Site-specific Approaches to Cotton Insect Control. Sampling and Remote Sensing Analysis Techniques     

J.?L.?WillersEmail author  J.?N.?Jenkins  W.?L.?Ladner  P.?D.?Gerard  D.?L.?Boykin  K.?B.?Hood  P.?L.?McKibben  S.?A.?Samson  M.?M.?Bethel 《Precision Agriculture》2005,6(5):431-452

When insect population density varies within the same cotton field, estimation of abundance is difficult. Multiple population densities of the same species occur because cotton fields (due to edaphic and environmental effects) are apportioned into various habitats that are colonized at different rates. These various habitats differ temporally in their spatial distributions, exhibiting varying patterns of interspersion, shape and size. Therefore, when sampling multiple population densities without considering the influence of habitat structure, the estimated population mean represents a summary of diverse population distributions having different means and variances. This single estimate of mean abundance can lead to pest management decisions that are incorrect because it may over- or under-estimate pest density in different areas of the field. Delineation of habitat classes is essential in order to make local control decisions. Within large commercial cotton fields, it is too laborious for observers on the ground to map habitat boundaries, but remote sensing can efficiently create geo-referenced, stratified maps of cotton field habitats. By employing these maps, a simple random sampling design and larger sample unit sizes, it is possible to estimate pest abundance in each habitat without large numbers of samples. Estimates of pest abundance by habitat, when supplemented with ecological precepts and consultant/producer experience, provide the basis for spatial approaches to pest control. Using small sample sizes, the integrated sampling methodology maps the spatial abundance of a cotton insect pest across several large cotton fields.  相似文献   

ANTON JULIUS CARLSON     

Gerard RW  Ivy AC 《Science (New York, N.Y.)》1944,99(2560):51-52

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The rise of the rhizosolenid diatoms     

Damsté JS  Muyzer G  Abbas B  Rampen SW  Massé G  Allard WG  Belt ST  Robert JM  Rowland SJ  Moldowan JM  Barbanti SM  Fago FJ  Denisevich P  Dahl J  Trindade LA  Schouten S 《Science (New York, N.Y.)》2004,304(5670):584-587

The 18S ribosomal DNA molecular phylogeny and lipid composition of over 120 marine diatoms showed that the capability to biosynthesize highly branched isoprenoid (HBI) alkenes is restricted to two specific phylogenetic clusters, which independently evolved in centric and pennate diatoms. The molecular record of C25 HBI chemical fossils in a large suite of well-dated marine sediments and petroleum revealed that the older cluster, composed of rhizosolenid diatoms, evolved 91.5 +/- 1.5 million years ago (Upper Turonian), enabling an accurate dating of the pace of diatom evolution that is unprecedented. The rapid rise of the rhizosolenid diatoms probably resulted from a major reorganization of the nutrient budget in the mid-Cretaceous oceans, triggered by plate tectonics.  相似文献   

Use of Mohs Micrographically Controlled Surgery in the Management of Equine Penile Squamous Cell Carcinoma     

Paul G. Hazen  Brett Berthold  Karen L. Turgeon  Gerard Nuovo 《Journal of Equine Veterinary Science》2009

A 30-year-old palomino Standardbred horse was seen with a persistent penile squamous cell carcinoma. After failure using multiple treatments, surgical removal was successfully carried out under local anesthesia using Mohs micrographically controlled surgery. Subsequent examination of the malignant tissue identified bovine papillomavirus exclusively within the nuclei and cytoplasm of tumor cells. The use of Mohs surgery would appear to be useful as an effective, precisely controlled treatment for managing genital squamous cell carcinoma in equine subjects. The presence of papillomavirus within tumor cells would suggest the possibility of causation by an oncogenic papilloma virus and would indicate that careful monitoring of the surgical site should be performed.  相似文献   

Osseous cyst‐like lesions of the lateral intertubercular groove of the proximal humerus: A report of 5 cases     

