Taxonomic studies of the Rotifera (Phylum Aschelminthes) from a Central Amazonian varzea lake, Lago Camaleão (Ilha de Marchantaria, Rio Solimões, Amazonas, Brazil)

148 species of rotifers were identified in 22 plankton samples collected in Lago Camaleão, situated on the Ilha de Marchantaria, in the varzea region of the Solimões-Amazonas River system. During the low water period, February, 1981, 33 species were found. During the high water period, July, 1981, after the development of the aquatic vegetation, 138 species were identified. The decomposition of the inundated terrestrial vegetation favors those rotifer species which live on the surface of putrid mud. All are cosmopolitan species of the genera Lepadella, Mytilina, Platyias, Brachionus and Testudinella. Bdelloidea was represented by several species of the genus Rotaria. Several identification errors of former authors were revised, and in this study the following are proposed: Brachionus urceolaris amazonica n. ssp., Keratella nhamunda nov. nom., Lecane (s. str.) aimazoniana nov. nom., Lecane aspasia amazonica n. ssp. New records for the Amazon region include: Lecane (s. str.) stichaeoides HAUER 1938, Mytilina unguipes (LUCKS 1912), Testudinella greeni KOSTE 1981, and Testudinella patina dendradena (DE BEAUCHAMP 1955). Three new taxa are described: Cephatodelta paggia n. sp., Lecane (Monostyla) marchantaria n. sp., and Lepadella (L.) minoruoides n. sp

Investigation of electronic switches for analog and hybrid computation technical note no. 6

Analog switching circuits for analog and hybrid computer

The parasitic crustaceans of fishes from the Brazilian Amazon. 12. Ergasilus hydrolycus n.sp. (Copepoda: Poecilostomatoida) from Hydrolycus scomberoides (CUVIER)

The female of Ergasilus hydrolycus n. sp. is described from specimens taken from the gills of an Amazonian fish, Hydrolycus scomberoides (CUVIER). The new species is similar to E. bryconis THATCHER, 1981, and to E. jaraquensis THATCHER & ROBERTSON, 1982, in the form of the body, antennae and legs, and in having a curved pectinate seta on the terminal segment of the first exopod. The new species is distinguished from the other two by having a single seta representing the fifth leg, instead of two, and by having a relatively larger antennal claw. Additionally, the pigmentation of E. hydrolycus n. sp., is limited to a single transverse band at the level of the mouth while in the other two species it is diffuse and distributed throughout the body. Also, the uropod of the new species has two main setae and that of E. bryconis has three. The new species is larger than E. jaraquensis

About the relationship between the zooplankton and fluctuating water levels of Lago Camaleão, a Central Amazonian várzea lake

A two-year study of the composition and abundance of the zooplankton was conducted in an Amazonian vãrzea lake, Lago Camaleão. Rotifers were dominant in terms of both species numbers and density. The extremely low standing-stock observed during the high water period is attributed to prevailing poor oxygen conditions and, during extreme floods, current. The species associations of rotifers also reflect the flooding regime and its consequences

Increasing the compression pressure in an engine by using a long intake pipe

During some tests of a one-cylinder engine, using gas oil (diesel engine oil, specific gravity 0.86 at 60 F) with solid injection and compression ignition, it was found to be necessary to increase either the jacket water temperature or the compression pressure in order to start the engine. It was found that a sufficient increase in compression pressure could be obtained simply by attaching a long pipe to the inlet flange of the cylinder. However, since no data were available giving the values of the increase in compression pressure that might be expected from such a step-up, an investigation was made covering some engine speeds between 500 r.p.m. and 1800 r.p.m. The data obtained are included here in the form of curves. Although this data is not strictly applicable to another engine, it should give indications of what might be expected with such a set-up on an engine operating at similar speeds. The engine used was a single cylinder Liberty, 5-inch bore and 7-inch stroke, having standard cylinder, cams, valves, and valve timing and operating on a four-stroke cycle

Man's capability for self-locomotion on the moon. Phase 2 - Bungee simulator evaluation

Design and performance of suspension system for lunar gravity simulatio

Study of man pulling a cart on the moon

Metabolic cost evaluation of self-locomotion in simulated lunar gravity using space suits and carts including weight load and surface effect

Prior parameter uncertainty: Some implications for forecasting and policy analysis with VAR models

Models used for policy analysis should generate reliable unconditional forecasts as well as policy simulations (conditional forecasts) that are based on a structural model of the economy. Vector autoregression (VAR) models have been criticized for having inaccurate forecasts as well as being difficult to interpret in the context of an underlying economic model. In this paper, we examine how the treatment of prior uncertainty about parameter values can affect forecasting accuracy and the interpretation of identified structural VAR models. ; Typically, VAR models are specified with long lag orders and a diffuse prior about the unrestricted coefficients. We find evidence that alternatives that emphasize nonstationary aspects of the data as well as parsimony in parameterization have better out-of-sample forecast performance and smoother and more persistent responses to a given exogenous monetary policy change than do unrestricted VARs.Forecasting ; Vector autoregression ; Econometric models

Evaluation of the metabolic cost of locomotion in an Apollo space suit

Evaluation of metabolic cost of locomotion in Apollo space sui

Improving forecasts of the federal funds rate in a policy model

Vector autoregression (VAR) models are widely used for policy analysis. Some authors caution, however, that the forecast errors of the federal funds rate from such a VAR are large compared to those from the federal funds futures market. From these findings, it is argued that the inaccurate federal funds rate forecasts from VARs limit their usefulness as a tool for guiding policy decisions. In this paper, we demonstrate that the poor forecast performance is largely eliminated if a Bayesian estimation technique is used instead of OLS. In particular, using two different data sets we show that the forecasts from the Bayesian VAR dominate the forecasts from OLS VAR models—even after imposing various exact exclusion restrictions on lags and levels of the data.Forecasting ; Federal funds rate ; Vector autoregression