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2012

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Articles 6211 - 6240 of 6458

Full-Text Articles in Life Sciences

Load-Carrying Capacity Of Mitered Furniture Corner Joints With Dovetail Keys Under Diagonal Tension Load, Sadegh Maleki, Mohammad Derikvand, Mosayeb Dalvand, Ghanbar Ebrahimi Jan 2012

Load-Carrying Capacity Of Mitered Furniture Corner Joints With Dovetail Keys Under Diagonal Tension Load, Sadegh Maleki, Mohammad Derikvand, Mosayeb Dalvand, Ghanbar Ebrahimi

Turkish Journal of Agriculture and Forestry

The goal of this study was to introduce a method for estimating stress analysis as an efficient procedure for evaluating the strength of mitered corner joints in furniture structures. Tests were carried out to determine the effects of panel type, distance between the centers of dovetail holes and the edges of joints (10, 20, and 30 mm), and type of dovetail key on the load-carrying capacity of mitered corner joints under a diagonal tension load. Specimens were constructed of overlaid medium-density fiberboard (LamMDF) and particleboard (LamPb) and connected with butterfly and H-shaped dovetail keys. Polyvinyl acetate adhesive was used to …


Foliar Application Of Calcium Chloride And Borax Influences Plant Growth, Yield, And Quality Of Tomato (Lycopersicon Esculentum Mill.) Fruit, Abdur Rab, Ihsan-Ul Haq Jan 2012

Foliar Application Of Calcium Chloride And Borax Influences Plant Growth, Yield, And Quality Of Tomato (Lycopersicon Esculentum Mill.) Fruit, Abdur Rab, Ihsan-Ul Haq

Turkish Journal of Agriculture and Forestry

The influence of CaCl_2 and borax on growth, yield, and quality of tomato was investigated during the years 2009 and 2010. The experiment was laid out with a randomized complete block design. Calcium chloride (0.3% and 0.6%) and borax (0.2% and 0.4%) solutions were applied as foliar sprays either alone or in combination and data were recorded for plant height, branches per plant, flowers per cluster, fruits per plant, yield, fruit weight, fruit firmness, and total soluble solid content of the fruit. The application of CaCl_2 alone significantly increased the plant height and fruits per plant and decreased the incidence …


Effect Of Al Compounds On Soil Ph And Bioavailability Of Al In Two Acid Soils, Toufiq Iqbal Jan 2012

Effect Of Al Compounds On Soil Ph And Bioavailability Of Al In Two Acid Soils, Toufiq Iqbal

Turkish Journal of Agriculture and Forestry

Two aluminum compounds, AlCl_3 and Al(OH)_3, were used to determine the effect of Al compounds on pH and bioavailability of Al in 2 acid soils. Both soils were incubated for periods of 3, 10, and 30 days. Al-tolerant (ET8) and Al-sensitive (ES8) wheat seedlings were used as a testing plant to confirm bioavailability of Al^{3+} in soil solution. Both soils were acidified through the addition of Al compounds to detect the maximum Al^{3+} toxicity level of these compounds. The results showed that the AlCl3 compound increased the bioavailability of Al^{3+} in soil solutions. In contrast, AlCl_3 decreased bulk soil pH. …


Some Quality Characteristics Of Selected Durum Wheat (Triticum Durum) Landraces, Abdulvahi̇t Sayaslan, Mehmet Koyuncu, Ahmet Yildirim, Tuğba Güleç, Özlem Ateş Sönmezoğlu, Nejdet Kandemi̇r Jan 2012

Some Quality Characteristics Of Selected Durum Wheat (Triticum Durum) Landraces, Abdulvahi̇t Sayaslan, Mehmet Koyuncu, Ahmet Yildirim, Tuğba Güleç, Özlem Ateş Sönmezoğlu, Nejdet Kandemi̇r

