5,104 research outputs found
Spatial scales of cirrus cloud properties
Research in studying the spatial scales of the cirrus, used data collected during the flight legs of the NCAR Sabreliner aircraft on four days during the FIRE Cirrus IFO to study the spatial scales of the cirrus, and will concentrate on the scales of horizontal wind. The spatial scales of the cloud features can be described by power spectra (or spectral density graphs) and cumulative variance graphs. The cumulative variance graphs were created by first using a Fast Fourier Transform (FFT) to create variance spectra. The variances were then summed in a cumulative fashion from the largest scalelengths (wavelengths) to the smallest. No detrending was done to the original data, and no smoothing or averaging was done to the spectral points. All the spectral points were included. This means that the values of the first five to ten spectral points of the large scalelengths should only be considered to be qualitatively correct. The cumulative variance at smaller scalelengths should be correct because a more accurate representation of the variance at the larger scalelengths should only redistribute the energy amongst the larger scalelengths
Utilization of solar energy in developing countries: Identifying some potential markets
The potential use of solar electricity generated from photovoltaic cells is examined for nineteen developing nations. Energy and economic profiles are summarized for each country. A comparison is made between the use of autogeneration and photovoltaics in a rural area of Haiti
A digital simulation of message traffic for natural disaster warning communications satellite
Various types of weather communications are required to alert industries and the general public about the impending occurrence of tornados, hurricanes, snowstorms, floods, etc. A natural disaster warning satellite system has been proposed for meeting the communications requirements of the National Oceanic and Atmospheric Administration. Message traffic for a communications satellite was simulated with a digital computer in order to determine the number of communications channels to meet system requirements. Poisson inputs are used for arrivals and an exponential distribution is used for service
A promising biotechnical approach to pest management of the western corn rootworm in Illinois maize fields shielded with a MCA kairomone baited trap line
The leaf beetle Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), (D.v.v.), also called the western corn rootworm, is endemic to the New World and ranks among the top ten insect pests in worldwide grain production. D.v.v. causes annual damages of 1 billion US Dollars and is a notoriously difficult insect pest to control and manage, as entomological history of the past 50 years amply demonstrates (METCALF 1986). Considering recent emphasis on environmentally compatible and sustainable management strategies, entomologists and practitioners are encouraged to pay increased attention to novel approaches such as biotechnial methods which today are characterized by preferential use of signal compounds. Fortunately, both insect and plants provide a wide variety of such natural resources. In the case of D.v.v., sex pheromonesand plant kairomones as specific attractants and management tools are relatively well investigated through numerous contributions by GUSS et al. (1982), METCALF & METCALF (1992), METCALF (1994) and many recent publications on the advance and spread of D.v.v. within Europe (BERGER 1995-2004, HUMMEL 2003). Principle of MSD method: In this paper, the plant kairomone 4-methoxycinnamaldehyde (MCA), a specific attractant for D.v.v., is being used as a tool within the newly proposed "MSD" strategy. It combines a two pronge approach consisting as the well known mass trapping with the novel shielding and deflecting, called in short "diversion" and introduced here for the first time. An invisible “curtain” or “fence” of MCA vapor released from a MCA trap line establishes a behavioral barrier which the flying beetles cannot easily pass without being 1. either caught in one of the high capacity traps or 2. being diverted elsewhere. The net effect is a significant reduction in adult population density and oviposition within the MCA treated field as compared to an untreated control field. These effects can be experimentally measured by 1. adult beetle counts on maize plants, 2. by counts in independent monitoring traps baited with the D.v.v. sex pheromone, and 3. by egg counts taken in soil samples.Umweltgerechter und nachhaltiger Pflanzenschutz erfordert eine Vielzahl verschiedener Strategien zum Management von Schadinsekten auf ihren Wirtspflanzen. Insekten- und pflanzeneigene Signalstoffe sowie ihre synthetischen Analoga bieten einen nahezu unerschöpflichen Vorrat spezifischer Lockwirkungen und Interventionsmöglichkeiten an, der bisher leider nur unzureichend genutzt wird. Kürzliche Entdeckungen sowohl