Spiking neural network model of reinforcement learning in the honeybee implemented on the GPU

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Calculation of the Infrared Intensity of Crystalline Systems. A Comparison of Three Strategies Based on Berry Phase, Wannier Function, and Coupled-Perturbed Kohn–Sham Methods

Three alternative strategies for the calculation of the IR intensity of crystalline systems, as determined by Born charges, have been implemented in the Crystal code, using a Gaussian type basis set. One uses the Berry phase (BP) algorithm to compute the dipole moment; another does so, instead, through well localized crystalline orbitals (Wannier functions, WF); and the third is based on a coupled perturbed Hartree–Fock or Kohn–Sham procedure (CP). In WF and BP, the derivative of the dipole moment with respect to the atomic coordinates is evaluated numerically, whereas in CP it is analytical. In the three cases, very different numerical schemes are utilized, so that the equivalence of the obtained IR intensities is not ensured a priori but instead is the result of the high numerical accuracy of the many computational steps involved. The main aspects of the three schemes are briefly recalled, and the dependence of the results on the computational parameters (number of k points in reciprocal space, tolerances for the truncation of the Coulomb and exchange series, and so on) is documented. It is shown that in standard computational conditions the three schemes produce IR intensities that differ by less than 1%; this difference can be reduced by an order of magnitude by acting on the parameters that control the accuracy of the calculation. A large unit cell system (80 atoms per cell) is used to document the relative cost of the three schemes. Within the current implementation the BP strategy, despite its seminumerical nature, is the most efficient choice. That is because it is the oldest implementation, and it is based on the simplest of the three algorithms. Thus, parallelism and other schemes for improving efficiency have, so far, been implemented to a lesser degree in the other two cases

In Vivo Evaluation of Cervical Stiffness Evolution during Induced Ripening Using Shear Wave Elastography, Histology and 2 Photon Excitation Microscopy: Insight from an Animal Model

Prematurity affects 11% of the births and is the main cause of infant mortality. On the opposite case, the failure of induction of parturition in the case of delayed spontaneous birth is associated with fetal suffering. Both conditions are associated with precocious and/or delayed cervical ripening. Quantitative and objective information about the temporal evolution of the cervical ripening may provide a complementary method to identify cases at risk of preterm delivery and to assess the likelihood of successful induction of labour. In this study, the cervical stiffness was measured in vivo in pregnant sheep by using Shear Wave Elastography (SWE). This technique assesses the stiffness of tissue through the measurement of shear waves speed (SWS). In the present study, 9 pregnant ewes were used. Cervical ripening was induced at 127 days of pregnancy (term: 145 days) by dexamethasone injection in 5 animals, while 4 animals were used as control. Elastographic images of the cervix were obtained by two independent operators every 4 hours during 24 hours after injection to monitor the cervical maturation induced by the dexamethasone. Based on the measurements of SWS during vaginal ultrasound examination, the stiffness in the second ring of the cervix was quantified over a circular region of interest of 5 mm diameter. SWS was found to decrease significantly in the first 4–8 hours after dexamethasone compared to controls, which was associated with cervical ripening induced by dexamethasone (from 1.779 m/s ± 0.548 m/s, p < 0.0005, to 1.291 m/s ± 0.516 m/s, p < 0.000). Consequently a drop in the cervical elasticity was quantified too (from 9.5 kPa ± 0.9 kPa, p < 0.0005, to 5.0 kPa ± 0.8 kPa, p < 0.000). Moreover, SWE measurements were highly reproducible between both operators at all times. Cervical ripening induced by dexamethasone was confirmed by the significant increase in maternal plasma Prostaglandin E2 (PGE2), as evidenced by the assay of its metabolite PGEM. Histological analyses and two-photon excitation microscopy, combining both Second Harmonic Generation (SHG) and Two-photon Fluorescence microscopy (2PF) contrasts, were used to investigate, at the microscopic scale, the structure of cervical tissue. Results show that both collagen and 2PF-active fibrillar structures could be closely related to the mechanical properties of cervical tissue that are perceptible in elastography. In conclusion, SWE may be a valuable method to objectively quantify the cervical stiffness and as a complementary diagnostic tool for preterm birth and for labour induction success

Nitrogen interstitial defects in silicon. A quantum mechanical investigation of the structural, electronic and vibrational properties

