A Taylor Rule for Fiscal Policy

In times of rapid macroeconomic change it would seem useful for both fiscal and monetary policy to be modified frequently. This is true for monetary policy with monthly meetings of the Open Market Committee. It is not true for fiscal policy which mostly varies with the annual Congressional budget cycle. This paper proposes a feedback framework for analyzing the question of whether or not movement from annual to quarterly fiscal policy changes would improve the performance of stabilization policy. More broadly the paper considers a complementary rather than competitive framework in which monetary policy in the form of the Taylor rule is joined by a similar fiscal policy rule. This framework is then used to consider methodological improvements in the Taylor and the fiscal policy rule to include lags, uncertainty in parameters and measurement errors.design of fiscal policy, optimal experimentation, stochastic optimization, time-varying parameters, numerical experiments

A Combined Compton and Coded-aperture Telescope for Medium-energy Gamma-ray Astrophysics

A future mission in medium-energy gamma-ray astrophysics would allow for many scientific advancements, e.g. a possible explanation for the excess positron emission from the Galactic Center, a better understanding of nucleosynthesis and explosion mechanisms in Type Ia supernovae, and a look at the physical forces at play in compact objects such as black holes and neutron stars. Additionally, further observation in this energy regime would significantly extend the search parameter space for low-mass dark matter. In order to achieve these objectives, an instrument with good energy resolution, good angular resolution, and high sensitivity is required. In this paper we present the design and simulation of a Compton telescope consisting of cubic-centimeter Cadmium Zinc Telluride (CdZnTe) detectors as absorbers behind a silicon tracker with the addition of a passive coded mask. The goal of the design was to create a very sensitive instrument that is capable of high angular resolution. The simulated telescope showed achievable energy resolutions of 1.68$\%$ FWHM at 511 keV and 1.11$\%$ at 1809 keV, on-axis angular resolutions in Compton mode of 2.63$^{\circ}$ FWHM at 511 keV and 1.30$^{\circ}$ FWHM at 1809 keV, and is capable of resolving sources to at least 0.2$^{\circ}$ at lower energies with the use of the coded mask. An initial assessment of the instrument in Compton imaging mode yields an effective area of 183 cm$^{2}$ at 511 keV and an anticipated all-sky sensitivity of 3.6 x 10$^{-6}$ photons cm$^{-2}$ s$^{-1}$ for a broadened 511 keV source over a 2-year observation time. Additionally, combining a coded mask with a Compton imager to improve point source localization for positron detection has been demonstrated

Obraz i zróżnicowanie języka mongolskiego na tle polszczyzny i polskości

Udostępnienie publikacji Wydawnictwa Uniwersytetu Łódzkiego finansowane w ramach projektu „Doskonałość naukowa kluczem do doskonałości kształcenia”. Projekt realizowany jest ze środków Europejskiego Funduszu Społecznego w ramach Programu Operacyjnego Wiedza Edukacja Rozwój; nr umowy: POWER.03.05.00-00-Z092/17-00

The relationship between substrate composition, community structure and feeding preferences of parrot fishes (Scaridae) in Anmardub, Guna Yala coastal reefs

Coral reefs are important marine ecosystems, as they support biodiversity and generate buffer zones, yet their abundance is incredibly limited globally. One of the main threats that coral reefs face is excessive macroalgal coverage, which limits sunlight from reaching corals, and thus, limits the energy that can reach them. Parrot fish (Scaridae) are keystone herbivores, as they consume macroalgae growing on corals, which aids in reef survivability. While there is previous research on the abundances, sizes, and feeding habits of Scaridae species in the Caribbean, there is no published research on how community structure and feeding preferences of parrot fishes differ within coral reef ecosystems of varying substrate composition. This study assesses the community structure and feeding preferences of Scaridae in the fringing and barrier reefs, reefs of differing substrate composition, of Anmardub Island in Guna Yala, Panama. To determine the substrate composition of fringing and barrier reefs, percent coverages of sand, algae, sponge, dead coral, fire coral, coral rubble, hard coral, and soft coral, were quantified using a 1m2 threaded quadrat along 6 30x1m belt transects at varying depth levels (0-2.0m, 2.1-4.0m, 4.1-6.0m) in each reef. These transects were placed 30m away from each other, and parallel to the shore. Using these same transects, visual censuses were conducted, in which Scaridae species within 1m of either side of the transects had their densities, size proportions (0-10.0cm, 10.1-20.0cm, 20.1cm+), and proportions of coral species consumption, recorded. Across all depth levels, the fringing reef has significantly higher percentages of sand coverage, t(62)=4.33, p\u3c.001; t(60)=7.78, p\u3c.001; t(59)=4.27, p\u3c.001, and dead coral coverage, t(59)=6.47, p\u3c.001; t(59)=8.72, p\u3c.001; t(59)=4.30, p\u3c.001, while the barrier reef has significantly higher percentages of hard coral coverage, t(116)=3.13, p=.0022; t(118)=8.03, p\u3c.001, at the 0-2.0m and 2.1-4.0m depth levels. Thus, the barrier reef is generally healthier and more consistent than the fringing reef. Scaridae species densities differ significantly between fringing and barrier reefs at the 0-2.0m depth level, X2 (4, N=184,164)=52.70, p\u3c.001, as there are significantly higher densities of Scarus iseri and Sparisoma rubripinne in the fringing reef, and significantly higher densities of Nicholsina usta, Sparisoma aurofrenatum, and Sparisoma viride in the barrier reef. Across all depths of fringing and barrier reefs, there is a weak positive correlation between substrate variability and Scaridae species diversity, R2=.0057, F(5)=.023, p=.89. There is also a significant difference in Scaridae coral species consumption proportions across all depth levels, X2 (3, N=140,54)=66.55, p\u3c.001; X2 (4, N=20,47)=53.07 p\u3c.001; X2 (6, N=76,94)=108.74, p\u3c.001, as significantly higher proportions of Scaridae consume macroalgae and algal turf on dead coral in the fringing reef, while significantly higher proportions of Scaridae consume macroalgae on coral rubble and Porites porites in the barrier reef. Based on these results, we can conclude that there is a relationship between coral reef substrate composition and Scaridae species densities at the 0-2.0m depth level, and across all depth levels, a relationship between coral reef substrate composition and Scaridae diversity and feeding preferences

Expected optimal feedback with Time-Varying Parameters

In this paper we derive the closed loop form of the Expected Optimal Feedback rule, sometimes called passive learning stochastic control, with time varying parameters. As such this paper extends the work of Kendrick (1981,2002, Chapter 6) where parameters are assumed to vary randomly around a known constant mean. Furthermore, we show that the cautionary myopic rule in Beck and Wieland (2002) model, a test bed for comparing various stochastic optimizations approaches, can be cast into this framework and can be treated as a special case of this solution.Optimal experimentation, stochastic optimization, time-varying parameters, expected optimal feedback