Growth and Reproductive Physiology of Fluridone-Susceptible and -resistant Hydrilla (Hydrilla verticillata) Biotypes

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 441-445 ◽  
Author(s):  
Atul Puri ◽  
Gregory E. MacDonald ◽  
William T. Haller ◽  
Megh Singh
Keyword(s):  
United States ◽  
Hydrilla Verticillata ◽  
The United States ◽  
Reproductive Physiology ◽  
Day Length ◽  
Aquatic Weed ◽  
Environment Protection ◽  
Economic Problems ◽  
Systemic Control

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. Several biotypes of hydrilla varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions from September 2004 to September 2005 in absence of fluridone. Phenotypic measurements were performed during this 1-yr period to monitor differences in growth and reproductive physiology. All fluridone-resistant biotypes (except R3) were growing at the same rate or greater than the susceptible hydrilla. These data suggested that there are no deleterious effects on growth and reproductive physiology because of development of fluridone resistance. Aggressive spread of fluridone-resistant dioecious hydrilla in aquatic ecosystems can severely affect hydrilla management and, consequently, cause substantial and long-lasting ecological and economic problems throughout the southern United States.

Mutations in Phytoene Desaturase Gene in Fluridone-Resistant Hydrilla (Hydrilla verticillata) Biotypes in Florida

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 412-420 ◽  
Author(s):  
Atul Puri ◽  
Gregory E. MacDonald ◽  
Fredy Altpeter ◽  
William T. Haller
Keyword(s):  
Herbicide Resistance ◽  
Single Point ◽  
Hydrilla Verticillata ◽  
The United States ◽  
Phytoene Desaturase ◽  
Day Length ◽  
Single Point Mutation ◽  
Aquatic Weed ◽  
Systemic Control

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. One susceptible and five fluridone-resistant biotypes of hydrilla varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions from September 2004 to September 2005 in absence of fluridone. Because fluridone is an inhibitor of the enzyme phytoene desaturase (PDS), the gene for PDS (pds) was cloned from fluridone-susceptible and -resistant hydrilla biotypes. Somatic mutations in amino acid 304 of hydrilla PDS are known to confer herbicide resistance. We determinedpdssequence from these hydrilla biotypes at planting and 12-mo after planting. Two independent mutations at the arginine 304 codon ofpdswere found in the resistant hydrilla plants. The codon usage for arginine 304 is CGT, and a single point mutation yielding either serine (AGT) or histidine (CAT) was identified in different resistant hydrilla biotypes. There were no differences at codon 304 in the PDS protein of any hydrilla biotype 12-mo after planting. Several other mutations were also found in resistantpdsalleles, though their possible role in herbicide resistance is unclear.

Ploidy Variations in Floridone-Susceptible and -Resistant Hydrilla (Hydrilla verticillata) Biotypes

Weed Science ◽  
2007 ◽  
Vol 55 (6) ◽  
pp. 578-583 ◽  
Author(s):  
Atul Puri ◽  
Gregory E. MacDonald ◽  
William T. Haller
Keyword(s):  
Nuclear Dna ◽  
Flow Cytometric Analysis ◽  
Nuclear Dna Content ◽  
Hydrilla Verticillata ◽  
The United States ◽  
Day Length ◽  
Aquatic Weed ◽  
Ploidy Levels ◽  
Systemic Control ◽  
Dna Contents

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. Fluridone-susceptible (S) and several fluridone-resistant (R1 to R5) hydrilla biotypes varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions. To correlate varying levels of fluridone resistance to ploidy in hydrilla, flow cytometric analysis was performed. Differential ploidy levels (diploid, 2n = 2x = 16; triploid, 2n = 3x = 24; and tetraploid, 2n = 4x = 32) were reported among different hydrilla biotypes, plants within each biotype, and within shoot tissues of the same plant. Triploid plants were predominant in all biotypes. Diploid plants were observed in all hydrilla biotypes except the susceptible hydrilla (S). Plants with tetraploidy were rare within biotypes. The diploid, triploid, and tetraploid plants had nuclear DNA contents of 2.43 to 2.73 pg, 3.44 to 3.71 pg, and 4.64 to 4.90 pg, respectively, and no differences were observed among plants with same ploidy for nuclear DNA content in different hydrilla biotypes. Endoreduplication patterns were observed in diploid plants of R1 and R3 biotypes. However, no plant with higher ploidy levels (triploid or tetraploid) in any hydrilla biotypes showed endoreduplication.

