199,293 research outputs found
Posible declinaci\uf3n poblacional de la mariposa Papilio polyxenes americus Kollar (Lepidoptera: Papilionidae) en el valle intra-andino de M\ue9rida, Venezuela
Get PDFOrellana A, Erazo M. 2002. Possible population decline of the
swallowtail Papilio polyxenes americus Kollar (Lepidoptera:
Papilionidae) in the intra-Andean valley of M\ue9rida, Venezuela.
Entomotropica 17(2):189-190. Since the second half of the 90's, the
swallowtail butterfly, Papilio polyxenes americus Kollar, 1859, a
formerly common species, has become scarce or may even be disappearing
from the Chama river basin of Andean M\ue9rida, Venezuela. No
concrete explanations are given for the fact, but it is presumed that
it may be linked to human activities, especially the use of pesticides.Orellana A, Erazo M. 2002. Posible declinaci\uf3n poblacional de la
mariposa Papilio polyxenes americus Kollar (Lepidoptera:
Papilionidae) en el valle intra-andino de M\ue9rida, Venezuela.
Entomotropica 17(2):189-190. A partir de la segunda mitad de los
a\uf1os 1990 Papilio polyxenes americus Kollar, 1850, anteriormente
com\ufan, parece estar desapareciendo de la zona media del r\uedo
Chama, en el estado andino de M\ue9rida, Venezuela. Esto se sustenta
en observaciones no sistem\ue1ticas, pero continuas. No se ofrecen
explicaciones concretas para esta disminuci\uf3n, pero pudiera estar
vinculada a actividades humanas, especialmente el uso de plaguicidas
Infrasound tornillos produced by Volcán Cotopaxi's deep crater
No full textWe characterize and interpret a new type of infrasound signal originating from the summit of Volcán Cotopaxi (Ecuador) that was primarily observed between September 2015 and March 2016, following the 2015 eruptive period. This infrasound waveform is a slowly decaying sinusoid with exceptional low-frequency (fp = 0.2 Hz) and high quality factor (Q = ~10) and resembles the shape of tornillo seismic waveforms. The repeating events, occurring about once per day in early 2016, are stable in frequency content, and we attribute them to excitation of a vertical-walled crater, with radius of about 125 m and length of 300 m. Spectral properties of the tornillo permit constraints on crater sound speed (335 m/s ± 6%) and temperature (4–32°C). The initial polarity of the tornillos is predominantly a rarefaction and could reflect repeating crater bottom collapse events (implosions) or explosion sources whose infrasound is heavily modulated by the crater's pipe-like geometry
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Posible declinación poblacional de la mariposa Papilio polyxenes americus Kollar (Lepidoptera: Papilionidae) en el valle intra-andino de Mérida, Venezuela
Get PDFOrellana A, Erazo M. 2002. Possible population decline of the
swallowtail Papilio polyxenes americus Kollar (Lepidoptera:
Papilionidae) in the intra-Andean valley of Mérida, Venezuela.
Entomotropica 17(2):189-190. Since the second half of the 90's, the
swallowtail butterfly, Papilio polyxenes americus Kollar, 1859, a
formerly common species, has become scarce or may even be disappearing
from the Chama river basin of Andean Mérida, Venezuela. No
concrete explanations are given for the fact, but it is presumed that
it may be linked to human activities, especially the use of pesticides
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Autocorrelation infrasound interferometry
No full textSeismic and infrasound multistation ambient-noise interferometry has been widely used to infer ground and atmospheric properties, and single-station and autocorrelation seismic interferometry has also shown potential for characterizing Earth structure at multiple scales. We extend autocorrelation seismic interferometry to ambient atmospheric infrasound recordings that contain persistent local noise from waterfalls and rivers. Across a range of geographic settings, we retrieve relative sound-speed changes that exhibit clear diurnal oscillations consistent with temperature and wind variations. We estimate ambient air temperatures from variations in relative sound speeds. The frequency band from 1 to 2 Hz appears most suitable to retrieve weather parameters as nearby waterfalls and rivers may act as continuous and vigorous sources of infrasound that help achieve convergence of coherent phases in the autocorrelation codas. This frequency band is also appropriate for local sound-speed variations because it has infrasound with wavelengths of ∼170–340 m, corresponding to a typical atmospheric boundary layer height. After applying array analysis to autocorrelation functions derived from a three-element infrasound array, we find that autocorrelation codas are composed of waves reflected off nearby topographic features, such as caldera walls. Lastly, we demonstrate that autocorrelation infrasound interferometry offers the potential to study the atmosphere over at least several months and with a fine time resolution
Using infrasound waves to monitor tropospheric weather and crater morphology changes at Volcán Tungurahua, Ecuador
No full textWe use infrasound waves generated during eruptions of Volcán Tungurahua (Ecuador) to study both, changing atmospheric conditions and volcanic source characteristics. Analyzed infrasound data were recorded for a 32-month period by a five-station network located within 6.5 km from the vent. We use cross-network correlation to quantify the recurrent eruptive behavior of Tungurahua and results are corroborated by reports from the Ecuadorian monitoring agency. Cross-network lag times vary over short time periods (minutes to days) when vent location is stable and attribute these variations to changes in atmospheric structure. Assuming a fixed source location, we invert for average air temperatures and winds in Tungurahua's vicinity (< 6.5 km) and find evidence for diurnal and semidiurnal tropospheric tides. We also use cross-network correlation lag times to compute infrasound source positions with resolutions of ~ 11.6 m, taking into account coarse NOAA atmospheric models for local winds and temperatures. Variable infrasound-derived source locations suggest source migration during the 32 months of analyzed data. Such source position variability is expected following energetic eruptions that destructively altered the crater/vent morphology as confirmed by imagery obtained during regular overflights
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
Get PDFFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
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