oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 175 )

2018 ( 859 )

2017 ( 787 )

2016 ( 1169 )

Custom range...

Search Results: 1 - 10 of 476865 matches for " James A. Roumasset "
All listed articles are free for downloading (OA Articles)
Page 1 /476865
Display every page Item
Optimal and Sustainable Groundwater Extraction
James A. Roumasset,Christopher A. Wada
Sustainability , 2010, DOI: 10.3390/su2082676
Abstract: With climate change exacerbating over-exploitation, groundwater scarcity looms as an increasingly critical issue worldwide. Minimizing the adverse effects of scarcity requires optimal as well as sustainable patterns of groundwater management. We review the many sustainable paths for groundwater extraction from a coastal aquifer and show how to find the particular sustainable path that is welfare maximizing. In some cases the optimal path converges to the maximum sustainable yield. For sufficiently convex extraction costs, the extraction path converges to an internal steady state above the level of maximum sustainable yield. We describe the challenges facing groundwater managers faced with multiple aquifers, the prospect of using recycled water, and the interdependence with watershed management. The integrated water management thus described results in less water scarcity and higher total welfare gains from groundwater use. The framework also can be applied to climate-change specifications about the frequency, duration, and intensity of precipitation by comparing before and after optimal management. For the case of South Oahu in Hawaii, the prospect of climate change increases the gains of integrated groundwater management.
Elevated Carbon Dioxide Alters the Relative Fitness of Taraxacum officinale Genotypes  [PDF]
James A. Bunce
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.32024
Abstract: I tested whether elevated [CO2] affected which genotypes of Taraxacum officinale had highest fitness in two field experiments. In one experiment, T. officinale plants which persisted as weeds in alfalfa plots in open top chambers at ambient and elevated [CO2] were compared. In a second experiment, T. officinale seeds collected from local habitats were mixed and scattered in open top chambers at ambient and elevated [CO2], and plants producing seeds after one and two years in monocultures were compared. In both experiments seeds produced in each chamber were collected, and many plants from the seed lot from each chamber were grown in controlled environment chambers to test whether the [CO2] of the chamber of origin affected the mean value of various plant parameters. In both experiments, the results indicated that field exposure to elevated [CO2] altered the relative fitness of genotypes. Elevated [CO2] favored genotypes which produced biomass more rapidly at elevated [CO2] in both experiments, primarily because of faster rates of leaf initiation. The results suggest that genotypes of this species vary widely in fitness at elevated [CO2] whether grown in monocultures or in mixed communities, and that this species could adapt rapidly to rising atmospheric [CO2].
Corn Growth Response to Elevated CO2 Varies with the Amount of Nitrogen Applied  [PDF]
James A. Bunce
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.53042
Abstract:

Corn, with C4 photosynthetic metabolism, often has no photosynthetic or yield response to elevated carbon dioxide concentrations. In C3 species, the yield stimulation at elevated carbon dioxide concentrations often decreases with nitrogen limitation. I tested whether such a nitrogen interaction occurred in corn, by growing sweet corn in field plots in open top chambers at ambient and elevated (ambient + 180 mmol·mol-1) carbon dioxide concentrations for four seasons, with six nitrogen application rates, ranging from half to twice the locally recommended rate. At the recommended rate of nitrogen application, no carbon dioxide effect on production occurred. However, both ear and leaf plus stem biomass were lower for the elevated carbon dioxide treatment than for the ambient treatment at less than the recommended rate of nitrogen application, and higher at the highest rates of nitrogen application. There were no significant responses of mid-day leaf gas exchange rates to nitrogen application rate for either carbon dioxide treatment, and elevated carbon dioxide did not significantly increase leaf carbon dioxide assimilation rates at any nitrogen level. Leaf area index during vegetative growth increased more with nitrogen application rate at elevated than at ambient carbon dioxide. It is concluded that elevated carbon dioxide increased the responsiveness of corn growth to nitrogen application by increasing the response of leaf area to nitrogen application rate, and that elevated carbon dioxide increased the amount of nitrogen required to achieve maximum yields.

