

Currently there are no satisfactory methods for estimating dietary iron absorption (bioavailability) at a population level, but this is essential for deriving dietary reference values using the factorial approach. The aim of this work was to develop a novel approach for estimating dietary iron absorption using a population sample from a sub-section of the UK National Diet and Nutrition Survey (NDNS). Data were analyzed in 873 subjects from the 2000–2001 adult cohort of the NDNS, for whom both dietary intake data and hematological measures (hemoglobin and serum ferritin (SF) concentrations) were available. There were 495 men aged 19–64 y (mean age 42.7±12.1 y) and 378 pre-menopausal women (mean age 35.7±8.2 y). Individual dietary iron requirements were estimated using the Institute of Medicine calculations. A full probability approach was then applied to estimate the prevalence of dietary intakes that were insufficient to meet the needs of the men and women separately, based on their estimated daily iron intake and a series of absorption values ranging from 1–40%. The prevalence of SF concentrations below selected cut-off values (indicating that absorption was not high enough to maintain iron stores) was derived from individual SF concentrations. An estimate of dietary iron absorption required to maintain specified SF values was then calculated by matching the observed prevalence of insufficiency with the prevalence predicted for the series of absorption estimates. Mean daily dietary iron intakes were 13.5 mg for men and 9.8 mg for women. Mean calculated dietary absorption was 8% in men (50th percentile for SF 85 µg/L) and 17% in women (50th percentile for SF 38 µg/L). At a ferritin level of 45 µg/L estimated absorption was similar in men (14%) and women (13%). This new method can be used to calculate dietary iron absorption at a population level using data describing total iron intake and SF concentration

Response of finite spin-S Heisenberg chains to local perturbations

We consider the properties of finite isotropic antiferromagnetic Heisenberg chains with S=1/2, 1, 3/2 spins when a weak magnetic field is applied on a few sites, using White's density matrix renormalization group (DMRG) method. For the S=1 chain there exists only one length scale in the system which determines the behavior of the one- and two-point correlation functions both around the local perturbation and near the free boundary. For the critical, half-odd-integer spin cases the exponent of the spin-spin correlation function was found to be $\eta=1$, and the exponent of the decay of the site magnetization around the perturbed site is $x_m =\eta /2$. Close to a free boundary, however, the behavior is completely different for S=1/2 and $S > 1/2$.Comment: 13 pages, 7 figure

Nottingham Health Profile and Short-Form 36 Health Survey questionnaires in patients with chronic lower limb ischemia: Before and after revascularization

AbstractObjective: The purpose of this study was to compare the usefulness of the Nottingham Health Profile (NHP) and the Short-Form 36 Health Survey (SF-36) as general outcome measures after vascular intervention for lower limb ischemia with respect to patients' quality of life, on the basis of validity, reliability, and responsiveness analyses. Patients and Methods: Eighty patients, 40 with claudication and 40 with critical ischemia, were assessed before and one month after revascularization by using comparable domains of the NHP and the SF-36 questionnaires. Results: The SF-36 scores were less skewed and were distributed more homogeneously than the NHP scores. Discriminate validity results showed that NHP was better than SF-36 in discriminating among levels of ischemia with respect to pain and physical mobility. For both questionnaires, the reliability standards were satisfactory in most respects. The NHP was more responsive than the SF-36 in detecting within-patient changes. All of the NHP domains not zero at baseline were improved significantly one month after hemodynamically successful revascularization for patients with claudication, whereas patients with critical ischemia showed significant abatement of pain and improvements in physical mobility and social isolation. The SF-36 scores indicated a significant decrease in bodily pain and improvements in physical functioning and vitality for patients with claudication, and decrease in bodily pain and improvement in physical functioning for patients with critical ischemia. Conclusions: The findings indicated that both NHP and SF-36 were reliable. The SF-36 scores were less skewed than the NHP scores, whereas NHP discriminated better among levels of ischemia and was more responsive in detecting quality-of-life changes over time than SF-36 in these particular patients. (J Vasc Surg 2002;36:310-7.

Numerical renormalization group study of the correlation functions of the antiferromagnetic spin-12\frac{1}{2} Heisenberg chain

We use the density-matrix renormalization group technique developed by White \cite{white} to calculate the spin correlation functions $=(-1)^l \omega(l,N)$ for isotropic Heisenberg rings up to $N=70$ sites. The correlation functions for large $l$ and $N$ are found to obey the scaling relation $\omega(l,N)=\omega(l,\infty)f_{XY}^{\alpha} (l/N)$ proposed by Kaplan et al. \cite{horsch} , which is used to determine $\omega(l,\infty)$. The asymptotic correlation function $\omega(l,\infty)$ and the magnetic structure factor $S(q=\pi)$ show logarithmic corrections consistent with $\omega(l,\infty)\sim a\sqrt{\ln{cl}}/l$, where $c$ is related to the cut-off dependent coupling constant $g_{eff}(l_0)=1/\ln(cl_0)$, as predicted by field theoretical treatments.Comment: Accepted in Phys. Rev. B. 4 pages of text in Latex + 5 figures in uuencoded form containing the 5 postscripts (mailed separately