Role of Competition in Restoring Resource Poor Arid Systems Dominated by Invasive Grasses

An understanding of competition intensity and importance may be a useful step in helping managers understands how to prioritize restoration efforts in resource poor environments within the semi-arid steppe. The aims of this study were to quantify the intensity of competition among invasive annual grasses and native perennial bunchgrasses, and determine the importance of competition in explaining variation in target plant biomass and survivorship in a Wyoming big sagebrush steppe community type in southeastern Oregon, USA. Addition series experiments were conducted in 2008 and 2009 among four species. Treatments consisted of monoculture densities of each species to assess intraspecific competition, and mixtures of two, three and four species (interspecific competition), producing varying total densities and species proportions. We found no evidence that intensity of intra- or inter-specific competition were significant for the first two years species were establishing, regardless of the density used as the independent variable. Our results indicate that neither the intensity of competition nor the importance of competition explained variation in target plant biomass and survivorship for the first two years plants were establishing. Instead abiotic factors may have an overriding influence on plant biomass and survivorship.We propose four scenarios which may apply to semi-arid environments during the initial phase of restoration

Foliage applications of terbacil to peppermint (Mentha piperita) and several weed species

Several studies were conducted to determine the feasibility of using terbacil (3-tert-butyl-5-chloro-6-methyluracil) postemergence to weeds and peppermint (Mentha piperita L.). Three nonionic surfactants, four nonphytotoxic oils, and a liquid fertilizer were each combined with 0.5 lb ai/A terbacil in 35 gallons of water per acre. Weed species tested include: redroot pigweed (Amaranthus retroflexus L.), lambsquarters (Chenopodium album L.), common mustard (Brassica campestris L.), barnyardgrass (Echinochloa crusgalli (L.) Beauv.), and green foxtail (Setaria viridis (L.) Beauv.). Broadleaf weeds were more susceptible to foliage applications of terbacil than grass species. However, excellent control of both broadleaf weeds and grasses was obtained when applications were made within seven days after weed seedling emergence. Less grass control always resulted when treatments were made two or three weeks after emergence. The addition of nonphytotoxic oils or surfactants to the spray solution was beneficial to terbacil activity at later stages of weed growth. Nonphytotoxic oils were usually more effective than surfactants. Solution 32, a liquid nitrogen solution, in combination with terbacil did not improve herbicidal activity. None of the terbacil treatments with or without spray solution additives, significantly reduced peppermint hay production. Bioassay of core samples to determine the amount of herbicide remaining in soil from preemergence and split applications of terbacil indicated that lower levels of herbicide remained in soils treated by split application. Foliage interception and subsequent rapid detoxification of terbacil by the peppermint plant may explain this observed decrease of herbicide in the soil

Systematic design of legal regulations for optimal surface-groundwater usage - Phase 2

Includes bibliographical references.September 1975.To view the abstract, please see the full text of the document.OWRT Project no. B-109-Co1orado, Period July 1, 1973 - September 30, 1975; partly funded by U.S. Office of Water Resources Research, project no. B-076-Colorado, agreement no.14-31-0001-3866

College student's academic goals and learning strategies

Tomando en cuenta que no existe concordancia en la literatura entre los resultados de diferentes estudios respecto de la relevancia de la adopción de un tipo u otro de meta para el aprendizaje académico, en el presente artículo se estudia la relación entre los diferentes tipos de orientaciones motivacionales (metas de aprendizaje, metas de rendimiento y metas de evitación del trabajo) y el uso de estrategias cognitivas y de autorregulación. En el trabajo participan 632 estudiantes universitarios de diversas titulaciones de la universidad española. Aunque el estudio es de tipo correlacional, los análisis de los datos obtenidos, corroborando estudios anteriores, aportan información de interés para la discusión del problema que se investigó, por ejemplo que sólo los niveles más altos de metas de aprendizaje se encuentran asociados con una mayor utilización de estrategias de aprendizaje. Son discutidas implicaciones educativas de estos datos.Tomando em consideração que não existe concordância na literatura entre os resultados dos diferentes estudos a respeito da relevância da adopção de um ou de outro tipo de meta na aprendizagem académica; no presente artículo é estudada a relação entre os diferentes tipos de orientações motivacionais (metas de aprendizagem, metas de rendimento e metas de evitação do trabalho) e a utilização de estratégias cognitivas e de autoregulação. Neste trabalho participam 632 estudantes universitários de diversas licenciaturas da Universidade espanhola. Apesar de este estudo ser de tipo correlacional, a análise dos dados obtidos, corroborando estudos anteriores, aporta informação de interesse para a discussão do problema investigado; por exemplo que só os níveles mais altos de metas de aprendizagem se encontram associados con uma maior utilização de estratégias de aprendizagem. São discutidas implicações educativas destes dados.Assuming that there isn’t much agreement among the results from different studies relating to the relevance of adopting one or another kind of academic learning goal, this paper intends to study the relationship between the several types of motivational orientations (learning goals, achievement goals and avoidance goals) and the use of cognitive and self-regulatory strategies. 632 Spanish college students from various university courses participated in this research. Although this is a correlacional study data analysis, in line with previous studies, brings to light interesting information and highlights the investigated issue for example only higher levels of learning goals are positively related with the use of learning strategies. Future educational implications are also discussed

Waterlogging control for improved water and land use efficiencies: a systematic analysis

Submitted to Office of Water Research and Technology, U.S. Dept. of the Interior; December 1980.Bibliography: pages 135-138.OWRT project 14-34-0001-6211-C-7144

Is It the Company's or Mine? Perceived Organizational Justice Practices and the Ownership of Job Knowledge

This study examined the factors that determine a workers willingness to share private knowledge gained on the job. The recent vogue in knowledge management studies typically assumes that workers naturally are willing to share what they have learned, but economic theory suggests that there should be powerful disincentives to share. We explored justice practices, individual personality, the psychological contract, organizational commitment and their relationships to worker ownership. Results indicated that procedural and distributive justice had opposite effects on knowledge ownership, while psychological contract breach and continuance commitment had positive, direct effects on knowledge ownership

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]