871 research outputs found
TB81: Investigations on the Life History and Habits of Pityokteines sparsus (Coleoptera: Scolytidae)
The primary objectives of this study are (1) to investigate the life history of Pityokteines sparsus (LeConte) in the Oxbow area of northern Maine; (2) to study the seasonal and daily flight behavior of the insect; (3) to investigate the food energy relations of the species.https://digitalcommons.library.umaine.edu/aes_techbulletin/1110/thumbnail.jp
TB80: Scanning Electron Microscopy of Insects: Techniques for the Novice
The scanning electron microscope (SEM) has been used to detail the morphology of small insects; however, it is often difficult for the novice to obtain acceptable results without time-consuming and costly experimentation. This brief paper outlines some of the techniques and problems encountered in an examination of the balsam bark beetle Pityokteines sparsus (Le Conte ) and the hymenopterous parasitoid Brachymeria intermedia (Nees). The information presented herein is mainly for the benefit of individuals wishing to use the SEM but having little or no experience concerning the special problems associated with the photography of insect specimens, and may form a base from which reasonable results can be obtained after limited experimentation.https://digitalcommons.library.umaine.edu/aes_techbulletin/1109/thumbnail.jp
Developing Intensity-Duration-Frequency (IDF) Curves From Satellite-Based Precipitation: Methodology and Evaluation
Given the continuous advancement in the retrieval of precipitation from satellites, it is important to develop methods that incorporate satellite-based precipitation data sets in the design and planning of infrastructure. This is because in many regions around the world, in situ rainfall observations are sparse and have insufficient record length. A handful of studies examined the use of satellite-based precipitation to develop intensity-duration-frequency (IDF) curves; however, they have mostly focused on small spatial domains and relied on combining satellite-based with ground-based precipitation data sets. In this study, we explore this issue by providing a methodological framework with the potential to be applied in ungauged regions. This framework is based on accounting for the characteristics of satellite-based precipitation products, namely, adjustment of bias and transformation of areal to point rainfall. The latter method is based on previous studies on the reverse transformation (point to areal) commonly used to obtain catchment-scale IDF curves. The paper proceeds by applying this framework to develop IDF curves over the contiguous United States (CONUS); the data set used is Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks â Climate Data Record (PERSIANN-CDR). IDFs are then evaluated against National Oceanic and Atmospheric Administration (NOAA) Atlas 14 to provide a quantitative estimate of their accuracy. Results show that median errors are in the range of (17â22%), (6â12%), and (3â8%) for one-day, two-day and three-day IDFs, respectively, and return periods in the range (2â100) years. Furthermore, a considerable percentage of satellite-based IDFs lie within the confidence interval of NOAA Atlas 14
Improving efficiency of pig feed manufacturing and application of additives
The project has demonstrated that processed feeds with similar ingredient mixtures differ widely between mills in throughput, energy use, pellet hardness and durability and nutritional quality for growing pigs. Preparation of grains before mixing, specific ingredients and additives used as well as the physical structure of the processing units all affect the cost of manufacture and physical and nutritional quality of the finished product
Ogre and Pythia: An Invariance Proof Method for Weak Consistency Models
We design an invariance proof method for concurrent programs parameterised by a weak consistency model. The calculational design of the invariance proof method is by abstract interpretation of a truly parallel analytic semantics. This generalises the methods by Lamport and Owicki-Gries for sequential consistency. We use cat as an example of language to write consistency specifications of both concurrent programs and machine architectures
The âSpirit of New Orleansâ : translating a model of intervention with maltreated children and their families for the Glasgow context
Peer reviewedPreprin
Trends in Antarctic Peninsula surface melting conditions from observations and regional climate modeling
Multidecadal meteorological station records and microwave backscatter time-series from the SeaWinds scatterometer onboard QuikSCAT (QSCAT) were used to calculate temporal and spatial trends in surface melting conditions on the Antarctic Peninsula (AP). Four of six long-term station records showed strongly positive and statistically significant trends in duration of melting conditions, including a 95% increase in the average annual positive degree day sum (PDD) at Faraday/Vernadsky, since 1948. A validated, threshold-based melt detection method was employed to derive detailed melt season onset, extent, and duration climatologies on the AP from enhanced resolution QSCAT data during 1999â2009. Austral summer melt on the AP was linked to regional- and synoptic-scale atmospheric variability by respectively correlating melt season onset and extent with November near-surface air temperatures and the OctoberâJanuary averaged index of the Southern Hemisphere Annular Mode (SAM). The spatial pattern, magnitude, and interannual variability of AP melt from observations was closely reproduced by simulations of the regional model RACMO2. Local discrepancies between observations and model simulations were likely a result of the QSCAT response to, and RACMO2 treatment of, ponded surface water, and the relatively crude representation of coastal climate in the 27âkm RACMO2 grid
Protostellar collapse: A comparison between SPH and AMR calculations
The development of parallel supercomputers allows today the detailed study of
the collapse and the fragmentation of prestellar cores with increasingly
accurate numerical simulations. Thanks to the advances in sub-millimeter
observations, a wide range of observed initial conditions enable us to study
the different modes of low-mass star formation. The challenge for the
simulations is to reproduce the observational results. Two main numerical
methods, namely AMR and SPH, are widely used to simulate the collapse and the
fragmentation of prestellar cores. We compare thoroughly these two methods
within their standard framework. We use the AMR code RAMSES and the SPH code
DRAGON. Our physical model is as simple as possible and consists of an
isothermal sphere rotating around the z-axis. We first study the conservation
of angular momentum as a function of the resolution. Then, we explore a wide
range of simulation parameters to study the fragmentation of prestellar cores.
There seems to be a convergence between the two methods, provided resolution in
each case is sufficient. Resolution criteria adapted to our physical cases, in
terms of resolution per Jeans mass, for an accurate description of the
formation of protostellar cores are deduced from the present study. This
convergence is encouraging for future work in simulations of low-mass star
formation, providing the aforementioned criteria are fulfilled.
Higher resolution figures can be downloaded at
http://www-dapnia.cea.fr/Projets/COAST/paper_amrvssph.pdfComment: 16 pages, 16 figures, accepted for publication in A&
Unemployment, Education and Skills Constraints in Post-Apartheid South Africa
This paper investigates the relationship between education and unemployment in post-apartheid South Africa, and probes the argument that employment growth has been inhibited particularly by skills constraints. We use probit regression analysis to show that higher education protected against unemployment in both 1995 and 2003, and that overall, the relative benefits to tertiary education rose over the period
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