Unusual Near-Horizon Cosmic-Ray-like Events Observed by ANITA-IV.

ANITA's fourth long-duration balloon flight in 2016 detected 29 cosmic-ray (CR)-like events on a background of 0.37_{-0.17}^{+0.27} anthropogenic events. CRs are mainly seen in reflection off the Antarctic ice sheets, creating a phase-inverted waveform polarity. However, four of the below-horizon CR-like events show anomalous noninverted polarity, a p=5.3×10^{-4} chance if due to background. All anomalous events are from locations near the horizon; ANITA-IV observed no steeply upcoming anomalous events similar to the two such events seen in prior flights.

Observation of an Unusual Upward-Going Cosmic-Ray-like Event in the Third Flight of ANITA.

We report on an upward traveling, radio-detected cosmic-ray-like impulsive event with characteristics closely matching an extensive air shower. This event, observed in the third flight of the Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload, is consistent with a similar event reported in a previous flight. These events could be produced by the atmospheric decay of an upward-propagating τ lepton produced by a ν_{τ} interaction, although their relatively steep arrival angles create tension with the standard model neutrino cross section. Each of the two events have a posteriori background estimates of ≲10^{-2} events. If these are generated by τ-lepton decay, then either the charged-current ν_{τ} cross section is suppressed at EeV energies, or the events arise at moments when the peak flux of a transient neutrino source was much larger than the typical expected cosmogenic background neutrinos.

Accelerator Measurements of Magnetically Induced Radio Emission from Particle Cascades with Applications to Cosmic-Ray Air Showers.

For 50 years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (rf) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of rf emission, which are relied upon in ultrahigh-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm modern predictions that the magnetically induced emission in a dielectric forms a cone that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.

Parameter and process significance in mechanistic modeling of cellulose hydrolysis.

A process-based model relevant to landfill and anaerobic digesters was developed, which included a novel approach to biomass transfer between a cellulose-bound biofilm and biomass in the bulk liquid. Model results highlighted the significance of the bacterial colonization of cellulose particles by attachment through contact in solution. Simulations revealed that both enhanced colonization and cellulose degradation are associated with reduced cellulose particle size, increased biomass populations in solution and increased cellulose-binding ability of the biomass. This suggests that transportation of biomass into the system from elsewhere and/or bacterial inoculation of such systems could enhance degradation significantly. A sensitivity analysis of the system parameters revealed the biological rate and yield properties of the hydrolyzing bacteria are most significant with regard to cellulose degradation in the system.

Biological fate of fumonisin B1 in food-producing animals.

The presence of mycotoxins in grains and feedstuffs causes not only animal health problems, but also a valid concern about the transmission of potentially toxic residues into animal-derived products intended for human consumption. In a series of studies at Agriculture and Agri-Food Canada, we investigated the biological fate of fumonisin B1 (FB1) in several food-producing animals (grower pigs, laying hens, dairy cattle), as well as monitored various parameters for evidence of toxicity in these species. In several experiments involving either single-dose protocols (iv, po) or longer-term feeding trials, the pharmacokinetic profiles of FB1 (purity > 95%) in these species were determined, including tissue accumulation and transmission of residues. Toxicological (and economical) implications such as performance (feed consumption, growth), productivity, and carcass quality were also measured when appropriate.

Sudden death syndrome in broilers: dietary fat supplementation and its effect on tissue composition.

The effects of dietary fat sources on the general performance of broiler chickens and the incidence of sudden death syndrome (SDS) were investigated in two experiments. In Experiment 1, a wheat-soy diet supplemented with sunflower oil was found to improve significantly (P less than .05) performance characteristics and reduce the mortality attributed to SDS as compared with the same diet supplemented with tallow. The blood lipid parameters--total lipids, triglycerides, and cholesterol at 4 and 7 weeks of age--were not affected (P greater than .05) by the type of fat used in the diet. In Experiment 2, wheat-soy diets were supplemented with either tallow or sunflower oil at the same dietary levels and two stocking densities (.09 m2/bird or .08 m2/bird). The sunflower oil diet significantly (P less than .05) improved the general performance of the birds and reduced mortality from SDS. Bird density had no significant effect. Fatty acid composition of the heart and liver tissues from SDS birds showed differences when compared with culled birds (leg problems) from the same experimental period. In the heart tissue, increased palmitic (16:0) and oleic (18:1) acids were observed, while linoleic (18:2) and arachidonic (20:4) acids were lower. Liver tissue showed increased 18:1 and lower 18:2 and 20:4. Analysis for copper and zinc in heart tissue did not indicate significant (P greater than .05) treatment effects, but calcium concentration was significantly (P greater than .05) higher in SDS than culled birds. Analysis performed on the liver tissue showed significant (P lesser than .05) differences in copper and zinc between these two groups of birds.

