1,341 research outputs found
Quantum teleportation of EPR pair by three-particle entanglement
Teleportation of an EPR pair using triplet in state of the
Horne-Greenberger-Zeilinger form to two receivers is considered. It needs a
three-particle basis for joint measurement. By contrast the one qubit
teleportation the required basis is not maximally entangled. It consists of the
states corresponding to the maximally entanglement of two particles only. Using
outcomes of measurement both receivers can recover an unknown EPR state however
one of them can not do it separately. Teleportation of the N-particle
entanglement is discussed.Comment: 7 pages, LaTeX, 3 figure
Determining Baltic salmon foraging areas at sea using stable isotopes in scales - a tool for understanding health syndromes
Allochthonous matter : an important factor shaping the phytoplankton community in the Baltic Sea
It is well-known that nutrients shape phytoplankton communities in marine systems, but in coastal waters allochthonous dissolved organic matter (ADOM) may also be of central importance. We studied how humic substances (proxy of ADOM) and other variables influenced the nutritional strategies, size structure and pigment content of the phytoplankton community along a south-north gradient in the Baltic Sea. During the summer, the proportion of mixotrophs increased gradually from the phosphorus-rich south to the ADOM-rich north, probably due to ADOM-fueled microbes. The opposite trend was observed for autotrophs. The chlorophyll a (Chl a): carbon (C) ratio increased while the levels of photoprotective pigments decreased from south to north, indicating adaptation to the darker humic-rich water in the north. Picocyanobacteria dominated in phosphorusrich areas while nanoplankton increased in ADOM- rich areas. During the winter-spring the phytoplankton biomass and concentrations of photoprotective pigments were low, and no trends with respect to autotrophs and mixotrophs were observed. Microplankton was the dominant size group in the entire study area. We conclude that changes in the size structure of the phytoplankton community, the Chl a: C ratio and the concentrations of photoprotective pigments are indicative of changes in ADOM, a factor of particular importance in a changing climate.Peer reviewe
Diversity of larger consumers enhances interference competition effects on smaller competitors
Competition between large and small species for the same food is common in a number of ecosystems including aquatic ones. How diversity of larger consumers affects the access of smaller competitors to a limiting resource is not well understood. We tested experimentally how species richness (0–3 spp.) of benthic deposit-feeding macrofauna changes meiofaunal ostracods’ incorporation of fresh organic matter from a stable-isotope-labeled cyanobacterial bloom, using fauna from the species-poor Baltic Sea. Presence of macrofauna mostly decreased meiofaunal incorporation of bloom material, depending on the macrofauna species present. As expected, the species identity of macrofauna influenced the incorporation of organic matter by meiofauna. Interestingly, our results show that, in addition, species richness of the macrofauna significantly reduced meiofauna incorporation of freshly settled nitrogen and carbon. With more than one macrofauna species, the reduction was always greater than expected from the single-species treatments. Field data from the Baltic Sea showed a negative correlation between macrofauna diversity and meiofaunal ostracod abundance, as expected from the experimental results. We argue that this is caused by interference competition, due to spatial niche differentiation between macrofauna species reducing the sediment volume in which ostracods can feed undisturbed by larger competitors. Interference from macrofauna significantly reduces organic matter incorporation by meiofauna, indicating that diversity of larger consumers is an important factor controlling the access of smaller competitors to a limiting food resource
A multi-isotope approach to evaluate the potential of great cormorant eggs for contaminant monitoring
Contaminant monitoring in biota is important for determining environmental status and to detect or prioritize action on hazardous substances. Predators higher up a food chain are often used for monitoring of contaminants that bioaccumulate. However, it is not always possible to find higher predators that are both abundant and have a wide distribution for national or international contaminant monitoring. Great cormorants (Phalocrocorax carbo) are a widespread and increasingly common top predator of fish in fresh, brackish and salt water. We evaluate the suitability of great cormorant eggs as a matrix for contaminant monitoring by using stable isotopes of carbon, nitrogen and sulfur. Despite the fact that cormorants are migratory, egg isotope values showed a significant separation between five breeding colonies in Sweden (1 fresh water lake, 3 Baltic sites and 1 marine site). This high degree of separation indicates that eggs are primarily produced using local resources (not stored body resources) and that contaminants (mercury concentrations in this study) measured in eggs likely reflect levels in fish prey caught close to the breeding area. Compound specific stable isotope analysis was used to estimate cormorant trophic position (TP) and concentrations of mercury in eggs were positively related to TP. The results show that a multi-isotope approach, combined with good ecological diet knowledge allow for meaningful and comparative interpretation of mercury concentrations in biota and that great cormorant eggs appear a suitable matrix to measure locally derived and maternally transferred contaminants
Anti-citrullinated peptide autoantibodies, human leukocyte antigen shared epitope and risk of future rheumatoid arthritis: a nested case–control study