Turkish Journal of Agriculture and Forestry

Durum wheat (Triticum durum) is primarily used for the production of high-quality pasta products because of its certain superior characteristics. Wheat landraces are locally adapted diverse populations evolved through natural selection and are invaluable genetic resources for breeding programs. The search for new genetic resources all around the world has been underway to develop high-quality durum wheats. The purpose of this study was therefore to determine the pasta quality-associated characteristics of 12 durum wheat landraces (Bağacak, Beyaziye, İskenderiye, Sorgül, Karakılçık, Beyaz Buğday, Ağ Buğdayı, Bintepe, Havrani, Çalıbasan, Hacı Halil, and Akçakale) compared to 2 well-established high-quality durum wheat cultivars, Kyle …


The Dynamics Of Reproductive Rate, Offspring Survivorship And Growth In The Lined Seahorse, Hippocampus Erectus Perry, 1810, Qiang Lin, Gang Li, Geng Qin, Liangmin Huang, Hushan Sun, Peiyong Feng Jan 2012

The Dynamics Of Reproductive Rate, Offspring Survivorship And Growth In The Lined Seahorse, Hippocampus Erectus Perry, 1810, Qiang Lin, Gang Li, Geng Qin, Liangmin Huang, Hushan Sun, Peiyong Feng

Ocean Engineering and Marine Sciences Faculty Publications

Seahorses are the vertebrate group with the embryonic development occurring within a special pouch in males. To understand the reproductive efficiency of the lined seahorse, Hippocampus erectus Perry, 1810 under controlled breeding experiments, we investigated the dynamics of reproductive rate, offspring survivorship and growth over births by the same male seahorses. The mean brood size of the 1-year old pairs in the 1st birth was 85.4±56.9 per brood, which was significantly smaller than that in the 6th birth (465.9±136.4 per brood) (P<0.001). The offspring survivorship and growth rate increased with the births. The fecundity was positively correlated with the length of brood pouches of males and trunk of females. The fecundity of 1-year old male and 2-year old female pairs was significantly higher than that from 1-year old couples (P<0.001). The brood size (552.7±150.4) of the males who mated with females that were isolated for the gamete-preparation, was larger than those (467.8±141.2) from the long-term pairs (P<0.05). Moreover, the offspring from the isolated females had higher survival and growth rates. Our results showed that the potential reproductive rate of seahorses H. erectus increased with the brood pouch development.


Climate-Change Refugia In The Sheltered Bays Of Palau: Analogs Of Future Reefs, Robert Van Woesik, Peter Houk, Adelle L. Isechal, Jacques W. Idechong, Steven Victor, Yimnang Golbuu Jan 2012

Climate-Change Refugia In The Sheltered Bays Of Palau: Analogs Of Future Reefs, Robert Van Woesik, Peter Houk, Adelle L. Isechal, Jacques W. Idechong, Steven Victor, Yimnang Golbuu

Ocean Engineering and Marine Sciences Faculty Publications

Coral bleaching and mortality are predicted to increase as climate changeinduced thermal-stress events become more frequent. Although many studies document coral bleaching and mortality patterns, few studies have examined deviations from the expected positive relationships among thermal stress, coral bleaching, and coral mortality. This study examined the response of >30,000 coral colonies at 80 sites in Palau, during a regional thermal-stress event in 2010. We sought to determine the spatial and taxonomic nature of bleaching and examine whether any habitats were comparatively resistant to thermal stress. Bleaching was most severe in the northwestern lagoon, in accordance with satellite-derived maximum temperatures …


Catastrophe And The Life Span Of Coral Reefs, Richard B. Aronson, William F. Precht, Ian G. Macintyre, Lauren T. Toth Jan 2012

Catastrophe And The Life Span Of Coral Reefs, Richard B. Aronson, William F. Precht, Ian G. Macintyre, Lauren T. Toth

Ocean Engineering and Marine Sciences Faculty Publications

A strong earthquake in the western Caribbean in 2009 had a catastrophic impact on uncemented, unconsolidated coral reefs in the central sector of the shelf lagoon of the Belizean barrier reef. In a set of 21 reef sites that had been observed prior to the earthquake, the benthic assemblages of 10 were eradicated, and one was partially damaged, by avalanching of their slopes. Ecological dynamics that had played out over the previous 23 years, including the mass mortalities of two sequentially dominant coral species and a large increase in the cover of an encrusting sponge, were instantaneously rendered moot in …


