Initial Vacuum Magnetic Field Mapping in the Compact Toroidal Hybrid

The Compact Toroidal Hybrid (CTH) is a low aspect ratio (R/a_plasma ≥ 3.5, R₀ = 0.75 m, a_vessel = 0.29 m, B ≤ 0.6 T) torsatron with a highly flexible vacuum magnetic field configuration designed for current-driven instability studies. Vacuum magnetic field mapping of the completed configuration is performed using a movable electron gun and phosphor-coated screen. These experiments compare the actual magnetic configuration with the design, verify the range of accessible magnetic configurations, and identify vacuum field errors. The main helical field is produced by a continuously-wound helical coil, and the vacuum rotational transform is varied with a set of toroidal field coils. Four independent poloidal field coil sets provide equilibrium control and shaping, and are also used for ohmic current drive.     

Classical conditioning of the rabbit eyelid response with a mossy-fiber stimulation CS: II. Lateral reticular nucleus stimulation.

Stimulation of mossy fibers arising from the pontine nuclei can be used as a conditioned stimulus (CS) during classical conditioning of the eyelid/nictitating membrane response (NM). In the present experiment we stimulated another source of mossy fibers, the lateral reticular nucleus (LRN), as a CS for NM conditioning. LRN stimulation was an effective CS, resulting in learning, and the conditioned response to LRN stimulation showed normal extinction. Unpaired presentation of CS and US did not result in pseudo-conditioning. Lesions of the cerebellar dentate-interpositus region abolished the conditioned response but left the unconditioned reflex response intact. We suggest that mossy fibers may normally carry CS information to the cerebellum. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multimodal image fusion for noninvasive epilepsy surgery planning

A neurodiagnostic workstation integrated into a hospital picture archiving and communication system supports low cost, low risk epilepsy surgery planning by combining biomedical information from four neuroimaging modalities. This medical workstation aims to provide an environment for optimal interpretation of multiple noninvasive image modalities by combining functional PET, MRS, and MEG information with structural MRI anatomy both qualitatively and quantitatively. Since there is currently little knowledge relating to the positive and negative findings of various imaging and intracranial EEG studies on patient populations, the data extracted will also help in outcome analyses to identify inefficient or duplicative evaluation procedures     

Effect of wastewater spray irrigation on rotavirus infection rates in an exposed population

The Lubbock Infection Surveillance Study was conducted between June 1980 and October 1983 to detect potential increases in enteric infection and disease incidence in a community surrounding a wastewater spray irrigation site. This report concerns the incidence of rotavirus infections in study participates during that period. Rotavirus infection was defined as a > 2-fold increase in rotavirus serum antibody between blood collections which occurred approximately every 6 months. Antibody was detected by an enzyme-linked immunosorbent assay (ELISA). Of the 368 participants who provided 2 blood specimens, 67 seroconversions to rotavirus were detected, an average annual rate of 6.8 infections/100 subjects. One subject was infected twice. Seroconversions were observed in 32.7% (32/98) of children 16 years of age and in 12.7% (33/260) of adults ( 17 years old) with a single infection. Thus, significantly more (P < 0.0001) rotavirus infections occurred in children. Baseline rotavirus serum antibody titers were found to be significantly lower (P = 0.047) in subjects who seroconverted. However, many children and adults with high titers were also infected. More seroconversions were observed between June and December (January) than between December (January) and June. Wastewater spray irrigation had no detectable effect on the incidence of rotavirus infection.     

