• Canada
• IT close
• CNR ExploRA close

Aim Species-area relationships (SARs) are fundamental scaling laws in ecology although their shape is still disputed. At larger areas, power laws best represent SARs. Yet, it remains unclear whether SARs follow other shapes at finer spatial grains in continuous vegetation. We asked which function describes SARs best at small grains and explored how sampling methodology or the environment influence SAR shape. Location Palaearctic grasslands and other non-forested habitats. Taxa Vascular plants, bryophytes and lichens. Methods We used the GrassPlot database, containing standardized vegetation-plot data from vascular plants, bryophytes and lichens spanning a wide range of grassland types throughout the Palaearctic and including 2,057 nested-plot series with at least seven grain sizes ranging from 1 cm(2) to 1,024 m(2). Using nonlinear regression, we assessed the appropriateness of different SAR functions (power, power quadratic, power breakpoint, logarithmic, Michaelis-Menten). Based on AICc, we tested whether the ranking of functions differed among taxonomic groups, methodological settings, biomes or vegetation types. Results The power function was the most suitable function across the studied taxonomic groups. The superiority of this function increased from lichens to bryophytes to vascular plants to all three taxonomic groups together. The sampling method was highly influential as rooted presence sampling decreased the performance of the power function. By contrast, biome and vegetation type had practically no influence on the superiority of the power law. Main conclusions We conclude that SARs of sessile organisms at smaller spatial grains are best approximated by a power function. This coincides with several other comprehensive studies of SARs at different grain sizes and for different taxa, thus supporting the general appropriateness of the power function for modelling species diversity over a wide range of grain sizes. The poor performance of the Michaelis-Menten function demonstrates that richness within plant communities generally does not approach any saturation, thus calling into question the concept of minimal area. We thank all vegetation scientists who carefully collected multi‐ scale plant diversity data from Palaearctic Grasslands available in GrassPlot. The Eurasian Dry Grassland Group (EDGG) and the International Association for Vegetation Science (IAVS) sup‐ ported the EDGG Field Workshops, which generated a core part of the GrassPlot data. The Bavarian Research Alliance (grant BayIntAn_UBT_2017_58) and the Bayreuth Center of Ecology and Environmental Research (BayCEER) funded the initial GrassPlot workshop during which the database was established and the cur‐ rent paper was initiated. A.N. acknowledges support by the Center for International Scientific Studies and Collaboration (CISSC), Iran. C.M., I.B., I.G.‐M and J.A.C. were funded by the Basque Government (IT936‐16). D.V. carried out the research supported by a grant of the State Fund For Fundamental Research Ф83/53427. G.F. carried out the research in the frame of the MIUR initiative ‘Department of excellence' (Law 232/2016). I.D. was supported by the Polish National Science Centre (grant DEC‐2013/09/N/NZ8/03234). J.Do. was supported by the Czech Science Foundation (GA 17‐19376S). M.J. was supported by grant by Slovak Academy of Sciences (VEGA 02/0095/19). W.U. ac‐ knowledges support from the Polish National Science Centre (grant 2017/27/B/NZ8/00316).

Charge transport in organic semiconductors is notoriously extremely sensitive to the presence of disorder, both internal and external (i.e. related to the interactions with the dielectric layer), especially for n-type materials. Internal dynamic disorder stems from large thermal fluctuations both in intermolecular transfer integrals and (molecular) site energies in weakly interacting van der Waals solids and sources transient localization of the charge carriers. The molecular vibrations that drive transient localization typically operate at low-frequency (< a-few-hundred cm-1), which renders it difficult to assess them experimentally. Hitherto, this has prevented the identification of clear molecular design rules to control and reduce dynamic disorder. In addition, the disorder can also be external, being controlled by the gate insulator dielectric properties. Here we report on a comprehensive study of charge transport in two closely related n-type molecular organic semiconductors using a combination of temperature-dependent inelastic neutron scattering and photoelectron spectroscopy corroborated by electrical measurements, theory and simulations. We provide unambiguous evidence that ad hoc molecular design enables to free the electron charge carriers from both internal and external disorder to ultimately reach band-like electron transport. arXiv admin note: text overlap with arXiv:1909.05344