The vibrational features of eight interstitial nitrogen related defects in silicon have been investigated at the first principles quantum mechanical level by using a periodic supercell approach, a hybrid functionals, an all electron Gaussian type basis set and the Crystal code. The list includes defects that will be indicated as Ni (one N atom forming a bridge between two Si atoms), Ni-Ns (one interstitial and one substitutional N atom linked to the same Si atom), Ni-Ni (two Ni defects linked to the same couple of silicon atoms) and Ni-Sii-Ni (two Ni defects linked to the same interstitial silicon atom). Four 〈0 0 1〉 split interstitial (dumbbell) defects have also been considered, in which one lattice atom splits in two, and as a result the two interstitial atoms are three fold coordinated: they are two N (indicated as IN-N), one N and one Si (IN-Si), one N and one C (IC-N). For comparison, also the case with two Si atoms (ISi-Si) has been included. Four of these eight defects have unpaired electrons, and have been described through the UHF (Unrestricted Hartree-Fock like) computational scheme. The local defect geometry and the charge and spin density distributions have been analyzed. For the first time, intensities of IR and Raman spectra were calculated along with the frequencies, and this is crucial for the comparison of theoretical simulations with experiments. All these defects present very characteristic features in their IR spectrum, dominated by one or two very intense peaks. It has been possible to find a simulated counterpart to each one of the five peaks reported by Stein in 1985 (Applied Physics Letters, 47, 1339), and then to establish a correspondence between the microscopic structure of the defects and the IR intense peaks. The Raman spectra are in all cases dominated by the perfect silicon peak at about 530 cm−1, and are then not very useful for the characterization of the defects.Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

IL-12 regulates type 3 immunity through interfollicular keratinocytes in psoriasiform inflammation.

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Clinicopathological characteristics and disease chronicity in native kidney biopsies in Flanders

Lay Summary The Flemish Collaborative Glomerulonephritis Group (FCGG) registry collects information on patients that undergo kidney biopsy in the region of Flanders in Belgium. The registry summarizes the underlying diagnoses in patients that present with symptoms of kidney disease (e.g. blood and/or protein in the urine or decreased kidney function). Additionally, the registry also collects information on the degree of chronic damage on kidney biopsy. This is important because chronic damage may lead to kidney failure. From 2017 until 2019, a total of 2054 adult biopsies were analyzed, while chronic damage could be analyzed in 898 biopsies. We found that the underlying causes of severe kidney disease were similar to studies performed in other European countries. Importantly, we found that increasing age, reduced kidney function and certain diagnoses are associated with more chronic damage on kidney biopsy. This information may be useful to doctors in clinical practice, in both Belgium and Europe. Background The Flemish Collaborative Glomerulonephritis Group (FCGG) registry provides complete population data on kidney disease epidemiology in the region of Flanders (Belgium), as it captures all native kidney biopsies performed in its population of 6.5 million inhabitants. Methods From 2017 until 2019, 2054 adult kidney biopsies were included from 26 nephrology centers (one biopsy per patient). Data on nephrotic and nephritic syndrome were available in 1992 and 2026 biopsies, respectively. In a subgroup of 898 biopsies containing >= 10 glomeruli from 2018 to 2019, disease chronicity was graded using the Mayo Clinic Chronicity Score (MCCS). The association between clinical variables and MCCS was determined using simple and multiple linear regression models. Results Nephrotic syndrome (present in 378 patients, 19.0%) was most frequently caused by minimal change disease in younger patients (18-44 years), membranous nephropathy in older patients (45-74 years) and amyloidosis in the elderly (>75 years). Nephritic syndrome (present in 421 patients, 20.8%) was most frequently caused by immunoglobulin A nephropathy (IgAN) in younger patients (18-64 years) and ANCA-associated vasculitis (AAV) in older patients (>64 years). AAV and IgAN were the most frequent underlying diagnoses in biopsies in which crescents were identified. In multivariable analysis, acute and chronic kidney disease and diagnoses of diabetic kidney disease, nephrosclerosis and hyperoxaluria/hypercalcemic nephropathy were associated with the highest MCCS increases. Conclusions The FCGG registry validates data from previous Western European registries and provides a snapshot of disease chronicity in the whole biopsied Flemish population