The effects of enzyme supplementation on the nutritive value of rye grain (Secale cereale) for the young broiler chick.

Two dose-response experiments utilizing differing enzyme concentrations were carried out to determine the level of a crude enzyme preparation (Trichoderma viride cellulase) required to obtain maximum growth performance in young broiler chicks fed a 60% rye diet. Enzyme concentrations utilized in these studies ranged from .05 to 12.8 g enzyme/kg diet. Enzyme supplementation at the 3.2 g/kg diet level yielded increases in feed consumption and weight gain of 71 and 193%, respectively; and the feed to gain ratio was improved by 43% compared with that for the unsupplemented rye control diet. As no further growth response was obtained by increasing the enzyme concentration, the enzyme level utilized in a subsequent study was 3.2 g/kg diet. A balance study using 2-wk-old broiler chicks was carried out to determine the effect of enzyme supplementation on the bioavailable energy (AMEn) and apparent protein digestibility (APD) of a 60% wheat diet replaced by rye in 10% increments. In the 60% rye diets, the enzyme addition increased the dietary AMEn and APD by 23 and 12%, respectively, compared with the unsupplemented diet. The AMEn and APD of the 60% wheat control diet were increased 9.7 and 4.6%, respectively, by enzyme addition. The data suggest that the AMEn of rye grain is increased by enzyme supplementation; however, alternate methodology will have to be employed to quantitatively determine the extent of these improvements.

The effect of enzyme supplementation on the apparent metabolizable energy and nutrient digestibilities of wheat, barley, oats, and rye for the young broiler chick.

The influence of enzyme supplementation on the bioavailable energy (AME(n)) and apparent digestibilities of lipid (ALD) and protein (APD) in young broiler chicks was examined for diets containing either wheat, hulled or hulless barley, naked oats, or spring rye. Dietary AME(n), APD, and ALD values were depressed (P less than or equal to .01) for all test grains (except hulled Bedford barley) as the inclusion rate of the grain replacing wheat increased. The antinutritives, beta-glucans (barley and oats) and pentosans (rye), had the most pronounced effect on ALD. The decreases in ALD were 43, 77, and 67% for chicks fed diets containing 70% Scout barley (hulless), Terra oats, and Gazelle rye, respectively, compared with those fed the control wheat diet. Enzyme supplementation increased (P less than or equal to .01) AME(n), APD, and ALD for all test cereals. The corresponding increases in the AME(n), of the enzyme-supplemented diets containing 70% HY320 wheat, Bedford barley, Scout barley, Terra oats, and Gazelle rye diets were 4, 7, 42, 33, and 14%, respectively, compared with their unsupplemented counterparts. Enzyme treatment also improved (P less than or equal to .01) weight gains and feed conversion efficiencies of chicks fed diets containing each of the cereals. Overall, the results demonstrate that the nutritive value of cereal grains such as wheat, barley, oats, and rye can be improved by the addition of crude fungal extracts to the diet of young chicks.

Effect of enzyme supplementation on the nutritional value of raw, autoclaved, and dehulled lupins (Lupinus albus) in chicken diets.

The effects of adding crude enzyme preparations to diets containing raw, autoclaved, and dehulled lupin seeds on the performance of broiler and Leghorn chicks (7 to 21 days) were evaluated in five experiments. In the first experiment, enzyme addition (combination of Energex-carbohydrase, Bio-Feed Pro-protease, and Novozyme-alpha-galactosidase) to a diet containing 70% raw lupins improved the weight gain and feed to gain ratio of broiler chicks by 18 and 10%, respectively. The relative intestinal length and gizzard weight also were reduced by enzyme treatment. In the second experiment, the optimum concentration of enzymes was determined in diets containing 50% raw lupins. Bio-Feed Pro at 3% increased weight gains by 24% and the feed to gain ratio by 11%, whereas a combination of three enzymes at .10% of each yielded respective improvements of 18 and 9%. In Experiment 3, the AME and protein digestibility of dehulled lupin seeds were increased by 18 and 7% compared with those for raw seeds. Autoclaving (20 min) significantly (P < .05) improved chick performance and AME and protein digestibility of raw seeds. In the fourth experiment, autoclaving (15 min), dehulling, and a combination of both improved weight gains by 11, 15, and 8% and feed to gain ratios by 4, 11, and 6%, respectively. Enzyme addition improved the performance of birds fed raw, but not autoclaved lupin diets. In the fifth experiment, dehulling and enzyme treatment but not autoclaving (20 min) improved the performance of birds fed diets containing 50% lupins. The relative weight of gizzard was reduced by both treatments but that of the pancreas was affected only by enzyme treatment. Overall, enzyme supplementation of raw lupin diets considerably improved chick performance. Dehulling of lupins also improved chick performance with results for autoclaved lupins being inconsistent.

