1,869 research outputs found
Velocity-selective direct frequency-comb spectroscopy of atomic vapors
We present an experimental and theoretical investigation of two-photon direct
frequency-comb spectroscopy performed through velocity-selective excitation. In
particular, we explore the effect of repetition rate on the
two-photon transitions
excited in a rubidium atomic vapor cell. The transitions occur via step-wise
excitation through the states by use of the direct
output of an optical frequency comb. Experiments were performed with two
different frequency combs, one with a repetition rate of MHz and
one with a repetition rate of MHz. The experimental spectra are
compared to each other and to a theoretical model.Comment: 10 pages, 7 figure
Trisomy 19 ependymoma, a newly recognized genetico-histological association, including clear cell ependymoma
Ependymal tumors constitute a clinicopathologically heterogeneous group of brain tumors. They vary in regard to their age at first symptom, localization, morphology and prognosis. Genetic data also suggests heterogeneity. We define a newly recognized subset of ependymal tumors, the trisomy 19 ependymoma. Histologically, they are compact lesions characterized by a rich branched capillary network amongst which tumoral cells are regularly distributed. When containing clear cells they are called clear cell ependymoma. Most trisomy 19 ependymomas are supratentorial WHO grade III tumors of the young. Genetically, they are associated with trisomy 19, and frequently with a deletion of 13q21.31-31.2, three copies of 11q13.3-13.4, and/or deletions on chromosome 9. These altered chromosomal regions are indicative of genes and pathways involved in trisomy 19 ependymoma tumorigenesis. Recognition of this genetico-histological entity allows better understanding and dissection of ependymal tumors
Magnetic field induced lattice anomaly inside the superconducting state of CeCoIn: evidence of the proposed Fulde-Ferrell-Larkin-Ovchinnikov state
We report high magnetic field linear magnetostriction experiments on
CeCoIn single crystals. Two features are remarkable: (i) a sharp
discontinuity in all the crystallographic axes associated with the upper
superconducting critical field that becomes less pronounced as the
temperature increases; (ii) a distinctive second order-like feature observed
only along the c-axis in the high field (10 T ) low
temperature ( 0.35 K) region. This second order transition is
observed only when the magnetic field lies within 20 of the ab-planes and
there is no signature of it above , which raises questions regarding
its interpretation as a field induced magnetically ordered phase. Good
agreement with previous results suggests that this anomaly is related to the
transition to the Fulde-Ferrel-Larkin-Ovchinnikov superconducting state.Comment: 3 figures, 5 page
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Evaluating forecasts of the evolution of the cloudy boundary layer using diurnal composites of radar and lidar observations
Observations of boundary-layer cloud have been made using radar and lidar at Chilbolton, Hampshire, UK. These have been compared with output from 7 different global and regional models. Fifty-five cloudy days have been composited to reveal the mean diurnal variation of cloud top and base heights, cloud thickness and liquid water path of the clouds. To enable like-for-like comparison between model and observations, the observations have been averaged on to the grid of each model. The composites show a distinct diurnal cycle in observed cloud; the cloud height exhibits a sinusoidal variation throughout the day with a maximum at around 1600 and a minimum at around 0700 UTC. This diurnal cycle is captured by six of the seven models analysed, although the models generally under-predict both cloud top and cloud base heights throughout the day. The two worst performing models in terms of cloud boundaries also have biases of around a factor of two in liquid water path; these were the only two models that did not include an explicit formulation for cloud-top entrainment
An Experimental and Semi-Empirical Method to Determine the Pauli-Limiting Field in Quasi 2D Superconductors as applied to -(BEDT-TTF)Cu(NCS): Strong Evidence of a FFLO State
We present upper critical field data for -(BEDT-TTF)Cu(NCS)
with the magnetic field close to parallel and parallel to the conducting
layers. We show that we can eliminate the effect of vortex dynamics in these
layered materials if the layers are oriented within 0.3 degrees of parallel to
the applied magnetic field. Eliminating vortex effects leaves one remaining
feature in the data that corresponds to the Pauli paramagnetic limit ().