neuer Kairomon-Lockstoffe als auch neuer Verfahrensschritte für das Management des Westlichen Maiswurzelbohrers Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) (D.v.v.) erweitern das Spektrum anwendbarer Management- Optionen für diesen schwer bekämpfbaren Schädling im nordamerikanischen Maisanbau. Seit seiner Einschleppung nach Europa (ČAMPRAG & BAČA 1995) wird D.v.v. neuerdings auch zunehmend zum Problemschädling an Mais in Europa. Die neue "MSD"-Technik besteht aus einer Kombination von Massenabfang ("mass trapping"), Abschirmung ("shielding") und Umlenkung ("diversion") der Blattkäfer. Fallen hoher Fangkapazität, die das Kairomon 4-Methoxyzimtaldehyd (MCA) und Cucurbitacin- Pulver als fraßfördernden Stoff enthalten, können bei Aufstellung als "Fallenzaun" relativ geringer Dichte die Käfer so umlenken, dass zwischen den beiden Seiten dieses Zauns eine unsichtbare Geruchs-Barriere entsteht. Diese führt zu einer messbaren und signifikanten Verminderung der Käferzahl zwischen MCA behandelten Feldabschnitten gegenüber ihren unbehandelten Kontrollen. In 0,27 ha bzw. 0,12 ha großen Maisversuchsfeldern der Standorte Urbana und Champaign des US-Staates Illinois ließen sich während der Monate August und September 2003 und 2004 nach MCA-Behandlung gegenüber Kontrollen deutliche und signifikante Verminderungen von D.v.v. an Hand dreier Kriterien nachweisen: 1. Käferzahlen auf Maispflanzen innerhalb des "MSD-Feldes", 2. Käferzahlen in Sexuallockstoff-Fallen im MSD Feld und 3. die Zahl abgelegter D.v.v.-Eier im Boden des MSD Feldes nehmen ab. Der beobachtete Effekt läßt sich nicht allein auf die Populationsverminderung infolge hoher Abfangzahlen zurückführen. Es gibt darüber hinaus einen Abschirm- und Umlenkeffekt, dessen sinnes- und verhaltensphysiologische Mechanismen zusätzliche künftige Erforschungen erforderlich machen
Mapping Ohio's Compassion
This report gives an overview of the state of the nonprofit sector in Ohio
Photovoltaic power systems for rural areas of developing countries
Systems technology, reliability, and present and projected costs of photovoltaic systems are discussed using data derived from NASA, Lewis Research Center experience with photovoltaic systems deployed with a variety of users. Operating systems in two villages, one in Upper Volta and the other in southwestern Arizona are described. Energy cost comparisons are presented for photovoltaic systems versus alternative energy sources. Based on present system technology, reliability, and costs, photovoltaics provides a realistic energy option for developing nations
"I Don't Like Ambiguity": An Exploration of Students' Experiences During a Qualitative Methods Course
Although some of the literature on teaching qualitative research methods courses has included students' experiences during courses, these experiences have not been made a primary focus of study and examined systematically. To gain a fuller understanding of students' experiences during a graduate-level qualitative methods course, 13 reflective journals were analyzed. Eight major categories emerged from the analysis: (a) struggling with a new paradigm, (b) changes in perspective on quantitative research, (c) struggling with phenomenological and other qualitative concepts and practices, (d) becoming more aware of one's role in the research process, (e) challenges faced during the research process, (f) gaining new insights into the research process, (g) gaining new insights into phenomenology and the qualitative paradigm, and (h) valuing phenomenological and other forms of qualitative research. Implications of the findings for designing and teaching qualitative methods courses are also discussed.Alors que certaines recherches portant sur l'enseignement des cours de méthodes de recherche qualitatives incluent les expériences vécues par les étudiants qui suivaient les cours, elles ne sont pas axées sur ces expériences et n'en ont pas fait l'objet d'étude systématique. Dans le but de mieux comprendre ce que vivaient les étudiants inscrits à un cours du deuxième cycle sur les méthodes qualitatives, nous avons analysé treize journaux à réflexions. Huit catégories principales sont ressorties de l'analyse: (a) la difficulté de saisir un nouveau paradigme, (b) les changements de perspective sur la recherche quantitative, (c) la difficulté de saisir des concepts et pratiques qualitatifs tels ceux phénoménologiques, (d) la conscientisation grandissante quant à son propre rôle dans le processus de recherche, (e) les défis s étant présentés pendant la recherche, (f) l'apprentissage de nouveaux concepts touchant la recherche, (g) l'apprentissage de nouveaux concepts en phénoménologie et le paradigme qualitatif et (h) la valorisation des types de recherche qualitative telle la recherche phénoménologique. Une discussion suit sur les implications des résultats pour la conception et l'enseignement de cours de méthodes qualitatives
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