Summer And Migrational Movements Of Satellite-Marked Doublecrested Cormorants From A Breeding Colony Managed By Egg-Oiling In Lake Ontario, Usa, Brian S. Dorr, Jimmy D. Taylor Ii, Scott J. Werner, D. Tommy King, James F. Farquhar, Irene M. Mazzocchi, Russell D. Mccullough Jan 2012

Summer And Migrational Movements Of Satellite-Marked Doublecrested Cormorants From A Breeding Colony Managed By Egg-Oiling In Lake Ontario, Usa, Brian S. Dorr, Jimmy D. Taylor Ii, Scott J. Werner, D. Tommy King, James F. Farquhar, Irene M. Mazzocchi, Russell D. Mccullough

United States Department of Agriculture Wildlife Services: Staff Publications

A two-year satellite telemetry study was initiated in May 2000 at a Double-crested Cormorant (Phalacrocorax auritus) breeding colony on Little Galloo Island (LGI) in eastern Lake Ontario, New York, USA, which is managed by egg-oiling. The objective was to describe cormorant (N = 26/year) movements, specifically during the period of reproductive management by egg-oiling and seasonally (breeding, migration and wintering). Egg-oiling at two-week intervals resulted in a hatch success on LGI of 5.7% for 2000 and 2001, combined. The majority (97%) of core use areas of marked cormorants contained LGI throughout three egg-oiling treatments (six weeks), and 71% …


Site Use Of European Starlings Wintering In Central New Jersey, H. Jeffrey Homan, Anthony A. Slowik, Linda B. Penry, George M. Linz, Wendy Anderson Jan 2012

Site Use Of European Starlings Wintering In Central New Jersey, H. Jeffrey Homan, Anthony A. Slowik, Linda B. Penry, George M. Linz, Wendy Anderson

United States Department of Agriculture Wildlife Services: Staff Publications

Managing European starlings with DRC-1339 near urban and suburban areas can lead to adverse publicity resulting from encounters by the public with dead and dying birds. Collectors could retrieve the birds, if the likely sites of mass mortalities were known. In December 2009, we radio tagged 50 starlings at 3 sites in central New Jersey and studied their movements and behavior. Two of the sites were ensconced in a mosaic of suburban and urban habitats, whereas the other was in a rural setting. The sites were selected from a list of agricultural producers that had requested assistance from the Wildlife …


Brown Midrib2 (Bmr2) Encodes The Major 4-Coumarate: Coenzyme A Ligase Involved In Lignin Biosynthesis In Sorghum (Sorghum Bicolor (L.) Moench), Ana Saballos, Scott Sattler, Emiliano Sanchez, Timothy P. Foster, Zhanguo Xin, Chulhee Kang, Jeffrey F. Pedersen, Wilfred Vermerris Jan 2012

Brown Midrib2 (Bmr2) Encodes The Major 4-Coumarate: Coenzyme A Ligase Involved In Lignin Biosynthesis In Sorghum (Sorghum Bicolor (L.) Moench), Ana Saballos, Scott Sattler, Emiliano Sanchez, Timothy P. Foster, Zhanguo Xin, Chulhee Kang, Jeffrey F. Pedersen, Wilfred Vermerris

Department of Agronomy and Horticulture: Faculty Publications

Successful modification of plant cell-wall composition without compromising plant integrity is dependent on being able to modify the expression of specific genes, but this can be very challenging when the target genes are members of multigene families. 4-coumarate:CoA ligase (4CL) catalyzes the formation of 4-coumaroyl CoA, a precursor of both flavonoids and monolignols, and is an attractive target for transgenic down-regulation aimed at improving agro-industrial properties. Inconsistent phenotypes of transgenic plants have been attributed to variable levels of down-regulation of multiple 4CL genes. Phylogenetic analysis of the sorghum genome revealed 24 4CL(-like) proteins, five of which cluster with bona fide …


Advances In Genome Sequencing And Genotyping Technology For Soybean Diversity Analysis, David L. Hyten Jan 2012

Advances In Genome Sequencing And Genotyping Technology For Soybean Diversity Analysis, David L. Hyten

