2,286 research outputs found
NMR Simulation of an Eight-State Quantum System
The propagation of excitation along a one-dimensional chain of atoms is
simulated by means of NMR. The physical system used as an analog quantum
computer is a nucleus of 133-Cs (spin 7/2) in a liquid crystalline matrix. The
Hamiltonian of migration is simulated by using a special 7-frequency pulse, and
the dynamics is monitored by following the transfer of population from one of
the 8 spin energy levels to the other.Comment: 10 pages, 3 figure
Effect of wheat distillers dried grains with solubles or sugar beet pulp on prevalence of Salmonella enterica Typhimurium in weaned pigs
Salmonella enterica Typhimurium (ST) is of concern in the swine industry with
relevance for animal health and consumer safety. Nutritional strategies might
help to reduce ST infection and transmission. This study examined the
potential of wheat (Triticum aestivum) distillers dried grains with solubles
(DDGS) and sugar beet (Beta vulgaris) pulp (SBP) to alter intestinal microbial
communities and ST shedding using a Trojan model. Weaned pigs (n = 105; 28.5 ±
3.5 d of age) were separated into 3 treatment groups (7 pigs/pen) and fed a
wheat-based control diet or the control diet formulated with 15% wheat DDGS or
6% SBP inclusion. Following 12 d of diet adaptation, 2 pigs/pen were
inoculated with 2 x 109 cfu ST, resistant to novobiocin and nalidixic acid.
Fecal swabs were taken from infected pigs and pen-mates (contact pigs) for 9 d
following challenge, enriched in nutrient broth for 24 h, and plated on
selective media to determine prevalence of ST. The ranges of prevalence of ST
in feces were from 90 to 100% in challenged pigs and 74 to 78% in contact
pigs. No influence of treatment on rectal temperature and prevalence of ST in
contact pigs were observed. Fifteen contact pigs were euthanized per treatment
group on 9 and 10 d postchallenge to enumerate in intestinal contents (ileum,
cecum, and proximal colon), Lactobacillus spp., Enterobacteriaceae, and
Clostridium clusters I, VI, and XVIa by quantitative PCR (qPCR) and to
determine ST prevalence by selective culture. No significant effects of diet
were observed with respect to ST prevalence in feces, ileum, cecum, colon, and
lymph nodes of contact pigs. Compared with the control diet, DGGS and SBP
diets showed a trend towards increased (P < 0.1) number of Lactobacillus
species in the cecum and colon. Although both wheat DGGS and SBP tended to
increase the Lactobacillus spp. neither of the feed ingredients affected ST
prevalence
Experimental realization of a continuous version of the Grover algorithm
A continuous, analog version of the Grover algorithm is realized using NMR.
The system studied is 23Na in a liquid crystal medium. The presence of
quadrupolar coupling makes the spin I=3/2 nucleus a 2-qubit system. Applying a
specially designed pulse sequence, the time evolution of the spin density
operator is described in an interaction representation which has no external
time-dependent radio-frequency fields. This approach is used to implement one
instance of the continuous Grover search for the transform of a uniform state
to a target state, and the implementation provides a clear physical
interpretation of the algorithm. The experimental results are in good agreement
with the theory.Comment: 14 pages plus 2 figures, accepted for publication in Phys. Rev.
Simultaneous Anaerobic and Aerobic Ammonia and Methane Oxidation under Oxygen Limitation Conditions
Methane and ammonia have to be removed from wastewater treatment effluent in order to discharge it to receiving water bodies. A potential solution for this is a combination of simultaneous ammonia and methane oxidation by anaerobic ammonia oxidation (anammox) bacteria and nitrite/nitrate-dependent anaerobic methane oxidation (N-damo) microorganisms. When applied, these microorganisms will be exposed to oxygen, but little is known about the effect of a low concentration of oxygen on a culture containing these microorganisms. In this study, a stable coculture containing anammox and N-damo microorganisms in a laboratory scale bioreactor was established under oxygen limitation. Membrane inlet mass spectrometry (MIMS) was used to directly measure the in situ simultaneous activity of N-damo, anammox, and aerobic ammonia-oxidizing microorganisms. In addition, batch tests revealed that the bioreactor also harbored aerobic methanotrophs and anaerobic methanogens. Together with fluorescence in situ hybridization (FISH) analysis and metagenomics, these results indicate that the combination of N-damo and anammox activity under the continuous supply of limiting oxygen concentrations is feasible and can be implemented for the removal of methane and ammonia from anaerobic digester effluents. IMPORTANCE Nitrogen in wastewater leads to eutrophication of the receiving water bodies, and methane is a potent greenhouse gas; it is therefore important that these are removed from wastewater. A potential solution for the simultaneous removal of nitrogenous compounds and methane is the application of a combination of nitrite/ nitrate-dependent methane oxidation (N-damo) and anaerobic ammonia oxidation (annamox). In order to do so, it is important to investigate the effect of oxygen on these two anaerobic processes. In this study, we investigate the effect of a continuous oxygen supply on the activity of an anaerobic methane- and ammonia-oxidizing coculture. The findings presented in this study are important for the potential application of these two microbial processes in wastewater treatment
Lifetime prevalence of novel psychoactive substances use among adults in the USA: Sociodemographic, mental health and illicit drug use correlates. Evidence from a population-based survey 2007–2014
