4,617 research outputs found
Underground measurements on secondary cosmic rays
Measurements made at the Poatina cosmic ray station (41.8 S 149.9 E, 347 m.w.e.) from August 1983 to July 1984 are summarized. The cosmic ray primary particles responsible for events detected at the station have a median primary energy of 1.2 TeV. The motivation for part of this work came from the reported detection of narrow angle anisotropies in the arrival direction of cosmic rays
Remote sensing in Iowa agriculture: Identification and classification of Iowa's crops, soils and forestry resources using ERTS-1 and complimentary underflight imagery
The author has identified the following significant results. Springtime ERTS-1 imagery covering pre-selected test sites in Iowa showed considerable detail with respect to broad soil and land use patterns. Additional imagery has been incorporated into a state mosaic. The mosaic was used as a base for soil association lines transferred from an existing map. The regions of greatest contrast are between the Clarion-Nicollet-Webster soil association area and adjacent areas. Landscape characteristics in this area result in land use patterns with a high percentage of pasture, hay, and timber. The soil association areas of the state that have patterns interpreted to be associated with intensive row crop production are: Moody, Galva-Primghar-Sac, Clarion-Nicollet-Webter, Tama-Muscatine, Dinsdale-Tama, Cresco-Lourdes, Clyde, Kenyon-Floyd-Clyde, and the Luton-Onawa-Salix area on the Missouri River floodplain. Forestland estimates have been attained for an area in central Iowa using wintertime ERTS-1 imagery. Visual analysis of multispectral, temporal imagery indicates that temporal analysis for cropland identification and acreage analyses procedures may be a very useful tool. Combinations of wintertime, springtime, and summertime ERTS-1 imagery separate most vegetation types. Timing can be critical depending upon crop development and harvesting times because of the dynamic nature of agricultural production
Remote sensing in Iowa agriculture: Identification and classification of Iowa's crops, soils and forestry resources using ERTS-1 and complimentary underflight imagery
There are no author-identified significant results in this report
The thrombin receptor in adrenal medullary microvascular endothelial cells is negatively coupled to adenylyl cyclase through a Gi protein
AbstractThe effects of thrombin on adenylyl cyclase activity were examined in rat adrenal medullary microvascular endothelial cells (RAMEC). Confluent RAMEC monolayers were stimulated for 5 min with cAMP-generating agents in the absence and presence of thrombin, and intracellular cAMP was measured with a radioligand binding assay. Thrombin (0.001–0.25 U/ml) dose-dependently inhibited IBMX-, isoproterenol- and forskolin-stimulated cAMP accumulation. A peptide agonist of the thrombin receptor, γ-thrombin, and the serine proteases trypsin and plasmin, also inhibited agonist-stimulated cAMP levels, while proteolytically inactive PPACK- or DIP-α-thrombins were without effect. Moreover, the thrombin inhibitor hirudin abolished the inhibitory effect of thrombin but not of the peptide agonist. These results suggest that the inhibitory action of thrombin on cAMP accumulation is mediated by a proteolytically-activated thrombin receptor. The inhibitor of Gi-proteins pertussis toxin abolished the inhibitory effect of thrombin on isoproterenol- or IBMX-stimulated cAMP production, while the phorbol ester PMA partly impaired it. The protein kinase C inhibitors staurosporine or H7 and the intracellular Ca2+ chelator BAPTA-AM were without effect. Collectively, our data suggest that the thrombin receptor in RAMEC is negatively coupled to adenylyl cyclase through a pertussis toxin-sensitive Gi-protein
Iowan Drift Problem, Northeastern Iowa
https://ir.uiowa.edu/igs_ri/1006/thumbnail.jp
Nonlinear Magneto-Optical Response of - and -Wave Superconductors
The nonlinear magneto-optical response of - and -wave superconductors
is discussed. We carry out the symmetry analysis of the nonlinear
magneto-optical susceptibility in the superconducting state. Due to the surface
sensitivity of the nonlinear optical response for systems with bulk inversion
symmetry, we perform a group theoretical classification of the superconducting
order parameter close to a surface. For the first time, the mixing of singlet
and triplet pairing states induced by spin-orbit coupling is systematically
taken into account. We show that the interference of singlet and triplet
pairing states leads to an observable contribution of the nonlinear
magneto-optical Kerr effect. This effect is not only sensitive to the
anisotropy of the gap function but also to the symmetry itself. In view of the
current discussion of the order parameter symmetry of High-T
superconductors, results for a tetragonal system with bulk singlet pairing for
various pairing symmetries are discussed.Comment: 21 pages (REVTeX) with 8 figures (Postscript
Differences in client and therapist views of the working alliance in drug treatment
Background - There is growing evidence that the therapeutic alliance is one of the most consistent predictors of retention and outcomes in drug treatment. Recent psychotherapy research has indicated that there is a lack of agreement between client, therapist and observer ratings of the therapeutic alliance; however, the clinical implications of this lack of consensus have not been explored.
