Some applications of radar return data to the study of terrestrial and oceanic phenomena

Side-looking radar spacecraft application to mapping, imagery, altimetry, geology, pedology, glaciology, agriculture, and oceanograph

Why the lowest Landau level approximation works in strongly type II superconductors

Higher than the lowest Landau level contributions to magnetization and specific heat of superconductors are calculated using Ginzburg - Landau equations approach. Corrections to the excitation spectrum around solution of these equations (treated perturbatively) are found. Due to symmetries of the problem leading to numerous cancellations the range of validity of the LLL approximation in mean field is much wider then a naive range and extends all the way down to $H = {H_{c2}(T)}/13$. Moreover the contribution of higher Landau levels is significantly smaller compared to LLL than expected naively. We show that like the LLL part the lattice excitation spectrum at small quasimomenta is softer than that of usual acoustic phonons. This enhanses the effect of fluctuations. The mean field calculation extends to third order, while the fluctuation contribution due to HLL is to one loop. This complements the earlier calculation of the LLL part to two loop order.Comment: 20 pages, Latex file, three figure

Western Juniper Field Guide: Asking the Right Questions to Select Appropriate Management Actions

Strong evidence indicates that western juniper has significantly expanded its range since the late 1800s by encroaching into landscapes once dominated by shrubs and herbaceous vegetation (fig. 1). Woodland expansion affects soil resources, plant community structure and composition, water, nutrient and fire cycles, forage production, wildlife habitat, and biodiversity. Goals of juniper management include an attempt to restore ecosystem function and a more balanced plant community that includes shrubs, grasses, and forbs, and to increase ecosystem resilience to disturbances. Developing a management strategy can be a difficult task due to uncertainty about how vegetation, soils, hydrologic function, and wildlife will respond to treatments. When developing a management strategy, the first and possibly most important step towards success is asking the right questions. Identifying the attributes of the area to be treated and selecting the right treatments to be applied are of utmost importance. One must ask questions addressing the kind of site (that is, potential natural vegetation, soils, etc.), the current state of the site (that is, successional, hydrologic, etc.), what components need to be restored, how the management unit fits in with the overall landscape mosaic, and the long-term goals and objectives for the area or region. Keep in mind sagebrush-steppe vegetation is dynamic and management strategies must take into account multi-decade time frames. This guide provides a set of tools that will help field biologists, land managers, and private landowners conduct rapid qualitative field assessments that address the kind of site and its current state. These tools include a list of questions to be addressed and a series of photographs, keys, tables, and figures to help evaluate a site. Conducting this assessment will help prioritize sites to be treated, select the best treatment, and predict outcomes. Success of a juniper management program may be greatly enhanced if an interdisciplinary team of local managers and resource specialists, who are experienced with vegetation, fuels, soils, hydrology, wildlife, and economic and sociological aspects of the local resource, use this guide to aid their decision-making

Historical-institutionalist perspectives on the development of the EU budget system

The EU budget has only recently started to feature in theories of European integration. Studies typically adopt a historical-institutionalist framework, exploring notions such as path dependency. They have, however, generally been rather aggregated, or coarse-grained, in their approach. The EU budget has thus been treated as a single entity rather than a series of inter-linked institutions. This paper seeks to address these lacunae by adopting a fine-grained approach. This enables us to emphasize the connections that exist between EU budgetary institutions, in both time and space. We show that the initial set of budgetary institutions was unable, over time, to achieve consistently their treaty-based objectives. In response, rather than reform these institutions at potentially high political cost, additional institutions were layered on top of the extant structures. We thus demonstrate how some EU budgetary institutions have remained unchanged, whilst others have been added or changed over time

Current-voltage characteristics of the two-dimensional XY model with Monte Carlo dynamics

Current-voltage characteristics and the linear resistance of the two-dimensional XY model with and without external uniform current driving are studied by Monte Carlo simulations. We apply the standard finite-size scaling analysis to get the dynamic critical exponent $z$ at various temperatures. From the comparison with the resistively-shunted junction dynamics, it is concluded that $z$ is universal in the sense that it does not depend on details of dynamics. This comparison also leads to the quantification of the time in the Monte Carlo dynamic simulation.Comment: 5 pages in two columns including 5 figures, to appear in PR

Evidence for Kosterlitz-Thouless type orientational ordering of CF3_3Br monolayers physisorbed on graphite

Monolayers of the halomethane CF$_3$Br adsorbed on graphite have been investigated by x-ray diffraction. The layers crystallize in a commensurate triangular lattice. On cooling they approach a three-sublattice antiferroelectric pattern of the in-plane components of the dipole moments. The ordering is not consistent with a conventional phase transition, but points to Kosterlitz-Thouless behavior. It is argued that the transition is described by a 6-state clock model on a triangular lattice with antiferromagnetic nearest neighbor interactions which is studied with Monte-Carlo simulations. A finite-size scaling analysis shows that the ordering transition is indeed in the KT universality class.Comment: 4 pages, 5 figure

Bioactivity and structural properties of chimeric analogs of the starfish SALMFamide neuropeptides S1 and S2

