Digital Commons Network^™

Associations Between Polycyclic Aromatic Hydrocarbon-Related Exposures And P53 Mutations In Breast Tumors, Irina Mordukhovich, Pavel Rossner Jr., Mary Beth Terry, Regina M. Santella, Yu-Jing Zhang, Hanina Hibshoosh, Lorenzo Memeo, Mahesh Mansukhani, Chang-Min Long, Gail Garbowski, Meenakshi Agrawal, Mia M. Gaudet, Susan E. Steck, Sharon K. Sagiv, Sybil M. Eng, Susan L. Teitelbaum, Alfred I. Neugut, Kathleen Conway-Dorsey, Marilie D. Gammon

Faculty Publications

BACKGROUND: Previous studies have suggested that polycyclic aromatic hydrocarbons (PAHs) may be associated with breast cancer. However, the carcinogenicity of PAHs on the human breast remains unclear. Certain carcinogens may be associated with specific mutation patterns in the p53 tumor suppressor gene, thereby contributing information about disease etiology.

OBJECTIVES: We hypothesized that associations of PAH-related exposures with breast cancer would differ according to tumor p53 mutation status, effect, type, and number.

METHODS: We examined this possibility in a population-based case–control study using polytomous logistic regression. As previously reported, 151 p53 mutations among 859 tumors were identified using Surveyor nuclease and …

Parental Entitlement And Corporal Punishment, James G. Dwyer

Faculty Publications

No abstract provided.

Synergistic Solutions: An Integrated Approach To Solving The Caregiver Conundrum For "Real" Workers, Nicole Buonocore Porter

Faculty Publications

This Article is the second part of a project aimed at ending caregiver discrimination for all workers who are struggling to balance work and family. The first part of the project argued that the communitarian theory supports the broad reform envisioned, and this piece articulates that vision. This reform project utilizes a synergy of solutions, taking a comprehensive and creative approach to ending the caregiver conundrum for all working caregivers. The proposal includes the use of various statutory provisions that work together to avoid some of the deficiencies created by other proposals. Specifically, the proposal attempts to address the three …

Virus-Triggered Ubiquitination Of Traf3/6 By Ciap1/2 Is Essential For Induction Of Interferon- &Beta (Ifn-&Beta) And Cellular Antiviral Response, Ai-Ping Mao, Shu Li, Bo Zhong, Ying Li, Jie Yan, Qi Li, Chengwen Teng Pharm.D.. Ph.D, Hong-Bing Shu

Faculty Publications

Viral infection causes activation of transcription factors NF-κB and IRF3, which collaborate to induce type I interferons (IFNs) and cellular antiviral response. Here we show that knockdown of the E3 ubiquitin ligases cIAP1 and cIAP2 markedly inhibited virus-triggered activation of IRF3 and NF-κB as well as IFN-β induction. Knockdown of cIAP1 and cIAP2 also inhibited cytoplasmic dsRNA-triggered cellular antiviral response. Endogenous coimmunoprecipitation experiments indicated that viral infection caused recruitment of cIAP1 and cIAP2 to TRAF3, TRAF6, and VISA. Furthermore, we demonstrated that cIAP1- and cIAP2-mediated virus-triggered ubiquitination of TRAF3 and TRAF6. These findings suggest that virus-triggered ubiquitination of TRAF3 and …

Processes Influencing Seasonal Hypoxia In The Northern California Current System, Thomas Connolly, Barbara Hickey, S. Geier, William Cochlan

Faculty Publications

This paper delineates the role of physical and biological processes contributing to hypoxia, dissolved oxygen (DO) < 1.4 mL/L, over the continental shelf of Washington State in the northern portion of the California Current System. In the historical record (1950–1986), during the summer upwelling season, hypoxia is more prevalent and severe off Washington than further south off northern Oregon. Recent data (2003–2005) show that hypoxia over the Washington shelf occurred at levels previously observed in the historical data. The year 2006 was an exception, with hypoxia covering ∼5000 km2 of the Washington continental shelf and DO concentrations below 0.5 mL/L at the inner shelf, lower than any known previous observations at that location. In the 4 years studied, upwelling of low DO water and changes in source water contribute to interannual variability, but cannot account for seasonal decreases below hypoxic concentrations. Deficits of DO along salinity surfaces, indicating biochemical consumption of DO, vary significantly between surveys, accounting for additional decreases of 0.5–2.5 mL/L by late summer. DO consumption is associated with denitrification, an indicator of biochemical sediment processes. Mass balances of DO and nitrate show that biochemical processes in the water column and sediments each contribute ∼50% to the total consumption of DO in near-bottom water. At shorter than seasonal time scales on the inner shelf, along-shelf advection of hypoxic patches and cross-shelf advection of seasonal gradients are both shown to be important, changing DO concentrations by 1.5 mL/L or more over 5 days.

