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Articles 1 - 30 of 35
Full-Text Articles in Physical Sciences and Mathematics
Minerva 2009, The Honors College
Minerva 2009, The Honors College
Minerva
This issue of Minerva includes a story on alumna Betsy Leitch and her husband Bill Leitch, Betsy's connection to Colvin Hall, and their ongoing support of Honors; an article about Colvin Hall renovations and the opening of the Margaret Chase Smith Visiting Faculty Suite; and an interview with Pulitzer Prize-winning Honors graduate, Bettina Boxall. Other highlights include the story of Honors graduate Adam Jones and his involvement in saving the USS Alabama.
Remarks On The Stability Of Some Size-Structured Population Models V: The Case When The Death Rate Depends On Adults Only And The Growth Rate Depends On Size Only, M. El-Doma
Applications and Applied Mathematics: An International Journal (AAM)
We continue our study of size-structured population dynamics models when the population is divided into adults and juveniles, started in El-Doma (To appear). We concentrate our efforts in the special case when the death rate depends on adults only, the growth rate depends on size only and the maximum size for an individual in the population is infinite. Three demographic parameters are identified and are shown to determine conditions for the (in)stability of a nontrivial steady state. We also give examples that illustrate the stability results. The results in this paper generalize previous results, for example, see Calsina, et al. …
Two-Layered Model Of Blood Flow Through Composite Stenosed Artery, Padma Joshi, Ashutosh Pathak, B. K. Joshi
Two-Layered Model Of Blood Flow Through Composite Stenosed Artery, Padma Joshi, Ashutosh Pathak, B. K. Joshi
Applications and Applied Mathematics: An International Journal (AAM)
In this paper a steady, axisymmetric flow, with a constricted tube has been studied. The artery has been represented by a two-layered model consisting of a core layer and a peripheral layer. It has been shown that the resistance to flow and wall shear stress increases as the peripheral layer viscosity increases. The results are compared graphically with those of previous investigators. It has been observed that the existence of peripheral layer is useful in representation of diseased arterial system.
Remarks On The Stability Of Some Size-Structured Population Models Vi: The Case When The Death Rate Depends On Juveniles Only And The Growth Rate Depends On Size Only And The Case When Both Rates Depend On Size Only, M. El-Doma
Applications and Applied Mathematics: An International Journal (AAM)
We continue our study of size-structured population dynamics models when the population is divided into adults and juveniles, started in El-Doma (to appear 1) and continued in El-Doma (to appear 2). We concentrate our efforts in two special cases, the first is when the death rate depends on juveniles only and the growth rate depends on size only, and, the second is when both the death rate and the growth rate depend on size only. In both special cases we assume that the maximum size for an individual in the population is infinite. We identify three demographic parameters and show …
Remarks On The Stability Of Some Size-Structured Population Models Iv: The General Case Of Juveniles And Adults, M. El-Doma
Applications and Applied Mathematics: An International Journal (AAM)
The stability of some size-structured population dynamics models is investigated when the population is divided into adults and juveniles. We determine the steady states and study their stability. We also give examples that illustrate the stability results. The results in this paper generalize previous results, for example, see Calsina, et al. (2003), El-Doma (2006), Farkas, et al. (2008), and El-Doma (2008 a).
