Integral correlation measures for multiparticle physics

We report on a considerable improvement in the technique of measuring multiparticle correlations via integrals over correlation functions. A modification of measures used in the characterization of chaotic dynamical sytems permits fast and flexible calculation of factorial moments and cumulants as well as their differential versions. Higher order correlation integral measurements even of large multiplicity events such as encountered in heavy ion collisons are now feasible. The change from ``ordinary'' to ``factorial'' powers may have important consequences in other fields such as the study of galaxy correlations and Bose-Einstein interferometry.Comment: 23 pages, 6 tar-compressed uuencoded PostScript figures appended, preprint TPR-92-4

Early onset preeclampsia is characterized by altered placental lipid metabolism and a premature increase in circulating FABP4

Preeclampsia is a pregnancy-associated disorder that manifests as a sudden increase in maternal blood pressure accompanied by proteinuria. Because the placenta is a key organ in preeclampsia, we used proteomic and lipidomic analyses to compare placentae from preeclamptic and gestational age matched control pregnancies. Fatty acid binding protein 4 (FABP4), enoyl-CoA dehydrogenase and delta-3,5-delta-2,4-dienoyl-CoA isomerase had altered abundance in preeclamptic placentae compared to controls. FABP4 placental protein and RNA and plasma levels were all increased in early-onset preeclampsia (prior to 28 weeks gestation) compared to controls (6-fold, 3.3-fold and 3.5-fold respectively). After 28 weeks, FABP4 protein in control placenta and plasma increased to the same concentrations as in preeclampsia. Total tetracosapentaenoic acid in preeclamptic placentae was decreased to 0.6 of control levels before 28 weeks. The data indicate a disruption of fatty acid transport and metabolism in the placenta in early onset preeclampsia that is reflected in the maternal plasma

The work undertaken by mechanically ventilated patients in intensive care : a qualitative meta-ethnography of survivors' experiences

Background: Mechanical ventilation is a routine intervention for the critically ill but patients' experiences of this intervention are largely hidden from clinicians. A comprehensive understanding of Intensive Care Units survivors' accounts is required to provide health professionals with evidence about the patients' experience to deliver patient-centred care. Objectives: To synthesise qualitative findings from international studies to understand Intensive Care Unit survivors' experiences of mechanical ventilation, clarify the components of patient-centred care from the patient perspective and understand what can be done by health professionals to improve care processes. Design: A meta-ethnography of qualitative evidence following ENTREQ recommendations for reporting systematic reviews. Data Sources: Eight databases (MEDLINE, AMED, CINAHL, PsychINFO, Scopus, WileyOnline, PubMed Central, TRIP) were systematically searched using a piloted strategy described in a published protocol. Searches were completed on 31.8.16 and no date restrictions were placed. Searches were updated on 25.4.17. Review Methods: Two researchers independently reviewed studies against pre-determined inclusion criteria to assess their eligibility. Studies were included if they reported on the adult patient experience of mechanical ventilation and used qualitative data collection and analysis methods. All included studies were quality appraised. Participant quotes and concepts, described within the categories and themes of published studies, were extracted by one reviewer and coded by two reviewers. A process of constant comparison, which is central to meta-ethnography, facilitated the re-interpretation of data by a team of researchers to generate the final qualitative synthesis. The Enhancing Transparency in Reporting the Synthesis of Qualitative (ENTREQ) statement was used to ensure that all synthesis stages were comprehensively reported. Results: Findings from 38 studies, with 608 participants, informed a patient-centred trajectory model; three overlapping stages; alienation, hidden work and recovery characterised the experiences of mechanical ventilation survivors. Health professionals could positively influence the patient experience by promoting ‘trust’ and being vigilant so that patients felt ‘safe’. Care provision that promoted ‘personalisation’ helped participants to retain their identity as unique human beings. Conclusions: For the first time the pooling of qualitative findings from international studies, using meta-ethnography, has provided a patient-centred model of mechanical ventilation survivors’ experiences of their care processes. Patients may actively engage or passively endure the treatment burden associated with mechanical ventilation. Keywords: Critical care; mechanical ventilation; patient experience; qualitative synthesis, care processes, meta-ethnograph

