North American Research Papers - Academia.edu (original) (raw)

Purpose – To draw the frontiers of the functional food universe, to identify concepts that should be included in a broadly accepted functional food definition and to propose a definition. Design/methodology/approach – Based on a review of... more

Purpose – To draw the frontiers of the functional food universe, to identify concepts that should be included in a broadly accepted functional food definition and to propose a definition. Design/methodology/approach – Based on a review of the literature and the Delphi technique with a group of North American and European experts. Findings – Four concepts were identified: the nature

Over the past decade, Web-based learning management systems, such as Blackboard and WebCT, have been gradually integrated into college education. The strategic use and effectiveness of such systems have been investigated to a large... more

Over the past decade, Web-based learning management systems, such as Blackboard and WebCT, have been gradually integrated into college education. The strategic use and effectiveness of such systems have been investigated to a large extent. What is less covered is what students really think about such learning management systems. Understanding students' evaluations can shed light on the development, selection, training, maintenance, use, and investment on such systems. In this paper, we report a longitudinal ...

For various reasons, North American crop farmers are more likely to practice limited-duration no-till than continuous no-till (NT). Little is known about effects of short-term no-till (ST-NT) on organic C and total N relative to NT and... more

For various reasons, North American crop farmers are more likely to practice limited-duration no-till than continuous no-till (NT). Little is known about effects of short-term no-till (ST-NT) on organic C and total N relative to NT and conventional-till systems. A field experi- ment was initiated in 1980 to study the effects of NT, chisel plow (CP), and moldboard plow in

The subspecies composition of migratory sandhill cranes (Grus canadensis) which stage and winter along the Lower Columbia River in northwest Oregon and southwest Washington is uncertain, but may include all 3 using the Pacific Flyway:... more

The subspecies composition of migratory sandhill cranes (Grus canadensis) which stage and winter along the Lower Columbia River in northwest Oregon and southwest Washington is uncertain, but may include all 3 using the Pacific Flyway: lesser (G. c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). However, the status of rowani has been debated. During 2001-02, we captured and marked 8 cranes using a noose line trapping technique, and attached Platform Transmitter Terminals (PTTs) to 6 to ascertain locations of their breeding areas, migration corridors and winter sites. Morphometric data were collected for subspecies determination. From measurements and their summer distribution, we conclude that they are likely the intermediate rowani form. Because of their limited numbers, distinct coastal migration path, and habitat issues at breeding, staging, and wintering areas, we recommend that conservation efforts be increased and that they be managed as a unique population. ...

The Romeral Fault System (RFS) extends 1600 km from Barranquilla-Colombia to Talara city-Peru and before the Pliocene. In the Middle Eocene RFS defi ned the northwestern border of the South America plate, being originated by a triple... more

The Romeral Fault System (RFS) extends 1600 km from Barranquilla-Colombia to Talara city-Peru and before the Pliocene. In the Middle Eocene RFS defi ned the northwestern border of the South America plate, being originated by a triple junction rift- rift- rift occurred from lower to middle Jurassic, when the South American sector separated from Chortis, Oaxaca and Yucatan blocks. From Late Mesozoic until Early Paleocene, the Paleo Pacifi c plate converged on NW South America corner being subducted when an anomalous thick oceanic crust, represented by the Caribbean plate, was accreted extinguishing gradually from the North of Peru to the North of Colombia. The collision generated a transtensive fi eld stress in back arc region, due to the ancestral Central Cordillera rising in continental border. The RFS rocks suffered low grade metamorphism and some rocks of extinct subduction zone suffered metamorphic inversion. During Late Paleogene until Early Miocene, the convergence South Americ...

Prostate cancer is the most common cancer in North American men. Currently available prognostic factors inadequately predict which cancers will be aggressive and which will lead an indolent course. This study was aimed at investigating... more

Prostate cancer is the most common cancer in North American men. Currently available prognostic factors inadequately predict which cancers will be aggressive and which will lead an indolent course. This study was aimed at investigating the role of matrix metalloproteinase (MMP)-2 in prostate cancer disease-free survival. We correlated MMP-2 expression by malignant prostatic epithelium and stromal cells with prostate cancer disease-free survival in 187 stage pT3NxM0 prostate carcinomas using immunohistochemistry. MMP-2 was expressed by cancer cells in 131 cases (70.0%) and by stromal cells in 142 cases (75.9%). MMP-2 expression by stromal cells was not associated with progression (P = 0.7270). However, in multivariate analyses, adjusting for the Gleason score, tumor-node-metastasis stage, and initial serum prostate-specific antigen, MMP-2 expression by >50% of malignant epithelial cells was associated with decreased disease-free survival (hazard ratio, 4.267; P = 0.0012). Increase...

Boreal forest carbon (C) storage and sequestration is a critical element for global C management and is largely disturbance driven. The disturbance regime can be natural or anthropogenic with varying intensity and frequency that differ... more

Boreal forest carbon (C) storage and sequestration is a critical element for global C management and is largely disturbance driven. The disturbance regime can be natural or anthropogenic with varying intensity and frequency that differ temporally and spatially the boreal forest. The objective of this review was to synthesize the literature on C dynamics of North American boreal forests after most common disturbances, stand replacing wildfire and clearcut logging. Forest ecosystem C is stored in four major pools: live biomass, dead biomass, organic soil horizons, and mineral soil. Carbon cycling among these pools is inter-related and largely determined by disturbance type and time since disturbance. Following a stand replacing disturbance, (1) live biomass increases rapidly leading to the maximal biomass stage, then stabilizes or slightly declines at old-growth or gap dynamics stage at which late-successional tree species dominate the stand; (2) dead woody material carbon generally follows a U-shaped pattern during succession; (3) forest floor carbon increases throughout stand development; and (4) mineral soil carbon appears to be more or less stable throughout stand development. Wildfire and harvesting differ in many ways, fire being more of a chemical and harvesting a mechanical disturbance. Fire consumes forest floor and small live vegetation and foliage, whereas logging removes large stems. Overall, the effects of the two disturbances on C dynamics in boreal forest are poorly understood. There is also a scarcity of literature dealing with C dynamics of plant coarse and fine roots, understory vegetation, small-sized and buried dead material, forest floor, and mineral soil.

In this chapter, we review empirical evidence for stronger allelopathic effects of exotic European invaders on North American natives than on other European species. We argue that this evidence provides critical insights into the impor-... more

In this chapter, we review empirical evidence for stronger allelopathic effects of exotic European invaders on North American natives than on other European species. We argue that this evidence provides critical insights into the impor- tance of coevolutionary relationships within plant communities. We discuss how the disruption of these and other biochemical coevolutionary relation- ships may lead to the success