2,426 research outputs found
Degree-Day Summation and Hatching of the Forest Tent Caterpillar, \u3ci\u3eMalacosoma Disstria\u3c/i\u3e (Lepidoptera: Lasiocampidae)
(excerpt)
The forest tent caterpillar, Malacosoma disstria (Htibner), is a common defoliater of deciduous trees throughout most of the United States and Canada. It is a well known outbreak species, whose populations erupt periodically (every 10 to 16 years) when forest conditions are suitable. Typical outbreaks last three to six years in a given geographic area and then collapse as quickly as they arise. This note documents the relation between forest tent caterpillar egg hatching in the field and heat accumulation (degree-days) leading up to hatch. This information will permit (a) predicting the date on which eggs will hatch by summing degree days during the insect\u27s overwintering period, and (b) comparing with populations in other years and areas. The data came from an outbreak in northern Minnesota that began near International Falls in 1966 and collapsed in 1972 (Witter et al., 1975)
Biological inventory of the Southern Nevada Water Project, second stage
The present report is a biological inventory of the Southern Nevada Water Project, Second Stage. The boundaries of the project encompass sections of North Las Vegas, Las Vegas, East Las Vegas and areas along Las Vegas Wash extending to its drainage point in Las Vegas Bay in Lake Mead. Therefore, it encompasses a wide array of ecological situations and landscapes ranging from essentially natural to various stages of urban development.
This biological inventory presents basic ecological classifications, descriptions of vegetation, lists of vascular plants and vertebrates known to occur in the area. Each major group, i.e., plants, fish, amphibians, reptiles, birds and mammals are characterized ecologically by biotic community. Basic life history data are given for all species of vertebrates found on the project area. Species of special status such as threatened, endangered, protected or of game status are further discussed
Self-organization of hydrophobic soil and granular surfaces
Soil can become extremely water repellent following forest fires or oil spillages, thus preventing penetration of water and increasing runoff and soil erosion. Here the authors show that evaporation of a droplet from the surface of a hydrophobic granular material can be an active process, lifting, self-coating, and selectively concentrating small solid grains. Droplet evaporation leads to the formation of temporary liquid marbles and, as droplet volume reduces, particles of different wettabilities compete for water-air interfacial surface area. This can result in a sorting effect with self-organization of a mixed hydrophobic-hydrophilic aggregate into a hydrophobic shell surrounding a hydrophilic core
Isolation of viruses responsible for the demise of an Emiliania huxleyi bloom in the English Channel
This study used analytical flow cytometry (AFC) to monitor the abundance of phytoplankton, coccoliths, bacteria and viruses in a transect that crossed a high reflectance area in the western English Channel. The high reflectance area, observed by satellite, was caused by the demise of an Emiliania huxleyi bloom. Water samples were collected from depth profiles at four stations, one station outside and three stations inside the high reflectance area. Plots of transect data revealed very obvious differences between Station 1, outside, and Stations 2–4, inside the high reflectance area. Inside, concentrations of viruses were higher; E. huxleyi cells were lower; coccoliths were higher; bacteria were higher and virus:bacteria ratio was lower than at Station 1, outside the high reflectance area. This data can simply be interpreted as virus-induced lysis of E. huxleyi cells in the bloom causing large concentrations of coccoliths to detach, resulting in the high reflectance observed by satellite imagery. This interpretation was supported by the isolation of two viruses, EhV84 and EhV86, from the high reflectance area that lysed cultures of E. huxleyi host strain CCMP1516. Basic characterization revealed that they were lytic viruses approximately 170 nm–190 nm in diameter with an icosahedral symmetry. Taken together, transect and isolation data suggest that viruses were the major contributor to the demise of the E. huxleyi population in the high reflectance area. Close coupling between microalgae, bacteria and viruses contributed to a large organic carbon input. Consequent cycling influenced the succession of an E. huxleyi-dominated population to a more characteristic mixed summer phytoplankton community
IonFlow: a galaxy tool for the analysis of ionomics data sets.
INTRODUCTION: Inductively coupled plasma mass spectrometry (ICP-MS) experiments generate complex multi-dimensional data sets that require specialist data analysis tools. OBJECTIVE: Here we describe tools to facilitate analysis of the ionome composed of high-throughput elemental profiling data. METHODS: IonFlow is a Galaxy tool written in R for ionomics data analysis and is freely accessible at https://github.com/wanchanglin/ionflow . It is designed as a pipeline that can process raw data to enable exploration and interpretation using multivariate statistical techniques and network-based algorithms, including principal components analysis, hierarchical clustering, relevance network extraction and analysis, and gene set enrichment analysis. RESULTS AND CONCLUSION: The pipeline is described and tested on two benchmark data sets of the haploid S. Cerevisiae ionome and of the human HeLa cell ionome
Plastron properties of a superhydrophobic surface
Most insects and spiders drown when submerged during flooding or tidal inundation, but some are able to survive and others can remain submerged indefinitely without harm. Many achieve this by natural adaptations to their surface morphology to trap films of air, creating plastrons which fix the water-vapor interface and provide an incompressible oxygen-carbon dioxide exchange surface. Here the authors demonstrate how the surface of an extremely water-repellent foam mimics this mechanism of underwater respiration and allows direct extraction of oxygen from aerated water. The biomimetic principle demonstrated can be applied to a wide variety of man-made superhydrophobic materials
A 1.1 to 1.9 GHz SETI Survey of the Kepler Field: I. A Search for Narrow-band Emission from Select Targets
We present a targeted search for narrow-band (< 5 Hz) drifting sinusoidal
radio emission from 86 stars in the Kepler field hosting confirmed or candidate
exoplanets. Radio emission less than 5 Hz in spectral extent is currently known
to only arise from artificial sources. The stars searched were chosen based on
the properties of their putative exoplanets, including stars hosting candidates
with 380 K > T_eq > 230 K, stars with 5 or more detected candidates or stars
with a super-Earth (R_p 50 day orbit. Baseband voltage data
across the entire band between 1.1 and 1.9 GHz were recorded at the Robert C.
Byrd Green Bank Telescope between Feb--Apr 2011 and subsequently searched
offline. No signals of extraterrestrial origin were found. We estimate that
fewer than ~1% of transiting exoplanet systems host technological civilizations
that are radio loud in narrow-band emission between 1-2 GHz at an equivalent
isotropically radiated power (EIRP) of ~1.5 x 10^21 erg s^-1, approximately
eight times the peak EIRP of the Arecibo Planetary Radar, and we limit the the
number of 1-2 GHz narrow-band-radio-loud Kardashev type II civilizations in the
Milky Way to be < 10^-6 M_solar^-1. Here we describe our observations, data
reduction procedures and results.Comment: Accepted to the Astrophysical Journa
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