Correction function in the Lidar equation and the solution techniques for CO2 Lidar date reduction

For lidar systems with long laser pulses the unusual behavior of the near-range signals causes serious difficulties and large errors in reduction. The commonly used lidar equation is no longer applicable since the convolution of the laser pulse with the atmospheric parameter distributions should be taken into account. It is important to give more insight into this problem and find the solution techniques. Starting from the original equation, a general form is suggested for the single scattering lidar equation where a correction function Cr is introduced. The correction Function Cr(R) derived from the original equation indicates the departure from the normal lidar equation. Examples of Cr(R) for a coaxial CO2 lidar system are presented. The Differential Absorption Lidar (DIAL) errors caused by the differences of Cr(R) for H2O measurements are plotted against height

Einstein Observatory solid state spectrometer observations of M87 and the Virgo cluster

X-ray observations of the galaxy M87 and of a region in the Virgo cluster displaced 7 minutes from the center of M87 are presented. X-ray spectra are obtained at these two locations with the slid state spectrometer onboard the Einstein Observatory. Emission lines were observed in both locations, indicating the presence of heavy elements at abundances approximately solar (to within a factor of 2). A temperature gradient, T increases from approximately 1.4 keV at the position of M87 to T approximately 3.35 keV 7' away, was detected. There is lower temperature thermal emission at the center of M87 with T approximately 0.6 keV, consistent with models for cooling flows in this cluster. In addition to the thermal emission, a power law component in the spectrum of M87, was detected consistent with that observed by HEAO-1, indicating that this component probably originates in the galaxy itself. The presence of intracluster gas having density approximately .001 cu cm and temperature approximately 30 million K is indicated

Evaluation of existing and new methods of tracking glacier terminus change

ACKNOWLEDGEMENTS The authors thank two anonymous reviewers for constructive comments that helped to improve the manuscript. This research was financially supported by J.M.L.’s PhD funding from UK Natural Environment Research Council grant No. NE/I528742/1.Peer reviewedPublisher PD

Research interventions to strengthen irrigators' associations

Irrigation management, Water distribution, Financing, Data collection, Operations, Maintenance, Performance indexes, Privatization, Farmer-agency interactions, Institution building, Farmers associations, Training, Participatory management, Leadership, Farm Management, Institutional and Behavioral Economics, Research and Development/Tech Change/Emerging Technologies, Teaching/Communication/Extension/Profession,

Reclaiming literacies: competing textual practices in a digital higher education

This essay examines the implications of the ubiquitous use of the term ‘digital literacies’ in higher education and its increasing alignment with institutional and organisational imperatives. It suggests that the term has been stripped of its provenance and association with disciplinary knowledge production and textual practice. Instead it is called into service rhetorically in order to promote competency based agendas both in and outside the academy. The piece also points to a tendency to position teachers in deficit with regard to their technological capabilities and pay scant attention to their own disciplinary and scholarly practices in a digital world. It concludes that there is a case for building on established theoretical and conceptual frameworks from literacy studies if we wish to integrate advantages of the digital landscape with thoughtful teaching practice

Fluctuations of a Greenlandic tidewater glacier driven by changes in atmospheric forcing : observations and modelling of Kangiata Nunaata Sermia, 1859–present

Acknowledgements. The authors wish to thank Stephen Price, Mauri Pelto, and the anonymous reviewer for their reviews and comments that helped to improve the manuscript. RACMO2.1 data were provided by Jan van Angelen and Michiel van den Broeke, IMAU, Utrecht University. MAR v3.2 data used for runoff calculations were provided by Xavier Fettweis, Department of Geography, University of Liège. The photogrammetric DEM used in Figs. 1 and 3 was provided by Kurt H. Kjær, Centre for GeoGenetics, University of Copenhagen. This research was financially supported by J. M. Lea’s PhD funding, NERC grant number NE/I528742/1. Support for F. M. Nick was provided through the Conoco-Phillips/Lundin Northern Area Program CRIOS project (Calving Rates and Impact on Sea Level).Peer reviewedPublisher PD

Analytical toxicology of yew constituents in human blood and urine by liquid chromatography-high-resolution tandem mass spectrometry

The active, poisonous constituents in Taxus baccata, the yew plants, are taxine alkaloids whose main action is suggested to be a block of calcium and sodium channels. The main alkaloids are taxine B (30%) and taxine A (1.3%). Symptoms can include bradycardia, bradypnea, diastolic, and cardiac standstill. The current investigation reports the analytical toxicology of human blood and urine to confirm a suspected ingestion of yew needles. This includes the qualitative detection of several yew ingredients, including the main alkaloids, the validated quantification of 3,5-dimethoxyphenol, and the discussion of suitable analytical targets. After analyzing human specimens and yew needle extracts using the developed procedures, the five alkaloids 1-deotaxine B, taxicatin, taxine A, taxine B, and taxine I could be detected and tentatively identified. Finally, taxine A and B can be recommended as analytical targets besides 3,5-dimethoxyphenol

Magneto-shear modes and a.c. dissipation in a two-dimensional Wigner crystal

The a.c. response of an unpinned and finite 2D Wigner crystal to electric fields at an angular frequency $\omega$ has been calculated in the dissipative limit, $\omega \tau \ll 1$, where $\tau ^{-1}$ is the scattering rate. For electrons screened by parallel electrodes, in zero magnetic field the long-wavelength excitations are a diffusive longitudinal transmission line mode and a diffusive shear mode. A magnetic field couples these modes together to form two new magneto-shear modes. The dimensionless coupling parameter $\beta =2(c_{t}/c_{l})|\sigma_{xy}/\sigma_{xx}|$ where $c_{t}$ and $c_{l}$ are the speeds of transverse and longitudinal sound in the collisionless limit and $\sigma_{xy}$ and $\sigma_{xx}$ are the tensor components of the magnetoconductivity. For $\beta \geqslant 1$, both the coupled modes contribute to the response of 2D electrons in a Corbino disk measurement of magnetoconductivity. For $\beta \gg 1$, the electron crystal rotates rigidly in a magnetic field. In general, both the amplitude and phase of the measured a.c. currents are changed by the shear modulus. In principle, both the magnetoconductivity and the shear modulus can be measured simultaneously.Comment: REVTeX, 7 pp., 4 eps figure

Recent trends in drugs of abuse metabolism studies for mass spectrometry-based analytical screening procedures

The still increasing number of drugs of abuse, particularly the so-called new psychoactive substances (NPS), poses an analytical challenge for clinical and forensic toxicologists but also for doping control. NPS usually belong to various classes such as synthetic cannabinoids, phenethylamines, opioids, or benzodiazepines. Like other xenobiotics, NPS undergo absorption, distribution, metabolism, and excretion processes after consumption, but only very limited data concerning their toxicokinetics and safety properties is available once they appear on the market. The inclusion of metabolites in mass spectral libraries is often crucial for the detection of NPS especially in urine screening approaches. Authentic human samples may represent the gold standard for identification of metabolites but are often not available and clinical studies cannot be performed due to ethical concerns. However, numerous alternative in vitro and in vivo models are available. This trends article will give an overview on selected models, discuss current studies, and highlight recent developments