Creation and Characterization of Matter-Wave Breathers.

We report the creation of quasi-1D excited matter-wave solitons, "breathers," by quenching the strength of the interactions in a Bose-Einstein condensate with attractive interactions. We characterize the resulting breathing dynamics and quantify the effects of the aspect ratio of the confining potential, the strength of the quench, and the proximity of the 1D-3D crossover for the two-soliton breather. Furthermore, we demonstrate the complex dynamics of a three-soliton breather created by a stronger interaction quench. Our experimental results, which compare well with numerical simulations, provide a pathway for utilizing matter-wave breathers to explore quantum effects in large many-body systems.

Measurement of the Dynamical Structure Factor of a 1D Interacting Fermi Gas.

We present measurements of the dynamical structure factor S(q,ω) of an interacting one-dimensional Fermi gas for small excitation energies. We use the two lowest hyperfine levels of the ^{6}Li atom to form a pseudospin-1/2 system whose s-wave interactions are tunable via a Feshbach resonance. The atoms are confined to one dimension by a two-dimensional optical lattice. Bragg spectroscopy is used to measure a response of the gas to density ("charge") mode excitations at a momentum q and frequency ω, as a function of the interaction strength. The spectrum is obtained by varying ω, while the angle between two laser beams determines q, which is fixed to be less than the Fermi momentum k_{F}. The measurements agree well with Tomonaga-Luttinger theory.

Lower prevalence of antibiotic-resistant Salmonella on large-scale U.S. conventional poultry farms that transitioned to organic practices.

As a result of the widespread use of antibiotics in large-scale U.S. poultry production, a significant proportion of Salmonella strains recovered from conventional poultry farms and retail poultry products express antibiotic resistance. We evaluated whether large-scale poultry farms that transitioned from conventional to organic practices and discontinued antibiotic use were characterized by differences in the prevalence of antibiotic-resistant Salmonella compared to farms that maintained conventional practices. We collected poultry litter, water and feed samples from 10 newly organic and 10 conventional poultry houses. Samples were analyzed for Salmonella using standard enrichment methods. Isolates were confirmed using standard biochemical tests and the Vitek®2 Compact System. Antimicrobial susceptibility testing was performed by Sensititre® microbroth dilution. Data were analyzed using Fisher's exact test and generalized linear mixed models. We detected Salmonella in both conventional and newly organic poultry houses. Salmonella Kentucky was the predominant serovar identified, followed by S. Orion, S. Enteritidis, S. Gostrup and S. Infantis. Among S. Kentucky isolates (n=41), percent resistance was statistically significantly lower among isolates recovered from newly organic versus conventional poultry houses for: amoxicillin-clavulanate (p=0.049), ampicillin (p=0.042), cefoxitin (p=0.042), ceftiofur (p=0.043) and ceftriaxone (p=0.042). Percent multidrug resistance (resistance to ≥3 antimicrobial classes) was also statistically significantly lower among S. Kentucky isolates recovered from newly organic poultry houses (6%) compared to those recovered from conventional houses (44%) (p=0.015). To our knowledge, these are the first U.S. data to show immediate, on-farm changes in the prevalence of antibiotic-resistant Salmonella when antibiotics are voluntarily withdrawn from large-scale poultry facilities in the United States.

Metastability in spin-polarized Fermi gases.

We study the role of particle transport and evaporation on the phase separation of an ultracold, spin-polarized atomic Fermi gas. We show that the previously observed deformation of the superfluid paired core is a result of evaporative depolarization of the superfluid due to a combination of enhanced evaporation at the center of the trap and the inhibition of spin transport at the normal-superfluid phase boundary. These factors contribute to a nonequilibrium jump in the chemical potentials at the phase boundary. Once formed, the deformed state is highly metastable, persisting for times of up to 2 s.

Lower prevalence of antibiotic-resistant Enterococci on U.S. conventional poultry farms that transitioned to organic practices.