Preliminary Results Of Combining Low Frequency Low Intensity Ultrasound And Liposomal Drug Delivery To Treat Tumors In Rats, William G. Pitt, Ghaleb A. Husseini, Beverly L. Roeder, David Dickinson, David Warden, Jonathan Hartley, Peter Jones

Faculty Publications

Ultrasound is a convenient trigger for site-specific drug delivery in cancer therapy. Nanosized liposomes formulated from soy phosphatidyl choline, cholesterol, 1,2-distearoyl-sn-glycero3-phosphoethanolamine-N-[carboxy(polyethylene glycol)-2000] and alpha-tocopherol were loaded with Doxorubicin (Dox)using a pH gradient. The liposomal suspension was infused through the tail vein of BDIX rats possessing bilateral intradermal DHD/K12 tumors on their hind legs. Then 20-kHz ultrasound was applied to only one of the tumors for 15 minutes. This therapy was repeated weekly for 4 weeks. The results showed that in five of sixrats, the tumors regressed to non-measurable size within 4 weeks. A paired comparison of the normalized size of …

Potential For Misidentification Of Environmentally Persistent Free Radicals As Molecular Pollutants In Particulate Matter, Hieu Truong, Slawo Lomnicki, Barry Dellinger

Faculty Publications

Environmentally persistent free radicals (EPFRs) have been shown to form on the surfaces of various types of transition metal-containing particulate matter (PM), and it has been demonstrated they are capable of initiating adverse health impacts. Following sonification and solvent extraction for chemical analysis, they are partially converted to molecular species. Alcoholic solvents extracted the EPFRs with near 100% efficiency, while nonpolar hydrocarbon solvents exhibited < 20% efficiency and dichloromethane exhibited 20-55% efficiency. The extracted radicals reacted in solution to form multiple molecular reaction products including catechol, hydroquinone, phenol, chlorinated phenols, dibenzo-p-dioxin, and dibenzofuran. This suggests that EPFRs in environmental samples are indistinguishable from molecular pollutants and are subject to misidentification as molecular adsorbates when traditional extraction and chemical analysis methods are employed. On the basis of these findings, the origin of the toxicity of particulate matter contaminated with toxic organic compounds should be considered for re-evaluation to include the possibility that EPFRs may be a significant contributor, and the impact of some molecular pollutants may have been overestimated. © 2010 American Chemical Society.

Role Of Casein Kinase 1 In The Glucose Sensor-Mediated Signaling Pathway In Yeast, Satish Pasula, Samujjwal Chakraborty, Jae H. Choi, Jeong-Ho Kim

Faculty Publications

Background

In yeast, glucose-dependent degradation of the Mth1 protein, a corepressor of the glucose transporter gene (HXT) repressor Rgt1, is a crucial event enabling expression of several HXT. This event occurs through a signaling pathway that involves the Rgt2 and Snf3 glucose sensors and yeast casein kinase 1 and 2 (Yck1/2). In this study, we examined whether the glucose sensors directly couple with Yck1/2 to convert glucose binding into an intracellular signal that leads to the degradation of Mth1.

Results

High levels of glucose induce degradation of Mth1 through the Rgt2/Snf3 glucose signaling pathway. Fluorescence microscopy analysis …

Correlates Of Physical Activity In Black, Hispanic, And White Middle School Girls, Evelyn B. Kelly, Deborah Parra-Medina, Karin A. Pfeiffer, Marsha Dowda, Terry L. Conway, Larry S. Webber, Jared B. Jobe, Scott Going, Russell R. Pate

Faculty Publications

Background: A need exists to better understand multilevel influences on physical activity among diverse samples of girls. This study examined correlates of moderate-to-vigorous physical activity (MVPA) among adolescent girls from different racial/ethnic backgrounds. Methods: 1,180 6th grade girls (24.5% black, 15.7% Hispanic, and 59.8% white) completed a supervised self-administered questionnaire that measured hypothesized correlates of PA. MVPA data were collected for 6 days using the ActiGraph accelerometer. Hierarchical regression analysis was used to examine correlates of PA in each racial/ethnic group. Results: Hispanic girls (n=185) engaged in 21.7 minutes of MVPA per day, black girls (n=289) engaged in 19.5 minutes …