Introduction: The aim of this study was to characterize anti-citrullinated peptide antibody (ACPA) serostatus in pre-clinical rheumatoid arthritis (RA) with and without Human Leukocyte Antigen-Shared Epitope (HLA-SE) alleles. Methods: We identified 192 women in the Nurses’ Health Study cohorts with blood samples obtained 4 months to 17 years prior to medical record-confirmed RA diagnosis. Three controls were selected matched on age, cohort, menopausal status and post-menopausal hormone use. Reactivities to 18 ACPAs were measured using a custom BioPlex platform. We used conditional logistic regression to calculate the relative risk (RR) of RA for any ACPA-positive and peptide-specific ACPA-positive and examined RRs by time between blood draw and RA onset. Measures of multiplicative and additive interaction between any ACPA-positive and HLA-SE were calculated. Results: All ACPAs by peptide groups were significantly associated with RA risk, RRs ranged from 4.7 to 11.7. The association between ACPA and RA varied over time with the strongest association in those with blood draw less than 5 years before onset (RR 17.0 [95% CI 5.8 to 53.7]) and no association 10 or more years prior to onset (RR 1.4 [95% CI 0.5 to 4.3]). Individuals with both HLA-SE and any ACPA-positive had the highest risk of RA. HLA-SE-positive RA cases showed reactivity to more ACPA types than HLA-SE negative (χ2 test for trend, P = 0.01). Conclusions: There is increasing ACPA reactivity up to 10 years before RA onset with the strongest association within 5 years of RA onset. The magnitude of the response to ACPAs, in combination with the presence of HLA-SE, is most important for identifying those individuals with the highest risk of RA
Influence of Spin Wave Excitations on the Ferromagnetic Phase Diagram in the Hubbard-Model
The subject of the present paper is the theoretical description of collective
electronic excitations, i.e. spin waves, in the Hubbard-model. Starting with
the widely used Random-Phase-Approximation, which combines Hartree-Fock theory
with the summation of the two-particle ladder, we extend the theory to a more
sophisticated single particle approximation, namely the
Spectral-Density-Ansatz. Doing so we have to introduce a `screened`
Coulomb-interaction rather than the bare Hubbard-interaction in order to obtain
physically reasonable spinwave dispersions. The discussion following the
technical procedure shows that comparison of standard RPA with our new
approximation reduces the occurrence of a ferromagnetic phase further with
respect to the phase-diagrams delivered by the single particle theories.Comment: 8 pages, 9 figures, RevTex4, accepted for publication in Phys. Rev.
Headstrong intervention for pediatric migraine headache: a randomized clinical trial
Background
The purpose of this study was to evaluate the efficacy of a self-guided CD-ROM program (“Headstrong”) containing cognitive-behavioral self-management strategies versus an educational CD-ROM program for treating headaches, headache-related disability, and quality of life.
Methods
Participants were 35 children ages 7–12 years with migraine recruited from one university medical center and two children’s hospital headache clinics. Participants were randomly assigned to complete the Headstrong or educational control CD-ROM program over a 4-week period. Data on headache frequency, duration, and severity, migraine-related disability, and quality of life (QOL) were obtained at baseline, post-intervention, and 3-months post-intervention.
Results
At post-intervention, Headstrong resulted in lower severity (on a 10-point scale) than the control group by child report (5.06 ± 1.50 SD vs. 6.25 ± 1.92 SD, p = 0.03, ES = 0.7). At 3-months post-intervention, parents reported less migraine-related disability (on the PedMIDAS) in the Headstrong group compared to the control group (1.36 ± 2.06 SD vs. 5.18 ± 6.40 SD; p = 0.04, ES = 0.8). There were no other group differences at post treatment or at 3-months post-intervention.
Conclusions
When compared to an educational control, Headstrong resulted in lower pain severity at post-treatment and less migraine-related disability at 3-months post-intervention, by child and parent report respectively. Headache frequency and quality of life did not change more for Headstrong versus control. Additional research is needed on the Headstrong Program to increase its efficacy and to test it with a larger sample recruited from multiple centers simultaneously.The study reported in this paper was funded by a grant from the National Institutes of Health, (National Institute of Neurological Disorders and Stroke), R01-NS046641, Michael Rapoff, Principal Investigator
Comparison of the ‘Denver regimen’ against acute tuberculosis in the mouse and guinea pig
Objectives: In this study, we sought to compare the sterilizing activity of human-equivalent doses of the ‘Denver regimen ’ against acute tuberculosis (TB) infection in the standard mouse model and in the guinea pig. Methods: Pharmacokinetic studies in guinea pigs were used to establish human-equivalent doses for rifampicin, isoniazid and pyrazinamide. Guinea pigs and mice were aerosol-infected with Mycobacterium tuberculosis CDC1551 and treatment was started 2 weeks later with rifampicin/isoniazid/pyrazinamide for up to 6 months. For the first 2 weeks of therapy, the dosing frequency was 5 days/week, and for the remaining period, twice weekly. Treatment was discontinued in groups of 30 mice and 10 guinea pigs at 5 months and at 6 months, and these animals were held for a further 3 months in order to assess relapse rates. Results: Guinea pig lungs became culture-negative after 3 months of predominantly twice-weekly treatment and relapse rates were 0 % (0/10) both after 5 months and after 6 months of treatment. In contrast, all mice remained culture-positive despite 6 months of the same treatment, and 93 % (28/30) and 69 % (20/29) of mice relapsed after treatment for 5 and 6 months, respectively. Conclusions: Treatment with rifampicin/isoniazid/pyrazinamide administered at human-equivalent doses is much more potent against acute TB infection in guinea pigs than in mice. Our findings have importan
- …