Pulsatile Flow Of Blood In A Constricted Artery With Body Acceleration, Devajyoti Biswas, Uday Shankar Chakraborty
Pulsatile Flow Of Blood In A Constricted Artery With Body Acceleration, Devajyoti Biswas, Uday Shankar Chakraborty
Applications and Applied Mathematics: An International Journal (AAM)
Pulsatile flow of blood through a uniform artery in the presence of a mild stenosis has been investigated in this paper. Blood has been represented by a Newtonian fluid. This model has been used to study the influence of body acceleration and a velocity slip at wall, in blood flow through stenosed arteries. By employing a perturbation analysis, analytic expressions for the velocity profile, flow rate, wall shear stress and effective viscosity, are derived. The variations of flow variables with different parameters are shown diagrammatically and discussed. It is noticed that velocity and flow rate increase but effective viscosity decreases, …
Phytoplankton Blooms: Their Occurrence And Composition Within Virginia's Tidal Tributaries, Harold G. Marshall, Todd A. Egerton
Phytoplankton Blooms: Their Occurrence And Composition Within Virginia's Tidal Tributaries, Harold G. Marshall, Todd A. Egerton
Virginia Journal of Science
Sporadic algal bloom development within a 10 year monitoring program in Virginia tidal tributaries of Chesapeake Bay is reviewed. These blooms were common events, characteristically producing a color signature to the surface water, typically short lived, occurring mainly from spring into autumn throughout different salinity regions of these rivers, and were produced primarily by dinoflagellates. The abundance threshold levels that would identify bloom status from a non-bloom presence were species specific, varied with the taxon's cell size, and ranged from ca. 10 to 104 cells mL-1. Among the most consistent sporadic bloom producers were the dinoflagellates Akashiwo …
First Records Of Hypleurochilus Geminatus And Centropristis Philadelphica From Chesapeake Bay, Aimee D. Halvorson
First Records Of Hypleurochilus Geminatus And Centropristis Philadelphica From Chesapeake Bay, Aimee D. Halvorson
Virginia Journal of Science
During the fall of 2007, Centropris philadelphica (rock seabass) and Hypleurochilus geminatus (Crested blenny) were collected from Chesapeake Bay. These captures are significant as they represent the first substantiated record of C. philadelphica from Chesapeake Bay and only the second and third validated records of H. geminatus. Additionally, the first record of H. geminatus from Chesapeake Bay was only recently recognized since the specimen had been previously misidentified as Parablennius marmoreus (seaweed blenny). The collection of seven individuals of H. geminatus in 2007, from two locations, indicates that the species may be resident within the Chesapeake Bay estuary.
Effects Of Hematocrit On Impedance And Shear Stress During Stenosed Artery Catheterization, V. P. Srivastava, Rati Rastogi
Effects Of Hematocrit On Impedance And Shear Stress During Stenosed Artery Catheterization, V. P. Srivastava, Rati Rastogi
Applications and Applied Mathematics: An International Journal (AAM)
The flow of blood through a stenosed catheterized artery has been studied. To observe the effects of hematocrit, blood has been represented by a two-phase macroscopic model (i.e., a suspension of red cells in plasma). It is found that for any given catheter size, the impedance increases with hematocrit and also for a given hematocrit, the same increases with the catheter size. In the stenotic region, the wall shear stress increases in the upstream of the stenosis throat and decreases in the downstream in an uncatheterized artery but the same possesses an opposite character in the case of a catheterized …
Stability Of An Age-Structured Seir Epidemic Model With Infectivity In Latent Period, Xue-Zhi Li, Bin Fang
Stability Of An Age-Structured Seir Epidemic Model With Infectivity In Latent Period, Xue-Zhi Li, Bin Fang
Applications and Applied Mathematics: An International Journal (AAM)
We study an age-structured SEIR epidemic model with infectivity in the latent period. By using the theory and methods of Differential and Integral Equations, the explicit expression for the basic reproductive number R0 is first derived. It is shown that the disease-free equilibrium is locally and globally asymptotically stable if R0 < 1. It is then proved that only one endemic equilibrium exists if R0 > 1 and its stability conditions are also given.
