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Full-Text Articles in Life Sciences

Dust Emissions From Undisturbed And Disturbed, Crusted Playa Surfaces: Cattle Trampling Effect, Ed Frederickson, Teddy Zobeck, Matthew Baddock, Robert Van Pelt Dec 2009

Dust Emissions From Undisturbed And Disturbed, Crusted Playa Surfaces: Cattle Trampling Effect, Ed Frederickson, Teddy Zobeck, Matthew Baddock, Robert Van Pelt

Ed L. Frederickson

Dry playa lake beds can be a significant source of fine dust emissions during high wind events in arid and semiarid landscapes. The physical and chemical properties of the playa surface control the amount and properties of the dust emitted. In this study, we use a field wind tunnel to quantify the dust emissions from a bare, fine-textured playa surface located in the Chihuahua Desert at the Jornada Experimental Range, near Las Cruces, New Mexico, USA. We tested natural, undisturbed crusted surfaces and surfaces that had been subjected to two levels of domestic animal disturbance. The animal disturbance was provided …


Effect Of External Energy On Atomic, Crystalline And Powder Characteristics Of Antimony And Bismuth Powders, Mahendra Kumar Trivedi, Vikram V. Dabhade, Rama Mohan Tallapragada Sep 2009

Effect Of External Energy On Atomic, Crystalline And Powder Characteristics Of Antimony And Bismuth Powders, Mahendra Kumar Trivedi, Vikram V. Dabhade, Rama Mohan Tallapragada

Mahendra Kumar Trivedi

Next to atoms and molecules the powders are the smallest state of matter available in high purities and large quantities. The effect of any external energy on the shape, morphology and structure can thus be studied with relative ease. The present investigation deals with the effect of a non-contact external energy on the powders of antimony and bismuth. The characteristics of powders treated by external energy are com-pared with the as received powders (control). The average particle sizes, d50 and d99, the sizes below which 99% of the particles are present showed significant increase and decrease indicating that the energy …


Colorado Potato Beetle Management On Potatoes: Current Challenges And Future Prospects., Andrei Alyokhin Dec 2008

Colorado Potato Beetle Management On Potatoes: Current Challenges And Future Prospects., Andrei Alyokhin

Andrei Alyokhin

The Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) is the most important insect defoliator of potatoes that can completely destroy potato crops. Its current range covers about 16 million km2 in North America, Europe, and Asia and continues to expand. A complex and diverse life history, combined with an impressive ability to develop insecticide resistance, make the Colorado potato beetle a challenging pest to manage. Beetle populations on commercial farms are usually suppressed by insecticides, which are likely to remain the predominant approach for the foreseeable future. In addition, the beetles can be controlled through the use of relatively …


A Retention Index Calculator Simplifies Identification Of Plant Volatile Organic Compounds, Ed Frederickson Dec 2008

A Retention Index Calculator Simplifies Identification Of Plant Volatile Organic Compounds, Ed Frederickson

Ed L. Frederickson

Plant volatiles (PVOCs) are important targets for studies in natural products, chemotaxonomy and biochemical ecology. The complexity of PVOC profiles often limits research to studies targeting only easily identified compounds. With the availability of mass spectral libraries and recent growth of retention index (RI) libraries, PVOC identification can be achieved using only gas chromatography coupled to mass spectrometry (GCMS). However, RI library searching is not typically automated, and until recently, RI libraries were both limited in scope and costly to obtain. Objective To automate RI calculation and lookup functions commonly utilised in PVOC analysis. Methodology Formulae required for calculating retention …


Grassland In The Borderlands: Understanding Coupled Natural Human Systems And Transboundary Conservation, Ed Frederickson, G. Ceballos, R. List, A. Davidson, Sierra Corona, L. Martinez, J.E. Herrick, J. Pacheco Dec 2008

Grassland In The Borderlands: Understanding Coupled Natural Human Systems And Transboundary Conservation, Ed Frederickson, G. Ceballos, R. List, A. Davidson, Sierra Corona, L. Martinez, J.E. Herrick, J. Pacheco

Ed L. Frederickson

As conservationists well know, political borders rarely coincide with natural ecological boundaries. International borders such as that between the United States and Mexico traverse numerous ecosystems and watersheds. Many species of animals, birds, and insects regularly migrate between habitats across international borders. Conservation of Shared Environments collects works that take on the environmental issues along the U.S.-Mexico border. Covering topics as diverse as wildlife preservation, grassland ecology, water rights, indigenous peoples, and the ecological consequences of border security, the contributors to this volume offer not only scientific analysis but also insight on how to bridge the gaps between scientists, policy …


Stimulatory And Suppressive Effects Of Novaluron On The Colorado Potato Beetle Reproduction., Andrei Alyokhin, Ryan Guillemette, Raymond Choban Dec 2008

Stimulatory And Suppressive Effects Of Novaluron On The Colorado Potato Beetle Reproduction., Andrei Alyokhin, Ryan Guillemette, Raymond Choban

Andrei Alyokhin

The Colorado potato beetle, Leptinotarsa decemlineata (Say), is one of the most damaging insect pests of potato. Novaluron is a relatively new benzoylphenyl urea insect growth regulator with good activity against this pest. Earlier studies revealed that feeding on potato foliage treated with novaluron induces reversible egg hatch inhibition in adult Colorado potato beetles. We investigated if novaluron effects depend on physiological state of the beetles at the time of exposure. The following four treatments were created: young beetles unmated at the beginning of the experiment and feeding on potato foliage treated with novaluron, young beetles unmated at the beginning …


Interactions Of Native And Non-Native Lady Beetle Species (Coleoptera: Coccinellidae) With Aphid-Tending Ants In Laboratory Arenas, Christy Finlayson, Andrei Alyokhin, Erin Porter Dec 2008

Interactions Of Native And Non-Native Lady Beetle Species (Coleoptera: Coccinellidae) With Aphid-Tending Ants In Laboratory Arenas, Christy Finlayson, Andrei Alyokhin, Erin Porter

Andrei Alyokhin

Interactions between lady beetles and the European fire ant (Myrmica rubra L.) tending potato aphids [Macrosiphum euphorbiae (Thomas)] were compared in the laboratory. Lady beetle species native to North America (Coccinella trifasciata perplexa Mulsant, Coleomegilla maculata lengi Timberlake, Hippodamia convergens Guerin-Meneville) and non-native species of Palearctic origin [Coccinella septempunctata L., Harmonia axyridis (Pallas), Hippodamia variegata (Goeze), Propylea quatuordecimpunctata L.)] were evaluated. Harmonia axyridis consumed a significantly greater number of aphids compared with all other species but C. septempunctata. Ant stings affected H. variegata and C. septempunctata to a greater extent than other species. Ants showed a significantly greater amount of …