Assessing Mourning Dove Population Declines: Changes in Nesting Dynamics and the Role of Perch Sites

I replicated a nesting study carried out 40 years ago in southern Utah to assess reasons for long-term population declines of mourning doves (Zenaida macroura) in the western United States. I compared current nesting patterns to similar data collected in 1952. I saw little difference in nest success and nest predation, but reproductive output and nest density decreased dramatically. The number of young fledged per pair of adults was only 64% of that estimated in 1952. A 1-2 week delay in the nesting season contributed to this decrease, but cannot explain it entirely. Nest density was about 20% of that in 1952 and total reproductive output for the study area about 12-19%. Underlying causes for these changes are uncertain, but patterns of delayed nesting, high nest abandonments, and low reproductive output are similar to those seen in stressed bird populations (e.g., food/nutrient limitation or increased toxicant levels). Finally, highest nest density occurred in a habitat type (i.e., Chalk Creek) considered unimportant for doves in 1952. Nests in Chalk Creek suffered higher predation and abandonment rates than those in irrigation ditches. I also examined the effect of perch sites on nest density and distribution in two ways. First, I demonstrated a significant correlation between nest density and perch s:te density in riparian plots. Second, I erected artificial perch sites in the second year of the study and recorded changes in nest densities. For the year of the study only, nest density was higher in the experimental plots, but the difference was not statistically significant. From the levels recorded the previous year, however, nest densities increased in the experimental plots and decreased in the control plots. This difference was statistically significant, suggesting that mourning doves use the presence of perch sites as cues for habitat selection. Finally, in comparing the presence of other avian species, I found significantly more blackbirds (Aqelaius phoenicus and Euphaqus cyanocephalus) and western meadowlarks (Sturnella neglecta) in experimental plots than in control plots

A Comparative Analysis of Influenza Vaccination Programs

The threat of avian influenza and the 2004-2005 influenza vaccine supply shortage in the United States has sparked a debate about optimal vaccination strategies to reduce the burden of morbidity and mortality caused by the influenza virus. We present a comparative analysis of two classes of suggested vaccination strategies: mortality-based strategies that target high risk populations and morbidity-based that target high prevalence populations. Applying the methods of contact network epidemiology to a model of disease transmission in a large urban population, we evaluate the efficacy of these strategies across a wide range of viral transmission rates and for two different age-specific mortality distributions. We find that the optimal strategy depends critically on the viral transmission level (reproductive rate) of the virus: morbidity-based strategies outperform mortality-based strategies for moderately transmissible strains, while the reverse is true for highly transmissible strains. These results hold for a range of mortality rates reported for prior influenza epidemics and pandemics. Furthermore, we show that vaccination delays and multiple introductions of disease into the community have a more detrimental impact on morbidity-based strategies than mortality-based strategies. If public health officials have reasonable estimates of the viral transmission rate and the frequency of new introductions into the community prior to an outbreak, then these methods can guide the design of optimal vaccination priorities. When such information is unreliable or not available, as is often the case, this study recommends mortality-based vaccination priorities

A National Food-Crop Policy Model for Indonesia

From the implementation of the New Order government\u27s first five-year development plan (Repelita I) in 1969 until the mid-189s, the overriding objective of Indonesian food policy was to increase rice production so as to make the country self-sufficient, at a relatively high level of consumption, in its basic staple food. The goal of rice self-sufficiency was pursued through a centrally directed program of production and area targets, subsidized distribution of inputs with extension services, investment in irrigation and marketing infrastructure, and aremunerative floor price to farmers. With the achievement of rice self-sufficiency in 1985, the focus of Indonesia\u27s food policy was broadened to include the promotion of secondary food-crop production. But the basic mechanism of centrally directed supply targets and input distribution remained the means of encouraging diversification of the food-crop sector

Non-Operative Management of a Common Bile Duct Injury Sustained During Cholecystectomy in a Morbidly Obese Patient. (Non-Operative Repair of CBD Injury)

A 29 year old morbidly obese patient suffered injury to his common bile duct during cholecystectomy. Subsequent access to the biliary tree was obtained by using a long heavy gauge needle after first opacifying the system with contrast injection through a nasobiliary tube. It is now twenty six months after initial percutaneous biliary drainage placement and eighteen months after removal of all biliary access. The patient is asymptomatic and has normal liver function tests. This technique can be useful in morbidly obese patients who are at increased risk from surgical repair of biliary duct injuries