Effect Of Glycocalyx On Red Blood Cell Motion In Capillary Surrounded By Tissue, Rekha Bali, Swati Mishra, P. N. Tandon
Effect Of Glycocalyx On Red Blood Cell Motion In Capillary Surrounded By Tissue, Rekha Bali, Swati Mishra, P. N. Tandon
Applications and Applied Mathematics: An International Journal (AAM)
The aim of the paper is to develop a simple model for capillary tissue fluid exchange system to study the effect of glycocalyx layer on the single file flow of red cells. We have considered the channel version of an idealized Krogh capillary-tissue exchange system. The glycocalyx and the tissue are represented as porous layers with different property parametric values. Hydrodynamic Lubrication theory is used to compute the squeezing flow of plasma within the small gap between the cell and the glycocalyx layer symmetrically surrounded by the tissue. The system of non linear partial differential equations has been solved using …
Modeling And Analysis Of The Spread Of Japanese Encephalitis With Environmental Effects, Ram Naresh, Surabhi Pandey
Modeling And Analysis Of The Spread Of Japanese Encephalitis With Environmental Effects, Ram Naresh, Surabhi Pandey
Applications and Applied Mathematics: An International Journal (AAM)
A nonlinear mathematical model for the spread of Japanese Encephalitis, caused by infected mosquito feeding on susceptible human population incorporating demographic and environmental factors is proposed and analyzed. In the modeling process, it is assumed that the growth rates of reservoir animal population and vector mosquito population are enhanced due to environmental discharges caused by human population related factors. The model is analyzed by stability theory of differential equations and computer simulation. Both the disease-free and the endemic equilibria are found and their stability is investigated. It is found that whenever the disease-free equilibrium is locally asymptotically stable, the endemic …
Management And Social Indicators Of Soil Carbon Storage In A Residential Ecosystem, Midlothian, Va, Christopher M. Gough, Eliza A. Fritz
Management And Social Indicators Of Soil Carbon Storage In A Residential Ecosystem, Midlothian, Va, Christopher M. Gough, Eliza A. Fritz
Virginia Journal of Science
Soil carbon storage- defined here as carbon mass per unit ground area- is an important ecosystem service, sequestering carbon that might otherwise exist in atmospheric CO2 . Significant attention has focused on the effects that humans have on carbon cycling, but little is known about how human behaviors and attitudes relate to lawn carbon storage. The objectives of this study were to conduct household surveys in concert with soil carbon sampling in a 10-year-old exurban neighborhood near Richmond, Virginia to quantify differences in soil carbon storage between residential lawns and mixed pine-hardwood forest fragments, and to determine how lawn …
Downregulation Of Hiv-1 Vif By A Hammerhead Ribozyme Expressed From A Retroviral Vector, Audrey M. Hendley, William Jackson
Downregulation Of Hiv-1 Vif By A Hammerhead Ribozyme Expressed From A Retroviral Vector, Audrey M. Hendley, William Jackson
Journal of the South Carolina Academy of Science
No abstract provided.
Synthesis Of Fatty Acid Binding Protein Inhibitors: A New Approach For Diabetes Treatment, Shekelia Baccus, M. Perry Davis Jr, David R. Magnin
Synthesis Of Fatty Acid Binding Protein Inhibitors: A New Approach For Diabetes Treatment, Shekelia Baccus, M. Perry Davis Jr, David R. Magnin
Journal of the South Carolina Academy of Science
No abstract provided.
Effect Of Thaw Temperature On Murine Blastocyst Development, Heather M. Barton, H. Lee Higdon Iii, Ph.D., Jennifer E. Graves-Herring M.S., William R. Boone, Ph.D.
Effect Of Thaw Temperature On Murine Blastocyst Development, Heather M. Barton, H. Lee Higdon Iii, Ph.D., Jennifer E. Graves-Herring M.S., William R. Boone, Ph.D.
Journal of the South Carolina Academy of Science
No abstract provided.
Generation Of A Retroviral Vector That Expresses An Anti-Hiv-1 Tat Hammerhead Ribozyme, Lindsey E. Padgett, William H. Jackson
Generation Of A Retroviral Vector That Expresses An Anti-Hiv-1 Tat Hammerhead Ribozyme, Lindsey E. Padgett, William H. Jackson
Journal of the South Carolina Academy of Science
No abstract provided.
