Multispectral thermal imaging

Many remote sensing applications rely on imaging spectrometry. Here the authors use imaging spectrometry for thermal and multispectral signatures measured from a satellite platform enhanced with a combination of accurate calibrations and on-board data for correcting atmospheric distortions. The approach is supported by physics-based end-to-end modeling and analysis, which permits a cost-effective balance between various hardware and software aspects. The goal is to develop and demonstrate advanced technologies and analysis tools toward meeting the needs of the customer; at the same time, the attributes of this system can address other applications in such areas as environmental change, agriculture, and volcanology

Mining metrics for buried treasure

The same but different: That might describe two metrics. On the surface CLASSI may show two metrics are locally equivalent, but buried beneath one may be a wealth of further structure. This was beautifully described in a paper by M.A.H. MacCallum in 1998. Here I will illustrate the effect with two flat metrics -- one describing ordinary Minkowski spacetime and the other describing a three-parameter family of Gal'tsov-Letelier-Tod spacetimes. I will dig out the beautiful hidden classical singularity structure of the latter (a structure first noticed by Tod in 1994) and then show how quantum considerations can illuminate the riches. I will then discuss how quantum structure can help us understand classical singularities and metric parameters in a variety of exact solutions mined from the Exact Solutions book.Comment: 16 pages, no figures, minor grammatical changes, submitted to Proceedings of the Malcolm@60 Conference (London, July 2004

Scaling anomaly in cosmic string background

We show that the classical scale symmetry of a particle moving in cosmic string background is broken upon inequivalent quantization of the classical system, leading to anomaly. The consequence of this anomaly is the formation of single bound state in the coupling interval \gamma\in(-1,1). The inequivalent quantization is characterized by a 1-parameter family of self-adjoint extension parameter \omega. It has been conjectured that the formation of loosely bound state in cosmic string background may lead to the so called anomalous scattering cross section for the particles, which is usually seen in molecular physics.Comment: 4 pages,1 figur

Crises and collective socio-economic phenomena: simple models and challenges

Financial and economic history is strewn with bubbles and crashes, booms and busts, crises and upheavals of all sorts. Understanding the origin of these events is arguably one of the most important problems in economic theory. In this paper, we review recent efforts to include heterogeneities and interactions in models of decision. We argue that the Random Field Ising model (RFIM) indeed provides a unifying framework to account for many collective socio-economic phenomena that lead to sudden ruptures and crises. We discuss different models that can capture potentially destabilising self-referential feedback loops, induced either by herding, i.e. reference to peers, or trending, i.e. reference to the past, and account for some of the phenomenology missing in the standard models. We discuss some empirically testable predictions of these models, for example robust signatures of RFIM-like herding effects, or the logarithmic decay of spatial correlations of voting patterns. One of the most striking result, inspired by statistical physics methods, is that Adam Smith's invisible hand can badly fail at solving simple coordination problems. We also insist on the issue of time-scales, that can be extremely long in some cases, and prevent socially optimal equilibria to be reached. As a theoretical challenge, the study of so-called "detailed-balance" violating decision rules is needed to decide whether conclusions based on current models (that all assume detailed-balance) are indeed robust and generic.Comment: Review paper accepted for a special issue of J Stat Phys; several minor improvements along reviewers' comment

β Decay and isomeric properties of neutron-rich Ca and Sc isotopes

The isomeric and β-decay properties of neutron-rich Sc53-57 and Ca53,54 nuclei near neutron number N=32 are reported, and the low-energy level schemes of Sc53,54,56 and Ti53-57 are presented. The low-energy level structures of the 21Sc isotopes are discussed in terms of the coupling of the valence 1f7/2 proton to states in the corresponding 20Ca cores. Implications with respect to the robustness of the N=32 subshell closure are discussed, as well as the repercussions for a possible N=34 subshell closure

Core-coupled protons, f7/2 intruder states, and competing g 9/2 proton and neutron structures in 65,67Cu

