Probabilistic Adaptive Computation Time

We present a probabilistic model with discrete latent variables that control the computation time in deep learning models such as ResNets and LSTMs. A prior on the latent variables expresses the preference for faster computation. The amount of computation for an input is determined via amortized maximum a posteriori (MAP) inference. MAP inference is performed using a novel stochastic variational optimization method. The recently proposed Adaptive Computation Time mechanism can be seen as an ad-hoc relaxation of this model. We demonstrate training using the general-purpose Concrete relaxation of discrete variables. Evaluation on ResNet shows that our method matches the speed-accuracy trade-off of Adaptive Computation Time, while allowing for evaluation with a simple deterministic procedure that has a lower memory footprint

The role of the Fe/Mo cations ordering degree and oxygen non-stoichiometry on the formation of the crystalline and magnetic structure of Sr2FeMoO6‒δ

Single-phase Sr2FeMoO6-δ powders with various oxygen indices (δ) and degrees of the superstructural ordering (P) of the Fe/Mo cations were obtained from SrFeO2.52 and SrMoO4 reagents via solid-state synthesis. It has been established by means of the x-ray and neutron diffraction that, upon reducing the oxygen content and enhancing the superstructural ordering, the lengths of the Fe–O1 and Mo–O2 bonds in the crystal lattice increase, whereas the Fe–O2 and Mo–O1 bond lengths decrease. At the same time, the volume of the unit cell is reduced, which indicates an enhancement of the covalency degree of the bonds and stimulates a redistribution of the electron density, as well as an increase of the concentration of the spin-down charge carriers located in the conduction band on the Mo(t2g)↓ orbitals. This circumstance leads to an increase of the density of states at the Fermi level, accompanied by an amplification of the exchange interaction and elevation of the Curie temperature, which points to the leading role of the spin-polarized charge carriers at the Fermi level in the exchange interaction.publishe

The physical parameters of clumps associated with class I methanol masers

We present a study of the association between class I methanol masers and cold dust clumps from the ATLASGAL survey. It was found that almost 100% of class I methanol masers are associated with objects listed in the ATLASGAL compact source catalog. We find a statistically significant difference in the flux density, luminosity, number and column density and temperature distributions of ATLASGAL sources associated with 95/44 GHz methanol masers compared with those ATLASGAL sources devoid of 95 GHz methanol masers. The masers tend to arise in clumps with higher densities, luminosities and temperatures compared with both the full sample of ATLASGAL clumps, as well as the sample of ATLASGAL sources that were cross-matched with positions previously searched for methanol masers but with no detections. Comparison between the peak position of ATLASGAL clumps and the interferometric positions of the associated class I and II methanol masers reveals that class I masers are generally located at larger physical distances from the peak submillimetre emission than class II masers. We conclude that the tight association between ATLASGAL sources and class I methanol masers may be used as a link toward understanding the conditions of the pumping of these masers and evolutionary stages at which they appear

Salivary gland immunohistochemistry vs substantia nigra sonography: comparative analysis of diagnostic significance

Introduction. Parkinson's disease (PD) urges for new instrumental methods of diagnosis. Transcranial sonography of the substantia nigra (SN TCS) is an established method for early PD diagnosis but its application is limited. Recently, biopsies (primarily that of salivary gland) and test for abnormal -synuclein are suggested to verify PD. Materials and methods. We assessed 12 individuals with PD, HoehnYahr 2.3 0.4. The assessments included: UPDRS, NMSQ, NMSS, RBDSQ, PDQ-8, MoCA, and HADS scoring; SN TCS; and sublingual gland immunohistochemistry for phosphorylated -synuclein (PS-129) with automated morphometric analysis. Results. Substantia nigra hyperechogenicity was shown in 75% of patients whereas biopsy revealed PS-129 in 100% of patients. Echogenic area of the substantia nigra was 0.24 [0.21; 0.3] cm2. PS-129 inclusion area varied from 28.47 [27.55; 96.26] to 238.77 [234.13; 272.49] m2, and PS-129 proportion varied from 13.4% to 93.4% of the nervous fiber area across the patients. We found relations between PS-129 and NMSQ (r = 0.8; p 0.001), NMSS (r = 0.9; p 0.001), PDQ-8 (r = 0.7; p = 0.003), UPDRS-I (r = 0.7; p = 0.009), UPDRS-II (r = 0.6; p = 0.03), and HADS (anxiety r = 0.8; p = 0.002; depression r = 0.6; p = 0.04) scores. Conclusion. The results demonstrate a higher biopsy sensitivity as compared to SN TCS. Automated morphometric analysis has been newly applied to assess PS-129 occurrence. Immunohistochemistry results are directly related to non-motor symptom severity, which may indicate high probability of PS-129 presence and diagnosis confirmation in early disease