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Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly–L-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree–Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints – even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's), all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å 2 as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements – an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

The energy cost to swim a unit distance ( C sw ) is given by the ratio where is the net metabolic power and v is the swimming speed. The contribution of the aerobic and anaerobic energy sources to in swimming competitions is independent of swimming style, gender or skill and depends essentially upon the duration of the exercise. C sw is essentially determined by the hydrodynamic resistance ( W d ): the higher W d the higher C sw ; and by the propelling efficiency ( η P ): the higher η P the lower C sw . Hence, all factors influencing W d and/or η P result in proportional changes in C sw . Maximal metabolic power and C sw are the main determinants of swimming performance; an improvement in a subject’s best performance time can more easily be obtained by a reduction of C sw rather than by an (equal) increase in (in either of its components, aerobic or anaerobic). These sentences, which constitute a significant contribution to today’s knowledge about swimming energetics, are based on the studies that Professor Pietro Enrico di Prampero and his co-workers carried out since the 1970s. This paper is devoted to examine how this body of work helped to improve our understanding of this fascinating mode of locomotion.

When exercising in the severe‐intensity domain, oxygen uptake (V̇O2) does not reach a steady state since it slowly and continuously drifts due to the appearance of the slow component of V̇O2 (V̇O2sc). V̇O2sc has been customarily evaluated by measuring V̇O2 using pulmonary gas exchanges, including the contribution of the metabolic expenditure of the respiratory muscles, heart, and muscles recruited for stabilizing the posture, etc. We assessed the muscular oxygen uptake (mV̇O2, in μM·s−1) of flexor digitorum superficialis by using near‐infrared spectroscopy (NIRS) during brief arterial occlusions imposed over repeated, cyclic isometric hand grips performed at two different percentages (25%; 50%) of maximal voluntary contraction (MVC). mV̇O2 was significantly larger at 50% MVC than at 25% MVC at all the time points (p < 0.05) as expected, apart from the values at the 3rd minute. Secondly, mV̇O2 increased linearly at 25% of MVC (mV̇O2 = 1.73 + 0.108 × min; r2 = 0.993; p < 0.0033) and at 50% of MVC (mV̇O2 = 2.41 + 0.240 × min; r2 = 0.956; p < 0.0223) from the 3rd minute of exercise onwards; the slopes of the two linear regressions were significantly different (p < 0.0232). We suggest that the V̇O2sc of mV̇O2 occurring during intermittent isometric contractions can be assessed with NIRS during brief complete arterial occlusions regularly interspersed in the series of contractions. In addition, the technique can discriminate the rates of increase of mV̇O2 corresponding to different percentages of MVC. The slow component of muscle oxygen consumption can be assessed with NIRS during brief arterial occlusions.

State-of-the-art physics experiments require high-resolution, low-noise, and low-threshold detectors to achieve competitive scientific results. However, experimental environments invariably introduce sources of noise, such as electrical interference or microphonics. The sources of this environmental noise can often be monitored by adding specially designed “auxiliary devices” (e.g. microphones, accelerometers, seismometers, magnetometers, and antennae). A model can then be constructed to predict the detector noise based on the auxiliary device information, which can then be subtracted from the true detector signal. Here, we present a multivariate noise cancellation algorithm which can be used in a variety of settings to improve the performance of detectors using multiple auxiliary devices. To validate this approach, we apply it to simulated data to remove noise due to electromagnetic interference and microphonic vibrations. We then employ the algorithm to a cryogenic light detector in the laboratory and show an improvement in the detector performance. Finally, we motivate the use of nonlinear terms to better model vibrational contributions to the noise in thermal detectors. We show a further improvement in the performance of a particular channel of the CUORE detector when using the nonlinear algorithm in combination with optimal filtering techniques.

Two-neutrino double electron capture (2 ν ECEC) is a second-order weak-interaction process with a predicted half-life that surpasses the age of the Universe by many orders of magnitude 1 . Until now, indications of 2 ν ECEC decays have only been seen for two isotopes 2 – 5 , 78 Kr and 130 Ba, and instruments with very low background levels are needed to detect them directly with high statistical significance 6 , 7 . The 2 ν ECEC half-life is an important observable for nuclear structure models 8 – 14 and its measurement represents a meaningful step in the search for neutrinoless double electron capture—the detection of which would establish the Majorana nature of the neutrino and would give access to the absolute neutrino mass 15 – 17 . Here we report the direct observation of 2 ν ECEC in 124 Xe with the XENON1T dark-matter detector. The significance of the signal is 4.4 standard deviations and the corresponding half-life of 1.8 × 10 22  years (statistical uncertainty, 0.5 × 10 22  years; systematic uncertainty, 0.1 × 10 22  years) is the longest measured directly so far. This study demonstrates that the low background and large target mass of xenon-based dark-matter detectors make them well suited for measuring rare processes and highlights the broad physics reach of larger next-generation experiments 18 – 20 . Two-neutrino double electron capture is observed experimentally in 124 Xe with the XENON1T detector, yielding a half-life of 1.8 × 10 22 years.