BACKGROUND: In U.S. conventional poultry production, antimicrobials are used for therapeutic, prophylactic, and nontherapeutic purposes. Researchers have shown that this can select for antibiotic-resistant commensal and pathogenic bacteria on poultry farms and in poultry-derived products. However, no U.S. studies have investigated on-farm changes in resistance as conventional poultry farms transition to organic practices and cease using antibiotics. OBJECTIVE: We investigated the prevalence of antibiotic-resistant Enterococcus on U.S. conventional poultry farms that transitioned to organic practices. METHODS: Poultry litter, feed, and water samples were collected from 10 conventional and 10 newly organic poultry houses in 2008 and tested for Enterococcus. Enterococcus (n = 259) was identified using the Vitek® 2 Compact System and tested for susceptibility to 17 antimicrobials using the Sensititre™ microbroth dilution system. Data were analyzed using SAS software (version 9.2), and statistical associations were derived based on generalized linear mixed models. RESULTS: Litter, feed, and water samples were Enterococcus positive. The percentages of resistant Enterococcus faecalis and resistant Enterococcus faecium were significantly lower (p < 0.05) among isolates from newly organic versus conventional poultry houses for two (erythromycin and tylosin) and five (ciprofloxacin, gentamicin, nitrofurantoin, penicillin, and tetracycline) antimicrobials, respectively. Forty-two percent of E. faecalis isolates from conventional poultry houses were multidrug resistant (MDR; resistant to three or more antimicrobial classes), compared with 10% of isolates from newly organic poultry houses (p = 0.02); 84% of E. faecium isolates from conventional poultry houses were MDR, compared with 17% of isolates from newly organic poultry houses (p < 0.001). CONCLUSIONS: Our findings suggest that the voluntary removal of antibiotics from large-scale U.S. poultry farms that transition to organic practices is associated with a lower prevalence of antibiotic-resistant and MDR Enterococcus.

High eggshell temperatures during incubation decrease growth performance and increase the incidence of ascites in broiler chickens.

High eggshell temperatures (EST; ≥38.9°C) during the second half of incubation are known to decrease the body and organ development of broiler hatchlings. In particular, relative heart weights are decreased by a high EST, and this may increase the incidence of metabolic disorders that are associated with cardiovascular development, such as ascites. The current study investigated the effects of a high EST on chick quality, subsequent performance, and the incidence of ascites later in life. Eggs were incubated at a normal (37.8°C) or high (38.9°C) EST from d 7 of incubation onward. After hatching, the chickens were housed per EST in pens, and a normal or cold temperature schedule was applied during the grow-out period. Hatchability, hatchling quality, BW, feed conversion ratio, total mortality, mortality associated with ascites, slaughter characteristics, and ascites susceptibility at 6 wk of age were evaluated. Except for total ventricle weight, no interaction was found between EST and the grow-out temperature. Hatchability was comparable between the EST treatments, but the percentage of second-grade chickens was 0.7% higher at the high EST. Yolk-free body mass was 3.0 g lower, and heart weights were 26% lower at hatch in the high compared with the normal EST treatment. Body weight continued to be less during the grow-out period after the high EST incubation. However, breast meat yield was 1.0% higher in the high than in the normal EST. Feed conversion ratio did not differ between EST treatments. Total mortality was 4.1% higher and mortality associated with ascites was 3.8% higher in the high compared with the normal EST treatment. The ratio between the right and total ventricle was 1.1% higher in the high compared with the normal EST treatment at slaughter age. In conclusion, a high EST from d 7 of incubation onward decreased hatchling quality and growth performance, but increased breast meat yield. Furthermore, high EST incubation increased the incidence of ascites, which may be related to the reduced heart development at hatch.

Effect of incubation temperature on nutrient transporters and small intestine morphology of broiler chickens.

