Kinetics of four-wave mixing for a 2D magneto-plasma in strong magnetic fields

We investigate the femtosecond kinetics of an optically excited 2D magneto-plasma at intermediate and high densities under a strong magnetic field perpendicular to the quantum well (QW). We assume an additional weak lateral confinement which lifts the degeneracy of the Landau levels partially. We calculate the femtosecond dephasing and relaxation kinetics of the laser pulse excited magneto-plasma due to bare Coulomb potential scattering, because screening is under these conditions of minor importance. In particular the time-resolved and time-integrated four-wave mixing (FWM) signals are calculated by taking into account three Landau subbands in both the valance and the conduction band assuming an electron-hole symmetry. The FWM signals exhibit quantum beats mainly with twice the cyclotron frequency. Contrary to general expectations, we find no pronounced slowing down of the dephasing with increasing magnetic field. On the contrary, one obtains a decreasing dephasing time because of the increase of the Coulomb matrix elements and the number of states in a given Landau subband. In the situation when the loss of scattering channels exceeds these increasing effects, one gets a slight increase at the dephasing time. However, details of the strongly modulated scattering kinetics depend sensitively on the detuning, the plasma density, and the spectral pulse width relative to the cyclotron frequency.Comment: 13 pages, in RevTex format, 10 figures, Phys. Rev B in pres

Trajectories in New York Heart Association functional class in heart failure across the ejection fraction spectrum: data from the Swedish Heart Failure Registry.

AIMS: To investigate incidence, predictors and prognostic implications of longitudinal New York Heart Association (NYHA) class changes (i.e. improving or worsening vs. stable NYHA class) in heart failure (HF) across the ejection fraction (EF) spectrum. METHODS AND RESULTS: From the Swedish HF Registry, 13 535 patients with EF and ≥2 NYHA class assessments were considered. Multivariable multinomial regressions were fitted to identify the independent predictors of NYHA change. Over a 1-year follow-up, 69% of patients had stable, 17% improved, and 14% worsened NYHA class. Follow-up in specialty care predicted improving NYHA class, whereas an in-hospital patient registration, lower EF, renal disease, lower mean arterial pressure, older age, and longer HF duration predicted worsening. The association between NYHA change and subsequent outcomes was assessed with multivariable Cox models. When adjusting for the NYHA class at baseline, improving NYHA class was independently associated with lower while worsening with higher risk of all-cause and cardiovascular mortality, and first HF hospitalization. After adjustment for the NYHA class at follow-up, NYHA class change did not predict morbidity/mortality. NYHA class assessment at baseline and follow-up predicted morbidity/mortality on top of the changes. Results were consistent across the EF spectrum. CONCLUSION: In a large real-world HF population, NYHA class trajectories predicted morbidity/mortality after extensive adjustments. However, the prognostic role was entirely explained by the resulting NYHA class, i.e. the follow-up value. Our results highlight that considering one-time NYHA class assessment, rather than trajectories, might be the preferable approach in clinical practice and for clinical trial design

Ultrafast Coulomb-induced dynamics of 2D magnetoexcitons

We study theoretically the ultrafast nonlinear optical response of quantum well excitons in a perpendicular magnetic field. We show that for magnetoexcitons confined to the lowest Landau levels, the third-order four-wave-mixing (FWM) polarization is dominated by the exciton-exciton interaction effects. For repulsive interactions, we identify two regimes in the time-evolution of the optical polarization characterized by exponential and {\em power law} decay of the FWM signal. We describe these regimes by deriving an analytical solution for the memory kernel of the two-exciton wave-function in strong magnetic field. For strong exciton-exciton interactions, the decay of the FWM signal is governed by an antibound resonance with an interaction-dependent decay rate. For weak interactions, the continuum of exciton-exciton scattering states leads to a long tail of the time-integrated FWM signal for negative time delays, which is described by the product of a power law and a logarithmic factor. By combining this analytic solution with numerical calculations, we study the crossover between the exponential and non-exponential regimes as a function of magnetic field. For attractive exciton-exciton interaction, we show that the time-evolution of the FWM signal is dominated by the biexcitonic effects.Comment: 41 pages with 11 fig

Patient profile and outcomes associated with follow-up in specialty vs. primary care in heart failure.