The nuclei 65,67Cu were studied in reactions between a 430-MeV 64Ni beam and a thick 238U target with the Gammasphere array. Decay schemes for both nuclei have been extended, with spin and parity assignments of observed states constrained by measured γ-ray angular distributions and correlations. Positive-parity level structures, based on p3/2 protons coupled to negative-parity states in the Ni cores, have been identified above the known 9/2+ states. In 67Cu, a negative-parity dipole band built upon a πf7/2-1 state has been observed, as were two shorter negative-parity sequences. A qualitative description of the level structures has been obtained through comparison with systematics of the odd-A57-71Cu isotopes and with states in the neighboring even-even Ni and Zn cores. Shell-model calculations using JUN45 and jj44b effective interactions were performed for 65,67Cu, with jj44b providing overall better agreement with the data. Both are limited, however, by the restriction that the f7/2 and g9/2 orbitals are not available simultaneously in the basis. Proton f7/2 and neutron g9/2 orbitals are required for the full negative-parity spectrum of states, while g9/2 protons and neutrons are both important for positive-parity levels. The latter states are found to be better described in terms of weak coupling of a proton to the Ni core

Identification of the g9/2-proton bands in the neutron-rich Ga71,73,75,77 nuclei

Excited states in the odd-AGa71,73,75,77 nuclei have been populated in deep-inelastic reactions of a Ge76 beam at 530 MeV with a thick U238 target. High-spin sequences built upon the 9/2+, 5/2-, and 3/2- states were identified in all four isotopes. A comparison of the observed structures with the yrast positive-parity states in the neighboring even-even Zn cores indicates that the newly identified levels may be regarded as arising from the relatively weak coupling of the odd proton to the core states. However, significant contributions from broken pairs are expected to be present in this region of excitation energy. The present data set also provides clarification of previously reported decay paths of the low-energy levels in Ga71,73,75,77

The Physical Processes of CME/ICME Evolution

As observed in Thomson-scattered white light, coronal mass ejections (CMEs) are manifest as large-scale expulsions of plasma magnetically driven from the corona in the most energetic eruptions from the Sun. It remains a tantalizing mystery as to how these erupting magnetic fields evolve to form the complex structures we observe in the solar wind at Earth. Here, we strive to provide a fresh perspective on the post-eruption and interplanetary evolution of CMEs, focusing on the physical processes that define the many complex interactions of the ejected plasma with its surroundings as it departs the corona and propagates through the heliosphere. We summarize the ways CMEs and their interplanetary CMEs (ICMEs) are rotated, reconfigured, deformed, deflected, decelerated and disguised during their journey through the solar wind. This study then leads to consideration of how structures originating in coronal eruptions can be connected to their far removed interplanetary counterparts. Given that ICMEs are the drivers of most geomagnetic storms (and the sole driver of extreme storms), this work provides a guide to the processes that must be considered in making space weather forecasts from remote observations of the corona.Peer reviewe

Novel Δj=1 Sequence in Ge 78: Possible Evidence for Triaxiality

A sequence of low-energy levels in Ge327846 has been identified with spins and parity of 2+, 3+, 4+, 5+, and 6+. Decays within this band proceed strictly through ΔJ=1 transitions, unlike similar sequences in neighboring Ge and Se nuclei. Above the 2+ level, members of this sequence do not decay into the ground-state band. Moreover, the energy staggering of this sequence has the phase that would be expected for a γ-rigid structure. The energies and branching ratios of many of the levels are described well by shell-model calculations. However, the calculated reduced transition probabilities for the ΔJ=2 in-band transitions imply that they should have been observed, in contradiction with the experiment. Within the calculations of Davydov, Filippov, and Rostovsky for rigid-triaxial rotors with γ=30°, there are sequences of higher-spin levels connected by strong ΔJ=1 transitions which decay in the same manner as those observed experimentally, yet are calculated at too high an excitation energy

Seniority, collectivity, and B(E2) enhancement in 72Ni

Gamma rays assigned to 2872Ni44 have been identified with Gammasphere in deep-inelastic reactions involving a 450-MeV 76Ge beam and a 198Pt target. Using a combination of spectra produced by double gates on the known 454-, 843-, and 1095-keV members of the ground-state cascade, a coincident line at 199 keV has been identified and is tentatively assigned as the 8+→6 + transition. These γ-ray coincidences have been observed only in prompt events, indicating an 8+ half-life below 20 ns and requiring a large B(E2) enhancement compared to that expected from a seniority scheme. This value is consistent with models showing decay to a seniority ν=4, 6+ level that is depressed by the same two-body interaction responsible for the rather low 1095-keV 21+ energy, as compared to the valence-symmetry counterpart 4494Ru50