Natural orbitals and sparsity of quantum mutual information

Natural orbitals, defined in electronic structure and quantum chemistry as the (molecular) orbitals diagonalizing the one-particle reduced density matrix of the ground state, have been conjectured for decades to be the perfect reference orbitals to describe electron correlation. In the present work we applied the Wavefunction-Adapted Hamiltonian Through Orbital Rotation (WAHTOR) method to study correlated empirical ans\"atze for quantum computing. In all representative molecules considered, we show that the converged orbitals are coinciding with natural orbitals. Interestingly, the resulting quantum mutual information matrix built on such orbitals is also maximally sparse, providing a clear picture that such orbital choice is indeed able to provide the optimal basis to describe electron correlation. The correlation is therefore encoded in a smaller number of qubit pairs contributing to the quantum mutual information matrix.Comment: 11 pages + supplementary meteria

Pulse variational quantum eigensolver on cross-resonance based hardware

State-of-the-art noisy digital quantum computers can only execute short-depth quantum circuits. Variational algorithms are a promising route to unlock the potential of noisy quantum computers since the depth of the corresponding circuits can be kept well below hardware-imposed limits. Typically, the variational parameters correspond to virtual $R_Z$ gate angles, implemented by phase changes of calibrated pulses. By encoding the variational parameters directly as hardware pulse amplitudes and durations we succeed in further shortening the pulse schedule and overall circuit duration. This decreases the impact of qubit decoherence and gate noise. As a demonstration, we apply our pulse-based variational algorithm to the calculation of the ground state of different hydrogen-based molecules (H$_2$, H$_3$ and H$_4$) using IBM cross-resonance-based hardware. We observe a reduction in schedule duration of up to $5\times$ compared to CNOT-based Ans\"atze, while also reducing the measured energy. In particular, we observe a sizable improvement of the minimal energy configuration of H$_3$ compared to a CNOT-based variational form. Finally, we discuss possible future developments including error mitigation schemes and schedule optimizations, which will enable further improvements of our approach paving the way towards the simulation of larger systems on noisy quantum devices

Increasing the source/sink ratio in Vitis vinifera (cv Sangiovese) induces extensive transcriptome reprogramming and modifies berry ripening

<p>Abstract</p> <p>Background</p> <p>Cluster thinning is an agronomic practice in which a proportion of berry clusters are removed from the vine to increase the source/sink ratio and improve the quality of the remaining berries. Until now no transcriptomic data have been reported describing the mechanisms that underlie the agronomic and biochemical effects of thinning.</p> <p>Results</p> <p>We profiled the transcriptome of <it>Vitis vinifera </it>cv. Sangiovese berries before and after thinning at veraison using a genome-wide microarray representing all grapevine genes listed in the latest V1 gene prediction. Thinning increased the source/sink ratio from 0.6 to 1.2 m²leaf area per kg of berries and boosted the sugar and anthocyanin content at harvest. Extensive transcriptome remodeling was observed in thinned vines 2 weeks after thinning and at ripening. This included the enhanced modulation of genes that are normally regulated during berry development and the induction of a large set of genes that are not usually expressed.</p> <p>Conclusion</p> <p>Cluster thinning has a profound effect on several important cellular processes and metabolic pathways including carbohydrate metabolism and the synthesis and transport of secondary products. The integrated agronomic, biochemical and transcriptomic data revealed that the positive impact of cluster thinning on final berry composition reflects a much more complex outcome than simply enhancing the normal ripening process.</p

Natural Orbitals and Sparsity of Quantum Mutual Information

Natural orbitals, defined in electronic structure and quantum chemistry as the molecular orbitals diagonalizing the one-particle reduced density matrix of the ground state, have been conjectured for decades to be the perfect reference orbitals to describe electron correlation. In the present work we applied the Wave function-Adapted Hamiltonian Through Orbital Rotation (WAHTOR) method to study correlated empirical ansätze for quantum computing. In all representative molecules considered, we show that the converged orbitals are coinciding with natural orbitals. Interestingly, the resulting quantum mutual information matrix built on such orbitals is also maximally sparse, providing a clear picture that such orbital choice is indeed able to provide the optimal basis to describe electron correlation. The correlation is therefore encoded in a smaller number of qubit pairs contributing to the quantum mutual information matrix