Soft-core meson-baryon interactions. II. πN\pi N and K+NK^+ N scattering

The $\pi N$ potential includes the t-channel exchanges of the scalar-mesons $\sigma$ and f_0, vector-meson $\rho$, tensor-mesons f_2 and f_2' and the Pomeron as well as the s- and u-channel exchanges of the nucleon N and the resonances $\Delta$, Roper and S_{11}. These resonances are not generated dynamically. We consider them as, at least partially, genuine three-quark states and we treat them in the same way as the nucleon. The latter two resonances were needed to find the proper behavior of the phase shifts at higher energies in the corresponding partial waves. The soft-core $\pi N$-model gives an excellent fit to the empirical $\pi N$ S- and P-wave phase shifts up to T_{lab}=600 MeV. Also the scattering lengths have been reproduced well and the soft-pion theorems for low-energy $\pi N$ scattering are satisfied. The soft-core model for the $K^+ N$ interaction is an SU_f(3)-extension of the soft-core $\pi N$-model. The $K^+ N$ potential includes the t-channel exchanges of the scalar-mesons a_0, $\sigma$ and f_0, vector-mesons $\rho$, $\omega$ and $\phi$, tensor-mesons a_2, f_2 and f_2' and the Pomeron as well as u-channel exchanges of the hyperons $\Lambda$ and $\Sigma$. The fit to the empirical $K^+ N$ S-, P- and D-wave phase shifts up to T_{lab}=600 MeV is reasonable and certainly reflects the present state of the art. Since the various $K^+ N$ phase shift analyses are not very consistent, also scattering observables are compared with the soft-core $K^+ N$-model. A good agreement for the total and differential cross sections as well as the polarizations is found.Comment: 24 pages, 20 PostScript figures, revtex4, submitted to Phys. Rev.

Factorial Moments in a Generalized Lattice Gas Model

We construct a simple multicomponent lattice gas model in one dimension in which each site can either be empty or occupied by at most one particle of any one of $D$ species. Particles interact with a nearest neighbor interaction which depends on the species involved. This model is capable of reproducing the relations between factorial moments observed in high--energy scattering experiments for moderate values of $D$. The factorial moments of the negative binomial distribution can be obtained exactly in the limit as $D$ becomes large, and two suitable prescriptions involving randomly drawn nearest neighbor interactions are given. These results indicate the need for considerable care in any attempt to extract information regarding possible critical phenomena from empirical factorial moments.Comment: 15 pages + 1 figure (appended as postscript file), REVTEX 3.0, NORDITA preprint 93/4

Testing the sediment-trapping paradigm of seagrass: Do seagrasses influence nutrient status and sediment structure in tropical intertidal environments?

Seagrass meadows are considered important for sediment trapping and sediment stabilisation. Deposition of fine sediments and associated adsorbed nutrients is considered an important part of the chemical and biological processes attributed to seagrass communities. This paradigm was based on work in temperate regions on Zostera marina and in tropical regions on Thalassia testudinum, two species that maintain relatively high biomass, stable meadows. The current study investigates this concept for three species of intertidal tropical seagrass meadows in northeastern Australia. Sediment structure and nutrient status did not differ between vegetated and unvegated habitats in intertidal areas within the central region of the Great Barrier Reef World Heritage Area. The 'trapping' functions that have been attributed to seagrasses need to be re-assessed for a variety of locations and species before they can be accepted as dogma. In tropical Australia, intertidal meadows are predominantly ephemeral and comprised of structurally small species of low biomass. Consequently, sediment trapping within these meadows is largely insignificant

Timing of the first vancomycin maintenance dose in an acute hospital setting - room for improvement?

