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

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

Evaluation of metabolic cost of locomotion in Apollo space sui

Observations on lunar gravity simulation

Physiological factors in astronaut performance in simulated lunar gravit

NOS/NGS activities to support development of radio interferometric surveying techniques

National Geodetic Survey activities towards the development of operational geodetic survey systems based on radio interferometry are reviewed. Information about the field procedures, data reduction and analysis, and the results obtained to date is presented

Arkansas Cotton Variety Test 2002

The primary aim of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed dealers establish marketing strategies and assists producers in choosing varieties to plant. In this way, the annual test facilitates the inclusion of new, improved genetic material into Arkansas cotton production. Variety adaptation is determined by evaluation of the varieties and lines at four University of Arkansas research stations located near Keiser, Clarkedale, Marianna, and Rohwer. Tests are duplicated in irrigated and non-irrigated culture at the Keiser and Marianna locations. In 2002, 37 entries were evaluated in the main test and 25 were evaluated in the first-year test. This report also includes the Mississippi County Cotton Variety Test (a large-plot, on-farm evaluation of 12 Round-up Ready varieties) and 12 other on-farm cotton variety tests conducted by the University of Arkansas Cooperative Extension Service

Prevalence, Incidence, and Spatial Dependence of Soybean mosaic virus in Iowa

The prevalence of soybean fields with plants infected with Soybean mosaic virus (SMV) in Iowa is assumed to be random, because the primary source of the virus is SMV-infected seed. Data collected from 2,500 soybean fields sampled over a 3-year period as part of the Iowa Soybean Disease Survey (2005 to 2007) were used to evaluate this assumption. SMV was first detected in early June of each year but counties in which it was first detected varied among years. Prevalence at the county scale at end of season was 32.3, 27.3, and 89.9% in 2005, 2006, and 2007, respectively. End-of-season incidence of SMV within SMV-positive counties was 1.5 to 25.0, 1.7 to 24, and 1.8 to 58% in 2005, 2006, and 2007, respectively. The number of fields in which plants infected with SMV were detected increased at the linear rate of approximately one new field every 2 days in 2007, compared with one new field every 22 days (2005) and 21 days (2006), with coefficients of determination (R2) of 93.2 to 96.8% using the linear model. Weak spatial dependence for end-of-season SMV incidence was detected using Moran\u27s Index, indicating that the risk for SMV incidence at the county scale within Iowa at the end of the growing season is not random

Hybrid functional calculations of the Al impurity in silica: Hole localization and electron paramagnetic resonance parameters

We performed first-principle calculations based on the supercell and cluster approaches to investigate the neutral Al impurity in smoky quartz. Electron paramagnetic resonance measurements suggest that the oxygens around the Al center undergo a polaronic distortion which localizes the hole being on one of the four oxygen atoms. We find that the screened exchange hybrid functional successfully describes this localization and improves on standard local density approaches or on hybrid functionals that do not include enough exact exchange such as B3LYP. We find a defect level at about 2.5 eV above the valence band maximum, corresponding to a localized hole in a O 2p orbital. The calculated values of the g tensor and the hyperfine splittings are in excellent agreement with experiment.Comment: 5 pages, 2 figures, 1 tabl

Further taxonomical studies of the Rotifera from Lago Camaleão, a Central Amazonian várzea lake (Ilha de Marchantaria, Rio Solimões, Amazonas, Brazil)

175 species of rotifers were identified in samples collected in lago Camaleão, an Amazonian varzea lake. 24 species which had previously been found in the lake (KOSTE & ROBERTSON 1983) did not reoccur, but were "replaced" by 30 others. Among these, new records for the Amazon region include: Atrochus tentaculatus WIERZEJSKI, 1893, Brachionus bidentatus inermis ANDERSON, 1899, Cephalodella catellina catellina (O. F. MÜLLER 1786), Eosphora anthadis HARRING & MYERS, 1922 and Monommata cf. actices MYERS, 1930. One new species is described, Cephalodella friebei, and the present taxonomic status of Filinia saltator (GOSSE 1886) and Macrochaetus serrcus (THORPE 1893) is discussed

Probabilistic models of information retrieval based on measuring the divergence from randomness

We introduce and create a framework for deriving probabilistic models of Information Retrieval. The models are nonparametric models of IR obtained in the language model approach. We derive term-weighting models by measuring the divergence of the actual term distribution from that obtained under a random process. Among the random processes we study the binomial distribution and Bose--Einstein statistics. We define two types of term frequency normalization for tuning term weights in the document--query matching process. The first normalization assumes that documents have the same length and measures the information gain with the observed term once it has been accepted as a good descriptor of the observed document. The second normalization is related to the document length and to other statistics. These two normalization methods are applied to the basic models in succession to obtain weighting formulae. Results show that our framework produces different nonparametric models forming baseline alternatives to the standard tf-idf model

Quantifying the Effect of Pyraclostrobin on Grainfill Period and Kernel Dry Matter Accumulation in Maize

Strobilurin fungicides are effective against a wide range of foliar fungal diseases on several crops and may offer additional physiological benefits, including plants staying green longer than normal (the stay-green effect ). It has been hypothesized that the stay-green effect may extend the grain fill period leading to increased grain yield due to a longer period of dry matter accumulation. We investigated the effect of pyraclostrobin fungicide applied at tasseling on foliar disease suppression, stalk rot severity, the stay-green effect of leaves in the upper canopy, dry matter accumulation, time at physiological maturity, grain yield, and moisture at harvest in maize from 2008 through 2010 in Iowa at six location years. Foliar disease severity was0.1) between pyraclostrobin-treated and non-treated maize in all location years, treated plots tended to have higher yield and grain moisture. Time at physiological maturity did not differ between pyraclostrobin-treated and nontreated plots (P \u3e 0.1). Although we demonstrated an application of pyraclostrobin to maize delayed senescence of the leaves thus contributing to the stay-green effect, our data did not show grain-fill period extension