Aims - The aims of the study are to (1) explore the extent to which, in drug treatment, clients and counsellors agree in their perceptions of their alliance, and (2) investigate whether the degree of disagreement between clients and counsellors is related to retention in treatment.
Methods - The study recruited 187 clients starting residential rehabilitation treatment for drug misuse in three UK services. Client and counsellor ratings of the therapeutic alliance (using the WAI-S) were obtained during weeks 1-12. Retention was in this study defined as remaining in treatment for at least 12 weeks.
Results - Client and counsellor ratings of the alliance were only weakly related (correlations ranging from r = 0.07 to 0.42) and tended to become more dissimilar over the first 12 weeks in treatment. However, whether or not clients and counsellors agreed on the quality of their relationship did not influence whether clients were retained in treatment.
Conclusions - The low consensus between client and counsellor views of the alliance found in this and other studies highlights the need for drug counsellors to attend closely to their clients' perceptions of the alliance and to seek regular feedback from clients regarding their feelings about their therapeutic relationship
Electron and hole transmission through superconductor - normal metal interfaces
We have investigated the transmission of electrons and holes through
interfaces between superconducting aluminum (Tc = 1.2 K) and various normal
non-magnetic metals (copper, gold, palladium, platinum, and silver) using
Andreev-reflection spectroscopy at T = 0.1 K. We analyzed the point contacts
with the modified BTK theory that includes Dynes' lifetime as a fitting
parameter G in addition to superconducting energy gap 2D and normal reflection
described by Z. For contact areas from 1 nm^2 to 10000 nm^2 the BTK Z parameter
was 0.5, corresponding to transmission coefficients of about 80 %, independent
of the normal metal. The very small variation of Z indicates that the
interfaces have a negligible dielectric tunneling barrier. Fermi surface
mismatch does not account for the observed transmission coefficient.Comment: 9 pages, 4 figures, submitted to Proceedings of the 19th
International Conference on Magnetism ICM2012 (Busan 2012
Emergence of Quantum Phase-Slip Behaviour in Superconducting NbN Nanowires: DC Electrical Transport and Fabrication Technologies
Superconducting nanowires undergoing quantum phase-slips have potential for
impact in electronic devices, with a high-accuracy quantum current standard
among a possible toolbox of novel components. A key element of developing such
technologies is to understand the requirements for, and control the production
of, superconducting nanowires that undergo coherent quantum phase-slips. We
present three fabrication technologies, based on using electron-beam
lithography or neon focussed ion-beam lithography, for defining narrow
superconducting nanowires, and have used these to create nanowires in niobium
nitride with widths in the range of 20-250 nm. We present characterisation of
the nanowires using DC electrical transport at temperatures down to 300 mK. We
demonstrate that a range of different behaviours may be obtained in different
nanowires, including bulk-like superconducting properties with critical-current
features, the observation of phase-slip centres and the observation of zero
conductance below a critical voltage, characteristic of coherent quantum
phase-slips. We observe critical voltages up to 5 mV, an order of magnitude
larger than other reports to date. The different prominence of quantum
phase-slip effects in the various nanowires may be understood as arising from
the differing importance of quantum fluctuations. Control of the nanowire
properties will pave the way for routine fabrication of coherent quantum
phase-slip nanowire devices for technology applications.Comment: 14 pages, 8 figure
Approximate probabilistic verification of hybrid systems
Hybrid systems whose mode dynamics are governed by non-linear ordinary
differential equations (ODEs) are often a natural model for biological
processes. However such models are difficult to analyze. To address this, we
develop a probabilistic analysis method by approximating the mode transitions
as stochastic events. We assume that the probability of making a mode
transition is proportional to the measure of the set of pairs of time points
and value states at which the mode transition is enabled. To ensure a sound
mathematical basis, we impose a natural continuity property on the non-linear
ODEs. We also assume that the states of the system are observed at discrete
time points but that the mode transitions may take place at any time between
two successive discrete time points. This leads to a discrete time Markov chain
as a probabilistic approximation of the hybrid system. We then show that for
BLTL (bounded linear time temporal logic) specifications the hybrid system
meets a specification iff its Markov chain approximation meets the same
specification with probability . Based on this, we formulate a sequential
hypothesis testing procedure for verifying -approximately- that the Markov
chain meets a BLTL specification with high probability. Our case studies on
cardiac cell dynamics and the circadian rhythm indicate that our scheme can be
applied in a number of realistic settings
- …