AIMS: Factors influencing follow-up referral decisions and their prognostic implications are poorly investigated in patients with heart failure (HF) with reduced (HFrEF), mildly reduced (HFmrEF), and preserved (HFpEF) ejection fraction (EF). We assessed (i) the proportion of, (ii) independent predictors of, and (iii) outcomes associated with follow-up in specialty vs. primary care across the EF spectrum. METHODS AND RESULTS: We analysed 75 518 patients from the large and nationwide Swedish HF registry between 2000-2018. Multivariable logistic regression models were fitted to identify the independent predictors of planned follow-up in specialty vs. primary care, and multivariable Cox models to assess the association between follow-up type and outcomes. In this nationwide registry, 48 115 (64%) patients were planned for follow-up in specialty and 27 403 (36%) in primary care. The median age was 76 [interquartile range (IQR) 67-83] years and 27 546 (36.5%) patients were female. Key independent predictors of planned follow-up in specialty care included optimized HF care, that is follow-up in a nurse-led HF clinic [odds ratio (OR) 4.60, 95% confidence interval (95% CI) 4.41-4.79], use of HF devices (OR 3.99, 95% CI 3.62-4.40), beta-blockers (OR 1.39, 95% CI 1.32-1.47), renin-angiotensin system/angiotensin-receptor-neprilysin inhibitors (OR 1.21, 95% CI 1.15-1.27), and mineralocorticoid receptor antagonists (OR 1.31, 95% CI 1.26-1.37); and more severe HF, that is higher NT-proBNP (OR 1.13, 95% CI 1.06-1.20) and NYHA class (OR 1.13, 95% CI 1.08-1.19). Factors associated with lower likelihood of follow-up in specialty care included older age (OR 0.29, 95% CI 0.28-0.30), female sex (OR 0.89, 95% CI 0.86-0.93), lower income (OR 0.79, 95% CI 0.76-0.82) and educational level (OR 0.77, 95% CI 0.73-0.81), higher EF [HFmrEF (OR 0.65, 95% CI 0.62-0.68) and HFpEF (OR 0.56, 95% CI 0.53-0.58) vs. HFrEF], and higher comorbidity burden, such as presence of kidney disease (OR 0.91, 95% CI 0.87-0.95), atrial fibrillation (OR 0.85, 95% CI 0.81-0.89), and diabetes mellitus (OR 0.92, 95% CI 0.88-0.96). A planned follow-up in specialty care was independently associated with lower risk of all-cause [hazard ratio (HR) 0.78, 95% CI 0.76-0.80] and cardiovascular death (HR 0.76, 95% CI 0.73-0.78) across the EF spectrum, but not of HF hospitalization (HR 1.06, 95% CI 1.03-1.10). CONCLUSIONS: In a large nationwide HF population, referral to specialty care was linked with male sex, younger age, lower EF, lower comorbidity burden, better socioeconomic environment and optimized HF care, and associated with better survival across the EF spectrum. Our findings highlight the need for greater and more equal access to HF specialty care and improved quality of primary care

The Role of Nonequilibrium Dynamical Screening in Carrier Thermalization

We investigate the role played by nonequilibrium dynamical screening in the thermalization of carriers in a simplified two-component two-band model of a semiconductor. The main feature of our approach is the theoretically sound treatment of collisions. We abandon Fermi's Golden rule in favor of a nonequilibrium field theoretic formalism as the former is applicable only in the long-time regime. We also introduce the concept of nonequilibrium dynamical screening. The dephasing of excitonic quantum beats as a result of carrier-carrier scattering is brought out. At low densities it is found that the dephasing times due to carrier-carrier scattering is in picoseconds and not femtoseconds, in agreement with experiments. The polarization dephasing rates are computed as a function of the excited carrier density and it is found that the dephasing rate for carrier-carrier scattering is proportional to the carrier density at ultralow densities. The scaling relation is sublinear at higher densities, which enables a comparison with experiment.Comment: Revised version with additional refs. 12 pages, figs. available upon request; Submitted to Phys. Rev.

Effects of Three Months of Low Molecular Weight Heparin (dalteparin) Treatment After Bypass Surgery for Lower Limb Ischemia—A Randomised Placebo-controlled Double Blind Multicentre Trial

AbstractObjectivesTo test the hypothesis that long-term postoperative dalteparin (Fragmin®, Pharmacia Corp) treatment improves primary patency of peripheral arterial bypass grafts (PABG) in lower limb ischemia patients on acetylsalicylic acid (ASA) treatment.DesignProspective randomised double blind multicenter study.Materials and methodsUsing a computer algorithm 284 patients with lower limb ischemia, most with pre-operative ischemic ulceration or partial gangrene, from 12 hospitals were randomised, after PABG, to 5000IU dalteparin or placebo injections once daily for 3 months. All patients received 75mg of ASA daily for 12 months. Graft patency was assessed at 1, 3 and 12 months.ResultsAt 1 year, 42 patients had died or were lost to follow-up. Compliance with the injection schedule was 80%. Primary patency rate, in the dalteparin versus the control group, respectively, was 83 versus 80% (n.s.) at 3 months and 59% for both groups at 12 months. Major complication rates and cardiovascular morbidity were not different between the two groups.ConclusionsIn patients on ASA treatment, long-term postoperative dalteparin treatment did not improve patency after peripheral artery bypass grafting. Therefore, low molecular weight heparin treatment cannot be recommended for routine use after bypass surgery for critical lower limb ischemia

Embedded Protostars in the Dust, Ice, and Gas In Time (DIGIT) Key Program: Continuum SEDs, and an Inventory of Characteristic Far-Infrared Lines from PACS Spectroscopy

