115 research outputs found
Accuracy and Precision of Insect Density and Impact Estimates
In estimating insect density and impact, entomologists are understandably interested in accuracy of estimation, but they almost always are dealing with precision because of bias due to an invalid estimator, probability sampling, or nonsampling errors. Definitions related to statistical estimation are reviewed and the concepts of accuracy and precision examined.
Interval estimation and optimum sample size determination related to accuracy and precision, using the concept of allowable error, are examined. Criteria for selecting the best estimator in tenns of accuracy and precision are presented, and the distortion of probability statements due to bias is discussed. Accuracy and precision are compared and contrasted using two examples: (I) estimating insect density and (2) estimating insect impact. Adjusted and more accurate estimators can be obtained if the bias of an estimator can be estimated from a preliminary sample
Development of Empirical Models to Rate Spruce-Fir Stands in Michigan\u27s Upper Peninsula for Hazard From the Spruce Budworm (Lepidoptera: Tortricidae): A Case History
The procedure used to develop empirical models which estimate potential spruce budworm impact to spruce-fir stands in Michigan\u27s Upper Peninsula is reviewed. Criteria used to select independent variables, to select the best of alternative multiple linear regression models. and to validate final models are discussed. Preliminary, intermediate, and final results demonstrate a cyclic pattern to the development procedure. Validation is emphasized as an important step in the procedure. Implications of using the hazard-rating system as a pest management tool in the stand management process are discussed
Technology Transfer in Forest Pest Management: A Case History
The current approach being used in the spruce budworm technology transfer program for the Lake States is described. During 1981-1982, we concentrated on needs assessment surveys and the development and packaging of materials in five areas: general manual, chemical control handbook, silviculture handbook, instruction manual for remote sensing workshops, and technical reports on budworm impact on spruce-fir stands. We present a list of factors that researchers and technology transfer specialists should consider when plan- ning a research and technology transfer program in forest pest management
The Economics of Spruce Budworm Outbreaks in the Lake States: An Overview
Economic effects of spruce budworm outbreaks in the Lake States were examined. The recent outbreak caused spruce and fir mortality on 420 thousand ha (I.OS million acres) of commercial forest land in the Lake States. Two models of Lake States spruce-fir markets were developed. A Static Economic Model established the nature of the Lake States spruce-fir market and a Comparative Static Model examined changes brought about by spruce budworm outbreaks.
Outbreaks result in short-run supply shifts which probably decrease total revenue to stumpage owners but do not affect demand. The magnitude of long-run impacts were dependent on developing Lake States markets and forest management techniques. Further research is necessary on the value of short-run losses to stumpage owners so that the costs of forest management can be compared with outbreak losses. Long-run shifts in demand can be facilitated by attracting new industry to the area, developing new markets for the spruce-fir resource, and demonstrating that the spruce-fir resource can provide a continuous fiber source in the future.
These shifts would provide the price incentives that land managers require to undertake intensive forest management. Research on the development of new markets for the spruce-fir resource is needed. As markets develop, the long-run impacts become less severe. Technology transfer programs already exist to aid land managers in developing management strategies to increase yields of spruce-fir and minimize outbreak impact
Development of Empirical Models to Rate Spruce-Fir Stands in Michigan\u27s Upper Peninsula for Hazard From the Spruce Budworm (Lepidoptera: Tortricidae): A Case History
The procedure used to develop empirical models which estimate potential spruce budworm impact to spruce-fir stands in Michigan\u27s Upper Peninsula is reviewed. Criteria used to select independent variables, to select the best of alternative multiple linear regression models. and to validate final models are discussed. Preliminary, intermediate, and final results demonstrate a cyclic pattern to the development procedure. Validation is emphasized as an important step in the procedure. Implications of using the hazard-rating system as a pest management tool in the stand management process are discussed
Relationships between spruce budworm damage and site factors in spruce-fir-dominated ecosystems of Western Upper Michigan