The Role Of Adaptive Trans-Generational Plasticity In Biological Invasions Of Plants, Andrew R. Dyer, Cynthia S. Brown, Erin K. Espeland, John K. Mckay, Harald Meimberg, Kevin J. Rice

Faculty Publications

High-impact biological invasions often involve establishment and spread in disturbed, high-resource patches followed by establishment and spread in biotically or abiotically stressful areas. Evolutionary change may be required for the second phase of invasion (establishment and spread in stressful areas) to occur. When species have low genetic diversity and short selection history, within-generation phenotypic plasticity is often cited as the mechanism through which spread across multiple habitat types can occur. We show that trans-generational plasticity (TGP) can result in pre-adapted progeny that exhibit traits associated with increased fitness both in high-resource patches and in stressful conditions. In the invasive sedge, …

In Vitro And In Vivo Assessment Of Pulmonary Risk Associated With Exposure To Combustion Generated Fine Particles, Baher Fahmy, Liren Ding, Dahui You, Slawo Lomnicki, Barry Dellinger, Stephania A. Cormier

Faculty Publications

Strong correlations exist between exposure to PM2.5 and adverse pulmonary effects. PM2.5 consists of fine (≤2.5μm) and ultrafine (≤0.1μm) particles with ultrafine particles accounting for >70% of the total particles. Environmentally persistent free radicals (EPFRs) have recently been identified in airborne PM2.5. To determine the adverse pulmonary effects of EPFRs associated with exposure to elevated levels of PM2.5, we engineered 2.5μm surrogate EPFR-particle systems. We demonstrated that EPFRs generated greater oxidative stress in vitro, which was partly responsible for the enhanced cytotoxicity following exposure. In vivo studies using rats exposed to EPFRs containing particles demonstrated minimal adverse pulmonary effects. Additional …

Mechanisms Of Apoptosis In Crustacea: What Conditions Induce Versus Suppress Cell Death?, Michael A. Menze, Grady Fortner, Suman Nag, Steven C. Hand

Faculty Publications

Arthropoda is the largest of all animal phyla and includes about 90% of extant species. Our knowledge about regulation of apoptosis in this phylum is largely based on findings for the fruit fly Drosophila melanogaster. Recent work with crustaceans shows that apoptotic proteins, and presumably mechanisms of cell death regulation, are more diverse in arthropods than appreciated based solely on the excellent work with fruit flies. Crustacean homologs exist for many major proteins in the apoptotic networks of mammals and D. melanogaster, but integration of these proteins into the physiology and pathophysiology of crustaceans is far from complete. Whether apoptosis …

Monitoring And First Discovery Of The Mexican Rice Borer Eoreuma Loftini (Lepidoptera: Crambidae) In Louisiana, N. A. Hummel, T. Hardy, T. E. Reagan, D. Pollet, C. Carlton, M. J. Stout, J. M. Beuzelin, W. Akbar, W. White

Faculty Publications

Eoreuma loftini has expanded its range from the LRGV to east Texas, and now into southwest Louisiana. LDAF and LSU AgCenter scientists forecast that natural and unintended artificial movement will result in the continued spread of E. loftini toward the heart of Louisiana's rice and sugarcane-growing regions. The 12-XII-2008 collection was the first confirmation of this pest in the state. By catching E. loftini early in its natural advancement into Louisiana, additional rapid and proactive responses will allow producers to become educated on the best management practices for the pest in sugarcane and rice. These best management practices include planting …

Biological Control Of Tropical Soda Apple (Solanaceae) In Florida: Post-Release Evaluation, J. Medal, N. Bustamante, W. Overholt, R. Diaz, P. Stansly, A. Roda, D. Amalin, K. Hibbard, R. Gaskalla, B. Sellers, S. Hight, J. Cuda

Faculty Publications

The leaf feeding beetle Gratiana boliviana was released on tropical soda apple plants in Sumter County, FL., in 2006. The beetles significantly defoliated the plants over the period of the summers of 2006 and 2007, and became well established in the area.

