Dynamical correlations in electronic transport through a system of coupled quantum dots

Current auto- and cross-correlations are studied in a system of two capacitively coupled quantum dots. We are interested in a role of Coulomb interaction in dynamical correlations, which occur outside the Coulomb blockade region (for high bias). After decomposition of the current correlation functions into contributions between individual tunneling events, we can show which of them are relevant and lead to sub-/supper-Poissonian shot noise and negative/positive cross-correlations. The results are differentiated for a weak and strong inter-dot coupling. Interesting results are for the strong coupling case when electron transfer in one of the channel is strongly correlated with charge drag in the second channel. We show that cross-correlations are non-monotonic functions of bias voltage and they are in general negative (except some cases with asymmetric tunnel resistances). This is effect of local potential fluctuations correlated by Coulomb interaction, which mimics the Pauli exclusion principle

CMB Temperature Polarization Correlation and Primordial Gravitational Waves

We examine the use of the CMB's TE cross correlation power spectrum as a complementary test to detect primordial gravitational waves (PGWs). The first method used is based on the determination of the lowest multipole, $\ell_0$, where the TE power spectrum, $C_{\ell}^{TE}$, first changes sign. The second method uses Wiener filtering on the CMB TE data to remove the density perturbations contribution to the TE power spectrum. In principle this leaves only the contribution of PGWs. We examine two toy experiments (one ideal and another more realistic) to see their ability to constrain PGWs using the TE power spectrum alone. We found that an ideal experiment, one limited only by cosmic variance, can detect PGWs with a ratio of tensor to scalar metric perturbation power spectra $r=0.3$ at 99.9% confidence level using only the TE correlation. This value is comparable with current constraints obtained by WMAP based on the $2\sigma$ upper limits to the B-mode amplitude. We demonstrate that to measure PGWs by their contribution to the TE cross correlation power spectrum in a realistic ground based experiment when real instrumental noise is taken into account, the tensor-to-scalar ratio, $r$, should be approximately three times larger.Comment: 13 pages, 13 figures, version matches published version. Combined with 0710.365

Charge fluctuations and feedback effect in shot noise in a Y-terminal system

We investigate a dynamical Coulomb blockade effect and its role in the enhancement of current-current correlations in a three-terminal device with a multilevel splitter, as well as with two quantum dots. Spectral decomposition analysis shows that in the Y-terminal system with a two level ideal splitter, charge fluctuations at a level with a lowest outgoing tunneling rate are responsible for a super-Poissonian shot noise and positive cross-correlations. Interestingly, for larger source-drain voltages, electrons are transferred as independent particles, when three levels participate in transport, and double occupancy is allowed. We can explain compensation of the current correlations as the interplay between different bunching and antibunching processes by performing a spectral decomposition of the correlation functions for partial currents flowing through various levels. In the system with two quantum dots acting as a splitter, a long range feedback effect of fluctuating potentials leads to the dynamical Coulomb blockade and an enhancement of shot noise.Comment: 15 pages, 8 figure

Arrhythmic risk profile and outcomes of patients undergoing cardiac sympathetic denervation for recurrent monomorphic ventricular tachycardia after ablation

Background Cardiac sympathetic denervation (CSD) has been used as a bailout strategy for refractory ventricular tachycardia (VT). Risk of VT recurrence in patients with scar-related monomorphic VT referred for CSD and the extent to which CSD can modify this risk is unknown. We aimed to quantify arrhythmia recurrence risk and impact of CSD in this population. Methods and Results Adjusted competing risk time to event models were developed to adjust for risk of VT recurrence and sustained VT/implantable cardioverter-defibrillator shocks after VT ablation based on patient comorbidities at the time of VT ablation. Adjusted VT and implantable cardioverter-defibrillator shock recurrence rates were estimated for the subgroup who subsequently required CSD after ablation. The expected adjusted recurrence rates were then compared with the observed rates after CSD. Data from 381 patients with scar-mediated monomorphic VT who underwent VT ablation were analyzed, excluding patients with polymorphic VT. Sixty eight patients underwent CSD for recurrent VT. CSD reduced the expected adjusted VT recurrence rate by 36% (expected rate of 5.61 versus observed rate of 3.58 per 100 person-months, P=0.01) and the sustained VT/implantable cardioverter-defibrillator shock rates by 34% (expected rate of 4.34 versus observed 2.85 per 100 person-months, P=0.03). The median number of sustained VT/implantable cardioverter-defibrillator shocks in the year before versus the year after CSD was reduced by 90% (10 versus 1, P<0.0001). Conclusions Patients referred for CSD for refractory scar-mediated monomorphic VT are at a higher risk of VT recurrence after ablation as compared with those not requiring CSD, mostly because of their cardiac comorbidities. CSD significantly reduced both the expected risk of recurrences and VT burden