Estimation of nitrogen-corrected true metabolizable energy of two different barley samples with and without enzyme supplementation over different excreta collection times.

The TMEn values of two barley samples and a corn sample with and without enzyme addition were determined in an experiment conducted over two consecutive weekly periods. Adult roosters were not influenced by the high beta-glucan content of Scout barley, which had a higher energy value (3.70 kcal/g DM) than the Bedford barley (3.44 kcal/g DM). Overall the energy value of the grain increased 3% due to enzyme supplementation. The 48-h excreta collection time was considered to be adequate for TMEn determination.

Estimation of apparent protein digestibility using uric acid-corrected nitrogen values in poultry excreta.

Apparent protein digestibility values were calculated using three methods based on nitrogen digestibility, corrected and uncorrected for uric acid and amino acid digestibility. Amino acid digestibility, as determined by the summation of individual amino acid values, excluding methionine and cystine (81.2%), closely approximated protein digestibility values derived from nitrogen corrected for uric acid (81.4%). Uncorrected nitrogen values gave misleading results (38.4%). Apparent protein digestibility values, when corrected for uric acid, appear to provide a simple and reliable method for estimating protein digestibility.

Mycotoxin fumonisin B1 stimulates nitric oxide production in a murine macrophage cell line.

Fumonisin B1 (FB1), a mycotoxin, is a common fungal contaminant of corn and corn products. This sphingolipid-like compound causes a variety of animal diseases and is a suspected human carcinogen. Cellular targets of FB1 include hepatocytes and renal and immune cells. The effects of FB1 on nitric oxide (NO) production induced by lipopolysaccharide (LPS) were investigated in the present study by using a murine macrophage cell line as a model system. Stimulation of NO production was observed for increasing concentrations of FB1 (1, 10, and 100 microM) and either 0.005 or 0.01 microgram/ml LPS. Although with an increasing dose of FB1 the total protein content decreased for the stimulated and the unstimulated cells, the NO production remained elevated for the stimulated cells. It can be hypothesized that the potentiation of the LPS-dependent NO production by FB1 treatment could be due to direct interaction between FB1 and NO synthases and LPS receptors or to a disrupted sphingolipid metabolism.

Stability of the Le Fort I maxillary osteotomy after rigid internal fixation.

PURPOSE: The purpose of this study was to evaluate the postsurgical stability of the Le Fort I osteotomy with impaction in which rigid internal fixation was used for stabilization. MATERIALS AND METHODS: Lateral cephalograms of 19 patients were evaluated. Descriptive statistics were compiled that included absolute linear and angular measurements as well as absolute changes in measurements for successive cephalometric radiographs. Comparisons were made from 1) presurgery to immediate postsurgery, 2) immediate postsurgery to splint removal, 3) splint removal to longest follow-up, and 4) immediate postsurgery to longest follow-up. Repeated measures analysis of variance were used to describe significant differences for absolute changes in measurements. RESULTS: All surgical movements were significant except for horizontal position of dental structures, horizontal position of the posterior mandible, and posterior vertical facial height. All significant movement from immediate postsurgery to splint removal was secondary to removal of the occlusal splint. Changes were minimal from splint removal to longest follow-up, with only 3 of 24 measurements showing statistically significant differences. These measurements related to tooth position and were affected by postsurgical orthodontics. The data derived from this study were also compared with those found in similar studies in which fixation was by wire osteosynthesis. CONCLUSIONS: The magnitude of postoperative movement was considerably less with rigid internal fixation than that reported with the use of wire fixation. This is attributed to the increased stabilizing effect of rigid internal fixation.

Testing progressive loading of endosteal implants with the Periotest: a pilot study.

The progressive loading of implants was first suggested by Misch in 1980. A major indicator of successful osseointegration is lack of implant mobility. In a pilot study, 26 implants were placed in eight patients. Fifteen of the implants were progressively loaded before placement of the final restorations. The remaining 11 implants were allowed to heal with healing abutments only and were not loaded until placement of the final restorations. Three measurements were taken for each of the implants at the time of uncovering and at the final restoration appointment using the Periotest. The mean change in Periotest values was -0.27 for the non-loaded group as compared with -1.51 for the progressively loaded group. There was a significantly larger increase (P < 0.001) in implant rigidity for the progressively loaded group. Progressive loading appears to enhance implant rigidity. The Periotest has the potential of being a valuable instrument for the determination of osseointegration.

