24,854 research outputs found
Evaluation of AIS Data for Agronomic and Rangeland Vegetation: Preliminary Results for August 1984 Flight over Nebraska Sandhills Agricultural Laboratory
Since 1978 scientists from the Center for Agricultural Meteorology and Climatology at the University of Nebraska have been conducting research at the Sandhills Agricultural Laboratory on the effects of water stress on crop growth, development and yield using remote sensing techniques. We have been working to develop techniques, both remote and ground-based, to monitor water stress, phenological development, leaf area, phytomass production and grain yields of corn, soybeans and sorghum. Because of the sandy soils and relatively low rainfall at the site it is an excellent location to study water stress without the necessity of installing expensive rainout shelters. The primary objectives of research with the airborne imaging spectrometer (AIS) data collected during an August 1984 flight over the Sandhills Agricultural Laboratory are to evaluate the potential of using AIS to: (1) discriminate crop type; (2) to detect subtle architectural differences that exist among different cultivars or hybrids of agronomic crops; (3) to detect and quantify, if possible, the level of water stress imposed on the crops; and (4) to evaluate leaf area and biomass differences for different crops
Laboratory studies in ultraviolet solar physics
The research activity comprised the measurement of basic atomic processes and parameters which relate directly to the interpretation of solar ultraviolet observations and to the development of comprehensive models of the component structures of the solar atmosphere. The research was specifically directed towards providing the relevant atomic data needed to perform and to improve solar diagnostic techniques which probe active and quiet portions of the solar chromosphere, the transition zone, the inner corona, and the solar wind acceleration regions of the extended corona. The accuracy with which the physical conditions in these structures can be determined depends directly on the accuracy and completeness of the atomic and molecular data. These laboratory data are used to support the analysis programs of past and current solar observations (e.g., the Orbiting solar Observatories, the Solar Maximum Mission, the Skylab Apollo Telescope Mount, and the Naval Research Laboratory's rocket-borne High Resolution Telescope and Spectrograph). In addition, we attempted to anticipate the needs of future space-borne solar studies such as from the joint ESA/NASA Solar and Heliospheric Observatory (SOHO) spacecraft. Our laboratory activities stressed two categories of study: (1) the measurement of absolute rate coefficients for dielectronic recombination and electron impact excitation; and (2) the measurement of atomic transition probabilities for solar density diagnostics. A brief summary of the research activity is provided
Developing flamingo husbandry practices through workshop communication
ArticleZoos are duty-bound to provide excellent welfare standards for the species that they keep. Curators and keepers have a role to play in ensuring that husbandry regimes are relevant and mimic a species’ natural environment. This paper explains the key outcomes from ABWAK’s (Association of British and Irish Wild Animal Keepers) first national flamingo keepers’ workshop. Research on flamingo breeding is well documented in the literature, but research into other aspects of husbandry may develop flamingo welfare further. By engaging keepers and academics with a direct influence over flamingo management, questions relating to best practice can be answered to establish areas of common good practice as well as novel approaches. Topics presented for discussion at the workshop focused on 1) informed enclosure design, 2) relevant enrichment ideas and 3) "promotion" of flamingos to the zoo visitor, with the aim of having a positive impact on the birds’ quality of life and their value as a zoo exhibit. Outcomes generated included the development of enrichment and husbandry modifications that may enhance flamingo activity patterns and their display to zoo visitors. Many aspects of regular flamingo husbandry can have an enriching influence on the birds’ lives, therefore encouraging zoo professionals to share ideas may benefit many flamingos in many zoos. Through the medium of a workshop, husbandry techniques for specialist species such as the flamingo can be shared and developed
Researching creatively with pupils in Assessment for Learning (AfL) classrooms on experiences of participation and consultation