We present 50-210 um spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 um SEDs, as part of the Dust, Ice, and Gas in Time (DIGIT) Key Program. Some sources exhibit up to 75 H2O lines ranging in excitation energy from 100-2000 K, 12 transitions of OH, and CO rotational lines ranging from J=14-13 up to J=40-39. [O I] is detected in all but one source in the entire sample; among the sources with detectable [O I] are two Very Low Luminosity Objects (VeLLOs). The mean 63/145 um [O I] flux ratio is 17.2 +/- 9.2. The [O I] 63 um line correlates with Lbol, but not with the time-averaged outflow rate derived from low-J CO maps. [C II] emission is in general not local to the source. The sample Lbol increased by 1.25 (1.06) and Tbol decreased to 0.96 (0.96) of mean (median) values with the inclusion of the Herschel data. Most CO rotational diagrams are characterized by two optically thin components ( = (0.70 +/- 1.12) x 10^49 total particles). N_CO correlates strongly with Lbol, but neither Trot nor N_CO(warm)/N_CO(hot) correlates with Lbol, suggesting that the total excited gas is related to the current source luminosity, but that the excitation is primarily determined by the physics of the interaction (e.g., UV- heating/shocks). Rotational temperatures for H2O ( = 194 +/- 85 K) and OH ( = 183 +/- 117 K) are generally lower than for CO, and much of the scatter in the observations about the best fit is attributed to differences in excitation conditions and optical depths amongst the detected lines.Comment: 58 pages, 37 figures; accepted to Ap

Folding Circular Permutants of IL-1β: Route Selection Driven by Functional Frustration

Interleukin-1β (IL-1β) is the cytokine crucial to inflammatory and immune response. Two dominant routes are populated in the folding to native structure. These distinct routes are a result of the competition between early packing of the functional loops versus closure of the β-barrel to achieve efficient folding and have been observed both experimentally and computationally. Kinetic experiments on the WT protein established that the dominant route is characterized by early packing of geometrically frustrated functional loops. However, deletion of one of the functional loops, the β-bulge, switches the dominant route to an alternative, yet, as accessible, route, where the termini necessary for barrel closure form first. Here, we explore the effect of circular permutation of the WT sequence on the observed folding landscape with a combination of kinetic and thermodynamic experiments. Our experiments show that while the rate of formation of permutant protein is always slower than that observed for the WT sequence, the region of initial nucleation for all permutants is similar to that observed for the WT protein and occurs within a similar timescale. That is, even permutants with significant sequence rearrangement in which the functional-nucleus is placed at opposing ends of the polypeptide chain, fold by the dominant WT “functional loop-packing route”, despite the entropic cost of having to fold the N- and C- termini early. Taken together, our results indicate that the early packing of the functional loops dominates the folding landscape in active proteins, and, despite the entropic penalty of coalescing the termini early, these proteins will populate an entropically unfavorable route in order to conserve function. More generally, circular permutation can elucidate the influence of local energetic stabilization of functional regions within a protein, where topological complexity creates a mismatch between energetics and topology in active proteins

Phonon-induced dephasing of localized optical excitations

The dynamics of strongly localized optical excitations in semiconductors is studied including electron-phonon interaction. The coupled microscopic equations of motion for the interband polarization and the carrier distribution functions contain coherent and incoherent contributions. While the coherent part is solved through direct numerical integration, the incoherent one is treated by means of a generalized Monte Carlo simulation. The approach is illustrated for a simple model system. The temperature and excitation energy dependence of the optical dephasing rate is analyzed and the results are compared to those of alternative approaches

Obesity and nocturnal gastro-oesophageal reflux are related to onset of asthma and respiratory symptoms

Several studies have identified obesity as a risk factor for asthma in both children and adults. An increased prevalence of asthma in subjects with gastro-oesophageal reflux (GOR) and obstructive sleep apnoea syndrome has also been reported. The aim of this investigation was to study obesity, nocturnal GOR and snoring as independent risk factors for onset of asthma and respiratory symptoms in a Nordic population. In a 5-10 yr follow-up study of the European Community Respiratory Health Survey in Iceland, Norway, Denmark, Sweden and Estonia, a postal questionnaire was sent to previous respondents. A total of 16,191 participants responded to the questionnaire. Reported onset of asthma, wheeze and night-time symptoms as well as nocturnal GOR and habitual snoring increased in prevalence along with the increase in body mass index (BMI). After adjusting for nocturnal GOR, habitual snoring and other confounders, obesity (BMI >30) remained significantly related to the onset of asthma, wheeze and night-time symptoms. Nocturnal GOR was independently related to the onset of asthma and in addition, both nocturnal GOR and habitual snoring were independently related to onset of wheeze and night-time symptoms. This study adds evidence to an independent relationship between obesity, nocturnal gastro-oesophageal reflux and habitual snoring and the onset of asthma and respiratory symptoms in adults