Environmental Science

Rural and background sites provide valuable information on the concentration and optical properties of organic, elemental, and water-soluble organic carbon (OC, EC, and WSOC), which are relevant for understanding the climate forcing potential of regional atmospheric aerosols. To quantify climate-and air quality-relevant characteristics of carbonaceous aerosol in the central United States, a regional background site in central Texas was chosen for long-term measurement. Back trajectory (BT) analysis, ambient OC, EC, and WSOC concentrations and absorption parameters are reported for the first 15 months of a long-term campaign (May 2011-August 2012). BT analysis indicates consistent north-south airflow connecting central Texas to the Central Plains. Central Texas aerosols exhibited seasonal trends with increased fine particulate matter (<2.5 mm aerodynamic diameter, PM 2.5 ) and OC during the summer (PM 2.5 ¼ 10.9 mg m À3 and OC ¼ 3.0 mg m À3 ) and elevated EC during the winter (0.22 mg m À3 ). When compared to measurements in Dallas and Houston, TX, central Texas OC appears to have mixed urban and rural sources. However, central Texas EC appears to be dominated by transport of urban emissions. WSOC averaged 63% of the annual OC, with little seasonal variability in this ratio. To monitor brown carbon (BrC), absorption was measured for the aqueous WSOC extracts. Light absorption coefficients for EC and BrC were highest during summer (EC MAC ¼ 11 m 2 g À1 and BRC MAE 365 ¼ 0.15 m 2 g À1 ). Results from optical analysis indicate that regional aerosol absorption is mostly due to EC with summertime peaks in BrC attenuation. This study represents the first reported values of WSOC absorption, MAE 365 , for the central United States.

Many creatures , includ ing the myop ic rh inoceros, d epend upon h earing and s mell t o determine their environ ment. Natu re is do minat ed by b iophonic and geophon ic sounds qu ickly absorbed by so il and vegetat ion. Anthrophon ic u rban soundscapes exh ib it vast ly d ifferent physical and semant ic characterist ics : reflect ions fro m hard geo met ric surfaces , mu lt i-path p ropagat ion and reverberat ion , and o ften increased sound p ressure levels co mp ared to natu re, in addit ion to much anthropogen ic no ise not found in natu re. No ise damages hu mans physio log ically, includ ing reproduct iv ely, and likely damages other mammals. Rh inos vocalize sonically and in frasonically but aud iog rams are unavailab le. They generally b reed poorly in u rban zoos, where in frasonic no ise tends to b e c h ron ic. Bio log ical and social factors have been stud ied but litt le attent ion if an y has been paid to soundscape. To co mp rehens ively describe th e rh inos' acoustic env iron ment at Fossil Rim Wild life Center, one o f the few U.S. facilit ies to successfu lly breed wh ite rh inos in recent years , its broadband sound met rics were studied throughout a week o f no rmal park act iv it ies. Fu rther analys is will seek part icu lar parameters kno wn to be in ju rious to hu mans, p lus those already kno wn to invo ke response in an imals. Later, a v ariety o f other facilit ies cou ld be reco rded to seek co rrelat ions b etween their soundscapes and the health and well-being of the creatures within their care.

We describe the development of a simple model representing individual energetic and time budget activities of a nonbreeding American robin (Turdus migratorius). In the model, values for energetic costs and physical activity were derived from various literature sources, and are influenced by the proportion of time spent in each activity, time of day, and bird weight. We used multiple combinations of intake rates, foraging times and activity budgets to simulate weight dynamics. In our simulations, a robin had to forage between 21-50% of daylight hours merely to maintain its weight, far more than some studies predict. A robin gained weight by increasing time spent foraging, increasing food intake rates or decreasing flight activity. This model can be a useful tool in exploring the effects of various combinations of behavioral and energetic activities on robin weight. It can also serve as a baseline for future analyses involving the influence of various human activities in American robin behavior and weight dynamics.

ABSTRA..-As part of a project to determine optimal methods for censusing winter birds with unlimited-distance point counts, we studied the influence of wearing a hunter-orange vest on richness estimates and species&#39; detection probabilities. We did not find a significant difference in the number of species detected between apparel conditions (vest worn, vest not worn). However, separate detection probabilities for three species were associated with whether or not an orange vest was worn (Carolina Chickadee [Parus carolinensis, P = 0.075]; Tufted Titmouse [P. bicolor, P = 0.009]; American Goldfinch [Carduelis tristis, P = 0.002]). For all three species, detection probabilities were lower when a vest was worn, suggesting that these species were repelled by the orange vest. Movement toward or away from a color, respectively, may generate inaccurate assessments of behavior, habitat use, and abundance. Knowledge about chromotropic responses to observer apparel will enable investigator...