This paper reports on an ESRC TLRP project, Consulting Pupils on the Assessment of their Learning (CPAL). The CPAL project provides an additional theoretical perspective to the ‘educational benefits’ perspective of engaging pupil voice in learning and teaching (Rudduck et al., 2003) through its exploration of pupil rights specifically in relation to assessment issues presently on the policy agenda in the Northern Ireland context – notably Assessment for Learning (AfL). An emergent framework for assessing pupil rights, based on Article 12 of the United Nations Convention on the Rights of the Child (Lundy, 2007), is being used to explore the ways in which AfL classroom practice creates the conditions for increased pupil participation and consultation. Pupil views on their AfL classroom experiences and participation are explored by means of a variety of pupil-centred, creative research methods that engage and stimulate pupils to observe, communicate and analyse their learning and assessment experiences and give meaning to them. This presentation highlights preliminary data based on a sample of 11-14 years pupils' experiences of participation and consultation in classrooms adopting AfL pedagogical principles, and identifies characteristics that support or inhibit pupil participation in their learning and the expression of their views about such matters
Absence of anomalous negative lattice-expansion for polycrystalline sample of Tb2Ti2O7
High resolution X-ray powder-diffraction experiments on a well-characterized
polycrystalline sample of the spin liquid Tb2Ti2O7 reveal that it shows normal
positive thermal-expansion above 4 K, which does not agree with the intriguing
anomalous negative thermal-expansion due to a magneto-elastic coupling reported
for a single crystal sample below 20 K. We also performed a Rietveld profile
refinement of a powder-diffraction pattern taken at a room temperature, and
confirmed that it is consistent with the fully ordered cubic pyrochlore
structure.Comment: 2 pages, 3 figure
Análise de investimento de programas de melhoramento de pastagem para a produção de gado de corte no Cerrado.
Descrição do modelo. Suposições referentes ao sistema tradicional. Estrutura do modelo. Dados. Validação. Programa de computador. Experimentação. Resultados e discussão. Proporção de pastagem melhorada na fazenda e idade de venda de macho. Taxa de estabelecimento da pastagem cultivada. Método para aumentar o numero de vacas de cria. Método para aumentar o tamanho do rebanho. Compra de vacas velhas para engordar durante a estação chuvosa. Prioridade para o uso da pastagem melhorada.bitstream/item/104671/1/Analise-de-investimento-de-programas.pd
A quest for frustration driven distortion in Y2Mo2O7
We investigated the nature of the freezing in the geometrically frustrated
Heisenberg spin-glass Y2Mo2O7 by measuring the temperature dependence of the
static internal magnetic field distribution above the spin-glass temperature,
Tg, using the muSR technique. The evolution of the field distribution cannot be
explained by changes in the spin susceptibility alone and suggests a lattice
deformation. This possibility is addressed by numerical simulations of the
Heisenberg Hamiltonian with magneto-elastic coupling at T>0.Comment: 5 pages 4 figures. Accepted for publication in PR
The taxonomic status of \u3cem\u3eSturnira bidens\u3c/em\u3e (Chiroptera: Phyllostomidae) with notes on its karyotype and life history
Reliability assessment of design rules for stainless steel structures
This paper presents a re-evaluation of the current partial resistance factors recommended in EN 1993-1-4 for the design of stainless steel elements. Material data from key stainless steel producers were collected and carefully analysed, and representative values of the over-strength and the coefficient of variation (COV) of the material yield strength and ultimate tensile strength, necessary for performing reliability analysis, were established. The EN 1990 Annex D First Order Reliability Method (FORM) was applied to a substantial pool of experimental results. At the cross-section level, stub column and in-plane bending test results were used to assess the γM0 partial resistance factor. At the member level, flexural buckling and lateral-torsional buckling test results were used to evaluate the γM1 partial resistance factor. It is revealed that the current recommended partial resistance factors in EN 1993-1-4 (γM0 = γM1 = 1.1) cannot generally be reduced, and in some cases, modified design resistance equations are required, if the current safety factors are to be maintained
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