3,628 research outputs found

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

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    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

    Comment on "Large energy gaps in CaC6 from tunneling spectroscopy: possible evidence of strong-coupling superconductivity"

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    Comment on "Large energy gaps in CaC6 from tunneling spectroscopy: possible evidence of strong-coupling superconductivity

    Sodium Channels as Targets for Volatile Anesthetics

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    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

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    We present scanning tunneling microscopy and spectroscopy of the newly discovered superconductor CaC6_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 Δ(0)\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 ξab\xi_{ab}\simeq 33 nm

    The Feasibility of Training Teachers to be More Humanistic and the Training's Effect on the Teachers' Students

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    vi, 82 leaves. Advisor: Edward E. HakansonThe problem. Research has indicated that human, person-centered characteristics in a classroom do make a difference. This study was concerned with the effects of a midwestern intermediate education agency's human relations training program. The study determined certain effects of this training on teachers and its transferability to the teachers' students in a midwestern school district. Procedures. Ten elementary teachers (five teachers in the control and experimental groups, respectively) were selected from a midwestern school district. The research design was a nonequivalent control group design. The five experimental teachers were selected from the group of elementary teachers who had registered for human relations training in the summer of 1978. The five control teachers were chosen from the group of elementary teachers not taking training. They were matched with the five in the experimental group by grade level, achievement of students in the last three years. and instructional setting. Data for the research study were collected by video tapes and achievement tests. Each teacher in the control and experimental groups was taped for one-half to one hour in the classroom as a pretest during May of 1978 and during April of 1979 as a posttest. The experimental group of teachers participated in forty-five hours of human relations training in June of 1978. In September of 1978, all students of the ten teachers were administered the Stanford Achievement Test. Data only from the subtests of Vocabulary, Reading Comprehension, and Word Study Skills were used. In April of 1979, the three subtests of the SAT were administered to the students of the ten teachers participating in this study. The video tapes were viewed and rated by professional, trained raters from the National Consortium for Humanizing Education. The raters used the Carkhuff Scales to assess the pretest and posttest video tapes of the ten teachers for empathy, congruence, and positive regard. The ruters also rated the responses and actions of the students in the ten classrooms on the Taxonomy of the Affective Domain by Krathwohl, Bloom and Masia (for both pretest and posttest video tapes). Findings. There were no significant differences between the mean gain score of "the experimental group of teachers and the mean gain score for the control group of teachers for each interpersonal functioning variable: empathy, congruence, and positive regard. Also, there were no significant differences between the mean gain score of the students of the experimental group of teachers and the mean gain score of the students of the control group of teachers for each of the subtests of SAT: Vocabulary. Reading Comprehension. and Word Study Skills. By looking at the percentages of responses and actions of the experimental students versus the control students on the Taxonomy of the Affective Domain, there appeared to be no major changes in responses up the affecti ve scale from preaasessment tapes to the postassessment tapes. Recommendations. Replicate the study utilizing other evaluative instruments which may more accurately reflect the effectiveness of the program. The number of research participants needs to be increased and randomly selected from a population in any further research on this topic. Research to determine the validity of the Carkhuff Scales in studies of this type should be carried out

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

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    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

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    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

    Interactive biocatalysis achieved by driving enzyme cascades inside a porous conducting material

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    An emerging concept and platform, the electrochemical Leaf (e-Leaf), offers a radical change in the way tandem (multi-step) catalysis by enzyme cascades is studied and exploited. The various enzymes are loaded into an electronically conducting porous material composed of metallic oxide nanoparticles, where they achieve high concentration and crowding – in the latter respect the environment resembles that found in living cells. By exploiting efficient electron tunneling between the nanoparticles and one of the enzymes, the e-Leaf enables the user to interact directly with complex networks, rendering simultaneous the abilities to energise, control and observe catalysis. Because dispersion of intermediates is physically suppressed, the output of the cascade – the rate of flow of chemical steps and information – is delivered in real time as electrical current. Myriad enzymes of all major classes now become effectively electroactive in a technology that offers scalability between micro-(analytical, multiplex) and macro-(synthesis) levels. This Perspective describes how the e-Leaf was discovered, the steps in its development so far, and the outlook for future research and applications

    Unstable states in QED of strong magnetic fields

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    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 SS-matrix elements with external unstable particles.Comment: Revtex, 7 pages. To appear in Phys. Rev. D53(2
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