The starfish SALMFamide neuropeptides S1 (GFNSALMFamide) and S2 (SGPYSFNSGLTFamide) are the prototypical members of a family of neuropeptides that act as muscle relaxants in echinoderms. Comparison of the bioactivity of S1 and S2 as muscle relaxants has revealed that S2 is ten times more potent than S1. Here we investigated a structural basis for this difference in potency by comparing the bioactivity and solution conformations (using NMR and CD spectroscopy) of S1 and S2 with three chimeric analogs of these peptides. A peptide comprising S1 with the addition of S2's N-terminal tetrapeptide (Long S1 or LS1; SGPYGFNSALMFamide) was not significantly different to S1 in its bioactivity and did not exhibit concentration-dependent structuring seen with S2. An analog of S1with its penultimate residue substituted from S2 (S1(T); GFNSALTFamide) exhibited S1-like bioactivity and structure. However, an analog of S2 with its penultimate residue substituted from S1 (S2(M); SGPYSFNSGLMFamide) exhibited loss of S2-type bioactivity and structural properties. Collectively, our data indicate that the C-terminal regions of S1 and S2 are the key determinants of their differing bioactivity. However, the N-terminal region of S2 may influence its bioactivity by conferring structural stability in solution. Thus, analysis of chimeric SALMFamides has revealed how neuropeptide bioactivity is determined by a complex interplay of sequence and conformation

Dynamic scaling for 2D superconductors, Josephson junction arrays and superfluids

The value of the dynamic critical exponent $z$ is studied for two-dimensional superconducting, superfluid, and Josephson Junction array systems in zero magnetic field via the Fisher-Fisher-Huse dynamic scaling. We find $z\simeq5.6\pm0.3$, a relatively large value indicative of non-diffusive dynamics. Universality of the scaling function is tested and confirmed for the thinnest samples. We discuss the validity of the dynamic scaling analysis as well as the previous studies of the Kosterlitz-Thouless-Berezinskii transition in these systems, the results of which seem to be consistent with simple diffusion ($z=2$). Further studies are discussed and encouraged.Comment: 19 pages in two-column RevTex, 8 embedded EPS figure

NMR and NQR Fluctuation Effects in Layered Superconductors

We study the effect of thermal fluctuations of the s-wave order parameter of a quasi two dimensional superconductor on the nuclear spin relaxation rate near the transition temperature Tc. We consider both the effects of the amplitude fluctuations and the Berezinskii-Kosterlitz-Thouless (BKT) phase fluctuations in weakly coupled layered superconductors. In the treatment of the amplitude fluctuations we employ the Gaussian approximation and evaluate the longitudinal relaxation rate 1/T1 for a clean s-wave superconductor, with and without pair breaking effects, using the static pair fluctuation propagator D. The increase in 1/T1 due to pair breaking in D is overcompensated by the decrease arising from the single particle Green's functions. The result is a strong effect on 1/T1 for even a small amount of pair breaking. The phase fluctuations are described in terms of dynamical BKT excitations in the form of pancake vortex-antivortex (VA) pairs. We calculate the effect of the magnetic field fluctuations caused by the translational motion of VA excitations on 1/T1 and on the transverse relaxation rate 1/T2 on both sides of the BKT transitation temperature T(BKT)<Tc. The results for the NQR relaxation rates depend strongly on the diffusion constant that governs the motion of free and bound vortices as well as the annihilation of VA pairs. We discuss the relaxation rates for real multilayer systems where the diffusion constant can be small and thus increase the lifetime of a VA pair, leading to an enhancement of the rates. We also discuss in some detail the experimental feasibility of observing the effects of amplitude fluctuations in layered s-wave superconductors such as the dichalcogenides and the effects of phase fluctuations in s- or d-wave superconductors such as the layered cuprates.Comment: 38 pages, 12 figure

Immune System Dysregulation and Herpesvirus Reactivation Persist During Long-Duration Spaceflight

Background: Immunity, latent herpesvirus reactivation, physiological stress and circadian rhythms were assessed during six month spaceflight onboard ISS. Blood and saliva samples were collected early, mid and late in-flight and returned for immediate analysis. Mid-point study data (10 of 17 planned subjects) will be presented. Results: Some shifts in leukocyte distribution occurred during flight, including alterations in CD8+ T cell maturation. General T cell function was consistently reduced early in-flight. Levels CD8+/IFNg+ producing T cells were depressed early in-flight, and immediately upon landing. Persistent mitogen-dependant reductions were observed in IFNg, IL-17a, IL-10, TNFa and IL-6 production. Monocyte production of IL-10 was reduced, whereas IL-8 levels were increased. Levels of mRNA for the TNFa, IL-6 and IFNg were transiently elevated early in-flight, and the dynamics of TNF and IL-6 gene expression were somewhat antagonistic to their corresponding receptors during flight. The number of virus-specific CD8+ T-cells was measured using MHC tetramers, while their function was measured using intracellular cytokine analysis following peptide stimulation. Both the number and function of EBV-specific cells decreased during flight as compared to preflight levels. The number of CMV-specific T-cells generally increased as the mission progressed while their function was variable. Viral (EBV) load in blood was elevated postflight. Anti-EBV VCA antibodies were significantly elevated by R+0; anti-EA antibodies were not significantly elevated at landing; and anti-CMV antibodies were somewhat elevated during flight. Higher levels of salivary EBV DNA were found during flight. VZV DNA reactivation occurred in ~50 % of astronauts during flight, continuing for up to 30 days post-flight. CMV was shed in 35 % the in-flight and 30% of postflight urine samples of the crewmembers. There was generally a higher level of cortisol as measured in urine and saliva in the astronauts during flight, but plasma cortisol was relatively unchanged during flight. Circadian rhythm of salivary cortisol was altered during flight. Conclusion. Some alterations in immunity do not resolve during six month spaceflight, consequentially resulting in persistent herpesvirus reactivation. Ongoing immune dysregulation may represent specific clinical risks for exploration-class space missions