We report on an all-sky search for continuous gravitational waves in the frequency band 20-2000 Hz and with a frequency time derivative in the range of [-1.0,+0.1]×10-8 Hz/s. Such a signal could be produced by a nearby, spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. This search uses the LIGO data from the first six months of Advanced LIGO's and Advanced Virgo's third observational run, O3. No periodic gravitational wave signals are observed, and 95% confidence-level (C.L.) frequentist upper limits are placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude h0 are ∼1.7×10-25 near 200 Hz. For a circularly polarized source (most favorable orientation), the lowest upper limits are ∼6.3×10-26. These strict frequentist upper limits refer to all sky locations and the entire range of frequency derivative values. For a population-averaged ensemble of sky locations and stellar orientations, the lowest 95% C.L. upper limits on the strain amplitude are ∼1.4×10-25. These upper limits improve upon our previously published all-sky results, with the greatest improvement (factor of ∼2) seen at higher frequencies, in part because quantum squeezing has dramatically improved the detector noise level relative to the second observational run, O2. These limits are the most constraining to date over most of the parameter space searched. This work was supported by MEXT, JSPS Leading-edge Research Infrastructure Program, JSPS Grant-in-Aid for Specially Promoted Research 26000005, JSPS Grant-in-Aid for Scientific Research on Innovative Areas 2905: JP17H06358, JP17H06361 and JP17H06364, JSPS Core-to-Core Program A. Advanced Research Networks, JSPS Grant-in-Aid for Scientific Research (S) 17H06133, the joint research program of the Institute for Cosmic Ray Research, University of Tokyo, National Research Foundation (NRF) and Computing Infrastructure Project of KISTI-GSDC in Korea, Academia Sinica (AS), AS Grid Center (ASGC) and the Ministry of Science and Technology (MoST) in Taiwan under grants including ASCDA-105-M06, Advanced Technology Center (ATC) of NAOJ, and Mechanical Engineering Center of KEK Abbott, R. (LIGO Scientific Collaboration, Virgo Collaboration, KAGRA Collaboration)

Abstract S -Nitrosoglutathione (GSNO) reacts with the organic mercurial probe, p -hydroxymercury benzoate (PHMB, HO–Hg–(C 6 H 4 )–COO − Na + ) giving the complex GS–Hg(C 6 H 4 )COOH (GS–PHMB). This reaction has been studied by UV measurements at 334 nm also in the presence of ascorbic acid and the product of reaction, the GS–PHMB complex, characterized by Electrospray Ionization Mass Spectrometry (ESI-MS) and by Reversed Phase Chromatography (RPLC) coupled on-line and sequentially with a UV–visible diode array detector (DAD) followed by a cold vapor generation atomic fluorescence spectrometer (CVGAFS). The simultaneous presence of PHMB and ascorbate produced a synergistic effect on GSNO decomposition rate that can be observed only above a given concentration threshold of ascorbate (ascorbate/GSNO molar ratio ≥ 180). The results indicated that the formation of GS–PHMB, both in the presence and the absence of ascorbic acid, does not involve the formation of free thiolic species but it takes place through a more complex mechanism. The PHMB derivatives of GSH and GSNO obtained by the present method were found to be identical by ESI-MS. GSSG did not interfere because it was not reduced and derivatized to GS–PHMB. Once complexed by the alkylating agent N -ethylmaleimide (NEM), GSH did not interfere with the derivatization reaction. This ensured a good selectivity of the developed PHMB derivatization system for RSNO determination. Thus, we have optimized the operating conditions for the selective reaction of PHMB with GSNO and other nitrosothiols (RSNOs) in order to determinate RSNOs in human plasma. LODc for RSNOs in plasma ultrafiltrate was 30 nM (injected concentration, 50 μL loop), the DLR ranged between 0.08 and 50 μM and the CV% was 6.5% at 300 nM concentration level. Reduced and oxidized thiols spiked to plasma did not interfere with the measurement of RSNOs. We found that the sampling procedure was critical for the recovery of endogenous and spiked RSNOs. The ultrafiltrate samples of plasma of 8 healthy humans contained 1460 ± 310 CysNO, 1000 ± 330 nM HCysNO and 320 ± 60 nM GSNO if blood was sampled in a mixture NEM/ethylendiaminotetracetic acid (EDTA)/serine–borate complex (SBC), where serine–borate complex is a potent inhibitor of γ-glutamyltransferase, an enzyme involved in the conversion of GSNO into CysGlyNO. In the absence of SBC during the sampling of blood GSNO concentration found in the ultrafiltrate was lower (at level of the determination limit in plasma ultrafiltrate, i.e. 75 nM) and the peak of CysGlyNO appeared, which corresponded to a concentration of 200 ± 60 nM ( N = 4 blood samples).