H/D Isotope Effects Reveal Factors Controlling Catalytic Activity in Co-Based Oxides for Water Oxidation

Understanding the mechanism for electrochemical water oxidation is important for the development of more efficient catalysts for artificial photosynthesis. A basic step is the proton-coupled electron transfer, which enables accumulation of oxidizing equivalents without buildup of a charge. We find that substituting deuterium for hydrogen resulted in an 87% decrease in the catalytic activity for water oxidation on Co-based amorphous-oxide catalysts at neutral pH, while ¹⁶O-to-¹⁸O substitution lead to a 10% decrease. In situ visible and quasi-in situ X-ray absorption spectroscopy reveal that the hydrogen-to-deuterium isotopic substitution induces an equilibrium isotope effect that shifts the oxidation potentials positively by approximately 60 mV for the proton coupled Co^II/III and Co^III/IV electron transfer processes. Time-resolved spectroelectrochemical measurements indicate the absence of a kinetic isotope effect, implying that the precatalytic proton-coupled electron transfer happens through a stepwise mechanism in which electron transfer is rate-determining. An observed correlation between Co oxidation states and catalytic current for both isotopic conditions indicates that the applied potential has no direct effect on the catalytic rate, which instead depends exponentially on the average Co oxidation state. These combined results provide evidence that neither proton nor electron transfer is involved in the catalytic rate-determining step. We propose a mechanism with an active species composed by two adjacent Co^IV atoms and a rate-determining step that involves oxygen–oxygen bond formation and compare it with models proposed in the literature

National, longitudinal NASCITA birth cohort study: prevalence of overweight at 12 months of age in children born healthy

Objective To estimate the prevalence of overweight at 12 months in an Italian birth cohort and to identify factors related to an increased likelihood of being overweight.Methods The Italian NASCITA birth cohort was analysed. Infants were classified as underweight (&lt;5th), normal weight (5–84th) and overweight (≥85th centile) at 12 months of age according to the WHO percentiles of body mass index (BMI) and the prevalence of overweight was estimated. To test the association between the chance of being overweight and parental and newborn characteristics, and infant feeding, healthy newborns (no preterm/low birth weight and with no malformations), with appropriate-for-gestational-age birth weight were selected, and univariate and multivariate analyses were performed.Results The prevalence of overweight was 23.5% (95% CI 22.2% to 24.8%) in all cohort members with 12-month data (N=4270), and 23.1% in the appropriate-for-gestational age subsample (N=2835).A big infant appetite (OR 3.92, 95% CI 2.40 to 6.40) and living in southern Italy (OR 1.58, 95% CI 1.29 to 1.94) were the main variables associated with a greater likelihood of being overweight. Breastfeeding practice did not influence the chance of being overweight, but was associated with an increase (exclusive breast feeding for at least 6 months) or a decrease (breast feeding for at least 12 months) in BMI z score at 12 months.Conclusions The sociodemographic factors (eg, area of residence, maternal employment status) seem to be the most relevant determinants influencing the chance of being overweight at 12 months. Early interventions, with particular attention to vulnerable families, may be helpful in preventing childhood and adult obesity

Postpartum depression screening in mothers and fathers at well-child visits: a feasibility study within the NASCITA cohort