When Trees Grow Too Long: Investigating The Causes Of Highly Inaccurate Bayesian Branch-Length Estimates, Jeremy M. Brown, Shannon M. Hedtke, Alan R. Lemmon, Emily Moriarty Lemmon

Faculty Publications

A surprising number of recent Bayesian phylogenetic analyses contain branch-length estimates that are several orders of magnitude longer than corresponding maximum-likelihood estimates. The levels of divergence implied by such branch lengths are unreasonable for studies using biological data and are known to be false for studies using simulated data. We conducted additional Bayesian analyses and studied approximate-posterior surfaces to investigate the causes underlying these large errors. We manipulated the starting parameter values of the Markov chain Monte Carlo (MCMC) analyses, the moves used by the MCMC analyses, and the prior-probability distribution on branch lengths. We demonstrate that inaccurate branch-length estimates …

Evaluations Of A Novel Isolate Of Isaria Fumosorosea For Control Of The Asian Citrus Psyllid, Diaphorina Citri (Hemiptera: Psyllidae), Marjorie A. Hoy, Raghuwinder Singh, Michael E. Rogers

Faculty Publications

A fungal pathogen that killed adult Diaphorina citri Kuwayama (Asian citrus psyllid) in Florida citrus groves was isolated, characterized molecularly and morphologically and identified as a novel isolate of Isaria fumosorosea (Ifr) (= Paecilomyces fumosoroseus) from the Asian citrus psyllid (Ifr AsCP), but no concentration-mortality or time-response data were obtained. When adult psyllids were sprayed with spores at 28°C, time response (LT50) values of 111 and 102.5 h at spore concentrations of 1 × 107 and 1 × 108 spores/mL, respectively, were obtained. The LT99, was 167.4 and 174.6 h, respectively, for the 2 spore concentrations. After 192 h, the …

Response To Calcium Channel Blocker Therapy In Black Hypertensive Patients, Thu T. Nguyen, Jay S. Kaufman, Richard S. Cooper

Faculty Publications

No abstract provided.

Rapid Assessment Of Genetic Ancestry In Populations Of Unknown Origin By Genome-Wide Genotyping Of Pooled Samples, Charleston W.K. Chiang, Zofia K.Z. Gajdos, Joshua M. Korn, Finny G. Kuruvilla, Johannah L. Butler, Rachel Hackett, Candace Guiducci, Thutrang T. Nguyen, Rainford Wilks, Terrence Forrester, Christopher A. Haiman, Katherine D. Henderson, Loic Le Marchand, Brian E. Henderson, Mark R. Palmert, Colin A. Mckenzie, Helen N. Lyon, Richard S. Cooper, Xiaofeng Zhu, Joel N. Hirschhorn

Faculty Publications

As we move forward from the current generation of genome-wide association (GWA) studies, additional cohorts of different ancestries will be studied to increase power, fine map association signals, and generalize association results to additional populations. Knowledge of genetic ancestry as well as population substructure will become increasingly important for GWA studies in populations of unknown ancestry. Here we propose genotyping pooled DNA samples using genome-wide SNP arrays as a viable option to efficiently and inexpensively estimate admixture proportion and identify ancestry informative markers (AIMs) in populations of unknown origin. We constructed DNA pools from African American, Native Hawaiian, Latina, and …

An Electrochemical Cell For The Efficient Turn Around Of Wafer Working Electrodes, Nicholas Wozniak, Alyssa Frey, Lucas Osterbur, Timothy Boman, Jennifer R. Hampton

Faculty Publications

We present a new design for an electrochemical cell for use with wafer working electrodes. The key feature of the design is the use of half turn thumb screws to form a liquid-tight seal between an o-ring and the sample surface. The assembly or disassembly of the cell requires a half turn of each thumb screw, which facilitates the quick turn around of wafer samples. The electrochemical performance of the cell is demonstrated by cyclic voltammetry and double step chronoamperometry measurements of the ferricyanide/ferrocyanide couple.

Organismal Climatology: Analyzing Environmental Variability At Scales Relevant To Physiological Stress, Brian Helmuth, Bernardo R. Broitman, Lauren Yamane, Sarah E. Gilman, Katharine Mach, K. A.S. Mislan, Mark W. Denny

Faculty Publications

Predicting when, where and with what magnitude climate change is likely to affect the fitness, abundance and distribution of organisms and the functioning of ecosystems has emerged as a high priority for scientists and resource managers. However, even in cases where we have detailed knowledge of current species’ range boundaries, we often do not understand what, if any, aspects of weather and climate act to set these limits. This shortcoming significantly curtails our capacity to predict potential future range shifts in response to climate change, especially since the factors that set range boundaries under those novel conditions may be different …