Managing the Classroom for Creativity  [PDF]
Molly A. James
Creative Education (CE) , 2015, DOI: 10.4236/ce.2015.610102
Abstract: Enhancing student creativity is an educational goal, and increasingly, a global imperative. In the current educational context of the United States, this is a formidable task. I have struggled with this issue as an MA student, and as an educator. As an MA student I examined learning environments that support and enhance creativity, and received my Masters in Creative Thinking. As an educator at an academically rigorous N-12 grade school, I endeavor daily to encourage deep thinking, academic excellence, and great creativity in my students. This paper expresses the voice of the researcher, and the voice of the passionate educator. This paper suggests it is possible to establish creativity-enhancing learning environments. It offers an understanding of creativity and its inherent connection to learning. Teresa Amabile’s highly regarded workplace assessment inventory, KEYS, is presented and explored as a classroom management style that encourages creativity and achievement. Her theory suggests we, as educators, have the power to enhance our students’ creativity by positively impacting our classroom environment. I map her approach onto two highly successful creative learning approaches—El Sistema and Reggio Emilia, and then interrogate and reflect upon the presence of KEYS in my own practice. Finally I offer suggestions for pre-service and in-service professional development to support educators as we work to empower our students to grow their creativity now and in the future.
The Baetylus Theorem—The Central Disconnect Driving Consumer Behavior and Investment Returns in Wearable Technologies  [PDF]
James A. Levine
Technology and Investment (TI) , 2016, DOI: 10.4236/ti.2016.73008
Abstract: The Wearable Technology market may increase fivefold by the end of the decade. There is almost no academic investigation as to what drives the investment hypothesis in wearable technologies. This paper seeks to examine this issue from an evidence-based perspective. There is a fundamental disconnect in how consumers view wearable sensors and how companies market them; this is called The Baetylus Theorem where people believe (falsely) that by buying a wearable sensor they will receive health benefit; data suggest that this is not the case. This idea is grounded social constructs, psychological theories and marketing approaches. A marketing proposal that fails to recognize The Baetylus Theorem and how it can be integrated into a business offering has not optimized its competitive advantage. More importantly, consumers should not falsely believe that purchasing a wearable technology improves health.
Variable Responses to CO2 of the Duration of Vegetative Growth and Yield within a Maturity Group in Soybeans  [PDF]
James A. Bunce
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.713164
Abstract: Prior experiments in indoor chambers and in the field using free-air carbon dioxide enrichment (FACE) systems indicated variation among soybean cultivars in whether and how much elevated CO2 prolonged vegetative development. However, the cultivars tested differed in maturity group, and it is not known whether variation exists in CO2 effects on the duration of vegetative growth within a maturity group. In these experiments, a total of five soybean cultivars of maturity group IV were grown at ambient and elevated CO2 in the field in Maryland, USA using FACE systems, over three years. The time of first flowering, the time of the first open flowers at the apex of the main stem, the total number of main stem nodes at maturity, and seed yield were recorded. In each year of the study, there were cultivars in which elevated CO2 did not affect the duration of vegetative growth or the main stem node number, and other cultivars in which elevated CO2 prolonged vegetative growth and increased the number of main stem nodes and seed yield at maturity. The stimulation in yield by elevated CO2 was highly correlated with the increase in the number of main stem nodes, indicating that CO2 effects on the duration of vegetative growth may be important in adapting soybean to higher atmospheric CO2.
A Five-Step Strategy to Combine Data Sources from Multiple Wearable Sensors  [PDF]
James A. Levine
Technology and Investment (TI) , 2017, DOI: 10.4236/ti.2017.81003