Human intrusion can be a serious problem for birds because it can cause displacement, prevent access to resources, and reduce reproduction and survival. The factors that influence avian tolerance to intrusion are poorly understood. We studied passerine responses to intrusion in Wyoming montane forests during the breeding season by using two indices of intrusion tolerance: detectability period, the amount of time that a bird remains near its initial flush point; and approach distance, how close one can get to a bird before it flushes. A solitary observer experimentally approached focal individuals and recorded detectability period, approach distance, the seasonal and daily timing of intrusion, number of nearby conspecifics, number of nearby heterospecific individuals, and surrounding vegetation conditions. Using data from the literature, we also assessed influences of migratory status, body mass, conspicuousness, and height above the ground at which species are active during the breeding season. Detectability period was significantly shorter, indicating intrtsion tolerance was lower, when fewer conspecifics were nearby. Approach distance was significantly longer, indicating tolerance was lower, for more-conspicuous species and for species that are active closer to the ground. Effects of other variables studied were not significant. These results demonstrate that social and biological factors can influence tolerance to intrusion. Intrusion-induced behaviors such as nest abandonment and decreased nest attentiveness have led to reduced reproduction and survival in species that are intolerant of intrusion. With knowledge of factors that influence tolerance, the risk of disturbing birds that are sensitive to intrusion could be reduced.

Primary roots of Zea mays cv. Yellow Dent growing in an electric field curve towards the anode. Roots treated with EDTA and growing in electric field do not curve. When root cap mucilage is applied asymmetrically to tips of vertically-oriented roots, the roots curve toward the mucilage. Roots treated with EDTA curve toward the side receiving mucilage and toward blocks containing 10 mM CaCl 2 , but not toward "empty" agar blocks or the cut surfaces of severed root tips. These results suggest that I) free calcium (Ca) is necessary for root electrotropism, 2) mucilage contains effector(s) that induce gravitropiclike curvature, and 3) mucilage can replace gravitropic effectors chelated by EDTA. These results are consistent with the hypothesis that the downward movement of gravitropic effectors to the lower sides of tips of horizontally-oriented roots occurs at least partially in the apoplast. RECENT STUDIES have implicated calcium (Ca) and electrical currents as mediators of root gravitropism (see reviews by Bjorkman, 1988; Bjorkman and Leopold, 1987; Moore and Evans, 1986). During graviperception, amyloplasts sediment to the lower sides ofcolumella cells of the root cap (Juniper, 1976; Wilkins, 1979). These amyloplasts may touch endoplasmic reticulum along the lower side of the cells, triggering the release of Ca 2 + from endoplasmic reticulum (see Evans, Moore, and Hasenstein, 1986). This gravity-induced redistribution of calcium may link graviperception and gravicurvature in roots (Lee, Mulkey, and Evans, 1984). This Ca2+ presumably binds with and activates calmodulin, which then activates pumps that move calcium and auxin out of the lower side of the root cap (Evans et aI., 1986). The accumulation of calcium along the lower side of the root cap may enhance the rate at which auxin in the lower side ofthe cap moves back to the lower side ofthe elongating zone (Evans et aI., 1986). The accumulation of auxin along the lower side ofa gravistimulated root inhibits cellular elongation there, causing the root to curve down (see discussion in Moore and Evans, 1986). Calcium is a primary effector of root gravitropism, and formation of a calcium gradient is apparently necessary for root gravicurvature I

With rapidly disappearing natural areas due to development and fragmentation, public lands provide important habitat for birds. However, the increasing use of public lands for recreation may decrease the value of these areas for bird use. Human disturbance can damage birds in many ways, including disrupting foraging or social behavior, increasing nest predation, interfering with parent-offspring and pair bonds, increasing nesting failures, and reducing the viability of fledglings. Additionally, birds may perceive humans as predators and leave an area, and the resulting decline in species abundance resembles the effects of habitat loss. Increased human outdoor activity has created the need for information regarding the effects of human disturbance on birds. I investigated the effects of human disturbance on birds in Bastrop State Park (BSP) in central Texas in 1998 and 1999. A wide variety of people use much of BSP, and many areas within the park experience significant amounts of disturbance from people and vehicles, particularly in campgrounds. I evaluated the effects of various types of human disturbance on the presence of 20 avian species, including seven neotropical migratory species. Brown-headed Cowbird (Molothrus ater), Mourning Dove (Zenaida v ACKNOWLEDGEMENTS I thank Dr. Keith Arnold for his dedication and devotion to excellence in scholarship, and for his unwavering faith in my abilities to earn this degree. Additionally, I offer thanks to my dissertation committee, who worked so willingly with me: Drs. William E. Grant, Nova J. Silvy and David Scott. They were always generous with their help, and I value their guidance and professionalism. I would like to thank Baylor University for giving me the time off so I could pursue my degree, without which I could not have advanced my career. I am grateful for my students who spent countless hours in the field with me, sharing my enthusiasm for this project. I thank the field technicians for their hard work during often brutal summer heat in rough conditions. I would like to acknowledge Dr. Kevin J. Gutzwiller, who was instrumental in urging me to strive for loftier goals, and who had faith in my abilities from the beginning. I am also indebted to the Texas Parks and Wildlife Department (Permit # 33-99), for allowing unlimited access to Bastrop State Park and for the considerable expertise and help of the staff. Finally, I thank my family, who supported me through the long process of my education. My love and gratitude go to my husband, Greg, who always supported my endeavors, and took the responsibility of running the household so I could pursue my degree. I am indebted to my sister, Mary, who did untold hours of chores that gave me the time to work on this project, and who provided great advice. Finally, I am ever grateful to my parents, who gifted me with a love of learning. vi