We propose a semi-empirical method to calculate the in quasi 2D
superconductors. This method takes into account the energy gap of each of the
quasi 2D superconductors, which is calculated from specific heat data, and the
influence of many body effects. The calculated Pauli paramagnetic limits are
then compared to critical field data for the title compound and other organic
conductors. Many of the examined quasi 2D superconductors, including the above
organic superconductors and CeCoIn, exhibit upper critical fields that
exceed their calculated suggesting unconventional superconductivity. We
show that the high field low temperature state in
-(BEDT-TTF)Cu(NCS) is consistent with the Fulde Ferrell Larkin
Ovchinnikov state.Comment: 8 pages, 9 figures, 10 years of dat
The important role for intravenous iron in perioperative patient blood management in major abdominal surgery: a randomized controlled trial
Objective: To determine if preoperative intravenous (IV) iron improves outcomes in abdominal surgery patients. Summary Background Data: Preoperative iron deficiency anemia (IDA) occurs frequently; however if left untreated, increases the risk of blood transfusion allogeneic blood transfusion (ABT). Limited evidence supports IDA treatment with preoperative IV iron. This randomized controlled trial aimed to determine whether perioperative IV iron reduced the need for ABT. Methods: Between August 2011 and November 2014, 72 patients with IDA were assigned to receive either IV iron or usual care. The primary endpoint was incidence of ABT. Secondary endpoints were various hemoglobin (Hb) levels, change in Hb between time points, length of stay, iron status, morbidity, mortality, and quality of life 4 weeks postsurgery. Results: A 60% reduction in ABT was observed in the IV iron group compared with the usual care group (31.25% vs 12.5%). Hb values, although similar at randomization, improved by 0.8 g/dL with IV iron compared with 0.1 g/dL with usual care (P = 0.01) by the day of admission. The IV iron group had higher Hb 4 weeks after discharge compared with the usual care group (1.9 vs 0.9 g/dL, P = 0.01), and a shorter length of stay (7.0 vs 9.7 d, P = 0.026). There was no difference in discharge Hb levels, morbidity, mortality, or quality of life. Conclusions: Administration of perioperative IV iron reduces the need for blood transfusion, and is associated with a shorter hospital stay, enhanced restoration of iron stores, and a higher mean Hb concentration 4 weeks after surgery.Bernd Froessler, Peter Palm, Ingo Weber, Nicolette A. Hodyl, Rajvinder Singh and Elizabeth M. Murph
Network information and connected correlations
Entropy and information provide natural measures of correlation among
elements in a network. We construct here the information theoretic analog of
connected correlation functions: irreducible --point correlation is measured
by a decrease in entropy for the joint distribution of variables relative
to the maximum entropy allowed by all the observed variable
distributions. We calculate the ``connected information'' terms for several
examples, and show that it also enables the decomposition of the information
that is carried by a population of elements about an outside source.Comment: 4 pages, 3 figure
Assessment of efficacy and safety of the herbal medicinal product BNO 1016 in chronic rhinosinusitis
Background: The objective of this clinical trial (CRS-02) was to assess the efficacy, safety and tolerability of two dosages of the herbal medicinal product BNO 1016 (Sinupret extract) in patients with chronic rhinosinusitis (CRS).
Methodology: 929 patients suffering from CRS were enrolled in this randomised placebo-controlled trial with a treatment period of 12 weeks. The primary endpoint was the mean Major Symptom Score (MSS) in week 8 and week 12 compared to placebo. Secondary endpoints included further MSS related parameters and responder rates over time. Pharmacoeconomic endpoints were also analysed. Finally, safety and tolerability were evaluated.
Results: Sinupret extract was not superior over placebo regarding the primary endpoint. However, the results of the secondary endpoints showed a clear trend towards superior efficacy. Therefore, additional post-hoc sensitivity analyses were performed in patients with a baseline MSS > 9 and persistence of disease > 1 year diagnosed by specialists in otorhinolaryngology.Those patients significantly benefited from Sinupret extract. Therapy was superior for the primary endpoint analysis. Patients were less impaired with respect to work and daily activities. A good safety and tolerability of Sinupret extract was assured in all patients.
Conclusions: Sinupret extract can safely be administered in patients with CRS. Although the primary endpoint of the study was not significant, a post-hoc subgroup analysis in patients whose disease was diagnosed by a specialist revealed a pronounced treatment effect. Effects in that subgroup were even stronger with longer disease persistence and stronger severity
Pressure Evolution of a Field Induced Fermi Surface Reconstruction and of the Neel Critical Field in CeIn3
We report high-pressure skin depth measurements on the heavy fermion material
CeIn3 in magnetic fields up to 64 T using a self-resonant tank circuit based on
a tunnel diode oscillator. At ambient pressure, an anomaly in the skin depth is
seen at 45 T. The field where this anomaly occurs decreases with applied
pressure until approximately 1.0 GPa, where it begins to increase before
merging with the antiferromagnetic phase boundary. Possible origins for this
transport anomaly are explored in terms of a Fermi surface reconstruction. The
critical magnetic field at which the Neel ordered phase is suppressed is also
mapped as a function of pressure and extrapolates to the previous ambient
pressure measurements at high magnetic fields and high pressure measurements at
zero magnetic field.Comment: 15 pages, 5 figure
Towards understanding the variability in biospheric CO2 fluxes:Using FTIR spectrometry and a chemical transport model to investigate the sources and sinks of carbonyl sulfide and its link to CO2
Understanding carbon dioxide (CO2) biospheric processes is of great importance because the terrestrial exchange drives the seasonal and interannual variability of CO2 in the atmosphere. Atmospheric inversions based on CO2 concentration measurements alone can only determine net biosphere fluxes, but not differentiate between photosynthesis (uptake) and respiration (production). Carbonyl sulfide (OCS) could provide an important additional constraint: it is also taken up by plants during photosynthesis but not emitted during respiration, and therefore is a potential means to differentiate between these processes. Solar absorption Fourier Transform InfraRed (FTIR) spectrometry allows for the retrievals of the atmospheric concentrations of both CO2 and OCS from measured solar absorption spectra. Here, we investigate co-located and quasi-simultaneous FTIR measurements of OCS and CO2 performed at five selected sites located in the Northern Hemisphere. These measurements are compared to simulations of OCS and CO2 using a chemical transport model (GEOS-Chem). The coupled biospheric fluxes of OCS and CO2 from the simple biosphere model (SiB) are used in the study. The CO2 simulation with SiB fluxes agrees with the measurements well, while the OCS simulation reproduced a weaker drawdown than FTIR measurements at selected sites, and a smaller latitudinal gradient in the Northern Hemisphere during growing season when comparing with HIPPO (HIAPER Pole-to-Pole Observations) data spanning both hemispheres. An offset in the timing of the seasonal cycle minimum between SiB simulation and measurements is also seen. Using OCS as a photosynthesis proxy can help to understand how the biospheric processes are reproduced in models and to further understand the carbon cycle in the real world
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