Movement patterns of three arboreal primates in a Neotropical moist forest explained by LiDAR-estimated canopy structure     

Kevin A. McLean  Anne M. Trainor  Gregory P. Asner  Margaret C. Crofoot  Mariah E. Hopkins  Christina J. Campbell  Roberta E. Martin  David E. Knapp  Patrick A. Jansen 《Landscape Ecology》2016,31(8):1849-1862

  相似文献   

Identification of survivin,an inhibitor of apoptosis,in canine urinary bladder transitional cell carcinoma*     

W. Velando Rankin  C. J. Henry  S. E. Turnquist  J. R. Turk  M. E. Beissenherz  J. W. Tyler  E. B. Rucker  D. W. Knapp  C. O. Rodriguez  J. A. Green 《Veterinary and comparative oncology》2008,6(3):141-150

  相似文献   

Relationship between changes in endogenous polyamines and seed quality during development of sh₂ sweet corn (Zea mays L.) seed     

D.D. Cao  J. Hu  S.J. Zhu  W.M. Hu  A. Knapp 《Scientia Horticulturae》2010

Polyamines putatively affect tolerance to abiotic stresses and are believed to be important in organogenesis. Present experiments investigate the relationship between polyamines (PAs) and seed quality. Therefore, during seed development, the changes in free putrescine (Put), spermidine (Spd) and spermine (Spm) and physiological and biochemical parameters in F₁ seeds of sh₂ sweet corn were compared. Concentrations of Put, Spd and Spm increased from 14 to 30 days after pollination (DAP). After 30 DAP Put concentration declined with an opposite trend to that of Spd and Spm. The regression analysis between PAs and seed quality described by physiological and biochemical parameters including germination percentage, germination energy, germination index, seed size, seed fresh and dry weight, total soluble sugar, total soluble protein, Malondialdehyde (MDA) concentration, electrolyte leakage, peroxidase (POD) and catalase (CAT) activity were conducted. Spd was observed to have a closer relation with the comprehensive physiological changes of seeds during their development than that of Put and Spm. Moreover, the Spm concentration might be more suitable to forecast seed germinability during seed maturation period than Spd and Put. It indicated that endogenous Spd and Spm in dissociated form had more effect than Put during seed development progress of sweet corn.  相似文献   

Extraction of rutin from buckwheat (Fagopyrum esculentumMoench) seeds and determination by capillary electrophoresis.     

S Kreft  M Knapp  I Kreft 《Journal of agricultural and food chemistry》1999,47(11):4649-4652

The content of the flavonoid rutin was determined in different milling fractions of buckwheat seeds and in buckwheat stems, leaves, and flowers. The extraction was performed by using a solvent containing 60% of ethanol and 5% of ammonia in water. The extracts were analyzed by capillary electrophoresis (running buffer of 50 mM borate (pH 9.3), 100 mM sodium dodecyl sulfate; determination at 380 nm). In bran fractions the concentration of rutin was 131-476 ppm, and in flour fractions 19-168 ppm. On average, about 300, 1000, and 46000 ppm of rutin were found in leaves, stems, and flowers, respectively. The results indicate that buckwheat could be an important nutritional source of flavonoids, especially in countries with a low mean daily flavonoid intake.  相似文献   

The nutrient footprint of a submerged‐cage offshore aquaculture facility located in the tropical Caribbean     

Aaron W. Welch  Angela N. Knapp  Sharein El Tourky  Zachary Daughtery  Gary Hitchcock  Daniel Benetti 《Journal of the World Aquaculture Society》2019,50(2):299-316

The effect of effluent generated by a commercially scaled offshore (~13 km) finfish aquaculture facility in the tropical Caribbean on the water column and benthic nutrients and chlorophyll‐a is described. Water column samples were collected up‐ and downstream of the site at various times between 2012 and 2018. Typically, no significant difference in dissolved oxygen, chlorophyll‐a, particulate organic carbon, particulate organic nitrogen, nitrate + nitrite, and total dissolved nitrogen concentration was observed in the water column between the up‐ versus downstream samples. Similarly, sediment samples were collected at various times between 2012 and 2018. Samples were collected at up‐ versus downstream locations and analyzed for benthic carbon, nitrogen, and chlorophyll‐a content. Some of the collected data demonstrates a trend toward sediment enrichment within the vicinity of the farm. These data are of interest to stakeholders concerned with the expansion of offshore aquaculture in the United States and other countries. To our knowledge, this is the first report of its kind from a commercially scaled aquaculture facility utilizing offshore submersible‐cage technologies.  相似文献   

Inhibition profile of trifludimoxazin towards PPO2 target site mutations     

Aimone Porri  Michael Betz  Kathryn Seebruck  Michael Knapp  Philipp Johnen  Matthias Witschel  Raphael Aponte  Rex Liebl  Patrick J. Tranel  Jens Lerchl 《Pest management science》2023,79(2):507-519

BACKGROUND

Target site resistance to herbicides that inhibit protoporphyrinogen IX oxidase (PPO; EC 1.3.3.4) has been described mainly in broadleaf weeds based on mutations in the gene designated protoporphyrinogen oxidase 2 (PPO2) and in one monocot weed species in protoporphyrinogen oxidase 1 (PPO1). To control PPO target site resistant weeds in future it is important to design new PPO-inhibiting herbicides that can control problematic weeds expressing mutant PPO enzymes. In this study, we assessed the efficacy of a new triazinone-type inhibitor, trifludimoxazin, to inhibit PPO2 enzymes carrying target site mutations in comparison with three widely used PPO-inhibiting herbicides.