Introduction Intravenous vancomycin therapy typically starts with a loading dose followed by a maintenance dose 12 to 24 hours later. In the acute hospital setting, this often results in doses being administered in the middle of the night, which is impractical for both patients and staff. This audit examined current practice and developed new guidelines to support greater flexibility in the timing of the first maintenance dose. Methods Data recording forms used by pharmacists to support the therapeutic drug monitoring of vancomycin were collected from two hospital sites over six weeks. Forms containing at least two vancomycin concentrations were selected and the time of administration of the first maintenance dose was recorded. Individual vancomycin pharmacokinetic parameter estimates were obtained using MAP Bayesian analysis then used to predict vancomycin concentrations 6, 8, 10, 12 and 14 hours after a banded loading dose and 20 mg/kg (capped at 3000 mg). Predicted concentrations were compared with a target range of 10 – 20 mg/L. Results Data were obtained from 49 patients with a mean (SD) age of 63.1 (16.7) years and weight 80.1 (27.6) kg. In all patients, creatinine clearance estimates were >40 mL/min and, according to current practice guidelines, all patients required 12 hourly maintenance dosing. The time recorded for the administration of the first maintenance dose was between 11 pm and 7 am in 30 (61%) of these patients. In 14 patients (29%), the first maintenance dose was administered >12 hours after loading. The target range was achieved with banded doses (20 mg/kg) in 65% (71%) of concentrations at 6 hours, 74% (84%) at 8 hours, 57% (67%) at 10 hours, 53% (55%) at 12 hours and 39% (43%) at 14 hours. Conclusions This audit has shown that current practice results in a high proportion of vancomycin maintenance doses being administered at impractical times. Allowing a more flexible time window of 6-12 hours after the loading dose for administration of the first vancomycin maintenance dose could help to alleviate this problem and reduce the risk of early subtherapeutic vancomycin trough concentrations

An extreme ultraviolet spectrometer experiment for the Shuttle Get Away Special Program

An extreme ultraviolet (EUV) spectrometer experiment operated successfully during the STS-7 mission in an experiment to measure the global and diurnal variation of the EUV airglow. The spectrometer is an F 3.5 Wadsworth mount with mechanical collimator, a 75 x 75 mm grating, and a bare microchannel plate detector providing a spectral resolution of 7 X FWHM. Read-out of the signal is through discrete channels or resistive anode techniques. The experiment includes a microcomputer, 20 Mbit tape recorder, and a 28V, 40 Ahr silver-zinc battery. It is the first GAS payload to use an opening door. The spectrometer's 0.1 x 4.2 deg field of view is pointed vertically out of the shuttle bay. During the STS-7 flight data were acquired continuously for a period of 5 hours and 37 minutes, providing spectra of the 570 A to 850 A wavelength region of the airglow. Five diurnal cycles of the 584 A emission of neutral helium and the 834 A emission of ionized atomic oxygen were recorded. The experiment also recorded ion events and pressure pulses associated with thruster firings. The experiment is to fly again on Mission 41-F

The [4+2]‐Cycloaddition of α‐Nitrosoalkenes with Thiochalcones as a Prototype of Periselective Hetero‐Diels–Alder Reactions—Experimental and Computational Studies

The [4+2]‐cycloadditions of α‐nitrosoalkenes with thiochalcones occur with high selectivity at the thioketone moiety of the dienophile providing styryl‐substituted 4H‐1,5,2‐oxathiazines in moderate to good yields. Of the eight conceivable hetero‐Diels–Alder adducts only this isomer was observed, thus a prototype of a highly periselective and regioselective cycloaddition has been identified. Analysis of crude product mixtures revealed that the α‐nitrosoalkene also adds competitively to the thioketone moiety of the thiochalcone dimer affording bis‐heterocyclic [4+2]‐cycloadducts. The experiments are supported by high‐level DFT calculations that were also extended to related hetero‐Diels–Alder reactions of other nitroso compounds and thioketones. These calculations reveal that the title cycloadditions are kinetically controlled processes confirming the role of thioketones as superdienophiles. The computational study was also applied to the experimentally studied thiochalcone dimerization, and showed that the 1,2‐dithiin and 2H‐thiopyran isomers are in equilibrium with the monomer. Again, the DFT calculations indicate kinetic control of this process