The role of tryptophan in DON-induced feed rejection.

Deoxynivalenol (DON, vomitoxin) commonly produced by Fusarium fungi can alter feeding behaviour of pigs and other farm animals. The effects of dietary tryptophan (TRP, precursor of brain amine serotonin) in combination with DON were examined in mice to determine if TRP can modulate DON toxicity. Results indicated that brain TRP can be influenced by dietary TRP, but no evidence of TRP potentiating DON toxicity was observed. Higher TRP levels likely induced amino acid imbalance leading to weight gain suppression.

Toxicology of deoxynivalenol (vomitoxin).

Trichothecene mycotoxins are a group of structurally similar fungal metabolites that are capable of producing a wide range of toxic effects. Deoxynivalenol (DON, vomitoxin), a trichothecene, is prevalent worldwide in crops used for food and feed production, including in Canada and the United States. Although DON is one of the least acutely toxic trichothecenes, it should be treated as an important food safety issue because it is a very common contaminant of grain. This review focuses on the ability of DON to induce toxicologic and immunotoxic effects in a variety of cell systems and animal species. At the cellular level, the main toxic effect is inhibition of protein synthesis via binding to the ribosome. In animals, moderate to low ingestion of toxin can cause a number of as yet poorly defined effects associated with reduced performance and immune function. The main overt effect at low dietary concentrations appears to be a reduction in food consumption (anorexia), while higher doses induce vomiting (emesis). DON is known to alter brain neurochemicals. The serotoninergic system appears to play a role in mediation of the feeding behavior and emetic response. Animals fed low to moderate doses are able to recover from initial weight losses, while higher doses induce more long-term changes in feeding behavior. At low dosages of DON, hematological, clinical, and immunological changes are also transitory and decrease as compensatory/adaptation mechanisms are established. Swine are more sensitive to DON than mice, poultry, and ruminants, in part because of differences in metabolism of DON, with males being more sensitive than females. The capacity of DON to alter normal immune function has been of particular interest. There is extensive evidence that DON can be immunosuppressive or immunostimulatory, depending upon the dose and duration of exposure. While immunosuppression can be explained by the inhibition of translation, immunostimulation can be related to interference with normal regulatory mechanisms. In vivo, DON suppresses normal immune response to pathogens and simultaneously induces autoimmune-like effects which are similar to human immunoglobulin A (IgA) nephropathy. Other effects include superinduction of cytokine production by T helper cells (in vitro) and activation of macrophages and T cells to produce a proinflammatory cytokine wave that is analogous to that found in lipopolysaccharide-induced shock (in vivo). To what extent the elevation of cytokines contributes to metabolic effects such as decreased feed intake remains to be established. Although these effects have been largely characterized in the mouse, several investigations with DON suggest that immunotoxic effects are also likely in domestic animals. Further toxicology studies and an assessment of the potential of DON to be an etiologic agent in human disease are warranted.

Effect of the appetite stimulant cyproheptadine on deoxynivalenol-induced reductions in feed consumption and weight gain in the mouse.

Deoxynivalenol (DON, vomitoxin), a Fusarium mycotoxin, is suspected of inducing its anorectic/feed refusal activity through a serotoninergic (5HT) mechanism, possible via 5HT2-receptors. In this study the efficiency of cyproheptadine (CYP), a serotonin antagonist and known appetite stimulant, to attenuate the adverse effect of DON was investigated in mice. CYP was administered in the feed for two days before animals began receiving the DON, which was also added to the feed. Both agents were administered concurrently thereafter for a 12-day period. Dosing levels included various combinations of the two compounds, ranging from 0-16 ppm DON and 0-20 ppm CYP.

Evaluation of potential interactions involving trichothecene mycotoxins using the chick embryotoxicity bioassay.

The Chick Embryotoxicity Screening Test (CHEST) was used to examine possible interactions between different trichothecenes. Combinations of deoxynivalenol (DON), 15-acetyldeoxynivalenol (15-ADON) and HT-2 toxin were tested at various concentrations and the effects were determined based on percent mortality. The combined toxicity of any two trichothecenes was found to be additive. Discrepancies between observed and expected mortality values seldom differed by more than 10%, well within sampling error for the binomial distribution. Several limitations of the CHEST assay are discussed.