Research in remote sensing of vegetation

The research topics undertaken were primarily selected to further the understanding of fundamental relationships between electromagnetic energy measured from Earth orbiting satellites and terrestrial features, principally vegetation. Vegetation is an essential component in the soil formation process and the major factor in protecting and holding soil in place. Vegetation plays key roles in hydrological and nutrient cycles. Awareness of improvement or deterioration in the capacity of vegetation and the trends that those changes may indicate are, therefore, critical detections to make. A study of the relationships requires consideration of the various portions of the electromagnetic spectrum; characteristics of detector system; synergism that may be achieved by merging data from two or more detector systems or multiple dates of data; and vegetational characteristics. The vegetation of Oregon is sufficiently diverse as to provide ample opportunity to investigate the relationships suggested above several vegetation types

Methodology for cuticular identification of selected eastern Oregon range plants

Animal dietary preferences have been studied by feeding-site examinations, animal observation, and stomach and esophageal collections. Analysis of fecal material for undigested plant cuticle is another means for obtaining the same information. This study was conducted to: (1) prepare a microscope slide series depicting the surface features of leaves and current annual growth of stems of selected plants, (2) evaluate methods for preparing plant and fecal material for cuticle examination, and (3) develop a key for identification of these plant surfaces. Plants were collected and identified by personnel of the PNW Forest and Range Experiment Station. All other work was conducted at Oregon State University, Corvallis, Oregon. Reference slides were prepared by three techniques: scraping, maceration and replication. All were appropriate for fresh or herbarium plant material. Scraping was a tedious method which provided pieces of cuticle representing the surface where other methods were unsuitable. Maceration yielded cuticle fragments strong enough to withstand the acid treatment, but was not adaptable to some plant surfaces. Replication techniques were easiest, but only half of the plant surfaces were acceptably represented in this manner and these caused additional problems during photomicrography. Fecal material was prepared for analysis by a macerating technique. Photomicrographs of reference slides were prepared for use in subsequent key development. Pictures were taken with a Makam camera mounted on a Wild M20 binocular microscope equipped with photo tube, using Kodak Contrast Process Panchromatic 3-1/4 x 4-1/4 sheet film. The key was developed using epidermal cell arrangement, trichome characteristics, stomata subsidiary cell arrangement, and silica bodies as dependable characters. Secondary characters included hair lengths, stomata size and cell outline. Differential digestion attributable to plant and (or) animal differences is a variable in analyzing cuticle fragments in fecal material not tested in this study. However, the key, a first approximation to cuticular identification of these selected plants, appears to handle this variability for most species studied. Successful use of the key is dependent upon a comprehensive assessment of the vegetation in the study area and the biology of the animal under study. This perspective is necessary to restrict the variables which would otherwise decrease the effectiveness of identification of cuticular fragments in fecal material

Do Incretins Play a Role in the Remission of Type 2 Diabetes after Gastric Bypass Surgery: What are the Evidence?

Gastric bypass surgery (GBP), in addition to weight loss, results in dramatic remission of type 2 diabetes (T2DM). The mechanisms by which this remission occurs are unclear. Besides weight loss and caloric restriction, the changes in gut hormones that occur after GBP are increasingly gaining recognition as key players in glucose control. Incretins are gut peptides that stimulate insulin secretion postprandially; the levels of these hormones, particularly glucagon-like peptide-1, increase after GBP in response to nutrient stimulation. Whether these changes are causal to changes in glucose homeostasis remain to be determined. The purpose of this review is to assess the evidence on incretin changes and T2DM remission after GBP, and the possible mechanisms by which these changes occur. Our goals are to provide a thorough update on this field of research so that recommendations for future research and criteria for bariatric surgery can be evaluated