This study evaluated the effects of elevated incubation temperature on posthatch nutrient transporter gene expression, integrity of the intestinal epithelium, organ development, and performance in Ross 308 broiler chickens. Ross × Ross 308 fertile eggs (n = 900) were incubated at different eggshell temperatures during development. From embryonic day (ED) 1 to ED12, all eggs were incubated at 37.1°C, whereas from ED13 to ED21, the eggs were divided into 2 groups for incubation at 37.4°C (S) or 39.6°C (H). Performance characteristics were measured at day of hatch (DOH) and d 7, 14, 21, 30, and 42. Small intestine and residual yolk sacs were collected at DOH and d 2, 4, 6, and 10 and weighed individually. Intestinal samples from the duodenum, jejunum, and ileum were evaluated for mucosal morphology and relative nutrient transporter gene expression. No significant differences were found in performance or organ weights. The intestinal morphology results showed a temperature × age interaction in duodenum villus height (P = 0.02) and crypt depth (P = 0.05) and in ileum villus height-to-crypt depth ratios (P = 0.02). There was a main effect of temperature, resulting in deeper crypts (P = 0.02) in the jejunum of chicks incubated at H compared with S. In the nutrient gene expression evaluation, peptide transporter (PepT1) showed a temperature × age interaction. On DOH and d 2, 4, and 10, PepT1 expression was similar between chicks incubated at S and H. However, on d 6, chicks incubated at S had significantly higher expression of PepT1 than those incubated at H. This study presents the effects of elevated incubation temperature on small intestine morphology and relative expression of nutrient transporter mRNA in high-yield broiler chicks, which can be important for the availability of nutrients and distribution of energy.

Dietary camelina meal versus flaxseed with and without supplemental copper for broiler chickens: live performance and processing yield.

An experiment was conducted to compare the responses of young broiler chickens to corn-soybean meal diets supplemented with flaxseed or camelina meal versus a corn-soybean meal control and the factorial effect of 150 mg/kg of Cu supplementation on performance and processing yield. A randomized complete block design with a 2 x 3 factorial arrangement was used with 7 replicates from hatch to 21 d of age (n = 294; 7 chicks per replicate). Body weight of birds fed 10% camelina meal or 10% flaxseed was significantly reduced compared with the control birds. Addition of Cu significantly increased BW and feed consumption of the birds fed the control diet throughout the study. Copper supplementation to the 10% camelina meal diet also increased BW (P < 0.001) with no effect on feed consumption or feed conversion at 21 d. In addition, hot carcass weight, yield, and carcass parts were significantly improved among birds fed the Cu-supplemented control diet. A significant Cu x diet interaction was observed for hot carcass weight and yield, indicating Cu supplementation to the control diet was superior for carcass weight to the other treatments. However, yield was greater for the camelina diets and the control + Cu versus the other treatments. Results from the present study demonstrated that either 10% camelina meal or 10% flaxseed diets will reduce broiler BW when fed the first 3 wk of life. However, birds fed the camelina diet responded to Cu sulfate supplementation with improved live performance and carcass characteristics. Birds fed the 10% flaxseed diets showed no beneficial effect resulting from Cu supplements.

Extreme tunability of interactions in a 7Li Bose-Einstein condensate.

We use a Feshbach resonance to tune the scattering length a of a Bose-Einstein condensate of 7Li in the |F=1,mF=1> state. Using the spatial extent of the trapped condensate, we extract a over a range spanning 7 decades from small attractive interactions to extremely strong repulsive interactions. The shallow zero crossing in the wing of the Feshbach resonance enables the determination of a as small as 0.01 Bohr radii. Evidence of the weak anisotropic magnetic dipole interaction is obtained by comparison with different trap geometries for small a.

Photoassociation of a Bose-Einstein condensate near a Feshbach resonance.

We measure the effect of a magnetic Feshbach resonance (FR) on the rate and light-induced frequency shift of a photoassociation resonance in ultracold 7Li. The photoassociation-induced loss-rate coefficient K_{p} depends strongly on magnetic field, varying by more than a factor of 10;{4} for fields near the FR. At sufficiently high laser intensities, K_{p} for a thermal gas decreases with increasing intensity, while saturation is observed for the first time in a Bose-Einstein condensate. The frequency shift is also strongly field dependent and exhibits an anomalous blueshift for fields just below the FR.

Vegetative buffers for fan emissions from poultry farms: 1. temperature and foliar nitrogen.