RESULTS

Mutated Amaranthus spp. PPO2 enzymes were expressed in Escherichia coli, purified and measured biochemically for activity and inhibition kinetics, and used for complementation experiments in an E. coli hemG mutant that lacks the corresponding microbial PPO gene function. In addition, we used ectopic expression in Arabidopsis and structural PPO protein modeling to support the enzyme inhibition study. The generated data strongly suggest that trifludimoxazin is a strong inhibitor both at the enzyme level and in transgenics Arabidopsis ectopically expressing PPO2 target site mutations.

CONCLUSION

Trifludimoxazin is a potent PPO-inhibiting herbicide that inhibits various PPO2 enzymes carrying target site mutations and could be used as a chemical-based control strategy to mitigate the widespread occurrence of PPO target site resistance as well as weeds that have evolved resistance to other herbicide mode of actions. © 2022 BASF SE and The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

Personal and location-specific characteristics and elderly interstate migration     

Clark DE  Knapp TA  White NE 《Growth and change》1996,27(3):327-351

"The purpose of this paper is to investigate the impact of locational and individual characteristics upon interstate retiree migration, particularly in state-level public policy variables. Data regarding the characteristics of individual movers are drawn from the 1990 U.S. Census of Population and Housing 5% Public Use Microdata Sample. The household data are merged with location-specific attributes including both natural amenities and local fiscal variables." Three alternative models are developed, involving push factors, pull factors, and differences in site characteristics experienced by migrants. "The results indicate that both personal and locational characteristics are important factors determining the decision of elderly migrants to change their state of residence. While there is some limited support for the push and pull specifications, the difference model is found to provide the best overall fit."  相似文献   

An Assessment of State-and-Transition Models: Perceptions Following Two Decades of Development and Implementation     

Corrine N. Knapp  Maria E. Fernandez-Gimenez  David D. Briske  Brandon T. Bestelmeyer  X. Ben Wu 《Strength and Conditioning Journal》2011,64(6):598-606

State-and-transition models (STMs) are being developed for many areas in the United States and represent an important tool for assessing and managing public and private rangelands. Substantial resources have been invested in model development, yet minimal efforts have been made to evaluate the utility of STMs for rangeland assessment and management. We interviewed 47 rangeland professionals, equally divided between managers and researchers, in four ecoregions to determine their perceptions of the purpose, development, and strengths and weaknesses of STMs to assess the status of the STM framework. Our analysis identified three primary perspectives regarding the purpose of STMs: a decision-making tool for land managers, a means to represent the complex dynamics of rangeland ecosystems, and an effective communication tool. These diverse views of STM purposes were associated with differing perspectives concerning model development that identified five major issues in need of further development and refinement: 1) the relative importance of management practices and ecological processes in driving transitions, 2) the criteria used to define thresholds, 3) the appropriate level of model complexity, 4) the respective roles of expert knowledge and ecological data in model development, and 5) processes for model review and revision. We recommend greater dialogue among researchers and managers to further clarify STM terminology and develop standard protocols for model development and validation. Mechanisms are critically needed to assure peer review and revision of existing models so that STMs are continually updated to reflect current understanding of rangeland dynamics.  相似文献   

Assessment of urinary 15-F2-isoprostanes in dogs with urothelial carcinoma of the urinary bladder and other lower urinary tract diseases     

Andrew D. Woolcock  Adrienne Cheney  Pierre Deshuillers  Deborah Knapp  George E. Moore 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(6):2454-2459

  相似文献   

Establishing the need for an engineering standard for agricultural hitch pins     

Deboy GR  Knapp WM  Field WE  Krutz GW  Corum CL 《Journal of agricultural safety and health》2012,18(2):141-154

Documented incidents have occurred in which failure or unintentional disengagement of agricultural hitch pins has contributed to property damage and personal injury. An examination of current hitch pin use on a convenience sample of farm operations in Indiana revealed a variety of non-standard, worn and damaged, and inappropriately sized hitch pins in use. Informal interviews with the farm operators confirmed that hitch pin misuse, failure, or disengagement is a relatively widespread problem that remains largely unaddressed. On-site observations also suggested a low use of hitch pin retaining devices or safety chains. A review of prior research revealed that little attention has been given to this problem, and currently no documentation allows for an estimate of the frequency or severity of losses associated with hitch pin misuse, failure, or disengagement. No specific engineering standards were found that directly applied to the design, appropriate selection, or loading capacity of agricultural hitch pins. Major suppliers of replacement hitch pins currently provide little or no information on matching hitch pin size to intended applications, and most replacement hitch pins examined were of foreign origin, with the overwhelming majority imported from China or India. These replacement hitch pins provided no specifications other than diameter, length, and, in some cases, labeling that indicated that the pins had been "heat treated. " Testing of a sample of 11 commercially available replacement hitch pins found variation along the length of the pin shaft and between individual pins in surface hardness, a potential predictor of pin failure. Examination of 17 commercially available replacement pins also revealed a variety of identifiers used to describe pin composition and fabrication methods, e.g., "heat treated." None of the pins examined provided any specifications on loading capacity. It was therefore concluded that there is a need to develop an agricultural hitch pin engineering standard that would reflect current agricultural applications and practices and that would be promoted to both original equipment manufacturers and manufacturers and suppliers of replacement hitch pins. The standard should address the design of composite pins, heat treating, surface hardening, loading capacity and labeling of such, incorporation of unintentional disengagement prevention devices, indicators of the need for replacement due to wear, and safety information that should be included in operator instructions. ASABE is the most appropriate organization to develop such a standard. It was also concluded that agricultural safety and health programs and professionals need to raise the awareness of farmers concerning the appropriate selection and use of agricultural hitch pins, including the need to replace non-standard pins with pins less likely to fail or disengage during use, the need to replace hitch pins with indications of potential failure, and the importance of using appropriate safety chains, especially during transport of equipment behind tractors and trucks on public roads.  相似文献