Department of Agronomy and Horticulture: Faculty Publications

The completion of a soybean draft whole genome sequence along with advances in sequencing and genotyping technologies are creating a revolution in soybean genomics. The draft whole genome sequence of soybean is allowing researchers to fully take advantage of this new technology and is rapidly changing how soybean germ plasm is mined. Genetic markers such as SNPs can be quickly identified by using next generation sequencing and assayed on a large number of materials using advanced technologies that can genotype tens of thousands of markers on thousands of individuals very rapidly. This ability to qUickly identify and genotype genetic diversity …


Signals From Intraventricular Depth Electrodes Can Control A Brain-Computer Interface, Jerry J. Shih, Dean J. Krusienski Jan 2012

Signals From Intraventricular Depth Electrodes Can Control A Brain-Computer Interface, Jerry J. Shih, Dean J. Krusienski

Electrical & Computer Engineering Faculty Publications

A Brain-Computer Interface (BCI) is a device that enables severely disabled people to communicate and interact with their environments using their brain waves. Most research investigating BCI in humans have used scalp-recorded electroencephalography (EEG). We have recently demonstrated that signals from intracranial electrocorticography (ECoG) and stereotactic depth electrodes (SDE) in the hippocampus can be used to control a BCI P300 Speller paradigm. We report a case in which stereotactic depth electrodes positioned in the ventricle were able to obtain viable signals for a BCI. Our results demonstrate that event-related potentials from intraventricular electrodes can be used to reliably control the …


An Investigation Of Reflective Mulches For Use Over Capillary Mat Systems For Winter-Time Greenhouse Strawberry Production, George E. Meyer, Ellen T. Paparozzi, Elizabeth Walter-Shea, Erin E. Blankenship, Stacy A. Adams Jan 2012

An Investigation Of Reflective Mulches For Use Over Capillary Mat Systems For Winter-Time Greenhouse Strawberry Production, George E. Meyer, Ellen T. Paparozzi, Elizabeth Walter-Shea, Erin E. Blankenship, Stacy A. Adams

Department of Agronomy and Horticulture: Faculty Publications

Photosynthethically active radiation (PAR) is a principle environmental variable used by horticultural specialists, agronomists and ecosystem modelers to characterize the quantity and quality of light conducive to plant growth and development. Spatial distribution of PAR in a greenhouse can be quite variable and diffuse throughout the day time photoperiod, especially at low sun angles in northern regions of the United States. Four colors of reflective plastic mulches (white, red, olive, and black) were evaluated for winter-time strawberry (Fragaria × ananassa Duch.) production based on their reflectance and transmittance properties in a double-polyethylene, plastic-glazed Quonset greenhouse inNebraska. The spectral properties …


Inheritance Of Grain Polyphenol Oxidase (Ppo) Activity In Multiple Wheat (Triticum Aestivum L.) Genetic Backgrounds, Somrudee Nilthong, Robert A. Graybosch, P. Stephen Baenziger Jan 2012

Inheritance Of Grain Polyphenol Oxidase (Ppo) Activity In Multiple Wheat (Triticum Aestivum L.) Genetic Backgrounds, Somrudee Nilthong, Robert A. Graybosch, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Grain polyphenol oxidase (PPO) activity can cause discoloration of wheat (Triticum aestivum L.) food products. Five crosses (PI 117635/Antelope; Fielder/ NW03681; Fielder/Antelope; NW07OR1070/Antelope; NW07OR1066/OR2050272H) were selected to study the genetic inheritance of PPO activity. STS markers, PPO18, PPO29 and STS01, were used to identify lines with putative alleles at the Ppo-A1 and Ppo-D1 loci conditioning low or high PPO activity. ANOVA showed significant genotypic effects on PPO activity (P\0.0001) in all populations. The generations and generation 9 genotype effects were not significant in any population. A putative third (null) genotype at Ppo-A1 (no PCR fragments for PPO18) was discovered …


Identification And Characterization Of Four Missense Mutations In Brown Midrib 12 (Bmr12), The Caffeic O-Methyltranferase (Comt) Of Sorghum, Scott E. Sattler, Nathan A. Palmer, Ana Saballos, Ann M. Greene, Zhanguo Xin, Gautam Sarath, Wilfred Vermerris, Jeffrey F. Pedersen Jan 2012