Nitrogen sources on TPOMW valorization through solid state fermentation performed by Yarrowia lipolytica

This manuscript reports the valorization of two-phase olive mill waste (TPOMW) as raw material and carbon source for solid state fermentation using Yarrowia lipolytica as biocatalyst. Due to its chemical characteristics, a combination of different raw materials (TPOMW and wheat bran, WB) was evaluated and two distinct nitrogen sources were applied as supplementation for lipase production. A TPOMW/WB ratio of 1:1 and supplementation with ammonium sulfate was chosen as the best condition. The productivity in 24 h reached 7.8 U/gh and, after four days of process, only decreased about 35%. Process pH ranged from 5.5-5.9, remaining in an acid range. Thus, the successful use of TPOMW, a watery solid by-product with high content of lipids, as raw material for Yarrowia lipolytica growth and lipase production provided an environmental friendly alternative to valorize such waste.The authors kindly acknowledge the financial aid and research scholarships given by CAPES. Maria Alice Zarur Coelho thanks CNPq (Proc. 308890/ 2013-2)

Human germline heterozygous gain-of-function STAT6 variants cause severe allergic disease

sharma et al. define a new primary atopic disorder caused by heterozygous gain-of-function variants in STAT6. this results in severe, early-onset allergies, and is seen in 16 patients from 10 families. Anti-IL-4R & alpha; antibody and JAK inhibitor treatment were highly effective.STAT6 (signal transducer and activator of transcription 6) is a transcription factor that plays a central role in the pathophysiology of allergic inflammation. we have identified 16 patients from 10 families spanning three continents with a profound phenotype of early-life onset allergic immune dysregulation, widespread treatment-resistant atopic dermatitis, hypereosinophilia with esosinophilic gastrointestinal disease, asthma, elevated serum IgE, IgE-mediated food allergies, and anaphylaxis. the cases were either sporadic (seven kindreds) or followed an autosomal dominant inheritance pattern (three kindreds). all patients carried monoallelic rare variants in STAT6 and functional studies established their gain-of-function (GOF) phenotype with sustained STAT6 phosphorylation, increased STAT6 target gene expression, and T(H)2 skewing. Precision treatment with the anti-IL-4R & alpha; antibody, dupilumab, was highly effective improving both clinical manifestations and immunological biomarkers. this study identifies heterozygous GOF variants in STAT6 as a novel autosomal dominant allergic disorder. We anticipate that our discovery of multiple kindreds with germline STAT6 GOF variants will facilitate the recognition of more affected individuals and the full definition of this new primary atopic disorder

Enzyme production from food wastes using a biorefinery concept

According to Food and Agricultural Organization (FAO), one-third of food produced globally for human consumption (nearly 1.3 billion tonnes) is lost along the food supply chain. In many countries food waste is currently landfilled or incinerated together with other combustible municipal wastes for possible recovery of energy. However, these two options are facing more and more economic and environmental stresses. Due to its organic- and nutrient-rich nature, theoretically food waste can be converted to valuable products (e.g. bio-products such as methane, hydrogen, ethanol, enzymes, organic acids, chemicals and fuels) through various fermentation processes. Such conversion of food waste is potentially more profitable than its conversion to animal feed or transportation fuel. Food waste valorisation has therefore gained interest, with value added bio-products such as methane, hydrogen, ethanol, enzymes, organic acids, chemicals, and fuels. Therefore, the aim of this review is to provide information on the food waste situation with emphasis on Asia–Pacific countries and the state of the art food waste processing technologies to produce enzymes