Beyond Affymetrix Arrays: Expanding The Set Of Known Hybridization Isotherms And Observing Pre-Wash Signal Intensities, Alexander Pozhitkov, Idrissa Boube, Marius Brouwer, Peter A. Noble

Faculty Publications

Microarray hybridization studies have attributed the nonlinearity of hybridization isotherms to probe saturation and post-hybridization washing. Both processes are thought to distort 'true' target abundance because immobilized probes are saturated with excess target and stringent washing removes loosely bound targets. Yet the paucity of studies aimed at understanding hybridization and dissociation makes it difficult to align physicochemical theory to microarray results. To fill the void, we first examined hybridization isotherms generated on different microarray platforms using a ribosomal RNA target and then investigated hybridization signals at equilibrium and after stringent wash. Hybridization signal at equilibrium was achieved by treating the …

Foraging-Related Activity Of Bald Eagles At A Washington Seabird Colony And Seal Rookery, James L. Hayward, Joseph G. Galusha, Shandelle M. Henson

Faculty Publications

From 1980 to 1998, Washington's Bald Eagle (Haliaeetus leucocephalus) population increased at an annual rate of 10. Over the same time period, foraging activity of Bald Eagles at marine bird breeding colonies also increased. From 1993 to 2008, we observed foraging-related behavior of Bald Eagles on Violet Point, Protection Island. This island hosts more than 70 of the breeding seabirds in Washington's inner seaways and serves as an important rookery for harbor seals (Phoca vitulina). We found that (1) eagles landed more frequently in seal haul-out (beach) areas than in gull-nesting (non-beach) areas of Violet Point, and that subadult eagles …

The Effects Of Theaflavin-Enriched Black Tea Extract On Muscle Soreness, Oxidative Stress, Inflammation, And Endocrine Responses To Acute Anaerobic Interval Training: A Randomized, Double-Blind, Crossover Study, Shawn M. Arent, Meghan Senso, Devon L. Golem, Kenneth H. Mckeever

Faculty Publications

Background: Muscle soreness and decreased performance often follow a bout of high-intensity exercise. By reducing these effects, an athlete can train more frequently and increase long-term performance. The purpose of this study is to examine whether a high-potency, black tea extract (BTE) alters the delayed onset muscle soreness (DOMS), oxidative stress, inflammation, and cortisol (CORT) responses to high-intensity anaerobic exercise.Methods: College-age males (N = 18) with 1+ yrs of weight training experience completed a double-blind, placebo-controlled, crossover study. Subjects consumed the BTE (1,760 mg BTE·d-1) or placebo (PLA) for 9 days. Each subject completed two testing sessions (T1 and T2), …

Structural Studies Of Bacterioferritin B From Pseudomonas Aeruginosa Suggest A Gating Mechanism For Iron Uptake Via The Ferroxidase Center, Saroja K. Weeratunga, Scott Lovell, Huili Yao, Kevin P. Battaile, Christopher J. Fischer, Casey E. Gee, Mario Rivera

Faculty Publications

The structure of recombinant Pseudomonas aeruginosa bacterioferritin B (Pa BfrB) has been determined from crystals grown from protein devoid of core mineral iron (as-isolated) and from protein mineralized with ≃600 iron atoms (mineralized). Structures were also obtained from crystals grown from mineralized BfrB after they had been soaked in an FeSO4 solution (Fe soak) and in separate experiments after they had been soaked in an FeSO 4 solution followed by a soak in a crystallization solution (double soak). Although the structures consist of a typical bacterioferritin fold comprised of a nearly spherical 24-mer assembly that binds 12 heme molecules, comparison …

Development And Verification Of An Analytical Algorithm To Predict Absorbed Dose Distributions In Ocular Proton Therapy Using Monte Carlo Simulations, Nicholas C. Koch, Wayne D. Newhauser

Faculty Publications

Proton beam radiotherapy is an effective and non-invasive treatment for uveal melanoma. Recent research efforts have focused on improving the dosimetric accuracy of treatment planning and overcoming the present limitation of relative analytical dose calculations. Monte Carlo algorithms have been shown to accurately predict dose per monitor unit (D/MU) values, but this has yet to be shown for analytical algorithms dedicated to ocular proton therapy, which are typically less computationally expensive than Monte Carlo algorithms. The objective of this study was to determine if an analytical method could predict absolute dose distributions and D/MU values for a variety of treatment …