Abstract: With the multitude of non-communicating wearable sensors, there is an urgent need to better combine wearable data streams in order to improve human health and well-being. A five-step process is proposed. The first step is to specify the human behavior that the data set will address. The second step is to critically assess primary measurement that allows the behavioral goal to be addressed. After this, other streams can be integrated in a hierarchical fashion based on their accuracy, precision and relevance. The third step is to perform a hierarchical synthesis of the multiple data streams. In the fourth step, the multiple data streams are integrated for practical use; we propose achieving this with wearable computers. The final step is that system retraining occurs, via Artificial Intelligence, so that an integrated wearable system can be individualized. A case study of Type 1 diabetes is used: this analysis and the proposed solutions illustrate the need for an urgent interdisciplinary debate to advance useful methods for combining data from divergent wearable sensors. Wearable fully integrated systems, programmed with Artificial Intelligence, will enable data from multiple wearable sensors to be optimized to improve individual well-being.
The Application of Wearable Technologies to Improve Healthcare in the World’s Poorest People  [PDF]
James A. Levine
Technology and Investment (TI) , 2017, DOI: 10.4236/ti.2017.82007
Abstract: Wearable technologies could be influential for improving healthcare in underserved areas. Wearable sensors are straightforward to develop, have low production costs and the methods for processing high volumes of data are advanced. Here we examine the application of wearable technology for improving health in three poverty-related scenarios. The first is for diabetes prevention in Mexico City. The second is for medical care in the Kibera slum in Nairobi and the third is for the delivery of “health kits” to refugees. The analysis affirms that investment is worthwhile in mass scalable wearable technologies directed at the half of the world’s population who live in poverty.
A Biologist’s View of Creation  [PDF]
James A. Morris
Open Journal of Philosophy (OJPP) , 2019, DOI: 10.4236/ojpp.2019.91002
Abstract: A model of the Universe is proposed in which three-dimensional space consists of positive and negative charges which are exactly equal and opposite. The charges are separated by a distance d, which is a random variable of the order of 0.1 nm. The charges are produce by continuous creation from nothing and the Universe doubles in volume every 2 to 3 billion years. Vast tracts of space move relative to each other and they meet whirlpools that are produced in which the charges are forced together producing protons and neutrons. Each proton and each neutron consume a pair of charges every 917 seconds and this creates the force of gravity in which space physically contracts around large objects. This concept of gravity is consistent with Newton’s and Einstein’s equations and allows one to visualize curved space and space-time. Focal areas in which the charges are ordered create information and energy. Electromagnetic radiation is a wave of energy in which order forms at the front and dissolves at the rear. Large objects move in a straight line because their electrons order adjacent space and the object moves with a surrounding wave. The quantum world and the world of large objects are not dissimilar and we can construct physical models of the Universe that all intelligent humans can understand. This includes a physical understanding of Schrodinger’s equation and its parameters. Everything in the Universe is composed ultimately of positive and negative charges, which can be combined in an infinite number of ways. This applies to abstract concepts as well as concrete objects. The only difference is that the former is four dimensional and involves complex information flow. Thus human consciousness, behavior, religious beliefs and spiritual experience are just as real and susceptible to scientific study as are anatomy and physiology.
Inexpensive Geophysical Instruments Supporting Groundwater Exploration in Developing Nations  [PDF]
James A. Clark, Richard Page
Journal of Water Resource and Protection (JWARP) , 2011, DOI: 10.4236/jwarp.2011.310087
Abstract: Geophysical methods are often used to aid in exploration for safe and abundant groundwater. In particular resistivity and seismic refraction methods are helpful in determining depth to bedrock and zones of saturation in the subsurface. However the expense of these instruments ($5000 to $20,000) has resulted in their limited use in developing countries. This paper describes how to construct these devices for less than $250 each. The instruments are small, light and robust and are as useful for groundwater exploration as the commercial models for shallow aquifers (less than 35 m deep) where wells can be hand dug, augured or drilled with small portable drill rigs. Data interpretation can be accomplished quickly in the field with free software implemented on a laptop computer. A suite of geophysical instruments and software can therefore be assembled for less than $850. This paper gives the design for these instruments and essential information needed to use them. It is hoped that these inexpensive geophysical instruments can be widely distributed among drillers and aid workers in developing countries, improving the success rate of water wells.
Page 1 /476865
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.