Identification And Characterization Of Four Missense Mutations In Brown Midrib 12 (Bmr12), The Caffeic O-Methyltranferase (Comt) Of Sorghum, Scott E. Sattler, Nathan A. Palmer, Ana Saballos, Ann M. Greene, Zhanguo Xin, Gautam Sarath, Wilfred Vermerris, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Modifying lignin content and composition are targets to improve bioenergy crops for cellulosic conversion to biofuels. In sorghum and other C4 grasses, the brown midrib mutants have been shown to reduce lignin content and alter its composition. Bmr12 encodes the sorghum caffeic O-methyltransferase, which catalyzes the penultimate step in monolignol biosynthesis. From an EMS-mutagenized TILLING population, four bmr12 mutants were isolated. DNA sequencing identified the four missense mutations in the Bmr12 coding region, which changed evolutionarily conserved amino acids Ala71Val, Pro150Leu, Gly225Asp, and Gly325Ser. The previously characterized bmr12 mutants all contain premature stop codons. These newly identified mutants, along …


Cultivating A Movement: Excerpts From An Oral History Of Organic Farming And Sustainable Agriculture On California’S Central Coast [Book Review], Charles A. Francis Jan 2012

Cultivating A Movement: Excerpts From An Oral History Of Organic Farming And Sustainable Agriculture On California’S Central Coast [Book Review], Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

Edited by I. Reti and S. Rabkin, 2011. University of California, Santa Cruz, Library, Santa Cruz, California, United States. 299 p., US$19.95, ISBN 9-780972-33431, paper.

Often the most compelling evidence for success of organic farming comes from the personal stories of farmers. Coupled with reports on the application of science in organics, the practical knowledge of people in the field provides a rich foundation for the ongoing growth of this intriguing sector of the food system. This collection of interviews by the staff of the Regional History Project is one unique activity of the University of California, Santa Cruz library, …


Agriculture And Food In Crisis: Conflict, Resistance, And Renewal [Book Review], Charles A. Francis Jan 2012

Agriculture And Food In Crisis: Conflict, Resistance, And Renewal [Book Review], Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

Edited by Fred Magdoff and Brian Tokar. 2010. Monthly Review Press, New York, New York, United States. 348 p. Paperback, cloth US$ 75.00, paper US$ 18.95, ISBN-13 978-1-58367-226-6.

That doubling of food production over the next four decades will be needed to adequately nourish our human population is not news, but the incredible steps essential to achieve that goal and their political and social implications are less well reported. In this series of 16 essays edited by Fred Magdoff and Brian Tokar, several thoughtful specialists in global food issues explore the historical, biological, economic, energy, political and social dimensions of …


Estimating Construction Costs For A Low-Cost Quonset-Style Greenhouse, David P. Lambe, Stacy A. Adams, Ellen T. Paparozzi Jan 2012

Estimating Construction Costs For A Low-Cost Quonset-Style Greenhouse, David P. Lambe, Stacy A. Adams, Ellen T. Paparozzi

Department of Agronomy and Horticulture: Faculty Publications

Double polyethylene Quonset-style greenhouses offergrowers and farmers a more cost-effective structure than glass- or acrylic-covered structures for growing plants off-season. These greenhouses are especially applicablefor producing off-season high value crops such as fruits and vegetables for local markets. To support this production alternative, this publication contains a list of greenhouse components, the start-up costs associated with these items and an estimate of the number of person hours required to assemble and outfit a 24-foot-by-72-foot double polyethylene, air-inflated greenhouse structure. As there are many options available for building double polyethylene greenhouses, the main purpose of this publication is to identify the …


Biomass Yield And Nutrient Removal Rates Of Perennial Grasses Under Nitrogen Fertilization, M. K. Kering, T. J. Butler, J. T. Biermacher, John A. Guretzky Jan 2012

Biomass Yield And Nutrient Removal Rates Of Perennial Grasses Under Nitrogen Fertilization, M. K. Kering, T. J. Butler, J. T. Biermacher, John A. Guretzky