Nitrogen and phosphorus retention and excretion in late-gestation dairy heifers

The objectives of this study were to evaluate the effects of limit feeding diets containing concentrates or by-products in place of forages on manure and nutrient excretion in growing, gravid heifers. Eighteen Holstein heifers confirmed pregnant were grouped by due date and fed 1 of 3 diets (n = 6 per treatment) for the last 14 wk of pregnancy. Diets were high forage, fed ad libitum (HF); by-product based (BP), fed at the same rate as HF-fed heifers; or low forage (LF), fed at 86% of the HF diet. Diets were designed to supply equal quantities of P, N, and metabolizable energy. Total collection of feces and urine was conducted in wk 14, 10, 6, and 2 prepartum. The HF ration was 90.7% forage, 13.7% crude protein (CP), and contained orchardgrass hay, corn silage, corn grain, soybean meal 44%, and a vitamin-mineral premix. The BP diet was 46.2% forage and 14.0% CP, with 70% of the grain mix space replaced with soybean hulls and cottonseed hulls in a 1:1 ratio, with intake limited to 93% of the dry matter intake (DMI) of HF. The LF ration was 45.3% forage and 17.8% CP, with intake limited to 86% of the DMI of HF. The effect of diet was analyzed with repeated measures, using preplanned contrasts to compare HF with BP and LF with HF and BP. As designed, heifers fed HF and BP had greater DMI than the heifers limit-fed LF, and there was no effect of diet on average daily gain or BW. Intake and digestibility of N were lower, and fecal N excretion was higher, in heifers fed HF and BP than heifers fed LF. Mean feces excretion on both a wet and dry basis was greater for HF heifers compared with BP heifers and less for LF heifers than for HF and BP heifers. Despite differences in urinary output, diet had no effect on urea N excretion, but there was a trend for heifers fed HF and BP rations to excrete less urinary N compared with those fed LF. Compared with HF and BP heifers, LF heifers tended to have lower fecal P excretion and had higher urinary P excretion. Measured manure and urine excretion from heifers fed LF was greater than current American Society of Agricultural and Biological Engineers values, whereas heifers fed HF excreted less manure and urine than predicted. Heifers achieving similar rates of gain from diets differing in forage, grain, and by-product content excreted widely varying quantities of manure.     

Invited review: Sustainability of the US dairy industry

The US dairy industry has realized tremendous improvements in efficiencies and milk production since the 1940s. During this time, farm and total cow numbers have decreased and average herd size has increased. This intensification, combined with the shift to a largely urban public, has resulted in increased scrutiny of the dairy industry by social and environmental movements and increased concern regarding the dairy industry’s sustainability. In response to these concerns, a group of scientists specializing in animal welfare, nutrient management, greenhouse gas emissions, animal science, agronomy, agricultural engineering, microbiology, and economics undertook a critical review of the US dairy industry. Although the US dairy system was identified as having significant strengths, the consensus was that the current structure of the industry lacks the resilience to adapt to changing social and environmental landscapes. We identified several factors affecting the sustainability of the US dairy industry, including climate change, rapid scientific and technological innovation, globalization, integration of societal values, and multidisciplinary research initiatives. Specific challenges include the westward migration of milk production in the United States (which is at odds with projected reductions in precipitation and associated limitations in water availability for cattle and crops), and the growing divide between industry practices and public perceptions, resulting in less public trust. Addressing these issues will require improved alignment between industry practices and societal values, based upon leadership from within the industry and sustained engagement with other interested participants, including researchers, consumers, and the general public.     

Cluster characteristics of Geldart group B particles in a pilot-scale CFB riser. II. Polydisperse systems

Experiments with a focus on the impact of polydispersity on clustering characteristics (namely, appearance probability, duration, and frequency) of Geldart Group B particles in a circulating fluidized bed (CFB) riser have been performed. Three mixtures are considered: (i) a density-difference binary mixture, with species of different material density (ρ_s) but similar particle sizes (d_ave), (ii) a size-difference binary mixture, with species of different d_ave but similar material density ρ_s, and (iii) a continuous particle size distribution (PSD). Local cluster information spanning the entire riser was obtained over a range of operating conditions using a fiber optic probe. Results show that cluster trends for the binary mixtures are similar to those reported in the companion work for monodisperse materials (Chew et al., this issue) on two counts. First, local riser position has a significant influence on all three cluster characteristics, while effects of operating condition and material type are secondary. Second, among the three cluster characteristics, the cluster appearance probability is most influenced by local position, and least affected by operating condition and material type. Furthermore, the density-difference binary mixture exhibits a distinctly lower cluster duration than either of its constituent components. In contrast, the size-difference binary mixture has a cluster duration profile that mimics one constituent component, while the frequency profile mimics the other. Comparing the two binary mixtures at any riser location, the density-difference binary mixture has lower cluster duration and higher frequency than the size-difference binary mixture regardless of local position. Finally, with respect to the continuous PSD, which was investigated under a wider range of operating conditions, the effect of operating condition is more apparent. This deviation may be due to an inherent behavioral difference between binary mixture and continuous PSD and/or to the wider range of operating conditions examined.     