Stability of Fluridone-Resistant Hydrilla (Hydrilla verticillata) Biotypes over Time

Weed Science ◽  
2007 ◽  
Vol 55 (1) ◽  
pp. 12-15 ◽  
Author(s):  
Atul Puri ◽  
G. E. MacDonald ◽  
W. T. Haller
Keyword(s):  
Hydrilla Verticillata ◽  
The United States ◽  
Time Interval ◽  
Aquatic Weed ◽  
Atmospheric Conditions ◽  
Carotene Content ◽  
Systemic Control ◽  
Β Carotene ◽  
Over Time

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only herbicide approved by the U.S. Environment Protection Agency that provides systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. Hydrilla biotypes of varying fluridone resistance levels were maintained in 900-L tanks under natural atmospheric conditions from September 2004 to September 2005 in the absence of fluridone. Hydrilla shoot tips were collected from each biotype during September 2004 (at planting), December 2004 (3 mo after planting [MAP]), March 2005 (6 MAP), June 2005 (9 MAP), and September 2005 (12 MAP) and exposed to 5, 10, 15, 20, 30, and 50 µg L−1fluridone to assess changes in susceptibility to this herbicide over time. Nonlinear regression analysis was used to calculate EC50values for phytoene and β-carotene (effective fluridone concentration to increase/decrease the phytoene/β-carotene content in hydrilla plant tissue by 50% over the untreated control) at each time interval. EC50values did not change in the susceptible hydrilla biotype over time. The EC50values for phytoene and β-carotene for the susceptible biotype were 7.5 and 8.9 µg L−1, respectively, at planting and 7.6 and 9.4 µg L−1, respectively, at 12 MAP. Resistant hydrilla biotypes (R1–R5) also showed no change in EC50phytoene values over time. Although, EC50β-carotene values in resistant biotypes R1, R3, R4, and R5 did not change over time, R2 recorded a reduction in EC50β-carotene at 12 MAP. Also, a 0.5-point decrease in resistance factor was observed for all resistant biotypes. Future long-term studies are needed to evaluate stability of resistant hydrilla biotypes in the absence of fluridone selection pressure.

Speech-Language Pathology in the Peace Corps: Necessity and Sustainability

2012 ◽  
Vol 2 (1) ◽  
pp. 11-18
Author(s):  
Melissa A. Pierce
Keyword(s):  
United States ◽  
Special Education ◽  
Peace Corps ◽  
People With Disabilities ◽  
Communication Disorders ◽  
The United States ◽  
Speech Language Pathology ◽  
Speech Language Pathologists ◽  
Language Pathology

In countries other than the United States, the study and practice of speech-language pathology is little known or nonexistent. Recognition of professionals in the field is minimal. Speech-language pathologists in countries where speech-language pathology is a widely recognized and respected profession often seek to share their expertise in places where little support is available for individuals with communication disorders. The Peace Corps offers a unique, long-term volunteer opportunity to people with a variety of backgrounds, including speech-language pathologists. Though Peace Corps programs do not specifically focus on speech-language pathology, many are easily adapted to the profession because they support populations of people with disabilities. This article describes how the needs of local children with communication disorders are readily addressed by a Special Education Peace Corps volunteer.

Mafias on the Move

2011 ◽  
Author(s):  
Federico Varese
Keyword(s):  
United States ◽  
New York ◽  
Organized Crime ◽  
The United States ◽  
The West ◽  
Market Expansion ◽  
The North ◽  
Economic Transformations ◽  
At Will

Organized crime is spreading like a global virus as mobs take advantage of open borders to establish local franchises at will. That at least is the fear, inspired by stories of Russian mobsters in New York, Chinese triads in London, and Italian mafias throughout the West. As this book explains, the truth is more complicated. The author has spent years researching mafia groups in Italy, Russia, the United States, and China, and argues that mafiosi often find themselves abroad against their will, rather than through a strategic plan to colonize new territories. Once there, they do not always succeed in establishing themselves. The book spells out the conditions that lead to their long-term success, namely sudden market expansion that is neither exploited by local rivals nor blocked by authorities. Ultimately the inability of the state to govern economic transformations gives mafias their opportunity. In a series of matched comparisons, the book charts the attempts of the Calabrese 'Ndrangheta to move to the north of Italy, and shows how the Sicilian mafia expanded to early twentieth-century New York, but failed around the same time to find a niche in Argentina. The book explains why the Russian mafia failed to penetrate Rome but succeeded in Hungary. A pioneering chapter on China examines the challenges that triads from Taiwan and Hong Kong find in branching out to the mainland. This book is both a compelling read and a sober assessment of the risks posed by globalization and immigration for the spread of mafias.

Leaded Aviation Fuel May Present Long-Term Effects on Campus Life from the Adjacent Albert Whitted Airport

2020 ◽  
Author(s):  
Joseph Matthews ◽  
Madhu Pandey
Keyword(s):  
United States ◽  
Particulate Matter ◽  
The United States ◽  
Aviation Fuel ◽  
University Campus ◽  
Long Term Effects ◽  
Aviation Gasoline ◽  
Suspended Particulate ◽  
Descent Line

Propeller planes and small engine aircraft around the United States, legally utilize leaded aviation gasoline. The purpose of this experiment was to collect suspended particulate matter from a university campus, directly below an airport’s arriving flight path’s descent line, and to analyze lead content suspended in the air. Two collection sets of three separate samples were collected on six separate days, one set in July of 2018 and the second set in January 2019.