Department of Agronomy and Horticulture: Faculty Publications

Perennial grasses may provide a renewable source of biomass for energy production. Biomass yield, nutrient concentrations, and nutrient removal rates of switchgrass (Panicum virgatum L.), giant miscanthus (Miscanthus x giganteus), giant reed (Arundo donax L.), weeping lovegrass [Eragrostis curvula (Shrad.) Nees], kleingrass (Panicum coloratum L.), and Johnsongrass (Sorghum halepense (L.) Pers.) were evaluated at four N fertilizer rates (0, 56, 112, or 168 kg Nha−1) on a Minco fine sandy loam soil in southern Oklahoma. Species were established in 2008 and harvested for biomass in winter of 2009 and 2010. Biomass …


Biomass Yield And Nutrient Responses Of Switchgrass To Phosphorus Application, M. K. Kering, J. T. Biermacher, T. J. Butler, J. Mosali, John A. Guretzky Jan 2012

Biomass Yield And Nutrient Responses Of Switchgrass To Phosphorus Application, M. K. Kering, J. T. Biermacher, T. J. Butler, J. Mosali, John A. Guretzky

Department of Agronomy and Horticulture: Faculty Publications

Increasing desire for renewable energy sources has increased research on biomass energy crops in marginal areas with low potential for food and fiber crop production. In this study, experiments were established on low phosphorus (P) soils in southern Oklahoma, USA to determine switchgrass biomass yield, nutrient concentrations, and nutrient removal responses to P and nitrogen (N) fertilizer application. Four P rates (0, 15, 30, and 45 kg Pha−1) and two N fertilizer rates (0 and 135 kg Nha−1) were evaluated at two locations (Ardmore and Waurika) for 3 years.While P fertilization had no effect on yield …


Managing Nitrogen And Phosphorus Nutrients For Switchgrass Produced For Bioenergy Feedstock In Phosphorus-Deficient Soil, Mohua Haque, Jon T. Biermacher, Maru Kering, John A. Guretzky Jan 2012

Managing Nitrogen And Phosphorus Nutrients For Switchgrass Produced For Bioenergy Feedstock In Phosphorus-Deficient Soil, Mohua Haque, Jon T. Biermacher, Maru Kering, John A. Guretzky

Department of Agronomy and Horticulture: Faculty Publications

There is limited information available explaining the agronomic and economic relationships between yield and nitrogen and phosphorus applications to growing switchgrass produced in phosphorus-deficient soils. The objective of this study was to determine the effects of nitrogen and phosphorus fertilizers on feedstock yield and measures of expected total cost, gross revenue, net return, and breakeven price of feedstock produced in phosphorus-deficient soils in the southern Great Plains. Data were collected from a three-year, two-location agronomic field study conducted in south-central Oklahoma. Two discrete nitrogen treatments (0 and 134 kg ha-1) and four discrete phosphorus treatments (0, 30, 60 …


Modulation Of Kernel Storage Proteins In Grain Sorghum (Sorghum Bicolor (L.) Moench), Tejinder Kumar, Ismail M. Dweikat, Shirley Sato, Zhengxiang Ge, Natalya Nersesian, Han Chen, Thomas Elthon, Scott Bean, Brian P. Ioerger, Mike Tilley, Thomas E. Clemente Jan 2012

Modulation Of Kernel Storage Proteins In Grain Sorghum (Sorghum Bicolor (L.) Moench), Tejinder Kumar, Ismail M. Dweikat, Shirley Sato, Zhengxiang Ge, Natalya Nersesian, Han Chen, Thomas Elthon, Scott Bean, Brian P. Ioerger, Mike Tilley, Thomas E. Clemente

Department of Agronomy and Horticulture: Faculty Publications

Sorghum prolamins, termed kafirins, are categorized into subgroups α, β, and γ. The kafirins are co-translationally translocated to the endoplasmic reticulum (ER) where they are assembled into discrete protein bodies that tend to be poorly digestible with low functionality in food and feed applications. As a means to address the issues surrounding functionality and digestibility in sorghum, we employed a biotechnology approach that is designed to alter protein body structure, with the concomitant synthesis of a co-protein in the endosperm fraction of the grain. Wherein perturbation of protein body architecture may provide a route to impact digestibility by reducing disulphide …