This study sought to evaluate the potential of trees planted around commercial poultry farms to trap ammonia (NH(3)), the gas of greatest environmental concern to the poultry industry. Four plant species (Norway spruce, Spike hybrid poplar, Streamco willow, and hybrid willow) were planted on eight commercial farms from 2003 to 2004. Because temperature (T) can be a stressor for trees, T was monitored in 2005 with data loggers among the trees in front of the exhaust fans (11.4 to 17.7 m) and at a control distance away from the fans (48 m) during all four seasons in Pennsylvania. Norway spruce (Picea abies) foliage samples were taken in August 2005 from one turkey and two layer farms for dry matter (DM) and nitrogen (N) analysis. The two layer farms had both Norway spruce and Spike hybrid poplar (Populus deltoides x Populus nigra) plantings sampled as well allowing comparisons of species and the effect of plant location near the fans versus a control distance away. Proximity to the fans had a clear effect on spruce foliar N with greater concentrations downwind of the fans than at control distances (3.03 vs. 1.88%; P < or = 0.0005). Plant location was again a significant factor for foliar N of both poplar and spruce on the two farms with both species showing greater N adjacent to the fans compared to the controls (3.75 vs. 2.32%; P < or = 0.0001). Pooled foliar DM of both plants was also greater among those near the fans (56.17, fan vs. 44.67%, control; P < or = 0.005). Species differences were also significant showing the potential of poplar to retain greater foliar N than spruce (3.52 vs. 2.55%; P < or = 0.001) with less DM (46.00 vs. 54.83%; P < or = 0.05) in a vegetative buffer setting. The results indicated plants were not stressed by the T near exhaust fans with mean seasonal T (13.04 vs. 13.03 degrees C, respectively) not significantly different from controls. This suggested poultry house exhaust air among the trees near the fans would not result in dormancy stressors on the plants compared to controls away from the fans.

Vegetative buffers for fan emissions from poultry farms: 2. ammonia, dust and foliar nitrogen.

This study evaluated the potential of trees planted around commercial poultry farms to trap ammonia (NH(3)) and dust or particulate matter (PM). Norway spruce, Spike hybrid poplar, hybrid willow, and Streamco purpleosier willow were planted on five commercial farms from 2003 to 2004. Plant foliage was sampled in front of the exhaust fans and at a control distance away from the fans on one turkey, two laying hen, and two broiler chicken farms between June and July 2006. Samples were analyzed for dry matter (DM), nitrogen (N), and PM content. In addition, NH(3) concentrations were measured downwind of the exhaust fans among the trees and at a control distance using NH(3) passive dosi-tubes. Foliage samples were taken and analyzed separately based on plant species. The two layer farms had both spruce and poplar plantings whereas the two broiler farms had hybrid willow and Streamco willow plantings which allowed sampling and species comparisons with the effect of plant location (control vs. fan). The results showed that NH(3) concentration h(- 1) was reduced by distance from housing fans (P < or = 0.0001), especially between 0 m (12.01 ppm), 11.4 m (2.59 ppm), 15 m (2.03 ppm), and 30 m (0.31 ppm). Foliar N of plants near the fans was greater than those sampled away from the fans for poplar (3.87 vs. 2.56%; P < or = 0.0005) and hybrid willow (3.41 vs. 3.02%; P < or = 0.05). The trends for foliar N in spruce (1.91 vs. 1.77%; P = 0.26) and Streamco willow (3.85 vs. 3.33; P = 0.07) were not significant. Pooling results of the four plant species indicated greater N concentration from foliage sampled near the fans than of that away from the fans (3.27 vs. 2.67%; P < or = 0.0001). Foliar DM concentration was not affected by plant location, and when pooled the foliar DM of the four plant species near the fans was 51.3% in comparison with 48.5% at a control distance. There was a significant effect of plant location on foliar N and DM on the two layer farms with greater N and DM adjacent to fans than at a control distance (2.95 vs. 2.15% N and 45.4 vs. 38.2% DM, respectively). There were also significant plant species effects on foliar N and DM with poplar retaining greater N (3.22 vs. 1.88%) and DM (43.7 vs. 39.9%) than spruce. The interaction of location by species (P < or = 0.005) indicated that poplar was more responsive in terms of foliar N, but less responsive for DM than spruce. The effect of location and species on foliar N and DM were not clear among the two willow species on the broiler farms. Plant location had no effect on plant foliar PM weight, but plant species significantly influenced the ability of the plant foliage to trap PM with spruce and hybrid willow showing greater potential than poplar and Streamco willow for PM(2.5)(0.0054, 0.0054, 0.0005, and 0.0016 mg cm(- 2); P < or = 0.05) and total PM (0.0309, 0.0102, 0.0038, and 0.0046 mg cm(- 2), respectively; P < or = 0.001). Spruce trapped more dust compared to the other three species (hybrid willow, poplar, and Streamco willow) for PM(10) (0.0248 vs. 0.0036 mg cm(- 2); P < or = 0.0001) and PM(> 10) (0.0033 vs. 0.0003 mg cm(- 2); P = 0.052). This study indicates that poplar, hybrid willow, and Streamco willow are appropriate species to absorb poultry house aerial NH(3)-N, whereas spruce and hybrid willow are effective traps for dust and its associated odors.