Two-dimensional transient numerical simulation of solids and gas flow in the riser section of a circulating fluidized bed

A computational fluid dynamics software (CFX) was modified for gas/particle flow systems and used to predict the flow parameters in the riser section of a circulating fluidized bed (CFB). Fluid Catalytic Cracking (FCC) particles and air were used as the solids and gas phases, respectively. Two-dimensional, transient, isothermal flows were simulated for the continuous phase (air) and the dispersed phase (solid particles). Conservation equations of mass and momentum for each phase were solved using the finite volume numerical technique. Two-dimensional gas and particle flow profiles were obtained for the velocity, volume fraction, and pressure drop for each phase. Calculations showed that the inlet and exit conditions play a significant role in the overall mixing of the gas and particulate phases and in the establishment of the flow regime. The flow behavior was analyzed based on the different frequency of oscillations in the riser. Comparison of the calculated solids mass flux, solids density and pressure drop with the measured pilot-scale PSRI data (reported in this paper) showed a good agreement.     

Short communication: Analysis of immune function in lactating dairy cows fed diets varying in phosphorus content

The aim of this study was to evaluate the effect of varying dietary P on bovine immune function. Nine first- or second-lactation Holstein cows were fed diets varying in P in a 3 × 3 Latin square design. Diets were formulated to contain either low (0.34%, no supplementary P), medium (0.43%), or high (0.52%) P. All 3 diets were formulated to meet or exceed current NRC requirements for P content. Between d 21 and 26 of each period, blood samples were collected and serum inorganic P concentration, lymphocyte proliferation, and neutrophil bactericidal activity were measured. Serum P increased with increasing dietary P intake and was greatest in the first lactation compared with subsequent lactations. There was a stage of lactation-dependent increase in lymphocyte proliferation after stimulation with concanavalin A, phytohemagglutinin, or pokeweed mitogen. However, dietary P did not alter lymphocyte proliferation or neutrophil bactericidal activity in vitro. In conclusion, decreasing dietary P to reduce manure P content and the risk of P losses from farms to surface water does not have an adverse effect on the innate or cell-mediated immune responses of lactating dairy cattle.     

A model of phosphorus digestion and metabolism in the lactating dairy cow

A dynamic, mechanistic, compartmental model of phosphorus (P) digestion and metabolism was constructed in the Advanced Continuous Simulation Language using conservation of mass principles and mass action kinetics. Phosphorus was assumed to exist in 3 forms: inorganic (Pi), phytic acid (Pp), and organic (excluding phytic acid; Po). All 3 forms were assumed to be present in the digestive tract with absorption of Pi into blood. Inputs to the model were total P intake; Pp, Po, and Pi as proportions of total P; milk yield; rate of salivation (fixed at 239 L/d); and rate of liquid passage from the rumen (fixed at 198 L/d). The model was fitted to 2 experiments from the literature. Derived parameters were well defined by the data. With a mean observed P intake of 75 g/d, total tract P digestibility was 38%. Phytic acid P digestibility in the rumen was 74%, with no additional Pp digestion in the lower tract. Inorganic P and Po digestibility in the lower tract were 48 and 89%, respectively. Flows of Po and Pi from the rumen were 2.4 and 3.0 times greater than intake, respectively. The increase in Po was apparently due to microbial growth. The increase in Pi arose primarily from secretion of Pi into the rumen via salivation where 65% of absorbed P was recycled to the rumen. Milk synthesis used 30% of absorbed Pi, and 1% was excreted in urine. This research suggested that the primary regulation points for maintaining blood P were bone deposition and resorption and absorption from the intestine. However, because bone P balance was related to both dietary P intake and ruminal phytase activity, it is critical to achieve a better understanding of phytate digestibility across several feeds if dietary P is to be reduced below current requirements.