Where Do Mouse Embryos Thrive Best? Comparison Of Mammalian Embryo Development Under Varying Laboratory Environments, Yvonne K. Kao, H. Lee Higdon Iii, Ph.D, Jennifer E. Graves-Herring , M.S., William R. Boone Ph.D
Where Do Mouse Embryos Thrive Best? Comparison Of Mammalian Embryo Development Under Varying Laboratory Environments, Yvonne K. Kao, H. Lee Higdon Iii, Ph.D, Jennifer E. Graves-Herring , M.S., William R. Boone Ph.D
Journal of the South Carolina Academy of Science
No abstract provided.
Temperature Changes Resulting From A Gaalas Laser In The Decontamination Of A Failing Dental Implant, Adam B. Oppenheimer
Temperature Changes Resulting From A Gaalas Laser In The Decontamination Of A Failing Dental Implant, Adam B. Oppenheimer
Journal of the South Carolina Academy of Science
No abstract provided.
Biological And Economic Considerations In Establishing A Short-Rotation Bioenergy Plantation, Jamie L. Schuler, M. Pelkki, Chris Stuhlinger
Biological And Economic Considerations In Establishing A Short-Rotation Bioenergy Plantation, Jamie L. Schuler, M. Pelkki, Chris Stuhlinger
Journal of the Arkansas Academy of Science
The development of bio-fuel synthesis technologies has led to increased interest in woody crops grown specifically for energy production. These woody feedstocks typically involve fast-growing species (e.g., Salix spp., Populus spp.) planted at high densities using short rotations and intensive cultural practices like weed control and fertilization. Under ideal conditions, this type of system can produce 20 dry Mg/ha/yr, which is substantially higher than the 2.5-4 dry Mg/ha/yr produced by pine plantations in the southern U.S. Many of these plantings are projected to be established on lower quality agricultural lands. Recent attempts at establishing these plantations have highlighted some of …
Enhancing Iowa High School Students' Transition To College, K. E. Lassila, L. C. Rule, C. Lee, R. J. Driggs, G. Fulton, M. Skarda, J. Torres Y Torres
Enhancing Iowa High School Students' Transition To College, K. E. Lassila, L. C. Rule, C. Lee, R. J. Driggs, G. Fulton, M. Skarda, J. Torres Y Torres
Journal of the Iowa Academy of Science: JIAS
We present our studies of the transitions of Iowa science students from high school to post-secondary colleges. Our report summarizes information and impressions from dealing with thousands of new students arriving at our six colleges, along with meetings and discussions with high school science teachers to add their viewpoints into our considerations. Feedback from community college, four year college, and high school science teachers highlighted the following five study issues and needs for improving student transitions from high school to college science: 1) Better math preparation is needed; 2) More work with inquiry-based learning rather than with facts and memorization …
The Freshwater Mussels (Mollusca: Bivalvia: Unionidae) Of The Channelized Missouri River, Ellet Hoke
The Freshwater Mussels (Mollusca: Bivalvia: Unionidae) Of The Channelized Missouri River, Ellet Hoke
Journal of the Iowa Academy of Science: JIAS
The lower Missouri River has historically been viewed as a fauna! barrier for unionids due to high sediment load. However this survey of the lower (channelized) Missouri River documented the presence of 14 unionid species and the exotic Corbicula fluminea (Muller, 1774). Unionids are present in stable substrates sheltered from the effects of the river's strong currents. Analysis of early literature on the Missouri River suggests reports of an absence of unionids were not based upon thorough fieldwork, and the most commonly cited rationale for their reported absence, the high sediment load in the river, is not convincing. Pre-1938 unionid …
Table Of Contents (Back Cover)
Table Of Contents (Back Cover)
Journal of the Iowa Academy of Science: JIAS
No abstract provided.