Cover Crop Mixtures For The Western Corn Belt: Opportunities For Increased Productivity And Stability, Samuel E. Wortman, Charles A. Francis, John L. Lindquist Jan 2012

Cover Crop Mixtures For The Western Corn Belt: Opportunities For Increased Productivity And Stability, Samuel E. Wortman, Charles A. Francis, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Achieving agronomic and environmental benefits associated with cover crops oft en depends on reliable establishment of a highly productive cover crop community. The objective of this study was to determine if cover crop mixtures can increase productivity and stability compared to single species cover crops, and to identify those components most active in contributing to or detracting from mixture productivity. A rainfed field experiment was conducted near Mead, Nebraska, United States, in 2010 and 2011. Eight individual cover crop species (in either the Brassicaceae [mustard] or Fabaceae [legume] family) and four mixtures of these species (two, four, six, and eight …


Optimizing Cover Crop Benefits With Diverse Mixtures And An Alternative Termination Method, Samuel E. Wortman, Charles A. Francis, Mark L. Bernards, Rhae A. Drijber, John L. Lindquist Jan 2012

Optimizing Cover Crop Benefits With Diverse Mixtures And An Alternative Termination Method, Samuel E. Wortman, Charles A. Francis, Mark L. Bernards, Rhae A. Drijber, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Previous studies have demonstrated benefits of individual cover crop species, but the value of diverse cover crop mixtures has received less attention. The objectives of this research were to determine the effects of spring-sown cover crop mixture diversity and mechanical cover crop termination method on cover crop and/or cash crop productivity, soil moisture and N, and profitability in an organic cropping system. An experiment was conducted between 2009 and 2011 near Mead, Nebraska, United States, where mixtures of two (2CC), four (4CC), six (6CC), and eight (8CC) cover crop species, or a summer annual weed mixture were included in a …


Grazing On Synechococcus Spp. By The Red-Tide Dinoflagellate Karenia Brevis: Implications For Bloom Dynamics In The Gulf Of Mexico, Leo A. Procise Jan 2012

Grazing On Synechococcus Spp. By The Red-Tide Dinoflagellate Karenia Brevis: Implications For Bloom Dynamics In The Gulf Of Mexico, Leo A. Procise

OES Theses and Dissertations

Karenia brevis, the toxic dinoflagellate responsible for massive red tides in the Gulf of Mexico (GOM), causes fish kills, shellfish poisoning, and acute respiratory irritation in humans. Bloom initiation and maintenance have been linked to the physical environment as well as various nutrient input mechanisms. To date, efforts to quantify nitrogen (N) sources fueling K. brevis blooms in the GOM have not included mixotrophic grazing although many dinoflagellates, including K. brevis, are known to be capable of mixotrophy. This dissertation reports field and laboratory results demonstrating that natural bloom populations and K. brevisisolates from the West Florida …


An Epidemiological Model Of Rift Valley Fever With Spatial Dynamics, Tianchan Niu, Holly D. Gaff, Yiannis E. Papelis, David M. Hartley Jan 2012

An Epidemiological Model Of Rift Valley Fever With Spatial Dynamics, Tianchan Niu, Holly D. Gaff, Yiannis E. Papelis, David M. Hartley

Biological Sciences Faculty Publications

As a category A agent in the Center for Disease Control bioterrorism list, Rift Valley fever (RVF) is considered a major threat to the United States (USA). Should the pathogen be intentionally or unintentionally introduced to the continental USA, there is tremendous potential for economic damages due to loss of livestock, trade restrictions, and subsequent food supply chain disruptions. We have incorporated the effects of space into a mathematical model of RVF in order to study the dynamics of the pathogen spread as affected by the movement of humans, livestock, and mosquitoes. The model accounts for the horizontal transmission of …


In Vitro Propagation Of Candidatus Rickettsia Andeanae Isolated From Amblyomma Maculatum, Alison Luce-Fedrow, Chelsea Wright, Holly D. Gaff, Daniel E. Sonenshine, Wayne L. Hynes, Allen L. Richards Jan 2012