Markets, Technological Change and Economic Growth (The Quaid-i-Azam Lecture)

1994 ◽  
Vol 33 (4I) ◽  
pp. 327-356 ◽  
Author(s):  
Richard G. Lipsey
Keyword(s):  
United States ◽  
Economic Growth ◽  
Developing Countries ◽  
Common Ground ◽  
The United States ◽  
Industrial Countries ◽  
Canadian Institute ◽  
Primary Focus ◽  
Short Time

I am honoured to be invited to give this lecture before so distinguished an audience of development economists. For the last 21/2 years I have been director of a project financed by the Canadian Institute for Advanced Research and composed of a group of scholars from Canada, the United States, and Israel.I Our brief is to study the determinants of long term economic growth. Although our primary focus is on advanced industrial countries such as my own, some of us have come to the conclusion that there is more common ground between developed and developing countries than we might have first thought. I am, however, no expert on development economics so I must let you decide how much of what I say is applicable to economies such as your own. Today, I will discuss some of the grand themes that have arisen in my studies with our group. In the short time available, I can only allude to how these themes are rooted in our more detailed studies. In doing this, I must hasten to add that I speak for myself alone; our group has no corporate view other than the sum of our individual, and very individualistic, views.

The Future of Muslim Education in the United States: An Agenda for Research

2003 ◽  
Vol 20 (3-4) ◽  
pp. 46-82
Author(s):  
Fathi Malkawi
Keyword(s):  
United States ◽  
The United States ◽  
American Education ◽  
Future Trends ◽  
Muslim Community ◽  
Short Term ◽  
The Future ◽  
Muslim Education ◽  
Future Plans

This paper addresses some of the Muslim community’s concerns regarding its children’s education and reflects upon how education has shaped the position of other communities in American history. It argues that the future of Muslim education will be influenced directly by the present realities and future trends within American education in general, and, more importantly, by the well-calculated and informed short-term and long-term decisions and future plans taken by the Muslim community. The paper identifies some areas in which a wellestablished knowledge base is critical to making decisions, and calls for serious research to be undertaken to furnish this base.

Liberating Afghan Women

2004 ◽  
Vol 21 (3) ◽  
pp. 70-88 ◽  
Author(s):  
Nancy Gallagher
Keyword(s):  
United States ◽  
Human Rights ◽  
Historical Context ◽  
The United States ◽  
Political Organizations ◽  
Way Of Life ◽  
Afghan Women ◽  
The Media ◽  
Policy Priority

Public opinion in the United States and elsewhere celebrated the liberation of Afghan women following the defeat of the Taliban government. The United States promised to stay in Afghanistan and foster security, economic development, and human rights for all, especially women. After years of funding various anti- Soviet Mujahidin warlords, the United States had agreed to help reconstruct the country once before in 1992, when the Soviet-backed government fell, but had lost interest when the warlords began to fight among themselves. This time, however, it was going to be different. To date, however, conditions have not improved for most Afghan women and reconstruction has barely begun. How did this happen? This article explores media presentations of Afghan women and then compares them with recent reports from human rights organizations and other eyewitness accounts. It argues that the media depictions were built on earlier conceptions of Muslim societies and allowed us to adopt a romantic view that disguised or covered up the more complex historical context of Afghan history and American involvement in it. We allowed ourselves to believe that Afghans were exotic characters who were modernizing or progressing toward a western way of life, despite the temporary setback imposed by the Taliban government. In Afghanistan, however, there was a new trope: the feminist Afghan woman activist. Images of prominent Afghan women sans burqa were much favored by the mass media and American policymakers. The result, however, was not a new focus on funding feminist political organizations or making women’s rights a foreign policy priority; rather, it was an unwillingness to fulfill obligations incurred during decades of American-funded mujahidin warfare, to face the existence of deteriorating conditions for women, resumed opium cultivation, and a resurgent Taliban, or to commit to a multilateral approach that would bring in the funds and expertise needed to sustain a long-term process of reconstruction.

Asian Americans and Pacific Islanders: Employment Issues in the United States

2011 ◽  
Vol 9 (1-2) ◽  
pp. 58-69
Author(s):  
Marlene Kim
Keyword(s):  
United States ◽  
Asian Americans ◽  
The United States ◽  
Current Data ◽  
Pacific Islanders ◽  
Native Hawaiians ◽  
Data Sets ◽  
High Poverty ◽  
Unemployment Rates

Asian Americans and Pacific Islanders (AAPIs) in the United States face problems of discrimination, the glass ceiling, and very high long-term unemployment rates. As a diverse population, although some Asian Americans are more successful than average, others, like those from Southeast Asia and Native Hawaiians and Pacific Islanders (NHPIs), work in low-paying jobs and suffer from high poverty rates, high unemployment rates, and low earnings. Collecting more detailed and additional data from employers, oversampling AAPIs in current data sets, making administrative data available to researchers, providing more resources for research on AAPIs, and enforcing nondiscrimination laws and affirmative action mandates would assist this population.

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