A Duplicate Gene Rooting Of Seed Plants And The Phylogenetic Position Of Flowering Plants, Sarah Mathews, Mark D. Clements, Mark A. Beilstein

Faculty Publications

Flowering plants represent the most significant branch in the tree of land plants, with respect to the number of extant species, their impact on the shaping of modern ecosystems and their economic importance. However, unlike so many persistent phylogenetic problems that have yielded to insights from DNA sequence data, the mystery surrounding the origin of angiosperms has deepened with the advent and advance of molecular systematics. Strong statistical support for competing hypotheses and recent novel trees from molecular data suggest that the accuracy of current molecular trees requires further testing. Analyses of phytochrome amino acids using a duplicate gene-rooting approach …

Organization, Structure, And Assembly Of Alpha-Carboxysomes Determined By Electron Cryotomography Of Intact Cells, Cristina V. Iancu, Dylan M. Morris, Zhicheng Dou, Sabine Heinhorst, Gordon C. Cannon, Grant J. Jensen

Faculty Publications

Carboxysomes are polyhedral inclusion bodies that play a key role in autotrophic metabolism in many bacteria. Using electron cryotomography, we examined carboxysomes in their native states within intact cells of three chemolithoautotrophic bacteria. We found that carboxysomes generally cluster into distinct groups within the cytoplasm, often in the immediate vicinity of polyphosphate granules, and a regular lattice of density frequently connects granules to nearby carboxysomes. Small granular bodies were also seen within carboxysomes. These observations suggest a functional relationship between carboxysomes and polyphosphate granules. Carboxysomes exhibited greater size, shape, and compositional variability in cells than in purified preparations. Finally, we …

Uncoupling Of Inflammation And Insulin Resistance By Nf-Κb In Transgenic Mice Through Elevated Energy Expenditure, Tianyi Tang, Jin Zhang, Jun Yin, Jaroslaw Staszkiewicz, Barbara Gawronska-Kozak, Dae Young Jung, Hwi Jin Ko, Helena Ong, Jason K. Kim, Randy Mynatt, Roy J. Martin, Michael Keenan, Zhanguo Gao, Jianping Ye

Faculty Publications

To study the metabolic activity of NF-κB, we investigated phenotypes of two different mouse models with elevated NF-κB activities. The transcriptional activity of NF-κB is enhanced either by overexpression of NF-κB p65 (RelA) in aP2-p65 mice or inactivation of NF-κBp50 (NF-κB1) through gene knock-out. In these models, energy expenditure was elevated in day and night time without a change in locomotion. The mice were resistant to adulthood obesity and diet-induced obesity without reduction in food intake. The adipose tissue growth and adipogenesis were inhibited by the elevated NF-κB activity. Peroxisome proliferator-activator receptor γ expression was reduced by NF-κB at the …

Reversibility Of Β-Amyloid Self-Assembly: Effects Of Ph And Added Salts Assessed By Fluorescence Photobleaching Recovery, Nadia J. Edwin, Robert P. Hammer, Robin L. Mccarley, Paul S. Russo

Faculty Publications

The 40-residue peptide isoform β-amyloid (Aβ1-40) is associated with Alzheimer's disease. Although found in the tangles and fibrous mats that characterize the brain in advanced stages of the disease, the toxic form of Aβ is believed to be oligomers or "protofibrils". Characterization of these fairly small structures in solution, especially in the presence of the much larger assemblies they also form, is a daunting task. Additionally, little is known about the rate of Aβ assembly or whether it can be triggered easily. Perhaps most importantly, the conditions for reversing assembly are not fully understood. Fluorescence photobleaching with modulation detection of …

Relationships Between Herbaceous Diversity And Biomass In Two Habitats In Arid Mediterranean Rangeland, Mohammad N. Alhamad, Brian P. Oswald, Mohammad M. Bataineh, Mohammad A. Alrababah, Mohammad M. Gharaibeh

Faculty Publications

Plant diversity patterns vary across the landscape. This study was conducted to answer the question: What is the pattern of species diversity (α and β) along an abstract productivity/cover gradient at two topographical positions (Wadi (a depression with overland flow) and hilltop) of a Mediterranean herbaceous plant community in Jordan? Results indicated that the less productive hilltop localities exhibited higher species richness than the more productive Wadi localities. Species richness exhibited a unimodal relationship with aboveground biomass within Wadis whereas a positive linear relationship was revealed for hilltops. Within Wadis, abundant species did not show a significant relationship with productivity …