Climate change and human activities are increasingly threatening water resources. In particular sub-alpine lakes are fundamental not only for tourism or other economical activities, but also as a source of water. In this context, there is a strong need to monitor such resources to understand, study and react to known and unknown impacts, so that appropriate mitigation actions can be taken. Unfortunately, although monitoring data already exist for many of these lakes, the information is archived in different formats and servers undermining the full exploitation of data and preventing a more efficient data management. The aim of this work is to improve this situation by implementing a system that integrates and standardizes data coming from different sources. In addition, the system integrates web based tools that estimate lake state indicators using open source software and standard. Thanks to this system, it will be possible to exploit the data potential more fully. This paper focuses on the achievements reached by the research carried out on Lake Lugano in the context of the project SIMILE after two years of work.

The DARWIN observatory is a proposed next-generation experiment to search for particle dark matter and for the neutrinoless double beta decay of 136 Xe. Out of its 50 t total natural xenon inventory, 40 t will be the active target of a time projection chamber which thus contains about 3.6 t of 136 Xe. Here, we show that its projected half-life sensitivity is 2.4 × 10 27 year , using a fiducial volume of 5 t of natural xenon and 10 year of operation with a background rate of less than 0.2 events/(t  ·  year) in the energy region of interest. This sensitivity is based on a detailed Monte Carlo simulation study of the background and event topologies in the large, homogeneous target. DARWIN will be comparable in its science reach to dedicated double beta decay experiments using xenon enriched in 136 Xe.

Purpose We analyzed the best performance times of master cycling athletes in the 200–3000 m track competitions to estimate the decay of maximal aerobic power (MAP) and anaerobic capacity (AnS) with aging. Methods In various decades of age (30–80 years), MAP and AnS were estimated using an iterative procedure as the values that minimize the difference between: (1) the metabolic power ( E ˙ t ) necessary to cover a given distance ( d ) in the time t and; (2) the maximal metabolic power ( E ˙ max t ) maintained at a constant level throughout the competition. Results MAP started decreasing at 45 years of age. Thereafter, it showed an average percent rate of decrease of about 16 % for decade, as previously shown in other classes of master athletes. In addition, AnS seemed to decay by about 11 % every 10 years from the second part of the fifth decade. Conclusions The decay of MAP occurred in spite of the active lifestyle of the subjects and it may be attributed to the progressive impairment of maximal O 2 delivery and/or of peripheral O 2 utilization. The loss of AnS might derive from the progressive loss of muscle mass occurring after the fifth decade of life, to the progressive qualitative deterioration of the anaerobic energy yielding pathways or to the lower capacity of MN recruitment during maximal efforts. The proposed approach may be applied to other types of human locomotion of whom the relationship between performance t and E ˙ t is known.

We compared two protocols for the expansion of human mesenchymal stromal cells (hMSCs) starting from diagnostic samples of BM aspirates (2-5 ml) or using the remnants in the bag and filter at the end of the BM infusions. The protocols differed in the presence of either 10% fetal bovine serum (FBS) or 5% platelet lysate (PL). We obtained a significantly (P=0.02) better expansion with PL, obtaining a median 1010-fold compared to 198-fold with a selected batch of FBS and in fewer days (29.8 in PL versus 41.4 in FBS). Overall, we recovered a variable number from 54.8 x 10(6) to 365 x 10(6) hMSCs in PL versus a variable number from 2.7 x 10(6) to 31 x 10(6) in FBS. No difference could be found in terms of gross morphology, differentiation potential, surface markers and immunological properties (inhibition of allogeneic PHA response and mixed lymphocyte reaction) of cells expanded with PL or FBS. The preparations were found within the range of acceptability for all the quality control criteria. Due to the clinical grade nature of the PL and the reproducibility of separate preparations, we propose this method to obtain hMSCs even from minute amounts of BM cells.

People with glycogen storage disease type III (GSDIII‐p) have a remarkably reduced exercise tolerance. Aim of this study was to analyze the oxygen transport‐utilization chain strategies adopted by GSDIII‐p during exercise. Nine GSDIII‐p (39.4 ± 10.0 year, 33% female) and 11 healthy controls (CTRL), age and gender matched, underwent an incremental cardiopulmonary exhaustion test (CPET) to assess peak heart rate (HR), blood lactate [La]p and vastus lateralis O 2 fractional extraction (ΔHHb/isch) using near‐infrared spectroscopy. Patterns of breathing (PBr) were assessed accordingly by analyzing pulmonary O 2 uptake (V̇O 2 ), tidal volume (Vt), respiratory frequency (Rf), end‐tidal CO 2 (PETCO 2 ) and alveolar ventilation (V̇A). GSDIII‐p exhibited significantly ( p < 0.05) lower peak values of V̇O 2 , pulmonary ventilation (V̇E) [La] and ΔHHb/isch compared to CTRL (1.7 ± 0.7 vs. 3.2 ± 1.1 L/min, 50.5 ± 19.8 vs. 113.6 ± 40.4 L/min, 1.8 ± 0.7 vs. 7.6 ± 3.0 mmol/L and 39.1% ± 9.9% vs. 74.8% ± 36.6%, respectively). The range of peak V̇O 2 values for GSDIII‐p, compared to the predicted values for age and sex, was between 79% and 35%. Both GSDIII‐p and CTRL were arbitrarily divided into 4 groups according to individual V̇E values. GSDIII‐p with exercise intolerance relied on increased Rf with inadequate Vt adaptation to maintain V̇E and reduce PETCO 2 , with low V̇A values and low to moderate workloads tolerance. Reduced exercise tolerance in GSDIII‐p is related to respiratory and skeletal muscle inefficiencies. GSDIII‐p strong heterogeneity evaluated throught CPET provides insights into clinical management.