Assessing satellite-derived land product quality for earth system science applications: results from the ceos lpv sub-group

The value of satellite derived land products for science applications and research is dependent upon the known accuracy of the data. CEOS (Committee on Earth Observation Satellites), the space arm of the Group on Earth Observations (GEO), plays a key role in coordinating the land product validation process. The Land Product Validation (LPV) sub-group of the CEOS Working Group on Calibration and Validation (WGCV) aims to address the challenges associated with the validation of global land products. This paper provides an overview of LPV sub-group focus area activities, which cover seven terrestrial Essential Climate Variables (ECVs). The contribution will enhance coordination of the scientific needs of the Earth system communities with global LPV activities

Sodium Channels as Targets for Volatile Anesthetics

The molecular mechanisms of modern inhaled anesthetics are still poorly understood although they are widely used in clinical settings. Considerable evidence supports effects on membrane proteins including ligand- and voltage-gated ion channels of excitable cells. Na+ channels are crucial to action potential initiation and propagation, and represent potential targets for volatile anesthetic effects on central nervous system depression. Inhibition of presynaptic Na+ channels leads to reduced neurotransmitter release at the synapse and could therefore contribute to the mechanisms by which volatile anesthetics produce their characteristic end points: amnesia, unconsciousness, and immobility. Early studies on crayfish and squid giant axon showed inhibition of Na+ currents by volatile anesthetics at high concentrations. Subsequent studies using native neuronal preparations and heterologous expression systems with various mammalian Na+ channel isoforms implicated inhibition of presynaptic Na+ channels in anesthetic actions at clinical concentrations. Volatile anesthetics reduce peak Na+ current (INa) and shift the voltage of half-maximal steady-state inactivation (h∞) toward more negative potentials, thus stabilizing the fast-inactivated state. Furthermore recovery from fast-inactivation is slowed, together with enhanced use-dependent block during pulse train protocols. These effects can depress presynaptic excitability, depolarization and Ca2+ entry, and ultimately reduce transmitter release. This reduction in transmitter release is more potent for glutamatergic compared to GABAergic terminals. Involvement of Na+ channel inhibition in mediating the immobility caused by volatile anesthetics has been demonstrated in animal studies, in which intrathecal infusion of the Na+ channel blocker tetrodotoxin increases volatile anesthetic potency, whereas infusion of the Na+ channels agonist veratridine reduces anesthetic potency. These studies indicate that inhibition of presynaptic Na+ channels by volatile anesthetics is involved in mediating some of their effects

Scanning Tunneling Spectroscopy on the novel superconductor CaC6

We present scanning tunneling microscopy and spectroscopy of the newly discovered superconductor CaC$_6$. The tunneling conductance spectra, measured between 3 K and 15 K, show a clear superconducting gap in the quasiparticle density of states. The gap function extracted from the spectra is in good agreement with the conventional BCS theory with $\Delta(0)$ = 1.6 $\pm$ 0.2 meV. The possibility of gap anisotropy and two-gap superconductivity is also discussed. In a magnetic field, direct imaging of the vortices allows to deduce a coherence length in the ab plane $\xi_{ab}\simeq$ 33 nm

Editorial DEPP: drug experienced young people in contact with the criminal justice system. Understanding the challenges and working towards solutions

The focus of this collection of papers is on young people (age 14–25) who are drug experienced and are in contact with the Criminal Justice System (CJS). In general, research tends to focus on either young people’s drug use or offending; equally, we see a tendency within policy and service responses to focus on interventions aimed either at drug use or at offending but rarely addressing complex problems that may include drug use and offending (Herold et al., 2019). By drawing on young peoples’ own perspectives and experiences and focusing on multiple problem areas at the same time, this collection presents findings that complement and augment the existing literature, and are highly relevant to policy development and service provision by: providing an account of young people’s own perspectives and experiences of their drug use and offending trajectories and the experienced relationship between these trajectories; describing young people’s own perspectives and experiences of different kinds of drug and/or offending reducing initiatives they have participated in and what they appreciate and/or find difficult in these institutional arrangements; showing how professionals engage with this group of young people, and how young people themselves consider engagement in services offered to them; and finally, highlighting the unintended consequences for and experienced by young people of the application of prohibitive drug policies and of involvement in the criminal justice system

Downscaling stream flow time series from monthly to daily scales using an auto-regressive stochastic algorithm: StreamFARM

Downscaling methods are used to derive stream flow at a high temporal resolution from a data series that has a coarser time resolution. These algorithms are useful for many applications, such as water management and statistical analysis, because in many cases stream flow time series are available with coarse temporal steps (monthly), especially when considering historical data; however, in many cases, data that have a finer temporal resolution are needed (daily). In this study, we considered a simple but efficient stochastic auto-regressive model that is able to downscale the available stream flow data from monthly to daily time resolution and applied it to a large dataset that covered the entire North and Central American continent. Basins with different drainage areas and different hydro-climatic characteristics were considered, and the results show the general good ability of the analysed model to downscale monthly stream flows to daily stream flows, especially regarding the reproduction of the annual maxima. If the performance in terms of the reproduction of hydrographs and duration curves is considered, better results are obtained for those cases in which the hydrologic regime is such that the annual maxima stream flow show low or medium variability, which means that they have a low or medium coefficient of variation; however, when the variability increases, the performance of the model decreases

Unstable states in QED of strong magnetic fields

We question the use of stable asymptotic scattering states in QED of strong magnetic fields. To correctly describe excited Landau states and photons above the pair creation threshold the asymptotic fields are chosen as generalized Licht fields. In this way the off-shell behavior of unstable particles is automatically taken into account, and the resonant divergences that occur in scattering cross sections in the presence of a strong external magnetic field are avoided. While in a limiting case the conventional electron propagator with Breit-Wigner form is obtained, in this formalism it is also possible to calculate $S$-matrix elements with external unstable particles.Comment: Revtex, 7 pages. To appear in Phys. Rev. D53(2

Vibroakustische Sensorik zur aktiven Minimierung der Schallab strahlung schwingender Strukturen

Für die Entwicklung adaptiver Struktursysteme, die u.a. auf die akustische Verbesserung von Bauteilen abzielen, ist die Kenntnis des Zusammenhangs zwischen dem dynamischen Verhalten und dem dadurch induzierten Luftschallfeld notwendig. In den vergangenen Jahren wurden zahlreiche Untersuchungen zur Ermittlung dieses Zusammenhangs durchgeführt. Eine notwendige Bedingung für die Realisierung eines adaptiven vibroakustischen Systems ist die sensorische Erfassung des entstehenden Luftschallfeldes anhand strukturdynamischer Messgrößen. Da die globale Erfassung der abgestrahlten Schallleistung konventionell nur mit externen Messwertaufnehmern möglich ist (z.B. Mikrophone, Schallintensitätssonden) und sich eine solche technische Lösung nur mit sehr hohem Aufwand realisieren lässt, soll hier ein Ansatz vorgestellt werden, der auf strukturapplizierte Sensoren zur Ermittlung der globalen Schallabstrahlung schwingender Strukturen abzielt. Als Sensoren werden piezokeramische Plättchen (PZT-Patches) eingesetzt. Als Maß für die abgestrahlte Schallleistung wird die Volumengeschwindigkeit verwendet, die aus den Sensorsignalen der Patches rekonstruiert wird. Somit entfallen aufwendige akustische Messungen. Ein weiteres Ziel der Arbeit ist die Integration der rekonstruierten Zielfunktion in einen adaptiven Regelkreis