We describe the development of a simple model representing individual energetic and time budget activities of a nonbreeding American robin (Turdus migratorius). In the model, values for energetic costs and physical activity were derived from various literature sources, and are influenced by the proportion of time spent in each activity, time of day, and bird weight. We used multiple combinations of intake rates, foraging times and activity budgets to simulate weight dynamics. In our simulations, a robin had to forage between 21-50% of daylight hours merely to maintain its weight, far more than some studies predict. A robin gained weight by increasing time spent foraging, increasing food intake rates or decreasing flight activity. This model can be a useful tool in exploring the effects of various combinations of behavioral and energetic activities on robin weight. It can also serve as a baseline for future analyses involving the influence of various human activities in American robin behavior and weight dynamics.

With rapidly disappearing natural areas due to development and fragmentation, public lands provide important habitat for birds. However, the increasing use of public lands for recreation may decrease the value of these areas for bird use. Human disturbance can damage birds in many ways, including disrupting foraging or social behavior, increasing nest predation, interfering with parent-offspring and pair bonds, increasing nesting failures, and reducing the viability of fledglings. Additionally, birds may perceive humans as predators and leave an area, and the resulting decline in species abundance resembles the effects of habitat loss. Increased human outdoor activity has created the need for information regarding the effects of human disturbance on birds. I investigated the effects of human disturbance on birds in Bastrop State Park (BSP) in central Texas in 1998 and 1999. A wide variety of people use much of BSP, and many areas within the park experience significant amounts of disturbance from people and vehicles, particularly in campgrounds. I evaluated the effects of various types of human disturbance on the presence of 20 avian species, including seven neotropical migratory species. Brown-headed Cowbird (Molothrus ater), Mourning Dove (Zenaida v ACKNOWLEDGEMENTS I thank Dr. Keith Arnold for his dedication and devotion to excellence in scholarship, and for his unwavering faith in my abilities to earn this degree. Additionally, I offer thanks to my dissertation committee, who worked so willingly with me: Drs. William E. Grant, Nova J. Silvy and David Scott. They were always generous with their help, and I value their guidance and professionalism. I would like to thank Baylor University for giving me the time off so I could pursue my degree, without which I could not have advanced my career. I am grateful for my students who spent countless hours in the field with me, sharing my enthusiasm for this project. I thank the field technicians for their hard work during often brutal summer heat in rough conditions. I would like to acknowledge Dr. Kevin J. Gutzwiller, who was instrumental in urging me to strive for loftier goals, and who had faith in my abilities from the beginning. I am also indebted to the Texas Parks and Wildlife Department (Permit # 33-99), for allowing unlimited access to Bastrop State Park and for the considerable expertise and help of the staff. Finally, I thank my family, who supported me through the long process of my education. My love and gratitude go to my husband, Greg, who always supported my endeavors, and took the responsibility of running the household so I could pursue my degree. I am indebted to my sister, Mary, who did untold hours of chores that gave me the time to work on this project, and who provided great advice. Finally, I am ever grateful to my parents, who gifted me with a love of learning. vi

Angiotensin II (Ang) binding kinetics were determined in discrete brainstem nuclei of 14-week-old spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) by a quantitative autoradiographic technique. Tissue sections were incubated with 125I-labeled [sarcosine-l]Ang, and results were analyzed by computerized densitometry and comparison to '25I-labeled standards. A single class of high-affinity binding sites was identified in the nucleus tractus solitarius, the area postrema, and the inferior olivary nuclei of both SHR and WKY rats. Ang binding affinity was significantly greater in the nucleus tractus solitarius of SHR compared to normotensive WKY rats (0.27 ± 0.06 x 109

In the present world, where there are high technological advancements, there are serious issue of soil and water pollution with contaminants like heavy metals, antibiotics, hormones, dyes, and petroleum products. Hydroponic experiments were performed to test the ability of Brassica juncea to phytoremediate copper and ciprofloxacin. It was found that B.juncea can remediate higher concentrations (15-30 ppm) of copper more effectively as compared to higher concentrations of ciprofloxacin. In addition to this, it was also observed that lower concentrations (5-10 ppm) of ciprofloxacin can be remediated more effectively than lower concentrations of copper.

Pollution in water bodies and soil is a major and ever-increasing environmental issue nowadays, and most conventional remediation approaches do not provide appropriate solutions. The contamination of soil is a major concern for the environment and needs to be remediated. These pollutants include complex organic compounds, heavy metals released from industries and plants and natural products such as oils from accidental release. Further the nature of pollution will be governed by the source and type of the contaminant, and other inorganic compounds are released into the environment from a number of sources like mining, smelting, electroplating, and farming. Plants can clean up many types of contaminants like metals, pesticides, oils, and explosives. Phytoremediation is emerging as a bio-based and low-cost alternative in the cleanup of heavy metal-contaminated soils.