INTRODUCTION: As Novel psychoactive substances (NPS) are conceived to mimic the effects of common illicit drugs, they represent a serious public health challenge due to the spike in intoxications and fatalities that have been linked to their use. This study aims to provide epidemiological data on NPS use in the USA, determining lifetime prevalence of use and defining demographic, socioeconomic, drug use patterns and mental health correlates. METHODS: This study uses secondary data from the US National Survey on Drug Use and Health (NSDUH), which is a large cross-sectional population-based survey carried out annually in the USA. We analysed data from 2007-14 (N = 307,935) using bivariate descriptive analysis and binary logistic regression to calculate prevalence and determine factors underlying NPS consumption. Adjusted odds ratios (OR) with 95% CI's were calculated for a set of selected independent variables. RESULTS AND DISCUSSION: Our analysis NSDUH from 2007-14 highlights an increase in NPS use among adults, especially among white young men aged 18 to 25. Although the level of education of NPS users was relatively higher as compared to non-users, NPS users seemed to have a less wealthy situation. However, socioeconomic vulnerability appeared to be less important than mental health issues as a correlate to NPS use. NPS users seem to have followed a pattern of polysubstance use throughout their life, which involves both traditional illicit drugs and classic synthetic drugs. As NPS use seemed to be more prevalent among people having mental health issues, the rise in their use may have a negative impact on population mental health outcomes. CONCLUSION: Further comparative research on trends in NPS use and potential public health responses would be instrumental for developing appropriate health interventions, including drug checking, education for users and training for healthcare professionals working both within emergency wards and in/outpatient addiction and mental health services
Quantum Extremism: Effective Potential and Extremal Paths
The reality and convexity of the effective potential in quantum field
theories has been studied extensively in the context of Euclidean space-time.
It has been shown that canonical and path-integral approaches may yield
different results, thus resolving the `convexity problem'. We discuss the
transferral of these treatments to Minkowskian space-time, which also
necessitates a careful discussion of precisely which field configurations give
the dominant contributions to the path integral. In particular, we study the
effective potential for the N=1 linear sigma model.Comment: 11 pages, 4 figure
An analysis of major target deviations in craniospinal irradiation treatment plans for patients with intermediate-risk medulloblastoma within a phase 3 clinical trial (Children\u27s Oncology Group Study ACNS0331)
PURPOSE: Craniospinal irradiation remains an essential and yet difficult part of the treatment of patients with medulloblastoma. Whereas technological advances offer promise of increased conformity, realiance on advanced technology is not without risk, and it remains critical to carefully delineate targets. We describe examples of target deviations (TDs) in craniospinal irradiation treatment plans for postoperative patients with medulloblastoma in a phase 3 clinical trial (ACNS 0331).
METHODS AND MATERIALS: The principal investigator independently performed a review of the treatment plans and portal films of enrolled patients and evaluated the plans for TDs. TDs of dose, dose uniformity, and volume were defined as major or minor deviations. Major TDs scored as protocol violations. The effect of major TDs on event-free survival (EFS) and overall survival (OS) was evaluated using the stratified Cox proportional hazards model.
RESULTS: Of the 549 patients enrolled, 461 were available for this analysis. Thirty-two (7%) plans did not have data sufficient for TD evaluation. Major TDs were found in 32 of the 461 plans (7%). Of those, 21 were deviations of target volume alone, 7 were deviations of target dose alone, and 4 were deviations of both target volume and dose. The 25 patients with TDs of volume involved 29 sites. The most common major TDs of volume involved the brain (9 of 29) and the posterior fossa (9 of 29). On Cox proportional hazards modeling, the presence of a major TD did not statistically significantly affect EFS (hazard ratio, 0.98; 95% confidence interval, 0.45-2.11;
CONCLUSIONS: Although intensity modulated radiation therapy and proton therapy are promising in improving conformity and sparing organs at risk, technology does not substitute for careful anatomic definition of target volumes. The study was not powered to evaluate the effect of TDs on EFS and OS; therefore, the statistical analysis presented in this study must be interpreted with caution
Global nitrogen budgets in cereals: A 50-year assessment for maize, rice, and wheat production systems
Industrially produced N-fertilizer is essential to the production of cereals that supports current and projected human populations. We constructed a top-down global N budget for maize, rice, and wheat for a 50-year period (1961 to 2010). Cereals harvested a total of 1551 Tg of N, of which 48% was supplied through fertilizer-N and 4% came from net soil depletion. An estimated 48% (737 Tg) of crop N, equal to 29, 38, and 25 kg ha−1 yr−1 for maize, rice, and wheat, respectively, is contributed by sources other than fertilizer- or soil-N. Non-symbiotic N2 fixation appears to be the major source of this N, which is 370 Tg or 24% of total N in the crop, corresponding to 13, 22, and 13 kg ha−1 yr−1 for maize, rice, and wheat, respectively. Manure (217 Tg or 14%) and atmospheric deposition (96 Tg or 6%) are the other sources of N. Crop residues and seed contribute marginally. Our scaling-down approach to estimate the contribution of non-symbiotic N2 fixation is robust because it focuses on global quantities of N in sources and sinks that are easier to estimate, in contrast to estimating N losses per se, because losses are highly soil-, climate-, and crop-specific
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