Gully And Stream Bank Erosion In Three Pastures With Different Management In Southeast Iowa, George N. Zaimes, Richard C. Schultz, Mustafa Tufekcioglu
Gully And Stream Bank Erosion In Three Pastures With Different Management In Southeast Iowa, George N. Zaimes, Richard C. Schultz, Mustafa Tufekcioglu
Journal of the Iowa Academy of Science: JIAS
Gully and stream banks can be major sources of sediment and nutrients to surface waters, both major water quality problems in the United States. Sediment may also carry phosphorus to surface waters, the primary limiting nutrient causing eutrophication. Overgrazing can induce gully and stream bank erosion by reducing vegetation cover that weakens bank soil resistance to stream water flow. This study examines stream and gully bank erosion adjacent to continuous (CP), rotational (RP) and intensive rotational (IP) pastures, grazed by beef cattle in southeast Iowa. Stream and gully bank erosion were measured by: a) surveying the extent of the severely …
Dr. Lois Hattery Tiffany (1924-2009): In Memoriam, Deborah Q. Lewis
Dr. Lois Hattery Tiffany (1924-2009): In Memoriam, Deborah Q. Lewis
Journal of the Iowa Academy of Science: JIAS
Dr. Lois Hartery Tiffany, Distinguished Professor Emerita, Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa, died on 6 September 2009. Dr. Tiffany was an outstanding mycologist and teacher. Held in high regard by the public as "Iowa's Mushroom Lady" and known by many students, colleagues and friends as "Dr. T.," she was the matriarch of the Botany Department (now the Department of Ecology, Evolution and Organismal Biology) at Iowa State.
Editorial Board & Iowa Academy Of Science Officers And Directors
Editorial Board & Iowa Academy Of Science Officers And Directors
Journal of the Iowa Academy of Science: JIAS
No abstract provided.
Som Loss And Soil Quality In The Clear Creek, Ia, A. N. Thanos Papanicolaou, Christopher G. Wilson, Ozan Abaci, Mohamed Elhakeem, Mary Skopec
Som Loss And Soil Quality In The Clear Creek, Ia, A. N. Thanos Papanicolaou, Christopher G. Wilson, Ozan Abaci, Mohamed Elhakeem, Mary Skopec
Journal of the Iowa Academy of Science: JIAS
The Clear Creek, IA Experimental Watershed (CCEW), which drains to the Iowa River, experiences severe surface erosion due to a combination of high slopes, erodible soils, and extensive agriculture. Concurrent with soil loss is the removal of Soil Organic Matter (SOM). High values of SOM have been related to soil quality; therefore, excessive SOM loss corresponds to degrading soil health. Soil quality assessments are important tools for evaluating management practices in agricultural systems; however, it is difficult to measure soil quality directly at the watershed scale because it varies with a number of site-specific soil characteristics. The coupling of soil …
Aryl Ethers From Arenediazonium Tetrafluoroborate Salts: From Neat Reactions To Solvent-Mediated Effects, James A. Shriver, Daniel P. Flaherty, Cameron C. Herr
Aryl Ethers From Arenediazonium Tetrafluoroborate Salts: From Neat Reactions To Solvent-Mediated Effects, James A. Shriver, Daniel P. Flaherty, Cameron C. Herr
Journal of the Iowa Academy of Science: JIAS
A general procedure for the synthesis of various aryl ethers via the thermal decomposition of benzenediazonium tetrafluoroborate salts is described. Studies performed in neat alcohol at 60°C gave aryl ethers in yields ranging from 0-73%. Upon completion of a series of reactions, the effect of solvent was explored to expand the scope and relevance of this procedure. It was found that even solvents that are traditionally non-nucleophilic gave rise to products including bi-aryls and N-aryl acetamides. The utilization of an ionic liquid, l-butyl-4-methylpyridinium tetrafluoroborate, resulted in yields comparable to reactions performed in neat alcoholic solvents.