D. Little  W. R. Redding  M. P. Gerard 《Equine Veterinary Education》2009,21(2):60-66

This report documents the case presentation, evaluation, treatment and outcome of 5 horses with an osseous cystlike lesion (OCLL) of the intertubercular groove of the proximal aspect of the humerus. In 3 of the 5 cases, delayed phase gamma scintigraphic findings demonstrated increased radiopharmaceutical uptake in the region of the intermediate tubercle of the proximal humerus of the affected limb, demonstrating increased bone remodelling in this region. In 4 of the 5 horses, an OCLL was identified in the intermediate tubercle of the proximal humerus, and in one horse the OCLL was identified in the greater tubercle. Medial‐lateral and craniomedial‐caudolateral oblique radiographic views were helpful to see the lesions in all cases. Ultrasonography confirmed the location of the subchondral and fibrocartilage defect associated with the OCLL and confirmed communication of the cyst with the lateral intertubercular groove of the humerus in 3 of the 5 cases. Ultrasonography also confirmed a variable degree of bicipital tendonitis in 3 of the horses. OCLL of the lateral intertubercular groove of the proximal humerus should be considered in the evaluation of any mature horse with lameness isolated to the bicipital bursa. Development of these OCLL may be a result of trauma or altered limb biomechanics as a result of shoulder osteoarthritis or concurrent chronic lameness, which leads to disruption or thinning of the fibrocartilage, remodelling of the subchondral bone and subsequent cyst development.  相似文献   

Reproductive ecology and scientific inference of steepness: a fundamental metric of population dynamics and strategic fisheries management     

Marc Mangel  Jon Brodziak  & Gerard DiNardo 《Fish and Fisheries》2010,11(1):89-104

The relationship between the biomass of reproductively mature individuals (spawning stock) and the resulting offspring added to the population (recruitment), the stock–recruitment relationship, is a fundamental and challenging problem in all of population biology. The steepness of this relationship is commonly defined as the fraction of recruitment from an unfished population obtained when the spawning stock biomass is 20% of its unfished level. Since its introduction about 20 years ago, steepness has become widely used in fishery management, where it is usually treated as a statistical quantity. Here, we investigate the reproductive ecology of steepness, using both unstructured and age-structured models. We show that if one has sufficient information to construct a density-independent population model (maximum per capita productivity and natural mortality for the unstructured case or maximum per capita productivity, natural mortality and schedules of size and maturity at age for the structured model) then one can construct a point estimate for steepness. Thus, steepness cannot be chosen arbitrarily. If one assumes that the survival of recruited individuals fluctuates within populations, it is possible, by considering the early life history, to construct a prior distribution for steepness from this same demographic information. We develop the ideas for both compensatory (Beverton–Holt) and over-compensatory (Ricker) stock–recruitment relationships. We illustrate our ideas with an example concerning bluefin tuna ( Thunnus thynnus/orientalis , Scombridae). We show that assuming that steepness is unity when recruitment is considered to be environmentally driven is not biologically consistent, is inconsistent with a precautionary approach, and leads to the wrong scientific inference (which also applies for assigning steepness any other single value).  相似文献   

Synthesis and Biological Activity of Allosamidin and Allosamidin Analogues     

Regine Blattner  Philippa J. Gerard  Margarethe Spindler-Barth 《Pest management science》1997,50(4):312-318

The chitinase inhibitor/insect ecdysis inhibitor allosamidin and eight allosamidin analogues have been synthesised from simple carbohydrate starting materials. Allosamidin was assayed against Tineola bisselliella (Hummel) larvae and all nine compounds were examined for their effects on the development of larvae of Lucilia cuprina (Wiedemann). High larval mortality compared to controls resulted when T. bisselliella and L. cuprina larva were exposed to allosami-din. The (1→3) linked regioisomer, the dimeric analogue and the gluco-configurated dimeric analogue of allosamidin all showed high activity against L. cuprina larvae. The regioisomer, the (1→3) linked isomer and its dimeric analogue, as well as the monomer allosamizoline and its regioisomer, were inactive. These new in-vivo results are consistent with known in-vitro insect chitinase inhibition data, in that greatest larval mortality was exhibited by the best inhibitors. © 1997 SCI  相似文献   

The need for clear and comparable terminology in benthic ecology. Part I. Ecological concepts     

Jean‐Claude Dauvin  Gerard Bellan  Denise Bellan‐Santini 《水产资源保护:海洋与淡水生态系统》2008,18(4):432-445

• 1. This note highlights problems with the definition and use of terminology in the field of benthic ecology, and compares the French classification with the UK and EUNIS classifications. These problems stem partly from language‐related difficulties, particularly the translation from English to French and vice versa, but also from the incoherence of certain typologies used in EU classifications and Directives.
• 2. The boundaries used by legislators and developers take neither ecological constraints nor environmental parameters into account. Most often, these boundaries are set using distances or depths that have no basis in the distribution of benthic species.
• 3. Retaining the definition of ‘étage’ that was proposed by Pérès (1961) is recommended, and the following classification hierarchy is proposed: supralittoral, mediolittoral, infralittoral with an upper littoral fringe, circalittoral with distinct coastal circalittoral and open circalittoral zones, bathyal, abyssal and hadal.

Copyright © 2007 John Wiley & Sons, Ltd.  相似文献