Objective To assess the feasibility of the family paediatrician’s (FP) role in identifying the signs of postpartum depression in parents in time to guarantee child well-being.Design, setting and participants Data for this observational prospective study were collected within the NASCITA (NAscere e creSCere in ITAlia) cohort. During the first visit, paediatricians collected sociodemographic data regarding the parents and information about their health status, the pregnancy and the delivery. Whooley questions were administered during the first and second visits (scheduled 60–90 days after childbirth). Moreover, on the third visit (5–7 months after childbirth) the FP was asked to answer ‘yes’ or ‘no’ to a question on the parental postpartum depression, based on his knowledge and on the acquired information.Results In 2203 couples who completed the assessment, 529 mothers (19.9%), 141 fathers (6.3%) and 110 (5%) couples reported any depressive symptomatology. Of these, 141 mothers (5.3% of the total sample) and 18 fathers (0.8% of the total sample) were classified as ‘likely depressed’. An association was found between maternal postnatal depressive symptoms and having a diagnosed psychiatric disorder during pregnancy (OR 9.49, 95% CI: 3.20 to 28.17), not exclusively breastfeeding at hospital discharge (OR 1.76, 95% CI: 1.19 to 2.61) and the presence of child sleeping disorders at 3 (OR 2.46, 95% CI: 1.41 to 4.28) and 6 months (OR 2.18, 95% CI: 1.37 to 3.47). Another significant predictor of postpartum depression was being primiparous (OR 1.99, 95% CI: 1.31 to 3.02). Concerning the fathers, a significant association was reported only between likely depressed fathers and child sleeping disorders at 3 months (OR 7.64, 95% CI: 2.92 to 19.97). Moreover, having a likely depressed partner was strongly associated with depressive symptoms in fathers (OR 85.53, 95% CI 26.83 to 272.69).Conclusions The findings of this study support the feasibility of an active screening programme for parental postnatal depression during well-child visits as an integral part of postpartum care.Trial registration number NCT03894566; Pre-results

The grapevine VviPrx31 peroxidase as a candidate gene involved in anthocyanin degradation in ripening berries under high temperature

Anthocyanin levels decline in some red grape berry varieties ripened under high-temperature conditions, but the underlying mechanism is not yet clear. Here we studied the effects of two different temperature regimes, representing actual Sangiovese (Vitis vinifera L.) viticulture regions, on the accumulation of mRNAs and enzymes controlling berry skin anthocyanins. Potted uniform plants of Sangiovese were kept from veraison to harvest, in two plastic greenhouses with different temperature conditions. The low temperature (LT) conditions featured average and maximum daily air temperatures of 20 and 29 °C, respectively, whereas the corresponding high temperature (HT) conditions were 22 and 36 °C, respectively. The anthocyanin concentration at harvest was much lower in HT berries than LT berries although their profile was similar under both conditions. Under HT conditions, the biosynthesis of anthocyanins was suppressed at both the transcriptional and enzymatic levels, but peroxidase activity was higher. This suggests that the low anthocyanin content of HT berries reflects the combined impact of reduced biosynthesis and increased degradation, particularly the direct role of peroxidases in anthocyanin catabolism. Overexpression of VviPrx31 decreased anthocyanin contents in Petunia hybrida petals under heat stress condition. These data suggest that high temperature can stimulate peroxidase activity thus anthocyanin degradation in ripening grape berries

La terapia insulinica sottocutanea continua (CSII) in Italia. Terza indagine nazionale

Continuous subcutaneous insulin infusion (CSII) is increasingly being used worldwide, mostly thanks to technical improvements. This study examined the current status of CSII in Italy. Physicians in charge of 272 diabetes centers caring for patients using CSII were sent a questionnaire investigating clinical features, pump technology and management of these patients; a large proportion (217 centers, 79.8%) joined the study. By end-April 2013, data had been collected on 10152 patients treated with CSII; 98.2% had type 1 diabetes, 82.4% were adults, 57% female. Only just over half the centers (59%) managed more than 20 CSII patients each. The distribution of patients varied widely both among and within different regions. The main indication for CSII was the de- sire to improve glycemic control. Dropouts (8.65%) were mainly due to difficulties with pump wearability or non-optimal glycemic control. Among CSII patients 61% used a traditional pump, 39% a sensor augmented pump. Only 68% used the CSII advanced functions and glucose sensors were used twelve days per month on average. Round-the-clock assistance was guaranteed in 81% of centers; a full diabetes team followed patients in only 40% of adult-care centers and 50% of pediatric units. CSII is increasingly used in Italy, by adults and pediatric patients. However, further work is needed to unify treatment strategies throughout the country and to encourage optimal pump use and applications