Managing incubation: where are we and why?

An improvement in the rate of gain of broilers during the past 20 yr has made the incubation period a larger percentage of the overall growth period for commercial poultry and has played a larger role in improving growth efficiency. Recently, hatchery managers have observed concomitant decreases in hatchability and chick performance, whereas temperature profiles in the setters and hatchers have not changed appreciably. Therefore, these decreases in hatchability, first week livability, hatch time, and overall chick quality have precipitated the need for a change in the way we manage our hatcheries. Historically, the broiler industry within the United States and United Kingdom have successfully utilized multistage incubation. Currently, the use of single-stage incubation in Europe has increased, because research has shown this system more precisely meets the developmental demands of the embryos. Therefore, research has focused on multi- and single-stage hatcheries to determine the proper hatch conditions necessary to optimize embryonic development, chick quality, and their effects on posthatch performance. Studies have shown how increases in shell temperature, independent of machine temperature, can result in increases in embryonic mortality, decreased heart weight as a percentage of chick weight, decreased yolk-free BW, and increased yolk weight. Factors that have contributed to the increase in heat stress on developing embryos include egg size, air flow, age of the embryo, and breeder flock fertility. Other studies have shown that the variation in chick performance can be explained by heat stress in the hatchery. Therefore, symposium presentations will show how improvements in our knowledge of the requirements of the developing avian embryo can help improve not only hatchability and first week livability but posthatch performance.

Influence of egg shell embryonic incubation temperature and broiler breeder flock age on posthatch growth performance and carcass characteristics.

A study was conducted to examine the posthatch growth performance of high-yielding broilers when eggs were incubated at 3 different embryo temperatures from 2 flocks of breeders at different ages (different egg size). Two thousand, four hundred eggs from 2 broiler breeder flocks (29 and 57 wk of age) of the same high-yielding strain (Cobb x Cobb) were incubated in the same incubator for 16 d at 37.5 degrees C. Following candling, the eggs from the 2 flocks were transferred into 3 hatcher cabinets at starting temperatures of 36.5 degrees C (low, L), 37.6 degrees C (middle, M), and 38.7 degrees C (high, H) and adjusted to achieve a shell temperature of 37.5 degrees C (L), 38.6 degrees C (M), and 39.7 degrees C (H) using an infrared thermometer. All chicks were taken off at 21 d of incubation, randomized into floor pens, and reared for 44 d. Body weights, feed intake, and feed conversion were determined at 21, 35, and 44 d of age. Body weight of birds from the H treatment was significantly less at 21, 35, and 44 d compared with the M birds. Birds in the L group weighed significantly less at 35 and 44 d compared with the M birds. Progeny from the older breeder flock had significantly greater BW at 1, 21, and 35 d of age, but had only numerically greater BW at 44 d when compared with birds from the younger flock. Feed conversion for the H birds was significantly higher from 0 to 21 d of age compared with the M and L birds. Broilers from the 29-wk-old breeder flock had lower cumulative feed conversion values than the birds from the 57-wk-old flock. No significant differences in mortality were observed. Posthatch performance appears to be affected by hatcher environment as determined by embryo shell temperature.

Deformation of a trapped Fermi gas with unequal spin populations.