A Capstone Project on Robust Dynamic Positioning and Data Acquisition Systems

The United States Coast Guard is responsible for enforcing Dynamic Positioning System (DPS) standards in the maritime industry. It is important for the members of the U. S. Coast Guard to understand how these systems work. Students have gained a much greater understanding of how DPS platforms work and what might be required to maintain them by building one from scratch. Aside from this, the project has served as a great opportunity to work on a one year term project that may resemble engineering or acquisitions projects that might be encountered in the students’ future careers. The overall goal of the Robust Dynamic Positioning and Data Acquisition System project was to prototype a dynamic positioning system similar to the ones on buoy tenders in the fleet. The primary goal was to maintain a desired heading and position within a certain range. The secondary goals included robust capabilities (the ability to continue functioning despite motor failures) and data acquisition (to analyze system performance post-testing). Students built a vessel from scratch out of a salvage drum and an inner tube for buoyancy. The internal construction consists of three tiers containing batteries at the lowest level, an onboard computer at the second level, and control hardware at the top level (micro controllers, H-bridges, and fuse boxes). Students successfully used a light detection and ranging (LIDAR) device to determine the relative position to two stationary poles. They were able to communicate with the onboard computer via either a wired connection or a remote desktop connection through an ad-hoc wireless network. All programming for this project was done in MATLAB®. Students have completed all project milestones through the application of past courses they have taken in computer control systems, network communication, and digital signal processing at the U.S. Coast Guard Academy. The first challenge of this project was to focus on constructing the vessel and installing the control hardware. One of the obstacles for the students was establishing communication between the various pieces of software, hardware, and the power distribution system. The LIDAR sensor determined the vessel’s relative position and heading to two stationary poles. Using the position and heading resolution algorithms, students conducted a set of system identification tests in an indoor tank to determine how the system reacts to various thrusts from the motors. This allowed students to collect “Open-Loop” system data. Using the data acquisition system, students were able to identify the system and calculate coefficients for the controller and implement a “Closed- Loop” control system. Students successfully implemented a proportional integral derivative (PID) controller that satisfies all design requirements including robust functionality. Currently, all milestones for the project have been accomplished and plans for continuation of the project are underway

An investigation of Prussian Blue analogues by Mossbauer spectroscopy and magnetic susceptibility

The Mossbauer spectra and magnetic susceptibilities have been obtained for a series of Prussian Blue analogues of general formula MjA[MB(CN)6]k[middle dot]mH2O where MA and MB are transition metal ions, j and k vary with the oxidation states of MA and MB and m typically has values from 8 to 14. The compounds were prepared from the hexacyano acids or with large quaternary ammonium counterions and are therefore not contaminated with alkali cations. In each analogue, A or B is iron and the second metal is Mn, Cu, Co, Cr or Ru. In each case it was possible to assign the site (A or B), oxidation state and spin state to each transition metal ion. This group of compounds are all class II mixed valence species from their colours, but do not show evidence of linkage isomerism or redox changes compared to the starting materials. The Mossbauer linewidths are consistent with the Ludi model of Prussian Blue.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24978/1/0000405.pd

Towards Designing an Integrated Earth Observation System for the Provision of Solar Energy Resource and Assessment

The GEOSS strategic plan specifically targets the area of improved energy resource management due to the importance of these to the economic and social viability of every nation of the world. With the world s increasing demand for energy resources, the need for new alternative energy resources grows. This paper overviews a new initiative within the International Energy Agency that addresses needs to better manage and develop solar energy resources worldwide. The goal is to provide the solar energy industry, the electricity sector, governments, and renewable energy organizations and institutions with the most suitable and accurate information of the solar radiation resources at the Earth's surface in easily-accessible formats and understandable quality metrics. The scope of solar resource assessment information includes historic data sets and currently derived data products using satellite imagery and other means. Thus, this new task will address the needs of the solar energy sector while at the same time will serve as a model that satisfies GEOSS objectives and goals

Discovery of Novel Cyclic Ethers with Synergistic Antiplasmodial Activity in Combination with Valinomycin

With drug resistance threatening our first line antimalarial treatments, novel chemotherapeutics need to be developed. Ionophores have garnered interest as novel antimalarials due to their theorized ability to target unique systems found in the Plasmodium-infected erythrocyte. In this study, during the bioassay-guided fractionation of the crude extract of Streptomyces strain PR3, a group of cyclodepsipeptides, including valinomycin, and a novel class of cyclic ethers were identified and elucidated. Further study revealed that the ethers were cyclic polypropylene glycol (cPPG) oligomers that had leached into the bacterial culture from an extraction resin. Molecular dynamics analysis suggests that these ethers are able to bind cations such as K+, NH4+ and Na+. Combination studies using the fixed ratio isobologram method revealed that the cPPGs synergistically improved the antiplasmodial activity of valinomycin and reduced its cytotoxicity in vitro. The IC50 of valinomycin against P. falciparum NF54 improved by 4–5-fold when valinomycin was combined with the cPPGs. Precisely, it was improved from 3.75 ± 0.77 ng/mL to 0.90 ± 0.2 ng/mL and 0.75 ± 0.08 ng/mL when dosed in the fixed ratios of 3:2 and 2:3 of valinomycin to cPPGs, respectively. Each fixed ratio combination displayed cytotoxicity (IC50) against the Chinese Hamster Ovary cell line of 57–65 µg/mL, which was lower than that of valinomycin (12.4 µg/mL). These results indicate that combinations with these novel ethers may be useful in repurposing valinomycin into a suitable and effective antimalarial

Impairment of Methotrexate Transport Is Common in Osteosarcoma Tumor Samples

Osteosarcoma does not respond well to conventional dose methotrexate but does respond to high-dose methotrexate. Previous work has indicated that this resistance may be due to impaired transport of methotrexate across the cell membrane. In this study, the PT430 competitive displacement assay was adapted to evaluate methotrexate transport in 69 high-grade osteosarcoma tumor samples. All samples studied were shown to have relatively impaired methotrexate transport by PT430 assay. Ninety-nine percent of the samples had less than 20% PT430 displacement by methotrexate. Eighty-eight percent exhibited displacement by methotrexate at less than 50% of the displacement by trimetrexate. The high frequency of impaired transport suggests the presence of decreased functionality of the reduced folate carrier protein. The overwhelming presence of impaired transport may explain why methotrexate needs to be given in high doses to be effective in osteosarcoma therapy and suggests that reduced folate carrier-independent antifolates should be explored