LANDSAT D local user terminal study

The effect of the changes incorporated in the LANDSAT D system on the ability of a local user terminal to receive, record and process data in real time was studied. Alternate solutions to the problems raised by these changes were evaluated. A loading analysis was performed in order to determine the quantities of data that a local user terminal (LUT) would be interested in receiving and processing. The number of bits in an MSS and a TM scene were calculated along with the number of scenes per day that an LUT might require for processing. These then combined to a total number of processed bits/day for an LUT as a function of sensor and coverage circle radius

Design of Marine Protected Areas on high seas and territorial waters of rockall bank

Fisheries closures are rapidly being developed to protect vulnerable marine ecosystems worldwide. Satellite monitoring of fishing vessel activity indicates that these closures can work effectively with good compliance by international fleets even in remote areas. Here we summarise how remote fisheries closures were designed to protect Lophelia pertusa habitat in a region of the NE Atlantic that straddles the EU fishing zone and the high seas. We show how scientific records, fishers' knowledge and surveillance data on fishing activity can be combined to provide a powerful tool for the design of Marine Protected Areas. © Inter-Research 2009

High energy cosmic-ray interactions with particles from the Sun

Cosmic-ray protons with energies above $10^{16}$ eV passing near the Sun may interact with photons emitted by the Sun and be excited to a $\Delta^+$ resonance. When the $\Delta^+$ decays, it produces pions which further decay to muons and photons which may be detected with terrestrial detectors. A flux of muons, photon pairs (from $\pi^0$ decay), or individual high-energy photons coming from near the Sun would be a rather striking signature, and the flux of these particles is a fairly direct measure of the flux of cosmic-ray nucleons, independent of the cosmic-ray composition. In a solid angle within $15^\circ$ around the Sun the flux of photon pairs is about \SI{1.3e-3}{} particles/(km$^2\cdot$yr), while the flux of muons is about \SI{0.33e-3}{} particles/(km$^2\cdot$yr). This is beyond the reach of current detectors like the Telescope Array, Auger, KASCADE-Grande or IceCube. However, the muon flux might be detectable by next-generation air shower arrays or neutrino detectors such as ARIANNA or ARA. We discuss the experimental prospects in some detail. Other cosmic-ray interactions occuring close to the Sun are also briefly discussed.Comment: 8 pages, 11 figure

The effect of quantization on the FCIQMC sign problem

The sign problem in Full Configuration Interaction Quantum Monte Carlo (FCIQMC) without annihilation can be understood as an instability of the psi-particle population to the ground state of the matrix obtained by making all off-diagonal elements of the Hamiltonian negative. Such a matrix, and hence the sign problem, is basis dependent. In this paper we discuss the properties of a physically important basis choice: first versus second quantization. For a given choice of single-particle orbitals, we identify the conditions under which the fermion sign problem in the second quantized basis of antisymmetric Slater determinants is identical to the sign problem in the first quantized basis of unsymmetrized Hartree products. We also show that, when the two differ, the fermion sign problem is always less severe in the second quantized basis. This supports the idea that FCIQMC, even in the absence of annihilation, improves the sign problem relative to first quantized methods. Finally, we point out some theoretically interesting classes of Hamiltonians where first and second quantized sign problems differ, and others where they do not.Comment: 4 pages w/ 2 page appendix, 2 figures, 1 tabl

Ocean acidification and the loss of phenolic substances in marine plants.

Rising atmospheric CO(2) often triggers the production of plant phenolics, including many that serve as herbivore deterrents, digestion reducers, antimicrobials, or ultraviolet sunscreens. Such responses are predicted by popular models of plant defense, especially resource availability models which link carbon availability to phenolic biosynthesis. CO(2) availability is also increasing in the oceans, where anthropogenic emissions cause ocean acidification, decreasing seawater pH and shifting the carbonate system towards further CO(2) enrichment. Such conditions tend to increase seagrass productivity but may also increase rates of grazing on these marine plants. Here we show that high CO(2) / low pH conditions of OA decrease, rather than increase, concentrations of phenolic protective substances in seagrasses and eurysaline marine plants. We observed a loss of simple and polymeric phenolics in the seagrass Cymodocea nodosa near a volcanic CO(2) vent on the Island of Vulcano, Italy, where pH values decreased from 8.1 to 7.3 and pCO(2) concentrations increased ten-fold. We observed similar responses in two estuarine species, Ruppia maritima and Potamogeton perfoliatus, in in situ Free-Ocean-Carbon-Enrichment experiments conducted in tributaries of the Chesapeake Bay, USA. These responses are strikingly different than those exhibited by terrestrial plants. The loss of phenolic substances may explain the higher-than-usual rates of grazing observed near undersea CO(2) vents and suggests that ocean acidification may alter coastal carbon fluxes by affecting rates of decomposition, grazing, and disease. Our observations temper recent predictions that seagrasses would necessarily be "winners" in a high CO(2) world

In the Shadows of Sunlight: The Effects of Transparency on State Political Campaigns

In recent years, the courts have invalidated a variety of campaign finance laws while simultaneously upholding disclosure requirements. Courts view disclosure as a less-restrictive means to root out corruption while critics claim that disclosure chills speech and deters political participation. Using individual-level contribution data from state elections between 2000 and 2008, we find that the speech-chilling effects of disclosure are negligible. On average, less than one donor per candidate is likely to stop contributing when the public visibility of campaign contributions increases. Moreover, we do not observe heterogeneous effects for small donors or ideological outliers despite an assumption in First Amendment jurisprudence that these donors are disproportionately affected by campaign finance regulations. In short, the argument that disclosure chills speech is not strongly supported by the data

Citizens United, States Divided: An Empirical Analysis of Independent Political Spending

What effect has Citizens United v. FEC had on independent spending in American politics? Previous attempts to answer this question have focused solely on federal elections, where there is no baseline for comparing changes in spending behavior. We overcome this limitation by examining the effects of Citizens United as a natural experiment on the states. Before Citizens United, about half of the states banned corporate independent expenditures and thus were “treated” by the Supreme Court’s decision, which invalidated these state laws. We rely on recently released state-level data to compare spending in “treated” states to spending in the “control” states, which have never banned corporate or union independent expenditures. We find that, while independent expenditures increased in both treated and control states between 2006 and 2010, the increase was more than twice as large in the treated states, and nearly all of the new money was funneled through nonprofit organizations and political committees where weak disclosure laws and practices protected the anonymity of the spenders. Finally, we observe that the increase in spending after Citizens United was not the product of fewer, larger expenditures as many scholars and pundits predicted, and we note that people were just as likely to make smaller expenditures (less than $400) after Citizens United as they were before. This finding is particularly striking because it cuts against the conventional wisdom of spending behavior and also challenges the logic of those who disagree with the most controversial element of the Citizens United decision—the rejection of political equality as a valid state interest