In Vitro Propagation Of Candidatus Rickettsia Andeanae Isolated From Amblyomma Maculatum, Alison Luce-Fedrow, Chelsea Wright, Holly D. Gaff, Daniel E. Sonenshine, Wayne L. Hynes, Allen L. Richards

Biological Sciences Faculty Publications

Candidatus Rickettsia andeanae was identified during an investigation of a febrile outbreak in northwestern Peru (2002). DNA sequencing from two ticks (Amblyomma maculatum, Ixodes boliviensis) collected during the investigation revealed a novel Rickettsia agent with similarity to the spotted fever group rickettsiae. Since then, Candidatus R. similar to andeanae has been detected in A. maculatum ticks collected in the southeastern and southcentral United States, Argentina, and Peru. To date, Candidatus R. andeanae has not been successfully cultivated in the laboratory. We present evidence for the continuous cultivation in three cell lines of Candidatus R. similar to …


Unusually High Body Mass In Virginia Meadow Voles, Sara B. Longtin, Robert K. Rose Jan 2012

Unusually High Body Mass In Virginia Meadow Voles, Sara B. Longtin, Robert K. Rose

Biological Sciences Faculty Publications

We used monthly capture-mark-recapture information to determine growth rates and life spans for 2 populations of meadow voles studied for 28 and 29 months in eastern Virginia in order to learn whether the exceptionally large body masses of some voles were due to rapid growth, long lives, or both. On 1 study grid, 64 males (19%) and 43 nonpregnant females (11%) were ≥70 g, with the largest male being 89 g. Mostly positive growth rates (averaging 1.1-3.9 g/month) were recorded, even in autumn and winter months, times when meadow voles are losing mass in northern populations, where most studies of …


Brooding, Provisioning, And Compensatory Care In The Cooperatively Breeding Acorn Woodpecker, Walter D. Koenig, Eric L. Walters Jan 2012

Brooding, Provisioning, And Compensatory Care In The Cooperatively Breeding Acorn Woodpecker, Walter D. Koenig, Eric L. Walters

Biological Sciences Faculty Publications

We analyzed reproductive investment in parental care (brooding and the provisioning of nestlings) in the acorn woodpecker (Melanerpes formicivorus), a cooperatively breeding species in which both polygynandry and helping-at-the-nest are common. As predicted based on the strategies pursued by birds of different sex and status, breeders generally invested more in parental care than helpers, and breeder females invested more than breeder males. Contrary to expectations, however, the degree to which individuals reduced their effort with increasing group size (i.e., patterns of load lightening or compensatory care) did not match overall investment. Instead, as group size increased, there was …


Molecular Phylogenetics Of Alternanthera (Gomphrenoideae, Amaranthaceae): Resolving A Complex Taxonomic History Caused By Different Interpretations Of Morphological Characters In A Lineage With C4 And C3-C4 Intermediate Species, Ivonne Sánchez-Del Pino, Timothy J. Motley, Thomas Borsch Jan 2012

Molecular Phylogenetics Of Alternanthera (Gomphrenoideae, Amaranthaceae): Resolving A Complex Taxonomic History Caused By Different Interpretations Of Morphological Characters In A Lineage With C4 And C3-C4 Intermediate Species, Ivonne Sánchez-Del Pino, Timothy J. Motley, Thomas Borsch

Biological Sciences Faculty Publications

Aternanthera (Amaranthaceae) is a diverse genus (80-200 species) largely restricted to the American Tropics. With Pedersenia and Tidestromia, it makes up the Alternantheroid clade in Gomphrenoideae. Parsimony and Bayesian analyses of nucleotide sequences of nuclear (ITS) and plastid (rpl16, trnL-F) and morphological characters identify that the capitate stigma of Alternanthera is a synapomorpy within the Alternantheroids. Within Alternanthera, two major clades were resolved, both of which were marked by otherwise homoplasious characters of the gynoecium: Clade A [99% jackknife (JK); 1.0 posterior probability (PP)] with nine species and Clade B (60% JK; 0.98 PP) with 22 …