The real-space densities of a polarized strongly interacting two-component Fermi gas of 6Li atoms reveal two low-temperature regimes, both with a fully paired core. At the lowest temperatures, the unpolarized core deforms with increasing polarization. Sharp boundaries between the core and the excess unpaired atoms are consistent with a phase separation driven by a first-order phase transition. In contrast, at higher temperatures the core does not deform but remains unpolarized up to a critical polarization. The boundaries are not sharp in this case, indicating a partially polarized shell between the core and the unpaired atoms. The temperature dependence is consistent with a tricritical point in the phase diagram.

Growth and foliar nitrogen status of four plant species exposed to atmospheric ammonia.

A chamber study was conducted to evaluate the growth response and leaf nitrogen (N) status of four plant species exposed to continuous ammonia (NH3) for 12 weeks (wk). This was intended to evaluate appropriate plant species that could be used to trap discharged NH3 from the exhaust fans in poultry feeding operations before moving off-site. Two hundred and forty bare-root plants of four species (Juniperus virginiana (red cedar), Gleditsia triacanthos var. inermis (thornless honey locust), Populus sp. (hybrid poplar), and Phalaris arundinacea (reed canary grass) were transplanted into 4- or 8-L polyethylene pots and grown in four environmentally controlled chambers. Plants placed in two of the four chambers received continuous exposure to anhydrous NH3 at 4 to 5 ppm while plants in another two chambers received no NH3. In each of the four chambers, 2 to 4 plants per species received no fertilizer while the rest of the plants were fertilized with a 100 ppm solution containing 21% N, 7% phosphorus, and 7% potassium. The results showed that honey locust was the fastest-growing species. The superior growth of honey locust among all species was also supported by its total biomass, root, and root dry matter (DM) weights. For all species there was a trend for plants exposed to NH3 to have greater leaf DM than their non-exposed counterparts at 6 (43.0 vs. 30.8%; P = 0.09) and 12 wk (47.9 vs. 36.6%; P = 0.07), and significantly greater (P

Molecular probe of pairing in the BEC-BCS crossover.

We have used optical molecular spectroscopy to probe the many-body state of paired 6Li atoms near a broad Feshbach resonance. The optical probe projects pairs of atoms onto a vibrational level of an excited molecule. The rate of excitation enables a precise measurement of the closed-channel contribution to the paired state. This contribution is found to be quite small, supporting the concept of universality for the description of broad Feshbach resonances. The dynamics of the excitation provide clear evidence for pairing across the BEC-BCS crossover and into the weakly interacting BCS regime.

Analysis of the nonlinear dynamics of daily broiler growth and feed intake.

Daily BW velocity (BWV) and acceleration (BWA) of individual birds have been demonstrated to be oscillatory. Daily feed intake velocity (FIV) and acceleration (FIA) were hypothesized to be oscillatory and to have a positive relationship with BWV and BWA, respectively. Forty-eight male broiler chicks were individually caged and provided a commercial starter feed ad libitum for 49 d. BW and feed intake (FI) were measured daily. Experiment 1 confirmed that, on a daily basis, BWV, BWA, FIV, and FIA were oscillatory. There was a positive correlation between BW and FI, BWV and FIV, and BWA and FIA. A Kohonen neural network (KNN) clustered BWV and FIV into two and three sequential phases. BWA and FIA analysis did not make definitive clusters. In experiment 2, it was hypothesized that correlation between BWV and FIV would increase with feeding of grower and finisher rations. It was hypothesized that KNN three phase clusters may provide more biologically ideal times of ration change (TORC) for starter, grower, and finisher rations. For 49 d, five treatments, nine birds per treatment, were fed starter, grower, and finisher rations singly or together with dietary changes according to an industry or KNN-determined TORC. Evaluation was made of BW, FI, and carcass characteristics. No significant mean differences were found. Compared to the industry group, the KNN group demonstrated significantly improved uniformity (i.e., smaller SD) of BW (bled out), FI, dressing percentage, and some of the carcass characteristics. Differences between KNN and industry TORC results might have been related to the length of time the birds were fed the starter, grower, and finisher diets.

Bright soliton trains of trapped Bose-Einstein condensates.

We variationally determine the dynamics of bright soliton trains composed of harmonically trapped Bose-Einstein condensates with attractive interatomic interactions. In particular, we obtain the interaction potential between two solitons. We also discuss the formation of soliton trains due to the quantum mechanical phase fluctuations of a one-dimensional condensate.