We report a novel design for an integrated optical parametric oscillator (OPO) in a CMOS-compatible microring. It exploits self-sustained lasing of the pump tuned to a microcavity resonance, preventing the OPO from dimming with thermal fluctuations.

Mass spectra of fully and partially deuterated As, Sb, Bi, Ge, and Sn hydrides have been obtained using several mathematical approaches aimed at signal extraction and reconstruction. Study of such hydride mixtures is important for the elucidation of hydride generation mechanisms. In this approach, mass spectra of partially deuterated isotopomers, i.e., AsH2D and AsHD2, are extracted using the weighted two-band target entropy minimization method. Alternatively, these mass spectra were constructed from the mass spectra of fully deuterated and hydrogenated hydrides using the statistical approach in fragmentation pathways. Concentration profiles of all deuterated hydrides were obtained from their overlapping mixture mass spectra using least-squares deconvolution.

Evolving new technologies in vascular access mandate increased attention to patient safety; an often overlooked yet valuable training tool is simulation. For the end-stage renal disease patient, simulation tools are effective for all aspects of creating access for peritoneal dialysis and hemodialysis. Based on aviation principles, known as crew resource management, we place equal emphasis on team training as individual training to improve interactions between team members and systems, cumulating in improved safety. Simulation allows for environmental control and standardized procedures, letting the trainee practice and correct mistakes without harm to patients, compared with traditional patient-based training. Vascular access simulators range from suture devices, to pressurized tunneled conduits for needle cannulation, to computer-based interventional simulators. Simulation training includes simulated case learning, root cause analysis of adverse outcomes, and continual update and refinement of concepts. Implementation of effective human to complex systems interaction in end-stage renal disease patients involves a change in institutional culture. Three concepts discussed in this article are as follows: (1) the need for user-friendly systems and technology to enhance performance, (2) the necessity for members to both train and work together as a team, and (3) the team assigned to use the system must test and practice it to a proficient level before safely using the system on patients.

In Photosystem I, the backbone nitrogen of Leu722 PsaA forms a hydrogen bond with the C 4 carbonyl oxygen of phylloquinone in the A 1A site. A previous low-temperature EPR study indicated that substitution of Leu722 PsaA with a bulky Trp residue results in a weakened H-bond. Here, we employ room temperature, time-resolved optical spectroscopy and variable temperature, transient EPR spectroscopy to probe the effect of the altered H-bond on the energetics and kinetics of electron transfer. Relative to the wild type, we find that the rate of electron transfer from A 1A - to F x in the L722W PsaA variant is faster by a factor of 3. This change is attributed to a lowered midpoint potential of A 1A /A 1A - , resulting in a larger Gibbs free energy change between A 1A /A 1A - andF x /F x - . An activation energy of 180 ± 10 meV is determined for the A 1A - -to-F x forward electron transfer step in the L722W PsaA variant compared with 220 ± 10 meV in the wild type. The Arrhenius plot shows a break at ~200 K, below which the rate becomes nearly independent of temperature. This behavior is described using a quantum mechanical treatment that takes the zero-point energy into account as well as an alternative model that invokes a dynamical transition in the protein at ~200 K.

Protecting osmolytes play a crucial role in preventing protein denaturation in harsh environmental conditions of living organisms. Experimental evidence is provided for a mechanism of protein-fold stabilization by these molecules that is in accord with the hypothesis of a backbone-based osmophobic effect. (In picture: ”G=free energy, [O]=osmolyte concentration, Ç=unfolding reaction coordinate.)

The Internet of Things is expected to generate an unprecedented number of unbounded data streams that will produce a paradigm shift when it comes to data analytics. We are moving away from performing analytics in a public or private cloud to performing analytics locally at the fog and edge resources. In this paper, we propose a network of tasks utilizing edge, fog, and cloud computing that are designed to support an Analytics Everywhere framework. The aim is to integrate a variety of computational resources and analytical capabilities according to a data life-cycle. We demonstrate the proposed framework using an application in smart transit.