Damage by the spruce budworm, Choristoneura fumiferana (Clemens), on balsam fir, Abies balsamea (L.) Mill., in local ecosystems (site units) of the Ottawa National Forest (western Upper Peninsula of Michigan, U.S.A.) was studied in relation to site factors. A multi-factor ecological approach was used to distinguish 25 spruce-fir-dominated ecosystems on a variety of different sites, ranging from dry-mesic outwash plains to river floodplains and swamps. Spruce budworm damage on balsam fir appears to be more directly related to site factors (specifically soil type and drainage class) than to stand parameters such as relative dominance or living-plus-dead basal area. Damage on balsam fir was greatest on wetland ecosystems with organic soils and on dryland ecosystems with impeded drainage. The heavy damage on these soils is probably a consequence of shallow rooting habit which predisposes the physiologically mature balsam fir to drought injury, lessened vigor, and a lessened ability to withstand defoliation. Black spruce, Picea mariana (Mill.) B.S.P., also exhibited heavy damage on sites where it is not well adapted, i.e. somewhat excessively drained dryland ecosystems. An understanding of the site factors and the ecosystem classification provide the basis for predicting where the greatest damage can be expected.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26584/1/0000125.pd
Integration of phylogenomics and molecular modeling reveals lineage-specific diversification of toxins in scorpions
Scorpions have evolved a variety of toxins with a plethora of biological targets, but characterizing their evolution has been limited by the lack of a comprehensive phylogenetic hypothesis of scorpion relationships grounded in modern, genome-scale datasets. Disagreements over scorpion higher-level systematics have also incurred challenges to previous interpretations of venom families as ancestral or derived. To redress these gaps, we assessed the phylogenomic relationships of scorpions using the most comprehensive taxonomic sampling to date. We surveyed genomic resources for the incidence of calcins (a type of calcium channel toxin), which were previously known only from 16 scorpion species. Here, we show that calcins are diverse, but phylogenetically restricted only to parvorder Iurida, one of the two basal branches of scorpions. The other branch of scorpions, Buthida, bear the related LKTx toxins (absent in Iurida), but lack calcins entirely. Analysis of sequences and molecular models demonstrates remarkable phylogenetic inertia within both calcins and LKTx genes. These results provide the first synapomorphies (shared derived traits) for the recently redefined clades Buthida and Iurida, constituting the only known case of such traits defined from the morphology of molecules
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Simulated tsunami inundation for a range of Cascadia megathrust earthquake scenarios at Bandon, Oregon, USA
Characterizations of tsunami hazards
along the Cascadia subduction zone hinge
on uncertainties in megathrust rupture
models used for simulating tsunami inundation.
To explore these uncertainties, we
constructed 15 megathrust earthquake scenarios
using rupture models that supply the
initial conditions for tsunami simulations
at Bandon, Oregon. Tsunami inundation
varies with the amount and distribution
of fault slip assigned to rupture models,
including models where slip is partitioned to
a splay fault in the accretionary wedge and
models that vary the updip limit of slip on a
buried fault. Constraints on fault slip come
from onshore and offshore paleoseismological
evidence. We rank each rupture model
using a logic tree that evaluates a model’s
consistency with geological and geophysical
data. The scenarios provide inputs to a
hydrodynamic model, SELFE, used to
simulate tsunami generation, propagation,
and inundation on unstructured grids with
<5–15 m resolution in coastal areas. Tsunami
simulations delineate the likelihood
that Cascadia tsunamis will exceed mapped
inundation lines. Maximum wave elevations
at the shoreline varied from ~4 m to
25 m for earthquakes with 9–44 m slip and
M[subscript w] 8.7–9.2. Simulated tsunami inundation
agrees with sparse deposits left by the A.D.
1700 and older tsunamis. Tsunami simulations
for large (22–30 m slip) and medium
(14–19 m slip) splay fault scenarios encompass
80%–95% of all inundation scenarios
and provide reasonable guidelines for land-use
planning and coastal development. The
maximum tsunami inundation simulated for the greatest splay fault scenario (36–44 m slip) can help to guide development of
local tsunami evacuation zones
Support for UNRWA's survival
The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) provides life-saving humanitarian aid for 5·4 million Palestine refugees now entering their eighth decade of statelessness and conflict. About a third of Palestine refugees still live in 58 recognised camps. UNRWA operates 702 schools and 144 health centres, some of which are affected by the ongoing humanitarian disasters in Syria and the Gaza Strip. It has dramatically reduced the prevalence of infectious diseases, mortality, and illiteracy. Its social services include rebuilding infrastructure and homes that have been destroyed by conflict and providing cash assistance and micro-finance loans for Palestinians whose rights are curtailed and who are denied the right of return to their homeland
An innovative pay-for-performance (P4P) strategy for improving malaria management in rural Kenya: protocol for a cluster randomized controlled trial
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